Alkanolamine CO₂scrubbing process

摘要

A CO2 amine scrubbing process uses an absorbent mixture consisting of an alkanolamine CO2 sorbent in combination with a non-nucleophilic base. The alkanolamine has oxygen and nitrogen sites capable of nucleophilic attack at the CO2 carbon atom. The nucleophilic addition is promoted in the presence of the non-nucleophilic, relatively stronger base, acting as a proton acceptor. The non-nucleophilic base promoter, which may also act as a solvent for the alkanolamine, can promote reaction with the CO2 at each of the reactive hydroxyl and nucleophilic amine group(s) of the alkanolamines. In the case of primary amino alkanolamines the CO2 may be taken up by a double carboxylation reaction in which two moles of CO2 are taken up by the reacting primary amine groups.

主权项

1. A cyclic process for separating CO2 from a gas stream, which process comprises contacting the gas stream with an absorbent comprising an alkanolamine CO2 sorbent and a non-nucleophilic base, to form a reaction product by carbonation of oxygen(s) on the hydroxyl group(s) and carboxylation of nitrogen(s) of the amine group(s) of the alkanolamine so as to sorb CO2 in the sorbent; wherein the ratio of non-nucleophilic base to alkanolamine is at least 1:1.