Preparation And Performance Of Hydrodeoxygenation Catalyst Based On High Specific Surface Silicon Carbide Carrier

Biomass is a renewable energy source with huge reserves and a wide range of sources.Large amounts of water vapor and catalyst poisons are often present in industrial reactions that convert biomass feedstocks into fuels and high value-added products.Therefore,the stability of the catalyst is required to be very high in the above reaction.However,silicon carbide,as an excellent ceramic material,has been proved to have great development potential as a catalyst carrier with high stability,and has been applied in the industrial reaction process of gas phase.The high specific surface area carrier can improve the stability of the catalyst,the dispersion of the supported metal and the catalytic activity of the catalyst in high temperature and strong exothermic reactions.Therefore,this paper is based on the preparation of high specific surface area silicon carbide and uses it as a catalyst carrier to synthesize palladium and ruthenium catalysts,and the following research results are obtained:(1)The preparation method is mainly based on the sol-gel method.On the basis of this method,it is innovatively proposed to use activated carbon particles as one of the raw materials,and the conditions of the preliminary hydrolysis reaction are set to an alkaline environment.Finally,three kinds ofβ-Si C with good purity,good crystallinity and cubic crystal were obtained.The specific surface area ranges from 30 to 600 m~2/g,respectively.It has various morphological characteristics such as carbon nanowires,particles and worms.(2)Four kinds of silicon carbide materials were used as catalyst carriers to support Pd and Ru elements with different contents.The stability tests of the palladium catalysts prepared by the four supports were carried out in two hydrothermal environments of boiling and steam,and it was found that the catalyst with b-Si C as the support had the best hydrothermal stability.In the two hydrothermal environments,the catalyst has no agglomeration phenomenon at different test times,and has good crystal structure and crystallinity.(3)Finally,in the hydrodeoxygenation reaction of dimethylfuran trimerization products,we found that when the Pd loading was 5wt%,the conversion rate of raw materials could reach more than 98%.The Pd/b-Si C catalyst has the best catalytic performance and stability by comparison.Subsequently,in the pyrolysis reaction of lignin in beech wood,it was found that more than 30wt%solids recovery and more than90wt%bio-oil yield could be obtained under the catalysis of Ru/Si C.In addition,the ruthenium catalysts prepared with a-sic and b-sic as carriers can obtain more than 98%bio-oil yield and more lignin monomer structure when the Ru loading capacity is 1wt%,and the selectivity of lignin monomer is more than 20%.