Influence of Particle Size Distribution on Agglomeration/defluidization of Iron Powders at Elevated Temperature

Zhong, Yiwei; Gao, Jintao; Wang, Zhi; Guo, Zhen

doi:10.2355/isijinternational.isijint-2016-487

Cited by 14 publications

(13 citation statements)

References 33 publications

(45 reference statements)

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“…The relationship between the physical properties of iron ore fines and the fluidity was systematically evaluated by the degree of compression method, Hausner method 97) and the counting method. Y. W. Zhong et al 98) studied the effects of the particle size distribution (narrow, Gaussian, binary and flat) on the high-temperature de-fluidization behavior and fluidization characteristic of iron powders. And found that the particle adhesion of bed materials was dependent strongly on particle size distribution.…”

Section: Iron Ore Characteristicmentioning

confidence: 99%

A Review on Prevention of Sticking during Fluidized Bed Reduction of Fine Iron Ore

et al. 2020

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The fluidized bed ironmaking technology has attracted the attention of many researchers for decades as a direct reduction ironmaking method with many advantages. This process has been applied as a pretreatment method in many non-blast furnace ironmaking processes. However, the sticking problem hindered its development greatly. Defining the essential cause of sticking, and fundamentally solving this problem are the key steps encountered by this process. The research works related to the prevention of sticking problem during fluidized bed reduction of fine iron ore are comprehensively summarized in this article. The causes of sticking, the influencing factors of sticking and the solution of sticking are firstly discussed, followed by the analysis on the possible development direction of future fluidized bed ironmaking technology.

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Section: Iron Ore Characteristicmentioning

confidence: 99%

A Review on Prevention of Sticking during Fluidized Bed Reduction of Fine Iron Ore

et al. 2020

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“…The results also show that the Fe 2 O 3 and MnO 2 powders do not have high stability under the operating conditions adopted; the efficiency of the process decreases from the maximum value of 72.27% reached at the third cycle to 60.50% at the sixth cycle. This instability is highly likely to be found in agglomeration/sintering phenomena of Fe and Mn, which cause a reduction of the reactive surface of the bed 51 . As a result, a smaller amount of magnetite is reduced and, therefore, a lower amount of Fe is oxidized.…”

Section: Resultsmentioning

confidence: 99%

Pure hydrogen production by steam‐iron process: The synergic effect of MnO ₂ and Fe ₂ O ₃

et al. 2020

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Summary In the energy transition from fossil to clean fuels, hydrogen plays a key role. Proton‐exchange membrane fuel cells (PEMFCs) represent the most promising hydrogen application, but they require a pure hydrogen stream (CO < 10 ppm). The steam iron process represents a technology for the production of pure H2, exploiting iron redox cycles. If renewable reducing agents are used, the process can be considered completely green. In this context, bio‐ethanol can be an interesting solution that is still not thoroughly explored. In this work, the use of ethanol as a reducing agent in the steam iron process will be investigated. Ethanol, at high temperature, decomposes mainly in syngas but can also form coke, which can compromise the process effectiveness, reacting with water and producing CO together with H2. In this work, the deposition of coke is avoided by controlling the duration of the reduction step; in fact, the data demonstrated that coke deposition is significantly dependent on reduction time. Tests were carried out in a fixed bed reactor using hematite (Fe2O3) as raw iron oxide adopting several reduction times (7 minutes‐25 minutes), which correspond to different amount of ethanol fed (5 mmolC2H5OH/gFe2O3‐17,95 mmolC2H5OH/gFe2O3). The effect of the addition of MnO2 to increase the reduction degree of iron oxides was explored using different amount of MnO2 (10 wt% and 40 wt% with respect to Fe2O3). The tests were performed at fixed temperatures of 675°C and atmospheric pressure. The optimization of the reduction time, in the chosen operating condition, performed only with Fe2O3, shows that, feeding an amount of 5 mmolC2H5OH/gFe2O3, coke deposition is avoided and, therefore, a pure H2 stream in oxidation is obtained. The addition of MnO2 leads to increased H2 yield and process efficiency, confirming its positive effect on the reduction degree of the solid bed. A reaction pathway to demonstrate the synergic effect of Fe2O3 and MnO2 in the reduction step was proposed in this article.

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“…However, the particle size distribution (PSD) and the average particle size change, as well as the change of the fines content when the catalysts have different PSDs, are mixed with the existing catalyst bed. Therefore, it is necessary to consider the relative influence of the fine particles on coarse ones in the overall bed as the fines content varies [7,18], because it is difficult to quantify the PSD change of the bed. Regarding the PSD change, several studies [6,19] introduced a concept of relative spread in the PSD, but the results for its effect were not shown.…”

Section: Effect Of Fcat or Additive Make-up On Bed Fluiditymentioning

confidence: 99%

“…A better guidance for effective catalyst make-up for keeping or restoring the bed fluidity is required, because the catalyst make-up costs may be higher. The proposed Equation (2) is believed to provide a PSD management guide for making the fluidization quality good in the unit by providing the desired PSD information of fresh catalysts for the make-up [18]. On the basis of the available findings and results, the following suggestion would likely be useful in quickly restoring the bed fluidity in various fines or catalyst loss occasions.…”

Section: Guidance For Control Of Bed Fluiditymentioning

confidence: 99%

Effect of Fines Content on Fluidity of FCC Catalysts for Stable Operation of Fluid Catalytic Cracking Unit

2019

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Effect of fines content (weight % of particles with diameter less than 45 μm) on bed fluidity was determined to get a base for good fluidization quality in the fluid catalytic cracking (FCC) unit. The fines content in equilibrium FCC catalysts (Ecat) from commercial units were controlled by adding or removing the fines to simulate commercial situation. To get the fluidity values (Umb/Umf) of seven different FCC catalysts (2 Ecats and 5 fresh catalysts) and their mixture, minimum fluidization velocity (Umf) and minimum bubbling velocity (Umb) were measured in a fluidized bed reactor (0.05 m ID). The fluidity decreased with loss of fines content and increased with increments of makeup of fresh catalysts or additive with the controlled fines content. The fluidities of catalysts increase with increases of normalized particle diameter variation by the fines addition. The obtained fluidities have been correlated with the fines contents and the catalyst and gas properties. The proposed correlation could guide to keep good catalyst fluidity in the FCC unit.

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Influence of Particle Size Distribution on Agglomeration/defluidization of Iron Powders at Elevated Temperature

Cited by 14 publications

References 33 publications

A Review on Prevention of Sticking during Fluidized Bed Reduction of Fine Iron Ore

A Review on Prevention of Sticking during Fluidized Bed Reduction of Fine Iron Ore

Pure hydrogen production by steam‐iron process: The synergic effect of MnO ₂ and Fe ₂ O ₃

Effect of Fines Content on Fluidity of FCC Catalysts for Stable Operation of Fluid Catalytic Cracking Unit

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Influence of Particle Size Distribution on Agglomeration/defluidization of Iron Powders at Elevated Temperature

Cited by 14 publications

References 33 publications

A Review on Prevention of Sticking during Fluidized Bed Reduction of Fine Iron Ore

A Review on Prevention of Sticking during Fluidized Bed Reduction of Fine Iron Ore

Pure hydrogen production by steam‐iron process: The synergic effect of MnO 2 and Fe 2 O 3

Effect of Fines Content on Fluidity of FCC Catalysts for Stable Operation of Fluid Catalytic Cracking Unit

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Pure hydrogen production by steam‐iron process: The synergic effect of MnO ₂ and Fe ₂ O ₃