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Eric COTTELL

Ultrasonic Fuel-Water Emulsifier





Newsweek (June 17, 1974): "A Solution to Air Pollution"
John F. Pearson: Popular Mechanics (November 1972); "A Furnace That ‘Burns’ Water"
Eric C. Cottell: US Patent # 3,749,318 ~ "Combustion Method and Apparatus Burning an Intimate Emulsion of Fuel & Water"
E. Cottell: US Patent # US Patent # 3,941,552 ~ "Burning Water-in-Oil Emulsion Containing Pulverized Coal"
E. Cottell: US Patent # 4,048,963 ~ "Combustion Method Comprising Burning an Intimate Emulsion of Fuel and Water"
Patents by E. Cottell @ Espacenet (European Patent Office)

Newsweek (June 17, 1974) 
A Solution to Air Pollution

In the wake of the energy-crisis a 50-year-old British-born inventor named Eric Cottell has come up with an ingeniously simple and economically practical solution -- one that is now exciting industry and government officials alike.

In the conventional combustion process, fuel is combined with air and turned. The result is carbon dioxide, water vapor and heavy oxides of nitrogen, which are a prime cause of chemical smog. Cottell reasoned that if water could largely replace air as a source of oxygen in combustion, this would avoid the large amounts of nitrogen introduced by the air -- and thus eliminate much of the noxious nitrogen oxides.

To accomplish this, he turned to a device he had patented 22 years ago -- an ultrasonic reactor that emulsifies heavy liquids and is widely used today to prepare such products as Worcestershire sauce, ketchup, cosmetics and paint. By refining the reactor, Cottell was able to break water into particles about one fifty-thousandth of an inch in diameter and to disperse them evenly in oil (or gasoline) to create an emulsion that was 70 percent oil and 30 percent water. When this emulsion was burned, Cottell found :

(1) that there were far fewer waste products and

(2) that the small water droplets expand on heating, then explode into steam, in turn shattering the oil into even finer particles, and thus increasing the surface area of the fuel exposed for burning.

Last month Cottell divided his time between Washington, in talks with officials of the Federal Energy Office, and Detroit, where he consulted with engineers working to meet the tight 1976 automobile-emission requirements. So far, auto tests have shown that with an ultrasonic reactor attached to a carburetor, a car can get almost DOUBLE the normal miles per gallon of gasolinge -- with neglible exhausts. Cottell's company, Tymponic Corp. of Long Island, N.Y., is also about to produce units for home oil burners that will be no larger than a flashlight and cost $100 to $150.

Last winter, two Long Island schools converted to Cottell's system, and both reduced their fuel usage by about 25%. Adelphi University reports that it saved more than 3,500 gallons of oil per week! -- and reduced soot output by 98 %."




Popular Mechanics (November 1972)

"A Furnace That ‘Burns’ Water"

by John F. Pearson


A revolutionary combustion system makes it possible to ‘burn’ emulsions of fuel and water. It works in a car engine as well as an oil furnace – and cuts pollutants, too.
 

It’s impossible. An oil burner simply can’t run on a fuel that is one-third water -- tap water, at that. But I recently saw it done.

The demonstration was at the Bayville, NY home of Eric C. Cottell, a British-born engineer and inventor. The gadget that made the "impossible" happen is a Cottell invention called the Ultrasonic Reactor -- a device resembling a long, slim electric motor. It contains a crystal stack at one end and a mixing chamber at the other.

When a 60-cycle current is applied, the crystals vibrate at 20,000 cycles per second, turning the reactor into a "super-blender". As shown in the diagram, oil and water (70% oil, 30% water) flow into the reactor, where a terrific vibrating force causes water and oil molecules to rupture. The two liquids form an emulsion in which tiny particles of water are dispersed throughout the oil. When this happens, says the inventor, the surface area of the water is increased millions of times. Thus, when the emulsion hits the furnace’s combustion chamber, the water "explodes" into superheated steam, adding to the energy ouput of the oil.

In hundreds of tests of his system, Cottell has found that ordinary boilers run at efficiencies close to 100% -- as astounding result that neither he nor leading combustion experts can explain. In the demonstration I saw, gauges indicated that the emulsion produced the same amount of heat as a 100% oil fuel.

In addition to stretching fuel, the system reportedly produces fewer pollutants than standard oil combustion. The fact that one-third less oil is burned is a key anti-pollution factor.

Though Cottell sees many potential applications for the reactor -- in auto, ship and plane engines, for example -- he thinks the best immediate application is in heating plants of large apartment buildings.

"This is by far my most exciting invention", says Cottell, who holds patents in the fields of ultrasonics, hydraulics, and chemistry.



US Patent # 3, 749,318

( US Cl. 239/102 ~ July 31, 1973 )

Combustion Method and Apparatus Burning an Intimate Emulsion of Fuel and Water

Eric C. Cottell

Abstract --- A combustion apparatus and process in which a water-in-oil emulsion of liquid fuel, such as liquid hydrocarbons, containing from 10 to 50 % water, the emulsion being produced without any substantial emulsifying agent and preferably by sonic agitation, is burned.

The combustion of liquid fuel, such as liquid hydrocarbons, is a standard method of power and/or heat generation. The combustion may be in a system where the heat is transferred to another medium, such as water, with or without boiling the water, or the fuel may be burned in various types of internal combustion engines, such as those operating on Otto, diesel, or other cycle. The amount of oxygen, usually air, is at least about theoretically sufficient for complete combustion of the fuel elements.

Considerable problems have arisen. If there is a very large excess of oxygen, the efficiency of the combustion process is lowered because a considerable amount of the air, including inert nitrogen, has to be heated up. In the case of an internal combustion engine, operating with excessive amounts of oxygen can result in slow combustion, which can overheat and burn out exhaust valves. If the combustion is with amounts of oxygen and fuel more nearly in balance, for example with only a small excess of oxygen, problems arise with incomplete combustion. This can result in excessive amount of carbon monoxide and/or incompletely burned fuel, which may show up as unburned hydrocarbons, soot and the like. Incomplete combustion lowers the combustion efficiency and can also contaminate the equipment. In the case of internal combustion engines, unburned hydrocarbons, carbon monoxide, and oxides of nitrogen, generally symbolized by the formula NOx, are serious atmospheric pollutants as they give rise to photochemical smog and the like. Contamination of NOx from an IC engine usually results when combustion temperature is high.

It has been proposed in the past to introduce streams of water into a burner or to inject water into an internal combustion engine as it operates. This has proven to reduce somewhat incompletely burned fuel deposited in the form of carbon, and in the case of IC engines this can lower NOx production and also in certain cases, such as aircraft piston engines, permit operating for short times at higher power outputs with very rich mixtures which would otherwise burn up the engine. Water injection, however, has serious drawbacks. In the first place, it is very difficult to control relative amounts of water and fuel precisely. Even if the control is maintained to a satisfactory degree, efficiency drops because the water has to be vaporized, with its extremely high latent heat, and heated up in the combustion, which takes further power because of the high specific heat of water vapor. As a result, water injection has only bee practically used in unusual circumstances.

Summary of the Invention

The present invention burns an extremely fine emulsion of water and liquid fuel, normally hydrocarbonaceous fuel, in which the water droplets are dispersed in an extremely fine average particle size. While the present invention is not absolutely limited to the method by which the emulsion is carried out, it is preferred to emulsify by using an ultrasonic probe or other device which agitates the fuel and water to produce an extraordinarily finely dispersed emulsion, because it is the fine dispersion that produces the important new results which will be set out below; mere presence of the water does not.

According to the present invention, if a very fine emulsion is burned, which may have from about 10% to as much as 50% water, extremely clean combustion results, contamination and pollution are minimized, and in a straight atmospheric burner up to 30% of water will give results in which the heat obtained by the combustion is substantially the same as if all hydrocarbon fuel were burned. In other words, with 70% fuel and 30% water, the emulsion will produce the same amount of heating. This surprising result has been repeatedly tested, and while I do not want to limit the present invention to any particular theory, it seems probable that the combustion of the emulsion is so complete that the smaller amount of fuel is completely burned and the same final heat is obtained as if there were no water present. The above statements are made with respect to a system in which the surfaces which are heated are at a sufficiently high temperature so that water vapor does not condense. In other words, no part of the new result is due to condensation of water vapor on cooler surfaces. In the case of the application to an IC engine, not only are the surfaces hot but the exhaust gases leave the engine cylinder greatly above the condensation point of water vapor.

In the IC engine modification of the present invention, while the total amount of power may be as great or, under certain circumstances, even greater, the peak flame temperature is usually lower, and it seems probable that the reduced emission of NOx results primarily from this factor. However, this is not known, and the water vapor present in larger amounts as compared to carbon dioxide may also play a part. Therefore, it is not intended to limit the invention to any particular theory, and the above statements are made because I think the factors mentioned are at least some, and conceivably the only, factors involved.

The invention is not limited to the time in the whole operation when the very fine water-in-oil emulsion is actually produced. This may be at the point where atomization takes place just prior or at the point of ignition. This, however, is not necessary, and the emulsion may be performed and conveyed to the burner nozzle in a preformed state. Particularly with the referred emulsions obtained by sonic agitation, the emulsion is quite stable and so it can be produced at a point remote from the actual burner itself, and such a modification is of course included. It is also possible to have the emulsion formed by flowing water and oil over the emulsifying point, so that the emulsion is formed at the same place, or practically at the same place, as atomization into the flame takes place. In the case of the use of sonic atomization, particularly for IC engine use, it is almost always preferable to have the streams of water and fuel unite just prior to the point of atomization. It is possible, of course, to feed to the sonic atomizer an already formed emulsion, but this requires a separate step and the results are not significantly better. Therefore, particularly in the case of sonic atomization for combustion, and even more particularly in the case of IC engines, it is generally preferred to have the emulsion formed at the point and as a part of the atomization or atomizing device.

It is an important advantage of the present invention that it is not necessary to use any emulsifying agent, particularly when sonic emulsification is used. This eliminates the added step and, therefore, cost of the emulsion is reduced, although in a broader aspect the present invention does not exclude an emulsion which has been made in the presence of a small amount of an emulsifying agent, such as a small amount, usually a fraction of a percent, of a dialkyl sulfosuccinate or other well known emulsifying agent capable of facilitating the formation of water-in-oil emulsions. The invention in this aspect, which is normally not preferred, may use any known emulsifying agent.

Ordinarily more problems are presented with the burning of heavy residual fuel oil, and this frequently requires steam heating. In the case of the present invention, however, the heavy oil emulsifies more readily than light oil, and when emulsified with a considerable amount of water, the viscosity is low enough so that it can be burned without preheating. This is an additional advantage for use with heavier oils. Why the heavy oil emulsifies more readily and to a lower viscosity has not been fully determined. It is possible that the heavy fuel oil contains contaminants which aid in the emulsification which are not present in the purer lighter fuel oils. It is not intended, however, to limit the present invention to any theory of action.

While, as has been stated, the invention is not limited to any particular method, sonic emulsification is greatly preferred. It produces emulsions of maximum fineness at very low costs, and so in one further aspect of the invention there is included the combination of forming ultrasonically a fine water-in-oil emulsion and then introducing this into a burner.

Brief Description of the Drawings

Figure 1 shows, in diagrammatic form, a sonic emulsifier and burner;

Figure 2 is a detail on a somewhat enlarged scale, partly in section, of the emulsifier;

Figure 3 is a semi-diagrammatic illustration of a combined sonic atomizer and emulsifier, especially useful with internal combustion engines;

Figure 4 is an illustration of a unitary emulsifier and furnace burner, particularly for larger units, and

Figure 5 is a horizontal elevation detail of the expanded plate at the end of the probe.

Description of the Preferred Embodiments

In Figure 1 a sonic generator 1 is shown powering a sonic probe 2 in the form of an acoustic transformer, the end 9 of which extends into a chamber 3 through a flexible seal 4 located substantially at a nodal point of the sonic probe. A stream of fuel, such as house heating fuel oil, is introduced through a conduit 5 and a stream of water joins it through a conduit 7 with a fail safe valve 18 opened by fuel pressure. These two streams strike the vibrating end 9 of the sonic probe, as can best be seen in Figure 2 where a portion of the chamber 3 is shown in section. The violent sonic agitation emulsifies the two streams, which then leave axially through an outlet conduit 6 in a plate 10 which is located closely adjacent to the vibrating end 9 of the sonic probe. Fro the outlet conduit 6 the emulsion passes into a convenient burner 8 in a combustion chamber (not shown). Air is introduced at 20 and a flame results. While the proportion of fuel and water can vary over a wide range, for example fro about 10 % water to about 50 % water, a very suitable mixture is about 70 % fuel and 30 % water.

The sonic probe 2 is of conventional design with a stack of piezoelectric plates (not shown), which are energized through cable 12 by a suitable high frequency oscillator (not shown), which may operate, for example, at a frequency of approximately 20,000 Hz. The plate 9 at the end of the sonic probe 2 may be a flat plate or it may also be provided with a suitable baffle, for example a spiral baffle, to extend the period of residence in the violent agitation field. The sonic generator illustrated diagrammatically is of common a commercial type sold by the Branson Instruments under their trade name Sonifier. The particular design of the sonic emulsifier ahs nothing to do with the present invention and the illustration shows merely a typical one.

Figures 4 and 5 illustrate a unitary emulsifier and burner for furnace use. The same elements are given the same reference numbers as in Figures 1 to 3. The end of the Sonifier tip if of the general shape shown in Figure 3m which will be described further below, and the parts bear the same reference numbers there as in Figure 3. It will be seen tha in Figure 4 there is an overall housing through which a blast of air passes from the blower 13. This air flows over the ultrasonic generator, thus cooling it, which is desirable in a large sized burner, and finally passes over the end of the housing 15. The fuel and water streams flow into an annular space between the housing 15 and the Sonifier probe. The latter is provided with an end plate 10 which has a series of small annular depressions 11 with a central projection 12 forming the inside of the annulus. This can be seen in Figure 5. The clearance between the end of the housing and the plate 10 is quite narrow and is shown somewhat exaggerated in Figure 4 for the sake of clarity. A film of fuel and water flows over the plate, where it is emulsified and atomized and thrown some distance to the right, forming a flame, which is diagrammatically shown at 19.

Combustion results in a boiler were measured in relative times to bring the water in the boiler jacket from a particular temperature to a temperature just below its boiling point. The test accurately measures the relative heating efficiencies and is shown in the following table, which illustrates the results of 8 tests, test 1 to 5 being with straight No. 2 domestic heating oil and tests 6, 7, and 8 with a mixture of 70% oil and 30% water.

Temperature (1) ~ Temperature (2) ~ Time (min) ~ Material
1. 150 ~ 192 ~  --   ~ Oil
2. 150 ~ 194 ~ 4-13 ~ "
3. 146 ~ 194 ~ 4-14 ~ "
4. 144 ~ 192 ~ 4-6 ~ "
5. 144 ~ 194 ~ 3-40 ~ "
6. 146 ~ 194 ~ 3-30 ~ 600 oil/325 water
7. 144 ~ 192 ~ 4-20 ~ 850 oil/200 water
8. 144 ~ 196 ~ 4-16 ~ 800 oil/250 water

Boiler surfaces were carefully examined in the tests and were clean. A flame was produced which was whiter; there was no visible smoke from the chimney, and stack gas analysis showed a more complete and perfect combustion.

Figure 3 illustrates a modification particularly useful for IC engines. The Sonifier with its probe carry the same reference numerals as in Figures 1 and 2, but, as in Figures 4 and 5, the shape of the end of the probe is a little different, being expanded out into a plate 10. The plate is flat instead of provided with annular depressions as in figure 4. Gasoline was introduced through the conduit 14 into an annular space between the probe and a housing 15, and water was introduced through conduit 13. The two liquids flow down until they come to the edge of the expanded plate 10, where they proceed to flow along the top of the plate and are atomized and emulsified at the same time. Air is introduced adjacent the atomized emulsion through an air conduit 16 and the resulting mixture is fed into the manifold of an internal combustion engine (not shown).

The plate 10 projects beyond the housing, the clearance between housing and Sonifier being exaggerated as in Figure 4, and the violent sonic agitation of the pate throws a finely divided emulsion up from the upper surface of its projection. As Figure 3 is designed to connect with a manifold of an IC engine, there will usually be a certain amount of vacuum, and this causes the emulsion to be pulled around the edge pf the plate, as is shown by the arrows. Thorough mixing of the air takes place, but it is not necessary that the emulsion be thrown by sonic vibration into the manifold, whereas in Figure 4 with the horizontal burner this is necessary so that the fine emulsion atomized in the blast of air moves horizontally to form the burner flame. It is for this reason that the actual contact of the plate with the film of fuel and water flowing over it is on its forward face so that it will be thrown in the direction to form the burner flame, for of course in an ordinary burner there is not the vacuum which exists in an internal combustion engine manifold.

Figures 3 and 4 and 5 illustrate different forms of Sonifier and emulsion forming plate, but the invention is not limited to the exact shapes shown nor for that matter to the flat tip face as shown in Figure 2. These are simply illustrations of typical configurations, but the invention is not limited to the details thereof.

The IC engine fed with a gasoline and water emulsion atomized into the air ran with the same power as on straight gasoline, and pollutants were reduced, unburned hydrocarbons practically zero, and NOx still more reduced. The figures illustrate the pollutant concentrations, the engine running at about 5000 rpm under load. It will be noted that the pollutant concentrations are far below present emission standards and even meet more rigid standards proposed for later years. Carbon monoxide 0.94, unburned HC 0.0, NOx 11.35 ppm.

I claim: [ Claims not included here ]



US Patent # 3,941,552

( US Cl. 431/1 ~ March 2, 1976 )

Burning Water-in-Oil Emulsion Containing Pulverized Coal

Eric C. Cottell

Abstract --- Pulverized coal is slurried with water then oil or if desired oil and pulverized alkalis preferably lime or limestone is added and the mixture subjected to sonic vibrations with an energy density of at least 11.625 watts per cm.sup.2. Liquid suspension is produced and any excess water or oil separates out as a separate phase. Normally excess oil is used and the excess oil phase can be recycled. The resulting dispersion is utilized and burned in a furnace. A clean flame is produced which has the characteristics of an oil flame and not a powdered coal flame. The addition of lime is optional as its purpose is to reduce sulfur dioxide in burning where the coal contains sulfur. If there is no sulfur or so little as to meet environmental standards the addition of lime may be omitted. The amount of lime is preferably at least about twice stoichiometric based on the sulfur content of the coal. Up to 80% of sulfur dioxide produced on burning can react with the lime and the calcium sulfate produced removed by conventional particle separators.

References Cited
U.S. Patent Documents
3073652 ~ Jan., 1963 ~ Reichl ~ 110/7
3746257 ~ Jul., 1973 ~ Broad, et al. ~ 239/102
3823676 ~ Jul., 1974 ~ Cook, et al. ~ 110/1

Primary Examiner: Favors; Edward G.
Attorney, Agent or Firm: Norton; Robert Ames, Leitner; Saul

Description

BACKGROUND OF THE INVENTION

Coal is usually burned either in a bed or if pulverized and atomized in the form of fine particles. When the coal contains substantial amounts of sulfur this is transformed into oxides of sulfur, mostly sulfur dioxide, during combustion. Sulfur oxides constitute serious atmospheric pollutants and in recent years quite stringent standards have been set in the United States for the concentration of sulfur oxides which can be vented to the atmosphere. This has required either low sulfur coal, about 1% or less, or the coal can be treated to remove excessive sulfur. In either case, there is a substantial penalty. It has therefore been proposed to mix finely divided lime or limestone with the coal and during burning a considerable amount of sulfur dioxide is oxidized in the combustion process which always has excess oxygen and calcium sulfate is produced. The removal of the particulate calcium sulfate can be effected by conventional means such as electrostatic precipitation. Combustion is not as complete as could be desired and unless there is a very large excess of lime the amount of sulfur oxides removed can be insufficient in the case of high sulfur coals.

It is with an improved coal fuel that the present invention deals and problems such as explosion hazards in powdered coal plants that are not kept scrupulously clean are avoided.

SUMMARY OF THE INVENTION

In the present invention pulverized coal is used particle sizes below 100.mu. and a considerable portion is normally much finer down to as fine as 1.mu.. This is approximately the same form of coal used for powdered coal burning. When the tiny coal particles are examined under a microscope the surface appears quite porous. The pulverized coal is slurried with water and then oil is added, such as ordinary heating oil and the slurry is then subjected to violent sonic agitation. Ordinarily the frequency is in the ultrasonic range, for example from 20,000-30,000 Hz., or even higher frequencies. While in practice frequently ultrasonic agitation is used high sonic frequency for example 15,000-20,000 Hz. can be used, therefore throughout this specification the generic term "sonic" is used which covers both audible and ultrasonic frequencies. It should be realized that intense agitation which produces strong cavitation is necessary and this is measured as intensity and not as power. In the present invention the intensity should be at least 11.625 watts per cm.sup.2. Commonly intensities of around 38.75 to 54.25 watts per cm.sup.2 or a little less are employed. While there is a definite lower limit for sonic intensity below which satisfactory fuels will not be produced, there is no sharp upper limit. However there is no significant improvement above 54.25 watts per cm.sup.2 and higher intensities add to the cost of producing the fuel without resulting improvement. In other words, the upper limit is not a sharp physical limit but is dictated by economics.

So long as the energy density meets the specifications above, it does not make much difference how the sonic energy is produced and the present invention is not limited to any particular apparatus. A very practical sonic generator is a so called sonic or ultrasonic probe. Longitudinal vibrations are produced as conventional, either by piezoelectric, magnetostrictive device or the like. The sonic generator proper is then coupled to a solid velocity transformer, sometimes called an acoustic transformer, which tapers down, preferably exponentially, ending in a surface of much smaller area than that coupled to the sonic generator. In accordance with the law of conservation of energy the distribution of the vibrations over the smaller surface requires that the surface move more rapidly. This results in a much greater energy density andd as the total power is being transformed from a larger area to a smaller area, this is referred to as a transformer by analogy with electrical transformers which can step up voltage. Sonic probes of the type described above are commercial products and sold, for example by Branson Instruments under their trade name of "Sonifier." This type of apparatus for producing high sonic energy density, which should not be confused with sonic power, is a very economical and satisfactory type of producing the necessary sonic energy intensity. In a more specific aspect of the present invention the use of this type of instrument is included but of course the exact way the vibrating surface is energized is not what distinguishes the present invention broadly from the prior art.

The high intensity sonic agitation appears to drive water into the pores of the porous coal particles and then produces a water-in-oil type of emulsion. This is not a true emulsion because it includes suspension of the tiny coal particles as well as a dispersion of oil and water. However, the behavior of the resulting product which is a somewhat viscous liquid is not that of a typical emulsion. In a typical water-in-oil emulsion, the continuous oil phase can be diluted with more oil to produce a more dilute emulsion. In the case of the present invention, however, when an excess of oil is used oil separates as a separate phase, in this case a supernatant phase. While it is theoretically possible with an exact ratio of coal, water and oil to produce a product that does not separate out any oil phase as a practical matter this is undesirable because the separation it too critical and it is much better to operate with a small excess of oil and separate and recycle the supernatant phase. Although, as has been pointed out above, the product of the present invention is not technically a water-in-oil emulsion it has some properties that are similar. Thus, for example, after removing a supernatant oil phase the remaining oil and water remains stable in and around the coal particles and the product can be stored for a reasonable time without further separation of the components. For this reason the product will be referred to in the specification as an emulsion even though technically it is not a true emulsion. It is, however, a dispersion of the coal particles and tiny water droplets and, as pointed out above, it is stable. When the product or fuel of the present invention is burned it burns very cleanly with a flame of the color and characteristics of an oil flame rather than a powdered coal flame. Apparently during combustions there is not a physical production of fine coal particles although the exact mechanism of combustion has not been completely determined and the present invention is therefore not intended to be limited to any particular theory.

The exact proportion of coal, water and oil is not critical, which is an advantage. It will vary a little with the gravity of the oil and with particular coal an excellent practical ratio is about 20 parts of pulverized coal, 15 parts of oil and 10 parts of water. This product settles out only a little oil as a supernatant liquid and a very stable dispersion results. However, somewhat more oil may be used and in some cases is desirable because the separated oil phase can easily be recycled, and therefore the above ratio of ingredients is illustrative of a typical useful product. It should be noted that if there is an excess of water this also can separate a portion of water as a separate phase. For practical operation it is usually desirable to have any excess in the form of oil.

The violent sonic agitation also performs an additional function. It reduces the particle size of the coal, possibly because of coal particles striking each other during the violent agitation. The exact amount of reduction of particle size depends both on the energy density of the sonic agitation and on the character of the particle coal. A more fragile coal will, of course, be reduced somewhat more but the final size range still remains between about 1.mu. and about 100.mu..

While the dispersion is fairly viscous it still flows readily and does not have to be heated prior to supplying it to the burner. This is an advantage over burning highly viscous residual fuel oils which have to be heated by steam before being atomized in a burner. This is one of the advantages of the present invention as it permits eliminating heating equipment without eliminating its function.

The actual atomization in a burner is not what distinguishes the present invention from the prior art and any suitable form of a burner can be used. One such form is a sonic probe which atomizes the dispersion of fuel from its end.

Where the coal used is of low sulfur so that sulfur oxide emissions from a furnace stack are within environmental standards the fuel of the present invention may constitute only pulverized coal, oil and water, however, the present invention makes possible elimination of a large amount of sulfur oxides in a very simple and economical manner. This opens up cheap, high sulfur coal for use where it would otherwise not meet environmental standards. When it is desired to reduce sulfur oxide emissions preferably finely pulverized lime or limestone may be dispersed in the water. This will be generally referred to as lime and it may be introduced in the process of the present invention either before or after oil introduction, preferably it is introduced substantially simultaneously when feeding to the sonic emulsifier. It should be noted ordinarily pulverized lime will be fed in in the form of a water slurry and the water content must be taken into consideration in the total amounts of water in the final product. When the pulverized lime is introduced it forms part of the suspension and is stable and does not settle out on standing. This avoids any distinct problems and is a further advantage of the aspect of the present invention where sulfur oxides are decreased.

Lime is the preferred alkali to use when high sulfur coal is to be burned. It has many practical advantages such as low cost and the fact that the calcium sulfate which is produced in the flame has very low solubility in water. Other alkalis may be used such as for example sodium carbonate. Most of these other alkalis form sulfates which have considerable solubility in water. As water vapor is always produced in the burning of the fuel this can present problems particularly as at some stage of the stack gas treatment temperatures are reduced and liquid water may condense out. In such a case it can form somewhat pasty masses with alkalis, the sulfates of which are fairly soluble in water. This makes electrostatic precipitation more difficult, as the precipitator normally requires that the particles which it removes be dry. There is also a possibility in other parts of the combustion gas treatment equipment for deposition of pasty sulfates to result. This requires additional cost for cleaning and is one of the reasons why lime is the preferred alkali. However, other alkalis may be used and in its broadest aspect the invention is not limited to the use of lime although this is the preferred material.

The removal of sulfur oxides depends on the amount of lime or other alkali. The lime should normally be in excess over the stoichiometric value based on the sulfur content of the coal. The more lime used the greater reduction. For example with a 50% excess 50% of the sulfur oxides may be eliminated or rather fixed as calcium sulfate. When more lime is used the sulfur oxide reduction becomes greater reaching about 80% when the lime is in twice stoichiometric ratio. The additional removal of sulfur with still more lime occurs more slowly as the curve tends to asymptote and therefore ordinarily much greater excesses than twice stoichiometric are not economically worthwhile. With quite high sulfur coal the the approximate 80% reduction brings the fuel within environmental standards. Lime, while not a very expensive material still adds to the cost and in some cases with lower sulfur coals a 50% sulfur oxide removal brings the fuel within environmental standards and in such cases smaller excesses of lime may be used. This is an economic question and there is no sharp upper limit. Theoretically calcium sulfate (gypsum) which is recovered by electrostatic precipitation or other means can be sold. However, the cost of producing the recovered gypsum may be more than its sale price so, where unneeded for environmental purposes, smaller lime excesses can present an economical advantage and are of course included.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagrammatic showing of an experimental furnace burning the coal dispersion in a bed;

FIG. 2 is a curve showing SO.sub.2 removal for various amounts of lime up to 50% excesses;

FIG. 3 is a diagrammatic flow sheet of a practical installation atomizing the coal dispersion to form a flame.

FIG. 4 is a semi-diagrammatic illustration of an ultrasonic probe.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIGS. 1 and 2 deal with an experimental set up in which the coal dispersion is burned in a bed. The coal dispersion is typically produced by dispersing 20 parts of coal in 10 parts of water adding 15 parts of oil, such as No. 2 heating oil, and subjecting the product to violent ultrasonic agitation with an energy density of between 38.75 to 54.25 watts per cm.sup.2. In order to permit rapid dispersion the thickness of the liquids in contact with the vibrating surface is of significance, for example, in an ultrasonic probe which will be described in combination with FIG. 4. The thickness of the liquid layer is not sharply critical, but should be normally considerably less than the diameter of the vibrating surface. If the thickness of liquid becomes much greater the output is reduced although if sufficient time is given a satisfactory dispersion can be produced in quite a thick liquid layer, however, this is economically undesirable. Obviously, of course, the thickness of the layer of the suspension between the vibrating surface and container must be greater than the dimensions of the largest coal particles. As has been stated above, the particular size range is from about 1.mu. to about 100.mu.. Although it is not practical to get an exact measurement the dispersion appears to be fairly uniform.

The present invention is not limited to any particular finely divided coal. Typical coals in the specific embodiments to be described are an eastern bituminous coal having from 1 to 2% of sulfur. Another typical coal is a western Kentucky coal having slightly more sulfur.

To produce a coal dispersion which will reduce sulfur oxide production on combustion pulverized lime in a water slurry is introduced at about the same time as the oil. The water in this slurry must of course be taken into consideration for the water proportion. If the coal is very low sulfur a lime excess of around 50% of stoichiometric can be used. For higher sulfur coals, for which the present invention is particularly advantageous, the excess should be about twice stoichiometric.

Turning back to FIG. 1 the experimental furnace is shown at (1) and is preheated electrically as is shown by the wires going to a surrounding electrical heating jacket. In the experimental set up the furnace was a cylindrical furnace about 1.25 inches in diameter. The coal dispersion is introduced and forms a bed on a suitable burning grate (2). Air is introduced as is shown and the amount of air should be approximately that corresponding to most economical combustion, i.e. a slight excess of air. The gases from the burning bed pass into a sidearm testube (3) which is filled with glass wool. This removes some solids and other impurities and then passes into a water scrubber (4) which in the experimental set up contains water with about 3% hydrogen peroxide. Then the gases pass on to a trap (5) and to a water trap (6) both in the form of sidearm flasks, the latter containing glass wool. The gases are pulled through by a partial vacuum as indicated on the drawing from any source, (not shown). Flow is measured by a rotameter (7).

Results of the tests are shown in the following table 1:

                                      TABLE 1
    __________________________________________________________________________
    Removal of SO.sub.2 by Limestone in coal-oil-water suspension
    __________________________________________________________________________
    Run No.
          Type of                   Fuel 16N NaOH
          Burn (Grams)
                    Oil  H.sub.2 O
                              Limestone
                                    Burnt
                                         (SO.sub.2 titrate)
                                                 SO.sub.2
                    (Grams)
                         (Grams)
                              (Grams)
                                    Grams
                                         ml      removal %
    __________________________________________________________________________
    1     Bed  20   20    5   0     9.5  6.3     0
               20   20    5   .48   10.0 4.4     33
               20   20   10   0     8    7       0
    2     Bed  20   20   10   .48   7    4.5     26
    3     Bed  20   20   10   0     10   9       0
               20   20   10   1.5   10   4.9     44
    4     Bed  20   20   10   0     6    4.8     0
               20   20   10   1.5   6    2.4     50
    5     Atomized
               20   15   10   0     6.9  2.5     0
          Fuel 20   15   10   1.5   16   3.0     50
          Spray
    __________________________________________________________________________

It will be seen that Table 1 includes a number of tests made with varying amounts of oil and water and in each case included no finely divided lime or the number given in the table 1. This table also gives the amount of fuel burnt and sulfur oxides were measured by titrating with a sodium hydroxide solution.

The first four runs were burned in a bed, the fifth run atomized the fuel from the end of an ultrasonic probe. The sulfur oxide removal versus lime is shown as a graph up to 50% excess in FIG. 2. When the excess becomes greater than twice stoichiometric the curve flattens out or asymptotes at about 80% removal. In other words, in such a range the curve is actually an S. Curve.

FIG. 3 is a diagrammatic illustration of a practical flow sheet for a large plant. In this case the combustion is by atomizing the fuel from an ultrasonic probe. Coal, as shown on the drawing, is pulverized in a ball mill and pulverizer (8) and reduced to a particle size of less than 100.mu., with some of the particles as small as 1.mu.. The coal is then fed by a vibro-feeder (9) into a stream of water flowing at a controlled rate into a slurry tank (10). Slurrying is effected by a conventional propeller, a vent to the air providing deaeration. The slurry then passes through a controller and oil controlled by controller (11) is introduced and a little further on a lime slurry passes through in the controller (11). The proportion of lime to sulfur in the coal is about twice stoichiometric.

The slurry is then premixed in a premixer (16). The premixed slurry is then introduced into a sonic disperser (13) in this disperser an ultrasonic probe operating at between 20,000-22,000 Hz of the type shown in FIG. 4 which will be described below and the end of the probe which is operated from the front of the container (13) to produce a thickness of liquid substantially less than the cross sectional dimension of the end of the probe. Violent sonic agitation with cavitation resulted in the energy intensity being about 38.75 to 54.25 watts per cm2. A stable dispersion is produced which flows into a separator (14) provided with a weir (15) this weir permits some supernatant oil to flow over into a compartment from which the recycling line (16) recycles it to the premixer (12).

The coal-water-oil-lime then flows into another ultrasonic probe housing (17) and is atomized from the end of the ultrasonic probe into a combustion chamber (18). It is burned and the flue gases pass through a particulate separator in the form of an electrostatic precipitator (19) this removes finely divided calcium sulfate which can be recovered and sold. With coal having 2-3% sulfur the removal of sulfur dioxide is about 80% which brings the flue gases to environmental standards.

FIG. 4 is a semi-diagrammatic showing of a typical ultrasonic probe (20). Ultrasonic vibrations from 20,000-22,000 Hz result from electricity at the same frequency which is shown coming in through wires. The vibration is in a piezo-electric stack (21) to which is coupled the broad end (22) of a steel velocity transformer which tapers exponentially to a small end (23). It is this end which agitates the dispersion in the agitator (18) on FIG. 3 and a similar probe produces atomization as indicated at (17) in FIG. 3.

Combustion of the atomized fuel produces a flame which is clear and results in complete combustion and which does not have the appearance of a flame from pulverized coal combustion. The presence of water in the fuel dispersion is probably what assures the flamequality and which permits very complete combustion. The combustion is so complete that there is very little if any loss in heating due to the presence of water which, of course, is flashed into steam as the dispersion burns.



US Patent # 4,048,963

( US Cl. 123/25R ~ September 20, 1977 )

Combustion Method Comprising Burning an Intimate Emulsion of Fuel and Water

Eric C . Cottell

Abstract --- A combustion process in which a water-in-oil emulsion of liquid fuel, such as liquid hydrocarbons, containing from 10 to 50% water and preferably 10 to 30% water is burned. The emulsion is produced, with little or no added emulsifying agent, by sonic agitation, including a sonic generator and an acoustic transformer having a larger cross-section coupled to or in contact with the sonic generator than at its other end, at which emulsification takes place, whereby the sonic energy density is increased. With the increased sonic density an emulsion is produced which when burned produces a quality of burn such that the combustion is faster, more complete, and cleaner, with an increase in efficiency even up to 30% of water. The increase in efficiency often equals that obtained by the burning of the same weight of pure fuel in the conventional manner.

References Cited
U.S. Patent Documents
2704535 - 2947886 - 2949900 - 3070313 - 3145931 - 3200873 - 3374953 - 3606868 - 3658302

Parent Case Text

RELATED APPLICATIONS

This application is a continuation-in-part of my earlier application Ser. No. 489,710, filed July 18, 1974, which application in turn was a continuation-in-part of my application Ser. No. 280,967, filed Aug. 16, 1972, and which was a division of my application Ser. No. 122,632, filed Mar. 1, 1971, which is now U.S. Pat. No. 3,749,318, July 31, 1973. All of the earlier applications above referred to except Ser. No. 122,632 are now abandoned.

Description

BACKGROUND OF THE INVENTION

The combustion of liquid fuel, such as liquid hydrocarbons, is a standard method of power and/or heat generation. The combustion may be in a system where the heat is transferred to another medium, such as water, with or without boiling the water, or the fuel may be burned in various types of internal combustion engines, such as those operating on Otto, diesel, or other cycle. The amount of oxygen, usually air, is at least about theoretically sufficient for complete combustion of the fuel elements.

Considerable problems have arisen. If there is a very large excess of oxygen, the efficiency of the combustion process is lowered because a considerable amount of air, including inert nitrogen, has to be heated up. In the case of an internal combustion engine also operating with excessive excesses of oxygen can result in slow combustion, which can overheat and burn out exhaust valves. If the combustion is with amounts of oxygen and fuel more nearly in balance, for example with only a small excess of oxygen, problems arise with incomplete combustion. This can result in excessive amounts of carbon monoxide and/or incompletely burned fuel, which may show up as unburned hydrocarbons, soot, and the like. Incomplete combustion lowers the combustion efficiency and can also contaminate the equipment. In the case of internal combustion engines, unburned hydrocarbons, carbon monoxide, and oxides of nitrogen, generally symbolized by the formula NO.sub.x, are serious atmospheric pollutants as they give rise to photochemical smog and the like. Contamination of nitrogen oxides from an internal combustion engine usually results when combustion temperature is high.

It has been proposed in the past to introduce streams of water into a burner or to inject water into an internal combustion engine as it operates. This has proven to reduce somewhat incompletely burned fuel desposited in the form of carbon, and in the case of internal combustion engines this can lower nitrogen oxide production and also in certain cases, such as aircraft piston engines, permit operating for short times at higher power outputs with very rich mixtures which would otherwise burn up the engine. Water injection, however, has serious drawbacks.

Problems have arisen in the control of relative amounts of water and fuel precisely, and even if the control is maintained to a satisfactory degree, efficiency drops because the water has to be vaporized.

It has also been proposed to produce an emulsion of hydrocarbon fuel and water by sonic vibration and then to burn this emulsion in a burner. This is described, for example, in the U.S. Pat. to Duthion, No. 3,658,302, Apr. 25, 1972. The Duthion patent utilizes a form of sonic agitation produced by impinging a jet of the liquids against the edge of a blade free to vibrate. This form of sonic device is known in the art as a liquid whistle and was developed by the inventor of the present application, whose earliest U.S. Pat. is No. 2,657,032, Oct. 1953. While the emulsion produced is capable, in some cases, of being burned in a burner, particularly when a considerable amount of surfactant is added, it does not burn completely and produces an amount of heat which is usually less than that obtained by burning the fuel content because with the poor quality of emulsion the heat required to vaporize the water reduces the efficiency.

The present invention deals with an improved water-in-oil emulsion with which much higher efficiency is produced.

SUMMARY OF THE INVENTION

The present invention burns a sonically emulsified, extremely fine water-in-oil emulsion, normally of hydrocarbonaceous fuel, in which the water droplets are of extremely fine particle size. The emulsion is effected by sonic generator coupled to an acoustic transformer, with a larger cross-section coupled to or in contact with the sonic generator than at its other end where the emulsion of the present invention is produced. Because the sonic energy is distributed over a much smaller area, the energy density is greatly increased. Since the sonic generator is operated at a fixed, predetermined frequency, the transformation in the transformer causes the velocity of movement and also its path length at the small end to be increased in order to comply with the law of conservation of energy. For this reason the acoustic transformers of the type described above are often referred to in the art as velocity transformers and the two terms are synonymous. The small end of the acoustic transformer emulsifies fuel and water in a restricted space through which the two liquids flow. Energy densities of about an order of magnitude greater than those obtainable in the liquid whistle type of sonic agitator are readily obtained and produce an emulsion which is not only burnable but which when burned produces combustion efficiency such that the yield of useful heat, from say a conventional boiler, is almost the same as if pure oil had been burned. Therefore, improvements in efficiency of 10% to 30% are not uncommon. When used in an internal combustion engine, flame temperature is decreased but the total amount of power produced by the engine is as great as by burning a comparable amount of unemulsified fuel. The invention is not limited in its broadest aspect to a water content of from 10% to 30% water as emulsions having up to 50% water are still burnable though they do not produce as much heat as would be obtained by burning the same total quantity of unemulsified fuel. As is well known, acoustically it makes no difference whether the acoustic or velocity transformer has its large end in contact with the sonic generator or whether it is coupled to the sonic generator, for example through a resonant metal bar. In the claims the term "coupling" or "coupled" is used generically wherever the sonic energy is transmitted, substantially without loss, from the sonic generator to the large end of the transformer and is not limited to actual physical contact of the large end with the vibrating crystals or other elements of the sonic generator or through a coupling element.

The water content is not critical within its range, optimum results being obtainable with about 30% of water in an ordinary burner and less when the emulsion is used in an internal combustion engine; for example, optimum results are obtainable with about 18% to 20% water. In every case very clean combustion takes place, minimizing contamination and pollution, and in an internal combustion engine emission controls are readily met.

The surprising result of obtaining as much heat from an emulsion as with unemulsified fuel has been repeatedly tested. While I do not want to limit the present invention to any particular theory of why this suprising result takes place, it seems probable that the combustion of the emulsion in which the microscopic water globules explode into steam is more complete. The surfaces of a furnace or boiler encountering the flame may be below the condensation point of water or above, the latter being more common unless hot water at fairly low temperature is to be produced. In the case of an internal combustion engine temperature, the inner surfaces of the cylinder and the top of the piston are always above the condensation point of water when the engine is operating. The tests made and described in a later portion of the specification were with furnaces and engines where the surfaces were at a temperature higher than the condensation temperature of water, and therefore the improved results do not depend on the condensation of water vapor on cooler surfaces.

I also do not want to limit the invention to any particular theory of why the optimum water contents are somewhat lower for an internal combustion engine than for a burner in an ordinary heating furnace. A possible explanation might be that the heating oils have an average boiling point above that of water and, therefore, in the flame are completely exploded into steam without significant vaporization of the hydrocarbon fuel. In the case of gasoline used in the internal combustion engine tests, which will be described below, the average boiling point of gasoline is lower than that of water, and therefore it is possible that there may be some vaporization of gasoline during combustion before all of the water has been flashed into steam. There has been no rigorous proof of the above explanations but they are plausible possibilities and may well be part or all of the explanations of the surprising results obtained by the present invention.

In the internal combustion engine modification of the present invention, while the total amount of power may be as great or, under certain circumstances, even greater, the peak flame temperature is usually lower, and it seems probable that the reduced emission of nitrogen oxide results primarily from this factor. However, this is not known, and the water vapor present in larger amounts as compared to carbon dioxide may also play a part. Therefore, it is not intended to limit the invention to any particular theory, and the above statements are made because I think the factors mentioned are at least some, and conceivably the only, factors involved.

The invention is not limited to the time in the whole operation when the very fine water-in-oil emulsion is actually produced. This may be at the point where atomization takes place just prior or at the point of ignition. This, however, is not necessary, and the emulsion may be preformed and conveyed to the burner nozzle in a preformed state. The emulsions obtained by sonic agitation including the acoustic transformer are quite stable and so they can be produced at a point remote from the actual burner itself, and such a modification is, of course, included. It is also possible to have the emulsion formed by flowing water and oil over the emulsifying point, preferably the end of a sonic probe, so that the emulsion is formed at the same place, or practically at the same place, as atomization into the flame takes place. In the case of the use of sonic atomization, particularly for internal combustion engine use, which is described and claimed in my co-pending application, U.S. Pat. No. 3,756,575, issued Sept. 4, 1973, referred to above, it is usually preferable to have the streams of water and fuel unite just prior to the point of atomization.

It is an important advantage of the present invention that it is not necessary to use any emulsifying agent, particularly when sonic emulsification is used. This eliminates the added step and, therefore, cost of the emulsion is reduced, although in a broader aspect the present invention does not exclude an emulsion which has been made in the presence of a small amount of an emulsifying agent, such as a small amount, usually a fraction of a percent, of a dialkyl sulfosuccinate or other well known emulsifying agent capable of facilitating the formation of water-in-oil emulsions. The invention in this aspect, which is normally not preferred, may use any known emulsifying agent.

Ordinarily more problems are presented with the burning of heavy residual fuel oil, and this frequently requires steam heating. In the case of the present invention, however, the heavy oil emulsifies more readily than light oil, and when emulsified with a considerable amount of water, the viscosity is low enough so that it may be burned without preheating, or with less preheating, or at a lower temperature where cold water is added. This is an additional advantage for use with heavier oils. Why the heavy oil emulsifies more readily and to a lower viscosity has not been fully determined. It is possible that the heavy fuel oil contains contaminants which aid in the emulsification which are not present in the purer lighter fuel oils. It is not intended, however, to limit the present invention to any theory of action.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows, in diagrammatic form, a sonic emulsifier and a burner;

FIG. 2 is a detail on a somewhat enlarged scale, partly in section, of the emulsifier;

FIG. 3 is a semi-diagrammatic illustration of a combined sonic atomizer and emulsifier, especially useful with internal combustion engines, and

FIG. 4 is a cross-section through a modified form of sonic probe.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In FIG. 1 a sonic generator 1 is shown powering a sonic probe in the form of an acoustic transformer 2, the end 9 of which extends into a chamber 3 through a flexible seal 4 located substantially at a nodal point of the sonic probe. A stream of fuel, such as house heating fuel oil, is introduced through a conduit 5 and a stream of water joins it through a conduit 7 with a fail safe valve opened by fuel pressure. These two streams strike the vibrating end 9 of the sonic probe, as can best be seen in FIG. 2 where a portion of the chamber 3 is shown in section. The violent sonic agitation emulsifies the two streams, which then leave axially through an outlet conduit 6 in a plate 10 which is located closely adjacent to the vibrating end 9 of the sonic probe. From the outlet conduit 6 the emulsion passes into a conventional burner 8 in a combustion chamber, (not shown). Air is introduced at 26 and a flame results. While the proportions of fuel and water can vary over a wide range, for example from about 10% to about 50% water, a very suitable mixture is about 70% fuel and 30% water.

The sonic probe is of conventional design with a stack of piezoelectric plates, (not separately shown), which are energized through the cable 12 by a suitable high frequency oscillator, (not shown), which may operate, for example, at a frequency of approximately 20,000 HZ. The plate 9 at the end of the sonic probe 2 may be a flat plate or it may also be provided with a suitable baffle, for example a spiral baffle, to extend the period of residence in the violent sonic agitation field. The sonic generator illustrated diagrammatically is of a common commercial type sold by the Branson Instruments under their trade name "Sonifier." The particular design of the sonic emulsifier has nothing to do with the present invention and the illustration shows merely a typical one. The combination of the sonic generator and acoustic transformer is essential to produce the increased energy density on which the results of the present invention depend. However, the invention may use any other design having a sonic generator and an acoustic transformer producing comparable energy densities.

FIG. 4 illustrates a more recently developed Sonifier by Branson Instruments which has certain practical advantages, at least for larger burners. It is shown in cross-section. 1 is the generator, which is a stack of conventional piezoelectric crystals. These crystals are not of as large cross-section as the corresponding generator in FIGS. 1 and 2 because they are coupled to an acoustic transformer, which, as it performs the same function as the transformer in FIGS. 1 and 2, bears the same reference numeral 2. The coupling is through a half-wave resonant rod 17, which couples to the large end of the acoustic or velocity transformer 2. The large end is shown at 18, and the transformer can be clamped by the flange 25 where additional rigidity is desirable since the modified Sonifier is considerably longer in length than that shown in FIGS. 1 and 2. The small end 32 of the transformer is bolted to and therefore coupled to a rod 21 at the end of which there is the same kind of plate 19 as is shown in FIGS. 1 and 2. The rod is provided with lands 24 and elastomeric rings 23. This is the portion which is at an approximate quarter wavelength and which seals the container where the emulsion is produced. This container and associated elements are the same as in FIGS. 1 and 2. Therefore, they are not repeated in FIG. 4. The modified Sonifier has the advantage that it is not limited to a single size of acoustic transformer and can be used with transformers of various cross-sectional ratios. Also, it is provided with a clamping flange 25, as has been described, which permits much more rigid construction and makes it suitable for a longer probe. The operation is exactly the same. The vibrations produced by the vibrating crystals are coupled to the acoustic transformer 2 and the energy density is increased in the same way as by the transformer in FIGS. 1 and 2.

The equipment of FIGS. 1 to 4 produce the same increased energy density at the small end of the probe. It should be noted that this is energy density, i.e. violence of agitation, which is effected by longer paths, hence the alternative name of velocity transformer. It is energy density which is required in the present invention and not total power input. As has been stated earlier, the energy density is about an order of magnitude greater than can be produced in a liquid whistle, and in the probes of FIGS. 1 to 4, for illustration, this energy density is approximately 37 watts/cm.sup.2.

As illustrated and described above, stable fuel and water emulsions of the water-in-oil type are produced, and when these emulsions are burned combustion results in a boiler were measured in relative times to bring the water in the boiler jacket from a particular temperature to a temperature just below its boiling point. The test accurately measures the relative heating efficiencies and is shown in the following table, which illustrates the results of eight tests, tests 1 to 5 being with straight No. 2 domestic heating oil and tests 6, 7 and 8 with a mixture of oil and water.

    ______________________________________
    TEMPER-      TEMPER-
    ATURE (1)    ATURE (2)    TIME    MATERIAL
    ______________________________________
    1.  150     degrees  192   degrees      Oil
    2.  150     "        194   "      4-13" Oil
    3.  150     "        194   "      4-14  Oil
    4.  146     "        192   "      4-6   Oil
    5.  144     "        194   "      3-40  Oil
    6.  146     "        194   "      3-30  600 Oil
                                            325 Water
    7.  144     "        192   "      4-20  850 Oil
                                            200 Water
    8.  144     "        196   "      4-16  800 Oil
                                            250 Water
    ______________________________________

Boiler surfaces were carefully examined in the tests and were clean. A flame was produced which was whiter; there was no visible smoke from the chimney, and stack gas analysis showed a more complete and perfect combustion.

Tests were made comparing water-in-oil emulsions produced in a standard commercially available liquid whistle which is similar to the design described in the first Cottell U.S. Pat. No. 2,657,021, referred to above, with emulsions produced by emulsifiers used in the present invention and described in FIGS. 1 to 3. Liquid pressure in the liquid whistle was 200 psi and the energy density level in the sonic emulsifiers was approximately 37 watts/cm.sup.2 or about an order of magnitude greater than in the liquid whistle. The tests with various amounts of water and No. 2 heating oil were compared in two respects, one, stability, i.e. time for onset of emulsion inversion, and, two, flame characteristics.

    __________________________________________________________________________
    Water in Oil
            Liquid Whistle
                     Ultrasonic Fuel Reactor
                                  Remarks on   Remarks on
    Emulsion
            Time for Onset
                     Time for Onset of
                                  Combustion of Liquid
                                               Combustion of
    Water % of Inversion
                     Inversion    Whistle Emulsion
                                               Ultrasonic Fuel
    __________________________________________________________________________
     5%     5"       180"         Intermittent flame
                                               Bright, consistent
                                  Flame out in app. 8
                                               flame, no smoke
                                  sec. Smoke, possibly
                                  due to combustion
                                  failure
    10%     3"       150"         Intermittent flame
                                               Bright, consistent
                                  Flame out in app. 3
                                               flame, no smoke
                                  sec. Smoke, possibly
                                  due to combustion
                                  failure
    20%     5"       142"         Intermittent flame
                                               Bright, consistent
                                  Flame out in app. 2
                                               flame, no smoke
                                  sec. Smoke, possibly
                                  due to combustion
                                  failure
    30%     6"       140"         Intermittent flame
                                               Bright, consistent
                                  Flame out in app. 3
                                               flame, no smoke
                                  sec. Smoke, possibly
                                  due to combustion
                                  failure
    __________________________________________________________________________

It will be seen that at all water contents much more stable emulsions were produced in the ultrasonic fuel reactor of the present invention and the flame was excellent whereas emulsions from the liquid whistle produced intermittent flame accompanied by smoke, and in the operation flame out actually occurred.

FIG. 3 illustrates a modification particularly useful for internal combustion engines. The ultrasonic probe carries the same reference numerals as in FIGS. 1 and 2, but the shape of the end of the probe is a little different, being expanded out into a plate 10. Gasoline was introduced through the conduit 14 into an annular space between the probe and a housing 15, and water was introduced through conduit 13. The two liquids flow down until they come to the edge of the expanded plate 10, where they proceed to flow along the top of the plate and are atomized and emulsified at the same time. Air is introduced adjacent the atomized emulsion through an air conduit 16 and the resulting mixture is fed into the manifold of an internal combustion engine, (not shown).

The plate 10 projects beyond the housing, the clearance between housing and ultrasonic probe being exaggerated and the violent sonic agitation of the plate throws a finely divided emulsion up from the upper surfaces of its projection. As FIG. 3 is designed to connect with a manifold of an internal combustion engine, there will usually be a certain amount of vacuum, and this causes the emulsion to be pulled around the edge of the plate, as is shown by the arrows. Thorough mixing of the air takes place, but it is not necessary that the emulsion be thrown by sonic vibration into the manifold, whereas in FIG. 4 with the horizontal burner this is necessary so that the fine emulsion atomized in the blast of air moves horizontally to form the burner flame. It is for this reason that the actual contact of the plate with the film of fuel and water flowing over it is on its forward face so that it will be thrown in the direction to form the burner flame, for of course in an ordinary burner there is not the vacuum which exists in an internal combustion engine manifold.

The internal combustion engine fed with a gasoline and water emulsion atomized into the air ran with the same power as on straight gasoline, and pollutants were reduced, unburned hydrocarbons practically zero, carbon monoxide greatly reduced, and nitrogen oxides still more reduced. The figures illustrate the pollutant concentrations, the engine running at about 5,000 rpm under load. It will be noted that the pollutant concentrations are far below present emission standards and even meet more rigid standards proposed for later years. Carbon monoxide 0.94% unburned hydrocarbons 0.0, nitrogen oxides 11.35 ppm.



Cottell Patents @ Espacenet (European Patent Office)

Production of Fuel
Patent Number:   US4377391
Publication date:  1983-03-22
Inventor(s):  COTTELL ERIC C
IPC Classification:  C10L1/32; C10L9/00
EC Classification:  C10L1/32B

Abstract ~ The production of fuel comprising an emulsion of coal particles, oil and water or a dispersion of coal and oil in which pyrites, ash and other impurities are removed from the coal particles and the particles reduced in size by forming a slurry of contaminated coal particles and water and exposing that slurry to violent sonic agitation to cause the impurities to be detached from the coal particles and the particles to be reduced in size. The coal and impurities are thereafter separated and the coal subsequently incorporated into a fuel. The process may also be used to separate other minerals which are bonded mechanically as distinct from chemically, to each other.


Process for Beneficiating and Stabilizing Coal/Oil/Water Fuels
Patent Number:  US4326855
Publication date:  1982-04-27
Inventor(s):  COTTELL ERIC C
EC Classification:  B01J19/10, B03B9/00B, C10L1/32B
Equivalents:  BR8007307,  DK152808B, DK152808C, DK469080,  FI74727B,  FI74727C,  FI803330,  GR71927, ZA8006719

Abstract ~ A coal slurry containing 10-60% solids by weight is optionally first coarsely ground to about 20-80 mesh. Contaminant matter released thereby, may be separated by conventional means such as froth flotation which would eliminate a large proportion of the ash which is energy consuming as well as abrasive in nature. The "clean slurry" would now have water added back and would be further ground to about 100-300 mesh particle size and would then be cavitated by sonic energy making the particle size even smaller and freeing any remaining contaminants including iron pyrites and ash. To this, a mixture of oil is added and the coal, oil mixture is then sonified during which process spherical agglomeration of the coal and oil occurs. The agglomerate and water mixture is screened to separate out most of the water leaving behind about 10-40% water in the coal, during which process the contaminants are also discharged with the water. The spherical agglomerates are mixed with a balance of oil to about 0.6 times the weight of the coal to produce a stable thixatropic fuel with excellent pipe travel characteristics due to a migration of a thin film of water to the boundry layer between the bore of the pipe and the fuel. The process including the sonification steps is also useful generally in the separation of solids by agglomeration.


Fuel Supply System
Patent Number:  US4273078
Publication date:  1981-06-16
Inventor(s):  COTTELL ERIC C
IPC Classification:  F02M37/00
EC Classification:  F02M25/02B

Abstract ~ A fuel supply system comprises a supply tank with a main fuel conduit leading to a combustion zone, such as an internal combustion engine, and a secondary fuel conduit with flow restriction means is provided leading from the lowermost region of the tank to rejoin the main fuel conduit prior to the combustion zone so that any water accumulating in the tank is mixed with fuel to be burned at the combustion zone.



Production of Fuels
Patent Number:  US4218221
Publication date:  1980-08-19
Inventor(s):  COTTELL ERIC C
IPC Classification:  C10L1/32; B01F11/00
EC Classification:  C10L1/32D

Abstract ~ Apparatus and method for producing a fuel comprised of oil and water in which a mixture of oil and water is constituted as an emulsion by exposure to agitation effective to cause cavitation within the mixture.


DE 1053475 ~ No English title available.
GB 836439 ~ Improvements relating to the automatic regulation of the rate of flow of a fluid through a pipe or the like
GB 738773 ~ Improvements relating to the automatic regulation of the rate of flow of a fluid through a pipe or the like
GB 1013757 ~ Rotating liquid whistle
DE 2967000D ~ No English title available.
ES 8200717 ~ No English title available.
NO 823620 ~ No English title available.
NO 803369 ~ No English title available.
NO 793491 ~ No English title available.
IT 1209772 ~ No English title available.
IT 1124414 ~ Fuel supply for turbine or fuel injected IC engine
FI 803330 ~ No English title available.
US 5009197 ~ Method of removing oil from birds and animals
US 4412842 ~ Coal beneficiation process
US 4412512 ~ Fuel supply system
US 4400177 ~ Fuels and methods for their production
US 4377391 ~ Production of fuel
US 4326855 ~ Process for beneficiating and stabilizing coal/oil/water fuels
US 4273078 ~ Fuel supply system
US 4218221 ~ Production of fuels
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US 3941552 ~ Burning water-in-oil emulsion containing pulverized coal
US 3696973 ~ Hand-Held Air Compressor and Liquid Spray Device
FR 2196011 ~ No English title available.
FR 2190247 ~ No English title available.
FR 2113655 ~ No English title available.
WO 8203085 ~ Processes for Clewaning Minerals...
EP 0020711 ~ Fuel and Water Emulsification System.
EP 0016184 ~ Fuels and Methods for their Production
DE 2239408 ~ No English title available.
DE 2230071 ~ No English title available.
DE 1447328 ~ No English title available.
CH 657067 ~ Process for separating suspended solids and agglomerated other solids in suspending and bonding liquids respectively
CH 572578 ~ No English title available.
CH 562991 ~ No English title available.
CH 536132 ~ No English title available.
CA 1104345 ~ Residual Oil in Emulsion of Water with Distillate Oil
CA 973795 ~ Combustion Method Comprising Burning an Intimate Emulsion of Fuel and Water
CA 967947 ~ Apparatus for Carrying Out Ultrasonic Agitation of Liquid Dispersions
CA 963375 ~ Combustion Method Comprising Burning an Intimate Emulsion of Fuel and Water
CA 962905 ~ Apparatus and Method for Producing a Fuel-Air Mixture by Sonic Energy
BR 8108998 ~ No English title available.
BE 886087 ~ No English title available.
BE 787603 ~ No English title available.
BE 785280 ~ No English title available.
BE 774982 ~ No English title available.
NL 8006086 ~ No English title available.