Experimental Study On Biomass Catalytic Cracking Based On Novel Composite Catalyst

Energy is the material basis that supports the progress of human civilization and the improvement of living standards.It is an indispensable basic condition for the modern society to develop industrialized and intelligent.For a long time in the future,fossil energy still dominates China’s energy structure,but with the economic growth,fossil energy is depleted and environmental pollution is also coming.At the same time,the pressure to protect the ecological environment and cope with climate change is increasing.Therefore,we urgently need the green transformation of energy.The utilization of biomass energy can resource and energy the agricultural and forestry waste.Biomass energy is a clean energy product that can replace coal,fuel oil and gas.It is an ideal and economical clean fuel for solving fossil energy pollution in China.First,it has far-reaching significance for protecting the environment and conserving resources.Compared with traditional fossil fuels,biomass has the advantages of low cost,energy saving,and significant reduction of air pollution.It can basically achieve zero carbon emissions and low nitrogen and sulfur pollution in the environment.It is easy to store,transport and use.Therefore,vigorously develop low-carbon biomass industry based on biomass energy,partially replace and save fossil energy,help improve energy structure,reduce carbon dioxide emissions,and mitigate and respond to global climate change.Biomass catalytic cracking is an important way of thermochemical conversion of biomass,and the process is complicated.It is mainly the process of high temperature thermal degradation of biomass under the action of catalyst to finally form three-phase products of combustible gas,bio-oil and charcoal.As far as the current research is concerned,due to the complexity of the composition of the product,its low calorific value,instability,the correlation analysis of the reaction characteristics of the analysis of biomass steam vaporization and catalytic cracking is not deep enough.Finding a suitable catalyst can effectively promote the catalytic cracking of biomass,and there are still limitations on the type of catalyst selection.In addition,although dolomite can effectively catalyze the biomass cracking reaction,due to its poor mechanical strength and short service life,the research on biomass catalytic pyrolysis is limited to the pyrolysis gasification group.The experimental analysis of the dolomite catalyst itself,so the analysis of the catalytic mechanism of the dolomite composite catalyst is not clear.This experiment introduces the concept of enthalpy to analyze the effect of temperature and steam flow on gas gasification performance indicators.Using the new porous composite catalyst lanthanum-iron-dolomite（La-Fe-Dol）as the catalyst,the self-made down-suction steam gasification furnace was used as the experimental system,and the discarded pine wood chips were taken as the research object,using X-ray diffraction.The infrared spectrum of the leaf was used to analyze the functional group and composition of the new porous composite catalyst La-Fe-Dol.At the same time,combined with the gas phase composition change,the gas cracking gasification reaction characteristics of the graduated materials were studied,and the different catalyst combustion temperature,heating rate and catalyst compound ratio were studied.The effect of catalyst yield,functional group and surface topography.And further improve the biomass catalytic cracking experimental platform based on different gasification temperature,water vapor flow rate and the presence or absence of catalyst,composite catalyst and single dolomite catalyst comparison on the thermal cracking gas composition,carbon conversion rate.In this paper,the experimental study on biomass catalytic cracking of porous composite lanthanum-iron-dolomite as catalyst was introduced from the following aspects:Then this paper introduces the research from following parts:The first,preparation of a novel composite catalyst lanthanum-iron-dolomite（La-Fe-Dol）and analysis of its catalyst morphology:preparation of a new composite lanthanum-iron-dolomite（La-Fe-Dol）by gel-sol method.A composite catalyst LaFeO₃-Dol having a porous structure in a fixed ratio can be obtained.Studies have shown that when the preparation temperature is 3K/min at 750℃,the catalyst has a smaller pore structure and the specific surface area increases significantly.The second,at a steam flow rate of 0.3 kg/h,the volume fraction of H₂ in the gas increases with the increase of temperature,and the volume fraction of CO decreases first and then increases.The volume fraction of CH₄ is consistent with the temperature.Reduction;when the steam flow rate increases to 0.6kg/h,the change trend is similar,and the appropriate increase of the steam flow can obtain hydrogen-rich gas.Under different steam flow rates,the gas enthalpy efficiency changes with temperature and the gas low heat value is the same as the temperature increases first and then decreases.When the enthalpy efficiency is maximum,the steam flow rate increases from 0.3 kg/h to 0.6 kg/h.Third,a new porous composite catalyst（La-Fe-Dol）catalyzed biomass steam steamification experimental study:the new porous composite catalyst can effectively improve the hydrogen content in the vaporization pyrolysis gas,compared with the single dolomite catalyst,the H₂ volume fraction increase Large;composite catalyst can promote the decomposition of vaporization reaction into small molecules such as hydrocarbons and gasification gas.Compared with the composite catalyst before and after catalytic cracking,the morphology of the new porous composite catalyst（La-Fe-Dol）changed little before and after pyrolysis,reflecting that its surface area carbon and mechanical strength improved to a certain extent.The significance of this research is as follows:（1）Studying the influence of temperature and steam flow on gas characteristics and performance indexes of gasification process from the perspective of enthalpy,and providing a basis for deepening the nature of postgraduate material gasification reaction.（2）Study on the catalytic properties of La-Fe-Dol composite catalyst prepared by sol-gel method.Adding rare earth element lanthanum（La）to dolomite modification,the production energy consumption is reduced,and the biomass cracking gasification gas production rate is improved.It provides a basis for the further study of novel composite catalysts in biomass catalytic cracking.