复合式静电除尘器滤料表面的电势特性

Characteristics of Surface Electric Potential of Filter Medias in Hybrid Electrostatic Filtration System

为改进复合式经典除尘系统,研究了针尖-极板系统内滤料表面电势分布以及电晕放电过程结束后滤料表面电势消逝规律。首先通过针尖-极板系统使得极板上的滤料荷电,在电晕放电过程结束后,再使用表面电位计测量滤料表面电势分布与衰减规律。测量的干净滤料包括PE（聚酯纤维）、Bag（袋式滤料）;带有颗粒层的脏滤料包括PE（聚酯纤维）。实验结果显示：对于2种干净滤料,其表面初始电势分布比较均匀,偏差〈15%;干净的PE滤料在45 s左右表面电势衰减至稳定值而Bag滤料15 s左右可以达到稳定,Bag滤料表面电势衰减速度快于PE滤料;当阴极电压在10～35 kV间变化时,干净PE滤料初始电势稳定在1 500 V左右而Bag滤料稳定在1 200 V左右,阴极放电电压的增加并不影响滤料表面电势初始值;对于带有颗粒层的PE滤料,颗粒层表面电势低且干净滤料部分电势高。研究结果可供复合式静电除尘系统的设计参考。

For improving the hybrid electrostatic filtration systems, we investigated the distribution and decay of electric potential on the surface of filter media after corona charge treatment in a needle-plate system. Firstly the dielectric filter media were charged in the needle-plate system. After the corona discharge ended, we measured the surface potential of the filter media with voltmeter to obtain the distribution and the decay feature. The tested filters included two clean ones, namely PE（polyester） and Bag filters, and a dirty one, particle-contaminated PE. The experimental results show that, the surface electric potentials of PE and Bag filters distribute relatively uniformly with their relative deviations below 15%, and trend to be stable after the two filters being exposed to air for 45 s and 15 s, respectively. That is to say, the surface electric potential decays faster in Bag than in PE. Increasing the corona discharge voltage from 12 kV to 35 kV, the initial surface electric potentials on the clean filters change barely, which are 1 500 V for PE and 1 200 V for Bag. Meanwhile, for the dirty PE, the surface electric potential is low at the particle-comprised cake layer but high on the clean media. The results can be used as a reference for designing hybrid electric filtration systems.