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

摘要： 13C NMR是一种有效的测定有机胺与CO2反应过程中离子浓度变化的检测手段。本文采用13C NMR分析了一乙醇胺（MEA）吸收与解吸CO2过程，吸收与解吸实验温度分别在313K和393K下进行。结果表明，吸收CO2过程中生成了MEA氨基甲酸盐、质子胺MEAH+与HCO3?/CO32?，并且CO2与MEA反应时先生成MEA氨基甲酸盐，当溶液吸收的CO2担载量达到0.455molCO2/mol 胺时，才产生HCO3?/CO32?离子。在MEA吸收CO2过程中，MEA氨基甲酸盐的摩尔分数先增加后减少。在解吸过程中，MEA氨基甲酸盐的摩尔分数同样先增加后减少。HCO3?/CO32?在解吸过程中很容易就能被解吸，而生成的MEA氨基甲酸盐中大约有75%在解吸过程中并没有被解吸。

关键词: 二氧化碳捕集, 核磁共振, 吸收, 解吸