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 le
ngth. A 20 kHz sinusoidal voltage of 3-6 kV(PP) was used to generate the ba
rrier discharge for removal of NO and NOx from a simulated flue gas. The ga
p length was varied in the range 0.05-0.5 mm. The multipoint-to-plane geome
try was used as the electrode in order to lower the operating voltage. Usin
g the V-Q Lissajours' method, the discharge voltage across the gap was meas
ured during the discharge. The result shows that the average value of the r
educed 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. T
he NO removal, however, decreases with narrowing of the gap. This fact is c
onsidered to be caused by the fact that ozone generation decreases with red
uced electric field in a region of high E/n.