Patent Application
20200132368
This application claims the benefit of priority under 35 U.S.C. § 119 (a) and (b) to Chinese patent application No. CN201821756409.6, filed Oct. 29, 2018, the entire contents of which are incorporated herein by reference.
The present invention relates to an apparatus for the distillation of air by cryogenic distillation.
It is common to separate air in a double distillation column including a first column operating at a medium pressure and a second column operating at a low pressure. A liquid enriched in oxygen is sent from the first column to the second column. A liquid enriched in nitrogen is sent from the first column to the second column. One or both of these liquids may be cooled in a heat exchanger called a subcooler by heat exchange with a gaseous nitrogen stream from the low pressure column.
The second column is placed above the first column and generally forms a common structure called the double distillation column.
Where it is required to separate argon, an argon column is provided taking an argon enriched gas from an intermediate region of the low pressure column. Pure argon can then be removed from the top of the argon column.
Each of the columns requires to be insulated in an enclosure containing an insulating material such as perlite.
Generally in the past, the subcooling heat exchanger has been provided within a separate enclosure from the columns, being contained in the same enclosure as the main heat exchanger which cools the feed air. This means that complex assembly work has to be done on site in order to connect the subcooling heat exchanger to the columns. This is expensive and time-consuming.
According to the invention, there is provided an apparatus for the distillation of air by cryogenic distillation comprising an enclosure, a first distillation column operating at a first pressure, a second distillation column operating at a second pressure, the second distillation column being placed above the first distillation column and forming therewith a double column, a subcooling heat exchanger for cooling at least one liquid from the first distillation column upstream of the second distillation column and for warming a gaseous nitrogen stream from the second distillation column, an argon column for separating an argon enriched stream from the second distillation column and for producing an argon rich stream, the first and second columns, the argon column and the subcooling heat exchanger being within the enclosure and the subcooling heat exchanger being placed directly underneath the first distillation column or the argon column, within a supporting structure.
This apparatus is particularly compact.
Preferably, embodiments of the invention may also include the following features:
The invention will be described in greater detail with reference to the figures, which show a simplified layout of the apparatus.
Further features, advantages and possible applications of the invention are apparent from the following description of working and numerical examples and from the drawings. All described and/or depicted features on their own or in any desired combination form the subject matter of the invention, irrespective of the way in which they are combined in the claims the way in which said claims refer back to one another.
In
The second column 4 is placed above the first column 2 and forms a common structure called the double distillation column, the nitrogen from the first column being condensed in a bottom reboiler condenser 3 which provides reboil to the second column.
An argon column 6, taller than the double column 2,4, is provided taking an argon enriched gas from an intermediate region of the low pressure column 4 as feed. Pure argon can then be removed from the top of the argon column 6. Bottom liquid from the argon column 6 is sent back to the second column 4.
The subcooling heat exchanger 12 is placed directly underneath the first column 2 within a supporting structure which maintains the double column 2,4. In this way the total height of the heat exchanger 12 within the supporting structure 14 and the double column 2,4 is substantially the same as that of the argon column 6. In this way the enclosure 10 containing the columns 2,4,6 and the subcooler 12 can be more compact.
The top of the second column 4 is at the same level as the top of the top condenser 8 of argon column 6.
The base of the argon column 6 is substantially at the same level as the middle of supporting structure 14, the argon column being itself maintained above ground 16 by another supporting structure 14A.
The enclosure 10 contains an insulating material such as perlite.
The supporting structure 14 supports columns 2,4 and possibly also the subcooler 12.
In
The second column 4 is placed above the first column 2 and forms a common structure called the double distillation column, the nitrogen from the first column being condensed in a bottom reboiler condenser 3 which provides reboil to the second column.
An argon column 6, in this case shorter than the double column 2,4, is provided taking an argon enriched gas from an intermediate region of the low pressure column 4 as feed. The height of the argon column 6 may be equal to that of the low pressure column 4. Pure argon can then be removed from the top of the argon column 6. Bottom liquid from the argon column 6 is sent back to the second column 4.
The subcooling heat exchanger 12 is placed directly underneath the argon column 6 within a supporting structure 14 which maintains the argon column 6. In this way the total height of the heat exchanger 12 within the supporting structure 14 and the argon column 6 is substantially the same as that of the double column 2,4. In this way the enclosure 10 containing the columns 2,4,6 and the subcooler 12 can be more compact.
The top of the second column 4 is at the same level as the top of the top condenser of argon column 6.
The base of the argon column 6 is substantially at the same level as the top of the first column 2, the argon column being itself maintained above ground 16 by supporting structure 14.
The enclosure 10 contains an insulating material such as perlite.
The supporting structure 14 supports argon column 6 and possibly also the subcooler 12.
Another supporting structure 14A supports the double column 2,4 above ground 16.
While the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art in light of the foregoing description. Accordingly, it is intended to embrace all such alternatives, modifications, and variations as fall within the spirit and broad scope of the appended claims. The present invention may suitably comprise, consist or consist essentially of the elements disclosed and may be practiced in the absence of an element not disclosed. Furthermore, if there is language referring to order, such as first and second, it should be understood in an exemplary sense and not in a limiting sense. For example, it can be recognized by those skilled in the art that certain steps can be combined into a single step.
The singular forms “a”, “an” and “the” include plural referents, unless the context clearly dictates otherwise.
“Comprising” in a claim is an open transitional term which means the subsequently identified claim elements are a nonexclusive listing (i.e., anything else may be additionally included and remain within the scope of “comprising”). “Comprising” as used herein may be replaced by the more limited transitional terms “consisting essentially of” and “consisting of” unless otherwise indicated herein.
“Providing” in a claim is defined to mean furnishing, supplying, making available, or preparing something. The step may be performed by any actor in the absence of express language in the claim to the contrary.
Optional or optionally means that the subsequently described event or circumstances may or may not occur. The description includes instances where the event or circumstance occurs and instances where it does not occur.
Ranges may be expressed herein as from about one particular value, and/or to about another particular value. When such a range is expressed, it is to be understood that another embodiment is from the one particular value and/or to the other particular value, along with all combinations within said range.
All references identified herein are each hereby incorporated by reference into this application in their entireties, as well as for the specific information for which each is cited.
| Number | Date | Country | Kind |
|---|---|---|---|
| CN 201821756409.6 | Oct 2018 | CN | national |
