Three-dimensional computational fluid dynamics analysis of an electric submerged arc furnace

K Karalis,A Xenidis,N Karkalos,Ν Ntallis,G S E Antipas,N Karalis

doi:10.1038/s41598-021-96085-1

Abstract

A computational fluid dynamics (CFD) method is proposed to analyze the operation of a submerged electric arc furnace (SAF) used in ferronickel production. A three-dimensional mathematical model was used for the time-dependent solution of the fluid flow, heat transfer and electromagnetic phenomena. The slag's physical properties, which play a crucial role in the SAF operation, were previously determined using classical molecular dynamics simulations and empirical relationships. The analysis revealed that the main slag properties affecting SAF operation are density, viscosity and electrical conductivity—the latter two being mutually dependent. The high electrical conductivity values of the slag favor melting via the high Joule heat produced within the slag region. Calculation of the dimensionless Péclet and Reynolds numbers revealed that the slag velocities play a decisive role in heat transfer and further indicate that the slag flow is laminar. The average slag velocity calculated 0.0001 m/s with maxima in the vicinity of the electrodes.

Highlights

A computational fluid dynamics (CFD) method is proposed to analyze the operation of a submerged electric arc furnace (SAF) used in ferronickel production
SAFs typically operate at temperatures as high as 2000 K6 under the effect of Joule heating maintained by several self-backing Söderberg e lectrodes[7] which are continuously consumed via submersion into a slag m elt[1,7]
The aggregate FeNi/slag σ value can be inputted into Eq (5), solving the system of Eqs. (5) and (10) in order to obtain the spatial distribution of the electric potential V, on the provisions that B is zero as there is no magnetic field external to the SAF rig, B0 is by definition zero [Eq (6)] and b is negligible as previously shown by u s8

Summary

Introduction

A computational fluid dynamics (CFD) method is proposed to analyze the operation of a submerged electric arc furnace (SAF) used in ferronickel production. Slag and ferronickel EC define the association between the chemical composition of the ore feed and the energy consumption of the SAF; this association constitutes the most substantial reductive smelting metric—exclusively determined by trial and e rror1—and an intrinsically multi-scale modeling problem which has not been addressed so far To this extent, we previously reported the first step of a multi-scale approach, regarding the first principles’ prediction of mesoscale slag EC to within 10% of the experimentally determined value (81.1 S/m at 1773 K) for an industrial-grade reductive smelting implementation[6]. We apply the pre-determined properties (based on the atomic order, atomistic modeling)[3,4,6,13] on the development of a three-dimensional mathematical model to examine the effect of the main operational parameters (applied voltage, current density etc.) in the process efficiency In the former models, the distribution of temperature, velocity, and density regarding the slag electrical and thermal conductivity was determined. Based on the obtained results, correlations based on the slag composition to the overall power consumption can be made

Methods

Results

Conclusion