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 method and apparatus for argon recovery in which an impure argon stream is separated from air within a cryogenic air separation unit having an argon rejection column and a reflux type argon condenser disposed internally within the lower pressure column. An impure argon stream is subsequently recovered from the argon rejection column and purified within an integrated adsorbent based argon refining and purification subsystem to produce product grade argon. The waste stream from the adsorbent based argon refining and purification subsystem is recycled back to the argon rejection column so as to improve the argon recovery.

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.

A method and apparatus for argon recovery in which an impure argon stream is separated from air within a cryogenic air separation unit having an argon rejection column and a reflux type argon condenser disposed internally within the lower pressure column. An impure argon stream is subsequently recovered from the argon rejection column and purified within an integrated adsorbent based argon refining and purification subsystem to produce product grade argon. The waste stream from the adsorbent based argon refining and purification subsystem is recycled back to the argon rejection column so as to improve the argon recovery.

A method and apparatus for argon rejection and recovery in which argon is separated from air within a cryogenic air separation plant having a divided wall argon rejection column arrangement and condensed using an argon condenser disposed internally within the lower pressure column. The divided wall argon rejection column arrangement may be an annular arrangement or a side-by-side arrangement (i.e. segmented or planar configuration). The resulting argon stream is subsequently rejected or recovered and optionally purified within an integrated adsorbent based argon refining and purification subsystem to produce product grade argon.

A method and apparatus for argon recovery in which an impure argon stream is separated from air within a cryogenic air separation unit having an argon rejection column and a reflux type argon condenser disposed internally within the lower pressure column. An impure argon stream is subsequently recovered from the argon rejection column and purified within an integrated adsorbent based argon refining and purification subsystem to produce product grade argon. The waste stream from the adsorbent based argon refining and purification subsystem is recycled back to the argon rejection column so as to improve the argon recovery.

A method and apparatus for increasing argon recovery in which an impure argon stream is separated from air within a cryogenic air separation unit and purified within an integrated, multi-stage pressure swing adsorption system to produce product grade argon with high argon recovery levels.

A method and apparatus for argon recovery in which an impure argon stream is separated from air within a cryogenic air separation unit having a divided wall argon rejection/rectification column. The resulting argon stream is subsequently recovered and purified within an integrated pressure swing adsorption system to produce product grade argon.

A method and apparatus for argon recovery in which an impure argon stream is separated from air within a cryogenic air separation unit having a divided wall argon rejection/rectification column. The resulting argon stream is subsequently recovered and purified within an integrated pressure swing adsorption system to produce product grade argon.

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.