Reliable fuel-cell operation
Functionally integrated system solutions for hydrogen supply and water separation – Collaboration with Proton Motor Fuel Cell GmbH
Bürkert’s fluidics components have consistently demonstrated their reliability in many hydrogen applications to date. Turnkey system solutions for anode supply and water separation were developed for the fuel cells produced by Proton Motor Fuel Cell GmbH. One constructive way to address the climate crisis and reduce carbon footprint is the use of green hydrogen. Fuel cell systems are both an environmentally-friendly and sustainable energy-supply solution in stationary and mobile applications alike. Fluidics components play an important part in ensuring that they can function reliably and safely. Bürkert’s functionally integrated system solutions, featuring advanced valves and sensors, guarantee precise hydrogen dosing, secure hydrogen shut-off, and accurate water separation within the anode circuit of the fuel cells. These compact solutions are designed for seamless integration with fuel cell stacks.
Precise and safe hydrogen dosing
With the HyStack® 400, Proton Motor Fuel Cell GmbH has developed compact fuel cell modules that deliver power ranging from 21.3 to 49.7 kW, making them suitable for a wide range of applications. In the HyShelter®, the scalable fuel cell modules are arranged into a hybrid, turnkey container solution.
The scalable HyStack® 400 fuel cell covers power ranges from 21.3 to 49.7 kW, making it suitable for a wide range of applications.
Thanks to its extensive experience across all types of hydrogen applications, ranging from generation to distribution and utilization, Bürkert proved to be a competent partner for the development of the desired fluidic solution. Indeed, in earlier projects, other fuel cell manufacturers had also had positive experiences with Bürkert valve technology. The Bürkert product portfolio includes a wide range of fluidic components, with materials tailored to the specific requirements of these applications, thus providing the basis for diverse system solutions. In the application in question, compact blocks were developed for anode supply and water separation. These blocks were designed to be mounted directly on the media adapter plate of the stacks using fluidic fittings, thus keeping installation space requirements to a minimum. “The media adapter plates, produced by an external supplier using 3D printing, serve as more than just a mechanical interface. They are in fact a multifunctional component that monitors both the pressure and temperature of each line, and in conjunction with the overarching system, ensures proper temperature regulation,” explains Robert Baustädter. This means that the fuel cells are quickly operational even at sub-zero temperatures.
“We were looking for a tried-and-tested, turnkey system solution for our module hydrogen supply and water separation that would meet our fluidic requirements and provide a tailored interface to the fuel cell stack module.” Such systems are critical for the operation of the fuel cell, as they regulate the supply of hydrogen at the anode inlet as well as being responsible for safety shut-off. At the anode outlet, they must also ensure proper gas purging as well as water separation.
Proportional valves in the anode block
In the anode block, a proportional valve handles the hydrogen supply, while a shut-off valve is responsible for the safety shut-off of the hydrogen. An integrated pressure sensor monitors the set-point pressure. A pressure switch was additionally installed as a redundant safety component. The safety shut-off valve (Type 6440) – a servo-assisted piston valve – has already proven its reliability in numerous hydrogen applications. The stopper and the core guide tube are welded together to increase pressure resistance and security against leaks. The particular shape and surface quality of the housing allow maximal flow values. The coils are encased with an epoxy that is highly resistant to chemicals. The second valve (Type 6020) – a direct-acting proportional valve – takes care of pressure control for the hydrogen. With its integrated shut-off function, it also provides a tight seal. It is already being deployed in many hydrogen and gas applications. Suitable cartridge and flange connections, as well as solenoids with automotive plugs with IP6K9K protection rating, are available for use in fuel-cell systems.
For anode supply and water separation, compact system blocks were developed that are designed to be mounted directly on the media adapter plate of the stacks using fluidic fittings.
Water and hydrogen separation
In fuel cell systems, the hydrogen introduced into the anode is never fully consumed. Through the so-called recirculation loop, unused hydrogen is not wasted but is instead fed back into the fuel cell stack. At the anode outlet, the water separator, with its two integrated valves, performs two key functions: it facilitates the flushing process of the fuel cell system and removes the water produced by the chemical reaction within the fuel cell stack. In the two direct-acting Type 7011 plunger valves, the stopper and core guide tube are welded together to increase pressure resistance and security against leaks. The seal materials are tailored to the specific application, as the valves must not only work precisely and reliably, but must also be appropriate for the specific application range. In the case of hydrogen, for example, it must be ensured that the materials used do not become brittle, and where deionised water is concerned, that the materials do not corrode.
“Since the fluid system solution for anode supply and water separation has proven itself admirably in the HyStack® 400, we will be continuing to work closely with Bürkert in the future. With the HyStack® 200, which is currently in development with outputs ranging from 4 to 11 kW, the same fluid systems will basically be used, but with smaller valve nominal diameters. Here, too, we will be benefitting hugely from the know-how of the fluidics experts.”