| The traditional air aeration method in limestone-lime wet flue gas desulfurization (WFGD) technique has problems of high energy consumption of fan, low efficiency of calcium sulfite oxidation and poor crystallization of desulfurization gypsum, ozone is selected in the process because of its strong oxidizing ability. However, due to complex ozone generator equipment, high loss of ozone and unsteady plasma device at high-speed of airflow, a set of pore type surface dielectric barrier discharge reactor was designed. The electrode structure and gas parameters were optimized to improve ozone output. In addition, the loss in transmission of ozone was studied. An oxidation experiment of calcium sulfite was conducted on our new reactor and the effects of the electric, gas and slurry were also investigated. The detailed work and results are shown as follows:(1) A pore type surface discharge reactor was designed, the discharge power and effect of ozone generation were compared to that of coil type discharge and coaxial cylinder type discharge. The experimental results showed that pore type surface discharge reactor was more beneficial in ozone generation. When the pore diameter was 6 mm and pore spacing was 3 mm under this experimental condition, ozone concentrations and generating efficiency achieved optimally; Ozone production efficiency decreased with the increase of gas temperature. When the temperature exceeded 90?, ozone generation efficiency reduced from the initial (23?) 40.11 ?g/J to 20.80 ?g/J; Ozone concentration and productivity gradually reduced with the increase of gas relative humidity. When gas relative humidity was close to 100%, ozone generation efficiency decreased from the initial (0%) 40.12?g/J to 20.31?g/J.(2) Ozone transmission loss was studied by researching transmission distance, initial concentration, gas flow rate, gas relative humidity and gas temperature. The experimental results showed that the increase of transmission distance, gas relative humidity and gas temperature made ozone producing more loss during transmission process. The decay rate of ozone was 9%when the transmission distance was 20m; It increased from 9% to 40% when the gas relative humidity increased from 0% to 100%; Ozone decayed much more obviously when gas temperature was higher than 75?; The increase of gas flow rate could reduce ozone loss, the decay rate of ozone was only 4% when transmission speed was 20 m/s; The decay rate of ozone remained around at 15% when ozone concentration ranged from 62.86 to 124.60 ?g/L under this experimental condition.(3) We applied pore type surface discharge reactor on calcium sulfite oxidation, studied the influence of electric, gas and slurry on the oxidation of calcium sulfite. The experimental results showed that the pore type surface discharge had more advantages on oxidation of calcium sulfite when comparing to coil surface discharge. After 60 minutes, the oxidation rate of calcium sulfite reached 92.4% and 85.68%, respectively. The oxidation rate of calcium sulfite increased with the increasing flow of gas, while it decreased with the increasing concentration and height of slurry. The higher temperature or the lower pH of slurry could increase oxidation rate of calcium sulfite in a certain range. When the slurry temperature exceeded 50"C or the pH was below 4, the desulfurization efficiency would decrease for the decomposing of calcium sulfite. |
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