Modelling of an ironmaking melter gasifier unit operation with multicomponent/multiphase equilibrium calculations

The blast furnace is the traditional ironmaking process for the production of hot metal with high iron content. The Corex® and Finex® processes are the main alternative technological solutions in this field of industrial activity. Their main advantages are focused in better economic and environmental characteristics. The melter gasifier is the most important unit operation of both processes. The aim of this paper is to describe the development and implementation of a predictive mathematical model of a multizone melter gasifier. The process modelling and simulation software used for this task is the gPROMS ModelBuilder. For the calculation of the hot metal/slag mixture chemistry, the Gibbs minimisation routines for multicomponent/multiphase systems were implemented through FactSage and ChemApp. A communication scheme between gPROMS and FactSage/ChemApp was established. The validation of this methodology took place by comparing the basic iron making reactions against literature. Special attention was given in the numerical stability by designing a dedicated initialisation strategy. The agreement between simulation results and plant data proved to be successful for the main components (iron, carbon, calcium oxide, magnesium oxide, aluminium oxide, sulphur). Deviation appeared for the silicon and manganese components. This work contributes in making accurate predictions for the hot metal and slag chemistry based on thermodynamic first principles. The reliable calculation presents the opportunity to apply rigorous optimisations that can lead to higher process efficiency. This reflects the potential of reducing fuel consumption, thus leading to lower environmental emissions.