Fuel cell electric vehicles provide the potential to decarbonise road transport, create new economic opportunities, diversify national energy supply, and significantly reduce the environmental impacts of road transport. A potential issue, however, is that the catalyst used at the fuel cell cathode is susceptible to degradation by impurities, especially sulphur-containing compounds. A recent European Directive (2014/94/EU) stipulates that, from November 2017, all hydrogen produced for use with fuel cell electric vehicles must comply with the purity requirements as specified in ISO 14687; this includes reactive and toxic chemicals such as sulphur-containing compounds and ammonia, thus presenting difficult measurement challenges. Without the available reference materials and analytical infrastructure, hydrogen refuelling stations will not be able to demonstrate compliance to the ISO 14687 specifications. The National Physical Laboratory provides world leading, accredited purity measurements to allow hydrogen refuelling stations to evidence compliance to ISO 14687. This presentation will provide an overview of the state-of-the-art methods that have been developed, including a novel method for measuring total sulphur compounds and a hydrogen impurity enrichment device.
Sam Bartlett is a Research Scientist in the Gas and Particle Metrology Group at the National Physical Laboratory. He is currently working on the high accuracy preparation and analysis of odorant gas mixtures to support industry and research by enabling accurate odorisation of energy gases, such as natural gas and hydrogen. Sam uses gas chromatography with detection techniques such as flame ionization, sulphur chemiluminescence and mass spectroscopy to fulfil these analytical requirements. He is involved with the development of measurement and analytical techniques to help further the capabilities of NPL’s hydrogen purity laboratory, specialising in the preparation of traceable reference gas standards of reactive components at ambient levels to fulfil quality requirements specified in ISO 14687. Sam is also responsible for development and maintenance of NPL’s novel dynamic dilution facility, which uses mass-flow controllers in conjunction with mass-flow elements in order to prepare traceable reference gas standards at ambient levels to fulfil EU Air Quality Directives.