A practical method to derive sample temperature during nonisothermal coupled thermogravimetry analysis and differential scanning calorimetry experiments
Résumé
Nonisothermal thermogravimetry differential scanning calorimetry (TG-DSC) mounting is intensively used for the determination of kinetic parameters and reaction heat along the chemical transformation of a solid. Nevertheless, when tests are performed with heating rates as high as those encountered in industrial processes, e.g., several tens of K min-1 , there is great uncertainty in the knowledge of the exact sample temperature. In this work, a method to derive a simple mathematical expression is proposed and fully described in order to calculate the real sample temperature throughout a temperature-ramped test on a commercial apparatus. The furnace temperature and the heat flow signals were used, together with the crucible specific heat and the heating rate. A number of validation tests were performed to derive similar reaction rates for a reference. First-order kinetic reactions were presented and reconciled over a large range of heating rates from 3 to 50 K min-1 .
Domaines
Sciences de l'ingénieur [physics]
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