脱硫废水喷雾塔粘壁和颗粒干燥特性分析及优化

Study on wall sticking and particle drying characteristics of desulfurization wastewater spray tower and the optimization

某350 MW机组2200 kg/h脱硫废水喷雾塔运行时经常出现粘壁现象,对该塔进行数值模拟研究,探讨了喷嘴中心距、雾化角对喷雾塔黏壁及出口粒子温度和含水率均匀性的影响。研究表明:在设计工况下,壁面处颗粒最大含水率自塔顶向下,先增大后减小,在17.5~21.2 m壁面处颗粒最大含水率超过5%,粘壁概率极大;优化工况为喷嘴中心距1.18m、雾化角41.43°;与设计工况相比,优化工况的壁面含水率自上而下平均下降了4.36%,出口截面颗粒含水率和温度标准偏差系数C_(W)、C_(T)分别降低了4.9%和8.3%,出口颗粒含水率平均值和最大值分别下降了4.5%和3.9%,优化效果显著。

Wall sticking phenomenon usually occurs during drying of desulfurization wastewater in a 2200 kg/h spray tower of a 350 MW unit,affecting the unit normal operation.Numerical simulation is conducted on this spray tower.The influences of the distance from the center of the nozzle plane to nozzles and the atomizing angle on the wall sticking and the uniformity of outlet particles temperature and moisture content are discussed.The research manifests that,under the design condition,the maximum moisture content of particles at the wall surface increases at first and then decreases from the top of the tower down.The maximum moisture content of the particles at 17.5~21.2 m of the wall exceeds 5%,implying the wall sticking probability is extremely high.The optimal analysis shows that the most appropriate distance from the center of the nozzle plane to nozzles is 1.18 m and the most appropriate atomization angle is 41.43°.Compared with the design condition,the optimized wall moisture content averagely declines by 4.36%from top to bottom,the moisture content C_(W) of outlet cross-section particle and the temperature standard deviation coefficient C_(T) decreases by 4.9%and 8.3%,respectively,and the average and maximum moisture content of outlet particles decreases by 4.5%and 3.9%separately,indicating the optimization effect is dramatic.