双极荷电静电除尘器收集高比电阻微尘的实验

根据粉尘层反电晕现象分析,提出在接地收尘极板上布置芒刺反电晕放电极的双极电晕静电除尘器,这种双极电晕静电除尘器能避免粉尘层的反电晕。在平均场强约3.4kV/cm时,采用粒子图像测速仪(PIV)测得电场内正、负离子风的核心区风速约2m/s。实验表明,离子风对收集微细粉尘有很好的促进作用。在常温常压下,平均场强为3.4kV/cm、气流速度在0.5～2.0m/s的范围内,对质量中位径为0.159μm、比电阻为2.4×1014Ω.cm的硅微粉的电除尘效率测定结果表明,双极荷电静电除尘器的除尘效率高于单极荷电静电除尘器。观察发现,由于接地芒刺的存在,即使对于比电阻高达2.4×1014Ω.cm的硅微粉,沉积在双极荷电静电除尘器收尘极板上的粉饼没有出现反电晕。

EXPERIMENT ON THE COLLECTION OF FINE DUST WITH HIGH RESISTIVITY BY A BIPOLAR DISCHARGING ESP

A new electrostatic precipitator (ESP) for avoiding the back corona of the high resistivity dust layer is developed by fixing the barb nail discharging electrodes on the grounded plate electrodes based on the analysis of the phenomenon of the back corona of the high resistivity dust layer deposited on the grounded plate electrodes.Therefore, this ESP becomes a bipolar discharging ESP because the negative and positive ions are generated simultaneously by the high voltage discharging electrodes and the grounded barb nail discharging electrodes respectively.The ionic wind is measured by a particle image velocimetry(PIV)because the ionic wind plays an important role in collecting the fine dust with high resistivity.The positive and the negative ion wind velocities in core area are about 2 m/s when the distance between the opposite electrodes is 100 mm at the voltage of 3.4 kV.In our comparison experiments,the overall efficiency of the bipolar discharging ESP for collecting the silica flour with 0.159 μm mass median diameter is higher than that of the unipolar discharging ESP at the mean electric field of 3.4 kV/cm at the room temperature and pressure.The experimental observation shows that the there is no back corona in the bipolar discharging ESP even when the very high resistivity silica flour (2.4×104Ω·cm) is used.