Centrifugal-Granulation-Assisted thermal energy recovery towards low-carbon blast furnace slag treatment: State of the art and future challenges

Wu, Jian; Tan, Yu; Wang, Hong; Zhu, Xun; Liu, Qiang

doi:10.1016/j.apenergy.2022.119835

Cited by 20 publications

(4 citation statements)

References 133 publications

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“…Dry centrifugal granulation of molten slag has gradually become a research hotspot among researchers worldwide due to its ability to address issues in conventional wet treatment processes and recover waste heat from the slag, apart from other advantages. For this reason, a considerable amount of published literature has explored the continuous flow and breakup processes of the free surface liquid film on spinning discs or cups [3]. Rauscher et al [4] employed theoretical analysis to derive an approximation of the analytical solution for the radial velocity and thickness of the liquid film.…”

Section: Introductionmentioning

confidence: 99%

Computational Fluid Dynamics Numerical Simulation on Flow Behavior of Molten Slag–Metal Mixture over a Spinning Cup

Wang,

Pan,

Zhao

et al. 2024

Processes

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Centrifugal granulation technology using a spinning cup opens a potential way to recycle steel slag that is currently difficult to reuse. The objective of this research was to study the flow characteristics of a molten slag–metal mixture that was produced during smelting reduction in molten steel slag, passing over a spinning cup, so as to explore the feasibility of using centrifugal granulation technology to treat the steel slag. This was achieved by developing and implementing a computational fluid dynamics (CFD) model that incorporated free-surface multiphase flow to predict the thickness of the liquid slag film at the edge of the spinning cup (slag film thickness for short), which was an important parameter for estimating the size of the slag particles resulting from centrifugal granulation of the molten slag–metal mixture. The influences of various relevant parameters, including spinning cup diameter, slag feeding rate, cup spinning speed, etc., on the slag film thickness were analyzed. Additionally, hot experiments on centrifugal granulation of a molten slag–metal mixture were conducted to verify the results of the numerical simulations. The experimental results indicated a progressive reduction in the Sauter mean diameter of the slag particles as the metallic iron content in the slag increased. Specifically, when the iron content rose from 5% to 15% at a cup spinning speed of 2500 RPM, the Sauter mean diameter decreased by 13.77%. The numerical simulation results showed that the slag film thickness had a positive relationship to the slag feeding rate but a negative relationship to the spinning cup diameter and the cup spinning speed. Furthermore, the ratio between the mean slag particle diameter and the slag film thickness decreased nearly linearly with the increase in the metallic iron content in slag, with the average ratio being approximately 4.25, and this relationship was useful for estimating the slag particle size from the slag film thickness. Therefore, the present research results can provide theoretical guidance for the industrial application of spinning cup centrifugal granulation technology to effectively treat and recycle steel slags.

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Section: Introductionmentioning

confidence: 99%

Computational Fluid Dynamics Numerical Simulation on Flow Behavior of Molten Slag–Metal Mixture over a Spinning Cup

Wang,

Pan,

Zhao

et al. 2024

Processes

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“…The working principles and status of the aforementioned DSG examples have been well reviewed by Barati et al [8] and Zhang et al [1] Notably, centrifugalgranulation-assisted thermal energy recovery (CGATER) is gaining the spotlight for its potential to recover the heat from BF slag without hampering the hydrate activity of BF slag. [9][10][11] The CGATER has been intensively tested at laboratory [9] and more recently, important CGATER trials were carried out at pilot scales in Australia, [12,13] Europe, [14] and China. These preeminent efforts make the CGTAER stand out from the available DSG methods; it is regarded as the leading technology for low-carbon slag treatment in the iron making industry.…”

Section: Introductionmentioning

confidence: 99%

High‐Temperature Thermophysical Property Characterization of Molten Blast Furnace Slag: A Critical Reviews

Liu

et al. 2023

steel research int.

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Centrifugal granulation‐assisted thermal energy recovery (CGATER) remains the leading technology for the iron and steel industry to enable the low‐carbon treatment of high‐temperature blast furnace (BF) slag. Accurate knowledge of the thermophysical properties of BF slag is pivotal for the commercialization of the CGATER. However, it presents a formidable task to obtain these quantities due to the extremely high temperature of molten BF slag (≈1500 °C). To date, the thermophysical properties of BF slag have not been well characterized yet. Herein, five typical thermophysical properties including density, viscosity, surface tension, thermal conductivity, and emissivity are scrutinized with emphasis on the experimental measurements and empirical estimates. The working principles of these measurement methods are briefly overviewed and their merits and demerits are highlighted. It is noted that density, viscosity, and surface tension have been intensively studied; the quantities can be estimated with moderate uncertainty. However, the thermal conductivity and emissivity of BF slag are less tackled, mainly because of the scarcity of measurement tools at high temperatures. In the future, innovative measurement tools tailored for high‐temperature materials are essential, not only for enriching the thermophysical property database of BF slag but also for paving the way toward characterizing other complex high‐temperature melts.

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“…Molten slags such as blast furnace slag (BFS) or steel slag at 1500 °C or above hold a large share of the waste heat in ISI. It is very critical to recover the high-temperature waste heat from the molten slags, which thus requires efficient heat transfer between the slag and the coolant (such as air) for further integration with well-established heat utilization technologies [1]. Particularly, high cooling rates are imperative to form the glassy phase slag, which is available for cement clinker production.…”

Section: Introductionmentioning

confidence: 99%

Modeling the Phase-Change Cooling of Molten Slag Granule: An Appraisal

Xiang,

Wu,

et al. 2023

Preprint

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An accurate understanding of slag cooling characteristics is essential for efficient slag heat recovery. Herein, we established multiple cases including different assumptions, such as dimensions, boundary conditions, width ratios, radiation models, and turbulence models to quantify the extent of error associated with these assumptions. An area-weight angle sampling method was adopted to evaluate the accuracy of assumptions. The results reveal the significant error attributed to dimensions and radiation, with RMSE and MAPE of 235.14 K and 41.30% for the 2D planar model, and 198.60 K and 25.66% for the model without radiation. Notably, when the width ratio exceeds 4, the influence of boundary conditions on cooling characteristics becomes negligible. This present work provides a benchmark model to quantify the error of assumptions and thus enables more accurate yet efficient modeling for phase-change cooling for molten slag at ultrahigh temperatures.

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Centrifugal-Granulation-Assisted thermal energy recovery towards low-carbon blast furnace slag treatment: State of the art and future challenges

Cited by 20 publications

References 133 publications

Computational Fluid Dynamics Numerical Simulation on Flow Behavior of Molten Slag–Metal Mixture over a Spinning Cup

Computational Fluid Dynamics Numerical Simulation on Flow Behavior of Molten Slag–Metal Mixture over a Spinning Cup

High‐Temperature Thermophysical Property Characterization of Molten Blast Furnace Slag: A Critical Reviews

Modeling the Phase-Change Cooling of Molten Slag Granule: An Appraisal

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