Design, development and evaluation of a continuous plug flow fluidized bed dryer

In this study, a laboratory scale continuous plug flow fluidized bed dryer was designed and constructed. A backward-curved centrifugal fan with a 4 kW electromotor was selected based on the maximum pressure drop in the minimum fluidization state and the ability to produce the velocity required for fluidization of the most granular agricultural materials. The fluidization chamber was a rectangular cuboid with 100, 8, and 40 cm in length, width and height, respectively. The solid feed system was consisted of a bin, a screw conveyor, and an electromotor-gearbox. The uniform fluidization and appropriate drying confirmed that it is possible to develop the industrial prototype of the dryer based on the laboratory one. The decrease of solid moisture content along the dryer length was nonlinear. Increasing the inlet solid mass flow rate at constant inlet gas temperature and weir height increased the solid moisture content at the outlet and along the length of the dryer.