天然气在我国未来的能源体系中占有重要的地位.以生物质为原料,将合成气通过甲烷化反应转化为天然气是将生物质能源转化为富氢、低碳能源的有效途径.本文概述了生物质合成气甲烷化催化剂的研究进展,重点阐述了CO和CO2甲烷化催化剂不同的活性组分(Ni,Co,Ru等)对甲烷化反应催化效果的影响,以及不同结构的催化剂载体(Al2O3,ZrO2,TiO2,SiO2等)对催化剂活性组分的分散程度和粒径大小的影响;分析了添加不同类型的助剂(MgO,La2O3,CeO2等)以及不同的制备方法(浸渍法,共沉淀法,溶胶凝胶法等)对催化剂的催化效果的影响,介绍了一些新型的催化剂载体和催化剂制备方法的特点,并指出现有甲烷化催化剂的研究目标和存在的主要问题.理想的甲烷化催化剂应当具有良好的低温催化活性和高温稳定性,具有良好的活性组分分散度和较小的粒径,同时具有良好的抗积碳性能.然而,甲烷化反应释放大量的热量导致催化剂活性组分迁移烧结,并在活性位点上积碳,从而致使催化剂钝化失活.因此,应当通过开发双金属或多金属催化剂,改进或开发具有良好孔隙结构和表面积的催化剂载体,添加不同功能的结构助剂或电子助剂,改进催化剂的制备方法等手段提高甲烷化催化剂活性组分的分散度,降低活性组分的粒径,从而提高甲烷化催化剂的催化活性,热稳定性和抗积碳性能.认为应对CO和CO2的甲烷化反应机理,新型复合载体的制备工艺,活性组分与助剂和载体的相互作用机理,催化剂的失活机理和可再生性能等方面进行深入的研究,并以此为基础开发设计具有高催化性能的甲烷化催化剂.%Natural gas occupies an important position in China's future energy system. The conversion of syngas to natural gas via methanation is a useful way to convert biomass energy into hydrogen-rich and low-carbon energy by using biomass as raw material. In this paper, the progress of methanation catalysts of bio-syngas was summarized. The effects of different active components (Ni, Co, Ru, etc.) on the catalytic performance of CO and CO2 methanation catalysts were discussed, and the effects of catalyst carriers with different structures (Al2O3, ZrO2, TiO2, SiO2, etc.) which can provide different dispersion degrees and particle sizes of the active components were expounded. The effects of different types of additives (MgO,La2O3,CeO2,etc.) and different preparation methods (Impregnation, Coprecipitation, Sol-gel method, etc.)on the catalytic performance of the catalyst were analyzed. This paper also introduced some new types of catalyst carriers and the characteristics of catalyst preparation methods, and pointed out the research targets and the main problems of the existing methanation catalysts. The ideal methanation catalysts should have good catalytic activity at low reaction temperature and good stability at high reaction temperature, with good active components dispersion and smaller particle size, and have good resistance to carbon deposition. However, the methanation reaction releases a large amount of heat, which leads to the removal and aggregation of the active components on the catalyst and carbon deposition on the active site surface, resulting in the deactivation of the catalyst. Therefore, it is necessary to improve the performance of the methanation catalysts by developing bimetallic or polymetallic catalysts, improving or developing catalyst carriers with good pore structure and surface area, adding different functional structural additives or electronic additives, improving the preparation methods of the catalyst or other means, to increase the dispersion and decrease the particle size of the active component, and finally improve the catalytic activity, thermal stability and carbon deposition resistance of the methanation catalysts. It is believed that the mechanism of CO and CO2 methanation reaction, the preparation process of new composite carriers, the interaction mechanism between active component and additives or carriers, the deactivation mechanism of catalyst and the regeneration performance should be studied in depth, and the catalysts with high catalytic performance should be designed and developed.
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