Experimental Study On Preparation Of Aromatics Of Catalytic Co-pyrolysis Of Biomass/Polypropylene

Biomass can be processed into chemicals or petroleum substitutes,and has the characteristics of"hydrogen-poor and oxygen-rich".In recent years,the comprehensive utilization method for the co-pyrolysis of biomass and"hydrogen-rich"raw materials to prepare bio-oil has been proposed.The mixing of biomass and waste plastics can effectively increase the effective hydrogen-carbon ratio of pyrolysis feedstocks,and it is expected to improve the composition distribution of pyrolysis products and improve the aromatics selectivity in bio-oils,so the following studies were carried out in this paper:Firstly,the pyrolysis characteristics and kinetics of eight biomass feedstocks were studied by thermogravimetric analyzer.The results show that the biomass pyrolysis process can be roughly divided into four stages:low temperature water loss,slow weight loss,rapid pyrolysis and residual carbon decomposition.And the temperature range at each stage varies depending on the composition of the biomass.The pyrolysis activation energy of marine biomass(25.53⁴2.07kJ·mol^-1)was significantly lower than that of lignocellulosic biomass(46.72⁷3.14kJ·mol^-1).The eight biomass direct pyrolysis liquid phase products were mainly composed of alcohols,ketones,acids,esters,furans and other oxygen-containing compounds.The content of aromatic compounds was only 1.41¹1.93%.After the addition of HZSM-5 catalyst,the relative content of oxygen-containing compouds decreased significantly,and the content of aromatic hydrocarbons was increased?12.94³3.15%?.Secondly,the co-pyrolysis of lignocellulosic biomass?bamboo,pine and palm kernel shell?and polypropylene was studied,The results showed that:Compared with single pyrolysis,the main pyrolysis temperature range of co-pyrolysis of lignocellulosic biomass and polypropylene becomes smaller;The liquid phase products of lignocellulosic biomass and polypropylene during non-catalytic co-pyrolysis were mainly the superposition of the two alone without obvious changes;With the addition of HZSM-5 catalyst,the relative content of aromatics in bio-oil increased significantly.Finally,a systematic study on the catalytic co-pyrolysis of microalgae and polypropylene was carried out.The effects of reaction temperature?500?,600?,700?,800?,900??,the mixing ratio of microalgae and polypropylene?1:0,3:1,2:1,1:1,1:2,1:3,1:0?and the ratio of catalyst addition?1:0,1:1,1:3,1:10?to liquid phase yield and aromatics selectivity were studied in a fixed bed.The mass yield of monocyclic aromatic hydrocarbons was accurately quantified by external standard method.The results showed that microalgae and polypropylene had obvious synergistic effect on the formation of aromatic hydrocarbons during catalytic co-pyrolysis.At 800?,the mixing mass ratio is 1:1,the relative content of aromatic hydrocarbons in the bio-oil can reach 77.2%,and the mass yield of monocyclic aromatic hydrocarbons can be determined by external standard method to reach 0.122g/?g·sample?.