Abstract: A method is provided for extracting helium from a relatively helium poor gas mixture through a pressure swing adsorption process which adhieves an enriched product gas containing over 50% helium. The gas mixture to be enriched is fed cyclically to four adsorber vessels ranged in parallel which successively pass through a pressure build-up, an adsorptive and a pressure relief phase, with pressure build-up and relief being in part brought about by pressure compensation with any one of the other adsorbers. The pressure-build up and relief phases include a series of three and four, respectively, steps involving alternating pressure levels. As a preliminary treatment, the process may include an initial step wherein the unenriched gas mixture is first fed through a series of pre-filters filled with activated carbon for removing higher hydrocarbons.

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.