Refrigeration cycle for liquid oxygen densification

Patent metadata

Field	Value
Publication number	US-11293671-B2
Application number	US-202016922067-A
Country	US
Kind code	B2
Filing date	Jul 7, 2020
Priority date	Jan 16, 2017
Publication date	Apr 5, 2022
Grant date	Apr 5, 2022

Abstract

Closed-loop refrigeration cycles for liquid oxygen densification are disclosed. The disclosed refrigeration cycles may be turbine-based refrigeration cycles or a Joule-Thompson (JT) expansion valve based refrigeration cycles and include a refrigerant or working fluid comprising a mixture of neon or helium together with nitrogen and/or oxygen.

First claim

What is claimed is:

1. A closed-loop refrigeration system for liquid oxygen densification comprising:
a compressor configured to compress a working fluid having between 85 mol % and 95 mol % neon and/or helium and between 5 mol % and 15 mol % nitrogen and/or oxygen from a pressure above ambient pressure to a pressure between 120 psia and 155 psia;
a heat exchanger in fluid communication with the outlet of the compressor configured to receive the compressed working fluid and cool the compressed working fluid via indirect heat exchange with a gaseous nitrogen stream and a liquid nitrogen stream to produce a cold, compressed working fluid;
a turbine in fluid communication with the heat exchanger and configured to expand the cold, compressed working fluid and produce a refrigeration stream of expanded working fluid, wherein the turbine has an expansion ratio of less than 10.0 and the expanded working fluid exiting the turbine is preferably between 5 mol % to 10 mol % liquid;
an oxygen cooler in fluid communication with the turbine, the oxygen cooler configured to receive a stream of liquid oxygen and the refrigeration stream from the turbine, and subcool the stream of liquid oxygen to a temperature less than 66.5 K via indirect heat exchange with the refrigeration stream of expanded working fluid to produce a densified liquid oxygen stream; and
a recirculating conduit configured to recirculate the warmed refrigeration stream to an inlet of the compressor where the warmed refrigeration stream is compressed as the working fluid.

2. The closed-loop refrigeration system of claim 1 , wherein the working fluid at the inlet of the compressor is at a temperature of between 65 K and 80 K.

3. The closed-loop refrigeration system of claim 1 , wherein the heat exchanger is further configured to further warm the warmed refrigeration stream via indirect heat exchange with the stream of cold, compressed working fluid and wherein the working fluid at the inlet of the compressor is at a temperature of between 100 K and 310 K.

4. The closed-loop refrigeration system of claim 1 , wherein the working fluid is selected from the group essentially consisting of: (i) a mixture of neon with nitrogen; (ii) a mixture of neon with oxygen; (iii) a mixture of neon with nitrogen and oxygen; (iv) a mixture of helium with nitrogen; (v) a mixture of helium with oxygen; (vi) a mixture of helium with nitrogen and oxygen; or (vii) a mixture of neon and helium with nitrogen and oxygen.

5. A method of densifying a liquid oxygen stream in a closed-loop refrigeration cycle, the method comprising the steps of:
compressing a working fluid having between 85 mol % and about 95 mol % neon and/or helium and between 5 mol % and 15 mol % nitrogen and/or oxygen in a compressor from a pressure above ambient pressure to a pressure between 120 psia and 155 psia;
cooling the compressed working fluid via indirect heat exchange with a gaseous nitrogen stream or a liquid nitrogen stream or both to produce a cold, compressed working fluid;
expanding the cold, compressed working fluid in a turbine to produce a refrigeration stream of expanded working fluid at a temperature of less than 66.5 K, wherein the turbine has an expansion ratio of less than 10.0 and the expanded working fluid exiting the turbine is preferably between 5 mol % to 10 mol % liquid;
subcooling a stream of liquid oxygen via indirect heat exchange with the refrigeration stream of expanded working fluid to produce a densified liquid oxygen stream; and
recirculating the warmed refrigeration stream to the compressor;
wherein the warmed refrigeration stream is compressed as the working fluid to form a closed-loop refrigeration cycle.

Assignees

• Prosser Neil M
• Dray James R
• Belanger Paul W
• Shelat Maulik R
• Praxair Technology Inc

Inventors

• Prosser Neil M
• Dray James R
• Belanger Paul W
• Shelat Maulik R

Classifications

• F25B25/005

  using primary and secondary systems · CPC title

• F25J1/0017

  Oxygen · CPC title

• F02K9/425

  Propellants · CPC title

• F25B9/02 Primary

  using Joule-Thompson effect; using vortex effect · CPC title

• F25J1/0292

  Refrigerant compression by cold or cryogenic suction of the refrigerant gas · CPC title