Drying Strategies for Fluidized-Bed Drying of Paddy

Abstract

The main objective of this work was to determine an effective moisture diffusivity of long grain rice during fluidized-bed drying (FBD) with inlet drying temperatures ranging of 40-150°C by 10°C/step and to investigate the specific energy consumption of the FBD process. Three initial moisture contents of the local indica paddy were set at 25.0, 28.8 and 32.5% dry-basis. The experimental results of thin-layer fluidized-bed drying for the long grain rice variety were determined and statistically analyzed by non-linear regression method. The results showed that an effective diffusion coefficient was highly dependent on the drying temperature, compared to initial moisture content. Consequently, the mathematical simulation of FBD, using the developed thin-layer drying mentioned above, was evaluated and used for predicting the paddy drying system. The simulated value of energy consumption in each of the drying conditions was comparatively simulated. The simulated results showed that a FBD with low temperatures and low initial moisture content gave higher specific energy consumption than drying with high temperatures and high initial moisture contents. The total specific energy consumption increased with a decreased fraction of re-circulated outlet drying air. According to the simulation results and our previous work, the conclusion is that the long grain paddy drying with FBD technique under a high initial moisture content and drying air temperature over 100°C is the good drying condition for recommendation.