Simultaneous Production of LNG and NGL

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Simultaneous Productionof LNG and NGL

• Philip HAGYARD
• Henri PARADOWSKI
• Dominique GADELLE

Pascale MORIN Jean-Claude GARCEL
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• Why NGL with LNG is of increasing interest
• NGL recovery processes
• Case study Cryomax process
• ? 0 - 65 ethane recovery
• ? Three configurations in LNG train
• Operability and reliability considerations

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NGL recovery in LNG plants
Next step
Existing LNG plants
100
Sometimes
C4
90 - 95
Sometimes
C3
30 - 50
Once
C2
Turbo-Expander
Scrub column
Scheme
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Ethane

• New markets require lean revaporised NG
• UK Wobbe Index 51.4 MJ/Sm3 (max)
• 50.8 MJ/Sm3 in Qatar
• Met with 36 ethane extraction
• Ethylene from ethane in Qatar
• Qatar 2.5 Mtpa in 2008
• UK 2.8 Mtpa (all feed stocks)
• France 3.4 Mtpa (all feed stocks)

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• Why NGL with LNG is of increasing interest
• NGL recovery processes
• Case study Cryomax process
• ? 0 - 65 ethane recovery
• ? Three configurations in LNG train
• Operability and reliability considerations

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NGL recovery processes

• Efficient ethane and propane plus extraction
• Flexibility in ethane recovery
• Good selectivity - minimal methane in NGL
• Entrainment tolerant no heavy ends, ever
• Resistance to equipment failure
• Lean gas at high pressure to favour liquefaction

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Conventional scrub column
C3R
NG 54 bar -35C
NG 55 bar -16C
NGL
LNG
C3R
SCRUB COLUMN
LIQUEFACTION MCHE
REFLUX
PRECOOLING
LEAN GAS
C3R
MR
NGL
DRY NG
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Scrub column (high recovery)
MCHE
NG 52 bar -65C
NG 55 bar -35C
LNG
NGL
REFLUX
LIQUEFACTION MCHE
PRECOOLING
SCRUB COLUMN
OVERHEAD
LEAN GAS
C3R
MR
NGL
DRY NG
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Cryomax
LNG
LIQUEFACTION MCHE
PRECOOLING
CRYOMAX DUAL COLUMN NGL RECOVERY
LEAN GAS
C3R
MR
NGL
DRY NG
10
Cryomax - LNG
LEAN GAS TO MCHE
PRECOOLED GAS
36 bar -80C
29 bar
DC1
RT
Recovery Tower Reflux
NGL
Demethaniser Reflux
US Patent 5,291,736
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• Why NGL with LNG is of increasing interest
• NGL recovery processes
• Case study Cryomax process
• ? 0 - 65 ethane recovery
• ? Three configurations in LNG train
• Operability and reliability considerations

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Cryomax Case Study

• Qatar North Field gas climate
• APCI C3/MCR process
• High LNG capacity (approximately 5 Mtpa)
• High natural gas pressures
• Two GE Frame 7 gas turbines
• MCHE outlet temperature 148C
• Hydraulic turbines for MCR and LNG
• Four ethane extraction rates (0-65) in three
  configurations

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Cryomax Unit Location

• Front End
• Warm natural gas feed
• No propane refrigeration
• Driven by lean gas compression
• Inlet Outlet (P T)

NG
NGL
NRU OFF GAS
FRONT END
NGL RECOVERY
LEAN GAS COMPRESSION
C3 PRECOOLING
NG LIQUEFACTION
NITROGEN REMOVAL
LNG

• Straddle
• Pre-cooled feed
• Inlet Outlet (P T)

NGL
NG
STRADDLE
NRU OFF GAS
NGL RECOVERY
LEAN GAS COMPRESSION
C3 PRECOOLING
NG LIQUEFACTION
NITROGEN REMOVAL

• Mid train
• Pre-cooled feed
• P2 lt P1
• Simpler
• Less power
• Less capacity

LNG
NG
NGL
NRU OFF GAS
MID TRAIN
C3 PRECOOLING
NITROGEN REMOVAL
NGL RECOVERY
NG LIQUEFACTION
LNG
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• Why NGL with LNG is of increasing interest
• NGL recovery processes
• Case study Cryomax process
• ? 0 - 65 ethane recovery
• ? Three configurations in LNG train
• Operability and reliability considerations

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NGL recovery rates
65
36
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1
Ethane
97.7
94.5
95.8
99.0
Propane
100
100
100
100
Butane
1019.0
1033.8
1042.0
1046.6
HHV Btu/scf
50.5
50.8
51.0
51.1
Wobbe MJ/Sm3
In LNG tanks in Qatar
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Specific power
Target C2 Recovery
Front end
Straddle
Mid-train
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• Why NGL with LNG is of increasing interest
• NGL recovery processes
• Case study Cryomax process
• ? 0 - 65 ethane recovery
• ? Three configurations in LNG train
• Operability and reliability considerations

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Straddle - Lean gas compressor failure

• Same as mid-train scheme
• LNG quality unchanged
• 10 to 15 reductionin throughput

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Straddle - Joule-Thomson Mode

• C3 precooling lean gas compressor OK
• Specifications OK except Wobbe
• 5-10 reductionin throughput

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Straddle - Joule-Thomson Mode

• C3 precooling lean gas compressor OK
• Specifications OK except Wobbe
• 5-10 reductionin throughput

Expander
JT mode
-
5.4
Expander power MW
1
36
Ethane recovery
76
93
Propane recovery
51.2
50.8
Wobbe Index MJ/Sm3
0.287
0.267
Sp consumption MW.h/t
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Conclusions

• Ethane and C3/C4 LPG extraction in Qatar meets
  lean gas specifications directly
• The Cryomax process can be adapted to a wide
  range of ethane recovery requirements
• Process efficiency insensitive to extraction rate
  or location
• Cryomax Straddle Efficient and reliable
• New or existing trains

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Technip and Totalthank you for your attention