Experimental Research On Influencing Factors For Denitration By Dielectric Barrier Discharge

Using non-thermal plasma to remove gaseous nitrogen-containing from flue gas gradually has become the research hotspot in recent decades. And it is also considered to be a flue gas purification technology being the most environmental friendly, most promising and having the best development prospect in market. The writer designed a coaxial cylindrical dielectric barrier discharge reactor in this thesis to carry out the experiments NO removal from simulated flue gas in a small experimental system. The main purpose was to explore the influence of electrode material of the reactor, electrode surface structure, electrode access way, the discharge space gap size and the initial temperature of reaction gas on discharge characteristics, the gas discharge power and NO removal rate. Through the experiments we know that:The material of center electrode has influence on the gas starting discharge voltage. A smaller work function of metal electrode could decrease the value of discharge voltage to5.84kV and it is good for NO removal. A center electrode with a threaded surface has a more intense discharge than the smooth surface of center electrode. It could decrease the initial discharge voltage value from5.36kV to3.84kV and increase NO removal rate from74.3%to84.2%. Reducing the gas gap of the discharge space could make the gas breakdown much more easily and increase the rate of NO removal. When the gas gap reduced from8mm to6mm, the gas breakdown voltage was reduced form6.98kV to6.27kV and the NO removal rate was increased from56.8%to73.2%. Because the electric field strength is the maximum near the center electrode of coaxial circular tube-type dielectric barrier discharge, the Townsend of third ionization coefficient γ is improved and the gas breakdown voltage Vm is reduced when make the center electrode as cathode, but it has no effect on the NO removal rate. Different materials of the barrier medium have different dielectric constant, so the surface of the medium discharge voltage is varied. The barrier medium with larger dielectric constant causes more obvious electric field distortion. And it is helpful to reduce the gas breakdown voltage and to obtain higher NO removal rate. Improving the inlet temperature of the simulated flue gas is beneficial for increasing the gas discharge power and energy utilization, thus obtaining a higher rate of NO removal under lower input energy density. Through the experimental analysis and discussion we got some helpful conclusions to improve the NO removal rate and reduce the energy consumption, which is of certain guiding significance for promoting the practical application of the dielectric barrier discharge.