Last modified: 2016-06-03
Abstract
In the present work a coupled Euler-Lagrange approach is used to model the dynamics of a particulate phase and its interaction with hot gas injection into particle bed reactors. The proposed numerical approach is based on the Discrete Element Method (DEM) to model the granular phase. The in-house DEM solver has been extended to account for heat and mass transfer within the gas phase by coupling it with the governing Navier-Stokes equations in the Eulerian Computational Fluid Dynamics (CFD) gas model. This coupling has been done by using the CFD OpenFoam library. As a result the numerical simulation framework called the Extended Discrete Element Method (XDEM) has being developed. The present case uses the XDEM as a numerical tool to study a small scale blast furnace reactor where hot gas at hight speed is injected laterally into a packed bed of coke particles.
The nature of the blast furnace operation includes several types of flow, a packed bed of solids descending, liquid dripping and gas with powder ascending through the packed bed. The interaction between solids and different fluid phases represents a challenging phenomenon for numerical simulation. In order to represent more accurately such processes the XDEM code has being adapted and several features like particle gasification, chemical reaction and diverse particle shapes have been implemented. The XDEM Euler-Lagrange approach showed the ability to track the positions of the coke particles in the simulation domain allowing an in-depth study of the particle-gas interaction. Since hot air at 1200 K was injected, the effects of gasification, reactions inside the particles, and shrinking were considered. Comparison of measurements for coke gasification particles showed a good agreement with experimental data.