Development of natural gas quality tracking technology: From steady-state simulation to intelligent hybrid modeling

With the creation of China’s National Integrated Pipeline Network and the transition to natural gas energy measurement, quality fluctuations caused by multisource gas mixing pose severe challenges to trade fairness and pipeline network safety. As a key technology for achieving accurate energy measurement, natural gas quality tracking has undergone a paradigm shift: from steady-state hydraulic calculations to transient composition tracking, and then to intelligent modeling paradigms that feature mechanism-data-driven collaboration. Through a systematic review of technological developments and an analysis of core algorithms, this paper highlights the core value of this technology, namely, its ability to significantly reduce reliance on online gas chromatographs, thereby providing a technical solution to promote energy measurement at Class B and C station yards. It further explores the new challenges presented by hydrogen-blended natural gas and other novel gas sources, including property calculations, numerical dissipation, and safety assessments. Ultimately, future research on this technology should focus on the deep integration of mechanistic models and artificial intelligence, propelling quality-tracking technology toward high precision, strong real-time capabilities, and wide adaptability. This review aims to provide a theoretical reference and technical support for the development of China’s self-sufficient, controllable natural gas energy measurement system.