Abstract: A part of hydrogen from propane/isobutane dehydrogenation unit is used for the unit own use, and the rest was only used as a supplementary fuel gas, resulting in a large waste of resources. The surplus hydrogen was optimized and comprehensively utilized as a hydrogen source for 2.4 Mt/a diesel hydroupgrading unit and 1.8 Mt/a gasoline hydrorefining unit, so it could avoid the secondary shutdown caused by the shutdown of the reforming unit and improve the continuity of the unit operation. Furthermore, the high purity hydrogen purified by PSA can replace the hydrogen used in polypropylene unit which is produced by hydrogen generator station, saving a lot of electricity cost every year. In addition, the gas seal of the product compressor（REC）of the dehydrogenation unit is changed from nitrogen to hydrogen of the reforming unit, which speeds up the start-up of the unit and avoids the waste of hydrogen and propane, and improves the economic benefit of the enterprise.

Key words: propane, isobutane, dehydrogenation unit, hydrogen, product compressor, dry gas seal