wrong sizing of a reciprocating compressor

Rev 3

PRESENTATION

FORWARDED TO:

WORLD CORPORATIONS IN:

• Chemical and gas processing

• Gas Transportation

• Refining

• Oil and gas field operation, and

• Engineering projects and consulting.

Caracas, March 2014

WRONG SIZING

OF A RECIP COMPRESSOR IN OIL AND GAS SERVICE

Presented at

2014 Windrock Conference Stone Mountain Park

GA, USA

Wrong Sizing of a Recip Compressor Rev 3 March14

CONTENT

CONTENT

1.- INTRODUCTION ............................................................................................................... 4

2.- EXISTING COMPRESOR CONFIGURATION ................................................................. 7

4.- BASIC DATA TO ESTIMATE NUMBER OF STAGES .................................................. 11

5.- NUMBER OF STAGES AND DISCHARGE TEMPERATURE ...................................... 14

6.- BASIC PERFORMANCE MAPS ANALYSIS – POWER AND FLOW ........................... 15

Existing Case 1 ........................................................................................................... 15

Existing Case 2 ........................................................................................................... 17

Remedial Case ............................................................................................................ 18

Revamp Case .............................................................................................................. 18

Case Summary ............................................................................................................ 19

Tlf: +58.212.816.5779 Caracas, Venezuela www.turbodina.com

Móvil: +58.414.247.1337 Orlando, Florida [email protected]

2/63


CONTENT

7.- SPECIAL PURPOSE PERFORMANCE MAPS ANALYSIS .......................................... 21

Existing Case 1 ........................................................................................................... 21

Existing Case 2 ........................................................................................................... 21

Remedial Case ............................................................................................................ 23

Revamp Case .............................................................................................................. 26

ATTACHMENTS 1 TO 4 – BASIC PERFORMANCE MAPS .............................................. 30

ATTACHMENTS 5 TO 8 – SPECIAL PURPOSE PERFORMANCE MAPS ....................... 41



3/63


INTRODUCTION

1.- INTRODUCTION

What happens when a wrongly sized multistage compressor is applied in a gas

field?.

Here we present a history case for a two stage compressor in a natural gas

compresion process needding only one stage.

There are two objectives for this presentation: 1.- to see the effect of wrong

cylinder sizes and 2.- to present novel graphical tools for the diagnostic and

optimization of reciprocating compressors, as described below.

Process and compressor data is shown in Fig. 0 and Table 3.

4 / 63


INTRODUCTION

No cross–checks with field data is provided in this work for space limitations.

For convenience, the numerous figures were located at the end of this document

in separate attachments.

For the diagnostic and optimization process, we make use of the Basic

Performance Maps in Attachments 1 through 4, featuring the following

parameters:

• Absorved Power per cylinder

• Available power per cylinder

• Flow, and

• Variable volume Pocket settings

5 / 63


INTRODUCTION

Complementary Special Purpose Performance Maps as contained in

Attachments 5 through 8, are used to graphicaly depict limits for key mechanical

and thermodynamic parameters as:

• Low volumetric efficiency,

• Rod Overload,

• Rod load reversal, and

• High Discharge temperature.

6 / 63


2.- EXISTING COMPRESOR CONFIGURATION

RPM: 300

Stroke: 19”

Rod Diameter: 4”

Maximum rated power: 594 HP/cyl

Gas Handled: Natural Gas

6% fluctuation

Φ 8”

HE Variable Volume Pocket ϕ 7.75 x 16”

Cyl 1

Stage 1

Cyl 2

Stage 2

250 # 800 #

ϕ11.5 “

Fig. 0

370 #

20% fluctuation

7 / 63


BACKGROUND AND ANALYSIS CASES

3.- BACKGROUND AND ANALYSIS CASES

Operator wanted to handle maximum throughput with good reliability, but the

compressor was out of thermodynamic balance (see Attachment 1 Fig. 2)

creating also unbalance and detonations in the engine side. There was a

compressor crankshaft failure in the past. Cylinder 2 rod load reversal was a

problem as shown in Attachment 5 Figure 10, and discharge temperature a

concern at low suction pressures according to Fig. 11.

Four (4) analysis cases were prescribed in order to find a remedial approach to

mitigate the reliability problems while a revamp with the full solution was pursued

in the mid term. See Tables 1 and 2.

8 / 63



Table 1.- Analysis Cases Definitions

CASE FEATURES PURPOSE FIGS.

Existing 1 First stage variable volume

pocket fully closed

Check full power absorved and

profile. Check full flow.

Fig. 1 & 2

Attach. 1

Existing 2

First stage variable volume

pocket adjusted to match

available power

Check power absorved and

profile. Check flow.

Fig. 3 & 4

Attach. 2

Remedial

First stage variable volume

pocket fully open plus a 75%

clearance cylinder 1 crank end

bottle

An attempt to evenly distribute

the load between the two

cylinders. Check flow.

Fig. 5

Attach. 3

Revamp

Replace cylinders with bigger

ones featuring variable volume

pockets in each cylinder

Ultimate solution for maximum

flow and reliability.

Figs. 6 & 7

Attach. 4

9 / 63



Table 2.- Analysis Cases Configuration

EXISTING CASES REMEDIAL CASE REVAMP CASE

Diam (inch) Diam (inch)

C1

HE

See Fig. 0

13.5

CE Add Clearance 75 %

Var. Vol. Pocket Fully Open 11 x 16

C2

HE

See Fig.0 See Fig. 0 10.5

CE

Var. Vol. Pocket 8 x 16

10 / 63


BASIC DATA TO ESTIMATE NUMBER OF STAGES

4.- BASIC DATA TO ESTIMATE NUMBER OF STAGES

Tables 3 through 6 show how one stage configuration is appropriate for handling

natural gas with a compression ratio of (800 + 14.3) / (250 + 14.3) = 3.081.

Adiabatic discharge temperature 266 °F is acceptable when compared against

API 11P 350 °F limit.

11 / 63



Table 3.- Basic Data to Estimate Number of Stages

Ps 250 psig

Pd 800 psig

Ts 100 ºF

ΔT COOLER 20 ºF

k 1.3 Assumption

Patm 14.3 Psia

Td max 350 ºF

η ISEN 0.85 Assumption

Zs 0.94 Guess

Zd 0.93 Guess

12 / 63



Table 4.- Thermodynamic Ecuations to Predict Discharge Temperature and Number of Stages

ADIABATIC NON-ADIABATIC 1 NON ADIABATIC 2

ExpRT =

−+=

η11

ExpRT ZRT

Exp

=

TRExpn

lnln⋅= ( )[ ]11ln

ln+−

⋅=T

RExpnη ( )TZ

RExpnln

ln⋅=

Where:

n = number of compression stages k

kExp 1−=

460460

++

=s

d

TT

T atms

atmd

PPPP

R++

= s

d

ZZ

Z =

13 / 63


5.- NUMBER OF STAGES AND DISCHARGE TEMPERATURE

Table 5.- Number Of Stages (n). Adiabatic And Non Adiabatic Models

Model Theoretical Number of Stages Adiabatic 0.70

n, Non Adiabatic 1 0.81 n, Non adiabatic 2 0.73

Table 6.- Discharge Temps – Second Stage

Number of Stages 1 2

Compression Ratio 3.081 1.755

Td Adiabatic ºF 266 200

Td Non Adiabatic1 ºF 295 215

Td Non Adiabatic2 ºF 274 208

14 / 63


BASIC PERF. MAPS ANALYSIS – PWR & FLOW

6.- BASIC PERFORMANCE MAPS ANALYSIS – POWER AND FLOW

Existing Case 1 (Attachment 1)

Attachment 1 Figure 1 shows the total power this reciprocating compressor

consumes in the analisis range. An examination of curves profile indicates 1- the

cylinders sizes are small for the power available and 2- the flow is aprox. 11.5

MMSCFD at nominal pressures. A simple appreciation of Fig. 1 can erroneously

lead to conclude this compressor is suitable for suction pressures around 400 PSI

and discharge pressures of around 1000 PSI.

However, a breakdown of the gas power into the two stage/cylinders (see Figure

2), reveals how at full load and nominal pressures (250 x 800 psi) first stage

absorves 740 HP while second stage absorves only 150 HP thus creating a

thermodynamic unbalance.

15 / 63



Existing Case 1 (Attachment 1) – Cont´d

This thermodynamic unbalance translates to a unbalanced torque regime with

likely high torque stresses on the crankshaft and undesirable torque pulsations in

the gas engine side.

This load unbalance increases the risk of cranckshaft failure in both compressor

and engine side during upset process conditions or speed changes. Engine

cylinders power balance is difficult to achieve, as per operators´ story.

Further increase of suction pressure makes this unbalancing worse. Rated

maximum power per cylinder was established by the OEM at 594 HP.

16 / 63




Existing Case 2 in Attachment 2 shows how cylinder 1 variable volume pocket is

uncapable of controling cylinder 1 power across the operating range. Beyond

suction pressure 250 PSIG the absorved power cannot be kept below 594 HP

because the stage 2 flow reverses. At its own, cylinder 2 absorved power is 190

HP with a diverging profile with respect to cylinder 1. Flow decreases to 10

MMSCFD.

Something has to be done to equalize cylinder 1 and cylinder 2 load regime, IE

further unloading of cylinder 1, which is the next analysis case.

17 / 63



Remedial Case (Attachment 3)

Remedial Case equalizes C1 and cylinder 2 absorved power as shown in

Attachment 3. At nominal pressure conditions (250 x 800 PSI) cylinders 1 and 2

consume roughly 260 HP each. Flow further decreases to 7 MMSCFD.

Revamp Case ( Attachment 4)

Attachment 4 ilustrates how Revamp Case maximizes and completely equalizes

both cylinders absorved power, allowing complete controlability of the power

across and beyond the operating range. The flow increased to 15.4 MMSCFD

with good reliability. Both variable volume pockets were sized as to have the

same setting across the operating range, thus improving operability.

18 / 63



Case Summary

Power and flow regimes belonging to the different analysis scenarios are

organized in Table 7 for quick reference.

Case 1 handles a significant flow but, as stated above, has an unaceptable power

unbalance.

Case 2 mitigates the power unbalance with 15% penalty in flow, but still the

picture is bad.

Case 3 illustrates how difficult is to balance this machine by means of unloading

cylinder 1. The flow decreases 60 % which is a high price to pay in terms of

revenues.

19 / 63



Case Summary – Cont´d

Case 4 represent the full solution together with the highest investment

(replacement of the two cylinders). It is expected that an increase in the reliability

and throughput would return the investment in the midterm.

Table 7.- Case Summary. Power and Flow

ANALYSIS CASE TOTAL POWER POWER PER CYLINDER FLOW

HP HP/CYL 1 HP/CYL 2 MMSCFD

1 Existing 1 890 740 150 11.5

2 Existing 2 784 594 190 10.0

3 Remedial 520 260 260 7.0

4 Revamp 1,188 594 594 15.4

20 / 63


SPECIAL PURPOSE PERF. MAPS ANALYSIS

7.- SPECIAL PURPOSE PERFORMANCE MAPS ANALYSIS Existing Case 1 (Attachment 5) As mentioned in 3, there is a problem with rod 2 which load remains in tension

(does not reverses) when the overall compression ratio increases due to pressure

fluctuations. See Attachment 5 Figure 10. Similarly, high discharge temperature

becomes a concern when overall compression ratio increases. See Figure 11.

Other key parameters as low volumetric efficiency and rod load have a good

picture as shown in Attachment 5 Figures 8 and 9.

21 / 63




Existing Case 2 represents a concern with rod load reversal when the

compression ratio decreases. Attachment 6 Figure 14 shows this situation and

suggests that with discharge pressures around 770 PSI, there might be a reversal

problem. At 320 PSI suction pressure the operating point crosses the boundary to

the prohibited zone for rod load reversal.

At its own, discharge temperature becomes a concern when the compression

ratio increases. See Attachment 6 Figure 15. 200 x 900 PSI network conditions

are clearly indicated as bordeline. Further increase of discharge pressure beyond

900 PSI can pose a problem. In such a operating region, the variable volume

pocket settings cross the boundary to the prohibited zone.

22 / 63



Remedial Case (Attachment 7)

Low volumetric efficiency and rod load show a good picture as depicted by

Figures 12 and 13. No thresholds are observed in the analysis range.

As expected, low volumetric efficiency regime becomes a problem within this

scenario because of the unloading provided to cylinder 1. Particularly evident is

the situation for the crank end discharge corner of this cylinder as depicted by

Figure 16: at higher pressure ratios the operating point crosses the boundary to

the prohibited zone. In the 800 – 900 PSI Pd range and 200 – 220 PSI Ps range,

one can expect to have low volumetric efficiency problems.

23 / 63



Remedial Case (Attachment 7) – Cont´d

The solution for the low volumetric efficiency problem would come in terms of

closing the variable volume pocket to 13” in order to be safe before the discharge

pressure fluctuations. The penalty would come in terms of power unbalance

between cylinder 1 and cylinder 2. As depicted in Attachments 1 & 2.

Figure 17 confirms the warnings from Figure 16: high pressure ratios create

cylinder 1 CE discharge low volumetric efficiency problems.

Rod load poses no concerns to the operator, as shown in Figures 18 and 19.

24 / 63



Remedial Case (Attachment 7) – Cont´d

Rod load reversal has problems at low compression ratios: See in Figure 20 how

the operating point in the 700 – 820 PSI discharge pressure range crosses the

prohibited threshold. There is no way to improve this situation via pocket setting.

The solution is to increase the pressure ratio.

Discharge temperatures show no thresholds of concern in the analysis range. It

can be seen in Figure 21 and 22. The closest boundary is 300 °F cylinder 2 but it

is not of concern because it needs a fairly high compression ratio as to be

trespassed.

At nominal suction pressure (250 PSI), the required discharge pressure as to

produce high discharge temperature in cylinder 2, is aproximately 1,200 PSI.

25 / 63



Revamp Case ( Attachment 8)

Being a revamp case, one would expect to have no concerns on mechanical

limits affecting the reliability. However as a borderline application (two stages

instead of one, see Tables 5 & 6) some thermodynamic limits should surround

the operating range. This can be observed in Attachment 8 as stated next.

Figure 23 depicts a 900 PSI low volumetric efficiency threshold at low suction

pressures withing the operating range. One should not open too much the

variable volume pocket because it will create a low volumetric efficiency regime

at a discharge pressure of 900 PSI.

Rod overload and load reversal are not a concern within this revamp case as

shown in Figures 24 & 25.

26 / 63



Revamp Case ( Attachment 8) – Cont´d

Cylinder 2 high discharge temperature is attainable only at high pressure ratios in

the vicinity of the operating range. This can be seen graphically in Figure 26,

where one can have high discharge temp below 180 PSI suction pressure. In the

event it happens, then one can mitigate the problem by further opening the

pocket (unloading the compressor).

27 / 63


CONCLUSIONS

8.- CONCLUSIONS

Total absorved power can be a misleading parameter as to characterize the

power rating of a multistage reciprocating compresor. It is necessary to plot the

individual cylinders power in order to have a complete picture for the power

balance within the compressor, which translates into a torque balance on the

crankshaft and driver side.

The analysis cases presented here showed how a wrongly sized cylinders

(cylinders too small) within a wrongly configured staging (two stages instead of

one) led to a thermodynamically unbalance stages (different power

consumptions, flow reversal).

Multistage compressors require unloading mechanisms in all stages in order to

appropriately distribute the load across the operating range.

28 / 63


CONCLUSIONS

Basic performance maps and special purpose performance maps as those

contained in the attachments are of special usefullness when it comes to the

diagnostic and optimization of reciprocating compressors.

29 / 63


EXISTING CASE 1 – BASIC PERF. MAPS

ATTACHMENT 1

EXISTING CASE 1 – BASIC PERFORMANCE MAPS

Tlf: +58.212.816.5779 Caracas, Venezuela www.turbodina.com Móvil: +58.414.247.1337 Orlando, Florida [email protected]

30 / 63 30 / 63 30 / 63



6

11

16

21

26

31

0

100

200

300

400

500

600

700

800

900

1000

1100

1200

1300

100 150 200 250 300 350 400

Tota

l Abs

orve

d Po

wer

-gh

p

Suction - psig

Zap Station, Compressor K3, Cylinders C1 & C2Total Power and Flow @ 300 RPM

Avail. Pwr. 1,188 ghp

Total GHP

Fluctuation

Flow

-M

MSC

FD @

14.

3 ps

ia &

60

ºF

Pd 900#

800

700

700 - 900# Pd

Flow

Fig. 1

Existing Case 1. C1 Var. Vol. Pocket Closed

31 / 63



Zap Station, Compressor K3, Cylinders C1 & C2Power and Flow @ 300 RPM

-700

-600

-500

-400

-300

-200

-100

0

100

200

300

400

500

600

700

800

900

1000

1100

100 150 200 250 300 350 400Suction - psig

Abs

orve

d Po

wer

Per

Cyl

- ghp

/cyl

6

11

16

21

26

31

Avail. Pwr. 594 ghp/cyl

GHP/cyl

Fluctuation

Flow

- M

MSC

FD @

14.

3 ps

ia &

60

ºF

Cyl 1, 700 - 900 # Pd

Pd 900#

800700

700 - 900# PdFlow

Cyl 2

Fig. 2

Existing Case 1. Var. Vol. Pocket Closed

GHP/cyl

32 / 63



ATTACHMENT 2

EXISTING CASE 2 - BASIC PERFORMANCE MAPS


33 / 63 33 / 63 33 / 63



Zap Station, Compressor K3, Cylinders C1 & C2Power and Flow - 300 RPM

-400

-300

-200

-100

0

100

200

300

400

500

600

700

100 150 200 250 300 350 400Suction - psig

Abs

orve

d Po

wer

Per

Cyl

- gh

p/cy

l

5

10

15

20

25


Power/cyl

Flow

- M

MSC

FD @

14.

3 ps

ia &

60

ºF

C1

C2Pd 900 #

800700

Flow700 - 900

Fluctuation

Fig. 7

700 - 900# Pd

Exist. Case 2. Match Available Power w/C1 Var. Vol. Pocket

Fig. 3

34 / 63



Zap Station, Compressor K3, Cylinders C1 & C2Flow & Var. Vol. Pocket - 300 RPM

-10

-5

0

5

10

15

100 150 200 250 300 350 400 Suction - psig

Flow

- m

msc

fd -

14.3

psi

a &

60

ºF

0

2

4

6

8

10

12

14

16

18

20

22

24

26

28

30

32

34

36

38

40

C1

Var.

Vol.

Pock

et -

Inch

Flow

900 # Pd

Fluctuation

Var. Vol Pocket

Máx. VV Pocket 16"

700 - 900 # Pd

Fig. 8

700


Fig. 4

35 / 63


REMEDIAL CASE – BASIC PERF. MAPS

ATTACHMENT 3

REMEDIAL CASE - BASIC PERFORMANCE MAPS


36 / 63 36 / 63 36 / 63


REMEDIAL CASE – BASIC PERF. MAPS

Zap Station, Compressor K3, Cylinders C1 & C2Power & Flow - 300 RPM

-400

-300

-200

-100

0

100

200

300

400

500

600

700

100 150 200 250 300 350 400Suction - Psig

Abs

orve

d Po

wer

Per

Cyl

. - G

hp/C

yl

2

7

12

17

22

Flow

MM

SCFD

@ 1

4.3

Psia

& 6

0°F

700800900

C2

(900, 800, 700)

Fluctuation

900

800

700

Flow

Power


Fig. 13

Remedial Case. C1 Var. Vol. Pocket Fully Open + 75% C1 CE Bottle

C1

Fig. 5

37 / 63


REVAMP CASE – BASIC PERF. MAPS

ATTACHMENT 4

REVAMP CASE - BASIC PERFORMANCE MAPS


38 / 63 38 / 63 38 / 63



468101214161820222426283032343638404244464850

300

350

400

450

500

550

600

650

100 150 200 250 300 350 400

Flow

-m

msc

fd @

14,

3 ps

ia &

60

°F

Abso

rved

Pow

er P

er C

yl -

Ghp

/Cyl

Suction - Psig

Zap Station, Compressor K3, Cylinders C1 & C2Power & Flow - 300 RPM

800Fluctuation

Flow

Power Cyl 2 or Cyl 3

900

700

900

700

Avail. Pwr. 594 GHP/cyl

See VV Pockets in graph 7

Revamp Case. Cyl 1 13.5" / Cyl 2 10.5" w/VV Pockets 800

900 700800

Fig. 6

39 / 63



012345678910111213141516171819202122232425

02468

1012141618202224262830323436384042444648505254565860

100 150 200 250 300 350 400

Flow

MM

SCFD

-14

,3 P

sia,

60°

F

Var.

Vol.

Pock

ets

-Inc

h

Suction - Psig

Zap Station, Compressor K3, Cylinders C1 & C2Flow and C1 & C2 Var Vol Pockets - 300 RPM

800900

Fluctuation

Flow

700

See Pwr in a separate graph

VV Pockets C1 & C2

900

800

700Revamp Case. Cyl 1 13.5" / Cyl 2 10.5" w/VV Pockets

Fig. 7

40 / 63


EXISTING CASE 1 – SPECIAL PURPOSE MAPS

ATTACHMENT 5

EXISTING CASE 1 – SPECIAL PURPOSE PERFORMANCE MAPS



41 / 63



0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

5500

6000

100 150 200 250 300 350 400

Dis

char

ge -

Psig

Suction - Psig

Zap Station, Compressor K3, Cylinders C1 & C2Low Vol. Eff. Thresholds - 300 RPM

Fluctuation

Prohibited Zone

Permitted Zone

Fig. 8


C2 HE Disch.

C2 CE Disch.

Nom. Pd 800 #

(Hypotetical Plot)

42 / 63



0

500

1000

1500

2000

2500

3000

3500

4000

4500

100 150 200 250 300 350 400

Dis

char

ge -

Psig

Suction - Psig

Zap Station, Compressor K3, Cylinders C1 & C2Rod Overload Thresholds - 300 RPM

Fluctuation

Prohibited Zone

Permitted Zone

Oper. Region

Fig. 9

100 KLBF Thresholds Cyl 2 Traction

Compression


(Hypotetical Plot)

43 / 63



0

200

400

600

800

1000

1200

100 150 200 250 300 350 400

Dis

char

ge -

Psig

Suction - Psig

Zap Station, Compressor K3, Cylinders C1 & C2Rod Load Reversal Thresholds - 300 RPM

Permitted Zone

Prohibited Zone Oper. Region

Fluctuation

Compression

Traction

Fluc

t.C2 Thresholds

Fig. 10


44 / 63



500

600

700

800

900

1000

1100

100 150 200 250 300 350 400

Dis

char

ge -

Psig

Suction - Psig

Zap Station, Compressor K3, Cylinders C1 & C2High Disch. Temp. Threshold - 300 RPM

Prohibited Zone Permitted Zone

Oper. Regions

300 ºF Threshold Cyl 2

Fluctuation

Fluc

t.

Fig. 11


45 / 63



ATTACHMENT 6

EXISTING CASE 2 - SPECIAL PURPOSE PERFORMANCE MAPS


46 / 63



0

5

10

15

20

25

30

35

40

45

50

55

60

100 150 200 250 300 350 400

C1

Var.

Vol.

Pock

et -

Inch

Suction - Psig

Zap Station, Compressor K3, Cylinders C1 & C2Low Volumetric Eff. Thresholds - 300 RPM

Fluctuation

Prohibited Zone

Permitted Zone

900

800

700

Máx. VV Pocket Setting 16"

Fig. 12

Low VE Thresholds C1 Disch. HE

Exist. Case 2. Match Available Power w/C1 Var. Vol. Pocket (Hypotetical Plot)

VV Pocket Setting

47 / 63



0

5

10

15

20

25

100 150 200 250 300 350 400

C1

Var.

Vol.

Pock

et S

ettin

g -I

nch

Suction - Psig

Zap Station, Compressor K3, Cylinders C1 & C2Rod Overload Thresholds. 300 RPM

No thresholds are observed in the analysis

range

Fig. 13

Internal Gas Loads Only


Máx. VV Pocket Setting 16"

VV Pocket Setting

48 / 63



0

5

10

15

20

25

30

35

40

100 150 200 250 300 350 400

C1

Varia

ble

Volu

me

Pock

et S

ettin

g -I

nch

Suction - Psig

Zap Station, Compressor K3, Cylinders C1 & C2Rod Load Reversal - 300 RPM

Fluctuation

Prohibited Zone

Permitted Zone

900

800

700

Fig. 14

C2 Thresholds Interna Gas Loads Only

Máx. Var. Vol. Pocket Setting 16"


VV Pocket Setting

49 / 63



0

5

10

15

20

25

30

100 150 200 250 300 350 400

C1

Varia

ble

Volu

me

Pock

et S

ettin

g -I

nch

Suction - Psig

Zap Station, Compressor K3, Cylinders C1 & C2High Discharge Temp. Thresholds - 300 RPM

Fluctuation

Prohibited Zone

Permitted Zone

700 900800

Fig. 15

Máx. Var. Vol. Pkt Setting 16"

C2 300°F Disch. Temp. Thresholds


VV Pocket Setting

50 / 63


REMEDIAL CASE – SPECIAL PURPOSE MAPS

ATTACHMENT 7

REMEDIAL CASE - SPECIAL PURPOSE PERFORMANCE MAPS


51 / 63



0

5

10

15

20

25

30

100 150 200 250 300 350 400

C1

Varia

ble

Vol.

Pock

et -

Inch

Suction - Psig

Zap Station, Compressor K3, Cylinders C1 & C2Low Volumetric Efficiency Thresholds - 300 RPM

900#800#700#Prohibited Zone

Permitted Zone

FluctuationLow VE C1 CE Disch.

Max. Var. Vol. Pocket Opening 16"

Fig. 16

Remedial Case. C1 Var. Vol. Pocket fully Open + 75% C1 CE Bottle

900#800#700#

C1 Var Vol Pocket Setting

52 / 63



Zap Station, Compressor K3, Cylinders C1 & C2Low Volumetric Efficiency Thresholds - 300 RPM

400

500

600

700

800

900

1000

1100

1200

100 150 200 250 300 350 400 Suction - Psig

Dis

char

ge -

Psig

Fluctuation

Permitted ZoneProhibited Zone

Fluctuation

Oper. Region

C1 CE Disch. ThresholdRemedial Case. C1 Var. Vol. Pocket Fully Open + 75% C1 CE Bottle

Fig. 15Fig. 17

53 / 63



Zap Station, Compressor K3, Cylinders C1 & C2Rod Overload Thresholds. 300 RPM

0

400

800

1200

1600

2000

2400

2800

3200

3600

4000

100 150 200 250 300 350 400 Suction - Psig

Dis

char

ge -

Psig

Fluctuation

Permitted Zone

Prohibited Zone

Fluctuation Oper. Region

100 KLBF C2 ThresholdOnly Internal Gas Load

Fig. 16


Fig. 18

54 / 63



0

2

4

6

8

10

12

14

16

18

20

100 150 200 250 300 350 400

C1

Varia

ble

Volu

me

Pock

et -

Inch

Suction - Psig


No thresholds are observed in the analysis range

Fig. 19

internal gas load only

Max. Var. Vol. Pocket Opening 16"

FluctuationRemedial Case. C1 Var. Vol. Pocket fully Open + 75% C1 CE Bottl


55 / 63



0

5

10

15

20

25

100 150 200 250 300 350 400

C1

Var.

Vol.

Pock

et S

ettin

g -I

nch

Suction - Psig

Zap Station, Compressor K3, Cylinders C1 & C2Rod Load Reversal Thresholds. 300 RPM

800 #

900 #

Max. Var. Vol. Pocket Setting 16"

Fluctuation

Permitted Zone

Prohibited Zone

Fig. 20

C2 Thresholds Internal Gas Load

Only

700 #Remedial Case. C1 Var. Vol. Pocket fully Open + 75% C1 CE Bottle


56 / 63



0

5

10

15

20

25

100 150 200 250 300 350 400

C1

Varia

ble

Volu

me

Pock

et S

ettin

g -I

nch

Suction - Psig



Fig. 21

Remedial Case. C1 Var. Vol. Pocket Adjusted + 75% C1 CE Bottle

Max. Var. Vol. Pocket Setting 16"


Fluctuation

57 / 63



500

600

700

800

900

1000

1100

100 150 200 250 300 350 400

Dis

char

ge -

Psig

Suction - Psig


Fluctuation

Permitted ZoneProhibited Zone

300° F C2 Threshold

FluctuationOper. Region

Fig. 22


58 / 63


REVAMP CASE – SPECIAL PURPOSE MAPS

ATTACHMENT 8

REVAMP CASE - SPECIAL PURPOSE PERFORMANCE MAPS


59 / 63



0

5

10

15

20

25

30

100 150 200 250 300 350 400

C1

& C

2 Va

r. Vo

l. Po

cket

s -I

nch

Suction - Psig

Zap Station, Compressor K3, Cylinders C1 & C2Low Vol. Eff. Thresholds - 300 RPM

Fluctuation


No thresholds are observed for Pd = 800 & 700#

Máx VVP Setting 21"

C2 ThresholdsHE Disch.

900#

No thresholds are observed in the C1 corners

Revamp Case. Cyl 1 13.5" / Cyl 2 10.5" w/VV Pockets

Fig. 23

Var Vol Pocket Setting

800900 700

60 / 63



0.0

5.0

10.0

15.0

20.0

25.0

100 150 200 250 300 350 400

C1

& C

2 Va

r Vol

Poc

kets

-In

ch

Suction - Psig



Only internal gas loads


Fig. 24

Fluctuation


800900 700


61 / 63



0.0

5.0

10.0

15.0

20.0

25.0

100 150 200 250 300 350 400

C1

& C

2 Va

r. Vo

l. Po

cket

s -I

nch

Suction - Psig

Zap Station, Compressor K3, Cylinders C1 & C2Rod Load Reversal Thresholds - 300 RPM


Only Internal Gas Loads


Fig. 25

Fluctuation


800900 700


62 / 63



0

5

10

15

20

25

30

100 150 200 250 300 350 400

C1

& C

2 Va

r. Vo

l. Po

cket

s -

Inch

Suction - Psig

Zap Station, Compressor K3, Cylinders C1 & C2High Disch. Temp. Thresholds - 300 RPM

900 #

C2 300 oF Thresholds Max. VV Pockets Setting 21"


No thresholds are observed for Pd = 700 & 800#


Fluctuation

Fig. 26


800900 700

63 / 63

wrong sizing of a reciprocating compressor

Education

recip compressor rev

wrong sizing

compressor data

existing case

remedial case

revamp case

history case

case summary