Research On The Dynamic Size Of Bio-oil Molecules And The Shape-selective Selectivity Of The Catalyst Pore Size

In order to study the catalytic pyrolysis characteristics of biomass,as well as the kinetic size of biomass pyolysis products and selectivity of the molecular sieve pore size,this paper finished some experimental research work.The research results are as follows:The content and distribution of cellulose and lignin are studied by Py-GC/MS at 350℃ to 600°C.It is found that the products of fast pyrolysis of cellulose are mainly composed of ketones,esters,alcohols,aldehydes,furans,hydrocarbons and aromatic compounds.When the pyrolysis temperature increased from 350°C to 500°C,the yield of furan compounds increased accordingly.The compounds obtained by fast pyrolysis of lignin are mainly alcohols,ketones,phenols,esters and acids containing hydroxyl,methoxy,methyl,phenyl,ethyl and propenyl groups.Six zeolites are used to catalyze the pyrolysis of cellulose and lignin at 600 ℃ to study the shape selectivity of zeolite.The zeolites used in this study include MCM-41,MCM-22,ZSM-5,Na Y,SAPO-34,and SBA-15,which have different sizes of aperture.The critical parameters of the kinetic diameter are calculated by the group contribution value.Then the kinetic diameter of the pyrolysis products is calculated by the Joback method,and it can be concluded that the size distribution range from 5.00-8.50 ?,but the kinetic diameter of products is concentrated on the 5.00-7.00?.By comparing the content of hydrocarbons in cellulose and lignin pyrplysis products catalyzed by molecular sieves at 600°C,the theoretical matching of the dynamic diamet er of the bio-oil molecules with the size of the molecular sieve is analyzed,and the factors that influence the theoretical analysis and the experimental results are analyzed.Finally,it is concluded that the pore size of the molecular sieve between 5.60 ? to 7.40 ? is the best catalyst when the catalytic pyrolysis of cellulose and lignin is carried out.