An experimental investigation into ammonia dissociation, oxidation and NO emission in a vertical flow reactor

Abstract

Ammonia (NH3) dissociation, oxidation, and associated nitric oxide (NO) emission in a vertical cylindrical quartz reactor is investigated to establish the effect of temperature (1000 K–1400 K), initial NH3 concentration (2%, 4%, 6%, 8%, 10%) and flowrate (250 mL/min, 500 mL/min, 750 mL/min). Ammonia oxidation experiments also examine the effect of equivalence ratio (ɸ = 0.8, 0.9, 1.0, 1.1). The NH3 and O2 conversions, N2 yield, and NO emission are determined by analysing the reactor effluent compositions. Ammonia dissociation of <6% is observed for all conditions tested. Ammonia oxidation is initiated at ∼1100 K, with majority of NH3 conversion occurring at 1200 K–1300 K before completion at ∼1325 K. NO emission becomes significant at temperatures >1300 K for ɸ ≤ 1.0 and increases with decreasing equivalence ratio. Under fuel-lean conditions, increasing initial NH3 concentration increases NO emission. Fuel-rich conditions return negligible NO, attributed to the reductive effect of excessive NH3.