U.S. patent application number 11/606940 was filed with the patent office on 2008-06-05 for apparatus for loading particulate catalytic material and loading method.
Invention is credited to Emir Zahirovic.
Application Number | 20080128045 11/606940 |
Document ID | / |
Family ID | 39474356 |
Filed Date | 2008-06-05 |
United States Patent
Application |
20080128045 |
Kind Code |
A1 |
Zahirovic; Emir |
June 5, 2008 |
Apparatus for loading particulate catalytic material and loading
method
Abstract
Apparatus for loading particulate catalytic material into
reactor tubes comprising an axial shaft capable of rotational
movement around its axis in a clockwise and counter-clockwise
direction and having attached at its lower end perpendicular to the
axis a horizontal distribution shaft, the length of which can be
varied, one end of a flexible hollow catalyst supply hose being
attached to the end of the horizontal distribution shaft extending
into the reactor space, the other end of the flexible catalyst
supply hose being available for entrance of catalyst particles
external to the reactor tube. The invention also concerns a method
of loading particulate catalytic material into a reactor tube.
Inventors: |
Zahirovic; Emir;
(Copenhagen, DK) |
Correspondence
Address: |
DICKSTEIN SHAPIRO LLP
1825 EYE STREET NW
Washington
DC
20006-5403
US
|
Family ID: |
39474356 |
Appl. No.: |
11/606940 |
Filed: |
December 1, 2006 |
Current U.S.
Class: |
141/5 |
Current CPC
Class: |
B01J 2208/00769
20130101; B01J 2208/00752 20130101; B01J 8/002 20130101; B01J 8/06
20130101 |
Class at
Publication: |
141/5 |
International
Class: |
B65B 1/04 20060101
B65B001/04 |
Claims
1. Apparatus for loading particulate catalytic material into
reactor tubes comprising an axial shaft capable of rotational
movement around its axis in a clockwise and counter-clockwise
direction and having attached at its lower end perpendicular to the
axis a horizontal distribution shaft, the length of which can be
varied, one end of a flexible hollow catalyst supply hose being
attached to the end of the horizontal distribution shaft extending
into the reactor space, the other end of the flexible catalyst
supply hose being available for entrance of catalyst particles
external to the reactor tube.
2. A loading apparatus according to claim 1, wherein the horizontal
distribution shaft comprises a plurality of horizontal shaft
sections of gradually decreasing radius extending from the axial
shaft each horizontal shaft section of smaller radius capable of
retracting into a preceding horizontal shaft sections of larger
radius.
3. A loading apparatus according to claim 1, wherein the horizontal
distribution shaft and/or comprises a plurality of horizontal shaft
sections joined end to end to form the shaft.
4. A loading apparatus according to claim 1, wherein the flexible
catalyst supply hose has circumferentially positioned ribs or
grooves.
5. A loading apparatus according to claim 1, wherein the flexible
catalyst supply hose is longitudinally cut apart from end to end to
provide a narrow slit along its entire length.
6. A loading apparatus according to claim 5, wherein the end of the
flexible-catalyst supply hose available for entrance of catalyst
particles is supported by a repositioning tube capable of a sliding
movement in the axial direction and encircling the catalyst supply
hose, the catalyst supply hose encircling a short pipe and a cover
pipe encircling and being attached to both the repositioning tube
and the short pipe, thereby holding these two pipes in place
relative, to each other, the cover pipe being capable of a sliding
movement that is coordinated with the sliding movement of
repositioning tube.
7. Loading apparatus according to claim 6, wherein the
repositioning tube partially overlaps the short pipe, the catalyst
supply hose being present in between the repositioning tube and the
short pipe.
8. Loading apparatus according to claim 4, wherein the catalyst
supply hose is enclosed by a sleeve,
9. Method of loading particulate catalytic material into a reactor
tube comprising (a) providing the lower end of an axial shaft
capable of clockwise and counter-clockwise rotation with a
horizontal distribution shaft; (b) attaching a flexible hollow
catalyst supply hose to the end of the horizontal distribution
shaft extending into the reactor space, the other end of the
flexible catalyst supply hose being available for entrance of
catalyst particles externally the reactor tube; (c) introducing
through the upper end of the catalyst supply hose particulate
catalytic material into the reactor tube; (d) distributing the
particulate catalytic material in the reactor tube by rotating the
axial shaft in a clockwise or counter-clockwise direction while
alternatively shortening the horizontal distribution shaft; (e)
thereafter shortening the axial shaft and repeating step (d) until
the reactor tube has been loaded with the required amount of
catalyst.
10. Use of the loading apparatus according to claim 1 for loading
of catalyst particles in reactor tubes for refinery processes.
Description
[0001] The invention concerns a, method and an apparatus for
loading particulate material in reactor tubes. More particularly,
the invention relates to loading of particulate, catalytic material
in reactor tubes in tubular reactors used in refinery plants.
[0002] Loading of particulate, catalytic material in tubular
reactors is conventionally performed using the sock method. With
this method, an elongated, sock-like member made of a flexible
plastic material is filled with catalyst particles and lowered into
the reactor tube with the aid of a line to which the sock is
attached. On reaching the bottom of the reactor, the line is
jerked, thus opening the sock and releasing the particles into the
reactor.
[0003] When using this method, uneven and inhomogeneous loading of
the reactor results in voids due to particle crushing by premature
sock opening or in the formation of bridges by the particles. Void
formation is undesirable because it leads to uneven temperature
distribution and variations in pressure drop in the reactor. The
voids can be partially removed by striking or:hammering the sides
of the reactor tube, causing the reactor walls to vibrate. However,
this process is labour-intensive and time-consuming.
[0004] U.S. Pat. No. 5,247,979 describes a method for filling
particulate material into a vertical tube using a line with a
damper in the form of a series of flexible, damper brushes arranged
transversely to the line. The line with damper brushes is first
lowered into the vertical tube, and then the particles are poured
into the tube. It is stated that quick, even and reproducible
filling is attained if the line is jerked a little during the
filling operation, while simultaneously being lifted up gradually
as the tube is filled.
[0005] This method, however, has several disadvantages. The falling
distance of the particles from the brushes to the bottom of the
tube is not under control, and the particles can also become wedged
in-between the brushes and the walls of the tube rendering the
apparatus immobile in the tube. The radial distance of the brushes
from the line to the walls of the tube has to correspond to the
tube diameter, which means each specific tube requires its own line
with brushes.
[0006] The above-mentioned disadvantages and others associated with
the various methods are solved by the method and apparatus of the
invention as will be apparent in the following.
SUMMARY OF THE INVENTION
[0007] It is an objective of the invention to provide a loading
method and an apparatus for filling particulate, catalytic material
in reactor tubes to ensure a uniform density profile of the loaded
catalyst bed and a flat and horizontal surface of the top of the
catalyst bed.
[0008] It is a further objective to provide a loading method, which
is highly automated and therefore reduces the possibility of human
errors and risk of reloading of reactor tubes.
[0009] It is yet an objective of the invention to provide an
apparatus whereby a uniform pressure drop and uniform flow across
the reactor bed is obtained resulting in uniform utilisation of the
catalyst.
[0010] The above objectives are achieved by the invention, which
provides a method of loading particulate catalytic material into a
reactor tube, the method comprising
[0011] (a) providing the lower end of an axial shaft capable of
clockwise and counter-clockwise rotation with a horizontal
distribution shaft;
[0012] (b) attaching a flexible hollow catalyst supply hose to the
end of the horizontal distribution shaft extending into the reactor
space, the other end of the flexible catalyst supply hose being
available for entrance of catalyst particles externally the reactor
tube;
[0013] (c) introducing through the upper end of the catalyst supply
hose particulate catalytic material into the reactor tube;
[0014] (d) distributing the particulate catalytic material in the
reactor tube by rotating the axial shaft in a clockwise or
counter-clockwise direction while alternatively shortening the
horizontal distribution shaft;
[0015] (e) thereafter shortening the axial shaft and repeating step
(d) until the reactor tube has been loaded with the required amount
of catalyst.
[0016] The invention further provides a loading apparatus being
useful in the above loading method, the apparatus comprising an
axial shaft capable of rotational movement around its axis in a
clockwise and counter-clockwise direction, and having attached at
its lower end perpendicular to the axis a horizontal distribution
shaft, the length of which can be varied, one end of a flexible
hollow catalyst supply hose being attached to the end of the
horizontal distribution shaft extending into the reactor space, the
other end of the flexible catalyst supply hose being available for
entrance of catalyst particles external to the reactor tube.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] FIG. 1 shows a loading apparatus according to the invention
in a reactor tube.
[0018] FIG. 2 shows an embodiment of the loading apparatus.
[0019] FIG. 3 shows an embodiment of the horizontal distribution
shaft.
[0020] FIG. 4 shows a transverse section through a reactor
tube.
[0021] FIG. 5 shows an embodiment of the catalyst supply hose,
[0022] FIG. 6 shows details of the attachment of the hopper to the
loading apparatus.
[0023] FIG. 7 shows an expanded view of the point of attachment of
extension pipe to short pipe.
DETAILED DESCRIPTION OF THE INVENTION
[0024] The loading apparatus according to the invention comprises
an axial shaft positioned in the reactor tube, the axial shaft
supporting at its lower end a horizontal distribution shaft
positioned perpendicularly to the axial shaft for distributing
particulate catalytic material.
[0025] The horizontal distribution shaft can be collapsed in the
axial direction to enable entrance of the loading apparatus into
the reactor.
[0026] A flexible catalyst supply hose inserted through the reactor
tube inlet is attached at one end to the horizontal distribution
shaft. The other end of the catalyst supply hose leads to a hopper
containing catalyst particles. The hopper is located outside the
reactor tube. The catalyst supply hose allows the transfer of
catalyst particles from the hopper to the horizontal distribution
shaft for distribution in the reactor tube to form a catalytic
bed.
[0027] The catalyst supply hose is a hollow flexible tube open at
both its ends and longitudinally cut apart from end to end to
provide a narrow slit along its entire length. It is bendable in
nature. The presence of the slit combined with the flexible nature
of the hose facilitates the movement and gradual removal of the
hose during and after loading. Cutting sections off the hose during
removal is avoided and the hose can thus be shortened gradually
without its destruction. The catalyst particles in the hopper enter
the catalyst supply hose and travel through it to the horizontal
distribution shaft; for distribution to form the catalytic bed.
[0028] During the distribution process the axial shaft is in a
fixed position. The horizontal distribution shaft is fixed at one
end to the lower end of the axial shaft and it can rotate around
the axial shaft with the aid of for instance gears. The opposite
end of the horizontal distribution shaft is attached to the open
end of the catalyst supply hose. The length of the horizontal
distribution shaft can be varied to provide distribution of the
catalyst particles across the required surface area of the
catalytic bed being formed. Initially prior to loading of the
catalyst, the horizontal distribution shaft is at its maximum
length corresponding to a position whereby loading of catalyst
particles initially takes place at the periphery of the reactor
tube.
[0029] The length of the horizontal distribution shaft is shortened
every time it has rotated for instance 360 degrees in a direction
perpendicular to the axis in order to distribute catalyst particles
from the periphery of the reactor tube to the center of the reactor
tube. The rotation of the horizontal distribution shaft reverses
direction after every full turn of 360 degrees in order to provide
an even distribution of the catalyst particles across the catalytic
bed. The horizontal distribution shaft alternates therefore between
clockwise and anti-clockwise rotation.
[0030] This procedure is repeated until the horizontal distribution
shaft is at its shortest length. The shortest length is obtained
when the distance between the end of the horizontal distribution
shaft attached to the catalyst supply hose and the axial shaft is
at its minimum value. The catalytic bed surface is then covered by
an even layer of catalyst particles.
[0031] The axial shaft is then moved upwards by shortening it in
order to accommodate the catalytic bed being formed. The catalyst
supply hose is also shortened. Distribution of catalyst particles
is then continued in the same manner. The horizontal distribution
shaft is initially at its shortest length when distribution starts.
Gradually the length of the horizontal distribution shaft is
increased to its maximum with alternative clockwise and
anti-clockwise rotation during distribution as described
earlier.
[0032] In order to provide smooth passage for the catalyst
particles from the hopper through the hose to the horizontal
distribution shaft the catalyst supply hose is shortened. The
narrow slit in the catalyst supply hose obtained by cutting the
hose apart longitudinally from end to end along its entire length
provides an advantage when shortening the hose. During the loading
process the catalyst supply hose is shortened by pulling the end of
the hose attached to the hopper. The flexible catalyst supply hose
thereby opens up at the longitudinal slit and can be peeled away
from the hopper while loading of the catalyst particles continues.
Destruction of the catalyst supply hose by cutting during removal
is thus avoided and the hose can be reused.
[0033] In an embodiment of the invention the catalyst supply hose
is surrounded by a sleeve of a flexible material for instance a
plastic material such as polyvinyl chloride, PVC. This prevents any
stray catalyst particles from leaving the catalyst supply hose
through the longitudinal slit.
[0034] The catalyst supply hose can be any type of hose that is
flexible in nature. Preferable is any form of rubber hose for
instance flexible rolls. Dumped down rubber hose is also suitable.
The catalyst supply hose is equipped with a slit in its axial
direction which aids in its positioning during filling of the
reactor tube with catalyst particles.
[0035] The catalyst supply hose can have ribs or grooves along its
surface or it can have a smooth surface. The presence of the ribs
or grooves provides an extra grip on the catalyst particles.
[0036] The catalyst supply hose is attached to the hopper in the
following manner: the end of the flexible catalyst supply hose
available for entrance of catalyst particles is supported by a
re-positioning tube capable of a sliding movement in the axial
direction and encircling the catalyst supply hose. The catalyst
supply hose in turn encircles a short pipe, and a cover pipe
encircles and is attached to both the repositioning tube and the
short pipe, thereby holding these two pipes in place relative to
each other. The cover pipe is capable of a sliding movement that is
coordinated with the sliding movement of repositioning tube.
[0037] In a preferred embodiment of the invention, the axial shaft
consists of a plurality of separate axial shaft sections. The axial
shaft sections can be equally sized and are assembled to form one
long axial shaft which can be inserted in a reactor tube such as a
tubular reformer. This allows for the easy assembling of the axial
shaft prior to distribution and for easy dissembling and shortening
of the axial shaft as the catalytic bed height increases.
[0038] The separate shaft sections can be assembled by for instance
screwing one section into another in any manner known in the art.
An extra pipe encircling the resulting joints can be used to
prevent dissembling of the shaft section in the event that they
become unscrewed.
[0039] In a preferred embodiment of the invention, the horizontal
distribution shaft consists of at least one horizontal shaft
section. The horizontal shaft sections can have equal lengths and
are assembled to form one long horizontal shaft attached at one end
to the bottom end of the axial shaft. The length of the horizontal
shaft can thus be adjusted to correspond to reactor tubes of
different diameters.
[0040] In another preferred embodiment of the invention, the
horizontal distribution shaft consists of two or more horizontal
shaft sections, where each section has a radius smaller than the
previous section. Each section therefore fits into or retracts into
the previous section in a telescopic manner, thereby allowing the
horizontal distribution shaft to increase or decrease in length
i.e. in radius, by gradual insertion of one section into another
using pneumatic or hydraulic means. This embodiment is advantageous
when placing the loading apparatus in the reactor tube or removing
it from the reactor tube since the horizontal shaft sections can be
extended or retracted into a more compact form that allows for
variation in radius. This also provides easy removal from the
reactor tube.
[0041] The loading apparatus can be controlled from the outside of
the reactor via a computerized system. The loading process can be
followed by mounting a video camera on the horizontal distribution
shaft.
[0042] With the method according to the invention, the risk of
crushing of catalyst particles dropped from too high a height is
eliminated.
[0043] The human factor required during loading is minimal and
continuous loading can be carried out.
[0044] A high uniform loading density and a flat and horizontal
catalyst bed surface is obtained by the method.
[0045] A uniform pressure drop and thus uniform flow through the
catalyst bed is also obtained. The result is uniform utilisation of
the catalyst and a longer catalyst life.
[0046] The catalyst loading apparatus of the invention is suitable
for loading of reactors in the chemical industry, and in particular
for loading in refinery reactors, where loading in the presence of
a gas such as nitrogen is carried out. This could for example be
loading of a hydrodesulphurisation reactor for treating naphtha.
The presence of an operator in the reactor tube is therefore not
necessary.
[0047] FIG. 1 shows a loading apparatus according to the invention
placed in a reactor tube 1 for loading of particulate catalytic
material. Axial shaft 2 is positioned in reactor tube 1 in the
tube's axial direction. Attached to the lower end 3 of the axial
shaft 2 is horizontal distribution shaft 4 for distribution of
catalyst particles. Catalyst supply hose 5 is inserted through the
reactor tube inlet 8 and is fixed at one end to the horizontal
distribution shaft 4, the other end of the hose extending through
the reactor inlet 8.
[0048] The axial shaft 2 is held in place in the reactor tube 1 by
fixation means 6. Fixation means 6 allows axial shaft 2 to move up
and down in an axial direction and prevents movement in a
horizontal direction.
[0049] The catalyst particles enter catalyst supply hose 5 at its
open end outside the reactor tube and travel through catalyst
supply hose 5 to the horizontal distribution shaft 4 for
distribution on catalyst plate 7 to form the catalytic bed.
[0050] During the distribution process the axial shaft 2 rotates
around its axis causing horizontal distribution shaft 4 to rotate
in the same direction. After a 360 degree turn the rotation
direction is reversed and the length of horizontal distribution
shaft 4 is shortened. In this way catalyst particles are
distributed on catalyst plate 7 from its periphery to its
center.
[0051] FIG. 2 shows an embodiment of the loading apparatus in which
axial shaft 2 consists of a plurality of separate axial shaft
sections 9. Axial shaft sections 9 can be equally sized if required
and are assembled to form one long axial shaft 2 which can be
inserted in a reactor. Axial shaft 2 has a final length
corresponding to the length of the reactor tube.
[0052] FIG. 3 shows an embodiment of the horizontal distribution
shaft in which horizontal distribution shaft 4 consists of at least
one horizontal shaft section 14. The horizontal shaft sections 14
can be equal in length if required and are assembled to form one
long horizontal shaft 4 attached at one end to the bottom end of
the axial shaft.
[0053] FIG. 4 shows a transverse section through reactor tube 1.
The direction of rotation of horizontal distribution shaft 4 is
shown in this case as being in a clockwise direction. Here
horizontal distribution shaft 4 is not of the telescopic type. Both
ends of horizontal shaft section 14 are shown. One end 16 is
attached to the catalyst supply hose for distribution of catalyst
particles at this end. The other end 16a extends in the reactor
space opposite the end 16. Horizontal distribution shaft 4 is
therefore able to move in a backwards and forwards direction,
thereby decreasing and increasing, respectively, its radius in the
reactor tube.
[0054] FIG. 5 shows an embodiment of the catalyst supply hose. In
this embodiment catalyst supply hose 5 has a plurality of
circumferentially positioned grooves or ribs 17. Catalyst supply
hose 5 is slit in its axial direction. This longitudinal slit 16
extends along the entire length of catalyst supply hose 5.
[0055] FIG. 6 shows an embodiment in which a hopper 18 containing
catalyst 24 is attached to catalyst supply hose 5. Hopper 18 is
provided with hopper outlet tube 25 through which catalyst
particles 24 are transferred to catalyst supply hose 5. A short
pipe 19 is fixed to hopper outlet tube 25 at joint 20 via extension
pipe 26. The short pipe 19 is positioned with its axis parallel to
the axis of catalyst supply hose 5 and it extends both above and
below extension pipe 26 at the point of attachment 27.
[0056] Flexible catalyst supply hose 5 can be opened up with the
aid of slit 16 and thereafter closed or folded around short pipe 19
both above and below extension pipe 26. Due to the flexible nature
of catalyst supply hose 5 and the presence of slit 16 catalyst
supply hose 5 opens up in the region of extension pipe 26 and is
otherwise closed or folded around short pipe 19 in its axial
direction. One end of catalyst supply hose 5 leads to the inlet of
reactor tube 1 and the opposite end of catalyst supply hose 5 above
point of attachment 27 to extension pipe 26 is held in place by
repositioning tube 21 and first cover pipe 22.
[0057] Repositioning tube 21 encircles catalyst supply hose 5,
while catalyst supply hose 5 in turn encircles short pipe 19.
Repositioning tube 21 is capable of a sliding movement, thereby
changing position in the axial direction. This sliding movement
allows repositioning tube 21 to partially or totally overlap short
pipe 19.
[0058] Cover pipe 22 encircles and is attached to both
repositioning tube 21 and short pipe 19, thereby holding these two
pipes in place relative to each other. Cover pipe 22 is also
capable of a sliding movement that is coordinated with the sliding
movement of repositioning tube 21.
[0059] A sleeve which also functions as a cover pipe (not shown)
can be present encircling catalyst supply hose 5 primarily in the
region from the point of attachment 27 of short pipe 19 to
extension pipe 26 to the inlet of reactor tube 1 or to the
horizontal distribution shaft 4. This embodiment is particularly
useful when catalyst supply hose 5 is without ribs or grooves, as
it prevents the loss of particulate catalytic material through slit
16. The sleeve can be made of for instance a plastic material such
as PVC.
[0060] A cutting device 23, for instance a razor, can be fixed in a
suitable position to facilitate cutting and thereby removal of the
sleeve after ended use. The cutting device 23 can for instance be
positioned at the point of attachment 27 of the extension pipe 26
to the short pipe 19.
[0061] FIG. 7 shows an expanded view of the point of attachment 27
of extension pipe 26 to short pipe 19 when sleeve 28 is present.
Point of attachment 27 of extension pipe 26 to short pipe 19 is
illustrated by a circular opening 29 in short pipe 19. Short pipe
19 is encircled by catalyst supply hose 5 having slit 16.
Encircling catalyst supply hose is sleeve 28.
* * * * *