Research Status of Ultrasonic Measurement Adaptability of Hydrogen Blended Natural Gas

Hydrogen pipeline transportation is a critical path for the current energy transition, but the blending of hydrogen into existing natural gas pipeline infrastructures faces technical challenges. This article focuses on the adaptability of ultrasonic flow meters in hydrogen blending natural gas, and explores the influence of hydrogen characteristics on measurement accuracy, material hydrogen embrittlement effect, and energy measurement. The small molecular weight and low density of hydrogen gas result in significant differences in its sound velocity and flow field characteristics compared to natural gas, which poses a challenge to the stable operation of ultrasonic flow meters. Different signal processing methodologies or algorithms and manufacturer equipment perform differently. In terms of materials, the hydrogen embrittlement effect may cause pipeline and equipment failure, but existing theories such as HEDE and HELP still cannot fully explain its mechanism and require further experimental verification. In addition, the decrease in heating value of hydrogen blending natural gas requires energy measurement to shift from volumetric measurement to energy measurement, but the relevant technical standards are not yet perfect. Research has pointed out that current experiments are mostly limited to small-scale and simulation, and systematic studies need to be conducted based on the properties of hydrogen doped gases, flow field distribution, and signal attenuation to promote the safe application and standardized construction of hydrogen energy pipelines.