Preparation of Gas Standards for Quality Assurance of Hydrogen Fuel

This study has developed traceable standards for evaluating impurities in hydrogen fuel according to ISO 14687. Impurities in raw H2, including sub mmol/mol levels of CO, CO2, and CH4, were analyzed using multiple detectors while avoiding contamination. The gravimetric standards prepared included mixtures of the following nominal concentrations: 1, 2, 3e5, 8e11, 17e23, and 47e65 mmol/mol for CO2, CH4 and CO, O2, N2, Ar, and He, respectively. The expanded uncertainty ranges were 0.8% for Ar, N2, and He, 1% for CH4 and CO, and 2% for CO2 and O2. These standards were stable, while that for CO varied by only 0.5% during a time span of three years. The prepared standards are useful for evaluating the compliance of H2 fuel in service stations with ISO 14687 quality requirements.