Temperature Measurement Methods in Microwave Heating Technologies

Lapshinov, B. A.

doi:10.1007/s11018-021-01954-w

Cited by 15 publications

(6 citation statements)

References 17 publications

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“…Pyrometry is the most widely used noncontact technique for measuring temperature in the presence of electromagnetic irradiation. This method involves measuring the surface temperature of a heated target through the detection of thermal radiation in the near-infrared wavelength range . A comparison of temperature measurement techniques for microwave systems is provided elsewhere. , …”

Section: Materials and Methodsmentioning

confidence: 99%

“…This method involves measuring the surface temperature of a heated target through the detection of thermal radiation in the near-infrared wavelength range. 27 A comparison of temperature measurement techniques for microwave systems is provided elsewhere. 28,29 In this study, the sample bulk temperature was controlled and measured automatically by an incorporated IR temperature sensor within the instrument microwave cavity with a 0.1 °C precision.…”

Section: Washing and Separationmentioning

confidence: 99%

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Microwave-Assisted Nickel and Vanadium Removal from Crude Petroleum Oil Using Bis(2-ethylhexyl)phosphoric Acid: A Kinetic Study

Solouki

Monzavi

Chaouki

2023

Ind. Eng. Chem. Res.

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Among the various metals in crude oils, nickel (Ni) and vanadium (V) exist as oil-soluble organic compounds, making them extremely difficult to remove. The presence of these metals has been proven to have deleterious effects, such as catalyst poisoning and corrosion in crude refinery processes. This study aimed for Ni/V removal from Iranian crude oil using bis(2ethylhexyl)phosphoric acid (D2EHPA) under microwave heating. The impact of primary process parameters, such as temperature, residence time, and D2EHPA dosage, on Ni and V removal efficiencies was studied. The demetallization reaction kinetics and mechanism were investigated at 230−250 °C and optimized conditions. The findings demonstrated that at low microwave powers of 40−50 W, Ni and V removal efficiencies could reach up to 63% and 72%, respectively, after a reaction time of 1 h at 250 °C. The kinetics of demetallization reactions was found to be of first-order, and the activation energies and pre-exponential factors for Ni and V were estimated to be 29.8 and 34.7 kJ/mol and 16.5 and 66.2 min −1 , respectively. A well-fitted kinetic model was proposed based on the coefficients of determination. The reaction between the metalloporphyrins in crude oil and D2EHPA resulted in the substitution of Ni and V with protons provided by D2EHPA, leading to the formation of metal salts that are soluble in water. The formation of N−H bonds in the treated oil, as confirmed by the FTIR analysis results, indicated the occurrence of the demetallization reaction.

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Section: Materials and Methodsmentioning

confidence: 99%

Section: Washing and Separationmentioning

confidence: 99%

Microwave-Assisted Nickel and Vanadium Removal from Crude Petroleum Oil Using Bis(2-ethylhexyl)phosphoric Acid: A Kinetic Study

Solouki

Monzavi

Chaouki

2023

Ind. Eng. Chem. Res.

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“…Pyrometers do not require complex optical and scanning equipment, which reduces investment costs. In research and industrial applications, pyrometers are widely established in microwave applications, especially in fields that go beyond food use and that, therefore, provide additional information on calibration (Croquesel et al, 2021;Ghorbel et al, 2021;Lapshinov, 2021) and plant setup, such as realization of microwavesafe optical windows for pyrometers (Catala-Civera et al, 2015;García-Baños et al, 2019).…”

Section: Pyrometermentioning

confidence: 99%

Critical assessment of methods for measurement of temperature profiles and heat load history in microwave heating processes—A review

Kalinke

Kubbutat

Dinani

et al. 2022

Comp Rev Food Sci Food Safe

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Limitations of microwave processing due to inhomogeneities of power input and energy absorption have been widely described. Over‐ and underheated product areas influence reproducibility, product quality, and possibly safety. Although a broad range of methods is available for temperature measurement and evaluation of time/temperature effects, none of them is sufficiently able to detect temperature differences and thermally induced effects within the product caused by inhomogeneous heating. The purpose of this review is to critically assess different methods of temperature measurement for their suitability for different microwave applications, namely metallic temperature sensors, thermal imaging, pyrometer measurement, fiber optic sensors, microwave radiometry, magnetic resonance imaging, liquid crystal thermography, thermal paper, and biological and chemical time‐temperature indicators. These methods are evaluated according to their advantages and limitations, method characteristics, and potential interference with the electric field. Special attention is given to spatial resolution, accuracy, handling, and purpose of measurement, that is, development work or online production control. Differences of methods and examples of practical application and failure in microwave‐assisted food processing are discussed with a special focus on microwave pasteurization and microwave‐assisted drying. Based on this assessment, it is suggested that infrared cameras for measuring temperature distribution at the product surface and partially inside the product in combination with a chemical time/temperature indicator (e.g., Maillard reaction, generating heat‐induced color variations, depending on local energy absorption) appear to be the most appropriate system for future practical application in microwave food process control, microwave system development, and product design. Reliable detection of inhomogeneous heating is a prerequisite to counteracte inhomogeneity by a targeted adjustment of process and product parameters in microwave applications.

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“…Currently, no technique is reported in literature studies to effectively measure the local temperatures of gas and solid phases under MW heating . This limitation has a crucial influence on gas–solid reactive systems, since the temperature of the hotspots on the solid surface is a vital factor to explain the absence or presence of nonthermal effects of MWs. ,, Available techniques for temperature measurements in MW-heated systems are metallic thermocouples, ,− infrared (IR) thermography, , pyrometers, , fiber optic probes, , air thermometers, radiometry method, , polymeric thermometers, wireless thermocouples, and Raman spectroscopy. , …”

Section: Introductionmentioning

confidence: 99%

Temperature Distribution Assessment in Gas–Solid Reactive and Nonreactive Systems Heated by Microwaves

Adavi

Shabanian

Chaouki

2023

Ind. Eng. Chem. Res.

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Research studies have shown that selective heating of different phases in gas−solid systems exposed to microwave (MW) irradiation leads to a temperature gradient between gas and MW absorber solids. This can suppress undesired secondary gas-phase reactions and yield apparent kinetic improvements and energy savings. However, the effects of reaction exothermicity/ endothermicity, gas velocity, temperature probe location at the microscale, and MW penetration depth in fixed beds on the temperature difference between solid and gas phases exposed to MWs and temperature distribution in the fixed beds are poorly understood. Highlighting these effects was targeted in this study and accomplished with the help of multiphysics simulations by COMSOL Multiphysics (5.6). The corresponding COMSOL model was initially verified and validated by data collected from literature studies and those obtained experimentally by the authors in this study. Simulation results from the verified and validated model indicated that the temperature gradient between the gas and the MW absorber solid increases by increasing the gas velocity or switching from an endothermic reaction to no reaction and/or an exothermic reaction. In addition, the collected results show nonuniform temperature distribution in a fixed-bed reactor made of MW absorber particles irradiated by MWs due to the limited penetration depth of MWs and hotspot formation. This operational deficiency makes the large-scale design of this type of reactor very challenging for MW heating-assisted reactions.

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Temperature Measurement Methods in Microwave Heating Technologies

Cited by 15 publications

References 17 publications

Microwave-Assisted Nickel and Vanadium Removal from Crude Petroleum Oil Using Bis(2-ethylhexyl)phosphoric Acid: A Kinetic Study

Microwave-Assisted Nickel and Vanadium Removal from Crude Petroleum Oil Using Bis(2-ethylhexyl)phosphoric Acid: A Kinetic Study

Critical assessment of methods for measurement of temperature profiles and heat load history in microwave heating processes—A review

Temperature Distribution Assessment in Gas–Solid Reactive and Nonreactive Systems Heated by Microwaves

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