Thin Layer Drying of Orange Skin Paste for Biofuel Production: Drying Characteristics and Mathematical Modelling
Authors: Agbede OO, Adebiyi AO, Oke EO, Arinkoola AO, Ogunleye OO, Agarry SE, Babatunde KA, Osuolale FN
Huge amount of orange waste is generated during juice extraction and this could be converted to bioenergy through pyrolysis, gasification or combustion. However, improved efficiency of these processes requires drying, hence, the drying characteristics of orange skin paste was investigated in this study. Orange skin wastes were crushed and then dried to constant mass in a hot air oven dryer (at 80, 120 and 140 oC), solar dryer and direct sunlight. Twelve thin layer models were fitted to the drying data. Hot air oven drying of orange skin paste took place in the falling rate period with effective moisture diffusivity (Deff) which varied from 7.0 x 10-9 to 1.8 x 10-8 m2 s-1. The temperature dependence of Deff was suitably described by an Arrhenius-type equation and an activation energy of 16.1 kJ mol-1 was required for drying the orange skin paste. The specific energy required for hot air drying was 846 – 1475 kJ/g. Open sun and solar drying of orange skin paste also occurred in the falling rate period with Deff values of 2.0 x 10-9 and 2.16 x 10-9 m2 s-1, respectively. The Midilli-Kucuk, Logarithmic and Midilli-Kucuk models best fitted the hot air oven, open sun and solar drying, respectively.
Affiliations: Department of Chemical Engineering, Ladoke Akintola University of Technology, Ogbomoso, Nigeria.
Keywords: Orange Skin Paste, Drying, Effective Moisture Diffusivity, Activation Energy, Thin Layer Model
Published date: 2019/12/30