Method for extracting bitumen from an oil sand stream (Shell)

CATEGORY: BITUMEN 
Method for extracting bitumen from an oil sand stream (Shell)

Type	Patent
Inventor	Ingmar Hubertus Josephina Ploemen
Inventor	Gerhardus Willem Colenbrander
URL	Free Full Text Source:  http://www.google.com/patents/US20140083332
Assignee	Shell Canada Energy,
Patent Number	US20140083332 A1
Issue Date	Mar 27, 2014
Abstract	The present invention provides a method for extracting bitumen from an oil sand stream, the method comprising at least the steps of, a) providing an oil sand stream; b) contacting the oil sand stream with a liquid comprising a solvent to obtain a solvent-diluted oil sand slurry; c) separating the oil sand slurry to obtain a first solids-depleted stream and a first solids-enriched stream; d) filtering the first solids-enriched stream obtained in step c) to obtain bitumen-depleted sand and at least a first filtrate; e) separating at least a part of the first filtrate to obtain a second solids-depleted stream and a second solids-enriched stream; and f) contacting at least a part of the second solids-enriched stream from step e) with solvent to obtain a solvent-diluted second solids-enriched stream; and g) separating the solvent-diluted second solids-enriched stream to obtain a third solids-enriched stream and a third solids-depleted stream. BACKGROUND The present invention relates to a method for extracting bitumen from an oil sand. Various methods have been proposed in the past for the recovery of bitumen (sometimes referred to as “tar” or “bituminous material”) from oil sands as found in various locations throughout the world and in particular in Canada such as in the Athabasca district in Alberta and in the United States such as in the Utah oil sands. Typically, oil sand (also known as “bituminous sand” or “tar sand”) comprises a mixture of bitumen (in this context also known as “crude bitumen”, a semi-solid form of crude oil; also known as “extremely heavy crude oil”), sand, clay minerals and water. Usually, oil sand contains about 5 to 25 wt. % bitumen (as meant according to the present invention), about 1 to 13 wt. % water, the remainder being sand and clay minerals. As an example, it has been proposed and practiced at commercial scale to recover the bitumen content from the oil sand by mixing the oil sand with water and separating the bitumen froth from the aqueous slurry formed. Disadvantages of such aqueous extraction processes are the need for extremely large quantities of process water (typically drawn from natural sources) and issues with removing the bitumen from the aqueous phase (whilst emulsions are being formed) and removing water from the bitumen-depleted sand (and clay). Other methods have proposed non-aqueous extraction processes to reduce the need for large quantities of process water. Example of such a non-aqueous extraction process are disclosed in e.g. U.S. Pat. No. 3,475,318, US 2009/0301937 and WO 2011/021092, the teaching of which is hereby incorporated by reference. There is a continuous desire to improve the process efficiency in methods for extracting bitumen from an oil sand stream. It is an object of the invention to provide a more efficient method for extracting bitumen from an oil sand stream. It is a further object of the invention to provide an alternative non-aqueous solvent based extraction process for extracting bitumen from an oil sand.

Method for extracting bitumen from an oil sand stream (Shell)

CATEGORY: BITUMEN 
Method for extracting bitumen from an oil sand stream (Shell)

Type	Patent
Inventor	Ingmar Hubertus Josephina Ploemen
Inventor	Gerhardus Willem Colenbrander
Inventor	Anjana Kalpesh BHALODI
URL	Free Full Text Source:  http://www.google.com/patents/US20140083332
Assignee	Shell Canada Energy,
Patent Number	US20140083332 A1
Issue Date	Mar 27, 2014
Abstract	The present invention provides a method for extracting bitumen from an oil sand stream, the method comprising at least the steps of, a) providing an oil sand stream; b) contacting the oil sand stream with a liquid comprising a solvent to obtain a solvent-diluted oil sand slurry; c) separating the oil sand slurry to obtain a first solids-depleted stream and a first solids-enriched stream; d) filtering the first solids-enriched stream obtained in step c) to obtain bitumen-depleted sand and at least a first filtrate; e) separating at least a part of the first filtrate to obtain a second solids-depleted stream and a second solids-enriched stream; and f) contacting at least a part of the second solids-enriched stream from step e) with solvent to obtain a solvent-diluted second solids-enriched stream; and g) separating the solvent-diluted second solids-enriched stream to obtain a third solids-enriched stream and a third solids-depleted stream. BACKGROUND The present invention relates to a method for extracting bitumen from an oil sand. Various methods have been proposed in the past for the recovery of bitumen (sometimes referred to as “tar” or “bituminous material”) from oil sands as found in various locations throughout the world and in particular in Canada such as in the Athabasca district in Alberta and in the United States such as in the Utah oil sands. Typically, oil sand (also known as “bituminous sand” or “tar sand”) comprises a mixture of bitumen (in this context also known as “crude bitumen”, a semi-solid form of crude oil; also known as “extremely heavy crude oil”), sand, clay minerals and water. Usually, oil sand contains about 5 to 25 wt. % bitumen (as meant according to the present invention), about 1 to 13 wt. % water, the remainder being sand and clay minerals. As an example, it has been proposed and practiced at commercial scale to recover the bitumen content from the oil sand by mixing the oil sand with water and separating the bitumen froth from the aqueous slurry formed. Disadvantages of such aqueous extraction processes are the need for extremely large quantities of process water (typically drawn from natural sources) and issues with removing the bitumen from the aqueous phase (whilst emulsions are being formed) and removing water from the bitumen-depleted sand (and clay). Other methods have proposed non-aqueous extraction processes to reduce the need for large quantities of process water. Example of such a non-aqueous extraction process are disclosed in e.g. U.S. Pat. No. 3,475,318, US 2009/0301937 and WO 2011/021092, the teaching of which is hereby incorporated by reference. There is a continuous desire to improve the process efficiency in methods for extracting bitumen from an oil sand stream. It is an object of the present invention to meet this desire and to provide a more efficient method for extracting bitumen from an oil sand stream. It is a further object of the present invention to provide an alternative non-aqueous solvent based extraction process for extracting bitumen from an oil sand. One or more of the above or other objects may be achieved according to the present invention by providing a method for extracting bitumen from an oil sand stream, the method comprising at least the steps of: (a) providing an oil sand stream; (b) contacting the oil sand stream with a liquid comprising a solvent thereby obtaining a solvent-diluted oil sand slurry; (c) separating the solvent-diluted oil sand slurry, thereby obtaining a first solids-depleted stream and a first solids-enriched stream; (d) filtering the first solids-enriched stream obtained in step (c), thereby obtaining bitumen-depleted sand and at least a first filtrate; (e) separating at least a part of the first filtrate thereby obtaining a second solids-depleted stream and a second solids-enriched stream; and (f) contacting at least a part of the second solids-enriched stream as obtained in step (e) with solvent thereby obtaining a solvent-diluted second solids-enriched stream; and (g) separating the solvent-diluted second solids-enriched stream thereby obtaining a third solids-enriched stream and a third solids-depleted stream. It has now surprisingly been found according to the present invention that bitumen can be extracted from an oil sand stream in a surprisingly efficient and simple manner. A further advantage of the present invention is that no tailings ponds are required because no water needs to be used in the bitumen extraction process. Also, by further processing the second solids-enriched stream as obtained in step (e), more bitumen is recovered thereby increasing the overall bitumen recovery of the extraction process. According to the present invention, the providing of the oil sand in step (a) can be done in various ways. Typically, before contacting the dry oil sand (which may contain some water being present in the oil sand) with the solvent the oil sand lumps are reduced in size, e.g. by crushing, breaking and/or grinding, to below a desired size upper limit. Experience in large scale operations shows that the achievable size upper limit for such size reduction is currently about 8 inch. The contacting in step (b) of the oil sand with the liquid comprising a solvent thereby obtaining a solvent-diluted oil sand slurry is not limited in any way either. As an example, the liquid may be added before, during or after the size-reducing step (if available) of the oil sand. Further size reduction in the presence of the liquid (comprising the solvent) may be performed; part of the size reduction may take place by dissolution of bitumen present in the oil sand (bitumen acts as a bonding agent for the oil sand lumps), but further size reduction e.g. by using screens and/or again crushers, breaker or grinders may be performed, if desired. Typically, the solvent forms the major part of the liquid and is preferably present in an amount of from 40 wt. % up to 100 wt. %, preferably above 60 wt. %, more preferably above 70 wt. %, even more preferably above 80 or even above 90 wt. %, based on the amount of the liquid. The liquid may contain some solids, for example if the liquid is recycled from a downstream part of the process. The solvent as used in the method of the present invention may be selected from a wide variety of solvents, including aromatic hydrocarbon solvents and saturated or unsaturated aliphatic (i.e. non-aromatic) hydrocarbon solvents; aliphatic hydrocarbon solvents may include linear, branched or cyclic alkanes and alkenes and mixtures thereof. Preferably, the solvent in step (b) is a non-aqueous solvent and preferably comprises an aliphatic hydrocarbon having from 3 to 9 carbon atoms per molecule, more preferably from 4 to 7 carbons per molecule, or a combination thereof. Especially suitable solvents are saturated aliphatic hydrocarbons such as propane, butane, pentane, hexane, heptane, octane and nonane (including isomers thereof), in particular butane, pentane, hexane and heptane. It is preferred that the solvent in step (b) comprises at least 90 wt. % of the aliphatic hydrocarbon having from 3 to 9 carbon atoms per molecule, preferably at least 95 wt. %. Also, it is preferred that in step (b) substantially no aromatic solvent (such as toluene or benzene) is present, i.e. less than 5 wt. %, preferably less than 1 wt. %. Further it is preferred that a single solvent is used as this avoids the need for a distillation unit or the like to separate solvents. Also it is preferred that no water is added during the contacting in step (b). However, the oil sand may intrinsically contain some water; preferably the solvent-diluted slurry comprises less than 15 wt. % water, preferably less than 10 wt. %.

Method for extracting bitumen from an oil sand stream (Shell)

CATEGORY: BITUMEN
Method for extracting bitumen from an oil sand stream (Shell)

Type	Patent
Inventor	Ingmar Hubertus Josephina Ploemen
Inventor	Gerhardus Willem Colenbrander
Inventor	Anjana Kalpesh BHALODI
URL	Free Full Text Source:  http://www.google.com/patents/US20140083332
Assignee	Shell Canada Energy,
Patent Number	US20140083332 A1
Issue Date	Mar 27, 2014
Abstract	The present invention provides a method for extracting bitumen from an oil sand stream, the method comprising at least the steps of, a) providing an oil sand stream; b) contacting the oil sand stream with a liquid comprising a solvent to obtain a solvent-diluted oil sand slurry; c) separating the oil sand slurry to obtain a first solids-depleted stream and a first solids-enriched stream; d) filtering the first solids-enriched stream obtained in step c) to obtain bitumen-depleted sand and at least a first filtrate; e) separating at least a part of the first filtrate to obtain a second solids-depleted stream and a second solids-enriched stream; and f) contacting at least a part of the second solids-enriched stream from step e) with solvent to obtain a solvent-diluted second solids-enriched stream; and g) separating the solvent-diluted second solids-enriched stream to obtain a third solids-enriched stream and a third solids-depleted stream. BACKGROUND The present invention relates to a method for extracting bitumen from an oil sand. Various methods have been proposed in the past for the recovery of bitumen (sometimes referred to as “tar” or “bituminous material”) from oil sands as found in various locations throughout the world and in particular in Canada such as in the Athabasca district in Alberta and in the United States such as in the Utah oil sands. Typically, oil sand (also known as “bituminous sand” or “tar sand”) comprises a mixture of bitumen (in this context also known as “crude bitumen”, a semi-solid form of crude oil; also known as “extremely heavy crude oil”), sand, clay minerals and water. Usually, oil sand contains about 5 to 25 wt. % bitumen (as meant according to the present invention), about 1 to 13 wt. % water, the remainder being sand and clay minerals. As an example, it has been proposed and practiced at commercial scale to recover the bitumen content from the oil sand by mixing the oil sand with water and separating the bitumen froth from the aqueous slurry formed. Disadvantages of such aqueous extraction processes are the need for extremely large quantities of process water (typically drawn from natural sources) and issues with removing the bitumen from the aqueous phase (whilst emulsions are being formed) and removing water from the bitumen-depleted sand (and clay). Other methods have proposed non-aqueous extraction processes to reduce the need for large quantities of process water. Example of such a non-aqueous extraction process are disclosed in e.g. U.S. Pat. No. 3,475,318, US 2009/0301937 and WO 2011/021092, the teaching of which is hereby incorporated by reference. There is a continuous desire to improve the process efficiency in methods for extracting bitumen from an oil sand stream. It is an object of the present invention to meet this desire and to provide a more efficient method for extracting bitumen from an oil sand stream. It is a further object of the present invention to provide an alternative non-aqueous solvent based extraction process for extracting bitumen from an oil sand. One or more of the above or other objects may be achieved according to the present invention by providing a method for extracting bitumen from an oil sand stream, the method comprising at least the steps of: (a) providing an oil sand stream; (b) contacting the oil sand stream with a liquid comprising a solvent thereby obtaining a solvent-diluted oil sand slurry; (c) separating the solvent-diluted oil sand slurry, thereby obtaining a first solids-depleted stream and a first solids-enriched stream; (d) filtering the first solids-enriched stream obtained in step (c), thereby obtaining bitumen-depleted sand and at least a first filtrate; (e) separating at least a part of the first filtrate thereby obtaining a second solids-depleted stream and a second solids-enriched stream; and (f) contacting at least a part of the second solids-enriched stream as obtained in step (e) with solvent thereby obtaining a solvent-diluted second solids-enriched stream; and (g) separating the solvent-diluted second solids-enriched stream thereby obtaining a third solids-enriched stream and a third solids-depleted stream. It has now surprisingly been found according to the present invention that bitumen can be extracted from an oil sand stream in a surprisingly efficient and simple manner. A further advantage of the present invention is that no tailings ponds are required because no water needs to be used in the bitumen extraction process. Also, by further processing the second solids-enriched stream as obtained in step (e), more bitumen is recovered thereby increasing the overall bitumen recovery of the extraction process. According to the present invention, the providing of the oil sand in step (a) can be done in various ways. Typically, before contacting the dry oil sand (which may contain some water being present in the oil sand) with the solvent the oil sand lumps are reduced in size, e.g. by crushing, breaking and/or grinding, to below a desired size upper limit. Experience in large scale operations shows that the achievable size upper limit for such size reduction is currently about 8 inch. The contacting in step (b) of the oil sand with the liquid comprising a solvent thereby obtaining a solvent-diluted oil sand slurry is not limited in any way either. As an example, the liquid may be added before, during or after the size-reducing step (if available) of the oil sand. Further size reduction in the presence of the liquid (comprising the solvent) may be performed; part of the size reduction may take place by dissolution of bitumen present in the oil sand (bitumen acts as a bonding agent for the oil sand lumps), but further size reduction e.g. by using screens and/or again crushers, breaker or grinders may be performed, if desired. Typically, the solvent forms the major part of the liquid and is preferably present in an amount of from 40 wt. % up to 100 wt. %, preferably above 60 wt. %, more preferably above 70 wt. %, even more preferably above 80 or even above 90 wt. %, based on the amount of the liquid. The liquid may contain some solids, for example if the liquid is recycled from a downstream part of the process. The solvent as used in the method of the present invention may be selected from a wide variety of solvents, including aromatic hydrocarbon solvents and saturated or unsaturated aliphatic (i.e. non-aromatic) hydrocarbon solvents; aliphatic hydrocarbon solvents may include linear, branched or cyclic alkanes and alkenes and mixtures thereof. Preferably, the solvent in step (b) is a non-aqueous solvent and preferably comprises an aliphatic hydrocarbon having from 3 to 9 carbon atoms per molecule, more preferably from 4 to 7 carbons per molecule, or a combination thereof. Especially suitable solvents are saturated aliphatic hydrocarbons such as propane, butane, pentane, hexane, heptane, octane and nonane (including isomers thereof), in particular butane, pentane, hexane and heptane. It is preferred that the solvent in step (b) comprises at least 90 wt. % of the aliphatic hydrocarbon having from 3 to 9 carbon atoms per molecule, preferably at least 95 wt. %. Also, it is preferred that in step (b) substantially no aromatic solvent (such as toluene or benzene) is present, i.e. less than 5 wt. %, preferably less than 1 wt. %. Further it is preferred that a single solvent is used as this avoids the need for a distillation unit or the like to separate solvents. Also it is preferred that no water is added during the contacting in step (b). However, the oil sand may intrinsically contain some water; preferably the solvent-diluted slurry comprises less than 15 wt. % water, preferably less than 10 wt. %.

Kinetics of Vapor-Phase Cracking of Bitumen-Derived Heavy Gas Oil

CATEGORY: HEAVY GAS OIL
Energy Fuels, 2013, 27 (6), pp 2999–3005, DOI: 10.1021/ef4009407
Kinetics of Vapor-Phase Cracking of Bitumen-Derived Heavy Gas Oil
Weida Bu and Murray R. Gray *
murray.gray@ualberta.ca
Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 2V4, Canada
Abstract
Reports a study of the kinetics of vapor-phase cracking of bitumen-derived heavy gas oil and the quality of the resulting liquid products at temperatures of 600–700 °C. Researchers examined light ends components using gas chromatography. They characterized the quality of the liquid product with simulated distillation, elemental analysis, and ¹³C nuclear magnetic resonance spectroscopy.
The coke yield was negligible at less than 2%, which is consistent with vapor-phase cracking. The yields of C₂–C₃ olefins were 2–16 wt %, while the yields of C₂–C₃ alkanes ranged from 0.2 to 1.0 wt %. The hydrogen content of the liquid product decreased significantly with conversion, corresponding to an increase of the aromatic carbon content.
Full Text Source (Subscription or Fee): http://pubs.acs.org/doi/abs/10.1021/ef4009407

Characterization of Acidic Compounds in Heavy Petroleum Resid by Fractionation and Negative-Ion Electrospray Ionization Fourier Transform Ion Cyclotron Resonance Mass Spectrometry Analysis

Energy Fuels, 2013, 27 (8), pp 4555–4563, DOI: 10.1021/ef400459m, Publication Date (Web): June 25, 2013
Characterization of Acidic Compounds in Heavy Petroleum Resid by Fractionation and Negative-Ion Electrospray Ionization Fourier Transform Ion Cyclotron Resonance Mass Spectrometry Analysis
Litao Wang †, Chen He †, Yahe Zhang †, Suoqi Zhao *†, Keng H. Chung ‡, Chunming Xu †, Chang Samuel Hsu †§, and Quan Shi *†
sqzhao@cup.edu.cn
sq@cup.edu.cn
† State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Beijing 102249, People’s Republic of China
‡ Well Resources Incorporated, 3919-149A Street, Edmonton, Alberta T6R 1J8, Canada
§ Department of Chemical and Biomedical Engineering, Florida State University, Tallahassee, Florida 32310, United States
Abstract
While negative-ion electrospray ionization (ESI) makes possible the direct mass spectrographic analysis of phenols, naphthenic acids, and neutral nitrogen compounds in petroleum fractions without prefractionation, ESI results offer meager quantitative and structural information about the analyte. The composition of acidic compounds in heavy oil remains unclear.
Researchers employed extrography to fractionate oilsands bitumen-derived vacuum-topped bitumen (VTB) and its maltene and asphaltene fractions into multiple subfractions. They analyzed  olecular compositions of acidic functional compounds in the VTB. Its subfractions were analyzed by negative-ion ESI Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). Extrographic separation was a necessary step to isolate acidic compounds of various acidities and/or polarities in vacuum resid fractions to achieve a systematic analysis. Results revealed that the O2 class species in VTB were highly condensed phenols and carboxylic acids.
The maltene fraction contained most of the less condensed naphthenic acids. The asphaltene fraction, on the other hand, contained highly condensed carboxylic acids and phenolic compounds with a bouble-bond equivalent (DBE) higher than 6. The presence of acids had no significant impact on the yield of asphaltenes in n-C7 solvent precipitation. Acid-free asphaltene fractions, which account for more than 90 wt % of the asphaltenes, cannot be ionized by negative-ion ESI.
Full Text Source (Subscription or Fee): http://pubs.acs.org/doi/abs/10.1021/ef400459m

Catalytic Cracking Reaction of Heavy Oil in the Presence of Cerium Oxide Nanoparticles in Supercritical Water

Energy Fuels, 2013, 27 (8), pp 4624–4631, DOI: 10.1021/ef400855k, Publication Date (Web): July 19, 2013
Catalytic Cracking Reaction of Heavy Oil in the Presence of Cerium Oxide Nanoparticles in Supercritical Water
Mehdi Dejhosseini †‡, Tsutomu Aida , Masaru Watanabe §, Seiichi Takami ‡, Daisuke Hojo #, Nobuaki Aoki #, Toshihiko Arita ‡, Atsushi Kishita , and Tadafumi Adschiri *‡#
ajiri@tagen.tohoku.ac.jp
† Graduate School of Engineering, Tohoku University, 6-6 Aramaki Aza Aoba, Aoba-ku, Sendai 980-8579, Japan
‡ Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
§ Research Center of Supercritical Fluid Technology, Tohoku University, 6-6-11 Aoba, Aramaki, Aoba-ku, Sendai 980-8579, Japan
New Industry Creation Hatchery Center, Tohoku University, 6-6-10 Aramaki Aza Aoba, Aoba-ku, Sendai 980-8579, Japan
Department of Environmental Science and Technology, Tohoku University, Aramaki, Aoba-ku, Sendai 980-8579, Japan
# World Premier International Research Center-Advanced Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
Abstract
Researchers conducted catalytic cracking of Canadian oil sand bitumen in supercritical water to understand the effect of CeO2 nanoparticles. They conducted cracking at 723 K to promote a redox reaction between the water, bitumen, and catalyst for the production of hydrogen and oxygen. CeO2 with two distinct morphologies was used as the catalyst, since the redox reaction of CeO2 with water and organics is expected and its activity can be controlled by its structure. The two roles of water were considered as well.
Water is attractive as a high potential medium with low dielectric constant and density at near the critical point, enabling formation of highly crystalline smaller metal oxides particles. However, the chemical effects of water were studied with heavy oil catalytic cracking. Transmission electron microscopy images indicated that CeO2 nanoparticles with cubic and octahedral shape were synthesized using a plug-flow reactor under hydrothermal conditions.
The particles sizes were 8 and 50 nm for cubic and octahedral CeO2, respectively. Researchers noted that at 773 K the oxygen storage capacity (OSC) of the cerium oxide nanoparticles with cubic {100} facets was nearly 3.4 times higher than that of the cerium oxide nanoparticles with octahedral {111} facets. Heavy oil fractions of bitumen were cracked in a batch-type reactor at 723 K in order to produce as much light oil as possible. The effect of the catalyst loading and reaction conditions on the conversion rate and coke formation were investigated.
Full Text Source (Subscription or Fee): http://pubs.acs.org/doi/abs/10.1021/ef400855k

Effective Dehydration of Canadian Heavy Crude Oil and DilBit

2013 SPE Heavy Oil Conference - Canada, Jun 11 - 13, 2013 2013, Calgary, Alberta, Canada
Effective Dehydration of Canadian Heavy Crude Oil and DilBit
Erik Sellman, SPE, Terry Murtagh and Benjamin Manuel, Cameron Process and Compression Systems
Abstract
Heavy crude oils and diluted Bitumen ( DilBit ) pose a dehydration challenge. The challenge include reduced crude oil / formation water density difference, higher crude oil viscosity, as well as smaller water droplets due the production techniques used for heavy crude oil production. Higher crude oil conductivity and increased crude oil emulsion viscosity formed by higher water cuts and increased solids content in the crude oil pose further difficulties. Conventional crude oil dehydration vessels use heat, retention time and AC type electrostatic dehydration technology. The AC technology produces limited voltage gradients and is not efficient for treating conductive crude oils. This results in the need for very large vessels and power units. The typical remedy to the above challenges often leads to high operating temperatures, high dosage of demulsifier chemicals, equipment fouling, production upsets and use of very large treaters. This leads to both higher operating expenditure ( OPEX ) and higher capital expenditure ( CAPEX ).
Combined AC / DC electrostatic technologies provide high bulk water removal efficiency in the weaker AC field combined with higher removal efficiency of small water droplets in the stronger DC field. Additional advantages include amplitude modulated electrostatic fields, high frequency AC fields, improved electrode configurations, and improved fluid distribution inside the electrostatic treaters. More efficient dehydration and desalting processes provide potential for operating the treaters and desalters at lower operating temperatures and reduced dosage of demulsifier chemicals.  They also make it possible to use smaller treaters. Authors describe improved crude oil dehydration using advanced electrostatic dehydration technologies and an efficient test method for optimized use of production chemicals. Case studies are presented to illustrate this approach.
Full Text Source (Subscription or Fee): http://www.onepetro.org/mslib/servlet/onepetropreview?id=SPE-165464-MS

Optimizing Feed Mixer Performance In A Paraffinic Froth Treatment Process (Exxonmobil Upstream Research Company)

CATEGORY: BITUMEN
PATENT
Optimizing Feed Mixer Performance In A Paraffinic Froth Treatment Process (Exxonmobil Upstream Research Company)
Publication number
US20120279824 A1
Application number
13/554,792
Publication date
Nov 8, 2012
Inventors
Michael F. Raterman
Arun K. Sharma
Original Assignee
Exxonmobil Upstream Research Company
US 20120279824 A1
Abstract
The invention relates to improved bitumen recovery processes and systems. One process provides for operation of a bitumen froth treatment plant at optimum shear rates in the feed pipe carrying the bitumen froth to the froth settling unit. Another process provides for optimizing the design of a bitumen froth treatment plant by optimizing the diameter of the feed pipe to impart an optimum shear rate to the bitumen froth mixture and further optimizing the volume of the feed pipe to impart an optimum residence time for the bitumen froth stream in the feed pipe. An optimal plant design is also disclosed, the plant including optimal diameter and volume of the feed pipe.
FIELD OF THE INVENTION
The present invention relates generally to producing hydrocarbons. More specifically, the invention relates to methods and systems for optimizing the performance of feed mixing devices in a solvent based froth treatment process.
BACKGROUND OF THE INVENTION
The economic recovery and utilization of heavy hydrocarbons, including bitumen, is one of the world's toughest energy challenges. The demand for heavy crudes such as those extracted from oil sands has increased significantly in order to replace the dwindling reserves of conventional crude. These heavy hydrocarbons, however, are typically located in geographical regions far removed from existing refineries. Consequently, the heavy hydrocarbons are often transported via pipelines to the refineries. In order to transport the heavy crudes in pipelines they must meet pipeline quality specifications.
The extraction of bitumen from mined oil sands involves the liberation and separation of bitumen from the associated sands in a form that is suitable for further processing to produce a marketable product. Among several processes for bitumen extraction, the Clark Hot Water Extraction (CHWE) process represents an exemplary well-developed commercial recovery technique. In the CHWE process, mined oil sands are mixed with hot water to create slurry suitable for extraction as bitumen froth.
The addition of paraffinic solvent to bitumen froth and the resulting benefits are described in Canadian Patents Nos. 2,149,737 and 2,217,300. According to Canadian Patent No. 2,149,737, the contaminant settling rate and extent of removal of contaminants present in the bitumen froth generally increases as (i) the carbon number or molecular weight of the paraffinic solvent decreases, (ii) the solvent to froth ratio increases, and (iii) the amount of aromatic and napthene impurities in the paraffinic solvent decreases. Further, a temperature above about 30 degrees Celsius (° C.) during settling is preferred.
One reason for processing the heavy hydrocarbon product in such a process is to eliminate enough of the solids to meet pipeline transport specifications and the specifications of the refining equipment. For example, the sediment specification of the bitumen product as measured by the filterable solids test (ASTM-D4807) may be used to determine if the product is acceptable. As such, a higher settling rate of solid particles including mineral solids and asphaltenes from the froth-treated bitumen is desirable.
One of the first steps in a bitumen froth treatment process is to introduce the bitumen froth to a settling tank, where a portion of the asphaltenes and mineral solids settle out of the froth. Stirred tanks and static mixers have been used in such settling tanks These are very low shear devices. They were used because it was thought that high shear in settling tanks was detrimental to settling and that low shear only impacted quantity of material precipitated, not the precipitation rate.
Methods to improve the settling rate of the minerals can significantly impact the efficiency of heavy hydrocarbon (e.g. bitumen) recovery processes. There exists a need in the art for a low cost method to produce bitumen which meets various sediment specifications.
SUMMARY OF THE INVENTION
In one aspect of the invention, a method of recovering hydrocarbons is provided. The method includes providing a bitumen froth emulsion containing solids, a feed pipe, and a settling unit; determining an optimum average shear rate for the bitumen froth emulsion; and imparting the optimum shear rate to the bitumen froth emulsion in the feed pipe before the bitumen froth emulsion enters the settling unit. The step of determining the optimum average shear may include measuring a solids concentration of the bitumen froth emulsion in the settling unit at a first average shear rate; adjusting the first average shear rate to an adjusted average shear rate; and repeating the measuring and adjusting steps until the solids concentration is at least below a design target for the bitumen froth emulsion.
In another aspect of the invention, a method of optimizing a bitumen treatment process is provided. The method includes determining an optimum average shear rate for a bitumen froth emulsion provided to a settling unit through a feed pipe; determining an optimum residence time in the feed pipe for the bitumen froth emulsion; calculating an optimum diameter of the feed pipe to impart the optimum shear rate to the bitumen froth emulsion; and calculating an optimum volume of the feed pipe to impart the optimum residence time to the bitumen froth emulsion. The step of determining an optimum shear rate may include measuring a solids concentration of the bitumen froth emulsion in the settling unit at a first average shear rate; adjusting the first average shear rate to an adjusted average shear rate; and repeating the measuring and adjusting steps until the solids concentration is at least below a design target for the bitumen froth emulsion.
In another aspect of the invention, a system for recovering hydrocarbons is provided. The system includes a bitumen stream having solids; a solvent stream; a mixing unit configured to mix the bitumen stream and the solvent stream to form a bitumen froth stream; and a feed pipe to receive the bitumen froth stream and provide the bitumen froth stream to a settling unit through a feed pipe inlet, the feed pipe having a diameter and a volume, wherein the diameter of the feed pipe is configured to induce an optimized shear rate to the bitumen froth stream to promote precipitation of solids.
Free Full Text Source: http://www.google.com/patents/US20120279824?dq=inassignee:exxonmobil&hl=en&sa=X&ei=OrGTUcqSBJet4AOEioGQBg&ved=0CFQQ6AEwBA

Study of bitumen liberation from oil sands ores by on-line visualization

Energy Fuels, Just Accepted Manuscript, Publication Date (Web): April 13, 2012
Study of bitumen liberation from oil sands ores by on-line visualization
Sundeep Srinivasa, Chris Flury, Artin Afacan, Jacob Masliyah, and Zhenghe Xu
Abstract
Describes design of a novel visualization cell to study the kinetics of bitumen liberation from oil sands. The cell allows direct observation of bitumen recession from sand grains in real time under various experimental conditions
This enables a better understanding of bitumen liberation and the critical role of process conditions in bitumen extraction from oil sands ores. Although direct recession of bitumen from sand grains is found to be the primary mechanism of bitumen liberation, the presence of entrained air in oil sand ores greatly enhances bitumen liberation via bitumen spreading over air bubbles. Imaging analysis of the recorded real-time bitumen liberation process allowed quantitative analysis of bitumen liberation kinetics.
Full Text Source (Subscription or Fee): http://pubs.acs.org/doi/abs/10.1021/ef300170m