Liquid Drying by Solid Desiccant Materials: Experimental Study and Design Method

摘要

The use of consumable solid desiccant materials for organic liquid dehydration is very current in refinery or chemistry processes, especially when the water concentration is very low ($<$1000?ppm). In spite of its common use, the kinetics of liquid drying by solid desiccants is not well known, and scale-up of industrial drying processes using such materials is always problematic. In this study, the kinetics of drying of two organic liquids, dipropylene-glycol (DPG) and toluene, with some classical “type-1” desiccant materials is analysed. The experiments were done on three different scales, by using different appropriate apparatus: a laboratory stirred reactor, a small pilot and a semi-industrial pilot. The results show that dehydration kinetics is driven by a strong mass transfer limitation. Based on these results, a simple model is developed in order to design industrial drying columns from pilot data. This model is able to predict the time evolution of the water content at the outlet of the column, and the resulting simulations are in good agreement with experiments.