System and process for capture of H2S from gaseous process streams and process for regeneration of the capture agent
AssigneeBattelle Memorial Institute
InventorsDavid J. Heldebrant, Phillip K. Koech, James E. Rainbolt, Mark D. Bearden, Feng Zheng
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Abstract
A system and process are disclosed for selective removal and recovery of H2S from a gaseous volume, e.g., from natural gas. Anhydrous organic, sorbents chemically capture H2S gas to form hydrosulfide salts. Regeneration of the capture solvent involves addition of an anti-solvent that releases the captured H2S gas from the capture sorbent. The capture sorbent and anti-solvent are reactivated for reuse, e.g., by simple distillation.
Claims27
A method for chemically-selective removal of H2S from a gaseous volume, the method comprising:
- chemically binding H2S to a capture sorbent comprising an anhydrous organic compound with a structural formula as follows:
- where R1 and R2 are alkyl-containing groups;
- (n) is a number of carbons greater than 0;
- and (X) is a polar functional group, the binding forming a switchable hydrosulfide salt in the capture sorbent;
- and
- regenerating the capture sorbent by adding a selected quantity of an anti-solvent comprising a non-polar organic compound miscible in the capture sorbent that changes the polarity of the capture sorbent releasing the chemically-bound H2S from the switchable hydrosulfide salt.
A system for reversible capture and recovery of H2S from a gaseous volume, the system comprising:
- an absorption chamber containing an anhydrous alkanolamine capture sorbent that chemically binds and removes H2S from the gaseous volume when presented therein that forms a switchable hydrosulfide salt;
- and
- a stripping chamber operatively coupled to the absorption chamber configured to mix an anti-solvent comprising a non-polar organic compound with the switchable hydrosulfide salt, the anti-solvent having a miscibility in the capture sorbent when mixed therewith sufficient to change the polarity of the capture sorbent that releases chemically bound H2S from the switchable hydrosulfide salt and regenerates the anhydrous capture sorbent.
A process for capture and release of H2S, comprising:
- capturing H2S with an anhydrous capture sorbent to form a switchable ionic liquid;
- regenerating the anhydrous capture sorbent by contacting the switchable ionic liquid with an anti-solvent comprising a non-polar organic compound;
- and
- reactivating the anhydrous capture sorbent for reuse by distilling the anti-solvent from the anhydrous capture sorbent or by distilling the anhydrous capture sorbent from the anti-solvent based on their volatility differences.
A process for capture and release of H2S, comprising:
- capturing H2S with an anhydrous capture sorbent to form a switchable ionic liquid;
- regenerating the anhydrous capture sorbent by contacting the switchable ionic liquid with an anti-solvent comprising a non-polar organic compound;
- and
- reactivating the anhydrous capture sorbent by cooling the anti-solvent to a temperature below the freezing point of the anti-solvent to freeze the anti-solvent and separating the anti-solvent from the anhydrous capture sorbent.
A process for capture and release of H2S comprising:
- capturing H2S with an anhydrous capture sorbent to form a switchable ionic liquid;
- regenerating the anhydrous capture sorbent by contacting the switchable ionic liquid with an anti-solvent comprising a non-polar organic compound;
- and
- reactivating the anhydrous capture sorbent by cooling the anhydrous capture sorbent containing the anti-solvent to a temperature below the miscibility temperature of the anti-solvent to phase separate the anti-solvent from the anhydrous capture sorbent into at least two layers and decanting the anti-solvent from the anhydrous capture sorbent or vice versa to remove the anti-solvent from the anhydrous capture sorbent.
A process for chemically-selective removal of H2S from a gaseous volume for collection thereof, comprising:
- capturing H2S present in the gaseous volume with an anhydrous alkanolamine capture sorbent to form a switchable hydrosulfide salt;
- regenerating the anhydrous capture sorbent by contacting the switchable hydrosulfide salt in the capture sorbent with an anti-solvent comprising a non-polar organic compound that when mixed therewith changes the polarity of the capture sorbent releasing the chemically bound H2S from the switchable hydrosulfide salt thereby regenerating the anhydrous capture sorbent;
- and
- reactivating the anhydrous capture sorbent by cooling the anti-solvent to a temperature below the freezing point of the anti-solvent and removing the anti-solvent from the anhydrous capture sorbent.
Dependencies are inferred from the claim text.