Catalytic Synthesis Of Long-chain Biofuels From Low-carbon Chain Hydrocarbons And Synthesis Gas

With the continuous development of society,the shortage of oil resources and environmental pollution have become problems that need to be solved urgently.As the only natural renewable carbon source,replacing fossil energy with biomass is one of the effective ways to solve this problem.Therefore,the production of aviation kerosene from biomass has become a recent research hotspot.This method has the advantages of low pollution and conforms to the concept of circular economy.In this paper,the impregnation method and precipitation method were used to synthesize Co-based catalysts for the preparation of biological aviation kerosene.A series of characterization methods were used to analyze the structure and physical and chemical properties of the support and the catalyst.Then,the fixed-bed reactor was used to evaluate the catalyst performance Catalytic performance.Taking CO conversion rate and C9～C15 hydrocarbon content as indicators of catalytic performance,the effects of Co loading,low-carbon chain hydrocarbon propylene added,and the introduction of additives on the performance of the catalyst were studied.the result shows:（1）As the Co load increases,the CO conversion rate increases,the relative percentage of C5～C8in the liquid product gradually increases,and the relative percentage of C9-C15 long-chain hydrocarbons decreases.And the selectivity of C5⁺hydrocarbons reaches the maximum when the loading is 10%.Considering comprehensively,the catalyst 10Co/Beta has better catalytic performance.（2）The feed rate of propylene has a significant impact on the product distribution,which can make the distribution of liquid phase products change significantly.The process conditions of the synthesis reaction were optimized,and the optimal reaction conditions were 240℃,3 MPa,hydrogen to carbon ratio of 2,and space velocity of 2.06 h^-1.（3）The active component Co particles on the surface of the catalyst after the introduction of the auxiliary agent is smaller and the dispersion is more uniform.Comparing the catalysts with different introduction sequence of active metals and additives,it can be seen that the size of the active component Co particles in the catalyst during co-impregnation is the smallest,the Co particles are more uniformly dispersed,and the CO conversion rate reaches 65.62%.This method was used to prepare catalysts with four different promoters of Ce,La,Y,and Zr.The results showed that the introduction of the promoters of Ce and Zr is more beneficial to the dispersion of Co species on the catalyst surface.And the CO conversion rate reached 62.41%and 72.26%respectively.（4）After alkali treatment of the carrier Beta molecular sieve,the CO conversion rate dropped to 54.82%,but the content of long carbon chain hydrocarbons C16～C21 in its liquid product increased to 30.03%.The catalysts 10Co/3Ce/Beta-NH4OH and 10Co/3Zr/Beta-NH4OH were prepared by the ammonia precipitation method.The results showed that the CO conversion rates were 58.24%and 56.36%,respectively.And in the liquid product distribution,not only the relative percentage of C16～C21 reached more than 25%,the content of the target product C9～C15 reached about 67%.And the catalyst can still maintain good reaction performance after 272 h.