DEEP SEA GAS TRANSFER LINE
View: Process Flow Diagram
View: Simulation Results
The feasibility of gas transfer through a deep-waters using a very long sealine is simulated.
The feed stream is GASIN, it is received at battery limits at 50°C and 90 bar.
Feed
gas composition is shown on next table:
|
No |
Components |
Molar composition, % |
|
1 |
H2O |
0.0090 |
|
2 |
N2 |
0.19 |
|
3 |
CO2 |
0.21 |
|
4 |
METHANE |
94.89 |
|
5 |
ETHANE |
3.05 |
|
6 |
PROPANE |
1.04 |
|
7 |
IBUTANE |
0.19 |
|
8 |
BUTANE |
0.26 |
|
9 |
IPENTANE |
0.07 |
The feed gas is then compressed at 250 bar using a centrifugal compressor. Its polytropic efficiency is assumed 78%.
The gas discharged by the compressor is then cooled at 50°C before entering the sealine.
Thermodynamic and transport property models
For this calculation the selection of a reliable model for the calculation of gas viscosities at very high pressure is fundamental. Due to this reason the Ely-Hanley model is used.
A number of graphs are generated by XPSIM during the simulation.
Among them two are selected and presented here:
· pipeline elevation-distance profile
· pipeline pressure and temperature profile
The simulated condition of the gas at arrival (GASOUT) are shown hereunder.
* STREAM 'GASOUT '
- Temperature 3.632 CENT - Pressure 106.3840 BAR
Phase VAPOUR
Molar Flow Rate KMOL /HR 41005.295
Weight Flow Rate KG /HR 700000.000
Molar Fraction 1.000000
Weight Fraction 1.000000
Molecular Weight 17.0710
Std Vap Vol Rate N-CUMT /HR 969563.7814
Act Volume Rate CUMT /HR 6679.4876
Enthalpy M-KJ /HR -130125.0732
Spec. Enthalpy KJ/KG -185.927
KJ/KMOL -3173.949
Gross H.of comb. KJ/KMOL 932528.175
KJ/KG 54626.562
Net H.of comb. KJ/KMOL 841087.939
KJ/KG 49270.085
Spec. Heat Cap. KJ/KG-C 3.559379
KJ/KML-C 60.762043
Spec. Entropy KJ/KG-C 8.3949
KJ/KML-C 143.3099
Compressibility 0.752911
Density KG/CUMT 104.7985
Isentr. Exponent 1.330624
Viscosity CP 0.1471E-01
Thermal Conduct. W/MC 0.049045
Reference Gas Status - Temperature 15°C - Pressure 1 atm
----- TOTAL PHASE -----
No Components Mol. Rate Mol. Fr Wt. Rate Wt. Fr.
KMOL/HR KG /HR
1 WATER 3.694 0.000090 66.563 0.000095
2 NITROGEN 77.981 0.001902 2184.248 0.003120
3 CARBON DIOXIDE 86.190 0.002102 3793.202 0.005419
4 METHANE 38945.365 0.949764 624683.381 0.892405
5 ETHANE 1251.801 0.030528 37641.654 0.053774
6 PROPANE 426.843 0.010409 18823.801 0.026891
7 ISOBUTANE 77.981 0.001902 4532.257 0.006475
8 BUTANE 106.711 0.002602 6202.035 0.008860
9 ISOPENTANE 28.730 0.000701 2072.859 0.002961
*** TOTAL *** 41005.295 1.000000 700000.000 1.000000
<XPSIM> ...generated by XpsimWin v.1.06 ...
*
RUN ID=SEALINE CUSTOMER=STAFF PROJECT='DEEP SEA CROSSING'
DESC DEEP SEA PATH - FEASIBILITY ANALYSIS
DESC PRESSURE AND TEMPERATURE PROFILE
DESC NOMINAL DIAMETER 28 inches
DIMENSION INPUT SI PRES=BAR VREF=4
*
*
System Data
*
*
CHEMCOMP H2O / N2 / CO2 / C1 / C2 / C3 / IC4 / NC4 / IC5
THERMSET UID=M1
METHODS K=SRK HS=LK CP=LK D=LK IV=LK TRAN=ELYHAN SURT=IDEAL
REGION PHASE=CRIT
WOPT K=2
*
*
Flowsheet Data
*
*
*
STREAM=GASIN TEMP=50 PRES=90 RATE(W)=700000 XBASIS=M
COMP H2O:0.0090 / N2:0.19 / CO2:0.21 / C1:94.89 / C2:3.05 / C3:1.04 / +
IC4:0.19 / NC4:0.26 / IC5:0.07
*
COMPRESS IN GASIN OUT S1 UID=K1 DESC='GAS COMPRESSOR'
CALC POUT=250 POLY EFF=78
*
HEATEXCH IN S1 OUT S2 UID=E1 DESC='GAS COOLER'
HOT OUT=S2 FEED=S1 TEMP=50 DP=0
*
PIPELINE IN S2 OUT GASOUT UID=SEALINE1 DESC='DEEP SEA CROSSING LINE'
PARA PHASE=MIX COORD=PROJ LUNIT=KM STEP(MT)=500
CALC ALG=1 HILIM=TBULK TPROF
POINT DIST(KM)=0 ELEV(MT)=5 DIAM(MT)=0.64208 ROUGH(MICR)=15 TEXT=6 +
K(W/MC)=59,0.3 THICK(MM)=22.23,4.2
POINT DIST=0.2 ELEV=2
POINT DIST=2.0 ELEV=3
POINT DIST=7.5 ELEV=1 TEXT=5 K=59,0.3,1.7 THICK=18.76,4.2,50
POINT DIST=9.1 ELEV=-50 TEXT=7
POINT DIST=14 ELEV=-100
POINT DIST=17 ELEV=-300 TEXT=9
POINT DIST=26.8 ELEV=-560 K=59,0.3,1.7 THICK=23.62,4.2,50
POINT DIST=39.5 ELEV=-1000 K=59,0.3,1.7 THICK=28.43,4.2,50
POINT DIST=125.0 ELEV=-1500 K=59,0.3,1.7 THICK=34.46,4.2,50
POINT DIST=210.0 ELEV=-2000
POINT DIST=223.0 ELEV=-2000
POINT DIST=527 ELEV=-2100
POINT DIST=688.0 ELEV=-2178
POINT DIST=755.0 ELEV=-2000 K=59,0.3,1.7 THICK=34.46,4.2,50
POINT DIST=820 ELEV=-1500 K=59,0.3,1.7 THICK=28.43,4.2,50
POINT DIST=885 ELEV=-1000 K=59,0.3,1.7 THICK=23.62,4.2,50
POINT DIST=920 ELEV=-560 K=59,0.3,1.7 THICK=18.76,4.2,50
POINT DIST=940.0 ELEV=-300 TEXT=7
POINT DIST=954.1 ELEV=-100 TEXT=5
POINT DIST=1035 ELEV=-50
POINT DIST=1056.1 ELEV=-32
POINT DIST=1100.0 ELEV=-20
POINT DIST=1110.0 ELEV=0
PRINT PROP
*
Output Data
PRINT HCOMB
*
*
END