Green heat pump drying technology - Comparison of drying modes based on kinetics and product characterization

Abstract

The hypothesis was to study and detect if there is any difference in moisture removal kinetics and drying characteristics by operating in single and combined drying modes. In addition, based on the data from the experiments create a model describing the drying curve, in the temperature range from 25°C to 45°C. The drying modes studied were stationary, fluidizing bed and their effect when combined with mechanical vibration all at 35°C and a bed height of 15 cm. The fluidized experiments did remove moisture at a faster rate when the limiting factor was what the drying air could evaporate and transport away compared to the static experiments. When internal moisture transfer become the limiting factor, the effect of fluidization disappeared. The addition of mechanical vibration of green peas at low frequency and low amplitude does not give a notable effect for the drying rate at 35⁰C and bed height of 15 cm. The fluidization characteristics concurred very well with already known research done by Geldart. A model was created describing the drying curves for stationary and fully fluidized beds with and the model concurred very well with the experiments during the constant and falling rate periods in the temperature range from 25°C to 45°C.