Study On Catalytic Pyrolysis Of Biomass Based On Fe/Zn Modified ZSM-5

The development of modern society requires the support of energy.This development rule has led to an increasing demand for energy.Many aspects of energy,such as stable supply,cleanliness,and sustainability,have also received increasing attention.China's energy structure is still dominated by fossil energy.On this basis,new energy is continuously developed and the proportion of new energy expanded.Biomass is a renewable resource,but the biomass itself has a low energy density and a limited usable range,so the resource utilization of biomass is of great significance.There are many ways to utilize biomass resources,including direct combustion,biological fermentation,and pyrolysis.Among the various methods of biomass resource utilization,pyrolysis is a more efficient utilization method.Biomass pyrolysis can usually obtain gas,liquid and solid three-state products,including biochar,bio-oil and bio-gas.The main research object of this subject is the bio-oil components obtained from biomass pyrolysis.In this study,sawdust and peanut shells were selected as the research objects of biomass pyrolysis.The experiments include two types of pyrolysis methods:tube furnace and pyrolysis gas chromatography-mass spectrum?Py-GC/MS?.Characteristics of postgraduate pyrolysis products of 550?.The main research contents include three-state yield analysis of pyrolysis products,analysis of the characteristics of bio-oil and bio-gas components,and analysis of the mechanism and correlation of bio-oil components.Biomass pyrolysis experiments mainly include two conditions:direct pyrolysis and catalytic pyrolysis.The catalysts used in catalytic pyrolysis experiments are divided into two types:ZSM-5 molecular sieve catalysts and metal modified catalysts.In this study,two metals,Fe and Zn,were selected to carry different metal loadings on ZSM-5 molecular sieves to obtain 6wt.%Fe,6wt.%Zn,3wt.%Fe+3wt.%Zn?6Fe,6Zn,3Fe3Zn?metal modified catalysts.This study used X-ray diffraction?XRD?,scanning electron microscopy?SEM?,Fourier transform infrared spectroscopy?FT-IR?,specific surface area test,NH₃-TPD analysis and other characterization methods to explore the physical and chemical changes of the catalyst.The analysis found that the main structure of the metal-supported catalyst did not change much.However,the characteristics of Fe load show that the average pore size and other parameters increase,and there are obvious agglomerations in the SEM image,while the Zn load has no physical changes similar to the Fe load.In terms of chemical characteristics,acidic site analysis found that the peaks of acids and strong acids in Fe and Zn modified catalysts shifted to the high temperature region,and the strongest peaks of 6Zn catalysts were the strongest.The composition characteristics of bio-oil were analyzed,and it was found that the composition of wood chips and peanut husks were different in direct pyrolysis at550?.In the pyrolysis of wood chips,3Fe3Zn catalysis can maintain higher yields of aromatics and phenols.At the same time,3Fe3Zn catalysis also reduced the proportion of bio-oleic acid components.In peanut shell catalytic pyrolysis,the highest yield of aromatics was 6Zn catalytic pyrolysis,and the generation of aldehydes and ketones was reduced.The 3Fe3Zn catalyst has a slight advantage in the inhibition of acid substances,and has obtained the highest phenol yield.In the analysis of the correlation between the phenol and Benzene-Toluene-Xylene?BTX?products and the catalyst pore size,it is found that there may be a certain correlation between the products and the catalyst pore size in the catalytic pyrolysis of sawdust.This research can be divided into three parts,including metal modification and characterization of ZSM-5 molecular sieve catalyst,catalytic pyrolysis experiments on biomass raw materials,and preparation and analysis of three-state products obtained by pyrolysis.The experimental study of product characteristics under biomass catalytic pyrolysis has certain guiding significance of the wide-scale promotion of biomass catalytic pyrolysis.