Thermodynamic properties of water desorption in Buchenavia capitata (Vahl) Eichler

• Main Authors: Hellismar W. da Silva, Daniel E. C. de Oliveira, Osvaldo Resende, Lílian M. Costa
• Format: Article
• Language: English
• Published: Universidade Federal de Campina Grande
• Series: Revista Brasileira de Engenharia Agrícola e Ambiental - Agriambi
• Subjects: calor latente; energia livre de Gibbs; relação entalpia-entropia
• Online Access: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662018001200878&lng=en&tlng=en

ABSTRACT Thermodynamic properties provide information on energy demand and kinetic parameters in water sorption processes in agricultural products. Such information is essential to analyze and scale drying and storage equipment. The objective of this study was to determine the thermodynamic properties involved in the water desorption process in Buchenavia capitata (Vahl) Eichler seeds with moisture contents ranging from 13.31 to 7.21% dry basis (d.b.), obtained by the indirect static method, at temperatures of 10, 20, 30 and 40 °C. The latent heat of vaporization, differential entropy and Gibbs free energy increase with the reduction of the moisture content of the seeds. The enthalpy-entropy compensation theory is valid for the desorption process, which is controlled by the enthalpy. The desorption of water in the seeds is not a spontaneous process.