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Abstract

A method is provided for the extraction of hellium of high purity, and high yield, with intermediate enrichment in refrigerating plants, from gases containing very low helium concentrations, by an alternating pressure adsorption process. the helium containing gas is fed cyclically in each of three adsorption stages into four adsorbers connected in parallel. First, higher hydrocarbons and other impurities are trapped in adsorbers (J, K, L, M) filled with activated charcoal in a preliminary filtering stage. Other gaseous components, for example nitrogen and/or methane are trapped in adsorbers (A, B, C, D and E, F, G, H) filled with carbon molecular sieves, in two subsequent adsorption stages. The helium is first enriched in stage (I) and then extracted in stage (II) as refined helium with a helium content of 99.9%. The gas used is preferably natural gas with a 2 to 10% helium content. The refined helium so produced can be used, for example as a blanket gas, a breathing gas for divers, a balloon gas and as a carrier gas in chromatography.

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First Claim