selecting a reciprocating or centifugal compressor

63
© 2012 Valerus. Confidential and proprietary. All rights reserved. © 2012 Valerus. Confidential and proprietary. All rights reserved. Compression Split – Technical Seminar September 26, 2013 Tom Birney, Director of Business Development

Upload: herve-baron

Post on 16-Apr-2017

868 views

Category:

Engineering


3 download

TRANSCRIPT

Page 1: Selecting a reciprocating or centifugal compressor

© 2012 Valerus. Confidential and proprietary. All rights reserved. © 2012 Valerus. Confidential and proprietary. All rights reserved.

Compression Split – Technical Seminar

September 26, 2013

Tom Birney, Director of Business Development

Page 2: Selecting a reciprocating or centifugal compressor

© 2012 Valerus. Confidential and proprietary. All rights reserved. © 2012 Valerus. Confidential and proprietary. All rights reserved.

OVERVIEW

Page 3: Selecting a reciprocating or centifugal compressor

© 2012 Valerus. Confidential and proprietary. All rights reserved.

OUTLINE

1. Selection Of A Reciprocating Or Centrifugal Compressor a. Parameters b. Drivers c. Centrifugal Compressors d. Reciprocating Compressors d. Recip. vs. Centrifugal Comparison - Examples e. Conclusion

Page 4: Selecting a reciprocating or centifugal compressor

© 2012 Valerus. Confidential and proprietary. All rights reserved.

OUTLINE

2. High/Medium Speed Vs. Slow Speed Comparison of API 11P (ISO-13631): High/medium speed compressors and API 618 slow speed compressors

3. Sizing, Selection and Applications

4. Packaging Considerations

Page 5: Selecting a reciprocating or centifugal compressor

© 2012 Valerus. Confidential and proprietary. All rights reserved. © 2012 Valerus. Confidential and proprietary. All rights reserved.

COMPRESSION 1. Selection of a Reciprocating or Centrifugal Compressor

Page 6: Selecting a reciprocating or centifugal compressor

© 2012 Valerus. Confidential and proprietary. All rights reserved.

COMPRESSOR TYPES

Rolling Lobe (Roots)

Reciprocating

Single Screw

Axial

Liquid Ring

Screw

Vane

Radial

Positive Displacement Dynamic

Page 7: Selecting a reciprocating or centifugal compressor

© 2012 Valerus. Confidential and proprietary. All rights reserved.

HISTORY

Page 8: Selecting a reciprocating or centifugal compressor

© 2012 Valerus. Confidential and proprietary. All rights reserved.

DEFINE THE QUESTION

• Plant or Site Parameters

• Project Parameters

• Process Parameters

• Machinery Parameters

Page 9: Selecting a reciprocating or centifugal compressor

© 2012 Valerus. Confidential and proprietary. All rights reserved.

PLANT OR SITE PARAMETERS

• Onshore / Offshore

• Elevation/Barometric Pressure

• Ambient Temperature - design/range

• Fuel Available - type, pressure, cost

• Soil/Foundation conditions

• Enclosure Required - open, partial, full

• Manpower/Staffing Plans

• Utilities - water, power, air

• Environment - noise, air, effluents

Page 10: Selecting a reciprocating or centifugal compressor

© 2012 Valerus. Confidential and proprietary. All rights reserved.

PROJECT PARAMETERS

• Anticipated life

• Required start up date & equipment deliveries

• Economic evaluation criteria

Page 11: Selecting a reciprocating or centifugal compressor

© 2012 Valerus. Confidential and proprietary. All rights reserved.

PROCESS PARAMETERS

• Gas analysis

• Suction pressure - design/range

• Discharge pressure - design/range

• Suction temperature - design/range

• Flow rate - design/range

• Extra process heat requirement

• Operating flexibility required

• Operating reliability required

Page 12: Selecting a reciprocating or centifugal compressor

© 2012 Valerus. Confidential and proprietary. All rights reserved.

MACHINERY PARAMETERS

• Initial cost

• Transportation/installation cost & time

• Compressor efficiency - kw/m3

• Specific fuel consumption over range

• Power avail/power required match

• Actual emissions/emissions allowed

• Operation & maintenance cost

• Flexibility to handle range of conditions

Page 13: Selecting a reciprocating or centifugal compressor

© 2012 Valerus. Confidential and proprietary. All rights reserved.

ELECTRIC OR GAS DRIVER

• Fuel gas availability & quality

• Electricity availability

• Speed control

• Fuel gas vs electric cost

• Maintenance vs initial cost

• Emissions

• Lead time

Page 14: Selecting a reciprocating or centifugal compressor

© 2012 Valerus. Confidential and proprietary. All rights reserved.

• Fuel gas availability & quality – Not Required

• Electricity availability - Required

• Speed control – Additional VFD and Torsional Analysis

• Fuel gas vs electric cost – varies

• Maintenance vs initial cost – Maintenance Low / (high failure cost)

Initial cost comparable

• Emissions - None

• Lead time – Long, built to order

ELECTRIC DRIVER

Page 15: Selecting a reciprocating or centifugal compressor

© 2012 Valerus. Confidential and proprietary. All rights reserved.

• Two types of gas turbines – Industrial

• steam turbine technology • in-situ repair

– Aero-derivative • replace - don’t repair

COMBUSTION GAS TURBINE

Page 16: Selecting a reciprocating or centifugal compressor

© 2012 Valerus. Confidential and proprietary. All rights reserved.

• Fuel gas availability & quality –Required / high quality

• Electricity availability - No

• Speed control – Usually ran at constant speed

• Fuel gas vs electric cost – varies

• Maintenance vs initial cost – Maintenance Low / (high failure cost)

Higher Initial cost

• Emissions - High

• Lead time – Long

TURBINE DRIVER

Page 17: Selecting a reciprocating or centifugal compressor

© 2012 Valerus. Confidential and proprietary. All rights reserved.

• Complex start-up/stop sequencing • Complex controls required for fuel scheduling and emissions

controls • Many critical monitoring points for gas turbine • Complicated surge control

GAS TURBINE CONTROLS

Page 18: Selecting a reciprocating or centifugal compressor

© 2012 Valerus. Confidential and proprietary. All rights reserved.

• Fuel gas availability & quality –Required / low quality

• Electricity availability - No

• Speed control – Included

• Fuel gas vs electric cost – varies

• Maintenance vs initial cost – Maintenance medium / Low Initial cost

• Emissions - medium

• Lead time – short

RECIPROCATING ENGINE DRIVER

Page 19: Selecting a reciprocating or centifugal compressor

© 2012 Valerus. Confidential and proprietary. All rights reserved.

• Industry did not have a large industrial gas engine until 1995. – Caterpillar G3616 in 1995 (4500 HP) – Caterpillar G16CM34 in 2001 (7670 HP) – Waukesha 16V-AT27 in 2000 (4500 HP) – Wartsila 18V34SG in 1997 (8000 HP) – Wartsila 20V34SG in 1998 (10600 HP)

RECIPROCATING DRIVERS

Page 20: Selecting a reciprocating or centifugal compressor

© 2012 Valerus. Confidential and proprietary. All rights reserved.

Turbine Engine

Available HP >30,000 >10,000

Temp. 22°C 37.8°C

Altitude Sea Level 1500m

Intake Loss None allowed 1500mm WC

Exhaust Loss None allowed 300mm WC

Degradation Allow up to 10% 0%

Weight / Footprint Low High

RECIPROCATING ENGINE VS. GAS TURBINES DRIVERS

Page 21: Selecting a reciprocating or centifugal compressor

© 2012 Valerus. Confidential and proprietary. All rights reserved.

CENTRIFUGAL COMPRESSORS

WHY Centrifugal? • Mature Technology – Since 1940’s • Handles large capacities • High Horsepower • Small footprint • 99% Availability • Minimal Maintenance

Page 22: Selecting a reciprocating or centifugal compressor

© 2012 Valerus. Confidential and proprietary. All rights reserved.

CENTRIFUGAL CHARACTERISTICS

• Dynamic compressor Achieves pressure increase by controlling gas velocities

• Narrow operating range Precise matching to design point

• Minimal degree of capacity control\ • Large Volumetric flow rates

Page 23: Selecting a reciprocating or centifugal compressor

© 2012 Valerus. Confidential and proprietary. All rights reserved.

Flow: Minimum flow is approx. 3 m3/min (100 acfm) into any impeller. As flow decreases toward this limit efficiency falls off dramatically.

CENTRIFUGAL COMPRESSOR APPLICATION LIMITATIONS

Page 24: Selecting a reciprocating or centifugal compressor

© 2012 Valerus. Confidential and proprietary. All rights reserved.

CENTRIFUGAL COMPRESSOR APPLICATION LIMITATIONS

Pressure: • Lower limit, none with proper seals. • Upper limit, high discharge pressure not itself a limiting factor, just

thicker components. This may reduce number of stages possible. • Most applications are below 350 bar. • Higher suction pressure are more difficult to seal. Most applications

below 200 bar.

Page 25: Selecting a reciprocating or centifugal compressor

© 2012 Valerus. Confidential and proprietary. All rights reserved.

Temperature: • Low temps. down to -75°C handled using higher cost materials of

sufficient ductility. Special seals required. Upper limit set by shaft seals.

• Temps. of 195°C are common & can be increased to 230°C with cool buffer gas.

CENTRIFUGAL COMPRESSOR APPLICATION LIMITATIONS

Page 26: Selecting a reciprocating or centifugal compressor

© 2012 Valerus. Confidential and proprietary. All rights reserved.

CENTRIFUGAL COMPRESSOR APPLICATION LIMITATIONS

Compression Ratio or Head: • Determines the number of stages required. For dynamic compressors this is a function of pressure ratio, MW, temperature, compressibility and ratio of specific heats. Due to rotor stability 10 impellers is normal max. At 4,600 m kg/kg polytropic head per impeller this limits methane to 7.92 ratios in one casing and propane to 200 ratios. Correct MW is critical to proper selection.

Page 27: Selecting a reciprocating or centifugal compressor

© 2012 Valerus. Confidential and proprietary. All rights reserved.

CENTRIFUGAL COMPRESSOR APPLICATION LIMITATIONS

Horsepower: • Applications less than 750 kw (~1000 hp) usually have some other

limiting factor such as low flow or poor efficiency.

• Upper limits are typically set by available drivers.

• Centrifugal compressors can handle high powers.

Page 28: Selecting a reciprocating or centifugal compressor

© 2012 Valerus. Confidential and proprietary. All rights reserved.

CENTRIFUGAL COMPRESSOR APPLICATION LIMITATIONS

Rotative Speed: • With dynamic compressors higher speed results in improved

performance. Work per stage and flow increases with speed. Mechanical considerations limit tip speeds to 335 m/sec for open impellers and 425 m/sec for closed impellers.

Page 29: Selecting a reciprocating or centifugal compressor

© 2012 Valerus. Confidential and proprietary. All rights reserved.

CENTRIFUGAL COMPRESSOR APPLICATION LIMITATIONS

Efficiency: • Polytropic efficiency per stage of 85% is normal for quantity constant

of 100 to 300 and declines to 70% as quantity constant drops to 35. Quantity Constant = ICFM X 1000 X 1728 RPM X IMP. DIA. (in)

Page 30: Selecting a reciprocating or centifugal compressor

© 2012 Valerus. Confidential and proprietary. All rights reserved.

RECIPROCATING COMPRESSORS

WHY Reciprocating? • Large, operating range / flow / pressure / variations in gas • +95% Availability • Portability • Ease of Start – Stop • Re-Application • Cost

Page 31: Selecting a reciprocating or centifugal compressor

© 2012 Valerus. Confidential and proprietary. All rights reserved.

RECIPROCATING CHARACTERISTICS

• Positive Displacement compressor Achieves pressure by reducing the volume

• Wide operating range • Infinite capacity control • Efficiency improves with decreasing flow

Page 32: Selecting a reciprocating or centifugal compressor

© 2012 Valerus. Confidential and proprietary. All rights reserved.

RECIPROCATING COMPRESSOR APPLICATION LIMITATIONS

Flow: • No minimum flow. Maximum flow limited by piston displacement of

available cylinders.

Page 33: Selecting a reciprocating or centifugal compressor

© 2012 Valerus. Confidential and proprietary. All rights reserved.

Pressure: • No minimum limit, can attain high vacuums. Maximum pressures

can be ultra high for special processes. Separable applications are normally limited to 415 bar (6000 psi), at reduced rotative speeds.

RECIPROCATING COMPRESSOR APPLICATION LIMITATIONS

Page 34: Selecting a reciprocating or centifugal compressor

© 2012 Valerus. Confidential and proprietary. All rights reserved.

RECIPROCATING COMPRESSOR APPLICATION LIMITATIONS

Temperature: Minimum limit is -30°C with standard material and -40°C with special alloys. Maximum limit is normally 175°C and preferably below 150°C.

Page 35: Selecting a reciprocating or centifugal compressor

© 2012 Valerus. Confidential and proprietary. All rights reserved.

RECIPROCATING COMPRESSOR APPLICATION LIMITATIONS

Compression Ratio: • Normally limited by one of following;

Max. discharge temp. Allowable rod load Low cylinder volumetric efficiency

• Practical limits on natural gas are 4 - 5 on first stage and 3.5 - 4.5 on succeeding stages.

Page 36: Selecting a reciprocating or centifugal compressor

© 2012 Valerus. Confidential and proprietary. All rights reserved.

RECIPROCATING COMPRESSOR APPLICATION LIMITATIONS

Horsepower: • Limited by frame ratings or driver ratings. Reciprocating (aka Separable)

frames of 7500kw and gas engines of 6100 kw (8000 Bhp) are available.

Page 37: Selecting a reciprocating or centifugal compressor

© 2012 Valerus. Confidential and proprietary. All rights reserved.

RECIPROCATING COMPRESSOR APPLICATION LIMITATIONS

Rotative Speed: • Smaller compressors operate at speeds up to 1800 rpm with larger units in

the 750 - 1200 rpm range. Speed is normally determined by available driver speed.

Page 38: Selecting a reciprocating or centifugal compressor

© 2012 Valerus. Confidential and proprietary. All rights reserved.

SEPARABLE / CENTRIFUGAL COMPARISION

Comparing the most abundant combination in the upstream gas field. • Reciprocating Compressor driven by a Gas Engine : Separable

• Radial Compressor driven by a Gas Turbine : Centrifugal

Page 39: Selecting a reciprocating or centifugal compressor

© 2012 Valerus. Confidential and proprietary. All rights reserved.

SEPARABLE / CENTRIFUGAL COMPARISION

Coverage:

Page 40: Selecting a reciprocating or centifugal compressor

© 2012 Valerus. Confidential and proprietary. All rights reserved.

SEPARABLE / CENTRIFUGAL COMPARISION

Separable vs. Centrifugal Coverage:

Page 41: Selecting a reciprocating or centifugal compressor

© 2012 Valerus. Confidential and proprietary. All rights reserved.

SEPARABLE / CENTRIFUGAL COMPARISION

POWER COMPARISON:

3

2 1

Point Separable Centrifugal

1 5182kW 5660kW 2 5138kW 6129kW 3 4016kW 4685kW

Page 42: Selecting a reciprocating or centifugal compressor

© 2012 Valerus. Confidential and proprietary. All rights reserved.

SEPARABLE / CENTRIFUGAL COMPARISION

POWER COMPARISON:

Point Separable Centrifugal

1 5182kW 5660kW 2 5138kW 6129kW 3 4016kW 4685kW

DRIVER RATINGS: Derate

Temperature 37C 18% Altitude 260m 4%

GT intake losses 100mm 0.7% GT exhaust losses 100mm

• Gas Turbine Derate: 22% + 10% degradation • Gas Engine Derate: 0%

Page 43: Selecting a reciprocating or centifugal compressor

© 2012 Valerus. Confidential and proprietary. All rights reserved.

SEPARABLE / CENTRIFUGAL COMPARISON

POWER COMPARISION: Required Driver Rating (from Point 1): • Gas Engine rating required: 5182 kw

• ISO Gas Turbine rating required: 5660 ÷0.68 = 8323 kw

• Turbine rating needs to be 60%

more than gas engine rating to meet design flows

Solar Titan 130

Page 44: Selecting a reciprocating or centifugal compressor

© 2012 Valerus. Confidential and proprietary. All rights reserved.

SEPARABLE / CENTRIFUGAL COMPARISON

OPERATING COSTS: Fuel: • Cost of fuel is the single largest operating cost.

• Reciprocating uses 23% less fuel than the Gas Turbine.

Reciprocating Turbine

Site Rating 8.44 Mj/Kwh 10.09 Mj/Kwh Total 43736 Mj/hr 57109 Mj/jr

Page 45: Selecting a reciprocating or centifugal compressor

© 2012 Valerus. Confidential and proprietary. All rights reserved.

EFFICIENCY COMPARISON

Turbine / Centrifugal Engine / Reciprocating

Driver Heat Rate Btu / (hp-hr)

8239 6400 29%

Compressor Hp / MMSCFD

26.5 24.7 +7%

Decreasing Driver

Speed Increased Fuel Rate No Change or Decrease

Total Difference +36%

Page 46: Selecting a reciprocating or centifugal compressor

© 2012 Valerus. Confidential and proprietary. All rights reserved.

Reciprocating Compressor: – piston rings and wear bands 16000 hr – valve overhaul 8000 hr – packings 16000 hr – complete 70000 hr

• Engine – spark plugs 2000 hr – top end 30000 hr – complete 60000 hr

• Estimated cost $7.2/MWh

MAINTENANCE COMPARISON

Centrifugal Compressor: – minimal with high quality gas

• Gas Turbine – major overhaul 32000 hr

• Estimated Cost $6.4/MWh

Page 47: Selecting a reciprocating or centifugal compressor

© 2012 Valerus. Confidential and proprietary. All rights reserved.

AVAILABILITY

100%Downtime)dUnschedulefromLossesProduction(Actual

ProductionActualyReliabilit

100%scheduled) LossesdUnscheduleLossesProduction(Actual

ProductionActualtyAvailabili

Page 48: Selecting a reciprocating or centifugal compressor

© 2012 Valerus. Confidential and proprietary. All rights reserved.

AVAILABILITY

• Reciprocating Rental fleet operators guarantee 97 - 99% availability for separable units

• Rotating 99% expected for gas turbine / centrifugal

Page 49: Selecting a reciprocating or centifugal compressor

© 2012 Valerus. Confidential and proprietary. All rights reserved.

PIPELINE APPLICATION EXAMPLE ASSUMPTIONS

• 7500 Bhp installed • Heat rates (btu / (hp-hr))

– CAT 3616TA: 6810 – Wartsila 34SG: 6400 – Solar Taurus: 8239

• Fuel Cost: $2.5 / MM btu • Interest rate: 10% • Project life: 18 years

Page 50: Selecting a reciprocating or centifugal compressor

© 2012 Valerus. Confidential and proprietary. All rights reserved.

PIPELINE APPLICATION EXAMPLE

SOLAR CAT Wartsilla

Installed Cost $6,091,000 $5,642,000 $5,834,000

O&M ($/hp) 25 40 45

Yearly O&M ($) $200,000 $320,000 $360,000

Yearly Fuel ($) $1,160,000 $841,000 $909,000

NPV - O&M ($) $1,640,000 $2,624,000 $2,952,000

NPV - Fuel ($) $9,511,000 $6,896,000 $7,454,000

Life Cycle Cost ($) $17,242,000 $15,162,000 $16,240,000

% Difference 14% 0% 7%

Page 51: Selecting a reciprocating or centifugal compressor

© 2012 Valerus. Confidential and proprietary. All rights reserved.

PIPELINE APPLICATION EXAMPLE

0

50

100

150

200

250

300

350

Flo

w (

MM

SC

FD

)

Jan Mar May July Sept Nov

During Engineering / Design:

Page 52: Selecting a reciprocating or centifugal compressor

© 2012 Valerus. Confidential and proprietary. All rights reserved.

PIPELINE APPLICATION EXAMPLE

FlowMMSCFD

Suction PressurePSIA

Discharge PressurePSIA

305 550 900

300 564 900

290 590 900

280 615 900

250 678 900

225 722 900

During Engineering / Design:

Page 53: Selecting a reciprocating or centifugal compressor

© 2012 Valerus. Confidential and proprietary. All rights reserved.

PIPELINE APPLICATION EXAMPLE

Reciprocating

Centrifugal

Percent Flow0 20 40 60 80 100 120 140

Co

mp

res

sio

n R

ati

o

1.0

1.1

1.2

1.3

1.4

1.5

1.6

1.7

1.8

1.9

2.0

2.1

2.2

2.3

2.4

2.5

During Engineering / Design:

Page 54: Selecting a reciprocating or centifugal compressor

© 2012 Valerus. Confidential and proprietary. All rights reserved.

PIPELINE APPLICATION EXAMPLE

ACTUAL Operating Conditions:

Page 55: Selecting a reciprocating or centifugal compressor

© 2012 Valerus. Confidential and proprietary. All rights reserved.

PIPELINE APPLICATION EXAMPLE

Reciprocating

Centrifugal

Percent Flow 0 20 40 60 80 100 120 140

Co

mp

ressio

n R

ati

o

1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2.0 2.1 2.2 2.3 2.4 2.5

Design vs Actual:

Page 56: Selecting a reciprocating or centifugal compressor

© 2012 Valerus. Confidential and proprietary. All rights reserved.

PIPELINE APPLICATION EXAMPLE

Percent Flow

0 20 40 60 80 100 120 140

Co

mp

ressio

n R

ati

o

1.0

1.1

1.2

1.3

1.4

1.5

1.6

1.7

1.8

1.9

2.0

2.1

2.2

2.3

2.4

2.52 Reciprocating

Units Reciprocating

1 Reciprocating Unit

Centrifugal

Design vs Actual:

Page 57: Selecting a reciprocating or centifugal compressor

© 2012 Valerus. Confidential and proprietary. All rights reserved.

OTHER CONSIDERATIONS

gas turbine driven

centrifugal compressor

gas engine driven reciprocating

compressor

operating pressure

not flexible, has very limited pressure ratio

very flexible, can be designed to cover broad range of pressures

flow capacity typical 100%-60% with variable guide vanes Large Capacity

typically 100% - 50% with clearance control

100%-0% with recycle 100%-0% with recycle

gas gravity pressure ratio is sensitive to the gas gravity

pressure ratio is not affected by the gas gravity

modification not practical to modify for changing gas conditions

can be modified for # stages and changing gas types and flows

cannot readily change pressure ratio can be designed as 1 stage / 2 stage or 2 stage/3 stage, etc

size, weight small and compact larger and heavier than centrifugal available in large powers but similarly sized standby needed if the service is critical

Above about 4700 hp would require multiple units but costs and flexibility are improved

Page 58: Selecting a reciprocating or centifugal compressor

© 2012 Valerus. Confidential and proprietary. All rights reserved.

OTHER CONSIDERATIONS

gas turbine driven centrifugal

compressor

gas engine driven reciprocating

compressor

cost usually higher capital cost usually lower capital cost

fuel consumption 3 - 4 times higher than gas engine as low as 6800 - 8000 btu/bhp/hr usually requires fuel conditioning for field gases tolerant of field gases

reliability typically 99 - 99.8% typically 95-98.5% needs sophisticated controls and instrumentation

off the shelf control and instrumentation

maintenance requires special shop repair and skilled technicians

common tools and oil-field mechanics

usually requires special synthetic lubricants

Uses locally available engine crankcase lubricants

requires special tools and assembly fixtures

common tools and assembly techniques

parts low usage, high cost predictable usage, low cost special parts, expensive insurance spares common parts, no insurance spares

Page 59: Selecting a reciprocating or centifugal compressor

© 2012 Valerus. Confidential and proprietary. All rights reserved.

OTHER CONSIDERATIONS

gas turbine driven centrifugal

compressor

gas engine driven reciprocating

compressor

failure modes can be unexpected and catastrophic usually with early symptoms and limited to replaceable components

delivery Can be very long 9 - 18 months Can be very short 14 - 36 weeks

installation small footprint and close centerlines larger footprint

unbalance and vibration are nil unbalanced forces and moments are low

typically 4 - 8 weeks typically a few days to a week

portability usually not portable since the compressor is designed for a specific set of conditions and gas

below about 2,000 hp can operate without foundation

site rating turbines lose power generally above 500 ft

turbocharged gas engines maintain power up to about 5,000 ft

Page 60: Selecting a reciprocating or centifugal compressor

© 2012 Valerus. Confidential and proprietary. All rights reserved.

RECIPROCATING / CENTRIFUGAL COMPARISON

Compressor Type Separable Centrifugal kw/m3 1 3 Installed cost 1 2 Lead time 1 3 Fuel consumption 1 2 Waste heat avail. 3 1 Availability 2 1 O & M cost 2 1 Low emissions 2 2 Operating flexibility 1 3

Compare a natural gas engine driven separable compressor to a gas turbine driven centrifugal compressor.

1 = best 2 = not quite as good 3 = worst

Page 61: Selecting a reciprocating or centifugal compressor

© 2012 Valerus. Confidential and proprietary. All rights reserved.

CONCLUSIONS

• Best compressor choice depends on:

– Plant or site parameters

– Project parameters

– Process parameters

– Machinery parameters

Page 62: Selecting a reciprocating or centifugal compressor

© 2012 Valerus. Confidential and proprietary. All rights reserved.

CONCLUSIONS

Gas Turbine driven Centrifugal compressors are best when:

• Large horsepower is required

• Waste heat is required

• Limited range of process conditions

• Minimal foundation is required

• Light weight is desired

• Low fuel gas cost

• Long lead time is possible

Page 63: Selecting a reciprocating or centifugal compressor

© 2012 Valerus. Confidential and proprietary. All rights reserved.

CONCLUSIONS

Separable compressors are best when:

• High fuel cost

• No waste heat required

• Minimum initial cost required

• 6000 kw or less increments required

• Medium project life is required

• Relocation or conversion may be required

• Minimum shipping/construction schedule

• Maximum operating flexibility