Assessment of Air Velocity and Temperature Profiles inside a Continuous Powder Dryer with Inclined Plates

Drying is a quite relevant unit operation, widely used in many industrial fields such as pharmaceutical, chemical, metallurgical, polymers, food and others. Although drying process is already established in most of industrial equipment, there is still many phenomena that need to be explained, mainly in continuous powder dryer. The efficiency of drying processes depends on the flow pattern of the air, the geometry of the dryer, and the location and design of the air inlet and outlet channels. In this study, a steady state, three-dimensional, multiphase experimental and CFD modeling of a vertical continuous powder dryer with inclined plates is carried out to study the effect of the air velocity and temperature profiles on the humidity of the powder in the outlet of the dryer. Results show that the air entrance should be located in front of the inclined plates at a speed to avoid drag of powder. It was found that it is necessary to introduce the total air flow in several inlets along the length of the dryer instead of using one inlet. It increases the density of the powder bulk and improves the mass and heat transfer between the powder and the drying air. Regarding the temperature, it is necessary to rise the inlet temperature of the air on the dryer to avoid large temperature changes which changes the relative humidity of the air as well which is the main parameter that increase the velocity of drying.