Visualizing particle melting and nanoparticle formation during single iron particle oxidation with multi-parameter optical diagnostics

Li, Tao; Heck, Franziska; Reinauer, Felix; Böhm, Benjamin; Dreizler, Andreas

doi:10.1016/j.combustflame.2022.112357

Cited by 32 publications

(14 citation statements)

References 17 publications

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“…As the temperature reaches the melting point of iron at 1811 K, the iron particle melts, starting from the surface. If the initial particle is non-spherical, a clear shape transition to a sphere can be observed with high magnification imaging [36]. During melting, the luminosity intensity of the particle shows a clear plateau.…”

Section: Single Iron Particle Combustionmentioning

confidence: 99%

“…While single particle experiments dominate the literature, there has been some progress in particle group investigation. In recent years there have been significant advancements in iron combustion experiments by research groups such as Aldén [31][32][33], de Goey [34,35], and Dreizler [36,37].…”

Section: Solid Fuel Typesmentioning

confidence: 99%

“…The fused quartz glass ensures optical access in all directions, and the excellent flatness of the flame allows for precise determination of particle heating points. While the Hencken and McKenna burners are typically used as calibration burners, the LFR was originally designed for solid fuel combustion experiments by Dreizler and Böhm's group [70], and has been applied in single particle [36,81,83] and particle group [122][123][124] combustion experiments.…”

Section: Flow Reactorsmentioning

confidence: 99%

“…After melting, the temperature of the iron particle continues to rise until it reaches a peak temperature near 3000 K, which depends on the particle size and gas phase compositions. The high temperature approaches or may even exceed the iron boiling point, resulting in the formation of vapor phase iron and iron oxides in the vicinity of the iron core, which can lead to the possible formation of nanoparticles [36]. Subsequently, the particle cools down due to heat loss to the environment, although full oxidation might not be achieved during this stage, which is referred to as reactive cooling.…”

Section: Single Iron Particle Combustionmentioning

confidence: 99%

See 3 more Smart Citations

Particle-resolved optical diagnostics of solid fuel combustion for clean power generation: a review

Li,

Geschwindner,

Dreizler

et al. 2023

Meas. Sci. Technol.

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Chemical energy carriers are crucial for addressing challenges that arise from the time lag, large distances, and temporal fluctuations in renewable energy production, which lead to unbalanced energy production and demand. However, the thermochemical utilization of chemical energy carriers such as solid fuels must be widely decarbonized to achieve a climate-neutral circular economy, despite remaining important for reliable electricity generation and stable economics. To accomplish this, extensive fundamental research is required to understand the underlying chemical and physical processes that can potentially be realized on an industrial scale. This paper reviews optical diagnostics used for particle-level combustion studies for clean power generation applications. Specifically, we focus on particle-resolved optical experiments for oxy-fuel coal combustion, biomass combustion, and utilization of iron in a regenerative oxidation-reduction scheme. We summarize previous studies categorized by the type of fuels, used reactors, investigated parameters, and experimental methodology. To provide a shared understanding, phenomenological aspects of the multistage combustion process at the particle level are outlined using examples of bituminous coal and iron particle burning in hot gas, respectively. A selection of experimental studies is highlighted, with a particular methodological focus on the measurement of relevant quantities at the particle level. These representative examples address relevant parameters, including particle number density, particle size and shape, surface temperature, ignition and combustion time, gas flame structure, gas temperature and species, nanoparticle formation, gas velocity, and particle dynamics. Finally, open issues and unsolved problems that require further effort to improve diagnostics for solid fuel combustion studies are discussed.

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Section: Single Iron Particle Combustionmentioning

confidence: 99%

Section: Solid Fuel Typesmentioning

confidence: 99%

Section: Flow Reactorsmentioning

confidence: 99%

Section: Single Iron Particle Combustionmentioning

confidence: 99%

See 2 more Smart Citations

Particle-resolved optical diagnostics of solid fuel combustion for clean power generation: a review

Li,

Geschwindner,

Dreizler

et al. 2023

Meas. Sci. Technol.

Self Cite

View full text Add to dashboard Cite

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“…To design and improve real-world iron-fuel burners, an in-depth understanding of the fundamentals underlying the combustion of single iron particles is required. In the past few years, the number of more detailed experimental − and theoretical studies − regarding the combustion of single iron particles has increased drastically. In this early research on iron particle combustion, a good agreement between experiments and theoretical models for low gas temperature (300 K) and low oxygen concentration cases (up to X O2 = 0.21) was obtained.…”

Section: Introductionmentioning

confidence: 99%

Effect of Fe–O ReaxFF on Liquid Iron Oxide Properties Derived from Reactive Molecular Dynamics

Thijs,

Kritikos,

Giusti

et al. 2023

J. Phys. Chem. A

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As iron powder nowadays attracts research attention as a carbon-free, circular energy carrier, molecular dynamics (MD) simulations can be used to better understand the mechanisms of liquid iron oxidation at elevated temperatures. However, prudence must be practiced in the selection of a reactive force field. This work investigates the influence of currently available reactive force fields (ReaxFFs) on a number of properties of the liquid iron–oxygen (Fe–O) system derived (or resulting) from MD simulations. Liquid Fe–O systems are considered over a range of oxidation degrees Z O , which represents the molar ratio of O/(O + Fe), with 0 < Z O < 0.6 and at a constant temperature of 2000 K, which is representative of the combustion temperature of micrometric iron particles burning in air. The investigated properties include the minimum energy path, system structure, (im)miscibility, transport properties, and the mass and thermal accommodation coefficients. The properties are compared to experimental values and thermodynamic calculation results if available. Results show that there are significant differences in the properties obtained with MD using the various ReaxFF parameter sets. Based on the available experimental data and equilibrium calculation results, an improved ReaxFF is required to better capture the properties of a liquid Fe–O system.

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Carrier-Phase DNS of Ignition and Combustion of Iron Particles in a Turbulent Mixing Layer

Luu,

Shamooni,

Kronenburg

et al. 2024

Flow Turbulence Combust

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Three-dimensional carrier-phase direct numerical simulations (CP-DNS) of reacting iron particle dust clouds in a turbulent mixing layer are conducted. The simulation approach considers the Eulerian transport equations for the reacting gas phase and resolves all scales of turbulence, whereas the particle boundary layers are modelled employing the Lagrangian point-particle framework for the dispersed phase. The CP-DNS employs an existing sub-model for iron particle combustion that considers the oxidation of iron to FeO and that accounts for both diffusion- and kinetically-limited combustion. At first, the particle sub-model is validated against experimental results for single iron particle combustion considering various particle diameters and ambient oxygen concentrations. Subsequently, the CP-DNS approach is employed to predict iron particle cloud ignition and combustion in a turbulent mixing layer. The upper stream of the mixing layer is initialised with cold particles in air, while the lower stream consists of hot air flowing in the opposite direction. Simulation results show that turbulent mixing induces heating, ignition and combustion of the iron particles. Significant increases in gas temperature and oxygen consumption occur mainly in regions where clusters of iron particles are formed. Over the course of the oxidation, the particles are subjected to different rate-limiting processes. While initially particle oxidation is kinetically-limited it becomes diffusion-limited for higher particle temperatures and peak particle temperatures are observed near the fully-oxidised particle state. Comparing the present non-volatile iron dust flames to general trends in volatile-containing solid fuel flames, non-vanishing particles at late simulation times and a stronger limiting effect of the local oxygen concentration on particle conversion is found for the present iron dust flames in shear-driven turbulence.

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Visualizing particle melting and nanoparticle formation during single iron particle oxidation with multi-parameter optical diagnostics

Cited by 32 publications

References 17 publications

Particle-resolved optical diagnostics of solid fuel combustion for clean power generation: a review

Particle-resolved optical diagnostics of solid fuel combustion for clean power generation: a review

Effect of Fe–O ReaxFF on Liquid Iron Oxide Properties Derived from Reactive Molecular Dynamics

Carrier-Phase DNS of Ignition and Combustion of Iron Particles in a Turbulent Mixing Layer

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