Cryogenic industrial gas liquefaction system

• US 6,220,053 B1
• Filed: 01/10/2000
• Issued: 04/24/2001
• Est. Priority Date: 01/10/2000
• Status: Expired due to Term

• Current Assignee: Praxair Technology Incorporated (Linde Plc)
• Original Assignee: Praxair Technology Incorporated (Linde Plc)
• Inventors: Hass, Joseph William Jr., Marino, Michael Anthony, Arman, Bayram, Schaub, Herbert Raymond
• Primary Examiner(s): Doerrler, William
• Assistant Examiner(s): Drake, Malik N.
• Application Number:
  US09/479,986
• Time in Patent Office: 470 Days
• Field of Search: 626/13, 626/19
• US Class Current: 62/613
• CPC Class Codes: F25J 1/0015 Nitrogen
• CPC Class Codes: F25J 1/0017 Oxygen
• CPC Class Codes: F25J 1/0022 Hydrocarbons, e.g. natural gas
• CPC Class Codes: F25J 1/0037 of a return stream
• CPC Class Codes: F25J 1/0045 by vaporising a liquid return stream
• CPC Class Codes: F25J 1/0202 in a quasi-closed internal refrigeration loop F25J1/0208, F25J1/0219, F25J1/0224 take precedence
• CPC Class Codes: F25J 1/0234 Integration with a cryogenic air separation unit cryogenic separation of air F25J3/04
• CPC Class Codes: F25J 1/0262 Details of the cold heat exchange system constructional details F25J5/00, construction of cold-exchangers in general F28
• CPC Class Codes: F25J 1/0288 using work extraction by mechanical coupling of compression and expansion of the refrigerant, so-called companders
• CPC Class Codes: F25J 2270/06 with multiple gas expansion loops
• CPC Class Codes: F25J 2290/34 Details about subcooling of liquids
• CPC Class Codes: F25J 2290/40 Vertical layout or arrangement of cold equipments within in the cold box, e.g. columns, condensers, heat exchangers etc.

Abstract

A system for liquefying industrial gas wherein industrial gas is compressed to two levels using a first and a second compression system and then is processed in a heat exchanger having horizontally oriented sensible heat exchange passages and vertically oriented condensing heat exchange passages.

Claims

1. A method for liquefying an industrial gas comprising:

(A) compressing industrial gas to produce compressed industrial gas and further compressing a portion of the compressed industrial gas to produce a compressed first industrial gas portion and a further compressed second industrial gas portion;

(B) cooling the first industrial gas portion, turboexpanding the cooled first industrial gas portion, and warming the turboexpanded first industrial gas portion by horizontal countercurrent flow indirect heat exchange with the further compressed second industrial gas portion to cool the further compressed second industrial gas portion;

(C) dividing the cooled second industrial gas portion into a first part and a second part, turboexpanding said first part and warming the turboexpanded first part by indirect heat exchange with the second part of the cooled second industrial gas portion in vertical flow to liquefy said second part; and

(D) recovering the liquefied second industrial gas part as product liquefied industrial gas.

2. The method of claim 1 wherein the liquefied second part is subcooled prior to recovery as product liquefied industrial gas.

3. The method of claim 2 wherein a partial flow of the subcooled liquefied second part is reduced in pressure and then warmed by indirect heat exchange to carry out the subcooling of the liquefied second part.

4. The method of claim 3 wherein the resulting warmed partial flow is further warmed by vertical countercurrent indirect heat exchange with the cooled second industrial gas part to assist in liquefying said second part.

5. The method of claim 4 wherein the resulting further warmed partial flow is still further warmed by horizontal countercurrent indirect heat exchange with the further compressed second industrial gas portion to assist in cooling said second industrial gas portion.

6. Apparatus for liquefying an industrial gas comprising:

(A) a heat exchanger having horizontally oriented heat exchange passages and having vertically oriented heat exchange passages in flow communication with the horizontally oriented heat exchange passages;

(B) a first compression system, a second compression system, means for providing industrial gas to the first compression system and from the first compression system to a horizontally oriented passage of the heat exchanger, and means for providing industrial gas from the first compression system to the second compression system and from the second compression system to a horizontally oriented passage of the heat exchanger;

(C) a first turboexpander, a second turboexpander, means for passing industrial gas from a horizontally oriented passage of the heat exchanger to the first turboexpander and from the first turboexpander to another horizontally oriented passage of the heat exchanger and means for passing industrial gas from the heat exchanger to the second turboexpander and from the second turboexpander to either a vertically oriented passage or to a horizontally oriented passage of the heat exchanger; and

(D) means for recovering liquefied industrial gas from a vertically oriented passage of the heat exchanger.

7. The apparatus of claim 6 further comprising a subcooler wherein the means for recovering liquefied industrial gas from a vertically oriented passage of the heat exchanger includes the subcooler.

8. The apparatus of claim 7 further comprising a throttle valve, means for passing fluid from the subcooler to the throttle valve, and means for passing fluid from the throttle valve back to the subcooler.

9. The apparatus of claim 8 further comprising means for passing fluid from the subcooler to the heat exchanger.

10. The apparatus of claim 6 further comprising means for passing fluid from the heat exchanger to the first compression system.