A novel mechanical vapor compression vacuum belt drying system: Model development, experimental verification and performance prediction

Abstract

Lower energy consumption has always been the important goal of vacuum belt drying processing of food and drug. A novel mechanical vapor compression vacuum belt drying system was proposed and established in this paper. Experimental results show that it greatly reduced energy consumption (33.20–66.33 %) by means of mechanical vapor compression, however, the steam compressor had the greatest exergy destruction (5.87 kW) and lowest exergy efficiency (13.50 %), which should be prioritized optimization. Based on the experiments, the correction factors were linearly fitted to modify the original equations of heat transfer coefficient, coefficient of performance, specific water evaporation, and specific energy consumption, respectively, the mean absolute relative deviation between the developed models and experiments was from 1.73 to 4.40 %. The optimal range of process parameters was obtained by performance prediction, such as the heat transfer temperature difference (7–11 °C), drying pressure (32.5–42.5 kPa), heat transfer temperature difference (18–24 °C) and compression ratio (2.3–3.2).Research of this paper provides the technical support for the design optimization and engineering application of mechanical vapor compression vacuum belt drying system.