Saarland University researchers have developed a new sensor system to monitor fuel quality at hydrogen fueling stations.
The infrared measuring cell provides continuous in-situ monitoring and can be installed inside the station itself.
Impurities such as sulfur-containing compounds, ammonia or hydrocarbons can all contaminate hydrogen during the production process, during transportation to the hydrogen station or during the refilling process.
This in turn affects fuel quality, making driving a lot less pleasurable.
‘Contaminants can actually poison the fuel cell,’ explains sensor expert Professor Andreas Schütze, who along with his team developed the new monitoring system.
Even low levels of impurities can damage the fuel cell membranes. As a result, the fuel cell produces less electricity, power output is reduced and the vehicle travels shorter distances.
In a worst case scenario, contaminants irreversibly damage the fuel cell, bringing the car to an abrupt halt.
To stop things ever getting that far, Schütze and his team have been working with research partners Fraunhofer ISE and Hydac Electronic GmbH, to ensure the fuel cell is fed only with high purity hydrogen.
Up until now, the purity of the hydrogen was determined by analyzing samples in a laboratory.
It remains a challenge to measure at the required level of precision and cope with the conditions under which the sensor system needs to operate, intones Schütze.
Take for instance the refueling process; it uses hydrogen pressures of 700 to 900 bar and lasts less than three minutes.
The team has therefore developed an infrared measuring cell that can measure reliably and accurately under these extreme conditions.
The measuring cell for the odorless gas H2 is installed inside the hydrogen fueling station and the hydrogen fuel flows through a small tube.
“We illuminate the gas passing through the tube with light from an infrared source and we collect the light passing out on the opposite side of the tube,” explains Schütze.
“If there has been a change in the chemical composition of the gas, the infrared spectrum will change accordingly. This allows us to detect the presence of unwanted additives or contaminants.”
Image and content: Oliver Dietze/Saarland University