Experimental Study On Premixed Gas Combustion Process In Fire Bed

With the rapid development of industry,the control of nitrogen oxide emissions has become an urgent matter.Premixed combustion,as a low-NOx emission combustion method,is widely used in civilian burners,industrial boilers,and utility boilers.There are two types of commonly used premix burners,including water-cooled premix burners and metal fiber burners,both of which are prone to flashback and tempering problems.At the same time,water-cooled premixed burners are mainly used in households at present.It also causes excessive exhaust heat loss;metal fiber burners,however,can only operate at high excess air ratios,increasing the heat loss from the exhaust fumes.In order to improve the stability and economy of premixed burners,a premixed gas fired burner with alumina hollow spheres as inert filler was designed and manufactured to compensate for the deficiency of existing burners.Through the Fluent simulation of the cold flow field of the combustion chamber,it is found that when no alumina hollow spheres are laid,many vortices are generated in the flow field in the burner,which is extremely unfavorable to the premixed combustion;after adding the alumina hollow spheres,the burners The inner flow field is uniform and stable,and the outflow velocity of the hollow sphere is more appropriate.Designed and constructed a fire bed premix gas combustion test bed including gas-air premixed system,flue gas cooling system,furnace negative pressure control system,flue gas composition measurement system,etc.The parameters of nitrogen oxides,oxygen and carbon monoxide in the flue gas under different conditions were determined under the hot conditions,and the relationship between the premixed ratio and the emission of nitrogen oxides was fitted.The test results show that this is an effective combustion method,and the test results provide reference for designing large-scale gas fired bed premixed burners.