Refrigeration – Cryogenic treatment of gas or gas mixture – Liquefaction
Reexamination Certificate
2000-01-10
2001-04-24
Doerrler, William (Department: 3744)
Refrigeration
Cryogenic treatment of gas or gas mixture
Liquefaction
C062S619000
Reexamination Certificate
active
06220053
ABSTRACT:
TECHNICAL FIELD
This invention relates generally to cryogenic heat exchange for the liquefaction of industrial gases.
BACKGROUND ART
Liquefaction of low boiling point gases, such as oxygen and nitrogen, is both capital and energy intensive. Typically practitioners have addressed the issue of improving liquefier performance by using multiple turbines and by using liquid expanders. Generally heat exchangers used with these systems are oriented in the vertical plane due to process hydraulic effects. This conventional practice leads to long piping runs of large bore warm end piping and also requires the utilization of significant footprint space for aftercooler heat exchangers and associated piping.
Accordingly it is an object of this invention to provide an industrial gas liquefaction system having an improved design and lower costs than conventional industrial gas liquefaction systems.
SUMMARY OF THE INVENTION
The above and other objects which will become apparent to those skilled in the art upon a reading of this disclosure, are attained by the present invention, one aspect of which is:
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.
Another aspect of the invention is:
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 either to 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.
As used herein, the term “indirect heat exchange” means the bringing of two fluids into heat exchange relation without any physical contact or intermixing of the fluids with each other.
As used herein, the term “compressor” means a device which accepts gaseous fluid at one pressure and discharges it at a higher pressure.
As used herein, the terms “turboexpansion” and “turboexpander” mean respectively method and apparatus for the flow of high pressure gas through a turbine to reduce the pressure and the temperature of the gas, thereby generating refrigeration.
As used herein, the terms “subcooling” and “subcooler” mean respectively method and apparatus for cooling a liquid to be at a temperature lower than the saturation temperature of that liquid for the existing pressure.
As used herein the term “industrial gas” means a fluid comprised primarily of one or more of nitrogen, oxygen, natural gas or one or more other hydrocarbons.
REFERENCES:
patent: 3677019 (1972-07-01), Olszewski
patent: 4638639 (1987-01-01), Marshall et al.
patent: 4778497 (1988-10-01), Hanson et al.
patent: 4894076 (1990-01-01), Dobracki et al.
patent: 5231835 (1993-08-01), Beddome et al.
patent: 5799505 (1998-09-01), Bonaquist et al.
patent: 5802874 (1998-09-01), Voit
patent: 5836173 (1998-11-01), Lynch et al.
Arman Bayram
Hass, Jr. Joseph William
Marino Michael Anthony
Schaub Herbert Raymond
Doerrler William
Drake Malik N.
Ktorides Stanley
Praxair Technology Inc.
LandOfFree
Cryogenic industrial gas liquefaction system does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Cryogenic industrial gas liquefaction system, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Cryogenic industrial gas liquefaction system will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2512460