Abstract: In view of the configuration of hydrogen purification system and the properties of exhaust gas of a newly built 20 Mt/a refinery of an enterprise, the scheme of process optimization based on the original hydrogen recovery process was determined. The implementation effect of the optimization scheme was verified by detailed material flow, hydrogen production, exhaust emissions to the fuel gas network, compressor handling capacity, membrane separation module handling capacity, and benefit and investment accounting. The results showed that the recovery of the hydrogen from the desorption gas of No.5 PSA(pressure swing adsorption) unit by membrane separation and PSA coupling process increased 9 880.53 m³/h, and the annual economic benefit of the refinery was about 25.498 6 million Yuan. However, the scheme of building a new hydrogen PSA unit can increase hydrogen production by 14 351 m³/h, but the new PSA cannot be centrally arranged in the hydrogen purification area because of its large footprint, as a result, the timeliness of operation and accident treatment is reduced.

Key words: refinery, exhaust gas, hydrogen, membrane separation, pressure swing adsorption