Process and installation for the production of oxygen and/or nitrogen under pressure

• US 5,515,687 A
• Filed: 10/26/1994
• Issued: 05/14/1996
• Est. Priority Date: 10/26/1993
• Status: Expired due to Fees

• Current Assignee: L'Air Liquide Societe Anonyme Pour L'Etude et L'Exploitation Des Procedes Georges Claude (L'Air Liquide SA)
• Original Assignee: L'Air Liquide Societe Anonyme Pour L'Etude et L'Exploitation Des Procedes Georges Claude (L'Air Liquide SA)
• Inventors: Arriulou, Pascal
• Primary Examiner(s): KILNER, CHRISTOPHER B
• Application Number:
  US08/329,321
• Time in Patent Office: 566 Days
• Field of Search: 62/38, 62/41
• US Class Current: 62/646
• CPC Class Codes: F25J 2290/12 Particular process parameters like pressure, temperature, ratios
• CPC Class Codes: F25J 3/04024 of purified feed air, so-called boosted air
• CPC Class Codes: F25J 3/0409 of oxygen
• CPC Class Codes: F25J 3/04169 by adsorption of the impurities adsorption in general B01D53/02
• CPC Class Codes: F25J 3/04296 Claude expansion, i.e. expanded into the main or high pressure column
• CPC Class Codes: F25J 3/04309 of nitrogen
• CPC Class Codes: F25J 3/04381 using work extraction by mechanical coupling of compression and expansion so-called companders
• CPC Class Codes: F25J 3/04393 using multiple or multistage gas work expansion
• CPC Class Codes: F25J 3/04412 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

Abstract

In this process for the distillation of air, of the type with a liquid oxygen pump (14) and with the vaporization of liquid oxygen under pressure, there are used, in addition to a principal compressor (1), at least three further compressors (9 to 11 ), of which two (9, 10) are mounted in series and supply the heat exchange line with air at a high pressure of the vaporization of oxygen. Air is withdrawn between these two further compressors, expanded to the medium pressure and introduced at the base of the medium pressure column (5), and at least one (11) of the three further compressors consumes the mechanical energy developed by the turbine (12).

Claims

1. In a process for the production of at least one of gaseous oxygen and nitrogen under pressure by distillation of air in an installation comprising a principal air compressor, an apparatus for the purification of air by adsorption, a heat exchange line and a double air distillation column comprising a medium pressure column and a low pressure column, wherein at least one of liquid oxygen and nitrogen is withdrawn from the double column, compressed by pumping, and vaporized under pressure by heat exchange with the air compressed by the principal compressor then further compressed;

the improvement wherein said further compression is effected by means of first and second compressors in series;

air is withdrawn between said first and second compressors, expanded in a Claude turbine to the medium pressure and introduced into the base of the medium pressure column;

a flow of air under a pressure equal to the output pressure of the principal compressor is further compressed by a third compressor, and the inlet temperature of the second compressor is in the region of atmospheric temperatures.

2. A process according to claim 1, wherein the third compressor is mounted between the principal compressor and the medium pressure column.

3. A process according to claim 1, wherein the third compressor is mounted between the principal compressor and the first compressor.

4. A process according to claim 1, wherein the third compressor is mounted between the first compressor and the Claude turbine.

5. A process according to claim 1, wherein nitrogen withdrawn from the head of the medium pressure column is expanded in a second turbine.

6. A process according to claim 5, wherein at least one of the first through the third compressors consumes the mechanical energy developed by at least one of the Claude turbine and the second turbine.

7. A process according to claim 6, wherein the mechanical energy developed by at least one of the Claude turbine and the second turbine is consumed by said third compressor.

8. In a process for the production of at least one of gaseous oxygen and nitrogen under pressure by distillation of air in an installation comprising a principal air compressor, an apparatus for the purification of air by adsorption, a heat exchange line and a double air distillation column comprising a medium pressure column and a low pressure column, wherein at least one of liquid oxygen and nitrogen is withdrawn from the double column, compressed by pumping, and vaporized under pressure by heat exchange with the air compressed by the principal compressor then further compressed;

the improvement wherein said further compression is effected by means of first and second compressors, in series; and

air is withdrawn between said first and second compressors, compressed in a third compressor, expanded in a Claude turbine to the medium pressure and introduced into the base of the medium pressure column.

9. A process according to claim 8, wherein the third compressor is mounted between the principal compressor and the medium pressure column.

10. A process according to claim 9, wherein the third compressor is mounted between the first compressor and the turbine.

11. A process according to claim 8, wherein nitrogen withdrawn from the head of the medium pressure column is expanded in a second turbine.

12. A process according to claim 11, wherein at least one of the first through the third compressors consumes the mechanical energy developed by at least one of the Claude turbine and the second turbine.

13. A process according to claim 12, wherein the mechanical energy developed by at least one of the Claude turbine and the second turbine is consumed by said third compressor.

14. In an installation for the production of at least one of gaseous oxygen and nitrogen under pressure by distillation of air comprising a principal air compressor, an apparatus for the purification of air by adsorption, a heat exchange line, a double air distillation column comprising a medium pressure column and a low pressure column, a pump connected upstream of the double column and downstream of vaporization passages of the heat exchange line, and means for further compressing air supplied by the principal compressor and emptying into the air cooling passages of the heat exchange line;

the improvement wherein the further compression means comprise at least first and second compressors in series;

a conduit tapped between said first and second compressors supplied a Claude turbine for the expansion of air to the medium pressure column; and

the installation comprises a third compressor supplied by air under a pressure equal to the output pressure of the principal compressor, said third compressor being directly connected to the outlet of the principal compressor and said second compressor being connected upstream of said heat exchange line.

15. An installation according to claim 14, wherein the third compressor is mounted between the principal compressor and the medium pressure column.

16. An installation according to claim 14, wherein the third compressor is mounted between the principal compressor and the first compressor.

17. An installation according to claim 14, wherein the third compressor is mounted between the first compressor and the Claude turbine.

18. An installation according to claim 14, which further comprises a second turbine for the expansion of nitrogen connected upstream of the head of the medium pressure column.

19. An installation according to claim 18, wherein at least one of the first through the third compressors is driven by the mechanical energy developed by at least one of the Claude turbine and the second turbine.

20. An installation according to claim 19, wherein said third compressor is driven by the mechanical energy developed by at least one of the Claude turbine and the second turbine.

21. In an installation for the production of at least one of gaseous oxygen and nitrogen under pressure by distillation of air a principal air compressor, an apparatus for the purification of air by adsorption, a heat exchange line, a double air distillation column comprising a medium pressure column and a low pressure column, a pump connected upstream of the double column and downstream of vaporization passages of the heat exchange line, and means for further compressing air supplied by the principal compressor and emptying into the air cooling passages of the heat exchange line;

the improvement wherein the further compression means comprise at least first and second compressors in series;

a conduit tapped between said first and second compressors supplies a third compressor whose outlet is connected to the inlet of a Claude turbine for the expansion of air to the medium pressure whose output is connected to the base of the medium pressure column.

22. An installation according to claim 21, wherein the third compressor is mounted between the principal compressor and the medium pressure column.

23. An installation according to claim 22, wherein the third compressor is mounted between the first compressor and the Claude turbine.

24. An installation according to claim 21, which further comprises a second turbine for the expansion of nitrogen connected upstream of the head of the medium pressure column.

25. An installation according to claim 24, wherein at least one of the first through the third compressors is driven by the mechanical energy developed by at least one of the Claude turbine and the second turbine.

26. An installation according to claim 25, wherein said third compressor is driven by the mechanical energy developed by at least one of the Claude turbine and the second turbine.