From the Sector

Fibre-reinforced pressure vessels are increasingly becoming the cornerstone of the hydrogen economy, playing a key role in the transport, storage and use of hydrogen for both mobile and stationary applications. AZL Aachen GmbH, in collaboration with a consortium of 25 leading industry players, has successfully completed a 12-month R&D project entitled 'Trends & Design Factors for Hydrogen Pressure Vessels'.

The 550-pages report, presented to the 40 participants of the final project meeting in November, provides a comprehensive overview of the market and technology trends related to the development of thermoset and thermoplastic pressure vessels. By addressing material impacts, complex design considerations and advanced manufacturing technologies, the project provides business- and technology insights. Companies along the whole value chain of pressure vessels have been involved, resins, fibres, liners, production systems, vessel manufacturers, hydrogen system integrators and OEMs.

The first phase of the project involved an in-depth review of regulations, requirements and safety standards, together with examples of state-of-the-art hydrogen pressure vessels. Key aspects covered included manufacturing processes, supply chains and production technologies, as well as a comprehensive patent analysis. In addition, the study examined winding patterns, design strategies, material models and software tools used in the development of pressure vessels.

The second phase of the project involved extensive engineering studies. Warden Schijve, Design Leader at AZL, explained the procedure: "Our team of experts developed CAE models for 12 different layouts of a two-metre, 350-litre Type IV pressure vessel designed for 700 respectively 350 bar applications. These models incorporated different resin and fibre types, layup variations and boss designs to evaluate the impact on mechanics, weight, cost and carbon footprint. We also explored hybrid fibre combinations and dome reinforcement using patch technologies. Detailed process chain modelling provided further insight into cost structures and CO2 footprints.”

The results of the project also show initial future trends: Through the targeted use of advanced material combinations, adapted designs and manufacturing techniques, it is possible to significantly reduce the weight and cost of the vessels while maintaining the necessary safety standards. Compared to state-of-the-art vessels, hydrogen over tank weight efficiencies could be improved from the standard 6 to 7% up to more than 11%. These developments could strengthen the competitiveness of hydrogen technology in various mobility and energy sectors in the future.

“The knowledge gained from the project provides a solid foundation for the use of new technologies to meet the hydrogen economy's requirements for safe and cost-effective pressure vessels,” commented Celal Beysel, Chairman of the Board at FLOTEKS Plastik San. Tic. A.Ş. Floteks, a Tier 1 supplier of plastic components, has launched numerous R&D initiatives in the design and development of Type IV vessels in recent years. In 2023, the company joined the AZL Composite Pipes and Vessels Working Group and the 'Trends and Design Factors for Hydrogen Pressure Vessels' project. Beysel added: "We are pleased to announce that Floteks has established a new company called Pressura in 2024, which will focus on the production of type 4 pressure vessels for buses and trucks."

Companies and organisations seeking detailed insights or collaboration opportunities are encouraged to contact AZL. AZL Aachen GmbH serves as an innovation partner for hydrogen tank development, prototyping and testing, and is dedicated to advancing composite technologies.

The EU's planned ban on the entire group of per- and polyfluoroalkyl substances (PFAS) would endanger many industrial processes, states VDMA Textile Machinery. Textile manufacturing would be affected twice – by missing important chemicals for technical textile production and by the lack of indispensable textile machine components. The latter would affect the whole supply chain from textile machinery manufacturers and its suppliers to the textile industry in the EU.

Solid PFAS parts are widely used in textile machinery production, especially where extreme conditions prevail. Verena Thies, Managing Shareholder Thies GmbH & Co. KG, explains: “Our textile dyeing machines are world leaders and set standards in efficiency and sustainability. They work under pressure at temperatures of up to 140° C using highly acidic, highly basic and/or oxidative or even reductive chemicals. This is precisely why PFAS is needed, for example, in seals and rings, flaps as well as valves for a long-lasting and high-quality machine concept – because there are no alternatives with qualitatively equivalent properties. In addition, PTFE semi-finished products enable a sliding and gentle contact with the textile fabric in ecologically important techniques in the transformation of textile wet finishing."

PTFE and also FKM are fluoropolymers (fluoroplastics and fluoroelastomers), a group within the broad PFAS range of about 10,000 substances which would be banned for production, use and sale in the EU. They are high-tech materials, and as so-called "polymers of low concern" are not a danger to the environment, according to the OECD. Furthermore, these components are installed inside a machine and exchanged or disposed of properly. PFAS such as PTFE and FKM must be exempted from the ban, demands the VDMA in its position paper.

"In this way, the association also supports the approach taken in Great Britain. With the 10,000 substances, everything is lumped together, although the various PFAS groups are very different," warns Dr Sarah Brückner, Head of VDMA Environmental Affairs and Sustainability. "We should take our cue from the UK and look at the substance groups in a differentiated way."
Apart from several types of dyeing machines, PFAS components are indispensable in textile drying machines (e.g., conveyor dryers, tumblers and stenters) and damping machines. They are also used in fully automatic chemical dispensing systems and pressure vessels for thermochemical treatment of textile recycling material, heat recovery systems and wastewater treatment technology. This means that a lot of machines needed for a sustainable textile production would be affected by the PFAS ban.

VDMA Textile Machinery will take part in the ongoing EU public consultation. The association will describe indispensable key functionalities and conditions of use in the textile machinery sector as well as the consequences for the companies and the customers in the EU if the ban is imposed. The consultation ends on September 25, 2023, and VDMA urged its members affected by the planned restriction to participate in the consultation at an early stage. This is the only way to ensure that the broad scope of the mechanical and plant engineering sector is represented.