635 / 2019-01-25 16:54:35

Investigation of drying peppercorns characteristics in a fluidized bed fluidized bed dryer with baffle turbulators

Fluidized-bed, turbulator drying, turbulence flow, drying rate peppercorn

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Peppercorn is an important crop in Thailand which gives export income 50-70 million baht per year. The average capacity of peppercorn production is 3.5 million tons per year. Moreover, the product price tends to consistently increase. Peppercorn can be used not only herbal ingredient in a variety of foods but also used as food flavor. Drying is the method for food preservation for a long time. The desiccated product can be kept for a long period without rot. Therefore, there are many studies about drying technique up to date. Drying is the process in removing moisture from product by evaporation. Generally, hot air is widely used as media of drying process. Heat is transferred to the product while the moisture is removed. The rate of drying process is up to the temperature difference between hot air and the product, relative humidity and air velocity. Basically, high temperature air with low relative humidity is preferable for quick drying process. A fluidized bed dryer permits comfort and very efficient drying to very low moisture content due to uniform temperature distribution and a large contact area between solid and gas. The objective of this work is to investigate the drying kinetics of peppercorns. More specifically, the aim of this work was to study the effect of both drying techniques (fluidized-bed and turbulator techniques) on the progress of the drying process. The inlet air temperature was 90癈, the relative air humidity 63% and the superficial air velocities varied from about 2.2-3.3 m/s. The experimental results show that effect of superficial air velocity on drying behaviors is marginal for the fluidization technique but significant for the turbulator drying technique while the turbulator drying performed better than original fluidization technique at high superficial velocity.