袋式除尘器滤袋接缝方法对PM_(2.5)过滤效率的影响

Influence of different bag joint methods on the PM_(2.5) filtration efficiency of the filter bag of the bag filter

针对袋式除尘器超低排放及对PM_(2.5)细颗粒物的捕集控制问题,选用分别经缝合、热熔两种制袋工艺制作的滤袋进行试验,探讨不同袋身接缝方法对袋式除尘器滤袋PM_(2.5)过滤效率的影响。结果表明:1 m/min过滤风速时,清洁状态下热熔滤袋对PM_(2.5)的过滤效率要比缝合滤袋高12.59%,而集尘状态下随滤袋表面粉尘负荷的不同,热熔滤袋对PM_(2.5)的过滤效率要比缝合滤袋高8.68%~11.18%;随过滤风速增加,缝合滤袋对PM_(2.5)过滤效率的衰减幅度要远大于热熔滤袋;滤袋表面尘饼的形成和分布的均匀性是缩小缝合滤袋与热熔滤袋间过滤效率差距的重要因素。

This paper is inclined to present a discussion of the ultra-low emission and the control of PM（2.5） fine particles by using a filter of bag filter. In order to pursue and clarify the PM（2.5） filtration efficiency affected by the different joining methods of the filter bags,we have experimented with two different filter bags and the different filtering approaches. That is to say,the former filter has been made by being stitched together whereas the latter has been made by hot-heated melting. In the experiment,we have adopted the ambient aerosol as the pollution source with the filtration efficiency of the two kinds of samples to be tested under the clean condition and the dust-collected condition. The results of the experiment show that,the PM（2.5） filtration efficiency of the hot melted filter bag accounts for 12. 59% higher than that of the stitched one under the clean condition in case the filtering velocity is set at 1 m/min. We have also found that,as the bonding area of the filtration of the stitched filter bag has increased by 1%,its PM（2.5） classification filtration efficiency would be reduced by0. 65%-0. 89% as compared to the melted filter one. Nevertheless,under the dust-collected condition,with the difference of the dust load on the filter bag surface,the PM（2.5） filtration efficiency of the hot melted filter bag has been found higher than that of the stitched one by 8. 68%,10. 73%,11. 18%,9. 91%when the dust load levels are kept at 200 g/m3,400 g/m3,600g/m3 and 800 g/m3,respectively. What is more,no matter whether under the clean condition or under the dust-collected one,the PM（2.5） filtration efficiency of the hot melted filter bag remains higher than that of the stitched one under the same experimental conditions. The main reason that accounts for this is that the bag pinhole of the stitched one is less efficient than that of the hot melted one. With the increase of the filtering velocity from1 m/min to 3 m/min,the attenuation rate of PM（2.5） filtration efficiency of the stitched filter bag accounts for 2. 73 times as that of the hot melted one. In addition,the formation and distribution uniformity of the dust cake on the filter bag surface serves as an important factor to narrow down the filtration efficiency gap between the two kinds of filter bags.