Single packaged air separation apparatus with reverse main heat exchanger

Patent metadata

Field	Value
Publication number	US-2021063085-A1
Application number	US-201716958037-A
Country	US
Kind code	A1
Filing date	Dec 25, 2017
Priority date	Dec 25, 2017
Publication date	Mar 4, 2021
Grant date	—

Abstract

A cryogenic air separation setup in a cold box, wherein gaseous oxygen under elevated pressure is produced through hydraulic force caused by the geodetic distance between where liquid oxygen is drawn from the distillation column and where liquid oxygen is vaporized to form gaseous oxygen, such as in an auxiliary evaporator. To increase the vertical distance between the above-mentioned two location, the components are arranged directly below one another in the following sequence: the lower-pressure column, the main condenser evaporator, the higher-pressure column, the subcooler, the main heat exchanger and the auxiliary evaporator). In particular, the main heat-exchanger is positioned with the cold-end on the top to optimize piping expenditure

First claim

1 - 11 . (canceled)

12 . An air separation apparatus comprising:
(a) a main air compressor and an air cooling unit in flow communication with an air purification unit to produce a compressed and purified feed air stream; (b) a first column, a main condenser evaporator and a second column, which are arranged in above sequence below one another, wherein the first column is operated at a higher pressure than the second column; (c) an auxiliary evaporator having a liquefaction space and a vaporization space, which is disposed below the bottom of the first column; (d) a main heat exchanger disposed in between the first column and the auxiliary evaporator for indirect heat exchange between the compressed and purified feed air stream and return gaseous streams from the second column; (e) means for introducing the compressed and purified feed air stream into at least the first column; (f) means for introducing at least a fraction from the first column into the second column; (g) means for transporting a liquid oxygen stream from the main condenser evaporator into the vaporization space of the auxiliary evaporator, wherein at least part of the vaporized gaseous oxygen stream is warmed up in the main heat exchanger to form gaseous oxygen product and the remaining liquid oxygen stream is withdrawn as liquid oxygen product; and (h) means for providing refrigeration to the air separation apparatus; wherein the main heat exchanger is set up in a way that the return gaseous streams enter from the cold end at the top, and exit from the warm end at the bottom of the main heat exchanger.

13 . The air separation apparatus of claim 12 , further comprising a subcooler disposed in between the first column and the main heat exchanger, wherein the return gaseous streams undergo heat exchange with liquid streams passed from the column, then said return gaseous streams enter into the cold end at the top of the main heat exchanger.

14 . The air separation apparatus of claim 13 , further comprising means for introducing at least partially liquefied a first part of feed air stream into the liquefaction space of the auxiliary evaporator and after partial or total condensation therein, further into a phase separator for separation into a gaseous feed air stream and a liquid feed air stream.

15 . The air separation apparatus of claim 14 , further comprising a turbine expander for expanding a second part of feed air stream before it enters into the first column or the second column to provide refrigeration to the air separation apparatus.

16 . The air separation apparatus of claim 12 , wherein the second column, the main condenser evaporator, the first column, optionally the subcooler, the main heat exchanger and the auxiliary evaporator are on top of one another in the above sequence and are housed in one cold box.

17 . A process for producing gaseous oxygen product under elevated pressure in the air separation apparatus according to claim 1 , comprising:
(a) cooling a compressed and purified feed air stream in the main heat exchanger through indirect heat exchange with return gaseous streams from the second column followed by introducing at least part of gaseous feed air stream into the first column; (b) separating the gaseous feed air stream into oxygen-rich liquid at the bottom of the first column and transporting said stream into the second column to form bottom liquid and waste nitrogen; (c) condensing medium pressure gaseous nitrogen from the top of the first column against bottom liquid from the second column in the main condenser evaporator to form reflux for the first column and liquid oxygen; (d) withdrawing liquid oxygen from the main condenser evaporator into the vaporization space of the auxiliary evaporator, wherein at least part of the vaporized gaseous oxygen stream is warmed up in the main heat exchanger to form gaseous oxygen product and the remaining liquid oxygen stream is withdrawn as liquid oxygen product; and (e) providing refrigeration to the air separation apparatus through expanding at least part of the compressed and purified feed air stream in a turbine expander before introducing it into the second column or optionally through external source; wherein the main heat exchanger is set up in a way that the return gaseous streams enter from the cold end at the top, and exit from the warm end at the bottom of the main heat exchanger.

18 . The process of claim 17 , wherein the compressed and purified feed air stream is divided into at least a first part of feed air stream and a second part of feed air stream in the main heat exchanger, the first part of feed air stream being delivered into the liquefaction space of the auxiliary evaporator to be partially or totally condensed and further delivered into a phase separator for separation into the gaseous feed air stream and a liquid feed air stream, and the gaseous feed air stream being fed into the first column and the liquid feed air stream being fed into the second column.

19 . The process of claim 18 , wherein the second part of feed air stream is expanded in a turbine expander before being routed into the second column.

20 . The process of claim 17 , wherein a liquid nitrogen and a lean liquid are removed from the first column and transported into the second column.

21 . The process of claim 20 , wherein low pressure gaseous nitrogen is withdrawn from the second column.

22 . The process of claim 21 , wherein the liquid feed air stream, the oxygen-rich liquid, the lean liquid and the liquid nitrogen are subcooled in a subcooler against return gaseous streams including waste nitrogen and optionally low pressure gaseous nitrogen before being introduced into the second column.

Assignees

• Lair Liquide Sa Pour Letude Et Iexploitation Des Procedes Georges Claude
• Lair Liquide Sa Pour Letude Et L?Exploitation Des Procedes Georges Claude

Inventors

• Briglia Alain
• Kurtz Remy
• Day Eric
• Xie Huali
• Fara Baptiste

Classifications

• F25J3/04206

  including a so-called "auxiliary vaporiser" for vaporising and producing a gaseous product · CPC title

• F25J3/04303

  Lachmann expansion, i.e. expanded into oxygen producing or low pressure column · CPC title

• F25J3/04872

  Vertical layout of cold equipments within in the cold box, e.g. columns, heat exchangers etc. · CPC title

• F25J3/0409 Primary

  of oxygen · CPC title

• F25J2205/04

  in the feed line, i.e. upstream of the fractionation step · CPC title