New ways of measuring atmospheric hydrogen: paving the way for hydrogen leak quantification

该项目的目的是开发和演示如何使用大气氢的移动的测量来定位和量化氢向大气的逃逸排放。随着我们向净零排放迈进，人们提出了增加氢作为燃料的建议，迫切需要量化将释放到大气中的氢的数量。氢气很容易泄漏，例如通过管道系统中的接头和在车辆加油期间。这对气候和空气质量都有影响。氢气是一种间接的温室气体，因为大气中增加的氢气量会与大气中的羟基发生反应并减少其含量，从而增加甲烷的寿命。大气中氢排放量的增加还将导致对流层臭氧的形成（另一种温室气体，对空气质量有害），并减少平流层臭氧和水蒸气。我们需要量化有多少氢气将被排放到大气中，并确定哪里可能发生泄漏，以便在能源生产中广泛使用氢气之前实施更好的基础设施设计。采用氢气是否会导致正或负的净辐射强迫取决于氢气泄漏率以及相关的碳排放变化和氢气生产方法。近年来，激光光谱学已被证明是非常有用的移动的检测甲烷泄漏的车辆，飞机和无人机。最近的研究量化了甲烷泄漏率，并显示了可以减少排放的地方，为最近的全球甲烷承诺提供了科学依据。氢的类似研究是必要的，但目前没有合适的高精度和便携式仪器。在本项目中，将建造一个进气系统，以压缩和干燥环境空气，然后通过一个商业上可用的仪器进行测量，该仪器设计用于工业中测量干燥压缩空气中的氢气。该仪器在催化剂上氧化氢气，然后使用所得水蒸气的光谱分析来量化氢气的摩尔分数。最初，该仪器将在实验室中运行，并将测量结果与用于大气氢测量的已建立（但不是便携式）气相色谱技术进行比较。据设想，该仪器将作为安装在皇家霍洛威公司移动的温室气体实验车上的移动的测量系统投入使用。还将设计和进行实验，以测量氢气和甲烷在管道中混合时的泄漏率，这是英国正在提出和测试的。将公布关于量化氢泄漏的测量技术的建议。最终，有助于减少向大气泄漏的氢的逃逸性排放的技术的开发将改善向氢基能源生产过渡的气候和环境效益。

The aim of this project is to develop and demonstrate how mobile measurements of atmospheric hydrogen can be used to locate and quantify fugitive emissions of hydrogen to the atmosphere. With proposals to increase use of hydrogen as a fuel as we move towards net-zero, there is an urgent need to quantify the amount of hydrogen that will be released to the atmosphere. Hydrogen leaks easily, e.g. through joints in pipework and during vehicle fuelling. There are climate and air quality consequences of this. Hydrogen is an indirect greenhouse gas because increased amounts of hydrogen in the atmosphere will react with and reduce the amount of hydroxyl in the atmosphere, hence increasing the lifetime of methane. Increased emissions of hydrogen in the atmosphere would also lead to formation of ozone in the troposphere (another greenhouse gas and damaging to air quality) and reduce stratospheric ozone and water vapour. We need to quantify how much hydrogen will be emitted to the atmosphere, and identify where leaks are likely to occur so that better infrastructure design is implemented ahead of widespread hydrogen use in energy production. Whether or not adoption of hydrogen will lead to a positive or negative net radiative forcing depends on the hydrogen leakage rate as well as on the associated changes in carbon emissions and the method of hydrogen production. Laser spectroscopy has proved to be very useful in recent years for mobile detection of methane leaks by vehicle, aircraft and drone. Recent studies have quantified methane leak rates and shown where emissions can be cut, providing the science behind the recent Global Methane Pledge. Similar studies for hydrogen are necessary, but a suitable high precision and portable instrument is not currently available. In this project an inlet system will be built to compress and dry ambient air which will then be measured by a commercially available instrument that is designed for use in industry for measuring hydrogen in dry compressed air. The instrument oxidises hydrogen over a catalyst and then uses spectroscopic analysis of the resultant water vapour to quantify the hydrogen mole fraction. Initially the instrument will be run in the laboratory and measurements will be compared with established (but not portable) gas chromatography techniques for atmospheric hydrogen measurements. It is envisaged that this instrument will then be operational as a mobile measurement system installed in Royal Holloway's mobile greenhouse gas laboratory vehicle. Experiments will also be designed and carried out to measure leak rates of hydrogen and methane when they are blended in pipelines as is being proposed and tested in the UK. Recommendations on measurement techniques to quantify hydrogen leakage will be published. Ultimately the development of techniques to locate fugitive emissions of hydrogen that will help reduce leaks to the atmosphere will improve the climate and environment benefit of a transition to hydrogen based energy production.