Design,Preparation Of MIEC And Its Structure-Function Relationship In Bagasse Lignin Catalytic Pyrolysis

Lignin is the second largest renewable biomass resources besides cellulose on earth,the reserves of lignin are abundant and the regenerative velocity is fast.There are a lot of functional groups,such as carbon chain,aromatic ring methoxyl,hydroxyl and carboxyl in lignin which can be used as raw materials produced phenols and other high value-added fine chemicals.The catalyst can reduce activation energy of selective broken key reactions,improve the reaction rate,adjust the objective product selectivity and yield during lignin pyrolysis.Develop and design high selective catalyst can selective activation,break one type of chemical bond,selective catalytic preparation of one kind of chemicals,improve lignin economy and achieve its environment-friendly conversionChemical conversion from bagasse lignin into chemicals is one of the important ways to realize its resource utilization and high value utilization.A series of perovskite-type mixed ionic and electronic conductors(MIEC)CaZr1-xFexO3 and LaTi1-xFexO3 were prepared using the solid state method.The crystal form,morphology,metal valence state and thermal stability were characterized by XRD,SEM and XPS.The pyrolysis and catalytic pyrolysis processes of bagasse lignin were tested by thermogravimetry.The catalytic performance of CaZr0.8Fe0.2O3 and LaTi0.2Fe0.8O3 was evaluated in a fixed bed micro-reactor.The liquid products of bagasse lignin catalytic pyrolysis were analyzed by gas chromatography/mass spectrometry.The research results are as follows:(1)The results show that the CaZr1-xFex O3 pellets after calcinations deposit randomly in the form of irregular grains of flake with compact structure.As the doping amount of Fe increases,the characteristic peaks of mixed ionic and electronic conductor shift to large angle,the cell volume of crystal and the grain size decrease.The structure of catalyst LaTi1-xFexO3 synthesized by solid state is smooth;the grains size distribution is uniform;the characteristic peaks are clear and the crystalline the gains have good crystallinity.The intensity of diffraction peaks increasing with the temperature rising to a certain extent.There are no new characteristic peaks generate with increasing the roasting time,but the catalyst grains can grow fully.(2)Thermogravimetric analysis results show that lignin weightlessness mainly occurred in 180-550°C.Add catalyst can accelerate the reaction rate of lignin pyrolysis,reduce the production of coke and promote its catalytic conversion.(3)In the test of fixed bed micro-reactor,the liquid product by bagasse lignin and CaZr0.8Fe0.2O3 pyrolysis was mainly consisting with benzene,phenols,guaiacyl,catechol,syringyl and methoxyl aromatics.When the mass ratio of the bagasse lignin and CaZr0.8Fe0.2O3 was 2:1;the selectivities were 25.01 wt.%,35.19 wt.%,6.18 wt.%,10.68 wt.%,14.21 wt.% and 8.73 wt.% respectively.(4)In the test of fixed bed micro-reactor,the selectivities of benzene,phenols,guaiacyl,catechol,syringyl and methoxyl aromatics were 11.93 wt.%,37.08 wt.%,14.14 wt.%,6.42 wt.%,16.55 wt.% and 13.88 wt.% respectively when the mass ratio of the bagasse lignin and La Ti0.2Fe0.8O3 was 2:1.(5)Perovskite type mixed ionic and electronic conductors Ca Zr0.8Fe0.2O3 and La Ti0.2Fe0.8O3 were regenerated after the catalytic pyrolysis of bagasse lignin.Contrast the XRD and SEM of the catalysts before and after reaction found that the catalysts have high catalytic activity and structure stability.