Research Of Mercury Waste Emission Treatment By Non-Thermal Plasma Technology

We designed dc high voltage narrow pulse plasma reaction device including plasma power supply and reactor ourselves. We made researches to deal with mercury flue gas by the NTP technology through changing the power supply parameters such as pulse frequency and discharge voltage, contents of O2 and H2 O, HCl addition amount and concentration of NO and SO2. Experiments show that the higher the voltage, the better treatment effect. When the discharge voltage is 12 k V and the pulse frequency is600-800 PPS, the removal efficiency is the best. With the increase of initial concentration of Hg0, the oxidation efficiency increase after decreases first. When initial concentration of Hg0 is 125.3 ug/m3, It's the best. Add O2 can increase the concentration of O3 and other active oxides, thus promotes the oxidation of elemental mercury. Addition of NO,SO2 can inhibit the oxidation of mercury, and NO inhibits significantly, which mainly due to NO can react with O3. The addition of HCl will promote the oxidation of mercury, but it also can make the initial mercury concentration change. Low content of H2 O will promote mercury oxidation, while high content of H2 O can inhibit mercury oxidation.The addition of water vapor will also affect the mercury initial density. When the Power supply is 12 k V/600-800 PPS and the flue gas composition is 10% O2/3%H2O/50 ppm HCl, the elemental mercury oxidation rate can rise up to 97.95%. Then adding 100 ppm NO, the mercury oxidation rate suddenly dropped down to 20%. According to the above theory research results, we made a field experiment about dealing with the waste mercury gas produced by thermal desorption using the NTP technology. Results show that the pyrolytic temperature mainly affects the valence state distribution of mercury in flue gas,and the waste mercury catalyst content mainly affects the density of mercury. By changing the species and amount of additives, we achieved the Hg0 oxidation rate of 55%and the total mercury removal rate of 42% respectively. In this paper, our study proved that non-thermal plasma technology is the potential of technology to remove off the industrial mercury gas.