Modeling and Simulation of the Off-gas in an Electric Arc Furnace

Abstract

The following paper describes an approach to process modeling and simulation of the gas phase in an electric arc furnace (EAF). The work presented represents the continuation of research by Logar, Dovzˇan, and Sˇkrjanc on modeling the heat and mass transfer and the thermochemistry in an EAF. Due to the lack of off-gas measurements, Logar et al. modeled a simplified gas phase under consideration of five gas components and simplified chemical reactions. The off-gas is one of the main continuously measurable EAF process values and the off-gas flow represents a heat loss up to 30 pct of the entire EAF energy input. Therefore, gas phase modeling offers further development opportunities for future EAF optimization. This paper presents the enhancement of the previous EAF gas phase modeling by the consideration of additional gas components and a more detailed heat and mass transfer modeling. In order to avoid the increase of simulation time due to more complex modeling, the EAF model has been newly implemented to use an efficient numerical solver for ordinary differential equations. Compared to the original model, the chemical components H 2 , H 2 O, and CH 4 are included in the gas phase and equilibrium reactions are implemented. The results show high levels of similarity between the measured operational data from an industrial scale EAF and the theoretical data from the simulation within a reasonable simulation time. In the future, the dynamic EAF model will be applicable for on-and offline optimizations, e.g., to analyze alternative input materials and mode of operations.

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

“…Within this paper, parts of the enhancements of the reimplemented and already further developed [10][11][12][13] model from Logar et al [1][2][3][4][5] are presented. The calculation of the radiation within the EAF is described.…”

“…Compared to the implementation according to Logar et al, [1,3] the view factors VF 22 , VF 33 , VF 34 , VF 43 as well as all the view factors VF i6 and VF 6j associated with the electrode surface are calculated in the EAF model to complete the view factor matrix in Equation 10:…”

“…Through further separate and joint developments of the model from Logar et al, [1][2][3][4][5] the components H 2 , H 2 O, and CH 4 were included in the gas phase. [10][11][12][13] So, all major off-gas components are considered. Furthermore, the chemical reactions were enhanced by three equilibrium reactions and the dissociation of water.…”

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

“…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].…”