Energy Efficiency Optimization For H₂S Degradation By Dielectric Barrier Discharge ?DBD? Plasma

In recent years,the problem of odor pollution has become increasingly serious,endangering human health and living environment,and the control of odor pollution has been paid more and more attention.Dielectric barrier discharge(DBD)plasma technology has the advantages of convenient start-up,fast response,larger injection power and less occupied area.There is a matching law between the power supply parameters and the reactor parameters,which affecting the injection power and the power factor,thus affecting the degradation of odor pollutants.In this paper,H2S was used as the pollutant.The influence of the power supply parameters and the reactor geometry parameters on the power consumption,load characteristics and impedance matching of the DBD system were studied systematically,and the effect on the degradation efficiency of H2S was studied.The load characteristics and power consumption are analyzed by equivalent circuit simulation,and compared with the experimental results.Besides,the effect of catalyst loading on the discharge characteristics and degradation efficiency was studied.The main conclusions are as follows:(1)Quantitative analysis of the relationship between the active power of the DBD discharge system and the load voltage,discharge frequency,discharge area length and discharge air gap can be expressed by P = A · L ·f · Vn.The value of A does not change with the length of the discharge area,and decreases with the increase of the discharge air gap.The value of n has nothing to do with the discharge area length and the discharge gap.The experimental results of H2S degradation efficiency verify the quantification of active power,in which the discharge gap is the best value,5mm.(2)The relationship between the power factor of the discharge system and the discharge frequency and the geometrical parameters of the reactor was studied.As the discharge frequency increases,the power factor increases first and then decreases,and there is an optimal frequency point.The optimum frequency is different under different reactor geometric parameters.In the different discharge area length,the maximum power factor is nearly same.With the discharge gap increases,the maximum power factor increases.The maximum power factor is 0.583.(3)The resonant matching between the power supply parameter and the reactor parameters was studied.The change of the resonant frequency of the system is due to the change of the equivalent capacitance of the dielectric layer,and the resonant matching law exists between the discharge frequency and the equivalent capacitance of the dielectric layer.The equivalent capacitance of the dielectric layer increases with the increase of the load voltage,which is proportional to the length of the discharge area.The change of the discharge air gap has little effect on the equivalent capacitance of the dielectric layer.The best discharge frequency,in which the degradation efficiency is the best is consistent with the resonant frequency.(4)The power characteristics and load characteristics of the DBD system were analyzed by the equivalent circuit simulation.The secondary side reactance constitutes the main part of the impedance,the secondary impedance increases first and then increases with the frequency,and the minimum frequency corresponds to the resonant frequency,in which the discharge power is the largest.The leakage inductance Ls = 1.543H and the parasitic capacitance Cs = 62.7pF of the power supply are analyzed by the equivalent capacitance of the dielectric layer.The simulated amplitude-frequency characteristics and power factor are in good agreement with the experimental results.(5)The effect of catalyst filling on the discharge characteristics of DBD system and the degradation efficiency of H2S was studied.With the catalyst filling,the equivalent capacitance of the dielectric layer and the equivalent capacitance of the air gap are both increased.The resonant frequency of the system is reduced and the active power is improved.When the load voltage is 11 kV,the catalyst filling increases the active power by nearly doubling.At the same energy density,the addition of the V/Ti catalyst increases the degradation efficiency of H2S by about 20%to about 50%.With the increase of V loading,the specific surface area of the catalyst decreases,but the oxidation capacity increases.The degradation efficiency,energy efficiency and SO2 selectivity of hydrogen sulfide increase with the increase of V load.