Session: 11-08-02: Multiphase Flows and Applications II

Paper Number: 166622

CFD Modeling of Steel-Slag Interactions in Industrial EAF Refining Operations 

Over the past decades the steel industry has experienced a rapid increase in the adaptation of the electric arc furnace (EAF). In particular, 70% of steel production in the U.S. at present is achieved through the EAF route. In addition to the energy efficiency and flexibility of EAF operations, EAFs produce up to 55% less carbon emissions than traditional blast furnace – basic oxygen furnace processes, which makes EAF a key technology for the decarbonization of steel industry. Most EAF operations include a preheating stage, a melting stage and a refining stage. During the preheating stage, the scrap loaded in the furnace is preheated by burners included at the walls of the furnace. After this stage, the electrodes are activated and the melting of the charge is carried out by the arc heating and the burners. The refining stage is the last stage of the EAF operation. In this stage, the burners turn to lance mode to inject oxygen which reacts with the molten steel to reduce carbon content and impurities. In this stage, the desired chemistry and temperature of the steel bath is achieved before tapping. The overall EAF operation includes complex physical-chemical processes in a harsh environment that makes data collection very difficult. Computational fluid dynamics (CFD) could provide important insight into the EAF operations by describing the flow dynamics, reaction rates, phase change and thermal behavior of the system throughout the domain. The complex processes in EAF, however, require advance CFD models to simulate real EAF operations at actual scales. In this study, a state-of-the-art CFD methodology is introduced to simulate the refining stage of EAFs under real conditions. The CFD model extends a previous methodology that integrated a coherent jet model and a refining model. Namely, the coherent jet model is applied first to obtain the flow velocity profiles and mass flow rates of the oxygen jets when these impinge the molten bath. These variables are then used to compute the cavities formed by the jets on the liquid steel. The new CFD methodology, based on the Volume of Fluid (VOF) approach, includes the calculated cavities in the CFD domain in addition to the molten steel, slag and gas regions. The CFD model accounts for the formation of oxides in the molten bath as oxygen is injected, and the migration of oxides to slag and gas regions. The new CFD methodology is able to model the slag foaming process and the interaction of steel and slag during refining. Current application of the refining model in actual operations is discussed, as well as potential applications for modeling of alternative injectants in the refining stage to further reduce carbon emissions of EAF operations.

Presenting Author: Orlando Ugarte Purdue University Northwest

Presenting Author Biography: Orlando Ugarte was born in Ancash, Peru. He obtained a PhD in Mechanical Engineering from West Virginia University. Currently, he works in the Center for Innovation through Visualization and Simulation (CIVS) in Purdue University Northwest as Research Scientist. Previous job titles include Post Doc Research Associate in Purdue University Northwest and Postdoctoral Fellow in Georgia Tech. His main scientific interests include CFD modeling, combustion, multi-phase flows and compressible flows.

Authors:

Orlando Ugarte Purdue University Northwest
Tyamo Okosun Purdue University Northwest
Chenn Zhou Purdue University Northwest