A master plot approach on rice husk decomposition through pyrolysis and kinetic elucidation using iso-conversional models

Abstract

The present study aimed at predicting the intricate mechanism followed by the pyrolysis of locally available rice husk, uses noval modified master plots through continuous slope-based differential techniques. An average apparent activation energy was found in the range of 187.29 (KAS model) and 199.85 kJ mol⁻¹ (OFW model), respectively. The rice husk revealed higher volatile matter; 54.51 wt-%, HHV; 18.42 MJ kg⁻¹and a critical pyrolysis zone around 250 to 550 °C with two sharp peaks through differential thermogravimetric analysis. Using Karl–Pearson correlation, experimental curve showed highest correlation coefficient of 0.94 and 0.75 with respect to A2 and A3 models (Avrami–Erofeev) for g(α). However, for Z(α), the process is limited by first-order multi-diffusion processes (D1) coupled with solid phase surface reaction (F3) showing correlation coefficient of 0.8. The experimental data worked out the generalized model of f(α) as f(α) = 12.74α³ – 24α²+ 12.6α  - 0.92 with R² value of 0.99, narrating the usage of master plots for better understanding of the process.