U.S. patent application number 16/066878 was filed with the patent office on 2019-01-24 for hydrocarbon extraction by oleophilic beads from aqueous mixtures.
The applicant listed for this patent is Thomas Gradek. Invention is credited to Thomas Gradek.
Application Number | 20190023991 16/066878 |
Document ID | / |
Family ID | 59224131 |
Filed Date | 2019-01-24 |
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United States Patent
Application |
20190023991 |
Kind Code |
A1 |
Gradek; Thomas |
January 24, 2019 |
HYDROCARBON EXTRACTION BY OLEOPHILIC BEADS FROM AQUEOUS
MIXTURES
Abstract
A system for the recovery of hydrocarbonaceous material, said
hydrocarbonaceous material being in an aggregate mixture in a water
slurry, said system comprising: (a) a means for centrifuging to
remove liquid material from the slurry so as to obtain a water
phase, a hydrocarbon phase and an aggregate solid phase; (b) a
mixing vessel and means for delivery to said mixing vessel a
measured quantity of said aggregate solids, water and a measure
quantity of buoyant beads having a bare oleophilic surface (c)
agitation means for agitating said aqueous mixture in said mixing
vessel so as to obtain product buoyant beads having
hydrocarbonaceous material associated therewith; and (c) recovery
means for recovering product buoyant beads.
Inventors: |
Gradek; Thomas; (Rosemere,
CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Gradek; Thomas |
Rosemere |
|
CA |
|
|
Family ID: |
59224131 |
Appl. No.: |
16/066878 |
Filed: |
December 30, 2015 |
PCT Filed: |
December 30, 2015 |
PCT NO: |
PCT/CA2015/051382 |
371 Date: |
June 28, 2018 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C10G 33/06 20130101;
C10G 31/10 20130101; C10G 1/045 20130101 |
International
Class: |
C10G 1/04 20060101
C10G001/04; C10G 31/10 20060101 C10G031/10 |
Claims
1. A method for the recovery of hydrocarbonaceous material, said
hydrocarbonaceous material being in an aggregate mixture in a water
slurry, said method comprising the steps of: (a) centrifuging said
aggregate mixture in the water slurry to remove liquid material
from the slurry, so as to obtain a water phase, a hydrocarbon phase
and an aggregate solid phase; (b) agitating said aqueous mixture
comprising water, said hydrocarbonaceous material and buoyant beads
having a bare oleophilic surface so as to obtain product buoyant
beads having hydrocarbonaceous material associated therewith; and
(c) recovering product buoyant beads.
2. A method as defined in claim 1 wherein step (c) comprises a bead
flotation step for the recovery of said product buoyant beads.
3. A method as defined in claim 1 further comprising (d) washing
said product buoyant beads to remove entrained water and/or solids;
and (e) further washing said product buoyant beads from step (c)
with a hydrocarbon solvent so as to recover hydrocarbonaceous
material therefrom so as to obtain solvent washed beads.
4. The method of claim 3, further comprising (e) treating said
solvent washed beads by centrifugation to obtain recovered buoyant
beads having a bare oleophilic surface; and (f) recycling said
recovered buoyant beads.
5. The method of claim 1 wherein said beads have a specific gravity
in the range of from 0.080 to 0.35.
6. The method as claimed in claim 1 wherein said beads have an
average width in the range of from 5 to 20 millimeters.
7. The method as claimed in claim 1 wherein said beads have a
specific gravity in the range of from 0.080 to 0.35 and wherein
said beads have an average width in the range of from 5 to 20
millimeters.
8. A system for the recovery of hydrocarbonaceous material, said
hydrocarbonaceous material being in an aggregate mixture in a water
slurry, said system comprising: (a) a means for centrifuging to
remove liquid material from the slurry so as to obtain a water
phase, a hydrocarbon phase and an aggregate solid phase; (b) a
mixing vessel and means for delivery to said mixing vessel a
measured quantity of said aggregate solids, water and a measure
quantity of buoyant beads having a bare oleophilic surface (c)
agitation means for agitating said aqueous mixture in said mixing
vessel so as to obtain product buoyant beads having
hydrocarbonaceous material associated therewith; and (c) recovery
means for recovering product buoyant beads.
9. A system as defined in claim 8 said recovery means comprises
means for the recovery of said product buoyant beads by bead
flotation.
10. A system as defined in claim 8 further comprising means for
delivering said recovered product buoyant beads to a water wash
means to remove any entrained water and/or solids.
11. A system as defined in claim 10, further comprising air drying
means downstream from said water wash means.
12. A system as defined in claim 11 further comprising bead solvent
wash means downstream from said drying means for contacting said
recovered product buoyant beads with a hydrocarbon solvent so as to
recover therefrom a hydrocarbonaceous material and hydrocarbon
solvent so as to obtain solvent washed beads.
13. A system as defined in claim 12, further comprising means for
treating said solvent washed beads by centrifugation to obtain
recovered buoyant beads having a bare oleophilic surface.
14. A system as defined in claim 13, further comprising means for
recycling said recovered buoyant beads to said mixing vessel.
15. A system as defined in claim 8, further comprising a filter for
filtering waste water from said centrifuge and recycling said
filtered water back to said mixer.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to methods and systems for
recovering fluid type (e.g. liquid) hydrocarbons from both
naturally-occurring and man-made mixtures of hydrocarbons and
mineral substrates; also possibly from mixtures of fluid type (e.g.
liquid) hydrocarbons and water (i.e. no mineral substrates) such
as, for example, from wastewater comprising hydrocarbonaceous
material. In particular, the present invention relates to methods
and systems for processing hydrocarbon-containing geologic material
or ores (including; tar sands, oil sands, oil sandstones, oil
shales) as well as petroleum contaminated soils/and fluids to
recover petroleum-like hydrocarbons, and especially
bitumen/kerogen/and/or crude oil and/or fractions, therefrom and to
render the water and/or mineral substrate residues suitably low in
hydrocarbons, for environmentally-acceptable disposal; and most
particularly to a method and system for separating bitumen from
particulates in tar sand and oil sand-grains, using buoyant
oleophilic beads. As used hereinafter, the term "tar sands" shall
be taken to mean any or all of the above hydrocarbonaceous material
containing ores. As disclosed, for example, in Canadian Patent No.
975,697 issued on Oct. 7, 1975 to Davitt H. James tailing pond
contents, referred to as sludge therein, may be a potential source
of bitumen.
[0002] It is to be understood herein that in relation to the
expression "bare oleophilic surface" and the like, such a (bare)
surface is to be understood as being a "film free or essentially
film free surface" and in particular as being a "surface devoid of
or essentially devoid of any hydrocarbon or solvent (outer) film".
It is in particular to be understood herein that the expressions
"film free or essentially film free surface" and "surface devoid of
or essentially devoid of any hydrocarbon or solvent (outer) film"
and the like are to be understood as qualifying a (bare oleophilic)
surface etc. as being a surface etc. able to be (directly)
associated with a hydrocarbonaceous material (for the purposes) as
described herein, e.g. without the application or intervention of
an intermediate hydrocarbon film or layer being (first) applied to
such surface etc. For example such a surface may be a surface which
has no film of solvent or if such film of solvent is present, it
may be present in essentially not more than 2% solvent weight by
weight of the beads and in particular the amount of solvent
following the drying stage may, for example, be not more than about
0.5% by weight of solvent by weight of the beads.
[0003] In the intended application of attaching hydrocarbonaceous
material to the surface of suitable (buoyant) beads, such beads
associated with hydrocarbonaceous material may, for example, be
made bare of hydrocarbonaceous film by volatilization (e.g. by the
exploitation of heat, vacuum, etc, including combinations thereof,)
of (all) residual hydrocarbon liquids and/or solvents, and/or by
means of centrifuging, and/or by microbial degradation such that
the desired oleophilic properties of the beads is (fully) restored,
enabling them to be reintroduced to the process as recycled, fresh
beads unaltered by any cross-contamination.
[0004] As used herein, the terminology "aggregate component" and
any similar word(ing) shall be understood as referring to or as
characterizing (or emphasizing) a "material", etc. or any portion
thereof as a mass of individual particles or elements of the same
or varied size (e.g. the size of the particles or elements may or
may not be uniform and may range from microscopic granules to 10 cm
and larger); it is also to be understood that the particle size
distribution of any particular "material", etc. may be different
from that of another "material", etc. which is part of an aggregate
component".
[0005] As used herein, the terminology "aggregate component" and
the like shall also be understood as referring to but not limited
to superficial earth crust material, whether natural or man made
(i.e. unconsolidated mantle, soil, etc.), namely aggregate material
including but not limited to aggregate material disposed on dry
land masses (e.g. soil aggregate material); sedimentary aggregate
including any bottom sediments of fresh or marine water systems;
aggregate material which has an organic matter portion derived for
example from tar sands, oil shale, etc.; aggregate material derived
from human activities, such as, for example, mineral aggregate
materials, fill aggregate materials as well as sediments arising in
water-ways; etc.
[0006] Thus as used herein, the terminology "soil" includes all
forms of particulate matter, such as, for example, clay, fines,
sand, rock, humus, etc. and in particular for example, soil
particles and embankment material particles.
[0007] It is to be understood herein that the expression
"hydrocarbonaceous material" or the like is a reference to a liquid
material; such liquid material may have a low (e.g. 1 centipoise)
to (very) high viscosity (e.g. 10.sup.6 centipoise); e.g. a
viscosity in the range of from 10 centipoise to 10.sup.6
centipoise.
[0008] It is further to be understood herein that the expression
"hydrocarbonaceous material" or the like is a reference to
naturally occurring and/or man-made fluid (i.e. liquid) material
including but not limited to hydrocarbon type organic materials. In
general, the expression "hydrocarbonaceous material" or the like is
to be understood as being a reference to any type of organic
material comprising hydrogen and carbon provided that such material
is able to be picked-up by the surface of beads as described
herein; in particular such materials which are (at least partially)
water insoluble or water immiscible. Thus, the expression
"hydrocarbonaceous material" or the like is in particular to be
understood as being a hydrocarbon type organic material consisting
of hydrogen and carbon.
[0009] A "hydrocarbonaceous material" may be associated with
inorganic type (e.g. mineral type) substrates, which may, for
example, constitute in addition to hydrocarbons, oleophilic (solid)
particles. Such oleophilic (solid) particles may be organic, and
may comprise asphaltenes, low grade coal, kerogen, etc. . . . A
"hydrocarbonaceous material" may be found in hydrocarbon-containing
geologic material or ores including tar sands, oils sands, oil
sandstones, oil shales and petroleum contaminated soils.
[0010] It is further understood that the hydrocarbonaceous material
recovered (as described herein) from the product beads by the use
of a hydrocarbon solvent to recover hydrocarbonaceous material
there from (e.g. as a component of a hydrocarbon fluid (i.e.
liquid) mixture comprising recovered hydrocarbonaceous material and
said hydrocarbon solvent), may be suitable for refining and the
amount of hydrocarbon solvent present in the mixture may be such
that the viscosity of the hydrocarbonaceous material may be
manipulated (e.g. reduced) so as to provide an API value of at
least 12 (e.g. an API of 16 or higher) which is suitable for
pipeline transportation to a refinery.
BACKGROUND OF THE INVENTION
[0011] Procedures for separating bitumen from mined oil sands are
known. A hot water method is for example, disclosed in Canadian
Patent No. 841,581 issued May 12, 1979 to Paul H. Floyd, et. al.;
in accordance with this patent bituminous sands are jetted with
steam and mulled with a minor amount of hot water and sodium
hydroxide in a conditioning drum to produce a pulp which passes
from the conditioning drum through a screen which removes debris,
rocks and oversize lumps to a sump where it is diluted with
additional water. It is thereafter carried into a separation
cell.
[0012] In the separation cell, sand settles to the bottom as
tailings which are discarded. Bitumen rises to the top of the cell
in the form of a bituminous froth which is called the primary froth
product. The froth product may be combined with a hydrocarbon
diluent such as naphtha. The resultant mixture may be centrifuged
to obtain a final bitumen product that is suitable for refining
into a synthetic crude oil.
[0013] Various methods for preparing oil sand slurries are also
taught in the prior art; see for example Canadian (CA) Patent No.
918,588 issued on Jan. 9, 1973 to Marshall R. Smith, et. al., and
U.S. Pat. No. 3,968,572 issued on Jul. 13, 1976 to Frederick C.
Stuchberry.
[0014] CA 2212447 discloses the use of oleophilic free bodies and a
hydrocarbon solvent film applied thereto to collect the oil phase
as disclosed in the patent.
[0015] It would, for example, be advantageous to have an alternate
means for recovery of hydrocarbonaceous material from substances
comprising for example different types of (viscous) hydrocarbon
oils and mineral particles. It would in particular be advantageous
to be able to recover bitumen mixtures such as for example mined
tar sand slurries, tar sand tailings, middlings and tailings pond
sludge; viscous hydrocarbons deposited on sands or water surfaces
as a result of oil spills; oil and water emulsions created by steam
injection into tar sands or heavy oil deposits or other oil
recovery techniques; mineral deposits in low grade ores mined dry
and mixed with water or dredged materials from streams, lakes beds,
river bottoms and the like.
[0016] U.S. Pat. No. 8,440,727 discloses a system and method for
recovering hydrocarbonaceous material from either a water or from a
solid base. Furthermore, the amount of material recycled in this
patent could be improved up. It would be advantageous to provide a
system capable of recovering hydrocarbonaceous material from a
slurry, and also to be able to recycle more material.
SUMMARY OF THE INVENTION
[0017] The invention in an aspect relates to the use (e.g. reuse)
of buoyant beads having a (bare) oleophilic surface able to
associate with (i.e. pick-up) hydrocarbonaceous material (e.g.
bituminous material) for recovery thereof. Such (bare) oleophilic
surface has the advantage of being able to take up a wide range of
hydrocarbonaceous material.
[0018] Thus, in a particular aspect the present invention relates
to the use of buoyant beads having a bare oleophilic surface to
recover hydrocarbonaceous material from an aqueous mixture
comprising water and hydrocarbonaceous material.
[0019] The invention in accordance with another aspect exploits a
(hydrocarbon) solvent (e.g. a solvent as described herein--e.g. a
substance comprising toluene, xylene, naphtha, hexane, pentane and
the like as well as mixtures thereof) to recover hydrocarbonaceous
material from product buoyant beads (e.g. as described herein).
However, in accordance with a particular feature of this aspect the
(hydrocarbon) solvent need, for example, not be (e.g. wholly)
separated from the recovered hydrocarbonaceous material for
recycling but may instead be used or exploited to perform the
function of a diluent component to facilitate pumping of recovered
hydrocarbonaceous material to a downstream processing plant or to a
storage tank(s) for subsequent transport to such a downstream
processing plant (i.e. by pipeline or by tanker truck).
[0020] In accordance with the present invention the buoyant beads
(or free bodies) may take any suitable or desired form keeping in
mind the purpose thereof. Thus the buoyant beads may be in the form
of spheres, spheroids, pebbles, teardrops, rods, discs, saddles, or
of another shape, simple or complex, which is effective in
searching out dispersed phase particles in the mixture. The buoyant
beads (e.g. free bodies) may be solid, hollow, or apertured. They
are preferably of a smooth non-porous surface. The buoyant beads
(e.g. free bodies) may be cast, molded, formed or fabricated in
other ways. Oleophilic free bodies may be made with oleophilic
materials or they may be made from other materials and then covered
with a (solid) layer of an oleophilic material.
[0021] Any oleophilic material may be used herein keeping in mind
(see below) that the invention in an aspect relates to the use
(e.g. reuse) of buoyant beads having a "bare" oleophilic surface
able to associate with (i.e. pick-up) hydrocarbonaceous material
(e.g. bituminous material) for recovery thereof. Examples of
suitable oleophilic materials that may be used in the fabrication
of oleophilic buoyant beads of the present invention free bodies
are neoprene, urethane, polypropylene, plastics and artificial
rubbers, see CA patent 1144498, CA patent 2212447, U.S. Pat. No.
3,399,765, U.S. Pat. No. 4,236,995, U.S. Pat. No. 4,406,793, U.S.
Pat. No. 4,511,461, etc.
[0022] The use of oleophilic adhesion techniques of the present
invention may for example be exploited for recovering bitumen from
mined tar sands, for recovering other hydrocarbons from aqueous
mixtures (e.g. from wastewater) and for recovering oleophilic
surfaced mineral particles.
[0023] The present invention in accordance with an aspect thereof
provides a method for the recovery (or separation) of
hydrocarbonaceous material from water, said hydrocarbonaceous
material being a liquid material, said method comprising the steps
of:
[0024] (a) agitating an aqueous mixture comprising water, said
hydrocarbonaceous material and buoyant beads having a bare
oleophilic (i.e. film free or essentially film free) surface (e.g.
a surface devoid of or essentially devoid of any hydrocarbon or
solvent (outer) film, e.g. beads for which at least the (i.e.
exposed/outer) surfaces are of oleophilic material) so as to obtain
product buoyant beads having hydrocarbonaceous material associated
therewith (i.e. buoyant beads to (the (outer) surface of) which
hydrocarbonaceous material is adhered); and (b) recovering product
buoyant beads.
[0025] In accordance with the present invention for step (b) any
suitable or desired recovery technique may be exploited for the
recovery of the product buoyant beads (i.e. keeping in mind the
purpose thereof). Thus, for example, step (b) may comprise a bead
flotation step for the recovery of product buoyant beads; step (b)
may comprise a screening step whereby product beads are separated
(i.e. strained) from other components of the aqueous mixture using
suitable screening means; step (b) may as desired comprise a
combination of these or other (suitable) recovery techniques.
[0026] In accordance with the present invention a method for the
recovery (or separation) of hydrocarbonaceous material may as
desired or necessary further comprise
[0027] (c) contacting product buoyant beads from step (b) with a
hydrocarbon solvent so as to recover hydrocarbonaceous material
therefrom; e.g. so as to recover a hydrocarbon fluid (i.e. liquid)
mixture wherein recovered hydrocarbonaceous material is a component
thereof along with hydrocarbon solvent. The hydrocarbon solvent in
step (c) may for example, comprises at least one compound that is
selected from the group consisting of naphtha, toluene, hexane and
pentane.
[0028] In accordance with the present invention step (c) may also
be carried out so as to also obtain solvent washed beads. The
recovery method may optionally (or as desired or as necessary)
comprise treating solvent washed beads (in any suitable manner) so
as to recover buoyant beads having the above mentioned bare
oleophilic surface. Such recovered bead may as desired or necessary
be recycled for use in step (a) of the recovery method. In other
words as may be understood, solvent washed beads (e.g. beads free
of the sought after hydrocarbonaceous material) may yet be
associated with hydrocarbon solvent. Hence, a method (or system) of
the present invention may further comprise (any type of suitable)
means (e.g. heating) for separating such (retained) solvent from
the solvent washed beads to return the beads to their original
(i.e. bare) state, (i.e. devoid of or essentially devoid of any
residual hydrocarbon or solvent film) for re-use.
[0029] The buoyant beads may be of any suitable material; see
above. The buoyant beads may for example be an organic co-polymer.
The beads may for example be specifically designed and manufactured
for any unique desired characteristics. The polymer of the beads
may be a material having suitable oleophilic and buoyancy
characteristics keeping in mind the purpose thereof; the beads may
as desired also have hydrophobic characteristic. Thus beads may be
used which take the form of a (naturally) hydrophobic and
oleophilic co-polymer.
[0030] In accordance with a particular aspect of the present
invention hydrocarbonaceous material may be recovered from a
hydrocarbon bearing composition comprising an aggregate component
and a hydrocarbon component, the hydrocarbon component comprising
hydrocarbonaceous material. The aggregate component, may be as
defined herein (i.e. above).
[0031] Thus the present invention also relates to a method for the
recovery (or separation) of hydrocarbonaceous material from a
hydrocarbon bearing composition comprising an aggregate component
and a hydrocarbon component, said hydrocarbon component comprising
hydrocarbonaceous material, said hydrocarbonaceous material being a
liquid material, the method comprising: (a) agitating an aqueous
mixture comprising water, said hydrocarbon bearing composition and
buoyant beads having a bare oleophilic (i.e. film free or
essentially film free) surface (e.g. a surface devoid of or
essentially devoid of any hydrocarbon or solvent (outer) film, e.g.
beads for which at least the (i.e. exposed/outer) surfaces are of
oleophilic material), so as to obtain product buoyant beads having
hydrocarbonaceous material associated therewith; (b) recovering
product buoyant beads; and (c) contacting product buoyant beads
from step (b) with a hydrocarbon solvent so as to recover
hydrocarbonaceous material therefrom.
[0032] In accordance with the present invention a method for the
recovery (or separation) of hydrocarbonaceous material from a
hydrocarbon bearing composition is provided wherein step (b)
thereof may comprise a bead flotation step for the recovery of said
product buoyant beads and said product buoyant beads from step (b)
may be contacted with a hydrocarbon solvent so as to recover
hydrocarbonaceous material therefrom.
[0033] In accordance with the present invention a method for the
recovery (or separation) of hydrocarbonaceous material from a
hydrocarbon bearing composition is provided wherein step (b)
thereof may comprise a bead flotation step for the recovery of said
product buoyant beads and said product buoyant beads from step (b)
may be contacted with a hydrocarbon solvent so as to recover
therefrom a liquid hydrocarbon mixture comprising recovered
hydrocarbonaceous material and hydrocarbon solvent and so as to
obtain solvent washed beads
[0034] In accordance with the present invention a method for the
recovery (or separation) of hydrocarbonaceous material from a
hydrocarbon bearing composition is provided wherein the solvent
washed beads may be treated to obtain recovered buoyant beads
having a bare oleophilic surface and said recovered buoyant beads
are recycled to step (a) thereof.
[0035] As mentioned above in accordance with the present invention
the hydrocarbon solvent in step (c) nay comprise at least one
compound that may be selected from the group consisting of naphtha,
toluene, hexane and pentane.
[0036] In accordance with the present invention the buoyant beads
may have a specific gravity in the range of from 0.080 to 0.35.
[0037] In accordance with the present invention the buoyant beads
may have an average width in the range of from 5 to 20
millimeters.
[0038] In accordance with the present invention the buoyant beads
may have a specific gravity in the range of from 0.080 to 0.35 and
an average width in the range of from 5 to 20 millimeters.
[0039] In accordance with another aspect the present invention
relates to a system for the recovery of hydrocarbonaceous material
from water, said hydrocarbonaceous material being a liquid
material, said system comprising:
[0040] (a) a mixing vessel for containing an aqueous mixture
comprising water, hydrocarbonaceous material and buoyant beads
having a bare oleophilic surface (as defined herein)
[0041] (b) agitation means for agitating said aqueous mixture in
said mixing vessel so as to obtain product buoyant beads having
hydrocarbonaceous material associated therewith; and
[0042] (c) recovery means for recovering product buoyant beads.
[0043] A system in accordance with the present invention may
comprise recovery means which comprises means for the recovery of
product buoyant beads by bead flotation (or any other suitable,
desired or necessary technique).
[0044] A system in accordance with the present invention may
further comprise bead solvent wash means for contacting product
buoyant beads with a hydrocarbon solvent so as to recover
hydrocarbonaceous material therefrom. A system in accordance with
the present invention may in particular further comprise bead
solvent wash means for contacting product buoyant beads with a
hydrocarbon solvent so as to recover therefrom a liquid hydrocarbon
mixture comprising recovered hydrocarbonaceous material and
hydrocarbon solvent and so as to obtain solvent washed beads.
[0045] A system in accordance with the present invention may
further comprise means for treating solvent washed beads to obtain
recovered buoyant beads having a bare oleophilic surface (as
defined herein).
[0046] A system in accordance with the present invention may
further comprise means for recycling recovered buoyant beads having
a bare oleophilic surface (as defined herein) to the mixing
vessel.
[0047] The present invention in particular relates to a system for
the recovery of hydrocarbonaceous material from a hydrocarbon
bearing composition comprising an aggregate component and a
hydrocarbon component, said hydrocarbon component comprising
hydrocarbonaceous material said hydrocarbonaceous material being a
liquid material, said system comprising:
[0048] (i) a mixing vessel for containing a mixture comprising
water, said hydrocarbon bearing composition and buoyant beads
having a bare oleophilic surface (as defined herein);
[0049] (ii) agitation means for agitating the mixture in said
vessel so as to obtain product buoyant beads having
hydrocarbonaceous material associated therewith;
[0050] (iii) recovery means for recovering product buoyant
beads;
[0051] (iv) bead solvent wash means for contacting said recovered
product buoyant beads with a hydrocarbon solvent for recovering
therefrom a liquid hydrocarbon mixture comprising recovered
hydrocarbonaceous material and hydrocarbon solvent and so as to
obtain solvent washed beads; (v) treatment means for treating said
solvent washed beads to obtain recovered buoyant beads having a
bare oleophilic surface; and (vi) means for recycling recovered
buoyant beads having a bare oleophilic surface to said mixing
vessel. As mentioned above a recovery means may, for example,
comprise means for the recovery of product buoyant beads by bead
flotation.
[0052] Keeping the above in mind, and alternatively stated, the
present invention relates to
[0053] A system for effecting separation of hydrocarbons from a
hydrocarbon bearing composition comprising an aggregate mixture in
a water slurry in which said hydrocarbons are contained
comprising:
[0054] a means of centrifuging in a 3 phase decanter to remove
liquid material from the slurry, so as to obtain a water phase a
hydrocarbon phase and an aggregate solids phase.
[0055] (ii) a mixing vessel and means for delivery to said mixing
vessel a measured quantity of said aggregate solids, water, and. a
measured quantity of buoyant beads that have (bare) surfaces of
oleophilic material
[0056] (iii) means for agitating the mixture in said vessel so as
to obtain product buoyant beads having hydrocarbonaceous material
associated therewith (i.e., buoyant beads to (the (outer) surface
of) which hydrocarbonaceous material is adhered);
[0057] (iv) means for recovering product buoyant beads (e.g. by
flotation)
[0058] (iva) means for delivering said recovered product buoyant
beads to a water wash means to remove any entrained water/solids
and followed by an optional air drying means leading to a
subsequent solvent wash means for contacting said recovered product
buoyant beads with a hydrocarbon solvent for recovering
hydrocarbonaceous material from said product buoyant beads (e.g. as
a component of a hydrocarbon fluid mixture comprising recovered
hydro carbonaceous material and said hydrocarbon solvent) so as to
obtain solvent washed beads;
[0059] (v) means for recovering (or separating) hydrocarbonaceous
material and/or solvent (e.g. as a hydrocarbon fluid (i.e. liquid)
mixture comprising recovered hydro carbonaceous material and said
hydrocarbon solvent) from said solvent washed beads; and
[0060] (vi) means for treating said solvent washed beads (by
centrifugation) to obtain recovered buoyant beads having an
[0061] (bare) oleophilic (i.e. film free or essentially film free)
surface (e.g. a surface devoid of or essentially devoid of any
hydrocarbon or solvent (outer) film, e.g. beads for which at least
the surfaces are of oleophilic material); and
[0062] (vii) means for recycling said recovered buoyant beads to
said mixing vessel.
[0063] The present invention may be effectively exploited for
recovering (e.g. extracting) hydrocarbon (aceou)s (material) by the
use of (naturally/artificially) buoyant oleophilic (hydrophobic
polymer) beads. The buoyant beads may be solid, hollow or a
cellular core construction with a solid surface. They preferably
have a smooth non-porous surface, which exhibits specific surface
energetic properties that provides a high affinity for
hydrocarbons, low interfacial surface tension with hydrocarbons and
a spreading factor closest to zero with hydrocarbons. Examples of
suitable oleophilic materials that may be used in the fabrication
of oleophilic beads are neoprene, urethane, polypropylene, plastics
and artificial rubbers.
[0064] The buoyant beads may for example be slurried with water and
a soil containing hydrocarbons, e.g. Athabasca Tar Sands, and may
be agitated to ensure thorough contact of the soil with the beads,
the slurry mixture then being allowed to settle. The effect of this
agitation is to cause a certain amount of the hydrocarbon that was
contained in the soil to come into contact with the oleophilic
surface of the beads and to adhere directly to the beads. Upon the
mixture settling out, the beads through their natural buoyancy
float to the top of the mixture from where they are removed to
recover the adhered hydrocarbons.
[0065] Repeated treatment of the soil by this process can result in
a very high rate of recovery of the hydrocarbons.
[0066] In the case of Athabasca Tar Sands, recovery rates of
bitumen in excess of 98% have been achieved. In the case of Fine
tailings effluent, 91% and 85% reduction of bitumen and naphtha
content was obtained. Furthermore this has been done at
temperatures ranging from ambient to 45.degree. C. and without the
use of auxiliary chemicals such as caustic soda, hydrogen peroxide
or hydrocarbon solvents (as is required in some prior art
processes). In the absence of caustic soda, the tailings i.e. the
residual soil or sand, settle quickly so that the water can be
recycled in a very short timeframe.
[0067] The beads which may be used are buoyant (i.e. they may have
a specific gravity that is below 0.5 preferably in the range 0.06
to 0.35, most preferably from 0.08 to 0.25) and are preferably of
substances which are naturally hydrophobic and oleophilic and
display good compression strength and resistance to abrasion.
[0068] The beads can be of any suitable composition that will
provide the required buoyancy and adequate durability. For example
they could comprise hollow bodies of e.g. ceramic or metal, coated
with a continuous layer of oleophilic and hydrophobic material.
However, preferably the beads are of a homogeneous organic polymer
material as described in the preceding paragraph.
[0069] The beads used in the examples hereinafter set forth were of
low density and of roughly spherical shape with an average diameter
of about 17 mm, there being approximately 1500 beads per kilogram
weight. The beads should not be too small since if they are they
would not provide sufficient buoyancy to effect floatation when
coated with adhered bitumen and any contained soil; that is the
surface area to volume ratio would be too high.
[0070] Accordingly, it is preferred that the beads have a size in
the range 12 to 20 mm and a specific gravity in the range 0.080 to
0.35.
[0071] The beads may be of various shapes, e.g. spherical, roughly
spherical, or egg shaped. While round or roughly spherical beads
may be preferable, the shape of the beads is critical, as it must
not comprise of any high energy points which are generated by sharp
edges or ridges on the surface.
[0072] The (hydrocarbon) solvents which may be exploited in
accordance with the present invention may for example be of
aliphatic materials low in aromatic content. (Hydrocarbon) Solvents
are to be preferred which (for example) have a tendency to dissolve
the bitumen so that it can wash off more readily from the polymer
bead surface. Low boiling point solvents are preferable since with
these the evaporation and condensation of the solvent in the
process will require little energy. A solvent may for example be of
an aliphatic material such as an alkane-solvent (hydrocarbon) type
material (such as for example naphtha, pentane and hexane; in
particular naphtha).
[0073] The amount of solvent employed will vary depending upon the
type and solvency strength.
[0074] The method of the present invention offers a number of
advantages as follows: (a) no solvent is required than would be the
case in a conventional solvent extraction process, (b) the process
does not require the application of heat, but rather can be carried
out at normal atmospheric temperatures, and at temperatures ranging
from as low as 0.degree. C., to 60.degree. C. thus reducing the
cost of heating the water and hydrocarbon source material as had
previously been required; (c) after mixing and separation of the
beads, the contained solids settle in the water in a matter of
hours (rather than months or years as is the case with some
existing processes); (d) since the solids settle quickly the water
can be recycled in the process rather than sent to a tailings pond
for extended settling periods; (e) the hydrocarbon depleted soils
can be sufficiently cleansed for reclamation; and (f) the method
can provide hydrocarbon recoveries, which exceeds existing
processes without the need to add chemicals such as caustic soda
which would create further downstream pollution problems.
DESCRIPTION OF THE DRAWINGS
[0075] The invention will further be described, by way of example
only, with reference to the accompanying figures wherein
[0076] FIG. 1 is a schematic representation of an example
hydrocarbon recovery system in accordance with the present
invention having a single mixing/separation stage;
[0077] FIG. 2 is a schematic representation of another example
hydrocarbon recovery system in accordance with the present
invention having two mixing/separation stages;
[0078] FIG. 3 is a schematic representation of a further example
hydrocarbon recovery system in accordance with the present
invention having three mixing/separation stages;
[0079] FIG. 4 is a schematic representation of a further example
hydrocarbon recovery system in accordance with the present
invention having centrifuge and shaker stages;
[0080] FIG. 5 is a schematic representation of the system of FIG. 4
whereby a portion of water is recycled via a filtration
process.
DETAILED DESCRIPTION
[0081] In FIG. 1 (1 stage), the base material which in the example
herein disclosed is Athabasca oil sands fine tailings effluent and
mature fine tailing pond sludge, is mixed in a mixing vessel 1 to
homogenize the blending of the 2 streams and may involve the
addition of water indicated by line 61 which is recycled from the
water treatment vessel 6 comprising a dynamic sand filtration unit.
The blended streams are delivered to mixer 3 as shown by line 13
which measures a specific flow rate of slurry.
[0082] In the vessel 3 the oil sands tailings/water mixture is
further mixed with a measured quantity of said buoyant beads which
are in the bead storage vessel 2 are delivered as indicated by line
23. In the example disclosed the beads are molded polymer beads,
being roughly of rounded shape.
[0083] In the mixer vessel 3 the mixture of oil sands, water and
buoyant beads is thoroughly agitated by a paddle mixer which may
comprise of a single or more shafts onto which are fixed
perpendicular to the shaft, perforated paddles of such means and
dimensions as to seat the buoyant beads, during their immersion
into the aqueous mixture. The rotational speed of the mixer shafts
are within the range of 40-150 rpm. For a duration of between 1 and
10 minutes, the beads are swept throughout the downward sweep of
the paddle in the rotation through the slurry to effect contact
with the hydrocarbon coated particles and hydrocarbons in
suspension. Hence by seating the beads into the paddles we are able
to obtain a prolonged contact time. During this agitation it has
been found that hydrocarbons are extracted from the oil sand
particles in the mixture and become adhered to the beads.
[0084] The beads and slurry during agitation are being displaced
along the length of the mixer towards the other end where the
contents of the vessel 3 flow through an aperture and are displaced
to a settling vessel 4 as indicated by line 34 and are allowed to
separate, whereby during this process the coated beads with adhered
hydrocarbons float to the top, and sand and other heavier
constituents sinking to the bottom and separated from the beads by
a layer of water.
[0085] The recovered solids are moved to the solids underflow
vessel or tank 5 by line 45 plus the water which is directed to the
filtration vessel 6 by the line 46 following which some of the
water may be returned to the primary blending vessel 1 via line 61
and the remaining recovered process water can be returned for use
as process water in the upstream operations via line 62. The
hydrocarbon coated beads are then removed from the vessel 4 and
delivered by a conveyor as indicated by the line 47 to a bead
washing vessel 7. In the vessel 7 the beads are treated with a
hydrocarbon solvent (e.g. naphtha) which removes the adhered
hydrocarbons (together with any contained oleophilic soil solids).
In the vessel 7 the beads with adhered hydrocarbons are delivered
into a reception compartment stage in which the hydrocarbon coated
beads are then conveyed on an incline and subjected to a
counter-flow wash of solvent in a rotating, internally ribbed,
perforated inclined trumel which incorporates wash spray heads
directing solvent onto the beads which are transported upwards in
the ribbed trumel (solvent being supplied through a line 97 from a
solvent tank 9) for a duration (slightly) less than the agitation
that occurs in the mixing vessel 3. The liquid contents of the bead
washing vessel 7 are distinctly separated with the
solvent-recovered hydrocarbon layer floating as the top layer above
a water layer. The beads which end up solvent coated during this
wash stage are allowed to drip dry as they reach the top section of
the inclined trumel and the washed beads (which have a layer of
solvent that may still contain minor amounts of dissolved
oil/hydrocarbons) therefrom are delivered via line 710 to a dryer
unit also known as a solvent extractor vessel 10. For example, any
solvent on the surface of the beads may be stripped from the beads
during the drying process by being subjecting the solvent coated
beads to appropriate temperature and pressure conditions (e.g.
partial vacuum) for the solvent being used. The hydrocarbon layer
consisting of recovered hydrocarbons and solvent is transferred to
the storage tank 8 by the line 78 for further processing. As
desired or necessary additional (i.e. make-up) solvent may be added
to the solvent tank 9 (via line 119 to make-up for any solvent
passing on to storage tank 8. The (pumpable) solvent/recovered
hydrocarbon mixture in tank 8 may be sent via conduit 818 to a
pipeline or by tanker truck or by tanker rail car to a further
processing plant.
[0086] The beads from the dryer unit 10 are transferred to the bead
storage vessel 2 by line 102 following the removal of the solvent
which has restored the bead surface back to its original condition
such that it is clean, bare of hydrocarbonaceous film which would
otherwise interfere with the surface energetics of the bead in
relation to targeted hydrocarbons in the mixing vessel 3 during
agitation as described above so as to remove the majority of the
hydrocarbons from the feedstock delivered from vessel 1.
[0087] As shown in FIG. 1, the beads are moved successively from
left to right from bead storage vessel 2 to the mixer vessel 3 then
to the separation vessel 4, to the bead washing vessel 7 and to the
bead dryer unit 10 to be recycled into the bead storage vessel
2.
[0088] Water passing through the mixer vessel 1, onto mixer vessel
3, then to the separation vessel 4 and after separation by settling
is delivered to the water treatment vessel 6 and can be recycled to
the mixer 1 by line 61 or is redirected to other usage by line
62.
[0089] The cleaned sand and soil and the like from the separation
vessel 5 will have a very low content of hydrocarbons and may be
sent to a landfill site or the like for reclamation by line 51.
[0090] The mixing vessel 1 in which the oil sand material is first
mixed with water may be supplied with water as indicated by the
line 61 if need be. The water in treatment vessel 6 is water
recovered from the separation vessel 4.
[0091] Referring to FIG. 2 (2 stage), the same reference numerals
as mentioned for FIG. 1 are used to refer to the same elements as
in FIG. 1. If the desired amount (e.g. all) of the hydrocarbon
material is not removed from the oil sands in a (1 Stage Process)
comprising a single agitating cycle with mixer vessel 3, it is
contended to add an additional series of mixing/separation process
cycles as deemed necessary in staging an additional mixer vessel
13, separation vessel 14 and separated solids underflow vessel 15
as an additional modular processing step, for a 2 Stage Process.
This setup will comprise of the items that are described in the 1
Stage Process (including as desired or necessary additional (i.e.
make-up) solvent may be added to the solvent tank 9 (via line 119),
i.e. to make-up for any solvent passing on to storage tank 8) along
with this additional modular stage, that will process a slurry that
will be made up of a measured quantity of solids from the separated
solids underflow vessel 5 and delivered to the additional mixer
vessel 13 as indicated by the line 513 and a measured quantity of
water from the separated water treatment vessel 6 as indicated by
the line 613, with a measured quantity of said buoyant beads from
beads storage vessel 2 delivered as indicated by line 213, all of
which are delivered to an additional mixer vessel 13 for an
agitation cycle. The beads and slurry during agitation are being
displaced along the length of the mixer towards the end, where the
contents of the vessel 13 flow through an aperture and are
displaced to a settling vessel 14 as indicated by line 1314 and are
allowed to separate, whereby during this process the coated beads
with adhered hydrocarbons float to the top, and sand and other
heavier constituents sinking to the bottom and separated from the
beads by layer of water.
[0092] The recovered water from the separation vessel 14 is
transferred to the separated water treatment vessel 6 by line 146
and the hydrocarbon coated beads are then removed from the vessel
14 and delivered as indicated by the line 147 to a bead washing
vessel 7. Solids pass via line 1415 to solids underflow vessel or
tank 15.
[0093] In the vessel 7 the hydrocarbon coated beads are treated
with a hydrocarbon solvent which removes the adhered hydrocarbons
(together with any contained oleophilic soil solids). In the vessel
7 the beads with adhered hydrocarbons are delivered into a
reception compartment stage in which the hydrocarbon coated beads
are then conveyed on an incline and subjected to a counter-flow
wash of solvent in a rotating, internally ribbed, perforated
inclined trumel which incorporates wash spray heads directing
solvent onto the beads which are transported upwards in the ribbed
trumel the beads with adhered hydrocarbons are agitated with
solvent (supplied through a line 97 from a solvent tank 9) for a
duration (slightly) less than the agitation that occurs in the
mixing vessels (3, 13). The liquid contents of the bead washing
vessel 7 are distinctly separated with the solvent-recovered
hydrocarbon layer floating as the top layer above a water layer.
The beads which end up solvent coated during this wash stage are
allowed to drip dry as they reach the top section of the inclined
trumel and the washed beads (which have a layer of solvent that may
still contain minor amounts of dissolved oil/hydrocarbons)
therefrom are delivered via line 710 to a dryer unit also known as
a solvent extractor vessel 10. The hydrocarbon layer consisting of
recovered hydrocarbons and solvent is transferred to the storage
tank 8 by the line 78 for further processing. As desired or
necessary additional (i.e. make-up) solvent may be added to the
solvent tank 9 (via line 119), i.e. to make-up for any solvent
passing on to storage tank 8. The (pumpable) solvent/recovered
hydrocarbon mixture in tank 8 may be sent via conduit 818 to a
pipeline or by tanker truck or by tanker rail car to a further
processing plant.
[0094] The beads from the dryer unit 10 are transferred to the bead
storage vessel 2 by line 102 following the removal of the solvent
which has restored the bead surface back to its original condition
in that it is, bare of hydrocarbonaceous film.
[0095] If an additional stage (see FIG. 3) is required to further
remove bitumen from the solids from the separated solids underflow
vessel 15, then in addition to the above configuration, another
stage comprising of an additional series of mixing/separation
process cycles as deemed necessary by staging an additional mixer
vessel 23, separation vessel 24 and separated solids underflow
vessel 25 as an additional modular processing step, for a 3 Stage
Process.
[0096] The 3 stage setup shown in FIG. 3 may comprise the items
that are described in the 2 Stage Process (including as desired or
necessary additional (i.e. make-up) solvent may be added to the
solvent tank 9 (via line 119), i.e. to make-up for any solvent
passing on to storage tank 8) along with this additional modular
stage, that will process a slurry that will be made up of a
measured quantity of solids from the separated solids underflow
vessel 15 whereby such measured quantity of solids are delivered to
an additional mixer vessel 23 by means of line 1523 and a measured
quantity of water is delivered from separated water vessel 6 by
line 623, with a measured quantity of said buoyant beads delivered
as indicated by line 223 from beads storage vessel 2 are delivered
to an additional mixer vessel 23 for an agitation cycle. The beads
and slurry during agitation are being displaced along the length of
the mixer towards the end, where the contents of the vessel 23 flow
through an aperture and are displaced to a settling vessel 24 as
indicated by line 2324 and are allowed to separate, whereby during
this process the coated beads with adhered hydrocarbons float to
the top, and sand and other heavier constituents sinking to the
bottom and separated from the beads by layer of water. The
recovered water from the separation vessel 24 is transferred to the
separated water treatment vessel 6 by line 246 and the hydrocarbon
coated beads are then removed from the vessel 24 and delivered as
indicated by the line 247 to a bead washing vessel 7.
[0097] In the vessel 7 the hydrocarbon coated beads are treated
with a hydrocarbon solvent which removes the adhered hydrocarbons
(together with any contained oleophilic soil solids). In the vessel
7 the beads with adhered hydrocarbons are delivered into a
reception compartment stage in which the hydrocarbon coated beads
are then conveyed on an incline and subjected to a counter-flow
wash of solvent in a rotating, internally ribbed, perforated
inclined trumel which incorporates wash spray heads directing
solvent onto the beads which are transported upwards in the ribbed
trumel. The beads with adhered bitumen are agitated with solvent
(supplied through a line 97 from a solvent tank 9) for a duration
slightly less than the agitation that occurs in the mixing vessels
(3, 13, 23). The liquid contents of the bead washing vessel 7 are
distinctly separated with the solvent-recovered hydrocarbon layer
floating as the top layer above a water layer. The beads which end
up solvent coated during this wash stage are allowed to drip dry as
they reach the top section and the beads therefrom are advanced to
a bead dryer via line 710 also known as a solvent extractor vessel
10. The hydrocarbon layer consisting of recovered hydrocarbons and
solvent is transferred to the storage tank 8 by the line 78 for
further processing. In terms of further processing it may be
suitable to pre-treat the recovered hydrocarbon/solvent solution
that is in tank 8 so as to adjust the solvent concentration in
order to meet the pipeline specs of the refinery. This may involve
stripping naphtha from the recovered hydrocarbons by transferring
to vessel 18 the hydrocarbons by line 818, recovering the solvent
and transferring to the solvent storage vessel 9 by line 189 and
then pipeline the hydrocarbons from vessel 18 by line 1833 onto an
oil storage facility illustrated by vessel 33.
[0098] From the vessel 7, the beads therefrom (the washed beads
which have a layer of solvent that may still contain minor amounts
of dissolved oil/hydrocarbons) are delivered via the line 710 to a
dryer unit also known as a solvent extractor vessel 10. The beads
from the dryer unit 10 are transferred to the bead storage vessel 2
by line 102 following the removal of the solvent which has restored
the bead surface back to its original condition in that it is, bare
of hydrocarbonaceous film.
[0099] In this way, under suitable circumstances successive cycles
have removed up to 99% of the hydrocarbons contained in the oil
sands, the resulting cleaned soil material from the separation
vessel 25 will have a very low content of hydrocarbons and may be
sent to a landfill site or the like for reclamation. Solids pass
via line 2425 to solids underflow vessel or tank 25. If required it
may be advantageous to remove further entrained water from the
recovered clean sands by means of a hydrocyclone 31 which is fed by
line 2531. The resulting product will comprise a free flowing tan
coloured granular material with a very low hydrocarbon content and
virtually no solvent content. The recovered water from the
hydrocyclone can be transferred into a water tank 32 by line 3132
and supplement the recycled water volume that may be required in
vessel 1.
[0100] With a single agitation cycle lasting from 1-10 minutes in
the mixer vessel 3 it has been found possible to remove as much as
87% of the bitumen from the high grade oil sands at a temperature
of 20.degree. C. and 72% bitumen for low grade of ore.
[0101] FIG. 4 is a schematic of another embodiment of the
hydrocarbon recovery system in accordance with the present
invention having a single mixer/separation stage, with a shaker
being used in place of the separate bead washing and drying stages.
This embodiment, has many of the same elements and processes as
described for FIG. 1, but has the following modifications. Elements
numbered the same in FIG. 4 as in FIG. 1 are not described again,
and reference may be made to the foregoing description of FIG. 1
for a full identification of these elements.
[0102] In this embodiment ("Shaker Configuration"), feed slurry
from mixing vessel 1 travels to 3-phase decanter centrifuge 402,
before the recovered solids travel to mixer 3 shown by line 23,
along with recovered water 414. Recovered hydrocarbonaceous
material 218 can be cycled back into the process as described with
respect to earlier embodiments.
[0103] In the above described process for FIG. 1, after the
separation process, the hydrocarbon beads are removed from vessel 4
and delivered by conveyor 47. In the Shaker Configuration, the bead
washing vessel 7 and dryer unit 10 are replaced by shaker 407 and
centrifuge 410.
[0104] Shaker 7 may be an inclined vibrating screen, with
compartmentalized troughs to segregate the water and solids in the
water wash and air drying section back into the slurry either in
the mixer or in the 2-phase centrifuge 411.
[0105] The solvent wash bearing hydrocarbonaceous material from the
bead surface is used as a carrier fluid to assist in entrainment of
the beads into the centrifuge 410. The carrier fluid improves the
extraction efficiency of the centrifuge 410, and buffers the beads
as they enter into the centrifuge 410 via line 710. The recovered
hydrocarbons and solvent are sent from centrifuge 410 to storage
tank 8.
[0106] More generally, the Shaker Configuration includes a system
for effecting separation of hydrocarbons from a hydrocarbon bearing
composition comprising an aggregate mixture in a water slurry in
which said hydrocarbons are contained including
[0107] (iii) a means of centrifuging in a 3 phase decanter to
remove liquid material from the slurry, so as to obtain a water
phase a hydrocarbon phase and an aggregate solids phase.
[0108] (iv) a mixing vessel and means for delivery to said mixing
vessel a measured quantity of said aggregate solids, water, and. a
measured quantity of buoyant beads that have (bare) surfaces of
oleophilic material
[0109] (iii) means for agitating the mixture in said vessel so as
to obtain product buoyant beads having hydrocarbonaceous material
associated therewith (i.e, buoyant beads to (the (outer) surface
of) which hydrocarbonaceous material is adhered);
[0110] (iv) means for recovering product buoyant beads (e.g. by
flotation)
[0111] (v) means for delivering said recovered product buoyant
beads to a water wash means to remove any entrained water/solids
and followed by an optional air drying means leading to a
subsequent solvent wash means for contacting said recovered product
buoyant beads with a hydrocarbon solvent for recovering
hydrocarbonaceous material from said product buoyant beads (e.g. as
a component of a hydrocarbon fluid mixture comprising recovered
hydro carbonaceous material and said hydrocarbon solvent) so as to
obtain solvent washed beads;
[0112] (v) means for recovering (or separating) hydrocarbonaceous
material and/or solvent (e.g. as a hydrocarbon fluid (i.e. liquid)
mixture comprising recovered hydro carbonaceous material and said
hydrocarbon solvent) from said solvent washed beads; and
[0113] (vi) means for treating said solvent washed beads (by
centrifugation) to obtain recovered buoyant beads having a bare
oleophilic (i.e. film free or essentially film free) surface (e.g.
a surface devoid of or essentially devoid of any hydrocarbon or
solvent (outer) film, e.g. beads for which at least the surfaces
are of oleophilic material); and
[0114] (vii) means for recycling said recovered buoyant beads to
said mixing vessel.
[0115] FIG. 5 shows another embodiment of the Shaker Configuration
with additional elements added after the separated water treatment
stage. Referring to FIG. 5, the same reference numerals as
mentioned for FIG. 4 are used to refer to the same elements as in
FIG. 4.
[0116] The process is similar to what is described above, but has
the following modifications: water flows from the separation
process to the filtration vessel 6. Rather than the water returning
to primary blending vessel 1 through line 61 and to upstream
operations through line 62, the recovered processed water is sent
to water filtration vessel 514 via line 614.
[0117] Filtration vessel 514 provides filtration for water leaving
the decanter centrifuge 402 and/or the separation process such that
it can be recycled back into the feed slurry 1. Recovered water
from the 3-phase decanter centrifuge 402 also flows to the
filtration vessel 514 via line 214 rather than going to mixer
3.
[0118] Recovery rates are dependent upon a number of factors as
will be discussed more fully below:
(a) Base Material
[0119] This may comprise various forms of oil sands, oil sands
effluent, hydrocarbonaceous shales, heavy oils, produced oil field
wastes, refinery slop, wastewater, tank bottom sludge and various
types of soil which may have been contaminated e.g. as a result of
spillages of hydrocarbon or natural seepages of hydrocarbon.
(b) Solvent
[0120] The process can be operated with various solvents for
extracting hydrocarbon material such as bitumen or crude oil from
the buoyant bead material. Preferred solvents are hydrocarbons
which are available at relatively low costs from an oil refinery,
examples being preferably naphtha, pentane and hexane. For bitumen
recovery it has been found that solvents which are lower in
aromatics (naphtha) are preferable since they tend to have a good
solvency towards the bitumen and cause it to wash off the bead.
Lower boiling point solvents are preferable as less energy is
required to flash off the solvent and recycle the solvent in the
process.
(c) Solvent Quantity
[0121] The optimum quantity of solvent used will depend upon the
solvent type and also on the type of material being extracted. In
practice the amount of solvent used has been determined by allowing
the solvent coated beads to drain naturally in a perforated
container for a period in the order of 5-15 minutes. It has also
been demonstrated that a fine spray at low pressure will dissolve
the hydrocarbon coating very rapidly, thereby reducing the
residence time period. In these circumstances it would be expected
that the beads would retain more of the higher viscosity solvents
as the solvent layer thickness would increase with viscosity. The
ratio of solvent weight to the weight of the beads following the
wash process has been determined to be varying with viscosity from
about 2% to 11% by weight. Preferably the amount of solvent
following the drying stage should be not more than about 0.5% by
weight of the beads.
(d) Temperature.
[0122] The optimum temperature for extraction can be determined by
experimentation. For extraction of bitumen containing oil sands,
evaluations were made by conducting agitation in the mixer vessel 3
at different temperatures. For a single agitation cycle the
following results were obtained:
TABLE-US-00001 Percentage the Temperature C. External all states
Agitation Temperature Percentage of 20 87 40 96 indicates data
missing or illegible when filed
[0123] In a pilot plant system of apparatus for carrying out the
invention applicant has used a twin shaft mixer machine designed by
BHS Gmbh. This machine has six paddles on each shaft which rotate
counter to each other in the direction of rotating from the center
outwards to the sidewalls of the mixer body, having a capacity of
about 200 liters and being equipped with an electronic speed
control that operates at speeds in the range 40-150 rpm. About 12
kilograms of oil sands with approximately 10% hydrocarbonaceous
material and various amounts of beads were added to the mixer
together with approximately 80 liters of 30.degree. C. water and
agitated for times ranging between 5 minutes and 30 minutes. At the
end of agitation the coated beads were scooped from the top of the
mixer and the remaining slurry discharged from the bottom of the
mixer.
[0124] The resulting residual hydrocarbon concentration of the sand
was below 100 ppm and the residual hydrocarbon concentration in the
processed water was below 15 ppm.
[0125] Similar testing on tailing pond sludge with an initial
concentration of 21,000 ppm that were mixed with water to a final
temperature of 35.degree. C. resulted in residual hydrocarbon
levels of <1100 ppm in the solids and residual hydrocarbon
concentration in the process tailing water <402 ppm.
[0126] In a similar test conducted at a temperature of 42.degree.
C., on produced sand from heavy oil operations with an initial
concentration of 25,000 ppm, the resulting residual hydrocarbon
concentration of the sand was below 100 ppm and the residual
hydrocarbon concentration in the processed water was below 1
ppm.
[0127] Although that which is described in the foregoing, is solely
in relation to the recovery of hydrocarbons from soils, it will be
understood that other applications are envisaged for the invention.
For example it is believed that the use of the oleophilic beads as
described above would be effective for removing oil from oil
polluted waters, when the beads are in contact with the oil/water
mixture. Likewise the invention could be used for recovering
hydrocarbons from oily wastes from oil production operations such
as produced sand.
* * * * *