Optimum conditions for NO reduction using intermittent dielectric barrier discharge at atmospheric pressure

NO in N2 gas was removed by injecting ammonia radicals, which were externally generated by flowing NH3 gas diluted with Ar gas through a dielectric barrier discharge (DBD) with a one-cycle sinusoidal-wave power source. The discharge was intermittently formed between coaxial cylindrical electrodes at an applied peak-to-peak voltage of 2–15 kV. The generated radicals were introduced in a reaction chamber and reacted with NO. In order to find optimum parameters for NO reduction and energy efficiency, the reaction temperature in the mixing zone, the voltage applied to the gap of the electrodes for DBD generation and its repetition rate, the NO gas concentration, and the ammonia concentration and flow rate were varied. A maximum energy efficiency of 140 g/kWh at a NO reduction of over 99% is obtained at a voltage slightly higher than the discharge firing voltage and a repetition rate of 5 kHz, which corresponds to a duty cycle of 5%. Thus it is found that the use of the intermittent power source is an advantage for obtaining a high energy efficiency of NO reduction.