Theoretical and experimental study of heat and mass transfer mechanism during convective drying of multi-layered porous packed bed

Prommas, Ratthasak

doi:10.1016/j.icheatmasstransfer.2011.03.031

Cited by 18 publications

(6 citation statements)

References 21 publications

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“…Additionally, many researchers focus on analyzing the drying processes by using experiment measurements and numerical simulations (Naghavi et al . ; Prommas ; Mabrouk et al . ; Kowalski and Mierzwa ; Torrez Irigoyen et al .…”

Section: Introductionmentioning

confidence: 99%

“…Hawaree et al (2009) in his study evaluated drying temperature and surface characteristics of vegetable on the survival of salmonella to find the influencing factors on the drying. Additionally, many researchers focus on analyzing the drying processes by using experiment measurements and numerical simulations (Naghavi et al 2010;Prommas 2011;Mabrouk et al 2012;Kowalski and Mierzwa 2013;Torrez Irigoyen et al 2014). Xu et al (2014) employed nuclear magnetic resonance and differential scanning calorimetry to access the effect of farinfrared drying on the water state and glass transition temperature of carrots.…”

Section: Introductionmentioning

confidence: 99%

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Optimization of Combined Drying for Lettuce Using Response Surface Methodology

Yuan

Tan

et al. 2015

Journal of Food Processing and Preservation

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In order to obtain the optimized technological parameters of hot air-vacuum combined drying of lettuce, the effects of hot air temperature, intermediate conversion moisture content, slice thickness and vacuum degree (four influence factors) on lettuce drying were explored. The drying time and rehydration ratio of lettuce were the experimental indices, and the relationships between the experimental indices and the influence factors were analyzed by using the response surface methodology. The regression mathematical models were established. The optimized technological parameters of hot air and vacuum combined drying are 50C hot air temperature, 40% intermediate conversion moisture content (w.b.), 20 kPa vacuum degree and 5 mm slice thickness. PRACTICAL APPLICATIONSCombined drying is widely used in food, which is considered as an effective method to achieve energy conservation and shelf life. The objective of this paper was using response surface methodology to obtain optimized hot air vacuum drying parameters for lettuce. The significance of this research can improve the drying efficiency, provide a reference for other fruits and vegetables' drying process optimization and provide a technical basis for the drying of lettuce and the designing of related equipment.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Optimization of Combined Drying for Lettuce Using Response Surface Methodology

Yuan

Tan

et al. 2015

Journal of Food Processing and Preservation

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“…In recent years, many investigators like Mujumdar, Tsotsas, and Zbicinski have devoted their research to drying mathematical model of conjugated transport of moisture content and heat flux through porous medium [4][5][6][7]. Ranjan et al [8] reported a two-dimensional diffusion model describing the heat and mass, momentum transfer to predict the drying rate of bananas.…”

Section: Introductionmentioning

confidence: 99%

Effect of Thermophysical Properties on Coupled Heat and Mass Transfer in Porous Material during Forced Convective Drying

Cai

Zhu

Shi-lin

et al. 2014

Advances in Mechanical Engineering

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The convective drying kinetics of porous medium was investigated numerically. A mathematical model for forced convective drying was established to estimate the evolution of moisture content and temperature inside multilayered porous medium. The set of coupled partial differential equations with the specified boundary and initial conditions were solved numerically using a MATLAB code. An experimental setup of convective drying had been constructed and validated the theoretical model. The temperature and moisture content of the potato samples were dynamically measured and recorded during the drying process. Results indicate that thermal diffusion coefficient has significant positive impact on temperature distribution and mass diffusion coefficient might directly affect the moisture content distribution. Soret effect has a significant impact on heat flux and temperature distribution in the presence of large temperature gradient.

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“…Therefore, all the particles in the dry area are at stable equilibrium states. The temperature of the gas and particles will change only with the height before spontaneous ignition occurs …”

Section: Spontaneous Ignition Theorymentioning

confidence: 99%

Theoretical and Experimental Study on Spontaneous Ignition of Lignite during the Drying Process in a Packed Bed

Gao

Man

et al. 2012

Energy Fuels

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Lignite is a kind of coal which has high moisture content and needs to be dried before being utilized. Lignite has a great spontaneous ignition tendency due to its high volatile content and porous structure. Spontaneous combustion may take place if heat accumulates within the coal layer due to low temperature oxidation, presenting a serious risk during lignite drying. In this paper, a calculation method is developed to predict the spontaneous ignition of lignite during the drying process in a packed bed dryer. The basic principle of this method is that the spontaneous ignition is determined by the combination of convective heat transfer between the gas flow and the particles and the heat generated by the oxidation reactions. The heat generation can be obtained from the differential scanning calorimetry (DSC) curve of the thermogravimetry combustion experiment. The heat loss is obtained by calculating the heat transfer coefficient between the lignite particles and the gas flow. Hence, provided the temperature, the velocity, and the oxygen concentration of the drying gas, together with the size parameters of the particles and the bed, are given, whether the spontaneous ignition occurs or not can be predicted. Moreover, the critical inlet gas temperature, below which the spontaneous ignition will not occur, can be determined as long as the DSC curve is obtained. Numerous experiments have been carried out in a lab-scale reactor. The experimental results were used to verify the calculated results, and the deviations are acceptable.

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Theoretical and experimental study of heat and mass transfer mechanism during convective drying of multi-layered porous packed bed

Cited by 18 publications

References 21 publications

Optimization of Combined Drying for Lettuce Using Response Surface Methodology

Optimization of Combined Drying for Lettuce Using Response Surface Methodology

Effect of Thermophysical Properties on Coupled Heat and Mass Transfer in Porous Material during Forced Convective Drying

Theoretical and Experimental Study on Spontaneous Ignition of Lignite during the Drying Process in a Packed Bed

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