Study On Pyrolysis Mechanism Characteristic And Pyrolysis Kinetics Of Biomass And Gasified Tar

Most of the energy sources come from fossil resources. Yet many environmental problems,such as the crisis of energy and the ineviatable increasing of CO2 in atmosphere,result from the vast use of fossil resources. So the exploation of new renewable and circulable energy sources is quite necessary. Biomass energy got much more attention than before because of many advantages such as low effect to environment and the regeneration ability. Pyrolysis is one of the most promising methods of biomass utilization in the future. Studying on the biomass pyrolysis characteristics and kinetics is the theoretical base for the utilization of biomass.Firstly, the pyrolysis characteristics of four the biomass samples ---- corn, corncob, rice hull, and straw were investigated by themogravimetric analysis technique at different conditions in N2 atmosphere and established biomass and bio-tar pyrolytic reaction dynamics model. On this basis, the most suitable mechanism functions were selected and the corresponding parameters were calculated. Secondly, comparison was made among several material characteristics of the pyrolysis, including biomass, bio-tar, and sludge and coal residue. The effect of heating rate, pressure, agitating a certain amount metallic compounds and particle diameters on the process of biomass pyrolysis were investigated. Finally, under CaO function catalytic pyrolysis, the author used actual bio-tar in the fixed bed catalytic pyrolysis unit and studied the decomposition temperature and the catalyst length to the tar catalysis effect influence. Experiment shows that:1) With the increases temperature of heating rate in biomass pyrolysis characteristics, the heating rate is linear and linear. And with the changes of heating rate, the release of volatile index value becomes greater, and the thermal decomposition is fiercer. As the gas pressure increases, the pyrolysis characteristic temperature reduces and the pyrolysis shifts to lower temperature regions. After oiling the metal compound, the pyrolysis of bio-tar appears the obvious promoter action. The particle size presents the different rules to the samples.2) The temperature of bio-tar at the max weight loss rate increases with the heating rate increasing, and DTG peak broaden; Along with the pressure elevation, the thermal decomposition characteristic temperature of bio-tar reduce and the pyrolysis shift to lower temperature regions; After combining the metal compound, the pyrolysis of the bio-tar has the obvious promoter action.3) Result showes the function R2 could describle the first stage of straw, corncob and bio-tar, the function n=1 could describle the other stage and other biomass.4) Four kinds of category's material(biomass,sludge,bio-tar and coal residue) comparisons obtain, the coal residue belongs to the higher ash lower volatile matter material, but the sludge and biomass belong to the higher volatile matter material. Four material's pyrlysis curves are similar, and they may be divided into three processes: water-lossing, volatile matter separation stage and carbonization stage. The initial analysis temperature are bio-tar