Recovery of styrene from waste wind turbine blades (fberglass/ polyester resin composites) using pyrolysis treatment and its kinetic behavior

Abstract

In light of the current economic, environmental and geopolitical challenges related to securing and diversifying energy sources, wind energy has taken a great deal of attention as a sustainable technology for the production of clean energy. However, waste wind turbine blades (WTBs) present a signifcant environmental challenge that requires an efective recy- cling solution, especially fberglass-reinforced polyester resin composite which accounts for a large part of WTBs with high toxicity. Within this context, this research aims to recover styrene compound from WTBs (fberglass/polyester resin) using pyrolysis process. Pyrolysis experiments were carried out using a thermogravimetry (TG) on WTBs and their components, including resin and fber. The formation of pyrolysis vapors is observed using TG-FTIR and GC/Ms measurements. The pyrolysis kinetics of each confguration was studied under diferent heating rates (5–30 °C min−1) using various linear and nonlinear isoconversional modeling techniques. Also, the thermal degradation phases of WTBs were mathematically simulated using the DAEM and IPR models. In addition, the thermodynamic coefcients (enthalpy, Gibbs free energy, and entropy) were determined. TG analysis revealed that the main decomposition reaction site for WTBs was between 350– 490 °C, while the TG-FTIR results showed that (carbonyl (C=O)) was the main functional group in the released pyrolysis vapor. Whereas the GC/MS analysis showed that the released vapor was very rich in styrene compound up to 62% and the maximum recovery rate was obtained at 30 °C min−1 with an increase of 27% compared to that obtained at 5 °C min−1. Regarding kinetic analysis, the results showed that the average activation energies were 182 kJ mol−1 (KAS), 228 kJ mol−1 (FWO), 224 kJ mol−1 (Friedman), and 160 kJ mol−1 (Vyazovkin and Cai) with R2>0.94. Based on these results, pyrolysis treatment can be used to extract styrene from WTBs with high recovery performance.