Note: Descriptions are shown in the official language in which they were submitted.
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ENDLESS CABLE SYSTEM AND ASSOCIATED METHODS
RELATED APPLICATIONS
This application claims priority to U.S. Patent Application No. 11/948,816,
filed
November 30, 2007.
This application is related to U.S. Patent Application Nos. 11/939,978
entitled
"Sinusoidal Mixing and Shearing Apparatus and Associated Methods," filed
November 14,2007
(hereinafter referred to as "Sinusoidal Mixing Application") and 11/940,099
entitled
"Hydrocyclone and Associated Methods," filed November 14, 2007 (hereinafter
referred to as
"Hydrocyclone Application"), and 11/948,851 entitled "Isoelectric Separation
of Oil Sands"
filed November 30, 2007 (hereinafter referred to as "Isoelectric
Application").
FIELD OF THE INVENTION
The present invention relates to devices and methods for separating materials.
Accordingly, the present invention involves the fields of materials science,
chemistry, and
chemical engineering.
BACKGROUND OF THE INVENTION
According to some estimates, oil sands, also known as tar sands or bituminous
sands,
may represent up to two-thirds of the world's petroleum. Oil sands resources
are relatively
untapped. Perhaps the largest reason for this is the difficulty of extracting
bitumen from the
sands. Mineable oil sand is found as an ore in the Fort McMurray region of
Alberta, Canada,
and elsewhere. This oil sand includes sand grains having viscous bitumen
trapped between the
grains. The bitumen can be liberated from the sand grains by slurrying the as-
mined oil sand in
water so that the bitumen flecks move into the aqueous phase for separation.
For the past 40
years, bitumen in McMurray oil sand has been conunercially recovered using the
original Clark
Hot Water Extraction process, along with a number of improvements. Karl Clark
invented the
original process at the University of Alberta and at the Alberta Research
Council around 1930
and improved it for over 30 years before it was commercialized.
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In general terms, the conventional hot water process involves mining oil sands
by bucket
wheel excavators or by draglines at a remote mine site. The mined oil sands
are then conveyed,
via conveyor belts, to a centrally located bitumen extraction plant. In some
cases, the
conveyance can be as long as several kilometers. Once at the bitumen
extraction plant, the
conveyed oil sands are conditioned. The conditioning process includes placing
the oil sands in a
conditioning tumbler along with steam, water, and caustic soda in an effort to
disengage bitumen
from the sand grains of the mined oil sands. Further, conditioning is intended
to remove
oversize material for later disposal. Conditioning forms a hot, aerated slurry
for subsequent
separation. The slurry can be diluted for additional processing, using hot
water. The diluted
slurry is then pumped into a primary separation vessel (PSV). The diluted hot
slurry is then
separated by flotation in the PSV. Separation produces three components: an
aerated bitumen
froth which rises to the top of the PSV; primary tailings, including water,
sand, silt, and some
residual bitumen, which settles to the bottom of the PSV; and a middlings
stream of water,
suspended clay, and suspended bitumen. The bitumen froth can be skimmed off as
the primary
bitumen product. The middlings stream can be pumped from the middle of the PSV
to sub-
aeration flotation cells to recover additional aerated bitumen froth, known as
a secondary
bitumen product. The primary tailings from the PSV, along with secondary
tailings product
from flotation cells are pumped to a tailings pond, usually adjacent to the
extraction plant, for
impounding. The tailings sand can be used to build dykes around the pond and
to allow silt,
clay, and residual bitumen to settle for a decade or more, thus forming non-
compacting sludge
layers at the bottom of the pond. Clarified water eventually rises to the top
for reuse in the
process.
The bitumen froth is treated to remove air. The deaerated bitumen froth is
then diluted
with naptha and centrifuged to produce a bitumen product suitable for
upgrading. Centrifuging
also creates centrifugal tailings that contain solids, water, residual
bitumen, and naptha, which
can be disposed of in the tailings ponds.
More than 40 years of research and many millions of dollars have been devoted
to
developing and improving the Clark process by several commercial oil sands
operators, and by
the Alberta government. Research has largely been focused on improving the
process and
overcoming some of the major pitfalls associated with the Clark process. For
example, major
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bitumen losses from the conditioning tumbler, from the PSV and from the
subaeration cells.
Further, reaction of hot caustic soda with mined oil sands result in the
formation of naphthenic
acid detergents, which are extremely toxic to marine and animal life, and
require strict and costly
isolation of the tailings ponds from the environment for at least many
decades. Also, huge
energy losses due to the need to heat massive amounts of mined oil sands and
massive amounts
of water to achieve the required separation, which energy is then discarded to
the ponds. The
Clark process also results in loss of massive amounts of water taken from
water sources, such as
the Athabasca river, for the extraction process and permanently impounded into
the tailings
ponds that can not be returned to the water sources on account of its
toxicity. For example, to
produce one barrel of oil requires over 2 barrels of water from the Athabasca
River. The cost of
constructing and maintaining a large separation plant and the cost of
transporting mined oil sands
from a remote mining location to a large central extraction plant by means of
conveyors are
substantial in the Clark process. Additionally, the conveyors can be
problematic. The cost of
dilution centrifuging, naphtha recovery, maintaining and isolating huge
tailings ponds,
preventing leakage of toxic liquids from the tailings ponds, government fines
when
environmental laws are breached, and the eventual cost of remediation of mined
out oil sands
leases and returning these to the environment in a manner acceptable to both
the Alberta and the
Canadian government all present significant obstacles to long-term success of
the Clark process.
In addition, the environmental impact of the tailings ponds is a continual
point of concern for
operators of the Clark process and environmentalists.
Some major improvements have been made that included lowering the separation
temperature in the tumbler, the PSV, and the flotation cells. This reduced the
energy costs to a
degree but may also require the use of larger tumblers and the addition of
more air to enhance
bitumen flotation. Another improvement eliminated the use of bucket wheel
excavators,
draglines and conveyor belts to replace these with large shovels and huge
earth moving trucks,
and then later to replace some of these trucks with a slurry pipeline to
reduce the cost of
transporting the ore from the mine site to the separation plant. Slurry
pipelines eliminate the
need for conditioning tumblers but require the use of oil sand crushers to
prevent pipe blockage
and require cyclo-feeders to aerate the oil sand slurry as it enters the
slurry pipeline, and may
also require costly compressed air injection into the pipeline. Other
improvements included
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tailings oil recovery units to scavenge additional bitumen from the tailings,
and naptha recovery
units for processing the centrifugal tailings before these enter the tailings
ponds.
More recent research is concentrating on reducing the separation temperature
of the Clark
process even further and on adding gypsum or flocculants to the sludge of the
tailings ponds to
compact the fines and release additional water. However, adding gypsum hardens
the water and
this can require softening of the water before it can be recycled to the
extraction plant. Most of
these improvements have served to increase the amount of bitumen recovered and
reduce the
amount of energy required, but have increased the complexity and size of the
commercial oil
sands plants.
One particular problem that has vexed commercial mined oil sands plants is the
problem
of fine tailings disposal. In the current commercial process, mined oil sands
are mixed and stirred
with hot water, air, and caustic soda to form a slurry that is subsequently
diluted with cooler
water and separated in large separation vessels. In these vessels, air bubbles
attach to bitumen
droplets of the diluted slurry and cause bitumen product to float to the top
for removal as froth.
Caustic soda serves to disperse the fines to reduce the viscosity of the
diluted slurry and allows
the aerated bitumen droplets to travel to the top of the separation vessels
fast enough to achieve
satisfactory bitumen recovery in a reasonable amount of time. Caustic soda
serves to increase the
pH of the slurry and thereby imparts electric charges to the fines, especially
to the clay particles,
to repel and disperse these particles and thereby reduce the viscosity of the
diluted slurry.
Without caustic soda, for most oil sands the diluted slurry would be too
viscous for effective
bitumen recovery. It can be shown from theory or in the laboratory that for an
average oil sand,
it takes five to ten times as long to recover the same amount of bitumen if no
caustic soda is
added to the slurry. Such a long residence time would make commercial oil
sands extraction
much more expensive and impractical.
While caustic soda is beneficial as a viscosity breaker in the separation
vessels for
floating off bitumen, it is environmentally very detrimental. At the high
water temperatures used
during slurry production it reacts with naphthenic acids in the oil sands to
produce detergents
that are highly toxic. Not only are the tailings toxic, but also the tailings
fines will not generally
settle. Tailings ponds with a circumference as large as 20 kilometers are
required at each large
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mined oil sands plant to contain the fine tailings. Coarse sand tailings are
used to build huge and
complex dyke structures around these ponds.
Due to the prior addition of caustic soda, the surfaces of the fine tailings
particles are
electrically charged, which in the ponds, causes the formation of very thick
layers of microscopic
card house structures that compact extremely slowly and take decades or
centuries to dewater.
Many millions of dollars per year have been and are being spent in an effort
to maintain the
tailings ponds and to find effective ways to dewater these tailings. Improved
mined oil sands
processes must be commercialized to overcome the environmental problems of the
current
plants. One such alternate method of oil sands extraction is the Kruyer
Oleophilic Sieve process
invented in 1975.
Like the Clark Hot Water process, the Kruyer Oleophilic Sieve process
originated at the
Alberta Research Council and a number of Canadian and U.S. patents were
granted to Kruyer as
he privately developed the process for over 30 years. The first Canadian
patent of the Kruyer
process was assigned to the Alberta Research Council and, and all subsequent
patents remain the
property of Kruyer. Unlike the Clark process, which relies on flotation of
bitumen froth, the
Kruyer process uses a revolving apertured oleophilic wall (trade marked as the
Oleophilic Sieve)
and passes the oil sand slurry to the wall to allow hydrophilic solids and
water to pass through
the wall apertures whilst capturing bitumen and associated oleophilic solids
by adherence to the
surfaces of the revolving oleophilic wall.
Along the revolving apertured oleophilic wall, there are one or more
separation zones to
remove hydrophilic solids and water and one or more recovery zones where the
recovered
bitumen and oleophilic solids are removed from the wall. This product is not
an aerated froth
but a viscous liquid bitumen.
A bitumen-agglomerating step normally is required to increase the bitumen
particle size
before the slurry passes to the apertured oleophilic wall for separation.
Attention is drawn to the
fact that in the Hot Water Extraction process the term "conditioning" is used
to describe a
process wherein oil sands are gently mixed with controlled amounts water in
such a manner as to
entrain air in the slurry to eventually create a bitumen froth product from
the separation. The
Oleophilic Sieve process also produces a slurry when processing mined oil
sands but does not
"condition" it. Air is not required, nor desired, in the Oleophilic Sieve
process. As a result, the
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slurry produced for the Oleophilic Sieve, as well as the separation products,
are different from
those associated with the conventional Hot Water Extraction process. The
Kruyer process was
tested extensively and successfully implemented in a pilot plant with high
grade mined oil sands
(12 wt% bitumen), medium grade mined oil sands (10 wt% bitumen), low grade oil
sands (6
wt% bitumen) and with sludge from commercial oil sands tailings ponds (down to
2% wt%
bitumen), the latter at separation temperatures as low as 5 C. A large number
of patents are on
file for the Kruyer process in the Canadian and U.S. Patent Offices. These
patents include: CA
2,033,742; CA 2,033,217; CA 1,334,584; CA 1,331,359; CA 1,144,498 and related
US
4,405,446; CA 1,141,319; CA 1,141,318; CA 1,132,473 and related US 4,224,138;
CA
1,288,058; CA 1,280,075; CA 1,269,064; CA 1,243,984 and related US 4,511,461;
CA
1,241,297; CA 1,167,792 and related US 4,406,793; CA 1,162,899; CA 1,129,363
and related
US 4,236,995; and CA 1,085,760.
While in a pilot plant, the Kruyer process has yielded higher bitumen
recoveries, used
lower separation temperatures, was more energy efficient, required less water,
did not produce
toxic tailings, used smaller equipment, and was more movable than the Clark
process. There
were a number of drawbacks, though, to the Kruyer process.
One drawback to the Kruyer process is related to the art of scaling up.
Scaling up a
process from the pilot plant stage to a full size commercial plant normally
uncovers certain
engineering deficiencies of scale such as those identified below.
Commercial size apertured drums that may be used as revolving apertured
oleophlilic
walls require very thick perforated steel walls to maintain structural
integrity. Such thick walls
increase retention of solids by the bitumen and may degrade the resulting
bitumen product.
Alternately, apertured mesh belts may be used as revolving apertured
oleophilic walls. These
have worked well in the pilot plant but after much use, have tended to unravel
and fall apart.
This problem will likely be exacerbated in a commercial plant running day and
night. Rugged
industrial conveyor belts are available. These are made from pre-punched
serpentine strips of
flat metal and then joined into a multitude of hinges by cross rods to form a
rugged industrial
conveyor belt. Other industrial metal conveyor belts are made from flattened
coils of wire and
then joined into a multitude of hinges by cross rods to form the belts. Both
types of metal belts
were tested and have stood up well in a pilot plant. However, it was difficult
and energy
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intensive to remove most of the bitumen product in the recovery zone from the
surfaces of the
belts before these revolved back to the separation zone.
Bitumen agglomerating drums using oleophilic free bodies, in the form of
oleophilic
balls that tumbled inside these drums worked very well in the pilot plant.
However commercial
size agglomerators using tumbling free bodies may require much energy and
massive drum
structures to contain a revolving bed of freely moving heavy oleophilic balls
with adhering
viscous cold bitumen to achieve the desired agglomeration of dispersed bitumen
particles.
SUMMARY OF THE INVENTION
Accordingly, the present invention relates to apparatuses and methods for
separations.
Although the systems and methods have wide-spread application, in a specific
embodiment, the
separation mechanism can be based on the oleophilic and non-oleophilic nature
of components
of a flowable material.
The separation apparatus can include at least one endless cable. The cable can
be
wrapped multiple times around at least two revolvable cylindrical members. The
wrapping of
the cable can form gaps between adjacent windings that, along with the endless
cable, can
facilitate separation processes.
In one aspect of the present invention, the at least one endless cable
includes a first
multiple wrap endless cable wherein a first wrap, a plurality of subsequent
wraps and a final
wrap are formed by wraps of the first endless cable. In such embodiments, the
endless cable
passes over each of the cylindrical members a plurality of times.
Alternatively, the at least one endless cable can be formed of a plurality of
single wrap
cable loops such that each of the first wrap, subsequent wraps, and final wrap
are formed by a
corresponding single wrap cable loop. Such single wrap cable loops can be
composed of the
same materials as the multiple wrap endless cables where the single wrap cable
loops differ from
multiple wrap endless cables primarily in length. Single wrap cable loops are
configured to
rotate in a single loop, i.e. directly from one cylindrical member to another,
or possibly between
three or more cylindrical members in a single connected pass. The single wrap
loops do not
contact each of the cylindrical members a plurality of times, but rather
follow a single track or
path on a cylindrical member. In these embodiments, there is no need for
repositioning guides.
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The separation apparatus can further include a repositioning guide or guides
when the
endless cable is wrapped a plurality of times around the cylindrical members.
As the endless
cable moves along a route, the repositioning guide can ensure continuous
movement by allowing
a continuous path for the endless cable and by preventing the endless cable
from rolling off or
falling off of the cylindrical members.
In one aspect, the separation apparatus can include an oleophilic endless
cable. Such
apparatus can be used, e.g., for oleophilic-based separations such as bitumen
recovery from oil
sands. In a further aspect, the apparatus can include an agglomerator drum. An
agglomerator
drum can have openings oriented in fluid communication with the endless cable
to allow passage
of fluid from an interior to an exterior of the agglomerator drum. The
agglomerator drum can
also include oleophilic members for adhering oleophilic material. Such
oleophilic members can
be oleophilic baffles, tower packing or other suitable structures. A
separation apparatus
including an oleophilic endless cable and an agglomerator drum can have a
variety of
applications including, but not limited to, processing of bitumen and oil
products.
In another embodiment, the separation apparatus can include a gas inlet that
is oriented to
direct a gas through or across one or more flights of the endless cable or
cables. The apparatus
can further include a first liquid reservoir wherein the revolvable
cylindrical members include a
feed roller and an upper roller where the feed roller is contacted by liquid
from the first reservoir.
In still another embodiment, the separation apparatus can include one or more
endless cables
configured to be charged electrically with a high potential direct or
alternating current.
A separation apparatus of the type described herein can also or alternatively
be used as a
sand filter. In such embodiment, the revolvable cylindrical members can be
oriented to form an
upper flight and a lower flight of the at least one endless cable. The gaps
between adjacent
windings can be configured to be sufficiently narrow to allow passage of
liquid therethrough and
retention and conveyance of particulate solids thereon. In still another
embodiment, the
separation apparatus can be configured to size and sort particulate or other
material.
A method is also presented for separating that can include using an endless
cable. To
separate components of a flowable material, the material can be passed through
at least one
continuously moving endless cable. A first component can pass through gaps
between adjacent
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wrappings of the endless cable. A second component can be retained on or by
the endless cable,
which can then be partially or completely removed from the cable.
There has thus been outlined, rather broadly, various 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. Other features of the
present invention will
become clearer from the following 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. 1 a is a perspective view of a separation apparatus including two
revolvable
cylindrical members, and repositioning guide, according to one embodiment of
the present
invention.
FIG. 1 b is a cross-sectional view along line A-A of FIG. I a, illustrating
one aspect of the
present invention.
FIG. 1 c is an alternate cross-sectional view along line A-A of FIG. 1 a,
illustrating one
aspect of the present invention.
FIG. ld is an alternate cross-sectional view along line A-A of FIG. la,
illustrating
another aspect of the present invention.
FIG. 1 e is an alternate cross-sectional view along line A-A of FIG. 1 a,
illustrating still
another aspect of the present invention.
FIG. 2 is a side view of a separation apparatus including an agglomerator
oriented outside
the endless cable and above the top flight, according to one embodiment of the
present invention.
FIG. 3 is a side cross-sectional view of a separation apparatus including an
agglomerator
situated between the top and bottom flights of endless cable, according to one
embodiment of the
present invention.
FIG. 4a is an exploded perspective view of a separation apparatus including an
agglomerator situated between the top and bottom flights of endless cable,
where the
agglomerator includes a plurality of longitudinal baffles according to one
embodiment of the
present invention.
FIG. 4b is a perspective view of the agglomerator and endless cable of FIG.
4a.
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FIG. 4c is an exploded partial view of the longitudinal strips and end plate
of the
agglomerator shown in FIG. 4b.
FIG. 5a is a side view of an endless cable route where the endless cable is
configured to
travel around a revolvable member and come into close proximity with an
adjacent wrap of an
endless cable, according to one embodiment of the present invention.
FIG. 5b is a side view of a configuration where an endless cable travels
through a comb
to remove material therefrom, according to one embodiment of the present
invention.
FIG. 5c is a front view of a grooved scraper blade configured adjacent to a
grooved roller
to remove material from wraps of an endless cable, according to one embodiment
of the present
invention.
FIG. 5d is a front view of wraps of an endless cable passing through two
complimentary
grooved revolvable members, according to one embodiment of the present
invention.
FIG. 5e is a front view of wraps of an endless cable passing through two
revolvable
members, one of which is an impressionable rubber roller, according to one
embodiment of the
present invention.
FIG. 6 is a side schematic view of a system for removing hydrophilic solids
from
bitumen, including separations processing with an endless cable and a
serpentine pipe according
to one embodiment of the present invention.
FIG. 7 is a side view of an arrangement of an endless cable configured for
mass transfer
applications where the endless cable travels through a fluid reservoir, while
gas is directed to
travel past portions of the endless cable according to one embodiment of the
present invention.
FIG. 8 is a side view of an arrangement of another endless cable configured
for mass
transfer applications where the endless cable travels through four separate
fluid reservoirs,
according to one embodiment of the present invention.
FIG. 9 is a side view of an endless cable configured to carry a high potential
AC or DC
electric charge for defogging separations according to one embodiment of the
present invention.
FIG. l0a is a side view of another endless cable configured to carry a high
potential AC
or DC electric charge for electrostatic separations according to one
embodiment of the present
invention.
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FIG. 10b is a top view of FIG. 10a but not showing the bottom flight for
reasons of
simplicity of the Figure.
FIG. 11 a is a side view of an endless cable configured to act as a suspended
moving filter
according to one embodiment of the present invention.
FIG. 1 lb is a top view of FIG. l la but not showing the bottom flight for
reasons of
simplicity of the Figure.
FIG. 12a is a side view of an endless cable arranged to separate objects based
on size
according to one embodiment of the present invention.
FIG. 12b is a top view of one optional embodiment of FIG. 12a, but not showing
the
bottom flight for reasons of simplicity.
FIG. 13 is a top view of multiple endless cables arranged together to form a
conveyor
system according to one embodiment of the present invention.
It will be understood that the above figures are merely for illustrative
purposes in
furthering an understanding of the invention. Further, the figures are not
drawn to scale, thus
dimensions and other aspects may, and generally are, exaggerated or changed to
make
illustrations thereof clearer. Therefore, departure can be made from the
specific dimensions and
aspects shown in the figures in order to produce the separation system using
endless cables of the
present invention.
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.
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Definitions
In describing and claiming the present invention, the following terminology
will be used
in accordance with the definitions set forth below.
As used herein, the term "endless cable" refers 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 plastic rope, a single wire,
compound filament (e.g.
sea-island) or a monofilament which is spliced together to form a continuous
loop, e.g. by long-
splicing.
As used herein, "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. Likewise, referring
to a composition
as "conditioned" indicates that the composition has been subjected to such a
conditioning
process.
As used herein, "bitumen" refers to a viscous hydrocarbon that may include
maltenes and
asphaltenes that is found in oil sands ore interstitially between sand grains.
In a typical oil sands
plant, there are many different streams that may contain bitumen.
"Agglomeration drum" refers to a revolving drum containing oleophilic surfaces
that is
used to increase the particle size of bitumen in oil sand slurries prior to
separation. Bitumen
particles flowing through said drum come in contact with the oleophilic
surfaces and adhere
thereto to form a layer of bitumen of increasing thickness until the layer
becomes so large that
shear from the flowing slurry and from the revolution of the drum causes a
portion of the
bitumen layer to slough off, resulting in bitumen particles that are much
larger than the original
bitumen particles of the slurry.
As used herein, "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
specifically includes
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slurries (liquid with solid particulate), flowable dry solids, aerated
liquids, gases, and
combinations of two or more fluids. In describing certain embodiments, the
term slurry and
fluid may be used interchangeably, unless explicitly stated to the contrary.
The term, "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 the end point
of the pipe and is sufficiently remote from either end to achieve a desired
effect, e.g. washing,
disruption of agglomerated materials, etc.
As used herein, "velocity" is used consistent with a physics-based defmition;
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 are
specifically defined to
have substantially constant or gradually changing bulk directional velocity.
The term, "multiple wrap endless cable" as used in reference to separations
processing
refers to an 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. Movement of the endless
cable belt can be
facilitated by at least two guide rollers or guides that prevent said cable
from rolling off an edge
of the drum and guide the cable back to the opposite end of the same or other
drum. The spacing
in the endless belt is formed by the slits or gaps between sequential wraps.
The endless cable
can be a wire rope, a plastic rope, a single wire, compound filament (e.g. sea-
island) or a
monofilament which is spliced together to form a continuous loop, e.g. by
splicing. As a general
guideline, the diameter of the endless cable can be as large as 3 cm and as
small as 0.001 cm,
although other sizes might be suitable for some applications. An oleophilic
endless cable belt is
a cable belt made from a material that is oleophilic under the conditions at
which it operates.
As used herein, "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.
The term "cylindrical" indicates a generally elongated shape having a circular
cross-
section. Therefore, cylindrical includes cylinders, conical shapes, and
combinations thereof.
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The elongated shape has a length referred herein also as a depth as calculated
from one of two
points - the open vessel inlet, or the defined top or side wall nearest the
open vessel inlet.
As used herein, "recovery yield" refers to the percentage of material 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 would be a 95% recovery yield.
As used herein, the term "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 direction of the flow is directed by the shape
and direction of the
confining material.
As used herein, "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 one or more cables.
The term "roller" indicates a revolvable cylindrical member or drum, and such
terms are
used interchangeably herein.
As used herein, "wrapped" or "wrap" in relation to a cable wrapping around an
object
indicates an extended amount of contact. Wrapping does not necessarily
indicate full or near-full
encompassing of the object.
The term "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.
As used herein, the term "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
CA 02638596 2008-08-06
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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.
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 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 numerical value. Furthermore, such an interpretation should apply
regardless of the
breadth of the range or the characteristics being described.
Embodiments of the Invention
It has been found that a separation apparatus that is both versatile and
effective can be
created using one or more endless cables. The cable or cables can be wrapped a
plurality of
times around at least two revolvable cylindrical members. Such wrapping can
form a first wrap,
a plurality of subsequent wraps, and a final wrap for each endless cable. The
wrapping can be
from one cylindrical member to another, so that the one or more endless cables
contacts each of
the at least two cylindrical members multiple times to form gaps between
adjacent windings.
In one aspect of the present invention, the at least one endless cable
includes a first
multiple wrap endless cable wherein the first wrap, the plurality of
subsequent wraps and the
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final wrap are formed by wraps of the first endless cable. In such
embodiments, the endless
cable passes over each of the cylindrical members a plurality of times. This
is the embodiment
illustrated in FIGs. la, 4 and others as discussed in more detail below. In
order to avoid an
unacceptable amount of cable twisting as the cable is wrapped around the
cylinders, the endless
cable can be formed, e.g. by long splice, having a twist opposite to that
created when wrapping.
In this way the wrapped endless cable can avoid excessive twist or bending.
Alternatively, the at least one endless cable can be formed of a plurality of
single wrap
cable loops such that each of the first wrap, subsequent wraps, and final wrap
are formed by a
corresponding single wrap cable loop. Such single wrap cable loops can, in one
embodiment, be
composed of the same materials as the multiple wrap endless cables. Single
wrap cable loops
typically differ from multiple wrap endless cables primarily in size. Cable
loops are configured
to rotate in a single loop, i.e. from one cylindrical member to another, or
possibly between three
or more cylindrical members. The single wrap loops do not contact each of the
cylindrical
members a plurality of times, but rather follow a single track or path on a
cylindrical member. In
this embodiment, there is no need for repositioning guides.
A separation apparatus can further include a repositioning guide or guides for
each ofthe
multiple wrap endless cables. As the endless cable moves along a route, the
repositioning guide
can be oriented to continuously allow guidance of the final wrap of a multiple
wrap endless cable
to roll into and assume the position of the first wrap, thus preventing the
endless cable from
rolling off or falling off the cylindrical members.
General
FIG. 1 is a perspective view of a single multiple wrap endless cable 2 wrapped
between
two revolvable cylindrical members 4, 6 multiple times. As illustrated, the
wrapping forms a
first wrap 8, a plurality of subsequent wraps 10, and a final wrap 12. A
repositioning guide
support 14 is shown including two guide rollers 16, 18. The final wrap 12
travels from the
revolvable cylindrical member 6 to the first guide roller 16, and then to a
second guide roller 18,
where it is repositioned as the first wrap 8. Shown is a basic concept of an
endless cable belt
wrapped, in this case, around two rollers in a large number of wraps using a
single endless cable.
A number of different configurations are possible by variations in number of
endless belts,
number, size and position of revolvable members, and various repositioning
guides.
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In FIG. 1 a, a drive roller 6 and tension roller 4 are used. The drive roller
initiates and
maintains rotation of the roller, which, in turn, causes the endless cable 2
to rotate along the
endless path. The drive roller can be rotated via a drive belt 7 and motor,
not shown, or other
suitable mechanism. The tension roller can be maintained an adjustable
distance from the drive
roller that maintains the endless cable at a tension that allows for use in
separations processing
and keeping the cable in track. For example, cables may stretch during use
requiring periodic
tension adjustment. The desirable tension can vary greatly and will depend on
the anticipated
application and type and size of endless cable. Tension adjustment may
alternately be provided
by a guide or guide rollers or one or more tension rollers.
The endless cable can be configured in a variety of ways. FIG. 1 a shows line
A-A, along
the path of the endless cable along the top flight of the endless cable. FIGs
lb through le
illustrate various embodiments of endless cable arrangements as seen across
the line A-A. FIG.
1 b is a cross-sectional view of a single, multiwrap endless cable wrapped
around two revolvable
members, as illustrated in FIG. 1 a. FIG. 1 c shows two multiwrap endless
cables which are
wrapped on the rollers in alternating wraps. The empty circles refer to the
first cable and the
filled-in circles refer to the second cable. In this case two repositioning
guides are required
instead of one. FIG. 1 d is a cross-section of an embodiment of FIG. 1 a where
one endless cable
is wrapped around the main rollers of FIG. 1 a, with the addition of grizzly
bars situated in gaps
between adjacent wraps. The grizzly bars (indicated by triangles in the
Figure) can be stationary
or vibrate in a vertical or orbital plane. These grizzly bars, in conjunction
with the revolving
wraps create shear or vibration that, in some cases, may enhance the operation
of the endless
cable belt, and may provide support to the upper flight of the endless cable
so that it will not sag
or deflect unacceptably under the weight of material on top of the flight or
by the movement of
material through the gaps. Although the grizzly bars are shown having a
triangular cross-section
with one flat edge upward, other cross-sectional shapes can be suitable such
as, but not limited
to, rectangular, circular, trapezoidal, or the like. FIG. 1 e is similar to
Figure 1 c in that two
multiple wrap endless cables are used, but in this case, the wraps are grouped
together per
endless cable and not intertwined. Again, a repositioning guide is used for
each endless cable in
this case. If four endless cables are used, then four repositioning guides may
be required. Each
of the configurations shown in FIG. 1 b through 1 e can also be applied to the
lower or bottom
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flight as an alternative to the upper flight or in combination with the same
or different
configurations on the top flight.
When more than one endless cable is used, it is preferred that the
repositioning guides, or
another element other than a revolvable member jointly used by the multiple
endless cables, be
used to provide the desired tension for each cable individually. Controlling
tension of multiple
endless cables using a common tensioner or tension roller is possible, but can
be difficult in
some embodiments. One method of providing satisfactory tension along the top
flight of a group
of a large number of single wrap endless cables is to allow slack along the
bottom flight. For
example, both main rollers in Figure 1 a could be driven counter clockwise.
When each main
roller is provided with a squeeze roller and the left main roller is driven at
a slightly higher
surface speed than the right main roller, the top flight would be in tension
and the bottom flight
could be slack. The slackness of the bottom flight would accommodate any small
changes in the
lengths of the individual single wrap endless cables while allowing the top
flight to remain tight
and serve the desired separating function. When more than two main rollers are
used to support
the single wrap endless cables, then two sets of squeeze rollers can be
dedicated to provide the
desired cable slack over a section of the apparatus whilst maintaining the
desired cable tension
for the rest of the apparatus. In this case, the set of squeeze roller feeding
the cables into the
slack section can be driven at a slightly higher surface speed than the
surface speed of the other
main rollers; and the slack section could be anywhere along the endless cables
as desired, and
would not necessarily have to form the bottom flight.
The endless cable or cables can comprise or consist essentially of a member
selected
from the group consisting of metal, plastic, fiber, and combinations thereof.
All of the endless
cables can be of the same composition, or, each can independently comprise or
consist
essentially of a member selected from the group consisting of metal, plastic,
fiber, and
combinations thereof. In one embodiment, at least one endless cable can
comprise or consist
essentially of single strand or multi strand steel, galvanized steel, tin
coated steel, clad steel,
plastic coated steel cable, copper, stainless steel, titanium, wire rope,
twisted plastic rope,
braided polymeric rope, carbon fiber rope, single monofilament rope, and
combinations thereof.
The desirability of a particular material for use as the cable can depend on a
variety of factors,
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not limited to, strength, availability, cost, electrical conductivity,
hydrophobicity, particular
application, and the like.
The endless cable can be of any size that allows for arranging the endless
cable to wrap
around at least two revolvable cylindrical members in a manner that
facilitates separations
processing. As such, appropriate endless cable sizes are dependent on the type
of separation, the
weight and size of material to be separated, the endless pathway through which
the endless cable
travels, the gap size, etc. In a specific embodiment, one or more of the
endless cables can have a
diameter ranging from about 0.02 cm to about 3 cm. In a further embodiment,
one or more of
the endless cables has a diameter ranging from about 0.1 cm to about 1.0 cm.
Separations or gaps between windings at least partially result from the
winding route of
the endless cable. The gaps can be configured to allow material to flow
through in the desired
manner, e.g. increasing surface contact with fluids without hindering flow
through gaps,
retaining larger materials above while allowing smaller materials to pass
through the gaps, etc.
As illustrated in FIG. 1a, the gaps between adjacent windings can be
substantially uniform.
Alternatively, the gaps can be non-uniform or variable. In one aspect, the
gaps between adjacent
windings are from about 1% to about 10% or in some cases 50% of a diameter of
the endless
cable. In some embodiments, the gaps between adjacent windings range from
about 50% to
about 600% of the cable diameter, or more. The specific size of the gaps may
vary greatly due to
the application, type of separation desired, type of endless cable, etc. As a
non-limiting example,
and in one embodiment, the gaps can range in size from about 0.02 cm to about
5 cm, or from
about 0.1 cm to about 2.0 cm.
Endless cables are continuous and include no recognizable beginning or ending.
Such
endless cables can be created by joining the ends of a single cable. The
joining mechanism can
be any type for which the separation apparatus and separations process allows.
A basic example
that could be used in a very forgiving system is a simple knot or crimped
sleeve. Preferably, the
cable is joined in a manner that leaves no noticeable area, but allows for a
seamless transition
from beginning to end of the cable. A long splice can be used in such
situations. Such cables
can, in some instances, include multiple cablesjoined together to form a
single endless cable. In
one aspect, an endless cable can include more than one standard long splice to
join cable ends
and to make one cable endless. A "long splice" is a well known method of
joining cables in a
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manner which does not significantly increase the cable diameter at the splice
but results in a
splice that has almost the same strength as the cable itself.
There are a wide variety of arrangements of at least one endless cable wrapped
between
at least two cylindrical members. More than one endless cable could be used.
More than two
cylindrical members can be used, in which case, the route of the endless cable
may not be
directly from one cylindrical member to another, but may include a more
intricate or circuitous
route. An endless cable can be wrapped any number of times around some or all
cylindrical
members. For example, at least one endless cable of a separation apparatus can
wrap around at
least two of the cylindrical members of the separation apparatus from about 10
to about 1000
times. In a relatively simple variation of the single endless cable wrapped
around two cylindrical
members design, a second endless cable can be wrapped a plurality of times
around the same two
cylindrical members. Furthermore, the second endless cable can be wrapped
around any number
of cylindrical members, associated with the first endless cable or following a
different path. In
one embodiment including a second endless cable, the wraps of the second
endless cable can be
grouped together and located adjacent to the group of wraps of the first
endless cable.
Alternatively, the wraps of the second endless cable can alternate with the
wraps of the first
endless cable, or rather each succeeding wrap of the second endless cable
individually can be
located adjacent to each succeeding wrap of the first endless cable.
In another design variation, the cylindrical members can number more than two.
For
example, the cylindrical members in one embodiment can range from 3 to 10.
Multiple
cylindrical members can be oriented to also contact the at least one endless
cable a plurality of
times to form the gaps between adjacent windings. Such orientation may cause
the same number
of wraps or contacts with more than one of the cylindrical members, or may
leave one or more
rollers with more or fewer contacting cable passes. The two or more
cylindrical members may
have substantially the same diameter, or may have differing diameters
depending the particular
application and system design. In one embodiment, at least one of the
cylindrical members has a
diameter from about 10 cm to about 1000 cm.
In order to facilitate proper or improved flow of the fluid or solids, various
parts of the
separation apparatus can vibrate. Vibration can help to prevent clustering and
agglomeration of
material and break up previously agglomerated materials. In one aspect, one or
more of the
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cylindrical members can be configured to vibrate. Alternatively, or in
addition, the endless cable
can be configured to vibrate. Material separation may be further improved by
including an
optional material distributor. Such material distributor can be configured to
distribute material
over at least a portion of the gaps between adjacent windings of an endless
cable. Non-limiting
examples of material distributors include screens, perforated sheets, parallel
support grizzly bars,
and combinations thereof. Such material distributors can be configured to
vibrate to better
improve the desired separation.
Once components of the fluid are separated, each component can be collected in
a
separate collection apparatus. The separation apparatus can, therefore,
include a pass-through
outlet oriented to collect material which passes through the gaps of the
endless cable. The
separation apparatus can also include a retained outlet oriented to collect
material retained on the
at least one endless cable. In one aspect, such pass-through outlet or outlets
are positioned under
a generally horizontally-oriented endless cable. Similarly, a corresponding
retained outlet can be
positioned near a cylindrical member, and often near a stripping device which
removes material
retained on or by the endless cable. In some embodiments, a portion of the
fluid is retained by
the endless cable by a manner of adhering or sticking to the cable rather than
temporarily resting
on the cable. In such cases, it may be necessary to strip the material from
the cable. Such
stripping can occur at regular or semi-regular intervals, and can continuously
occur during
processing and operation of the separation apparatus. Non-limiting examples of
cable stripping
devices include rubber squeeze rollers, complimentary grooved rollers, combs,
grooved knife,
cross-cables, steam heat zones, inductive heat zones, microwave heat zones,
and combinations
thereof. In one aspect, a separation apparatus including an endless cable can
include one or more
wash water sources oriented to wash material adhered to an endless cable.
Additionally or
alternatively, a separation apparatus can include one or more dryers
configured and oriented to
dry material adhered to an endless cable.
As discussed, a repositioning guide can include a plurality of guides
configured to guide
an endless cable along a continuous or endless path. Such repositioning guide
or guides can be
spaced apart from the at least two revolvable cylindrical members. A
repositioning guide or
guides can, in addition to moving the endless cable from the last wrap to the
first wrap, be
configured to control location and spacing of gaps. The revolvable cylindrical
members can
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include a variety of surfaces. In one aspect, the surface of at least one
cylindrical member can be
smooth. Alternatively, the surface can be treated to have an abrasive surface.
In one aspect, the
surface can include a mild adhesive. In still another aspect, at least one of
the revolvable
cylindrical members can be a grooved cylindrical member including grooves on
an exterior
surface of the grooved cylindrical member. The grooves can be configured to
control location
and spacing of the gaps. Generally, any approach which can be used to maintain
adjacent wraps
or windings of the endless cables can be used in the present invention.
Oleophilic Separations
In one embodiment, one or more of the endless cables of a separation apparatus
can be
oleophilic. One or more oleophilic endless cables can be wrapped a multitude
of times around
two main rollers to form an endless cable belt. When such wrapping are between
two or more
rollers or cylindrical members that are horizontally spaced apart, the wraps
can form a top flight
and a bottom flight. Such is the case with FIG. 2 which illustrates two
cylindrical members 22,
24 or rollers of different sizes. With at least one endless cable 26 traveling
between the
cylindrical members in a continuous path facilitated by the repositioning
guide 28. In one
aspect, one roller can be a driving roller, while the other roller is
adjustable to maintain the
desired tension in the wraps to prevent these wraps from sagging. The
repositioning guide can
optionally include two or more guide rollers that are spring loaded to
maintain approximately
equal tension in the wraps when one or more than one oleophilic cable is used.
In one aspect of using an oleophilic endless cable, oil sand slurry or
desanded oil sand
slurry forms the feed. As shown in FIG. 2, the feed 29 is directed into an
agglomerator 30
positioned above the top flight 32 of the endless cable 26. The agglomerator
can be configured
to revolve. Although a variety of agglomerator configurations could work with
the design
presented, in one aspect, the agglomerator can have a central cylindrical
apertured screen 33 and
an outer cylindrical apertured screen 35 to allow the flow of slurry from the
centre of the
agglomerator, out through the outer screen and onto the top flight of the
oleophilic endless belt.
The annular volume between the inner screen 33 and the outer screen 35 of the
agglomerator 30 can optionally be filled with oleophilic tower packings or
other suitable
agglomerating members, e.g. fixed baffles, etc. As slurry flows through this
volume, bitumen
from the slurry temporarily adheres to the surfaces of the agglomerating
members and then
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sloughs off in the form of enlarged bitumen particles. The enlarged bitumen
particles are
captured more readily by the oleophilic endless cable belt than small bitumen
particles.
As shown in FIG. 2, bitumen is captured and retained by the endless cable 26
as the
slurry from the agglomerator 30 passes through the top flight 32. A bitumen-
reduced slurry
passes through the top flight. The retained bitumen is conveyed towards and
along the main
roller 24 at the right until it encounters the squeeze roller 36 mounted along
this main roller. The
squeeze roller removes bitumen from the belt as it revolves with this main
roller by preventing
bitumen from passing between the two rollers. Bitumen accumulates on the
underside of the two
rollers and sloughs off. The thus removed bitumen can be collected as a
primary product in a
first product collector 38. At least a portion of residual bitumen in the
bitumen-reduced slurry
can be captured as slurry passes from the top flight through the bottom flight
34. Slurry which
passes through the bottom flight can be primarily non-oleophilic and can be
collected and
directed to the tailings reservoir 40. Residual bitumen retained by the bottom
flight can be
collected with a squeeze roller 42 along the left main roller 22 in a similar
manner as with
squeeze roller 36. Bitumen removed from the bottom flight can be collected in
a second product
collector 44. The first and second bitumen products can be combined for
further processing or
treated independently.
Baffles 46 can optionally be mounted between the top flight 32 and the bottom
flight 34
to direct bitumen-reduced slurry from the top flight to the bottom flight and
to keep it away from
the main rollers 22, 24. In some cases, a mesh screen 48 or several mesh
screens can be placed
above the bottom flight between the baffles to slow down the flow of slurry
impacting onto the
bottom flight. This is done to minimize dispersion of residual bitumen
droplets that fall from the
top flight to the bottom flight and to improve contact between the bottom
flight of endless cable
and the slurry.
FIG. 3 illustrates another embodiment of a separation apparatus including an
oleophilic
endless cable 60. This configuration can be used to separate oil sand slurry
or desanded oil sand
slurry in two stages, although other materials may also be effectively
separated in this manner.
One or more endless cables 60 are wrapped a multitude of wraps around rollers
62, 64, 66 and
agglomerator drum 68 to form an endless belt. Guides or guide rollers are used
as in the
previous embodiments and previous figures, but these are not shown for reasons
of clarity.
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Stage 1 separation occurs along the top flight 70 and stage 2 separation
occurs along the bottom
flight 72 in conjunction with an agglomerator 68 optionally filled with
oleophilic tower
packings. Oleophilic tower packings are used extensively in the refining
industry for distillation
columns and in extraction columns and are often made from polypropylene,
polyethylene or
from other plastics, although metal packings could also be used.
Slurry feed flows onto the top flight 70 from a dispenser 74 that spreads it
evenly over
the endless belt. A screen 76 or several screens may optionally be used under
the dispenser to
better distribute and slow down the flow of slurry onto the top flight.
Bitumen captured from the
slurry by the top flight is conveyed to the set of squeeze rollers 64, 66
where the bitumen is
squeezed off the belt by these two rollers and then flows into a pipe 78 or
other receiver as a
primary bitumen product. Tailings 86 from stage 1, primarily including water,
solids and some
bitumen, pass through the gaps of the top flight and flow into a reservoir 80
connected with a
pipe to a central inlet of the agglomerator 68. A pump, not shown, may
optionally be used to
convey these tailings to the agglomerator. In the agglomerator bitumen
particles of these tailings
are further agglomerated by the oleophilic tower packings. These bitumen
particles temporarily
adhere to the oleophilic surfaces of the tower packings and form a layer of
bitumen on the
surfaces of these packings. This layer of bitumen increases in thickness until
shear from water
and solids, flowing through the packings, sloughs off bitumen in the form of
enlarged bitumen
particles, which are then captured by the bottom flight 72 as these leave the
agglomerator.
Bitumen thus captured by the bottom flight is conveyed to another set of
rollers 81, 62, where it
is squeezed off the belt and flows into a pipe 82 or other receiver as a
bitumen product. Tailings
from stage 2 drop into a tank 84 under the agglomerator and bottom flight and
are sent to
dewatering and disposal. These tailings are preferably substantially free of
bitumen, although
some residual bitumen is sometimes present. In addition, the baffles andlor
packing material
used as agglomerating members can further augment oleophilic separation of
bitumen from
aqueous portions. More particularly, water has a viscosity substantially lower
than that of the
bitumen. As a result, water and bitumen located near a bottom region of the
agglomerator will
experience different rates of sloughing from the internal agglomerating
members. In the
embodiment shown in FIG. 3 the endless cable is traveling in a clockwise
direction. As such,
loose internal packing material will tend to accumulate and pile up along the
inner left region of
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the agglomerator. Whether the packing material and/or larger baffles are used,
bitumen which
adheres thereto tends to slough off later than water and aqueous portions,
i.e. in the lower to mid
left internal region. This also has a beneficial affect of reducing potential
for plugging of the
lower bottom flight near contact with the agglomerator drum. Furthermore, the
bitumen adhered
to the bottom flight tends to vary in thickness when the flight is inclined,
i.e. thinner near the
contact point with the drum and thicker as at approaches the upper squeeze
rollers 62 and 81.
These effects also allow for a decrease in rotational speed of the drum and
endless cable for a
given flow rate.
Optionally, wash water may be used to wash adhering solids from bitumen on the
top
flight and air may be used to blow dry this bitumen. However such washing or
drying may only
be used as needed or desired.
Free bodies, such as 1 or 2 inch grinding balls or balls similar to golf balls
or a mixture
thereof may be used as the agglomerating medium in an agglomerator of the
instant invention.
Such balls tumble with the bitumen and tend to kneed the bitumen and, in many
cases, assist in
the agglomerating process by stripping fine solids from the surface of the
bitumen and thereby
encourage bitumen to agglomerate more readily. However care must be taken to
prevent the
charge of balls from becoming so heavy that the agglomerator drum becomes like
a ball mill
requiring a very heavy drum with a resulting heavy support structure.
Alternative to the tower
packings or other free bodies, the agglomerator 68 can include a plurality of
internal baffles. In
this case, tailings that have passed through the gaps of the top flight 70
fall onto a baffle, which
directs these tailings into the volumes between oleophilic baffles of the
agglomerator. The
velocity of these tailings is such, and the angle of the oleophilic baffles is
such, that the tailings
are scooped up by the baffles and flow towards the centre of the agglomerator.
Bitumen
particles remaining in the tailings of the top flight come in contact with
oleophilic baffles of the
agglomerator and temporarily adhere thereto until the layer of bitumen on the
baffles becomes
thick enough that shear from the flowing tailings sloughs off the bitumen in
the form of enlarged
bitumen particles. Then, as the agglomerator revolves, these tailings
containing residual bitumen
reverse direction with respect to the agglomerator centre and flow outward
past the baffles of the
agglomerator, and towards the bottom flight 72 for capture of bitumen by the
bottom flight.
Bitumen product from the bottom flight is removed by means of squeeze rollers
81, 62, or is
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removed by other means. Wash water and air (not shown) may be used along the
bottom flight
as well, but only as needed or desired, to wash solids from the bottom flight
and dry the contents
of the bottom flight.
It should be noted that the agglomerator can have endwalls to contain the
tailings from
the top flight, but these are not shown in FIG. 3 for the sake of clarity. In
one embodiment, the
oleophilic baffles are attached to and are supported by steel bars or strips
that connect to the
endwalls of the agglomerator. FIG. 4a shows an exploded perspective view of
such an
agglomerator 69 incorporated into a separation apparatus similar to that of
FIG. 3. In particular,
an endless cable 61 is wrapped around the agglomerator and between two
separate sets of
squeeze rollers 63 and 65 using two tension rollers 67 and 71. A dispenser 73
can be used to
distribute slurry across the top flight of the endless cable system, either
with or without
additional screening or distributors. As described previously, oleophilic
materials within the
slurry tend to adhere to the endless cable while other non-adhered portions
pass through the top
flight and onto a collection pan 75. The collection pan can direct the
partially separated slurry
onto the agglomerator 69 through the gaps between the oleophilic baffles.
Bitumen removed
from each of the sets of squeeze rollers can be collected in hoppers 77 and
79, respectively.
Similarly, material and fluids which pass through the agglomerator are
collected in vessel 85 and
drained via line 83.
As shown in FIG. 4b, the agglomerator has an endwall 95 (shown removed) which
includes slanted notches 97 for receiving notched longitudinal strips 99 (in
this case 26 such
strips). These strips are notched or grooved to keep the wraps of the endless
cable belt in
alignment and to maintain the gaps or apertures between these wraps at
constant width. FIG. 4c
illustrates an exploded view where each single strip 99 has a plurality of
alignment grooves 101
which are oriented facing outward of the drum as can be seen in FIG. 4b and
4c. Retaining holes
103 can be used to attach suitable oleophilic baffles 105. Referring again to
FIG. 4b, as slurry
flows across the longitudinal strips 99 and oleophilic baffles 105 additional
bitumen is adhered
to and agglomerates along these structures. The rotational speed of the
agglomerator is sufficient
to allow agglomerated bitumen to collect and flow towards the lower flight of
the endless cable
where it is collected and carried towards squeeze rollers 63.
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In one aspect of the present invention, the endless cable can separate a first
component
that is a hydrophilic material and the second component that is an oleophilic
material. It is
understood that recovery yields may not, and usually will not, reach 100% such
that some minor
amount of hydrophilic material may be present in the oleophilic product and
visa-versa. In
another aspect, a first separation product or component can primarily include
water and a second
component can primarily include bitumen. In one embodiment, the flowable
material further
includes a member selected from the group consisting of clay, silt, sand, and
mixtures thereof.
Various yield recoveries can be achieved by varying different aspects of the
separation apparatus
and can depend on the characteristics of the slurry or fluid. However, in one
specific
embodiment with bitumen separations, the bitumen can be separated from the
slurry at a bitumen
recovery yield of greater than about 95 wt %, although actual recovery yields
can vary
depending on the grade of oil sand used as a feed. As an illustration, for a
poor quality beach
sand containing 6% bitumen, recovery may be as high as 60%. For a medium grade
oil sand
containing 10% bitumen, recovery can exceed 92%, and for high grade oil sand
ore containing
12% bitumen recovery may exceed 95%.
As previously mentioned, various methods for mechanically removing bitumen
from the
oleophilic endless cable belt are shown in FIGs 5a through 5e. The temperature
of bitumen
adhering to the cable belt can be left unaltered and the bitumen can be
recovered by the methods
shown in, e.g., FIGs 5a - 5e and alternatively or additionally, the cable
wraps and the bitumen
may be heated in the recovery zone using steam, heated gas, microwaves,
electricity, or other
heat source to reduce the bitumen viscosity. The more fluid bitumen can then
be scraped or
squeezed off more effectively by methods similar to the mechanical methods
shown in FIGs 5a-
5e. Bitumen may also be heated by internally heating the main rollers and/or
the recovery rollers
with steam or other means.
In FIG. 5a, cable 110 is wrapped around a roller 112 such that throughout the
endless
belt, each cable wrap before contacting this roller, and following its
contour, is scraped on either
side by two adjacent cable wraps at the location 113 where the cable wraps
cross. When the slits
or gaps between adjacent cable wraps are equal to the diameter of the cable,
such crossing of the
cable wraps serves to comb bitumen from each cable wrap approaching the
roller. This method
is particularly useful when the slits are equal to or only slightly larger
than the cable diameter. A
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blade (not shown) under and in contact or near contact with the cable cross
can facilitate
removing bitumen from the cable wraps at the crossing location. Bitumen thus
removed from
the wraps falls or flows into a suitable receiver.
FIG. 5b uses a comb 118 to remove bitumen from the cable 116. Tines of the
comb are
shaped and placed between the cable wraps and the back of the comb can either
be above the
wraps or below the wraps. Bitumen combed from the wraps falls or flows away
from the comb
into a receiver. The comb can be shaped to have complimentary grooves with the
cable wraps.
Further, the comb can be formed of any suitable material such as, but not
limited to, ultra-high
density polyethylene, stainless steel, Teflon-coated materials, polycarbonate,
and the like.
FIG. 5c uses a scraper blade 122, e.g. of ultra high density polyethylene,
machined to
follow the contour of the cable wraps 120 on a main roller 124, which is
grooved and made of
wear resistant material or surface such as those listed above. While scraping,
this blade will
slowly wear and form itself to fit closely around the contour of the
individual wraps as it scrapes
bitumen from the roller and from the cable wraps.
FIG. 5d uses a main roller 130 and a recovery roller 132 having complimentary
grooves
which allow the cable to pass through. Both rollers are grooved and made from
wear resistant
metal and/or are hard surfaced. The grooves are machined to tolerances that
will force most of
the bitumen to be squeezed off the wraps 134 before the wraps pass between the
rollers.
Bitumen thus forced from the wraps is collected in a receiver below the wraps
or rollers.
FIG. 5e is similar to FIG. 5d except that the recovery roller 140 is a rubber
or
impressionable roller pressing against the main roller 138, the rubber being
deformed to the
contour of the cable wraps on the main roller in order to squeeze bitumen off
the wraps 142. The
recovery roller may be made from rubber, urethane or any flexible wear
resistant material
commonly used for the fabrication of flexible long lasting rollers.
Another method for removing at least a portion of a second component, such as
bitumen,
from the endless cable includes heating the endless cable. Since the specific
heat of water may
be approximately ten times as great as the specific heat of the endless cable,
the endless cable
rapidly cools down when again coming into contact with the aqueous mixture it
separates and
thus continues to serve well in capturing bitumen at the mixture temperature
of the instant
invention. Optionally, the heated endless cable can be cooled or washed by
rinsing with water
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and/or cooled gas. Regardless, excessive heating of the endless cable can be
avoided which
might otherwise reduce adherence of bitumen during subsequent passes or cause
carbon
formation on the cable surface.
An endless cable separation apparatus can be a portion of a process for
removing
hydrophilic solids from bitumen froth or from bitumen product. Bitumen product
or bitumen
froth from an oil sand extraction process normally contains water and solids
which
conventionally are removed by means of dilution centrifuging. This entails
deaerating the froth
with steam after which the deaerated froth or the bitumen product are mixed
with a light
hydrocarbon, such as naphtha, heated and centrifuged. The products of dilution
centrifuging are
clean diluted bitumen, which after naptha removal, is suitable for long
distance pipelining or
upgrading to synthetic crude oil, and centrifugal tailings which contain
water, solids, some
naphtha and some bitumen. Dilution centrifuging is a costly operation and any
pretreatment
which will remove even a portion of the solids and/or water from bitumen froth
or from bitumen
product is beneficial in reducing the cost of subsequent dilution
centrifuging. Alternatively, a
cleaner bitumen product may eliminate dilution centrifuging and allow the use
of cheaper
processing and upgrading. Thus, the separation apparatuses of the present
invention can be
advantageously used to treat bitumen or bitumen froth prior to dilution
centrifuging.
One alternative embodiment of an overall bitumen clean up process is shown in
FIG. 6.
Bitumen product or bitumen froth, water and a suitable chemical (for example a
demulsifier) can
be introduced into the pump 150 and from there flow through a serpentine pipe
152 described in
the Isoelectric Application. The serpentine pipe can act to dislodge
hydrophilic solids from
bitumen and thus improve bitumen quality. High pressure water may optionally
be injected
through a side inlet 154 of the serpentine pipe if so desired to further
dislodge or disengage
hydrophilic solids from bitumen. Initially, in the bitumen product feed or in
the bitumen froth,
bitumen forms the continuous phase and water forms the dispersed phase. In the
serpentine pipe,
water and chemicals thoroughly mix with the bitumen product or the bitumen
froth to such a
degree that bitumen becomes the dispersed phase and water becomes the
continuous phase.
Hydrophilic particulates previously trapped in the bitumen phase or in the
dispersed water phase
are released and report to the now continuous aqueous phase.
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This dispersion then flows into an agglomerator 156 surrounded by an
oleophilic endless
cable belt 158 with the agglomerator as one of the revolvable cylindrical
members in the
assembly, as described in detail previously. Dispersed bitumen droplets adhere
to the tower
packings of the agglomerator and grow in size due to adherence to the
oleophilic surfaces of the
tower packings and subsequently sloughing off in the form of enlarged bitumen
droplets. From
the agglomerator, the mixture flows to the oleophilic endless cable belt where
bitumen is
captured by the wraps of the cable belt whilst water and hydrophilic
particulates pass through the
gaps of the endless cable belt to a receiver 160 and from there to dewatering
and disposal.
Bitumen is recovered from the belt by methods described in the instant
invention and collected in
a bitumen product collector 162.
Non-limiting examples of suitable chemicals that may be used in the processing
may
include demulsifiers, acids, buffers or divalent salts to reduce
emulsification ofthe mixture in the
serpentine pipe. For example, an acid or buffer may be used if the bitumen
froth contains water
having a high pH which tends to encourage the formation of tight bitumen in
water emulsions in
the serpentine pipe. A divalent salt, such as gypsum may be used if the
bitumen froth contains
natural detergents which also tend to encourage the formation of hard-to-break
bitumen in water
emulsions in the serpentine pipe. The gypsum would tend to counteract the
emulsion formation
tendency of the natural detergent by hardening the water.
In an alternate design, the tower packings in the agglomerator can be replaced
by other
oleophilic members for adhering oleophilic material. The agglomerator drum in
this
embodiment, as well as other embodiments, can be situated adjacent to the gaps
of the endless
cable between adjacent windings and sufficient to allow material to flow from
an interior volume
of the agglomerator drum through the gaps of the endless cable wraps.
In another embodiment, the agglomerator drum can be one or more of the
revolvable
cylindrical members between the endless cable wraps. The agglomerator drum in
this case can
be positioned between the top flight and the bottom flight of the endless
cable, and can be
adjacent to the gaps between adjacent windings sufficient to allow material to
flow through the
gaps of the top flight, or a direct feed, and into the interior volume of the
agglomerator drum and
from the interior volume of the agglomerator through the gaps of the bottom
flight of said
endless cable wraps. Alternatively, the revolving agglomerator drum can be
spaced from and
CA 02638596 2008-08-06
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oriented either between the top flight and the bottom flight or above the top
flight. Much
discussion has been directed to revolving or moving agglomerators, however, in
one aspect, an
agglomerator drum can be a stationary vessel.
One method of assembling an agglomerator drum for use in the present
application
includes assembling a plurality of longitudinal strips oriented substantially
parallel to one
another, spaced apart, and oriented to form a cylindrical shape. The strips
can be attached at
ends to two end discs, one end disc at each end. In one aspect, the
longitudinal strips can include
notches spaced and oriented to maintain the gaps between adjacent windings of
the at least one
endless cable, as described in connection with FIGs. 4a-4c.
As may be necessary, the separation apparatus disclosed herein can be located
in a
variety of locations. A non-limiting example of a location is underground or
inside a mine shaft.
Such placement can allow for more efficient removal of materials from mining-
type operations
of a deeply buried oil sand deposit in situ and prior to transport of bitumen
product to the
surface. In this case some or all the tailings may need to be transported to
the surface as well.
Oil sand ore normally is very tightly packed and when this ore is disturbed
and separated it will
tend to fluff up and create more volume than the ore originally in place.
In yet another embodiment of the present invention, the endless cable device
can be used
to recover bitumen from conventional caustic tailings found in tailings ponds
associated with the
Clark process or other similar processes. Current commercial developers of the
Clark process
see a tailings pond as a means for storing toxic tailings and recovering water
for reuse in the
commercial process but generally do not use a pond as part of the process for
recovering
bitumen. As a result, the current commercial plants go to great lengths and
expense recover
bitumen from the warm tailings before they flow into the ponds and loose their
elevated
temperatures. However, in accordance with the present invention, a large
amount of additional
bitumen may be recovered as such a tailings pond is incorporated into a
bitumen recovery
process utilizing the endless cable devices of the present invention. At
current commercial
tailings ponds, sand and silt settle out of the tailings and water floats to
the top, leaving a sludge
containing bitumen, clay fines and water present in a bitumen-rich middlings
portion of the pond
(e.g. below the water rich layer and above the sand and silt layer). The
percent bitumen content
of this sludge can be an order of magnitude greater than the bitumen content
of the tailings
CA 02638596 2008-08-06
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flowing into the pond. In some cases, on a dry basis percentage, sludge may
contain as much
bitumen as mined oil sand ore. As long as the ponds are not abandoned, this
bitumen is not lost
but collects in the ponds and may be recovered by oleophilic devices described
in this or in the
Endless Cable application. Such separation may be carried out at very low
temperatures, even
approaching zero degrees centigrade when centrifugal tailings (or tailings
from other types of
hydrocarbon bitumen clean up) are blended with primary and secondary tailings
flowing into the
pond thereby reducing the viscosity of bitumen of primary and secondary
tailings by residual
solvent contained in the centrifugal tailings. Without such blending, the
separation of sludge
from primary and secondary tailings may be carried out by oleophilic means
around 10 C to
20 C. The bitumen rich sludge can be collected using a suitable mechanism,
such as but not
limited to, pumping with an intake set at the appropriate depth. The collected
sludge can then be
directed to the endless cable as either the sole feed (optionally mixed with
water or other
additives to control flowability) or in combination with a crushed sands
slurry or other materials
as discussed previously.
When a tailings pond becomes part of the bitumen recovery process of a
commercial oil
sands plant, and oleophilic means can be used to recover this bitumen.
Allowing bitumen to
accumulate and concentrate in tailings ponds and then recovering this bitumen
at a later date can
effectively increase overall annual commercial plant bitumen recovery after
the commercial
plant has been in operation for some time. Since caustic process aid is used
in the current
commercial plants, the debitumenized sludge left after recovering bitumen from
a current
commercial tailings pond (e.g. using the Clark process or its equivalent)
remains toxic.
Mass Transfer
The endless cable belt of the present invention may be used for a range of
chemical
engineering mass transfer applications. These may include among others:
drying, freeze drying,
evaporating, humidifying, gas cleaning, reacting of components in a gas with a
liquid, etc. In the
application illustrated in FIG. 7, a gas 170 is passed through slits between
sequential wraps of
the endless cable 172. Although not shown in this figure, a plurality of wraps
can optionally be
oriented substantially parallel as described previously. A feed reservoir 174
and a product
reservoir 176 are also shown. As the endless cable passes through liquid in
the feed reservoir,
some liquid adheres to the endless cable and is drawn upward into a contact
region where gases
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are directed. The gas-liquid contacting can result in a wide variety of mass
transfer, chemical
reactions or other processes. For example, the feed liquid may be a liquid
reactant and the gas
may contain or consist essentially of a corresponding gas reactant. Gaseous
products or
components can be reacted with or be collected and liquid products can be
formed and retained
on or by the endless cable. Product reservoirs are not required for simple
drying, for example,
and only one reservoir may be used for humidifying or evaporating, unless the
process of
humidifying or evaporating results in the production of salts or more
concentrated liquids. An
optional scraper or a comb may be used to remove crystals from the cable or to
remove
concentrated liquids and/or liquid products. Furthermore the two rollers 178,
180 above the
product reservoir can serve to squeeze liquid from the cable or to break
crystals from the cable.
In gas cleaning or in reacting a liquid with the components or impurities in a
gas stream, one or
several more reservoirs may be required, depending upon the complexity of the
unit operation. It
should be noted that enclosures, drives, gas inlets and outlets and other
auxiliary components are
not shown for clarity but are well within the skill of those in the art.
FIG. 8 illustrates a more complex mass transfer unit than FIG. 7, and includes
four liquid
reservoirs 188, 190, 192, and 194. This embodiment includes an enclosure 196,
a gas inlet 198,
a gas outlet 200, one or more endless cable belts 202, nineteen main
cylindrical members 204,
and repositioning guides 206 to keep the endless cable or cables on the
cylindrical members in
the same manner as previously described. In one aspect, two or more of the
separate reservoirs
can include a distinct liquid composition therein or may contain a common
liquid which is
recoated over the endless cable upon each pass into the corresponding liquid
reservoir. As with
other embodiments, when more than one endless cable is used, a guide or set of
guide rollers is
required for each endless cable, unless single wrap endless cables are used.
Such individual
repositioning guides may also provide proper tension to the cables. Note that
the cable or cables
run from main roller to main roller in sequence and return along the top of
the figure. In one
aspect, one or more of the main rollers can be grooved to accept the cable and
maintain
predetermined gap distances. The concepts disclosed with FIG. 7 will apply to
FIG. 8 in many
instances, and visa versa.
Generally speaking, an apparatus of this type, when dealing with gas-liquid,
can include a
gas inlet oriented to direct a gas across a flight of the at least one endless
cable, and a first liquid
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reservoir. In one aspect, the revolvable cylindrical members can include a
feed roller and an
upper roller, where the feed roller is oriented within the first liquid
reservoir to contact liquid
therein, and the upper roller is remote from the first liquid reservoir.
Optionally, alternating
upper rollers or respective grooves can be offset from adjacent upper rollers
such that adjacent
flights of the endless cables are offset in order to allow incoming gases to
be more fully exposed
to each flight and reduce channeling through unobstructed gas flow paths. The
apparatus can
optionally include a cable stripping device for use in removing a product
material and/or excess
liquid adhered to the endless cable.
Electrically Charged Devices
One or more endless cables can be electrically charged to achieve specific
separation
results as explained in more detail below. However, when an oleophilic cable
is electrically
charged it tends to become less oleophilic due to the mechanism of
electrowetting. This means
that oil adhering to a cable may become coated with a continuous film of water
instead of with
water droplets when an electric potential is applied to the cable.
Alternately, water may seek to
wet part of the cable itself under certain conditions when the cable is
electrically charged. This
mechanism of electrowetting can be used to advantage for removing bitumen or
oil from such a
cable in a recovery zone.
FIG. 9 illustrates another embodiment of an endless cable separation
apparatus. This
application uses an endless cable 220 that is configured to be charged
electrically with a high
potential direct or alternating current of a first polarity or phase via a
suitable electrical source.
In one aspect, the endless cable and two or more revolvable cylindrical
members 222,224 can be
oriented within a containment vesse1226. The containment vessel can optionally
be electrically
charged with a high potential direct or alternating current of a second
polarity or phase opposite
the first polarity or phase.
The endless cable can be configured to use high voltage AC or DC to separate
mixtures.
High voltage can be used along with low current flow. In one aspect, one
polarity or phase of
the high voltage may be attached to the wraps of an endless cable belt and the
other polarity or
phase may be attached to an external electrode or an adjacent wrap of another
endless cable belt
such that the wraps of one endless cable are intertwined with the wraps of
another endless cable
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and are of opposite polarity or phase. FIG. 9 may use the second polarity or
phase attached to an
external electrode 228 surrounding the insulated enclosure 230 of the
apparatus.
This embodiment was tested to condense a petroleum fog resulting from the
rapid
cooling of a hydrocarbon gas in the presence of finely dispersed particulate
matter. The
particulate matter formed the nucleus of oil droplets upon condensing of the
hydrocarbon gas,
resulting in a fog that was very difficult to break. When the electricity was
turned off, a dense
fog formed in the apparatus. However, in about a second, after 15,000 volts of
AC was turned
on, the fog broke and produced a clear gas with liquid flowing down the walls
of the glass
enclosure and along the cable. Particulate matter tended to collect on the
cable, which was then
wiped clean with a scraper.
Another embodiment is illustrated in FIG. l Oa and FIG. l Ob. The main rollers
244, 246
are insulated. The endless cable belt 248 can be used as an electrostatic
precipitator or coalescer
of aqueous phase dispersed in a continuous hydrocarbon phase. A high voltage
DC imparts a
charge to the dispersed phase as the fluid passes through the gaps of the top
flight 250. Then, as
these charged droplets pass the bottom flight 252, they are attracted to the
cables that are of the
opposite polarity. When a high voltage AC is used, the dispersed phase
droplets vibrate due to
the alternating field and some of these droplets coalesce as they come in
contact with each other
while passing through the top or bottom flight.
Alternately, this apparatus of FIG. IOa-lOb can be used as a multi cable
separation
apparatus to break a hydrocarbon fog or mist as described with FIG. 9. FIG. I
Oa-I Ob provides a
different view or embodiment of such a device which differs in one main
aspect. The device of
FIG. 9 uses a single endless cable belt whilst the device of FIG. l0a-l Ob
uses two endless cable
belts, although additional endless cables can be used. Thus, the device of
FIG. l0a-l Ob uses at
least two endless cable belts which are wrapped alternately upon the main
rollers 244, 246 to
make an intertwined cable device. One cable is charged with a high voltage DC
potential orh.igh
voltage AC phase. The other cable is charged with a high voltage DC of
opposite polarity or
with a high voltage AC of the opposite phase. This results in the presence of
a high electric
potential between adjacent wraps on the insulated rollers. The high voltage DC
or AC is applied
to the cables by means of the repositioning guides 254, 256 for each endless
cable.
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When a comb or scraper 258 is used to remove water or solids from the cables,
it often is
more convenient to use four rollers in order to have a region where the cables
of opposite
polarity are not close to each other. In those spaced regions a comb or a
knife can be used to
remove solids or water from the cables without danger of bridging the gap
between cables of
opposite polarity with water or wet solids which might create electrical
discharge in view of the
high potential electricity used. A four roller device therefore, would prevent
or reduce electrical
shorts or sparking.
Slurry Filter
A moving bed filter can be created by the use of one or more endless cables
wrapped a
plurality of times with very small gaps around two or more rollers. The
sequential wraps can be
close enough to form only very narrow gaps or slits through which liquid can
flow readily but
which prevent the undesirable passage of particulates of the medium to be
filtered or dewatered.
Undesirable passage of particulates would be any amount that can be
substantially reduced
without substantially blocking passage of liquids therethrough.
A two level filter is shown as FIGs. 11 a-11 b, which uses one endless cable
270. The
endless cable acts as a wet or dry sieving sifter or as a slurry dewatering
device for a liquid
slurry, e.g., desanded tailings from an oil sands process. For example, a
screened underflow 272
of a hydrocyclone mainly containing coarse sand can be deposited first onto an
upper flight of
the filter. The underflow can be distributed onto almost the full width of the
filter to form a
moving bed of coarse particulates. For simplicity in the drawing, the
distributor is here shown as
a pipe only. It is to be understood that other distributors can be used which
more fully spread the
slurry of the upper flight. The wraps of the endless cable are close enough
together to prevent
coarse sand from passing through the apertures. Again, for sake of
illustration clarity, the wraps
are shown here much wider apart. The small rollers 274 in FIG. l lb indicate
that the wraps are
kept close together. Generally, gaps between wraps can be distanced apart from
about 0.5 mm to
about 3 mm, although other gap spacings may be suitable for particular
embodiments and
slurries. In this case, it may not be as useful to have grooves in the
rollers. The twist of a
conventional wire rope will normally provide voids adequate for passage of
water between the
wraps, even when the extremities of the individual wraps are touching. The
useful size of gaps
depends on many variables of the apparatus, including intended application,
intended separation,
CA 02638596 2008-08-06
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composition and size of endless cable, composition and particle sizes in the
slurry, etc.
However, in a specific embodiment, the average gaps between adjacent windings
are about 0.01
cm to about 0.1 cm.
After the coarse sand bed is established, desanded tailings 276 can be
deposited on top of
the bed created by the coarse sand 272. The coarse sand then acts as a
filtering medium for the
desanded tailings which contain water and fines, including fine sand, silt and
clay, as well as a
small amount of bitumen. These fines would normally pass through the gaps
between the cable
wraps, but the coarse sand bed underneath prevents or reduces such passage.
Dewatered
particulates and coarse sand leave the top flight 278 of the filter as a
bottom layer and dewatered
desanded tailings leave the filter as a top layer. The bottom flight 280 of
the filter may be
shaken, washed, or blasted with air when it becomes necessary to continuously
remove from the
bottom flight sticking particulates or bitumen. As with any other embodiment,
the main rollers
do not have to be the same size. Additional materials can be added to the top
flight, and the
general concept may be used for other filtering purposes, either as a single
stage moving filter or
as a multi stage moving filter. In this case the liquid may be water or any
other liquid from
which particulates are to be recovered.
Generally, a filter can be formed of the apparatus where at least two of the
revolvable
cylindrical members are oriented to form an upper flight and a lower flight of
the endless cable
or cables. The upper flight can be within 45 of horizontal, and the gaps
between adjacent
windings can be configured to be sufficiently narrow to allow passage of
liquid therethrough and
retention and conveyance of particulate solids thereon having a predetermined
particle size. The
apparatus can further include a liquid collection vessel oriented below the
first flight and
configured to receive the liquid. Additionally, a first slurry outlet can be
included, which can be
configured or oriented to deposit a first coarse slurry onto the upper flight.
Similarly, a second
slurry outlet can be included that is oriented to deposit a second slurry onto
the upper flight
subsequent to the first coarse slurry. Further, the separation apparatus can
optionally include a
cleaning mechanism operatively associated with the bottom flight to remove
debris and material
from one or more of the endless cables.
CA 02638596 2008-08-06
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Physical Separations
The endless cable belt of the instant invention provides for a large range of
apparatus
options. In one aspect, it may be used as a particle sizing device which moves
various fractions
to the appropriate bins in a separation process. FIG. 12a illustrates a simple
configuration
designed to separate a particulate feed into two fractions. Feed is introduced
via hopper 300 to
the top flight 302 and one larger fraction 304 is removed from the top flight
and a second smaller
fraction 306 passes through both flights and leaves from the bottom flight
308. Thus, the flight
gaps between wraps can be adjusted to screen varying particle sizes from one
another to achieve
the desired wet or dry sieving.
Alternative embodiments include a receiving bin for the third, fourth and
fifth fraction,
for example, which may be placed under the top flight or flights. This is
accomplished when the
gaps or apertures between sequential cable wraps increase from one side to
another, as in FIG.
12b. This is shown for a simple non-vibrating sizing apparatus in FIG. 12b. In
this case, guides
310 may be useful to keep the endless cable 312 in the grooves of the
appropriate roller.
Alternatively, additional rollers can be oriented parallel to the outer
rollers over which wraps are
wound or past over in order to produce multiple zones where gap distances vary
in each zone.
For example, four size ranges can be produced using four rollers (first
through fourth parallel
rollers oriented in a plane in numerical order left to right) where the first
and second rollers have
x wraps, the third roller has x/2 wraps, and the fourth roller has x/4 wraps.
In such a case, each
subsequent zone, i.e. from left to right, will have a gap distance which is
double that of the
previous zone. Similarly, multiple separation apparatuses can be oriented in
series and/or
parallel to further separate the particulate material into additional size
ranges. In such cases,
each separation apparatus can have gap spacings designed and optimized for
separation of a
particular size fraction.
FIG. 13 illustrates still another separation application wherein the endless
cable is used as
a conveyor system for separating objects which are retained on the endless
cable. A package 320
moves along an endless cable belt 322 main conveyor in the direction shown by
the arrow. One
or a plurality of endless cable belt secondary conveyors 324, 326 revolve
under the main
conveyor. Two such secondary conveyors are shown, although additional
secondary conveyors
can be added. Sets of pins 328 and 330 are located at the gaps between the
cables of the
CA 02638596 2008-08-06
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overlapping conveyors in a diagonal arrangement. These are pins or rollers,
and the elevation of
these pins is electronically or otherwise controlled using conventional
mechanisms, e.g.
hydraulic, electronic motor, spring, etc. When the package is to be directed
to the left, onto the
first secondary conveyor 324, the corresponding pins 328 are raised, i.e., by
computer. When the
package is to be directed to the right onto the second secondary conveyor 326,
the corresponding
pins 330 are raised. The processing can be fully automated by including
sensors to detect bar
codes on packages. These bar codes can be read by the computer which can then
control onto
which secondary conveyor the package is directed using conventional sorting
and inventory
software. In this manner a large number of packages, objects, parts, parcels
or letters may be
directed rapidly and automatically to their respective desired destinations.
The use of pins or
rollers 328 and 330 are possible because the endless belt of the instant
invention does not contain
cross members or cross wraps which in a conventional conveyor belt would
interfere with such
pins or rollers located or rising up between the cable wraps or between
longitudinal members of
the belt.
Of course, it is to be understood that the above-described arrangements, and
specific
examples and uses, are only illustrative of the application of the principles
of the present
invention. Numerous modifications and alternative arrangements may be devised
by those
skilled in the art without departing from the spirit and scope of the present
invention and the
appended claims are intended to cover such modifications and arrangements.
Thus, while the
present invention has been described above with particularity and detail in
connection with what
is presently deemed to be the most practical and preferred embodiments of the
invention, it will
be apparent to those of ordinary skill in the art that numerous modifications,
including, but not
limited to, variations in size, materials, shape, form, function and manner of
operation, assembly
and use may be made without departing from the principles and concepts set
forth herein.
