Note: Descriptions are shown in the official language in which they were submitted.
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This invention relates to a method and apparatus for separating
tar from tar sand or shale.
Canadian Patent No. 1,095,845, which issued to the present
inventor on February 17, 1981, discloses the basic concept underlying the
present invention, namely the use of striker blades or arms to separate
the tar from sand or shale particles (hereinafter referred to as the par-
ticulate carrier). Basically, the apparatus and method disclosed by such
patent are designed for a one shot separation. A single vessel containing
a set of striker arms or blades effects the basic separation.
Obviously, there exists a need for a continuous separation
method which can be used on a large scale, and for an apparatus for carry-
ing out such a method. While a series of apparatuses of the type described
in the patent could be strung together side-by-side, the result would be a
somewhdt bulky system which would effect no better separation than the
basic patented apparatus.
The object of the present invention is to meet, at least
partially, the need mentioned above by providing a simple, yet efficient
method and apparatus for separating a relatively high percentage of tar
from a particulate carrier.
Accordingly, the present invention relates to a method for
separating tar from a particulate tar-containing carrier comprising the
steps of:
(a) conveying the carrier in a layer along a path of travel;
(b) adding water to said carrier layer during travel along
said path of travel to soften said carrier;
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(c) adding steam under pressure to said carrier layer to
facilitate tar separation;
(d) striking the carrier layer to separate tar therefrom;
(e) removing the tar separated from the carrier layer;
(f) adding additional steam under pressure to said carrier
layer;
(g) striking the carrier layer to separate additional tar; and
(h) removing the additional tar separated from the carrier
layer.
The invention also relates to an apparatus for separating tar
from a particulate tar-containing carrier comprising:
(a) conveyor means for conveying a layer of said carrier along
a path of travel;
(b) first pipe means for adding water to said carrier layer
during travel along said path of travel;
(c) second pipe means for injecting steam into said carrier
layer during travel along said path of travel;
(d) a plurality of first striker blades extending across sub-
stantially the entire path of travel for strik1ng said carrier layer to
separate tar therefrom;
(e) first scraper means for removing the tar separated from
the carrier layer;
(f) third pipe means for injecting steam under pressure into
said carrier layer;
(g) a plurality of second striker blades extending across sub-
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stantially the entire path of travel for striking said carrier layer to
separate tar therefrom; and
(h) second scraper means for removing the tar separated from
the carrier layer.
In the preferred embodiment of the apparatus, the particulate
material is carried along a straight line of travel by an elongated hori-
zontal conveyor, with a vertical conveyor at each side thereof. The
vertical conveyors travel in the same direction as the horizontal conveyor
and define a trough with such conveyor. All three conveyors travel at the
same speed (preferably 100-200 feet per minute) to reduce friction between
the particulate carrier and the sides of the trough. The striker blades
rotate in a direction parallel to the path of travel to strike the carrier
as it flows against the blades. The blades are covered with a sticky sub-
stance which has an affinity to the tar. Tar separated from the carrier
is removed from the striker blades by scraper arms, which feed the tar to
conveyors for further processing or refining. Following initial tar sep-
aration by the striker blades, tar froth in aqueous suspension is removed
from the top of the particulate carrier. The froth is filtered to recover
the tar, and the filtered water can be reused in the separation apparatus.
The invention will now be described in greater detail with
reference to the accompanying drawings, which illustrate a preferred em-
bodiment of the apparatus of the present invention, and wherein:
~igure 1 is a schematic, longitudinal sectional view of a
separation apparatus in accordance with the present invention,
Figure 2 is a schematic plan view of all but the front or in-
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let and discharge ends of the apparatus of Figure 1;
Figure 3 is a schematic, longitudinal sectional view on a
larger scale than Figure 1 of portions of the apparatus of Figures 1 and
2 near the front or inlet and discharge ends thereof;
Figure 4 is a schematic plan view on a larger scale than Figure
2 of the inlet and discharge ends of the apparatus of Figures l to 3; and
Figure 5 is a schematic perspective view of striker blades and
a scraper used in the apparatus of Figures 1 to 4.
The apparatus of the present invention is used to separate tar
from a particulate carrier, namely tar sand or tar shale. The mined tar
sand is washed and then fed directly to the apparatus of the present in-
vention. The tar shale is washed, crushed and softened with heat and
pressure before being fed to the apparatus described hereinafter. The
softening of the shale can be effected by means of heavy perforated rollers
(not shown) which press against the shale on a conveyor, high pressure
(200-300 psi) steam being fed to the rollers for acting on the shale.
With reference to Figures 1 and 2, the particulate, oil-bearing
carrier 1 is fed by a horizontal conveyor 2 to a lower conveyor 3 for pro-
cessing. The conveyor 2 passes around rollers 4. A cover 5 is provided
above the conveyor 2 for controlling the thickness of layer 6 of particu-
late carrier on the conveyor 3. The conveyor 3, which passes around
rollers 7, is horizontal along substantially the entire length thereof,
sloping upwardly at discharge end 8. The conveyor 3 is bordered on each
side by vertical conveyors 9 and 10, which pass around rollers 11 and 12,
respectively. The conveyors 3, 9, and 10 define a trough for the particu-
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late carrier, the entire trough moving in the same direction as the partic-
ulate material. The use of sides which move with the horizontal conveyor 3
eliminates friction between the sides and the particulate carrier layer 6.
Hot water is fed through pipe 13 into the carrier 1 at ;nlet
end 14 of the conveyor 3 to place the carrier in suspension. It has been
found that the addition of water to raise the water content of the carrier
to 30-60% by weight results in more efficient separation of the tar from
the carrier.
Steam under a pressure of at least 200 psi is fed into the
carrier through a pair of parallel inlet pipes 15 at a first steam injec-
tion station generally indicated at 16. The pipes 15 are supported at one
end by stands 17, which are mounted on platforms 18 on the sides of the
conveyors 3, 9, and 10 The platforms 18 extend along substantially the
entire length of the apparatus for supporting various elements of such ap-
paratus. The pipes 15 extend inwardly over substantially the entire width
of the conveyor 3. A plurality of perforated U-shaped pipes 19 (Figure 4)
extend downwardly from the pipes 15 along their length into the layer 6 of
particulate carrier. The perforations (not shown) are provided in the areas
of the pipes 19 which are located in the layer 6 of carrier for discharging
high pressure steam horizontally in all directions. Actually, four vertical
rows of openings at 90 to each other are sufficient. The pipes 19 are
interconnected near their top ends by a cross bar 20.
Following injection of steam into the carrier, the carrier is
subjected to the action of a plurality of striker blades 21 at a first
striker station generally indicated at 22. With reference to Figure 5,
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each striker blade 21 is defined by a segment of a circle, with a concave
groove 23 therein. Four striker blades 21 extend outwardly in a single
plane from a central shaft 24. The blades 21 define a row of circles ex-
tending substantially completely across the path of travel of the carrier
layer 6. The blades 21 are at 90 to each other, and rotate counterclock-
wise in the direction of arrows 25 (Figure 4) which is reverse to the
direction of movement (arrow 26) of the conveyors 3 and 9, and of the car-
rier layer 6. The shaft 24 extends between the platforms 18, and is driven
by a motor 27.
A sleeve 28 is disposed on each side of each group of four
blades 21. The sleeve 28 is fixed relative to the shaft 24 and supports
one arm 29 of a generally L-shaped scraper 30. A diagonal brace 31 extends
between the arm 29 and the other arm 32 of the scraper 30. The arm 32 of
the scraper 30 is supported by a frame 33 of a transversely extending con-
veyor 34. The conveyor end of the arm 32 is integral with a ramp 35 which
extends across the transverse row of blades 21 mounted on the shaft 24.
When the blades 21 pass through the particulate carrier, they pick ùp tar.
The blades 21 then pass between the arms 32 of the scrapers 30. Because
there is very little clearance between the blades 21 and the scraper arms
32, the tar is scraped from the blades and flows down the ramp 35 to the
transverse conveyor 34. Tar is carried by the conveyor 34 to one side of
the apparatus where the tar is removed by means of a scraper 36 and de-
posited on another longitudinally extending conveyor 37. The conveyor 37
discharges the tar from the apparatus for further processing or refining.
During separation, water is fed continuously through pipes 38 and 39 onto
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the area where the blades 21 pass through the scrapers 30, and through pipes
40 and 41 onto the conveyor 34 to facilitate removal of tar from the blades
21 and from the conveyor 34.
Following the first striking action, the particulate carrier is
subjected to a second steam impregnation step at a second steam injection
station generally indicated at 42, and then to the action of additional
striker blades 21 at a second striking station 43. The second striking
step is followed by removal of tar-containing froth from the top of the
carrier layer 6 at a first froth removal station 44 through suction nozzles
45. The nozzles 45 are in a row across the path of travel of the carrier
layer 6, and are mounted on the lower ends of pipes 46 (Figure 4). The
pipes 46 extend downwardly from a transversely extending pipe 47, which
carries froth to a discharge pipe 48 (Figures 2 and 3). The pipe 48 con-
veys the froth to filtering and refining facilities (not shown).
The particulate carrier layer 6 is then subjected to a third
striking action at a third striking station 49, a second froth removal
action at a second froth removal station 50 and a fourth striking action at
fourth striking station 51. Following the final striking action, heat is
recovered from the carrier at a heat recovery station 52. The heat recovery
station 52 (Figures 3 and 4) includes a cold water inlet pipe 53 and a hot
water outlet pipe 54. The pipes 53 and 54 are mounted on a transversely
extending frame. The frame is defined by posts 55 on the platforms 18, a
cross-bar 56 extending between such posts 55, and longitudinally extending
arms 57 for supporting such pipes 53 and 54. A plurality of pipes 58 (not
shown) extend downwardly from the pipes 53 and 54 into the carrier layer 6,
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and horizontal pipes 59 interconnect such pipes 58. Thus, the pipes 58
and 59 form a grid structure. Water flowing through such pipes 58 and 59
is heated, and the heat thus recovered can be used in other parts of the
apparatus or as a source of energy for operating other parts of the appa-
ratus.
Upon leaving the heat recovery station 52, the conveyor 3 passes
beneath a scraper 60 for removal of the carrier layer 6. At the same time
carrier is removed from the conveyors 9 by scrapers 61. The carrier is
discharged to a transversely extending conveyor 62 for removal from the
apparatus. As mentioned hereinbefore, the trailing or discharge end of
the conveyor 3 is elevated with respect to the horizontal plane containing
the main portion of the conveyor. The elevated discharge end results in a
thinner layer of carrier passing beneath the scraper 60.
While the striker blades illustrated in the drawings are solid,
it will be appreciated that steam can be passed through such blades under
pressure into the carrier to facilitate tar separation. It will also be
appreciated that the term "striking" used herein means subjecting the par-
ticular carrier to a shearing action using revolving blades. Obviously,
the tar-containing carrier can be subjected to additional striking and froth
removal operations. However, there will come a time when repeated striking
operations fail to remove sufficient tar to justify such operations.
