A Practical Method to Derive Sample Temperature during Nonisothermal Coupled Thermogravimetry Analysis and Differential Scanning Calorimetry Experiments

• Published in: Chemical engineering & technology 2006-06, Vol.29 (6), p.696-702
• Main Authors: Salvador, S., Ferrasse, J.-H.
• Format: Article
• Language: English
• Subjects: Applied sciences; Calorimeters; Chemical engineering; Engineering Sciences; Exact sciences and technology; Heat and mass transfer. Packings, plates; Kinetics
• ISSN: 0930-7516; 1521-4125
• DOI: 10.1002/ceat.200600022

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. A practical method is proposed for establishing a simple mathematical expression dedicated to the thermogravimetry differential scanning calorimetry (TG‐DSC) apparatus used, to calculate throughout an experiment the temperature difference between the sample and the furnace.