AIR SEPARATION PLANT AND PROCESS OPERATING BY CRYOGENIC DISTILLATION

摘要

An air separation plant comprises at least two air compressors (1, 3A, 3B) receiving air at substantially atmospheric pressure, at least two air purification units (5A, 5B, 5C) and one or more cold boxes (25, 27), at least one compressor being connected to each of the purification units so as to send compressed air thereto, the purification units being connected to the cold box or boxes, a first compressor (1) being designed to produce air at a first pressure and to send the air at the first pressure to a first purification unit (5A), the first purification unit being connected to one or more high-pressure air lines (21, 23) of the or the first cold box, a second compressor (3B, 3C) being designed to produce air at a second pressure and to send all the air at the second pressure to a second purification unit (5B, 5C), and the second purification unit being connected to one or more medium-pressure air lines (17, 19) of the or the first cold box, a means (28) for modifying the operation of the second compressor in order to increase the pressure of the air produced to a pressure above the second pressure, the second pressure being below the first pressure, and the delivery side of the second compressor being connected to the high-pressure air line or lines of the or the first cold box through the second purification unit so as to send air there to at the pressure above the second pressure.