Numerical Modeling of Direct Reduction of Iron-Ore in Fluidized Beds with CFD-DEM

Sprache des Vortragstitels:

Englisch

Original Tagungtitel:

10th International Conference on Multiphase Flow

Sprache des Tagungstitel:

Englisch

Original Kurzfassung:

The thermochemical reduction of iron-ores has gained much attention in the past decades as it is a core process in the ironand steelmaking industries. Fluidized beds and moving bed reactors are some of the procedures used to reduce the iron-ore
efficiently. Due to harsh conditions inside the reactors, accesibility is limited, therefore simulation tools are utilized in their
research. One such tool uses the coupling of Computational Fluid Dynamics (CFD) and the Discrete Element Method (DEM)
method, where the reacting gas is calculated in the Eulerian side and the iron-ore particles in the Lagrangian side. In this
work, the common types of mathematical models that represent the reduction of iron-ores, the shrinking particle and the
unreacted core models, are added into the CFDEM coupling library. The shrinking particle model is used to determine the
communication framework between the CFD and DEM. The unreacted core model is then used to calculate the reduction of
iron-ore. Firstly, it is validated with comparing the simulations of a single hematitic iron-ore for various gas compositions with
available experiments. Particle parameters such as the particle porosity, pore diameters as well as the critical kinetic parameters
such as the equilibrium constants, activation energies and frequency factors are calibrated according to the single ore reduction.
With the modified parameters, the reduction of iron-ore inside a fluidized bed is calculated and validated with experiments that
take the different reduction steps for the iron-ore reduction into account. The kinetic model proves to be in good relation with
the experimental data for various operating conditions.