Tsinghua Turns Old Wind Turbine Blades Into Graphene in 0.5 Seconds

The researchers first grind the blades into powder and mix it with carbon black to make it conductive. An ultrafast Joule heating pulse then takes it to roughly 2,000 °C in 0.5 seconds. The silica in the glass fibre becomes silicon carbide, while carbon compounds from the resin form graphene. The glass and resin do not need to be separated first, and no solvents or catalysts are required.

Results and economics

Added to new epoxy resin at just 0.3% by weight, the recovered material raised tensile stiffness by 27% and flexural stiffness by 9%. At 0.1%, thermal diffusivity improved by 41%. The team says this could yield stronger, longer-lasting blades and even help with ice build-up.

By the team's calculations, processing a tonne of waste could earn about $80, against estimated losses of $460 for pyrolysis and $1,800 for certain chemical treatments. Emissions would fall 83% compared with pyrolysis and 92% compared with chemical dissolution. These estimates exclude shredding, equipment and other operating costs.

The scale problem

Most experiments used only 0.3 grams of material. Batches have reached 10 grams, and a reactor for 200 grams has been designed but not yet proven. Blades from a single turbine can weigh tens of tonnes. Deng aims to build a pilot plant handling 100 tonnes. No full blades have been built yet, and the results come from laboratory resins.

James Tour of Rice University, a pioneer of flash Joule heating, says the work shows how hard-to-recycle waste can become valuable material, but notes that industrial effectiveness remains to be shown. Energy use and long-term durability also need testing.