CA2700446A1 - Speed of separation - mine face oil sand extraction - Google Patents

Abstract

Methods and equipment are disclosed and claimed for rapidly producing a slurry from oil sand ore and water, and for rapidly separating the resulting oil sand slurry at a location potentially closer to the mine face than practiced in prior oil sands art. The oil sand slurry is produced in a cateracting slurry drum generally in less than 2 minutes and contains approximately 58% solids and very little air. After oversize removal this slurry is agglomerated and separated by means of a rugged revolving apertured oleophilic screen in about 10 minutes, yielding high bitumen recovery. The effluent tailings are continuously dewatered and the produced water and its contained fines are returned to the process. During dewatering, fines are captured interstitially in the voids of the solid tailings. The solid tailings may be used for site remediation, potentially without the need for long duration storage at conventional tailings ponds.
The oleophilic screen was found to be very tolerant of fines in the recycle water.

Description

Jan Kruyer, P.Eng. Thorsby, AB.
SPEED OF SEPARATION - MINE FACE OIL SAND
EXTRACTION.
RELATED APPLICATIONS

This application is related to Canadian Patent Application number 2,661,579 filed April 9th, 2009 entitled " Helical Conduit Hydrocyclone Methods, number 2,638,551 filed August 7th , 2008 entitled "Sinusoidal Mixing and Shearing Apparatus and Associated Methods ", number 2,638,596 filed August 6tt', 2008 entitled "Endless Cable System and Associated Methods ", number 2,666,025 filed May 19th, 2009 entitled "Pond Sludge Bitumen and Ultra Fines Agglomeration and Recovery ",and number 2,690,951 filed January 27th, 2010 entitled `Endless Cable BeltfllignmentApparatus and Methodsfor Separations".
RELATED PATENTS

Reference is also made to Canadian patent 918,588 entitled "Hot Water Process Conditioning Drum " granted to Marshall et. al. on January 9th, 1973, to Canadian patent 1,141,318 entitled "Conditioning Drum for Slurries and Emulsions"
granted to the present inventor on February 15th, 1983, to Canadian patent 2,029,795 entitled "Pipeline Conditioning Process for Mined Oil-Sand" granted to George J.
Cymerman November 5th, 1996, and to 1,232,854 entitled "Use of a Submersible viscometer .... Hot Water Process... " granted to Laurier L. Schramm April 16th, 1988 FIELD OF THE INVENTION

The present invention relates to methods for rapidly separating oil sand ore, potentially close to an oil sand mine face, using an apertured oleophilic screen to capture bitumen from oil sand slurry on surfaces of the screen but to allow de-bituminized aqueous phase of the slurry to pass to disposal through apertures of the Jan Kruyer, P.Eng. Thorsby, AB.
screen. Accordingly, the present invention involves the fields of process engineering, chemistry, physical chemistry and chemical engineering.

BACKGROUND OF THE INVENTION
In the present invention a revolving apertured oleophilic screen, preferably in the form of closely spaced endless cable wraps is used to separate an oil sand slurry produced from crushed oil sand ore mixed with water. A number of Canadian patents pending for the present inventor describe in detail the construction of and methods for the use of apertured oleophilic screens to achieve separations. In separation zones bitumen is captured by the screen surfaces whilst de-bituminized slurry or mixture passes to disposal through the screen apertures. In bitumen recovery zones, bitumen, is stripped from the screen surfacess by various methods, such as for example, are described in granted and copending Canadian patent applications, some of which also are pending in the U.S. or have been granted there. Many types of separation zones and many types of bitumen removal zones have been described by the inventor in the above referenced patent applications. The present invention makes use of the fact that separating oil sand slurry by means of an oleophilic apertured screen is about ten times as fast as separating oil sand slurry by the conventional method of bitumen froth flotation. When a process is ten times as fast, the equipment needed to achieve that separation can be much smaller and more economically viable. It opens the possibility of moving the separation equipment as the oil sand mine face recedes, and the mining and ore transporting equipment follows the receding mine face.
The specifications of the above referenced prior patents and of the presently pending applications provide extensive details as to the size and composition of the Alberta oil sands resource. Those specifications also describe various methods used for separations that use revolving oleophilic apertured screens and provide details on the chemistry of oil sands separation. For that reason, reference is made hereby to disclosures detailed in these referenced patents and applications. For the sake of brevity, these details are not repeated here, except when these apply specifically to the present invention.

Jan Kruyer, P.Eng. Thorsby, AB.
HIGH SPEED CATERACTING DRUMS

The present invention discloses a unique method of using a high speed rotating cateracting drum to rapidly produce a dilute slurry of crushed mined oil sand and water that is suitable for separation by a revolving apertured oleophilic screen after oversize material has been removed from the slurry by grizzly and/or hydrocyclone. The drum is operated in cateracting mode and does require the use of steam sparging to prepare a slurry for separation. As a potentially alternate method of slurry preparation the present invention makes use of highly turbulent flow in a serpentine pipe described in Canadian patent application 2,638,551. Again, oversize is removed from the slurry by means of a hydrocyclone before separation. One hydrocyclone specifically designed for that purpose is disclosed in Canadian patent application 2,661,579.

Current commercial oil sand separation plants use two methods for preparing oil sand slurries. In the most recently built commercial plants, the oil sand ore is crushed by means of roller crushers and then is mixed with hot or warm water containing a process aid such as, for example, sodium hydroxide. This mixture is pumped through a generally straight pipeline in turbulent flow, in the presence of air and process aid, to disengage oil sand bitumen from sand grains of the oil sand ore and to form a thick aerated slurry that is suitable for separation by bitumen froth flotation after it is flooded with dilution water. Such a pipeline slurry, before flood water is added, may contain by weight 70.4% solids, 20.5% water and 9.1%
bitumen.
Its water content is kept low on purpose to encourage the entrainment of air in the slurry before flood water is added. After the flood water is added, the released and dispersed air bubbles are free to help bitumen rise to the top of separation vessels by froth flotation in the thin slurry. Air is supplied at the entrance of the slurry pipeline and may also be added to the thick slurry as it flows through the pipeline.
After flood water is added, the slurry flows into separation vessels where aerated bitumen rises to the top and is skimmed off. The composition by weight of flooded slurry may then be 50% solids, 43% water and 7% bitumen. The above and below information about Jan Kruyer, P.Eng. Thorsby, AB.
conventional oil sands plants is readily obtainable from a review of the prior art found in published literature and in patents open to the public.
In contrast to oil sand slurry production by means of a pipeline, commercial oil sands plants that were build some years ago, make use of slowly rating conditioning drums in which the oil sand and water mixture tumbles in the drum in gently mixing or cascading mode to produce a thick oil sand slurry that may contain by weight 68.3% solids, 22.8% water and 8.9% bitumen. Steam enters such a drum through sparging valves feeding perforated steam ducts mounted along the internal periphery of those drums, sparge steam into the slurry. The composition of the slurry produced in these drums is very similar to that of the thick slurry produced by an oil sand slurry pipeline. Of coarse, commercial oil sand slurry will vary with the type or composition of the oil sand ore being processed.
A commercial conditioning drum typically is 5.5 meters in diameter, 30.5 meters long and revolves at about 3 RPM. The critical speed of a drum of that size is 18 RPM, indicating that these commercial conditioning drums rotate at about 17% of their critical speed. This drum rotation speed results in cascading of the contents inside the drum, but does not normally provide for cateracting of the oil sand drum contents. These drums are not designed to operate in cateracting mode. Gentle mixing of oil sand ore with water and air to conditioning it and form a thick slurry at elevated temperature for subsequent separation by bitumen froth flotation is the objective of these conditioning drums.
For current commercial oil sands plants, process water used for producing oil sand slurry must be low in dispersed solid content to achieve acceptable bitumen recovery since fines tend to interfere with the efficiency of froth flotation.
This applies to water used to produce un-flooded oil sand slurry and also applies to the dilution water used to flood the slurry before separation. That is the reason why recycle water used for the current commercial plants is taken from the very top of its tailings ponds where most of the solids have settled for years to lower levels in the ponds.
The present invention discloses a method for producing a slurry that is suitable for separation by a revolving oleophilic apertured screen. For effective Jan Kruyer, P.Eng. Thorsby, AB.
separation, this screen requires a slurry that is thinner than the thick aerated slurry currently produced commercially by pipeline or by a slowly turning conventional conditioning drum, but that may be thicker than the conventional thin slurry, flooded by water to make it suitable for separation by bitumen froth flotation. The desired slurry for oleophilic screen separation does not contain any significant amounts of air and may be produced by means of a serpentine pipe disclosed in patent application 2,638,596 or may be produced by a rapidly turning slurry drum operating in cateracting mode as disclosed in the present invention. This slurry drum is provided with crushed oil sand at ambient temperature and warm or hot water is added to produce a slurry with an average temperature, somewhere between 20 and 50 degrees centigrade depending on oil sand composition and apparatus configuration. The required temperature of the added water is a function of the season and of the temperature and frozen or unfrozen nature of the mined oil sand ore. Unlike conventional oil sand conditioning drums, the cateracting slurry preparation drum of the present invention does not have any provision for injecting steam into the drum or into the slurry but, in addition to turning faster, may be provided with longetudinal lifters mounted along the drum interior cylindrical wall to encourage cateracting of its contents at drum rotational speeds higher than conventional conditioning drums. The produced slurry contains by weight between 65% and 55% solids and between 25%
and 40% water, and the drum rotates at between 30% and 80% of its critical speed (i.e. RPM). The cateracting contents of the drum creates a high degree of turbulence in the drum interior, causing rapid conversion of mined oil sand and water into an oil sand slurry. Cateracting drum rotating at those speeds can producing an un-aerated dilute slurry much faster than current commercial slurry tumbling drums that turn at about 17% of critical speed and produce a thick aerated slurry. The current commercial drums require a residence time of about 3 or 4 minutes. The drum of the present invention can be much smaller for producing the same amount of slurry per hour and requires a residence time for slurry production of less than 2 minutes and less than lminute in some cases. Hardened teeth may be mounted inside the drum to break up cascading lumps of oil sand ore to speed up the ablation process. In the Jan Kruyer, P.Eng. Thorsby, AB.
present invention, neither steam nor air are needed in the drum to produce a slurry for subsequent separation by a revolving apertured oleophilic screen.
A unique feature of the present invention is that the equipment required to separate an oil sand slurry by sieving is about one tenth to one twentieth the required size of conventional equipment for separating an oil sand slurry by froth flotation.
The resulting size reduction in required equipment, both for slurry production and for slurry separation may make it possible to move the complete separation plant continuously with the receding mine face, or from time to time as required, and thus keep it in close proximity to the mining equipment that moves with the mine face.
Such a dramatic and unexpected change in plant size and configuration will have a major and beneficial impact on the cost of future mined oil sands plants; both in capital cost and also in operating cost, including the cost of materials handling.
Thus, to summarize slurry production, the present invention produces a slurry from mined oil sand; a slurry that generally has a composition of intermediate solids content as compared with the slurries currently prepared for commercial oil sand separation. It contains between 65% and 50% solids by weight. The slurry has a solids content and a water content that is between the conventional thick aerated slurry and the conventional flooded slurry of the current commercial oil sands plants.
To produce thick aerated slurry, the conventional commercial plants use a pipeline to mix the ore with water and air in turbulent flow or use very large conditioning drums, rotating in cascading mode, with a length to diameter ratio of greater than 5 at a rate of rotation less than 18% of critical speed and gently mix the ore with water and air, and/or with steam that is sparged into the drum contents to produce thick warm aerated slurry. The thick aerated slurry of the current commercial plants, containing about 68% solids, is flooded with water, to reduce its solids content to about 50%
before it enters the froth flotation separation vessels. In contrast, an object of the present invention is that the slurry must cateract inside the slurry preparation drum for fast ablation. It does not flow to a froth flotation vessel but may pass trough a grizzly and/or hydrocyclone to remove oversize material that may hinder the effective separation of this slurry of interemediate composition by a revolving apertured oleophilic screen or may abrade the screen. Before separation, it is first agglomerated Jan Kruyer, P.Eng. Thorsby, AB.
to increase bitumen particle size after which it flows to an apertured oleophilic screen for separation.
Sparging steam is not used in the present invention but warm or hot water are used to produce a slurry, year round, that has a temperature below 50 centigrade.

Since air entrainment in the slurry is not desired, the slurry can be made rapidly in drums that rotate at high RPM, in excess of 30% of the critical drum speed, and preferably at higher rotational speeds unless excessive stresses on the drum structure:
limit the drum speed. Hardened teeth may be mounted inside the drum to help break up cascading large oil sand lumps. Rocks and gravel of the oil sand ore cascading in the drum also serve to break up oil sand lumps. Since the temperature of the produced slurry of the present invention can be lower than the temperature of conventional slurry of the prior art, steam is not required in the slurry preparation drum of the present invention.
Since, unlike froth flotation, separation of oil sand slurry by an apertured oleophilic screen is very tolerant of the fines in the process water, tailings run off water may be recycled while still warm. That means, water used for making slurry in the present invention may use hot water in combination with oil sand tailings pond water or with warm or lukewarm tailings run off water.
In addition to deviating from the conventional practice of mined oil sand slurry production, the present invention also reduces in a major way the size of the separating equipment by using bitumen agglomeration and screening that is generally an order of magnitude faster than froth flotation. For flotation the aerated bitumen has to struggle in its upward movement against settling sand and fines in aqueous suspension in tall and large diameter separation vessels. The rising bitumen takes a long time to rise to the top of the separation vessels. However, the cost of commercial froth flotation equipment does not allow major extensions of the extraction plant residence time. That is the reason why bitumen mats float on top of the current tailings ponds, since in the ponds the very fine bitumen particles have adequate time to rise to the top. Unfortunately, these floating bitumen mats have resulted in the death of may birds landing on these mats. This currently this is the topic of a major court case Jan Kruyer, P.Eng. Thorsby, AB.
For oleophilic sieving, the slurry passes through a revolving apertured oleophilic screen to separate the contained bitumen from the aqueous phase of the slurry. Prior bitumen agglomeration serves to increase bitumen particle size to increase the effectiveness of bitumen capture by the oleophilic screen surfaces. Pilot plant test have shown that screening bitumen can capture more bitumen from oil sand slurry than froth flotation, and do it faster. Faster processing allows a reduction in the required size of commercial equipment and this is bound to make oil sand separation less expensive. Small equipment also is easier and cheaper to move than large equipment.
Smaller equipment size does not necessarily mean a reduction in the diameter of the slurry preparation drums but mostly means a reduction in the length of the drum. Thus, for example a 5 meter diameter 30 meter long drum may be reduced to a 5 meter diameter, 5 meter long drum to achieve a reduction in equipment size of a factor of 6.
However reducing the drum diameter from 5.5 meter to 2.2 meter, while keeping it 30 meters long to achieve the same reduction in equipment size normally is not an option. Reducing drum cross sectional area for speeding up slurry production is less effective than reducing the drum length. For that reason cateracting drums of the present invention preferably are larger than 3 meters in diameter and more preferably larger than 5 meters in diameter, but are much shorter than 30.5 meters. The turbulence created in the drum by cateracting is much greater for large-diameter drums than for small diameter drums, since the cateracting charge falls through a greater distance when the drum diameter is larger, adds more energy to the slurry and breaks it up faster.
Cateracting drums of the present invention generally are horizontally mounted but may be mounted at a decline that is less than 5 degrees between entrance and exit to improve flow of slurry to the exit. In that case, proper support of and alignment with slewing rings is required to keep the drum properly and efficiently supported to reduce wear of the slewing rings and rotating ring supports. Instead of slewing rings and rollers, inflated rubber tires may be used to support the drum, provided that the drum circumference is not deformed by the weight of the drum and its contents.

Jan Kruyer, P.Eng. Thorsby, AB.
BRIEF DESCRIPTION OF THE FIGURES

Figure 1 is a flow diagram of a current commercial oil sand separation process using bitumen froth flotation.
Figure 2 is a flow diagram of a proposed oil sands separation process that uses a serpentine pipe to produce an oil sand slurry and an apertured oleophilic screen (oleophilic sieve) to separate the slurry. It may be located close to a mine face and by that location may eliminate the long pipeline of Figure 1. An optional tailings dewatering conveyor is included in the Figure Figure 3 is a flow diagram of a proposed oil sands separation process that uses a cascading slurry preparation drum. It is very similar to the flow diagram of Figure 2 but replaces the serpentine pipe with a cascading conditioning drum and the dewatering conveyor with optional stationary tailings dewatering.
Figure 4a is an isometric drawing of a cateracting drum of the present invention for producing an oil sand slurry.
Figure 4b is inside view of the drum of Figure 4a through section A-A of Figure 4a DEFINITIONS
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 the 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.
In describing and claiming the present invention, the following terminology will be used in accordance with the definitions set forth below. When reference is Jan Kruyer, P.Eng. Thorsby, AB.
made to a given terminology in several definitions, these references should be considered to augment or support each other or shed additional light.
"ablation" refers to the disengaging of bitumen from sand grains of oil sand ore in the presence of warm water. It normally occurs in a revolving drum or in a pipeline in turbulent flow and results in the production of oil sand slurry.
Conditioning is another term for ablation but conditioning normally includes the use of a process aid, such as sodium hydroxide, to disperse clay fractions of the oil sand ore and to react with naphthenic acids of the oil sand ore to form detergents.
Ablation does not necessarily involve sodium hydroxide or process aid additions to produce a slurry.
"agglomeration" refers to increasing the size of bitumen particles in an aqueous mixture prior to the removal of enlarged bitumen particles from the mixture by an oleophilic apertured wall or screen . Agglomeration may be accomplished in a revolving drum that contains oleophilic surfaces. For example, the apertured walls of the agglomerator of Figures 2 and 3 may be oleophilic, or oleophilic baffles or oleophilic tower packings inside the agglomerator may provide surfaces for capturing dispersed bitumen phase from a slurry to increase the size of the bitumen particles by mutual adhesion, before these are sloughed off in the form of bitumen of increased particle size due to drum rotation, and flow to the revolving apertured oleophilic screen surrounding the apertured drum wall of the agglomerator. Alternately the agglomerator may contain a bed of tumbling oleophilic balls that capture dispersed bitumen particles from the slurry and release enlarged bitumen phase particles thereafter. During pilot plant studies, it was noted with agglomerating drums, such as shown in Figures 2 and 3 rotating in counter clockwise direction, that most of the bitumen phase flowed to the surrounding apertured oleophic screen or belt through the right bottom quadrant of the cylindrical drum, while most of the de-butuminized aqueous phase flowed to the surounding apertured belt through the left bottom quadrant of the drum. Copending patent applications of the present inventor provide additional details for the construction and operation of bitumen aglomerators that support an apertured belt. Another alternate method, that I have used, to provide for a lesser degree of bitumen agglomeration makes use of rotating blades in a vessel filled Jan Kruyer, P.Eng. Thorsby, AB.
with slurry. In that case, bitumen particles of the slurry, revolving in the stationary vessel, come in contact with other bitumen particles of the slurry and adhere to each other to form enlarged bitumen phase particles floating in the slurry.
"apertured agglomeration drum" refers to a rotatable drum that contains oleophilic surfaces inside the drum and is provided with an apertured cylindrical wall that allows agglomerated mixture to flow to the partly surrounding oleophilic screen to capture bitumen. An agglomerator drum is used to increase the particle size of bitumen particles in oil sand mixtures prior to separation. The drum may contain interior oleophilic baffles or a bed of tumbling oleophilic balls. An agglomeration drum does not operate in cateracting mode, but rather in cascading mode well below 30% of critical drum speed.
"bitumen" refers to a viscous hydrocarbon that contains maltenes and asphaltenes and is found originally in oil sand ore interstitially between sand grains.
Maltenes generally represent the liquid portion of bitumen in which asphaltenes of extremely small size are thought to be dissolved or dispersed. Asphaltenes contain the bulk of the metals found in bitumen and probably give bitumen its high viscosity.
"bitumen phase" normally refers to small bitumen droplets that have been agglomerated into enlarged bitumen drops or streamers. Bitumen streamers are enlarged bitumen masses that can flow as distinct units in the presence of aqueous phase. Another example of bitumen streamers are the bitumen mats found at various levels in oil sand tailings ponds or the bitumen mats that often are found to float on the surface of oil sand tailings ponds. However these bitumen mats are much larger than the bitumen streamers that flow from an agglomerator interior to an apertured oleophilic screen.
"bitumen recovery" or "bitumen recovery yield" refers to the percentage of bitumen removed from an original mixture or composition. Therefore, in a simplified example, a 100 kg mixture containing 45 kg of water and 40 kg of bitumen where kg of bitumen out of the 40 kg is removed, the bitumen recovery or recovery yield would be a 95%.
"cable wraps" refers to multiple wraps of endless rope or cable wrapped around two or more rollers or drums where the spaces between sequential cable wraps Jan Kruyer, P.Eng. Thorsby, AB.
form apertures through which aqueous phase can pass, giving up some or most of its bitumen content to the wraps as bitumen phase passes by and contacts the wraps.
Alternately it refers to adjacent single endless ropes or cables in contact with supporting rollers or drums. An endless cable may have multiple wraps or multiple single endless cables may be placed next to each other to form a sieve whereby aqueous mixture can pass between the cable wraps and bitumen may be captured by the wraps.
"cateracting slurry" refers an oil sand slurry inside a slurry preparation drum that rotates fast enough that some of the slurry containing lumps of oil sand, rocks and gravel are lifted away from the main slurry bed in the drum and fall back down into the slurry bed. When a slurry drum rotates at about 20 percent of critical speed, the slurry bed represents a tumbling bed in which the slurry tumbles inside the bottom portion of the drum. Current commercial oil sand conditioning drums operate with a gentle tumbling bed to form oil sand slurry and normally do not turn faster than 25%
of the critical drum speed. In a cateracting slurry drum the solids and slurry continuously dropping in free fall from above onto and into the slurry bed of the drum create a zone of very high turbulence that serves to very quickly convert a mixture of oil sand and water into a slurry suitable for separation by an apertured oleophilic screen. Cateracting normally takes place when the critical speed of the drum exceeds 70% of critical speed. However longitudinal flights mounted along the interior of a slurry drum, that serve as lifters of the undigested oil sand ore can induce cateracting in the drum at significantly lower drum speeds, down to 30% of the critical drum speed "critical speed" of an agglomerator drum is the speed of rotation of an agglomerator drum, containing a bed, in which at least 5% of the bed inside the drum remain in contact with the drum wall at all times due to centripetal force and due to adhesion to the drum wall by bitumen at process temperature. For a conical agglomerator drum, critical speed computation of the drum is based on the largest internal diameter of the conical drum. In an agglomeration drum oleophilic adhesion between cylindrical drum surfaces and ball surfaces due to the presence of adhering bitumen will cause the actual critical speed to be lower than what is normally Jan Kruyer, P.Eng. Thorsby, AB.
calculated as the critical speed of a drum. Below the critical speed the contents tumble inside the drum and do not remain attached to the drum wall at the top of a horizontal drum. The critical speed of an agglomeration drum is different from the critical speed of an ablation drum. In an ablation drum for producing oil sand slurry, bitumen adhesion normally does not have a major effect on the definition of the critical speed of an ablation drum since the bulk of coarse slurry solids do not adhering to bitumen. Thus, the critical speed of an ablation drum normally is higher than the critical speed of an agglomerator drum since agglomerating bitumen is viscous and bitumen coated balls tend to stick to the cylindrical agglomerator wall and take more time to fall away from the wall near the top of the drum than water wetted coarse solids that revolve and tumble in the drum without major bitumen adhesion. The critical speed for an agglomerator drum is defined in these specifications as the surface speed of the inside cylindrical wall of the drum at which balls of specific gravity in excess of 3 and larger than one centimeter in average size remain adhering at all times to the inside cylindrical wall of the drum in the presence of bitumen at the operating temperature of the drum contents. Below the critical speed the bed of balls tumbles inside the rotating drum. For an ablation drum the critical speed is defined as the surface speed of the inside cylindrical wall of the drum at which water wetted gravel larger than one centimeter in average size remains adhering at all times to that inside cylindrical drum wall in the presence of bitumen at the operating temperature of the drum contents. Critical speed may be expressed in RPM, RPS or in surface speed of the inside drum wall for a given drum inside diameter at a selected internal location in the drum away from the end walls.
For a drum that is not conical in shape this internal location may be at any place on the inside cylindrical wall but not in close proximity to the end walls.
"cylindrical" as used herein indicates a generally elongated shape having a circular cross-section of approximately constant diameter.

"de-bituminized" or debituminized refers to a mixture, slurry or suspension from which bitumen has been at least partly removed.
"digested" as used herein refers to the condition of a slurry of oil sand and water that has been ablated sufficiently to be suitable for separation into bitumen Jan Kruyer, P.Eng. Thorsby, AB.
product and de-bituminized tailings effluent after oversize has been removed before such separation.
"endless cable" or "endless rope" is used interchangeably in this disclosure, unless explicitly stated to the contrary, to refer to a cable or rope having no beginning or end, but rather the beginning merges into an end and vice-versa, to create an endless or continuous cable or rope. The endless cable or rope can be, e.g., a wire rope, a non metallic rope, a carbon fiber rope, a single wire, compound filament or a monofilament which is spliced together to form a continuous loop, e.g. by a long splice, by several long splices, or by welding or by adhesion.
"enlarged bitumen" refers to bitumen particles that have been agglomerated in an agomerator to form enlarged bitumen phase particles or bitumen phase fluid streamers for subsequent capture by an apertured oleophilic screen. Enlarged bitumen may contain mineral solids.
"generally" refers to something that occurs most of the time or in most instances, or that occurs for the most part with regards to an overall picture, but disregards specific instances in which something does not occur.
"fluid" refers to flowable matter. As such, fluid specifically includes slurries, suspensions or mixtures (continuous liquid phase with suspended particulates).
In describing certain embodiments, the terms slurry, sludge, mixture, mixture fluid and fluid are used interchangeably, unless explicitly stated to the contrary. A
fluid may be a liquid but it also may be gas. It may be a gas dispersed in liquid or a liquid dispersed in gas.
"multiple wrap endless cables" as used in reference to separations processing refers to a revolvable endless cables that are wrapped around two or more drums and/or rollers a multitude of times to form revolving or revolvable endless apertured oleophilic screen belts having spaced cable wraps. Proper movement of an endless belt with multiple wraps can be facilitated by at least two guide rollers or guides that prevent an endless cable from rolling off an edge of the drum or roller, and guide the cable back to the opposite end of the same or other drum or roller. Apertures of the endless belt are formed by the slits, spaces or gaps between sequential wraps.
The endless cable can be a single wire, a wire rope, a plastic rope, a compound filament or Jan Kruyer, P.Eng. Thorsby, AB.
a monofilament which is spliced together to form a continuous loop, e.g. by splicing, welding, etc. As a general guideline, the diameter of the endless cable can be as large as 3 cm and as small as 0.01 cm or any size in between, although other sizes might be suitable for some applications. Very small diameter endless cables would normally be used for small separation equipment and large diameter cables for large separating equipment. A multiwrap endless cable belt may be formed by wrapping the endless cable multiple times around two or more rollers and/or drums. The wrapping is done in such a manner as to minimize twisting of and stresses in the individual strands of the endless cable. An oleophilic endless cable belt is a cable belt made from a material that is oleophilic under the conditions at which it operates. For example, a steel cable is formed from a multitude of wires, and the cross section of such a cable is not perfectly round but contains surface imperfections because of voids between individual wires on the surface of the cable. The same applies to a rope not made from metal wire. Bitumen captured by such a cable or rope may at least partly fill the voids between the individual wires or strands along the rope or cable surface, and will remain captured in those voids while the bulk of the bitumen is removed from the rope or cable surface in a bitumen removal zone. This residual bitumen trapped between adjacent cable strands on the surface of the rope or cable helps to keep it oleophilic even after the bulk of the bitumen has been removed in a bitumen removal zone. This trapped bitumen serves as a nucleus for attracting more bitumen as the rope or cable subsequently passes through a separation zone.
"oleophilic" as used in these specifications refers to an ability to attract bitumen upon contact. It differs from the conventional accepted term of oleophilic since it is selective and refers specifically to the capture of bitumen on contact by and the adhesion of bitumen to an oleophilic surface, to a bitumen coated surface or to bitumen phase itself. Most dry (not water wetted) metallic, plastic and fibre surfaces are oleophilic or can be made to adhere to bitumen upon contact (or are oleophilic as here defined). A non metallic rope, or a metal wire rope normally is oleophilic and will capture bitumen upon contact unless the rope is coated with an undesirable coating that prevents bitumen adhesion. A plastic rope or metal wire rope that is coated with a thin layer of bitumen normally is oleophilic, since this layer of bitumen Jan Kruyer, P.Eng. Thorsby, AB.
will capture additional bitumen upon contact. A plastic rope or metal wire rope will not adhere to bitumen when it is coated or partly coated with light oil since the low viscosity of light oil will not provide adequate stickiness for the adhesion of bitumen to the rope. In other words, a layer of light oil on the rope surfaces may prevent the attachment of bitumen to the rope wraps. Therefore, such an oil wetted surface is not oleophilic as defined under the specifications of the present invention.
Similarly, a rope (wire or plastic) covered with a thin layer of hot bitumen will not be very oleophilic as defined herein until that thin layer of bitumen has cooled down close enough to the process temperature to allow adequate bitumen adhesion to the wraps of the endless rope at the selected process temperature. Normally the process temperature is less than 50 degrees centigrade and in some cases may be as lower than 5 degrees centigrade, depending on the viscosity of the bitumen phase of the mixture. In some mixtures, minor amounts of lighter hydrocarbons mixed in with the bitumen result in a major reduction in the bitumen phase viscosity at the separation temperature. The optimum processing temperature, therefore, is at least partly governed by the viscosity of the bitumen phase of the mixture being separated.
When the mixture contains a small amount of light hydrocarbon dissolved in the bitumen phase, processing temperature may be as low as one or two degrees above zero degrees centigrade. In the one extreme, when the processing temperature is too high, or bitumen is diluted, the viscosity of the bitumen phase may be too low, causing bitumen phase not adhere well to the screen surfaces. In the other extreme, when the processing temperature is low for aqueous mixtures containing undiluted bitumen, for example, when approaching the freezing temperature of water, bitumen phase may become hard and loose its tackiness and will not adhere to an oleophilic surface.
Therefore, process efficiency is reduced when the mixture temperature is too high or too low. The preferred temperature is somewhere between 20 and 50 degrees centigrade for undiluted bitumen phase.
"oleophilic sieve" is a generic name that applies to any revolving apertured oleophilic screen, including a mesh belt, a conveyor belt, or a perforated belt. Such a sieve captures bitumen on the sieve surfaces in a separation zone and releases bitumen from the sieve surfaces in a bitumen recovery zone. Years ago the inventor Jan Kruyer, P.Eng. Thorsby, AB.
uses mesh belts and standard apertured conveyor belts but these did not perform well under long duration testing. Newer and better belts have been developed that last longer and are more effective. It is not unreasonable to anticipate that,even better and more effective oleophilic sieves will be developed in the future; all of which will capture bitumen phase on the sieved surfaces and allow de-bituminized aqueous phase to pass through the sieve apertures. As used in these specifications, oleophilic sieve or apertured oleophilic screen may refer to a revolving or revolvable apertured oleophilic endless belt made from oleophilic multiple rope wraps or from oleophilic multiple cable wraps. Apertures in such an oleophilic sieve or screen are the slits between adjacent rope wraps or adjacent cable wraps. Rope or cable may be formed into an apertured endless oleophilic belt by means of wrapping an endless cable multiple times around two or more rollers or drums. Alternately, multiple adjacent endless cables may be supported by rollers or drums. Rope generally refers to a non metallic rope and cable generally refers to metallic wire cable. However, rope as used herein may also refer to metal wire rope. When using oleophilic cable wraps to separate bitumen from an aqueous mixture, water and suspended hydrophilic solids pass through slits or voids between sequential wraps, whilst bitumen phase is captured by wraps upon contact in a separation zone. The captured bitumen phase is subsequently removed from the oleophilic wrap surfaces in a bitumen removal zone to become the bitumen product of separation. An oleophilic sieve may also take the form of an apertured endless belt not made from cable wraps, provided it can effectively capture bitumen on its surfaces in separation zones, can effectively release captured bitumen from its surfaces in bitumen removal zones and is long lasting in an industrial environment. In due time several alternate apertured oleophilic endless belts may be developed that will be suitable for use in long lasting commercial equipment to serve as oleophilic sieves. These alternate belts are contemplated for use in the present invention. For that reason the term oleophilic sieve or apertured oleophilic screen is used in these specifications to include any revolvable oleophilic apertured endless belt that has surfaces to which bitumen can adhere for subsequent removal and apertures through which de-bituminized mixture can flow to disposal or reprocessing.

Jan Kruyer, P.Eng. Thorsby, AB.
"oversize" refers to any rigid solids that approach in size the apertures of the apertured oleophilic screen or that approach the linear distance between adjacent cable wrap surfaces, and preferably refers to any solids that approach 10% of the linear distance between adjacent cable wrap surfaces or size of apertures.
Very large oversize particles have difficulty passing mixture dispenser apertures that feed an apertured oleophilic screen and also have difficulty passing between adjacent cable wraps, or through belt apertures. In addition, sand particles from oil sand ore tend to be very abrasive and may cause damage to apertured belts, cable wraps and distributor outlets. Such smaller particles may not block the apertures but may cause major abrasion damage to apertured oleophilic screen and preferably are also removed as part of the oversize before the mixture is allowed to pass to apertured oleophilic screen apertures. The smaller particles of this oversize may be as small as sand. Therefore, any mixture of large mineral rigid particles, which may include abrasive sand size particles may be called oversize as defined in these specifications.
Grizzlies and/or hydrocyclones are devices that may be used to remove oversize from a mixture before it is allowed to pass through an apertured oleophilic screen or oleophilic sieve of the present invention. One such hydrocyclone is disclosed in patent application 2,661,579.
"recovery" and "removal" of bitumen as used herein have a somewhat similar meaning. Bitumen recovery generally refers to the recovery of bitumen from a bitumen containing mixture using an oleophilic sieve or screen. Bitumen removal generally refers to the removal of adhering bitumen from oleophilic sieve or oleophilic screen surfaces. Bitumen is recovered from a mixture in a separation zone through the adherence of bitumen to cable wraps or sieve surfaces upon contact.
Bitumen is stripped from or removed from cable wraps or sieve surfaces in a bitumen removal zone. A bitumen recovery apparatus is an apparatus that recovers bitumen from a mixture. Bitumen must be removed from cable wraps or sieve surfaces continuously in one or more bitumen recovery zones in order for a bitumen recovery apparatus to continue to work properly to capture bitumen from an aqueous mixture on cable wraps or sieve surfaces in one or more separation zones. The same applies Jan Kruyer, P.Eng. Thorsby, AB.
to any apertured oleophilic sieve where bitumen adheres to sieve surfaces and debituminized mixture flows through sieve apertures.
"retained on" refers to association primarily via simple mechanical forces, e.g. a particle lying on a gap between two or more cable wraps. In contrast, the term "retained by" refers to association primarily via active adherence of one item to another, e.g. retaining of bitumen by an oleophilic cable or adherence of bitumen to bitumen coated balls and adherence of bitumen to bitumen coated walls of an agglomerator. In some cases, a material may be both retained on and retained by adjacent cable wraps. However it is highly undesirable for oversize rigid particles to be retained on cable wraps or on oleophilic sieves in the present invention.
"roller" indicates a revolvable cylindrical member or a revolvable drum, and such terms are used interchangeably herein. The drum may have an apertured cylindrical wall and may be an agglomerator drum. On the other hand, a roller may also be a non apertured metal, ceramic or rubber roller.
"sieve" refers to a rugged but flexible long lasting apertured screen, and is used interchangeably with screen unless stated otherwise. In the recent patent applications of the present inventor, sieve generally refers to a screen comprising multiple adjacent wraps of endless cable to form an apertured endless belt. A
"cable screen" is a screen formed by wraps of endless cable.

"single wrap endless cable" refers to an endless cable which is wrapped around two or more cylindrical members in a single pass, i.e. contacting each roller or drum only once. Single wrap endless cables do not require a guide or guide rollers to keep them aligned on the support rollers but may need methods to provide cable tension for each wrap when sequential cable wraps are of different lengths, unless the cable wraps can stretch, and are held in tension. Single wrap endless cables may serve the same purpose as multiple wrap endless cables for separations. When multiple wrap endless cables are specified, single wrap endless cables may be used in stead unless specifically excluded. A cable screen may comprise multiple wraps of an endless cable or may comprise multiple single wrap endless cables. When multiple wraps of endless cables are used, guides or guide rollers are needed for each endless cable to prevent the wraps from rolling off support drums or rollers.

Jan Kruyer, P.Eng. Thorsby, AB.
"slurry" as used herein refers to a mixture of solid particulates and bitumen particulates or droplets in a continuous water phase It normally is used to describe an oil sand ore that has been or is in the process of being digested with water to disengage bitumen from sand grains, resulting in an aqueous suspension of bitumen particles and mineral particles in a continuous water phase that may contain chemicals. The terms "slurry", "mixture" and "suspension" are used interchangeably in these specifications unless specifically identified to the contrary.
"sufficient" as used herein refers to enough, but not too much. For example, when sufficient process aid is added to oil sand during slurry preparation, the amount added is sufficient to achieve the objectives of preparing the slurry. In many cases the oil sand ore itself contains natural detergents that help to prepare the slurry. Also, when recycle water from a tailings pond is used in the slurry preparation step, this recycle water may contain residual process aid and residual detergents that limit the amount of process aid additions required to achieve an acceptable oil sand slurry.
When more than sufficient process aid is added during the slurry preparation step, the excess may interfere with subsequent processing or may result in emulsification of part of the oil sand bitumen. In some cases or for some oil sand ores, process aid is not required at all.

"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.

"surface speed" is the speed of movement of the cylindrical surface of a cylindrical drum, the surface of a conical wall at a specific location on the conical wall or is the speed of movement of the surface of an oleophilic sieve.

Jan Kruyer, P.Eng. Thorsby, AB.
"Tailings effluent" or tailings as used herein is debituminized oil sand slurry that has passed through the apertures of an apertured oleophilic screen. It may refer to tailings soon after these have passed through the apertures but may also refer to tailings that have resided in a tailings pond for a period of time.
"ultrafine mineral particles" as used herein refers to those particles that minimize the release of water from mined oil sand fluid tailings in a tailings pond.
These specifically are thixotropic gel forming colloidal particles, but may also include small oleophilic mineral particles and bi-wetted mineral particles, that are partly oleophilic and partly hydrophilic and normally report to the bitumen phase during oil sand separations by oleophilic sieving.
"velocity" as used herein is consistent with a physics-based definition;
specifically, velocity is speed having a particular direction. As such, the magnitude of velocity is speed. Velocity further includes a direction. When the velocity component is said to alter, that indicates that the bulk directional vector of velocity acting on an object in the fluid stream (liquid particle, solid particle, etc.) is not constant. Spiraling or helical flow-patterns in a conduit are specifically defined to have changing bulk directional velocity.
"wrapped" or "wrap" in relation to a sieve, a wire, rope or cable wrapping around an object indicates an extended amount of contact. Wrap or wrapping does not necessarily indicate full or near-full encompassing of the object.
As used herein, a plurality of components may be presented in a common list for convenience. However, these lists should be construed as though each member of the list is individually identified as a separate and unique member. Thus, no 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-Jan Kruyer, P.Eng. Thorsby, AB.
ranges encompassed within that range as if each numerical value and sub-range is explicitly recited. As an illustration, a numerical range of "about 1 inch to about 5 inches" should be interpreted to include not only the explicitly recited values of about 1 inch to about 5 inches, but also include individual values and sub-ranges within the indicated range. Thus, included in this numerical range are individual values such as 2, 3, and 4 and sub-ranges such as from 1-3, from 2-4, and from 3-5, etc. This same principle applies to ranges reciting only one approximate numerical value.
Furthermore, such an interpretation should apply regardless of the breadth of the range or the characteristics being described.
Bold text in the present disclosure is provided for convenience only.
DETAILED DESCRIPTION OF THE FIGURES

Figure 1 is a general flow diagram representing a current commercial oil sands separation process using bitumen froth flotation. Oil sand is mined (1) and moved by large haulers (2) as ore (3) over a distance to a crusher (4) to break the oil sand into particles sizes that can flow through a slurry pipeline. A cyclo feeder (5) mixes slurry water (7) and air (6) with the crushed ore for introduction into a slurry pipeline (8). Pumps are not shown in this Figures to keep the flow diagram simple.
The pipeline is about 10 kilometers long and the liquid in this pipeline is in turbulent flow to process the oil sand ore with water and air to condition it and produce an aerated oil sand slurry (11). The water (7) is added to the crushed ore in a controlled amount to produce a relatively thick slurry that will allow air to thoroughly mix with and become part of the slurry (11). Additional air (9) may be introduced into the pipeline to assist in the formation of a suitable aerated slurry. Flood water (15) is added near the end of the pipeline to thin the slurry prior to it entering the primary separation vessel (P.S.V.) (12) Aerated bitumen (16) rises to the top of the P.S.V. and is skimmed off to become the froth product of extraction. Middlings (17) from the middle of the P.S.V. join the bottoms (18) of the P.S.V. and flow to a tailings oil recovery vessel (T.O.R.V.) where bitumen froth (13) rises to the top and joins the slurry (11). Middlings from the middle of the T.O.R. flow to a hydrocyclone (20) to Jan Kruyer, P.Eng. Thorsby, AB.
produce additional froth (14) that joins the froth (13) of the T.O.R.V. The underflow of the hydrocyclone (20) joins the tailings (22) of the T.O.R.V. to become the final tailings (23) of the extraction process, which flow to a tailings pond (not shown).
Except when gravity flow is feasible, each process stream is moved by a pump under suitable control. This makes this a complex process that requires constant monitoring.

While this information is not readily available, the total residence time required to resolve oil sand ore to bitumen product and tailings may be estimated to required well over an hour. Residence time in the P.S.V. reportedly is about minutes and residence in the T.O.R.V. may be estimated to be about 45 minutes for a total residence time in these two vessels of about 90 minutes to achieve acceptable bitumen product recovery. Bitumen recovery would be seriously reduced, and the commercial process would be less than satisfactory if shorter residence times were used.

Figure 2 is a flow diagram of a proposed oil sands separation process that uses an oleophilic Sieve in the form of an agglomerator and apertured oleophilic screen to separate oil sand ore adjacent to a mine face. It eliminates the long pipeline of Figure 1 and may be located near the mine face. Oil sand ore (40) is mined (42) at the mine face (41) and is fed into a multi stage crusher (43) that breaks the oil sand ore into large gravel size chunks and is introduced into a serpentine pipe (44) with water (56 and 57) to produce a slurry. This water comprises recycle water (56) from a dewatering conveyor and fresh make up water (57). Make up water is required since the solid tailings (55) normally contain approxiately about 20% water that leaves the system with these tailings (55) but may be recovered in part lateron. A
serpentine pipe (44) for producing oil sand slurry induces high turbulence and impact forces in its interior to digest oil sand ore with water. The serpentine pipe is described by the present inventor in pending Canadian patent application 2,638,551.
The slurry (45) enters a confined path hydrocyclone (46) which features a coiled pipe upstream of the hydrocyclone body. The confined path hydrocyclone is described by the present inventor in pending Canadian patent application 2,661,579. The coiled pipe of this hydrocyclone is provided with fluid inlets along its outside lane. Fluid is Jan Kruyer, P.Eng. Thorsby, AB.
injected through these inlets and serves to drive dispersed bitumen particles from the outside lane to the inside lane of the coiled pipe and causes these to report to the hydrocyclone overflow (48). The coiled pipe may be of constant curvature or of progressively increasing curvature in the direction of flow. The fluid (47) used in this Figure may be air, wash water, gas, or gas dissolved in water. Additional make up water (49) may be provided but normally is not required nor desired since the slurry (45) of Figure 2 is more fluid than the thick slurry produced in the slurry pipelines or in the conditioning drums of conventional oil sands plants. In a commercial bitumen froth flotation plant the slurry must be thick enough to capture air bubbles.
Flood water is then added in the conventional flotation plant to thin the slurry so that aerated bitumen can rise to the top of separation vessels past settling gravel, sand and silt.
The slurry used for sieving by an oleophilic sieve normally is thinner than the slurry produced in the slurry pipeline but normally is thicker than the flooded slurry used in the P.S.V. of a conventional plant.

Gravel and coarse sand leave the hydrocyclone (46) as underflow (55) and are deposited at a desired location (54) on the dewatering conveyor (53) and dewater on the dewatering conveyor (53). The underflow is relatively coarse and dewaters rapidly to produce recycle (56) water that flows down the incline of the conveyor while the coarse solids move up the incline of the slowly moving conveyor (53). The overflow (48) from the hydrocyclone (46) enters an agglomerator (59) that has an oleophilic sieve (62) wrapped around the apertured cylindrical wall of the agglomerator. The sieve may comprise multiple cable wraps to form a, sieve that has longetudinal members but no cross members. This oleophilic sieve apparatus and method is described by the present inventor in a number of pending Canadian patents including 2,638,596 and 2,638,474 and 2,653,058 and 2,666,025 and 2,690,951.
In Figure 2, the oleophilic sieve is illustrated in the form of a revolving drum (59) with apertured cylindrical wall (50) where cable wraps are in close proximity to the drum apertures to allow capture of bitumen by the cable wraps as de-bituminized aqueous phase of the slurry passes between the cable wraps to disposal as fine effluent (52).
Bitumen product (51) is removed from the moving cable wraps in a bitumen removal zone (58). The drum is not immersed but a baffle (51) is provided to manage the fine Jan Kruyer, P.Eng. Thorsby, AB.
effluent (52) that leaves the oleophilic sieve (59) and direct it to a desired location (55) on the dewatering conveyor (53). Water from the fine effluent (52) flows down the incline of the conveyor and is filtered by the coarse underflow (55) deposited on the moving conveyor at the chosen location (54) before this water becomes part of the recycle water (56). The effluent fines (52) contain fine sand, silt, and clay.
The coarser fractions of the fine effluent (52) reports to the moving conveyor (53) but water and the finer fraction of the effluent (52) is filtered by the coarse and fine deposit on the top flight of the conveyor before it reports to the recycle water (56).
Since the top flight of the conveyor (53) moves upward, dewatered solid tailings (55) containing about 20% water, fall off the conveyor and are discarded. Upon standing these discarded tailings may release some additional water which can be used as part of the process water (57) but this water will have cooled, while recycle water (56) from the conveyor (53) will contain heat content not yet lost to the environment. Hot water may be used for the supply of make up water (57) to maintain a desired slurry (45) temperature which normally is between 20 and 50 degrees centigrade for oleophilic sieving of oil sand ore slurries.
In the above referenced pending patents of the present inventor, and in his expired patents, a wide range of oleophilic sieve configurations and methods are described. Any one of these configurations may be used for and fitted in as the oleophilic sieve of Figure 2 if suitable and desired. In all cases the sieve involves a revolving apertured oleophilic screen and may use cable wraps of metal or plastic rope. The mesh belts and industrial apertured conveyor belts disclosed for that use in the expired patents by the present inventor did not last long enough or are not as effective for separations as the more recent cable belts of his pending patents.
One feature of the dewatering conveyor is that it preserves some of the process heat content into the recycle water, since the dewatering process here described results in a relatively warm recycle water and reduces the demand for additional heat to form the slurry.
Hydrocyclones may be used instead of dewatering conveyors (53) to dewater the fine effluent (52). The coarse underflow from such hydrocyclones may be deposited temporarily on an inclined slab to allow water to run off before the coarse Jan Kruyer, P.Eng. Thorsby, AB.
tailings are used for oil sand site reclamation purposes. Furthermore, coarse tailings (55) may be mixed with underflow from hydrocyclones when hydrocyclones are used to dewater fine effluent (52) for reclamation purposes.

Figure 3 is a flow diagram very similar to the flow diagram of Figure 2 but it includes a number of optional features that take advantage of modifications possible when an oleophilic sieve is used to separate mined oil sand ore. In this case the serpentine pipe is replaced by a cateracting high speed ablation drum (73) to digest crushed oil sand ore with water. In the prior art of oil sand separation using bitumen froth flotation, conditioning drums are or have been used instead of slurry pipelines to ablate the oil sand ore with water and condition it to become a slurry. These conditioning drums require careful control of slurry water content and drum rotation, speed to encourage the capture of air into the slurry before it is flooded with water and introduced into the P.S.V. However, the oleophilic sieve does not require the capture of air into the slurry. It does not require careful control of the water content of the slurry to keep it thick before it is flooded, since it does not flow into a P.S.V.
As shown in Figure 3, all the required water for producing and separating an oil sand slurry is add to the oil sand ore at the beginning, after it is crushed. The crushed ore and water enter a high speed ablation drum rotating rapidly. In some cases the rotation rate may be as high as 80% of the critical RPM but it may be as low as 30%
of the critical RPM when lifters are used in the drum as described with Figure 4. The interior is provided with strong longitudinal flights (not shown in Figure 3) that lift the drum contents and are designed to stand up to internally falling or cateracting rocks and gravel that form part of the crushed ore. These rocks and gravel, coming from the mine face, assist in digesting the slurry by pounding the oil sand ore and pulverizing the oil sand in the presence of an abundance of water to form a slurry that is screened by a grizzly (78) to remove rocks, and gravel from the slurry leaving the drum (73). This grizzly (78) may be a single grizzly or may consist of a number of grizzlies in series to remove rocks and gravel from the slurry of progressively smaller solids dimensions. The oversize may be washed with water and this wash water may be added to the slurry feed (76) for the hydrocyclone (77). Overflow (81) from the Jan Kruyer, P.Eng. Thorsby, AB.
hydrocyclone (77) flows to the agglomerator and oleophilic screen as in Figure 2 but the underflow is temporarily deposited onto a slab that forms a membrane (90) and allows the collection of water run off (75) that may be used as recycle water to produce more slurry. Fine aqueous effluent (87) flows over the top of the solid tailings (89) and allow it to filter through the solid tailings to capture fines in the voids between the sand grains of the solid tailings. The water run off (75) will contain fine silt and clay but, as shown in Example 1, these fine solids do not interfere in slurry separation by an oleophilic sieve, especially when steady state fines content is achieved in the water run off (75) due to the capture of fines in the voids between sand grains of the solid tailings (91). Like the top flight of the conveyor of Figure 2, the membrane (90) of Figure 3 collects and dewaters both coarse and fine tailings.
Normally a larger amount of tailings collect on the membrane (90) than on the conveyor and more heat is lost from these tailings than from the conveyor of the previous Figure. The membrane may be horizontal or may be sloped, and earth moving equipment may be used for the removal of the dewatered tailings. As in Figure 2, an oleophilic sieve separates the hydrocyclone overflow into bitumen product (84) and effluent (87). A hydrocyclone may also be used to dewater the effluent (87) to yield water run off (75) from its overflow while its underflow may join the underflow (86) of the confined path hydrocyclone to produce additional recycle water run off (75) Figure 4a is an isometric drawing of a cateracting drum for producing an oil sand slurry for the present invention. The cylindrical drum wall (104) is supported on slewing rings (103 and 105) in contact with driven rollers (not shown).
Crushed oil sand ore and water enter the drum through an entrance (100) which is connected to the drum through a seal (101) in a drum end wall (102). The oil sand ore, water and the resulting digested slurry normally fills 30 percent or more of the drum volume.
Slurry leaves through an exit (107) in the opposite end wall (106). Lifters (108) are mounted longitudinally on the drum interior cylindrical wall (111) and baffles (109) mounted on or adjacent to the lifters (108) slow down the flow of undigested oil sand ore through the drum but readily allow the flow of digested slurry through the drum Jan Kruyer, P.Eng. Thorsby, AB.
from entrance to exit. A plow (not shown) lifts the slurry near the exit end wall (106) of the drum and transfers it to the exit (107). Hardened teeth (110) may be mounted in the drum inside to break oil sand lumps cateracting in the drum. No slurry is shown in this Figure to keep the drawing simple. Current conventional oil sand conditioning drums have a length to diameter ratio between 5 and 6. A
cateracting slurry drum of the present invention has a length (L) to diameter (D) ratio between 1 and 3.

Figure 4b is an inside view of the drum of Figure 4a through section A-A of Figure 4a. The cylindrical drum wall (104) is supported by sets of slewing rings (105) that mate with sets of rollers (116). The slewing rings (105) may be supported circumferentially by at least two sets of rollers (116) mounted far enough apart to keep the drum from jumping off its roller supports. However, since a cateracting drum turns rapidly and is exposed to major unbalanced stresses, three or four sets of mounted rollers in contact with the slewing rings normally will provide for more effective containment of the drum on its supports. The direction of drum rotation is shown with the arrow (115) and lifters (108) are shown in end view. Rollers (116) may be flanged to keep the slewing rings and drum in proper alignment while shafts (117) position the rollers. Dashed lines (114) show the radial contact surface of the rollers ( 116). Baffles (109) slow down the flow of undigested oil sand lumps through the drum from entrance to exit. Slurry can pass under the baffles but undigested oil sand lumps do not readily pass by these baffles (109) except in the cut out portion (113) of the baffles. These cut out sections of the baffles allow the flow of undigested oil sand, rocks and undigested clay through the drum but at a reduced rate. Dotted lines (120 and 121) show the cateracting flow of oil sand slurry and undigested oil sand lumps and rocks inside the rotating drum. The open arrows (122) illustrate the direction of flow. Hardened teeth (123) may be mounted inside the drum to catch and break up oil sand lumps that fall or flow down into the slurry due to the cateracting activity in the drum. The lower dotted lines (120) give an indication of the cateracting flow of the oil sand and water mixture in the drum when lifters (108) are not present and the drum rotates at cateracting speed, or when the Jan Kruyer, P.Eng. Thorsby, AB.
drum rotates at a lower speed and the lifters (108) help to induce cateracting of the drum contents. The upper dotted lines (121) give an indication of the cateracting flow of the oil sand and water mixture in the drum when the drum rotates at a faster speed and the lifters (108) cause the contents of the drum to be lifted higher up in the drum before falling back down into and onto the drum contents near the middle or bottom of the drum. The cateracting drum of Figures 4a and b is designed to rotate at a drum speed that is between 30% and 80% of its critical speed. Its residence to produce an acceptable slurry for separation by an agglomerator and oleophilic sieve is less than 3 minutes and in some cases may be considerably less than 2 minutes.
In most cases a process aid, such as sodium hydroxide is not required to produce a properly digested slurry in the processes of Figures 2 and 3.
However in some cases the use of a process aid is desired. It is the objective of the present invention to allow the use of a suitable process aid, such as sodium hydroxide, sodium carbonate sodium silicate, calcium hydroxide or calcium sulphate when that process aid will help in the production of a suitably digested oil sand slurry.
SPEED OF SEPARATION

As mentioned above with reference to Figure 1, the residence time in the conventional P.S.V. is approximately 45 minutes in the T.O.R.V. vessel another approximately 45 minutes for a total of 90 minutes in these two vessels, ignoring for simplicity sake the hold up in the various recycle loops illustrated in Figure 1. The only bitumen recovery device used for the present invention is the agglomerator with its surrounding apertured oleophilic screen illustrated in Figures 2 and 3.
Tests were conducted in a pilot plant with a screen similar to Figure 2. It used a drum 1.108 meters in diameter and 0.095 meters in length to keep the pilot plant small enough to conserve feedstock and yet yield acceptable pilot plant results. The feed rate of bitumen containing mixture was 2 cubic meters per hour and the bitumen content of the aqueous mixture was 6.07 wt%. The drum was filled to 50% of its volume with bitumen coated balls, with voids between the balls. Bitumen filled a large portion of the voids between the ball surfaces. About 10% of the drum volume was air as Jan Kruyer, P.Eng. Thorsby, AB.
determined by the level of de-bituminized mixture in the apertured drum, observed flowing out of the upper drum apertures not covered by the oleophilic screen.
The upper portion of the drum was not covered by the screen and mixture could flow out of the drum when this level became too high, and then conveniently flowed down the drum wall and passed through the screen apertures. However, the feed rate into the drum was controlled to minimize flow through the uncovered drum apertures. As a result, the separating feed mixture in the drum occupied approximately 40 percent of the drum volume during separation. Based on these data, the mixture volume in the drum during separation was 0.4(it)(1.108)(1.108)(0.095)=0.147 cubic meters and the flow rate was (2)/60= 0.0333 cubic meters per minute, resulting in a residence time of (0.147)/(0.0333)= 4.4 minutes. Dividing this into 90 minutes results in a separation rate by the apertured oleophilic screen that is about 20 times as fast as froth flotation.
However this is a comparison between pilot plant data and commercial data and may not take into account all the variables between the two separation methods.
However it is reasonable to assume from the above findings the very encouraging and unexpected result that oil sand separation using an apertured oleophilic screen is an order of magnitude faster than oil sand separation that uses conventional froth flotation methods. Not only is the process faster but it requires fewer flow loops and is more energy efficient. Another major difference is that a high speed ablation drum (73 of Figure 3) may be used to prepare the slurry; a drum that is much smaller and faster than the gentle conditioning drums of commercial plants that required slow rotation rates to capture air in the thick slurry before water flooding. The high speed ablation drum can handle a higher water content in the rapidly rotating slurry, resulting in faster slurry preparation but without air entrainment in the slurry. Since the oleophilic sieve does not require air in the slurry, this is not a problem. A fluid, such as water, air, gas or gas dissolved in water is used in small amounts in the process of Figures 2 and 3 to drive residual bitumen to the inside lane of the confined path upstream from the hydrocyclone (46) or (77) body of the respective Figures. It scavenges for finely dispersed bitumen and serves to collect an increased amount of bitumen in the hydrocyclone overflow being fed to the oleophilic sieve and, reduces or eliminates bitumen in the underflow of the hydrocyclone.

Jan Kruyer, P.Eng. Thorsby, AB.
While sieving of a slurry in a pilot plant may take only 4 minutes, Residence time in a commercial plant may take longer, such as 7 minutes, due to the choice of equipment, the need for safety and the need for additional pumps and piping, etc., but is not expected to exceed 20 minutes.

PRIOR ART

In Canadian patent 2,029,795 Cymerman discloses the use of pipelines to convert mined oil sand and water into oil sand slurry. For comparison purposes he provides information on existing conventional conditioning drums in use by industry to prepare oil sand slurry for separation. These drums are still in use to produce oil sand slurry for separation but newer separation plants use the slurry pipelines proposed by Cymerman. According to the supplied information, a typical commercial conditioning drum is 30.5 meters long and 5.5 meters in diameter, for a drum volume of (,n)(5.5)(5.5)(30.5)/4 = 725 cubic meters. The oil sand feed rate to the drum is 4500 metric tons per hour, which at a specific gravity of 2.1 is 2143 cubic meters per hour.
Water at 95 centigrade and liquid process aid added to the drum add another tonnes per hour to the drum, which at a specific gravity of 1.0 is 1105 cubic meters, for a total feed rate of 3248 cubic meters per hour entering the 725 cubic meter drum.
The stated residence time in the drum to produce an acceptable slurry is 3 minutes, or 1/20 hour. Based on that information, the percentage fill of the conditioning drum is (100)(3248)/(725)/(20)=22.4%. The water content of the tumbler produced slurry may be computed when it is assumed that oil sand ore contains about 4.0 wt%
water, 11 % bitumen and 85% solids. The resulting slurry produced per hour then contains 3825 metric tons of solids (67.7%), and 495 metric tons of bitumen (8.8%) and metric tons of water (23.5%). This slurry is kept thick on purpose to capture air bubbles, which would not be captured if the slurry were much thinner. Then metric tons of flood water are added to this slurry per hour to yield a thin slurry that contains 50% solids, 6.5% bitumen and 43.5% water before it enters the separation vessels. (P.S.V, T.O.R.V. , etc.) This information provides a basis for comparison for Jan Kruyer, P.Eng. Thorsby, AB.
the present invention and was computed from the Cymerman patent which was based on factual commercial oil sand separation plant data.
In Canadian patent 1,141,318 the present inventor disclosed a conditioning drum that contains oleophilic surfaces which serves to convert a feed of water and mined oil sand into a slurry but which also, in the same drum, agglomerates the bitumen particles by means of oleophilic drum surfaces to cause small bitumen particles to become larger for subsequent capture by an oleophilic sieve. This drum serves the dual purpose of slurry production and bitumen agglomeration and therefore the residence time in this drum was considerably longer than if slurry production were the only purpose. This is illustrated in Example 1 of that patent based on pounds and feet. The pilot plant drum size is 3 feet long and 2 feet in diameter for an internal volume of (n)(2)(2)(3)/4 = 9.4 cubic feet. One thousand pound of wet oil sand per hour containing 80.5% solids, 7.5% bitumen and 12.0% water were fed into the drum along with 100 pounds of water at 60 F and 50 pounds of steam at 5 psi.
Assuming that the wet oil sand had a specific gravity of 2.0 and water and condensed steam had a specific gravity of 1.0 allows us to reconstitute the data from this patent.
The volume of oil sand feed is (1000)/(62.4)/2 = 8.1 cubic feet per hour and the volume of water and steam added is (150)/62.4 = 2.4 cubic feet for a total of 10.5 cubic feed entering the drum per hour. The drum rotates at 10 RPM. Critical speed for this drum is (2936/1)05 = 54 RMP, indicating that it turns at 18.5% of critical speed.
Residence time of slurry in this drum is not detailed in this patent but it may be computed from the slurry volume in the drum, which was between 35 and 40% and which also is verified in Figures 3 and 4 of that patent. Slurry filling 37%
of the drum volume represents a slurry volume at all times in the drum of (0.37)(9.4) = 3.5 cubic feet, and comparing this with 8.1 cubic feet per hour of slurry flow results in a residence time of 0.43 hours or 26 minutes of residence time to achieve both slurry preparation and bitumen agglomeration. Since patent 1,141,318 was granted, major strides were made in speeding up slurry preparation and bitumen agglomeration.
To achieve an improvement, slurry preparation and bitumen aglomeration were thereafter disengaged from each other. Separate drums of different drum designs were Jan Kruyer, P.Eng. Thorsby, AB.
developed for slurry preparation that were different from drums developed for bitumen agglomeration. This improved and reduced processing time in both.
In Canadian patent 1,134309 Tchernyak discloses the use of steam sparging tubes and sparging valves in oil sand conditioning drums to properly introduce steam into the slurry being produced. He refers to Canadian patent 918,588 where Marshall et. al. disclose conditioning drums that use steam to produce a slurry from oil sand ore and water. That patent does not provide an indication of the RPM of the drum. It describes the need for steam and uses a steam distributor valve and perforated steam ducts to inject steam into the slurry. It also mentions, but does not claim feed flights with sharp edges near the entrance of the drum to force the oil sand into the drum interior.

A major difference from the prior art is that steam is not used in the slurry preparation drum disclosed in the present invention. The slurry preparation drum is smaller, turns faster and requires less time to produce the slurry; and the slurry is thinner than conventional commercial oil sand slurries before flooding.
AT THE MINE FACE

Current commercial oil sand mining equipment moves as the mine face recedes and conventional commercial earth movers transport the surface mined oil sand to a crusher, as shown in Figure 1. From there, a long slurry pipeline transports the mined ore and water over a long distance to the extraction plant where it arrives as a conditioned and aerated slurry suitable for flooding with water and separation by bitumen froth flotation in P.S.V and T.O.R.V. vessels which require long residence times and large equipment. The current commercial oil sand separation plants are too large and heavy to allow these to be moved with the receding mine face, but the mining equipment has to move with the mine face. Because of that reality, conversion of oil sand to bitumen is an expensive process.

However the present invention provides for separation equipment that is an order of magnitude smaller than the size of current commercial froth flotation extraction plants and thus may allow the use of extraction plants that move with the Jan Kruyer, P.Eng. Thorsby, AB.
mine face. Unlike the required huge tailings ponds of the current commercial plants, the process of the present invention eliminates the need for tailings ponds and allows reclamation of the oil sand site on a continuous basis as portions of the oil sand lease are mined out.

As shown in the following example, oil sand separation by the process of bitumen sieving from slurry is highly tolerant of fines in the process water.
Filtering of the process recycle water through tailings sand results in a stream of process water in which the fines content remains constant. The fines are continuously captured in the voids of the tailings sand. By this method, oil sand tailings ponds may be eliminated and site remediation may start as soon as only a portion of an oil sands lease has been mined out. All this is possible because sieving bitumen from oil sand slurry is very tolerant of process water fines content.

EXAMPLE

The results of processing of oil sand ore are shown in the following example in kilograms. The present inventor obtained these data during a small-scale research pilot plant program to evaluate the merits oleophilic sieving of low-grade oil sands.
Kilograms Total Bitumen Minerals Water Feedstock 1929 175 1654 100 Product 363 167 79 117 Fresh water 508 Recirculation water 391 1 85 305 Oversize reject 28 1 24 3 Tailings 2007 2 1553 452 The ore was dry screened and oversize was removed from the feed before separation of the undersize. Load cells were used to accurately measure each stream.
Total in was 2828kg. Total out was 2796kg. Considering experimental error, Jan Kruyer, P.Eng. Thorsby, AB.
sampling of the streams for analyses, and water evaporation accounted for about 30 to 40 kg during the 7 hour run.
Based on these pilot plant data of processing screened ore that contained 9.1%
bitumen, the bitumen recovery was 95.4% and the bitumen product contained 46.2%
bitumen, 21.7% solids and 32.1 % water. The recirculation water contained 22%
mineral fine solids, which did not interfere with the 95% efficient oleophilic sieving process but resulted in an increase in the fines content of the product. No attempts were made at that time to wash the bitumen product and reduce its minerals content.
The tailings were "dry tailings" containing 22.5% water and the recycle water was tailings run off water that was returned immediately and continuously to the separation process.

Total water content of the slurry was (100+508+305) = 913 kg and total solids and bitumen content was (1654+175) = 1829 kg, for a total of 2742 kg, resulting a slurry water content of (100)(913)/2742 = 33.3 % which is about mid way between the conventional thick aerated slurry coming from a conditioning drum and the conventional flooded slurry that is sent for bitumen froth flotation to the P.S.V. and T.O.R.V.

The pilot run lasted 7 hours. Runs longer that 7 hours in duration might have resulted in minor changes in the solids contents of the recycle water.
However, this depends on the efficiency of recycle water filtering through tailings sand and the transfer of fines interstitially to the voids of the tailings sand.
Expectedly, this transfer of solids from the recycle water to the tailings sand voids will vary with various grades of oil sand feedstock. Using recycle water in this manner saves on energy requirements since the water is recycled before it cools significantly.
A
conveyor belt similar to the conveyor of Figure 2 was used for dewatering the tailings and for filtering the recycle during this test run. However the tailings dewatering method of Figure 3 may be used instead.

An important promise of the present invention is that the methods and equipment described herein involve fewer fluid recycle loops and require a lower degree of equipment and operator control of the separation process than is used or required in the current commercial oil sands plants. The lack of recycle loops is Jan Kruyer, P.Eng. Thorsby, AB.
obvious from a comparison between Figure 1 versus Figures 2 and 3. In an industrial process, each recycle loop tends to adds to the complexity and cost of a separation plant, since each may need one or more pumps, level and flow controls and stream sampling and composition controls; and with an attendant demand for expert operator involvement.
Of course, it is to be understood that the above-described methods, arrangements 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 reagent addition, concentration, temperature, 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.

Claims (20)

1. A method for producing from oil sand ore and water a slurry containing less than 65 weight percent solids which method uses an at least 3 meter diameter generally horizontal cylindrical ablation drum, wherein a) the drum has an entrance at one end and an exit at the opposing end and rotates at between 30% and 80% of critical drum speed, wherein b) the drum receives mined oil sand and water through its entrance and mixes the oil sand and water in cateracting mode inside the drum to produce in less than 3 minutes a digested oil sand slurry, wherein c) the slurry leaves the drum through its exit, wherein c) oversize is removed from the slurry after the slurry has left the drum exit, and wherein d) after the oversize is removed the slurry is suitable for separation by a revolving apertured oleophilic screen into bitumen product and de-bituminized tailings effluent.

2. A method as in Claim 1 in which the ablation drum is larger than 5 meters in diameter and rotes between 30% and 60% of critical speed wherein lifters mounted along interior wall of the cylindrical drum cause cateracting of the oil sand and water to produce the slurry and wherein the drum is inclined downward less than 5 degrees from entrance to exit and a hydrocyclone is used to remove oversize before separation of the slurry into bitumen product and de-bituminized tailings effluent.

3. A method as in Claim 1 wherein a grizzly is used to remove rocks and gravel from the slurry after the slurry has left the drum exit and before a hydrocyclone is used to remove oversize from the slurry.

4. A method as in Claim 1 wherein hardened teeth mounted inside the drum break up cateracting lumps of undigested oil sand.

5. A method as in Claim 1 wherein the revolving apertured oleophilic screen is partly wrapped around apertured cylindrical wall of a bitumen agglomerator.

6. A method as in Claim 1 for using a revolving apertured oleophilic screen comprising multiple adjacent cable wraps to separate in less than 20 minutes the oil sand slurry into bitumen product and de-bituminized tailings effluent after the oversize is removed.

7. A method for using an apertured oleophilic screen comprising multiple adjacent cable wraps partly supported by cylindrical apertured wall of an agglomerator to separate oil sand slurry into bitumen product and de-bituminized tailings effluent by sieving in less than 20 minutes after the oversize is removed.

8. A method as in Claim 7 by sieving in less than 10 minutes.

9. A method as in Claim 7 by sieving in less than 5 minutes.

10. A method for producing an oil sand ore slurry containing less than 65%
solids by weight which method involves mining an oil sand ore, crushing the mined oil sand ore, digesting the crushed oil sand ore with water to form the slurry and separating the digested slurry into oversize and undersize by means of a hydrocyclone wherein oversize reports to the hydrocyclone underflow and undersize reports to the hydrocyclone overflow and separating in less than 20 minutes the hydrocyclone overflow by means of an oleophilic sieve into bitumen product and de-bituminized fluid tailings effluent.

11. A method as in Claim 10 and separating the hydrocyclone overflow in less than 10 minutes.

12. A method as in Claim 10 and separating the hydrocyclone overflow in less than 5 minutes

13. A method as in Claim 10 wherein de-bituminized fluid tailings effluent is filtered through a bed of mineral particles to yield recycle water that may be used as part of a water supply for preparing oil sand slurry.

14. A method as in Claim 13 wherein the bed of mineral particles comprise hydrocyclone underflow.

15. A method as in Claim 10 wherein mined oil sand is digested in water to form a slurry and after oversize has been removed this slurry is separated by an oleophilic sieve within three kilometers from the mine face where the oil sand is mined.

14. A method as in Claim 10 wherein mined oil sand is digested in water to form a slurry and after oversize has been removed this slurry is separated by an oleophilic sieve within 500 meters from the mine face where the oil sand is mined.

15. An apparatus for producing in less than 3 minutes a digested oil sand slurry from crushed oil sand ore and water comprising a rotatable drum with cylindrical wall larger than 4 meters in diameter and provided with an axial drum inlet and an axial drum outlet and wherein said drum and its supports are constructed strong enough to allow a charge of oil sand and water introduced into the drum and filling at least 30 percent of the drum volume to tumble in cateracting mode at a selected drum speed between 30% and 80% of critical drum speed and the drum is provided with a suitable drive for rotating at the selected drum speed.

16. An apparatus as in Claim 15 provided with generally horizontal lifters along or adjacent to cylindrical wall of the drum, wherein the drum and its support are constructed strong enough to allow the charge to rotate in cateracting mode at a selected drum speed between 30% and 50% of its critical drum speed and is provided with a suitable drive for rotating at the selected speed.

17 An apparatus as in Claim 15 wherein the drum has a length to diameter ratio that is less then 2.

18. An apparatus as in Claim 15 that allows production of digested oil sand slurry in less than two minutes.

19. An apparatus as in Claim 15 wherein provision can be made to add a process aid to the crushed oil sand ore or to the water.

20. An apparatus as in Claim 15 wherein oil sand slurry leaving the drum is screened by vibrating grizzlies to remove oversize exceeding 2 centimeters in average dimension and wherein wash water after removing superficial bitumen from the oversize is returned to the slurry.