A process for the production of a liquid oxygen stream and a liquid hydrocarbon-rich stream by the cryogenic rectification of an inlet air stream, including dividing the inlet air stream into a first portion, and a second portion. Cooling the first portion, and the second portion against a cooled multicomponent refrigerant circuit, thereby producing a first cooled portion, and a second cooled portion. Condensing the first cooled portion, thereby producing a condensed first portion, then introducing the condensed first portion into one or more distillation columns. Expanding the second cooled portion in a turbo-expander, thereby producing an expanded second portion, then introducing the expanded second portion within the one or more distillation columns. Producing within the one or more distillation columns at least a waste nitrogen stream, a nitrogen enriched stream, and an oxygen enriched stream.

A method and apparatus for transferring a first liquid removed from an outlet of a first distillation column to an inlet of a second distillation column is provided. The second distillation column operates at a higher pressure than the first distillation column, and the inlet of the second distillation column is at higher elevation as compared to the outlet of the first distillation column. The method advantageously transfers the first liquid from the outlet to the inlet by mixing with a sufficient amount of a lower density second liquid that results in a mixed liquid having a reduced density as compared to the first liquid.

A method and apparatus for transferring a first liquid removed from an outlet of a first distillation column to an inlet of a second distillation column is provided. The second distillation column operates at a higher pressure than the first distillation column, and the inlet of the second distillation column is at higher elevation as compared to the outlet of the first distillation column. The method advantageously transfers the first liquid from the outlet to the inlet by mixing with a sufficient amount of a lower density second liquid that results in a mixed liquid having a reduced density as compared to the first liquid.

The invention proposes a process and an air separation plant comprising a rectification column system comprising a high-pressure column, a low-pressure column, a main heat exchanger, and a main air compressor. The total air supplied to the rectification column system is compressed in the main air compressor to a first pressure level. The high-pressure column is operated at a second pressure level, at least 3 bar below the first pressure level. A gaseous, nitrogen-rich fluid is removed from the high-pressure column and warmed up in the gaseous state without prior liquefaction. A first partial quantity of the gaseous, nitrogen-rich fluid is warmed to a first temperature level of −150 to −100° C., supplied at this first temperature level to a booster and compressed further to a third pressure level. The first partial quantity is then warmed to a second temperature level and discharged from the air separation plant.

In a method for separating air by cryogenic distillation, cooled air purified to remove water is sent to a first column operating at a first pressure, where it is separated into a nitrogen-enriched gas as an oxygen-enriched liquid; a gas enriched in argon relative to the air is withdrawn from the second column; at least a portion of the oxygen-enriched liquid is vaporized by heat exchange with the argon-enriched gas; and the vaporized, oxygen-enriched liquid is sent to an intermediate level of the second column.

An air separation plant for obtaining product containing argon by low temperature separation of compressed, cooled feed air. The air separation plant comprises a high-pressure column, a multi-part low-pressure column having a base segment and a head segment and a multi-part crude argon column having a base segment and a head segment. An oxygen-enriched flow is obtained from part of the feed air in the high pressure column, an argon-enriched flow is obtained from part of the oxygen-enriched flow in the low-pressure column, and an argon-rich flow is obtained from part of the argon-enriched flow in the crude argon column. Liquid flow is transferred from a lower region of the head segment of the low-pressure column and from a lower region of the base segment of the crude argon column into an upper region of the base segment of the low-pressure column.

A process for recovering at least one fluid (e.g. argon gas and/or nitrogen gas, etc.) from a feed gas (e.g. air) can provide an improved recovery of argon and/or nitrogen as well as an improvement in operational efficiency. Some embodiments can be adapted so that at least a portion of a mixed nitrogen-oxygen fluid is at least partially vaporized and fed to a low pressure column.

An air separation unit and associated method for separating air by cryogenic distillation using a distillation column system including a higher pressure column, a lower pressure column, an intermediate pressure kettle column, and an argon column arrangement is provided. The disclosed air separation unit and method is particularly suited for production of high purity nitrogen for electronics applications and includes nitrogen recycle circuit necessary to attain the higher purity nitrogen products. In addition to the intermediate pressure kettle column, the present air separation unit and associated method employs a once-through argon condenser, preferably disposed within the lower pressure column as well as a once-through kettle column reboiler, a once-through kettle column condenser.

An air separation unit and associated method for separating air by cryogenic distillation using a distillation column system including a higher pressure column, a lower pressure column, an intermediate pressure kettle column, and an argon column arrangement is provided. The disclosed air separation unit and method is particularly suited for production of high purity nitrogen for electronics applications and includes nitrogen recycle circuit necessary to attain the higher purity nitrogen products. In addition to the intermediate pressure kettle column, the present air separation unit and associated method employs a once-through argon condenser, preferably disposed within the lower pressure column as well as a once-through kettle column reboiler, a once-through kettle column condenser.

The invention proposes a process and an air separation plant comprising a rectification column system comprising a high-pressure column, a low-pressure column, a main heat exchanger, and a main air compressor. The total air supplied to the rectification column system is compressed in the main air compressor to a first pressure level. The high-pressure column is operated at a second pressure level, at least 3 bar below the first pressure level. A gaseous, nitrogen-rich fluid is removed from the high-pressure column and warmed up in the gaseous state without prior liquefaction. A first partial quantity of the gaseous, nitrogen-rich fluid is warmed to a first temperature level of 150 to 100 C., supplied at this first temperature level to a booster and compressed further to a third pressure level. The first partial quantity is then warmed to a second temperature level and discharged from the air separation plant.