Res. Agr. Eng., 2014, 60(10):S52-S56 | DOI: 10.17221/35/2013-RAE

Sorption isotherms of agricultural productsOriginal Paper

I. Vitázek, J. Havelka
Department of Transport and Handling, Faculty of Engineering, Slovak University of Agriculture in Nitra, Nitra, Slovak Republic

The aim of the paper is to expand the theory of sorption and equilibrium moisture contents as well as to present the methodology of developing two types of sorption isotherms - I and II. The attention is also paid to the importance of the isotherms in the thermodynamics of drying and in the process of storage of agricultural products. Presented methodology of obtaining the isotherms is based on selected equations of the theory of adsorption and on the results of experimental measurements of equilibrium moisture content. Definition of the new isotherm II is introduced as dependence of equilibrium moisture content dry basis on time at constant temperature, constant relative moisture of the ambient air and stable biological properties (e.g. germination). The results show following graphic dependences: isothermal distort plane; sorption isotherm I of maize grains at various temperatures; moisture loss rate in dependence on time and sorption isotherm II. These theoretical dependences supported by experimental measurements broaden the scope of the theory of sorption and may be successfully applied in long-term storage of maize grains.

Keywords: equilibrium moisture; drying; thermodynamics; organic materials; drying curve

Published: December 31, 2014  Show citation

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Vitázek I, Havelka J. Sorption isotherms of agricultural products. Res. Agr. Eng. 2014;60(Special Issue):S52-56. doi: 10.17221/35/2013-RAE.
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