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.

A method for operating a heat exchanger, in which a first operating mode is carried out in first time periods, and a second operating mode is carried out in second time periods that alternate with the first time periods; in the first operating mode a first fluid flow is formed at a first temperature level, is fed into the heat exchanger in a first region at the first temperature level, and is partially or completely cooled in the heat exchanger; in the first operating mode a second fluid flow is formed at a second temperature level, is fed into the heat exchanger in a second region at the second temperature level, and is partially or completely heated in the heat exchanger. A corresponding arrangement and a system with such an arrangement are also covered by the present invention.

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 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.

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 stackable modular element comprises a parallelepipedal caisson, the caisson comprising at least one layer of thermal insulation of thickness less than one-third of the width of the caisson, the layer of insulation covering at least the lateral and frontal faces of the caisson and surrounding at least one chamber having a parallelepipedal volume within the caisson, the chamber containing at least one body of material that permits the exchange of mass and/or of heat, the body being parallelepipedal in shape and filling at least part of the chamber, the chamber having an opening on the upper face and/or an opening on the lower face to allow fluid to be transferred to the body from outside the element and/or from the body to outside the element.

A heat exchanger assembly and a method for assembling the heat exchanger assembly is provided. The heat exchanger assembly comprises a first heat exchanger and a second heat exchanger, and a subcooler; a first heat exchanger cold box, for accommodating the first heat exchanger and heat exchange fluid pipelines, with a first opening being disposed in a side of the first heat exchanger cold box, and a first group of pipelines extending through the first opening; a second heat exchanger cold box, for accommodating the second heat exchanger and heat exchange fluid pipelines, with a second opening being disposed in a side of the second heat exchanger cold box, and a second group of pipelines extending through the second opening; a subcooler cold box, for accommodating the subcooler and heat exchange fluid pipelines, with a third opening and a fourth opening being disposed in a side of the subcooler cold box, and a third group of pipelines and a fourth group of pipelines extending through the third opening and the fourth opening respectively, wherein the first group of pipelines and the third group of pipelines are connected and encapsulated in a first thermally isolating casing, and the second group of pipelines and the fourth group of pipelines are connected and encapsulated in a second thermally isolating casing.

A method for operating a heat exchanger, in which a first operating mode is carried out in first time periods, and a second operating mode is carried out in second time periods that alternate with the first time periods; in the first operating mode a first fluid flow is formed at a first temperature, is fed into the heat exchanger in a first region at the first temperature, and is partially or completely cooled in the heat exchanger; in the first operating mode a second fluid flow is formed at a second temperature, is fed into the heat exchanger in a second region at the second temperature, and is partially or completely heated in the heat exchanger; and in the second operating mode the feeding of the first fluid flow and of the second fluid flow into the heat exchanger is partially or completely halted.

The present invention relates to a skid-mounted cold box and its prefabricated structure and assembly method. Each prefabricated structure includes a framework and a first panel that is used to enclose sides of the framework. Ring beams of two adjacent prefabricated structures are connected through bolts on site. A second panel connected through bolts encloses the gap between ring beams of the two adjacent prefabricated structures from sides. The present invention cancels all field welding seams and omits the field welding and nondestructive testing operations. The crane can be dismissed after the upper prefabricated structure of the cold box is lifted into place and bolts corresponding to columns on ring beams are connected. The present invention guarantees the connection strength of steel structures relying on bolt-based connection between ring beams and the second panel connected through bolts guarantees the airtightness of the cold box. This effectively reduces field assembly work and saves time and cost.

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.