WATER - CORN EQUILIBRIUM: TEMPERATURE DEPENDENCY OF THE G.A.B. MODEL PARAMETERS AND CALCULATION OF THE HEAT OF SORPTION
Titel:
WATER - CORN EQUILIBRIUM: TEMPERATURE DEPENDENCY OF THE G.A.B. MODEL PARAMETERS AND CALCULATION OF THE HEAT OF SORPTION
Auteur:
Gely, Maria Cristina Giner, Sergio A.
Verschenen in:
Drying technology
Paginering:
Jaargang 18 (2000) nr. 7 pagina's 1449-1464
Jaar:
2000-08-01
Inhoud:
By using sorption data for com in the range of 4.4-60°C, the temperature (T) variations of the GAB. model parameters (Mm, CB and k) were studied. As only the monolayer moisture (Mm) varied (decreased) with temperature, a generalized GAB equation of four total parameters was obtained. This, together with the Clapeyron equation allowed a method to calculate the heat of sorption (Lb) as a function of T and moisture content (M). For each temperature, Lb presented a maxinuin some 30% above the heat of vaporization of water (Lf), which occurred around the Mm, in congruence with the sorption theory. A similar behavior of Lb was found using the Othmer method. In contrast, the Gallaher equation predicted an ever increasing Lb up to 3 Lf at very low moistures. The GAB-Clapeyron method is then proposed to calculate Lb as a function of M and T.
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