[ instrumentation ]
• Electrochemical method : These sensors consist of an electrode that reacts to hydrogen .
• Catalytic : Here , the combustion energy is measured at the surface of the sensor , and a concentration is determined from this .
• Optical : The hydrogen molecule interacts at a specific wavelength .
• Thermal : Here , the specific thermal conductivity of the gas is determined .
However , most hydrogen sensors are impractically large , show signs of aging that destroy calibration over time , and are usually extremely expensive to purchase and maintain . These are just three of the challenges that need to be addressed , especially since there is a great ambition to bring about an energy turnaround , also and especially with the help of hydrogen . What is needed is an optimized measurement technology that can measure precisely and reliably while being costeffective and ideally comes in a plug-and-play solution for easy handling . The specifications of technology providers are therefore well filled and are being further expanded by the legislators through additional regulations and requirements .
Companies that are highly specialized in gas analysis , with a focus on hydrogen measurement and close involvement of scientific experts , have a clear advantage here , as they are fully oriented to the specific needs of the hydrogen industry .
In order to meet customer requirements without compromise , attention must be paid , for example , to the special effect of hydrogen on many material properties ( e . g ., as a result of hydrogen diffusion ), since the functional elements of the sensors must not irreversibly change their physical properties and thus the sensor parameters , such as sensitivity , as a result of contact with hydrogen . Degradation of the sensors due to exposure to hydrogen must therefore be ruled out .
Central examples of the measurement challenges can be found in electrolysers . This is because moisture in the process gas can falsify measurements , which is why cross-sensitivity compensation or gas dehumidification is required . Reaction times ( t90 ) in the process should also be kept as low as possible . Some manufacturers expect a measurement time of 100 milliseconds .
Fine microsensors in stainless steel dress
Hydrogen Tech World | Issue 11 | August 2023 31