Note: Descriptions are shown in the official language in which they were submitted.
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HYDROCYCLONE AND ASSOCIATED METHODS
RELATED APPLICATIONS
This application claims priority to U.S. Patent 7,708,146, entitled
"Hydrocyclone and
Associated Methods," filed November 14,2007, and U.S. Patent Application
2009/0122637 Al,
filed June 3, 2008.
FIELD OF THE INVENTION
The present invention relates to devices and methods for hydraulically sorting
of fluids
after these have been processed by static mixing and/or shearing of fluids, or
by other methods.
Accordingly, the present invention involves the fields of process engineering,
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
40years, bitumen in McMurray oil sand has been commercially 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.
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
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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
15 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
20 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
25 overcoming some of the major pitfalls associated with the Clark process.
For example, major
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
30 energy losses due to the need to heat massive amounts of mined oil sands
and massive amounts
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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 also required 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
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
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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. For
most oil sands without caustic soda, 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
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
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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
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
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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
oleophilic
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
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 heavy
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
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adhering viscous cold bitumen to achieve the desired agglomeration of
dispersed bitumen
particles.
As such, improvements to methods and related equipment for recovery of bitumen
from
oil sands continue to be sought through ongoing research and development
efforts.
SUMMARY OF THE INVENTION
Accordingly, the present invention relates to the separation of mined oil
sands or bitumen
containing mixtures by an endless oleophilic belt formed by wrapping an
oleophilic endless wire
rope a plurality of times around two or more drums or rollers to form a
multitude of sequential
oleophilic wraps wherein hydrophilic materials including water and hydrophilic
solids pass
through the spaces or voids between said sequential wraps in a separation zone
and oleophilic
materials including bitumen and oleophilic solids are captured by the
oleophilic wraps for
subsequent removal in a recovery zone. Before mined oil sands can be
separated, bitumen can
be disengaged from the sand grains by a mixing and/or shearing action in the
presence of a
continuous water phase.
This present invention relates particularly to a hydrocyclone and a related
method for
separating components from a fluid or from an oil sand slurry after it has
been processed in a
pipe or pipeline sufficient to disengage at least a portion of bitumen from
sand particles of the
slurry. In one aspect, the hydrocyclone can be used to de-sand a slurry
including bitumen and
solid particulate such as gravel, sand, silt and clay. The hydrocyclone
includes a helical confined
conduit connected to and upstream of a substantially open cylindrical vessel.
The connection
from the helical confined conduit to the open vessel, or open vessel inlet,
can be configured to,
without substantial disturbance, introduce a fluid tangentially from the
helical confined conduit
into the open vessel. The hydrocyclone can further include an overflow outlet
and an underflow
outlet, both operatively attached to the open vessel. The underflow outlet can
be attached at a
location on the open vessel that is substantially opposite the helical
confined conduit and open
vessel inlet. The overflow outlet can be configured to terminate at one end at
a vortex finder
that is positioned in an interior of the open cylindrical vessel and has a
substantially enclosed
conduit from the vortex finder to an exterior of the open cylindrical vessel.
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Likewise, a method for separating components from a fluid can include guiding
the fluid
along a helical path at high velocity to form a helically flowing fluid. The
method can further
include tangentially injecting the helically flowing fluid smoothly at high
velocity into an open
vessel to cause the fluid to rotate along a swirl path within the open vessel.
The rotation along
the swirl path of the fluid can be sufficient to produce an overflow and an
underflow. A rinse
fluid can be injected tangentially into at least one of the helical path and
the swirl path. The
underflow and the overflow can be removed from the open vessel. The rinse
fluid generally
includes or consists essentially of water, although other fluids or additives
can be used.
Such hydrocyclone and methods can be used for a variety of applications, and
specifically for de-sanding aqueous fluids containing bitumen. In a further
embodiment, the
fluid can include gravel, sand, fines, bitumen and water, and can produce an
overflow primarily
of bitumen, fines and water, while the underflow includes gravel and coarse
sand.
In the Clark process, air is added in the oil sand slurry preparation process
to cause bitumen
to rise to the top of separation vessels and this is not required for
separation by the Kruyer process.
However, when an oil sand slurry is prepared and transported in a pipe, and is
then separated by a
hydrocyclone into an underflow of coarse solids in water and an overflow of
fine solids and
bitumen in water, some of the bitumen will remain captured in the voids
between the coarse
particulates. Thus, in accordance with one embodiment of the present
invention, small bubbles of
gas can be introduced in the outer flow path of the helical confined conduit
and/or in the open
vessel to scavenge for small trapped bitumen droplets and cause their adhesion
to these gas bubbles
to change the bulk density of the trapped bitumen and cause the bitumen
droplets to move away
from the outer flow path due to the centripetal forces acting on the fluid in
this conduit or in the
open vessel. The amount of gas required to scavenge for these trapped bitumen
droplets is
relatively small and in some cases this gas may be absorbed in the bulk of the
slurry liquid after the
scavenged bitumen droplets have moved away from the coarse solids and have
joined the bulk of
the fine solids and water on their way to the overflow of the hydrocyclone.
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.
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BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1A is an elevated perspective view of a hydrocyclone according to one
embodiment
of the present invention.
FIG. 1B is a side view of the hydrocyclone of FIG. 1A.
FIG. 1C is an end view of the hydrocyclone of FIG. 1A.
FIG. 2A is an elevated perspective view of a hydrocyclone according to another
embodiment of the present invention.
FIG. 2B is a side view of the hydrocyclone of FIG. 2A, according to one
embodiment of
the present invention.
FIG. 2C is an end view of the hydrocyclone of FIG. 2A.
FIG. 3A is a side view of a hydrocyclone in accordance with yet another
embodiment of
the present invention having a conical outlet end.
FIG. 3B is an end view of the hydrocyclone of FIG. 3A.
FIG. 4 is a side view of a portion of a helical confined conduit comprising
multiple
coupled pipe elbows, in accordance with one embodiment of the present
invention.
FIG. 5 is a plan top view of a hydrocyclone with a helical confined conduit in
the form of a
spiral, in accordance with an embodiment of the present invention. The
flanges, although not
required, are added to make it easier in the figure to follow the curve of the
conduit.
FIG. 6 is a side view of the hydrocyclone of FIG. 5. In this case, the
hydrocyclone uses an
overflow that leaves from the top and an underflow that leaves from the bottom
of the open vessel,
in accordance with an embodiment of the present invention.
FIG. 7 is a sectional view of an outer curved wall of a helical confined
conduit showing a
nozzle mounted on and through this wall, in accordance with an embodiment of
the present
invention.
FIG. 8 is a schematic illustration of the contents of a helical confined
conduit showing the
coarse solids flowing along the outer curved wall and showing the effect of
gas bubbles from a
nozzle attaching to bitumen droplets and causing the density reduced bitumen
droplets to move out
of the voids between the coarse solids towards the opposite wall of the
conduit due to centripetal
force, in accordance with an embodiment of the present invention.
FIG. 9 is a cross-section of a set of joined structural channels used to form
a helical
confined conduit in accordance with one embodiment of the present invention.
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FIG. 10 is a cross-section of a set of joined structural channels used to form
a helical
confined conduit having intermediate members spaced between the channels in
accordance with one
embodiment of the present invention.
FIG. 11 is a cross-section of the joined channels of FIG. 9 showing a circular
flange.
FIG. 12 is a cross-section of the joined channels of FIG. 10 showing a square
flange.
It will be understood that the above figures are simplified and are merely for
illustrative
purposes in furthering an understanding of the invention without in any way
limiting any
applications or aspects 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 hydrocyclone 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 pump" includes one or more of such pumps,
reference to "an
elbow" includes reference to one or more of such elbows, and reference to
"injecting" includes
reference to one or more of such actions.
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, "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 the 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
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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, "bitumen" refers to a viscous hydrocarbon, including maltenes
and
asphaltenes, that is found in oil sands ore interstitially between the sand
grains. In a typical oil
sands plant, there are many different streams that may contain bitumen.
As used herein, "central location" refers to a location that is not at the
periphery,
introductory, or exit areas. 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, "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, e.g. by flotation.
Likewise, referring
to a composition as "conditioned" indicates that the composition has been
subjected to
conditioning.
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 which is directed by the
shape and direction of
the confining material. Although typically provided by a pipe, baffles or
other features can also
create a confined path.
As used herein, the term "cylindrical" indicates a generally elongated shape
having a
substantially circular cross-section. Therefore, cylindrical includes
cylinders, conical shapes,
and combinations thereof. The elongated shape has a length referred herein to
as a depth
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, "disengagement" and "digesting" of bitumen are used
interchangeably,
and refer to a primarily physical separation of bitumen from sand or other
particulates in mined
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oil sand slurry. Disengagement of bitumen from oil sands occurs when physical
forces acting on
the oil sand slurry results in the at least partial segregation of bitumen
from sand particles in an
aqueous medium. Such disengagement is intended to be an alternative approach
to conventional
conditioning, although disengagement could optionally be performed in
conjunction with
conditioning.
As used herein, the "isoelectric point" of a slurry or its clay fines
component is the point
at which the electric charges on the double layer surrounding clay particles
are close to zero, e.g.
substantially zero, or are zero. The isoelectric point can be determined by
measuring the zeta
potential of the clay fines in suspension and also is indicated to some degree
by the viscosity of
the slurry. Close to the isoelectric point the slurry generally has a higher
viscosity than further
away from the isoelectric point since electric charges generally disperse the
clay fines and the
absence of electric charges generally discourages dispersion of the clay
fines. Dispersion of the
fines commonly is achieved by increasing the pH of the slurry above the
isoelectric point or
decreasing the pH of the slurry below the isoelectric point.
As used herein, "endless cable belt" when 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 the cable
from rolling off an edge
of the drum or roller and guide the cable back onto a drum or roller. The
apertures in the endless
belt are the slits or gaps between sequential wraps. The endless cable can be
a wire rope, a
plastic rope, a metal cable, 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 2 cm and as small as 0.001
cm, although other
sizes might be suitable for some applications. An oleophilic endless cable
belt is an endless
cable belt made from a material that is oleophilic under the conditions at
which it operates.
As used herein, "fluid" refers to flowable matter. Fluids, as used in the
present invention
typically include a liquid or gas, and may optionally further include amounts
of solids and/or
gases dispersed therein. As such, fluid specifically includes slurries (liquid
with solid
particulate), aerated liquids, and combinations of the two fluids. In
describing certain
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embodiments, the term slurry and fluid may be interchangeable, unless
explicitly stated to the
contrary.
As used herein, "helical" refers to a shape which conforms to a spiral or
twisted
configuration where multiple, generally circular, loops are oriented along a
central axis
substantially perpendicular to a plane of the loops. A helical shape is
commonly seen in springs
where consecutive loops are stretched along the central axis, although a
compacted helical path,
i.e. a flat spiral, and the like can also be suitable. Further, the cross-
sectional shape can deviate
from regular circular and/or can have a constant curvature. For example, a
helical shape can
have an elliptical cross-section, have a non-constant curvature so as to
produce a conical helical
shape, and/or can have one or more passes which are skewed or slanted from
perpendicular to
the central axis. Consistent with this definition, a "helical path" is a path
which follows a helical
shape and is generally "confined" to such a path by physical barriers such as
pipe walls. Such
helical shape can include a coil shape, wherein the shape most represents a
stretched spring.
Alternatively, the helical shape can include a planar helical shape, known as
a spiral, wherein the
path is in a single plane and is a curve which emanates from a central point,
getting progressively
farther away as it revolves around the point, such as the spiral conduit shown
in FIG. 5. In terms
of flow path, the flow gets progressively closer to the central point in such
spiral embodiments.
As used herein, 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. Non-limiting examples of metals are Ag, Au, Cu, Al, and Fe. In
one aspect,
suitable metals can be main group and transition metals. Metalloids include
specifically Si, B,
Ge, Sb, As, and Te, among others. Metallic materials also include alloys or
mixtures that
include metallic materials. Such alloys or mixtures may further include
additional additives.
As used herein, "open cylindrical vessel" refers to a vessel which is
substantially free of
internal structures and/or obstructions other than those explicitly identified
as present, e.g. a
vortex finder. An open cylindrical vessel can often be a completely vacant
cylindrical vessel
having various inlets and outlets as identified with substantially no other
structures present
within the vessel other than an optional vortex finder.
As used herein, "overflow" refers to a more central portion of a swirl flow,
and as such,
is often the more valuable fluid containing fines and bitumen. "Underflow"
likewise refers to a
CA 02638550 2008-08-07
. -14-
more circumferential portion of a swirl flow and typically contains coarser
material and is often
drawn off as effluent and/or for further processing. Often, a processed fluid
is split into a single
overflow and single underflow, although multiple overflow and/or underflows
may be useful.
As used herein, "series" represents a number of more than two. A series of
nozzles, for
example, can be three nozzles, four nozzles, five nozzles, etc. The series of
nozzles can be
regularly placed or irregularly placed, with respect to distance between
nozzles.
As used herein, "operatively associated with" refers to any functional
association which
allows the identified components to function consistent their intended
purpose. For example,
units such as pumps, pipes, vessels, tanks, etc. can be operatively associated
by direct connection
to one another or via an intermediate connection such as a pipe or other
member. Typically, in
the context of the present invention, the units or other members can be
operatively associated by
fluid communication amongst two or more units or devices.
As used herein, "periodically crosses" refers to a regular crossing or
traversing of
particles at periodic intervals (i.e. regular or irregular, but repeating)
across the bulk flow of a
flowing fluid.
As used herein, the term "hydrocyclone" is used interchangeably with
"separating
apparatus," where both terms indicate the equipment, as described herein,
beginning with the
helical confined conduit and including the open vessel with an underflow and
an overflow.
As used herein, "repeating sinusoidal wave in a two-dimensional plane" refers
to a shape
that, when viewed from a projected side view, has the characteristics of a
repeating harmonic
wave, i.e. a sinusoidal wave. As such, the sinusoidal wave may in some cases
be defined or
described in terms associated with sine waves. A repeating sinusoidal wave,
according to the
present invention, has amplitude and periods. The sinusoidal wave can be
deformed, can have
delays in period, and can be dampened in all or some of the length of the
wave. The pipe in the
shape of the wave is not necessarily in a two-dimensional plane of motion. In
a specific
embodiment, the sinusoidal pipe is substantially two-dimensional and can be
described as
serpentine. Alternatively, the sinusoidal pipe can have three-dimensional
aspects such that at
least a portion of the path is out of plane. However, the sinusoidal wave of
the present invention
is distinct from helical or spiral shapes in that that repeating sinusoidal
wave has a velocity
directional vector that alternates, whereas spiral and helical shapes are
subject to velocity
CA 02638550 2008-08-07
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directional vectors that are rotational-based and relatively constant about an
axis of rotation.
Specifically, repeating sinusoidal waves according to the present invention do
not have
identifiable axes of rotation parallel to the length of the pipe for longer
than one period of
repetition of the sine wave shape. At times, and for ease of discussion, the
term "repeating
sinusoidal wave in a two-dimensional plane" may be shortened to "sinusoidal
wave."
As used herein, "swirl path" refers to a flow pattern which generally follows
an
unconfined helical path, although significant mixing and chaotic flow occurs
along the axis of
overall flow down the length of a vessel. A swirl path is generally produced
by introducing
fluids tangentially into a generally cylindrical vessel thus producing flow
circumferentially as
well as longitudinally down the vessel length. Although a helical path and
swirl path have
similar general shapes, a helical path is generally used herein in reference
to a confined helical
flow while a swirl path refers to an unconfined, generally helical, swirl
flow.
As used herein, "velocity" is used consistent with a physics-based definition;
specifically,
velocity is speed having a particular direction. As such, the magnitude of
velocity is speed.
Velocity further includes a direction. When the velocity component is said to
alter, that indicates
that the bulk directional vector of velocity acting on an object in the fluid
stream (liquid particle,
solid particle, etc.) is not constant. Spiraling or helical flow patterns are
specifically defined to
have substantially constant or gradually changing bulk directional velocity.
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
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, "vortex finder" refers to a centrally located pipe within a
hydrocyclone
for the purpose of removing overflow from the hydrocyclone. The vortex finder
can be a simple
pipe having an unrestricted open pipe entrance and, alternately may be
provided with a flange at
CA 02638550 2008-08-07
-16-
the pipe entrance as well, to encourage overflow to find its way from the
hydrocyclone interior
into the vortex finder opening.
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 cm to about 5
cm" should be interpreted to include not only the explicitly recited values of
about 1 cm to about
5 cm, 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. Consistent with this
principle the term "about"
further includes "exactly" unless otherwise stated.
Embodiments of the Invention
It has been found that fluids having components of different densities and/or
containing
different particle sizes, particularly those including particulate and liquid,
can be effectively
separated using a hydrocyclone having a helical confined path immediately
upstream of a
substantially open cylindrical vessel. Hydrocyclones of the present invention
can be used as a
separating mechanism for a variety of fluids. However, the hydrocyclones of
the present
invention can be particularly suited to de-sanding bitumen-containing aqueous
fluids such as
those having sand and/or gravel in a slurry of water, bitumen and solids. In
another specific
embodiment, the hydrocyclone can be used to de-sand bitumen-containing fluid
without aerating
the fluid before or during the processing to a large degree. Alternatively, in
some embodiments,
CA 02638550 2008-08-07
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a small amount of air can be entrained while forming the slurry. The entrained
air can attach to
the bitumen and cause it to become lighter than water and thus will result in
more effective
transfer of bitumen to the overflow. Under some conditions, an entrained air
slurry can require
less water washing in the hydrocyclone and/or result in lower amounts of
bitumen being lost to
the underflow. Further, in another embodiment, the processing of a bitumen-
containing fluid
through the hydrocyclone can remove about 50 to 90% of particulate in the form
of gravel and
sand, from the bitumen-containing fluid, although these amounts can vary
depending on
operating conditions and fluid properties.
In accordance with the above discussion, various embodiments and variations
are
provided herein which are applicable to each of the apparatus, fluid flow
patterns, and methods
of separating components of a fluid described herein. Thus, discussion of one
specific
embodiment is related to and provides support for this discussion in the
context of the other
related embodiments.
As a general outline, a hydrocyclone can include a substantially open
cylindrical vessel
with an open vessel inlet. The open vessel inlet can be configured to
introduce a fluid
tangentially into the open vessel. In a specific embodiment, the open vessel
inlet connecting the
helical confined path to the open vessel can be configured to introduce the
fluid with minimal
disturbance in fluid flow. The hydrocyclone can also include a helical
confined path connected
upstream of the open vessel at the open vessel inlet. An overflow outlet and
an underflow outlet
can be operatively attached to the open vessel. The underflow outlet can be
attached at a
location on the open vessel substantially opposite the helical confined path
and open vessel inlet.
The overflow outlet can terminate, on one end, at a vortex finder positioned
in an interior of the
open cylindrical vessel. The overflow outlet can further include a
substantially enclosed conduit
from the vortex finder to an exterior of the open cylindrical vessel. A wash
or rinse fluid can be
injected along either the helical confined path and/or within the open vessel
as described in more
detail below.
One embodiment of a hydrocyclone 2 in accordance with the present invention is
shown
in FIG. 1A including a helical confined path 4 connected to a substantially
open cylindrical
vessel 6 at an open vessel inlet (not shown). The hydrocyclone further
includes an underflow
outlet 8 attached to the open vessel substantially opposite the helical
confined path. The
CA 02638550 2008-08-07
-18-
underflow outlet illustrated is oriented to match the residual helical flow
within the open vessel
to facilitate removal of underflow fluids. In the case of FIG. 1A, the helical
confined path is on
the left or on the top of the hydrocyclone, the underflow outlet is oriented
on the opposite end of
the open vessel on the right or on the bottom of the open vessel. The
hydrocyclone further
includes an overflow outlet 10 attached to the open vessel. As shown in each
of FIGs. lA and
1B, the overflow outlet 10 terminates at one end with a vortex finder 12. The
vortex finder can
be positioned centrally within the open vessel 6 and can be further positioned
at a depth 14 that
is central. As shown in FIG. 1B, such depth can be adjusted based on the
particular fluid
velocity, composition and other variables to maximize separation of the
bitumen-rich portion
(overflow) and the particulate-rich portions (underflow). FIG. 1C illustrates
a top view end view
of FIGs. 1A and 1B. FIG. 1C shows the underflow outlet 8 and the winding
helical confined
path 4. Although not always required, as can be seen in FIG. 1C, outer
diameters of the helical
confined path and the open vessel 6 are substantially the same, at least where
these two members
are joined. FIGs. 1B and 1C also illustrate the slurry inlet 16 where the
fluid to be separated can
be fed into the hydrocyclone. Further, the figures show optional wash inlets
18, 20 and 22 which
allow injection of a rinse fluid to further enhance collection of bitumen from
sand and coarse
particulates. FIGs. lA and 1B show two wash inlets 18 and 20 configured to
inject wash fluid
tangentially into the path of the spiraling fluid within the open vessel. Such
inlets are obscured
in the top view (FIG. 1C) by the slurry inlet 16. Another optional wash inlet
22 is shown in the
figures and which is configured to direct fluid into the path of fluid flowing
in the helical
confined path. Most often, the wash water enters the helical confined path
tangentially in the
outer swirl region where most of the coarse solids congregate and travel as a
slower moving bed
than the bulk of the liquid due to centripetal action and thus wash or push
bitumen containing
water out of interstices between the coarse sand and particulates. Further,
although inlet 22 is
shown as being perpendicular to the helix, in most cases it is mounted in a
tangential direction in
line with and in co-direction with the helical path, similar to the mounting
of inlets 18 and 20 on
the open vessel. Normally several such inlets will be provided along the
helical path. The
velocity of the wash water must be such as to minimize disturbance of the
helical flow and is
thus typically lower than the average velocity of the fluid flowing in the
helix, since the solids
CA 02638550 2008-08-07
-19-
form a moving bed along the outer periphery of the helix and flow at a slower
velocity than the
average flow in the helix.
FIGs 1A through 1C are configured for co-current flow, as indicated by the
overflow
outlet attached in a position opposite the helical confined path and near the
underflow outlet. In
another alternative embodiment, FIGs. 2A through 2C illustrate a counter-
current flow
embodiment. In this case, the overflow outlet 24 is configured to remove
overflow from a
common end of the open vessel 6 as the helical confined path 4 and opposite
the underflow
outlet 8. As such, the vortex finder 26 is positioned a depth 28 into the open
vessel 6. This
depth can be again adjusted according to the particular operating conditions
for a given fluid or
slurry.
The helical confined path situated upstream of the open vessel can serve at
least three
purposes. First, it can be configured to cause a fluid to at least partially
separate, or begin the
separation process prior to entering the open vessel. Second, the helical
confined path can cause
the fluid to travel in a path that encourages further separation and easier
transition once
introduced into the open vessel. Third, wash water injected tangentially along
the outer
periphery of the helical path can replace bitumen, fines and water mixtures
out of interstitial
voids between coarse particulates traveling as a moving bed along the outer
periphery of the
helical confined path. As such, parameters such as the size and configuration
of the helical path,
the direction and location of wash water injection points along the helical
path, the dimensions of
the open vessel, and the open vessel inlet can affect processing. The number
of rotations of the
helical confined path can, for some fluids, allow for a shorter or longer time
spent in the open
vessel to produce the same level of separation. In a specific embodiment, the
helical confined
path can wind for about 2 to about 10 full rotations. In a further embodiment,
the helical
confined path can wind for about 3 to about 5 full rotations. The embodiments
illustrated in
FIGs 1A through 2C show three full rotations. One rotation is indicated at 30
in FIG. 2B. In
addition, the distance between successive rotations can be varied. A more
extended helical spiral
can result in a higher forward velocity upon entry into the open vessel. This
forward velocity
can be adjusted by varying the distance between successive rotations in the
helical path, among
other variables. As a non-limiting general guideline, the distance 30 between
successive
rotations can be from about 0.2 to about 4 times the outer diameter of the
helical path, and in
CA 02638550 2008-08-07
-20-
some cases from about 0.3 to about 1.5 times. The drawings show a helical path
of constant
curvature. However in some cases it is beneficial to configure the helical
path in the form of a
spiral of progressively increasing curvature until it reaches the open vessel.
The spiral may be in
one plane around (a compacted helical path) or near the open cylindrical
vessel or assume the
outline of a cone. Such a spiral provides for a gradual and progressive change
in curvature and
reduces the amount of disturbance as the contents flow from a pump or a
straight pipe into and
through the helical confined path and thence smoothly into the open
cylindrical vessel.
The helical confined path can also be formed in a variety of ways. For
example,
complementary structural channels can be rolled to the desired curvature and
joined. FIGs. 9-12
illustrate several such joined conduits having rectangular cross-sections.
FIG. 8 illustrates
complementary channels which can be rolled and then joined as shown to form an
enclosed fluid
pathway. FIG. 10 illustrates a similar arrangement including intermediate
joining members
between each of the complementary channels. FIG. 11 and FIG. 12 each show a
cross-sectional
area of a portion of respective conduits from FIG. 9 and FIG. 10 having
flanges oriented to
reinforce the joined channels. These flanges can be distributed along the
conduits every 4 to 12
inches, for example. Such flanges can be spaced to prevent or reduce bulging
of the channels
under internal pressure.
The open vessel inlet, which introduces fluid from the helical confined path
into the open
cylindrical vessel, can be configured to introduce the fluid with minimal
disturbance in the fluid
flow. For example, the internal surfaces at the connection between the helical
flow path and the
open vessel can be a substantially smooth transition where the outer diameter
of the helical flow
path blends into the inner surface contours of the open vessel. In one
embodiment, the outer
diameter of the helical flow path can be substantially identical to the inner
diameter of the open
vessel. In the interest of simplicity, FIGs. 1B, 1C, 2B and 2C the left wall
of the open vessel 6 is
illustrated as being a disc instead of a domed end wall most frequently used
for vessels under
pressure. Regardless, the fluid exiting the helical flow path can flow in a
swirl flow path within
the open vessel that initially is similar to the flow path in the helical
pipe. Minimal disturbance
in the fluid flow from the helical path to the open vessel allows for greater
separation efficiency.
This configuration further reduces abrasive wear on internal surfaces of the
open vessel. In
particular, initiating the swirl flow well ahead of introduction into the open
vessel can
CA 02638550 2008-08-07
-21-
significantly reduce wear and abrasion of the open vessel internal walls. The
slower flowing bed
of solids flowing along the outer periphery of the coil will flow into the
open vessel at a slower
rate than non-peripheral flow of the fluid. This aspect of the present
invention provides wear
reduction as compared with direct tangential introduction of a slurry into an
open vessel where
the swirl is established only after the slurry enters the open vessel.
To aid in fluid flow, in one embodiment, a pump or a plurality of pumps can be
used.
This is particularly useful at the beginning of the helical confined path to
cause the fluid to flow
at a desired velocity which is generally relatively high. Normally a pipe or
pipeline provides the
slurry to the helical path but pumps can optionally be additionally used.
However, care in design
should be taken in order to prevent or reduce undesirable disturbance to flow
patterns of the
incoming slurries.
In one aspect, the helical confined path can be a pipe. Such pipe can be
configured in a
helix symmetrically wound at a constant curvature or at progressively
increasing tight curvature.
In configurations using a pipe as at least a portion of the helical confined
path, the pipe can
include a plurality of pipe sections. In one aspect, one or a plurality of the
pipe sections can be
an elbow. In embodiments that incorporate a plurality of pipe sections,
including elbows, the
elbows can be of any angle that allows for the pipe to be in a helical
confined path. It can be
useful, depending on the type and size of pipe, to incorporate readily-
available pipe elbows. In
one embodiment, at least one elbow can be selected from 22.5 degree, 30
degree, 45 degree, or
90 degree elbows. In one design, more than one elbow can be used together to
form the desired
curvature of the helical confined path. In embodiments that include a
plurality of elbows, the
elbows can be substantially the same angle, or can include a plurality of
different angles. In a
detailed embodiment, such as in FIG. 4, the elbows 32 can each have a
substantially identical
bend angle. FIG. 4 illustrates a helical confined path, or section of a
helical confined path, that is
composed of a plurality of pipe elbows. The elbows are attached at flanged
joints 34. This
segmented helical path can facilitate cleaning, replacement, and other
maintenance.
In another embodiment, the helical confined path can be formed without pipe
sections
such as elbows. For example, a single length of pipe, tubing, or other
confining-material can be
created or formed to the desired helical shape. In the case of a pipe, such
shape can be achieved
by conventional pipe bending equipment or other suitable pipe shaping
techniques. In the case
CA 02638550 2008-08-07
-22-
of tubing or other readily movable material, the tubing can be wound into the
desired shape and
secured. These embodiments can be relatively inexpensive to make and install,
but may also
reduce access to internal sections for cleaning and/or maintenance.
One benefit of using a plurality of pipe sections to construct the helical
confined path is
that repair and replacement is relatively easy. For example, if a segment of
the pipe needs
replacing, it is a much simpler process to remove and replace the individual
pipe section than to
replace the entire pipe. Furthermore, as some maintenance of the pipe may
require access to the
inner channel of the pipe, it is generally simpler to detach or remove a pipe
section, and thus
have access to the inner area of the pipe, rather than insert tools and
equipment down the length
of the pipe, or to cut into a single pipe. In embodiments that include a
plurality of pipe sections,
the sections can be attached in any fashion that maintains that connection
during normal use for
the desired use time. However, care should be taken to maintain the same
curvature at and near
the joints as the curvature in the pipe sections in order to prevent the
creation of disturbances in
the flow. In a specific embodiment, at least one of the attachments can be
attachment by a
flanged joint. FIG. 4 shows flanged joints 34. Spacing flanged joints, as
opposed to welded
joints, periodically along the length of the helical confined path allows for
ease of repair of the
sections. Additionally, using flanged joints can allow for repair,
maintenance, or treating the
inner surface of the pipe. Further, relatively short flanged sections can be
preferred in some
embodiments, as they allow for easier repairs and/or maintenance as opposed to
larger sections
attached by flanged joints. Although flanged joints are discussed in
conjunction to pipes, it
should be noted that various optionally detachable joints can be used with a
variety of materials
used to create the helical confined path. When optionally detachable joints
are used, the same or
similar benefits can be realized as with flanged pipe joints, i.e. ease in
access to inside the
confined path, ease in repair, maintenance, etc.
One benefit of flanged joints, although not required, is in treating the inner
surface of the
helical confined path, e.g. pipe, and/or the open vessel. Some fluids can
include large particulate
solids, and even abrasive particulate, which can wear or otherwise alter at
least part of the inner
surface of the helical confined path and/or open vessel. Some fluids can
affect the inner surfaces
in other ways, such as corrosion and/or erosion. As such, it can be useful to
provide additional
wearing surfaces, particularly in the case of particulate solids in the fluid,
and to reinforce such
CA 02638550 2008-08-07
-23-
wearing surfaces to extend the working life of the surface, and thus the
hydrocyclone. Wearing
surfaces can include, but are not limited to, alloy hard surfacing, ceramic
coating, or the like.
Flanges are not required for the instant invention but can be preferred in
some embodiments,
since short flanged sections of the helical confined path and/or open vessel
allow repair of each
section after it has been abraded for a while by coarse solids flowing through
the hydrocyclone.
The use of flanges also makes it more convenient to hard plate, e.g. chrome
plate, the inside of
these sections individually to make it more wear resistant, or to hard surface
the inside of a at
least a portion of each section in those areas where the inside surface is
impacted by colliding
solids. Hard surfacing may be done by bead welding, overlay welding, bonding,
ceramic
deposition, build up, cladding, or by other suitable means. Such surfacing can
be uniform or
patterned, e.g. herringbone, dot, bead strings, waffle, etc. Rough surfaces on
the helical confined
path inside wall may create undesirable disturbance in the flowing liquid or
may create desirable
erratic movement of solids flowing along the wall to help dislodge trapped
bitumen particles.
Therefore, patterns welded on the inside wall of the helical confined conduit
need to be placed
carefully in those areas impacted mostly by the flowing solids in the conduit
an in the open
vessel.
Analysis of fluid flow, taking into consideration the composition of the fluid
and the
shape of the hydrocyclone, can indicate the potential wearing surfaces that
will experience the
most wear. For processing fluids with particulate solids, the wearing surfaces
of the helical
confined path may include the surfaces of the confined path on the more
circumferential point of
the helical path. As particulate solids may, in some cases, have a greater
density (or have larger
particle sizes), the circumferential action on the fluid traveling through the
pipe will cause the
particulate solids to migrate towards the portion of the path that is furthest
from a central axis of
the helical path. The fluid in the open vessel experiences similar forces, and
the majority of the
inner surface of the open vessel, depending on flow path, can experience
abrasive erosion.
These areas are more likely to experience abrasive erosion than more inside
sections, i.e. sections
closer to the central axis of the helical path. In the cases of corrosive
and/or erosive materials,
the wearing surface may include a majority of the inner surface of the open
vessel and/or the
helical confined path. As such, in one embodiment, at least a portion of an
inner surface of the
open vessel and/or the helical confined path can be reinforced as a wearing
surface. In a further
CA 02638550 2008-08-07
_
- -24-
embodiment, a majority of the inner surface of the open vessel and/or the
helical confined path
can be reinforced as a wearing surface.
In one embodiment, plating material onto the surface can reinforce the inner
surface of
open vessel and/or the helical confined path. The plated material preferably
has a greater
hardness than the hydrocyclone surface, or is more resistant, chemical or
otherwise, to fluid
action on the surface than the untreated inner surface. One of the materials
used to plate the
inner surface of an open vessel and/or a helical confined path can comprise or
consist essentially
of chrome, silicon carbide, titanium carbide or other hard materials suitable
for plating or
attachment to steel surfaces. Another manner of reinforcing a wearing surface
can include hard
surfacing the inner surface with welding tracks or beads. Other methods of
reinforcing a
wearing surface can include surface treatments, such as forming one or more
films on the
surface, and roughing or smoothing the surface. In a specific embodiment, at
least a portion of
an inner surface of the open vessel and/or the helical confined path includes
an anti-corrosive
material, for example rubber coating, urethane coating or epoxy coating.
In another embodiment, the helical confined path can be formed by wrapping a
flexible
hose into the shape of a coil that attaches to the open vessel inlet at the
hose outlet and attaches
to a pipe, pipeline or pump at the hose inlet. The hose can be made from any
suitable flexible
material such as, but not limited to, rubber, urethane or other durable and
wear and abrasion
resistant flexible material. The flexible hose can be reinforced internally in
the hose walls, for
example with steel mesh or steel wire. Such a hose may be relatively
inexpensive to form into a
helix or a spiral and will be easy to replace when worn out. The hose can be
readily wrapped on
a mandrel to keep it in shape or it could be fabricated to retain the form of
a coil or spiral. The
hose may be wrapped or fabricated to form a coil, a spiral in one plane or a
spiral that assumes
the outline of a cone as described previously.
The helical confined path length, much like the other parameters of the path,
can vary
greatly according to the composition of the fluid, desired processing, path
size and confmed path
composition. Likewise, the diameter of the vessel can vary greatly according
to the identified
factors. In one aspect, the helical confined path can have a flow diameter
(indicated as 16 on
FIG. 2A) of less than about 10 cm. Further, the helical confined path can have
a diameter of
greater than about 100 cm. The open vessel can have, for example, an average
diameter between
CA 02638550 2008-08-07
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the open vessel inlet and the vortex finder of less then 50 cm, although only
larger open vessels
are useful for most full-scale operations. In another embodiment, the open
vessel can have an
average diameter greater than about 1 meter, although sizes from about 200 cm
to about 15
meters may be useful. In yet another embodiment, the open vessel can have an
average diameter
of greater than about 10 meters The diameter of each of the helical confined
path and the open
vessel can vary in relation to one-another. For example, in one aspect, the
ratio of diameter of
the open vessel to the diameter of the confined path can be about 3:1 to about
10:1. In a specific
embodiment, the diameter of the open vessel to the diameter of the confined
path can be about
4:1. The diameter of the helical confined path, as used herein, should not be
confused with the
overall diameter of the helical confined path portion of the hydrocyclone. The
helical confined
path has a central axis around which the helical confined path rotates. The
overall diameter of
the helical confined path portion of the hydrocyclone can be defined as twice
the distance from
the central axis to an edge, wall, or curve, of the helical confined path
furthest from the central
axis. In one embodiment, the overall diameter of the helical confined path
portion of the
hydrocyclone can be approximately the same as the diameter of the open vessel.
In another
embodiment, the helical confined path portion of the hydrocyclone may be a
spiral with the outer
diameter of the spiral being several times the diameter of the open vessel.
However, these
dimensions can be adjusted so as to provide either a smaller or larger helical
flow path with
respect to the open vessel in some embodiments, provided these do not
introduce undesirable
flow disturbances.
In one aspect, the open vessel can have a diameter that remains substantially
uniform
from the connection of the helical confined path to the depth of the vortex
finder. In this case,
the noted portion of the open vessel has the shape of a cylinder. In a further
embodiment as
shown in FIGs. 3A and 3B, the diameter of the open vessel can decrease from
the depth of the
vortex finder 26 to the underflow outlet 8 so as to form a conical reduction
when the
hydrocyclone is configured for counter-current flow of the underflow with
respect to the
overflow.
Another factor to consider in creating or forming a hydrocyclone is the
material used to
form the vessel and/or helical path walls. Standard materials can be used in
the present
invention. Non-limiting examples include ceramic, metal and plastic or
internal covering of
CA 02638550 2008-08-07
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metal walls with ceramic, epoxy, plastic, rubber or other abrasion resistant
materials. In a
preferred embodiment, the hydrocyclone includes a metallic material. In a more
specific
embodiment, the vessel and helical confined path of the hydrocyclone can
comprise or consist
essentially of iron or its alloys such as steel, or steel that is coated with
an abrasion resistant
metal by means of plating or welding.
Processing various fluids can alter the physical properties of the fluid down
the length of
the helical confined path and/or the swirl path in the open vessel. In
separations of this nature, in
particular, it can be useful to introduce a wash fluid into the path of the
fluid in an outer location,
such that the wash fluid, having a lower density than at least a portion of
the fluid to be
separated, can travel through at least a portion of the fluid. Wash water
introduced at the proper
velocity tangentially into the moving solids bed of an oil sand slurry flowing
along the outer
periphery of the helical confined path can be made to push water containing
bitumen out of the
voids between particulates of the swirling stream and thereby transport
bitumen to the overflow.
The wash water velocity can typically be lower than the average velocity of
the stream in the
helical path since the solids flowing along the outer periphery of the helical
path represent a
moving bed of solids that flow at a lower velocity than the bulk velocity of
the stream in the
helix. The wash fluid traveling through the fluid to be separated thus serves
to encourage further
separation by freeing unseparated or trapped components.
As such, it is necessary in most cases to have one or more wash inlet
operatively attached
to the helical confined path. Wash inlet(s) also can be configured to
introduce wash fluid into
the fluid flow path within the open vessel. Likewise, the wash inlets on the
helical confined path
can introduce wash fluid into the path of the fluid traveling through the
helical confined path.
For example, the wash inlet can be in a central location in the wall of the
open vessel. In one
embodiment, a plurality of wash inlets can be attached tangentially to the
hydrocyclone. Various
configurations can be used, for example, one or a plurality of wash inlets
attached to the helical
confined path, with one or a plurality of wash inlets attached to the open
vessel. These wash
inlets can be oriented for direct injection or for tangential injection.
The inlet to the helical confined path is at one end of the helical confined
path and is the
primary source of introducing the fluid into the hydrocyclone. The fluid
travels through the
helical confined path and subsequently, the open vessel. Components of the
fluid are separated
CA 02638550 2008-08-07
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and removed through the underflow outlet and the overflow outlet.
As mentioned previously, the wash fluid can include a liquid such as water
and/or a gas.
One embodiment of a separating apparatus which is designed for a scavenging
wash gas in
accordance with the present invention is shown in FIG. 5 in a top plan view
and in FIG. 6 in side
view. The separating apparatus can include a helical confined path 101
connected to a substantially
open cylindrical vessel 102 at an open vessel inlet 103 which smoothly and
gradually connects to
the cylindrical portion 105 of the open vessel 102. Such smooth connection
allows for introduction
of the slurry with minimal disturbance in fluid flow. The separating apparatus
can further include
an underflow outlet 104 attached to a coned section 106 of the open vessel
102. In the case of FIG.
5, the helical confined path is in the form of a spiral that is connected at
its entrance 107 to a
straight supply pipe 108 with a flange 109. Additional flanges 110 are shown
in the drawings for
simplicity to be able to follow the path of the helical confined path.
As shown in FIG. 6, the separating apparatus can further include an overflow
outlet 111
attached to the open vessel 102 and ends with a flange 112 to allow for
connection to an overflow
pipe (not shown). The overflow 114 originates within the open vessel 102 with
a vortex finder 113
and ends with the outlet flange 112. Part of the overflow, which is shown with
dashed lines, is
located within the open vessel 102. The vortex finder 113 can be positioned
centrally within the
open vessel 102. The length of the overflow pipe 114 with its vortex finder
and can be fabricated to
allow the location of the vortex finder 113 at a most suitable depth in the
open vessel 102 to
maximize the efficient removal of overflow. The depth of the vortex finder 113
within the open
vessel 102 is optimized by trial and error or by fluid flow calculations for
the type of mixture to be
separated by the separating apparatus or hydrocyclone.
In accordance with the present invention, a gas can be injected through a
series of nozzles
along the helical conduit. A series of small nozzles are shown in FIG. 5 and
FIG. 6 as pointed
arrows 115 which are used to inject a stream of small gas bubbles into the
outer flow path of the
helical confined conduit 101 and of the open vessel 102. An example of a small
nozzle 116 is
shown schematically in FIG. 7 including a flow supply pipe 117 for the source
of the gas, and a
tiny gas nozzle outlet 118 that passes through the wall 119 of the helical
confined conduit 101 to
become a gas inlet to the conduit or to the open vessel along the outer
peripheral walls.
Similarly, the nozzle can be mounted on the wall of the open vessel, and be
configured to inject
gas through the wall of the open vessel.
The shape of the nozzle outlet 118 can be designed to achieve a high gas
velocity for the
gas entering through the wall of the conduit or of the open vessel. The
aperture size of the outlet
118 can be designed or adjusted to produce a desired bubble size and to
significantly increase
CA 02638550 2008-08-07
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contact area between the gas bubbles and slurry particles. More specifically,
a jet of gas passing
through a small nozzle at high velocity and entering a liquid stream along the
outer periphery has
a tendency to break up into a large number of very small gas bubbles,
especially when impacting
on solids in the liquid stream. When these gas bubbles encounter bitumen
droplets trapped
between coarse solids in the stream, these small bubbles have a tendency to
cling to the bitumen
droplets and cause them to assume a bulk density that is much lower than the
bulk density of the
stream of water and coarse solids flowing along the outer periphery of the
helical confined
conduit or along the periphery of the outer wall of the open vessel.
Centripetal forces acting on
the flowing liquid in the confined helical conduit or in the open vessel then
force the bitumen
droplets away from the outer wall of the helical confined conduit 1 due to
their reduced bulk
density in view of one or more small gas bubbles being attached to each
bitumen droplet.
This mechanism of bitumen scavenging is shown in more detail in FIG. 8, which
is a
simulated internal view of a section of the helical confined conduit 101.
Coarse and/or dense
solids 120 in a slurry flow along the outer wall 121 of the conduit due to the
centripetal forces
acting on the liquid flowing in a helical path through the conduit 101. Finer
and/or lighter solids
122 in the slurry flow closer to the centre of the conduit and very fine
solids (not shown) will
tend to flow along the inner periphery 123 of the conduit. The forces that
cause this sorting of
solids by size or density are the centripetal forces that act on the contained
fluid 124 flowing in
the curving conduit. A nozzle, illustrated with the arrow 125 and its supply
pipe 126 forces a gas
into the outer periphery of the flowing stream in the conduit to form small
gas bubbles 127 that
enter the flowing stream. Small bitumen droplets 128 trapped between the
coarse solids 120
attach themselves to gas bubbles upon contact and form bulk density reduced
bitumen droplets
129 because of their attachment to the gas bubbles. Centripetal forces acting
on the fluid of the
flowing stream force the bulk density reduced bitumen droplets to migrate
towards the inner
periphery 123 of the helical confined conduit and become part of the mixture
that eventually
reports to the overflow of the separating apparatus. In this manner, bitumen
can be scavenged
from the voids between the coarse particulates. The remaining bitumen depleted
coarse solids in
the slurry eventually report to the underflow of the open cylindrical vessel.
In this manner, the
underflow containing the coarse solids of the oil sand slurry become
relatively bitumen free and
the overflow will contain most of the bitumen particles of the oil sand
slurry. This mechanism of
CA 02638550 2013-02-28
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bitumen scavenging results in a higher overall bitumen recovery when the
overflow is
subsequently separated into bitumen, water and solids. Froth flotation can
optionally be
practiced on this overflow to recover the bitumen, however one aspect of this
instant
invention is for the recovery of bitumen by an oleophilic endless cable
screen, as per the
Kmyer process and/or in accordance with the previously noted related patent
applications.
A spiral helical confined conduit was chosen for the illustration of FIG. 5
and FIG. 6
since it lends itself particularly well for the smooth flow of a slurry in a
helical conduit. When
a serpentine pipe is used for the preparing of a slurry to disengage bitumen
from the oil sand
grains, the slurry undergoes very high mixing and shearing forces in order to
produce a well
digested slurry. Although beneficial in digestion of the slurry, a slurry
exposed to these high
mixing and shearing forces may also have a tendency to cause the
emulsification of some of the
bitumen particles with water in the aqueous phase of the slurry. In order to
at least partly break
this emulsion, a period of quiescence can allow the bitumen particles to de-
emulsify. A long,
large diameter, straight pipe between the serpentine pipe and the hydrocyclone
can be
beneficial for providing such a period of quiescence in the flowing slurry.
The specific length
can vary depending on the flow rates, degree of emulsification, and other
similar factors.
Using a helical confined conduit in the form of a spiral has the additional
advantage of
gradually increasing the centripetal force on the flowing slurry in the
conduit while keeping the
slurry in state of relative quiescence. A spiral is characterized by a
gradually increasing rate of
curvature. For a slurry flowing through such a conduit at a velocity that is
constant throughout
e centripetal force on the flowing slurry gradually increases and can become
very high as the
slurry moves towards the vessel. The centripetal forces of a slurry flowing
through a helical
confined conduit in the form of a spiral is the gradual movement of solids
towards the outer
wall. It should be noted that typically, a helical confined conduit has a
circular or otherwise
rounded cross-section, and the outer wall and inner wall are not necessarily
planar walls, but
are specific regions of the helical confined conduit. For example, the
curvature of the helical
confined conduit, at any point along the length, forms an arc that has a focus
point. The outer
wall is that
CA 02638550 2008-08-07
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region of the helical confined conduit that is farthest from the focus point,
whereas the inner wall
is that region of the helical confined conduit that is nearest the focus
point.
The centripetal forces of a slurry flowing through a helical confined conduit
has the
gradual movement of solids towards the outer wall with minimal disturbance of
the flowing
slurry. The coarse and heavy solids initially move to the outer wall, when the
centripetal forces
are relatively small, and then gradually, as the centripetal forces increase,
this layer of solids
increases in thickness as the smaller and lighter solids progressively deposit
onto the coarse
solids and into the voids between the coarse solids. In this manner, a
relatively smooth
transitional sorting of the solids takes place while the slurry is flowing
through the helical
confined conduit. After the slurry arrives in the open vessel, with a
transition having low
disturbance in fluid flow, the bed of coarse solids can continue to flow along
the outer periphery
of the open vessel and report to the underflow while the coarse solids
depleted slurry reports to
the overflow with most of the bitumen from the initial slurry.
The nozzles that supply gas to the helical confined conduit serve to introduce
gas bubbles
that effectively scavenge bitumen droplets out of the voids in the bed of
flowing solids flowing
along the outer wall of the conduit and helps in transferring these to the
stream that eventually
leave the hydrocyclone through the overflow. While this discussion mainly
centered around the
benefits of a helical confined conduit in the form of a spiral, a similar
transfer of captured
bitumen droplets takes place with the help of gas bubbles if these are
introduced in a helical
confined path in the form of a coil.
The nozzles can be present in a series along the length of the helical
confined coil. The
series can be regularly or irregularly spaced. Typically, a nozzle can be
mounted at a location
along the outer wall of the helical confined conduit. A variety of nozzles can
be used in the
design of the separating apparatus. In one aspect, the series of nozzles can
be designed for sonic
gas flow through the nozzles, where each nozzle is configured to produce local
cavitation and
gas dispersion upon the gas entry into the helical confined conduit
Gas bubbles may be produced in various sizes by the use of a nozzle impacting
on a
liquid. Small size gas bubbles are preferred for these have a lower tendency
to coalesce. A high
concentration of very small bubbles sweeping through the voids between coarse
particles near
the outer wall of the confined helical path has a greater opportunity to
dislodge bitumen from the
CA 02638550 2008-08-07
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voids than the same amount of gas in the form of larger bubbles. Generally,
bubbles can have
diameters smaller than about 3 mm, although bubbles having a diameter smaller
than about 0.3
mm or even about 0.03 mm can be particularly useful in achieving increased
contact surface area
with any trapped bitumen. While such small bubbles can be desirable there are
practical
limitations in the amount of energy that conveniently can be expended for
bubble formation and
bubble size reduction. Another method of producing very small and well
dispersed bubbles is to
prepare a liquid, such as, water and gas mixture under high pressure in a
vessel which is then
allowed to flow through the nozzles. Under high pressure, gasses such as air,
air enriched by
oxygen, methane, ethane, propane, carbon dioxide, or combinations thereof may
be dissolved in
large quantities in liquid, such as water, under high pressure. When such high
pressure liquid
and dissolved gasses flow through the nozzles of the instant invention and
encounter an
environment of lower pressure in the helical confined conduit, the gasses are
released in the form
of small bubbles. When the high pressure liquid of the instant invention
encounters the flowing
stream of liquid and particles in the helical confined conduit, many small
bubbles of gas are
released very quickly and sweep through the voids between the slurry solids to
transport trapped
bitumen out of the voids between the coarse solids.
Therefore, as outlined above, the instant invention can function to scavenge
bitumen droplets
out of the voids between coarse particulates in an oil sand slurry that report
to the underflow of an
open vessel of a separating apparatus. The scavenging can be accomplished by
means of small gas
bubbles produced by jets mounted in the outside curved wall of a helical
confined conduit of a
separating apparatus. In this scavenging apparatus and method, bitumen
droplets that are trapped in
the voids between coarse particulates are released by the action of the gas
bubbles which, by
adhesion to the bitumen droplets cause the bitumen droplets become lighter and
flow out of the
voids due to centripetal forces in the fluid flowing through the helical
confined conduit.
The gas used is a gas under pressure flowing through the nozzles and may
contain air,
oxygen enriched air, a light hydrocarbon gas, such as methane, ethane,
propane, butane, carbon
dioxide, or any combination thereof. The use of carbon dioxide may also serve
to neutralize an oil
sand slurry if it has a pH greater than 7. A neutral pH of about 7 can be used
for isoelectric
separation of oil sands to minimize the dispersion of tailings fines produced
during the subsequent
recovery of bitumen from the hydrocyclone overflow.
Optionally, one or more nozzle can be mounted along the wall of the open
vessel. Such
nozzles can be configured to inject a gas, a liquid including dissolved gas,
or even washing fluid.
The helical confined conduit situated upstream of the open vessel can be
configured to
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cause a fluid to at least partially separate, or begin the separation process
prior to entering the
open vessel. Additionally, the helical confined path can cause the fluid to
travel in a path that
encourages further separation and easier transition once introduced into the
open vessel. As
such, parameters such as the size and configuration of the helical confined
conduit, the number
and location of nozzles, the dimensions of the open vessel, and the open
vessel inlet can affect
processing. The number of rotations of the helical confined path can, for some
fluids, allow for a
shorter or longer time spent in the open vessel to produce the same level of
separation. In a
specific embodiment, the helical confined path can wind for about 1 to about
10 full rotations.
In a further embodiment, the helical confined path can wind for about 2 to
about 5 full rotations.
The open vessel inlet, which introduces fluid from the helical confined
conduit into the
open cylindrical vessel, can be configured to introduce the fluid with minimal
disturbance in the
fluid flow. For example, the internal surfaces at the connection between the
helical flow conduit
and the open vessel can be a substantially smooth transition where the outer
diameter of the
helical flow path blends into the inner surface contours of the open vessel.
In one embodiment,
the outer diameter of the helical flow conduit can be substantially identical
to the inner diameter
of the open vessel. The fluid exiting the helical flow path can flow in a
swirl flow path within
the open vessel that initially is similar to the flow path in the helical
pipe. Minimal disturbance
in the fluid flow from the helical confined conduit to the open vessel allows
for greater
separation efficiency. This configuration further reduces abrasive wear on
internal surfaces of
the open vessel. In particular, initiating the swirl flow well ahead of
introduction into the open
vessel can significantly reduce wear and abrasion of the open vessel internal
walls. The slower
flowing bed of solids flowing along the outer wall of the helical confined
conduit will flow into
the open vessel at a slower rate than non-peripheral flow of the fluid. This
aspect of the present
invention provides wear reduction as compared with direct tangential
introduction of a slurry
into an open vessel where the swirl is established only after the slurry
enters the open vessel.
To aid in fluid flow, in one embodiment, a pump or a plurality of pumps can be
used.
This is particularly useful at the beginning of the helical confined conduit
to cause the fluid to
flow at a desired velocity which is generally relatively high. Normally a pipe
or pipeline
provides the slurry to the helical path but pumps can optionally be
additionally used. However,
CA 02638550 2008-08-07
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care in design should be taken in order to prevent or reduce undesirable
disturbance to flow
patterns of the incoming slurries.
In a specific embodiment, a method for separating components from a fluid can
include
guiding the fluid along a helical path at a high velocity to form a helically
flowing fluid. The
method can further include tangentially injecting the helically flowing fluid
into an open vessel
such that the fluid rotates along a swirl path within the open vessel. The
fluid rotation in the
swirl path, and enhanced by rotation in the helical path, can be sufficient to
produce an overflow
and an underflow. Such fluid separation is based on the varying densities and
varying particle
sizes of the components of the fluid. The method can additionally include
injecting a rinse fluid
into at least one of the helical path and the swirl path. The overflow and
underflow can be
removed from the open vessel.
The fluid in the helical path can travel at any velocity sufficient to produce
an initial
separation of the fluid components while in the helical path and/or produce an
overflow and
underflow while in the open vessel. Such initial separation can include
compositional
differences across a diameter of flow. Although such velocity will vary
depending on the design
of the hydrocyclone and the fluid to be processed, in one embodiment, the
magnitude of the
velocity of the fluid in the helical path can be from about 1 meter per second
to about 10 meters
per second, and in some cases from about 2 meters per second to about 4 meters
per second.
In a specific embodiment, rinse fluid can be injected into the helical path
substantially
prior to the tangentially injecting into the open vessel. For example, rinse
fluid can be injected
along the outer periphery of the helical path at a central location along the
helical path between a
fluid inlet to the helical path and the open vessel inlet. Such injection
along the helical path can
include injection of a rinse fluid at a plurality of locations along the
helical path. Alternative to,
or in conjunction with injecting rinse fluid into the helical path, rinse
fluid of the same or
different type, can be injected into the swirl path. Such injection of rinse
fluid into the swirl path
can be substantially subsequent to the tangentially injecting. For example,
the rinse fluid can be
injected at central locations to the open vessel inlet and the underflow
outlet. As with injecting
rinse fluid into the helical path, rinse fluid can be injected into the swirl
path at a plurality of
locations. In a non-limiting example, the rinse fluid can comprise or consist
essentially of fresh
water or recycled water containing a small amount of fine solids and bitumen.
CA 02638550 2008-08-07
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The overflow and underflow will generally contain particulates but will have
different
compositions. The overflow will contain, ideally, water and bitumen and sand,
silt and clay
particulates which are smaller and possibly with lower density. The underflow,
on the other
hand, will ideally contain water, silt, sand, and particulates which are
larger and possibly having
a higher density. In one embodiment, the fluid to be separated can be a slurry
containing
particulates. In such case, and depending on the other components in the
fluid, the underflow
can include particulates. The hydrocyclones of the present invention are
particularly suited to
separation of an oil sand slurry which is a continuous water phase containing
dispersed bitumen
particulates or agglomerates, gravel, sand, silt and clay or a water
suspension of dispersed
bitumen product and fines. Alternatively, coal or other ore slurries can be
effectively separated
using the hydrocyclones described herein. In some alternate cases the fluid
may be air or gas
containing particulate or other matter which is separated by the hydrocyclone
of the instant
invention.
One specific use of the hydrocyclone can be in de-sanding fluids containing
bitumen. In
such case, the fluid can include particulates, bitumen, air and water.
Particulates included in the
bitumen-containing fluid can include gravel, sand, and fines. When processed,
the overflow can
include the majority of the bitumen of the fluid and the underflow can include
the majority of the
gravel and sand. In a specific embodiment, the overflow can include less than
20% of the
particulates in the form of sand and fines.
Not all bitumen-containing fluids are the same, and the varying properties of
the
bitumen-containing fluid can be considered when designing a particular
hydrocyclone.
Conditions and/or design of the hydrocyclone can be specifically configured
for improved and
optimum processing. In a specific embodiment, the helical path and/or open
vessel can be
designed and shaped based on compositional and physical properties of the
fluid. Therefore,
parameters may be adjusted for varying types of bitumen-containing fluids.
The bitumen-containing fluid can be a result of pre-conditioning of oil sands
and water.
As such, the composition of the fluid can, at least partially, depend on the
composition of the oil
sands. Some oil sands contain a high percentage of bitumen and low percentage
of fines, while
other oil sands contain moderate or a small percentage of bitumen and further
have a high fines
content. Some oil sands come from a marine deposit and other oil sands come
from a delta
CA 02638550 2008-08-07
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deposit, each having different characteristics. Some oil sands are chemically
neutral by nature
and other oil sands contain salts and other chemicals that affect, among other
things, the pH or
the salinity of the slurry.
Other factors to consider when dealing with oil sands include the composition
of the
rocks and gravel, and lumps of clay in the oil sand after crushing. Not only
the size of the rocks,
gravel and clay lumps but also the percentage of these in the crushed oil
sand, as well as the
shape of the rocks gravel or lumps of clay can affect processing conditions.
Likewise, the
chemical composition of the slurry as it is being processed by the
hydrocyclone can affect
processing. For example, a fluid that has a low pH or a high pH inherently, or
by the addition of
chemicals will have a very different rheological characteristic than a slurry
that is close to neutral
or close to the isoelectric point. The pH of a fluid can have a substantial
impact upon the
dispersion of fines in such a fluid and upon the resulting viscosity of the
fluid. At high or low
pH the clay fines are dispersed, resulting in low viscosity fluids in which
bitumen particles and
the coarse solids are substantially free to move and/or settle within the
fluid.
A factor to consider in selecting processing parameters is the velocity of the
fluid as it
flows through the hydrocyclone, and helical confined path in particular. For a
given pump
capacity, a different pipe size will result in a different fluid velocity in
the hydrocyclone.
Therefore, multiple pumps can be used in some embodiments ahead of the helix
(rather than in
or after the helix which would create undesirable disturbance to the flow
path).
Processing time for fluids differs greatly depending on the helical confined
path, open
cylindrical vessel, fluid, desired processing, etc. As a non-limiting example,
however, the fluid
can have an average residence time in the hydrocyclone, from introduction into
the helical
confined path, until removal as either underflow or overflow of from about 1
second to about 30
seconds, and in some cases from about 4 seconds to about 10 seconds.
Therefore, as outlined above, the instant invention can function to separate
components
of fluids. These fluids may use water, hydrocarbons, gasses or air as the
conveying media. The
present invention can effectively process, at least partially, fluids
containing bitumen and
particulate in a manner that may not require the addition of hazardous
substances, or gasses to be
entrained in the fluid and later removed, and the processing may not produce
hazardous, toxic, or
dangerous by-product streams. Additionally, the combination of a helical
confined path and
CA 02638550 2008-08-07
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open vessel gives greater control over separation and fluid flow than does
separation by means of
one or the other portions of the hydrocyclone alone.
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.
