阅读说明：本技术 通过低温蒸馏分离空气的方法和装置 (Method and device for separating air by cryogenic distillation ) 是由 J-P·特拉尼耶 R·杜贝蒂尔格勒尼耶 M·罗谢雷斯 于 2021-05-19 设计创作，主要内容包括：在使用由在第一压力下运行的第一塔(101)和在第二压力下运行的第二塔(102)组成的塔系统通过低温蒸馏分离空气的方法中,将压缩到高于第一压力的第三压力的构成送往所述塔系统的空气的75％至98％的第一空气流(1)送往第一塔,将构成送往所述塔系统的空气的5％至25％的第二空气流(33)压缩到高于第二压力但低于第三压力的第四压力,送往第二塔,第三塔(103)分离富氩料流,且送往第二塔的空气(20)构成送往所述塔系统的总空气的10％至25％。(In a process for separating air by cryogenic distillation using a column system consisting of a first column (101) operating at a first pressure and a second column (102) operating at a second pressure, a first air stream (1) compressed to a third pressure higher than the first pressure and constituting 75% to 98% of the air sent to the column system is sent to the first column, a second air stream (33) constituting 5% to 25% of the air sent to the column system is compressed to a fourth pressure higher than the second pressure but lower than the third pressure and sent to the second column, the third column (103) separates an argon-rich stream, and the air (20) sent to the second column constitutes 10% to 25% of the total air sent to the column system.)

1. A method for separating air by cryogenic distillation using a column system consisting of a first column (101) operating at a first pressure and a second column (102) operating at a second pressure lower than the first pressure, the top of the first column being thermally coupled to the bottom of the second column, wherein:

i. compressing a first air stream (1) comprising 75% to 98% of the air sent to the system of columns to a third pressure higher than the first pressure, cooling and sending at the third pressure to a first adsorption unit (6) to purify from water and carbon dioxide, and sending a purified first stream to the first column and optionally to the second column;

compressing a second air stream (33) comprising 2% to 25% of the air sent to the column system to a fourth pressure between 1.2 and 2bar abs and higher than the second pressure but lower than the third pressure, preferably by direct contact cooling in an air cooling column (36), sent at the fourth pressure to a second adsorption unit (38) to purify water and carbon dioxide, and sending the purified second stream to the second column;

separating air in the first column to form an oxygen-rich liquid (41) and a nitrogen-rich gas;

sending an oxygen-rich liquid (41) and a nitrogen-rich liquid (49, 53) from the first column to the second column;

v. withdrawing from the column system a liquid (59) having an oxygen purity of greater than 99%, preferably 99.5%, compressing and then vaporizing by heat exchange with at least a portion of the first air stream (22, 29);

passing argon-rich gas (58) from the second column to a third column (103) and withdrawing an argon-rich stream from the top of the third column;

air (120) to the second column comprises 10% to 25% of the total air to the column system; and

the argon-rich fluid contains 20% to 80% of the argon contained in the first and second air streams (1, 33).

2. The method according to claim 1, wherein the argon-rich fluid contains 45% to 75% of the argon contained in the first and second air streams (1, 33).

3. The method according to claim 1 or 2, characterized in that the oxygen yield of the device is greater than 95%.

4. A method according to claim 1, 2 or 3, characterized in that the first air stream (1) is cooled by direct contact with a first water stream in a first cooling tower (4) and the second air stream (33) is cooled by direct contact with a second water stream in a second cooling tower (36), nitrogen (63) originating from the tower system being sent to a water cooling tower (91) and cooling water (94, 95) in the water cooling tower being sent to the first and second air cooling towers.

5. The method of claim 4 wherein the cooling water is cooled between the water cooling tower (91) and the second air cooling tower (36) such that the water delivered to the second air cooling tower is cooler than the water delivered to the first air cooling tower.

6. A method according to claim 4 or 5, wherein the air is cooled in the first air cooling tower (4) to a temperature which is at least 5 ℃, preferably at least 8 ℃ higher than the temperature to which the air is cooled in the second air cooling tower (36).

7. A method according to claim 4, 5 or 6, wherein the air is cooled in the first cooling tower (4) to a temperature which is at most 30 ℃, preferably at most 12 ℃ higher than the temperature to which the air is cooled in the second cooling tower (36).

8. Method according to one of the preceding claims, wherein the first purified stream is cooled upstream of said system of columns in a first heat exchanger (80) by heat exchange with a first nitrogen stream (65) originating from the system of columns, and the second purified stream is cooled upstream of said system of columns in a second heat exchanger (81) by heat exchange with a second nitrogen stream (67) originating from the system of columns.

9. The process according to claim 8, wherein the second purified stream is cooled in a second heat exchanger upstream of said column system by heat exchange only with a second nitrogen stream originating from the column system.

10. A method according to claim 8 or 9, wherein the second nitrogen stream (67) is introduced into the second heat exchanger (81) at a temperature at which it has not passed through another heat exchanger after leaving the column.

11. The method according to any one of the preceding claims, wherein the second air stream (33) is not expanded or pressurized between the second adsorption unit (36) and the second column (102).

12. The process according to any one of the preceding claims, wherein at least a portion of the first air stream is not expanded or pressurized between the first adsorption unit (6) and the first column (101).

13. The method according to any one of the preceding claims, wherein a portion (12) of the first air stream is pressurized and then expanded between the first adsorption unit and the first column (101).

14. Method according to one of the preceding claims, wherein a portion of the first air stream is expanded in a turbine and then sent in gaseous and/or liquid form to the first column (101).

15. The process according to any one of the preceding claims, wherein at least 14 mole% of the total air is sent to the second column.

16. The process according to any one of the preceding claims, wherein the purified second stream (40) is sent to the second column (102) for separation at the same column level as the oxygen-rich liquid stream originating from the first column or as the oxygen-rich liquid stream originating from the first column and vaporized (72) in the overhead condenser of the third column.

17. Apparatus for separating air by cryogenic distillation using a column system consisting of a first column (101) operating at a first pressure and a second column (102) operating at a second pressure lower than the first pressure, the top of the first column being thermally coupled to the bottom of the second column; a first adsorption unit (6); a second adsorption unit (36); means for passing a first air stream (1) compressed to a third pressure higher than the first pressure, constituting from 75% to 98% of the air sent to the column system, to cooling means and then to a first adsorption unit (6) at the third pressure to purify from water and carbon dioxide and means for passing the entire purified first stream to the first column and optionally to the second column; means for passing a second air stream, compressed to a fourth pressure between 1.2 and 2bar abs and higher than the second pressure but lower than the third pressure, constituting from 2% to 25% of the air sent to the column system, at the fourth pressure to a second adsorption unit to purify the water and carbon dioxide from the second air stream and means for passing the entire purified second stream to a second column, the first column containing heat and mass exchange means to separate the air to form an oxygen-rich liquid and a nitrogen-rich gas; means for passing the oxygen-rich liquid and the nitrogen-rich liquid from the first column to the second column; means for withdrawing a liquid (59) having an oxygen purity of greater than 99%, preferably 99.5%, from the column system; a pump for pressurizing such liquid; means for vaporizing the pressurized liquid by heat exchange with at least a portion of the first air stream and means for passing argon-rich gas (58) from the second column to the third column and means for withdrawing an argon-rich fluid from the top of the third column.