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US 5,393,505 AGranted
Process for increasing the acid gas absorption capacity of contaminated alkanolamine solutions
AssigneeMobil Oil Corporation
InventorCostandi A. Audeh
Life of this patent
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Abstract
The present invention includes a process for rejuvenating a spent aqueous alkanolamine solution comprising use of alkyl-substituted ammonium-containing organic base treatment to remove inorganic ions.
Claims14
A process for rejuvenating a spent aqueous alkanolamine solution comprising the steps of:
- (a) providing a fresh aqueous alkanolamine solution having alkanolamine concentration sufficient to effectively sorb an acid gas selected from the group consisting of H.sub.2 S, CO.sub.2, or both from a gaseous hydrocarbon stream having H.sub.2 S, CO.sub.2, or both dissolved therein;
- (b) contacting said fresh aqueous alkanolamine solution with said hydrocarbon gas stream of step (a) whereby said fresh aqueous alkanolamine solution is enriched in said acid gas sorbed from said gaseous hydrocarbon stream;
- (c) stripping said acid gas from said enriched alkanolamine solution to produce an acid-lean alkanolamine solution;
- (d) recycling said acid-lean alkanolamine solution of step (c) to said contacting step (b);
- (e) sequentially repeating steps (b), (c), and (d) to evolve a spent alkanolamine solution which, in its acid-lean form, is characterized by reduced acid gas sorption capacity in comparison with said fresh aqueous alkanolamine solution;
- (f) removing inorganic ions from said spent alkanolamine solution;
- (g) heating said spent alkanolamine solution of step (f) at temperature of from about 220.degree. to about 275.degree. C. for time of from about 0.25 to about 2 hours in the absence of added catalyst;
- (h) admixing said heat-treated spent alkanolamine solution of step (g) with an aqueous solution containing from about 0.1 to about 20 weight percent of at least one alkyl-substituted ammonium-containing organic base which evolves no inorganic ionic constitutent upon dissolution in said spent alkanolamine solution and heating said admixture to reflux for time sufficient to produce a rejuvenated alkanolamine solution having at least about 80% of the acid gas sorption capacity of said fresh alkanolamine solution whereby the content of inorganic ionic constituent in said rejuvenated alkanolamine solution is less than when the same process is carried out with a base which forms an inorganic ionic constituent;
- (i) charging said rejuvenated alkanolamine solution to said recycling step (d).
6 more elements
A process for rejuvenating a spent aqueous alkanolamine solution comprising the steps of:
- (a) providing a fresh aqueous alkanolamine solution having alkanolamine concentration sufficient to effectively sorb an acid gas selected from the group consisting of H.sub.2 S, CO.sub.2, or both from a gaseous hydrocarbon stream having H.sub.2 S, CO.sub.2, or both dissolved therein;
- (b) contacting said fresh aqueous alkanolamine solution with said hydrocarbon gas stream of step (a) whereby said fresh aqueous alkanolamine solution is enriched in said acid gas sorbed from said gaseous hydrocarbon stream;
- (c) stripping said acid gas from said enriched alkanolamine solution to produce an acid-lean alkanolamine solution;
- (d) recycling said acid-lean alkanolamine solution of step (c) to said contacting step (b);
- (e) sequentially repeating steps (b), (c), and (d) to evolve a spent alkanolamine solution which, in its acid-lean form, is characterized by reduced acid gas sorption capacity in comparison with said fresh aqueous alkanolamine solution;
- (f) removing inorganic ions from said spent alkanolamine solution;
- (g) heating said spent alkanolamine solution of step (f) at temperature of from about 220.degree. to about 275.degree. C. for time of from about 0.25 to about 2 hours in the absence of added catalyst;
- (h) admixing said heat-treated spent alkanolamine solution of step (g) with from about 0.1 to about 20 weight percent of at least one organic base selected from the group consisting of the tetraalkylammonium hydroxides which evolves no inorganic ionic constitutent upon dissolution in said spent alkanolamine solution and heating said admixture to reflux for time sufficient to produce a rejuvenated alkanolamine solution having at least about 80% of the acid gas sorption capacity of said fresh alkanolamine solution whereby the content of inorganic ionic constituent in said rejuvenated alkanolamine solution is less than when the same process is carried out with a base which forms an inorganic ionic constituent;
- (i) charging said rejuvenated alkanolamine solution to said recycling step (d).
6 more elements
Dependencies are inferred from the claim text.