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.
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.
Partnering with Lancashire-based B&M Longworth Ltd, the National Composites Centre team successfully reclaimed continuous carbon fibre, from end-of-life composite pressure tanks, using the company’s revolutionary DEECOM process.
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 (the material suspended in the polymer) has been separated from the fibre, allowing the monomers to also be reclaimed for possible reprocessing.
As a result, National Composites Centre engineers working with Cygnet Texkimp Ltd, a Cheshire-based, global leader of fibre handling and conversion technology, could use the reclaimed continuous carbon fibre to make a new pressure vessel using filament winding.
The partnership is now looking to work with manufacturers to scale and industrialise this process, sharing the knowledge of recent recycling trials. The next step is to undertake fibre characterisation analysis of the reclaimed material and recycled vessel, as the team works towards their ultimate goal: developing the disruptive technologies that enable sustainable hydrogen storage solutions.
