A kinetic comparison between microwave heating and conventional heating of FeS-CaO mixture during hydrogen-reduction

Amini, Ahmadreza; Ohno, Ko Ichiro; Maeda, Takayuki; Kunitomo, Kazuya

doi:10.1016/j.cej.2019.05.226

Cited by 27 publications

(11 citation statements)

References 34 publications

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“…According to literature, MW heating has mainly thermal effects on reaction kinetics. For instance, hot spots generated during the MW treatment of solid beds enhance the reaction rate as their temperature is significantly higher than the average bed (or bulk) temperature (Amini et al, 2019;Amini et al, 2021). The hot spots can form microcracks inside the solid materials and enhance internal mass transfer.…”

Section: Kinetics Of Gas/liquid-solid Reactionsmentioning

confidence: 99%

“…For instance, MWs selectively heat some components of iron oxide minerals, generating a temperature gradient between different components within an ore particle. Accordingly, micro-cracks are generated throughout the ore, enhancing gas diffusion into the ore, and improving the apparent kinetics of the reduction reaction (Amini et al, 2019).…”

Section: Kinetics Of Gas/liquid-solid Reactionsmentioning

confidence: 99%

“…In the MW heating approach, however, heat is generated in the body of certain phases (commonly solid particles) owing to the high penetration depth of MWs and their interaction with dielectric material loaded in the reactors. MWs cannot directly heat the gas phase due to their negligible interactions with this phase (Hamzehlouia et al, 2018;Amini et al, 2019). Therefore, a considerable temperature gradient between the solid particles (either inert or catalyst) and fluid suppresses the fluid-phase side reactions, favors the production of desired chemicals, and likely leads to higher selectivity and conversion (Stefanidis et al, 2014;Hamzehlouia et al, 2018;Amini et al, 2019;Robinson et al, 2020).…”

Section: Introductionmentioning

confidence: 99%

“…MWs cannot directly heat the gas phase due to their negligible interactions with this phase (Hamzehlouia et al, 2018;Amini et al, 2019). Therefore, a considerable temperature gradient between the solid particles (either inert or catalyst) and fluid suppresses the fluid-phase side reactions, favors the production of desired chemicals, and likely leads to higher selectivity and conversion (Stefanidis et al, 2014;Hamzehlouia et al, 2018;Amini et al, 2019;Robinson et al, 2020). The rapid and selective features of MW heating also decrease the treatment time and energy loss during the process (Gupta and Leong, 2007).…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Kinetic study of multiphase reactions under microwave irradiation: A mini-review

Adavi

Amini²,

Latifi³

et al. 2022

Front. Chem. Eng.

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Microwave (MW) heating is rapid, selective, and volumetric, and it is a compelling non-conventional heating approach for driving chemical reactions. The effect of MW irradiation on the kinetics of thermal/catalytic reactions is still under debate. A group of researchers reported that the effect of MW heating on reaction kinetics is highlighted through the non-thermal effects of MWs on kinetic parameters and reaction mechanisms in addition to the thermal effect. However, another group attributed the observations to the thermal effect only. In the present work, we summarized and critically synthesized available information in the literature on the subject. It can be concluded that MW heating has solely the thermal effect on gas-solid reactions, and the variations of kinetic parameters are related to the direct and indirect impacts of that. Temperature measurement limitations, physical structure variation, and non-uniform temperature distribution are the primary sources of the discrepancy in previous studies. In ionic liquid-solid reactions, the presence of electromagnetic fields can affect the movement of ions/polar molecules which can be considered a non-thermal effect of MWs. However, the effect of MW absorption by solid/catalyst, and the formation of hot spots must be taken into account to avoid potential discrepancy. Therefore, further theoretical/experimental studies are required to clarify the effect of MWs on liquid-solid reactions. In addition, developing reliable temperature measurement methods and isothermal reaction domain are required for an accurate kinetic study during MW irradiation.

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Section: Kinetics Of Gas/liquid-solid Reactionsmentioning

confidence: 99%

Section: Kinetics Of Gas/liquid-solid Reactionsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Kinetic study of multiphase reactions under microwave irradiation: A mini-review

Adavi

Amini²,

Latifi³

et al. 2022

Front. Chem. Eng.

Self Cite

View full text Add to dashboard Cite

show abstract

“…In recent years, MW heating has attracted intense attention owing to its advantages of overall, volumetric, instantaneous, and selective heating, high energy efficiency, cleanliness, and safety [19][20][21][22][23]. Especially in the fields of chemistry and chemical industry, MW heating is attractive due to its unique ability to promote mass transfer [24][25][26] and/or accelerate reaction kinetics [27][28][29][30][31][32]. Solid-state processing at high temperatures, such as MW synthesis of carbides, is probably the most enormous potential area for energy savings from MW processing.…”

Section: Introductionmentioning

confidence: 99%

Experimental Investigation on the Mass Diffusion Behaviors of Calcium Oxide and Carbon in the Solid-State Synthesis of Calcium Carbide by Microwave Heating

Chen

Dai

et al. 2021

Molecules

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Microwave (MW) heating was proven to efficiently solid-synthesize calcium carbide at 1750 °C, which was about 400 °C lower than electric heating. This study focused on the investigation of the diffusion behaviors of graphite and calcium oxide during the solid-state synthesis of calcium carbide by microwave heating and compared them with these heated by the conventional method. The phase compositions and morphologies of CaO and C pellets before and after heating were carefully characterized by inductively coupled plasma spectrograph (ICP), thermo gravimetric (TG) analyses, X-ray diffraction (XRD), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). The experimental results showed that in both thermal fields, Ca and C inter-diffused at a lower temperature, but at a higher temperature, the formed calcium carbide crystals would have a negative effect on Ca diffusion to carbon. The significant enhancement of MW heating on carbon diffusion, thus on the more efficient synthesis of calcium carbide, manifested that MW heating would be a promising way for calcium carbide production, and that a sufficient enough carbon material, instead of CaO, was beneficial for calcium carbide formation in MW reactors.

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Kinetics of microwave carbothermal reduction of Sb₂O₃: Isothermal and non‐isothermal microwave thermogravimetric analysis

Yang,

Liu,

Zhu

et al. 2024

Asia-Pacific J Chem Eng

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Kinetics of antimony production via carbothermal reduction of Sb2O3–carbon powder–NaCl mixture using microwave and conventional heating was investigated to identify the dominant controlling mechanism. Results of conventional heating revealed the temperature range of conventional carbothermal reduction reaction is 500°C to 800°C, with the average activation energy of each stage being 81.97 kJ/mol (α = 0.1–0.5), 65.17 kJ/mol (α = 0.5–0.75), and 69.86 kJ/mol (α = 0.75–1.0), respectively. In the microwave field, the carbothermal reduction reaction of raw materials can be completed at 600°C to obtain antimony, and the weight loss data of the carbothermal reduction process were recorded for the first time. The above results show that the microwave field enhanced the interfacial chemical effect, accelerated the interfacial diffusion from the metal phase to the oxide phase, and reduced the activation energy of the carbon thermal reduction process to 6.85 kJ/mol. The growth index of antimony grain growth process is estimated to be 4.33, controlled by the surface diffusion. These data provide a reliable theoretical basis for studying the reduction reactions of minerals in microwave fields.

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A kinetic comparison between microwave heating and conventional heating of FeS-CaO mixture during hydrogen-reduction

Cited by 27 publications

References 34 publications

Kinetic study of multiphase reactions under microwave irradiation: A mini-review

Kinetic study of multiphase reactions under microwave irradiation: A mini-review

Experimental Investigation on the Mass Diffusion Behaviors of Calcium Oxide and Carbon in the Solid-State Synthesis of Calcium Carbide by Microwave Heating

Kinetics of microwave carbothermal reduction of Sb₂O₃: Isothermal and non‐isothermal microwave thermogravimetric analysis

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A kinetic comparison between microwave heating and conventional heating of FeS-CaO mixture during hydrogen-reduction

Cited by 27 publications

References 34 publications

Kinetic study of multiphase reactions under microwave irradiation: A mini-review

Kinetic study of multiphase reactions under microwave irradiation: A mini-review

Experimental Investigation on the Mass Diffusion Behaviors of Calcium Oxide and Carbon in the Solid-State Synthesis of Calcium Carbide by Microwave Heating

Kinetics of microwave carbothermal reduction of Sb2O3: Isothermal and non‐isothermal microwave thermogravimetric analysis

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Kinetics of microwave carbothermal reduction of Sb₂O₃: Isothermal and non‐isothermal microwave thermogravimetric analysis