Plant Design.docx

PLANT DESIGN: PRODUCTION OF ETHYLBENZENE

TABLE OF CONTENT

Page 1

2017/2018

PLANT DESIGN: PRODUCTION OF ETHYLBENZENE

2017/2018

EXECUTIVE SUMMARY Styrene who is also known as ethylbenzene, vinybenzene and phenylethene is an organic compound with the chemical formula C6H5CH=CH2. Although styrene was discovered way back in 1839, its commercial production and applications were developed in the 1930s. Post world war period witnessed a boom in styrene demand due to its application in the manufacture of synthetic rubber. This led to a dramatic increase in styrene capacity. Styrene has wide application in producing plastic and synthetic rubber industry. It is mostly used in manufacturing of polystyrene (PS), acrylonitrile-butadiene-styrene (ABS), styrene-acrylonitrile (SAN), styrene-butadiene rubber (SBR) and lattices, unsaturated polyester resins (UP resins) and miscellaneous uses like textile auxiliaries, pigment binders polyester resin, aromatics and intermediate industries. Worldwide, there are commonly five methods of manufacturing of styrene such as catalytic dehydrogenation of ethylbenzene, Oxidation of ethylbenzene to ethyl hyroperoxide , side-chain chlorination of ethlybenzene followed by dechlorination, side-chain of chlorination of ethylbenzne hydrolysis to the corresponding alcohols followed by dehydration and pyrolysis of petroleum recovery. In an effort to find a sustainable method of manufacturing of styrene from ethylbenzene, several design objectives were chosen as a necessity for the proposed system such as identifying suitable catalyst, the economic factor, environmental factor, strategic location to build for styrene plant, the design specifications on the reactors and distillation column used in the plant, the market price and also not to forget the safety issue relating to the plant. Obtaining this data was very crucial before scaling up the design of a complete industrial plant. For the final design of our project, we includes the process flow diagram (PFD) and also Piping and Instrumentation Diagram (P&ID) created by Microsoft Visio, finalized site selection to build the styrene plant, the analysis of reactor and distillation design plus with HAZOP study and FTA analysis in concerning safety relating issue toward the each equipment used in the process background of producing styrene. From this variable aspect, we conclude the proposed plant design would indeed be economically viable and profit inducing.

Page 2

PLANT DESIGN: PRODUCTION OF ETHYLBENZENE

2017/2018

INTRODUCTION Ethylbenzene, is also known as phenyl ethane and Ethylbenzol, C6H5CH2CH3, is an alkyl aromatic compound. This ethylbenzene was mostly used as an intermediate for the manufacture of styrene monomer which is approximately more than 99% of its production, C6H5CH=CH2, one of the most important large-volume chemicals.

Figure 1 Ethylbenzene is used as raw material to manufacture styrene. For making aluminium bromide EB, has been used as solvent in anhydrous electro deposition with aluminium. Less than 1% of the Ethylbenzene produced is used as paint solvent. The reactions that produce Ethyl Benzene and Diethyl Benzene are:

Where, ξ1 is the extent of reaction. The selectivity of these reactions is determined by the feed ratio and processing conditions. Essentially all commercial Ethylbenzene production is consumed for the manufacture of styrene monomer. Styrene is used in the production of polystyrene and a wide variety of other plastics (Styrene). The minor uses, the most significant is in the paint industry as a solvent, which less than 1% of production capacity. Even smaller volumes go toward the production of acetophenone, diethylbenzene, and ethylanthraquinone.

Page 3

PLANT DESIGN: PRODUCTION OF ETHYLBENZENE

2017/2018

PROCESS SELECTION There are several processes to manufacture Ethylbenzene with different catalyst. Some of the process is state below: 1. 2. 3. 4.

Liquid phase aluminium chloride catalyst process Vapour-phase zeolite catalyst process Liquid-phase zeolite catalyst process (EBMAX) Mixed liquid-vapour zeolite catalyst process (CDTECH)

LIQUID PHASE ALUMINIUM CHLORIDE CATALYST PROCESS Alkylation of benzene with in the presence of an aluminium chloride catalyst complex is exothermic. In the conventional AlCl3 process three phases are present in the reactor. Aromatic liquid, ethylene gas, and a liquid catalyst complex. A mixture of catalyst complex, dry benzene, and recycled polyalkylbenzenes is continuously fed to the reactor. Ethylene and the catalyst are injected into the reaction mixture through spargers, and essentially 100% of the ethylene is converted. Due to low ethylene, Benzene ratios are used to give optimum overall yield of Ethylbenzene. As the product ratio is getting increased, more side reactions occur. The loss in net yield due to residue is minimized by recycling this material to the alkylation reactor. The reaction occurs close to thermodynamic equilibrium; therefore traditional processes use a single reactor to alkylatebenzene and transalkylate polyalkylbenzenes. The liquid reactor effluent is cooled and discharged into a settler, where the heavy catalyst phase is decanted from the organic liquid phase and recycled. The organic phase is washed with water and to remove dissolved AlCl3 and promoter. The aqueous phase from these treatment steps in first neutralized and then recovered as a saturated aluminium chloride solution and wet aluminium hydroxide sludge. The unreacted benzene is recovered by the first columns as an overhead distillate. The second column separates the ethylbenzene product from the heavier polyalkylated components. The bottoms product of the second column is fed to a final column, where the recyclable polyalkylbenzenes are stripped from non-recyclable high molecular mass residue compounds. VAPOR-PHASE ZEOLITE CATALYST PROCESS The reactor typically operates at 400-4500C and 2-3 MPa (20-30 bars). At this temperature less than 99% of the net process heat input and exothermic heat of reaction can be recovered as steam. The high-activity catalyst allows transalkylation and alkylation to occur simultaneously in a single reactor. The coke will form as the catalyst will slowly deactivated and requires periodic regeneration; two reactors are included to allow uninterrupted production: one is on stream while the other is regenerated. Regeneration takes 36 hours and is necessary after 6-8weeks of operation. The reactor effluent passes to the purification section as a hot vapour. This steam is used as the heat source for the first distillation column, which recovers the bulk of the unreacted benzene

Page 4

PLANT DESIGN: PRODUCTION OF ETHYLBENZENE

2017/2018

for recycle to the reactor. The remaining benzene is recovered from a second distillation column. The Ethylbenzene product is taken as the overhead product from the third column. The bottoms product from this column is sent to the last column, where the recyclable alkylbenzenes and polyalkylbenzenes are separated from heavy no recyclable residue. LIQUID-PHASE ZEOLITE CATALYST PROCESS: For this process, the alkylation reactor is maintained in liquid phase and uses multiple bed catalyst beds ethylene injection. The ethylene conversion is essentially 100% in the alkylation reactors. The exothermic heat of reaction is recovered and used to produce steams or as heat duty in the distillation columns. More recently, the transalkylation reactor has been designed as liquid phase because of its improved energy efficiency. The transalkylation reaction is conducted in the liquid phase using Mobil TRANS-4 catalyst. The alkylation and transalkylation reactor effluent stream are sent to the distillation sections which consist of primarily of three distillation columns. The first column is a benzene column and it separates unconverted benzene into the overhead stream for recycle to the reactors. The benzene column bottom stream feeds the EB column. The EB column recovers the EB product in the overhead stream and the bottom stream of the EB column feeds the PEB column where PEB is fractionated overhead and recycle to the transalkylation reactor. The bottom stream of the PEB column is removed as the residue stream. MIXED LIQUID-VAPOR PHASE ZEOLITE CATALYST PROCESS: The other name for this process is CDTECH. The design of the plant flow diagram with liquid phase technology is quite same, except the design of the alkylator in the CDTECH is consist of two main sections which is catalytic distillation section and standard distillation section meanwhile in liquid phase technology only run alkylation process in alkylator. The process starts from benzene as feed enter at the top of alkylation reactor and ethylene is fed as vapor below the catalytic distillation section which will produce a counter current flow. Once the alkylator process runs they will achieve stable or equilibrium vapor liquid in vapor phase. Ethylene will dissolve into the liquid phase and activate the catalyst site to alkylate benzene and ethylene to produce the Ethylbenzene. The rapid reaction of ethylene dissolves in liquid phase produce a driving force for additional ethylene to dissolve in active site. In the alkylator the process is in exothermic heat of reaction which will creates vaporisation that can affect the distillation alkylation reaction product, Ethylbenzene, Diethylbenzene and other by product. Then the product will remove from the catalytic distillation columns occur at the bottom stream and containing mainly EB, PEB and other by product.

Page 5

PLANT DESIGN: PRODUCTION OF ETHYLBENZENE

2017/2018

PROCESS BACKGROUND The “Mixed Liquid-Vapour Phase Zeolite Catalyst “process is selected for the manufacture of Ethylbenzene on following considerations: 1. Able to achieve the highest purity of Ethylbenzene which is more than 99% compare to other manufacturing process. 2. The raw material benzene and ethylene needed is lesser. 3. The operating condition is low. 4. Cost of production is lower than other process. 5. Can use from waste benzene and ethylene, which is not pure benzene and ethylene. The raw materials needed to run this MIXED VAPOR-LIQUID PHASE ZEOLITE CATALYST process are as below: 1. Ethylene 2. Benzene 1. Ethylene: Ethylene is manufactured by following processes: 1. Pyrolysis of hydrocarbons (paraffins, preferably ethane). 2. Pyrolysis of naphtha & liquid feed stock 3. Ethanol dehydration 4. from coal 2. Benzene: Benzene is manufactured by following processes: 1. from coal 2. Form petroleum 3. Hydrodealkylation 4. Disproportionation The process can be conveniently split into 3 major sections 1. Alkylation section 2. Transalkylation section 3. Stripping and rectification section Alkylation Reactions: There are two sections in alkylator which is standard distillation and catalytic distillation column, then benzene will feed into the reactor at top while ethylene will feed as vapour at the bottom, in section catalytic distillation will create a counter current flow. After the ethylene dissolves into the liquid phase and rapid the heat of reaction will affect the distillation thus producing main product Ethylbenzene, diethylbenzene and other product. Standard distillation section occurs at the bottom and produce EB, PEB and by product.

Page 6

PLANT DESIGN: PRODUCTION OF ETHYLBENZENE

2017/2018

Transalkylation Reaction: In transalkylation, the excess benzene will react again with ethylbenzene and produce 2 mol of ethylbenzene. This process will occur in fixed beds of the catalyst using liquid-vapour mixture of benzene. This process will occur at temperature range from 220-2500C. Stripping and Rectification: In this reaction the PEB and EB will be fed into this stripping section process with temperature range from 295-3250C depend on the pressure. The heater will provide thermal duty which will increase the alkylation rate of reaction and lower the usage of catalyst. Stripping input will decrease the alkylation temperature needed to run the process.

Page 7

PLANT DESIGN: PRODUCTION OF ETHYLBENZENE

2017/2018

SITE SELECTION We do the Site selection process is to find a suitable place to build up our ethylbenzene production site. Site selection include in evaluating the potential or criteria of a land that has potential to accelerate the business progress. It is important to measure some criteria of a land to make it easy to do the marketing and monopoly the production area. As we know the production of ethylbenzene in Johor is IDEMITSU SM (M) SDN BHD which is located in Pasir Gudang, thus we need to find a better place by evaluating every factor in order to compete with other company. Based on the market survey and preliminary feasibility study, there are few places have been considered for the site selection. Two sites within Peninsular Malaysia were selected for further consideration: Pasir Gudang and Kerteh. The basic aim of site selection is to choose a location that maximizes income and minimizes cost compromises usually have to be made. No site is ever perfect, and it is our mission to discuss the alternatives and compromises on the best choice. No. 1. 2. 3. 4. 5. 6. 7. 8.

Factors

Site Selection Pasir Gudang Kerteh Raw materials availability 5 3 Transportation facilities 5 3 Energy availability 4 4 Water supply 3 4 Waste disposal 5 5 Markets 5 3 Taxation & legal restrictions 3 3 Community factor 4 4 Total 34 29 1 = very bad 2 = bad 3 = Moderate 4 = Good 5 = Very good

Page 8

PLANT DESIGN: PRODUCTION OF ETHYLBENZENE

2017/2018

1. Raw materials availability To produce ethylbenzene, the raw material is ethylene and benzene. We can conclude why we choose industrial park area in Pasir Gudang is because we have a lot of raw material sources come from Pasir Gudang which is LOTTE CHEMICAL TITAN (M) SDN BHD, one of the biggest ethylene and benzene production in Johor, hence easy for our industry to get raw and also save cost for the transportation factor. Here is the estimation for our raw material consume per day:  

For ethylene : range from 9000kmol - 11000kmol per day For benzene : range from 34000kmol - 40000kmol per day Raw materials Benzene

Ethylene

Company Aromatics (M) Sdn. Bhd. Kerteh, Terengganu. 188 000 tonnes per year. Titan Petchem (M) Sdn. Bhd. Pasir Gudang, Johor. 587 000 tonnes per year. Ethylene (M) Sdn. Bhd. Kerteh, Terengganu. 400 000 tonnes per year. Titan Petchem (M) Sdn. Bhd. Pasir Gudang, Johor. 630 000 tonnes per year.

2. Transportation facilities Excellent accessibility from all directions due to its strategic location via Pasir Gudang Highway, Senai-Desaru Highway and JB East Coast. Here are also listed the distance from facilities: State Pasir Gudang, Johor

Kerteh, Terengganu

Page 9

       

Transportation facilities 8 min to Johor Port 15 min to Senai-Desaru Highway 15 min to Coastal Highway 15 min to Tanjung Langsat Port 20 min to Pasir Gudang Highway 33 min to JB Central Business District 43 min to Senai International Airport 57 min to Tanjung Pelepas Port

 

Kerteh Port Kuantan Port

PLANT DESIGN: PRODUCTION OF ETHYLBENZENE

2017/2018

3. Energy availability This factor is depending in our company as industrial site that usually consume a lot of energy usage. We found that Pasir Gudang industrial park is near with power station which is YTL Power International Bhd and make this area labelled as high energy availability. Below shows the pricing and tariff for electric energy monthly: TARIFF E1 - MEDIUM VOLTAGE GENERAL INDUSTRIAL TARIFF For each kilowatt of maximum demand per month For all kWh The minimum monthly charge is

29.60 RM/kW 33.70 sen/kWh RM600.00

TARIFF E2 - MEDIUM VOLTAGE PEAK/OFF-PEAK INDUSTRIAL TARIFF For each kilowatt of maximum demand per month during the peak period For all kWh during the peak period For all kWh during the off-peak period The minimum monthly charge is

37.00 RM/kW 35.50 sen/kWh 21.90 sen/kWh RM600.00

4. Water supply Our plant is non-domestic user. We get our water supply from SAJ which is the main water supply in Johor. The table below was the standard water calculation that being used by the consumer in this district.

Page 10

PLANT DESIGN: PRODUCTION OF ETHYLBENZENE

2017/2018

5. Waste disposal All industrial processes produce waste products, and full consideration must be given to the difficulties and cost of their disposal. The disposal of toxic and harmful effluents will be covered by local regulations, and the appropriate authorities must be consulted during the initial site survey to determine he standards that must be met. An environmental impact assessment should be made for each new project or major modification or addition or an existing process. The site-product or by-product of ethyl benzene production is polyethylbenzene (PEB) where we will not dispose it because it has other use. PEB can be used as fuel in an integrated styrene, which means we can sell it to company that produce styrene like IDEMITSU SM (M) SDN BHD. So instead of we dispose it, we can make additional income into our company. 6. Markets Our plant is located at Pasir Gudang Industrial Park which is one of the hotspot areas of chemical and material production. Near to the Johor Port and Tanjung Langsat Port also give huge advantages for our plant as it is world - class container port where consumer can get supply from our production. It is also take less than an hour to get to airport for deliver consumer’s order through flight. Besides, we can get customer that need our product at the area Pasir Gudang for example, like IDEMITSU SM (M) SDN BHD, running production of styrene from ethylbenzene. 7. Taxation & legal restriction Capital grants, tax concessions, and other inducements are often given by governments to direct new investment to preferred locations such as areas of high unemployment. The overriding of such grants can be the overriding considerations in site selection. A corporate tax rate of 25% applies to both local and foreign-owned companies in Malaysia. Besides that, Pasir Gudang - Tanjung Langsat area (Eastern Gate Development Johor) is a freetradezone (FTZ). 8. Community factor The proposed plant must be fit in with and be acceptable to the local community. Full consideration must be given to the safe location of the plant so that it does not impose a significant additional risk to the community. On a new site, the local community must be able to provide adequate facilities for the plant personnel: schools, banks, housing, and recreational and cultural facilities. In order to do research and development for our company, there are a few universities which are located at Pasir Gudang that help us. This can be our supporting medium as we will do cooperation with all these near university. For development of employee, Johor Corp will help us in producing good employee as it operates its own development centre. So this will ease our company to hire employee to manage our plant.

Page 11

PLANT DESIGN: PRODUCTION OF ETHYLBENZENE

2017/2018

PLANT LOCATION

FIGURE 1.0 FUTURE SITE LOCATION

The figure above is our future site location (in the red circle area) is located at Jalan Suasa, Kawasan Perindustrian Pasir Gudang, 81700 Pasir Gudang, Johor, Malaysia. This site location is located next to Johor Port which the area occupies 8 acres and it is only 6km far (12min) from LOTTE CHEMICAL TITAN (M) SDN BHD where our company get the raw material which are ethylene and benzene. In addition, the site selection already has storage of machinery, container, truck, pilling machine and tower crane.

Figure (A)

Page 12

PLANT DESIGN: PRODUCTION OF ETHYLBENZENE

2017/2018

Figure (B)

PLANT LAYOUT Plant layout involves developing physical equipment for a processing facility. The development must affect a balance of equipment spacing and integration of specific systems related to facility. Various configurations are formed based on the main part of the process unit which is the pipe rack, which contains long process and the utility lines that connect distant equipment and product piping entering and leaving the plant. Space for instrument and electrical feeders is allocated in the pipe rack such that they are connected to the related equipment. This area is kept free of piping and its related supports. In developing the plant layout for our Ethylbenzene plant, it is essential that the firm decisions are made early as to equipment arrangement. This eliminates changes, which cost man-hours as the job progresses through engineering and design. The distillation sections are based on a grade-level process plant lay out configuration. The steam generation and power facilities are housed in a building. The basic arrangement follows the equipment spacing charts.

Page 13

PLANT DESIGN: PRODUCTION OF ETHYLBENZENE

Page 14

2017/2018

PLANT DESIGN: PRODUCTION OF ETHYLBENZENE

Page 15

2017/2018

PLANT DESIGN: PRODUCTION OF ETHYLBENZENE

2017/2018

HAZARD AND RISK ASSESSMENT HEALTH AND SAFETY aspects of the personnel & equipment are important in the plant. The plant has a variety of compounds that are hazardous to personnel as well as environment. Fire accidents, exposure to chemicals and explosions are some of the major hazards in the operation the plant. Hence safety and environment are given a careful attention. Item

Study note

Process Parameters

Deviation

R-100

Alkylation Reactor

Flow rate

No

Possible Causes i.

ii.

High

i. ii.

Less

i.

ii.

Temperature

High

i. ii. iii.

Page 16

blockage in the pipeline at stream 1 & 2 failure of the pump/compress or feed

Possible Consequences i. ii.

level indicator malfunction valve loose and cannot be closed tightly

i. ii.

leakage from the pipeline at stream 1 & 2 slow pump pressure uses in feed

i.

thermocouple failure in reactor temperature control failure cooling system does not function

ii.

i. ii.

Action Required

No reaction inside the reactor potential to cause high pressure in the pipeline if there is blockage

i. ii.

frequently check the pump install the flow indicator in pipeline

overflow of feed potential to over pressurize the reactor because too much flow of gas ethylene

i.

put high level flow alarm or meter flow sensor add on extra valve to the pipeline provide emergency transfer shutdown capability on reactor do pump/compressor maintenances before undergo the process install low pressure sensor alarm to alert the operator

the reaction cannot get high conversion to Ethylbenzene cannot achieve the targeted production per day as low flow from feed for process could damage reactor the mixture cannot undergo right temperature thus fail the reaction

ii. iii.

i.

ii.

i. ii.

install high temperature (TAH) inspection the cooling system

PLANT DESIGN: PRODUCTION OF ETHYLBENZENE

Low

i.

ii. Pressure

High

i.

ii.

Low

i.

ii.

T-100 / T-101 / T-102 / T-103

Distillation Columns

Flow rate

No

i.

ii.

heating system/element do not run properly too much coolant uses in reactor compressor control in stream feed malfunction the operator misleads the process by setting over pressure leakage at stream 1 or stream 2 valve fail to operate blockage in the pipeline at column stream pump do not function or closed

2017/2018

i.

ii. i.

ii. iii.

i. ii.

i.

ii.

iii.

High

i. ii. iii.

Page 17

valve cannot close the flow pressure too high from pump failure of pressure gauge

i.

ii.

the rate of reaction gets slower as the temperature is lower than required production of Ethylbenzene is less damage the reactor as the overpressure occur burst the reactor production yield not at optimum quality

reaction rate slowdown the flow of feed hard to maintain and manage to undergo reaction cannot separate the mixture in output stream no production for distillation column since pump cannot push the flow diethylbenzene recycle cannot be complete overpressure in column and might damage the tank and cause leakage the column cannot operate at optimum

i. ii. iii.

i. ii. iii.

i. ii. iii. i.

ii.

i. ii. iii.

install the temperature alarm (TAL) install flow regulator design larger pipe system

trigger emergency automatic shutdown put high pressure alarm install pressure relief to eliminate the over pressure

operator need to check all valve before processing maintain the functioned of pipeline install bypass pipeline for replacement add bypass pipeline with manual if there is any blockage valve in other pipeline make sure to check and maintain the good condition of valve

put high flow water sensor setting the pump with correct pressure and do inspection design valve pressure relief with extra size to control situation over pressure

PLANT DESIGN: PRODUCTION OF ETHYLBENZENE

2017/2018

to indicate pressure use iii.

Less

i.

ii.

iii. R-102

Finishing Feactor

Temperature

High

i. ii.

Low

i. ii. iii.

Pressure

High

i. ii.

Low

i. ii.

Page 18

leakage happen inside the pipeline at product stream less pressure from the centrifugal pump pump malfunction cooling system do not function thermocouple

thermocouple failure heater malfunction electric device failure pressure gauge failure operator wrong setting process specification leakage at the pipeline compressor fail to function

i.

ii.

iii.

i. ii.

i. ii.

i.

ii. i.

condition & effect the process the tank fill faster than the setting and create situation valve cannot be closed the rate of reaction and production will be slower the process cannot complete as the flow less wasting product from leakage accident and loss of time cannot operate under optimum condition the product from reactor disturbed

more cooling flow off specification product

overpressure and cause bursting in reactor costing to repair the damage part not meet right optimum pressure

i. ii.

install low flow meter alarm equip more pump as extra

i.

install high temperature sensor (TAH) install emergency shutdown in case high temperature that will costly to repair damage add low temperature sensor (TAL) back-up power such as supply generation

ii.

i. ii.

i. ii.

i. ii.

put pressure relief valve at reactor install high pressure sensor alarm maintain the function of pipeline do inspection at the

PLANT DESIGN: PRODUCTION OF ETHYLBENZENE

R-101

Transalkylator

Flow rate

Pressure

2017/2018

i.

valve not functioning well

i.

The flow overspill

i.

Low

i.

i.

Decreasing efficiency of reaction

i.

Check the flow rate regularly and manually

High

i.

i.

The reactor rupture

will

i.

Install high pressure sensor alarm

Low

i.

Level indicator not working properly Pressure controller malfunction Pressure controller malfunctioning

i.

Can cause different percentage of product high activation energy use Causing explosion

i.

Doing inspection regularly

i. ii.

Check temperature regularly install high temperature sensor

ii. Temperature

compressor Do the inspection on the equipment regularly

High

High

Page 19

i.

Thermocouple failed to function well

i.

PLANT DESIGN: PRODUCTION OF ETHYLBENZENE

2017/2018

PLANT DESIGN: PRODUCTION OF ETHYLBENZENE

2017/2018

PLANT DESIGN: PRODUCTION OF ETHYLBENZENE

2017/2018

PLANT DESIGN: PRODUCTION OF ETHYLBENZENE

2017/2018

PLANT DESIGN: PRODUCTION OF ETHYLBENZENE

2017/2018

Block flow diagram (BFD) for ethylbenzene production

PLANT DESIGN: PRODUCTION OF ETHYLBENZENE 2017/2018

Process flow diagram (PFD) for ethylbenzene production

PLANT DESIGN: PRODUCTION OF ETHYLBENZENE 2017/2018

Piping and Instrumentation (P& ID) for ethylbenzene production

PLANT DESIGN: PRODUCTION OF ETHYLBENZENE 2017/2018

PLANT DESIGN: PRODUCTION OF ETHYLBENZENE

Process equipment symbols and numbering Table : Process equipment symbols and numbering Numbering

Process Equipment

2017/2018

PLANT DESIGN: PRODUCTION OF ETHYLBENZENE

MATERIAL BALANCE FOR THE PRODUCTION OF ETHYLBENZENE

2017/2018

PLANT DESIGN: PRODUCTION OF ETHYLBENZENE

2017/2018

ENERGY BALANCES FOR THE ETHYLBENZENE ENERGY BALANCE CALCULATIONS 1. Mass Balance

In the process design, mass balance and energy balances are made to determine the energy requirements of the process: the heating, cooling and power required in the plant operation. It is important to determine the composition for condenser and reboiler streams. At the enriching section, the composition for the first distillate product is similar after entering the condenser. The purpose of the condenser is to remove the amount of heat to convert the mixture into liquid. The flowrate of recycle stream from condenser output will be calculated by using reflux ratio that have been calculated that is L/D=1.5. From the figure above, the distillate flowrate is 1271.836 kg/hr. So, we can calculate the n2 flowrate by using:

PLANT DESIGN: PRODUCTION OF ETHYLBENZENE

2017/2018

𝐿 = 1.5 𝐷 𝐿 𝑘𝑔 1271.8362 ℎ𝑟

= 1.5

L = 1.5(1271.8362 kg/hr) L=1907.7543 kg/hr

Since the flowrate value of L had been calculated. Hence, the m2 is 1907.7543 kg/hr and the value of m1 can be calculate by:

m1 = m2 + D m1 = 1907.7543 kg/hr + 1271.836 kg/hr m1 = 3179.5905 kg/hr For stripping section, the value of n4 has to be calculated by using a mccabe-thiele graph. The amount Lm/Vm+1 is calculated by finding the gradient of SSOL line from the past sizing assignment calculations. The value of gradient is calculated by:

Lm Vm+1

= 1.3

Vm+1 = Lm – B

𝐿𝑚 = 1.3 𝐿𝑚 − 𝐵

Lm = 13 (598.5108) = 7780.6404 kg/hr

Then, the flowrate value for Vm+1 that is output recycle stream from reboiler is calculated by using the equation input=output.

PLANT DESIGN: PRODUCTION OF ETHYLBENZENE

2017/2018

Vm+1 = Lm – B Vm+1 = 7780.6404 kg/hr – 598.5108 kg/hr Vm+1 = 7182.1296 kg/hr

Specific heat capacity For production of ethylbenzene process, the heat capacity for ethylbenzene and diethylbenzene need to be calculate by using kopps rule (table B-10): Cp ( heat capacity for ethylbenzene) = C8H10 = (8 x 12) + (18 x 10) = 276 J/kg.℃ Cp (heat capacity for diethylbenzene) = C10H14 = (10 x 12) + (18 x 14) =372 J/kg.℃

Boiling Point  

The boiling point for ethylbenzene is 136 ℃. The boiling point for diethylbenzene is 187℃.

ENTHALPHY TABLE

Condenser Ref, EB (V,140℃, 1 atm), DEB ( V, 140℃, 1 atm) Input Substance Ethylbenzene (L) Diethylbenzene (L) Ethylbenzene(v) Diethylbenzene (v) Ethylbenzene (L) Dieethylbenzene (v)

M 3109.63 69.95 -

output H 0 H5 -

M 1243.855 27.98 1865.783 41.971

H H1 H2 H3 H4

PLANT DESIGN: PRODUCTION OF ETHYLBENZENE

Hypothetical Path 

H1 = H3 140 ℃, 1 atm)

EB (V, ΔH = ∫ Cp dT = -1.104 KJ/mol

136 ℃, 1 atm)

EB (V, Hv = 35.98 KJ/mol

EB (L,

136℃, 1 atm) ΔH = ∫ Cp dT = -30.64KJ/mol

EB (L, 25℃ , 1 atm)

H(total) = -1.104 + 35.98 + (-30.64 ) = 4.236 KJ/mol 

H2 = H4 (V, 200 ℃, 1 atm)

DEB ΔH = ∫ Cp dT = -4.836 KJ/mol

DEB

(V, 187℃, 1 atm ) Hv = 0.109(bp) = 20.383 kJ/mol

DEB (L,

187℃, 1 atm) ΔH = ∫ Cp dT = - 60.264KJ/mol

DEB (L, 25℃ , 1 atm) Total H= -44.717

2017/2018

PLANT DESIGN: PRODUCTION OF ETHYLBENZENE



2017/2018

H5

DEB (V,

200℃, 1 atm) ΔH = ∫ Cp dT = - 60.264KJ/mol

DEB (V, 145℃ , 1 atm) Input Substance Ethylbenzene (L) Diethylbenzene (L) Ethylbenzene(v) Diethylbenzene (v) Ethylbenzene (L) Dieethylbenzene (v)

m 3109.63 69.95 -

H 0 -60.264 -

output m H 1243.855 4.236 27.98 -44.717 1865.783 4.236 41.971 -44.717

Total H input 0 43.39 -

Total H output 46.47 -6.44 185.88 -25.94

Q= H(output)- H(input) = (46.47 +(-6.44) + 185.88 +(-25.94))- 43.39 = 156.58 kJ/mol

Reboiler Ref, EB (L,25℃, 1 atm), DEB ( L, 25℃, 1 atm)

Substance Ethylbenzene (L) Diethylbenzene (L) Ethylbenzene (v) Diethylbenzene (v) Ethylbenzene (L) Diethylbenzene (L)

Input m 848.0898 6932.55 -

output H 0 0 -

m 782.8521 6399.27 65.2377 533.2731

H H6 H7 0 0

PLANT DESIGN: PRODUCTION OF ETHYLBENZENE

Hypothetical Path 

H6 120 ℃, 1 atm)

EB (L, ΔH = ∫ Cp dT = 4.416KJ/mol

136 ℃, 1 atm)

EB (L, HV = 35.98

EB (V,

136℃, 1 atm) ΔH = ∫ Cp dT = 1.104 kJ/mol

EB (V, 140℃ , 1 atm)

H(total) = 4.416 + 35.98 + 1.104 = 41.5 kJ/mol 

H7 120 ℃, 1 atm)

EB (L, ΔH = ∫ Cp dT = 24.924 kJ/mol

187 ℃, 1 atm)

EB (L, HV = 0.109(BP) = 20.383 kJ/mol

EB (V,

187℃, 1 atm) ΔH = ∫ Cp dT = -17.484 kJ/mol

EB (V, 140℃ , 1 atm) H(total) = 24.924 + 20.383 + (-17.484) = 27.823 kJ/mol

2017/2018

PLANT DESIGN: PRODUCTION OF ETHYLBENZENE

Substance Ethylbenzene (L) Diethylbenzene (L) Ethylbenzene (v) Diethylbenzene (v) Ethylbenzene (L) Diethylbenzene (L)

Input m 1.24 52.82 -

Q= H(output)- H(input) = (46.895 + 4336.06) - 0 = 1382.96 kJ/mol

output H 0 0 -

m 1.13 48.02 0.113 4.802

H 41.5 27.823 0 0

Total H input -

2017/2018

Total H output 46.895 1336.06 -

PLANT DESIGN: PRODUCTION OF ETHYLBENZENE

2017/2018

SIZING FOR PRIMARY DISTILLATION COLUMN (MULTI-COMPONENT DISTILLATION)

SIZING CACULATION FOR EB DISTILLATION COLUMN ṁ2 = 1271.8362

ṁ1 = 1870.347

𝐾𝑔 ℎ𝑟

EB: x1 = 0.978 ,n1 = 1243.781

𝐾𝑔 ℎ𝑟

DEB: x2 = 0.022, n2 = 28.0552

𝐾𝑔 ℎ𝑟

𝐾𝑔 ℎ𝑟

EB Column EB: z1 = 0.7 , n1 = 1309.243

𝐾𝑔 ℎ𝑟

DEB: z2 = 0.3 , n2 = 561.104

𝐾𝑔 ℎ𝑟

95% conversion of distillate

ṁ3 = 598.5108

𝐾𝑔 ℎ𝑟

EB: x1 = 0.109, n1 = 65.462

𝐾𝑔 ℎ𝑟

DEB: x2 = 0.891, n2 = 533.0488

𝐾𝑔 ℎ𝑟

Figure 4.1 Ethylbezene Mass Balance In design of distillation column, first we calculate the no. of stages required for desired separation of component of feed mixture. In our process, we want to separate benzene from ethylbenzene & diEthylbenzene. We get 100.0% benzene as overhead product & 0.0% as bottom product. (ASSUMPTION) Total feed =1,870.347 Kmol product XD= 0 .95 , XB= 0.05 , XF= 0.90 Assume our system is ideal system Therefore→α=P0A/ P0B Where P0A= Vapour pressure of A at 463K P0B= Vapour Pressure of B at 463 K α= 3.44

PLANT DESIGN: PRODUCTION OF ETHYLBENZENE

2017/2018

𝛼𝑥

Plot equilibrium curve using x and y data, use 𝑦 = 1+(𝛼−1)𝑥 x y

0.0 0.0

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 0.276 0.462 0.595 0.696 0.774 0.837 0.889 0.932 0.968 FIGURE 4.2 Vapour-Liquid Equilibrium Data For Ethylbenzene System Assume all the feed is in liquid, q= 1

1.0 1.0

From graph, x’= 0.7 and y’= 0.889 𝐿 𝐷

= 1.5 (Assumption) 𝑅𝑀 𝑋 −𝑦′ = 𝑦𝐷′ −𝑥′ ) 𝑅 0.95−0.889 𝑅𝑀 = 0.889−0.7

Minimum reflux ratio, RM (

= 0.3228 Operating reflux ratio, R = 0.3228(1.5) = 0.484 Operating line of rectification section: It is pass from (0.95, 0.95) on the diagonal & intercept on Y-axis =

𝑋𝐷 𝑅+1

=

0.95 (0.484+1)

= 0.64 Operating line of striping section: It is pass from (0.05, 0.05) on the diagonal & the point of intersection of feed line & operating line of rectification section (0.7, 0.889) No. of theoretical plates including reboiler = 8.9 (From Graph) No. of theoretical plates required in the column = 10 or >10 Assume overall efficiency of trays = 60% Therefore actual no. of plates =

𝑡ℎ𝑒𝑜𝑟𝑖𝑡𝑖𝑐𝑎𝑙 𝑛𝑜.𝑜𝑓 𝑠𝑡𝑎𝑔𝑒𝑠 (𝑒𝑓𝑓𝑖𝑐𝑖𝑒𝑛𝑐𝑦 𝑜𝑓 𝑡𝑟𝑎𝑦/100)

= 14.8 @ 15 trays

=

8.9 0.60

PLANT DESIGN: PRODUCTION OF ETHYLBENZENE

2017/2018

PLANT DESIGN: PRODUCTION OF ETHYLBENZENE

2017/2018

Figure 4.3 The Equilibrium Data Graph For Ethylbenzene System Properties of EB at 1bar k= 0.107 m/s density in vapour= 2.5 X 10-5 kg/m3 density in liquid= 866 kg/m3 Vw = 0.3455 kg/s 𝜌𝐿 − 𝜌𝑉 𝜌𝑉

𝑉 = (𝑘)√

866−2.5𝑥10−5 2.5𝑥10−5

= (0.107)√

= 629.575 m/s 𝑃𝑉 = 𝑛𝑅𝑇 (13.6092)(1.00L) = n(0.08206)(273K+190) n = 0.3582 mol x 106.17 g/mol m = 38.03 g new 𝜌𝑉 = 38.03 g/1 L x 1 L/1000 m3 x 1 kg/1000 g = 3.803x10-5 Diameter of distillation column, Dc

4(𝑉𝑤 ) 𝜋(𝜌𝑣 )(𝑉) 4 𝑥 0.3455 =√ 𝜋(3.803𝑥10−5 )(629.575) = 4.3 meters 𝐷𝑐 = √

Total height of the distillation column = overhead area section + (tray spacing x no. of stages) + (tray deck thickness x no. of stages) + liquid holdup section = 1.5m + (0.6m x 15) + (0.0025m x 15) + 4m h = 14.5375 meter

PLANT DESIGN: PRODUCTION OF ETHYLBENZENE

CONCLUSION OVERHEAD AREA (1.5 meter) -At top 5 to 10 ft add needed to allow for disengaging space.

TRAY SECTION (15 stages) Tray spacing (0.6 meter) -provide better economic trade-off between height of column and diameter of column. Tray deck thickness (0.0025 meter) -easy for worker to assembles and detach for maintenance purpose; the thicker the tray, the higher the cost.

LIQUID HOLDUP SECTION (4 meter) -Liquid holdup section must be tall enough to serve as a liquid reservoir (5 minutes keep) holdup -so that total material entering base can be contained at least 5 minutes before reaching the bottom tray.

Figure 4.4 Sketch of The Designed Distillation Column

2017/2018

PLANT DESIGN: PRODUCTION OF ETHYLBENZENE

2017/2018

CONCLUSION Nearly all commercial ethylbenzene is produced by alkylation of benzene with ethylene. Earlier processes were based on liquid phase alkylation using an aluminium chloride catalyst but this route required disposal of aluminium chloride waste. We as a team agree that Pasir Gudang , Johor is the most suitable location for our plant. Since the raw material supply is near to our targeted area and the ethylbenzene is highly demand intermediate product ,we could get higher profit. Transportation and the commodity nearby also plays the main roles in choosing Pasir Gudang to be the place for our plant build. Last but not least, the construction of the plant could increase the job opportunities for the and lead to the good economies.