多针-板高压脉冲放电反应器结构优化及降解甲醛的实验研究

Structure Optimization of Multi-needles-plate High-voltage Pulse Discharge Reactor and Formaldehyde Degradation

为了进一步提高脉冲放电能量注入效率达到有效去除有机污染物的效果,对自制多针-板高压脉冲放电反应器的电极结构配置优化进行了实验研究。通过研究不同针板间距和针针间距对脉冲功率密度的影响来优化了电极结构配置,在此基础上进一步研究了不同电参数和气体参数对脉冲放电能量注入效率和甲醛降解率的影响规律。结果表明：随着针板间距的增大,对应的脉冲功率密度随之减小,脉冲放电最大可注入的脉冲功率密度在针板间距为20 mm时达到极值;当针板间距为20 mm时,随着针针间距的增大,对应的脉冲功率随之增大,脉冲功率密度随之减小,当针针间距增大到20 mm时脉冲功率增幅已经很小,但针针间距在15~20 mm范围内时脉冲功率密度变化很小,兼顾放电稳定性和脉冲功率密度,针针间距为20 mm较优。在优化的反应器结构下进行的甲醛降解实验研究发现：当脉冲峰值电压为17 k V、脉冲重复频率为40 Hz、气体体积流量为0.3 L/min且反向进气时,该实验的甲醛降解效果达到最佳,甲醛降解率和能量注入效率分别为87.1%和3.19 g/（k W·h）。

In order to further improve the energy injection efficiency of pulsed discharge to remove organic contaminants effectively, we experimentally studied the optimization of the electrode structure of a homemade multi-needles-plate high-voltage pulse-discharge reactor, as well as the influences of electrical parameters and gas injection parameters on the energy efficiency and formaldehyde degradation. The optimization was based on analyzing the effect of needle-plate spacing and needle-needle spacing on the energy density, The results show that the power density decreases with increask ing needle-plate spacing, and the allowable discharge energy density reaches its maximum when the spacing is 20 mm. With needle-plate spacing of 20 mm, the disctiarge power increases with increasing needle-needle spacing but the power density decreases; when the needle-needle spacing is 20 mm, the discharge power barely keeps increasing, while the power density slightly varies when the spacing is within 15-20 ram. Therefore, when both discharge stability and power density are taken into consideration, the optimal needle-needle spacing is 20 mm. With the optimized reactor configuration, degradation experiments of formaldehyde were conducted. It is found that, with pulse peak voltage of 17 kV, pulse repetition frequency of 40 Hz, and reversed airflow at 0.3 L/min, the reactor has its best formaldehyde degradation rate, which is 87.1% with energy injection rate of 3.19 g/（kW.h）.