Combined membrane-pressure swing adsorption method for recovery of helium

Patent metadata

Field	Value
Publication number	US-10207928-B2
Application number	US-201515527821-A
Country	US
Kind code	B2
Filing date	Dec 7, 2015
Priority date	Dec 17, 2014
Publication date	Feb 19, 2019
Grant date	Feb 19, 2019

Abstract

A method of obtaining helium from a process gas. The process gas is at a pressure less than 15 bar to a first membrane separation stage having a first membrane more readily permeable for helium than for at least one other component in the process gas. A first retentate stream is fed to a second membrane separation stage having a second membrane more readily permeable for helium than for at least one other component in the process gas. Helium is separated from a first helium-containing permeate stream using a pressure swing adsorption to obtain a helium-containing product stream. A second helium-containing permeate stream is recycled to the first membrane separation stage. A purge gas from the pressure swing adsorption is also recycled to the first membrane separation stage.

First claim

The invention claimed is:

1. A method for obtaining helium from a helium-containing process gas, said method comprising:
a) feeding a helium-containing process gas having a pressure of less than 15 bar to a compression,
b) feeding the process gas that leaves the compression to a prepurifying unit in which troublesome components are removed;
c) guiding the process gas from the troublesome components have been removed to a first membrane separation stage having a first membrane which is more readily permeable for helium than for at least one further component present in the process gas;
d) guiding a first retentate stream that has not passed through the first membrane to a second membrane separation stage having a second membrane which is more readily permeable for helium than for at least one further component present in the process gas;
e) separating helium from a first helium-containing permeate stream that has passed through the first membrane by means of pressure swing adsorption to produce a helium-containing product stream; and
f) recycling a second helium-containing permeate stream that has passed through the second membrane to the first membrane separation stage, and recycling a purge gas from the pressure swing adsorption to the first membrane separation stage.

2. The method according to claim 1 , wherein a temperature swing adsorption is conducted in the prepurifying unit.

3. The method according to claim 1 , wherein the process gas is a manufacturing offgas from a manufacturing process for production of an electronic and/or semiconductor element, the troublesome components to be removed in said prepurification including at least one of the following components: H 2 , a hydrocarbon, H 2 O, CO 2 , a sulphur compound, a silane, a phosphine, arsine, a halogenated hydrocarbon, a fluorine gas, and a metal hydride.

4. The method according to claim 2 , wherein a second retentate stream that has not passed through the second membrane is used for regeneration of an adsorber used in the temperature swing adsorption.

5. The method according to claim 1 , wherein a second retentate stream that has not passed through the second membrane is expanded to perform work.

6. The method according to claim 1 , wherein the helium content of the first permeate stream is not less than 25% by volume, and/or in that the helium content of the product stream is not less than 95% by volume.

7. The method according to claim 1 , wherein the helium-containing process gas has a helium content of more than 0.1% by volume.

8. The method according to claim 1 , wherein the helium-containing process gas is fed to the compression in a) at a pressure of less than 10 bar.

9. The method according to claim 1 , wherein a reaction is conducted in the prepurifying unit.

10. The method according to claim 1 , wherein a thermal oxidation is conducted in the prepurifying unit.

11. The method according to claim 1 , wherein a second retentate stream that has not passed through the second membrane is expanded to electrical energy.

12. The method according to claim 1 , wherein the helium content of the first permeate stream is not less than 25% by volume, and/or in that the helium content of the product stream is not less than 99% by volume.

13. The method according to claim 1 , wherein the helium-containing process gas has a helium content of more than 0.5% by volume.

14. The method according to claim 1 , wherein the membrane materials used for the membranes of the first and second membrane separation stages are selected from polyimides, polysulphones and polyaramids.

15. The method according to claim 1 , wherein the operating temperatures in the first and second membrane separation stages are within the range from 0° C. to 120° C.

16. The method according to claim 2 , wherein the operating temperature in the temperature swing adsorption is within the range from 0° C. to 120° C.

17. The method according to claim 16 , wherein the operating temperatures in the first and second membrane separation stages are within the range from 0° C. to 120° C.

18. The method according to claim 2 , wherein the inlet streams into the two membrane separation stages or into the temperature swing adsorption have a pressure in the range from 10 bar to 80 bar.

19. The method according to claim 1 , wherein the inlet stream into the pressure swing adsorption has a pressure in the range from 5 bar to 20 bar.

20. The method according to claim 1 , wherein the second helium-containing permeate stream and the purge gas from the pressure swing adsorption are recycled to a point upstream of the compression.

Assignees

• Linde Ag

Inventors

• Voss Christian
• Tota Akos
• Bauer Martin
• Jennewein Frank

Classifications

• B01D53/047

  Pressure swing adsorption · CPC title

• C01B23/0094

  Combined chemical and physical processing · CPC title

• B01D51/10

  Conditioning the gas to be cleaned · CPC title

• B01D53/226

  in serial connexion · CPC title

• B01D53/229

  Integrated processes (Diffusion and at least one other process, e.g. adsorption, absorption) · CPC title