CA2893988C - Methods of processing bitumen froth - Google Patents
Methods of processing bitumen froth Download PDFInfo
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- CA2893988C CA2893988C CA2893988A CA2893988A CA2893988C CA 2893988 C CA2893988 C CA 2893988C CA 2893988 A CA2893988 A CA 2893988A CA 2893988 A CA2893988 A CA 2893988A CA 2893988 C CA2893988 C CA 2893988C
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- coarse solids
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- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
- C10G1/00—Production of liquid hydrocarbon mixtures from oil-shale, oil-sand, or non-melting solid carbonaceous or similar materials, e.g. wood, coal
- C10G1/04—Production of liquid hydrocarbon mixtures from oil-shale, oil-sand, or non-melting solid carbonaceous or similar materials, e.g. wood, coal by extraction
- C10G1/045—Separation of insoluble materials
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
- B03B—SEPARATING SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS
- B03B9/00—General arrangement of separating plant, e.g. flow sheets
- B03B9/02—General arrangement of separating plant, e.g. flow sheets specially adapted for oil-sand, oil-chalk, oil-shales, ozokerite, bitumen, or the like
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L95/00—Compositions of bituminous materials, e.g. asphalt, tar, pitch
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D21/00—Separation of suspended solid particles from liquids by sedimentation
- B01D21/02—Settling tanks with single outlets for the separated liquid
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D21/00—Separation of suspended solid particles from liquids by sedimentation
- B01D21/24—Feed or discharge mechanisms for settling tanks
- B01D21/2488—Feed or discharge mechanisms for settling tanks bringing about a partial recirculation of the liquid, e.g. for introducing chemical aids
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D21/00—Separation of suspended solid particles from liquids by sedimentation
- B01D21/30—Control equipment
- B01D21/32—Density control of clear liquid or sediment, e.g. optical control ; Control of physical properties
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2221/00—Applications of separation devices
- B01D2221/04—Separation devices for treating liquids from earth drilling, mining
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Life Sciences & Earth Sciences (AREA)
- Organic Chemistry (AREA)
- Polymers & Plastics (AREA)
- Medicinal Chemistry (AREA)
- Health & Medical Sciences (AREA)
- Structural Engineering (AREA)
- Materials Engineering (AREA)
- Wood Science & Technology (AREA)
- General Chemical & Material Sciences (AREA)
- Civil Engineering (AREA)
- Geology (AREA)
- Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)
Abstract
Described is a method of processing a bitumen froth comprising bitumen, water, coarse solids, and fines. The method includes producing a pre-treated bitumen froth by adding paraffinic solvent and coarse solids to the bitumen froth to form agglomerates of precipitated asphaltenes, water, coarse solids, and fines, to assist fines settling and bitumen cleaning; and forming an overflow and an underflow by gravity separating the pre-treated bitumen froth.
Description
METHODS OF PROCESSING BITUMEN FROTH
BACKGROUND
Field of Disclosure [0001] The disclosure relates generally to the field of oil sand processing. More specifically, the disclosure relates to methods of processing bitumen froth.
Description of Related Art
BACKGROUND
Field of Disclosure [0001] The disclosure relates generally to the field of oil sand processing. More specifically, the disclosure relates to methods of processing bitumen froth.
Description of Related Art
[0002] This section is intended to introduce various aspects of the art, which may be associated with the present disclosure. This discussion is believed to assist in providing a framework to facilitate a better understanding of particular aspects of the present disclosure.
Accordingly, it should be understood that this section should be read in this light, and not necessarily as admissions of prior art.
Accordingly, it should be understood that this section should be read in this light, and not necessarily as admissions of prior art.
[0003] Modern society is greatly dependent on the use of hydrocarbon resources for fuels and chemical feedstocks. Hydrocarbons are generally found in subsurface formations that can be termed "reservoirs." Removing hydrocarbons from the reservoirs depends on numerous physical properties of the subsurface formations, such as the permeability of the rock containing the hydrocarbons, the ability of the hydrocarbons to flow through the subsurface formations, and the proportion of hydrocarbons present, among other things.
Easily harvested sources of hydrocarbons are dwindling, leaving less accessible sources to satisfy future energy needs. As the costs of hydrocarbons increase, the less accessible sources become more economically attractive.
[00041 Recently, the harvesting of oil sand to remove heavy oil has become more economical. Hydrocarbon removal from oil sand may be performed by several techniques.
For example, a well can be drilled to an oil sand reservoir and steam, hot air, solvents, or a combination thereof, can be injected to release the hydrocarbons. The released hydrocarbons may be collected by wells and brought to the surface. In another technique, strip or surface mining may be performed to access the oil sand, which can be treated with water, steam or solvents to extract the heavy oil. Where the oil sand is treated with water, the technique may be referred to as water-based extraction (WBE). WBE is a commonly used process to extract bitumen from mined oil sand.
[0005] In an example of WBE, mined oil sands are mixed with water to create a slurry suitable for extraction. Caustic may be added to adjust the slurry pH to a desired level and thereby enhance the efficiency of the separation of bitumen.
100061 Regardless of the type of WBE employed, the extraction process will typically result in the production of a bitumen froth comprising bitumen, water, and solids and a tailings stream comprising solids and water. The tailings stream may consist essentially of coarse solids and some fines and water. A typical composition of bitumen froth may be about 60 weight (wt.) % bitumen, 30 wt. % water, and 10 wt. % solids. A bitumen froth may be, for instance, 40-80 wt. % bitumen, 10-50 wt. % water, and 2-30 wt. % (or 5-15 wt.
%) solids. The water and solids in the froth are considered as contaminants. The contaminants may be substantially eliminated or reduced to a level suitable for feed to an oil refinery or an upgrading facility, respectively. Elimination or reduction of the contaminants may be referred to as a froth treatment process. Elimination or reduction of the contaminants may be achieved by diluting the bitumen froth with a solvent. The solvent may comprise any suitable solvent, such as an organic solvent. For example, the organic solvent may comprise naphtha solvent and/or paraffinic solvent. Diluting the bitumen with solvent (also referred to as dilution) may increase the density differential between bitumen and water and solids.
Diluting the bitumen with solvent may enable the elimination or reduction of contaminants using multi-stage gravity settlers. Use of the multi-stage gravity settlers may result in a "diluted bitumen froth"
and another tailings stream. The another tailings stream may be commonly referred to as the froth treatment tailings. The froth treatment tailings may comprise residual bitumen, residual solvent, solids and water. The froth treatment tailings stream may be further processed to recover residual solvent, for instance in a tailings solvent recovery unit (TSRU). If the solvent is paraffinic solvent, the froth treatment tailings may be referred to as "paraffinic froth treatment tailings" and comprise precipitated asphaltenes.
[0007] One purpose of froth separation is to settle fines so that they form part of the froth treatment tailings (underflow), rather than the diluted bitumen (overflow).
[0008] There is a need for alternative or improved methods of processing bitumen froth.
SUMMARY
[0009] It is an object of the present disclosure to provide methods of processing bitumen froth.
[0010] Described is a method of processing a bitumen froth comprising bitumen, water, coarse solids, and fines. The method includes producing a pre-treated bitumen froth by adding paraffinic solvent and coarse solids to the bitumen froth to form agglomerates of precipitated asphaltenes, water, coarse solids, and fines, to assist fines settling and bitumen cleaning; and forming an overflow and an underflow by gravity separating the pre-treated bitumen froth.
[0011] The foregoing has broadly outlined the features of the present disclosure so that the detailed description that follows may be better understood.
Additional features will also be described herein.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] These and other features, aspects and advantages of the disclosure will become apparent from the following description, appending claims and the accompanying drawings, which are briefly described below.
[0013] Figure 1 is a flow chart of a method of processing bitumen froth.
[0014] Figure 2 is a flow chart of a method of processing bitumen froth.
[0015] Figure 3 is a flow chart of a method of processing bitumen froth.
[0016] It should be noted that the figures are merely examples and no limitations on the scope of the present disclosure are intended thereby. Further, the figures are generally not drawn to scale, but are drafted for purposes of convenience and clarity in illustrating various aspects of the disclosure.
DETAILED DESCRIPTION
[0017] For the purpose of promoting an understanding of the principles of the disclosure, reference will now be made to the features illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the disclosure is thereby intended. Any alterations and further modifications, and any further applications of the principles of the disclosure as described herein are contemplated as would normally occur to one skilled in the art to which the disclosure relates. It will be apparent to those skilled in the relevant art that some features that are not relevant to the present disclosure may not be shown in the drawings for the sake of clarity.
[0018] At the outset, for ease of reference, certain terms used in this application and their meaning as used in this context are set forth below. To the extent a term used herein is not defined below, it should be given the broadest definition persons in the pertinent art have given that term as reflected in at least one printed publication or issued patent. Further, the present processes are not limited by the usage of the terms shown below, as all equivalents, synonyms, new developments and terms or processes that serve the same or a similar purpose are considered to be within the scope of the present disclosure.
[0019] Throughout this disclosure, where a range is used, any number between or inclusive of the range is implied.
[0020] A "hydrocarbon" is an organic compound that primarily includes the elements of hydrogen and carbon, although nitrogen, sulfur, oxygen, metals, or any number of other elements may be present in small amounts. Hydrocarbons generally refer to components found in heavy oil or in oil sand. However, the techniques described are not limited to heavy
Easily harvested sources of hydrocarbons are dwindling, leaving less accessible sources to satisfy future energy needs. As the costs of hydrocarbons increase, the less accessible sources become more economically attractive.
[00041 Recently, the harvesting of oil sand to remove heavy oil has become more economical. Hydrocarbon removal from oil sand may be performed by several techniques.
For example, a well can be drilled to an oil sand reservoir and steam, hot air, solvents, or a combination thereof, can be injected to release the hydrocarbons. The released hydrocarbons may be collected by wells and brought to the surface. In another technique, strip or surface mining may be performed to access the oil sand, which can be treated with water, steam or solvents to extract the heavy oil. Where the oil sand is treated with water, the technique may be referred to as water-based extraction (WBE). WBE is a commonly used process to extract bitumen from mined oil sand.
[0005] In an example of WBE, mined oil sands are mixed with water to create a slurry suitable for extraction. Caustic may be added to adjust the slurry pH to a desired level and thereby enhance the efficiency of the separation of bitumen.
100061 Regardless of the type of WBE employed, the extraction process will typically result in the production of a bitumen froth comprising bitumen, water, and solids and a tailings stream comprising solids and water. The tailings stream may consist essentially of coarse solids and some fines and water. A typical composition of bitumen froth may be about 60 weight (wt.) % bitumen, 30 wt. % water, and 10 wt. % solids. A bitumen froth may be, for instance, 40-80 wt. % bitumen, 10-50 wt. % water, and 2-30 wt. % (or 5-15 wt.
%) solids. The water and solids in the froth are considered as contaminants. The contaminants may be substantially eliminated or reduced to a level suitable for feed to an oil refinery or an upgrading facility, respectively. Elimination or reduction of the contaminants may be referred to as a froth treatment process. Elimination or reduction of the contaminants may be achieved by diluting the bitumen froth with a solvent. The solvent may comprise any suitable solvent, such as an organic solvent. For example, the organic solvent may comprise naphtha solvent and/or paraffinic solvent. Diluting the bitumen with solvent (also referred to as dilution) may increase the density differential between bitumen and water and solids.
Diluting the bitumen with solvent may enable the elimination or reduction of contaminants using multi-stage gravity settlers. Use of the multi-stage gravity settlers may result in a "diluted bitumen froth"
and another tailings stream. The another tailings stream may be commonly referred to as the froth treatment tailings. The froth treatment tailings may comprise residual bitumen, residual solvent, solids and water. The froth treatment tailings stream may be further processed to recover residual solvent, for instance in a tailings solvent recovery unit (TSRU). If the solvent is paraffinic solvent, the froth treatment tailings may be referred to as "paraffinic froth treatment tailings" and comprise precipitated asphaltenes.
[0007] One purpose of froth separation is to settle fines so that they form part of the froth treatment tailings (underflow), rather than the diluted bitumen (overflow).
[0008] There is a need for alternative or improved methods of processing bitumen froth.
SUMMARY
[0009] It is an object of the present disclosure to provide methods of processing bitumen froth.
[0010] Described is a method of processing a bitumen froth comprising bitumen, water, coarse solids, and fines. The method includes producing a pre-treated bitumen froth by adding paraffinic solvent and coarse solids to the bitumen froth to form agglomerates of precipitated asphaltenes, water, coarse solids, and fines, to assist fines settling and bitumen cleaning; and forming an overflow and an underflow by gravity separating the pre-treated bitumen froth.
[0011] The foregoing has broadly outlined the features of the present disclosure so that the detailed description that follows may be better understood.
Additional features will also be described herein.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] These and other features, aspects and advantages of the disclosure will become apparent from the following description, appending claims and the accompanying drawings, which are briefly described below.
[0013] Figure 1 is a flow chart of a method of processing bitumen froth.
[0014] Figure 2 is a flow chart of a method of processing bitumen froth.
[0015] Figure 3 is a flow chart of a method of processing bitumen froth.
[0016] It should be noted that the figures are merely examples and no limitations on the scope of the present disclosure are intended thereby. Further, the figures are generally not drawn to scale, but are drafted for purposes of convenience and clarity in illustrating various aspects of the disclosure.
DETAILED DESCRIPTION
[0017] For the purpose of promoting an understanding of the principles of the disclosure, reference will now be made to the features illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the disclosure is thereby intended. Any alterations and further modifications, and any further applications of the principles of the disclosure as described herein are contemplated as would normally occur to one skilled in the art to which the disclosure relates. It will be apparent to those skilled in the relevant art that some features that are not relevant to the present disclosure may not be shown in the drawings for the sake of clarity.
[0018] At the outset, for ease of reference, certain terms used in this application and their meaning as used in this context are set forth below. To the extent a term used herein is not defined below, it should be given the broadest definition persons in the pertinent art have given that term as reflected in at least one printed publication or issued patent. Further, the present processes are not limited by the usage of the terms shown below, as all equivalents, synonyms, new developments and terms or processes that serve the same or a similar purpose are considered to be within the scope of the present disclosure.
[0019] Throughout this disclosure, where a range is used, any number between or inclusive of the range is implied.
[0020] A "hydrocarbon" is an organic compound that primarily includes the elements of hydrogen and carbon, although nitrogen, sulfur, oxygen, metals, or any number of other elements may be present in small amounts. Hydrocarbons generally refer to components found in heavy oil or in oil sand. However, the techniques described are not limited to heavy
- 4 -oils but may also be used with any number of other reservoirs to improve gravity drainage of liquids. Hydrocarbon compounds may be aliphatic or aromatic, and may be straight chained, branched, or partially or fully cyclic.
[0021] "Bitumen" is a naturally occurring heavy oil material. Generally, it is the hydrocarbon component found in oil sand. Bitumen can vary in composition depending upon the degree of loss of more volatile components. It can vary from a very viscous, tar-like, semi-solid material to solid forms. The hydrocarbon types found in bitumen can include aliphatics, aromatics, resins, and asphaltenes. A typical bitumen might be composed of:
19 weight (wt.) % aliphatics (which can range from 5 wt. % - 30 wt. %, or higher);
19 wt. % asphaltenes (which can range from 5 wt. % - 30 wt. %, or higher);
30 wt. % aromatics (which can range from 15 wt. % - 50 wt. %, or higher);
32 wt. % resins (which can range from 15 wt. % - 50 wt. %, or higher); and some amount of sulfur (which can range in excess of 7 wt. %).
In addition, bitumen can contain some water and nitrogen compounds ranging from less than 0.4 wt. % to in excess of 0.7 wt. %. The percentage of the hydrocarbon found in bitumen can vary. The term "heavy oil" includes bitumen as well as lighter materials that may be found in a sand or carbonate reservoir.
[0022] "Heavy oil" includes oils which are classified by the American Petroleum Institute ("API"), as heavy oils, extra heavy oils, or bitumens. The term "heavy oil" includes bitumen. Heavy oil may have a viscosity of about 1,000 centipoise (cP) or more, 10,000 cP or more, 100,000 cP or more, or 1,000,000 cP or more. In general, a heavy oil has an API gravity between 22.3 API (density of 920 kilograms per meter cubed (kg/m3) or 0.920 grams per centimeter cubed (g/cm3)) and 10.00 API (density of 1,000 kg/m3 or 1 g/cm3).
An extra heavy oil, in general, has an API gravity of less than 10.0 API (density greater than 1,000 kg/m3 or 1 g/cm3). For example, a source of heavy oil includes oil sand or bituminous sand, which is a combination of clay, sand, water and bitumen. The recovery of heavy oils is based on the viscosity decrease of fluids with increasing temperature or solvent concentration. Once the viscosity is reduced, the mobilization of fluid by steam, hot water flooding, or gravity is
[0021] "Bitumen" is a naturally occurring heavy oil material. Generally, it is the hydrocarbon component found in oil sand. Bitumen can vary in composition depending upon the degree of loss of more volatile components. It can vary from a very viscous, tar-like, semi-solid material to solid forms. The hydrocarbon types found in bitumen can include aliphatics, aromatics, resins, and asphaltenes. A typical bitumen might be composed of:
19 weight (wt.) % aliphatics (which can range from 5 wt. % - 30 wt. %, or higher);
19 wt. % asphaltenes (which can range from 5 wt. % - 30 wt. %, or higher);
30 wt. % aromatics (which can range from 15 wt. % - 50 wt. %, or higher);
32 wt. % resins (which can range from 15 wt. % - 50 wt. %, or higher); and some amount of sulfur (which can range in excess of 7 wt. %).
In addition, bitumen can contain some water and nitrogen compounds ranging from less than 0.4 wt. % to in excess of 0.7 wt. %. The percentage of the hydrocarbon found in bitumen can vary. The term "heavy oil" includes bitumen as well as lighter materials that may be found in a sand or carbonate reservoir.
[0022] "Heavy oil" includes oils which are classified by the American Petroleum Institute ("API"), as heavy oils, extra heavy oils, or bitumens. The term "heavy oil" includes bitumen. Heavy oil may have a viscosity of about 1,000 centipoise (cP) or more, 10,000 cP or more, 100,000 cP or more, or 1,000,000 cP or more. In general, a heavy oil has an API gravity between 22.3 API (density of 920 kilograms per meter cubed (kg/m3) or 0.920 grams per centimeter cubed (g/cm3)) and 10.00 API (density of 1,000 kg/m3 or 1 g/cm3).
An extra heavy oil, in general, has an API gravity of less than 10.0 API (density greater than 1,000 kg/m3 or 1 g/cm3). For example, a source of heavy oil includes oil sand or bituminous sand, which is a combination of clay, sand, water and bitumen. The recovery of heavy oils is based on the viscosity decrease of fluids with increasing temperature or solvent concentration. Once the viscosity is reduced, the mobilization of fluid by steam, hot water flooding, or gravity is
- 5 -possible. The reduced viscosity makes the drainage or dissolution quicker and therefore directly contributes to the recovery rate.
[0023] "Fine particles", "fine solids", or "fines" are generally defined as those solids having a size of less than 44 microns ( m), that is, material that passes through a 325 mesh (44 micron).
10024) "Coarse particles" or "coarse solids" are generally defined as those solids having a size of greater than 44 microns (1.1m).
[0025] The term "solvent" as used in the present disclosure should be understood to mean either a single solvent, or a combination of solvents.
[0026] The terms "approximately," "about," "substantially," and similar terms are intended to have a broad meaning in harmony with the common and accepted usage by those of ordinary skill in the art to which the subject matter of this disclosure pertains. It should be understood by those of skill in the art who review this disclosure that these terms are intended to allow a description of certain features described and claimed without restricting the scope of these features to the precise numeral ranges provided. Accordingly, these terms should be interpreted as indicating that insubstantial or inconsequential modifications or alterations of the subject matter described and are considered to be within the scope of the disclosure.
[0027] The articles "the", "a" and "an" are not necessarily limited to mean only one, but rather are inclusive and open ended so as to include, optionally, multiple such elements.
[0028] The term "paraffinic solvent" (also known as aliphatic) as used herein means solvents comprising normal paraffins, isoparaffins or blends thereof in amounts greater than 50 wt. %. Presence of other components such as olefins, aromatics or naphthenes may counteract the function of the paraffinic solvent and hence may be present in an amount of only 1 to 20 wt. % combined, for instance no more than 3 wt. %. The paraffinic solvent may be a C4 to C20 or C4 to C6 paraffinic hydrocarbon solvent or a combination of iso and normal components thereof The paraffinic solvent may comprise n-pentane, iso-pentane, or a
[0023] "Fine particles", "fine solids", or "fines" are generally defined as those solids having a size of less than 44 microns ( m), that is, material that passes through a 325 mesh (44 micron).
10024) "Coarse particles" or "coarse solids" are generally defined as those solids having a size of greater than 44 microns (1.1m).
[0025] The term "solvent" as used in the present disclosure should be understood to mean either a single solvent, or a combination of solvents.
[0026] The terms "approximately," "about," "substantially," and similar terms are intended to have a broad meaning in harmony with the common and accepted usage by those of ordinary skill in the art to which the subject matter of this disclosure pertains. It should be understood by those of skill in the art who review this disclosure that these terms are intended to allow a description of certain features described and claimed without restricting the scope of these features to the precise numeral ranges provided. Accordingly, these terms should be interpreted as indicating that insubstantial or inconsequential modifications or alterations of the subject matter described and are considered to be within the scope of the disclosure.
[0027] The articles "the", "a" and "an" are not necessarily limited to mean only one, but rather are inclusive and open ended so as to include, optionally, multiple such elements.
[0028] The term "paraffinic solvent" (also known as aliphatic) as used herein means solvents comprising normal paraffins, isoparaffins or blends thereof in amounts greater than 50 wt. %. Presence of other components such as olefins, aromatics or naphthenes may counteract the function of the paraffinic solvent and hence may be present in an amount of only 1 to 20 wt. % combined, for instance no more than 3 wt. %. The paraffinic solvent may be a C4 to C20 or C4 to C6 paraffinic hydrocarbon solvent or a combination of iso and normal components thereof The paraffinic solvent may comprise n-pentane, iso-pentane, or a
- 6 -combination thereof. The paraffinic solvent may comprise about 60 wt. %
pentane and about 40 wt. % iso-pentane, with none or less than 20 wt. % of the counteracting components referred above.
[0029] Figures 1 and 2 are flow charts of methods of processing bitumen froth. The bitumen froth (2) may be the result of WBE. For example, mined oil sand may undergo WBE
to form the bitumen froth (2). The bitumen froth (2) may comprise bitumen, water, and solids (coarse solids and fines). As described in the background section, a typical composition of bitumen froth may be about 60 wt. % bitumen, 30 wt. % water, and 10 wt. %
solids and a bitumen froth may be, for instance, 40-80 wt. % bitumen, 10-50 wt. % water, and 2-30 wt. %
(or 5-15 wt. %) solids. These values are not intended to be limiting. The composition of the bitumen froth may vary based on several factors notably including the composition of the mined oil sand from which the bitumen froth is produced.
[0030] The method may comprise producing (102) a pre-treated bitumen froth (8) by adding to the bitumen froth (2), paraffinic solvent (4) and coarse solids (6) to form agglomerates of precipitated asphaltenes, water, coarse solids, and fines, to assist fines settling and bitumen cleaning.
[0031] A purpose of adding the coarse solids (6) to the bitumen froth (2) is to assist fines settling. In particular, it has been discovered that when the coarse solids content in a bitumen froth undergoing paraffinic solvent treatment is too low, agglomerates of asphaltenes, water, coarse solids, and fines will be poorly formed. Instead, free and light asphaltenes, with low settling rate, are formed causing the asphaltenes to exit the settler with the overflow which is not desirable. Such poorly formed agglomerates may also cause foaming downstream in the TSRU and during subsequent tailings treatment. By adding coarse solids, more dense and faster settling agglomerates may form, which can more easily leave processing units, such as settlers, the TSRU, or subsequent tailings treatment. Additionally, increased settling may reduce solvent requirements in the paraffinic froth treatment; that is, the required solvent to bitumen ratio may be reduced. Foaming, due to free asphaltene molecules which act as surfactants, may also be reduced in the TSRU or during subsequent
pentane and about 40 wt. % iso-pentane, with none or less than 20 wt. % of the counteracting components referred above.
[0029] Figures 1 and 2 are flow charts of methods of processing bitumen froth. The bitumen froth (2) may be the result of WBE. For example, mined oil sand may undergo WBE
to form the bitumen froth (2). The bitumen froth (2) may comprise bitumen, water, and solids (coarse solids and fines). As described in the background section, a typical composition of bitumen froth may be about 60 wt. % bitumen, 30 wt. % water, and 10 wt. %
solids and a bitumen froth may be, for instance, 40-80 wt. % bitumen, 10-50 wt. % water, and 2-30 wt. %
(or 5-15 wt. %) solids. These values are not intended to be limiting. The composition of the bitumen froth may vary based on several factors notably including the composition of the mined oil sand from which the bitumen froth is produced.
[0030] The method may comprise producing (102) a pre-treated bitumen froth (8) by adding to the bitumen froth (2), paraffinic solvent (4) and coarse solids (6) to form agglomerates of precipitated asphaltenes, water, coarse solids, and fines, to assist fines settling and bitumen cleaning.
[0031] A purpose of adding the coarse solids (6) to the bitumen froth (2) is to assist fines settling. In particular, it has been discovered that when the coarse solids content in a bitumen froth undergoing paraffinic solvent treatment is too low, agglomerates of asphaltenes, water, coarse solids, and fines will be poorly formed. Instead, free and light asphaltenes, with low settling rate, are formed causing the asphaltenes to exit the settler with the overflow which is not desirable. Such poorly formed agglomerates may also cause foaming downstream in the TSRU and during subsequent tailings treatment. By adding coarse solids, more dense and faster settling agglomerates may form, which can more easily leave processing units, such as settlers, the TSRU, or subsequent tailings treatment. Additionally, increased settling may reduce solvent requirements in the paraffinic froth treatment; that is, the required solvent to bitumen ratio may be reduced. Foaming, due to free asphaltene molecules which act as surfactants, may also be reduced in the TSRU or during subsequent
- 7 -tailings treatment. When foaming occurs in a TSRU, high quality dilution water may be added to reduce such foaming; therefore, if foaming can be reduced, such water addition can also be reduced.
100321 The coarse solids may be added in an amount of at least 0.1 %, at least 0.2 %, at least 0.5 %, at least 1 %, at least 2 %, or at least 5 %, based on a weight of the bitumen froth.
[0033] The coarse solids may be added in an amount sufficient to increase coarse solids content of the pre-treated bitumen froth to above 1 wt. %, to above 2 wt. %, or to above wt. %.
[0034] Sufficient coarse solids (6) may be added to the bitumen froth (2) to achieve a pre-treated bitumen froth (8) comprising 1 to 30 wt. % coarse solids or 5 to 15 wt. % coarse solids.
[0035] The method may include measuring a coarse solids content of the bitumen froth and adding the coarse solids in an amount sufficient to increase coarse solids content of the pre-treated bitumen froth to within a predetermined range, such as I to 30 wt. %, or 5 to wt. %.
[0036] Sufficient paraffinic solvent (4) may be added to the bitumen froth (2) to achieve a pre-treated bitumen froth (8) comprising a solvent to bitumen ratio of 0.5 to 2, or 0.7 to 1.5, or 0.8 to 1.2, on a weight basis. The solvent to bitumen ratio is expressed with a presumptive denominator value of one; therefore, a ratio of 0.5 to 2 could equally be expressed as 0.5:1 to 2:1.
[0037] The added coarse solids (6) may have an affinity for precipitated asphaltenes to assist agglomeration. The added coarse solids (6) may comprise sand. In oil sand extraction, sand is abundant. The sand may be, for instance, from beach sand or coarse sand tailings. The sand may be screened to a desired size. The added coarse solids (6) may comprise carbon black. The added coarse solids (6) may comprise a zeolite. The added coarse solids (6) may
100321 The coarse solids may be added in an amount of at least 0.1 %, at least 0.2 %, at least 0.5 %, at least 1 %, at least 2 %, or at least 5 %, based on a weight of the bitumen froth.
[0033] The coarse solids may be added in an amount sufficient to increase coarse solids content of the pre-treated bitumen froth to above 1 wt. %, to above 2 wt. %, or to above wt. %.
[0034] Sufficient coarse solids (6) may be added to the bitumen froth (2) to achieve a pre-treated bitumen froth (8) comprising 1 to 30 wt. % coarse solids or 5 to 15 wt. % coarse solids.
[0035] The method may include measuring a coarse solids content of the bitumen froth and adding the coarse solids in an amount sufficient to increase coarse solids content of the pre-treated bitumen froth to within a predetermined range, such as I to 30 wt. %, or 5 to wt. %.
[0036] Sufficient paraffinic solvent (4) may be added to the bitumen froth (2) to achieve a pre-treated bitumen froth (8) comprising a solvent to bitumen ratio of 0.5 to 2, or 0.7 to 1.5, or 0.8 to 1.2, on a weight basis. The solvent to bitumen ratio is expressed with a presumptive denominator value of one; therefore, a ratio of 0.5 to 2 could equally be expressed as 0.5:1 to 2:1.
[0037] The added coarse solids (6) may have an affinity for precipitated asphaltenes to assist agglomeration. The added coarse solids (6) may comprise sand. In oil sand extraction, sand is abundant. The sand may be, for instance, from beach sand or coarse sand tailings. The sand may be screened to a desired size. The added coarse solids (6) may comprise carbon black. The added coarse solids (6) may comprise a zeolite. The added coarse solids (6) may
- 8 -comprise a combination of sand, carbon black, and a zeolite. The added coarse solids may go through pre-processing, such as size screening or washing with solvents, water, or chemicals, for instance to increase their hydrophobicity.
[0038] The coarse solids (6) may be added before the paraffinic solvent (4). The paraffinic solvent (4) may be added before the coarse solids (6). Both the coarse solids (6) and the paraffinic solvent (4) may be added to the bitumen froth (2) to form the pre-treated bitumen froth (8) prior to introduction into the settler (10). Figure 2 illustrates the paraffinic solvent and coarse solids being added to the bitumen froth separately. It will be understood that they may alternatively be added to the bitumen froth as a combined stream.
[0039] The method may comprise forming (104) an overflow (12) and an underflow (14) by gravity separating the pre-treated bitumen froth (8). The overflow (12) has a higher liquid content (by weight) and a lower solid content (by weight) than the underflow (14). The gravity separation may be performed in a settler (10). The overflow may comprise 1 to 5 wt.
% fines. The overflow may have less than 10 wt. %, or less than 8 wt. %, asphaltenes.
[0040] The settler (10) may be any suitable gravity settler. The settler (10) may comprise a vertical tank (10a) above a conical bottom (10b). The underflow (14) may be withdrawn from the bottom of the settler (10). The bottom of the settler (10) may be within the conical bottom (10b). Where two or more settlers are used, they may be arranged in series or in parallel. Settlers used in froth separation are commonly referred to as froth separation units (FSUs).
[0041] The overflow (12) may comprise bitumen and solvent. Solvent may be recovered from the overflow (12). For example, the overflow (12) may be passed through a solvent recovery unit (SRU) or other suitable apparatus in which the solvent is flashed off and condensed in a condenser associated with the solvent flashing apparatus and recycled/reused in the process. The SRU may be any suitable SRU, such as but not limited to a fractionation vessel. The underflow (14) and additional paraffinic solvent (16), which may be fresh solvent, may be passed to a second settler (18) as seen in Figure 3. A second overflow (20) from the
[0038] The coarse solids (6) may be added before the paraffinic solvent (4). The paraffinic solvent (4) may be added before the coarse solids (6). Both the coarse solids (6) and the paraffinic solvent (4) may be added to the bitumen froth (2) to form the pre-treated bitumen froth (8) prior to introduction into the settler (10). Figure 2 illustrates the paraffinic solvent and coarse solids being added to the bitumen froth separately. It will be understood that they may alternatively be added to the bitumen froth as a combined stream.
[0039] The method may comprise forming (104) an overflow (12) and an underflow (14) by gravity separating the pre-treated bitumen froth (8). The overflow (12) has a higher liquid content (by weight) and a lower solid content (by weight) than the underflow (14). The gravity separation may be performed in a settler (10). The overflow may comprise 1 to 5 wt.
% fines. The overflow may have less than 10 wt. %, or less than 8 wt. %, asphaltenes.
[0040] The settler (10) may be any suitable gravity settler. The settler (10) may comprise a vertical tank (10a) above a conical bottom (10b). The underflow (14) may be withdrawn from the bottom of the settler (10). The bottom of the settler (10) may be within the conical bottom (10b). Where two or more settlers are used, they may be arranged in series or in parallel. Settlers used in froth separation are commonly referred to as froth separation units (FSUs).
[0041] The overflow (12) may comprise bitumen and solvent. Solvent may be recovered from the overflow (12). For example, the overflow (12) may be passed through a solvent recovery unit (SRU) or other suitable apparatus in which the solvent is flashed off and condensed in a condenser associated with the solvent flashing apparatus and recycled/reused in the process. The SRU may be any suitable SRU, such as but not limited to a fractionation vessel. The underflow (14) and additional paraffinic solvent (16), which may be fresh solvent, may be passed to a second settler (18) as seen in Figure 3. A second overflow (20) from the
- 9 -second settler (18) may be recycled for use as the source of paraffinic solvent (4). A second underflow (22) from the second settler may be processed to remove paraffinic solvent, for instance in a tailings solvent recovery unit (TSRU) (24). Steam or an inert gas (26) may be introduced into the TSRU (24) to vaporize and remove solvent (28). The recovered solvent (28) may be recycled (not shown) to the process. The TSRU tailings (30) may be directed to a tailings deposition area or processed further in tailings processing facilities.
100421 Without making any promise, the method may be used for reducing gravity settling time and/or for reducing downstream water requirements in recovering the paraffinic solvent from the underflow in a tailings solvent recovery unit.
[0043] The method may include producing a pre-treated bitumen froth by adding paraffinic solvent and coarse solids to the bitumen froth to form agglomerates of precipitated asphaltenes, water, coarse solids, and fines, to assist fines settling, wherein the coarse solids are added in an amount of at least 0.1 % based on a weight of the bitumen froth; forming an overflow and an underflow by gravity separating the pre-treated bitumen froth;
adding additional paraffinic solvent to the underflow and gravity separating a resulting stream to produce a second underflow and a second overflow; recycling the second overflow as a source of the paraffinic solvent; and removing at least a portion of the paraffinic solvent from the second underflow by vaporization in a tailings solvent recovery unit using steam or an inert gas.
100441 It should be understood that numerous changes, modifications, and alternatives to the preceding disclosure can be made without departing from the scope of the disclosure.
The preceding description, therefore, is not meant to limit the scope of the disclosure. Rather, the scope of the disclosure is to be determined only by the appended claims and their equivalents. It is also contemplated that structures and features in the present examples can be altered, rearranged, substituted, deleted, duplicated, combined, or added to each other.
100421 Without making any promise, the method may be used for reducing gravity settling time and/or for reducing downstream water requirements in recovering the paraffinic solvent from the underflow in a tailings solvent recovery unit.
[0043] The method may include producing a pre-treated bitumen froth by adding paraffinic solvent and coarse solids to the bitumen froth to form agglomerates of precipitated asphaltenes, water, coarse solids, and fines, to assist fines settling, wherein the coarse solids are added in an amount of at least 0.1 % based on a weight of the bitumen froth; forming an overflow and an underflow by gravity separating the pre-treated bitumen froth;
adding additional paraffinic solvent to the underflow and gravity separating a resulting stream to produce a second underflow and a second overflow; recycling the second overflow as a source of the paraffinic solvent; and removing at least a portion of the paraffinic solvent from the second underflow by vaporization in a tailings solvent recovery unit using steam or an inert gas.
100441 It should be understood that numerous changes, modifications, and alternatives to the preceding disclosure can be made without departing from the scope of the disclosure.
The preceding description, therefore, is not meant to limit the scope of the disclosure. Rather, the scope of the disclosure is to be determined only by the appended claims and their equivalents. It is also contemplated that structures and features in the present examples can be altered, rearranged, substituted, deleted, duplicated, combined, or added to each other.
- 10 -
Claims (33)
1. A method of processing a bitumen froth comprising bitumen, water, coarse solids, and fines, the method comprising:
a) producing a pre-treated bitumen froth by adding paraffinic solvent and coarse solids to the bitumen froth to form agglomerates of precipitated asphaltenes, water, coarse solids, and fines, to assist fines settling and bitumen cleaning;
and b) forming an overflow and an underflow by gravity separating the pre-treated bitumen froth.
a) producing a pre-treated bitumen froth by adding paraffinic solvent and coarse solids to the bitumen froth to form agglomerates of precipitated asphaltenes, water, coarse solids, and fines, to assist fines settling and bitumen cleaning;
and b) forming an overflow and an underflow by gravity separating the pre-treated bitumen froth.
2. The method of claim 1, wherein the coarse solids are added in an amount of at least 0.1 % based on a weight of the bitumen froth.
3. The method of claim 1, wherein the coarse solids are added in an amount of at least 0.2 % based on a weight of the bitumen froth.
4. The method of claim 1, wherein the coarse solids are added in an amount of at least 0.5 % based on a weight of the bitumen froth.
5. The method of claim 1, wherein the coarse solids are added in an amount of at least 1 % based on a weight of the bitumen froth.
6. The method of claim 1, wherein the coarse solids are added in an amount of at least 2 % based on a weight of the bitumen froth.
7. The method of claim 1, wherein the coarse solids are added in an amount of at least % based on a weight of the bitumen froth.
8. The method of claim 1, wherein the coarse solids are added in an amount sufficient to increase coarse solids content of the pre-treated bitumen froth to above 1 wt.
%.
%.
9. The method of claim 1, wherein the coarse solids are added in an amount sufficient to increase coarse solids content of the pre-treated bitumen froth to above 2 wt.
%.
%.
10. The method of claim 1, wherein the coarse solids are added in an amount sufficient to increase coarse solids content of the pre-treated bitumen froth to above 5 wt.
%.
%.
11. The method of any one of claims 1 to 8, wherein the coarse solids are added in an amount sufficient to increase coarse solids content of the pre-treated bitumen froth to between 1 and 30 wt. %.
12. The method of any one of claims 1 to 10, wherein the coarse solids are added in an amount sufficient to increase coarse solids content of the pre-treated bitumen froth to between 5 and 15 wt. %.
13. The method of claim 1, further comprising measuring a coarse solids content of the bitumen froth and adding the coarse solids in an amount sufficient to increase coarse solids content of the pre-treated bitumen froth to within a predetermined range.
14. The method of claim 13, wherein the predetermined range is 1 to 30 wt.
%.
%.
15. The method of claim 13, wherein the predetermined range is 5 to 15 wt.
%.
%.
16. The method of any one of claims 1 to 15, wherein the coarse solids are added before the paraffinic solvent.
17. The method of any one of claims 1 to 15, wherein the paraffinic solvent is added before the coarse solids.
18. The method of any one of claims 1 to 15, wherein the added coarse solids have an affinity for precipitated asphaltenes.
19. The method of claim 18, further comprising pre-treating the added coarse solids to increased their hydrophobicity.
20. The method of any one of claims 1 to 19, wherein the added coarse solids comprise sand.
21. The method of any one of claims 1 to 19, wherein the added coarse solids comprise carbon black.
22. The method of any one of claims 1 to 19, wherein the added coarse solids comprise a zeolite.
23. The method of any one of claims 1 to 22, wherein the overflow comprises 1 to 5 wt. %
fines.
fines.
24. The method of any one of claims 1 to 23, wherein step b) is effected in a settler.
25. The method of claim 24, wherein the settler is a froth separation unit.
26. The method of any one of claims 1 to 25, wherein the bitumen froth is a product of water based extraction (WBE) of mined oil sand.
27. The method of any one of claims 1 to 26, further comprising:
c) adding additional paraffinic solvent to the underflow and gravity separating a resulting stream to produce a second underflow and a second overflow.
c) adding additional paraffinic solvent to the underflow and gravity separating a resulting stream to produce a second underflow and a second overflow.
28. The method of any one of claims 1 to 27, wherein the overflow comprises less than wt. % asphaltenes.
29. The method of any one of claims 1 to 27, wherein the overflow comprises less than 8 wt. % asphaltenes.
30. The method of any one of claims 1 to 29, wherein a sufficient amount of paraffinic solvent is added to achieve a pre-treated bitumen froth having a paraffinic solvent to bitumen ratio of 0.5:1 to 2:1, on a weight basis.
31. The method of any one of claims 1 to 29, wherein a sufficient amount of paraffinic solvent is added to achieve a pre-treated bitumen froth having a paraffinic solvent to bitumen ratio of 0.7:1 to 1.5:1, on a weight basis.
32. The method of any one of claims 1 to 29, wherein a sufficient amount of paraffinic solvent is added to achieve a pre-treated bitumen froth having a paraffinic solvent to bitumen ratio of 0.8:1 to 1.2:1, on a weight basis.
33. A method of processing a bitumen froth comprising bitumen, water, coarse solids, and fines, the method comprising:
a) producing a pre-treated bitumen froth by adding paraffinic solvent and coarse solids to the bitumen froth to form agglomerates of precipitated asphaltenes, water, coarse solids, and fines, to assist fines settling, wherein the coarse solids are added in an amount of at least 0.1 % based on a weight of the bitumen froth;
b) forming an overflow and an underflow by gravity separating the pre-treated bitumen froth;
c) adding additional paraffinic solvent to the underflow and gravity separating a resulting stream to produce a second underflow and a second overflow;
d) recycling the second overflow into step a) as a source of the paraffinic solvent;
and e) removing at least a portion of the paraffinic solvent from the second underflow by vaporization in a tailings solvent recovery unit using steam or an inert gas.
a) producing a pre-treated bitumen froth by adding paraffinic solvent and coarse solids to the bitumen froth to form agglomerates of precipitated asphaltenes, water, coarse solids, and fines, to assist fines settling, wherein the coarse solids are added in an amount of at least 0.1 % based on a weight of the bitumen froth;
b) forming an overflow and an underflow by gravity separating the pre-treated bitumen froth;
c) adding additional paraffinic solvent to the underflow and gravity separating a resulting stream to produce a second underflow and a second overflow;
d) recycling the second overflow into step a) as a source of the paraffinic solvent;
and e) removing at least a portion of the paraffinic solvent from the second underflow by vaporization in a tailings solvent recovery unit using steam or an inert gas.
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|---|---|---|---|
| CA2893988A CA2893988C (en) | 2015-06-10 | 2015-06-10 | Methods of processing bitumen froth |
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|---|---|
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| CA2893988C true CA2893988C (en) | 2016-09-20 |
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