Recovery of styrene-rich oil and glass fibres from fibres-reinforced unsaturated polyester resin end-of-life wind turbine blades using pyrolysis technology

Styrene is the main compound of unsaturated polyester resin (UPR) of end-of-life wind turbine blades (WTBs) with high toxicity. This research aims to recover styrene and glass fibre (GF) from WTBs composed of GF/UPR using a small pyrolysis plant with a reactor capacity of 250 g. The conversion process was carried out at 25 °C/min at different pyrolysis temperatures: 500, 550 and 600 °C to obtain the optimal temperature at which each UPR fragment can decompose while maintaining the morphology of the recovered GF. The produced gases were monitored during the entire conversion process of WTBs using an instantaneous gas analyzer. The pyrolysis products (oil and gaseous) derived at the end of the process were analyzed using gas chromatography-mass spectrometry (GC/MS). Char and short GF in solid residual products were separated using a sieving process, followed by washing and analysis of their chemical structure and morphology using Fourier-transform infrared spectroscopy, a scanning electron microscope, and an optical microscope. The results showed that at 500°C, WTBs was converted into oil (44.5 %) and solid residues (55 %), while very little amount of gas could be neglected. Also, styrene (upto 48.53 %) was the major compound in the GC/MS analysis of oil product and CO2 was the main gas in gaseous product. However, the recovered GF was still loaded with UPR debris on its surface, which could crack at 600 °C without affecting surface of the recovered GF. Meanwhile, potassium was the major element in char products with concentration in the ranges of 14.9 wt% (500 °C) - 25.5 wt% (600 °C).