초록 ▼

A process for the separation/recovery of gases is described where the desired component to be separated from the gaseous mixture is present in low/very low molar amount and/or low/moderate pressure, the process comprising contacting the gaseous mixture with a separation membrane unit containing high

A process for the separation/recovery of gases is described where the desired component to be separated from the gaseous mixture is present in low/very low molar amount and/or low/moderate pressure, the process comprising contacting the gaseous mixture with a separation membrane unit containing high permeability/medium selectivity membranes which separate the feed stream into a permeate stream, enriched in the desired component and at a lower pressure and a retentate stream lean in the desired component and at a higher pressure. The retentate stream is made to convey its pressure to the permeate stream which then is directed to an adsorption PSA unit for further purification of the permeate stream so that the effluent stream from the PSA unit which contains the purified component has a purity of up to 99.90%. The process is useful for separating hydrogen from refinery off gases such as FCC gases and can also be applied to other gases such as helium and any other valuable gases present in gaseous streams in low to very low molar contents and low to moderate pressures.

대표청구항 ▼

[ We claim:] [1.] A process for the separation/recovery of gases with the aid of a membrane/PSA system from a stream where the desired component is present at low molar concentration and/or low pressure, which consists essentially of the following steps:compressing and directing the compressed feed

[ We claim:] [1.] A process for the separation/recovery of gases with the aid of a membrane/PSA system from a stream where the desired component is present at low molar concentration and/or low pressure, which consists essentially of the following steps:compressing and directing the compressed feed stream containing the desired component at moderate temperature and pressure to a membrane unit of high permeability and medium selectivity whereby are separated a low pressure stream enriched in the desired component--the permeate stream--and a lean stream or retentate, enriched in non-desired component(s) at pressure close to that of the feed;saving energy by conveying the pressure inventory from the retentate stream to the permeate stream so as to elevate the permeate pressure;directing the permeate stream at elevated pressure to a PSA system which selectively adsorbs non-desired components, for purification of the desired component;recovering the desired component from the PSA system;desorbing and discarding the purge stream containing the non-desired components from the PSA system.