Experimental Study Of Microwave Heating Methods And Novel Catalysts For Tar Model Compound Removing

Biomass gasification technology,as one of the most efficient use of biomass energy technology,has broad application prospects.However,the formation of tar restricts its development,which is urgent needed to be solved.At room temperature,tar can easily condense into liquid and mixed with fly ash,sticking to the gas pipelines,valves and gas transportation equipment,then affecting the normal and stable operation of the system.At the same time,the presence of tar can result in a decrease of total efficiency.Therefore,how to reduce the tar content in the gasification gas have attached great attention of researchers at home and abroad.Although tar removal methods have been researched by many researchers,there exits fast carbon deposition and catalyst deactivation.On the basis of the study about biomass tar removal carried out by predecessors,this graduation-article conducted in-depth testing and research on tar cracking technology adapting to our application.The main duties include the following aspects:(1)Taking coke as a cracking-carrier,there investigated cracking of coke for different tar model compounds and different temperature on small catalyst evaluated equipment,compared with the traditional carrier Al2O3.And also there analyzed the main component of products after toluene being cracked.(2)Focusing attention on revealing the relevant law about microwave on thermal cracking of toluene using coke as the microwave-absorbing carrier.(3)On the basis of the research of thermal cracking of toluene,novel Co/C catalyst was prepared to crack toluene.The author observed the effect of molar ratio of Co to C?temperature?the feed concentration of toluene?the flow of carrier gas on the cracking efficiency?deposit carbon efficiency and generated hydrogen efficiency of tar model compound after being catalytic cracking.What's more,catalyst with Co2O3 as an active center was investigated to the toluene being catalystic cracked.Experimental results show that:When contrasted conventional pyrolysis carrier Al2O3 to coke,they had the same ability to crack toluene,but the coke deposit fractional yield of toluene rated from 17.06%to 4.16%,which showed coke a novel type of thermal cracking carrier;after toluene being thermal cracked,there produced a mixture of gases containing mainly light component of low-carbon gas?carbon and fused-ring compounds.Although heating using microwave was faster than that of conventional electric furnace,the temperature can not continuously keep stable,a lot of data showed the temperature remained relatively constant at about 650? after 14min.Compared microwave heating with furnace heating using in toluene cracking process,there found that to achieve the same temperature,microwave heating needed less time than the furnace heating required,with a slightly higher conversion of toluene and slightly lower coke deposit fractional yield of toluene.When the optimized Co/C catalyst(with 15.91wt%Co loading amount)was subjected to conditions of 650? with the flow of carrier gas being 40ml/min and the concentration of toluene being 5.55Kg/Nm3,the experimental results indicated that the conversion of toluene,H2 content in exit gas and the coke deposition fractional yield were 100%,84.00%and 6.56%respectively.When compared with {Co2O3}C40.86 and CoC14.52 catalysts,it was found that the Co active center existed in both of them.