The Optimization On Structures Of Dielectric Barrier Discharge (DBD) Reactor For Odor Treatment

Odor pollution is one of the world’s seven major environmental hazards. In order to find out more efficient treatment technology, hydrogen sulfide (H2S) was chosen as aim pollutant to be destructed. A series of experiments were performed in three dielectric barrier discharge (DBD) reactor to remove H2S from a gaseous influent at room temperature and atmospheric pressure.Removal of gaseous H2S was studied with low-temperature plasma induced by tubular dielectric barrier discharge reactor. The effects of applied voltage, original concentration, gas flow rate as well as the reactor configuration on H2S removal efficiency (ηH2s) and energy yield (Ey) were investigated. The results are as follows: Higher applied voltage contributed to higher ηH2s.With the applied voltage was13.2kV, ηH2s and Ey could up to69%and3081mg/kWh under the experimental conditions of gas flow rate of8.0m/s, inlet H2S concentration of40mg/m3and5layers of calandria quartz tubes, respectively. The gas residence time would decrease with the increasing gas flow rate and resulted in lower H2S removal efficiency. Under the conditions of applied voltage of13.2kV, inlet H2S concentration of40mg/m3, gas flow rate of6.0m/s and5layers of calandria quartz tubes, ηH2S and Ey could be76%and2541mg/kWh. Lower initial concentration contributed to higher ηH2s.More calandria quartz tubes had great effects on ηH2s and Ey.A combined plasma photolysis (CPP) reactor that utilized the dielectric barrier discharge (DBD) plasma and DBD-driven KrI*excimer ultraviolet emission was applied to the decomposition of H2S gas. The effects of applied voltage, input current, gas flow velocity, original concentration as well as the ratio of Kr/I2mixture on H2S removal efficiency were investigated. A comparison was made between the removal efficiency of DBD and CPP at same conditions. In addition, the reaction mechanism was also discussed in this paper. The results are as follows:Higher applied voltage contributed to higher ηH2s.With the applied voltage increasing from6.6kV to15.0kV, ηH2s increased quickly from25%to90%in CPP-A under the experimental conditions of input current of2.4A, gas flow velocity of2.0m/s and inlet H2S concentration of40.6mg/m3, respectively. Higher input current could lead to an increase of ηH2s.With input current changing from1.6A to2.8A, ηH2S increased quickly from4%to37%in CPP-B under the experiment conditions of applied voltage of13.2kV, gas flow velocity of3.5m/s and gas inlet concentration of100.7mg/m3, which led to an increase by33%. Lower initial concentration contributed to higher ηH2s.But, a proper higher inlet concentration of H2S favored the better use of the energy and higher H2S removal efficiency. The gas residence time decreased with the increasing gas flow velocity and resulted in lower H2S removal efficiency. Under the conditions of applied voltage of15kV, input current of2.8A and inlet H2S concentration of40.6mg/m3, ηH2s decreased from90%at2.0m/s to36%at3.5m/s. Higher Kr pressure was beneficial for the decomposition of H2S. Under the same experimental conditions, CPP reactor would lead to an increase of14%in ηH2s and an increase of160mg/kWh in Ey comparing to single DBD.In addition, the Ey and economic rationality of tubular DBD reactor, single DBD and CPP reactor were investigated.