In a natural gas feed stream consisting of methane and other hydrocarbons (CH4), nitrogen (N2), and helium (He), helium’s very simple atomic structure allows it to selectively permeate and enrich in concentration much faster than the other components. When a natural gas stream containing helium is fed at pressure to a hollow fiber membrane, helium is selectively concentrated in the permeate stream, leaving a helium-depleted methane-rich stream as the residue stream. The helium-enriched permeate stream can then be compressed, re-injected for storage, or further purified in a downstream pressure swing adsorption (PSA).
ALaS offers three hollow-fiber membranes for helium recovery: type 5200, 5240 and G5SHP. For a given helium recovery application, the membrane type selected would be based on feed gas properties, pressure, volumetric flow rate, and other factors. In all cases, the type membranes can be applied to a natural gas feed stream containing < 1 mol% He to concentrate He in the permeate stream at ≥ 5 mol% with ≥ 99 mol% He recovery. Multiple-stages of membranes can provide a final helium-enriched product stream with > 50 mol% He.
ALaS' patented helium recovery process can be used to recover helium from a natural gas feed stream and concentrate the helium in the permeate stream for re-injection and long-term storage, or for further purification by other means such as liquefaction or PSA. The patented process scheme maximizes the enrichment and recovery of helium.