Transporting hydrogen safely and cost-effectively

The benefits:

• extremely lightweight
• non-corroding
• fatigue-resistant
• durable

The new European Climate Law requires Europe to become climate neutral by 2050.

Emissions must be reduced at least 55% from 1990 levels by 2030. These targets cannot be achieved without hydrogen. They require special technologies and innovations – and companies to tackle this challenge. Hexagon Purus is a case in point: It is the world’s leading player in hydrogen storage, having made a name for itself with innovative storage solutions. Hexagon Purus has been part of Norway’s Hexagon Composites ASA, the world’s leading supplier of high-pressure composite cylinders for compressed gases, since 2016.

Hydrogen transport options

Countries around the world can only become hydrogen nations if the hydrogen is also transported– after all, production and end-use locations are often far apart from each other. This generally takes three
forms. First, hydrogen can be transported as liquefied gas.
However, this requires considerable energy because the gas condenses only at temperatures below minus
252 degrees Celsius. Other disadvantages include strict storage requirements and the requisite complex
infrastructure that only makes economic sense to build for large quantities of liquid hydrogen.
The second option is to chemically bond the hydrogen to base materials such as nitrogen to generate ammonia, or liquid organic hydrogen carriers (LOHCs). Once bonded to the substrate, these base materials offer favorable properties such as high energy density.

They make them ideal choices for transporting large quantities of hydrogen over long distances by ship or other transport modes, but both options are less ideal or have very limited utility in mobility applications.

The liner in Type 4 cylinders is made of a polymer plastic. They are the lightest cylinders.

Hexagon Purus maintains a global marketleading presence with its Type 4 high-pressure composite cylinders and systems. The company pioneered the introduction of Type 4 technology in hydrogen transport in 2012. Today, all major gas distributors are among the clients. Hexagon Purus has developed cylinders and systems for hydrogen distribution for pressures of 250, 300, 380, 500 and 635 bar.

A Type 4 cylinder weighs about 75% less than a Type 1 cylinder. This has a big impact on the payload; after all, the total permissible weight for trucks is 40 metric tons in most of the EU countries. For example, transporting 500 kilograms of hydrogen in Type 2 cylinders in a 30 ft container brings you close to the total permissible weight of 40 metric tons, after including the chassis and tractor. “Our Type 4 cylinders make it possible to transport over twice the volume of hydrogen on a truck: We can transport over 1150 kilograms of hydrogen at a pressure rating of 381 bar in a 45 ft container – with a total vehicle weight of 33 metric tons,” said Jan Michael Geck, Project Manager at Hexagon Purus for distribution systems. In Europe, a new EN 17339 standard allowing higher payloads and pressures has been in place since this year. Hexagon Purus is therefore developing systems for transporting 1,400 to 1,500 kilograms of compressed hydrogen at pressures 500 and 635 bar. To be sure, Type 4 systems require a larger upfront investment than Type 1 steel systems. “However, between the lower weight and the ability to transport significantly more hydrogen with one truck, the operational costs are much lower,” added Felix Grass, Sales Director Europe Hydrogen Distribution at Hexagon Purus. “The total cost of ownership (TCO) is unbeatable with a Type 4 solution in the vast majority of applications.” Another advantage is the very high long-term stability of Type 4 cylinders. Requalification tests at 300 and 381 bar show that the cylinders exhibit no signs of material fatigue, even after 50,000 cycles – which is a multiple of the standard specification. In other words, Hexagon Purus manufactures the cylinders for nonlimited lifetimes. Hexagon Purus Type 4 cylinders also excel in their corrosion resistance: Only the metal bosses that are used to mount the cylinders and connect them to the tubing are made of stainless steel, so the cylinders are extremely resistant to corrosion and virtually made for harsh climates or sea transport. “We manufacture our modules in sizes ranging from 10 to 45 feet and offer flexible solutions for our customers,” said Geck.

Hexagon Purus does not compromise on the safety of dangerous goods containers. The containers are subjected to various simulated and real load tests during development and homologation.

The Type 4 composite cylinders have to pass around 15 highly demanding mechanical, chemical and thermal
load tests during homologation. After successful approval, each finished distribution system is leaktested
and inspected and approved by a notifying body prior to shipment.

Hexagon Purus relies on a wide variety of safety features that build on one another. This also includes safety against fire. “If there is a fire, our fire protection system will ensure that TPRDs (temperature pressure relief devices) blow off the gas in a controlled manner, thus preventing the cylinders from bursting,” said Geck.