Method for producing pressurized gaseous oxygen through the cryogenic separation of air

Patent metadata

Field	Value
Publication number	US-9964354-B2
Application number	US-201615000583-A
Country	US
Kind code	B2
Filing date	Jan 19, 2016
Priority date	Jan 19, 2016
Publication date	May 8, 2018
Grant date	May 8, 2018

Abstract

A method is provided for production of gaseous oxygen at high pressures by splitting a main air feed into at least three separate streams, with the first stream being fed to a heat exchanger and then a column system for rectification; the second stream being further compressed in a warm booster, partially cooled in the heat exchanger, expanded in a turbine coupled to the warm booster and then fed to the column system; the third stream being expanded in a warm expander before being introduced to the heat exchanger and introduced to the column system. In certain embodiments, substantially all of the main air feed is eventually introduced to the column system for rectification, resulting in reduced sizing of a main air compressor and improved product recoveries.

First claim

I claim:

1. A method for producing pressurized gaseous oxygen through the cryogenic separation of air, the method comprising the steps of:
obtaining a main air feed comprising filtered and compressed air;
splitting the main air feed into at least a first air fraction, a second air fraction, and a third air fraction;
fully cooling the first air fraction in a heat exchanger to a temperature suitable for rectification of the first air fraction to form a cooled air feed;
withdrawing the cooled air feed from the heat exchanger and introducing the cooled air feed to a column system under conditions effective for rectification of the cooled air feed into low pressure gaseous nitrogen (LP GAN), liquid oxygen (LOX), liquid nitrogen (LIN), and high pressure gaseous nitrogen (HP GAN), wherein the column system comprises a double column having a higher pressure column and a lower pressure column;
warming the LP GAN, LOX, and HP GAN in the heat exchanger;
boosting the second air fraction in a first warm booster to form a boosted second air fraction;
partially cooling a first portion of the boosted second air fraction in the heat exchanger and then expanding the first portion of the boosted second air fraction in a cold turbine to form an expanded second air fraction;
introducing the expanded second air fraction to the column system;
compressing a second portion of the boosted second air fraction in a second warm booster to form a second boosted second air fraction;
fully cooling the second boosted second air fraction in the heat exchanger to form a second cooled air feed;
withdrawing the second cooled air feed from the heat exchanger and introducing the second cooled air feed to the column system;
expanding the third air fraction using a warm expander to create an expanded third air fraction, wherein the warm expander powers the second warm booster; and
cooling the expanded third air fraction in the heat exchanger before introducing the expanded third air fraction to the column system for rectification.

2. The method as claimed in claim 1 , wherein the expanded second air fraction is at the same pressure as the higher pressure column.

3. The method as claimed in claim 1 , wherein the main air feed has a pressure of least 10 bar.

4. The method as claimed in claim 1 , wherein the main air feed has a pressure of at least 20 bar.

5. The method as claimed in claim 1 , wherein the cold turbine is coupled to the first warm booster.

6. The method as claimed in claim 1 , further comprising withdrawing LIN from the column system as product.

7. The method as claimed in claim 1 , wherein the LOX is vaporized in the heat exchanger and has a pressure of about 20-60 bar after being warmed in the heat exchanger.

8. The method as claimed in claim 1 , wherein substantially all of the main air feed is introduced to the column system for rectification.

9. The method as claimed in claim 1 , wherein substantially none of the main air feed is vented to the atmosphere.

10. The method as claimed in claim 1 , wherein the third air fraction is at substantially the same pressure as the second air fraction and the first air fraction.

11. The method as claimed in claim 1 , wherein the expanded second air fraction and the expanded third air fraction are sent to the same location within the column system.

12. The method as claimed in claim 1 , wherein the column system comprises an absence of a mixing column.

13. The method as claimed in claim 1 , wherein the column system consists essentially of a higher pressure column, a lower pressure column and an argon column.

14. A method for producing pressurized gaseous oxygen through the cryogenic separation of air, the method comprising a first operation mode and a second operation mode, wherein in both the first operation mode and the second operation mode, wherein in the first operation mode, the method comprises the steps of:
obtaining a main air feed comprising filtered and compressed air having a pressure of at least 15 bara;
splitting the main air feed into at least a first air fraction, a second air fraction, and a third air fraction;
fully cooling the first air fraction in a heat exchanger to a temperature suitable for rectification of the first air fraction to form a cooled air feed;
withdrawing the cooled air feed from the heat exchanger and introducing the cooled air feed to a column system under conditions effective for rectification of the cooled air feed into low pressure gaseous nitrogen (LP GAN), liquid oxygen (LOX), liquid nitrogen (LIN), and high pressure gaseous nitrogen (HP GAN), wherein the column system comprises a double column having a higher pressure column and a lower pressure column;
warming the LP GAN, LOX, and HP GAN in the heat exchanger;
boosting the second air fraction in a first warm booster to form a boosted second air fraction;
partially cooling a first portion of the boosted second air fraction in the heat exchanger and then expanding the first portion of the boosted second air fraction in a cold turbine to form an expanded second air fraction;
introducing the expanded second air fraction to the column system;
expanding the third air fraction using a warm expander to create an expanded third air fraction; and
cooling the expanded third air fraction in the heat exchanger before introducing the expanded third air fraction to the column system for rectification, wherein in the second operation mode, the method further comprises the steps of:
opening a Joule-Thompson valve in fluid communication with the boosted second air fraction and diverting a third portion of the boosted second air fraction through the Joule-Thompson valve and combining the third portion of the boosted second air fraction with the first air fraction upstream the heat exchanger;
introducing the third portion of the boosted second air fraction, along with the first air fraction, into the heat exchanger for cooling before introducing the third portion of the boosted second air fraction, along with the first air fraction, to the column system;
compressing a second portion of the boosted second air fraction in a second warm booster to form a second boosted second air fraction;
fully cooling the second boosted second air fraction in the heat exchanger;
expanding the cooled second boosted second air fraction across a valve and then introducing the expanded cooled second boosted second air fraction to the higher pressure column,
wherein the method switches from the first operation mode to the second operation mode based upon a determination to produce less quantity of liquid products, wherein the liquid products comprise LOX and LIN.

15. A method for producing pressurized gaseous oxygen through the cryogenic separation of air, the method comprising the steps of:
obtaining a main air feed comprising filtered and compressed air having a pressure of at least 15 bara;
splitting the main air feed into at least a first air fraction, a second air fraction, and a third air fraction;
fully cooling the first air fraction in a heat exchanger to a temperature suitable for rectification of the first air fraction to form a cooled air feed;
withdrawing the cooled air feed from the heat exchanger and introducing the cooled air feed to a column system under conditions effective for rectification of the cooled air feed into low pressure gaseous nitrogen (LP GAN), liquid oxygen (LOX), liquid nitrogen (LIN), and high pressure gaseous nitrogen (HP GAN), wherein the column system comprises a double column having a higher pressure column and a lower pressure column;
warming the LP GAN, LOX, and HP GAN in the

Assignees

• Air Liquide
• Air Liquide

Inventors

• Musicus Paul

Classifications

• F25J2240/42

  the fluid being air · CPC title

• F25J3/04296

  Claude expansion, i.e. expanded into the main or high pressure column · CPC title

• F25J3/04393

  using multiple or multistage gas work expansion · CPC title

• F25J2245/40

  the recycled stream being air · CPC title

• F25J3/04812 Primary

  Different modes, i.e. "runs" of operation (F25J3/04472 takes precedence) · CPC title