Extraction of helium-enriched fraction from a liquified natural gas product, comprises e.g. separating a fraction containing methane, nitrogen and helium to a helium-rich gas fraction and a methane and nitrogen containing liquid fraction

摘要

Procedure for the extraction of helium-enriched fraction from a fraction (I) containing methane, nitrogen and helium (1) comprises: e.g. (a) relaxing and separating the fraction (I) to a helium-rich, methane and nitrogen containing gas fraction (II) and a liquid fraction (III) containing methane and nitrogen (7); (b) relaxing and separating the liquid fraction (III) to a nitrogen-rich gas fraction (8) and a methane-rich liquid fraction (17); (c) cooling and partially condensing the gas fraction (II); (d) separating the partially condensed gas fraction (II) to a helium-enriched gas fraction. Procedure for the extraction of helium-enriched fraction from a fraction (I) containing methane, nitrogen and helium (1), e.g. a liquified natural gas product, comprises: (a) relaxing and separating the fraction (I) to a helium-rich, methane and nitrogen containing gas fraction (II) and a liquid fraction (III) containing methane and nitrogen (7); (b) relaxing and separating the liquid fraction (III) to a nitrogen-rich gas fraction (8) and a methane-rich liquid fraction (17); (c) cooling and partially condensing the gas fraction (II); (d) separating the partially condensed gas fraction (II) to a helium-enriched gas fraction and a nitrogen/methane-rich liquid fraction; and (e) relaxing and evaporating the nitrogen/methane-rich liquid fraction in the indirect heat exchange with the partially condensed fraction (II).