Experimental Study And Numerical Simulation On A New Type Of Low-NO_X Swirl Burner

Among many techniques of NO_x emission control, the low-NO_x burner has the mosteconomical and best application prospect low-NO_x combustion technology. For solving theproblem that NO_x swirl burner is hard to fit to the various types of coal, this paperdeveloped a new low-NO_x burner, which meets the following advantages, stablecombustion of different coal types, simple system, easy operation, flexible adjustment andNO_x emissions reduction. Low-NO_x burner has theoretical significance and applicationvalue in engineering.In this paper, experiment of the prototype burner and a new low-NO_x swirl burnerswas carried out on a horizontal single-furnace system under the same experimental coal. Bymeasuring and analyzing the furnace temperature and gas component distribution, theresults showed that comparing to the prototype burner, when middle secondary air wasconcurrent, the ratio of NO reduction was largest, and the next was internal secondary airwhen it was concurrent, but outer secondary air rised instead when it was concurrent.Based on the correct simulation model verified by experiment, the hot and cold statesimulation research of a single prototype burner and a new low-NO_x burner were carried out.Analyzing the flow field, furnace temperature and gas composition dwastribution, thesimulation results showed that under burning the bituminous coal, relative to the prototypeburner, when middle secondary air was concurrent，the ratio of NO reduction was largest,the next was internal secondary air when it was concurrent, but outer secondary air was alsoconcurrent，the ratio rised instead. But under burning the lean coal, when internalsecondary air was concurrent，the ratio NO reduction was largest, the next was outersecondary air when it was concurrent，but middle secondary air was concurrent，the ratiorised instead.Finally, the furnace and30burners were integrated together as a computed fieldmethod. The combustion process of prototype burner and the new low-NO_x burners in theboiler were simulated under burning bituminous coal. The results showed that the simulation results worked better in responding the characteristics of the burner and werecloser to the real combustion of the burner in the combustion. The results also indicate thatwhen middle secondary air when it was concurrent，the ratio of NO reduction was largest,the next was internal secondary air when it was cocurrent，but outer secondary air reducedfew when it was cocurrent.