Effect Of Nickel Based Molecular Sieve On Biomass Catalytic Gasification

The increasing consumption and price of fossil energy（coal,oil and natural gas）,as well as the increasing threat of global warming,make the use of biomass more and more attractive.In the utilization of biomass,gasification technology is considered to be the first choice to convert various biomass materials into bioenergy to successfully replace fossil derived products.In this paper,the modified Ni based HZSM-5 zeolite catalyst was characterized by XRD,BET and NH3-TPD.The effect of Ce/Zr modified nickel based HZSM-5 molecular sieve with different loading amount on the gas composition of biomass three components（cellulose,hemicellulose and lignin）after catalytic gasification in CO2 atmosphere at 750℃ was investigated by infrared on-line flue gas analyzer.It was found that the acid strength of Ni based HZSM-5 zeolite increased and CO conversion increased.The addition of Zr promoted the conversion of CO in the gasification products of cellulose and hemicellulose.Compared with the parent molecular sieve,8%Ni-8%Zr HZSM-5 catalyst increased the conversion of CO from 39.42%to 73.69%.Metal Zr had a good catalytic effect on the gasification of cellulose and lignin to CH4.Ce modified Ni based HZSM-5 zeolites had strong H2 selectivity for the three components of biomass,especially for lignin,which can effectively improve the gasification efficiency.Based on 8%Ni based HZSM-5,including parent HZSM-5 and modified Ni based HZSM-5 with 8%Ce/Zr loading,three components of biomass were gasified respectively,and their effects on oil production were analyzed by gas chromatography-mass spectrometry（GC/MS）.Nickel based HZSM-5 catalyst promoted the gasification of cellulose and hemicellulose,and the products were conducive to the ring opening of cyclic compounds and the formation of short chain compounds.The results show that the content of ethers,furfural and naphthalene in hemicellulose gasification products decreases with the introduction of nickel base,and the content of cyclic furan increases to 8.19%and phenol to 13.63%.The addition of Ce promoted the hydrolysis,dehydration and cyclization of sugars in the products,and the carbon chain length gradually changed from C≥10 to C5-9,mainly chain products.