Making green energy greener: Researchers propose method for wind turbine blades' recycling

Date:
March 15, 2022
Source:
Kaunas University of Technology
Summary:
Wind turbine blades made from glass fiber-reinforced polymer (GFRP)
laminate composites can serve for up to 25 years. After that,
they end up in landfills which has become a real challenge for
the renewable energy industry. Researchers have proposed a method
for wind turbine blades' recycling. Using pyrolysis, they broke
the composite materials into their constituent parts. According to
scientists, the extracted materials can be reused, and the process
is virtually waste-free.



FULL STORY ==========================================================================
A group of researchers from Kaunas University of Technology (KTU)
and the Lithuanian Energy Institute proposed a method for wind turbine
blades' recycling. Using pyrolysis, they broke the composite materials
into their constituent parts -- i.e., phenol and fibre. According to scientists, the extracted materials can be reused, and the process is
virtually waste-free.


==========================================================================
Wind turbine blades made from glass fibre-reinforced polymer (GFRP)
laminate composites can serve for up to 25 years. After that they end
up in landfills - - GFRP is recognised as hard-to-break-down. This has
become a real challenge for the renewable energy industry.

It is estimated that wind turbine blades account for 10 per cent of
Europe's fibre-reinforced composite material waste. Researchers claim
that by 2050, wind turbine blade waste will increase to around two
million tonnes globally. With many countries banning composite materials
from their landfills, recycling the used wind turbine blades becomes a challenge that researchers around the world are trying to solve.

"The aim of cutting global greenhouse gas emissions to close to zero
by 2050 has been voiced several years ago. Since then, more and more
countries have been committing to the net-zero goal by investing in
renewable energy resources, including wind energy. However, the recycling
of the wind turbine blades, which are as long as a football field, very
sturdy and include plastic, is the main problem. Without a feasible
solution to it, we cannot say that wind energy is fully sustainable
and environmentally friendly," says Dr Samy Yousef, a researcher at
Kaunas University of Technology (KTU), Faculty of Mechanical Engineering
and Design.

Aiming to tackle this challenge, the research group headed by Dr Yousef
have made several experiments involving decomposing GFRP into its
constituent parts.

Waste-free conversion Due to its strength, shaping simplicity and low manufacturing costs GFRP composites are used for a multitude of purposes
-- for car manufacturing, maritime vessels, oil and gas production, construction, sporting goods and more. Aircraft, wind energy and
electronics are among the industries which use the GFRP most, with the
global demand increasing annually by 6 per cent.



========================================================================== "GFRP composites used for many industries including wind turbine blades manufacturing are either thermoset or thermoplastic. In either case,
they roughly consist only of two components -- fibre and resin (in
some cases with different micro or nanoparticle additions). As for the
fibre, it usually is carbon fibre or fibreglass (the latter is cheaper)" explains Dr Yousef.

During the experiments, the research group were applying pyrolysis
(in presence of zeolite catalysts and without) to different batches
of composites - - fibreglass thermoset and fibreglass thermoplastic
-- measuring the extraction of phenol (the primary component in the
production of phenolic resins and the manufacture of nylon and other
synthetic fibres) in each case. After that, they were analysing the basic
raw materials from each batch. The researchers also assessed the effect
that the additive nanoparticles (such as carbon black) can have on the
yield of useful components.

Although the yield of the components extracted during pyrolysis differs depending on the temperatures applied, the proximate measurement revealed
that in all the cases the numerous volatile compounds (up to 66 per
cent) and fibre residue (around 30 per cent) were extracted. The added
fibre nanoparticles (Carbon nanotubes and graphene) increased the yield
of phenol.

"The volatile components are basically phenol, which can be used for
further production of resin, and the fibre residue can have numerous applications after purifying it chemically -- for fiber-reinforced
concrete, polymer composites, fiber flooring. Our method is virtually waste-free with some small emissions, which is standard in this kind of conversion operation," says Yousef.

Needs a real wind turbine blade to continue research The experiments
were conducted using the samples prepared at a laboratory which had compositions similar those used for making wind turbine blades, and not
the wind turbine blades themselves. Therefore, Dr Yousef notes, there is
a need to assess the effect of the paint coating, that the real turbine
blades are covered with, to the results. However, he believes that it
will not be significant.



==========================================================================
"We would of course be happy to receive a worn-out wind turbine blade,
which is no longer usable, and to conduct our experiments with the
samples obtained from the real object," says Yousef.

At the moment, the research group is creating a model, which would allow
to scale and calculate the wider economic and environmental impact of
the results.

This study is one of the several conducted by the same research group,
which focus on the practical implementations of the principles of
the circular economy. Last year, their experiment of lint microfibre
conversion into energy received broad international attention.

"We are developing research in numerous topics related to climate change, extracting of clean energy (H2 and CH4) using membranes technology, and transition to the circular economy as these topics are closely related
to the future of our planet," says Dr Yousef.


========================================================================== Story Source: Materials provided by Kaunas_University_of_Technology. Note: Content may be edited for style and length.


========================================================================== Journal Reference:
1. Samy Yousef, Ieva Kiminaitė, Justas Eimontas, Nerijus
Striūgas,
Mohammed Ali Abdelnaby. Catalytic pyrolysis kinetic behaviour of
glass fibre-reinforced epoxy resin composites over ZSM-5 zeolite
catalyst.

Fuel, 2022; 315: 123235 DOI: 10.1016/j.fuel.2022.123235 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/03/220315112941.htm

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