煤矿综放工作面高压雾化降尘对粉尘颗粒微观参数影响规律分析

Influence regulations analysis of high-pressure atomization dust-settling to dust particle's microscopic parameters in fully mechanized caving coal face

喷嘴高压雾化降尘是综放工作面首要防尘方法。对于喷雾前后粉尘浓度的降低情况研究较多,而忽视了喷雾前后尘粒的粒度、粒径分布、形状系数、比表面积等颗粒微观参数的变化情况。采用显微颗粒图像分析法对生产现场喷雾降尘前后各主要作业地点的粉尘进行了微观参数测定。结果表明：喷雾降尘前后,各采样点的D10,D25,D50,DP,XNL,XNS一般在1.0～7.0μm之间小幅度变化,但D75,D90,D100,XNV,XLS,XLV,XSV,XPV却在3.3～56.8μm之间大范围变化;粉尘粒度变化与喷嘴雾化效果的关系为雾化效果越好,粉尘粒度则变得越大,反之亦然;喷雾降尘对粉尘的形状系数和比表面积影响较小;雾化降尘前后,工人主要作业区域呼尘所占比例及其4种粒级频率分布、累计分布较大幅度降低;除粉尘浓度外,还应将粉尘粒度及不同粒径粉尘颗粒的频率分布与累计分布的变化情况作为考核喷嘴雾化降尘效果的重要依据。

Fully mechanized caving face is a main dust producing place in a coal mine. Currently, high-pressure nozzle atomization is the most important dust-settling method in fully mechanized caving faces. However, for a long time,it is only concerned about the reduction of dust concentration before and after spray, while the changes of particle parame- ters are ignored, such as particle size, size distribution, shape factor, and specific surface area, etc. Hence, the micro- scopic parameters of dust at all major working locations before and after spray were measured through microscopic par- ticle image analysis. The results show that before and after spray, D10, D25, D50, DP, XNL ,XNS have relatively little varia- tion in each sampling point, generally between 1.0 - 7.0 μm, however, D75, D90, D100, XNV, XLS, XLV, XSV, XPV vary sharply, usually between 3.3-56.8μm. The relationship between the dust granularity change and the nozzle atomiza-tion effect is that the better atomization can be, the larger dust particle size will become, and vice verse. The spray af- fects the dust shape factor and the specific surface area to a small degree. Before and after spray, in the main working locations the proportion of respirable dust and the frequency distribution, cumulative distribution of four size fractions of respirable dust particle sizes decrease to a large degree. Except for the dust concentration, the dust granularity and the changes of frequency distribution and cumulative distribution of dust with different particle size should also be re- garded as an important basis for assessing the dust-settling effect of nozzle atomization.