| 摘要 |
Separation of air is obtained by vaporization of pressurised liquid in an exchange line of a air separation unit by heat exchange with a compressed gas at a cryogenic temperature. The process is carried out in an installation comprising a double or triple air separation column operating at a high pressure and with an exchange line, in which (1) all the air is raised to high pressure, greater by at least 5 bars to the mean pressure, and purified; (2) part of the air flow is cooled in the exchanger and divided into two fractions; (3) each fraction is expanded in a turbine; (4) the inlet pressure of each turbine is greater by 5 bars to the mean pressure; (5) the exhaust pressure is equal to the mean pressure; (6) part of the air expanded in one of the turbines is sent to the double or triple column; (7) a cold compressor, mechanically connected to one of the expansion turbines aspirates air, which has been cooled in the heat exchanger, and exhausts air at a temperature higher than the inlet temperature, the fluid thus compressed being re-introduced in the exchanger in which part condenses; (8) at least one liquid from the column is vaporized in the heat exchanger. The turbine not coupled to the cooled compressor is coupled to a compressor followed by a refrigerant, and, optionally, the temperature of aspiration of the cold compressor approximates to the temperature of vaporization of the liquid. An independent claim is also included for the installation of the process. |
