NCC team claims first after recycling continuous carbon fibres from pressure tanks
4 May 2022
Engineers at the National Composites Centre in Bristol are hailing a “significant milestone in the development of Britain’s hydrogen capability” after reclaiming continuous carbon fibres from a whole pressure vessel to manufacture a new pressure vessel.
NCC, the UK’s centre of excellence for advanced composite applications, collaborated with SME partners B&M Longworth Ltd and Cygnet Texkimp, to achieve what they say is a first in the UK.
CEO of Cygnet Texkimp Luke Vardy described the breakthrough:
“Not only does this technology have the potential to transform end-of-life outcomes for composites, but it also shows how we can do so without compromising the essential properties of the fibre,” he stated.
“That commitment to fibre integrity is extremely significant because it allows us to reclaim and repurpose carbon fibre in a way that is reliable and sustainable, while creating end products of the highest quality and consistency.”
Partnering with Lancashire-based B&M, the NCC team reclaimed continuous carbon fibre, from end-of-life composite pressure tanks, using the company’s DEECOM process.
As the gas has low energy density it needs to be compressed and stored at very high pressures, between 350 to 700 bar (5,076 – 10,152 psi). This makes high-strength, lower-weight carbon fibre the material of choice, especially for hydrogen pressure vessels in vehicles such as cars or aircraft, where power-to-weight is critical.
Demand for carbon-fibre is expected to grow five-fold between 2025 and 2030, exceeding global manufacturing capacity. Creating viable, low cost recovery processes, that retain the inherent strength of continuous carbon fibres for recycling, is therefore key to the development of the hydrogen economy.
Until recently, recycling processes for composite components such as wind turbine blades has resulted in short fibres with lower mechanical properties than virgin fibre. Although useful the material is unsuitable for re-use in high performing products.
Originally designed to remove waste polymers from filters and production equipment, the process uses superheated steam, under compression, to penetrate microscopic fissures in the composite’s polymer, where it then condenses.
On decompression, it boils and expands, cracking the polymer and carrying away broken particles. This pressure swing cycle is then repeated until all the matrix has been separated from the fibre, allowing the monomers to also be reclaimed for possible reprocessing.
The DEECOM process leaves the primary component material intact and undamaged, allowing for any length to be retained. National Composites Centre engineers working with fibre handling and conversion technology leaders Cygnet Texkimp could employ the reclaimed continuous carbon fibre to make a new pressure vessel using filament winding.
Fibre recovery and recycling project forms part of the centre’s Hydrogen programme, developing and sharing the technical knowledge, cross-sector composite expertise and state of the art technology that businesses need to achieve their hydrogen ambitions.
Announcing the project results, NCC chief engineer, hydrogen, National Composites Centre Marcus Walls-Bruck, said continuous fibre recovery was a significant step towards the goal of a fully recyclable certified tank – the critical technology barrier to embed hydrogen in the energy mix and meet net zero targets.
B&M Longworth director Jen Hill concluded:
“Recent projects have seen success in a range of composite panels and automotive parts, so a move towards hydrogen tanks was the next logical challenge.”
“By pulling together we can onshore advanced material production, optimise reuse, reduce import and supply chain issues and improve the UK’s export potential, all while leading on sustainability in composites.”
