Study On Catalytic Conversion Of Biomass To Fuel Technology

Under the dual pressure of energy and environment,the development and utilization of biomass energy has been paid more and more attention.Pyrolysis technology is the basis for the development and utilization of biomass energy.This paper used thermogravimetric analysis to conduct Pyrolysis experiments on orange peel,walnut peel,wheat straw,wood chips and Paulownia leaves.The effects of pretreatment methods(acid washing,alkali washing and hydrogen peroxide oxidation)on the distribution of elements in biomass and pyrolysis process were studied.The effects of gasification catalysts on the pyrolysis process of biomass materials were also investigated.The results are as follows:Different pretreatment methods have different effects on the pyrolysis process of biomass.The acid washing could clear the ash components of the biomass particles and dredge the pore,which was beneficial to the escape of volatile components;alkali washing could break the ester bond between lignin and hemicellulose,thereby removing lignin,reducing the C/H ratio and lowering the content of coke in the gasification product;hydrogen peroxide oxidizes with cellulose and hemicellulose,which reduces the degree of polymerization,decreases the C/H ratio and increases the volatilization content.Through the analysis of the TG and DTG curves of biomass materials which undergone specific concentration pretreatment agent handling,the biomass gasification process was divided into three steps: water crystallizing,volatilization crystallizing and combusting,coke combusting and burning.Acid washing,alkali washing and hydrogen peroxide oxidation can all have a certain impact on the pyrolysis of biomass particles.Comprehensive comparison of the three pretreatment methods shows that the acid washing is the ideal pretreatment method for it can change the distribution of pyrolysis products of biomass materials,increase the content of volatilization and reduce the content of coke.Compared with CaO,the thermalst ability of gasification catalyst Al2O3-MgO/SnO2-Fe2O3-Al2O3 is better.The scanning electron cicroscopy showed that thin sheet of active component was uniformly loaded on the metal carrier SnO2-Fe2O3-Al2O3,and its dispersion was better.The physical adsorption indicated that the specific surface area of gasification catalyst was larger,which provided a large contact area for biomass gasification.The chemical adsorption curve demonstrated that the gasification catalyst had two strong alkaline sites.The diffraction peaks of K2 O,SnO2 and Al2O3 could be clearly observed from the X-ray Diffraction(XRD).The activation energy of gasification reaction was reduced effectively through the reaction of the sample and the active component loaded on the carrier,which made the gasification reaction temperature decreasing and the reaction conditions more moderate.The continuous process of pyrolysis gas preparing fuel oil mainly included three parts: raw material pretreatment process,main reaction process and product separation and purification process.In order to meet the conditions required for gasification reaction,the biomass raw materials should undergo the steps of washing,drying,crushing,pickling,washing and drying,etc.The above raw material was passed into a gasifier through a screw sampler and then water vapor was introduced into the gasifier as gasifying agent to vaporize the biomass particles into gasification gas at a certain temperature and pressure.The impurities in pyrolysis gas was removed after the processes of cyclones,desulfurization,denitrification,etc.The syngas was passed into the water vapor conversion tower to regulate the ratio of CO and H2.And then the syngas was passed into Fischer-Tropsch synthesis tower to synthesize the liquid fuel by separating products.The Aspen plus chemical process simulation software to establish the model,explore the preparation process of fuel oil catalytic system was born material optimal operating conditions,respectively,feed rate of 3t·h-1,pretreatment agent 7% nitric acid,heating rate of 10?/min,the diameter of 1mm,the catalyst amount is 10% and residence time is 6s.