Mathematical modelling and verification of open sun drying of cotton seeds

Abstract

Researchers have carried out the kinetics of various agro products for open sun drying, but research articles still need to address such analysis for cotton seeds. Open sun drying of cotton seeds has been experimentally investigated and presented in this paper. Shorting of cotton seeds was carried out to collect appropriate samples in current research work. Cotton seeds were found to have a nearly ovoid shape with an average radius of 2 to 2.5 mm. The initial moisture content of cotton seeds was estimated to be 14.65% wet-basis using the hot air oven method. During drying, the reduction in the mass of cotton seeds was measured at every one-hour time interval. From this data, it was observed that drying occurred with a falling rate period. Drying data were fitted with 10 mathematical models available in the literature. Multi-regression analysis in Excel-solver equation was performed to obtain values of constants and coefficients of these models. Coefficient of determination (R2), reduced chi-square (χ2) and root mean square error were taken as criteria for the selection of the best drying model. The diffusion approach and models by Verma et al. were chosen as the most suitable drying models for open sun drying of cotton seeds. Effective diffusivity was estimated and found within the range suggested in the literature.