Abstract: In view of the problem that a large amount of hydrogen-rich gas in the fully hydrogenation refinery enters the fuel gas pipeline network as low value fuel, a cascade recovery and utilization scheme of hydrogen-rich gas with different concentrations was proposed: the hydrogen-containing gas with low concentration was initially separated through the membrane recovery unit (phase II).The product hydrogen(phase II), dry gas from light hydrocarbon recovery unit and isomerization unit, and flare recovery gas were used as the raw materials of the membrane recovery unit(phase I) for secondary separation.The product hydrogen(phase I), the continuous reformer hydrogen, low pressure separation gas from residue hydrotreater, gas oil hydrocracker and diesel hydrogenation unit were thirdly separated by PSA to produce high purity hydrogen with 99.54% of hydrogen. The commercial application results showed that for a refinery with a processing capacity of 10.0 Mt/a, the hydrogen recovery was 13.1 kt/a, the natural gas consumption was reduced by 21.2 kt/a, the carbon emission was reduced by 150 kt/a, and the processing cost was reduced by 4.62 Yuan/t.

Key words: hydrogen, PSA, membrane recovery, cascade recovery, carbon emission