AN EMULSION FORMATION SYSTEM AND MIXING DEVICE

SYSTEME POUR LA FORMATION D'EMULSIONS ET DISPOSITIF MELANGEUR

English Abstract

A method for preparing oil in water HIPR emulsions
includes the steps of providing a Newtonian liquid
including a mixture of a viscous hydrocarbon, an
emulsifying additive and water; subjecting the
Newtonian liquid to a first shear force whereby a
substantial portion of the Newtonian liquid is radially
displaced and mixed so as to form a non-Newtonian
liquid; thereafter subjecting remaining non-radially
displaced Newtonian liquid to a second shear force to
mix the remaining non-radially displaced Newtonian
liquid into the non-Newtonian liquid to form the HIPR
emulsion, which emulsion is a stable oil in water
emulsion having a droplet size of between about 1 to 30
microns and having a droplet size distribution (x) no
greater than about 1, the droplet size distribution
being defined as follows:
<IMG>
D90 is a droplet size wherein about 90% by volume
of all droplets in said emulsion are equal to or below;
D10 is a droplet size wherein about 10% by volume
of all droplet, in said emulsion are equal to or below;
and
D50 is a droplet size wherein about 50% by volume
of all droplet, in said emulsion are equal to or below.

Claims

The embodiments of the invention in which an exclusive
property or privilege is claimed are defined as follows:-
1. A method for forming an oil in water HIPR
emulsion, comprising the steps of:
forming a Newtonian liquid comprising a mixture of
a viscous hydrocarbon, an emulsifying additive and
water;
subjecting said Newtonian liquid to a first shear
force wherein a substantial portion of said Newtonian
liquid is radially displaced and mixed so as to form a
non-Newtonian liquid;
thereafter subjecting remaining non-radially
displaced Newtonian liquid to a second shear force to
mix said remaining non-radially displaced Newtonian
liquid into said non-Newtonian liquid to form said HIPR
emulsion comprising a stable oil in water emulsion
having a droplet size of between about 1 to 30 microns
and having a droplet. size distribution (x) no greater
than about 1, said droplet size distribution being
defined as follows:
<IMG> wherein
D90 is a droplet size wherein about 90% by volume
of all droplets in said emulsion are equal to or below;
23

D10 is a droplet size wherein about 10% by volume of all droplets in said
emulsion are equal to or below; and
D50 is a droplet size wherein about 50% by volume of all droplets in said
emulsion are equal to or below.
2. A method according to claim 1, further including the step of
subjecting said substantial portion of said Newtonian liquid to said second
shear
force so as to prevent rigid flow of said substantial portion.
3. A method according to claim 1 or 2, wherein said steps of subjecting
to a first shear force and a second shear force are carried out in a cylinder
having a
volume selected so as to provide a residence time for said Newtonian liquid in
said
cylinder of between about 1 to 5 minutes.
4. A method according to claim 1, 2 or 3, further including the steps of:
selecting a cylinder having an inlet for said Newtonian liquid and an
outlet for said HIPR emulsion, and having a length (L) and diameter (D), said
first
and second shear means each having a diameter (d);
positioning said first shear means at a distance from said inlet or
about 1/3L;
positioning said second shear means at a distance from said first
shear means of about 1.5d;
providing a ratio of cylinder length to cylinder diameter (L/D) of
between about 1.5 to 3.0; and
providing a ratio of shear means diameter to cylinder diameter (d/D)
of between about 0.35 to 0.45.
5. A method according to claim 1, 2, 3 or 4, wherein said step of
forming said Newtonian liquid includes the step of mixing said viscous
hydrocarbon and said water at a ratio by volume of viscous hydrocarbon to
water
of between about 80:20 to 95:5.
6. A method according to claim 5, wherein said step of forming said
Newtonian liquid further includes the step of providing a viscous hydrocarbon
having an API gravity of between about 5 to 15 at 60°F.
24

7. A method according to claim 6, wherein said step of forming said
Newtonian liquid further comprises adding said emulsifying additive to said
water
at a concentration of no greater than about 3000 ppm.
8. A method according to claim 7, wherein said step of adding said
emulsifying additive further includes the step of selecting said emulsifying
addictive from a group consisting of cationic, anionic and non-ionic
emulsifiers.
9. A method according to claim 7, wherein said step of adding said
emulsifying additive comprises the step of adding a nonylphenol ethoxylate
surfactant to said water at a concentration of no greater than about 3000 ppm.
10. An apparatus for forming an oil in water emulsion from a Newtonian
liquid comprising a mixture of a viscous hydrocarbon, an emulsifying additive
and
water, the apparatus comprising a plurality of means for subjecting said
Newtonian liquid to shear force positioned serially along a flow path of said
Newtonian liquid, said plurality of shear means comprising at least a first
shear
means and a second shear means arranged serially, so that a substantial
portion of
said Newtonian liquid is subjected to a first shear force and radially
displaced
from said first shear means and mixed so as to form a non-Newtonian liquid,
and
remaining non-radially displaced Newtonian liquid is subjected to a second
shear
force and mixed into said non-Newtonian liquid to form an HIPR emulsion
comprising a stable oil in water emulsion having a droplet size of about 1 to
30
microns and having a droplet size distribution (x) no greater than about 1,
said
droplet size distribution being defined as follows:
<IMG>
wherein
D90 is a droplet size wherein about 90% by volume of all droplets in
said emulsion are equal to or below;
D 10 is a droplet size wherein about 10% by volume of all droplets in
said emulsion are equal to or below; and
D50 is a droplet size wherein about 50% by volume of all droplets in
said emulsion are equal to or below.
25

11. An apparatus according to claim 10, further comprising a cylinder
having an inlet for said Newtonian liquid and an outlet for said HIPR
emulsion,
said plurality of shear means being positioned serially within said cylinder
along a
flow path of said Newtonian liquid, and an outlet for said HIPR emulsion, said
plurality of shear means each having a diameter (d) and said cylinder having a
length (L) and a diameter (D), said first shear means being positioned at a
distance
from said inlet of about 1/3L, said second shear means being positioned at a
distance from said first shear means of about 1.Sd, and a ratio of cylinder
length to
cylinder diameter (L/D) being between about 1.5 to 3.0, and a ratio of shear
means
diameter to cylinder diameter (d1D) being between about 0.35 and 0.45.
12. An apparatus according to claim 11, wherein said cylinder is defined
about a central axis, said first shear means and a second shear means being
arranged serially for rotation about said central axis, said plurality of
shear means
being positioned serially within said cylinder along said flow path of said
Newtonian liquid.
13. An apparatus according to claim 11 or 12, wherein said cylinder has
a volume selected to provide, in conjunction with a flow rate of said mixture,
a
residence time for said mixture in said cylinder of between about 1 to 5
minutes.
14. An apparatus according to claim 11, 12 or 13, wherein said plurality
of shear means comprises a plurality of blades rotatably positioned serially
along
said flow path of said mixture.
15. An apparatus according to claim 14, wherein said inlet is positioned
substantially concentric with an axis of rotation of said plurality of blades.
16. An apparatus according to claim 11, 12, 13, 14 or 15, wherein said
cylinder is positioned substantially vertically and said inlet is disposed in
a bottom
end of said cylinder.
17. An apparatus according to any one of claims 10 to 16, further
comprising means for forming said mixture of a viscous hydrocarbon,
emulsifying
additive and water.
26

18. An apparatus according to claim 17, wherein said means for forming
said mixture comprises means for mixing said viscous hydrocarbon and said
water
at a ratio by volume of hydrocarbon to water of between about 80:20 to 95:5.
19. An oil in water HIPR emulsion, comprising:
an internal viscous hydrocarbon phase having an API gravity at 60°F
of between about 5 to 15;
an external water phase, a ratio by volume of said internal phase to
said external phase being between about 80:20 to 95:5; and
an emulsifying additive in a concentration of no greater than about
3000 ppm; said emulsion being characterized by a droplet size of between about
1
to 30 microns and a droplet size distribution (x) of no greater than about
one, said
droplet size distribution being defined as follows:
<IMG>
wherein:
D90 is a droplet size wherein about 90% by volume of all droplets in
said emulsion are equal to or below;
D 10 is a droplet size wherein about 10% by volume of all droplets in
said emulsion are equal to or below; and
D50 is a droplet size wherein about 50% by volume of all droplets in
said emulsion are equal to or below.
20. An emulsion according to claim 19, wherein said emulsion is formed
from a continuous process.
21. An emulsion according to claim 19 or 20, wherein said droplet size
is no greater than about 7.0 microns.
22. An emulsion according to claim 19, 20 or 21, wherein said droplet
size is no greater than about 4.0 microns.
27

Description

214 5 0 3 0 92-172
BACKGROUND OF THE INVENTION
The invention relates to the field of emulsions
and, more par'ticula:rly, to a method and apparatus for
continuous preparation of high internal phase ratio
emulsions characterized by small droplet~size and
narrow droplei~ size distribution.
In the pearoleum industry, problems frequently
arise regarding the transportation of crude oils which
are viscous when produced and which, therefore, do not
flow easily.
Numerous proposals have been made for transporting
such viscous crude oils. These include such
alternatives as hearing the crude oil, adding solvents
or lighter crude oils, forming an annulus of water
around the crude oil, or forming emulsions of the crude
oil in water.
The present in~rention relates to a method and
apparatus for forming emulsions of the crude oil in
water to obtain an emulsion which flows easily for
conventional transportation. Obviously, such
transportation is mare efficient when the emulsion
formed has a high ratio of internal phase crude oil or
hydrocarbon as compared to the external phase of water.
Such emulsions are known as High Internal Phase Ratio
(HIPR) emulsions and are the further subject of the
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time.
Further, when it is desired to prepare an emulsion
having relatively small droplet size, conventional
pumps must be operated at a shear rate which can cause
phase inversion to occur. Such high shear rates
consume large amounts of power and require prohibitive
amounts of emulsifiers to prevent phase inversion.
Accordingly, it is a principal object of the
present invention to provide a system for forming an
l0 HIPR oil in water emulsion having a droplet size of
between about 1 to 30 microns and having a narrow
droplet size distribution.
It is another object of the present invention to
form such an emulsion without prohibitive amounts of
mixing energy or emulsifiers, and without causing phase
inversions.
It is still another object of the present
invention to provide such a system which can be used to
prepare emulsions having a droplet size of the internal
2o phase less than 7 microns.
Other objects and advantages will become apparent
to those skilled in the art after a consideration of
the following disclosure.
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time. v
Further, when it is desired to prepare an emulsion
having relatively small droplet size, conventional
pumps must be operated at a shear rate which can cause
phase inversi~~n to occur. Such high shear rates
consume large amounts of power and require prohibitive
amounts of emulsifiers to prevent phase inversion.
Accordin~~ly, it is a principal object of the
present inveni~ion to provide a system for forming an
HIPR oil in w<~ter emulsion having a droplet size of
between about 1 to 30 microns and having a narrow
droplet size.
It is another object of the present invention to
form such an emulsion without prohibitive amounts of
mixing energy or emulsifiers, and without causing phase
inversions.
It is still another object of the present
invention to provi.dE=_ such a system which can be used to
prepare emulsions having a droplet size of the internal
phase less then 7 microns.
Other objects and advantages will become apparent
to those skilled in the art after a consideration of
the following disclosure.
4

214 5 0 3 0 92-172
SUMMARY OF THE INVENTION
The foregoing objects and advantages are obtained
by a method for forming an oil in water emulsion which
comprises, acc:ording to the invention, the steps of
forming a Newtonian liquid comprising a mixture of a
viscous hydrocarbon, an emulsifying additive and water;
subjecting said Newtonian liquid to a first shear force
wherein a substantial portion of said Newtonian liquid
is radially displaced and mixed so as to form a non-
Newtonian liquid; thereafter subjecting remaining non-
radially displaced Newtonian liquid to a second shear
force to mix said remaining non-radially displaced
Newtonian liquid into said non-Newtonian liquid to form
said HIPR emulsion comprising a stable oil in water
emulsion having a droplet size of between about 1 to 30
microns and having a droplet size distribution (x) no
greater than about 1, said droplet size distribution
being defined as follows:
x -- D90 - D10, wherein:
D50
D90 is a droplet size wherein about 90% by volume
of all droplets in said emulsion are equal to or below;
D10 is a droplet size wherein about 10% by volume
of all droplets in said emulsion are equal to or below;
and
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214 5 0 3 0 92-172
D50 is a droplet size wherein about 50o by volume
of all droplets in said emulsion are equal to or below.
Accordiri~g to the invention, the liquid is
preferably subjected to said shear forces in.a cylinder
selected to provide a residence time of between about 1
to 5 minutes and having an inlet for said Newtonian
liquid, an outlet for said HIPR emulsion, and a
plurality of means for providing shear force to said
mixture, said plurality of shear means each having a
diameter (d) <ind said cylinder having a length (L) and
diameter (D). According to the invention, a first
shear means oi: said plurality of shear means is
positioned at a distance from said inlet of about 1/3L;
a second shear means of said plurality of shear means
is positioned at a distance from said first shear means
of about 1.5d; a ratio of cylinder length to cylinder
diameter (L/D) is sealected between about 1.5 to 3.0; a
ratio of shear means diameter to cylinder diameter
(d/D) is selecaed bEaween about 0.35 to 0.45.
BRIEF DESCRIPTION OF THE DRAWINGS
A detailed description of the preferred
embodiments of the invention follows, with reference to
the accompanying drawings, in which:
Fig. 1 is a schematic view of a prior art system
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214 5 0 3 0 92-172
for preparing an emulsion;
Fig. 2 is a schematic view of a mixing cylinder,
according to the invention; and
Fig. 3 is a graph illustrating a typical droplet
size distribution.
DETAILED DESCRIPTION
The invention :relates to a method and apparatus
for continuou:~ preparation of high internal phase ratio
(HIPR) emulsions characterized by small droplet size
and narrow droplet aize distribution.
Referring to the drawings, a detailed description
of the preferred embodiments of the invention will be
given.
Fig. 1 i7Llust.rates a typical system for preparing
HIPR emulsions according to the prior art, which
includes a mi~;ing device l0, a static mixer 12, a
conduit 14 for an internal viscous hydrocarbon phase
and a conduit 16 for an external water phase and
emulsifying additive. The conduits 14, 16 join and
introduce the internal and external phase to static
mixer 12, where the phases are mixed to form a mixture
or dispersion which flows to mixing device 10 where the
emulsion is farmed and is passed on to subsequent
processing or storage through outlet 18.
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Prior art mixing device 10 is typically a
conventional ~~ump which provides a shear force to the
dispersion su:Eficient to form an emulsion of the
internal phases in the external phase. Conventional
mixing device: l0 typically have a single rotating
mixing member or blade, and are sized to provide a
residence times for incoming fluids of about to seconds.
As described above, such devices require high energy
and large amounts o:E emulsifying additive to form HIPR
l0 emulsions with small droplet diameters, and frequently
cause an inversion of the phases when too much shear is
applied. Large amounts of shear are required in
conventional mixing devices, however, to obtain HIPR
emulsions with drop:Let diameters less than 7.0 microns.
Thus, phase inversions frequently result before the
desired droplsa size is obtained by such conventional
mixing device;.
Also as described above, conventional mixing
devices do not. apply a substantially uniform shear
force to the fluids, resulting in wide droplet size
distributions which adversely effect the flow
characteristics of t:he emulsion so formed.
Fig. 2 illustrates a mixing device 20 according to
the invention. Mixing device 20 may preferably be
disposed in a system such as that of Fig. 1, replacing
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conventional mixing device 10. Mixing device 20,
according to 'the invention, comprises a cylinder 22
having an inlet 24 and an outlet 26 and a plurality of
means 28 for providing shear force which shear means 28
are serially positioned in cylinder 22 along a flow
path of the m:ixtura.
Cylinder 22 is preferably oriented substantially
vertically, with inlet 24 being located in a bottom
surface 30 thereof, and with outlet 26 being located in
a top surface 32.
Shear means 28 preferably comprise a plurality of
blades 34, 36 serially disposed rotatably, for example
on a shaft 38, along a longitudinal axis of cylinder
22. Shear means 28 may alternatively be any structure
known in the art t.o apply shear to flowing fluids, such
as vanes, turbines, spiral flow passages, and the like.
Inlet 24 is prE_ferably aligned substantially
concentric with th.e longitudinal axis or shaft 38 of
cylinder 22. This alignment helps to direct the
mixture to blade 34 in the most effective manner.
Rotation can be imparted to blades 34, 36 through
any type of motive means 40 known in the art
(schematically depicaed in Fig. 2). Motive means 40
preferably im~~arts rotation to blades 34, 36 so as to
subject the mixture being emulsified to shear forces
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corresponding to a power input of between about 0.1 x
106 to 1. 0 x 10' Watt: ~ s/m3, so as to form an emulsion
having the desired droplet size and droplet size
distribution characteristics. The power input varies
within the foregoing range as a function of the
capacity of the mi:xi.ng device, that is, the greater the
capacity of the mixing device, the greater the power
input required to obtain the desired droplet size arid
distribution.
Cylinder 22 has a geometry which cooperates with
size and positioning of shear means 28, according to
the invention, to provide thorough mixing of the
mixture within cylinder 22, despite changes in
thixotropic or rheological properties of the phases to
be emulsified. The process begins with a mixture of
water, hydrocarbon and emulsifier that is substantially
a Newtonian li~xuid. By Newtonian Liquid is meant a
liquid which flows substantially immediately on
application of force and for which the rate of flow is
directly proportional to the force applied. As the
emulsion is formed, the mixture takes on the
characteristic: of a viscoelastic or non-Newtonian
fluid, that is, its 'viscosity is dependent upon the
rate of shear. These changes in properties occur as
the emulsion is formed and the incoming Newtonian

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mixture is transformed into a non-Newtonian emulsion.
The cylinder geometry and shear means arrangement
allows the preparation of HIPR emulsions having
substantially uniform internal phase droplet sizes in a
range of about: 1 to 30 microns, and preferably less
than about 7.0 microns. Still referring to Fig. 2, the
cylinder geomeary and shear means arrangements of the
present invention will be illustrated.
According' to the invention, shear means 28 are
positioned serially along the flow path of the
Newtonian liquid min;ture. This serial positioning is
illustrated in Fig. 2 as the serial positioning of
blades 34, 36. In operation, first blade 34 radially
displaces a substa:nt:ial portion of incoming Newtonian
liquid mixture against the walls of cylinder 22.
Preferably, about 30% of the total flow is thus
displaced. This portion strikes the walls of cylinder
22 resulting in a minimum pressure at the cylinder wall
and a maximum pressure at the tip of blade 34. This
results in a further circulation of the liquid being
mixed.
As the ra~~ially displaced portion of the Newtonian
liquid mixture is subjected to shear force and mixed by
blade 34, the ~~hases begin to emulsify resulting in a
change in properties of the liquid to a non-Newtonian
11

214 5 0 3 0 92-172
liquid. This non-Newtonian liquid no longer reacts
immediately to forces and tends to rigidly rotate about
shaft 38.
The remaining non-radially displaced Newtonian
liquid, which is not radially displaced by blade 34,
flows or climbs up shaft 38, particularly in light of
the rigid flow of the mixed non-Newtonian portion.
This flow of 'the remaining portion of Newtonian liquid,
up rod or sha:Et 38, is referred to as "rod climbing"
flow.
This rem<~ining portion, if not further subjected
to shear forcEas, would not be mixed as thoroughly as
the substantial partion mixed by blade 34. Further,
rod climbing j:low reduces the overall effectiveness of
the mixing. ~L'he emulsion so formed would, therefore,
have unacceptable droplet size and droplet size
distribution characteristics, which could only be
improved by increasing the shear rate, thus requiring
more emulsifier and increasing the risk of phase
inversion.
Thus, according to the invention, blade 36
subjects the remaining non-radially displaced portion
of Newtonian liquid to an additional shear force to mix
the remaining portion into the non-Newtonian liquid.
Rod climbing flow is thus eliminated and an emulsion
12

CA 02145030 2003-10-02
9a~i~z
having desired characteristics is formed without
excessive emulsifier or increased risk of phase
inversion. Blade 36 also !anther mixes the rigidly
rotating non-Newtonian Substantial portion ao as to
3 eliminate rigid flow and further increase mixing
effectiveness.
With further reference to Fig. a, the preferred
oylindar geometry ie expressed in terms of suitable
ratios of shear means 28 or blade 34, 36 diameter (d),
cylinder length (L) and cylinder diamster (D).
Cylinder ZZ preferably has a length and diameter
selected to provide a ratio of length to diameter (L/D)
of between about i.5 to 3Ø
Blades 34, 3s are preferably positioned within
cylinder Z2 at predetermined distances from inlet 24.
First blade 34 is disposed at a di9tance from inlet z4
of about one third of the length of cylinder Zz (L/3).
Second blade 36 is disposed at a distance from first
blade 34 of about 1.5 times the blade diameter (i.sd).
z0 A ratio of blade diamator to cylinder diameter (d/D) is
preferably between about 0.35 to 0.45, and is
preferably about o.4.
The afosesaid geometry of cylinder z2 induces a
flow~pattern in cylinder 2z which is not adversely
Z5 affected by changes in the theological or thixotropic
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properties of the fluid phases being emulsified.
Stagnation of flow .in cylinder 22 is avoided, as are
rod climbing~f'low and rigid rotation, thus preventing
application of non-uniform shear forces to the mixture
and preventing the formation of bimodal emulsions, or
emulsions having non-uniform droplet sizes.
The cylinder volume is preferably selected, in
conjunction with the expected flow rate of mixture, to
provide a residence time for the fluids in the cylinder
of between about 1 i~o 5 minutes.
This increased residence time, as compared to that
of the prior a.rt, allows the emulsifying additive to
adequately disperse the internal phase and stabilize
internal phase: droplet size without the previously
required large. amounts of shear force.
The internal viscous hydrocarbon phase and
external water phase may preferably be supplied to
mixing device 28 through any flow conducting means
known in the art such as, for example, conduits 14, 16
as shown in Fig. 1.
The emulsifying additive may preferably be an
anionic, cationic or non-ionic surfactant, and more
preferably is a nonylphenol ethoxylated surfactant. An
example of a suitable emulsifying additive is a
composition of 97% by weight of an alkyl phenol
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ethoxylate bared surfactant compound (such as INTAN-
100'~"~ by INTEVEP, S.A.) and 3o by weight of a phenol
formaldehyde eathoxy:late resin having about 5 units of
ethylene oxide.
The emulsifying additive is preferably added to
external water. phase at a concentration, to viscous
hydrocarbon content,, of no greater than about 3000ppm.
The systs~m, according to the invention, operates
as follows. The ini=ernal viscous hydrocarbon phase and
the external grater phase and emulsifying additive are
supplied by rsapective conduits, such as conduits 14,
16 of Fig. 1, where a mixture of the phases is formed,
preferably in mixing means 12.
Referring to Fig. 2, the mixture then passes to
inlet 24 of mixing device 20. The flow of mixture
enters cylinder 22 where a substantial portion,
preferably at least approximately 80% of the flow, is
radially displaced by first blade 34 against the walls
of cylinder 22. A static head is provided by the
cylinder geometry which promotes recirculation of the
fluid and prevents t:he formation of regions of uneven
stress or shear forces, thereby helping to provide a
narrow droplet size distribution. The mixing induced
by first blade 34 serves to create a non-Newtonian
liquid having viscoe:lastic properties. This results in

214 5 0 3 0 92-172
the liquid rotating around shaft 38 in rigid motion,
and causes the remaining portion of Newtonian liquid to
flow up shaft 38 in a rod climbing type flow of the
liquid.
Second blade 36 serves to eliminate such rod
climbing flow by mixing the remaining portion into the
mixed non-Newtonian portion and eliminates the rigid
flow or rotation of the substantial portion, thus
providing imp~~oved :mixing and an emulsion having the
desired chara<~teristics, particularly when a droplet
size of 7.0 m:LCrons or less is desired.
Second b:Lade 36 thus helps to reduce non-
uniformity of droplet size and to provide a narrow
droplet size distribution (x), defined as (D90 -
D10)/D50, whi<:h is no greater than about 1, wherein:
D90 is a dropla_t size wherein about 90% by volume
of all dropleta in aaid emulsion are equal to or below;
D10 is a droplet size wherein about 10% by volume
of all dropleta in aaid emulsion are equal to or below;
and and
D50 is a dropl<~t size wherein about 50% by volume
of all dropleta in ;said emulsion are equal to or below.
Referring to Fig. 3, an illustration is given to
further define the aforesaid droplet size distribution.
The y-axis red>resent=s the entire droplet family,
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ordered by inc:reasing droplet diameter. Thus, D10
corresponds to the droplet diameter of the droplet at
the tenth perr:enti.le along the y-axis. D50 and D90
correspond in the same fashion to the 50th and 90th
percentile, respectively. The x-axis represents the
droplet size i.n microns. As Fig. 3 is merely
illustrative of the general meaning of the droplet size
distribution factor,, actual droplet size values are not
included on the x-axis. Thus, the droplet size
distribution factor as described above is reflective of
the uniformity of droplet size contained in the
emulsion. A small distribution factor indicates a
narrow droplet. size distribution and a substantially
uniform droplet size.
Several examples follow which compare conventional
systems to that of t:he present invention. The examples
were based on the preparation of hydrocarbon-in-water
emulsion. The hydrocarbon used was natural Cerro Negro
bitumen from the Orinoco Belt in Venezuela and had an
API gravity of 8.4 degrees at 60°F as well as chemical
properties as shown below in Table I.
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Table I
BITUMEN CNR
Gravity API ( Ei 0 ) 8 . 4
Saturated % (TLC/FID) 11.8
Aromatic % (ThC/FID) 45.8
Resins %(TLC/FID) 30.9
Asphaltenes % (TLC/:FID) 11.5
Acidity, mgKOH/g (ASTM D-664) 3.07
Basic nitrogen mg/Kg (SHELL-1468) 1,546.1
Total nitrogen mg/Kg (ASTM D-3228) 5,561
Sulphur % 3.91
Nickel (mg/1) 105.9
Vanadium (mg/7_) 544.2
The surfactant used was a composition consisting
of 97% (weight:) of <~n alkyl of a phenol ethoxylate-
based surfactant compound identified as INTAN-100T'"
supplied by IrfTEVEP,, S.A., and 3% (weight) of a phenol
formaldehyde e;thoxylate resin having about 5 units of
ethylene oxide:.
The objecaive._Ln each example was to obtain an
average droplea size of 4 microns or less with a ratio
of internal phase to external phase of at least 85:15
and a droplet size distribution factor of 1 or less.
EXAMPLE 1
Viscous hydrocarbon as described above was mixed
with water and emul:~ifying additive in a preliminary
static mixer.
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The mixture provided by the static mixer was then
fed to a conventional dynamic mixer (trademark: TKK,
model: PHM, m.anufacaurer: Tokushu Kika Kogyo LTD.,
Osaka, Japan) at a Blow rate providing a residence time
of 10 seconds.
With this conventional configuration, at a ratio
of internal phase to external phase of 85:15, the
smallest droplet size obtained was 8-10 microns. Even
with increased tem;pe:rature and emulsifying additive
concentration and reduced ratios of internal phase to
external phase, phase inversion occurred before the
target droplet size was reached.
EXAMPLE 2
In this example:, a premixing tank was substituted
for the static mixer of Example 1 to provide a
substantially homogeneous preliminary dispersion to the
conventional dynamic mixer, as in aforedescribed U.S.
Patent No. 4,018,426. The phases were mixed in the
premixing tank for about 30 minutes before passing
through the conventional mixer with a residence time of
10 seconds. At an internal phase external phase ratio
of 85:15, a droplet size of less than 4 microns was
achieved only when emulsifying additive was added in a
concentration, to viscous hydrocarbon content, of 6000
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ppm and significant amounts of energy were supplied.
The results of these tests are summarized below in
Table II.
TABLE II
TEST SURFACTANT P/Q DROPLET DIAMETER
(ppm) (Watt~s/m3) (microns)
1 2000 1.0 x 10g 8.5
2 4000 1.0 x 108 5.6
3 6000 1.0 x 10g 5.0
4 6000 1.5 x 10g 3.5
5 8000 1.0 x 108 3.0
Internal phase./extennal phase ratio: 85:15
Temperature: 66C
EXAMPLE 3
Emulsions were formed in a system as in Example 1,
but substituting an apparatus according to the
invention for the conventional dynamic mixer. The
mixer utilized. in accord with the present invention had
the following dimensions:
D = 161mm
L = 495mm
d = 60mm
H = 90mm
Residence time = 4 min.
The test of this system showed a surprising result
in that very low droplet size was obtained with only

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3000 ppm emulsifying additive at an energy input
considerably less than that of Example 2.
At a ratio of internal phase to external phase of
95:5, and a temperature of 66°C, droplet sizes of 4
microns were achieved with 3000 ppm surfactant at 1.5 x
106 Watt~s/m3. The results of these tests are
summarized below i:n Table III.
TABLE III
TEST SURFACTANT P/Q DROPLET DIAMETER
(ppm) (Watt~s/m3) (microns)
1 3000 0.1 x 106 7.0
2 3000 1.0 x 106 4.5
3 3000 1.5 x 106 4.0
4 3000 2.0 x 106 3.5
It should be noted that the improved results
obtained accor~~ing to the invention were obtained
without the ne~ess:ity of a premixing tank as in Example
2 and U.S. Patent No. 4,018,426.
Furthermore, the procedures according to the
invention yielded droplet size distribution factors, as
described abov~a, of less than 1, indicating a largely
uniform droplet size throughout the emulsion.
Emulsions prepared in accordance with the present
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invention are an excellent alternative for the
transportation of viscous hydrocarbons. The emulsion
can be broken through known techniques once the
emulsion has :reached its destination.
It is to be understood that the invention is not
limited to th~~ illustrations described and shown
herein, which are deemed to be merely illustrative of
the best mode;a of carrying out the invention, and which
are susceptib:Le of 'modification of form, size,
arrangement o:E pants and details of operation. The
invention rather is intended to encompass all such
modifications which are within its spirit and scope as
defined by th~~ claims.
22

Representative Drawing