Mathematical Modeling of Pneumatic Char Injection in a Direct Reduction Rotary Kiln

A one-dimensional steady-state mathematical model is proposed for direct reduction process in rotary kilns akin to the SL/RN process. The model takes into account pneumatic coal char injection from the discharge end of the kiln to supplement the heat availability. The model is based on material and energy conservation principles, and the empirical equations for kinetics and heat transfer are obtained from the literature. Predictions are carried out for both iron oxide reduction and ilmenite beneficiation processes. Improvement in the performance was predicted with pneumatic char injection.