Study On The Characterization Of A Low NOx Swirling Burner

With the rapid development of Chinese power system, the problem of pollution made by coal combustion is becoming more and more serious. Reducing pollutant emissions will be a challenging task in the future. NOx is one of main pollutants during coal combustion, which has caused serious threat to the environment. Nowadays, more and more attentions have been paid to NOx emission controlling. Therefore, research and development of new swirl burners which suit for lean coal and anthracite coal combustion with denox feature are significant for the safety and low NOx emission of large scale power plants.Firstly, this paper summarized the main methods of controlling NOx emission and the NOx formation mechanisms. The current swirl burners were introduced, too. Then, the affecting facts of low NOx combustion performance on swirl burners were analyzed. That provided the basis for the research and optimization of low NOx swirl burner.The cold-state experiments and numerical simulation of a type of swirl burner were carried out. The effects of the center bluff body,the angle of primary air outlet, the angle of inter-second outlet and the angle of outer-second air outlet on the flow field were discussed. Then, the theory of the numerical simulation of the theory was introduced, focusing on the standard k-εmodel, RNG k-εmodel, and Realizable k-εturbulence model. The results showed that Realizable k-εmodel was the most reasonable model. With Realizable k-εmodel for numerical simulation on the burner, the aerodynamic characteristics at different angle of inter-second air outlet and outer-second air outlet were discussed, which verified the results of cold condition experiment.Further more, a modified swirl burner was developed based on the results of cold-state experiments and numerical simulation. The burner's aerodynamic characteristics at different second air were discussed.Finally, the hot-state experiments were carried out on a horizontal single- furnace system. Thermocouple thermometer and flue gas analyzer were used to quantify the temperature and NOx distribution. And, the results of hot-state experiment were verified through the numerical simulation of the temperature and NOx distribution at different inter-second air and outer-second air.