Study On The Simulation Of Flue Gas Desulfurization And Denitrification By A Strong Ionization Discharge With Ozone

Sulfur dioxide(SO2) and nitrogen oxide(NOX) from flue gas are the main substances in air pollution. They can set off a series of chemical reactions in the atmosphere to form acid rain,which brings about catastrophic environmental pollution problems for human beings and becomes one of the hot social problems. The new " emission standard of air pollutants for thermal power plants " sets more stringent emission standards, which leads SO2 and NOXemissions of many enterprises(such as thermal power plants) can not follow the new standard. In order to make gas emissions meet the new standards, research in theory and technology must be intensified, and the new breakthroughs can be achieved.On the basis of the physical and chemical properties of strong ionization discharge desulfurization and denitrification and the theory of gas discharge, this paper discussed the mechanism of the non-equilibrium plasma produced by the strong ionization discharge with ozone,and established a chemical kinetic model for the desulfurization and denitrification by the strong ionization discharge with ozone. The numerical calculation of the model was calculated by MATLAB The variation of the main active particles in the process of strong ionization discharge with ozone and the influence of different gas concentration ratio on the concentration of active particles were analyzed.All above provided theoretical basis for experimental analysis.Experiments have researched the effects of water content, oxygen content, initial concentration,adding voltage and discharge frequency on the desulfurization and denitrification efficiency by the strong ionization discharge with ozone. The suitable conditions for desulfurization and denitrification were obtained. At last, the composition of the by-product of desulfurization and denitrification was analyzed. The mechanism of the ozone synergy strong ionization discharge desulfurization and denitrification discussed before was confirmed. The results are as follows:(1)During the process of the reaction of strong ionization discharge with ozone, O free radical produced had the highest concentration. The concentration of oxygen active particles was much higher than that of reducing particles. Desulfurization and denitrification process was mainly oxidation.And the above process produced H2SO4、HNO3 at last. The increase of oxygen content was beneficial to the increase of O3 concentration in the equilibrium of the reaction system, and was conducive to the formation of a large number of O and ·OH.(2)When the total flow rate was 4 L/min, the H2 O concentration was 2%, the O2 concentration was more than 25%, the O3 concentration was 186 ppm, the initial concentration of SO2 was 250 ppm, the flue gas temperature was 30 ℃, the discharge frequency was 5.15 kHz, and the discharge voltage was 3.2 kV, the desulfurization efficiency was more than 80%.Oxygen content, water content, applied voltage and SO2 initial concentration were the main factors of the desulfurization efficiency, and the discharge frequency had little effect on the desulfurization efficiency. The desulfurization efficiency increased with the increase of oxygen content, water content, the applied voltage.Theoptimal values of the above factors were 20%,2%, 3.2kV. With the increase of the initial concentration of SO2, the desulfurization efficiency decreased, and the SO2 removal tend to be a maximum.(3)When the total flow rate was 4 L/min, the H2 O concentration was 2.2%, the O2 concentration was more than 20%, the O3 concentration was 186 ppm, the initial concentration of NO was 300 ppm, the flue gas temperature was 30 ℃, the discharge frequency was 5.15 kHz, and the discharge voltage was 3.2kV, the denitrification efficiency was more than 90%.Oxygen content, water content, applied voltage and NO initial concentration were the main factors of the denitrification efficiency, and the discharge frequency had littlest effect on the denitrification efficiency. The efficiency of denitrification increased with the increase of water content, the optimal value of which was 2.2%. With the increased of oxygen content and applied voltage, the denitrification efficiency increased first and then decreased. The optimal values were25%, 2.4 kV. With the increase of the initial concentration of NO, the denitrification efficiency decreased, and the NO removal would tend to be a maximum.(4)The by-products of desulfurization were H2SO4 and HNO3. The by-product of denitrification was HNO3.