Thermo Chemical Processes: Potential Improvement of the Wind Blades Life Cycle

Abstract

Wind power industry has shown a continuous technological improvement that has led to a structural scale up of the blades. The rotor has evolved in the last decades from a maximal diameter of 30 m at the beginning of the 1990s to 171.2 m in 2013. The bigger rotor allows to reach a far better effectiveness (1 MW compared to 7 MW) nowadays.
The stressed evolution of wind blades is principally due to the use of glass fibre reinforced plastics (GFRP) that combine high strength to low price and specific weight. Even if the blade’s length has increased during the last decades, the quantity of GFRP required to install one kW of capacity is still the same.
The old wind blades are made principally of GFRP whose only components are glass fibres (60 % - 70 %) and epoxy resin (30 % - 40 %). The new ones require a better fibrous reinforcement and therefore combine GFRP with a small fraction of carbon fibre reinforced plastic (CFRP). Independently from the type of reinforcement, the operating life time is from 15 to 25 years. According to the EU legislation the GFRP scrap cannot be landfilled anymore but must be recovered.
Aim of this work is to analyse the different recovery processes. In particular this work will be focused on thermo-chemical processes that could be easily integrated in a refinery plant. In order to reduce the environmental impact of the wind blades their full life cycle from cradle to grave has been considered trying to implement the complete reuse of the fibre reinforcement with the potential recovery of the organic fraction after the recycling process.