Investigation On Co-Pyrolysis And Catalytic Pyrolysis Characteristics Of Bamboo And Polypropylene

Biomass is the only renewable resource containing carbon,and its efficient conversion and high-quality utilization are of great significance to solve energy and environmental problems.The products from biomass direct pyrolysis are not suitable to use as high-value chemical for its hight oxygen content.It is the simplest method to improve the H/C_eff of raw materials and the quality of products that co-pyrolysis plastics and biomass.However,the co-pyrolysis and catalytic co-pyrolysis processes are still unclear,and the product quality still needs to be improved.The kinetic characteristics and product distribution of biomass and plastic co-pyrolysis is studied.Base on the results of co-pyrolysis,the co-pyrolysis and catalytic reforming to produce syngas and carbon materials is investgated.Firstly,bamboo and polypropylene are selected as the typical samples of biomass and plastics to study the weightlessness and kinetic characteristics of co-pyrolysis at different heating rates and plastic ratios.Popescu method is used to determine the mechanism function of co-pyrolysis,and various kinetic methods（Friedman Starink,Coal-Redfern）are used to calculate the kinetic parameters.As the heating rate increase,the maximum rate of weight loss base on temperature is reduced.With the increase of the plastic ratio,the ending temperature of co-pyrolysis decreased,while the main temperature range for co-pyrolysis is shortened.Due to the synergistic effect,the biomass reaction activation energy decreases,the plastic reaction activation energy increases,and the total activation energy for co-pyrolysis reduces.Then,the product distribution of bamboo and polypropylene co-pyrolysis at different pyrolysis temperature and plastic ratio is investigated on a fixed bed reactor.What’s more,HZSM-5 is used to adjust the co-pyrolysis volatile component.At 400 ^oC,the pyrolysis of biomass and plastic is not complete.The high temperature promoted the formation of small molecule gas products.With the increase of plastic ratio,the hydrocarbon products increased and the oxygen-containing substances decreased.When the plastic ratio is 0.6,the yeild of oil and the BTX peak area in liquid products is largest.The synergistic effect between biomass and plastics further promoted the generation of hydrocarbons and inhibited the generation of oxygen-containing substances.Finally,the HZSM-5 catalyst and Fe-Ni/Al₂O₃ catalyst are used to catalyze the co-pyrolysis of bamboo and polypropylene on a fixed bed reactor.The conditions of co-pyrolysis process are optimized,and the characteristics of the co-pyrolysis and catalytic reforming products are analyzed.At the plastic ratio is 0.6,when the pyrolysis temperature is 500 ^oC and the HZSM-5 weight is 5 times to feedstock,the optimal syngas yield and deposited carbon yield can be obtained.With the increase of the plastic ratio,the yield of hydrogen increased,and the proportion of fiber carbon in the deposited carbon increased.It’s a way for high value utilization biomass and plastic that catalystic co-pyrolysis in the effect of zeolite catalyst and Fe-Ni metal catalyst.