US backs ‘magic’ wind turbine recycling solution

Washington State University has received a US Department of Energy award to advance a wind turbine recycling solution.

Along with 19 other innovators, the university researchers have won a US$ 75 000 (EUR 69 000) prize in the first phase of a US$ 5.1 million competition. They may get more funds in the second phase.

‘The first generation of wind turbine blades is being retired now,’ says professor Jinwen Zhang who is leading the project. His team has been working on a chemical recycling method to break down the complex composite materials. Thermosets are treated with a mild Lewis acid as the catalyst and an eco-friendly and benign industrial solvent.

The researchers preserve the carbon fibres as well as the resin material in a useful form that can be easily reused. Their formula works at ‘moderate temperatures’ below 200 degrees Celsius and ambient pressure, meaning there is no need for a pressure chamber.

‘A pressure chamber would add additional costs in operation as well as in capital investment,’ notes Zhang. ‘For our system, a high boiling point organic solvent is perfect, and people are used to it in industry.’

The solvent is being hailed as a ‘magic’ ingredient in the recycling process. Its unique chemical properties provide ‘excellent’ separation abilities. After shredding the material into chips, the carbon fibre material is broken down within three hours. The output fractions have the same strength of the original material.

Zhang explains the process can be done in a continuous or semi continuous process without generating secondary waste.

Next, the university team plans to optimise the process, scale it up and demonstrate a semi-batch process.