提高中速磨煤机出力的数值模拟与试验研究

Simulated and Experimental Research to Improve the Capacity of Medium Speed Mill

针对ZGM113G型磨煤机磨制褐煤时,出口温度低、通风阻力大和磨煤单耗高等问题,提出了加装切断分离器阻断粗粉内循环气流场,加装喷嘴扰动风装置让合格煤粉及时分离的改造方案。计算结果认为,改造后磨盘顶部的气流速度明显增加,扰动增强,使磨盘表面聚集的煤粉减少;分离器入口的气流速度更加均匀,进入分离器煤粉浓度明显增大。改造后磨制褐煤时的性能测试数据表明,在煤粉不变粗的前提下,改造后的磨煤机最大出力从60 t/h提高到70 t/h,同时磨进口风量和出口风温均明显提高,磨煤单耗平均下降2.41 k Wh/t煤。

The ZGM113 G type-pulverizer results in a number of problems when pulverizing lignite coal, such as low outlet temperature, large air pressure drop and high power consumption. In order to solve these problems, a reforming plan is proposed by adding separators and nozzles. By this way, the internal flow of coarse powder is blocked and the qualified coal powder is separated in time.The numerical simulation indicates that significant changes of flow state in the pulverizer after reforming. Firstly, less coal powder concentrates on grinding disc because of higher air flow rate.Secondly, more coal powder enters the separator because of more uniform air flow rate at its inlet. The performance test result shows that the pulverizer capacity increases from 60 t/h to 70 t/h, and the power consumption of pulverizing 1 ton coal decreases by 2.41 k Wh, without obvious weaken of the coal powder fineness and air temperature at pulverizer outlet.