失活钙基吸收剂环境中自活化机理  

Self-activation mechanism of the spent calcium-sorbent under environmental conditions

作　　者：叶江明[1] 梁绍华[1] 张思文[1] 孙荣岳[1] 毕小龙[1] YE Jiangming;LIANG Shaohua;ZHANG Siwen;SUN Rongyue;BI Xiaolong(School of Energy and Power Engineering, Nanjing Institute of Technology, Nanjing 211167, Jiangsu, China)

机构地区：[1]南京工程学院能源与动力工程学院

出　　处：《化工进展》2019年第9期4302-4307,共6页Chemical Industry and Engineering Progress

基　　金：国家自然科学基金(51706094);南京工程学院引进人才科研启动基金(YKJ201407)

摘　　要：将经历多次循环后失活的钙基吸收剂置于环境中吸水自活化,通过XRD分析了自活化过程吸收剂物相演变规律,在双固定床反应器系统上分析了吸水率对失活钙基吸收剂循环捕集CO2性能的影响规律,通过SEM和N2吸附分析了自活化提高钙基吸收剂循环碳酸化转化率的机理。结果表明:失活钙基吸收剂首先吸收环境中水分生成Ca(OH)2,当吸水率达到100%后继续吸水生成Ca(OH)2·2H2O,自活化极限为170%;自活化可以提高失活钙基吸收剂循环碳酸化转化率,自活化后钙基吸收剂循环捕集CO2性能与吸水率呈线性比例关系,重复自活化可再次提高吸收剂循环碳酸化转化率;自活化过程中,失活钙基吸收剂颗粒表面重新生成孔隙,比孔容和比表面积增加,有利于吸收剂中CO2的扩散,因此自活化后钙基吸收剂循环捕集CO2性能提高。The spent Ca-based sorbent after multiple calcination/carbonation cycles was put in the natural environment to be activated by absorbing the water in the environment. XRD analysis was employed to analyze the phase transition of the sorbent during the self-activation process. The CO2 capture capacity of the sorbent after self-activation was then tested in a dual fixed-bed reactor. SEM and N2 adsorption were employed to explain why self-activation process can enhance the CO2 capture capacity of the spent sorbent. The results showed that the spent sorbent firstly absorbed the water in the environment to form Ca(OH)2. The CaO in the sorbent completely converted to Ca(OH)2 when the value of φ was 100%, and after that the sorbent continued to adsorb water to form Ca(OH)2?2H2O until the value of φ reach 170%. The self-activation process can enhance the carbonation conversion of the spent sorbent. The CO2 capture capacity of the sorbent after self-activation process was proportional to the value of φ. Repetitive self-activation can enhance the carbonation conversion of the sorbent once again. Many new pores were formed on the grain surface of the spent sorbent during the self-activation process, and the values of pore volume and BET surface area increased, which made it easier for the diffusion of CO2 in the sorbent to react with CaO. That is why self-activation process can enhance the CO2 capture capacity of the spent sorbent.

关 键 词：钙循环 失活钙基吸收剂 自活化机理 

分 类 号：TQ534.9[化学工程—煤化学工程]