Monitoring pulverised coal flames

A series of burner diagnostic tests using infrared (IR), microphone and acoustic emission (AE) sensors were conducted on a 150 kW pf burner rig. These experiments systematically varied the burner swirl number and the secondary airflow rate over a significant range for two different coals so that both satisfactory and 'poor' combustion conditions were obtained. The signals from the sensors were analysed by using advanced signal processing techniques to reveal a number of features which in turn were then compared with the nitrogen oxides (NO_x), carbon monoxide (CO) and oxygen (O₂) through a correlation coefficient analysis. It was concluded that these sensors can be used for the prediction of these emissions and will be particularly attractive for multiple burner installations where the pollutant emissions are often discharged through a common manifold, so that individual burner performance is often not known and cannot be optimised.