Selective absorption of H2S and CO2 from simulated coke oven gas by aqueous blends of N-methyldiethanolamine and tetramethylammonium glycine

Tetramethylammonium glycine ([N 1111 ][Gly]) can be completely ionized into cation [N 1111 ] + and anion [Gly] - in aqueous solution. The anion contains an amino -NH 2 and a carboxyl -COO - , both of which can react with hydrogen sulfide (H 2 S). Therefore, [N 1111 ][Gly] was used to promote the selective absorption of H 2 S in coke oven gas (COG) by N-methyldiethanolamine (MDEA). The absorption performance and selectivity of H 2 S in the aqueous solution of MDEA-[N 1111 ][Gly] were investigated. The effects of MDEA mass fraction, [N 1111 ][Gly] mass fraction, temperature, H 2 S partial pressure and CO 2 partial pressure on the absorption capacity and selectivity were clarified. The results showed that an aqueous solution of MDEA-[N 1111 ][Gly] has good selectivity for H 2 S in COG. The absorption capacity was large and the mass fraction of the solute in the absorbent reached more than 0.55, thereby having outstanding advantages in the aspects of saving energy consumption and operating cost and having a good application potential.