presentation on calculation of line pack of natural gas pipe using aspen plus dynamics and using...
TRANSCRIPT
![Page 1: Presentation on Calculation of Line Pack of Natural Gas Pipe using Aspen PLUS Dynamics and using Manual Calculations](https://reader031.vdocuments.us/reader031/viewer/2022012309/587014c21a28ab7f428b523b/html5/thumbnails/1.jpg)
COMPARISON OF LINE PACK CALCULATION USING ASPEN PLUS DYNAMICS AND BY USING MANUAL
CALCULATIONSPREPARED BY:
MUHAMMAD WAQAS MANZOOR
PROCESS ENGINEER
Contact: [email protected]
![Page 2: Presentation on Calculation of Line Pack of Natural Gas Pipe using Aspen PLUS Dynamics and using Manual Calculations](https://reader031.vdocuments.us/reader031/viewer/2022012309/587014c21a28ab7f428b523b/html5/thumbnails/2.jpg)
LINE PACK
• The quantity of natural gas contained in a certain segment of a pipeline is known as line pack.
• It is typically measured in MMSCF.
![Page 3: Presentation on Calculation of Line Pack of Natural Gas Pipe using Aspen PLUS Dynamics and using Manual Calculations](https://reader031.vdocuments.us/reader031/viewer/2022012309/587014c21a28ab7f428b523b/html5/thumbnails/3.jpg)
CALCULATION USING ASPEN PLUS DYNAMICS
• First of all, build a steady statesimulation of the pipe linesegment, in Aspen PLUS
![Page 4: Presentation on Calculation of Line Pack of Natural Gas Pipe using Aspen PLUS Dynamics and using Manual Calculations](https://reader031.vdocuments.us/reader031/viewer/2022012309/587014c21a28ab7f428b523b/html5/thumbnails/4.jpg)
SPECIFICATIONS OF PIPE SEGMENT IN ASPEN PLUS
![Page 5: Presentation on Calculation of Line Pack of Natural Gas Pipe using Aspen PLUS Dynamics and using Manual Calculations](https://reader031.vdocuments.us/reader031/viewer/2022012309/587014c21a28ab7f428b523b/html5/thumbnails/5.jpg)
SPECIFICATIONS OF PIPE SEGMENT IN ASPEN PLUS
![Page 6: Presentation on Calculation of Line Pack of Natural Gas Pipe using Aspen PLUS Dynamics and using Manual Calculations](https://reader031.vdocuments.us/reader031/viewer/2022012309/587014c21a28ab7f428b523b/html5/thumbnails/6.jpg)
SPECIFICATIONS OF VALVE ‘BV-1’ IN ASPEN PLUS
![Page 7: Presentation on Calculation of Line Pack of Natural Gas Pipe using Aspen PLUS Dynamics and using Manual Calculations](https://reader031.vdocuments.us/reader031/viewer/2022012309/587014c21a28ab7f428b523b/html5/thumbnails/7.jpg)
SPECIFICATIONS OF VALVE ‘BV-1’ IN ASPEN PLUS
![Page 8: Presentation on Calculation of Line Pack of Natural Gas Pipe using Aspen PLUS Dynamics and using Manual Calculations](https://reader031.vdocuments.us/reader031/viewer/2022012309/587014c21a28ab7f428b523b/html5/thumbnails/8.jpg)
SPECIFICATIONS OF VALVE ‘BV-2’ IN ASPEN PLUS
![Page 9: Presentation on Calculation of Line Pack of Natural Gas Pipe using Aspen PLUS Dynamics and using Manual Calculations](https://reader031.vdocuments.us/reader031/viewer/2022012309/587014c21a28ab7f428b523b/html5/thumbnails/9.jpg)
SPECIFICATIONS OF VALVE ‘BV-2’ IN ASPEN PLUS
![Page 10: Presentation on Calculation of Line Pack of Natural Gas Pipe using Aspen PLUS Dynamics and using Manual Calculations](https://reader031.vdocuments.us/reader031/viewer/2022012309/587014c21a28ab7f428b523b/html5/thumbnails/10.jpg)
SPECIFICATIONS OF INLET STREAM ‘NG-1’ IN ASPEN PLUS
![Page 11: Presentation on Calculation of Line Pack of Natural Gas Pipe using Aspen PLUS Dynamics and using Manual Calculations](https://reader031.vdocuments.us/reader031/viewer/2022012309/587014c21a28ab7f428b523b/html5/thumbnails/11.jpg)
EXPORTING SIMULATION TO ASPEN PLUS DYNAMICS
• After that, set ‘Input mode’ to ‘dynamic’ from ‘steady state’.
![Page 12: Presentation on Calculation of Line Pack of Natural Gas Pipe using Aspen PLUS Dynamics and using Manual Calculations](https://reader031.vdocuments.us/reader031/viewer/2022012309/587014c21a28ab7f428b523b/html5/thumbnails/12.jpg)
EXPORTING SIMULATION TO ASPEN PLUS DYNAMICS
• After that, click on ‘File Menu’, and select ‘Pressure Driven’ from ‘Update Aspen PLUS Dynamics Menu’.
![Page 13: Presentation on Calculation of Line Pack of Natural Gas Pipe using Aspen PLUS Dynamics and using Manual Calculations](https://reader031.vdocuments.us/reader031/viewer/2022012309/587014c21a28ab7f428b523b/html5/thumbnails/13.jpg)
EXPORTING SIMULATION TO ASPEN PLUS DYNAMICS
• These 03 files and a folder are created in the same folder where Aspen PLUS ‘.bkp‘ file was previously stored.
![Page 14: Presentation on Calculation of Line Pack of Natural Gas Pipe using Aspen PLUS Dynamics and using Manual Calculations](https://reader031.vdocuments.us/reader031/viewer/2022012309/587014c21a28ab7f428b523b/html5/thumbnails/14.jpg)
SNAPSHOT OF ASPEN PLUS DYNAMICS WINDOW
![Page 15: Presentation on Calculation of Line Pack of Natural Gas Pipe using Aspen PLUS Dynamics and using Manual Calculations](https://reader031.vdocuments.us/reader031/viewer/2022012309/587014c21a28ab7f428b523b/html5/thumbnails/15.jpg)
INITIAL BOUNDARY CONDITIONS IN ASPEN PLUS DYNAMICS
![Page 16: Presentation on Calculation of Line Pack of Natural Gas Pipe using Aspen PLUS Dynamics and using Manual Calculations](https://reader031.vdocuments.us/reader031/viewer/2022012309/587014c21a28ab7f428b523b/html5/thumbnails/16.jpg)
FINAL BOUNDARY CONDITIONS IN ASPEN PLUS DYNAMICS
![Page 17: Presentation on Calculation of Line Pack of Natural Gas Pipe using Aspen PLUS Dynamics and using Manual Calculations](https://reader031.vdocuments.us/reader031/viewer/2022012309/587014c21a28ab7f428b523b/html5/thumbnails/17.jpg)
CONFIGURATION OF PIPE SEGMENT IN ASPEN PLUS DYNAMICS
![Page 18: Presentation on Calculation of Line Pack of Natural Gas Pipe using Aspen PLUS Dynamics and using Manual Calculations](https://reader031.vdocuments.us/reader031/viewer/2022012309/587014c21a28ab7f428b523b/html5/thumbnails/18.jpg)
CALCULATION USING ASPEN PLUS DYNAMICS
![Page 19: Presentation on Calculation of Line Pack of Natural Gas Pipe using Aspen PLUS Dynamics and using Manual Calculations](https://reader031.vdocuments.us/reader031/viewer/2022012309/587014c21a28ab7f428b523b/html5/thumbnails/19.jpg)
CALCULATION OF LINE PACK FROM SIMULATION RESULTS OF ASPEN PLUS DYNAMICS• Molar concentration of gas within the pipe segment = 0.160589 lbmol/cf
• Actual volume of pipe segment = 3.14 x {(14.314/12)^2} /4 x 528000 ft = 590042.558 cf
• Number of Moles of gas contained in the pipe segment = 0.160589 lbmol/cf x 590042.558 cf = 94754.344 lbmol
Calculation of Molar Volume at Standard Conditions:• Molar Volume (Vmn) of any gas at normal conditions i.e. 0 C & 1 atm, is given by,
• Vmn = 22.414 Nm3 / kgmole = 22.414 Nm3 x (1 ft /0.3048 m)^3 x 0.454 kgmol/lbmol
• Vmn = 359.360 Ncf/lbmol
• Molar volume (Vms) at standard conditions i.e. 60 F (15.55 C) and 14.7 psia (1 atm), is given by
• 359.360 cf x 14.7 psi / 492 F = Vms x 14.7 / 520 F
• Or, Vms = 379.811 Scf/lbmol
Calculated Line Pack = 94754.344 lbmol x 379.811 Scf/lbmol = 35.988 MMSCF
![Page 20: Presentation on Calculation of Line Pack of Natural Gas Pipe using Aspen PLUS Dynamics and using Manual Calculations](https://reader031.vdocuments.us/reader031/viewer/2022012309/587014c21a28ab7f428b523b/html5/thumbnails/20.jpg)
EQUATIONS USED FOR MANUAL CALCULATION OF LINE PACK
• Here Vb represents Line Pack,calculated for a pipe segmenthaving an internal diameter D,length L, and containing naturalgas at an average pressure andtemperature of Pavg, and Tavg,respectively.
• Tb, and Pb represent thr basetemperature and base pressure,respectively.
Ref: ‘Gas Pipeline Hydraulics’ by E. Shashi Menon
![Page 21: Presentation on Calculation of Line Pack of Natural Gas Pipe using Aspen PLUS Dynamics and using Manual Calculations](https://reader031.vdocuments.us/reader031/viewer/2022012309/587014c21a28ab7f428b523b/html5/thumbnails/21.jpg)
CALCULATION OF COMPRESSIBILITY FACTOR
Ref: ‘Gas Pipeline Hydraulics’ by E. Shashi Menon
![Page 22: Presentation on Calculation of Line Pack of Natural Gas Pipe using Aspen PLUS Dynamics and using Manual Calculations](https://reader031.vdocuments.us/reader031/viewer/2022012309/587014c21a28ab7f428b523b/html5/thumbnails/22.jpg)
CALCULATION OF AVERAGE PRESSURE AND AVERAGE TEMPERATURE
• Here P1 and P2 are in absolutepressure units.
• Average Temperature istypically calculated by takingarithmetic mean of inlet andout temperatures (in absoluteunits) of the pipe segment.
Ref: ‘Gas Pipeline Hydraulics’ by E. Shashi Menon
![Page 23: Presentation on Calculation of Line Pack of Natural Gas Pipe using Aspen PLUS Dynamics and using Manual Calculations](https://reader031.vdocuments.us/reader031/viewer/2022012309/587014c21a28ab7f428b523b/html5/thumbnails/23.jpg)
MANUAL CALCULATION OF LINE PACK• Molecular Mass of gas used in Aspen PLUS simulation = 16.0427 lb/lbmol
• Specific gravity of gas = 16.0427 / 29 = 0.5531
• Pressure of gas at Inlet of pipe segment = 898.093 psia
• Pressure of gas at Outlet of pipe segment = 702.895 psia
• Average Pressure of gas across the pipe segment = 898.093 + 702.895 − . × .. .
= 804.460 psia = 789.76 psig (1 atm = 14.7 psia)
• Temperature of gas at Inlet of pipe segment = 74.1135 F = 534.1135 R
• Temperature of gas at Outlet of pipe segment = 63.44 F = 523.44 R
• Average Temperature of gas across the pipe segment = . . = 528.776 R
• Average compressibility of gas across the pipe segment = . × × . × .
. .
= 0.90807
![Page 24: Presentation on Calculation of Line Pack of Natural Gas Pipe using Aspen PLUS Dynamics and using Manual Calculations](https://reader031.vdocuments.us/reader031/viewer/2022012309/587014c21a28ab7f428b523b/html5/thumbnails/24.jpg)
MANUAL CALCULATION OF LINE PACK• Base Temperature = 60 F = 520 R
• Base Pressure = 14.7 psia
• Internal Diameter of pipe segment = 14.314 inches
• Total Length of pipe segment = 100 miles = 528000 ft
• Line Pack (Vb) calculated using CNGA* method is given by,
• Vb = 28.798 × .
× . . × .
× 14.314 × 100푚푖푙푒푠
• Vb = 34.969 MMSCF
• Line pack calculated using Aspen PLUS Dynamics = 35.988 MMSCF
• The calculated Line Pack ‘Vb’ closely matches with the line pack calculated using Aspen PLUS Dynamics.
• The difference between the two, may be attributed to the difference in physical properties calculationmethods and computational methods in Aspen PLUS Dynamics. However, results of Aspen PLUS Dynamicsare more accurate.
* California Natural Gas Association