Objective Hydrogen-blended natural gas transportation offers a viable pathway for large-scale hydrogen transportation. The separation and purification of hydrogen significantly influence the quality and economic efficiency of hydrogen for terminal use. However, traditional separation and purification technologies face challenges, including low separation efficiency, high energy consumption, and insufficient adaptability, due to the low hydrogen content, complex composition, and wide pressure range of hydrogen-blended natural gas, as well as stringent quality requirements for separated hydrogen and natural gas.

Methods Through literature research, the research progress on hydrogen separation and purification technologies for hydrogen-blended natural gas was systematically reviewed. The characteristics and requirements for the separation and purification of hydrogen-blended natural gas were summarized. The development status and characteristics of pressure swing adsorption, membrane separation, electrochemical hydrogen pumps, and integrated technologies were analyzed, and key research directions for practical applications were prospected.

Results Under economic constraints, pressure swing adsorption faces performance limitations and challenges with natural gas recompression. It is essential to develop efficient, low-cost adsorbents and optimize processes to explore pathways for direct hydrogen adsorption and adsorption heat utilization. Membrane separation technology offers a simple process, high recovery rates, and strong scalability. Enhancing its performance, service life, and cost-effectiveness will significantly advance its application in hydrogen separation and purification from hydrogen-blended natural gas. Focus should be placed on developing materials and equipment for pretreatment, improving separation efficiency and stability through material modification and support processing, and accelerating large-scale deployment. Electrochemical hydrogen pumps, with advantages such as high efficiency and simultaneous compression, show integration potential but face issues like high energy costs, hydrothermal management challenges, and impurity poisoning. Future efforts should aim to enhance proton membrane conductivity and resistance to impurity permeability, develop poison-resistant catalysts, optimize flow fields and hydrothermal control strategies, and further reduce equipment costs. Integrated technologies consider purity, recovery rate, and cost, making them ideal for hydrogen separation and purification from hydrogen-blended natural gas. Continued optimization of multi-scenario process flows, investigation of synergistic impurity treatment methods, and exploration of new integrated processes are essential.

Conclusion Currently, research on hydrogen separation and purification technologies for hydrogen-blended natural gas remains largely theoretical or at the experimental stage. Practical testing on natural gas hydrogen-blending platforms or projects should be prioritized to optimize processes, advance equipment development in real-world scenarios, enhance technical feasibility, economic efficiency, maturity, and adaptability, and facilitate the large-scale deployment of hydrogen energy.