Research On Pyrolysising Biomass Powder For Bio-oil

Energy and environment, as the two main themes of the society at present, has become the focus of people's attention. Energy for Sustainable Development has become the most important and prominent issues all over the word. Therefore, the search for renewable energy resources and the utilization of them has become the inevitable trend of human development. The biomass, as the only storable, transportable and renewable clean energy, has occupied an important position in the energy field nowadays.The raw material used in the experiment is the biomass powder shredding from the pine wood of which most particle size is below 150μm. And we also analyse its industrial composition, elemental composition and thermal value to understand its basic chemical properties. In this dissertation, we mainly discuss the temperature distribution of the pyrolysis reactor, and analyse how the reaction temperature (400°C~600°C), biomass particle size (<450μm) and feeding rate of powder (10.5g/min~23.4g/min) affect the distribution of biomass pyrolysis product and the composition of pyrolysis gas and residue coke. We use orthogonal experiment to find out the experimental conditions to reach the best bio-oil yield and analyse the chemical composition of the bio-oil.The experimental results show that with the increasing temperature, the yield of bio-oil increases firstly and declines then, gas rises, coke declines. Small particle size of the biomass powder is conducive to the formation of bio-oil, and coarse material brings an increase in the yield of coke and un-condensational gas. The increasing of feeding rate in a certain area is conducive to increasing the yield of bio-oil. Higher temperature is conducive to the increase of CO and CH4 and the reduction of CO2 in the pyrolysis gas. The pyrolysis gas produced from the small particle size of biomass powder contains higher levels of CO and CH4, and less CO2. Higher temperature makes the volatile content of the pyrolysis residue coke decrease and ash content increase. The orthogonal experiment shows that the order of the significant impact on the yield of bio-oil is: temperature>particle size> feeding rate. Under the condition of the temperature at 500°C, biomass particle size smaller than 91μm and feeding rate at 12.5g/min, the yield of bio-oil reaches highest to 41.05% in this pyrolysis reactor. Major components of bio-oil is 1,6-Anhydro-á-D-glucopyranose (levoglucosan), representing 25.193%.