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12,000 MTPA DIMETHYL CARBONATE PRODUCTION USING METHANOL AND UREA
A PROJECT REPORT submitted in partial fulfilment of the requirement for the award of the degree of
BACHELOR OF TECHNOLOGY In
CHEMICAL ENGINEERING By:
RAHUL SHRIVASTAV (14111032) (GROUP 1, Production Factor 1)
DEPARTMENT OF CHEMICAL ENGINEERING INDIAN INSTITUTE OF TECHNOLOGY ROORKEE
CERTIFICATE This is to certify that the project titled – Dimethyl Carbonate Production using Methanol and Urea which is hereby presented by Group 1 in partial fulfillment of the requirements of the awarding of the degree of Bachelor of Technology at Indian Institute of Technology Roorkee, is a genuine account of his work carried out during the period from October 2017 to April 2018 under our supervision and guidance.
Date: April 16, 2018
Prof. Shishir Sinha Head of Department Department of Chemical Engineering IIT Roorkee
Dr. Vimal Chandra Srivastava Associate Professor Department of Chemical Engineering IIT Roorkee
DEPARTMENT OF CHEMICAL ENGINEERING INDIAN INSTITUTE OF TECHNOLOGY ROORKEE
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ACKNOWLEDGEMENT
It is with a deep sense of gratitude and indebtedness that we express our sincere gratefulness to our project guide Dr. V.C. Srivastava, Associate Professor, Department of Chemical Engineering, Indian Institute of Technology Roorkee, under whose able guidance, constant supervision and encouragement, this work has been accomplished. We thank him for taking time out of his busy schedule and aiding us with his priceless suggestions, encouragement and cooperation, which in turn helped us, enhance the scientific merit of the present project work. Without his guidance and mentorship, this work would have never reached its completion. The constant motivation and support from him made us understand the depths of various techniques and processes being used in current scenario. We’d also like to thank our Institution and entire staff of Central Library, IIT Roorkee and Departmental Library, IIT Roorkee who provided us with facilities for various books, research papers and internet.
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Index
I. General II. Summary Executive summary of the project… ............................................................................................ 6 III. Project Details 1. Introduction .............................................................................................................................. 8 2. Project Description...................................................................................................................9 a. Uses and present status of the product/importance of the problem ................................. 9 b. (i) Available processes for the production of the product with brief description… ......... 10 (ii) Techno-economic appraisal of alternative processes/schemes… ............................... 13 (iii) Status of technologies/schemes available .................................................................. 13 (iv) Selection of technology/scheme… ............................................................................ 14 (v) Source of knowhow of selected process/technology… ............................................... 16 c. Raw Materials ...................................................................................................................... 16 (i) Detailed specifications… ............................................................................................. 17 (ii) Requirement of raw materials… ................................................................................. 18 (iii) Availability: indigenous/imported… ......................................................................... 18 (iv) Government policies for import of the raw materials… ............................................ 21 (v) Prevailing prices… ..................................................................................................... 22 (vi) Testing procedures for the raw materials… .............................................................. 22
3. Material and Energy Flow Information .................................................................................... 23 a. Material balance b. Energy balance
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4. Detailed Design of Equipment ................................................................................................. 38 a. b. c. d. e.
Process design of all major equipment ............................................................................. 38 Mechanical design of three major equipment .................................................................. 79 Drawings of 2 equipment as per BIS specification of equipment Design of Auxiliary Equipment ....................................................................................... 97 Major engineering problems of the plant with their possible remedies… ....................... 98
5. Materials Storage & Handling Facilities..................................................................................99 6. Process Instrumentation & Control and Safety Aspects ......................................................... 113 IV. Environmental Protection & Energy Conservation ........................................................ 117 1. Environmental Aspects ........................................................................................................... 117 a. b. c. d.
Air Pollution…...............................................................................................................118 Liquid Effluents… ......................................................................................................... 122 Solids Disposal................................................................................................................125 Noise Pollution…............................................................................................................126
2. Energy Conservation .............................................................................................................. 129 a. Possible usage of renewable resources… ....................................................................... 129 b. Energy conservation options… ....................................................................................... 131 V. Plant ……………………………………………………………………………….131
Utilities
1. Air for Process and Instrumentation ....................................................................................... 131 2. Heat Transfer Media ............................................................................................................... 135 3. Water ....................................................................................................................................... 138 a. Process and general water requirement and standards… ................................................ 138 b. Water treatment and storage facilities c. Cooling tower/spray ponds 4. Refrigeration… ....................................................................................................................... 139 5. Electricity/Power…..................................................................................................................141 VI. Organizational Structure and Manpower Requirement ................................................ 142 1. Organizational structure with chart 2. Manpower requirement
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VII. Market Prospects .............................................................................................................. 146 1. A brief analysis of demand and supply… ....................................................................... 146 2. Present production capacity… ........................................................................................ 148 3. Export potential (if any). ................................................................................................. 151 4. Marketing set-up and area of consumption… ................................................................. 152 VIII Site Selection & Project Lay-out ..................................................................................... 153 1. Critical points taken into consideration . 2. A plot lay-out of works
IX. Economic Evaluation & Profitability of the Project ....................................................... 162 1. 2. 3. 4. 5. 6.
Total project cost Detailed statement indicating the cost of production Cash flow chart Break Even point with detailed calculation Full justification of the selling price taken in the preparation of cash flow Implementation schedule
X. References ............................................................................................................................. 167 1. References should be given as per the guidelines of American Chemical Society Journals.
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II Executive Summary
This project is an attempt towards making a techno-economic evaluation of installing a 12,000 MTPA plant. For the production of dimethyl carbonate (DMC) using methanol and urea. The main advantage of this technology lies in the usage (for the production of urea) of carbon dioxide indirectly. This process can be used to convert a greenhouse gas, carbon dioxide, to a green chemical, dimethyl carbonate.
Cost Information Total Fixed Capital Investment (Rs)
748,297,830
Total Working Capital (Rs)
76,871,270
Production Cost (Rs)
3,052,855,820
Gross Profit (Rs)
605,144,120
Payback period: 1.74 years Selling Price at 100 % Production:
Employment Potential The organization consists of 6 divisions, namely Administration, Personal (HR), Finance, Production, Technical and Maintenance.
Division
Number of Employees
Administration
14
Personal (HR)
5
Finance
5
DEPARTMENT OF CHEMICAL ENGINEERING INDIAN INSTITUTE OF TECHNOLOGY ROORKEE
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Production
63
Technical
33
Maintenance
19
The plant has a total employment potential of 135 people.
Utilities
S.No
Utility
Consumption
Rate, in $
Cost(per year $)
1
Steam(in ton)
579906
17.14 per ton
9,939,589
2
Power(in kwh)
97270272
50.07 $/ kWh
7,642,660
3
Water(in m3)
18272211.9
0.42 per m3
7,674,329
Total
25,256,578
Profitability of the Project A minimum return rate of 13.41 % is assured. For a break even, annual sales is 4208 tonnes per year.
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III. Project Details
3.1. Introduction 3.1.1 Problem Statement and description The project demands a Technical and Economic feasibility report checking for a proposed project which will produce dimethyl carbonate from methanol and urea. Emphasis is to be laid on the fact that owing to the multiple uses of dimethyl carbonate and limited competition in the market, it offers huge export potential in the near future. As part of this project the following are to be detailed out : 1. Project details and technology 2. Material and Energy flow information 3. Detailed design of equipments ( Process and Mechanical) 4. Material storage and handling facilities 5. Environment protection and energy conservation 6. Plant utilities 7. Organisational structure and manpower requirement 8. Market prospects 9. Site selection and project layout 10. Economic evaluation and profitability of the project
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3.1.2 Introduction to the format of the report The complete report has been extended to a Span of seven chapters, each chapter focusing on dimension of the project.
● The first chapter covers summary of the project. ● The second chapter covers project details and problem statement analysis. ● The third chapter is the heart of the project. It is subdivided into three sections, each dealing with a distinct topic. The chapter cover problem statement and description, a brief literature review on various available process for production and basis of the final process selection. Requirement, availability, specification and testing procedures for the raw materials are also mentioned here. The next section in this chapter includes exhaustive process designing of all the major equipments in the plant. Mechanical designs of the some of the equipments have also been presented. Besides, the major engineering problems of the plant and their possible remedies are also discussed ● The fourth chapter deals with environmental protection and energy conservation in the plant. Possible sources of the pollutants of the all kinds are investigated and their mitigation measure is suggested. ● Chapter five discusses in full detail the utilities involved in the plant. Considerations are taken or various type of utilities their application range and their general facilities. ● Chapter Six discusses the market prospects of the DiMethyl carbonate. ● Site selection and project layout is covered in the seventh chapter. Alternative feasibility sites and weighed and best site selected. A plant layout of the works showing mandatory requirement is also attached. ● Chapter eight deals with assessment of the economic viability of the project. It shows in detail the project cost estimation cash flow diagram, break even point analysis and implementation schedule. ●
The ninth chapter encompasses the organization structure and manpower requirement of the project.
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3.2. Project Description 3.2.a Uses and present status of the product Dimethyl carbonate (DMC) (CH3OCOOCH3) has been considered as an environmentally benign chemical and applied widely during the last few years because of its low toxicity and quick biodegradation properties. Following are some of the uses of this ‘Green Chemical’. ● DMC is an important carbonylation and methylating reagent used in various fields such as medicine, pesticides, composite materials, flavouring agent and electronic chemicals. ● It is considered as an additive for gasoline due to the enhancement of the octane number. ● It can be used as a polar solvent in the chemical industry. ● Paints and Coatings : Dimethyl Carbonate can be used as VOC exempt solvent in many paints and coatings. DMC is a fast evaporating polar solvent. It can replace esters, glycol ethers and ketones in formulations. ● Fuel Additive : Because of its high oxygen content, DMC can be used as a fuel additive. ● Li-ion Battery : Lithium ion battery electrolytes use organic carbonates such as diethyl carbonate and complexes of lithium ions. Although processes for the production of DMC are well-established, for example phosgenation of methanol, oxidative carbonylation of methanol, and trans esterification of ethylene carbonate with methanol; the synthesis of DMC utilizing CO2 is an option worth investigating since all these techniques suffer from corresponding drawbacks such as toxicity, explosion hazards, reaction routine complex, and low conversion, respectively. Therefore, it is desirable to focus on new processes to avoid these shortcomings.
3.2.b.(i) Available processes for the production of DMC Methods for the production of DMC can be classified into two: Conventional and Nonconventional methods.
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Conventional Routes: ● Phosgene Route, ● BAYER Route (Partial carbonylation of methanol) Non-conventional Routes: These are CO2 based routes of production. ● Urea Route ● Synthesis from CO2 and Methanol ● Propylene Carbonate Route ● Ethylene Carbonate Route
Phosgene Route This process employs the traditional (pre-1980) method to produce DMC. Here phosgene reacts with methanol to form methyl chloroformate (CH3OCOCl), which further reacts with methanol to form DMC. COCl2 + 2 CH3OH ⇌ (CH3O)2CO+ 2 HCl
Partial carbonylation of methanol This non-phosgene process produces DMC by reacting methanol, carbon monoxide and oxygen in liquid phase, in the presence of a catalyst. The process has been licensed by BAYER for commercial production of DMC. CO + ½ O2 + 2 CH3OH ⇌ (CH3O)2CO + H2O
Urea Route
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In this process, methanol is added to urea for the alcoholysis reaction to produce DMC. It has been reported that the process involves a two-step reaction with methyl carbamate as the reaction intermediate. NH2CONH2 + CH3OH ⇌ NH2COOCH3 + NH3 NH2COOCH3 + CH3OH ⇌ CH3OCOOCH3 + NH3
Synthesis from CO2 and Methanol For the direct use of CO2 to produce DMC, it has been reported that CO2 could react with methanol at critical temperature and critical pressure of CO2 . Under mild conditions, a basic catalyst (ZrO2–MgO), a promoter (methyl iodide) and butylene oxide as a chemical trap to shift the chemical equilibrium are needed (Eta et al., 2011). CO2 + 2 CH3OH ⇌ (CH3O)2CO + H2O Propylene Carbonate Route DMC can be obtained through the transesterification of propylene carbonate and methanol. Various types of catalysts can be used such as basic quaternary ammonium ion exchange resins with hydroxide counterions. C3H6O + CO2 ⇌ CH3(C2H3O2)CO CH3(C2H3O2)CO + 2 CH3OH ⇌ (CH3O)2CO + C3H8O2
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Ethylene Carbonate Route Transesterification of ethylene carbonate with methanol produces DMC and ethylene glycol. Various types of catalysts can be used, such as poly-4-vinyl pyridine as a novel base catalyst and DABCO-derived (1,4-diazobicyclo[2.2.2]octane) basic ionic liquids. C2H4O + CO2 ⇌ (CH2O)2CO (CH2O)2CO + 2 CH3OH ⇌ (CH3O)2CO + (CH2OH)2
3.2.b.(ii) Techno-Economic appraisal of alternate processes : DMC can be used as a precursor for carbonic acid derivatives and as a methylating agent. Because of its high oxygen content, DMC has been proposed as a replacement for methyl tertbutyl ether (MTBE) as a fuel additive. The process of oxidative carbonylation of methanol on unsupported cuprous chloride suffers from catalyst deactivation, equipment corrosion, and difficulties in product separation, a number of alternative approaches have been investigated. These include cycloaddition of CO2 to epoxides with the use of titanosilicate molecular sieves, various transesterification methods, methanol carboxylation over zirconia, and electrochemical oxidative carbonylation of methanol . From a thermodynamic standpoint, the oxidative carbonylation of methanol remains the most favorable reaction. To overcome problems with catalyst separation inherent in liquid-phase processes, recent interest has focused on vapor-phase oxidative carbonylation of methanol over supported copper-based catalysts. CuCl and CuCl2 supported on activated carbon have been evaluated by a number of groups because of the inherent similarity of such catalysts to those used in the liquid-phase system . CuCl, CuCl2, and bimetallic PdCl2-CuCl2 deposited on mesoporous silica supports (HMS silica, MCM-41, and SBA-15) have also been evaluated.
3.2.b.(iii) Status of technologies/schemes available Although Phosgene route is a conventional route to produce DMC, phosgene is an extremely hazardous material and is classified by the US Department of Transportation (DOT) as a class-A
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poison. Therefore due to the inherent hazards and potential environmental problems in handling and waste disposal, it is crucial that this method is replaced by a more sustainable method. With regard to the BAYER Process, the process suffers from low production rate, difficulties in downstream separation because of the existence of binary azeotropes in the system methanolwater-DMC, and the need for corrosion resistant reactors. Urea route has many inherent advantages such as the consumption of CO2 as a raw material and the ability to recycle the waste NH3 stream for the production of Urea, thus making the process even more sustainable. DMC synthesis from the direct reaction of urea and methanol using bases, organic tin, metal oxides, and ionic liquids has been reported. However, the corresponding DMC yields were usually below 40% in the batch reactor.
3.2.b.(iv) Selection of Technology/Scheme: Compared to the traditional routes, Urea route is one such method that has many advantages such as ● Usage of CO2 as a raw material: This method is a potential strategy to counter the large scale emission of CO2 by using it as a chemical feedstock for conversion to more valuable chemical. ● Easy availability of raw material and safe operations: Having easily available raw materials such as urea and methanol is an advantage. Also this method does not involve any hazardous chemicals (like phosgene), thus it is inherently safer. ● Ammonia released during the reaction could be recycled for urea synthesis. Moreover urea synthesis can be integrated with the DMC production plant to enhance the sustainability of the overall process. In view of the above advantages, Urea route of DMC production was chosen for this project.
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Technical Details of the Urea Route of Production This manufacturing route comprises of two reactions:NH2CONH2 + CH3OH → NH2COOCH3 + NH3 NH2COOCH3 + CH3OH → CH3OCOOCH3 + NH3 The intermediate methyl carbamate (MC) (NH2COOCH3) is produced first and further converted to DMC by the consecutive reaction with methanol. Different catalytic studies performed for DMC synthesis from urea and methanol were studied from the literature. Zn-based catalysts have been widely recommended for the synthesis of DMC from urea or MC. DMC is produced by the reaction of urea with methanol via intermediate methyl carbamate (MC). In addition, ammonia released during reaction could be recycled for urea synthesis. No poisonous or corrosive gases were involved in this approach, and naturally abundant carbon dioxide was used as one of the starting materials. Those features made the direct carbonate synthesis more attractive from the environmental perspective. Catalysts in the direct synthesis method reported in the literature were bases,16,17 organotin catalysts,18-21 and metal oxides.16,17,22-24 The corresponding DMC yields were usually low (below 40%) in the batch reactors. Ryu et al.19 have patented a novel process, in which DMC was withdrawn during reaction via a reflux column above an autoclave reactor in the presence of organotin catalysts. A high DMC selectivity was obtained, but the organotin and cocatalyst were very complex, expensive, and difficult to handle. Sun25 and his co-workers reported a new process using polyphosphoric acid as the catalyst as well as an ammonia captor. The DMC yield in the batch operation was improved. Ammonium polyphosphate was however precipitated in the reactor during reaction, which caused problems in operation and separation. In our previous work, ZnO exhibited high activity toward the DMC synthesis.17 It was simple and nontoxic in comparison with the tin compounds. In this work, a new strategy was proposed for the DMC synthesis from urea and methanol based on the analysis of thermodynamic equilibrium and side reactions. The
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objective was to increase the DMC yield using catalytic distillation technique over a Zn-based catalyst. 3.2.b.(v) Source or know how of selected process/technology ● Pichayapan
Kongpannaa,
Varong
Pavarajarnb,
Rafiqul
Ganic,
Suttichai
Assabumrungrata: Techno-economic evaluation of different CO2-based processes for dimethyl carbonate production ● Dengfeng Wang,Xuelan Zhang, Wei Wei, Yuhan Sun2: Synthesis of Dimethyl Carbonate from Methyl Carbamate and Methanol Using a Fixed-Bed Reactor ● Kartikeya Shukla and Vimal Chandra Srivastava: Synthesis of organic carbonates from alcoholysis of urea: A Review
3.2.c Raw Materials (i) Detailed specifications Urea: Urea Specifications CAS No.
57-13-6
State
Prilled
Molecular weight:
60.60 g/mol
Water solubility:
Soluble
Density
1.335g/cm3
Urea Coating:
No anti-caking agent
MF
CH4N2O
Melting point
132.7°C
Nitrogen
46.60%
Moisture
0.36%
Biuret
0.80%
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Alkalinity (NH3)
0.02%
Aldehyde
0.8 mg/kg
Insoluble matter
11 mg/kg
Iron (Fe)
0.46 mg/kg
Source:https://www.alibaba.com/product-deta Methanol: Methanol Specifications CAS No.
67-56-1
Appearance
colorless, transparent
Molecular weight:
32.04 g/mol
Melting point
-97.8°C
Boiling Point
64.7°C
Relative Density
0.7914
Refractive Index
1.3287
Flash Point
16°C
Table No 3.2.1 Test Items
Standard
Results
Titratable Acid. mmol/g
Max 0.0005
0.0003
Titratable Base. mmol/g
Max 0.0002
0.00008
Solubility in H2O
Pass test
Pass test
UV Absorbance,(1.00-cm cell vs.water) at 205 nm
Max 1.00
0.708
at 210 nm
Max 0.60
0.411
at 220 nm
Max 0.30
0.197
at 230 nm
Max 0.15
0.086
at 240 nm
Max 0.05
0.033
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at 260 nm
Max 0.01
0.006
Source:https://www.alibaba.com/product-detail/industrial-methanol 3.2.c.(ii) Requirement of raw materials and basic assumptions made in computing the raw material requirement for producing 12,000 TPA DMC Amount of Urea required: 12,000 TPA Amount of Methanol required: 16,380 TPA Computation and basic assumptions:After reviewing the literature, a conversion of 40% was taken for calculation of raw material. Using 12,000 TPA DMC, moles produced were calculated, which were back substituted to find the theoretical moles of raw materials required. The actual moles required was calculated by back substitution, using the yield data. Finally a 5% provision was included for the unavoidable losses and the molar data was converted back to MMTPA.
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3.2.c.(iii) Availability: indigenous/imported Urea: Import of Urea in last few Years
Production of Urea in last few Years
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Methanol: Methanol Stats for Imports, exports and net Imports
Methanol stats Indian capacity, consumptions and domestic production
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3.2.c.(iv) Government Policies on Import of raw materials Urea: Policies on import of urea have seen many changes with the change in government every five years Subsidy Provided by the government of india Internal Product: 13,700₹ per Metric Ton Imports: 37,898₹ per Metric Ton
Sr .no
Acts/Sections
Subject
1
Fertilizer Control Order, 1985
This has been issued under the Essential Commodities Act, 1955 and is administered by Department of Fertilizers in the Ministry of Chemicals and Fertilizers, Govt. of India. The FCO lays down as to what substances qualify for use as fertilizers in the soil, product-wise specifications, methods for sampling and analysis of fertilizers, procedure for obtaining license/registration as manufacturer/importer/dealer in fertilizers and conditions to be fulfilled for trading thereof, etc.
2
ITC (HS)- Schedule I and 2
Under ITC (HS) Code 31021000, it provides that import and export of Urea is restricted. ● Urea other than Industrial grade/Technical Grade can be imported by STE only. Industrial grade/Technical grade urea can be imported without license subject to actual user condition. ● Export of Urea is restricted and requires export licence from office of the DGFT.
3
DGFT notification No. 4 /2015-2020,dated 28.04.2015 [Issued under Para 1.02 and 2.01 of FTP read with Section 3 of the FT (D&R) Act, 1992 (Administrative Ministry: Ministry of Commerce & Industry, Department of Commerce).
It amends the ITC (HS) to provide that w.e.f. 28.04.2015, Import of Industrial Urea /Technical Grade Urea (TGU) is free, Subject to Actual User condition. Urea of grade other than Industrial/Technical grade can only be imported through State Trading Enterprises only.
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Methanol: There are no quantitative or other restriction on the import of methanol other than few obligations as per international convention. On Import of Methanol government of india imposes three tier tax scheme Basic Duty: 10% Countervailing Duty: 12% Special Countervailing Duty: 4%
(v) Prevailing Price Urea Price: 150$ per ton Methanol Price: 250$ per ton
(vi) Testing procedures for the raw materials Urea: In industries two major techniques are used to measure percentage purity of urea: ● Near-Infrared Spectroscopy Near-infrared spectroscopy (NIRS) is a spectroscopic method that uses the near-infrared region of the electromagnetic spectrum (from about 700 nm to 2500 nm). Typical applications include medical and physiological diagnostics and research including blood sugar, pulse oximetry, functional neuroimaging, sports medicine, elite sports training, ergonomics, rehabilitation, neonatal research, brain computer interface, urology (bladder contraction), and neurology (neurovascular coupling). There are also applications in other areas as well such as pharmaceutical, food and agrochemical quality control, atmospheric chemistry, combustion research and astronomy. ● Kjeldahl Method The Kjeldahl method or Kjeldahl digestion in analytical chemistry is a method for the quantitative determination of nitrogen contained in organic substances plus the nitrogen in inorganic ammonia and ammonium (NH3/NH4+). Other forms of inorganic nitrogen, for instance nitrate, are not included in this measurement. This method was developed by Johan in 1883.
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3. Material and Energy Flow Information
Material Balance Calculations Material Balance calculations were carried out using simulations in Aspen Plus software, except the reactor block, which was solved by hand calculations using the yield data reported in the research paper mentioned in the reference. HYSSRK method was used for calculations of all the unit operations. The material balance result obtained from simulation for all the individual unit operations is shown below.
Reactor
Process Specifications Reactor
REAC-IN
REAC-OUT
Temperature °C
53.32998
170
Pressure bar
1
1
Vapor Frac
1
1
Liquid Frac
0
0
NH3
6.096876
95.13
METHANOL
1320.574
1265.84
0
0
Material Balances Component Molar Flow kmol/hr
WATER
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DMC
0.0662855
19.59
0.00E+00
32.49
69
0
Total Flow kmol/hr
1395.737
1413.05
Total Flow kg/hr
46567.69
46383.94
-169620000
-183750000
-65761000
-72125000
MC UREA
Enthalpy Balances
Enthalpy J/kmol Enthalpy Watt
Cooler
Process Specifications Cooler
REAC-OUT
COLD-STR
Temperature °C
170
80
Pressure bar
1
1
Vapor Frac
1
0.9812263
Liquid Frac
0
0.0187737
95.13
95.13
1265.84
1265.84
0
0
19.59
19.59
Material Balances Component Molar Flow kmol/hr NH3 METHANOL WATER DMC
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MC
32.49
32.49
0
0
1413.05
1413.05
46383.94
46383.94
-183750000
-189300000
-72125000
-74305000
UREA Total Flow kmol/hr Total Flow kg/hr
Enthalpy Balances
Enthalpy J/kmol Enthalpy Watt
Distillation Column 1
Process Specifications
Distillation C-1
COLD-STR
DC1-BTM
DC1-TOP
Temperature °C
80
107.3366
32.75723
Pressure bar
1
1
1
Vapor Frac
0.9812263
0
0
Liquid Frac
0.0187737
1
1
Material Balances Mole Flow kmol/hr
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NH3
95.13
7.08E-10
95.13
1265.84
8.975058
1256.865
0
0
0
DMC
19.59
0.9264426
18.66356
MC
32.49
32.49
6.91E-08
0
0
0
1413.05
42.3915
1370.659
46383.94
2809.968
43573.98
-189300000
-89996000
-234270000
-74305000
-1059700
-89196000
METHANOL WATER
UREA Total Flow kmol/hr Total Flow kg/hr
Enthalpy Balances
Enthalpy J/kmol Enthalpy Watt
Pump
Process Specifications Pump
DC1-TOP
LIQ-1
Temperature °C
32.75723
33.47633
Pressure bar
1
30
Vapor Frac
0
0
Liquid Frac
1
1
Material Balances
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Component Molar Flow kmol/hr NH3
95.13
95.13
1256.865
1256.865
0
0
DMC
18.66356
18.66356
MC
6.91E-08
6.91E-08
0
0
Total Flow kmol/hr
1370.659
1.37E+03
Total Flow kg/hr
43573.98
43573.98
-234270000
-234080000
-89196000
-89124000
METHANOL WATER
UREA
Enthalpy Balances
Enthalpy J/kmol Enthalpy Watt
Distillation Column 2
Process Specifications
Distillation C-2
LIQ-1
DC2-BTM
DC2-TOP
Temperature °C
33.47633
190.4547
170.302
Pressure bar
30
30
30
DEPARTMENT OF CHEMICAL ENGINEERING INDIAN INSTITUTE OF TECHNOLOGY ROORKEE
27
Vapor Frac
0
0
0
Liquid Frac
1
1
1
95.13
0.00486213
86.06514
1256.865
223.7292
913.4251
0
0
0
DMC
18.66356
16.84841
0.043145
MC
6.91E-08
6.25E-08
1.22E-27
0
0
0
Total Flow kmol/hr
1.37E+03
240.5825
999.5334
Total Flow kg/hr
43573.98
8686.536
30737.74
-234080000
-244220000
-208110000
-89124000
-16321000
-57780000
Material Balances Mole Flow kmol/hr NH3 METHANOL WATER
UREA
Enthalpy Balances
Enthalpy J/kmol Enthalpy Watt
Valve
Process Specifications Valve
DC2-BTM
DC3-IN
Temperature °C
190.4547
170.4644
Pressure bar
30
20
0
0.134518
Vapor Frac
DEPARTMENT OF CHEMICAL ENGINEERING INDIAN INSTITUTE OF TECHNOLOGY ROORKEE
28
Liquid Frac
1
0.865482
0.00486213
0.00537384
223.7292
247.2865
0
0
DMC
16.84841
18.61589
MC
6.25E-08
6.91E-08
0
0
Total Flow kmol/hr
240.5825
265.9077
Total Flow kg/hr
8686.536
9600.582
-244220000
-244220000
-16321000
-18039000
Material Balances Component Molar Flow kmol/hr NH3 METHANOL WATER
UREA
Enthalpy Balances
Enthalpy J/kmol Enthalpy Watt
Distillation Column 3
Process Specifications
Distillation C-3
DC3-IN
DC3-BTM
DEPARTMENT OF CHEMICAL ENGINEERING INDIAN INSTITUTE OF TECHNOLOGY ROORKEE
DC3-TOP
29
Temperature °C
170.4644
210.7092
168.2422
Pressure bar
20
20
20
Vapor Frac
0.134518
0
0
Liquid Frac
0.865482
1
1
0.00537384
2.46E-16
0.00537384
247.2865
2.472865
244.8136
0
0
0
DMC
18.61589
18.59727
0.0186158
MC
6.91E-08
6.91E-08
0.00E+00
0
0
0
Total Flow kmol/hr
265.9077
21.07014
244.8376
Total Flow kg/hr
9600.582
1754.457
7846.126
-244220000
-531560000
-223200000
-18039000
-3111100
-15180000
Material Balances Mole Flow kmol/hr NH3 METHANOL WATER
UREA
Enthalpy Balances
Enthalpy J/kmol Enthalpy Watt
Valve 2
Process Specifications
DEPARTMENT OF CHEMICAL ENGINEERING INDIAN INSTITUTE OF TECHNOLOGY ROORKEE
30
Valve 2
DC3-TOP
S6
Temperature °C
168.2422
66.76251
Pressure bar
20
1
Vapor Frac
0
0.3714046
Liquid Frac
1
0.6285954
0.00537384
0.00537384
244.8136
244.8136
0
0
0.0186158
0.0186158
0.00E+00
0.00E+00
0
0
Total Flow kmol/hr
244.8376
244.8376
Total Flow kg/hr
7846.126
7846.126
-223200000
-223200000
-15180000
-15180000
Material Balances Component Molar Flow kmol/hr NH3 METHANOL WATER DMC MC UREA
Enthalpy Balances
Enthalpy J/kmol Enthalpy Watt
Cooler 2
Process Specifications
DEPARTMENT OF CHEMICAL ENGINEERING INDIAN INSTITUTE OF TECHNOLOGY ROORKEE
31
Cooler 2
S6
S7
Temperature °C
66.76251
15
Pressure bar
1
1
Vapor Frac
0.3714046
0
Liquid Frac
0.6285954
1
0.00537384
0.00537384
244.8136
244.8136
0
0
0.0186158
0.0186158
0.00E+00
0.00E+00
0
0
Total Flow kmol/hr
244.8376
244.8376
Total Flow kg/hr
7846.126
7846.126
-223200000
-243600000
-15180000
-16568000
Material Balances Component Molar Flow kmol/hr NH3 METHANOL WATER DMC MC UREA
Enthalpy Balances
Enthalpy J/kmol Enthalpy Watt
Distillation Column 4
DEPARTMENT OF CHEMICAL ENGINEERING INDIAN INSTITUTE OF TECHNOLOGY ROORKEE
32
Process Specifications
Distillation C-4
DC3-BTM
DC4-BTM
DC4-TOP
Temperature °C
210.7092
218.6633
174.626
Pressure bar
20
20
20
Vapor Frac
0
0
0
Liquid Frac
1
1
1
NH3
2.46E-16
0
0
METHANOL
2.472865
0.2834277
2.189437
0
0
0
DMC
18.59727
18.04759
0.5496806
MC
6.91E-08
6.91E-08
3.36E-20
0
0
0
Total Flow kmol/hr
21.07014
18.33102
2.739118
Total Flow kg/hr
1754.457
1634.788
119.6689
-531560000
-566290000
-293810000
-3111100
-2883500
-223550
Material Balances Mole Flow kmol/hr
WATER
UREA
Enthalpy Balances
Enthalpy J/kmol Enthalpy Watt
Flash
DEPARTMENT OF CHEMICAL ENGINEERING INDIAN INSTITUTE OF TECHNOLOGY ROORKEE
33
Process Specifications Flash
DC2-TOP
S9
S10
Temperature °C
170.302
61.74774
61.74774
Pressure bar
30
1
1
Vapor Frac
0
1
0
Liquid Frac
1
0
1
NH3
86.06514
89.93245
5.192178
METHANOL
913.4251
381.7845
627.794
0
0
0
DMC
0.043145
0.0142802
0.0333893
MC
1.22E-27
0
0
0
0
0
Total Flow kmol/hr
999.5334
471.7312
633.0195
Total Flow kg/hr
30737.74
13766.09
20207.31
-208110000
-169930000
-236550000
-57780000
-22267000
-41596000
Material Balances Component Molar Flow kmol/hr
WATER
UREA
Enthalpy Balances
Enthalpy J/kmol Enthalpy Watt
DEPARTMENT OF CHEMICAL ENGINEERING INDIAN INSTITUTE OF TECHNOLOGY ROORKEE
34
Distillation Column 5
Process Specifications
Distillation C-5
S9
DC5-BTM
DC5-TOP
Temperature °C
61.74774
65.29137
8.025282
Pressure bar
1
1
1
Vapor Frac
1
0
1
Liquid Frac
0
1
0
NH3
89.93245
0.8993245
89.03312
METHANOL
381.7845
377.9666
3.817845
0
0
0
0.0142802
0.0142802
0
MC
0
0
0
UREA
0
0
0
Total Flow kmol/hr
471.7312
378.8802
92.85097
Total Flow kg/hr
13766.09
12127.47
1638.616
Material Balances Mole Flow kmol/hr
WATER DMC
Enthalpy Balances
DEPARTMENT OF CHEMICAL ENGINEERING INDIAN INSTITUTE OF TECHNOLOGY ROORKEE
35
Enthalpy J/kmol Enthalpy Watt
-169930000
-237120000
-52944000
-22267000
-24956000
-1365500
Mixer
Process Specifications Mixer
DC5-BTM
S7
S10
FEED
REAC-IN
Temperature °C
65.29137
15
61.74774
25
533.2998
Pressure bar
1
1
1
1
1
Vapor Frac
0
0
0
0.5035971
1
Liquid Frac
1
1
1
0.4964029
0
0.8993245
0.00537384
5.192178
0
6.096876
377.9666
244.8136
627.794
70
1320.574
0
0
0
0
0
0.0142802
0.0186158
0.0333893
0
0.0662855
MC
0
0.00E+00
0
0
0.00E+00
UREA
0
0
0
69
69
378.8802
244.8376
633.0195
139
1395.737
Material Balances Component Molar Flow kmol/hr NH3 METHANOL WATER DMC
Total Flow kmol/hr
DEPARTMENT OF CHEMICAL ENGINEERING INDIAN INSTITUTE OF TECHNOLOGY ROORKEE
36
Total Flow kg/hr
12127.47
7846.126
20207.31
6386.79
46567.69
-237120000
-243600000
-236550000
449571000
-169620000
-24956000
-16568000
-41596000
17358400
-65761000
Enthalpy Balances
Enthalpy J/kmol Enthalpy Watt
Distillation Column 6
Process Specifications Distillation C-6
DC1-BTM
S3
MC
Temperature C
107.3366
67.51201
188.175
Pressure bar
1
1
1
Vapor Frac
0
0
0
Liquid Frac
1
1
1
NH3
6.06E-10
6.06E-10
1.65E-15
METHANOL
7.691363
7.651949
0.0394145
0
0
0
0.7940368
0.7027648
0.091272
27.85
0.00242851
27.84757
0
0
0
36.3354
8.357142
27.97826
Material Balances Mole Flow kmol/hr
WATER DMC MC UREA Total Flow kmol/hr
DEPARTMENT OF CHEMICAL ENGINEERING INDIAN INSTITUTE OF TECHNOLOGY ROORKEE
37
Total Flow kg/hr
2408.596
308.6715
2099.925
-89986000
-267510000
-26914000
-908240
-621010
-209170
Enthalpy Balances
Enthalpy J/kmol Enthalpy Watt
3.4. Material Storage and Handling Facilities a. Distillation Column 1 Design Column Diameter Column Specifications:Feed (F): 33.6mol/s Reflux Ratio (R): 1.5 Distillate Rate (D): 19.6 mol/s Bottoms Rate (B): 13.9 mol/s No. of real stages: 36
Flow rate Calculations:Rectifying section:V = D(1+R) = 19.6*(1+1.5) = 49 mol/s L = D x R = 19.6*1.5 = 29.4 mol/s Stripping Section:L′m = L + liq part of F = 29.4 + 33.6 = 63 mol/s V ′m = V - vapor part in F = 49 - 0 = 49 mol/s DEPARTMENT OF CHEMICAL ENGINEERING INDIAN INSTITUTE OF TECHNOLOGY ROORKEE
38
Calculation of Column Diameter: ρV F bottom = L′m = 19.05 x V ′m
LV
F LV
top =
L V
√
√
7.26
ρL
ρV ρL
=
19.05 x
√
400.05
1.25
√
= 0.109
720
= 0.002
1.01 755.09
Taking plate spacing as 0.45 m
Base K1 = 0.08 Top K 1 = 0 .078
Base uf = K 1 Top uf = K 1
√ √
ρL − ρV ρV ρL − ρV ρV
√ = 0.078 x √ = 0.08 x
720 − 1.25 = 1.25
1.92 m/s
755.09 − 1.01 1.01
= 2.13 m/s
Where uf = flooding velocity Actual velocity = 0.8 x flooding velocity Base actual vel = 1.536 m/s Top actual vel = 1.704 m/s
Net Area (base) =
Net Area (top) =
2 Max V apor volumetric f low rate = 2.98 m actual vel
2 Max V apor volumetric f low rate = 1.088 m actual vel
Taking downcomer area as 12% of the total, Total Area (base) A = Net Area c
0.88
2
= 0.121 m
DEPARTMENT OF CHEMICAL ENGINEERING INDIAN INSTITUTE OF TECHNOLOGY ROORKEE
39
Column Diameter (base) Dc = 2.076 m 2
Total Area (top) A = Net Area c
0.88
= 10.734 m
Column Diameter (top) Dc = 1.254 m As bottom diameter > top diameter Dc = 2.076 m
Provisional plate design Column diameter Dc =2.076 m Column area Ac = 3.383 m2 Downcomer area Ad = 0.12 x Ac = 0.406 m2 Net Area An = Ac − Ad
= 2.977 m2
Active area Aa = Ac - 2Ad = 2.571 m2
Taking Hole area Ah as 10 per cent of Aa = 0.20571 m2 (Initially Ah was taken as 5 % of Aa but in that case the weeping criteria was not met)
DEPARTMENT OF CHEMICAL ENGINEERING INDIAN INSTITUTE OF TECHNOLOGY ROORKEE
40
From the above graph, Weir length (lw) = 1.58m
Taking: weir height = 50mm Hole diameter = 5mm Plate thickness = 5mm
Check weeping
Maximum liquid rate = 7.37 kg/s Minimum liquid rate, at 70 per cent turn-down = 5.159 kg/s Lw,max 2/3 Maximum how =750x ( ρ l ) = 26.064mm liquid l w
Lw,min 2/3 Minimum how = 750x ( ρ l ) lw
= 20.55 mm liquid
At minimum rate hw + how = 50 + 20.55 =70.55 mm K2 = 30.5
DEPARTMENT OF CHEMICAL ENGINEERING INDIAN INSTITUTE OF TECHNOLOGY ROORKEE
41
Uh (min) =
k2−0.9(25.4−dh) = 12.08 m/s ρ v 0.5
Actual minimum vapor velocity =
minimum vapor rate = 27.81 m/s Ah
Actual vapour velocity > minimum vapour velocity → Satisfied !!
Plate Pressure Drop Dry plate drop Maximum vapour velocity through holes uh = 27.5 m/s Orifice Coefficient = 0.795 uh 2 ρv H = 51x ( ) = 85.6052 mm liquid d C 0 ρl
Residual head hr =
12500 = 17.36mm liquid ρl
Total plate pressure drop ht = 152.96 mm liquid
DEPARTMENT OF CHEMICAL ENGINEERING INDIAN INSTITUTE OF TECHNOLOGY ROORKEE
42
Downcomer liquid back-up
Downcomer pressure loss Take hap = hw – 10 = 40mm Area under apron, Aap = 40*3.675*10-3 = 0.0632m2 using Aap Lwl 2 = 166x ( ) = 4.35 mm Hdc ρl A m Back up in downcomer Hb = 233.374 mm liquid = 0.233 m ½ x (Plate spacing + Weir height) = 250 mm liquid So plate spacing is acceptable. Residence time tr = 2.26 x 0.225 x 785 / 19.82 = 9.24 s As tr is greater than 9.24 s hence satisfactory. Entrainment Uv = 2.47 m/s %flooding = UUn = 80.34 f
DEPARTMENT OF CHEMICAL ENGINEERING INDIAN INSTITUTE OF TECHNOLOGY ROORKEE
43
So φ = 0.09 (well below 0.1)
Perforated Area
θc = 1000 Angle subtended = 1800 -1000 = 800 Mean length = 2.83 m area of unperforated edge strips
= 0.1415 m2
Mean length of calming zone = 1.63m Area of calming zone = 0.163 m2
Total area = Ap = 2.2665 m2 Ah Ap
Lp
= 0.0907 =2.9
Dh
DEPARTMENT OF CHEMICAL ENGINEERING INDIAN INSTITUTE OF TECHNOLOGY ROORKEE
44
Area of each hole = 1.964x 10−5
Number of holes =
Ah = 10473 1.964x10−5
b. Distillation Column 3 Design Column Diameter Column Specifications:Feed (F): 73.91 mol/s Reflux Ratio (R): 1.77 Distillate Rate (D): 68.05 mol/s Bottoms Rate (B): 5.86 mol/s No. of real stages: 31
Flow rate Calculations:Rectifying section:V = D(1+R) = 68.50(1+1.177) = 188.49 mol/s L = D x R = 120.45 mol/s Stripping Section:L′m = L + liq part of F = 184.38 + 0 = 184.38 mol/s V ′m = V - vapor part in F = 188.49 - 10 = 178.5 mol/s
Calculation of Column Diameter: ρV F bottom = L′m = 184.38 x LV
V ′m
√
ρL
178.5
17.46
√
= 0.179
580.4
DEPARTMENT OF CHEMICAL ENGINEERING INDIAN INSTITUTE OF TECHNOLOGY ROORKEE
45
F LV
top =
ρV
L
V
√
ρL
=
184.38 x 188.49
23.5
√
= 0.126
600.6
Taking plate spacing as 0.45 m
Base K1 = 0.034 Top K 1 = 0 .061
Base uf = K 1 Top uf = K 1
√ √
ρL − ρV ρV ρL − ρV ρV
√ = 0.061 x √ = 0.034 x
580.4 − 17.46 = 17.46
600.6 − 23.5 23.5
0.19 m/s
= 0.30 m/s
Where uf = flooding velocity Actual velocity = 0.8 x flooding velocity Base actual vel = 0.15 m/s Top actual vel = 0.24 m/s Net Area (base) =
Net Area (top) =
2 Max V apor volumetric f low rate = 1.985 m actual vel
2 Max V apor volumetric f low rate = 1.062 m actual vel
Taking downcomer area as 12% of the total, Total Area (base) A = Net Area c
0.88
2
= 2.256 m
Column Diameter (base) Dc = 1.695 m Total Area (top) A = Net Area c
0.88
2
= 1.207 m
DEPARTMENT OF CHEMICAL ENGINEERING INDIAN INSTITUTE OF TECHNOLOGY ROORKEE
46
Column Diameter (top) Dc = 1.240 m As top diameter < bottom diameter Dc = 1.240 m
Provisional plate design Column diameter Dc = 1.69 m Column area Ac = 2.24 m2 Downcomer area Ad = 0.12 x Ac = 0.26 m2 Net Area An = Ac − Ad
= 1.97 m2
Active area Aa = Ac - 2Ad = 1.70 m2
Taking Hole area Ah as 10 per cent of Aa = 0.085 m2 (Initially Ah was taken as 5 % of Aa but in that case the weeping criteria was not met)
From the above graph, Weir length (lw) = 1.26m
DEPARTMENT OF CHEMICAL ENGINEERING INDIAN INSTITUTE OF TECHNOLOGY ROORKEE
47
Taking: weir height = 50mm Hole diameter = 5mm Plate thickness = 5mm
Check weeping
Maximum liquid rate = 0.57 kg/s Minimum liquid rate, at 70 per cent turn-down = 6.914 kg/s Lw,max 2/3 Maximum how =750x ( ρ l ) =280.36 mm liquid l w
Lw,min 2/3 Minimum how = 750x ( ρ l ) lw
= 25.41 mm liquid
At minimum rate hw + how = 50 + 25.41 =75.41 mm K2 = 30.7
Uh (min) =
k2−0.9(25.4−dh) = 2.958 m/s ρ v 0.5
Actual minimum vapor velocity =
minimum vapor rate = 3.149 m/s Ah
Actual vapour velocity > minimum vapour velocity → Satisfied !!
Plate Pressure Drop Dry plate drop Maximum vapour velocity through holes uh = 4.499 m/s
DEPARTMENT OF CHEMICAL ENGINEERING INDIAN INSTITUTE OF TECHNOLOGY ROORKEE
48
Orifice Coefficient = 0.805 uh 2 ρv H = 51x ( ) = 47.93 mm liquid d C 0 ρl
Residual head hr =
12500 = 21.54 mm liquid ρl
Total plate pressure drop ht = 144.88 mm liquid
Downcomer liquid back-up
Downcomer pressure loss Take hap = hw – 10 = 40mm
DEPARTMENT OF CHEMICAL ENGINEERING INDIAN INSTITUTE OF TECHNOLOGY ROORKEE
49
Area under apron, Aap = 40*3.675*10-3 = 0.05m2 using Aap Lwl 2 ) = 9.274 mm Hdc = 166x ( ρl A m Back up in downcomer Hb = 229.57 mm liquid ½ x (Plate spacing + Weir height) = 250mm liquid So plate spacing is acceptable. Residence time tr = 2.26 x 0.225 x 785 / 19.82 =5.36 s As tr is greater than 3 s hence satisfactory. Entrainment Uv = 0.13 m/s %flooding = UUn = 0.43 f
So φ = 0.179 (well below 0.1)
Perforated Area
DEPARTMENT OF CHEMICAL ENGINEERING INDIAN INSTITUTE OF TECHNOLOGY ROORKEE
50
θc = 1000 Angle subtended = 1800 -1000 = 800 Mean length = 2.288 m Area = 0.11 m2 Mean length of calming zone = 1.31m Area of calming zone = 0.131 m2 2 Total area = Ap = 1.458 m Ah Ap
= 0.058
Lp
=3.1
Dh
Area of each hole = 1.964x 10−5
Number of holes =
Ah = 4337.95 1.964x10−5
DEPARTMENT OF CHEMICAL ENGINEERING INDIAN INSTITUTE OF TECHNOLOGY ROORKEE
51
c. Distillation Column 4 Design Column Diameter Column Specifications:Feed (F): 5.86 mol/s Reflux Ratio (R): 6 Distillate Rate (D): 0.756 mol/s Bottoms Rate (B): 5.103 mol/s No. of real stages: 40
Flow rate Calculations:Rectifying section:V = D(1+R) = 0.756(1+6) = 5.292 mol/s L = D x R = 4.536 mol/s Stripping Section:L′m = L + liq part of F = 4.536 + 5.759 = 10.395 mol/s V ′m = V - vapor part in F = 5.292 - 0 = 5.292 mol/s
Calculation of Column Diameter: ρV F bottom = L′m = 10.395 x V ′m
LV
F LV
top =
ρV
L
V
√
√
ρL
5.292
ρL
=
10.395 x 5.292
17.46
√
353.2
43.44
√
= 0.491
= 0.295
366.41
Taking plate spacing as 1.45 m
DEPARTMENT OF CHEMICAL ENGINEERING INDIAN INSTITUTE OF TECHNOLOGY ROORKEE
52
Base K1 = 0.046 Top K 1 = 0 .056
Base uf = K 1 Top uf = K 1
√ √
ρL − ρV ρV ρL − ρV ρV
√ = 0.056 x √ = 0.046 x
353.2 − 17.46 = 17.46 366.41 − 43.44 43.44
0.17 m/s = 0.15 m/s
Where uf = flooding velocity Actual velocity = 0.8 x flooding velocity Base actual vel = 0.14 m/s Top actual vel = 0.12 m/s Net Area (base) =
Net Area (top) =
2 Max V apor volumetric f low rate = 0.119 m actual vel
2 Max V apor volumetric f low rate = 0.049 m actual vel
Taking downcomer area as 12% of the total, 2
Total Area (base) A = Net Area c
= 0.135 m
0.88
Column Diameter (base) Dc = 0.415 m 2
Total Area (top) A = Net Area c
0.88
= 0.049 m
Column Diameter (top) Dc = 0.25 m As top diameter < bottom diameter Dc = 0.25 m
DEPARTMENT OF CHEMICAL ENGINEERING INDIAN INSTITUTE OF TECHNOLOGY ROORKEE
53
Provisional plate design Column diameter Dc = 0.41 m Column area Ac = 0.131 m2 Downcomer area Ad = 0.12 x Ac = 0.015 m2 Net Area An = Ac − Ad
= 0.116 m2
Active area Aa = Ac - 2Ad = 0.100 m2
Taking Hole area Ah as 10 per cent of Aa = 0.005 m2 (Initially Ah was taken as 5 % of Aa but in that case the weeping criteria was not met)
From the above graph, Weir length (lw) = 0.30m
Taking: weir height = 50mm Hole diameter = 5mm Plate thickness = 5mm
DEPARTMENT OF CHEMICAL ENGINEERING INDIAN INSTITUTE OF TECHNOLOGY ROORKEE
54
Check weeping
Maximum liquid rate = 0.923 kg/s Minimum liquid rate, at 70 per cent turn-down = 0.646 kg/s Lw,max 2/3 Maximum how =750x ( ρ l ) =101.29 mm liquid l w
Lw,min 2/3 Minimum how = 750x ( ρ l ) lw
= 23.64 mm liquid
At minimum rate hw + how = 50 + 23.64 =73.64 mm K2 = 30.7\6
Uh (min) =
k2−0.9(25.4−dh) = 2.524 m/s ρ v 0.5
Actual minimum vapor velocity =
minimum vapor rate = 2.968 m/s Ah
Actual vapour velocity > minimum vapour velocity → Satisfied !!
Plate Pressure Drop Dry plate drop Maximum vapour velocity through holes uh = 4.24 m/s Orifice Coefficient = 0.805 uh 2 ρv H = 51x ( ) = 88.55 mm liquid d C 0 ρl
DEPARTMENT OF CHEMICAL ENGINEERING INDIAN INSTITUTE OF TECHNOLOGY ROORKEE
55
Residual head hr =
12500 = 35.39 mm liquid ρl
Total plate pressure drop ht = 160.56 mm liquid
Downcomer liquid back-up
Downcomer pressure loss Take hap = hw – 10 = 40mm Area under apron, Aap = 40*3.675*10-3 = 0.012m2 using Aap Lwl 2 Hdc = 166x ( ρ A ) = 7.518 mm l m Back up in downcomer Hb = 241.72 mm liquid ½ x (Plate spacing + Weir height) = 250 mm liquid So plate spacing is acceptable.
DEPARTMENT OF CHEMICAL ENGINEERING INDIAN INSTITUTE OF TECHNOLOGY ROORKEE
56
Residence time tr = 2.26 x 0.225 x 785 / 19.82 =1.52 s As tr is greater than 1.52 s hence satisfactory. Entrainment Uv = 0.046 m/s %flooding = UUn = 0.30 f
So φ = 0.0002 (well below 0.1) Perforated Area
θc = 980 Angle subtended = 1800 -1020 = 780 Mean length = 0.49 m Area = 0.02 m2 Mean length of calming zone = 0.357m Area of calming zone = 0.0357 m2
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2 Total area = Ap = 0.04 m Ah
= 0.125
Ap
Lp
=4.1
Dh
Area of each hole = 1.964x 10−5
Number of holes =
Ah = 255.31 1.964x10−5
REACTOR The feed components to the reactor are Urea and Methanol in the molar ratio of 1:20. The output stream from the reactor has methyl carbamate, methanol, dimethyl carbonate and ammonia in the molar ratio of 0.023, 0.89, 0.014 and 0.067 respectively. The operating conditions of the reactor are : T = 170 degree Celsius & P = 1 bar. At this temperature all the components are in gaseous state. Because of the low operating pressure and high temperature the gases are assumed to be ideal.
The output of the reactor and the input were related by the conversion data obtained from literature. Furthermore, the space time was obtained from a plot between mole fraction of DMC in output versus space time given in the literature.
Gas viscosities have been calculated as shown below while densities have been calculated using the equation : ρ=
PM RT
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μ =2.6693x10-5 √MT σ 2Ω M : Molecular Mass (kg/mol) σ : Characteristic diameter of molecule (A) Ω : Dimensionless constant μ : Viscosity (g/s.cm) T : Temperature (K) R : Universal gas constant
σ = 2.44( T Pc )0.33 c
T : Critical Temperature c Pc: Critical Pressure
ε kT
Ω is a function of
Components
. THe critical properties of various components are as follows :
Tc (K)
Pc(atm)
Methyl Carbamate
592.23
57.77
Methanol
513
78.5
Urea
638
76.34
DMC
557
147.13
Table 1 : critical temperatures and critical pressures
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59
Viscosity and density of the feed have been taken as the respective value of methanol since it is present in excess. The outlet stream viscosity and density has been calculated by multiplying viscosity and density of each component with its mole fraction.
Characteristic diameter Components
Ω
(Ȧ)
ε kT
Methyl Carbamate
5.30
1.0293
1.5735
Methanol
4.56
0.8916
1.6820
Urea
4.94
1.1089
1.5186
DMC
3.80
0.9681
1.6363
Table 2 : Ω & σ of various components
Components
Inlet mol fraction
Outlet mol fraction
Viscosity (Pa-s)
Density (kg/m3)
Methyl Carbamate
0
0.023
-6 11.008 X 10
2.0363
Methanol
029523
0.89
-6 11.81 X 10
0.881
Urea
0.0476
~0
DMC
0
0.067
-6 22.57 X 10
2.482
Table 3 : μ & ρ of various components
So the averaged viscosity and density of inlet and outlet streams are :
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Stream
Average viscosity (Pa-s)
Average Density (kg/m3)
Inlet
-6 9.092 X 10
881
Outlet
-6 8.69 X 10
0.866
Table 3 : μ & ρ of various streams
From literature, Space time τ = 0.3 kgcat h mol-1 Amount of catalyst (W )
cat Where τ is defined as τ = Feed molar f lowrate (F )
Hence Wcat = 0.3 X F = 398834.4 kg Wcat
Vcat = ρ cat
We are using ZnO pellets, both as the packing material as well as the catalyst ρcat = 5610 kg/m3 Wcat
Vcat = 5610 = 72 m3 Taking random packing density to be 62 % Volume of packed bed,
Vbed =
V cat = 116.1 m3 0.62
In order to ensure close temperature control, multi tubular fixed reactor was chosen
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All the reactor tubes were placed inside an enclosing shell with triangular pitch pitch was taken to be 1.25 times of diameter of individual tube (do) Number of total tubes that can be enclosed inside the enclosing shell was calculated using D n
Nt = K 1 (do b )1 where Nt = Total number of fixed bed tubes Db = Bundle diameter do = Diameter of individual fixed bed tube Using the above formula, following values were calculated after iterating for a multiple number of times, in order to obtain feasible reactor dimensions and keeping the constraint that πdo2 L 4
N t = V bed
where L = length of bed Using the above procedure following results were obtained, Two identical reactors would be placed in parallel with the following dimensions Db = 5 m do = 0.3 m NT = 132 L = 6.5 m
Pressure Drop Calculation Using Ergun’s Equation
ΔP L
=
150μ(1−ε2)v ε2 Dp 2
+
1.75(1−ε)ρv2 ε2Dp
ΔP : Pressure drop L : Length of each reactor column (m)
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μ : Fluid Viscosity (Pa-s) ε : void space of the bed V : superficial Velocity(m/s) Dp : Diameter of particle(m) ρ : Density (kg/m3) In our case : L = 6.5 m -6 μ = 8.85 x 10 Pa-s ε = 0.38 -4 V = net flow rate to each bed/ Area of bed = 7.67 x 10 m/sec Dp = 2 cm ρ = 873.5 (kg/m3) Calculating we get, ΔP = 2.08 Pa
Storage Facility BENZENE STORAGE TANK: Mass flow rate of Methanol = 2133.12 kg/hr Density = 792 kg/m3 Volumetric flow rate = 2.69 m3/hr Storage for 7 days (1 week) = 452.48 m3 Using standard dimensions from code:
[IS: 803-1976]
Height = 10.5 m Diameter = 7.5 m Volume = 463.57 m3
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UREA STORAGE TANK Mass flow rate of UREA = 3957.95 kg/hr Density = 1320 kg/m3 Volumetric flow rate = 2.99 m3/hr Storage for 7 days (1 week) = 503.73 m3 Using standard dimensions from code:
[IS: 803-1976]
Height = 4.5 m Diameter = 12 m Volume = 508 m3
FLASH Unit Specifications Feed: 32355.78 kg/hr (0.0156 m3/hr) Top Outlet (Vapor),V = 13110.67 kg/hr Density of V, ρv = 6.5 kg/m3 Bottom outlet (Liquid), L = 19245.11 kg/hr Density of L, ρL = 702.4 kg/m3
FLV = 15.26 ln(FLV) = 2.725 ρL − ρv ρv
Now permitted velocity, vperm = K
√
Where K =
+ C (ln F LV )2 + D (ln F LV )3 +
exp [ A + B ln F LV
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E(ln FLV )4 ]
64
In this equation, A, B, C, D and E are constants having the following values:-
A = -1.877478 B = -0.814580 C = -0.187074 D = -0.014523 E = -0.001015
Putting the values of FLV and these constants, K = 0.00292
Hence, vperm = K
D=
√
√
4 V π vpermρv
ρL − ρv ρv
= 0.03 m/s
= 4.86 m
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Now hv , related to the vapor velocity hv = 36” + hf = 12” +
1 diam 2
of feedline
1 diam 2
of feedline
L = h v + hf + h l
Now for nozzle diameter, umax =
100 √ρmix
, ft/s
umin =
60 , √ ρmix
ft/s
ρmix =
ρfeed = 578.19 kg/m3
umax = 4.16 ft/s = 1.27 m/s umin = 2.49 ft/s = 0.76 m/s
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Area of nozzle =
V olumetric f lowrate umin
=
0.0156 = 0.76
0.0205 m2
Dnozzle = 16.16 cm = 6.23 in ≈ 6.2 in
Hence, hv = 36 + 3.1 = 39.1 in hf = 12 + 3.1 = 15.1 in hl = 1 2( hv + hf ) = 27.1 in L = hv + hf + hl = 81.3 in = 2.06 m
Volume =
π D2 4
L = 38.23 m3
HEAT EXCHANGER HEAT EXCHANGER (B19) PROCESS DESIGN Design for number of tube, bundle diameter, shell diameter, tube side heat transfer coefficient (HTC), shell side HTC, Overall HTC and pressure drop for shell side and tube side (using Bell‘s Method). The values of all constants, tables and graphs have been taken from the book : Coulson Richardson’s Chemical Engineering Vol. 6 Chemical Engineering Design 4th edition. a) Properties of stream and HE layout specification Table : Properties of Hot Fluid Properties Values Stream Reactor outlet Inlet Temp Ti 170 Outlet Temp To 70 Mass Flow Rate 6626.39 Viscosity 1.28 x 10-4 1.86 Specific Heat Capacity, CP Density (vapor) 7.142 Thermal Conductivity 2.41 x 10-4 Table : Properties of Cold Fluid
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Unit ℃ ℃ kg/hr Pa.s kJ/kg-K kg/m3 W/m.K
67
Properties
Values
Unit
Stream Inlet Temp ti Outlet Temp to Mass Flow Rate Viscosity
Cooling Water 25 45 13413.12 8 x 10-4
℃ ℃ kg/hr Pa.s
Specific Heat Capacity, CP
4.178
kJ/kg.K
Density, ρ Thermal Conductivity, k
995 0.59
kg/m3 W/m.K
Step 1. Fluid Allocation : Shell side ( vapor) : Reactor outlet stream Tube side (liquid) : Cooling Water From mass and energy balance, Shell side mass flow rate, ms = 1.84 kg/s Tube side mass flow rate, mt = 3.72 kg/s Heat duty, Q = 311.33 kW
Step 2. LMTD Assuming counter current flow in a 1 shell 2 tube heat exchanger LMTD =
R=
∆T 1−∆T 2 1 ln ∆T ∆T 2
= 78.30 °C
(T i−T o) =5 (to−ti)
(to−ti) S = (T −t ) i i
= 0.14
From graph, FT = 0.965
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68
ΔTm,true =
True LMTD = FT x LMTD = 75.56 °C
Assumed overall heat transfer coefficient, Uass = 66.70 W/m2.℃
Q Area Required = A =
Uass∆Tm,true
= 61.77 m2
Choose tubes of following dimensions : 19mm OD, 16mm ID, 6.096m length effective length of straight tubes = 6.096 - 2 x 0.025 = 6.046 m Surface Area of one tube = 0.36 m2 Number of tubes =
Area Required Surface Area of one tube
= 172
Triangular pitch arrangement for the tubes has been used
Step 3. Tube side velocity Using 1.25do triangular pitch and split-ring floating head type and 2 tube pass. 1
Bundle diameter, Db = do ×
N ( K t )n1 1
= 0.37 m
Shell inner diameter, Di = Db + 0.053 = 0.42 m ( Di = Ds ) Number of tubes per pass, n = 86
(3.14 ndi2) Total flow area =
4
= 1.73 x 10-2 m2
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Velocity of water in tubes, ut =
mt (ρ x total f low area)
= 0.21 m/s
Step 4. Tube side heat transfer coefficient Method 1 : hi =
4200(1.35+0.02t)ut0.8
= 1454.25 W/m2-K
di0.2
Method 2 :
ρvdi Re = μ = 4309.51 Pr = µ
Cp k
= 5.66
L/di = 377.875 jh = 0.004
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70
k
h = ( f )j RePr 0.33 ( µ ) i
di
h
−0.14
µw
µ is assumed to be 1. µw Hence, hi = 1126.62 W/m2.K The minimum value is selected from both the methods. So, hi = 1126.62 W/m2.K Step 5. Shell side heat transfer coefficient lb = baffle spacing = 0.4 x Di = 0.17 m Tube pitch = pt = 2.38 x 10-2 m Cross flow area (As) =
(pt−do)lbDi = 1.41 x 10-2 m2 pt
ms Mass Velocity (Gs) = A = 130.12 kg /s.m2 s 1.10(pt2 – 0.917do2) Equivalent diameter, de =
Re =
do
= 1.34 x 10-2 m
Gsde μ = 137142.85
Pr = µ Cp k = 9.87
jh = 3.1 x 10-3
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71
k
f 0.33 2 hoc = ( do )j hRePr = 115.71 W/m -K
where hoc is the heat transfer coefficient calculated for cross-slow over an ideal tube bank, with no leakage and bypassing. Baffle cut, Bc = 25 % (assumed) Hb = height from the baffle chord to the top of the tube bundle Db = - D (0.5-B ) = 7.86 x 10-2 m 2
s
c
Ncv = the number of constrictions, tube rows, encountered in the cross-flow section Db−2Hb = 0.87p = 10.17 = 11 ( next integral value) t
Fn = tube row correction factor = 0.99
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72
Bundle cut, B =
Hb Db = 0.21
Ra’ = ratio of the bundle cross-sectional area in the window zone to the total bundle cross-sectional area = 0.14 Ra (at baffle cut) = 0.18
Nw = number of tubes in a window zone = R a’ x N = t 24.08 Rw = ratio of number of tubes in window zone to the total number in the bundle 2Nw = N = 0.28 t
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73
Nc = number of tubes in a cross-flow zone = Nt - 2Nw = 123.84 = 124 Fw = window correction factor = 1.08
Ab = clearance area between the bundle and the shell = lb(Ds-Db) = 8.91 x 10-3 m2 Ns = Number of sealing strips =3 Fb = bypass correction factor = exp (-
A
s 2/3 α Ab (1-( 2N ) )) = 0.87 N cv s
ct = diametrical tube-to-baffle clearance = 0.8 mm cs = baffle-to-shell clearance = 1.6 mm
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θb = angle subtended by the baffle chord = 2.1 rads Atb = tube to baffle clearance area, per baffle =
3.14ctdo(Nt−Nw) = 7.06 x 10-3 m2 2
Asb = shell to baffle clearance area, per baffle =
csDs(2x3.14−θb) = 1.41 x 10-3 m2 2
AL = Total leakage area = Atb + Asb = 8.47 x 10-3 m2 AL/As = 0.59 m2 βL = 0.37
FL = leakage correction factor = 1- β L (
Atb+2Asb AL
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) = 0.57
75
hs = hocFnFwFbFL = 61.31 W/m2-K Step 5: Overall coefficient
doln do 1 U
= h1o +
1 hod
+
di
2kw
+
do 1 di hid
+ ddo 1h
i i
U= 55.97 W/m2 oC where hod and hid are outer and inner dirt factors respectively. Error is less than 30 % , so the initial guess of overall heat transfer is current. Step 6: Pressure drop Shell side pressure drop jf = 4.5 x 10-2 ΔPi = pressure drop calculated for an ideal tube bank = F ’ = bypass correction factor for pressure drop = exp (-
8jf Ncvρus2 = 4342.03 Pa 2
α
Ab As
b
(1-( 2Ns )1/3)) Ncv
where ( α = 4) for Re > 100 Fb’ = 0.67 Ab/As = 0.63 βL′ = 0.6 FL’ = leakage factor for pressure drop = 1- β L ′
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(
Atb+2Asb AL
) = 0.30
76
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77
ΔPc = pressure drop in a cross − f low zone between the baffle tips, corrected for bypassing and leakage = ΔP i F b ′ F L ′ =
3.14Ds2Ra Aw = 4
-
868.03 Pa
3.14Nwdo2 = 1.82 x 10-2 m2 4
Nwv = number of restrictions for cross-flow in window zone, approximately equal to the
H number of tube rows = 0.87bp = 3.80 = 4 (round-off to next bigger integer) t uw = the velocity in the window zone, based on the window area less the area occupied by the tubes Aw =
ms = 14.18 m/s (Aw ρ)
uz = the geometric mean velocity = √uwus = 16.08 m/s ΔPw =
FL′(2 + 0.6Nwv)ρuz2/2
= 1186.98 Pa (Nwv +Ncv )
ΔPe = end zone pressure drop = ΔP i
Nb = number of baffles =
ef fective length lb
N cv
F ’ = 3971.20 Pa b
1 = 35.94 = 36
total shell side pressure drop = 2 ΔPe + (Nb − 1)ΔPe + Nb ΔPw = 6992.05 Pa
Tube side pressure drop Np = Number of tube passes = 2 jf = 6 x 10-3
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78
L
𝞓P = Np [8j ( )( t
f di
µ −m
)
+ 2.5]
µw
ρu2t 2
µ is equal to 1 ( assumed) µw 𝞓Pt = 963.03 Pa
MECHANICAL DESIGN OF REACTOR
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79
Data from process design: Shell inside diameter, Di = 5 m Column Parameters: Considering tray spacing = 0.45 m Height of shell = 7.5 m Operating pressure, P = 1 bars Design pressure = 105 kPa Selection of Materials: IS : 2002-1962 – Grade 2B , with double – welded butt joints (Ref : Table A – 1 , Pg 261, BCB) Calculation of Thickness: Thickness will be calculated using equation for low pressure vessel as pressure < 20 MN/m2 which assumes that the thickness, t, and internal diameter, Di ,ratio doesn’t exceed 0.25, which will be checked later .
PDi
t = 2f J −P f = 98.1 MN/m2 (Ref: Appendix A, Pg 261, BCB) J=1 Hence, t = 0.00267 m Corrosion allowance = 0.003 m So,Thickness standard = 0.007 m Do=Di + 2t = 5.014 m
Thickness of head: Torispherical Assuming Ri = Do= 5.014 m ri = 0.3, Do = 5.014 m
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80
ho = Ro – (( Ro – 0.5Do)(Ro + 0.5Do – 2ro))0.5 = 0.84 m Do2/4R o= 1.235 m (Doro/2)0.5 = 0.86 m Ho is least effective external height of head (hE) = 0.84 m J=1 t/Do =
P 2f J
C = 0.00177C
hE/Do = 0.169 From table, t/Do =0.0017 C = 3.21 t/Do = 0.0017 t = 0.0088 m Therefore, thickness = 12 mm t/Do ratio is less than 0.25. Hence, assumption is valid Hence, thickness = 12 mm Blank diameter = 5.41 m Height of flange = Sf =40 mm Stress calculation: Thickness = 0.0026 m Corrosion allowance = 0.003 m Top + bottom disengaging space = 1 m Insulation = 75mm asbestos Maximum wind velocity expected = 140 km/h Weight of each head = (πDb2ht sρ g)/4 = 129626.54 kg Axial stress due to pressure: σ zp =
PDi2
= 49.02 MN/m2
4t(Di+t)
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81
Axial stress due to dead loads: Wa = Wt. of shell for X meters length = (π D t X ϒins) N Ws
σ zs = Π D = ϒs X x 10-6 MN/m2 = 63563 kg t Assuming constant shell thickness, Wi = weight of insulation for a weight X meters = π Dins tins ϒins X x 10-6 MN/m2 = 49877.98 kg σ zi = Wi/ πDot = (tins ϒins X) /t = 1.18 MN/m2 σ zl = Wl/ πDt =54.03 MN/m2
Weight of ZnO = 403680 kg Hence weight of attachments is the sum of the three weights above (Wa)=413917 kg σ za = Wa/ πDot = 9.8 MN/ m2 Net stress, σ zw = σ za + σ zl + σ zs + σ zi = 11.34 MN/ m2 Stress due to wind loads: Wind pressures, Pw = 0.05 Vw2 = 980 N/m2 From table 9.1 BCB, maximum wind pressures is about 1000 N/m2 Hence Pw = 1000 N/m2 will be used K1 = 0.7 Calculation of K2 W = W s+ W i + W l + W a = 110.043 kN T = 6.35 x 10-5 (H/D)1.5(W/t)0.5 = 1.6 s > 0.5 s Hence K2 = 2 As height of column < 20 m, so wind load will not vary along the height of the column Pw = K1K2P1h1Do = 52.95 kN Bending moment
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82
Mw = PwH/2 = 197.06 kJ Resulting bending stress 4Mw
σ zsw = Πt(D +t)D =3.74 MN/m2 i i Design of skirt support: Important considerations Tensile stress in the skirt will be maximum when the dead weight is minimum i.e. the shell is just erected and the shell is empty without any internal attachment.The compression stress is yet to be determined when the vessel is filled up water for hydraulic test. Maximum wind load may be expected at any and this factor is always considered. Period of vibration: Minimum weight of vessels with two heads and a shell Wmain = π (Di + t) t(H-4) ϒs + 2 Wh Di = 1.73 m Wmin = 322.816 kN Wmax = 270.866 kN Tmin = 6.35 x 10-5 (H/D)1.5(Wmin/ta)0.5 = 2.42 > 0.5 Hence K2 = 2 (a coefficient to determine wind load) Wind load: The minimum wind load K, Pw = K1K2P1HDo Hence, Pw,min = 80.75 kN Pw,,max = 83.14 kN Wind Moment: Minimum wind moment Mw(min) = Pw(min) x H/2 = 302.07 kJ Maximum wind moment
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83
Mw(max) = Pw(max) x H/2 = 311.57 kJ As skirt thickness is assumed as I, So, Di = Do = 5.014 m σ zwm (min) = 4Mw(min)/ πD2t = 0.098/t MN/m2 σ zwm (max) = 4Mw(max)/ πD2t = 0.1225/t MN/m2 Tensile strength: Maximum tensile strength without any eccentric loads σ z,tensile = σ zwm,min - σ zw,min Substituting σz = f x J t = 0.042 mm Compression load σ z,max = σ zwm (max) + σ zw(max) Substituting Az(compressive) = 0.125 E (t/Do) t = 42 mm As per IS : 2825-1969 So, thickness of skirt plate = 42 mm
Design of skirt plate: Maximum compressive stress between bearing plate and foundation is: I = outer radius of bearing – outer bearing of skirt σ c = Wmax/A + Mw/z =0.23865/(2.71I - I2) + 0.277228/(2.71 - I)2I
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84
Assuming σ c= 2.74 MN/m2 I = 0.023 m So, I = 100 mm = width of bearing plate Thickness of bearing plate: Tbp = I(3 σ c/f)0.5 = 32 mm (approx.) So, a bearing plate of 32 mm thickness is used Stability factor: R = Do + 2I J = WminR/Mw = 3.44 (Skirt need not be anchored) Thickness of gusset plate = 0.014 m Number of gussets = 110 N x Pbolt = 0.322 Ar x n = 0.0067 Ar = 67 mm2 number of bolts = 101.22 = 108 bolts
HEAT EXCHANGER : Heat exchanger is assumed to be a cylindrical vessel under internal pressure. SHELL THICKNESS CALCULATION: Operating pressure = 1 bar Design pressure (P ) = 1.05 bar d
[From process Design] Material of construction: IS 1570-1961 15Cr9oMo55
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85
Design Temperature (T ) = 250 C o
o
f = 118 MN/m = 118 x 106 N/m
2
2
t=
pDi 2f J +p
[Ref: Eq. 3.3.19, BCB, 5 ED.]
Weld joint efficiency factor, J = 0.85
[Ref: Art. 2.8, Pg 20 BCB, 5 ED.]
t = 0.21 mm Corrosion allowance = 2mm Thus, thickness (t) = t + C.A = 2.21 mm = 5 mm (Std) [t/D < 0.25 thus assumption is valid] i
Thus, Outer diameter, Do = Di + 2t = 0.043 m
HEAD DESIGN: For the cylindrical design of exchanger, we have chosen Torispherical head because pressure is in range 0.1 - 1.5 MN/m . 2
D = 0.43m J=1
Taking head specifications as:
Ri = Do = Ro ri = 0.06 D = 0.025 m o
Sf = 40mm ho = Ro − [(Ro −
Do )(Ro 2
+
Do 2
− 2ro)]
0.5
[Ref: Eq. 4.2.22, BCB, 5 ED.]
ho 0.072 m D2o/4ro = 0.107 m
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86
Doro/2 = 0.074 m
Out of these three quantities calculated above, ho is the least. Therefore, ho = 0.107 m
he/Do = 0.169 J=1 p/2fJ = 0.000444
Trying out various values of t/Do from Table 4.1
t/Do = 0.0015 t = 0.00064 m = 0.64 mm
NOZZLES AND BRANCH PIPES:
Construction of nozzles: Shell nozzle: Material construction: Same as that of shell. f = 118 MN/m = 118 x 106 N/m 2
2
Shell wall thickness, ts = 0.05 m Corrosion Allowance (C) = 0.002 m dnozzle = 0.218 m
tr =
pDo = 0.00019 m 2f J +p
Area to be compensated (A) = (d + 2c )tr = 0.000042 m2
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87
Area available from shell (As) = (d + 2c)(ts – tr – C ) = 0.0106 m2 Area available from nozzle for reinforcement
tr′ =
pdo = 0.00011 m 2f J +p
H1 = [(d + 2C)(tn - C)]0.5 = 0.055 m An = 2H1(tn - tr’ - C) = 0.0015 m2
Area remaining to be compensated Area = A – (As + An) = -0.012 m2
Hence, no ring pad required.
Design of flange for opening:
Taking IS: 2004-1962 Class2: y = 25.5 MN/ m2
[Ref. Table 7.1, page 103 BCB, 5 ED.]
m = 2.75 Allowable Stress for Flange = 100MN/m2 Allowable stress of bolting material = 138 MN/m2 (Bolting material – 5% CRMO Steel) p = 1.05 MN/m2 d0 y−pm
=(
di
0.5
y−p(m+1))
= 0.85
Let di of gasket = 0.44 m do = 0.377 m Minimum gasket width (N) = (do-di)/2 = 0.011 m
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do (calculated) = di+ 2N = 0.46 m Basic Gasket seating width (bo) = N/2 = 0.0055 m Diameter at location of gasket load reaction G = di + N = 0.45 m
LOAD DUE TO DESIGN PRESSURE:
H = πd2p/4 = 1.697 MN
Load to keep joint tight under operation: Hp = πG(2b)mp = 1.675 MN
Total operating load: Wo = H + Hp = 1.677 MN Load to seal gasket under bolting up conditions, Wg = πGby = 0.19 MN So, Wo is controlling load. Minimum bolting area, Where, Ao = Am = Wo/So = 0.0057 m2 go = Shell thickness = 5 mm gi = 1.415 go = 7.075 mm C = ID + 2(gi + R) ID = B = 0.899 m
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M 30 x 2 is most suited (because difference in c is minimum) and hence selected.
Bolt diameter = 0.03 m No. of bolts = 12 Bolt circle diameter = 1.0068 m Flange outside diameter (A) = 1.0068 + 0.03 + 0.02 = 1.057 m Check of gasket width:
AoSo = 56.38 < 2y πGN
So, condition is satisfied.
FLANGE MOMENT COMPUTATION:
a) Operating Condition
Wo = W1 + W2 + W3 W1 = πB p/4 = 1.527 MN 2
W2 = H – W1 = 0.152 MN
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W3 = Wo – H = Hp = 1.67 MN
Selected lap joint flange a1= (C – B)/2 = 0.28 m a3 = (C – G)/2 = 0.27 m a2 = (a1 + a3)/2 = 0.28 m Mo = W1a1 + W2a2 + W3a3 0.4657 MJ Mo = Total flange moment
Bolting up condition:
Mg = Wa3 = 0.362 MJ M g < Mo Hence, Mo is controlling.
So, M = 0.46 MJ Calculation for flange thickness:
K = A/B = 2.45 Y = 1.
[Ref: figure 7.6, Pg 115, BCB, 5 ED.]
Assuming Cf = 0.1; t2 = (MCfY)/(BST) = 0.0025 t = 0.05 m Bs = πC/n = 0.2634 m Bolt pitch correction factor, Cf = [Bs/(2d+t)]0.5 = 0.15 Corrected flange thickness = t.Cf0.5 = 0.0767 m So, Final Flange Thickness = 85 mm
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MECHANICAL DESIGN OF DISTILLATION COLUMN
Data from process design: Shell inside diameter, Di = 1.73 m Column Parameters: Considering tray spacing = 0.45 m Number of trays = 31 Therefore 31 trays at 0.5 m spacing, and top and bottom engaging space 1 m each Bottom Separator Space = 2.75 m Length of column including skirt height = 18.45 m Operating pressure, P = 19 bars = 1900 kPa Design pressure = 199.5 kPa Selection of Materials: IS : 2002-1962 – Grade 2B , with double – welded butt joints (Ref : Table A – 1 , Pg 261, BCB) Calculation of Thickness: Thickness will be calculated using equation for low pressure vessel as pressure < 20 MN/m2 which assumes that the thickness, t, and internal diameter, Di ,ratio doesn’t exceed 0.25, which will be checked later .
t=
PDi 2f J −P
f = 98.1 MN/m2 (Ref: Appendix A, Pg 261, BCB) J=1 Hence, t = 0.0177 m Corrosion allowance = 0.003 m So,Thickness = 0.025 m Do=Di + t = 1.755 m
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Thickness of head: Torispherical Assuming Ri = Do= 1.78 m ri = 0.1038, Do = 1.78 m ho = Ro – (( Ro – 0.5Do)(Ro + 0.5Do – 2ro))0.5 = 0.301 m Do2/4R o= 1.4 m (Doro/2)0.5 = 0.3 m Ho is least effective external height of head (hE) = 0.3 m J=1 t/Do =
P 2f J
C = 0.01016C
hE/Do = 0.015 From table, t/Do =0.015 C = 1.605 t/Do = 0.015 t = 0.0267 m Therefore, thickness = 32 mm t/Do ratio is less than 0.25. Hence, assumption is valid Hence, thickness = 32 mm Height of flange = Sf =40 mm Stress calculation: Thickness = 0.017 m Corrosion allowance = 0.003 m Tray spacing = 0.5 m Top disengaging space = 1 m
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Bottom separator space = 2.75 m Weir height = 50 mm for all trays Downcomer clearance = 25 mm for all trays Insulation = 75mm asbestos Accessories: 1 caged ladder Maximum wind velocity expected = 140 km/h Tray loading = 25 lb/ft2 Weight of each head = (πDb2ht sρ g)/4 = 5799.63 kg Axial stress due to pressure: σ zp =
PDi2
= 48.55 MN/m2
4t(Di+t)
Axial stress due to dead loads: Wa = Wt. of shell for X meters length = (π D t X ϒins) N σ zs =
Ws Πt D
= ϒs X x 10-6 MN/m2 = 1.99 MN/m2
Assuming constant shell thickness, Wi = weight of insulation for a weight X meters = π Dins tins ϒins X x 10-6 MN/m2 = 43007 kg σ zi = Wi/ πDot = (tins ϒins X) /t = 0.439 MN/m2 Number of trays= 25 Weight of liquid, supported, Wl = (π/4t)Do2(0.05)(9.81) n x 10-6 MN = 5440 kg σ zl = Wl/ πDt =54.03 MN/m2
Weight of trays = ( πD2/4) x (1) x n x 10-3 MN = 72534 kg Hence weight of attachments is the sum of the three weights above (Wa)=86768 kg
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σ za = Wa/ πDot = 0.89 MN/ m2 Net stress, σ zw = σ za + σ zl + σ zs + σ zi = 0.288 MN/ m2 Stress due to wind loads: Wind pressures, Pw = 0.05 Vw2 = 980 N/m2 From table 9.1 BCB, maximum wind pressures is about 1000 N/m2 Hence Pw = 1000 N/m3 will be used K1 = 0.7 Calculation of K2 W = W s+ W i + W l + W a = 110.043 kN T = 6.35 x 10-5 (H/D)1.5(W/t)0.5 = 9.3 s > 0.5 s Hence K2 = 2 As height of column < 20 m, so wind load will not vary along the height of the column Pw = K1K2P1h1Do = 45.95 kN Bending moment Mw = PwH/2 = 424.06 kJ Resulting bending stress 4Mw
σ zsw = Πt(D +t)D = 9.87 MN/m2 i i Design of skirt support: Important considerations Tensile stress in the skirt will be maximum when the dead weight is minimum i.e. the shell is just erected and the shell is empty without any internal attachment.The compression stress is yet to be determined when the vessel is filled up water for hydraulic test. Maximum wind load may be expected at any and this factor is always considered. Period of vibration: Minimum weight of vessels with two heads and a shell Wmain = π (Di + t) t(H-4) ϒs + 2 Wh
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Di = 1.73 m
Wmin = 207.28 kN Wmax = 368.642 kN Tmin = 6.35 x 10-5 (H/D)1.5(Wmin/ta)0.5 = 9.9 > 0.5 Hence K2 = 2 (a coefficient to determine wind load) Wind load: The minimum wind load K, Pw = K1K2P1HDo For minimum weight condition, Do = 2.615 m For maximum weight condition, Do = 2.765 m Hence, Pw,min = 55.45 kN Pw,,max = 60.02 kN Wind Moment: Minimum wind moment Mw(min) = Pw(min) x H/2 = 55.07 kJ Maximum wind moment Mw(max) = Pw(max) x H/2 = 60.57 kJ As skirt thickness is assumed as I, So, Di = Do = 1.73 m σ zwm (min) = 4Mw(min)/ πD2t = 0.207/t MN/m2 σ zwm (max) = 4Mw(max)/ πD2t = 0.095/t MN/m2 Tensile strength: Maximum tensile strength without any eccentric loads
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σ z,tensile = σ zwm,min - σ zw,min Substituting σ z= f x J t = 0.0301 mm Compression load σ z,max = σ zwm (max) + σ zw(max) Substituting Az(compressive) = 0.125 E (t/Do) t = 34 mm As per IS : 2825-1969 So, thickness of skirt plate = 37mm
Design of skirt plate: Maximum compressive stress between bearing plate and foundation is: I = outer radius of bearing – outer bearing of skirt σ c = Wmax/A + Mw/z =0.23865/(2.71I - I2) + 0.277228/(2.71 - I)2I Assuming σ c= 25.6 MN/m2 I = 0.023 m So, I = 100 mm = width of bearing plate Thickness of bearing plate: Tbp = I(3 σ c/f)0.5 = 88 mm (approx.)
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So, a bearing plate of 88 mm thickness is used Stability factor: R = Do + 2I J = WminR/Mw = 0.36
Thickness of gusset plate = 0.043 m Number of gussets = 54 N x Pbolt = 0.207 Ar x n = 0.0043 Ar = 63 mm2 number of bolts = 69
3.4.d Design of auxiliary process equipment Pump Design Following data has been collected from Aspen plus software, for designing the pump system : Suction Pressure, P1 = 1 bar Discharge Pressure, P2= 30 bar Inlet fluid temperature = 32.75 oC Outlet fluid temperature = 33.51 oC Efficiency of the pump, η = 62.91 % Inlet fluid density = 755.164 kg/m3 Outlet fluid density = 755.081 kg/m3 Average fluid density, ρavg = 755.21 kg/m3 Volumetric flow rate of the fluid, v’ = 49.458 m3/hr.
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Head loss in the pump =
Power Intake =
(P 2−P 1)v′ = 3600η
P 2−P 1 9.81ρ avg.
38446.72 W
3.4.e Major engineering problems of the plant with their possible remedies. Problem — Carelessness or Unsafe Practices. In manufacturing, it is crucial that you and your team not grow complacent when it comes to workplace safety. In almost no other work environment is the risk of workplace accidents so high. The top three causes of injury and death in manufacturing are falling, being struck by an object, and electrocution — all preventable, if you know what to look for and take the proper prevention steps. The Fix — Constant Training and Inspections. Your workers should know safety procedures ranging from regular inspections to emergency response. They should be trained to spot anything out of the ordinary. Additionally, all of your equipment should be professionally inspected on a regular basis. Problem — Unrealistic Goals. It’s easy to be overly optimistic, especially if you believe you can win manufacturing business with an aggressive timeline. But many times, you’re setting yourself
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up to fail. Straining your workforce can actually be counterproductive by hurting morale and increasing the chances for mistakes. Unrealistic goals can set you up for bad business. The Fix — Detailed Project Management. In manufacturing, you must keep close track of your resources and manpower. Many facilities are migrating to different types of management software that allow you to see more than simply when your workers are clocking in and out. You can see how much time is needed for each task and plan future projects better. The result is a more consistent workload with realistic expectations. Problem — Planning Without Input. Planning a project takes collaboration and input from all involved. Failing to get feedback from your workers can result in heavy workloads that slow productivity. Further, if you fail to manage customer expectations, you could lose future business. The Fix — Planning Task Force. Your workers know better than anyone what can be done in a given amount of time and the best way to accomplish a task. Assign workers with varying expertise to give you feedback. Consult with them while you are still in the planning stage so that you can set more accurate expectations for your customers and to ensure that all needs can be met.
3.5. Material Storage and Handling Facilities Urea Physical state Vapor Density: 2.07 (Air = 1) Specific Gravity: 1.323 (Water = 1) Melting Point: 132.7°C (270.9°F) Saline Molecular Weight: 60.06 g/mol Water/Oil Dist. Coeff.: The product is more soluble in water;
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Solubility: Easily soluble in cold water, hot water. Physical state and appearance: Solid. (Crystals solid.) Odor: Almost odorless; May gradually develop slight odor of ammonia, especially in presence of moisture.
Storage and Handling Storage: Keep container(s) tightly closed. Use and store this material in cool, dry, well ventilated areas. Sore only in approved containers. Keep away from any incompatible material. Protect container(s) against physical damage.
Handling: The use of appropriate respiratory protection is advised when concentrations exceed any established exposure limits. Wash thoroughly after handling. Wash contaminated clothing or shoes. Use good personal hygiene practices. If used for the manufacture of feeds for livestock, mix thoroughly by making a pre-blend with one of the ingredients, then adding and mixing the preblend with all other ingredients.
Fire Fighting Measures Flammable Properties: Feed Urea 46% is non-flammable Flash Point-Not applicable OSHA Flammability Class-Not applicable LEL/UEL-Not applicable Autoignition Temperature-Not applicable
Unusual Fire & Explosion Hazards: Material will not burn. Undergoes thermal decomposition at elevated temperatures to produce solid cyanuric acid and release toxic and combustible gases (ammonia, carbon dioxide, and oxides of nitrogen). May explode when mixed with certain strong reducing substances (hypochlorites) - forms nitrogen trichloride which explodes spontaneously in air.
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Extinguishing Media: Use extinguishing agent suitable for type of surrounding fire. Fire Fighting Instructions: Positive pressure, self-contained breathing apparatus is required for all fire fighting activities involving hazardous materials. Full structural firefighting(bunker) gear is the minimum acceptable attire. The need for proximity, entry, flashover and/or special chemical protective clothing needs to be determined for each incident by a competent fire fighting safety professional. Water used for fire suppression and cooling may become contaminated. Discharge to sewer system(s) or the environment may be restricted, requiring containment and proper disposal of water.
First Aid Measures: Eye: If irritation or redness develops, move victim away from exposure and into fresh air. Flush eyes with clean water. If symptoms persist, seek medical attention. Skin: Remove contaminated shoes and clothing and cleanse affected area(s) thoroughly by washing with mild soap and water. If irritation or redness develops and persists, seek medical attention. Inhalation (Breathing): If respiratory symptoms develop, move victim away from source of exposure and into fresh air. If symptoms persist, seek medical attention. If victim is not breathing, clear airway and immediately begin artificial respiration. If breathing difficulties develop, oxygen should be administered by qualified personnel. Seek immediate medical attention. Ingestion (Swallowing): First aid is not normally required; however, if swallowed and symptoms develop, seek medical attention. Animal Antidote and Emergency Treatment: In animals, the cold water-acetic acid treatment may be useful. The adult cow is given 19 - 38 liters cold water and 3.8 liters of 5% acetic acid (vinegar) orally. This treatment limits absorption of ammonia from the rumen by diluting the rumen contents and slowing the rate of hydrolysis of urea by decreasing rumen pH and temperature. This treatment also promotes urine flow that, if maintained by fluid therapy, may assure recovery from urea toxicity. Gaseous or fluid bloat should be relieved before pumping water into the rumen. Consult your veterinarian immediately.
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Accidental Release Measures Urea is a feed ingredient and crop nutrient, however, large spills can harm or kill vegetation. ● Stay upwind and away from spill (dust hazard). ● Wear appropriate protective equipment, including respiratory protection, as conditions warrant ● Prevent spilled material from entering sewers, storm drains, other unauthorized treatment drainage systems, and natural waterways. ● Notify appropriate federal, state, and local agencies as may be required ● Minimize dust generation. ● Sweep up and package appropriately for disposal
Exposure Control/Personal Protection Engineering Controls: If current ventilation practices are not adequate to maintain airborne concentrations below the established exposure limits (see Section 2), additional ventilation or exhaust systems may be required. Respiratory: A NIOSH approved air purifying respirator with a type 95 (R or P) particulate filter may be used under conditions where airborne concentrations are expected to exceed exposure limits. Protection provided by air purifying respirators is limited (see manufacturer's respirator selection guide). Use a positive pressure air supplied respirator if there is potential for uncontrolled release, exposure levels are not known, or any other circumstances where air purifying respirators may not provide adequate protection. A respiratory protection program that meets OSHA's 29 CFR 1910.134 and ANSI Z88.2 requirements must be followed if workplace conditions warrant a respirator. Skin: The use of cloth or leather work gloves is advised to prevent skin contact, possible irritation and absorption (see glove manufacturer literature for information on permeability).
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Eye/Face: Approved eye protection to safeguard against potential eye contact, irritation, or injury is recommended. Other PPE: A source of clean water should be available in the work area for flushing eyes and skin. Impervious clothing should be worn as needed.
Stability and Reactivity Chemical Stability: Stable under normal conditions of storage and handling. Conditions to Avoid: Urea forms an explosive salt with nitric acid. Reacts violently with gallium perchlorate. Incompatible Materials: Not applicable in feed mill situation. Corrosivity: May be slightly corrosive to steel, aluminum, zinc, and copper. Hazardous Decomposition Products: Heating above 270.9°F (132.7°C) (decomposes to biuret, ammonia, cyanuric acid, and nitrogen oxides. Hazardous Polymerization: Will not occur.
Potential Health Effects Eye: Contact may cause mild eye irritation including stinging, watering and redness. Skin: Contact may cause mild irritation including redness and a burning sensation. No harmful effects from skin absorption are expected. Inhalation (Breathing): No information available. Studies by other exposure routes suggest a low degree of toxicity by inhalation. Urea dust may cause mild irritation of the nose, throat and respiratory tract. Ingestion (Swallowing): No harmful effect report by ingestion. Swallowing may cause irritation of the digestive tract. Signs and Symptoms: Effects of overexposure may include irritation of the nose, throat, respiratory and digestive tract, nausea, vomiting, coughing, and transient disorientation. Cancer: No carcinogenic effects in humans reported in the literature examined.
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Developmental: Inadequate data available to evaluate the developmental effects of this material. Other Comments: May be harmful to livestock if ingested without adequate mixing. If used for the manufacture of feeds for livestock, mix thoroughly by making a preblend with one of the ingredients, then adding and mixing the pre-blend with all other ingredients. Equivalent protein from Urea should not exceed 1/3 of the protein in the mixture.
Methanol Physical Data
Physical State: Liquid Appearance: Clear, Colorless Odor: Slight Alcohol Odor Molecular Wt.: 32.04 Boiling Point (760 mm Hg): 64.5°C Flash Point: 11 °C Auto Ignition Temp: 385 °C (NFPA 1978) Vapor Pressure @ 200 °C : 12.8 kPa Vapor Density: 1.11 (Air = 1) Viscosity: 0.55 cP (20 °C) % Volatile / Volume: 100.0 Freezing / Melting Pt.: -98 °C (-144 F) Water Solubility: Complete Soluble in: Water, Ethanol, Ether, Acetone, and Chloroform Partition Coefficient n-octanol/water: -0.82 / -0.66 Evaporation Rate: (BuAc=1) 5.9 (Ether = 1)5.3 Specific Gravity: 0.791 – 0.793 Saturation Concentration: 166 g/m
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Storage & Handling
Handling ● Wash hands thoroughly after handling. In the event of exposure, remove contaminated clothing and wash before reuse. ● Containers should be grounded and bonded when transferring material in order to avoid static sparks. ● Do not breathe vapor, mist or gas. Do not get in eyes, skin or clothing. ● Use non-sparking type tools and equipment,including explosion-proof ventilation. ● Empty containers retain product residue (liquid and/or vapor) and can be dangerous. ● Do not pressurize, cut, weld, braze, solder, drill, grind or expose such containers to heat, sparks,flame, static electricity or other sources of ignition. ● Keep container tightly closed.
Storage ● Keep away from heat, sparks, flames (all sources of ignition). Keep away from oxidizers,acids and bases. ● Store in a cool, dry, well-ventilated area away from incompatible substances. Outside or detached storage is recommended. ● Tanks must be grounded and vented and have vapor emission controls including floating roofs, inert gas blanketing to prevent the formation of explosive mixtures and pressure vacuum relief valves to control tank pressures. Tanks should be of welded construction and should also be diked. ● Do not store in aluminum or lead containers.(Anhydrous methanol is non-corrosive to most metals at ambient temperatures except lead and magnesium. ●
Coatings of copper and its alloys, zinc, or aluminum are unsuitable for storage as they are attacked slowly. Mild Steel is the recommended construction material for tanks.)
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● Plastics may be used for short-term storage, but not recommended for long-term use due to deterioration effects and the subsequent risk of contamination.
Fire Fighting Measures
Flash Point: 11°C Lower Explosive Limit: 6% (NFPA 1978) Upper Explosive Limit: 36% (NFPA 1978) Auto Ignition Temp.: 385°C NFPA 1978) Hazardous Combustion Products: Toxic gases and vapors; Oxides of Carbon and Formaldehyde. Extinguishing Media ● Small fires: Use dry chemical, carbon dioxide, water spray or alcohol resistant foam. Use water sprays to cool fire-exposed containers. ● Large fires: Use water spray, water fog or alcohol-resistant foam. Special Protective Equipment for Firefighters ● Firefighters must wear full face, positive pressure self-contained breathing apparatus, MSHA/ NIOSH (approved or equivalent), and full protective gear. ● Protective firefighting structural clothing may not offer complete protection from a methanol fire if there is liquid methanol or vapor levels above the threshold limit value (TLV). Use of HAZMAT suits are recommended.
Important Information Methanol burns with a clean, clear flame, which is almost invisible in daylight. Containers may build up pressure if exposed to heat and/or fire. Cool tanks / drums with water spray and remove them to safety. Fire fighting water should be contained if possible, as it is toxic and can cause environmental damage. Water runoff can cause environmental damage. Vapors can travel to a source of ignition and flash back. Material is lighter than water, and so a fire can be spread by
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the use of water. During a fire, irritating and highly toxic gases may be generated by thermal decomposition or combustion.Responders should stay upwind.
Accidental Release Measures Procedure ● Wear appropriate personal protective equipment as specified. ● Stay upwind. ● Ventilate area of leak or spill and isolate hazard area. ● Eliminate all sources of ignition. ● Keep unnecessary and unprotected personnel from entering the hazard zone. ● Contain and recover liquid where possible or dilute with water or use alcohol-resistant foam to reduce fire hazard. Collect liquid in an appropriate container or absorb with an inert material (e.g. vermiculite, dry sand, earth) and place in a chemical waste container. Do not use combustible materials such as sawdust. ● Use non-sparking tools and equipment. ● Do not flush to sewer and prevent from entering confined spaces. ● US regulations (CERCLA) require reporting spills and releases to soil, water and air in excess of reportable quantities.
Waste Disposal ● Recycling is the recommended disposal method. ● Incineration should only be performed using a legally approved incinerator fitted with emission controls. ● Methanol wastes are not suitable for underground injection. ● Biological treatment may be used for dilute aqueous waste methanol.
Exposure Controls / Personal Protection
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Engineering Controls: Use explosion-proof ventilation equipment. Use adequate general or local exhaust ventilation to keep airborne concentrations below the permissible exposure limits. Use only under a chemical fume hood. Facilities storing or utilizing this material should be equipped with an eyewash facility and a safety shower. Personal Protective Equipment ● Respiratory Protection: A respiratory protection program that meets OSHA’s 29 CFR 1910.134) and ANSI Z88.2 requirements or European Standard EN 149 must be followed whenever workplace conditions warrant a respirator use. ● Eye Protection: Use face shield and chemical flash goggles. ● Skin Protection: Rubber (Butyl or Nitrile) or neoprene gloves and additional protection including impervious boots, aprons, or coveralls as needed in areas of unusual exposure. PPE must not be considered a long-term solution to exposure control. PPE usage must be accompanied by employer programs to properly select, maintain, clean, fit and use. Consult a competent industrial hygiene resource to determine hazard potential and/or the PPE manufacturers to ensure adequate protection.
Stability & Reactivity Chemical Stability: Stable under normal temperatures and pressures. Conditions to Avoid: High temperatures, incompatible materials, ignition sources, oxidizers. Incompatible Materials: Avoid contact with strong oxidizers, strong mineral or organic acids and strong bases. Contact with these materials may cause a violent or explosive reaction. May be corrosive to lead, aluminum, magnesium and platinum. Hazardous Decomposition Products: Carbon monoxide, irritating and toxic fumes and gases, carbon dioxide, formaldehyde.
Hazards Identification Emergency Overview
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Vapor harmful. May be fatal or cause blindness if swallowed. Harmful if inhaled or absorbed through the skin. Flammable liquid and vapor. Causes irritation to skin,eyes and respiratory tract. Affects central nervous system and liver.
Target Organs: Kidneys, heart, central nervous system, liver, eyes.
Potential Health Effects Inhalation:An irritant to the mucous membranes. Toxic effects exerted upon nervous system, particularly the optic nerve. Once absorbed into the body, it is very slowly eliminated. Symptoms of overexposure may include headache, drowsiness, nausea, vomiting, blurred vision, blindness, coma, and death. A person may get better but then worse up to 30 hours later.
Ingestion: Toxic. Symptoms similar to those for inhalation, but severity and speed of appearance may be greater. May be fatal or cause blindness. Usual fatal dose: 100 – 125 ml. May cause gastrointestinal irritation with nausea, vomiting and diarrhea. May cause central nervous system depression, characterized by excitement, followed by headache, dizziness, drowsiness and nausea. Advanced stages may cause collapse, unconsciousness, coma and possible death due to respiratory failure.
Skin Contact:Methyl Alcohol is a defatting agent and may cause skin to become dry and cracked. Skin absorption can occur in harmful amounts; symptoms may parallel inhalation exposure.
Eye Contact: Irritant, characterized by a burning sensation, redness, tearing, inflammation, possible corneal injury, painful sensitization to light. Continued exposure may cause lesions.
Chronic Exposure: Marked impairment of vision has been reported. Repeated or prolonged skin contact may cause dermatitis. Chronic exposure may cause reproductive disorders and teratogenic effects. Laboratory experiments have resulted in mutagenic effects.
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Aggravation of Pre-Existing Conditions: Persons with pre-existing skin disorders or eye problems or impaired liver or kidney function may be more susceptible to the effects of the substance.
Other Highly flammable. May build up Electrostatic charges: risk of ignition. Vapor-Air mixture is flammable / explosive within the explosion limits.
National Fire Protection Association (NFPA) 704 Hazard Identification Rating Health:1
Other
Rating System
Reactivity:0
0 = No Hazard
Flammability:3
1 = Slight Hazard
Special Hazards:None
2 = Moderate Hazard 3 = Serious Hazard 4 = Severe Haza
First Aid Measures
Eyes Immediately flush eyes with an ample amount of water for at least 15 minutes, occasionally lifting upper and lower eyelids. Get medical help immediately. Skin Immediately wash skin with lots of soap and water for at least 15 minutes while removing contaminated clothing and shoes. Get medical aid if irritation develops or persists. Inhalation
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Remove from exposure to fresh air immediately. If breathing is difficult, give oxygen if available. If breathing has ceased apply artificial respiration using oxygen and a suitable mechanical device such as a bag and a mask. Ingestion The ingestion of methanol is potentially life threatening. Onset of symptoms may be delayed for 18 to 24 hours after digestion. If the victim is conscious and medical help is not immediately available, give 2 to 4 cupfuls of milk or water. Do not induce vomiting! Transport victim to a medical facility immediately. Note to Physician Effects may be delayed. Ethanol may inhibit methanol metabolism.
DMC Physicochemical properties Boiling point: 90 °C Density: 1.07 g/cm3 (20 °C) Explosion limit: 4.22 - 12.87 %(V) Flash point: 16.7 °C Ignition Temperature: 458 °C Melting Point: 0.5 - 4.7 °C Vapor pressure: 53 hPa (20 °C) Solubility: 139 g/l
Hazard Identification: 1. Flammable liquid 2. Keep away from heat, spark, and flame. 3. Keep container closed. 4. Use with adequate ventilation.
First Aid Measures:
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Inhalation: Remove to flesh air. If not breathing, give artificial respiration. If breathing is difficult, give oxygen. Skin: Immediately flush skin with plenty of water for at least 15 minutes while removing contaminated clothing and shoes. Splashes in eyes: Immediately flush eyes with plenty of water for at least 15 minutes while removing contaminated clothing and shoes. Ingestion: Immediately flush mouth, get medical attention.
Fire Fighting Measures: Suitable extinguishing media: Water spray, Carbon dioxide, Dry chemical powder. Special exposure hazards in a fire: It emits smoke and irritating fumes. Special protective equipment for a fire: Use a positive-pressure, self-contained breathing apparatus and full protective clothing.
Accidental Release Measure: Personal precautions: Wear respirator, goggles, boots and gloves. Methods for cleaning up: Absorb spill with inert material (e.g., dry sand or earth), then place in a chemical waste containers using non sparking tools. Flush residual spill with copious amounts of water. For large spills, dike for later disposal. Other instructions: Consult with local, state and country officials.
Handling and Storage Handling: Avoid contact with eyes, skins, and clothing. Wash thoroughly after handling. Storage: Store in cool dry place. Keep package closed. Keep away from heat, spark, and flame.
Exposure Controls/Personal Protection Special instructions for protection and hygiene: Safety shower and eye bath should be located in immediate work area. Provide general and/or local exhaust ventilations to control airborne levels below the exposure guidelines.
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Respiratory protection: Use an approved air respirator. Hand protection: Use heavy rubber gloves. Eye protection: Use chemical safety goggles. Skin protection: Use protective clothing impervious to this material. \
Stability and Reactivity Conditions to avoid: heated condition Materials to avoid: oxidizing agents. Hazardous decomposition products: Toxic fumes of monoxide, carbon dioxide.
3.6. Process Instrumentation and Control and Safety aspect Process Instrument Control The main goal of all the major units is to minimize the extent of undesirable processes and reaction. Quality control and the proper installation of an efficient process instrumentation and control system in the plant are two very important tools for monitoring this requirement. By use of instruments having varying degrees of complexity, the values of variables like, temperature, pressure, density, viscosity, specific heat, conductivity, PH, humidity, dew point, liquid level, flow rate can be recorded continuously and controlled within narrow limits. Process instrumentation and control aid the economic function of any operation by maintaining, improving and controlling the various process parameters like flow rates,
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temperature, pressure, level, composition etc. An efficiently controlled process plant system also ensures greater safety in its operation. The parameter measurement could be direct or indirect. Instrumentation and control systems must justify the additional investment in them. Process control must aid the smooth operation of the plant and show adequate returns in terms of greater productivity, quality and stability of the various processes and in producing the desired results.
Functions to be performed by the instrumentation system ● Indicating ● Recording ● Controlling The process control instruments should be capable of functioning under and withstanding the process conditions of temperature, pressure, chemical environment and other adverse conditions on the plant. It is advisable to set norms, standards and practices to ensure that the instruments are interchangeable, easy to maintain and install. Proper code must be followed. Other features could be ruggedness, accuracy and quick response. With respect to our plant, controls for the following variables may be required: Pressure: Pressure measurement systems including inductive, capacitive, and piezo-electric gauge, absolute and differential pressure; calibration of gauges; selection criteria and specifications; ISA symbols and case study. Level: Level measurement systems including resistance, capacitance, radiation and optical methods; selection criteria and specification; ISA symbols and case study. Temperature: Temperature measurement systems including platinum resistance, thermistors, thermocouples; pyrometers; selection criteria and specifications; ISA symbols and case study. Density and Flow: Flow measurement systems including venturi tube, orifice plate, magnetic flow meter, vortex meter, ultrasonic flow meter, Pitot-static tube, coriolis meter, mass flow meters; density measurement systems including vibrating element and radiological devices; selection criteria and specifications; ISA symbols and case study. Followings are the described various sensors available for controlling these parameters.
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Temperature control(subsection of above para) Temperature is a very common process variable and temperature control is critical to maintaining product quality and ensuring safe and reliable operation of many processes. There are mainly two devices that are most widely used for temperature measurement: ● Resistance Temperature Indicators (RTD's) ● Thermocouple Thermocouples are fabricated from two electrical conductors made of two different metal alloys. At one end of the cable the two conductors are electrically shorted together by crimping, welding, etc. This end of the thermocouple, the hot or sensing junction, is thermally attached to the object to be measured. The other end, the cold or reference junction is connected to a measurement system. Thermocouples generate an open-circuit voltage, called the Seebeck voltage that is proportional to the temperature difference between the sensing (hot) and reference (cold) junctions. Resistive Temperature Devices, a resistance-temperature detector (RTD) is a temperature sensing device whose resistance increases with temperature. An RTD consists of a wire coil or deposited film of pure metal whose resistance at various temperatures has been documented. RTDs are used when applications require accuracy, long-term stability, linearity and repeatability. RTDs can work in a wide temperature range; some platinum sensors handle temperatures from 165°C to 650°C.
Level measuring element (second para of subsection) There are two methods used to measure the level of a liquid: ● Contact Level Measurement ● Non-Contact Level Measurement Contact Level Measurement Contact level measurement, as the name implies, requires that the sensing element be in contact with material being measured. Continuous level measurements can be performed with: Direct Methods: With direct level measurement the sensor is in contact with the material over
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the entire span that we wish to measure. Direct contact continuous level measurement is commonly used in bulk powder storage silos and un-agitated tanks. RF capacitance/resistance level sensors are the typical direct contact level sensors for both the point and continuous level variety. Indirect Methods: With indirect level measurement the sensor is in contact with the material at a single point and the tank level is inferred from this point measurement. Pressure transmitters measuring hydrostatic head are typically used for indirect contact continuous level measurement.
Flow Measurement (third para of subsection) Flow meter is a device that measures the rate of flow or quantity of a moving fluid in an open or closed conduit. Flow measuring devices are generally classified into five groups. ● Differential Pressure meters: Fixed restriction variable head type flow meters using different sensors like orifice plate, venturi tube, flow nozzle, Pitot tube and Dall tube. ● Mechanical type flow meters: Quantity meters like positive displacement meters etc. ● Inferential type flow meters: Variable area flow meters (Rotameters), turbine flow meter target flow meters etc. ● Electrical type flow meters: Electromagnetic flow meter, Ultrasonic flow meter, mass flow meters, Laser Doppler Anemometers etc. ● Other flow meters: Purge flow regulators, Flow meters for Solids flow measurement, Cross-correlation flow meter, Vortex shedding flow meters, flow switches etc.
Distributed System for Process Control Earlier, plants were constructed with a distributed system in the sense that the individual controllers were located near the process equipment with which interacted. To control and adjust the operating parameter, operator had to go to each area consuming unnecessary resources. So, controllers were then started to be maintained in a single room so that operator could quickly assess the status of the process and make adjustments. The remote multiplexer is being further used. This unit consists of minicomputer and microprocessor. The process
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signals are scanned, converted to digital and transmitted to central computer located adjacent to the control room. So a single path is shared for all of these processes as against an individual signal path for each process. Based on the above mentioned parameters, automatic control has generally been accepted throughout the chemical industry. The resultant savings in labour combined with improved ease and efficiency of operations has more than offset the added expense for instrumentation. We have also used high speed computers as they serve vital tool in the operation of the plant. The primary objectives of the designer when specifying instrumentation and control schemes are: Safe plant Operation: ● To keep the process variables with in known safe operating limits. ● To detect dangerous situations as they develop and to provide alarms and automatic shutdown systems. ● To provide interlocks and alarms to prevent dangerous operating procedures. ● Production rate: To achieve the design product output. ● Product quality: To maintain the product composition with the specified quality standards. ● Profit: To operate the lowest production cost, commensurate with the other objectives.
IV. Environmental Protection and Energy conservation
4.1. Environmental Aspect The
International
Standards
are
based
on
the
methodology
known
as
Plan-Do-Check-Act(PDCA). PDCA can be briefly described as follows: ● Plan: establish the objectives and processes necessary to deliver results in accordance with the organization’s environmental policy. ● Do: implement the processes.
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● Check: monitor and measure processes against environmental policy, objectives, targets, legal and other requirements, and report the result. ● Acts: take actions to continually to improve performance of the environmental management system. Many organizations manage their operations via the application of a system of processes and their interactions, which can be referred to as the “process approach”. ISO 9001 promotes the use of the process approach. Science PDCA can be applied to all processes, to methodologies are compatible. This International Standards contains only those requirements that can be objectively audited. Those organizations requiring more general guidance on a broad range of environmental management system issues are referred to ISO 14004. This International Standards does not establish absolute requirements for environmental management.
4.1.a Air Pollution Storage Tank Emissions. Product storage tank emissions are controlled with double seal floating roofs or, in some cases, water scrubbers. Field experience indicates that a removal efficiency of 99% can be achieved with water scrubbing. Product Transport Loading. Emissions of product transport loading vents are gathered and sent to a flare or incinerator for VOC control. Destruction efficiencies of 98-99% are achieved using the flare and greater than 99% using incineration. Absorber Vent Gas. The absorber vent gas stream contains nitrogen, oxygen, un-reacted propylene, hydrocarbon impurities from the propylene stream, CO, water vapor, and small quantities of acrolein. The treatment of air emissions normally takes place on-site and usually at the point
of
generation. Waste gas treatment units are specifically designed for a certain waste gas composition and may not provide treatment for all pollutants. The petrochemical industry has increasingly reduced the emissions from point sources, and this makes losses from fugitive sources relatively more important.
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Petrochemical processes usually operate with closed process equipment because of reactant/product characteristics (e.g., high volatility, high toxicity, high hazard risk), and reaction conditions (e.g., high temperatures and pressures) and this has associated environmental benefits. Special fields of attention with regard to air emission prevention are: ● Raw materials and fuel composition; ● Required volume of process air; ● Presence of, and need for, inert gases in the process (e.g., N2 from ambient air); ● Energy consumption and the combustion conditions.
The major concern in atmospheric emissions from petrochemical complexes is emissions of VOCs. Release of toxic/hazardous components and their impact on plant surroundings needs special attention. The petrochemical industry is characterized by toxic / hazardous chemicals that are handled and processed in large volumes and so external safety is an important issue.
VOCs Emissions Control Generally the control on hydrocarbon emissions has been attempted by employing equipment design standards, control technologies and inspection/maintenance requirements. Improved technology has a great potential in fugitive emission control. In recent years, manufacturers of seals, packing, and gaskets for process equipment have designed their products to control fugitive vapour leaks. These more effective seals, packing, etc., are expected to result in lower emissions and lower costs for monitoring and maintenance programs. Hydrocarbon emissions can pose not only environmental risk but also safety risks. Indian petrochemical industries have been following inspection routine to ensure that any leaks do not lead to incidents. In such inspections sensory perceptions of the operators and LEL detectors play a vital role. This same program when extended with the use of monitoring instruments and appropriate frequency will lead to control of environmental risks and has been commonly called as Leak detection & Repair (LDAR). The effectiveness and costs of VOC prevention and control depend on VOC species, VOC concentration, the flow rate, and the source. Resources are typically targeted at high flow, high
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concentration, process vents, but recognition should be given to the cumulative impact of low concentration diffuse generation sources. Following table identifies the properties needed to select the appropriate control technique for each identified stream generated by a process source.
Process vents Process vents usually represent the largest source of VOCs generation from petrochemical processes. Wherever possible, VOCs should be reused within the process. The potential for recovery depends on: ● Composition: In technical and economic terms, a gas stream containing one VOC (or a simple mixture) will be more amenable to re-use than one containing a complex mix. Likewise, high concentration streams (with low levels of inerts) are more amenable to reuse. ● Restrictions on reuse: The quality of recovered VOCs should be of a suitable quality for re-use within the process, and should not generate new environmental issues. ● VOC value: VOCs that are derived from expensive raw materials will be able to sustain higher recovery costs.
The next best alternative is to recover the calorific content of carbon by using VOCs as a fuel. If this is not possible, then there may be a requirement for abatement. The choice of abatement technique is dependent on factors that include VOC composition (concentration, type and variability) and targeted emission levels. For example: ●
Pre treatment to remove moisture and particulates, followed by
●
Concentration of a dilute gas stream, followed by
●
Primary removal to reduce high concentrations, followed by
●
Polishing to achieve the desired release levels.
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The most frequent approach to point source control is the application of add-on control device. These devices can be of two types: combustion and recovery. Applicable combustion devices are thermal incinerators, catalytic incinerators, flares and boilers/process heaters. Applicable recovery devices include condenser, absorbers, and adsorbers. The combustion devices are more commonly applied control devices, since they are capable of high removal efficiencies for almost any type of toxic gases. Selection of applicable control technique is made on the basis of stream specific characteristics and desired control efficiency.
The choice of the best technique will depend on site-specific circumstances.
Storage Tanks:Emissions from storage tanks may contribute significantly to the total hydrocarbon emissions. The controls to be specified for each type of fluid, needs to be worked out preferably based on assessment of quantum of emissions, nature of hydrocarbons emitted (i.e., their toxicity) and the percentage reduction achieved by the controls.
Oil-Water Separators:Assessing the safety of control technologies is of paramount importance. Since the covering of API separators can potentially lead to explosive environment in the Oil Water separators, suitable safety measures need to be incorporated.
Fugitives Emissions Control Fugitive emissions to the air environment are caused by vapour leaks from pipe systems and from closed equipment as a result of gradual loss of the intended tightness. Although the loss rates per individual piece of equipment are usually small, there are so many pieces of equipment in a typical petrochemical plant that the total loss of VOCs via fugitive routes may be very significant. LDAR programmes are therefore important to identify leak sources and to minimise losses. Fugitive emissions can be controlled by elaborate leak detection, repair and equipment modifications. Many plants have implemented LDAR programmes in which various sources of
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fugitive emission like leaks from valves, flanges, pump seals, etc., are routinely monitored for leaks and maintained on regular basis.
4.1.b Liquid Effluent 4.1.b.1 Possible Sources The major sources of water pollution in our industry are: 1. Drains 2. Spills or leak 3. Metals
1. Drain: Drain of hot water into rivers or other location where infiltration may occur are harmful to living organisms.
2. Spills/leakages: Spill or leakage of any component i.e. ethylbenzene, styrene, methylene, ethylene are harmful to the environment and living organisms and are soluble in water. So, water washing treatment should be done immediately after spillage. and if, leakage is there in large quantities then, absorbent paper is used for absorbing the spill and then, water washing is done.
3.Metal: Metals may occur in effluents, for example, through the use of catalyst i.e.,Fe2O3. Metals generally need to be removed by separate treatment, because they cannot be removed efficiently in biological treatment plants.
4.1.b.2 Wastewater Prevention Technique 1. General prevention techniques Before considering wastewater treatment techniques, it is first necessary to fully exploit all the opportunities for preventing, minimizing and reusing wastewater. However, water use, effluent generation and effluent treatment are all intrinsically linked and should be considered in combination. A typical exercise in preventing wastewater may include the following steps:
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Step 1: Identify wastewaters - The first step is to identify all wastewater sources from a process and to characterize their quality, quantity and variability. An analysis is useful to identify those sources that use most water and contribute most wastewater. Further clarification is provided by the preparation of plans that show all drain networks, points of arising, isolation valves, manholes and points of discharge.
Step 2: Minimize water flows - The overall aim is to minimize the use of water in the process in order to obviate effluent production or, if that is not possible, to produce more concentrated effluents. It will be necessary to identify the minimum quantity of water that is needed (or produced) by each step of the production process and then to ensure that these requirements are implemented by such practices as: ● Use of water-free techniques for vacuum generation (e.g., use the product as a sealing liquid in vacuum pumps, use dry pumps) ● Employ closed loop cooling water cycles. ● Use management tools such as water-use targets and more transparent costing of water. ● Install water meters within the process to identify areas of high use.
Step 3: Minimize contamination - Wastewaters are created by contamination of process water with raw material, product or wastes; either as part of process operation, or unintentionally. The following techniques can prevent this contamination:
Process operation: ● Use indirect cooling systems to condense or cool steam phases (not direct injection systems) ● Use purer raw materials and auxiliary reagents (i.e., without contaminants). ● Use non-toxic or cooling water additives with lower toxicity (e.g., chromium
based
additives).
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From spills: ● Fit secondary containment to vessels and pipe-work that pose a high risk of leaks. ● Provide spill clean-up material (adsorbents, drain plugs, etc) at strategic points around the installation and prepare spill contingency plans. ● Use separate collection systems for process effluent, sewage and rainwater (although there may be cases where the blending of effluent streams offers treatment advantages).
Step 4: Maximize wastewater reuse - Even when wastewaters are produced/generated they do not necessarily have to be sent to a treatment plant.
2. Process Modification
In-plant processes All in-plant treatment options require segregation of process waste streams under consideration. If there are multiple sources of a particular pollutant or pollutants, it/they require segregation from the main wastewater sewer. However, similar sources can be combined for treatment in one system.
In-plant practices are the sole determinant of the amount of wastewater to be treated. There are two types of in-plant practices that reduce flow to the treatment plant. First, there are reuse practices involving the use of water from one process in another process. Second, there are recycle systems that use water more than once for the same purpose. Reduction in water usage sometimes may be more cost-effective in reducing the quantity of wastewater discharged than water reuse or recycle. Good housekeeping is one inexpensive method of wastewater reduction. Many of the wastewater streams are suitable for reuse within the plant.
Water quality Standards by CPCB
Solution
Permissible Limit
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TDS
850 mg/l
Suspended solids
350 mg/l
Nitrogen as N
85mg/l
Phosphorus as P
20mg/l
BOD5
300 mg/l
Alkalinity
200 mg/l
4.1.c Solid Disposal Waste Disposal Techniques Spent catalysts are generally sent back to the suppliers. Solid waste may be disposed by the following methods:
1. Landfill: Landfilling is the main method of disposal of municipal solid in most countries. Unlike incineration, landfilling is not capital intensive and does not require skilled laborers. Landfills dispose of municipal solid wastes directly, as well as the residue that remain after recycling, composting, and incineration. Regardless of the level of technology used, landfilling is very simple process waste is dumped into a disposal area where, depending upon the type of landfill, the material may be compacted, and covered with a layer of soil. Over time, organic wastes such as paper and food decompose to produce methane, carbon dioxide, water, organic acids and other chemicals. The rate of decomposition depends upon many factors including moisture content, pH, and temperature, degree of compaction, wastage and composition. When degradation occurs, the volume of the original waste is reduced, providing additional landfill capacity. Strong odors are emitted as the organic wastes decompose. Inorganic wastes such as metals and glass do not decompose, and remain essentially unchanged over time.
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2. Incineration: In the incineration process, wastes are burned at very high temperatures and byproducts are released into the atmosphere and concerned into incineration ash. The byproducts which are released into the atmosphere contain dust, acidic gases, vaporized metals, toxic chemicals such as dioxin, all of which have been linked to public health and environmental degradation. These byproducts can be reduced with a variety of air pollution technologies such as scrubbers which remove particulates before they are released into the atmosphere. The incinerator ash is highly toxic as it contains a high concentration of heavy metals, which stay in the incinerator while other wastes are burned, from batteries and other waste products.
4.1.d Noise Pollution Noise Pollution at Petrochemical Industries The large petrochemical plants and refineries are highly regulated concerns because of the materials and processes involved and their potential impact on nearby communities and the environment. In some jurisdictions a plant’s noise levels must be assessed when seeking regulatory permits and approvals for new facility construction, plant expansions or for the addition of new processes or equipment. Petrochemical faculties bring some unique noise and acoustical engineering challenges. Unlike most other industrial facilities, petrochemical processes operate largely outdoors, with the processing equipment located on open-frame steel structures. These operations which include pumps, compressors, blowers, agitators and coolers, run out in the open, with limited barriers in place to restrict equipment noise from carrying beyond the confines of the plant.
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Compounding this is the sheer size and scale of these operations, which incorporate a large and varied amount of stationary sound sources, along with miles of complex, intertwined piping systems. As a result, the noise levels generated by these facilities can often be significant. Identifying key, major contributors to the excesses within the plant labyrinth as measured from nearby community locations can be challenging. In general it is produced, at every stage in industry by various aspects like welding, drilling, running machinery, motors, operation of cranes, grinding, turning, forging, steaming, boiling, cooling, heating, painting, pumping, packing, transporting etc. It creates very serious of largescale noise problems that significantly affect the working people as well as surrounding people.
As mechanical noise is the major part of industrial noise and is due to machinery of all kinds and often increases with the type of operation and power capacity of the machines. The characteristics of industrial noise vary considerably depending on specific industrial process. High noise levels common in petrochemical industries can be due to presence of unsteady force and it’s structural elements caused by moving parts, vibration of heavy equipments, sound from engines, gear, bearings, rotating and reciprocating machines, combustion, fans, pressurized flow, during shifting of raw materials and end products, trucks and dumpers etc.
For Petroleum industries the noise pollution may generate at any phases of development including: ● Seismic Operations ● Construction Activities ● Drilling & Production ● Aerial Surveys ● Transportation.
4.2. Energy Conservation
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With the rising population of the world and rapidly increasing per capita consumption in the developing countries, energy conservation has become the focus of attention all around the world, particularly in energy intensive petrochemical industry. The fast depleting petroleum resources, which are estimated to be just around 89*10^9 barrels as reserves (sufficient for just another 30 years) have led to the exploration of new energy resources. In this context, both conventional and nonconventional sources of energy are to be studied.
7.2.1 Alternate Energy Resources Renewable energy resources have become more important now a day in process plants. The major renewable energy forms and their present use and prospects have been tabulated below.
Solar Energy Electrical/ thermal conversion of solar energy in which electricity is generated using solar concentrating mirrors, absorbers and high temperature thermodynamic cycle can be used for both industrial and domestic use. In industry, much of the energy required is used for relatively low temperature applications such as space heating, dehydration of food, heating water for production and processing of low pressure steam.
Biomass Conversion Heat, fuel, electricity or chemical feed stocks undergo cultivation and chemical processing under the action of terrestrial and aquatic plants. Other sources from which energy can be derived include industrial. Agriculture, human and animal wastes. The final products of these processes may be methane, ethylene, hydrogen, alcohol, heat, steam, charcoal, other solid fuels and synthetic oils.
Wind Energy Wind is utilized to propel turbines and air foils, which convert it to electrical or mechanical energy. A 3.5 m diameter rotor develops about 0.16 BHP in a 15-mph wind can pump to 35 gallons of water per minute to a height of about 10 cm.
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Tidal Energy Ocean thermal energy conversion into electricity is another possible source of energy. This is due to fact that oceans are the largest solar collectors and storage system. We can also make use of thermal gradients that exists beneath the water surface and derive heat from these.
Nuclear Energy More than 1900 tons of uranium reserves are presents in the earth. Given proper measures, this form of energy is very competitive and an excellent substitute for fossil fuels. However, this form of energy is viewed with some reservations due to the inherent hazards of radioactive pollution.
7.2.2 Energy Conservation Measures The increasing cost of primary fuel has broadened the range of the heat recovery applications that can be economically justified. In a typical chemical concern with a profit margin of Rs. 4 per Rs. 100 sales, a saving of Rs. 1 in energy cost is approximately equivalent to an increase of Rs. 25 in sales. The entire gamut of energy conservation operations can be classified into two broad categories: 1. Energy Concept: The term energy has its origins in last of thermodynamics. It can be redefined in terms of enthalpy or entropy change or temperature difference. In each process, the sum of all the inputs are always greater than the sum of all the outputs, the differences being the energy losses. The endeavour of all energy conservation step is to minimize this energy loss. 2. Pinch Concept: Every chemical industry used hot and cold streams. The hot streams are cooled while the cold streams get heated up. These are called the hot and cold end “Approach”. ΔT, i.e. the temperature difference between the hot and cold end need not remain same through the temperature range. In a grand composite curve, all the hot and
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cold streams are combined to form the hot composite and cold composites respectively. There is a situation when ΔT becomes minimum. This point of closest approach is called pinch of the integrated heat exchanger (HEN) and signifies zero heat transfer in the grand composite curve.
To achieve energy conservation, the following three rules must be followed: ● No heat transfer across the pinch ● No cooling above the pinch ● No heating below the pinch Apart from the above, some more measures taken for the energy conservation are: Boiler & Steam systems Increase the efficiency of the condense system Replace improperly sized steam traps Upgrade the quality of insulation in the plant Reuse the hot water stream previously served
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V. Plant Utilities
The word "Utilities" is now generally used for the ancillary services needed in the operation of any production process. These services will normally be supplied from a central site facility; and will include: 1. Instrument Air 2. Electricity. 3. Steam, for process heating. 4. Cooling water. 5. Water for general use. 6. Demineralized water. 7. Compressed air. 8. Inert-gas supplies. 9. Refrigeration. 10. Effluent disposal facilities Secondary utilities: 1. Maintenance facilities 2. Roadways 3. Rail/road facilities 4. Fire protection
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5. Plant sewer system and waste disposal 6. Plant buildings 7. Plant security
5.1. Air for Process and Instrumentation For plant utilities we use secondary measuring instruments. These are the elements of a measuring information system that indicate or record the values of the quantities being measured. There are various modifications of secondary measuring instrument: single channel types (which indicate or record); multi-channel types (which simultaneously indicate and record the values) etc. The most important part of any secondary measuring instrument is the energy-generation and energy transmission systems which used to relay the signals. In the pneumatic system, the energy generating facility is composed of an air compressor, air dryer and storage tank. Pneumatic secondary instruments rely on the slight movement of flapper nozzle mechanism to sense signal change. Therefore clean dry air must be provided to ensure proper operation. The air is typically supplied throughout the plant in ½ inch (12 mm) pipes and at 40-60 psi. This pressure is reduced to a standard 20 psi for operation of each pneumatic instrument. Pneumatic signals are usually transmitted through tubing, usually ¼ inch (6mm) from feed to control room and within the control room between instruments. In the generation of compressed air there are two main equipment: 1. Air receivers: A small tank is provided after the compressors in the installation of compressor which is known as air receivers. An air receiver serves a fourfold purpose. ● As a surge tank to damping the pulsation of air delivered by the compressor. ● It is used as cooler. ● As a storage vessel of air. ● Removal of the oil and moisture contained in the air.
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2. Air compressors: Compressors have numerous forms, the exact configuration being based on the application. There are two basic modes: a) Intermittent: - This mode of compression is cyclic in nature, in that a specific quantity of gas is ingested by the compressor, acted upon, and discharged before the cycle is repeated. This type of compressor is also referred by positive displacement compressors, of which there are two distinct types; reciprocating and rotary. b) Continuous:- This mode is one in which the gas is moved into the compressor, is acted upon, moved through the compressor, and discharged without interruption of the flow at any point in the process. Continuous-mode compressors are also characterized by two fundamental types: dynamic and ejector. In our case both instrumentation and process air are required. All pneumatic controls in the plant require instrument air which is supplied in air compressor house. A slight malfunctioning of this unit may result in complete failure of all the units. The piping is over designed and extreme care is taken to prevent piping failure.
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5.2. Heat Transfer Media Heat transfer media are defined as fluids which absorb and provide thermal energy to the process equipment. Properties of heat carriers: (i) High rate of heat exchange (ii) Absence of corrosion effects (iii)Cheap and easily available (iv)Low viscosity (v) Non-toxic (vi) Non-inflammable and thermally stable The heat transfer media being used in our plant is: Steam Steam offers the following advantages over the other heat carriers: (i) It is thermally stable over the entire range of operation. Also it has less corrosive effects. (ii) Water is the cheapest and most commonly available heat carrier. Reasons for choosing steam ● Steam has many important advantages such as high latent heat, constant temperature requiring practically no control, easy production from commonly available water, high value of heat transfer coefficient during condensation, no special problems in handling and transportation. However, its use is generally restricted to about 220°C because of its low critical temperature. ● High pressure steam is a costly affair as it requires boilers and other processing and handling equipment to be at high pressure. ● Recently a concept of cogeneration in which high pressure superheated steam is used in turbines for power generation has picked up. ● The exhaust of turbine is used for thermal heating.
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● Now a days, the exhaust steam available at a low pressure of 1.5 – 2 atm being used as a supplement to process steam of high pressure.
5.3. Water Use of raw water: A plant water supply is separated into process, cooling, potable, fire water and utility water systems. Brief descriptions of the different water uses in industries are given below. Process water: water is typically used for various purposes where the water is closely contacted with the reactants. Softened water is usually used for these purposes. Cooling water: Water-cooled condensers, product coolers (heat exchangers) and other heat exchangers can use a large amount of water in a plant. Some industries use air coolers, where the process stream is exchanged with air prior the being sent to a cooling water heat exchanger. This will minimize the use of cooling water in the industry. Potable water: Potable water is required for use in kitchens, wash areas and bathrooms in plants as well as in safety showers/eyewash stations. City water or treated groundwater can be used for this purpose. In remote locations or in small towns a portion of the treated water from the plant softening unit may be diverted for potable water use. The treated water must be chlorinated to destroy bacteria, and then pumped in an independent system to prevent potential crosscontamination. Potable quality water may also be required in some specialist chemical operations (e.g. as a diluent). Fire water: The requirements for fire water in industries are intermittent, but can constitute a very large flow. Often, industries collect stormwater from non-process areas and store it in a reservoir dedicated to the fire water system in the plant. Provisions are typically made for a connection (for use in emergency situations) of the fire water system into the largest available
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reservoir of water. Usually this is the raw water supply since fire water requires no treatment. Seawater or brackish water is often used as fire water by plants located along coastal areas. Utility water: Utility water is used for miscellaneous washing operations, such as cleaning an operating area. It should be free from sediment but does not require any other treatment.
Raw water treatment: The raw water treatment in a industry creates wastewater and sludges that require disposal. The following section describes the best practices with respect to these discharges. Raw water treatment—best practices ● Lime softening: When lime softening is used for raw water treatment, the sludge generated in this process should be thickened, and optionally dewatered. The thickener overflow water can be discharged directly without any further treatment, when local regulations allow. The sludge that is generated should be disposed off-site. Not discharging it to the sewer in the refinery will prevent the introduction of inert solids into the sewer in the industry which in turn will avoid creation of more oil sludge that requires disposal. ● Ion exchange: The use of ion exchange for treatment of raw water creates an alkaline wastewater stream and an acidic wastewater stream as a result of the regeneration of the ion exchange beds. These streams should be collected in a tank and the pH neutralized prior to being discharged directly to an outfall (bypassing wastewater treatment) if allowed by local regulation. ● Reverse osmosis: The use of reverse osmosis for raw water treatment results in the creation of a reject stream that is very high in dissolved solids. This reject stream should be discharged directly to an outfall (bypassing wastewater treatment) if allowed by local regulation. Water Storage: Water Storage Facilities serve multiple purposes within a distribution system. The main purposes of finished water storage: • Equalizing supply and demand • Increasing operating convenience
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• Leveling out pump requirements • Decreasing power costs • Providing water during power source or pump failure • Providing large quantities of water to meet fire demands • Providing surge relief • Increasing detention times • Blending water sources There are many styles and construction materials for storage facilities. Selection of type and construction material is generally based on hydraulic considerations and cost. Storage facilities, depending on design can provide direct access to treated water as in open reservoirs or through hatches and vents as in closed reservoirs. Buried reservoirs are also susceptible to groundwater intrusion; however, this is not a viable means of intentional contamination. Depending on the size and design of the distribution system, finished water storage reservoirs can present a single point of failure or contamination or, to a lesser extent, disruption or contamination to particular portions of the service area. Historically, storage facility location has been driven by hydraulic needs, not security needs. Security needs have been of minor concern.
Cooling Tower Design Conditions: Cooling towers are heat removal devices used to transfer process waste heat to the atmosphere. Cooling towers may either use the evaporation of water to remove process heat and cool the working fluid to near the wet-bulb air temperature or in the case of "Close Circuit Dry Cooling Towers" rely solely on air to cool the working fluid to near the dry-bulb air temperature. Common applications include cooling the circulating water used in oil refineries, chemical
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plants, power stations and building cooling. The towers vary in size from small roof-top units to very large hyperboloid structures that can be up to 200 metres tall and 100 metres in diameter, or rectangular structures that can be over 40 metres tall and 80 metres long. Smaller towers are normally factory built, while larger ones are constructed on site. They are often associated with nuclear power plants in popular culture.
Cooling Towers: Operating Principle Cooled water is needed for air conditioners, manufacturing processes or power generation. A cooling tower is an equipment used to reduce the temperature of a water stream by extracting heat from water and emitting it to the atmosphere. Cooling towers make use of evaporation whereby some of the water is evaporated into a moving air stream and subsequently discharged into the atmosphere. As a result , the remainder of the water is cooled down significantly. Cooling towers are able to lower the water temperature more than devices that use only air to reject heat , like the radiator in a car , and are therefore more cost –effectiveness and energy efficient.
A cooling tower is determined by the properties with the following parameters. ➢ CT inlet temperature and CT outlet temperature ➢ Wet bulb temperature and Dry bulb temperature ➢ Water flow rate
Dry bulb temperature of air entering the cooling tower of any affect the amount of water evaporated. This temperature also affects the flow of hyperbolic towers and dry weather in any indirect-contact cooling tower element affects the working position. Use of air conditioning cooling tower thermal capability of a 1.25 per kW of heat dissipation base of evaporative cooling is expressed in terms of nominal capacity. Nominal cooling capacity of 25 to 6 ° C inlet air wet bulb temperature, 54 ml / s, water temperature 35 ° C is defined as 29 5 ° C to reduce the required cooling. 1.25 per kW / kW evaporator capacity of these circumstances, cooling tower
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heat throws. These values are based on traditional assumptions and inferences conditions typical air-conditioning evaporator taken every kilowatt of heat for 'cooling tower 0, 25 kW or remove the heat of an additional compressor. Values of the nominal capacity of the tower is not used for special applications and specific operating conditions are generally thermal performance capability of the air entering wet bulb temperatures entering and leaving water temperature, water flow rate is expressed in the basis.
5.4. Refrigeration Efficient industrial refrigeration systems are developed through proper design, the use of premium efficiency equipment, and the installation of appropriate system controls, as well as regular maintenance. Energy costs are a significant expense for these businesses. For example, approximately 25% of the electricity consumed by the food processing industry is used for process cooling and refrigeration. Nevertheless, despite the high energy costs associated with refrigeration and the potential savings from increased efficiency, the historical focus on designing and installing new refrigeration equipment hasbeen to develop systems that can meet a facility’s energy load at a minimum capital cost. Energy use and operating costs have had a lower priority.
Refrigeration systems are designed to achieve and maintain the specific required conditions of a facility’s refrigerated space by producing enough cooling to overcome the heat added by external and internal loads as well as the heat generated by the product. Refrigeration systems usually comprise four major components—compressor, condenser, expansion device, and evaporator— which are shown in Figure. Several equipment types and technologies are available for each of the major components; in many cases, each system component comes from each of the major components; in many cases, each system component comes from a different manufacturer. To maximize the overall efficiency of a refrigeration system, it is important to consider the interaction among components as well as the individual performance of each. Following is shown a diagram representing a basic refrigeration system:
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Figure: Basic Refrigeration Cycle Various types of refrigerants exist, but many of them are being phased out due to increased regulation. Refrigerants usually fall into one of the following groups:
CFCs – chlorofluorocarbons HCFCs – hydrochlorofluorocarbons HFCs – hydrofluorocarbons HCs – hydrocarbons NH3 – ammonia
CFCs have been widely used in the past but are now phased out of production due to their high ozone-depleting potential (ODP). HCFCs also have ODP; they are strictly regulated and are in the process of being phased out. HFCs and HCs have zero ODP and are being used as replacements for refrigerants with ODP. Ammonia is toxic but has no ODP and is used extensively in industrial refrigeration systems. Several advantages of ammonia have contributed to its popularity in industry, including high latent heat and therefore less required mass flow, low pressure losses in connecting piping, and low reactivity with refrigeration lubricants.
Following is provided an overview of common energy efficiency measures, specifically: Optimized compressor sequencing Moderately oversized condensers Floating head pressure control
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Increased suction pressure Variable frequency driver Premium efficiency motors Demand-based defrosting Insulation High-efficiency lighting fixtures and controls Rapid-closing doors
5.4. Electricity and Power
Equipment
Power
Week
Total
Consumptio
y
Weekly
Annual
Number of
Total
n instrument
Usage
consumpti
Consumpt
Equipments
Annual
(W)
(h)
on(kWh)
ion(kWh)
or people
Power(kW)
Computer Box
72
43.2
3.456
179.712
112.5
22464
Laptops
18
43.2
0.864
44.928
90
4492.8
Document Shedder
450
4.5
2.25
117
9
1170
Projector
135
4.5
0.675
35.1
9
351
36
151.2
6.048
314.496
9
3144.96
17.19
893.88
10.8
10726.56
Computer Network/Hub printer/copier/fax machine coffee maker mobile phone charger
374.4
9
3.744
194.688
18
3893.76
3.6
9
0.036
1.872
90
187.2
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Telephones/ intercom
151.2
65.7
3375
100.8
378
Ventilation System
36
151.2
6.048
Fans
36
100.8
HVAC
Lifts
3416.4
180
683280
0.9
19656
315
6.3
2205
4.032
209.664
450
104832
391.5
24429.6
5.4
146577.6
Lighting(max. i.e 35% of
the
total
energy
consumption)
49.5
45
2.475
128.7
900
128700
Vacuum Cleaners
1350
13.5
20.25
1053
5.4
6318
Microwave
1260
9
12.6
655.2
1.8
1310.4
fridge/freezer
187.2
151.2
31.4496
1635.379
1.8
3270.758
water Heater
81
54
4.86
252.72
10.8
3032.64
Hand drier
421.2
32.4
15163.2
Dish Washer
299.7
1.8
599.4
1084.5
72
86760
CCTV System
54
151.2
9.072
Plant Equipments and others
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VI. Organizational Structure and Manpower Requirement
Grade
Gross salary (per month in Rs)
A0
2,00,000
A1
1,50,000
A2
1,00,000
A3
70,000
A4
50,000
A5
18,000
A6
8,500
B0
50,000
B1
20,000
B2
6,000
Designation
Minimum Education qualification
Number
Grade
President
BTech+MBA with at least 20 years experience
1
A0
Vice President
BTech+MBA with at least 15 years experience
2
A1
General Manager Medical Officers
BTech+MBA with at least 12 years experience
2
A3
Legal Head
LLB
1
A3
Security Head
Retired army officer
1
A3
Administration
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Fire and Safety Head
Graduate (B.A)
1
A3
Fire Man
Diploma
5
A6
Medical Staff
Diploma
4
A6
General Manager
BTech+MBA with at least 12 years experience
1
A2
Staff
Graduate
4
A5
General Manager
CA with 10 years of Experience
1
A2
Accountants
M.com
4
A4
General Manager
BTech+MBA with at least 12 years experience
1
A2
Managers
BTech(chemical)
4
A4
Shift Engineers
BTech(chemical)
12
B0
Operators
BTech(chemical)
16
B1
Labor
BTech(chemical)
30
B2
General Manager
BTech(chemical) with 5 years experience
1
A2
Engineers
BTech
10
B0
Staff
Graduate
12
B1
BTech(chemical) with 5 years experience
1
A3
Personal (HR)
Finance
Production
Technical
Maintenance Senior Manager
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Engineer
BTech(chemical) with 3 years experience
2
A4
Operator
Diploma
6
B1
Labor
High School
10
B2
Total salaries of employees = 47,862,000 Rs per annum = 683,742 $/annum
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VII. Market Prospects
7.1 A brief analysis of demand and supply of the product of the past 5 years and next five years. Global Dimethyl Carbonate Production The key drivers of dimethyl carbonate production are its largest applications in the industries of polycarbonates, paints and coatings. Polycarbonates are currently in very high demand from the rapidly growing end-user industries of automotive and electronics. Both industries are currently in full swing and are expected to continue growing in the near future. As a result, the higher demand for polycarbonates becomes a driver for the manufacture of dimethyl carbonate. Similarly, the paints and coatings industry is being boosted by the construction industry, consequently upping the demand for dimethyl carbonate. With all these factors of influence in place, the global market for dimethyl carbonate is expected to progress at a CAGR (Compound Annual Growth Rate) of 6.6% between 2015 and 2023 in terms of revenue. By the end of 2016, this market revenue should be reaching US$440 mn. By the end of 2023, the market is expected to be valued at US$690.1 mn. In terms of volume, dimethyl carbonate global production is expected to weigh in at 599 kilo tons.
Asia Pacific Demand for Dimethyl Carbonate on the Rise: By the end of 2023, the Asia Pacific demand for dimethyl carbonate is expected to be at 49.26% of the market. Europe comes in at second place in terms of demand, followed by North America in third.
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China is a massive contributor to the Asia Pacific demand for dimethyl carbonate. Together with Japan, the two regions are expected to take up more than three quarters of the total dimethyl carbonate volume in Asia Pacific by 2023. In fact, China is considered to be a top producer and consumer of dimethyl carbonate in the world currently, as the players in this country also export large quantities of dimethyl carbonate to emerging economies. Europe recognized dimethyl carbonate as a non-toxic chemical in 1992, after which it steadily started to replace chloromethane, phosgene, and methyl chloroformate in several end-use industries. A majority of the demand for dimethyl carbonate in Europe is expected to continue originating from Germany and France. Dimethyl Carbonate Market, By Application Global dimethyl carbonate market size for polycarbonate was valued at over USD 200 million in 2015. Polycarbonate is a transparent and strong engineering thermoplastic used in automotive, glazing, electronics, optical media, medical, lighting and appliances markets. Robust growth in the end user industries such as automotive and electronics, along with increasing product usage in these sectors will positively influence industry growth over the forecast timeframe.
Global dimethyl carbonate market share for solvent is projected to expand at over 6% CAGR over the forecast timeframe. The product is an inexpensive oxygenated solvent along with having excellent solubility properties. It can dissolve numerous coating resins. It can also be employed in auto refinish and concrete coatings with its promising solubility, odor, evaporation rate and economic profiles. Furthermore, it can also be used in floor coatings, steel drum linings, traffic paints and architectural coatings owing to boost industry growth.
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U.S Dimethyl Carbonate Market size, by application, 2013-2024 (USD million)
Source: www.gminsights.com
Polycarbonate Industry demand for Dimethyl Carbonate Continues to grow. By 2023, 53.2% of the total volume of dimethyl carbonate produced is expected to be taken up by the polycarbonate industry. Dimethyl carbonate is an important constituent in the manufacture of polycarbonates, as it is used to produce diphenyl carbonate, one of the core chemicals in the condensation polymerization process that produces polycarbonates. The applications of polycarbonates are diverse and include appliances, lighting devices, medical devices, optical media, electronics, and automobiles. Most of these industries, especially the automotive and electronics industries, are showing a positive growth rate. Therefore, their demand for polycarbonates is expected to drive the production of dimethyl carbonate.
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7.2 Present production capacity/licensed capacity in the country giving the status of the production Analysis of Import of dimethyl carbonate By India:
Ref: www.zauba.com
Ref: www.zauba.com
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\
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7.3 Export Potential
Analysis of Export of dimethyl carbonate By India :
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7.4 Marketing set-up and area of consumption
The thriving expansion of some of the key end-use industries of dimethyl carbonate is one of the key factors leading to the steady rise in demand and consumption of this organic compound. Manufacturers are also increasingly preferring dimethyl carbonate as a solvent over other toxic reagents such as phosgene. The usage of dimethyl carbonate in the production of antibiotics, such as ciprofloxacin and carbadox, and pesticides has also witnessed steady expansion in the recent years and these applications continue to remain lucrative for the market.
It is estimated that the global dimethyl carbonate market will massively benefit from the vast surge in uptake of electronics and passenger vehicles, especially across Asia Pacific. The increasing usage of the compound in these products will prove to be highly lucrative for the global dimethyl carbonate market in the longer run. Additionally, the market will likely benefit from the increasing demand from the paints and coatings industry. The thriving construction industry in regions such as the Middle East and Africa and Asia Pacific is expected to drive the regional paints and coatings markets, which will, in turn, propel the growth of this market.
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VIII. Site selection: The flexibility of the plant & site selection is mainly based upon the following: i. Raw materials availability ii. Markets iii. Energy iv. Climate v. Transportation facilities vi. Water supply vii. Waste disposal viii. Labor supply ix. Taxation and legal restrictions x. Site characteristics xi. Flood and fire protections
Based upon all these factors we have chosen Kandla (SEZ), Gujarat as the potential site for the project. Availability of port makes the procurement of raw material by imports quite easy.
Alternatives sites may be Mundra, Ahmedabad and Surat (Gujarat), but due to the availability of SEZ (400 Ha) for chemicals in Kandla and being a PCPIR (Petroleum, Chemicals and Petrochemicals Investment Region), it is the best suited for our project.
Advantages of Gujarat The advantages in selecting Gujarat as the site for the project are described below: 1. Raw material supply: As mentioned above, these all suppliers are suited in Gujarat, near our project site. The availability of raw material makes the selection of Kandla as the project site very obvious. Handling and transportation of the raw materials will be eased due to the lesser distance between the supplier and project site.
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2. Robust Infrastructure: a) Dependable Power supply: This factor is a key to industrial development. Present power generation capacity of Gujarat is 9,628 MW, plans afoot to raise it to 25,000 MW by 2012. Per capita power consumption is 1354 units against national average of 665 units. Also there is rich availability of natural gas (34 MMCD) and lignite (1,072 MMT) in Gujarat. b) Transportation facilities: Total road length in Gujarat is 74,018 Km, whereas rail length is 5,188 Km (8.25 % of India), 13 airports and 42 ports along 1,600 km coastline also make Gujarat a favorite location for industries and businesses. Kandla (itself a large seaport city), situated between Vadodara and Surat, is well connected through roadways, railways and airways. c) Utilities: Kandla has always been prosperous because of its location on the Narmada River. Although water tends to be scarce in Gujarat, one never finds difficulty in getting water in Kandla. Because of this, agriculture and other linked commercial activities have flourished in Kandla.
3. Initiatives by Government: a) Licensing policy: • In Chemical sector, 100% FDI is permissible. • The entrepreneurs need to submit only IEM with the Department of Industrial Policy and Promotion provided no locational angle is applicable. b) Custom duty: • The peak rate of custom duty on most Chemicals is 7.5%. • On basic raw materials like acid grade fluorspar, Sulphur, rock phosphate, natural borates are 5%. • On most building blocks and feedstock, the duty is 5% (ethylene, propylene, crude, naphtha, benzene, xylene, Ethyl benzene) c) Excise duty: • On almost all chemicals the excise duty is 16%.
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4. SEZ Advantages: For SEZ units● Income tax incentives: 10-year corporate tax holiday on export profit, 100% for the initial 5 years and 50% for the next 5 years. ● Other benefits; ○ Exemption of electricity duty—10 years ○ Duty free procurement of capital goods (including second hand capital goods), raw materials and consumable spares from domestic markets. ○ Full freedom for sub-contracting. ○ Facility to realize and repatriate export proceeds within 12 months. ○ Facility to retain 100% foreign exchange receipts in the export earner’s foreign currency account. ● Indirect tax incentives (for both SEZ units & Developers) ○ Nil custom duty. ○ Nil excise duty. ○ Exemption from central sales tax. ○ Exemption from service tax. ○ Exemption from securities transaction tax. ○ Exemption from tax on sale of electricity for self-generated and purchased power. Besides above, Gujarat has very liberal labor policies for SEZ and SEZ Development committee monitors infrastructure development for each SEZ.
5. Global competitiveness: ● The chemical industry in Gujarat is a significant component of the State’s economy, contributing to more than 51% of Indian production of major chemicals with revenues at approximately more than INR US$ 3 billion. Gujarat contributes 15% of the total national chemical exports.
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● Petrochemical Industry in Gujarat produces 13.048 Million Tons of petrochemical products and contributes around 62% to the total production of the country. ● Bulk of the exports from this sector goes to market such as USA, Europe and other developed countries- a clear sign of global competitiveness. ● Gujarat has been the ideal destination for several leading MNCs including BASF, Bayer, DuPont, GE Plastics, Claim Energy, Solvay, Shell, British Gas, Perstrop, Huber, Heubach colours and Cheminova.
6. Market Advantages: While the State Chemicals industry exhibits several similarities to the global chemical industry, there are several characteristics specific to the Gujarat across sub-segments. At the industry level, Gujarat chemical industry is characterized by: ● High domestic demand potential, as the Indian markets develop and per capita consumption level increase. ● High degree of fragmentation and small-scale operations. ● Limited emphasis on exports due to domestic market focus and smaller scale of operation. ● Low cost competitiveness as compared to other countries.
7. Quality Workforce and Educational Infrastructure: Gujarat is also famous for its educational infrastructure and quality workforce. ● Least man days lost due to industrial unrest. ● Large pool of skilled technical personnel available. ● 39 engineering colleges offering diploma courses in chemical engg. ● 49 Polytechnics offering diploma courses in chemical engg. (e.g. K. J. Polytechnic, Kandla ● Location of kandla in Gujarat.
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8.2 Project Layout Plant Layout considerations After selecting a plant site for the plant, plant layout is a crucial factor in the economics and the safety of process plant. Some of the ways, in which plant layout contributes to safety and loss prevention (SLP), & which are included in the layout design are: 1. Economic considerations: construction and operation cost, 2. Segregation of different risks. 3. Minimization of vulnerable pipe work. 4. Containment of accidents. 5. Limitation of exposure. 6. Efficient and safe construction. 7. Efficient and safe operation. 8. Efficient and safe maintenance. 9. Safe control room design. 10. Emergency control facilities. 11. Firefighting facilities. 12. Access for emergency services. 13. Security. 14. Future Expansion. 15. Modular construction.
Our plant layout mainly includes the following buildings and construction as per the process requirements and support activities: 1. Plant Area (including boiler house, pump house, cooling tower, water treatment plant etc.). 2. Power plant. 3. Storage. 4. Repair and Maintenance Workshop. 5. Plant Utilities.
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6. Loading Area (train, tankers, trucks etc.). 7. Stores. 8. R & D Centre. 9. Laboratories. 10. Quality Control Wing. 11. Pollution Control Wing. 12. Fire & Safety Station. 13. Medical Centre. 14. Bank & Post Office. 15. Recreation & Staff Facilities. 16. Administrative Block. 17. Marketing Block. 18. Training Centre. 19. Petrol Pump. 20. Security Wing. 21. Canteen. 22. Parking (Light Vehicles & Heavy Vehicles) 23. Lawns & Fountains. 24. Green Belt Area. 25. Space for Future Expansion. A site layout for the plant is provided on the next page. Considerations have been given for the future expansions. Some area has been marked for Green Belt. Hazardous materials are kept at a safe distance from the offices and other staff facilities.
Description: Location of buildings ● Buildings which are the work base for several people should be located to limit their exposure to hazards. Analytical laboratories should be in a safe area, but otherwise as close as possible to the plants served. So, should workshops and general stores. The main
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office block should always be near the main entrance and other administration buildings should be near this entrance if possible. ● Other buildings such as medical centers, canteens etc. should be in a safe area and the latter should have ready access for food supplies. ● All buildings should be upwind of plants which may give rise to objectionable features. Water drift from cooling towers can restrict visibility and cause corrosion or ice formation on plants or transport routes and towers should be sited to minimize this. ● Another problem is recycling of air from the discharge of one tower to the suction of another, which is countered by placing towers cross-wise to the prevailing wind. The entrainment of effluents from stacks and of corrosive vapors from plants into the cooling towers should be avoided as should the siting of buildings near the tower intakes. ● The positioning of natural draught cooling towers should also consider resonance caused by wind between the towers. The problem of air recirculation should also be borne in mind in siting air-cooled heat exchangers. Economic Considerations ● The cost of construction can be minimized by adopting a layout that gives the shortest run of connecting pipe between equipment and the least amount of structural steel work. However, this will not necessarily be best arrangement for operation and maintenance. ● Some features which have a particularly strong influence on costs are foundations, structures, piping and electrical cabling. This creates the incentive to locate items on the ground to group items so that they can share a foundation or a structure and to keep pipe and cable runs to a minimum. Safety Considerations ● Plants which may leak flammables should generally be built in the open or, if necessary, in a structure with a roof but no walls. If a closed building cannot be avoided, it should have explosion relief panels in the walls or roof with relief venting to a safe area. Open air construction ventilates plants and disperses flammables but as already indicated, scenarios of leakage and dispersion should be investigated for the plant concerned.
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● Fire spread in buildings should be limited by design, as should fire spread on open structures. Sprinklers and other protective systems should be provided as appropriate. Plants which may leak toxics should also generally be built in the open air. The hazardous concentrations for toxics are much lower than those for flammables, however, and it cannot be assumed that an open structure is always sufficiently ventilated. ● Ventilation is necessary for buildings housing plants processing flammables or toxics. Air inlets should be sited so that they do not draw in contaminated air. The relative position of air inlets and outlets should be such that short circuiting does not occur. Exhaust air may need to be treated before discharge by scrubbing or filtering. ● Blast walls may be needed to isolate potentially hazardous equipment and confine the effect of the explosion. At least two escape routes for operators must be provided from each level in the process building. Operations ● Access and operability are important to plant operation. The routine activities performed by the operator should be studied with a view to providing the shortest and most direct routes from the control room to items requiring most frequent attention. ● Equipment that needs to have frequent operator attention should be located convenient to the control room. Valves, sample points and instruments should be located at convenient positions and heights. Sufficient working space and headroom must be provided to allow easy access to equipment. ● Good lighting on the plant is important, particularly on access routes, near hazards and instrument reading. Operations involving manipulation of equipment while observing an indicator should be considered so that the layout permits this. Maintenance ● Maintenance costs are very large in the chemical industry. In some cases, the cost of maintenance exceeds the company’s profit. The engineer must design to reduce these costs. ● Heat exchangers must be sited such that tube bundle can be easily withdrawn for cleaning and tube replacement.
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● Heat exchangers must be sited such that tube bundle can be easily withdrawn for cleaning and tube replacement. ● Vessels that require frequent replacement of catalyst or packing should be located on the outside of the building. ● Equipment that requires dismantling for maintenance such as compressors and large pumps, should be place under cover. Modular Construction ● For convenience of efficient management, the whole plant is assembled section wise at the plant manufacturer’s site in the form of modules. These modules will include the equipment, structural steel, piping and instrumentation. Modules are then transported to the plant site, by road or sea. ● We know that technology is improving day by day. That’s why keeping future expansion in mind, equipment should be located so that it can be conveniently tied in with any future expansion of the process.
Plant Layout
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IX. Economic Evaluation and Profitability of Project
Total Direct Costs:
S.NO
Item
Percent of Purchased Cost
1
Purchased Equipment Cost
100
2,142,200
149,954,000
2
Purchased Equipment Installation
39
835,458
58,482,060
3
Instrumentation and Control
13
278,486
19,494,020
4
Piping
31
664,082
46,485,740
5
Electrical equipment and materials
10
214,220
14,995,400
6
Buildings( Including services)
29
621,238
43,486,660
7
Yard improvements
10
214,220
14,995,400
8
Service Facilities
55
1,178,210
82,474,700
9
Land
6
128,532
8,997,240
5,050,344
353,524,080
Cost in $
Cost in INR
Total direct plant cost (D)
Cost in $
Cost in INR
Indirect Plant Cost: S.N O
Item
Percent of Purchased Cost
1
Engineering and supervision
32
685,504
47,985,280
2
construction Expenses
34
728,348
50,984,360
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3
Contractor's fee
18
385,596
4
Contingency
36
771,192
53,983,440
5
Legal Expenses
4
85,688
5,998,160
2,270,732
158,951,240
Total Indirect Plant cost (I)
26,991,720
Total Capital Investment: S.NO
Description
Cost in $
Cost in INR
1
Total Indirect Cost(I)
2,270,732
158,951,240
2
Fixed Capital investment (FCI), D+I
7,321,076
512,475,324
3
Working Capital (WC), 15% OF FCI
1,098,161
76,871,270
Total capital Investment
10,689,969
748,297,830
Total Product Cost:
Another equally important part is the estimation of costs for operating the plant and selling the products. These costs can be grouped under the general heading of Total Product Cost A tabular form is very useful for estimating total product cost and constitutes a valuable checklist to preclude omissions.
Basis for calculating total product cost is: 1. The Total Product Cost is calculated based on the Annual Cost Basis. 2. Number of days working per year is taken as 320 days. 3. Plant is running in 3-shifts i.e. 24 hrs per day. 4. Capacity of the plant per year is 12000 ton of DMC production.
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Step 3.a. Cost of Raw Materials-
S.No.
Raw Material
Quantity Per Year (ton)
Rate ( per ton), in $
Cost (per year) in $
1
Methanol
16,382.361
800
13,105,888
2
Urea
1,267.200
300
380,100
3
Zinc Oxide
2418
1000
2,418,000
Total raw material cost
10,799,080
Step 3.b. Cost of Power and Utilities S.No
Utility
Consumption
Rate, in $
Cost(per year $)
1
Steam(in ton)
579906
17.14 per ton
9,939,589
2
Power(in kwh)
97270272
50.07 $/ kWh
7,642,660
3
Water(in m3)
18272211.9
0.42 per m3
7,674,329
Total
25,256,578
Step 3.c .Total Annual Direct Production Cost S.n o.
Description
% of DPC
Cost in $
1
Utilities
8.5
477,120
2
Operating labour
0.25
14,032
3
Operating supervision
0.15
8,419
4
Maintenance and repairs
3.3
185,235
5
Operating supplies
3.7
207,687
6
Laboratory charges
0.1
5,613
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Total Annual direct Production Cost
898,106
Step 3.d. Fixed Charges S.NO
Nature of Expenditure
Cost in $
1
Depreciation(11% PEC)
148,049
2
Taxes(5% TDP)
280,659
3
Insurance(1% PEC)
13,459
Total Annual Fixed Charges
442,167
Also, Plant Overhead cost is taken to be 30% of the cost of operating labour, supervision and maintenance. Thus, Plant Overhead Cost = 58,096 INR
Step 3.e.Total Manufacturing Cost (M) S.N o
Description
Total Annual Cost in $
1
Direct Production Cost
5,613,186
2
Fixed Charges
442,167
3
Plant Overhead Cost
58,096
Total Manufacturing Cost(M)
6,055,353
Step 3.f. General Expense S.N o
Nature of Expenses
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Cost in $
166
1
Administrative Cost
171,428
2
Distribution & Marketing Cost
420,000
3
Research & Development
520,000
Total GE(G)
1,111,428
Total manufacturing cost (M) = 6,055,353 Total General Expense = 1,111,428 $ Total Product cost=M+G =7,166,781 $
Step 5. Profitability Analysis
Gross profit = Annual revenue through sale - Annual operating cost - salaries of employees = 52,257,142.86 -43,612,226 = 8,644,916 $ Total direct investment = 10,689,969 $ Rate of return = 13.41% Payback period =
Total Fixed Investment Net profit + Depreciation = 1.74 years
Market Value of Finished Product Annual Revenue Through Sales (MC + DMC) Gross Profit Assuming tax percent
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$ per ton
52,257,142.86
$
8,644,916
$
20
%
167
Net Profit
6,915,932
$
Payback Period
1.74
Years
Rate of Return
13.41
%
Step 6. Break Even Analysis For breakeven production annual sales equals the annual cost of production Assuming 100% product demand is there, Annual Direct Production Cost Annual Sales
5,050,344
$
14,400,000
$
Selling Price per Kg
1200
$ per ton
Direct Production Cost (per Kg)
394
$ per ton
Tons production for Break even Point
4208
ton/year
Thus, We find that from 3rd year onwards, cash flow becomes positive which implies that the cost invested is recovered. We had calculated Payback period to be 1.74 years, hence the above results confirm it.
References: ❏ Pichayapan Kongpanna, Varong Pavarajar, Rafiqul Gani , Suttichai Assabumrungrat, “Techno-economic evaluation of different CO2-based processes for dimethyl carbonate production” Chemical Engineering Research and Design 93 (2015) 496–510 ❏ Kartikeya Shukla and Vimal Chandra Srivastava, “Synthesis of organic carbonates from alcoholysis of urea: A review” ISSN: 0161-4940 (Print) 1520-5703 (Online) Journal homepage: http://www.tandfonline.com/loi/lctr20
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❏ Paula Saavalainen, Satish Kabra, Esa Turpeinen, Kati Oravisjärvi, Ganapati D. Yadav, Riitta L. Keiski and Eva Pongrácz, “Sustainability Assessment of Chemical Processes: Evaluation of Three Synthesis Routes of DMC” Hindawi Publishing Corporation, Journal of Chemistry, Volume 2015, Article ID 402315, 12 pages http://dx.doi.org/10.1155/2015/402315 ❏
Dengfeng Wang, Xuelan Zhang, Wei Wei, Yuhan Sun, “Synthesis of Dimethyl Carbonate from Methyl Carbamate and Methanol Using a Fixed-Bed Reactor”, Chemical Engineering Technology.
❏ Coulson & Richardson’s Chemical Engineering Volume 6, Chemical Engineering Design 4th Edition, R. K. SINNOTT ❏ Introduction to Chemical Equipment Design, Mechanical Aspects, B.C Bhattacharya
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A PROJECT REPORT submitted in partial fulfilment of the requirement for the award of the degree of
BACHELOR OF TECHNOLOGY In
CHEMICAL ENGINEERING By:
RAHUL SHRIVASTAV (14111032) (GROUP 1, Production Factor 1)
DEPARTMENT OF CHEMICAL ENGINEERING INDIAN INSTITUTE OF TECHNOLOGY ROORKEE
CERTIFICATE This is to certify that the project titled – Dimethyl Carbonate Production using Methanol and Urea which is hereby presented by Group 1 in partial fulfillment of the requirements of the awarding of the degree of Bachelor of Technology at Indian Institute of Technology Roorkee, is a genuine account of his work carried out during the period from October 2017 to April 2018 under our supervision and guidance.
Date: April 16, 2018
Prof. Shishir Sinha Head of Department Department of Chemical Engineering IIT Roorkee
Dr. Vimal Chandra Srivastava Associate Professor Department of Chemical Engineering IIT Roorkee
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ACKNOWLEDGEMENT
It is with a deep sense of gratitude and indebtedness that we express our sincere gratefulness to our project guide Dr. V.C. Srivastava, Associate Professor, Department of Chemical Engineering, Indian Institute of Technology Roorkee, under whose able guidance, constant supervision and encouragement, this work has been accomplished. We thank him for taking time out of his busy schedule and aiding us with his priceless suggestions, encouragement and cooperation, which in turn helped us, enhance the scientific merit of the present project work. Without his guidance and mentorship, this work would have never reached its completion. The constant motivation and support from him made us understand the depths of various techniques and processes being used in current scenario. We’d also like to thank our Institution and entire staff of Central Library, IIT Roorkee and Departmental Library, IIT Roorkee who provided us with facilities for various books, research papers and internet.
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Index
I. General II. Summary Executive summary of the project… ............................................................................................ 6 III. Project Details 1. Introduction .............................................................................................................................. 8 2. Project Description...................................................................................................................9 a. Uses and present status of the product/importance of the problem ................................. 9 b. (i) Available processes for the production of the product with brief description… ......... 10 (ii) Techno-economic appraisal of alternative processes/schemes… ............................... 13 (iii) Status of technologies/schemes available .................................................................. 13 (iv) Selection of technology/scheme… ............................................................................ 14 (v) Source of knowhow of selected process/technology… ............................................... 16 c. Raw Materials ...................................................................................................................... 16 (i) Detailed specifications… ............................................................................................. 17 (ii) Requirement of raw materials… ................................................................................. 18 (iii) Availability: indigenous/imported… ......................................................................... 18 (iv) Government policies for import of the raw materials… ............................................ 21 (v) Prevailing prices… ..................................................................................................... 22 (vi) Testing procedures for the raw materials… .............................................................. 22
3. Material and Energy Flow Information .................................................................................... 23 a. Material balance b. Energy balance
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4. Detailed Design of Equipment ................................................................................................. 38 a. b. c. d. e.
Process design of all major equipment ............................................................................. 38 Mechanical design of three major equipment .................................................................. 79 Drawings of 2 equipment as per BIS specification of equipment Design of Auxiliary Equipment ....................................................................................... 97 Major engineering problems of the plant with their possible remedies… ....................... 98
5. Materials Storage & Handling Facilities..................................................................................99 6. Process Instrumentation & Control and Safety Aspects ......................................................... 113 IV. Environmental Protection & Energy Conservation ........................................................ 117 1. Environmental Aspects ........................................................................................................... 117 a. b. c. d.
Air Pollution…...............................................................................................................118 Liquid Effluents… ......................................................................................................... 122 Solids Disposal................................................................................................................125 Noise Pollution…............................................................................................................126
2. Energy Conservation .............................................................................................................. 129 a. Possible usage of renewable resources… ....................................................................... 129 b. Energy conservation options… ....................................................................................... 131 V. Plant ……………………………………………………………………………….131
Utilities
1. Air for Process and Instrumentation ....................................................................................... 131 2. Heat Transfer Media ............................................................................................................... 135 3. Water ....................................................................................................................................... 138 a. Process and general water requirement and standards… ................................................ 138 b. Water treatment and storage facilities c. Cooling tower/spray ponds 4. Refrigeration… ....................................................................................................................... 139 5. Electricity/Power…..................................................................................................................141 VI. Organizational Structure and Manpower Requirement ................................................ 142 1. Organizational structure with chart 2. Manpower requirement
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VII. Market Prospects .............................................................................................................. 146 1. A brief analysis of demand and supply… ....................................................................... 146 2. Present production capacity… ........................................................................................ 148 3. Export potential (if any). ................................................................................................. 151 4. Marketing set-up and area of consumption… ................................................................. 152 VIII Site Selection & Project Lay-out ..................................................................................... 153 1. Critical points taken into consideration . 2. A plot lay-out of works
IX. Economic Evaluation & Profitability of the Project ....................................................... 162 1. 2. 3. 4. 5. 6.
Total project cost Detailed statement indicating the cost of production Cash flow chart Break Even point with detailed calculation Full justification of the selling price taken in the preparation of cash flow Implementation schedule
X. References ............................................................................................................................. 167 1. References should be given as per the guidelines of American Chemical Society Journals.
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II Executive Summary
This project is an attempt towards making a techno-economic evaluation of installing a 12,000 MTPA plant. For the production of dimethyl carbonate (DMC) using methanol and urea. The main advantage of this technology lies in the usage (for the production of urea) of carbon dioxide indirectly. This process can be used to convert a greenhouse gas, carbon dioxide, to a green chemical, dimethyl carbonate.
Cost Information Total Fixed Capital Investment (Rs)
748,297,830
Total Working Capital (Rs)
76,871,270
Production Cost (Rs)
3,052,855,820
Gross Profit (Rs)
605,144,120
Payback period: 1.74 years Selling Price at 100 % Production:
Employment Potential The organization consists of 6 divisions, namely Administration, Personal (HR), Finance, Production, Technical and Maintenance.
Division
Number of Employees
Administration
14
Personal (HR)
5
Finance
5
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Production
63
Technical
33
Maintenance
19
The plant has a total employment potential of 135 people.
Utilities
S.No
Utility
Consumption
Rate, in $
Cost(per year $)
1
Steam(in ton)
579906
17.14 per ton
9,939,589
2
Power(in kwh)
97270272
50.07 $/ kWh
7,642,660
3
Water(in m3)
18272211.9
0.42 per m3
7,674,329
Total
25,256,578
Profitability of the Project A minimum return rate of 13.41 % is assured. For a break even, annual sales is 4208 tonnes per year.
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III. Project Details
3.1. Introduction 3.1.1 Problem Statement and description The project demands a Technical and Economic feasibility report checking for a proposed project which will produce dimethyl carbonate from methanol and urea. Emphasis is to be laid on the fact that owing to the multiple uses of dimethyl carbonate and limited competition in the market, it offers huge export potential in the near future. As part of this project the following are to be detailed out : 1. Project details and technology 2. Material and Energy flow information 3. Detailed design of equipments ( Process and Mechanical) 4. Material storage and handling facilities 5. Environment protection and energy conservation 6. Plant utilities 7. Organisational structure and manpower requirement 8. Market prospects 9. Site selection and project layout 10. Economic evaluation and profitability of the project
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3.1.2 Introduction to the format of the report The complete report has been extended to a Span of seven chapters, each chapter focusing on dimension of the project.
● The first chapter covers summary of the project. ● The second chapter covers project details and problem statement analysis. ● The third chapter is the heart of the project. It is subdivided into three sections, each dealing with a distinct topic. The chapter cover problem statement and description, a brief literature review on various available process for production and basis of the final process selection. Requirement, availability, specification and testing procedures for the raw materials are also mentioned here. The next section in this chapter includes exhaustive process designing of all the major equipments in the plant. Mechanical designs of the some of the equipments have also been presented. Besides, the major engineering problems of the plant and their possible remedies are also discussed ● The fourth chapter deals with environmental protection and energy conservation in the plant. Possible sources of the pollutants of the all kinds are investigated and their mitigation measure is suggested. ● Chapter five discusses in full detail the utilities involved in the plant. Considerations are taken or various type of utilities their application range and their general facilities. ● Chapter Six discusses the market prospects of the DiMethyl carbonate. ● Site selection and project layout is covered in the seventh chapter. Alternative feasibility sites and weighed and best site selected. A plant layout of the works showing mandatory requirement is also attached. ● Chapter eight deals with assessment of the economic viability of the project. It shows in detail the project cost estimation cash flow diagram, break even point analysis and implementation schedule. ●
The ninth chapter encompasses the organization structure and manpower requirement of the project.
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3.2. Project Description 3.2.a Uses and present status of the product Dimethyl carbonate (DMC) (CH3OCOOCH3) has been considered as an environmentally benign chemical and applied widely during the last few years because of its low toxicity and quick biodegradation properties. Following are some of the uses of this ‘Green Chemical’. ● DMC is an important carbonylation and methylating reagent used in various fields such as medicine, pesticides, composite materials, flavouring agent and electronic chemicals. ● It is considered as an additive for gasoline due to the enhancement of the octane number. ● It can be used as a polar solvent in the chemical industry. ● Paints and Coatings : Dimethyl Carbonate can be used as VOC exempt solvent in many paints and coatings. DMC is a fast evaporating polar solvent. It can replace esters, glycol ethers and ketones in formulations. ● Fuel Additive : Because of its high oxygen content, DMC can be used as a fuel additive. ● Li-ion Battery : Lithium ion battery electrolytes use organic carbonates such as diethyl carbonate and complexes of lithium ions. Although processes for the production of DMC are well-established, for example phosgenation of methanol, oxidative carbonylation of methanol, and trans esterification of ethylene carbonate with methanol; the synthesis of DMC utilizing CO2 is an option worth investigating since all these techniques suffer from corresponding drawbacks such as toxicity, explosion hazards, reaction routine complex, and low conversion, respectively. Therefore, it is desirable to focus on new processes to avoid these shortcomings.
3.2.b.(i) Available processes for the production of DMC Methods for the production of DMC can be classified into two: Conventional and Nonconventional methods.
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Conventional Routes: ● Phosgene Route, ● BAYER Route (Partial carbonylation of methanol) Non-conventional Routes: These are CO2 based routes of production. ● Urea Route ● Synthesis from CO2 and Methanol ● Propylene Carbonate Route ● Ethylene Carbonate Route
Phosgene Route This process employs the traditional (pre-1980) method to produce DMC. Here phosgene reacts with methanol to form methyl chloroformate (CH3OCOCl), which further reacts with methanol to form DMC. COCl2 + 2 CH3OH ⇌ (CH3O)2CO+ 2 HCl
Partial carbonylation of methanol This non-phosgene process produces DMC by reacting methanol, carbon monoxide and oxygen in liquid phase, in the presence of a catalyst. The process has been licensed by BAYER for commercial production of DMC. CO + ½ O2 + 2 CH3OH ⇌ (CH3O)2CO + H2O
Urea Route
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In this process, methanol is added to urea for the alcoholysis reaction to produce DMC. It has been reported that the process involves a two-step reaction with methyl carbamate as the reaction intermediate. NH2CONH2 + CH3OH ⇌ NH2COOCH3 + NH3 NH2COOCH3 + CH3OH ⇌ CH3OCOOCH3 + NH3
Synthesis from CO2 and Methanol For the direct use of CO2 to produce DMC, it has been reported that CO2 could react with methanol at critical temperature and critical pressure of CO2 . Under mild conditions, a basic catalyst (ZrO2–MgO), a promoter (methyl iodide) and butylene oxide as a chemical trap to shift the chemical equilibrium are needed (Eta et al., 2011). CO2 + 2 CH3OH ⇌ (CH3O)2CO + H2O Propylene Carbonate Route DMC can be obtained through the transesterification of propylene carbonate and methanol. Various types of catalysts can be used such as basic quaternary ammonium ion exchange resins with hydroxide counterions. C3H6O + CO2 ⇌ CH3(C2H3O2)CO CH3(C2H3O2)CO + 2 CH3OH ⇌ (CH3O)2CO + C3H8O2
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Ethylene Carbonate Route Transesterification of ethylene carbonate with methanol produces DMC and ethylene glycol. Various types of catalysts can be used, such as poly-4-vinyl pyridine as a novel base catalyst and DABCO-derived (1,4-diazobicyclo[2.2.2]octane) basic ionic liquids. C2H4O + CO2 ⇌ (CH2O)2CO (CH2O)2CO + 2 CH3OH ⇌ (CH3O)2CO + (CH2OH)2
3.2.b.(ii) Techno-Economic appraisal of alternate processes : DMC can be used as a precursor for carbonic acid derivatives and as a methylating agent. Because of its high oxygen content, DMC has been proposed as a replacement for methyl tertbutyl ether (MTBE) as a fuel additive. The process of oxidative carbonylation of methanol on unsupported cuprous chloride suffers from catalyst deactivation, equipment corrosion, and difficulties in product separation, a number of alternative approaches have been investigated. These include cycloaddition of CO2 to epoxides with the use of titanosilicate molecular sieves, various transesterification methods, methanol carboxylation over zirconia, and electrochemical oxidative carbonylation of methanol . From a thermodynamic standpoint, the oxidative carbonylation of methanol remains the most favorable reaction. To overcome problems with catalyst separation inherent in liquid-phase processes, recent interest has focused on vapor-phase oxidative carbonylation of methanol over supported copper-based catalysts. CuCl and CuCl2 supported on activated carbon have been evaluated by a number of groups because of the inherent similarity of such catalysts to those used in the liquid-phase system . CuCl, CuCl2, and bimetallic PdCl2-CuCl2 deposited on mesoporous silica supports (HMS silica, MCM-41, and SBA-15) have also been evaluated.
3.2.b.(iii) Status of technologies/schemes available Although Phosgene route is a conventional route to produce DMC, phosgene is an extremely hazardous material and is classified by the US Department of Transportation (DOT) as a class-A
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poison. Therefore due to the inherent hazards and potential environmental problems in handling and waste disposal, it is crucial that this method is replaced by a more sustainable method. With regard to the BAYER Process, the process suffers from low production rate, difficulties in downstream separation because of the existence of binary azeotropes in the system methanolwater-DMC, and the need for corrosion resistant reactors. Urea route has many inherent advantages such as the consumption of CO2 as a raw material and the ability to recycle the waste NH3 stream for the production of Urea, thus making the process even more sustainable. DMC synthesis from the direct reaction of urea and methanol using bases, organic tin, metal oxides, and ionic liquids has been reported. However, the corresponding DMC yields were usually below 40% in the batch reactor.
3.2.b.(iv) Selection of Technology/Scheme: Compared to the traditional routes, Urea route is one such method that has many advantages such as ● Usage of CO2 as a raw material: This method is a potential strategy to counter the large scale emission of CO2 by using it as a chemical feedstock for conversion to more valuable chemical. ● Easy availability of raw material and safe operations: Having easily available raw materials such as urea and methanol is an advantage. Also this method does not involve any hazardous chemicals (like phosgene), thus it is inherently safer. ● Ammonia released during the reaction could be recycled for urea synthesis. Moreover urea synthesis can be integrated with the DMC production plant to enhance the sustainability of the overall process. In view of the above advantages, Urea route of DMC production was chosen for this project.
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Technical Details of the Urea Route of Production This manufacturing route comprises of two reactions:NH2CONH2 + CH3OH → NH2COOCH3 + NH3 NH2COOCH3 + CH3OH → CH3OCOOCH3 + NH3 The intermediate methyl carbamate (MC) (NH2COOCH3) is produced first and further converted to DMC by the consecutive reaction with methanol. Different catalytic studies performed for DMC synthesis from urea and methanol were studied from the literature. Zn-based catalysts have been widely recommended for the synthesis of DMC from urea or MC. DMC is produced by the reaction of urea with methanol via intermediate methyl carbamate (MC). In addition, ammonia released during reaction could be recycled for urea synthesis. No poisonous or corrosive gases were involved in this approach, and naturally abundant carbon dioxide was used as one of the starting materials. Those features made the direct carbonate synthesis more attractive from the environmental perspective. Catalysts in the direct synthesis method reported in the literature were bases,16,17 organotin catalysts,18-21 and metal oxides.16,17,22-24 The corresponding DMC yields were usually low (below 40%) in the batch reactors. Ryu et al.19 have patented a novel process, in which DMC was withdrawn during reaction via a reflux column above an autoclave reactor in the presence of organotin catalysts. A high DMC selectivity was obtained, but the organotin and cocatalyst were very complex, expensive, and difficult to handle. Sun25 and his co-workers reported a new process using polyphosphoric acid as the catalyst as well as an ammonia captor. The DMC yield in the batch operation was improved. Ammonium polyphosphate was however precipitated in the reactor during reaction, which caused problems in operation and separation. In our previous work, ZnO exhibited high activity toward the DMC synthesis.17 It was simple and nontoxic in comparison with the tin compounds. In this work, a new strategy was proposed for the DMC synthesis from urea and methanol based on the analysis of thermodynamic equilibrium and side reactions. The
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objective was to increase the DMC yield using catalytic distillation technique over a Zn-based catalyst. 3.2.b.(v) Source or know how of selected process/technology ● Pichayapan
Kongpannaa,
Varong
Pavarajarnb,
Rafiqul
Ganic,
Suttichai
Assabumrungrata: Techno-economic evaluation of different CO2-based processes for dimethyl carbonate production ● Dengfeng Wang,Xuelan Zhang, Wei Wei, Yuhan Sun2: Synthesis of Dimethyl Carbonate from Methyl Carbamate and Methanol Using a Fixed-Bed Reactor ● Kartikeya Shukla and Vimal Chandra Srivastava: Synthesis of organic carbonates from alcoholysis of urea: A Review
3.2.c Raw Materials (i) Detailed specifications Urea: Urea Specifications CAS No.
57-13-6
State
Prilled
Molecular weight:
60.60 g/mol
Water solubility:
Soluble
Density
1.335g/cm3
Urea Coating:
No anti-caking agent
MF
CH4N2O
Melting point
132.7°C
Nitrogen
46.60%
Moisture
0.36%
Biuret
0.80%
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Alkalinity (NH3)
0.02%
Aldehyde
0.8 mg/kg
Insoluble matter
11 mg/kg
Iron (Fe)
0.46 mg/kg
Source:https://www.alibaba.com/product-deta Methanol: Methanol Specifications CAS No.
67-56-1
Appearance
colorless, transparent
Molecular weight:
32.04 g/mol
Melting point
-97.8°C
Boiling Point
64.7°C
Relative Density
0.7914
Refractive Index
1.3287
Flash Point
16°C
Table No 3.2.1 Test Items
Standard
Results
Titratable Acid. mmol/g
Max 0.0005
0.0003
Titratable Base. mmol/g
Max 0.0002
0.00008
Solubility in H2O
Pass test
Pass test
UV Absorbance,(1.00-cm cell vs.water) at 205 nm
Max 1.00
0.708
at 210 nm
Max 0.60
0.411
at 220 nm
Max 0.30
0.197
at 230 nm
Max 0.15
0.086
at 240 nm
Max 0.05
0.033
DEPARTMENT OF CHEMICAL ENGINEERING INDIAN INSTITUTE OF TECHNOLOGY ROORKEE
17
at 260 nm
Max 0.01
0.006
Source:https://www.alibaba.com/product-detail/industrial-methanol 3.2.c.(ii) Requirement of raw materials and basic assumptions made in computing the raw material requirement for producing 12,000 TPA DMC Amount of Urea required: 12,000 TPA Amount of Methanol required: 16,380 TPA Computation and basic assumptions:After reviewing the literature, a conversion of 40% was taken for calculation of raw material. Using 12,000 TPA DMC, moles produced were calculated, which were back substituted to find the theoretical moles of raw materials required. The actual moles required was calculated by back substitution, using the yield data. Finally a 5% provision was included for the unavoidable losses and the molar data was converted back to MMTPA.
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3.2.c.(iii) Availability: indigenous/imported Urea: Import of Urea in last few Years
Production of Urea in last few Years
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Methanol: Methanol Stats for Imports, exports and net Imports
Methanol stats Indian capacity, consumptions and domestic production
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3.2.c.(iv) Government Policies on Import of raw materials Urea: Policies on import of urea have seen many changes with the change in government every five years Subsidy Provided by the government of india Internal Product: 13,700₹ per Metric Ton Imports: 37,898₹ per Metric Ton
Sr .no
Acts/Sections
Subject
1
Fertilizer Control Order, 1985
This has been issued under the Essential Commodities Act, 1955 and is administered by Department of Fertilizers in the Ministry of Chemicals and Fertilizers, Govt. of India. The FCO lays down as to what substances qualify for use as fertilizers in the soil, product-wise specifications, methods for sampling and analysis of fertilizers, procedure for obtaining license/registration as manufacturer/importer/dealer in fertilizers and conditions to be fulfilled for trading thereof, etc.
2
ITC (HS)- Schedule I and 2
Under ITC (HS) Code 31021000, it provides that import and export of Urea is restricted. ● Urea other than Industrial grade/Technical Grade can be imported by STE only. Industrial grade/Technical grade urea can be imported without license subject to actual user condition. ● Export of Urea is restricted and requires export licence from office of the DGFT.
3
DGFT notification No. 4 /2015-2020,dated 28.04.2015 [Issued under Para 1.02 and 2.01 of FTP read with Section 3 of the FT (D&R) Act, 1992 (Administrative Ministry: Ministry of Commerce & Industry, Department of Commerce).
It amends the ITC (HS) to provide that w.e.f. 28.04.2015, Import of Industrial Urea /Technical Grade Urea (TGU) is free, Subject to Actual User condition. Urea of grade other than Industrial/Technical grade can only be imported through State Trading Enterprises only.
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Methanol: There are no quantitative or other restriction on the import of methanol other than few obligations as per international convention. On Import of Methanol government of india imposes three tier tax scheme Basic Duty: 10% Countervailing Duty: 12% Special Countervailing Duty: 4%
(v) Prevailing Price Urea Price: 150$ per ton Methanol Price: 250$ per ton
(vi) Testing procedures for the raw materials Urea: In industries two major techniques are used to measure percentage purity of urea: ● Near-Infrared Spectroscopy Near-infrared spectroscopy (NIRS) is a spectroscopic method that uses the near-infrared region of the electromagnetic spectrum (from about 700 nm to 2500 nm). Typical applications include medical and physiological diagnostics and research including blood sugar, pulse oximetry, functional neuroimaging, sports medicine, elite sports training, ergonomics, rehabilitation, neonatal research, brain computer interface, urology (bladder contraction), and neurology (neurovascular coupling). There are also applications in other areas as well such as pharmaceutical, food and agrochemical quality control, atmospheric chemistry, combustion research and astronomy. ● Kjeldahl Method The Kjeldahl method or Kjeldahl digestion in analytical chemistry is a method for the quantitative determination of nitrogen contained in organic substances plus the nitrogen in inorganic ammonia and ammonium (NH3/NH4+). Other forms of inorganic nitrogen, for instance nitrate, are not included in this measurement. This method was developed by Johan in 1883.
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3. Material and Energy Flow Information
Material Balance Calculations Material Balance calculations were carried out using simulations in Aspen Plus software, except the reactor block, which was solved by hand calculations using the yield data reported in the research paper mentioned in the reference. HYSSRK method was used for calculations of all the unit operations. The material balance result obtained from simulation for all the individual unit operations is shown below.
Reactor
Process Specifications Reactor
REAC-IN
REAC-OUT
Temperature °C
53.32998
170
Pressure bar
1
1
Vapor Frac
1
1
Liquid Frac
0
0
NH3
6.096876
95.13
METHANOL
1320.574
1265.84
0
0
Material Balances Component Molar Flow kmol/hr
WATER
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DMC
0.0662855
19.59
0.00E+00
32.49
69
0
Total Flow kmol/hr
1395.737
1413.05
Total Flow kg/hr
46567.69
46383.94
-169620000
-183750000
-65761000
-72125000
MC UREA
Enthalpy Balances
Enthalpy J/kmol Enthalpy Watt
Cooler
Process Specifications Cooler
REAC-OUT
COLD-STR
Temperature °C
170
80
Pressure bar
1
1
Vapor Frac
1
0.9812263
Liquid Frac
0
0.0187737
95.13
95.13
1265.84
1265.84
0
0
19.59
19.59
Material Balances Component Molar Flow kmol/hr NH3 METHANOL WATER DMC
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MC
32.49
32.49
0
0
1413.05
1413.05
46383.94
46383.94
-183750000
-189300000
-72125000
-74305000
UREA Total Flow kmol/hr Total Flow kg/hr
Enthalpy Balances
Enthalpy J/kmol Enthalpy Watt
Distillation Column 1
Process Specifications
Distillation C-1
COLD-STR
DC1-BTM
DC1-TOP
Temperature °C
80
107.3366
32.75723
Pressure bar
1
1
1
Vapor Frac
0.9812263
0
0
Liquid Frac
0.0187737
1
1
Material Balances Mole Flow kmol/hr
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NH3
95.13
7.08E-10
95.13
1265.84
8.975058
1256.865
0
0
0
DMC
19.59
0.9264426
18.66356
MC
32.49
32.49
6.91E-08
0
0
0
1413.05
42.3915
1370.659
46383.94
2809.968
43573.98
-189300000
-89996000
-234270000
-74305000
-1059700
-89196000
METHANOL WATER
UREA Total Flow kmol/hr Total Flow kg/hr
Enthalpy Balances
Enthalpy J/kmol Enthalpy Watt
Pump
Process Specifications Pump
DC1-TOP
LIQ-1
Temperature °C
32.75723
33.47633
Pressure bar
1
30
Vapor Frac
0
0
Liquid Frac
1
1
Material Balances
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Component Molar Flow kmol/hr NH3
95.13
95.13
1256.865
1256.865
0
0
DMC
18.66356
18.66356
MC
6.91E-08
6.91E-08
0
0
Total Flow kmol/hr
1370.659
1.37E+03
Total Flow kg/hr
43573.98
43573.98
-234270000
-234080000
-89196000
-89124000
METHANOL WATER
UREA
Enthalpy Balances
Enthalpy J/kmol Enthalpy Watt
Distillation Column 2
Process Specifications
Distillation C-2
LIQ-1
DC2-BTM
DC2-TOP
Temperature °C
33.47633
190.4547
170.302
Pressure bar
30
30
30
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Vapor Frac
0
0
0
Liquid Frac
1
1
1
95.13
0.00486213
86.06514
1256.865
223.7292
913.4251
0
0
0
DMC
18.66356
16.84841
0.043145
MC
6.91E-08
6.25E-08
1.22E-27
0
0
0
Total Flow kmol/hr
1.37E+03
240.5825
999.5334
Total Flow kg/hr
43573.98
8686.536
30737.74
-234080000
-244220000
-208110000
-89124000
-16321000
-57780000
Material Balances Mole Flow kmol/hr NH3 METHANOL WATER
UREA
Enthalpy Balances
Enthalpy J/kmol Enthalpy Watt
Valve
Process Specifications Valve
DC2-BTM
DC3-IN
Temperature °C
190.4547
170.4644
Pressure bar
30
20
0
0.134518
Vapor Frac
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Liquid Frac
1
0.865482
0.00486213
0.00537384
223.7292
247.2865
0
0
DMC
16.84841
18.61589
MC
6.25E-08
6.91E-08
0
0
Total Flow kmol/hr
240.5825
265.9077
Total Flow kg/hr
8686.536
9600.582
-244220000
-244220000
-16321000
-18039000
Material Balances Component Molar Flow kmol/hr NH3 METHANOL WATER
UREA
Enthalpy Balances
Enthalpy J/kmol Enthalpy Watt
Distillation Column 3
Process Specifications
Distillation C-3
DC3-IN
DC3-BTM
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DC3-TOP
29
Temperature °C
170.4644
210.7092
168.2422
Pressure bar
20
20
20
Vapor Frac
0.134518
0
0
Liquid Frac
0.865482
1
1
0.00537384
2.46E-16
0.00537384
247.2865
2.472865
244.8136
0
0
0
DMC
18.61589
18.59727
0.0186158
MC
6.91E-08
6.91E-08
0.00E+00
0
0
0
Total Flow kmol/hr
265.9077
21.07014
244.8376
Total Flow kg/hr
9600.582
1754.457
7846.126
-244220000
-531560000
-223200000
-18039000
-3111100
-15180000
Material Balances Mole Flow kmol/hr NH3 METHANOL WATER
UREA
Enthalpy Balances
Enthalpy J/kmol Enthalpy Watt
Valve 2
Process Specifications
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Valve 2
DC3-TOP
S6
Temperature °C
168.2422
66.76251
Pressure bar
20
1
Vapor Frac
0
0.3714046
Liquid Frac
1
0.6285954
0.00537384
0.00537384
244.8136
244.8136
0
0
0.0186158
0.0186158
0.00E+00
0.00E+00
0
0
Total Flow kmol/hr
244.8376
244.8376
Total Flow kg/hr
7846.126
7846.126
-223200000
-223200000
-15180000
-15180000
Material Balances Component Molar Flow kmol/hr NH3 METHANOL WATER DMC MC UREA
Enthalpy Balances
Enthalpy J/kmol Enthalpy Watt
Cooler 2
Process Specifications
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Cooler 2
S6
S7
Temperature °C
66.76251
15
Pressure bar
1
1
Vapor Frac
0.3714046
0
Liquid Frac
0.6285954
1
0.00537384
0.00537384
244.8136
244.8136
0
0
0.0186158
0.0186158
0.00E+00
0.00E+00
0
0
Total Flow kmol/hr
244.8376
244.8376
Total Flow kg/hr
7846.126
7846.126
-223200000
-243600000
-15180000
-16568000
Material Balances Component Molar Flow kmol/hr NH3 METHANOL WATER DMC MC UREA
Enthalpy Balances
Enthalpy J/kmol Enthalpy Watt
Distillation Column 4
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Process Specifications
Distillation C-4
DC3-BTM
DC4-BTM
DC4-TOP
Temperature °C
210.7092
218.6633
174.626
Pressure bar
20
20
20
Vapor Frac
0
0
0
Liquid Frac
1
1
1
NH3
2.46E-16
0
0
METHANOL
2.472865
0.2834277
2.189437
0
0
0
DMC
18.59727
18.04759
0.5496806
MC
6.91E-08
6.91E-08
3.36E-20
0
0
0
Total Flow kmol/hr
21.07014
18.33102
2.739118
Total Flow kg/hr
1754.457
1634.788
119.6689
-531560000
-566290000
-293810000
-3111100
-2883500
-223550
Material Balances Mole Flow kmol/hr
WATER
UREA
Enthalpy Balances
Enthalpy J/kmol Enthalpy Watt
Flash
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33
Process Specifications Flash
DC2-TOP
S9
S10
Temperature °C
170.302
61.74774
61.74774
Pressure bar
30
1
1
Vapor Frac
0
1
0
Liquid Frac
1
0
1
NH3
86.06514
89.93245
5.192178
METHANOL
913.4251
381.7845
627.794
0
0
0
DMC
0.043145
0.0142802
0.0333893
MC
1.22E-27
0
0
0
0
0
Total Flow kmol/hr
999.5334
471.7312
633.0195
Total Flow kg/hr
30737.74
13766.09
20207.31
-208110000
-169930000
-236550000
-57780000
-22267000
-41596000
Material Balances Component Molar Flow kmol/hr
WATER
UREA
Enthalpy Balances
Enthalpy J/kmol Enthalpy Watt
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Distillation Column 5
Process Specifications
Distillation C-5
S9
DC5-BTM
DC5-TOP
Temperature °C
61.74774
65.29137
8.025282
Pressure bar
1
1
1
Vapor Frac
1
0
1
Liquid Frac
0
1
0
NH3
89.93245
0.8993245
89.03312
METHANOL
381.7845
377.9666
3.817845
0
0
0
0.0142802
0.0142802
0
MC
0
0
0
UREA
0
0
0
Total Flow kmol/hr
471.7312
378.8802
92.85097
Total Flow kg/hr
13766.09
12127.47
1638.616
Material Balances Mole Flow kmol/hr
WATER DMC
Enthalpy Balances
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Enthalpy J/kmol Enthalpy Watt
-169930000
-237120000
-52944000
-22267000
-24956000
-1365500
Mixer
Process Specifications Mixer
DC5-BTM
S7
S10
FEED
REAC-IN
Temperature °C
65.29137
15
61.74774
25
533.2998
Pressure bar
1
1
1
1
1
Vapor Frac
0
0
0
0.5035971
1
Liquid Frac
1
1
1
0.4964029
0
0.8993245
0.00537384
5.192178
0
6.096876
377.9666
244.8136
627.794
70
1320.574
0
0
0
0
0
0.0142802
0.0186158
0.0333893
0
0.0662855
MC
0
0.00E+00
0
0
0.00E+00
UREA
0
0
0
69
69
378.8802
244.8376
633.0195
139
1395.737
Material Balances Component Molar Flow kmol/hr NH3 METHANOL WATER DMC
Total Flow kmol/hr
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Total Flow kg/hr
12127.47
7846.126
20207.31
6386.79
46567.69
-237120000
-243600000
-236550000
449571000
-169620000
-24956000
-16568000
-41596000
17358400
-65761000
Enthalpy Balances
Enthalpy J/kmol Enthalpy Watt
Distillation Column 6
Process Specifications Distillation C-6
DC1-BTM
S3
MC
Temperature C
107.3366
67.51201
188.175
Pressure bar
1
1
1
Vapor Frac
0
0
0
Liquid Frac
1
1
1
NH3
6.06E-10
6.06E-10
1.65E-15
METHANOL
7.691363
7.651949
0.0394145
0
0
0
0.7940368
0.7027648
0.091272
27.85
0.00242851
27.84757
0
0
0
36.3354
8.357142
27.97826
Material Balances Mole Flow kmol/hr
WATER DMC MC UREA Total Flow kmol/hr
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Total Flow kg/hr
2408.596
308.6715
2099.925
-89986000
-267510000
-26914000
-908240
-621010
-209170
Enthalpy Balances
Enthalpy J/kmol Enthalpy Watt
3.4. Material Storage and Handling Facilities a. Distillation Column 1 Design Column Diameter Column Specifications:Feed (F): 33.6mol/s Reflux Ratio (R): 1.5 Distillate Rate (D): 19.6 mol/s Bottoms Rate (B): 13.9 mol/s No. of real stages: 36
Flow rate Calculations:Rectifying section:V = D(1+R) = 19.6*(1+1.5) = 49 mol/s L = D x R = 19.6*1.5 = 29.4 mol/s Stripping Section:L′m = L + liq part of F = 29.4 + 33.6 = 63 mol/s V ′m = V - vapor part in F = 49 - 0 = 49 mol/s DEPARTMENT OF CHEMICAL ENGINEERING INDIAN INSTITUTE OF TECHNOLOGY ROORKEE
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Calculation of Column Diameter: ρV F bottom = L′m = 19.05 x V ′m
LV
F LV
top =
L V
√
√
7.26
ρL
ρV ρL
=
19.05 x
√
400.05
1.25
√
= 0.109
720
= 0.002
1.01 755.09
Taking plate spacing as 0.45 m
Base K1 = 0.08 Top K 1 = 0 .078
Base uf = K 1 Top uf = K 1
√ √
ρL − ρV ρV ρL − ρV ρV
√ = 0.078 x √ = 0.08 x
720 − 1.25 = 1.25
1.92 m/s
755.09 − 1.01 1.01
= 2.13 m/s
Where uf = flooding velocity Actual velocity = 0.8 x flooding velocity Base actual vel = 1.536 m/s Top actual vel = 1.704 m/s
Net Area (base) =
Net Area (top) =
2 Max V apor volumetric f low rate = 2.98 m actual vel
2 Max V apor volumetric f low rate = 1.088 m actual vel
Taking downcomer area as 12% of the total, Total Area (base) A = Net Area c
0.88
2
= 0.121 m
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Column Diameter (base) Dc = 2.076 m 2
Total Area (top) A = Net Area c
0.88
= 10.734 m
Column Diameter (top) Dc = 1.254 m As bottom diameter > top diameter Dc = 2.076 m
Provisional plate design Column diameter Dc =2.076 m Column area Ac = 3.383 m2 Downcomer area Ad = 0.12 x Ac = 0.406 m2 Net Area An = Ac − Ad
= 2.977 m2
Active area Aa = Ac - 2Ad = 2.571 m2
Taking Hole area Ah as 10 per cent of Aa = 0.20571 m2 (Initially Ah was taken as 5 % of Aa but in that case the weeping criteria was not met)
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From the above graph, Weir length (lw) = 1.58m
Taking: weir height = 50mm Hole diameter = 5mm Plate thickness = 5mm
Check weeping
Maximum liquid rate = 7.37 kg/s Minimum liquid rate, at 70 per cent turn-down = 5.159 kg/s Lw,max 2/3 Maximum how =750x ( ρ l ) = 26.064mm liquid l w
Lw,min 2/3 Minimum how = 750x ( ρ l ) lw
= 20.55 mm liquid
At minimum rate hw + how = 50 + 20.55 =70.55 mm K2 = 30.5
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Uh (min) =
k2−0.9(25.4−dh) = 12.08 m/s ρ v 0.5
Actual minimum vapor velocity =
minimum vapor rate = 27.81 m/s Ah
Actual vapour velocity > minimum vapour velocity → Satisfied !!
Plate Pressure Drop Dry plate drop Maximum vapour velocity through holes uh = 27.5 m/s Orifice Coefficient = 0.795 uh 2 ρv H = 51x ( ) = 85.6052 mm liquid d C 0 ρl
Residual head hr =
12500 = 17.36mm liquid ρl
Total plate pressure drop ht = 152.96 mm liquid
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42
Downcomer liquid back-up
Downcomer pressure loss Take hap = hw – 10 = 40mm Area under apron, Aap = 40*3.675*10-3 = 0.0632m2 using Aap Lwl 2 = 166x ( ) = 4.35 mm Hdc ρl A m Back up in downcomer Hb = 233.374 mm liquid = 0.233 m ½ x (Plate spacing + Weir height) = 250 mm liquid So plate spacing is acceptable. Residence time tr = 2.26 x 0.225 x 785 / 19.82 = 9.24 s As tr is greater than 9.24 s hence satisfactory. Entrainment Uv = 2.47 m/s %flooding = UUn = 80.34 f
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43
So φ = 0.09 (well below 0.1)
Perforated Area
θc = 1000 Angle subtended = 1800 -1000 = 800 Mean length = 2.83 m area of unperforated edge strips
= 0.1415 m2
Mean length of calming zone = 1.63m Area of calming zone = 0.163 m2
Total area = Ap = 2.2665 m2 Ah Ap
Lp
= 0.0907 =2.9
Dh
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44
Area of each hole = 1.964x 10−5
Number of holes =
Ah = 10473 1.964x10−5
b. Distillation Column 3 Design Column Diameter Column Specifications:Feed (F): 73.91 mol/s Reflux Ratio (R): 1.77 Distillate Rate (D): 68.05 mol/s Bottoms Rate (B): 5.86 mol/s No. of real stages: 31
Flow rate Calculations:Rectifying section:V = D(1+R) = 68.50(1+1.177) = 188.49 mol/s L = D x R = 120.45 mol/s Stripping Section:L′m = L + liq part of F = 184.38 + 0 = 184.38 mol/s V ′m = V - vapor part in F = 188.49 - 10 = 178.5 mol/s
Calculation of Column Diameter: ρV F bottom = L′m = 184.38 x LV
V ′m
√
ρL
178.5
17.46
√
= 0.179
580.4
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45
F LV
top =
ρV
L
V
√
ρL
=
184.38 x 188.49
23.5
√
= 0.126
600.6
Taking plate spacing as 0.45 m
Base K1 = 0.034 Top K 1 = 0 .061
Base uf = K 1 Top uf = K 1
√ √
ρL − ρV ρV ρL − ρV ρV
√ = 0.061 x √ = 0.034 x
580.4 − 17.46 = 17.46
600.6 − 23.5 23.5
0.19 m/s
= 0.30 m/s
Where uf = flooding velocity Actual velocity = 0.8 x flooding velocity Base actual vel = 0.15 m/s Top actual vel = 0.24 m/s Net Area (base) =
Net Area (top) =
2 Max V apor volumetric f low rate = 1.985 m actual vel
2 Max V apor volumetric f low rate = 1.062 m actual vel
Taking downcomer area as 12% of the total, Total Area (base) A = Net Area c
0.88
2
= 2.256 m
Column Diameter (base) Dc = 1.695 m Total Area (top) A = Net Area c
0.88
2
= 1.207 m
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Column Diameter (top) Dc = 1.240 m As top diameter < bottom diameter Dc = 1.240 m
Provisional plate design Column diameter Dc = 1.69 m Column area Ac = 2.24 m2 Downcomer area Ad = 0.12 x Ac = 0.26 m2 Net Area An = Ac − Ad
= 1.97 m2
Active area Aa = Ac - 2Ad = 1.70 m2
Taking Hole area Ah as 10 per cent of Aa = 0.085 m2 (Initially Ah was taken as 5 % of Aa but in that case the weeping criteria was not met)
From the above graph, Weir length (lw) = 1.26m
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Taking: weir height = 50mm Hole diameter = 5mm Plate thickness = 5mm
Check weeping
Maximum liquid rate = 0.57 kg/s Minimum liquid rate, at 70 per cent turn-down = 6.914 kg/s Lw,max 2/3 Maximum how =750x ( ρ l ) =280.36 mm liquid l w
Lw,min 2/3 Minimum how = 750x ( ρ l ) lw
= 25.41 mm liquid
At minimum rate hw + how = 50 + 25.41 =75.41 mm K2 = 30.7
Uh (min) =
k2−0.9(25.4−dh) = 2.958 m/s ρ v 0.5
Actual minimum vapor velocity =
minimum vapor rate = 3.149 m/s Ah
Actual vapour velocity > minimum vapour velocity → Satisfied !!
Plate Pressure Drop Dry plate drop Maximum vapour velocity through holes uh = 4.499 m/s
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Orifice Coefficient = 0.805 uh 2 ρv H = 51x ( ) = 47.93 mm liquid d C 0 ρl
Residual head hr =
12500 = 21.54 mm liquid ρl
Total plate pressure drop ht = 144.88 mm liquid
Downcomer liquid back-up
Downcomer pressure loss Take hap = hw – 10 = 40mm
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Area under apron, Aap = 40*3.675*10-3 = 0.05m2 using Aap Lwl 2 ) = 9.274 mm Hdc = 166x ( ρl A m Back up in downcomer Hb = 229.57 mm liquid ½ x (Plate spacing + Weir height) = 250mm liquid So plate spacing is acceptable. Residence time tr = 2.26 x 0.225 x 785 / 19.82 =5.36 s As tr is greater than 3 s hence satisfactory. Entrainment Uv = 0.13 m/s %flooding = UUn = 0.43 f
So φ = 0.179 (well below 0.1)
Perforated Area
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θc = 1000 Angle subtended = 1800 -1000 = 800 Mean length = 2.288 m Area = 0.11 m2 Mean length of calming zone = 1.31m Area of calming zone = 0.131 m2 2 Total area = Ap = 1.458 m Ah Ap
= 0.058
Lp
=3.1
Dh
Area of each hole = 1.964x 10−5
Number of holes =
Ah = 4337.95 1.964x10−5
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c. Distillation Column 4 Design Column Diameter Column Specifications:Feed (F): 5.86 mol/s Reflux Ratio (R): 6 Distillate Rate (D): 0.756 mol/s Bottoms Rate (B): 5.103 mol/s No. of real stages: 40
Flow rate Calculations:Rectifying section:V = D(1+R) = 0.756(1+6) = 5.292 mol/s L = D x R = 4.536 mol/s Stripping Section:L′m = L + liq part of F = 4.536 + 5.759 = 10.395 mol/s V ′m = V - vapor part in F = 5.292 - 0 = 5.292 mol/s
Calculation of Column Diameter: ρV F bottom = L′m = 10.395 x V ′m
LV
F LV
top =
ρV
L
V
√
√
ρL
5.292
ρL
=
10.395 x 5.292
17.46
√
353.2
43.44
√
= 0.491
= 0.295
366.41
Taking plate spacing as 1.45 m
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Base K1 = 0.046 Top K 1 = 0 .056
Base uf = K 1 Top uf = K 1
√ √
ρL − ρV ρV ρL − ρV ρV
√ = 0.056 x √ = 0.046 x
353.2 − 17.46 = 17.46 366.41 − 43.44 43.44
0.17 m/s = 0.15 m/s
Where uf = flooding velocity Actual velocity = 0.8 x flooding velocity Base actual vel = 0.14 m/s Top actual vel = 0.12 m/s Net Area (base) =
Net Area (top) =
2 Max V apor volumetric f low rate = 0.119 m actual vel
2 Max V apor volumetric f low rate = 0.049 m actual vel
Taking downcomer area as 12% of the total, 2
Total Area (base) A = Net Area c
= 0.135 m
0.88
Column Diameter (base) Dc = 0.415 m 2
Total Area (top) A = Net Area c
0.88
= 0.049 m
Column Diameter (top) Dc = 0.25 m As top diameter < bottom diameter Dc = 0.25 m
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Provisional plate design Column diameter Dc = 0.41 m Column area Ac = 0.131 m2 Downcomer area Ad = 0.12 x Ac = 0.015 m2 Net Area An = Ac − Ad
= 0.116 m2
Active area Aa = Ac - 2Ad = 0.100 m2
Taking Hole area Ah as 10 per cent of Aa = 0.005 m2 (Initially Ah was taken as 5 % of Aa but in that case the weeping criteria was not met)
From the above graph, Weir length (lw) = 0.30m
Taking: weir height = 50mm Hole diameter = 5mm Plate thickness = 5mm
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Check weeping
Maximum liquid rate = 0.923 kg/s Minimum liquid rate, at 70 per cent turn-down = 0.646 kg/s Lw,max 2/3 Maximum how =750x ( ρ l ) =101.29 mm liquid l w
Lw,min 2/3 Minimum how = 750x ( ρ l ) lw
= 23.64 mm liquid
At minimum rate hw + how = 50 + 23.64 =73.64 mm K2 = 30.7\6
Uh (min) =
k2−0.9(25.4−dh) = 2.524 m/s ρ v 0.5
Actual minimum vapor velocity =
minimum vapor rate = 2.968 m/s Ah
Actual vapour velocity > minimum vapour velocity → Satisfied !!
Plate Pressure Drop Dry plate drop Maximum vapour velocity through holes uh = 4.24 m/s Orifice Coefficient = 0.805 uh 2 ρv H = 51x ( ) = 88.55 mm liquid d C 0 ρl
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Residual head hr =
12500 = 35.39 mm liquid ρl
Total plate pressure drop ht = 160.56 mm liquid
Downcomer liquid back-up
Downcomer pressure loss Take hap = hw – 10 = 40mm Area under apron, Aap = 40*3.675*10-3 = 0.012m2 using Aap Lwl 2 Hdc = 166x ( ρ A ) = 7.518 mm l m Back up in downcomer Hb = 241.72 mm liquid ½ x (Plate spacing + Weir height) = 250 mm liquid So plate spacing is acceptable.
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Residence time tr = 2.26 x 0.225 x 785 / 19.82 =1.52 s As tr is greater than 1.52 s hence satisfactory. Entrainment Uv = 0.046 m/s %flooding = UUn = 0.30 f
So φ = 0.0002 (well below 0.1) Perforated Area
θc = 980 Angle subtended = 1800 -1020 = 780 Mean length = 0.49 m Area = 0.02 m2 Mean length of calming zone = 0.357m Area of calming zone = 0.0357 m2
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2 Total area = Ap = 0.04 m Ah
= 0.125
Ap
Lp
=4.1
Dh
Area of each hole = 1.964x 10−5
Number of holes =
Ah = 255.31 1.964x10−5
REACTOR The feed components to the reactor are Urea and Methanol in the molar ratio of 1:20. The output stream from the reactor has methyl carbamate, methanol, dimethyl carbonate and ammonia in the molar ratio of 0.023, 0.89, 0.014 and 0.067 respectively. The operating conditions of the reactor are : T = 170 degree Celsius & P = 1 bar. At this temperature all the components are in gaseous state. Because of the low operating pressure and high temperature the gases are assumed to be ideal.
The output of the reactor and the input were related by the conversion data obtained from literature. Furthermore, the space time was obtained from a plot between mole fraction of DMC in output versus space time given in the literature.
Gas viscosities have been calculated as shown below while densities have been calculated using the equation : ρ=
PM RT
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μ =2.6693x10-5 √MT σ 2Ω M : Molecular Mass (kg/mol) σ : Characteristic diameter of molecule (A) Ω : Dimensionless constant μ : Viscosity (g/s.cm) T : Temperature (K) R : Universal gas constant
σ = 2.44( T Pc )0.33 c
T : Critical Temperature c Pc: Critical Pressure
ε kT
Ω is a function of
Components
. THe critical properties of various components are as follows :
Tc (K)
Pc(atm)
Methyl Carbamate
592.23
57.77
Methanol
513
78.5
Urea
638
76.34
DMC
557
147.13
Table 1 : critical temperatures and critical pressures
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Viscosity and density of the feed have been taken as the respective value of methanol since it is present in excess. The outlet stream viscosity and density has been calculated by multiplying viscosity and density of each component with its mole fraction.
Characteristic diameter Components
Ω
(Ȧ)
ε kT
Methyl Carbamate
5.30
1.0293
1.5735
Methanol
4.56
0.8916
1.6820
Urea
4.94
1.1089
1.5186
DMC
3.80
0.9681
1.6363
Table 2 : Ω & σ of various components
Components
Inlet mol fraction
Outlet mol fraction
Viscosity (Pa-s)
Density (kg/m3)
Methyl Carbamate
0
0.023
-6 11.008 X 10
2.0363
Methanol
029523
0.89
-6 11.81 X 10
0.881
Urea
0.0476
~0
DMC
0
0.067
-6 22.57 X 10
2.482
Table 3 : μ & ρ of various components
So the averaged viscosity and density of inlet and outlet streams are :
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Stream
Average viscosity (Pa-s)
Average Density (kg/m3)
Inlet
-6 9.092 X 10
881
Outlet
-6 8.69 X 10
0.866
Table 3 : μ & ρ of various streams
From literature, Space time τ = 0.3 kgcat h mol-1 Amount of catalyst (W )
cat Where τ is defined as τ = Feed molar f lowrate (F )
Hence Wcat = 0.3 X F = 398834.4 kg Wcat
Vcat = ρ cat
We are using ZnO pellets, both as the packing material as well as the catalyst ρcat = 5610 kg/m3 Wcat
Vcat = 5610 = 72 m3 Taking random packing density to be 62 % Volume of packed bed,
Vbed =
V cat = 116.1 m3 0.62
In order to ensure close temperature control, multi tubular fixed reactor was chosen
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61
All the reactor tubes were placed inside an enclosing shell with triangular pitch pitch was taken to be 1.25 times of diameter of individual tube (do) Number of total tubes that can be enclosed inside the enclosing shell was calculated using D n
Nt = K 1 (do b )1 where Nt = Total number of fixed bed tubes Db = Bundle diameter do = Diameter of individual fixed bed tube Using the above formula, following values were calculated after iterating for a multiple number of times, in order to obtain feasible reactor dimensions and keeping the constraint that πdo2 L 4
N t = V bed
where L = length of bed Using the above procedure following results were obtained, Two identical reactors would be placed in parallel with the following dimensions Db = 5 m do = 0.3 m NT = 132 L = 6.5 m
Pressure Drop Calculation Using Ergun’s Equation
ΔP L
=
150μ(1−ε2)v ε2 Dp 2
+
1.75(1−ε)ρv2 ε2Dp
ΔP : Pressure drop L : Length of each reactor column (m)
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μ : Fluid Viscosity (Pa-s) ε : void space of the bed V : superficial Velocity(m/s) Dp : Diameter of particle(m) ρ : Density (kg/m3) In our case : L = 6.5 m -6 μ = 8.85 x 10 Pa-s ε = 0.38 -4 V = net flow rate to each bed/ Area of bed = 7.67 x 10 m/sec Dp = 2 cm ρ = 873.5 (kg/m3) Calculating we get, ΔP = 2.08 Pa
Storage Facility BENZENE STORAGE TANK: Mass flow rate of Methanol = 2133.12 kg/hr Density = 792 kg/m3 Volumetric flow rate = 2.69 m3/hr Storage for 7 days (1 week) = 452.48 m3 Using standard dimensions from code:
[IS: 803-1976]
Height = 10.5 m Diameter = 7.5 m Volume = 463.57 m3
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UREA STORAGE TANK Mass flow rate of UREA = 3957.95 kg/hr Density = 1320 kg/m3 Volumetric flow rate = 2.99 m3/hr Storage for 7 days (1 week) = 503.73 m3 Using standard dimensions from code:
[IS: 803-1976]
Height = 4.5 m Diameter = 12 m Volume = 508 m3
FLASH Unit Specifications Feed: 32355.78 kg/hr (0.0156 m3/hr) Top Outlet (Vapor),V = 13110.67 kg/hr Density of V, ρv = 6.5 kg/m3 Bottom outlet (Liquid), L = 19245.11 kg/hr Density of L, ρL = 702.4 kg/m3
FLV = 15.26 ln(FLV) = 2.725 ρL − ρv ρv
Now permitted velocity, vperm = K
√
Where K =
+ C (ln F LV )2 + D (ln F LV )3 +
exp [ A + B ln F LV
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E(ln FLV )4 ]
64
In this equation, A, B, C, D and E are constants having the following values:-
A = -1.877478 B = -0.814580 C = -0.187074 D = -0.014523 E = -0.001015
Putting the values of FLV and these constants, K = 0.00292
Hence, vperm = K
D=
√
√
4 V π vpermρv
ρL − ρv ρv
= 0.03 m/s
= 4.86 m
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Now hv , related to the vapor velocity hv = 36” + hf = 12” +
1 diam 2
of feedline
1 diam 2
of feedline
L = h v + hf + h l
Now for nozzle diameter, umax =
100 √ρmix
, ft/s
umin =
60 , √ ρmix
ft/s
ρmix =
ρfeed = 578.19 kg/m3
umax = 4.16 ft/s = 1.27 m/s umin = 2.49 ft/s = 0.76 m/s
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Area of nozzle =
V olumetric f lowrate umin
=
0.0156 = 0.76
0.0205 m2
Dnozzle = 16.16 cm = 6.23 in ≈ 6.2 in
Hence, hv = 36 + 3.1 = 39.1 in hf = 12 + 3.1 = 15.1 in hl = 1 2( hv + hf ) = 27.1 in L = hv + hf + hl = 81.3 in = 2.06 m
Volume =
π D2 4
L = 38.23 m3
HEAT EXCHANGER HEAT EXCHANGER (B19) PROCESS DESIGN Design for number of tube, bundle diameter, shell diameter, tube side heat transfer coefficient (HTC), shell side HTC, Overall HTC and pressure drop for shell side and tube side (using Bell‘s Method). The values of all constants, tables and graphs have been taken from the book : Coulson Richardson’s Chemical Engineering Vol. 6 Chemical Engineering Design 4th edition. a) Properties of stream and HE layout specification Table : Properties of Hot Fluid Properties Values Stream Reactor outlet Inlet Temp Ti 170 Outlet Temp To 70 Mass Flow Rate 6626.39 Viscosity 1.28 x 10-4 1.86 Specific Heat Capacity, CP Density (vapor) 7.142 Thermal Conductivity 2.41 x 10-4 Table : Properties of Cold Fluid
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Unit ℃ ℃ kg/hr Pa.s kJ/kg-K kg/m3 W/m.K
67
Properties
Values
Unit
Stream Inlet Temp ti Outlet Temp to Mass Flow Rate Viscosity
Cooling Water 25 45 13413.12 8 x 10-4
℃ ℃ kg/hr Pa.s
Specific Heat Capacity, CP
4.178
kJ/kg.K
Density, ρ Thermal Conductivity, k
995 0.59
kg/m3 W/m.K
Step 1. Fluid Allocation : Shell side ( vapor) : Reactor outlet stream Tube side (liquid) : Cooling Water From mass and energy balance, Shell side mass flow rate, ms = 1.84 kg/s Tube side mass flow rate, mt = 3.72 kg/s Heat duty, Q = 311.33 kW
Step 2. LMTD Assuming counter current flow in a 1 shell 2 tube heat exchanger LMTD =
R=
∆T 1−∆T 2 1 ln ∆T ∆T 2
= 78.30 °C
(T i−T o) =5 (to−ti)
(to−ti) S = (T −t ) i i
= 0.14
From graph, FT = 0.965
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68
ΔTm,true =
True LMTD = FT x LMTD = 75.56 °C
Assumed overall heat transfer coefficient, Uass = 66.70 W/m2.℃
Q Area Required = A =
Uass∆Tm,true
= 61.77 m2
Choose tubes of following dimensions : 19mm OD, 16mm ID, 6.096m length effective length of straight tubes = 6.096 - 2 x 0.025 = 6.046 m Surface Area of one tube = 0.36 m2 Number of tubes =
Area Required Surface Area of one tube
= 172
Triangular pitch arrangement for the tubes has been used
Step 3. Tube side velocity Using 1.25do triangular pitch and split-ring floating head type and 2 tube pass. 1
Bundle diameter, Db = do ×
N ( K t )n1 1
= 0.37 m
Shell inner diameter, Di = Db + 0.053 = 0.42 m ( Di = Ds ) Number of tubes per pass, n = 86
(3.14 ndi2) Total flow area =
4
= 1.73 x 10-2 m2
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Velocity of water in tubes, ut =
mt (ρ x total f low area)
= 0.21 m/s
Step 4. Tube side heat transfer coefficient Method 1 : hi =
4200(1.35+0.02t)ut0.8
= 1454.25 W/m2-K
di0.2
Method 2 :
ρvdi Re = μ = 4309.51 Pr = µ
Cp k
= 5.66
L/di = 377.875 jh = 0.004
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70
k
h = ( f )j RePr 0.33 ( µ ) i
di
h
−0.14
µw
µ is assumed to be 1. µw Hence, hi = 1126.62 W/m2.K The minimum value is selected from both the methods. So, hi = 1126.62 W/m2.K Step 5. Shell side heat transfer coefficient lb = baffle spacing = 0.4 x Di = 0.17 m Tube pitch = pt = 2.38 x 10-2 m Cross flow area (As) =
(pt−do)lbDi = 1.41 x 10-2 m2 pt
ms Mass Velocity (Gs) = A = 130.12 kg /s.m2 s 1.10(pt2 – 0.917do2) Equivalent diameter, de =
Re =
do
= 1.34 x 10-2 m
Gsde μ = 137142.85
Pr = µ Cp k = 9.87
jh = 3.1 x 10-3
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71
k
f 0.33 2 hoc = ( do )j hRePr = 115.71 W/m -K
where hoc is the heat transfer coefficient calculated for cross-slow over an ideal tube bank, with no leakage and bypassing. Baffle cut, Bc = 25 % (assumed) Hb = height from the baffle chord to the top of the tube bundle Db = - D (0.5-B ) = 7.86 x 10-2 m 2
s
c
Ncv = the number of constrictions, tube rows, encountered in the cross-flow section Db−2Hb = 0.87p = 10.17 = 11 ( next integral value) t
Fn = tube row correction factor = 0.99
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72
Bundle cut, B =
Hb Db = 0.21
Ra’ = ratio of the bundle cross-sectional area in the window zone to the total bundle cross-sectional area = 0.14 Ra (at baffle cut) = 0.18
Nw = number of tubes in a window zone = R a’ x N = t 24.08 Rw = ratio of number of tubes in window zone to the total number in the bundle 2Nw = N = 0.28 t
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73
Nc = number of tubes in a cross-flow zone = Nt - 2Nw = 123.84 = 124 Fw = window correction factor = 1.08
Ab = clearance area between the bundle and the shell = lb(Ds-Db) = 8.91 x 10-3 m2 Ns = Number of sealing strips =3 Fb = bypass correction factor = exp (-
A
s 2/3 α Ab (1-( 2N ) )) = 0.87 N cv s
ct = diametrical tube-to-baffle clearance = 0.8 mm cs = baffle-to-shell clearance = 1.6 mm
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74
θb = angle subtended by the baffle chord = 2.1 rads Atb = tube to baffle clearance area, per baffle =
3.14ctdo(Nt−Nw) = 7.06 x 10-3 m2 2
Asb = shell to baffle clearance area, per baffle =
csDs(2x3.14−θb) = 1.41 x 10-3 m2 2
AL = Total leakage area = Atb + Asb = 8.47 x 10-3 m2 AL/As = 0.59 m2 βL = 0.37
FL = leakage correction factor = 1- β L (
Atb+2Asb AL
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) = 0.57
75
hs = hocFnFwFbFL = 61.31 W/m2-K Step 5: Overall coefficient
doln do 1 U
= h1o +
1 hod
+
di
2kw
+
do 1 di hid
+ ddo 1h
i i
U= 55.97 W/m2 oC where hod and hid are outer and inner dirt factors respectively. Error is less than 30 % , so the initial guess of overall heat transfer is current. Step 6: Pressure drop Shell side pressure drop jf = 4.5 x 10-2 ΔPi = pressure drop calculated for an ideal tube bank = F ’ = bypass correction factor for pressure drop = exp (-
8jf Ncvρus2 = 4342.03 Pa 2
α
Ab As
b
(1-( 2Ns )1/3)) Ncv
where ( α = 4) for Re > 100 Fb’ = 0.67 Ab/As = 0.63 βL′ = 0.6 FL’ = leakage factor for pressure drop = 1- β L ′
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(
Atb+2Asb AL
) = 0.30
76
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77
ΔPc = pressure drop in a cross − f low zone between the baffle tips, corrected for bypassing and leakage = ΔP i F b ′ F L ′ =
3.14Ds2Ra Aw = 4
-
868.03 Pa
3.14Nwdo2 = 1.82 x 10-2 m2 4
Nwv = number of restrictions for cross-flow in window zone, approximately equal to the
H number of tube rows = 0.87bp = 3.80 = 4 (round-off to next bigger integer) t uw = the velocity in the window zone, based on the window area less the area occupied by the tubes Aw =
ms = 14.18 m/s (Aw ρ)
uz = the geometric mean velocity = √uwus = 16.08 m/s ΔPw =
FL′(2 + 0.6Nwv)ρuz2/2
= 1186.98 Pa (Nwv +Ncv )
ΔPe = end zone pressure drop = ΔP i
Nb = number of baffles =
ef fective length lb
N cv
F ’ = 3971.20 Pa b
1 = 35.94 = 36
total shell side pressure drop = 2 ΔPe + (Nb − 1)ΔPe + Nb ΔPw = 6992.05 Pa
Tube side pressure drop Np = Number of tube passes = 2 jf = 6 x 10-3
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78
L
𝞓P = Np [8j ( )( t
f di
µ −m
)
+ 2.5]
µw
ρu2t 2
µ is equal to 1 ( assumed) µw 𝞓Pt = 963.03 Pa
MECHANICAL DESIGN OF REACTOR
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79
Data from process design: Shell inside diameter, Di = 5 m Column Parameters: Considering tray spacing = 0.45 m Height of shell = 7.5 m Operating pressure, P = 1 bars Design pressure = 105 kPa Selection of Materials: IS : 2002-1962 – Grade 2B , with double – welded butt joints (Ref : Table A – 1 , Pg 261, BCB) Calculation of Thickness: Thickness will be calculated using equation for low pressure vessel as pressure < 20 MN/m2 which assumes that the thickness, t, and internal diameter, Di ,ratio doesn’t exceed 0.25, which will be checked later .
PDi
t = 2f J −P f = 98.1 MN/m2 (Ref: Appendix A, Pg 261, BCB) J=1 Hence, t = 0.00267 m Corrosion allowance = 0.003 m So,Thickness standard = 0.007 m Do=Di + 2t = 5.014 m
Thickness of head: Torispherical Assuming Ri = Do= 5.014 m ri = 0.3, Do = 5.014 m
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ho = Ro – (( Ro – 0.5Do)(Ro + 0.5Do – 2ro))0.5 = 0.84 m Do2/4R o= 1.235 m (Doro/2)0.5 = 0.86 m Ho is least effective external height of head (hE) = 0.84 m J=1 t/Do =
P 2f J
C = 0.00177C
hE/Do = 0.169 From table, t/Do =0.0017 C = 3.21 t/Do = 0.0017 t = 0.0088 m Therefore, thickness = 12 mm t/Do ratio is less than 0.25. Hence, assumption is valid Hence, thickness = 12 mm Blank diameter = 5.41 m Height of flange = Sf =40 mm Stress calculation: Thickness = 0.0026 m Corrosion allowance = 0.003 m Top + bottom disengaging space = 1 m Insulation = 75mm asbestos Maximum wind velocity expected = 140 km/h Weight of each head = (πDb2ht sρ g)/4 = 129626.54 kg Axial stress due to pressure: σ zp =
PDi2
= 49.02 MN/m2
4t(Di+t)
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Axial stress due to dead loads: Wa = Wt. of shell for X meters length = (π D t X ϒins) N Ws
σ zs = Π D = ϒs X x 10-6 MN/m2 = 63563 kg t Assuming constant shell thickness, Wi = weight of insulation for a weight X meters = π Dins tins ϒins X x 10-6 MN/m2 = 49877.98 kg σ zi = Wi/ πDot = (tins ϒins X) /t = 1.18 MN/m2 σ zl = Wl/ πDt =54.03 MN/m2
Weight of ZnO = 403680 kg Hence weight of attachments is the sum of the three weights above (Wa)=413917 kg σ za = Wa/ πDot = 9.8 MN/ m2 Net stress, σ zw = σ za + σ zl + σ zs + σ zi = 11.34 MN/ m2 Stress due to wind loads: Wind pressures, Pw = 0.05 Vw2 = 980 N/m2 From table 9.1 BCB, maximum wind pressures is about 1000 N/m2 Hence Pw = 1000 N/m2 will be used K1 = 0.7 Calculation of K2 W = W s+ W i + W l + W a = 110.043 kN T = 6.35 x 10-5 (H/D)1.5(W/t)0.5 = 1.6 s > 0.5 s Hence K2 = 2 As height of column < 20 m, so wind load will not vary along the height of the column Pw = K1K2P1h1Do = 52.95 kN Bending moment
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Mw = PwH/2 = 197.06 kJ Resulting bending stress 4Mw
σ zsw = Πt(D +t)D =3.74 MN/m2 i i Design of skirt support: Important considerations Tensile stress in the skirt will be maximum when the dead weight is minimum i.e. the shell is just erected and the shell is empty without any internal attachment.The compression stress is yet to be determined when the vessel is filled up water for hydraulic test. Maximum wind load may be expected at any and this factor is always considered. Period of vibration: Minimum weight of vessels with two heads and a shell Wmain = π (Di + t) t(H-4) ϒs + 2 Wh Di = 1.73 m Wmin = 322.816 kN Wmax = 270.866 kN Tmin = 6.35 x 10-5 (H/D)1.5(Wmin/ta)0.5 = 2.42 > 0.5 Hence K2 = 2 (a coefficient to determine wind load) Wind load: The minimum wind load K, Pw = K1K2P1HDo Hence, Pw,min = 80.75 kN Pw,,max = 83.14 kN Wind Moment: Minimum wind moment Mw(min) = Pw(min) x H/2 = 302.07 kJ Maximum wind moment
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Mw(max) = Pw(max) x H/2 = 311.57 kJ As skirt thickness is assumed as I, So, Di = Do = 5.014 m σ zwm (min) = 4Mw(min)/ πD2t = 0.098/t MN/m2 σ zwm (max) = 4Mw(max)/ πD2t = 0.1225/t MN/m2 Tensile strength: Maximum tensile strength without any eccentric loads σ z,tensile = σ zwm,min - σ zw,min Substituting σz = f x J t = 0.042 mm Compression load σ z,max = σ zwm (max) + σ zw(max) Substituting Az(compressive) = 0.125 E (t/Do) t = 42 mm As per IS : 2825-1969 So, thickness of skirt plate = 42 mm
Design of skirt plate: Maximum compressive stress between bearing plate and foundation is: I = outer radius of bearing – outer bearing of skirt σ c = Wmax/A + Mw/z =0.23865/(2.71I - I2) + 0.277228/(2.71 - I)2I
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Assuming σ c= 2.74 MN/m2 I = 0.023 m So, I = 100 mm = width of bearing plate Thickness of bearing plate: Tbp = I(3 σ c/f)0.5 = 32 mm (approx.) So, a bearing plate of 32 mm thickness is used Stability factor: R = Do + 2I J = WminR/Mw = 3.44 (Skirt need not be anchored) Thickness of gusset plate = 0.014 m Number of gussets = 110 N x Pbolt = 0.322 Ar x n = 0.0067 Ar = 67 mm2 number of bolts = 101.22 = 108 bolts
HEAT EXCHANGER : Heat exchanger is assumed to be a cylindrical vessel under internal pressure. SHELL THICKNESS CALCULATION: Operating pressure = 1 bar Design pressure (P ) = 1.05 bar d
[From process Design] Material of construction: IS 1570-1961 15Cr9oMo55
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Design Temperature (T ) = 250 C o
o
f = 118 MN/m = 118 x 106 N/m
2
2
t=
pDi 2f J +p
[Ref: Eq. 3.3.19, BCB, 5 ED.]
Weld joint efficiency factor, J = 0.85
[Ref: Art. 2.8, Pg 20 BCB, 5 ED.]
t = 0.21 mm Corrosion allowance = 2mm Thus, thickness (t) = t + C.A = 2.21 mm = 5 mm (Std) [t/D < 0.25 thus assumption is valid] i
Thus, Outer diameter, Do = Di + 2t = 0.043 m
HEAD DESIGN: For the cylindrical design of exchanger, we have chosen Torispherical head because pressure is in range 0.1 - 1.5 MN/m . 2
D = 0.43m J=1
Taking head specifications as:
Ri = Do = Ro ri = 0.06 D = 0.025 m o
Sf = 40mm ho = Ro − [(Ro −
Do )(Ro 2
+
Do 2
− 2ro)]
0.5
[Ref: Eq. 4.2.22, BCB, 5 ED.]
ho 0.072 m D2o/4ro = 0.107 m
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Doro/2 = 0.074 m
Out of these three quantities calculated above, ho is the least. Therefore, ho = 0.107 m
he/Do = 0.169 J=1 p/2fJ = 0.000444
Trying out various values of t/Do from Table 4.1
t/Do = 0.0015 t = 0.00064 m = 0.64 mm
NOZZLES AND BRANCH PIPES:
Construction of nozzles: Shell nozzle: Material construction: Same as that of shell. f = 118 MN/m = 118 x 106 N/m 2
2
Shell wall thickness, ts = 0.05 m Corrosion Allowance (C) = 0.002 m dnozzle = 0.218 m
tr =
pDo = 0.00019 m 2f J +p
Area to be compensated (A) = (d + 2c )tr = 0.000042 m2
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Area available from shell (As) = (d + 2c)(ts – tr – C ) = 0.0106 m2 Area available from nozzle for reinforcement
tr′ =
pdo = 0.00011 m 2f J +p
H1 = [(d + 2C)(tn - C)]0.5 = 0.055 m An = 2H1(tn - tr’ - C) = 0.0015 m2
Area remaining to be compensated Area = A – (As + An) = -0.012 m2
Hence, no ring pad required.
Design of flange for opening:
Taking IS: 2004-1962 Class2: y = 25.5 MN/ m2
[Ref. Table 7.1, page 103 BCB, 5 ED.]
m = 2.75 Allowable Stress for Flange = 100MN/m2 Allowable stress of bolting material = 138 MN/m2 (Bolting material – 5% CRMO Steel) p = 1.05 MN/m2 d0 y−pm
=(
di
0.5
y−p(m+1))
= 0.85
Let di of gasket = 0.44 m do = 0.377 m Minimum gasket width (N) = (do-di)/2 = 0.011 m
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do (calculated) = di+ 2N = 0.46 m Basic Gasket seating width (bo) = N/2 = 0.0055 m Diameter at location of gasket load reaction G = di + N = 0.45 m
LOAD DUE TO DESIGN PRESSURE:
H = πd2p/4 = 1.697 MN
Load to keep joint tight under operation: Hp = πG(2b)mp = 1.675 MN
Total operating load: Wo = H + Hp = 1.677 MN Load to seal gasket under bolting up conditions, Wg = πGby = 0.19 MN So, Wo is controlling load. Minimum bolting area, Where, Ao = Am = Wo/So = 0.0057 m2 go = Shell thickness = 5 mm gi = 1.415 go = 7.075 mm C = ID + 2(gi + R) ID = B = 0.899 m
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M 30 x 2 is most suited (because difference in c is minimum) and hence selected.
Bolt diameter = 0.03 m No. of bolts = 12 Bolt circle diameter = 1.0068 m Flange outside diameter (A) = 1.0068 + 0.03 + 0.02 = 1.057 m Check of gasket width:
AoSo = 56.38 < 2y πGN
So, condition is satisfied.
FLANGE MOMENT COMPUTATION:
a) Operating Condition
Wo = W1 + W2 + W3 W1 = πB p/4 = 1.527 MN 2
W2 = H – W1 = 0.152 MN
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W3 = Wo – H = Hp = 1.67 MN
Selected lap joint flange a1= (C – B)/2 = 0.28 m a3 = (C – G)/2 = 0.27 m a2 = (a1 + a3)/2 = 0.28 m Mo = W1a1 + W2a2 + W3a3 0.4657 MJ Mo = Total flange moment
Bolting up condition:
Mg = Wa3 = 0.362 MJ M g < Mo Hence, Mo is controlling.
So, M = 0.46 MJ Calculation for flange thickness:
K = A/B = 2.45 Y = 1.
[Ref: figure 7.6, Pg 115, BCB, 5 ED.]
Assuming Cf = 0.1; t2 = (MCfY)/(BST) = 0.0025 t = 0.05 m Bs = πC/n = 0.2634 m Bolt pitch correction factor, Cf = [Bs/(2d+t)]0.5 = 0.15 Corrected flange thickness = t.Cf0.5 = 0.0767 m So, Final Flange Thickness = 85 mm
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MECHANICAL DESIGN OF DISTILLATION COLUMN
Data from process design: Shell inside diameter, Di = 1.73 m Column Parameters: Considering tray spacing = 0.45 m Number of trays = 31 Therefore 31 trays at 0.5 m spacing, and top and bottom engaging space 1 m each Bottom Separator Space = 2.75 m Length of column including skirt height = 18.45 m Operating pressure, P = 19 bars = 1900 kPa Design pressure = 199.5 kPa Selection of Materials: IS : 2002-1962 – Grade 2B , with double – welded butt joints (Ref : Table A – 1 , Pg 261, BCB) Calculation of Thickness: Thickness will be calculated using equation for low pressure vessel as pressure < 20 MN/m2 which assumes that the thickness, t, and internal diameter, Di ,ratio doesn’t exceed 0.25, which will be checked later .
t=
PDi 2f J −P
f = 98.1 MN/m2 (Ref: Appendix A, Pg 261, BCB) J=1 Hence, t = 0.0177 m Corrosion allowance = 0.003 m So,Thickness = 0.025 m Do=Di + t = 1.755 m
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Thickness of head: Torispherical Assuming Ri = Do= 1.78 m ri = 0.1038, Do = 1.78 m ho = Ro – (( Ro – 0.5Do)(Ro + 0.5Do – 2ro))0.5 = 0.301 m Do2/4R o= 1.4 m (Doro/2)0.5 = 0.3 m Ho is least effective external height of head (hE) = 0.3 m J=1 t/Do =
P 2f J
C = 0.01016C
hE/Do = 0.015 From table, t/Do =0.015 C = 1.605 t/Do = 0.015 t = 0.0267 m Therefore, thickness = 32 mm t/Do ratio is less than 0.25. Hence, assumption is valid Hence, thickness = 32 mm Height of flange = Sf =40 mm Stress calculation: Thickness = 0.017 m Corrosion allowance = 0.003 m Tray spacing = 0.5 m Top disengaging space = 1 m
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Bottom separator space = 2.75 m Weir height = 50 mm for all trays Downcomer clearance = 25 mm for all trays Insulation = 75mm asbestos Accessories: 1 caged ladder Maximum wind velocity expected = 140 km/h Tray loading = 25 lb/ft2 Weight of each head = (πDb2ht sρ g)/4 = 5799.63 kg Axial stress due to pressure: σ zp =
PDi2
= 48.55 MN/m2
4t(Di+t)
Axial stress due to dead loads: Wa = Wt. of shell for X meters length = (π D t X ϒins) N σ zs =
Ws Πt D
= ϒs X x 10-6 MN/m2 = 1.99 MN/m2
Assuming constant shell thickness, Wi = weight of insulation for a weight X meters = π Dins tins ϒins X x 10-6 MN/m2 = 43007 kg σ zi = Wi/ πDot = (tins ϒins X) /t = 0.439 MN/m2 Number of trays= 25 Weight of liquid, supported, Wl = (π/4t)Do2(0.05)(9.81) n x 10-6 MN = 5440 kg σ zl = Wl/ πDt =54.03 MN/m2
Weight of trays = ( πD2/4) x (1) x n x 10-3 MN = 72534 kg Hence weight of attachments is the sum of the three weights above (Wa)=86768 kg
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σ za = Wa/ πDot = 0.89 MN/ m2 Net stress, σ zw = σ za + σ zl + σ zs + σ zi = 0.288 MN/ m2 Stress due to wind loads: Wind pressures, Pw = 0.05 Vw2 = 980 N/m2 From table 9.1 BCB, maximum wind pressures is about 1000 N/m2 Hence Pw = 1000 N/m3 will be used K1 = 0.7 Calculation of K2 W = W s+ W i + W l + W a = 110.043 kN T = 6.35 x 10-5 (H/D)1.5(W/t)0.5 = 9.3 s > 0.5 s Hence K2 = 2 As height of column < 20 m, so wind load will not vary along the height of the column Pw = K1K2P1h1Do = 45.95 kN Bending moment Mw = PwH/2 = 424.06 kJ Resulting bending stress 4Mw
σ zsw = Πt(D +t)D = 9.87 MN/m2 i i Design of skirt support: Important considerations Tensile stress in the skirt will be maximum when the dead weight is minimum i.e. the shell is just erected and the shell is empty without any internal attachment.The compression stress is yet to be determined when the vessel is filled up water for hydraulic test. Maximum wind load may be expected at any and this factor is always considered. Period of vibration: Minimum weight of vessels with two heads and a shell Wmain = π (Di + t) t(H-4) ϒs + 2 Wh
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Di = 1.73 m
Wmin = 207.28 kN Wmax = 368.642 kN Tmin = 6.35 x 10-5 (H/D)1.5(Wmin/ta)0.5 = 9.9 > 0.5 Hence K2 = 2 (a coefficient to determine wind load) Wind load: The minimum wind load K, Pw = K1K2P1HDo For minimum weight condition, Do = 2.615 m For maximum weight condition, Do = 2.765 m Hence, Pw,min = 55.45 kN Pw,,max = 60.02 kN Wind Moment: Minimum wind moment Mw(min) = Pw(min) x H/2 = 55.07 kJ Maximum wind moment Mw(max) = Pw(max) x H/2 = 60.57 kJ As skirt thickness is assumed as I, So, Di = Do = 1.73 m σ zwm (min) = 4Mw(min)/ πD2t = 0.207/t MN/m2 σ zwm (max) = 4Mw(max)/ πD2t = 0.095/t MN/m2 Tensile strength: Maximum tensile strength without any eccentric loads
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σ z,tensile = σ zwm,min - σ zw,min Substituting σ z= f x J t = 0.0301 mm Compression load σ z,max = σ zwm (max) + σ zw(max) Substituting Az(compressive) = 0.125 E (t/Do) t = 34 mm As per IS : 2825-1969 So, thickness of skirt plate = 37mm
Design of skirt plate: Maximum compressive stress between bearing plate and foundation is: I = outer radius of bearing – outer bearing of skirt σ c = Wmax/A + Mw/z =0.23865/(2.71I - I2) + 0.277228/(2.71 - I)2I Assuming σ c= 25.6 MN/m2 I = 0.023 m So, I = 100 mm = width of bearing plate Thickness of bearing plate: Tbp = I(3 σ c/f)0.5 = 88 mm (approx.)
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So, a bearing plate of 88 mm thickness is used Stability factor: R = Do + 2I J = WminR/Mw = 0.36
Thickness of gusset plate = 0.043 m Number of gussets = 54 N x Pbolt = 0.207 Ar x n = 0.0043 Ar = 63 mm2 number of bolts = 69
3.4.d Design of auxiliary process equipment Pump Design Following data has been collected from Aspen plus software, for designing the pump system : Suction Pressure, P1 = 1 bar Discharge Pressure, P2= 30 bar Inlet fluid temperature = 32.75 oC Outlet fluid temperature = 33.51 oC Efficiency of the pump, η = 62.91 % Inlet fluid density = 755.164 kg/m3 Outlet fluid density = 755.081 kg/m3 Average fluid density, ρavg = 755.21 kg/m3 Volumetric flow rate of the fluid, v’ = 49.458 m3/hr.
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Head loss in the pump =
Power Intake =
(P 2−P 1)v′ = 3600η
P 2−P 1 9.81ρ avg.
38446.72 W
3.4.e Major engineering problems of the plant with their possible remedies. Problem — Carelessness or Unsafe Practices. In manufacturing, it is crucial that you and your team not grow complacent when it comes to workplace safety. In almost no other work environment is the risk of workplace accidents so high. The top three causes of injury and death in manufacturing are falling, being struck by an object, and electrocution — all preventable, if you know what to look for and take the proper prevention steps. The Fix — Constant Training and Inspections. Your workers should know safety procedures ranging from regular inspections to emergency response. They should be trained to spot anything out of the ordinary. Additionally, all of your equipment should be professionally inspected on a regular basis. Problem — Unrealistic Goals. It’s easy to be overly optimistic, especially if you believe you can win manufacturing business with an aggressive timeline. But many times, you’re setting yourself
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up to fail. Straining your workforce can actually be counterproductive by hurting morale and increasing the chances for mistakes. Unrealistic goals can set you up for bad business. The Fix — Detailed Project Management. In manufacturing, you must keep close track of your resources and manpower. Many facilities are migrating to different types of management software that allow you to see more than simply when your workers are clocking in and out. You can see how much time is needed for each task and plan future projects better. The result is a more consistent workload with realistic expectations. Problem — Planning Without Input. Planning a project takes collaboration and input from all involved. Failing to get feedback from your workers can result in heavy workloads that slow productivity. Further, if you fail to manage customer expectations, you could lose future business. The Fix — Planning Task Force. Your workers know better than anyone what can be done in a given amount of time and the best way to accomplish a task. Assign workers with varying expertise to give you feedback. Consult with them while you are still in the planning stage so that you can set more accurate expectations for your customers and to ensure that all needs can be met.
3.5. Material Storage and Handling Facilities Urea Physical state Vapor Density: 2.07 (Air = 1) Specific Gravity: 1.323 (Water = 1) Melting Point: 132.7°C (270.9°F) Saline Molecular Weight: 60.06 g/mol Water/Oil Dist. Coeff.: The product is more soluble in water;
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Solubility: Easily soluble in cold water, hot water. Physical state and appearance: Solid. (Crystals solid.) Odor: Almost odorless; May gradually develop slight odor of ammonia, especially in presence of moisture.
Storage and Handling Storage: Keep container(s) tightly closed. Use and store this material in cool, dry, well ventilated areas. Sore only in approved containers. Keep away from any incompatible material. Protect container(s) against physical damage.
Handling: The use of appropriate respiratory protection is advised when concentrations exceed any established exposure limits. Wash thoroughly after handling. Wash contaminated clothing or shoes. Use good personal hygiene practices. If used for the manufacture of feeds for livestock, mix thoroughly by making a pre-blend with one of the ingredients, then adding and mixing the preblend with all other ingredients.
Fire Fighting Measures Flammable Properties: Feed Urea 46% is non-flammable Flash Point-Not applicable OSHA Flammability Class-Not applicable LEL/UEL-Not applicable Autoignition Temperature-Not applicable
Unusual Fire & Explosion Hazards: Material will not burn. Undergoes thermal decomposition at elevated temperatures to produce solid cyanuric acid and release toxic and combustible gases (ammonia, carbon dioxide, and oxides of nitrogen). May explode when mixed with certain strong reducing substances (hypochlorites) - forms nitrogen trichloride which explodes spontaneously in air.
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Extinguishing Media: Use extinguishing agent suitable for type of surrounding fire. Fire Fighting Instructions: Positive pressure, self-contained breathing apparatus is required for all fire fighting activities involving hazardous materials. Full structural firefighting(bunker) gear is the minimum acceptable attire. The need for proximity, entry, flashover and/or special chemical protective clothing needs to be determined for each incident by a competent fire fighting safety professional. Water used for fire suppression and cooling may become contaminated. Discharge to sewer system(s) or the environment may be restricted, requiring containment and proper disposal of water.
First Aid Measures: Eye: If irritation or redness develops, move victim away from exposure and into fresh air. Flush eyes with clean water. If symptoms persist, seek medical attention. Skin: Remove contaminated shoes and clothing and cleanse affected area(s) thoroughly by washing with mild soap and water. If irritation or redness develops and persists, seek medical attention. Inhalation (Breathing): If respiratory symptoms develop, move victim away from source of exposure and into fresh air. If symptoms persist, seek medical attention. If victim is not breathing, clear airway and immediately begin artificial respiration. If breathing difficulties develop, oxygen should be administered by qualified personnel. Seek immediate medical attention. Ingestion (Swallowing): First aid is not normally required; however, if swallowed and symptoms develop, seek medical attention. Animal Antidote and Emergency Treatment: In animals, the cold water-acetic acid treatment may be useful. The adult cow is given 19 - 38 liters cold water and 3.8 liters of 5% acetic acid (vinegar) orally. This treatment limits absorption of ammonia from the rumen by diluting the rumen contents and slowing the rate of hydrolysis of urea by decreasing rumen pH and temperature. This treatment also promotes urine flow that, if maintained by fluid therapy, may assure recovery from urea toxicity. Gaseous or fluid bloat should be relieved before pumping water into the rumen. Consult your veterinarian immediately.
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Accidental Release Measures Urea is a feed ingredient and crop nutrient, however, large spills can harm or kill vegetation. ● Stay upwind and away from spill (dust hazard). ● Wear appropriate protective equipment, including respiratory protection, as conditions warrant ● Prevent spilled material from entering sewers, storm drains, other unauthorized treatment drainage systems, and natural waterways. ● Notify appropriate federal, state, and local agencies as may be required ● Minimize dust generation. ● Sweep up and package appropriately for disposal
Exposure Control/Personal Protection Engineering Controls: If current ventilation practices are not adequate to maintain airborne concentrations below the established exposure limits (see Section 2), additional ventilation or exhaust systems may be required. Respiratory: A NIOSH approved air purifying respirator with a type 95 (R or P) particulate filter may be used under conditions where airborne concentrations are expected to exceed exposure limits. Protection provided by air purifying respirators is limited (see manufacturer's respirator selection guide). Use a positive pressure air supplied respirator if there is potential for uncontrolled release, exposure levels are not known, or any other circumstances where air purifying respirators may not provide adequate protection. A respiratory protection program that meets OSHA's 29 CFR 1910.134 and ANSI Z88.2 requirements must be followed if workplace conditions warrant a respirator. Skin: The use of cloth or leather work gloves is advised to prevent skin contact, possible irritation and absorption (see glove manufacturer literature for information on permeability).
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Eye/Face: Approved eye protection to safeguard against potential eye contact, irritation, or injury is recommended. Other PPE: A source of clean water should be available in the work area for flushing eyes and skin. Impervious clothing should be worn as needed.
Stability and Reactivity Chemical Stability: Stable under normal conditions of storage and handling. Conditions to Avoid: Urea forms an explosive salt with nitric acid. Reacts violently with gallium perchlorate. Incompatible Materials: Not applicable in feed mill situation. Corrosivity: May be slightly corrosive to steel, aluminum, zinc, and copper. Hazardous Decomposition Products: Heating above 270.9°F (132.7°C) (decomposes to biuret, ammonia, cyanuric acid, and nitrogen oxides. Hazardous Polymerization: Will not occur.
Potential Health Effects Eye: Contact may cause mild eye irritation including stinging, watering and redness. Skin: Contact may cause mild irritation including redness and a burning sensation. No harmful effects from skin absorption are expected. Inhalation (Breathing): No information available. Studies by other exposure routes suggest a low degree of toxicity by inhalation. Urea dust may cause mild irritation of the nose, throat and respiratory tract. Ingestion (Swallowing): No harmful effect report by ingestion. Swallowing may cause irritation of the digestive tract. Signs and Symptoms: Effects of overexposure may include irritation of the nose, throat, respiratory and digestive tract, nausea, vomiting, coughing, and transient disorientation. Cancer: No carcinogenic effects in humans reported in the literature examined.
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Developmental: Inadequate data available to evaluate the developmental effects of this material. Other Comments: May be harmful to livestock if ingested without adequate mixing. If used for the manufacture of feeds for livestock, mix thoroughly by making a preblend with one of the ingredients, then adding and mixing the pre-blend with all other ingredients. Equivalent protein from Urea should not exceed 1/3 of the protein in the mixture.
Methanol Physical Data
Physical State: Liquid Appearance: Clear, Colorless Odor: Slight Alcohol Odor Molecular Wt.: 32.04 Boiling Point (760 mm Hg): 64.5°C Flash Point: 11 °C Auto Ignition Temp: 385 °C (NFPA 1978) Vapor Pressure @ 200 °C : 12.8 kPa Vapor Density: 1.11 (Air = 1) Viscosity: 0.55 cP (20 °C) % Volatile / Volume: 100.0 Freezing / Melting Pt.: -98 °C (-144 F) Water Solubility: Complete Soluble in: Water, Ethanol, Ether, Acetone, and Chloroform Partition Coefficient n-octanol/water: -0.82 / -0.66 Evaporation Rate: (BuAc=1) 5.9 (Ether = 1)5.3 Specific Gravity: 0.791 – 0.793 Saturation Concentration: 166 g/m
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Storage & Handling
Handling ● Wash hands thoroughly after handling. In the event of exposure, remove contaminated clothing and wash before reuse. ● Containers should be grounded and bonded when transferring material in order to avoid static sparks. ● Do not breathe vapor, mist or gas. Do not get in eyes, skin or clothing. ● Use non-sparking type tools and equipment,including explosion-proof ventilation. ● Empty containers retain product residue (liquid and/or vapor) and can be dangerous. ● Do not pressurize, cut, weld, braze, solder, drill, grind or expose such containers to heat, sparks,flame, static electricity or other sources of ignition. ● Keep container tightly closed.
Storage ● Keep away from heat, sparks, flames (all sources of ignition). Keep away from oxidizers,acids and bases. ● Store in a cool, dry, well-ventilated area away from incompatible substances. Outside or detached storage is recommended. ● Tanks must be grounded and vented and have vapor emission controls including floating roofs, inert gas blanketing to prevent the formation of explosive mixtures and pressure vacuum relief valves to control tank pressures. Tanks should be of welded construction and should also be diked. ● Do not store in aluminum or lead containers.(Anhydrous methanol is non-corrosive to most metals at ambient temperatures except lead and magnesium. ●
Coatings of copper and its alloys, zinc, or aluminum are unsuitable for storage as they are attacked slowly. Mild Steel is the recommended construction material for tanks.)
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● Plastics may be used for short-term storage, but not recommended for long-term use due to deterioration effects and the subsequent risk of contamination.
Fire Fighting Measures
Flash Point: 11°C Lower Explosive Limit: 6% (NFPA 1978) Upper Explosive Limit: 36% (NFPA 1978) Auto Ignition Temp.: 385°C NFPA 1978) Hazardous Combustion Products: Toxic gases and vapors; Oxides of Carbon and Formaldehyde. Extinguishing Media ● Small fires: Use dry chemical, carbon dioxide, water spray or alcohol resistant foam. Use water sprays to cool fire-exposed containers. ● Large fires: Use water spray, water fog or alcohol-resistant foam. Special Protective Equipment for Firefighters ● Firefighters must wear full face, positive pressure self-contained breathing apparatus, MSHA/ NIOSH (approved or equivalent), and full protective gear. ● Protective firefighting structural clothing may not offer complete protection from a methanol fire if there is liquid methanol or vapor levels above the threshold limit value (TLV). Use of HAZMAT suits are recommended.
Important Information Methanol burns with a clean, clear flame, which is almost invisible in daylight. Containers may build up pressure if exposed to heat and/or fire. Cool tanks / drums with water spray and remove them to safety. Fire fighting water should be contained if possible, as it is toxic and can cause environmental damage. Water runoff can cause environmental damage. Vapors can travel to a source of ignition and flash back. Material is lighter than water, and so a fire can be spread by
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the use of water. During a fire, irritating and highly toxic gases may be generated by thermal decomposition or combustion.Responders should stay upwind.
Accidental Release Measures Procedure ● Wear appropriate personal protective equipment as specified. ● Stay upwind. ● Ventilate area of leak or spill and isolate hazard area. ● Eliminate all sources of ignition. ● Keep unnecessary and unprotected personnel from entering the hazard zone. ● Contain and recover liquid where possible or dilute with water or use alcohol-resistant foam to reduce fire hazard. Collect liquid in an appropriate container or absorb with an inert material (e.g. vermiculite, dry sand, earth) and place in a chemical waste container. Do not use combustible materials such as sawdust. ● Use non-sparking tools and equipment. ● Do not flush to sewer and prevent from entering confined spaces. ● US regulations (CERCLA) require reporting spills and releases to soil, water and air in excess of reportable quantities.
Waste Disposal ● Recycling is the recommended disposal method. ● Incineration should only be performed using a legally approved incinerator fitted with emission controls. ● Methanol wastes are not suitable for underground injection. ● Biological treatment may be used for dilute aqueous waste methanol.
Exposure Controls / Personal Protection
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Engineering Controls: Use explosion-proof ventilation equipment. Use adequate general or local exhaust ventilation to keep airborne concentrations below the permissible exposure limits. Use only under a chemical fume hood. Facilities storing or utilizing this material should be equipped with an eyewash facility and a safety shower. Personal Protective Equipment ● Respiratory Protection: A respiratory protection program that meets OSHA’s 29 CFR 1910.134) and ANSI Z88.2 requirements or European Standard EN 149 must be followed whenever workplace conditions warrant a respirator use. ● Eye Protection: Use face shield and chemical flash goggles. ● Skin Protection: Rubber (Butyl or Nitrile) or neoprene gloves and additional protection including impervious boots, aprons, or coveralls as needed in areas of unusual exposure. PPE must not be considered a long-term solution to exposure control. PPE usage must be accompanied by employer programs to properly select, maintain, clean, fit and use. Consult a competent industrial hygiene resource to determine hazard potential and/or the PPE manufacturers to ensure adequate protection.
Stability & Reactivity Chemical Stability: Stable under normal temperatures and pressures. Conditions to Avoid: High temperatures, incompatible materials, ignition sources, oxidizers. Incompatible Materials: Avoid contact with strong oxidizers, strong mineral or organic acids and strong bases. Contact with these materials may cause a violent or explosive reaction. May be corrosive to lead, aluminum, magnesium and platinum. Hazardous Decomposition Products: Carbon monoxide, irritating and toxic fumes and gases, carbon dioxide, formaldehyde.
Hazards Identification Emergency Overview
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Vapor harmful. May be fatal or cause blindness if swallowed. Harmful if inhaled or absorbed through the skin. Flammable liquid and vapor. Causes irritation to skin,eyes and respiratory tract. Affects central nervous system and liver.
Target Organs: Kidneys, heart, central nervous system, liver, eyes.
Potential Health Effects Inhalation:An irritant to the mucous membranes. Toxic effects exerted upon nervous system, particularly the optic nerve. Once absorbed into the body, it is very slowly eliminated. Symptoms of overexposure may include headache, drowsiness, nausea, vomiting, blurred vision, blindness, coma, and death. A person may get better but then worse up to 30 hours later.
Ingestion: Toxic. Symptoms similar to those for inhalation, but severity and speed of appearance may be greater. May be fatal or cause blindness. Usual fatal dose: 100 – 125 ml. May cause gastrointestinal irritation with nausea, vomiting and diarrhea. May cause central nervous system depression, characterized by excitement, followed by headache, dizziness, drowsiness and nausea. Advanced stages may cause collapse, unconsciousness, coma and possible death due to respiratory failure.
Skin Contact:Methyl Alcohol is a defatting agent and may cause skin to become dry and cracked. Skin absorption can occur in harmful amounts; symptoms may parallel inhalation exposure.
Eye Contact: Irritant, characterized by a burning sensation, redness, tearing, inflammation, possible corneal injury, painful sensitization to light. Continued exposure may cause lesions.
Chronic Exposure: Marked impairment of vision has been reported. Repeated or prolonged skin contact may cause dermatitis. Chronic exposure may cause reproductive disorders and teratogenic effects. Laboratory experiments have resulted in mutagenic effects.
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Aggravation of Pre-Existing Conditions: Persons with pre-existing skin disorders or eye problems or impaired liver or kidney function may be more susceptible to the effects of the substance.
Other Highly flammable. May build up Electrostatic charges: risk of ignition. Vapor-Air mixture is flammable / explosive within the explosion limits.
National Fire Protection Association (NFPA) 704 Hazard Identification Rating Health:1
Other
Rating System
Reactivity:0
0 = No Hazard
Flammability:3
1 = Slight Hazard
Special Hazards:None
2 = Moderate Hazard 3 = Serious Hazard 4 = Severe Haza
First Aid Measures
Eyes Immediately flush eyes with an ample amount of water for at least 15 minutes, occasionally lifting upper and lower eyelids. Get medical help immediately. Skin Immediately wash skin with lots of soap and water for at least 15 minutes while removing contaminated clothing and shoes. Get medical aid if irritation develops or persists. Inhalation
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Remove from exposure to fresh air immediately. If breathing is difficult, give oxygen if available. If breathing has ceased apply artificial respiration using oxygen and a suitable mechanical device such as a bag and a mask. Ingestion The ingestion of methanol is potentially life threatening. Onset of symptoms may be delayed for 18 to 24 hours after digestion. If the victim is conscious and medical help is not immediately available, give 2 to 4 cupfuls of milk or water. Do not induce vomiting! Transport victim to a medical facility immediately. Note to Physician Effects may be delayed. Ethanol may inhibit methanol metabolism.
DMC Physicochemical properties Boiling point: 90 °C Density: 1.07 g/cm3 (20 °C) Explosion limit: 4.22 - 12.87 %(V) Flash point: 16.7 °C Ignition Temperature: 458 °C Melting Point: 0.5 - 4.7 °C Vapor pressure: 53 hPa (20 °C) Solubility: 139 g/l
Hazard Identification: 1. Flammable liquid 2. Keep away from heat, spark, and flame. 3. Keep container closed. 4. Use with adequate ventilation.
First Aid Measures:
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Inhalation: Remove to flesh air. If not breathing, give artificial respiration. If breathing is difficult, give oxygen. Skin: Immediately flush skin with plenty of water for at least 15 minutes while removing contaminated clothing and shoes. Splashes in eyes: Immediately flush eyes with plenty of water for at least 15 minutes while removing contaminated clothing and shoes. Ingestion: Immediately flush mouth, get medical attention.
Fire Fighting Measures: Suitable extinguishing media: Water spray, Carbon dioxide, Dry chemical powder. Special exposure hazards in a fire: It emits smoke and irritating fumes. Special protective equipment for a fire: Use a positive-pressure, self-contained breathing apparatus and full protective clothing.
Accidental Release Measure: Personal precautions: Wear respirator, goggles, boots and gloves. Methods for cleaning up: Absorb spill with inert material (e.g., dry sand or earth), then place in a chemical waste containers using non sparking tools. Flush residual spill with copious amounts of water. For large spills, dike for later disposal. Other instructions: Consult with local, state and country officials.
Handling and Storage Handling: Avoid contact with eyes, skins, and clothing. Wash thoroughly after handling. Storage: Store in cool dry place. Keep package closed. Keep away from heat, spark, and flame.
Exposure Controls/Personal Protection Special instructions for protection and hygiene: Safety shower and eye bath should be located in immediate work area. Provide general and/or local exhaust ventilations to control airborne levels below the exposure guidelines.
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Respiratory protection: Use an approved air respirator. Hand protection: Use heavy rubber gloves. Eye protection: Use chemical safety goggles. Skin protection: Use protective clothing impervious to this material. \
Stability and Reactivity Conditions to avoid: heated condition Materials to avoid: oxidizing agents. Hazardous decomposition products: Toxic fumes of monoxide, carbon dioxide.
3.6. Process Instrumentation and Control and Safety aspect Process Instrument Control The main goal of all the major units is to minimize the extent of undesirable processes and reaction. Quality control and the proper installation of an efficient process instrumentation and control system in the plant are two very important tools for monitoring this requirement. By use of instruments having varying degrees of complexity, the values of variables like, temperature, pressure, density, viscosity, specific heat, conductivity, PH, humidity, dew point, liquid level, flow rate can be recorded continuously and controlled within narrow limits. Process instrumentation and control aid the economic function of any operation by maintaining, improving and controlling the various process parameters like flow rates,
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temperature, pressure, level, composition etc. An efficiently controlled process plant system also ensures greater safety in its operation. The parameter measurement could be direct or indirect. Instrumentation and control systems must justify the additional investment in them. Process control must aid the smooth operation of the plant and show adequate returns in terms of greater productivity, quality and stability of the various processes and in producing the desired results.
Functions to be performed by the instrumentation system ● Indicating ● Recording ● Controlling The process control instruments should be capable of functioning under and withstanding the process conditions of temperature, pressure, chemical environment and other adverse conditions on the plant. It is advisable to set norms, standards and practices to ensure that the instruments are interchangeable, easy to maintain and install. Proper code must be followed. Other features could be ruggedness, accuracy and quick response. With respect to our plant, controls for the following variables may be required: Pressure: Pressure measurement systems including inductive, capacitive, and piezo-electric gauge, absolute and differential pressure; calibration of gauges; selection criteria and specifications; ISA symbols and case study. Level: Level measurement systems including resistance, capacitance, radiation and optical methods; selection criteria and specification; ISA symbols and case study. Temperature: Temperature measurement systems including platinum resistance, thermistors, thermocouples; pyrometers; selection criteria and specifications; ISA symbols and case study. Density and Flow: Flow measurement systems including venturi tube, orifice plate, magnetic flow meter, vortex meter, ultrasonic flow meter, Pitot-static tube, coriolis meter, mass flow meters; density measurement systems including vibrating element and radiological devices; selection criteria and specifications; ISA symbols and case study. Followings are the described various sensors available for controlling these parameters.
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Temperature control(subsection of above para) Temperature is a very common process variable and temperature control is critical to maintaining product quality and ensuring safe and reliable operation of many processes. There are mainly two devices that are most widely used for temperature measurement: ● Resistance Temperature Indicators (RTD's) ● Thermocouple Thermocouples are fabricated from two electrical conductors made of two different metal alloys. At one end of the cable the two conductors are electrically shorted together by crimping, welding, etc. This end of the thermocouple, the hot or sensing junction, is thermally attached to the object to be measured. The other end, the cold or reference junction is connected to a measurement system. Thermocouples generate an open-circuit voltage, called the Seebeck voltage that is proportional to the temperature difference between the sensing (hot) and reference (cold) junctions. Resistive Temperature Devices, a resistance-temperature detector (RTD) is a temperature sensing device whose resistance increases with temperature. An RTD consists of a wire coil or deposited film of pure metal whose resistance at various temperatures has been documented. RTDs are used when applications require accuracy, long-term stability, linearity and repeatability. RTDs can work in a wide temperature range; some platinum sensors handle temperatures from 165°C to 650°C.
Level measuring element (second para of subsection) There are two methods used to measure the level of a liquid: ● Contact Level Measurement ● Non-Contact Level Measurement Contact Level Measurement Contact level measurement, as the name implies, requires that the sensing element be in contact with material being measured. Continuous level measurements can be performed with: Direct Methods: With direct level measurement the sensor is in contact with the material over
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the entire span that we wish to measure. Direct contact continuous level measurement is commonly used in bulk powder storage silos and un-agitated tanks. RF capacitance/resistance level sensors are the typical direct contact level sensors for both the point and continuous level variety. Indirect Methods: With indirect level measurement the sensor is in contact with the material at a single point and the tank level is inferred from this point measurement. Pressure transmitters measuring hydrostatic head are typically used for indirect contact continuous level measurement.
Flow Measurement (third para of subsection) Flow meter is a device that measures the rate of flow or quantity of a moving fluid in an open or closed conduit. Flow measuring devices are generally classified into five groups. ● Differential Pressure meters: Fixed restriction variable head type flow meters using different sensors like orifice plate, venturi tube, flow nozzle, Pitot tube and Dall tube. ● Mechanical type flow meters: Quantity meters like positive displacement meters etc. ● Inferential type flow meters: Variable area flow meters (Rotameters), turbine flow meter target flow meters etc. ● Electrical type flow meters: Electromagnetic flow meter, Ultrasonic flow meter, mass flow meters, Laser Doppler Anemometers etc. ● Other flow meters: Purge flow regulators, Flow meters for Solids flow measurement, Cross-correlation flow meter, Vortex shedding flow meters, flow switches etc.
Distributed System for Process Control Earlier, plants were constructed with a distributed system in the sense that the individual controllers were located near the process equipment with which interacted. To control and adjust the operating parameter, operator had to go to each area consuming unnecessary resources. So, controllers were then started to be maintained in a single room so that operator could quickly assess the status of the process and make adjustments. The remote multiplexer is being further used. This unit consists of minicomputer and microprocessor. The process
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signals are scanned, converted to digital and transmitted to central computer located adjacent to the control room. So a single path is shared for all of these processes as against an individual signal path for each process. Based on the above mentioned parameters, automatic control has generally been accepted throughout the chemical industry. The resultant savings in labour combined with improved ease and efficiency of operations has more than offset the added expense for instrumentation. We have also used high speed computers as they serve vital tool in the operation of the plant. The primary objectives of the designer when specifying instrumentation and control schemes are: Safe plant Operation: ● To keep the process variables with in known safe operating limits. ● To detect dangerous situations as they develop and to provide alarms and automatic shutdown systems. ● To provide interlocks and alarms to prevent dangerous operating procedures. ● Production rate: To achieve the design product output. ● Product quality: To maintain the product composition with the specified quality standards. ● Profit: To operate the lowest production cost, commensurate with the other objectives.
IV. Environmental Protection and Energy conservation
4.1. Environmental Aspect The
International
Standards
are
based
on
the
methodology
known
as
Plan-Do-Check-Act(PDCA). PDCA can be briefly described as follows: ● Plan: establish the objectives and processes necessary to deliver results in accordance with the organization’s environmental policy. ● Do: implement the processes.
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● Check: monitor and measure processes against environmental policy, objectives, targets, legal and other requirements, and report the result. ● Acts: take actions to continually to improve performance of the environmental management system. Many organizations manage their operations via the application of a system of processes and their interactions, which can be referred to as the “process approach”. ISO 9001 promotes the use of the process approach. Science PDCA can be applied to all processes, to methodologies are compatible. This International Standards contains only those requirements that can be objectively audited. Those organizations requiring more general guidance on a broad range of environmental management system issues are referred to ISO 14004. This International Standards does not establish absolute requirements for environmental management.
4.1.a Air Pollution Storage Tank Emissions. Product storage tank emissions are controlled with double seal floating roofs or, in some cases, water scrubbers. Field experience indicates that a removal efficiency of 99% can be achieved with water scrubbing. Product Transport Loading. Emissions of product transport loading vents are gathered and sent to a flare or incinerator for VOC control. Destruction efficiencies of 98-99% are achieved using the flare and greater than 99% using incineration. Absorber Vent Gas. The absorber vent gas stream contains nitrogen, oxygen, un-reacted propylene, hydrocarbon impurities from the propylene stream, CO, water vapor, and small quantities of acrolein. The treatment of air emissions normally takes place on-site and usually at the point
of
generation. Waste gas treatment units are specifically designed for a certain waste gas composition and may not provide treatment for all pollutants. The petrochemical industry has increasingly reduced the emissions from point sources, and this makes losses from fugitive sources relatively more important.
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Petrochemical processes usually operate with closed process equipment because of reactant/product characteristics (e.g., high volatility, high toxicity, high hazard risk), and reaction conditions (e.g., high temperatures and pressures) and this has associated environmental benefits. Special fields of attention with regard to air emission prevention are: ● Raw materials and fuel composition; ● Required volume of process air; ● Presence of, and need for, inert gases in the process (e.g., N2 from ambient air); ● Energy consumption and the combustion conditions.
The major concern in atmospheric emissions from petrochemical complexes is emissions of VOCs. Release of toxic/hazardous components and their impact on plant surroundings needs special attention. The petrochemical industry is characterized by toxic / hazardous chemicals that are handled and processed in large volumes and so external safety is an important issue.
VOCs Emissions Control Generally the control on hydrocarbon emissions has been attempted by employing equipment design standards, control technologies and inspection/maintenance requirements. Improved technology has a great potential in fugitive emission control. In recent years, manufacturers of seals, packing, and gaskets for process equipment have designed their products to control fugitive vapour leaks. These more effective seals, packing, etc., are expected to result in lower emissions and lower costs for monitoring and maintenance programs. Hydrocarbon emissions can pose not only environmental risk but also safety risks. Indian petrochemical industries have been following inspection routine to ensure that any leaks do not lead to incidents. In such inspections sensory perceptions of the operators and LEL detectors play a vital role. This same program when extended with the use of monitoring instruments and appropriate frequency will lead to control of environmental risks and has been commonly called as Leak detection & Repair (LDAR). The effectiveness and costs of VOC prevention and control depend on VOC species, VOC concentration, the flow rate, and the source. Resources are typically targeted at high flow, high
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concentration, process vents, but recognition should be given to the cumulative impact of low concentration diffuse generation sources. Following table identifies the properties needed to select the appropriate control technique for each identified stream generated by a process source.
Process vents Process vents usually represent the largest source of VOCs generation from petrochemical processes. Wherever possible, VOCs should be reused within the process. The potential for recovery depends on: ● Composition: In technical and economic terms, a gas stream containing one VOC (or a simple mixture) will be more amenable to re-use than one containing a complex mix. Likewise, high concentration streams (with low levels of inerts) are more amenable to reuse. ● Restrictions on reuse: The quality of recovered VOCs should be of a suitable quality for re-use within the process, and should not generate new environmental issues. ● VOC value: VOCs that are derived from expensive raw materials will be able to sustain higher recovery costs.
The next best alternative is to recover the calorific content of carbon by using VOCs as a fuel. If this is not possible, then there may be a requirement for abatement. The choice of abatement technique is dependent on factors that include VOC composition (concentration, type and variability) and targeted emission levels. For example: ●
Pre treatment to remove moisture and particulates, followed by
●
Concentration of a dilute gas stream, followed by
●
Primary removal to reduce high concentrations, followed by
●
Polishing to achieve the desired release levels.
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The most frequent approach to point source control is the application of add-on control device. These devices can be of two types: combustion and recovery. Applicable combustion devices are thermal incinerators, catalytic incinerators, flares and boilers/process heaters. Applicable recovery devices include condenser, absorbers, and adsorbers. The combustion devices are more commonly applied control devices, since they are capable of high removal efficiencies for almost any type of toxic gases. Selection of applicable control technique is made on the basis of stream specific characteristics and desired control efficiency.
The choice of the best technique will depend on site-specific circumstances.
Storage Tanks:Emissions from storage tanks may contribute significantly to the total hydrocarbon emissions. The controls to be specified for each type of fluid, needs to be worked out preferably based on assessment of quantum of emissions, nature of hydrocarbons emitted (i.e., their toxicity) and the percentage reduction achieved by the controls.
Oil-Water Separators:Assessing the safety of control technologies is of paramount importance. Since the covering of API separators can potentially lead to explosive environment in the Oil Water separators, suitable safety measures need to be incorporated.
Fugitives Emissions Control Fugitive emissions to the air environment are caused by vapour leaks from pipe systems and from closed equipment as a result of gradual loss of the intended tightness. Although the loss rates per individual piece of equipment are usually small, there are so many pieces of equipment in a typical petrochemical plant that the total loss of VOCs via fugitive routes may be very significant. LDAR programmes are therefore important to identify leak sources and to minimise losses. Fugitive emissions can be controlled by elaborate leak detection, repair and equipment modifications. Many plants have implemented LDAR programmes in which various sources of
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fugitive emission like leaks from valves, flanges, pump seals, etc., are routinely monitored for leaks and maintained on regular basis.
4.1.b Liquid Effluent 4.1.b.1 Possible Sources The major sources of water pollution in our industry are: 1. Drains 2. Spills or leak 3. Metals
1. Drain: Drain of hot water into rivers or other location where infiltration may occur are harmful to living organisms.
2. Spills/leakages: Spill or leakage of any component i.e. ethylbenzene, styrene, methylene, ethylene are harmful to the environment and living organisms and are soluble in water. So, water washing treatment should be done immediately after spillage. and if, leakage is there in large quantities then, absorbent paper is used for absorbing the spill and then, water washing is done.
3.Metal: Metals may occur in effluents, for example, through the use of catalyst i.e.,Fe2O3. Metals generally need to be removed by separate treatment, because they cannot be removed efficiently in biological treatment plants.
4.1.b.2 Wastewater Prevention Technique 1. General prevention techniques Before considering wastewater treatment techniques, it is first necessary to fully exploit all the opportunities for preventing, minimizing and reusing wastewater. However, water use, effluent generation and effluent treatment are all intrinsically linked and should be considered in combination. A typical exercise in preventing wastewater may include the following steps:
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Step 1: Identify wastewaters - The first step is to identify all wastewater sources from a process and to characterize their quality, quantity and variability. An analysis is useful to identify those sources that use most water and contribute most wastewater. Further clarification is provided by the preparation of plans that show all drain networks, points of arising, isolation valves, manholes and points of discharge.
Step 2: Minimize water flows - The overall aim is to minimize the use of water in the process in order to obviate effluent production or, if that is not possible, to produce more concentrated effluents. It will be necessary to identify the minimum quantity of water that is needed (or produced) by each step of the production process and then to ensure that these requirements are implemented by such practices as: ● Use of water-free techniques for vacuum generation (e.g., use the product as a sealing liquid in vacuum pumps, use dry pumps) ● Employ closed loop cooling water cycles. ● Use management tools such as water-use targets and more transparent costing of water. ● Install water meters within the process to identify areas of high use.
Step 3: Minimize contamination - Wastewaters are created by contamination of process water with raw material, product or wastes; either as part of process operation, or unintentionally. The following techniques can prevent this contamination:
Process operation: ● Use indirect cooling systems to condense or cool steam phases (not direct injection systems) ● Use purer raw materials and auxiliary reagents (i.e., without contaminants). ● Use non-toxic or cooling water additives with lower toxicity (e.g., chromium
based
additives).
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From spills: ● Fit secondary containment to vessels and pipe-work that pose a high risk of leaks. ● Provide spill clean-up material (adsorbents, drain plugs, etc) at strategic points around the installation and prepare spill contingency plans. ● Use separate collection systems for process effluent, sewage and rainwater (although there may be cases where the blending of effluent streams offers treatment advantages).
Step 4: Maximize wastewater reuse - Even when wastewaters are produced/generated they do not necessarily have to be sent to a treatment plant.
2. Process Modification
In-plant processes All in-plant treatment options require segregation of process waste streams under consideration. If there are multiple sources of a particular pollutant or pollutants, it/they require segregation from the main wastewater sewer. However, similar sources can be combined for treatment in one system.
In-plant practices are the sole determinant of the amount of wastewater to be treated. There are two types of in-plant practices that reduce flow to the treatment plant. First, there are reuse practices involving the use of water from one process in another process. Second, there are recycle systems that use water more than once for the same purpose. Reduction in water usage sometimes may be more cost-effective in reducing the quantity of wastewater discharged than water reuse or recycle. Good housekeeping is one inexpensive method of wastewater reduction. Many of the wastewater streams are suitable for reuse within the plant.
Water quality Standards by CPCB
Solution
Permissible Limit
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TDS
850 mg/l
Suspended solids
350 mg/l
Nitrogen as N
85mg/l
Phosphorus as P
20mg/l
BOD5
300 mg/l
Alkalinity
200 mg/l
4.1.c Solid Disposal Waste Disposal Techniques Spent catalysts are generally sent back to the suppliers. Solid waste may be disposed by the following methods:
1. Landfill: Landfilling is the main method of disposal of municipal solid in most countries. Unlike incineration, landfilling is not capital intensive and does not require skilled laborers. Landfills dispose of municipal solid wastes directly, as well as the residue that remain after recycling, composting, and incineration. Regardless of the level of technology used, landfilling is very simple process waste is dumped into a disposal area where, depending upon the type of landfill, the material may be compacted, and covered with a layer of soil. Over time, organic wastes such as paper and food decompose to produce methane, carbon dioxide, water, organic acids and other chemicals. The rate of decomposition depends upon many factors including moisture content, pH, and temperature, degree of compaction, wastage and composition. When degradation occurs, the volume of the original waste is reduced, providing additional landfill capacity. Strong odors are emitted as the organic wastes decompose. Inorganic wastes such as metals and glass do not decompose, and remain essentially unchanged over time.
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2. Incineration: In the incineration process, wastes are burned at very high temperatures and byproducts are released into the atmosphere and concerned into incineration ash. The byproducts which are released into the atmosphere contain dust, acidic gases, vaporized metals, toxic chemicals such as dioxin, all of which have been linked to public health and environmental degradation. These byproducts can be reduced with a variety of air pollution technologies such as scrubbers which remove particulates before they are released into the atmosphere. The incinerator ash is highly toxic as it contains a high concentration of heavy metals, which stay in the incinerator while other wastes are burned, from batteries and other waste products.
4.1.d Noise Pollution Noise Pollution at Petrochemical Industries The large petrochemical plants and refineries are highly regulated concerns because of the materials and processes involved and their potential impact on nearby communities and the environment. In some jurisdictions a plant’s noise levels must be assessed when seeking regulatory permits and approvals for new facility construction, plant expansions or for the addition of new processes or equipment. Petrochemical faculties bring some unique noise and acoustical engineering challenges. Unlike most other industrial facilities, petrochemical processes operate largely outdoors, with the processing equipment located on open-frame steel structures. These operations which include pumps, compressors, blowers, agitators and coolers, run out in the open, with limited barriers in place to restrict equipment noise from carrying beyond the confines of the plant.
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Compounding this is the sheer size and scale of these operations, which incorporate a large and varied amount of stationary sound sources, along with miles of complex, intertwined piping systems. As a result, the noise levels generated by these facilities can often be significant. Identifying key, major contributors to the excesses within the plant labyrinth as measured from nearby community locations can be challenging. In general it is produced, at every stage in industry by various aspects like welding, drilling, running machinery, motors, operation of cranes, grinding, turning, forging, steaming, boiling, cooling, heating, painting, pumping, packing, transporting etc. It creates very serious of largescale noise problems that significantly affect the working people as well as surrounding people.
As mechanical noise is the major part of industrial noise and is due to machinery of all kinds and often increases with the type of operation and power capacity of the machines. The characteristics of industrial noise vary considerably depending on specific industrial process. High noise levels common in petrochemical industries can be due to presence of unsteady force and it’s structural elements caused by moving parts, vibration of heavy equipments, sound from engines, gear, bearings, rotating and reciprocating machines, combustion, fans, pressurized flow, during shifting of raw materials and end products, trucks and dumpers etc.
For Petroleum industries the noise pollution may generate at any phases of development including: ● Seismic Operations ● Construction Activities ● Drilling & Production ● Aerial Surveys ● Transportation.
4.2. Energy Conservation
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With the rising population of the world and rapidly increasing per capita consumption in the developing countries, energy conservation has become the focus of attention all around the world, particularly in energy intensive petrochemical industry. The fast depleting petroleum resources, which are estimated to be just around 89*10^9 barrels as reserves (sufficient for just another 30 years) have led to the exploration of new energy resources. In this context, both conventional and nonconventional sources of energy are to be studied.
7.2.1 Alternate Energy Resources Renewable energy resources have become more important now a day in process plants. The major renewable energy forms and their present use and prospects have been tabulated below.
Solar Energy Electrical/ thermal conversion of solar energy in which electricity is generated using solar concentrating mirrors, absorbers and high temperature thermodynamic cycle can be used for both industrial and domestic use. In industry, much of the energy required is used for relatively low temperature applications such as space heating, dehydration of food, heating water for production and processing of low pressure steam.
Biomass Conversion Heat, fuel, electricity or chemical feed stocks undergo cultivation and chemical processing under the action of terrestrial and aquatic plants. Other sources from which energy can be derived include industrial. Agriculture, human and animal wastes. The final products of these processes may be methane, ethylene, hydrogen, alcohol, heat, steam, charcoal, other solid fuels and synthetic oils.
Wind Energy Wind is utilized to propel turbines and air foils, which convert it to electrical or mechanical energy. A 3.5 m diameter rotor develops about 0.16 BHP in a 15-mph wind can pump to 35 gallons of water per minute to a height of about 10 cm.
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Tidal Energy Ocean thermal energy conversion into electricity is another possible source of energy. This is due to fact that oceans are the largest solar collectors and storage system. We can also make use of thermal gradients that exists beneath the water surface and derive heat from these.
Nuclear Energy More than 1900 tons of uranium reserves are presents in the earth. Given proper measures, this form of energy is very competitive and an excellent substitute for fossil fuels. However, this form of energy is viewed with some reservations due to the inherent hazards of radioactive pollution.
7.2.2 Energy Conservation Measures The increasing cost of primary fuel has broadened the range of the heat recovery applications that can be economically justified. In a typical chemical concern with a profit margin of Rs. 4 per Rs. 100 sales, a saving of Rs. 1 in energy cost is approximately equivalent to an increase of Rs. 25 in sales. The entire gamut of energy conservation operations can be classified into two broad categories: 1. Energy Concept: The term energy has its origins in last of thermodynamics. It can be redefined in terms of enthalpy or entropy change or temperature difference. In each process, the sum of all the inputs are always greater than the sum of all the outputs, the differences being the energy losses. The endeavour of all energy conservation step is to minimize this energy loss. 2. Pinch Concept: Every chemical industry used hot and cold streams. The hot streams are cooled while the cold streams get heated up. These are called the hot and cold end “Approach”. ΔT, i.e. the temperature difference between the hot and cold end need not remain same through the temperature range. In a grand composite curve, all the hot and
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cold streams are combined to form the hot composite and cold composites respectively. There is a situation when ΔT becomes minimum. This point of closest approach is called pinch of the integrated heat exchanger (HEN) and signifies zero heat transfer in the grand composite curve.
To achieve energy conservation, the following three rules must be followed: ● No heat transfer across the pinch ● No cooling above the pinch ● No heating below the pinch Apart from the above, some more measures taken for the energy conservation are: Boiler & Steam systems Increase the efficiency of the condense system Replace improperly sized steam traps Upgrade the quality of insulation in the plant Reuse the hot water stream previously served
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V. Plant Utilities
The word "Utilities" is now generally used for the ancillary services needed in the operation of any production process. These services will normally be supplied from a central site facility; and will include: 1. Instrument Air 2. Electricity. 3. Steam, for process heating. 4. Cooling water. 5. Water for general use. 6. Demineralized water. 7. Compressed air. 8. Inert-gas supplies. 9. Refrigeration. 10. Effluent disposal facilities Secondary utilities: 1. Maintenance facilities 2. Roadways 3. Rail/road facilities 4. Fire protection
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5. Plant sewer system and waste disposal 6. Plant buildings 7. Plant security
5.1. Air for Process and Instrumentation For plant utilities we use secondary measuring instruments. These are the elements of a measuring information system that indicate or record the values of the quantities being measured. There are various modifications of secondary measuring instrument: single channel types (which indicate or record); multi-channel types (which simultaneously indicate and record the values) etc. The most important part of any secondary measuring instrument is the energy-generation and energy transmission systems which used to relay the signals. In the pneumatic system, the energy generating facility is composed of an air compressor, air dryer and storage tank. Pneumatic secondary instruments rely on the slight movement of flapper nozzle mechanism to sense signal change. Therefore clean dry air must be provided to ensure proper operation. The air is typically supplied throughout the plant in ½ inch (12 mm) pipes and at 40-60 psi. This pressure is reduced to a standard 20 psi for operation of each pneumatic instrument. Pneumatic signals are usually transmitted through tubing, usually ¼ inch (6mm) from feed to control room and within the control room between instruments. In the generation of compressed air there are two main equipment: 1. Air receivers: A small tank is provided after the compressors in the installation of compressor which is known as air receivers. An air receiver serves a fourfold purpose. ● As a surge tank to damping the pulsation of air delivered by the compressor. ● It is used as cooler. ● As a storage vessel of air. ● Removal of the oil and moisture contained in the air.
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2. Air compressors: Compressors have numerous forms, the exact configuration being based on the application. There are two basic modes: a) Intermittent: - This mode of compression is cyclic in nature, in that a specific quantity of gas is ingested by the compressor, acted upon, and discharged before the cycle is repeated. This type of compressor is also referred by positive displacement compressors, of which there are two distinct types; reciprocating and rotary. b) Continuous:- This mode is one in which the gas is moved into the compressor, is acted upon, moved through the compressor, and discharged without interruption of the flow at any point in the process. Continuous-mode compressors are also characterized by two fundamental types: dynamic and ejector. In our case both instrumentation and process air are required. All pneumatic controls in the plant require instrument air which is supplied in air compressor house. A slight malfunctioning of this unit may result in complete failure of all the units. The piping is over designed and extreme care is taken to prevent piping failure.
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5.2. Heat Transfer Media Heat transfer media are defined as fluids which absorb and provide thermal energy to the process equipment. Properties of heat carriers: (i) High rate of heat exchange (ii) Absence of corrosion effects (iii)Cheap and easily available (iv)Low viscosity (v) Non-toxic (vi) Non-inflammable and thermally stable The heat transfer media being used in our plant is: Steam Steam offers the following advantages over the other heat carriers: (i) It is thermally stable over the entire range of operation. Also it has less corrosive effects. (ii) Water is the cheapest and most commonly available heat carrier. Reasons for choosing steam ● Steam has many important advantages such as high latent heat, constant temperature requiring practically no control, easy production from commonly available water, high value of heat transfer coefficient during condensation, no special problems in handling and transportation. However, its use is generally restricted to about 220°C because of its low critical temperature. ● High pressure steam is a costly affair as it requires boilers and other processing and handling equipment to be at high pressure. ● Recently a concept of cogeneration in which high pressure superheated steam is used in turbines for power generation has picked up. ● The exhaust of turbine is used for thermal heating.
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● Now a days, the exhaust steam available at a low pressure of 1.5 – 2 atm being used as a supplement to process steam of high pressure.
5.3. Water Use of raw water: A plant water supply is separated into process, cooling, potable, fire water and utility water systems. Brief descriptions of the different water uses in industries are given below. Process water: water is typically used for various purposes where the water is closely contacted with the reactants. Softened water is usually used for these purposes. Cooling water: Water-cooled condensers, product coolers (heat exchangers) and other heat exchangers can use a large amount of water in a plant. Some industries use air coolers, where the process stream is exchanged with air prior the being sent to a cooling water heat exchanger. This will minimize the use of cooling water in the industry. Potable water: Potable water is required for use in kitchens, wash areas and bathrooms in plants as well as in safety showers/eyewash stations. City water or treated groundwater can be used for this purpose. In remote locations or in small towns a portion of the treated water from the plant softening unit may be diverted for potable water use. The treated water must be chlorinated to destroy bacteria, and then pumped in an independent system to prevent potential crosscontamination. Potable quality water may also be required in some specialist chemical operations (e.g. as a diluent). Fire water: The requirements for fire water in industries are intermittent, but can constitute a very large flow. Often, industries collect stormwater from non-process areas and store it in a reservoir dedicated to the fire water system in the plant. Provisions are typically made for a connection (for use in emergency situations) of the fire water system into the largest available
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reservoir of water. Usually this is the raw water supply since fire water requires no treatment. Seawater or brackish water is often used as fire water by plants located along coastal areas. Utility water: Utility water is used for miscellaneous washing operations, such as cleaning an operating area. It should be free from sediment but does not require any other treatment.
Raw water treatment: The raw water treatment in a industry creates wastewater and sludges that require disposal. The following section describes the best practices with respect to these discharges. Raw water treatment—best practices ● Lime softening: When lime softening is used for raw water treatment, the sludge generated in this process should be thickened, and optionally dewatered. The thickener overflow water can be discharged directly without any further treatment, when local regulations allow. The sludge that is generated should be disposed off-site. Not discharging it to the sewer in the refinery will prevent the introduction of inert solids into the sewer in the industry which in turn will avoid creation of more oil sludge that requires disposal. ● Ion exchange: The use of ion exchange for treatment of raw water creates an alkaline wastewater stream and an acidic wastewater stream as a result of the regeneration of the ion exchange beds. These streams should be collected in a tank and the pH neutralized prior to being discharged directly to an outfall (bypassing wastewater treatment) if allowed by local regulation. ● Reverse osmosis: The use of reverse osmosis for raw water treatment results in the creation of a reject stream that is very high in dissolved solids. This reject stream should be discharged directly to an outfall (bypassing wastewater treatment) if allowed by local regulation. Water Storage: Water Storage Facilities serve multiple purposes within a distribution system. The main purposes of finished water storage: • Equalizing supply and demand • Increasing operating convenience
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• Leveling out pump requirements • Decreasing power costs • Providing water during power source or pump failure • Providing large quantities of water to meet fire demands • Providing surge relief • Increasing detention times • Blending water sources There are many styles and construction materials for storage facilities. Selection of type and construction material is generally based on hydraulic considerations and cost. Storage facilities, depending on design can provide direct access to treated water as in open reservoirs or through hatches and vents as in closed reservoirs. Buried reservoirs are also susceptible to groundwater intrusion; however, this is not a viable means of intentional contamination. Depending on the size and design of the distribution system, finished water storage reservoirs can present a single point of failure or contamination or, to a lesser extent, disruption or contamination to particular portions of the service area. Historically, storage facility location has been driven by hydraulic needs, not security needs. Security needs have been of minor concern.
Cooling Tower Design Conditions: Cooling towers are heat removal devices used to transfer process waste heat to the atmosphere. Cooling towers may either use the evaporation of water to remove process heat and cool the working fluid to near the wet-bulb air temperature or in the case of "Close Circuit Dry Cooling Towers" rely solely on air to cool the working fluid to near the dry-bulb air temperature. Common applications include cooling the circulating water used in oil refineries, chemical
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plants, power stations and building cooling. The towers vary in size from small roof-top units to very large hyperboloid structures that can be up to 200 metres tall and 100 metres in diameter, or rectangular structures that can be over 40 metres tall and 80 metres long. Smaller towers are normally factory built, while larger ones are constructed on site. They are often associated with nuclear power plants in popular culture.
Cooling Towers: Operating Principle Cooled water is needed for air conditioners, manufacturing processes or power generation. A cooling tower is an equipment used to reduce the temperature of a water stream by extracting heat from water and emitting it to the atmosphere. Cooling towers make use of evaporation whereby some of the water is evaporated into a moving air stream and subsequently discharged into the atmosphere. As a result , the remainder of the water is cooled down significantly. Cooling towers are able to lower the water temperature more than devices that use only air to reject heat , like the radiator in a car , and are therefore more cost –effectiveness and energy efficient.
A cooling tower is determined by the properties with the following parameters. ➢ CT inlet temperature and CT outlet temperature ➢ Wet bulb temperature and Dry bulb temperature ➢ Water flow rate
Dry bulb temperature of air entering the cooling tower of any affect the amount of water evaporated. This temperature also affects the flow of hyperbolic towers and dry weather in any indirect-contact cooling tower element affects the working position. Use of air conditioning cooling tower thermal capability of a 1.25 per kW of heat dissipation base of evaporative cooling is expressed in terms of nominal capacity. Nominal cooling capacity of 25 to 6 ° C inlet air wet bulb temperature, 54 ml / s, water temperature 35 ° C is defined as 29 5 ° C to reduce the required cooling. 1.25 per kW / kW evaporator capacity of these circumstances, cooling tower
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heat throws. These values are based on traditional assumptions and inferences conditions typical air-conditioning evaporator taken every kilowatt of heat for 'cooling tower 0, 25 kW or remove the heat of an additional compressor. Values of the nominal capacity of the tower is not used for special applications and specific operating conditions are generally thermal performance capability of the air entering wet bulb temperatures entering and leaving water temperature, water flow rate is expressed in the basis.
5.4. Refrigeration Efficient industrial refrigeration systems are developed through proper design, the use of premium efficiency equipment, and the installation of appropriate system controls, as well as regular maintenance. Energy costs are a significant expense for these businesses. For example, approximately 25% of the electricity consumed by the food processing industry is used for process cooling and refrigeration. Nevertheless, despite the high energy costs associated with refrigeration and the potential savings from increased efficiency, the historical focus on designing and installing new refrigeration equipment hasbeen to develop systems that can meet a facility’s energy load at a minimum capital cost. Energy use and operating costs have had a lower priority.
Refrigeration systems are designed to achieve and maintain the specific required conditions of a facility’s refrigerated space by producing enough cooling to overcome the heat added by external and internal loads as well as the heat generated by the product. Refrigeration systems usually comprise four major components—compressor, condenser, expansion device, and evaporator— which are shown in Figure. Several equipment types and technologies are available for each of the major components; in many cases, each system component comes from each of the major components; in many cases, each system component comes from a different manufacturer. To maximize the overall efficiency of a refrigeration system, it is important to consider the interaction among components as well as the individual performance of each. Following is shown a diagram representing a basic refrigeration system:
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Figure: Basic Refrigeration Cycle Various types of refrigerants exist, but many of them are being phased out due to increased regulation. Refrigerants usually fall into one of the following groups:
CFCs – chlorofluorocarbons HCFCs – hydrochlorofluorocarbons HFCs – hydrofluorocarbons HCs – hydrocarbons NH3 – ammonia
CFCs have been widely used in the past but are now phased out of production due to their high ozone-depleting potential (ODP). HCFCs also have ODP; they are strictly regulated and are in the process of being phased out. HFCs and HCs have zero ODP and are being used as replacements for refrigerants with ODP. Ammonia is toxic but has no ODP and is used extensively in industrial refrigeration systems. Several advantages of ammonia have contributed to its popularity in industry, including high latent heat and therefore less required mass flow, low pressure losses in connecting piping, and low reactivity with refrigeration lubricants.
Following is provided an overview of common energy efficiency measures, specifically: Optimized compressor sequencing Moderately oversized condensers Floating head pressure control
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Increased suction pressure Variable frequency driver Premium efficiency motors Demand-based defrosting Insulation High-efficiency lighting fixtures and controls Rapid-closing doors
5.4. Electricity and Power
Equipment
Power
Week
Total
Consumptio
y
Weekly
Annual
Number of
Total
n instrument
Usage
consumpti
Consumpt
Equipments
Annual
(W)
(h)
on(kWh)
ion(kWh)
or people
Power(kW)
Computer Box
72
43.2
3.456
179.712
112.5
22464
Laptops
18
43.2
0.864
44.928
90
4492.8
Document Shedder
450
4.5
2.25
117
9
1170
Projector
135
4.5
0.675
35.1
9
351
36
151.2
6.048
314.496
9
3144.96
17.19
893.88
10.8
10726.56
Computer Network/Hub printer/copier/fax machine coffee maker mobile phone charger
374.4
9
3.744
194.688
18
3893.76
3.6
9
0.036
1.872
90
187.2
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Telephones/ intercom
151.2
65.7
3375
100.8
378
Ventilation System
36
151.2
6.048
Fans
36
100.8
HVAC
Lifts
3416.4
180
683280
0.9
19656
315
6.3
2205
4.032
209.664
450
104832
391.5
24429.6
5.4
146577.6
Lighting(max. i.e 35% of
the
total
energy
consumption)
49.5
45
2.475
128.7
900
128700
Vacuum Cleaners
1350
13.5
20.25
1053
5.4
6318
Microwave
1260
9
12.6
655.2
1.8
1310.4
fridge/freezer
187.2
151.2
31.4496
1635.379
1.8
3270.758
water Heater
81
54
4.86
252.72
10.8
3032.64
Hand drier
421.2
32.4
15163.2
Dish Washer
299.7
1.8
599.4
1084.5
72
86760
CCTV System
54
151.2
9.072
Plant Equipments and others
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VI. Organizational Structure and Manpower Requirement
Grade
Gross salary (per month in Rs)
A0
2,00,000
A1
1,50,000
A2
1,00,000
A3
70,000
A4
50,000
A5
18,000
A6
8,500
B0
50,000
B1
20,000
B2
6,000
Designation
Minimum Education qualification
Number
Grade
President
BTech+MBA with at least 20 years experience
1
A0
Vice President
BTech+MBA with at least 15 years experience
2
A1
General Manager Medical Officers
BTech+MBA with at least 12 years experience
2
A3
Legal Head
LLB
1
A3
Security Head
Retired army officer
1
A3
Administration
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Fire and Safety Head
Graduate (B.A)
1
A3
Fire Man
Diploma
5
A6
Medical Staff
Diploma
4
A6
General Manager
BTech+MBA with at least 12 years experience
1
A2
Staff
Graduate
4
A5
General Manager
CA with 10 years of Experience
1
A2
Accountants
M.com
4
A4
General Manager
BTech+MBA with at least 12 years experience
1
A2
Managers
BTech(chemical)
4
A4
Shift Engineers
BTech(chemical)
12
B0
Operators
BTech(chemical)
16
B1
Labor
BTech(chemical)
30
B2
General Manager
BTech(chemical) with 5 years experience
1
A2
Engineers
BTech
10
B0
Staff
Graduate
12
B1
BTech(chemical) with 5 years experience
1
A3
Personal (HR)
Finance
Production
Technical
Maintenance Senior Manager
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Engineer
BTech(chemical) with 3 years experience
2
A4
Operator
Diploma
6
B1
Labor
High School
10
B2
Total salaries of employees = 47,862,000 Rs per annum = 683,742 $/annum
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VII. Market Prospects
7.1 A brief analysis of demand and supply of the product of the past 5 years and next five years. Global Dimethyl Carbonate Production The key drivers of dimethyl carbonate production are its largest applications in the industries of polycarbonates, paints and coatings. Polycarbonates are currently in very high demand from the rapidly growing end-user industries of automotive and electronics. Both industries are currently in full swing and are expected to continue growing in the near future. As a result, the higher demand for polycarbonates becomes a driver for the manufacture of dimethyl carbonate. Similarly, the paints and coatings industry is being boosted by the construction industry, consequently upping the demand for dimethyl carbonate. With all these factors of influence in place, the global market for dimethyl carbonate is expected to progress at a CAGR (Compound Annual Growth Rate) of 6.6% between 2015 and 2023 in terms of revenue. By the end of 2016, this market revenue should be reaching US$440 mn. By the end of 2023, the market is expected to be valued at US$690.1 mn. In terms of volume, dimethyl carbonate global production is expected to weigh in at 599 kilo tons.
Asia Pacific Demand for Dimethyl Carbonate on the Rise: By the end of 2023, the Asia Pacific demand for dimethyl carbonate is expected to be at 49.26% of the market. Europe comes in at second place in terms of demand, followed by North America in third.
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China is a massive contributor to the Asia Pacific demand for dimethyl carbonate. Together with Japan, the two regions are expected to take up more than three quarters of the total dimethyl carbonate volume in Asia Pacific by 2023. In fact, China is considered to be a top producer and consumer of dimethyl carbonate in the world currently, as the players in this country also export large quantities of dimethyl carbonate to emerging economies. Europe recognized dimethyl carbonate as a non-toxic chemical in 1992, after which it steadily started to replace chloromethane, phosgene, and methyl chloroformate in several end-use industries. A majority of the demand for dimethyl carbonate in Europe is expected to continue originating from Germany and France. Dimethyl Carbonate Market, By Application Global dimethyl carbonate market size for polycarbonate was valued at over USD 200 million in 2015. Polycarbonate is a transparent and strong engineering thermoplastic used in automotive, glazing, electronics, optical media, medical, lighting and appliances markets. Robust growth in the end user industries such as automotive and electronics, along with increasing product usage in these sectors will positively influence industry growth over the forecast timeframe.
Global dimethyl carbonate market share for solvent is projected to expand at over 6% CAGR over the forecast timeframe. The product is an inexpensive oxygenated solvent along with having excellent solubility properties. It can dissolve numerous coating resins. It can also be employed in auto refinish and concrete coatings with its promising solubility, odor, evaporation rate and economic profiles. Furthermore, it can also be used in floor coatings, steel drum linings, traffic paints and architectural coatings owing to boost industry growth.
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U.S Dimethyl Carbonate Market size, by application, 2013-2024 (USD million)
Source: www.gminsights.com
Polycarbonate Industry demand for Dimethyl Carbonate Continues to grow. By 2023, 53.2% of the total volume of dimethyl carbonate produced is expected to be taken up by the polycarbonate industry. Dimethyl carbonate is an important constituent in the manufacture of polycarbonates, as it is used to produce diphenyl carbonate, one of the core chemicals in the condensation polymerization process that produces polycarbonates. The applications of polycarbonates are diverse and include appliances, lighting devices, medical devices, optical media, electronics, and automobiles. Most of these industries, especially the automotive and electronics industries, are showing a positive growth rate. Therefore, their demand for polycarbonates is expected to drive the production of dimethyl carbonate.
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7.2 Present production capacity/licensed capacity in the country giving the status of the production Analysis of Import of dimethyl carbonate By India:
Ref: www.zauba.com
Ref: www.zauba.com
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\
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7.3 Export Potential
Analysis of Export of dimethyl carbonate By India :
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7.4 Marketing set-up and area of consumption
The thriving expansion of some of the key end-use industries of dimethyl carbonate is one of the key factors leading to the steady rise in demand and consumption of this organic compound. Manufacturers are also increasingly preferring dimethyl carbonate as a solvent over other toxic reagents such as phosgene. The usage of dimethyl carbonate in the production of antibiotics, such as ciprofloxacin and carbadox, and pesticides has also witnessed steady expansion in the recent years and these applications continue to remain lucrative for the market.
It is estimated that the global dimethyl carbonate market will massively benefit from the vast surge in uptake of electronics and passenger vehicles, especially across Asia Pacific. The increasing usage of the compound in these products will prove to be highly lucrative for the global dimethyl carbonate market in the longer run. Additionally, the market will likely benefit from the increasing demand from the paints and coatings industry. The thriving construction industry in regions such as the Middle East and Africa and Asia Pacific is expected to drive the regional paints and coatings markets, which will, in turn, propel the growth of this market.
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VIII. Site selection: The flexibility of the plant & site selection is mainly based upon the following: i. Raw materials availability ii. Markets iii. Energy iv. Climate v. Transportation facilities vi. Water supply vii. Waste disposal viii. Labor supply ix. Taxation and legal restrictions x. Site characteristics xi. Flood and fire protections
Based upon all these factors we have chosen Kandla (SEZ), Gujarat as the potential site for the project. Availability of port makes the procurement of raw material by imports quite easy.
Alternatives sites may be Mundra, Ahmedabad and Surat (Gujarat), but due to the availability of SEZ (400 Ha) for chemicals in Kandla and being a PCPIR (Petroleum, Chemicals and Petrochemicals Investment Region), it is the best suited for our project.
Advantages of Gujarat The advantages in selecting Gujarat as the site for the project are described below: 1. Raw material supply: As mentioned above, these all suppliers are suited in Gujarat, near our project site. The availability of raw material makes the selection of Kandla as the project site very obvious. Handling and transportation of the raw materials will be eased due to the lesser distance between the supplier and project site.
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2. Robust Infrastructure: a) Dependable Power supply: This factor is a key to industrial development. Present power generation capacity of Gujarat is 9,628 MW, plans afoot to raise it to 25,000 MW by 2012. Per capita power consumption is 1354 units against national average of 665 units. Also there is rich availability of natural gas (34 MMCD) and lignite (1,072 MMT) in Gujarat. b) Transportation facilities: Total road length in Gujarat is 74,018 Km, whereas rail length is 5,188 Km (8.25 % of India), 13 airports and 42 ports along 1,600 km coastline also make Gujarat a favorite location for industries and businesses. Kandla (itself a large seaport city), situated between Vadodara and Surat, is well connected through roadways, railways and airways. c) Utilities: Kandla has always been prosperous because of its location on the Narmada River. Although water tends to be scarce in Gujarat, one never finds difficulty in getting water in Kandla. Because of this, agriculture and other linked commercial activities have flourished in Kandla.
3. Initiatives by Government: a) Licensing policy: • In Chemical sector, 100% FDI is permissible. • The entrepreneurs need to submit only IEM with the Department of Industrial Policy and Promotion provided no locational angle is applicable. b) Custom duty: • The peak rate of custom duty on most Chemicals is 7.5%. • On basic raw materials like acid grade fluorspar, Sulphur, rock phosphate, natural borates are 5%. • On most building blocks and feedstock, the duty is 5% (ethylene, propylene, crude, naphtha, benzene, xylene, Ethyl benzene) c) Excise duty: • On almost all chemicals the excise duty is 16%.
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4. SEZ Advantages: For SEZ units● Income tax incentives: 10-year corporate tax holiday on export profit, 100% for the initial 5 years and 50% for the next 5 years. ● Other benefits; ○ Exemption of electricity duty—10 years ○ Duty free procurement of capital goods (including second hand capital goods), raw materials and consumable spares from domestic markets. ○ Full freedom for sub-contracting. ○ Facility to realize and repatriate export proceeds within 12 months. ○ Facility to retain 100% foreign exchange receipts in the export earner’s foreign currency account. ● Indirect tax incentives (for both SEZ units & Developers) ○ Nil custom duty. ○ Nil excise duty. ○ Exemption from central sales tax. ○ Exemption from service tax. ○ Exemption from securities transaction tax. ○ Exemption from tax on sale of electricity for self-generated and purchased power. Besides above, Gujarat has very liberal labor policies for SEZ and SEZ Development committee monitors infrastructure development for each SEZ.
5. Global competitiveness: ● The chemical industry in Gujarat is a significant component of the State’s economy, contributing to more than 51% of Indian production of major chemicals with revenues at approximately more than INR US$ 3 billion. Gujarat contributes 15% of the total national chemical exports.
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● Petrochemical Industry in Gujarat produces 13.048 Million Tons of petrochemical products and contributes around 62% to the total production of the country. ● Bulk of the exports from this sector goes to market such as USA, Europe and other developed countries- a clear sign of global competitiveness. ● Gujarat has been the ideal destination for several leading MNCs including BASF, Bayer, DuPont, GE Plastics, Claim Energy, Solvay, Shell, British Gas, Perstrop, Huber, Heubach colours and Cheminova.
6. Market Advantages: While the State Chemicals industry exhibits several similarities to the global chemical industry, there are several characteristics specific to the Gujarat across sub-segments. At the industry level, Gujarat chemical industry is characterized by: ● High domestic demand potential, as the Indian markets develop and per capita consumption level increase. ● High degree of fragmentation and small-scale operations. ● Limited emphasis on exports due to domestic market focus and smaller scale of operation. ● Low cost competitiveness as compared to other countries.
7. Quality Workforce and Educational Infrastructure: Gujarat is also famous for its educational infrastructure and quality workforce. ● Least man days lost due to industrial unrest. ● Large pool of skilled technical personnel available. ● 39 engineering colleges offering diploma courses in chemical engg. ● 49 Polytechnics offering diploma courses in chemical engg. (e.g. K. J. Polytechnic, Kandla ● Location of kandla in Gujarat.
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8.2 Project Layout Plant Layout considerations After selecting a plant site for the plant, plant layout is a crucial factor in the economics and the safety of process plant. Some of the ways, in which plant layout contributes to safety and loss prevention (SLP), & which are included in the layout design are: 1. Economic considerations: construction and operation cost, 2. Segregation of different risks. 3. Minimization of vulnerable pipe work. 4. Containment of accidents. 5. Limitation of exposure. 6. Efficient and safe construction. 7. Efficient and safe operation. 8. Efficient and safe maintenance. 9. Safe control room design. 10. Emergency control facilities. 11. Firefighting facilities. 12. Access for emergency services. 13. Security. 14. Future Expansion. 15. Modular construction.
Our plant layout mainly includes the following buildings and construction as per the process requirements and support activities: 1. Plant Area (including boiler house, pump house, cooling tower, water treatment plant etc.). 2. Power plant. 3. Storage. 4. Repair and Maintenance Workshop. 5. Plant Utilities.
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6. Loading Area (train, tankers, trucks etc.). 7. Stores. 8. R & D Centre. 9. Laboratories. 10. Quality Control Wing. 11. Pollution Control Wing. 12. Fire & Safety Station. 13. Medical Centre. 14. Bank & Post Office. 15. Recreation & Staff Facilities. 16. Administrative Block. 17. Marketing Block. 18. Training Centre. 19. Petrol Pump. 20. Security Wing. 21. Canteen. 22. Parking (Light Vehicles & Heavy Vehicles) 23. Lawns & Fountains. 24. Green Belt Area. 25. Space for Future Expansion. A site layout for the plant is provided on the next page. Considerations have been given for the future expansions. Some area has been marked for Green Belt. Hazardous materials are kept at a safe distance from the offices and other staff facilities.
Description: Location of buildings ● Buildings which are the work base for several people should be located to limit their exposure to hazards. Analytical laboratories should be in a safe area, but otherwise as close as possible to the plants served. So, should workshops and general stores. The main
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office block should always be near the main entrance and other administration buildings should be near this entrance if possible. ● Other buildings such as medical centers, canteens etc. should be in a safe area and the latter should have ready access for food supplies. ● All buildings should be upwind of plants which may give rise to objectionable features. Water drift from cooling towers can restrict visibility and cause corrosion or ice formation on plants or transport routes and towers should be sited to minimize this. ● Another problem is recycling of air from the discharge of one tower to the suction of another, which is countered by placing towers cross-wise to the prevailing wind. The entrainment of effluents from stacks and of corrosive vapors from plants into the cooling towers should be avoided as should the siting of buildings near the tower intakes. ● The positioning of natural draught cooling towers should also consider resonance caused by wind between the towers. The problem of air recirculation should also be borne in mind in siting air-cooled heat exchangers. Economic Considerations ● The cost of construction can be minimized by adopting a layout that gives the shortest run of connecting pipe between equipment and the least amount of structural steel work. However, this will not necessarily be best arrangement for operation and maintenance. ● Some features which have a particularly strong influence on costs are foundations, structures, piping and electrical cabling. This creates the incentive to locate items on the ground to group items so that they can share a foundation or a structure and to keep pipe and cable runs to a minimum. Safety Considerations ● Plants which may leak flammables should generally be built in the open or, if necessary, in a structure with a roof but no walls. If a closed building cannot be avoided, it should have explosion relief panels in the walls or roof with relief venting to a safe area. Open air construction ventilates plants and disperses flammables but as already indicated, scenarios of leakage and dispersion should be investigated for the plant concerned.
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● Fire spread in buildings should be limited by design, as should fire spread on open structures. Sprinklers and other protective systems should be provided as appropriate. Plants which may leak toxics should also generally be built in the open air. The hazardous concentrations for toxics are much lower than those for flammables, however, and it cannot be assumed that an open structure is always sufficiently ventilated. ● Ventilation is necessary for buildings housing plants processing flammables or toxics. Air inlets should be sited so that they do not draw in contaminated air. The relative position of air inlets and outlets should be such that short circuiting does not occur. Exhaust air may need to be treated before discharge by scrubbing or filtering. ● Blast walls may be needed to isolate potentially hazardous equipment and confine the effect of the explosion. At least two escape routes for operators must be provided from each level in the process building. Operations ● Access and operability are important to plant operation. The routine activities performed by the operator should be studied with a view to providing the shortest and most direct routes from the control room to items requiring most frequent attention. ● Equipment that needs to have frequent operator attention should be located convenient to the control room. Valves, sample points and instruments should be located at convenient positions and heights. Sufficient working space and headroom must be provided to allow easy access to equipment. ● Good lighting on the plant is important, particularly on access routes, near hazards and instrument reading. Operations involving manipulation of equipment while observing an indicator should be considered so that the layout permits this. Maintenance ● Maintenance costs are very large in the chemical industry. In some cases, the cost of maintenance exceeds the company’s profit. The engineer must design to reduce these costs. ● Heat exchangers must be sited such that tube bundle can be easily withdrawn for cleaning and tube replacement.
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● Heat exchangers must be sited such that tube bundle can be easily withdrawn for cleaning and tube replacement. ● Vessels that require frequent replacement of catalyst or packing should be located on the outside of the building. ● Equipment that requires dismantling for maintenance such as compressors and large pumps, should be place under cover. Modular Construction ● For convenience of efficient management, the whole plant is assembled section wise at the plant manufacturer’s site in the form of modules. These modules will include the equipment, structural steel, piping and instrumentation. Modules are then transported to the plant site, by road or sea. ● We know that technology is improving day by day. That’s why keeping future expansion in mind, equipment should be located so that it can be conveniently tied in with any future expansion of the process.
Plant Layout
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IX. Economic Evaluation and Profitability of Project
Total Direct Costs:
S.NO
Item
Percent of Purchased Cost
1
Purchased Equipment Cost
100
2,142,200
149,954,000
2
Purchased Equipment Installation
39
835,458
58,482,060
3
Instrumentation and Control
13
278,486
19,494,020
4
Piping
31
664,082
46,485,740
5
Electrical equipment and materials
10
214,220
14,995,400
6
Buildings( Including services)
29
621,238
43,486,660
7
Yard improvements
10
214,220
14,995,400
8
Service Facilities
55
1,178,210
82,474,700
9
Land
6
128,532
8,997,240
5,050,344
353,524,080
Cost in $
Cost in INR
Total direct plant cost (D)
Cost in $
Cost in INR
Indirect Plant Cost: S.N O
Item
Percent of Purchased Cost
1
Engineering and supervision
32
685,504
47,985,280
2
construction Expenses
34
728,348
50,984,360
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3
Contractor's fee
18
385,596
4
Contingency
36
771,192
53,983,440
5
Legal Expenses
4
85,688
5,998,160
2,270,732
158,951,240
Total Indirect Plant cost (I)
26,991,720
Total Capital Investment: S.NO
Description
Cost in $
Cost in INR
1
Total Indirect Cost(I)
2,270,732
158,951,240
2
Fixed Capital investment (FCI), D+I
7,321,076
512,475,324
3
Working Capital (WC), 15% OF FCI
1,098,161
76,871,270
Total capital Investment
10,689,969
748,297,830
Total Product Cost:
Another equally important part is the estimation of costs for operating the plant and selling the products. These costs can be grouped under the general heading of Total Product Cost A tabular form is very useful for estimating total product cost and constitutes a valuable checklist to preclude omissions.
Basis for calculating total product cost is: 1. The Total Product Cost is calculated based on the Annual Cost Basis. 2. Number of days working per year is taken as 320 days. 3. Plant is running in 3-shifts i.e. 24 hrs per day. 4. Capacity of the plant per year is 12000 ton of DMC production.
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Step 3.a. Cost of Raw Materials-
S.No.
Raw Material
Quantity Per Year (ton)
Rate ( per ton), in $
Cost (per year) in $
1
Methanol
16,382.361
800
13,105,888
2
Urea
1,267.200
300
380,100
3
Zinc Oxide
2418
1000
2,418,000
Total raw material cost
10,799,080
Step 3.b. Cost of Power and Utilities S.No
Utility
Consumption
Rate, in $
Cost(per year $)
1
Steam(in ton)
579906
17.14 per ton
9,939,589
2
Power(in kwh)
97270272
50.07 $/ kWh
7,642,660
3
Water(in m3)
18272211.9
0.42 per m3
7,674,329
Total
25,256,578
Step 3.c .Total Annual Direct Production Cost S.n o.
Description
% of DPC
Cost in $
1
Utilities
8.5
477,120
2
Operating labour
0.25
14,032
3
Operating supervision
0.15
8,419
4
Maintenance and repairs
3.3
185,235
5
Operating supplies
3.7
207,687
6
Laboratory charges
0.1
5,613
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Total Annual direct Production Cost
898,106
Step 3.d. Fixed Charges S.NO
Nature of Expenditure
Cost in $
1
Depreciation(11% PEC)
148,049
2
Taxes(5% TDP)
280,659
3
Insurance(1% PEC)
13,459
Total Annual Fixed Charges
442,167
Also, Plant Overhead cost is taken to be 30% of the cost of operating labour, supervision and maintenance. Thus, Plant Overhead Cost = 58,096 INR
Step 3.e.Total Manufacturing Cost (M) S.N o
Description
Total Annual Cost in $
1
Direct Production Cost
5,613,186
2
Fixed Charges
442,167
3
Plant Overhead Cost
58,096
Total Manufacturing Cost(M)
6,055,353
Step 3.f. General Expense S.N o
Nature of Expenses
DEPARTMENT OF CHEMICAL ENGINEERING INDIAN INSTITUTE OF TECHNOLOGY ROORKEE
Cost in $
166
1
Administrative Cost
171,428
2
Distribution & Marketing Cost
420,000
3
Research & Development
520,000
Total GE(G)
1,111,428
Total manufacturing cost (M) = 6,055,353 Total General Expense = 1,111,428 $ Total Product cost=M+G =7,166,781 $
Step 5. Profitability Analysis
Gross profit = Annual revenue through sale - Annual operating cost - salaries of employees = 52,257,142.86 -43,612,226 = 8,644,916 $ Total direct investment = 10,689,969 $ Rate of return = 13.41% Payback period =
Total Fixed Investment Net profit + Depreciation = 1.74 years
Market Value of Finished Product Annual Revenue Through Sales (MC + DMC) Gross Profit Assuming tax percent
DEPARTMENT OF CHEMICAL ENGINEERING INDIAN INSTITUTE OF TECHNOLOGY ROORKEE
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$ per ton
52,257,142.86
$
8,644,916
$
20
%
167
Net Profit
6,915,932
$
Payback Period
1.74
Years
Rate of Return
13.41
%
Step 6. Break Even Analysis For breakeven production annual sales equals the annual cost of production Assuming 100% product demand is there, Annual Direct Production Cost Annual Sales
5,050,344
$
14,400,000
$
Selling Price per Kg
1200
$ per ton
Direct Production Cost (per Kg)
394
$ per ton
Tons production for Break even Point
4208
ton/year
Thus, We find that from 3rd year onwards, cash flow becomes positive which implies that the cost invested is recovered. We had calculated Payback period to be 1.74 years, hence the above results confirm it.
References: ❏ Pichayapan Kongpanna, Varong Pavarajar, Rafiqul Gani , Suttichai Assabumrungrat, “Techno-economic evaluation of different CO2-based processes for dimethyl carbonate production” Chemical Engineering Research and Design 93 (2015) 496–510 ❏ Kartikeya Shukla and Vimal Chandra Srivastava, “Synthesis of organic carbonates from alcoholysis of urea: A review” ISSN: 0161-4940 (Print) 1520-5703 (Online) Journal homepage: http://www.tandfonline.com/loi/lctr20
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❏ Paula Saavalainen, Satish Kabra, Esa Turpeinen, Kati Oravisjärvi, Ganapati D. Yadav, Riitta L. Keiski and Eva Pongrácz, “Sustainability Assessment of Chemical Processes: Evaluation of Three Synthesis Routes of DMC” Hindawi Publishing Corporation, Journal of Chemistry, Volume 2015, Article ID 402315, 12 pages http://dx.doi.org/10.1155/2015/402315 ❏
Dengfeng Wang, Xuelan Zhang, Wei Wei, Yuhan Sun, “Synthesis of Dimethyl Carbonate from Methyl Carbamate and Methanol Using a Fixed-Bed Reactor”, Chemical Engineering Technology.
❏ Coulson & Richardson’s Chemical Engineering Volume 6, Chemical Engineering Design 4th Edition, R. K. SINNOTT ❏ Introduction to Chemical Equipment Design, Mechanical Aspects, B.C Bhattacharya
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