气凝胶型钾基吸收剂脱碳机理研究

Using potassium-based sorbent for post-combustion CO2 capture technology is thought to be one of the innovating and interesting methods due to the high CO2 sorption performance, high cyclic utilization efficiency, low corrosion for device and so on. The purpose of this program is to study the CO2 sorption mechanism of K-based sorbent and develop an aerogel sorbent combining the advantage of both organic and inorganic sorbent as well as study the CO2 sorption-desorption performance. We will modify the loaded K-based sorbent with catalyst as well as polish it with amine to improve the CO2 sorption capacity and desorption reactivity . The aerogel sorbent containing active ingredient, catalyzer and support will be synthetized with sel-gel method and dried with supercritical fluid dried method to decrease effect of gas diffusion and monodispersed will be the major CO2 sorption kinetic. The CO2 sorption-desorption kinetics, synthetics mechanism of the sorbent and the catalytic mechanism of the developed aerogel sorbent will be studied. Furthermore, the aerogel sorbent will be applied to a fixed bed reactor and investigate the deactivation mechanism of the sorbent. Finally, the theory and approach of using the aerogel potassium-based sorbent for post-combustion CO2 capture technology will be supplied and the studies above are thought to be an important prolongation for alkali-based sorbent for post-combustion CO2 capture technology.

钾基吸收剂干法捕集CO2技术具有脱碳能力强、循环利用率高、低腐蚀等优势，近年来日益受到关注。本项目发展基于钾基吸收剂的CO2捕集技术的理论和方法，发展一种结合有机和无机吸收剂优点的新型气凝胶型钾基吸收剂。为提高吸收剂的脱碳能力及降低再生能耗，对钾基吸收剂表面进行胺基修饰及催化剂添加。利用溶胶凝胶法将活性成分、催化剂成分、载体成分有机结合，以最大限度地使吸收剂的脱碳机制由多层扩散吸收发展到单层表面吸收。探明催化剂、氨基前驱物、吸收剂载体及其前驱物与碳酸钾的合成机制；揭示表面胺基修饰催化剂添加的气凝胶型钾基吸收剂的脱碳机理、再生反应机理、催化机理及吸收剂的失效机制。本项目最终形成的气凝胶型钾基吸收剂干法捕集CO2技术的理论和方法，是对已有燃烧后碱金属基干法捕集CO2技术的一个重要拓展。

钾基吸收剂干法脱除CO2技术具有循环利用率高、能耗低、无二次污染等优势，具有广阔的应用前景。项目结合燃煤电厂的特点以及该技术存在的不足，对该技术进行了系统的机理性研究。研究制备了新型气凝胶型钾基吸收剂，并对其表面特性和脱碳反应机理进行了实验研究。研究了各种因素（包括K:N摩尔比、水蒸气浓度、反应温度等）对碳酸化反应的影响规律和机制；研究了SO2、CO2与钾基吸收剂的反应特性及机理，建立了SO2和CO2的竞争反应模型；研究了SO2对胺基吸附剂脱碳特性的影响，探明了吸附剂失效的规律和机理，建立了相应的理论体系。研究探明了TiO2掺杂钾基吸收剂催化再生特性的DFT和动力学研究，降低再生反应的活化能。为更进一步提高催化效果，研究了ZrO2掺杂改性负载型钾基吸收剂的催化再生特性及再生反应动力学；为降低再生反应温度，制备了新型钾基纳米流体吸收液，并初步探究其脱碳-再生循环特性。通过本项目的研究，有效的提高了吸收剂的脱碳能力及降低再生能耗，得到了系统的基础及理论数据，是对已有燃烧后碱金属基干法捕集CO2技术的一个重要拓展。