Experimental and mathematical investigation of parameters drying of leather by hot air

The determination of leather drying characteristics is of a fundamental importance to give an optimization of the drying step. As it is the target of this paper to depict an experimental way to determine the kinetics of leather drying, an experimental study was carried out on a laboratory-scale dryer under various conditions of air humidity, temperature and air velocity in order to optimize the drying circumstances. Leather samples were dried in convection dryer, the drying kinetics were experimentally investigated at 40, 45, 50, 55 and 60 °C and performed at three values of relative humidity 15, 30 and 45% and three air velocities 1, 1.5 and 2 m/s. To compare drying kinetics, experimentally obtained data, X = f (t), were correlated by fitting the selected five mathematical models that were tested to fit the drying curves, the Modified Page model appeared the most suited to characterize experimental data. High levels of correlation between measured data and those of modeled data were achieved for leather and dryers, employing Modified Page model. The drying process of leather presented a combination of the short warm-up period, the first falling rate period and the second falling rate period.