processing of co2 rich gas (song, nov. 11th 2014)
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COSTAIN NATURAL RESOURCES DIVISION
Processing of Carbon Dioxide Rich Gas
Adrian Finn & John V O’Brien (EOR Energy)
I Chem E SONG, London 11th November 2014
1
COSTAIN NATURAL RESOURCES DIVISION
Adrian Finn extends grateful thanks to John O’Brien and to colleagues and management at Costain, Manchester, UK for their help
2
COSTAIN NATURAL RESOURCES DIVISION
Introduction
– Increasing worldwide demand for natural gas - clean burning fuel
– Exploit indigenous high (> 10 % ?) carbon dioxide content gas ? In lieu of importing LNG (even coal !)
– Climate change – must sequestrate carbon dioxide. But this adds to plant cost and diminishes project viability
– So can carbon dioxide rich gas be processed economically ?
– And if so, how ?
3
COSTAIN NATURAL RESOURCES DIVISION
Process Technologies
– Solvent – chemical or physical
– Semi-permeable membranes
– All are costly (even if venting to the air)
– Physical solvent is better than chemical solvent at high partial pressure but hydrocarbon pick-up and loss
– Membrane is simple but has high machinery cost
– For disposal want dry, high pressure (> 140 bar) pure liquid carbon dioxide. None of the above meet any of these requirements .
4
COSTAIN NATURAL RESOURCES DIVISION
Cryogenic Fractionation
Higher the carbon dioxide content the more efficient it is……
(Hence carbon capture for oxyfuel and precombustion power plants)
Reduce power consumption, smaller machinery, lower cost
5
COSTAIN NATURAL RESOURCES DIVISION
Cryogenic Fractionation
Benefits of Cryogenic Fractionation that Reduce Gas Processing Cost
• High Methane/Carbon Dioxide Relative Volatility
• High Product Recoveries
• High Carbon Dioxide Purity (99.999% as required for “food grade”)
• High Pressure Carbon Dioxide (Liquid) to boost to > 140 bar
Is there a “catch” ?
6
COSTAIN NATURAL RESOURCES DIVISION
Sales Gas Purity
• Cannot achieve sales gas specification (4 mol. % or less)
• Methane Pc = 46 bara, must fractionate at < 46 bara, typically 36 bara
• Upper part of cryogenic demethaniser then < - 60 °C
• So carbon dioxide freezes !
• So must allow carbon dioxide in overheads to be > 15 %
• Pc is increased compared to methane alone, so can process at 40 bara
• But this is a severe restriction to cryogenic processing !
7
COSTAIN NATURAL RESOURCES DIVISION
Ryan Holmes Demethaniser
• Add hydrocarbon solvent at top of the demethaniser
• Increases the solubility of carbon dioxide
• Increases the operating temperature
• Increases the critical locus (Pc) so higher α, easier separation
• Now obtain pure methane overheads (sales gas quality)
• But the solvent contaminates the carbon dioxide bottoms, so more fractionation, refrigeration, heat, ….…..& cost
8
COSTAIN NATURAL RESOURCES DIVISION
Ryan Holmes Fractionation
GAS
DRYING
PRESSURE
REDUCTION
(Turbo-Expanders)
LIQUIDS
SEPARATION
LIQUID
FRACTIONATION
“Rich” High
Pressure
Gas from
CATS
Water
“Lean” Gas Product to
NTS or TPL pipeline
MIXED LIQUIDS
(NGLs)
Propane Butane Condensate
Liquid Products exported
by pipeline to SABIC
• Used on about a dozen plants in 1980s (USA)
• Clearly some complexity !
• A potential technology candidate ?
• What are the options ?
10
COSTAIN NATURAL RESOURCES DIVISION
Bulk Cryogenic Fractionation
GAS
DRYING
PRESSURE
REDUCTION
(Turbo-Expanders)
LIQUIDS
SEPARATION
LIQUID
FRACTIONATION
“Rich” High
Pressure
Gas from
CATS
Water
“Lean” Gas Product to
NTS or TPL pipeline
MIXED LIQUIDS
(NGLs)
Propane Butane Condensate
Liquid Products exported
by pipeline to SABIC
• Century gas plant, West Texas – 65% carbon dioxide content
• Bulk Fractionation to 21 % carbon dioxide
• Then Selexol™ to < 4% carbon dioxide
• Good use of two technologies
• But of course the low pressure gaseous carbon dioxide means high compression power and high cost for > 140 bar
11
COSTAIN NATURAL RESOURCES DIVISION
Cryogenic Fractionation by Freezing
GAS
DRYING
PRESSURE
REDUCTION
(Turbo-Expanders)
LIQUIDS
SEPARATION
LIQUID
FRACTIONATION
“Rich” High
Pressure
Gas from
CATS
Water
“Lean” Gas Product to
NTS or TPL pipeline
MIXED LIQUIDS
(NGLs)
Propane Butane Condensate
Liquid Products exported
by pipeline to SABIC
• ExxonMobil CFZ™
• Capital and Operating Cost Savings ? Needs refrigeration so main cost saving on process simplicity ?
• Extensive Development
• As low as 8 % carbon dioxide ?
• Must remove NGL (upstream)
12
COSTAIN NATURAL RESOURCES DIVISION
Cryogenic Fractionation by Freezing
GAS
DRYING
PRESSURE
REDUCTION
(Turbo-Expanders)
LIQUIDS
SEPARATION
LIQUID
FRACTIONATION
“Rich” High
Pressure
Gas from
CATS
Water
“Lean” Gas Product to
NTS or TPL pipeline
MIXED LIQUIDS
(NGLs)
Propane Butane Condensate
Liquid Products exported
by pipeline to SABIC
CFZ™ Shute Creek pilot facility, Wyoming
13
COSTAIN NATURAL RESOURCES DIVISION
Cryogenic Separation by Freezing
GAS
DRYING
PRESSURE
REDUCTION
(Turbo-Expanders)
LIQUIDS
SEPARATION
LIQUID
FRACTIONATION
“Rich” High
Pressure
Gas from
CATS
Water
“Lean” Gas Product to
NTS or TPL pipeline
MIXED LIQUIDS
(NGLs)
Propane Butane Condensate
Liquid Products exported
by pipeline to SABIC
• CryoCell® - Single Stage Bulk Removal. Can produce pure carbon dioxide and hydrocarbon/carbon dioxide stream as dictated by VLS equilibrium
14
COSTAIN NATURAL RESOURCES DIVISION
Cryogenic Fractionation - Summary
GAS
DRYING
PRESSURE
REDUCTION
(Turbo-Expanders)
LIQUIDS
SEPARATION
LIQUID
FRACTIONATION
“Rich” High
Pressure
Gas from
CATS
Water
“Lean” Gas Product to
NTS or TPL pipeline
MIXED LIQUIDS
(NGLs)
Propane Butane Condensate
Liquid Products exported
by pipeline to SABIC
• Ryan Holmes and CFZ™ for > 10 % carbon dioxide content natural gas
• CFZ™ has less processing and simpler, but not yet proven commercially
• CFZ™ requires more complex refrigeration (ethylene)
• CFZ™ needs upstream processing to remove NGL
• Consider both processes, especially for carbon dioxide disposal.
• No short cuts – evaluate by process/plant design & cost estimates
15
COSTAIN NATURAL RESOURCES DIVISION
Carbon Dioxide Rich Gas
GAS
DRYING
PRESSURE
REDUCTION
(Turbo-Expanders)
LIQUIDS
SEPARATION
LIQUID
FRACTIONATION
“Rich” High
Pressure
Gas from
CATS
Water
“Lean” Gas Product to
NTS or TPL pipeline
MIXED LIQUIDS
(NGLs)
Propane Butane Condensate
Liquid Products exported
by pipeline to SABIC
But it is likely these process technologies will be used elsewhere, rather than on naturally occurring gas fields……….
16
COSTAIN NATURAL RESOURCES DIVISION
Carbon Dioxide EOR
GAS
DRYING
PRESSURE
REDUCTION
(Turbo-Expanders)
LIQUIDS
SEPARATION
LIQUID
FRACTIONATION
“Rich” High
Pressure
Gas from
CATS
Water
“Lean” Gas Product to
NTS or TPL pipeline
MIXED LIQUIDS
(NGLs)
Propane Butane Condensate
Liquid Products exported
by pipeline to SABIC
• Practiced extensively in US (Permian Basin) with naturally occurring carbon dioxide
• Miscible flood can increase oil recovery by up to 70%
• 300,000 bopd (about 6% of US production) via 136 projects – that use 68 million tonnes per year of carbon dioxide
• The Century gas plant could recover 500 million barrels
• Gasification plant carbon capture for EOR at Midale, Weyburn, Canada More such projects are proceeding
17
COSTAIN NATURAL RESOURCES DIVISION
Carbon Dioxide EOR
GAS
DRYING
PRESSURE
REDUCTION
(Turbo-Expanders)
LIQUIDS
SEPARATION
LIQUID
FRACTIONATION
“Rich” High
Pressure
Gas from
CATS
Water
“Lean” Gas Product to
NTS or TPL pipeline
MIXED LIQUIDS
(NGLs)
Propane Butane Condensate
Liquid Products exported
by pipeline to SABIC
• Increasing Middle East interest and research – ADNOC, Kuwait
• Carbon dioxide could be dominant EOR technique in Middle East within a decade
• Pemex considering for EOR rather than nitrogen
• Maybe 3 billion barrels are recoverable from the North Sea
• Oil recovery & lower carbon dioxide emissions. Declining reserves & high production costs justify consideration
18
COSTAIN NATURAL RESOURCES DIVISION
Carbon Dioxide EOR
GAS
DRYING
PRESSURE
REDUCTION
(Turbo-Expanders)
LIQUIDS
SEPARATION
LIQUID
FRACTIONATION
“Rich” High
Pressure
Gas from
CATS
Water
“Lean” Gas Product to
NTS or TPL pipeline
MIXED LIQUIDS
(NGLs)
Propane Butane Condensate
Liquid Products exported
by pipeline to SABIC
19
COSTAIN NATURAL RESOURCES DIVISION
Cryogenic Fractionation for EOR
GAS
DRYING
PRESSURE
REDUCTION
(Turbo-Expanders)
LIQUIDS
SEPARATION
LIQUID
FRACTIONATION
“Rich” High
Pressure
Gas from
CATS
Water
“Lean” Gas Product to
NTS or TPL pipeline
MIXED LIQUIDS
(NGLs)
Propane Butane Condensate
Liquid Products exported
by pipeline to SABIC
• Injected carbon dioxide “breaks through” with oil and gas
• Towards “end of life” gas is up to 90 % carbon dioxide
• To be removed for recycle (as with NGL that also comes), for sales gas
• Require high pressure pure liquid carbon dioxide (for MMP)
• Thus Cryogenic Fractionation is the “Technology of Choice”
20
COSTAIN NATURAL RESOURCES DIVISION
Ryan Holmes vs. CFZ™ – for EOR
• GAS
DRYING
PRESSURE
REDUCTION
(Turbo-Expanders)
“Rich” High
Pressure
Gas from
CATS
Water
“Lean” Gas Product to
NTS or TPL pipeline
MIXED LIQUIDS
(NGLs)
Propane Butane Condensate
Liquid Products exported
by pipeline to SABIC
21
• Proven Technology
• Handles NGL rich feed
• No Hydrogen Sulphide in the CO2
• Conventional Equipment
• Similar Refrigeration Duties (though
CFZ™ requires < -40°C
• But More Process Equipment &
More Operating Variables
COSTAIN NATURAL RESOURCES DIVISION
Four Column Ryan Holmes
• GAS
DRYING
PRESSURE
REDUCTION
(Turbo-Expanders)
LIQUIDS
SEPARATION
LIQUID
FRACTIONATION
“Rich” High
Pressure
Gas from
CATS
Water
“Lean” Gas Product to
NTS or TPL pipeline
MIXED LIQUIDS
(NGLs)
Propane Butane Condensate
Liquid Products exported
by pipeline to SABIC
22
H2S
& E
than
e R
eco
very
CO
2 R
eco
very
De
met
han
ize
r
Ad
diti
ve R
eco
very
Compression
Dehydration
Amine, Claus
Chilling
Compression15-30%
CO2
NGL + H2S
Additive Recycle
CO2 to injection(14 MPa)
C4+
Inlet Gas (70 kPa.g)
Sulfur
NGL (C2 – C4)
Sales gas or fuel (C1) 3.5 MPa
COSTAIN NATURAL RESOURCES DIVISION
Process Improvement Challenges
• GAS
DRYING
PRESSURE
REDUCTION
(Turbo-Expanders)
LIQUIDS
SEPARATION
LIQUID
FRACTIONATION
“Rich” High
Pressure
Gas from
CATS
Water
“Lean” Gas Product to
NTS or TPL pipeline
MIXED LIQUIDS
(NGLs)
Propane Butane Condensate
Liquid Products exported
by pipeline to SABIC
• Process design for increasing carbon dioxide and NGL
• Assess across early, peak and later years
• Also consider declining feed gas pressure and flowrate
• Process integration (to reduce energy consumption) is not reliable – not easy to ensure robust design/performance
• Improve ? Upstream membrane ? OK but low pressure carbon dioxide
• So are there any technology advances to reduce processing cost ?
23
COSTAIN NATURAL RESOURCES DIVISION
Pure Carbon Dioxide Product
• GAS
DRYING
PRESSURE
REDUCTION
(Turbo-Expanders)
LIQUIDS
SEPARATION
LIQUID
FRACTIONATION
“Rich” High
Pressure
Gas from
CATS
Water
“Lean” Gas Product to
NTS or TPL pipeline
MIXED LIQUIDS
(NGLs)
Propane Butane Condensate
Liquid Products exported
by pipeline to SABIC
24
H2S
& E
than
e R
eco
very
CO
2 R
eco
very
CFZ
Ad
diti
ve R
eco
very
Compression
Dehydration
Amine, Claus
Chilling
Compression15-30%
CO2
NGL + H2S
Additive Recycle
CO2 to injection(14 MPa)
C4+
Inlet Gas
Sulfur
NGL (C2 – C4)
Sales gas or fuel (C1) 3.5 MPa
COSTAIN NATURAL RESOURCES DIVISION
Propane Recovery – Ethane in CO2
• GAS
DRYING
PRESSURE
REDUCTION
(Turbo-Expanders)
LIQUIDS
SEPARATION
LIQUID
FRACTIONATION
“Rich” High
Pressure
Gas from
CATS
Water
“Lean” Gas Product to
NTS or TPL pipeline
MIXED LIQUIDS
(NGLs)
Propane Butane Condensate
Liquid Products exported
by pipeline to SABIC
25
Pro
pan
e R
eco
very
CO
2 R
eco
very
CFZ
Compression
Dehydration
Chilling
Compression15-30%
CO2
CO2 to injection(14 MPa)
C3+
Inlet Gas
Sales gas or fuel (C1)
Selective H2S Removal
Sulfur
COSTAIN NATURAL RESOURCES DIVISION
Lower Quality Gas (Power Generation)
• GAS
DRYING
PRESSURE
REDUCTION
(Turbo-Expanders)
LIQUIDS
SEPARATION
LIQUID
FRACTIONATION
“Rich” High
Pressure
Gas from
CATS
Water
“Lean” Gas Product to
NTS or TPL pipeline
MIXED LIQUIDS
(NGLs)
Propane Butane Condensate
Liquid Products exported
by pipeline to SABIC
26
• GAS
DRYING
PRESSURE
REDUCTION
(Turbo-Expanders)
LIQUIDS
SEPARATION
LIQUID
FRACTIONATION
“Rich” High
Pressure
Gas from
CATS
Water
“Lean” Gas Product to
NTS or TPL pipeline
MIXED LIQUIDS
(NGLs)
Propane Butane Condensate
Liquid Products exported
by pipeline to SABIC
Pro
pan
e R
eco
very
CO
2 R
eco
very
Compression
Dehydration
Chilling
Compression 15-30% CO2
CO2 to injection(14 MPa)
C3+
Inlet Gas
Fuel to gas turbines
(3.5 MPa)
H2S Removal
Sulfur
COSTAIN NATURAL RESOURCES DIVISION
Process Options - Summary
• GAS
DRYING
PRESSURE
REDUCTION
(Turbo-Expanders)
LIQUIDS
SEPARATION
LIQUID
FRACTIONATION
“Rich” High
Pressure
Gas from
CATS
Water
“Lean” Gas Product to
NTS or TPL pipeline
MIXED LIQUIDS
(NGLs)
Propane Butane Condensate
• CFZ™ column could replace Ryan Holmes demethaniser. Simpler but refrigeration more complex. Is CFZ™ available to use ?
• If ethane is tolerable in carbon dioxide product, no need to remove, simpler process. But effect on miscibility and oil recovery ?
• If need pure carbon dioxide then Ryan Holmes optimal (unless very low NGL content gas, unlikely with EOR)
• If bulk remove carbon dioxide before CFZ™ then lower refrigeration cost, smaller CFZ™ column, more stable feed. But at cost of upstream “bulk” column. “Economies of scale” influence process choices ?
27
Propane Butane Condensate
COSTAIN NATURAL RESOURCES DIVISION
Conclusion
• GAS
DRYING
PRESSURE
REDUCTION
(Turbo-Expanders)
LIQUIDS
SEPARATION
LIQUID
FRACTIONATION
“Rich” High
Pressure
Gas from
CATS
Water
“Lean” Gas Product to
NTS or TPL pipeline
MIXED LIQUIDS
(NGLs)
Propane Butane Condensate
Liquid Products exported
by pipeline to SABIC
• Cryogenic Fractionation for carbon dioxide containing natural gas
• Gives pure high pressure carbon dioxide for potential storage
• Ryan Holmes and CFZ™ stand out
• EOR is gaining in popularity as oil fields deplete and reserves decline
• Ryan Holmes appropriate but high costs due to high recycle
• Process options with CFZ™ lower recycle and lower cost
• Carbon dioxide purity is key to process selection
• Process selection, evaluation & optimisation to reduce processing cost
• Carbon dioxide EOR - a key technology for 2020+, for both increased oil production and for carbon sequestration
28
COSTAIN NATURAL RESOURCES DIVISION
Conclusion
• GAS
DRYING
PRESSURE
REDUCTION
(Turbo-Expanders)
LIQUID
FRACTIONATION
“Rich” High
Pressure
Gas from
CATS
Water
“Lean” Gas Product to
NTS or TPL pipeline
MIXED LIQUIDS
(NGLs)
Propane Butane Condensate
Liquid Products exported
by pipeline to SABIC
Thank You
Any Questions ?
Adrian Finn, Process Technology Manager
adrian.finn@costain.com
29
Propane Butane Condensate
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