Numerical Simulation And Optimization Of The Denitrification Process Of SNCR In Cement Prcealciner

Now, along with strict NOx emission standards, reducing the gradual improvement of the emissions of nitrogen oxides is the focus of the researchers in the future for a long period of time. Precalciner is a key equipment to implement the low NOx technology. This paper makes theoretic researches on the process of SNCR in precalciner, aimed at offering theoretic references on the NOx emission reduction of the cement industry in our country, which shows a realistic significance.This paper built a numerical model of actual size precalciner by using CFD technology, combining qualitative and quantitative analysis, and then simulated coal combustion and calcium carbonate decomposition. On the basis of NOx formation and distribution analysis, this paper carried out the removing NOx numerical simulation by SNCR ways, and proceeded further optimization design by research of ammonia height, spray ammonia speed, spray ammonia Angle, ammonia nitrogen mole ratio,etc.The main conclusions are as follows:(1) For TDF-based 6000t/d of decomposition of the model furnace is more accurate and more reasonable distribution of income flow. Temperature, the decomposition rate of the system concide with the actual production needs;(2) Nitric oxide (NO) high concentrations focus on upper mantle in upper area area, the distribution of NO presented among low and high distribution characteristics of both sides. The generation of NO concentrated in the Z=8m high-temperature region where the coal-rich region. The NO generated in this region increases as the air eventually gathered in the upper edge of cylinder wall.and In the Z =8m spray them on a high ammonia can inhibit the formation of NO;(3) The different installation height of Reductant affects performance of denitration. It shows:When the jet spray height of 8m reducing agent, the reducing agent mixed with the flue gas is more fully conducive to the removal of NO;(4) The different ammonia molar ratio of Reductant affects performance of denitration. It shows:As with the ratio (NSR) increases, the average concentration of NO at the outlet decreases, and the change has slowed the trend, the average concentration of NH3 at the exit increases. When the jet spray height of 8m, To NSR =1.4 is suitable;(5) The different injection rate of reductant affects performance of denitra-tion.It shows:Height of 8m at the spray, when the NSR of 1.4 and the injection rate of 40m/s, the reducing agent mixed with the flue gas is more fully conducive to the removal of NO;(6) The different injection rate of Reductant affects performance of denitration. It shows:with the increase of reductant injection Angle, denitration rate are the first decline after rising trend. The optimal denitration rate can only be obtained with the optimized parameters as follows:the spray height of 8m, the NSR of 1.4, the spray rate of 40 m/s and at the jet angle of 60°.