Method and device for separation at cryogenic temperature

Patent metadata

Field	Value
Publication number	US-2016223253-A1
Application number	US-201415021035-A
Country	US
Kind code	A1
Filing date	Sep 10, 2014
Priority date	Sep 10, 2013
Publication date	Aug 4, 2016
Grant date	—

Abstract

In a method for separating air by separation at sub-ambient temperature, a first heat pump, using the magnetocaloric effect, exchanges heat between a cold source at sub-ambient temperature and a hot source at sub-ambient temperature, thus providing at least some of the separation energy, and a second heat pump, using the magnetocaloric effect, exchanges heat between a cold source at sub-ambient temperature and a hot source at ambient temperature thus providing at least some of the cold needed to maintain the refrigeration balance of the method, the separation taking place in a single column at a pressure of below 2 bara.

First claim

1 - 14 . (canceled)

15 . A method for separating air at a cryogenic temperature, the method comprising the steps of:
a) exchanging heat directly or indirectly between a first cold source at a first cryogenic temperature and a first hot source at a second cryogenic temperature using at least one first heat pump that uses the magnetocaloric effect, thus providing at least some of the separation energy, wherein the at least one first heat pump is referred to as a separation heat pump; and b) exchanging heat directly or indirectly between a second cold source at a first cryogenic temperature and a second hot source at a temperature higher than the first temperature using at least a second heat pump that uses the magnetocaloric effect, thereby providing at least some of the cold needed to maintain the refrigeration balance of the method, the separation taking place in a single column or a set of columns, the pressure of the single column or of the columns of the set being below 2 bara, wherein the first cold source and the first hot source are directly or indirectly thermally connected to the single column or to one column of the set, wherein the second heat pump is referred to as a refrigeration balance heat pump, wherein the first and second heat pumps use the magnetocaloric effect and in that the second cold source is selected from the group consisting of air intended to be separated in the single column or the set of columns, of a fluid coming from the single column or from the set of columns, and combinations thereof.

16 . The method as claimed in claim 15 , in which the first heat pump transfers heat directly or indirectly from the top of the single column or of a column of the set.

17 . The method as claimed in claim 16 , wherein the heat transfer is done by condensing gas of the column or of a column of the set, towards the bottom of the column or of a column of the set, and by vaporizing liquid of the single column or of a column of the set.

18 . The method as claimed in claim 15 , wherein the pressure of the single column or of the columns of the set is below 1.5 bara.

19 . The method as claimed in claim 15 , wherein the single column or of the columns of the set is at a pressure that differs from atmospheric pressure only by the losses in pressure head of elements that connect the column or columns with the atmosphere.

20 . The method as claimed in claim 15 , in which the first and second heat pumps are thermally connected to one another via the single column.

21 . The method as claimed in claim 15 , in which the second heat pump directly or indirectly at least partially condenses the air before the air is introduced into the single column or into one of the columns of the set.

22 . The method as claimed in claim 15 , in which the second heat pump directly or indirectly completely condenses part of the air before the completely condensed part of the air is introduced into the single column or into one of the columns of the set.

23 . The method as claimed in claim 22 , wherein the completely condensed part of the air is introduced into the single column at a point above the supply of the rest of the air.

24 . The method as claimed in claim 15 , in which the second heat pump directly or indirectly cools or condenses a fluid coming from the single column or from one of the columns of the set in a heat exchanger thereby allowing an exchange of heat between the fluid and a heat-transfer fluid of the second heat pump.

25 . The method as claimed in claim 15 , in which at least a fluid that is to be separated and/or that comes from the separation of the column or of one of the columns of the set is brought into direct contact with a magnetocaloric material of one of the first and second heat pumps.

26 . The method as claimed in claim 15 , in which the exchange of heat is performed at least in part between a fluid that is to be separated and/or that comes from the separation of the column or of a column of the set and a heat-transfer fluid that has been in contact with a magnetocaloric material of one of the first and second heat pumps, through an exchanger.

27 . The method as claimed in claim 15 , in which the exchange of heat is performed at least in part between a fluid that is to be separated and/or that comes from the separation of the column or of a column of the set and a heat-transfer fluid that has been in contact with a magnetocaloric material of a first and second of the heat pumps, through an intermediate heat-transfer circuit.

28 . The method as claimed in claim 15 , in which the second heat pump comprises a heat exchanger allowing an exchange of heat between the air that is to be distilled and a heat-transfer fluid of the heat pump.

29 . The method as claimed in claim 28 , in which the heat exchanger exchanges heat only between the air and the heat-transfer fluid.

30 . The method as claimed in claim 28 , in which the heat exchanger is used to cool all of the air intended for distillation.

31 . The method as claimed in claim 15 , in which the first and second heat pumps have no heat exchanger in common.

32 . A device for separating air using a method of separation at cryogenic temperature comprising:
a single column or a set of columns in which cryogenic separation takes place; means for sending a mixture of air gases to the column or a column of the set; means for withdrawing at least one fluid enriched in a component of the mixture from the column; at least a first heat pump, using the magnetocaloric effect, configured to heat directly or indirectly between a cold source at cryogenic temperature and a hot source at cryogenic temperature, thereby supplying at least part of the separation energy, wherein the first heat pump is referred to as the separation heat pump; and at least a second heat pump, using the magnetocaloric effect, referred to as the refrigeration balance heat pump, wherein the second heat pump is configured to exchange heat directly or indirectly between a cold source at a first cryogenic temperature consisting of the air intended to be separated in the single column or the set of columns and a hot source at a temperature higher than the first temperature, thus supplying at least a portion of the cold needed to maintain a refrigeration balance when in operation, wherein the pressure of the single column or of the columns of the set is below 2 bara, so that the column is or the columns are connected to the atmosphere via at least one pipe that comprises an absence of an expansion means, wherein the first cold source and the first hot source are directly or indirectly thermally connected to the single column or to a column of the set.

Assignees

• Air Liquide

Inventors

• Cardon Guillaume
• Correia Anacleto Antony
• Davidian Benoit
• Lix Clement
• Saulnier Bernard

Classifications

• F25J3/044

  using a single pressure main column system only (F25J3/0446, F25J3/04624, F25J3/04636 take precedence) · CPC title

• F25J3/04412 Primary

  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 · CPC title

• F25J3/04278

  using external refrigeration units, e.g. closed mechanical or regenerative refrigeration units · CPC title

• F25B21/00

  Machines, plants or systems, using electric or magnetic effects · CPC title

• F25J2210/06

  Splitting of the feed stream, e.g. for treating or cooling in different ways · CPC title