Session chair: Tracey Jacksier, Air Liquide (US)
The session “Accelerating the hydrogen economy” will take place on Wednesday 19 June 2019 with the following lectures:
D.1 – KEYNOTE: Towards sustainable hydrogen society – The future outlook of fuel cell vehicles in Toyota and global hydrogen quality requirements by Ward Storms, Toyota Motors Europe (BE)
This keynote will explain in the first part Toyota’s vision on the hydrogen society and mobility. In the second, more detailed part, the keynote will focus on the remaining challenges in hydrogen quality from technical and normative point of view.
D.2 – How ensure the quality of hydrogen for fuel cell vehicles? by Martine Carré, Air Liquide (FR)
Stringent quality control of hydrogen gas, during production, transportation, storage, and utilization, is key for the development of fuel cell technology for vehicles. With the aim of assuring uniformity in the worldwide quality of the hydrogen product, the International Organization for Standardization has published several standards related to this topic. First, ISO 14687 gives the technical specifications of the hydrogen fuel, indicating the maximum content of certain non-hydrogen gases. Second, ISO 19880-8 documents how the quality of the hydrogen fuel for PEM fuel cell road vehicles can be assured. Third, ISO 21087 describes the requirements for the validation of the analytical methods used to measure the level of contaminants in the gaseous hydrogen fuel. The European Committee of Standardization published also EN 17124, which combines, in the same document, the technical specifications and the quality assurance in agreement with the ISO ones. Considering these standards, it is necessary to develop a global approach to assure the quality at acceptable cost. This paper presents hydrogen quality control approaches and analytical measurements. The sampling protocol plays also a key role for ensuring the integrity of the sample to control. Some recommendations on sampling system are given. Then, the validation of the analytical methods used to control the impurities is described according to the requirement of ISO 21087.
D.3 – Quality assurance of fuel cell hydrogen: from car and hydrogen refuelling station to the analytical laboratory by Thomas Bacquart, NPL (GB)
Hydrogen refuelling stations (HRS) are becoming a reality in Europe (82 HRS in 2018). Automotive manufacturers are rolling out their hydrogen fuel cell electric vehicles (FCEV) like Toyota Mirai or Mercedes GLC F-cell. A main concern of using hydrogen in FCEV is the detrimental effect that contaminants, such as sulphur compounds, can have to the vehicle performance. ISO 14687 sets limits for 13 parameters in hydrogen which are a real analytical challenge due to extremely low quantities (nmol/mol) or the nature of the compounds (e.g. halogenated). The second challenge is to obtain a representative sample (sampling and stability until analysis). The National Physical Laboratory (NPL), based in the UK, has successfully developed analytical methods and obtained ISO/IEC 17025 testing accreditation to measure accurately hydrogen contaminants as specified in ISO 14687. The state-of-the-art of gas standard preparation will be presented including contaminant stability in hydrogen. Some insights on contaminant stability over time in sampling vessel will be discussed (i.e. O2, H2S or C4Cl4F6). Method validation and quality system will be presented as a strategy to ensure quality for hydrogen quality measurement. Method validation according to ISO 21087 will highlight NPL analytical capability at extremely low concentration (i.e. 4 nmol/mol of total sulphur). Hydrogen sampling will be presented with existing sampling system (i.e. Linde Qualitizer) and new design. The results will highlight the impact of contaminant from sampling (i.e. H2O or air). NPL demonstrates the possibility to measure accurately impurities in hydrogen at low amount fraction and the availability of reference gas standards in hydrogen. NPL hydrogen laboratory will present a strategy to achieve ISO/IEC 17025 accreditation and compliance to ISO 21087. Hydrogen sampling will be discussed with emphasis on future evolution to ensure representative sampling.
D.4 – Performances of available analytical methods to control the purity of hydrogen according to ISO 14687-2 by Frederique Haloua, LNE (FR)
Hydrogen purity dispensed at hydrogen refuelling points should comply with the technical specifications included in ISO 14687-2 “Hydrogen fuel – Specification – Part 2: Proton exchange membrane (PEM) fuel cell”. However, for routine laboratory/analysis, performing the whole set of analyses is currently extremely challenging due to the low detection limits to reach and the number of analyses required. In the EMPIR (European Metrology Programme for Innovation and Research) project 15NRM03 “Metrology for sustainable hydrogen energy applications”, we have reviewed the current performances of the analytical methods that are proposed so far for the 13 gaseous species to analyse (including availability of validation data; limit of detection, repeatability, precision, robustness). We have also gathered information on methods using dedicated multi-component analyzers (as OFCEAS, CRDS, FTIR). The review will provide indications on analytical methods suitability and cost for the implementation of hydrogen quality laboratory. Another challenge when performing hydrogen purity analysis according to ISO 14687-2 is the parameters that cover a large number of species, the so-called total species. In the project, we have developed speciation methods for the total species (sulphur, halogenated, hydrocarbons) at amount fraction lower than the ISO 14687-2 threshold values. The application of the speciation methods will enable the measurement of the actual contaminants present in hydrogen for FCEV, which possibly could lead to suggestions for the replacement of “total species” with the actual contaminants. This lecture gives an overview of the results that have been obtained.
D.5 – Trace level analysis of reactive ISO 14687-2 impurities in hydrogen gas by Heleen Meuzelaar, VSL (NL)
Hydrogen fuel cell vehicles can play a major role in the challenge of drastically reducing greenhouse gas emission by the decarbonisation of the transportation sector. The global uptake of low-emission hydrogen-powered vehicles by the automotive industry strongly depends on the supply of high-quality hydrogen fuel at refuelling stations, as even trace amounts of impurities are known to have adverse effects on the performance and lifetime of the fuel cell. To reduce the risks of such effects, the specification ISO 14687-2 has been issued to set hydrogen purity requirements at refuelling stations. However, due to a lack of traceable methods and reference standards, the industry cannot provide evidence by traceable measurement results that the hydrogen meets the requirements for a number of the impurities specified, particularly for reactive contaminants. To facilitate traceable hydrogen purity analysis in support of ISO 14687-2, VSL has developed a versatile system for accurately generating and measuring amount fractions of several reactive impurities in hydrogen at the threshold levels. Measurement standards for hydrogen fluoride, hydrogen chloride, ammonia, formic acid and formaldehyde in hydrogen were dynamically generated at μmol mol-1 and nmol mol-1 levels based on the permeation method as described in ISO 6145-10. The mass loss of the permeation tubes was recorded using a passivated and calibrated magnetic suspension balance that performs continuous accurate mass measurements. Generated calibration gas mixtures were consecutively measured using different advanced spectroscopic techniques. An estimated relative expanded uncertainty of ±20% at the ISO 14687-2 threshold has been achieved for most of the impurities considered. The presentation covers both the calibration gas mixture generation and spectroscopic analysis systems and discusses the results obtained.
D.6 – Sampling for trace analytes by Thomas Huddle, EnDet (GB)
The preservation of samples containing trace analytes is a serious challenge facing existing and emerging gas technologies. Sampling them correctly is even more challenging, be it for on-line or lab-based analysis. Many new gas technologies have a reduced tolerance for contaminants both for their financial viability and environmental impact. This has driven increasingly stringent thresholds for contaminants in gas processes, stressing the importance of accurate trace analyte measurement and monitoring more than ever. The design, configuration and procedures associated with many traditional sampling apparatuses can and will imperceptibly affect the concentration of trace analytes in samples through their journey from extraction to analysis. Moreover trace analytes retained by the apparatus during each sample are often liable to compromise subsequent samples, leading to a worsening issue between system maintenance procedures. This presentation considers several major aspects of sampling and details the mechanisms by which they can affect the concentration of numerous critical trace analytes in newer applications such as biomethane processes, hydrogen for mobility, critical processing of low carbon energy gases and processing of shale gas. Alternative innovative methods of sample extraction and collection are proposed which tackle each of these issues in turn and work synergistically, permitting truly representative samples to be transported from the point of sampling to the analyser, whether analysis is conducted on-line or at a remote site. The issues with trace analyte sampling described find commonality across a range of existing, emerging and likely future gas-based processes, and thus addressing these problems with a holistic solution will allow greater research focus on the key aspects of the technologies.
D.7 – Towards a novel primary method for the production and certification of trace water vapour in hydrogen reference gas mixtures by Paul Carroll, NPL (GB)
Fuel cell hydrogen vehicle use is critical to achieve Europe’s carbon-neutral target by 2050. One of the regulated contaminants in ISO 14687 is water vapour (maximum permitted level of 5 μmol mol-1) as water can contaminate hydrogen from electrolysis. Reliable measurement of water vapour is needed by the hydrogen industry (for both quality laboratories and on-site analysers). Calibration of analysers can be performed using cylinders containing gas mixtures certified for their water content to give confidence to measurements of hydrogen purity. The production and certification of static gas mixtures containing water vapour amount fractions certified by gravimetric methods has proved challenging at values below 10 μmol·mol-1. When cylinders are prepared gravimetrically, water vapour content in the delivered gas is commonly lower than expected from gravimetric measurements. This is believed to be due to the adhesion of water molecules to the inner surfaces of the cylinders used. It is therefore common practice to use a reference instrument (e.g. water vapour spectrometer) to certify the water content of a gravimetrically prepared water vapour mixture cylinder. The NPL multi-gas, multi-pressure primary standard humidity generator has been used to produce binary gas mixtures in cylinders with a calculated reference value of 5 μmol mol-1 water vapour content, initially with air as the matrix gas. Subsequent measurements of the water content of the cylinder gas using a hygrometer showed agreement with the reference value to within 0,1 μmol mol-1 at this level.