Note: Descriptions are shown in the official language in which they were submitted.
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MULTIPLE POLYDISPERSED FUEL EMULSION
The present invention relates to a hydrocarbon
emulsion formation where the emulsion has a plurality of
particle modal distributions and further relates to a
method of transporting the emulsion.
Emulsified hydrocarbon fuels have become increasingly
important as a useful fuel for steam generation in power
plant and other steam raising facilities to replace coal
and petroleum coke, has environmental drawbacks, and
natural gas which is relatively more expensive. The high
cost of natural gas has particular ramifications in the
petroleum processing art and specifically in the steam
assisted gravity drainage technique (SAGD) as related to
the production of heavy oils and natural bitumens. As is
known, the SAGD and congener techniques require the use of
steam turbines for injecting steam into a subterranean
formation to mobilize highly viscous hydrocarbon material.
Conventionally, natural gas has been used to fire the steam
generators, however, this is unattractive from a financial
point of view and has other inherent drawbacks. With the
advent of emulsified hydrocarbons, especially those
manufactured from hydrocarbons or their products from
indigenous hydrocarbon production, it has been found that
the heat content is adequate to burn in a steam generation
environment.
One of the first pioneering fuels in this field was
Orimulsion, manufactured in Venezuela by Bitor, and shipped
worldwide to supply power generation plants. Building on
the success of Orimulsion, other emulsified fuels have been
developed such as MSARn' (Multi-Phase Superfine Atomized
Residue), by Quadrise Ltd. and now further developed by
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Quadrise Canada Fuel Systems, Inc. MSARTM is an oil-in-
water emulsion fuel where the oil is a hydrocarbon with an
API gravity between 15 and -10. Typical oil-water ratios
lie in the range 65% to 74%. Because of the presence of oil
droplets in water, MSARTM is essentially a pre-atomized
fuel. This means that the burner atomizer does not do
mechanical work to produce oil droplets, as in conventional
fuel oil combustion, but that it is the emulsion
manufacturing equipment that produces the oil droplets.
Pre-atomization literally means 'before the atomizer' and
so the MSART"' manufacturing equipment is essentially the
atomizer of this process. Typical mean droplet size
characteristics of MSARTM are around 5 microns, whereas
typical mean droplet size characteristics produced during
fuel oil atomization in a burner atomizer are between 150
and 200 microns. Therefore, the enormous increase in
surface area brought about by producing much smaller
droplets in the MSARTM production process, compared with a
conventional burner atomizer, leads to much more rapid and
complete combustion, despite the fact that there are
significant quantities of water present. In addition, when
MSART"' passes through a conventional atomizer, as it must do
in order to be combusted, 150 - 200 micron water droplets
containing the 5 micron oil droplets are formed. Water
therefore finds itself located in the interstitial zones
between each assembly of oil droplets. This interstitial
water, between the oil droplets, spontaneously vaporizes
and this leads to further break-up of the already small (5
micron) droplets. This process is known as secondary
atomization. Because of this secondary atomization and the
earlier described pre-atomization, MSARTM has been found to
be a particularly effective fuel, with a carbon burnout
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rate of 99.99%. Carbon burnout is obviously an important
aspect of any combustion process and the fact that MSART"'
carbon burnout is so high, substantially reduces the amount
of carbon coated ash that collects in the burner and/or
furnace. As is known, if the carbon burnout is low, then
carbon will deposit with ash and on boiler surfaces and
will effectively lead to the production of coke; this leads
to inefficiencies and/or inoperability in the overall
process. By providing a 99.99% carbon burnout rate, these
problems are obviated.
Whilst the extremely small droplet size associated
with MSART"' has distinct advantages for the combustion
process, it has disadvantages for the handling and pumping
processes because the smaller the droplets, the more
viscous the MSART"'. Therefore, in order to further advance
emulsion fuel technology, present research, conducted by
other organizations, has developed means by which the
extremely small droplet size can be maintained whilst
simultaneously reducing viscosity leading to improvements
in storage, handling and transportation generally.
Consequently, research has gone in the direction of bimodal
emulsions, i.e. emulsions which have two distinct droplet
size peaks in their droplet size profile.
This is reflected in, for example, United States
Patent Nos. 5,419,852 issued May 30, 1995 to Rivas, et al
and 5,503,772, issued April 2, 1996 to Rivas et al, inter
alia. In these references, specific blends of
independently produced and discretely different
characteristic emulsions are used to describe the
invention. The conclusion is made that the bimodal
emulsions can be prepared to reduce viscosity and
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illustrate that the final emulsion is distinctively bimodal
in its physical characteristics.
Although it is desirable to have a bimodal emulsion,
this technology is not without limitation. It is known in
the art that the larger the average particle size is, the
lower the viscosity of the mixture. Unfortunately, the
larger the particles in an emulsified fuel, the greater the
length of time it takes for the oil droplet to combust and
travel down the furnace which results in the requirement
for a longer furnace. In the event that the furnace is of
an insufficient length for the selected fuel, then unburnt
hydrocarbon material and/or smoke become undesirable
attributes. In this manner, the existing technology is
limited by the equipment used which can add costs,
complications and other problems related to pollution in
the overall process.
Given the state of the art, it has now been recognized
that the viscosity drives the overall system towards bigger
oil droplets in the fuel, while the combustion results in
the driving of the system towards smaller oil droplets.
Accordingly, it would be desirable to have a formulation
that results in the change in the particle size
distribution of the fuel emulsion to reduce viscosity, but
also to improve combustion. These latter two properties
are most desirable to provide a very efficient high
enthalpy emulsified fuel. Having the formation of an
emulsion with the above noted properties as a goal, a novel
approach was taken to resolve these properties into an
emulsion.
It was found particularly effective to look at the
packing of particles in the prior art and adopt this
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technology. This had not previously been applied to the
field of emulsions for the purpose of generating a
composite emulsion having the most desirable properties,
namely a broad particle distribution composed of n-modal
distributions, but maintaining, as far as is practically
possible, the n-modal distributions as a single peak or
unimodal distribution.
Representative of the particle packing references was
gleaned from the Journal of Computational Physics 202
(2005), 737-764, and particularly an article entitled
Neighbor list collision-driven molecular dynamics
simulation for non-spherical hard particles. I. Algorithmic
details. A general algorithm for a system of particles
having relatively small aspect ratios with small variations
in size. The article was authorized by Donev et al. A
further article by the same author entitled, Neighbor list
collision-driven molecular dynamics simulation for non-
spherical hard particles. 11. Applications to ellipses and
ellipsoids, Journal of Computational Physics 202 (2005),
765-793, was also reviewed. Other general references in
the spherical packing technology include: the article
Modeling the packing of granular media by dissipative
particle dynamics on an SGI Origin 2000, using DL_POLY with
MPI, Elliott et al; Packing and Viscosity of Concentrated
Polydisperse Coal-Water Slurries, Veytsman et al, Energy
and Fuels 1998, 12, 1031-1039; Is Random Close Packing of
Spheres Well Defined? Physical Review Letters, 6 March
2000, Torquato et al.; and The random packing of
heterogeneous propellants, KNOTT et al.
In view of the prior art in the emulsion field, there
still exists a need for an emulsion which facilitates
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changes in particle size distribution of the fuel emulsion
to reduce viscosity, but also one which has improved
combustion and does not lead to poor carbon burnout. The
technology herein provides for burn optimization of the
emulsion.
By applying the packing models from solid fuel to the
instant technology, it was found that the wider the
particle size distribution, the lower the viscosity of the
emulsion.
The present invention has now collated the most
desirable properties for a fuel emulsion where the final
emulsion is effectively a composite emulsion of at least
two precursory emulsions and which composite emulsion
provides for a unimodal distribution, i.e. a single peak,
emulsion as opposed to bimodal distribution which is
exemplified in the prior art. Unimodal as used herein,
refers to a majority peak with the potential for shoulders,
but absent discrete peaks.
The present invention has successfully unified
unrelated technologies to result in a particularly
efficient composite fuel emulsion.
One aspect of the present invention is to provide a
substantially improved atomized fuel emulsion, which
emulsion is a composite fuel emulsion having very desirable
burn properties, calorific value and which can be custom
designed for burning in any furnace or burning arrangement
which is vastly different from the prior art.
According to a further aspect of one embodiment of the
present invention, there is provided an emulsified
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hydrocarbon fuel, comprising a composite of a plurality of
hydrocarbon-in-water emulsions, the composite emulsion
having a unimodal hydrocarbon particle distribution, the
hydrocarbon being present in an amount of between 64% and
90% by volume.
As noted herein previously with respect to the prior
art, high oil content in the oil-in-water emulsion has been
recognized previously, however, the emulsion formed in the
prior art is bimodal. By making use of the instant
technology, not only is the hydrocarbon content exceedingly
high, but the viscosity is reduced for the overall system
relative to the independent viscosities of the precursor
emulsions forming the composite and further, the carbon
burnout rate is particularly attractive at greater than
four nine effectiveness.
The precursor emulsions may contain the same
hydrocarbon material or different hydrocarbon materials
depending upon the specific use of the emulsion. In
addition, the particle size distributions and droplet size
may be the same or different. In the instance where the
size distributions are the same, the hydrocarbon material
will be different in the discrete emulsions. As a further
possibility, the composite emulsion may be a composite
emulsion combined with a hydrocarbon in water emulsion.
Similar to that noted above, the composite emulsion and
hydrocarbon in water may comprise the same or different
hydrocarbon material, same or different droplet size and/or
the same or different particle size distribution.
According to a further aspect of one embodiment of the
present invention there is provided a method of formulating
a composite emulsion made from different hydrocarbon
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materials which possess widely differing viscosities and
therefore widely differing emulsion preparation
temperatures. Consequently, the precursor emulsion which is
made at the lower temperature can be used as a cooling
agent when mixed with the precursor emulsion which is made
at the higher temperature. This obviates or reduces the
need to use heat exchangers to reduce the temperature of
emulsions which are made above 100 deg C to below 100 deg C
prior to storage.
According to a further aspect of one embodiment of the
present invention there is provided a method of formulating
a composite emulsion having unimodal particle distribution
with reduced viscosity relative to precursor emulsions used
to form said composite emulsion: providing a system having
an n-modal particle distribution; forming a precursor
emulsion for each n-modal distribution present in the
system, each precursor emulsion having a characteristic
viscosity; and mixing precursor emulsions to form the
composite emulsion with a unimodal size distribution and
reduced viscosity relative to each precursor emulsion.
As briefly discussed herein previously, it has been
found that by making use of the composite emulsion, the
same has a viscosity which readily facilitates
transportation, despite the high content of hydrocarbon
material present in the emulsion. It is believed this is
due to the unimodal particle size distribution which,
inherently provides a broader spectrum of particle sizes.
This, in turn, commensurately provides advantage in mixture
viscosity.
A still further aspect of one embodiment of the
present invention is to provide a method for transporting
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viscous hydrocarbon material comprising: providing a source
of hydrocarbon material; generating a plurality of
emulsions of the hydrocarbon material, each emulsion having
a characteristic viscosity, each emulsion having a
different particle size distribution; mixing the plurality
of emulsions in a predetermined ratio to form a composite
emulsion having a lower viscosity relative to the plurality
of emulsions; and mobilizing the composite emulsion.
A still further aspect of one embodiment of the
present invention is a method of maximizing viscous
hydrocarbon content in an aqueous system for storage or
transport, comprising: providing a hydrocarbon emulsion
having a hydrocarbon internal phase volume sufficiently
high such that the droplets in the emulsion are aspherical;
converting the emulsion at least to a bimodal emulsion
system; forming at least two precursor emulsions from the
system; mixing the precursor emulsions in a predetermined
ratio to effect reduced viscosity; and synthesizing a
composite emulsion from the precursor emulsions having the
reduced viscosity.
A still further aspect of one embodiment of the
present invention is a method of formulating a composite
emulsion having unimodal particle distribution with reduced
viscosity relative to precursor emulsions: providing a
system having an n-modal particle distribution; forming a
precursor emulsion for each modal distribution present in
the system; each the precursor emulsion having a
characteristic viscosity; forming a plurality of composite
emulsions each having a unimodal size distribution and
reduced viscosity relative to each the precursor emulsions;
and mixing the composite emulsions to form an amalgamated
composite emulsion having a unimodal particle distribution
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and reduced viscosity relative to the viscosity of the
composite emulsions.
In accordance with another beneficial aspect of one
embodiment of the present invention, it was found that the
HIPR (High Internal Phase Ratio) emulsions, which have
extremely high hydrocarbon material content in the
emulsion, could also be transported efficiently. By making
use of the high internal phase ratio emulsion, it was
discovered that these emulsions can be converted to at
least a bimodal or n-modal emulsion system depending upon
the number of particle size distributions within the HIPR
emulsion and then these individual bimodal emulsions could
be formed into precursor emulsions and mixed to form a
composite emulsion in accordance with the methodology
previously discussed herein. In this matter, aspherical or
substantially non-spherical oil in water particles can be
reconfigured or converted into discreet modes for
individual emulsion synthesis with subsequent mixing for
composition of a more favorably transportable composite
emulsion. This has particular utility in permitting
mobilization of high hydrocarbon content material without
expensive unit operations conventionally attributed to
processes in the prior art such as pre-heating, the
addition of diluents or other viscosity reducing agents.
The material can simply be converted, to a composite
emulsion and once so converted, inherently has the same
transportation advantages of the composite emulsions
discussed herein previously.
A method of modifying at least one of the combustion,
storage and transportation characteristics of an emulsion
during at least one of pre-formation, at formation and post
formation, comprising: providing an emulsion; treating the
emulsion to a unit selected from the groups consisting of
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additive addition, mechanical processing, chemical
processing, physical processing and combinations thereof;
and modifying at least one characteristic of the
characteristics of the emulsion from treatment.
Having thus generally described the invention,
reference can now be made to the accompanying drawings
illustrating preferred embodiments and in which:
Figure 1 is a schematic illustration of the overall
synthesis mechanism of the instant technology;
Figure 1A is a schematic illustration of a variation
in the overall synthesis mechanism of the instant
technology;
Figure 2. is a graphical illustration of particle size
as a function of shear;
Figure 3A and 3B are graphical illustrations of
viscosity as a function of droplet size ratio;
Figure 4 is graphical illustration of percentage of
oil in the emulsion as a function of further length;
Figure 5 is a graphical illustration of two precursors
and a composite emulsion of a surfactant in 70% NE Alberta
bitumen for a median particle size of 5 pm and 24 pm;
Figure 6 is a graphical illustration of the composite
emulsion viscosity for varying percentages of the same
median particle size;
Figure 7 is a graphical illustration of a two modal
distribution for North Eastern Alberta bitumen particles
with two particle sizes (5 microns and 10 microns);
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Figure 8 is a graphical illustration of viscosity as a
function of the percentage of 5 micron MSARTM used in the
precursory emulsion and percentage of 10 micron MSARTM used
in the second precursory emulsion;
Figures 8A through 8C illustrate particle
distributions for composite emulsions formed from the 5 and
micron individual emulsions for 5 and 10 micron
percentages of 20% and 80%, 50% and 50% and 80% and 20%,
10 respectively;
Figure 9 illustrates the individual distributions for
a 6 micron 12 micron mode where both precursory emulsions
are formed using a surfactant and a 70% content of refinery
residue;
Figure 10 illustrates a viscosity as a function of the
MSARTM mixture composed of 5 microns in the first emulsion
and 12 microns in the second emulsion;
Figures 10A through 10C illustrate the result of the
particle distribution in the composite emulsions for the 6
and 12 micron particles in the following percentages: 20%
and 80%, 50% and 50% and 80% and 20%, respectively;
Figure 11 is a graphical illustration of the
precursors where emulsion number 1 comprises 6 micron
median particle size distribution and emulsion to a 16
micron median particle size distribution;
Figure 12 is a graphical representation of the
viscosities of the MSARTM mixtures composed of 6 micron and
16 micron 80/100 Asphalt MSARTM%
Figures. 12A through 12C illustrate varying
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percentages of 6 micron and 16 micron particles, namely 20%
and 80%, 80% and 20%, and 50% and 50%, respectively;
Figure 13 is front view of a burner where the
illustration is of a North Eastern Alberta bitumen MSARTM
fuel number 1 being combusted;
Figure 14 is a side view of the flame illustrated in
Figure 13;
Figure 15 is an illustration of the coke deposits on
the nozzle subsequent to the combustion of the fuel being
burned in Figures 13 and 14;
Figure 16 is a view similar to Figure 15 after a
second burning run of MSART"' fuel 1;
Figure 17 is a view of the combustion from the burner
of the North Eastern Alberta bitumen MSART"' fuel 2;
Figure 18 is a photograph of the nozzle after
combustion of the MSART"' fuel 2 illustrating the coke
deposit;
Figure 19 is a figure depicting the flame generated
from the burning of the North Eastern Alberta bitumen MSARTM
composite fuel between the MSAR'1'f' fuel 1 and MSART" fuel 2;
Figure 20 is a side view of the flame of Figure 19;
and
Figure 21 is an illustration of the burner nozzle
illustrating the minimum deposition of coke on the nozzle.
It will be noted that throughout the appended
drawings, like features are identified by like reference
numerals.
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Referring now to Figure 1, shown is the overall
synthesis mechanism globally denoted by numeral 10. The
synthesis mechanism includes two broad steps denoted by
numerals 12 and 14. In step 12, a hydrocarbon material 16
is mixed with water 20 containing a surfactant 18 and the
material, as a mixture, is mixed in a mixing device 22.
The hydrocarbon material may comprise any hydrocarbon
material fuel, non limiting examples of which include
natural gas, bitumen, fuel oil, heavy oil, residuum,
emulsified fuel, multiphase superfine atomized residue
(MSART"'), asphaltenes, petcoke, coal, and combinations
thereof. It is desirable to employ hydrocarbon material of
less than 18 API. The use of an emulsion stabilizer (a
chemical composition which presents premature phase
separation of the emulsion), stabilizes phase separation.
The surfactants are useful for this as well as a host of
other members in the class of stabilizers.
In terms of the surfactants, it is well known in this
art that the surfactants may be non-ionic, zwitterionic,
cationic or anionic or mixtures thereof. Further, they may
be in a liquid, solid or gaseous state. It is well within
the purview of the scope of this invention to use
combinations of materials to achieve a properly dispersed
system normally attributable to emulsions.
The mixer may comprise any suitable mixer known to
those skilled in the art. Suitable amounts for the
emulsion stabilizer or surfactant comprise between 0.01% by
weight to 5.0% by weight of the emulsion with the
hydrocarbon comprising any amount up to 90% by weight. In
the example, a mixer such as a colloidal mill, is used.
Once the materials are subjected to the colloidal mill a
first precursor emulsion 24 is generated. Similar steps
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are effected to result in the second precursory emulsion
24', with common steps from the preparation of emulsion one
being denoted by similar numerals with prime designations.
Once precursor emulsion 24 and the second precursor
emulsion 24' are formed, the two are introduced into a
mixing device 26 which may comprise a similar shear
apparatus as the colloidal mill or more likely a further
selected device such as an in-line static mixer.
In the individual emulsions 24 and 24', one of the
emulsions will have a smaller average particle diameter
relative to the second emulsion. These are then mixed
together in a predetermined ratio to form the composite
emulsion 28 which is a multiple polydispersed fuel
emulsion. The preset ratio can be determined by making use
of a particle packing algorithm such as that which has been
set forth in the discussion of the prior art. The use of
this algorithm was previously applied to solid based rocket
fuels and by making use of the algorithm in the synthesis
of a composite emulsion, a very successful result has been
encountered. One of the particularly attractive results is
that the composite emulsion has a viscosity that is less
than the viscosity of the precursor emulsions by a factor
of between 3 and 5 times the viscosity of the precursor
emulsion containing the small droplets. A further
advantage that flows from this unification of unrelated
technologies is the requirement for lower preheat
temperatures in the composite emulsion as opposed to those
preheat temperatures required for the previous or precursor
emulsions.
Conveniently, the composite emulsion also has been
found to have much improved dynamic and static stability
and handling (anything in-between manufacture and burner
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tip, e.g. storage, valves, pipes, tanks, etc)
characteristics and therefore easier storage and
transportation possibilities. In burn testing, the
composite emulsions provided greater than 99.99% carbon
burnout, despite the fact that the emulsion contained a
high percentage of the hydrocarbon material in water.
Referring now to Figure lA, shown is a variation of
the overall arrangement shown in Figure 1. In this
embodiment, the process may be modified at various stages
to effect the transportation storage and/or combustion of
the individual components within the emulsions or the
composite emulsion itself. In this manner, Figure 1A
provides for modification of at least one of the above
noted aspects by modification at the pre-synthesis mixing
point prior to the surfactant and water entering the mill
22 as denoted by numeral 30 or as a further option by
modifying the hydrocarbon prior to introduction to the
mill, this step being indicated by numeral 32. As a
further possibility, the emulsion may be modified at the
point of fabrication, denoted by numeral 34 or subsequent
to formation at 36. In respect of similar numerals with
prime designations, these steps apply to emulsion number 2
designated by numeral 24'. As a further possibility, once
the first emulsion 24 and second emulsion 24' are
introduced, they may modified at mixer 26 denoted by
numeral 38 or subsequently modified once the composite
emulsion 28 has been formed. This step is denoted by
numeral 40.
By the variation in this process as depicted by Figure
1A, the emulsion may be modified in terms of combustion,
storage and/or transportation characteristics during at
least one of pre-formation, at formation and post formation
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where the modification involves a unit operation selected
from at least additive addition, mechanical processing,
chemical processing and physical processing, as well as
combinations thereof. The additive addition will be
discussed herein after.
Referring now to Figure 2, shown is a schematic
graphical illustration of particle size as a function of
the amount of shear. This permits the selection of
different particle size distributions for the emulsions by
changing the amount of shear used to make particles for the
emulsion. It is known that the amount of shear is related
to the average particle size and width of distribution as
shown in Figure 2. The lowest droplet size is related to
the parameters used to formulate the emulsion. The shear
amount is increased by increasing the residence time in the
mixing device, or increasing the speed at which the
rotatable mixing device rotates.
It has been found that it is convenient to maintain
the surfactant concentration relative to the oil content as
substantively the same for precursor emulsions for purposes
of stability. This is exemplary only, variations in the
concentration of the surfactant can occur depending upon
the final desired characteristics for the composite
emulsion. In situations when different surfactants are
used for different composite emulsions, the surfactants
will, for course, be compatible. The examples have been
discussed previously and other examples will be apparent to
those skilled.
Referring now to Figures 3A and 3B, shown are
schematic graphical illustrations of viscosity as a
function of a ratio of small droplets versus big droplets
with the larger droplets being represented on the left hand
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side of the graphs.
Referring now to Figure 4, shown is a schematic
illustration of the percent of the oil content in the
emulsion as a function of the length of furnace required to
completely burn the fuel.
Referring now to Figure 5, shown is pre-mix particle
distributions for a bimodal system where numeral 1
represents an emulsion containing surfactant with 70%
North Eastern Alberta bitumen with the balance comprising
water. The first distribution was formulated using a high
shear mixer at a high revolution. The median particle size
in this distribution was 5 microns whereas in distribution
number 2, the median particle size was 24 microns. In the
premix it is evident that each emulsion possesses a
distinctly different mean and median droplet size.
Figure 6 is a graphical representation of viscosity as
a function of percentage of 5 micron MSAR- emulsion and 24
micron MSARTM used in the mixture. Inset Figure 6A is a
distribution representation for a 20% 5 micron and 80% 24
micron mixture having a characteristic viscosity indicated
by the arrow in the graph of Figure 6, whereas Figure 6B is
an inset where the mixture or composite emulsion contained
80% 5 micron particle size and 20% 24 micron particle size
with the arrow pointing in Figure 6 to the characteristic
viscosity. Finally, inset Figure 6C depicts a 50/50 blend
of 24 micron and 5 micron particles with the characteristic
of viscosity being indicated by the arrow. From a review
of Figures 6A through 6C, it is evident that the particle
distribution representations are effectively unimodal
despite containing two individual emulsions which
independently possess distinctly different mean and median
droplet sizes.
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As a further representation, Figure 7 provides a North
Eastern Alberta bitumen particle distribution where there
is a greater degree of overlap between the two modal
distributions in view of the median particle size. In this
representation, similar materials were used with respect to
the previous discussion with the 5 micron median particle
distribution being represented by numeral 1 which occurred
at a relatively high speed, whereas peak 2 comprises medial
particle distribution of 10 microns which was created at a
lower speed. This is an example; mixing can occur in a low
and high intensity mixer with the rpm selected based on
final requirements.
Figure 8 illustrates a viscosity as a function of the
percentage of 5 micron MSAR''"' used in the precursory
emulsion and percentage of 10 micron MSARTI" used in the
second precursory emulsion. Insets 8A, 8B, and 8C
illustrate particle distributions for composite emulsion
formed from the 5 and 10 micron individual emulsions for 5
and 10 micron percentages of 20% and 80%, 50% and 50%, and
80% and 20%, respectively. Individual arrows from each of
insets 8A through 8C are representative of the viscosity of
the individual final composite mixtures of insets 8A, 8B
and 8C.
In Figure 9, a further hydrocarbon material was
employed for synthesizing the composite emulsion. Figure 9
illustrates the individual distributions for a 6 micron and
12 micron mode where both precursor emulsions were formed
using a suitable surfactant and a 70% content of refinery
tank 9 with a balance of water. The contents of the
refinery residue are approximately 10% gas oil and 90%
viscous hydrocarbon material. The 6 micron distribution
was generated at a relatively high speed, whereas the 12
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micron was generated at a lower speed.
Figure 10 illustrates the viscosity as a function of
the MSART"' mixture composed of 5 microns in the first
emulsion and 12 microns in the second emulsion. Figures
10A through 10C illustrate the results of the particle
distribution in the composite emulsion for the 6 and 12
micron particles in the following percentages: 20% and
80%, 50% and 50% and 80% and 20%, respectively.
As is evident from the inset illustrations, each has a
characteristic viscosity indicated on the graphical
representation of Figure 10. Further, similar to the
previous examples noted, the composite emulsion in all
cases is effectively unimodal and accordingly provides a
broad particle size distribution.
Figure 11 tabulates the characteristics of pre-cursor
emulsion where emulsion number 1 comprises 6 micron median
particle size distribution and emulsion 2 a 16 micron
median particle size distribution. In this example, the
surfactant was employed as the surfactant with the
hydrocarbon material comprising 70% 80/100 Asphalt with the
balance being water. The 6 micron distribution was
formulated using the mill at a relatively high speed where
the 16 micron was synthesized at a lower speed.
Similar data to the examples presented previously are
presented in Figure 12 where the viscosity is represented.
Inset Figures 12A through 12C represent specific composite
emulsion formulations of 6 and 16 micron distributions in
the following amounts: 20% and 80%, 80% and 20%, and 50%
and 50%, respectively.
Once again, the composite emulsion demonstrates a
unimodal particle distribution with characteristic
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viscosities for each of the insets 12A through 12C.
From the results, it is evident that the instant
methodology results in the desirable formulation of
unimodal composite fuel emulsion from discrete precursory
emulsions. It is known that the oil content or hydrocarbon
material content of oil in water emulsions of the prior art
is generally limited to approximately 70% since greater
content beyond this point increases the viscosity of the
emulsion exponentially. This is clearly contrary to the
desired properties that have been achieved with the instant
methodology. By making use of the protocol as set forth
herein, the oil content can be increased to up to 90%
whilst still maintaining relatively low viscosities
compared with conventional or HIPR emulsification. It is
believed that the packing of the droplets in the multiple
polydispersed fuel emulsions set forth herein is
significantly better in normal emulsions not presenting
unimodal distributions.
A host of very useful features flow from the use of
this methodology not only to make an improved emulsified
fuel with higher carbon burnout than the individual
emulsions in the composite, but also the lower water
requirement for transportation.
As discussed briefly, one of the major advantages of
the instant technology is that HIPR emulsions which are
characteristically composed of aspherical particles which
are generally polyhedral which can be converted into
individual emulsions and then subsequently combined to form
a composite mixture having the advantages that flow from
the instant technology. In this manner, the HIPR emulsions
can be converted to provide the desirable properties of a
composite emulsion in terms of having a wider particle
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-22-
distribution with reduced viscosity and improved
combustion. It is a well known fact that HIPR emulsions
have exceptionally high viscosities, and are very shear
thinning. It has not been previously proposed to convert
HIPR emulsions into discrete emulsions for a combination
such as that which is disclosed herein to provide for
reduced viscosity with enhanced combustion. It has not
been previously recognized to employ HIPR emulsions which
are capable of having a 99.99% carbon burnout rate.
With respect to convenience of use, the emulsion
technology set forth herein allows the emulsion to be
designed for the furnace or burning arrangement
individually as opposed to having to design a furnace to
specifically burn the emulsion. The cost savings on this
point are extremely substantial; the modification of the
emulsion is obviously a much less involved exercise than
having to design and fabricate a new piece of expensive
equipment.
Further, depending upon economics and the requirements
for the composite emulsion the precursor emulsions are not
limited in number and are well within the scope of the
instant technology to provide an n-modal system. The
individual emulsions would have to be formulated and then
subsequently mixed together to form the composite emulsion
as an attendant feature to this aspect of the invention,
individual groups of emulsions may be mixed to form
composite emulsions and the so formed composite emulsions
then further mixed to form an amalgamated emulsion of
individual composite emulsions. In terms of bi or multi-
modal distributions used to form a composite emulsion, the
composite may be reintroduced into a shear or mixing device
to form a processed composite emulsion.
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CA 02571671 2006-12-19
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Having now delineated the details of the invention,
reference will now be made to the following example:
EXAMPLE
Three fuel types were examined:
1) North Eastern Alberta bitumen MSART" fuel 2 with
particle size 5.5 pm;
2) North Eastern Alberta bitumen MSART"' fuel 1 with
particle size 22 pm; and
3) 50/50 mixture of North Eastern Alberta bitumen
MSART"' fuel 1 and MSARTI" fuel 2 with particle size 5
- 22 pm.
Experiments began with the fuel having the larger droplet
(MSART"' fuel 2 ) .
A fuel firing rate of 30 kg/h, lower than the normal
36kg/h, was used to avoid possible fuel plugging since the
fuel contained larger sized droplets. The same fuel firing
rate was used for the other fuel types to maintain
consistency among the conditions.
The initial temperature for the MSARTM fuel 1 was a fuel
temperature of 85 C and was slowly increased to 100 C,
based on the flame characteristics observed.
Other parameters followed for the protocol were:
Atomizing air temperature of 108 C;
78 - 79 C at burner;
Combustion air temperature of 108 C
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CA 02571671 2006-12-19
= -24-
02 .6.7, 6.2
Parameters observed for the MSARTM fuel 2 fuel type were:
An atomizing air temperature of 84 C;
Combustion air temperature of 84 C;
A fuel temperature of 65 C; and
02 5.2, 5.3
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CA 02571671 2006-12-19
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CA 02571671 2006-12-19
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CA 02571671 2006-12-19
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CA 02571671 2006-12-19
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CA 02571671 2006-12-19
-29-
From a review of the data presented in the tables and,
with specific reference to Table 3 it is evident that the
MSAR''"' blend or the composite emulsion provides a high
thermal efficiency which exceeds the value for the 5 pm
MSART"' and approximates the 22 pm MSAR''"
In furtherance of the significant benefits that have
been realized in the composite emulsion, Table 2 provides
flue gas emission data which again provides evidence that
the NOX and SOZ emissions are very appealing from an
environmental point of view in the blend. It is
particularly note worthy that the MSARTM blend composite has
a lower carbon content in the particulates and a lower CO
concentration in the flue gas than the precursor emulsions,
indicating a much better carbon burnout for the composite
emulsion.
Perhaps the most appealing group of data is provided
for in Table 3 where the thermal heat transfer data is
indicated. Reference to the percent of thermal fuel input
extracted in the examples clearly provides for very
favourable energy for the composite relative to that for
natural gas.
The data presented herein is further corroborated by
Figures 13 through 21.
Referring to Figure 13, shown is a photograph of a
burner where the North Eastern Alberta bitumen MSARTM fuel 1
is being combusted. The flame shape is illustrated in the
Figure.
Figure 14 illustrates a side view of the flame from
the burner of the fuel being burned in Figure 13.
Figures 15 and 16 illustrate the coke deposit on the
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-30-
nozzle of the burner after the first run of burn, while
Figure 16 illustrates the coke deposit on the nozzle of the
burner after a second run; the difference being fairly
significant.
Figure 17 provides a view of the burner during the
burn of the North Eastern Alberta bitumen MSARTI" fuel 2.
Figure 18 illustrates the coke deposit on the nozzle
of the burner subsequent to the combustion of the MSART'"
fuel 2.
In Figure 19, the burning of the composite emulsion is
indicated in the photograph. It is interesting to note
that the flame shape is much more consolidated than the
flame shape of the individual precursor emulsions when
burned. This is further corroborated by Figure 20, which
shows a fairly significant flame length and intensity when
taken from a side view of the burner. As discussed herein
previously with respect to the burn characteristics and
other features of the composite emulsion, Figure 21
illustrates the cleanliness of the flame; the coke deposit
on the nozzle subsequent to burning is virtually non-
existent when one compares this illustration with the coke
deposits from Figure 16 relating to the combustion of MSART"
fuel 1.
CONCLUSIONS:
Having regard to the photographic data and physical
data presented during the testing of the composite
emulsion, it is evident that the composite emulsion has
many significant benefits over the burning of the precursor
emulsions and in many cases approximates the beneficial
features of burning natural gas. Obviously, the combustion
of the composite emulsion provides a more desirable energy
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-31-
output from a lower monoxide emission, lower coke deposits
at the burner nozzle, lower sulfur dioxide emissions among
other very desirable properties. As evinced form the
Figures, the composite emulsion flame characteristics
provide for a much brighter and more stable flame with less
brownish discolouration, lower carbon monoxide emission
among other features.
The embodiments of the invention described above are
intended to be exemplary only. The scope of the invention
is therefore intended to be limited solely by the scope of
the appended claims.
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