On the nonlinear isoconversional procedures to evaluate the activation energy of nonisothermal reactions in solids

Abstract

A general procedure for deriving the equations that underlie various isoconversional nonlinear methods for evaluating the activation energy is presented. A new integral isoconversional nonlinear method with integration over a given range of conversion is suggested. This method was applied to simulated nonisothermal data as well as to data for the nonisothermal decomposition of ammonium perchlorate. The obtained dependencies of the activation energy on the degree of conversion were compared with those resulting from other nonlinear and linear methods of analysis. C 2003 Wiley Periodicals, Inc. Int J Chem

Evaluation of the Pyrolysis and Gasification Kinetics of Tropical Wood Biomass

“…In iso-conversional methods, it is assumed that the reaction model ( ) in the rate Equation 1 is not dependent on either the temperature or heating rate (Vyazovkin and Wight 1999). In these methods, apparent activation energy can be calculated without any knowledge of the reaction model ( ) (Budrugeac and Segal 2004).…”

An iterative model-free method to determine the activation energy of heterogeneous processes under arbitrary temperature programs

“…The linear differential method suggested by Friedman [18] (FR method) and nonlinear differential method suggested by Budrugeac [19] (NL-DIF method) can be applied to handle data obtained under arbitrary variation of temperature. However, these methods involve the evaluation of the local reaction rates, which are sensitive to inherent noises and tend to be numerically unstable [20].…”

Thermal Characterization and Model Free Kinetic Application on a Tar Sand Sample

“…The results showed that when the activation energy was dependent on the degree of conversion, the E values rely on the lower limit of the integration. By using this method, the range of conversion degree can be found out for a ratedetermining step (Budrugeac and Segal, 2004). Both model-free (isoconversional) and model-fitting methods were applied to the thermal degradation of polymers.…”