Helium extraction from natural gas
AssigneeAir Products and Chemicals, Inc.
InventorsVincent White, Paul Higginbotham, Jason Michael Ploeger
Life of this patent
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Abstract
A helium-containing stream is recovered from a natural gas feed using a membrane followed by multiple distillation steps. Refrigeration is provided by expanding a bottoms liquid with a higher nitrogen content than the feed, achieving a lower temperature in the process. The helium-enriched vapor is then purified and the helium-containing waste stream is recycled to maximize recovery and reduce the number of compressors needed. The helium-depleted natural gas stream can be returned at pressure for utilization or transportation.
Claims10
A process for recovering helium from a natural gas feed comprising methane, nitrogen, and helium, said process comprising:
- introducing said natural gas feed to a membrane separation system to produce a helium-enriched permeate stream and a helium-depleted non-permeate stream;
- compressing said helium-enriched permeate stream in a permeate compressor to produce a compressed permeate stream;
- cooling said compressed permeate stream, or a stream derived from said compressed permeate stream, to produce a cooled permeate stream which is at least partially condensed;
- separating said cooled permeate stream in a first distillation column system to produce a helium-enriched overhead vapor and a first helium-depleted bottoms liquid;
- cooling said helium-enriched overhead vapor to produce a cooled overhead stream which is at least partially condensed;
- separating said cooled overhead stream in a second distillation column system to produce a crude helium vapor and a second helium-depleted bottoms liquid;
- and expanding at least a portion of the second helium depleted bottoms liquid to produce a low-temperature refrigerant;
- wherein the cooling duty for cooling the helium-enriched overhead vapor is provided at least in part by indirect heat exchange with said low-temperature refrigerant;
- warming at least a portion of said second helium-depleted bottoms liquid to produce a first return stream;
- combining said first return stream with said first helium-depleted bottoms liquid to produce a second return stream;
- and compressing and combining said second return stream with said low-temperature refrigerant and said helium-depleted non-permeate stream to produce a helium-depleted natural gas product.
Dependencies are inferred from the claim text.