OPTIMIZATION OF A CLAY-SLATE FLUIDIZED BED DRYER FOR PRODUCTION OF FISH FEED

Abstract

For feed producers who suffer from high intolerance to production costs, the only way to cope with the condition is to avoid devices that drive up costs. Extruded feed processed from a clay-slate dryer through a fluidized bed could be used to make fish feed. The aim of the study was optimise the process conditions on the clay-slate fluidized bed dryer operating at a commercial production of fish feed using the response surface methodology. The fish feed composition were processed at bed height (50-200 mm), drying air temperature (60–120°C), airflow velocity (0.66-0.70 m/s), drying time (10–90 min) and extrudates size (4–8 mm). Product quality parameters such as moisture ratio and dryer efficiency were determined and analyzed. Second-order polynomial equations, containing all the process variables, were used to measured process. Moisture ratio was influenced mostly by linear relationship temperature and drying time. The temperature and the quadratic temperature conditions significantly affected the efficiency of the dryer. For the fluidized bed drying of extruded fish feed, optimal conditions were set for the bed height of 185.76 mm, a temperature of 97.2°C, an air flow rate of 0.67, a drying time of 65.36 min and an extrudate size of 7.40 mm recommended. At these conditions the moisture ratio and efficiency were 0.86 and 74.39, respectively. The influence of the various components of the fluidized bed dryer on the drying rate must be better understood so that control systems can be developed to take full advantage of this technology.

Keywords

• fluidized bed drying
• fish feed
• extruder
• process optimization
• response surface
• polynomial equations