Investigation on the Kinetics of Iron Ore Fines Reduction by CO in a Micro-fluidized Bed

Chen, Hongsheng; Zheng, Zhong; Shi, Wan-Yuan

doi:10.1016/j.proeng.2015.01.308

Cited by 32 publications

(14 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…To ensure the minimized external diffusion effect, a gas flowrate of 250 mL/min was chosen in this study. Compared to the results from the study of Chen et al [26], the external diffusion effect on the reduction of iron ore fines could be removed when the gas flowrate was 300 mL/min. Their experimental temperature was set to 700 • C. In this study, the temperature was much higher than the value in the literature [26], and the increasing reduction temperature also enhanced the diffusion of gas diffusion from the ambient phase to the particle surface, causing diffusion to proceed more quickly.…”

Section: Effect Of Gas Flowratecontrasting

confidence: 68%

A Kinetic Study on the Reduction of Single Magnetite Particle with Melting Products at High Temperature Based on Visual and Surface Analytical Techniques

Shen

Sun

Zhu

et al. 2021

Metals

View full text Add to dashboard Cite

In this study, the reduction characteristics of single magnetite particles with melting products at high temperature were investigated by using visualization and surface analytical techniques. The morphology evolution, product type, reduction degree, and reduction rate of single magnetite particles during the reduction process were analyzed and compared at different reduction temperatures. The results showed that the morphology of the product formed at the reduction temperature of 1300 °C was a mainly nodular structure. When the reduction temperature was above 1400 °C, the products were melted to liquid and flowed out of the particle to form a layered structure. The morphology of the melted products finally transformed to be root-like in structure on the plate around the unmelted core. Raman spectroscopy was used to determine the product types during the reduction process. Experiments studying the effects of gas flowrate and particle size on the reduction degree were carried out, and the results showed that both increasing the temperature and gas flowrate can increase the reduction degree. The internal/external diffusion influence can be ignored with a particle size smaller than 100 μm and a gas flowrate more than 200 mL/min. However, owing to the resistance of the melted products to gas diffusion, the reduction rates at 1400 and 1500 °C were reduced significantly when the reduction degree increased from 0.5 to 1.0. Conversely, the formation of the liquid enlarged the contact area of the reducing gas and solid–liquid and further increased the reduction degree. The kinetics parameters, including average activation energy and pre-exponential factor, were calculated from the experimental data. The reduction kinetics equation of the single magnetite particle, considering the effect of melted products is also given in this study.

show abstract

Section: Effect Of Gas Flowratecontrasting

confidence: 68%

A Kinetic Study on the Reduction of Single Magnetite Particle with Melting Products at High Temperature Based on Visual and Surface Analytical Techniques

Shen

Sun

Zhu

et al. 2021

Metals

View full text Add to dashboard Cite

show abstract

“…Accordingly, the activation energy is chosen based on literature reported values. Chen et al 41 reported the activation energy as 60.9 kJ/ mol for FeO reduction to Fe using iron ore fines in a microfluidized bed. Liu et al 42 Figure 5 shows the experimental and modeling results of 60 s 0.5% CO/60 s 0.9% O 2 lean-rich cycling experiments.…”

Section: Experimental and Modeling Resultsmentioning

confidence: 99%

“…Accordingly, the activation energy is chosen based on literature reported values. Chen et al reported the activation energy as 60.9 kJ/mol for FeO reduction to Fe using iron ore fines in a microfluidized bed. Liu et al studied the reduction kinetics of wustite by H 2 or CO, and estimated an activation energy for FeO to Fe is (64 ∓ 8) kJ/mol.…”

Section: Experimental and Modeling Resultsmentioning

confidence: 99%

Dynamic Oxygen Storage Capacity of Ceria-Zirconia and Mn_0.5Fe_2.5O₄ Spinel: Experiments and Modeling

Zhou

Harold

Luss

2021

Ind. Eng. Chem. Res.

View full text Add to dashboard Cite

A combined experimental and modeling study of dynamic oxygen storage capacity (DOSC) of ceria-zirconia (CZO) and Al2O3-supported Mn0.5Fe2.5O4 (MFO) spinel using CO and H2 as reductants is conducted to provide understanding of the redox performance of CZO and MFO under periodic reduction–oxidation cycling conditions. Particular attention is placed on fast cycling (cycle time of several seconds) encountered in emission control applications. Fixed bed reactor experiments with CZO show that during reduction (or oxidation) a transition in rate-controlling regimes occurs, from a reaction-controlled process during the first ∼20 s to a slower diffusion-controlled process. The classical shrinking-core model is successfully applied to describe the transient DOSC performance. In contrast, for MFO with its higher oxygen storage capacity (OSC), reduction is confined to oxygen within the first surface layer of the dispersed spinel crystallites. A progressive model is developed that is capable of capturing the DOSC performance under both a long cycle (60 s) and short cycle (1–2 s). The reaction steps of MFO spinel are determined by CO-TPR and involve two sequential steps: Mn0.5Fe2.5O4 → Mn0.5Fe2.5O3 and Mn0.5Fe2.5O3 → Mn0.5Fe2.5O0.5. The kinetic parameters obtained from the fixed-bed reactor are applied to model the modulation performance in a Pt/Pd-spinel dual-layer monolith with CO as the reductant. The model-predicted results show that the periodic reduction–oxidation on MFO during fast cycling is limited to the first reaction step (Mn0.5Fe2.5O4 → Mn0.5Fe2.5O3). The DOSC modeling can be applied to the analysis and identification of other oxygen storage materials.

show abstract

“…In the third stage, FeO is reduced to Fe. 29 Therefore, in the reduction reaction of Fe 2 O 3 , the transition points between the stages are X I Fe2O3 = 0.11 and X II Fe2O3 = 0.3. For distinguishing and identifying the transition points, differential method has been used in previous studies.…”

Section: Differential Analysis Of the Conversion In Reductionmentioning

confidence: 99%

“…The results show that, at different stages, the reaction process of Fe 2 O 3 was: Fe 2 O 3 → Fe 3 O 4 →FeO → Fe, which is consistent with the mechanism proposed in previous studies. 29 Furthermore, the changes in conversion during the ash reduction were also analyzed. As ash contains Fe 2 O 3 and CaSO 4 , and the emphasis was put on which one of them reacted first.…”

Section: Process Analysis Of the Reduction Reactionmentioning

confidence: 99%

High Iron and Calcium Coal Ash As the Oxygen Carrier for Chemical Looping Combustion

Lin

Liu

Jin

et al. 2018

Ind. Eng. Chem. Res.

View full text Add to dashboard Cite

The potential of Zhundong’s coal ash as a novel oxygen carrier (OC) in chemical-looping combustion (CLC) was evaluated in a thermogravimetric analysis (TGA) under both the CO/Ar and air atmospheres. A single reduction–oxidation cycle was carried out in the TGA reactor to determine the optimum reaction temperature, which was 1123 K. The cyclic stability and agglomeration tendency of ash also was evaluated by consecutive redox cycles. On the basis of the kinetic analysis, the apparent activation energy of ash was about 26–29 kJ/mol and the reduction process of ash was divided into three stages. The reaction control steps for these stages were gas diffusion, diffusion and kinetics, and kinetics, respectively. Besides, the reactions in the first and second stages corresponded to the reduction of Fe2O3 to Fe and CaSO4 to CaS. In the third stage, the reaction occurred between the CaS and CaSO4.The products of the equilibrium reaction between CO and ash were obtained using Factsage (software), while the transition products from the reduction of ash were determined by X-ray diffraction (XRD). The main reactants in ash were Fe2O3 and CaSO4. Because of sintering and particle agglomeration, the actual percentage of oxygen release (22%) was less than the theoretical value (26%). In addition, after some reactions CaSO4 was converted to MgOCa3O3Si2O4.

show abstract

Investigation on the Kinetics of Iron Ore Fines Reduction by CO in a Micro-fluidized Bed

Cited by 32 publications

References 14 publications

A Kinetic Study on the Reduction of Single Magnetite Particle with Melting Products at High Temperature Based on Visual and Surface Analytical Techniques

A Kinetic Study on the Reduction of Single Magnetite Particle with Melting Products at High Temperature Based on Visual and Surface Analytical Techniques

Dynamic Oxygen Storage Capacity of Ceria-Zirconia and Mn_0.5Fe_2.5O₄ Spinel: Experiments and Modeling

High Iron and Calcium Coal Ash As the Oxygen Carrier for Chemical Looping Combustion

Contact Info

Product

Resources

About

Investigation on the Kinetics of Iron Ore Fines Reduction by CO in a Micro-fluidized Bed

Cited by 32 publications

References 14 publications

A Kinetic Study on the Reduction of Single Magnetite Particle with Melting Products at High Temperature Based on Visual and Surface Analytical Techniques

A Kinetic Study on the Reduction of Single Magnetite Particle with Melting Products at High Temperature Based on Visual and Surface Analytical Techniques

Dynamic Oxygen Storage Capacity of Ceria-Zirconia and Mn0.5Fe2.5O4 Spinel: Experiments and Modeling

High Iron and Calcium Coal Ash As the Oxygen Carrier for Chemical Looping Combustion

Contact Info

Product

Resources

About

Dynamic Oxygen Storage Capacity of Ceria-Zirconia and Mn_0.5Fe_2.5O₄ Spinel: Experiments and Modeling