钙基载体协同催化焦油制氢与碳捕获机理及循环性能研究

The technology of Ca-based chemical looping gasification can produce hydrogen-rich gas as well as capture CO2, has become the research highlights in zero discharge system. However, the main problems to limit its industrial application are: refractory tar and deactivated of the carrier. In view of the above problems, a modified Ca-based carrier, good reactivity and good cycle performance, which can as a tar reforming catalyst and CO2 capture will be prepared. Early researches had indicated that, NiO on modified dolomite catalyst has shown good removal effect on tar and CO2. However, the reaction activity and cycle performance of catalyst has declined obviously after a long time running. Therefore, the main study points are: adding inert materials reinforced skeleton and doping metal elements to optimize the preparation methods, the process parameters and reaction performance; seeking the path of synergistic catalytic tar and CO2 capture and its thermodynamics and kinetics mechanism by theoretical simulation and experimental study to investigate the coordination mechanism of Ca-based carrier during the biomass chemical looping gasification process; studying the microstructure evolution regularity of reactants and products during the synergy catalytic and cyclic calcination/carbonation reaction process by TGA and fluidization experiments, in order to investigate the cycle stability and deactivation mechanism of Ca-based carrier. The research results can provide important basic data and theoretical support for the development of biomass chemical looping gasification.

基于钙基载体的生物质化学链气化技术能同时制备高浓度H2和捕获CO2，成为各零排放系统方向的研究热点，限制其工业化应用的主要问题是：焦油难降解、载体易失活。针对以上问题，本项目提出制备具有良好反应活性、循环性能的协同催化焦油和碳捕获功能的钙基载体。前期研究表明，改性白云石载镍催化剂表现出良好的焦油和CO2去除效果，但长期运行后其反应活性和循环性能有明显下降。本研究在此基础上，通过添加惰性材料增强骨架和掺杂金属元素进一步优化制备方法、工艺参数和反应性能；通过理论模拟和实验研究，探寻生物质化学链气化过程中该钙基载体协同催化焦油与碳捕获的途径及热力学、动力学机制，揭示其在化学链气化过程中的协同机理；通过TGA、流态化实验，分析协同催化与循环煅烧/碳酸化反应过程中反应物及产物的微观结构演变规律，揭示钙基载体的循环稳定性能及失活机理；本研究将为生物质化学链气化技术的发展提供重要基础数据和理论支撑。

针对生物质热化学制氢过程中不可避免的会产生焦油和较高浓度的CO2，影响能源回收效率和气体热值，本项目开展了基于钙基载体协同生物质焦油催化与碳捕获的研究。主要开展了以下工作并取得了一系列成果：制备了系列钙基载体和生物炭负载活性金属载体，开展了钙基载体协同焦油催化与CO2捕获热力学与动力学研究，揭示了钙基载体对生物质催化热解与碳捕获的反应特性；探讨了碱金属K+Ca协同催化生物质焦油与CO2捕获的反应机理，并从含氧官能团演变的角度揭示了其对三相产物影响的机理，提出了相应的反应路径关系； 在自行设计的反应器基础上，开展了C12A7、Ca-C12A7、NiO/Ca- C12A7以及Ni/char、Fe/char催化载体对生物质热解/气化的反应特性研究，并结合反应前后载体的微观结构特性对反应机理进行分析，提出了相应的焦油催化反应和CO2捕获机理，并提出了一套新的工艺路线图。此外对上述载体的稳定性能进行了研究。本项目的研究为基于钙基载体的协同生物质焦油催化转化与碳捕获技术提供理论指导和数据支持，有望促进高效低碳能源技术的发展。