Patent Application
20110265370
1. Field of the Invention
The present invention relates to air-water-hydrocarbon three phase emulsified fuel. More specifically, the invention relates to air-water-hydrocarbon three phase emulsified fuel prepared by adding water, air, and emulsifier compositions to liquid hydrocarbon fuels, and to methods of preparation and uses of the emulsions.
2. Description of the Related Art
It is known that the combustion of liquid hydrocarbons, for example for feeding internal combustion engines or for producing heat, leads to the formation of numerous pollutants, in particular soot, particulates, carbon monoxide (CO), nitrogen oxides (NOx), sulphur oxides (SOx), and noncombusted hydrocarbons, which contribute significantly towards atmospheric pollution.
It is also known that the addition of controlled amounts of water to fuel can significantly reduce the production of pollutants. It is believed that this effect is the result of various phenomena arising from the presence of water in the combustion zone. For example, the lowering of the peak combustion temperature by water reduces the emission of nitrogen oxides (NOx), the formation of which is promoted by high temperatures. In addition, the instantaneous vaporization of the water promotes better dispersion of the fuel in the combustion chamber, thereby significantly reducing the formation of soot, particulates and CO. These phenomena take place without adversely affecting the yield for the combustion process.
It is also known that the addition of controlled amounts of water to viscous fuels like heavy petroleum, vacuum residuum and high numbered fuel oils, can significantly lower the pour point and reduce the viscosity of the original fuel, reducing the need of heating before they can be pumped.
Several solutions have been proposed in attempts to add water to liquid fuel before or at the time of use, which is before the fuel is injected into the combustion chamber, or directly into the chamber itself. The most promising and numerous efforts made were directed towards the formulation of emulsions between liquid hydrocarbons and water in the presence of emulsifiers (surfactants) for the purpose of uniformly dispersing the water in the hydrocarbon phase and to stabilize the emulsion.
For example, patent EP-A-475 620 describes micro-emulsions of a diesel fuel with water, which contain a cetane improver and an emulsifying system comprising a hydrophilic surfactant and a lipophilic surfactant. The publication however refers only to a Diesel emulsion that reduces smoke, soot emissions, particulate emissions, and NOx emissions, however not improving combustion or using other original hydrocarbon components (i.e. heavy fuel oil) other than diesel.
Patent EP-A-630 398 describes a fuel in the form of an emulsion consisting of a hydrocarbon fuel, from 3 to 35% by weight of water and at least 0. 1% by weight of an emulsifying agent such as those consisting of a sorbitan oleate, a polyalkylene glycol and an ethoxylated alkylphenol. This publication however refers only to a process in which the emulsion forms from a mechanical mixture, and it does not involve air in the process.
Patent publication WO/1992/19701 describes a process for reducing the emission of NOx from a gas turbine, in which an emulsion of water with a diesel fuel is used. This publication however refers only to a process for reducing nitrogen emissions and improving the combustion efficiency of a turbine. It is a mechanic process that does not involve a stable three phase micro emulsion.
Patent publication WO/1994/003560 describes a method for generating an oil-in-water super heavy oil emulsion fuel having a good fluidity and a low unburned content. This publication however is limited and refers only to an emulsion fabricated from superheavy oil and a method for generating deteriorated oil-in-water oil emulsion fuel, which is limited to superheavy oil with a volatile content of 12% by weight or less at 340° C. Therefore, the molecular weight is larger than that of the components constituting ordinary oils
A related reference corresponds to WIPO patent publication WO/1999/054426 where Rudolph W. Gunnerman discloses Aqueous Emulsion Fuels from Petroleum Residuum. The publication, however, refers to a macro-emulsion formed by emulsifying the fuel oil with water or an aqueous liquid. The fuel oil forms the dispersed phase and the aqueous liquid forms the continuous phase. One of the significant differences is that the present invention, a three-phase emulsified fuel, has the hydrocarbons and air forming the dispersed phase and the aqueous liquid forming the continuous phase.
Additionally, Gunnerman documents one of the problems with the handling and transportation of heavy fuels in that they require “heating” before they can be pumped. See last paragraph of the background of the invention. This is precisely one of the objectives in the present invention, namely, to reduce the viscosity of the emulsified fuel so that it can be better handled without requiring “heating”.
Furthermore, the Gunnerman reference fails to disclose the need to pump air in the macro-emulsion, as required in the present claimed invention.
Both the use of water-in-hydrocarbon and hydrocarbon-in-water emulsions have been proposed. The most pertinent related prior art dealing with the formation of hydrocarbon-in-water emulsions from viscous hydrocarbons for use as a combustible fuel are British patent specification No. 974,042; U.S. Pat. No. 4,618,348 “Combustion of Viscous Hydrocarbons”; U.S. Pat. No. 4,923,483 “Methods for the Formation, Processing, Transportation and End Use of a Hydrocarbon-in-Water Emulsion”; U.S. Pat. No. 5,437,693, “Heavy Oil Emulsion Composition”; and WIPO patent publication No. WO/1999/054426, “Aqueous Emulsion Fuel from Petroleum Residuum-Based Fuel Oils”. Additional prior art patents dealing with the formation and transportation of hydrocarbon-in-water emulsions of the oil-in-water (o/w) and water-in-oil (w/o) type are U.S. Pat. Nos. 5,437,693; and 3,958,915.
There are no processes of developing an emulsified fuel, to the best of applicant's knowledge, that include the mixing of liquid hydrocarbons with active ingredients to develop a three phase emulsified fuel comprising liquid hydrocarbons, air and water, the hydrocarbon and the air forming the dispersed phase and the aqueous liquid forming the continuous phase.
The three-phase emulsified fuel subject of this application is an improvement in its handling and it is also easier to transport. Additionally, it provides for a cleaner and more efficient combustion of viscous fuels like heavy petroleum, vacuum residuum, petroleum distillate fractions, such as oil Nos. 4, 5, and 6.
Other documents describing the closest subject matter provide for a number of more or less complicated features that fail to solve the problem in an efficient and economical way. None of these patents suggest the novel features of the present invention.
The present invention relates to an air-water-hydrocarbon three phase emulsified fuel prepared by adding water, air, and emulsifier compositions to liquid hydrocarbon fuels, to the methods of preparation, and to the uses of the said emulsions. More specifically the invention relates to a three-phase emulsion fuel prepared by emulsifying heavy hydrocarbons such as bunker fuel oil (numbers 4, 5 and 6) and heavy petroleum, with water or an aqueous liquid, air, and emulsifier compositions to be used as an alternative energy fuel that offers the advantages of lower viscosity, higher performance and cleaner burning By heavy hydrocarbons, it is understood to include all hydrocarbons with an API less than 16.0. The invention refers also to the methods of preparation of the above said fuel and its use in internal combustion engines, boilers, heaters, furnaces, combustion turbines or power plants.
The emulsified fuel is produced in a process plant or directly on a user's premises. It is a three-phase micro-emulsion, which is composed of hydrocarbon-air-water-, which is stable and homogenous. Compared to the use of crude oil, refinery residues or fuel oil, this type of emulsion results in fuels with less viscosity, greater efficiency and is less contaminant.
Heavy petroleum, bunker fuel oil Nos. 4, 5, and 6 can be converted into low-viscosity, clean-burning liquid fuels by combining the oil with an aqueous liquid and air to form a micro-emulsion, and incorporating sufficient emulsifier compositions (surfactants like Ox and Px) to stabilize the emulsion. The resulting three-phase fuel micro-emulsion is useful as a substitute for the non-emulsified fuels. For example, the micro-emulsion prepared from fuel oil No. 6 can be used in any furnace, boiler, engine, combustion turbine or power plant where fuel oil No. 6 or lower-numbered fuel oils have heretofore been known for use. Also, the micro-emulsion prepared from heavy crude oil can be used as a substitute for fuel oil No. 6 or lower-numbered fuel oils. For any of the above-numbered fuel oils, the viscosity of the resulting micro-emulsion is low enough to permit pumping of the emulsion at lower temperatures or even at ambient temperature, which is particularly valuable for micro-emulsions formed with heavy petroleum or bunker fuel oils No. 4, 5 and 6. Furthermore, the burning of the three-phase air-water-hydrocarbon micro-emulsion offers significant reductions in nitrogen oxides (NOx) and particulate emissions relative to the non-emulsified fuel oil. This reduces the need and cost of exhaust gas treatment. There is also a significant reduction in the amount of soot generated, which reduces maintenance and, in boilers, improves heat transfer efficiency.
In general, the fuel component of the micro-emulsion undergoes a more complete combustion, which leads to improvements in fuel efficiency and thermal efficiency. In addition, the ability of the micro-emulsion to be pumped at lower or ambient temperatures lowers maintenance costs and capital costs since it eliminates the need for heated or lined transport vessels and pipelines. Micro-emulsions prepared from heavy crude oil offer the further advantage of having the characteristics of the above-numbered fuel oils without requiring blending with a cutter stock or a distillated fraction. This provides a less expensive alternative to the above-numbered fuel oils.
It is therefore one of the objects of the present invention to provide a micro-emulsified fuel that can be pumped and transported more easily and that burns more efficiently.
It is another object of this invention to provide a method to develop the emulsified fuel that is inexpensive to implement and maintain while retaining its effectiveness.
Further objects of the invention will be brought out in the following part of the specification, wherein detailed description is for the purpose of fully disclosing the invention without placing limitations thereon.
With the above and other related objects in view, the invention consists in the details of construction and combination of parts as will be more fully understood from the following description, when read in conjunction with the accompanying drawings in which:
The three-phase micro-emulsion fuel according to the present invention has utility in connection to an easier handling and transportation, and a cleaner and more efficient combustion of viscous fuels like heavy petroleum and fuel oils Nos. 4, 5, and 6.
The micro-emulsion has droplets of the dispersed phase that are small enough to give the emulsion the appearance of a homogeneous single liquid phase. The micro-emulsion is one in which the continuous phase is the aqueous liquid and the dispersed phase is the fuel oil inside an air bubble. The droplet size (of the dispersed phase) can be controlled to some extent by using a conventional pneumatic mixer (Ingersoll Rand Compressor, Dublin, Ireland or similar) and/or a high shear in line mixer with work heads (Silverson 450 LS, Ohio, USA or similiar). The droplet size can be reduced by decreasing the size of the work heads' holes through which the micro-emulsion is forced. The droplet size can also be controlled by the selection and amount of additives.
The relative amounts of dispersed and continuous phases can vary while still falling within the scope of the invention. The dispersed phase will generally constitute from about 70 to 80% by volume of the micro-emulsion and the continuous phase from about 10 to 25% by volume of the micro-emulsion. The percentage of the continuous phase is directly dependant on the API° and viscosity of the heavy petroleum or fuel oil used. The lower the API, the greater the percentage of the aqueous continuous phase.
The continuous phase of the micro-emulsion contains water as its major component and emulsifying additives. Since the micro-emulsions contain additives, some or all of which are miscible with or soluble in water, the aqueous liquid is an aqueous solution of these additives.
The emulsifying additives (surfactants) play an essential roll for the preparation of the emulsified fuel according to this invention. The emulsifying additive can be a mixture of emulsifying agents, detergents, wetting agents, dispersing agents, surfactants, and other components that serve a variety of functions, such as for example increasing lubricity, mixing aids, and heat stabilization. The choice can include anionic and nonionic agents.
In all cases, the formation of the emulsion can be facilitated by dividing the process in two steps: first incorporating the emulsion additive Ox that opens and disperse the hydrocarbon clusters, and second incorporating the emulsion stabilizing additive Px that forms and stabilizes the final three-phase micro-emulsion. Hydrocarbon molecules have the tendency to group and form long molecular clusters or chains. The presence of these clusters or chains does not allow for oxygen molecules to come in contact with fuel molecules. Because of this, the hydrocarbon molecules, which make up the fuel, do not burn completely. The residue or byproduct composed of partially oxidized molecules is exhausted as gaseous emissions that add to pollution. The present invention obviates this problem.
The three-phase micro-emulsion is prepared by mixing viscous fuels, such as heavy petroleum and petroleum distillate fractions (fuel oil Nos. 4, 5, and 6), with emulsifiers Ox, Px, and water in a ratio between 10 and 25% by volume followed by pneumatic agitation. Thus, a three-phase micro-emulsion is obtained, leaving the hydrocarbon and air components as the dispersed phase. The three-phase micro-emulsion alters the physical characteristics of the original hydrocarbon component used by significantly diminishing its viscosity, given the presence of water, emulsifying agents, and air that produce a reduction of viscosity and interlaminar friction.
The process to make the emulsified fuel comprises:
In one of the embodiments of the invention, the fuel's viscosity and aqueous combination was measured over time as a constant pneumatic agitation source was applied. In a tank holding 50,000 gallons, 38,000 gallons of fuel oil No. 4 (heavy hydrocarbon) was deposited and mixed with 2,500 gallons of the Ox additive and water mixture that had 200 gallons of Ox and 2,300 gallons of water. The mixture was pneumatically agitated for 2.0 hours, introducing air at the rate of 3,400 cubic meters per hour.
After the 2.0 hours, 7,500 gallons of a mixture of Px and water was added. The mixture of the Px additive and water consisted essentially of 400 gallons of Px additive and 7,100 gallons of water. The Px and water mixture was added through a mixing pump. Again, pneumatic agitation was applied, now at the rate of 5,100 cubic meters per hour for 3 hours.
The resulting micro-emulsion was with bubbles (hydrocarbon surrounded by air) of 40 to 80 microns in size and a viscosity of less than 40 cSt at 80° C.
In addition to lowering the viscosity of the heavy hydrocarbon, the resulting emulsified fuel has a higher combustion efficiency, as a result of being a three phase emulsion hydrocarbon/air/water. See
When the emulsified fuel is exposed to oxygen present in air, it facilitates the combustion reaction. The emulsified fuel produces a fast and improved combustion of the hydrocarbon molecules and it is far more efficient and clean than heavy fuels and numbered fuel oils, with the added advantage of reduced pollutant emissions.
In order to develop the emulsified fuel using the double emulsion process to obtain a three-phase emulsion, it is necessary to specifically use the additives Ox and Px, which include biodegradable substances applied in the previously stated conditions.
The characteristics of the emulsified fuel include that it is stable for periods greater than six months at room temperature. It has a high thermal efficiency and it is non-explosive. It is safe to produce, transport, handle and store. It has a low pour point and good combustion characteristics. It is an environmentally friendly fuel. It is a non-refined fuel, which looks, is handled and burns like a fuel with a higher API gravity than the original product. When preparing the emulsion, no flammable solvents are added to the original hydrocarbon, yet the emulsion provides easy ignition and combustion characteristics. It has a density below one, which allows it to float in water.
In the embodiment, the emulsified fuel is in a liquid state and may be utilized to operate internal combustion engines, boilers, heaters, furnaces, combustion turbines or power plants. The emulsified fuel is an effective answer to three basic needs that the world faces today: the growing need for low cost energy, the preservation of a non-renewable resource and the preservation of the environment.
The benefits obtained from the use of the emulsified fuel have been evaluated both technically and environmentally in several laboratories, and in industrial tests under the supervision of qualified scientists. When compared to the usage of heavy fuels, the emulsified fuel presents the following advantages: it homogenizes and stabilizes the fuel, it opens up the molecular clusters or aggregates exposing the hydrocarbon molecules to the oxygen molecules (O2), it facilitates the handling and transportation, it improves combustion, it improves fuel performance, it reduces particulate and contaminating gas emissions, and it reduces operational costs.
The following analysis compares the viscosity and the burning performance of crude oil (12.3° API) and the emulsified fuel created from the same crude oil (12.3° API). The emulsified fuel is designed to fraction molecular clusters with the purpose of exposing the hydrocarbon chains to the oxygen molecules available, thus, increasing fuel oxidation and as a consequence, diminishing the total amount of pollutant emissions.
As seen in Chart 1, the following results of the analysis resulted from the compared tests carried out in actual operational conditions in a pyrotubular boiler that usually used to burn the 12.3° API crude oil.
With regard to performance and efficiency, although the emulsified fuel has a smaller gross caloric potential than crude oil because of its added fuel combustion efficiency, fuel consumption is diminished between 4% and 13%. This can be proven not only by fuel consumption figures but also by the reduction of pollutant particulate emissions (partially combusted carbon) and the absence of carbonate monoxide in the resulting emissions, which translates into a complete or near total combustion, which reflects a far better usage of the available caloric potential.
The emulsified fuel has a lower pouring point, is less viscous, requires less pre-heating and less pressure for its injection, generates less polluting emissions and is far more efficient.
As seen in Chart 2, the following results of the analysis resulted in emission figure comparisons between crude oil and the emulsified fuel.
In addition to the elimination of the carbonate monoxide production and the reduction of the particulate matter concentration, the use of the emulsified fuel in comparison to the use of crude oil, significantly reduces the sulfur oxides emissions (SOx) and nitrogen oxides (NOx).
As seen in Chart 3, the following results of the analysis summarize the emulsified fuel combustion exhaust gas composition figures.
The emulsified fuel when compared to the non-emulsified fuel has greater combustion efficiency. This advantage translates into a considerable increase in the reduction of contaminant emissions to the environment and increased efficiency. In addition, the emulsified fuel is less viscous and easier to handle.
In sum, the emulsified fuel, when compared to the non-emulsified fuel, comprises less viscosity, lower pour point, requires less injection pressure, and less injection temperature, it is easier to handle, has greater efficiency, has better performance, requires less consumption, and produces less CO emissions, less NOx emissions, less SOx emissions, and less particulate matter emissions.
The foregoing description conveys the best understanding of the objectives and advantages of the present invention. Different embodiments may be made of the inventive concept of this invention. It is to be understood that all matter disclosed herein is to be interpreted merely as illustrative, and not in a limiting sense
The present application is a continuation-in-part of pending U.S. patent application Ser. No. 11/272,406, filed on Nov. 14, 2005, which is hereby incorporated by reference.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 11272406 | Nov 2005 | US |
| Child | 12840348 | US |
