Comparison and selection of amine-based absorbents in membrane vacuum regeneration process for CO2 capture with low energy cost

摘要

Membrane vacuum regeneration (MVR) technology is a novel method to regenerate CO2 rich solvent at low temperature (around 348K) for CO2 chemical absorption process. In this study, MVR behaviors for 15 different amine-based absorbents were investigated to discuss the relationships between absorbent chemical structures and vacuum regeneration behavior by screening experiments. The results show that more hydroxyl group, shorter carbon chain length bonded at the active nitrogen atom and the existence of methyl group could elevate the CO2 stripping rate; for polyamines, average CO2 stripping rate increases with amine group number from 2 to 4 but then falls as amine group number further increases to 5; hydroxyl group substitution on carbon atom could improve the MVR performance and substitution on a-carbon has more significant effect than substitution on p-carbon. Furthermore, by the overall comparison of all amine-based absorbents studied, triethylenetetramine (TETA), 2-amino-2-hydroxymethyl-1,3-propanediol (THAM), 2-amino-2-methyl-l-propanol (AMP), 2-amino-2-ethyl-1,3-propanediol (AEPD) and tetraethylenepentamine (TEPA) are the recommendations to decrease regeneration energy consumption significantly in MVR technology.