Combustion Characteristics and Decomposition Kinetics of Melon Seed Husks Based on the Distributed Activated Energy Model

Abstract

This paper examined the thermal decomposition kinetics of melon seed husks (MSH) under multi-heating rates and non-isothermal oxidative conditions by thermogravimetric analysis (TGA), tem-perature profile characteristics (TPCs), and the distributed activated energy model (DAEM). The thermal analysis resulted in 95.06 – 95.77% mass loss (ML) and 4.01 – 4.94% residual mass (RM). The TPCs indicated that the midpoint (Tmid), endpoint (Tend), peak drying and peak devolatilization temperatures (I and II) increased with incremental heating rates except for the ignition (Tons). In addition, the changes in temperature and heating rates significantly influenced the thermal behaviour, degradation mechanisms, and TPCs as evident in TG/DTG plots. Kinetic analyses indicated the activation energy (Ea) and frequency factor (A) also fluctuated significantly during TGA. The values of Ea were from 46.53 kJ/mol to 533.82 kJ/mol, whereas A was from 3.62 min-1 to 1.68 × 1051 min-1 with average values of 215.56 kJ mol-1 and 8.85 × 1049 min-1, respectively. Overall, the MSH displayed high thermal reactivity during thermal and kinetic analyses. Hence, combustion is a potentially practical route for the valorisation of MSH into clean energy for a sustainable environment.