The effect of AC applied voltage phase differences on the NOx reduction from the combustion flue gases by superimposed surface and silent discharge plasma reactors

The effect of AC applied voltage phase differences on NO_x reduction from combustion flue gases by a superimposed surface and silent discharge plasma reactor is experimentally investigated. The experiments are conducted for applied voltages from 0 to 24 kV, flue rates from 0.5 to 2 l/min, ammonia mixture concentration from 0.7 to 1.2 stoichiometry, and applied phase differences from 0 to 180 degrees, where two 60 Hz AC power supplies are used. The results show that: (1) NO_x reduction rate increases with increasing discharge power, gas flow rate and ammonia stoichiometry for in-phase operations; (2) NO _x reduction rate for out-of-phase operations is much higher compared with in-phase operations. However, NO_x reduction rate has an optimum condition on ammonia stoichiometry, discharge power and gas flow rate; (3) energy efficiency of NO_x reduction increases with increasing ammonia mixture and gas flow rate, and decreases with increasing discharge power; and (4) energy efficiency of NO_x reduction under out-of-phase operations is much larger compared with in-phase operations