The increasing installed capacity of wind power in recent decade has not only yielded enormous level of power generation through green energy and acceleration on energy transformation, but also the troublesome issue of wind turbine recycling, and it is expected that 2 million tons of wind turbine blade waste will be accumulated around the world by 2050. As a result, Lithuanian scientists have proposed a new blade recycling method in the hope of avoiding any potential wastage.
Kaunas University of Technology (KTU) and the Lithuanian Energy Institute (LEI) believe that pyrolysis can be adopted to decompose the glass-reinforced polymer composites (GRP) within wind turbine blades into phenol and fiber. 10% of GRP waste in Europe come from the wind power industry, and other sources also include automobile, ships, and buildings under an annual increase of 6%. With many countries forbidding the entry of composite materials into landfills, it is necessary to start disposing these energy waste that has been climbing in quantity each year.
Samy Yousef, research at Faculty of Mechanical Engineering and Design under KTU, commented that GRP materials are either thermosetting and thermosoft materials, but they are mostly formed with fiber and resin, with the former further segmented into the more expensive carbon fiber and the more common glass fiber.
The research team has further studied fiberglass thermoset materials, fiberglass thermoplastic, and the effect of phenol extraction with and without zeolite catalysts, in order to test out the effect of pyrolysis under different materials. The team also evaluated if adding additive nanoparticles such as carbon black would increase the extraction yield.
As pointed out by the team, the actual yield differs according to the pyrolysis temperature, though generally speaking, additional volatile compounds (66%) and fiber residues (roughly 30%) can be extracted, while the addition of nanoparticles such as carbon nanotubes and graphene would also elevate the production volume of phenol. Yousef commented that the main volatile ingredient is phenol, which can be further used to produce resin, while the fiber reside can also be utilized in multiple directions after chemical purification, including fiber reinforced concrete, polymer composites, and fiber floors, which not only can be recycled and reused, but also ensure low carbon emission.
With that being said, the target for the experiment is merely a sample made by the experiment, instead of actual wind turbine places, where the composition is only roughly the same to that of the latter. As pointed out by Yousef, it is necessary in testing whether the paint on wind turbine blades would affect the outcome, though it should not come as a problem, since the research panel is currently building a model that hopes to further calculate economic and environmental impact.
(Cover photo source: Flickr/soundfromwayout CC BY 2.0)
