A method for increasing the boiling point temperature of methane propellant

Abstract

The present invention discloses a method for increasing the boiling point temperature of methane propellant, which relates to the field of cryogenic propellants. The method comprises: separating the carbon dioxide component in the Martian atmosphere and converting it into a liquid state, which is stored in a carbon dioxide storage tank; converting part of the liquid carbon dioxide in the carbon dioxide storage tank into a product gas containing gaseous methane; separating and purifying the product gas to obtain high-purity methane gas, converting it into liquid methane, and storing it in a methane storage tank; uniformly mixing the liquid carbon dioxide in the carbon dioxide storage tank with the liquid methane in the methane storage tank; and transporting the mixed product to a spacecraft tank via a pipeline. The overall boiling point temperature of the methane propellant containing liquid carbon dioxide is increased, thereby reducing the evaporation loss of the propellant during the spacecraft's navigation. In the in-situ preparation process of methane propellant on the Martian surface, the present invention utilizes captured liquid carbon dioxide as an additive medium to increase the boiling point of the methane propellant, and achieves the set target according to the colligative principle.

Description

Technical Field

[0001] The present invention relates to the field of cryogenic propellants, in particular to a method for increasing the boiling point temperature of methane propellants. Background Art

[0002] With the successive launch of deep space exploration missions like the lunar and Mars missions, cryogenic propellants such as liquid oxygen and liquid methane have garnered increasing attention. However, the relatively low boiling point of cryogenic propellants like liquid methane makes them highly susceptible to evaporation in the complex thermal environment of space, causing tank pressure to rise until it reaches a safe setpoint, requiring pressure relief and propellant loss. Therefore, the boiling point of the propellant is a fundamental factor influencing the amount of propellant evaporation in a storage system. A higher boiling point can reduce the propellant's cooling requirements and, combined with active and passive thermal management measures, extend the on-orbit storage time of cryogenic propellants.

[0003] Currently, existing research focuses on methane / ethane blends. While this combination can raise the boiling point, the addition of ethane increases the risk of carbon deposition and coking, limiting its potential for practical application. Therefore, the key question is how to increase the boiling point of methane propellants without significant side effects, combining in-situ preparation techniques for missions like Mars exploration. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for increasing the boiling point temperature of methane propellant for the Martian environment. During the in-situ preparation process of methane propellant on the Martian surface, captured liquid carbon dioxide is used as an additive medium for increasing the boiling point of methane propellant, and the set target is achieved according to the colligative principle.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention to solve the technical problems is:

[0006] The present invention provides a method for increasing the boiling point temperature of methane propellant, which is as follows:

[0007] S1. Separate the carbon dioxide component in the Martian atmosphere and convert it into liquid form, which is then stored in a carbon dioxide tank.

[0008] S2, converting part of the liquid carbon dioxide in the carbon dioxide storage tank into a product gas containing gaseous methane;

[0009] S3, separating and purifying the product gas to obtain high-purity methane gas, converting it into liquid methane, and storing it in a methane storage tank;

[0010] S4, mixing the liquid carbon dioxide in the carbon dioxide storage tank and the liquid methane in the methane storage tank uniformly in proportion;

[0011] S5. The mixed product in S4 is transported to the spacecraft tank through a pipeline. The overall boiling point temperature of the methane propellant containing liquid carbon dioxide increases, thereby reducing the evaporation loss of the propellant during the spacecraft's navigation.

[0012] Preferably, in S1, the Martian atmosphere is captured by freezing, adsorption or pressurized liquefaction, and the carbon dioxide component therein is separated.

[0013] Preferably, the liquefaction cold energy of the carbon dioxide gas and methane gas adopts the Martian atmosphere.

[0014] Preferably, in S2, liquid carbon dioxide is converted into a product gas containing gaseous methane by a Sabatier reaction.

[0015] Preferably, in S3, high-purity methane gas is obtained from the product gas by adsorbent or membrane separation.

[0016] Preferably, in S4, a low-temperature stirring device is used to uniformly dissolve the liquid carbon dioxide into the liquid methane.

[0017] Preferably, the methane propellant boiling point temperature raising method is implemented based on a methane propellant boiling point temperature raising device; the methane propellant boiling point temperature raising device includes a carbon dioxide pipeline, a filter, a booster fan, a first stop valve, a frozen capture chamber, a thermostat, a cryogenic refrigerator, a capture unit, a power supply, a power cord, a second stop valve, a third stop valve, a carbon dioxide liquefier, a liquid carbon dioxide storage tank, a fourth stop valve, a converter cooling end, a converter reaction end, a high heat transfer heat element, a fifth stop valve, a product gas pipeline, a purifier, a methane liquefier, a liquid methane storage tank, a propellant delivery pipeline, a sixth stop valve, a mixer, a seventh stop valve and a cryogenic pump;

[0018] The carbon dioxide pipeline is connected in sequence to the filter, the booster fan, the first stop valve, the refrigerated capture chamber, the third stop valve, the carbon dioxide liquefier, the liquid carbon dioxide storage tank, the fourth stop valve, the converter cooling end, and the converter reaction end. A branch is provided on the carbon dioxide pipeline between the refrigerated capture chamber and the third stop valve, and a second stop valve is provided on the branch.

[0019] The cold head of the cryogenic refrigerator is located in a refrigerated capture cabin, and the main body of the cryogenic refrigerator is located in a constant temperature box; the capture unit is located in the refrigerated capture cabin, one side of which is connected to the cold head of the cryogenic refrigerator, and the other side is connected to a power supply via a power cord; the converter cooling end and the converter reaction end are connected via a high heat transfer heat element;

[0020] The converter reaction end is connected to the purifier, methane liquefier, and liquid methane storage tank in sequence through a product gas pipeline;

[0021] The front end of the propellant delivery pipeline includes two branches. The liquid methane storage tank is connected to the mixer through the first branch provided with a sixth shut-off valve, and the liquid carbon dioxide storage tank is connected to the mixer through the second branch provided with a seventh shut-off valve. The mixer is connected to the cryogenic pump and the external spacecraft tank in sequence through the propellant delivery pipeline.

[0022] It should be noted that, in the absence of any conflict between the various technical features in the above preferred embodiments,

[0023] All can be combined without limitation.

[0024] Compared with the prior art, the present invention has the following outstanding and beneficial technical effects: in response to the problem of excessive evaporation loss of methane propellant in the context of missions such as Mars exploration, a method is proposed to use carbon dioxide in the Martian atmosphere to increase the boiling point temperature of methane propellant. Since liquid carbon dioxide is soluble in liquid methane, when liquid carbon dioxide is added to liquid methane to form a dilute solution, interaction occurs between methane molecules and carbon dioxide molecules. This interaction makes it more difficult for methane molecules to escape (evaporate), thereby increasing the boiling point of the mixed methane propellant, and the degree of increase in the boiling point is proportional to the molar concentration of carbon dioxide. In addition, since carbon dioxide is abundant in resources and has stable performance, it will not cause coking or carbon deposition problems, which is conducive to promotion and application.

[0025] The concept, specific structure and technical effects of the present invention will be further described below in conjunction with the accompanying drawings to fully understand the purpose, characteristics and effects of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The present invention is a flow chart of a method for increasing the boiling point temperature of a methane propellant;

[0027] Figure 2 This is a schematic diagram of a device for increasing the boiling point temperature of a methane propellant;

[0028] In the figure: carbon dioxide pipeline 1, filter 2, booster fan 3, first stop valve 4, frozen capture chamber 5, constant temperature box 6, low-temperature refrigerator 7, capture unit 8, power supply 9, power line 10, second stop valve 11, third stop valve 12, carbon dioxide liquefier 13, liquid carbon dioxide storage tank 14, fourth stop valve 15, converter cooling end 16, converter reaction end 17, high heat transfer heat element 18, fifth stop valve 19, product gas pipeline 20, purifier 21, methane liquefier 22, liquid methane storage tank 23, propellant delivery pipeline 24, sixth stop valve 25, mixer 26, seventh stop valve 27, cryogenic pump 28. DETAILED DESCRIPTION

[0029] The present invention will be further described and illustrated below with reference to the accompanying drawings and specific embodiments. The technical features of each embodiment of the present invention may be combined accordingly, provided that there is no conflict between them.

[0030] like Figure 1 As shown, a method for increasing the boiling point temperature of methane propellant provided by the present invention mainly comprises the following steps:

[0031] S1. Capture the Martian atmosphere in batches, separate the carbon dioxide component in the Martian atmosphere, convert it into liquid, and store it in a high-insulation low-temperature carbon dioxide storage tank.

[0032] In a preferred embodiment of the present invention, the Martian atmosphere is captured through freezing, adsorption, or pressurized liquefaction, and the carbon dioxide component is separated to obtain high-purity carbon dioxide. The carbon dioxide gas can be liquefied using Martian atmosphere, achieving liquefaction without incurring additional power consumption.

[0033] S2. Converting part of the liquid carbon dioxide in the obtained carbon dioxide storage tank into a product gas containing gaseous methane through a specific reaction.

[0034] As a preferred embodiment of the present invention, liquid carbon dioxide can be converted into product gas containing gaseous methane through methods such as the Sabatier reaction.

[0035] S3. Separate and purify the obtained product gas to obtain high-purity methane gas, convert it into liquid methane, and store it in a high-insulation low-temperature methane storage tank.

[0036] The "high purity" methane gas here refers to the purity of the methane in the obtained product gas.

[0037] As a preferred embodiment of the present invention, the high-purity methane gas can be liquefied using the Martian atmosphere without generating additional power consumption. High-purity methane gas can be obtained from the product gas through adsorbents or membrane separation.

[0038] S4. Evenly mixing the liquid carbon dioxide in the obtained carbon dioxide storage tank and the liquid methane in the obtained methane storage tank in a specific ratio.

[0039] As a preferred embodiment of the present invention, liquid carbon dioxide can be uniformly dissolved in liquid methane using a low-temperature stirring device, thereby increasing the boiling point of the methane propellant.

[0040] S5. The mixed product in S4 (i.e., methane containing liquid carbon dioxide) is transported to the spacecraft tank through a pipeline. The overall boiling point temperature of the methane propellant containing liquid carbon dioxide increases, thereby reducing the propellant evaporation loss during the spacecraft's navigation.

[0041] As a preferred embodiment of the present invention, the method for increasing the boiling point temperature of methane propellant of the present invention can be implemented based on a device for increasing the boiling point temperature of methane propellant. Figure 2 As shown, the methane propellant boiling point temperature raising device mainly includes a carbon dioxide pipeline 1, a filter 2, a booster fan 3, a first stop valve 4, a frozen capture chamber 5, a constant temperature box 6, a low-temperature refrigerator 7, a capture unit 8, a power supply 9, a power line 10, a second stop valve 11, a third stop valve 12, a carbon dioxide liquefier 13, a liquid carbon dioxide storage tank 14, a fourth stop valve 15, a converter cooling end 16, a converter reaction end 17, a high heat transfer heat element 18, a fifth stop valve 19, a product gas pipeline 20, a purifier 21, a methane liquefier 22, a liquid methane storage tank 23, a propellant delivery pipeline 24, a sixth stop valve 25, a mixer 26, a seventh stop valve 27 and a cryogenic pump 28.

[0042] Specifically, the CO2 pipeline 1 sequentially connects to a filter 2, a booster blower 3, a first shutoff valve 4, a refrigerated capture chamber 5, a third shutoff valve 12, a CO2 liquefier 13, a liquid CO2 storage tank 14, a fourth shutoff valve 15, a converter cooling port 16, and a converter reaction port 17. This system captures and liquefies CO2 from the Martian atmosphere and transports it for reaction. A branch line is located between the refrigerated capture chamber 5 and the third shutoff valve 12, equipped with a second shutoff valve 11. This branch line is used to discharge gases other than CO2 from the Martian atmosphere.

[0043] The cold head portion of the cryogenic refrigerator 7 is located within the refrigerated capture chamber 5, and the main body of the cryogenic refrigerator 7 is located within the constant temperature box 6. The capture unit 8 is located within the refrigerated capture chamber 5, with one side connected to the cold head portion of the cryogenic refrigerator 7 and the other side connected to the power supply 9 via a power cord 10, enabling cooling and heating functions in different operating stages.

[0044] The converter cooling end 16 and the converter reaction end 17 are connected via a high heat transfer element 18, which can transfer the heat generated by the reaction at the converter reaction end 17 to the converter cooling end 16 and be used for vaporizing the liquid carbon dioxide medium.

[0045] The converter reaction end 17 is connected to the purifier 21, the methane liquefier 22, and the liquid methane storage tank 23 in sequence through the product gas pipeline 20. The product gas pipeline 20 is used to separate and liquefy the product gas generated by the reaction to obtain liquid methane.

[0046] The front end of the propellant delivery line 24 includes two branches. The liquid methane storage tank 23 is connected to the mixer 26 via a first branch equipped with a sixth shut-off valve 25. The liquid carbon dioxide storage tank 14 is connected to the mixer 26 via a second branch equipped with a seventh shut-off valve 27. The mixer 26 is connected to a cryogenic pump 28 and an external spacecraft tank via the propellant delivery line 24, completing the delivery of the mixed methane propellant. The first branch is used to supply liquid methane to the mixer 26, and the second branch is used to supply liquid carbon dioxide to the mixer 26.

[0047] Example

[0048] Based on the above-mentioned methane propellant boiling point temperature raising device, this embodiment provides a methane propellant boiling point temperature raising method (i.e., the operating principle of the methane propellant boiling point temperature raising device), which is as follows:

[0049] It is assumed that all stop valves are in a closed state, and equipment such as the cryogenic refrigerator 7 and the cryogenic pump 28 are in a stopped state.

[0050] (1) Start the low-temperature refrigerator 7. The capture unit 8 begins to cool down under the action of the low-temperature refrigerator 7 and reaches the set temperature. Then, open the first stop valve 4 and the second stop valve 11, and start the booster fan 3. The Martian atmosphere enters the carbon dioxide pipeline 1 under the action of the booster fan 3, and enters the refrigerated capture chamber 5 after passing through the filter 2, the booster fan 3, and the first stop valve 4 in sequence. The Martian atmosphere contacts the capture unit 8 inside the refrigerated capture chamber 5, and the carbon dioxide gas condenses on the surface of the capture unit 8, while the remaining Martian gas is discharged through the second stop valve 11. This step continues until the capture unit 8 captures enough carbon dioxide, and then close the first stop valve 4, the second stop valve 11, the low-temperature refrigerator 7, and the booster fan 3.

[0051] (2) The power supply 9 is started, and the current is transmitted to the capture unit 8 through the power line 10. The capture unit 8 begins to heat up, and the attached solid carbon dioxide is converted into gaseous carbon dioxide, accompanied by an increase in the pressure inside the refrigerated capture chamber 5. Then, the third stop valve 12 is opened. Under the action of pressure, the gaseous carbon dioxide begins to flow out and enters the carbon dioxide liquefier 13 through the third stop valve 12, absorbs the cold energy of the Martian atmosphere to complete liquefaction, and enters the liquid carbon dioxide storage tank 14 for storage.

[0052] (3) The fourth stop valve 15 is opened, and the liquid carbon dioxide from the liquid carbon dioxide storage tank 14 enters the converter cooling end 16, absorbs heat, vaporizes, and enters the converter reaction end 17; the fifth stop valve 19 is opened, and the external high-pressure hydrogen enters the converter reaction end 17 and reacts with the carbon dioxide gas to produce a product gas containing methane. The heat generated by the reaction is transported to the converter cooling end 16 through the high heat transfer heat element 18, and the product gas enters the purifier 21 for purification and separation. The methane gas enters the methane liquefier 22 to absorb cold energy and liquefy, and the remaining impurity gas is discharged into the circulation. The liquefied methane is stored in the liquid methane storage tank 23.

[0053] (4) The sixth stop valve 25 and the seventh stop valve 27 are opened. The liquid methane and liquid carbon dioxide in the liquid methane storage tank 23 and the liquid carbon dioxide storage tank 14 enter the mixer 26 through the propellant delivery pipeline 24 for mixing. The liquid carbon dioxide is evenly dissolved in the methane propellant inside the mixer 26, raising the boiling point of the methane propellant. Subsequently, the cryogenic pump 28 is started to deliver the mixed propellant in the mixer 26 to the spacecraft tank.

[0054] The embodiment described above is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Persons skilled in the art may make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, any technical solution obtained by equivalent substitution or equivalent transformation falls within the scope of protection of the present invention.

Claims

1. A method for increasing the boiling point temperature of methane propellant, characterized in that: The details are as follows: S1. Separate the carbon dioxide component in the Martian atmosphere and convert it into liquid form, which is then stored in a carbon dioxide tank. S2, converting part of the liquid carbon dioxide in the carbon dioxide storage tank into a product gas containing gaseous methane; S3, separating and purifying the product gas to obtain high-purity methane gas, converting it into liquid methane, and storing it in a methane storage tank; S4, mixing the liquid carbon dioxide in the carbon dioxide storage tank and the liquid methane in the methane storage tank uniformly in proportion; S5. The mixed product in S4 is transported to the spacecraft tank through a pipeline. The overall boiling point temperature of the methane propellant containing liquid carbon dioxide increases, thereby reducing the evaporation loss of the propellant during the spacecraft's navigation.

2. The method for increasing the boiling point temperature of methane propellant according to claim 1, characterized in that: In the S1, the Martian atmosphere is captured by freezing, adsorption or pressurized liquefaction, and the carbon dioxide component therein is separated.

3. The method for increasing the boiling point temperature of methane propellant according to claim 1, characterized in that: The liquefaction cold energy of the carbon dioxide component and the methane gas utilizes the Martian atmosphere.

4. The method for increasing the boiling point temperature of methane propellant according to claim 1, characterized in that: In S2, liquid carbon dioxide is converted into a product gas containing gaseous methane through a Sabatier reaction.

5. The method for increasing the boiling point temperature of methane propellant according to claim 1, characterized in that: In S3, high-purity methane gas is obtained from the product gas through adsorbent or membrane separation.

6. The method for increasing the boiling point temperature of methane propellant according to claim 1, characterized in that: In S4, a low-temperature stirring device is used to uniformly dissolve the liquid carbon dioxide in the liquid methane.

7. The method for increasing the boiling point temperature of methane propellant according to claim 1, characterized in that: The methane propellant boiling point temperature raising method is realized based on a methane propellant boiling point temperature raising device; the methane propellant boiling point temperature raising device comprises a carbon dioxide pipeline (1), a filter (2), a booster fan (3), a first stop valve (4), a freezing capture chamber (5), a thermostat (6), a cryogenic refrigerator (7), a capture unit (8), a power supply (9), a power line (10), a second stop valve (11), a third stop valve (12), a carbon dioxide liquefier (13), a liquid carbon dioxide storage tank (14), a fourth stop valve (15), a converter cooling end (16), a converter reaction end (17), a high heat transfer heat element (18), a fifth stop valve (19), a product gas pipeline (20), a purifier (21), a methane liquefier (22), a liquid methane storage tank (23), a propellant delivery pipeline (24), a sixth stop valve (25), a mixer (26), a seventh stop valve (27) and a cryogenic pump (28); The carbon dioxide pipeline (1) is connected in sequence to the filter (2), the booster fan (3), the first stop valve (4), the refrigerated capture chamber (5), the third stop valve (12), the carbon dioxide liquefier (13), the liquid carbon dioxide storage tank (14), the fourth stop valve (15), the converter cooling end (16), and the converter reaction end (17); a branch is further provided on the carbon dioxide pipeline (1) between the refrigerated capture chamber (5) and the third stop valve (12), and a second stop valve (11) is provided on the branch; The cold head portion of the cryogenic refrigerator (7) is located in the freezing capture chamber (5), and the main body of the cryogenic refrigerator (7) is located in the constant temperature box (6); the capture unit (8) is located in the freezing capture chamber (5), one side of which is connected to the cold head of the cryogenic refrigerator (7), and the other side of which is connected to the power supply (9) through a power line (10); the converter cooling end (16) and the converter reaction end (17) are connected through a high heat transfer element (18); The converter reaction end (17) is connected to the purifier (21), the methane liquefier (22), and the liquid methane storage tank (23) in sequence through the product gas pipeline (20); The front end of the propellant delivery pipeline (24) includes two branches. The liquid methane storage tank (23) is connected to the mixer (26) through the first branch provided with a sixth stop valve (25), and the liquid carbon dioxide storage tank (14) is connected to the mixer (26) through the second branch provided with a seventh stop valve (27). The mixer (26) is connected to the cryogenic pump (28) and the external spacecraft tank in sequence through the propellant delivery pipeline (24).

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