COMBINED MEMBRANE AND PRESSURE SWING ADSORPTION METHOD FOR RECOVERY OF HELIUM

摘要

The invention relates to a method of obtaining helium from a process gas,wherein atleast the following steps are executed: feeding a helium-containing processgas havinga pressure of less than 15 bar to a first membrane separation stage (2) havinga firstmembrane (4) which is more readily permeable for helium than for at least onefurthercomponent present in the process gas; guiding a first retentate stream to asecondmembrane separation stage (3) having a second membrane (5) which is morereadilypermeable for helium than for at least one further component present in theprocessgas; separating helium from a first helium-containing permeate stream by meansofpressure swing adsorption to produce a helium-containing product stream; andrecycling a second helium-containing permeate stream to the first membraneseparation stage (2), and recycling a purge gas from the pressure swingadsorption tothe first membrane separation stage (2).