IIT Mandi Recycles Polymers with Microwaves, Makes Wind Turbine Blades

To quickly and sustainably produce wind turbine blades, researchers at the Indian Institute of Technology, Mandi, have employed microwaves to recycle polymer composites. Compared to the alternatives now in use, such as landfills and thermal-based recycling, the institute said that this method is quick and sustainable. The Journal of Resources, Conservation and Recycling has published the study’s findings.

The team claims that there is a push for renewable energy sources like wind energy to be used to overcome the downsides of fossil fuel-based electricity. India installed 40.893 GW of wind power systems in total as of July 2022, making it the fourth-largest wind energy system installer in the world.

Wind power is captured by placing wind turbines (also known as windmills) in key locations across the nation. These wind turbines’ blades are comprised of polymer composites, which are polymer systems into which strong fibres like carbon and glass fibres have been inserted.

“We have created a microwave-assisted chemical recycling (MACR) procedure that is environmentally friendly for recycling glass fibre reinforced polymer (GFRP) composite waste. Additionally, we used microwaves to speed up the chemical breakdown of GFRP composites using acetic acid and hydrogen peroxide. Both hydrogen peroxide and acetic acid, which is found in vinegar and is often used as a disinfectant or antibiotic, are eco-friendly chemicals,” according to Sunny Zafar, an assistant professor at the school of mechanical and materials engineering.

When the wind turbine blades reach the end of their useful lives, according to Zafar, the decommissioned constructions consisting of glass fibres in epoxy polymers are destroyed and either landfilled or burned.

“Both disposal techniques raise costs and environmental pollution. Between 2024 and 2034, it is expected that wind turbine blades will produce roughly 2,000 tonnes of composite trash worldwide. This defeats the advantages wind energy has for the environment. Additionally, limitations on waste disposal and shifting raw material prices could push up the price of these composite materials used in wind turbine blades,” the expert said.

The team from IIT Mandi has created a quick and environmentally friendly process to recycle the fibres found in the composites used to make wind turbine blades.

The researchers discovered that their approach had a 97.2% breakdown rate for epoxy while still recovering the glass fibres. In comparison to virgin fibres, “the recovered fibres retained more than 90% of the other mechanical qualities and about 95% of the strength,” Krishnan added.

The use of green chemistry and the absence of harsh chemicals in the extraction process made this effort particularly distinctive. According to Venkata Krishnan, associate professor at the School of Chemical Sciences at IIT Mandi, “The recycling approach we have devised can result in a significant shift in recycling technology, which can assist the nation move towards a circular economy for wind turbine blades.”