Desolventizing kinetics of oilseed meals with superheated hexane

Abstract

The desolventization kinetics of oilseed meals with superheated solvent was investigated experimentally and theoretically. A bench-scale equipment was designed and built to measure continuously the rate of mass loss and the solid temperature during desolventization of meal particles. Experiments were carried out with sunflower and soy meals using superheated hexane vapor as desolventizing fluid and temperatures ranging from 90 C to 135 C. Experimental data were used to determine the vapor-particle heat transfer coefficient under different conditions, which compare reasonably with predictions of dimensionless correlations for solid particles. A relatively simple mathematical model to represent the desolventization kinetics of individual meal particles, based on heat transfer in a receding front system, was developed. The model was used to analyze the effect of temperature, particle diameter, shrinkage and mass transfer on desolventizing rate. Prediction of desolventization kinetics of sunflower and soy meals compared satisfactorily against experimental results at different temperatures.