One-dimensional phosphate flash dryer model for design application

The present paper studies the design of a bench scale flash dryer for phosphate particles using a one-dimensional steady-state model. The model was based on the two-fluid theory considering momentum, heat, and mass transfer between the solid and gas phases for a dilute gas-solid suspension flow and for which solid interactions were neglected. The set of coupled nonlinear differential equations of the model was solved using a Runge-Kutta method. A sensitivity analysis for inlet air and solid velocity, air temperature and pressure, air and solid moisture content, and for tube diameter and length was performed to design phosphate bench scale flash dryer to reduce the solid moisture content from 18 to 2%. An analysis of the results enabled choosing the appropriate conditions for experiments of phosphate drying for a hot air stream inlet of 200 degrees C, in a flash dryer of 1.7 m length and 0.2 m internal diameter.