Basic Research On Ozone Production From Dielectric Barrier Discharge

As China's energy consumption is increasing,the requirements for pollutant removal technology are becoming higher and higher.With the emphasis on eco-environmental protection,China has successively issued a series of regulations to impose strict regulations on pollutant emissions from pollutants,industrial kilns,coal-fired boilers and thermal power plants.Various pollutant discharge standards stipulate emission standards for particulate matter,inorganic substances such as SO₂,NO_x,and HCl,heavy metals such as mercury and its compounds,and organic substances such as benzene,toluene,xylene,phenols,formaldehyde,acetaldehyde,methanol,and hydrocarbons.In the face of increasingly strict emission standards,the existing denitration methods have the disadvantages of single function,large floor space and high cost.The synergistic removal of multiple pollutants is an inevitable development trend.The synergistic removal technology of flue gas multi-contaminants based on active molecular ozone oxidation has the characteristics of small footprint,convenient transformation,rapid reaction and good pollutant removal effect,and has been widely used.However,the current efficiency of commercial ozone generators is generally much lower than the theoretical value of thermochemistry.In this paper,the key issue of excessive ozone energy consumption in the active molecular ozone denitrification process is studied in depth.For the dielectric barrier discharge process,based on the previous research,N?²P?,O?¹S?and each excited state?single state:N₂?a¹??,N₂?W¹??;triplet state:N₂?B³??,N₂?C³??,N₂?W³??,N₂?B?³??,N₂?E³???,re-establishing the air discharge reaction mechanism of more than 650 reactions.The results show that the kinetics of O?³P?,an important precursor of ozone,changes.In the air source,the life of O₂?b?is shortened.CoMPared with the oxygen source,the ozone concentration reaches a steady state for a little slower time;single channel The kinetic model was established as a basis for global ozone generation simulation,prediction of ozone concentration and ozone yield.For the pulsed dielectric barrier discharge ozone generation,based on different pulse excitation states,the peaks of the pulse power supply under the four power supply polarities?positive pulse,negative pulse,positive and negative pulse,negative positive pulse?The effect of voltage changes on ozone generation.The results show that the bipolar pulse discharge breakdown voltage threshold is low,the unipolar ozone yield in the oxygen source is higher than the bipolar ozone yield;in the air source,the pulse air source ozone yield:positive pulse>positive and negative pulse>Negative positive pulse>negative pulse.The air source micro-hollow dielectric barrier discharge is higher than the ordinary VDBD electron density,and the ozone yield reaches 90 g/kWh or more at low SIE?<10 J/L?.The effect of pressure change on the occurrence of dielectric barrier discharge ozone is mainly studied.The effect of absolute gas pressure?0.1 MPa-0.2 MPa?on large-scale ozone synthesis in a multi-channel parallel VDBD reactor with narrow gap is studied.The discharge characteristics indicate that the plasma is in a non-equilibrium mode,and the ozone concentration increases linearly as the SIE increases in the low power density region.In the high SIE region,the ozone concentration increases slowly as the SIE increases,which is due to the thermal effect highlighting the ozone.Decomposes and reduces the formation of ozone.At the same time,due to the presence of NO and NO₂,the oxidation reaction of ozone with it further reduces ozone.The concentration of ozone in the air discharge decreases more rapidly as the SIE increases;in the oxygen source,an increase in gas pressure will result in an increase in ozone production in the high SIE region.As for the air source,the optimum gas pressure for ozone production in the high SIE region is 0.14 MPa;the typical nitrogen oxides detected in the experiment include NO₂ and N₂O,and their concentrations decrease with increasing gas pressure.For the effect of small amount of N₂ addition on ozone generation,under the input conditions of different energy density,the optimal nitrogen addition range of pulse medium barrier discharge ozone generation efficiency is between 0.3%and 2%;corresponding to different concentrations of ozone addition The peak current increases linearly with the applied voltage,and the power also tends to increase linearly with the increase of the voltage peak;if the air source is to be used to replace the oxygen source,the ozone production yield is required to reach 105 g/kWh.