The drying of alpeorujo, a waste product of the olive oil mill industry

Alpeorujo is a waste product of the olive oil mill industry that still has a significant oil content. Before extracting the remaining oil with hexane, the moisture content of the wet waste product has to be reduced from approximately 65% to about 8%. To develop standards for dryer design and operation, an extensive study was carried out at laboratory scale. A drying tunnel was built to calculate drying curves, volatile emissions, ignition temperatures, and solids degradation at high temperatures while drying under several different operating conditions. The results of this experimental work allowed us to develop a useful drying model for designing new dryers and for assessing the behaviour of existing ones. (C) 1999 Elsevier Science Ltd. All rights reserved.