MASS AND ENERGY BALANCE ANALYSIS OF A CONTINUOUS BELT DRYER FOR A FLOATING FISH FEED

Abstract

The extruded fish feed are usually moist which cannot be stored or transported without drying. Hence, the need for effective drying of the feed extrudate is essential. A continuous belt dryer was explored for the mass and energy balance analysis of fish feed extrudate. In this study, a continuous belt dryer was evaluated for integration into an industrial fish feed production process. The dryer was evaluated for performance by introducing extruded fish feed into it via the hopper and a mass of 2 kg were collected periodically as drying took place. The process was repeated for selected drying air velocities of 0.8 m/s, 0.9 m/s, 1.0 m/s, 1.1 m/s, and 1.2 m/s, with varying drying temperature levels of 60, 70, 80, 90 and 100oC. The drying rate of the fish feed were determined to explain drying process of fish feed under varying drying conditions of drying air temperature and air velocity. The analysis reveals that increase in the drying temperature of the belt dryer from 80oC to 100oC resulted in an increase in the amount of moisture removed from the extruded fish feed over 30 minutes. The results show that the moisture diffusivity values were in the range of 3.08×10–9 – 4.01×10–9 m2/s, While the activation energy (Ea) for drying fish feed extrudates varied from 6.47 to 17.244 kJ/mol for air velocities between 0.8m/s to 1.2m/s. The increase in the temperature was directly proportional to the drying rate of the extruded feed and therefore reduced the drying time. Also, increasing air temperatures and air velocity was found to result in a higher dryer performance and vice versa