Rate Measurements in a Laboratory-Scale Pulverized Coal Combustor

Abstract

An atmospheric combustor has been developed to investigate the details of pulverized coal combustion. Gas and char samples were obtained from the combustor with water-quench probes. An argon tracer was used to determine the extent of gas mixing while the extent of particle dispersion and the extent of particle reaction were determined from measured char quantity and composition. Secondary air velocity and injection angle and initial coal size were varied in 28 tests. Secondary velocity had a significant impact on gas mixing rate while particle dispersion was not influenced significantly by changes in test variables. Rates of the several processes which influence pulverized coal combustion were determined. Gas mixing, coal particle heat-up, particle dispersion and coal particle reaction times were all of comparable magnitude and were all reduced by use of smaller coal particles. Measured profiles for mixture fraction, gaseous species, particle flux and coal burnout percentage provide data for combustor model evaluation.