Note: Descriptions are shown in the official language in which they were submitted.
11444~8
B~CK~ROUND 0~ THE INVENTION
This application is based on Caveat No. 31,891 filed
October 11, 1979.
The present invention relates to a method for treat-
ing an oil and water mixture of continuous phase and
dispersed phase so as to facilitate subsequent separation of
the phases. The intent of the present invention is to in-
crease the average s1ze of dispersed phase volumes in the
mixture under treatment.
This invention is primarily concerned with recovering
bitumen or oil phase from oil and water mixtures produced
from oil wells and oil or tar sands. Extensive deposits
of oil sands, which are also known as tar sands and bitu-
minous sands, are found in Northern Alberta, Canada. The
sands are composed of siliceous material with grains gener-
ally having a size greater than that passing a 325 mesh
screen (44 microns) and a reIatively heavy, viscous petrol-
eum called bitumen which fills the voids between the grains
in quantities o~ ~rom 5 to 21 percent of total composition.
(All percentages referred to herein are in weight percent
unless noted otherwise). Generally the bitumen content of
the sand is between 5 and 15 percent. This bitumen contains
typically 4.5 percent sulfur and 38 percent aromatics. Its
specific gravity at 60 F. ranges generally from about 1.00
.,
to about 1.06. The oil sands also contain clay and silt.
Silt is defined as siliceous material which will pass a 325
..
` mesh screen, but which is larger than 2 microns. Clay is
--2--
~1~4~38
material smaller than 2 microns including some siliceous
material of that size. Extensive oil sand deposits are also
found elsewhere in the world such as in the Orinoco heavy
oil belt of Venezuela and in the area near Vernal, Utah.
The mineral and bitumen of these deposits differ somewhat
from those of the Alberta deposits. Compared with the
Alberta oil sands, the Utah deposit contains a coarser sand,
less clay and an even more viscous bitumen.
Much of the world resource of bitumen and heavy oil
is deeply buried by overburden. For example, it has been
estimated that only about 10 percent of the Alberta oil sand
deposit is close enough to the earth's surface to be conven-
iently recovered by mining. The remainder is buried too
deeply to be economically surface mined. Hydraulic mining or
tunnel mining has been proposed for these deeper deposits.
Generally, however, it is considered that enhanced recovery
by steam injection, by injection of aqueous solutions, and/or
by in situ combustion may possibly be more effective for ob-
taining bitumen or heavy oil from deeply burled formations.
Such enhanced recovery methods use one or more oil wells
that penetrate the formation and stimulate or recover the
resource. Recovery of bitumen from a well by steam stimula-
tion is described in Canadian Patent No. 822,985 granted on
September 16, 1969 to Fred D. Muggee. Depending upon the
procedure employed, enhanced recovery methods may produce
mixtures of oil, water and water-in-oil emulsions or produce
oil-in-water emulsions.
~1~4~8
There are several well-known procedures for separating
bitumen from mined oil sands. In a hot water method such as
disclosed in Canadian Patent No. 841,581 issued May 12, 1979
to Paul H. Floyd, et. al., the 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 hereafter
carried into a separation cell.
In the separation cell, sand settles to the bottom as
tailings whlch are discarded. Bitumen rises to the top of
the cell in the form of a bituminous froth which is called
the primary froth product. An aqueous middlings layer con-
taining some mineral and bitumen is formed between these
layers. A scavenging step is normally conducted on this
,
middlings layer in a separate flotation zone. In this
scavenging step, the middlings are aerated so as to produce
a scavenger tailings product, which is discarded, and a
scavenger froth product. The scavenger froth product is
thereafter treated to remove some of its high water and
mlneral matter content and is thereafter combined with the
primary froth product for further treatment. This combined
froth product typically contains about 52 percent bitumen,
6 percent minerals, 41 percent water, all by weight, and
may contain from 20 to 70 volume percent air. It resembles
a liquid foam that is difficult to pump and~ for that reason,
is usually treated with steam to improve its flow character-
istics.
-4-
The higil water and mineral contents of the combined
froth product normally are reduced by diluting it wi-th a
hydrocarbon diluent such as naphtha. It is then centrifuged
to produce a tailings product and a final bitumen product
that typically contains essentially no water and about 1.3
percent solids and that is suitable for coking, hydrovis-
breaking and other refining techniques for producing a
syntketic crude oil. The tailings products, containing some
naphtha, are discarded.
There are basically four effluent streams from the Hot
Water Process. Each carries with it some of the bitumen of
the feed thereby reducing the efficiency of the process.
These include the oversize material, the sand from the sepa-
ration cells, the silt and clay from the scavenger cells and
the tailings from the centrifuges. Up to 10 percent of the
bitumen in the original feed and up to 2 1/2 percent of the
naphtha stream may be lost in this manner. Much of this bitu-
men effluent finds its way into large retention ponds that
are typical of the Hot Water Process. The bottom of one such
retention pond may contain up to 50 percent dispersed mineral
matter substantially of clay and silt as well as 5 percent
bitumen. As disclosed in Canadian Paten-t No. 975,697
issued on October 7, 1975 to Davitt H. James this part of the
pond contents, referred to as sludge, is a potential source
of bitumen.
The ~ot Water Process described in the preceding para-
graphs separates bitumen from a prepared oil sand slurry.
Various methods for preparing oil sand slurries are taught
--5--
in the prior art, as for example disclosed in Canadian Patent
~o. 918,5&8 issued on January ~ 73 to Marshall R. Smith,
et. al., and in U. S. Patent No. 3J968J572 issued on July 13,
1976 to Frederick C. Stuchberry. These apparatus as d~s-
closed were especially designed to form a slurry that is hot,
that contains finely dispersed air bubbles and wherein the
bitumen is in the form of small flecks. Such a slurry is
amenable to subsequent separation in a hot water bath after
dilution wherein bitumen forms into a froth that rises to
the top of the bath and is skimmed therefrom. Alkaline
reagents such as sodium hydroxide are normally added in this
process to give to the slurry those properties that provide
for efficientSeparation of the bitumen i.n said water bath.
However, in the presence of sodium hydroxide, fine clay
particles in the effluent streams from this process do not
settle readily. For this reason inordinately large settling
ponds are required to contain the effluents from commercial
hot water oil sands extraction plants.
The present invention applies to a method of treating
various streams from oil sand opera-tions having a dispersed
oil or aqueous phase to cause combination of dispersed par-
ticles,which combination improves the recovery o~ the oil
phase by the use of apertured oleophilic endless conveyor
belts to achieve oi.l phase aqueous phase separations. These
processes are superior to the Hot Water Process because
separations are conducted at lower process tempera-tures and
with lower water requirements. For comparable oil sand
feedstocks, the bitumen produced by combination of dispersed
--6--
phase particles followed by oil phase-aqueous phase separation
with an apertured oleophilic belt as typically disclosed con-
tains less water than the froth produced by a Hot Water Process.
The apertured oleophilic conveyor belt, that may be
used to separate emulsions, slurries, or mixtures of oil
phase and aqueous phase, typically consists of a mesh belt
that is woven from fibre, string or wire of high tensile
strength and fatigue resistance, that is oleophilic by
nature or that will bond strongly with a belt coatlng that
is oleophilic. This belt typically is supported by two
conveyor end rolls that provide tension and form to the belt.
Separation is achieved by passing a slurry, emulsion or mixture
of oil phase and water phase, with or without particulate
solids, through the belt one or more times. Water phas~ and
particulate solids in the water phase pass through the belt
apertures and are discarded while oil phase attaches itself
to the belt because of its attraction Eor -the oleophilic belt
surfaces. The oil phase subsequently is recovered from said
belt as a product. Typical processes are disclosed in copending
patent applications Serial No. 333,640 filed August 13, 1979 and
Serial No. 333,641 filed August 13, 1979.
BRIEF DESCRIPTION OF THE INVENTION
.... _
In accordance with the broadest concepts of the present
invention, a water and oil mixture of continuous phase and
dispersed phase in the presence of a hydrocarbon diluent is
tumbled with free bodies in a horizontal ro-tating drum to
deaerate the mixture and reduce the viscosity of the oil
phase thereby promoting migration of particulate matter to
the aqueous phase and also promoting the combining of dispersed
7 -
1~ 498
phase volumes to prepare a mixture suitable for separation
by an oleophilic apertured endless conveyor belt or other
means.
The method which is claimed as the invention
- herein is a method for preparing a mixture of aqueous phase
and oil phase for separation. One of the phases is disbursed
and the other is continuous. The method comprises the steps
of: introducing the mixture into a generally horizontally
rotating drum containing a hydrocarbon diluent and free
bodies that tumble in the drum, at least some of the free
bodies having oleophilic surfaces that have affinity for the
oil phase of the mixture; agitating the mixture, diluent and
free bodies in the rotating drum such that the free bodies
continually mix with the mixture and diluent causing the diluent
to unite with the oil phase of the mixture and causing the
dispersed phase volumes of the mixture to unite and grow into
larger sized volumesi removing the diluted oil phase and
aqueous phase from the drum for subsequent separation into a
separate oil phase product and a separate aqueous phase product.
Additional features of alternative embodiments of the invention
are set out in the claims appended hereto.
The free bodies of the present invention are spheres,
or more complex bodies, with surfaces that have affinity for
dispersed phase particles. When tumbled in a drum together with
a froth or emulsion in the presence of a hydrocarbon diluent
these free bodies cause particle size growth of the dispersed
phase in this drum and promote phase separation. The use of
free bodies for separation of oil and water phase without
the use of a hydrocarbon diluent is the subject of copending
patent application, Serial No. 333,832 filed August 15, 1979.
In one embodiment of the present invention, a continuous
feed of bitumen froth, or a water-in-oil emulsion with added
hydrocarbon diluent is tumbled in a drum with free bodies (at
least a portion of which have hydrophilic surfaces) to produce
a continuous bitumen or oil phase product with reduced air
content and/or wherein the dispersed aqueous phase particles
have grown in size.
In a second embodiment, a continuous feed of oil~ln-
water emulsion, obtained from enhanced oil well or bitumen
recovery, is tumbled in a drum with hydrocarbon diluent,
other reagents and oleophilic free bodies to produce a
- 8a -
product of oil phase droplets and streamers in a con-tinuous
wa-ter phase.
Follo~ving is a partial list of feedstocks which may
be treated according to the present inven-tion:
1. A bituminous froth such as from the primary froth
product or from the scavenger froth produc~ of a hot water
oil sand extraction plant in a combination of both fro-th
products.
2. The middlings drag stream of a hot water oil sands
extraction plant containing dispersed bitumen particles.
3. One or more of the effluent streams of a hot water
oil sands extraction plant containing dispersed bitumen
particles.
4. Oil-in-water and/or water-in-oil emulsions pro-
duced from oil shale, either from mined oi] shale or from
in situ production of oil from oil shale.
5. Oil-in-water and/or water in-oil emulsions, such
as may have been obtained by enhanced oil recovery methods,
tar sand operations, in situ bitumen recc)very and the like.
6. A water-in-oil emulsion containing dispersed
water-wet mineral particles.
7. A combination of two or more of the above sources
in one operation.
It is, -therefore, an ob~ject of the present invelltion
to provide a process for the breaking of emulsions and
reduction of air in froths in the processing aqueous bitumen
mixtures which result in increased particle siæes of the dis-
persed phase enabling more efficient oil phase-aqueous phase
separations.
It is also an obJect of the present in-vention to pro-
Yide a process which will reduce the ~-iscosity of oil phase
thereby promoting aqueous phase combination and the transfer
of particulate matter to the aqueous phase.
It is also an object of the present invention -to pro-
vide a process which may lower the temperature at which water
phase-oi7 phase separation may take place effectively under
conditions of enhanced interfacial tension between the
phases.
DRAWINGS
Figure 1 is a perspective view showing the horizontal
drum used in the present invention to tumble an oil phase-
water phase feed with free bodies and hydrocarbon diluent
for the purpose of increasing the size of dispersed phase
particles.
Figure 2 is a cross sectional view of the drum of
Eigure 1 taken along the lines 2 - 2 O:e Figure 1 showing -the
contents of the drum and product flow through the drum.
D:ETAILED DESCRIPTION OE T~IE INVENTION
As used in the present invention "water-in-oil emul-
sion", "oil phase" and "bitumen" all refer to fossil-based
oils that may contain water droplets and particulate solids.
"Bitumen froth" refers to bitumen that contains aqueous phase
and solids, and significant quanti-ties of entrained gas.
"Oil-in-water emulsion" refers -to a stable mixture of small
oil phase droplets dispersed in a continuous aqueous phase
and may contain up to about 5 percent particulate solids.
--10--
"Slurry" refers to a mixture containing continuous water
phase, dispersed oil phase and more -than 5 percent particu-
late solids. "Aqueous phase" refers to any type of ~ater
phase, which is continuous or dispersed and may contain par-
ticulate solids, oil particles and/or chemicals. "Dispersed
phase" refers to that phase in the mixture, emulsion or slurry
thatis not continuous.
It is to be understood -chat the present invention is
to prepare mixtures of heavy or light oil and water,which
may or may not contain particulate solids,for separation.
For example, Canadian Patent No. 726,683 issued on January 25,
1966 to Albert F. Lenhart discloses that oils derived from
solid carbonaceous materials, such as from oil shales, coals,
and the like, usually are recovered in the form of oil-water
emulsions when in-situ combustion is practiced to convert
these solid carbonaceous materials to oils. That same patent
also discloses that in the recovery of conventional crude oil
from wells, oil-water emulsions are produced as well on many
occasions. A paper by L. S. Johnson, et.al. o~ the United
States Department of Energy presented at the 13th Inter-
society Energy Conversion Engineering Conference in San Diego,
California on August 20-25, 1978 discloses that oil-water
emulsions containing particulate solids usually are produced
when oil is recovered by in-situ combustion of tar sands.
In some cases, it has been found to be desirable to
add a hydrocarbon diluent to certain mixtures of oil phase
and aqueous phase prior to or during treatment in a rotating
drum in the presence of free bodies. The addition of
--11--
q3~
hydrocarbon diluen-t to the mixture reduces the viscosity
and density of the oil phase of said mixture. The addition
of a hydrocarbon diluent also permits treatment of such a
mi~ture at a lower ternperature. It is ~nown by those
familiar in the art that, in the range from room temperature
to the temperature of boiling water, the interfacial tension
between bitumen and water decreases with an increase in
temperature. Adding a hydrocarbon diluent to said mixture
may permit treatment of said mixture at a lower tempera-ture
and under conditions of higher interfacial tension, providing
for more effective separation or for more effective particle
size growth of the dispersed phase of the mixture.
For mixtures consisting of an oil in water emulsion,
the hydrocarbon diluen-t by itself is not used to collect the
dispersed phase of the mixture. Rather, said diluent is used
to assist the free bodies to increase the particle size of
the dispersed oil phase in said mixture into oil droplets
or oil bodies to permit more effective subsequent separation.
~ or mixtures consisting of a water in oil emulsion,
the hydrocarbon diluent serves to reduce the viscosity and
density of the continuous oil phase of the mixture and
thereby may permit the free bodies to achieve a more effec-
tive separation of the dispersed water wet solids and water
particles out of the oil phase into larger drops or bodies
of aqueous phase. Separation of the oil phase and aqueous
phase products that leave -the drum of the present invention
may be done subsequently by means of an oleophilic sieve, by
means of an apertured oleophilic conveyor belt, by rneans of
-12-
settling with the use of -the force of gravity or with t'ne use
of centrifugal force such as with centrifuges or hydrocyclones.
Additions of hydrocarbon diluent to the drum of the present
invention may reduce the viscosity of the oil phase of the
mixture under treatment in the drum and may also reduce the
density of said oil phase and thus may provide for effective
settling and separation of the aqueous phase from the oil
phase after removal from said drum.
On occasion, when an oil in water emulsion is in the
process of being broken, a double emulsion may form in the
drum of the present invention. This double emulsion consists
of small aqueous phase particles trapped in larger oil phase
particles that are dispersed in the continuous aqueous phase
contained in said drum. Addition of` hydrocarbon diluent to
said drum will, in many cases, reduce the formation of such
double emulsions and will provide for more effective separa-
tion of water phase from oil phase.
The amount of diluent added to the mixture of the drum
may preferably ran~e from one part diluent and one hunclred
parts oil in the mixture to ten parts diluent and one part
oil in the mixture. When a diluent is used, the preferred
range of viscosity of the resulting oil phase of the mixture
agitating in the drum is within the range of 0.01 to 500
poises.
When the mixture to be trea-ted by the drum and the
free bodies of the present invention consist of a bitumen
froth, such as may be produced for example by the Hot Water
E~traction Process from mined oil sand in the form of a
-13-
~4~8
primary froth product or a scavenger froth product, the dil-
uent added to the mixture as described above will also aid
in the collapse of air bubbles in said mixture.
The present invention takes advantage of these dis-
coveries to prepare mixtures of dispersed phase and continu-
ous phase for separation by an apertured oleophilic belt or
other appropriate means.
Figures 1 and 2 illustrate an apparatus for treating,
with free bodies and added hydrocarbon diluent, a continuous
feed mixture of oil phase and aqueous phase to remove en-
trapped air and to enlarge the particle size of dispersed
particles enabling better subsequent separation of the two
phases.
The drum 10 of Figure 1 is a horizontal, rotating
cylinder having rear 12 and front 13 ends, each partially
closed by a washer. The cylindrical side wall 11 is provided
with internal protrusions or ribs that encourage mixing
of the drum contents by the rotating drum. The drum is
supported on rollers 15 connected to a frame 16 and contains
a drive motor 17 and drive means 18. Hydrocarbon diluent and
steam, if desired, may be introduced into the interior of
the drum 10, illustrated in Figure 2 through a rotatable
distributor valve 19, which feeds to a series of perforated
pipes 20. These pipes 20 extend longitudinally along the
interior cylindrical surface 21 of the drum 10 in spaced
relationship about its circumference. The valve 19 feeds
the hydrocarbon diluent to the pipes 20 continuously or as
necessary. The mixture to be treated 23 is fed into the
rear end 12 of the drum by way of a pipe 24. A seal 25
-14-
98
prevents drum contents 22 from spilling out of the rear 12of the drum. Alternately, the mixture may be fed to the drum
10 through a flexible rotating hose that is attached to the
central part of the drum rear 12. The drum contains free
bodies 26 that tumble through the drum contents 22. Product
27 leaves the drum 10 through an opening 28 that is covered
with an apertured wall 29 such as a mesh screen, or a perfor-
ated plate to permit passage of prepared product but which
prevents passage of free bodies 26 from the drum 10.
If desired, the hydrocarbon diluent may be added to the
mixture $eed before it enters the drum or may be added to the
drum by other means.
The drum 10 may be rotated by the motor 17 and associ-
ated drive 18 at any rate of rotation that is most effective
for the mixture 23 to be treated from very slow up to but not
exceeding two times the critical rate. The critical rate of
rotation is reached when at the inside drum surface 21 the
centrifugal force exceeds the force of gravity. Critical
rotation is defined in revolutions per minute as:
Critical rotation rate a~ where r is the drum inner
radius in feet. Above this critical rate, some drum content
commences to attach itself to the drum wall and does not
readily mix with the remainder of the drum contents. At
rotation rates between one and two times the criticai rate,
progressively more of the drum content attaches itself to the
drum wall and does not take part in the tumbling process op-
erating in the drum 10. Rotating the drum 10 at more than
twice the critical rate is not the intent of the present
-15-
invention. The desired rate of drum 10 rotation varies wi-th
each type of feed 23 being treated and is influenced among
others by the viscosity of the mixture 22, the density dif-
ference between the mixture 22 and the free bodies Z6, the
solids content of the mixture 22 and the level of the drum
contents 22.
For many of the mixtures 22 treated the drum 10 will be
maintained more than half full, level 32, and for some mix-
tures 22 the drum 10 may be kept substantially filled to the
top, as long as the viscosity of the feed mixture 22, the
solids concentration and the density difference between the
components of the mixture 2~ and the free bodies 26 permit for
a continuous thorough mixing of the drum contents with said
free bodies 26.
The oil and water mixtures to which this invention is
directed are preferably those having a bitumen content of 30~0
by weight or above. The solids content should not exceed 60,o
by weight and preferably will be 15~o or lower with the re-
mainder of the mixture being aq~leous phase. It is believed
that the hydrocarbon d:iluent serves at least three basic
functions. One function is to reduce the viscosity of the
oil phase so that entrapped solids will be more easily trans-
ferred to the aqueous phase. Secondly, in high viscosity
bitumens, the diluent enhances the ability of oleophilic free
bodies to coalesce, agglomerate or otherwise increase the
size of the bitumen particles which would normally be too
viscous to temporarily adhere to the free bodies in order to
grow in size. Thirdly~ the diluent reduces the viscosity
of the bitumen or oil phase to a viscosity that would,
-16-
without the diluent, be attainable only at higher tempera-
tures. The lessening of viscosity at lower temperatures
takes advantage of the higher interfacial tension between
bitumen and water at such lower temperature in promoting
phase separation.
The hydrocarbon diluent that is used may be any hydro-
carbon which is miscible with the oil phase of the mixture
but not with the aqueous phase. Especially preferred is
that fraction obtained from the refining of crude petroleum
referred to as naphtha.
Without in any way attemptlng to limit the scope of
this invention, the following theory is offered as to how
particle size growth is accomplished. It is believed that
the oil phase particle size growth that takes place when a
mixture of continuous aqueous phase and dispersed oil phase
is tumbled in a drum containing a hydrocarbon diluent in the
presence of oleophilic free body surfaces may be explained
as a mechanism of oil film building and shedding. In this
mechanism, dispersed oil phase particles of the mixture in
the drum are reduced in viscosity and come in contact with
an oleophilic surface, adhere thereto, unite on -that surface
with other oil phase particles and form into a coat that
continues to grow in thickness until the forces of self ad-
hesion in the oil phase coat cannot resist the forces of
erosion on the coat surface caused by the movement of mix-
ture past this coat. At that instant the coat begins to
shed oil phase particles which, for the conditions of the
present invention on the average, are larger than the oil
phase particles originally present in the mixture fed to the
-17-
11~4~8 `
drum. The force of erosion varies with location in the drumcontents; and since the free bodies in the drum are mixing and
moving in the drum, therefore the force of erosion on the
oleophilic surface of a free body varies withtime thus per-
mitting a cyclic accumulation of oil phase on free bodies and
a cyclic shedding of accumulated oil phase therefrom. The
shed oil phase particles appear to have an optimum size with
a particular oil phase viscosity. Lowering the viscosity
beyond this point tends to lessen particle size from the
optimum. However, such particles may still be larger than
they were to begin with.
Similarly, free bodies with hydrophilic surfaces may be
used to collect water phase on their surfaces and to provide
for an increase of particle size of aqueous phase in a mix-
ture with continuous oil phase. A combination of oleophilic
and hydrophilic free bodies may be used to advantage in cases
where it is desirable to remove particles of continuous phase
out of dispersed phase particles that are being increased in
size. Thus free bodies with hydrophilic surfaces may be added
to the free bodies with oleophilic surfaces in the drum to
treat a mixture containing continuous aqueous phase. Con-
versely, free bodies with oleophilic surfaces may be added to
the free bodies with hydrophilic surfaces in the drum to treat
a mixture containing continuous oil phase.
Free bodies may be in the form of spheres, spheroids,
pebbles, teardrops, rods, discs, saddles, snowflakes or of
any other shape, simple or complex, which is effectiYe in
searching out dispersed phase particles in the mixture. The
free bodies may be solid, hollow, or apertured. They may also
-18-
be smooth but are preferably of` a rough or of a porous surface.The size of the free bodies used in said drum depends to a
large degree upon the consistency of the mixture in -the drum
that is to be treated. The mean dimension of these free bodies
preferably is within the range 0.1 to 10.0 inches and most
preferably within the range 0.5 to 2.0 inches. However, free
bodies larger than 10 inches and smaller than 0.1 inch can be
used without departing from the scope of the present invention.
The free bodies may also be conflgured to contain both
oleophilic and hydrophilic surfaces. Examples of such bodies
are disclosed in copending application, Serial No. 333,832.
The desired density of the free bodies varies with the
shape and size of the bodies used, the viscosity of the oil
phase, the amount of hydrocarbon diluent, the solids content
of the mixture and the level of the contents maintained in
the drum. It is preferably within the range 60 to 600 pounds
per cubic foot and most preferably within the range 100 to
300 pounds per cubic foot.
Free bodies may be cast, molded, formed or fabricated
in other ways. Oleophilic free bodies may be made with oleo-
philic materials or they may be made from o-ther materials and
then covered with a coating of a strongly oleophilic material
that is abrasion resistant, resistant to oil phase of the
mixture under treatment and that may be made to adhere strongly
to the body. Suitable oleophilic ma-terials -that may be used
in the fabrication of oleophilic free bodies are neoprene,
urethane, polypropylene, plastics and artificial rubbers.
Hydrophilic free bodies may be made using ceramics, glass,
--19--
carbides or other strongly hydrophilic materials~ Pebbles
or flint may be used as well.
The desired viscosity of the phases of the mixture
depends upon which is the continuous phase. ~Yhen oil is the
continuous phase of the mi~ture, s~lfficien-t hydrocarbon
diluent is added to maintain viscosity of the oil phase
such that the free bodies are permitted to freely travel
through the mixture. Preferably the viscosity will be with-
in the range 0.01 to 500 poises, with the most preferred
range being 0.1 to 50 poises. When oil is the dispersed
phase of the mixture, the preferred viscosity of the oil
phase is such as to provide optimum "-tackiness" to the oil
phase particles and still allow removal of solids to the
aq-ueous phase. Generally, "tackiness" refers to the ability
of oil particles to adhere to themselves and to oleophilic
surfaces as described above and will also be in the range
of 0.01 to 500 poises.
While particle size enlargement may be achieved in
small rotating horizontal drums, effec-tiveness of the present
invention may be enhanced by the use of large diameter drums
since these, for a given mi~ing action, may rotate at a
slower rate. Such a slower rate of rotation in larger drum
sizes may provide for longer accumula-tion and shedding
cycles of dispersed phase on and from free body surfaces and
in many cases provides for improved performance of the present
invention. The preferred drum diameter is wi-thin the range
7 to 70 feet,and the preferred drum length i5 within the range
10 to 200 feet.
-20-
li~4~98
\
Reagents other than hydrocarbon diluents may be added
to the mixture before it enters the drum or while it is in
the drum for the purpose of aiding in the process of the
present invention, for breaking emulsions, for increasing
the affinity of the dispersed phase for the surfaces of the
free bodies, for increasing the affinity of the surfaces of
the free bodies for the dispersed phase and/or for increas-
ing the affinity of particulate solids in the mixture for
one of the phases of the mixture. Addition of inorganic
alkaline earth hydroxides or salts, such as for example
calcium sulphate or calcium hydroxide is very effective for
breaking tight oil sand oil-in-water emulsions and for rapid
accumulation of bitumen coatings on the free bodies in the
mixture. Non-ionlc water soluble-polyethylene oxide polymers
having a molecular weight in the range of 10,000 to 7,000,000
added to the mixture may serve to aid the alkaline earth
chemicals in breaking tight oil-in-water emulsions. Suitable
temperature for adding such polymers to the mixture is when
the mixture is in the range of 120 to 210 F. Depending
upon the desired temperature for uniting of dispersed oil
phase particles, this polymer addition may be made to the
drum contents or it may be made to the feed prior to entering
the drum. In this latter case, the feea may be cooled prior
to entering the drum for the purpose of operating both the
chemical treatment step and the dispersed particle size growth
step at differing optimum temperatures. United States
Patent No. 4,058,453 issued on November 15, 1977 to Mahendra
S. Patel, et. al., discloses the use of such a polymer mixture
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11~4~98
to break an oil-in-water emulsion. However, instead of using
free bodies and a hydrocarbon diluent to enlarge the size of
dispersed phase particles as disclosed in the present inven-
tion, Patel, et. al., disclose the need for a hydrocarbon
solvent to collect the dispersed phase. This is to be dis-
tinguished from the present inventionwhere the hydrocarbon is
used to reduce viscosity and not as a collecting solvent.
Non-ionic surface active compounds, as for example a
chemical demulsifier comprising polyethoxyalkene compound,
sold under the trade name of NALCO D-1645 produced by the
Nalco Chemical Company, may be added to the feed or to the
drum for the purpose of breaking a water-in-oil emulsion and
for making it easier for the free bodies to enlarge dispersed
water phase particles.
Another demulsifier for adding to a water-in-oil
emulsion in the present invention is sold under the trade
name of BREAXIT 7941 and comprises a mixture of: (1) One
part of the reaction product of diethyl ethanolamine with
premixed propylene oxide and ethylene oxide; and (2) approxi-
mately three parts of a palmitic acid ester of the reaction
product of an alkyl phenol formaldehyde resin with ethylene
oxide. Other ~emulsifiers that may aid free bodies in
increasing the mean water particle size of a water-in-oil
emulsion in the present invention are polyoxypropylene
glycols produced by the Wyandotte Chemical Company under the
tradename "Pluronic".
An enhanced transfer of particulate solids to the water
phase of the mixture tumbling with free bodies in the drum of
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S~3~'
~he present invention may, in some mix-tures, be ef~ected by
addition to these mix-tures of hydropllilic surface active
transfer agents, such as polyphosphates. Any water soluble
salt of pyrophosphoric acid, H2P207, such as for example tetra
sodium pyrophosphate or sodium tripolyphosphate, are transfer
agents and may be mixed with the feed or the drum contents in
proportion of 0.01 percent to 1.~ percent ~o effect an im-
provement in the recovery of particulate solids in the water
phase. Addition of sodium hydroxide with said polyphosphate
reagent in about equal proportion may aid in effesting the
improvement.
In instances where the oil phase of the mixture may con-
tain heavy mineral, for example, bitumen may contain as high
as 1 to 10 percent of heavy minerals as for example zircon,
rutile, ilmenite, tourmaline, apatite, staurolite, garnet,
etc. It may be desirable to employ chelating agents to make
these particulate heavy minerals water wet and cause them to
report to the water phase. ~xamples of suitable chelating
agents are ethylenediamine tetraacetic acid, naturally
occurring amino acids, sodium gluconate, gluconic acid, sodium
oxalate and diethylene glycol. Chelating agents may be added
to mixtures wherein oil is the continuous phase or they may
be added to mixtures where water is the continuous phase.
Generally they are the most effective when added to mixtures
in which oil is the continuous phase.
The following example is illustrative of the present
invention but is not to be considered a limitation thereof.
For instance, the examples disclosed in copending applica-
tion, Serial No. 333,832 filed August ~5, 1979 could readily
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be modified by the adclition of a hydrocarbon diluent.
E~A~IPLE
A primary froth product from a hot water oil sandsextraction plant conta~ning 42 percent bitumen, 1~ percent
solids and 46 percent water is treated in a horizontal ro-
tating drum as shown in Figure 1. Lengthwise baffels on the
interior cylindrical wall of the drum cause mixing of the
drum contents and prevent -the cylinder wall from sliding past
the drum contents. The contents of the drum are maintained
at a -temperature of 100 F. The 6.0 feet diameter 6.0 feet long
drum is filled to one-half full with 0.75 inch flint pebbles
and 0.75 inch spheres molded from a mixture of litharge and
neoprene to give spheres a density of 150 pounds per cubic
foot. There are about an equal number of pebbles and spheres
in the drum that rotates at 10 rpm. Six ~ons per hour of
froth, containing 35 volume percent air are fed continuously
to the drum that i.s kept filled. Six tons of hydrocarbon
diluent naphtha ls fed to the dr-um through the same feed pipe
and mixes with -the froth in the drum. Air bubbles of the
froth feed collapse in the drvm because of -the tumbling and
stirring action of the free bodies in conjunction with the
dilution of the froth by naphtha. The product that leaves
the drum through the mesh covered exit consists of a stream of
water and oil that readily separate in-to a top layer of oil
phase and a bottom layer of aqueous phase when put into a
~essel. The aqueous phase contains water wet solids and the
oil phase contains less than 10 percent water and less than 5
percent solids.
98`
Although the invention as has been described is deemed
to be that which forms the preferred embodiments thereof, it
is recognized that departures may be made therefrom and still
be within the scope oP the invention which is not to be
limited to the details disclosed but is to be accorded the
full scope of the claims so as to include any and all equiva-
lent methods and apparatus. For example, the drum may be
-inclined instead of being perfectly horizontal without depart-
ing from the scope of the invention. ~Other similar modifica-
tions will also become apparent to those skilled in the art.
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