| Industrial exhaust, such as yellow phosphorus tail gas, blast furnace gas, water gas, sealed calcium carbide furnace tail gas, often contain a large number of different pollutants, including dust, H2S, PH3, COS, Hg and so on. The H2S pollutants has very low smell threshold and high toxicity. The traditional methods in the treatment of H2S waste gas often have the problems of high investment, complex operation, conversion efficiency instable and so on. What’s more, if the H2S gas contains dust, the removal process of dust and H2S must be separated, which will prolong the process, increase investment. So the technology which can purify dust and exhaust gas like H2S simultaneously has got more and more attentions. While the corona discharge is one of the most promising technology.In this article, we use the corona discharge plasma to remove the hydrogen sulfide and dust simultaneously. We use the gas distribution system to simulate the H2S gas containing dust. And the effects of electrode shape, discharge gap, initial concentration, oxygen concentration, relative humidity, residence time, ozone concentration and dust concentration on H2S conversion were investigated. And the study focuses on the ability of corona discharge plasma on the separation and transformation of H2S and dust simultaneously, as well as the interaction between the H2S and dust in the transformation process. Through XRD and XRF techniques to analyze the change of dust before and after reaction and the possible transformation ways of H2S are proposed. The main conclusions are as follows:The experiment shows that the greater electrode radius of curvature is, the worse H2S conversation is got. The best effect to convert H2S is round steel electrode, the worst is saw tooth electrode. The maximum input energy of the reactor was increased will the increasing of discharge gaps, but the conversion of H2S decreased. And the discharge gap of 20 mm at the same SIE obtained the highest H2S conversion rate. The transformation product of H2S is mainly SO2. With the increasing of SIE, the conversion of SO2 is further oxidized to SO3 and SO42-. So that the yield of SO2 decreased. With the increasing of H2S concentration, the removal efficiency of H2S decreased gradually under the same SIE. But the energy yield was increased with the increase of the inlet concentration. And at the same inlet concentration, the EY decreased gradually with the increasing of SIE. The existence of O2 has an important influence on the corona discharge and H2S conversion, its existence will be beneficial to the stability of the discharge. And the higher the concentration of O2, the lower conversion rate of H2S and the higher yield of SO2. H2S transformation depends mainly on the direct effects of electrons and free radicals, while the ozone has little effect. When relative humidity is 41%, it got the highest conversion efficiency of H2S.If keep increasing the relative humidity, the H2S conversion will decrease. The longer the residence time is, the higher the conversion rate of H2S is got. But the energy yield of H2S decreases with the increasing of residence time.The corona discharge plasma can remove the dust and H2S simultaneously. Existing of dust can not only reduce the energy consumption of H2S conversion and improve the removal efficiency, but also inhibit the yield of SO2 for it can further react with some compounds in the dust. Metal oxide of the dust will react with H2S or SO2 in the corona discharge plasma, which make the sulfur element fixed in the dust. The higher dust concentration is, the higher H2S conversion rate was got under the same SIE condition. With the existing of CO, corona discharge can remove H2S and has little influence on the CO. When the mixed gas contains COS, the H2S was conversated priority.With increasing of COS, H2S removal efficiency decreased gradually. But if enough energy was given, H2S and COS can be totally transformed. |
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