Semi-industrial continuous band microwave dryer for energy and exergy analyses, mathematical modeling of paddy drying and it's qualitative study

Jafari, Hassan; Kalantari, Davood; Azadbakht, Mohsen

doi:10.1016/j.energy.2017.07.111

Cited by 40 publications

(26 citation statements)

References 46 publications

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“…The figure clearly shows that η ex,DC and SI decrease with the increase of drying time, and respectively range from 14.81% to 40.10% and 1.17 to 1.67. These results are close to those in similar agricultural product industrial dryers, such as an industrial tray dryer for cassava starch drying (16.04% ≤ η ex ≤ 30.65%; 1.19 ≤ SI ≤ 1.44) [ 57 ] and a semi-industrial continuous band microwave dryer for paddy drying (4.13% ≤ η ex ≤ 13.88%; 1.04 ≤ SI ≤ 1.16) [ 49 ]. After six hours, η ex,DC was lower than 20%, indicating that attention should be paid to the optimization of the drying kinetic in this period.…”

Section: Resultssupporting

confidence: 82%

Exergoeconomic Analysis of Corn Drying in a Novel Industrial Drying System

Li¹,

Li²,

Huang³

et al. 2020

Entropy

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The improvement of the design and operation of energy conversion systems is a theme of global concern. As an energy intensive operation, industrial agricultural product drying has also attracted significant attention in recent years. Taking a novel industrial corn drying system with drying capacity of 5.5 t/h as a study case, based on existing exergoeconomic and exergetic analysis methodology, the present work investigated the exergetic and economic performance of the drying system and identified its energy use deficiencies. The results showed that the average drying rate for corn drying in the system is 1.98 gwater/gdry matter h. The average exergy rate for dehydrating the moisture from the corn kernel is 345.22 kW and the exergy efficiency of the drying chamber ranges from 14.81% to 40.10%. The average cost of producing 1 GJ exergy for removing water from wet corn kernels is USD 25.971, while the average cost of removing 1 kg water is USD 0.159. These results might help to further understand the drying process from the exergoeconomic perspective and aid formulation of a scientific index for agricultural product industrial drying. Additionally, the results also indicated that, from an energy perspective, the combustion chamber should be firstly optimized, while the drying chamber should be given priority from the exergoeconomics perspective. The main results would be helpful for further optimizing the drying process from both energetic and economic perspectives and provide new thinking about agricultural product industrial drying from the perspective of exergoeconomics.

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Section: Resultssupporting

confidence: 82%

Exergoeconomic Analysis of Corn Drying in a Novel Industrial Drying System

Li¹,

Li²,

Huang³

et al. 2020

Entropy

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“…SEC in the drying of the walnut kernel in MIC and CON is calculated using Equation (17) (Jafari, Kalantari, & Azadbakht, ; Onwude et al, ).

S E C = \frac{E U_{(m e c + t e r)}}{M_{W}}

…”

Section: Methodsmentioning

confidence: 99%

The effect of microwave and convective dryer with ultrasound pre‐treatment on drying and quality properties of walnut kernel

Abbaspour‐Gilandeh

Kaveh

Jahanbakhshi

2019

J Food Process Preserv

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In this study, the drying kinetics of walnuts was investigated including specific energy consumption (SEC), shrinkage, and walnut kernels' color in two dryers, namely ultrasonic‐convection (US‐CON) and ultrasonic‐microwave (US‐MIC). To carry out this study, walnut samples were dried at three MIC powers (270, 450, and 630 W), three input air temperatures (40, 55, and 70°C) and four duration of ultrasonic pre‐treatment (0 min (control sample), 10, 20, and 40 min). Fifteen mathematical models were used to describe the walnuts' moisture ratio. The results showed that the Midilli et al. model was the best model for describing the process of drying walnuts in US‐CON and US‐MIC dryers. Effective moisture diffusivity (Deff) values were calculated to be between 2.77 × 10–9 and 5.56 × 10–9 m2/s for the US‐CON dryer and 3.12 × 10–9 to 8.99 × 10–9 m2/s for the US‐MIC dryer. The lowest rates of color change were observed in the US‐MIC dryer at the lowest microwave power and the lowest duration of ultrasonic pre‐treatment. The lowest SEC for the US‐CON dryer was 19.52 kWh/kg, and it was 15.90 kWh/kg for the US‐MIC dryer. The highest rate of shrinkage was 14.21%, which was seen in the US‐CON dryer at the air temperature of 70°C and the duration of ultrasonic pre‐treatment of 40 min. According to the results, the best quality of walnut with the lowest changes of color and shrinkage in the microwave dryer was calculated at microwave power 270 W and control sample. Practical applications Drying foods and agricultural products using microwave dryers is a relatively cheap method and has attracted the attention of many researchers today. Also, numerous studies have been conducted on drying agricultural products through microwave and convection dryers with ultrasound pre‐treatment. The result of this study could be applied for gathering comprehensive information regarding the drying process (kinetic, Deff, Ea, and SEC) as well as the qualitative properties (color and shrinkage) of walnut kernels dried using the microwave and convective hot air dryers accompanied by ultrasound pre‐treatment.

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“…From the investigation, it is concluded that by controlling the temperature of the air that reaches the grains, its cracking or bursting is avoided, as a result of the handling of a lower pressure differential in the microwave-assisted system. Finally, other interesting work [17] presents the analysis of energy and exergy, as well as the modeling of a drying system for rice fields, by means of microwaves, carried out on a continuous band of industrial type, recommending the handling of layers of drying of 18mm and powers in the system of 90W.…”

Section: Introductionmentioning

confidence: 99%

Comparative analysis of drying coffee beans using microwave and conventional oven

Muñoz-Neira

Roa-Ardila

Correa-Celi

2019

redin

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This article reports a comparative study of experimental results obtained during the drying of Castilla-variety coffee beans from Santander, Colombia. They were performed by two means: thermal and electromagnetic radiation. Twenty experiments were carried out, ten tests in a microwave cavity at 2,450 MHz-1,080W, and ten tests using a conventional electric oven with temperature controlled at 50±2oC. Experiments were made using samples of coffee beans with parchment, without parchment, and of the only-parchment. For each sample, dimensionless moisture ratio and diffusion coefficients were determined, according to the second law of Fick. We found that the diffusion coefficient of the samples dried in a microwave cavity was twenty-two times higher than the diffusion coefficient of samples dried with thermal radiation. Likewise, it was observed that samples in conventional oven showed a uniform temperature, in contrast with those heated by microwave radiation. Such results are useful for designing hybrid systems for drying coffee beans.

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Semi-industrial continuous band microwave dryer for energy and exergy analyses, mathematical modeling of paddy drying and it's qualitative study

Cited by 40 publications

References 46 publications

Exergoeconomic Analysis of Corn Drying in a Novel Industrial Drying System

Exergoeconomic Analysis of Corn Drying in a Novel Industrial Drying System

The effect of microwave and convective dryer with ultrasound pre‐treatment on drying and quality properties of walnut kernel

Comparative analysis of drying coffee beans using microwave and conventional oven

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