A new, improved method to identify reaction mechanisms based on the shape of derivative thermogravimetric curves

Abstract

This study firstly presents a summary of using differential thermogravimetric (DTG) data for identifying reaction mechanisms of solid-state reactions. It shows that applying features delineated in currently-used models for initial and final temperatures are problematic during the classification of reaction mechanisms. Secondly, it develops a relationship linking the number of distinct peaks in second derivative thermogravimetric (DDTG) curves for selecting reaction mechanisms. An analysis is also given discussing the maximum conversion rates and relevant values of half widths in DTG curves, and recommends modified limits of these parameters which cover a greater majority of solid-state reactions. Based on the revised parameters, a new flow chart is developed to define reaction mechanisms. This flow chart is applied to the experimental combustion of three different of coal samples for which data analyses proved to be simple and reliable, and then from which distinct reaction mechanisms were determined successfully.

Keywords

• Thermogravimetry
• Reaction mechanism
• Non-isothermal kinetics
• Thermal analysis