Simultaneous absorption of carbon dioxide and hydrogen sulfide into aqueous blends of 2-amino-2-methyl-1-propanol and diethanolamine

Abstract

This work presents an experimental and theoretical investigation of the simultaneous absorption of CO 2 and H 2 S into aqueous blends of 2-amino-2-methyl-1-propanol (AMP) and diethanolamine (DEA). The effect of contact time, temperature and amine concentration on the rate of absorption and the selectivity were studied by absorption experiments in a wetted wall column at atmospheric pressure and constant feed gas ratio. The diffusion–reaction processes for CO 2 and H 2 S mass transfer in blended amines are modeled according to Higbie's penetration theory with the assumption that all reactions are reversible. The blended amine solvent (AMP+DEA+ H 2 O ) has been found to be an efficient mixed solvent for simultaneous absorption of CO 2 and H 2 S . By varying the relative amounts of AMP and DEA the blended amine solvent can be used as an H 2 S -selective solvent or an efficient solvent for total removal of CO 2 and H 2 S from the gas streams. Predicted results, based on the kinetics-equilibrium-mass transfer coupled model developed in this work, are found to be in good agreement with the experimental results of rates of absorption of CO 2 and H 2 S into (AMP+DEA+ H 2 O ) of this work.