Recovery of krypton and xenon from liquid oxygen

Patent metadata

Field	Value
Publication number	US-11460246-B2
Application number	US-201916718978-A
Country	US
Kind code	B2
Filing date	Dec 18, 2019
Priority date	Dec 18, 2019
Publication date	Oct 4, 2022
Grant date	Oct 4, 2022

Abstract

Xenon and/or krypton is separated from a liquid oxygen stream comprising oxygen and xenon and/or krypton in a process comprising providing at least a portion of the liquid oxygen stream as a reflux liquid to the top of a rare gas recovery column operated at a pressure of between 5 to 25 bara, vaporizing a reboiler liquid in the reboiling zone in the bottom of the rare gas recovery column to produce a mixture of a rising vapor and a xenon and/or krypton-enriched liquid stream; and contacting the rising vapor with the reflux liquid in at least one distillation zone of the column to effect stripping xenon and/or krypton from the rising vapor to the reflux liquid. The process provides a recovery of xenon of greater than 90% and a krypton recovery of 15% to 90%.

First claim

What is claimed is:

1. A process for the recovery of xenon and/or krypton from a liquid oxygen stream comprising oxygen and xenon and/or krypton, said process comprising:
providing a rare gas recovery system comprising a rare gas recovery column having a top, a bottom, at least one distillation zone, and a reboiling zone comprising a reboiler;
providing a liquid oxygen feed comprising oxygen and xenon and/or krypton;
providing a first portion of the liquid oxygen feed to the top of rare gas recovery column to form a reflux liquid;
providing a low-pressure liquid oxygen stream;
vaporizing a reboiler liquid in the reboiling zone to produce a mixture of a rising vapor and a xenon and/or krypton-enriched liquid stream;
contacting the rising vapor with the reflux liquid in the at least one distillation zone to effect stripping xenon and/or krypton from the rising vapor to the reflux liquid to produce the reboiler liquid;
removing the rising vapor from the top of the rare gas recovery column forming a xenon and/or krypton-lean gaseous oxygen stream;
removing the xenon and/or krypton-enriched liquid stream from the bottom of the rare gas recovery column;
passing the xenon and/or krypton-lean gaseous oxygen stream directly through a cold compressor forming a cold compressed oxygen stream;
passing the cold compressed oxygen stream through the reboiler producing condensed liquid oxygen by indirect heat exchange with the reboiler liquid in the reboiling zone; and
removing the condensed liquid oxygen from the rare gas recovery system as xenon and/or krypton-lean liquid oxygen;
compressing the low-pressure liquid oxygen stream in a pump, to a pressure greater than the operating pressure of the rare gas recovery column, forming a compressed liquid oxygen stream;
warming the compressed liquid oxygen stream by indirect heat exchange in a desubcooler to form the liquid oxygen feed; and
passing the condensed liquid oxygen to the desubcooler, and cooling by indirect heat exchange with the compressed liquid oxygen stream, to produce a subcooled xenon and/or krypton-lean liquid oxygen;
wherein the rare gas recovery column is operated at an operating pressure of between 5 to 25 bara.

2. The process according to claim 1 , further comprising providing a second portion of the liquid oxygen feed to the rare gas recovery column at a position between the at least one distillation zone and the reboiling zone.

3. The process according to claim 1 , wherein the rare gas recovery column is operated at an operating pressure of between 10 and 20 bara.

4. The process according to claim 1 , further comprising reducing the pressure of the subcooled xenon and/or krypton-lean liquid oxygen in a valve and passing the subcooled xenon and/or krypton-lean liquid oxygen to a phase separator forming a low-pressure return liquid.

5. The process according to claim 1 , further comprising providing a high-pressure liquid oxygen stream, reducing the pressure of the high-pressure liquid oxygen stream in a valve to a pressure greater than the operating pressure of the rare gas recovery column forming a compressed liquid oxygen stream, warming the compressed liquid oxygen stream by indirect heat exchange in a desubcooler to form the liquid oxygen feed; and passing the condensed liquid oxygen to the desubcooler and cooling by indirect heat exchange with the compressed liquid oxygen stream to produce a subcooled xenon and/or krypton-lean liquid oxygen.

6. The process according to claim 5 , further comprising reducing the pressure of subcooled xenon and/or krypton-lean liquid oxygen in a valve, and passing the subcooled xenon and/or krypton-lean liquid oxygen to a phase separator forming a low-pressure return liquid, and
compressing the low-pressure return liquid in a pump to form a high-pressure return liquid.

7. The process according to claim 6 , wherein the pressure of the high-pressure return liquid is greater than or equal to the pressure of the high-pressure liquid oxygen stream.

8. The process according to claim 1 , wherein a xenon recovery of 90% or greater is achieved, based on the concentration of xenon in the liquid oxygen feed.

9. The process according to claim 1 , wherein a xenon recovery of 95% or greater is achieved, based on the concentration of xenon in the liquid oxygen feed.

10. The process according to claim 1 , wherein the first portion of the liquid oxygen feed is between 10 and 50% of the liquid oxygen feed.

11. The process according to claim 1 , wherein a krypton recovery of 15% to 90% is achieved, based on the concentration of krypton in the liquid oxygen feed.

12. A process for the recovery of xenon and/or krypton from a liquid oxygen stream comprising oxygen and xenon and/or krypton, said process comprising:
providing a rare gas recovery system comprising a rare gas recovery column having a top, a bottom, at least one distillation zone, and a reboiling zone comprising a reboiler;
providing a liquid oxygen feed comprising oxygen and xenon and/or krypton;
providing a first portion of the liquid oxygen feed to the top of rare gas recovery column to form a reflux liquid;
providing a high-pressure liquid oxygen stream;
vaporizing a reboiler liquid in the reboiling zone to produce a mixture of a rising vapor and a xenon and/or krypton-enriched liquid stream;
contacting the rising vapor with the reflux liquid in the at least one distillation zone to effect stripping xenon and/or krypton from the rising vapor to the reflux liquid to produce the reboiler liquid;
removing the rising vapor from the top of the rare gas recovery column forming a xenon and/or krypton-lean gaseous oxygen stream;
removing the xenon and/or krypton-enriched liquid stream from the bottom of the rare gas recovery column;
passing the xenon and/or krypton-lean gaseous oxygen stream directly through a cold compressor forming a cold compressed oxygen stream;
passing the cold compressed oxygen stream through the reboiler producing condensed liquid oxygen by indirect heat exchange with the reboiler liquid in the reboiling zone;
removing the condensed liquid oxygen from the rare gas recovery system as xenon and/or krypton-lean liquid oxygen;
reducing the pressure of the high-pressure liquid oxygen stream in a valve, to a pressure greater than the operating pressure of the rare gas recovery column, forming a compressed liquid oxygen stream;
warming the compressed liquid oxygen stream by indirect heat exchange in a desubcooler to form the liquid oxygen feed;
passing the condensed liquid oxygen to the desubcooler and cooling, by indirect heat exchange with the compressed liquid oxygen stream, to produce a subcooled xenon and/or krypton-lean liquid oxygen;
wherein the rare gas recovery column is operated at an operating pressure of between 5 to 25 bara.

13. The process according to claim 12 , further comprising providing a second portion of the liquid oxygen feed to the rare gas recovery column at a position between the at least one distillation zone and the reboiling zone.

14. The process according to claim 12 , wherein the rare gas recovery column is operated at an operating pressure of between 10 and 20 bara.

15. The process according to claim 12 , further comprising reducing the pressure of the subcooled xenon and/or krypton-lean liquid oxygen in a valve, and passing the subcooled xenon and/or krypton-lean liquid oxygen to a phase separator forming a low-pressure return liquid, and
compressing the low-pressure return liquid in a pump to form a high-pressure return liquid.

16. The process according to claim 15 , wherein the pressure

Assignees

• Air Prod & Chem

Inventors

• Luo Xukun
• Berger Alan D
• Herron Donn Michael

Classifications

• B01D5/0006

  Coils or serpentines · CPC title

• F25J3/04412

  in a classical double column flowsheet, i.e. with thermal coupling by a main reboiler-condenser in the bottom of low pressure respectively top of high pressure column · CPC title

• F25J2235/50

  the fluid being oxygen · CPC title

• B01D3/4216

  Head stream · CPC title

• F25J3/04896

  Details of columns, e.g. internals, inlet/outlet devices · CPC title