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Document Title:
Final Report ENERGY MANAGEMENT ASSESSMENT / AUDIT FOR PSC CORRIDOR (SUBAN-GRISSIK-RAWA)
COPI Doc No.:
Originator: COPI Group Owner: Area: Location: System: Document Type: Discipline / Sub discipline: Old COPI Document No.:
COPI UO – Engineering – Onshore Sumatra General General General System Final Report -
1
IFR
14 Dec 07
Issued for Review
2
IFR
14 Jan 08
Issued for Review
Rev
Status
Issue Date
Reason for Issue
Prepared
Checked
Approvals
Printed initials in the approval boxes confirm that the document has been signed. The originals are held within Document Management.
Final Report
ID-N-GN-00000-00000-00068
Energy Management Audit / Assessment for PSC Corridor ConocoPhillips Indonesia
Revision Sheet
Page 2 of 109
PT.E M I (Persero)
ConocoPhillips Indonesia Inc. Ltd
REVISION
DATE
DESCRIPTION OF CHANGE
1
14 Dec 07
Issued for Review
2
14 Jan 08
Issued for Review
Final Report
ID-N-GN-00000-00000-00068
Energy Management Audit / Assessment for PSC Corridor ConocoPhillips Indonesia
Page 3 of 109
CONTENTS I. INTRODUCTION II. METHODOLOGY 2.1
METHODOLOGY OF ENERGY ASSESSMENT
2.2
METHODOLOGY OF CALCULATION 2.2.1 CALCULATION OF EQUIPMENT 2.2.2 CALCULATION OF SYSTEM
III. ENERGY ASSESSMENT AT SUBAN GAS PLANT 3.1. GENERAL PLANT OPERATION AND PERFORMANCE 3.3.1. GENERAL PLANT OPERATION OF SUBAN GAS PLANT 3.3.2. GENERAL PLANT PERFORMANCE OF SUBAN GAS PLANT 3.2. PERFORMANCE EVALUATION EACH SYSTEM 3.2.1. SEPARATION & COOLER SYSTEM 3.2.2. AMINE SYSTEM 3.2.3. CONDENSATE STABILIZING SYSTEM 3.2.4. DEW POINT CONTROL AND REFRIGERATION SYSTEM 3.2.5. GAS COMPRESSION SYSTEM 3.2.6. GAS TURBINE GENERATOR 3.2.7. AIR COMPRESSOR 3.2.8. ELECTRICAL MAP SUBAN GAS PLANT 3.3.
FINDINGS AND RECOMMENDATIONS
IV. ENERGY ASSESSMENT AT GRISSIK CENTRAL GAS PLANT 4.1. GENERAL PLANT OPERATION AND PERFORMANCE 4.1.1. GENERAL PLANT OPERATION OF GRISSIK GAS PLANT 4.1.2. GENERAL PLANT PERFORMANCE OF GRISSIK GAS PLANT 4.2. PERFORMANCE EVALUATION EACH SYSTEM 4.2.1. GAS PRETREATMENT AND MEMBRANE SYSTEM 4.2.2. AMINE SYSTEM 4.2.3. REFRIGERATION SYSTEM 4.2.4. CONDENSATE STABILIZING SYSTEM
Final Report
ID-N-GN-00000-00000-00068
Energy Management Audit / Assessment for PSC Corridor ConocoPhillips Indonesia
4.2.5. DEHYDRATION SYSTEM 4.2.6. WASTE HEAT BOILER 4.2.7. GAS TURBINE GENERATOR 4.2.8. AIR COMPRESSOR 4.2.9. ELECTRICAL MAP CENTRAL GRISSIK GAS PLANT 4.3. FINDINGS AND RECOMMENDATIONS
V. ENERGY ASSESSMENT AT RAWA OIL PLANT 5.1. GENERAL PLANT OPERATION AND PERFORMANCE 5.2. PERFORMANCE EVALUATION 5.2.1. GENERAL PERFORMANCE 5.2.2. PERFORMANCE EVALUATION OF MAIN EQUIPMENT 5.3. FINDINGS AND RECOMMENDATIONS
VI. PERFORMANCE MONITORING INDICATOR 6.1. EQUIPMENTS 6.1.1. Fired Heater 6.1.2. Waste Heat Boiler 6.1.3. Gas Turbine Generator 6.1.4. Residue Gas Compressor 6.1.5. Air Compressor 6.1.6. Propane compressor 6.1.7. Pumps 6.1.8. Air Cooler 6.1.9. Heat Exchanger 6.2.
SYSTEM
6.2.1. Gas Pretreatment 6.2.2. Membrane System 6.2.3. Amine System
Amine Contactor
Amine Regenerator
6.2.4. Dehydration System 6.2.5. Dew Point Control System
Page 4 of 109
Final Report
ID-N-GN-00000-00000-00068
Energy Management Audit / Assessment for PSC Corridor ConocoPhillips Indonesia
Gas Chiller
Low Temperature Separator
Page 5 of 109
6.2.6. Condensate Stabilizer 6.2.7. Depropanizer
APPENDICES 1.
SCHEDULE OF ENERGY ASSESSMENT/AUDIT
2.
MEASUREMENT DATA
3.
LABORATORY ANALYSIS
4.
LIST OF DATA HAS BEEN COLLECTED
5.
SPREAD SHEET OF EFFICIENCY AND ENERGY CONSUMPTION EQUIPMENTS
6.
SUBAN GAS PLANT
GRISSIK CENTRAL GAS PLANT
RAWA OIL PLANT
SPREAD SHEET OF PERFORMANCE MONITORING INDICATOR
EQUIPMENTS
SYSTEMS
7.
SIMULATION RESULT OF SUBAN GAS PLANT
8.
SIMULATION RESULT OF GRISSIK CENTRAL GAS PLANT
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ID-N-GN-00000-00000-00068 Page 6 of 109
I. INTRODUCTION As a part of energy management program, in the year of 2007 the Indonesia Business Unit of ConocoPhillips committed to develop plan regarding various efforts to conserve sources and to reutilize waste, energy utilization and to reduce emission reduction for each operating asset. Since 2004, emission level forecasts were generated as part of environmental performance report that shall be further followed up in actual action plans. This assessment is intended to guide the company in identifying energy-related business opportunities and appropriate methods and developing the strategic framework for realizing them. By performing this assessment / audit, it could also find emission reduction opportunities in onshore operating asset. The aim of this assessment is to identify where and how much energy is used in a facility and for determining energy saving and emission reduction opportunities in onshore operating asset. The objectives of this assessment / audit are as followed; 1. Provide clear direction or appropriate method as to potential inherent in a strategic approach to energy planning and management. 2. Define specific facilities that consume high energy and generate high emission. 3. To observe and evaluate the present situation of those plants in regards with energy consumption, process efficiency or performance and emission reduction opportunities. 4. Provide options based on a set of criteria (measures) and select the most promising options for implementation. 5. Provide recommendations and action plans in order to reduce energy consumption, increase plant efficiency and reduce emission rate in onshore operating assets by implementing energy diversification, energy efficiency and optimization and possibility to reuse energy waste. The Scope of this assessment / audit are as followed;, 1 Preliminary Energy Audit / Assessment which includes : Review and prepare additional information, Identification and inventory energy consumption and production data; Analyze data to determine which equipment will get high priority to be assessed and; prepare action plan to perform energy management audit / assessment 2 Performing Energy Audit / Assessment which includes : Identifies area of high energy usage and where energy waste occurs; Develop priorities for reducing energy waste and emission; Provides a criteria of measures which improvements could be implemented and; Generate spreadsheet for energy consumption per equipment
Final Report
ID-N-GN-00000-00000-00068
Energy Management Audit / Assessment for PSC Corridor ConocoPhillips Indonesia
Page 7 of 109
3 Establish Calculation Performance Monitoring Indicators per equipment and system 4 Provide Recommendation for Improvements a part of COPI energy management program To achieve the targets and to establish interactive cooperation of involved personnel without disturbing surveyed objects routine activities, the procedure of the Energy Assessment / Audit at Suban Gas Plant, Grisik Central Gas Plant and Rawa Oil Plant are as follows: Preparation of the plant survey, Field inspection and data collection, Data verification (of the data collected) Discussion Data analysis and evaluation Preliminary report, Discussion Field verification Interim Report/Draft Final Report Presentation, Final Report. The preparation of the plant survey has been held on 10 – 21 September 2007. The activity are includes define the boundaries, define data to be collected, define instruments / meter related to the data to be collected and prepare checklist for interview. The Field inspection and data collection has been held on 24 September – 5 October 2007. The activity are includes collection of technical data of main energy-consuming equipment, operation data, historical data, interview data, and direct measurement with portable equipment. Principally, the data collected should be enogh to calculate material and heat balance in each equipment. During data collecting period at Suban Gas Plant, Grissik Central Gas Plant and Rawa Oil Plant, not all the data requirement for analysis has been collected. Some of the data are completed from COPI Office Jakarta and the other data are completed during 2nd field inspection. Direct measurement are done for all fired heater at Suban Gas Plant and Waste Heat Boiler at Grissik Central Gas Plant. In order to crosscheck the data gathered are accurate and reliable before carrying out analyses, it is need to do the data verification. The data verification, has been held on 8 - 10 October 2007 and the discussion regarding the result of data verification has been held on 23 October 2007. Data analysis and evaluation has been held on 22 October – 23 November 2007. The activity of the analysis are includes preparation of calculation methodology, spread
Final Report
ID-N-GN-00000-00000-00068
Energy Management Audit / Assessment for PSC Corridor ConocoPhillips Indonesia
Page 8 of 109
sheet of equipment, develop heat and material balance, performance evaluation, identification/quantification of heat loss and calculation of energy conservation opportunities. The result of data analysis and evaluation are reported in the Preliminary Report on 26 November 2007 and discussion regarding this report has been held on 29 – 30 November 2007. 2nd field survey has been held on 3 – 7 December 2007 at Suban and Grissik. activity during 2nd field survey are includes :
The
Measurement of flue gas composition and temperature of Heater and Waste Heat Boiler. Electrical data records for rotating equipments. Presentation of draft final report has been held on 18-19 December 2007 The Schedule of Energy Assessment, data has been collected and measured, laboratory analysis are summarized in the appendices no.1 – no. 4.
Final Report
ID-N-GN-00000-00000-00068
Energy Management Audit / Assessment for PSC Corridor ConocoPhillips Indonesia
Page 9 of 109
II. METHODOLOGY 2.1. METHODOLOGY OF ENERGY ASSESSMENT/AUDIT Obviously, the Methodology of Energy Assessment / Audit at Suban Gas Plant, Grisik Gas Plant and Rawa Oil Plant will involve :
Collect and Analyze Energy-Usage Data
Review, identify and inventory energy consumption data
Identify the main energy consumption system and equipments
Performance evaluation and identify the main energy consumption equipment.
Quantity energy waste and emission.
Recommendation.
The information regarding plant operation has been collected during data collection period from 24 September to 5 October 2007. The data will be used in the analysis are include;
Daily Log Sheets
Computer logged data (for Suban and Grissik)
Laboratory analysis
Direct measurement during plant survey
Design data
After all the data has been collected, It is need to develop mass balance of each unit in order to verify the accuracy of flow meter reading. If there are discrepancy between mass inlet and outlet, ones of the mass flow should be adjusted, and than the data that has been verified will be used as data basis for development of heat and mass balance each equipment and system. By using Spreadsheet and Process Simulation, a plant model will be created to calculate performance aspect of the equipments and compare with design or available references. The plant model spreadsheet is constructed based on material and energy balance each equipment, energy efficiency and losses. Process Simulation used to develop material and energy balance for overall process gas plant. Especially on the fired heater and waste heat boiler the spreadsheet is constructed based on the calculation of energy efficiency, losses and emission level of each equipment. Based on the data that has been collected, performance of each equipment, efficiency level, energy waste and emission reduction potential of equipment will be calculated and quantified.
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ID-N-GN-00000-00000-00068 Page 10 of 109
Based on the energy and emission reduction potential level of each equipment and refer to technical and financial criteria, recommendation for improvement measure will be identified. All of the results of the evaluation / analysis will be discuss, present and reported to ConocoPhillips. The reporting of energy assessment / audit wil include preliminary report, interim/draft final report and final report. The preliminary report which covers : energy audit methodology, all data collected, all formula for calculations and preliminary findings. The interim/draft final report which covers : energy audit methodology, all data collected, energy performance analysis result, quantity of all energy waste and emission, energy waste and emission reduction opportunities and performance monitoring system. The final report which contains of: executive summary, evaluation result during audit / assessment, spreadsheet of energy consumption, spreadsheet of performance monitoring indicators and detail recommendation report.
2.2. METHODOLOGY OF CALCULATION The methodology of calculation are developed in two model which includes the calculation of equipment and the calculation of process system.
The Calculation of Equipment are includes : Fired Heater; Waste Heat Boiler; Gas Turbine Generator; Residual Compressor; Air Compressor; Propane Compressor; Pumps; Air Cooler; Heat Exchanger .
The Calculation of Process system are includes : Separation system; Amine System; Dehydration System; Condensate Stabilizer System, Depropanizer System and Refrigeration System
All of the calculation are explained regarding the efficiency and performance of each equipment and process system.
2.2.1.
CALCULATION OF EQUIPMENTS
2.2.1.a. Fired Heater The biggest energy consumption in the operation of gas plant is fired heater, so the evaluation of fired heater especially the efficiency and performance are very important in this assessment.
Final Report
ID-N-GN-00000-00000-00068
Energy Management Audit / Assessment for PSC Corridor ConocoPhillips Indonesia
Page 11 of 109 %O2, T stack
Conv. Rad.
Ta(ambient air temp)
Flue Gas
AIR
FIRED HEATER
FUEL
Proc Fluid
T out
Proc Fluid
Fluid Flow T in
Efficiency of Fired Heater can be calculated in two ways ie. :
Direct Method
Heat Loss Method *
* Refer to Enercon Handbook a. Direct Method : The step of calculation are as follows, Calculate heat duty of fired heater, k cal/hr Calculate LHV of fuel gas (refer to lab test), kcal/hr heat duty of fired heater Efficiency =
X 100% LHV of fuel gas
b. Heat Loss Method Fired Heater Efficiency are calculated based on the heat loss of : dry flue gas H2O from combustion of H2 H2O moisture from fuel gas H2O moisture from air radiation and convection (refer to design)
Final Report
ID-N-GN-00000-00000-00068
Energy Management Audit / Assessment for PSC Corridor ConocoPhillips Indonesia
Page 12 of 109
The step of calculation of heat loss method in the fired heater are as follows, a.
Measure Ta, Tstack and % O2 in flue gas
b. Calculate combustion air for stoichiometry condition c. Calculate excess air at % O2 as measure d. Calculate flue gas flow, kg/h (flue gas flow = fuel + comb air stoch + excess air) e. Calculate flue gas loss, kcal/hr (flue gas loss = flue gas flow x Cp x (Tst – Ta)) LHV of Flue Gas – flue gas loss – Rad & Conv Loss** Efficiency =
X 100% LHV of Fuel Gas ** Refer to design condition
The efficiency calculated from heat loss method can be used to check the accuracy of fuel gas flow meter recorded at each fired heater. The step of calculation are as follows : calculate heat duty of fired heater based on the different enthalpy of BFW (steam) inlet and outlet. calculate the heat release of fired heater based on the calculated efficiency (ie. the heat duty divided by efficiency). heat release from the calculation can be used to check the accuracy of fuel gas flow meter recorded at each fired heater
2.2.1.b. Waste Heat Boiler (WHB) The calculation methodology of WHB is similar with fired heater, the small different is in the calculation of steam flow which is calculated based on BFW flow rate minus blow down flow rate. Efficiency of Waste Heat Boiler also can be calculated in two ways ie. : Direct Method Heat Loss Method * * Refer to Enercon Handbook a.
Direct Method
Efficiency =
(Hst – HBFW) x ST.Flow
L.H.V. (Fuel Gas + Pem Gas + Acid Gas)
X 100%
Final Report
ID-N-GN-00000-00000-00068
Energy Management Audit / Assessment for PSC Corridor ConocoPhillips Indonesia
Page 13 of 109
% O2 , Tstack
Ta (ambient air temp) Flue Gas
Conv. Rad. AIR
Fuel Gas
Acid Gas
WASTE HEAT BOILER
Steam
Flow, P, Tsteam
Permeat Gas
Water
Blow Down
b. Heat Loss Method The step of calculation are as follows, a. Measure Ta, T stack and % O2 in flue gas b. Calculate combustion air of acid gas, permeate gas and fuel gas for stochiometry condition c. Calculate excess air at actual condition d. Calculate dry flue gas flow at actual conditions, kg/hr e. Calculate total loss, kcal/hr Total loss = dry flue gas loss + blow down loss + rad & conv. loss Dry flue gas
= flue gas flow x Cp x (Tst – Ta)
Blow down loss = % blow down *x ST. Flow x ( H Saturate – HBFW) *Assume % blow down (± 2%) ** Refer to design condition
LHV (Total) – Total loss Efficiency =
X 100% LHV (Total)
Final Report
ID-N-GN-00000-00000-00068
Energy Management Audit / Assessment for PSC Corridor ConocoPhillips Indonesia
Page 14 of 109
2.2.1.c. Gas Turbine Generator Conv Rad.
Flue Gas
AIR
GTG
FUEL
BH P
G
ELECTR IC
kWh x 860.1 x 3.968 Efficiency
=
X 100% LHV Fuel Gas x Flow F.G (Btu/h)
LHV Fuel Gas x Flow Fuel Gas Performance
= kWh
Efficiency of Gas Turbine also can be calculated by using heat loss method, which include heat loss of : dry flue gas H2O from combustion of H2 H2O moisture from fuel gas H2O moisture from air radiation and convection (refer to design)
2.2.1.d. Residual Gas Compressor Mechanical pressure
Fuel gas input compressor
Energy loss
work
derived
from
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ID-N-GN-00000-00000-00068
Energy Management Audit / Assessment for PSC Corridor ConocoPhillips Indonesia
Page 15 of 109
Mechanical work Efficiency = Heat from fuel gas input
Mechanical Work
ZRT *= Qx x MW n
n
Pd
n-1 ) n
x ((
–1
- 1 ) / (33,000 x 0.77)
Ps
Q = Gas Flow, lb / mnt R = Gas Constant MW = Molecular weight T = inlet Temperature, oR Z = Compressibility Factor n = Polytropic Factor Pd = Discharge Pressure Ps = Suction Pressure * Refer to Pipeline Handbook Efficiency of Gas Turbine also can be calculated by using heat loss methode, which include heat loss of : dry flue gas H2O from combustion of H2 H2O moisture from fuel gas H2O moisture from air radiation and convection (refer to design)
2.2.1.e. Air compressor Electric input
Mechanical pressure
power
work
derived
from
Energy loss
Mechanical work Efficiency = Electric power input 1.4
Mechanical Work * =
Ps Q x
0.4
Pd x((
6120
Ps
O x 10.000
0.4
)1.4
- 1) x
0.8 x 0.95
Final Report
ID-N-GN-00000-00000-00068
Energy Management Audit / Assessment for PSC Corridor ConocoPhillips Indonesia
Page 16 of 109
Ps = Inlet Press Kgf/ cm2 Q = Air Flow m3 / mnt R = Press ratio P2 / P1 O = Factor ( 1.0 – 1.5 ) * Refer to Energy Conservation Handbook – ECC Japan
2.2.1.f. Propane compressor
Electric input
Mechanical pressure
power
work
derived
from
Energy loss
Mechanical work Efficiency = Heat from fuel gas input
Mechanical Work * = Q x
ZRT x MW
Q = Gas Flow, lb / mnt R = Gas Constant MW = Molecular weight T = inlet Temperature, oR Z = Compressibility Factor n = Polytropic Factor Pd = Discharge Pressure Ps = Suction Pressure * Refer to Pipeline Handbook
n
Pd x ((
n–1
)
Ps
n-1 n
- 1 ) / (33,000 x 0.77)
Final Report
ID-N-GN-00000-00000-00068
Energy Management Audit / Assessment for PSC Corridor ConocoPhillips Indonesia
Page 17 of 109
2.2.1.g. Gas Chiller From Gas to Gas HE Gas
H2
T1
To Propane Compressor
Gas Chiller H1 Propane
To
To Low Temperatur Separator
From Propane Acumulator
Cooling Load* = (GF x Cp g (To – Ti)) + (CF x Cpc (To – Ti)) + (f x CF x Latent Heat) Cooling Load COP Actual* = compressor motor power (actual) Cp g GF CF Cp c f
= Specific Heat gas at P & T operation = Gas Flow = Condensate Flow = Specific Heat condensate = fraction of condensate
* Refer to ASHRAE Handbook (fundamentals)
2.2.1.h. Pumps Energy loss
Electric power input
Mechanical work (capacity, total head)
Obtained from curves into data sheet
Mechanical work Efficiency = Electric power input
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ID-N-GN-00000-00000-00068
Energy Management Audit / Assessment for PSC Corridor ConocoPhillips Indonesia
Page 18 of 109
Mechanical Work (Pw) *: Pw (hp) = fv.(Sg x Ht) / 3960 Sg = Specific grafity Ht = Total Head (feet) Fv = Correction factor related to viscousity
Ht (psia) = Dp – Sp Sp = Suction pressure (psia) Dp = Discharge pressure (psia) Ht (feet) = 2.31 x Ht (psia) * Refer to Pump Handbook - Karrasik, Krutzsch
2.2.1.i. Air cooler T in h
Energy loss
T out l
m, p Electric input
power
T in l
Efficiency =
T out
h
Cooling Load Electric power input
Cooling Load = Q Q = m (H) Where m : Flow rate H : Enthalpy different Fouling Factor Performance are calculated based on the value of Overall heat transfer coefficient (Uo): Uo = Q / (A Tlm) Q
: actual heat load (Q act)
A
: Heat transfer Area
Final Report
ID-N-GN-00000-00000-00068
Energy Management Audit / Assessment for PSC Corridor ConocoPhillips Indonesia
Page 19 of 109
Tlm : Log Mean Temperature Different
2.2.1.j. Heat Exchanger Evaluation of heat exchanger are include the performance of heat transfer coefficient compare to design condition. If the heat transfer coefficient are lower it is could be caused by fouling or there are change in quality or quantity in the process side. VAP. OUT
VAP. OUT
VENT STEAM IN
LIQ. OUT
VAP. IN
VAP. IN
CONDENSATE OUT
a. Performance Calculation: Performance = [Heat load based on actual data calculation] [Heat load based on basic design calculation] = Q act / Q design b. Fouling Factor Performance are calculated based on the value of Overall heat transfer coefficient (Uo): Uo = Q / (A Tlm) Q
: actual heat load (Q act)
A
: Heat transfer Area
Tlm : Log Mean Temperature Different
Final Report
ID-N-GN-00000-00000-00068
Energy Management Audit / Assessment for PSC Corridor ConocoPhillips Indonesia
Page 20 of 109
2.2.2. CALCULATION OF SYSTEMS 2.2.2.a. Separation System a. TSA UNIT FEED GAS
ADSORBTION COLUMN
TREATED GAS
Adsorption Rate =
(mole C6+ Feed - mole C6+ Treated)
(lbmole/lbmole)
Mole C6+ Feed TSA Regeneration Rate =
BTU
(BTU/lbmole)
(mole C6+ Feed - mole C6+ Treated) b. Membrane Unit PROCESS GAS
FEED GAS
MEMBRANE
PERMEATE GAS
Membrane separation rate = mole CO2 in Permeate Gas
(lbmole/ lbmole)
Mole CO2 in Feed Gas HC Slipped rate =
mole HC in Permeate Gas Mole HC in Feed Gas
(lbmole/ lb mole)
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ID-N-GN-00000-00000-00068
Energy Management Audit / Assessment for PSC Corridor ConocoPhillips Indonesia
Page 21 of 109
2.2.2.b. Amine System a. Amine Contactor TREATED GAS LEAN AMINE
FEED GAS
AMINE CONTACTOR
RICH AMINE
Absorbtion Rate = ``mole-CO2 absorbed
(lbmole/lbmole) and (lb/lb)
Mole pure lean amine Mole Weight of pure Lean Amine are dynamic should be calculated
b. Amine Regenerator ACID GAS RICH AMINE
STEAM
AMINE REGENERATOR
CONDENSATE LEAN AMINE
Amine Regeneration Rate =
BTU(steam) CO2 removed
(BTU/lbmole -CO2)
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Energy Management Audit / Assessment for PSC Corridor ConocoPhillips Indonesia
Page 22 of 109
2.2.2.c. Dehydration System GAS
TREATED GAS
DEHYDRATION PACKAGE
GLYCOL MAKE-UP FUEL GAS CONSUMPTION GLYCOL CYCLE
MOISTURE OUT
WATER VAPOR OUT
Absorbtion Rate = lbs-H2O absorbed
(lbmole/GPM) and (Lb-H2O/Lb-Glycol)
GPM Pure Lean Glycol
Glycol Regeneration Rate =
BTU (Fuel Gas) Moisture removed
2.2.2.d. Condensate Stabilizer LP FUEL GAS
FEED LIQUID
LIGHT HC
STEAM
CONDENSATE STABILIZATION
STEAM CONDENSATE CONDENSATE
(BTU/lb –H2O)
Final Report
ID-N-GN-00000-00000-00068
Energy Management Audit / Assessment for PSC Corridor ConocoPhillips Indonesia
Page 23 of 109
Yield of Stabilization = BBL Treated Condensate
(bbl/ bbl)
BBL Raw Condensate Quantity
total
of
condensate
Stabilizer Performance =
refer
to
percentage
BTU(steam)
of
feed
(BTU/ bbl)
BBL Treated Condensate flow
2.2.2.e. Depropanizer
PROPANE PRODUCT
FEED LIQUID
DEPROPANIZER
CONDENSATE PRODUCT
Yield of Stabilization =
mole Propane product
(lbmole/ lbmole)
Mole Feed HC
Deprop. Performance =
kWh(Electric) Lbmole Propane product
(kWh/ lbmol)
inlet
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Energy Management Audit / Assessment for PSC Corridor ConocoPhillips Indonesia
Page 24 of 109
III. ENERGY ASSESSMENT AT SUBAN GAS PLANT 3.1. GENERAL PLANT OPERATION AND PERFORMANCE 3.1.1. GENERAL PLANT OPERATION OF SUBAN GAS PLANT Gas from well head is delivered to CGP with flow line about 1 km length to the separation unit, HP Production Separator. Because gas produced from HP Production Separator still contain CO2, H2S and H2O in high concentration, it has to be treated by CO2/H2S Removal Package and Dehydration Unit to meet the gas delivery condition requirements. A selective Amine based on MDEA solvent shall be provided for removal of CO2 & H2S in feed gas from Gas Scrubber, to meet the sales gas specification. The system shall also include the regeneration of the MDEA solvent used to absorb H2S. Acid Gas Removal Unit is installed with capacity 700 MMSCFD (total 4 trains) Sour Gas and should be removed CO2 / H2S until meet sales gas specification (3%). Acid gas released from Acid Gas Removal unit should be routed to The treated gas scrubber Unit with enough pressure approximately 1400 psig to ensure Acid Gas have enough pressure for next processes. A Ethylene Glycol based gas dehydration unit shall be provided to dehydrate gas from amine unit to achieve the sales gas specification (5-7 Lb/SCF). EG Dehydration Unit is with capacity 700 MMSCFD (Total 4 trains). The treated gas will be compressed by GTC (Gas To Compressor) with capacity 235 MMSCFD (There are 4 GTC, each of GTC has 235 MMSCFD Capacity) to increase sales gas pressure until 1280 psig. The other part of treated gas is delivered to Fuel Gas Filter as Fuel Gas for Gas Turbine Generator (GTG),Gas Turbine Compressor or as fuel gas for the CPP gas engine equipment. The Condensate from Horizontal Separator is routed to Stabilizer Feed Drum for further separation process from carry over gas. To meet the Condensate Delivery Condition, the condensate produced is stabilized with Condensate Stabilization Units, with capacity are 44,349 Lb/hr for train 1 & 82,211 Lb/hr for train 2, and then stored in the Condensate Storage Tank with capacity is 30,000 BBL. The condensate pumps will be used to dispatch the condensate to Condensate Truck Loading. Water collect from separation unit is automatically drained to a common header and then to be processed in the produced water treatment system. Blow down system is used for over pressure protection or for reducing the CGP pressure either in emergency (ESD) or at the operator’s discretion in a shutdown and blocked condition. The blow down system shall be capable of relieving the entire CPP
Final Report
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Energy Management Audit / Assessment for PSC Corridor ConocoPhillips Indonesia
Page 25 of 109
equipments from the highest possible shut-in pressure down to half times in 15 minutes. The blow down system is arranged with automatic blow down valves which is fitted at the downstream of the separation units and at the discharge of CNG Compressor to blow down through the HP Flare vent line. Localized venting of gas to atmosphere is also provided for piping and vessels via manual vents and pressure relieving devices, i.e. relief valves. Fire water will be supplied from the fire water make up pump to a Fire Water Pond. Fire water is distributed to the fire water main ring by three fire water pumps (two pumps act as main pumps, and one as jockey) in a duty standby arrangement. Foam tank and foam pump are provided to protect the condensate storage tank. The CGP shall be fully equipped with fire and gas detection system. All electric instruments shall be hard-wired to CGP Control Room and communicated to Programmable Logic Control (PLC) and Human Machine Interface (HMI) to monitor and control the process. The simple process flow of Suban field is shown with block diagram in figure 2.1 Gas to Flare 7
Acid Gas 4
T Suban Gas Well
1
T
T
2
Gas Seperation Unit
3
Amine System
T TEG Dehydration Unit
T
5
6
Sales Gas
Residual Compressor
9
8
T
10
Condensate
Condensate Stabilizer
11
Liquid water
Figure 3.1. Simple Block Diagram Gas from Inlet Separator still contains CO2 and H2O in high concentration. The gas shall be treated in purification unit before the gas is delivered to Grissik Central Gas Processing plant by Pipe line system. 3.1.2. GENERAL PLANT PERFORMANCE OF SUBAN GAS PLANT The Energy source of Suban Gas Plant actually are fuel gas from Scrubber which is consumed by GTG, GTC and Fired Heater (thermal oxidizer, amine re-boiler heater and heat medium heater). Based on 29 September 2007, the fuel gas consumption for each equipment are shown in table below;
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Table 3-1 : Fuel gas consumption
Fuel Gas to Flare 248-FQI-2131B
D
0.200 MMSCFD
248-FQI-2231B
D
1.000 MMSCFD
C
1.200 MMSCFD
225-H-102
D
0.314 MMSCFD
225-H-202
D
0.161 MMSCFD
TOTAL Fuel Gas to Heater Thermal Oxidixer
0.475 MMSCFD Amine Reb Heater 225-H-111
D
0.620 MMSCFD
225-H-211
D
0.563 MMSCFD 1.183 MMSCFD
Heat Medium Heater 257-H-101A
D
0.121 MMSCFD
257-H-101B
D
0.016 MMSCFD
257-H-201A
D
0.152 MMSCFD
257-H-201B
D
0.138 MMSCFD
C
0.428 MMSCFD
Fuel gas to GTG 247-GT-101A
-
247-GT-101B
-
247-GT-201A
C
0.900 MMSCFD
247-GT-201B
C
0.900 MMSCFD
247-GT-201C
C
0.900 MMSCFD
D
2.700 MMSCFD
242-KT-101
D
0.590 MMSCFD
242-KT-201
D
- MMSCFD
242-KT-301
D
0.730 MMSCFD
242-KT-401
D
0.700 MMSCFD
C
1.430 MMSCFD
C
6.22 MMSCFD
Fuel gas to GTC
TOTAL - 2
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C
7.42 MMSCFD
Note : D = Data ; C = Calculated
The total fuel consumption at 29 September 2007 (including fuel gas to flare) is 7.42 MMSCFD. There are two type of fuel gas used in Suban Gas Plant ie. : LP Fuel gas and HP Fuel gas. LP Fuel gas is used to fired heater and HP Fuel gas is used to GTG and GTC. The heating value (HHV) of LP Fuel gas is around 1,574 Btu/SCF and HP Fuel Gas is around 1,130 Btu/SCF. Based on the heat balance calculation of Fired Heater, GTG and GTC, the energy picture on 29 September 2007 which are includes Heat Release, Heat Absorb, Heat Loss and CO2 emission are as follows : Table 3-2 : The energy picture of Suban Gas Plant HEAT RELEASE, Btu/hr
STACK LOSS, Btu/hr
HEAT ABSORB, Btu/hr
TEMP, Deg F
CO2 Emission, lb/hr
FLARE 248-FQI-2131B
13,200,110
0
11,898,856
1,472
1,849
248-FQI-2231B
66,000,552
0
59,494,279
1,472
9,243
225-H-102
38,486,293
0
35,495,414
932
81,738
225-H-202
10,602,175
0
8,303,983
2,012
1,488
225-H-111
40,771,370
32,203,736
9,055,361
405
5,730
225-H-211
37,035,660
29,160,613
8,988,198
361
5,204
257-H-101A
8,017,576
5,448,456
2,338,395
486
1,123
257-H-101B
0
0
0
0
0
257-H-201A
10,004,765
7,479,528
2,322,751
543
1,405
257-H-201B
9,088,243
6,758,329
2,473,720
500
1,275
247-GT-101A
0
0
0
0
0
247-GT-101B
0
0
0
0
0
247-GT-201A
42,371,386
7,714,245
33,163,974
916
5,611
HEATER Thermal Oxidizer
Amine Reboiler H-M Heater
Heat Medium Heater
GTG
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247-GT-201B
42,371,386
7,721,419
29,310,275
921
5,611
247-GT-201C
42,371,386
7,702,911
29,397,944
925
5,611
242-K-101
28,157,031
4,816,837
21,555,786
1,213
1,668
242-K-201
0
0
0
0
0
242-K-301
34,800,050
7,277,193
22,755,271
1,261
2,064
242-K-401
33,379,354
6,924,878
21,806,787
1,237
1,979
123,208,143 298,360,993
689
131,598
GTC
TOTAL
456,657,336
Plant Performance : The production rate at 29 September 2007 is 94,023 BOE which include 517 MMSCFD of sales gas (note : 1 SCF = 6000 BOE) and 7,823 barrel of condensate, and total heat released including flare gas is 456,657,336 Btu/hr. The performance of Suban Gas Plant as shown in table below : Table 3-3 : Suban Gas Plant performance
PRODUCTION RATE Sales Gas = =
517.20 MMSCFD 86,200.00 BOE
Condensate =
7,823.00 BOE
Total Prod =>
94,023.00 BOE
ENERGY CONSUME Excluding Flare Including Flare ENERGY INTENSITY Excluding Flare Including Flare
377,456,674.27 456,657,336.12 Btu/hr
4,014.51 Btu/BOE 4,856.87 Btu/BOE
It shown that the energy consumption to produce one BOE (= Energy Intensity) at Suban Gas Plant is 4,014.51 Btu/BOE (Excluding Flare) or 4,856 Btu/BOE (including flare) . (Note : No design data to compare the Actual Energy Intensity).
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This condition can not compare with another gas plant, because every plant have its own characteristic. The important thing is how to reduce energy consumption based on its own characteristic.
3.2 PERFORMANCE EVALUATION EACH SYSTEM 3.2.1 SEPARATION & COOLER SYSTEM A. DESCRIPTION Gas from manifold enters the Inlet Separator which will separate gas from the bulk liquid. The separator are designed for gas flow 160 MMSCFD (for train 1,2) and 214 MMSCFD (for train 3,4), whereas liquid flow are designed about 1973 gallon/min ( for train 1,2) and 2640 gallon/min (for train 3,4) . Production Separator will be normally operated at pressure 1188 psig and temperature 240 °F. The Inlet Separator is a three phase separator to provide primary gas-condensatewater separation. This is to ensure that no significant carry-over/under of the respective phases. B. PERFORMANCE Main equipment of Separation and cooler system are include : Inlet Cooler 215-E101A/B, 215-E-201A/B, 215-E-401A/B and 215-E-301A/B. The performance of main equipment are as follows. Table 3-4 : Performance of Inlet Cooler
215-E-101
215-E-201
215-E-301
215-E-401
DESIGN
Temp inlet, F
220.00
218.00
220.00
220.00
240.00
Temp outlet, F
110.00
110.00
110.00
110.00
115.00
Flowrate, lb/hr
323,297
323,297
486,956
486,956
476,174
Temp inlet, F
93.20
93.20
93.20
93.20
95.00
Temp outlet, F
113.00
113.00
114.00
114.00
131.60
Delta T LMTD
45.96
45.96
46.54
46.54
52.30
HEAT DUTY, MMBtu/hr
28.37
28.37
43.04
43.04
50.01
HEAT TRANSFER RATE, BTU/HR.FT2.F
4.46
4.46
3.08
3.08
5.09
INLET GAS COOLER
AIR COOLANT
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ELECTRIC CONSUMPTION, KW
13.13
13.13
13.13
13.13
16.41
ACTUAL FAN OPERATED
4.00
4.00
4.00
4.00
4.00
CALCULATE FAN OPERATED
3.04
3.04
3.44
3.44
4.00
The above table shows that the actual heat duty of each inlet cooler are less than design. It means that the actual cooling rate needs less energy than design. The heat duty on Train #1 and #2 are operated at 60% of design. The heat transfer rates of exchangers are closed to the design. Based on actual condition, the performance of cooler is still in good condition. Losses at inlet cooler are described from cooler outlet temperature. If the outlet temperature higher than the design outlet temperature, it means the cooling rate is not good. At this case, the exchangers are still in good condition. 3.2.2 AMINE SYSTEM A. DESCRIPTION The feed gas from Inlet Separator contains CO2 5.42% by mole and small of H2S content. A typical feed condition is 114 oF and 1163 psia; The products specifications is designed for the CO2 content is 3.4 % by mole respectively. The acid gas removal package uses activated methyl-di ethanolamine (MDEA) to remove the acid gases (H2S & CO2) by means of counter-current mass transfer in an Amine Contactor unit. The gas from the inlet separator will be fed to the Acid Gas Removal Package. As the inlet gas is a saturated gas stream, there is a possibility of hydrocarbon and water condensation prior to inlet of the amine contactor. To minimise liquid carry-over to the system, a Horizontal filter unit is provided. The horizontal filter unit will have level control drain-off valves, both on the upstream and downstream of the filter element, whereby the liquid is sent to the flare system for disposal. The liquid free gas from the Horizontal filter is then fed to the Amine Contactor, whereby the gas is in contact with lean aqueous MDEA solution (amine). The enhanced solubility of the acid gas in lean amine would soluble the acid gas component, thus stripping it of H2S and CO2. The rich amine from the contactors flows to the rich amine flash drums. The rich amine flows under level/flow control through the lean/rich amine exchangers where it is heated to about 206 oF by heat exchange with the hot lean amine from the two regenerators. The rich amine feeds the regenerator above the stripping section which contains stainless steel structured packing. CO2 and H2S are stripped from the rich solution by heat produced in the regenerator re-boilers.
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B. PERFORMANCE Main equipment of Amine System are includes : Amine Heat Medium Heater (225-H-111; 225-H-211); Amine Reg. Reboiler (225-E-102 A/B, 225-E-202 A/B); Treated Gas Cooler (225-E-105, 225-E -205, 225-E -305, 225-E -405), Amine Charge Pump (225-P-102A/B/C), Amine Booster Pump (225-P-101A/B/C) and Amine Heat Medium Circ. Pump (225-P-111A/B/C, 211A/B/C). The performance of main equipment of Amine System are as follows. Amine Heat Medium Heater : Table 3-5 : Performance of Amine Heat Medium Heater 225-H-111
225-H-211
DESIGN
0.62
0.56
1.13
404.60
361.40
412.00
O2, %
6.50
9.20
3.00
Excess Air, %
41.00
83.15
15.27
2,285,233
2,004,973
2,910,000
T in, F
257
257
285
T out, F
270
270
305
P in, Psi
280
280
285
P out, Psi
270
270
274
Heat absorption (LHV), MMBtu/hr
31.81
28.70
57.98
Heat absorption (HHV), MMBtu/hr
32.20
28.94
58.12
Efficiency (LHV), %
85.80
84.87
89.11
Efficiency (HHV), %
78.95
78.06
81.18
5,730
5,203
10,609
FUEL, Flow, MMSCFD FLUE GAS T out, F
HOT WATER lb/hr
PERFORMANCE
CO2 EMISSION CO2 Emission from fuel gas, lb/hr
The heat duty of Amine H-M Heater was only 55 % and 50 % load compare to design condition.
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The efficiency by using heat loss method are calculated based on the flue gas composition and temperature measurement by using portable analyzer and thermometer. No meter of temperature and O2 analyzer in flue gas line. The flue gas temperature at actual condition is lower than design condition but the excess air is too high and the operating load is too low. The efficiency at actual condition is around 85 % compare to design condition which is 89 %. This efficiency is low compare to design condition, it is caused by higher excess air and lower operating load. Amine Regenerator Reboiler: Table 3-6 : Performance of Amine Regenerator Reboiler
225-E-102A/B
225-E-202A/B
DESIGN
Pressure, psig
280.00
8.70
235.00
Temp. inlet (F)
275.00
278
305.00
Temp. outlet (F)
250.00
250
285.00
1,025,912
894,957
1,412,550
Temp. inlet Regenerator, F
212.00
205
249.1
Temp. outlet Regenerator, F
220.00
240
254.3
Delta T LMTD
45.98
41.40
42.88
26,313,323
25,711,215
29,084,405
85
93
101
HEAT MEDIUM SIDE (TUBE)
Flowrate Heat Medium, Lb/hr AMINE SIDE (SHELL)
HEAT DUTY, Btu/hr HEAT TRANSFER RATE SERVICE, 2 BTU/HR.FT .degF
The above table shows that the heat duty operated closed to the design. The difference between actual heat duty and design only 10%. The operated temperature higher than design value. The performance of heat exchanger can be evaluated from the value of overall heat transfer rate (U). The U at actual condition is 85 BTU/(Hr/Ft2.F) and 93 BTU/(Hr/Ft2.F) compare to design value which is 101 BTU/(Hr/Ft2.F..
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Treated Gas Cooler : Table 3-7 : Performance of Treated Gas Cooler 225-E-105
225-E-205
DESIGN
Pressure,psig
1206
1202
1162
Temp inlet, F
147.90
152.00
139.80
Temp outlet, F
120.70
125.70
120.00
Flowrateof Acid gas, MMSCFD
138.92
119.56
151.80
Temp inlet, F
92.00
92.00
95.00
Temp outlet, F
110.00
112.00
118.40
Delta T LMTD
33.09
36.76
26.50
4,622,698
3,873,942
4,300,000
56.79
55.61
59.68
2
2
2
CALCULATE FAN OPERATED
2.1
1.8
2.0
HEAT TRANSFER RATE, BTU/HR.FT2.F
3.9
3.0
5.2
225-E-305
225-E-405
DESIGN
Pressure,psig
1206
OFF
1162
Temp inlet, F
147.90
OFF
139.80
Temp outlet, F
126.50
OFF
120.00
Flowrateof Acid gas, MMSCFD
204.82
OFF
203.40
Temp inlet, F
92.00
OFF
95.00
Temp outlet, F
110.00
OFF
118.40
Delta T LMTD
33.09
OFF
26.5/23
5,346,317
OFF
5,810,000
WATER+ACID GAS
AIR COOLANT
HEAT DUTY, Btu/hr ELECTRIC CONSUMPTION, KW ACTUAL FAN OPERATED
WATER+ACID GAS
AIR COOLANT
HEAT DUTY, Btu/hr
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59.15
OFF
59.68
2
OFF
2
CALCULATE FAN OPERATED
1.9
OFF
2.0
HEAT TRANSFER RATE, BTU/HR.FT2.F
4.5
OFF
5.4
ACTUAL FAN OPERATED
The above table shows that the actual heat duty closed to the design. The difference between actual and design only +/- 10%. Electric power consumption for motor fan drivers also close to design with deviance not more than 7%. The fan running at actual condition also same as design, each exchanger have 2 (two) fans running. This indicates that the process is in good condition. Temperatures of gas outlet from these exchangers all meet the specification process condition, 120.7 and 125.7 deg F for train#1 and #2, and 126 deg F for train#3 refer to the design is 120 and 203.4 deg F respectively. The performance of heat exchanger can be evaluated from the value of overall heat transfer rate (U). The U at operating condition give value of 3.9 and 3.0 BTU/(Hr/Ft2.F) for train#1 and train#2 and 4.5 BTU/(Hr/Ft2.F) for train#3. The design value is 5.2 and 5.4 BTU/(Hr/Ft2.F). Regenerator Reflux Condenser : Table 3-8 : Performance of Regenerator Reflux Condenser 225-E-101
225-E-201
DESIGN
Pressure,psig
11.9
12
26.9
Temp inlet, F
194.40
226.4
205.00
Temp outlet, F
135.60
120.5
120.00
5.50
7.3
8.76
Temp inlet, F
92.00
92
92.00
Temp outlet, F
140.00
145
144.00
Delta T LMTD
48.80
50.41
48.60
9,259,749
13,234,590
16,824,662
17.67
40.04
44.00
2
4
4
CALCULATE FAN OPERATED
2.2
3.1
4.0
HEAT TRANSFER RATE,
1.9
2.7
3.0
WATER+ACID GAS
Flowrateof Acid gas, MMSCFD AIR COOLANT
HEAT DUTY, Btu/hr ELECTRIC CONSUMPTION, KW ACTUAL FAN OPERATED
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BTU/HR.FT2.F
The above table shows that regenerator reflux condenser is operated at 55% load for 225-E-101 and 78% load for 225-E-201 compare to design condition. This caused by the flow rate of acid gas are 62% and 83% compare to design condition. Actual fan operated for the cooler 225-E-101 is 2 fans running, but the calculated fan should be operated is 3 fans (2.2). This causes the temperature of the outlet of cooler is higher than the design. Design value state the temperature is 120 deg F, but this cooler operated at 135 deg F. The outlet temperature of cooler 225-E-201 is meet to the design value. The U (overall heat transfer rate) at actual condition is 1.9 and 2.7 BTU/(Hr/Ft2.F) for 225-E-101 and 225-E-201 compare to design is 3.0 BTU/(Hr/Ft2.F). Lean Amine Cooler : Table 3-9 : Performance of Lean Amine Cooler
225-E-103
225-E-203
DESIGN
Pressure, psig
135.00
135.00
129.43
Temp inlet, F
180.00
180
182.90
Temp outlet, F
130.00
130
125.00
Temp inlet, F
94.00
94
95.00
Temp outlet, F
135.00
134
137.20
Delta T LMTD
40.33
40.80
37.30
HEAT DUTY, Btu/hr
16,784,037
16,254,308
31,537,959
ELECTRIC CONSUMPTION, KW
35.35
35.35
76.00
ACTUAL FAN OPERATED
2.00
2.00
4.00
CALCULATE FAN OPERATED
2.1
2.1
4.0
HEAT TRANSFER RATE, BTU/(HR.Ft2.degF)
1.6
1.5
1.8
LEAN AMINE SIDE
AIR COOLANT SIDE
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The above table shows that the actual heat duty of 225-E-103 and 225-E-203 are rated at 50% compare to the design. This caused by the flow rate of lean amine only about 50% - 60% from design capacity. The flow rate of lean amine affects to the power required of fan cooler driver. The actual operated fans for 225-E-103 and 225-E-203 are 2 fans compare to 4 fans for design. This condition affects the performance of cooler, especially with heat transfer rate. The value of U (overall heat transfer rate) at actual condition is 1.6 BTU/(Hr/Ft2.F) for 225-E-103 and 1.5 for 225-E-203 compare to design 1.8 BTU/(Hr/Ft2.. This difference indicated that the performance of coolers are still have good performance. Rich-Lean Amine Exchanger : Table 3-10 : Performance of Rich-Lean Amine Exchanger
225-E-104A-B
225-E-204A-B
DESIGN
Pressure, psig
90.00
100.00
100.00
Temp inlet, F
105.00
105.00
138.20
Temp outlet, F
190.00
210.00
210.20
Flowrate of Rich Amine, USGPM
458.20
483.40
1,138.90
Temp inlet, F
250.00
250.00
253.20
Temp outlet, F
210.00
210.00
182.30
Delta T LMTD
80.41
67.35
43.55
16,403,302
20,960,808
39,616,136
N/A
N/A
N/A
RICH AMINE SIDE
LEAN AMINE SIDE
HEAT DUTY, Btu/hr HEAT TRANSFER RATE, BTU/(Hr/Ft2.F)
The flow rate of fluid in Rich-lean amine exchanger is about 40% from design capacity. This will affect the heat load for these exchangers at 40% for 225-E-103 and 50% for 225-E-203. LMTD between hot fluid and cold fluid are higher than the design specification. This case will affect the heat transfer rate for these exchangers. The temperature inlet of Rich amine is lower compare to the design value. This is indicate the amine contacting process in the field running on lower temperature than the design specification.
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Lean Amine Charge Pump : Table 3-11 : Performance of Lean Amine Charge Pump
DESCRIPTION
UNIT
225-P-102A
225-P-102B
225-P-102C
Design
value
value
value
value
specific gravity
1.05
1.05
OFF
1.00
Temperature
F
137.00
137.00
OFF
125.00
suction pressure
psia
111.00
111.00
OFF
N/A
discharge pressure
psia
1550.00
1550.00
OFF
N/A
flow
GPM
265.00
265.00
OFF
1165.00
Total head
ft
3180.05
3180.05
OFF
2550.00
Electric motor power
HP
575.00
575.00
OFF
1000.00
Mechanical work
HP
227.34
227.34
OFF
766.69
Efficiency
%
39.54
39.54
OFF
76.67
Two Amine Charge pumps were running at 265 GPM each, and had efficiency of 39.54%. This efficiency is quite low compare with 76.67% efficiency at design condition. This is due to very low flow rate they handled. The 76.67% efficiency can be achieved at 1165 GPM. The sum of fluid flow rate for each pump (530 GPM) is still far below the design flow rate for one pump. Higher efficiency could be achieved should the fluid flowing is handled by one pump only. Amine Reboiler H/M Circulation Pump : Table 3-12 : Performance of Amine Reboiler H/M Circulation Pump
DESCRIPTION
UNIT
specific gravity
225-P111A
225-P111B
225-P211A
225-P211B
Design
1.00
1.00
1.00
1.00
1.00
Temperature
F
137.00
137.00
137.00
137.00
285.00
suction pressure
psia
205.70
205.70
205.70
205.70
N/A
discharge pressure
psia
294.70
294.70
294.70
294.70
N/A
flow
GPM
2211.00
2186.00
1911.00
1911.00
3044.00
Total head
ft
205.59
205.59
205.59
205.59
180.00
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Electric motor power
HP
168.00
168.00
152.00
152.00
190.00
Mechanical work
HP
117.31
115.99
101.40
101.40
141.41
KW
87.52
86.53
75.64
75.64
105.49
%
69.83
69.04
66.71
66.71
74.43
Efficiency
Two of the three pumps were working to feed Amine re-boiler medium heater, so four pumps worked to serve two Amine re-boiler medium heater. Each circ.-pump (P-111 A/B) worked at 2211 and 2186 GPM, with 69% efficiency and P-211 A/B worked at 1911 GPM, with 66% efficiency. All pumps are operated close to design efficiency. Lean Amine Booster Pump : Table 3-13 : Performance of Lean Amine Booster Pump
DESCRIPTION
UNIT
225-P-101A
225-P-101B
1.05
1.05
1.00
137.00
137.00
125.00
specific gravity
Design
Temperature
F
suction pressure
psia
16.70
16.70
N/A
discharge pressure
psia
131.70
131.70
N/A
flow
GPM
225.00
225.00
1430.00
Total head
ft
115.00
115.00
244.00
Electric motor power
HP
70.00
70.00
122.00
Mechanical work
HP
15.43
15.43
90.05
Efficiency
%
22.04
22.04
73.81
The worst case was found at Amine booster pumps, the efficiency of P-101-A/B is only 22 %. The production process utilized two of the three pumps to support Lean amine charge pumps. Each of these booster pumps pumping out fluid at 225 GPM. The sum of fluid flow rate (450 GPM) is still far below the design flow rate for one pump. Higher efficiency could be achieved should the fluid flowing is handled by one pump only. 3.2.3 CONDENSATE STABILIZING SYSTEM A. DESCRIPTION Hydrocarbon liquid from inlet separator and LTS are sent to the stabilizer feed drum. Gas from the feed drum is sent under back pressure control to the low pressure fuel gas system.
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The hydrocarbon liquid from the feed drum is fed under level control to the top tray of the condensate stabilizer. The stabiliser reboiler is a kettle type shell and tube exchanger utilizing hot water from Medium Heater at operation. The condensate product from the stabilizer is sent via the HC condensate cooler bundle in the refrigerant condenser air cooled exchanger frame and a kettle type hydrocarbon condenstae cooler by propane refrigerant, gas blanketed, condensate storage tank. B. PERFORMANCE Main equipment of Condensate Stabilizing system are includes : Heat medium heater 257-H-101A/B, 257-H-201A/B; Stabilizer Re-boiler 235-E-101A/B, 235-E-201A/B; Condensate Cooler 235-E-102, 235-E-102 Heat Medium Heater : Table 3-14 : Performance of Heat Medium Heater 257-H-101A
DESIGN
0.12
0.10
T out, F
511.20
629.00
O2, %
13.90
3.00
Excess Air, %
179.07
15.27
, lb/hr
106,647.53
110,000.00
T in, F
310.00
316.60
T out, F
350.00
360.00
P in, Psi
N/A
200.00
P out, Psi
N/A
200.00
Heat absorption (LHV), MMBtu/hr
5.34
4.76
Heat absorption (HHV), MMBtu/hr
5.45
4.76
Efficiency (LHV), %
73.57
83.00
Efficiency (HHV), %
67.94
75.49
1,122.86
937.53
FUEL, Flow, MMSCFD FLUE GAS
HOT WATER
PERFORMANCE
CO2 EMISSION CO2 Emission from fuel gas, lb/hr
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Table 3-14 : Performance of Heat Medium Heater 257-H-201A
257-H-201B
DESIGN
FUEL, Flow, MMSCFD
0.15
0.14
0.17
T out, F
568.80
525.60
629.00
O2, %
8.50
10.20
3.00
Excess Air, %
62.20
86.38
15.27
, lb/hr
228,820.95
180,110.31
164,900.00
T in, F
300.00
300.00
316.6
T out, F
330.00
330.00
360
P in, Psi
N/A
225.00
227.5
P out, Psi
N/A
210.00
200
Heat absorption (LHV), MMBtu/hr
7.38
6.66
7.94
Heat absorption (HHV), MMBtu/hr
7.48
6.76
8.00
Efficiency (LHV), %
81.18
80.73
84.00
Efficiency (HHV), %
74.76
74.36
76.77
1,404.86
1,275.47
1,552.85
FLUE GAS
HOT WATER
PERFORMANCE
CO2 EMISSION CO2 Emission from fuel gas, lb/hr
The above table shows that H-101 A, H-201 A and H-201-B are operated close to design condition. The efficiency by using heat loss method are calculated based on the fuel gas heating value, flue gas composition and temperature measurement by using flue gas analyzer. Flue gas temperature is lower than design condition but the excess air is very high. Calculated Efficiency of 257-101-A is 73 % compare to design is 84 % and the efficiency of 257-201-A/B is around 81 % compare to design is 84 %. The lower efficiency is caused by higher excess air of the heater.
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Condensate Stabilizer Re boiler : Table 3-15 : Performance Condensate Stabilizer Re-boiler
235-E-101
235-E-201
180.00
200.00
DESIGN
HEAT MEDIUM SIDE (SHELL) Pressure, psig
200.00
Temp. inlet, F
350.00
335.00
350.00
Temp. outlet, F
295.00
300.00
310.00
Flowrate (Heat medium), Lb/hr
39,139.19
57,038.28
Temp Condensate to reboiler, F
278.00
278.00
298.00
Delta T LMTD
34.78
32.93
45.36
HEAT DUTY, Btu/hr
2,214,754
2,053,347
HEAT TRANSFER RATE, (BTU/Hr.Ft2.F)
39.14
38.32
n/a
Hydrocarbon Side
3,000,000 40.65
The above table shows that actual condition of heat duty of 235-E-201 and 235-E-101 is lower than design. The reboiler of 235-E-201 have capacity higher than 235-E-101 but the heat transfer rate are close to design. Condensate Cooler : Table 3-16 : Performance Condensate Cooler 235-E-102
235-E-202
DESIGN
Temp inlet, F
288.00
288
304.30
Temp outlet, F
106.60
106.5
120.00
Flowrate, GPM
101.89
193.4
287
Temp inlet, F
92.00
92
95.00
Temp outlet, F
136.00
136
139.90
Delta T LMTD
58.65
58.52
74.00
1,976,054
3,752,578
7,841,737
CONDENSATE
AIR COOLANT:
HEAT DUTY, Btu/hr
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HEAT TRANSFER RATE, BTU/HR.FT2.F
1.11
2.12
2.36
ELECTRIC CONSUMPTION **), KW
8.83
9.42
11.00
The above table shows that the condensate cooler have heat duty only 25% for 235E-102 and 48% for 235-E-202 refer to the design value. This caused by the flow rate of condensate, and LMTD. The flow rate for 235-E-102 is 35% and 235-E-202 is only 67% refer to the design. LMTD value for cooler 235-E-102 and 235-E-202 are 80% from LMTD design. This affect the value of heat load (Q) of coolers, because the heat load is straight forward with condensate flow rate and LMTD. The overall heat transfer rate (U) at actual condition is 1.11 BTU/(Hr/Ft2.F) for 235-E102 and 2.12 BTU/(Hr/Ft2.F for 235-E-202 compare to the design is 2.36 2 BTU/(Hr/Ft .F). 3.2.4 DEW POINT CONTROL AND REFRIGERATION SYSTEM A. DESCRIPTION The propane refrigerant gas from gas chiller via suction scrubber enter the 1st stage propane compressor. The propane refrigerant gas from the 1st compressor discharge and from the economizer goes to the propane compressor 2nd stage than the discharge of 2nd stage goes to the condenser cooler and enter to the accumulator. Propane refrigerant from the accumulator goes to the economizer (flushing). Propane gas from the economizer enter the suction of 2nd stage compressor and the propane refrigerant enter the gas chiller via propane subcooler. The design flowrate of the 1st stage propane compressor is 38,200 lbs/hr and the 2nd stage of propane compressor is 52,800 lbs/hr. There are 3 propane compressor driven by electric motor 1300 KW each and via refrigerant header supply refrigerant for 4 gas chillers (1 gas chiller for 1 train). At the actual condition only 2 compressor are in operation. B. PERFORMANCE Main equipment at Refrigeration system are includes propane condenser, propane compressor and gas chiller. Propane Condenser : Table – 3.17 : Performance of Propane Condenser 230-E-104 PROPANE :
DESIGN
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Pressure, psig
250
265
Temp inlet, F
140.00
180.00
Temp outlet, F
119.00
121.00
Flowrate, MMSCFD (gas)
30.00
32.90
Temp inlet, F
92.00
95.00
Temp outlet *), F
112.00
117.50
Delta T LMTD
27.50
26.30
HEAT DUTY, Btu/hr
19,151,470
25,387,806
ELECTRIC CONSUMPTION **), KW
17.67
22.00
HEAT TRANSFER RATE, BTU/HR.FT2.F
2.59
3.29
AIR COOLANT:
The above table shows that actual condition of heat duty of 230-E-104 is 75% compare to design. The heat duty impact on the power required for fan driver which is 80% electric consumption respectively. The U value (overall heat transfer rate) at actual condition is 2.59 BTU/(Hr/Ft2.F) and 3.29 BTU/(Hr/Ft2.F for the design value. Entirely, the performance of propane condenser is operated at good condition. Propane Compressor: Table – 3.18 : Performance of Propane Compressor UNITS
PROPANE FLOW ST. 1
DESIGN
K 101 A
30,669.25
25,861.64
(calculated)
(calculated)
42,446.24
35,792.51
(calculated)
(calculated)
24.50
24.00
24.00
ABL.DISCHARGE PRESS ST 1
101.00
100.00
100.00
ABSL DICHARGE PRESSURE ST. 2
265.00
260.00
260.00
TOTAL POWER REQUIRED
1,214.78
966.64
815.11
ACTUAL POWER
1,300.00
1,110.00
936.00
PROPANE FLOW ST. 2 ABSL SUCTION PRESSURE ST.1
COP
38,160.00
K 101 C
52,800.00
1.89
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The above table shows that the propane compressor operated at 70-80 % load. The calculated propane flow of stage-1 K-101 A and K-101 C are 30,669 lb/hr and 25,861 lb/hr with the actual power are 1110 KW and 936 KW . The design propane flow of stage-1 is 38,160 lb/hr with the power is 1,300 KW. It means that the propane compressor is still operated at normal conditions. The design COP of the propane compressor is 1.89. COP at actual condition can not be calculated accurately because no meter for propane flow. Gas Chiller: Table – 3.19 : Performance of gas chiller UNITS
DESIGN
GAS CHILLER (230-E102/201/302/402)
GAS INTAKE TEMP.AT EVAP.
DEG F
1.00
16.00
GAS OUTPUT TEMP.AT EVAP.
DEG F
(10.00)
5.00
SALES GAS FLOW
MMCFD
300.00
533.00
BBL/D
4,000.00
3,000.00
16.52
11.80
2,600.00
1,930.00
1.86
1.79
CONDENSATE FLOW HEAT RELEASE
MMBtu/hr
TOTAL POWER
KW
C.O.P
The above table shows the cooling load of gas chiller is 71 % load and two of propane compressor are operated to handle the refrigeration system. Performance of each gas chiller can not be calculated, because two propane compressors serve four gas chillers simultaneously. However total performance still can be calculated. The operating condition of four gas chiller almost similar (T gas inlet = 16 F , T out gas = 5 F). Total COP of gas chiller is 1.79. It’s still close to design condition. 3.2.5 GAS COMPRESSION A. DESCRIPTION The pressure of treated gas after Amine System and Refrigeration System is decrease lower than 1000 psig. To meet the pressure requirement of sales gas it needs to compress sales gas by using Residual Gas Compressor. There are 4 gas compressor 2 x 235 MMSCFD and 2 x 300 MMSCFD driven by gas turbine generator. At the actual condition only 3 GTC in operation and 1 GTC standby
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B. PERFORMANCE Main equipment at Gas Compression System are 242-K-101, 242-K-102, 242-K-301 and 242-K-401, Gas Compressor : Table – 3.20 : Performance of Gas Compressor UNITS
DESIGN
242-K-301
242-K-401
SALES GAS FLOW ( Q )
MMSCFD
235.00
206.00
206.00
SUCTION PRESSURE
PSIA
965.00
915.00
915.00
DISCHARGE PRESSURE
PSIA
1,295.00
1,130.00
1,115.00
FUEL CONSUMPTION
MMBtu
36.01
28.06
26.36
POWE REQUIRE (POLYTROPIC)
HP
4,537.09
2,835.13
2,651.33
ENERGY INTENSITY
Btu/HP
7,936.81
9,896.28
9,940.95
DESIGN SALES GAS FLOW ( Q )
MMSCFD
SUCTION PRESSURE
242-K-101
10,905.10
150.00
PSIA
955.00
910.00
DISCHARGE PRESSURE
PSIA
1,215.00
1,110.00
FUEL CONSUMPTION
MMBtu
40.92
20.19
POWE REQUIRE (POLYTROPIC)
HP
4,653.97
1,940.43
ENERGY INTENSITY
Btu/HP
8,792.49
10,406.28
242-K-201 OFF
The above table shows that the compressor are operated at 80 % load compare to design condition. The Energy Intensity (Btu/HP) of 242-K-101, 242-K-301 and 242-K-401 are higher compare to design value. This condition is caused by the lower operating load of compressors. To know the performance of compressor, it should be compare with design performance of gas turbine compressor (see table below).
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Gas Turbine : Table – 3.21 : Performance of Gas Turbine Compressor 29-Sep-07 242-KT-101 A
DESIGN
242-KT-201
242-KT-101 /201
TURBINE Fuel gas : flow, MMSCFD
0.59
OFF
1.02
Temperature, C
1,213
OFF
1,160
O2, %
14
OFF
14
Excess Air, %
191
OFF
185
Eff, %
19
OFF
25
Btu/HP
13,256
OFF
10,115
Power Required, KW
1,447
OFF
3,471
, HP
1,940
OFF
4,653
Flue gas :
B
COMPRESSOR
29-Sep-07 242-KT-301 A
DESIGN 242-KT-401
242-KT-301/ 401
TURBINE Fuel gas : flow, MMSCFD
0.73
0.70
1.05
Temperature, C
1,261
1,237
1,175
O2, %
14
14
14
Excess Air, %
168
174
174
Eff, %
23
23
27
Btu/HP
10,946
11,225
9,401
Power Required, KW
2,115
1,978
3,409
, HP
2,835
2,651
4,570
Flue gas :
B
COMPRESSOR
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In the daily operation, the gas turbines efficiency is around 23 %, these efficiency is less than the design condition (27%). Based on the design performance below, the performance of gas turbine at low load are close to design figure. DESIGN PERFORMANCE OF GTC K-301/401 POWER, HP BTU/KWH
5,000.00
4,000.00
3,000.00
2,000.00
1,000.00
9,400.00
10,000.00
11,000.00
12,500.00
17,000.00
DESIGN PERFORMANCE OF GTC K-101/201 POWER, HP BTU/KWH
5,000.00
4,000.00
3,000.00
2,000.00
1,000.00
10,100.00
10,700.00
11,600.00
13,200.0 0
17,000.00
3.2.6 GAS TURBINE GENERATOR A. DESCRIPTION Electrical power Generator driven by Gas turbine generator, with the gas supplied from HP (high pressure) fuel gas system. There are 2 GTGs each 1173 KW from Suban phase-1 and 3 GTGs each 5820 KW from Suban phase-2. The Generator specification are 5820 KW of power, 6600 volt, freq 50 Hz, cos Q 0.85. The large motors (lean amine charge pump, Amne reboiler HM Pump, propane compressor) are supplied by 6600 volt and the other motors using 400 volts. B. PERFORMANCE The main equipment of gas turbine generator are 247-GTG-101A/B and 247GTG-201A/B/C The performance of GTG are as follow : Table – 3.22 : Performance of GTG 29-Sep-07 247-GT-201A
247-GT201B
DESIGN 247-GT201C
247-GT-201A
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TURBINE Fuel gas : flow, MMSCFD
0.90
0.9
0.90
1.62
Temperature, F
916
921
925
946
O2, %
16
16
16
15
Excess Air, %
312
309
308
243
Turbine Eff, %
18.04
18.04
18.01
30
Btu/kwh
16,925
16,926
16,950
11,336
Flow, lb/hr
5,611
5,611
5,611
4,446
Power Output, KW
2,146
2,102
2,178
5,821
PF
0.83
0.83
0.84
Voltage, V
6,600
6,600
6,600
6,600
Frequency, Hz
50
50
50
50
Flue gas :
CO2 emission : GENERATOR 0.83
GTGs are operated less than 40 % load each, total load is around 6,426 KW. This load actually can be handle by two GTGs with 55 % load each. If any disturbance occurs, the load shading system will shut off un-priority load, so system black out can be avoided. The low load of GTG caused low efficiency of gas turbine. The stack temperature of GTG are close to design condition but the calculated efficiency is only 18 % compare to design which is 30 %. The decreasing efficiency is caused by lower operating load which will increased radiation and convection loss. Compare to the design performance of gas turbine generator (table below) , the performance GTG at low load are still in good condition Table – 3.23 : Design Performance of GTG DESIGN POWER BTU/KWH
PERFORMANCE OF GTG 5,800 11,340
5,000 11,800
4,000 12,600
3,000 14,300
2,000 17,200
1,000 25,000
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3.2.7 AIR COMPRESSOR A. DESCRIPTION Instrument and utility air are supplied by the 1x340 scfm and 1x140 scfm screw type compressor. The compressed air is filtered and then dried in heatless adsorption type dries which are on automatic regeneration cycles. The instrument air compressor packages are provided with local electronic control panels. The instrument air receiver is normally operated between 110 and 120 psig. B. PERFORMANCE There are four compressors Atlas Copco GA 37 x 2 and GA 75 x 2 with design capacity is 960 SCFM, the duty of each equipment are as follows, The performance of air compressor are as follows : Table 3-24 : Performance of Air Compressor 251-A-101A (ATLAS COPCO GA 75)
DESIGN
ACTUAL
POWER
72.60
45.93
COMPRESS AIR FLOW
340.00
266.66
0.20
0.20
ACTUAL PERFORMANCE
251-A-101 B (ATLAS COPCO GA 37) DESIGN
ACTUAL
POWER
44.00
28.27
COMPRESS AIR FLOW
140.00
129.90
0.33
0.25
ACTUAL PERFORMANCE
The above table shows that the compressor is operated at low load. Actual power of 251-A-101 A is 45.93 KW compare to design 72.6 KW and 251-A-101 B is 28.27 KW compare to design 44 KW. Actual performance of air compressor calculated by : (Actual power / Qs x ((Pd/Ps)^0.2857 – 1))
Note : Qs = air flow
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3.2.8 ELECTRICAL MAP SUBAN GAS PLANT Electrical map is derived from single line diagram, and intend to get a closer and clear point of view to one that need brief description on power consumption at each process. This map is made simple as possible so, it doesn't show how the electric system is distributed. Emphasize is given to voltage, and power required for each equipment. Note that the power mentioned below is the power in normal design condition. A. Inlet Gas System
400 V 215-EM-301/401/A/B 1-2 Inlet cooler fan 22 KW x8
B. Amine System 6.6 KV
225-P-102A/B/C Lean Amine Charge pump A/B/C
225-P-111A/B/C Amine reboiler H/M circ pump A/B/C
1130 HP x3
225-P-211A/B/C Amine reboiler H/M circ pump A/B/C
185 HP x3
185 HP x3
400 V 225-P-102A/B/C Lean Amine booster pump A/B/C
225-PM-103A/B Regenerator reflux pump A/B
225-PM-203A/B Regenerator reflux pump A/B
112 HP x3
3.73 HP x2
3.73 HP x2
225-EM-103A/B/C/D Lean Amine cooler fan 19 KW x4
225-EM-203A/B/C/D 225-EM-105/205/305/405 A Lean Amine cooler fan Treated gas cooler fan 19 KW x4
225-EM-101/201 A/B/C/D 225-PM-105 Regenerator reflux condenser fan Amine transfer pump 11 KW x8
14.7 HP
19 KW x4
225-EM-105/205/305/405 B Treated gas cooler fan 19 KW x4
225-PM-104 Amine sump pump 14.7 HP
C. Dehydration system 400 V 229-PM-302/402/A/B Glycol Injection pump 26.8 HP
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D. Propane Compressor System 6.6 KV
230-KM-101 A/B/C Propane compressor A/B/C 1306 KW x3
400 V
230-EM-104 A/B/C/D 1-2 Propane condenser fan A-D
230-K-101-EM1-6 L.O. cooler fan propane compr. A/B/C
230-K-101-PM 1-3 L.O. pump for propane compr. A/B/C
22 KW x8
7.15 KW x6
6.7 HP x3
E. Depropanizer and Condensate Stabilization System 400 V
230-EM-107A/B Depropaniser overhead condenser fan
230-PM-102 Depropaniser reflux pump
7.5 KW x2
1.7 HP
230-H-106 Depropaniser reboiler heater
235-EM-202A/B Condensate cooler fan
106 HP
11 KW x2
230-PM-101 Depropaniser overhead feed pump 7.1 HP
235-KM-201 235-PM-102D/E Vapoor recovery compr. Condensate shipping pump 29.5 HP
40 HP x2
F. Residue Gas Compressor System 400 V
242-EM-301/401 A-D Residue gas compr. After cooler 15 KW x8
G. Air Compressor, and Utility
400 V
251-A-201 N2 generation 30 KW
252-PM-101 C-G 251-KM-201 A/B 252-PM-104 A/B Air compressor A/B Well water lift pump Portable water pump 5.36 HP x5 120 HP x2 7.4 HP x2
252-PM-105 A/B Amine makeup water pump A/B 15 HP x2
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H. Flare, and Water handling 400 V 248-P-101/201 A/B Flare KO drum A
258-PM-202 A/B Produced water injection pump A/B
3 HP x8
60 HP x2
3.3
257-PM-201 A/B/C Heat medium circ. pump A/B/C 49.5 HP x3
FINDINGS AND RECOMENDATION
1. Instrumentation and Metering Based on the site survey founded that many metering and instrument are not work properly. Findings and recommendations of metering and instrumentation at Suban Gas Plant are as follows :
Equipments 1.
2
3
4
Amine Reb HM Heater
H-M Heater
Gas Turbine Generator
Gas Turbine Compressor
Findings
There are inaccurate temperature indicator of circulation Hot Water
Combustion analyzer in each HM Heater not work properly
Recommendations
the oxygen analyzer should be repaired
Need to calibrate meter of hot water temperature indicator
No Oxygen analyzer
The calculated efficiency of HM Heater from direct method difference with heat loss method. This discrepancy maybe caused by lack of accuracy of Temperature indicator and hot water circulation flow meter.
Need to install oxygen analyzer in order to monitor the performance of this equipment
Need to calibrate temperature indicator and hot water circulation flow meter
Need to install fuel gas flow meter and link to DCS
Need to calibrate fuel flow meter and
There is no flow meter of fuel gas in each GTG.
Some indicator/sensor of GTGs have no link to DCS in CCR
lack of meter
accuracy fuel
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link to DCS 5
Propane compressor
No power record for propane compressor
Need to implement continues record for propane compressor to evaluate COP
6
Chiller
Temperature inlet and outlet gas chiller are inaccurate
need to install temperature indicator inlet and outlet gas chiller for performance evaluation and link to DCS
7
Air compressor
No power meter for air compressor
need to install meter of air compressor for performance evaluation and link to DCS
8
Pumps
No power meter for lean amine booster pump
need to install meter of lean amine booster pump for performance evaluation and link to DCS
9
Heat Exchanger
No temperature and pressure indicator at gas-gas exchanger
Temperature indicator of steam at amine Re-boiler are not accurate
Need to install temperature indicator at gas-gas exchanger for performance monitoring Need to calibrate the steam temperature indicators at amine re-boiler
10
Amine system
Temperature indicator between inlet and outlet are not accurate
Recalibration temperature indicator
11
Electric Distribution
No continue recording for electrical distribution
Need to record electrical distribution (6000 V line) at daily records
of
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2. Heater Based on the calculation bellows are the efficiency, heat absorb and CO2 emission of fired heater at Suban Gas Plant
EFFICIENCY
HEAT DUTY
CO2 EMISSION
%
MMBtu/hr
Lb/hr
DESIGN
89.11
57.98
10,609.42
225-H-111
85.80
31.81
5,730.36
225-H-211
84.87
28.70
5,203.54
DESIGN 257 H-101A/B
84.00
4.37
712.53
257-H-101A
73.60
5.35
1,122.86
257-H-101B
OFF
OFF
OFF
DESIGN 257 H-201A/B
84.00
7.94
1,552.85
257-H-201A
81.18
7.38
1,404.86
257-H-201B
80.73
6.66
1,275.47
AMINE REB H-M HEATER
HEAT MEDIUM HEATER
Finding : The above tables shows that :
The heat duty of Amine H-M Heater is only 50 % and 44 % load compare to design condition. The Gas Plant are operated at 517 MMSCFD of sales gas or 74 % load compare to design condition. This condition means that the design of fired heater is too large.
Amine H-M Heater is operated at high excess air (44 % and 71 % ) compare to the design figure which is 15 % excess air. This excess air will impact lower efficiency of H-M Heater
HM Heater is operated at high excess air (62 %, 86 % and 179 % ) compare to the design figure which is 15 % excess air. This excess air will impact lower efficiency of Heater (Calculated Efficiency from heat loss method will be around 70 % compare to design is 84 %)
Recommendation :
Design Amine H-M Heater is too large, so the heater can be handle for revamping until 125 % Amine Capacity.
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Page 55 of 109
Amine H-M Heater is the main energy consuming equipment in the amine system, so its performance should be monitored daily. Hence, it needs temperature and O2 meters at flue gas line to support the monitoring activity.
Amine H-M Heater should be operated close to the design excess air (15%) to achieve better efficiency,
HM Heater should be operated close to the design excess air (15%) to achieve better efficiency
5. Gas turbine generator Based on the calculation, bellows are the efficiency, heat rate, BHP and CO2 emission of GTG at Suban Gas Plant:
GAS TURBINE GENERATOR
EFFICIENCY
HEAT RATE
BHP
CO2 EMISSION
%
BTU/KWH
KW
Lb/hr
DESIGN
30.43
11,336.00
6,063.54
9,803.22
247-GT-201A
18.04
16,924.65
2,235.42
5,610.65
247-GT-201B
18.06
16,908.92
2,189.58
5,610.65
247-GT-201C
18.01
16,949.55
2,268.75
5,610.65
Finding :
Three GTGs load are low in daily operation ( less then 40%),.the average efficiency is around 18 % (design = 30 %)
Heat rate of three GTGs are around 16.9 MBtu/KWH compare to design 11.3 MBtu/KWH
Recommendation :
To achieve better efficiency, GTGs should be operated at more then 50 % load (two GTGs in operation)
Load shading should be operated properly to sustain two GTGs in operation
6. Gas turbine Compressor Power require and energy intensity of residue gas compressor are as follows :
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Page 56 of 109
SALES GAS FLOW, MMSCFD
POWE REQUIRE, KW
ENERGY INTENSITY, KW
DESIGN 242-K-301
235.00
4,537.09
7,936.81
242-K-301
206.00
2,835.13
9,896.28
242-K-401
206.00
2,651.33
9,940.95
DESIGN 242-K-101 242-K-101
300.00 150.00
4,653.97 1,940.43
8,792.49 10,406.28
OFF
OFF
OFF
242-K-102
Turbine efficiency, heat rate and CO2 emission are as follows :
TURBINE
Turbine Eff,
Heat Rate
CO2 emission :
%
Btu/BHP
lb/hr
DESIGN 242-KT-301
29.13
7,878.86
5,341.69
242-KT-301
23.53
9,746.77
1,838.04
242-KT-401
23.35
9,942.20
1,753.20
DESIGN 242-KT-101
25.89
8,793.54
6,070.11
242-KT-101
21.78
10,737.29
1,385.60
242-KT-102
OFF
OFF
OFF
Finding :
Max capacity of KT-401 and KT-301 are 235 MMSCFD each, with suction press 950 psi and discharge 1280 psi
Max capacity of KT-201 and KT-101 are 300 MMSCFD each, with suction press 950 psi and discharge 1200 psi
Actual turbine efficiency of KT-401 and KT-301 is around 23 % and KT-101 is 22 % compare to design efficiency of KT-401 and KT-301 are 29 % and KT-101 is 26 %
Based on the design flow rate, 3 GTCs can handle 770 MMSCF
7. Propane Compressor Performance of propane compressor are as follows :
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POWER REQUIRED, KW
DESIGN
Page 57 of 109
ACTUAL POWER, KW
COP
1,214.78
1,300.00
1.89
230-K 101 A
966.64
1,110.00
1.78
230- K 101 C
815.11
936.00
1.78
Finding :
Inlet flow of refrigerant vapor to propane compressors come from one header, so difficult to evaluate COP each compressor.
Design COP of propane compressor is 1.89, calculated COP at actual condition (based on heat absorb) is around 1.78
8. Gas Chiller Performance of gas chiller are asfollows : GAS CHILLER
UNITS
DESIGN
EVAPORATOR (102,201,302,402)
GAS INTAKE TEMP.AT EVAP.
DEG F
1.00
16.00
GAS OUTPUT TEMP.AT EVAP.
DEG F
(10.00)
5.00
SALES GAS FLOW
MMCFD
300.00
533.00
BBL/D
4,000.00
3,000.00
CONDENSATE FLOW HEAT RELEASE
MMBtu/hr
TOTAL POWER
KW
C.O.P
16.52
11.80
2,600.00
1,930.00
1.86
1.79
Finding :
Inlet flow of refrigerant to gas chiller come from one header, so difficult to evaluate COP for each gas chiller
Heat duty of four gas chiller is 11.8 MMBTU/hr compare to design is 16.52 MMBTU/hr. The motor power of propane compressor is 2046 kW
Design COP of gas chiller is 1.86, calculated COP at actual condition (based on heat release) is around 1.79
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Page 58 of 109
9. Pump Finding : Calculated efficiency of pumps are as follows; PUMPS
Flow, GPM Actual
Efficiency, %
Design
Actual
Design
Amine Charge Pump 225-P-102A
265.00
225-P-102B
265.00
1165.00
39.54
76.67
39.54
Amine Booster Pump 225-P-101A
225.00
225-P-101B
225.00
1430.00
22.04
73.81
22.04
Amine Reboiler H/M Circulation Pump 225-P-111A
2211.00
3044.00
69.83
225-P-111B
2186.00
69.04
225-P-211A
1911.00
66.71
225-P-211B
1911.00
66.71
74.43
Amine charge pumps and Amine booster pumps were running in low efficiency. This is due to very low of fluid rate they handled. Should two split of flow that flowing through “Amine booster pumps is merged together to flow through one pump only(530 GPM), its total flow still far below the rate of design (1165 GPM). The similar case was found at Amine booster pumps. Two pumps were running to handle 225 GPM rate each. Recommendation : Higher efficiency could be achieved should the fluid flowing is handled by one pump only (If total rate of flow not exceed flow rate at design). 10. Cooler Findings : Calculated of coolers are as below: No .
COOLER
HEAT DUTY
HEAT TRANSFER RATE
ELECTRIC/ HEAT DUTY
(MMBTU/HR)
(BTU/HR.FT2.oF)
(%)
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1.
2.
3.
4.
5.
6.
Page 59 of 109
Inlet Gas Cooler 215-E-101
28.37
4.46
0.63%
215-E-201
28.37
4.46
0.63%
215-E-301
43.04
3.08
0.42%
215-E-401
43.04
3.08
0.42%
225-E-105
4.62
3.91
4.19%
225-E-205
3.87
2.95
4.90%
225-E-305
5.35
1.89
3.77%
225-E-405
OFF
OFF
OFF
225-E-101
9.26
1.94
0.65%
225-E-201
13.23
2.68
1.03%
225-E-103
16.78
1.60
0.72%
225-E-203
16.25
1.53
0.74%
235-E-102
1.98
1.11
1.53%
235-E-202
3.75
2.12
0.86%
Propane Cooler 230-E-104
19.15
2.59
0.31%
Treated Gas Cooler
Regenerator Reflux Condenser
Lean Amine Cooler
Condensate Cooler
Power required to drive motors of fan coolers are below 1% due to their heat duties. This condition indicate that the power consumption of these coolers are in good condition except Treated gas cooler and Condensate cooler. Recommendations : Need to check again the performance of Treated gas cooler and Condensate cooler, especially motor driver of fan coolers. 11. Heat Exchanger Findings : Calculated of Heat Exchangers are as listed below: No.
1.
HEAT EXCHANGER
Stabilizer Reboiler
HEAT DUTY
HEAT TRANSFER RATE
(MMBTU/HR)
(BTU/HR.FT2.oF)
DIRTY FACTOR ACTUAL
DESIGN
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2. 3.
4.
Page 60 of 109
235-E-101
2.21
39.14
0.0009
0.0010
235-E-201
3.02
48.13
0.0034
0.0010
De-C3 Reboiler 230-E106 Rich/Lean Amine Exch.
0.18
N/A
N/A
N/A
225-E-104A/B
16.40
N/A
N/A
N/A
225-E-204A/B
20.96
N/A
N/A
N/A
Gas-Gas Exch. 230-E307
14.00
157.31
0.0023
0.0020
The performance of heat exchangers still in good condition, except for Stabilizer Reboiler 235-E-201, because the dirty factor more than design specification. 12. Energy Losses, Potential Saving and Emission Reduction Potential Based on heat balance calculation, energy losses from high temperature flue gas at Suban is coming from Stack of Thermal Oxidizer, GTG and GTC.
STACK LOSS, Btu/hr
TEMP, Deg F
Thermal Oxidizer 225-H-102
35,495,414
932
225-H-202
8,303,983
2,012
247-GT-201A
33,163,974
916
247-GT-201B
29,310,275
921
247-GT-201C
29,397,944
925
242-K-101
21,555,786
1,213
242-K-301
22,755,271
1,261
242-K-401
21,806,787
1,237
201,789,433
1,177
GTG
GTC
TOTAL
a. Energy Losses : Total losses from flue gas is around 201 MMBtu/hr with average temperature 1,177 deg F. Actually, by utilizing economizer with stack temperature around 500 deg F, this Flue gas losses can be used to generate saturated steam about 120,000 lb/hr.
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Page 61 of 109
b. Potential Saving : Based on the evaluation, shows that the potential saving are coming from :
Optimize operation of GTG will increase efficiency from 18 % to 23 % that will reduced HP Fuel consumption about 0.14 MMSCFD
Optimize operation of all heater will increase efficiency around 5 %, that will reduced LP fuel consumption about 0.1 MMSCFD
Utilized flare gas that will reduced fuel consumption about 0.8 MMSCFD
Energy Conservation Opportunities :
Optimize operation of GTGs can be implemented by load shading
Optimize operation of Heater and utilized flare gas can be implemented by installing booster compressor to compress gas up to 180 psig. This fuel gas can be used for Gas turbine and in turn it will reduce HP Fuel consumption. The simple calculation are as follows :
Fired Heater-saving, MMSCFD
0.10
, US $/Year
123,750.00
Flare Gas-saving, MMSCFD
0.80
, US $/Year
990,000.00 Total, MMSCFD
0.90
, US $/Year
1,113,750.00
*Cost to install the system for recovery gas which includes : gas compressor, KO Drum, Instrumentations , US $
2,400,000.00
Operation and Maintenance Cost , US $/year
120,000.00
Net income , US $/Year
993,750.00
Estimated payback period to install the system , Years
2.42
* = refer to Beak Pacifik Report - Energy Audit at Cilacap Refinery Complex (Beak Pacific Inc. , Vancouver, Canada)
c. Emission Reduction Potentials CO2 emission at suban gas plant is 127,901 lb/hr. its come from combustion of fuel gas at flare gas, heater, GTC and GTG.
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Page 62 of 109
CO2 reduction, lb/hr Optimized operation of GTG
642
Optimized operation of Heater
824
utilized flare gas
7,394 Total
8860
Optimised operation and utilized flare gas will reduce CO2 emission , %
7%
13. Reporting system Findings :
Existing daily report just only for production activity, it does not cover the data for plant performance evaluation purposes
No data acquisition and evaluation based on daily log sheet .
Important data for plant performance not covered in daily log sheet
Recommendation :
Daily reporting must covers production activity and plant performance indicator
Regulars summary of log sheet regarding plant performance should be evaluate.
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Page 63 of 109
IV. ENERGY ASSESSMENT CENTRAL GAS PLANT
AT
GRISSIK
4.1. GENERAL PLANT OPERATION AND PERFORMANCE 4.1.1. GENERAL PLANT OPERATION OF GRISSIK GAS PLANT The Central Gas Processing – Grissik plant was designed firstly for processing gas from four field in the Corridor Block, South Sumatra: Dayung/Sumpal and GLT (Gelam/Letang/Tengah) field. The quality gas from Dayung field has high CO2 content (31 %) and the gas quality from GLT has high condensate content. The source of inlet gas to be processed in CGP has changed after the Suban Gas Plant was operated. Partly of Suban Gas sales line also was processed in CGP if the specification of Suban Gas Sales was nearly out of specification, especially on the CO2 content. So, the mixed gas from Suban plant and CGP plant will meet specification at the gas sales pipeline. The simple process flow of CGP-Grissik Plant is shown with block diagram in figure 1.1 below: FlareGas T
11
T
1
T
2A
Gas/Liquid Separation
Dayung Gas Gathering Station
2B
T Gas Pretreatment
Permeate Gas
Acid Gas
5
6
Suban Gas Sales bypass
7
T
4
T Amine System
GasDehydrationSystem T
T
GelamGas
T
GasSales to pipeline
Propane Chiller
8
Gelam Liquid Gelam Gas/Liq GatheringStation
9
Suban Gas Sales toprocessedin CGP 3
T
10
Condensate Stabilization Condensateproduct to Bentayan & C3 Recovery
Figure 4.1 Gas Processed Block Diagram of CGP plant The flow diagram of CGP Grissik plant that obtained from basic design and field survey can be described below:
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Table 4.1. Flow Diagram (based on Design) Unit Temp (deg F) Pressure (psig) Flow, Gas (MMSCFD) Flow, Cond. (BBL/D) TOT_FLOW(MMSCFD)
1
3
2B
Stream 5 6
4
7
8
9
10
11
GlmLiq. to Dy&Sum Glm Dyg/Smp Codensat Dy&Sum Dy&Sum Dy&Sum Dy&Sum Dyg/Sum GlmGas AcidGas FlareGas GlmGas GlmGas GlmGas GlmGas Stabilizer Gas Condensate Gas e prod. Gas Gas Gas#1 Gas #2 Gas
87
87
53
1000 1000 176 310 129.46 0 0 0 520.2 439.46
ORBBL/D
2A
520.2
100
58
1121 1133 1099 1133 1099 9 302.2 129.46 114.02 129.46 114.02 70.22 0 0 0 0 0 0
120
11 1093 1125 1094 1087 1119 575 46.5 197.56 114.38 0 197.06 114.1 0 0 0 0 1745 0 777.83 0
75 0.16 0
302.2 129.46
46.5
1745
0.16
10
11
84
99
84
99
357.5
99
120
120
70.22
120
50
311.94
777.83
132
130
311.16
Table 4.2. Flow Diagram (Survey on Oct. 02, 2007)
Unit Temp (deg F) Pressure (psig) Flow, Gas (MMSCFD) Flow, Cond. (BBL/D) TOT_FLOW(MMSCFD) OR BBL/Dfor Liquid
1
3
2A
2B
Stream 5 6
4
7
GlmLiq. to Dy&Sum Dy&Sum Dy&Sum Dy&Sum DSS*) Glm Gas AcidGas GlmGas Glm Gas Sub Gas Stablzr Gas Gas Gas Gas Gas
87
87
84
138
1105 1011 142 1001 0 53.2 47.1 53.2 0 0 866.77 0 100.3035
866.77 100.3
84
123
84
87
109 143.15 120
8
GlmGas
Glm Cond.
120
37
9
Bypass DSSGas GlmGas Cod. prod. FlareGas Sub
94.5
93.1
90
80
1001 1023 47.1 46.7 0 0
1001 1000 47.1 101.6 0 0
23 2.57 0
993 203 12.1 993 1000 1000 998 20.6 132.85 41.95 0 434.68 146.46 39.39 0 0 0 829.95 0 0 0 1296 0
205 5.75 0
47.1
195.4
2.57
20.6
5.75
174.8
829.95
620.53
1324
*) DSS : Dayung/Sumpal & Suban
Based on overall process, the processing load of CGP plant during field survey activity is 54.6% of capacity design. This condition is caused by shut down condition for repairing of the Amine Regenerator 25-C-202. 4.1.2. GENERAL PLANT PERFORMANCE OF GRISSIK CENTRAL GAS PLANT The HP fuel gas supply for the plant is obtained from the Back-up sales gas line and Suban taping gas line via the pressure control valve. Gas heated by steam, under back pressure control, goes to the high pressure fuel gas scrubber which is operated at about 260 psig. The high pressure fuel gas supplies fuel the gas turbine and partly sent to Bentayan field. The LP fuel gas from the stabilizer feed drum and stabilizer overhead is supplied for TEG regeneration heater, gas pretreatment heater, fuel gas for WHB incenerator and flare purge gas, flare stack pilot, tank blanket. The HP fuel gas is supplied to GTG and to the LP fuel gas, when the LP gas demand exceeds the available LP fuel gas supply. CGP Grissik plant used three (3) type of energy for the process, utility and offsites facilities. The types of energy that used are : LP Fuel gas, steam from WHB and electricity from GTG. Based on 2 October 2007, the amount of fuel gas coming from scrubber is 5.910 MMSCFD. The distribution of fuel gas as shown in table below;
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Table 4.3 : Fuel gas distribution
1 Fuel Gas to Flare C
1.460
46-B-101
D
1.550
46-B-201
D
-
D
1.550
41-H-101
C
0.023
41-H-201
C
0.023
41-H-301
C
-
C
0.045
21-H-101
C
0.161
21-H-201
C
-
2 Fuel Gas to WHB
3 Fuel gas to Heater
4 Fuel gas to Regen Heater
0.161 5 Fuel gas to GTG 47-GTG-101A
C
0.70
47-GTG-101B
C
0.78
47-GTG-101C
C
-
D
1.48
D
1.560
6 Fuel gas to Bentayan
There are two type of fuel gas used, LP Fuel gas which is consumed by fired heater and HP Fuel gas which is consumed by GTG. The heating value of LP Fuel gas is around 1,060 Btu/SCF and HP Fuel is around 1,484 Btu/SCF Based on heat balance calculation in WHB and GTG, the energy picture based on 2 October 2007 which includes total energy input/heat released, heat absorbed, heat loss and CO2 emission as shown in table below,
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Table 4-4 : The energy picture based on 2 October 2007 HEAT RELEASE, Btu/hr
HEAT ABSORB, Btu/hr
STACK LOSS, Btu/hr
TEMP, Deg F
CO2 Emission, lb/hr
FLARE 90,840,020
0
84,736,763
1,562
12,421
21-H-101
8,473,864
5,794,116
2,487,229
430
1,377
21-H-201
0
0
0
0
0
41-H-101
1,196,695
922,279
256,466
430
191
41-H-201
1,196,695
922,279
256,466
430
191
41-H-301
0
0
0
0
0
46-B-101
165,049,729
120,492,608
41,432,959
376
158,802
46-B-201
0
0
0
0
0
47-GTG-101A
37,103,706
7,084,939
19,478,242
949
4,569
47-GTG-101B
40,880,730
7,415,749
18,133,682
967
5,034
47-GTG-101C
0
0
0
0
0
344,741,441
142,631,970
166,781,807
468
182,585
HEATER Regen Gas Heater
Glycol Heater
WHB
GTG
TOTAL
Plant Performance : The plant performance at 2 October 2007 are as follows : Table 4-5 : Plant Performance of Grissik Central Gas Plant PRODUCTION RATE Sales Gas = =
186.50 MMSCFD 31,083.33 BOE
Condensate =
1,234.00 BOE
Total Prod =>
32,317.33 BOE
ENERGY CONSUME Excluding Flare Including Flare
256,621,725.71 Btu/hr 347,461,746.16 Btu/hr
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ENERGY INTENSITY Excluding Flare Including Flare
Page 67 of 109
7,940.68 Btu/BOE 10,751.56 Btu/BOE
Total heat input to WHB, GTG,Regeneration Gas Heater and Glycol Heater is 253,901,420 Btu/hr and total heat released including flare gas is 344,741,441 Btu/hr. The production rate is 32,317.33 BOE which include 186.5 MMSCFD sales gas and 1,234 Barrel of condensate, means the energy consumed to produce one BOE (energy intensity) is 7,940.68 BTU/BOE (Excluding flare) and 10,751.56 BTU/BOE Including flare).
4.2. PERFORMANCE EVALUATION EACH SYSTEM 4.2.1. GAS PRETREATMENT & MEMBRANE SYSTEM A. DESCRIPTION The Gas Pre-Treatment Unit has been designed to operate at 2 x 50% each train with a total gas throughput capacity of 230 MMSCFD and designed to remove heavy hydrocarbons (C6+) from 380 ppm to 39 ppm. The overall process works on the principles of Adsorption, Regeneration and, Cooling and, is commonly referred to a Thermal Swing Adsorption (TSA) process. Each train has 4 Adsorber Towers. Under normal operation each train has 2 Adsorber towers in operation mode,one Adsorber Towers in Regeneration mode and one Adsorber Towers in cooling mode. The pretreatment consists of the following four steps process, i.e :
Coalescing filter for the removal of aerosols and particulates;
Heater to ensure the gas is above the dewpoint temperature;
Guard bed for the removal of heavy hydrocarbons and glycol;
Polishing filter
The Dayung gas from inlet separator is sent to the membrane unit to remove CO2, lowering the CO2 content of the gas from about 30.5 mole% to less than 15.0%. The Membrane CO2 separation unit was designed to process the Dayung gas to reduce the CO2 content of the gas from 31% to 15%. The remainder of the CO2 in the Dayung gas is then removed in the Amine-treating Unit, allowing the gas to meet the sales gas pipeline specification for CO2, which has a minimum value of 5%. As the Dayung gas flows through the semipermeable polimide membranes, approximately 63% of the CO2, 60% of the H2S, and 8% of the Methane is separated into the permeate gas stream. The permeate Gas, consisting of about 80% CO2 and 20% Methane, is sent to the Waste Heat Boilers as fuel gas.
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B. PERFORMANCE The main equipment at Gas Pretreatment (TSA) system are Regenerator Gas Heater and Regen Gas/Gas Exchanger The performance of main equipment are as follows : Table 4-6 : Performance of Performance of Regenerator Gas Heater : 2-Oct-07 21-H-101
DESIGN
21-H-201
21-H-101/201
1 FUEL, Flow, MMSCFD
0.16
OFF
0.31
T out, F
430.00 (Estimated)
OFF
430.40
O2, %
14.00 (Estimated)
OFF
14.00
Excess Air, %
185.64
OFF
185.64
Heat absorption (LHV), MMBtu/hr
5.75
OFF
11.06
Heat absorption (HHV), MMBtu/hr
5.80
OFF
11.16
Efficiency (LHV), %
74.65
OFF
74.62
Efficiency (HHV), %
68.40
OFF
68.38
1,376.93
OFF
2,651.23
2 FLUE GAS
3 PERFORMANCE
4 CO2 EMISSION CO2 Emission from fuel gas, lb/hr
Regen gas heater is operated at 60% load compare to design condition and the fuel consump is 0.16 MMSCFD The stack temperature and oxygen content are estimated close to design condition with the efficiency is 74.65 %
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Table 4-7 : Performance of Regen Gas/Gas Exchanger (21-E-101/201)
21-E-101
21-E-201
DESIGN
Gas to Membrane (Shell side) Pressure, psig
1097
OFF
1153
Temp inlet, F
85.00
OFF
85.78
Temp outlet, F
100.00
OFF
110.40
Flowrate of Gas, MMSCFD
26.00
OFF
215.07
Temp inlet, F
230.00
OFF
309.90
Temp outlet, F
109.00
OFF
95.00
Delta T LMTD
62.74
OFF
61.89
HEAT DUTY, Btu/hr
475,664
OFF
7,497,708
HEAT TRANSFER RATE, BTU/(Hr/Ft2.F)
3.12
OFF
6.26
Hot Gas (Regen Gas)
Table 4-8 : Performance of Cooler Gas/Gas Exchanger (21-E-102/202) 21-E-102
21-E-202
DESIGN
Regen Heater Gas/Hot Gas (Shell side) Pressure, psig
1097
OFF
1155
Temp inlet, F
400.00
OFF
541.60
Temp outlet, F
230.00
OFF
309.90
Flowrate of Gas, MMSCFD
20.00
OFF
25.93
Temp inlet, F
102.00
OFF
85.90
Temp outlet, F
120.00
OFF
335.60
Delta T, LMTD
194.18
OFF
212.40
HEAT DUTY, Btu/hr
4,674,675
OFF
8,267,466.11
Cold Gas (Regen Gas)
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HEAT TRANSFER RATE, BTU/(Hr/Ft2.F)
44.17
Page 70 of 109
OFF
55.43
The above table shows that the heat duty operated only about 0.475 MMBTU/hr for E101 and 4.67 MMBTU/hr for E-102, although the design heat duty is 7.5 MMBTU/hr for E-101 and 8.26 MMBTU/hr for E-102. This heat duty value produce capacity only about 6.34 % for E-101 and 56.54 % for E-102 compare to design capacity. This condition caused by the feed gas to TSA unit only 26 MMSCFD (110,283 lb/hr) for adsorption and 20 MMCSFD (87,483 lb/hr) for cooling condition compare to the design capacity for gas process adsorption is 115 MMSCFD (20% capacity). The different between design and operation are the LMTD value. Actual LMTD is 62.74 oF for E-101 and 44.17 oF for E-102 compare to design is 61.9 F for E-101 and 55.43 oF for E-102. The performance of heat exchanger can be evaluated from the value of overall heat transfer rate (U). The U at operating condition give value about 3.12 BTU/(Hr/Ft2.F) for 21-E-101 and 44.17 BTU/(Hr/Ft2.F for 21-E-102, while the design value is 6.26 BTU/(Hr/Ft2.F) for 21-E-101 and 55.43 BTU/(Hr/Ft2.F) for 21-E-102. 4.2.2. AMINE SYSTEM A. DESCRIPTION The gas treating process consists of three identical amine contactors, two normally treating about 114 MMSCFD of Dayung gas each (referred design base) and the third treating about 129 MMSCFD of Gelam, Letang, Tengah (GLT) gas. The amine units are designed to produce treated gas containing less than 2% CO2 and 4 ppmV H2S consequently the bypasses allow the sales gas still to meet its specification of 5% CO2 and 8 ppmV of H2S. Amine unit feed gas stream enters the bottom of an amine contactor where it is counter-currently contacted with lean 50 wt% UCARSOL solution with main composition is MDEA solution. CO2 and H2S are absorbed by the lean amine and the treated gas exits the top of the tower. The amine contactor contains stainless steel structured packing. The design lean amine circulation rate to the Dayung gas contactors is about 1640 US gpm and the design lean amine circulation rate to GLT gas is about 1621 USgpm based on maximum allowable rich amine loading of 0.49 mole (CO2+H2S)/mole UCARSOL (MDEA solution). The rich amine from the contactors flows under level control to the rich amine flash drums. Gas from the flash drums flows under back pressure control to the waste gas incenerators. The rich amine flows under level/flow control through the lean/rich amine exchangers where it is heated to about 206 oF by heat exchange with the hot lean amine from the two regenerators.
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The rich amine feeds the regenerator above the stripping section which contains stainless steel structured packing. CO2 and H2S are stripped from the rich solution by steam produced in the regenerator reboilers which consist of 4 (four) kettle type shell and tube heat exchanger for each regenerator. B. PERFORMANCE The main equipment of amine system are Regenerator Reflux Condenser 25-E101/202, Amine Reg. Reboiler 25-E-102A-D /202A-D , Lean amine cooler 25-E103/203, Rich / Lean Amine Exchanger 25-E-104A/B, 25-E-204A/B; Amine Charge Pump 25-P-102A/B/C; Amine Booster Pump 25-P-101B/C Table 4-9 : Performance of Amine Regenerator Re-boiler:
25-E-102A-D
25-E-202A-D
DESIGN
Pressure, psig
63.00
OFF
50.00
Temp sat'd steam, F
300.00
OFF
297.00
Flowrate Steam (25-FIC-121), Lb/hr
101,954.00
OFF
101,564.00
Flowrate Steam (25-FIC-122), Lb/hr
102,586.00
OFF
101,564.00
259.50
OFF
261.00
1,309,729
OFF
1,299,665
44.25
OFF
39.25
184,589,323
OFF
194,088,804
132
OFF
173
STEAM SIDE (SHELL):
AMINE SIDE (TUBE): Temp amine to Regenerator, F Flow of Rich Amine to be regenerated, Lb/hr Delta T HEAT DUTY, Btu/hr HEAT TRANSFER RATE, BTU/(HR.Ft2.degF)
The above table shows that the actual heat duty is closed to the design. The difference between actual heat duty and design value only 5%, although the flow rate regenerated rich amine higher than design, the temperature outlet of amine reboiler less than design (actual is 249.5 deg F and design value is 262 deg F). The overall heat transfer rate (U) at actual condition is 132 BTU/(Hr/Ft2.F) compare the design is 173 BTU/(Hr/Ft2.F. This condition caused by the LMTD of actual is higher than design value.
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Table 4-10 : Performance of Lean Amine Cooler : 25-E-103
25-E-203
DESIGN
Pressure, psig
110.00
110.00
180.00
Temp inlet, F
190
190
224
Temp outlet, F
106
104
120
799,305
670,882
1,375,016
Temp inlet, F
92
92
95
Temp outlet, F
129
129
141.3
Delta T LMTD
31.93
30.14
48.20
62,223,295
53,469,455
123,624,938
336.84
367.46
447.60
ACTUAL FAN OPERATED
11
12
12
CALCULATE FAN OPERATED
6
5
12
HEAT TRANSFER RATE, BTU/(HR.Ft2.degF)
2
2
3
LEAN AMINE side:
Flowrate of Lean Amine, Lb/hr AIR COOLANT side:
HEAT DUTY, Btu/hr ELECTRIC CONSUMPTION, KW
The above table shows that the heat duty actual of 25-E-103 and 25-E-203 are operated at 50% to the design. This caused by the flow rate of lean amine to be cooled also only about 50% - 60% from design capacity. The flow rate of lean amine does not affect to the power required of fan cooler driver, so the power required to motors also higher than calculated value. At this case, the actual fan be operated closed to design (11 fans for 25-E-103 and 12 fans running for 25-E-203). This condition related with performance of cooler, especially with heat transfer rate. The U (overall heat transfer rate) at operating condition give value about 2 BTU/(Hr/Ft2.F) for operated and 3 BTU/(Hr/Ft2.F for the design value. This difference indicated that the performance of cooler lower than the design performance. Table 4-11 : Performance of Rich-Lean Amine Exchanger: 25-E-104A/B
25-E-204A/B
108.00 155.00 203.00
OFF OFF OFF
DESIGN
RICH AMINE SIDE Pressure, psig Temp inlet, F Temp outlet, F
95.00 167.00 206.00
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Flowrate of Rich Amine, USGPM LEAN AMINE SIDE Temp inlet, F Temp outlet, F Delta T LMTD HEAT DUTY, Btu/hr HEAT TRANSFER RATE, BTU/(Hr/Ft2.F)
Page 73 of 109
2,572.00
OFF
2,496.80
250.00 229.00 59.48
OFF OFF OFF
261.00 224.00 55.99
53,656,356 N/A
OFF OFF
42,413,111 N/A
The above table shows that the heat duty operated of exchanger 25-E-104A/B is higher than design value. The difference is about 25% higher than design. The different heat load should be caused by :
Design amine is CR302, but the actual operation is AP-16668. The difference of amine causes different specific heat.
Flow rate of rich amine at operation is higher than the design value (3.5% difference)
The difference between operated LMTD and design is 6.5%.
Table 4-12 : Performance of Regenerator Reflux Condenser : 25-E-101
25-E-201
DESIGN
218.47 143.15 20.60
OFF OFF OFF
217.00 120.00 23.25
92.00 132.00 67.27
OFF OFF OFF
95.00 131.60 57.60
55,701,905
OFF
61,714,112
23.79 11.00 10.83 3.57
OFF OFF OFF OFF
29.84 12.00 12.00 4.19
ACID GAS SIDE : Temp inlet, F Temp outlet, F Flow of acid gas removed, MMSCFD AIR COOLANT SIDE : Temp inlet, F Temp outlet, F Delta T LMTD
HEAT DUTY, Btu/hr ELECTRIC CONSUMPTION, KW ACTUAL FAN OPERATED CALCULATE FAN OPERATED HEAT TRANSFER RATE, BTU/(HR.Ft2.degF)
The above table shows that regen reflux condenser and amine regenerator re-boiler are operated close to design condition. It has difference of heat duty about 11% than the design value. This caused by the flow rate of acid gas to be removed also only
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13% less than the design capacity (operated is 20.6 MMSCFD, and the design value is 23.25 MMSCFD). Power required of motor fan driver also proportional with the exchanger heat duty. At this condition the actual operate 11 fans, and the calculated result is also same fans to be operated. Caused by the flow rate capacity of cooler load, the overall heat transfer also follow with this condition. The U (overall heat transfer rate) at operating condition give value about 3.57 BTU/(Hr/Ft2.F) and 4.19 BTU/(Hr/Ft2.F for the design value. Table 4-13 : Performance of Amine Charge Pump DESCRIPTION
UNIT
25-P-102C
Design
value
value
specific gravity
1.03
1.00
245.00
70.00
Temperature
F
suction pressure
psia
98.00
25.00
discharge pressure
psia
1210.00
1185.00
flow
GPM
2862.00
2487.00
Total head
ft
2,503.97
2679.60
Electric motor power
HP
2240.00
2059.00
Mechanical work
HP
1946.39
1719.89
Efficiency
%
86.89
83.53
Only one Amine charge pump (Charge pump C) was running very close to design condition. It’s efficiency reached 86.89% with flow rate of 2862 GPM, This pump is designed to running with 83.53% efficiency at 2487 GPM flow rate. The pump was running actually in even higher efficiency than the design condition. Attention should be addressed to this situation since the pump draw consumed electric power of 2240 HP. It just below it's maximum power rating: 2250 HP. Table 4-14 : Performance of Amine Booster Pump DESCRIPTION
UNIT
specific gravity
25-P-101B
25-P-101C
Design
value
value
value
1.03
1.03
1.00
180.00
180.00
70.00
Temperature
F
suction pressure
psia
16.70
18.70
N/A
discharge pressure
psia
119.70
129.70
N/A
flow
GPM
1556.00
1306.00
2871.00
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Total head
ft
231.93
249.95
188.00
Electric motor power
HP
142.00
136.00
170.00
Mechanical work
HP
98.02
88.66
139.30
Efficiency
%
69.03
65.19
81.94
Two of the Amine booster pumps were running. They were Amine Booster pump B and C. Their efficiencies are 69.03% at 1556 GPM and 65.19% at 1306 GPM respectively. At the other side, we have data from design condition when each pump handles 2871 GPM. At this design condition, we got 81.94% efficiency. These two pumps were running in good condition and within the range of operation. 4.2.3. REFRIGERATION SYSTEM A. DESCRIPTION Propane refrigerant gas from gas chiller at 75 psig, compress by propane compressor (single stage screw compressor). The compressor discharge at about 252 psig goes to the propane condenser where it is totally condensed at about 122 oF. The propane condenser is an air cooled heat exchanger. The condensed propane goes to the propane accumulator and then to the gas chiller via the level control valve. The refrigerant chills the sales gas from 57 F to 45 F and then goes to LTS to separate the gas from the condensate. B. PERFORMANCE The main equipment at Refrigeration System are Exchanger (Gas chiller 30-E-102), Propane compressor 30-K-101A/B and Gas/Gas Exchanger. Table 4-15 : Performance of Gas Chiller UNITS
DESIGN
EVAPORATOR
TEMPERATURE GAS IN
DEG.F
57.00
57.00
TEMPERATUR GAS OUT
DEG.F
45.00
45.00
GAS FLOW
MMCFD
100.00
39.00
CONDENSATE FLOW
BCD
700.00
700.00
HEAT RELEASE
BTU/H
ACTUAL POWER
KW
C.O.P
2,477,633.80
841,348.85
260.00
110.00
2.79
2.24
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The above table shows that the refrigeration system operated at low load and the propane chiller are operated at 40 % load (39 MMSCFD ) at actual power 110 KW compare to design condition. The COP at actual condition is 2.24 compare to design value is 2.79 Table 4-16 : Performance of propane compressor Only one compressor is operated to handle the refrigeration system. The operating conditions are as follows;
UNITS SUCTION TEMPERATUR
DESIGN
ACTUAL
o
35.00
30.00
o
127.00
120.00
14,000.00
7,191.72
( F)
CONDENSING TEMPERATUR
( F)
PROPANE FLOW
LBS/H
TOTAL POWER REQUIRED
KW
242.17
101.64
ACTUAL POWER
KW
260.00
110.00
3.00
2.87
COP
(Calculated)
At the actual condition, the refrigerant flow is 7191 lb/hr at actual power 110 KW and COP = 2.87. Compare to design condition, the refrigerant flow is 14,000 lb/hr at power design 260 KW and COP = 3. It means that the performance of compressor is still in good condition. Table 4-17 : Performance of Gas/Gas Exchanger 30-E-101
DESIGN
Pressure, psig
1000
1120
Temp inlet, F
130.00
129.60
Temp outlet, F
60.00
64.40
Flow rate of Gas, MMSCFD
39.39
114.00
Temp inlet, F
40.00
50.00
Temp outlet, F
120.00
117.00
HOT GAS (FR GELAM CONTACTOR):
GELAM SALES GAS side:
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Delta T LMTD HEAT DUTY, Btu/hr
Page 77 of 109
14.43
13.48
3,159,954
10,705,230.41
0.23
0.30
2
HEAT TRANSFER RATE, BTU/(Hr/Ft .F)
The above table shows that gas/gas exchanger at the dew point control system have heat duty only 30% refer to the design value. This caused by the flow rate of gas also only 35%. The temperature profile of gas also not have high different between operated and design value. Caused by the flow rate capacity of gas to the gas/gas exchanger, the overall heat transfer also follow with this condition. The U (overall heat transfer rate) at operating condition give value about 0.23 BTU/(Hr/Ft2.F) and 0.30 BTU/(Hr/Ft2.F for the design value. 4.2.4. CONDENSATE STABILIZING SYSTEM A. DESCRIPTION The hydrocarbon liquid from the feed drum is fed under level control to the top tray of the condensate stabilizer. The stabilizer is a 32 inch ID reboiled stripping column containing 18 stainless steel valve trays. The stabiliser reboiler is a kettle type shell and tube exchanger utilizing about 3404 lb/h of 140# steam at normal operation. During normal operation about 1738 bbl/day of 10 psi RVP condensate are produced. The condensate product from the stabilizer is sent via the HC condensate cooler bundle in the refrigerant condenser air cooled exchanger frame. B. PERFORMANCE The main equipment at Condensate Stabilizing system are Stabilizer Re-boiler 35-E102, and Condensate cooler 35-E-101 Table 4-18 : Performance of Stabilizer Reboiler 35-E-102 : 35-E-102
DESIGN
Pressure, psig
117.00
150.00
Temp sat'd steam, F
330.00
330.00
Flow rate (35-FIC-006), Lb/hr
803.00
3,751.35
Temp Condensate to re-boiler, F
278.00
261
Delta T
66.00
69.40
STEAM SIDE (SHELL)
CONDENSATE SIDE (TUBE)
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HEAT DUTY, Btu/hr
Page 78 of 109
700,201
3,470,000
6.52
30.73
HEAT TRANSFER RATE, (BTU/Hr.Ft2.F)
The above table shows that actual heat duty of 35-E-102 is only 20 % compare to design condition because the flow rate of feed liquid to the stabilizer is only 20 % - 25 % compare to design. Due to the flow rate of stabilizer re-boiler is only 20% than the design, the U (overall heat transfer rate) at operating condition give value about 6.52 BTU/(Hr/Ft2.F) compare with the design value, 30.73 BTU/(Hr/Ft2.F Table 4-19 : Performance of Propane Condenser and Condensate Cooler 30-E-105 FLUID SERVICES:
DESIGN
PROPANE COONDENSOR
35-E-101
DESIGN
CONDENSATE
Pressure, psig
150
250
Temp inlet, F
140.00
158.00
316
316.00
Temp outlet, F
119.00
124.00
120
120.00
4.50
5.13 1324
2,174
Flow rate, MMSCFD (gas) Flow rate, BBL/day (liquid) AIR COOLANT SIDE : Temp inlet, F
92.00
95.00
92
95.00
Temp outlet, F
105.00
109.90
105
109.90
Delta T LMTD
30.83
35.30
53.68
85.85
3,086,550
3,796,245
718,616
1,995,227
14.72
22.38
14.72
22.38
HEAT DUTY, Btu/hr ELECTRIC CONSUMPTION, KW
The arrangement of cooler in this area is designed to serve three stream cooling fluid, i.e : Propane condenser, Propane overhead condenser and condensate stabilizer. Only one fans cooler installed to cool them. At the plant survey, the propane overhead condenser was off. Heat Load total at actual condition of two condenser (30-E-105 and 35-E-101) are 3.8 MMBTU/hr compare with the design value is 5.7 MMBTU/hr. This heat load gives
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percentage about 65 % of heat load capacity similar with electrical consumption is 65 % too. 4.2.5. DEHYDRATION SYSTEM A. DESCRIPTION The water saturated gas from the three amine trains is dehydrated by contacting it with lean triethylene glycol (TEG) in the three, identical glycol contactors. The design water content of the dry gas is 10 lb H2O per MMSCFD. The dehydrated GLT gas is recombined with the GLT amine unit bypass gas, sent through the dewpoint unit and then to sales. The Dayung/Suban gases from two of the glycol contactors and the Dayung/Suban amine unit bypass gas are sent directly to Sales. Lean glycol is fed to the top of the glycol contactor at a rate of about 30-USgpm. A coil is provided in the top of the tower to cool the glycol from about 210 oF to less than 150 oF by heat exchange with the dried gas leaving the contactor. The glycol flows downwards through the structured packing in the column counter-currently contacting and absorbing water from the gas flowing upwards through the packing. The rich glycol accumulates on the chimney tray and is sent under level control to the glycol regeneration skid. The dry gas exits the top of the contactor with the Dayung/Suban gasses going to sales and the GLT gas going to the hydrocarbon dewpoint control unit. The three glycol regeneration skids are identical. There are no connections between the glycol regeneration skids or between the glycol lines in each train. B. PERFORMANCE Table 4-20 : Performance of Rich – Lean Glycol Exchanger 41-E-101
41-E-201
41-E-301
DESIGN
Pressure, psig
10.50
11.50
11.00
50.00
Temp inlet, F
380.00
370.00
360.00
360.00
Temp outlet, F
150.00
165.00
160.00
225.00
Flow rate of Lean TEG, USGPM
20.18
24.00
24.00
30.48
Temp inlet, F
140.00
142.00
140.00
171.00
Temp outlet, F
200.00
200.00
196.00
306.20
Delta T LMTD
58.82
61.13
66.25
51.90
1,400,267
1,477,137
1,439,554
1,485,141
LEAN TEG SIDE
RICH TEG SIDE
HEAT DUTY, Btu/hr
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HEAT TRANSFER RATE, BTU/(Hr/Ft2.F)
104.88
Page 80 of 109
88.55
92.66
128.20
The above table shows that Rich/Lean Glycol Exchanger are operated close to design condition. Its heat duty is only 5% differ than the design value, although the flow rate of glycol at the operation only 70% - 80% than design capacity. This condition is caused by the difference of LMTD between operated and design value. The operating condition gives temperature outlet of Lean glycol lower than design value. Due to the flow rate capacity of cooler load, the U (overall heat transfer rate) at operating condition give value about 70%-80% than the design value. Table 4-21 : Performance of Glycol Heater 2-Oct-07 41-H-101
41-H-201
1 FUEL, Flow, MMSCFD
0.02
0.02
T out, F
430.00
430.00
O2, %
7.00
7.00
Excess Air, %
45.77
45.77
Heat absorption (LHV), MMBtu/hr
0.91
0.91
Heat absorption (HHV), MMBtu/hr
0.92
0.92
Efficiency (LHV), %
84.91
84.91
Efficiency (HHV), %
77.08
77.08
CO2 Emission from fuel gas, lb/hr
191.42
191.42
2 FLUE GAS
3 PERFORMANCE
4 CO2 EMISSION
The heat duty of Glycol heater is 0.91 mmbtu/hr (calculated from process site). Assuming the oxygen content of flue gas is 7%, the calculated efficiency is 84.91%.
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4.2.6. WASTE HEAT BOILER A. DESCRIPTION Permeate gas from membranes, rich amine flash drum gas, and acid gas from the amine reflux accumulators are combined and sent to the waste gas incenerator. In the incenerator, the waste gas is incenerated by burning fuel gas at a sufficient high temperature to ensure the complete destruction (oxidation) of the H2S and hydrocarbons. The minimum exit gas temperature at the top of the stack is 450 oF to ensure that the allowable ground level SO2 concentration is not exceeded. 150 psig saturated steam is produced by two heat recovey boilers with each capacity of 230,000 lb/h. Normally, two boilers are operated to supply necessary steam for all users in CGP. B. PERFORMANCE The main equipment of Waste Heat Boiler system are Waste Heat Boiler 46-B101/201, and BFW pump 46-P-102A/B/C. Table 4-22 : Performance of Waste Heat Boiler 2-Oct-07
DESIGN
46-B-101
46-B-101/102
1 INLET GAS, Fuel Gas Flow, MMSCFD
1.55
1.77
Acid Gas Flow, MMSCFD
20.23
48.11
Permeat Gas Flow, MMSCFD
8.35
68.39
T out, F
376.00
416.00
O2, %
7.00
2.62
Excess Air, %
45.77
13.17
lb/hr
200,392.00
245,000.00
T in Economizer, F
200.00
251.00
T out Evaporator, F
347.00
375.00
P in Economizer, Psi
132.40
175.70
P out Evaporator, Psi
123.00
170.00
2 FLUE GAS
3 BFW
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4 PERFORMANCE Heat Release (LHV), MMBtu/hr
149.52
822.94
Heat Release (HHV), MMBtu/hr
164.41
Heat Loss (LHV), MMBtu/hr
29.91
Heat Loss (HHV), MMBtu/hr
43.92
Heat absorption (LHV), MMBtu/hr
119.60
Heat absorption (HHV), MMBtu/hr
120.49
Efficiency (LHV), %
79.99
no Dsg Eff
Efficiency (HHV), %
73.29
no Dsg Eff
CO2 Emission from fuel gas, lb/hr
29,070.86
no Dsg CO2
CO2 Emission from Acid gas, lb/hr
103,029.15
no Dsg CO2
CO2 Emission from Permeat gas, lb/hr
42,586.20
no Dsg CO2
Total CO2 Emission, lb/hr
174,686.21
no Dsg CO2
380.55
442.38
5 CO2 EMISSION
The above table shows that the WHB are operated at only 50 % load compare to design condition, and the calculated efficiency is 80%. The temperature in flue gas are lower than design condition and the excess air is higher than design. Table 4-23 : Performance of BFW Pump
DESCRIPTION
UNIT
specific gravity
46-P-102A
46-P-102C
Design
value
value
value
1.00
1.00
1.00
245.00
245.00
70.00
Temperature
F
suction pressure
psia
21.10
21.10
8.00
discharge pressure
psia
274.70
274.70
230.00
flow
GPM
380.00
380.00
528.00
Total head
ft
585.82
585.82
512.82
Electric motor power
HP
95.00
95.00
110.00
Mechanical work
HP
57.45
57.45
69.88
Efficiency
%
60.48
60.48
63.53
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Like Amine booster Pumps, the two BFW pumps were running within the specification, and the efficiency reached is accepted. This BFW pump is designed to run with 63.53% efficiency at 528 GPM flow rate. Actually, two pumps were running at same rate of flow (380 GPM) with 60.48% efficiency. 4.2.7. GAS TURBINE GENERATOR A. DESCRIPTION Electrical power is generated and distributed to provide the prower requirements for the gas plant and offsites. Electrical power Generator driven by Gas turbine generator, which gas supplied from HP (high pressure) fuel gas system. Three gas turbine are provided with two generator running and one on the standby mode. The design capacity of generator is 4500 kW each unit. The actual capacity on the field survey only about 2100 kW each turbine generator (45% of design capacity) and running two of three generators. Generator specification is power 4688, voltage 4160, freq 50 Hz, cos Q 0.85. The large motor (lean amine charge pump, WHB Blower, propane compressor) supply by 6600 volt and the other motors using 400 volts. B. PERFROMANCE Gas turbine generators at Utility system are 47-GTG-101A/B/C Table – 4.24 : performance of GTG 2-Oct-07 47-GT-101A
DESIGN
47-GT-101B
47-GT-101A/B/C
TURBINE Fuel gas : flow, MMSCFD
0.89
0.92
1.31
Temperature, F
0
0
900
O2, %
16
16
16
Excess Air, %
296
281
267
Turbine Eff, %
21
21
30
Btu/kwh
16,571
16,077
11,559
lb/hr
4,870
5,034
7,914
Power Output, KW
2,158
2,265
4,688
PF
0.81
0.83
0.84
Flue gas :
CO2 Emission GENERATOR
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V
4160
4160
4160
Frequency, Hz
50
50
50
The above table shows that GTG operated at 50 % load compare to design condition. The calculated efficiency is only 21 % compare to design which is 30 %. The decreasing of efficiency of GTG is caused by low load and will be impact the increasing of the heat loss, The heat rate of 47-GT-101A is 16,571 Btu/kwh, greather than design 16000 Btu/kwh but 47-GT-101B 16,077 Btu/kwh close to design. Table 4-25 : The design performance of GTG are as follows POWER
4500
4000
3500
3000
2500
2000
1500
1000
BTU/KWH
11600
12000
12600
13000
14000
16000
18700
25000
4.2.8. AIR COMPRESSOR A. OPERATION Instrument and utility air are supplied by the two 340 scfm, screw type compressor connectod in a lead-lag configuration. The compressed air is filtered and then dried in heatless adsorption type dries which are on automatic regeneration cycles. The instrument air compressor packages are provided with local electronic control panels. The instrument air receiver is normally operated between 110 and 120 psig. The utility air take-off is equipped with a shut off valves to prevent utility air usage from drawing down the instrument air pressure. B. PERFORMANCE There are three compressors Atlas Copco GA 75 , 51-A-101A /B/C with design capacity is 340 SCFM, the performance of each equipment are as follows, Table 4-26 : Performance of air compressor : UNITS
DESIGN
ACTUAL
SUCTION PRESS
PSI
14.70
14.70
DISCHARD PRESS.
PSI
182.00
132.30
COMPRESS AIR FLOW
SCFM
340.00
257.45
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KW
ACTUAL PERFORMANCE
Page 85 of 109 72.60
44.17
0.20
0.20
The above table shows that the compressor is operated at low load. performance can not be evaluate accurately because no flow meter of air
The
4.2.9. ELECTRICAL MAP CENTRAL GRISSIK GAS PLANT Electric map for Central Grissik Plant is like the one for Suban Gas plant. It is derived from single line diagram, and intend to get a closer and clear point of view to one that need brief description on power consumption at each process. It Emphasize the voltage, and power required for each equipment. The power mentioned at each equipment is the power in normal design condition. A. Amine System
4.16 KV 25-P-102 A/B/C Amine Charge pump A/B/C 2250 HP x3
480 V 25-EM-103 A-M 25-PM-101 A/B/C Lean amine booster pump A/B/C Lean Amine cooler fan A-M 37.3 KW x13 200 HP x3
25-EM-201 A-M Regenerator reflux condenser fan A-M 29.8 KW x13
25-PM-105 Amine Transfer pump 9 HP
25-PM-104 Amine Sump pump 15 HP
25-EM-203 A-M Lean Amine cooler fan A-M 37.3 KW x13
25-EM-101 A-M Regenerator reflux condenser fan A-M 29.8 KW x13
25-AM-101/102 25-PM-203A/B Anti foam injection pump Regenerator reflux pump A/B 7.50 HP x2 2 HP x2
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B. Propane Chiller System 4.16 KV
30-K-101 A/B Propane Compressor A/B 350 HP x2
480 V 30-K-101A/B-PM1 30-PM-103 Propane Compr. A L.O. pump motor Propane Transfer pump 5 HP x2 3 HP
30-K-101A/B-KM1 Propane Compr. A/B L.O. cooler fan 5 HP x2
C. Depropanizer and Condensate Stabilization System
480 V
30-PM-102 30-PM-101 Depropaniser reflux pump Depropaniser feed pump 3.5 HP
5 HP
30-EM-105 A/B 30-E-104 Depropaniser reboiler heater Propane condenser fan A/B 22.3 KW x2 69 KW
35-PM-102 A/B Condensate shipping pump A/B 75 HP x2
D. Dehydration System 480 V 41-PM-101 41-PM-102/2020/302 A/B Glycol transfer pump Glycol circulation pump 1.74 HP 25 HP x6
E. Incinerator/Heat recovery System
4.16 KV 46-K-101/201 Inc. Blower train A/B 400 HP
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F. BFW steam and Condensate System 480 V 46-PM-102 A/B/C BFW pump A/B/C 150 HP
46-PM-103 A/B Condensate pump A/B 25 HP x2
46-EM-101 A/B Excess steam condenser fan A/B 22.3 HP x2
G. Flare and Air compressor System 480 V 48-PM-101 A/B Flare KO drum pump A/B 3 HP x2
51-AM-101 A/B Instr. Air compressor A/B 125 HP x2
51-AM-101 A/B -2 Instr. Air compressor A/B cooler fan 4 HP x2
H. Utility System
480 V 55-PM-201 A/B 54-PM-201 A/B Utility water pump A/B Portable water pump A/B 15 HP x2 7.5 HP x2
4.3.
53-PM-201 A/B Softened water pump A/B 7.5 HP x2
FINDINGS AND RECOMMENDATION
1. Instrumentation and Metering Based on the site survey founded that many metering and instrument are not work properly. Findings and recommendations of metering and instrumentation at Grissik Central Gas Plant are as follows :
Equipments 1.
WHB
Findings
There are unbalance between BFW flow and steam flow that will impact the direct method efficiency calculation is not accurate. Oxygen analyzer not work properly ( direct measurement = 7 % , on
Recommendations
Need to calibrate meter of steam and BFW
Need to install sampling point to measure Boiler water quality and control the blow down
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line analyzer = 14 %)
2
Glycol Regen Heater
3
2.
&
GTG
No Sampling point for water quality at steam drum
No meter fuel gas at the heater
need to install fuel gas meter
The position of flue gas sampling point is far from platform
need to install sampling line of flue gas close to the platform
There are no flow meter of fuel gas in each GTG.
Need to install flow meter of fuel gas
Need to install sampling line of flue gas for each GTG
4
Propane Comp
No continue record of electric consumption for motor compressor
Need to continously
5
Electric Distribution
No continue recorded for electric distribution
Need to record electric distribution (4160 line) at daily records
records
Waste Heat Boiler
Calculation result of WHB : EFFICIENCY
HEAT ABSORB
CO2 EMISSION
%
MMBtu/hr
Lb/hr
DESIGN
N/A
442.38
N/A
46-B-101
79.99
119.60
174,686.21
46-B-102
OFF
OFF
OFF
W H B - INCENERATOR 46-B-101
Finding :
WHB is operated at high excess air (77 %) compare to the design figure which is 27 % excess air. The efficiency is 80 %
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WHB is operated at low load ( 50 % load)
Recommendation :
WHB should be operated close to the design excess air
3. Heater Calculation result of heater : EFFICIENCY %
HEAT ABSORB MMBtu/hr
CO2 EMISSION Lb/hr
GLYCOL HEATER : 41-H-101 DESIGN 41-H-101 41-H-201
84.91 84.91
0.91 0.91
191.42 191.42
REG GAS HEATER : 21-H-101/201 DESIGN 21-H-101 21-H-201
74.62 74.65 OFF
11.06 5.75 OFF
2,651.23 1,376.93 OFF
Finding : The heater are operated at low load (50 % load) 4. GTG Calculation result of GTG : EFFICIENCY % GAS TURBINE GENERATOR DESIGN 47-GT-101A 47-GT-101B 47-GT-101C
29.52 20.59 21.23 OFF
HEAT RATE BTU/KWH
11,558.78 16,571.34 16,077.04 OFF
BHP KW
CO2 EMISSION Lb/hr
4,687.50 2,158.33 2,264.58 OFF
Findings : GTG are operated at lower load is around 50 % compare to design, but the performance ( heat rate ) are still close to design at low load
7,914.10 4,869.94 5,034.10 OFF
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5. Propane Comp Calculation result of Propane Compressor : POWER REQUIRED, KW DESIGN 30-K-101A
242.17 101.64
ACTUAL POWER, KW
260.00 110.00
PROPANE FLOW
COP
14,000.00 7,191.72
3.00 2.87
Findings : Based on the actual data, the refrigeration load is only 50 % compare to design condition, but the COP is 2.87 compare to design COP is 3. It means that the compressor is still in good condition 6. Gas Chiller Calculation result of gas chiller : UNITS GAS INTAKE TEMP.AT EVAP. GAS OUTPUT TEMP.AT EVAP. SALES GAS FLOW CONDENSATE FLOW HEAT RELEASE TOTAL POWER C.O.P
DESIGN
DEG F DEG F MMCFD BBL/D MMBtu/hr KW
GAS CHILLER
58.00 45.00 100.00 700.00 2,645,934.62 260.00 2.98 (Calculated)
Findings :
the temperature indicator inlet and outlet are still in good conditions
COP at gas chiller is 2.24 compare to design 2.98
57.00 45.00 39.00 700.00 841,348.85 110.00 2.24
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7. Air cooler Calculation result of coolers are as below:
No.
COOLER
HEAT DUTY (MMBTU/HR)
1.
Amine Regen Reflux Cooler 25-E-101 55.70 25-E-201 OFF Lean Amine Cooler 25-E-103 62.22 25-E-203 53.47 Stab. Condensate Cooler 35-E-101 0.72 Propane Condenser Compressor Cooler 30-E-105 3.09 Propane Ovhd Cooler 30-E-103 OFF
2.
3. 4. 5.
HEAT TRANSFER RATE
ELECTRIC/HEAT DUTY
(BTU/HR.FT2.oF)
(%)
3.57 OFF
1.60% OFF
2.06 1.88
1.85% 2.34%
5.03
8.85%
2.89
1.63%
OFF
OFF
Findings :
Power rated required for drive motors of fan coolers are below 1% - 2% due to their heat duties, except for Lean Amine 25-E-203 and Condensate cooler (25-E-101). This case indicate that power consumption of these coolers more waste energy (less efficiency).
Recommendations :
Need to check the cooler system of Lean amine cooler, because at the plant survey, they have high power consumption although the capacity of heat load only a half than design.
Need to check again the properties of amine used in operation, because it can effect the calculation performance of cooler and exchanger system in amine system.
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8. Heat Exchanger Calculation result of heat exchangers are as below: No.
HEAT EXCHANGER
1.
HEAT DUTY
DIRTY FACTOR
(MMBTU/HR)
HEAT TRANSFER RATE (BTU/HR.FT2.oF)
ACTUAL
DESIGN
ELECTRIC/ HEAT DUTY (%)
21-E-101
0.97
6.90
0.063
0.002
-
21-E-201
OFF
OFF
OFF
OFF
OFF
21-E-102
4.67
4.46
0.005
0.002
-
21-E-202
OFF
OFF
OFF
OFF
OFF
Rich/Lean Amine Exchanger 25-E-104A/B
53.58
N/A
N/A
N/A
-
25-E-204A/B
OFF
OFF
OFF
OFF
OFF
Rich/Lean Glycol Exchanger 41-E-101
1.40
104.88
0.002
0.001
-
41-E-201
1.73
117.99
0.001
0.001
-
41-E-301
1.67
111.25
0.001
0.001
-
Gas-Gas Dew Point Control HE 30-E-101
3.16
0.29
0.09
0.10
-
184.59 OFF 0.70
132.16 OFF 6.52
0.002 OFF 0.001
0.001 OFF 0.001
OFF -
0.14
N/A
N/A
N/A
102.32%
Gas-Gas HE in TSA unit Regen HE:
Cooler HE:
2.
3.
4.
5.
Amine Regen Reboiler 25-E-102 A-D 25-E-202 A-D Stabilizer Reboiler 35-E102 Depropanizer Reboiler 30E-105
6. 7.
Findings :
Entirely, the performance of heat exchangers in Grissik plant still in good condition, except for Gas/GAs Exchanger in TSA unit is needed to check again for the fouling condition, because it’s dirty factor have higher than their specification (design).
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9. Gas Pretreatment & Membrane system CALCULATION OF MEMBRANE SYSTEM Membrane Separation Rate Design Value of Membrane Separation
0.321556 lbmole/ lbmole 0.511022 lbmole/ lbmole
HYDROCARBON SLIP Rate Design Value of Hydrocarbon Slip Rate
0.030709 lbmole/ lbmole 0.063241 lbmole/ lbmole
Findings :
The Thermal swing adsorber (TSA) system running on good condition, because the C6+ concentration at the feed gas to membrane is 29 ppm compare to the design is 39 ppm.
The membrane system separation only give separation rate is 32% compare to the design 50% of CO2 feed, so the CO2 content in gas to contactor still high than design value.
Recommendation :
Need to check again the membrane module system to upgrade the separation rate.
10. Amine System Findings :
The absortion rate capacity of amine contactor is only 38% refer to the design capacity rate. This case caused by the flowrate of gas processing capacity of lean amine only 40% than design.
Recommendation :
Need to operate full gas processing capacity to increase absorption rate in amine contactor due to reduce the energy consumption in amine system
11. Energy Conservation a. Energy Losses : Based on heat balance calculation, energy losses from high temperature flue gas (more than500deg F) at Grissik is coming from Stack of GTG. Total losses is 57,821,543 Btu/hr.
STACK LOSS, Btu/hr
TEMP, Deg F
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GTG 247-GT-201A
30,471,332
949
247-GT-201B
27,350,211
967
247-GT-201C
0
0
57,821,543
958
TOTAL
Actually, by utilizing economizer with stack temperature around 500 deg F, this Fluegas losses can be used to generate saturated steam about 28,000 lb/hr.
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b. Potential Saving : Based on the evaluation, shows that the potential saving are coming from :
Optimize operation of WHB by reducing excess air (7 % O2 to 3% O2) increase efficiency aroumd 4 %, that will reduced LP fuel consumption to 0.06 MMSCFD
Utilized flare gas that will reduced fuel consumption to 1.0 MMSCFD
Energy Conservation Opportunities :
Optimized operation of GTG can be implemented by load shading
Optimized operation of Heater and utilized flare gas can be implemented by installing booster compressor to compress gas up to 180 psig. This fuel can be used for Gas turbine and in turn it will reduce HP Fuel consumption. The simple calculation are as follows :
WHB-saving, MMSCFD
0.06
, US $/Year
76,725.00
Flare Gas-saving, MMSCFD
1.00
, US $/Year
1,237,500.00 Total, MMSCFD
1.06
, US $/Year
1,314,225.00
*Cost to install the system for recovery gas which includes : gas compressor, KO Drum, Instrumentations , US $ Operation and Maintenance Cost , US $/year Net income , US $/Year
Estimated payback period to install the system , Years
3,000,000.00
120,000.00 1,194,225.00
2.51
* = refer to Beak Pacifik Report - Energy Audit at Cilacap Refinery Complex (Beak Pacific Inc. , Vancouver, Canada)
c. Emission Reduction Potentials CO2 emission at suban gas plant is 182,886 lb/hr. its come from combustion of fuel gas at flare gas, heater, WHB and GTG. Optimized operation and utilized flare gas can reduce CO2 emission around 5 %
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CO2 reduction, lb/hr utilized flare gas
8,507.79 Total
8,507.79
Utilized flare gas will reduce CO2 emission , %
5%
12. Reporting system Findings :
Existing daily report just for production activity it does not cover data for plant performance evaluation purpose
No data acquisition and evaluation based on daily log sheet .
Important data for plant performance not cover in daily log sheet
Recommendation :
Daily reporting must cover production activity and plant performance indicator
Regular summary of log sheet regarding plant performance should be evaluate.
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V. ENERGY ASSESSMENT AT RAWA PLANT 5.1 5.1.1.
OIL
GENERAL PLANT OPERATION AND PERFORMANCE PLANT OPERATION
There are wells at ConocoPhillips South Sumatra area that contents oil in significant amount and high gas concentration. Rawa plant is designed to process this oil, and re inject the gases to the injection wells. High-pressure oil & gas came firstly from wells entering the plant via manifold, before entering the production processes. The first process is High-pressure separator (HP separator). Oil, MP Gas and Water is separated in this process. MP gas (450 psig) leave the top separator and water leave the bottom of the separator and then store it in the production water tank before send to Central Ramba. Oil & LP gas mixture goes to medium pressure (MP) separator. In MP Separator, Oil & HP gas is separated. Oil is stored to the crude oil tank before ship to Plaju. LP Gas (50 psig) compressed by LP Gas compressor (gas engine) to raise it the pressure until 450 psig. MP gas from HP separator mix with MP Gas from LP Compressor and then the HP Compressor driven by gas turbine to rise the pressure until 1200 psig. Water content in HP Gas is reduced by glycol system before injected to the wells. The design of HP Compressor is 45 MMSCFD and about 1 MMSCFD of process gas used for fuel. The simplified process flow diagram of Rawa field is shown at diagram in figure 1.1
MP Gas
5 HP Compressor
Oil wells
2
1 HP Separator
Gas Scrubber
MP Separator
3
4 Prod water tank
To Ramba
LP Compressor
4 Oil Send to Plaju and Bentayan
Figure 5.1. (simplified)
Rawa prod. Block diagram
Injection To wells Glycol System
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Data from production records taken from 1-10 Aug 2007 at table 1 shows that oil extracted from wells is about 300-320 barrels/day (0.001%) and water produced is 1500-1600 (0.003%). About 21 MMSCFD gas derived is re injected to injection wells while the other product, i.e. fuel gas, is sent to Ramba station. Table -5.1 : Oil Production Data
5.1.2.
GENERAL PERFORMANCE EVALUATION
The Energy Source of Rawa oil Plant is LPgas used for gas turbine compressor (LP and HP) and Glycol Regenerator which comes from LP Separator. LP Compressor driven by gas engine to increase the LP Gas pressure from 60 psi to 450 psi and HP Compressor driven by gas turbine to increase the MP gas from LP Compressor and HP Separator to 1200 psi. Fuel flow meter only for total consumption. There is no flow meter for each consumers. The total consumption is 0.7 – 1.1 MMSCFD Rawa oil processing plant doesn't have electric power generation systems inside the plant itself. Electric power derived from Ramba power plant via medium voltage lines, 11KV, 3, 50 Hz. Incoming power line then is stepped down by a transformer to 380V/220V, 3, and in turn, this voltage system is applied to all the electrical equipments and machines inside the plant. There is no KW Meter in main panel. The estimate load is about 150 KW. For emergency purposes, there is a diesel fueled electric generator (380V, 3, 50 Hz) that has capacity of 505 KVA. This generator set needed extra maintenance due to this machine is of the old type, and have been used over a long period of time.
5.2
PERFORMANCE EVALUATION OF MAIN EQUIPMENT
The main equipment at rawa oil plant are . HP Compressor 5000-PK-100 , Compressor 5000-PK-101 and Glycol Reboiler 3600-HT-103 The performance of HP and LP Compressor are as follows :
LP
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HP Compressor 5000-PK-100 Table -5.2 : Performance of HP Compressor 5000-PK-100 UNITS
INJECTION GAS ABSL.SUCTION PRESSURE
(Ps)
ABSL. DISCHARED PRESSURE (Pd)
POWER REQUIRE
ACTUAL
DESIGN
MMCFD
39.20
45.00
PSIA
455.00
515.00
PSIA
1,165.00
1,465.00
HP
2,860
3,525
Injection gas flow at actual condition is 39.20 MMSCFD (87 % load) compare to design (45 MMSCFD) and power require is 2860 HP compare to 3525 HP Table -5.3 : Performance of turbine 5000-PK-100
A
21-Dec-07
DESIGN
HP Turbine 5000PK-100
HP turbine 5000PK-100
TURBINE Fuel gas : flow, MMSCFD
0.85
0.89
Temperature, C
1,062
900
O2, %
15
16
Excess Air, %
234
279
Eff, %
22
27
Btu/BHP
11,460
9,392
Flow, lb/hr
2,217
2,450
Power Required, KW
2,134
2,630
, HP
2,860
3,525
Flue gas :
CO2 emission : B
COMPRESSOR
Turbine is operated at 72 % load (2860 HP) compare to design (3525 HP) and heat rate is 11.460 Btu/HP compare to the design heat rate is 10500 Btu/HP.
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Table -5.4 : Design performance of turbines POWER,HP
4000
3500
3000
2500
2000
1500
1000
BTU/BHP
9500
9700
10500
11000
12000
12700
14000
LP Compressor 5000-PK-101 Table -5.5 : Performance LP Compressor 5000-PK-101 are as follows
UNITS INJECTION GAS
ACTUAL
DESIGN
MMCFD
6.00
15.00
PSIA
75.00
75.00
ABSL. DISCHARED PRESSURE (Pd)
PSIA
445.00
450.00
FUEL CONSUMPTION
MCFD
250.00
400.00
HP
533.05
1,439.09
19,541.46
11,581.36
ABSL.SUCTION PRESSURE
POWER REQUIRE ENERGY INTENSITY
(Ps)
Btu/HP
LP compressor is operated at low load (less than 40 %) compare to design it will impact the energy intensity very high (19,541 BTU/HP compare design value 11,581 BTU/HP)
5.3
FINDINGS AND RECOMMENDATION
Findings : A. Instrumentation
no flow gas meter for each gas consumer,
no control monitoring system that can be used to monitor the operation of the compressor from control room.
No meter indicators for electric equipments.
B. Compressor
Compressors is operated at low load for LP (less then 40%)
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HP compressor is operated 70% load compare to design, the heat rate is higher then design heat rate at 70 % load.
LP compressors shut down frequently and causing increase of flare gas from 1 MMSCFD to 4-9 MMSCFD.
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VI. PERFORMANCE MONITORING INDICATOR 6.1. EQUIPMENTS 6.1.1. Fired Heater Function : converting energy from fuel gas into thermal in order to increase the temperature of process fluid Key Performance Indicator : Efficiency which is consist of combustion efficiency and heat transfer efficiency Variable should be Measured :
% O2 in flue gas
Stack Gas Temperature
Ambient Temperature
Fuel gas flow, composition
Fuel gas heating value
Spread sheet : See Appendix no.6.1 6.1.2. Waste Heat Boiler Function : converting energy from fuel gas and permeat gas into thermal in order to produce steam and oxidize H2S from acid gas Key Performance Indicator : Efficiency which consist of combustion efficiency and Heat transfer efficiency Variable should be Measured :
% O2 in flue gas
Stack Gas Temperature
Ambient Temperature
Flow and composition of fuel gas, permeat gas and acid gas
Heating value of fuel gas, permeat gas and acid gas
Spread sheet : See Appendix no.6.2
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6.1.3. Gas Turbine Generator Function : converting energy from fuel gas to mechanical energy to produce electricity Key Performance Indicator : Efficiency which is consist of gas turbine efficiency and generator efficiency Variable should be Measured :
Fuel gas flow (input)
Fuel gas heating value (LHV)
Generator Output
Oxygen content in flue gas
Flue gas temperature
Spread sheet : See Appendix no.6.3 6.1.4. Gas Turbine Compressor Function : converting energy from fuel gas to mechanical energy to compress sales gas Key Performance Indicator :
Efficiency which consist of gas turbine efficiency and compressor efficiency
Energy Intensity which is representing by fuel gas divided by mechanical energy to compress sales gas
Variable should be Measured :
Fuel gas flow (input)
Fuel gas heating value (LHV)
Oxygen content in flue gas
Flue gas temperature
Suction and discharge pressure of sales gas
Flow of sales gas
Spread sheet : See Appendix no.6.4
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6.1.5. Air Compressor Function : converting energy from electricity to compress air Key Performance Indicator : Actual power / Qs x ((Pd/Ps)^0.2857 – 1) Note : Qs = air flow
Variable should be Measured :
Electricity power (input)
Pressure of compressed air
Spread sheet : See Appendix no.6.5 6.1.6. Propane compressor Functions : to evaporate refrigerant and to condense refrigerant vapor Key Performance Indicator : Coefficient of Performance (COP) Variable should be Measured :
Electricity power (input)
Evaporation Temperature
Condensing Temperature
Spread sheet : See Appendix no.6.6 6.1.7. Pumps Functions : to transfer or to lift up the liquid Key Performance Indicator : Efficiency which consist of pump efficiency Variable should be Measured :
Electricity power (input)
Liquid flow
Suction and discharge pressure
Spread sheet :
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See Appendix no.6.7 6.1.8. Air Cooler Functions : to cooling the fluid or to condense the vapor Key Performance Indicator : Overall heat transfer coefficient (U) Variable should be Measured :
Electricity power (input)
Liquid flow
Temperature and Pressure of fluid inlet and outlet
Composition of fluid
Spread sheet : See Appendix no.6.8 6.1.9. Heat Exchanger Functions : to transfer heat from high temperature to low temperature of fluid Key Performance Indicator : Overall heat transfer coefficient (U) Variable should be Measured :
Fluid flow
Temperature inlet and outlet of hot side and cold side
Operating Pressure of hot side and cold side
Composition of fluid
Spread sheet : See Appendix no.6.9
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6.2. SYSTEM 6.2.1. TSA System Functions : to reduce heavy hydrocarbon content of feed gas Key Performance Indicator :
Adsorption Rate
TSA Regeneration Rate
Variable should be Measured :
Feed gas flow
Temperature of feed gas
Pressure inlet and outlet gas
Composition of feed gas and outlet gas
Spread sheet : See Appendices no.6.10 6.2.2. Membrane System Functions : to reduce CO2 content of feed gas Key Performance Indicator :
Membrane separation rate
HC Slipped rate
Variable should be Measured :
mole CO2 in Permeate Gas
Mole CO2 in Feed Gas
mole HC in Permeate Gas
Mole HC in Feed Gas
Spread sheet : See Appendices no.6.11 6.2.3. Amine System Functions : to reduce acid gas (CO2 & H2S) content of treated gas
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A. Amine Contactor Functions : to absorb acid in treated gas by amine liquid Key Performance Indicator:
Absorbtion Rate
Variable should be measured:
mole-CO2 absorbed
Mole pure lean amine
Spread sheet : See Appendix no.6.12 B. Amine Regenerator Functions : to desorb/strip acid in rich amine by heating Key Performance Indicator:
Amine Regeneration Rate
Variable should be measured:
CO2 content in lean amine and CO2 content in acid gas flow
Quantity of steam or fuel gas consumption
Operating temperature and pressure of regenerator
Spread sheet : See Appendix no.6.13 6.2.4. Dehydration System Functions : to remove moisture in treated gas by glycol Key Performance Indicator:
Absorbtion Rate
Glycol Regeneration Rate
Variable should be measured:
Flow of gas and glycol
water content inlet and outlet of treated gas
water content in lean glycol
Operating temperature and pressure of contactor
Spread sheet :
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See Appendix no.6.14
6.2.5. Dew Point Control System A. Gas Chiller Functions : chilling treated gas Key Performance Indicator:
COP (heat released by fluid divide by power of compressor unit)
Variable should be measured:
Flow of sales gas and condensate
Composition of sales gas and condensate
Temperature inlet and outlet of chiller
Spread sheet : See Appendices no.6.15 B. Low Temperature Separator Functions : to separate of sales gas and condensate. Key Performance Indicator: Percentage of condensate content in sales gas compared to design value Variable should be measured:
Flow of sales gas and condensate
Composition of sales gas and condensate
Operating Temperature and Pressure of separator
Spread sheet : See Appendices no.6.16 6.2.6. Condensate Stabilizer Functions : to remove light hydrocarbon from condensate. Key Performance Indicator:
Yield of Stabilization
Stabilizer Performance
Variable should be measured:
Flow of raw condensate
Flow of treated condensate
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Composition of condensate
Flow of steam
Operating Temperature and Pressure of column
Spread sheet : See Appendix no.6.17 6.2.7.
Depropanizer
Functions : to produce propane. Key Performance Indicator:
Yield of Stabilization
Depropanizer Performance
Variable should be measured:
Flow of feed to column
Flow of propane product
Electric consumption
Operating Temperature and Pressure of column
Spreadsheet: See Appendix no.6.18
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Final Report ENERGY MANAGEMENT ASSESSMENT / AUDIT FOR PSC CORRIDOR (SUBAN-GRISSIK-RAWA)
COPI Doc No.:
Originator: COPI Group Owner: Area: Location: System: Document Type: Discipline / Sub discipline: Old COPI Document No.:
COPI UO – Engineering – Onshore Sumatra General General General System Final Report -
1
IFR
14 Dec 07
Issued for Review
2
IFR
14 Jan 08
Issued for Review
Rev
Status
Issue Date
Reason for Issue
Prepared
Checked
Approvals
Printed initials in the approval boxes confirm that the document has been signed. The originals are held within Document Management.
Final Report
ID-N-GN-00000-00000-00068
Energy Management Audit / Assessment for PSC Corridor ConocoPhillips Indonesia
Revision Sheet
Page 2 of 109
PT.E M I (Persero)
ConocoPhillips Indonesia Inc. Ltd
REVISION
DATE
DESCRIPTION OF CHANGE
1
14 Dec 07
Issued for Review
2
14 Jan 08
Issued for Review
Final Report
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Energy Management Audit / Assessment for PSC Corridor ConocoPhillips Indonesia
Page 3 of 109
CONTENTS I. INTRODUCTION II. METHODOLOGY 2.1
METHODOLOGY OF ENERGY ASSESSMENT
2.2
METHODOLOGY OF CALCULATION 2.2.1 CALCULATION OF EQUIPMENT 2.2.2 CALCULATION OF SYSTEM
III. ENERGY ASSESSMENT AT SUBAN GAS PLANT 3.1. GENERAL PLANT OPERATION AND PERFORMANCE 3.3.1. GENERAL PLANT OPERATION OF SUBAN GAS PLANT 3.3.2. GENERAL PLANT PERFORMANCE OF SUBAN GAS PLANT 3.2. PERFORMANCE EVALUATION EACH SYSTEM 3.2.1. SEPARATION & COOLER SYSTEM 3.2.2. AMINE SYSTEM 3.2.3. CONDENSATE STABILIZING SYSTEM 3.2.4. DEW POINT CONTROL AND REFRIGERATION SYSTEM 3.2.5. GAS COMPRESSION SYSTEM 3.2.6. GAS TURBINE GENERATOR 3.2.7. AIR COMPRESSOR 3.2.8. ELECTRICAL MAP SUBAN GAS PLANT 3.3.
FINDINGS AND RECOMMENDATIONS
IV. ENERGY ASSESSMENT AT GRISSIK CENTRAL GAS PLANT 4.1. GENERAL PLANT OPERATION AND PERFORMANCE 4.1.1. GENERAL PLANT OPERATION OF GRISSIK GAS PLANT 4.1.2. GENERAL PLANT PERFORMANCE OF GRISSIK GAS PLANT 4.2. PERFORMANCE EVALUATION EACH SYSTEM 4.2.1. GAS PRETREATMENT AND MEMBRANE SYSTEM 4.2.2. AMINE SYSTEM 4.2.3. REFRIGERATION SYSTEM 4.2.4. CONDENSATE STABILIZING SYSTEM
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4.2.5. DEHYDRATION SYSTEM 4.2.6. WASTE HEAT BOILER 4.2.7. GAS TURBINE GENERATOR 4.2.8. AIR COMPRESSOR 4.2.9. ELECTRICAL MAP CENTRAL GRISSIK GAS PLANT 4.3. FINDINGS AND RECOMMENDATIONS
V. ENERGY ASSESSMENT AT RAWA OIL PLANT 5.1. GENERAL PLANT OPERATION AND PERFORMANCE 5.2. PERFORMANCE EVALUATION 5.2.1. GENERAL PERFORMANCE 5.2.2. PERFORMANCE EVALUATION OF MAIN EQUIPMENT 5.3. FINDINGS AND RECOMMENDATIONS
VI. PERFORMANCE MONITORING INDICATOR 6.1. EQUIPMENTS 6.1.1. Fired Heater 6.1.2. Waste Heat Boiler 6.1.3. Gas Turbine Generator 6.1.4. Residue Gas Compressor 6.1.5. Air Compressor 6.1.6. Propane compressor 6.1.7. Pumps 6.1.8. Air Cooler 6.1.9. Heat Exchanger 6.2.
SYSTEM
6.2.1. Gas Pretreatment 6.2.2. Membrane System 6.2.3. Amine System
Amine Contactor
Amine Regenerator
6.2.4. Dehydration System 6.2.5. Dew Point Control System
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Gas Chiller
Low Temperature Separator
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6.2.6. Condensate Stabilizer 6.2.7. Depropanizer
APPENDICES 1.
SCHEDULE OF ENERGY ASSESSMENT/AUDIT
2.
MEASUREMENT DATA
3.
LABORATORY ANALYSIS
4.
LIST OF DATA HAS BEEN COLLECTED
5.
SPREAD SHEET OF EFFICIENCY AND ENERGY CONSUMPTION EQUIPMENTS
6.
SUBAN GAS PLANT
GRISSIK CENTRAL GAS PLANT
RAWA OIL PLANT
SPREAD SHEET OF PERFORMANCE MONITORING INDICATOR
EQUIPMENTS
SYSTEMS
7.
SIMULATION RESULT OF SUBAN GAS PLANT
8.
SIMULATION RESULT OF GRISSIK CENTRAL GAS PLANT
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I. INTRODUCTION As a part of energy management program, in the year of 2007 the Indonesia Business Unit of ConocoPhillips committed to develop plan regarding various efforts to conserve sources and to reutilize waste, energy utilization and to reduce emission reduction for each operating asset. Since 2004, emission level forecasts were generated as part of environmental performance report that shall be further followed up in actual action plans. This assessment is intended to guide the company in identifying energy-related business opportunities and appropriate methods and developing the strategic framework for realizing them. By performing this assessment / audit, it could also find emission reduction opportunities in onshore operating asset. The aim of this assessment is to identify where and how much energy is used in a facility and for determining energy saving and emission reduction opportunities in onshore operating asset. The objectives of this assessment / audit are as followed; 1. Provide clear direction or appropriate method as to potential inherent in a strategic approach to energy planning and management. 2. Define specific facilities that consume high energy and generate high emission. 3. To observe and evaluate the present situation of those plants in regards with energy consumption, process efficiency or performance and emission reduction opportunities. 4. Provide options based on a set of criteria (measures) and select the most promising options for implementation. 5. Provide recommendations and action plans in order to reduce energy consumption, increase plant efficiency and reduce emission rate in onshore operating assets by implementing energy diversification, energy efficiency and optimization and possibility to reuse energy waste. The Scope of this assessment / audit are as followed;, 1 Preliminary Energy Audit / Assessment which includes : Review and prepare additional information, Identification and inventory energy consumption and production data; Analyze data to determine which equipment will get high priority to be assessed and; prepare action plan to perform energy management audit / assessment 2 Performing Energy Audit / Assessment which includes : Identifies area of high energy usage and where energy waste occurs; Develop priorities for reducing energy waste and emission; Provides a criteria of measures which improvements could be implemented and; Generate spreadsheet for energy consumption per equipment
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3 Establish Calculation Performance Monitoring Indicators per equipment and system 4 Provide Recommendation for Improvements a part of COPI energy management program To achieve the targets and to establish interactive cooperation of involved personnel without disturbing surveyed objects routine activities, the procedure of the Energy Assessment / Audit at Suban Gas Plant, Grisik Central Gas Plant and Rawa Oil Plant are as follows: Preparation of the plant survey, Field inspection and data collection, Data verification (of the data collected) Discussion Data analysis and evaluation Preliminary report, Discussion Field verification Interim Report/Draft Final Report Presentation, Final Report. The preparation of the plant survey has been held on 10 – 21 September 2007. The activity are includes define the boundaries, define data to be collected, define instruments / meter related to the data to be collected and prepare checklist for interview. The Field inspection and data collection has been held on 24 September – 5 October 2007. The activity are includes collection of technical data of main energy-consuming equipment, operation data, historical data, interview data, and direct measurement with portable equipment. Principally, the data collected should be enogh to calculate material and heat balance in each equipment. During data collecting period at Suban Gas Plant, Grissik Central Gas Plant and Rawa Oil Plant, not all the data requirement for analysis has been collected. Some of the data are completed from COPI Office Jakarta and the other data are completed during 2nd field inspection. Direct measurement are done for all fired heater at Suban Gas Plant and Waste Heat Boiler at Grissik Central Gas Plant. In order to crosscheck the data gathered are accurate and reliable before carrying out analyses, it is need to do the data verification. The data verification, has been held on 8 - 10 October 2007 and the discussion regarding the result of data verification has been held on 23 October 2007. Data analysis and evaluation has been held on 22 October – 23 November 2007. The activity of the analysis are includes preparation of calculation methodology, spread
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sheet of equipment, develop heat and material balance, performance evaluation, identification/quantification of heat loss and calculation of energy conservation opportunities. The result of data analysis and evaluation are reported in the Preliminary Report on 26 November 2007 and discussion regarding this report has been held on 29 – 30 November 2007. 2nd field survey has been held on 3 – 7 December 2007 at Suban and Grissik. activity during 2nd field survey are includes :
The
Measurement of flue gas composition and temperature of Heater and Waste Heat Boiler. Electrical data records for rotating equipments. Presentation of draft final report has been held on 18-19 December 2007 The Schedule of Energy Assessment, data has been collected and measured, laboratory analysis are summarized in the appendices no.1 – no. 4.
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II. METHODOLOGY 2.1. METHODOLOGY OF ENERGY ASSESSMENT/AUDIT Obviously, the Methodology of Energy Assessment / Audit at Suban Gas Plant, Grisik Gas Plant and Rawa Oil Plant will involve :
Collect and Analyze Energy-Usage Data
Review, identify and inventory energy consumption data
Identify the main energy consumption system and equipments
Performance evaluation and identify the main energy consumption equipment.
Quantity energy waste and emission.
Recommendation.
The information regarding plant operation has been collected during data collection period from 24 September to 5 October 2007. The data will be used in the analysis are include;
Daily Log Sheets
Computer logged data (for Suban and Grissik)
Laboratory analysis
Direct measurement during plant survey
Design data
After all the data has been collected, It is need to develop mass balance of each unit in order to verify the accuracy of flow meter reading. If there are discrepancy between mass inlet and outlet, ones of the mass flow should be adjusted, and than the data that has been verified will be used as data basis for development of heat and mass balance each equipment and system. By using Spreadsheet and Process Simulation, a plant model will be created to calculate performance aspect of the equipments and compare with design or available references. The plant model spreadsheet is constructed based on material and energy balance each equipment, energy efficiency and losses. Process Simulation used to develop material and energy balance for overall process gas plant. Especially on the fired heater and waste heat boiler the spreadsheet is constructed based on the calculation of energy efficiency, losses and emission level of each equipment. Based on the data that has been collected, performance of each equipment, efficiency level, energy waste and emission reduction potential of equipment will be calculated and quantified.
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Based on the energy and emission reduction potential level of each equipment and refer to technical and financial criteria, recommendation for improvement measure will be identified. All of the results of the evaluation / analysis will be discuss, present and reported to ConocoPhillips. The reporting of energy assessment / audit wil include preliminary report, interim/draft final report and final report. The preliminary report which covers : energy audit methodology, all data collected, all formula for calculations and preliminary findings. The interim/draft final report which covers : energy audit methodology, all data collected, energy performance analysis result, quantity of all energy waste and emission, energy waste and emission reduction opportunities and performance monitoring system. The final report which contains of: executive summary, evaluation result during audit / assessment, spreadsheet of energy consumption, spreadsheet of performance monitoring indicators and detail recommendation report.
2.2. METHODOLOGY OF CALCULATION The methodology of calculation are developed in two model which includes the calculation of equipment and the calculation of process system.
The Calculation of Equipment are includes : Fired Heater; Waste Heat Boiler; Gas Turbine Generator; Residual Compressor; Air Compressor; Propane Compressor; Pumps; Air Cooler; Heat Exchanger .
The Calculation of Process system are includes : Separation system; Amine System; Dehydration System; Condensate Stabilizer System, Depropanizer System and Refrigeration System
All of the calculation are explained regarding the efficiency and performance of each equipment and process system.
2.2.1.
CALCULATION OF EQUIPMENTS
2.2.1.a. Fired Heater The biggest energy consumption in the operation of gas plant is fired heater, so the evaluation of fired heater especially the efficiency and performance are very important in this assessment.
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Page 11 of 109 %O2, T stack
Conv. Rad.
Ta(ambient air temp)
Flue Gas
AIR
FIRED HEATER
FUEL
Proc Fluid
T out
Proc Fluid
Fluid Flow T in
Efficiency of Fired Heater can be calculated in two ways ie. :
Direct Method
Heat Loss Method *
* Refer to Enercon Handbook a. Direct Method : The step of calculation are as follows, Calculate heat duty of fired heater, k cal/hr Calculate LHV of fuel gas (refer to lab test), kcal/hr heat duty of fired heater Efficiency =
X 100% LHV of fuel gas
b. Heat Loss Method Fired Heater Efficiency are calculated based on the heat loss of : dry flue gas H2O from combustion of H2 H2O moisture from fuel gas H2O moisture from air radiation and convection (refer to design)
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The step of calculation of heat loss method in the fired heater are as follows, a.
Measure Ta, Tstack and % O2 in flue gas
b. Calculate combustion air for stoichiometry condition c. Calculate excess air at % O2 as measure d. Calculate flue gas flow, kg/h (flue gas flow = fuel + comb air stoch + excess air) e. Calculate flue gas loss, kcal/hr (flue gas loss = flue gas flow x Cp x (Tst – Ta)) LHV of Flue Gas – flue gas loss – Rad & Conv Loss** Efficiency =
X 100% LHV of Fuel Gas ** Refer to design condition
The efficiency calculated from heat loss method can be used to check the accuracy of fuel gas flow meter recorded at each fired heater. The step of calculation are as follows : calculate heat duty of fired heater based on the different enthalpy of BFW (steam) inlet and outlet. calculate the heat release of fired heater based on the calculated efficiency (ie. the heat duty divided by efficiency). heat release from the calculation can be used to check the accuracy of fuel gas flow meter recorded at each fired heater
2.2.1.b. Waste Heat Boiler (WHB) The calculation methodology of WHB is similar with fired heater, the small different is in the calculation of steam flow which is calculated based on BFW flow rate minus blow down flow rate. Efficiency of Waste Heat Boiler also can be calculated in two ways ie. : Direct Method Heat Loss Method * * Refer to Enercon Handbook a.
Direct Method
Efficiency =
(Hst – HBFW) x ST.Flow
L.H.V. (Fuel Gas + Pem Gas + Acid Gas)
X 100%
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Page 13 of 109
% O2 , Tstack
Ta (ambient air temp) Flue Gas
Conv. Rad. AIR
Fuel Gas
Acid Gas
WASTE HEAT BOILER
Steam
Flow, P, Tsteam
Permeat Gas
Water
Blow Down
b. Heat Loss Method The step of calculation are as follows, a. Measure Ta, T stack and % O2 in flue gas b. Calculate combustion air of acid gas, permeate gas and fuel gas for stochiometry condition c. Calculate excess air at actual condition d. Calculate dry flue gas flow at actual conditions, kg/hr e. Calculate total loss, kcal/hr Total loss = dry flue gas loss + blow down loss + rad & conv. loss Dry flue gas
= flue gas flow x Cp x (Tst – Ta)
Blow down loss = % blow down *x ST. Flow x ( H Saturate – HBFW) *Assume % blow down (± 2%) ** Refer to design condition
LHV (Total) – Total loss Efficiency =
X 100% LHV (Total)
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Page 14 of 109
2.2.1.c. Gas Turbine Generator Conv Rad.
Flue Gas
AIR
GTG
FUEL
BH P
G
ELECTR IC
kWh x 860.1 x 3.968 Efficiency
=
X 100% LHV Fuel Gas x Flow F.G (Btu/h)
LHV Fuel Gas x Flow Fuel Gas Performance
= kWh
Efficiency of Gas Turbine also can be calculated by using heat loss method, which include heat loss of : dry flue gas H2O from combustion of H2 H2O moisture from fuel gas H2O moisture from air radiation and convection (refer to design)
2.2.1.d. Residual Gas Compressor Mechanical pressure
Fuel gas input compressor
Energy loss
work
derived
from
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Mechanical work Efficiency = Heat from fuel gas input
Mechanical Work
ZRT *= Qx x MW n
n
Pd
n-1 ) n
x ((
–1
- 1 ) / (33,000 x 0.77)
Ps
Q = Gas Flow, lb / mnt R = Gas Constant MW = Molecular weight T = inlet Temperature, oR Z = Compressibility Factor n = Polytropic Factor Pd = Discharge Pressure Ps = Suction Pressure * Refer to Pipeline Handbook Efficiency of Gas Turbine also can be calculated by using heat loss methode, which include heat loss of : dry flue gas H2O from combustion of H2 H2O moisture from fuel gas H2O moisture from air radiation and convection (refer to design)
2.2.1.e. Air compressor Electric input
Mechanical pressure
power
work
derived
from
Energy loss
Mechanical work Efficiency = Electric power input 1.4
Mechanical Work * =
Ps Q x
0.4
Pd x((
6120
Ps
O x 10.000
0.4
)1.4
- 1) x
0.8 x 0.95
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Ps = Inlet Press Kgf/ cm2 Q = Air Flow m3 / mnt R = Press ratio P2 / P1 O = Factor ( 1.0 – 1.5 ) * Refer to Energy Conservation Handbook – ECC Japan
2.2.1.f. Propane compressor
Electric input
Mechanical pressure
power
work
derived
from
Energy loss
Mechanical work Efficiency = Heat from fuel gas input
Mechanical Work * = Q x
ZRT x MW
Q = Gas Flow, lb / mnt R = Gas Constant MW = Molecular weight T = inlet Temperature, oR Z = Compressibility Factor n = Polytropic Factor Pd = Discharge Pressure Ps = Suction Pressure * Refer to Pipeline Handbook
n
Pd x ((
n–1
)
Ps
n-1 n
- 1 ) / (33,000 x 0.77)
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2.2.1.g. Gas Chiller From Gas to Gas HE Gas
H2
T1
To Propane Compressor
Gas Chiller H1 Propane
To
To Low Temperatur Separator
From Propane Acumulator
Cooling Load* = (GF x Cp g (To – Ti)) + (CF x Cpc (To – Ti)) + (f x CF x Latent Heat) Cooling Load COP Actual* = compressor motor power (actual) Cp g GF CF Cp c f
= Specific Heat gas at P & T operation = Gas Flow = Condensate Flow = Specific Heat condensate = fraction of condensate
* Refer to ASHRAE Handbook (fundamentals)
2.2.1.h. Pumps Energy loss
Electric power input
Mechanical work (capacity, total head)
Obtained from curves into data sheet
Mechanical work Efficiency = Electric power input
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Mechanical Work (Pw) *: Pw (hp) = fv.(Sg x Ht) / 3960 Sg = Specific grafity Ht = Total Head (feet) Fv = Correction factor related to viscousity
Ht (psia) = Dp – Sp Sp = Suction pressure (psia) Dp = Discharge pressure (psia) Ht (feet) = 2.31 x Ht (psia) * Refer to Pump Handbook - Karrasik, Krutzsch
2.2.1.i. Air cooler T in h
Energy loss
T out l
m, p Electric input
power
T in l
Efficiency =
T out
h
Cooling Load Electric power input
Cooling Load = Q Q = m (H) Where m : Flow rate H : Enthalpy different Fouling Factor Performance are calculated based on the value of Overall heat transfer coefficient (Uo): Uo = Q / (A Tlm) Q
: actual heat load (Q act)
A
: Heat transfer Area
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Tlm : Log Mean Temperature Different
2.2.1.j. Heat Exchanger Evaluation of heat exchanger are include the performance of heat transfer coefficient compare to design condition. If the heat transfer coefficient are lower it is could be caused by fouling or there are change in quality or quantity in the process side. VAP. OUT
VAP. OUT
VENT STEAM IN
LIQ. OUT
VAP. IN
VAP. IN
CONDENSATE OUT
a. Performance Calculation: Performance = [Heat load based on actual data calculation] [Heat load based on basic design calculation] = Q act / Q design b. Fouling Factor Performance are calculated based on the value of Overall heat transfer coefficient (Uo): Uo = Q / (A Tlm) Q
: actual heat load (Q act)
A
: Heat transfer Area
Tlm : Log Mean Temperature Different
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2.2.2. CALCULATION OF SYSTEMS 2.2.2.a. Separation System a. TSA UNIT FEED GAS
ADSORBTION COLUMN
TREATED GAS
Adsorption Rate =
(mole C6+ Feed - mole C6+ Treated)
(lbmole/lbmole)
Mole C6+ Feed TSA Regeneration Rate =
BTU
(BTU/lbmole)
(mole C6+ Feed - mole C6+ Treated) b. Membrane Unit PROCESS GAS
FEED GAS
MEMBRANE
PERMEATE GAS
Membrane separation rate = mole CO2 in Permeate Gas
(lbmole/ lbmole)
Mole CO2 in Feed Gas HC Slipped rate =
mole HC in Permeate Gas Mole HC in Feed Gas
(lbmole/ lb mole)
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2.2.2.b. Amine System a. Amine Contactor TREATED GAS LEAN AMINE
FEED GAS
AMINE CONTACTOR
RICH AMINE
Absorbtion Rate = ``mole-CO2 absorbed
(lbmole/lbmole) and (lb/lb)
Mole pure lean amine Mole Weight of pure Lean Amine are dynamic should be calculated
b. Amine Regenerator ACID GAS RICH AMINE
STEAM
AMINE REGENERATOR
CONDENSATE LEAN AMINE
Amine Regeneration Rate =
BTU(steam) CO2 removed
(BTU/lbmole -CO2)
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2.2.2.c. Dehydration System GAS
TREATED GAS
DEHYDRATION PACKAGE
GLYCOL MAKE-UP FUEL GAS CONSUMPTION GLYCOL CYCLE
MOISTURE OUT
WATER VAPOR OUT
Absorbtion Rate = lbs-H2O absorbed
(lbmole/GPM) and (Lb-H2O/Lb-Glycol)
GPM Pure Lean Glycol
Glycol Regeneration Rate =
BTU (Fuel Gas) Moisture removed
2.2.2.d. Condensate Stabilizer LP FUEL GAS
FEED LIQUID
LIGHT HC
STEAM
CONDENSATE STABILIZATION
STEAM CONDENSATE CONDENSATE
(BTU/lb –H2O)
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Yield of Stabilization = BBL Treated Condensate
(bbl/ bbl)
BBL Raw Condensate Quantity
total
of
condensate
Stabilizer Performance =
refer
to
percentage
BTU(steam)
of
feed
(BTU/ bbl)
BBL Treated Condensate flow
2.2.2.e. Depropanizer
PROPANE PRODUCT
FEED LIQUID
DEPROPANIZER
CONDENSATE PRODUCT
Yield of Stabilization =
mole Propane product
(lbmole/ lbmole)
Mole Feed HC
Deprop. Performance =
kWh(Electric) Lbmole Propane product
(kWh/ lbmol)
inlet
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III. ENERGY ASSESSMENT AT SUBAN GAS PLANT 3.1. GENERAL PLANT OPERATION AND PERFORMANCE 3.1.1. GENERAL PLANT OPERATION OF SUBAN GAS PLANT Gas from well head is delivered to CGP with flow line about 1 km length to the separation unit, HP Production Separator. Because gas produced from HP Production Separator still contain CO2, H2S and H2O in high concentration, it has to be treated by CO2/H2S Removal Package and Dehydration Unit to meet the gas delivery condition requirements. A selective Amine based on MDEA solvent shall be provided for removal of CO2 & H2S in feed gas from Gas Scrubber, to meet the sales gas specification. The system shall also include the regeneration of the MDEA solvent used to absorb H2S. Acid Gas Removal Unit is installed with capacity 700 MMSCFD (total 4 trains) Sour Gas and should be removed CO2 / H2S until meet sales gas specification (3%). Acid gas released from Acid Gas Removal unit should be routed to The treated gas scrubber Unit with enough pressure approximately 1400 psig to ensure Acid Gas have enough pressure for next processes. A Ethylene Glycol based gas dehydration unit shall be provided to dehydrate gas from amine unit to achieve the sales gas specification (5-7 Lb/SCF). EG Dehydration Unit is with capacity 700 MMSCFD (Total 4 trains). The treated gas will be compressed by GTC (Gas To Compressor) with capacity 235 MMSCFD (There are 4 GTC, each of GTC has 235 MMSCFD Capacity) to increase sales gas pressure until 1280 psig. The other part of treated gas is delivered to Fuel Gas Filter as Fuel Gas for Gas Turbine Generator (GTG),Gas Turbine Compressor or as fuel gas for the CPP gas engine equipment. The Condensate from Horizontal Separator is routed to Stabilizer Feed Drum for further separation process from carry over gas. To meet the Condensate Delivery Condition, the condensate produced is stabilized with Condensate Stabilization Units, with capacity are 44,349 Lb/hr for train 1 & 82,211 Lb/hr for train 2, and then stored in the Condensate Storage Tank with capacity is 30,000 BBL. The condensate pumps will be used to dispatch the condensate to Condensate Truck Loading. Water collect from separation unit is automatically drained to a common header and then to be processed in the produced water treatment system. Blow down system is used for over pressure protection or for reducing the CGP pressure either in emergency (ESD) or at the operator’s discretion in a shutdown and blocked condition. The blow down system shall be capable of relieving the entire CPP
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equipments from the highest possible shut-in pressure down to half times in 15 minutes. The blow down system is arranged with automatic blow down valves which is fitted at the downstream of the separation units and at the discharge of CNG Compressor to blow down through the HP Flare vent line. Localized venting of gas to atmosphere is also provided for piping and vessels via manual vents and pressure relieving devices, i.e. relief valves. Fire water will be supplied from the fire water make up pump to a Fire Water Pond. Fire water is distributed to the fire water main ring by three fire water pumps (two pumps act as main pumps, and one as jockey) in a duty standby arrangement. Foam tank and foam pump are provided to protect the condensate storage tank. The CGP shall be fully equipped with fire and gas detection system. All electric instruments shall be hard-wired to CGP Control Room and communicated to Programmable Logic Control (PLC) and Human Machine Interface (HMI) to monitor and control the process. The simple process flow of Suban field is shown with block diagram in figure 2.1 Gas to Flare 7
Acid Gas 4
T Suban Gas Well
1
T
T
2
Gas Seperation Unit
3
Amine System
T TEG Dehydration Unit
T
5
6
Sales Gas
Residual Compressor
9
8
T
10
Condensate
Condensate Stabilizer
11
Liquid water
Figure 3.1. Simple Block Diagram Gas from Inlet Separator still contains CO2 and H2O in high concentration. The gas shall be treated in purification unit before the gas is delivered to Grissik Central Gas Processing plant by Pipe line system. 3.1.2. GENERAL PLANT PERFORMANCE OF SUBAN GAS PLANT The Energy source of Suban Gas Plant actually are fuel gas from Scrubber which is consumed by GTG, GTC and Fired Heater (thermal oxidizer, amine re-boiler heater and heat medium heater). Based on 29 September 2007, the fuel gas consumption for each equipment are shown in table below;
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Table 3-1 : Fuel gas consumption
Fuel Gas to Flare 248-FQI-2131B
D
0.200 MMSCFD
248-FQI-2231B
D
1.000 MMSCFD
C
1.200 MMSCFD
225-H-102
D
0.314 MMSCFD
225-H-202
D
0.161 MMSCFD
TOTAL Fuel Gas to Heater Thermal Oxidixer
0.475 MMSCFD Amine Reb Heater 225-H-111
D
0.620 MMSCFD
225-H-211
D
0.563 MMSCFD 1.183 MMSCFD
Heat Medium Heater 257-H-101A
D
0.121 MMSCFD
257-H-101B
D
0.016 MMSCFD
257-H-201A
D
0.152 MMSCFD
257-H-201B
D
0.138 MMSCFD
C
0.428 MMSCFD
Fuel gas to GTG 247-GT-101A
-
247-GT-101B
-
247-GT-201A
C
0.900 MMSCFD
247-GT-201B
C
0.900 MMSCFD
247-GT-201C
C
0.900 MMSCFD
D
2.700 MMSCFD
242-KT-101
D
0.590 MMSCFD
242-KT-201
D
- MMSCFD
242-KT-301
D
0.730 MMSCFD
242-KT-401
D
0.700 MMSCFD
C
1.430 MMSCFD
C
6.22 MMSCFD
Fuel gas to GTC
TOTAL - 2
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C
7.42 MMSCFD
Note : D = Data ; C = Calculated
The total fuel consumption at 29 September 2007 (including fuel gas to flare) is 7.42 MMSCFD. There are two type of fuel gas used in Suban Gas Plant ie. : LP Fuel gas and HP Fuel gas. LP Fuel gas is used to fired heater and HP Fuel gas is used to GTG and GTC. The heating value (HHV) of LP Fuel gas is around 1,574 Btu/SCF and HP Fuel Gas is around 1,130 Btu/SCF. Based on the heat balance calculation of Fired Heater, GTG and GTC, the energy picture on 29 September 2007 which are includes Heat Release, Heat Absorb, Heat Loss and CO2 emission are as follows : Table 3-2 : The energy picture of Suban Gas Plant HEAT RELEASE, Btu/hr
STACK LOSS, Btu/hr
HEAT ABSORB, Btu/hr
TEMP, Deg F
CO2 Emission, lb/hr
FLARE 248-FQI-2131B
13,200,110
0
11,898,856
1,472
1,849
248-FQI-2231B
66,000,552
0
59,494,279
1,472
9,243
225-H-102
38,486,293
0
35,495,414
932
81,738
225-H-202
10,602,175
0
8,303,983
2,012
1,488
225-H-111
40,771,370
32,203,736
9,055,361
405
5,730
225-H-211
37,035,660
29,160,613
8,988,198
361
5,204
257-H-101A
8,017,576
5,448,456
2,338,395
486
1,123
257-H-101B
0
0
0
0
0
257-H-201A
10,004,765
7,479,528
2,322,751
543
1,405
257-H-201B
9,088,243
6,758,329
2,473,720
500
1,275
247-GT-101A
0
0
0
0
0
247-GT-101B
0
0
0
0
0
247-GT-201A
42,371,386
7,714,245
33,163,974
916
5,611
HEATER Thermal Oxidizer
Amine Reboiler H-M Heater
Heat Medium Heater
GTG
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247-GT-201B
42,371,386
7,721,419
29,310,275
921
5,611
247-GT-201C
42,371,386
7,702,911
29,397,944
925
5,611
242-K-101
28,157,031
4,816,837
21,555,786
1,213
1,668
242-K-201
0
0
0
0
0
242-K-301
34,800,050
7,277,193
22,755,271
1,261
2,064
242-K-401
33,379,354
6,924,878
21,806,787
1,237
1,979
123,208,143 298,360,993
689
131,598
GTC
TOTAL
456,657,336
Plant Performance : The production rate at 29 September 2007 is 94,023 BOE which include 517 MMSCFD of sales gas (note : 1 SCF = 6000 BOE) and 7,823 barrel of condensate, and total heat released including flare gas is 456,657,336 Btu/hr. The performance of Suban Gas Plant as shown in table below : Table 3-3 : Suban Gas Plant performance
PRODUCTION RATE Sales Gas = =
517.20 MMSCFD 86,200.00 BOE
Condensate =
7,823.00 BOE
Total Prod =>
94,023.00 BOE
ENERGY CONSUME Excluding Flare Including Flare ENERGY INTENSITY Excluding Flare Including Flare
377,456,674.27 456,657,336.12 Btu/hr
4,014.51 Btu/BOE 4,856.87 Btu/BOE
It shown that the energy consumption to produce one BOE (= Energy Intensity) at Suban Gas Plant is 4,014.51 Btu/BOE (Excluding Flare) or 4,856 Btu/BOE (including flare) . (Note : No design data to compare the Actual Energy Intensity).
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This condition can not compare with another gas plant, because every plant have its own characteristic. The important thing is how to reduce energy consumption based on its own characteristic.
3.2 PERFORMANCE EVALUATION EACH SYSTEM 3.2.1 SEPARATION & COOLER SYSTEM A. DESCRIPTION Gas from manifold enters the Inlet Separator which will separate gas from the bulk liquid. The separator are designed for gas flow 160 MMSCFD (for train 1,2) and 214 MMSCFD (for train 3,4), whereas liquid flow are designed about 1973 gallon/min ( for train 1,2) and 2640 gallon/min (for train 3,4) . Production Separator will be normally operated at pressure 1188 psig and temperature 240 °F. The Inlet Separator is a three phase separator to provide primary gas-condensatewater separation. This is to ensure that no significant carry-over/under of the respective phases. B. PERFORMANCE Main equipment of Separation and cooler system are include : Inlet Cooler 215-E101A/B, 215-E-201A/B, 215-E-401A/B and 215-E-301A/B. The performance of main equipment are as follows. Table 3-4 : Performance of Inlet Cooler
215-E-101
215-E-201
215-E-301
215-E-401
DESIGN
Temp inlet, F
220.00
218.00
220.00
220.00
240.00
Temp outlet, F
110.00
110.00
110.00
110.00
115.00
Flowrate, lb/hr
323,297
323,297
486,956
486,956
476,174
Temp inlet, F
93.20
93.20
93.20
93.20
95.00
Temp outlet, F
113.00
113.00
114.00
114.00
131.60
Delta T LMTD
45.96
45.96
46.54
46.54
52.30
HEAT DUTY, MMBtu/hr
28.37
28.37
43.04
43.04
50.01
HEAT TRANSFER RATE, BTU/HR.FT2.F
4.46
4.46
3.08
3.08
5.09
INLET GAS COOLER
AIR COOLANT
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ELECTRIC CONSUMPTION, KW
13.13
13.13
13.13
13.13
16.41
ACTUAL FAN OPERATED
4.00
4.00
4.00
4.00
4.00
CALCULATE FAN OPERATED
3.04
3.04
3.44
3.44
4.00
The above table shows that the actual heat duty of each inlet cooler are less than design. It means that the actual cooling rate needs less energy than design. The heat duty on Train #1 and #2 are operated at 60% of design. The heat transfer rates of exchangers are closed to the design. Based on actual condition, the performance of cooler is still in good condition. Losses at inlet cooler are described from cooler outlet temperature. If the outlet temperature higher than the design outlet temperature, it means the cooling rate is not good. At this case, the exchangers are still in good condition. 3.2.2 AMINE SYSTEM A. DESCRIPTION The feed gas from Inlet Separator contains CO2 5.42% by mole and small of H2S content. A typical feed condition is 114 oF and 1163 psia; The products specifications is designed for the CO2 content is 3.4 % by mole respectively. The acid gas removal package uses activated methyl-di ethanolamine (MDEA) to remove the acid gases (H2S & CO2) by means of counter-current mass transfer in an Amine Contactor unit. The gas from the inlet separator will be fed to the Acid Gas Removal Package. As the inlet gas is a saturated gas stream, there is a possibility of hydrocarbon and water condensation prior to inlet of the amine contactor. To minimise liquid carry-over to the system, a Horizontal filter unit is provided. The horizontal filter unit will have level control drain-off valves, both on the upstream and downstream of the filter element, whereby the liquid is sent to the flare system for disposal. The liquid free gas from the Horizontal filter is then fed to the Amine Contactor, whereby the gas is in contact with lean aqueous MDEA solution (amine). The enhanced solubility of the acid gas in lean amine would soluble the acid gas component, thus stripping it of H2S and CO2. The rich amine from the contactors flows to the rich amine flash drums. The rich amine flows under level/flow control through the lean/rich amine exchangers where it is heated to about 206 oF by heat exchange with the hot lean amine from the two regenerators. The rich amine feeds the regenerator above the stripping section which contains stainless steel structured packing. CO2 and H2S are stripped from the rich solution by heat produced in the regenerator re-boilers.
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B. PERFORMANCE Main equipment of Amine System are includes : Amine Heat Medium Heater (225-H-111; 225-H-211); Amine Reg. Reboiler (225-E-102 A/B, 225-E-202 A/B); Treated Gas Cooler (225-E-105, 225-E -205, 225-E -305, 225-E -405), Amine Charge Pump (225-P-102A/B/C), Amine Booster Pump (225-P-101A/B/C) and Amine Heat Medium Circ. Pump (225-P-111A/B/C, 211A/B/C). The performance of main equipment of Amine System are as follows. Amine Heat Medium Heater : Table 3-5 : Performance of Amine Heat Medium Heater 225-H-111
225-H-211
DESIGN
0.62
0.56
1.13
404.60
361.40
412.00
O2, %
6.50
9.20
3.00
Excess Air, %
41.00
83.15
15.27
2,285,233
2,004,973
2,910,000
T in, F
257
257
285
T out, F
270
270
305
P in, Psi
280
280
285
P out, Psi
270
270
274
Heat absorption (LHV), MMBtu/hr
31.81
28.70
57.98
Heat absorption (HHV), MMBtu/hr
32.20
28.94
58.12
Efficiency (LHV), %
85.80
84.87
89.11
Efficiency (HHV), %
78.95
78.06
81.18
5,730
5,203
10,609
FUEL, Flow, MMSCFD FLUE GAS T out, F
HOT WATER lb/hr
PERFORMANCE
CO2 EMISSION CO2 Emission from fuel gas, lb/hr
The heat duty of Amine H-M Heater was only 55 % and 50 % load compare to design condition.
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The efficiency by using heat loss method are calculated based on the flue gas composition and temperature measurement by using portable analyzer and thermometer. No meter of temperature and O2 analyzer in flue gas line. The flue gas temperature at actual condition is lower than design condition but the excess air is too high and the operating load is too low. The efficiency at actual condition is around 85 % compare to design condition which is 89 %. This efficiency is low compare to design condition, it is caused by higher excess air and lower operating load. Amine Regenerator Reboiler: Table 3-6 : Performance of Amine Regenerator Reboiler
225-E-102A/B
225-E-202A/B
DESIGN
Pressure, psig
280.00
8.70
235.00
Temp. inlet (F)
275.00
278
305.00
Temp. outlet (F)
250.00
250
285.00
1,025,912
894,957
1,412,550
Temp. inlet Regenerator, F
212.00
205
249.1
Temp. outlet Regenerator, F
220.00
240
254.3
Delta T LMTD
45.98
41.40
42.88
26,313,323
25,711,215
29,084,405
85
93
101
HEAT MEDIUM SIDE (TUBE)
Flowrate Heat Medium, Lb/hr AMINE SIDE (SHELL)
HEAT DUTY, Btu/hr HEAT TRANSFER RATE SERVICE, 2 BTU/HR.FT .degF
The above table shows that the heat duty operated closed to the design. The difference between actual heat duty and design only 10%. The operated temperature higher than design value. The performance of heat exchanger can be evaluated from the value of overall heat transfer rate (U). The U at actual condition is 85 BTU/(Hr/Ft2.F) and 93 BTU/(Hr/Ft2.F) compare to design value which is 101 BTU/(Hr/Ft2.F..
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Treated Gas Cooler : Table 3-7 : Performance of Treated Gas Cooler 225-E-105
225-E-205
DESIGN
Pressure,psig
1206
1202
1162
Temp inlet, F
147.90
152.00
139.80
Temp outlet, F
120.70
125.70
120.00
Flowrateof Acid gas, MMSCFD
138.92
119.56
151.80
Temp inlet, F
92.00
92.00
95.00
Temp outlet, F
110.00
112.00
118.40
Delta T LMTD
33.09
36.76
26.50
4,622,698
3,873,942
4,300,000
56.79
55.61
59.68
2
2
2
CALCULATE FAN OPERATED
2.1
1.8
2.0
HEAT TRANSFER RATE, BTU/HR.FT2.F
3.9
3.0
5.2
225-E-305
225-E-405
DESIGN
Pressure,psig
1206
OFF
1162
Temp inlet, F
147.90
OFF
139.80
Temp outlet, F
126.50
OFF
120.00
Flowrateof Acid gas, MMSCFD
204.82
OFF
203.40
Temp inlet, F
92.00
OFF
95.00
Temp outlet, F
110.00
OFF
118.40
Delta T LMTD
33.09
OFF
26.5/23
5,346,317
OFF
5,810,000
WATER+ACID GAS
AIR COOLANT
HEAT DUTY, Btu/hr ELECTRIC CONSUMPTION, KW ACTUAL FAN OPERATED
WATER+ACID GAS
AIR COOLANT
HEAT DUTY, Btu/hr
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59.15
OFF
59.68
2
OFF
2
CALCULATE FAN OPERATED
1.9
OFF
2.0
HEAT TRANSFER RATE, BTU/HR.FT2.F
4.5
OFF
5.4
ACTUAL FAN OPERATED
The above table shows that the actual heat duty closed to the design. The difference between actual and design only +/- 10%. Electric power consumption for motor fan drivers also close to design with deviance not more than 7%. The fan running at actual condition also same as design, each exchanger have 2 (two) fans running. This indicates that the process is in good condition. Temperatures of gas outlet from these exchangers all meet the specification process condition, 120.7 and 125.7 deg F for train#1 and #2, and 126 deg F for train#3 refer to the design is 120 and 203.4 deg F respectively. The performance of heat exchanger can be evaluated from the value of overall heat transfer rate (U). The U at operating condition give value of 3.9 and 3.0 BTU/(Hr/Ft2.F) for train#1 and train#2 and 4.5 BTU/(Hr/Ft2.F) for train#3. The design value is 5.2 and 5.4 BTU/(Hr/Ft2.F). Regenerator Reflux Condenser : Table 3-8 : Performance of Regenerator Reflux Condenser 225-E-101
225-E-201
DESIGN
Pressure,psig
11.9
12
26.9
Temp inlet, F
194.40
226.4
205.00
Temp outlet, F
135.60
120.5
120.00
5.50
7.3
8.76
Temp inlet, F
92.00
92
92.00
Temp outlet, F
140.00
145
144.00
Delta T LMTD
48.80
50.41
48.60
9,259,749
13,234,590
16,824,662
17.67
40.04
44.00
2
4
4
CALCULATE FAN OPERATED
2.2
3.1
4.0
HEAT TRANSFER RATE,
1.9
2.7
3.0
WATER+ACID GAS
Flowrateof Acid gas, MMSCFD AIR COOLANT
HEAT DUTY, Btu/hr ELECTRIC CONSUMPTION, KW ACTUAL FAN OPERATED
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BTU/HR.FT2.F
The above table shows that regenerator reflux condenser is operated at 55% load for 225-E-101 and 78% load for 225-E-201 compare to design condition. This caused by the flow rate of acid gas are 62% and 83% compare to design condition. Actual fan operated for the cooler 225-E-101 is 2 fans running, but the calculated fan should be operated is 3 fans (2.2). This causes the temperature of the outlet of cooler is higher than the design. Design value state the temperature is 120 deg F, but this cooler operated at 135 deg F. The outlet temperature of cooler 225-E-201 is meet to the design value. The U (overall heat transfer rate) at actual condition is 1.9 and 2.7 BTU/(Hr/Ft2.F) for 225-E-101 and 225-E-201 compare to design is 3.0 BTU/(Hr/Ft2.F). Lean Amine Cooler : Table 3-9 : Performance of Lean Amine Cooler
225-E-103
225-E-203
DESIGN
Pressure, psig
135.00
135.00
129.43
Temp inlet, F
180.00
180
182.90
Temp outlet, F
130.00
130
125.00
Temp inlet, F
94.00
94
95.00
Temp outlet, F
135.00
134
137.20
Delta T LMTD
40.33
40.80
37.30
HEAT DUTY, Btu/hr
16,784,037
16,254,308
31,537,959
ELECTRIC CONSUMPTION, KW
35.35
35.35
76.00
ACTUAL FAN OPERATED
2.00
2.00
4.00
CALCULATE FAN OPERATED
2.1
2.1
4.0
HEAT TRANSFER RATE, BTU/(HR.Ft2.degF)
1.6
1.5
1.8
LEAN AMINE SIDE
AIR COOLANT SIDE
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The above table shows that the actual heat duty of 225-E-103 and 225-E-203 are rated at 50% compare to the design. This caused by the flow rate of lean amine only about 50% - 60% from design capacity. The flow rate of lean amine affects to the power required of fan cooler driver. The actual operated fans for 225-E-103 and 225-E-203 are 2 fans compare to 4 fans for design. This condition affects the performance of cooler, especially with heat transfer rate. The value of U (overall heat transfer rate) at actual condition is 1.6 BTU/(Hr/Ft2.F) for 225-E-103 and 1.5 for 225-E-203 compare to design 1.8 BTU/(Hr/Ft2.. This difference indicated that the performance of coolers are still have good performance. Rich-Lean Amine Exchanger : Table 3-10 : Performance of Rich-Lean Amine Exchanger
225-E-104A-B
225-E-204A-B
DESIGN
Pressure, psig
90.00
100.00
100.00
Temp inlet, F
105.00
105.00
138.20
Temp outlet, F
190.00
210.00
210.20
Flowrate of Rich Amine, USGPM
458.20
483.40
1,138.90
Temp inlet, F
250.00
250.00
253.20
Temp outlet, F
210.00
210.00
182.30
Delta T LMTD
80.41
67.35
43.55
16,403,302
20,960,808
39,616,136
N/A
N/A
N/A
RICH AMINE SIDE
LEAN AMINE SIDE
HEAT DUTY, Btu/hr HEAT TRANSFER RATE, BTU/(Hr/Ft2.F)
The flow rate of fluid in Rich-lean amine exchanger is about 40% from design capacity. This will affect the heat load for these exchangers at 40% for 225-E-103 and 50% for 225-E-203. LMTD between hot fluid and cold fluid are higher than the design specification. This case will affect the heat transfer rate for these exchangers. The temperature inlet of Rich amine is lower compare to the design value. This is indicate the amine contacting process in the field running on lower temperature than the design specification.
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Lean Amine Charge Pump : Table 3-11 : Performance of Lean Amine Charge Pump
DESCRIPTION
UNIT
225-P-102A
225-P-102B
225-P-102C
Design
value
value
value
value
specific gravity
1.05
1.05
OFF
1.00
Temperature
F
137.00
137.00
OFF
125.00
suction pressure
psia
111.00
111.00
OFF
N/A
discharge pressure
psia
1550.00
1550.00
OFF
N/A
flow
GPM
265.00
265.00
OFF
1165.00
Total head
ft
3180.05
3180.05
OFF
2550.00
Electric motor power
HP
575.00
575.00
OFF
1000.00
Mechanical work
HP
227.34
227.34
OFF
766.69
Efficiency
%
39.54
39.54
OFF
76.67
Two Amine Charge pumps were running at 265 GPM each, and had efficiency of 39.54%. This efficiency is quite low compare with 76.67% efficiency at design condition. This is due to very low flow rate they handled. The 76.67% efficiency can be achieved at 1165 GPM. The sum of fluid flow rate for each pump (530 GPM) is still far below the design flow rate for one pump. Higher efficiency could be achieved should the fluid flowing is handled by one pump only. Amine Reboiler H/M Circulation Pump : Table 3-12 : Performance of Amine Reboiler H/M Circulation Pump
DESCRIPTION
UNIT
specific gravity
225-P111A
225-P111B
225-P211A
225-P211B
Design
1.00
1.00
1.00
1.00
1.00
Temperature
F
137.00
137.00
137.00
137.00
285.00
suction pressure
psia
205.70
205.70
205.70
205.70
N/A
discharge pressure
psia
294.70
294.70
294.70
294.70
N/A
flow
GPM
2211.00
2186.00
1911.00
1911.00
3044.00
Total head
ft
205.59
205.59
205.59
205.59
180.00
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Electric motor power
HP
168.00
168.00
152.00
152.00
190.00
Mechanical work
HP
117.31
115.99
101.40
101.40
141.41
KW
87.52
86.53
75.64
75.64
105.49
%
69.83
69.04
66.71
66.71
74.43
Efficiency
Two of the three pumps were working to feed Amine re-boiler medium heater, so four pumps worked to serve two Amine re-boiler medium heater. Each circ.-pump (P-111 A/B) worked at 2211 and 2186 GPM, with 69% efficiency and P-211 A/B worked at 1911 GPM, with 66% efficiency. All pumps are operated close to design efficiency. Lean Amine Booster Pump : Table 3-13 : Performance of Lean Amine Booster Pump
DESCRIPTION
UNIT
225-P-101A
225-P-101B
1.05
1.05
1.00
137.00
137.00
125.00
specific gravity
Design
Temperature
F
suction pressure
psia
16.70
16.70
N/A
discharge pressure
psia
131.70
131.70
N/A
flow
GPM
225.00
225.00
1430.00
Total head
ft
115.00
115.00
244.00
Electric motor power
HP
70.00
70.00
122.00
Mechanical work
HP
15.43
15.43
90.05
Efficiency
%
22.04
22.04
73.81
The worst case was found at Amine booster pumps, the efficiency of P-101-A/B is only 22 %. The production process utilized two of the three pumps to support Lean amine charge pumps. Each of these booster pumps pumping out fluid at 225 GPM. The sum of fluid flow rate (450 GPM) is still far below the design flow rate for one pump. Higher efficiency could be achieved should the fluid flowing is handled by one pump only. 3.2.3 CONDENSATE STABILIZING SYSTEM A. DESCRIPTION Hydrocarbon liquid from inlet separator and LTS are sent to the stabilizer feed drum. Gas from the feed drum is sent under back pressure control to the low pressure fuel gas system.
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The hydrocarbon liquid from the feed drum is fed under level control to the top tray of the condensate stabilizer. The stabiliser reboiler is a kettle type shell and tube exchanger utilizing hot water from Medium Heater at operation. The condensate product from the stabilizer is sent via the HC condensate cooler bundle in the refrigerant condenser air cooled exchanger frame and a kettle type hydrocarbon condenstae cooler by propane refrigerant, gas blanketed, condensate storage tank. B. PERFORMANCE Main equipment of Condensate Stabilizing system are includes : Heat medium heater 257-H-101A/B, 257-H-201A/B; Stabilizer Re-boiler 235-E-101A/B, 235-E-201A/B; Condensate Cooler 235-E-102, 235-E-102 Heat Medium Heater : Table 3-14 : Performance of Heat Medium Heater 257-H-101A
DESIGN
0.12
0.10
T out, F
511.20
629.00
O2, %
13.90
3.00
Excess Air, %
179.07
15.27
, lb/hr
106,647.53
110,000.00
T in, F
310.00
316.60
T out, F
350.00
360.00
P in, Psi
N/A
200.00
P out, Psi
N/A
200.00
Heat absorption (LHV), MMBtu/hr
5.34
4.76
Heat absorption (HHV), MMBtu/hr
5.45
4.76
Efficiency (LHV), %
73.57
83.00
Efficiency (HHV), %
67.94
75.49
1,122.86
937.53
FUEL, Flow, MMSCFD FLUE GAS
HOT WATER
PERFORMANCE
CO2 EMISSION CO2 Emission from fuel gas, lb/hr
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Table 3-14 : Performance of Heat Medium Heater 257-H-201A
257-H-201B
DESIGN
FUEL, Flow, MMSCFD
0.15
0.14
0.17
T out, F
568.80
525.60
629.00
O2, %
8.50
10.20
3.00
Excess Air, %
62.20
86.38
15.27
, lb/hr
228,820.95
180,110.31
164,900.00
T in, F
300.00
300.00
316.6
T out, F
330.00
330.00
360
P in, Psi
N/A
225.00
227.5
P out, Psi
N/A
210.00
200
Heat absorption (LHV), MMBtu/hr
7.38
6.66
7.94
Heat absorption (HHV), MMBtu/hr
7.48
6.76
8.00
Efficiency (LHV), %
81.18
80.73
84.00
Efficiency (HHV), %
74.76
74.36
76.77
1,404.86
1,275.47
1,552.85
FLUE GAS
HOT WATER
PERFORMANCE
CO2 EMISSION CO2 Emission from fuel gas, lb/hr
The above table shows that H-101 A, H-201 A and H-201-B are operated close to design condition. The efficiency by using heat loss method are calculated based on the fuel gas heating value, flue gas composition and temperature measurement by using flue gas analyzer. Flue gas temperature is lower than design condition but the excess air is very high. Calculated Efficiency of 257-101-A is 73 % compare to design is 84 % and the efficiency of 257-201-A/B is around 81 % compare to design is 84 %. The lower efficiency is caused by higher excess air of the heater.
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Condensate Stabilizer Re boiler : Table 3-15 : Performance Condensate Stabilizer Re-boiler
235-E-101
235-E-201
180.00
200.00
DESIGN
HEAT MEDIUM SIDE (SHELL) Pressure, psig
200.00
Temp. inlet, F
350.00
335.00
350.00
Temp. outlet, F
295.00
300.00
310.00
Flowrate (Heat medium), Lb/hr
39,139.19
57,038.28
Temp Condensate to reboiler, F
278.00
278.00
298.00
Delta T LMTD
34.78
32.93
45.36
HEAT DUTY, Btu/hr
2,214,754
2,053,347
HEAT TRANSFER RATE, (BTU/Hr.Ft2.F)
39.14
38.32
n/a
Hydrocarbon Side
3,000,000 40.65
The above table shows that actual condition of heat duty of 235-E-201 and 235-E-101 is lower than design. The reboiler of 235-E-201 have capacity higher than 235-E-101 but the heat transfer rate are close to design. Condensate Cooler : Table 3-16 : Performance Condensate Cooler 235-E-102
235-E-202
DESIGN
Temp inlet, F
288.00
288
304.30
Temp outlet, F
106.60
106.5
120.00
Flowrate, GPM
101.89
193.4
287
Temp inlet, F
92.00
92
95.00
Temp outlet, F
136.00
136
139.90
Delta T LMTD
58.65
58.52
74.00
1,976,054
3,752,578
7,841,737
CONDENSATE
AIR COOLANT:
HEAT DUTY, Btu/hr
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HEAT TRANSFER RATE, BTU/HR.FT2.F
1.11
2.12
2.36
ELECTRIC CONSUMPTION **), KW
8.83
9.42
11.00
The above table shows that the condensate cooler have heat duty only 25% for 235E-102 and 48% for 235-E-202 refer to the design value. This caused by the flow rate of condensate, and LMTD. The flow rate for 235-E-102 is 35% and 235-E-202 is only 67% refer to the design. LMTD value for cooler 235-E-102 and 235-E-202 are 80% from LMTD design. This affect the value of heat load (Q) of coolers, because the heat load is straight forward with condensate flow rate and LMTD. The overall heat transfer rate (U) at actual condition is 1.11 BTU/(Hr/Ft2.F) for 235-E102 and 2.12 BTU/(Hr/Ft2.F for 235-E-202 compare to the design is 2.36 2 BTU/(Hr/Ft .F). 3.2.4 DEW POINT CONTROL AND REFRIGERATION SYSTEM A. DESCRIPTION The propane refrigerant gas from gas chiller via suction scrubber enter the 1st stage propane compressor. The propane refrigerant gas from the 1st compressor discharge and from the economizer goes to the propane compressor 2nd stage than the discharge of 2nd stage goes to the condenser cooler and enter to the accumulator. Propane refrigerant from the accumulator goes to the economizer (flushing). Propane gas from the economizer enter the suction of 2nd stage compressor and the propane refrigerant enter the gas chiller via propane subcooler. The design flowrate of the 1st stage propane compressor is 38,200 lbs/hr and the 2nd stage of propane compressor is 52,800 lbs/hr. There are 3 propane compressor driven by electric motor 1300 KW each and via refrigerant header supply refrigerant for 4 gas chillers (1 gas chiller for 1 train). At the actual condition only 2 compressor are in operation. B. PERFORMANCE Main equipment at Refrigeration system are includes propane condenser, propane compressor and gas chiller. Propane Condenser : Table – 3.17 : Performance of Propane Condenser 230-E-104 PROPANE :
DESIGN
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Pressure, psig
250
265
Temp inlet, F
140.00
180.00
Temp outlet, F
119.00
121.00
Flowrate, MMSCFD (gas)
30.00
32.90
Temp inlet, F
92.00
95.00
Temp outlet *), F
112.00
117.50
Delta T LMTD
27.50
26.30
HEAT DUTY, Btu/hr
19,151,470
25,387,806
ELECTRIC CONSUMPTION **), KW
17.67
22.00
HEAT TRANSFER RATE, BTU/HR.FT2.F
2.59
3.29
AIR COOLANT:
The above table shows that actual condition of heat duty of 230-E-104 is 75% compare to design. The heat duty impact on the power required for fan driver which is 80% electric consumption respectively. The U value (overall heat transfer rate) at actual condition is 2.59 BTU/(Hr/Ft2.F) and 3.29 BTU/(Hr/Ft2.F for the design value. Entirely, the performance of propane condenser is operated at good condition. Propane Compressor: Table – 3.18 : Performance of Propane Compressor UNITS
PROPANE FLOW ST. 1
DESIGN
K 101 A
30,669.25
25,861.64
(calculated)
(calculated)
42,446.24
35,792.51
(calculated)
(calculated)
24.50
24.00
24.00
ABL.DISCHARGE PRESS ST 1
101.00
100.00
100.00
ABSL DICHARGE PRESSURE ST. 2
265.00
260.00
260.00
TOTAL POWER REQUIRED
1,214.78
966.64
815.11
ACTUAL POWER
1,300.00
1,110.00
936.00
PROPANE FLOW ST. 2 ABSL SUCTION PRESSURE ST.1
COP
38,160.00
K 101 C
52,800.00
1.89
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The above table shows that the propane compressor operated at 70-80 % load. The calculated propane flow of stage-1 K-101 A and K-101 C are 30,669 lb/hr and 25,861 lb/hr with the actual power are 1110 KW and 936 KW . The design propane flow of stage-1 is 38,160 lb/hr with the power is 1,300 KW. It means that the propane compressor is still operated at normal conditions. The design COP of the propane compressor is 1.89. COP at actual condition can not be calculated accurately because no meter for propane flow. Gas Chiller: Table – 3.19 : Performance of gas chiller UNITS
DESIGN
GAS CHILLER (230-E102/201/302/402)
GAS INTAKE TEMP.AT EVAP.
DEG F
1.00
16.00
GAS OUTPUT TEMP.AT EVAP.
DEG F
(10.00)
5.00
SALES GAS FLOW
MMCFD
300.00
533.00
BBL/D
4,000.00
3,000.00
16.52
11.80
2,600.00
1,930.00
1.86
1.79
CONDENSATE FLOW HEAT RELEASE
MMBtu/hr
TOTAL POWER
KW
C.O.P
The above table shows the cooling load of gas chiller is 71 % load and two of propane compressor are operated to handle the refrigeration system. Performance of each gas chiller can not be calculated, because two propane compressors serve four gas chillers simultaneously. However total performance still can be calculated. The operating condition of four gas chiller almost similar (T gas inlet = 16 F , T out gas = 5 F). Total COP of gas chiller is 1.79. It’s still close to design condition. 3.2.5 GAS COMPRESSION A. DESCRIPTION The pressure of treated gas after Amine System and Refrigeration System is decrease lower than 1000 psig. To meet the pressure requirement of sales gas it needs to compress sales gas by using Residual Gas Compressor. There are 4 gas compressor 2 x 235 MMSCFD and 2 x 300 MMSCFD driven by gas turbine generator. At the actual condition only 3 GTC in operation and 1 GTC standby
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B. PERFORMANCE Main equipment at Gas Compression System are 242-K-101, 242-K-102, 242-K-301 and 242-K-401, Gas Compressor : Table – 3.20 : Performance of Gas Compressor UNITS
DESIGN
242-K-301
242-K-401
SALES GAS FLOW ( Q )
MMSCFD
235.00
206.00
206.00
SUCTION PRESSURE
PSIA
965.00
915.00
915.00
DISCHARGE PRESSURE
PSIA
1,295.00
1,130.00
1,115.00
FUEL CONSUMPTION
MMBtu
36.01
28.06
26.36
POWE REQUIRE (POLYTROPIC)
HP
4,537.09
2,835.13
2,651.33
ENERGY INTENSITY
Btu/HP
7,936.81
9,896.28
9,940.95
DESIGN SALES GAS FLOW ( Q )
MMSCFD
SUCTION PRESSURE
242-K-101
10,905.10
150.00
PSIA
955.00
910.00
DISCHARGE PRESSURE
PSIA
1,215.00
1,110.00
FUEL CONSUMPTION
MMBtu
40.92
20.19
POWE REQUIRE (POLYTROPIC)
HP
4,653.97
1,940.43
ENERGY INTENSITY
Btu/HP
8,792.49
10,406.28
242-K-201 OFF
The above table shows that the compressor are operated at 80 % load compare to design condition. The Energy Intensity (Btu/HP) of 242-K-101, 242-K-301 and 242-K-401 are higher compare to design value. This condition is caused by the lower operating load of compressors. To know the performance of compressor, it should be compare with design performance of gas turbine compressor (see table below).
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Gas Turbine : Table – 3.21 : Performance of Gas Turbine Compressor 29-Sep-07 242-KT-101 A
DESIGN
242-KT-201
242-KT-101 /201
TURBINE Fuel gas : flow, MMSCFD
0.59
OFF
1.02
Temperature, C
1,213
OFF
1,160
O2, %
14
OFF
14
Excess Air, %
191
OFF
185
Eff, %
19
OFF
25
Btu/HP
13,256
OFF
10,115
Power Required, KW
1,447
OFF
3,471
, HP
1,940
OFF
4,653
Flue gas :
B
COMPRESSOR
29-Sep-07 242-KT-301 A
DESIGN 242-KT-401
242-KT-301/ 401
TURBINE Fuel gas : flow, MMSCFD
0.73
0.70
1.05
Temperature, C
1,261
1,237
1,175
O2, %
14
14
14
Excess Air, %
168
174
174
Eff, %
23
23
27
Btu/HP
10,946
11,225
9,401
Power Required, KW
2,115
1,978
3,409
, HP
2,835
2,651
4,570
Flue gas :
B
COMPRESSOR
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In the daily operation, the gas turbines efficiency is around 23 %, these efficiency is less than the design condition (27%). Based on the design performance below, the performance of gas turbine at low load are close to design figure. DESIGN PERFORMANCE OF GTC K-301/401 POWER, HP BTU/KWH
5,000.00
4,000.00
3,000.00
2,000.00
1,000.00
9,400.00
10,000.00
11,000.00
12,500.00
17,000.00
DESIGN PERFORMANCE OF GTC K-101/201 POWER, HP BTU/KWH
5,000.00
4,000.00
3,000.00
2,000.00
1,000.00
10,100.00
10,700.00
11,600.00
13,200.0 0
17,000.00
3.2.6 GAS TURBINE GENERATOR A. DESCRIPTION Electrical power Generator driven by Gas turbine generator, with the gas supplied from HP (high pressure) fuel gas system. There are 2 GTGs each 1173 KW from Suban phase-1 and 3 GTGs each 5820 KW from Suban phase-2. The Generator specification are 5820 KW of power, 6600 volt, freq 50 Hz, cos Q 0.85. The large motors (lean amine charge pump, Amne reboiler HM Pump, propane compressor) are supplied by 6600 volt and the other motors using 400 volts. B. PERFORMANCE The main equipment of gas turbine generator are 247-GTG-101A/B and 247GTG-201A/B/C The performance of GTG are as follow : Table – 3.22 : Performance of GTG 29-Sep-07 247-GT-201A
247-GT201B
DESIGN 247-GT201C
247-GT-201A
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TURBINE Fuel gas : flow, MMSCFD
0.90
0.9
0.90
1.62
Temperature, F
916
921
925
946
O2, %
16
16
16
15
Excess Air, %
312
309
308
243
Turbine Eff, %
18.04
18.04
18.01
30
Btu/kwh
16,925
16,926
16,950
11,336
Flow, lb/hr
5,611
5,611
5,611
4,446
Power Output, KW
2,146
2,102
2,178
5,821
PF
0.83
0.83
0.84
Voltage, V
6,600
6,600
6,600
6,600
Frequency, Hz
50
50
50
50
Flue gas :
CO2 emission : GENERATOR 0.83
GTGs are operated less than 40 % load each, total load is around 6,426 KW. This load actually can be handle by two GTGs with 55 % load each. If any disturbance occurs, the load shading system will shut off un-priority load, so system black out can be avoided. The low load of GTG caused low efficiency of gas turbine. The stack temperature of GTG are close to design condition but the calculated efficiency is only 18 % compare to design which is 30 %. The decreasing efficiency is caused by lower operating load which will increased radiation and convection loss. Compare to the design performance of gas turbine generator (table below) , the performance GTG at low load are still in good condition Table – 3.23 : Design Performance of GTG DESIGN POWER BTU/KWH
PERFORMANCE OF GTG 5,800 11,340
5,000 11,800
4,000 12,600
3,000 14,300
2,000 17,200
1,000 25,000
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3.2.7 AIR COMPRESSOR A. DESCRIPTION Instrument and utility air are supplied by the 1x340 scfm and 1x140 scfm screw type compressor. The compressed air is filtered and then dried in heatless adsorption type dries which are on automatic regeneration cycles. The instrument air compressor packages are provided with local electronic control panels. The instrument air receiver is normally operated between 110 and 120 psig. B. PERFORMANCE There are four compressors Atlas Copco GA 37 x 2 and GA 75 x 2 with design capacity is 960 SCFM, the duty of each equipment are as follows, The performance of air compressor are as follows : Table 3-24 : Performance of Air Compressor 251-A-101A (ATLAS COPCO GA 75)
DESIGN
ACTUAL
POWER
72.60
45.93
COMPRESS AIR FLOW
340.00
266.66
0.20
0.20
ACTUAL PERFORMANCE
251-A-101 B (ATLAS COPCO GA 37) DESIGN
ACTUAL
POWER
44.00
28.27
COMPRESS AIR FLOW
140.00
129.90
0.33
0.25
ACTUAL PERFORMANCE
The above table shows that the compressor is operated at low load. Actual power of 251-A-101 A is 45.93 KW compare to design 72.6 KW and 251-A-101 B is 28.27 KW compare to design 44 KW. Actual performance of air compressor calculated by : (Actual power / Qs x ((Pd/Ps)^0.2857 – 1))
Note : Qs = air flow
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3.2.8 ELECTRICAL MAP SUBAN GAS PLANT Electrical map is derived from single line diagram, and intend to get a closer and clear point of view to one that need brief description on power consumption at each process. This map is made simple as possible so, it doesn't show how the electric system is distributed. Emphasize is given to voltage, and power required for each equipment. Note that the power mentioned below is the power in normal design condition. A. Inlet Gas System
400 V 215-EM-301/401/A/B 1-2 Inlet cooler fan 22 KW x8
B. Amine System 6.6 KV
225-P-102A/B/C Lean Amine Charge pump A/B/C
225-P-111A/B/C Amine reboiler H/M circ pump A/B/C
1130 HP x3
225-P-211A/B/C Amine reboiler H/M circ pump A/B/C
185 HP x3
185 HP x3
400 V 225-P-102A/B/C Lean Amine booster pump A/B/C
225-PM-103A/B Regenerator reflux pump A/B
225-PM-203A/B Regenerator reflux pump A/B
112 HP x3
3.73 HP x2
3.73 HP x2
225-EM-103A/B/C/D Lean Amine cooler fan 19 KW x4
225-EM-203A/B/C/D 225-EM-105/205/305/405 A Lean Amine cooler fan Treated gas cooler fan 19 KW x4
225-EM-101/201 A/B/C/D 225-PM-105 Regenerator reflux condenser fan Amine transfer pump 11 KW x8
14.7 HP
19 KW x4
225-EM-105/205/305/405 B Treated gas cooler fan 19 KW x4
225-PM-104 Amine sump pump 14.7 HP
C. Dehydration system 400 V 229-PM-302/402/A/B Glycol Injection pump 26.8 HP
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D. Propane Compressor System 6.6 KV
230-KM-101 A/B/C Propane compressor A/B/C 1306 KW x3
400 V
230-EM-104 A/B/C/D 1-2 Propane condenser fan A-D
230-K-101-EM1-6 L.O. cooler fan propane compr. A/B/C
230-K-101-PM 1-3 L.O. pump for propane compr. A/B/C
22 KW x8
7.15 KW x6
6.7 HP x3
E. Depropanizer and Condensate Stabilization System 400 V
230-EM-107A/B Depropaniser overhead condenser fan
230-PM-102 Depropaniser reflux pump
7.5 KW x2
1.7 HP
230-H-106 Depropaniser reboiler heater
235-EM-202A/B Condensate cooler fan
106 HP
11 KW x2
230-PM-101 Depropaniser overhead feed pump 7.1 HP
235-KM-201 235-PM-102D/E Vapoor recovery compr. Condensate shipping pump 29.5 HP
40 HP x2
F. Residue Gas Compressor System 400 V
242-EM-301/401 A-D Residue gas compr. After cooler 15 KW x8
G. Air Compressor, and Utility
400 V
251-A-201 N2 generation 30 KW
252-PM-101 C-G 251-KM-201 A/B 252-PM-104 A/B Air compressor A/B Well water lift pump Portable water pump 5.36 HP x5 120 HP x2 7.4 HP x2
252-PM-105 A/B Amine makeup water pump A/B 15 HP x2
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H. Flare, and Water handling 400 V 248-P-101/201 A/B Flare KO drum A
258-PM-202 A/B Produced water injection pump A/B
3 HP x8
60 HP x2
3.3
257-PM-201 A/B/C Heat medium circ. pump A/B/C 49.5 HP x3
FINDINGS AND RECOMENDATION
1. Instrumentation and Metering Based on the site survey founded that many metering and instrument are not work properly. Findings and recommendations of metering and instrumentation at Suban Gas Plant are as follows :
Equipments 1.
2
3
4
Amine Reb HM Heater
H-M Heater
Gas Turbine Generator
Gas Turbine Compressor
Findings
There are inaccurate temperature indicator of circulation Hot Water
Combustion analyzer in each HM Heater not work properly
Recommendations
the oxygen analyzer should be repaired
Need to calibrate meter of hot water temperature indicator
No Oxygen analyzer
The calculated efficiency of HM Heater from direct method difference with heat loss method. This discrepancy maybe caused by lack of accuracy of Temperature indicator and hot water circulation flow meter.
Need to install oxygen analyzer in order to monitor the performance of this equipment
Need to calibrate temperature indicator and hot water circulation flow meter
Need to install fuel gas flow meter and link to DCS
Need to calibrate fuel flow meter and
There is no flow meter of fuel gas in each GTG.
Some indicator/sensor of GTGs have no link to DCS in CCR
lack of meter
accuracy fuel
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link to DCS 5
Propane compressor
No power record for propane compressor
Need to implement continues record for propane compressor to evaluate COP
6
Chiller
Temperature inlet and outlet gas chiller are inaccurate
need to install temperature indicator inlet and outlet gas chiller for performance evaluation and link to DCS
7
Air compressor
No power meter for air compressor
need to install meter of air compressor for performance evaluation and link to DCS
8
Pumps
No power meter for lean amine booster pump
need to install meter of lean amine booster pump for performance evaluation and link to DCS
9
Heat Exchanger
No temperature and pressure indicator at gas-gas exchanger
Temperature indicator of steam at amine Re-boiler are not accurate
Need to install temperature indicator at gas-gas exchanger for performance monitoring Need to calibrate the steam temperature indicators at amine re-boiler
10
Amine system
Temperature indicator between inlet and outlet are not accurate
Recalibration temperature indicator
11
Electric Distribution
No continue recording for electrical distribution
Need to record electrical distribution (6000 V line) at daily records
of
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Page 54 of 109
2. Heater Based on the calculation bellows are the efficiency, heat absorb and CO2 emission of fired heater at Suban Gas Plant
EFFICIENCY
HEAT DUTY
CO2 EMISSION
%
MMBtu/hr
Lb/hr
DESIGN
89.11
57.98
10,609.42
225-H-111
85.80
31.81
5,730.36
225-H-211
84.87
28.70
5,203.54
DESIGN 257 H-101A/B
84.00
4.37
712.53
257-H-101A
73.60
5.35
1,122.86
257-H-101B
OFF
OFF
OFF
DESIGN 257 H-201A/B
84.00
7.94
1,552.85
257-H-201A
81.18
7.38
1,404.86
257-H-201B
80.73
6.66
1,275.47
AMINE REB H-M HEATER
HEAT MEDIUM HEATER
Finding : The above tables shows that :
The heat duty of Amine H-M Heater is only 50 % and 44 % load compare to design condition. The Gas Plant are operated at 517 MMSCFD of sales gas or 74 % load compare to design condition. This condition means that the design of fired heater is too large.
Amine H-M Heater is operated at high excess air (44 % and 71 % ) compare to the design figure which is 15 % excess air. This excess air will impact lower efficiency of H-M Heater
HM Heater is operated at high excess air (62 %, 86 % and 179 % ) compare to the design figure which is 15 % excess air. This excess air will impact lower efficiency of Heater (Calculated Efficiency from heat loss method will be around 70 % compare to design is 84 %)
Recommendation :
Design Amine H-M Heater is too large, so the heater can be handle for revamping until 125 % Amine Capacity.
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Amine H-M Heater is the main energy consuming equipment in the amine system, so its performance should be monitored daily. Hence, it needs temperature and O2 meters at flue gas line to support the monitoring activity.
Amine H-M Heater should be operated close to the design excess air (15%) to achieve better efficiency,
HM Heater should be operated close to the design excess air (15%) to achieve better efficiency
5. Gas turbine generator Based on the calculation, bellows are the efficiency, heat rate, BHP and CO2 emission of GTG at Suban Gas Plant:
GAS TURBINE GENERATOR
EFFICIENCY
HEAT RATE
BHP
CO2 EMISSION
%
BTU/KWH
KW
Lb/hr
DESIGN
30.43
11,336.00
6,063.54
9,803.22
247-GT-201A
18.04
16,924.65
2,235.42
5,610.65
247-GT-201B
18.06
16,908.92
2,189.58
5,610.65
247-GT-201C
18.01
16,949.55
2,268.75
5,610.65
Finding :
Three GTGs load are low in daily operation ( less then 40%),.the average efficiency is around 18 % (design = 30 %)
Heat rate of three GTGs are around 16.9 MBtu/KWH compare to design 11.3 MBtu/KWH
Recommendation :
To achieve better efficiency, GTGs should be operated at more then 50 % load (two GTGs in operation)
Load shading should be operated properly to sustain two GTGs in operation
6. Gas turbine Compressor Power require and energy intensity of residue gas compressor are as follows :
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Page 56 of 109
SALES GAS FLOW, MMSCFD
POWE REQUIRE, KW
ENERGY INTENSITY, KW
DESIGN 242-K-301
235.00
4,537.09
7,936.81
242-K-301
206.00
2,835.13
9,896.28
242-K-401
206.00
2,651.33
9,940.95
DESIGN 242-K-101 242-K-101
300.00 150.00
4,653.97 1,940.43
8,792.49 10,406.28
OFF
OFF
OFF
242-K-102
Turbine efficiency, heat rate and CO2 emission are as follows :
TURBINE
Turbine Eff,
Heat Rate
CO2 emission :
%
Btu/BHP
lb/hr
DESIGN 242-KT-301
29.13
7,878.86
5,341.69
242-KT-301
23.53
9,746.77
1,838.04
242-KT-401
23.35
9,942.20
1,753.20
DESIGN 242-KT-101
25.89
8,793.54
6,070.11
242-KT-101
21.78
10,737.29
1,385.60
242-KT-102
OFF
OFF
OFF
Finding :
Max capacity of KT-401 and KT-301 are 235 MMSCFD each, with suction press 950 psi and discharge 1280 psi
Max capacity of KT-201 and KT-101 are 300 MMSCFD each, with suction press 950 psi and discharge 1200 psi
Actual turbine efficiency of KT-401 and KT-301 is around 23 % and KT-101 is 22 % compare to design efficiency of KT-401 and KT-301 are 29 % and KT-101 is 26 %
Based on the design flow rate, 3 GTCs can handle 770 MMSCF
7. Propane Compressor Performance of propane compressor are as follows :
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POWER REQUIRED, KW
DESIGN
Page 57 of 109
ACTUAL POWER, KW
COP
1,214.78
1,300.00
1.89
230-K 101 A
966.64
1,110.00
1.78
230- K 101 C
815.11
936.00
1.78
Finding :
Inlet flow of refrigerant vapor to propane compressors come from one header, so difficult to evaluate COP each compressor.
Design COP of propane compressor is 1.89, calculated COP at actual condition (based on heat absorb) is around 1.78
8. Gas Chiller Performance of gas chiller are asfollows : GAS CHILLER
UNITS
DESIGN
EVAPORATOR (102,201,302,402)
GAS INTAKE TEMP.AT EVAP.
DEG F
1.00
16.00
GAS OUTPUT TEMP.AT EVAP.
DEG F
(10.00)
5.00
SALES GAS FLOW
MMCFD
300.00
533.00
BBL/D
4,000.00
3,000.00
CONDENSATE FLOW HEAT RELEASE
MMBtu/hr
TOTAL POWER
KW
C.O.P
16.52
11.80
2,600.00
1,930.00
1.86
1.79
Finding :
Inlet flow of refrigerant to gas chiller come from one header, so difficult to evaluate COP for each gas chiller
Heat duty of four gas chiller is 11.8 MMBTU/hr compare to design is 16.52 MMBTU/hr. The motor power of propane compressor is 2046 kW
Design COP of gas chiller is 1.86, calculated COP at actual condition (based on heat release) is around 1.79
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9. Pump Finding : Calculated efficiency of pumps are as follows; PUMPS
Flow, GPM Actual
Efficiency, %
Design
Actual
Design
Amine Charge Pump 225-P-102A
265.00
225-P-102B
265.00
1165.00
39.54
76.67
39.54
Amine Booster Pump 225-P-101A
225.00
225-P-101B
225.00
1430.00
22.04
73.81
22.04
Amine Reboiler H/M Circulation Pump 225-P-111A
2211.00
3044.00
69.83
225-P-111B
2186.00
69.04
225-P-211A
1911.00
66.71
225-P-211B
1911.00
66.71
74.43
Amine charge pumps and Amine booster pumps were running in low efficiency. This is due to very low of fluid rate they handled. Should two split of flow that flowing through “Amine booster pumps is merged together to flow through one pump only(530 GPM), its total flow still far below the rate of design (1165 GPM). The similar case was found at Amine booster pumps. Two pumps were running to handle 225 GPM rate each. Recommendation : Higher efficiency could be achieved should the fluid flowing is handled by one pump only (If total rate of flow not exceed flow rate at design). 10. Cooler Findings : Calculated of coolers are as below: No .
COOLER
HEAT DUTY
HEAT TRANSFER RATE
ELECTRIC/ HEAT DUTY
(MMBTU/HR)
(BTU/HR.FT2.oF)
(%)
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1.
2.
3.
4.
5.
6.
Page 59 of 109
Inlet Gas Cooler 215-E-101
28.37
4.46
0.63%
215-E-201
28.37
4.46
0.63%
215-E-301
43.04
3.08
0.42%
215-E-401
43.04
3.08
0.42%
225-E-105
4.62
3.91
4.19%
225-E-205
3.87
2.95
4.90%
225-E-305
5.35
1.89
3.77%
225-E-405
OFF
OFF
OFF
225-E-101
9.26
1.94
0.65%
225-E-201
13.23
2.68
1.03%
225-E-103
16.78
1.60
0.72%
225-E-203
16.25
1.53
0.74%
235-E-102
1.98
1.11
1.53%
235-E-202
3.75
2.12
0.86%
Propane Cooler 230-E-104
19.15
2.59
0.31%
Treated Gas Cooler
Regenerator Reflux Condenser
Lean Amine Cooler
Condensate Cooler
Power required to drive motors of fan coolers are below 1% due to their heat duties. This condition indicate that the power consumption of these coolers are in good condition except Treated gas cooler and Condensate cooler. Recommendations : Need to check again the performance of Treated gas cooler and Condensate cooler, especially motor driver of fan coolers. 11. Heat Exchanger Findings : Calculated of Heat Exchangers are as listed below: No.
1.
HEAT EXCHANGER
Stabilizer Reboiler
HEAT DUTY
HEAT TRANSFER RATE
(MMBTU/HR)
(BTU/HR.FT2.oF)
DIRTY FACTOR ACTUAL
DESIGN
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2. 3.
4.
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235-E-101
2.21
39.14
0.0009
0.0010
235-E-201
3.02
48.13
0.0034
0.0010
De-C3 Reboiler 230-E106 Rich/Lean Amine Exch.
0.18
N/A
N/A
N/A
225-E-104A/B
16.40
N/A
N/A
N/A
225-E-204A/B
20.96
N/A
N/A
N/A
Gas-Gas Exch. 230-E307
14.00
157.31
0.0023
0.0020
The performance of heat exchangers still in good condition, except for Stabilizer Reboiler 235-E-201, because the dirty factor more than design specification. 12. Energy Losses, Potential Saving and Emission Reduction Potential Based on heat balance calculation, energy losses from high temperature flue gas at Suban is coming from Stack of Thermal Oxidizer, GTG and GTC.
STACK LOSS, Btu/hr
TEMP, Deg F
Thermal Oxidizer 225-H-102
35,495,414
932
225-H-202
8,303,983
2,012
247-GT-201A
33,163,974
916
247-GT-201B
29,310,275
921
247-GT-201C
29,397,944
925
242-K-101
21,555,786
1,213
242-K-301
22,755,271
1,261
242-K-401
21,806,787
1,237
201,789,433
1,177
GTG
GTC
TOTAL
a. Energy Losses : Total losses from flue gas is around 201 MMBtu/hr with average temperature 1,177 deg F. Actually, by utilizing economizer with stack temperature around 500 deg F, this Flue gas losses can be used to generate saturated steam about 120,000 lb/hr.
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b. Potential Saving : Based on the evaluation, shows that the potential saving are coming from :
Optimize operation of GTG will increase efficiency from 18 % to 23 % that will reduced HP Fuel consumption about 0.14 MMSCFD
Optimize operation of all heater will increase efficiency around 5 %, that will reduced LP fuel consumption about 0.1 MMSCFD
Utilized flare gas that will reduced fuel consumption about 0.8 MMSCFD
Energy Conservation Opportunities :
Optimize operation of GTGs can be implemented by load shading
Optimize operation of Heater and utilized flare gas can be implemented by installing booster compressor to compress gas up to 180 psig. This fuel gas can be used for Gas turbine and in turn it will reduce HP Fuel consumption. The simple calculation are as follows :
Fired Heater-saving, MMSCFD
0.10
, US $/Year
123,750.00
Flare Gas-saving, MMSCFD
0.80
, US $/Year
990,000.00 Total, MMSCFD
0.90
, US $/Year
1,113,750.00
*Cost to install the system for recovery gas which includes : gas compressor, KO Drum, Instrumentations , US $
2,400,000.00
Operation and Maintenance Cost , US $/year
120,000.00
Net income , US $/Year
993,750.00
Estimated payback period to install the system , Years
2.42
* = refer to Beak Pacifik Report - Energy Audit at Cilacap Refinery Complex (Beak Pacific Inc. , Vancouver, Canada)
c. Emission Reduction Potentials CO2 emission at suban gas plant is 127,901 lb/hr. its come from combustion of fuel gas at flare gas, heater, GTC and GTG.
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CO2 reduction, lb/hr Optimized operation of GTG
642
Optimized operation of Heater
824
utilized flare gas
7,394 Total
8860
Optimised operation and utilized flare gas will reduce CO2 emission , %
7%
13. Reporting system Findings :
Existing daily report just only for production activity, it does not cover the data for plant performance evaluation purposes
No data acquisition and evaluation based on daily log sheet .
Important data for plant performance not covered in daily log sheet
Recommendation :
Daily reporting must covers production activity and plant performance indicator
Regulars summary of log sheet regarding plant performance should be evaluate.
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IV. ENERGY ASSESSMENT CENTRAL GAS PLANT
AT
GRISSIK
4.1. GENERAL PLANT OPERATION AND PERFORMANCE 4.1.1. GENERAL PLANT OPERATION OF GRISSIK GAS PLANT The Central Gas Processing – Grissik plant was designed firstly for processing gas from four field in the Corridor Block, South Sumatra: Dayung/Sumpal and GLT (Gelam/Letang/Tengah) field. The quality gas from Dayung field has high CO2 content (31 %) and the gas quality from GLT has high condensate content. The source of inlet gas to be processed in CGP has changed after the Suban Gas Plant was operated. Partly of Suban Gas sales line also was processed in CGP if the specification of Suban Gas Sales was nearly out of specification, especially on the CO2 content. So, the mixed gas from Suban plant and CGP plant will meet specification at the gas sales pipeline. The simple process flow of CGP-Grissik Plant is shown with block diagram in figure 1.1 below: FlareGas T
11
T
1
T
2A
Gas/Liquid Separation
Dayung Gas Gathering Station
2B
T Gas Pretreatment
Permeate Gas
Acid Gas
5
6
Suban Gas Sales bypass
7
T
4
T Amine System
GasDehydrationSystem T
T
GelamGas
T
GasSales to pipeline
Propane Chiller
8
Gelam Liquid Gelam Gas/Liq GatheringStation
9
Suban Gas Sales toprocessedin CGP 3
T
10
Condensate Stabilization Condensateproduct to Bentayan & C3 Recovery
Figure 4.1 Gas Processed Block Diagram of CGP plant The flow diagram of CGP Grissik plant that obtained from basic design and field survey can be described below:
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Table 4.1. Flow Diagram (based on Design) Unit Temp (deg F) Pressure (psig) Flow, Gas (MMSCFD) Flow, Cond. (BBL/D) TOT_FLOW(MMSCFD)
1
3
2B
Stream 5 6
4
7
8
9
10
11
GlmLiq. to Dy&Sum Glm Dyg/Smp Codensat Dy&Sum Dy&Sum Dy&Sum Dy&Sum Dyg/Sum GlmGas AcidGas FlareGas GlmGas GlmGas GlmGas GlmGas Stabilizer Gas Condensate Gas e prod. Gas Gas Gas#1 Gas #2 Gas
87
87
53
1000 1000 176 310 129.46 0 0 0 520.2 439.46
ORBBL/D
2A
520.2
100
58
1121 1133 1099 1133 1099 9 302.2 129.46 114.02 129.46 114.02 70.22 0 0 0 0 0 0
120
11 1093 1125 1094 1087 1119 575 46.5 197.56 114.38 0 197.06 114.1 0 0 0 0 1745 0 777.83 0
75 0.16 0
302.2 129.46
46.5
1745
0.16
10
11
84
99
84
99
357.5
99
120
120
70.22
120
50
311.94
777.83
132
130
311.16
Table 4.2. Flow Diagram (Survey on Oct. 02, 2007)
Unit Temp (deg F) Pressure (psig) Flow, Gas (MMSCFD) Flow, Cond. (BBL/D) TOT_FLOW(MMSCFD) OR BBL/Dfor Liquid
1
3
2A
2B
Stream 5 6
4
7
GlmLiq. to Dy&Sum Dy&Sum Dy&Sum Dy&Sum DSS*) Glm Gas AcidGas GlmGas Glm Gas Sub Gas Stablzr Gas Gas Gas Gas Gas
87
87
84
138
1105 1011 142 1001 0 53.2 47.1 53.2 0 0 866.77 0 100.3035
866.77 100.3
84
123
84
87
109 143.15 120
8
GlmGas
Glm Cond.
120
37
9
Bypass DSSGas GlmGas Cod. prod. FlareGas Sub
94.5
93.1
90
80
1001 1023 47.1 46.7 0 0
1001 1000 47.1 101.6 0 0
23 2.57 0
993 203 12.1 993 1000 1000 998 20.6 132.85 41.95 0 434.68 146.46 39.39 0 0 0 829.95 0 0 0 1296 0
205 5.75 0
47.1
195.4
2.57
20.6
5.75
174.8
829.95
620.53
1324
*) DSS : Dayung/Sumpal & Suban
Based on overall process, the processing load of CGP plant during field survey activity is 54.6% of capacity design. This condition is caused by shut down condition for repairing of the Amine Regenerator 25-C-202. 4.1.2. GENERAL PLANT PERFORMANCE OF GRISSIK CENTRAL GAS PLANT The HP fuel gas supply for the plant is obtained from the Back-up sales gas line and Suban taping gas line via the pressure control valve. Gas heated by steam, under back pressure control, goes to the high pressure fuel gas scrubber which is operated at about 260 psig. The high pressure fuel gas supplies fuel the gas turbine and partly sent to Bentayan field. The LP fuel gas from the stabilizer feed drum and stabilizer overhead is supplied for TEG regeneration heater, gas pretreatment heater, fuel gas for WHB incenerator and flare purge gas, flare stack pilot, tank blanket. The HP fuel gas is supplied to GTG and to the LP fuel gas, when the LP gas demand exceeds the available LP fuel gas supply. CGP Grissik plant used three (3) type of energy for the process, utility and offsites facilities. The types of energy that used are : LP Fuel gas, steam from WHB and electricity from GTG. Based on 2 October 2007, the amount of fuel gas coming from scrubber is 5.910 MMSCFD. The distribution of fuel gas as shown in table below;
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Table 4.3 : Fuel gas distribution
1 Fuel Gas to Flare C
1.460
46-B-101
D
1.550
46-B-201
D
-
D
1.550
41-H-101
C
0.023
41-H-201
C
0.023
41-H-301
C
-
C
0.045
21-H-101
C
0.161
21-H-201
C
-
2 Fuel Gas to WHB
3 Fuel gas to Heater
4 Fuel gas to Regen Heater
0.161 5 Fuel gas to GTG 47-GTG-101A
C
0.70
47-GTG-101B
C
0.78
47-GTG-101C
C
-
D
1.48
D
1.560
6 Fuel gas to Bentayan
There are two type of fuel gas used, LP Fuel gas which is consumed by fired heater and HP Fuel gas which is consumed by GTG. The heating value of LP Fuel gas is around 1,060 Btu/SCF and HP Fuel is around 1,484 Btu/SCF Based on heat balance calculation in WHB and GTG, the energy picture based on 2 October 2007 which includes total energy input/heat released, heat absorbed, heat loss and CO2 emission as shown in table below,
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Table 4-4 : The energy picture based on 2 October 2007 HEAT RELEASE, Btu/hr
HEAT ABSORB, Btu/hr
STACK LOSS, Btu/hr
TEMP, Deg F
CO2 Emission, lb/hr
FLARE 90,840,020
0
84,736,763
1,562
12,421
21-H-101
8,473,864
5,794,116
2,487,229
430
1,377
21-H-201
0
0
0
0
0
41-H-101
1,196,695
922,279
256,466
430
191
41-H-201
1,196,695
922,279
256,466
430
191
41-H-301
0
0
0
0
0
46-B-101
165,049,729
120,492,608
41,432,959
376
158,802
46-B-201
0
0
0
0
0
47-GTG-101A
37,103,706
7,084,939
19,478,242
949
4,569
47-GTG-101B
40,880,730
7,415,749
18,133,682
967
5,034
47-GTG-101C
0
0
0
0
0
344,741,441
142,631,970
166,781,807
468
182,585
HEATER Regen Gas Heater
Glycol Heater
WHB
GTG
TOTAL
Plant Performance : The plant performance at 2 October 2007 are as follows : Table 4-5 : Plant Performance of Grissik Central Gas Plant PRODUCTION RATE Sales Gas = =
186.50 MMSCFD 31,083.33 BOE
Condensate =
1,234.00 BOE
Total Prod =>
32,317.33 BOE
ENERGY CONSUME Excluding Flare Including Flare
256,621,725.71 Btu/hr 347,461,746.16 Btu/hr
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ENERGY INTENSITY Excluding Flare Including Flare
Page 67 of 109
7,940.68 Btu/BOE 10,751.56 Btu/BOE
Total heat input to WHB, GTG,Regeneration Gas Heater and Glycol Heater is 253,901,420 Btu/hr and total heat released including flare gas is 344,741,441 Btu/hr. The production rate is 32,317.33 BOE which include 186.5 MMSCFD sales gas and 1,234 Barrel of condensate, means the energy consumed to produce one BOE (energy intensity) is 7,940.68 BTU/BOE (Excluding flare) and 10,751.56 BTU/BOE Including flare).
4.2. PERFORMANCE EVALUATION EACH SYSTEM 4.2.1. GAS PRETREATMENT & MEMBRANE SYSTEM A. DESCRIPTION The Gas Pre-Treatment Unit has been designed to operate at 2 x 50% each train with a total gas throughput capacity of 230 MMSCFD and designed to remove heavy hydrocarbons (C6+) from 380 ppm to 39 ppm. The overall process works on the principles of Adsorption, Regeneration and, Cooling and, is commonly referred to a Thermal Swing Adsorption (TSA) process. Each train has 4 Adsorber Towers. Under normal operation each train has 2 Adsorber towers in operation mode,one Adsorber Towers in Regeneration mode and one Adsorber Towers in cooling mode. The pretreatment consists of the following four steps process, i.e :
Coalescing filter for the removal of aerosols and particulates;
Heater to ensure the gas is above the dewpoint temperature;
Guard bed for the removal of heavy hydrocarbons and glycol;
Polishing filter
The Dayung gas from inlet separator is sent to the membrane unit to remove CO2, lowering the CO2 content of the gas from about 30.5 mole% to less than 15.0%. The Membrane CO2 separation unit was designed to process the Dayung gas to reduce the CO2 content of the gas from 31% to 15%. The remainder of the CO2 in the Dayung gas is then removed in the Amine-treating Unit, allowing the gas to meet the sales gas pipeline specification for CO2, which has a minimum value of 5%. As the Dayung gas flows through the semipermeable polimide membranes, approximately 63% of the CO2, 60% of the H2S, and 8% of the Methane is separated into the permeate gas stream. The permeate Gas, consisting of about 80% CO2 and 20% Methane, is sent to the Waste Heat Boilers as fuel gas.
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B. PERFORMANCE The main equipment at Gas Pretreatment (TSA) system are Regenerator Gas Heater and Regen Gas/Gas Exchanger The performance of main equipment are as follows : Table 4-6 : Performance of Performance of Regenerator Gas Heater : 2-Oct-07 21-H-101
DESIGN
21-H-201
21-H-101/201
1 FUEL, Flow, MMSCFD
0.16
OFF
0.31
T out, F
430.00 (Estimated)
OFF
430.40
O2, %
14.00 (Estimated)
OFF
14.00
Excess Air, %
185.64
OFF
185.64
Heat absorption (LHV), MMBtu/hr
5.75
OFF
11.06
Heat absorption (HHV), MMBtu/hr
5.80
OFF
11.16
Efficiency (LHV), %
74.65
OFF
74.62
Efficiency (HHV), %
68.40
OFF
68.38
1,376.93
OFF
2,651.23
2 FLUE GAS
3 PERFORMANCE
4 CO2 EMISSION CO2 Emission from fuel gas, lb/hr
Regen gas heater is operated at 60% load compare to design condition and the fuel consump is 0.16 MMSCFD The stack temperature and oxygen content are estimated close to design condition with the efficiency is 74.65 %
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Table 4-7 : Performance of Regen Gas/Gas Exchanger (21-E-101/201)
21-E-101
21-E-201
DESIGN
Gas to Membrane (Shell side) Pressure, psig
1097
OFF
1153
Temp inlet, F
85.00
OFF
85.78
Temp outlet, F
100.00
OFF
110.40
Flowrate of Gas, MMSCFD
26.00
OFF
215.07
Temp inlet, F
230.00
OFF
309.90
Temp outlet, F
109.00
OFF
95.00
Delta T LMTD
62.74
OFF
61.89
HEAT DUTY, Btu/hr
475,664
OFF
7,497,708
HEAT TRANSFER RATE, BTU/(Hr/Ft2.F)
3.12
OFF
6.26
Hot Gas (Regen Gas)
Table 4-8 : Performance of Cooler Gas/Gas Exchanger (21-E-102/202) 21-E-102
21-E-202
DESIGN
Regen Heater Gas/Hot Gas (Shell side) Pressure, psig
1097
OFF
1155
Temp inlet, F
400.00
OFF
541.60
Temp outlet, F
230.00
OFF
309.90
Flowrate of Gas, MMSCFD
20.00
OFF
25.93
Temp inlet, F
102.00
OFF
85.90
Temp outlet, F
120.00
OFF
335.60
Delta T, LMTD
194.18
OFF
212.40
HEAT DUTY, Btu/hr
4,674,675
OFF
8,267,466.11
Cold Gas (Regen Gas)
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HEAT TRANSFER RATE, BTU/(Hr/Ft2.F)
44.17
Page 70 of 109
OFF
55.43
The above table shows that the heat duty operated only about 0.475 MMBTU/hr for E101 and 4.67 MMBTU/hr for E-102, although the design heat duty is 7.5 MMBTU/hr for E-101 and 8.26 MMBTU/hr for E-102. This heat duty value produce capacity only about 6.34 % for E-101 and 56.54 % for E-102 compare to design capacity. This condition caused by the feed gas to TSA unit only 26 MMSCFD (110,283 lb/hr) for adsorption and 20 MMCSFD (87,483 lb/hr) for cooling condition compare to the design capacity for gas process adsorption is 115 MMSCFD (20% capacity). The different between design and operation are the LMTD value. Actual LMTD is 62.74 oF for E-101 and 44.17 oF for E-102 compare to design is 61.9 F for E-101 and 55.43 oF for E-102. The performance of heat exchanger can be evaluated from the value of overall heat transfer rate (U). The U at operating condition give value about 3.12 BTU/(Hr/Ft2.F) for 21-E-101 and 44.17 BTU/(Hr/Ft2.F for 21-E-102, while the design value is 6.26 BTU/(Hr/Ft2.F) for 21-E-101 and 55.43 BTU/(Hr/Ft2.F) for 21-E-102. 4.2.2. AMINE SYSTEM A. DESCRIPTION The gas treating process consists of three identical amine contactors, two normally treating about 114 MMSCFD of Dayung gas each (referred design base) and the third treating about 129 MMSCFD of Gelam, Letang, Tengah (GLT) gas. The amine units are designed to produce treated gas containing less than 2% CO2 and 4 ppmV H2S consequently the bypasses allow the sales gas still to meet its specification of 5% CO2 and 8 ppmV of H2S. Amine unit feed gas stream enters the bottom of an amine contactor where it is counter-currently contacted with lean 50 wt% UCARSOL solution with main composition is MDEA solution. CO2 and H2S are absorbed by the lean amine and the treated gas exits the top of the tower. The amine contactor contains stainless steel structured packing. The design lean amine circulation rate to the Dayung gas contactors is about 1640 US gpm and the design lean amine circulation rate to GLT gas is about 1621 USgpm based on maximum allowable rich amine loading of 0.49 mole (CO2+H2S)/mole UCARSOL (MDEA solution). The rich amine from the contactors flows under level control to the rich amine flash drums. Gas from the flash drums flows under back pressure control to the waste gas incenerators. The rich amine flows under level/flow control through the lean/rich amine exchangers where it is heated to about 206 oF by heat exchange with the hot lean amine from the two regenerators.
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The rich amine feeds the regenerator above the stripping section which contains stainless steel structured packing. CO2 and H2S are stripped from the rich solution by steam produced in the regenerator reboilers which consist of 4 (four) kettle type shell and tube heat exchanger for each regenerator. B. PERFORMANCE The main equipment of amine system are Regenerator Reflux Condenser 25-E101/202, Amine Reg. Reboiler 25-E-102A-D /202A-D , Lean amine cooler 25-E103/203, Rich / Lean Amine Exchanger 25-E-104A/B, 25-E-204A/B; Amine Charge Pump 25-P-102A/B/C; Amine Booster Pump 25-P-101B/C Table 4-9 : Performance of Amine Regenerator Re-boiler:
25-E-102A-D
25-E-202A-D
DESIGN
Pressure, psig
63.00
OFF
50.00
Temp sat'd steam, F
300.00
OFF
297.00
Flowrate Steam (25-FIC-121), Lb/hr
101,954.00
OFF
101,564.00
Flowrate Steam (25-FIC-122), Lb/hr
102,586.00
OFF
101,564.00
259.50
OFF
261.00
1,309,729
OFF
1,299,665
44.25
OFF
39.25
184,589,323
OFF
194,088,804
132
OFF
173
STEAM SIDE (SHELL):
AMINE SIDE (TUBE): Temp amine to Regenerator, F Flow of Rich Amine to be regenerated, Lb/hr Delta T HEAT DUTY, Btu/hr HEAT TRANSFER RATE, BTU/(HR.Ft2.degF)
The above table shows that the actual heat duty is closed to the design. The difference between actual heat duty and design value only 5%, although the flow rate regenerated rich amine higher than design, the temperature outlet of amine reboiler less than design (actual is 249.5 deg F and design value is 262 deg F). The overall heat transfer rate (U) at actual condition is 132 BTU/(Hr/Ft2.F) compare the design is 173 BTU/(Hr/Ft2.F. This condition caused by the LMTD of actual is higher than design value.
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Table 4-10 : Performance of Lean Amine Cooler : 25-E-103
25-E-203
DESIGN
Pressure, psig
110.00
110.00
180.00
Temp inlet, F
190
190
224
Temp outlet, F
106
104
120
799,305
670,882
1,375,016
Temp inlet, F
92
92
95
Temp outlet, F
129
129
141.3
Delta T LMTD
31.93
30.14
48.20
62,223,295
53,469,455
123,624,938
336.84
367.46
447.60
ACTUAL FAN OPERATED
11
12
12
CALCULATE FAN OPERATED
6
5
12
HEAT TRANSFER RATE, BTU/(HR.Ft2.degF)
2
2
3
LEAN AMINE side:
Flowrate of Lean Amine, Lb/hr AIR COOLANT side:
HEAT DUTY, Btu/hr ELECTRIC CONSUMPTION, KW
The above table shows that the heat duty actual of 25-E-103 and 25-E-203 are operated at 50% to the design. This caused by the flow rate of lean amine to be cooled also only about 50% - 60% from design capacity. The flow rate of lean amine does not affect to the power required of fan cooler driver, so the power required to motors also higher than calculated value. At this case, the actual fan be operated closed to design (11 fans for 25-E-103 and 12 fans running for 25-E-203). This condition related with performance of cooler, especially with heat transfer rate. The U (overall heat transfer rate) at operating condition give value about 2 BTU/(Hr/Ft2.F) for operated and 3 BTU/(Hr/Ft2.F for the design value. This difference indicated that the performance of cooler lower than the design performance. Table 4-11 : Performance of Rich-Lean Amine Exchanger: 25-E-104A/B
25-E-204A/B
108.00 155.00 203.00
OFF OFF OFF
DESIGN
RICH AMINE SIDE Pressure, psig Temp inlet, F Temp outlet, F
95.00 167.00 206.00
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Flowrate of Rich Amine, USGPM LEAN AMINE SIDE Temp inlet, F Temp outlet, F Delta T LMTD HEAT DUTY, Btu/hr HEAT TRANSFER RATE, BTU/(Hr/Ft2.F)
Page 73 of 109
2,572.00
OFF
2,496.80
250.00 229.00 59.48
OFF OFF OFF
261.00 224.00 55.99
53,656,356 N/A
OFF OFF
42,413,111 N/A
The above table shows that the heat duty operated of exchanger 25-E-104A/B is higher than design value. The difference is about 25% higher than design. The different heat load should be caused by :
Design amine is CR302, but the actual operation is AP-16668. The difference of amine causes different specific heat.
Flow rate of rich amine at operation is higher than the design value (3.5% difference)
The difference between operated LMTD and design is 6.5%.
Table 4-12 : Performance of Regenerator Reflux Condenser : 25-E-101
25-E-201
DESIGN
218.47 143.15 20.60
OFF OFF OFF
217.00 120.00 23.25
92.00 132.00 67.27
OFF OFF OFF
95.00 131.60 57.60
55,701,905
OFF
61,714,112
23.79 11.00 10.83 3.57
OFF OFF OFF OFF
29.84 12.00 12.00 4.19
ACID GAS SIDE : Temp inlet, F Temp outlet, F Flow of acid gas removed, MMSCFD AIR COOLANT SIDE : Temp inlet, F Temp outlet, F Delta T LMTD
HEAT DUTY, Btu/hr ELECTRIC CONSUMPTION, KW ACTUAL FAN OPERATED CALCULATE FAN OPERATED HEAT TRANSFER RATE, BTU/(HR.Ft2.degF)
The above table shows that regen reflux condenser and amine regenerator re-boiler are operated close to design condition. It has difference of heat duty about 11% than the design value. This caused by the flow rate of acid gas to be removed also only
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13% less than the design capacity (operated is 20.6 MMSCFD, and the design value is 23.25 MMSCFD). Power required of motor fan driver also proportional with the exchanger heat duty. At this condition the actual operate 11 fans, and the calculated result is also same fans to be operated. Caused by the flow rate capacity of cooler load, the overall heat transfer also follow with this condition. The U (overall heat transfer rate) at operating condition give value about 3.57 BTU/(Hr/Ft2.F) and 4.19 BTU/(Hr/Ft2.F for the design value. Table 4-13 : Performance of Amine Charge Pump DESCRIPTION
UNIT
25-P-102C
Design
value
value
specific gravity
1.03
1.00
245.00
70.00
Temperature
F
suction pressure
psia
98.00
25.00
discharge pressure
psia
1210.00
1185.00
flow
GPM
2862.00
2487.00
Total head
ft
2,503.97
2679.60
Electric motor power
HP
2240.00
2059.00
Mechanical work
HP
1946.39
1719.89
Efficiency
%
86.89
83.53
Only one Amine charge pump (Charge pump C) was running very close to design condition. It’s efficiency reached 86.89% with flow rate of 2862 GPM, This pump is designed to running with 83.53% efficiency at 2487 GPM flow rate. The pump was running actually in even higher efficiency than the design condition. Attention should be addressed to this situation since the pump draw consumed electric power of 2240 HP. It just below it's maximum power rating: 2250 HP. Table 4-14 : Performance of Amine Booster Pump DESCRIPTION
UNIT
specific gravity
25-P-101B
25-P-101C
Design
value
value
value
1.03
1.03
1.00
180.00
180.00
70.00
Temperature
F
suction pressure
psia
16.70
18.70
N/A
discharge pressure
psia
119.70
129.70
N/A
flow
GPM
1556.00
1306.00
2871.00
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Total head
ft
231.93
249.95
188.00
Electric motor power
HP
142.00
136.00
170.00
Mechanical work
HP
98.02
88.66
139.30
Efficiency
%
69.03
65.19
81.94
Two of the Amine booster pumps were running. They were Amine Booster pump B and C. Their efficiencies are 69.03% at 1556 GPM and 65.19% at 1306 GPM respectively. At the other side, we have data from design condition when each pump handles 2871 GPM. At this design condition, we got 81.94% efficiency. These two pumps were running in good condition and within the range of operation. 4.2.3. REFRIGERATION SYSTEM A. DESCRIPTION Propane refrigerant gas from gas chiller at 75 psig, compress by propane compressor (single stage screw compressor). The compressor discharge at about 252 psig goes to the propane condenser where it is totally condensed at about 122 oF. The propane condenser is an air cooled heat exchanger. The condensed propane goes to the propane accumulator and then to the gas chiller via the level control valve. The refrigerant chills the sales gas from 57 F to 45 F and then goes to LTS to separate the gas from the condensate. B. PERFORMANCE The main equipment at Refrigeration System are Exchanger (Gas chiller 30-E-102), Propane compressor 30-K-101A/B and Gas/Gas Exchanger. Table 4-15 : Performance of Gas Chiller UNITS
DESIGN
EVAPORATOR
TEMPERATURE GAS IN
DEG.F
57.00
57.00
TEMPERATUR GAS OUT
DEG.F
45.00
45.00
GAS FLOW
MMCFD
100.00
39.00
CONDENSATE FLOW
BCD
700.00
700.00
HEAT RELEASE
BTU/H
ACTUAL POWER
KW
C.O.P
2,477,633.80
841,348.85
260.00
110.00
2.79
2.24
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The above table shows that the refrigeration system operated at low load and the propane chiller are operated at 40 % load (39 MMSCFD ) at actual power 110 KW compare to design condition. The COP at actual condition is 2.24 compare to design value is 2.79 Table 4-16 : Performance of propane compressor Only one compressor is operated to handle the refrigeration system. The operating conditions are as follows;
UNITS SUCTION TEMPERATUR
DESIGN
ACTUAL
o
35.00
30.00
o
127.00
120.00
14,000.00
7,191.72
( F)
CONDENSING TEMPERATUR
( F)
PROPANE FLOW
LBS/H
TOTAL POWER REQUIRED
KW
242.17
101.64
ACTUAL POWER
KW
260.00
110.00
3.00
2.87
COP
(Calculated)
At the actual condition, the refrigerant flow is 7191 lb/hr at actual power 110 KW and COP = 2.87. Compare to design condition, the refrigerant flow is 14,000 lb/hr at power design 260 KW and COP = 3. It means that the performance of compressor is still in good condition. Table 4-17 : Performance of Gas/Gas Exchanger 30-E-101
DESIGN
Pressure, psig
1000
1120
Temp inlet, F
130.00
129.60
Temp outlet, F
60.00
64.40
Flow rate of Gas, MMSCFD
39.39
114.00
Temp inlet, F
40.00
50.00
Temp outlet, F
120.00
117.00
HOT GAS (FR GELAM CONTACTOR):
GELAM SALES GAS side:
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Delta T LMTD HEAT DUTY, Btu/hr
Page 77 of 109
14.43
13.48
3,159,954
10,705,230.41
0.23
0.30
2
HEAT TRANSFER RATE, BTU/(Hr/Ft .F)
The above table shows that gas/gas exchanger at the dew point control system have heat duty only 30% refer to the design value. This caused by the flow rate of gas also only 35%. The temperature profile of gas also not have high different between operated and design value. Caused by the flow rate capacity of gas to the gas/gas exchanger, the overall heat transfer also follow with this condition. The U (overall heat transfer rate) at operating condition give value about 0.23 BTU/(Hr/Ft2.F) and 0.30 BTU/(Hr/Ft2.F for the design value. 4.2.4. CONDENSATE STABILIZING SYSTEM A. DESCRIPTION The hydrocarbon liquid from the feed drum is fed under level control to the top tray of the condensate stabilizer. The stabilizer is a 32 inch ID reboiled stripping column containing 18 stainless steel valve trays. The stabiliser reboiler is a kettle type shell and tube exchanger utilizing about 3404 lb/h of 140# steam at normal operation. During normal operation about 1738 bbl/day of 10 psi RVP condensate are produced. The condensate product from the stabilizer is sent via the HC condensate cooler bundle in the refrigerant condenser air cooled exchanger frame. B. PERFORMANCE The main equipment at Condensate Stabilizing system are Stabilizer Re-boiler 35-E102, and Condensate cooler 35-E-101 Table 4-18 : Performance of Stabilizer Reboiler 35-E-102 : 35-E-102
DESIGN
Pressure, psig
117.00
150.00
Temp sat'd steam, F
330.00
330.00
Flow rate (35-FIC-006), Lb/hr
803.00
3,751.35
Temp Condensate to re-boiler, F
278.00
261
Delta T
66.00
69.40
STEAM SIDE (SHELL)
CONDENSATE SIDE (TUBE)
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HEAT DUTY, Btu/hr
Page 78 of 109
700,201
3,470,000
6.52
30.73
HEAT TRANSFER RATE, (BTU/Hr.Ft2.F)
The above table shows that actual heat duty of 35-E-102 is only 20 % compare to design condition because the flow rate of feed liquid to the stabilizer is only 20 % - 25 % compare to design. Due to the flow rate of stabilizer re-boiler is only 20% than the design, the U (overall heat transfer rate) at operating condition give value about 6.52 BTU/(Hr/Ft2.F) compare with the design value, 30.73 BTU/(Hr/Ft2.F Table 4-19 : Performance of Propane Condenser and Condensate Cooler 30-E-105 FLUID SERVICES:
DESIGN
PROPANE COONDENSOR
35-E-101
DESIGN
CONDENSATE
Pressure, psig
150
250
Temp inlet, F
140.00
158.00
316
316.00
Temp outlet, F
119.00
124.00
120
120.00
4.50
5.13 1324
2,174
Flow rate, MMSCFD (gas) Flow rate, BBL/day (liquid) AIR COOLANT SIDE : Temp inlet, F
92.00
95.00
92
95.00
Temp outlet, F
105.00
109.90
105
109.90
Delta T LMTD
30.83
35.30
53.68
85.85
3,086,550
3,796,245
718,616
1,995,227
14.72
22.38
14.72
22.38
HEAT DUTY, Btu/hr ELECTRIC CONSUMPTION, KW
The arrangement of cooler in this area is designed to serve three stream cooling fluid, i.e : Propane condenser, Propane overhead condenser and condensate stabilizer. Only one fans cooler installed to cool them. At the plant survey, the propane overhead condenser was off. Heat Load total at actual condition of two condenser (30-E-105 and 35-E-101) are 3.8 MMBTU/hr compare with the design value is 5.7 MMBTU/hr. This heat load gives
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percentage about 65 % of heat load capacity similar with electrical consumption is 65 % too. 4.2.5. DEHYDRATION SYSTEM A. DESCRIPTION The water saturated gas from the three amine trains is dehydrated by contacting it with lean triethylene glycol (TEG) in the three, identical glycol contactors. The design water content of the dry gas is 10 lb H2O per MMSCFD. The dehydrated GLT gas is recombined with the GLT amine unit bypass gas, sent through the dewpoint unit and then to sales. The Dayung/Suban gases from two of the glycol contactors and the Dayung/Suban amine unit bypass gas are sent directly to Sales. Lean glycol is fed to the top of the glycol contactor at a rate of about 30-USgpm. A coil is provided in the top of the tower to cool the glycol from about 210 oF to less than 150 oF by heat exchange with the dried gas leaving the contactor. The glycol flows downwards through the structured packing in the column counter-currently contacting and absorbing water from the gas flowing upwards through the packing. The rich glycol accumulates on the chimney tray and is sent under level control to the glycol regeneration skid. The dry gas exits the top of the contactor with the Dayung/Suban gasses going to sales and the GLT gas going to the hydrocarbon dewpoint control unit. The three glycol regeneration skids are identical. There are no connections between the glycol regeneration skids or between the glycol lines in each train. B. PERFORMANCE Table 4-20 : Performance of Rich – Lean Glycol Exchanger 41-E-101
41-E-201
41-E-301
DESIGN
Pressure, psig
10.50
11.50
11.00
50.00
Temp inlet, F
380.00
370.00
360.00
360.00
Temp outlet, F
150.00
165.00
160.00
225.00
Flow rate of Lean TEG, USGPM
20.18
24.00
24.00
30.48
Temp inlet, F
140.00
142.00
140.00
171.00
Temp outlet, F
200.00
200.00
196.00
306.20
Delta T LMTD
58.82
61.13
66.25
51.90
1,400,267
1,477,137
1,439,554
1,485,141
LEAN TEG SIDE
RICH TEG SIDE
HEAT DUTY, Btu/hr
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HEAT TRANSFER RATE, BTU/(Hr/Ft2.F)
104.88
Page 80 of 109
88.55
92.66
128.20
The above table shows that Rich/Lean Glycol Exchanger are operated close to design condition. Its heat duty is only 5% differ than the design value, although the flow rate of glycol at the operation only 70% - 80% than design capacity. This condition is caused by the difference of LMTD between operated and design value. The operating condition gives temperature outlet of Lean glycol lower than design value. Due to the flow rate capacity of cooler load, the U (overall heat transfer rate) at operating condition give value about 70%-80% than the design value. Table 4-21 : Performance of Glycol Heater 2-Oct-07 41-H-101
41-H-201
1 FUEL, Flow, MMSCFD
0.02
0.02
T out, F
430.00
430.00
O2, %
7.00
7.00
Excess Air, %
45.77
45.77
Heat absorption (LHV), MMBtu/hr
0.91
0.91
Heat absorption (HHV), MMBtu/hr
0.92
0.92
Efficiency (LHV), %
84.91
84.91
Efficiency (HHV), %
77.08
77.08
CO2 Emission from fuel gas, lb/hr
191.42
191.42
2 FLUE GAS
3 PERFORMANCE
4 CO2 EMISSION
The heat duty of Glycol heater is 0.91 mmbtu/hr (calculated from process site). Assuming the oxygen content of flue gas is 7%, the calculated efficiency is 84.91%.
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4.2.6. WASTE HEAT BOILER A. DESCRIPTION Permeate gas from membranes, rich amine flash drum gas, and acid gas from the amine reflux accumulators are combined and sent to the waste gas incenerator. In the incenerator, the waste gas is incenerated by burning fuel gas at a sufficient high temperature to ensure the complete destruction (oxidation) of the H2S and hydrocarbons. The minimum exit gas temperature at the top of the stack is 450 oF to ensure that the allowable ground level SO2 concentration is not exceeded. 150 psig saturated steam is produced by two heat recovey boilers with each capacity of 230,000 lb/h. Normally, two boilers are operated to supply necessary steam for all users in CGP. B. PERFORMANCE The main equipment of Waste Heat Boiler system are Waste Heat Boiler 46-B101/201, and BFW pump 46-P-102A/B/C. Table 4-22 : Performance of Waste Heat Boiler 2-Oct-07
DESIGN
46-B-101
46-B-101/102
1 INLET GAS, Fuel Gas Flow, MMSCFD
1.55
1.77
Acid Gas Flow, MMSCFD
20.23
48.11
Permeat Gas Flow, MMSCFD
8.35
68.39
T out, F
376.00
416.00
O2, %
7.00
2.62
Excess Air, %
45.77
13.17
lb/hr
200,392.00
245,000.00
T in Economizer, F
200.00
251.00
T out Evaporator, F
347.00
375.00
P in Economizer, Psi
132.40
175.70
P out Evaporator, Psi
123.00
170.00
2 FLUE GAS
3 BFW
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4 PERFORMANCE Heat Release (LHV), MMBtu/hr
149.52
822.94
Heat Release (HHV), MMBtu/hr
164.41
Heat Loss (LHV), MMBtu/hr
29.91
Heat Loss (HHV), MMBtu/hr
43.92
Heat absorption (LHV), MMBtu/hr
119.60
Heat absorption (HHV), MMBtu/hr
120.49
Efficiency (LHV), %
79.99
no Dsg Eff
Efficiency (HHV), %
73.29
no Dsg Eff
CO2 Emission from fuel gas, lb/hr
29,070.86
no Dsg CO2
CO2 Emission from Acid gas, lb/hr
103,029.15
no Dsg CO2
CO2 Emission from Permeat gas, lb/hr
42,586.20
no Dsg CO2
Total CO2 Emission, lb/hr
174,686.21
no Dsg CO2
380.55
442.38
5 CO2 EMISSION
The above table shows that the WHB are operated at only 50 % load compare to design condition, and the calculated efficiency is 80%. The temperature in flue gas are lower than design condition and the excess air is higher than design. Table 4-23 : Performance of BFW Pump
DESCRIPTION
UNIT
specific gravity
46-P-102A
46-P-102C
Design
value
value
value
1.00
1.00
1.00
245.00
245.00
70.00
Temperature
F
suction pressure
psia
21.10
21.10
8.00
discharge pressure
psia
274.70
274.70
230.00
flow
GPM
380.00
380.00
528.00
Total head
ft
585.82
585.82
512.82
Electric motor power
HP
95.00
95.00
110.00
Mechanical work
HP
57.45
57.45
69.88
Efficiency
%
60.48
60.48
63.53
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Like Amine booster Pumps, the two BFW pumps were running within the specification, and the efficiency reached is accepted. This BFW pump is designed to run with 63.53% efficiency at 528 GPM flow rate. Actually, two pumps were running at same rate of flow (380 GPM) with 60.48% efficiency. 4.2.7. GAS TURBINE GENERATOR A. DESCRIPTION Electrical power is generated and distributed to provide the prower requirements for the gas plant and offsites. Electrical power Generator driven by Gas turbine generator, which gas supplied from HP (high pressure) fuel gas system. Three gas turbine are provided with two generator running and one on the standby mode. The design capacity of generator is 4500 kW each unit. The actual capacity on the field survey only about 2100 kW each turbine generator (45% of design capacity) and running two of three generators. Generator specification is power 4688, voltage 4160, freq 50 Hz, cos Q 0.85. The large motor (lean amine charge pump, WHB Blower, propane compressor) supply by 6600 volt and the other motors using 400 volts. B. PERFROMANCE Gas turbine generators at Utility system are 47-GTG-101A/B/C Table – 4.24 : performance of GTG 2-Oct-07 47-GT-101A
DESIGN
47-GT-101B
47-GT-101A/B/C
TURBINE Fuel gas : flow, MMSCFD
0.89
0.92
1.31
Temperature, F
0
0
900
O2, %
16
16
16
Excess Air, %
296
281
267
Turbine Eff, %
21
21
30
Btu/kwh
16,571
16,077
11,559
lb/hr
4,870
5,034
7,914
Power Output, KW
2,158
2,265
4,688
PF
0.81
0.83
0.84
Flue gas :
CO2 Emission GENERATOR
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V
4160
4160
4160
Frequency, Hz
50
50
50
The above table shows that GTG operated at 50 % load compare to design condition. The calculated efficiency is only 21 % compare to design which is 30 %. The decreasing of efficiency of GTG is caused by low load and will be impact the increasing of the heat loss, The heat rate of 47-GT-101A is 16,571 Btu/kwh, greather than design 16000 Btu/kwh but 47-GT-101B 16,077 Btu/kwh close to design. Table 4-25 : The design performance of GTG are as follows POWER
4500
4000
3500
3000
2500
2000
1500
1000
BTU/KWH
11600
12000
12600
13000
14000
16000
18700
25000
4.2.8. AIR COMPRESSOR A. OPERATION Instrument and utility air are supplied by the two 340 scfm, screw type compressor connectod in a lead-lag configuration. The compressed air is filtered and then dried in heatless adsorption type dries which are on automatic regeneration cycles. The instrument air compressor packages are provided with local electronic control panels. The instrument air receiver is normally operated between 110 and 120 psig. The utility air take-off is equipped with a shut off valves to prevent utility air usage from drawing down the instrument air pressure. B. PERFORMANCE There are three compressors Atlas Copco GA 75 , 51-A-101A /B/C with design capacity is 340 SCFM, the performance of each equipment are as follows, Table 4-26 : Performance of air compressor : UNITS
DESIGN
ACTUAL
SUCTION PRESS
PSI
14.70
14.70
DISCHARD PRESS.
PSI
182.00
132.30
COMPRESS AIR FLOW
SCFM
340.00
257.45
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KW
ACTUAL PERFORMANCE
Page 85 of 109 72.60
44.17
0.20
0.20
The above table shows that the compressor is operated at low load. performance can not be evaluate accurately because no flow meter of air
The
4.2.9. ELECTRICAL MAP CENTRAL GRISSIK GAS PLANT Electric map for Central Grissik Plant is like the one for Suban Gas plant. It is derived from single line diagram, and intend to get a closer and clear point of view to one that need brief description on power consumption at each process. It Emphasize the voltage, and power required for each equipment. The power mentioned at each equipment is the power in normal design condition. A. Amine System
4.16 KV 25-P-102 A/B/C Amine Charge pump A/B/C 2250 HP x3
480 V 25-EM-103 A-M 25-PM-101 A/B/C Lean amine booster pump A/B/C Lean Amine cooler fan A-M 37.3 KW x13 200 HP x3
25-EM-201 A-M Regenerator reflux condenser fan A-M 29.8 KW x13
25-PM-105 Amine Transfer pump 9 HP
25-PM-104 Amine Sump pump 15 HP
25-EM-203 A-M Lean Amine cooler fan A-M 37.3 KW x13
25-EM-101 A-M Regenerator reflux condenser fan A-M 29.8 KW x13
25-AM-101/102 25-PM-203A/B Anti foam injection pump Regenerator reflux pump A/B 7.50 HP x2 2 HP x2
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B. Propane Chiller System 4.16 KV
30-K-101 A/B Propane Compressor A/B 350 HP x2
480 V 30-K-101A/B-PM1 30-PM-103 Propane Compr. A L.O. pump motor Propane Transfer pump 5 HP x2 3 HP
30-K-101A/B-KM1 Propane Compr. A/B L.O. cooler fan 5 HP x2
C. Depropanizer and Condensate Stabilization System
480 V
30-PM-102 30-PM-101 Depropaniser reflux pump Depropaniser feed pump 3.5 HP
5 HP
30-EM-105 A/B 30-E-104 Depropaniser reboiler heater Propane condenser fan A/B 22.3 KW x2 69 KW
35-PM-102 A/B Condensate shipping pump A/B 75 HP x2
D. Dehydration System 480 V 41-PM-101 41-PM-102/2020/302 A/B Glycol transfer pump Glycol circulation pump 1.74 HP 25 HP x6
E. Incinerator/Heat recovery System
4.16 KV 46-K-101/201 Inc. Blower train A/B 400 HP
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F. BFW steam and Condensate System 480 V 46-PM-102 A/B/C BFW pump A/B/C 150 HP
46-PM-103 A/B Condensate pump A/B 25 HP x2
46-EM-101 A/B Excess steam condenser fan A/B 22.3 HP x2
G. Flare and Air compressor System 480 V 48-PM-101 A/B Flare KO drum pump A/B 3 HP x2
51-AM-101 A/B Instr. Air compressor A/B 125 HP x2
51-AM-101 A/B -2 Instr. Air compressor A/B cooler fan 4 HP x2
H. Utility System
480 V 55-PM-201 A/B 54-PM-201 A/B Utility water pump A/B Portable water pump A/B 15 HP x2 7.5 HP x2
4.3.
53-PM-201 A/B Softened water pump A/B 7.5 HP x2
FINDINGS AND RECOMMENDATION
1. Instrumentation and Metering Based on the site survey founded that many metering and instrument are not work properly. Findings and recommendations of metering and instrumentation at Grissik Central Gas Plant are as follows :
Equipments 1.
WHB
Findings
There are unbalance between BFW flow and steam flow that will impact the direct method efficiency calculation is not accurate. Oxygen analyzer not work properly ( direct measurement = 7 % , on
Recommendations
Need to calibrate meter of steam and BFW
Need to install sampling point to measure Boiler water quality and control the blow down
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line analyzer = 14 %)
2
Glycol Regen Heater
3
2.
&
GTG
No Sampling point for water quality at steam drum
No meter fuel gas at the heater
need to install fuel gas meter
The position of flue gas sampling point is far from platform
need to install sampling line of flue gas close to the platform
There are no flow meter of fuel gas in each GTG.
Need to install flow meter of fuel gas
Need to install sampling line of flue gas for each GTG
4
Propane Comp
No continue record of electric consumption for motor compressor
Need to continously
5
Electric Distribution
No continue recorded for electric distribution
Need to record electric distribution (4160 line) at daily records
records
Waste Heat Boiler
Calculation result of WHB : EFFICIENCY
HEAT ABSORB
CO2 EMISSION
%
MMBtu/hr
Lb/hr
DESIGN
N/A
442.38
N/A
46-B-101
79.99
119.60
174,686.21
46-B-102
OFF
OFF
OFF
W H B - INCENERATOR 46-B-101
Finding :
WHB is operated at high excess air (77 %) compare to the design figure which is 27 % excess air. The efficiency is 80 %
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WHB is operated at low load ( 50 % load)
Recommendation :
WHB should be operated close to the design excess air
3. Heater Calculation result of heater : EFFICIENCY %
HEAT ABSORB MMBtu/hr
CO2 EMISSION Lb/hr
GLYCOL HEATER : 41-H-101 DESIGN 41-H-101 41-H-201
84.91 84.91
0.91 0.91
191.42 191.42
REG GAS HEATER : 21-H-101/201 DESIGN 21-H-101 21-H-201
74.62 74.65 OFF
11.06 5.75 OFF
2,651.23 1,376.93 OFF
Finding : The heater are operated at low load (50 % load) 4. GTG Calculation result of GTG : EFFICIENCY % GAS TURBINE GENERATOR DESIGN 47-GT-101A 47-GT-101B 47-GT-101C
29.52 20.59 21.23 OFF
HEAT RATE BTU/KWH
11,558.78 16,571.34 16,077.04 OFF
BHP KW
CO2 EMISSION Lb/hr
4,687.50 2,158.33 2,264.58 OFF
Findings : GTG are operated at lower load is around 50 % compare to design, but the performance ( heat rate ) are still close to design at low load
7,914.10 4,869.94 5,034.10 OFF
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5. Propane Comp Calculation result of Propane Compressor : POWER REQUIRED, KW DESIGN 30-K-101A
242.17 101.64
ACTUAL POWER, KW
260.00 110.00
PROPANE FLOW
COP
14,000.00 7,191.72
3.00 2.87
Findings : Based on the actual data, the refrigeration load is only 50 % compare to design condition, but the COP is 2.87 compare to design COP is 3. It means that the compressor is still in good condition 6. Gas Chiller Calculation result of gas chiller : UNITS GAS INTAKE TEMP.AT EVAP. GAS OUTPUT TEMP.AT EVAP. SALES GAS FLOW CONDENSATE FLOW HEAT RELEASE TOTAL POWER C.O.P
DESIGN
DEG F DEG F MMCFD BBL/D MMBtu/hr KW
GAS CHILLER
58.00 45.00 100.00 700.00 2,645,934.62 260.00 2.98 (Calculated)
Findings :
the temperature indicator inlet and outlet are still in good conditions
COP at gas chiller is 2.24 compare to design 2.98
57.00 45.00 39.00 700.00 841,348.85 110.00 2.24
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7. Air cooler Calculation result of coolers are as below:
No.
COOLER
HEAT DUTY (MMBTU/HR)
1.
Amine Regen Reflux Cooler 25-E-101 55.70 25-E-201 OFF Lean Amine Cooler 25-E-103 62.22 25-E-203 53.47 Stab. Condensate Cooler 35-E-101 0.72 Propane Condenser Compressor Cooler 30-E-105 3.09 Propane Ovhd Cooler 30-E-103 OFF
2.
3. 4. 5.
HEAT TRANSFER RATE
ELECTRIC/HEAT DUTY
(BTU/HR.FT2.oF)
(%)
3.57 OFF
1.60% OFF
2.06 1.88
1.85% 2.34%
5.03
8.85%
2.89
1.63%
OFF
OFF
Findings :
Power rated required for drive motors of fan coolers are below 1% - 2% due to their heat duties, except for Lean Amine 25-E-203 and Condensate cooler (25-E-101). This case indicate that power consumption of these coolers more waste energy (less efficiency).
Recommendations :
Need to check the cooler system of Lean amine cooler, because at the plant survey, they have high power consumption although the capacity of heat load only a half than design.
Need to check again the properties of amine used in operation, because it can effect the calculation performance of cooler and exchanger system in amine system.
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8. Heat Exchanger Calculation result of heat exchangers are as below: No.
HEAT EXCHANGER
1.
HEAT DUTY
DIRTY FACTOR
(MMBTU/HR)
HEAT TRANSFER RATE (BTU/HR.FT2.oF)
ACTUAL
DESIGN
ELECTRIC/ HEAT DUTY (%)
21-E-101
0.97
6.90
0.063
0.002
-
21-E-201
OFF
OFF
OFF
OFF
OFF
21-E-102
4.67
4.46
0.005
0.002
-
21-E-202
OFF
OFF
OFF
OFF
OFF
Rich/Lean Amine Exchanger 25-E-104A/B
53.58
N/A
N/A
N/A
-
25-E-204A/B
OFF
OFF
OFF
OFF
OFF
Rich/Lean Glycol Exchanger 41-E-101
1.40
104.88
0.002
0.001
-
41-E-201
1.73
117.99
0.001
0.001
-
41-E-301
1.67
111.25
0.001
0.001
-
Gas-Gas Dew Point Control HE 30-E-101
3.16
0.29
0.09
0.10
-
184.59 OFF 0.70
132.16 OFF 6.52
0.002 OFF 0.001
0.001 OFF 0.001
OFF -
0.14
N/A
N/A
N/A
102.32%
Gas-Gas HE in TSA unit Regen HE:
Cooler HE:
2.
3.
4.
5.
Amine Regen Reboiler 25-E-102 A-D 25-E-202 A-D Stabilizer Reboiler 35-E102 Depropanizer Reboiler 30E-105
6. 7.
Findings :
Entirely, the performance of heat exchangers in Grissik plant still in good condition, except for Gas/GAs Exchanger in TSA unit is needed to check again for the fouling condition, because it’s dirty factor have higher than their specification (design).
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9. Gas Pretreatment & Membrane system CALCULATION OF MEMBRANE SYSTEM Membrane Separation Rate Design Value of Membrane Separation
0.321556 lbmole/ lbmole 0.511022 lbmole/ lbmole
HYDROCARBON SLIP Rate Design Value of Hydrocarbon Slip Rate
0.030709 lbmole/ lbmole 0.063241 lbmole/ lbmole
Findings :
The Thermal swing adsorber (TSA) system running on good condition, because the C6+ concentration at the feed gas to membrane is 29 ppm compare to the design is 39 ppm.
The membrane system separation only give separation rate is 32% compare to the design 50% of CO2 feed, so the CO2 content in gas to contactor still high than design value.
Recommendation :
Need to check again the membrane module system to upgrade the separation rate.
10. Amine System Findings :
The absortion rate capacity of amine contactor is only 38% refer to the design capacity rate. This case caused by the flowrate of gas processing capacity of lean amine only 40% than design.
Recommendation :
Need to operate full gas processing capacity to increase absorption rate in amine contactor due to reduce the energy consumption in amine system
11. Energy Conservation a. Energy Losses : Based on heat balance calculation, energy losses from high temperature flue gas (more than500deg F) at Grissik is coming from Stack of GTG. Total losses is 57,821,543 Btu/hr.
STACK LOSS, Btu/hr
TEMP, Deg F
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GTG 247-GT-201A
30,471,332
949
247-GT-201B
27,350,211
967
247-GT-201C
0
0
57,821,543
958
TOTAL
Actually, by utilizing economizer with stack temperature around 500 deg F, this Fluegas losses can be used to generate saturated steam about 28,000 lb/hr.
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b. Potential Saving : Based on the evaluation, shows that the potential saving are coming from :
Optimize operation of WHB by reducing excess air (7 % O2 to 3% O2) increase efficiency aroumd 4 %, that will reduced LP fuel consumption to 0.06 MMSCFD
Utilized flare gas that will reduced fuel consumption to 1.0 MMSCFD
Energy Conservation Opportunities :
Optimized operation of GTG can be implemented by load shading
Optimized operation of Heater and utilized flare gas can be implemented by installing booster compressor to compress gas up to 180 psig. This fuel can be used for Gas turbine and in turn it will reduce HP Fuel consumption. The simple calculation are as follows :
WHB-saving, MMSCFD
0.06
, US $/Year
76,725.00
Flare Gas-saving, MMSCFD
1.00
, US $/Year
1,237,500.00 Total, MMSCFD
1.06
, US $/Year
1,314,225.00
*Cost to install the system for recovery gas which includes : gas compressor, KO Drum, Instrumentations , US $ Operation and Maintenance Cost , US $/year Net income , US $/Year
Estimated payback period to install the system , Years
3,000,000.00
120,000.00 1,194,225.00
2.51
* = refer to Beak Pacifik Report - Energy Audit at Cilacap Refinery Complex (Beak Pacific Inc. , Vancouver, Canada)
c. Emission Reduction Potentials CO2 emission at suban gas plant is 182,886 lb/hr. its come from combustion of fuel gas at flare gas, heater, WHB and GTG. Optimized operation and utilized flare gas can reduce CO2 emission around 5 %
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CO2 reduction, lb/hr utilized flare gas
8,507.79 Total
8,507.79
Utilized flare gas will reduce CO2 emission , %
5%
12. Reporting system Findings :
Existing daily report just for production activity it does not cover data for plant performance evaluation purpose
No data acquisition and evaluation based on daily log sheet .
Important data for plant performance not cover in daily log sheet
Recommendation :
Daily reporting must cover production activity and plant performance indicator
Regular summary of log sheet regarding plant performance should be evaluate.
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V. ENERGY ASSESSMENT AT RAWA PLANT 5.1 5.1.1.
OIL
GENERAL PLANT OPERATION AND PERFORMANCE PLANT OPERATION
There are wells at ConocoPhillips South Sumatra area that contents oil in significant amount and high gas concentration. Rawa plant is designed to process this oil, and re inject the gases to the injection wells. High-pressure oil & gas came firstly from wells entering the plant via manifold, before entering the production processes. The first process is High-pressure separator (HP separator). Oil, MP Gas and Water is separated in this process. MP gas (450 psig) leave the top separator and water leave the bottom of the separator and then store it in the production water tank before send to Central Ramba. Oil & LP gas mixture goes to medium pressure (MP) separator. In MP Separator, Oil & HP gas is separated. Oil is stored to the crude oil tank before ship to Plaju. LP Gas (50 psig) compressed by LP Gas compressor (gas engine) to raise it the pressure until 450 psig. MP gas from HP separator mix with MP Gas from LP Compressor and then the HP Compressor driven by gas turbine to rise the pressure until 1200 psig. Water content in HP Gas is reduced by glycol system before injected to the wells. The design of HP Compressor is 45 MMSCFD and about 1 MMSCFD of process gas used for fuel. The simplified process flow diagram of Rawa field is shown at diagram in figure 1.1
MP Gas
5 HP Compressor
Oil wells
2
1 HP Separator
Gas Scrubber
MP Separator
3
4 Prod water tank
To Ramba
LP Compressor
4 Oil Send to Plaju and Bentayan
Figure 5.1. (simplified)
Rawa prod. Block diagram
Injection To wells Glycol System
Final Report
ID-N-GN-00000-00000-00068
Energy Management Audit / Assessment for PSC Corridor ConocoPhillips Indonesia
Page 98 of 109
Data from production records taken from 1-10 Aug 2007 at table 1 shows that oil extracted from wells is about 300-320 barrels/day (0.001%) and water produced is 1500-1600 (0.003%). About 21 MMSCFD gas derived is re injected to injection wells while the other product, i.e. fuel gas, is sent to Ramba station. Table -5.1 : Oil Production Data
5.1.2.
GENERAL PERFORMANCE EVALUATION
The Energy Source of Rawa oil Plant is LPgas used for gas turbine compressor (LP and HP) and Glycol Regenerator which comes from LP Separator. LP Compressor driven by gas engine to increase the LP Gas pressure from 60 psi to 450 psi and HP Compressor driven by gas turbine to increase the MP gas from LP Compressor and HP Separator to 1200 psi. Fuel flow meter only for total consumption. There is no flow meter for each consumers. The total consumption is 0.7 – 1.1 MMSCFD Rawa oil processing plant doesn't have electric power generation systems inside the plant itself. Electric power derived from Ramba power plant via medium voltage lines, 11KV, 3, 50 Hz. Incoming power line then is stepped down by a transformer to 380V/220V, 3, and in turn, this voltage system is applied to all the electrical equipments and machines inside the plant. There is no KW Meter in main panel. The estimate load is about 150 KW. For emergency purposes, there is a diesel fueled electric generator (380V, 3, 50 Hz) that has capacity of 505 KVA. This generator set needed extra maintenance due to this machine is of the old type, and have been used over a long period of time.
5.2
PERFORMANCE EVALUATION OF MAIN EQUIPMENT
The main equipment at rawa oil plant are . HP Compressor 5000-PK-100 , Compressor 5000-PK-101 and Glycol Reboiler 3600-HT-103 The performance of HP and LP Compressor are as follows :
LP
Final Report
ID-N-GN-00000-00000-00068
Energy Management Audit / Assessment for PSC Corridor ConocoPhillips Indonesia
Page 99 of 109
HP Compressor 5000-PK-100 Table -5.2 : Performance of HP Compressor 5000-PK-100 UNITS
INJECTION GAS ABSL.SUCTION PRESSURE
(Ps)
ABSL. DISCHARED PRESSURE (Pd)
POWER REQUIRE
ACTUAL
DESIGN
MMCFD
39.20
45.00
PSIA
455.00
515.00
PSIA
1,165.00
1,465.00
HP
2,860
3,525
Injection gas flow at actual condition is 39.20 MMSCFD (87 % load) compare to design (45 MMSCFD) and power require is 2860 HP compare to 3525 HP Table -5.3 : Performance of turbine 5000-PK-100
A
21-Dec-07
DESIGN
HP Turbine 5000PK-100
HP turbine 5000PK-100
TURBINE Fuel gas : flow, MMSCFD
0.85
0.89
Temperature, C
1,062
900
O2, %
15
16
Excess Air, %
234
279
Eff, %
22
27
Btu/BHP
11,460
9,392
Flow, lb/hr
2,217
2,450
Power Required, KW
2,134
2,630
, HP
2,860
3,525
Flue gas :
CO2 emission : B
COMPRESSOR
Turbine is operated at 72 % load (2860 HP) compare to design (3525 HP) and heat rate is 11.460 Btu/HP compare to the design heat rate is 10500 Btu/HP.
Final Report
ID-N-GN-00000-00000-00068
Energy Management Audit / Assessment for PSC Corridor ConocoPhillips Indonesia
Page 100 of 109
Table -5.4 : Design performance of turbines POWER,HP
4000
3500
3000
2500
2000
1500
1000
BTU/BHP
9500
9700
10500
11000
12000
12700
14000
LP Compressor 5000-PK-101 Table -5.5 : Performance LP Compressor 5000-PK-101 are as follows
UNITS INJECTION GAS
ACTUAL
DESIGN
MMCFD
6.00
15.00
PSIA
75.00
75.00
ABSL. DISCHARED PRESSURE (Pd)
PSIA
445.00
450.00
FUEL CONSUMPTION
MCFD
250.00
400.00
HP
533.05
1,439.09
19,541.46
11,581.36
ABSL.SUCTION PRESSURE
POWER REQUIRE ENERGY INTENSITY
(Ps)
Btu/HP
LP compressor is operated at low load (less than 40 %) compare to design it will impact the energy intensity very high (19,541 BTU/HP compare design value 11,581 BTU/HP)
5.3
FINDINGS AND RECOMMENDATION
Findings : A. Instrumentation
no flow gas meter for each gas consumer,
no control monitoring system that can be used to monitor the operation of the compressor from control room.
No meter indicators for electric equipments.
B. Compressor
Compressors is operated at low load for LP (less then 40%)
Final Report Energy Management Audit / Assessment for PSC Corridor ConocoPhillips Indonesia
ID-N-GN-00000-00000-00068 Page 101 of 109
HP compressor is operated 70% load compare to design, the heat rate is higher then design heat rate at 70 % load.
LP compressors shut down frequently and causing increase of flare gas from 1 MMSCFD to 4-9 MMSCFD.
Final Report
ID-N-GN-00000-00000-00068
Energy Management Audit / Assessment for PSC Corridor ConocoPhillips Indonesia
Page 102 of 109
VI. PERFORMANCE MONITORING INDICATOR 6.1. EQUIPMENTS 6.1.1. Fired Heater Function : converting energy from fuel gas into thermal in order to increase the temperature of process fluid Key Performance Indicator : Efficiency which is consist of combustion efficiency and heat transfer efficiency Variable should be Measured :
% O2 in flue gas
Stack Gas Temperature
Ambient Temperature
Fuel gas flow, composition
Fuel gas heating value
Spread sheet : See Appendix no.6.1 6.1.2. Waste Heat Boiler Function : converting energy from fuel gas and permeat gas into thermal in order to produce steam and oxidize H2S from acid gas Key Performance Indicator : Efficiency which consist of combustion efficiency and Heat transfer efficiency Variable should be Measured :
% O2 in flue gas
Stack Gas Temperature
Ambient Temperature
Flow and composition of fuel gas, permeat gas and acid gas
Heating value of fuel gas, permeat gas and acid gas
Spread sheet : See Appendix no.6.2
Final Report
ID-N-GN-00000-00000-00068
Energy Management Audit / Assessment for PSC Corridor ConocoPhillips Indonesia
Page 103 of 109
6.1.3. Gas Turbine Generator Function : converting energy from fuel gas to mechanical energy to produce electricity Key Performance Indicator : Efficiency which is consist of gas turbine efficiency and generator efficiency Variable should be Measured :
Fuel gas flow (input)
Fuel gas heating value (LHV)
Generator Output
Oxygen content in flue gas
Flue gas temperature
Spread sheet : See Appendix no.6.3 6.1.4. Gas Turbine Compressor Function : converting energy from fuel gas to mechanical energy to compress sales gas Key Performance Indicator :
Efficiency which consist of gas turbine efficiency and compressor efficiency
Energy Intensity which is representing by fuel gas divided by mechanical energy to compress sales gas
Variable should be Measured :
Fuel gas flow (input)
Fuel gas heating value (LHV)
Oxygen content in flue gas
Flue gas temperature
Suction and discharge pressure of sales gas
Flow of sales gas
Spread sheet : See Appendix no.6.4
Final Report
ID-N-GN-00000-00000-00068
Energy Management Audit / Assessment for PSC Corridor ConocoPhillips Indonesia
6.1.5. Air Compressor Function : converting energy from electricity to compress air Key Performance Indicator : Actual power / Qs x ((Pd/Ps)^0.2857 – 1) Note : Qs = air flow
Variable should be Measured :
Electricity power (input)
Pressure of compressed air
Spread sheet : See Appendix no.6.5 6.1.6. Propane compressor Functions : to evaporate refrigerant and to condense refrigerant vapor Key Performance Indicator : Coefficient of Performance (COP) Variable should be Measured :
Electricity power (input)
Evaporation Temperature
Condensing Temperature
Spread sheet : See Appendix no.6.6 6.1.7. Pumps Functions : to transfer or to lift up the liquid Key Performance Indicator : Efficiency which consist of pump efficiency Variable should be Measured :
Electricity power (input)
Liquid flow
Suction and discharge pressure
Spread sheet :
Page 104 of 109
Final Report
ID-N-GN-00000-00000-00068
Energy Management Audit / Assessment for PSC Corridor ConocoPhillips Indonesia
Page 105 of 109
See Appendix no.6.7 6.1.8. Air Cooler Functions : to cooling the fluid or to condense the vapor Key Performance Indicator : Overall heat transfer coefficient (U) Variable should be Measured :
Electricity power (input)
Liquid flow
Temperature and Pressure of fluid inlet and outlet
Composition of fluid
Spread sheet : See Appendix no.6.8 6.1.9. Heat Exchanger Functions : to transfer heat from high temperature to low temperature of fluid Key Performance Indicator : Overall heat transfer coefficient (U) Variable should be Measured :
Fluid flow
Temperature inlet and outlet of hot side and cold side
Operating Pressure of hot side and cold side
Composition of fluid
Spread sheet : See Appendix no.6.9
Final Report
ID-N-GN-00000-00000-00068
Energy Management Audit / Assessment for PSC Corridor ConocoPhillips Indonesia
6.2. SYSTEM 6.2.1. TSA System Functions : to reduce heavy hydrocarbon content of feed gas Key Performance Indicator :
Adsorption Rate
TSA Regeneration Rate
Variable should be Measured :
Feed gas flow
Temperature of feed gas
Pressure inlet and outlet gas
Composition of feed gas and outlet gas
Spread sheet : See Appendices no.6.10 6.2.2. Membrane System Functions : to reduce CO2 content of feed gas Key Performance Indicator :
Membrane separation rate
HC Slipped rate
Variable should be Measured :
mole CO2 in Permeate Gas
Mole CO2 in Feed Gas
mole HC in Permeate Gas
Mole HC in Feed Gas
Spread sheet : See Appendices no.6.11 6.2.3. Amine System Functions : to reduce acid gas (CO2 & H2S) content of treated gas
Page 106 of 109
Final Report
ID-N-GN-00000-00000-00068
Energy Management Audit / Assessment for PSC Corridor ConocoPhillips Indonesia
A. Amine Contactor Functions : to absorb acid in treated gas by amine liquid Key Performance Indicator:
Absorbtion Rate
Variable should be measured:
mole-CO2 absorbed
Mole pure lean amine
Spread sheet : See Appendix no.6.12 B. Amine Regenerator Functions : to desorb/strip acid in rich amine by heating Key Performance Indicator:
Amine Regeneration Rate
Variable should be measured:
CO2 content in lean amine and CO2 content in acid gas flow
Quantity of steam or fuel gas consumption
Operating temperature and pressure of regenerator
Spread sheet : See Appendix no.6.13 6.2.4. Dehydration System Functions : to remove moisture in treated gas by glycol Key Performance Indicator:
Absorbtion Rate
Glycol Regeneration Rate
Variable should be measured:
Flow of gas and glycol
water content inlet and outlet of treated gas
water content in lean glycol
Operating temperature and pressure of contactor
Spread sheet :
Page 107 of 109
Final Report
ID-N-GN-00000-00000-00068
Energy Management Audit / Assessment for PSC Corridor ConocoPhillips Indonesia
Page 108 of 109
See Appendix no.6.14
6.2.5. Dew Point Control System A. Gas Chiller Functions : chilling treated gas Key Performance Indicator:
COP (heat released by fluid divide by power of compressor unit)
Variable should be measured:
Flow of sales gas and condensate
Composition of sales gas and condensate
Temperature inlet and outlet of chiller
Spread sheet : See Appendices no.6.15 B. Low Temperature Separator Functions : to separate of sales gas and condensate. Key Performance Indicator: Percentage of condensate content in sales gas compared to design value Variable should be measured:
Flow of sales gas and condensate
Composition of sales gas and condensate
Operating Temperature and Pressure of separator
Spread sheet : See Appendices no.6.16 6.2.6. Condensate Stabilizer Functions : to remove light hydrocarbon from condensate. Key Performance Indicator:
Yield of Stabilization
Stabilizer Performance
Variable should be measured:
Flow of raw condensate
Flow of treated condensate
Final Report
ID-N-GN-00000-00000-00068
Energy Management Audit / Assessment for PSC Corridor ConocoPhillips Indonesia
Composition of condensate
Flow of steam
Operating Temperature and Pressure of column
Spread sheet : See Appendix no.6.17 6.2.7.
Depropanizer
Functions : to produce propane. Key Performance Indicator:
Yield of Stabilization
Depropanizer Performance
Variable should be measured:
Flow of feed to column
Flow of propane product
Electric consumption
Operating Temperature and Pressure of column
Spreadsheet: See Appendix no.6.18
Page 109 of 109
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