Experimental investigation of the combustion instability behaviors and NOx emissions in an ammonia/methane fueled low eddy premixed burner

In this study, experimental analyzes were carried out to examine the combustion instability properties of methane-ammonia mixed fuels for a low eddy and premix burner. The aim of this study is to determine the effect of ammonia addition on combustion instability with different compelling acoustic frequencies, dynamic pressure amplitude, and light emission intensity. In addition, the effects of ammonia addition to methane fuel gas on temperature and emissions were also investigated. Pure methane and three different methane-ammonia mixtures as fuel at 0.7 equivalents and with three different acoustics have been used for analysis. The burner power was determined as 5 kW and the excitation frequencies of the combustion chamber were determined as 95, 160, and 300 Hz. As the ammonia addition increased, there was an increase in the flame instability values up to 30% NH3, especially at the 95 Hz frequency, where the highest distortion effect occurred. It was observed that there was no significant change in the combustion performance with the addition of ammonia to methane fuel. The predicted NOX emission levels were found to increase significantly due to nitrogen bound to ammonia. However, it is seen that the NOx emission levels in the exhaust measurements are not high.