矿用除尘器逐排间歇清灰对呼吸性粉尘排放的影响及其控制机制

The morbidity of coal mine works’ pneumoconiosis remains very high for a long time in our country and the respirable dust in the biggest culprit. An effective method to control the respirable dust is to remove by filtration with the dust collector for coal mine. However, a lot of dust penetrates the filter cartridge and forms emission concentration peak during segmented stepwise cleaning stage, which is an important problem to restrict the respirable dust classification efficiency of the collector. The evolution of the flow field in filtration area and the migration of the dust fell off from cleaning will be mainly studied in this project. The pulse-jet flow characteristic, the two-phase flow with particles in filtration area, the rule and influencing mechanism of respirable dust emission will be researched systematically, including cleaning effect of pulse-jet in filter cartridge, deposition morphology of the re-adsorbed dust fell off from cleaning and the filtering effect of the formed dust cake; the evolution of flow field in the filtration area, migration rule of re-adsorption and sec-adsorption dust fell off from cleaning and their influence on respirable dust emission; build a comprehensive performance evaluation model for the dust collector system in the aspect of respirable dust and establish a new filter cleaning mode to reach a high efficiency for respirable dust control. This project will reveal the mechanism of increased respirable dust emission during segmented stepwise cleaning and provide theoretical and technical foundation for the scientific method with high efficiency for mine dust control.

我国煤矿尘肺发病率长期居高不下，其致病主要元凶是呼吸性粉尘（简称呼尘），矿用干式除尘器的过滤去除是井下控制呼尘的有效手段。然而，在矿用除尘器的逐排间歇清灰环节，大量尘粒会穿透滤筒，从而形成粉尘排放浓度峰值，这是制约矿用除尘器对呼尘分级去除效率的重要问题。本项目拟在逐排间歇清灰阶段，以过滤区域流场的演变和清灰脱落粉尘的运移为主要研究对象，对脉喷气流特征、过滤区域颗粒两相流流场、呼尘排放规律及其影响机制进行系统研究：滤筒内部脉喷气流的清灰作用、脱落尘粒发生再次吸附的沉积形态及所形成尘饼的滤尘效应；过滤区域流场的演变、清灰脱落尘粒发生再次吸附和二次吸附的运移规律及二者致呼尘排放特征；建立针对呼尘的除尘系统综合性能评价模型，并构建可实现呼尘高效控制的新型清灰模式。本研究将揭示矿用除尘器逐排间歇清灰期间呼尘加剧排放的作用机制，为采取科学手段以高效控制呼尘排放提供理论指导和技术支撑。

我国煤矿作业面粉尘浓度长期超标严重，导致矿工尘肺发病率一直居高不下，其中呼吸性粉尘是尘肺病的最大元凶。近年，我国新增煤工尘肺和矽肺占全国新发尘肺病94.2％，每年煤炭行业的尘肺病致死人数则已超生产事故的死亡人数。国家多部门出台了系列文件，表明了国家对矿尘危害的高度重视和加强矿尘治理的重大决心。矿用除尘器的应用普遍以经验型尝试为主，虽总粉尘除尘效率较高，但对呼尘的分级去除效率普遍不到80%，难以达到对浓度控制的标准要求。.本课题认为，清灰影响阶段的除尘效率是制约呼吸性粉尘达标排放的关键，为此，研究了矿用除尘器逐排间歇清灰对呼吸性粉尘排放的影响及其控制机制，主要内容有：.1）逐排间歇清灰策略及其性能的研究，定义并计算了清灰过程中各排滤筒脱落粉尘的再次吸附与二次吸附率，从残余过滤阻力的角度，正序清灰效果均优于逆序清灰（正序清灰残余过滤阻力小约25-30Pa），逆序条件对应的再吸率与二吸率均大于正序。正序和逆序清灰过程的平均再吸分别为14.75%和17.86%，二吸分别为4.62%和10.00%；.2）除尘器脉喷清灰影响阶段的粉尘分级排放特征，过滤除尘装置在稳定运行阶段TSP平均排放浓度为0.923 mg/m3，PM10为0.856 mg/m3，PM2.5为0.683 mg/m3。在脉喷清灰影响阶段，TSP、PM10、PM2.5具有类似的变化趋势，排放浓度均表现为先快速增加而后缓慢降低，持续时长约30~60s。；.3）研究黏性颗粒在滤料表面沉积的动态模拟及规律；滤膜泄漏对颗粒物过滤性能影响的研究；金锥褶皱滤筒脉冲喷吹性能的研究；除尘器全周期运行性能评价系统的软件开发。.研究揭示了矿用除尘器逐排间歇清灰期间呼尘加剧排放的作用机制，为采取科学手段以高效控制呼尘排放提供理论指导和技术支撑。相关成果发表论文11篇，其中SCI收录5篇，授权国家专利3项，登记计算机软件著作权2项。