Controllable No Emission and High Flame Performance of Ammonia Combustion Assisted by Non-Equilibrium Plasma

Owing to the problems of high NO x emission and low combustion performance of ammonia fuel, exploring new methods of enhancing ammonia combustion performance without blending with other hydrocarbon fuels becomes attractive. In this paper, combining gliding arc plasma (GAP) reactor with a swirl burner is developed to enhance the combustion performance and reduce the NO emission simultaneously. The effects of gas discharge medium, equivalence ratio (φ) and gas flow rate on the flame stability, flame speed, and NO emission were investigated. Experimental results show that with air GAP and the ammonia injected from the swirl ring of the burner, the optical emission spectrum of ammonia flame was dominated by the atom spectrum of O*, H β , and molecular spectrum of NH* and OH* component, which significantly promotes the ammonia combustion performance including the combustion limit and flame speed. In addition, the optimal NO emission can be reduced to about 100 ppm even though the equivalence ratio φ is in lean flame, and near zero at an appropriate equivalence ratio. With ammonia GAP and the air injected from the swirl ring of swirl burner, on-line hydrogen from ammonia decomposition was produced by ammonia GAP, and the NO emission was always less than 100 ppm with various equivalence ratios φ