Modeling of iron ore pellet induration in a pilot-scale pot-grate furnace.

摘要

In this work, a mathematical model of the pilot scale iron ore pellet induration furnace is presented. The validity of the model has been verified by performing separate experiments of subprocesses: drying, firing and cooling. The experiments were performed in such a way that the phenomena of heat transfer, drying and chemical reactions could be studied separately. To do this, the green pellets were first dried, then heated to elevated temperatures at which the coke combustion commences and the pellet strength begins to increase. Finally, the pellets were cooled by passing ambient air across the bed. Samples were taken at different levels of the pot-grate to measure the percentages of carbon and magnetite within the pellets, the porosity and the strength, mechanical resistance, of the pellets.;The pellet induration model is based on the equations describing the phenomena of heat and mass transfer, gas flow, drying, combustion of coke and oxidation of magnetite. The experiments were simulated by solving the differential equations. The pellet bed was divided into differential height elements and the phenomenological equations were solved by numerical methods. This type of model is very useful in many applications such as designing of new plants, evaluating the effectiveness of different process parameters and training the operators and engineers. In addition, it can also serve as a module for on-line control of the moving grate furnace operations.