Oxidative liquefaction as an alternative method of recycling and the pyrolysis kinetics of wind turbine blades

Oxidative liquefaction of wind turbine blades (WTBs) is carried out in a controlled environment having temperature ranges of 250–300 °C, pressure 20–40 bar, oxidant concentration of 15–45%, a reaction time of 30–90 min, and a waste-to-liquid ratio of 5–25 %wt. Fourier transform infrared spectroscopy (FTIR) in the wavenumber range from 650 to 3200 cm−1, analytical pyrolysis at 500 °C was performed. Thermogravimetric analysis (TGA) was employed at a temperature range of 30–800 °C at heating rates of 2, 4, 8, and 16 K/min. The kinetics of WTBs pyrolysis were analyzed using the Fraser-Suzuki (FS) deconvolution method and a model-based kinetic modeling procedure. Oxidative liquefaction resulted in higher resin degradation of WTBs and the production of liquid chemical compounds. Gas chromatography with flame ionization detection (GC-FID) was used to investigate the insight into these chemical compounds which were mostly fatty acids. The resin degradation yield was found to be in the range of 55–100% while volatile fatty acid (VFA) concentrations were from 28.90 to 210.59 g/kg-WTBs. In addition, analysis of variance (ANOVA) have been performed to provide the optimal reaction conditions to maximize the process outputs and minimize the energy consumption to make the process economically feasible.