变温吸附碳捕集系统能效性能实验研究

Experimental investigation on energy-efficiency performance of temperature swing adsorption system for CO2 capture

燃烧后CO2捕集技术(PCC)因易于与既有电厂结合而被认为是一项减少二氧化碳排放的重要技术。化学吸收、吸附和膜分离是PCC的主流技术。在CO2吸附技术类中,变温吸附(TSA)是一种有效的吸附方法。近年来,TSA技术的能源消耗和能源转换效率问题成为人们对其大规模部署的关注焦点。然而,大多数的研究都是将数学模型和仿真方法应用于TSA的性能评估,缺乏足够的实验研究支持。为了对TSA系统的能源转化效率进行实验分析,开发了一套四步法TSA系统,能效性能是基本分离性能外的主要考察指标。实验采用沸石13X-APG作为吸附剂材料,根据实验测得的两组吸附等温线,计算了CO2/N2的吸附选择性系数。通过进气CO2浓度、解吸时间、吸附温度和解吸温度对纯度、回收率、单位能耗和第二定律效率的影响分析,得到了4组实验结果。结果表明,第二定律效率的范围为3.24%~9.23%,回收率和纯度最高分别为83.97%和94.70%。解吸温度和进气CO2浓度的升高,吸附温度的降低有利于分离及能效性能提升。延长解吸时间有利于分离和能效提升,但过长的操作时间反而使得效果变差,这会对工程中的运行策略优化产生积极的指导意义。

Post-combustion CO2 capture(PCC)is considered to be an important technology for reducing carbon dioxide emissions owing to its easy retrofit to power plants.Chemical absorption,adsorption and membrane separation are typical mainstreams in PCC.In technological cluster of CO2 adsorption,temperature swing adsorption(TSA)is one of efficient methods.In recent years,the topic on energy consumption and energy efficiency of TSA is emerging as an urgent response to the possible large-scale deployment of CCS.However,most studies apply mathematical model and simulation method for performance assessment for TSA,without enough specific supports from experiment researches.To conduct an experiment-guided analysis on the energy-efficiency of TSA,a 4-step TSA apparatus was designed and developed.The separation and energy-efficiency performance are the main performance indicators in the analysis.Zeolite 13X-APG was employed in experiment and its selectivity of CO2 over N2 was obtained according to isotherms of two components measured experimentally.Four groups of experiment results were obtained for affect analysis from CO2 concentration,desorption duration,adsorption temperature and desorption temperature to the purity,recovery rate,specific energy consumption and second-law efficiency.The results show that the range of second-law efficiency is between 3.24%and 9.23%with the maximum recovery rate of 83.97%and purity of 94.70%.Increase of desorption temperature and CO2 concentration,decrease of adsorption temperature lead to the improvement of separation and energy-efficiency performance.Extending the desorption time benefits the separation performance.However,such longer operation time probably causes a bad performance,which may be propitious to the optimization of operation strategy for TSA system.