STRUCTURAL PANEL INTENDED TO FORM PART OF A COLD BOX OF A SEPARATION DEVICE

Abstract

Structural panel intended to form part of a cold box of a low-temperature distillation separation device, comprising at least one chamber made from carbon steel or chrome and nickel alloy steel, with a rectangular or non-rectangular, optionally isosceles, trapezoid cross-section, having a roof and/or bottom sloping at an angle of between 45° and 60° relative to the panel and one open face, the open face being positioned on the inner face of the structural panel.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority under 35 U.S.C. § 119 (a) and (b) to French patent application No. FR 1904118, filed Apr. 17, 2019, the entire contents of which are incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to a structural panel intended to form part of a cold box of a separation device and a cold box comprising such a panel.

BACKGROUND OF THE INVENTION

Conventionally, low-temperature or cryogenic-temperature distillation separation units comprise at least one distillation column arranged in an insulating structure known as a cold box (CB). The cold box is a metal enclosure that generally has a substantially parallelepipedal shape so as to form a predetermined insulation thickness around the column and its pipes. The insulation material used is generally perlite.

A low temperature is a temperature below 0° C., or even below −100° C.

The present invention relates to the inner chambers of a CB, housing at least one accessory selected from the following group: manual valve, automatic valve, flow meter, valve shutter, sensor or other instrumentation means. The accessory generally requires access for maintenance operations but is connected to the pipes of the distillation columns and/or heat exchangers of a low-temperature or cryogenic-temperature distillation separation device. The mixtures to be separated comprise air or air gases for ASUs (double main column or argon column) and also a synthesis gas comprising hydrogen and carbon monoxide, an ammonia synthesis gas comprising nitrogen and hydrogen, a mixture comprising carbon dioxide, oxygen and nitrogen or a mixture comprising carbon dioxide and hydrogen.

The cold boxes can be stick-built units or package units.

Package Units

In order to limit the assembly costs on the installation site, and especially to control the manufacturing quality, one of the methods commonly used is to pre-assemble the column with pipe elements and accessories in the manufacturer's workshop and insert it into a metal enclosure with a cross-section incorporating the future insulation thicknesses all around the column as described in EP 0 913653 A1. This assembly, pre-assembled in a horizontal position, known as a package unit, is then transported and installed on the final construction site.

The package unit assembly option described above nonetheless has the drawback of considerably increasing the weight of the enclosure in order to ensure the mechanical stability thereof during the erection phase for moving the package unit from a horizontal position to a vertical position. In addition to their weight, which significantly increases the transport costs, these package units are also faced, largely due to their considerable volume, with serious problems limiting their transport (fitting under or over bridges or through tunnels, around bends, under electricity lines, etc.).

SUMMARY OF THE INVENTION

According to certain embodiments of the invention, when the CBs are prefabricated as package(s) (comprising one or more sub-packages), both in a workshop and directly on the installation site, at least one accessory of the CB selected from the following group: manual valve, automatic valve, flow meter, valve shutter, sensor or other instrumentation means, etc. requiring its installation in a separate chamber fastened to the inner walls of the CB, is installed in an accessory chamber, parallelepipedal in shape but with roof and/or bottom faces sloping at between 45° and 60° to the horizontal in order to prevent the perlite from banking and a loss of performance of the insulation. The chamber is in turn installed in the package in order to make it possible to insulate it thermally, generally with rock wool, once installation on the construction site is complete and before the starting of the CB, which in turn is filled with a powdered insulation material such as perlite. This installation in dedicated chambers, making it possible to be isolated from the perlite, ensures access by making it possible to easily remove the rock wool insulation with which they are filled, in the event of subsequent operations for inspection or maintenance for example of the elements or accessories that they contain.

In this type of design, the assembly and production of the accessory chambers, as it is carried out in a horizontal position in the workshop, does not make the manufacturing of the package units more complex. The constraints generated by this design are mainly the additional cost of the material of the enclosure and the limited transportability.

Stick-Built Units

For stick-built design, the CBs are entirely assembled on the construction site. That is, all of the pipes of the CB must be installed one by one and connected to the vertical distillation column and/or to other columns, to cryogenic exchangers and/or to pumps and/or to turbines at a height ranging from ground level to approximately 60 m. Similarly the accessories (manual or automatic valves, flow meters, valve shutters, miscellaneous sensors, etc.) must be connected to these pipes one by one, which requires a lot of manpower and a large quantity of scaffolding and does not facilitate worker productivity.

These accessory chambers are also produced on the construction site. These accessory chambers can be located on any inner face of the CB at a height varying from ground level to approximately 60 m. These chambers are the same type as those installed in the package units and house the accessories described previously.

In this type of CB assembly, one of the challenges is to significantly reduce the installation time and planning risks of the CB by limiting the construction activities as much as possible while guaranteeing a level of quality comparable to the manufacturing of the package units in the workshop.

To this end, measures are taken to offer a high level of prefabrication of the carbon steel jacket structures of the CB. This involves the prefabrication in panel form of the various structural elements of the CB. These various panels can be rectangular and flat (flat panels), angled (corner panels) and also in the form of a portion of a sector of a circle (shell panels), and are described for example in US20060162379A1.

During the design of a stick-built cold box, the present invention firstly proposes designing a chamber housing the various accessories (manual or automatic valves, flow meters, valve shutters, miscellaneous sensors, etc.) and having it manufactured in the manufacturer's workshop.

Secondly, for even greater optimization of the on-site construction phase, the distillation column can be partially provided, in the manufacturer's workshop, with some of its pipes, obviously such as those that will have to be connected to the accessory chambers in order to fully restore the pipe network once the accessory chamber fastened to its structural panel has been put in place and after welding of the pipe interfaces of said chamber with the pipe spools installed in advance on the distillation column.

This chamber will then be sent, as will the distillation column provided with some of its pipe spools, to the construction site.

This chamber will have at least one open face that will subsequently be in contact with the structural panel of the CB.

This chamber, the structure of which will preferably be made from carbon or stainless steel, will preferably by provided with handling means, known as lifting lugs, so that it can be handled in order to connect it by welding or bolting to the inner face of a structural panel of the prefabricated CB.

The chamber is preferably connected to the structural panel on the ground, at breast height or a height only requiring a small mobile scaffold, before final lifting and positioning of the structural panel around the distillation column in order to minimize the risks and reduce operations at height, which are generally very costly.

Pipe spools comprising their associated accessories as described previously will also be installed in this prefabricated chamber.

These pipe spools, in this prefabricated chamber, will have permanent or temporary supports for securing the pipe spools and accessories during the transport and handling phase with a view to connecting the panel, and during the handling of the panel and its final positioning around the distillation column.

The present invention aims to provide assembly means that make it possible to both maintain the quality criteria relating to the workshop pre-assembly of the elements requiring strict quality control (typically the entire cryogenic part), and greatly limit the problems and costs relating to transport to the construction site and facilitate the installation on the construction site of the stick-built cold boxes.

Such a method, which no longer takes into consideration, for its pre-assembly and transport, the volume of insulation necessary for the column or the enclosure that contains the insulation, makes it possible to increase the options for transporting a sub-assembly of a cryogenic unit such as a distillation column by reducing the overall dimensions while allowing a high level of controlled prefabrication in the workshop.

According to one object of the invention, a structural panel intended to form part of a cold box of a low-temperature distillation separation device is provided, comprising at least one chamber made from carbon steel or stainless steel, for example comprising chrome and nickel, with a rectangular or non-rectangular, optionally isosceles, trapezoid cross-section, having a roof and/or bottom sloping at an angle of between 45° and 60° relative to the panel and one open face, the open face being positioned on the inner face of the structural panel.

According to other optional features:

• • the panel contains at least one accessory selected from the following group: manual valve, automatic valve, flow meter, valve shutter, sensor or other instrumentation means, as well as a pipe spool connected to the accessory;
  • the chamber comprises at least one means for handling the chamber and at least one permanent or temporary support to support the at least one pipe spool and/or the at least one accessory during the transport phases and the connection to the structural panel;
  • the chamber is fastened to the panel by welding or bolting, preferably on the ground before lifting;
  • the chamber comprises at least one perforated face covered with a material that is impermeable to a particular insulation material, for example to perlite, but permeable to a flushing gas; and/or
  • the chamber contains rock wool and/or aerogel.

According to another aspect of the invention, a cold box of a low-temperature distillation separation device is provided, comprising at least four vertical walls, at least one of which consists of or comprises a panel as described above, the cold box being filled with insulation material and containing at least one element of the device intended to operate at a low temperature, or at a cryogenic temperature (e.g., a temperature at or below −50° C.).

The cold box preferably contains at least one distillation column and/or at least one heat exchanger.

According to another object of the invention, a method for assembling a cold box of a low-temperature distillation separation device is provided, comprising at least four panels to be arranged vertically around one element intended to operate at a low temperature, or at a cryogenic temperature, in which the wall of at least one panel is provided with a chamber made from carbon steel or chrome and nickel alloy steel, with a rectangular or non-rectangular, optionally isosceles, trapezoid cross-section, having a roof and/or bottom sloping at an angle of between 45° and 60° relative to the panel and one open face, by fastening the open face to the inner face of the structural panel.

The chamber can be fastened to the panel in a workshop or on the cold box installation and/or construction site.

Preferably, the panels are fastened together once the chamber is fastened to the panel.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features and advantages of the invention will become apparent from the description hereinafter of embodiments, which are given by way of illustration but without any limitation, the description being given in relation with the following attached figures:

FIG. 1 is a vertical cross-section of a chamber fastened to a panel according to the invention.

FIG. 2 is an exploded view of a cold box comprising two panels according to the invention.

FIG. 3 illustrates the chamber in more detail.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 illustrates a panel 5 of a cold box of a distillation air separation device; the cold box can contain a column and/or a heat exchanger. An element 3 to be insulated is illustrated as being surrounded with perlite 15. Fastened to the inner face of the panel 5 is a chamber 1 made from carbon steel or chrome and nickel alloy steel (stainless steel). It has a roof at an angle of 60° relative to a vertical plane, which is the plane of the panel 5. The bottom is sloped at 45° relative to the panel. Other angles between 45° and 60° are possible.

This serves to prevent the perlite 15 surrounding it from banking. The chamber 1 has one open face, the open face being positioned on the inner face of the structural panel 5. Inside the chamber 1 is at least one accessory 9 that can be a manual valve, an automatic valve, a flow meter, a valve shutter or a sensor. The accessory is connected, if necessary, to the outside of the cold box through the panel 5 and a boot 8 to its actuator 10.

The chamber 1 is filled with rock wool 11.

The chamber has a trapezoid cross-section. In the figure, it is a non-rectangular, non-isosceles trapezium, as the roof is sloped at 60° to the vertical and the bottom is sloped at 45° to the vertical. It is also possible for the two angles to be identical. Otherwise, the roof and/or the bottom can be perpendicular to the panel, in which case the cross-section is a rectangular trapezium shape.

At least one wall of the chamber 1 can be perforated, for example being made from mesh or expanded metal 18. The mesh is covered with a material impermeable to a particular insulation material, with which the box is filled, for example to perlite 15, but permeable to a flushing gas. The allows the flushing gas, for example nitrogen, which circulates in the perlite 15, to circulate in the chamber in order to prevent the formation of pockets of ice or the build up of other impurities.

In FIG. 2, a distillation column 3 is arranged in a cold box consisting of eight corner panels 5, 5A having an L-shaped cross-section. Only four of the panels can be seen in the figure. The panels 5, 5A each have a chamber 1 fastened to the inner wall. Obviously, the panels of the cold box do not necessarily hold chambers. Again, the chamber is made from carbon steel or chrome and nickel alloy steel (stainless steel). It has a roof at an angle of 60° relative to a vertical plane, which is the plane of the panel 5. The bottom is sloped at 45° relative to the panel.

The chamber(s) contain(s) rock wool and the cold box is filled with perlite in use.

The column 3 is provided with pipes and can be connected to an accessory present in one of the chambers.

The chambers 1 can be fastened to the panels 5, 5A by welding or bolting. It is preferable to fasten the chamber to the panel 5A on the ground and then lift the panel 5A into position above the panel 5. It is however possible to position the chamber subsequently on its structural panel after said panel has been lifted, through an opening in the roof of the CB, or to slide it from the outside through one face of a structural panel using the catwalks of the CB.

FIG. 2 shows that the chambers are positioned before the panels of the cold box are attached to each other.

FIG. 3 shows details of the chamber 1 with its accessories such as a manual valve, automatic valve, flow meter, valve shutter or sensor, together with a pipe spool 23 connected to the accessory. The actuator 10 of the valve 9 extending outside, and the wire 21 enabling the subsequent connection of the instrumentation, can also be seen.

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.

Claims

1. A structural panel configured to form part of a cold box of a low-temperature distillation separation device, comprising at least one chamber made from carbon steel or stainless steel, the panel having a cross-section, having a roof and/or bottom sloping at an angle of between 45° and 60° relative to the panel and one open face, the open face being positioned on the inner face of the structural panel.

2. The panel according to claim 1, containing at least one accessory selected from the group consisting of a manual valve, an automatic valve, a flow meter, a valve shutter or other instrumentation means, a pipe spool connected to the accessory, and combinations thereof.

3. The panel according to claim 1, in which the chamber comprises at least one means for handling the chamber and at least one permanent or temporary support to support the at least one pipe spool and/or the at least one accessory during the transport phases and the connection to the structural panel.

4. The panel according to claim 1, in which the chamber is fastened to the panel by welding or bolting, preferably on the ground before lifting.

5. The panel according to claim 1, in which the chamber comprises at least one perforated face covered with a material that is impermeable to a particular insulation material, for example to perlite, but permeable to a flushing gas.

6. The panel according to claim 1, in which the chamber contains rock wool and/or aerogel.

7. The panel according to claim 1, wherein the cross-section is selected from the group consisting of rectangular, non-rectangular, isosceles, and trapezoidal.

8. A cold box of a low-temperature distillation separation device, comprising at least four vertical walls, at least one of which comprises the panel according to claim 1, the cold box being filled with an insulation material and containing at least one element of the device configured to operate at a low temperature or at a cryogenic temperature.

9. The cold box according to claim 8, further comprising at least one distillation column and/or at least one heat exchanger.

10. A method for assembling a cold box of a low-temperature distillation separation device, comprising at least four panels to be arranged vertically around one element configured to operate at a low temperature or at a cryogenic temperature, wherein the wall of at least one panel is provided with a chamber made from carbon steel or chrome and nickel alloy steel, having a roof and/or bottom sloping at an angle of between 45° and 60° relative to the panel and one open face, by fastening the open face to the inner face of the panel.

11. The method according to claim 9, wherein the chamber is fastened to the panel in a workshop.

12. The method according to claim 9, wherein the chamber is fastened to the panel on the installation site of the cold box.

13. The method according to claim 9, wherein the chamber is fastened to the panel on the construction site of the cold box.

14. The method according to claim 9, wherein the panels are fastened together once the chamber is fastened to the panel.

15. The method according to claim 9, wherein the cross-section is selected from the group consisting of rectangular, non-rectangular, isosceles, and trapezoidal.