Hydrogen Fuel Systems Demand a Safe Pair of Hands
By Fabian Brücker and Graham Johnson explores Parker Hannifin’s certified materials, advanced safety designs, and H₂-qualified components ensuring safe, efficient hydrogen fuel systems.
www.parker.com
On 16th July 1969, NASA’s Apollo 11 spacecraft launched from the Kennedy Space Center, Cape Canaveral, with the aim of putting the first men on the moon. On board were Neil Armstrong, Buzz Aldrin, Michael Collins, and a broad spread of products supplied by Parker, including those for the hydrogen (H2) and oxygen (O2) fuel cell systems. Over the years, Parker’s solutions have helped to facilitate many successful and safe space missions. The company’s ball valves, stop valves, check valves, shut-off valves, seals, O-rings, tubing, and fittings, all contribute to the operation of fuel cell reactant supply modules and H2/O2 modules. Today, following more than five decades of experience in H2 solutions, Parker is at the forefront of this exciting technology as modern industry taps into its many benefits.
For some companies, H2 is a new concept, but for Parker, it is an established technology. As a result, there will be Parker solutions on the new Artemis mission spacecraft that will see humans return to the moon, currently scheduled for 2026. The company also has extensive road transport experience. Around 15 years ago, a manufacturer in Belgium produced the world’s first H2-fuelled bus with Parker couplings proving central to its safety and success.
Be Safe, Not Sorry
Many industries are today taking advantage of H2, including oil and gas, fertilizer manufacturing, steelmaking, and cement production. Topping the priority list in all of these sectors is safety. H2 presents many benefits for users, but many challenges for engineers who need to ensure optimal safety in all applications, whether it involves H2 production, conditioning, storage, distribution, or usage.
Typical H2 system components include those for fluid delivery lines. As the smallest molecule, H2 has a high tendency for diffusion and permeation. It also features a high flow rate in the event of a system leak. Piping and seals need to be suitable for H2 use over the system’s entire operating life.
Further key components are those for flow control, including valves, check valves, and regulators. These components can offer manual operation or remote control using electric or pneumatic actuators. Actuators require careful design to avoid inadvertently presenting a source of ignition, particularly if they are electric in nature.
What To Look Out For
Among the potential hazards and issues associated with H2 systems are flammability, explosivity, the small size of the molecule, the absence of color and odor (in H2 gas), its interaction with materials (the embrittlement of certain metals can promote catastrophic failure), elevated storage pressures, and health hazards such as burns and asphyxiation. This list helps to identify the focus of concerns in the design and operation of H2 systems. The options available to design engineers looking to address hazards (in order of preference) are: eliminate, prevent, avoid, mitigate, or accept. Achieving many of these options will involve the specification of suitable H2-compatible products.
Of course, any H2 system should have a fail-safe design involving redundant safety features like pressure-relief devices, backup critical components and systems, and fail-safe positions for valves. Valves should automatically revert to the safe position in the event of a power failure, for example.
Introducing automation into safety design concepts involves the remote monitoring of critical information, remote operation, and the automatic limiting of operating conditions like pressure or flow rate, as well as the automatic operation of appropriate equipment upon the detection of H2. Actions here might include closing shut-off valves, turning ventilation on or off as required, and initiating appropriate shutdown operations.
Material Matters
H2 is extremely adept at finding flaws and establishing leaks in materials with defects or inclusions. This topic therefore demands close attention during system development. Design engineers must ask: what constitutes a high-quality component material able to resist brittle surface fractures and crack propagation? While many component suppliers for H2 systems point almost exclusively to a material’s chemical composition, in truth there are many other governing factors, including operating environment, mechanics (internal and external factors), and specific characteristics of the microstructure.
While chemical composition and mechanical properties are of course paramount when it comes to microstructure, so is the quality of the material’s manufacturing process and its subsequent heat treatment. Improper or non-controlled heat treatment can result in high densities of undesirable phases and inclusions in the raw material. In turn, these defects can lead to a compromise in the service life of H2 system components, sometimes prompting sudden catastrophic failure.
Developers of H2 systems can protect themselves by working with suppliers that offer valid material certificates with traceability information to demonstrate the quality of metals. These certificates will certify technical parameters, manufacturing routes, heat-treatment details, test results, chemical analysis, mechanical characteristics, and compliance with national/international standards. Material certificates provided by Parker include full provenance. The company can trace the material used to make each H2 system component right back to the mill. Moreover, stringent manufacturing processes avoid H2 pre-charge into the material.
Material is not the only issue influencing design safety in H2 systems. H2 storage typically takes place at low temperatures and high pressures. Low temperature enhances H2’s ability to attack the container’s material, while high pressure makes leakage more likely. Appropriate component selection is vital.
Some OEMs within the H2 industry procure lower-cost components because they feel overwhelming pressure to be competitive. Certification is not mandatory and there is nothing to stop suppliers from offering poor-quality components at an attractive price. The issue in the H2 sector therefore becomes one of awareness and understanding, particularly among buyers. Buyers must be confident in the breadth and depth of the supplier’s product range, its experience in handling H2, and its training and support services.
Play It Safe
Parker offers everything necessary to assure safe, reliable H2 system installations. The company has a long history of handling H2 media and has in-depth H2 industry information relating to safety, which is essential to customers who must make a case for safety when proposing H2 solutions.
In addition to robust materials certification, Parker has invested in obtaining H2-specific qualifications, such as EC-79 for transportation, ISO 15848 for fugitive emissions, and ISO 19880-3 regarding the requirements and test methods for the safety performance of high-pressure gas valves at hydrogen fueling stations. In addition, components comply with the US HGV accreditation standard, which is an alternative to EC-79 and will see harmonization with respective ISO standards.
For H2 applications, the company offers an extensive list of H2-compatible components that enable safe and efficient operations across the entire range of H2 system pressure and temperature extremes. These include hose assemblies that operate in high-pressure H2 dispensing and transfer applications, double-ferrule tube fittings as well as fittings in inverted two-ferrule compression design for process instrumentation, medium-pressure cone and thread fittings and needle valves for autoclave applications, and O-ring face seal tube fittings and adapters for on-vehicle high-pressure connectors.
Brave New World
If working on H2 systems is a relatively new concept for an organization or its employees, it may not be immediately apparent why choosing the right components and assembling them correctly is so critical for safe and reliable operation. A system with poor components may work well after initial commissioning, but problems will soon arrive as the H2 degrades the fittings, for example.
Engineers can avoid these problems by discussing their requirements with Parker, which offers products, component training courses, and worldwide component support from a single source.
www.parker.com
