关键词: 二氧化碳捕集, 核磁共振, 吸收, 解吸

Abstract: 13C NMR spectroscopy is a suitable analytical method to get quantitative information on the species distribution in aqueous amine solutions loaded with carbon dioxide (CO2). 13C NMR is used for quantitative analysis on CO2 absorption and desorption in monoethanolamine (MEA) solution. Temperatures of absorption and desorption experiments are 313K and 393K，respectively. From 13C NMR spectroscopy，it is found that the main MEA species under the absorption conditions studied are free amine，protonated amine，MEA carbamate，and HCO3?/CO32?. At absorption step，MEA carbamate is produced first，when CO2 loading is getting higher to 0.455mol CO2/mol amine in this experiment，HCO3?/CO32? appears. The mole fraction of the MEA carbamate increases first with absorption time，reaches their maximum，and then decreases. The mole fraction of HCO3?/CO32? consistently increases with the increase of absorption time. At the desorption step，the mole fraction of MEA carbamate increases at early stage，reaches a maximum，and then decreases up to the end. After the desorption process，all HCO3?/CO32? can be stripped while about 75% of MEA carbamate still exist in the MEA solution.

Key words: carbon dioxide capture, nuclear magnetic resonance（NMR）, absorption, desorption