A. Dominguez, Swagelok Company, Solon, Ohio
the world moves toward a low-carbon energy future, the race for viable fossil
fuel alternatives continues, with hydrogen (H2) having significant
potential to revolutionize energy. Multiple analysts forecast it will continue
its exponential growth as countries worldwide discover how well H2
produced through electrolysis works. The questions surrounding its long-term viability focus on how easily it can be
produced and how much global capacity will exist.
Ensuring reliable H2
production begins with the centerpiece technology of the production process:
optimized electrolyzers (FIG.
1). Typically, production facilities can use one of two primary
configurations of their electrolyzers [e.g., alkaline and proton exchange
membrane (PEM) electrolyzers] to convert water and electricity into H2
and oxygen. Efficient, effective conversion depends on the electrolyzer’s
reliable water delivery and functional outflow of the resultant gases.
As engineers design H2
production facilities, they must focus on creating well-constructed fluid
systems to ensure peak performance of the plant (FIG. 2). In fact, effective fluid
systems can significantly influence the safety, productivity and profitability
of H2 production facilities.
leaks as the system is installed. The best way to ensure proper fluid system performance is to
meticulously design, install and test the systems as the facility is being
built. During the final stages of a H2 production facility build,
engineers frequently test the crucial fluid systems using factory acceptance
testing (FAT) standards. Not only are major components inspected and qualified
at the supplier’s site, but the entire system is also often tested by pumping a
benign test fluid, such as helium or a mixture of helium and nitrogen, through
the tubes at ever-higher pressures to ensure no leaks are present.
performance is often dependent on leak-free fluid systems keeping the water flowing
at adequate levels, and leaks at the end of the process—when H2 and oxygen are captured—may lead to product
losses and potentially put employees at risk with an unexpected safety hazard. In addition, other fluids, such as
liquid alkaline solutions, may be present in the system, and it is crucial for
the reliability of the process and the safety of the operators to have these
lines leak free.
If any leaks are
detected during FAT:
techniques are the most common reasons leaks exist in fluid systems. Since all
leaks must be repaired, they create unnecessary downtime as they are fixed,
leading to lower production levels and diminished profitability. Therefore, it
is essential to eliminate leaks from the beginning so all new H2
production facilities can succeed.
To prevent leaks
during construction, it may make sense to take advantage of any installation
training suppliers can provide (FIG. 3). Proper training can help facilities reduce costs
during startup. The supplier should also be able to advise on installation best
practices so startup delays and expensive redesigning of crucial fluid
systems can be avoided. Well-trained installers are less likely to make common
mistakes that can lead to a system developing leaks at its connection points.
Keeping H2 output clean. Properly
functioning electrolyzers should produce H2 that reaches 99.9%
purity if it is to be used as a fuel source for other equipment. Keeping that
purity level depends as much on the outflow fluid systems as on the electrolyzer.
The key to
maintaining this purity in the post-electrolysis fluid systems is using the
highest-quality components possible. The electrolysis process significantly
raises temperatures and humidity near the tubing systems, which can damage
lesser-quality stainless steel components. In turn, fluid system corrosion can
lead to the contamination of the end products (FIG. 4). Damage like corrosion also poses a
potential safety hazard because corroded containers are more likely to fail.
are several methods operators can use to keep their H2 purity high,
including close monitoring of the end products using high-quality gas grab
sampling systems or via online monitoring of the quality through an effectively
designed system. In addition, the material makeup of the collection containers
is critical. To ensure containers are less likely to corrode or suffer from H2
embrittlement, components in these systems should be made of high-quality
stainless steels with higher concentrations of chromium and nickel than The
American Society for Testing and Materials (ASTM) requires (FIG. 5).
sure the facility is as productive as possible. Since the production of H2 as
a fuel is growing and evolving, no one knows for certain how to bring a new
plant online with guaranteed reliability and cost-effectiveness. Part of what
is understood by most facility operators is that adequately executed H2
production requires proper fluid transfer. For this reason, best practices learned
from many years of expertise in handling fluid systems can help reduce leaks,
safety challenges and maintenance issues in H2 production
facilities. Well-managed fuel systems at the ingress and egress of the H2
systems enable electrolyzers to be used to their full
capacity. That allows facilities to produce H2 efficiently to meet
demand (FIG. 6).
points at the design stage and leak-tightness at the installation phase prevent
potentially expensive reconfigurations during FAT and may reduce the number of
maintenance issues and related downtime that must be addressed over a system’s
lifetime. Reliable inflows and clean outflows allow the process to be as
efficient as possible, which can keep the total ownership cost manageable over
the production facility's life. Maintaining proper inflows and outflows is
another reason operators should pay close attention to the fluid systems
supporting the electrolyzer’s function.
The key to operating
a successful H2 processing facility is to choose high-quality
components and assemblies from the beginning. They should be explicitly designed
to handle H2 safely and effectively. Preparing for H2
production from the beginning will enable the facility to get up and running
more quickly, safely and productively. In this increasingly competitive green H2
market, speed and precision are critical. A reputable supplier should be able
to provide the guidance necessary to ensure the right components are in place
to make the operator’s facility a success.
are the two most prevalent electrolyzer designs? Choosing the right electrolyzer for your
facility will depend on which one makes the most sense for your application (FIG. 7). For H2 production, you have
a choice between two main designs:
Regardless of which
electrolyzer technology is used, the fluid systems that feed and collect the
finished H2 are critical to ensuring the electrolyzer always
operates at peak performance. H2T
ANA DOMINGUEZ is the Engineering Services Supervisor - Clean Energy for
Swagelok. She has worked for Swagelok for 9 yr and previously held roles as an
application and field engineer. Dominguez has been in the clean energy
engineering business for more than 13 yr and is familiar with identifying clean
energy applications and services, troubleshooting, designing for optimized
systems and innovative solutions. She is based in Zurich, Switzerland, and
earned an MS degree in chemical engineering and energy management and technology.