Molecular Sieve Catalyzed Biomass Pyrolysis To Prepare Liquid Fuel

Bio-oil prepared by biomass pyrolysis has low calorific value,poor stability,high viscosity,acidity and corrosiveness,which limits the application of bio-oil.Molecular sieve-catalyzed bio-oil cracking is an effective way to improve the quality of bio-oil.However,during the upgrading process of bio-oil catalytic cracking,there are problems such as low yield of hydrocarbon products and easy carbon deactivation of molecular sieve catalyst.This study from the perspective of matching the molecular size of biomass pyrolysis bio-oil to the molecular sieve,researching with walnut shells and pine shavings as raw materials,carry out research on the preparation of high-quality liquid fuels by the catalytic pyrolysis of biomass.Fast pyrolysis experiments of pine shavings and walnut shells were carried out at different temperatures,useing the pyrolysis gas-mass spectrometry technology(Py-GC/MS)the composition and content of pyrolysis bio-oil from pine sawdust and walnut shell were studied.And the Bird empirical formula combined with the Joback group contribution method was used to obtain the dynamic diameter of each molecule in the pyrolysis bio-oil and study the molecular dynamics diameter of bio-oil.The distribution range of the dynamic diameter of pine sawdust pyrolysis bio-oil is[0.509,0.866)nm,and the distribution range of the kinetic diameter of walnut shell pyrolysis bio-oil is[0.413,0.881)nm,and the kinetic diameter of walnut shell pyrolysis bio-oil is mainly distributed in the range of[0.500,0.750)nm.When the pyrolysis temperature is 600°C,the hydrocarbon products in the walnut shell catalytic pyrolysis bio-oil are mainly long-chain hydrocarbons and aromatic hydrocarbons.When the pore size of the molecular sieve is larger than the ideal matching size of walnut shell pyrolysis bio-oil,the closer the pore size of the molecular sieve is to the matching size,the higher the yield of hydrocarbons;the larger the pore size of the molecular sieve,the less conducive to Leucoglucosan catalytic conversion and the more conducive to the formation of long-chain compounds.The content of hydrocarbons in the bio-oil obtained by catalytic cracking of Si O2 molecular sieve is48.30%,and the content of long-chain compounds is 27.53%Si₂₀molecular sieve was used to catalytically pyrolyze walnut shells at different temperatures.The results show that the higher the temperature,the better the deoxygenation effect,the higher the yield of hydrocarbons,and the better the catalytic performance of the catalyst;Si₂₀molecular sieve is beneficial to catalyze the formation of long-chain organics,and the content of long-chain organics increases with the increase of temperature;The change of temperature did not have a significant effect on the dynamic diameter of walnut shell catalytic pyrolysis bio-oil molecules.