U.S. patent application number 10/545493 was filed with the patent office on 2006-07-06 for distillation apparatus and method of transporting the same.
This patent application is currently assigned to Air Products and Chemicals, Inc. Invention is credited to Stephen John Gibbon.
Application Number | 20060144684 10/545493 |
Document ID | / |
Family ID | 9953256 |
Filed Date | 2006-07-06 |
United States Patent
Application |
20060144684 |
Kind Code |
A1 |
Gibbon; Stephen John |
July 6, 2006 |
Distillation apparatus and method of transporting the same
Abstract
A distillation column 2, suitable for the cryogenic distillation
of air or the thermal distillation of hydrocarbon gas, is supported
within an insulation structure 4 from interior corners of said
structure. This apparatus and method of support avoid placing
significant stresses on the column during transportation. The
apparatus is particularly suitable for columns having a diameter of
at least 3.5 m (11 ft).
Inventors: |
Gibbon; Stephen John;
(Banstead, GB) |
Correspondence
Address: |
CAESAR, RIVISE, BERNSTEIN,;COHEN & POKOTILOW, LTD.
11TH FLOOR, SEVEN PENN CENTER
1635 MARKET STREET
PHILADELPHIA
PA
19103-2212
US
|
Assignee: |
Air Products and Chemicals,
Inc
7201 Hamilton Boulevard
Allentown
PA
18195
|
Family ID: |
9953256 |
Appl. No.: |
10/545493 |
Filed: |
February 12, 2004 |
PCT Filed: |
February 12, 2004 |
PCT NO: |
PCT/GB04/00542 |
371 Date: |
February 1, 2006 |
Current U.S.
Class: |
202/133 |
Current CPC
Class: |
F25J 2290/42 20130101;
F25J 3/04945 20130101; F25J 3/0489 20130101 |
Class at
Publication: |
202/133 |
International
Class: |
C10B 1/06 20060101
C10B001/06 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 18, 2003 |
GB |
0303750.4 |
Claims
1. Apparatus comprising a distillation column and an insulation
structure, characterised in that said column is supported within
said structure from interior corners of said structure.
2. Apparatus as claimed in claim 1 wherein the column has a
diameter of at least 3.5 m (11 ft).
3. Apparatus as claimed in claim 1 wherein the column has a
diameter of about 5 m (16 ft) or about 6 m (20 ft).
4. Apparatus as claimed in claim 1 wherein the column is supported
using radial supports provided between each corner of the
insulation structure and the outer wall of the column.
5. Apparatus as claimed in claim 4 wherein the column is supported
using at least two sets of radial supports provided along the
length of the column.
6. Apparatus as claimed in claim 4 wherein the column comprises an
internal stiffening structure to disperse local stresses imposed on
the wall of the column by the radial supports.
7. Apparatus as claimed in claim 6 wherein the internal stiffening
structure remains in the column during distillation.
8. Apparatus as claimed in claim 6 wherein the thickness of the
wall of the column is less than the thickness required to support
the column both during transit and when erected on site without an
internal stiffening structure.
9. Apparatus as claimed in claim 1 wherein the column is a
cryogenic air distillation column.
10. (canceled)
11. A method of transporting apparatus comprising a column and an
insulation structure, said method comprising supporting said column
within said structure from interior corners of said structure and
transporting said apparatus.
12. A method as claimed in claim 11 wherein the column has a
diameter of at least 3.5 m (11 ft).
13. (canceled)
14. A method as claimed in claim 11, wherein the column has a
diameter of about 5 m (16 ft) or about 6 m (20 ft).
15. A method as claimed in claim 11, wherein the column is
supported using radial supports provided between each corner of the
insulation structure and the outer wall of the column.
16. A method as claimed in claim 11, wherein the column is
supported using at least two sets of radial supports provided along
the length of the column.
17. A method as claimed in claim 11, wherein the column comprises
an internal stiffening structure to disperse local stresses imposed
on the wall of the column by the radial supports.
18. A method as claimed in claim 11, wherein the internal
stiffening structure remains in the column during distillation.
19. A method as claimed in claim 11, wherein the thickness of the
wall of the column is less than the thickness required to support
the column both during transit and when erected on site without an
internal stiffening structure.
20. A method as claimed in claim 11, wherein the column is a
cryogenic air distillation column.
Description
[0001] The present invention relates to a distillation column in
combination with an insulation structure or container. The
invention is primarily concerned with large distillation columns,
for example columns having a diameter of about 3.5 m (about 11 ft)
or more, and is of particular application to cryogenic distillation
columns. However, the invention could also be employed with other
separation columns such as hydrocarbon gas separation columns.
[0002] There are many examples of apparatus comprising a
distillation column and an insulation structure or container. For
example, U.S. Pat. No. B-6,360,545 discloses apparatus comprising a
cryogenic unit, e.g. an air separation unit, and an insulating
containment enclosure. The apparatus is designed to contain
cryogenic liquid leaking from the cryogenic unit and is
particularly suitable for off shore applications.
[0003] At present, the maximum production of oxygen from an air
separation plant is about 3500 metric tons/day (about 3860 short
tons/day). Over the next few years, it is believed that there will
be a need for plants that are capable of producing oxygen at a rate
that is well over 3500 metric tons/day (3860 short tons/day). One
way to satisfy this demand would be to provide a plurality of
conventional oxygen plants in parallel. However, another way would
be to use a column having a larger diameter, e.g. a diameter of
about 6 m (about 20 ft).
[0004] The maximum size of a cryogenic air distillation column is
limited by a number of factors. One such factor is the ability of
the final column to be transported by road.
[0005] Conventionally, smaller cryogenic air distillation columns,
e.g. those having a diameter of 3 m (10 ft) or less, are usually
transported within the insulation structure or "cold box". The
combination is usually transported horizontally by road on the back
of a lorry having a low load platform. Such columns are usually
transported on specially designed "transport saddle" structures
with the insulation structure in place around the column. One
advantage of such an arrangement is that the column is delivered to
site with the insulation structure, together with the necessary
pipe work within the cold box, already in place. The column and
insulation structure combination is simply hoisted into position on
site. An insulation material, usually perlite, is added to the
cavity between the column and the inner wall of the insulation
structure and the pipe work within the cold box is then connected
to the pipe work of the remaining parts of the plant.
[0006] One advantage of shipping a conventional distillation column
within the insulation structure is that the quality of the
construction can be controlled to a greater degree. Cryogenic air
separation units may be required almost anywhere. Most locations
have airborne contaminants such as dirt and/or grease and, in some
locations, these contaminants will include corrosive contaminants,
for example, salt (if the location is near the sea) or sand (if the
location is in a desert). Transportation of a fully assembled
column within the insulation structure means that the internal
components of the column are not exposed to any airborne
contaminants on site.
[0007] Transport saddles have to be supported by shipping beams
which form part of the insulation structure. This is a disadvantage
of conventional support means as the saddles and beams take up
space within the insulation structure and make it difficult to run
piping to one face (e.g. the lower face during transportation) of
the cold box. A further disadvantage is that the saddles impose
significant local stresses in the wall of the distillation column
to the extent that it is often necessary to thicken up the
distillation column wall in the vicinity of the saddles.
[0008] Large columns, e.g. ones that have a diameter of about 3.5 m
(about 11 ft) or more, cannot be transported by road in combination
with an insulation structure using conventional support means. A
column having a diameter of about 6 m (about 20 ft) is about the
largest diameter column that can be transported by road fully
assembled but, at present, it cannot transported within its
insulation structure. This is because the saddles and shipping
beams provided within the cold box would make the column and cold
box combination too tall, even when provided on its side, to travel
under all but the highest bridges. Therefore, the conventional
proposal is to transport large columns to site, either as an
assembled column (without the cold box) or as column parts. The
column would then be erected on site and the insulation structure
erected around the column. However, this is far less convenient
and, where the column is transported in sections, there is a risk
that the internal components of the large column are contaminated
and/or damaged by airborne contaminants. There is a need,
therefore, for a new and convenient method of transporting large
columns to site such that this risk is reduced.
[0009] U.S. Pat. No. B-6,202,305 discloses a method of constructing
air distillation apparatus comprising an interior column provided
within an exterior framework. The method has particular application
to apparatus comprising a column that is so large, e.g. having a
height as much as 60 metres, that it has usually to be transported
separately from the framework and constructed on site. The method
comprises constructing modules in which a section of the column is
pulled into and joined to a corresponding section of the framework
and in which the modules are joined together on site. In the
exemplified embodiment, screw jacks are used to support and
position a column section within a corresponding framework section
in a module. The screw jacks are placed between a belt provided on
and around the column section and a cross member of a face of the
framework section.
[0010] U.S. Pat. No. A-4,116,150 discloses a container for the
storage or transportation of cryogenic liquids. The container has
corner supports that react against tension loads on the walls of
the container when the container is loaded with cryogenic
liquid.
[0011] DE-A-19737520 discloses a cryogenic air distillation
installation comprising at least one rectifying column disposed
within an insulating chamber. The rectifying column is secured in
the insulating chamber by means of rope shaped members provided
between the exterior of the column and the interior of the
insulating chamber. In the exemplified embodiment, the insulating
chamber is cylindrical and the rope shaped members extend radially
from a ring provided on and around the exterior of the column to
the interior wall of the insulating chamber.
[0012] DE-A-19804438 discloses a steel construction for shaft and
cavern construction. The steel construction is particularly
suitable for use in nuclear research and with magnet technology.
The steel construction consists of a cylindrical body surrounded by
a number of coaxial polygonal support rings. Each support ring is
formed of a number of segments and is spaced apart from a
neighbouring support ring by integral support lugs. Support ribs
are provided between the innermost support ring adjacent the
corners of the polygonal ring and the cylindrical body.
[0013] According to a first aspect of the present invention, there
is provided apparatus comprising a distillation column and an
insulation structure, characterised in that said column is
supported within said structure from interior corners of said
structure. The column may be a hydrocarbon distillation column but,
in preferred embodiments, the column is a cryogenic air
distillation column.
[0014] One advantage of supporting a column within an insulation
structure from interior corners of the structure is that, for an
insulation structure of given dimensions, larger columns may be
transported by road than would be possible if conventional
(non-removable) saddles and shipping beams are employed to support
the column. In this way, assembly of large columns can take place
in a controlled environment thereby reducing the risk of
contamination of the internal components. The present invention is,
therefore, suitable for use with large columns having a diameter of
at least 3.5 m (11 ft) and is particularly suitable for use with
columns having a diameter of about 5 m (about 16 ft) or about 6 m
(about 20 ft).
[0015] The column of the present invention is usually supported
using sets of radial supports provided between each corner of the
insulation structure and the outer wall of the column. The radial
supports are typically made from material having low thermal
conductivity giving low heat leak. Suitable materials include
stainless steel.
[0016] Radial supports provided between each corner of the
insulation structure and the column have an added advantage over
saddles as they are suitable for use as seismic or wind supports
once the column is erected on site whereas the saddles are only
suitable for vertical or near vertical loading when the column is
being transported. In addition, more space within the insulation
structure is available making it possible to run piping along the
lower face of the insulating structure.
[0017] The number of sets of radial supports depends on the overall
length of the column. Typically, two sets of radial supports are
used although more could be used to reducing the bending stresses
in the column.
[0018] The use of radial supports imposes significant local
stresses in the wall of the distillation column. The contact points
between the supports and the column wall may be stiffened by
increasing the thickness of the wall in the area of these points.
However, in preferred embodiments, internal stiffening structures
or "bracing" may be used. The bracing may be made from piping or
from structural sections having, for example, channelled, angled,
T- or I-cross sections. Such bracing structures would usually be
left inside the column when the column is in use as it would be
undesirable to open the column on site to remove the bracing
structure. Therefore, the bracing structure is preferably made from
a material that is suitable for exposure to the conditions inside
the column during use. For a cryogenic distillation column, the
bracing is typically made from the same material as the column.
This material is usually selected from aluminium (or an aluminium
alloy), stainless steel (various grades), 9% nickel steel or any
other material suitable for cryogenic temperatures.
[0019] The use of internal bracing means that the thickness of the
column wall is usually less than the thickness required to support
the column both during transit and when erected on site, e.g.
hoisted from the horizontal position to the vertical position,
without an internal stiffening structure. The thickness of the
column wall is a function of operating pressure, design code,
diameter of material of construction. These factors change from one
plant to the next as is readily appreciated by the skilled
person.
[0020] According to a second aspect of the present invention, there
is provided a method of transporting apparatus comprising a column
and an insulation structure, said method comprising supporting said
column within said structure from interior corners of said
structure and transporting said apparatus. The apparatus may have
any or all of the features described above.
[0021] The following is a description, by way of example only and
with reference to the accompanying drawings, of presently preferred
embodiments of the invention. In the drawings:
[0022] FIG. 1 is a representation of a radial cross-section of a
conventional distillation column having a diameter of no more than
3 m (10 ft) in combination with an insulation structure;
[0023] FIG. 2 is a representation of an axial partial cross-section
of the column and insulation structure combination depicted in FIG.
1;
[0024] FIG. 3 is a representation of a radial cross-section of a
distillation column in combination with an insulation structure
according to the present invention;
[0025] FIG. 4 is a representation of an axial partial cross-section
of the column and insulation structure combination depicted in FIG.
3;
[0026] FIG. 5 is a representation of a radial cross-section of a
column of the present invention comprising a first internal
stiffening structure;
[0027] FIG. 6 is a representation of a radial cross-section of a
column of the present invention comprising a second internal
stiffening structure; and
[0028] FIG. 7 is a representation of a radial cross-section of a
column of the present invention comprising a third internal
stiffening structure.
[0029] Referring to FIGS. 1 and 2, a conventional cryogenic air
distillation column 2 having a diameter of no more than 3 m (10 ft)
is located within an insulation structure or "cold box" 4. The
column 2 is supported on a transport saddles 6 and shipping beams 8
which take up space and make it difficult to run piping (not shown)
to the lower surface of the cold box 4. In FIG. 2, the column 2 is
supported by two saddles 6. Each saddle 6 is about 20% of the total
length of the column 2 away from the nearest end of the column 2
respectively in order to reduce the bending stressing within the
column 2. The saddles 6 impose significant local stresses in the
distillation column wall such that it is often necessary to
increase the thickness of the column wall in contact with the
saddles.
[0030] Referring to FIGS. 3 and 4, a cryogenic distillation column
32 having a diameter of at least 3.5 m (11 ft), for example about 5
m (16 ft) or about 6 m (20 ft), is located within a cold box 34.
The column 32 is supported by radial supports 36 provided between
corner members 38 of the frame of the cold box 34. Using radial
supports in this way allows a column having a
larger-than-conventional diameter to be transported in a given size
of cold box. In addition, space is available between the lower
surface of the cold box 34 and the column 32 in which piping (not
shown) is located.
[0031] Radial supports will typically impose significant local
stresses in the distillation column such that it will be necessary
to either increase the thickness of the column wall locally and/or
to use an internal stiffening structure or "bracing" to react to
the loads. FIGS. 5 to 7 depict three arrangements of suitable
internal stiffening structures. In each arrangement, the bracing is
usually fabricated from tubular members or structural sections
(e.g. channels, angles and T- or I-beams). The column 52 in FIG. 5
is braced with internal radial supports 54. The column 62 in FIG. 6
is braced with internal supports 64 provided in a square
arrangement. The column 72 in FIG. 7 is braced with internal
supports 74 arranged about the interior surface of the column
wall.
[0032] Whilst the present invention has been discussed with
particular reference to the production of oxygen from an air
separation process, it is to be understood that the invention can
be applied to the production of any gas using cryogenic separation
processes or indeed to the distillation of a gaseous hydrocarbon
mixture.
[0033] Throughout the specification, the term "means" in the
context of means for carrying out a function, is intended to refer
to at least one device adapted and/or constructed to carry out that
function.
[0034] It will be appreciated that the invention is not restricted
to the details described above with reference to the preferred
embodiments but that numerous modifications and variations can be
made without departing from the spirit or scope of the invention as
defined by the following claims.
* * * * *