| 摘要 |
The invention relates to a method for producing air products by means of low-temperature separation of air in a distillation column system (7) of an air separation plant. Said system comprises a high-pressure column (71) and a low-pressure column (72), wherein the overall total amount of air used in the method is compressed in a main compressor (2) to a main compressor pressure, which is at least 4 bars higher than an operating pressure at which the high-pressure column (71) is operated. A first portion of the total air amount compressed to the main compressor pressure is conveyed to the hot side of a main heat exchanger (6), and is cooled therein, is expanded in an expansion machine (12) and fed into the high-pressure column (71). A second portion of the total air amount compressed to the main compressor pressure is cooled in the main heat exchanger (6), is expanded, and is fed into the distillation column system (7). According to the invention the method is carried out in a first and in a second operating mode, subject to a liquid product quantity of at least one air product to be extracted from the air separation plant in a liquid state, wherein a generator turbine (30) is used, in which in the second operating mode a third portion of the total amount of air is expanded and blown into the atmosphere at a quantity that is higher than the quantity in the first operating mode. In the second operating mode, at least one liquid air product of the air separation plant is extracted at a greater liquid product quantity than in the first operating mode. The first portion of the total amount of air is conveyed to the expansion machine (12) at most at a pressure, at which said first portion is conveyed to the hot side of the main heat exchanger (6). The invention further relates to an air separation plant configured for carrying out such a method. |
