Numerical Analysis of Repetitive Pulsed-discharge DeNO_x Process with Ammonia Injection

Due to the relatively high performance and the compactness, the pulsed-discharge deNO_x process is expected to be one of the next generation technologies to suppress air pollution. However, sufficient guide lines for the optimum operation of pulsed-discharge deNO_x process has not been presented. In this study, we have simulated numerically the process applied by several hundreds pulsed-voltages. and investigated the effects of by-products and ammonia injuction on the deNO_x performance. In a case for the no ammonia injection, both of the N_xO_y removal efficiency and the electric energy consumption to remove X_xO_ychange with increasing repetitive pulse number, because electrons produced by the discharge recombine with accumulated by-products, such as of H₃O⁺(H₂O)₂. followed by decreasing radical concentration and oxidative/reductive removal reactions. In a case for ammonia injection, the removal efficiency increases and the electricity consumption decreases with increasing the ammonia concentration, because removal reactions such as [formula omitted] and [formula omitted] become active. When ammonia is injected excessively, the deNO_x performance declines because the NH₂ radical produced by the electron collision with ammonia reacts with NO₂ to make relatively stable N₂O.