Temperature profiling of pulverised coal flames using multi-colour pyrometric and digital imaging techniques

This paper presents an imaging based multi-colour pyrometric system for the monitoring of temperature and its distribution in a coal-fired flame. A novel optical splitting/filtering device is designed and used to split the light of flame into three beams at three selected wavelengths as required in the multi-colour principle. A high-resolution CCD camera is employed to collect the three beams of the light of flame. The three resulting images provide the basis for the determination of temperature and its distribution in the flame field. The system is evaluated on a 0.5-MW_th coal-fired combustion test facility under various combustion conditions. Results obtained demonstrate that the system is capable of measuring the temperature and its distribution concurrently in the flame field. Quantitative relationships between the measured results and the main combustion process data are also discussed.