In Suit Catalytic Online Upgrading Of The Bio-oil Over La/MCM-41 Combined With HZSM-5

Biomass energy is a renewable resource that can be converted into liquid fuel to replace fossil fuels.The fast pyrolysis is a promising technology which used in the field of pyrolysis because of high efficiency and easy operation.However,due to the poor quality,the bio-oil is hard for its direct application as a power fuel.Therefore,it is significant to improve the quality of bio-oil.Zeolite molecular sieve is common catalyst for upgrading of bio-oil.In this work,the rape straw was choose as biomass material,the modified of La/MCM-41 and HZSM-5molecular sieve were used as catalysts and employed in the catalytic upgrading of pyrolysis vapor to obtain high valued bio-oil in a fix bed reactor.The specific research works are as follows:?1?La/MCM-41 catalysts with different La loading mass fractions were prepared and used in the catalytic upgrading of pyrolysis vapors from vacuum pyrolysis of rape straw to obtain high-value bio-oil.MCM-41 zeolite before and after the La loading was characterized in detail by XRD,SEM,TEM and Py-IR,respectively.The influence of La loading on the composition and properties of organic phase of bio-oil was analyzed,and thermogravimetric analysis was performed on the four deactivated catalysts after used 120 min.The results show that La/MCM-41 had better ordered structure,the content of Bronsted acid sites and Lewis acid sites on the surface of La/MCM-41 increased.The physical and chemical properties of bio-oil were improve effectively by La/MCM-41,and the pH value and calorific value were obviously improved.The highest hydrocarbon content?34.59%?was obtained at a La loading of 5%,and mainly with monocyclic aromatics hydrocarbons,the content of oxygen in oxygenated compounds is further reduced.Simultaneously,the coke content of the catalyst decreased further,which exhibited good anti-coking performance.?2?5%La modified MCM-41 combined with HZSM-5 molecular sieve were carried out in catalytic upgrading of pyrolysis vapor.Combining the advantages of the catalysts,the ratio of two catalysts are 1:1,modified and combined catalytic mode?La/MCM-41+HZSM-5?,combined catalytic?MCM 41+HZSM-5?and single catalytic?La/MCM-41,HZSM-5?were compared in this paper.The composition of the bio-oil organic phase was analyzed for different catalytic ways.The results showed that the bio-oil gas phase achieves a higher yield rate to48.72%,the heating value of organic phase was up to 36.69 MJ·kg^-1 and the content of hydrocarbon increases significantly to 45.41%and mainly with monocyclic aromatics hydrocarbons.The compositions of bio-oil organic phase obtained by different catalysts were contained alcohols,phenols,carboxylic acids,ether lipids,hydrocarbons and other substances.?3?The coke type,weight loss rate and anti-coking property of each group of deactivated catalyst samples were analyzed under modified combined catalytic mode.The results showed that the deactivated HZSM-5 zeolite in each group had two high-temperature weight loss peaks,which indicated that the coke deposited on the surface were mainly the coke I and coke II,the content of coke I was higher and the content of coke II was lower.It could be observed from the deactivated MCM-41 zeolite in each group that there was one weight loss peaks,the coke composition was single,which indicated that the coke deposited on the surface was mainly coke I within the temperature range of 400⁵00°C.When La/MCM-41+HZSM-5 was used,the two molecular sieves had lower total weight loss,coke deposited on the surface decreased further,which showed a better performance of coking resistance.