Process Modeling and Simulation of the Radiation in the Electric Arc Furnace

Abstract

In this paper, an approach to the enhancement of a dynamic process simulation model of an electric arc furnace (EAF) is described by improving the modeling and simulation of the heat transfer especially by radiation within the EAF. The presented work is a continuation of the work of Logar, Dov zan, and Skrjanc on modeling the heat and mass transfer and the thermochemistry in an EAF. The modeling and simulation of the heat transfer within the EAF is improved by including the electrode in the model and considering the convective and radiative heat transfer to and from the electrodes, for example, by modeling the surface of the electrodes as a radiative surface. Furthermore, the modeling of the melting geometry is improved and implemented in the model in a way to allow for more geometric variability of the scrap meltdown simulation. As a consequence, the view factor calculation within the model is implemented a new way, allowing for a fast and efficient matrix calculation. Finally, the modeling of the thermal radiation of the gas phase is revised to include gas species previously added to the model and to consider emissivity, absorptivity and transmittance of the gas phase as well as the dust load. Figure 2. Exemplary temperature profile of the electrode and homogeneous temperatures of selected sections. www.advancedsciencenews.com www.steel-research.de steel research int. 2018, 89, 1700487

Calculation of View Factors in Electric Arc Furnace Process Modeling

“…Such process models that include a detailed treatment of the radiative heat exchange have been published by MacRosty et al, [ 4 ] Logar et al, [ 5 ] and, based on that, Meier et al, [ 6 ] Saboohi et al, [ 7 ] Fathi et al, [ 8 ] and Opitz et al [ 9 ] All of these models are based on similar assumptions regarding the geometrical conditions during meltdown, using a cone‐frustum‐shaped void in the scrap moving down and expanding outward as the electrode bores down toward the melt and the charge melts. Three phase furnaces are approximated with a single central electrode and electric arc.…”

Development of an Electric Arc Furnace Simulator Based on a Comprehensive Dynamic Process Model

“…Validation of the EAF process model using extensive measured process data from a 140 t direct current (DC) furnace can be found in previous publications where the thermochemistry of the gas phase [34] and liquid phases [39], the behavior of different carbon carriers [33], the heat transfer [32], as well as the performance of the complete model [37], were evaluated thoroughly, which is not reproduced here. The model has also been tested with data from additional furnaces including both alternating current (AC) and DC technology and has given satisfactory results after adjustment of the empirical parameters during preliminary research.…”

“…For the charging of scrap baskets, the amount and composition of scrap, slag formers, Relevant phenomena such as heat exchange through radiation and direct contact, phase changes and mass transfer between zones, chemical reactions, as well as the change in geometry during meltdown, are considered in the model. Simulation results have been validated using extensive data from industrial furnaces [32][33][34]37,39].…”

“…Several such models are available in the literature such as those of Bekker et al [10][11][12] and MacRosty et al [13][14][15] who introduced some of the simplifications and assumptions that Logar et al based their model on, as well as several others that have been published with a varying degree of detail [16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31]. Both Meier et al [32][33][34][35][36][37] and Fathi et al [38] have published models developed on the basis of the work of Logar et al [3,[5][6][7][8]. With the exception of Logar et al, all these models rely on predetermined input from measured data and, as far as can be determined from the published information, no other simulators that provide direct feedback and control for the user are available.…”

“…The model and simulator presented here are based on a further development of the model proposed by Meier [39]. Although the general model structure and most of the assumptions and simplifications from Logar et al [3,[5][6][7][8]] remain, the model has been adjusted for a different solver algorithm [36] and substantially modified [32][33][34]36,37,39] making it one of the most comprehensive and up-to-date EAF process models currently available. The differences compared to the model published by Logar et al include a more efficient numerical method for solving the model equations [36], increased detail in the gas phase with additional species and reactions [34,37], a more comprehensive model of the radiative heat transfer considering the influence of the gas phase [32,37], the treatment of different carbon carriers [33], and the refinement of the thermochemical model for the interaction of slag and melt with each other as well as the injected oxygen and carbon [39].…”