中速磨煤机内原煤研磨过程的试验研究

Experimental study on breakage process of raw coal in medium speed mill

基于MPS型中速磨煤机的结构特点和研磨机理,设计制造了实验室辊磨试验系统,用于模拟、研究封闭磨煤机内物料的粒度减小与能量消耗问题,分别利用3组窄粒级煤样对加载力、磨盘转速及填充率对颗粒破碎行为的影响进行考察,同时利用功率测量仪监测磨煤机的研磨能耗。研究揭示了不同试验条件下研磨能耗随时间的变化规律;经典的煤粉细度—能耗数学模型能够很好的描述仅加载力或填充率变化的试验过程,拟合精度R^2大于0.96;不同磨盘转速条件下煤粉细度—能耗曲线出现波动,导致模型不能使用。基于颗粒破碎能量效率随着粒度的变化呈正相关变化,将粒度嵌入经典破碎模型中,实现在相同磨盘转速条件下,针对不同粒度、加载力和填充率时能量—粒度减小过程的表征。

Based upon structure characteristics and grinding mechanism of MPS medium speed mill,a lab-scale roller-race mill was designed to simulate reducing particle size and energy consumption in closed coal mill.The authors inspected influences on particle breakage behavioral of loading force,millstone rotate speed and filling rate of three narrow fraction coal sample,meanwhile,monitor grinding energy consumption of the mill by using power measurement.The results showed changing rule between grinding energy consumption and time in different experimental conditions.In the rule,the classical fineness of pulverized coal energy consumption mathematical model could describe the experimental process that only changing the loading force or filling rate with R^20.96 fitting precision,the energy consumption curve of fineness of pulverized coal was fluctuated with different millstone rotate speeds which leads to the model out of commission.According to positive correlation between particle sizes and energy efficiencies of broken particle,the authors implanted particle size into classical breakup model which achieving process representation of energy particle reduction with various particle sizes,loading forces and filling rates under same millstone rotate speed.