Optimization Of Multi-Needle To Plane Corona Discharge Device And Study On Formaldehyde Removing

The theory of NTP and the application background of electrical environmental engineering are introduced. The problems that lie in NTP application and the significance of overcoming these problems are discussed. Meanwhile, the mechanism of corona discharge has also been expatiated.With different spacing between needle and needle, and needles and plane, the experiments of both negative and positive corona discharge have been conducted. Meanwhile, the effects of the spacing on discharge energy density have been analyzed theoretically. Generally, discharge energy density reduces with increase of spacing between needle and needle, but it has small change when the spacing is in the range from 9mm to 20mm. Considering the stability of the discharge and the cost of manufacturing the discharge reactor, it is suggested that the optimum spacing is about 20mm. At the same time, discharge energy density reduces with increase of spacing between needles and plane, and the allowable discharge energy density is up to its maximum when the spacing is about 20mm.Formaldehyde removal experiment was carried with non-thermal plasma air cleaner. It can be seen from the experiment that formaldehyde removal rate goes down very fast with the decrease of formaldehyde density. One possible mechanism of formaldehyde removal has been developed. The main formaldehyde removal reactions are radical chain reactions induced by hydroxyl radicals. Oxygen is the main oxidizer.