阅读说明：本技术 用于通过低温蒸馏来分离空气的方法和设备 (Method and apparatus for separating air by cryogenic distillation ) 是由 伯诺瓦·达维迪安 于 2018-11-08 设计创作，主要内容包括：在通过低温蒸馏在塔系统中分离空气的方法中,该塔系统包括在第一压力下操作的第一塔(1)和在第二压力下操作的第二塔(2),富含氩的流(47)从第一塔的中间点被发送至第二塔的底部,并且富含氩的流(51)从第二塔的顶部被抽出,来自第一塔的富含氮的流(7,13,17)在压缩机(19)中被压缩,压缩后的流在膨胀步骤之后被发送至第二塔的顶部冷凝器(37),并且在冷凝器中汽化的流在涡轮机(41)中膨胀,在涡轮机中,流被至少部分地液化。(In a method for separating air by cryogenic distillation in a column system comprising a first column (1) operating at a first pressure and a second column (2) operating at a second pressure, an argon-rich stream (47) is sent from an intermediate point of the first column to the bottom of the second column and an argon-rich stream (51) is withdrawn from the top of the second column, the nitrogen-rich stream (7, 13, 17) from the first column is compressed in a compressor (19), the compressed stream is sent after an expansion step to a top condenser (37) of the second column and the stream vaporized in the condenser is expanded in a turbine (41) in which the stream is at least partially liquefied.)

1. A process for separating air by cryogenic distillation in a column system comprising a first column (1) operating at a first pressure and a second column (2) operating at a second pressure, the first pressure being substantially equal to the second pressure, wherein:

i) sending compressed, purified and cooled air to an intermediate point of the first column, withdrawing an oxygen-enriched liquid from the bottom of the first column and/or withdrawing an oxygen-enriched gas (45) from the first column, and withdrawing a nitrogen-enriched stream (7) from the top of the first column;

ii) sending an argon-rich stream (47) from an intermediate point of the first column to the bottom of the second column and withdrawing an argon-rich stream (51) from the top of the second column;

iii) the nitrogen rich stream (7, 13, 17) is compressed in a compressor (19) and the compressed stream is used to heat a bottom reboiler (31) of the first column, thereby producing an at least partially condensed nitrogen rich stream;

iv) dividing the nitrogen-enriched at least partially condensed stream into a first and a second portion (33, 35), sending the first portion to the top of the first column after the expansion step, and sending the second portion to the top condenser (37) of the second column after the expansion step, in which expansion step the second portion is at least partially vaporized to form an auxiliary stream (39), characterized in that

v) the auxiliary stream is expanded in a turbine (41) where it is at least partially liquefied and an at least partially liquefied stream (43) is sent to the top of the first column.

2. Method according to claim 1, wherein the auxiliary flow (43) is partially liquefied at the outlet of the impeller of the turbine (41) or even in the impeller of the turbine, for example so as to obtain an expanded auxiliary flow at the outlet of the impeller or in the impeller, the expanded auxiliary flow containing between 0.5% and 10%, preferably between 2% and 5%, of liquid.

3. A method as claimed in claim 1 or 2, wherein the auxiliary flow (43) is directly expanded in the turbine (41) without prior heating.

4. The method of one of claims 1, 2 or 3, wherein the nitrogen rich stream (17) is heated in a heat exchanger (15) located upstream of the compressor (19), the nitrogen rich compressed stream is cooled in the heat exchanger and then at least partially sent to the bottoms reboiler (31).

5. A method according to claim 4, wherein a portion (25) of the nitrogen-enriched compressed stream is expanded in a second turbine (27) and returned to the heat exchanger.

6. The method as claimed in one of the preceding claims, wherein the inlet temperature of the turbine (41) and/or the inlet temperature of the second turbine (27) and/or the inlet temperature of the compressor (19) is cryogenic.

7. The method of one of the preceding claims, wherein the argon-rich liquid stream is sent from the top of the second column (2) to the top of the first column (1).

8. The method of one of the preceding claims, wherein, in operation, no purge stream is withdrawn from the condenser (37) of the second column (2).

9. The process of one of the preceding claims, wherein after the expansion steps a first and a second portion (33, 35) of the at least partially condensed nitrogen-rich stream are at different pressures and/or temperatures, the second portion preferably being at a higher pressure than the first portion.

10. An apparatus for separating air by cryogenic distillation in a column system, the apparatus comprising: a first column (1) operating at a first pressure and having a bottom reboiler (31) and a second column (2) operating at a second pressure and having a top condenser (37), the first pressure being substantially equal to the second pressure; a compressor (19); a turbine (41); a conduit for sending compressed, purified and cooled air (3) to an intermediate point of the first tower; a conduit for withdrawing an oxygen-enriched liquid from the bottom of the first column and/or an oxygen-enriched gas (45) from the first column; and a conduit for withdrawing a nitrogen-rich stream (7) from the top of the first column and sending the stream to the compressor; a conduit for sending an argon-rich stream (47) from an intermediate point of the first column to the bottom of the second column; a conduit for withdrawing an argon-rich stream (51) from the top of the second column; a conduit for sending the nitrogen-rich stream compressed in the compressor to a bottom reboiler (31) of the first column to produce an at least partially condensed nitrogen-rich stream; means for dividing the at least partially condensed nitrogen-rich stream into first and second portions (33, 35); means for sending the first portion to the top of the first column after the expanding step; means for sending the second portion to a top condenser (37) of the second column after an expansion step in which the second portion is at least partially vaporized to form an auxiliary stream; means for sending the auxiliary flow (39) to the turbine, in which the auxiliary flow is at least partially liquefied; and means for sending an at least partially liquefied stream (43) to the top of the first column, potentially including a phase separator for separating the formed liquid and gas, so as to send the liquid and gas separately to the first column.

11. Plant according to claim 10, comprising a heat exchanger (15) upstream of the compressor (19) in which the nitrogen-rich stream is heated and means for sending the nitrogen-rich compressed stream and the nitrogen-rich stream to the heat exchanger, in which the nitrogen-rich compressed stream is cooled.

12. A plant as claimed in claim 10 or 11, comprising a second turbine (27) and means for sending to the second turbine a portion (25) of the compressed stream enriched in nitrogen, which portion is expanded in the second turbine (27).

13. The apparatus of one of claims 10 to 12, comprising means for sending an argon-rich liquid stream from the top of the second column to the top of the first column.

14. The apparatus of any one of claims 10 to 13, not comprising an air turbine.