Abstract: A thermodynamic model for monoethanolamine (MEA)-H₂O-CO₂ was built using the electrolyte non-random two-liquid model. Over twenty parameters were regressed from the vapor pressure and heat capacity data for MEA, data of vapor-liquid equilibrium, heat capacity and heat of mixing for MEA-H₂O, and CO₂ solubility data for MEA-H₂O-CO₂ over a wide range of temperature, concentration and CO₂ loading. The model was validated by the NMR speciation data and then used to build a process simulation for CO₂ absorption/ desorption into 30%(mass) MEA. The simulation results match the pilot plant data in literature. For 30%(mass) MEA solution, when the CO₂ removal rate in the absorber is 90%, the reboiler heat duty is the minimum by changing the mass flow ratio of liquid to gas in the absorber. The minimum reboiler heat duty is 3.64 GJ·(t CO₂)^-1, when the ratio is 2.

Key words: carbon dioxide, absorption, thermodynamics, simulation, monoethanolamine

摘要： 采用非随机双流体电解质（ENRTL）热力学模型，通过拟合单乙醇胺（MEA）的饱和蒸气压、热容数据，MEA和水（H₂O）二元体系的汽液平衡、热容、混合热数据，以及二氧化碳（CO₂）在MEA水溶液中的溶解度数据，建立了MEA吸收CO₂的热力学模型，并用核磁共振（NMR）组成数据成功地进行了验证。在此模型基础上，利用平衡级模型建立了MEA吸收/解吸CO₂的过程模拟，利用文献中中试工厂数据验证了过程模拟的准确性。对于质量分数为30%的MEA溶液，固定吸收塔CO₂去除率为90%的条件下，当吸收塔液气质量流率比值为2时，再沸器能耗最小，为3.64 GJ·（t CO₂）^-1。

关键词: CO₂, 吸收, 热力学, 模拟, 单乙醇胺