Synthesis Of Hierarchical ZSM-5 And Its Catalytic Hydroconversion Of Vegetable Oil To Produce Alernative Fuel

In recent years,the use of traditional fossil fuels has raised a series of environmental and energy problems.Now it has become a new research hotspot to seek new renewable alternative fuels.Hydroconversion of vegetable oil to synthetic alternative fuel has received extensive attention.Developing a high-performance catalyst is still a challenge for this process.In this work,we designed and synthesized a bifunctional template,and the hierarchical ZSM-5 zeolited was prepared using this new template through hydrothermal method to explore the effects of the acid sites,pore structure and the active metals location on the hydrodeoxygenation process of vegetable oil.Firstly,the bifunctional template of carbon nanotubes grafted with quaternary ammonium salt was successfully synthesized.The influences of feeding ratio,properties of carbon nanotubes and quaternary ammonium salt on the graft content of quaternary ammonium salt were investigated.Combined with the characterization of thermogravimetric and infrared,a controllable grafting method was developed.Secondly,the hierarchical ZSM-5 zeolite was prepared using the as-synthesized bifunctional templates through hydrothermal method.The influences of the quaternary ammonium salt content in bifunctional templates and the Si/Al ratio on pore structure and acidity of the hierarchical ZSM-5 were studied.The results showed that the obtained hierarchical ZSM-5 zeolites using high grafting templates had smaller crystal size,higher HF index and acidity as well as Br?nsted acid.The morphology of the ZSM-5 zeolite with low Si/Al ratio was much close to spherical.Finally,the hierarchical ZSM-5 supporting different metals was evaluated in the hydroconversion of soybean oil to hydrocarbons.The influcences of quaternary ammonium salt content in bifunctional templates,Si/Al ratio,metals and active metal location on the hydrodeoxygenation process of soybean oil were investigated.The results showed that high selectivities of C₉-C₁₅ hydrocarbons and aromatic were obtained on the catalyst prepared using the bifunctional templates of high quaternary ammonium salt content.The cracking reaction was enhanced by the acid sites and pore structure.The Pt/ZSM-5 catalyst showed higher activity that Pt@ZSM-5catalyst.The active metal NiMo had higher catalytic deoxygenation activity than Pt,and the 62.5%selectivity of C₉-C₁₅ hydrocarbons was achieved.