煤制天然气甲烷化催化剂及机理的研究进展

煤制天然气技术是将高碳能源转化为富氢、低碳能源的有效途径，发展以煤为原料、将合成气通过甲烷化反应制备天然气是今后煤清洁利用的重要途径。介绍了国内外煤制天然气的研究现状和甲烷化反应在煤制天然气中的应用。阐述了近年来CO、CO₂甲烷化催化剂中几种常见的氧化物负载型Ni基催化剂载体(Al₂O₃、ZrO₂、SiO₂、TiO₂)和催化剂助剂的制备方法以及化学结构特点，分析了一些新型催化剂载体（MWCNT、SiC、LaFeO₃）、贵金属催化剂、非晶态合金催化剂、钙钛矿催化剂的研究现状和制备方法对催化剂催化性能的影响。分别对因高温烧结、催化剂中毒和催化剂积炭在工业上引起的甲烷化催化剂失活进行分析，并提出催化剂的改进方法。阐述CO甲烷化反应的次甲基机理、表面碳机理和变换-甲院化反应机理；近年来CO₂甲烷化反应机理尽管一直存在分歧，但在催化过程中生成含碳中间物种的理论已被认同。今后甲烷化催化剂的研究方向包括开发新型甲烷化催化剂（低温催化剂、催化剂掺杂改性）、新型复合载体、抗硫催化剂（钼、钨催化剂）以及开发甲烷化新工艺和进一步深入探索甲烷化反应机理。

Research advance in methanation catalysts for synthetic natural gas and their catalytic mechanisms

The technology of synthetic nature gas （SNG） is an effective way for the conversion of high- carbon energy to rich-hydrogen and low-carbon energy. It is an important way of clean utilization of coal that natural gas is prepared from synthesis gas via methanation reaction by using coal as the raw material in future. In this paper,the research status of SNG at home and abroad and the application of methanation reaction in SNG were introduced. The preparation methods and the chemical structural characteristics of the common carriers for supported oxides Ni-based catalyst, such as A12 03, ZrO2, SiO2 and TiO2, and the catalyst additives in methanation catalysts for CO and CO2 were expounded. The research status of the novel catalyst carriers （MWCNT, SiC and LaFeO3 ）, noble metal catalysts, amorphous alloy catalysts andperovskite catalysts, and the effects of their preparation methods on the catalyst performance were dis- cussed. The reasons of catalyst deactivation due to high-temperature sintering, catalyst poisoning and coke deposit were analyzed and the improvement methods of the commercial catalysts for methanation were put forward. The mechanisms of the methylene, the surface carbon and the shift-methanation for CO methana- tion were described,respectively. There existed various differences among the reaction mechanisms for COz methanation in recent years, but the theory that carbon containing intermediate species were generated in the catalytic process was recognized. The research directions for methanation catalysts in future, including the development of new methanation catalysts （low temperature catalyst, catalyst doping and modification）, new composite carriers, anti-sulfur catalysts （ molybdenum, and tungsten based catalysts）, development of the new methanation process and the further research on methanation mechanism,were out lined.