Modeling and Simulation of Deep-Bed Grain Dryers

Sitompul, Johnner P.; Istadi, Istadi; Widiasa, I Nyoman

doi:10.1081/drt-100102903

Cited by 47 publications

(26 citation statements)

References 7 publications

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“…Moreover, the effect of air velocity distribution (pressure field) on the drying process was studied. Basically the same model (Sitompul et al, 2003) was used for a different dryer geometry (large diameter column). Special attention on the interfacial conditions was placed by Herman et al (2001).…”

Section: Introductionmentioning

confidence: 99%

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Numerical study on hygroscopic material drying in packed bed

Stakić

Banjac

Urošević

2011

Braz. J. Chem. Eng.

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-The paper addresses numerical simulation for the case of convective drying of hygroscopic material in a packed bed, analyzing agreement between the simulated and the corresponding experimental results. In the simulation model of unsteady simultaneous one-dimensional heat and mass transfer between gas phase and dried material, it is assumed that the gas-solid interface is at thermodynamic equilibrium, while the drying rate of the specific product is calculated by applying the concept of a "drying coefficient". Model validation was done on the basis of the experimental data obtained with potato cubes. The obtained drying kinetics, both experimental and numerical, show that higher gas (drying agent) velocities (flow-rates), as well as lower equivalent grain diameters, induce faster drying. This effect is more pronounced for deeper beds, because of the larger amount of wet material to be dried using the same drying agent capacity.

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Section: Introductionmentioning

confidence: 99%

“…Recent models by Sitompul et al (2001) and Istadi and Sitompul (2002) take into account transport phenomena within the deep-bed and in the spherical grains. Moreover, the effect of air velocity distribution (pressure field) on the drying process was studied.…”

Section: Introductionmentioning

confidence: 99%

Numerical study on hygroscopic material drying in packed bed

Stakić

Banjac

Urošević

2011

Braz. J. Chem. Eng.

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“…In order to address this complexity, it is necessary to model the process adequately. A number of drying models have been proposed, which can be classified into empirical [16,17] and mechanistic models [18,19] . It is important to consider a time-varying boundary conditions model if a particular surface temperature is to be considered.…”

Section: Introductionmentioning

confidence: 99%

Management of Surface Drying Temperature to Increase Antioxidant Capacity of Thyme Leaf Extracts (Thymus vulgarisL.)

et al. 2014

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Thyme leaves are an important source of essential oils with antioxidant activity; these compounds are located in trichomes on the leaf surface. The drying conditions affect not only the drying time but also the antioxidant activity. In the literature, a drying temperature of 70 ºC appears to be the best for drying thyme leaves according to their antioxidant capacity. Considering drying periods at different temperature also could be quality beneficial. From these considerations, the goal of this work was to establish a drying strategy with which to manage a drying temperature on the leaf surface which will enable the drying time to be shortened and improve the antioxidant capacity (AC) of the extract of dried thyme leaves. The drying strategy consisted of two consecutive drying periods in order to manage the drying temperature on the leaf surface. The first drying period was carried out at 80°C (T a1 ) until the sample surface reached a temperature of 70 ºC, which then immediately being set to 70, 60, 50 and 40 °C (second drying period (T a2 )), at a different air velocity (v) (1 and 2 m s -1 ). Compared with constant drying conditions, two consecutive drying periods were found to improve the drying kinetics, the AC increased from 10.5% to 27.4 % while reducing the drying time by 14.5% to 39.2 %. The use of this drying strategy was found to be an interesting means of intensifying the convective drying of thyme leaves and its application should be considered when drying similar materials with bioactive compounds on the surface.

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“…Moreover, the effect of air velocity distribution (pressure field) on the drying process was studied. Mainly the same model [19] was used for a different dryer geometry (large diameter column). Boukadida et al [20] developed a 2D model to investigate heat and mass transfer during convective drying of clay brick.…”

mentioning

confidence: 99%

“…They demonstrated the effect of variable porosity and intermittent flux on the drying process. Recent models by Sitompul et al [17] and Istadi and Sitompul [18] developed a 2D-model for spherical grains deep-bed drying taking into account transport phenomena within the bed. Moreover, the effect of air velocity distribution (pressure field) on the drying process was studied.…”

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confidence: 99%

Comparison of 1D and 2D models predicting a packed bed drying

Messai

Ganaoui

Sghaier

et al. 2014

Int. J. Simul. Multidisci. Des. Optim.

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-A numerical study for the modelling of porous particles packed bed drying in one and two dimensions (1D and 2D) is presented in this work. This model is based on the averaging volume approach using two scale changes. Taking into account the non validity of the thermal equilibrium between the gas phase and the porous particle, a two temperatures model is then developed. The numerical resolution of macroscopic equations describing heat and mass transfer during the drying of a packed bed is carried out by the method of finite volume. Experimental data for spherical porous alumina particles reported in the literature were used for the validation of the model. A good agreement was found. The influence of particles thermophysical properties and operating variables is tested. A set of time-space evolution describes the progression of these variables with time, in the height and radius of the packed bed. The model results allow a better understanding of the heat and mass transfer mechanisms involved in a packed bed drying process.

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Modeling and Simulation of Deep-Bed Grain Dryers

Cited by 47 publications

References 7 publications

Numerical study on hygroscopic material drying in packed bed

Numerical study on hygroscopic material drying in packed bed

Management of Surface Drying Temperature to Increase Antioxidant Capacity of Thyme Leaf Extracts (Thymus vulgarisL.)

Comparison of 1D and 2D models predicting a packed bed drying

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