A PROPANE RECOVERY PLANT
View: Process Flow Diagram
View: Simulation Results
This example is the final one included in the XPSIM – Reference Manual.
The process flow diagram shows a propane recovery plant which uses a turbo-expander to cool the inlet gas together with multi-stream heat exchanger.
The process is designed to recover propane as well as the C4-C5 fraction from a natural gas feed stream.
The deethanizer column uses a cold-box E-1 as side reboiler.
The maximum amount of ethane allowed in the bottom product is specified at 2 percent molar.
The feed stream is named FEED, its temperature is 115°F and the pressure is 800 psia.
Its composition is defined as follows:
|
No |
Components |
Molar flow rate, lbm/h |
|
1 |
N2 |
151.17 |
|
2 |
CO2 |
44.33 |
|
3 |
METHANE |
8545.25 |
|
4 |
ETHANE |
868.88 |
|
5 |
PROPANE |
83.964 |
|
6 |
IBUTANE |
58.33 |
|
7 |
BUTANE |
114.92 |
|
8 |
IPENTANE |
18.92 |
|
9 |
PENTANE |
38.83 |
|
10 |
HEXANE |
24.63 |
|
11 |
HEPTANE |
4.38 |
The Soave-Redlich-Kwong (SRK) is used for vapor-liquid equilibrium and the Lee-Kesler (LK) for enthalpy, entropy and density calculations.
In addition of the bottom composition specification two other temperature specifications are used to properly operate the deethanizer.
The first one sets the temperature of the condenser at -73°F, while the second assure that the operating temperature of the side reboiler (located on tray 7) is constrained at 25 °F.
The generated keyword input file is extremely compact, readable and self-explaining.
<XPSIM> ...generated by XpsimWin v.1.06 ...
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RUN ID=TTEX01 CUSTOMER=STAFF PROJECT='TEX PLANT TEST'
DESC TEST CALCULATION - TURBOEXPANDER PLANT
DESC PROPANE RECOVERY
DIMENSION ENG
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System Data
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CHEMCOMP N2 / CO2 / METHANE / ETHANE / PROPANE / BUTANE / IBUTANE / +
PENTANE / IPENTANE / HEXANE / HEPTANE
THERMSET UID=M1
METHODS K=SRK HV=LK HL=LK SV=LK SL=LK CPV=LK CPL=LK DV=LK DL=LK IV=LK +
VISV=IDEAL VISL=IDEAL THCV=IDEAL THCL=IDEAL SURT=IDEAL
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Flowsheet Data
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STREAM=FEED TEMP=115. PRES=800.
COMP 151.17 / 44.33 / 8545.25 / 868.88 / 483.96 / 58.33 / 114.92 / +
18.92 / 38.83 / 24.63 / 4.38
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STREAM=S108 TEMP=-25. PRES=750. RATE(M)=10353.58 REFSTR=FEED
NAME S148 'PROPANE PRODUCT' / S119 'ETHANE RICH PRODUCT' / S114 +
'EXPANDER LIQUID PRODUCT'
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FLASH IN FEED OUT S102(V) S101(L) UID=V-1
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FLASH IN S108 OUT S109(V) S110(L) UID=V-2 +
DESC='MEDIUM PRESSURE FLASH'
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EXPANDER IN S109 OUT S113(V) S114(L) UID=EX-1 DESC=TURBOEXPANDER
CALC POUT=152 EFF=80.
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COLUMN IN S110 S114 OUT S143 S148 UID=C-1 DESC='DEETHANIZER COLUMN '
PARA TRAY=14 CON REB NITER=5
FEED STR=S110 TRAY=7
FEED STR=S114 TRAY=3
DRAWOFF STR=S143 TRAY=0 PHASE=VAP
DRAWOFF STR=S148 TRAY=15 PHASE=LIQ RATE(VAR)=688.
HEAT TRAY=0 VAR
HEAT TRAY=7 VAR
HEAT TRAY=15 VAR
PUMPAR FROM=8 TO=7 RATE(VAR)=600. PHASE=VAP TOTAL
PSPEC PTOP=134. TRAY=0 DP=8 / TRAY=1 DP=.1
PROFILE TRAY=0 LIQ=224. TEMP=-73 / TRAY=2 LIQ=180. TEMP=-47. / TRAY=3 +
LIQ=900. TEMP=-40 / TRAY=7 LIQ=1240. TEMP=26. / TRAY=8 / TRAY=14 +
LIQ=1406 TEMP=95. / TRAY=15 LIQ=704. TEMP=106
SPEC TEMP=-73. TRAY=0
SPEC TEMP=25. TRAY=7
SPEC FRAC(M)=.02 STR=LDRA:15 COMP=ETHANE
PLOT PROFILE
PRINT TRACE=PART LKEY=METHANE,ETHANE HKEY=PROPANE,PENTANE FORMAT=2 +
TRAY=2 PROP=2 MFRAC WFRAC WRATE
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HEATEXCH IN S113 OUT S116 UID=CONDENSR
HOT OUT=S116 FEED=S113 PRES=134.
DUTY DUTY=1 RATIO REFUOP=C-1 RHXID=0
HCURVE PLOT
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MIXER IN S116 S143 OUT S117 UID=MX-1
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HEATEXCH IN S102 S117 OUT S108 S119 UID=E-1 +
DESC='COLD-BOX EXCHANGER '
DUTY DUTY=1 RATIO REFUOP=C-1 RHXID=7
HOT OUT=S108 FEED=S102 PRES=750.
COLD OUT=S119 FEED=S117 TEMP=105. PRES=118.
HCURVE PLOT
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Recycle Data
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SOLUTION NITER=10 NULLREC
ACCEL METHOD=WEGS START=5 FREQ=3 MINI=-4. MAXI=0.0
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Output Data
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PRINT FORMAT=2 WRATE MFRAC WFRAC MBAL STRSEQ=ALPH
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END