间隙距离对DBD脱除NO_x的影响及机理分析

Effect of Gap Distance on Nitrogen Oxides Removal by Dielectric Barrier Discharge and Its Mechanism Analysis

为了探讨气体间隙对介质阻挡放电(DBD)脱除氮氧化物(NOx)的影响,运用气体放电理论和波尔兹曼输运方程计算了流注通道内空间电荷屏蔽作用下间隙距离与折合场强、折合场强与电子平均动能的关系。计算显示当间隙距离≥3mm时,间隙距离的改变对折合场强和电子平均动能的影响不明显。进行了不同间隙距离DBD脱除NOx的实验研究,结果表明:在实验范围内(5～7.5mm),改变间隙距离基本不影响脱除NOx的能耗。鉴于提高间隙距离有助于提高设备的处理能力、降低初投资,在利用DBD脱除烟气中的NOx时,可适当提高间隙距离,原因是在可能得到工业应用的间隙距离范围内(1～5cm),间隙距离的改变对电子平均动能的影响微弱。

To study the influence of gap distance on nitrogen oxides （NO,） removal by dielectric barrier discharge （DBD）, the function relationships between the gap distance, the space-charge shielded reduced field inside the streamer channel, and the electron mean energy in the nonthermal plasma are calculated by using the gas discharge theory and the appropriate Boltzmann transport equation. Calculations indicate that altering the gap distance has little effect on the reduced field and the electron mean energy when the gap distance is equal or greater than 3 mm. Different gap distance experiments were conducted using a concentric cylinder double dielectric-barrier discharge reactor. Results show that within the experimental range （5-7.5 mm）, the gap distance almost does not affect the electrical energy consumption for DBD processing of NO,. Considering the fact that raising the gap distance could expand the disposal capacity of equipment and decrease the initial investment, a relatively larger gap space can be adopted during DBD processing of NOx. The reason is that within the gap distance range （ 1-5 cm） of the potential commercial application, the effect of the gap distance on the electron mean energy is weak.