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基于Fluent平台,对410t/h燃煤锅炉选择性非催化还原(selective non-catalytic reduction,SNCR)系统喷射的尿素溶液液滴与烟气的混合过程进行数值模拟研究,同时探讨这一混合特性对脱硝率的影响。研究发现液滴穿透距离对于大空间的气液混合和烟气脱硝有重要影响,而对于给定的喷嘴它由溶液流量和液滴粒径确定;但是由于沿喷射方向存在较大的温度梯度,所以脱硝率还决定于液滴分布的当地温度。模拟结果表明在固定氨氮摩尔比下,喷射流量增大82%,脱硝率可提高8.8%,而随液滴粒径增大则先提高后降低;漏氨量随二者的增大均呈现降低趋势。另外,还将计算结果与实验测量数据进行了对比,以保证数值研究结论的可靠性。
Based on the Fluent platform, the mixing process of urea solution droplets and flue gas injected by a selective non-catalytic reduction (SNCR) system in a 410 t / h coal-fired boiler was numerically simulated, and the effect of this mixing property Effect of denitration rate. It has been found that droplet penetration has a significant effect on gas-liquid mixing and flue gas denitrification in a large space, which is determined by the solution flow rate and droplet size for a given nozzle; however, due to the large temperature gradient along the jet direction , So the denitrification rate is also determined by the local temperature of the droplet distribution. The simulation results show that the jet flow rate increases by 82% and the denitrification rate can be increased by 8.8% at fixed ammonia nitrogen molar ratio, and then increases and then decreases with the increase of droplet size; trend. In addition, the calculated results are compared with the experimental measurement data to ensure the reliability of numerical studies.