Boron-based nanofluid fuel with dual-function catalytic combustion and method of implementing the same

Abstract

A boron-based nanofluid fuel with bifunctional catalytic combustion and its realization method are disclosed. The fuel consists of RP-3 kerosene as the base fuel, boron-coated polyphosphononitrile carbon (CPZS@B) as a nanoparticle additive, and Span 80 as a surfactant. This invention starts from the nanostructure of the inorganic heteroatom carbon-based coating B, realizing a synthesis strategy for heteroatom carbon-based coated B particles. This enables the formation of a heteroatom-based inorganic coating layer (CPZS@B) for bifunctional catalysis of B oxidation and hydrocarbon fuel combustion, providing a solution for improving fuel energy density and reducing fuel consumption in supersonic aircraft under extreme operating conditions.

Description

Technical Field

[0001] This invention relates to a technology in the field of aviation fuel, specifically a boron-based nanofluid fuel with dual-function catalytic combustion and its implementation method. Background Technology

[0002] Hypersonic aircraft face high drag (Ma = 0.9) during transonic flight, hindering the breaking of the sound barrier. To achieve greater thrust, fuel consumption increases dramatically, severely impacting flight range. Therefore, improving fuel energy density to reduce fuel consumption under extreme operating conditions is a pressing engineering challenge. Nanofluid fuel refers to a uniform and stable suspension prepared by dispersing high-energy nanoparticles into traditional fuels. Adding nanoparticles to traditional liquid fuels not only improves the volumetric energy density and combustion rate but also utilizes nanoparticles as catalysts to reduce emissions of particulate matter and nitrogen oxides. Therefore, nanofluid fuel holds promise as a next-generation fuel, achieving energy conservation, emission reduction, and increased flight range. Boron, with a volumetric energy density of 136.38 kJ / cm³, is a valuable addition to these fuels. 3The highest efficiency of boron is 3.09 times that of magnesium and 1.66 times that of aluminum. It is currently the most promising nano-additive for realizing high-energy nanofluid fuels. In addition, the combustion products of boron are clean and environmentally friendly. However, due to the high melting and boiling points of boron, as well as the high boiling point of the oxide film B2O3 formed on the surface, boron suffers from poor ignition performance and difficulty in complete combustion. There are generally two methods to improve boron combustion: one is to mix boron with other metals or metal oxides, and the other is to coat modified boron to promote its combustion. For metals, magnesium, aluminum, iron and other elemental metal particles (such as Ni and Mo) are often mixed with boron particles to improve the combustion characteristics of boron. By mixing metals, the temperature around the boron particles can be increased, the ignition temperature of boron can be reduced, and the ignition and combustion of boron particles can be promoted. However, during the combustion process, all of these additives participate in the ignition and combustion process. And the melting point of the metal oxide produced by the combustion of metals is higher than that of boron oxide. Although the initial oxidation temperature of boron is reduced, the dense metal oxide layer produced by the combustion of metals actually prevents the oxidation of boron. Metal oxides primarily act as catalysts (such as rare earth oxide catalysts) or solid oxygen carriers (such as CeO2, CuO, Bi2O3, and Fe2O3) in the combustion of boron fuel. The addition of these metal oxides reduces the energy density of boron, and the amount added is usually substantial. Coating boron is the best method to improve its ignition and combustion performance. A drawback of coating with metals such as Mg and Fe is that the metals are easily oxidized in air, which affects the combustion performance of boron nanoparticles. High-energy materials such as AP and NaN3 can release a large amount of heat during combustion, increasing the surface temperature of the boron powder and thus promoting the ignition and combustion of boron particles. However, these methods still cannot eliminate the oxide layer on the surface of boron, which still inhibits its oxidation. Materials such as LiF can remove oxides from the surface of boron particles through chemical reactions, improving their ignition and combustion performance. However, they are usually fluorinated materials, producing toxic substances after combustion. Although surface coating of boron particles is a good method to improve their ignition and combustion performance, practical studies have found that it is difficult to achieve a completely uniform coating on the surface of boron particles. The role of coating materials in kerosene-based nanofluid fuels should be considered comprehensively, taking into account their respective promoting effects on boron (B) and kerosene. The coating material should not only improve the combustion performance of kerosene but also achieve a uniform coating of B particles to promote boron oxidation. Furthermore, the introduction of the coating material should avoid reducing the calorific value of B and should also prevent the formation of a dense shell and porous residues on the surface of combustion products, thus promoting further boron oxidation. Summary of the Invention

[0003] This invention addresses the problems of existing coatings inhibiting the complete oxidation of boron and reducing its calorific value. It proposes a boron-based nanofluid fuel with dual-function catalytic combustion and its realization method. Starting from the nanostructure of inorganic heteroatom carbon-based coatings of boron, a synthesis strategy for heteroatom carbon-based coated boron particles is realized, which can form a heteroatom-based inorganic coating (CPZS@B) for dual-function catalysis of boron oxidation and hydrocarbon fuel combustion. This provides a solution for improving fuel energy density and reducing fuel consumption in supersonic aircraft under extreme operating conditions.

[0004] This invention is achieved through the following technical solution:

[0005] This invention relates to a boron-based nanofluid fuel with dual-function catalytic combustion, comprising RP-3 kerosene as the base fuel, boron-coated polyphosphononitrile carbonized (CPZS@B) as a nanoparticle additive, and Span80 as a surfactant.

[0006] The mass ratio of the carbonized polyphosphononitrile-coated boron (CPZS@B) to the base fuel is 5-25%, and the mass ratio of Span 80 to the base fuel is 2%.

[0007] This invention relates to a method for realizing the above-mentioned boron-based nanofluid fuel, which is obtained by uniformly dispersing the base fuel, Span 80 and boron nanoparticles coated with polyphosphononitrile carbon (CPZS@B) in an ultrasonic environment in proportion.

[0008] The aforementioned carbonized polyphosphononitrile-coated boron nanoparticles are prepared by the following method:

[0009] Step 1: Disperse boron powder in acetonitrile solvent and add triethylamine;

[0010] Step 2: Further add hexachlorocyclotriphosphazene and 4,4′-dihydroxydiphenyl sulfone, and carry out polycondensation reaction under ultrasonic heating;

[0011] The ultrasonic heating refers to a condensation reaction in water at an ultrasonic power of 100W and a temperature of 50°C for 5 hours.

[0012] The polycondensation reaction is preferably carried out after the reaction is completed, by washing the reaction product three times each with ethanol and water, and then freeze-drying it at -60°C for 72 hours to obtain a gray solid product, polyphosphazene.

[0013] Step 3: After encapsulating B nanospheres with the polyphosphazene product obtained in Step 2, carbonize the product to obtain carbonized polyphosphazene-encapsulated B nanospheres (CPZS@B).

[0014] The carbonization process refers to: raising the temperature from room temperature to 500℃ at a rate of 5℃ / min under a high-purity nitrogen atmosphere and maintaining the temperature for 5 hours, then raising or maintaining the temperature to the target temperature of 700℃ at a rate of 5℃ / min and maintaining the temperature for 2 hours.

[0015] The high-purity nitrogen atmosphere refers to a nitrogen flow rate of 100 mL / min, with vacuuming and nitrogen purging performed three times each.

[0016] The carbonization temperature of the carbonized polyphosphononitrile (CPZS) is 700℃.

[0017] Technical effect

[0018] This invention employs a self-assembled boron-coated particle method, starting from the nanostructure of an inorganic heteroatom carbon-based coating B, to synthesize a novel heteroatom carbon-based coated B particle. This forms a heteroatom-based inorganic coating layer, achieving a dual-functional catalytic effect on B oxidation and hydrocarbon fuel combustion. The fuel exhibits advantages such as stable physical morphology, no stratification, and good dispersion stability at room temperature. The preparation process, based on the formation of a heteroatom-based inorganic coating layer for dual-functional catalysis of B oxidation and hydrocarbon fuel combustion, is simple to operate and highly practical. The resulting inorganic heteroatom-coated boron nanospheres exhibit an increased initial oxidation temperature of 148.4℃, and the formed nanofluid fuel shows an 85ms improvement compared to boron-containing kerosene nanofluid fuel, while also enhancing the fuel's oxidation, ignition, and combustion performance. The prepared nanofluid fuel possesses advantages such as stable physical morphology, no stratification, and good dispersion stability at room temperature, and the preparation process is simple to operate and highly practical. Attached Figure Description

[0019] Figure 1 Scanning electron microscope (SEM) images of PZS@B-1.0 (a) and CPZS@B-1.0 (b), and transmission electron microscope (TEM) image of CPZS@B-1.0 (C, N, S, O, P and B) (c);

[0020] Figure 2 TG-DSC plots for B and CPZS@B-0.1, 0.5 and 1.0;

[0021] Figure 3 A schematic diagram showing the ignition delay time of RP-3 and RP-3 containing different amounts of nanoparticles under pulse ignition conditions;

[0022] Figure 4 Ignition dynamic process diagrams for RP-3, B / RP-3 and CPZS@B-1.0 / RP-3. Detailed Implementation

[0023] Example 1

[0024] In this embodiment, polyphosphazene-coated B nanospheres (PZS@B) were synthesized and PZS@B was carbonized according to the following steps:

[0025] Step 1: Add 80 mL of acetonitrile solvent to the two-necked flask;

[0026] Step 2: Add boron powder (X g, where X = 0.1, 0.5, and 1.0 times the total mass of HCCP and BPS) to a two-necked flask and disperse it in acetonitrile solvent by ultrasonication (20℃, 100W, 30min);

[0027] Step 3: Add hexachlorocyclotriphosphazene (0.4 g) and 4,4′-dihydroxydiphenyl sulfone (0.8 g) to the two-necked flask and dissolve them in acetonitrile;

[0028] Step 4: Add 4 mL of triethylamine to the two-necked flask;

[0029] Step 5: Place the two flasks in water with an ultrasonic power of 100W and a temperature of 50°C for a condensation reaction for 5 hours.

[0030] Step 6: After the reaction is complete, wash the sample three times each with ethanol and water.

[0031] Step 7: Freeze-dry at -60℃ for 72 hours to obtain a gray solid product, polyphosphazene;

[0032] Step 8: Take 1.0g of polyphosphazene-encapsulated B nanospheres and place them in a ceramic boat;

[0033] Step 9: Place the porcelain boat into a tube furnace, where the carbonization atmosphere is high-purity nitrogen gas at a flow rate of 100 mL / min;

[0034] Step 10: Evacuate and purge the tubular furnace with nitrogen three times each;

[0035] Step 11: Increase the temperature from room temperature to 500℃ at a rate of 5℃ / min and maintain the temperature for 5 hours;

[0036] Step 12: Maintain or raise the temperature to the target temperature of 700℃ at a rate of 5℃ / min, and maintain this temperature for 2 hours.

[0037] Step 13: When the temperature drops to room temperature, carbonized polyphosphononitrile-encapsulated B nanospheres (CPZS@B) are obtained, namely CPZS@BX, where X represents multiples of 0.1, 0.5 and 1.0 of the total mass of HCCP and BPS, namely CPZS@B-0.1, CPZS@B-0.5 and CPZS@B-1.0 respectively.

[0038] like Figure 1 and 2As shown, boron-coated synthetic polyphosphononitrile was carbonized; the resulting carbonized boron-coated polyphosphononitrile consisted of spherical nanoparticles with a diameter of approximately 500-800 nm, and C, N, S, O, and P elements were uniformly distributed on the nanoparticles. Except for CPZS@B-0.1, the other three samples (B, CPZS@B-0.5, and CPZS@B-1.0) all showed weight gain after oxidation. The weight gain of B reached 217.9%. The mass gains of CPZS@B-0.5 and CPZS@B-1.0 were 145.9% and 171.2% of their original mass, respectively. CPZS@B-0.1, however, only gained 64.4% of its original mass. The weight loss of CPZS@B-0.1 was attributed to the insufficient amount of B. i The initial oxidation temperature was determined by the tangent method. The oxidation properties of reaction B are shown in Table 1.

[0039] Table 1

[0040]

[0041] CPZS-encapsulated B nanoparticles T i The T values ​​of B, CPZS@B-0.5, and CPZS@B-1.0 were decreased. i The oxidation temperatures were 791.1, 645.1, and 641.7 °C, respectively, indicating that the oxidation temperature of B nanoparticles coated with carbonized polyphosphononitrile was advanced. Furthermore, analysis of the heat release rates of the four nanoparticles revealed that the heat release of the CPZS-coated B nanoparticles reached 21.28 kJ / g (compared to 21.33 kJ / g for pure B), representing 99.8% of the heat release of pure B. However, at this point, B accounted for only 59.6% of the mass of CPZS@B-1.0. This indicates that CPZS contributed to the heat release during oxidation, and also shows that the heat release rate of the 59.6% B nanoparticles was significantly higher than that of pure B.

[0042] Example 2

[0043] This embodiment tests the base fuel as follows:

[0044] Step 1: Add kerosene to the beaker; label it RP-3.

[0045] This embodiment uses a suspended droplet pulse ignition experimental device and a high-speed camera to measure the ignition and combustion characteristics of RP-3. The ignition and combustion of RP-3-containing fuel mixtures are listed.

[0046] like Figure 3 and Figure 4 As shown, in this embodiment, the RP-3 fuel ignition delay time is 402ms; the combustion duration is 3880ms.

[0047] Example 3

[0048] In this embodiment, the nanofluid fuel is configured in the following proportions:

[0049] Step 1: Add 1g of RP-3 to the beaker;

[0050] Step 2: Add B to the beaker, with a mass percentage of 5-25%;

[0051] Step 3: Add Span 80 to the beaker at a mass percentage of 2%.

[0052] Step 4: Disperse the nanofluid fuel uniformly by ultrasonic dispersion for 10 minutes (100W, 20℃).

[0053] This embodiment uses a suspended droplet pulse ignition experimental device and a high-speed camera to measure the ignition and combustion characteristics of 5-25% B / RP-3 nanofluid fuels. Ignition and combustion results with 20% B / RP-3 are also provided.

[0054] like Figure 3 and 4 As shown, in this embodiment, the RP-3 with 20% B added has an ignition delay time of 478ms and a combustion duration of 3170ms.

[0055] Example 4

[0056] In this embodiment, the nanofluid fuel is configured in the following proportions:

[0057] Step 1: Add 1g of RP-3 to the beaker;

[0058] Step 2: Add CPZS@B-0.1 to the beaker, with a mass percentage of 5-25%;

[0059] Step 3: Add Span 80 to the beaker at a mass percentage of 2%.

[0060] Step 4: Disperse the nanofluid fuel uniformly by ultrasonic dispersion for 10 minutes (100W, 20℃).

[0061] This embodiment uses a suspended droplet pulse ignition experimental device and a high-speed camera to measure the ignition and combustion characteristics of 5-25% CPZS@B-0.1 / RP-3 nanofluid fuels. The ignition and combustion results for fuels containing 20% ​​CPZS@B-0.1 / RP-3 are also listed.

[0062] like Figure 3 As shown, in this embodiment, RP-3 with 20% CPZS@B-0.1 added has an ignition delay time of 165ms.

[0063] Example 5

[0064] In this embodiment, the nanofluid fuel is configured in the following proportions:

[0065] Step 1: Add 1g of RP-3 to the beaker;

[0066] Step 2: Add CPZS@B-0.5 to the beaker, with a mass percentage of 5-25%;

[0067] Step 3: Add Span 80 to the beaker at a mass percentage of 2%.

[0068] Step 4: Disperse the nanofluid fuel uniformly by ultrasonic dispersion for 10 minutes (100W, 20℃).

[0069] This embodiment uses a suspended droplet pulse ignition experimental device and a high-speed camera to measure the ignition and combustion characteristics of 5-25% CPZS@B-0.5 / RP-3 nanofluid fuels. The ignition and combustion results for fuels containing 20% ​​CPZS@B-0.5 / RP-3 are also listed.

[0070] like Figure 3 As shown, in this embodiment, the RP-3 ignition delay time is 282ms with the addition of 20% CPZS@B-0.5.

[0071] Example 6

[0072] Step 1: Add 1g of RP-3 to the beaker;

[0073] Step 2: Add CPZS@B-1.0 to the beaker, with a mass percentage of 5-25%;

[0074] Step 3: Add Span 80 to the beaker at a mass percentage of 2%.

[0075] Step 4: Disperse the nanofluid fuel uniformly by ultrasonic dispersion for 10 minutes (100W, 20℃).

[0076] This embodiment uses a suspended droplet pulse ignition experimental device and a high-speed camera to measure the ignition and combustion characteristics of 5-25% CPZS@B-1.0 / RP-3 nanofluid fuels. The ignition and combustion results for fuels containing 20% ​​CPZS@B-1.0 / RP-3 are also listed.

[0077] like Figure 3 and 4 As shown, in this embodiment, the ignition delay time of RP-3 with 20% CPZS@B-1.0 added is 393ms, and the combustion duration is 3005ms.

[0078] In summary, this invention utilizes an inorganic heteroatom coating layer for bifunctional catalysis of boron oxidation and hydrocarbon fuel combustion. Starting from the nanostructure of inorganic heteroatom carbon-based coatings of boron, a novel synthetic strategy for heteroatom carbon-based coated boron particles is synthesized. This strategy can form a heteroatom-based inorganic coating layer to achieve bifunctional catalysis of boron oxidation and hydrocarbon fuel combustion.

[0079] The above-described specific implementations can be partially adjusted by those skilled in the art in different ways without departing from the principles and purpose of the present invention. The scope of protection of the present invention is defined by the claims and is not limited to the above-described specific implementations. All implementation schemes within the scope of the claims are bound by the present invention.

Claims

1. A boron-based nanofluid fuel with bifunctional catalytic combustion, characterized in that, It consists of RP-3 kerosene as the base fuel, boron-coated polyphosphononitrile carbonized (CPZS@B) as a nanoparticle additive, and Span 80 as a surfactant. The mass ratio of the described boron-coated polyphosphazene carbon (CPZS@B) to the base fuel is 5-25%, and the mass ratio of Span 80 to the base fuel is 2%. The aforementioned carbonized polyphosphononitrile-coated boron nanoparticles are prepared by the following method: Step 1: Disperse boron powder in acetonitrile solvent and add triethylamine; Step 2: Further add hexachlorocyclotriphosphazene and 4,4'-dihydroxydiphenyl sulfone, and carry out polycondensation reaction under ultrasonic heating environment. Specifically, the polycondensation reaction is carried out in water with ultrasonic power of 100W and temperature of 50℃ for 5 hours. After the reaction is completed, the reaction product is washed 3 times each with ethanol and water, and then freeze-dried at -60℃ for 72 hours to obtain the gray solid product polyphosphazene. Step 3: After encapsulating B nanospheres with the polyphosphazene product obtained in Step 2, carbonize the product to obtain carbonized polyphosphazene-encapsulated B nanospheres (CPZS@B); The carbonization process refers to: raising the temperature from room temperature to 500℃ at a rate of 5℃ / min under a high-purity nitrogen atmosphere and maintaining the temperature for 5 hours, then raising the temperature to the target temperature of 700℃ at a rate of 5℃ / min and maintaining the temperature for 2 hours.

2. The boron-based nanofluid fuel with dual-functional catalytic combustion according to claim 1, characterized in that, The high-purity nitrogen atmosphere refers to a nitrogen flow rate of 100 mL / min, with three separate vacuuming and nitrogen filling cycles.

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