Apparatus and method for separating air by cryogenic distillation
AssigneeL'Air Liquide, Societe Anonyme pour I'Etude et I'Exploitation des Procedes Georges Claude
InventorsMarie Cognard, Benoit Davidian, Richard Dubettier-Grenier
Life of this patent
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Abstract
Device for separating air comprises a pipe for withdrawing liquid oxygen from the low-pressure column and for sending it to a first pump, a pipe for sending liquid oxygen that has been pressurized to a pressure of below 9 bar as from the first pump to a vaporizer, a pipe for sending gaseous oxygen from the vaporizer to a main exchanger Where it is heated up, a pipe for sending liquid oxygen for purging from the vaporizer to a second pump to pressurize it and a pipe for sending the pressurized oxygen from the second pump to an exchanger where it vaporizes to form gaseous oxygen.
Claims19
1-15. (canceled)
An apparatus for separating air, the apparatus comprising:
- a double column comprising a medium-pressure column and a low-pressure column;
- a main exchanger;
- a vaporizer;
- a main compressor;
- means for sending all of the air to be treated in the double column to the main compressor in order to produce air substantially at the pressure P1 of the medium-pressure column;
- means for sending a portion of the air substantially at a high pressure P2 to the main exchanger and then to the vaporizer;
- a pipe for sending air at least partially condensed in the vaporizer to at least one of the columns;
- a pipe for sending air at the pressure P1 to the medium-pressure column;
- means of pressurizing;
- a pump;
- a pipe for withdrawing liquid oxygen from the low-pressure column and for sending it to the means of pressurizing;
- a pipe for sending the liquid oxygen that has been pressurized at a pressure below 9 bar abs from the means of pressurizing to the vaporizer;
- a pipe for sending gaseous oxygen from the vaporizer to the main exchanger to be heated for forming a first flow of gaseous oxygen;
- a purge pipe for sending the liquid purge oxygen from the vaporizer to the pump in order to pressurize the liquid purge oxygen;
- and
- a pipe for sending the pressurized oxygen from the pump to an exchanger to be vaporized,
- wherein the purge pipe is not connected to a purge liquid storage, and
- wherein the exchanger is connected to a pipe for compressed air connected to the main compressor and to a pipe connected to the double column, thereby forming a second flow of gaseous oxygen.
A method for separating air in an apparatus comprising a double column having a medium-pressure column and a low-pressure column;
- a main exchanger;
- a vaporizer;
- a main compressor;
- means of pressurizing;
- a pump;
- the method comprising the steps of:
- sending all of the air to he treated in the double column to the main compressor to produce air substantially at the pressure P1 of the medium-pressure column;
- sending a portion of the air substantially at a high pressure P2 to the main exchanger and then to the vaporizer;
- sending air at least partially condensed in the vaporizer to at least one of the columns;
- sending air at the pressure P1 to the medium-pressure column;
- withdrawing and pressurizing liquid oxygen from the low-pressure column to a pressure below 5 bar abs;
- sending the liquid oxygen that has been pressurized at a pressure below 5 bar abs to the vaporizer;
- sending a first flow of gaseous oxygen from the vaporizer to the main exchanger to be heated;
- and
- pressurizing the liquid purge oxygen of the vaporizer in the pump, wherein the liquid purge oxygen is pressurized without having been stored and is then vaporized in an exchanger via heat exchange with the air, compressed in the main compressor and intended for the double column, thereby forming a second flow of gaseous oxygen.
Dependencies are inferred from the claim text.