Oil & Gas Processing Plants
Design and Operation
Training Course
DGEP/SCR/ED/ECP - 24th March-4th April 2003
GAS SWEETENING PROCESSES
DGEP/SCR/ED/ECP - 24th March-4th April 2003
DGEP/SCR/ED/ECP 3
GAS SWEETENING
• SALES GAS SPECIFICATION- To meet the H2S content Specification
H2S Content < 4 ppm Vol.
- To increase THE GROSS CALORIFIC VALUE
CO2 Removal
• PROCESS CONSTRAINTS- CRYOGENIC PROCESSES (Ethane extraction, LNG Manufacture) CO2
Solidification at temperatures below - 70/80°C
• CRUDE SWEETENING USING STRIPPING GAS- To remove H2S From the Stripping Gas
DGEP/SCR/ED/ECP 4
GAS SWEETENING PROCESSES
PROCESSES DEPENDING ON CONTAMINANTS TO BE REMOVED :
• CO2 ONLY
• H2S ONLY
• CO2 & H2S SIMULTANEOUSLY
• SELECTIVE REMOVAL OF H2S
DGEP/SCR/ED/ECP 5
GAS SWEETENING PROCESSES
• CHEMICAL ABSORPTION
• PHYSICAL ABSORPTION
• PHYSICO- CHEMICAL ABSORPTION
• PHYSICAL ADSORPTION
• CRYOGENIC PROCESS (CO2 Removal only)
• MEMBRANES
• Direct Conversion To SULPHUR
DGEP/SCR/ED/ECP 6
• CHEMICAL ABSORPTION
DGEP/SCR/ED/ECP 7
CHEMICAL ABSORPTION
DGEP/SCR/ED/ECP 8
CHEMICAL ABSORPTION
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CHEMICAL ABSORPTION
DGEP/SCR/ED/ECP 10
CHEMICAL ABSORPTION
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CHEMICAL ABSORPTION
DGEP/SCR/ED/ECP 12
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DEA PROCESS
• ADVANTAGES :- No degradation by COS & CS2- Absorption of mercaptans- Good stability- low absorption of HC- No reclaimer- reduced vaporization losses- public
• DISADVANTAGES :- Higher circulation rate (lower activity)- Higher utility requirements- Oxydation- No selectivity between H2S & CO2
• UTILIZATION : H2S, CO2, COS, CS2, RSH (up to 20%)
• SPLIT FLOW
• SNEA-DEA : higher concentration
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MDEA PROCESS
DGEP/SCR/ED/ECP 15
MDEA PROCESS
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CHEMICAL ABSORPTION
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HOT CARBONATE PROCESS
• ADVANTAGES :- No degradation by COS & CS2- Good chemical stability- No reaction with air- low absorption of HC- No reclaimer- Low heat requirement (50% of corresponding amine unit)
• DISADVANTAGES :- Low reactivity with H2S- No mercaptans absorption- higher water content of treated gas- licensing fee
• UTILIZATION : HIGH CO2- if H2S in two steps :
K2CO3 + mol. Sieves
K2CO3 + AMINE
• SPLIT FLOW : solution cooling / two stages process / LO HEAT
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HOT CARBONATE PROCESS
DGEP/SCR/ED/ECP 19
HOT CARBONATE PROCESS
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• PHYSICAL ABSORPTION
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PHYSICAL ABSORPTION
• WATER WASH : partial treatment• SELEXOL PROCESS : NORTON (dimethyl ether of polyethylene glycol)
- up to 65% of CO2- light gas sweetening- regeneration by flash
• FLUOR SOLVENT : propylene carbonate
- up to 50% of CO2- Gas dehydration by as solvent and heat regeneration
• PURISOL : LURGI
- Selective process to remove H2S even in case of low H2S/CO2 ratio- Gas dehydration by add solvent and heat regeneration
• RECTISOL : LURGI - Refrigerated solution of MeOH (high selectivity for CO2)
• ESTASOLVAN : UHDE
- Recompression of flashed gas
• SEPASOLV-MPE : BASF
- Recoompression of flashed gas
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SELEXOL PROCESS
DGEP/SCR/ED/ECP 23
MORPHYSORB PROCESS
DGEP/SCR/ED/ECP 24
PHYSICAL ABSORPTION
DGEP/SCR/ED/ECP 25
AMINE PROCESS GUIDELINE
DGEP/SCR/ED/ECP 26
PHYSICO-CHEMICAL PROCESS
DGEP/SCR/ED/ECP 27
SULFINOL PROCESS
DGEP/SCR/ED/ECP 28
• CHEMICO-PHYSICAL ABSORPTION
DGEP/SCR/ED/ECP 29
SULIFINOL (SHELL)
DGEP/SCR/ED/ECP 30
SULFINOL (SHELL)
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HYBRISOL PROCESS
DGEP/SCR/ED/ECP 32
HYBRISOL PROCESS
DGEP/SCR/ED/ECP 33
• PHYSICAL ADSORPTION
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PHYSICAL ADSORPTION
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PHYSICAL ADSORPTION
DGEP/SCR/ED/ECP 36
CRYOGENIC PROCESS
DGEP/SCR/ED/ECP 37
CO2 REMOVAL BY CRYOGENICS
DGEP/SCR/ED/ECP 38
SPREX
DGEP/SCR/ED/ECP 39
• PERMEATION (Membranes)
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MEMBRANE PROCESS
• MEMBRANE TECHNOLOGY For bulk removal of CO2
DGEP/SCR/ED/ECP 41
LOW PRESSUREPERMEATE GAS
HIGH PRESSUREGAS MIXTURE RESIDUAL GAS
PERMEATE TUBERESIDUAL GAS
RESIDUAL GAS
HIGH PRESSURECHANNEL SPACER
PERMEATE CHANNEL SPACER
HIGH PRESSURE GAS MIXTURE
MEMBRANE/CLOTH COMPOSITE
HIGH PRESSURE GAS MIXTURE
Figure XI - B18 : SPIRAL WOUND ELEMENT CONSTRUCTION
DGEP/SCR/ED/ECP 42
CO2 RICH GAS
Seal Gasket
Epoxy coating
Aluminium TubeDiam. 3 to 4 cmHolesDiam. 5 to 7 mm
RESIDUE GAS
FibersBundleDiam. 4’’ and 9 1/2’’Length 1 m
FEED GAS
CO2 RICH GAS
(CYNARA)
Figure XI - B19 : HOLLOW FIBER MEMBRANE ELEMENT
DGEP/SCR/ED/ECP 43
FIBER MEMBRANE
DGEP/SCR/ED/ECP 44
FIBER MEMBRANE
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FIBER MEMBRANE
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TYPICAL ONE STAGE MEMBRANE PFD
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MEMBRANE PROCESS
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MEMBRANE PROCESS
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MEMBRANE PROCESS
DGEP/SCR/ED/ECP 50
MEMBRANE PROCESS
DGEP/SCR/ED/ECP 51
PROCESS COMPARISON
DIRECT CONVERSIONTO SULPHUR
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PROCESS COMPARISON
ABSORPTION :
H2S + 2 Fe3+(L) -------> 2 H+ + S° + 2 Fe2+(L)
REGENERATION :
1/2 O2 + H2O + 2 Fe2+(L) ------> 2 OH- + 2 Fe3+(L)
OVERALL :
H2S + 1/2 O2 -------> H2O + S°
DGEP/SCR/ED/ECP 53
SULFINT (IFP)
DGEP/SCR/ED/ECP 54
DIRECT CONVERSION TO SULPHUR
FIELD OF APPLICATIONLOW FLOWRATE• LOW PRESSURE (EXCEPT SULFINT FROM IFP)• LOW H2S CONTENT ( < 1000 ppm )
LICENSORS• US FILTER ( LO-CAT)• IFP with Le Gaz Intégral (SULFINT)• SHELL ( SULFEROX )
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PROCESS COMPARISON
GUIDE LINE FOR PROCESS SELECTION
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CHEMICAL ABSORPTION
ADVANTAGES DRAWBACKS
Not affected by acid gaspartial pressure
Low absorption of HC
In public domain
Reasonable cost ofsolvent
Extensive industrialreferences
High steamconsumption
Foaming tendency(except hot carbonate)
Boiler water for make-up
Corrosion tendency
DGEP/SCR/ED/ECP 57
PHYSICAL ABSORPTION
ADVANTAGES DRAWBACKS
Low energy requirement
Low corrosion
Remove mercaptans
Low water content inproduced gas
No need of pure watermake-up
Depends on acid gaspartial pressure andtemperature
HC absorption (Clausunit affected)
High cost of solvents
Proprietary processes
Most of conclusions are valide for the physico-chemical processes
DGEP/SCR/ED/ECP 58
PHYSICAL ADSORPTION
ADVANTAGES DRAWBACKS
Low CO2 content in theproduced gas
Low corrosion
May removemercaptans
Combined with waterdrying
Valid for low CO2 initialcontents
High regenerationtemperature (furnace)
DGEP/SCR/ED/ECP 59
MEMBRANE
ADVANTAGES DRAWBACKS
Low energyrequirement
Low corrosion
Low water content inproduced gas
No need of puresolvent make-up
Can be operated un-manned (offshore)
Depends on acid gaspartial pressure andtemperature
High residual CO2content (a few percent)
Sensitive to somecontaminants
Low life time ofmembranes (3 to 5 years)
Proprietary processes
DGEP/SCR/ED/ECP 60
GUIDELINE FOR PROCESS SELECTION
APPLICATION PROCESS NOTE
CO2 ABSORP.
BULKREMOVAL
LOW ACIDGASCONTENT
WATER WASH
MEMBRANE
DEA, aMDEA
HOTCARBONTE
PHYS.SOLVENTS
DEA, aMDEA
SMALLFLOWRATE
SENSIBLE TOCONTAMINANT
NOT WITH H2S
DGEP/SCR/ED/ECP 61
GUIDELINE FOR PROCESS SELECTION
APPLICATION PROCESS NOTE
CO2 AND H2SABSORPTION DEA, a MDEA
PHYSICALSOLVENT
HC ABSORTION(CLAUS UNIT)
SELECTIVE H2SABSORPTION GENERIC
MDEA, ADIP
SULFINOL
HC ABSORTION(CLAUS UNIT)
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GUIDELINE FOR PROCESS SELECTION
APPLICATION PROCESS NOTE
POLISHING
IRON SPONGEZnOCHARCOAL
DIRECTCONVERSIONTO SULPHUR
WASTE SOLIDTO BETREATED
LOW FLOWANDPRESSURE(EXCEPTSULFINT)
SWEETENINGWITHMERCAPTANREMOVAL
AMINE WITHMOLECULARSIEVE
SULFINOL
NOT FULLYREFERENCED
HC ABSORTION(CLAUS UNIT)