The Preparation Of Iron-based Molecular Sieve Catalyst By Solvent-free Method And Its Fischer-Tropsch Synthesis Performanc

Fischer Tropsch synthesis reaction was first invented by German scientists Fischer and Tropsch in 1923.This kind of reaction can convert carbon resources such as coal,natural gas and biomass into liquid fuels such as gasoline,ethanol and methanol.It is also considered as the most potential way to convert non oil based carbon resources into liquid fuels.China's oil and natural gas reserves are scarce,but coal resources are relatively rich.They have a wide range of sources,large reserves,large demand,but they are difficult to make full use of,and even cause a lot of energy waste.To produce CO/H₂ syngas from carbon resources such as coal and biomass,and then to convert them into hydrocarbons is one of the effective ways for the rational utilization of coal resources in China,and it also adapts to the current situation of rich coal,poor oil and little gas in China.However,the product distribution of Fischer Tropsch synthesis follows Anderson schlulz Flory?ASF?rule,and it is difficult to synthesize distillates with a specific carbon number range.How to break this rule is the focus of people's research.At present,people break this rule mainly through two aspects of catalyst modification and process strengthening.By promoting the secondary reaction,the product concentration and distribution can be controlled.Therefore,this paper focuses on the development of a new type of catalyst for Fischer Tropsch synthesis,which is beneficial to the formation of gasoline fractions and isoparaffins.The influence of pore structure,morphology,acidity and metal position on the distribution of Fischer-Tropsch synthesis products is analyzed by XRD,BET,SEM,TEM,TPR,TPD and other characterization methods.?1?ZSM-5 zeolite was prepared by solvent-free method,and Zn/Si O₂ and Fe/Si O₂ catalysts were prepared by combined impregnation method.The second reaction of each catalyst to the product of the last reaction is used to obtain the target product through the optimization and regulation of the second reaction.?2?The catalyst?NaFe@ZSM-5?coated with NaFe particles was prepared by solvent-free synthesis.With the increase of NaFe loading,the pore structure and surface properties of the catalyst changed.FT-IR results showed that co MPared with the physical mixed catalyst,the embedded catalyst significantly reduced the Si-OH group on the zeolite surface,and effectively inhibited the reaction site of WGSR to generate CO₂.The selectivity of 15%NaFe @ ZSM-5 is 30.7% for isoparaffins,13.1%for CO₂ and 10% for CH4??3?Silicalite-1,ZSM-5,and heteroatom molecular sieves?Mg S1?with MFI topological structure were synthesized by solvent-free method.Fe and Al supported zeolite catalysts were prepared by combined impregnation method,and the catalytic performance of heteroatom zeolite in Fischer-Tropsch synthesis was studied.The results showed that the pore structure,active center and acid center of the modified catalyst changed obviously.The selectivity of gasoline on 10% Al-Fe/S1 catalyst is as high as 70.9%,and the selectivity of CH4 and CO₂ is the lowest,which are 6.2% and12.0%,respectively.Fe/ZSM-5 catalyst showed high gasoline and isomerization selectivity of 70.4% and 48.1%,respectively.In addition,the results of Fe/Mg S1 catalyst showed that the product distribution shifted from C5-C11 to C₂-C₄,and the selectivity of C₂-C₄ was 40.6%.