Mathematical Modelling of Drying Characteristics of Coconut Slices

Abstract

Mathematical modelling is one of the most important Engineering considerations for the effective representation of drying processes. Therefore, the drying behaviour of the coconut slices was modelled using non-linear regression (fitting existing mathematical models). The three thickness of the coconut samples (4 mm, 8 mm and 12 mm) were dried using laboratory oven under five different temperature (40C, 50C, 60C, 70C and 80C) and constant air velocity (1 m s-1). Drying properties such as moisture content, moisture ratio, drying rate, drying time, effective moisture diffusivity coefficient (Deff) and activation energy of the process was used to define the behaviour of the coconut slices, the experimentally observed moisture ratios were fitted into fifteen (15) existing thin-layer mathematical model to forecast the behaviour of the coconut slices during process. The result of the modelling showed that the modified Henderson and pabis, Page and Peleg model had the most acceptable level of accuracy in predicting the drying behaviour of the coconut slices at 4mm, 8mm and 12mm, respectively. The obtained values for the effective moisture diffusivity ranges between 6.06×10−11 𝑚2 𝑠-1 and 3.16×10−10 𝑚2 𝑠-1 for 4mm thickness; 5.46×10−10 𝑚2 𝑠-1 and 1.44×10−9 𝑚2 𝑠-1 for 8mm thickness; 5.97×10−10 𝑚2 𝑠-1 and 2.83×10−9 𝑚2 𝑠-1 for 12mm thickness, whilst the activation energy ranges between 27.44892 and 27.563 𝑘𝐽 𝑚𝑜𝑙-1 for 4mm thickness; 27.45371 and 27.53017 𝑘𝐽 𝑚𝑜𝑙-1 for 8mm thickness; 35.64817 and 35.84369 𝑘𝐽 𝑚𝑜𝑙-1 for 12 mm. Therefore, the Modified Henderson and Pabis, Page and Peleg thin-layer mathematical models were chosen for the best prediction of the dehydration behaviour of coconut slices of 4 mm, 8 mm and 12 mm thickness respectively.

Keywords

• Coconut
• Oven drying
• Drying characteristics
• Mathematical models
•  Oven drying

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