Development and evaluation of a novel analyser for ISO14687 hydrogen purity analysis

Standards ISO14687 and EN17124 set stringent limits for numerous gaseous impurities and particulates that may damage the fuel cell system in a hydrogen vehicle, as it is highly sensitive to the presence of even very low levels of impurities. However, performing the whole set of analyses is both technically challenging and time-consuming for any laboratory and will require a combination of several analytical techniques or instruments. In this study, we discussed the selection of analytical techniques for hydrogen purity testing in order to optimize the CAPEX (capital expenditure) and OPEX (operational expenditure), while ensuring the quality of the results and the compliance of the analytical methods with ISO21087. Among the individual impurities to be analysed in ISO14687, spectroscopy techniques are suitable for ammonia, carbon dioxide, carbon monoxide, formaldehyde, formic acid, oxygen and water. Spectroscopy techniques are even suitable for some impurities belonging to the three total species such as hydrogen sulphide, hydrogen chloride and methane. However, helium and argon, which are monoatomic, do not exhibit response in the infrared region. Therefore, any spectroscopic analysis method must be completed by another method in order to simultaneously analyse all individual gaseous impurities from ISO14687. In this study, we constructed and demonstrated the feasibility of an instrument composed of a gas chromatograph having three columns (two packed columns and a PLOT (Porous Layer Open Tubular) column and two detectors (FID and TCD) coupled in parallel to two OFCEAS instruments using reference gas mixtures. Finally, we also proposed an extended configuration that will allow performing the whole set of analyses for gaseous species from ISO14687.