Process and apparatus for the separation of air by cryogenic distillation
AssigneeL'Air Liquide, Societe Anonyme pour l'Etude et l'Exploitation des Procedes Georges Claude
InventorsBao Ha, Jean-Renaud Brugerolle
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Abstract
The present invention relates to a process and apparatus for the separation of air by cryogenic distillation. In particular, it relates to a process for separation of air using three cryogenic distillation columns for the production of gaseous oxygen. Certain embodiments of the invention are particularly efficient for the production of gaseous oxygen at pressures between 30 and 45 bars abs, in which the oxygen is produced by removing liquid oxygen from a distillation column, pressurizing the oxygen and vaporizing the pressurized liquid by heat exchange with air.
Claims16
1-15. (canceled)
A process for the separation of air by cryogenic distillation in which air is purified, cooled and sent to a first distillation column of a column system, wherein the air is separated into an oxygen enriched liquid and a nitrogen enriched gas, the process comprising the steps of:
- introducing oxygen enriched liquid or a liquid derived therefrom from the first column to a top condenser of a second column operating at a lower pressure than the first column, wherein the oxygen enriched liquid or a liquid derived therefrom is partially vaporized;
- warming the bottom of the second column via a bottom reboiler;
- introducing liquid from the bottom of the second column to an intermediate point of a third column operating at a lower pressure than the second column;
- introducing nitrogen enriched liquid from the top of the second column to the top of the third column;
- and
- removing oxygen rich liquid from the bottom of the third column, such that the oxygen rich liquid is pressurized and vaporized by heat exchange with air,
- wherein the oxygen enriched liquid from the top condenser of the second column is sent to an intermediate point of the second column to be separated therein.
An apparatus for the separation of air by cryogenic distillation, the apparatus comprising:
- a column system having a first column, a second column and a third column;
- a heat exchanger;
- means configured to send purified, cooled air from the heat exchanger to the first distillation column wherein the purified, cooled air is separated into an oxygen enriched liquid and a nitrogen enriched gas;
- a conduit configured to send oxygen enriched liquid or a liquid derived therefrom from the first column to a top condenser of the second column operating at a lower pressure than the first column, the second column having a bottom reboiler;
- a conduit configured to send liquid from the bottom of the second column to an intermediate point of the third column operating at a lower pressure than the second column;
- a conduit configured to send nitrogen enriched liquid from the top of the second column to the top of the third column;
- a conduit configured to remove oxygen rich liquid from the bottom of the third column;
- a pump configured to pressurize the oxygen rich liquid;
- a conduit configured to send pressurized oxygen rich liquid to the heat exchanger to be vaporized by heat exchange with air;
- a conduit configured to send oxygen enriched liquid from the top condenser of the second column to an intermediate point of the second column to be separated therein.
Dependencies are inferred from the claim text.