Aqueous carbonaceous slurry fuel

Abstract

A direct injection, compression ignition, or diesel engine fuel comprising a mixture of 25 to 70 wt% finely ground carbonaceous particles, 5 to 40 wt% ammonia, and a residue containing an aqueous solvent, wherein the carbonaceous particles are derived from coal-based materials, biomass, charcoal, or mixtures thereof.

Description

Technical Field

[0001] Cross - reference to Related Applications This application claims the priority of Australian Provisional Patent Application No. 2023901705, filed on May 31, 2023, the content of which should be understood to be incorporated herein by reference.

[0002] The present invention generally relates to an aqueous carbonaceous slurry fuel for use in diesel - type engines. One exemplary use is for use as a fuel for large diesel engines used in stationary power generation, marine propulsion, and locomotives. However, it should be recognized that the present invention should not be limited to that use and may be applicable to a variety of engines that can use, or are adapted to use, an aqueous carbonaceous slurry fuel.

Background Art

[0003] The following discussion of the background art of the present invention is intended to facilitate understanding of the present invention. However, it should be recognized that this discussion is not an admission or acknowledgment that any of the materials referred to are published, known, or part of common general knowledge as of the priority date of this application.

[0004] New technologies involve the use of alternative fuels to replace heavy fuel oil for diesel - type engines, such as carbonaceous aqueous slurry fuels or emulsion fuels. Carbonaceous aqueous slurry fuels typically comprise an aqueous colloidal suspension of finely - divided carbonaceous particles. Emulsion fuels or emulsified fuels are emulsions composed of water and a combustible liquid, such as an oil or fuel, for example, asphalt emulsion fuel.

[0005] Therefore, the properties of these slurry and / or emulsion-type fuels differ significantly from conventional diesel and fuel oils, specifically their very high viscosity and tendency to destabilize and precipitate, forming sludge. Thus, the use of such alternative fuels requires an understanding of the complex interactions between the fuel and the engine. Some of these interactions include:

[0006] Stability: Slurry and emulsion fuels are inherently unstable and have a strong tendency to destabilize both in storage tanks and piping, forming solid sludge. Therefore, stability is particularly important during transport, storage, and handling in fuel systems, including after preheating for use in engines.

[0007] Specific Energy: Previous research has primarily focused on achieving a high solid content (and therefore a high specific energy of the fuel) while producing fuel that is easily atomized in the engine. Higher solid content has several benefits, including increased fuel stability, reduced transport and storage costs, and increased engine efficiency, due to a reduced latent heat penalty from water in the slurry. However, these gains are offset by the strong negative effects of high specific energy in atomization and combustion, which can render the fuel unusable.

[0008] Atomization Characteristics: Effective atomization is essential to minimize fuel ignition delay and ensure complete combustion and extinction. Insufficient atomization results in large slurry droplets that delay ignition and lead to incomplete combustion. This can cause deposits of unburned fuel on the cylinder walls, which, along with erosion of the exhaust turbine and deposits of large char and ash particles in the exhaust system after combustion, lead to accelerated wear and ring clogging problems. Atomization generally deteriorates with increasing fuel viscosity (indicated by injection shear rate), requiring fuel preheating and / or dilution with water. However, the interaction between fuel properties and atomization has been reported only briefly in the prior literature.

[0009] Ignition and Combustion Characteristics: Diesel engines require fuel that ignites quickly (preferably less than 10 ms in large engines) to avoid a rapid pressure increase due to the spontaneous ignition of previously injected fuel. Residual fuel and coal tend to delay ignition longer than lighter fuels, such as marine gas oil. It is important to note that fuels that ignite well may not be highly flammable. For example, coal-diesel mixtures have similar ignition characteristics to diesel fuel. However, coal is less flammable because when dispersed in diesel (or other non-polar hydrocarbons), it aggregates, efficiently creating large, less flammable coal particles. Fuels containing such coal particles are very prone to depositing unburned carbon on the cylinder walls of engines, leading to prolonged wear of rings and liners.

[0010] Wear Characteristics: Engine wear includes fuel injectors, particularly injector nozzles, piston rings and cylinder liners, exhaust valve seats and turbocharger turbines and intake vanes. Prior literature assumes that wear is proportional to the total ash content of the fuel. The effect of higher ash content fuels (especially coal) is not well understood in published prior art. However, total ash can be an insufficient substitute for the abrasive properties of solid carbonaceous fuels, and some fuels with higher ash content form softer abrasive particles than those from fuels with lower ash content. With respect to coal, this erosive material largely originates from exogenous mineral particles, such as quartz, feldspar, and pyrite, which vary considerably in both quantity and mode of occurrence (mineral combination and particle size). This is further complicated by the preparation of fuels to produce carbonaceous slurry fuels, where, for example, some cleaning methods can reduce the amount of crude minerals but increase the proportion of fine minerals remaining in the fuel.

[0011] Ash adhesion characteristics: This involves the formation of high-temperature ash deposits by mineral and inorganic chemical species. During combustion, these form various oxide / sulfide / sulfate compounds that can form deposits on pistons, cylinder covers and exhaust valves, as well as in exhaust systems including turbocharged turbines and waste heat boilers.

[0012] Emission characteristics: CO2 and SOx emissions are roughly proportional to the C and S content of the carbon used to produce the fuel, with only a small contribution from dispersants used in the formulation (except for low-cost additives, e.g., lignosulfonates; which, when used typically at 1 to 2 wt% additive (based on dry coal), can cause a significant increase in the Na and S content of the fuel). [Prior art documents] [Patent Documents]

[0013] [Patent Document 1] International Patent Publication WO2013142921A1 [Patent Document 2] International Patent Publication WO2015048843A1 [Overview of the Initiative] [Problems that the invention aims to solve]

[0014] Therefore, it is desirable to provide new and / or alternative carbonaceous slurry fuels. [Means for solving the problem]

[0015] The present invention generates alternative aqueous carbonaceous slurry fuels for use in direct injection, compression ignition, or diesel-type engines through controlled formulations and / or blends of fuels that are not normally compatible. Thus, the fuels of the present invention possess a variety of advantageous fuel attributes that are not possible with single-component carbonaceous slurry fuels.

[0016] A first aspect of the present invention is: a. A mixture of 25 to 70 wt% finely ground carbonaceous particles. b. Ammonia in an amount of 5 to 40 wt%, and c. Residue containing aqueous solvent A direct injection, compression ignition, or diesel engine fuel, including Carbonaceous particles originate from coal-based materials, biomass, charcoal, or mixtures thereof. To provide fuel.

[0017] In embodiments, this direct injection, compression ignition, or diesel engine fuel (aqueous carbonaceous slurry fuel) comprises a mixture of pulverized carbonaceous particles and an aqueous solvent, preferably an aqueous solvent containing water, resulting in a carbonaceous material ratio in the range of 25 to 70 wt%, an ammonia ratio in the range of 5 to 40 wt%, and the remainder being an aqueous solvent (e.g., water, water-ethanol, water-methanol, water-sugar mixture / solution, etc.) and an optional amount of additives to control rheology, ignition, combustion, NOx formation, and ash properties.

[0018] A first aspect of the present invention provides a blended fuel comprising a blend mixture of an aqueous carbonaceous slurry fuel and an ammonia fuel. This blend can possess a variety of improved properties, including, but not limited to, reduced CO2, NOx, SOx, and ash buildup, reduced fuel system corrosion, and improved fuel stability and overall combustion performance. For example, the addition of ammonia to an aqueous slurry fuel enables the use of ammonia without the need for pressurized or depressurized storage, and / or the carbonaceous fuel improves the ignition and combustion of ammonia. Ammonia increases the specific energy of the fuel and reduces fuel system corrosion, CO2 and SOx emissions, ash buildup, and erosion caused by mineral ash in the carbonaceous fuel components. Ammonia also causes an increase in the pH of the fuel blend, imparting improved rheology to most carbonaceous materials in this blend.

[0019] It should be recognized that ammonia is first added to the fuel composition of the present invention to assist in reducing the CO2 formed during combustion and also to raise the pH of the fuel to assist in engine corrosion / protection. However, other advantages have also been found. Without wishing to be limited to one theory, the addition of ammonia to the slurry has been found to improve overall combustion in terms of shortening the ignition delay and the time taken for combustion measured from accurate measurements of cylinder pressure and crankshaft rotation. The inventor hypothesizes that this combustion improvement is due to the explosive evaporation of ammonia within the slurry droplets formed by atomization, thereby improving the atomization properties effective for a given fuel viscosity and injection conditions. For this reason, it has become possible to lower the injection pressure, and wear of the atomizer has also been reduced with a low injection rate.

[0020] The aqueous solvent may include any suitable aqueous solvent. In some embodiments, the aqueous solvent includes water. However, it should be recognized that some other aqueous solutions, such as water-ethanol, water-methanol, water-sugar mixtures / solutions are also conceivable.

[0021] The ammonia content of the fuel can be selected to provide the improved specific energy and / or improved properties discussed above. In an embodiment, the mass fraction of ammonia in the fuel mixture is from 10 to 40 wt%, preferably from 20 to 40 wt%. In other embodiments, the mass fraction of ammonia in the fuel mixture is from 5 to 30 wt%, preferably from 5 to 25 wt%. In still other embodiments, the mass fraction of ammonia in the fuel mixture is from 10 to 30 wt%, preferably from 15 to 25 wt%. In an embodiment, at atmospheric pressure, depending on the temperature of the fuel, up to 25 to 30 wt% can be added to the aqueous / water component of the fuel. It should be recognized that the ammonia content of the fuel exists as ammonium ions in the solution.

[0022] The mass fraction of carbonaceous particles in the fuel is determined by several factors including the size, composition, etc. of the particles. In some embodiments, the mass fraction of carbonaceous particles in the fuel ranges from 40 to 70 wt%, preferably from 45 to 70 wt% of the fuel. In other embodiments, the mass fraction of carbonaceous particles in the fuel ranges from 50 to 70 wt%, preferably from 50 to 60 wt%. In still other embodiments, the mass fraction of carbonaceous particles in the fuel ranges from 40 to 65 wt%, preferably from 45 to 60 wt%.

[0023] The carbonaceous particles can include several carbonaceous materials. In a slurry fuel, the carbonaceous particles are derived from coal-based materials, biomass, charcoal, or mixtures thereof. In some embodiments, the carbonaceous particles are derived from at least one coal-based material. In other embodiments, the carbonaceous particles include carbonaceous particles derived from 2 to 70 wt% of biomass or charcoal. Typically, the remainder of the carbonaceous particles is derived from coal-based materials. In embodiments, the remainder of the carbonaceous particles (in the first or second aspect of the present invention) can be selected from the group consisting of coal, charcoal, wood, various hydrocarbons, and organic substances whether essentially biological or organic compounds, etc.

[0024] In a specific aspect of the present invention, the first aspect of the present invention is a. A mixture of 25 to 70 wt% of micronized carbonaceous particles, b. 5 to 40 wt% of ammonia, and c. The remainder comprising an aqueous solvent comprising a direct injection, compression ignition, or diesel-type engine fuel, where the carbonaceous particles include carbonaceous particles derived from 2 to 70 wt% of biomass, charcoal, or carbon black, providing a fuel.

[0025] It should be understood that the carbonaceous particles in the fuel "originate" from coal-based materials, biomass, charcoal, or mixtures thereof, and that, in embodiments, such carbonaceous particle sources are mixed and blended to form the final blended mixture of carbonaceous particles. "Originate from" should be understood to mean that the carbonaceous particles are supplied from a specific carbonaceous particle type raw material. While the compositions of these sources may be similar and, in some cases, have compositional overlap, it should be recognized that the composition of the final blended mixture can still be understood as being traceable back to the carbonaceous particles constituting the specific carbonaceous particle source.

[0026] Any type of coal may be used, such as anthracite, bituminous coal, or lignite. This is particularly advantageous because coal is readily available as a carbonaceous source.

[0027] It should be understood that charcoal covers carbonaceous residues obtained by heating organic matter, such as woody plant materials, in processes involving carbonization, incomplete thermal decomposition, or gasification, or when carbonaceous materials are partially burned or heated with limited air access. Charcoal is a solid residue. Charcoal is a solid material that remains after light gases (e.g., coal gas) and tar have been displaced or released from the carbonaceous material during the initial combustion known as carbonization, charring, liquefaction, or thermal decomposition. One example is the partial combustion of wood or plant fibers.

[0028] It should be understood that biomass-derived carbonaceous particles cover carbonaceous by-products formed from incomplete biomass gasification, pyrolysis, or low-temperature carbonization and roasting of biomass sources. In this sense, biomass includes any organic matter supplied from living organisms, including plants and animals, and may include waste sources from such organisms. In embodiments, biomass includes organic plant matter. Biomass carbonaceous particles can originate from a variety of sources. In embodiments, biomass carbonaceous particles include carbonaceous by-products from incomplete biomass gasification, pyrolysis, or low-temperature carbonization and roasting.

[0029] A second aspect of the present invention is a direct injection, compression ignition, or diesel engine fuel comprising carbonaceous particles suspended in an aqueous solvent, 40 to 70 wt% carbonaceous particles, including 2 to 100 wt% carbonaceous particles derived from biomass or charcoal. Residue containing aqueous solvent It provides fuel, including

[0030] This second aspect of the present invention provides an aqueous slurry fuel based on an alternative carbonaceous particulate source selected from biomass or charcoal. This fuel formulation can advantageously possess a variety of improved properties, including, but not limited to, reduced CO2, NOx, SOx, and ash buildup, reduced corrosion, and improved fuel stability and overall combustion performance.

[0031] In some embodiments, the carbonaceous particles include 2 to 70 wt% of carbonaceous particles derived from biomass or charcoal. Typically, the remainder of the carbonaceous particles is derived from coal-based materials. In embodiments, the remainder of the carbonaceous particles may be selected from the group consisting of coal, charcoal, wood, various hydrocarbons, and organic materials, whether essentially biological or organic compounds.

[0032] These formulations may possess various improved properties, including, but are not limited to, improved resistance to microbial activity (such as mold formation), increased specific energy, and improved rheology, including stability and shearing behavior.

[0033] In some embodiments, the fuel further comprises 5 to 40 wt% ammonia, preferably 10 to 30 wt% ammonia, more preferably 20 to 40 wt% ammonia. As described in relation to the first aspect of the present invention, the addition of ammonia provides a variety of improved properties, including, but not limited to, reduction of CO2, NOx, SOx, ash buildup, reduction of fuel system corrosion, and improvement of fuel stability and overall combustion performance. Ammonia increases the specific energy of the fuel and reduces fuel system corrosion, CO2 and SOx emissions, ash buildup, and erosion due to mineral ash in the carbonaceous fuel components. Ammonia also results in an increase in the pH of the fuel blend, which imparts improved rheology to most carbonaceous materials in this blend. In some embodiments, the mass fraction of ammonia in the fuel mixture is 10 to 40 wt%, preferably 20 to 40 wt%. In other embodiments, the mass fraction of ammonia in the fuel mixture is 5 to 30 wt%, preferably 5 to 25 wt%. In yet another embodiment, the mass fraction of ammonia in the fuel mixture is 10 to 30 wt%, preferably 15 to 25 wt%.

[0034] In some embodiments, the carbonaceous fuel comprises an aqueous solvent containing a mixture of finely ground carbonaceous particles, preferably water and an optional additive. The mass fraction of the carbonaceous particles is in the range of 45 to 70 wt%, with the remainder being water and an optional amount of additive. In some embodiments, the carbonaceous particles include 2 to 70 wt% of carbonaceous particles derived from biomass or charcoal. The biomass may include, but is not limited to, carbonaceous by-products from incomplete biomass gasification and pyrolysis, as well as from low-temperature carbonization and roasting. In some embodiments, the carbonaceous fraction includes 10 to 70 wt% of biomass or charcoal, preferably 20 to 70 wt% of biomass or charcoal. In other embodiments, the carbonaceous fraction includes 5 to 60 wt% of biomass or charcoal, preferably 10 to 50 wt% of biomass or charcoal.

[0035] Furthermore, the aqueous solvent may include any suitable aqueous solvent. In some embodiments, the aqueous solvent includes water. However, it should be recognized that several other aqueous solutions, such as water-ethanol, water-methanol, and water-sugar mixtures / solutions, are also possible. In embodiments, the aqueous solvent includes water and an optional additive.

[0036] The resulting fuel is classified as a carbonaceous slurry because, at room temperature, its main combustible components (coal, charcoal, biomass, algal matter, and residual fuel oil) are solid, meaning it does not conform to the shape of the container.

[0037] Again, the mass fraction of carbonaceous particles in a fuel is determined by several factors, including particle size and composition. Typically, the mass fraction of carbonaceous particles in a fuel is in the range of 40 to 70 wt% of the fuel. However, in some embodiments, the mass fraction of carbonaceous particles in a fuel is 45 to 70 wt% of the fuel. In other embodiments, the mass fraction of carbonaceous particles in a fuel is in the range of 50 to 70 wt%, preferably 50 to 60 wt%. In yet another embodiment, the mass fraction of carbonaceous particles in a fuel is in the range of 40 to 65 wt%, preferably 45 to 60 wt%.

[0038] The carbonaceous particles of the first and second embodiments of the present invention may include some of the carbonaceous materials required above.

[0039] Biomass carbonaceous particles can originate from a variety of sources. In some embodiments, the biomass carbonaceous particles include carbonaceous by-products from incomplete biomass gasification, pyrolysis, or low-temperature carbonization and roasting.

[0040] In some embodiments, the carbonaceous fuel comprises a mixture of carbonaceous particles preferably derived from coal, biomass, or charcoal, with the remainder being an aqueous solvent, preferably water and an optional additive. In these embodiments, the carbonaceous particles comprise 2 to 70 wt% of carbonaceous particles derived from biomass or charcoal, with the remainder of the carbonaceous particles derived from at least one coal-based material. Any type of coal-based material, such as anthracite, bituminous coal, or lignite or charcoal, may be used. This is particularly advantageous because coal is readily available as a carbonaceous source.

[0041] The carbonaceous source preferably has a low ash content of less than 2 wt%, more preferably less than 1 wt%, and most preferably less than 0.5 wt%.

[0042] In cases where the carbonaceous particles are coal, it is preferable that the coal undergoes some form of pretreatment. Pretreatment may include the removal of most of the mineral ash contamination, and in the case of lower-grade coal, it may include some form of densification and modification of surface properties to make the coal more hydrophobic, enabling the realization of fuels with a higher coal content. For example, desalination of bituminous coal can be achieved by selective flocculation, flotation, and cycloning.

[0043] In this embodiment, the carbonaceous particles are hydrophobic. This is preferable because it improves the dispersion of the particles in the solvent.

[0044] The carbonaceous particles are preferably pulverized or finely ground particles. In terms of particle size, this typically requires carbonaceous particles having an average particle size of preferably less than about 30 μm by mass, and preferably about 20 μm or less by mass. In some embodiments, the average particle size is about 10 μm to about 20 μm by mass.

[0045] The upper size of carbonaceous particles is preferably about 3 to about 10 times larger than the mass-average diameter. The upper size / maximum size is understood to be the size that accounts for up to 5% of the population, and therefore may include much larger sizes, although the probability decreases. The upper size range is also known as d95, where its diameter is less than the diameter in which 95% of the mass is distributed. Thus, d95 is about 3 to about 10 times larger than the mass-average diameter. More preferably, the d95 of carbonaceous particles is about 4 to about 5 times larger than the mass-average diameter. It is recognized that adopting a larger size distribution ratio allows for an increase in the amount of solid filler for a given viscosity limit. For a given amount of solid filler, there is a strong inverse correlation between fuel viscosity and particle size distribution. Similarly, there is a reasonable correlation between viscosity and stability.

[0046] Preferably, when the carbonaceous particles have a mass-average particle size of 20 μm or less, the carbonaceous particles exhibit a wide size range, for example, from more than 0 μm to about 100 μm. More preferably, the carbonaceous particles exhibit a size range from more than about 1 μm to about 80 μm. Specifying a wide size range is advantageous because it improves the packing efficiency of coal particles in the fuel composition, thereby making it possible to produce fuel with a larger amount of carbonaceous particles. This is due to the smaller particles being able to fill the gaps between larger particles.

[0047] Alternatively, a fuel composition may be formed using multiple populations of carbonaceous particles having different size ranges. For example, the fuel may contain carbonaceous particles having a bimodal size distribution. In this case, the fuel contains a first population of carbonaceous particles having a first size distribution with respect to a first mass mean, and a second population having a second size distribution with respect to a second mass mean, where the first mass mean is less than the second mass mean. In this case, at least some of the particles in the first population are sized to fit into the gaps formed between the particles in the second population.

[0048] In a further example, the fuel may contain particles having a trimodal size distribution, in which case the fuel is as described above, but additionally includes a third population of carbonaceous particles having a third size distribution for a third mass mean. The third mass mean is smaller than the first mass mean, and as a result these particles are sized to fit into the gaps formed by the particles in the first and second populations.

[0049] As previously discussed, the particle d95 is about 3 to 10 times the mass-average size, preferably about 4 to 5 times the mass-average size. Preferably, in this case, the maximum size is about 200 μm, and it is noteworthy that the ratio to the maximum mass-average size is easily reduced by classification and re-grinding (i.e., closed-circuit grinding) to ensure that the coal can burn out during engine combustion time. As the maximum size increases, the particle size distribution naturally becomes wide enough to achieve high solid fill density, and smaller particles in the size distribution can fit into the gaps formed between larger particles in the size distribution.

[0050] Unless otherwise specified, it should be understood that all viscosities listed herein are as measured at (controlled) 25°C. It should also be recognized that the term “viscosity” is intended to refer to the obvious “dynamic viscosity,” also known as “shear viscosity,” and not “kinematic viscosity.” Preferred means for determining the viscosity of fuel will be readily apparent to those skilled in the art. However, a preferred means for determining viscosity is through the use of a rotational viscometer having a cylinder and cup over a shear rate range of 0.1 to 3000 per second. For higher shear stress measurements (above 3000 per second), an extrusion viscometer may be used.

[0051] The viscosity of the present invention (in both the first and second embodiments) is preferably generally a shear-thinning viscosity. Generally, a shear-thinning viscosity is one in which the slope of the viscosity-shear rate curve is usually negative. It should be recognized that the fuels of the present invention may still exhibit regions where the slope (slop) is positive (shear-thickening), and in these areas, conditioning (control of shear mixing) may be required to massage out such kinks. Therefore, "generally" shear-thinning should be understood as meaning that at high shear rates, the viscosity is lower on the right side of the viscosity-shear rate curve than on the left side, even if the viscosity-shear rate curve has an inflection point in the middle.

[0052] The fuels of the first or second embodiment of the present invention can be formulated to obtain a viable rheology within a wide range. In embodiments, the fuel may have an apparent viscosity (measured using a Kinexus rheometer) of less than 500 mPa·s at 100 / s and greater than 20,000 mPa·s at 0.1 / s. The fuel also preferably has a shear thinning of up to 100,000 / s in general. While we do not wish to limit ourselves to one theory, the above rheology is chosen as a viscosity of less than 500 mPa·s to ensure satisfactory injection and atomization behavior for engines operating at less than 1000 rpm. A viscosity greater than 20,000 mPa·s at 0.1 / s ensures good stability with little to no sedimentation over 90 days in undisturbed storage.

[0053] The fuel in the first or second embodiment may include a slurry alone, or may include one or more additives, including at least one of a dispersant, stabilizer, biocide, or a combination thereof.

[0054] In some embodiments, the fuel further includes a dispersant. The dispersant is important for maintaining the suspension of carbonaceous particles in the aqueous solvent. Preferably, the dispersant is selected from the group consisting of anionic dispersants that impart a negative charge and steric hindrance to the surface, nonionic dispersants that impart steric hindrance, or amphoteric dispersants that impart both negative and positive charges. More preferably, the anionic dispersant is selected from the group consisting of polystyrene sulfonates, polyisoprene sulfonates, carboxymethylcellulose, humic acid, polyacrylates, and sodium salts of copolymers of acrylic acid and other acrylic monomers; lignosulfonates, naphthalene sulfonates, or sodium or ammonium salts of naphthalene sulfonate formaldehyde condensates. More preferably, the nonionic dispersant is selected from the group consisting of cellulose ethers, e.g., hydroxyethylcellulose or hydroxypropylcellulose; polysaccharides, e.g., dextrin; polyoxyethylene sorbitan monooleate or rosin or saponin-based dispersants. More preferably, the amphoteric dispersant is a polycarboxylate.

[0055] The fuel may also include stabilizers, such as natural gums including guar gum, ransom gum, xanthan gum, and gellan gum, phosphates, or iron(II) sulfate.

[0056] The fuel may also contain biocides that reduce microbial activity, such as formaldehyde.

[0057] The fuel may further include, in addition or by other means, at least one additive that controls at least one of the properties of rheology, ignition, combustion and NOx formation, or ash. The at least one additive preferably includes, but is not limited to, a solution of "wood vinegar," and includes condensation by-products from the thermal decomposition and carbonization of biomass.

[0058] It should be recognized that the fuel of the present invention is suitable for use in the combustion chambers of compression-ignited or directly injected diesel engines. It should also be understood that diesel engines include any engines manufactured, constructed, or modified to operate using a fuel containing carbonaceous particles suspended in an aqueous medium. Thus, a particular engine may be a conventional compression-ignited or diesel engine, or an improved, modified, or otherwise derived engine from a conventional compression-ignited or diesel engine that operates using a fuel containing carbonaceous particles suspended in an aqueous solvent. One example is a diesel engine that is a direct-injection carbon engine (DICE), which has been modified to allow combustion of an aqueous slurry of micronised refined carbon fuel (MRC).

[0059] Other examples include diesel engines used in power generation, ships, and locomotives. In some embodiments, the fuel is used in stationary power generation engines. In these embodiments, the engine typically includes a large engine fixed in a building or other enclosed location, primarily used to generate electricity. In other embodiments, the fuel is used in transport engines, typically to propel ships. Examples of transport engines include the use of engines to power and propel locomotives, ocean-going vessels, such as ships, ocean liners, barges, etc. However, it should be recognized that other vehicle engines, such as trucks, can also utilize the fuel of the present invention to provide suitable, sized, and powered engines.

[0060] In another aspect of the present invention, the use of previously described fuels in a combustion chamber, for example, in an engine, such as a direct injection, compression ignition, or diesel engine. More preferably, the fuels are for use in a modified diesel engine, such as a diesel engine having a blast injector. Examples of certain preferred injector nozzles forming parts of a blast sprayer type injector are taught in International Patent Publications WO2013142921A1 and WO2015048843A1 by the same applicant, the contents of which should be understood to be incorporated herein by reference. In some embodiments, the diesel engines include power generation, marine, or locomotive engines.

[0061] A third aspect of the present invention is a method for preparing fuel for direct injection, compression ignition, or for directing fuel to the combustion chamber of a diesel engine, The process involves mixing carbonaceous particles and water to form a fuel mixture of carbonaceous particles suspended in water, wherein the carbonaceous particles are derived from coal-based materials, biomass, charcoal, or mixtures thereof. The process of adding ammonia to the fuel mixture, This process produces a fuel mixture containing a mixture of 25 to 70 wt% finely ground carbonaceous particles, 5 to 40 wt% ammonia, and a residue containing water. This provides a method that includes [something].

[0062] In slurry fuels, carbonaceous particles are derived from coal-based materials, biomass, charcoal, or mixtures thereof. In some embodiments, the carbonaceous particles are derived from at least one coal-based material. In other embodiments, the carbonaceous particles include 2 to 70 wt% of carbonaceous particles derived from biomass or charcoal. Typically, the remainder of the carbonaceous particles is derived from coal-based materials.

[0063] In embodiments of the present invention, ammonia may be added to the fuel at any point along the fuel production chain, after the formation of the slurry, including the water used to produce the slurry, during storage, or between the fuel storage tank and the engine injector valve nozzle orifice. For example, ammonia may be added to the water used to make the slurry, or to the slurry itself. In such embodiments, ammonia is added to the fuel mixture during storage of the fuel mixture; or at least one of the mixing regions between the fuel storage container and the injection of fuel in the engine injector. If the pressure is very high, additional ammonia may be added to the fuel system as the fuel enters the engine. The amount of ammonia in the fuel is as taught in relation to the first aspect of the present invention. Again, in embodiments, up to 25 to 30 wt% may be added to the aqueous / water component of the fuel, depending on the fuel temperature, using the fuel at atmospheric pressure. It should be recognized that the ammonia content of the fuel exists as ammonium ions in solution.

[0064] A fourth aspect of the present invention is a method for preparing fuel for direct injection, compression ignition, or for directing fuel to the combustion chamber of a diesel engine, The process includes blending carbonaceous particles and water to form a fuel mixture of carbonaceous particles suspended in water, The mass fraction of carbonaceous particles in the fuel mixture is 2 to 1000 wt% of carbonaceous particles derived from biomass or charcoal From which 40 to 70 wt% are selected, Provide a method.

[0065] In some embodiments, the carbonaceous particles in the fuel mixture include at least two different types of carbonaceous particles blended together, selected from 2 to 70 wt% of carbonaceous particles derived from biomass or charcoal, with the remainder being coal-based particles.

[0066] The blending process is preferably carried out at various points in the fuel delivery chain to the engine to achieve a consistent composition, avoid incompatibility, optimize required properties, and / or simplify the fuel production chain. Various carbonaceous particles may be blended in the engine, preferably immediately before use.

[0067] The blending process is preferably carried out to obtain a homogeneously mixed slurry fuel. In this regard, the blending process may be carried out with sufficient intensity and duration to ensure the homogeneity of the slurry fuel, and with sufficient intensity / duration / temperature combinations to avoid undesirable negative changes in the properties of the fuel (e.g., aggregation of coal particles). The blended fuel is handled in such a way that the effects of fuel incompatibility are reduced to an acceptable level by, for example, avoiding long durations at high temperatures or excessive shear, and blending intensities that could partially destabilize the slurry.

[0068] As in the third aspect of the present invention, the method of this fourth aspect may further include the step of adding 5 to 40 wt% ammonia to the fuel mixture. As described above, the addition of ammonia provides a variety of improved properties, including, but not limited to, reduction of CO2, NOx, SOx, and ash buildup, reduction of fuel system corrosion, and improvement of fuel stability and overall combustion performance. Ammonia increases the specific energy of the fuel and reduces fuel system corrosion, CO2 and SOx emissions, ash buildup, and erosion caused by mineral ash in the carbonaceous fuel components. Ammonia also results in an increase in the pH of the fuel blend, which imparts improved rheology to most carbonaceous materials in this blend.

[0069] In the fuel mixture, 2 to 70 wt% of carbonaceous particles are derived from biomass or charcoal.

[0070] The formulations described in the first and second aspects of the present invention can be achieved by blending consistent components at various points in the fuel delivery chain to the engine to avoid incompatibility, optimize required properties, and / or simplify the fuel production chain. This includes blending in the engine immediately before use.

[0071] A fifth aspect of the present invention provides a method according to the third or fourth aspect of the present invention, wherein the fuel mixture comprises a fuel according to the first or second aspect of the present invention.

[0072] Further aspects of the present invention, and further embodiments of the aspects described in the preceding paragraphs, will become apparent from the following descriptions provided as examples. [Modes for carrying out the invention]

[0073] The present invention relates to a carbonaceous aqueous slurry formulation for alternative fuels for large diesel engines for stationary power generation, ships, and locomotives. The carbonaceous slurry fuel of the present invention comprises carbonaceous particles suspended in an aqueous solution. Embodiments of the fuel of the present invention can be classified as one type of finely refined carbon fuel (MRC). Such fuels are formulated for use in engines, such as diesel engines, or modified diesel engines, such as direct injection carbon engines (DICE).

[0074] Numerous problems exist in using carbonaceous slurry-based alternative fuels and emulsion fuels in diesel engines, most of which are strongly related to and involved in the complex interactions between the fuel and the engine. While various strategies have been considered to overcome these problems, they have all missed the opportunity to use blended fuels that achieve optimal fuel properties and alleviate the limitations of individual fuels. The inventors surmise that this lack of investigation into the opportunities presented by selective formulations is a result of insufficient understanding of the complex phenomena affecting fuel-engine interactions for these composite alternative fuels.

[0075] While not wishing to be limited to a single theory, the inventors believe that accepted knowledge regarding slurry fuel formulations is questionable, and that several advantageous formulations with various improved fuel properties that can be optimized for end-use have been discovered. Surprisingly, the inventors have found that a variety of useful slurry fuels can be formed by blending significantly different carbonaceous fuels that have not been considered compatible in conventional knowledge, to produce slurry fuels with optimal properties including, but not limited by, stability in precipitation and resistance to microbial activity, as well as optimal specific energy, rheology, ignition characteristics, combustion characteristics, abrasion characteristics, CO2 and sulfur oxide and nitrogen oxide emission intensity, cost, and availability.

[0076] The present invention provides two main embodiments of blended fuels:

[0077] An embodiment of a first blended fuel comprising a blend mixture of aqueous carbonaceous slurry fuel and ammonia fuel, comprising a mixture of 25 to 70 wt% pulverized carbonaceous particles derived from coal-based materials, biomass, charcoal, or mixtures thereof; 5 to 40 wt% ammonia; and a residue containing an aqueous solvent. In certain embodiments, the carbonaceous particles may consist of 2 to 70 wt% carbonaceous particles derived from biomass or charcoal, and

[0078] An embodiment of a second blended fuel comprising a blend of an aqueous coal-based slurry fuel and an alternative carbonaceous particle source selected from biomass or charcoal, wherein the alternative carbonaceous particle source comprises carbonaceous particles suspended in 40 to 70 wt% aqueous solvent, consisting of 2 to 100 wt% carbonaceous particles derived from biomass or charcoal. In some embodiments, the carbonaceous particle source comprises a mixture of 2 to 70 wt% carbonaceous particles derived from biomass or charcoal, with the remainder of the carbonaceous particles derived from at least one coal-based material.

[0079] It should be recognized that the fuel formulations of the present invention can produce slurries with properties optimally suited to the required application by blending solids, slurries, emulsions, and other novel fuels under controlled conditions. The resulting fuel is classified as a carbonaceous slurry because, at room temperature, its main combustible components (coal, charcoal, algal materials, and residual fuel oil) are solid, i.e., it does not conform to the shape of a container.

[0080] While not wishing to limit the scope of the present invention, the inventors believe that the following problems and acceptable findings in prior alternative fuel technologies have been overcome by formulations of fuels according to specific embodiments of the relevant embodiments / aspects of the present invention. These notes should be understood to be relating to specific embodiments of the present invention and not covering all aspects of the broadest form of the invention. Therefore, the following should not be construed as applying to all embodiments of the present invention generally covered in the appended claims:

[0081] 1. Previous attempts to use coal-oil / diesel mixtures in diesel engines (e.g., performance tests of low-speed two-stroke diesel engines using coal-based fuel by Sulzer / Thermoelectron (1978-82), CSIRO (1987), JB Dunlay, JP Davis, Thermo Electron Corporation, HA Steiger, MK Eberle, and Sulzer Brothers, conducted under contract No. EF-77-C-01-2647) all resulted in insufficient atomization and combustion performance due to coal agglomeration. Therefore, recent attempts to use carbonaceous slurry in diesel engines are limited to single-component carbonaceous water slurries (e.g., coal A-water, coal B-water, charcoal A-water).

[0082] 2. While black coal (essentially hydrophobic) produces slurries with high specific energy, and lower-grade lignite and charcoal (essentially hydrophilic) produce highly stable slurries, although they have extremely low specific energy (for example, requiring more than three times the amount of fuel injection), making them difficult to use, no attempts have been made to combine these different solids to improve both the overall specific energy and stability and produce usable fuel.

[0083] 3. Although coal produces slurry fuel with a high specific energy, it is known to emit more CO2 than biomass-based fuels, and no attempts have been made to produce blended carbonaceous slurry fuel for diesel engines.

[0084] 4. Ammonia, more specifically anhydrous ammonia (ammonia without water), is known to be a substitute for petroleum as a transport fuel in diesel engines modified to overcome significant flammability issues. Furthermore, when generated from renewable energy, ammonia-modified engines exhibit extremely low CO2 intensity. However, the inventors have unexpectedly discovered that in embodiments of the present invention, ammonia can be blended with aqueous coal-based or charcoal-based slurry fuels to both reduce CO2 and SOx intensity and improve the flammability of ammonia. This is advantageous because using aqueous blended ammonia fuels eliminates or reduces the need for pressurized storage of ammonia, thus providing other overall benefits in fuel storage that would otherwise be limited to ammonia alone.

[0085] 5. In addition, the inventors unexpectedly discovered that the addition of ammonia to the slurry improved overall combustion in terms of reducing ignition delay and the time taken for combustion, as measured from accurate measurements of cylinder pressure and crankshaft rotation. In experimental runs, the inventors found that the ignition delay was reduced by more than 25%, and that the engine could operate at an air inlet temperature of 95°C, which is lower than 150°C for a coal-only slurry. The inventors hypothesize that this improvement in combustion is due to the explosive evaporation of ammonia within the slurry droplets formed by atomization, thereby improving the atomization properties that are effective for a given fuel viscosity and injection conditions. This allowed for a reduction in injection pressure, and the lower injection velocity also reduced atomizer wear. The improvement in combustion was unexpected because ammonia evaporation is highly endothermic, which delays ignition and makes the combustion rate of ammonia in the engine much slower than that of other gaseous fuels (e.g., natural gas). Contrary to expectations, it was found that these adverse effects were substantially offset by the positive effects on atomization. The slow-burning properties of ammonia were significantly increased by the overlapping ignition points in the charcoal burning process, which is presumed to have reduced unburned ammonia in the engine exhaust gas by more than 75% (measured by mass spectrometry) according to a given overall combustion stoichiometry.

[0086] Considering the above, the fuels of the present invention provide several advantageous formulations with various improved fuel properties that can be optimized for end-use.

[0087] It should be recognized that the present invention is suitable for use in compression-ignition or direct-injection combustion chambers of diesel engines. Accordingly, certain engines may include conventional compression-ignition or diesel engines, or improved, modified, or otherwise derived from conventional compression-ignition or diesel engines that operate using a fuel containing carbonaceous particles suspended in an aqueous medium. In certain embodiments, the carbonaceous aqueous slurry fuel according to the present invention can be used to replace heavy fuel oil in diesel engines, for example, in stationary power generation systems larger than 5 MW, and in large vessels.

[0088] For ocean-going vessels, the use of carbonaceous slurry fuel is advantageous because it can address the sulfur emission restrictions for ocean-going vessels, which are imposed by many administrative jurisdictions that restrict the use of fuel oil on board. The sulfur content is as low as 0.5%, and in some cases, it currently exceeds 0.10%. The sulfur content of carbonaceous slurry fuel can be adjusted to meet these specific sulfur content restrictions.

[0089] Ammonia: Embodiment of the present invention in the case of coal blend fuels: This fuel mixture has the mutual benefits of these difficult-to-ignite fuels and the benefits of CO2. For example:

[0090] When ammonia is produced using renewable energy, the resulting slurry fuel has a lower CO2 intensity. Compared to a fuel containing only coal slurry, the CO2 emission intensity is approximately 94 kg CO2 / GJ (higher heating value). When 30 wt% green ammonia is added and replaces 30 wt% coal, the slurry CO2 intensity decreases by approximately 25% to 70 kg CO2 / GJ, depending on the heating value of the coal in the slurry.

[0091] Another benefit of ammonia is its effect on coal ignition delay. The coal-water slurry of the above rheology typically exhibits an ignition delay of 7 to 12 ms. A slurry containing 50 wt% coal, 15 wt% ammonia, and 35 wt% water under the same injection conditions typically exhibits an ignition delay of 3 to 5 ms. This shorter ignition delay allows for engine operation at higher engine speeds and higher fuel supply rates without placing a mechanical load on the engine. The shorter ignition delay is due to increased atomization because ammonia's vapor pressure is much higher than that of water, causing ammonia from the slurry droplets, which are sprayed while heated once inside the combustion charge in the engine, to ignite.

[0092] Using the latter formulation, the fuel can also be stored at atmospheric pressure at 20°C. At higher ammonia ratios, pressurized fuel storage is required, depending on the vapor pressure of the slurry.

[0093] The overall addition of ammonia to the fuel formulation of the present invention replaces the use of coal (by energy standards) by reducing the CO2 intensity of the fuel and improving ignition of the coal component through improved atomization.

[0094] The use of coal and ammonia allows for direct injection of ammonia without the need for ignition-enhancing measures, as the coal ignition ensures the ignition and rapid combustion of the ammonia. In comparison, using 100% ammonia with a similar injection system results in insufficient ammonia ignition and extremely slow combustion, potentially causing the engine to become inoperable due to unburned ammonia in the exhaust.

[0095] Embodiments of the present invention (slurry) in the case of charcoal: coal blend fuel:

[0096] • When charcoal is produced from intentionally cultivated woody biomass, this blend results in a CO2 intensity that is roughly proportional to the amount of coal replaced. For example, a 50:50 charcoal:coal ratio has a CO2 intensity of approximately 55 kg / GJ (HHV basis) compared to 94 kg / GJ (HHV basis) for coal-only slurry. The overall CO2 benefit is greater when charcoal is produced from waste that is typically consumed in incineration or wildfires. Specific values ​​(e.g., kg CO2 / MWh electricity) require a detailed lifecycle analysis of specific energy systems, as this also needs to identify what charcoal-coal slurry fuel will replace (e.g., coal-fired power plants, natural gas-fired power plants, diesel backup power plants, etc.).

[0097] This blend allows wear tests to show that charcoal combustion residue (ash) does not increase cylinder wear, i.e., it produces the same wear as with clean lubricating oil, thus providing benefits in terms of CO2 reduction and cylinder wear reduction, roughly proportional to the amount of coal replaced. On the other hand, coal increases cylinder wear by 100 to 1000 times compared to clean oil, depending on the proportion of mineral-derived ash.

[0098] Considering the above, the fuels of the present invention provide several advantageous formulations with various improved fuel properties that can be optimized for end-use. [Examples]

[0099] (Example 1) Fuel Blend Characteristics Several advantageous formulations were found to possess various improved fuel properties that could be optimized for their end-use.

[0100] Table 1 below shows a nominal ranking of key attributes for different carbonaceous fuels (5 = best, and 1 = worst). This ranking indicates how well blends could produce fuel of optimal quality for a particular application, provided the mixture is suitable. Note that none of the following fuels have been used in combination, nor have their use been proposed, due to their significantly different properties and the inadequate results reported from coal-oil, coal-diesel, coal-ethanol, and coal-methanol mixtures.

[0101] [Table 1]

[0102] (Example 2) Fuel blend examples (Example 2.1) charcoal-water mixture A slurry fuel containing 50 wt% charcoal was formed by generating woody material (material supplied from trees, not bark, leaves, or twigs), carbonizing it at 350°C, grinding it to -90 μm, and blending it with water using a small amount of dispersant (0.1 wt% sodium polystyrene sulfonate). The viscosity of the slurry was measured using a Kinexus rheometer. The resulting slurry was found to have excellent rheological properties, with a viscosity of 24,000 mPa.s at 0.1 / s and 300 mPa.s at 3,000 / s. However, the fuel was found to be biologically unstable, with dense white colonies forming on the fuel surface within 48 hours at 21°C. These dense white colonies were unidentified molds that typically form within a few days of processing biomass products, such as roasted wood and low-temperature charcoal. We found that adding a small amount of condensable pyrolysis products (3 wt% of the total slurry) collected during carbonization completely prevented microbial activity on the fuel, and it remained stable at 21°C for over 200 days. The condensable pyrolysis products contained wood vinegar and a cocktail of liquid hydrocarbons at room temperature (e.g., creosote, phenol, tar, all of which have significant fuel value). When carbonized at 350°C, these can account for up to 50% of the energy content of the original biomass.

[0103] (Example 2.2) Charcoal-ammonia-water mixture In this case, the slurry fuel was formulated using 50 wt% charcoal produced at 350°C, blended with an aqueous ammonia solution containing 20 wt% ammonia and 80 wt% water. The viscosity of the slurry was measured using a Kinexus rheometer.

[0104] The resulting slurry was found to have excellent rheological properties, with a viscosity of 20,000 to 40,000 MPa.s at 0.1 / s and 200 to 350 MPa.s at 3,000 / s. Importantly, the absence of microbial activity was consistent with the comparative examples.

[0105] (Example 2.3) Charcoal-ammonia aqueous solution mixture The slurry fuel was formulated using 5 wt% charcoal produced at 350°C, blended with an aqueous ammonia solution containing 20 wt% ammonia and 80 wt% water. This charcoal-ammonia-water slurry fuel was used as fuel in a 4-liter single-cylinder diesel laboratory engine (a single-cylinder engine modified from a Satyajeet SL22). The charcoal-ammonia-water slurry fuel was injected into the engine using a modified stock jerk pump and a standard fuel injection pump (not illustrated).

[0106] Engine tests revealed that this small amount of charcoal (5 wt%) significantly improved the combustion characteristics of (anhydrous) ammonia. When liquid ammonia is injected directly into a diesel engine, it ignites very poorly or not at all without a diesel pilot injection to provide an ignition source. The small amount of charcoal (5 wt%) was found to eliminate the need for another pilot injection of diesel fuel and result in a reduction of CO2 emissions equivalent to the amount of diesel not used (approximately 78 kg CO2 / GJ in diesel equivalent).

[0107] (Example 2.4) Biomass charcoal and bituminous coal mixture The slurry fuel was formulated using 25 wt% biomass charcoal produced at 350°C, blended with 25 wt% bituminous coal in water. The viscosity of the slurry was measured using a Kinexus rheometer. A typical analysis (on an anhydrous, ash-free basis) of the charcoal produced from Pinus radiata used in this experiment is as follows: Carbon: 72 wt% Hydrogen: 5.4 wt% Nitrogen: 0.08 wt% Sulfur (total): 0.05 wt% Oxygen (difference): 22.5 wt%

[0108] The resulting slurry was found to have excellent rheological properties, with a viscosity of 20,000 to 40,000 MPa.s at 0.1 / s and 250 to 350 MPa.s at 3000 / s.

[0109] This slurry fuel was used as fuel in a fully instrumented 3.9-liter single-cylinder diesel experimental engine (a single-cylinder engine modified from a Satyajeet SL22). The slurry fuel was injected into the engine using a modified stock jerk pump with a media separating diaphragm up to 250 bar, or using an electronically controlled hydraulic fuel pump at pressures of 350 to 500 bar (not illustrated). The experiment involved preheating the engine coolant to 95°C using an external gas combustion heater, followed by starting with the slurry fuel. The engine was equipped with a Roots blower and electrically heated to allow for a wide range of operating conditions to be simulated. To allow for reasonable comparison with diesel operation, the inlet air pressure was adjusted to maintain a constant overall combustion stoichiometry (7 vol% O2 at full load). Torque performance and unburned fuel components were investigated at engine speeds from 200 to 800 rpm, within the range in which the engine was well-operated.

[0110] Engine tests revealed that blending biomass charcoal and bituminous coal yielded several advantages, including reduced wear. This wear reduction was slightly higher than that of bituminous coal due to the anti-scuff properties of the ash produced from charcoal. It also showed increased spheroidization of siliceous ash from coal due to alkali-ash reactions (ash from charcoal is rich in Na, Ca, and Mg, and its oxides react with siliceous coal ash to form low-melting-point phases, such as a mixture of xNa2O, xCaO, and xSiO2). The use of charcoal also reduced CO2 emissions in roughly proportion to the amount of coal replaced (approximately 94 kg CO2 / GJ, coal equivalent).

[0111] (Example 2.5) Ammonia and coal / charcoal mixtures A successful formulation of an ammonia:coal slurry blend was achieved by adding water to a coal filtration cake containing 35 wt% water in a low-shear mixing tank to form a basic slurry with approximately 50 wt% coal. This coal had a volatile matter content of 33 wt% on a dry basis and an ash content of 2.1 wt% on a dry basis. The mass-average size was 12 μm, and the D95 was 90 μm. Approximately 0.1 wt% of poly(sodium 4-styrene sulfonate) surfactant was added to ensure shea-thinning rheology. The composition of the mixture was then adjusted to obtain the required ratio of ammonia:water:coal by individual direct addition to the slurry in a blender. In the case of ammonia, this was done by sparging it directly into the slurry during stirring. However, in other cases where a lower ratio of ammonia was required, ammonia was prepared as an ammonia:aqueous solution prepared by sparging anhydrous ammonia gas directly into water. Sparging causes the rapid incorporation of ammonia, as ammonium ions, into the solution. The objective was to enable injection by adding as much ammonia or coal as possible while maintaining shear-thinning rheology at an apparent viscosity of typically 100-300 mPa·s. The ammonia:coal slurry was then fueled into a 3.9-liter single-cylinder low-to-medium speed (200-800 rpm) experimental engine (a single-cylinder engine modified from a Satyajeet SL22) or into a high-pressure spray combustion chamber for combustion testing. The spray chamber was designed by CSIRO for these experiments, had an internal volume of 9 liters, and used optical access for high-speed photography via a sapphire window. The maximum operating pressure was limited to 200 bar.

[0112] Overall, it was found that a low ammonia concentration of 5 wt% in the slurry resulted in smoother and more complete combustion than (than). In detail, the rate of heat release in the engine progressed smoothly without any premixed combustion spikes. CO and NOx levels were also at least 25% lower than with diesel fuel at the same engine rpm and load, and the engine was able to produce its maximum rated torque at all speeds from 200 to 800 rpm. Engine performance was also better than with coal-only slurry, and the ammonia blend fuel required only an air inlet temperature of 90°C to achieve combustion equivalent to the 150°C air inlet temperature with coal slurry. Engine performance with the blend was far better than with ammonia-only (as liquid anhydrous ammonia) injection, and direct injection of ammonia-only failed to achieve ignition. It is noteworthy that the combustion stoichiometry was maintained at a constant 7 vol% O2 in the exhaust by varying the inlet pressure, and was maintained at a constant level with different preheating.

[0113] In experiments using a high-pressure spray chamber, the ignition delay with 5 wt% ammonia was approximately 3 to 5 ms shorter than with coal slurry, and the jet angle was 2 to 3° wider, both demonstrating the overall benefits of ammonia in slurry. Injection start conditions were 80 bar and 575°C, and injection was performed at a constant pressure of approximately 400 bar via a 0.4 mm single-orifice injector. Higher ammonia ratios (equivalent to 30 wt% ammonia:70 wt% aqueous solution) resulted in lower fuel viscosity, enabling lower injection pressures and similar injection velocities. The mutual benefits of the ammonia:coal slurry blend were clearly demonstrated.

[0114] The benefits of ammonia in improving carbonaceous slurry combustion through explosive atomization are greater with lower calorific value carbon materials, such as biomass charcoal, and generally with heat-treated lignite / lignite, which produce lower quality slurries in terms of calorific value per given viscosity, due to the higher vapor pressure of ammonia compared to water. The addition of ammonia improves atomization so that slurries with a high solids content, and therefore higher viscosity, can atomize sufficiently to enable short ignition delay and efficient combustion.

[0115] (Example 3) Ammonia and coal slurry fuels A slurry containing 55 wt% Hunter Valley bituminous coal (with less than 3% ash content) and 45 wt% ammonia-aqueous solution was successfully injected into a 3.9-liter single-cylinder test engine. As described in previous examples, this test engine was a fully instrumented single-cylinder diesel experimental engine modified from a single-cylinder engine, Satyajeet SL22. The slurry fuel was injected into the engine using a modified stock jerk pump with a medium separation diaphragm up to 250 bar, or using an electronically controlled hydraulic fuel pump at pressures of 350 to 500 bar (not illustrated). The ammonia-aqueous solution contained 25 wt% ammonia and 75 wt% water, and was prepared by slowly fizzing anhydrous ammonia in a coal-water slurry at 22°C.

[0116] The engine was capable of generating its rated torque over an operating speed range of 300 to 750 rpm. Engine performance was monitored using precise measurements of cylinder pressure and crank position, along with exhaust gas analysis. The cylinder heat dissipation rate was smooth and free from pressure spikes from premixed combustion. Exhaust gas analysis showed complete combustion, with CO and NOx significantly reduced compared to diesel or coal-water slurry fuel feeds.

[0117] Experiments in a high-pressure spray combustion chamber (85 bar, 570°C, 400 μm single orifice nozzle at the start of injection) showed that the fuel jet angle was approximately 5° wider with coal-water slurry, and that combustion occurred significantly closer to the injector nozzle.

[0118] Overall, the addition of ammonia to the aqueous phase improved the fuel rheology, as evidenced by the reduction in injection time (using a constant-pressure hydraulic intensifier-type injector).

[0119] Those skilled in the art will recognize that the present invention as described herein is open to modifications and alterations other than those specifically described. It will be understood that the present invention includes all such modifications and alterations that are in the spirit and scope of the invention.

[0120] Where the terms “comprise,” “comprises,” “comprised,” or “comprising” are used herein (including in the claims), they should be interpreted as identifying the presence of the described feature, integer, process, or component, but not as excluding the presence of one or more other features, integers, processes, components, or groups thereof.

Claims

1. A mixture of 25 to 70 wt% finely ground carbonaceous particles, 5 to 40 wt% ammonia, and Residue containing aqueous solvent A direct injection, compression ignition, or diesel engine fuel, including Carbonaceous particles originate from coal-based materials, biomass, charcoal, or mixtures thereof. fuel.

2. The fuel according to claim 1, wherein the aqueous solvent contains water.

3. The fuel according to claim 1 or 2, wherein the mass fraction of carbonaceous particles in the fuel is in the range of 40 to 70 wt%, preferably 45 to 70 wt%, of the fuel.

4. The fuel according to any one of claims 1 to 3, wherein the carbonaceous particles derived from biomass include carbonaceous by-products from incomplete biomass gasification, pyrolysis, or low-temperature carbonization and roasting.

5. The fuel according to any one of claims 1 to 4, wherein the carbonaceous particles are derived from at least one coal-based material.

6. Carbonaceous particles, The residue contains 2 to 70 wt% of carbonaceous particles derived from biomass or charcoal, and carbonaceous particles derived from at least one coal-based material. A fuel according to any one of claims 1 to 4, comprising a mixture containing the following.

7. The fuel according to any one of claims 1 to 6, wherein carbonaceous particles derived from at least one coal-based material are selected from anthracite, bituminous coal, or lignite or igneous coal.

8. A direct injection, compression ignition, or diesel engine fuel containing carbonaceous particles suspended in an aqueous solvent, 40 to 70 wt% carbonaceous particles, containing 2 to 100 wt% carbonaceous particles derived from biomass or charcoal. Residue containing aqueous solvent Fuel, including

9. The fuel according to claim 6, further comprising 5 to 40 wt% ammonia, preferably 10 to 30 wt% ammonia, more preferably 20 to 40 wt% ammonia.

10. The fuel according to claim 8 or 9, wherein the mass fraction of carbonaceous particles in the fuel is 45 to 70 wt%.

11. The fuel according to any one of claims 8 to 10, wherein the carbonaceous particles derived from biomass include carbonaceous by-products from incomplete biomass gasification, pyrolysis, or low-temperature carbonization and roasting.

12. The fuel according to any one of claims 8 to 11, wherein the remainder of the carbonaceous particles preferably comes from at least one coal-based material selected from anthracite, bituminous coal, or lignite or igneous coal.

13. The fuel according to any one of claims 8 to 12, wherein the aqueous solvent contains water.

14. The fuel according to any one of claims 1 to 13, wherein the carbonaceous particles have a mass-average particle size of less than 20 μm, preferably about 10 μm to about 20 μm.

15. The fuel according to any one of claims 1 to 14, wherein the carbonaceous particles have a d95 that is about 3 to about 10 times larger than the mass-average diameter.

16. The fuel according to any one of claims 1 to 15, wherein d95 is about 4 to about 5 times larger than the mass-average diameter.

17. The fuel according to any one of claims 1 to 16, further comprising at least one additive that controls at least one of the properties of rheology, ignition, combustion and NOx formation, or ash.

18. The fuel according to claim 17, wherein at least one additive comprises a solution of a condensate by-product from the thermal decomposition and carbonization of biomass, preferably wood vinegar.

19. Preferably, the fuel according to any one of claims 1 to 18 further comprises a dispersant selected from the group consisting of polystyrene sulfonate, polyisoprene sulfonate, carboxymethylcellulose, humic acid, polyacrylate, and sodium salts of copolymers of acrylic acid and other acrylic monomers; lignosulfonate, naphthalene sulfonate, or sodium or ammonium salts of naphthalene sulfonate formaldehyde condensate; cellulose ethers containing hydroxyethylcellulose or hydroxypropylcellulose; polysaccharides containing dextrin; polyoxyethylene sorbitan monooleate; rosin or saponin-based dispersants; or polycarboxylate.

20. The fuel according to any one of claims 1 to 19, wherein the viscosity of the fuel is generally the shearing viscosity.

21. A fuel according to any one of claims 1 to 20, having an apparent viscosity of less than 500 mPa.s at 100 / s and greater than 20,000 mPa.s at 0.1 / s (measured using a Kinexus rheometer).

22. The fuel according to claim 21, wherein the fuel is generally a shearing of up to 100,000 / s.

23. Use of the fuel according to any one of claims 1 to 22 in compression ignition or in the combustion chamber of a diesel engine.

24. The use of the diesel engine according to claim 23, wherein the diesel engine includes power generation, marine, or locomotive engines.

25. A method for preparing fuel for direct injection, compression ignition, or for directing fuel to the combustion chamber of a diesel engine, The process involves mixing carbonaceous particles and water to form a fuel mixture of carbonaceous particles suspended in water, wherein the carbonaceous particles are derived from coal-based materials, biomass, charcoal, or mixtures thereof. The process of adding ammonia to the fuel mixture, This process produces a fuel mixture containing a mixture of 25 to 70 wt% finely ground carbonaceous particles, 5 to 40 wt% ammonia, and a residue containing water. Methods that include...

26. Ammonia, Storage of fuel mixtures, or The mixing region between the fuel storage container and the fuel injection in the engine injector. The method according to claim 25, which is added to the fuel mixture during at least one of the following:

27. The method according to claim 25 or 26, wherein the carbonaceous particles comprise a mixture containing 2 to 70 wt% of carbonaceous particles derived from biomass or charcoal, and a remainder comprising carbonaceous particles derived from at least one coal-based material.

28. A method for preparing fuel for direct injection, compression ignition, or for directing fuel to the combustion chamber of a diesel engine, The process includes blending carbonaceous particles and water to form a fuel mixture of carbonaceous particles suspended in water, The mass fraction of carbonaceous particles in the fuel mixture is 2 to 1000 wt% of carbonaceous particles derived from biomass or charcoal From which 40 to 70 wt% are selected, method.

29. The method according to claim 28, wherein the carbonaceous particles in the fuel mixture comprise at least two different types of carbonaceous particles blended together, selected from 2 to 70 wt% of carbonaceous particles derived from biomass or charcoal, and a residue comprising coal-based particles.

30. The method according to claim 29, wherein different carbonaceous particles are blended in the engine immediately before use.

31. The method according to claim 29 or 30, wherein a blending step is performed to obtain a homogeneously mixed slurry fuel.

32. The method according to any one of claims 28 to 31, further comprising the step of adding 5 to 40 wt% ammonia to a fuel mixture.

33. The method according to any one of claims 26 to 32, wherein the fuel mixture comprises the fuel according to any one of claims 1 to 22.

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