Solubility of CO2 in Aqueous Solutions of Several Classes of Amines

Aqueous solutions of amine are used for removing CO2 and H2S from natural gas streams and refinery process streams. They are also used to remove CO2 from combustion gases and may receive wide application for abatement of greenhouse gases due to their basic character.

The objective of this work is to study the absorption capacity of CO2 in aqueous amines from several classes selected by a Quantitave Structure Activity Relationship (QSAR) method in order to find new chemical solvents. Among the twenty retained molecules are morpholine, 4-methyl-morpholine, tris(hydromethyl)aminoethane, 2-2-dimethylaminoethoxy-ethanol, 1,2-bis-dimethylaminoethane, 1,2-bis-2-aminoethoxy-ethane.

In this aim we realized a static apparatus based on the drop of the pressure of CO2 contained in the reservoir. The solubilities of the previously quoted amines were determined at 2 different temperatures corresponding to the process operation: 40°C (CO2 absorption temperature) and 80°C (regeneration temperature).

The present study was carried out in the frame work of the ANR CapCO2 (Agence Nationale de la Recherche which launched a CO2 program in 2005).