Study on Co-firing Characteristics and NOx emission of Ammonia/Propane

Abstract

Reducing the use of carbon fuel is one of the important measures to achieve zero carbon emission. As a carbon-free and high-hydrogen fuel, ammonia has promising application prospects because of its high energy density and low transportation and storage cost. Due to the characteristics of high ignition temperature, low flame propagation combustion speed and high NOx concentration in the combustion process, its wide application needs further research. In this paper, the co-combustion and the NOx emission characteristics of ammonia mixed with propane are experimental investigated for pure ammonia, 5% propane and 10% propane mixtures. The effects of ammonia/propane ratio, air excess coefficient and inlet gas oxygen concentration on combustion and NOx emission characteristics are explored. The results obtained show that the highest NOx emission is formed by 10% propane ratio case, and the lowest NOx is for pure ammonia. With the increase of propane, the concentrations of NOx, NO and NO2 increase and the concentration of oxygen decreases. With the increase of air excess coefficient from 15% to 21%, NOx, NO and NO2 also increase, and the concentration of oxygen goes up. With the increase of inlet oxygen concentration from 15% to 21%, the concentrations of NOx and NO at the exit of furnace changes less for pure ammonia, and 75% increase for 5% propane; while for 10% propane, the concentration of NO first decreases rapidly from 1498ppm to 1071ppm with O2 decreasing from 15% to 18%, then increases to about 1700ppm again when the inlet O2 concentration increases from 18% to 21%.