Activation Energy Determination in Case of Independent Complex Kinetic Processes

Abstract

Theoretically simulated kinetic data were used to evaluate the performance of the most common isoconversional methods of kinetic analysis in complex-process scenarios with two independent overlapping processes exhibiting nucleation-growth kinetics, and further expand the conclusions for the autocatalytic kinetic processes with positive asymmetry. In close-to-real-life situations all the integral isoconversional methods provided practically indistinguishable E-α outcomes. The Friedman and incremental modified Vyazovkin methods results in significant over- and undershoots. However, the combined utilization of the integral and differential isoconversional methods was demonstrated to greatly contribute to the interpretation of the E-α dependences and estimation of E1 and E2—the conceptual evaluation involving positions of inflection points and plateaus is introduced. The influence of the range of applied heating rates q+ on the course of E-α dependences was studied. In this regard, the performance of the isoconversional methods changes significantly with both, the consistence of the shape of the complex kinetic curve and weighted presence of full overlaps of the involved sub-processes.

Kinetic analysis of particle-size based complex kinetic processes

“…2D). In general, the full overlaps of sub-processes with close activation energies are difficult to recognize and interpret via the isoconversional methods [38,56]. This is indeed also the case of the present data, where the kinetic complexity would be uneasy to recognize without the knowledge/comparison with the data for the separated Se powders.…”

“…The isoconversional methods can be further split into two sub-groupsdifferential and integral methods, where each sub-group provides (due to the inherent procedural approach) different E-α dependence. It was recently shown in [38] that in case of…”

Complex process activation energy evaluated by combined utilization of differential and integral isoconversional methods

“…This holds even if the reduced number of evaluated data-curves decreases to 3. When performing the thermo-analytical measurements intended for complex process kinetic calculations, it is therefore recommended to make an initial screening at highest and lowest possible q + , perform measurements at a variety of heating rates [45] but particularly focus on those exhibiting low degrees of overlaps (even if the change of heating rate should be very small).…”

Effect of 5-Amino-1H-Tetrazole on Combustion Pyrolysis Characteristics and Kinetics of a Combustion Tear Gas Mixture

“…In order to further explore the thermal decomposition mechanism of Samples P1-P5 and to calculate the kinetic parameters of each stage of the reaction, Starink's method and the Flynn-Wall-Ozawa method were used [35][36][37]. The TG-DTG curve of Samples P1-P5 at different heating rates is shown in Figure 11.…”