Gas compressor, gas separation device in particular for air and method of separating a gaseous mixture, in particular air using at least three compressors and coolers alternating in series

摘要

The gas compressor has n stages (C1, C2, C3, C4, C5) connected in series where n is equal to at least 3, each stage is followed by a coolant (R1, R2, R3, R4, R5). At least two coolants have different pressure drops for the compressed gas, with the cooler with the lower pressure drop upstream of the cooler with the higher pressure drop. The cooler (R5) for the last stage of the compressor has a higher pressure drop than the first. The last stages of the compressor have a pressure drop higher than the first stages. At least two coolers have pressure drops differing by at least 30%, preferably at least 50% or even by at least 100%. Independent claims are also included for: (i) a gas separating device including at least one compressor as described above; (ii) an air separation unit comprising a cryogenic distillation unit with at least one distillation column, means of sending compressed air to a column in the unit, means of extracting a liquid from the column, and means of vaporizing the liquid by heat exchange with a compressed gas, where the gas has been compressed by at least one of the last stages of a compressor (R4, R5) as described above and/or the air is compressed in the compressor; and (iii) a method of separating a gas mixture by cryogenic distillation in a system of columns in which a gas intended for the columns or a gas from the columns is compressed in a compressor as described above and the gas leaving the last stage is at a pressure greater than 5 bars, preferably greater than 10 bars; compressing a first air flow to a first pressure; part of the air being suppressed to a second pressure greater than 10 bars; part of the air at the first pressure being sent to the distillation columns; extracting a liquid flow from the columns; vaporizing the liquid flow by heat exchange with the air at the second pressure; and compressing the air to the first and/or the second pressure in at least one compressor as described above.