Process and installation for the production of gaseous oxygen under pressure
AssigneeL'Air Liquide, Societe Anonyme pour l'Etude et l'Exploitation des Procedes Georges Claude
InventorMaurice Grenier
Life of this patent
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Abstract
An air separation process of the "pumped" type, in which liquid oxygen is removed from a double distillation column and is pumped to a higher production pressure and then vaporized under that pressure. The incoming air is divided into several streams. A first stream is compressed to the medium pressure, cooled and sent to the double distillation column (7). A second stream is compressed above about 25 bars, but below its condensation pressure during vaporization of the liquid oxygen under pressure, then cooled to an intermediate temperature, at which a portion of the air continues its cooling and is liquified (in 20A), then expanded (in 21A) and sent to the double column, while the rest is work expanded (in 4). Use in large size installations for the production of oxygen.
Claims12
In a process for the production of gaseous oxygen under pressure, of the type in which:
- air is distilled in an installation with a double distillation column (7;
- 44) which comprises a medium pressure column (8;
- 45) operating under a medium pressure, a low pressure column (9;
- 46) operating under a low pressure, and a heat exchange line (6;
- 47) to place the air to be distilled in heat exchange relation with products withdrawn from the double column;
- liquid oxygen is withdrawn from the low pressure column;
- the withdrawn liquid oxygen is brought to an oxygen vaporization pressure of at least about 13 bars, and it is vaporized and reheated under said vaporization pressure, by heat exchange with the air to be distilled in the course of cooling;
- the improvement comprising compressing a first fraction of the air to be distilled to a first pressure adjacent the medium pressure, cooling the compressed first fraction of air to the vicinity of its dew point in the heat exchange line (6;
- 47), and sending the cooled compressed first fraction of air to the double column (7;
- 44);
- compressing a second fraction of the air to be distilled to a high air pressure at least equal to about 25 bars but lower than the condensation pressure of the air by heat exchange with the oxygen in the course of vaporization under said oxygen vaporization pressure, cooling and partially liquefying the compressed second fraction of air, then expanding and introducing the compressed second fraction of air into the double column;
- withdrawing a portion of air under the high pressure from the heat exchange line (6;
- 47) at an intermediate cooling temperature, expanding the latter air to the medium pressure in a first expansion turbine (4;
- 51), then sending the latter expanded air to the double column (7;
- 44);
- and withdrawing at least one liquid product (in 33, 34;
- 72, 72A) from the installation.
In an installation for the production of gaseous oxygen under pressure, comprising:
- a double air distillation column (7;
- 44) which comprises a medium pressure column (8;
- 45) operating under a medium pressure, and a low pressure column (9;
- 46) operating under a low pressure;
- a heat exchange line (6;
- 47) to place the air to be distilled in heat exchange relation with products from the double column;
- means to withdraw liquid oxygen from the low pressure column;
- and means (12;
- 49) to bring this liquid oxygen to an oxygen vaporization pressure of at least about 13 bars, the heat exchange line comprising means to place the liquid oxygen under said vaporization pressure in heat exchange relation with air to be distilled in the course of cooling;
- the improvement which comprises:
- first compression means (1;
- 41) to compress a first fraction of air to be distilled to a first pressure adjacent the medium pressure, and passages (20;
- 62) of the heat exchange line being connected at one end to these first compression means and at another end to the double column (7;
- 44);
- second compression means (1, 5;
- 41, 42, 50;
- 41, 42, 73, 50) to compress a second fraction of the air to be distilled to a high air pressure equal to at least about 25 bars but lower than the condensation pressure of the air by heat exchange with the oxygen in the course of vaporization under said vaporization pressure;
- the heat exchange line comprising high pressure air passages (20A;
- 64) to cool said second air fraction to an intermediate temperature and to further cool and liquify a portion of this second fraction, and the installation comprising means (21A;
- 68, 69) for expansion of this liquified portion, connected to the double column;
- a first expansion turbine (4;
- 75) whose intake is connected to the high pressure air passages (74) and whose output is connected to the double column (7;
- 74);
- and
- means (72, 72A) to withdraw at least one liquid product from the installation.
Dependencies are inferred from the claim text.