Optimization,Design And Performance Of Catalysts For Synthesis Gas To Lower Alcohols And Tail Gas Methane And Carbon Dioxide Reforming

The one-step catalytic conversion of syngas to low-carbon alcohols and the recycling of methane and carbon dioxidein the tail gas is an important way to cleanly convert and efficiently utilize coal and biomass resources,and is of great significance to achieve carbon peaking and carbon neutrality.KMS catalyst is a new type of molybdenum-sulfur-based catalyst developed in our laboratory.It has excellent CO conversion and isobutanol selectivity in the synthesis gas to lower alcohol reaction,but its engineering scale-up needs to consider the addition of catalyst forming aids and the effect on catalytic performance.The main components of the tail gas of the synthesis gas to lower alcohol reaction with KMS as a catalyst are methane and carbon dioxidecontaining a small amount of sulfur.The synthesis gas is prepared by the reforming reaction,and the realization of the recycling of the tail gas is of great significance to reduce the carbon emission in the reaction process.Non-precious metal nickel-based catalysts have the advantages of high activity and low cost and are widely used in methane carbon dioxidereforming reactions,but the catalysts are prone to carbon deposition,sintering and sulfur poisoning and lose their activity.In this paper,preliminary exploration work is carried out from the perspective of optimizing the performance of the catalyst in the reaction system and expanding the function of the catalyst.On the basis of the previous work in our laboratory,the effect of add molding additives on the catalytic performance of KMS catalyst for the synthesis gas to lower alcohol reaction was investigated to providebasic data for catalyst molding.Design and prepare new nickel-based reforming catalysts from the perspective of the dispersion,stabilization and sulfur resistance of active components by carriers and preparation methods,explore the preparation methods and processes of catalysts,study the catalytic performance of new catalysts,and providebasic data for exhaust gas recycling.The specific research contents are as follows:（1）Using K-montmorillonite after replacing Ca²⁺in montmorillonite with potassium acetate as the carrier and KMS as the active component,the supported catalyst X%-KMS/M was prepared by the equal volume impregnation method,and the catalyst synthesis gas to lower alcohol was investigated.catalytic performance.The results showed that the catalytic activity of KMS was the best at the reaction temperature of 390°C,with a CO conversion rate of 56.0%,a total alcohol selectivity of 48.6%,a C₂₊alcohol selectivity of 94.0%,and an isobutanol selectivity of 26.0%.Consistent with the results of previous studies.Compared with KMS,the CO conversion,total alcohol selectivity,C₂₊alcohol selectivity and isobutanol selectivity of X%-KMS/M catalyst decreased,but the catalytic performance also improved with the increase of loading.K-bentonite as a carrier will play a role in dispersing KMS,but low loading will reduce the original catalytic performance of KMS.K-bentonite can be used as a forming binder for KMS catalysts.The research results providebasic data for the next catalyst forming experiments.（2）Using carbon nanotubes（CNTs）and graphene（GO）as additives,the catalysts CNTs/KMS and GO/KMS were prepared by mechanical mixing with KMS,respectively.The catalytic performance of the catalysts for synthesis gas to lower alcohols was investigated.The results showed that the CO conversion,C₂₊alcohol selectivity and isobutanol selectivity of the CNTs/KMS catalyst decreased to varying degrees.The CO conversion rate,total alcohol selectivity,and C₂₊alcohol selectivity of the GO/KMS catalyst were compared with those of KMS.Basically no change.The two carbon additives did not significantly improve the catalytic performance of KMS,which may be related to the way of adding the additives,but graphene is suitable as a molding lubricant for KMS catalysts.（3）Using coal gangue（CG）and desulfurized coal gangue（CG-deS）as the carrier,Ni as the active component,the supported catalysts Ni/CG and Ni/CG-deS were prepared by the equal volume impregnation method.Catalytic performance of the catalyst in the methane carbon dioxidereforming reaction at a temperature of800°C.The results show that Ni/CG-deS exhibits the best catalytic activity,the conversion rate of CH₄ and CO₂ reaches 90%,and the reaction is not deactivated for100 h,which provides a new idea for the design of reforming catalysts.（4）The Ni/CG-deS catalyst was further optimized by low-temperature thermal plasma method（Pla）,and new nickel-based catalysts Ni/CG-deS-Pla and Ni-pre/CG-deS-Pla were prepared.Catalytic performance of the catalyst for methane carbon dioxidereforming reaction at 800°C.The results show that the average particle size of Ni particles,the active component of Ni/CG-deS-Pla,is 50.87 nm,and the CH₄and CO₂ conversions are 51%and 64%,respectively,after 100 h of reaction,and still maintain an upward trend.The average particle size of Ni particles of Ni-pre/CG-deS-Pla was 8.37 nm,and the CH₄ and CO₂ conversions were 29%and 39%,respectively,after 100 h of reaction,and still maintained an upward trend.The preparation method provides a new idea for the preparation of methane and carbon dioxidereforming catalysts.However,the catalytic performance does not increase but decreases compared with that before optimization,and needs further improvement.