While there is various methods to measure the consumption of hydrogen, there is also numerous challenges and potential troubles linked to these methods that can be encountered and have to be taken in account :
Hydrogen is a highly permeable gas, and even small leaks in the system can significantly affect consumption measurements. It’s crucial to ensure the integrity of the system and properly seal any potential leakage points to avoid inaccuracies in consumption measurements. That’s why the valves and piping materials need to be re-examined. Plus is, as natural gases, hydrogen is odorless. In order to detect leakage points, a distinct odor is usually added to natural gases. The difference with hydrogen is that the addition of odorant has to be studied to be sure it doesn’t affect composition nor properties.
Impurities or contaminants in the hydrogen gas stream can interfere with measurement accuracy. For instance, if the hydrogen contains traces of other gases, it may affect the readings of flow meters or gas chromatography analysis. It’s important to use appropriate purification techniques and regularly maintain the gas stream to minimize impurities. This point is also challenging in that, depending on the expected level of measurement accuracy, few other points must be considered (way and cost of analysis, lead time and sample size, method validation depending on the country standards).
Changes in temperature and pressure can affect the volume and density of hydrogen gas, leading to inaccuracies in measurement. It’s important to consider the operating conditions and the positioning of the meter as the temperature of the measured fluid can change. That influence has to be investigated to ensure the flow measurement is accurate and that’s why secondary instrumentation such as temperature and pressure measurements have to be integrated to the metering architecture.
Accurate measurement requires properly calibrated instruments. Over time, the accuracy of flow meters, mass flow meters, or gas chromatographs may drift, leading to incorrect measurements. Regular calibration and maintenance of measurement equipment are essential to ensure reliable and accurate readings. Plus, the meters need to be calibrated with hydrogen in ISO 17025 accredited calibration facilities.
When using gas chromatography or other sampling techniques, it’s crucial to ensure that the samples collected are representative of the overall gas stream. Improper sampling techniques or inadequate sampling frequency can introduce errors and affect the accuracy of consumption measurements.
Linked articles : [https://www.sciencedirect.com/science/article/pii/S0360319919312194] [https://www.npl.co.uk/energy-transition/hydrogen-industry] [https://www.marcogaz.org/wp-content/uploads/2021/07/ODOR-Hydrogen-and-odorisation.pdf] [https://h21.green/news/hydrogen-to-smell-like-natural-gas-for-the-first-time/] [https://www.alderley.com/2023/01/11/hydrogen-challenges-how-do-we-measure-it-properly/] [https://www.sciencedirect.com/science/article/abs/pii/S0360319923010844]