Discrete Element Method-Based Hybrid Compartment Model of a Rotary Dryer for Fertilizer Production

This work introduces a compartment model based on a discrete element method (DEM) model. The DEM model determines the residence times (RTs) of particles in the active (in contact with air) and passive zones. The extracted RT is combined with the heat and mass transfer models into a compartment model, where particles are modeled by employing a population balance. Heat and mass transfer models contain efficiency coefficients that are modeled with surrogates generated from a reduced set of experiments. The resulting surrogate models are validated with additional experiments in an industrial facility. It accurately reproduces the heat and mass transfer in the dryer (+/- 10% of relative error in temperature prediction) and provides a guess of the distribution of the properties of the particles (e.g., moisture content and temperature) across particle sizes and locations within the dryer.