NOVEL SURFACE DISCHARGE NOX REMOVAL TECHNIQUE

A fundamental study of NOx removal using a surface discharge induced p lasma chemical process (SPCP) is presented. SPCP involves high-frequen cy surface discharge from strip-like electrodes attached to the surfac e of a ceramic tube to a film electrode attached to the opposite side of ceramic tube, This surface discharge has the following properties: (1) relatively low energy consumption for discharge generation, (2) op eration at atmospheric pressure, and (3) high-energy electrons, These properties show that SPCP is suitable for the removal of environmental pollutants such as NOx, SOx, and soot emitted from diesel engines and combustion furnaces. In this study, experiments on NOx removal were p erformed by introducing N atoms, which were produced by the addition o f N-2 into the surface-induced plasma, into an NO-containing gas. Furt hermore, the concentrations of N and O atoms were measured by ultravio let (UV) resonance absorption spectroscopy in order to investigate the reaction mechanism. The following results are obtained, (1) NOx remov al is observed by introducing N-2 gas activated by SPCP, and the amoun t of NOx removal increases with increasing N-2 concentration in the su rface-induced plasma, (2) NO reduction mainly proceeds according to th e reaction: N + NO --> N-2 + O. (3) The amount of O atoms generated ra pidly decreases due to the cyclic recombination reaction via NO2.