Co-pyrolysis of waste wind turbine blades and biomass and their kinetic analysis using artificial neural network

Abstract

This research aims to study co-pyrolysis of waste wind turbine blades (WTB) and biomass using a thermogravimetric (TG) analyser at various heating rates (10, 20, and 30 °C/min). The experiments were performed on WTB consisting of a glass fibre/unsaturated polyester resin (UPR) and woody biomass (WBs) at different mixing ratios (1:1, 2:1, 3:1 w/w). The effect of a mixing ratio and a heating rate on composition of vapours released from the co-pyrolysis process was observed using TG-FTIR and GC-MS. Also, the co-pyrolysis kinetic and thermodynamic behaviour of the WTB/WBs mixtures was studied. Meanwhile, the experimental TG curves were mathematically simulated using the Distributed activation energy method and the Independent parallel reactions, while unknown curves were predicted using an artificial neural network (ANN) model. The differential thermogravimetric results showed high compatibility between WTB and WBs (1:1 and 2:1) with a single decomposition peak, which is indicates that both feedstocks were degraded as a single-step reaction. While the higher mixing rate (3:1) revealed double decomposition peaks, indicating that the mixture undergoes two sequential decomposition reactions and several competing reactions occur simultaneously, which increases the complexity of the decomposition process. Meanwhile, the GC-MS results showed that the mixture of WTB/WBs (1:1) could significantly reduce the styrene (the main toxic compound of UPR) from 62% (in neat WTB) to 7 % at 30 °C/min. Also, presence of other aromatic hydrocarbons (benzoic acid, 2-Methoxy-4-vinylphenol, etc.) was observed in the mixture samples as a result of styrene cracking. Finally, the kinetic model-free isoconversional results showed that Ea was estimated at 275–383 kJ/mol (WBs) and 196–286 kJ/mol (WTB/WBs). Accordingly, co-pyrolysis of WTB with WBs is highly recommended to valorise WTB and eliminate their toxic styrene compound