The invention relates to a plant for low-temperature air separation, having a rectification column system comprising a high-pressure column, a divided low-pressure column and a divided argon column, and a cold box system comprising a first cold box and a second cold box. The high-pressure column is arranged beneath the lower section of the low-pressure column. The high-pressure column together with the lower section of the low-pressure column is located in the first cold box, and the top section of the low-pressure column in the second cold box. It is proposed to arrange the base section of the argon column in the first cold box and the top section of the argon column in the second cold box, or vice versa. The present invention likewise provides a corresponding method.

The invention relates to a plant for low-temperature fractionation of air, having a rectification column system comprising a high-pressure column, a divided low-pressure column and an argon column, and a coldbox system comprising a first coldbox, a second coldbox and a third coldbox. The high-pressure column is disposed beneath the lower section of the low-pressure column. The high-pressure column together with the lower portion of the low-pressure column is disposed in the first coldbox, and the top portion of the low-pressure column in the second coldbox. It is proposed that the argon column or one or more sections of the argon column be disposed in the third coldbox. The pure oxygen column is disposed in the second coldbox. The present invention likewise provides a corresponding process.

A method and apparatus for producing compressed nitrogen and liquid nitrogen. A separation system has a high-pressure column, a low-pressure column with a top condenser and a main condenser. Air is compressed in an air compressor, purified, cooled in a heat exchanger and introduced into the high-pressure column. A first part of the gaseous top nitrogen from the low-pressure column becomes compressed nitrogen product. A second part of the gaseous top nitrogen is condensed in the condensing space of the top condenser and vapour is drawn off as a residual gas stream. The vapor is expanded in a first expansion machine. A second compressed nitrogen stream from the top of the high-pressure column is expanded in a second expansion machine and then drawn off as compressed nitrogen product. A part of the nitrogen condensed in the top condenser is drawn off as liquid nitrogen product.

A method for obtaining an air product from an air separation plant having a distillation column system and a tank system. The tank system includes a first tank and a second tank. Cryogenic liquid is withdrawn from the distillation column system, stored in the tank system, and used as the air product. The cryogenic liquid is supplied to the first tank and withdrawn from the second tank during a first period, and is supplied to the second tank and withdrawn from the first tank during a second period. The tank system has a third tank to which cryogenic liquid withdrawn from the first tank and the second tank is transferred unheated. The air product is withdrawn from the third tank in liquid state, vaporized and discharged. Alternatively, the cryogenic liquid can be withdrawn from the third tank and stored in the liquid state in a fourth tank.

An air separation device comprises: a main heat exchanger; a nitrogen rectification column; a nitrogen condensers disposed in a top portion of the nitrogen rectification column; a high-purity oxygen rectification column; and an oxygen evaporator disposed in a bottom portion of the high-purity oxygen rectification column. An oxygen-containing fluid discharged from an intermediate stage of the nitrogen rectification column is rectified in the high-purity oxygen rectification column and is concentrated in the bottom portion of the high-purity oxygen rectification column.

A process for cryogenic fractionation of air uses an air fractionation plant (100-400) comprises a rectification column system (10) having a high-pressure column (11) operated at a pressure level of 9 to 14.5 bar, a low-pressure column (12) operated at a pressure level of 2 to 5 bar, and an argon column (13). A recirculating stream is formed using a second top gas or a portion thereof, which is heated, compressed, cooled again, and after partial or complete liquefaction or in the unliquefied state is introduced partially or completely, or in fractions, into the first rectification column (11) and/or into the second rectification column (12).

A system and method of ultra-high purity (UHP) oxygen production from an argon and oxygen producing cryogenic air separation unit incorporating a dedicated methane rejection column or column section having a liquid to vapor (L/V) ratio lower than the L/V ratio in the associated argon rectifier is provided.

An apparatus for producing high-purity oxygen includes a heat exchanger for cooling feed air, a first rectification column, and a second rectification column. The first column reduces high-boiling-point impurities from the cooled air to produce an oxygen-containing liquid from a discharge portion. This liquid is then transferred to the second column, which reduces low-boiling-point impurities to yield the final high-purity oxygen product. A dedicated piping system connects the columns and features a branch. First piping, controlled by a first valve, directs the oxygen-containing liquid to the second column to regulate its flow rate. Second piping, controlled by a second valve, branches from the first. This arrangement allows for diversion of the liquid, enabling precise control over the properties of the feed to the second column. This control scheme ensures consistent product quality without reliance on expensive, real-time analytical instruments.