Experimental study on CO2 absorption into aqueous ammonia-based blended absorbents

Abstract

A crucial problem for the promising absorbent aqueous ammonia (NH3) is the low CO2 absorption rate and high ammonia volatile loss rate. This work investigated the effect of potential promoters for CO2 absorption into aqueous ammonia solutions on a wetted wall column. Monoethanolamine, sarcosinate, taurinate, glycinate, piperazine and 1-methyl piperazine were introduced to NH3 solutions as promoters. We found sarcosinate, piperazine and 1-methyl piperazine could increase the mass transfer coefficient of CO2 into the ammonia-based solutions significantly. We further undertook a detailed mass transfer study of CO2 into ammonia based blended solutions to investigate the effects of temperature and additive concentration. Besides, a novel ammonia separation method from low concentration ammonia solution by membrane vacuum regeneration was developed which could recover more than 80% of ammonia gas from low concentration ammonia.