An experimental research to determine the fluidized bed regime of pepper in the fluidized bed drying process

Abstract

This is an experimental study to determine that the minimum fluidization velocity, the fluidized bed height, and the pressure loss through the grain layer depend on the thickness of grain layers and moisture content of materials. The drying materials used in this study are fresh pepper and dried pepper of which moisture content is 54.2% and 12%, respectively. All the experiments are conducted with the thickness of the pepper layer ranging from 4mm to 44mm while the wind speed ranging from 5 m/s to 11m/s. From the result of experimental analysis, it can be seen that the minimum fluidization velocity of an air stream through fresh pepper ranges from 5.2m/s to 6,5m/s. The pressure drop of air stream through the fresh pepper is 225Pa while 147Pa for dry pepper, corresponding to the grain thickness of 37mm layer. By comparing the results determined from these experiments with computational models and some available correlations, the computational models of Fedorov, Baeyens-Geldart and Leva all match the experimental data collected from the pepper material. The correlation between the calculated and experimental results has a negligible error, the tendency to increase pressure loss depends on the thickness of grain layer is also quite similar. From the experimental data results obtained by determining the pressure drop through the pepper layers which depends on the thickness of both fresh pepper and dried pepper, the linear equations of the first order are established with high credibility.