The Research On Hydro-liquefaction Of Agricultural Biomass With Catalyst

With the development of society, more and more energy are required, but the reserves of fossil resources are limited. That posed a challenge to the survival of mankind. So search for new energy development is urgent. As a renewable resource, biomass has been focused on as an alternative energy source of fossil fuels. It is rich in resources, low-pollution and wide distribution. Biomass energy came from photosynthesis which including wood, wood waste, straw and crop by-products, municipal solid waste, as well as animals and plants, algae food processing waste generated, and so on. Several thermo-chemical processes, such as gasification, liquefaction, and pyrolysis, can be used to convert this kind of resource to bio-fuel. Hydro-liquefaction was actualized with more moderate conditions by atmospheric pressure or slightly. As the production of liquefaction had high-qualities, more and more scholars'attention wree attracted.In this work, direct liquefaction of sawdust and straw in water was performed at 260³80℃for 10 min with and without catalysts. The catalysts used in this research were Ni, Fe ion-exchanging HZSM-5 zeolite catalysts and alkaline, respectively. The objective of the study is to investigate the effect of the catalyst and different reaction condition in the process of biomass low temperature hydrothermal treatment, especially on the yield of bio-oil and solid residue. The bio-oil and solid residue in our research were analyzed.The yield of bio-oil is determined by materials and reaction conditions. The results illuminated that the experiment was impacted obviously by the catalyst. Without any of the catalyst the best temperature is 300-320℃. The bio-oil yield increased as the temperature increases, but the yield was receded obviously with temperature kept up increasing.Taking into account the biomass hydro-liquefaction with catalyst, the bio-oil yield was increased by the addition of ion-exchanging HZSM-5 zeolites catalyst, and the residue was reduced directly. The effect was more distinctly when the NiHZSM-5 was used as a catalyst. By adding NiHZSM-5 the total liquefaction yield of sawdust enhanced from 20.69% to 31.36%, moreover, the organic dissolved took 93.92% of the increased part. It is means that NiHZSM-5 catalyst promoted selectively during the hydro-liquefaction of biomass process. As the straw liquefaction with the presence of ion-exchanging HZSM-5 zeolite catalysts and alkaline catalyst, the total liquefaction yield was increased clearly. The solid residues were significantly inhibited by the catalyst, and its yield was reduced in a large degree. When Na₂CO₃, NaOH, K₂CO₃ and KOH act as the catalyst, the yield of the solid residue was extremely decreased as well as the ratio of H/C is increased obviously. The results show that NaOH has the best effect among the four of the tested alkaline catalyst.The bio-oil which produced by our experiment is a black ropy liquid, and has complex component, include ketone substance and hydroxybenzene substance. And it has strong acidity and high oxygen content. It can't be used as fuel directly,however, the energy density of our bio-oil has really advanced, The bio-fuel produced with catalyst has lower oxygen content, so its till had a development foreground.