Objective Hydrogen-blended natural gas pipeline is regarded as one of the important ways to transport hydrogen energy in large scale, low cost and long distance.In order to obtain high purity hydrogen, hydrogen-blended natural gas needs to be separated at the terminal.At present, the common hydrogen separation methods are not directly applicable to the separation of hydrogen-blended natural gas with low hydrogen concentration.

Methods This paper introduces the principle, process parameters, advantages and disadvantages of the common hydrogen separation technology.Combined with the characteristics of hydrogen-blended natural gas, the coupling process route of "membrane separation+pressure swing adsorption" is determined, and the economic analysis is made on the separation process scheme of hydrogen-blended natural gas with hydrogen blending ratio of 10 mol%, 15 mol% and 20 mol%.The separation cost of each separation scheme is specified.

Results The comprehensive separation cost of 10% hydrogen blending ratio is 0.846 7 yuan/m³ hydrogen, the comprehensive separation cost of 15% hydrogen blending ratio is 0.519 7 yuan/m³ hydrogen, and the comprehensive separation cost of 20% hydrogen blending ratio is 0.382 6 yuan/m³ hydrogen.

Conclusions The separation cost of hydrogen-blended natural gas with low concentration is high, and its large-scale application still faces economic constraints and challenges.