Experimental And Theoretical Study On Flue Gas Denitrification With Radical Shower Induced By DC Corona Discharge

The thesis reviewed every kind of flue-gas DeNOx technologies firstly, and introduced both the research results of removal of the NOX from flue-gas with corona discharge technologies and the research work on discharge mechanism.The experiments on removal of NOX from the flue-gas using NH3 as radical resource were carried out. The results showed that water vapor restrains the discharge process, but proper content of water vapor in flue-gas will improve the removal efficiency, the quantity of NOX that removed by unit energy from the flue-gas that contained 10% of water vapor is the highest, and double that of pulsed corona technologies. The temperature of flue-gas affected on the discharge process a little, but high temperature would reduce the removal efficiency of NOX. The flow rate of flue-gas impacted on the discharge faintly. The higher the flow rate of flue-gas is, the higher energy efficiency would be obtained. It is moderate that the flue-gas residues in the reactor for 5-7 seconds. To improve the removal efficiency by the way of lengthening residence time of flue-gas in the reactor is not economical. The removal efficiency would be reduced if the concentration of the NOX increased, the energy efficiency enhanced on the other hand. The shorter distance between the anode and the cathode would result in both lower started corona voltage and lower breakdown voltage. Long distance is beneficial to obtaining high discharge power.Removal of NOX from flue-gas by H2O+O2 radical injecting integrating with alkali solution scrubbing is carried out. The steady streamer corona occurred when the water vapor feed into the nozzle electrodes was moderate. Some of the NO will convert into NO2 in the reactor. The NO2 react with OH radicals and convert into HNO3 at the end. The rest of NO in the reactor converts into HNO3 after reacting with OH radicals. Most of the reaction production in the reactor is HNO3. The highest DeNOx efficiency is above 70%. To increase the humidity of the oxygen that feed into the nozzles will improve the DeNOx efficiency. The NO absorbed by NaOH solution was little than 30%, the percent of NO, absorbed by NaOH solution was more than 90%. The overall DeNOx efficiency approached 90% after the flue gas absorbed by NaOH solution and the Ca(OH)2 solution absorbed the NO2 well also. This indicated that to remove the NOX, which is the production of corona discharge, by wet desulfurization system is feasible.The electrostatic field of the nozzle brim was simulated with simulation-charge technique and complex transformation. The experiment project was proved to befeasible by simulation process. The solution of electrostatic field was approached and this is the foundation of the subsequent research. The critical position, which was the start position of the Monte Carlo simulation of steamer corona discharge, was solved too.The streamer corona discharge in the experiment system was simulated with Monte Carlo simulation. The simulation result showed that the electron energy distribution of different positions is different. The quantity of higher-energy electrons near the anode is much more than other positions. The space electric field is distorted because of the charges accumulation. The electric field near the anode is lower than Laplace electric field, and the electric field near the cathode is higher than Laplace electric field. The streamer corona appears as pulse because of the distorted electric field, and the discharge current appears as pulse too.The unit energy yield of every kind of radicals in the radical injecting process was computed. The dissociated probability of the N2 in the flue-gas is low, but the dissociated probabilities of O2 and H2O are high comparatively.The oxidizing efficiency of NOx in reactor was forecasted, and the computed results are accordant with the experiment results. The removal efficiency of NOx was computed in different velocity flue-gas at a constant power of 5 watt. It was founded that the removal efficiency of NOX increases with the residues ti...