煤粉料仓通气下料流动行为

Flow behavior of aerated discharging of pulverized coal from hopper

在可视化有机玻璃料仓系统上对煤粉下料过程及其特性进行了实验研究。研究表明,煤粉介质粒径小、比表面积大,属于黏附性非自由流动粉体,下料流动困难;料仓通气技术可以显著改善煤粉流动性从而促进料仓下料,但过量通气反而会抑制煤粉下料。通过分析下料过程中料仓壁面的压力信号,揭示了料仓压力分布特性,分析了超侧压现象并定义了压力转换面。实验发现,通气可以在一定程度内减小超侧压幅度,扩大煤粉流化疏松区域,提升转换面高度。此外,研究还发现通气下料过程中存在气体穿透现象,穿透临界高度随通气量的增加而提高,并且穿透后煤粉下料流率降低。

The process and characteristics of pulverized coal discharge from a visualized plexiglass hopper were investigated. The discharge of coal was difficult due to its small particle size and large specific surface area with strong agglomeration and poor flowability. The addition of gas could improve the flowability of coal as well as increase discharge rate, however excess aeration would decrease discharge rate. The features of pressure distribution were revealed by analyzing the pressure signals from hopper wall during discharge, and overpressure phenomenon was analyzed and pressure transition surface was defined. The quality of discharge such as reduction of overpressure, extension of loose area of coal and increase of height of transition surface could be improved by aeration to some extent. In addition, gas penetration occurred during aerated discharge. Increase of gas flow rate increased the critical height of gas penetration and discharge rate of coal decreased after gas penetration.