Investigation Of The Low NOX Burner With Crossrange Exhaust Gas Recirculation

A great deal of nitrogen oxide (NO_X) is produced in the coal combustion of power station boiler,and the NO_X causes serious damage to the ecological environment. low NO_X exhaustion emissions of large scale lean-coal boilers seriously exceed the emission control regulations established by our country, so it is necessary to be controlled instantly. According to the situation of our country, among all the measures used to control the NO_X emissions of the large scale boilers, the combustion modification measures, especially low NO_X exhaustion burner measures are preferred. In recent years, some research organizations and univesities in the country have developed many forms of low NO_X burner. But there is still much question that has not been settled because of the complexity of NO_X emission in the process of coal burner. Therefore going into the research of NO_X emission mechanism and low NO_X combustion experiment in the process of coal combustion has especially important significance. According to the situation that most of the utility boilers in our country are tangential firing ones,the paper systematically summarizes the generating characteristics of NO_X in the course of coal combustion and the characteristics of low NO_X burner in and out of country,put forward a designing idea which combines the horizontal bias combustion and backflow exhaust gas .Through adding high-velocity backflow exhaust gas at the dense side of horizontal bias burner and combining lateral backflow exhaust gas with coal powder at dense side,it makes the oxygen less when the dense side flow is buring and decreases the generation of NO_X. What's more,high-velocity backflow exhaust gas can help the dense-side flow to entrain more high temperature gas and make initial combustion more steady , consequently achieving the dual purpose of decreasing the generation of NO_X and making the combustion more steady. This paper deals with the experiments of the influence between the horizontal baffle and air flow, it also investigates the cold condition simulation tests about the influence between the gas horizontal crossrange air flow and the flow field near the burner' outlets. The results show us that,the deflection of the air flow direction has the linear relationship with the baffle installation angle; the horizontal crossrange air flow could enhance the air perturbation in front of the main nozzle, thus the mixing of the fuel inflammation field in front of the nozzle becomes stronger. The result of this paper could direct the reformation of low NOX emission system in the coal-fired boiler, and accelerate the domestic development of low NOX burner technology as well. Besides it would be helpful to the business development.