Experimental Study Of Tar Formation Mechanism And Novel Biomass Gafication Combining With Tar Cracking

Biomass is not only a kind of renewable and inexhaustible enegy,but also possesses the advantages of the low carbon and protecting environmental.Abandoned the straw,chaff and other biomass can be converted to gas through biomass gasification,The generated gas can be direct combustion or used as the material of producing other chemical products.The tar occurred in the process of biomass gasification,which can clogged pipes with flying ash,this paper studied the formation mechanism of tar.A kind of novel biomass gasification reactor connected with tar catalytic cracking was developed and studied.The reactor can not only effectively remove tar and prevent tar with flying tar clogging pipes,but also don't need heat supply source,it brief technological process.The main contents includes the following parts:?1?Biomass is composed of lignin and cellulose,looked at the influence of lignin and cellulose on the tar composition at different temperature,have the conclusion that cellulose produce the tar composition,which mainly contain acid,aldehyde,ketone,phenol components in the process of pyrolysis and lignin produce the tar composition,which mainly contain benzene,toluene components in the process of pyrolysis.With the rise of temperature,the part component such as aldehyde,ketone,phenol cracking happens to polycyclic aromatic compounds in the secondary.?2?Most of the existing biomass gasification reactor use the method of adding catalytic cracking bed after the biomass gasification reactor removing tar.Because the reaction of tar catalytic pyrolysis is an endothermic reaction,it need add extra heat supply source and make the process complex.In addition,Tar is part of the condensation in the process of gas transfer.In order to solve the problem,a kind of novel biomass gasification reactor connected with tar catalytic cracking was developed and this reactor was studied about cold experiment.looked at that on the condition of cold experiment,the relationship of the sample rate and rotate speed of fine wood powder,wood powder,chaff and the turmeric slag,on the condition of weather have catalyst or different air quantity,and the change of the system pressure difference in the process of biomass entering reactor.?3?On the condition of hot experiment and With air as the gasification medium,explore the effect of ER on the gas volume fraction and the best ER was 0.23.Sawdust has been used as feedstock and the rat of screw feeding was kept at 8.00r/min,the temperature of biomass gasification was at a range of 500-670?,the catalytic cracking temperature of tar was at 800?,ER was controlled at 0.23.The experiment compared the result of gas composition with Co-based catalyst and without Co-based catalyst.H₂ volume percent increased from 14%without Co-based catalyst to 34%with Co-based catalyst,besides,with the Co-based catalyst the tar was found to be cracked completely.The characterizations of catalysts were tested by XRD,SEM.?4?Oxygen gas was used as the gasification medium,The experiment compared the result of gas composition on the condition of whether have Co-based catalytic and whether sawdust have CaO.Have the conclusion that using the oxygen as the gasification medium,the volume fraction of combustible gas reduced,The CaO which was added to the sawdust have the effect of the C02 capture,the reducing of C02 concentration was beneficial to the reaction of CO and H₂0,lead to the CO concentration reduced and H₂ concentration rised.