Study On Catalytic Liquefaction Of Agricultural And Forestry Biomass

With the rapid development of economy and shortage of fossil energy, human society is facing new challenge. The traditional energy development method-- high-pollution, high consumption of predatory will trigger the crisis in traditional energy. In order to get rid of the constraints of traditional sources of energy to economic development, seeking new and clean energy sources is broad imperative. Liquefaction of biomass can not only get a high calorific value of liquid fuel, but also extract high valuable chemicals through refining, so governments and research institutions pay more attention to the research and utilization of biomass. In this paper, the common agricultural waste rice straw and wood chips were used as reaction raw material, 1L autoclave were used as the main experimental device, the effects of the kind of raw material, temperature, catalyst and solvent type on biomass liquefaction were studied.In this study, HZSM-5 andγ-Al2O3 was used as the carrier prepared by using ion-exchange modified metal catalysts. Three methods were used in order to study the character of metal-modified catalysts. The results showed that the ion-exchange effect was good.In this work, solid and liquid products were recovered with three solvents, and four kinds of different oil was obtained. The influence of reaction temperature and catalysts on production rate and composition of the bio-oil was investigated. The influence of reaction temperature on liquefaction effect of the bio-oil was investigated between the temperature 260℃and 320℃, the results showed that the bio-oil yield increased as temperature increases, and then the yield was receded obviously with temperature kept up increasing. Rice straw can be liquefied at low temperature conditions, and the bio-oil yield was much more than wood. The influence of different catalyst which was modified by metal ions was studied, Fe3+-exchanged HZSM-5 zeolite catalyst showed the best catalytic effect, it could make the bio-oil production rate improve greatly, and the proportion of the main compound butylated hydroxy toluene increase markedly reaching more than 50%. It was also proved that metal-modified catalyst had little effect on the liquefaction of rice straw.The influence of four different alkaline catalyst on rice straw liquefaction was studied. The reaction solvent was ethanol and water mixed, solid and liquid products were recovered with tetrahydrofuran. The results showed that the bio-oil yield was solvent of water and alkaline. Water-soluble hydrocarbon content in bio-oil can be improved by alkaline catalyst. Rice straw is suitable for producing fuel as it has higher yield of bio-oil by liquefaction. Sawdust is suitable for extracting high added value chemical products by refining liquefied product.