Patent Application
20250059446
The present invention relates to methods and process aid compositions for improving froth quality and bitumen recovery during bitumen extraction. In particular, the disclosure provides a method for using multivalent ionic liquids and binary process aid combinations for improving bitumen extraction efficiency and reducing water and mineral solids in bitumen froth.
Oil sands, also known as tar sands, are mixtures of clay, sand, water, and heavy hydrocarbons, such as bitumen. Bitumen is a complex and viscous mixture of large or heavy hydrocarbon molecules, which provide a source of hydrocarbons for petrochemical industry. However, many of the known processes for separating and recovering hydrocarbons from oil sands ore are expensive and complex.
Oil sand deposits, such as the Athabasca oil sand deposits, are extracted by surface mining. The mined oil sand is trucked to crushing stations for size reduction, and fed into slurry preparation units for bitumen extraction. Bitumen extraction can be achieved by an In-Pit Extraction Process (IPEP), wherein raw oil sands ore is transferred to a flotation cell. A froth-flotation process is then used to separate bitumen from mineral ore solids and water. During this process, oil sands ore is mixed with heated water or steam, optionally also with a process aid to form a slurry, which is transferred to a separation tank. Separation under quiescent conditions results in formation of layers, including (i) a top layer of bitumen froth, which comprises bitumen, water and small amount of mineral solids, (ii) a middle layer of middlings (i.e., warm water, fines, residual bitumen), and (iii) a bottom layer of tailings mainly water, mineral solids, and coarse (i.e., warm water, coarse solids, residual bitumen). The bitumen froth, middlings, and tailings are separately withdrawn and the bitumen froth fraction is processed further for recovery of the bitumen. During further processing, the bitumen froth is de-aerated, heated, and diluted with a suitable hydrocarbon solvent to produce diluted bitumen, which is further processed to produce synthetic crude oil and other valuable commodities.
Generally, the separated bitumen froth should contain as small amounts of water and mineral solids as possible. If water and/or minerals solids content is too high, the bitumen is not directly suitable for pipelining or further refining. Similar problems may also occur during recovery of oil from oil shale.
The IPEP extraction process should result in high bitumen froth quality (i.e., ratio by mass of recovered bitumen to mineral ore solids in the bitumen froth) and high bitumen recovery (i.e., ratio by mass of recovered bitumen to oil sands ore). Average bitumen froth composition consists of 60% bitumen, 30% water, and 10% mineral solids; therefore, the current industrial baseline performance level is a froth quality of 6.
Increasing the froth quality during IPEP is very challenging. One undesirable option is to slow down froth treatment by increasing residence time in the flotation cell and the following separation tank in order to achieve acceptably low levels of water and mineral solids. One or more additional process steps may also be required, which complicates production and increases costs. Alternatively, and more desirably, process aids may be added to the raw mineral ore during froth-flotation to improve froth quality and bitumen recovery.
Some industrial processes improve froth quality by adding caustic (e.g., sodium hydroxide) as a process aid. Caustic helps the release of natural surfactants and affects surface properties of bitumen, sand, and clays, and reduces the attachment of fine solid particles on bitumen surface. However, the use of caustic creates undesired consequences. Caustic is toxic and corrosive, impacting health and the environment and causing scaling on equipment due to precipitation of divalent cations when it is added to the slurry water for slurry preparation.
Considerable effort has been directed toward developing new process aids to reduce or obviate the use of caustic. CA 2937014 discloses use of anionic surfactants and caustic as process aids. U.S. Pat. No. 9,469,814 and CA 02880959 disclose use of sodium citrate and caustic as process aids. However, despite these efforts, caustic remains a key component of the process aids.
The present invention addresses this issue by exploring a wide range of chemical additives, including multivalent ionic liquids and binary process aid combinations, for use as process aids during bitumen extraction. Among all chemistries investigated, tricholine citrate showed the most desirable improvements in froth quality and bitumen recovery.
It is an object of the invention to provide methods and process aids for improving froth quality and bitumen recovery during bitumen extraction, which totally obviate the use of caustic.
The present invention relates to methods and process aid compositions for improving froth quality and bitumen recovery during bitumen extraction. In particular, the disclosure provides a method for using multivalent ionic liquids and binary process aid combinations for improving bitumen extraction efficiency and reducing water and mineral solids in bitumen froth. The inventive method utilizes multivalent ionic liquids, particularly tricholine citrate, and binary process aid combinations to improve both froth quality (i.e., ratio by mass of recovered bitumen to mineral ore solids in the bitumen froth) and bitumen recovery (i.e., ratio by mass of recovered bitumen to oil sands ore) during bitumen extraction.
In one aspect, the present invention provides a method for extracting bitumen from oil sands ore to produce a bitumen froth, the method comprising:
In some exemplary embodiments of the method:
In some exemplary embodiments said process aid comprises
In some exemplary embodiments of the method:
In some exemplary embodiments of the method:
In some exemplary embodiments of the method:
In some exemplary embodiments of the method said single process aid comprises tricholine citrate at a dosage ranging from 50-500 ppm, 100-500 ppm, or 200-300 ppm.
In some exemplary embodiments the method results in:
In another aspect, the present invention provides a method for extracting bitumen from oil sands ore to produce a bitumen froth, the method comprising:
In some exemplary embodiments of the method:
In some exemplary embodiments of the method said process aid comprises:
In some exemplary embodiments of the method said process aid comprises:
In some exemplary embodiments of the method:
In some exemplary embodiments the method results in:
In another aspect, the present invention provides a composition comprising:
The invention will be described in more detail with reference to appended drawings, described in detail below.
Before describing the invention, the following definitions are provided. Unless stated otherwise all terms are to be construed as they would be by a person skilled in the art.
All technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which this invention belongs unless clearly indicated otherwise.
As used herein the singular forms “a”, “an”, and “the” include plural referents unless the context clearly dictates otherwise. The singular forms “a,” “an,” and “the” may mean “one” but also include plural referents such as “one or more” and “at least one” unless the context clearly dictates otherwise.
As used herein, the term “or” in the claims is used to mean “and/or” unless explicitly indicated to refer to alternatives only or the alternatives are mutually exclusive, although the disclosure supports a definition that refers to only alternatives and “and/or.”
As used herein, the term “about” means plus or minus 10% of the numerical value of the number with which it is being used.
As used herein the term “or combinations thereof” as used herein refers to all permutations and combinations of the listed items preceding the term unless stated otherwise.
The terms “bituminous sands” or “oil sands” refer to a type of petroleum deposit, which typically contains naturally occurring mixtures of sand, clay, water, and a dense, extremely viscous, non-free flowing form of petroleum technically referred to as “bitumen” (or colloquially “tar” due to their similar appearance, odor, and color).
As used herein, the terms “oil sands ore” or “raw oil sands ore” refer to oil sands that have been extracted or mined by an industrial mining process, such as surface mining. Oil sands ore generally comprises mineral ore solids, bitumen, and water. As used herein, the terms “oil sands ore” and “raw oil sands ore” both refer to oil sands ore that has been minimally processed, for example by crushing or particle size reduction methods for further processing by an In-Pit Extraction Process (IPEP) wherein bitumen froth is separated from the oil sands ore by extraction methods.
As used herein, the terms “bitumen extraction” or “In-Pit Extraction Process (IPEP)” refer to an industrial process by which bitumen is separated by extraction from raw oil sands orc. Generally, raw oil sands ore is transferred to a flotation cell, wherein a froth-flotation process is used to separate bitumen from mineral ore solids and water. During this process, oil sands ore is mixed with heated water or steam, optionally also with a process aid to form a slurry, which is transferred to a separation tank. Separation under quiescent conditions results in formation of layers, including (i) a top layer of “bitumen froth”, which comprises bitumen, water and small amount of mineral solids, (ii) a middle layer of middlings (i.e., warm water, fines, residual bitumen), and (iii) a bottom layer of tailings mainly water, mineral solids, and coarse (i.e., warm water, coarse solids, residual bitumen). The bitumen froth, middlings, and tailings are separately withdrawn and the bitumen froth fraction is processed further for recovery of the bitumen. During further processing, the bitumen froth is de-acrated, heated, and diluted with a suitable hydrocarbon solvent to produce diluted bitumen, which is further processed to produce synthetic crude oil and other valuable commodities.
As used herein, the term “aqueous diluent” refers to an aqueous liquid or solution which may be added as a diluent to raw oil sands ore or to a process aid, such as during a froth-flotation process used to separate bitumen from mineral ore solids and water. The aqueous diluent may be added directly to an oils sands ore or may be added to a processing pipe or vessel, such as a flotation cell, to which the oil sands ore is then added. As used herein “aqueous diluent” may refer to water, brine, seawater, or process water comprising an aqueous solution or slurry resulting from any phase of oil sands mining and/or processing, or any combination thereof. The aqueous diluent may also contain one or more process additives.
As used herein, the terms “process water” or “industrial process water” generally refer to any aqueous fluids, solutions, slurries, or dispersions produced during any type of industrial process, for example, processes relating to oil sands, oil, or gas extraction or processing, including recovery, extraction, refining, or waste treatment, chemical manufacturing, polymer manufacturing, pulp and paper industry, waste treatment, water treatment, paints and coatings, food and beverage processing, mining industries, textiles, agriculture, or any portion thereof. An exemplary embodiment of a process water includes an aqueous solution resulting from
The terms “oil sands slurry”, “aqueous suspension”, or “aqueous slurry” generally refer to a heterogeneous mixture of a fluid (e.g., water) that contains solid particles, wherein the solid particles forms a phase separated mixture in which one substance of macroscopically or microscopically dispersed insoluble or soluble particles is suspended throughout another substance, typically a liquid substance. A dispersion has a dispersed phase (the suspended particles) and a continuous phase (the medium of suspension) that arise by phase separation. Macroscopic particles typically separate and settle quickly, while colloids typically do not completely settle or take a long time to settle completely into two separated layers. Exemplary aqueous slurries for the present application include oil sands slurries comprising bitumen, mineral ore, sands, gangue materials, fine solids, such as the clays and silts, dispersed in water, optionally also comprising one or more process aids comprising one or more ionic liquids, chemicals, or polymers. It is understood that any aqueous suspension or aqueous slurry may also contain dissolved or dispersed organic or inorganic materials related to industrial mining applications.
The term, “sand” generally may refer to mineral fractions that may comprise a particle diameter greater than 44 microns.
The term “fines” generally may refer to mineral fractions that may comprise a particle diameter less than 44 microns.
The term “clay” generally may refer to materials having a particle size of less than 2 micrometers which comprise mixtures of fine-grained clay minerals, typically hydrous aluminum silicates with variable amounts of other metals, and clay-sized crystals of other minerals such as quartz, carbonate, and metal oxides. Common clays found in oil sands include illite, kaolinite, and montmorillonite. Less common clays include chlorite and vermiculite.
As used herein, the term “aqueous solution” or “solution” refers to a mixture of water and a water-soluble solute or solutes which are completely dissolved with little to no residual undissolved solute. The solution may be homogenous.
As used herein, the term “bitumen froth” refers to a froth formed during bitumen extraction comprising bitumen, water and small amount of mineral solids, and optionally residual process aids. Average bitumen froth composition consists of 60% bitumen, 30% water, and 10% mineral solids.
As used herein, the terms “froth quality” or “bitumen froth quality” refer to a ratio by mass of recovered bitumen to mineral ore solids in the bitumen froth (i.e., grams bitumen in bitumen froth/grams mineral ore in bitumen froth).
As used herein, the term “bitumen recovery” is used as a metric for bitumen extraction efficiency and is generally determined by calculating a ratio by mass of recovered bitumen to oil sands ore. More specifically, as calculated herein bitumen recovery grams of recovered bitumen/200 grams of raw oil sands ore.
As used herein, the term “process aid” refers to a chemical or polymeric additive for improving froth quality and/or bitumen recovery during a bitumen extraction process. In some embodiments, the process aid is a single process aid. In other embodiments, the process aid is a binary process aid comprising a first process aid and a second process aid. As used herein, the term “binary process aid” refers to a combination of two process aids for improving froth quality and/or bitumen recovery during a bitumen extraction process. In one embodiment the two process aids may be premixed prior to addition to oil sands ore. In other embodiments, the two process aids may be added to the oil sands ore together simultaneously or sequentially in any order.
In some embodiments, the single process aid, the first process aid, and/or the second process aid comprise one or more ionic liquids, one or more dispersants, one or more surfactants, one or more demulsifiers, one or more celluloses, one or more polysaccharides, or any combination thereof.
In one embodiment, the single process aid or binary process aid is added to the aqueous diluent. In another embodiment, the single process aid or binary process aid is added directly to the raw oil sands ore. In another embodiment, the single process aid or binary process aid is diluted with aqueous diluent and then added to the raw oil sands ore. In yet another embodiment, the single process aid or binary process aid is added to oil sands ore after the oil sands ore has been combined with aqueous diluent.
As used herein, the term “ionic liquid” refers to salts with a melting point below 100° C., which are typically liquid at room temperature. Ionic liquids are organic salts, which include two components, namely a cation component and an anion component and are typically prepared by simple mixing of reagents (e.g., cationic and anionic components) in the presence or absence of solvents and/or base and optionally heat, with the respective cationic and anionic components in a desired molar ratio, typically 1:1 for stoichiometric ionic liquids and typically ranging from 3:1 to 1:3 for multivalent ionic liquids. Ionic liquids have been considered as “green” alternatives for molecular solvents and other additives, since there is lower risk of environmental release through the atmosphere due to their low vapor pressures. Ionic liquids tend to be soluble in water and insoluble in non-polar organic solvents. For the present invention, ionic liquids are employed as single process aids or as one or both components of dual process aids for improving froth quality and/or bitumen recovery during a bitumen extraction process.
In some embodiments, said one or more ionic liquids comprise a cationic component and an anionic component comprising a ratio of said cationic to anionic components ranging from 3:1 to 1:1, 2:1 to 1:1, or 2.3:1 to 1.7:1, wherein said cationic component comprises choline or N,N-dimethylbenzylamine (DMBA) and said anionic component comprises succinate, citrate, glutamate, or benzoate.
In other embodiments, said one or more ionic liquids comprise choline succinate, dicholine succinate, choline citrate, dicholine citrate, tricholine citrate, choline glutamate, dicholine glutamate, DMBA benzoate, DMBA succinate, [DMBA]1.7[Succ] comprising a ratio of DMBA to succinate of 1.7:1, di-DMBA succinate, DMBA citrate, di-DMBA citrate, [DMBA]2.3[Cit] comprising a ratio of DMBA to citrate of 2.3:1, or tri-DMBA citrate.
In preferred embodiments, the ionic liquid comprises tricholine citrate as a single process aid or as a component of a dual process aid.
Unless otherwise indicated, the stoichiometry of an ionic liquid may be derived from the nomenclature used herein. For example, choline citrate, dicholine citrate, and tricholine citrate, refer to ionic liquids having ratios of choline to citrate of 1:1, 2:1, and 3:1, respectively. When the stoichiometry involves a non-integer, such stoichiometry may be indicated by an abbreviation. For example, [DMBA]1.7[Succ] comprises a ratio of DMBA to succinate of 1.7:1.
As used herein, the term “surfactant” refers to compounds that lower the surface tension (or interfacial tension) between two liquids, between a gas and a liquid, or between a liquid and a solid. Surfactants may act as detergents, wetting agents, emulsifiers, foaming agents, or dispersants. In certain embodiments, surfactants comprise anionic surfactants, including but not limited to, alcohol propoxy sulfates (APS) and internal olefin sulfonates (IOS); nonionic surfactants, including but not limited to, polyoxyethylene (5) C9-C11 alcohol, and short chain alcohol ethoxylates; and zwitterionic surfactants, including but not limited to, cocamidopropyl betaine, N-[3-(Dimethylamino) propyl] coco amides N-oxides, and sodium capryloamphopropionate.
As used herein, the term “dispersant” refers to compounds, typically a surfactant, that is added to a suspension of solid or liquid particles in a liquid (such as a colloid or emulsion) to improve the separation of the particles and to prevent their settling or clumping. In certain embodiments, dispersants comprise anionic dispersants, including but not limited to, anionic polyacrylate dispersants and polyacrylate-acrylamide copolymer dispersants; and amphoteric dispersants, including but not limited to, amphoteric polyacrylate dispersants.
As used herein, the term “demulsifier” refers to chemicals used as “emulsion breakers”, which are a class of specialty chemicals used to separate emulsions, for example, water in oil. They are commonly used in the processing of crude oil, which is typically produced along with significant quantities of saline water. Suitable demulsifiers for the present invention include polyol block copolymers, alkoxylated alkyl phenol formaldehyde resins, epoxy resin alkoxylates, amine-initiated polyol block copolymers, modified silicone polyethers, and silicone polyethers. In some embodiments, demulsifiers are selected from the list of demulsifiers consisting of resin alkoxylates; one or more polyimine derivative demulsifiers, including but not limited to, ethylenediamine ethoxylates and/or propoxylates, polyethyleneimine polymers; and polyethylene oxide derivatives, including but not limited to, poly(ethylene oxide-b-propylene oxides), poly(ethylene oxide-b-propylene oxide-b-ethylene oxides), and poly(propylene oxide-b-ethylene oxide-b-propylene oxides).
As used herein, the term “cellulose” refers to an organic compound with the formula (C6H10O5)n, which are a polysaccharides consisting of a linear chain of several hundred to many thousands of β(1→4) linked D-glucose units. In some embodiments, celluloses comprise ethyl cellulose and/or hydroxyethyl cellulose.
As used herein, the term “polysaccharide” refers to long-chain polymeric carbohydrates composed of monosaccharide units bound together by glycosidic linkages. In some embodiments, polysaccharides comprise natural and modified starches, chitin, and/or amylopectin.
As used herein, the terms “polymer” or “polymeric additives” and similar terms are used in their ordinary sense as understood by one skilled in the art, and thus may be used herein to refer to or describe a large molecule (or group of such molecules) that may comprise recurring units. Polymers may be formed in various ways, including by polymerizing monomers and/or by chemically modifying one or more recurring units of a precursor polymer. Unless otherwise specified, a polymer may comprise a “homopolymer” that may comprise substantially identical recurring units that may be formed by, for example, polymerizing a particular monomer. Unless otherwise specified, a polymer may also comprise a “copolymer” that may comprise two or more different recurring units that may be formed by, for example, copolymerizing, two or more different monomers, and/or by chemically modifying one or more recurring units of a precursor polymer. Unless otherwise specified, a polymer or copolymer may also comprise a “terpolymer” or a “tetrapolymer” which generally refer to polymers that comprise three, four, or more different recurring monomer units. The term “polymer” as used herein is intended to include both the acid form of the polymer as well as its various salts. Polymers may be amphoteric in nature, that is, containing both anionic and cationic substituents, although not necessarily in the same proportions.
As used herein, the term “ppm” refers to parts per million on the basis of milligrams of solute per liter of solution or slurry (e.g., mg/L).
As used herein, the phrases “% by weight”, “% by mass”, or “% water content by mass” denotes mass of dry mass of a component (e.g., water) per total mass of material in the oil sands ore or bitumen froth, multiplied by 100%.
The present invention relates to methods and process aid compositions for improving froth quality and bitumen recovery during bitumen extraction. In particular, the disclosure provides a method for using multivalent ionic liquids and binary process aid combinations for improving bitumen extraction efficiency and reducing water and mineral solids in bitumen froth. The inventive method utilizes multivalent ionic liquids, particularly tricholine citrate, and binary process aid combinations to improve both froth quality (i.e., ratio by mass of recovered bitumen to mineral ore solids in the bitumen froth) and bitumen recovery (i.e., ratio by mass of recovered bitumen to oil sands ore) during bitumen extraction.
For the present invention, a total of 34 chemicals were investigated including lab-made multivalent nonstoichiometric ionic liquids synthesized in a Kemira R&D laboratory. Various chemical classes were included within the scope of the investigation such as demulsifiers, dispersants, surfactants, flocculants, synthetic and bio-based polymers, and defoamers as well as ionic liquids. These chemicals can affect bitumen-water, bitumen-solid, and/or water-solid interactions which might in turn significantly affect the froth quality and bitumen recovery. Again, all of these chemicals are of interest for only when the dosage level is affordable. Additionally, these chemicals would be detrimental at high concentration due to technical issues related to emulsification and solids suspension.
Among various classes of ionic liquids, two specific classes are of particular interest relevant to this study. The first class is highly polar aprotic ionic liquids which are cholinium salt of di- or tri-carboxylic acid or amino acid which carries multiple negative charges on carboxylate functional groups. The second class is aromatic tertiary amine-based ionic liquids which consist of dimethylbenzylamine (DMBA) and counter-anions with multiple negative charges. Due to relatively low pKa around 9, DMBA-based ionic liquids are non-stoichiometric at neutral pH and molar ratio between cations and anions is controlled by the equilibrium of the proton transfer reaction at given pH. DMBA-based multivalent ionic liquids are Brönsted acidic because acidic proton could exist on either DMBA side or counter-anion side. These two classes could be called multivalent ionic liquids because of the multiple negative charges on the anion. For the present invention, tricholine citrate was one of the chemicals in the multivalent nonstoichiometric ionic liquid class that provided the greatest enhancements in bitumen froth quality and bitumen recovery.
In one aspect, the present invention provides a method for extracting bitumen from oil sands ore to produce a bitumen froth, the method comprising:
In some exemplary embodiments of the method:
In some exemplary embodiments said process aid comprises
In some exemplary embodiments of the method:
In some exemplary embodiments of the method:
In some exemplary embodiments of the method:
In some exemplary embodiments of the method said single process aid comprises tricholine citrate at a dosage ranging from 50-500 ppm, 100-500 ppm, or 200-300 ppm.
In some exemplary embodiments the method results in:
In another aspect, the present invention provides a method for extracting bitumen from oil sands ore to produce a bitumen froth, the method comprising:
In some exemplary embodiments of the method:
In some exemplary embodiments of the method said process aid comprises:
In some exemplary embodiments of the method said process aid comprises:
In some exemplary embodiments of the method:
In some exemplary embodiments the method results in:
In another aspect, the present invention provides a composition comprising:
The examples provided herein are for illustrative purposes so that the invention may be more fully understood. These examples should not be construed as limiting the invention in any way.
In a screening study, 34 chemicals were individually investigated as process aid candidates for bitumen extraction. The candidates were evaluated in bitumen extraction tests to identify process aids for providing improved froth quality (FQ; bitumen-to-solids ratio) and bitumen recovery (BR; grams of bitumen per 200 grams of ore).
Table 1 provides a list of the 34 process aid candidates with wide ranging physicochemical properties, 19 of which were prepared in house and 15 of which were provided by 3rd party chemical suppliers. The candidates belong to 8 chemical classes, e.g., ionic liquids, dispersants, polymers, defoamers, surfactants, demulsifiers, polysaccharides, and cellulose biopolymers, and can be further subdivided into more than 20 subclasses. A photograph image of process aid candidates is shown in
Ionic liquids were synthesized using standard acid-base neutralization reactions. Residual water was not removed from the final products.
Simple stoichiometric ionic liquids (e.g., choline glutamate and N,N-dimethylbenzylamine (DMBA) benzoate) were synthesized by adding stoichiometric amount of acid to base and then dissolving the acid by mixing with or without heat depending on viscosity of the intermediate products. The pH of the final product was adjusted to around 9 for choline products with a quaternary ammonium, but not for DMBA-based products due to a reaction equilibrium of the proton transfer involving the tertiary amine group. Choline glutamate ([Cho][Glu]) was prepared as an equimolar blend of choline hydroxide and glutamic acid.
Nonstoichiometric ionic liquids (e.g., dicholine succinate, tricholine citrate, dicholine glutamate, DMBA succinate, and DMBA citrate) were synthesized as set forth below. Dicholine glutamate ([Cho]2[Glu]) was prepared by dissolving a mole of glutamic acid in two moles of choline hydroxide by gentle mixing at room temperature. Glutamic acid was dissolved in choline hydroxide by mixing on a shaker table for 10 minutes at room temperature followed by mixing at slightly above 45° C. to ensure full dissolution. Dicholine succinate ([Cho]2[Succ]) and dicholine glutamate ([Cho]2[Glu]) were prepared in a similar manner. Tricholine citrate ([Cho]3[Cit]) was prepared in a similar manner using a 3:1 ratio of choline to citrate.
Nonstoichiometric equilibrium reactions were used to prepare DMBA succinate ([DMBA]1.7[Succ]) and DMBA citrate ([DMBA]2.3[Cit]). The final ionic liquids contained a 1.7:1 ratio of DMBA to succinate and a 2.3:1 ratio of DMBA to citrate, respectively. As used throughout the Examples, DMBA succinate refers to [DMBA]1.7[Succ] and DMBA citrate refers to [DMBA]2.3[Cit]. For the remaining ionic liquids, the stoichiometry of the ionic liquid may be derived from the nomenclature used herein. All actual stoichiometries are reflected in the abbreviations.
Two amphoteric dispersants 5040 amp-17 and -30 were synthesized incorporating 1.7 mol % and 3.0 mol % of 2-(Acryloyloxy)ethyl]trimethylammonium chloride (Q9) cationic monomers into sodium polyacrylate. No further characterization was done for the newly synthesized ionic liquids and amphoteric dispersants.
All 3rd party chemicals were diluted to 1% solution in synthetic process water (SPW) brine. The polyimine derivative 1% Kemelix 3515X was dissolved in 25 wt % i-propanol and 75 wt % SPW because of its near-zero solubility in water. All Kemira polymers and Dow Chemical cellulose samples were dissolved in SPW brine at 0.5 wt % concentration due to high viscosity of polymer solutions. The ionic composition of the SPW brine is shown in Table 2.
Process aid candidates were diluted in SPW brine for bitumen extraction test screening according to the Examples set forth below.
A bitumen extraction test apparatus was constructed to accommodate 200 g of oil sands ore. The apparatus comprised a volumetric heat-jacketed extraction cell (600 mL beaker) and 3 inch diameter dispersion blade. An image of the heat-jacketed extraction cells with mechanically driven blades is shown in
Frozen oil sands ore was thawed and homogenized and then used for bitumen extraction tests. In order to reduce variability, the ore samples were conditioned and homogenized prior to testing according to the procedure set forth in steps 1-5 below.
Bitumen Extraction testing was performed using process aid candidates (single and binary combinations) on conditioned oil sands ore samples using the bitumen extraction test apparatus according to the procedure set forth in steps 1-7 below.
Bitumen-water-solids content (% by mass) in the raw oil sands ores (Oil Sands Ore Conditioning Procedure) and in the combined bitumen froth layers (Bitumen Extraction Procedure) was determined by a Soxhlet extraction procedure, wherein bitumen was continuously extracted into toluene. The bitumen-toluene solutions were then captured on a glass fiber filter using a glass filtration apparatus. A key assumption of this procedure was that all components in the bitumen are not volatile, so the mass of bitumen does not change by evaporation of toluene-bitumen solution.
A detailed Soxhlet extraction procedure is set forth in steps 1-6 below
A total of 4 bitumen extraction protocols (BEP) were conducted against 2 oil sands ore batches to identify and optimize single dose process aids and process aid combinations. Two results were used throughout the 4 BEPs to identify and optimize the process aids—froth quality (FQ; bitumen-to-solids ratio) and bitumen recovery (BR; grams of bitumen per 200 grams of ore). Important features of BEP 1-4 are shown in Table 3.
Detailed experimental details and results for BEP 1-4 are presented in the following Examples.
Two batches of oil sands ore were used in the bitumen extraction tests after. Generally, frozen oil sands samples were transported and stored in a freezer. Prior to use in bitumen extraction tests, the ores were thawed and homogenized according to Example 2 (Oil Sands Ore Conditioning Procedure). Raw oil sands ores were analyzed for solids-water-bitumen content in triplicate according to the Soxhlet extraction procedure (Example 2). Results are shown in Table 4.
Soxhlet extraction results indicate highly similar solids-water-bitumen content in Ore batches 1 and 2.
The effect of batch-wise differences of the raw oil sands ore on bitumen extraction results was determined by testing Ore Batches 1 and 2 using the bitumen extraction test procedure (Example 2) with SPW as a blank. This testing was performed to determine the effect of Ore Batch on froth quality (FQ, bitumen-to-solids ratio) and bitumen recovery (BR, grams of bitumen per 200 grams of ore). The experiments were repeated 4 times to better understand the variability within each batch.
Bitumen extraction test results (FQ vs. BR) using SPW brine to extract Ore Batches 1 and 2 are shown in
Results from
For Bitumen Extraction Protocol (BEP) 1, a screening study was conducted, wherein 34 process aid candidates (see Table 1, Example 1) were individually investigated to determine effects on froth quality (FQ, bitumen-to-solids ratio) and bitumen recovery (BR, grams of bitumen per 200 grams of orc). The candidates were evaluated in a bitumen extraction test procedure according to Example 2 at concentrations shown in Table 1.
SPW brine (Table 2) was used as a diluent and as a blank. Testing was performed on Oil Sands Ore Batch 1 (Table 4).
Bitumen extraction test results (FQ vs. BR) for process aid candidates are shown in
The shaded triangle at the center represents the results of blank (SPW brine) samples. Overall, the results display a large variability due to a heterogeneous nature of the oil sands ore and likely human factors as evidenced by approximately ±20% relative standard deviation of the 4 blank samples in both bitumen recovery and froth quality. Using 200 g of orc, bitumen recovery and froth quality of the blanks were 7.9 and 10.4, respectively. It is noteworthy that the FQ of blank samples was higher than the typical industrial FQ of around 6. This could be due to a different test protocol, such as secondary recovery by flotation.
Results from
From the screening test results, the five best process aids were selected by considering performances and structural diversities. Froth quality was considered more important than BR in the selection process, which is the reason for selecting tricholine citrate over DMBA citrate and KG5021 over KG5376. The best process aids are shown in Table 5.
A variability plot displaying collective and average performances of each chemical class is shown in
Results from
On the other hand, 50 ppm polymers were very detrimental to bitumen recovery and froth quality. Average bitumen recovery using 50 ppm polymer was reduced by a factor of 2 and froth quality was also remarkably deteriorated without regard to the structure and charges of polymers. So, it is believed that hetero-flocculation of bitumen and solids caused poor froth quality and at the same time co-precipitation of the hetero-flocs led to significantly lower recovery. It is doubtful flotation could improve froth quality from our test results using polymers. If polymers are considered as an extraction aid under any circumstances, then dosage level should be kept well below 50 ppm.
Results from process aid screening indicate that ionic liquids provided the greatest enhancements in FQ and BR. It was surprisingly found that tricholine citrate (100 ppm dosage) provided the largest increase in FQ of about 20. Ionic liquids DMBA succinate and DMBA citrate provided the 2nd and 3rd highest FQ values. These results provide initial proof of concept that ionic liquids (e.g., tricholine citrate) are effective process aids for enhancing FQ and BR during bitumen extraction procedures.
For BEP 2, binary combinations of the five selected process aids from BEP 1, shown in Table 5, were tested for potential synergistic enhancements in FQ and BR. The binary combinations were evaluated in bitumen extraction test procedures according to Example 2.
First, a total of 9 binary combinations were tested at half-strength, wherein individual components were present at 50% concentration compared to the concentration shown in Table 1. For example, the concentrations of tricholine citrate and KG5021 in the binary component system were 50 ppm and 25 ppm, respectively. Every possible binary combination from Table 5 except 3515X+Cellosize was tested.
Second, a total of 6 additional binary combinations were tested at full-strength, wherein individual components were present at 100% concentration compared to the concentration shown in Table 1. For example, the concentrations of tricholine citrate and KG5021 in the binary component system were 100 ppm and 50 ppm, respectively.
SPW brine (Table 2) was used as a diluent and as a blank. Testing was performed on Oil Sands Ore Batch 1 (Table 4).
Bitumen extraction test results from half-strength (open circles) and full-strength (closed squares) binary combinations are shown in
Results from
These results provide further proof of concept that ionic liquids (e.g., tricholine citrate) are highly effective as process aids for enhancing BR and FQ. The three best combinations (upper-right side in the plot) among 6 data points of
For BEP 3, tricholine citrate was evaluated in bitumen extraction test procedures according to Example 2 at concentrations of 100 ppm, 200 ppm, and 500 ppm. Measurements were duplicated for 100 ppm and triplicated for 200 and 500 ppm.
SPW brine (Table 2) was used as a diluent and as a blank. Testing was performed on Oil Sands Ore Batch 2 (Table 4). Note that, according to results of Example 3, extraction of Ore Batch 2 is generally likely to yield lower FQ and BR results.
Bitumen extraction test results (FQ vs. BR) showing dose dependence of tricholine citrate are shown in
Results from
These results provide further proof of concept that tricholine citrate is highly effective as a process additive for enhancing both FQ and BR. These results also suggest that an effective tricholine citrate dosage for bitumen extraction at industrial scale may be as low as 100 ppm. Dosage may be adjusted as needed, based on ore batch characteristics.
Without being bound to theory, it can be reasoned that tricholine citrate is highly effective as a bitumen extraction process additive for enhancing FQ and BR due to the ability of tricholine citrate to reduce solid-bitumen attractive (or adhesive) forces by increasing negative charges on both solid and bitumen surfaces at given pH.
Wettability of pristine oil sands are known to be water-wet at pH around 8.5 due to the presence of thin water film between bitumen and solid grains. Thus, the improved performance is not exactly a result of wettability alteration in a macroscopic scale. However, there exists oil-wet or mixed-wet fractions on the surfaces of solid grains. Besides, clays could be adhered more easily to bitumen in the presence of divalent cations such as Ca2+ and Mg2+ by electrostatic bridging. The trivalent citrate anions may induce more negatively charged solid and bitumen surfaces as well as sequestrating divalent cations. Overall, the trivalent citrate anions may cause microscopic mixed or oil-wet surface fractions to undergo patch-wise wettability alteration toward more water-wet, thereby improving bitumen recovery and froth quality.
It is not clear how much trivalent citrate anions could penetrate the thin water film between the bitumen and solids, but the significantly improved results strongly suggest that tricholine citrate can effectively suppress the attractive interaction between bitumen and solids to a great extent.
The observation on more suspended solids at higher tricholine citrate concentration could be an additional indirect evidence of strongly negatively charged solid surfaces as shown in
For BEP 4, binary process aid combinations of tricholine citrate (200 ppm or 500 ppm) with DMBA succinate (100 ppm or 200 ppm), KG5021 (50 ppm or 100 ppm), and 3515X (50 ppm or 100 ppm) were evaluated against tricholine citrate alone (200 ppm or 500 ppm) in bitumen extraction test procedures according to Example 2.
Combinatorial concentrations of binary process aid compositions vs tricholine citrate alone are shown in
SPW brine (Table 2) was used as a diluent and as a blank. Testing was performed on Oil Sands Orc Batch 2 (Table 4). Note that, according to results of Example 3, extraction of Ore Batch 2 is generally likely to yield lower FQ and BR results.
Bitumen extraction test results (FQ vs. BR) showing dose dependence of binary process aid combinations of tricholine citrate vs tricholine citrate alone are shown in
Results from
These results provide further proof of concept that ionic liquids (e.g., tricholine citrate) are highly effective as bitumen extraction process aids for enhancing FQ and BR.
Results from
Results from
| Number | Date | Country | Kind |
|---|---|---|---|
| 20236049 | Sep 2023 | FI | national |
| Number | Date | Country | |
|---|---|---|---|
| 63532484 | Aug 2023 | US |
