Reduction of NO/sub x/ from combustion flue gases by superimposed barrier discharge plasma reactors

NO/sub x/ reduction from combustion flue gases by superimposed barrier discharge plasma reactors is experimentally investigated. The experiments are conducted for applied voltages from 0 to 28 kV, flue gas rates from 0.5 to 2 L/min, ammonia mixture concentrations from 0.7 to 2.65 stoichiometry, and applied voltage phase differences from 0/spl deg/ to 180/spl deg/, where two 60-Hz AC power supplies are used. The results show the following: (1) NO/sub x/ reduction rate decreases with increasing discharge power for surface discharge operations, however, NO/sub x/ reduction rate increases with increasing discharge power for silent and superimposing discharge operating modes; (2) NO/sub x/ reduction rate increases with increasing discharge power, gas flow rate and ammonia stoichiometry under in-phase operations; (3) NO/sub x/ reduction rate for out-of-phase operations is much higher compared with in-phase operations, however, NO/sub x/ reduction rate has an optimum condition on ammonia stoichiometry, discharge power, and gas flow rate; and (4) energy efficiency of NO/sub x/ reduction increases with increasing ammonia mixture and gas flow rate and decreases with increasing discharge power.