The Experimental Study On Biomass Charcoal-gas Cogeneration In Fixed-bed

Today,the energy consumption of world is mainly some non-renewable energy sourcessuch as coal,oil and natural gas.Over-exploitation and utilization of non-renewable energysources,not only caused the energy crisis,but also made the problem of environmentalpollution more and more seriously.Therefore, the development and utilization of renewableenergy sources will become the inevitable trend of global energy consumption.The fixed-bed biomass charcoal-gas cogeneration system which be studied in thispaper is for non-polluting,renewable,raw material reserves and more development andutilization of biomass energy production process systems.The basic principle of the systemis that through the heat by the spontaneous combustion of the gas which produced from theinner gasifier to complete the carbonization process of the material in the outer tube.Thisnot only reduces the energy consumption of coking chamber carbonized and the system canproduce some other products which can be secondary use such as charcoal,gas and biomassoil.The experimental materials of the topics is the compressed cotton stalks which is fromHebei and we improve the structure of existing system to improve the quality of the gasfrom gasifier and improve the quality of charcoal from carbonization furnace.The mainresearch results are as follows:(1)Improved the internal structure of the gasifier and carbonization furnace of theexisting biomass charcoal-gas cogeneration system.(2)Do experimental study of materials at different pyrolysis conditions in SK2-2-10resistance furnace,then the result is that the best carbonization temperature is450℃andthe char yield is40.4%.Then recording the analysis of carbon components,elementalcomponents and carbon calorific value,it showed that the heating rate has nothing to dowith the quality of carbonized charcoal production.(3)In the part of gasification experiment,when ER increased from0.2to0.5,thepre-heating rate of the gasification increased from24℃/min to39℃/min,the gasificationtime changed from70min to50min,the volume concentration of combustible gascomponents such as CO、H2dropped from14.98%and9.69%to11.8%and7.7%,thevolume concentration of CH4did not change when ER increased from0.2to0.5.Then thevolume concentration of non-combustible gas components such as N2、CO2ranged from 55.87%and14.54%to59.37%and18.76%,therefore the calorific value of gas changedfrom111.92MJ to90.45MJ;and the temperature of the oxidation zone can reach about900℃,the temperature of the reduction zone can reach about750℃under the experiments ofdifferent ER.(4)In the experimental part of charring,by calculating the calorific value at thetemperature around the best carbonization temperature which is450℃obtained from theresistance furnace,400℃,450℃,500℃is38.78MJ,43.95MJ,49.12MJ,therefore the heat ofgas from different ration gasification can be done during carbonization in carbonizationfurnace,then according to the principle of the best quality of gas,it can be concluded thatER=0.2,then we carried out this experiments at the equivalence ratio.The results showedthat:when the carbonization temperature increased from400℃to500℃,the ash and fixedcarbon in char increased from33.3%and48.5%to34.5%and52.6%,the volatile matter inchar fell12.9%from18.3%,the calorific value dropped19.35MJ to18.43MJ then roseto19.12MJ;these law corresponded to the law in resistance furnace.It can be concludedthat:the laboratory-findings of the equipment performance of the biomass charcoal-gascogeneration are good,and the best carbonization temperature is450℃.