Experimental Studies On Biomass Pyrolysis Mechanism For Bio-oil And Design Of Fluidized-bed Flash Pyrolysis Facility

The exploitation and utilization of biomass energy is an effective method for relieving the pressure of conventional energy resources shortage. The technology of biomass pyrolysis can convert low-quality biomass into bio-oil that has the character of high-quality, high energy density, cleanness and zero carbon dioxide emission. It can not only relieve the demand press of power fuel and improve the using efficiency of biomass energy in China rural area, but also can improve the structure of china energy. The research was conducted according to this purpose.On the basis of an assessment on the existing technologies of biomass pyrolysis for producing bio-oil, the experimental study on the cellulose pyrolysis behavior was carried out. The effects of the reacting temperature and residence time towards pyrolysis products were obtained. The mechanism of these two mainly parameters was also analyzed. The research results provided the foundation for further study of biomass pyrolysis mechanism in future.A mathematic model of cellulose paper pyrolysis in the mechanic reactor was proposed. The model was integrated the kinetic model of cellulose pyrolysis and transfer model of mass and heat. The porosity changing during the cellulose pyrolysis and convective mass transfer caused by pressure variations was also considered in the model. The reaction product distribution varying with the reactor temperature and reacting time was obtained. The results from model and experiment were also compared and analyzed. It was believed that the model could be used for some references to optimize the mechanic reactor.The physic-chemical properties of bio-oil produced from biomass flash pyrolysis experiments were analyzed. The influences of process parameters on bio-oil properties were investigated, and the bio-oil produced from pyrolysisof different biomass feedstock was also compared. Because of some undesired characteristics such as high oxygen content and high water content, the further upgrading of bio-oil is necessary. A quantitative pretreatment scheme suitable to GC-MS analysis of bio-oil was proposed for the first time in China, and an extensive determination of the chemical composition of bio-oil fractions was performed by means of GC-MS coupling. These studies were crucial for the upgrading and utilization of bio-oil.Using some novel designing method, which are suitable to biomass and pyrolysis characteristics, were applied in designing the fluid bed biomass flash pyrolysis system. And the designing methods of two mainly components of the system (reactor and condenser) were expatiated. The flow of three different phases (vapor, liquid, and solid phase) about the biomass pyrolysis system was described. In the last referencing some relative literatures, several utilizations of bio-oil were introduced and the prospect of bio-oil utilization was also discussed.