NO reduction by a pulsed ammonia radical injection using one-cycle sinusoidal power source

NO in N/sub 2/ gas was removed by injecting ammonia radicals, which were externally generated by flowing the NH/sub 3/ gas diluted with Ar gas through dielectric barrier discharge with a one-cycle sinusoidal-wave power source. The generated ammonia radicals were introduced in a reaction chamber and mixed with NO gas, which was diluted with N/sub 2/. The discharge was intermittently formed between coaxial cylindrical electrodes with a space of 1.5 mm at an applied peak-to-peak voltage of 3-25 kV. A stepwise increase in NO reduction rate occurs at the critical temperature, which increases with increasing the NO and NH/sub 3/ concentrations. The NO gas contained 2-5.6 % O/sub 2/, and the effect of O/sub 2/ on De-NOx was also discussed. An appropriate concentration of O/sub 2/ gas promoted the De-NO/sub x/, but excess O/sub 2/ hindered De-NOx by newly generating NO. There are optimum conditions for NOx reduction and for its energy efficiency in the NH/sub 3/ concentration, the NH/sub 3/ flow rate, the repetition rate, and the applied voltage. Under a set of the optimum values of these conditions, the maximum value of the energy efficiency, 140 g/kWh, was obtained at a NO concentration of 908 ppm.