Study On The Discharge Characteristics And Benzene Purification Application Of A Three-electrode DBD Device Powered By Two Generators

Dielectric barrier discharge(DBD)can stably generate reactive plasma at atmospheric pressure and normal temperature,and is widely used in material surface modification,biological sterilization,pollutant degradation and other fields.At present,the dielectric barrier discharge device is usually a two-electrode structure excited by a single generator(such as AC generator,pulse generator,etc.),and the electrode gap is small,so it is difficult to generate highly active plasma in a large space.In this paper,a three-electrode surface/volume DBD(SVDBD)device excited by two generators is studied to enhance the generation of plasma,reduce the onset discharge voltage of the discharge device,and improve its energy efficiency.In this paper,the electrical,optical and ozone generation characteristics of the dual-generator excited three-electrode S-VDBD device and the single-generator excited two-electrode volume DBD device were first compared.Then,the effects of voltage amplitude,dielectric thickness,discharge gap,strip electrode distance and electrode configuration on the discharge characteristics of the dual-generator excited three-electrode DBD device were investigated.In addition,using benzene as the target pollutant,the performance of the dual-generator excited three-electrode DBD device for benzene degradation was investigated.The main research results were as follows:Compared with the two-electrode volume DBD device,the onset discharge voltage of the three-electrode DBD device excited by two generators was lower;Under the same power frequency voltage,the dual-generator excited three-electrode DBD device generated more current pulses in a half cycle period,and the amplitude also increased significantly as well as the discharge power was higher.When the applied power frequency voltage was 16 k V,the volume discharge power and total discharge power of the dual-generator excited threeelectrode DBD device were 1.05 times and 1.16 times that of two-electrode volume DBD device powered by a power frequency generator,respectively.In addition,the dual-generator excited three-electrode DBD device produced higher ozone concentration and the energy efficiency was higher.With the increase of the high-frequency voltage amplitude,the onset discharge voltage of discharge device decreased,and the influence of the dielectric thickness on the discharge characteristics of the device also reduced;Moreover,the dual-generator excited threeelectrode DBD device can efficiently generate plasma in a large gap,expand the discharge space,and improve the gas processing capacity;In terms of ozone generation and energy efficiency,the use of strip electrodes as the ground electrode had more advantages than mesh electrodes.When the distance between the strip electrodes was 10 mm,the ozone generation was higher.The benzene degradation efficiency of the dual-generator excited three-electrode DBD device was significantly higher than that of the two-electrode volume DBD device.When the high frequency voltage was 1 k V and the power frequency voltage was in the range of 10-18 k V,the benzene degradation efficiency in dual-generator excited three-electrode DBD device was 7.23%～48.41%,which was 1.12～6.57 times that of power frequency excited twoelectrode DBD device;With the increase of voltage amplitude,the benzene degradation efficiency gradually increased,but the energy efficiency gradually decreased;When the discharge gap increased,the benzene degradation efficiency decreased,but the dual-generator excited three-electrode DBD device still maintained a higher benzene degradation efficiency under the large discharge gap,indicating that the device can improve the gas processing capacity.