Ionic liquids as amine promoter solvents for removal of carbon dioxide

摘要

Ionic liquids are capable of acting as solvents for amine CO2 absorbent compounds in CO2 separation processes and when so used enhance the sorption of the CO2 by the amine. A cyclic sorption process for separating CO2 from a gas stream, such as flue gas or natural gas, brings the gas stream into contact with an absorbent solution of an amine CO2 sorbent in an ionic liquid solvent followed by desorbing the CO2 to regenerate the amine.

主权项

1. A cyclic process for separating CO2 from a gas stream, which process comprises:
a) contacting the gas stream with a non-aqueous absorbent comprising a solution of an amine sorbent in an ionic liquid having a counterion derived from an organic acid with a pKa of at least 0 (25° C. aqueous equivalent scale) to sorb CO2 into the solution thereby producing a rich solution containing the sorbed CO2; wherein the absorbent sorbs CO2 by stabilization of a carbamic acid species relative to a carbamate species; and b) treating the rich solution under conditions sufficient to cause desorption of at least a portion of the CO2 and to regenerate the amine.