Single heating rate methods are a faulty approach to pyrolysis kinetics

A New Technique for Calculating Kinetic and Thermodynamic Barriers for Nucleation Rates and Interfacial Energy of CaCO3 Prenucleation Nanoclusters at High Temperature Using TGA Models and In Situ Crystallization

“…Furthermore, it was observed that ΔH vs 𝛼 plots at different heating rates coincided to each other, indicating its heating rate independent behavior. Similarly, other thermodynamic parameters like ΔG and ΔS were also found independent of three heating rates (10,15, and 20 °C min −1 ), despite their dependency on peak temperature of different heating rates. It is observed that (Figure 5b) during initial reaction progression, ΔH increases till 𝛼 = 0.2 conversion and then falls, giving sinusoidal pattern, which is repeated for the next conversion values.…”

“…[ 63 ] Different studies have suggested a tenfold variation in the nucleation rates due to assumption of constant $${J}_o$$ values at normal temperature points. [ 12–64 ] Consequently, computation of $${J}_o$$ was performed by determining $${A}_{\alpha}\ \mathrm{and}\ {E}_{\alpha}$$, using experimentally generated TGA data. A precise value of apparent activation energy $$( {{E}_\alpha } )$$ of nucleation for CCPN matrix is computed by iterative procedure (Equation (16)) and provided in Table 2 and Table S2 (Supporting Information).…”

“…[9] Moreover, Many preceding studies suggest that the nucleation rate increases exponentially as function of temperature, [65] especially in the low (20-35°C) and high temperature (580-680 °C) ranges. [66] Further, nucleation rates were also computed at different heating rates (10,15, and 20 °C min −1 ), it was observed that the nucleation rate increases, upon increment in heating rate (Figure 6a). This is due to the fact that heat and mass resistance are substantially decreased at higher temperature, leading higher nucleation rates.…”

“…By doing multiple experimental runs, the accuracy in the reaction kinetics (i.e., activation energy) get enhanced when compared to single heating rate methods such as Coats–Redfern (CR [ 14 ] ) and Distributed Activation Energy Model (DAEM [ 14 ] ) models. [ 15 ] Moreover, isoconversional approach not assumes any particular reaction model like CR and DAEM models, led to generation of unique kinetic parameters at specific conversion. [ 16 ] Thereby, isoconversional methods are typically more accurate than single heating rate methods.…”