Mathematical modeling and computational simulation of gas-solid reactions in moving bed: application to the direct reduction process of iron ore

Abstract

Non-catalytic gas-solid heterogeneous reactions have a large importance in many industrial processes. These systems are complex because they are inherently transient, involving mass and heat transport phenomena associated with chemical reactions and structural changes of the solid over time. The heterogeneities of the gas phase flow distribution and changes in the solid morphology of these systems characterizes the complexity in multiscale. Various mathematical models reported in the literature have been based on several simplifications. For these reasons, the present study proposes the development of a more rigorous mathematical model, coupling the representation of the non-catalytic reactions between gas and solid particles with models for gas flow in moving bed. Computational Fluid Dynamics (CFD) will be used to describe the chemical and physical transformations of the direct reduction process of iron ore. This process consists of a sequence of reactions between a reducing gas and the solid iron ore pellets in moving bed reactors. The best configurations of the pellet will be investigated through structural parameters of this raw material, such as size and porosity. In order to determine the optimum process conditions, parameters such as flow rate, temperature and composition of the reducing gases will also be evaluated. The model will be validated with experimental data obtained in laboratory scale at the Technological Research Institute (IPT), as well as data from industrial plants from the literature. This research is part of the project "Institutional Development Plan in the Digital Transformation Area: Advanced Manufacturing and Intelligent and Sustainable Cities (PDIP)" of the Technological Research Institute of São Paulo (Process FAPESP 2017/50343-2), research topic: Modeling of Biophysical-Chemical Processes. (AU)