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Chin. J. Process Eng. ›› 2015, Vol. 15 ›› Issue (5): 774-780.DOI: 10.12034/j.issn.1009-606X.215265

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Absorption Process of CO2 with Diethanolamine Solution

ZHANG He ZHANG Hui LIU Ying-shu HAO Zhi-tian ZHAO Zi-ling GUO Ya-lou   

  1. School of Mechanical Engineering, University of Science and Technology Beijing School of Mechanical Engineering, University of Science and Technology Beijing Institute of Gas Separation Engineering, School of Mechanical Engineering, University of Science and Technology Beijing Institute of Gas Separation Engineering, School of Mechanical Engineering, University of Science and Technology Beijing Institute of Gas Separation Engineering, School of Mechanical Engineering, University of Science and Technology Beijing Institute of Gas Separation Engineering, School of Mechanical Engineering, University of Science and Technology Beijing
  • Received:2015-07-15 Revised:2015-08-28 Online:2015-10-20 Published:2015-10-20
  • Contact: ZHANG Hui

二乙醇胺溶液吸收CO2过程

张贺 张辉. 刘应书 郝智天 赵梓伶 郭亚楼   

  1. 北京科技大学机械工程学院 北京科技大学冶金工业节能减排北京市重点实验室 北京科技大学机械工程学院 北京科技大学机械工程学院 北京科技大学机械工程学院 北京科技大学机械工程学院
  • 通讯作者: 张辉.

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Abstract: Two-film gas transfer theory was applied to analyze carbon dioxide absorption across the gas-liquid interface with diethanolamine (DEA) solution. Mathematical models were developed to describe the dependence of CO2 transfer rate on pH value and the degree of rate enhancement due to chemical reactions with DEA. Various concentrations of carbonic species in the bulk liquid [i.e., DCDt(RNHCOO-), DCDt(HCO3-) and DCDt(CO32-)] in time were considered to affect total mass transfer rate. Various technological parameters, such as DEA concentration, CO2 flow rate and ratio of absorption blends were controlled. The results show that CO2 transfer rate is mainly contributed by CO32- and HCO3-, but the transfer rate of RNHCOO- is not significant. The CO2 transfer rate is promoted by the increase of DEA concentration, but the effect will decrease after pH value falls to 8.2. When CO2 flow rate increases, the transfer rate will increase until 70 mL/min. Blend solution is better than single DEA solution in CO2 absorption, but the effect of the ratio of blend is not significant on contribution ratio of carbonic species to total mass transfer rate.

Key words: carbon dioxide, diethanolamine, absorption, pH value, mass transfer, model

摘要： 运用双膜理论对气液两相传质进行分析，针对二乙醇胺溶液吸收CO2建立数学模型，该模型精确描述CO2传质速率对溶液pH值依赖程度及速率强化因子随化学反应进行的变化情况. 从每种含碳离子(包括CO32-, HCO3-与RNHCOO-)在不同反应阶段的浓度分布角度分析了各自对总传质速率的影响规律，实验中分别控制溶液浓度、进气流量和复合溶液配比等工艺参数. 结果表明，CO2传质速率主要受CO32-与HCO3-控制，而RNHCOO-的作用有限. 吸收液浓度提高促进传质，但当pH值降至8.2后其作用减弱；传质速率随进气流量升高而加快，70 mL/min后趋于稳定；复配溶液较单一溶液对CO2吸收速率和吸收量均有促进作用，但复配比例变化对离子贡献率影响微弱.

关键词: 二氧化碳, 二乙醇胺, 吸收, pH值, 传质, 模型

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