The Absorption Of Carbon Dioxide By Amines In Packed Tower

CO2 as the main greenhouse gas, accounting for 60% of all greenhouse gases. In recent years, with the industry's rapid development, more and more fossil fuel burning and reduction of vegetation, resulting in CO2 increase every year. Amine method for CO2 absorption appeared in the 1930s',and it has became a major industrial CO2 purification methods after its industrialization.In this study, we used Aspen Plus process simulation software to design and build a small pilot-plant to investigate the performance of CO2 absorption in different amine solutions. The pilot-plant includes two parts(absorber tower and regeneration tower),and we used pecked tower in the two parts.A study of carbon dioxide absorption and regeneration in aqueous amine solutions, consisting of 20%2-(aminoethylamino) ethanol (AEE)+2%N-methyldiethanolamine (MDEA) and 20% monoethylamino(MEA)+2% N-methyldiethanolamine (MDEA) has been carried out in a packed tower. The results showed that the CO2 absorption in 20%AEE+2%MDEA better than 20%MEA+2%MDEA and The CO2 regeneration near the same in both blended amine. Also, The volumetric overall mass transfer coefficient (KGav) of dilute CO2 absorption into AEE/MDEA was measured. The KGav value was evaluated over the ranges of CO2 mole flow rate in inlet gas, overall gas flow rate and liquid flow rate. As a resulte,the KGav could be remarkably improved by increasing CO2 mole flow rate in inlet gas, overall gas flow rate and liquid flow rate.As the aqueous regeneration temperature above 100℃, the evaporation of water in water and amine aqueous at regeneration process, leading to most of the energy consumption. Therefore, this study used a relatively high boiling point solvent (N-methyl-pyrrolidone) to research the amine absorption of CO2. Experimental results show that at the same amine concentration, the absorption of CO2 into the water do better than into the N-methyl-pyrrolido ne. But the regeneration energy consumption decreased with the N-methyl-pyrrolidone as solvent.In industrial production because of the degradation of amine, leading to the absorbent consumption. In this study the concentration of amine was determined by acid-base titration. we researched MEA's degradation under the conditions of O2, air, CO2/O2 at the 120℃. Experiments show that not only the access of pure O2, CO2/O2 mixed gas, CO2/air mixture can leading to the degradation of ME A, but also the CO2 can leading to the degradation of MEA.