Process Modeling and Simulation of Biochar Usage in an Electric Arc Furnace as a Substitute for Fossil Coal

Abstract

Increasing demands on the electric arc furnace (EAF) with regard to sustainability and energy efficiency are leading to various technological innovations. To reduce the carbon footprint of the steel production in EAFs, fossil coal can be substituted by biochar as investigated within the GreenEAF research projects. Palm kernel shells (PKS) are used for industrial long-term trials and showed no negative impact on product quality or energy consumption and are technically feasible, but led to different reaction behavior. For further investigations on PKS usage in the EAF, the charging of biomass is implemented in a dynamic EAF process simulation model. As one of the biggest differences of PKS in comparison to fossil coal, the chemical energy of the higher volatile content is earlier available during the heat. The model considers the chemical composition of the type of coal and distinguishes between volatiles and fixed carbon. The simulation results and measurements of the averaged off-gas composition are showing the increased reaction rate of PKS. The results are obtained with the same model parameterization as for anthracite charging. In the future, the model will be applicable to analyze various modes of operation with regard to optimized energy and resource efficiency.

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].…”

Review on the Use of Alternative Carbon Sources in EAF Steelmaking

“…Meier et al [52] conducted simulations of the use of biomass in the EAF based on the case of one of the steel plants in the GreenEAF2 project. They used a dynamic EAF process model to simulate complete heats implementing biomass (palm kernel shells) as a charge carbon substitute.…”