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

Abstract

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 °C and 50 °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.

Highlights

• Temperature and pressure drop measurements showed great potential for monitoring the particles;

• Pressure and temperature measurements between of constant and falling rates periods had changed significantly;

• Standard deviation measures behaved in a similar way to pressure drop;

• Power spectra became wider and showed a decrease in amplitude during the operation.

Keywords:

• Fluidization
• signal processing
• spectral analysis
• Persian clover
• arrowleaf clover

Acknowledgements

The authors thank CAPES (Coordination for the Improvement of Higher Education Personnel)/Brazil and FAPERGS (Research Support Foundation of Rio Grande do Sul State)/Brazil for the financial support. They too thank CEME-SUL/FURG (Electron Microscopy Center of South/Federal University of Rio Grande/RS/Brazil) due to scanning electron microscopy analysis and EMBRAPA Temperate Climate (Brazilian Agricultural Research Corporation)/Brazil for seeds donation.

Declaration of interest statement

The authors confirm that they have no conflicts of interest with respect to the work described in this manuscript.

Additional information

Funding

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior; Fundação de Amparo à Pesquisa do Estado do Rio Grande do Sul.