The Activator Mechanism of Piperazine in Aqueous Methyldiethanolamine Solutions

Abstract

Piperazine (PZ) is added to aqueous methyldiethanolamine (MDEA) solutions to achieve a greater CO2 absorption in CO2 capture technology. It is referred to as “activated MDEA solutions” in the industry. However, does PZ really activate rate the CO2 absorption of MDEA, or do PZ and MDEA just have parallel reactions with CO2, the mechanism is not clear. In this work, a semi-batch stirred cell with CO2 continuous operation was used to investigate the “activation” mechanism of PZ in aqueous MDEA solutions. As a comparison, kinetics of CO2 absorbed in MDEA + MEA solution and PZ aqueous solution respectively were performed at the same conditions as MDEA + PZ solution.