ABSTRACT
Mechanical thermal expression (MTE) is a novel drying technique that evolved from the relatively old technique called hydrothermal dewatering. During hydrothermal dewatering, solid material of a defi nite structure is heated to ∼300°C using water, steam, oil, or some other heating medium. Because suffi cient pressure is maintained to prevent boiling, liquid water is expelled from the solid matrix and then separated once cooling and pressure release are completed. The energy requirements for hydrothermal dewatering are signifi cantly lower than those for evaporation, being in the order of 1600-1800 kJ/kg of removed water. However, the plant cost, batch nature of the process, and impurities that could be extracted from some materials into process water at such high temperatures have prevented hydrothermal dewatering from wide industrial application.
