Pyrometric temperature and size measurements of burning coal particles in a fluidized bed combustion reactor

The article reports on the application of fiber-optic two-color optical pyrometry to the measurement of temperature and size of combusting coal particles in an atmospheric fluidized bed combustion reactor. The utility of the measuring technique is that it makes possible nonintrusive in situ measurement of the dependence between the temperature and size of combusting fuel particles. The method allows the temperatures of the fluidized bed and individual fuel particles to be determined wherever these deviate from the bed temperature. Besides giving these temperatures, this method also allows for the statistical determination of the particle size distribution within the population of observed particles. The effects of bed temperature (1130-1200 K) and oxygen concentration (5-8 vol%) on the temperature of combusting Westerholt high volatile bituminous coal particles were studied in a laboratory-scale bubbling fluidized bed combustor. The average particle temperature exceeded the bed temperature by about 100-200 K,while the maximum particle temperatures were nearly 600 K above the bed temperature. The interrelation between the size (< 1.2 mm) and temperature of burning coal particles is presented. (C) 1999 by The Combustion Institute.