Processing of CO2 rich gas (SONG, Nov. 11th 2014)

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


Adrian Finn extends grateful thanks to John O’Brien and to colleagues and management at Costain, Manchester, UK for their help

2


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


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


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


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


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


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


Ryan Holmes for CO2/C2 Azeotrope

– /

9


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


Bulk Cryogenic Fractionation

GAS

DRYING

PRESSURE

REDUCTION

(Turbo-Expanders)

LIQUIDS

SEPARATION

LIQUID

FRACTIONATION

“Rich” High

Pressure

Gas from

CATS

Water


NTS or TPL pipeline

MIXED LIQUIDS

(NGLs)




• 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


Cryogenic Fractionation by Freezing

GAS

DRYING

PRESSURE

REDUCTION

(Turbo-Expanders)

LIQUIDS

SEPARATION

LIQUID

FRACTIONATION

“Rich” High

Pressure

Gas from

CATS

Water


NTS or TPL pipeline

MIXED LIQUIDS

(NGLs)




• 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


Cryogenic Fractionation by Freezing

GAS

DRYING

PRESSURE

REDUCTION

(Turbo-Expanders)

LIQUIDS

SEPARATION

LIQUID

FRACTIONATION

“Rich” High

Pressure

Gas from

CATS

Water


NTS or TPL pipeline

MIXED LIQUIDS

(NGLs)




CFZ™ Shute Creek pilot facility, Wyoming

13


Cryogenic Separation by Freezing

GAS

DRYING

PRESSURE

REDUCTION

(Turbo-Expanders)

LIQUIDS

SEPARATION

LIQUID

FRACTIONATION

“Rich” High

Pressure

Gas from

CATS

Water


NTS or TPL pipeline

MIXED LIQUIDS

(NGLs)




• CryoCell® - Single Stage Bulk Removal. Can produce pure carbon dioxide and hydrocarbon/carbon dioxide stream as dictated by VLS equilibrium

14


Cryogenic Fractionation - Summary

GAS

DRYING

PRESSURE

REDUCTION

(Turbo-Expanders)

LIQUIDS

SEPARATION

LIQUID

FRACTIONATION

“Rich” High

Pressure

Gas from

CATS

Water


NTS or TPL pipeline

MIXED LIQUIDS

(NGLs)




• 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


Carbon Dioxide Rich Gas

GAS

DRYING

PRESSURE

REDUCTION

(Turbo-Expanders)

LIQUIDS

SEPARATION

LIQUID

FRACTIONATION

“Rich” High

Pressure

Gas from

CATS

Water


NTS or TPL pipeline

MIXED LIQUIDS

(NGLs)




But it is likely these process technologies will be used elsewhere, rather than on naturally occurring gas fields……….

16


Carbon Dioxide EOR

GAS

DRYING

PRESSURE

REDUCTION

(Turbo-Expanders)

LIQUIDS

SEPARATION

LIQUID

FRACTIONATION

“Rich” High

Pressure

Gas from

CATS

Water


NTS or TPL pipeline

MIXED LIQUIDS

(NGLs)




• 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


Carbon Dioxide EOR

GAS

DRYING

PRESSURE

REDUCTION

(Turbo-Expanders)

LIQUIDS

SEPARATION

LIQUID

FRACTIONATION

“Rich” High

Pressure

Gas from

CATS

Water


NTS or TPL pipeline

MIXED LIQUIDS

(NGLs)




• 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


Carbon Dioxide EOR

GAS

DRYING

PRESSURE

REDUCTION

(Turbo-Expanders)

LIQUIDS

SEPARATION

LIQUID

FRACTIONATION

“Rich” High

Pressure

Gas from

CATS

Water


NTS or TPL pipeline

MIXED LIQUIDS

(NGLs)




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Cryogenic Fractionation for EOR

GAS

DRYING

PRESSURE

REDUCTION

(Turbo-Expanders)

LIQUIDS

SEPARATION

LIQUID

FRACTIONATION

“Rich” High

Pressure

Gas from

CATS

Water


NTS or TPL pipeline

MIXED LIQUIDS

(NGLs)




• 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


Ryan Holmes vs. CFZ™ – for EOR

• GAS

DRYING

PRESSURE

REDUCTION

(Turbo-Expanders)

“Rich” High

Pressure

Gas from

CATS

Water


NTS or TPL pipeline

MIXED LIQUIDS

(NGLs)




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


Four Column Ryan Holmes

• GAS

DRYING

PRESSURE

REDUCTION

(Turbo-Expanders)

LIQUIDS

SEPARATION

LIQUID

FRACTIONATION

“Rich” High

Pressure

Gas from

CATS

Water


NTS or TPL pipeline

MIXED LIQUIDS

(NGLs)




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


Process Improvement Challenges

• GAS

DRYING

PRESSURE

REDUCTION

(Turbo-Expanders)

LIQUIDS

SEPARATION

LIQUID

FRACTIONATION

“Rich” High

Pressure

Gas from

CATS

Water


NTS or TPL pipeline

MIXED LIQUIDS

(NGLs)




• 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


Pure Carbon Dioxide Product

• GAS

DRYING

PRESSURE

REDUCTION

(Turbo-Expanders)

LIQUIDS

SEPARATION

LIQUID

FRACTIONATION

“Rich” High

Pressure

Gas from

CATS

Water


NTS or TPL pipeline

MIXED LIQUIDS

(NGLs)




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


C4+

Inlet Gas

Sulfur

NGL (C2 – C4)

Sales gas or fuel (C1) 3.5 MPa


Propane Recovery – Ethane in CO2

• GAS

DRYING

PRESSURE

REDUCTION

(Turbo-Expanders)

LIQUIDS

SEPARATION

LIQUID

FRACTIONATION

“Rich” High

Pressure

Gas from

CATS

Water


NTS or TPL pipeline

MIXED LIQUIDS

(NGLs)




25

Pro

pan

e R

eco

very

CO

2 R

eco

very

CFZ

Compression

Dehydration

Chilling

Compression15-30%

CO2


C3+

Inlet Gas

Sales gas or fuel (C1)

Selective H2S Removal

Sulfur


Lower Quality Gas (Power Generation)

• GAS

DRYING

PRESSURE

REDUCTION

(Turbo-Expanders)

LIQUIDS

SEPARATION

LIQUID

FRACTIONATION

“Rich” High

Pressure

Gas from

CATS

Water


NTS or TPL pipeline

MIXED LIQUIDS

(NGLs)




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• GAS

DRYING

PRESSURE

REDUCTION

(Turbo-Expanders)

LIQUIDS

SEPARATION

LIQUID

FRACTIONATION

“Rich” High

Pressure

Gas from

CATS

Water


NTS or TPL pipeline

MIXED LIQUIDS

(NGLs)




Pro

pan

e R

eco

very

CO

2 R

eco

very

Compression

Dehydration

Chilling

Compression 15-30% CO2


C3+

Inlet Gas

Fuel to gas turbines

(3.5 MPa)

H2S Removal

Sulfur


Process Options - Summary

• GAS

DRYING

PRESSURE

REDUCTION

(Turbo-Expanders)

LIQUIDS

SEPARATION

LIQUID

FRACTIONATION

“Rich” High

Pressure

Gas from

CATS

Water


NTS or TPL pipeline

MIXED LIQUIDS

(NGLs)


• 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 ?

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Conclusion

• GAS

DRYING

PRESSURE

REDUCTION

(Turbo-Expanders)

LIQUIDS

SEPARATION

LIQUID

FRACTIONATION

“Rich” High

Pressure

Gas from

CATS

Water


NTS or TPL pipeline

MIXED LIQUIDS

(NGLs)




• 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

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Conclusion

• GAS

DRYING

PRESSURE

REDUCTION

(Turbo-Expanders)

LIQUID

FRACTIONATION

“Rich” High

Pressure

Gas from

CATS

Water


NTS or TPL pipeline

MIXED LIQUIDS

(NGLs)




Thank You

Any Questions ?

Adrian Finn, Process Technology Manager

[email protected]

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Processing of CO2 rich gas (SONG, Nov. 11th 2014)

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Transcript of Processing of CO2 rich gas (SONG, Nov. 11th 2014)