Note: Descriptions are shown in the official language in which they were submitted.
~lS~
This invention relates to a method and apparatus for emulsi-
fying immisciblefluids. Emulsions can be simplistically visual-
ized as one discontinuous internal phase or fluid enveloped in
a second dissimilar continuous external phase or fluid. In gen-
eral, emulsions fall into two broad categories - oil-in-water
emulsions wherein the oil is the discontinuous internal phase
and the water is the continuous external phase, and water-in-oil
emulsions, where the ahove rules are reversed. In addition, there
can be multiple emulsions such as water-oil-water emulsion,
wherein there is a discontinuous internal water phase surrounded
by a discontinuous external oil phase suspended in a continuous
water external phase; or an oil-water-oil multiple emulsion,
wherein the above roles are reversed, (i.e. in all liquid membrane
systems).
Emulsions~ whether they are water-in-oil or oil-in-water
are fu~ther characterized as being 'llow ratio" or "high ratio".
Low ratio emulsions are generally no higher than 4/1 internal
phase to external phase whereas high ratio emulsions are normally
greater than 4/1, preferably greater than 8/1 internal phase to
external phase. Low-ratio emulsions possess very small droplet
sizes, usually of the order of 1J~, while high ratio emulsions
possess relatively larger particle sizes of the order of 20~or
more.
To make the low ratio t~pe emulsions many kinds of emulsi-
fication devices are available commerc'ally, such as Tekmar Super
Dispax, (trademark for an emulsifier comprising a stator and a
rotor which shears fluids at reIatively high rpm.~ colloid mills
-- 1 --
111562~
ultrasonic vibrators, etc. These devices are, however very
expensive~ ~he simple and inexpensive features of the disclosed
invention, which consists of an ordinary pump and a packed tube,
are obvious. To make the high ratio type emulsions, especially
the very high ratio ones, such as 17/1 W/O emulsion, applicant
knows of no simple, effecti~e and inexpensive device available
except the present invention. The inability of the currently
available emulsification machines in making the latter type emul-
sions is largely because the machines are too powerful to produce
emulsions composed of ~ery fine droplets.
Thus, according to the invention, emulsions are prepared
utilizing an emulsification device comprising an enclosure having
a multiplicity of orifices, at least one of which orifices is an
entrance orifice into which entrance orifice or orifices is intro- ;
duced a number of fluids and at least one of which is an exit orifice
located at a maximum distance from the other orifice or orifices.
The fluids are thereby permitted to flow through the enclosure along
one of its axes, the enclosure being of any cross-sectional profile
perpendicular to the axis of fluid flow. The enclosure is packed
2Q with a material which causes the flow of the fluids to be broken
down into many fine streams, which fine streams, being in intimate
contact one with the other in the enclosure and remix rapidly and
repeatedly resulting in the formation of the desired emulsion which
is discharged from the exit orifice or orifices. The enclosure,
which is typically a pipe or column, can be of any cross-sectional
profile.
B - 2 -
The immiscible fluids which are introduced into the packed
enclosure through the entrance orifice or orifices are fed into the
pack enclosure by fluid feeding means selected from the group con-
sisting of pumping means, gravity conduit means, syringe means and
combinations thereof, in communication with fluid storage means
such as tanks or reservoirs, etc. Preferably single or multiple
pumps are used. The fluids fed into the packed enclosure are intro-
duced into the enclosure either through the same entrance orifice
serviced by the fluid feeding means or each fluid through individual
entrance orifices in close proximity one to another so as to insure
maximum intermixing of the different fluids.
Any number of packed enclosure emulsion generators can be
used, with each generator mixing two or more fluids, or a single
generator can be used with the fluids introduced either simultaneous-
ly through a single entrance orifice or with each fluid fed into
the packed enclosure through individual entrance orifices situated
on the apparatus, it being preferred that all fluids desired to be
mixed are fed into the enclosure simultaneously. If necessary, how-
ever, the individual fluids can be fed into the enclosure sequenti-
ally. The packed enclosure can also be equipped with a return loopconduit whereby either all or part of the emulsion exiting the exit
orifice is reintroduced into the entrance orifice for recirculation
through the packed enclosure either alone or along with added
comporlent fluids. In this way a high degree of emulsification can
be obtained if desired. It is most preferred that separate packed
enclosure emulsifiers be used to prepare individual emulsions when
the final emulsion comprises a multiple emulsion, such as a water/
oil/water system.
B 3 -
5Ç~iz~
The invention will now be described further by way of example
only and with reference to the accompanying drawings, wherein
Figure 1 is schematic cross-section of a packed tube emulsifier
according to the invention. Reerring to Figure 1 of the
drawings, the enclosure 3 has orifices 1 and 2 so as to permit
the entrance of the fluids and the exit of said fluids. These
orifices can be either the normal open ends of a piece of pipe
or, if the enclosure has no "normally" open end the orifice can
be specially constructed in the wall of the enclosure. What is
necessary is that there be at least one entrance orifice and one
exit orifice. Preferably these entrance and exit orifices are
situated at the maximum possible distance away from each other
along the axis of fluid flow in the enclosure so as to insure
maximum mixing between the fluids introduced into the enclosure.
It is possible, and in some instances desirable, that there be
multiple entrance orifices in which case each individual fluid
can be introduced into the enclosure through its own entrance
orifice. When multiple entrance orifices are employed they can
be either serially located parallel to the fluid flow or radially
in the enclosure wall in the perimeter of the enclosure defined
by a plane passing perpendicular to the direction of flow in the
enclosure.
The enclosure is packed with a material 4 which causes the
fluids introduced into the enclosure through the entrance orifice
to split into many fine streams and to re-mix rapidly and repeat-
edly resulting in the formation of the desired emulsion. This
material with which the enclosure is packed is packed into the
enclosure in a random manner to as high a degree of density as is
-- 4 --
1~56~
possible, short of plugging the enclosure, i.e. the fluid pres-
sure drop between the entrance and exit may not equal zero. Suit-
able packing material is selected from the group consisting of
steel metal sponge (such as Kurly Kate*), metal shavings, ceramic
chips, Berl Saddle* (porcelain forms available from Fisher stock
~9-191-5), animal hair or plastic brush, metal tubes shorter than
the internal diameter of the enclosure and mixtures of the above.
The preferred materials are metal shavings, metal sponge (such as
Kurly Kate) and Cannon* packing. The latter is a pro-
truded or perforated sheet metal about 1/16 inch in size and inthe shape of a half-moon or half-saddle. The proper choice of
packing material is critical since it has been discovered that
numerous seemingly attractive materials will not function to give
emulsions. Some that will not work are perforated glass beads,
metal Fenske rings, Raschig rings (glass), steel wool, wooden
straw. The usual guidelines for selecting materials to construct
emulsification machines may be followed, i.e. it is better to use
the material which is wetted by the continuous phase rather than
the discontinuous phase of the emulsion to be formed. ~lowever,
this consideration may not be critical if the fluids are sent into
the packed tube by way of a pump to give strong mixing in the tube
or the surfactants used are potent ones to produce the de-
sired type of emulsion.
The length of the enclosure from entrance orifices to exit ori-
fices, the amount of packing, the density of the packing, and the
type of material packed is left to the discretion of the practi-
tioner, depending on the type of emulsion desired, the density of
the fluids used and the final ratio of internal to external phase
* Trade mark
_ 5 _
~-J
l~lS62~
desired.
The component fluids fed into the packed enclosure are
fed into the enclosure by fluid feed means. These fluid feed means
are typically selected from the group consisting of pumps for
each individual fluid or group of fluids or gravity feed tanks and
conduits or syringes for each fluid or group of fluids or any com-
bination of the above. The preferred fluid feed means comprises
pumps for the component fluids.
When preparing multiple emulsions of the water-oil-water
or oil-water-oil type it is possible to use one enclosure wherein
two dissimilar components are added simultaneously to the enclosure
through relatively closely situated orifice (or through the same
orifice) while the third component is added further downstream.
For example, a water and oil combination can be added to
the enclosure in sufficient ratio to give a water in oil (W/O) emul-
sion. Further downstream a separate water stream can be introduced,
in sufficient quantity to result in the w/o emulsion being suspended
in a continuous water phase resulting in a water/oil/water (w/o/w)
emulsion.
Alternatively, separate packed enclosures can be used to
prepare each emulsion, enclosure 1 preparing the w/o emulsion and
enclosure 2 Using the w/o emulsion from enclosure 1 as a feedstream
adding water to the emulsion to yield the w/o/w emulsion. Many
variations in this basic theme can be envisioned and all are included
in the scope of this invention.
The fluids typically used in preparing a water-oil-water
emulsion include an internal water phase wherein is dissolved or
suspended any desirable material such as medicinals, acids, bases,
B
~ - 6
~56Z~
etc. The oil phase typically comprises an oil component, such as
paraffin oil, mineral oil, petroleum distillate, etc. or animal or
vegetable oils, depending upon the use to which the ultimate composi-
tion will be put. In addition, the oil phase may contain a surfact-
ant, i;e. an oil soluble surfacant of HLB smaller than 8, and /or a
strengthening agent. This surfacant and/or strengthening agent may
be the same material. The final water component is the suspending
phase and may comprise the aqueous phase upon which the basic water-
in-oil emulsion is to act (i.e. detoxification, minerals recovery,
etc.) or it may comprise a diluent phase permitting easy injection
either into the body (if in medicinal use) or into a well ~if in
drilling use).
Emulsions formed by the process of the invention are
useful for all of the applications known to those skilled in the
art using liquid membrane emulsions. Illustrative, but non-limiting
examples include the extraction of metals from aqueous streams,
extracting anions and cations from aqueous streams such as the
extraction of copper from leachate and the extraction of uranium
from wet process phosphoric acid, removing undesirable inorganic
and organic compounds such as chromium ion and phenols from waste
waters, separating mixtures of hydrocarbons, removing reaction
products, encapsulating reactants, etc., as well as various bio-
medical uses including the treatment of chronic uremea, the controll-
ed release of medicinals in the body, blood oxygenation, removal of
toxins rom the body, etc.
The emulsions prepared by use of the apparatus of this
invention may have internal phase to external phase ratios ranging
from 1:1 to greater than 32:1, preferably 1:1 to 3:1 for the low
~ 7 ~
D
.r~
ratio type emulsions and 10:1 or greater, more preferably 17.1 or
greater for the high ratio type emulsions. These apply to both
water-in-oil and oil-in-water type emulsions. The emulsions
prepared by the use of the novel apparatus may have droplet size
from 0.1 ~ to greater than 50 ~ , preferably from about 0.5~to
5~ for the low ratio type emulsions and 6/6~ to 20~ for the high
ratio type emulsions.
Reproductability of the Packed Tube Device and the Effect of the
Amount of Packing Materials
When metal sponge was used to pack the tube connected to
a gear pump, the amount of the metal sponge used is important in
determining the number of recycles needed to make a high ratio
emulsion. Table I shows that when 9.5 gm of the metal sponge were
used, 3 cycles of the feed phase (oil and water) were required to
make an emulsion of 18/1 ratio (94~ internal phase), whereas only
2 cycles were required when 28.5 gm of the metal sponge were used
and 1 cycle was needed to emulsify more than 90% of the feed when
57 gm of the metal sponge were used. A cycle is de~ined as a
once-through operation.
Table II shows the results of the duplicate runs. The
drop sizes obtained are identical or close to those in Table I,
indicating the excellent reproductibility of the packed tube device.
In addition to drop size, flow rate (c.c/min.), pressure drop across
the tube, and viscosities at various shear rates were measured and
summarized in the Tables II and III.
When the surfactant was changed from ENJ-3029* to ECA-4360*
both polyamino surfactants, the emulsions made were quite similar
in terms of drop size, time needed for complete emulsification, and
B - 8 -
~S52~
viscosities at various shear rates (Table IV). Since these two
polyamine surfactants are very close in chemical structure, these
data further illustrate the reproductibility of the device's
performance.
Packed Tube vs. Kenics and Pump
Although the packed tube, like the Kenics* mixer, which
is a static mixer is a type of static or motionless mixer, it is
much more effective in making high ratio emulsions than the Kenics
because of the structure difference between the two devices. As
discussed previously, the packed tube is much more densely packed
in a random manner as compared to Kenics.
As shown in TabIe V, while it took 2 cycles to make a
17/1 W/O emulsion with a 1 or 2 metal sponge-packed tube, it took
as many as 18 cycles to produce a similar emulsion with Kenics and
22 cycles with a gear pump alone (witbout connecting to the packed
Sube). The centrifugal pump tested simply could not produce such
desired high ratio emulsion (Table VI).
It is interesting to note that the centrifugal pump was
able to make the relatively low ratio emulsions in the class of the
high r~tio emulsions, such as 4/1 or 5/1, by first making a 2/1
ratio emulsion and then gradually increasing the ratio to 3/1, 4/1
and 5/1 with s~ow addition of the internal phase during the recir-
culation of the feed phase through the centrifugal pump. The ratio
o 5/1 was the highest that could be achieved. When the not-com-
pletely emulsified 6/1 ratio emulsion was recycled many times
through the pump, a large portion of the emulsion was broken and
the remaining emulsion had a ratio of roughly 2/1. The standard
* Trade ~lark
_ g _
B
i5~ ~
lab emulsification equipment used in the liquid membrane project
-- fluted beaker with marine propeller type stirrer proved inca-
pable of making high ratio emulsions.
Packing Materials
Besides metal sponge, nylon brush, animal hair brush and "can-
non" type packing were found to be effective packing materials for
making emulsions. The emulsions of 10/1 and 20/1 W/O ratios made
with a tube packed with nylon brush were quite similar to those
made with metal sponge-packed tube as demonstrated by the viscosi-
ty vs. shear rate date (Table VII). A packed tube of 1 inch indiameter and 5 inch in length was attached to the discharge end of
a 100-400 RPM gear pump. When the pump was used alone, it took 10
times longer than the packed tube in making the 10/1 W/O emulsion.
It was totally unsuccessful in making 20/1 ratio emulsion, even in
a prolonged 1 hr. operation, whereas using a tube packed with
metal sponge, nylon brush or animal hair brush made the 20/1 ratio
emulsion in several minutes (Table VII).
"Cannon" packing is a small, half-cylindrical shape material.
It is also very effective in forming high ratio emulsions, such
as 17/1 W/O emulsion.
Using Berl Saddle, an emulsion of 20/1 ratio was made, where-
as using stainless steel sponge, "Cannon" packing, and nylon brush
and bristle brush, emulsions of 33/1 ratio were successfully made.
Using the same experimental set-up and procedure, it was found
that metal Fenske rings with 6 inch diameter, steel wool packing,
wooden straw packing, and perforated glass beads, and Raschig
rings did not work, i.e., they did not produce any emulsion with
-- 10 --
~1 ,,
high internal to external phase ratio.
Use of a Packed Tube to Make Low Ratio Emulsions
The packed tube is also effective in making low ratio
emulsions with uniform droplet size. ~s shown in Table VIII, when
a tube which was packed with 2 metal sponges and connected to a
centrifugal pump was used, drop size distribution of 2 to 3~ was
observed after 2 cycles and 1-2 ~ after 3 cycles. When 3 metal
sponges were used, 1-2 ~ drop size distribution was obtained in 1
cycle. In contrast, 4-14 ~ drop size distribution was produced
when a centrifugal pump was used alone. (Table VIII). Similar wide
drop size distribution was obtained with the lab standard set-up of
fluted beaker and marine propeller type stirrer.
Making Oil-in-Wa*'er Emulsions
The following example shows that a metal sponge-packed
tube is also effective in making oil-in-water emulsions.
The membrane phase was an aqueous solution of 1~ Saponin,
70% glycerol and 29% water. The phase to be encapsulated was a
mixture of toluene and heptane at a wt. ratio of 1/1. The wt. ratio
of the encapsulated phase to the membrane phase was 4/1. Both of
these phases blended at 4/1 ratio were sent to the packed tube via
a gear pump. Specification of the pùmp is given in Table I.
A very stable emulsion of the o/w type was made by the
pump-packed tube combination. Drop size range of the emulsion was
from 4 to 12 ~ with an average drop size of 8 ~ .
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TABLE V
1 Emulsification by Kenics and Gear Pump
2 M - 8% ENJ 30~9, 7% SlOON, 85% D.O.
3 IP - 2% KCl sol'n
4 M/IP - l/16.7
Gear Pum~ - see Table I
6 (I) Kenics (21l diam. 6 stages) and gear pump
7 No, of Cycles ~/0 Emulsification Dro~ Size ~)
8 16th &0 6-20
9 17 98
lO 18 100 6-1
11 (II) Gear Pump
12 20th 95
13 22nd 100 6-20
14 _ BLE VI
EMULSIFICATION BY CENTRIFU _ P~U~ ALon~
16 M - 10~/o ENJ 2039, 90~/0 Diesel Oil
17 IP - 2% KCl
18 Centrifugal pump - Century, 3/4 HP, 3450 RPM
l9 (I) M/IP - 1/4 (M and IP were mixed ~t this ratio and
fed into the pump),
21No. of CYcles Unemulsified IP (~ 8/o)
22 l 63
23 2 45
24 3 50
4 40
26 5 48
27 10 65
28 the above data indicate that the emulsion made had a
29 M/IP ræ.tio ~ 1/2.
30TABLE IV (Cont'd)
31 (II) M/IP ~ 7 1/~ ~~ 1/4 -~ 1/5 -~ 1/6 (M and IP were
32 mixed ~t the 1/2 ratio and fed into the pump. When
33 emulsion was formed, additional IP was added to change
34 the ratio to l/3, 1!4, etc.)
-16-
B
l~S~
l No. of Unemulsified Diam, o~ Emul-
2 M.'IP Cycles IP _ sion Drop (
3 1/~ 1 10
4 2 0 0.5-2
s 1!3 1 o 1-~
6 ~./4 1 o
7 ~.~5 1 0 1-12
8 1/6 1 100 (additi.~nal IP was not
9 emulsified)
When the existing emulsion was recycled many times, almost
ll half of the emulsion was broken, the emulsion left had a
12 M/IP ratio 1/2,
13 TABLE VII
14 M a 8% ENJ 3029, 7% S10QN 85% Diesel Oil
IP - 2% KCl Sol'n
16 (I) M/IP - 1l10
17 1) Gear Pump and Tube packed with nylon needles
18 (Brush)
19 Time Needed to Drop Size Shear Rate Viscosity
20 M~ke Emulsion ~ ) (Sec, 1) (cp)
21 ~n) _ - -
22 ~ 8-12 5 2800
23 10 1600
24 170 420
340 270
26 510 225
27 1020 150
28
29 2~ Gear Pump and tube packed with metal sponge
Time Needed to Drop Size Shear Rate Viscosity
31 M~ke Emulsion ~ ) (Sec, 1) (cp)
32 (min~
33 3-4 8-12 5 2800
34 10 1600
170 420
36 - 340 270
-17-
~ 55~.~
BLE VII (Cont ' d)
2 Time Needed to Drop Size Shear Rate Viscos ity
3 Make Emulsion t~ ) (Sec. 1) (cp~
4 (min~ _
510 220
6 1020 145
7 5 4500
8 1~ 2750
93 ) Gear Pump
10- 20 5 1500
ll(II) M/IP - 1!20
12 1) Gear Pump and tube packed with nylon needles
13 7 8-1? 5 7000
14 10 4200
170 510
16 340 270
17 510 190
18 1020 145
19 5 10000
6500
21 ~.) Gear Pump and tube packed with metal sponge
22 Time Needed Drop Shear Viscos- cp at
23 To Make Emul- Size Rate ity tF 5
24 sion (min) ~ ) (Sec 1) (cp) _ sec~
3 8-22 5 3300 80 6500
26 10 2350 86 5000
27 170 360 102 4300
28 340 233 114 4000
29 510 220 138 3500 .
1020 >150 154 ~800
31 5 6000 164 2500
32 10 4250 180 2800
33 190 4800
34 196 4900
.
-18-
B
~ 6~
1 TABLE VII ~ d)
2 3) Gear Pump
3 Time Needed to Drop Size Shear Rate Viscosity
4 M~ke Emulsion (~ ) (Sec. 1) (cp)
5 (min) _ _
6 60 no emulsion - -
7 Notes: (l) Animal hair brush and "Cannon" packing were
8 also found to be effective in making high
9 ratio emulsions. "Cannon" packing is half-
cylindrical shell with 4 mm height, 3.2 mm
ll diam and 0.5 mm diam. holes on shell.
12 (~) The standard lab equipment, fluted beaker with
13 marine propeller-tyPe stirrer, was ineffective
14 in making high ratio emulsions.
TABLE VIII
16 Us~n~_P~cked Tube to Make Low Ratio of W/0 Emulsions
17 M ~ 1~ ENJ-3029, 5/~ Lix 64 N,* 11% S lOON, 83~/o Isopar M*
18 Internal Reagent for-~Cu Extraction, IR a 14% H~S04, 13
19 CuS04~5H~0, 73% H20
M/IR wt Ratio a 1/1
21 The Dacked tube was connected to the Century centrifugal
22 pump (3/4 H.P.)
23 (I) Packed tube - 2.54 cm diam.~ 14 cm length
24 Packing materials - a ~ Metal sponge
b ~ "Cannon" packing (half cylindrical shells with
26 4 mm height, 3.2 mm diam, 0.5 mm diam. holes on
27 shell)
28 No, of Cycles ~ ~ (psi) Drop Si~e ~ )
29 a b a b
1 1.5 1.5 2-5 2-5
31 2.9 2.-9 2-3 2-3
32 ~ 9-4.4 2.9 1-~ 1-2
33 2.~-4.4 2.9-4.41-~
34 (II) Packed ~ube ~ 2.54 cm diam., 28 cm length,
wt. - 6~ gm (2 m.s.)
*Trademar~.
~, -19-
S62~
1 Cy~e ~ (n~2 VelocitY (cc/min) DroP S
2 l 2.9. 1200 ~-5
3 ~ ~.9-4.4 - 2-3
4 .~ ~.9-4.4 784 1-~
4 2.9-4.4 775 1-2
6 S 4.4 - 1-2
7 Note: p = 1.5 psi when pure water was recirculated.
8 (III) Pac~ed tube - 3 ~etal sponges with a total
9weight of 85.5 gm.
10~ethod of Ma~ing Emulsion
11(no recycle2_____ _ _ Drop Size ~ ~ )
12(1) By centrifugal pump
13 along 4-14
14(~) By centrifugal pump
lSand packed tube 1-2
I
-20-
