gas sweetening

Oil & Gas Processing Plants Design and OperationTraining Course

DGEP/SCR/ED/ECP - 7/18 October 2002

GAS SWEETENING PROCESSES

DGEP/SCR/ED/ECP - 7/18 October 2002

DGEP/SCR/ED/ECP - 7/18 October 2002*

GAS SWEETENINGSALES GAS SPECIFICATIONTo meet the H2S content Specification H2S Content < 4 ppm Vol.

To increase THE GROSS CALORIFIC VALUE CO2 Removal

PROCESS CONSTRAINTSCRYOGENIC PROCESSES (Ethane extraction, LNG Manufacture) CO2 Solidification at temperatures below - 70/80C

CRUDE SWEETENING USING STRIPPING GASTo remove H2S From the Stripping Gas


GAS SWEETENING PROCESSESPROCESSES DEPENDING ON CONTAMINANTS TO BE REMOVED :

CO2 ONLY

H2S ONLY

CO2 & H2S SIMULTANEOUSLY

SELECTIVE REMOVAL OF H2S


GAS SWEETENING PROCESSESCHEMICAL ABSORPTIONPHYSICAL ABSORPTIONPHYSICO- CHEMICAL ABSORPTIONPHYSICAL ADSORPTIONCRYOGENIC PROCESS (CO2 Removal only)MEMBRANESDirect Conversion To SULPHUR


CHEMICAL ABSORPTION


CHEMICAL ABSORPTION


CHEMICAL ABSORPTION


CHEMICAL ABSORPTION


CHEMICAL ABSORPTION


CHEMICAL ABSORPTION


CHEMICAL ABSORPTION


CHEMICAL ABSORPTION



DEA PROCESSADVANTAGES :No degradation by COS & CS2Absorption of mercaptansGood stabilitylow absorption of HCNo reclaimerreduced vaporization lossespublicDISADVANTAGES :Higher circulation rate (lower activity)Higher utility requirementsOxydationNo selectivity between H2S & CO2UTILIZATION : H2S, CO2, COS, CS2, RSH (up to 20%)SPLIT FLOWSNEA-DEA : higher concentration


MDEA PROCESS


MDEA PROCESS


CHEMICAL ABSORPTION


HOT CARBONATE PROCESS


HOT CARBONATE PROCESSADVANTAGES :No degradation by COS & CS2Good chemical stabilityNo reaction with airlow absorption of HCNo reclaimerLow heat requirement (50% of corresponding amine unit)DISADVANTAGES :Low reactivity with H2SNo mercaptans absorptionhigher water content of treated gaslicensing feeUTILIZATION : HIGH CO2if H2S in two steps :K2CO3 + mol. SievesK2CO3 + AMINE SPLIT FLOW : solution cooling / two stages process / LO HEAT






PHYSICAL ABSORPTION


PHYSICAL ABSORPTIONWATER WASH : partial treatmentSELEXOL PROCESS : NORTON (dimethyl ether of polyethylene glycol) up to 65% of CO2light gas sweeteningregeneration by flashFLUOR SOLVENT : propylene carbonateup to 50% of CO2Gas dehydration by as solvent and heat regenerationPURISOL : LURGISelective process to remove H2S even in case of low H2S/CO2 ratioGas dehydration by add solvent and heat regenerationRECTISOL : LURGI Refrigerated solution of MeOH (high selectivity for CO2)ESTASOLVAN : UHDE Recompression of flashed gasSEPASOLV-MPE : BASF

Recoompression of flashed gas


SELEXOL PROCESS


MORPHYSORB PROCESS



PHYSICAL ABSORPTION


AMINE PROCESS GUIDELINE


PHYSICO-CHEMICAL PROCESS


SULFINOL PROCESS


CHEMICO-PHYSICAL ABSORPTION


SULIFINOL (SHELL)


SULFINOL (SHELL)


HYBRISOL PROCESS


HYBRISOL PROCESS


PHYSICAL ADSORPTION


PHYSICAL ADSORPTION


PHYSICAL ADSORPTION


CRYOGENIC PROCESS


CRYOGENIC PROCESS


CO2 REMOVAL BY CRYOGENICS


SPREX


PERMEATION (Membranes)


MEMBRANE PROCESS

MEMBRANE TECHNOLOGY For bulk removal of CO2


MEMBRANE PROCESS


FIBER MEMBRANE


FIBER MEMBRANE


FIBER MEMBRANE


TYPICAL ONE STAGE MEMBRANE PFD


MEMBRANE PROCESS


MEMBRANE PROCESS


MEMBRANE PROCESS


MEMBRANE PROCESS


PROCESS COMPARISONDIRECT CONVERSIONTO SULPHUR


PROCESS COMPARISONABSORPTION :

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


SULFINT (IFP)


DIRECT CONVERSION TO SULPHURFIELD OF APPLICATIONLOW FLOWRATELOW PRESSURE (EXCEPT SULFINT FROM IFP)LOW H2S CONTENT ( < 1000 ppm )

LICENSORSUS FILTER ( LO-CAT)IFP with Le Gaz Intgral (SULFINT)SHELL ( SULFEROX )


PROCESS COMPARISONGUIDE LINE FOR PROCESS SELECTION


CHEMICAL ABSORPTION

2/1

ADVANTAGES

DRAWBACKS

Not affected by acid gas partial pressure

Low absorption of HC

In public domain

Reasonable cost of solvent

Extensive industrial references

High steam consumption

Foaming tendency (except hot carbonate)

Boiler water for make-up

Corrosion tendency

Document dans GasSweetening-SP01-JG



PHYSICAL ABSORPTIONMost of conclusions are valide for the physico-chemical processes

2/1

ADVANTAGES

DRAWBACKS

Low energy requirement

Low corrosion

Remove mercaptans

Low water content in produced gas

No need of pure water make-up

Depends on acid gas partial pressure and temperature

HC absorption (Claus unit affected)

High cost of solvents

Proprietary processes




PHYSICAL ADSORPTION

2/1

ADVANTAGES

DRAWBACKS

Low CO2 content in the produced gas

Low corrosion

May remove mercaptans

Combined with water drying

Valid for low CO2 initial contents

High regeneration temperature (furnace)




MEMBRANE

2/1

ADVANTAGES

DRAWBACKS

Low energy requirement

Low corrosion

Low water content in produced gas

No need of pure solvent make-up

Can be operated un-manned (offshore)

Depends on acid gas partial pressure and temperature

High residual CO2 content (a few percent)

Sensitive to some contaminants

Low life time of membranes (3 to 5 years)

Proprietary processes




GUIDELINE FOR PROCESS SELECTION

2/1

APPLICATION

PROCESS

NOTE

CO2 ABSORP.

BULK REMOVAL

LOW ACID GAS CONTENT

WATER WASH

MEMBRANE

DEA, aMDEA

HOT CARBONTE

PHYS. SOLVENTS

DEA, aMDEA

SMALL FLOWRATE

SENSIBLE TO CONTAMINANT

NOT WITH H2S





2/1

APPLICATION

PROCESS

NOTE

CO2 AND H2S ABSORPTION

DEA, a MDEA

PHYSICAL SOLVENT

HC ABSORTION (CLAUS UNIT)

SELECTIVE H2S ABSORPTION

GENERIC MDEA, ADIP

SULFINOL






2/1

APPLICATION

PROCESS

NOTE

POLISHING

IRON SPONGE ZnO CHARCOAL

DIRECT CONVERSION TO SULPHUR

WASTE SOLID TO BE TREATED

LOW FLOW AND PRESSURE (EXCEPT SULFINT)

SWEETENING WITH MERCAPTAN REMOVAL

AMINE WITH MOLECULAR SIEVE

SULFINOL

NOT FULLY REFERENCED




gas sweetening

Documents

h2s co2utilization

high co2if h2s

mdea processdgepscredecp

stages process

lurgiselective process

ccrude sweetening

flashfluor solvent

heat regenerationrectisol