High cyclic capacity amines for high efficiency CO₂scrubbing processes

摘要

A high cyclic capacity carbon dioxide scrubbing process contacts a gas stream containing carbon dioxide in a sorption zone with a liquid scrubbing solution of a low molecular weight sterically hindered amine, particularly a secondary alkanolamine or aminoether at a high concentration, typically at least 3.5M and at a temperature of at least 30° C. to sorb the carbon dioxide into the solution and form a rich stream of the sorbed carbon dioxide in the solution in the form of dissolved amine carbamate and/or alkanolamine bicarbonate. The rich stream is then passed from the sorption zone to at least one regeneration zone and the sorbed carbon dioxide is desorbed as gas from the solution to form a lean solution containing a reduced concentration of sorbed carbon dioxide relative to the rich stream; the lean stream is then returned to the sorption zone for a further sorption cycle.

主权项

1. A high cyclic capacity carbon dioxide scrubbing process which comprises:
(i) contacting a gas stream containing carbon dioxide in a sorption zone with an aqueous liquid scrubbing solution of a sterically hindered secondary amine at a total secondary amine concentration of at least 3.5M and at a temperature of at least 10° C. to sorb the carbon dioxide into the amine solution and form a rich stream of the sorbed carbon dioxide in the amine solution in the firm of amine carbamate and/or amine bicarbonate dissolved in the solution; wherein the sterically hindered secondary amine comprises a sterically hindered aminoether in which the carbon atom alpha to the nitrogen atom is a secondary carbon having one proton having a molecular weight of not more than 180; (ii) passing the rich stream from the sorption zone to at least one regeneration zone and desorbing the sorbed carbon dioxide as gas from the amine solution to form a lean solution containing a reduced concentration of sorbed carbon dioxide relative to the rich stream; and (iii) returning the lean stream to the sorption zone.