Reclaiming of purge gas from hydrotreaters and hydrocrackers

摘要

The invention is a process to recover a high pressure hydrogen-rich gas stream from a purge gas stream taken from a hydrotreater. This purge gas stream is admixed with synthesis gas that was the original source of the hydrogen to form a gaseous mixture. This mixed gas comprising purge gas and synthesis gas is advantageously treated to remove acid gases and possibly other impurities. The mixed gas is then treated to extract a hydrogen-rich gas and a hydrogen-depleted gas using, for example, a membrane. At least a portion of the hydrogen-rich gas is then heated and compressed as necessary and is recycled to the hydrotreater.