Research On Three-component Microwave Pyrolysis Of Biomass

Biomass energy is one of the most abundant renewable energy sources.It has the advantages of low cost,wide distribution and easy availability.It is of great significance for its resource utilization to relieve energy pressure and reduce environmental pollution.Microwave pyrolysis is one of the effective means to treat biomass.Microwave heating of biomass pyrolysis has the characteristics of fast heating rate,good uniformity and low pretreatment cost.Microwave pyrolysis of biomass is a very complex physical and chemical process,which can be considered as a comprehensive manifestation of the microwave pyrolysis behavior of the three components of biomass,lignin,cellulose and hemicellulose.Therefore,the three-component microwave pyrolysis process of the graduate material can better reveal the mechanism of microwave pyrolysis of biomass,which is conducive to product regulation.First,the microwave pyrolysis characteristics of eupatorium adenophorum and camellia husk and its simulated materials are studied.The results show that the bio-oil product components of eupatorium adenophorum and camellia husk and its simulated materials are mostly the same.The content of H₂ and CO in the gas products of eupatorium adenophorum and camellia oleifera husk is higher than that of their simulated materials.Scanning electron microscopy analysis of biochar showed that the pyrolysis carbon morphology of eupatorium adenophorum is different from the simulated material of eupatorium adenophorum,the simulated material of camellia husk,and the husk of camellia oleifera,and it appears porous.Microwave pyrolysis and conventional pyrolysis of the three components of biomass were carried out at 300～700℃.It was found that the solid yield of lignin microwave pyrolysis was much higher than that of cellulose and hemicellulose,while cellulose and hemicellulose The liquid product of microwave pyrolysis is much higher than that of lignin.Targeting high yields of liquid products,lignin reached 10.10 wt.%at 600°C,cellulose reached 26.00 wt.%at 500°C,and hemicellulose reached 30.00 wt.%at 400°C.Three-component microwave pyrolysis of biomass is more conducive to the generation of gas and solid products,and conventional pyrolysis is more conducive to the production of liquid products.Microwave pyrolysis produces more H₂ and CO than conventional pyrolysis,but less CH₄ and CO₂,so the gas product of microwave pyrolysis has a higher heating value.Finally,KCl,Mg Cl₂ and Fe Cl₃ were selected as additives to study the influence of the three-component pyrolysis process of biomass.The study found that KCl and Mg Cl₂ caused a decrease in liquid products and an increase in solid yield;Fe Cl₃caused a decrease in liquid and solid,and promoted gas production.KCl and Mg Cl₂ increase the CO₂ and H₂ content in the gas,while the CO and CH₄ content decreases.Fe Cl₃ has a certain catalytic effect on the formation of syngas（CO+H₂）,which improves the yield of syngas,and increases the yield of syngas for lignin,cellulose and hemicellulose by7.38 vol.%,10.03 vol.%and 12.51 vol.%.