Search

EP-4735811-A1 - CRYOGENIC NEON PURIFICATION SYSTEM AND METHOD

EP4735811A1EP 4735811 A1EP4735811 A1EP 4735811A1EP-4735811-A1

Abstract

A feed gas including neon, nitrogen, and helium is cooled in a heat exchange system to a first temperature to produce a two-phase mixture that is introduced into a first phase separator and separated into a nitrogen-rich liquid and a first gaseous crude neon stream. The pressure is reduced in at least a portion of the nitrogen-rich liquid, which is vaporized in the heat exchange system to generate a portion of the refrigeration therein. The first gaseous crude neon stream is introduced into a first adsorber that removes impurities such as nitrogen. The gaseous crude neon stream is further cooled to a second temperature. A portion of the cooling duty may come from the heat exchange system and another portion may come from a cryocooler to produce a two-phase stream. The two-phase stream is separated in a second phase separator into a crude helium vapor stream and a crude neon liquid stream with the latter being introduced into a distillation column to produce a vent stream containing a helium impurity and a pure liquid neon product. The pure liquid neon product is vaporized in the heat exchange system to generate refrigeration and produce the pure gaseous neon product.

Inventors

  • BROSTOW, ADAM, ADRIAN
  • FELDMAN, Steven, Lawrence

Assignees

  • Chart Energy & Chemicals, Inc.

Dates

Publication Date
20260506
Application Date
20240628

Claims (20)

  1. 1. A method of purifying a mixture comprising neon, nitrogen, and helium comprising the steps of: (a) cooling the feed gas comprising neon, nitrogen, and helium in a heat exchange system to the first temperature to produce a two-phase mixture; (b) optionally reducing in pressure and then introducing the two-phase mixture into the first phase separator to be separated into a nitrogen-rich liquid and the first gaseous crude neon stream; (c) reducing in pressure at least a portion of the nitrogen-rich liquid and vaporing it in the heat exchange system to generate a portion of the refrigeration for the process; (d) introducing the first gaseous crude neon stream into the first adsorber that removes impurities such as nitrogen; (e) further cooling the gaseous crude neon stream to the second temperature in such a manner that at least a portion of the cooling duty comes from the heat exchange system to produce a two-phase stream; (f) separating the two-phase stream in a second phase separator into a crude helium vapor stream and a crude neon liquid stream; (g) optionally reducing in pressure the crude neon liquid stream and then introducing it into a distillation column to produce a vent stream containing a helium impurity and a pure liquid neon product; (h) optionally reducing in pressure of the pure liquid neon product and then vaporizing it in the heat exchange system to generate refrigeration and produce the pure gaseous neon product.
  2. 2. The method of claim 1 where an additional portion of the cooling duty in step (e) comes from another refrigeration device.
  3. 3. The method of claim 2 where the cryocooler cold head is placed inside of the second phase separator.
  4. 4. The method of claim 2 comprising multiple cryocoolers present in series and in parallel.
  5. 5. The method of claim 1 where a crude helium vapor stream of step (f) is purified in the second adsorber to remove neon.
  6. 6. The method of claim 1 where the nitrogen-rich liquid in step (c) is supplemented by an additional liquid nitrogen import.
  7. 7. The method of claim 1 where the feed gas is compressed before cooling.
  8. 8. A system for purifying neon comprising: a feed stream line configured to receive a gas mixture, wherein the gas mixture comprises neon, nitrogen, and helium; at first heat exchanger configured to cool and/or heat the streams of the system; a first separator in fluid communication with the feed stream line, and wherein the separator is configured to separate the mixed gas mixture to a crude neon vapor stream and a nitrogen-rich liquid stream; a first adsorber in fluid communication with the first separator, wherein the adsorber receives the crude neon vapor stream from the first separator; a second separator in fluid communication with the first adsorber, wherein the second separator is configured to separate a stream from the first adsorber into a crude helium vapor stream and a crude neon liquid stream; and a distillation column in fluid communication with the second separator, wherein the distillation column receives the crude neon liquid stream and is configured to purify the crude neon liquid stream to a pure neon liquid product.
  9. 9. The system of claim 8, wherein the nitrogen-rich liquid stream is used to refrigerate the system.
  10. 10. The system of either one of claims 8 and 9, further comprising an imported liquid nitrogen stream.
  11. 11. The system of any one of claims 8-10, further comprising a second heat exchanger.
  12. 12. The system of any one of claims 8-11, wherein the second separator is associated with a cryocooler.
  13. 13. The system of claim 12, wherein the cryocooler is placed inside the second separator.
  14. 14. The system of either one of claims 12 and 13, wherein the cryocooler is a Gifford- McMahon cryocooler.
  15. 15. The system of any one of claims 8-14, comprising a second adsorber in fluid communication with the second separator, wherein the second adsorber receives the crude helium vapor from the second separator.
  16. 16. A method of purifying neon comprising the steps of cooling a gas mixture comprising neon, nitrogen, and helium in a heat exchange system to a first temperature; separating the mixture in a first separator into a nitrogen-rich liquid stream and a crude neon vapor stream; purifying the crude neon vapor stream in a first adsorber; cooling the crude neon stream to a second temperature; separating the crude neon stream in a second separator into a crude helium vapor stream and a crude neon liquid stream; and purifying the crude neon liquid stream in a distillation column to a purified neon product stream.
  17. 17. The method of claim 16 further comprising the steps of reducing the pressure of the nitrogen-rich liquid stream and vaporizing it in the heat exchange system to generate a portion of the refrigeration for the system.
  18. 18. The method of either one of claims 16 and 17 further comprising the step of introducing an imported liquid nitrogen stream to the heat exchange system to generate a portion of the refrigeration for the system.
  19. 19. The method of any one of claims 16-18, wherein the first adsorber is configured to remove nitrogen.
  20. 20. The method of claim 16-19 further comprising the step of cooling the second two- phase stream with a cryocooler associated with the second separator.

Description

CRYOGENIC NEON PURIFICATION SYSTEM AND METHOD IN THE RECEIVING OFFICE OF THE UNITED STATES PATENT AND TRADEMARK OFFICE PCT INTERNATIONAL PATENT APPLICATION INVENTORS: Adam Adrian Brostow Steven Lawrence Feldman TITLE: CRYOGENIC NEON PURIFICATION SYSTEM AND METHOD ATTORNEY: R. Blake Johnston Cook Alex Ltd. 200 West Adams St. Suite 2004 Chicago, Illinois 60606 CRYOGENIC NEON PURIFICATION SYSTEM AND METHOD CLAIM OF PRIORITY [0001] This application claims the benefit of U.S. Provisional Application No. 63/510,927, filed June 29, 2023, the contents of which are hereby incorporated by reference. FIELD OF THE DISCLOSURE [0002] The present disclosure relates generally to purifying neon and, more particularly, to a cryogenic system for and method of purifying a feed including neon, nitrogen, and helium. BACKGROUND [0003] Neon is a rare gas in short supply. It is over 50 times more expensive than helium. It has several applications such as neon-helium lasers, as a critical component in kryptonargon lasers used to make semiconductor chips, and in cryogenic refrigeration. Neon is present in the air in small quantities. Most of the neon is produced by fractional cryogenic distillation of air. A conventional cryogenic air separation unit (ASU) may only produce a small stream enriched in neon, typically comprising neon, nitrogen, and helium. Additional steps are required to further concentrate and purify it. [0004] A 2010 paper, “Purification and Liquefaction of Neon Using a Helium Refrigeration Cycle,” (S. Boeck, “Purification and Liquefaction of Neon Using a Helium Refrigeration Cycle,” AIP Conference Proceedings 1218, 272-277 (2010)) describes the purification and liquefaction of a mixture of neon, nitrogen, and helium. The mixed feed is cooled to cryogenic temperatures with nitrogen and helium separated by vapor-liquid equilibrium. The product is liquid neon 99.99% pure. The refrigeration for the process is partially supplied by isentropic (work) expansion of gaseous helium, the so-called reverse-Brayton cycle. One of the limitations of such a process is the availability and reliability of the machinery required such as helium expanders (turboexpanders or reciprocating expansion engines) and the helium recycle compressor, especially on a small scale. For example, U.S. Patent Publication 2014/0202174, discloses an example of a Gifford-McMahon cryocooler that may be used in such a process. [0005] Therefore, there is a need for improved devices, systems, and methods to produce pure neon. SUMMARY OF THE DISCLOSURE [0006] There are several aspects of the present subject matter which may be embodied separately or together in the methods, devices and systems described and claimed below. These aspects may be employed alone or in combination with other aspects of the subject matter described herein, and the description of these aspects together is not intended to preclude the use of these aspects separately or the claiming of such aspects separately or in different combinations as set forth in the claims appended hereto. [0007] In one aspect, a method of purifying a mixture including neon, nitrogen, and helium is provided. The method includes cooling the feed gas including neon, nitrogen, and helium in a heat exchange system to a first temperature to produce a two-phase mixture, introducing the two-phase mixture into a first phase separator to be separated into a nitrogen-rich liquid and a first gaseous crude neon stream, and reducing in pressure at least a portion of the nitrogen-rich liquid and vaporizing it in the heat exchange system to generate a portion of the refrigeration for the method. The method further includes introducing the first gaseous crude neon stream into a first adsorber that removes impurities such as nitrogen, further cooling the gaseous crude neon stream to a second temperature in such a manner that at least a portion of the cooling duty may come from the heat exchange system and another portion from a cryocooler to produce a two-phase stream, and separating the two-phase stream in a second phase separator into a crude helium vapor stream and a crude neon liquid stream. The method also includes optionally reducing in pressure the crude neon liquid stream and then introducing it into a distillation column to produce a vent stream containing a helium impurity and a pure liquid neon product and optionally reducing in pressure of the pure liquid neon product and then vaporizing it in the heat exchange system to generate refrigeration and produce the pure gaseous neon product. [0008] In another aspect, a system for purifying neon is provided. The system includes a feed stream line configured to receive a gas mixture, wherein the gas mixture includes neon, nitrogen, and helium and a first heat exchanger configured to cool and/or heat the streams of the system. The system also includes a first separator in fluid communication with the feed stream line and wherein the separator is configured to separate the