Numerical Simulation Of Low NO_x Emission In Gas Reburning

Nitrogen oxides(NOx) pollution is one of the atmospheric pollution,and it is a threat to environment,climate and human health.With the development of society,the pollution of NOx is becoming more and more serious.The economic and effective reburning technology has been concerned by scholars.However,natural gas has advantage of small investment,low operation cost,high efficiency of stock and so on,so it has great practical value in engineering.Based on inducing,conclueding and analysising the previous work,the paper takes a simplified unit furnace as study object, FLUENT software can be used to simulate the combustion in the furnace.Establish mathematic models of the furnace combstion.The gas-Phase turbulent flow was deseribed by Realizable k-? iturbulence model,component transport model was employed to deseribe the proeess of gas-Phasce ombustion; radiation heat transfer was depieted by P-1 model,the post-treatment method was employed to calculate the generation and reduction of NO.Based on the above model,the simulation on the process of natural gas reburning was performed.The results give out the distribution of velocity,temperature,reaction and the concetration of components and NO in furance. The data of the experimental group were compared,and the accuracy of the numerical simulation was obtained.In this base,the paper analyzed the effects of excess air coefficient of the main combustion zone,length of main combustion zone,reburning zone length,reburning ratio on the output NO concentration.The simulation resuils conclued:the excess air coefficient in the main combustion zone is generallyl.05;length of main combustion zone is not suitable to be too long or too short,the best length is 80mm;the inerease of reburning zone length is benefieial to reduce NO emission but against the combustion of primary combustion zone,considered comprehensively,the best value is 80mm;the best range of reburning ratio is 10%-20%.The numerical simulation study of this paper gives out the furnace combustion charaeteristics of natural gas reburning condition,provides significance to the experiment and reference for actual engineering application.