ORALS

The large scale industrial processes involved in Iron and Steelmaking are very complex in nature and very much challenging to understand. A lot of modeling and simulation efforts have been made by numerous workers in the past to have an insight of the process and predict the behavior of the process due to changes in operating parameters and raw material conditions. The iron and steelmaking processes involve dynamic interaction between various phases namely slag, metal, gas and solid, existing altogether at very high temperatures, along with other coupled phenomena like dissolution of solid charge/scrap and fluxes. The overall modeling of such complex reactor involves chemical reaction thermodynamics calculations at interface as well as mass transport rates considering the nature and behavior of fluid flow and diffusion processes.Such complex process could be modeled very effectively by coupling of slag/metal, metal/gas and gas/solid reactions using multicomponent mixed transport-control theory [1]. In the overall sense, the thermodynamics and mass transport based kinetic limitations inside the reactor are integrated together in an intelligent manner depending upon the mixing behavior and mass transport characteristics across various regions inside the reactor. A multireactor-based approach and multicomponent mixed control method as explained above was used to model BOF Steelmaking process as well as MIDREX Process. The macro programming capability of FactSage [2] was used to program such models in an innovative manner which was also validated by using the data from Steel Plant (JSW Steel Ltd.). In BOF Steelmaking Process, This approach was used to study the decarburization rates and their contributions coming from the jet impact (hot-spot) zone, slag–metal–gas emulsion, and bath boiling for different levels of mixing in the metal bath by variation of other operating parameters [3,4]. In MIDREX Process the model was developed by considering the process as a counter current reactor consisting of multiple conceptual reactors. The fraction of gas being utilized in each reactor zone is estimated using the kinetic considerations of the process. The overall kinetic effect involving the effect of mass transfer control in the gas, and solid product, along with chemical reactions at the interface of the unreacted solid surface were considered. The model was used to predict the carbon content, production rate and metallization for the given set of input variables [5].This approach of modeling the large scale reactor process is very much effective tool as explained by the examples of BOF and MIDREX processes. The effect on CO2 emissions and energy consumption due to various possible changes in the process operating strategies, parameters and raw materials could be studied very effectively with the help of such innovative models where they may act as an efficient guiding tool.

References:
[1] Robertson, D.G.C.; Deo, B.; Ohguchi, S. Multicomponent Mixed-Transport-Control Theory for Kinetics of Coupled Slag/Metal and Slag/Metal/Gas Reactions: Application to Desulphurization of Molten Iron. Ironmak. Steelmak. 1984, 11, 41–56.
[2] FactSage. Center for Research in Chemical Thermodynamics, Polytechnique de Montreal, Canada. Available online: www.factsage.com
[3] Prasenjit Singha and Ajay Kumar Shukla, "Contribution of Hot-Spot Zone in Decarburization of BOF Steel-Making: Fundamental Analysis Based upon the FactSage-Macro Program", Metals, 2022, vol. 12(4),p. 638. https://www.mdpi.com/2075-4701/12/4/638/htm
[4] Prasenjit Singha and Ajay Kumar Shukla, "Dynamic Basic Oxygen Steelmaking Process and Its Industry Validation", JOM-Journal of Metallurgy, 2023, vol. 75, p. 3890–3899. https://link.springer.com/article/10.1007/s11837-023-06003-1
[5] Sunil Yadav, Srishilan C, and Ajay Kumar Shukla “Thermodynamic Model of MIDREX Ironmaking Process using FactSageTM and Macro Facility", Metallurgical and Materials Transactions B, 2023. (Accepted on September 20). https://link.springer.com/article/10.1007/s11663-023-02928-9