A method for improving the capacity of an existing air separation unit employing a lost air turbine is provided in which the capacity is increased by operating the existing air separation unit as previously operated, with the exception of collecting the lost air from the lost air turbine, and instead of venting said lost air to the atmosphere, the lost air is compressed in a supplemental air compressor and returned to the air separation unit at a location downstream a front-end purification unit and upstream a booster. This setup advantageously allows for increased production without having to adjust the sizing of the front-end purification unit or main air compressor.

A method for improving the capacity of an existing air separation unit employing a lost air turbine is provided in which the capacity is increased by operating the existing air separation unit as previously operated, with the exception of collecting the lost air from the lost air turbine, and instead of venting said lost air to the atmosphere, the lost air is compressed in a supplemental air compressor and returned to the air separation unit at a location downstream a front-end purification unit and upstream a booster. This setup advantageously allows for increased production without having to adjust the sizing of the front-end purification unit or main air compressor.

A liquefier device which may be a retrofit to an air separation plant or utilized as part of a new design. The flow needed for the liquefier comes from an air separation plant running in a maxim oxygen state, in a stable mode. The three gas flows are low pressure oxygen, low pressure nitrogen, and higher pressure nitrogen. All of the flows are found on the side of the main heat exchanger with a temperature of about 37 degrees Fahrenheit. All of the gasses put into the liquefier come out as a subcooled liquid, for storage or return to the air separation plant. This new liquefier does not include a front end electrical compressor, and will take a self produced liquid nitrogen, pump it up to a runnable 420 psig pressure, and with the use of turbines, condensers, flash pots, and multi pass heat exchangers. The liquefier will make liquid from a planned amount of any pure gas oxygen or nitrogen an air separation plant can produce.

The invention relates to a method for separating air by cryogenic distillation in a column system, comprising a first column operating at a first pressure and a second column operating at a second pressure, in which an argon-enriched flow is sent from an intermediate point of the first column to the tank of the second column and an argon-rich flow is drawn off at the top of the second column, wherein a nitrogen-enriched flow of the first column is compressed in a compressor, the compressed flow is sent to a head condenser of the second column after an expansion step and the vaporized flow is expanded in the condenser in a turbine where it at least partially liquefies.

A method for improving the capacity of an existing air separation unit employing a lost air turbine is provided in which the capacity is increased by operating the existing air separation unit as previously operated, with the exception of collecting the lost air from the lost air turbine, and instead of venting said lost air to the atmosphere, the lost air is compressed in a supplemental air compressor and returned to the air separation unit at a location downstream a front-end purification unit and upstream a booster. This setup advantageously allows for increased production without having to adjust the sizing of the front-end purification unit or main air compressor.

A method for improving the capacity of an existing air separation unit employing a lost air turbine is provided in which the capacity is increased by operating the existing air separation unit as previously operated, with the exception of collecting the lost air from the lost air turbine, and instead of venting said lost air to the atmosphere, the lost air is compressed in a supplemental air compressor and returned to the air separation unit at a location downstream a front-end purification unit and upstream a booster. This setup advantageously allows for increased production without having to adjust the sizing of the front-end purification unit or main air compressor.

The object of the present invention is to provide a different solution for revamping existing producing apparatuses so as to increase the production of low pressure pure nitrogen while controlling as far as possible the capital and operation expenditures. The revamping solution comprises increasing the diameter and/or height of a pure nitrogen column to thereby improve the production capacity thereof; choosing to switch the conduits where the waste liquid nitrogen and pure liquid nitrogen are passed through in the subcooler according to the increment of the low pressure pure nitrogen production; adding an additional heat exchanger to conduct a heat exchange between a portion of the medium pressure air and the increased low pressure pure nitrogen; or simultaneously switching the main parts of the conduits which transfer the pure liquid nitrogen and waste liquid nitrogen from a first column of higher pressure to a second column of lower pressure while performing the above revamping. The stepwise revamping solution of the present invention can be used not only to control the cost but also increase the low pressure pure nitrogen production while ensuring a stable operation of the air separation unit.

The invention relates to a column for separating air by means of cryogenic distillation, said column comprising a shell and at least four distillation segments, including at least a first intermediate distillation segment of the low-pressure column, which is surrounded by an auxiliary shell around which a space is defined that is divided into a lower section and an upper section along the radius of the column, the intermediate segment(s) being located in an intermediate part of the low-pressure column, the capacity of the first intermediate segment being greater than that of at least one adjacent segment, and an opening being disposed in the shell between two adjacent segments, which opening can be sealed if the column is to form part of an argon production device.

The invention relates to a method for constructing or altering a matter- and/or heat-exchange device, said mass- and/or heat-exchange device comprising an assembly of at least one first and one second stackable modular elements (A, B, C, D, E, F, G, H, I, J, K, L), in which the first element is secured over the second element or the second element is secured below the first element in a sealed manner, such that a fluid can flow from the body of the first element to the body of the second element and/or from the body of the second element to the body of the first element.

A system and method for flexible production of argon from a cryogenic air separation unit is provided. The cryogenic air separation unit is capable of operating in a no-argon or low-argon mode when argon demand is low or non-existent and then switching to operating in a high-argon mode when argon is needed. The recovery of the argon products from the air separation unit is adjusted by varying the percentages of dirty shelf nitrogen and clean shelf nitrogen in the reflux stream directed to the lower pressure column. The cryogenic air separation unit and associated method also provides an efficient argon production/rejection process that minimizes the power consumption when the cryogenic air separation unit is operating in a no-argon or low-argon mode yet maintains the capability to produce higher volumes of argon products at full design capacity to meet argon product demands.