10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
Abstract View
Prevention of Back Corona Discharge Luminescence in an Electrostatic Precipitator Using Asymmetrical Rectangular AC Voltage
TOMOYA MITSUI, Koji Yasumoto, Akinori Zukeran, Takashi Nakano, Koyu Tsubouchi, Takashi Ogawa, Kanagawa Institute of Technology
Abstract Number: 146 Working Group: Combustion
Abstract An electrostatic precipitator (ESP) has been extensively used for removal particulate matter. However, when particles which has high resistivity deposit on dust-collection electrodes, back corona discharge is generated, and the dust-collection performance decreases. Therefore, the aim of this study is to prevent back corona discharge using asymmetrical rectangular AC voltage.
The experimental ESP consisted of a high-voltage application wire electrode (tungsten,Φ0.26) and a grounded plate electrode (90×150 mm) with the gap of 15 mm1). Calcium carbonate dust (thickness: 0.5 mm) was located on the surface of the grounded plate electrode. Symmetric or asymmetric rectangular AC voltages (voltages: ±9 kV) were applied to the wire electrode. The voltage waveform and the current waveform were measured, and a photograph of discharge luminescence on the surface of the dust layer was taken by a digital camera.
As a result, when the symmetric rectangular AC voltage was applied, the current for the time between 0 and 12.5 ms was approximately 0.01 mA due to corona discharge during the positive polarity. However, the current increased with elapsing the time after 12.5 ms due to back corona discharge. During the negative polarity, the tendency was similar with the positive polarity.
Therefore, an asymmetric rectangular AC voltage with the positive polarity application time of 7 ms and the negative polarity application time of 2 ms (the total period: 9 ms) was applied to the wire electrode to prevent the increasing the discharge current. The discharge current did not increase in both the positive and the negative polarities in the results.
The back corona discharge luminescence on the surface of the dust layer were taken by a digital camera, when the symmetric and the asymmetrical rectangular AC voltage were applied. The back corona discharge luminescence was observed on the surface of the dust layer in the symmetrical rectangular AC voltage. On the other hand, the luminescence was not observed in the asymmetrical rectangular AC voltage.
These results indicated that the back corona discharge was prevented due to applying the asymmetric rectangular AC voltage, whereby the discharge current did not increased.
1) T. Mitsui, S. Ito, K. Yasumoto, and A. Zukeran; Relationship between back corona discharge current and elapsed time in an electrostatic precipitator, European aero conference 2017, T108N0ae, 2017.