Optimizing oxidative liquefaction of end-of-life renewables for high-yield chemical recycling

Wind and solar energies serve as the backbone of the renewable energy sector, and the development of pervasive recycling solutions for managing their intricate composite waste streams can be a revolutionary step towards a sustainable renewable energy future. This study is cantered around the concept of producing liquid chemicals through the oxidative degradation of the existing polymer matrix in both wind turbine (WTB) and photovoltaic (PV) panels. The oxidative degradation process is executed based on a set of experimental design conditions (central composite design for WTBs and central composite + fractional factorial design for PV waste). The effect of five independent process variables, namely temperature, pressure, reaction time, waste-to-liquid ratio, and oxidant concentrations (250 – 350°C, 20 – 40 bar, 30 – 90 minutes, 5 – 25 %, and 15 – 45 % for WTBs; and 200 – 300°C, 30 bar, 45 minutes, 12.5 – 37.5 %, and 30 – 60 %), has been investigated on process output. Total polymer degradation (TPD) was calculated, and the obtained liquid fraction was analysed through gas chromatography with flame ionization detection (GC-FID) to identify the existing chemical fractions. An analysis of variance (ANOVA) was performed based on the obtained results to identify the optimal reaction parameters for maximizing the yields of individual narrow fractions appearing during the oxidative liquefaction of WTBs and PV panels. This study aims to contribute significantly to the scalable, high-yield chemical recycling of end-of-life renewables.