Note: Descriptions are shown in the official language in which they were submitted.
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METHOD FOR PREPARING CATALYST TUBES VIA VISUAL INSPECTION,
FILING AND PRESSURE TESTING THEREOF
FIELD OF THE INVENTION
[0001] The present invention relates generally to a method and apparatus for
filling
particulate material into tubes, and more particularly, to catalyst processing
and the
loading of particulate catalyst material into reformer tubes with a uniform
density.
BACKGROUND OF THE INVENTION
[0002] Catalytic processing is required to execute certain material processing
tasks such
as chemical refinement of fluid and gaseous materials. For example, in the
process of
catalytic cracking for petroleum refinement, it is common to use a catalytic
material to
facilitate the desired cracking or other transformation. Typically, the
material to be
refined is directed through an appropriate catalytic material until a certain
level of
transformation has occurred. Because the catalytic efficiency of the system is
strongly
related to the frequency with which molecules or particles of the starting
substance
interact with the catalyst, the industry has adopted a practice of performing
such catalytic
processes in long tubes. In particular, the starting material is forced
through a set of
parallel tubes, each containing the catalyst material at a predetermined
desired density,
e.g., particles per unit volume or weight per unit volume.
[0003] The flow rate of the material through the system is equal to the sum of
the flow
rates through the multiple tubes, however, it is possible for one or more
tubes to exhibit
lower flow rates than other tubes. Lower flow rates generally are due to
clogging or
overfilling of the tubes, which can have the deleterious effect of prematurely
exhausting
or damaging the tubes with higher flow rates. Because catalytic refineries
typically are
run nonstop, it is expensive to shut the process down prematurely to service
the catalyst
tubes; maintenance on the tubes is ideally only performed once in the course
of several
years. Thus, the loading of the catalyst tubes is a critical step, and the
failure to properly
execute this step can cause the process operator to incur financial losses due
to lost
production during repair as well as increased labor costs to execute the
repairs.
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[0004] A properly prepared set of catalyst tubes will have relatively uniform
resistance to
flow from tube to tube, thus ensuring uniform flow rates, and will also have a
relatively
uniform density of catalyst from tube to tube, thus ensuring the same degree
of product
transformation for each tube. Thus, the tubes must be properly checked,
cleaned, and
filled with catalyst. Existing cleaning and filling protocols are subject to
high cost and
frequent human error due to their use of numerous personnel in time-consuming
tasks.
Although attempts have been made to solve the foregoing problems, a solution
has not
yet been devised that fully addresses the concerns without introducing further
significant
problems or costs.
OBJECTS AND SUMMARY OF THE INVENTION
[0005] It is an object of the present invention to provide a system for
ensuring tubes are
in optimal condition for automated uniform filling of particulate material,
and particularly
particulate catalyst material.
[0006] Another object is to provide an automated loading system for more
quickly and
uniformly directing the particulate material into reformer tubes.
[0007] In carrying out the invention, a reformer tube processing and filling
system is
provided for ensuring uniformity of reformer tube flow rates and reactivity.
With respect
to ensuring uniform flow rates, the subject invention provides a system for
detecting and
removing tube obstructions, as well as for verifying the flow rate for each
tube and
identifying tubes with abnormal flow rates. The verification process may be
automated,
thus removing a source of human error, and conserving labor costs.
[0008] With respect to ensuring uniform reactivity, an automated tube filling
system is
provided. The automated tube filling system provides a calibrated fill
mechanism
coordinated with a calibrated loading rope withdrawal mechanism to ensure
loading
consistency. A lack of vibrating parts ensures a low dust count, and what
little dust is
present may be removed via a built-in vacuum outlet in the loader.
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[0009] Other objects and advantages of the invention will become apparent upon
reading
the following detailed description and upon reference to the drawings, in
which:
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIGURE 1 is a simplified schematic view of a set of reformer tubes with
respect
to which the invention may be used;
[0011] FIG. 2 is cross-sectional side view of a contaminated reformer tube
undergoing
laser analysis for volume determination according to an embodiment of the
invention;
[0012] FIG. 3 is a simplified schematic view of an automated flow rate check
system for
checking tube flow rates according to an embodiment of the invention;
[0013] FIG. 4A is a flow chart illustrating an automated flow rate check
process for
execution via a computer according to an embodiment of the invention;
[0014] FIG. 4B is a flow chart illustrating a process for checking and filling
a catalyst
tube in an embodiment of the invention;
[0015] FIG. 5 is a perspective of an illustrated catalyst tube loading system
in accordance
with the invention;
[0016] FIG. 6 is a perspective of the illustrated catalyst loading system with
portions
broken away;
[0017] FIG. 7 is an enlarged perspective of the catalyst containing hopper and
dispensing
device of the illustrated loading system;
[0018] FIG. 8 is a vertical section of the catalyst hopper and dispensing
device shown in
FIG. 7 along intersection line 8-8 in Fig. 7;
[0019] FIG. 9 is an enlarged perspective of the loading rope lifting device of
the
illustrated dispensing system;
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[0020] FIG. 10 is a perspective of the lifting device shown in FIG. 9 with
portions broken
away;
[0021] FIG. 11 is an enlarged perspective of the loading rope take up spool of
the
illustrated lifting device; and
[0022] FIG. 12 is a perspective of a loading rope guide spool of the
illustrated loading
rope lifting device.
[0023] While the invention is susceptible of various modifications and
alternative
constructions, certain illustrative embodiments thereof have been shown in the
drawings
and will be described below in detail.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0024] Referring now more particularly to FIG. 1 , there is schematically
shown, a
portion of an exemplary reformer tube set 100 within which the present
invention may be
implemented to provide a uniform flow rate and processing efficiency. The
exemplary
tube set 100 includes numerous individual tubes 101, each being filled with a
catalyst
material to receive an incoming flux 103 of raw material and to provide an
outgoing flux
105 of processed material. It will be appreciated that the processed material
may include
a desired material as well as byproducts of the reformation process. Moreover,
it will be
appreciated that the illustrated tube set 100 is shown in simplified form for
the purpose of
clarification, and that an actual reformer tube set may include a greater or
lesser number
of tubes, e.g., from I to 1000 tubes, and each tube will typically be of a
much greater
length relative to its width than is illustrated. For example, typical
reformer tubes are
between 10 and 16 meters in length.
[0025] To minimize maintenance and idle costs associated with the operation of
the tube
set 100, it is desirable to ensure that each tube 101 is loaded with catalyst
(not shown in
FIG. 1) to a uniform density and that each tube 101 is of similar flow
resistance. This will
ensure that the incoming flux 103 of raw material is divided equally among the
tubes for
processing. In particular, the proportion of the incoming flux 103 of raw
material that is
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allocated to each tube 101 will depend, according to the laws of parallel
resistance, upon
the relative differences in resistance to flow between the tubes 101. If there
are no
substantial differences in flow resistance across the tube set 100 from tube
to tube, then
the incoming flux 103 of raw material will be divided equally among the tubes
101 of the
set 100.
[0026] As noted above, the parameters that affect flow rate and processing
efficiency for
each tube are flow resistance, tube volume, and catalyst density. Although
these
parameters are not entirely dependent, each will be addressed separately
herein for the
sake of clarity. Those of ordinary skill in the art will appreciate the degree
to which and
manner in which each of these parameters may affect the others.
[0027] Pursuant to one aspect of the invention, in order to ensure uniform
flow resistance
across the tubes 101 of the tube set 100, each tube 101 is checked for
contaminating
deposits and is cleaned if necessary. In an embodiment of the invention, empty
tubes are
first inspected for contamination. In a particular embodiment of the
invention, the
inspection mechanism is a video camera mounted on an extended flexible member
such
as a rod, for lowering into the tube of interest. In an alternative embodiment
of the
invention, the inspection mechanism comprises a laser sensor to measure the
total amount
of foreign matter in the tube.
[0028] Referring now more particularly to FIG. 2, a cross-sectional side view
of a
contaminated tube 200 is shown. Tube 200 is also referred to as reformer tube
200 in the
following. In the illustrated example, the tube wall 201 is contaminated by
multiple
deposits 203, 205 of byproduct materials. In the case of petroleum refinement,
the
deposits 203, 205 may be tar-like deposits, sulfur or other mineral deposits,
or other
byproduct or contaminant substances.
[0029] In the illustrated embodiment of the invention, a laser sensor system
207 is used to
analyze the content of the tube. The laser system 207 may be a scanning or
sweeping
laser system, or other system configured to analyze substantially all of the
interior of the
tube 200. The laser sensor system 207 in an embodiment of the invention
determines the
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volume of the tube 200 that is displaced by the deposits 203, 205. Although
very small
deposits need not be removed, it is desirable to clean the tube 200 if the
amount of
contaminant displacement exceeds a certain threshold, e.g., 5% of the nominal
volume of
the tube 200. Those of skill in the art will be aware of the means available
to remove
contaminant deposits such as those illustrated in FIG. 2, and these means need
not be
further discussed herein.
[0030] In order to ensure uniform processing, each tube 200 is checked for
flow
resistance after the removal of any deposits to the extent such is required.
Referring now
to FIG. 3, each tube 200 is connected to a flow checker system 300 to check
the flow
resistance. The flow checker system 300 comprises a computer 301, an airflow
source
303 connected to the computer 301 so as to be computer-actuated, and a flow
and/or
pressure sensor 305, e.g., a manometer, connected to the computer 301 so as to
be
computer readable.
[0031] In operation, the airflow source 303 is mechanically connected to the
tube 200
(with the deposits 203, 205 having been removed). At this point, the computer
301
executes a program, e.g., a body of computer-executable instructions stored on
a
computer-readable medium such as a hard drive, to verify the flow resistance
of the tube
200.
[0032] The flow checker process executed by the computer 301 is illustrated
via process
400 in the flow chart of FIG. 4 A. At stage 401 of the process 400, the
computer 301
actuates the airflow source 303, e.g., via a digital relay, to force air
through the tube 200.
As the air passes through the tube 200, the manometer or other flow and/or
pressure
sensor 305 is caused to measure the flow resistance of the tube 200 at stage
403. For
example, the computer 301 may read a digital or analog output of the sensor
305 at this
stage. The measurement of the flow resistance will be based upon a difference
in pressure
or flow caused by any obstruction. For example, a tube 200 with a partially
obstructed
output, and hence higher flow resistance, will exhibit both decreased flow and
increased
pressure relative to a similar tube without any obstruction. The computer 301
optionally
repeats the measurements at either the same or different input conditions at
stage 405.
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[0033] At stage 405, the computer 301 logs the measured values in a chart,
e.g., an
EXCEL chart or other chart. After a desired number of tubes have been
analyzed, e.g.,
one hundred tubes, the computer 301 identifies in stage 407 via a chart or
listing any
tubes that fall outside of a predetermined range or variance relative to the
other tubes
analyzed. For example, the computer 301 may list as abnormal any tube that
exhibits a
flow resistance that is more than 5% different from the average flow
resistance of the set
of tubes.
[0034] The overall process of filling, incorporating the procedure of FIG. 4A,
but also
incorporating additional processes, will now be discussed with reference to
FIG. 4B. The
illustrated combined process 450 starts at a time when the catalyst tubes are
empty, either
because they are new tubes or because they have been recently emptied and
cleaned. At
stage 451, the tube is video inspected to determine whether closer scanning of
the tube is
to be performed. Any manner of video inspection may be used, but in an
embodiment of
the invention, a video camera is lowered on an arm or wire into the tube
interior, and
transmits video of the surface under inspection to a video display, such as a
small monitor
or laptop computer outside the tube.
[0035] If such inspection reveals that scanning necessary, e.g., because there
are
ambiguous video inspection results that may or may not indicate contamination,
then the
process proceeds to stage 453. At stage 453, the tube interior is closely
scanned to
identify dirt or contamination deposits that may need to be removed. Although
any
suitable scanning means may be used, in an embodiment of the invention, such
scanning
is executed via a rotating laser scanner lowered into the tube interior. The
laser scanner
measures the inside radius of the tube, to detect any deposits therein.
[0036] If the scanning of stage 453 reveals depots to be removed, the process
flows stage
455. At stage 455, the tube inside wall is cleaned. Although any suitable
process of
cleaning may be used, in one embodiment, the cleaning is executed via a
brushing device
inserted into the tube, for accomplishing mechanical, e.g., abrasive, removal
of any
identified deposits. The cleaning may focus only on identified deposits or may
be
executed uniformly within the tube.
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[0037] After cleaning is accomplished at stage 455, or in the event that
either of stages
451 or 453 resulted in a decision that no scanning or cleaning, respectively,
was needed,
the process flows to stage 457. At stage 457, the pressure drop through the
tube is
measured. Although it will be appreciated that there are several ways to
measure such a
pressure drop, the pressure drop is measured in one embodiment of the
invention via the
apparatus described with reference to FIG. 3.
[0038] After the pressure drop is initially measured, the tube is filled with
catalysts and
the pressure drop again measured in stage 459. The loading of stage 459 may be
executed
via the loading mechanism described below or via another mechanism. Finally,
at a stage
not shown in Figure 4B, the average pressure drop across a plurality of such
filled tubes
for parallel use as in FIG. 1 is calculated, and it is verified that the
reading for the present
tube is within a predetermined variance of that average. In an embodiment of
the
invention, a variance of +2% is used to indicate a maximum acceptable
deviation from
the average. If the pressure reading for the tube is within the accepted
level, then the
process terminates, and otherwise, any necessary corrective action such as
emptying,
rechecking, and refilling, are executed as necessary.
[0039] Referring now more particularly to FIGS. 5-6 of the drawings, there is
shown an
illustrative automated catalyst loading system 500 in accordance with the
invention that is
adapted for automatically filling the cleaned and checked tubes, such as tube
200 in stage
459 of process 450, with particulate catalyst of uniform density and with
minimum
damage to catalyst particles and tube structures. The illustrated automated
loading system
500 includes a fork fill tube 501 having a vertically disposed connecting tube
portion 502
mounted on and communicating with an upper end of a reformer tube 200 to be
filled and
a fill tube portion 504 supported by and communicating at an angle with a side
of the
vertical connecting tube portion 502. The vertical connecting tube portion 502
and the
reformer tube 200 have respective lips 505,506 which define a coupling joint
for
facilitating releasable securement of the tubes 200,501 together.
[0040] For directing particulate catalyst into the forked fill tube 501 and in
turn into the
reformer tube 200 for continuous uniform filling, a selectively operable motor
driven
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catalyst dispenser 510 is provided. The catalyst dispenser 510 includes an
open top
hopper 511 for holding a supply of catalyst 512 as shown in Fig. 8 which in
this case has
a support frame or structure 513 at one end to facilitate mounting of the
hopper 511 in a
processing facility. The bottom of the hopper 511 is defined by an endless
conveyor belt
514 trained about a pair of horizontally spaced drums or pulleys 515, 516 such
that an
upper leg of the endless belt 514 extends along a bottom opening 518 of the
hopper 511.
The drums or pulleys 515,516 in this instance are rotatably supported by
underlining
frame members 520 of the hopper 511. For moving the conveyor belt 514 to
transfer
catalyst 512 from the hopper 511, a drive motor 521 is operably coupled to the
pulley or
drum 515. Operation of the motor 521 will thereby direct catalyst from the
hopper to a
downstream end of the conveyor belt 514 (i.e., the right hand end as viewed in
FIGS. 7-8)
for direction into a discharge shoot 522 defined by a semi-circular cover 524
mounted at
one end of the hopper 511, and in turn its an upper end of the fill tube
portion 504 and the
reformer tube 200.
[0041] For controlling the flow of catalyst 512 introduced into the reformer
tube 200, a
loading rope or line 530 is suspended within the reformer tube 200 for lifting
movement
as the catalyst fills the tube. The loading rope 530 may be of a known type
having
damper members 531 in the form of a plurality of radially extending transverse
bristles
disposed at spaced intervals along the rope. The brush bristles of the damper
members
531 preferably are flexible springs having a transverse radial dimension
slightly less than
the radius of the reformer tube 200 for reducing the speed of the falling
catalyst particles
so that breakage is avoided and the catalyst more uniformly fills the tube
without
undesirable voids.
[0042] In keeping with a further aspect of the loading system, for further
facilitating the
efficient and uniform introduction of catalyst 512 into the reformer tube 200,
an
automatic loading rope take-up device 540 is provided for withdrawing the
loading rope
530 from the reformer tube 200 at a predetermined rate. To this end, in the
illustrated
embodiment, the take-up device 540 includes a motor driven take-up spool 541
to which
an upper end of the loading rope 530 is secured such that upon selective
rotation of the
take-up spool 541, the rope 530 is wound about the take-up spool 541 as it is
raised from
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the reformer tube 200 at a predetermined calibrated rate as determined by the
rotational
speed of the take-up spool 541.
[0043] The take-up spool 541 in this case is rotatably mounted in a frame 542
which can
be appropriately mounted in the processing facility, such as by hanging from
the ceiling
by an upstanding hook 544a mounted on the upper most end of the frame 542. The
illustrated take- up spool 541 comprises an inner cylindrical hub 544 to which
laterally
spaced circular side plates 545 are fixed, and a plurality of
circumferentially spaced rods
546 are interposed between the side plates 545 in outward radial relation to
the inner hub
544 which define an interrupted, non circular, winding surface of the drum.
[0044] For rotating the take-up spool 541, the central hub 544 has a drive
shaft 548 which
is driven by a drive motor 549 mounted on the frame 542 via a drive belt or
chain 550.
With an upper end of the loading rope 530 secured to the take-up spool 541,
rotation of
the take-up spool 541 by the drive motor 549 will cause the take-up rope to be
wound
upon the take-up drum and raised from the reformer tube at a predetermined
rate
governed by the operating speed of the motor 549. The plurality of
circumferentially
spaced rods 546 that define the effective non-circular winding surface of the
take-up
spool 541 cause the loading rope 530 to be raised with irregular movement for
preventing
build-up of catalyst on the damper members 531, while also facilitating
positioning of the
damping members 531 in flattened positions on the take-up spool 541 during
such rotary
take-up movement.
[0045] To further facilitate continuous loading of catalyst into the tube
without
undesirable build-up of catalyst on the loading rope 530, the loading rope 530
is trained
about a rotatable eccentric spool 560 disposed adjacent the take-up spool 541
which is
effected for successively causing the rope to swing or move up and down as it
is drawn
onto the take-up spool 541. The eccentric spool 560 in this case comprises a
central
rotatable drive shaft 561, a pair of laterally disposed circular side plates
562 mounted on
the drive shaft central hub 563 as shown in Fig. 12, and a pair of
diametrically opposed
rods 564 disposed between the side plates 562 outwardly of the drive hub 563.
Rotation
of the eccentric drive spool 560 by a drive belt or chain 566 coupled to the
output shaft
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551 of the drive motor 549 will cause the eccentric spool 560 to rotate
simultaneously as
the take-up spool 541 rotates to lift the loading rope 530 from the reformer
tube 200. The
diametrically opposed rods 564 of the rotating eccentric spool 560
successively engage
and swing the loading rope 530 in up and down fashion to dislodge and prevent
accumulation of catalyst on the damper members 531 as the rope 530 is raised
from the
reformer tube 200.
[0046] In accordance with a further important aspect of the catalyst loading
system 500, a
control is provided for controlling operation of the drive motors 521 and 549
such that
loading rope 530 is raised from the reformer tube in calibrated synchronized
relation to
the operating speed of the feed conveyor belt 514 for ensuring continuous,
uninterrupted
loading of catalyst with enhanced uniformity. To this end, operation of the
motors
521,549 may be driven under the control of a computer such as the computer
301, or such
other computer 570 dedicated exclusively to the drive motors 521,549. Within
the
computer 301 and/or 570, computer-readable code stored on a computer-readable
medium such as a disc or drive is read and executed by the computer processor.
Such
code acts to operate the drive motors 521 and 549 in a synchronized manner via
suitable
output drivers such as a digital to analog converter or transducer. The motor
synchronization may be based either on empirical data regarding flow rates and
settling
and the like, or via feedback that adjusts the relative speeds of the motors
based on the
actual instantaneous fill level within the tube. In the latter case, detection
of fill level may
be via optical measurement or other suitable measurement technique.
[0047] As will be understood by a person skilled in the art, the loading rope
530 should
be raised at a rate such that the lower-most damping member 531 of the loading
rope 530
is raised from the reformer tube 200 at a speed such that it stays just above
the level of
catalyst deposit in the tube. More importantly, by means of the computer
control, the rate
at which the loading rope 530 is lifted from the reformer tube 200 is
synchronized with
the speed of the loading conveyor belt 514 for the particular loading
operation. In each
case, continuous loading of catalyst into the reformer tube 200 permits
quicker, more
uniform filling of the tubes. Indeed, the possibility of human error
associated with
conventional practices of filling reformer tubes is eliminated since a large
number of
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tubes may be loaded in exactly the same manner and speed, resulting in
uniformity of the
filled tubes 200 and reduced pressure drop variations therein. The catalyst
loading system
500 of the present invention has been found to enable up to 20% faster loading
as
compared to manual techniques with more uniform consistency of the catalyst
loaded into
the tubes.
[0048] It has been found that such improved loading efficiency and performance
is
enabled by virtue of the ability to automatically and continuously fill the
reformer tubes
200 in a predetermined controlled manner without interruption. To facilitate
such
continuous automated loading of the tubes, it will be understood that the
hopper 511
should be maintained at least partially filled with catalyst by personnel or
by an automatic
filler (not shown).
[0049] It will be further appreciated that since the continuous automated
filling system
500 fills the tubes 200 with enhanced particle uniformity, there is no need to
tap the tubes
to prevent voids in the loaded catalyst typical of prior art procedures. As a
result, the
automated loading system 500 eliminates the need for vibrational elements and
thus
reduces the production of catalyst dust. In order to remove any small amounts
of dust
from the catalyst that may occur during transfer from the conveyor belt 514
into the
discharge shoot 522, a vacuum device 580 may be mounted in communication with
a
vacuum outlet 581 formed by a screened wall in the discharge shoot cover duct
524.
[0050] It will be appreciated that a new and useful system for reformer tube
filling and
processing has been described herein by way of example. However, it is
contemplated
that other implementations of the disclosure may differ in detail from the
foregoing
examples. All references to the disclosure or examples thereof are intended to
reference
the particular example being discussed at that point and are not intended to
imply any
limitation as to the scope of the disclosure more generally. All language of
distinction
and disparagement with respect to certain features is intended to indicate a
lack of
preference for those features, but not to exclude such from the scope of the
disclosure
entirely unless otherwise indicated.
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[0051] Recitation of ranges of values herein are merely intended to serve as a
shorthand
method of referring individually to each separate value falling within the
range, unless
otherwise indicated herein, and each separate value is incorporated into the
specification
as if it were individually recited herein. All methods described herein can be
performed
in any suitable order unless otherwise indicated herein or otherwise clearly
contradicted
by context.
