The physico-geometric kinetics for the solid-state reactions by thermoanalytical (TA) measurements were reexamined by focusing
some fundamental aspects: (1) the fundamental kinetic equation, (2) the kinetic model function, (3) the fractional reaction
α, and (4) the apparent kinetic parameters. It was pointed out that some pitfalls in the practical kinetic study are originated
by the disagreement between the kinetic information from the TA measurements and the theory of the physico-geometric kinetics.
In order to increase the degree of coordination between the theory and practice, several attempts were made from both the
theoretical and experimental points of views. The significance of the apparent kinetic parameters was discussed with a possible
orientation for obtaining the reliable kinetic parameters.
Effects of sample mass on the kinetics of isothermal dehydration of crushed crystals of Li2SO4·H2O were investigated using conventional TG. The process was characterized by a combination of Avrami-Erofeyev and contracting
geometry models. Distribution of the fractional reaction, α, in particles within the sample assembly as well as the change
in the rate of gross diffusion of the evolved water vapour appear responsible for the sample-mass-dependent kinetic parameters
obtained for the system.
Authors:S. Xiu, H. K. Rojanala, A. Shahbazi, E. H. Fini, and L. Wang
dependent on temperature [ 16 ].
The solid combustion reaction rates are generally expressed as:
where the fractionalreaction α is defined in the terms of the change in mass of the bio-oil sample:
where m 0 , m , and m f are the
Authors:S. K. Mehta, Ravneet Kaur, and Sukhjinder Singh
where α is the fractionalreaction; t , is time; A is the pre-exponential factor; E is the activation energy; R is the gas constant; T is temperature in Kelvin, and f (α) is the kinetic function, which takes different forms
Authors:Juliusz Leszczynski, Krzysztof T. Wojciechowski, and Andrzej Leslaw Malecki
divided by k − σ/k , and a sum of squared error SSE between measured and estimated fractionalreaction (α exp − α calc ) 2 . Due to a deceleratory type of the oxidation curves, mainly deceleratory kinetic models for the solid-state reactions were
Authors:J. Selvakumar, D. Sathiyamoorthy, and K. S. Nagaraja
-isothermal experiments. These experiments usually involve measurements of mass or heat evolved, etc., which can be related directly to the fractionalreaction α, at a series of different, usually constant, heating rates ( β = d T /d t ) [ 13 ]. The direct estimation of
(fractionalreaction) α–time curve, typical of many solid-state decompositions [ 5 – 7 ], is identified as resulting from energy transfer, a characteristic feature of the active reactant–product interface. During the induction period, S int is zero (no