Treatment Of Malodorous Gas Containing Sulfur Compounds By Coupling Non-Thermal Plasma And Ozone Catalytic Oxidation

Th emission of sulfide malodorous gases is widespread in industrial production,with high irritation and toxicity.They can harm human's health and pollute the environment.Recently,the coulping process of Non-thermal Plasma(NTP)and ozone catalytic oxidation has been applied to degrade sulfide malodorous gases.Ozone,the by-product of NTP,can be used as oxidant in catalytic oxidation process to degrade the malodorous gases;as a result,the malodorous gases and ozone can be removed by the coupling process at the same time.However,most studies put emphasis on the characteristics and mechanism of NTP or catalytic oxidation,few studies investigated the coupling efficiency and degradation of binary components of malodorous gases.In this study,the degradation of hydrogen sulfide and dimethyl disulfide(DMDS)by the coupling process of NTP and ozone catalytic oxidation was studied,including the relationship between operation parameters and coupling efficiency,and the degradation properties of binary sulfide malodorous gases.Following is the main contents and conclusions:1.For the NTP process,the affect of input voltage,temperature,humidity,inlet concentration and energy density(SIE)on the NTP reactor parameters and malodorous gases degradation were studied.The results showed that the number of rags,the peak voltage,the gradient of rising edge and ozone yield of the NTP reactor increased with increase of the input voltage.The increase of humidity and the decrease of temperature decreased the ozone yield significantly,but showed no obvious affects on the discharge properties of NTP reactor.The removal efficiency of 198.2 ppm of hydrogen sulfide could reach 98.6%at the SIE of 45.6J/L,while the removal efficiency of 57.4ppm of DMDS could reach 92.3%at the SIE of 64.8J/L and the inlet concentration of.In addition,the degradation efficiency of hydrogen sulfide had a positive correlation with SIE and a negative correlation with inlet concentration;the fitted equation was:?=-0.198Cin+1.589SIE+69.656.2.For the coupling process of NTP and catalytic oxidation,the affect of particle size,residence time in catalyst bed,temperature and humidity on the degradation of hydrogen sulfide and DMDS were studied.The optimum parameters were following:the particle size of 20-40 mesh,the residence time in catalyst bed of 0.54s,the temperature of 303K,the relative humidity of 0.The main degradation product of both hydrogen sulfide and DMDS by the coupling process was SO2.At the SIE of 22.4J/L,for hydrogen sulfide,81.9%of sulfide were converted into SO2,while 48.3%for DMDS.There were some sulfide depositions in the surface of catalyst,which blocked the pore of the catalyst.3.Ozone demand factor(Df)was the key parameter of coupling process,which determined the outlet concentration of malodorous gases and ozone.It depended on the two key parameters in NTP process:SIE and inlet concentration(Cin).For hydrogen sulfide,Ln(Df)had a linear positive correlation with SIE/Cin;when SIE/Cin was controlled at 0.22-0.25,the outlet concentration of hydrogen sulfide and ozone could be under 5.0ppm and 3ppm,respectively.For DMDS,Df had a linear positive correlation with SIE/Cin;when SIE/Cin was controlled at 0.72.the outlet concentration of hydrogen sulfide and ozone could be under 10.0ppm and 5ppm,respectively.4.The degradation characteristics of binary sulfide malodorous gases(hydrogen sulfide+DMDS)by the coupling process were studied.When xxx-57.4ppm of DMDS)was mixed into 343.1ppm of hydrogen sulfide,the degradation efficiency of hydrogen sulfide in NTP showed no obvious change compared to single component hydrogen sulfide.However,the degradation efficiency of hydrogen sulfide in catalytic oxidation process decreased with increase of the concentration of DMDS.On the contrary,when 343.1ppm of hydrogen sulfide was mixed into 57.4ppm of DMDS,the degradation efficiency of DMDS was decreased in both NTP and catalytic oxidation process.For the binary sulfide malodorous gases of 343.1ppm of hydrogen sulfide and 57.4ppm of DMDS,Ln(Df)had a linear positive correlation with SIE/?(Cin)(Ln(Df)=24.039 SIE/?(Cin)-2.8342,R2=0.968).When SIE/E(Cin)was controlled at 0.28,Ln(Df)was at 4,and the outlet concentration of hydrogen sulfide,DMDS and ozone could be under 5.0ppm,3.0ppm,and 5ppm,respectively.