SoA of measuring devices installed in NG transmission and distribution networks

Deliverable D1.1 aims to design the state of the art of measuring devices in natural gas transmission and distribution networks. Transporting green hydrogen into existing gas assets requires carefully assessing its effect on the existing components. Since several projects have already been completed or have planned research activities to answer still-existing technical questions, the THOTH2 project focuses on the existing measuring devices. Specifically, the focus of the project regards the identification of the existing gaps in normative standards and the suggestions for solutions to cover them (if any). To contribute the hydrogen readiness of the existing gas transport and distribution infrastructures, new methodologies and protocols have to be developed to perform validated tests for metering devices. Suggestions on the need to change the standards or develop new ones will be based on the results of these experimental tests. Despite the simplicity of the methodological approach, it would be very critical when applying it to measuring devices. Several technologies are available in the market to measure gas properties. Furthermore, the operators can select more than one configuration based on the expected field conditions. Since limited resources are available, testing all the possible configurations would be impossible. Prioritization is required. Task 1.1 aims to collect all the information to provide a clear overview of the measuring devices installed in the existing gas assets. Specifically, this document includes the state of the art of measuring devices installed in gas assets. Different technologies are available to measure gas parameters. For example, turbine, rotary piston, ultrasonic, diaphragm, thermal mass, orifice, and Coriolis meters are available to measure flow rate. These technologies differ not only for the operating principle but also for the material used, the size available on the market, and the effect that different conditions could have on the metrological performances like, for example, overload conditions, flow rate pulsations, leakages through the clearance and pressure drops. Furthermore, different maintenance activities are usually expected, resulting in different operative costs throughout the lifetime. To date, turbine, rotary piston gas, and ultrasonic meters are used for fiscal gas metering in transmission networks. Specifically, based on the data collected, turbine gas meters are the most installed technologies for medium to high flow rate, followed by rotary piston and ultrasonic (for high flow rate). Few cases of use of Coriolis meters have been found. Regarding distribution, a different situation results. Despite the fact that few answers have been received to date, and only from Italy, it appears that diaphragm gas meters are the prevailing technology installed, even if a greater penetration is expected for thermal mass meters. THOTH2 also includes other measurements like gas quality by chromatographs, pressure and temperature, and trace water dew point. Regarding temperature, it was assumed that since the sensor is not in contact with the fluid but is protected by the thermowell, it can be assumed that no problem would arise. However, further investigation should be performed to investigate if any effect of hydrogen on response time exists. Regarding pressure measurement, many models are commercially available, but attention should be given to the effect of hydrogen on the material with which the fluid is in contact. Specifically, identifying critical materials that can be affected by hydrogen among those available in commercial products should be the next step to identifying the products to be tested. Gas chromatographs are also present in different models and configurations in the existing networks. Usually, different columns are used based on the specific analysis to be performed. Even if the range of the concentration allowed for each molecule is usually known for each model, more details about the configuration of each gas chromatograph are needed to complete the analysis and check the capability to handle hydrogen. Only some models of trace water sensors have been identified in the investigated networks. Specifically, impedance sensors result in the most implemented devices. Other devices are also typically used in the networks. Electronic Volume Converters and Flow Computers convert measurements into standardized gas volumes for fiscal purposes. The main issues to be investigated are the implemented algorithms and their capability to consider hydrogen. The main algorithms are AGA8, SGERG, and AGA-NX19, and the Operators can check the hydrogen limits. The main issue is that many different models are installed in gas transmission and distribution networks. Furthermore, based on the conclusion about pressure and temperature sensors, the potential effects of hydrogen on the metrological performances of those devices that have these sensors integrated have to be carefully assessed not to overcome the limits on errors provided by the standards. Last, leak detection is essential to detect fugitive emissions to the atmosphere and to minimize the risk of failures or accidents . To date, many devices are supplied to the technicians on the field to verify the presence of hazardous substances. Since different sensors can be implemented in the same devices to measure different quantities, attention should be given in Task 2.1 to selecting those sensors that, on the current knowledge, appear to be most critical when being in contact with hydrogen.可交付成果D1.1旨在确立天然气输配管网中测量设备的当前技术水平（state of the art）。将绿色氢能输送至现有天然气资产中，需对其给现有组件带来的影响开展严谨评估。鉴于已有多个项目完成或正在规划相关研究活动以解答尚存的技术疑问，THOTH2项目聚焦于现有测量设备。具体而言，本项目的研究重点在于识别规范标准中存在的空白，并提出针对性的解决方案建议（若存在）。为推动现有天然气输配基础设施实现氢能适配性，需开发新的方法与规程，以完成对计量设备的验证性测试。关于修订现有标准或制定新标准的建议，将基于这些实验测试的结果得出。尽管该方法论路径看似简单，但将其应用于测量设备时却极具挑战性。市场上可用于测量气体特性的技术多种多样。此外，运维人员可根据预期的现场工况选择多种配置方案。由于可用资源有限，对所有可能的配置进行测试并不现实，因此需要进行优先级排序。任务1.1旨在收集所有相关信息，以清晰呈现现有天然气资产中安装的测量设备概况。本文件具体涵盖了天然气资产中安装的测量设备的当前技术水平。可用于测量气体参数的技术种类繁多，例如涡轮流量计、旋转活塞流量计、超声流量计、膜式流量计、热式质量流量计、孔板流量计以及科里奥利流量计（Coriolis meters）等，均可用于流量测量。这些技术不仅工作原理各异，其所使用的材质、市场上可获取的尺寸规格，以及不同工况对计量性能的影响（例如过载工况、流量脉动、间隙泄漏及压降等）也存在差异。此外，通常需要开展不同的维护工作，这将导致设备全生命周期内的运营成本有所不同。截至目前，涡轮流量计、旋转活塞式气体流量计及超声流量计是输气管网中用于贸易结算的主流计量技术。具体而言，根据收集到的数据，涡轮气体流量计是中高流量场景下安装量最多的技术，其次为旋转活塞流量计与超声流量计（用于高流量场景）。科里奥利流量计的应用案例较少。关于配气管网，情况则有所不同。尽管目前仅收到来自意大利的少量反馈数据，但现有数据显示膜式燃气表仍是主流安装技术，尽管热式质量流量计的渗透率预计将有所提升。THOTH2项目还涵盖其他测量内容，例如通过色谱仪进行的气体品质分析、压力与温度测量，以及痕量水露点检测。关于温度测量，假设由于传感器未直接接触流体，而是通过热电偶套管（thermowell）进行防护，因此不会出现相关问题。但仍需开展进一步研究，以验证氢气是否会对传感器响应时间产生影响。关于压力测量，市场上有多种商用型号可供选择，但需重点关注氢气对流体接触材料的影响。具体而言，下一步需在商用产品的可用材质中识别出可能受氢气影响的关键材料，以确定需要测试的产品。燃气色谱仪在现有管网中也存在多种型号与配置。通常，需根据具体的分析任务选择不同的色谱柱。尽管每种型号的各组分浓度允许范围通常已明确，但仍需获取更多关于每台燃气色谱仪配置的详细信息，以完成分析并验证其处理氢气的能力。在被调研的管网中，仅识别出少量型号的痕量水传感器。其中，阻抗式传感器是应用最广泛的设备。管网中通常还会使用其他设备：电子体积转换器（Electronic Volume Converters）与流量计算机（Flow Computers）可将测量数据转换为用于贸易结算的标准化气体体积。需重点研究的核心问题包括其采用的算法以及是否能够考虑氢气的影响。主流算法包括AGA8、SGERG及AGA-NX19，运维人员可据此核查氢气的限值。当前面临的主要问题是，天然气输配管网中安装了多种不同型号的此类设备。此外，结合前述关于压力与温度传感器的结论，对于集成了这些传感器的设备，需仔细评估氢气对其计量性能的潜在影响，以确保不超出标准规定的误差限值。泄漏检测对于检测向大气排放的无组织排放、最小化故障或事故风险至关重要。目前，市场上有多种设备可供现场技术人员检测危险物质的存在。由于同一设备中可集成多种传感器以测量不同参数，因此在任务2.1中需重点关注：基于当前认知，筛选出在与氢气接触时表现出最显著临界性的传感器。