FCEV-Independent Hydrogen Sampling Methodology and Purity Analysis with Ion-Molecule-Reaction Mass Spectrometry

Kurzfassung

Contaminations in hydrogen have a strong impact on the long-term stability and thereby performance of proton exchange membrane (PEM) based fuel cells for the application in fuel cell electric vehicles (FCEV). While these influences have been intensively studied, particularly the purity of the hydrogen provided at public hydrogen refueling stations (HRS) is rarely analyzed. We have taken samples of hydrogen at HRS with a specially designed mobile refueling module enabling the FCEV-independent sampling at 70 MPa. With a method specifically developed in this study, we seek to ensure that other sources of contamination can be excluded during the probe sampling. With analysis techniques able to determine concentrations of contaminants down to the parts per billion (ppb) level the hydrogen samples are investigated in the laboratory. While single routes of contamination, such as the synthesis route, have been individually studied in detail elsewhere, the provision of hydrogen with different storage processes, as well as transport and compression at the HRS are considered in these investigations as a holistic system. In the first approach series, HRS supplied by on-site electrolysis showed high purity as expected, in general, but also noteworthy contamination above the threshold of the international standard ISO 14687 in the form of water (19.23 ± 4.24 ppm), carbon dioxide (2.90 ± 0.09 ppm), and nitrogen (761.68 ± 22.72 ppm). With this study, it can be stated whether the dispensed hydrogen meets the high-quality requirements of fuel cells for mobile applications.