Removal of NO and NOx using a multipoint-type dielectric barrier discharge at a narrow gap

In this paper we describe the dependence of NO/NOx removal on gap length by a multipoint-type dielectric barrier discharge in a region of short gap length. A 20 kHz sinusoidal voltage of 3-6 kV(PP) was used to generate the barrier discharge for removal of NO and NOx from a simulated flue gas. The gap length was varied in the range 0.05-0.5 mm. The multipoint-to-plane geometry was used as the electrode in order to lower the operating voltage. Using the V-Q Lissajours' method, the discharge voltage across the gap was measured during the discharge. The result shows that the average value of the reduced electric field increases up to 200 kV cm(-1) by shortening the gap, it has been clarified from the spectroscopic measurement that the electron temperature in the discharge plasma becomes higher by shortening the gap. The NO removal, however, decreases with narrowing of the gap. This fact is considered to be caused by the fact that ozone generation decreases with reduced electric field in a region of high E/n.