Method for recovering helium

A method for recovering a helium product fraction from a nitrogen- and helium-containing feed fraction, wherein

• the nitrogen- and helium-containing feed fraction is partially condensed and separated into a first helium-enriched fraction and a first nitrogen-enriched fraction,
• the first helium-enriched fraction is subjected to an adsorptive cleaning process and the helium-enriched fraction recovered therefrom represents the helium product fraction,
• the first nitrogen-enriched fraction is separated into a second helium-enriched fraction and a second nitrogen-enriched fraction, and
• the second helium-enriched fraction is preheated against the nitrogen- and helium-containing feed fraction to be partially condensed, condensed and admixed to the nitrogen- and helium-containing feed fraction to be partially condensed,
• characterized, in that
• the separation of the first nitrogen-enriched fraction into a second helium-enriched fraction and a second nitrogen-enriched fraction is implemented in a separation column, to which the first nitrogen-enriched fraction is supplied as return flow,
• a sub-flow of the second nitrogen-enriched fraction evaporates and the separation column is supplied as stripping gas,
• at least a sub-flow of the second nitrogen-enriched fraction is evaporated against the nitrogen- and helium-containing feed fraction to be partially condensed under a pressure of less than 5 bar,
• a third nitrogen-enriched fraction is removed from the separation column,
• wherein the stripping gas quantity is set such that the third nitrogen-enriched fraction contains at least 30% of the nitrogen contained in the first nitrogen-enriched fraction, and
• the third nitrogen-enriched fraction serves at least partially to cool the nitrogen- and helium-containing feed fraction to be partially condensed.