Data/hora: 13/06/2024 08:37:07

Provedor de dados: | 64
País: | Brazil
Título: | Moisture sorption isotherms of sunflower seeds: Thermodynamic analysis
Autores: | Campos,Renata Cássia; Correa,Paulo César; Zaidan,Iasmine Ramos; Zaidan,Úrsula Ramos; Leite,Rildo Araújo.
Data: | 2019-01-01
Ano: | 2019
Palavras-chave: | Hygroscopic equilibrium; Isosteric heat; Enthalpy; Entropy; Gibbs free energy.
Resumo: | ABSTRACT The study of the thermodynamic properties provides the knowledge of the sorbent affinity by the water and the spontaneity of the sorption process, important to design drying equipment and to predict hygroscopic behavior during storage. This work aimed to determine and evaluate isotherms of hygroscopic equilibrium and thermodynamic properties for different equilibrium conditions (water contents and temperatures) in sunflower seeds, using the indirect static method. Sunflower seeds with initial water content of 0.164 (decimal, dry basis - d.b.) were used. Fifteen mathematical models were tested for hygroscopic equilibrium modeling, and the Smith model presented the best fit. It was verified that the thermodynamic properties were influenced by the water content, the integral isosteric desorption heat increased with the decrease of the equilibrium water content, ranging from 1.787 to 2.670 kJ kg-1 to 0.198 to 0.0518 (decimal, d.b.), respectively, the desorption process of the sunflower seeds was controlled by the enthalpy and the Gibbs free energy, which varied from 3.6363 to 200.1730 kJ kg-1, was positive for the temperatures studied, with increase to during the desorption process, proving to be a non-spontaneous process.
Tipo: | Info:eu-repo/semantics/article
Idioma: | Inglês
Identificador: | http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1413-70542019000100227
Editor: | Editora da Universidade Federal de Lavras
Relação: | 10.1590/1413-7054201943011619
Formato: | text/html
Fonte: | Ciência e Agrotecnologia  v.43 2019
Fonte: | info:eu-repo/semantics/openAccess