Engineering, Environment

 

Simulation analysis of natural gas transmission lines using Promax

 

Nnamdi Emmanuel EZENDIOKWERE *, Victor Joseph AIMIKHE and Boma KINOGOMA



Petroleum and Gas Engineering Department, University of Port Harcourt, Port Harcourt, Nigeria

Email(s): ezendiokwerennamdi@gmail.com, victor.aimikhe@uniport.edu.ng, boma.kinigoma@uniport.edu.ng

 

*Corresponding author, phone: +2347032747175

 

 

Received: April 26, 2018 / Accepted: December 25, 2018 / Published: December 30, 2018

 

Abstract

In this study, natural gas transmission lines were simulated using Bryan Research and Engineering (BRE) ProMax 2.0 chemical process simulating software. A natural gas composition of methane composition of 90%, was modelled, for which, pipeline length, throughput, suction pressure, line diameter and line temperature were varied. Pipeline lengths of 50,100, 200 miles, throughputs of 200, 250, and 300 MMscfd, suction pressures from 500-10000 psia, line diameters of 20 and 30 inches and gas temperatures of 68- 104⁰F were used. After the simulations, special emphasis was laid on the relationship between total compressor power requirements and pipeline parameters like pipeline pressure drop, length, throughput, and compression station suction pressure in order to evaluate their effects on total compressor horsepower. From more than 1000 data points recorded, it was deduced that there exists, generally, positive correlation between total compressor power and the other pipeline parameters considered. Also, there was a critical pressure drop for each combination of throughput, length and line diameter of a pipeline below which total compressor power significantly varies with pressure drop and above which total compressor power does not change considerably.

Keywords

Pipelines; Compressors; Pressure drop; Promax; Throughput

 

Introduction

 

The reliable transportation of processed natural gas from producing areas to where they are needed involves the use of a specialized system of transportation. This is because the natural gas that consumers receive, sometimes, travel long distances before getting to customers. Basically, the transportation system for natural gas consists of specialized network of interconnected pipes, dedicated to bringing natural gas to the doorsteps of gas users [1].

Pipelines in gas transport systems can be grouped into three: gathering, transmission and distribution systems. The gathering lines consists of low pressure, small diameter pipes that carry unprocessed natural gas from well heads to gas processing plants. After processing the gas, natural gas then goes to the transmission system. In gas transmissions lines, gas is carried in high pressure larger diameter pipes over long distances to where the customers reside. While distribution systems consist of another set of low-pressure, small-diameter pipelines whose task is to ultimately take gas to end users like households, factories and power plants [1].

Natural gas transportation requires a lot of energy, usually in the form of pressure energy. And a lot of this energy is spent running compressors in compression stations. Normally, the operating cost of running the compressor stations represents between 25% and 50% of a pipeline company’s operating budget [2].

Therefore, the purpose of this study is to undertake a simulation analysis of gas transmission lines, particularly their total compressor power requirements. This is because the ability to fully understand pipeline parameters and their effects on the total compressor power requirements of gas transmission lines will help in reducing compressor power burdens of natural gas transmission lines. Ultimately, research outcomes developed here will become useful insights, especially, in the hands of pipeline design engineers.

 

Material and method

 

A simplified working algorithm used for the simulations done in this study using a flow chart (Figure 1). The following procedure was used for the ProMax simulations:

(a)    Open the ProMax simulation software by either double clicking on BRE ProMax shortcut on desktop or the ProMax icon initially pinned to taskbar.

(b)   The ProMax software will open revealing a small dialogue window at the center of the screen.

(c)    Click on the blank project radio button to start a new project, causing a blank flow sheet to open simultaneously opening a shapes window on the left side of the screen.

(d)   Since a gas transmission line is being simulated, click and drag the following blocks from the shapes window to the center of the blank flowsheet.

·         a compressor from fluid drivers group of blocks.

·         a heat exchanger (after cooler) from heat exchangers.

·         a pipe section from miscellaneous.

·         a two-phase vertical separator from separators.

(e)    In the case of 100 and 200 miles pipeline sections, also click and drag a cross flowsheet connector to flowsheet. The blocks will turn red until they are properly connected.

(f)    Assign an environment to the flowsheet by clicking on the environment icon in ProMax menu, choose the Soave Redlich Kwong (SRK) property package and install the following components: Nitrogen, carbon (iv) oxide, methane, ethane, propane, iso-butane, butane, iso-pentane, pentane, and hexane.

(g)   Click on the pointer icon in ProMax tools bar to change the cursor to connector mode.

(h)   Connect the process streams first by connecting appropriate process stream connection point on each block.

(i)     Next click on the energy streams icon at the bottom of the shapes window to change the cursor to energy stream connection mode.

(j)     Connect the appropriate energy streams from the compressor to the gas pipeline.

(k)   If the connections are right, the blocks will change from red to blue.

(l)     Double click on each on each stream and block to set the relevant specifications. The streams and blocks will all turn green if the right number of correct specifications are made.

(m)  Run the simulation by clicking on the solve button with a capital letter p on top of an inverted chevron character in the project viewer window.

(n)   Warnings displayed in different colors in a small window under the flowsheet in the main window should serve as hints in cases of unsuccessful simulations.

(o)   To generate a report at the end of a successful simulation, click on the report icon on the ProMax menu in the main window, and choose items to include in the report after indicating the report file format.

Figure 1. ProMax simulation flow chart

 

Figure 2 shows a schematic diagram of a simple 50-mile gas transmission line model used for the simulation.

Figure 2. Schematic diagram of a simple gas transmission line model

 

The procedure represented above was used to simulate 50-mile, 100-mile and 200-mile long natural gas transmission lines. Using the different combinations of pipeline length, pipeline diameter, gas flow rate, and compositions, over a thousand simulations were done. In other to ensure that the simulated gas transmission lines were as close to their real life counterparts as possible, the whole length of the lines was divided into 50 mile sections by compression stations, with each section containing at least three (3) valve stations. The valve stations were positioned after every 20 miles, except when the valve station occurs very close to a compression station.

Table 1 shows the natural gas composition used for the simulation.

 

Table 1. Composition of natural gas used for simulation

Composition

Mole percent

(%)

C1

90.0

C2

4.20

C3

2.68

i-C4

1.08

n-C4

0.17

i-C5

0.02

n-C5

0.01

n-C6

0.02

CO2

0.55

N2

1.27

A processed sweet natural gas with composition similar to TransCanada transmission line gas was used. The processed sweet natural gas has a methane composition of 90%. But, the sweet gas composition had carbon (iv) oxide and nitrogen compositions of 0.55 and 1.27 mole percent respectively.

Also, to maintain accuracy of the simulation, different flow sheets were used for each 50-mile gas transmission line section. The different flow sheets were then joined using Promax cross-flow sheet connector to ensure proper exchange of both process and energy streams between flow sheets. For the choice of equation of state, the Soave Redlich Kwong (SRK) equation of state was used. Although, Peng Robinson could have been used, but SRK gives better results when compared with Peng Robinson for natural gas applications.

Begs and Brill multiphase correlation was used because of its wide acceptance in the oil and gas industry. For the pipe, a buried standard steel pipe of overall heat transfer coefficient of 0.25 W/m2-oK was used. This allows some heat to escape through the pipe wall into the surrounding. An after cooler was also added after each compressor to ensure that the temperature of the sweet gas after compression does not exceed 1000F. A polytropic efficiency of 80% and a compression ratio of 2 was chosen to avoid unnecessarily overheating of the gas in transit. This was done because compressor stations at gas transmission lines normally have compression ratios of 2 [3].

Considering the effect of flow rate on gas transportation in general, three (3) different flow rates were considered while simulating the gas transmission lines, they include: 200,250, and 300 MMSCFD. Due to the fact that Promax gives accurate results only for pipeline simulations with pressure drop less than 10%, any simulation result with pressure drop above 10% of the pipeline inlet pressure in any pipe section was discarded. This was done to preserve the integrity of the generated Promax data. Steps between data points were deliberately made small in other to preserve accuracy.

 

Results and discussion

 

Figure 3 shows an example of the graphical plot of compressor power requirement against total line pressure drop for different combinations of transmission pipeline length, line diameter, and gas flow rate. Plots for other pipe lengths were predominantly of this shape.

Figure 3. Graph of compressor power requirements against pressure drop for 100 mi, 20”, 200MMSCFD, 68⁰F

 

From the graphs by Figure 3, generally, as total line pressure drop increases, total compressor requirements decreases. But, a closer look at the graphs as represented by Figure 3 will reveal three prominent behaviors between compressor requirement and the accompanying pressure loss. For the first part of the plot (low pressure drop range), corresponding to very high line pressures, small changes in total line pressure drop lead to significantly large changes in compressor power.

After that almost linear relationship, each curve then experiences a change in direction, before finally levelling out. For this last part of each curve, corresponding to lower pipeline pressures, the compressor power does not significantly change, even as total line pressure drop increases. This behavior can be attributed to the fact that at higher pipeline pressures, slight changes in conditions normally create big pressure waves that are easily transmitted throughout the whole pipeline system. But, changes at low pressures are hardly felt, since pipeline transportation is primarily facilitated by changes in pressure energy.

 

Table 2. Summary of results from ProMax simulations

Pipeline Length (mi)

Gas flow rate

(MMscfd)

Pipeline

Diameter (in)

Critical pressure

drop (psia)

Compressor

Power (hp)

50

200

20

55.3552

8235.77

30

6.39278

8235.77

250

20

86.9493

9183.53

30

9.97234

9183.53

 

300

20

107.282

12434.2

30

12.3460

12434.2

100

200

20

103.5659

26962.96

30

11.97024

26847.32

250

20

170.3547

32813.45

30

21.46403

32845.85

300

20

278.5072

39301.3

30

30.91819

39600.8

200

200

20

205.9134

36206.43

30

22.75965

37276.36

250

20

313.6289

45767.02

30

35.23813

46773.51

 

From the aforementioned simulations, a summary of the relationship among various parameters was obtained, as captured in Table 2 above. Specifically, total compressor power increases as the pipeline length increases, as can be seen from Table 2.

Also, in Table 2, it can be deduced that the total compressor power increases as throughput increases. Hence, from the table, it can be deduced that the relationship between total compressor power requirement and the pipeline parameters considered can be generally described as positive correlation.

Especially, there was positive correlation between total compressor power and critical pressure drop. Where the critical pressure drop is taken as the total line pressure drop value corresponding to the point on the total compressor power-total pressure drop graph at which the curve begins to flatten out. And this general trend between total compressor requirements and other pipeline parameters is basically true. This is because, increased flow rate means more gas is being transported, and the larger the quantity of gas, the longer the lines, the bigger the diameter and the bigger the compression power that will naturally be needed. Ultimately, leading to higher pressure drop due friction in the pipelines.

Figure 4. A plot showing the relationship between compressor power and suction pressure

 

The relationship between suction pressures and compressor power was shown graphically in Figure 4 above. While, for suction pressures, the compressor power generally, increases as line pressure increases. But, a closer look will reveal that there was an initial dip or decrease in compressor power requirement as suction pressure increased. And then, continuous increase in compressor power as suction pressure increased. The dip in the curve can be attributed to the effect of the value of compressibility factor (z). This is because, as pressure increases, z-factor first decreases in value until it reaches a minimum, before it starts increasing as the pressure increases [3].

 

Conclusion

 

From the study, the following conclusions can be drawn:

(a)    Gas transmission line total compressor power requirement increases as the transmission line length increases.

(b)   Gas transmission line total compressor power requirement increases as the transmission line throughput increases.

(c)    Gas transmission line total compressor power requirement increases as the transmission compressor station suction pressures increases.

(d)   There was a critical pressure drop for each combination of throughput, length and line diameter of a pipeline below which compressor power significantly varies with pressure drop and above which compressor power does not change considerably.

 

References

 

1. Rios M. and Borraz S., Optimization problems in natural gas transportation systems: A state-of-the-art review, Applied Energy, 147, p. 536-555.

2. Luongo C.A., Gilmour B.J., and Schroeder D.W., Optimization in natural gas transmission networks: A tool to improve operational efficiency, Technical report, Stoner Associates, Inc., Houston, 1989.

3. Chi U.I, Natural gas production engineering, John Wiley & Sons, Inc., 1992.

4. Agwu O.E., Markson I.E., Umana M.O., Minimizing energy consumption in compression stations along two gas pipelines in Nigeria, American Journal of Mechanical Engineering and Automation, 2016, 3 (4), p. 29-34.

5. Agwu O., Eleghasim C., Mechanical drive gas turbine selection for service in two natural gas pipelines in Nigeria, Case Studies in Thermal Engineering, 2017, 10, p. 19-27.

6. Aimikhe V., Kinigoma B. and Iyagba E., Predicting the produced boil off gas in the moss spherical liquefied natural gas (LNG) Vessel, SPE Nigeria Annual International Conference and Exhibition, 2013.

7. Amyx J.W., Bass D.M. Jr., and Whiting R.L., Petroleum reservoir engineering-physical properties, New York: McGraw-Hill, 1960.

8. Armstrong J.S., Illusions in regression analysis, International Journal of Forecasting, 2012, 28 (3), 689.

9. Campbell J.M., Gas conditioning and processing, Norman, Oklahoma, Campbell Petroleum Series, 1976.

10. Comodi G., Renzi M., Caresana F., Pelagalli L., Enhancing micro gas turbine performance in hot climates through inlet air cooling vapor compression technique, Appl. Energy, 2015, 147, p. 40-48.

11. David A.F., Statistical models: Theory and practice, Cambridge University Press, 2005.

12. McCain W.D., Jr., The properties of petroleum fluids, Tulsa: Petroleum Publishing, 1973.

13. Mohammad M.G. and Alireza B., A new correlation for accurate estimation of natural gases water content, Journal of Petroleum and coal, 2014.

14. Moshfeghian M., Dense transportation of natural gas, Campbell January Tip of the Month, 2010.

15. Musaab M.A. and Mohammed A.A., A comprehensive study on the current pressure drop calculation in multiphase vertical wells, Current Trends and Future Perspectives, Journal of Applied Sciences, 2014, 14, p. 3162-3171.

16. Sa A.D., Al Zubaidy S., Gas turbine performance at varying ambient temperatures, Appl. Thermo Eng., 2011, 31, p. 2735-2739.

 

Appendix

 

Table A1. Promax results for a 100 mi, 20 and 30 in pipelines with gas flowrate of 200 MMScfd

100mi

20"

200MMSCFD

68⁰F

P(Feed)(psia)

Comp1(hp)

Comp2(hp)

P2(Psia)

T2 (˚F)

∆P1(Psia)

∆P2(psia)

∑∆P(psia)

∑Comp(hp)

500

8004.85

17535.4

3117.53

73.3753

200.456

55.6459

256.1019

25540.25

550

7953.78

17567.3

3621.18

73.4149

175.927

50.1091

226.0361

25521.08

600

7904.42

17620.3

4101.08

73.3388

156.888

46.3658

203.2538

25524.72

650

7856.82

17692

4564.81

73.2231

141.638

43.6416

185.2796

25548.82

700

7811.12

17781.2

5016.88

73.0983

129.142

41.5539

170.6959

25592.32

750

7767.21

17886.8

5460.19

72.8607

118.728

39.8927

158.6207

25654.01

800

7725.2

18008.5

5896.74

72.7537

109.933

38.5323

148.4653

25733.7

850

7685.13

18245.7

6327.91

72.6552

102.424

37.393

139.817

25930.83

900

7647.06

18298.2

6754.75

72.5646

95.9566

36.4218

132.3784

25945.26

950

7611.03

18465.3

7178.04

72.4814

90.3442

35.5815

125.9257

26076.33

1000

7577.08

18646.6

7598.39

72.2081

85.442

34.8457

120.2877

26223.68

1200

7463.02

19499.9

9258.59

72.0046

70.9477

32.6182

103.5659

26962.92

1400

7385.67

20250.2

10897.2

71.8475

61.6704

31.0965

92.7669

27635.87

1600

7346.83

21658.6

12533.6

71.7224

55.3552

29.9786

85.3338

29005.43

1800

7347.13

22576.5

14142.6

71.6203

50.8287

29.1168

79.9455

29923.63

2000

7385

24146.8

15756.8

71.5355

47.4415

28.429

75.8705

31531.8

2200

7457.25

25451.1

17367.9

71.4637

44.8153

27.8658

72.6811

32908.35

2400

7559.34

26777.3

18976.7

71.4022

42.77189

27.3952

70.16709

34336.64

2600

7687.13

28227.9

20584

71.3489

41.0048

26.9956

68.0004

35915.03

2800

7835.52

29467.4

22190

71.3023

39.5752

26.6515

66.2267

37302.92

3000

8000.71

30822.2

23795.2

71.2611

38.363

26.3522

64.7152

38822.91

3200

8179.34

32179.9

25399.6

71.2244

37.3207

26.0891

63.4098

40359.24

3400

8368.68

33579

27003.5

71.1916

36.4137

25.856

62.2697

41947.68

3600

8566.66

34898.1

28606.9

71.1621

35.6163

25.6479

61.2642

43464.76

3800

8771.37

36256.5

30209.9

71.1353

34.9092

25.461

60.3702

45027.87

4000

8981.52

36613.7

31812.6

71.111

34.2771

25.2922

59.5693

45595.22

4200

9196

38969.2

33415

71.0887

33.7083

25.1389

58.8472

48165.2

4400

9413.97

40322.9

35017.2

71.0683

33.1934

24.9991

58.1925

49736.87

4600

9634.71

41674.6

36619.2

71.0495

32.7246

24.8711

57.5957

51309.31

4800

9857.69

43024.3

38221.1

71.0321

32.296

24.7534

57.0494

52881.99

5000

10082.5

44371.4

39822.7

71.016

31.9022

24.6448

56.547

54453.9

5200

10308.6

45716.5

41424.3

71.0011

31.5391

24.4553

55.9944

56025.1

5400

10536

45059.4

43025.7

71.9871

31.203

24.451

55.654

55595.4

5600

10764.2

48400.2

44627.1

70.9871

30.891

24.3643

55.2553

59164.4

5800

10993.1

49738.8

46228.3

70.9741

30.6

24.2833

54.8833

60731.9

6000

11222.6

51075.3

47829.5

70.9619

30.329

24.2075

54.5365

62297.9

6200

11452.4

52409.7

49430.6

70.9505

30.0749

24.1366

54.2115

63862.1

6400

11682.6

53742.2

51031.6

70.9398

29.8365

24.0699

53.9064

65424.8

6600

11912.9

55072.7

52632.5

70.9297

29.6123

24.0072

53.6195

66985.6

6800

12143.4

56401.2

54233.4

70.9201

29.4009

23.9481

53.349

68544.6

7000

12373.9

57728.1

53834.3

70.9111

29.2014

23.8924

53.0938

70102

7200

12604.5

59033.1

57435.1

70.9026

29.0127

23.8395

52.8522

71637.6

7400

12835

60376.4

59035.9

70.8945

28.8339

23.7895

52.6234

73211.4

7600

13065.3

61698

60636.6

70.8868

28.6642

23.7421

52.4063

74763.3

7800

13295.6

63098

62237.3

70.8795

28.5029

23.0697

51.5726

76393.6

8000

13525.8

64336.5

63958.3

65.3139

28.3495

23.6542

52.0037

77862.3

8200

13755.9

65653.5

65558.3

65.3087

28.2032

23.6134

51.8166

79409.4

8400

13985.8

66969

67158.4

65.3037

28.0637

23.5745

51.6382

80954.8

8600

14215.4

68283.1

68758.5

65.2989

27.9305

23.5374

51.4679

82498.5

8800

14444.9

69595.8

70358.5

65.2944

27.803

23.502

51.305

84040.7

9000

14674.2

70907.2

71958.5

65.29

27.6811

23.502

51.1831

85581.4

9200

14903.3

72217.4

73558.6

65.2859

27.5642

23.4681

51.0323

87120.7

9400

15132.1

73526.3

75158.6

65.2819

27.452

23.4045

50.8565

88658.4

9600

15360.7

74834

76758.7

65.278

27.3444

23.3747

50.7191

90194.7

9800

15589.1

76140.6

78358.7

65.27443

27.241

23.3461

50.5871

91729.7

10000

15817.2

77446

79958.8

65.2708

27.1415

23.3186

50.4601

93263.2

30"

500

8004.85

17534.9

3885.96

67.7792

20.8581

5.61079

26.46889

25539.75

550

7953.78

17559.1

4294.9

67.626

18.7005

5.29775

23.99825

25512.88

600

7904.42

17600.7

4702.23

67.4767

16.9299

5.05164

21.98154

25505.12

650

7856.82

17660.3

5108.32

67.3371

15.4563

4.85279

20.30909

25517.12

700

7811.12

17737.2

5513.45

67.2091

14.2143

4.68854

18.90284

25548.32

750

7767.21

17831

5917.82

67.0928

13.1571

4.55038

17.70748

25598.21

800

7725.2

17941.8

6321.57

66.9873

12.2497

4.43238

16.68208

25667

850

7685.13

18069.2

6724.81

66.8916

11.4653

4.33029

15.79559

25754.33

900

7647.06

18212.9

7127.63

66.8046

10.7831

4.24099

15.02409

25859.96

950

7611.03

18372.5

7530.09

66.7254

10.1864

4.16217

14.34857

25983.53

1000

7577.08

18547.5

7932.26

66.6531

9.66201

4.092

13.75401

26124.58

1200

7463.02

19384.3

9538.74

66.418

8.09635

3.87389

11.97024

26847.32

1400

7385.67

20398.5

11142.9

66.2446

7.08454

3.72101

10.80555

27784.17

1600

7346.83

21535.2

12745.8

66.1117

6.39278

3.60733

10.00011

28882.03

1800

7347.13

22753.4

14347.9

66.0235

5.89596

3.47568

9.37164

30100.53

2000

7385

24024.5

15949.5

65.9213

5.5239

3.44878

8.97268

31409.5

2200

7457.25

25329.9

17550.7

65.8507

5.23541

3.39112

8.62653

32787.15

2400

7559.34

26657.2

19151.6

65.7913

5.00522

3.34301

8.34823

34216.54

2600

7687.13

27998.6

20752.4

65.7406

4.81716

3.30223

8.11939

35685.73

2800

7835.52

29348.8

22353.1

65.6968

4.66049

3.26721

7.9277

37184.32

3000

8000.71

30704.1

23953.7

65.6586

4.52781

3.23681

7.76462

38704.81

3200

8179.34

32062.3

25554.1

65.6249

4.41388

3.21017

7.62405

40241.64

3400

8368.68

33421.6

27154.6

65.595

4.31489

3.18662

7.50151

41790.28

3600

8566.66

34781

28754.9

65.5683

4.22799

3.16566

7.39365

43347.66

3800

8771.37

36139.6

30355.2

65.5443

4.15106

3.14689

7.29795

44910.97

4000

8981.52

37496.9

31955.5

65.5226

4.0824

3.12997

7.21237

46478.42

4200

9196

38852.5

33555.8

65.5029

4.02073

3.11465

7.13538

48048.5

4400

9413.97

40206.2

35156

65.4849

3.96498

3.10071

7.06569

49620.17

4600

9634.71

41557.9

36756.3

65.4684

3.91433

3.08798

7.00231

51192.61

4800

9857.69

42907.4

38356.5

65.4533

3.86806

3.07631

6.94437

52765.09

5000

10082.5

44254.7

39956.8

65.4393

3.82566

3.06556

6.89122

54337.2

5200

10308.6

45599.7

41556.8

65.4264

3.78662

3.05564

6.84226

55908.3

5400

10536

46942.6

43157

65.4144

3.75054

3.04645

6.79699

57478.6

5600

10764.2

48283.2

44757.1

65.4032

3.7171

3.03791

6.75501

59047.4

5800

10993.1

49621.7

46357.2

65.3927

3.68601

3.02997

6.71598

60614.8

6000

11222.6

50958

47957.3

65.383

3.65701

3.02255

6.67956

62180.6

6200

11452.4

52292.4

49557.5

65.3738

3.62991

3.01562

6.64553

63744.8

6400

11682.6

53624.7

51157.6

65.3653

3.60452

3.00911

6.61363

65307.3

6600

11912.9

54955.1

52757.7

65.3572

3.58067

3.00301

6.58368

66868

6800

12143.4

56284.8

54357.9

65.3495

3.52055

2.99726

6.51781

68428.2

7000

12373.9

57611.2

55958

65.3423

3.49635

2.99185

6.4882

69985.1

7200

12604.5

58935.8

57558.1

65.3376

3.47321

2.98674

6.45995

71540.3

7400

12835

60258.7

59158.2

65.3313

3.45106

2.98191

6.43297

73093.7

7600

13065.3

61580

60758.3

65.3252

3.4298

2.97733

6.40713

74645.3

7800

13295.6

62899.6

62358.2

65.3194

3.46328

2.97299

6.43627

76195.2

8000

13525.8

64218

63958.2

65.3139

3.44712

2.96888

6.416

77743.8

8200

13755.9

65534.8

65558.3

65.3087

3.43175

2.96496

6.39671

79290.7

8400

13985.8

66850.2

67158.4

65.3037

3.4171

2.96123

6.37833

80836

8600

14215.4

68164.2

68758.4

65.2989

3.40313

2.95768

6.36081

82379.6

8800

14444.9

69476.8

70358.5

65.2944

3.38979

2.95429

6.34408

83921.7

9000

14674.2

70788.1

71958.5

65.29

3.37703

2.95105

6.32808

85462.3

9200

14903.3

72098.1

73558.6

65.2859

3.36482

2.94795

6.31277

87001.4

9400

15132.1

73406.9

75158.6

65.2819

3.35312

2.94499

6.29811

88539

9600

15360.7

74714.5

76758.7

65.278

3.34191

2.94216

6.28407

90075.2

9800

15589.1

76020.9

78358.7

65.2744

3.33115

2.93944

6.27059

91610

10000

15817.2

77326.2

79958.8

65.2708

3.32081

2.93683

6.25764

93143.4

 

Figure A1. Graph of compressor power requirements against pressure drop for 100 mi, 20”, 200 MMSCFD

Figure A2. Graph of compressor power requirements against pressure drop for 100mi, 30”, 200 MMSCFD