Research On Catalysts For Syngas Fluidized Bed Methanation

China's energy status is rich in coal resources,but petroleum and natural gas resources are scarce.With the continuous and rapid growth of China's economy and the acceleration of urbanization process,leading to the rapid growth of China's natural gas consumption and production and a serious imbalance in the supply and demand of natural gas.This situation determines that coal to oil and natural gas are the long-term goals for the energy security and the development of economy in China.The importance of environmental protection in recent years has influenced the energy consumption structure in China.As a typical coal based alternative energy strategy,coal to natural gas has the advantages of short route,high energy efficiency and low energy consumption in the process.It is of great significance to develop high efficiency,low carbon and clean coal resources.Synthesis gas methanation reaction is the core reaction step in the process of coal to natural gas.In this paper,the catalytic cracking catalysts(FCC)after industrial production were etched at different temperatures using different concentrations of sulfuric acid.Then the CaO were modified for the etched supports.Finally,the active components Ni or Ni/Fe were impregnated in the modified supports,and the catalysts which are suitable for syngas methanation were obtained.The influence of different preparation conditions(preparation method and calcination temperature)on the catalysts were also investigated in this paper.In this paper,the activitives of the catalysts were tested under different reaction conditions by using micro-reaction-equipment.The catalysts were characterized by BET,XRD,XRF,SEM,TEM,H2-TPR and TG.The final conclusions are as follows:Through the investigation of different etching conditions of industrial FCC catalysts,it is found that when the volume concentration of sulfuric acid solution is 50%and the etching tenperature is 50?,the obtained support of FCC-50V-50 has the better structure and properties.Through CaO modification and NiO load of the etched supports,we found that CaO modification can improve the alkalinity of the catalysts,which can reduce the particle size of NiO and increase the dispersion of active component Ni,and the catalyst of 10Ni-4Ca-F450 has the best methanation performance.Based on the test and investigation of stability,reproducibility and wear resistance,the preparation of catalysts were suitable for the methanation reaction of syngas.Through the investigation of the preparation conditions of the catalysts,it is found that the performance of the catalyst prepared by step by step method is better than that of one step method.The best calcination temperature of the catalysts is 450OC,and the relatively low calcination temperature is beneficial to the formation of smaller particle size of NiO nanoparticles.Through the preparation of the Ni-Fe bimetallic catalysts,we found that the addition of appropriate amount of Fe can significantly improve the surface area and the low temperature catalytic activity of the catalyst.The better catalytic performance of a bimetallic catalyst with a proper proportion of Ni-Fe is due to the synergistic effect between the Ni/Fe complexes.Through the investigation of the methanation conditions of syngas,we found that the suitable reaction pressure can give full play to the activity of the catalyst.Increasing the pressure is beneficial to the CO methanation reaction.Thermodynamic analysis of methanation and the three stage methanation process denoted as "fluidized bed-fluidized bed-fixed bed" were preliminarily simulated by Aspen plus software,which proved the feasibility of the process.