U.S. patent application number 14/103533 was filed with the patent office on 2014-06-19 for system and process for recovering bitumen from oil sands.
This patent application is currently assigned to Shell Oil Company. The applicant listed for this patent is Shell Oil Company. Invention is credited to John Justin FREEMAN, Stanley Nemec MILAM, Erik Willem TEGELAAR.
Application Number | 20140166543 14/103533 |
Document ID | / |
Family ID | 49883277 |
Filed Date | 2014-06-19 |
United States Patent
Application |
20140166543 |
Kind Code |
A1 |
MILAM; Stanley Nemec ; et
al. |
June 19, 2014 |
SYSTEM AND PROCESS FOR RECOVERING BITUMEN FROM OIL SANDS
Abstract
A system and a process for recovering bitumen from oil sands are
provided. The system includes a bitumen solvent comprised of at
least 75 mol % dimethyl sulfide that is first contact miscible with
bitumen, an oil sands material comprised of bitumen, and a
contacting apparatus configured to receive the bitumen solvent and
the oil sands material and to contact and mix the bitumen solvent
and oil sands material to form a bitumen-containing extract and a
bitumen-depleted oil sands material. The process includes the steps
of providing the oil sands material; contacting the oil sands
material with the solvent comprised of at least 75 mol % dimethyl
sulfide to form the bitumen-containing extract and the
bitumen-depleted oil sands material; and separating the
bitumen-containing extract from the bitumen-depleted oil sands
material.
Inventors: |
MILAM; Stanley Nemec;
(Houston, TX) ; TEGELAAR; Erik Willem; (Rijswijk,
NL) ; FREEMAN; John Justin; (Pattison, TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Shell Oil Company |
Houston |
TX |
US |
|
|
Assignee: |
Shell Oil Company
Houston
TX
|
Family ID: |
49883277 |
Appl. No.: |
14/103533 |
Filed: |
December 11, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61736889 |
Dec 13, 2012 |
|
|
|
Current U.S.
Class: |
208/390 ;
196/14.52 |
Current CPC
Class: |
C10G 1/045 20130101;
C10G 1/04 20130101 |
Class at
Publication: |
208/390 ;
196/14.52 |
International
Class: |
C10G 1/04 20060101
C10G001/04 |
Claims
1. A process for separating bitumen from oil sands, comprising:
providing an oil sands material comprising bitumen and inorganic
solid particulate matter; contacting the oil sands material with a
solvent comprising at least 75 mol % dimethyl sulfide to form an
extract comprising the solvent and bitumen extracted from the oil
sands material and to form a bitumen-depleted oil sands material;
separating the extract from the bitumen-depleted oil sands
material.
2. The process of claim 1 wherein the solvent is first contact
miscible with bitumen.
3. The process of claim 1 wherein the extract separated from the
bitumen-depleted oil sands material comprises at most 500 parts per
million by weight of inorganic solid particulate matter.
4. The process of claim 1 wherein the contacting and separating are
conducted in the absence of any water other than water contained in
the oil sands material.
5. The process of claim 1 wherein solvent is contacted with the oil
sands material in a weight ratio of solvent to oil sands material
of at least 1:1.
6. The process of claim 1 wherein the solvent has a density of at
most 0.9 g/cm.sup.3 at 25.degree. C. and 0.101 MPa.
7. The process of claim 1 wherein the solvent has a dynamic
viscosity at 20.degree. C. of at most 0.3 mPa s (cP).
8. The process of claim 7 wherein the step of providing an oil
sands material comprises providing an oil sands material comprised
of bitumen having a viscosity at 20.degree. C. of at least 5000 mPa
s; and wherein the step of contacting the oil sands material and
the solvent forms an extract having a dynamic viscosity at
20.degree. C. of at most 500 mPa s.
9. The process of claim 1 wherein the solvent has a boiling point
of at most 45.degree. C. at 0.101 MPa.
10. The process of claim 1 further comprising the step of
separating residual solvent from the separated bitumen-depleted oil
sands material and recovering the residual solvent therefrom.
11. The process of claim 10 wherein the step of contacting the oil
sands material with a solvent comprises contacting the oil sands
material with residual solvent recovered from the bitumen-depleted
oil sands material.
12. The process of claim 1 wherein the solvent is comprised of at
least 90 mol % dimethyl sulfide.
13. The process of claim 1 further comprising the step of
separating at least a portion of the solvent from the extract to
produce bitumen.
14. The process of claim 13 further comprising the steps of: prior
to separating at least a portion of the solvent from the extract,
transporting the extract to an oil processing facility; and
subsequent to separating at least a portion of the solvent from the
extract, contacting the separated portion of the solvent with an
oil sands material to form a bitumen-containing extract and a
bitumen-depleted oil sands material.
15. The process of claim 13 further comprising the step of refining
the bitumen from which at least a portion of the solvent has been
removed.
16. The process of claim 1 wherein the oil sands material is
provided by mining the oil sands material.
17. The process of claim 16 further comprising the step of
crushing, milling, or pulverizing the mined oil sands material
prior to contacting the oil sands material with the solvent.
18. The process of claim 1 wherein the oil sands material has a
tensile strength of 0 Pa.
19. A system comprising: a bitumen solvent that is first contact
miscible with bitumen, the solvent comprising at least 75 mol %
dimethyl sulfide; an oil sands material comprising bitumen and
inorganic solid particulate matter; a contacting apparatus
configured to receive the bitumen solvent and the oil sands
material and to contact and mix the bitumen solvent and the oil
sands material to form a bitumen-containing extract and a
bitumen-depleted oil sands material.
20. The system of claim 19, further comprising a clarifier
operatively coupled to the contacting apparatus to receive the
bitumen-containing extract and the bitumen-depleted oil sands
material from the contacting vessel and configured to separate the
bitumen-containing extract from the bitumen-depleted oil sands
material.
21. The system of claim 19 wherein the contacting apparatus is
further configured to separate the bitumen-containing extract from
the bitumen-depleted oil sands material.
22. The system of claim 21 further comprising a fines separator
configured to separate solid particles having a particle diameter
of less than 44 .mu.m from the bitumen-containing extract.
23. The system of claim 19 further comprising a solvent recovery
apparatus operatively coupled to the contacting apparatus to
receive the bitumen-depleted oil sands material, wherein the
bitumen-depleted oil sands material comprises a portion of the
bitumen solvent, and wherein the solvent recovery apparatus is
configured to separate at least portion of the bitumen solvent from
the bitumen-depleted oil sands material.
24. The system of claim 23 wherein the solvent recovery apparatus
is operatively fluidly coupled to the contacting apparatus to
provide the portion of the bitumen solvent separated from the
bitumen-depleted oil sands material to the contacting apparatus.
Description
[0001] This present application claims the benefit of U.S. Patent
Application No. 61/736,889, filed Dec. 13, 2012.
FIELD OF THE INVENTION
[0002] The present invention relates to a system and a process for
recovering bitumen from oil sands.
BACKGROUND OF THE INVENTION
[0003] Some of the world's largest deposits of oil are located in
oil sands formations. Oil sands are comprised of a matrix of
loosely consolidated or unconsolidated inorganic solid particulate
materials such as sand and clay permeated with oil and water. The
oil present in a large proportion of oil sands is viscous bitumen
or heavy oil typically having an API gravity of 15 or less.
[0004] Bitumen present in oil sands located within 100 meters of
the earth's surface is typically recovered and produced by surface
mining the oil sands and then extracting the bitumen from the mined
oil sands ore. The oil sands are mined by digging the oil sands
from the earth, then transporting the unearthed oil sands ore to a
bitumen extraction facility. Bitumen is extracted from the oil
sands ore in the extraction facility by crushing the oil sands ore
into particulates, mixing the crushed oil sands with an extractant,
capturing the bitumen in the extractant, and separating the
resulting bitumen-containing extract from the inorganic solid
particulates of the oil sand.
[0005] The most common method of extracting bitumen from mined oil
sands ore involves separating the bitumen from inorganic solid
particulate material in the oil sands using hot water containing an
alkali as the extractant. Hot water, caustic soda, and the mined
oil sands ore are mixed into a slurry, and the bitumen is allowed
to float to the surface of the slurry where it forms a froth. The
bitumen froth is then separated from the inorganic solid
particulate material. Clean oil is produced from the separated
bitumen froth by treating the froth to remove water and mineral
fines. Water is separated and recovered from the spent inorganic
solid particulate material from which the bitumen froth is
separated, and is recycled for reuse as an extractant.
[0006] Water management, however, has become a significant problem
resulting from the use of water as an oil sands extractant. Water
separated from the bulk of the spent inorganic solid particulate
oil sand materials contains substantial quantities of mineral fines
that are not separated from the water with the bulk of the
inorganic particulates. These fines are suspended in the water, and
are not easily separated from the water by conventional mechanical
solid/liquid separation techniques such as filtration and
centrifugation. Therefore, the mineral fines are separated from the
water by placing the water containing the mineral fines in tailings
ponds to allow the mineral fines to settle out from the water. Such
tailings ponds are undesirable, and have become a significant
environmental issue.
[0007] Other oil sands extraction processes have been developed
utilizing an organic solvent containing one or more organic
compounds as an extractant. The solvent and oil sands extraction
conditions, e.g. temperature and pressure, may be selected to
dissolve and extract non-asphaltenic hydrocarbons from the oil
sands either with or without a portion of asphaltenic hydrocarbons.
One solvent extraction process provides for extracting crushed oil
sands ore with heptanes, separating coarse sand from the solvent
and extracted bitumen by hydrocyclones, centrifuges, and/or belt
filters, then separating mineral fines from the solvent/bitumen
mixture by adding pentane to the extraction mixture to induce
pentane deasphalting in which C.sub.5 insoluble asphaltenes are
flocculated from the heptane/bitumen extraction mixture to capture
the fines and separating the flocculated asphaltenes containing the
captured fines from the extraction mixture. (See, A Solvent
Extraction Process for Tar Sand, R. Graham, J. Helstrom, and R.
Mehlberg, 1987 Eastern Oil Shale Symposium, Commonwealth of
Kentucky, Kentucky Energy Cabinet, pp. 93-99 (1987)). The
non-asphaltenic hydrocarbons may then be recovered from the
extraction mixture. The recovered hydrocarbons account for
approximately 73 wt. % of the bitumen.
[0008] WO2011/021092 describes a process of separating bitumen from
an oil sands material by contacting the oil sands material with at
least one aliphatic hydrocarbon solvent selected from pentane,
hexanes, heptanes, and any mixture thereof to form a mass,
agglomerating at least a portion of fines and coarse inorganic
material, and separating the agglomerated inorganic material and
coarse inorganic material to leave a slurry of organic material and
non-agglomerated fines. The aliphatic solvent is selected to
dissolve non-asphaltenic bitumen material while inhibiting the
complete dissolution of asphaltenic material into the solvent,
where the non-dissolved asphaltenic material may be used to help
agglomerate the fines. After removal of the coarse inorganic
material and the agglomerated asphaltenes and fines, the organic
material in the slurry may be separated from the non-agglomerated
fines by 1) dissolving asphaltenes in the slurry using heat and
pressure to reduce the viscosity of the solution, separating the
non-agglomerated fines (e.g. by centrifugation) from the reduced
viscosity solution, subsequently re-dispersing the insoluble
asphaltenes in the slurry, and then separating a bitumen liquor
from dispersed, non-dissolved asphaltenes; or 2) separating the
non-dissolved asphaltenes and fines associated therewith from the
slurry to form a bitumen liquor, where the separated asphaltenes
may be separated from the separated fines by heating and separation
of the fines from the asphaltenes (e.g. by centrifuge). The
products of the process are a bitumen liquor from which asphaltenes
and inorganic materials have been removed and asphaltenes as
separate product streams.
[0009] US Patent Application Publication No. 2010/0130386 describes
a process of extracting bitumen from oil sands with a solvent that
increases the rate of recovery of bitumen from the oil sands
relative to conventional hydrocarbon solvents such as pentane using
a solvent formed of a combination of components, where the solvent
has a Hansen hydrogen bonding parameter of 0.3 to 1.7. The
combination of components includes a polar component that comprises
a compound comprising a non-terminal carbonyl group and a non-polar
component that comprises a compound that is a substantially
aliphatic substantially non-halogenated alkane. The polar component
of the solvent increases the rate of penetration of the solvent
into the oil sands, while the non-polar component dissolves
non-asphaltenic hydrocarbons in the oil sands. The polar solvent
also likely dissolves a portion of the asphaltenic hydrocarbons in
the oil sands, so the overall hydrocarbon recovery from the oil
sands is increased relative to non-polar aliphatic hydrocarbon
solvents (approximately 86 wt. % bitumen recovery).
[0010] These solvent extraction processes sacrifice hydrocarbon
yield to avoid difficulties in separating the extracted bitumen
from inorganic material fines. Asphaltenes are at least partially
excluded from solvent extraction processes because 1) the preferred
solvents, particularly non-polar aliphatic hydrocarbon solvents
such as pentane, hexanes, and heptanes, are not effective to
solvate all asphaltenes; and 2) asphaltenes may be flocculated to
capture inorganic material fines so that the asphaltenes and fines
may be removed from the extracted bitumen together. Loss of
asphaltenes is considered acceptable in some processes since
asphaltenes require cracking and hydrotreatment to provide more
valuable lower molecular weight hydrocarbons.
[0011] The loss of asphaltenic hydrocarbons, however, is a
significant hydrocarbon yield loss. In refining processes, at least
50% of asphaltenes can be converted to high value lower molecular
weight hydrocarbons. In a solvent extraction process recovering
only 73 wt. % of bitumen from an oil sands ore, such as processes
excluding asphaltenes from the recovery by flocculation of the
asphaltenes with a C.sub.5, C.sub.6, or C.sub.7 solvent, up to 15
wt. % of recoverable hydrocarbons that can be converted to high
value low molecular weight hydrocarbons may be excluded from
recovery.
[0012] Aromatic solvents such as toluene and o-xylene are known to
be highly effective as solvents for extracting all hydrocarbon
components from oil sands ores. Use of such aromatic solvents in an
oil sands solvent extraction process, however, is impractical due
to the expense of the solvents and the inefficiency of solvent
separation and recovery from the spent oil sands material due to
the relatively high boiling point of such solvents.
[0013] It is desirable to provide an oil sands solvent extraction
process and system effective to provide improved hydrocarbon
recovery in which inorganic solid particulate materials, including
mineral fines, may be easily removed from a bitumen solvent extract
in the absence of tailings ponds, and in which solvent separation
and recovery from spent oil sands material is improved relative to
aromatic solvents.
SUMMARY OF THE INVENTION
[0014] In one aspect, the present invention is directed to a
process for separating bitumen from oil sands comprising: providing
an oil sands material comprising bitumen and inorganic solid
particulate matter; contacting the oil sands material with a
solvent comprising at least 75 wt. % dimethyl sulfide or 75 mol %
dimethyl sulfide to form an extract comprising the solvent and
bitumen extracted from the oil sands and to form a bitumen-depleted
oil sands material; and separating the extract from the
bitumen-depleted oil sands material.
[0015] In another aspect, the present invention is directed to a
system comprising a bitumen solvent that is first contact miscible
with bitumen, the solvent comprising at least 75 wt. % or 75 mol %
dimethyl sulfide; an oil sands material comprising bitumen and
inorganic solid particulate matter; and a contacting apparatus
configured to receive the bitumen solvent and the oil sands
material and to contact the bitumen solvent and the oil sands
material to form a bitumen-containing extract and a
bitumen-depleted oil sands material.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1 illustrates a system in accordance with the present
invention that may be utilized to effect a process in accordance
with the present invention.
[0017] FIG. 2 illustrates another system in accordance with the
present invention that may be utilized to effect a process in
accordance with the present invention.
[0018] FIG. 3 illustrates a further system in accordance with the
present invention that may be utilized to effect a process in
accordance with the present invention.
[0019] FIG. 4 is a graph showing petroleum recovery from oil sands
at 30.degree. C. using various solvents.
[0020] FIG. 5 is a graph showing petroleum recovery from oil sands
at 10.degree. C. using various solvents.
[0021] FIG. 6 is a graph showing the viscosity reducing effect of
increasing concentrations of dimethyl sulfide on a West African
Waxy crude oil.
[0022] FIG. 7 is a graph showing the viscosity reducing effect of
increasing concentrations of dimethyl sulfide on a Middle Eastern
Asphaltic crude oil.
[0023] FIG. 8 is a graph showing the viscosity reducing effect of
increasing concentrations of dimethyl sulfide on a Canadian
Asaphaltic crude oil.
DETAILED DESCRIPTION OF THE INVENTION
[0024] The present invention is directed to a system and a process
for separating bitumen from a bitumen-containing oil sands
material. The system and the process utilize a solvent comprising
at least 75 wt. % dimethyl sulfide or 75 mol % (hereafter the
"bitumen solvent") to extract bitumen from a bitumen-containing oil
sands material. Unlike most organic solvents used to extract
bitumen from oil sands, the bitumen solvent is effective to solvate
substantially all hydrocarbons from the oil sands material
including substantially all asphaltenes, aromatics, resins, and
saturates, including paraffins. As a result, the process of the
present invention is effective to increase hydrocarbon recovery
yield from oil sands relative to conventional oil sands solvent
extractions. Furthermore, the bitumen solvent of the system and
process of the present invention may have a very low dynamic
viscosity, for example less than 0.3 mPa s (cP) at 25.degree. C.,
that enables the removal of inorganic solid particulate fines from
a mixture of the bitumen solvent and bitumen by mechanical
separation or a rapid settling separation, eliminating the need for
a tailings pond to separate the fines. The bitumen solvent of the
system and process of the present invention may also have a low
boiling point, for example at most 45.degree. C. at 0.101 MPa,
enabling separation and recovery of the solvent from
bitumen-depleted oil sands with less energy than higher boiling
bitumen extraction solvents. The bitumen solvent of the system and
process of the present invention also has very low toxicity,
rendering use of the solvent in a large scale commercial system and
process attractive.
[0025] Referring now to FIGS. 1, 2, and 3, systems 100, 200, and
300 in accordance with the present invention are shown that may be
utilized for conducting a process in accordance with the present
invention. The systems 200 and 300 depicted in FIGS. 2 and 3,
respectively, may be similar in some respects to the system 100
depicted in FIG. 1. Accordingly, certain components of the systems
200 and 300 may be understood with reference to the component
numerals in FIG. 1, where like numerals are used to indicate like
components.
[0026] Referring to FIGS. 1, 2, and 3, a bitumen solvent 101 and a
bitumen-containing oil sands material 105 are provided to a
contacting apparatus 103 that is configured to receive and mix the
bitumen solvent and the oil sands material to form an extract
containing substantially all of the bitumen and a bitumen-depleted
oil sands material.
[0027] The bitumen solvent 101 provided for use in the method or
system of the present invention is comprised of at least 75 wt. %
or 75 mol % dimethyl sulfide. The bitumen solvent may be comprised
of at least 80 wt. %, or at least 85 wt. %, or at least 90 wt. %,
or at least 95 wt. %, or at least 97 wt. %, or at least 99 wt. %
dimethyl sulfide. The bitumen solvent may be comprised of at least
80 mol %, or at least 85 mol %, or at least 90 mol %, or at least
95 mol %, or at least 97 mol %, or at least 99 mol % dimethyl
sulfide. The bitumen solvent may consist essentially of dimethyl
sulfide, or may consist of dimethyl sulfide.
[0028] The bitumen solvent 101 provided for use in the method or
system of the present invention may be comprised of one or more
co-solvents that form a mixture with the dimethyl sulfide in the
bitumen solvent. The one or more co-solvents are preferably
miscible with dimethyl sulfide. The one or more co-solvents may be
selected from the group consisting of o-xylene, toluene, carbon
disulfide, dichloromethane, trichloromethane, C.sub.3-C.sub.8
aliphatic and aromatic hydrocarbons, natural gas condensates,
hydrogen sulfide, diesel, kerosene, dimethyl ether, and mixtures
thereof. In an embodiment of the system and process of the present
invention, water is absent from the bitumen solvent and the bitumen
solvent is free of water.
[0029] The bitumen solvent may be primarily in liquid phase, where
at least 75 wt. %, or at least 90 wt. %, or at least 95 wt. % or at
least 75 mol %, or at least 90 mol %, or at least 95 mol % of the
bitumen solvent may be in liquid phase. Preferably, substantially
all of the bitumen solvent is in liquid phase.
[0030] The bitumen solvent 101 provided for use in the method or
system of the present invention is first contact miscible with
bitumen, heavy oils, and liquid phase petroleum compositions,
preferably any liquid phase petroleum composition. The bitumen
solvent may be first contact miscible with crude oils having an API
gravity of 15 or less, including bitumen. The bitumen solvent may
be first contact miscible with a hydrocarbon composition, for
example a liquid phase crude oil, that comprises at least 25 wt. %,
or at least 30 wt. %, or at least 35 wt. %, or at least 40 wt. %
hydrocarbons that have a boiling point of at least 538.degree. C.
(1000.degree. F.) as determined by ASTM Method D5307. The bitumen
solvent may be first contact miscible with liquid phase residue and
liquid phase asphaltenes in a hydrocarbonaceous composition, for
example, in bitumen. The bitumen solvent may be first contact
miscible with a hydrocarbon composition that comprises less than 25
wt. %, or less than 20 wt. %, or less than 15 wt. %, or less than
10 wt. %, or less than 5 wt. % of hydrocarbons having a boiling
point of at least 538.degree. C. (1000.degree. F.) as determined by
ASTM Method D5307. The bitumen solvent may be first contact
miscible with C.sub.3 to C.sub.8 aliphatic and aromatic
hydrocarbons containing less than 5 wt. % oxygen, less than 10 wt.
% sulfur, and less than 5 wt. % nitrogen.
[0031] The bitumen solvent 101 may be first contact miscible with
hydrocarbon compositions, for example a crude oil or liquid phase
petroleum, over a wide range of viscosities. The bitumen solvent
may be first contact miscible with a hydrocarbon composition having
a low or moderately low viscosity. The bitumen solvent may be first
contact miscible with a hydrocarbon composition, for example a
liquid phase petroleum, having a dynamic viscosity of at most 1000
mPa s (1000 cP), or at most 500 mPa s (500 cP), or at most 100 mPa
s (100 cP) at 25.degree. C. The bitumen solvent may also be first
contact miscible with a hydrocarbon composition having a moderately
high or a high viscosity. The bitumen solvent may be first contact
miscible with a hydrocarbon composition, for example a liquid phase
petroleum, having a dynamic viscosity of at least 1000 mPa s (1000
cP), or at least 5000 mPa s (5000 cP), or at least 10000 mPa s
(10000 cP), or at least 50000 mPa s (50000 cP), or at least 100000
mPa s (100000 cP), or at least 500000 mPa s (500000 cP) at
25.degree. C. The bitumen solvent may be first contact miscible
with hydrocarbon composition, for example a liquid phase petroleum,
having a dynamic viscosity of from 1 mPa s (1 cP) to 5000000 mPa s
(5000000 cP), or from 100 mPa s (100 cP) to 1000000 mPa s (1000000
cP), or from 500 mPa s (500 cP) to 500000 mPa s (500000 cP), or
from 1000 mPa s (1000 cP) to 100000 mPa s (100000 cP) at 25.degree.
C.
[0032] The bitumen solvent provided for use in the method or system
of the present invention may have a low viscosity. The bitumen
solvent may be a fluid having a dynamic viscosity of at most 0.35
mPa s (0.35 cP), or at most 0.3 mPa s (0.3 cP), or at most 0.285
mPa s (0.285 cP) at a temperature of 25.degree. C. The low
viscosity of the bitumen solvent may enable removal of inorganic
solid material fines from a mixture of the solvent and bitumen by
mechanical separation or by settling in a relatively short period
of time.
[0033] The bitumen solvent 101 provided for use in the method or
system of the present invention preferably has a relatively low
density. The bitumen solvent may have a density of at most 0.9
g/cm.sup.3, or at most 0.85 g/cm.sup.3.
[0034] The bitumen solvent 101 provided for use in the method or
system of the present invention may have a relatively high cohesive
energy density. The bitumen solvent provided for use in the method
or system of the present invention may have a cohesive energy
density of from 300 MPa to 410 MPa, or from 320 MPa to 400 MPa.
[0035] The bitumen solvent 101 provided for use in the method or
system of the present invention preferably is relatively non-toxic
or is non-toxic. The bitumen solvent may have an aquatic toxicity
of LC.sub.50 (rainbow trout) greater than 200 mg/l at 96 hours. The
bitumen solvent may have an acute oral toxicity of LD.sub.50 (mouse
and rat) of from 535 mg/kg to 3700 mg/kg, an acute dermal toxicity
of LD.sub.50 (rabbit) of greater 5000 mg/kg, and an acute
inhalation toxicity of LC.sub.50 (rat) of at least 40250 ppm at 4
hours.
[0036] The oil sands material 105 provided for use in the process
or system of the present invention is comprised of bitumen and
grains of inorganic solid particulate material. The oil sands
material may be comprised of 1 wt. % to 25 wt. % of bitumen.
"Bitumen" as used herein may refer to a heavy oil or an extra heavy
oil having an API Gravity of at most 15 as determined by ASTM
Method D287. The inorganic solid particulate material of the oil
sands material may be comprised of inorganic minerals selected from
the group consisting of sand, silt, fines, clay, and mixtures
thereof. The oil sands material may also comprise water. The oil
sands material may be water-wet, where at least a majority of the
inorganic solid particulate material of the oil sands material is
coated with a layer of water with the bitumen being located in the
void space around the wetted inorganic solid particulate material
grains. Alternatively, the oil sands material may be oil-wet, where
at least a majority of the inorganic solid particulate material of
oil sands material is coated with bitumen. In some embodiments, the
bitumen may comprise between about 1 wt. % and about 16 wt. % of
the oil sands material; sand and clay may comprise between about 80
wt. % and about 85 wt. % of the oil sands material; and the water
may comprise between about 1 wt. % and about 16 wt. % of the oil
sands material.
[0037] The oil sands material 105 may be formed of unconsolidated
or loosely consolidated inorganic material particles so that the
oil sands material may be easily extracted with the bitumen
solvent. Unconsolidated oil sands material may have a tensile
strength of 0 Pa. The inorganic solid particles may have an average
diameter of from 10 .mu.m to 5 mm, where particles having an
average diameter of from 10 .mu.m to 43.99 .mu.m are fines and
particles having an average diameter of from 44 .mu.m to 5 mm are
medium and coarse inorganic particles.
[0038] The oil sands material 105 may be provided by mining the oil
sands material from a formation containing oil sands. A formation
containing oil sands from which the oil sands material may be mined
may be located from the surface of the earth to 100 meters below
the surface of the earth, or to 60 meters below the surface of the
earth. The formation containing oil sands may be an oil sands
formation, an oil shale formation, an oil-bearing diatomite
formation, or a tar-saturated sandstone formation. The formation
containing oil sands may comprise the oil sands material located
beneath an overburden. The oil sands material may be mined from a
formation containing oil sands by digging the oil sands material
out of the formation and collecting the oil sands material
recovered from the formation.
[0039] Mined oil sands material containing substantial quantities
of consolidated solid material having a particle size greater than
5 mm may be crushed, milled, or pulverized to break consolidated
portions of the oil sands material into unconsolidated solid
particulates prior to being provided to the contacting apparatus
103 for contact and mixing with the bitumen solvent 101 to enhance
the ease of extraction of bitumen from the oil sands material.
Preferably, the mined oil sands material is crushed, milled, or
pulverized sufficiently to render the oil sands material into
unconsolidated solid particulates without forming excessive
quantities of inorganic material fines. The mined oil sands
material may be crushed, milled, or pulverized to provide an oil
sands material having an average particle diameter of from 10.mu.m
to 5 mm, where at most 15 wt. % of the crushed, milled, or
pulverized oil sands material may have an average particle diameter
of less than 44 .mu.m.
[0040] The contacting apparatus 103 is configured to receive the
bitumen solvent 101 and the oil sands material 105 and to contact
and mix the solvent and oil sands material to form a
bitumen-containing extract 107 and a bitumen-depleted oil sands
material 109. Referring now to FIG. 1, the contacting apparatus may
be a slanted pipe or trough 110 having a solids transport screw 111
extending therethrough. The bitumen solvent 101 and the oil sands
material 105 may be introduced into an upper portion of the pipe or
trough 110 and move downward through the pipe or trough
co-currently, where the oil sands material may be carried down the
pipe or trough 110 on the flights of the solids transport screw 111
by rotating the screw. The solids transport screw 111 may be
positioned in the pipe or trough 110 with the screw flights
extending to within 5 centimeters, or to within 1 centimeter, of
the inner surface of the pipe or trough to inhibit the oil sands
material from passing straight through the pipe or trough outside
the diameter of the screw. The screw flights may be pitched to
maximize contact of the oil sands material with the bitumen solvent
as the oil sands material and solvent proceed through the
contacting apparatus. The screw flights may also have corrugations
therein to promote the lifting of the oil sands material by the
screw to ensure thorough mixing of the oil sands material with the
bitumen solvent.
[0041] Alternatively, referring now to FIG. 2, the contacting
apparatus 103 may be a slanted pipe or trough 210 having a solids
transport screw 211 extending therethrough where the oil sands
material 105 may be introduced into a lower portion of the pipe or
trough 210 and the bitumen solvent 101 may be introduced into an
upper portion of the pipe or trough. The solids transport screw 211
may be positioned in the pipe or trough to carry the oil sands
material 105 upwards through the pipe or trough 210 on the flights
of the screw by rotating the screw. The bitumen solvent 101 may
flow downwards through the pipe or trough 210 and contact the oil
sands material 105 in the pipe or trough in a counter-current flow.
The solids transport screw 211 may be positioned in the pipe or
trough 210 with the screw flights extending to within 5
centimeters, or to within 1 centimeter, of the inner surface of the
pipe or trough to inhibit the oil sands material from falling as it
is carried upward through the pipe by the screw. The screw flights
of the screw 211 may have small perforations therein to permit the
bitumen solvent to pass through the flights after contacting the
oil sands material, where the perforations are configured to
inhibit the oil sands material from falling through the
perforations. The screw flights of the screw 211 may be pitched to
maximize contact of the oil sands material with the solvent as the
oil sands material and solvent proceed through the contacting
apparatus. The screw flights of the screw 211 may also have
corrugations therein to promote the lifting of the oil sands
material by the screw.
[0042] In an alternative embodiment of the contacting apparatus 103
utilized as shown in FIGS. 1 and 2, the pipe 110 or 210 may have
helical flights extending from the interior wall of the pipe
radially inward to the center of the pipe rather than having a
transport screw 111 or 211 extending through the pipe 110 or 210,
respectively. In this embodiment, the oil sands material is carried
through the pipe on the helical flights by rotating the pipe 110 or
210, and the contacting apparatus may have a mechanism for rotating
the pipe having the helical flights. Bitumen solvent 101 may be
contacted with the oil sands material 105 co-currently as shown in
FIG. 1, or counter-currently as shown in FIG. 2, as the oil sands
material is transported through the pipe 110 or 210 on the helical
flights within the pipe.
[0043] Alternatively, referring now to FIG. 3, the contacting
apparatus 103 may be a conventional mixer-settler apparatus having
a mixing tank 310 and an adjoining setting tank 311. The mixing
tank 310 may be configured to receive the oil sands material 105
and the bitumen solvent 101 therein. The oil sands material 105 and
the bitumen solvent 101 may be provided to the mixing tank 310, and
may be contacted and mixed together in the mixing tank. The mixing
tank may have an impeller 313 for stirring and mixing the oil sands
material and the bitumen solvent. After mixing, at least a portion
of the mixed oil sands material 105 and the bitumen solvent 101 may
be provided from the mixing tank 310 to the settling tank 311,
which may be configured to receive the mixture of oil sands
material and the bitumen solvent from the mixing tank. The settling
tank 311 may be configured to enable the liquid bitumen-containing
extract portion of the mixture 107 and the solid bitumen-depleted
oil sands material portion 109 of the mixture to separate, for
example by gravity.
[0044] Referring again to FIGS. 1, 2, and 3, the bitumen solvent
101 may be provided to the contacting apparatus 103 in an amount
effective to solvate a substantial portion, preferably at least 90
wt. %, or at least 95 wt. %, or at least 99 wt. % of the bitumen in
the oil sands material 105 provided to the contacting apparatus
upon contact and mixing with the oil sands material. The bitumen
solvent 101 may be contacted with the oil sands material 105 in a
weight ratio of solvent to oil sands material of at least 1:1, or
at least 2:1, up to 10:1, or up to 5:1, or from 1:1 to 10:1, or
from 2:1 to 5:1. Preferably the bitumen solvent and the oil sand
material are contacted and mixed in the absence of water other than
water present in the oil sands material--the contacting and mixing
may be conducted free of additional water.
[0045] The oil sands material 105 provided for contact with the
bitumen solvent 101 in the contacting apparatus 103 may be
comprised of bitumen having a relatively high dynamic viscosity,
and the bitumen solvent 101 provided for contact with the oil sands
material may have a relatively low dynamic viscosity, such that the
step of contacting the oil sands material and the bitumen solvent
forms a bitumen-containing extract having a relatively low dynamic
viscosity. The oil sands material 105 provided for contact with the
bitumen solvent 101 may be comprised of bitumen having a dynamic
viscosity at 20.degree. C. of at least 5000 mPa s (cP), or at least
50,000 mPa s (cP), or at least 100,000 mPa s (cP), or at least
500,000 mPa s (cP). The bitumen solvent 101 provided for contact
with the oil sands material 105 may have a dynamic viscosity at
20.degree. C. of at most 0.35 mPa s (cP), or at most 0.3 mPa s
(cP), or at most 0.285 mPa s (cP). The bitumen-containing extract
107 formed by contacting and mixing the oil sands material 105 and
the bitumen solvent 101 may have a dynamic viscosity at 20.degree.
C. of at most 500 mPa s (cP), or at most 100 mPa s (cP). The
bitumen-containing extract may be relatively easily separated from
the bitumen-depleted oil sands material due to the relatively low
viscosity of the bitumen-containing extract.
[0046] After contacting and mixing the bitumen solvent 101 and the
oil sands material 105 to form the bitumen-containing extract 107
and the bitumen-depleted oil sands material 109, the
bitumen-containing extract and the bitumen-depleted oil sands
material may be separated. In some embodiments of the system and
the process of the present invention, separation of the
bitumen-containing extract 107 from the bitumen-depleted oil sands
material 109 may be effected by removing the extract and the
bitumen-depleted oil sands material from the contacting apparatus
103. Referring to FIG. 2, the bitumen-containing extract 107 may be
separated from the bitumen-depleted oil sands material 109 as the
extract exits the bottom portion of the pipe or trough 210 of the
contacting apparatus 103 in a counter-current flow relative to the
oil sands material. The bitumen-depleted oil sands material 109 may
be separated from the bitumen-containing extract as the
bitumen-depleted oil sands material exits the top portion of the
pipe or trough 210 of the contacting apparatus 103. Alternatively,
referring to FIG. 3, the bitumen-depleted oil sands material may
settle gravitationally into a bottom portion of the settling tank
311 of the contacting apparatus, and the bitumen-containing extract
107 may be removed from a top portion of the settling tank after
the bitumen-depleted oil sands material has settled into the bottom
portion of the settling tank to separate the bitumen-containing
extract from the bitumen-depleted oil sands material. The
bitumen-depleted oil sands material 109 may be removed from the
bottom portion of the settling tank to separate the
bitumen-depleted oil sands material from the bitumen-containing
extract 107.
[0047] In other embodiments of the system and process of the
present invention, separation of the bitumen-containing extract 107
and the bitumen-depleted oil sands material 109 may be effected
after the extract and the bitumen-depleted oil sands material have
been removed from the contacting apparatus 103. Referring now to
FIG. 1, in some embodiments of the system of the present invention,
the system may comprise a clarifier 113 operatively fluidly
connected to the contacting apparatus 103 to receive a mixture of
the bitumen-containing extract and the bitumen-depleted oil sands
material from the contacting apparatus and configured to separate
the bitumen-containing extract 107 and the bitumen-depleted oil
sands material 109. After the bitumen solvent 101 and the oil sands
material 105 have been contacted and mixed in the contacting
apparatus 103 to produce the bitumen-containing extract and the
bitumen-depleted oil sands material, the extract and the
bitumen-depleted oil sands material may be provided from the
contacting apparatus to the clarifier 113. The bitumen-depleted oil
sands material may gravitationally settle to the bottom portion of
the clarifier, and the bitumen-containing extract 107 may be
separated from the bitumen-depleted oil sands material by removing
the extract from the top portion of the clarifier after settling of
the bitumen-depleted oil sands material. After settling, the
bitumen-depleted oil sands material 109 may be removed from the
bottom portion of the clarifier to separate the bitumen-depleted
oil sands material from the bitumen-containing extract.
[0048] In a preferred embodiment of the process of the present
invention, separation of the bitumen-containing extract and the
bitumen-depleted oil sands material may be effected in the absence
of water other than water contained in the oil sands material--free
of additional water--since the presence of significant quantities
of water in the separation step may inhibit the separation of
inorganic particulate fines from the bitumen-containing
extract.
[0049] Referring again to FIGS. 1, 2, and 3, the separated
bitumen-depleted oil sands material 109 may contain residual
bitumen solvent therein, which may be recovered from the
bitumen-depleted oil sands material. The bitumen-depleted oil sands
material 109 may be provided to a solvent stripper 121 to recover
the residual solvent from the bitumen-depleted oil sands material.
The temperature and the pressure in the solvent stripper may be
controlled to strip the residual solvent from the bitumen-depleted
oil sands material. For example, if the bitumen solvent is formed
of 100 wt. % or 100 mol % dimethyl sulfide, the temperature of the
solvent stripper may be controlled to be 50.degree. C. and the
pressure of the stripper may be controlled to be 0.101 MPa to strip
the dimethyl sulfide residual solvent from the bitumen-depleted oil
sands material. One advantage of the process of the present
invention is that relatively little energy is required to strip the
residual bitumen solvent from the bitumen-depleted oil sands
material relative to other bitumen solvents that are effective to
solvate substantially all of the asphaltenes from an oil sands
material--such as toluene and o-xylene--due to the relatively low
boiling point of the bitumen solvent used in the process of the
present invention.
[0050] The residual bitumen solvent 123 stripped from the
bitumen-depleted oil sands material may be recycled for reuse to
extract bitumen from fresh oil sands material 105 by introducing
the residual bitumen solvent into the contacting apparatus 103. The
stripped bitumen-depleted oil sands material 125 may be returned to
its originating site after mining at the originating site is
complete, thereby reclaiming the originating site.
[0051] The bitumen-containing extract 107 may contain relatively
small quantities of inorganic material fines after separation of
the extract from the bitumen-depleted oil sands material 109. These
inorganic material fines 117 may be separated from the
bitumen-containing extract in a fines separation unit 115. The
fines separation unit 115 may be any conventional mechanical or
physical solid/liquid separator. For example, the fines separation
unit 115 may be a centrifuge or a filter configured to separate
solid particles having the size of the fines in the
bitumen-containing extract from a liquid, for example, the filter
may be an ultrafiltration unit. The separation unit 115 may also be
a settling tank wherein the fines gravitationally settle to the
bottom of the tank for separation from the bitumen-containing
extract, preferably within a period of at most 1 hour, or at most 2
hours, or at most 12 hours, or at most 1 day due to the low
viscosity of the bitumen-containing extract. The inorganic material
fines 117 may be separated from the bitumen-containing extract in
the fines separation unit 115 to produce a substantially
particulate-free bitumen-containing extract 119.
[0052] Alternatively, substantially all of the inorganic solid
particulate material, including the inorganic material fines, may
be separated from the bitumen-containing extract 107 upon
separation of the bitumen-depleted oil sands material 109 from the
bitumen-containing extract 107 due to the low viscosity of the
bitumen-containing extract, particularly if the bitumen-containing
extract is separated from the bitumen-depleted oil sands material
109 in a clarifier. In the process of the present invention, the
bitumen-containing extract 107 separated from the bitumen-depleted
oil sands material 109 may contain at most 500 parts per million
("ppm") by weight, or at most 400 ppm by weight, or at most 250 ppm
by weight, or at most 100 ppm by weight, or at most 50 ppm by
weight of inorganic solid particulate matter. In such cases, the
system of the present invention may require no fines separation
unit 115; and the process of the present invention may require no
separate step of separating inorganic material fines from the
bitumen-containing extract 107 after separation of the
bitumen-containing extract from the bitumen-depleted oil sands
material 109.
[0053] The substantially particulate-free bitumen-containing
extract 119 may be comprised of bitumen and the bitumen solvent.
The bitumen-containing extract 119 may contain at least 90 wt. %,
or at least 95 wt. %, or at least 97 wt. % of the bitumen contained
in the oil sands material 105. More particularly, the bitumen
containing extract 119 may contain substantially all of the
asphaltenes initially contained in the oil sands material 105, for
example, the bitumen-containing extract 119 may contain at least 80
wt. %, or at least 90 wt. %, or at least 95 wt. % of the
asphaltenes initially contained in the oil sands material 105,
including both C.sub.7 asphaltenes and C.sub.5 asphaltenes. The
bitumen-containing extract 119 may contain at least 90 wt. %, or at
least 95 wt. %, or at least 97 wt. % of the C.sub.7 asphaltenes
initially present in the oil sands material 105 and may contain at
least 80 wt. %, or at least 90 wt. %, or at least 95 wt. % of the
C.sub.5 asphaltenes initially contained in the oil sands material
105.
[0054] The bitumen-containing extract 119 may be transported to an
oil processing facility such as a refinery, e.g. in an oil
pipeline, for refining the bitumen into oil products. The bitumen
solvent contained in the bitumen-containing extract may be utilized
as a diluent for ease of transport of the bitumen contained in the
bitumen-containing extract 119. The bitumen solvent may be stripped
from the bitumen-containing extract 119 at the oil processing
facility and returned for further use as the bitumen solvent 101
introduced into the contacting apparatus 103 to capture further
bitumen from an oil sands material 105.
[0055] To facilitate a better understanding of the present
invention, the following examples of certain aspects of some
embodiments are given. In no way should the following examples be
read to limit, or define, the scope of the invention.
EXAMPLE 1
[0056] The quality of dimethyl sulfide as an oil recovery agent
based on the miscibility of dimethyl sulfide with a crude oil
relative to other compounds was evaluated. The miscibility of
dimethyl sulfide, ethyl acetate, o-xylene, carbon disulfide,
chloroform, dichloromethane, tetrahydrofuran, and pentane solvents
with mined oil sands was measured by extracting the oil sands with
the solvents at 10.degree. C. and at 30.degree. C. to determine the
fraction of hydrocarbons extracted from the oil sands by the
solvents. The bitumen content of the mined oil sands was measured
at about 11.5 wt. % as an average of bitumen extraction yield
values for solvents known to effectively extract substantially all
of bitumen from oil sands--in particular chloroform,
dichloromethane, o-xylene, tetrahydrofuran, and carbon disulfide.
One oil sands sample per solvent per extraction temperature was
prepared for extraction, where the solvents used for extraction of
the oil sands samples were dimethyl sulfide, ethyl acetate,
o-xylene, carbon disulfide, chloroform, dichloromethane,
tetrahydrofuran, and pentane. Each oil sands sample was weighed and
placed in a cellulose extraction thimble that was placed on a
porous polyethylene support disk in a jacketed glass cylinder with
a drip rate control valve. Each oil sands sample was then extracted
with a selected solvent at a selected temperature (10.degree. C. or
30.degree. C.) in a cyclic contact and drain experiment, where the
contact time ranged from 15 to 60 minutes. Fresh contacting solvent
was applied and the cyclic extraction repeated until the fluid
drained from the apparatus became pale brown in color.
[0057] The extracted fluids were stripped of solvent using a rotary
evaporator and thereafter vacuum dried to remove residual solvent.
The recovered bitumen samples all had residual solvent present in
the range of from 3 wt. % to 7 wt. %. The residual solids and
extraction thimble were air dried, weighed, and then vacuum dried.
Essentially no weight loss was observed upon vacuum drying the
residual solids, indicating that the solids did not retain either
extraction solvent or easily mobilized water. Collectively, the
weight of the solid or sample and thimble recovered after
extraction plus the quantity of bitumen recovered after extraction
divided by the weight of the initial oil sands sample plus the
thimble provide the mass closure for the extractions. The
calculated percent mass closure of the samples was slightly high
because the recovered bitumen values were not corrected for the 3
wt. % to 7 wt. % residual solvent. The extraction experiment
results are summarized in Table 1.
TABLE-US-00001 TABLE 1 Summary of Extraction Experiments of
Bituminous Oil Sands with Various Fluids Input Output Experimental
Temperature, Solids Solids Weight Recovered Weight Extraction Fluid
C. weight, g weight, g Change, g Bitumen, g Closure, % Carbon
Disulfide 30 151.1 134.74 16.4 16.43 100.0 Carbon Disulfide 10
151.4 134.62 16.8 16.62 99.9 Chloroform 30 153.7 134.3 19.4 18.62
99.5 Chloroform 10 156.2 137.5 18.7 17.85 99.5 Dichloromethane 30
155.8 138.18 17.7 16.30 99.1 Dichloromethane 10 155.2 136.33 18.9
17.66 99.2 o-Xylene 30 156.1 136.58 19.5 17.37 98.6 o-Xylene 10
154.0 136.66 17.3 17.36 100.0 Tetrahydrofuran 30 154.7 136.73 18.0
17.67 99.8 Tetrahydrofuran 10 154.7 136.98 17.7 16.72 99.4 Ethyl
Acetate 30 153.5 135.81 17.7 11.46 96.0 Ethyl Acetate 10 155.7
144.51 11.2 10.32 99.4 Pentane 30 154.0 139.11 14.9 13.49 99.1
Pentane 10 152.7 138.65 14.1 13.03 99.3 Dimethyl Sulfide 30 154.2
137.52 16.7 16.29 99.7 Dimethyl Sulfide 10 151.7 134.77 16.9 16.55
99.7
[0058] FIG. 4 provides a graph plotting the weight percent yield of
extracted bitumen as a function of the extraction fluid at
30.degree. C. applied with a correction factor for residual
extraction fluid in the recovered bitumen, and FIG. 5 provides a
similar graph for extraction at 10.degree. C. without a correction
factor. FIGS. 4 and 5 and Table 1 show that dimethyl sulfide is
comparable for recovering bitumen from an oil sand material with
the best known fluids for recovering bitumen from an oil sand
material--o-xylene, chloroform, carbon disulfide, dichloromethane,
and tetrahydrofuran--and is significantly better than pentane and
ethyl acetate.
[0059] The bitumen samples extracted at 30.degree. C. from each oil
sands sample were evaluated by SARA analysis to determine the
saturates, aromatics, resins, and asphaltenes composition of the
bitumen samples extracted by each solvent. The results are shown in
Table 2.
TABLE-US-00002 TABLE 2 SARA Analysis of Extracted Bitumen Samples
as a Function of Extraction Fluid Oil Composition Normalized Weight
Percent Extraction Fluid Saturates Aromatics Resins Asphaltenes
Ethyl Acetate 21.30 53.72 22.92 2.05 Pentane 22.74 54.16 22.74 0.36
Dichloromethane 15.79 44.77 24.98 14.45 Dimethyl Sulfide 15.49
47.07 24.25 13.19 Carbon Disulfide 18.77 41.89 25.49 13.85 o-Xylene
17.37 46.39 22.28 13.96 Tetrahydrofuran 16.11 45.24 24.38 14.27
Chloroform 15.64 43.56 25.94 14.86
[0060] The SARA analysis showed that pentane and ethyl acetate were
much less effective for extraction of asphaltenes from oil sands
than are the known highly effective bitumen extraction fluids
dichloromethane, carbon disulfide, o-xylene, tetrahydrofuran, and
chloroform. The SARA analysis also showed that dimethyl sulfide has
excellent miscibility properties for even the most difficult
hydrocarbons--asphaltenes.
[0061] The data showed that dimethyl sulfide is generally as good
as the recognized very good bitumen extraction fluids for recovery
of bitumen from oil sands, and is highly compatible with saturates,
aromatics, resins, and asphaltenes.
EXAMPLE 2
[0062] The quality of dimethyl sulfide as an oil recovery agent
based on the crude oil viscosity lowering properties of dimethyl
sulfide was evalulated. Three crude oils having widely disparate
viscosity characteristics--an African Waxy crude, a Middle Eastern
asphaltic crude, and a Canadian asphaltenic crude--were blended
with dimethyl sulfide. A control sample of each crude was prepared
containing no dimethyl sulfide, and samples of each crude were
prepared and blended with dimethyl sulfide to prepare crude samples
containing increasing concentrations of dimethyl sulfide. Each
sample of each of the crudes was heated to 60.degree. C. to
dissolve any waxes therein and to permit weighing of a homogeneous
liquid, weighed, allowed to cool overnight, then blended with a
selected quantity of dimethyl sulfide. The samples of the
crude/dimethyl sulfide blend were then heated to 60.degree. C. and
mixed to ensure homogeneous blending of the dimethyl sulfide in the
samples. Absolute (dynamic) viscosity measurements of each of the
samples were taken using rheometer and closed cup sensor assembly.
Viscosity measurements of each of the samples of the West African
waxy crude and the Middle Eastern asphaltic crude were taken at
20.degree. C., 40.degree. C., 60.degree. C., 80.degree. C., and
then again at 20.degree. C. after cooling from 80.degree. C., where
the second measurement at 20.degree. C. is taken to measure the
viscosity without the presence of waxes since wax formation occurs
slowly enough to permit viscosity measurement at 20.degree. C.
without the presence of wax. Viscosity measurements of each of the
samples of the Canadian asphaltenic crude were taken at 5.degree.
C., 10.degree. C., 20.degree. C., 40.degree. C., 60.degree. C.,
80.degree. C., The measured viscosities for each of the crudes are
shown in Tables 3, 4, and 5 below.
TABLE-US-00003 TABLE 3 Viscosity (mPa s) of West African Waxy Crude
vs. Temperature at Various levels of Dimethyl Sulfide Diluent DMS,
wt. % 20.degree. C. 40.degree. C. 60.degree. C. 80.degree. C.
20.degree. C. 0.00 128.8 34.94 15.84 9.59 114.4 1.21 125.8 30.94
14.66 8.92 100.1 2.48 122.3 30.53 13.66 8.44 89.23 5.03 78.37 20.24
10.45 6.55 55.21 7.60 60.92 17.08 9.29 6.09 40.89 9.95 44.70 13.03
7.58 5.04 30.61 15.13 23.96 8.32 4.97 3.38 17.64 19.30 15.26 6.25
4.05 2.92 12.06
TABLE-US-00004 TABLE 4 Viscosity (mPa s) of Middle Eastern
Asphaltic Crude vs. Temperature at Various levels of Dimethyl
Sulfide Diluent DMS, wt. % 20.degree. C. 40.degree. C. 60.degree.
C. 80.degree. C. 20.degree. C. 0.00 2936.3 502.6 143.6 56.6 2922.7
1.3 1733.8 334.5 106.7 44.6 1624.8 2.6 1026.6 219.9 76.5 34.3 881.1
5.3 496.5 134.2 52.2 25.5 503.5 7.6 288.0 89.4 37.4 19.3 290.0 10.1
150.0 52.4 24.5 13.5 150.5 15.2 59.4 25.2 13.6 8.2 60.7 20.1 29.9
14.8 8.7 5.7 31.0
TABLE-US-00005 TABLE 5 Viscosity (mPa s) of Topped Canadian
asphaltenic Crude vs. Temperature at Various levels of Dimethyl
Sulfide Diluent DMS, wt. % 5.degree. C. 10.degree. C. 20.degree. C.
40.degree. C. 60.degree. C. 80.degree. C. 0.00 579804 28340 3403
732 1.43 212525 14721 2209 538 2.07 134880 10523 1747 427 4.87
28720 3235 985 328 8.01 5799 982 275 106 9.80 2760 571 173 73 14.81
1794 1155 548 159 64 32 19.78 188 69 33 19 29.88 113 81 51 22 13 8
39.61 23 20 14 8 6 4
[0063] FIGS. 6, 7, and 8 show plots of Log [Log(Viscosity)] v. Log
[Temperature K] derived from the measured viscosities in Tables 3,
4, and 5, respectively, illustrating the effect of increasing
concentrations of dimethyl sulfide in lowering the viscosity of the
crude samples.
[0064] The measured viscosities and the plots show that dimethyl
sulfide is effective for significantly lowering the viscosity of a
crude oil over a wide range of initial crude oil viscosities.
[0065] The present invention is well adapted to attain the ends and
advantages mentioned as well as those that are inherent therein.
The particular embodiments disclosed above are illustrative only,
as the present invention may be modified and practiced in different
but equivalent manners apparent to those skilled in the art having
the benefit of the teachings herein. Furthermore, no limitations
are intended to the details of construction or design herein shown,
other than as described in the claims below. While systems and
methods are described in terms of "comprising," "containing," or
"including" various components or steps, the compositions and
methods can also "consist essentially of or "consist of the various
components and steps. Whenever a numerical range with a lower limit
and an upper limit is disclosed, any number and any included range
falling within the range is specifically disclosed. In particular,
every range of values (of the form, "from a to b," or,
equivalently, "from a-b") disclosed herein is to be understood to
set forth every number and range encompassed within the broader
range of values. Whenever a numerical range having a specific lower
limit only, a specific upper limit only, or a specific upper limit
and a specific lower limit is disclosed, the range also includes
any numerical value "about" the specified lower limit and/or the
specified upper limit Also, the terms in the claims have their
plain, ordinary meaning unless otherwise explicitly and clearly
defined by the patentee. Moreover, the indefinite articles "a" or
"an", as used in the claims, are defined herein to mean one or more
than one of the element that it introduces.
* * * * *