Study The Process Of Wire-to-Plate Pulsed Corona Discharge By Spectroscopy

Pulsed corona discharge is a new technique for multi-pollutants removal in flue gas. In the process of pulsed corona discharge, the OH radical production; the spatial distribution of NO in the electric field and correlative are discussed in detail, and to support the research of the technology for the removal of multi-pollutants by pulsed corona discharge as references. The emission spectroscopy and laser-induced fluorescence techniques have been used to diagnose the OH etc. active species produced by pulsed corona discharge at atmospheric pressure. The main results presented in the dissertation have been summarized as follows:In order to get extensive knowledge of wire-to-plate pulsed corona discharge reactor, emission spectrums of OH(A2Σ+→X2Π) is detected in humid Ar pulsed corona discharge, the existence of OH radical in pulsed corona discharge is verified. The influence of different diameters of wire electrode, different wire-to-plate and wire-to-wire spacings, OH radical generations in different O2 concentration were experimentally investigated under atmospheric pressure based on emission spectrum, the spatial distribution of OH radicals in the electric field is also discussed in detail. The results showed that:OH radicals decrease along the X-axis, the radius of active volume is approximately 20mm; showed a trend of first increase and then decrease along the Y-axis, the activation radius is more than 30mm; in the direction of Z-axis, no essential difference occurs. OH radical has small change as the diameter of wire electrode is shorter than 2mm; with a sharp decline as the diameter continue to increase. OH radical emission intensity decreases as wire-to-plate spacing increasing, increases as wire-to-wire spacing increasing and decreases as O2 concentration increasing.The emission spectrum of NO(A2Σ,0)→NO(X2Π,2-6) produced by pulsed corona discharge in a wire-to-plate electrode configuration has been recorded. The influence of the peak voltages, the discharge frequencies, the NO concentration on the emission intensities are investigated. The spatial distribution of NO in the electric field is also discussed. Experiments'results proved the emission intensity of NO increases as the peak voltages and frequencies of pulsed corona discharge increasing. The emission intensity of NO has small change as the frequencies of pulsed corona discharge changes in higher range. The emission intensity of NO decreased significantly as the NO concentration decreasing, and disappeared as the concentration less than 200ppm. The emission spectrum of NO focused on the 10mm radius of the region along the X-axis and Y-axis, and NO fluorescence signal disappeared over the region. This experiment can only reflect the spatial distribution of excited NO, new detection methods must be selected to accurately know the spatial distribution of NO. It is found that the energy needed to stimulate the NO is higher than the OH radical.To study the spatial distribution of OH radicals and the influence of different O2 concentration on OH radical generation were experimentally investigated under atmospheric pressure based on laser-induced fluorescence. It is found that OH radicals decreasing along the X-axis, the activation radius is approximately 30mm; showed a trend of first increase and then decrease along the Y-axis, the activation radius is 10mm; and OH fluorescence signal disappeared over the region. OH radical concentration showed a trend of first increase and then decrease as oxygen concentration increasing, the largest OH concentration appear when the oxygen concentration is 10%, and OH radicals disappeared when the oxygen concentration greater than 40%. Select about 10% of the oxygen content can produce the most OH radicals, so we can choose the working condition as multi-pollutants removal in flue gas.