Process for separating CO.sub.2 and H.sub.2 S from hydrocarbons
AssigneeAir Products and Chemicals, Inc.
InventorsMichael S. K. Chen, Stephen P. Goff, James VanOmmeren
Life of this patent
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Abstract
The present invention involves a process for separating components of a feed gas containing acid gases and hydrocarbons to form a CO.sub.2 -rich stream, an H.sub.2 S-rich stream and a hydrocarbon-rich stream. Separation is achieved by initially passing the feed gas through a plurality of membrane separation units to produce a hydrocarbon stream and an acid gas stream. The acid gas stream undergoes further separation to produce a CO.sub.2 -rich product stream and an H.sub.2 S-rich stream. This process is especially adaptable for treating natural gas streams and gas streams resulting from enhanced oil recovery operations.
Claims12
A process for separating components of a feed gas containing CO.sub.2, H.sub.2 S and C.sub.1 and higher hydrocarbons to form a CO.sub.2 -rich stream, an H.sub.2 S-rich stream and a hydrocarbon-rich stream, said process comprising:
- (a) passing said feed gas to a plurality of membrane separation units to form a plurality of acid gas-rich streams and a hydrocarbon-rich stream;
- (b) compressing at least one acid gas-rich stream and passing said stream back through at least one membrane separation unit to further remove hydrocarbons and thereby form an additional hydrocarbon-rich stream;
- (c) combining said hydrocarbon-rich streams to form a combined hydrocarbon-rich stream containing less than 10 mole% CO.sub.2 ;
- (d) separating said combined hydrocarbon-rich stream to form a methane-rich stream and a higher hydrocarbon-rich stream;
- (e) combining the acid gas-rich streams to form a combined acid gas-rich stream;
- (f) compressing said combined acid gas-rich stream;
- (g) contacting said combined acid gas-rich stream with a solvent capable of absorbing H.sub.2 S thereby forming a CO.sub.2 product stream containing less than 100 ppm H.sub.2 S and an H.sub.2 S-rich solvent stream;
- (h) passing said H.sub.2 S-rich solvent stream through a series of flash units to remove CO.sub.2 from the H.sub.2 S-rich solvent stream;
- (i) subsequently contacting the H.sub.2 S-rich solvent stream with the methane-rich stream in step (d) to further remove CO.sub.2 ;
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- (j) thermally treating the resultant H.sub.2 S-rich solvent stream to form an H.sub.2 S-rich product stream having a concentration of at least 30 mole% H.sub.2 S and a regenerated solvent stream.
A process for separating components of a feed gas containing acid gases and C.sub.1 and higher hydrocarbons to form a CO.sub.2 -rich stream, an H.sub.2 S-rich stream and a hydrocarbon-rich stream, said process comprising:
- (a) passing said feed gas to a plurality of membrane separation units to form a plurality of acid gas-rich streams and hydrocarbon-rich stream;
- (b) compressing at least one acid gas-rich stream and passing said stream back through at least one membrane separation unit to further remove hydrocarbons and thereby form an additional hydrocarbon-rich stream;
- (c) combining the hydrocarbon-rich streams, and subsequently passing said combined hydrocarbon stream, containing less than about 10 mole% CO.sub.2, to a natural gas processing plant to form a methane-rich stream and a higher hydrocarbon-rich stream;
- (d) combining the acid gas-rich streams and subsequently passing said combined stream through successive step compression to a fractionation column containing a solvent capable of selectively removing H.sub.2 S thereby forming an H.sub.2 S-rich solvent stream and a CO.sub.2 product stream containing less than 100 ppm H.sub.2 S;
- (e) passing said H.sub.2 S-rich solvent stream through a series of flash units to separate CO.sub.2 from the H.sub.2 S-rich solvent;
- (f) subsequently introducing said H.sub.2 S-rich solvent stream into an H.sub.2 S concentrator where residual CO.sub.2 is removed from said solvent stream by contact with the methane-rich stream produced in step (c);
- (g) passing the resultant H.sub.2 S-rich solvent stream to an H.sub.2 S stripping column to form an H.sub.2 S-rich product stream, having a concentration of at least 30 mole% H.sub.2 S, and a regenerated solvent stream;
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- (h) recycling said solvent stream back to the H.sub.2 S absorption column.
Dependencies are inferred from the claim text.