TY - GEN A1 - Ali, Mohammed Liaket A1 - Mehlhose, Sven A1 - Fradet, Quentin A1 - Riedel, Uwe T1 - An experimental and CFD study of the iron ore fixed bed structure and its influence on the direct reduction process T2 - Proceedings of the 14th European Conference on Industrial Furnaces and Boilers N2 - The current circumstances of global warming, improved energy efficiency, and the higher suitability of Direct Reduced Iron (DRI) in Electric Arc Furnaces (EAF) for steel production necessitate a transition in the iron and steelmaking process from the traditional blast furnace/basic oxygen furnace to the more sustainable and eco-friendly direct reduction process. This reduction can be effectively studied in a fixed bed configuration, which bridges the gap between fundamental investigations on a single pellet and industrial shaft furnaces. While an average porous media model may be used to simulate the fixed bed reactor, this approach fails to account for the impact of intra- and inter-pellet fluid dynamics as well as heat and mass transfer. To accurately represent the geometric structure of iron ore pellet beds, an experimental construction must be accompanied by a particle-resolved CFD model. This article is divided into successive steps. The first step consists in the experimental construction of iron ore beds with different pellet size distributions (10-12.5 mm and 12.5-16 mm) and of the calculation of the bulk bed porosity and radial average bed porosity. The discrete element method (DEM) is further used to computationally reconstruct random packed beds of 0.5 kg industrial pellets based on the experimental data of pellet size distributions. A 3D domain is created using particle position data from the previous step, and pellets and voids are meshed at different refinement levels. Finally, CFD simulations are carried out to investigate the reduction of iron oxide pellets using H2 as a reducing gas in a fixed bed, considering available experimental data for model validation. The effect of three different bed structures on the overall conversion degree of iron ore is examined. This approach allows for successful modeling of a fixed bed using experimental input and investigation into the potential effects of the bed structure on the overall conversion during the direct reduction of the iron ore pellets. Y1 - 2024 UR - https://elib.dlr.de/204601/ ER - TY - GEN A1 - Ali, Mohammed Liaket A1 - Mehlhose, Sven A1 - Fradet, Quentin A1 - Riedel, Uwe T1 - Particle-resolved computational modeling of hydrogen-based direct reduction of iron ore pellets in a fixed bed. Part II: Influence of the pellet sizes and shapes T2 - International Journal of Hydrogen Energy Y1 - 2024 U6 - https://doi.org/10.1016/j.ijhydene.2024.08.384 SN - 0360-3199 VL - 86 SP - 1401 EP - 1413 PB - Elsevier BV ER - TY - GEN A1 - Ali, Mohammed Liaket A1 - Fradet, Quentin A1 - Riedel, Uwe T1 - Particle-resolved computational modeling of hydrogen-based direct reduction of iron ore pellets in a fixed bed. Part I: Methodology and validation T2 - International Journal of Hydrogen Energy Y1 - 2024 U6 - https://doi.org/10.1016/j.ijhydene.2024.09.028 SN - 0360-3199 VL - 87 SP - 332 EP - 343 PB - Elsevier BV ER - TY - GEN A1 - Fradet, Quentin A1 - Ali, Mohammed Liaket A1 - Riedel, Uwe T1 - Development of a porous solid model for the direct reduction of iron ore pellets T2 - steel research international Y1 - 2022 U6 - https://doi.org/10.1002/srin.202200042 SN - 1869-344X SN - 1611-3683 VL - 93 IS - 12 ER - TY - GEN A1 - Ali, Mohammed Liaket A1 - Fradet, Quentin A1 - Riedel, Uwe T1 - Kinetic mechanism development for the direct reduction of single hematite pellets in H2/CO atmospheres T2 - steel research international N2 - Increasing interest in the direct reduction process of iron ore has revived investigations on gaseous and heterogeneous iron oxides’ kinetics. Despite extensive studies on the reduction of iron oxides with pure hydrogen or syngas, the development of a generic reduction mechanism for iron oxides is still lacking. The conventional shrinking core model hardly distinguishes between transport and reaction processes, leading to biases or even errors in the kinetic models. In the present study, a porous solid model, which solves mass balances of the individual gas‐phase species and solid ones assuming spherical symmetry, is used for developing a heterogeneous kinetic mechanism accounting for different iron oxidation stages (Fe2O3, Fe3O4, FeO). It also accounts for carbon accumulation and cementite formation to model the carburization phenomena when using carbon‐containing reducing agents like syngas. The proposed generic mechanism successfully reproduces 49 experimental data sets from the literature for single iron Y1 - 2022 U6 - https://doi.org/10.1002/srin.202200043 SN - 1611-3683 VL - 93 IS - 12 PB - Wiley ER -