Quantification of iron vaporization and fragmentation during direct oxidation in moderate oxygen concentrations
Year: 2026
Type: article
Abstract: The formation of submicron particles by evaporation of iron and subsequent condensation of iron oxides is an aspect of potential concern in the direct oxidation of iron, proposed as a zero-carbon technology for energy storage and transport when combined with ore reduction. In this work, 63–75 μm iron particles have been burnt in a high temperature atmosphere with 4–16% O 2 , a range of conditions representative of most regions in a combustion chamber operated with air. The particulate emissions were classified by size, and presented three different modes: the ‘coarse’ particles, resulting from the evolution of the fuel particles; an intermediate mode, roughly 1–25 μm, formed by fragments of explosions of the larger particles and sharing their morphology and composition (magnetite + hematite); and a mode of submicron particles, composed of Fe 2 O 3 (mostly maghemite). The fraction of mass in the last two modes increases monotonically with the oxygen concentration (particle temperature), up to 2.1 and ∼ 0.8% in the total particulate emissions, respectively. A 0-D evaporation model considering only vapor diffusion fails to fit the trend determined experimentally from the amount of submicron particles; based on the vapor pressure vs. particle temperature for either liquid Fe or FeO, a steeper trend was expected, which suggests that further work on the subject is still necessary. The experimental vaporization yields reported here point to the need of efficient particle retention systems in iron-fueled power plants.
Source: Fuel
Authors: S. Jiménez, M.C. Mayoral
Institution: Instituto de Carboquímica
Language: English
Subfield: Biomedical Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $4,330
Award: G8484862723
OpenAlex ID: W7154501452