Method for preparing biomass liquefied oil by biomass catalytic liquefaction

The invention discloses a method for preparing biomass liquefied oil by the catalytic liquefaction of the biomass, and relates to a method for preparing the bio-oil by the liquefaction of the biomass, which belongs to the field of chemical and industrial catalysis. The method for preparing the bio-oil comprises the steps as follows: arranging the biomass, solid acid and an aqueous solution containing C1-C3 monobasic alcohol in a pressure vessel; stirring and heating up the mixture to the temperature of 200 to 280 DEG C, with the pressure of 2 and 7MPa and the time of 0.5 to 10 hours; then cooling down the mixture to normal temperature and filtering the mixture; using C1-C3 halohydrocarbon to carry out extraction and refining to the obtained filtrate and filter residues respectively; combining the extracting and refining liquid and removing the halohydrocarbon and alcohol to prepare the biomass liquefied oil. Used independently as a technique for biological energy conversion, and with moderate conditions and yield as high as about 65 percent, the method is free from the discharging of alkaline solution and salt solution in the production process, thus laying the foundation for the industrial and clean utilization of the biomass.