Hydrogen, a highly volatile and flammable gas, poses specific safety risks, especially during production, transport and storage. An efficient safety concept based on a thorough risk analysis and hazard assessment is therefore essential. This analysis should include the definition of the protection goal, the identification of hazards as well as their analysis and evaluation. Based on this, protective measures can be defined to minimise the risk in hydrogen technology.
Some of the specific hazards in handling hydrogen are:
– Leakage: Due to its small molecular size, hydrogen can easily leak from compressed gas lines and containers. Regular inspections, the right choice of materials and stationary gas warning technology are crucial here.
– Odourlessness and colourlessness: Since hydrogen cannot be perceived with human senses, effective gas warning technology is required.
– Explosiveness: Hydrogen is extremely flammable, and even a spark can be enough to trigger an explosion. Stationary gas warning systems are of great importance here.
– Invisible flame: Hydrogen burns with a flame that is invisible in daylight. Flame detectors specifically designed for hydrogen and its combustion product H2O2 are therefore necessary.
The Most Important Sensor Technologies
To achieve the highest possible safety level, a combination of different sensor technologies should be considered. Each of these technologies has specific properties that make them particularly suitable for certain applications and environments.
Catalytic sensors work on the basis of catalytic combustion. When combustible gases such as hydrogen come into contact with the active element of the sensor, an oxidation reaction takes place that generates heat. This heat generation is measured and converted into a gas concentration. Catalytic sensors are particularly effective at detecting gases below their lower explosive limit and offer a fast response time.
Electrochemical sensors use a chemical reaction to detect gases. They consist of an electrolyte solution and at least two electrodes. When the gas to be detected comes into contact with the sensor surface, a redox reaction takes place that generates an electric current. This current is proportional to the gas concentration and is measured and interpreted by the sensor electronics. Electrochemical sensors are particularly useful for selective measurements of hydrogen at ppm concentration levels and can also be used to monitor indoor atmospheric oxygen levels.
Ultrasonic detectors detect leaks through the ultrasound generated by escaping gas. This technology is particularly effective in monitoring pressurised gas containers or pipes. Ultrasonic detectors register the sound of the escaping gas and can thus detect even the smallest leaks, regardless of wind and weather influences. Another advantage of this technology is that loud ambient noise in the audible range does not influence the measurement signal, as it is specifically designed for ultrasonic frequencies.
By combining these sensor technologies, a comprehensive and reliable security network can be created that ensures both continuous monitoring and fast response times in hydrogen technology.