| Biomass and waste tyre could be both considered as renewable energy to recycle and reuse. In recent years, many researchers pay more attention to pyrolysis technology. However, the oil can not be directly used as alternative fuel because of the deficiencies of oil derived from single pyrolysis of biomass, for example, high density and oxygen content, and thermal instability. When biomass and waste tyre were co-pyrolyzed, free radical oxygen produced by pyrolysis of biomass could damage other hydrocarbon radicals derived from waste tyre, which contains high carbon and low oxygen. This could prohibit some undesirable compounds, so as to improve the properties of liquid; at the same time, it may promote the generation of desired products.Based on the above understanding and the existing problems for the pyrolysis of biomass alone, with respect to the research foundation of our group, this study is as follows, biomass and waste tyre were co-pyrolyzed in fixed bed at 500℃. The influence of types of biomass, different mixture proportions of biomass and tyre and different catalysts on co-pyrolysis were studied. The properties, constitution, PAHs concentration and elemental analysis of the oil were investigated by GC-MC, GPC, GC and XRD.Through the study of co-pyrolysis of biomass and waste tyre, the properties of oil were not the same when different biomass and tyre were co-pyrolyzed. The order of different biomass regarding to density was sawdust > rice husk > corn cob; and regarding to HHV, the order of different biomass was rice husk > corncob > sawdust. The content of PAHs was the highest when corn cob was co-pyrolyzed with waste tyre, while the sawdust was the lowest. When the proportion of rice husk and waste tyre was 75 : 25 using SBA-15 as catalyst, the density and viscosity of oil were 0.9507 kg·L-1 and 5.60 mm2·s-1, respectively. After supporting cobalt, the density and viscosity of oil were reduced to 0.938 kg·L-1 and 4.74 mm2·s-1, decreased by 1.37% and 15.4%, respectively. SBA-15 supported with molybdenum restrained the generation of PAHs, contrary to the using of SBA-15, the content of PAHs was higher when using Co/SBA-15. The content of carbon, hydrogen and mole ratio of H/C increased more using supported catalysts than using SBA-15, while the content of oxygen decreased. The average molecular weight of oil decreased with the supported catalysts. Among the selected catalysts, MoCo/SBA-15 can obviously decrease the molecular weight, which decreased by 21.2% than using SBA-15. The crystal structure of SBA-15 was not damaged after supporting of molybdenum and cobalt, but its peak intensity of diffraction decreased slightly. The pyrolysis process for the volatile substance can be described by first order model with the method of Coats-Redfern.
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