Monitoring of the fluidized bed particle drying process by temperature and pressure drop measurements

This work aimed to monitor the temperature and the pressure drop behaviors in bed during the drying of Persian clover and arrowleaf clover seeds in a fluidized bed. The inlet air temperatures were of 40 degrees C and 50 degrees C, with a fixed bed height (H-l:D-l ratio of 1:1) and fluidization velocity of 2.7 times the minimum. For the temperature and the pressure drop profiles in bed and the standard deviation of pressure drop, all changed significantly during the process in function to solids moisture content, mainly on the transition of the constant rate period to the falling rate period, due to change of the mass transfer mechanisms. In addition, an analysis of pressure measurements in the frequency domain was performed, using the Fast Fourier Transform, and power spectra of distinct characteristics for the two drying periods was obtained, showing that this technique can be a potential alternative for operation drying monitoring.