U.S. patent application number 13/257000 was filed with the patent office on 2012-01-05 for feeding apparatus and method for a pyrolytic reactor.
This patent application is currently assigned to T.D.E. Recovery Technologies Ltd.. Invention is credited to Alexander P. Bronshtein, David Shalom Jakobowitch, Menachem L. Skop, Moshe Weiss.
Application Number | 20120000761 13/257000 |
Document ID | / |
Family ID | 42739249 |
Filed Date | 2012-01-05 |
United States Patent
Application |
20120000761 |
Kind Code |
A1 |
Bronshtein; Alexander P. ;
et al. |
January 5, 2012 |
FEEDING APPARATUS AND METHOD FOR A PYROLYTIC REACTOR
Abstract
A Feeding apparatus for a pyrolytic reactor, comprising a
rotatable inclined drum, a motor for rotating the drum, a hopper by
which aggregatable feedstock pieces introduced to the interior of
said drum, and a feed tube extending from the drum to a pyrolytic
reactor. The rotation of the drum applies forces of sufficient
magnitude and varying direction to an aggregated mass of feedstock
pieces that constituent feedstock pieces are separated from said
aggregated mass and are discharged from the drum via the feed tube
to the pyrolytic reactor.
Inventors: |
Bronshtein; Alexander P.;
(Beer Sheva, IL) ; Skop; Menachem L.; (Beer Sheva,
IL) ; Weiss; Moshe; (Tel Aviv, IL) ;
Jakobowitch; David Shalom; (Bnei Brak, IL) |
Assignee: |
T.D.E. Recovery Technologies
Ltd.
Beer Sheva
IL
|
Family ID: |
42739249 |
Appl. No.: |
13/257000 |
Filed: |
March 16, 2010 |
PCT Filed: |
March 16, 2010 |
PCT NO: |
PCT/IL10/00218 |
371 Date: |
September 16, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61160842 |
Mar 17, 2009 |
|
|
|
Current U.S.
Class: |
201/7 ;
202/262 |
Current CPC
Class: |
Y02P 20/143 20151101;
F27B 7/00 20130101; F27D 3/16 20130101; C10J 3/66 20130101; B65G
11/206 20130101; F23G 5/20 20130101; C10J 2300/094 20130101; F27B
7/362 20130101; F27B 7/42 20130101; C10J 2300/0956 20130101; C10B
53/07 20130101; C10B 1/10 20130101; F27B 7/20 20130101; Y02E 20/12
20130101; C10J 2300/0946 20130101; F23G 5/0276 20130101; C10J
2300/0973 20130101; C10B 51/00 20130101; C10B 49/04 20130101; F27B
7/10 20130101 |
Class at
Publication: |
201/7 ;
202/262 |
International
Class: |
C10B 35/00 20060101
C10B035/00 |
Claims
1. Apparatus for continuously feeding aggregatable feedstock pieces
without aggregation to a pyrolytic reactor, comprising: a) a
rotatable inclined drum; b) a plurality of longitudinally
extending, circumferentially spaced plates which radially extend
from the inner surface of said drum, at least one of said plurality
of plates longitudinally extending from an inlet end of said drum
which is located above an outlet end of said drum; c) stationary
inlet port means through which aggregatable feedstock pieces are
introduced to the inlet end of said drum; d) motor means for
rotating said drum; e) hopper means in communication with said
inlet port means, said hopper means comprising an inclined surface
for gravitationally directing the feedstock pieces via said inlet
port means to the interior of said drum and directly to said at
least one plate longitudinally extending from the inlet end of said
drum; f) stationary outlet port means for discharging the feedstock
pieces from the outlet end of said drum; and g) feed tube means
extending from said outlet port means to a pyrolytic reactor,
wherein rotation of said drum applies forces of sufficient
magnitude and varying direction to an aggregated mass of feedstock
pieces supported by one of said plates such that said mass falls
onto a second drum bottom region after being upwardly rotated for a
sufficiently large angular distance from a first drum bottom region
to an ending angle, causing constituent feedstock pieces to become
separated from said mass as a result of the impact of the fall,
wherein substantially all feedstock pieces discharged from said
drum via said feed tube means to the pyrolytic reactor are
non-aggregated pieces.
2. (canceled)
3. The feeding apparatus according to claim 1, wherein more than
one layer of aggregated masses is supportable and upwardly
rotatable by a plate.
4. (canceled)
5. The feeding apparatus according to claim 1, which is
sufficiently sealed to prevent the escape to the environment
therefrom, during a feeding mode, of gaseous products of pyrolysis
discharged from the reactor via the feed tube means.
6. The feeding apparatus according to claim 5, further comprising
means for preventing any gaseous products of pyrolysis from
escaping from the drum or the hopper means to the environment
during a loading mode.
7. The feeding apparatus according to claim 6, wherein the escaping
preventing means comprises means for purging the drum and hopper
means from the gaseous products.
8. The feeding apparatus according to claim 7, wherein the purging
means comprises a gas supply device for supplying a purging gas not
reactable with the feedstock pieces or with the gaseous
products.
9. The feeding apparatus according to claim 8, wherein the purging
gas is introducible into the hopper means and is deliverable
together with the gaseous products to the reactor.
10. The feeding apparatus according to claim 8, wherein the purging
gas is carbon dioxide.
11. The feeding apparatus according to claim 8, wherein the purging
gas comprises purified flue gases.
12. The feeding apparatus according to claim 7, wherein the
escaping preventing means further comprises a knife valve
operatively connected to the feed tube means, for isolating the
reactor from the drum of the feeding apparatus during the loading
mode.
13. The feeding apparatus according to claim 1, wherein the hopper
means comprises cover elements through which feedstock pieces are
introducible during the loading mode.
14. The feeding apparatus according to claim 13, wherein the cover
elements are automatically openable and closable.
15. The feeding apparatus according to claim 14, further comprising
a controller for commanding initiation of a purging operation prior
to initiation of a loading operation.
16. The feeding apparatus according to claim 15, further comprising
a gas analyzer in data communication with the controller, for
transmitting a signal when the hopper means and drum has been
purged, the controller operable, following transmission of said
signal, to: a) command termination of the purging operation; b)
command actuation of a knife valve operatively connected to the
feed tube means, for isolating the reactor from the drum of the
feeding apparatus; c) command to open the cover elements; and d)
command operation of a conveying system whereby feedstock pieces
are deposited into the hopper means.
17. The feeding apparatus according to claim 15, wherein the
controller is in communication with a limit switch for transmitting
a signal when the height of feedstock pieces within the hopper
means falls below a predetermined value, the controller operable to
initiate a loading operation following transmission of said
signal.
18. The feeding apparatus according to claim 1, wherein the drum is
frusto-conical such that the diameter of the drum is smaller at its
outlet end than at its inlet end.
19. Method for feeding aggregatable feedstock pieces to a pyrolytic
reactor, comprising the steps of: a) loading a plurality of
feedstock pieces containing organic matter to an inclined drum
comprising a plurality of longitudinally extending,
circumferentially spaced plates which radially extend from the
inner surface of said drum, at least one of said plurality of
plates longitudinally extending from an inlet end of said drum; b)
rotating said drum, whereby any aggregated mass of loaded feedstock
pieces is conveyed gravitationally to an outlet end of said drum
while continuously decreasing in size as a result of cyclical
upwardly rotating and falling motion, wherein for each cycle said
mass is supported by one of said plates such that it is upwardly
rotated within said drum for a sufficiently large angular distance
from a first drum bottom region to an ending angle whereat said
mass falls, to cause one or more feedstock pieces to become
separated from said mass as a result of the impact of a fall onto a
second drum bottom region; and c) discharging substantially only
non-aggregated feedstock pieces from said drum via feed tube means
to a pyrolytic reactor.
20. The feeding apparatus according to claim 7, wherein the
escaping preventing means during the loading mode comprises: a)
means for purging the drum and hopper means from the gaseous
products prior to loading the hopper means; b) a gas supply device
for supplying a purging gas not reactable with the feedstock pieces
or with the gaseous products; c) a knife valve operatively
connected to the feed tube means, for isolating the pyrolytic
reactor from the drum of the feeding apparatus during the loading
mode; d) a plurality of pivotable cover elements for releasably
covering the hopper means, sealing elements being provided on the
underside of each of said cover elements; and e) controller means
for automatically opening and closing said plurality of cover
elements.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to feeding apparatus. More
particularly, the present invention relates to an apparatus and
method for feeding tire pieces, or any other aggregatable feedstock
pieces, to a pyrolytic reactor.
BACKGROUND OF THE INVENTION
[0002] At present, the recovery of discarded tires remains a
serious problem, despite certain achievements in this field. Some
discarded tires are utilized in civil engineering and in road
construction, as well as in the manufacturing of different goods.
Nevertheless about 30% of discarded tires, and in some countries,
up to 80%, are still disposed in stockpiles. A large number of
tires are located outside of the stockpiles, and pollute the
surrounding area. On the other hand the non-utilized discarded
tires may present a valuable raw material being a source of
chemical energy due to the organic and carbonized components
contained in this material.
[0003] Most of the known methods for converting the rubber
containing materials of tires into useful product gases are based
on pyrolysis. A pyrolysis process generally operates at
temperatures of about 500.degree. C. in a low oxygen atmosphere and
results in producing hydrogen-hydrocarbon gas, a liquid hydrocarbon
product, and a solid material. The solid material comprises a
carbonized part and the steel cord of the tire.
[0004] Prior art feeding apparatus has dealt with different methods
for feeding small tire pieces, i.e. less than 200 mm, to a
pyrolytic reactor. For example, U.S. Pat. No. 5,225,044 discloses
gravity fed comminuted pieces. U.S. Pat. No. 6,221,329 discloses a
rotatable feed cylinder having a first end coupled to the feed
chamber and a second end coupled to the pyrolysis section. The feed
cylinder has a continuous screw-like flight extending radially
inward from an inner wall of the feed cylinder, for directing tire
pieces from the first end to the second end of the feed cylinder as
the feed cylinder rotates.
[0005] Some drawbacks are associated with these prior art methods.
Firstly, high pre-processing costs are involved in shredding tires
to small pieces. Secondly, the prior art methods are not suitable
for feeding larger sized tire pieces as the tire pieces become
aggregated, impeding movement of the tire pieces being fed as well
as forming a large mass which would reduce exposure to heat carrier
gases during the pyrolytic process.
[0006] It is an object of the present invention to provide a
feeding apparatus which is suitable for feeding relatively large
sized, non-aggregated tire pieces to a pyrolytic reactor.
[0007] It is another object of the present invention to provide a
feeding apparatus which ensures that product gases will not escape
from the pyrolytic reactor when tire pieces are fed thereto so as
not to pollute the environment.
SUMMARY OF THE INVENTION
[0008] The present invention is directed to feeding apparatus for a
pyrolytic reactor, comprising a rotatable inclined drum; motor
means for rotating said drum; hopper means by which aggregatable
feedstock pieces are introduced to the interior of said drum; and
feed tube means extending from said drum to a pyrolytic reactor,
wherein rotation of said drum applies forces of sufficient
magnitude and varying direction to an aggregated mass of feedstock
pieces that constituent feedstock pieces are separated from said
aggregated mass and are discharged from said drum via said feed
tube means to the pyrolytic reactor.
[0009] Preferably, a plurality of longitudinally extending,
circumferentially spaced plates radially extend from the inner
surface of the drum, an aggregated mass of feedstock pieces
supported by one of said plates being upwardly rotated thereby for
a sufficiently large angular distance from a drum bottom region to
an ending angle whereat said mass falls, causing one or more
feedstock pieces to become separated from said mass as a result of
the impact of the fall. More than one layer of aggregated masses is
supportable and upwardly rotatable by a plate.
[0010] In one aspect, substantially all feedstock pieces discharged
from the drum are non-aggregated pieces.
[0011] The feeding apparatus is sufficiently sealed to prevent the
passage therefrom, during a feeding mode, of gaseous and vaporous
products of pyrolysis (hereinafter "gaseous products" for brevity)
flowing through the feed tube means.
[0012] In one aspect, the feeding apparatus further comprises means
for preventing any gaseous products of pyrolysis from escaping from
the drum or hopper means to the environment during a loading mode.
As referred to herein, the term "loading mode" refers to operation
of adding feedstock pieces to the hopper means for the first time,
or for any other additional times.
[0013] In one aspect, the escaping preventing means comprises means
for purging the drum and hopper means from the gaseous products.
The purging means comprises a gas supply device for supplying a
purging gas not reactable with the feedstock pieces or with the
gaseous products. The purging gas, e.g. carbon dioxide or purified
flue gases, may be introduced into the hopper means and delivered
together with the gaseous products to the reactor.
[0014] In one aspect, the escaping preventing means comprises a
knife valve operatively connected to the feed tube means, for
isolating the reactor from the drum during the loading mode.
[0015] In one aspect, the hopper means comprises cover elements
through which feedstock pieces are introducible during the loading
mode, and which may be automatically openable and closable.
[0016] In one aspect, the feeding apparatus further comprises a
controller for commanding initiation of a purging operation prior
to initiation of a loading operation, and possibly a gas analyzer
in data communication with the controller, for transmitting a
signal when the hopper means and drum has been purged, the
controller operable, following transmission of said signal, to
command termination of the purging operation; command actuation of
a knife valve operatively connected to the feed tube means, for
isolating the reactor from the drum of the feeding apparatus;
command to open the cover elements; and command operation of a
conveying system whereby feedstock pieces are deposited into the
hopper means.
[0017] In one aspect, the controller is in communication with a
limit switch for transmitting a signal when the height of feedstock
pieces within the hopper means falls below a predetermined value,
the controller operable to initiate a loading operation following
transmission of said signal.
[0018] In one aspect, the drum is frusto-conical such that the
diameter of the drum is smaller at its outlet end than at its inlet
end.
[0019] The present invention is also directed to a method for
feeding aggregatable feedstock pieces a pyrolytic reactor,
comprising the steps of loading a plurality of aggregatable
feedstock pieces to a drum; rotating said drum, whereby any
aggregated mass of loaded feedstock pieces is upwardly rotated
within said drum for a sufficiently large angular distance from a
drum bottom region to an ending angle whereat said mass falls, to
cause one or more feedstock pieces to become separated from said
mass as a result of the impact of the fall; and discharging
substantially only non-aggregated feedstock pieces from said drum
via feed tube means to a pyrolytic reactor.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] In the drawings:
[0021] FIG. 1 is a perspective view of feeding apparatus and a
pyrolytic reactor according to one embodiment of the present
invention;
[0022] FIG. 2 is a side view of the feeding apparatus of FIG. 1,
showing cover elements of a hopper in an opened position;
[0023] FIG. 3 is an enlarged perspective view of Detail A of FIG.
2, showing the drive means for rotating the drum;
[0024] FIG. 4 is a longitudinal cross sectional view of the feeding
apparatus, cut about plane A-A of FIG. 2;
[0025] FIG. 5 is a cross sectional view of the drum cut at plane
B-B of FIG. 2, showing a plurality of radially extending
plates;
[0026] FIG. 6 is a cross sectional view of the drum cut at plane
B-B of FIG. 2, showing a plurality of aggregated masses of
feedstock pieces that are being rotated about the inner surface of
the drum;
[0027] FIG. 7 is a side view of a conveying system by which
feedstock pieces are introduced to a hopper;
[0028] FIG. 8 is a block diagram of a control system associated
with the feeding apparatus; and
[0029] FIG. 9 is a side view of the feeding apparatus according to
another embodiment of the invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0030] The novel feeding apparatus of the present invention is
suitable for feeding relatively large sized tire pieces, or any
other aggregatable (hereinafter "feedstock pieces"), to a pyrolytic
reactor without aggregation. The feeding apparatus is operable in
two modes. The primary mode is the feeding mode during which
feedstock pieces are transferred from the feeding apparatus to a
pyrolytic reactor. The second mode is a loading mode during which
feedstock pieces are loaded into the feeding apparatus without
interfering with the operation of the pyrolytic reactor. The
feedstock pieces that are loaded are generally relatively large
sized pieces cut by conventional equipment, so that the high
pre-processing costs involved in shredding feedstock pieces to
smaller pieces are avoided. In both modes, gaseous products are
prevented from escaping the reactor and feeding apparatus and from
polluting the atmosphere.
The Feeding Mode
[0031] FIG. 1 illustrates a feeding apparatus according to one
embodiment of the present invention, and is generally designated by
numeral 10. Feedstock pieces are loaded in hopper 15, whereupon
they are introduced into drum 6. The feedstock pieces discharged
from drum 6 are introduced via feed tube 2 to pyrolytic reactor 40.
The gaseous products are discharged from the reactor through exit
pipe 50, and the solid residue is discharged through exit tube 56
to transportable bin 57.
[0032] Pyrolytic reactor 40 may be any pyrolytic reactor well known
to those skilled in the art for pyrolyzing the feedstock pieces and
generating gaseous, liquid and solid products. Alternatively,
pyrolytic reactor 40 may be the reactor described in the copending
international patent application bearing Attorney's Docket No.
26656/WO/10 and entitled "A PYROLYTIC REACTOR", comprising an inner
drum circumferential wall formed with a plurality of apertures
through which heat carrier gases flow and are directable to a
selected region of the inner drum interior for an improved rate of
heat transfer, the contents of which are incorporated herein by
reference.
[0033] With respect to prior art feeding apparatus, relatively
large feedstock pieces, and particularly tire pieces, having a
size, e.g. thickness, greater than 20 mm and generally on the order
of 200 mm or greater, tend to aggregate together to form a large
mass, e.g. the greatest dimension of which being on the order of
0.5 m or more. Without being bound to any theory, the cut surface
of freshly cut tire pieces, or of any other aggregatable feedstock
in random directions due to the irregular shape of the feedstock
pieces and has a characteristic adhesiveness that promotes
aggregation with other feedstock pieces. An aggregated mass of
surprisingly high structural strength is formed when a plurality of
freshly cut feedstock pieces become aggregated together. When the
feedstock pieces are tire pieces, the pieces also become entangled
due to the presence of steel cords which extend in many different
directions and may pierce a tire piece. This aggregated mass tends
to clog feed tube 2, reducing the rate by which feedstock pieces
are fed to reactor 40, and therefore the reactor output. Even if it
were successfully introduced into reactor 40, an aggregated mass
would have limited movement within the reactor, reduce the exposure
of the feedstock piece to heat carrier gases during the pyrolytic
process, and would therefore significantly reduce the pyrolytic
performance of the reactor.
[0034] Feeding apparatus 10 of the present invention is adapted to
ensure that the feedstock pieces delivered via feed tube 2 to
pyrolytic reactor 40 will be prevented to aggregate together to
form such a large mass of feedstock pieces, or if already
aggregated together within hopper 15 or within the interior of drum
6, will be forced to separate from adjacent feedstock pieces, as
will be described hereinafter.
[0035] FIG. 2 illustrates a side view of feeding apparatus 10.
Apparatus 10 comprises a rotatable drum 6 to which feedstock pieces
are introduced via stationary inlet port 3 and from which feedstock
pieces are discharged to the feed tube via stationary outlet port
8. Drum 6 may be frusto-conical, tapering from a relatively large
diameter at inlet end 21 to a relatively small diameter at outlet
end 22. Drum 6 may be slightly inclined at an angle, e.g. ranging
from 0.5-10 degrees, such that the inlet end 21 is above outlet end
22. Inlet port 3 is in communication with hopper 15.
[0036] With reference also to FIG. 3, rings 4 and 7 are fixedly
attached to, or integral with, the outer surface of drum 6 adjacent
to its inlet and outlet ends, respectively. Each of rings 4 and 7
is supported by a pair of rollers 16 rotatably mounted to a base,
e.g. a crossbeam 33 connected to a support beam 39. A gear wheel 5
is also fixedly attached to, e.g. by welding, to the outer surface
of drum 6 so that gear wheel 5, rings 4 and 7, and drum 6 are
concentric. Teeth 17 of gear wheel 5 are in kinematic relation with
the output gear 18 of a motor 14, causing drum 6 to rotate, e.g. at
a predetermined or controlled speed, which may be synchronized with
the speed of pyrolytic reactor 40. A typical speed of drum ranges
from 0.2-2 rpm.
[0037] As shown in FIGS. 4 and 5, the frusto-conical drum 6 is
provided with a plurality, e.g. four, of longitudinally extending,
circumferentially spaced plates 28, for supporting the aggregated
masses of feedstock pieces during their upward rotation within the
interior of the drum. Plates 28 may have a rectangular cross
section as shown, or may be configured with any other desired cross
section that is suitable for supporting an aggregated mass of
feedstock pieces.
[0038] Each plate 28 radially extends from the inner surface 26 of
drum 6 for a small fraction of the diameter of the drum. The
applicants have surprisingly found that the use of relatively
radially-short plates will dramatically increase the angular
distance to which an aggregated mass can be upwardly rotated.
[0039] For example, aggregated masses having a thickness of 150-200
mm may be upwardly rotated by a drum without plates for an angular
displacement of 30 degrees. However, by providing four
circumferentially spaced plates 28 having a radial length L of 30
mm for an ending drum diameter D of 1 m, the radial fraction L/D
that each plate occupies being only 3%, the angular displacement
was increased to 100 degrees.
[0040] The following description is related to the separation of
relatively large sized tire pieces from an aggregated mass. The
manner of separation may be different when the feedstock pieces are
of other types.
[0041] As shown in FIG. 6, the rotation of drum 6, for example in
direction R, facilitates the separation of an aggregated mass of
feedstock pieces into individual pieces. For purposes of clarity,
three aggregated masses 35, 36 and 37 of feedstock pieces are shown
to be disposed within the interior 25 of drum 6, after having been
introduced therein by means of the hopper. It will be appreciated,
however, that many more aggregated masses may be found at given
moment within drum 6, and the separation method described
hereinbelow will simultaneously take place in many different zones
within interior 25.
[0042] Since drum 6 is slightly downwardly inclined, aggregated
masses 35-37 will be conveyed gravitationally to the outlet end of
drum 6. In addition to being conveyed gravitationally, aggregated
masses 35-37, or the constituent feedstock pieces 32, are also
conveyed by means of the rotation of drum 6. Mass 35 is shown to be
located in the vicinity of drum bottom B. Mass 36 is shown to be
upwardly rotated with respect to bottom B while being in contact
with inner surface 26 and supported by a corresponding plate 28.
Mass 37 is shown to be falling towards bottom B, after having been
upwardly rotated throughout an angular distance D from the drum
bottom B to an ending angle E corresponding to the height above
bottom B at which an aggregated mass separates from inner surface
26. The value of angular distance D depends upon the speed of drum
6, the coefficient of friction of the feedstock pieces, and the
ratio of the inlet diameter to the outlet diameter of drum 6.
Angular distance D is advantageously increased by virtue of the
gradual decrease of the drum diameter from the inlet end to the
outlet end.
[0043] As a result of the impact resulting from the fall of mass 37
onto drum surface 26 or onto other feedstock pieces, some feedstock
pieces, e.g. pieces 32A-B, become separated from the aggregated
mass. The aggregated masses located at a downstream portion of the
drum 6 continue the cycle of upwardly rotating and falling, while
continuously decreasing in size due to the separation of
constituent feedstock pieces, until they are displaced to the
outlet end. Those separated feedstock pieces that have fallen to
the drum bottom will continue to be upwardly rotated and be thereby
advanced to outlet end 22, and from there to outlet port 8 (FIG.
4). Surprisingly, all constituent feedstock pieces of the formerly
aggregated masses are non-aggregated pieces at the outlet end, and
therefore can be discharged into feed tube 2 (FIG. 1) without
concern of feed tube clogging, which would result in poor reactor
output and performance.
[0044] A rear region 41 of an aggregated mass 35 located in the
vicinity of drum bottom B will generally be contacted and supported
by a forward planar side surface 29 of plate 28, all of which
indicated with respect to the rotational direction R of drum 6. The
aggregated masses are generally, but not necessarily, characterized
by a triangular formation that has relatively thin forward and rear
regions and a relatively thick central region terminating at apex
47. Although rear region 41 of the triangular mass is in abutting
relation with plate 28 and apex 47 generally protrudes from plate
28, the high structural strength of the aggregated mass retains the
constituent feedstock pieces as a single entity and resists
separation of the feedstock pieces while they are being upwardly
rotated. The impact upon falling, however, generates forces that
cause a plurality of feedstock pieces 32 to become separated from
the aggregated mass.
[0045] A plurality of aggregated mass layers may be caused to be
upwardly rotated. In the illustrated example, the apex of mass 37
may fall on the central region of mass 35 and then change its
orientation due to the temporary instability of mass 37 upon
establishing falling contact with mass 35. Feedstock pieces 32
become separated from mass 37 upon impact with mass 35 and as a
result of a change in orientation. A reshaped aggregated mass 37'
is thereby formed and settles on forward region 46 of mass 35.
[0046] Although mass 37' is not in abutting contact with a plate
28, the former will be caused to be upwardly rotated since it is
stably supported by mass 35, which in turn will be supported by
plate 28A during the subsequent rotation of drum 6. When additional
masses fall on mass 35 or 37', a portion of the additional masses,
whether forwardly or rearwardly from plate 28A, may apply a force
onto a corresponding portion of an outwardly disposed aggregated
mass portion, i.e. in a direction towards the circumferential wall
of drum 6, which urges the outwardly disposed portion towards the
inner surface of drum 6. The force applied by a first layer onto a
second layer at different angles may retain the feedstock pieces in
contact with inner surface 26 of drum 6, or in contact with
adjacent feedstock pieces, thereby increasing the angular
displacement of an aggregated mass within the drum, the depth of
fall within the drum interior, and therefore the rate of
separation.
[0047] The plates 28 need not be of the same longitudinal length.
For example as shown in FIG. 4, plate 28A may longitudinally extend
throughout drum 6A, from inlet end 21 to outlet end 22, while
plates 28B and 28C extend only from a central region of drum GA,
e.g. in the vicinity of gear wheel 5, to outlet end 22. The
provision of plate 28A at inlet end 21 allows feedstock pieces
introduced to drum 6A directly from hopper 15 to become engaged
with plate 28A and to begin the cyclical process of upward rotation
and falling. Drum 6 may protrude within the interior of outlet port
8, so that plate 28A may also extend to the end of the drum to
convey feedstock pieces to the outlet port.
[0048] The rate of feedstock piece separation from an aggregated
mass will generally increase when fewer feedstock pieces have been
introduced to the drum; however, the economical viability of the
feeding apparatus will be impaired. Controller 81 (FIG. 8) may
control the operation of motor 14 and therefore the speed of the
drum, in order to optimize both the rate of feedstock piece
separation from an aggregated mass and the rate of feeding
feedstock pieces to the pyrolytic reactor.
[0049] Stationary outlet port 8 has a tubular periphery 26 defining
a hollow interior 31, and is provided with an opening 27 at its
inlet, to allow the separated feedstock pieces to be introduced
into interior 31. An aperture 34 in which is fitted vertical tube
part 10 is formed at the bottom of periphery 26.
[0050] The feedstock pieces introduced to outlet port 8 are
gravitationally delivered to the feed tube, which may comprise
vertical tube part 10 and elbow part 11 mounted to a support beam
or to any other support element suitable for fixating the elbow
part. Elbow part 11 has a greater diameter than vertical tube part
10 and is combined therewith by means of sealing means 12 and
packing material 16, to provide a single curving passageway through
which the feedstock pieces are delivered from outlet port 8 to the
pyrolytic reactor without being subjected to excessive stress.
Alternatively, elbow 11 may be an integral portion of feed tube 2
(FIG. 1).
[0051] Since feed tube 2 is in communication with the interior of
reactor 40, as shown in FIG. 1, some of the gaseous products,
including hydrocarbons, hydrogen sulfide, and possibly sulfur and
oxygenated organic substances, may flow via feed tube 2 to drum 6
and hopper 15. To prevent the escape of the gaseous products from
feeding apparatus 10 to the surrounding environment during normal
feeding and pyrolyzing operations, pivotable cover elements 72 of
hopper 15 are provided on the underside thereof with sealing
elements 79 (FIG. 2), only a portion of the latter being
schematically illustrated. Additionally, sealing means 51 and 52
associated with stationary inlet port 3 and outlet port 8 (FIG. 4),
respectively, which is provided with packing material, interfaces
with the rotating drum 6 to prevent escape of the gaseous
products.
[0052] As further shown in FIG. 4, a knife valve 9 may be
operatively connected to vertical part 10, to isolate the gaseous
products within the reactor interior during the loading mode. When
knife valve 9 is actuated, the planar valve element and the
surrounding sealing element sufficiently occludes vertical part 10
so that the gaseous products will be prevented from flowing from
the reactor interior to the interior of drum 6, flowing to hopper
15, and damaging the environment.
[0053] Outlet port 8 has a hatch 37, which can be opened in order
to access the interior of drum 6 during periods of emergency.
The Loading Mode
[0054] As shown in FIG. 7, feedstock pieces 32 may be conveyed to
hopper 15 by a conventional conveyor belt system 60, whereby a
plurality of feedstock pieces are received in each hook-shaped
receiving element 62 attached to an inclined endless belt 64, are
conveyed to an uppermost portion of the belt that is supported by
roller 67, and are deposited into hopper 15 while the receiving
elements are rotated to the underside of belt 64. Inclined surface
69 of hopper 15 helps to gravitationally direct the deposited
feedstock pieces to drum 6A. It will be appreciated that any other
conveyor system well known to those skilled in the art may likewise
be employed.
[0055] As shown in FIG. 2, hopper 15 is provided with a plurality
of cover elements 72 that can be pivoted upwardly when feedstock
pieces are to be deposited into the interior of the hopper and that
can be pivoted downwardly when the conveying process is to be
terminated.
[0056] As shown in FIG. 8, the feeding apparatus may be provided
with a controller 81, in order to facilitate the automatic loading
of feedstock pieces into the hopper. Controller 81 may be in
communication with a limit switch 83 positioned in the hopper.
Limit switch 83 is adapted to transmit a signal to controller 81
when the height of feedstock pieces within the hopper falls below a
predetermined value, whereupon the controller initiates a loading
operation.
[0057] The applicants have found that an effective pyrolytic
performance can be achieved by operating the pyrolytic reactor
continuously, while the drum of the feeding apparatus is also
operated continuously, with the exception of an approximate three
minute interval per hour during which feedstock pieces are loaded
into the hopper.
[0058] Since some of the gaseous products may flow from the reactor
interior to the drum interior of the feeding apparatus as described
hereinabove, the gaseous products are liable to escape from the
feeding apparatus to the environment when hopper cover elements 72
are opened prior to a loading operation. During the three minute
loading operation interval, or any suitable interval determined
necessary for the efficient operation of the feeding apparatus and
of the pyrolytic reactor, controller 81 commands to initiate a
purging operation whereby feeding apparatus is purged from the
gaseous products and delivered to the reactor interior. A gas
analyzer 86, or alternatively a plurality of sensors, in data
communication with controller 81 determines when a sufficient
amount of the gaseous products has been removed, whereupon knife
valve 9 is actuated and occludes vertical part 10 (FIG. 4) in order
to load hopper 15 with feedstock pieces while preventing the
passage of gaseous products to hopper 15.
[0059] Prior to the purging operation, controller 81 commands the
purging gas supply device 76, e.g. a blower or a control valve, to
become activated. With reference also to FIG. 4, purging gas G is
introduced during a period of one to two minutes to hopper 15 via
inlet chamber 66 of the hopper, or through any other selected inlet
in communication with the feeding apparatus. Purging gas G may be a
gas such as carbon dioxide that does not react with the feedstock
pieces, or alternatively, may be purified flue gases, e.g. gases
exhausted from a combustion process wherein one or more of its
reactants are the gaseous products of pyrolysis. The pressure and
flowrate of purging gas G are sufficiently high to urge the gaseous
products located within the drum interior or within the hopper
interior to flow towards the reactor interior. The controller also
commands knife valve 9 to occlude the tube part with which it is
operatively connected while drum motor 14 rotates very slowly, e.g.
0.1 rpm, so that the feedstock pieces remaining in the drum will be
deposited on the planar element of knife valve 9.
[0060] Purging gas supply device 76 is then commanded to be
deactivated and conveying system 60 is then commanded to deposit
feedstock pieces into the hopper. Slightly after commencement of
the conveying operation, controller 81 commands cover elements 72
to open and purging gas supply device 76 to become deactivated.
When the purging gas is carbon dioxide which has a density greater
than air, the carbon dioxide remains in the hopper until the
feedstock pieces are loaded.
[0061] Upon conclusion of the loading operation, the steps are
reversed, namely conveyor system 60 is deactivated, cover elements
72 are closed, knife valve 9 is set to an opened position, drum
motor 14 is activated to its normal operating speed.
[0062] In one embodiment, the drum motor may be operated
continuously, at a normal or a near normal speed. To prevent excess
accumulation of feedstock pieces, two independently operable knife
valves 9A and 9B may be operatively connected to vertical part 10
of the feed tube, as shown in FIG. 9. When the purging operation is
terminated, hopper cover elements are opened and the gas supply
pump is deactivated. The controller then commands lower knife valve
9B to occlude vertical tube part 10. After a predetermined time
during which a predetermined amount of feedstock pieces have
accumulated on lower knife valve 9B, the controller commands upper
knife valve 9A to occlude tube segment 10 and lower knife valve 9B
to be opened. The feedstock pieces then fall into the reactor,
after which knife valve 9B is set to an occluded position and knife
valve 9A is set to an opened position. Upon conclusion of the
loading operation, knife valves 9A and 9B are set to an opened
position, to allow the feedstock pieces to be freely delivered to
the pyrolytic reactor. Thus doses of feedstock pieces may be fed to
the reactor by means of the two independently operable knife
valves.
[0063] While some embodiments of the invention have been described
by way of illustration, it will be apparent that the invention can
be carried out with many modifications, variations and adaptations,
and with the use of numerous equivalents or alternative solutions
that are within the scope of persons skilled in the art, without
departing from the spirit of the invention or exceeding the scope
of the claims.
* * * * *