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AssigneeAir Products and Chemicals, Inc.
InventorsRakesh Agrawal, Ajay K. Modi, William T. Kleinberg
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The present invention relates an improvement to a cryogenic process for the separation of air which produces at least a nitrogen product and is carried out in a distillation column system having at least one distillation column from which the nitrogen product is produced. The distillation column of the distillation column system must comprise a rectifying section. In the process of the present invention, air is compressed, freed of impurities which will freeze out at cryogenic temperatures, cooled to near its dew point and fractionated in the distillation column system to produce the nitrogen product. The improvement is the operation of the distillation column such that the ratio of downward liquid to upward vapor flow rate (L/V) is no less than 0.65, preferably greater than 0.75, but less than 1.0 in the rectifying section of a distillation column from which the nitrogen product is produced. The flowrates are in moles per unit time.
A cryogenic process for the separation of air which produces at least a nitrogen product and is carried out in a distillation column system having at least one distillation column from which the nitrogen product is produced, wherein said distillation column, has at least the rectifying section, wherein, the feed thereto comprises nitrogen, oxygen, argon and carbon monoxide which is rectified to separate out nitrogen from the feed, characterized by operating the rectifying section of the distillation column from which the nitrogen product is produced at a ratio of downward liquid flow rate to upward vapor flow rate L/V) is greater than 0.65 and less than 1.0, thereby maximizing the separation between nitrogen and carbon monoxide and thus, producing a carbon monoxide-free nitrogen product.
Dependencies are inferred from the claim text.