Mathematical model of direct reduction shaft furnace and its application to actual operations of a model plant

Abstract

The shaft furnace process provides the greatest energy efficiency and the highest productivity among all direct reduction processes. Most shaft furnaces producing sponge iron, however, have been designed empirically up to the present. In order to optimize operations a mathematical model has been developed to be applied to shaft furnace design. The model, whose reduction rate equations are derived from the three-interface model, involves both mass and heat balances. The model's rate parameters were determined according to the parameter fitting method, so that calculated values might agree, as closely as possible, with measured values in an experimental shaft furnace with an inside diameter of 0.25 m and a reduction zone height of 2.7 m. Commercial applicability of the mathematical model was also confirmed by simulations in an actual shaft furnace.