| Pollutant NOX emission has great threat to the environment and our human health. It has practical significance to research the process of boiler combustion and NOX production and combustion technology of low NOX.Compared with tangentially fired boiler, though opposed firing boiler has unique advantages on slagging, stable combustion capability, flue gas temeperature difference and so on, it has more NOX emission. Though CFD method, the combustion process of the centrally fuel rich swirl burner and the boiler are simulated, and how to low NOX emission of them are studied. The major work of this paper are as followings.1.With a 300MW opposed firing wall boiler which use centrally fuel rich swirl burners as research object, the combustion process of the centrally fuel rich swirl burner is simulated,. The results show that the burner performance well in coal ignition, coal combustion and NOX emission when distance between concentration rings with the burner port is 325mm, the distance between concentration rings is 80mm, coal particle size is about 120μm.2. Based on study of the single burner, the 300MW opposed firing boiler model is set up. The results show that when the rate of primary air is 25%～30%, the rate of inner secondary air is 30%～40%, the rate of outer secondary air is 60%～70%, the stoichiometric is 1.2, the boiler has better NOX reduction efficiency and the combustion efficiency.3. For the boiler using the centrally fuel rich burner, the burners burn separately, recirculation zonse make coal fire timly. The tempateture field distribute reasonablely.4. Using the lean-rich combustion and staged combustion technology, the boiler has lower NOX emission.5. Under the combustion efficiency premise, though improving the stucture of centrally fuel rich burner and operating conditions of the boiler, the NOX formation of the boiler reduce significantly.The innovations of this paper are as followings:Though CFD method, the combustion process of the centrally fuel rich swirl burner and the boiler are simulated, under the combustion efficiency premise, the way to low NOX formation is given. |
