Water in fuel microemulsions via HLD formulation methodology

Abstract

Water in fuel microemulsions including a surfactant package produced through a Hydrophilic Lipophilic Difference (HLD), and methods that provide advanced formulation and surfactant identification methodology of the microemulsions. The fuel may be one or more light fuel oils including gasolines, kerosene, aviation fuels, diesel fuels, marine fuels, light fuel oils, and / or one or more heavy fuel oils and bunker fuels, and / or other alternative fuels including biodiesels, renewable diesels, synthetic diesels, efuels, and / or may alternatively be or include hydrosols. The surfactant package may comprise short chain and / or long chain non-ionic or ionic surfactants and chemicals such as nonylphenol ethoxylate, sorbitan esters, alkyl polyglucosides, sodium dioctyl sulfosuccinate, tridecyl alcohol ethoxylate, ethyl hexanol, 2-ethyl-hexyl nitrate, biocides, lubricity improvers or fuel dye. The microemulsions may be near clear and transparent solutions when the fuel is lighter grades of fuel oils and dark black when the base fuels are heavy marine fuels such as HFO.

Description

WATER IN FUEL MICROEMULSIONS VIA HLD FORMULATION METHODOLOGY

[0001] BACKGROUND INFORMATION

[0002] Technical Field

[0003] The present disclosure relates to compositions and methods of formulating same, and more particularly to surfactant package(s) and to water in fuel microemulsions made via Hydrophilic Lipophilic Difference (HLD) formulation methodology, where the specific ratio between surfactants, oil (fuel), and water is specified by the HLD + net-average-curvature (NAC) model.

[0004] Background Art

[0005] Various additives have been suggested in the past to deal with issues like mechanical noise in leaded hydrocarbon fuels and to boost the efficiency and performance of standard hydrocarbon fuels. Research on water-blended fuels, known as hydrosols, has shown changes in engine performance and exhaust characteristics when water is mixed during combustion. On one side, adding water lowers combustion temperatures and the energy content of high-water hydrosol fuel, which could make it hard for engines to start. But on the flip side, emulsifying hydrocarbon fuel with water cuts down on fossil fuel use and the corresponding cost.

[0006] To prevent water-fuel emulsion bonds from breaking and separating over time, surfactants are added to the mixed fuels to prolong stability. Normal HLB formulated emulsions or nanoemulsions will naturally separate over time. “HLB” is Hydrophilic-Lipophilic Balance.

[0007] United States Patent No. 7,182,797 to Mekonen talks about fuel compositions mainly made up of water-free hydrocarbon fuels in hydrosol form,plus fuel additive packages featuring sorbitan oleate, a polyoxyethylene alcohol, an alkylene glycol, and an amine. This patent focuses on hydrosols made of hydrocarbon fuel, water, and a stabilizing surfactant, aiming for better combustion efficiency and lower CO2 emissions.

[0008] PCT Publication No. WO / 2011 / 028182 (Teo) outlines a way to make biodiesel and glycerin, organic fuel additive compositions, and emulsion fuels. These aim to improve fuel combustion efficiency. The '797 patent to Mekonen also deals with cutting CO2 emissions. However, concerns about greenhouse gas emissions, especially NOx and SO2emissions, and Particulate Matter (PM) emissions are just as important due to their bad effects on health and engine performance. The Teo publication also aims to reduce environmental pollution, pointing out the downsides of regular water-based emulsion diesel, like reduced fuel power and higher manufacturing costs. It presents organic fuel additive compositions comprising surfactant, glycerin, polyethoxy-ester, water, and diesel, all mixed together, with water only described by its pH range of 6.8 to 7.2.

[0009] United States Patent No. 10,995,291 B2 (Gomez) discloses improved fuel compositions and additive packages designed to significantly reduce emissions of CO2, NOx, SO2, PM2.5, PM10, and Black Carbon during combustion, achieving up to 90% reductions compared to standard fuels across a wide temperature range. These formulations enhance fuel economy, diminish engine wear, and lower maintenance requirements by reducing engine temperature, mechanical friction, and noise through enhanced combustion and fuel lubricity. Base fuels, either water- free hydrocarbon fuels like gasolines and diesel fuels or hydrosols containing hydrocarbon fuels with added water, are treated with the additive package, and emulsified with clean, soft water for improved stability and engine performance, maintained for up to a year or more through advanced emulsification techniques. The versatile additive package, adaptable to diverse industry needs without necessitating engine modifications, comprises sorbitan oleate, a polyoxyethylenealcohol, an alkylene glycol, and an amine, with the amine component playing a significant role in catalyzing reactions to reduce CO2 emissions during combustion. Additional optional ingredients, including specific oleates and polyoxyethylene alcohols, alongside toluene, xylene, VMP naphtha, and alkyl benzene for water- free fuels, are included to tailor the formulation to specific requirements.

[0010] The ‘291 patent discloses that an inline high pressure multi-cavitation force emulsion process, not requiring recirculation of mixture, provides enhanced submicron emulsification and low nanoemulsification, resulting in prolonged stability at various ambient conditions and resulting in increased fuel efficiency (work output enhancements) and fuel economy while also significantly reducing the level of multiple emissions constituents generated upon combustion of the fuels. The processes disclosed in the ‘291 patent rely on selecting surfactants with specific HLB values. The HLB system quantifies the balance between the hydrophilic (water-attracting) and lipophilic (oil-attracting) parts of a surfactant molecule. The HLB value indicates the degree to which a surfactant is more hydrophilic or lipophilic. In the HLB emulsification technique, surfactants with different HLB values are combined in precise ratios to achieve the desired balance for the specific emulsion being created. This method allows for the creation of emulsions with tailored properties, such as stability, droplet size, and compatibility with different phases.

[0011] However, the HLB methodology also has some limitations regarding lack of stability of the resulting emulsions at low and high operating temperature ranges, and not being thermodynamically stable. The HLB emulsification technique is widely used in industries such as pharmaceuticals, cosmetics, and food production.

[0012] Therefore, there is a need in the art for improved fuel compositions having a multifaceted ability to achieve one or more of high internal phase volume fractions,high stability, high versatility, and / or high compatibility, particularly with large volume fuel applications where some or all of these considerations are paramount.

[0013] There also remains a need for emulsions that are thermodynamically stable, and / or that enable reassembly in the event of emulsion phase separation, avoiding otherwise expensive waste of fuels and / or potential equipment damage with the presence of free-water above allowable industry fuel standard specifications.

[0014] There is a long felt need for effective utilization of aftermarket pour point suppressants, cetane improvers, and / or other additives when using fuels to further improve fuel operating conditions and / or engine combustion. The thermodynamic stability of an emulsion becomes crucial to reduce or prevent phase separation caused by chemical imbalances introduced by such aftermarket additives, and / or to reduce or avoid the presence of free water content in the fuel, conducing high engine performance and / or longevity of the emulsion.

[0015] There is a need in the art to enhance the stability of microemulsions and thereby facilitate broader applicability of the emulsification process and / or enable operation across a wider range of conditions. This includes reducing sensitivity to operating conditions, such as extreme temperatures, and / or promoting reassembly capability in the face of instability-inducing circumstances. By bolstering stability, the emulsification process becomes more resilient and versatile, accommodating diverse operational environments and / or other potential challenges.

[0016] There is a long felt need to reduce adverse environmental effects of combustion emissions of baseline fuels and emulsions, by substantially reducing emissions such as CO2, NOx, SO2, unburned hydrocarbons, particulate matter and / or black carbon, smoke exhaust opacity, and / or reduce the net base fuel consumption by meaningful amounts and / or improve the fuel efficiency. There remains a need to target human health concerns by significantly reducing fuel toxicity and / or emissions of particulate matter and / or black carbon.

[0017] There is a long felt need to reduce adverse environmental impacts and / or costs linked to fuel storage, handling and / or transportation, such as the probability and / or severity of spills, thereby heightening safety during storage, handling and / or transportation. Additionally, it would be advantageous to have fuels demanding lower hazardous materials classification and higher flash point, when compared to conventional fuels. This may translate to notable contributions in environmental preservation and / or cost efficiencies and / or safety within fuel storage, handling and logistics operations.

[0018] There is a long felt need for fuels that improve engine performance across various climatic conditions, and / or for fuels exhibiting heightened combustion efficiency, translating into improved fuel economy and / or efficiency. Moreover, there is a need for fuels that ease engine temperature regulation and / or reduce engine noise levels, culminating in smoother engine operation and / or enhanced operating experience across diverse environmental settings. Furthermore, it would be advantageous if fuels were available that contribute to the longevity and / or reliability of combustion engines by reducing wear and tear on mechanical components, for example by functioning as a cleaning agent, aiding in decarbonization, and / or functioning as a lubricity agent reducing friction and / or engine stress. Furthermore, it would be advantageous if fuels were available that contribute to lower engine operating temperatures and / or that mitigate engine strain and / or minimize fouling of critical engine components, resulting in reduced maintenance costs and / or extended engine lifespan. There is a great need for fuel formulations that reduce noise pollution by reducing engine noise levels.

[0019] At this time, there are no known fuel compositions and surfactant or bio- additive packages in water in fuel microemulsion fuels that are capable of prolonged thermodynamic stability and / or increased fuel efficiency (work output enhancements) and / or fuel economy, while also significantly reducing multiple harmful emissions generated during combustion of the fuels including but not limited to CO2, NOx, SO2, unburned hydrocarbons, particulate matter and / or blackcarbon, and exhaust smoke opacity. These emissions reductions may be accounted as tailpipe emissions and / or fuel lifecycle emissions, including the specific fuel consumption consideration in order to obtain the specific emissions results. Presently, there are no known assembly processes or methods of making microemulsion fuels employing HLD formulation methodology, including the net- average curvature (NAC) model to predict the amount of water that can be solubilized in the fuel for a given surfactant mixture and total surfactant concentration.

[0020] SUMMARY

[0021] In accordance with the present disclosure fuel microemulsions are described, as well as methods of making same, that reduce or overcome many of the faults of previously known compositions and methods.

[0022] In particular, I have designed unique fuel microemulsions which offer distinct advantages compared to regular emulsions and nanoemulsions. For the application of utilizing such water in fuel compositions in various types and speed diesel engines, turbine engines and boiler combustion, fuel microemulsions provide greater thermodynamical stability (compared with regular emulsions and nanoemulsions fuels). In certain embodiments, water droplets remain in the dispersed phase at a wide range of engine operating and environmental conditions. In certain embodiments, water droplets remain in the dispersed phase at any given engine operating and environmental conditions.

[0023] A first aspect of the disclosure are thermodynamically stable fuel microemulsions comprising (or consisting essentially of, or consisting of): a) a base fuel substantially in liquid phase; b) a surfactant package; andc) water (any type of water may be used, for example, but not limited to sea water, river water, potable water, city water, well water or the like, but preferably reverse osmosis and / or deionized water) having a resistivity ranging from about 0.02 Megaohm^cm to about 18 Megaohm^cm (or ranging from about 0.02 Megaohm^cm to about 0.10 Megaohm^cm, or ranging from about 0.10 Megaohm^cm to about 1 Megaohm^cm, or ranging from about 1 to about 18 Megaohm^cm, or ranging from about 1 to about 10 Megaohm^cm) at 25ºC, wherein the surfactant package comprises one or more surfactants selected based on hydrophilic-lipophilic difference (HLD) of a mixed combination of the base fuel, the surfactant package, and the water, where the HLD ranges from about -0.5 to about +3, the HLD indicating thermodynamic stability. In certain embodiments, the HLD ranges from +0 to +1, where the water solubilization in oil-continuous (reverse micelle) and bicontinuous microemulsion environments is maximized. In other embodiments, the additive package can be composed of surfactants that do not have a biological origin. In certain embodiments, the selection of the surfactants, their composition, and their concentration in the surfactant package is determined according to the net-average curvature (NAC) model.

[0024] A second aspect of this disclosure are methods of making the thermodynamically stable fuel microemulsions of the first aspect, one method comprising (or consisting essentially of, or consisting of): a) providing a base fuel substantially in liquid phase; b) selecting a first surfactant package; c) providing water having a resistivity ranging from about 0.02 Megaohm^cm to about 18 Megaohm^cm (or ranging from about 0.02 Megaohm^cm to about 0.10 Megaohm^cm, or ranging from about 0.10 Megaohm^cm to about 1 Megaohm^cm, or ranging from about 1 to about 18 Megaohm^cm, or ranging from about 1 to about 10 Megaohm^cm), at 25ºC;d) providing required input parameters of the base fuel, the first surfactant package, and the water to calculate hydrophilic-lipophilic difference (HLD) if the base fuel, the selected surfactant package, and the water were mixed; e) calculating a first hydrophilic-lipophilic difference (HLD1) using the required input parameters and a selected iterative HLD calculation algorithm; f) if the HLD1 is within a range of HLD ranging from about -0.5 to about +3, proceed to mix the base fuel, the first surfactant package, and the water (preferably, using a low energy, low footprint static mixer (in certain embodiments at a temperature ranging from about 0 ºC to about 100 ºC, or from about 37 ºC to about 90 ºC, or from about 37 ºC to about 41 ºC)) to produce a thermodynamically stable, self-healing and / or self-assembling fuel microemulsion; g) if the HLD1 is not within a range of HLD ranging from about -0.5 to about +3, select a second surfactant package to calculate a second hydrophilic-lipophilic difference (HLD2) using the required input parameters and the selected iterative HLD calculation algorithm.

[0025] A third aspect of this disclosure are methods of making the thermodynamically stable fuel microemulsions of the first aspect, one method comprising (or consisting essentially of, or consisting of): a) providing a base fuel substantially in liquid phase; b) selecting one or more surfactants to be included in the surfactant package; c) providing water having a resistivity ranging from about 0.02 Megaohm^cm to about 18 Megaohm^cm (or ranging from about 0.02 Megaohm^cm to about 0.10 Megaohm^cm, or ranging from about 0.10 Megaohm^cm to about 1 Megaohm^cm, or ranging from about 1 to about 18 Megaohm^cm, or ranging from about 1 to about 10 Megaohm^cm), at 25^C; d) providing required HLD-NAC parameters of the base fuel, the one or more surfactants, a target total surfactant content, and a target water content in the fuel;e) calculating phase volumes of microemulsion, excess oil, and excess water for a given range of surfactant composition using HLD-NAC phase volume algorithm; f) selecting a surfactant composition for the surfactant package that, according to the HLD-NAC algorithm, produces a single phase microemulsion without excess oil or water phases (preferably, using a low energy, low footprint static mixer (in certain embodiments at a temperature ranging from about 0 ºC to about 100 ºC, or from about 37 ºC to about 90 ºC, or from about 37 ºC to about 41 ºC)).

[0026] The fuel microemulsions and methods of the present disclosure remove or reduce one or more challenges encountered with standard emulsions and nano- emulsions produced via the HLB methodology by introducing improved fuel compositions and surfactant package specifically tailored to the HLD formulation methodology. These advancements lead to significant reductions in emissions such as CO2, NOx, SO2, unburned hydrocarbons, particulate matter, and / or black carbon emissions, and exhaust smoke opacity. These emissions reductions may be accounted as tailpipe emissions and / or fuel lifecycle emissions, including the specific fuel consumption consideration in order to obtain the specific emissions results. Furthermore, the enhanced fuel compositions and surfactant package result in improved engine performance such as fuel economy, net fuel efficiency, and / or reduced engine wear and / or maintenance due to lower engine temperatures and / or minimized mechanical friction and / or noise, attributed to heightened fuel lubricity and enhanced combustion profile. This may include high speed diesel engines, mid-speed diesel engines, low-speed diesel engines, turbine engines and boilers, utilized in various industry sectors.

[0027] The usable base fuels may encompass a wide range of water-free hydrocarbon or biobased substantially liquid fuels, including gasolines, diesel fuels, marine gas oils, marine diesel oils, biodiesel fuels, biomass diesel fuels, renewable fuels, synthetic fuels, light and heavy fuel oils, kerosene fuels, aviationfuels, biofuels, e-fuels (for example mixtures of so-called “green” hydrogen and CO2 derived from direct air capture (DAC) CO2 plants), and algae-fuels, along with hydrosols containing hydrocarbon fuels supplemented with water. Water in fuel microemulsions of the present disclosure can be created with this wide range of liquid fuels in whole or in part, meaning up to 100 volume percent of any of the mentioned base fuels, or, in certain embodiments, as a blend of two or more base fuels at many ratios and combinations. For example, one embodiment may comprise blending 80 percent marine diesel with 20 percent biodiesel. Another embodiment may comprise blending 50 percent ultra-low sulfur diesel (ULSD) and 50 percent renewable diesel.

[0028] As used herein “water-free” means that the fuels are intended to be up to 100 percent hydrocarbon, but may have some water therein, for example, but not limited to, up to 0.5 percent, or up to 1 percent, or up to 2 percent or up to 3 percent water, by volume of total base fuel. As used herein “substantially liquid” means that the fuels are intended to be primarily liquid phase, but may have some gaseous phase therein, for example, but not limited to, up to 0.5 percent, or up to 1 percent, or up to 2 percent or up to 3 percent gaseous phase, by volume of total base fuel. Certain embodiments may comprise combining a water in fuel microemulsions with another fuel at or just prior to the point of injection into the engine (or burner in the case of industrial boilers or industrial furnaces). Hydrogen injection (the hydrogen produced by electrolysis or other means, such as catalytic reforming of straight chain hydrocarbons) in the engine intake system, could provide significant emissions and engine performance advantages. Certain embodiments may comprise adding nanoparticle materials, metallic and / or non-metallic, in the water in fuel microemulsions that may further improve engine performance and emissions reduction advantages.

[0029] By blending these fuels with the innovative surfactant package and emulsifying them with water, notable enhancements in fuel stability and / or engine performance may be achieved. Moreover, with the application of advanced emulsification techniques of the HLD methodology, in certain embodiments the fuel microemulsions resulting from emulsified fuel-water surfactant package can maintain thermodynamic stability at normal environmental, fuel storage and transfer, and engine operating conditions, demonstrating sustained efficacy and / or durability.

[0030] In certain embodiments, surfactant package preparation of mixing and / or dosing process may comprise various surfactants and other chemicals, or as a single package, or individual surfactants and chemicals, independently dosed and / or added in the blending process in various sequences. Additional additives may be dosed and / or added in the blending process by additional inlets and dosing systems or processes, not limited to cetane improver, pour point depressants, biocides or nanoparticle materials. Blending processes may consist of batch or in-line continuous blending processes, or the like.

[0031] In certain embodiments, microemulsion fuel preparation of mixing and / or dosing process may comprise various surfactants and other chemicals, or as a single package, or individual surfactants and chemicals, independently dosed and / or added in the blending process in various sequences. Additional additives may be dosed and / or added in the blending process by additional inlets and dosing systems or processes, not limited to cetane improver, pour point depressants, biocides or nanoparticle materials. Blending processes may consist of batch or in-line continuous blending processes, or the like.

[0032] In certain embodiments, microemulsion fuel preparation may comprise a pre- blend of base fuel such as but not limited to ULSD or MGO fuel with the specific andcalculated individual surfactants or surfactant package and other additives already built-in as a ready to mix concentrate (base fuel, surfactant(s), other chemical(s)), where this pre-blend is ready for the dosing of just water in order to complete the microemulsion fuel. (“ULSD” means ultra-low sulfur diesel, and “MGO” means marine gas oil.) Additional additives may be dosed in the blending process by additional inlets and dosing systems or processes, not limited to cetane improver, pour point depressants, biocides, nanoparticle materials. Blending processes may comprise batch or in-line continuous blending processes, or the like.

[0033] With respect to temperature, there are several important considerations:

[0034] Environmental conditions;

[0035] Fuel storage and transfer conditions (which relates a little on the environmental conditions); and

[0036] Engine operating conditions.

[0037] Fuel must be able to navigate through the different scenarios. Winter and summer blends of the water in fuel microemulsions of the present disclosure can be produced for each specific season, where they are thermodynamically stable from about -10 ºC to 90 ºC. This also means that the water in fuel microemulsions of the present disclosure should meet cycles of different temperatures within this range and maintain its stability.

[0038] Regarding environmental temperature ranges, this may range from -10 ºC in cold seasons and up to 55 ºC in desert areas.

[0039] Regarding fuel storage and transfer conditions, these may be similar to environmental conditions.

[0040] Regarding engine operating conditions, this may range from environmental conditions (due to the water in fuel microemulsions of the present disclosure beingstored “onboard” in equipment fuel tank(s), filter housings, various filtration systems, transfer pump(s) and fuel lines) with a lower temperature as low as -10 ºC. Fuel flowing through the engine during operation may cause the fuel to heat up to temperatures close to 90 ºC in the fuel injection system when the engine shuts off, therefore, water in fuel microemulsions of the present disclosure should be able to withstand this hot temperature for at least 30 minutes as the engine cools down and fuel pressure lowers. Water in fuel microemulsion is capable of withstanding much higher temperatures (>100 ºC) while kept under pressure in closed-looped pressurized systems. These temperature fluctuations ranging from environmental conditions to storage and transfer conditions to engine operating conditions are important to consider since the water in fuel microemulsion would have to navigate through these cycles in real market conditions.

[0041] Fuel storage and transfer conditions may also include water in fuel microemulsions of the present disclosure flowing through various types of transfer pumps and filters, for example but not limited to water / fuel separators, low and high micron filters, centrifuge filtration systems, where the water in fuel microemulsions of the present disclosure should remain stable for operation. In addition, fuel storage tanks may be for example, but not limited to, stainless steel, carbon steel, plastic, fiber glass, and aluminum.

[0042] The fuel microemulsions of the present disclosure and methods of making same rely primarily on chemical energy applied (vs. primarily mechanical energy) from the chemistry obtained from HLD formulation process to form bicontinuous fuel microemulsions that are thermodynamically and long-term stable. Fuel microemulsions and methods of making the same of the present disclosure eliminate the requirement for high energy emulsification processes such as shear mixers, high-pressure or ultrasonics to obtain smaller sized water droplets for the assembly of the fuel microemulsions, although one or more of these high-energymixing techniques may still be used if desired, either alone or in conjunction with low-energy mixing techniques.

[0043] These and other features of the compositions and methods of the disclosure will become more apparent upon review of the brief description of the drawings, the detailed description, and the claims that follow. Wherever the terms “comprise” and “comprising” are used herein, other embodiments where these terms are substituted with “consisting essentially of” are explicitly disclosed herein. Wherever the terms “comprise” and “comprising” are used herein, other embodiments where these terms are substituted with “consisting of” are explicitly disclosed herein. Moreover, the use of negative limitations is specifically contemplated; for example, certain compositions may comprise several chemical components and features but may be devoid of certain optional chemicals and / or other features. For example, certain compositions may be devoid of ionic surfactants, or devoid of bio-surfactants. For example, certain systems for carrying out methods may be devoid of auxiliary tanks, pumps, and other equipment. As another example, methods of this disclosure may be devoid of high intensity mixers, high-shear mixers, high-pressure pumping, or ultrasonic mixers, or other expensive equipment.

[0044] BRIEF DESCRIPTION OF THE DRAWINGS

[0045] The manner in which the objectives of this disclosure and other desirable characteristics can be obtained is explained in the following description and attached drawings in which:

[0046] FIG.1 schematically illustrates a water in fuel macroemulsion;

[0047] FIG. 2 schematically illustrates a water in fuel microemulsion in accordance with the present disclosure;

[0048] FIG 3. is a graphical representation of the ternary phase diagram presenting the relationship between oil, water, and surfactant components, indicating the region where a continuous fuel microemulsion of base fuel (oil) is formed (circles), and the presence of undesirable emulsions (crosses), where the dashed line in FIG.3 corresponds to the HLD-NAC predicted boundary between single phase microemulsions and the multiphase emulsion zone;

[0049] FIG 4. is a logic diagram of one HLD method in accordance with the present disclosure;

[0050] FIG. 5 is a logic diagram of one algorithm used to undertake the HLD-NAC method in accordance with the present disclosure; and

[0051] FIG.6 is a table of HLD-NAC input parameters used for the system of sorbitan monooleate and NPE5 (nonylphenol ethoxylate with an average of five ethylene oxide groups), where the bottom of FIG. 6 presents the HLD-NAC predicted solid lines of the upper and lower microemulsion boundaries along a phase scan produced by changing the proportion of sorbitan monooleate and NPE5, and the predicted lines are superimposed on a picture of the experimental scan, illustrating that vial 5 produces a single phase water-in fuel microemulsion, consistent with the HLD-NAC model prediction.

[0052] It is to be noted, however, that the appended drawings are not to scale and illustrate only typical embodiments of this disclosure, and are therefore not to be considered limiting of its scope, for the disclosure may admit to other equally effective embodiments.

[0053] DETAILED DESCRIPTION

[0054] In the following description, numerous details are set forth to provide an understanding of the disclosed methods, compositions, and apparatus. However, it will be understood by those skilled in the art that the methods, compositions, and apparatus may be practiced without these details and that numerous variations or modifications from the described embodiments may be possible. All patent applications, patents, and non-patent literature referenced herein are hereby explicitly incorporated herein by reference. In the event definitions of terms in the referenced patents, patent applications, and non-patent literature conflict with how those terms are defined in the present patent application, the definitions for those terms that are provided in the present patent application shall be deemed controlling. Where a range of values describes a parameter, all sub-ranges, point values and endpoints within that range are explicitly disclosed herein. This document follows the well-established principle that the words “a” and “an” mean “one or more” unless I evince a clear intent to limit “a” or “an” to “one.” For example, when I state “flowing a fuel into a tubing having a mixing impeller”, I mean that the specification supports a legal construction of “a tubing” that encompasses structure distributed among multiple physical structures, and a legal construction of “a mixing impeller” that encompasses structure distributed among multiple physical structures.

[0055] Microemulsions (sometimes referred to herein as microemulsion assemblies) of the present disclosure offer extensive stability at a wide range of cold to hot operating conditions (for example, but not limited to -10 ºC to about 100 ºC), lower carbon factor (pounds of CO2 generated per unit weight or volume), for example, but not limited to, 1 percent lower, 5 percent lower, or 10 percent lower, or greater than the underlying base fuel constituent, while reducing (for example, but not limited to, 1 percent lower, 5 percent lower, or 10 percent lower, or greater) production of Green House Gases (GHG) and numerous harmful emissions including but not limited to CO2, NOx, SO2, unburned hydrocarbons, particulate matter and black carbon, and exhaust smokeopacity. These emissions reductions may be accounted as tailpipe emissions and / or fuel lifecycle emissions, including the specific fuel consumption consideration in order to obtain the specific emissions results.

[0056] In certain embodiments, microemulsions of the present disclosure may exhibit improved net fuel efficiency (for example, but not limited to, 1 percent higher, 5 percent higher, or 10 percent higher, or greater), and / or improved net fuel economy (for example, but not limited to, 1 percent higher, 5 percent higher, or 10 percent higher, or greater), and / or near zero visible exhaust smoke.

[0057] In certain embodiments, microemulsions of the present disclosure comprising a fuel assembly and a surfactant package may comprise fuels selected from various light or heavy fuel oils including gasolines, kerosene, aviation fuels, diesel fuels, various marine fuels, and / or light fuel oils, and / or heavy fuel oils and / or bunker fuels, and / or other alternative fuels, for example, but not limited to biodiesels, renewable diesels, synthetic diesels, e-fuels, and / or fuel hydrosols.

[0058] In certain embodiments, microemulsions of the present disclosure may comprise a surfactant package, for example, but not limited to one or more short chain and / or long chain non-ionic and / or ionic surfactants such as nonylphenol ethoxylate, sorbitan esters, alkyl polyglucoside, sodium dioctyl sulfosuccinate, tridecyl alcohol ethoxylate, a monohydroxy alcohol having from 6 to 10 carbon atoms (for example ethyl hexanol), a nitrate cetane number enhancer having from 6 to 10 carbon atoms (for example 2-ethyl-hexyl nitrate), biocides, lubricity improvers (for example, but not limited to those described in U.S. Patent No. 5,882,364), and / or fuel dyes. Certain microemulsion embodiments may be near clear and transparent solutions when using the lighter grades of fuel oils and one or more of these surfactants.

[0059] Sorbitan is a mixture of isomeric organic compounds derived from the dehydration of sorbitol. The IUPAC (International Union of Pure and Applied Chemistry) name is: (3S)-2-(1,2-Dihydroxyethyl)tetrahydrofuran-3,4-diol. A common name is 1,4-anhydrosorbitol. The dehydration reaction usually produces sorbitan as a mixture of five- and six-membered cyclic ethers (1,4-anhydrosorbitol, 1,5- anhydrosorbitol, and 1,4,3,6-dianhydrosorbitol) with the five-membered 1,4- anhydrosorbitol form being the dominant product. The rate of formation of sorbitan is typically greater than that of isosorbide, which allows it to be produced selectively, providing the reaction conditions are carefully controlled. The dehydration reaction has been shown to work even in the presence of excess water.

[0060] In certain embodiments, microemulsions of the present disclosure address human health concerns by significantly reducing fuel toxicity and emissions of particulate matter and black carbon. In certain microemulsion embodiments, with emissions reductions of up to 50 percent, or up to 60 percent, or up to 70 percent, or up to 80 percent, or up to 90 percent compared to base fuels, the microemulsions may help alleviate adverse health effects associated with exposure to air pollutants, enhancing public health and well-being.

[0061] In certain embodiments, microemulsions of the present disclosure, by attaining a higher flash point and exhibiting fewer pollution characteristics, effectively diminish the probability and severity of spills, thereby heightening safety during storage, handling and transportation. Additionally, microemulsions of the present disclosure should have lower hazardous materials classification due to higher flash point when compared to conventional fuels, translating to notable contributions in safety and environmental preservation and cost efficiencies within fuel logistics operations. In certain embodiments, microemulsions of the present disclosure may lower engine operating temperatures by up to 5 percent, or up to 10 percent or up to 20 percent ormore, and mitigate engine strain and minimize the fouling of critical engine components, resulting in reduced maintenance costs and extended engine lifespan. In certain embodiments, microemulsions of the present disclosure may reduce noise pollution concerns by reducing engine noise levels by up to 2 percent, or up to 2.5 percent, or up to 3 percent or more. Improved lubrication of mechanical components ensures smoother engine operation, resulting in quieter engine performance and reduced cabin noise. These noise reduction benefits enhance overall comfort and driving experience while demonstrating the formulation's positive impact on engine health and longevity. In certain embodiments, microemulsions of the present disclosure may increase the conductivity by up to 5 percent, or up to 10 percent, or up to 20 percent or more, and mitigate safety concerns during handling, transportation and storage by reducing electrical static charge buildup.

[0062] Table 1 lists one example of a fuel microemulsion of the present disclosure that might characterize such microemulsions when a bio-fuel, such as bio-diesel is employed. Table 2 lists some compositions and properties. Table 1. Example Water in Fuel Microemulsions COMPONENT FUNCTION EXAMPLES rs, s,Table 2. Example Composition and Properties of Microemulsions Vol. % (broad Vol. % (narrow [00stable microemulsions. For batch blending of fuel microemulsions, a simple low RPM propeller may be used. For inline blending processes, only static mixers may be used. In both instances the methods are low energy, nearly just agitation. Importantly, our previous attempts at formulating our fuel macroemulsions and nanoemulsions (using HLB method) required high shear mixers and ultrasonic mixers; this equipment is now collecting dust in our warehouse. Same method many have tried in making standard emulsions and nanoemulsions. However, this is not to say that medium- or even high- shear mixers may not be used in certain method embodiments of the present disclosure; it’s just that they are no longer necessary due to the HLD methodology. To beabsolutely clear on this point, any mixing device or technique that accomplishes the job may be employed, or combination thereof.

[0064] Compositions and methods of the present disclosure address the critical industry issue of thermodynamically stable fuel microemulsions by introducing innovative thermochemical HLD-based compositions and processes, including one or more algorithms for calculating HLD or HLD-NAC for their production. The compositions and methods of the present disclosure not only mitigate the challenges posed by HLB- based compositions and methods but also offer a sustainable approach to reduce disposal costs while promoting efficient engine combustion.

[0065] HLD Formulation Methodology

[0066] The present disclosure describes novel fuel microemulsions and methods for producing same using HLD, coupled with light, non-intense mechanical mixing (or higher intensity mechanical mixing, if desired or required). The HLD Equation is as follows (from Prof. Steven Abbott, Surfactant Science: Principles in Practice (2017)): HLD = F(S) - k.EACN - α(T-25) + Cc Where: EACN = Effective Alkane Carbon Number, i.e. the oiliness of the oil T - the Temperature, in °C S - the Salinity g / 100ml Cc - a Characteristic value for the hydrophobic / philic nature of the surfactant.

[0067] The HLD equation informs us that:

[0068] as S increases, HLD increases; the F(S) means "a function of Salinity" - for ethoxylates it is 0.13*S, for “other” (typically sorbitan monooleates and alkyl polyglucosides (APGs)) there is basically no S-dependence, and for ionics it is ln(S+SurfSal). Because an ionic surfactant adds to the salinity (the rule of thumb is that it is equivalent to 30 percent of its molar equivalent toNaCl) the percent Surfactant and its MWt combine to create a new total salinity.

[0069] as EACN increases (more oily) HLD decreases (the factor k typically varies from 0.15-0.17 depending on the surfactant, but for extended surfactants it's ~0.06). Use 0.16 as a default.

[0070] For ionics, α = 0.01, for ethoxylates α = -0.06 and for sugar surfactants such as APGs, α can be as low as -0.003 but not zero. So, as T increases above the reference value of 25°C, HLD decreases by 0.01 for each degree for ionics, increases by 0.06 for each degree for ethoxylates, and is nearly unchanged for APGs.

[0071] A high Cc means a large HLD.

[0072] Either iterative or non-iterative algorithms may be used to calculate HLD for a given system. One non-iterative algorithm is the algorithm explained by Johns et al., U.S. Pat. No.10,975,288. An iterative method is illustrated in FIG.4, which illustrates one method embodiment 100 for making a thermodynamically stable fuel microemulsion, the method comprising (box 102): a) providing a base fuel substantially in liquid phase (box 104); b) selecting a first surfactant package (box 106); c) providing water having a resistivity ranging from about 0.02 Megaohm^cm to about 18 Megaohm^cm (in certain embodiments ranging from about 0.02 Megaohm^cm to about 0.10 Megaohm^cm, or ranging from about 0.10 Megaohm^cm to about 1 Megaohm^cm, or ranging from about 1 to about 18 Megaohm^cm, or ranging from about 1 to about 10 Megaohm^cm), at 25^C, and in certain embodiments having substantially no particulate matter and / or known salinity (preferably about 20 mg / kg or less) and / or pH ranging from about 6.0 to about 8.0 (or from about 6.5 to about 7.5) (box 108);d) providing required input parameters of the base fuel, the first surfactant package, and the water to calculate hydrophilic-lipophilic difference (HLD) if the base fuel, the selected surfactant package, and the water were gently mixed (box 110); e) calculating a first hydrophilic-lipophilic difference (HLD1) using the required input parameters and a selected iterative HLD calculation algorithm (box 112); f) if the HLD1 is within a range of HLD ranging from about -0.5 to about +3, proceed to mix the base fuel, the first surfactant package, and the water (preferably, but not limited to, using a low energy, low footprint static mixer) to produce a thermodynamically stable, self-healing and / or self-assembling fuel microemulsion (box 114); and g) if the HLD1 is not within a range of HLD ranging from about -0.5 to about +3, select a second surfactant package to calculate a second hydrophilic-lipophilic difference (HLD2) using the required input parameters and the selected iterative HLD calculation algorithm (box 116).

[0073] The compositions and methods of the present disclosure may be produced at a temperature ranging from about 0 ºC to about 100 ºC, or from about 37 ºC to about 90 ºC, or from about of 37 ºC to about 41 ºC, and pressures ranging from sub-atmospheric up to 2,000 psi or more, or up to 1,000 psi or more, or up to about 50 psi or more, or up to atmospheric pressure, ensuring the compositions remain substantially liquid. Importantly, the methods of the present disclosure only require high temperatures if the base oil (for example, heavy fuel oil, or HFO) has a high viscosity at lower temperatures. High temperatures are to be avoided to avoid thermal degradation of surfactants and other additives. Polymers commonly added to fluids for rheological control can undergo thermal degradation at high temperatures, leading to a loss of their effectiveness in maintaining fluid stability. Components like emulsifiers, surfactants, and additives used in oil-based fuel microemulsions may undergo thermal decomposition at elevated temperatures, resulting in phase separation of aqueous and non-aqueous phases. Table 3 shows the degradation and decomposition temperature ofsurfactants that may be useful in certain fuel microemulsion embodiments. The solubility of various compounds in the fuel microemulsions can change with temperature, such as salts in the internal phase of the fuel microemulsions by precipitation of certain compounds that were previously dissolved in the fuel microemulsions. Changes in the concentration of dissolved ions can affect the charges on water droplets leading to increased absorption of water and thereby resulting in separation of the hydrocarbons in the fuel microemulsions.

[0074] HLD-NAC Formulation Methodology

[0075] The HLD helps identify potential compositions that can produce single-phase water-in-fuel microemulsions, but it does not predict the proportions of surfactant, water, and fuel that one can achieve with a given formulation. The Net-Average Curvature (NAC) uses the value of HLD, and the molecular geometry of surfactants and oil (fuel) to predict the proportions of surfactants, oil and water that can produce single phase microemulsions [See ref1, ref2, in the “References” list herein]. One example algorithm of the HLD-NAC methodology is included in FIG.5.

[0076] Block NAC_0 indicates the input variables required to implement the methodology. For the system input one needs the temperature (T, ranging from -20 to +100 ^C), the salinity of the system (S, expressed in grams of NaCl / 100 mL, preferred salinity is S = 0), the volume fraction of the surfactant (φs, preferred values being 0.05 or below), the volume fraction of water (φw, preferred values ranging from 0.05 to 0.15), the surfactant parameters k (ranging from 0.1 to 0.2), b (ranging from 0 to 0.2), α (ranging from 0.01 to -0.06, preferred values being close to or equal to zero), the molecular volume of the oil (fuel) vmo (Å3 / molecule), the characteristic curvature of the surfactant Cc (ranging from -6 to +8, in certain embodiments ranging from about -2 to about +6), the surfactant volume to neck area ratio vs / as(Å3 / Å2in certain embodiments ranging from 5 to 20, in certain embodiments ranging from about 7 to about 15), thesurfactant tail volume to neck area ratio vt / as (Å3 / Å2in certain embodiments ranging from 3 to 15, in certain embodiments ranging from 6 to 12), and the surfactant tail length parameter L (in certain embodiments ranging from 5 to 90 Å, in certain embodiments ranging from 15Å to 45Å). A table of HLD-NAC parameters is available in the literature [ref3], and the methods to obtain these parameters from phase scan experiments are also available in the literature [ref3, ref4].

[0077] In certain embodiments, the surfactant is a mixture of two or more surfactants. In certain exemplary embodiments, the mixture comprises one hydrophobic surfactant with high positive Cc (Cc> +3), with a large tail group (vt / as>8Å, L> 20 Å) and one balanced surfactant with intermediate Cc (-3<Cc<+3). The hydrophobic surfactant is used to improve the interactions with the oil phase, while the balanced surfactant is used to increase the water solubilization capacity in the fuel microemulsion. In other embodiments, a third hydrophilic surfactant (Cc<-3) can be used to adjust the water solubilization capacity in the microemulsion. For all these mixed surfactant systems, Block NAC_1 in FIG. 5 calculates the HLD-NAC properties for the surfactant mixtures. This block also includes the overlap factor theory (OFT) equation to calculate the characteristic length of the microemulsion ξ, which indicates the maximum capacity to co-solubilize water and oil in the microemulsion [ref1].

[0078] Block NAC_2 calculates the HDL-NAC variables for the system, including the value of HLD, the solubilization radius of water in the event that the aqueous phase becomes the continuous phase (Rwcont), the solubilization radius of oil in the event that the oil phase becomes the continuous phase (Rocont), the HLD boundary between water- continuous and bicontinuous microemulsions (HLDI-III), and the HLD boundary between bicontinuous and oil-continuous microemulsions (HLDIII-II). The HLD of the system, calculated in Block NAC_2 is compared against the HLDI-III in Block NAC_3. If HLD < HLDI-III, then the water is the continuous phase, which is incompatible with the disclosed compositions. Block NAC_4 is used to calculate the oil and watersolubilization radii (Ro, Rw) for that condition. The desirable compositions have HLD > HLDI-III. Block NAC_5, which only applies to systems with HLD > HLDI-III, compares asks if HLD > HLDIII-II, and if the answer is no, then the system is a bicontinuous microemulsion, one preferred composition of the present disclosure, and block NAC_6 is used to calculate the solubilization radii for oil and water in those cases (Ro, Rw). If HLD > HLDIII-II, then the system produces reverse micelles containing solubilized water, which is an acceptable form of water in fuel microemulsions, and the solubilization radii of oil and water (Ro, Rw) for those systems is calculated in Block NAC_7. Block NAC_8 calculates the lower and upper limits (LL, UL) of the system. These LL and UL limits represent the fraction of the height of the vial occupied by the microemulsion. Compositions of the present disclosure have LL = 0 and UL = 1, which represent single-phase microemulsion systems. Table 3 - Degradation and decomposition temperature of surfactants used in fuel microemulsions Surfactant Degradation Temperature (Approx.)° °

[0079] Benefits of Hydrophilic-lipophilic difference (HLD)

[0080] The hydrophilic-lipophilic difference technology offers a range of significant benefits for producing thermodynamically stable fuel microemulsions.

[0081] Referring now to the drawing figures, FIG.1 schematically illustrates a water in fuel macroemulsion; FIG.2 schematically illustrates a water in fuel microemulsion of the present disclosure; and FIG.3 is a graphical representation of the phase diagram presenting the relationship between oil, water, and surfactant phase diagram, indicating the region where a fuel microemulsion of base fuel (oil), water, and surfactant exists.

[0082] With respect to the compositions of the present disclosure, EACN for liquid fuels I have worked with range from about 6 to about 24.

[0083] Actual Blending ratios: Vol. % (broad Vol. % (narrow Actual Blending Ratios range) range) B il f l 55 t 95 75 t 90

[0084] During the creation of HLD microemulsions, a selection of surfactants with targeted Cc values are used, strategically combining them with selected fuels possessing specific characteristics, and at temperatures mentioned herein, depending largely on the beginning viscosity of the base fuel. This meticulous process yields a near self-assembled (low energy agitation) microemulsion that exhibits a near clear or clear single-phase solution for light fuels, and unparalleled thermodynamic stability. The combination of ingredients and process steps aims to achieve an aggregate HLD value = zero or near zero. As a result, the resulting mixture adopts a bicontinuous structure without distinct droplets. Notably, the formulation allows for the seamless addition of additives such as pour point suppressants and / or cetane improvers without disrupting the microemulsion's integrity. In certain embodiments, the methods of the present disclosure utilize a blending process that relies on mere static mixing to comingle the base fuel, water, and mixed surfactant package through a small footprint blending apparatus that can be self-contained with continuous monitoring and dosing equipment. The blending can be integrated within existing infrastructure not limited to a fuel terminal, on board a ship, within a power plant, within a fracking pump skid, trailer mounted or even integrated within the engine package itself.

[0085] The advanced mixed surfactant packages of the present disclosure can be easily tailored to suit different industry needs without requiring any engine modifications or retrofits. They may be designed to meet market demands for shelf- life and compatibility with base fuels, allowing for adjustments in parameters like cetane improvement, lubricity, viscosity, density, antioxidants, and biocides for long-term storage. Additionally, they address factors such as flash point, heat of combustion, and work output enhancements, ensuring practical versatility to meet various industry requirements. In addition, the fuel microemulsions of the present disclosure are compatible with industry fuel standards not limited to ASTM andISO fuel standards, including cold temperature parameters such as cloud point, pour point and cold filter plugging point.

[0086] In summary:

[0087] Use of high shear, ultrasonics, or other high-intensity, high-energy mixing techniques can achieve small water droplet size, and this was formally required to drive longer stability when employing HLB techniques. However, these emulsions are not thermodynamically stable so these techniques and macroemulsions (or nanoemulsions) cannot be used in the present market due to operating conditions.

[0088] The lower the HLB for water in oil emulsions the better. For this to be useful, more than one surfactant is often used, each having a different HLB value, and they must be aggregated to arrive at a total HLB number that only addresses the surfactants, not the hydrocarbon, not the water, not temperature or pressure. These HLB-based processes have been known for decades. Even HLB-based nanoemulsions are not thermodynamically stable under changing temperature conditions.

[0089] The coalescence of droplets occurs at changing temperature conditions, now the emulsion droplets are larger and can become visually opaque and now macroemulsion. Instability occurs, and emulsion droplets are not reversed to original state.

[0090] On the other hand, HLD utilizes Cc values of the surfactants, and the base fuel EACN value (approximately 9.7 ULSD and 8.5 for MGO). These need to be matched to a particular value to produce a microemulsion. In certain embodiments only two chemicals and soft emulsification are employed, targeting HLD of nearzero, with an ideal target of zero. No high energy mixing is required for the formation of the fuel microemulsions of the present disclosure, although as explained herein, any mixing technique may be used, even high-intensity or high- shear mixing. The beauty of the present compositions and methods is that simplified mixing is all that is required.

[0091] Nanoemulsions, through previous decades of trying, proved to be unstable, and experienced issues with temperature applications, were more expensive, requiring high energy mixing, and exhibited fuel filtration issues similar as macroemulsions.

[0092] While there is no standard design for mechanical equipment used to generate the fuel microemulsions of the present disclosure, given the numerous possible combinations of mixers, tubing lengths, tubing diameters, metallurgy, thickness, connectors, and the like, the following example provides insight into the process equipment and methods, operating parameters, features and limitations that factor into HLD-based fuel microemulsion processing.

[0093] Since there is no advantage in higher pressures to promote fuel microemulsion formation, the length of tubing from supply tanks to static mixers, and from static mixers to product tanks, should be kept to the minimum length to minimize heat losses to the environment, cost of power, and cost of equipment, keeping the footprint low, reduce repairs / maintenance and well intervention costs. If greater residence time is required, the length of tubing could be increased and / or increase the diameter of the tubing.

[0094] Pumping pressures are significantly lower in the methods of the present disclosure as the pump is only required to overcome friction losses in the feed tubing and static mixer, and product tubing. No high pressure pumping is required.

[0095] Static mixers, if used, may be blade type, helix type, wafer type, or any other type of low-energy mixer, including a simple impeller. Static mixers are available commercially from several sources, including Koflo Corporation (Cary, Illinois); Komax Systems, Inc. (Huntington Beach, California); Sulzer; and Statiflo Corporation, Pittsfield, Massachusetts. In certain embodiments, ultrasonic mixers, high-pressure emulsification mixers, and hydrodynamic cavitation systems may be employed. High- shear mixers are available commercially from various sources, including Quadro Engineering Corp., Waterloo, Ontario, Canada; Charles Ross & Son Company, Hauppauge, New York; and Schold, Chicago, Illinois; Silverson; and Admix. HLD-NAC Phase Scan Examples

[0096] Example 1. HLD-NAC phase scan for a water-in-diesel microemulsion with sorbitan monooleate and nonylphenol ethoxylate surfactant

[0097] In this example, a water in fuel microemulsion was formulated using a mixture of two surfactants, sorbitan monooleate as hydrophobic surfactant with a characteristic curvature (Cc) = +5.4, and a balanced surfactant penta-ethoxylated nonylphenol (IGEPAL CO-520 or NPE5) with Cc = +1.3. The formulation scan presented in FIG.6 was conducted using dyed diesel oil with an EACN = 9.68, deionized water. The formulation was conducted at room temperature (T=25°C) with a total water volume fraction of φw = 0.14 and a total surfactant volume fraction of φs = 0.04. The sorbitan monooleate, NPE5 and water were added to the vials in that sequence, followed by the addition of the required amount of diesel oil. The vials were then heated to 70°C for 30 minutes and then vortex-mixed at that temperature. The mixing temperature has to be at least 40°C to incorporate the viscous hydrophobic surfactant into the oil phase. The mixture was then cooled down to room temperature, vortex-mixed at room temperature, and left to equilibrate for one day before the photograph of FIG.6 was taken. The vials were observed for six months without any noticeable phase change. The proportion ofsorbitan monooleate and NPE5 varied from vials 1 through 9 as indicated in FIG.6. In vial 1, the surfactant mass proportion was 86 parts of NPE5 for 14 parts of sorbitan monooleate, and vials 2-9 used 87 / 13, 88 / 12, 89 / 11, 90 / 10, 91 / 9, 92 / 8, 93 / 7, and 94 / 6 NPE5 / sorbitan monooleate ratios, respectively.

[0098] The photographs in FIG.6 illustrate the complexity of producing single-phase water in fuel microemulsions. Even though all the vials contained the same total amount of surfactant, they all contained the same oil, the same surfactants, and in all cases, the HLD is within the desirable range, from +0 to +0.34, not all the vials resulted in single-phase microemulsions. The HLD-NAC predicted microemulsion limits, LL being the double solid line, and UL being the single solid line shown superimposed on the photo of the vials, allows one to narrow the formulation space to systems that are likely to produce the desired single-phase microemulsions. The HLD-NAC lines were produced using the algorithm of FIG.5 with the input data shown in the Table of FIG. 6. The photograph of the phase scan in FIG.6 shows that the composition of vial 5 (90 parts NPE5 / 10 parts sorbitan monooleate) produces a single-phase water-in-fuel microemulsion, as predicted by the HLD-NAC model.

[0099] A surprising observation, which could not be predicted by the HLD-NAC, is that when either the hydrophobic surfactant (the sorbitan monooleate in this example) or the balanced surfactant is a polyhydric alcohol with three or more hydroxyl groups, the formulation can maintain the single-phase system over a range of temperatures that is wider than that predicted by the HLD-NAC term α(T-25°C), where the α term for surfactant mixtures is calculated using the standard linear mixing rule considering the molar fraction of each surfactant in the surfactant mixture. This unexpected increase in thermal stability is an advantageous feature of the disclosed compositions.

[0100] Example 2. HLD-NAC ternary phase diagram for a water-in-diesel microemulsion with sorbitan monooleate and nonylphenol ethoxylate surfactant

[0101] The phase scan of Example 1 led to the specific proportion of 90 parts of NPE5 and 10 parts of sorbitan monooleate. To explore the relative proportions of total surfactant, diesel and water, the formulations listed in Table 4 were prepared at room temperature using the protocol explained in Example 1. Systems that produce single- phase microemulsions were noted, and systems that produced emulsions or multiple separate phases were noted as emulsions. The location of those formulations in the ternary phase diagram is noted in FIG.3, along with the HLD-NAC prediction of the single phase-multiple phase boundary, noted as a dashed line. Table 4. Composition of formulations in the ternary phase diagram (FIG.3) mg sorbitan mg µL µL Single emulsion l NPE i l E120 1080 1600 1200

[0102] The HLD-NAC dash line in FIG.3 was produced using a ternary phase diagram algorithm previously introduced in the literature [ref5]. The algorithm shows that for the NPE5 / sorbitan monooleate mixture at a 90 / 10 proportion, a total water to surfactant ratio of 2.5 can be achieved. This is an important property of the formulation for economic and efficiency reasons. The cost of surfactants can be 10 times larger than the cost of most fuels, which makes it a competitive advantage to produce compositions that can achieve high water to surfactant ratios.

[0103] The work of Neto et al. [ref6] includes a ternary phase diagram indicating the formulation of microemulsions with NPE5 and diesel. The authors did not use HLD nor HLD-NAC to arrive at their composition, and their system can only achieve a water to surfactant ratio of 1.1. The complexity of formulating these microemulsion systems is illustrated in the fact that the addition of only 10 parts of the hydrophobic surfactant sorbitan monooleate to 90 parts of the balanced surfactant NPE5 increased the water to surfactant ratio from 1.1 to 2.5. A defining feature of the formulations obtained via the HLD-NAC formulation method is that water to surfactant ratios of 2 or higher are obtainable. REFERENCES

[0104] Ref1 Acosta, E. J.; Harwell, J. H. Net-Average Curvature (NAC) Fundamentals. In Surfactant Formulation Engineering using HLD and NAC; Acosta, E. J., Harwell, J. H., Sabatini, D. A., Eds.; Cambridge, MA: Cambridge, MA, 2025; pp 259–325.

[0105] Ref2 Acosta, E. J.; Szekeres, E.; Sabatini, D. A.; Harwell, J. H. Net-Average Curvature Model for Solubilization and Supersolubilization in Surfactant Microemulsions. Langmuir 2003, 19 (1), 186–195.

[0106] Ref 3 Acosta, E.; Perez-Franco, R.; Zhuotao, L.; Cordeiro, B.; Tan, J. X.; Boza-Troncoso, A.; Hammond, C.; Zarate-Muñoz, S.; Harwel, J. The Hydrophobicity of Surfactants and Surfactant-Oil-Water (SOW) Systems. In Surfactant Formulation Engineering using HLD and NAC; Acosta, E. J., Harwell, J. H., Sabatini, D. A., Eds.; Academic Press: Cambridge, MA, 2025; pp 1–48.

[0107] Ref4 Zarate-Muñoz, S.; Texeira De Vasconcelos, F.; Myint-Myat, K.; Minchom, J.; Acosta, E. J. A Simplified Methodology to Measure the Characteristic Curvature (Cc) of Alkyl Ethoxylate Nonionic Surfactants. J. Surfactants Deterg. 2016, 19 (2), 249–263.

[0108] Ref5 Nouraei, M.; Acosta, E. J. Predicting Solubilisation Features of Ternary Phase Diagrams of Fully Dilutable Lecithin Linker Microemulsions. J. Colloid Interface Sci.2017, 495, 178–190.

[0109] Ref6 Neto, Afonso Avelino Dantas et al. “Brazilian Journal of Chemical Engineering alternative fuels composed by blends of nonionic surfactant with diesel and water : engine performance and emissions.” (2011).

[0110] From the foregoing detailed description of specific embodiments, it should be apparent that patentable fuel microemulsions, surfactant package(s), methods of making fuel microemulsions, and other aspects have been described. Although specific embodiments of the disclosure have been described herein in some detail, this has been done solely for the purposes of describing various features and aspects of the compositions, methods and systems, and is not intended to be limiting with respect to their scope. It is contemplated that various substitutions, alterations, and / or modifications, including but not limited to those implementation variations which mayhave been suggested herein, may be made to the described embodiments without departing from the scope of the appended claims.

Claims

What is claimed is:

1. A thermodynamically stable fuel microemulsion comprising: a) a base fuel substantially in liquid phase; b) a surfactant package; and c) water having a preferred resistivity ranging from about 0.02 Megaohm^cm to about 18 Megaohm^cm, at 25^C, wherein the surfactant package comprises one or more surfactants selected based on hydrophilic-lipophilic difference (HLD) of a mixed combination of the base fuel, the surfactant package, and the water, where the HLD ranges from about -0.5 to about +3, the HLD indicating thermodynamic stability.

2. The thermodynamically stable fuel microemulsion of claim 1 wherein the HLD ranges from about -0.5 to about +2.

3. The thermodynamically stable fuel microemulsion of claim 1 wherein the HLD ranges from about -0.5 to about +1.

4. The thermodynamically stable fuel microemulsion of claim 1 wherein the HLD ranges from about -0.5 to about +3.

0.

5. The thermodynamically stable fuel microemulsion of claim 1 wherein the HLD ranges from about -0.5 to about +2.

0.

6. The thermodynamically stable fuel microemulsion of claim 1 wherein the HLD ranges from about -0.5 to about +1.

0.

7. The thermodynamically stable fuel microemulsion of claim 1 wherein the HLD is 0.

8. The thermodynamically stable fuel microemulsion of claim 1 wherein the base fuel is selected from water-free hydrocarbons and biobased fuels, in part or in whole, wherein the hydrocarbons are selected from gasolines, diesel fuels, marine gas oils, marine diesel oils, biodiesel fuels, biomass diesel fuels, renewable fuels, synthetic fuels, light fuel oils, heavy fuel oils, kerosene fuels, aviation fuels, and wherein the biobased fuels are selected from biofuels, e-fuels, and algae- fuels, and hydrosols containing hydrocarbon fuels supplemented with water, and mixtures and combinations of any two or more of these.

9. The thermodynamically stable fuel microemulsion of claim 1 wherein the surfactant package is selected from one or more short chain and / or long chain non-ionic and / or ionic surfactants selected from nonylphenol ethoxylate, sorbitan esters, alkyl polyglucoside, sodium dioctyl sulfosuccinate, tridecyl alcohol ethoxylate, ethyl hexanol, 2-ethyl-hexyl nitrate, biocides, lubricity improvers and / or fuel dyes.

10. The thermodynamically stable fuel microemulsion of claim 1 wherein the base fuel is selected from gasolines, diesel fuels, marine gas oils, marine diesel oils, biodiesel fuels, renewable diesel and light fuel oils, and the fuel microemulsion is clear and transparent, with the proviso that when the base fuel is a heavy marine fuel such as HFO fuel (Heavy Fuel Oil), visual appearance is dark black.

11. The thermodynamically stable fuel microemulsion of claim 1 wherein the base fuel comprises a blend of two or more base fuels.

12. The thermodynamically stable fuel microemulsion of claim 1 wherein the base fuel comprises a blend of 80 volume percent marine diesel and 20 volume percent biodiesel.

13. The thermodynamically stable fuel microemulsion of claim 1 wherein the base fuel comprises a blend of 50 volume percent ultra-low sulfur diesel and 50 volume percent renewable diesel.

14. A method of making a thermodynamically stable fuel microemulsion, the method comprising: a) providing a base fuel substantially in liquid phase; b) selecting a first surfactant package; c) providing water having a preferred resistivity ranging from about 0.02 Megaohm^cm to about 18 Megaohm^cm at 25^C; d) providing required input parameters of the base fuel, the first surfactant package, and the water to calculate hydrophilic-lipophilic difference (HLD) if the base fuel, the selected surfactant package, and the water were gently mixed; e) calculating a first hydrophilic-lipophilic difference (HLD1) using the required input parameters and a selected iterative HLD calculation algorithm; f) if the HLD1 is within a range of HLD ranging from about -0.5 to about +3, proceed to mix the base fuel, the first surfactant package, and the water using a mixer to produce a thermodynamically stable, self-healing and / or self-assembling fuel microemulsion; g) if the HLD1 is not within a range of HLD ranging from about -0.5 to about +3, select a second surfactant package to calculate a second hydrophilic-lipophilic difference (HLD2) using the required input parameters and the selected iterative HLD calculation algorithm.

15. The method of claim 14 wherein the mixing occurs at a temperature ranging from about 0 ^C to about 100 ºC.

16. The method of claim 14 wherein the mixing occurs at a temperature ranging from 37 ºC to about 90 ºC.

17. A surfactant package useful in producing thermodynamically stable fuel microemulsions when combined with a base fuel and water using mixing, the surfactant package comprising: a) a surfactant selected from one or more short chain and / or long chain non- ionic and / or ionic surfactants, and mixtures and combinations thereof; b) a monohydroxy alcohol having from 6 to 10 carbon atoms; c) a nitrate cetane number enhancer having from 6 to 10 carbon atoms; d) optionally a biocide; e) optionally a lubricity improver; and f) optionally a fuel dye, wherein the surfactant is selected based on hydrophilic-lipophilic difference (HLD) of a mixed combination of a base fuel, the surfactant package, and water, where the HLD ranges from about -0.5 to about +3, the HLD indicating thermodynamic stability.

18. The surfactant package of claim 17 wherein the surfactant is selected from a nonylphenol ethoxylate, sorbitan esters, alkyl polyglucosides, sodium dioctyl sulfosuccinate, tridecyl alcohol ethoxylate, and mixtures and combinations thereof.

19. The surfactant package of claim 17 wherein the monohydroxy alcohol is ethyl hexanol.

20. The surfactant package of claim 17 wherein the nitrate cetane number enhancer is 2-ethyl-hexyl nitrate.

21. The surfactant package of claim 17 wherein the biocide is selected from, but not limited to isothiazolinones, oxazolidines, boron based chemicals, thiocyanates,morpholines, oxaborinanes, thiocarbamates, phenolic antioxidants, and mixtures and combinations thereof.

22. The surfactant package of claim 17 wherein the lubricity improver comprises one or more esters of an unsaturated monocarboxylic acid and a polyhydric alcohol.

23. The surfactant package of claim 22 wherein the one or more esters of an unsaturated monocarboxylic acid and a polyhydric alcohol comprises (a) an ester of an unsaturated monocarboxylic acid and a polyhydric alcohol, and (b) an ester of a polyunsaturated monocarboxylic acid and a polyhydric alcohol having at least three hydroxy groups, the esters (a) and (b) being different.

24. The composition of claim 23, wherein (a) is an ester of a polyhydric alcohol having at least three hydroxy groups.

25. The composition of claim 23 wherein (b) is an ester of polyhydric alcohol having at least three hydroxyl groups and wherein the polyhydric alcohol of each of (a) and (b) is a saturated, aliphatic, straight claim alcohol having 3 or 4 hydroxyl groups and 3 or 4 carbon atoms.

26. A thermodynamically stable fuel microemulsion comprising: a) a base fuel substantially in liquid phase; b) a hydrophobic surfactant with a characteristic curvature (Cc) of +3 or higher, with a tail volume / neck area ratio (vt / as) of 7Å or higher, and a tail length parameter (L) of 20 Å or higher;c) a balanced surfactant with a characteristic curvature (Cc) between -3 and +3, with a tail volume / neck area ratio (vt / as) of 5Å or higher, and a tail length parameter (L) of 20 Å or higher; and d) water having a resistivity ranging from about 0.02 Megaohm^cm to about 18 Megaohm^cm at 25^C.

27. The thermodynamically stable fuel microemulsion of claim 26, wherein the microemulsion has a water solubilization capacity of at least 2 / 1 water to surfactant (W / S) volume ratio.

28. The thermodynamically stable fuel microemulsion of claim 26, wherein the hydrophobic and the balanced surfactants are nonionic surfactants.

29. The thermodynamically stable fuel microemulsion of claim 26, wherein the hydrophobic and the balanced surfactants do not contain sulfur, nitrogen or phosphorus in their molecular structure.

30. The thermodynamically stable fuel microemulsion of claim 26, wherein the ratio between the mass of the hydrophobic and the balanced surfactants (HPH / BAL) that can be as low as 0.8 times the minimum HPH / BAL ratio predicted by the HLD-NAC model to generate a single phase microemulsion or as high as 1.2 times the maximum HPH / BAL ratio for single phase microemulsion predicted by the HLD-NAC model.

31. The thermodynamically stable fuel microemulsion of claim 26, wherein the composition comprises one or more additional surfactants that are hydrophilic, with a characteristic curvature (Cc) that is more negative than -3.

32. The thermodynamically stable fuel microemulsion of claim 26 wherein the water resistivity ranges from about 0.10 Megaohm^cm to about 1 Megaohm^cm.

33. The thermodynamically stable fuel microemulsion of claim 26 wherein the water resistivity ranges from about 1 Megaohm^cm to about 18 Megaohm^cm.

34. The thermodynamically stable fuel microemulsion of claim 26 wherein the water resistivity ranges from about 1 Megaohm^cm to about 10 Megaohm^cm.

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