Through‐circulation drying of vegetable materials. I.—brewers' spent grain

Abstract

Abstract Brewers' spent grain has been dried by through circulation of hot air in single layers and in beds up to 8 in. in depth. The effect of air temperature (100–220° F) and velocity (6.63–22‐2 lb. of dry air/sq. ft./min.) on the drying rates of single layers has been studied. It has been found that the drying rate is proportional to the total moisture ratio of the layer, and that both temperature and velocity have a marked effect on the proportionality constant. A method of predicting drying times in deep beds, based on the results of the single‐layer tests, is proposed and discussed. The accuracy of this method has been checked against actual drying times in deep beds and found to be within +‐11.5%. The resistance of deep beds to the passage of air has been investigated briefly.