Kinetic and thermodynamic behavior of co-pyrolysis of olive pomace and thermoplastic waste via thermogravimetric analysis

• Published in: Renewable energy 2024-09, Vol.230, p.120880, Article 120880
• Main Authors: Sánchez-Ávila, N., Cardarelli, Alessandro, Carmona-Cabello, Miguel, Dorado, M.P., Pinzi, Sara, Barbanera, Marco
• Format: Article
• Language: English
• Subjects: Agri-food residue; Plastics; Reaction mechanism; Synergistic effect; Valorization
• ISSN: 0960-1481
• DOI: 10.1016/j.renene.2024.120880

This work represents the first attempt to analyze kinetics, thermodynamics and reaction mechanism of olive pomace (OP) and waste plastic materials (PM) co-pyrolysis. Among PM, polypropylene (PP), polystyrene (PS), high density polypropylene (HDPE), polyvinyl chloride (PVC) and poly (ethylene terephthalate) glycol (PETG) were selected. Non-isothermal TG experiments were carried out under inert conditions at four heating rates, namely 5, 10, 20 and 40 °C/min. The kinetic triplet for raw materials and their blends was determined using Starink, Kissinger-Akahira-Sunose and Ozawa-Flynn-Wall iso-conversional models. Pyrolysis mechanism reactions were explained by diverse models, depending on thermal degradation progress. Results shown that co-pyrolysis followed a complex multi-step reaction mechanism. A synergistic effect was detected during co-pyrolysis of OP/PM mixtures. The addition of 50 % (w/w) OP biomass to PM waste decreased the energy of activation (Ea) from 50 to 25 % for all blends, except for PVC/OP. Thermodynamic analysis reveals that adding OP generally reduces the energy barrier (ΔH), except for PS-OP, and improves energy efficiency (ΔG) by facilitating radical formation and molecular chain cleavage. As a conclusion, this study may open up new avenues for waste valorization and resource recovery. Thus, it may contribute to the transition towards a circular and sustainable economy, through zero waste goal.