The Effect of Voltage Pulse Shape on the Discharge Characteristics in the Packed Bed Reactor under Air and Nitrogen

Yao Li,Li Zhang,Dezheng Yang,Liang Qin,Wenchun Wang

doi:10.3390/app12042215

Abstract

In this paper, the packed bed dielectric barrier discharge (DBD) with needle-plate electrode configuration is presented to study the effects of electrical parameters, such as pulse duration and pulse rising and falling time, on discharge characteristics under air and nitrogen. The waveforms of the voltage and the discharge current, discharge evolution images, and the emission spectral of N2 (C3Пu → B3Пg) and N2+ (B2Σu+ → X2Σg+) are collected to investigate the discharge current, as well as the spatial distribution of the discharge modes and the reactive species in the packed bed reactor specifically. It is found that the pulse duration and pulse rising and falling time can regulate the discharge current. Firstly, increasing the pulse duration and the pulse rising and falling time can both increase the discharge duration. Secondly, the peak value of the discharge current has an obvious increasing trend with the pulse duration. Finally, the discharge start time can be delayed by increasing the pulse rising and falling time. A bright discharge channel is distributed at the top of the reactor, while the discharge is diffused at the bottom of the reactor. The generation of N2+ (B2Σu+) tends to depend on the existence of the streamer channel, and N2 (C3Пu) can be generated in the entire discharge area. In addition, the discharge operated in pure nitrogen can reach higher current values, a stronger discharge intensity, and longer existence time for the reactive species than in the air.

Highlights

The dielectric barrier discharge (DBD), which is formed by applying an alternating high voltage across two electrodes between which at least one dielectric appears, is a common way to generate non-thermal plasma [1,2]
The experiments are operated under pure nitrogen and air, which is mixed using nitrogen and oxygen with a ratio of 8:2 by adjusting the mass flow controller (MFC; S48−300, HoribaStec, Wuxi, China), and the purity of nitrogen and oxygen are both higher than 99.999%
The parameters of pulse voltage pulse have obvious on the discharge discharge the peak of current the discharge regulations on thecurrents

Summary

Introduction

The dielectric barrier discharge (DBD), which is formed by applying an alternating high voltage across two electrodes between which at least one dielectric appears, is a common way to generate non-thermal plasma [1,2]. The synergistic effects between the plasma and catalysis, which can improve the energy efficiency and the yield, make the PBR become the favorite discharge structure to generate non thermal plasma and be widely applied in the field of nitrogen fixation [8,9], volatile organic compound (VOCs) and toluene degradation [10,11,12], ozone generation [13,14], and CO2 conversion [15], etc.

Methods

Results

Conclusion