Absorption of Carbon Dioxide in Aqueous Solutions of N-methyldiethanolamine Mixtures

Carbon dioxide (CO₂) is one of the greenhouse gases (GHG) that has contributed to the global warming problem. Carbon dioxide is produced in large quantity from coal-fired power plants, iron and steel production, cement production, chemical and petrochemical industries, natural gas purification, and transportation. Some efforts to reduce the CO₂ emissions to the atmosphere are then required. Amine-based absorption may be an option for post-combustion capture. The objective of this study is to measure the effect of promoter addition as well as MDEA concentration for the CO₂ absorption into the aqueous solutions of MDEA to improve its performances, i.e. increasing the absorption rate and the absorption capacity. Absorption of CO₂ in aqueous solutions of MDEA mixtures were measured at 40 °C in a bubble tank reactor. The systems tested were the mixtures of 30 wt% MDEA with 5 and 10 wt% BEA and the mixtures of 40 and 50 wt% MDEA with 6 wt% AEEA. It was found that for MDEA-BEA-H₂O mixtures, the higher the promoter concentraation the higher the CO₂ absorption rate, while for the MDEA-AEEA-H₂O mixtures, the higher the MDEA concentration the lower the CO₂ absorption rate.