LIF diagnostics of ground-state NO density in a reactor with streamer corona plasma

Abstract

Laser-induced fluorescence (LIF) has been proved to be a useful diagnostic method for in-situ observation of the discharge-induced plasma-chemistry processes responsible for NO (NO + NO2) decomposition occurring in nonthermal plasma reactors. In this paper a method and results ofthe LIF measuring ofthe two-dimensional distribution of the ground-state NO molecule density inside a DC positive streamer corona reactor during NO removal from a flue gas simulator [NO (200 ppm)/air] are presented. Either a needle-to-plate or nozzle-to-plate electrode system, having an electrode gap of 30 mm was used for generating the steamer corona in the reactor. For the LIF monitoring of the ground-state NO molecules, NO molecules were excited with a laser line of a wavelength of 226 nm. The LIF monitoring ofNO molecules was carried out under the steady-state DC corona discharge condition. The obtained results showed that the corona discharge-induced removal of NO molecules occurred not only in the vicinity of the plasma region formed by the corona streamers and the downstream region ofthe reactor but also in the upstream region of the reactor. This information is important for optimizing the non-thermal plasma reactors used for NOx abatement.