Time dependence of NOx removal rate by a corona radical shower system

In this paper, the effects of flow rate of treatment gas and additional gas on the corona current-voltage characteristics and NO_x removal characteristics, and the operational time dependence of the corona characteristics and NO_x removal characteristics are investigated experimentally in a corona radical shower system. The corona current-voltage characteristics have two modes which have a significant influence on NO_x removal characteristics. The threshold value of the gas flow rate ratio of treatment gas to additional gas is about 8. The hysteresis of corona current-voltage characteristics is observed in this system. For longer operational time, corona current and NO_x removal rate significantly changes with time. When the operation of the apparatus starts at relatively low applied voltage, the corona current under constant applied voltage increases with time. It takes a maximum value at an operational time and then decreasing with time, finally settles down to a constant value. At this condition, high NO_x removal rate NO_x removal efficiency can be achieved