Combustion catalyst, solid fuel, and hybrid rocket fuel

Abstract

To provide a combustion catalyst for enhancing the combustion efficiency of polymer material, a solid fuel with superior combustion efficiency, and a hybrid rocket fuel with superior fuel regression rate.SOLUTION: A combustion catalyst comprises vanadium oxide and is used for combustion of polymer material. A solid fuel comprises polymer material and vanadium oxide. A hybrid rocket fuel comprises the solid fuel.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a combustion catalyst, a solid fuel, and a hybrid rocket fuel.

Background Art

[0002] Hybrid rockets have attracted attention as thrust sources for space transportation vehicles and propulsion devices such as thrusters for artificial satellites. A hybrid rocket generally uses a solid fuel and a liquid or gaseous oxidizer as propellants. Since the phases of the fuel and the oxidizer are different, mixing and combustion do not easily occur, and the management of the propellants is easier than that of solid rockets and liquid rockets. Among them, a hybrid rocket using a polymer as a solid fuel is easy to manage during storage and transportation.

[0003] As a solid fuel for hybrid rockets, a low melting point thermoplastic (LT) fuel is known (see, for example, Patent Document 1). The LT fuel has a high fuel regression rate and excellent mechanical properties and adhesiveness.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, the LT fuel of Patent Document 1 still has a relatively low fuel regression rate as a solid fuel for hybrid rockets, and a higher fuel regression rate has been demanded.

[0006] The present invention has been made in view of the above circumstances, and an object thereof is to provide a combustion catalyst that improves the combustion efficiency of a polymer material, a solid fuel having excellent combustion efficiency, and a hybrid rocket fuel having an excellent fuel regression rate. [Means for solving the problem]

[0007] The present invention has the following aspects. [1] A combustion catalyst made of vanadium oxide and used in the combustion of polymeric materials. [2] The combustion catalyst according to [1], wherein the vanadium oxide is vanadium pentoxide. [3] A solid fuel comprising a polymer material and vanadium oxide. [4] The solid fuel according to [3], wherein the vanadium oxide is vanadium pentoxide. [5] The solid fuel according to [3], wherein the content of the vanadium oxide per 100 parts by mass of the polymer material is 10 parts by mass or less. [6] The solid fuel described in [3], wherein the polymer material is a low melting point thermoplastic resin fuel. [7] A hybrid rocket fuel comprising the solid fuel described in any one of [3] to [6]. Effect of the Invention

[0008] According to the present invention, it is possible to provide a combustion catalyst that improves the combustion efficiency of polymer materials, a solid fuel with excellent combustion efficiency, and a hybrid rocket fuel with excellent fuel regression rate. [Brief description of the drawings]

[0009] [Figure 1] FIG. 13 is a diagram showing the results of a solid fuel combustion experiment. [Diagram 2] FIG. 13 is a diagram showing the results of a solid fuel combustion experiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] An embodiment of the combustion catalyst, solid fuel, and hybrid rocket fuel of the present invention will be described. It should be noted that the present embodiment is specifically described to allow a better understanding of the gist of the invention, and does not limit the present invention unless otherwise specified.

[0011] [Combustion catalyst] A combustion catalyst according to one embodiment of the present invention is made of vanadium oxide and is used for the combustion of polymer materials.

[0012] Vanadium oxide includes vanadium pentoxide (V 2 O 5 ), vanadium trioxide (V 2 O 3 ), vanadium dioxide (VO 2 ) etc.

[0013] The amount of vanadium oxide added to the polymeric material is preferably 0.1 parts by mass or more and 15 parts by mass or less per 100 parts by mass of the polymeric material. Furthermore, if the lower limit of the amount of vanadium oxide added relative to 100 parts by mass of the polymer material is 0.1 parts by mass or more, the combustion efficiency of the polymer material is improved.

[0014] According to the combustion catalyst of this embodiment, when added to a polymer material, it is possible to improve the combustion efficiency of the polymer material more than ever before.

[0015] [Solid fuel] A solid fuel according to one embodiment of the present invention includes a polymer material and vanadium oxide.

[0016] Examples of polymeric materials include, but are not limited to, thermoplastic resins such as styrene-based thermoplastic elastomers, polystyrene-poly(ethylene / propylene) block (SEP), polystyrene-poly(ethylene / propylene) block-polystyrene (SEEPS), SBC (styrene-butadiene-styrene copolymer), SEBC (styrene-ethylene-propylene-styrene copolymer), acrylic resin, high density polyethylene, ABS (acrylonitrile-butadiene-styrene), paraffin, stearic acid, xylene resin, low melting point thermoplastic resin fuel, and the like, and thermosetting resins such as glycidyl azide polymer and hydroxyl-terminated polybutadiene polymer. Thermoplastic resins also function as hardeners for solid fuels.

[0017] Low melting point thermoplastic (LT) fuel has excellent mechanical properties and adhesiveness, and has a fuel regression rate equivalent to that of conventional paraffin (WAX) fuel. In addition, since LT fuel is a synthetic resin composed of multiple resins, it is possible to change the mechanical properties and fuel regression rate by changing the blending ratio of the constituent resins. When the solid fuel of this embodiment is used as the solid fuel (hybrid rocket fuel) of a hybrid rocket, LT fuel is preferable as the thermoplastic resin.

[0018] The glycidyl azide polymer is obtained by urethane polymerization of a prepolymer. Since the glycidyl azide polymer has two to four hydroxyl groups, it is called a di-ol glycidyl azide polymer, a tri-ol glycidyl azide polymer, or a tetra-ol glycidyl azide polymer, and the more hydroxyl groups there are, the more likely it is that a urethane bond will be formed three-dimensionally. Therefore, in the synthesis of the tetra-ol glycidyl azide polymer, a crosslinking agent used to improve moldability during the synthesis of the di-ol glycidyl azide polymer and the tri-ol glycidyl azide polymer is not required. When the solid fuel of this embodiment is used as the solid fuel (hybrid rocket fuel) of a hybrid rocket, the thermosetting resin is preferably a tetra-ol glycidyl azide polymer.

[0019] Hydroxyl-terminated polybutadiene polymers are obtained by urethane polymerization of polybutadiene prepolymers. Hydroxyl-terminated polybutadiene polymers have excellent mechanical properties and adhesive properties, and are primarily used as fuels and binders for solid propellants. In addition, because of their particularly excellent mechanical properties, hydroxyl-terminated polybutadiene polymers are preferred as thermosetting resins for use in solid fuels for larger hybrid rockets.

[0020] Vanadium oxide includes vanadium pentoxide (V 2 O 5 ), vanadium trioxide (V 2O 3 ), vanadium dioxide (VO 2 ) etc.

[0021] In the solid fuel of this embodiment, the content of vanadium oxide per 100 parts by mass of the polymer material is preferably 0.1 parts by mass or more and 15 parts by mass or less. Furthermore, if the lower limit of the content of vanadium oxide relative to 100 parts by mass of the polymer material is 0.1 parts by mass or more, the combustion efficiency of the polymer material is improved.

[0022] The solid fuel of the present embodiment may contain process oil. Examples of the process oil include mineral oils such as naphthenic oil and paraffinic oil.

[0023] The solid fuel of this embodiment preferably has mechanical properties sufficient to accommodate the expansion of the fuel gas generation chamber of the hybrid rocket that may occur during combustion of the solid fuel.

[0024] Tensile strength is one index that indicates the mechanical properties of solid fuel. The tensile strength is preferably 0.1 MPa or more, and more preferably 0.8 MPa or less. If the tensile strength is less than the lower limit, the fuel may be destroyed by the acceleration during rocket launch or the impact during transportation.

[0025] The tensile strength of the solid fuel can be measured in accordance with JIS K6251:2017.

[0026] The solid fuel of the present embodiment contains a polymer material and vanadium oxide, and therefore the combustion efficiency of the polymer material can be improved compared to conventional solid fuels.

[0027] [Hybrid rocket fuel] A hybrid rocket fuel according to one embodiment of the present invention includes the solid fuel of the above-described embodiments.

[0028] According to the hybrid rocket fuel of this embodiment, since it contains the solid fuel of the above embodiment, a hybrid rocket fuel with excellent fuel regression rate can be obtained. In particular, when the solid fuel contains LT fuel as a polymer material, most of the aromatic hydrocarbons contained in the LT fuel are adsorbed to the vanadium oxide, and the aromatic hydrocarbons are oxidized by the oxygen of the vanadium oxide. Therefore, it is possible to suppress the aromatic hydrocarbons from hindering the improvement of the fuel regression rate. EXAMPLES

[0029] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples.

[0030] [Example 1] <Preparation of solid fuel> 99% by mass of low melting point thermoplastic resin (LT) was heated at 120°C and degassed, then mixed with 1% by mass of vanadium pentoxide, and the mixture was cooled and hardened to obtain a solid fuel.

[0031] <Solid fuel combustion experiment in a combustor> A 90mm long solid fuel was prepared and loaded into a 25mm diameter combustor. The combustor was sealed, and the solid fuel was ignited using an ignition device with a nichrome wire at a pressure of about 3MPa, and the solid fuel was burned on the inner end surface in the fuel gas generation chamber inside the combustor. The results of the combustion experiment are shown in Figures 1 and 2.

[0032] [Comparative Example 1] <Preparation of solid fuel> A solid fuel consisting only of low melting point thermoplastic resin (LT) was prepared.

[0033] <Solid fuel combustion experiment in a combustor> A solid fuel combustion experiment was carried out in the same manner as in Example 1. The results of the combustion experiment are shown in Figs.

[0034] From the results shown in FIG. 1, it was found that the solid fuel containing the low melting point thermoplastic resin (LT) and vanadium pentoxide in Example 1 had a fuel regression rate that was 27% higher than the solid fuel consisting of only the low melting point thermoplastic resin (LT) in Comparative Example 1.

[0035] [Example 2] <Preparation of solid fuel> A solid fuel was obtained in the same manner as in Example 1, except that the vanadium pentoxide content was 0.1 mass %.

[0036] <Solid fuel combustion experiment in a combustor> A solid fuel combustion experiment was carried out in the same manner as in Example 1. The results of the combustion experiment are shown in FIG.

[0037] [Example 3] <Preparation of solid fuel> A solid fuel was obtained in the same manner as in Example 1, except that the vanadium pentoxide content was 0.5 mass %.

[0038] <Solid fuel combustion experiment in a combustor> A solid fuel combustion experiment was carried out in the same manner as in Example 1. The results of the combustion experiment are shown in Figs.

[0039] [Example 4] <Preparation of solid fuel> A solid fuel was obtained in the same manner as in Example 1, except that the vanadium pentoxide content was 2 mass %.

[0040] <Solid fuel combustion experiment in a combustor> A solid fuel combustion experiment was carried out in the same manner as in Example 1. The results of the combustion experiment are shown in Figs.

[0041] [Example 5] <Preparation of solid fuel> A solid fuel was obtained in the same manner as in Example 1, except that the vanadium pentoxide content was 5 mass %.

[0042] <Solid fuel combustion experiment in a combustor> A solid fuel combustion experiment was carried out in the same manner as in Example 1. The results of the combustion experiment are shown in Figs.

[0043] [Example 6] <Preparation of solid fuel> A solid fuel was obtained in the same manner as in Example 1, except that the vanadium pentoxide content was 10 mass %.

[0044] <Solid fuel combustion experiment in a combustor> A solid fuel combustion experiment was carried out in the same manner as in Example 1. The results of the combustion experiment are shown in Figs.

[0045] [Comparative Example 2] <Preparation of solid fuel> A solid fuel was obtained in the same manner as in Example 1, except that the vanadium pentoxide content was 15 mass %.

[0046] <Solid fuel combustion experiment in a combustor> A solid fuel combustion experiment was carried out in the same manner as in Example 1. The results of the combustion experiment are shown in Figs.

[0047] From the results shown in Figure 2, it was confirmed that if the vanadium pentoxide content in the solid fuel is between 1% and 2% by mass, the combustibility of the solid fuel follows the theoretical value. At 2% by mass or more, a decrease in the theoretical value is observed, and at 15% by mass, the theoretical value decreases by about 3%. Therefore, it is desirable to keep the performance decrease to about 1%, and it is preferable for the vanadium pentoxide content to be 10% by mass or less. In Figure 2, the vertical axis represents the characteristic exhaust speed, and the horizontal axis represents the equivalence ratio.

Claims

1. A combustion catalyst made of vanadium oxide and used in the combustion of polymeric materials.

2. 2. The combustion catalyst of claim 1, wherein the vanadium oxide is vanadium pentoxide.

3. A solid fuel comprising a polymeric material and vanadium oxide.

4. The solid fuel according to claim 3 , wherein the vanadium oxide is vanadium pentoxide.

5. The solid fuel according to claim 3 , wherein the content of the vanadium oxide is 10 parts by mass or less per 100 parts by mass of the polymer material.

6. The solid fuel of claim 3 , wherein the polymeric material is a low melting point thermoplastic fuel.

7. A hybrid rocket fuel comprising the solid fuel according to any one of claims 3 to 6.

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