Chemical Recycling Methods for End-of-Life Wind Turbine Blades
Topic(s) : Special Sessions
Co-authors :
Maria MODESTOU (GREECE), Dionisis SEMITEKOLOS (GREECE), Christina PODARA (GREECE), Costas CHARITIDISAbstract :
The extensive use of fibre-reinforced polymers in various sectors, such as aerospace, automotive, and wind energy, is continuously expanding due to their lightweight nature, energy-saving attributes, and mechanical properties. However, their widespread use has raised significant questions regarding their end-of-life (EOL) management, as there are currently no standardized guidelines provided by any regulatory body regarding the EOL disposal of these materials. Extensive re-search funded by the EU is being conducted, focusing on recycling fibre-reinforced polymers structures, particularly in the field of wind energy.
As the wind energy develops rapidly, becoming one of the most promising renewable energy sources over the last two decades, the need for efficient ways to recycle the wind turbine blades (WTB) is becoming increasingly critical.
This study focuses on identifying WTB wastes’ composition and investigating chemical recycling methods utilizing sol-vents, in order to recover fibres in their optimal state for subsequent reuse in fabrication of new composite materials.
Main processes of chemical recycling are taking place at low temperatures and ambient pressure, and at near- or super-critical conditions, offering a large number of possibilities due to theirs wide range of solvents, such as water, alcohols, acetone, glycol, or acids, catalysts, temperature, and pressure, in order to break down the chemical bond of the polymer matrix, either epoxy, polyester, or phenolic.
WTB underwent Solvolysis treatment, using a 500ml round flask with magnetic stirring, utilizing a Poly(ethylene gly-col)/NaOH system at 200 °C at ambient pressure, varying parameters such as time, and composite waste and NaOH mass. Identification of WTB wastes, as well as optimum conditions of process, were assessed with analysis through FT-IR and TGA, and surface morphology through SEM analysis. Based on literature review, WTB waste composites predom-inantly consist of polyester resin with epoxy resin, a finding that has been confirmed through FT-IR. Based on TGA and SEM, optimum conditions involve the use of 200 gr PEG200, 12.5 gr NaOH, and 10 gr GFRPs for 6 hours at 200 °C, with a high decomposition efficiency of 83%.
Upscaling of process has also been performed in a 10-liter batch reactor, with mechanical stirring. The observation re-vealed that a slightly smaller ratio of NaOH was required for the process to yield same results, due to the transition to mechanical stirring, since it delivers higher torque, rendering them suitable for more viscous or challenging reactions that demand increased mixing power.
Subsequently more environmentally sustainable solvents, such as water, alcohols, and acetone, at near- or supercritical conditions are tested, for a more energy efficient process.
In conclusion, this study successfully demonstrates the feasibility of chemical recycling for WTB waste, contributing sig-nificant insights into the field of Solvolysis and WTB recycling.
As the wind energy develops rapidly, becoming one of the most promising renewable energy sources over the last two decades, the need for efficient ways to recycle the wind turbine blades (WTB) is becoming increasingly critical.
This study focuses on identifying WTB wastes’ composition and investigating chemical recycling methods utilizing sol-vents, in order to recover fibres in their optimal state for subsequent reuse in fabrication of new composite materials.
Main processes of chemical recycling are taking place at low temperatures and ambient pressure, and at near- or super-critical conditions, offering a large number of possibilities due to theirs wide range of solvents, such as water, alcohols, acetone, glycol, or acids, catalysts, temperature, and pressure, in order to break down the chemical bond of the polymer matrix, either epoxy, polyester, or phenolic.
WTB underwent Solvolysis treatment, using a 500ml round flask with magnetic stirring, utilizing a Poly(ethylene gly-col)/NaOH system at 200 °C at ambient pressure, varying parameters such as time, and composite waste and NaOH mass. Identification of WTB wastes, as well as optimum conditions of process, were assessed with analysis through FT-IR and TGA, and surface morphology through SEM analysis. Based on literature review, WTB waste composites predom-inantly consist of polyester resin with epoxy resin, a finding that has been confirmed through FT-IR. Based on TGA and SEM, optimum conditions involve the use of 200 gr PEG200, 12.5 gr NaOH, and 10 gr GFRPs for 6 hours at 200 °C, with a high decomposition efficiency of 83%.
Upscaling of process has also been performed in a 10-liter batch reactor, with mechanical stirring. The observation re-vealed that a slightly smaller ratio of NaOH was required for the process to yield same results, due to the transition to mechanical stirring, since it delivers higher torque, rendering them suitable for more viscous or challenging reactions that demand increased mixing power.
Subsequently more environmentally sustainable solvents, such as water, alcohols, and acetone, at near- or supercritical conditions are tested, for a more energy efficient process.
In conclusion, this study successfully demonstrates the feasibility of chemical recycling for WTB waste, contributing sig-nificant insights into the field of Solvolysis and WTB recycling.