The measurement of particle temperature in a fluidized bed dryer

A probe for particle temperature measurements in fluidized bed dryers is described in this work. The probe, consisting of a thermistor placed inside a turning cup, was tested in a pilot scale dryer, where particle temperatures were monitored during batch drying tests. The measurements were validated by comparison with readings made in collapsed beds. Temperature readings were given a physical interpretation, as surface particle temperature, or average particle temperature, depending on the drying regime. The dynamic response of the probe was also analyzed. As an application, it is shown how particle temperatures, along with local wet bulb and dry bulb air temperatures, can be used to monitor and control the drying process. The simplicity of construction, installation and associated method makes the probe attractive for both research and industrial purposes.