Research On Catalytic Fast Pyrolysis Of Biomass With Noble-like Catalysts To Produce High-grade Bio-oil

Fast pyrolysis for bio-oil preparation is one of the most efficient way to utilize biomass.Compared with biomass materials,bio-oil has gained more attention due to its advantages including high energy density and easy for transportation.However,bio-oil from traditional pyrolysis is a complicated liquid with low heating value,strong causticity and low stability,which can only be used as low grade liquid fuel.To prepare high-grade bio-oil,catalysts were introduced to pyrolysis process to selectively adjust the product distribution.Typically,noble metal catalysts performed well on promoting the grade of bio-oil due to the excellent hydrodeoxygenation capability.But the cost of noble catalysts limited the application in industry.As novel hydrogen-involving catalysts,transition metal carbides,nitrides and phosphides presented similar catalytic properties to noble metal catalysts,hence to be known as noble-like catalysts.Currently,little studies have been reported on noble-like catalysts for biomass pyrolysis.In this work,several noble-like catalysts were prepared to investigate the catalytic fast pyrolysis characteristics of biomass.1.Catalytic fast pyrolysis of pine milled wood lignin with different noble-like catalystsActive carbon（AC）supported catalysts,W₂C/AC,W₂N/AC,WP/AC,Mo₂C/AC,Mo₂N/AC and MoP/AC were prepared for Py-GC/MS experiments to compare the effect on pyrolytic products distribution of 6 noble-like catalysts with noble catalyst Pd/SBA-15.Results showed that,despite MoP/AC,noble-like catalysts could promote the decomposition of lignin to form phenolics as well as increase the yield of pyrolytic products,which was similar to the catalytic effect of Pd/SBA-15.Moreover,the catalytic performance of W₂C/AC and W₂N/AC were better than Pd/SBA-15.Tungsten loading and catalyst-to-MWL ratio have great effect on the product distribution.The optimal yield of total pyrolytic products,about 1.34 times of non-catalytic process,was achieved at 10%W₂C/AC and catalyst-to-MWL of 5.2.Catalytic fast pyrolysis of biomass with W₂C/AC catalyst to produce high-grade bio-oilW₂C/AC catalyst was used to catalyze high-grade bio-oil preparation from biomass prolysis.Effects of pyrolysis temperature,catalyst-to-biomass ratio on product distribution were investigated by Py-GC/MS experiments.Results suggested that W₂C/AC catalyst could significantly facilitate the conversion of pyrolytic products of holocellulose and promote the decomposition of lignin to form phenolics.Also,phenolics with unsaturated phenolics could be converted to saturated phenolics.Based on the quantitative results of 10 phenolics,the highest relative concentration of 41.9% and actual yield of 7.05mg/g were achieved at 400 oC and catalyst-to-biomass ratio of 1.5.3.On-line catalytic cracking of pine wood fast pyrolysis vapors with Mo₂N/HZSM-5 for aromatic hydrocarbons productionMo₂N/HZSM-5 catalyst was prepared for on-line catalytic cracking of pine wood for aromatic hydrocarbons production.Effects of pyrolysis temperature,catalyst-tobiomass ratio on product distribution were investigated by Py-GC/MS experiments.Results showed that HZSM-5 has good selectivity on aromatic hydrocarbons,but containing abundant polycyclic aromatic hydrocarbons.While Mo₂N/HZSM-5 catalyst could inhibit the formation of polycyclic aromatic hydrocarbons and promote the formation of monocylic aromatic hydrocarbons.The highest aromatic hydrocarbons selectivity of 84.10% was achieved at 750 oC and catalyst-to-biomass ratio of 9.