Integrated Processes For Recovery of Hydrocarbon From Oil Sands

Abstract

Processes are described for extracting hydrocarbon from a mineable deposit, such as bitumen from oil sands. The integration of solvent-based extraction processes with aqueous extraction processes is described. In one embodiment, water is removed from an aqueous bituminous feed that is then directed into a solvent-based extraction process. In another embodiment, a stream produced through solvent extraction is directed into a water-based extraction process. In the solvent-based extraction processes, agglomeration of fines may be employed to simplify subsequent solid-liquid separation. The process permits recovery of hydrocarbon that has conventionally may have been too difficult to recover from oil sands processing, and thus has previously been lost. Advantageously, a fungible product can be formed more efficiently according to certain integrated processes described herein.

1 . A process for extracting bitumen from oil sands into a bitumen-rich stream, the process comprising:
 (a) separating bitumen from oil sands by addition of water to form a bitumen-enhanced stream and a bitumen-lean stream;   (b) mixing the bitumen-lean stream with additional oil sands to form a mixed stream;   (c) adding solvent to the mixed stream to extract bitumen from the mixed stream into the solvent, thereby forming a bitumen-depleted stream and an extracted bitumen stream; and   (d) mixing the extracted bitumen stream with the bitumen-enhanced stream to form a bitumen-rich stream.   
     
     
         2 . The process of  claim 1 , wherein:
 separating bitumen from oil sands comprises a water-based extraction process, and/or   adding solvent to the mixed stream comprises a solvent-based extraction process.   
     
     
         3 . The process of  claim 1 , wherein:
 the bitumen-enhanced stream comprises froth, sales bitumen product, FSU overflow, or SRU underflow; and/or   the bitumen-lean stream comprises middlings, primary separation tailings, flotation tailings, mature fine tailings, a reject stream from a slurry preparation system of a water-based extraction process, or froth treatment tailings, wherein said froth treatment tailings may optionally be derived from a froth separation unit underflow or from a tailings solvent recovery unit.   
     
     
         4 . The process of  claim 1 , wherein the bitumen-lean stream is partially dewatered before mixing with additional oil sands so that the bitumen-lean stream contains 40% water by weight or less. 
     
     
         5 . The process of  claim 1 , wherein solvent is removed from the extracted bitumen stream before mixing with the bitumen-enhanced stream to form the bitumen-rich stream. 
     
     
         6 . The process of  claim 1 , wherein the bitumen-rich stream is processed to remove residual solids and water therefrom to produce a product cleaned bitumen. 
     
     
         7 . The process of  claim 6 , wherein: the bitumen-rich stream is processed in a froth treatment unit of a water-based extraction process to produce a product cleaned bitumen, said froth treatment optionally comprising paraffinic froth treatment, producing a fungible bitumen product. 
     
     
         8 . The process of  claim 7 , wherein:
 the bitumen-rich stream is mixed with the bitumen-lean stream before being directed to paraffinic froth treatment, and optionally the bitumen-lean stream is partially dewatered before being mixed with the bitumen-rich stream.   
     
     
         9 . The process of  claim 3 , wherein the bitumen-enhanced stream comprises the sales bitumen product, and wherein mixing the extracted bitumen stream with the sales bitumen product yields a bitumen-rich stream that is fungible. 
     
     
         10 . The process of  claim 1 , wherein the bitumen-depleted stream comprises agglomerated fines, said fines being agglomerated from the mixed stream after adding solvent to the mixed stream, forming agglomerates, which may optionally be washed on a belt filter using countercurrent washing. 
     
     
         11 . The process of  claim 1 , wherein separating bitumen from oil sands comprises a water-based extraction process and adding solvent to the mixed stream comprises a solvent-based extraction process, and wherein solvent recovery of the water-based extraction process and solvent recovery of the solvent-based extraction process are consolidated. 
     
     
         12 . A process for pre-treating an aqueous hydrocarbon-containing feed for a downstream solvent-based extraction process for bitumen recovery, said aqueous hydrocarbon-containing feed comprising from 50 wt % to 95 wt % water, from 0.1 wt % to 10 wt % bitumen, and from 5 wt % to 50 wt % solids, wherein said solids comprise fines, the process comprising:
 removing water from the aqueous hydrocarbon-containing feed to produce an effluent comprising 40 wt % water or less; and   providing the effluent to the downstream solvent-based extraction process for bitumen recovery, wherein said downstream solvent-based extraction process comprises fines agglomeration.   
     
     
         13 . The process according to  claim 12 , wherein removing water from the aqueous hydrocarbon-containing feed comprises:
 flowing the aqueous hydrocarbon-containing feed into a primary water separation system to remove water from the aqueous hydrocarbon-containing feed, producing a reduced-water stream of from 30 wt % to 60 wt % solids, and recycled water; and   removing water from the reduced-water stream using a secondary water separation system to produce an effluent comprising 40 wt % water or less;   wherein the primary water separation system optionally comprises a clarifier, a settler, a thickener or a cyclone; and   wherein solvent or a flocculant is optionally mixed with the aqueous hydrocarbon-containing feed prior to water separation.   
     
     
         14 . The process of  claim 12 , wherein the aqueous hydrocarbon-containing feed is produced from a water-based extraction process wherein a flocculant or coagulant is used to induce aggregation of fines and hydrocarbons within the water-based extraction process. 
     
     
         15 . The process of  claim 13 , wherein solvent is mixed with the aqueous hydrocarbon-containing feed prior to water separation, said solvent having bitumen entrained therein for a solvent:bitumen ratio of less than about 2:1, said solvent optionally comprising a low boiling point cycloalkane solvent. 
     
     
         16 . The process of  claim 13 , wherein:
 the secondary water separation system comprises a centrifuge with filtering capacity, a shale shaker, a vacuum belt filter, or one or more clarifiers;   the aqueous hydrocarbon-containing feed comprises effluent of a froth separation unit; and/or   the aqueous hydrocarbon-containing feed comprises tailings from a tailings solvent recovery unit.   
     
     
         17 . The process of  claim 12 , additionally comprising a process for recovery of bitumen, wherein the downstream solvent-based extraction process comprises:
 combining a first solvent with the effluent and a bituminous feed from oil sands to form an initial slurry; separating the initial slurry into a fine solids stream and a coarse solids stream; agglomerating solids from the fine solids stream to form an agglomerated slurry comprising agglomerates and a low solids bitumen extract; separating the low solids bitumen extract from the agglomerated slurry; mixing a second solvent with the low solids bitumen extract to form a solvent-bitumen low solids mixture, the second solvent having a similar or lower boiling point than the first solvent; subjecting the mixture to gravity separation to produce a high grade bitumen extract and a low grade bitumen extract; and recovering the first and second solvent from the high grade bitumen extract, leaving a high grade bitumen product; or   combining a first solvent with the effluent and a bituminous feed from oil sands to form an initial slurry; agglomerating solids from the initial slurry to form an agglomerated slurry comprising agglomerates and a low solids bitumen extract; separating the low solids bitumen extract from the agglomerated slurry; mixing a second solvent with the low solids bitumen extract to form a solvent-bitumen low solids mixture, the second solvent having a similar or lower boiling point than the first solvent, subjecting the mixture to gravity separation to produce a high grade bitumen extract and a low grade bitumen extract; and recovering the first and second solvent from the high grade bitumen extract, leaving a high grade bitumen product; wherein the ratio of first solvent to bitumen in the initial slurry is selected to avoid precipitation of asphaltenes during agglomeration.   
     
     
         18 . A system for pre-treating an aqueous hydrocarbon-containing feed for a downstream solvent-based extraction process for bitumen recovery according to the process of  claim 12 , said aqueous hydrocarbon-containing feed comprising from 50 wt % to 95 wt % water, from 0.1 wt % to 10 wt % bitumen, and from 5 wt % to 50 wt % solids, wherein said solids comprise fines, the system comprising:
 a dewatering unit for removing water from the aqueous hydrocarbon-containing feed to produce an effluent comprising 40 wt % water or less; and   a conduit for providing the effluent to a downstream solvent-based extraction process comprising fines agglomeration to recover bitumen;   wherein the dewatering unit optionally comprises: a primary water separation system to remove water from the aqueous hydrocarbon-containing feed, producing a reduced-water stream and recycled; and a secondary water separation system for receiving the reduced-water stream and removing water therefrom to produce an effluent comprising 40 wt % water or less.   
     
     
         19 . A process for recovering hydrocarbon from a tailings stream from a paraffinic froth treatment process, the process comprising:
 (a) accessing a hydrocarbon-containing froth treatment tailings stream from a paraffinic froth treatment process;   (b) combining the froth treatment tailings stream with a solvent and additional oil sands to form a slurry;   (c) agitating the slurry to dissolve hydrocarbon into the solvent and to agglomerate fines within the slurry;   (d) separating the extracted hydrocarbon from the agglomerated fines to form a low solids extracted hydrocarbon stream and an extracted tailings stream; and   (e) recovering the solvent from the extracted tailings stream.   
     
     
         20 . The process of  claim 19 , wherein:
 the froth treatment tailings stream is derived from a froth separation unit underflow of the paraffinic froth treatment process;   the froth treatment tailings stream is derived from a tailings solvent recovery unit of the paraffinic froth treatment process; or   the froth treatment tailings stream is partially dewatered to form a dewatered tailings stream before combining with the solvent and additional oil sands; said froth treatment tailings stream being dewatered to less than 40 wt % water.   
     
     
         21 . The process of  claim 19 , wherein:
 the slurry formed by combining the froth treatment tailings stream with the solvent and the additional oil sands has a water content of from 5 wt % to 25 wt %;   the solvent comprises an aromatic solvent such as toluene or benzene; or the solvent comprises a cycloalkane; and/or   the solvent comprises entrained bitumen, and said entrained bitumen is initially present in the solvent at 10 wt % or greater.   
     
     
         22 . The process of  claim 19 , wherein separating the extracted hydrocarbon from the agglomerated fines comprises washing agglomerated fines on a belt filter, optionally by countercurrent washing of agglomerated fines with progressively cleaner solvent. 
     
     
         23 . A process for recovering bitumen from oil sands, the process comprising:
 (a) extracting bitumen from oil sands in a water-based extraction process to form a bitumen-enhanced stream and a bitumen-lean stream;   (b) mixing the bitumen-enhanced stream with a solvent to form an extraction liquor;   (c) mixing the extraction liquor with additional oil sands to form a slurry comprising solids and bitumen extract;   (d) separating the solids from the slurry to form a low solids bitumen extract; and   (e) recovering solvent from the low solids bitumen extract to form a solvent extracted bitumen product.   
     
     
         24 . The process of  claim 23 , wherein:
 the oil sands extracted in the water-based extraction process are oil sands of a high to medium bitumen content and a low to medium fines content;   the additional oil sands are oil sands of low to medium bitumen content and of high to medium fines content; and/or   the water-based extraction process used to produce the bitumen-enhanced stream employs a flocculant or a coagulant to induce aggregation of fines and hydrocarbon within the water-based extraction process.   
     
     
         25 . The process of  claim 23 , wherein:
 the water used in the water-based extraction process comprises a sodium ion content of 1000 wppm or greater, on a weight basis;   the water used in the water-based extraction process has a calcium ion content of 100 wppm or greater, on a weight basis; and/or   the water used in the water-based extraction process has a pH of less than 8.   
     
     
         26 . The process of  claim 23 , wherein:
 the bitumen-enhanced stream has bitumen to solids ratio greater than the oil sands;   the bitumen-enhanced stream has a bitumen to solids ratio of greater than 0.5:1;   the bitumen-enhanced stream has a bitumen content of 50 wt % or greater; and/or   the bitumen-enhanced stream has a water content of 30 wt % or less.   
     
     
         27 . The process of  claim 23 , wherein the bitumen-enhanced stream is bitumen froth from the water-based extraction process. 
     
     
         28 . The process of  claim 23 , further comprising:
 partially dewatering the bitumen-enhanced stream prior to mixing with the solvent; and/or   partially dewatering the extraction liquor prior to mixing with additional oil sands.   
     
     
         29 . The process of  claim 23 , wherein the solvent extracted bitumen product comprises between 0.1 to about 2 wt % solids on a bitumen basis. 
     
     
         30 . The process of  claim 23 , further comprising directing the solvent extracted bitumen product to a product cleaning stage to produce a fungible bitumen product; wherein the product cleaning stage optionally comprises gas flotation, membrane filtration, or a combination thereof, and wherein the fungible bitumen product comprises less than 300 wppm solids on a bitumen basis. 
     
     
         31 . The process of  claim 23 , further comprising dewatering of the bitumen-lean stream. 
     
     
         32 . A process for removing solids from oil sands, the process comprising:
 (a) forming an oil sands slurry by mixing the oil sands with a first solvent, wherein the amount of first solvent added is greater than 10 wt % of the oil sands;   (b) separating a majority of the solids from the oil sands slurry, forming a solids-rich stream and a bitumen-rich stream, wherein the bitumen-rich stream comprises residual solids;   (c) emulsifying the bitumen-rich stream with a water-containing stream to form a hydrocarbon-external emulsion, wherein hydrocarbons form an external phase of the emulsion;   (d) mixing the hydrocarbon-external emulsion with a deasphalting solvent in sufficient quantity to cause some asphaltene precipitation, wherein precipitated asphaltenes adhere to at least a portion of the residual solids and to water droplets; and   (e) separating the precipitated asphaltenes from the hydrocarbon-external emulsion, thereby removing residual solids and water droplets adhering to the precipitated asphaltenes and forming a cleaned hydrocarbon product.   
     
     
         33 . The process of  claim 32 , wherein:
 the solvents are removed from the cleaned hydrocarbon product to form a fungible bitumen product;   the majority of the deasphalting solvent comprises C3-C6 components, on a weight basis; and/or   wherein the first solvent and deasphalting solvent are the same.   
     
     
         34 . The process of  claim 32 , wherein the water-containing stream comprises process water, bitumen froth, middlings, flotation tailings, froth treatment tailings, deasphalting unit tailings, or mixtures thereof. 
     
     
         35 . The process of  claim 32 , wherein the hydrocarbon-external emulsion formed comprises a hydrocarbon dominated phase as overflow and an underflow with water as the dominant fluid. 
     
     
         36 . The process of  claim 32 , further comprising:
 removing the first solvent from the bitumen-rich stream prior to emulsifying the bitumen-rich stream with the water-containing stream; and/or.   adding the deasphalting solvent to the bitumen-rich stream prior to emulsifying the bitumen-rich stream with the water-containing stream, wherein the deasphalting solvent is added to the bitumen-rich stream in an amount that is not sufficient to precipitate asphaltenes.   
     
     
         37 . The process of  claim 32 , further comprising removing the first solvent from the hydrocarbon-external emulsion prior to mixing the hydrocarbon-external emulsion with the deasphalting solvent. 
     
     
         38 . The process of  claim 32 , wherein:
 separating a majority of the solids from the oil sands slurry comprises agglomeration of fines; and/or   the bitumen-rich stream comprises between 0.1 to about 2 wt % solids on a bitumen basis.   
     
     
         39 . The method of  claim 32 , wherein mixing the hydrocarbon-external emulsion with a deasphalting solvent occurs in a deasphalting unit, and
 wherein the deasphalting unit is optionally a paraffinic froth treatment unit of a water-based extraction process, and/or the deasphalting unit comprises primary separation and secondary separation; and   wherein the water-containing stream provides a sufficient amount of water to allow water to be the dominant fluid in a settling phase when the emulsion is deasphalted.   
     
     
         40 . The process of  claim 39 , wherein deasphalting in the deasphalting unit comprises:
 mixing the deasphalting solvent with the hydrocarbon-external emulsion and directing the mixture into a primary settling vessel to produce a primary overflow and a primary underflow; and   introducing the primary overflow into a solvent recovery unit to produce the cleaned bitumen product and to recover the deasphalting solvent;   wherein the primary underflow is introduced into a secondary settling vessel with the deasphalting solvent from the solvent recovery unit, to produce deasphalting solvent and a secondary underflow.   
     
     
         41 . The process of  claim 40 , wherein:
 the deasphalting solvent from the secondary settling vessel is the deasphalting solvent that is mixed with the hydrocarbon-external emulsion; and/or   the ratio of the deasphalting solvent to bitumen of the secondary settling vessel is about 10:1 or greater to minimize bitumen lost in the secondary underflow.   
     
     
         42 . The process of  claim 40 , further comprising:
 adding water, additives, or a combination thereof, to the primary settling vessel;   introducing the secondary underflow into a tailings solvent recovery unit to produce tailings and to recover deasphalting solvent; and/or   recycling the deasphalting solvent from the tailings solvent recovery unit into the secondary settling vessel.   
     
     
         43 . A process for removing solids from oil sands comprising bitumen and solids, the process comprising:
 (a) mixing oil sands with a first solvent to form an oil sands slurry, wherein the amount of the first solvent added is greater than 10 wt % of the oil sands;   (b) separating a majority of the solids from the oil sands slurry to form a solids-rich stream and an initial bitumen-rich stream, wherein the initial bitumen-rich stream comprises residual solids;   (c) removing the first solvent from the initial bitumen-rich stream to form a solvent depleted bitumen-rich stream;   (d) directing at least a portion of the solvent-depleted bitumen-rich stream to a paraffinic froth treatment process of a water-based extraction process; and   (e) deriving a fungible bitumen product from the paraffinic froth treatment process.   
     
     
         44 . The process of  claim 43 , additionally comprising:
 mixing oil sands with water, wherein the amount of water added is greater than 50 wt % of the oil sands, and forming bitumen froth, wherein the bitumen froth comprises bitumen, solids and water; and   directing the bitumen froth and a second solvent to the paraffinic froth treatment process of the water-based extraction process.   
     
     
         45 . The process of  claim 43 , wherein:
 the residual solids within the initial bitumen-rich stream is less than 2 wt % of the mass content of the initial bitumen-rich stream; and/or   the second solvent is a paraffinic solvent or a mixture thereof.   
     
     
         46 . The process of  claim 43 , wherein the paraffinic froth treatment process occurs within a first froth settling unit (FSU 1) and a second froth settling unit (FSU 2), and optionally:
 the solvent-depleted bitumen-rich stream is mixed with the bitumen froth before being directed to the FSU 1;   the solvent-depleted bitumen-rich stream is mixed with overflow of FSU 1, and the second solvent is removed from the overflow of FSU 1 prior to mixing with the solvent-depleted bitumen-rich stream;   the solvent-depleted bitumen-rich stream is mixed with the underflow of FSU 1; or   the solvent-depleted bitumen-rich stream is mixed with the overflow of FSU 2.   
     
     
         47 . The process of  claim 43 , further comprising adding bridging liquid to the oil sands slurry to agglomerate fines within the oil sands slurry, optionally wherein the bridging liquid is water. 
     
     
         48 . A process for recovering hydrocarbon from oil sands, the process comprising:
 (a) contacting a first oil sands ore with a solvent to form a solvent-based slurry comprising solids and a bitumen extract;   (b) separating the solids from the solvent-based slurry to produce a low solids bitumen extract;   (c) removing solvent from the low solids bitumen extract to form a solvent extracted bitumen product;   (d) contacting a second oil sands ore with water to form an aqueous slurry;   (e) mixing the solvent extracted bitumen product with the aqueous slurry to form a bitumen enriched slurry; and   (f) recovering bitumen from the bitumen enriched second slurry.   
     
     
         49 . The process of  claim 48 , wherein:
 the aqueous slurry comprises a water-based extraction stream upstream of primary separation in a water-based extraction process;   the aqueous slurry comprises a middlings stream of primary separation in a water-based extraction process; or   the aqueous slurry comprises a tailings stream of primary, secondary or tertiary separation in a water-based extraction process.   
     
     
         50 . The process of  claim 48 , wherein:
 the solvent extracted bitumen product is mixed with process water prior to mixing with the aqueous slurry, optionally wherein the process water is used as a bridging liquid to agglomerate solids within the solvent-based slurry.   
     
     
         51 . The process of  claim 48 , wherein recovering bitumen occurs within a settling vessel, or within flotation cells. 
     
     
         52 . The process of  claim 48 , wherein mixing the solvent extracted bitumen product with the aqueous slurry occurs upstream of froth treatment, optionally within a hydrotransport pipeline. 
     
     
         53 . A process for extracting hydrocarbon from oil sands ore, the process comprising:
 (a) contacting the ore with a first solvent to form a first slurry comprising solids and a bitumen extract;   (b) separating the bitumen extract from the first slurry to form solvent wet tailings comprised of the solids and the first solvent;   (c) removing the first solvent from the solvent wet tailings to form dry tailings; and   (d) combining said dry tailings with water wet tailings produced from a water-based extraction process to form strengthened tailings,   wherein the dry tailings comprise a water content of less than 15 wt % and the water wet tailings comprise a water content of more than 25 wt %.   
     
     
         54 . The process of  claim 53 , wherein the solvent wet tailings are washed with a second solvent producing washed solids, and optionally:
 the first solvent and second solvent are removed from the washed solids to form the dry tailings; and/or   the second solvent is a paraffinic solvent of carbon number C7 or less.   
     
     
         55 . The process of  claim 53 , wherein a bridging liquid is added to the first slurry so as to agglomerate some or all the solids within the first slurry to form an agglomerated slurry comprising agglomerated solids and a bitumen extract;
 wherein the bridging liquid is optionally process water, optionally comprising dissolved salts, water-soluble adhesives, and/or emulsion type adhesives.   
     
     
         56 . The process of  claim 53 , further comprising:
 adding water-soluble adhesives and/or emulsion type adhesives to the solvent wet tailings; and/or   adding water-soluble adhesives and/or emulsion type adhesives to the dry tailings.   
     
     
         57 . The process of  claim 53 , wherein the dry tailings:
 comprise precipitated asphaltenes;   are heat treated at a temperatures greater than 500° C.; and/or   are sintered at a high temperature prior to forming strengthened tailings.   
     
     
         58 . The process of  claim 53 , wherein the water wet tailings are:
 thickened fine tailings from a water-based extraction process, and optionally comprise the underflow from a high rate or paste thickener;   mature fine tailings from a water-based extraction process; or   non-segregating tailings from a water-based extraction process;   optionally wherein said water wet tailings are partially dewatered prior to mixing with dry tailings.   
     
     
         59 . The process of  claim 58 , wherein the non-segregating tailings comprise a mixture of thickened fine tailings and coarse tailings produced within a water-based extraction process;
 or comprise a mixture of mature fine tailings and coarse tailings produced within a water-based extraction process.   
     
     
         60 . The process of  claim 53 , wherein the strengthened tailings have a strength of 5 kPa or greater. 
     
     
         61 . The process of  claim 53 , wherein:
 combining the dry tailings with water wet tailings comprises spraying the water wet tailings onto the dry tailings; or   combining the dry tailings with water wet tailings comprises mixing to form agglomerates.   
     
     
         62 . The process of  claim 53 , wherein:
 the dry tailings are used for mine construction material, mine refill, or direct reclamation; and/or   the strengthened tailings are treated with a coagulant, and/or are treated to lower the pH of the strengthened tailings.