A generalized correlation for the estimation of moisture removal in fruits and grains during hot air drying

Drying of food and grain material for removal of moisture is an important aspect in preserving them or for extraction of oil. It is a complex process involving both heat and mass transfer. The present work is aimed at developing a simple mathematical model with governing differential equations and proper boundary conditions for spherical shaped food material to determine the rate of moisture removal. The differential equations are solved using numerical technique with the help of a computer Program and the results are presented in graphical form. The variation of temperature within the seed with respect to time for various drying medium temperatures considering the partial pressure of water vapor in the drying medium are presented. The rate of moisture removal with respect to time for different convective environment conditions and varying resistance within the seed is also presented. A generalized correlation to determine the moisture rate removal as a function of Fourier number, Biot number and Mass transfer Parameter is developed for estimation of time required for heating under different hot air conditions for various spherical shaped fruits or grains. This non-dimensional correlation is helpful in quick estimation of time for drying of any seed and hence would be useful in the Agro Industry.