| Biomass resource is abundant, especially straw, firewood and wood resources，inHunan province. Although biomass fuel could be converted to biomass gas to improvethe utilization efficiency of biomass energy by diversified domestic biomass gasifier.As generally using air as biomass fuel gasification agent, the gasification reaction gascontains many impurity components such as nitrogen, tar and ash. And this results inthe low content of CO, H2and CH4in biomass gas, and the combustion heat valuealso become low. Therefore, a high fuel heat value gas biomass gasification furnacewhich uses air-water vapor as gasification agent was designed, and further testing andresearch were conducted to find how to distribute two gaseous fuel. It is of greatsignificance to provide a reference for further optimizing the two gasification agentdistribution parameters, enhancing the burning biomass gasification gas volumeconcentration of the main ingredients gas and its combustion heat value, and toimprove the efficiency of biomass energy utilization.The gasifier researched is the fixed bed double chamber structure up-draftgasifier, which takes the straw as the fuel, and the air-steam as gasifying agent.According to the combustion reactions, fluid dynamics and heat transfer principles, ahome high calorific value gas of biomass gasification system was designed. And thethree parameters of the air inlet flow, steam entrance location and its entrance flowwere optimized. Finally, the test platform was built to test and study the influence ofthe type and the flow of gasification agent on the main component content andcalorific value gas.The main contents and findings of this study are as following:（1）According to2days’gas requirements for the current rural4to6members offamily, a system of dual-chamber structure fixed bed up-draft domestic high calorificvalue fuel gas biomass gasifier was designed. The gasifier has a ‘#’ shaped porous air supplying device, water vapor supplying devices which can adjust the flow, furnacegrill, and furnace cover device.In addition, each time when a gasification furnace runs,another furnace plays the role of filtrating and purifying gas fuel to improve the airquality.（2）It takes the operating gasifier of the double furnace structure as thegasification reaction numerical calculation region. Then the principle of biomass fuelcombustion and gasification reaction was used to analyze the volume concentration ofCO, H2and CH4in biomass gasification reaction, and the calorific value ofcombustible gas. The Fluent computational fluid software was used to carry on thenumerical simulation for studying the influence of the parameters, such as the heightbetween steam entrance and the grate in gasifier, the water vapor inlet flow and airinlet flow, on gas heat value and the volume concentration of the main component inburning biomass gas. A reasonable orthogonal experiment was designed andconducted to seek the three parameters’ optimum value, and to optimize theparameters which influence the volume concentration of CO, H2and CH4, and thefuel gas calorific value.（3）The results showed that the agent of air-steam was used to improve biomassgas calorific value. Among the three influence factors, the steam inlet height was thebiggest, then air inlet flow, and the smallest was steam inlet flow. According to theorthogonal experiment and the experiment data, when the steam gasification agententry position h is175mm, air inlet flow V0is0.92m3/h, steam inlet flow Vsis1.33m3/h, the volume concentration of CO, H2and CH4in biomass gas is the highest,and biomass fuel gas combustion heat value（Q=10.46MJ/m3）is the biggest. |
PDF Full Text Request