Kinetics of the Clay Roofing Tile Convection Drying

Tomas, Srećko; Skansi, Darko; Sokele, Mladen

doi:10.1080/07373939308916903

Cited by 11 publications

(5 citation statements)

References 2 publications

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“…We found in the literature that volumetric shrinkage of the examined wood samples is as follows: for alder up to 10.1% (Kozlik and Boone, 1987; Rasmussen, 1991) and for willow up to 13.6% (Rasmussen, 1991). Shrinkage of Ilito‐montmorilonite clay was determined by Tomas et al (1993), who found out that clay shrinks up to 6.8%, again mostly during the constant rate period (up to 6%). Vierira et al (2006) concluded that significant changes of the structural properties were verified for the paper dried at 90°C (higher than the end paper temperature dried in the microwave drier).…”

Section: Resultsmentioning

confidence: 98%

Drying of solids; estimation of the mathematical model parameters

2010

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In order to determine physical meaning of a thin-layer mathematical model parameter, the Page model was modified and tested on numerous experimental data. Applicability of the model was tested on the drying kinetics data, X(t), of 11 different types of the porous materials and dried in a convective, vacuum and/or microwave dryers under the predetermined external process conditions. During the entire drying time the drying kinetics of all the investigated materials and heating methods were successfully correlated with the modified Page model. The evaluated values of a new parameter, t k , corresponded to the time at which diffusion, as a governing mechanism of moisture movement through the material, started. The results were confirmed by the pore size distribution of some materials.Afin de déterminer la signification physique d'un paramètre de modèle mathématique des couches minces, le modèle de Page aété modifié et testé en utilisant de nombreuses données expérimentales. L'applicabilité du modèle aété testée en utilisant les données cinétique de séchage, X (t), de onze différents types de matériau poreux et séchés dans des séchoirsà convection, sous vide et/ouà micro-ondes dans des conditions de traitement externes prédéterminées. Pendant toute la durée du séchage, la cinétique de séchage de tous les matériaux et des méthodes thermiqueś etudiées aété corrélée avec succès avec le modèle modifié de Page. Les valeurs estimées d'un nouveau paramètre, tk, ont corresponduà l'heure où la diffusion,étant le mécanisme fondamental contrôlant le mouvement d'humidité au sein du matériau, a débuté. Les résultats ontété confirmés par la distribution des tailles de pores de certains matériaux.

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Section: Resultsmentioning

confidence: 98%

Drying of solids; estimation of the mathematical model parameters

2010

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“…Experimental data on these isotherms at temperature from 20 to 40°C and water activity from 0.20 to 0.70 were determined using the static gravimetric method. The experimental data were fitted by the well-known Guggenheim-Anderson and de Boer (GAB) model (Van den Berg & Bruin, 1981):…”

Section: Desorption Isothermmentioning

confidence: 99%

“…Fick's laws of diffusion and Fourier's law of conduction as well as its derived equation (e.g. Thin-layer drying equation) account for a significant proportion of the mathematical models employed in clay science (Evans and Keey, 1975;Tomas, et al, 1993;Kanno, et al, 1996;Su 1997;Sander, et al, 1998Sander, et al, , 2001Sander, et al, , 2003Moropoulou, et al, 2004Moropoulou, et al, , 2005Murugesan, et al, 2001;Mihoubi, et al, 2004;Dincer and Sahin, 2004;Akpinar and Dincer, 2005;;Chemkhi, et al, 2004Chemkhi, et al, , 2005. However, many of these models include different moisture transfer parameters that have a wide variation of reported values, depending on the complexity of the product and methods of moisture estimation.…”

Section: Introductionmentioning

confidence: 99%

“…There are several models available in the literature to describe the moisture sorption isotherm. They can be divided into several categories: (a) kinetic models based on a mono-layer, such as the BET model (Brunauer et al, 1938), (b) kinetic models based on a multi-layer and condensed film, such as the GAB model (Van den Berg & Bruin, 1981), (c) semiempirical models (Henderson, 1952;Halsey, 1948;Chung and Pfost, 1967) and (d) empirical models (Smith, 1947;Oswin, 1946). However, no model accurately fits sorption isotherm data for different moist products over a broad range of relative humidity and temperature.…”

Section: Introductionmentioning

confidence: 99%

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Moisture Desorption Studies on Polymer Hydrated and Vacuum Extruded Bentonite Clay Mat

Loh

Wijeyesekera

Ciupala

2016

Journal of Heat Transfer

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Moisture desorption observations from two bentonite clay mats subjected to ten 26 environmental zones with individually different combinations of laboratory controlled constant 27 temperatures (between 20⁰C to 40⁰C) and relative humidity (between 15% to 70%) are presented. 28These laboratory observations are compared with predictions from mathematical models, such as 29Thin-layer drying equations and kinetic drying models proposed by Page, Wang and Singh, and 30Henderson and Pabis. The quality of fit of these models is assessed using standard error of 31 estimate, relative percent of error and coefficient of correlation. The Page model was found to 32 better predict the drying kinetics of the bentonite clay mats for the simulated tropical climates. 33Critical study on the drying constant and moisture diffusion coefficient help to assess the efficacy 34 of a polymer to retain moisture and control desorption through water molecule bonding. This is 35 further substantiated with the Guggenheim-Aderson-DeBoer (GAB) desorption isotherm model 36 which is presented. 37 38

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“…Page (1949) and Tomas et al (7) involved the exponent n, as a second parameter (5,7) for better correlation between the experimental data and the mathematical model:…”

Section: Experimental Data Analysismentioning

confidence: 99%

Comparison of Convective, Vacuum, and Microwave Drying Chlorpropamide

2001

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Drying kinetics of convective, vacuum, and microwave drying of a pharmaceutical product, chlorpropamide, has been investigated on a laboratory scale, in the temperature interval from 40 • C to 60 • C, and the range of microwave heating power from 154 W/kg dm to 385 W/kg dm .The experimental data obtained were approximated with the "thin-layer" equation and a two parameter exponential model. In order to compare convective, vacuum, and microwave drying, effective diffusion coefficients and specific heat consumption were calculated for each drying method.Higher rates and shorter drying times were achieved at a higher temperature and microwave heating power. The highest drying rates and the lowest specific heat consumption were achieved with microwave drying. This leads to the conclusion that microwave heating is the most appropriate method for drying of chlorpropamide. The quality of product was not changed for all applied methods.

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Kinetics of the Clay Roofing Tile Convection Drying

Cited by 11 publications

References 2 publications

Drying of solids; estimation of the mathematical model parameters

Drying of solids; estimation of the mathematical model parameters

Moisture Desorption Studies on Polymer Hydrated and Vacuum Extruded Bentonite Clay Mat

Comparison of Convective, Vacuum, and Microwave Drying Chlorpropamide

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