two-phase expander – potential for reduced power ... engineering the 2nd international conference...

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2nd International Conference on Small Scale LNG in Europe

Bergen, Norway 22nd -24th May 2007

Eginhard Berger and Manfred Boelt: The Linde Group -Linde Engineering, Germany Dr. Hans Kimmel, Ebara, USA

Linde Engineering

The 2nd International Conference onSmall Scale LNG in Europe

Two-Phase Expander – Potential for Reduced Power Requirements in LNG Production Plants

Eginhard Berger, Manfred Boelt: The Linde Group -Linde Engineering, GermanyDr. Hans Kimmel, Ebara, USA

2 Berger/GVP/8.05.07/GVPLinde AG Linde Engineering Division

Linde Engineering

Two-Phase Expanders – a Large Potential for Reduced Power Requirement in LNG Production Plants

TPE (Two-Phase Expander) – Potential for Reduced Power Requirements in LNG Production Plants

Content:Basis of Comparison OptionsCurrent State of the Art and Development in Fluid Expansion for RefrigerationExpansion Options for the Linde Single Mixed Refrigerant CycleThermophysical Illustration of the LNG End Flash OptionsHeat – Temperature Diagrams (Pinch Analysis) of the LNG Process OptionsTPE (Two-Phase Expander) TechnologyEconomic Comparison of the Options


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Comparison Options:

JTE (Joule-Thomson Expansion)

HE + JTE(Hydraulic Expander) + (Joule-Thomson Expansion)

TPE (Two-Phase Expander)

LNG Process Comparison Basis:LiMuM(Linde Multi Stage Mixed Refrigerant) LNG ProcessTypical Natural Gas CompositionFeed Gas: Pressure 60 bar, Temperature 30 °C


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G

Technology Status:

JTE (Joule-Thomson Expansion)Generally used in most of the existing LNG plants for refrigeration

HE + JTE(Hydraulic Expander) + (Joule-Thomson Expansion)

Currently used in large LNG baseloadplants

TPE (Two-Phase Expander)Currently used in a small LNG plant, Combination of Hydraulic and Gas Expander

G


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M

Natural Gas

LNG

FuelGas

12

Simplified Process SketchLiMuM (Linde Multi Stage Mixed Refrigerant) LNG Process

Mixed Refrigerant Cycle


M

Precooling Cycle JTE Valve

Subcooling Cycle JTE Valve

LNG JTE Valve


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M

Natural Gas

LNG

FuelGas

1a

2



HE (Hydraulic Expander) +JTE (Joule-Thomson Expansion)

1

G

G

G

M

Precooling Cycle Expander+JTE

Subcooling Cycle Expander +JTE

LNG Expander +JTE


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M

Natural Gas

LNG

FuelGas

2




1G G

G

M

Precooling Cycle Expander

Subcooling Cycle Expander

LNG Expander


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Pressure - Temperature Diagram

0

10

20

30

40

50

60

110 120 130 140 150 160 170 180 190 200 210

Temperature K

P B

AR



HE (Hydraulic Expander)

Two-Phase Envelopeof a Typical Natural Gas

All Liquid

All Gas

Comparison of LNG End Flash


1

2

1a

Expansion Entry

Expansion Outlet


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Pressure - Temperature Diagram Section

0

10

20

30

40

50

60

111.8 112.8 113.8 114.8 115.8 116.8 117.8 118.8 119.8 120.8 121.8 122.8

Temperature K

P B

AR





All Liquid


Comparison of LNG End Flash

1

2

1a

Expansion Entry

Expansion Outlet


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Pressure - Enthalpy Diagram

0

10

20

30

40

50

60

-16000 -15000 -14000 -13000 -12000 -11000 -10000 -9000 -8000 -7000 -6000 -5000 -4000Enthalpy J/mol

Pres

sure

bar




All Liquid

All Gas

Comparison of LNG End Flash Section



1

2

1a

Expansion Outlet

Expansion Entry


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Pressure - Enthalpy Diagram

0

10

20

30

40

50

60

-14700 -14680 -14660 -14640 -14620 -14600 -14580 -14560 -14540 -14520 -14500 -14480 -14460 -14440Enthalpy J/mol

Pres

sure

bar




All Liquid

All Gas




1

2

1a

Expansion Entry

Expansion Outlet


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Temperature - Specific Entropy Diagram

110

120

130

140

150

160

170

180

190

200

210

80 90 100

110

120

130

140

150

160

170

Entropy J/mol.K

Tem

pera

ture

K




HE (Hydraulic Expander) +JTE (Joule-Thomson Expansion)


All Liquid All Gas

1

2 Expansion Outlet

Expansion Entry


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Temperature - Specific Entropy Diagram Section

111,8

112,8

113,8

114,8

115,8

116,8

117,8

118,8

119,8

120,8

121,8

122,8

85,8

86,0

86,2

86,4

86,6

86,8

87,0

87,2

87,4

87,6

87,8

88,0

Entropy J/mol.K

Tem

pera

ture

K






All Liquid HE (Hydraulic Expander)

1

2

1a

Expansion Outlet

Expansion Entry


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HEAT EXCHANGER : Q / TPROFILE FOR UNIT : E01 in LIMU25/CO01

Date/Time : 08.01.07 11:36:30

117 137 157 177 197 217 237 257 277 297 3170

0.75

1.50

2.25

3.00

3.75

4.50

5.25

6.00

6.75

T OF HEAT EXCHANGER (K)

ENTH

ALP

Y(S

UM

) OF

HEA

T EX

CH

AN

GER

(MW

)

hot sum curve cold sum curve


HEAT EXCHANGER : Q / TPROFILE FOR UNIT : E01 in LIMU32/CO01

Date/Time : 08.01.07 11:33:22

118 138 158 178 198 218 238 258 278 298 3180

0.75

1.50

2.25

3.00

3.75

4.50

5.25

6.00

6.75


ENTH

ALP

Y(S

UM

) OF

HEA

T EX

CH

AN

GER

(MW

)


HE + JTE (Hydraulic Expander +

(Joule-Thompson Expansion)

HEAT EXCHANGER : Q / TPROFILE FOR UNIT : E01 in LIMU19/CS01

Date/Time : 08.01.07 11:28:41

116 136 156 176 196 216 236 256 276 296 3160

0.75

1.50

2.25

3.00

3.75

4.50

5.25

6.00

6.75


ENTH

ALP

Y(S

UM

) OF

HEA

T EX

CH

AN

GER

(MW

)


JTE (Joule-Thompson Expansion)

Heat – Temperature Diagrams

(Pinch Analysis)


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Result of theoretical calculations based on 80% efficiency for each expander(both for HE and for TPE)

JTE

(Joule-Thomson Expansion)

HE + JTE

(Hydraulic Expander)

+ (Joule-Thomson Expansion)

TPE

(Two-Phase

Expander)

Specicif power requirementkWh/Nm3

kWh/Nm3 0.281 0.253 0.243

Relative specific powerrequirement

% 100 90.04 86.48

Relative LNG production with a given power installation

+ expander / generator sets% 100 111.3 115.6


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Example of a 100 000 Nm3/h LNG plant range

JTE HE+JTE TPE

LNG Production Nm3/h 100000 111273 115591

Basic power installed (eg all electric drive) MW 28.15 28.15 28.15

Additional power by expanders

Precooling expander MW 0.26 0.32

Subcooling expander MW 0.27 0.40

LNG expander MW 0.19 0.30

Total installed power MW 28.15 28.87 29.17


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Theoretical economic assessment (table):

JTE HE+JTE TPELNG Production Nm3/h 100000 111273 115591

Fuel gas consumption Nm3/h 10750 11080 11208

Annual feed gas cost Mill. €/a 17.72 19.58 20.29

Annual LNG sales revenues Mill. €/a 119.85 133.36 138.54

Power incl. expanders MW 28.15 28.87 29.17

Investment cost: Power Mill. € 72 77.75 80.18

Process Mill. € 108 116.4 119.5

Total Mill. € 180 194.1 199.7

Annual operating cost (10% of investment cost) Mill €/a 18 19.4 20.0

Annual profit before tax Mill €/a 84.13 94.37 98.28

Pay-out time (Investment cost / annual profit before tax) a 2.14 2.06 2.03Relaitve pay-out time % 100 96 95

Specific feed/fuel gas price: 0.02 €/Nm3 (ab. 0.53 €/MMBTU), LNG sales price: 0.15 €/Nm3 (about 4 €/MMBTU), Operation: 8000 h/a


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Theoretical economic assessment (bar chart):

Rough Pay-out TimeInvestment Cost / Annual Profit before Tax

2.14 2.06 2.03

100% 96% 95%

0.00

0.50

1.00

1.50

2.00

2.50

JTE HE+JTE TPEOptions

Year

s


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EBARA Hydraulic Expanders in the Snoehvit LNG Plant in Hammerfest


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Installation of Two-Phase LNG Expander at KRIO Polish Oil & Gas, Odolanow, Poland

January 20003


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Two-Phase ExpanderFull turbine section with nozzle

and

Runner iso transparent


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Two-Phase ExpanderExducer with cut

and

translucent shroud


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Two-Phase ExpanderHydraulic top

and

iso view


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Conclusion:Efficiency Improvement in LNG Plants is Mandatory forEnvironmental and Economical Reasons

TPE is a Contribution to this Requirement

TPE Provides Sensible Reduction in Specific Power Requirements in LNG Plants

TPE: Hydraulic and Gas Expansion: a Combined Unit as a Logic Consequence of the Current Practice

TPE is Applicable in Small LNG Baseload Plants

TPE will become Beneficial in Particular with Large Capacity LNG Plants (Economy of Scale)

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Thank youfor your attention

Linde Process Concepts

two-phase expander – potential for reduced power ... engineering the 2nd international conference...

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