CAD of Efficient TM mnoSingle-ModeElliptical Applicators with Coaxial Excitation

Комаров, В. Н.; Yakovlev, Vadim V.

doi:10.1080/08327823.2005.11688539

Cited by 6 publications

(10 citation statements)

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“…The magnetite catalyst was heated by MWs in an aluminium elliptical applicator equipped with a quarter-wavelength dipole antenna at one focal point of the ellipsoid (Chronix, Inc.). A TM 110 single mode was formed in the elliptical applicator 33 equipped with a semiconductor microwave generator (2.45 GHz). The quartz reactor was then placed at the other focal point.…”

Section: Methodsmentioning

confidence: 99%

Enhancement of Fixed-bed Flow Reactions under Microwave Irradiation by Local Heating at the Vicinal Contact Points of Catalyst Particles

Haneishi

Tsubaki

Abe

et al. 2019

Sci Rep

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The formation of local high temperature regions, or so-called “hot spots”, in heterogeneous reaction systems has been suggested as a critical factor in the enhancement of chemical reactions using microwave heating. In this paper, we report the generation of local high temperature regions between catalyst particles under microwave heating. First, we demonstrated that reaction rate of the dehydrogenation of 2-propanol over a magnetite catalyst was enhanced 17- (250 °C) to 38- (200 °C) fold when heated with microwave irradiation rather than an electrical furnace. Subsequently, the existence of microwave-generated specific local heating was demonstrated using a coupled simulation of the electromagnetic fields and heat transfer as well as in situ emission spectroscopy. Specific high-temperature regions were generated at the vicinal contact points of the catalyst particles due to the concentrated microwave electric field. We also directly observed local high temperature regions at the contact points of the particles during microwave heating of a model silicon carbide spherical material using in situ emission spectroscopy. We conclude that the generation of local heating at the contact points between the catalyst particles is a key factor for enhancing fixed-bed flow reactions under microwave irradiation.

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Section: Methodsmentioning

confidence: 99%

Enhancement of Fixed-bed Flow Reactions under Microwave Irradiation by Local Heating at the Vicinal Contact Points of Catalyst Particles

Haneishi

Tsubaki

Abe

et al. 2019

Sci Rep

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show abstract

“…MW was conducted with an elliptical applicator equipped with a quarter-wavelength dipole antenna at one focal point of the ellipsoid. The TM 110 single mode formed in the elliptical applicator . A quartz reactor was placed at the other focal point.…”

Section: Experimental Methodsmentioning

confidence: 99%

“…The TM 110 single mode formed in the elliptical applicator. 20 A quartz reactor was placed at the other focal point. The elliptical applicator was equipped with a semiconductor generator at a frequency of 2.45 GHz (Chronix, Inc.; Figure 1a).…”

Section: Experimental Methodsmentioning

confidence: 99%

Electromagnetic and Heat-Transfer Simulation of the Catalytic Dehydrogenation of Ethylbenzene under Microwave Irradiation

Haneishi

Tsubaki

Maitani

et al. 2017

Ind. Eng. Chem. Res.

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Electromagnetic and heat-transfer simulations were used to study the effects of microwave-generated nonuniform temperature distributions in a catalyst bed on the rate enhancement of a fixed-bed flow reaction. We used the dehydrogenation of ethylbenzene over a magnetite catalyst as a model reaction. During the microwave reaction, a temperature gradient was generated in the catalyst bed; the highest temperature occurred at the core of the catalyst bed, and it parabolically decreased toward the surface. Using these simulation results and Arrhenius parameters, the reaction rates were estimated by considering the nonuniform temperature distribution. The measured reaction rate was 36% larger than the simulated value, indicating that the rate enhancement under microwaves can not only be attributed to the nonuniform temperature distribution in the catalyst bed. This could be due to nonequilibrium local heating (the so-called hot spot) in the very small region around the catalyst particle.

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“…17 Loaded cavity analysis is considerably more complex making general-purpose numerical techniques essential for practical design. 15 The succession of modes in an elliptical waveguide is a function of its eccentricity. 18 The first four TM modes and the electric field distribution in an elliptical cavity with eccentricity 0.7 are shown in Figure 2, calculated using eigenmode analysis in CST Microwave.…”

Section: Initial Cavity Dimensioningmentioning

confidence: 99%

“…This geometry prevents the formation of degenerated low order modes, mode splitting or polarization rotation due to deformation. 5,[13][14][15] A design methodology for a high-electric field system is proposed, tested, and validated experimentally.…”

Section: Introductionmentioning

confidence: 99%

S‐band elliptical–cylindrical cavity resonator for material processing

Rodríguez

Ampuero

Valderrama

et al. 2022

Micro & Optical Tech Letters

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The development of an elliptical-cylindrical cavity for microwave thermal processing of materials at high electric field strengths is reported. The design methodology based on numerical modeling is validated by experimental measurements. The system can create high-power densities in the heated phases, excellent treatment uniformity, and stable operation without degenerated modes or polarization rotation as suffered by other commonly used circular resonator cavities.

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CAD of Efficient TM mnoSingle-ModeElliptical Applicators with Coaxial Excitation

Cited by 6 publications

References 0 publications

Enhancement of Fixed-bed Flow Reactions under Microwave Irradiation by Local Heating at the Vicinal Contact Points of Catalyst Particles

Enhancement of Fixed-bed Flow Reactions under Microwave Irradiation by Local Heating at the Vicinal Contact Points of Catalyst Particles

Electromagnetic and Heat-Transfer Simulation of the Catalytic Dehydrogenation of Ethylbenzene under Microwave Irradiation

S‐band elliptical–cylindrical cavity resonator for material processing

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