Note: Descriptions are shown in the official language in which they were submitted.
CA 02647855 2009-01-15
Jan Kruyer, Thorsby, AB. Canada
for very small separation equipment or may be as thick as 3 centimeters in
diameter
or larger for very large commercial oil sands separation units. The spaces
between
surfaces of sequential wraps may vary widely depending upon the application
and on
the mixture to be separated. These spaces may be as small as 10% of the cable,
filament or wire diameter or smaller, or as large as 10 cable, filament or
wire
diameters.
FIG. 6a shows an internal cross sectional view of two agglomerator drums
and shows the path of endless cable wraps 600 over drums 613 and 639 and over
support rollers 606 and 607 in bitumen removal zones. In these zones, bitumen
may
be removed by combs or by squeeze rollers (not shown). As in previous Figures,
these endless cable wraps 600 are shown in FIG. 6a as a dashed line to
indicate that
the wraps form a screen that has apertures in the form of slits between the
wraps.
Since the screen uses a multi wrap endless cable, guide rollers are needed to
prevent
the cable from running off the rollers but these are not shown for simplicity
of the
Figure. The top drum 613 is filled with oleophilic tower packings and the
bottom
drum 639 is partly filled with a bed of oleophilic balls. This serves to
illustrate that
both packings and balls may be used in the same separator if desired. Mixture
to be
separated enters the top drum through a central inlet 690 from a feed pipe
(610 of
FIG. 6b) and passes through an apertured cylindrical wall 614 to prevent
oversize
particulate material from entering the zone of the drum filled with tower
packings.
The separating mixture passes through the zone filled with tower packings and
then
leaves through the outside cylindrical wall at the bottom of the top drum. As
illustrated in the Figure, the outside cylindrical walls of these drums are
not made
from perforated steel but are formed from by a multitude of notched cross bars
641.
These notched bars are attached to the drum end walls and may be supported by
internal baffles, as well, as detailed in FIG. 5b. The tailings (not shown)
from the top
drum fall into the bottom drum past the notched bars 641 along the top of the
drum
639 and mix with the bed of balls in the bottom drum for the removal of
additional
bitumen by bitumen agglomeration and bitumen kneeding that takes place in this
bed.
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Jan Kruyer, Thorsby, AB. Canada
The final tailings pass into a tailings receiver 620 to be removed as the
final tailings
621 of the separation process.
FIG. 6b is a side view of FIG. 6a. without showing the tailings receiver.
Mixture to be separated flows into the interior of the revolving upper drum
602
through a feed pipe 610 and tumbles inside the central portion which is
bounded by a
cylindrical apertured wall (614 of FIG 6a). Aqueous phase including
particulate
solids and bitumen that are smaller in size than the apertures of this
apertured wall
614 pass through this wall into the annular area of the drum filled with tower
packings, where bitumen particles are increased in size by agglomeration as
the
mixture comes in contact with the oleophilic surfaces of the tower packings.
Oversize in the form of solid particulates that are larger than the apertures
of the
apertured cylindrical wall 614 accumulate in the inside central portion and
leave as
oversize 653 through the funnel outlet 650 which prevents aqueous phase from
leaving with the oversize before it flows through the apertured wall. Auger
flights
mounted on the inside funnel wall remove oversize but minimize the loss of
water or
bitumen. Alternately, a feed of mixture to be separated 652 may be introduced
into
the funnel cone 650 opening instead of through the feed pipe 610. The upper
drum
may be mounted on a turn table bearing 648 and may be driven by a gear 655
that
engages gear teeth of the bearing 648. This gear 655 is mounted on a shaft 656
supported in pillow block bearings 657 that are mounted on structural beams
654 and
is driven by a motor or motor and gear box (not shown). The turn table bearing
648
also is mounted on structural beams 649 to support the rotating drum 602. The
use of
a turn table bearing for the drum support provides for easy access of mixture
feed to
the drum and also for easy removal of oversize 653 from the central portion of
the
drum. Alternately, slewing rings mounted on the drum side walls may be
supported
by ring rollers which may be driven, and/or the drum may be driven with the
use of
sprocket teeth and a roller chain.
The bottom drum 603 of FIG. 6b may be supported with a turn table bearing,
or a central shaft with central heavy wall pipe may be used as disclosed with
FIG. 5a.
In this case the central pipe 645 is mounted on a central shaft 644 similar to
FIG. 4a,
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Jan Kruyer, Thorsby, AB. Canada
4b or 5a. and the shaft is mounted in pillow block bearings 646 which are
supported
by structural beams 647. Mixture that leaves from the bottom of the top drum
602
will contain less bitumen than mixture entering the top drum and may also be
smaller
in particle size. This mixture falls onto the top of the bottom drum 603 and
enters the
interior of the drum 603 through its apertures at the top between the cross
bars (641 of
FIG 6a).
Again referring to FIG. 6a, this Figure illustrates that mixture leaving the
bottom of the top drum, after passing through the endless cable screen, can
fall
directly into the bottom drum 639 through the top of that drum 639 and does
not
encounter an endless cable screen as it passes through the slits or apertures
between
the notched bars 641. From there the mixture encounters the bed of balls in
the
bottom drum and gives up most of its residual bitumen, for deposit on the
endless
cable screen around the bottom of this drum, as final tailings leave the
bottom drum
and flow into the tailings receiver 620 for removal by removal means 621 . As
indicated by the directional arrow 601, bitumen leaving from the bottom drum
adheres to the endless cable screen and is removed in a bitumen removal zone
indicated by the support roller 606. Similarly, bitumen leaving from the top
drum
adheres to the endless cable screen and is removed in a bitumen removal zone
indicated by the support roller 607. Bitumen removal from endless cable wraps
has
already been described in detail in the present patent or in the co-pending
patent
entitled "Endless Cable System and Associated Methods".
For short drums the end walls of the drums 602 and 603 of FIG. 6b may
provide the required support for the endless cable screen without the need for
the
baffles described with FIG. 4b and 5b. In this case, notched cross bars may be
directly welded to the end walls. Rectangular holes, precut into the end
walls, may to
accept these notched cross bars. These rectangular holes are approximately the
same
size as the ends 532 of notched bars of FIG. 5d. The shape of these cross bars
are
similar to the cross bars of FIG. 5d and 5e.
FIG. 7a shows in schematic form a method for heating with live steam
bitumen captured by endless cable wraps prior to removal of bitumen from the
wraps
CA 02647855 2009-01-15
Jan Kruyer, Thorsby, AB. Canada
for an inclined cable flight. Bitumen collected in a separation zone by an
endless
cable screen from bitumen containing mixtures at near ambient temperature is
very
viscous and may require considerable force and/or roller pressure to remove it
from
the cable wraps in bitumen removal zones. This may also add significant stress
to the
devices used to drive the revolving endless cable(s). Bitumen on the wraps,
however,
may be heated in a confined path after leaving a separation zone to facilitate
removal
in the bitumen removal zones. Heating bitumen while on the cable wraps is
convenient and may also simplify subsequent handling of the removed bitumen. A
side view of the cable wraps 701 is illustrated by the heavy dashed line and
the
direction of wrap movement is shown by the arrow 702. A confined space is
provided by a housing 703 that encloses the cable wraps. Bitumen 704 on the
wraps
fills the housing 703 which serves as a cold bitumen accumulator due to
adhesion of
bitumen to the stationary housing walls above and below the moving cable wraps
701
to form a cold bitumen zone 705 which may have a temperature only slightly
higher
than the temperature of the separating mixture. If slightly higher, this
increase in
temperature is caused by conduction of heat by the housing 703 from a hot
bitumen
zone 706. Live steam 707 is sparged through the housing 703 into the confined
path
708 to create a hot zone 706 of bitumen heated by steam 707 sparged into the
bitumen
directly or into an enlarged heating zone 709 . The cold zone 705 filled with
viscous
low temperature bitumen serves to prevent the flow of steam in a direction
opposite to
the direction 702 of movement of the cable wraps 701. Cold bitumen 704 is
carried
into the hot zone 706 by couette flow and is heated by live steam 707. Warm
bitumen
has a much lower viscosity than cold bitumen and couette flow and steam
pressure
causes the flow of warm bitumen from the hot zone 714 towards the rollers 710
and
711 and into the bitumen product receiver 712 to form a warm bitumen product
713.
In fact, couette flow in the cold zone can create pressure in the hot zone to
force
warm bitumen out of the enclosure towards the rollers. The stationary housing
703, in
conjunction with the moving cable wraps 701 act like a combined couette and
pressure flow pump that forces heated bitumen and condensing steam from the
hot
bitumen zone 714 to the upper outlet 716 of the confined space to flow towards
the
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Jan Kruyer, Thorsby, AB. Canada
bitumen product receiver 712 while cold bitumen 705 of high viscosity at the
inlet
715 of the confined space prevents the downward flow of heated bitumen in a
direction opposite to the direction of wrap movement 702. Any significant
amounts
of warm bitumen remaining on the cable wraps are squeezed off by the rollers
710
and 711 or may be removed by a comb (not shown here but see FIG. 8 c,d,e) and
flow
into the bitumen product receiver 712 to be removed as the bitumen product
713.
Roller 710 and/or roller 711 may be chilled to cool down the cable wraps
before these
enter a subsequent separation zone. Chilling of the rollers, if desired, may
be
accomplished by the use of hollow roller rollers and shafts that allow entry
of cool
water or refrigerant into the rollers through one shaft end and removal of
warmer
water or refrigerant through the other shaft end of each roller. Suitable
rotary seals
may be provided on these roller shafts to prevent spillage or leakage of water
or
refrigerant.
Sparging condensing steam into a liquid filled enclosure can be very noisy due
to the implosions of steam bubbles in a colder liquid. The enlarged heating
zone 709
may be designed to reduce this noise of condensing steam.
FIG. 7b shows a graph of viscosity as a function of temperature for Athabasca
bitumen. The viscosity versus temperature relation of oil sand bitumen varies
somewhat with the location of the ore deposit but in all cases this
relationship shows
a dramatic reduction in viscosity as a function of temperature increase
especially in
the range between 0 and 100 degrees centrigrade. As seen from FIG. 7b, raising
the
temperature of bitumen by 40 degrees, from 20 degrees centigrade to 60 degrees
centigrade results in viscosity reduction from about 470,000 cp to about 4,000
cp
representing two orders of magnitude of viscosity reduction. In many cases,
even a
ten or twenty degree increase in bitumen temperature in the confined space is
sufficient to simplify bitumen removal from the cable wraps.
FIG. 8a shows a method for heating with live steam bitumen captured by
endless cable wraps prior to removal of bitumen from the wraps for a vertical
or
nearly vertical cable flight. It is similar to FIG. 7a in which couete flow
causes
bitumen 801 on the cable wraps 802 to enter the enclosure 803 in the direction
shown
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Jan Kruyer, Thorsby, AB. Canada
by the arrow 814. After entry into the enclosure, the enclosure walls collect
bitumen
to form a cold zone 804 where viscous bitumen comes in contact with stationary
enclosure walls and flows upward at an average velocity that is less than the
upward
velocity of the cable wraps 802 and thus forms a plug of viscous bitumen that
prevents the downward flow of low viscosity bitumen from a hot zone 807 that
has
been heated by steam 805 sparged into the hot zones through the walls of the
enclosure 803 directly into the hot zone or in a mixing or heating chamber 806
where
steam mixes with bitumen before the heated bitumen flows into the hot zone.
Bitumen flowing from the cold zone into the hot zone due to couette flow, and
the
entry of condensing steam into the hot zone forces bitumen out of the hot zone
807
through outlet 808 to then flow by gravity into bitumen product receiver 812
from
where it is removed as a warm bitumen product 813. A main roller 809 and a
squeeze
roller 810 may be used to squeeze warm bitumen from cable wraps and cause this
bitumen to flow into the bitumen receiver 813. Alternately, bitumen may be
removed
from the cable wraps by means of a set of two engaged combs illustrated in
FIG. 8c,d
and e. The enclosure may be insulated (not shown) to reduce heat loss and the
walls
of the enclosure may be made movable to make adjustments in the chamber
dimensions to accommodate any desired flow and accumulation of cold bitumen
into
the enclosure without spillage. Furthermore, the movement of these walls may
be
done under process control based on the amount of bitumen accumulating in the
cold
zone.
When live steam at 15 psig (about 100 kPag) is used for heating of viscous
bitumen from 30 degrees centigrade to 80 degrees centigrade in the confined
path of
FIG. 7a or 8a about 1 kg of steam is needed to heat about 20 kg of bitumen,
resulting
in a 125 fold change in bitumen product viscosity from 100,000 cp. to 800 cp.,
making bitumen removal from the cable wraps very easy but increasing the water
content of the product by about 5%. In many cases such a drastic viscosity
change is
not needed to achieve effective removal of bitumen from the cable wraps, and
only a
five or ten fold reduction in bitumen viscosity may suffice, requiring less
live steam
and resulting in less condensed water in the product.
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Other methods may be used to heat bitumen in a confined path without adding
water to the bitumen product. This is illustrated in FIG. 8b where other
sources of
heating are used. As in FIG. 7a and 8a, bitumen 821 may be carried into a cold
zone
822 of a confined path enclosure by revolving cable wraps and may flow into a
hot
zone 823 enclosed by a source of heat 824 which conducts heat into the hot
zone 823.
The source of heat may be one or more steam coils, infrared heaters, electric
resistance heating elements, high frequency induction coils, or microwave wave
energy sources. Similar to the illustrations of FIG. 7a and 8a, reduced
viscosity
bitumen product flows from the hot zone into a bitumen product receiver 825 .
Warm bitumen may be removed by a set of rollers, for example, 826 and 827
and these rollers may be cooled or chilled to cool the cable wraps passing
between
such grooved rollers. Cooled or chilled rollers generally allow warm bitumen
to flow
away from the pinch point between cool rollers into bitumen receivers because
of the
low conduction of heat in bitumen. The very close contact between cool roller
surfaces and warm cable wraps for a more extended time (see contact distance
between wraps and roller 826 surface in FIG. 8b) tends to cool the wraps
significantly
but the removed bitumen remains relatively warm.
A set of combs may be used instead of, or in addition to, squeeze rollers to
remove bitumen from the wraps. Such combs are illustrated in FIG. 8c, d and f.
One
comb is illustrated in FIG. 8c consisting of a strip of wear resistant metal,
high
density polyethylene or other material which has been formed, cast, cut or
milled with
slots that are contoured at the root 850 to accept a round cable and with
tines 851 that
keep cable wraps spaced and aligned. As shown in FIG. 8e, when two such combs
are placed over each other with the tines in opposite directions, the tines
overlap in a
region 853 of overlap while providing openings for cable wraps 852 to pass.
Most of
the bitumen adhering to these cable wraps is scraped off the wraps by the
overlapping
combs. During operation the cable wraps will wear against the combs and deepen
the
slots due to abrasion but most or some of this wear can be accommodated by
making
the overlap of the combs adjustable to maintain close contact between cable
wraps
and the comb surfaces. Bitumen product scraped from cable wraps may flow into
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Jan Kruyer, Thorsby, AB. Canada
DESIGN OF ENDLESS CABLE MULTIPLE WRAP
BITUMEN EXTRACTORS
RELATED APPLICATIONS
This application is related to Canadian patent application number 2,638,474
filed 6 August 2008 entitled "Isoelectric Separation of Oil Sands", Canadian
patent
application Number 2,6538,550 filed August 7, 2008 entitled "Hydrocyclone and
Associated Methods", Canadian patent application number 2,638,551 filed August
7,
2008 entitled "Sinusoidal Mixing and Shearing Apparatus and Associated
Methods", Canadian patent application number 2,638,596 filed August 6, 2008
entitled "Endless Cable System and Associated Methods", and Canadian patent
application number 2,644,793 filed October 29, 2008 entitled "Electrophoresis
of
Tailings Sludge using Endless Cable Wraps"
FIELD OF THE INVENTION
The present invention relates to process devices and methods for separating
aqueous mixtures containing oil sand bitumen and discloses apparatus design
and
process considerations for the recovery of bitumen from such mixtures.
Accordingly,
the present invention involves the fields of process engineering, chemistry
and
chemical engineering.
As of the date of this filing, the present inventor has spent 34 rewarding and
frustrating years of his professional life on the development of oleophilic
sieve
technology. Getting on in age he wishes to leave a record and teach to those
after him
an understanding of the great potential of this process for cost effective and
environmentally responsible development of the Canadian oil sands. These oil
sands
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CA 02647855 2009-01-15
Jan Kruyer, Thorsby, AB. Canada
were placed here for a purpose. When properly developed this resource will
yield
more oil than any other world oil reserve and will be of great benefit to many
in the
years to come.
BACKGROUND OF THE INVENTION
A detailed description of oil sands, tar sands or bituminous sands deposits
and
of the processing of these sands to produce bitumen is provided in the above
referenced applications. In Northern Alberta, there presently are several
commercial
facilities, which extract bitumen from mined oil sands using the commercial
Clark
Hot Water Extraction Process. These are very large plants, some of them
producing
more than 300,000 barrels of oil products per day each.
In accordance with the first step of one commercial application of the Clark
process, the oil sand is mixed with hot water, air and a small amount of
"process aid"
(usually NaOH) to produce an aqueous slurry in which sand grains, fines,
bitumen
droplets and air bubbles are suspended in hot water. This slurry is then
diluted with
water and introduced into a thickener-like vessel known as a "PSV" or primary
separation vessel where bitumen droplets, attached to air bubbles, rise to the
top and
are skimmed off as the "primary bitumen froth" product. Most of the coarse
sand,
together with water, some fines, some bitumen, some process aid, and some
surfactants produced by reaction of process aid and oil sand, sink and leave
the PSV
through a bottom outlet. This stream is referred to as "primary tailings". A
large
portion of the fines and some non-buoyant bitumen collect in the mid section
of the
PSV contents. An aqueous drag stream from this middle zone, termed "middlings"
is
withdrawn and introduced into a series of induced air flotation cells. Here
the
middlings are contacted with a flood of minute air bubbles. Bitumen particles
of the
middlings attach themselves to these air bubbles and cause bitumen to float to
the top
of the cells where the aerated bitumen is skimmed off as the "secondary
bitumen
froth" product. A tailings product, referred to as "secondary tailings",
leaves from the
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Jan Kruyer, Thorsby, AB. Canada
bottom outlet of the flotation cells. These secondary tailings comprise water,
some
fines, some bitumen, some process aid, and some surfactants.
The primary and secondary tailings are combined and discharged onto the
shore of a large tailings pond. Here the coarse sand grains settle out and
form a
beach, leaving a mixture of bitumen and fine solids in water, process aid and
surfactants. This mixture flows into the tailings pond where mineral fines,
being
negatively charged due to the presence of chemical process aid and
surfactants, settle.
Some water is released and rises to the top of the tailings pond whilst the
rest slowly
settles towards the bottom of the pond to form a mineral fines structure
somewhat like
a house of cards with water trapped in between. This is known in the industry
as
"tailings pond sludge", "sludge" or "fine tails" and comprises fines, a large
amount of
water, some bitumen and small quantities of NaOH and surfactants. The mineral
content of this sludge ranges from less than 10% to about 40% by weight,
depending
on the time that has passed since it was deposited into the pond. For example,
the
40% solids containing sludge is mature sludge and has probably resided in the
ponds
for about 35 years. The volume of sludge so formed is huge, in the order of
about 2.5
barrels of sludge for every barrel of bitumen produced.
Most of the process water used for Alberta mined oil sands development
comes from the Athabasca river. According to Alberta government reports, 66%
of
the assigned annual flow of this river is allocated to oil sands development.
By the
year 2005 the annual amount of water used in the oil sands had reached 360
million
cubic meters. Only 10% of that was returned to the river, leaving 324 million
cubic
meters of water accumulating that year into tailings ponds. Currently these
tailings
ponds occupy an area exceeding 50 square kilometer and this area is expected
to
triple in size in the next two decades with current projected expanded oil
sands
development. By the year 2005 a total of about 2,600 million barrels of
bitumen had
been produced from the oil sands, and this had resulted in 650 million cubic
meters
of tailings pond sludge. That is enough sludge to fill a ditch 10 meters deep,
10
meters wide and 6500 kilometers long; further than from Victoria to Halifax,
all the
way across Canada The ponds are massive structures surrounded by dykes
towering
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Jan Kruyer, Thorsby, AB. Canada
over the local topography. It has been reported that large amounts of toxic
water leak
through these dykes and leave the ponds to flow into the environment.
Eventually all
the tailings ponds will have to be reclaimed and the sludge cleaned up to
restore each
mine site to a condition similar to or better than before mining started, to
provide a
suitable natural habitat. For that reason it would be desirable that sludge
solids
deposited on the land at the end of an oil sand lease should contain as little
water as
possible to make the reclaimed land able to support the weight of a man, of a
vehicle
or to support animal life.
Considering that the Clark process has achieved less than 90% average
bitumen recovery from mined oil sands since 1968, the total amount of bitumen
stored in the tailings ponds to date exceeds 200 million barrels. Currently
that is
considered to be lost or discarded bitumen. Water from pond sludge can not be
recycled to the Clark process unless its solids content is reduced to about 4%
by
weight or less, and then fresh water from the Athabasca, containing
essentially no
solids, is mixed with this recycle water for use in the process. It is
anticipated that at
the end of each mined oil sands lease, a huge amount of toxic water will be
left
behind in end pit lakes because much of this water contains too much mineral
to be
recycled in the Clark process. Kruyer technology for extracting bitumen from
mined
oil sand slurries is much more tolerant of fines and can efficiently
accommodate a
process water recycle that contains about 10% solid fines by weight.
For processing oil sands, the Clark process uses at least two stages of
bitumen
flotation to recover sufficient bitumen to make the process commercially
viable.
Caustic soda is required to enhance bitumen flotation by giving the oil sand
fines a
negative electrical charge so that these fines will repel each other, to thin
the fluid in
the separating vessels to allow bitumen droplets attached to air bubbles and
rise to the
top of these vessels fast enough to achieve the desired bitumen recovery
within the
allowable residence time. Normally during bitumen extraction, the allowable
residence time for separation in the primary vessel (PSV) is about 30 to 60
minutes
and in flotation cells is again about the same for a total residence time of
about 70 to
100 minutes. Hence, bitumen froth flotation is a very slow process that
requires large
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Jan Kruyer, Thorsby, AB. Canada
amounts of heat, large amounts of fresh water, while producing vast amounts of
toxic
tailings that lock in large amounts of water for a very long time. The
resulting tailings
ponds take several years before any significant amount of clarified water can
be
recycled to the Clark process to reduce its fresh water demand.
When the tailings of a Clark process flow into a tailings pond, tailings sand
and some fines are deposited on the beach of the pond and water rises to the
top of the
pond after the remaining fines collect into layers of sludge at a given depth
in the
pond. The net effect of the removal of sand and water from the tailings is
that the
percent bitumen content in the resulting sludge layers of the pond is about an
order of
magnitude greater than the bitumen content of the original tailings deposited
at the
shore of the pond. In essence, a tailings pond serves as a very large bitumen
concentrator. In many cases, and over time, some of the bitumen particles
disengage
from the sludge layers and form bitumen mats that float inside the sludge
layers.
Most of this bitumen was too heavy to float in the Clark process since it
contains
some captured solids. It floats inside the sludge and finds a level that is a
function of
its density with respect to the density of the sludge layers in the pond.
Recovering
bitumen from tailings pond sludge by froth flotation is not viable since such
flotation
also brings up huge amounts of dispersed clay that are difficult to keep
separate from
the bitumen product. Bitumen flotation requires sludge dilution with water and
the
input of heat, air and chemicals to achieve any acceptable degree of bitumen
froth
recovery. Currently only the Kruyer process is able to economically recover
bitumen
from tailings pond sludge at the year round pond temperature of about 12
degrees C
without bringing up large quantities of clay and without the need for dilution
water or
chemicals.
From the above provided information it appears clearly advantageous to
develop a better method of bitumen extraction from oil sands that can do the
separation faster, that reduces the production of toxic sludge, which uses
less fresh
water, is more tolerant of fines in the process water and requires less energy
for
bitumen extraction. Pilot test work has confirmed that the Kruyer bitumen
screening
process can recover bitumen from mined oil sand slurries much faster than the
Clark
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Jan Kruyer, Thorsby, AB. Canada
process. It does not produce a sludge that is very toxic, it uses less fresh
water and is
more energy efficient, which computes into lower green house gas emissions.
Unlike
the 70 plus minute residence time required by the Clark process for extracting
bitumen, the Kruyer process is about an order of magnitude faster and takes
between
2 and 10 minutes to achieve the same bitumen recovery yield. Therefore, when
commercially implemented in due time this process is expected to significantly
reduce the cost of producing a barrel of bitumen from oil sand ore with less
damage
to the environment.
SUMMARY OF THE INVENTION
The present invention relates to improvements to the 34 year old Kruyer
bitumen sieving process for bitumen recovery from streams that contain oil
sand
bitumen. Such streams include oil sand slurries, process streams of a
commercial oil
sands plant that contain bitumen, fresh tailings pond sludge and mature
tailings pond
sludge that has settled and compacted for a few decades.
Several of the original Kruyer patents were based on thin oleophilic apertured
sieve (mesh) belts that were made from plastic, had cross members and were
used to
captured bitumen from bitumen containing streams, such as oil sand slurries,
middlings, tailings and tailings pond sludge. These mesh belts worked well in
the
pilot plant and confirmed the merits of Kruyer technology but did not last
more than a
few weeks of continuous operation. Residence times, bitumen recovery yield,
operating temperature, water requirements and energy demands could be
established
accurately but long duration testing was not possible with these belts.
More rugged metal belts were subsequently tried as substitutes for the above
mesh belts. The metal belts consisted of multiple pre-punched strips of metal
bent
into a truncated sinusoidal shapes. Cross rods were passed through the punched
holes
in these sinusoidal strips to allow these strips and rods to act like a
multitude of
sequentially joined hinges to form strong flexible conveyor belts.
Alternately, metal
coils were used as multiple hinges by the use of cross rods that joined
succeeding
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Jan Kruyer, Thorsby, AB. Canada
coils to make long belts that were flexible and very strong and long lasting.
Both the
strip type and the coil type of metal belts are standard belts used for
commercial
conveyors in bottling plants and in a large variety of other warehouse and
plant
operations that require conveyance of goods or components. These belts are
much
more rugged than mesh belts and would have stood up well for long duration
testing
in abrasive environments; but these belts were too thick for effective bitumen
extraction from oil sand streams. It turned out that these belts could capture
bitumen
from the feed mixture streams but would not effectively release the captured
bitumen
quickly enough to produce a good quality bitumen product, and would tend to
entrap
too much undesirable solids and water in the bitumen product. This was further
aggravated when bitumen in the feed stream contained entrapped air.
Based on that prior experience, much time and research was then devoted to
the development of relatively thin apertured oleophilic belts that were very
rugged
and long lasting but yet were very flexible and would capture bitumen
efficiently
from a bitumen containing stream in separation zones and would quickly release
this
bitumen in bitumen removal zones. This was done to foster commercial
development
of bitumen extraction apparatus and methods that would allow efficient bitumen
extraction from oil sand streams using very short residence times. Such
development
was encouraged by the prior pilot plant discovery that screening bitumen from
a
mixture with an oleophilic sieve or oleophilic apertured screen was much
faster than
froth flotation of bitumen in a settling vessel. In other words, the required
apparatus
residence of a mixture for bitumen sieving had turned out to be much shorter
than the
apparatus residence time required for bitumen froth flotation. As a result of
these
findings, a suitable oleophilic apertured belt was developed that used an
endless cable
wrapped multiple times around two or more revolving grooved rollers to form a
sieve
or apertured screen. The wraps of such endless cables were designed to collect
bitumen from a bitumen containing aqueous mixture, allowing the resulting
bitumen
reduced mixture to flow through the slits or apertures between sequential
wraps to
become the tailings of separation.
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Jan Kruyer, Thorsby, AB. Canada
Steel cables and multi strand ropes are in common use in industry, are strong,
flexible and abrasion resistant, generally are oleophilic and have performed
well
during long operation cycles in many applications. As thus described, my
research
has resulted in the development of a new art by making these endless cables
take the
form of oleophilic sieves or apertured screens in which the cable wraps are
oleophilic
to capture bitumen and in which the spaces between the cable wraps become the
apertures for the passage of bitumen reduced tailings. The size and
construction of the
cable, rope or wire for the multi wrap apertured screen can be selected for
optimum
strength and flexibility. The wraps can be suitably spaced to form the desired
aperture width and allow the separating mixture to pass through these
apertures after
bitumen has been captured from the mixture by the oleophilic wraps. In this
new art,
guide rollers are provided which redirect the last wrap from one edge of the
rollers to
the other edge of the rollers to seamlessly become the first wrap, and prevent
the
cable, rope or wire from running off the rollers, etc. The resulting apertured
oleophilic endless belt or sieve does not have cross members and this makes
the rapid
removal of bitumen easy to accomplish by the use of combs or squeeze rollers.
In
contrast, cross members prevent the use of combs and require wider space
between
two rollers to allow the passage of belt cross members, making bitumen
squeezing
less effective. In the case of multiple cable wraps without cross members,
grooves in
one or both rollers provide for convenient passage of cable wraps between the
roller
surfaces while leaving minimal room for the passage of bitumen past the
rollers. An
isometric drawing of a multiwrap cable belt is shown in FIG. 1 and this belt
is
disclosed and claimed in detail in co-pending Canadian patent application
number
2,638,596 filed August 6, 2008 entitled "Endless Cable System and Associated
Methods". The concept of a revolving endless cable belt with multiple wraps
has
application in many fields of separation technology described in the above
referenced
patent applications. One specific application is disclosed in co-pending
Canadian
patent application entitled "Electrophoresis of Tailings Sludge using Endless
Cable
Wraps", filed October 29, 2008. In this application a DC current is used to
separate
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Jan Kruyer, Thorsby, AB. Canada
solids from tailings pond sludge using a revolving endless cable sieve, screen
or belt
without cross members.
Squeezing or combing bitumen from cable wraps removes most of the
bitumen and yet leaves a thin layer of bitumen on the wraps at all times.
Eliminating
cross members and using endless ropes or wire ropes with multiple wraps also
facilitates the heating of captured bitumen on the wraps to reduce the
viscosity of this
bitumen for subsequent removal by combs or by cooled squeeze rollers in a
bitumen
removal zone. Cooling one or both rollers immediately after bitumen removal
tends
to cool down the bitumen-reduced wraps and can improve subsequent bitumen
capture by the wraps in a separation zone
As thus described, the new concept of apertured multi wrap endless cable
belts is opening up a whole new area of separations engineering such as in the
separation of mixtures by size, by magnetic attraction, by electrical
attraction or
repulsion by direct voltage, or particle vibration by alternating voltage, or
of many
other types of separation. It also provides a fertile field for technology
development
devoted to the preparation of mixtures for such separations. Applications
suitable for
use in these field are disclosed in several filed co-pending patent
applications
referenced above at the beginning of this application. These are further
detailed in
this present application, which teaches and gives guidance to apparatus
design,
applications and methods for using the endless cable belt concept for bitumen
recovery from streams containing bitumen.
There have thus been outlined rather broadly, the pertinent features of the
invention so that the detailed description thereof that follows may be better
understood and so that the present contribution to the art may be better
appreciated.
While the focus of this disclosure is on the separation of bitumen from oil
sand
slurries and from tailings pond sludge, the instant invention has application
in the
separation of bitumen from any aqueous stream that contains bitumen or that
contains
any other type of oleophilic liquid, liquid particulates or oil wetted solids
particles.
Other features of the present invention will become clearer from the following
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Jan Kruyer, Thorsby, AB. Canada
detailed description of the invention, taken with the accompanying claims, or
may be
learned by the practice of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. Ia is an isometric drawing of a very basic endless wire rope or cable
with
wraps that form a screen described in the above referenced co-pending patent
application entitled: "Endless Cable System and Associated Methods".
FIG. 2a is a schematic drawing of a sloping endless cable belt for bitumen
capture and removal using 6 separation zones and 6 bitumen removal zones.
While
this is not shown in the drawing, the tailings from one zone may be used as
the
mixture feed for another zone if more than one stage of separation is desired.
FIG. 2b is a schematic drawing of a sloping endless cable belt for bitumen
capture and removal using 2 separation zones and 2 bitumen removal zones, one
separation zone and one bitumen removal zone along the top flight, and one
separation zone and one bitumen removal zone along the bottom flight, wherein
the
mixture to be separated is provided from a distributor above the top flight
and from a
distributor above the bottom flight.
FIG. 2c is a smaller scale isometric drawing of the rollers and of the endless
cable belt of FIG. 2b providing a perspective view to provide more detail for
the
methods of FIG. 2b and FIG. 2d
FIG. 2d is similar to FIG. 2b in providing 2 separation zones and 2 bitumen
removal zones but in this case the tailings from the top flight flow into an
agglomerator wherein residual bitumen particles of these tailings are
increased in size
before flowing to the bottom flight for capture by the endless cable belt
along the
bottom flight. Alternately a distributor may be used instead of an
agglomerator above
the bottom flight to provide two stage separation without agglomeration.
FIG. 3a is a schematic drawing of an multi wrap endless cable belt for
separations using a sloping top flight for bitumen capture and removal, and a
bottom
CA 02647855 2009-01-15
Jan Kruyer, Thorsby, AB. Canada
flight which supports an agglomerator for residual bitumen particle
enlargement,
followed by bitumen capture and removal by the bottom flight.
FIG 3b is an isometric drawing of the endless cable wraps and the three
support rollers of FIG. 3a.
FIG. 4a to 4e provide details for the construction of an agglomerator and for
roller support.
FIG. 4a is a small scale isometric drawing of the main central shaft of the
drum of FIG. 4b, using a heavy wall pipe to provide the required core strength
for the
drum. Since the drum has an apertured cylindrical wall, and may be partly
filled with
heavy balls, a strong core is needed to support the cylindrical drum wall with
tie bars
or baffles and prevent deformation of the apertured wall under the weight of
the balls.
FIG. 4b is as cross sectional drawing of suitable internals for an
agglomerator
drum.
FIG. 4c is an internal cross sectional view of an agglomerator drum through
section A-A of FIG. 4b but not showing the support brackets between pipe core
and
cylindrical drum wall. The drum is partly filled with steel and plastic or
rubber balls
for agglomeration of bitumen from the mixture prior to separation.
FIG. 4d is an internal cross sectional view of an agglomerator drum through
section A-A of FIG. 4b completely filled with light oleophilic tower packings.
FIG. 4e shown at the top of the page, is a detail showing brackets for
mounting two rollers; one roller to support the endless cable wraps and the
other to
support a squeeze roller for removing bitumen from the endless cable wraps.
FIG. 5a to 5e provide additional details for the construction of an
agglomerator drum.
FIG. 5a is an isometric drawing of an agglomerator drum for supporting
endless cable wraps.
FIG. 5b is an internal sectional view of the agglomerator showing the shaft, a
support pipe, support brackets, drum wall and the location of the notched bars
in the
cylindrical drum wall that keep the cable wraps in proper alignment.
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Jan Kruyer, Thorsby, AB. Canada
FIG. 5c is an enlarged detail drawing of a section of the agglomerator drum
wall showing notched bars mounted in the drum wall.
FIG. 5d is a detail drawing of a typical notched bar.
FIG. 5e is an alternate design of a notched bar.
FIG. 6a to 6b show two agglomerator drums supporting endless cable multiple
wraps. In this case the endless cable screen is supported by an agglomerator
drum
along the top flight and also by an agglomerator drum along the bottom flight.
FIG. 6a shows a cross sectional internal view of the two agglomerator drums
and shows the path of endless cable wraps over the cylindrical drum walls and
over
bitumen removal rollers.
FIG. 6b shows a side view of FIG. 6a.
FIG. 7a shows a method for inclined endless cable wraps to heat with live
steam bitumen captured by the wraps prior to removal of bitumen from the
wraps.
FIG. 7b shows a graph of viscosity as a function of temperature for a typical
Athabasca bitumen, showing the dramatic change in viscosity that occurs when
bitumen is heated even a few degrees, especially in the range between 10 and
100
degrees centigrade.
FIG. 8a shows a method for heating with live steam bitumen captured by
endless cable wraps prior to removal of bitumen from the wraps for a vertical
or
nearly vertical cable flight.
FIG. 8b shows a method for heating bitumen captured by cable wraps prior to
removal of bitumen from the wraps. The method for heating may be in or on a
confined path enclosure using condensing steam chambers, steam coils,
electrical
heating elements, induction heating elements, microwave energy, or infrared
energy.
The Figures and text of the endless cable belt are described herein in detail
for
an endless cable that is wrapped multiple times around rollers to form a sieve
or
screen for separation purposes. For such a multiple wrap cable, a cable guide
or
guide rollers are required to keep the endless cable from running off the
rollers.
However, a similar sieve or screen may be formed from a multitude of single
wrap
endless cables supported side by side on rollers to achieve the same purposes
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Jan Kruyer, Thorsby, AB. Canada
described herein for an endless cable with multiple wraps. In the case of
single wrap
cables, however, guides or guide rollers are not needed to keep the cables
from
running off the rollers but only combs or roller grooves are required to keep
the single
wraps properly aligned.
DETAILED DESCRIPTION
Before the present invention is disclosed and described, it is to be
understood
that this invention is not limited to the particular structures, process
steps, or materials
disclosed herein, but is extended to equivalents thereof as would be
recognized by
those ordinarily skilled in the relevant arts. It should also be understood
that
terminology employed herein is used for the purpose of describing particular
embodiments only and is not intended to be limiting
It must be noted that, as used in this specification and the appended
claims, the singular forms "a," "an," and "the" include plural referents
unless the
context clearly dictates otherwise. Thus, for example, reference to "a splice"
includes
one or more of such splices, reference to "an endless cable" includes
reference to one
or more of such endless cables, and reference to "the material" includes
reference to
one or more of such materials.
Definitions
In describing and claiming the present invention, the following terminology
will be used in accordance with the definitions set forth below. When
reference is
made to a given terminology in several definitions, these references should be
considered to augment or support each other or shed additional light.
"agglomeration" refers to increasing the size of bitumen particle in an
aqueous
mixture by means of an agglomeration drum prior to the removal of enlarged
bitumen
particles from the mixture by oleophilic apertured wall, sieve, screen, belt
or cable
wraps.
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Jan Kruyer, Thorsby, AB. Canada
"agglomeration drum" refers to a drum containing oleophilic surfaces that is
used to increase the particle size of bitumen particles in oil sand mixtures
prior to
separation. Bitumen particles flowing through the interior of said drum come
in
contact with oleophilic surfaces and adhere thereto to form a layer of bitumen
of
increasing thickness until the layer becomes so thick that shear from mixture
flowing
through the revolving drum causes a portion of the bitumen layer to slough
off,
resulting in bitumen particles that are larger than the original bitumen
particles of the
mixture. When a bed of oleophilic balls is used in the drum, these balls
agglomerate
the bitumen but also kneed the collected bitumen. This kneeding normally does
not
occur when tower packings are used in the drum.
"oleophilic apertured wall" refers to oleophilic sieve, to oleophilic
apertured
screen, to drum with oleophilic apertured cylindrical wall or to oleophilic
endless
rope or wire rope cable formed into an apertured oleophilic belt by means of
wrapping the cable multiple times around two or more rollers or drums. When
using
oleophilic apertured walls to separate bitumen from an aqueous mixture, water
and
suspended hydrophilic solids pass through the apertures of the walls or
through the
slits between sequential wraps of the oleophilic endless cable, whilst bitumen
and
oleophilic solids are captured by the oleophilic wall surfaces or cable wraps.
The
captured bitumen and oleophilic solids are subsequently removed from these
surfaces,
along with some entrained water and entrained hydrophilic solids to become the
bitumen product of separation.
"bitumen" refers to a viscous hydrocarbon that contains maltenes and
asphaltenes and is found originally in oil sand ore interstitially between
sand grains.
Maltenes generally represent the liquid portion of bitumen in which
asphaltenes of
extremely small size are thought to be dissolved or dispersed. Asphaltenes
contain
the bulk of the metals of bitumen and probably give bitumen its high
viscosity. In a
typical oil sands plant, there are many different streams that may contain
bitumen that
has disengaged from the sand grains. These streams may but do not have to
contain
sand grains.
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Jan Kruyer, Thorsby, AB. Canada
"bitumen recovery" or "bitumen recovery yield" refers to the percentage of
bitumen removed from an original mixture or composition. Therefore, in a
simplified
example, a 100 kg mixture containing 45 kg of water and 40 kg of bitumen where
38
kg of bitumen out of the 40 kg is removed, the bitumen recovery or recovery
yield
would be a 95%.
"cable" refers to a non metalic rope, a metal wire rope, a single wire, a
monofilament or a multistrand filament rope.
cable wraps" refers to the wraps of endless cable wrapped around two or
more rollers where the spaces between sequential cable wraps form apertures
through
which aqueous phase can pass, giving up some or most of its bitumen content as
it
passes through the apertures.
"central location" refers to a location that is not at the periphery. In the
case
of a pipe, a central location is a location that is neither at the beginning
of the pipe nor
at the end point of the pipe and is sufficiently remote from either end to
achieve a
desired effect, e.g. washing, slurry preparation, disruption of agglomerated
materials,
heating of bitumen on cable wraps, etc.
"conditioning" in reference to mined oil sand is consistent with conventional
usage and refers to mixing a mined oil sand with water, air and caustic soda
to
produce a warm or hot slurry of oversize material, coarse sand, silt, clay and
aerated
bitumen suitable for recovering bitumen froth from said slurry by means of
froth
flotation. Such mixing can be done in a conditioning drum or tumbler or,
alternatively, the mixing can be done as it enters into a slurry pipeline
and/or while in
transport in the slurry pipeline. Conditioning aerates the bitumen for
subsequent
recovery in separation vessels by flotation. Likewise, referring to a
composition as
"conditioned" indicates that the composition has been subjected to such a
conditioning process.
"confined" refers to a state of substantial enclosure. A path of fluid may be
confined if the path is, e.g., walled or blocked on a plurality of sides, such
that there is
an inlet and an outlet, and the flow is controlled to some degree by the shape
of the
CA 02647855 2009-01-15
Jan Kruyer, Thorsby, AB. Canada
confining material, enclosure or housing. Confined path refers to a path that
is
confined by an enclosure.
"couette flow" refers to laminar flow of a viscous fluid in the space between
two or more parallel or nearly parallel surfaces, one of which is moving
relative to the
other surfaces which are stationary. The flow is driven by virtue of viscous
drag force
acting on the fluid due to the moving surface, in cooperation with or against
any
pressure gradient parallel to the surfaces. Couette flow illustrates shear-
driven fluid
motion. In the present invention the moving surface may be multiple cable
wraps and
the stationary surfaces may be the sides of a confined path enclosure.
Revolving
endless cable wraps coated with bitumen passing through a confined path may
cause
couette flow of bitumen due to the movement of the endless cable wraps
relative to
the stationary walls of the enclosure. The stationary walls may slow down the
flow of
viscous bitumen through the confined path and allow the accumulation of
viscous
bitumen to partly or completely fill a cross section of the enclosure.
"cylindrical" indicates a generally elongated shape having a circular cross-
section. Therefore, cylindrical includes cylinders, conical shapes, and
combinations
thereof. The elongated shape has a length referred herein also as a depth as
calculated
from a defined top or side wall.
"endless cable" or "endless wire rope" is used in this disclosure to refer to
a
cable having no beginning or end, but rather the beginning merges into an end
and
vice-versa, to create an endless or continuous cable. The endless cable can
be, e.g., a
wire rope, a non metallic rope, a carbon fiber rope, a single wire, compound
filament
or a monofilament which is spliced together to form a continuous loop, e.g. by
a long
splice, by several long splices, or by welding or by adhesion.
"enlarged bitumen" refers to bitumen particles that have been agglomerated in
an agomerating drum to form enlarged bitumen particles or bitumen fluid
streamers
for subsequent capture by cable wraps.
"fluid" refers to flowable matter. Fluids, as used in the present invention
typically include a liquid, gas, and/or flowable particulate solids, and may
optionally
further include amounts of solids and/or gases dispersed therein. As such,
fluid
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Jan Kruyer, Thorsby, AB. Canada
specifically includes slurries or mixtures (liquid with solid particulate),
flowable dry
solids, aerated liquids, gases, and combinations of two or more fluids. In
describing
certain embodiments, the terms sludge, slurry, mixture, mixture fluid and
fluid are
used interchangeably, unless explicitly stated to the contrary.
"long splice" refers to a splice used in the marine and in the elevator
industry
to join the ends of ropes, wire ropes or cables to increase the available
length of such
ropes or cables or to make them endless while providing good strength in the
rope or
cable at the splice. The diameter of the rope or cable at a long splice
normally is not
much larger than the average diameter of the rope or cable itself.
"metallic" refers to both metals and metalloids. Metals include those
compounds typically considered metals found within the transition metals,
alkali and
alkali earth metals. Examples of metals are Ag, Au, Cu, Al, and Fe. Metalloids
include specifically Si, B, Ge, Sb, As, and Te. Metallic materials also
include alloys
or mixtures that include metallic materials. Such alloys or mixtures may
further
include additional additives.
"multiple wrap endless cable" as used in reference to separations processing
refers to a revolvable endless cable that is wrapped around two or more drums
and/or
rollers a multitude of times to form an endless belt having spaced cables.
Proper
movement of the endless belt can be facilitated by at least two guide rollers
or guides
that prevent the cable from rolling off an edge of the drum or roller and
guide the
cable back to the opposite end of the same or other drum or roller. Apertures
of the
endless belt are formed by the slits, spaces or gaps between sequential wraps.
The
endless cable can be a single wire , a wire rope, a plastic rope, a compound
filament
or a monofilament which is spliced together to form a continuous loop, e.g. by
splicing, welding, etc. As a general guideline, the diameter of the endless
cable can be
as large as 3 cm and as small as 0.01 cm or any size in between, although
other sizes
might be suitable for some applications. Very small diameter endless cables
would
normally be used for small separation equipment and large diameter cables for
large
separating equipment. A multiwrap endless cable belt may be formed by wrapping
the endless cable multiple times around two or more rollers. The wrapping is
done in
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Jan Kruyer, Thorsby, AB. Canada
such a manner as to minimize twisting of and stresses in the individual
strands of the
endless cable. An oleophilic endless cable belt is a cable belt made from a
material
that is oleophilic under the conditions at which it operates.
"oleophilic" as used in these specifications refers to bitumen attracting.
Most
dry surfaces are bitumen attracting or can be made to be bitumen attracting. A
plastic
rope, or a metal wire rope normally is bitumen attracting and will capture
bitumen
upon contact unless the rope is coated with a bitumen repelling coating. A
plastic
rope or metal wire rope that is coated with a thin layer of bitumen normally
is
oleophilic or bitumen attracting since this layer of bitumen will capture
additional
bitumen upon contact. A plastic rope or metal wire rope will not attract
bitumen
when it is coated with light oil since the low viscosity of the light oil will
not provide
adequate stickiness for the adhesion of bitumen to the rope. Similarly, a rope
covered
with a thin layer of hot bitumen will not be very oleophilic until the thin
layer of
bitumen has cooled down sufficiently to allow bitumen adhesion to the rope
under the
conditions of the claimed methods.
"oversize solids" refers to any solids that are larger in size than the linear
distance between adjacent cable wrap surfaces and preferably refers to any
solids that
are larger than 50% of the linear distance between adjacent cable wrap
surfaces.
Such solids tend to be abrasive and may cause damage to the wraps.
"residence time" refers to the time span taken for a mixture to leave a
process,
a vessel or an apparatus after it has entered the process, vessel or
apparatus. It is
assumed that during this time span the desired separation or processing has
been
achieved.
"recovery" and "removal" of bitumen as used herein have a somewhat similar
meaning. Bitumen recovery generally refers to the recovery of bitumen from a
bitumen containing mixture and bitumen removal generally refers to the removal
of
adhering bitumen from cable wraps of an endless cable. Bitumen is recovered
from a
mixture by an oleophilic sieve when bitumen is "captured" by cable wraps in a
separation zone and adheres to the wraps. Bitumen is stripped or removed from
cable
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Jan Kruyer, Thorsby, AB. Canada
wraps in a bitumen removal zone. A bitumen recovery apparatus is an apparatus
that
recovers bitumen from a mixture.
"retained on" refers to association primarily via simple mechanical forces,
e.g. a particle lying on a gap between two or more cables. In contrast, the
term
"retained by" refers to association primarily via active adherence of one item
to
another, e.g. retaining of bitumen by an oleophilic cable. In some cases, a
material
may be both retained on and retained by cable wraps.
"roller" indicates a revolvable cylindrical member or a drum, and such terms
are used interchangeably herein.
"screen" refers to an apertured wall, sieve or cable belt. Apertures of a
wall,
of a screen or of a sieve are the holes or slits through which aqueous phase
can pass.
"sieve" refers to an apertured wall and is used interchangeably with "screen".
"single wrap endless cable" refers to an endless cable which is wrapped
around two or more cylindrical members in a single pass, i.e. contacting each
roller or
drum only once. Single wrap endless cables do not require a guide or guide
rollers to
keep them aligned on the support rollers but may need methods to provide cable
tension for each wrap when sequential cable wraps are of different lengths.
Single
wrap endless cables may serve the same purpose as multiple wrap endless cables
for
separations. When multiple wrap endless cables are specified, single wrap
endless
cables may be used in stead unless specifically excluded.
"sludge" as used herein refers to any mixture of fine solids in water and
usually contains bitumen. In describing or claiming certain embodiments, the
term
sludge and mixture are used interchangeably, unless explicitly stated to the
contrary.
In the oil sands industry, sludge is a term normally reserved for a mixture of
bitumen
and dispersed solids in a continuous water phase in a mined oil sands tailings
pond
and is sometimes referred to as "fine tails".
"slurry" as used herein refers to a mixture of solid particulates and bitumen
particulates or droplets in a continuous water phase It normally is used to
describe an
oil sand ore that has been or is in the process of being digested with water
to
disengage bitumen from sand grains.
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"sparging" or "sparged" as used herein refers to the introduction of a gas,
such as steam or other gas under pressure into bitumen or into a bitumen
containing
mixture through tubes, pipes, enclosure openings, perforated pipes or porous
pipes.
The type of gas used for sparging normally is described in the specifications.
When
steam is the sparging gas it is generally used to increase the temperature of
bitumen to
reduce its viscosity. Live steam may also serve to both heat bitumen and to
add water
to bitumen.
"substantially" refers to the complete or nearly complete extent or degree of
an action, characteristic, property, state, structure, item, or result. For
example, an
object that is "substantially" enclosed would mean that the object is either
completely
enclosed or nearly completely enclosed. The exact allowable degree of
deviation
from absolute completeness may in some cases depend on the specific context.
However, generally speaking the nearness of completion will be so as to have
the
same overall result as if absolute and total completion were obtained. The use
of
"substantially" is equally applicable when used in a negative connotation to
refer to
the complete or near complete lack of an action, characteristic, property,
state,
structure, item, or result.
"velocity" as used herein is consistent with a physics-based definition;
specifically, velocity is speed having a particular direction. As such, the
magnitude
of velocity is speed. Velocity further includes a direction. When the velocity
component is said to alter, that indicates that the bulk directional vector of
velocity
acting on an object in the fluid stream (liquid particle, solid particle,
etc.) is not
constant. Spiraling or helical flow-patterns in a conduit are specifically
defined to
have changing bulk directional velocity.
"wrapped" or "wrap" in relation to a wire, rope or cable wrapping around an
object indicates an extended amount of contact. Wrapping does not necessarily
indicate full or near-full encompassing of the object.
As used herein, a plurality of components may be presented in a common list
for convenience. However, these lists should be construed as though each
member of
the list is individually identified as a separate and unique member. Thus, no
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Jan Kruyer, Thorsby, AB. Canada
individual member of such list should be construed as a de facto equivalent of
any
other member of the same list solely based on their presentation in a common
group
without indications to the contrary.
Concentrations, amounts, volumes, and other numerical data may be
expressed or presented herein in a range format. It is to be understood that
such a
range format is used merely for convenience and brevity and thus should be
interpreted flexibly to include not only the numerical values explicitly
recited as the
limits of the range, but also to include all the individual numerical values
or sub-
ranges encompassed within that range as if each numerical value and sub-range
is
explicitly recited. As an illustration, a numerical range of "about 1 inch to
about 5
inches" should be interpreted to include not only the explicitly recited
values of about
1 inch to about 5 inches, but also include individual values and sub-ranges
within the
indicated range. Thus, included in this numerical range are individual values
such as
2, 3, and 4 and sub-ranges such as from 1-3, from 2-4, and from 3-5, etc. This
same
principle applies to ranges reciting only one approximate numerical value.
Furthermore, such an interpretation should apply regardless of the breadth of
the
range or the characteristics being described.
Bold headings in the present disclosure are provided for convenience only.
OIL SAND SLURRIES
Oil sand slurries are produced from mined oil sand ores by mixing water with
oil sand ore and thoroughly agitating this mixture. In the Clark process this
is called
"conditioning" which refers to the addition of hot water and caustic soda to
the ore to
disengage bitumen droplets from the sand grains, as the mixture is tumbled in
a drum
and captures and disperses air to form aerated slurry. The slurry is next
flooded with
warm water and then is separated by froth flotation. Alternately a cyclo-
feeder is
used to introduce oil sand and water into a slurry pipeline where the ore,
mixed with
warm water and caustic soda in a vortex also traps air. The mixture then flows
through the pipeline to further "condition" the slurry by turbulent vortices,
after
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Jan Kruyer, Thorsby, AB. Canada
which the slurry is separated into bitumen froth and tailings by the Clark
process. Air
can also be added to the slurry along the pipeline to encourage the adhesion
of
bitumen droplets to air bubbles for ease of subsequent froth flotation. When a
conditioning drum is used, oversize material is removed from the drum before
the
slurry is sent to bitumen extraction in the Clark process. When a cyclo-feeder
is used,
the oil sand ore is first crushed before it enters the cyclo-feeder and slurry
pipeline,
and may also be screened before it enters the pipeline.
In the Kruyer process, slurry preparation is carried out in a different
procedure. Bitumen may be disengaged from the oil sand ore in a tumbler by
mixing
warm water with oil sand ore followed by oversize removal before capture and
recovery of bitumen. Major differences are that caustic soda is used more
sparingly
or not at all for commercial grade oil sand ore, the water content of the
slurry in the
drum usually is higher and none or less air is mixed in with the slurry. This
results in
almost no air being trapped in the slurry leaving the tumbler. The reduction
or
elimination of supplied air results in a bitumen product of the subsequent
separation
by an oleophilic apertured wall that is not froth but is a free flowing
liquid.
In the Kruyer process, slurry preparation may also be done without the use of
a drum. In that case, crushed oil sand ore is mixed with warm water and is
introduced
into a pipeline. Part of this pipeline may consist of a serpentine pipe. Such
a
serpentine pipe is disclosed in co-pending patent application entitled
"Sinusoidal
Mixing and Shearing Apparatus and Associated Methods". In the serpentine pipe
the
solids of the slurry rapidly swing back and forth through the flowing liquid
of the
slurry and impact the pipe wall repeatedly, causing a thorough mixing of the
slurry
and the breaking up of undigested oil sand ore. The digested slurry is then
passed
through a hydrocyclone that uses a confined helical path in the form of a pipe
coil or
pipe spiral in advance of the main hydrocyclone vessel. From this vessel,
coarse sand
and larger oversize mixed with water leaves through the underflow to disposal
and
fine particulates and bitumen suspended in water leave through the overflow to
bitumen extraction by an oleophilic screen or sieve. Small amounts of water
and/or
gas may be introduced into the coarse solids stream by jets along the outer
wall of the
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Jan Kruyer, Thorsby, AB. Canada
curving confined path to encourage bitumen to migrate out of the coarse
particulates
to subsequently report to the overflow. The resulting overflow is low in
coarse solids
and is readily separated by a sieve formed by oleophilic wraps of an endless
cable. A
detailed description of the hydrocyclone is provided in co-pending patent
application
entitled "Hydrocyclone and Associated Methods". The oleophilic apertured belt
and
its operation are described in detail in co-pending patent application
entitled "Endless
Cable System and Associated Methods". Normally the mixture temperature for
separation does not exceed 70 degrees centigrade and often the mixture
separation is
carried out at temperatures below 40 degrees centigrade. If a very low
separation
temperature is desired, well below 30 degrees centigrade, a hydrocarbon
diluent may
be added to the oil sand ore in small quantities to reduce the viscosity of
bitumen in
the slurry to aid in the disengagement of bitumen from the sand grains as the
ore
flows in the drum or in the pipeline. This diluent may be one or more of the
group
consisting of natural gas condensate, propane, butane, pentane, other alkane,
diesel
fuel, kerosene, jet fuel or naphtha.
Removal of bitumen from the wraps of an endless cable may be done by
squeeze rollers, scrapers or combs at the separating mixture temperature, or
bitumen
removal may be done at elevated temperatures through heating the captured
bitumen
after leaving the separation zone(s) while still on the cable wraps. Such
heating is
described in detail with Figures 7 and 8.
MORE DETAILED DESCRIPTION OF THE FIGURES
FIG. I a is an isometric drawing of an endless wire rope screen described in
the above
referenced co-pending patent application entitled: "Endless Cable System and
Associated Methods". It shows two rollers, supported in bearings, covered by a
multitude of wraps of an endless cable to form an apertured screen or sieve
without
cross members. The screen apertures are formed by the spaces between the
wraps. A
guide or two guide rollers direct the last wrap and cause it to flow
seamlessly into the
first wrap to prevent the cable from revolving off the rollers. The bottom
right one of
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Jan Kruyer, Thorsby, AB. Canada
the two rollers is provided with a drive to revolve the screen. The screen of
this and
succeeding Figures may contain sufficient wraps to achieve the desired
objective of
separation of a mixture. Normally the number of wraps will exceed 10 and may
amount to many hundreds of wraps depending on the desired apparatus design.
FIG. 2 represent schematic drawings of endless cable belt screens or sieves
for
bitumen capture and removal that use both a sloping top flight and a sloping
bottom
flight. FIG. 2a uses 6 separation zones and six bitumen removal zones. The
cable
belt is sloping to take advantage of the difference in viscosity between
bitumen and
water and also to take advantage of adhesion of bitumen to oleophilic cable
wrap
surfaces and the general lack of adhesion of aqueous phase of a mixture to
such cable
wrap surfaces. Mixture to be separated flows from containers 210, 220, 230,
240,
250 and 260 above the separation zones 211, 221, 231, 241, 251 and 261 of the
screen 200 moving in the direction shown by the arrow 201. Tailings of the
separation, containing water, particulate solids and a small amount of bitumen
flow
into the tailings receptacles 212, 222, 232, 242, 252, and 262. The screen is
supported by support rollers 213, 223, 233, 243, 253, and 263 and squeeze
rollers
214, 224, 234, 244, 254, and 264 that press against these support rollers. At
every
separation zone, bitumen is captured by the surfaces of the belt 200 cable
wraps and
is conveyed upward to encounter a support roller and a squeeze roller, which
squeeze
the captured bitumen from the cable wraps into bitumen receivers 215, 225,
235, 245,
255, and 265. Water and hydrophilic particulate solids generally do not adhere
to
oleophilic cable wraps but flow downward over the screen, or at least move at
a lower
velocity than the screen 200 in each separation zone until this aqueous phase
encounters open apertures that allow it to flow through the open apertures
between
the cable wraps into the tailings receivers. Since separation is never
perfect, the
bitumen product removed from the wraps, and collecting in the bitumen
receivers,
will contain some water and hydrophilic solids. Similarly, the aqueous phase
tailings
will contain some residual amount of bitumen. Hence, placing the cable screen
at an
angle, as shown in FIG. 2a results in more effective separation of the bitumen
phase
from the aqueous phase. Bitumen phase captured by the cable wraps moves at
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Jan Kruyer, Thorsby, AB. Canada
essentially the same velocity as the cable wraps, whereas aqueous phase tends
to flow
along the cable wraps at a slower velocity than the wraps, or in some cases in
a
direction opposite to the direction of movement of the wraps, depending on the
slope
of the belt in the separation zone. Complete blinding of the screen by bitumen
is
thereby eliminated. The resulting bitumen product contains a lower amount of
carry-
over of aqueous phase, since aqueous phase can rapidly move through the spaces
between cable wraps not filled with captured bitumen instead of being carried
for
some distance on top of bitumen conveyed by cable wraps. The angle of incline
of
the cable wrap screen in separation zones may be selected for optimum
separation
and will be determined by the type of mixture to be separated, the velocity of
the
endless screen and the flow rate of mixture to be separated. The high
viscosity
bitumen captured by wraps of the endless screen is not affected much by the
downward pull of gravity and moves upward at about the same velocity as the
screen.
However, the aqueous phase has a much lower viscosity and will tend to flow
slower
or against the movement of the screen if the angle of incline, or slope, of
the wire
rope screen in the separation zones is steep enough. A suitable angle of
positive
incline of the screen may be between 3 and 45 degrees or between 5 and 15
degrees
depending upon the type of mixture to be separated and the desired equipment
design.
An additional support roller 202 is used for FIG. 2a to allow both the top
flight and
the bottom flight to be inclined in the direction of screen movement. Both top
flight
and bottom flight contain separation zones and bitumen removal zones. In this
Figure
the screen formed by the wraps of the endless cable would normally show, in
end
view, as a solid line supported by drum and rollers, but here it is shown as a
thick
dashed line to convey the concept that the screen, while formed from wraps of
a cable
is apertured since the spaces between the wraps are the apertures.
FIG. 2b is a schematic drawing of an endless cable belt with sloping top
flight
and sloping bottom flight for bitumen capture and removal using 2 separation
zones
(bitumen capture zones) and 2 bitumen removal zones wherein the mixture to be
separated is provided from a distributor along the top flight and from a
distributor
along the bottom flight. The endless cable belt has a top flight 266 and a
bottom flight
CA 02647855 2009-01-15
Jan Kruyer, Thorsby, AB. Canada
267 and is supported by three support rollers 268, 269 and 270 while two
squeeze
rollers 271 and 272 serve to remove bitumen from the endless cable wraps.
Roller
269 is used to achieve a positive incline for both the top flight and the
bottom flight.
Bitumen product removed from the top flight flows into collection vessel 273
and
bitumen product removed from the bottom flight flows into collection vessel
274.
Direction of movement of the endless cable belt is shown by arrows on the top
flight
266 and on the bottom flight 267. The mixture 275 to be separated by the top
flight
flows into a distributor 276 with an apertured bottom, which distributes the
mixture
over the width of the endless cable belt. Bitumen captured by the top flight
adheres
to cable wraps and is removed by two rollers 268 and 271 or may be removed by
other means, such as by combs or scrapers as described in co-pending patent
application "Endless Cable System and Associated Methods". Tailings 277 from
the
top flight, having passed through the spaces between the cable wraps of the
top flight
266 flow into a tailings receptacle 278 and are removed therefrom. A similar
separation takes place along the bottom flight. Mixture 279 to be separated
flows into
a distributor 280 which distributes it over the width of the bottom flight 267
for the
capture of bitumen from this mixture by cable wraps of the bottom flight.
Tailings
283 having passed through the spaces between cable wraps of the bottom flight
267
are collected in a receiver or are directed by a baffle 284 to become the
final tailings
285 of separation from the bottom flight. The bitumen captured from this
mixture by
the wraps of the bottom flight is removed by two rollers 270 and 272 or by
other
means described in the co-pending patent application referenced above. Jets of
water
281 may be used to wash superficial solids from the captured bitumen and jets
or
currents of air 282 may be used to remove superficial water from the captured
bitumen adhering to the cable wraps. Guide rollers are shown above roller 268
to
illustrate that the last wrap of the endless cable flows seamlessly into the
first wrap to
keep the endless cable on the support rollers. For simplicity these guide
rollers are
not shown in FIG. 2c, which is an isometric drawing of small size of some
elements
of FIG. 2b
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Jan Kruyer, Thorsby, AB. Canada
The slope or incline of a flight may vary depending on the mixture to be
separated, on mixture temperature and on the desired separator design. It may
be
between 3 degrees and 45 degrees or may preferably be between 5 and 15 degrees
upward in the direction of flight movement.
FIG. 2c is an isometric drawing of the rollers and of the endless cable belt
of
FIG. 2b. This drawing is provided to illustrate what the bare equipment
elements of
FIG. 2b would look like in perspective view.
FIG. 2d is similar to FIG. 2b in providing 2 separation zones and 2 bitumen
removal zones, but in this case the initial tailings from the top flight flow
into an
agglomerator 291 wherein residual bitumen particles of the initial tailings
are
increased in size before flowing to the bottom flight for capture by the
endless cable
belt along the bottom flight. Alternately a distributor may be used along the
bottom
flight similar to the distributor 294 of the top flight, instead of an
agglomerator 291 to
provide two stage separation without agglomeration. FIG. 2d is similar to FIG.
2b in
providing 2 separation zones and 2 bitumen removal zones but in the case of
FIG. 2d
the device has become a two stage separator in which tailings from the top
flight
become feed for separation by the bottom flight by flowing into an
agglomerator
wherein residual bitumen particles of these initial tailings, not captured by
the top
flight, are increased in size before flowing to the bottom flight for capture
by the
wraps of the endless cable belt along the bottom flight, resulting in final
tailings that
have passed through apertures of the bottom flight. Two support rollers 286
and 287
are provided, as well as two squeeze rollers 289 and 290. The left bottom
roller (269
of FIG. 2b) is replaced by an agglomerator drum 291, which has an apertured
cylindrical wall 292. For this two stage separator, the mixture 293 to be
separated
flows into a distributor 294 and from there passes to the top flight 295 where
bitumen
is captured by cable wraps as initial tailings flow through the spaces between
the
wraps. These initial tailings 296 are directed by a baffle 297 and flow into
the
agglomerator 291 through the apertured agglomerator wall 292 to contact
oleophilic
balls 298 or oleophilic tower packings to increase the particle size of the
residual
bitumen particles in these tailings and then flow to the bottom flight for
capture of
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Jan Kruyer, Thorsby, AB. Canada
residual bitumen by wraps of the bottom flight while the mixture passes
through the
spaces between cable wraps of the bottom flight to become the final tailings
product
299 of separation.
There are many designs possible for using oleophilic cable wraps to achieve
separation. In some cases the top flight may be inclined and the bottom flight
may be
wrapped around approximately half the cylindrical wall of an apertured
agglomerator.
FIG. 3a is a schematic drawing of an endless cable belt for bitumen removal
using a
sloping top flight 313 for bitumen capture and removal, and a bottom flight
328
supported by an agglomerator 319 for bitumen particle enlargement and
subsequent
capture and removal. Similar to FIG. 2a, b and d, the screen formed by wraps
of the
endless cable is shown in FIG. 3 as a thick dashed line to convey the concept
that the
screen, while formed from cable wraps is apertured since apertures are
provided by
the spaces between sequential wraps. Similar to FIG. 2d, the top flight of the
screen is
inclined but, in this case, the bottom flight is wrapped for about 180 degrees
around
an agglomerator drum 319 filled with a bed 321 of steel and/or plastic balls
that
tumble inside the drum 319. The agglomerator drum increases the particle size
of
bitumen particles in initial tailings not captured by the top flight. The drum
causes
enlarged bitumen particles to be captured by the bottom flight 328 before
final
tailings are removed from the process. The balls are oleophilic and capture
and hold
bitumen for a while, kneed the bitumen due to the ball movement and thereby
may
remove some of the water and solids trapped in the bitumen particles. In some
cases,
the agglomeration process may actually increase the solids content of the
captured
bitumen. This seems to be a function of the chemistry of the mixture, the type
of
solids and the ions present in the mixture. (A similar process takes place in
the
agglomerator of FIG. 2d). In FIG. 3a, initial tailings 317 from the top flight
enter the
drum 319 through apertures 314 of the cylindrical wall 301, mix with balls to
give up
bitumen to the balls and then percolate through the bitumen covered bed 321 of
balls
or flow over top of the bed of balls to become the final tailings 322 which
pass
through drum and belt apertures 327 and flow into a tailings receiver 329 for
removal
by removal means 324. Aqueous phase 320 in part flows over the bed of balls
since
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Jan Kruyer, Thorsby, AB. Canada
rotation of the drum causes the bed 321 of balls to assume a top surface that
is
inclined upward in the direction of rotation. Captured bitumen is sloughed off
the
balls due to drum rotation and shear inside the drum and flows to the
apertured drum
wall 328 in the right bottom quadrant of the Figure. There the endless cable
screen
apertures are partly or completely filled with collecting bitumen and this
reduces or
prevents the passage of aqueous phase to and through the cable wraps in that
quadrant. Aqueous phase 322 flows more readily through the apertures of the
cable
wrap screen at the left bottom quadrant of the drum since the revolving wire
rope
screen provides open apertures in that quadrant. Apertures in the drum wall
normally
are much larger than apertures in the wire rope screen to assure that blinding
of the
drum apertures does not occur. Since the apertures of the wire rope screen are
much
smaller in at least one dimension than the apertures of the drum wall, most of
the
bitumen residing in drum apertures adjacent to bitumen filled screen apertures
goes
with the screen as the screen pulls away from the drum wall due to the
continuous
rotation of the drum. Hence, as a result of rotation, after leaving the
screen, the drum
apertures normally are open apertures not blinded with bitumen. Along the
bottom
right drum quadrant, cable wrap apertures are partly or completely filled with
bitumen and this reduces or prevents the flow of aqueous phase through the
drum
apertures in that quadrant.
Thus, along the top flight the aqueous phase can flow down the incline of the
upward moving screen until it finds open apertures of the screen through which
it can
pass and along the bottom flight of the screen the aqueous phase can flow down
the
inclined of a bed of revolving balls to find open apertures of the screen
through which
it can pass. The aqueous phase initial tailings leaving the top flight flow
into the
drum that supports the bottom flight. A large portion of this aqueous phase
falls on
top of the bed of balls and releases residual bitumen to the balls of that bed
and then
flows down the incline of the revolving bed to open apertures of the bottom
flight of
the screen. All this occurs because bitumen adheres strongly to oleophilic
surfaces
and moves slowly due to its high viscosity whilst aqueous phase does not
adhere
readily to oleophilic surfaces and can flow rapidly down an incline because of
its
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Jan Kruyer, Thorsby, AB. Canada
relatively low viscosity. Hence, the incline of the screen and the incline of
the bed of
balls in the separation zones both take advantage of the differences in
viscosity and of
the differences of adhesion properties of the components in the separating
mixture for
oleophilic surfaces, or for bitumen adhering to oleophilic surfaces, to
achieve rapid
mixture separation. Of coarse the inclined belt flight portion of the top
flight must be
inclined upward in the direction of endless cable screen movement to effect
this
improved separation. Similarly, the bed of balls must have an upper surface
that is
inclined upward in the direction of screen movement. However, this is the
natural
position assumed by a bed of balls in a revolving drum.
A strong drum is required when the bed of balls is large and heavy. This is
accomplished by using a heavy wall pipe as the core 302 of the drum that is
attached
to the drum shaft 303. Additional drum construction details are provided in
subsequent Figures to provide for strong drums that can support beds of balls.
In
addition to the agglomerator drum 319 of FIG. 3a, four additional rollers are
used to
support and guide the endless cable screen. The arrows 308 and 309 show the
direction of screen movement. The support roller 304 and the squeeze roller
310
remove captured bitumen from the bottom flight and deposit it into a product
receiver
325. A baffle guide 326 directs this product into the receiver and prevents it
from
falling past the receiver. In the case of rollers 304, 310, the shafts
normally are
horizontal but the rollers do not have to be in horizontal alignment with each
other
but can be in sloping alignment, as shown by the line 307. This may be done to
facilitate bitumen flow into the receiver 325 from the revolving cable wrap
screen
without spillage. The support roller 305 and the squeeze roller 306 remove
captured
bitumen from the top flight and deposit it into a product receiver 316. A
guide or
guide rollers 318 keep revolving multi wrap endless cable on the rollers and
on the
drum if used in stead of single wrap cables. A water wash 334 may be used
along the
top flight to wash solids off the bitumen captured by the top flight and air
315 may be
blown onto the top flight to dry the captured bitumen.
Thus in summary, mixture to be separated 311 flows into a dispenser 312 that
distributes the mixture over the width of the inclined top flight. Bitumen is
captured
CA 02647855 2009-01-15
Jan Kruyer, Thorsby, AB. Canada
by oleophilic wraps of the top flight 313, moves upward with the cable wraps
and
then is removed by rollers or by other means disclosed in co-pending patent
application entitled "Endless Cable System and Associated Methods". The
aqueous
phase of the mixture flows along the inclined top flight with or against the
movement
of the wraps until it finds open apertures in the top flight 313 and flows
through them.
These initial tailings then fall on top of the apertured drum 301 wall, pass
through the
apertures 314 of the cylindrical drum wall and contact the bed of balls 321.
There
residual bitumen particles from these tailings 317 are agglomerated by
revolving balls
of the bed 321 to form enlarged bitumen particles. These are then captured by
the
oleophilic wraps of the bottom flight 328 and the now more bitumen depleted
aqueous phase becomes the final tailings product 322. This product flows out
of the
drum through the open apertures 327 of the bottom flight and is collected in a
vessel
329 to become the final tailings product 324 of the process.
A single apparatus has thus been developed to achieve two stages of rapid
bitumen extraction from an aqueous mixture containing bitumen. Operation of
such a
two stage process may vary but contains some similar features. Bitumen is
recovered
from a mixture by the top flight, leaving aqueous initial tailings to flow
into a drum
for the removal of additional bitumen by the bottom flight. After that the
final
tailings product, representing bitumen depleted or bitumen reduced aqueous
phase,
flows into a tailings receiver or baffle to be removed from the process. All
initial
tailings from the top flight are thus agglomerated and processed along the
bottom
flight to remove additional bitumen, and yield a final tailings product that
is sent to
disposal or further processing. For example, after settling or removal of
sand, the
final tailings may be processed by electrophoresis to separated these tailings
into
clarified water and dewatered solid fines as described in co-pending patent
application entitled "Electrophoresis of Tailings Suspension using Endless
Cable
Wraps"
A bed of tumbling balls is illustrated in FIG. 3a, and this bed 321 only fills
part of the drum interior. The drum 319 may alternately be filled with
oleophilic
tower packings. Such tower packings are conventionally used in packed
distillation
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Jan Kruyer, Thorsby, AB. Canada
towers or are used in conventional extraction towers. Plastic tower packings
are light
and tend to adhere to each other by captured bitumen and have a very large
open area
for fluid flow. These packings normally do not tumble in a revolving drum
agglomerator because of bitumen adhesion. For that reason the drum is filled
completely or nearly completely with these packings. The packings revolve in
unison
with the drum wall and do not tumble. Bitumen agglomeration then takes place
as the
initial tailings from the top flight 317 pass by the widely spaced oleophilic
surfaces of
the packings inside the revolving drum. Oleophilic tower packings are much
lighter
than a bed of balls that must be heavy enough tumble in the presence of
bitumen of
high viscosity to effect the aglomeration. Unlike tower packings, these balls
do not
have widely spaced oleophilic surfaces through which the aqueous phase can
flow but
must tumble and be in constant movement to contact the aqueous phase. Tower
packings, therefore provide another convenient method for bitumen
agglomeration in
a revolving drum. A drum using light polypropylene tower packings, does not
have to
be as strong as a drum using a bed of heavy balls. However, a bed of balls
will tend
to kneed the collected bitumen inside a bed of balls and this does not occur
when
tower packings are used. Under some conditions kneeding is preferred, in other
conditions it is not. Kneeding of bitumen of some mixtures may capture solids
in the
bitumen product. In other cases, kneeding of bitumen from mixtures may release
solids from the bitumen product. This difference is largely dependent upon the
chemical make up of the mixture and can be determined by agglomeration
experiment.
FIG 3b is an isometric drawing of endless cable wraps and of three support
rollers of FIG. 3a. The three support rollers consist of two grooved rollers
351 and
361 and one apertured drum 355 provided with notched bars 371 to keep the
wraps
353 and 360 in spaced parallel alignment along part of the cylindrical surface
367 of
the drum 355. The wraps 360 connect the drum 355 cylindrical surface 367 with
the
support roller 361, which roller forms part of the bitumen removal zone of the
top
flight 352. The squeeze roller 306 of FIG. 3a is not shown here for the sake
of
simplicity of drawing FIG. 3b. The wraps 353 connect the drum 355 cylindrical
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Jan Kruyer, Thorsby, AB. Canada
surface 367 with the support roller 351, which roller forms part of the
bitumen
removal zone of the bottom flight. The squeeze roller 310 of FIG. 3a is not
shown
here for the sake of simplicity of drawing FIG. 3b. The two support rollers
have
grooves 370 and are provided with shafts 350 and 362 which are mounted in
bearings
(not shown). Similarly, drum 355 is provided with end shafts 354 and 359 that
support a central pipe core 358. Pipe end 366 attaches to shaft end 359 and
drum end
356 attaches to drum apertured wall 367 and to pipe end 358. Such attachments
normally are by welding. The same attachments are provided to shaft end 354.
The
drum 355 also is provided with notched bars 371 that keep the wraps in
parallel
alignment along part of the drum cylindrical wall 367. The end walls 356 of
the drum
355 are not apertured but the cylindrical wall 367 of the drum 355 is provided
with
apertures 357. Guide rollers 363 and 364 direct the endless cable 365 to allow
the
last wrap to flow seamlessly into the first wrap to prevent the endless cable
365 from
running off the grooved rollers 351 and 361 and drum 355. The top flight 352
is
inclined and the direction of wrap movement is from roller 351 upwards and to
the
left towards roller 361. From there the movement of the revolving wraps is
downward from roller 361 towards drum 355. Guide roller 363 guides the last
wrap
towards guide roller 364, which guides this last wrap to seamlessly become the
first
wrap returning to the drum 355. The guided wrap 365 may contact the surface of
roller 361 at the first and at the last groove, but does not have to contact
the surface of
this roller to achieve proper wrap guidance on the circumferences of the
rollers and
drum. Contact with roller 361 of the first and last wrap is simply a function
of the
placement of the guide rollers 363 and 361. This Figure illustrates the wraps
of only
one endless oleophilic cable. Several such endless cables may be mounted on
rollers
351, 361 and drum 355 if that is convenient. In that case, each endless cable
will
need a set of guide rollers to keep the wraps in proper aligment. Only when
single
wrap endless cables are used for the endless screen will guide rollers not be
required.
In that case a mechanism for providing the required tension in each single
wrap
endless cable may need to be provided if the single wraps are not identical or
not
nearly identical in length.
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FIG. 4 provides details for the construction of an agglomerator and for roller
support. FIG. 4, 5 and 6 all illustrate construction details that are
beneficial for the
design of effective equipment for bitumen extraction using endless oleophilic
cable
wrap screens in which the bottom flight of the screen is wrapped around part
of an
apertured drum.
FIG. 4a is an isometric drawing of one type of central core support for an
apertured agglomerator drum, using a heavy wall pipe 401 to provide the
required
core strength. The shaft ends 402 are mounted in bearings 406 and are welded
to pipe
end disks 404 which in turn are welded to the ends of the pipe 401 to provide
a very
strong and rigid central core for the drum. Ring flanges 413 are welded to the
pipe
401 outside diameter to allow for the attachment of supporting ribs, baffles
or tie bars
that tie the central core to the apertured cylindrical drum wall shown in FIG
4b. A
sprocket 403 mounted to the shaft 402 may be used to drive the drum, or a gear
or
gear box may be used, coupled to a motor.
FIG. 4b is a typical cross sectional drawing of the internals of an
agglomerator
drum. Shaft ends 402 are welded to the end discs 406 of the central pipe 401.
Support baffles or tie bars 410 tie the apertured drum wall 412 to the central
pipe 401
by means of ring flanges 413 that were welded to the pipe 401 outside surface.
The
baffles 410 or tie bars are welded to or connected to cross bars 411 which
cross bars
are parallel with the pipe axis, and support the apertured drum wall 412 which
may be
made from thick plates of perforated steel rolled into the form of a cylinder
or rolled
into sections of a cylinder.
FIG. 4c is an internal view of an agglomerator drum through section A-A of
FIG. 4b. The drum has a central core 432 and a perforated steel cylindrical
wall 430
supported by cross bars 431. For the sake of simplicity of the drawing, the
support tie
bars or baffles between pipe core and drum wall are not shown. The drum is
partly
filled with metal and optional plastic balls to form a bed 434 for the
agglomeration of
bitumen. The average slope of the bed 434 of tumbling balls is consistent in
sloping
upward in the direction of drum movement shown with the arrow 436.
34
CA 02647855 2009-01-15
Jan Kruyer, Thorsby, AB. Canada
FIG. 4d is an internal view of an agglomerator drum through section A-A of
FIG. 4b completely filled with oleophilic tower packings. The central core
assembly
424 consists of a shaft and pipe core. Shown also are the tie bars 423 or
baffles that
connect the ring flanges (413 of FIG. 4a and 4b) to the cross bars 421 of the
apertured
drum wall 422. This apertured drum wall may be made from sections of rolled
perforated or drilled steel plates. Alternately the apertured drum wall may
not need
rolled apertured steel plates but may consist of a large number of cross bars
that are
welded to baffles (410 of FIG. 4b) and/or which may be welded to the endwalls
(404
of FIG. 4b) to form an apertured cylindrical drum wall. In this case the cross
bars are
notched to accept the cable wraps and keep the wraps in alignment.
FIG. 4e, at the top of the page, is a detail showing the brackets that may be
used to support two rollers; one roller to support the endless cable belt and
the other
roller to squeeze against the support roller to remove bitumen from the
screen. This
bracket 441 contains a fixed pillow block 442 with bearings for the support
roller
shaft and an adjustable pillow block 444 with bearings for the squeeze roller
shaft.
This pillow block 444 is mounted in a slide 445. A threaded rod 447 with nuts
is
used to adjust the position of this pillow block to exert the desired pressure
between
support roller and squeeze roller on bitumen adhering to the wraps. Two such
brackets are required to support the two ends of the roller shafts, and these
two
brackets are attached to each other to form a bearing unit by means of bars or
threaded rods to keep the roller shafts properly supported. The resulting
mounted
roller bearing unit assembly can be attached to the structural parts of a
separator by
means of bolts through mounting holes 443 in each bracket. The mounting holes
443
are located to be close to pinch point 450 between the two rollers in the
assembly and
this allows for convenient angular rotation of the assembly to position the
roller axes
alignment not necessary perpendicular to the screen but at an angle. This
angle is
shown by the line 307 in FIG. 3 and facilitates the removal of bitumen from
the
bottom flight 328 of that Figure. As a result of this mounting, the squeeze
roller 310
can be located in horizontal alignment with the support roller 304, or it can
be located
further along the endless screen in the direction 309 of belt movement if so
desired
CA 02647855 2009-01-15
Jan Kruyer, Thorsby, AB. Canada
for more effective flow of removed bitumen product into the bitumen receiver
325
without spillage. The assembly is mounted with bolts through the mounting
holes
443 of FIG. 4e and the rotated position may be fixed with a bracket or with
brackets
(not shown) attached between the bearing unit assembly and the separator
structural
parts. An end view 446 of the assembly is shown as well in FIG. 4e.
FIG. 5 provides additional details for the construction of an agglomerator
drum.
FIG. 5a is an isometric drawing of an agglomerator drum, showing central
shaft ends 503, central pipe 502 and a perforated cylindrical drum wall 505.
It also
shows an unperforated drum end wall 504 and also the location of notched bars
501
mounted in the cylindrical drum wall 505 that are intended to keep the wraps
of the
endless cable screen in spaced alignment around at least part of the
cylindrical drum
wall.
FIG. 5b is an internal view of an agglomerator showing shaft 513, support
pipe core 516, support pipe end wall or disc 514, support brackets or baffles
512, and
an apertured drum wall 511. It also shows the location of notched bars 518
that keep
cable wraps in proper alignment along part of the apertured cylindrical drum
wall
511, and brackets 517 that attach notched bars 518 to the baffles 512 and to
the
perforated steel drum wall 511. As shown in this Figure, the baffles 512
provide rigid
support between the central core 514 and the aglomerator cylindrical apertured
wall
511. These baffles may be cut as complete units from steel plates or each may
be
fabricated by welding support bars between two rings; one ring being a ring
flange
413 of FIG. 4b and the other may be a rolled steel ring on edge to have an OD
of the
same size as the ID of the perforated steel drum wall 511.
FIG. 5c is an enlarged detail drawing of a section 527 of the apertured
agglomerator drum wall showing the mounting of notched bars 528 into the drum
wall. Mounting brackets 522 are attached to or welded to the baffles 529 and
are
provided with bolt holes for bolting notched bars 528 into the cylindrical
drum wall.
The mounting brackets 522 can be cross bars that are welded to the baffles
529.
Additional cross bars 540 may be welded to the baffles and to the apertured
drum
36
CA 02647855 2009-01-15
Jan Kruyer, Thorsby, AB. Canada
wall to provide rigidity and strength to the circumferential drum wall (511 of
FIG.
5b). The notched bars 528 keep the wraps of the endless cable in alignment
along
part of the perforated circumferential drum wall. This drum wall is
constructed by
welding rolled perforated steel sections 527 to the baffles 529 between the
notched
bars 528. Altermately, perforated steel sections are not required when a large
number
of notched bars 528 are welded to the baffles instead, replacing the un-
notched cross
bars 540 and eliminating the apertured steel plates. In any case, proper
alignment of
notches of the notched bars is very important to keep the wraps of the endless
cable
properly aligned along at least part of the circumferential drum wall. In FIG.
5b and
5c the notched bars are bolted to the baffles to allow replacement of the
notched bars
when the notches wear out due to extended moving contact between the notched
bars
and the endless cable wraps in an abrasive environment. If no such wear is
experienced, for example when separating tailings pond sludge, the notched
bars may
be welded to the cylindrical wall instead.
FIG. 5d is a detail drawing of a typical notched bar. The bar is provided with
mounting holes 531 for attachment to the mounting brackets (522 of FIG. 5c)
and
with ends 532 that fit between the end walls (504 of FIG. 5a) of the
agglomerator
drum. Each bar may be milled or may more conveniently be cut with a laser beam
or
a jet of abrasive water to provide notches 533 that match the OD of the
endless cable
and to provide protrusions 534 that keep the wraps in alignment.
FIG. 5e is an alternate design of a notched bar, showing the mounting holes
and notches 533 and protrusions 534 to properly align the wraps. The notches
may
have contoured bottoms to accept the wraps with minimal deformation of the
cable
circumference. Alternately, wear by the wraps will contour the notch bottoms
while
the bars are in use.
FIG. 6 is a drawing of a two stage separator using two agglomerator drums,
one of which includes an optional apertured internal cylindrical wall 614 for
the
removal of oversize material prior to bitumen agglomeration. FIG. 6 is
included to
show the versatility of endless cable wraps around drums and rollers to form
apertured screens. These cables may be less than a millimeters in diameter or
smaller
37
