新型相变溶剂吸收烟气中CO2的动力学研究

The emission control of CO2 in flue gas has become the focus issue. The application of phase change solvents absorbing CO2 may enormously reduce the energy consumption during the regeneration of absorbents. According to the characteristic of the coal fired flue gas , the novel liquid -liquid phase solvents for CO2 capture will be developed. When CO2 is absorbed into the sulfolane-amine mixture , the phase phenomena will be observed due to the distinct solubility of CO2. The phase change and kinetics in CO2 absorption will be studied using a wetted-wall column. The project will explore optimum composition and concentration of phase change solvents according to screening high performance mixture solvents. The effects of operating conditions, including gas flue rate, CO2 partial pressure,CO2 loading, phase change solvent concentration and temperature, on the total mass transfer rate will be investigated. The mass-transfer process model of phase change solvent absorbing CO2 is to be built according to vapor-liquid equilibrium and the steady state. Furthermore, the kinetics results and the mass-transfer process model matched; the enhancement factor of phase change solvent and the contribution of partial process to total mass-transfer resistance are obtained. As a result, it can be acquired for the rate controlling step and mass-transfer mechanism of CO2 absorption. The thermodynamics will be invesitgated to evaluate the energy consumption for the desorption as well as the thermostability. The results can provide theory basis and practical reference for developing cost-effective CO2 capture technology.

烟气CO2排放控制是国际关注的热点问题。利用相变溶剂可大大降低CO2吸收再生过程的能耗。本项目根据燃煤烟气的特点，开发新型液-液相变的CO2吸收技术。采用湿壁塔反应装置，以环丁砜/胺类混合溶液为吸收剂，利用CO2在吸收产物组分中的溶解度不同而产生分相作用，研究CO2吸收过程的相变行为特征及反应动力学机理。拟通过筛选性能优良的混合相变吸收剂，探索相变溶液的最佳组成和浓度配比；考察温度、烟气流量、CO2分压、CO2负载浓度、相变溶剂浓度等因素对总传质速率的影响；根据VLE平衡关系和稳态理论，构建基于相变溶剂吸收CO2的传质反应过程模型，并将动力学实验结果与模型耦合，获取相变溶剂的反应增强因子，揭示CO2吸收过程的速率控制步骤和传质反应过程机理；研究CO2解吸过程热力学，估算相变溶剂的解吸能耗，评价其热稳定性。研究结果可为开发高效、低能耗的烟气CO2控制技术提供理论依据与现实参考。

烟气CO2排放控制是国际关注的热点问题。利用相变溶剂可大大降低CO2吸收再生过程的能耗。本项目根据燃煤烟气的特点，开发新型液-液相变的CO2吸收技术。采用湿壁塔反应装置，以环丁砜/胺类混合溶液为吸收剂，利用CO2在吸收产物组分中的溶解度不同而产生分相作用，研究CO2吸收过程的相变行为特征及反应动力学机理。拟通过筛选性能优良的混合相变吸收剂，探索相变溶液的最佳组成和浓度配比；考察温度、烟气流量、CO2分压、CO2负载浓度、相变溶剂浓度等因素对总传质速率的影响；根据VLE平衡关系和稳态理论，构建基于相变溶剂吸收CO2的传质反应过程模型，并将动力学实验结果与模型耦合，获取相变溶剂的反应增强因子，揭示CO2吸收过程的速率控制步骤和传质反应过程机理；研究CO2解吸过程热力学，估算相变溶剂的解吸能耗，评价其热稳定性。研究结果可为开发高效、低能耗的烟气CO2控制技术提供理论依据与现实参考。.通过对上述内容的研究，我们筛选出了吸收速率高、解吸能耗低、相变过程易调控的新型环丁砜/多级胺相变溶剂体系，主要包括DETA-环丁砜体系、MEA-环丁砜体系、DEEA-TETA-环丁砜体系、MEA-正丙醇体系。明晰了CO2 在贫相和富相中的相变行为、分布特征和调控规律，揭示了新型相变溶剂吸收CO2 的传质-反应动力学机理，并获取了相变溶剂体系的再生能耗，计算结果表明开发的相变溶剂解吸能耗相对常用MEA普遍降低20-30%。项目成果包括发表研究论文7篇，SCI收录7篇，其中包括环境领域顶级期刊Environmental Science & Technology 3篇；申请发明专利1项；培养研究生2名。