Applied Basic Research On Catalytic Cracking Tar By Brown Gas (HHO) In The Biomass Pyrolysis Process

Biomass pryolysis technology is an effective method to utilize biomass energy efficiently,which can also alleviate the national non-renewable energy crisis and environmental pollution problems.As an intermediate product of the biomass pyrolysis process,tar is easy to condense at low temperature and cause the blockage or corrosion of the equipment.The efficiency of biomass pyrolysis is reduce because of the gas and pryolysis gas caused by high temperature is difficult to remove.Brown gas itself has the advantages of easy preparation,good catalytic properties,and non-polluting combustion,which avoids the defects of slagging and uneven reaction contact caused by other solid catalysts in practical applications.In order to solve a series of negative effects caused by tar during the process of biomass pyrolysis,this article propose a method of adding a small amount of Brown gas(HHO)during the biomass pryolysis process to promote tar cracking.Based on the CHEMKIN simulation software platform and used Phenol,toluene,benzene,methyl naphthalene and xylene as the model compounds of tar,this paper established a Brown gas-biomass tar gas phase chemical reaction kinetic model to study the biomass tar cracking under the condition of adding Brown gas,The simulation results verified that HHO can promote the feasibility of tar cracking in the process of biomass pyrolysis,which provides a theoretical basis for subsequent experiments.A fixed-bed micro-experimental platform combine with the catalytic and cracking of Brown gas and biomass pyrolysis tar was established.During the experimental process,the disadvantages of choosing only one or several tar components as the research object in the previous tar cracking research were abandoned,the gas phase tar in biomass pyrolysis gas was taken as the main source,and used CT-Cold Trapping Method and gravimetric analysis method sampling and analyzing the tar in pryolysis gas.The effect of Brown gas(HHO)on the tar content during the biomass pyrolysis process in the fixed tube furnace was experimentally studied.With the pyrolysis temperature increased from 500℃to 1000℃,the content of pine pyrolysis gas decreased from 67.76 g/Nm~3 to 47.40g/Nm~3 without HHO.Compare to the process without HHO,when 1%HHO was added in the pyrolysis process,the decrease rate of tar content in pyrolysis gas were 1.18%,1.90%,0.86%,2.66%,1.56%and 1.48%respectively,HHO has the most obvious promoting effect on tar cracking at the temperature of 800℃.When 5%concentration of HHO was added,the promotion effect of HHO tar cracking is obviously better than that of 1%concentration of HHO.The promotion effect was the most obvious when the pyrolysis temperature was 800℃When the pyrolysis temperature is higher than 800℃,the promotion effect of increasing the HHO concentration in tar cracking was not significantly different from that when 1%HHO is added.Thus the pyrolysis temperature is too high had no better promotion effect on tar cracking when the concentration of HHO was keep increasing.According to the experimental data,the addition of HHO can promote the fracture of carbonyl group in tar components,and has a certain catalytic effect on tar cracking.The increase of HHO concentration can further promote tar cracking,and the promotion effect is the most obvious at the temperature of 800℃with the increase of lyrolysis temperature.Based on the data obtained under the optimal experimental condition,this paper calculated that the theoretical value of HHO for each 1 g of tar cracking is 0.0348 Nm~3/h,which further illustrated the HHO economic efficiency in the promotion of tar cracking.