Sensors can detect hydrogen leaks for the safer infrastructure

Fraunhofer researchers have developed sensor systems and measuring devices that recognize leaks in hydrogen pipes and tanks. Applications for the new technology include continuous monitoring of hydrogen shipping and facilities in the chemical industry. The researchers use several sensor technologies to enable security equipment for as many scenarios of the future hydrogen economy as possible.

When it comes to the construction of the hydrogen infrastructure, the safety of pipelines, tanks and plugs is of crucial importance, since the invisible, odorless gas is high -flame and explosive. The Fraunhofer Institute for Physical Measurement Techniques IPM in Freiburg has developed sensor and measuring systems that reliably demonstrate even the slightest amount of hydrogen. This makes it quick and easy to recognize leaks of all kinds.

The research work was part of the research work of the TranshyD hydrogen flagship and the project initiated by the German Federal Ministry of Education and Research (BMBF) and Project Management Organization Project provider Jüloich (PTJ) and the project initiated by the German Federal and Research (BMBF) and the project management organization. Partners from the research sector and the industry work together in the project to develop solutions for the transport and storage of gaseous hydrogen. Dr. Carolin Pannek and the Fraunhofer IPM team were responsible for the sub -project of a safe infrastructure.

Hydrogen is used in a variety of different scenarios and applications, so that Fraunhofer researchers developed three different sensor systems.

Ultrasonic sensor with a photoacoustic effect

Light can lead to a gas vibrating and thus creating sound waves. The researchers use this photoacoustic effect for their ultrasonic sensor. In this technology, light is broadcast from a light source into the device, which creates resonant sound waves in the gas at a frequency in the ultrasound area. When hydrogen penetrates into the container through a membrane, the response that changes the sound changes. Mems microphones (microelectromechanical systems) register the sound change.

This method can be used to prove, for example, hydrogen, which can be made from tanks or pipelines. “This sensor could be used to check containers, pipelines or connections. It would also be possible to place several devices in a room such as smoke detectors and combine them into a sensor network,” explains Pannek, the project manager at Fraunhofer.

But the ultrasonic sensor can do more. It is so precise and precise that it even registers when molecules of other substances in hydrogen are available as a minimum level of contamination. Fuel cells such as the generation of electricity in trucks require high puree hydrogen. The slightest contamination could damage the sensitive membranes. The sensor can be used in these applications to check whether the hydrogen is really pure.

Laser spectrometer

An alternative to the tedious storage of hydrogen in high -pressure tanks in gaseous form or at -253 ° C in cryotans in liquid form is the use of ammonia (nh₃) as a carrier matrix. This method significantly simplifies both storage and transport. But because ammonia is very toxic, it is of crucial importance.

Fraunhofer IPM developed a laser spectrometer for the distant recognition of ammonia. It absorbs the wavelength of ammonia so that it reacts immediately. The system then shows the result on an advertisement. “Specialists can hold our compact device in hand to check pipelines or tanks from a safe distance of up to 50 meters. Mounted on a robot or drone, it can be used to check the industrial plants or fly via pipelines,” says Pannek.

Raman spectroscopy

The third measuring system builds on the principle of Raman spectroscopy. The Raman effect, named after the scientist CV Raman, is generated by interactions between light and matter. The light reflected by the matter has a different wavelength than the light emitted on the source. This means that every type of matter has its own spectroscopic “fingerprint”.

Fraunhofer IPM has years of experience in designing and configuring Raman systems. For the transhyd project, the researchers developed a filter-based Raman sensor that selectively demonstrates hydrogen in complex media. The device works with inexpensive components, including an inexpensive CMOS camera, and it is portable so that it can be used as a mobile test station to quantify hydrogen. The system is used in applications, including the production of hydrogen in the energy sector.

All sensor systems are varied so that they can be adapted for a variety of different scenarios. The Fraunhofer experts occur as needed to advise industrial customers, energy suppliers and operators of hydrogen projects on all types of problems in connection with safe use. Pannek firmly believes in the future of hydrogen: “The expansion of the hydrogen economy can now begin.”