Study On Ni-based Methanation Catalyst For Coal Natural Gas

Natural gas is an energy source with low carbon content,no pollution,and high calorific value.The use of coal as a raw material to produce natural gas has filled the problem of insufficient gas supply in China.In coal-to-gas technology,the key is methanation catalysts.The development of methanation catalysts with high temperature resistance and good catalytic activity is of great significance to the development of China's coal-to-gas technology and the rational use of resources and environmental protection.On the one hand,the catalyst was explored and improved in the preparation process,including the preparation of pure Al2O3,ZrO2-Al2O3 and MgO-Al2O3 catalyst supports.The catalysts were selected by impregnation and coprecipitation.The effects of the amount and ratio of the additives La2O3 and Ce2O3 and the content of the active component Ni on the performance of the catalyst were investigated.Through the exploration of the above factors,several catalyst samples with different composition,ratio and loading process were prepared.The activity of the catalyst was tested by a micro-fixed bed reactor and characterized by X-ray diffraction(XRD),specific surface area measurement(BET)and scanning electron microscopy(SEM).The preferred catalyst sample composition is 50%Ni-4%La2O3-MgO/Al2O3.On the other hand,the optimized catalyst is used as a sample for the catalytic reaction,and the process conditions of the catalytic reaction are optimized.The reduction conditions,reaction space velocity and reaction pressure of the catalytic reaction were screened to obtain suitable reduction conditions for the catalyst.The continuous stability test shows that the catalyst can achieve more than 99%CO conversion and CH4 selectivity in the middle and low temperature range(300-400?),and the CH4 selectivity in the high temperature range(500-700?)can be maintained at 70%.Left and right,with good high temperature resistance and excellent wide temperature applicability.