Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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Flow Chart of the Process:
The mined ore (tar sand) is crushed to permit more intimate contact between
the
solvent solution and the components within the aaareaate mass
To the mechanically conditioned tar sand is added a solvent A / solvent B (xA:
(1-x)B)
mixture of known pH and lower critical solution temperature (LCST).
The temperature of the mixture is raised above its LCST while a circular
agitation
action and stream of air is infected into the slurry.
t
K ~~ ~~ '~~ :. ~~1~'~1'~~~g~
a a =.,~ H .. 2
Tars and pitches that rise to the top of the
mixture are mechanically separated and
sand is removed from the bottom of the column or cone. Free solvent A: solvent
B (e.g.
10: 90 Butoxy Ethanol: Water) is separated from the inorganic mass by
filtration and
or centrifugation. The remaining entrapped solution (.- 2-6% by weight of the
inorganic
nhasPl is raised to 1 O(1°C in order to recover 100°/., of thp
gutoxv Ethanol by azpotrone
The doubled layered solvent solution is separated into an upper phase (e.g.
60:40
Butoxy Ethanol: Water) which contains a major fraction of the oils and a lower
phase
which contains the settled clays, silts, and some residual oils and
naphthenates.
The inorganics in the lower phase are isolated and
washed with fresh solvent A: solvent B (e.g. 60:40
Butoxy Ethanol).
2
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Specifications / Background of the Invention
This invention relates to the separation and isolation of oil sand aggregates
into
four components: 1) tars and pitches, 2) a kerosene fraction, 3) clays, silts
(particle sizes of less than 80 Vim) and 4) sand (particles sizes of greater
than
80pm).
It is known that oil sands can be separated and oil fractions isolated by one
of
many processes of which the ranked highest to lowest preference is the:
a) CHWE (Clark Hot Water Extraction Process) [1],
b) OSLO HWE (Oslo Hot Water Extraction Process) (2],
c) OSLO CWE (Oslo Cold Water Extraction Process) [2],
d) AOSTRA - Takiuk Process [3],
e) ZEFTE (Zero Fine Tailings Extraction Process) [4], and
f) BITMIN (Counter Current Desander Process) [5].
[1] FTFC (Fine Tailings Fundamentals Consortium) "Vol 4 -29. Laboratory
Experiments on the Clark Process" In: Advances in Oil Sands Tailings Research,
Alberta Department of Energy, Oil Sands and Research Division, Publisher.
[2] FTFC (Fine Tailings Fundamentals Consortium) "Vol 4 -9. OSLO Hot and Cold
Water Extraction Processes" In: Advances in Oil Sands Tailings Research,
Alberta
Department of Energy, Oil Sands and Research Division, Publisher.
[3] FTFC (Fine Tailings Fundamentals Consortium) "Vol 4 -6. AOSTRA - Takiuk
Process" In: Advances in Oil Sands Tailings Research, Alberta Department of
Energy, Oil Sands and Research Division, Publisher.
[4] FTFC (Fine Tailings Fundamentals Consortium) "Vol 4 -8. Zero Fine Tailings
Extraction (ZEFTE)" In: Advances in Oil Sands Tailings Research, Alberta
Department of Energy, Oil Sands and Research Division, Publisher.
CA 02249110 1999-02-16
[5) FTFC (Fine Tailings Fundamentals Consortium) "Vol 4 -8. BITMIN" In:
Advances in Oil Sands Tailings Research, Alberta Department of Energy, Oil
Sands and Research Division, Publisher.
SOME OF THE INHERENT PROBLEMS ASSOCIATED WITH SOME OR ALL OF THE
ABOVE ARE:
Eneray Usage:
The processes require large net input of thermal and / or mechanical
energy.[6]
[6] Strand, W. L.; Canadian Pat. 2 124199 (1992 06 11 )
Tailings and Storage Space:
They also generate large quantities of tailings and require indefinite storage
space. [6]
Bitumen Yields:
Except for the AOSTRA-T Process, unacceptably low yields (54 - 92%) of bitumen
are separable from the tar sands using present day technology. In fact, yields
of
92 - 96% are considered to be high using the present art. [7]
[7) Sparks B.D., Majid A., Woods J.; Canadian Pat. 2 093 142 (1994 09 27)
In this invention yields of 99% are considered low from any and all of the ore
bodies found in Alberta, Canada.
Hence, not only can more oil be squeezed out of less ore but utilization of
the
steps in our invention makes access to the lower grade ores economically
viable.
Water usage:
Again, except for the AOSTRA-T Process, large volumes of water are used in the
extraction of bitumen. On average 0.7 to 3 MT of water are required per Metric
Ton
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of ore (depending on the bitumen content of the ore). The lower the bitumen
content the higher the volume of water required. Presently, in the case of the
12%
bitumen content ore, 420,000 MT of water are required per day of full
operation.[8]
[8] FTFC (Fine Tailings Fundamentals Consortium) "Vol. 2 - 3 " In: Advances in
Oil
Sands Tailings Research, Alberta Department of Energy, Oil Sands and Research
Division, Publisher.
Environmental Concerns:
Because the spent water presently generated contains toxic naphthenates, oil
residues, and fine tailings, storage and containment of the waste waters has
become an integral part of the process. The presently projected required
volume
of settling ponds doubles every 400 days. This is expected to decrease to 300
days when the Aurora mine comes on stream in the year 2004 i.e. 460,000,000 m3
per annum of new storage space for spent water shall be required.
It has been estimated that it will take 100 - 300 years for the colloidal of
the fine
tailings to agglomerate to a soft clay before release of the above mentioned
waters shall be permitted to the environment. " Without further treatment of
the
existing fine failings and without process modifications to reduce the rate of
production of "new" fine failings, by the year 2030, over one billion cubic
meters
of a non-consolidating fine tailings would exist at the bottom of these
lakes."
...since "Containment of the entire water system with fhe operating process is
required as part of the operating license agreement between the Provincial
Government and the two commercial plants."(9, 10]
[9]] FTFC (Fine Tailings Fundamentals Consortium) "Vol. 4 -5. " In: Advances
in
Oil Sands Tailings Research, Alberta Department of Energy, Oil Sands and
Research Division, Publisher.
[10] Mac Kinnon, M. and Sethi, A.; A Comparison of the Physical and Chemical
Properties of fhe Tailings Ponds at the Syncrude and Suncor Oil Sands Plants,
Oil
Sands Our Petroleum future Conference, Edmonton, Alberta, April 4-7, 1993.
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AOSTRA Takiuk Process f111
An advantage of the AT Process is that no toxic tailings are generated. Extra
energy costs incurred by the process are partially offset by elimination of
treatment and maintenance costs of the wastewater containment ponds. Although
the process is self sufficient, the expended energy and specialty equipment
must
be costed against the process. Our process minimizes such cost while providing
the opportunity to sell the energy to the open market.
[11 ] FTFC (Fine Tailings Fundamentals Consortium) "Vol. 4 -10. " In: Advances
in
Oil Sands Tailings Research, Alberta Department of Energy, Oil Sands and
Research Division, Publisher.
SUMMARY OF THE INVENTION
The present invention provides a process whereby trapped and bound bitumen
can be removed from an inorganic agglomerate of various size particles. Upon
detachment and because of the ability of the solvent to physically set up a
phase
mixture system which has inherent density and solubility extremes, tars can be
separated from oils and sand can be separated from clays and silts.
Such solvent mixtures have the ability to separate into biphasic mixtures
simply
by adjusting the temperature of the solution or by changing its inorganic salt
concentration.
The separating solvent solution is an aqueous mixture of lipophilic liquids
that
exhibit a Lower Critical Solution Temperature.
Some liquids exhibit total solubility over a range of concentrations and
temperatures but partition into biphasic systems at specific concentrations
and
temperatures. They possess the specific ability to raise the lipophilic and
hydrophilic characteristics of a solution by simple manipulation of the
process
variables. In other words, simple adjustment of the salt concentration or
temperature greatly expands the separation abilities of the constituent
solvents.
An example is Butoxy Ethanol in water. Solutions of greater than 10% and less
than 60% Butoxy Ethanol will, below approximately 40°C remain in
solution but
partition into a biphasic system above 40°C.
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For example, 100 ml of totally miscible Butoxy Ethanol (density 0.934 g/ml)
will, at
50°C give a biphasic system of 10 mls 60% Butoxy Ethanol in Water as a
top
phase (density 0.92 g/ml) and 90 mls of 10% Butoxy Ethanol in Water as a
bottom
phase (density 0.99 g/ml).
Such phenomena are known as Lower Critical Solution Temperatures. When the
reverse phenomena is exhibited i.e. a biphasic mixture at a low temperature
becomes a single phase at a higher temperature the solvents are said to have a
Higher Critical Solution Temperature (HCST).
The present invention provides a method of separating the organic from the
inorganic phase in tar sands with a recyclable liquid composition whose LCST
is
between 0°C and 100°C comprising:
Sodium silicate
...........................................................................0 -
2.5%
°
Sodium hydroxide
.......................................................................0 - 2.5
/°
Alkyl or di alkyl glycol or di glycol ether and / or
Propyl glycol ether ..................................................
Ingredient dependant
Triethyl amine and / or diethyl methyl and / or dimethyl pyridine and / or
methyl pyridyl and / or methyl piperidene
......................................0 -10%
°
Water
...............................................................................
..........to 100 /°
In preferred embodiments of the inventions the following proportions of
components can be used.
Sodium Hydroxide and/or Sodium Silicate 0-2.5%, preferably 0.5 t0 2.5,
particularly
preferable 1-2%
All glycol ethers 0-100%, preferably 10 to 60 particularly 15 - 25%,
especially 20%.
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ADVANTAGE OF OUR PROCESS OVER THE PAST ART
Some obvious advantages of the process are:
1) Simplicity of the equipment and Reduction in capital
the process costs and
maintenance fees.
2) Raising the recovery rates of the Between 15 and 30,000
hydrocarbon extra
fraction well above 92% barrels per day.
3) Making the raw material source usageSome where between 90
of the and 120
low grade ore (6-10% Bitumen content) B$US.
economically viable
4) Facile separation of the solid hydrocarbonsShort cycle time and
therefore
from their liquid counterparts reduced equipment size
requirements.
5) Concentration of the liquid hydrocarbonLowering the process
fraction by partitioning it between temperature to just above
the two phases 40C.
of the solvent mixture at temperatures
just above
the LCST
6) Generate two separate hydrocarbon Eliminate transportation
streams at of the
the mine site (Asphaltenes and liquid inorganic phases.
hydrocarbons
7) Generate a solvent system which This is more of a pour
has a point than
Freezing point of -10C a freezing point.
8) Work with non - flammable solvents Insurance premiums should
i.e. flash be
points above 100C low.
9) Reduce energy usage Process ores just above
40C
10)Eliminate the need for waste water No toxic waste and no
fine
Containment ponds tailings.
11) Eliminate the projected volumes Holding ponds not needed.
of toxic fine
tails
12) Eliminate the need for Tailings No wastewater.
Oil Recovery
13) Recycle the solvent system in a Recovery of the naphthenates
closed cycle
and thio compounds.
14) Segregation of the mineral clays Recovery of >99% pure
from the sand for silicon
further processing dioxide
15) Provide the opportunity to recover
precious metals
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from the inorganic isolants.
16) Extension of the process to cleaning
up man made
spills
Experimental Example
1 ) To a 6-12% by weight sample of tar sand add an equivalent weight of
greater
than 10% by volume Butoxy Ethanol in Water. The solvent mixture may contain
up to 0.75% of sodium hydroxide and meta sodium silicate respectively.
2) The mixture is stirred and a stream of air introduced while being heated
above
40°C.
3) Heating the mixture above 40°C causes the liquid to separate into
two layers or
phases. The upper layer and lower layers are 60:40 and 10: 90 solutions of
Butoxy Ethanol: Water respectively.
4) Tars and pitches (Asphaltenes) whose densities are less than 0.99 g/cc rise
to
the upper layer. Those which are greater than 0.92 and less than 0.99 g/cc
rise
to the interface between the two layers.
5) The asphaltenes can now be isolated by filtering those, which are suspended
in the liquid, and by skimming those surfaces on which they have been
deposited.
6) The asphaltenes are washed with fresh 60:40 BE: Water and azeotrope dried
by raising their temperature to 100°C. The asphaltenes are further
processed at
the refinery level.
7) Purified sand is found at the bottom of the column or cone. It is washed
with
fresh 60:40 BE: Water to ensure it is bitumen free before being passed through
a centrifugal thickener as is used in the paper industry. The semi dry, silt
free
sand is heated to 100°C in order to azeotropicly recover all butoxy
ethanol. The
purified sand (greater than 99% Si02 ) can be used as an abrasive or by the
glass industry.
8) The clay collects on top of the sand. Agitation and air causes the fine
particles
to separate from the larger sand particles.
9
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9) Within the scope of our experiment we used an aspirator attached to a
Pasteur
pipette to collect the clay. It was washed with 60:40 BE: Water in order to
ensure it was bitumen free before azetoropicly drying it.
10) Depending on the source of the ore, the cleaned clays (mainly kaolinite
and
illite) may have commercial appiicatlons or precious metal extraction
possibilities.
11) The kerosene fraction is found dissolved in the top layer. It is recovered
by
fractional distillation.
12) All recovered solvents and washings are recycled. They can be used "as is"
in
a primary extraction step or after purification by distillation.
13) Bitumen yields of greater than 99% are attainable.
