Removal of carbon dioxide from flue gases

Abstract

A description is given of a process for removing carbon dioxide from gas streams in which the partial pressure of the carbon dioxide is less than 200 mbar, in particular flue gases, the gas stream being contacted with a liquid absorption medium which comprises an aqueous solution (A) of a tertiary aliphatic alkanolamine and (B) an activator of the formula R1—NH—R2—NH2, where R1 is C1-C6-alkyl and R2 is C2-C6-alkylene, the sum of the concentrations of A and B being 2.5 to 7 mol/l, and the molar ratio of B to A being in the range of 1:3 to 1.5:1. The activator is, for example, 3-methylaminopropylamine, the tertiary aliphatic amine methyldiethanolamine, methyldiisopropanolamine or n-butyldiethanolamine. The process permits substantial removal of carbon dioxide and the regeneration of the absorption medium is possible with relatively low energy consumption.

Dependencies are inferred from the claim text.