The Research On The Thermochemical Liquefaction Of Biomass In Water

Biomass is a one and only renewable organic resource, and it has been focused on as an alternative energy for fossil fuels. It can transform into bio-oil, hydrogen and other clean energy sources by thermochemical conversion using hot-compressed water. And this is a reason why many researchers have investigated this biomass conversion method.In this research, we made study on biomass convert in super(sub)critical water, and the water was used as a reaction medium. Then we did the exploring experiment used straw as raw material, and researched the effect of different reaction condition in the process of biomass thermochemical liquefaction, especially on the yield of bio-oil, gas and solid residue. The bio-oil and solid residue in our research were analyzed. We also researched the influence of alkali catalyst, and the main experimental apparatus is an autoclave.The yield of bio-oil is determined by materials and reaction conditions. The experiment revealed influence of temperature, resistant time, heating rate and pressure to the yield of bio-oil. The result showed the best temperature and resistant time is 380- 400℃and 15min, respectively. Increasing the pressure increased the yield, but at low pressure, the pressure made evidently effect to the experiment. The yield increases with an increase in heating rate, however, the higher heating rate, the more energy consumed, so the best heating rate is 12℃/min. The materials of our experiments also influenced the yield, because the concentration of lignin adversely effect to the yield of bio-oil.The bio-oil which produced by our experiment is a black ropy liquid, and has complex component, include ketone substance and hydroxybenzene substance, the comparatively molecular weight and carbon number is around 96-276 and 6-19, respectively. And it has strong acidity and high oxygen content. It can't use for fuel directly, however, the energy density of our bio-oil has really advanced, compared to the raw material, so it still had a development foreground.The experiments also review three kinds of alkali catalyst, Na2CO3,K2CO3 and KOH, influence of the biomass liquefaction. The result showed alkali catalyst could increase the yield of bio-oil, induce the N content, and increase the H/C and O/C. Compare the three kinds of catalyze experiments, the result revealed Na2CO3 has best...