A distillation column is constituted by a cylindrical shell which contains mass and heat transfer elements and which is closed at one end by a cap and at the other end by a domed bottom and a cylindrical skirt that has the same diameter as the cylindrical shell, is aligned coaxially with the cylindrical shell and is fixed to one end of the cylindrical shell so as to surround the domed bottom, forming a space between the bottom, the walls of the skirt and a base, the skirt comprising at least one opening to allow the passage of a flushing gas.

Disclosed in the present invention are a cold box steel structure and method for prefabricating and transporting the cold box steel structure. The cold box steel structure is a cuboid architecture, and has a long edge, a wide edge and a high edge of lengths L, W and H respectively, wherein L>W and L>H; the cold box steel structure comprises first and second rectangular base faces, each being an outer surface of the cuboid architecture comprising the long edge and the wide edge, and the cold box steel structure is prefabricated as two partial components taking a plane parallel to the rectangular base faces as a boundary; the total height of a first partial cold box steel structure component thereof, taking the first rectangular base face as a first transportation bottom face, is h1, and the total height of a second partial cold box steel structure component, taking the second rectangular base face as a second transportation bottom face, is h2; if the height difference between the transportation bottom face and the ground or a water surface is h, then (h1+h) corresponds to a transportation height of the first partial cold box steel structure component, and (h2+h) corresponds to a transportation height of the second partial cold box steel structure component; the transportation height of either of the cold box steel structure components should be smaller than a maximum permitted transportation height h.sub.max.

A purification system having pipelines arranged at different levels in a height direction is disclosed. The purification system can include: a first purifier and a second purifier disposed side by side symmetrically; an air input pipeline, an air output pipeline and a waste nitrogen input pipeline, wherein the air input pipeline, the air output pipeline and the waste nitrogen input pipeline are disposed at different heights, the gap between pairs of pipelines being determined so as to facilitate overhaul of three-stem valves, a value W being smaller than a value W when the air input pipeline, the air output pipeline and the waste nitrogen input pipeline are arranged in parallel on the ground, and the purification system further comprises: a three-stem valve platform formed by a framework structure in a number of levels, to facilitate overhaul of the three-stem valves.

A piping module is described which comprises at least two fluid connections or ports for connection to at least one main heat exchanger of an air fractionation plant, whereby the main heat exchanger becomes linked to at least two fluid lines in a warm part of the air fractionation plant. The piping module comprises at least two ports on the main compressor side, couplable to at least two fluid lines in the warm part of the air fractionation plant, and at least two ports on the main heat exchanger side, couplable to at least two fluid ports of the at least one main heat exchanger, and at least two fluid lines connecting the ports on the main compressor side to the ports on the main heat exchanger side. A corresponding air fractionation plant and a method for erecting such an air fractionation plant (100) are likewise described.

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 a low-temperature air separation in which an air separation unit is used comprising a first rectification column and a second rectification column. The first rectification column is operated at a first pressure level, and the second rectification column is operated at a second pressure level below the first pressure level. Fluid which is oxygen-enriched compared to atmospheric air is drawn from the first rectification column in the form of one or more first material flows. At least one fraction of the fluid which has been drawn from the first rectification column in the form of the one or more first material flows is heated in a heat exchanger; a fraction of the fluid which has been heated in the heat exchanger is compressed using a compressor and is returned to the first rectification column.

Disclosed herein is a modular process plant structural system which includes numerous modules, all ISO-certified under ISO 1496 and capable of holding within the entire module at least one chemical (or non-chemical) production plant piece of equipment, capable of individually being shipped or transported. The modules can be stacked vertically, horizontally, or mixed (both vertical and horizontal arrangement). The modules are pre-fabricated offsite, built with the desired equipment within the module, pre-plumbed with piping, instrumentation, and electrical wiring, and then the multiple modules are shipped multimodally as ISO 1496 containers to the desired location and assembled to form a plant. Generally, two or more modules are connected together to form a complete plant. The plant can be of any type, e.g., chemical, mechanical/production, thermal, and the like, or of any size, e.g., production, small, micro, or pilot plant scale. When no longer needed, the plant may be disassembled and reused at another site or facility.

An enclosure suitable for thermally insulating at least one distillation column comprising an elongate parallelepipedal framework and at least one part of a distillation column inside the framework, the enclosure or at least the lower part of the enclosure serving as support for the lifting means for installing elements in the column or for adding another part of the section of the column to that part of the column that is present in the enclosure or for adding another part of the enclosure.

A chamber for a distillation column that is to operate at a temperature below 0° C., comprises at least four walls, which in use are vertical, and a roof, the chamber being designed to contain at least one distillation column, at least one other element that is to operate at a cryogenic temperature, and insulation, at least one wall being convex.

An air separation unit using cryogenic distillation comprises a first column, a second column thermally linked to the first column, a first argon column, a second argon column, means for sending cooled, compressed and purified air to at least the first column, means for sending at least one fluid enriched in nitrogen from the first column to the second column and at least one fluid enriched in oxygen from the first column to the second column, means for sending a gas enriched in argon from the second column to a first end of the first argon column, means for sending gas from a second end of the first argon column to a first end of the second argon column, means for removing argon rich fluid from a second end of the second argon column, a pump, means for removing argon enriched liquid from the first end of the second argon column and sending it to the second end of the first argon column via the pump, the first end of the first argon column being raised above the ground by a first supporting structure, the pump being positioned within the first supporting structure, such that the pump is at least partially underneath the first end of the first argon column.