A differential thermal probe for anticipation of defluidization of caking coals

Abstract

In batch fluidized beds of caking coals, differential thermocouple (DT) probes were shown to detect incipient defluidization appreciably sooner than pressure probes and with more definite response. Operating factors affecting the temperature of incipient defluidization and the time between initial and total defluidization (the degree of anticipation) are discussed. The resulting relationships can be qualitatively explained by fluidization and heat transfer theories. Fluidized beds incorporating DT probes would appear to have application to other materials and to characterization and control of fluidized bed operation.