Experimental Study On Flameless Combustion Of Biomass Gasification Derived Gas

As a big country of energy production and consumption,China uses fossil fuels as the major energy source,which not only faces with issues of energy shortage and maldistribution of resource,but also brings environmental problems as haze.Compared with fossil fuels,biomass gasification derived gas（BDG）has advantages of clean and renewable.Meanwhile,the biomass is abundant and widely distributed.Using BDG for energy source can both reveal the pressure of energy shortage and protect the environment.At the moment,although being the main approach of BDG utilization,conventional combustion is still unsatisfactory in efficiency and emission.The primary reason is BDG characteristics that complex composition,low calorific value and amounts of impurities,which cause problems as unstable combustion,low efficiency and heavy pollution.Flameless combustion plays a significant role in the mitigation of combustion-generated pollutants whilst meeting thermal efficiency needs,and it has excellent application prospects in BDG utilization.In this study,BDG’s molecular weight,density,caloric value,theoretical air requirement,Wobbe index and burning velocity is analyzed.Through the results,a new type of BDG flameless combustion device is independent designed to meet the experimental needs.The device has advantages of small occupied area,high automaticity and convenient for transportation and installation.In the experiment,the feasibility of BDG flameless combustion was confirmed by using the independent designed BDG combustion device.The results show that BDG can achieve flameless combustion mode by strong jet entrainment and turbulent.Uniform temperature distribution without hot spots is found inside the furnace.The interior of the furnace is translucent and the flame front is invisible.Finally,the influence of preheating temperature,equivalence ratio,different dilution components on temperature distribution in the furnace,extent of combustion and NO_X emissions are investigated.The results show that the preheating temperature has the most significant influence on the temperature distribution in the furnace.Increasing the preheating temperature,the equivalence ratio and the CO₂ volume fraction in the dilution components can all contribute to the combustion.The NO_X emission has a correspondingly increase with the rise of the preheating temperature,and decreases with the rise of the equivalence ratio,but the intensity of the NO_X emission variation is extremely slight,which limited by the low level combustion temperature in the furnace.