Refrigerating system for Mars in-situ propellant preparation and storage process

Abstract

The invention provides a refrigerating system for a Mars in-situ propellant preparation and storage process, which comprises a gas-liquid separation storage tank, a compressor, an aftercooler, a heat regenerator, a first throttle valve, a carbon dioxide capture module, a liquid oxygen storage tank, a liquid methane storage tank and a fan, and is characterized in that the heat regenerator comprises a high-pressure refrigerant flow channel, a low-pressure refrigerant flow channel, an oxygen flow channel and a methane flow channel; gaseous oxygen is liquefied in the oxygen flow channel and then stored in the liquid oxygen storage tank, and gaseous methane is liquefied in the methane flow channel and then stored in the liquid methane storage tank; the carbon dioxide capturing module comprises a refrigerant flow channel and a carbon dioxide flow channel, a refrigerant of the refrigerant flow channel is used for providing cooling capacity for carbon dioxide freezing capturing, fluid of the carbon dioxide flow channel is Mars atmosphere, and the Mars atmosphere is introduced into the carbon dioxide capturing module through a fan. According to the refrigerating system, integrated cooling of carbon dioxide capture, methane liquefaction and oxygen liquefaction can be achieved, and the complexity of system configuration is reduced.

Description

Technical Field

[0001] The present invention relates to the field of Mars exploration technology, and in particular to a refrigeration system for an in-situ propellant storage process on Mars. Background Art

[0002] In-situ propellant preparation on Mars refers to the use of natural resources on Mars to prepare propellant for launch vehicles on-site on Mars. Compared with the method of carrying propellant and life supplies from Earth, it can avoid the huge size and resource consumption of rockets during the launch phase. It is an important means to achieve frequent round-trip travel between Earth and Mars for Mars exploration in the future.

[0003] The carbon dioxide content in the Martian atmosphere is over 95%. By enriching carbon dioxide and combining it with Martian water resources, methane and oxygen propellants can be produced in situ through the well-established Sabatier reaction or electrochemical reactions. Oxygen can be used as a life support for future manned landings on Mars. In-situ production of methane and oxygen propellants can reduce the mass of landers by over 90%, significantly reducing the size of rocket launches and is a key technology for the sustainable development of deep space exploration.

[0004] The preparation process of Mars in-situ propellant involves three important links, namely carbon dioxide capture, methane liquefaction and oxygen liquefaction. In the existing Mars in-situ propellant preparation scheme, when carbon dioxide capture adopts the freezing capture method, the existing preparation system usually needs to set up refrigerators for carbon dioxide capture, methane liquefaction and oxygen liquefaction respectively, resulting in a large number of refrigerators and a complex overall structure, which greatly reduces the utilization rate of the refrigerators. Summary of the Invention

[0005] The present invention provides a refrigeration system for the in-situ propellant storage process on Mars, which is used to solve the defect in the prior art that refrigeration machines are separately provided for carbon dioxide capture, methane liquefaction and oxygen liquefaction, resulting in complex structural configuration. It realizes the integrated cooling of carbon dioxide capture, methane liquefaction and oxygen liquefaction, provides an integrated refrigeration system, and simplifies the structural configuration.

[0006] The present invention provides a refrigeration system for an in-situ propellant storage process on Mars, comprising: The gas-liquid separation storage tank, compressor, aftercooler, regenerator and first throttle valve are connected in sequence, and also include a carbon dioxide capture module, liquid oxygen storage tank, liquid methane storage tank and fan; The regenerator includes a high-pressure refrigerant flow channel, a low-pressure refrigerant flow channel, an oxygen flow channel, and a methane flow channel. The gaseous oxygen is liquefied in the oxygen flow channel and then stored in the liquid oxygen storage tank. The gaseous methane is liquefied in the methane flow channel and then stored in the liquid methane storage tank. The carbon dioxide capture module includes a refrigerant flow channel and a carbon dioxide flow channel. The refrigerant in the refrigerant flow channel is used to provide cold energy for carbon dioxide freezing and capture. The fluid in the carbon dioxide flow channel is Martian atmosphere, which is introduced into the carbon dioxide capture module through the fan. The outlet of the compressor is connected to the inlet of the aftercooler, and the outlet of the aftercooler is connected in sequence to the high-pressure refrigerant flow channel and the first throttle valve of the regenerator. The refrigerant after passing through the first throttle valve enters the carbon dioxide capture module or enters the low-pressure refrigerant flow channel of the regenerator. The carbon dioxide capture module is arranged on the low-pressure refrigerant side, and the refrigerant outlet of the carbon dioxide capture module is connected to the inlet of the low-pressure refrigerant flow channel of the regenerator. The low-pressure refrigerant outlet of the regenerator is connected to the gas-liquid separation tank, and the gas phase separated by the gas-liquid separation tank enters the compressor.

[0007] According to a refrigeration system for an in-situ propellant storage process on Mars provided by the present invention, the regenerator is provided with one, and the carbon dioxide capture module is arranged between the first throttle valve and the regenerator; or, the regenerator is provided with multiple, and the carbon dioxide capture module is arranged between any two regenerators.

[0008] According to the present invention, a refrigeration system for the in-situ propellant storage process on Mars is provided. The carbon dioxide capture module includes multiple parallel sub-modules, some of which have a refrigeration working mode to freeze and capture carbon dioxide, and other sub-modules have a heating working mode to heat the condensed pure carbon dioxide to cause it to sublime and pressurize. The refrigeration working mode and the heating working mode are performed alternately.

[0009] According to the present invention, a refrigeration system for the in-situ propellant storage process on Mars is provided. The inlet end of each submodule is connected to a first valve and the outlet end is connected to a second valve. The first valve is connected to the Martian atmosphere pipeline. In the cooling working mode, the first valve and the second valve are opened. In the heating working mode, the first valve and the second valve are closed.

[0010] According to a refrigeration system for an in-situ propellant storage process on Mars provided by the present invention, a supercharger is provided at the inlet end of the carbon dioxide capture module, and the Martian atmosphere enters the carbon dioxide capture module after being pressurized by the supercharger.

[0011] According to the present invention, a refrigeration system for an in-situ propellant storage process on Mars is provided, wherein the refrigeration system further includes a cold energy recovery device connected to the carbon dioxide capture module, for recovering cold energy of uncondensed gas.

[0012] According to the present invention, a refrigeration system for the in-situ propellant preparation and storage process on Mars is provided. The refrigerant adopts a non-azeotropic mixed refrigerant, including: neon with a molar fraction of 0-15%; nitrogen with a molar fraction of 10%-30%; methane with a molar fraction of 20%-40%; ethane, ethylene, carbon tetrafluoride and their mixtures with a molar fraction of 10%-30%; propane, isobutane, isopentane and their mixtures with a molar fraction of 10%-30%.

[0013] According to a refrigeration system for an in-situ propellant storage process on Mars provided by the present invention, the carbon dioxide capture temperature, the methane liquefaction temperature, and the oxygen liquefaction temperature are all more than 5°C lower than the saturation temperature at the corresponding pressure.

[0014] According to the present invention, a refrigeration system for the in-situ propellant storage process on Mars is provided. The refrigeration system is used directly in the Martian atmosphere and is suitable for use in a non-constant temperature environment.

[0015] According to the present invention, a refrigeration system for an in-situ propellant storage process on Mars is provided. When the refrigeration system is in operation, any one, two or three functions of carbon dioxide capture, methane liquefaction and oxygen liquefaction can be enabled.

[0016] The refrigeration system provided by the present invention for the in-situ propellant storage process on Mars adopts an integrated refrigeration system, integrating the functions of carbon dioxide capture, methane liquefaction and oxygen liquefaction. It can realize carbon dioxide capture, methane liquefaction and oxygen liquefaction simultaneously with a single refrigeration device, eliminating the need to set up multiple refrigerators separately and limit the utilization rate of the refrigerators, thereby expanding the versatility of the refrigeration system.

[0017] The integrated refrigeration system of the present invention adopts a mixed refrigerant heat recovery throttling refrigeration method, achieves a large temperature range refrigeration target through the phase change of refrigerants with different boiling points, realizes multi-load integrated refrigeration of carbon dioxide freezing capture, methane liquefaction and oxygen liquefaction, simplifies the number of refrigerators and the complexity of system operation; the refrigeration system has a wide cooling capacity range and can meet milliwatt to megawatt cooling needs; moreover, the refrigeration system adopts a refrigerant phase change refrigeration method, has high energy density, is easy to achieve lightweight, is convenient to carry to Mars and is conducive to use on Mars. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the present invention or the prior art, a brief introduction is given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0019] Figure 1This is one of the structural schematic diagrams of the refrigeration system provided by the present invention for the in-situ propellant storage process on Mars.

[0020] Figure 2 This is the second structural schematic diagram of the refrigeration system provided by the present invention for the in-situ propellant storage process on Mars.

[0021] Figure 3 It is a structural schematic diagram of the carbon dioxide capture module provided by the present invention.

[0022] Reference numerals: 10. Gas-liquid separation storage tank; 11. Compressor; 12. Aftercooler; 13. Regenerator; 14. First throttle valve; 15. Carbon dioxide capture module; 151. Submodule; 152. First valve; 153. Second valve; 16. Liquid oxygen storage tank; 17. Liquid methane storage tank; 18. Fan; 19. Martian atmosphere pipeline; 20. Gaseous methane pipeline; 21. Gaseous oxygen pipeline; 22. Cold recovery device; 23. Second throttle valve. DETAILED DESCRIPTION

[0023] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0024] like Figures 1 to 3 As shown, the present invention provides a refrigeration system for the in-situ propellant preparation and storage process on Mars, comprising: a gas-liquid separation tank 10, a compressor 11, an aftercooler 12, a regenerator 13 and a first throttle valve 14 connected in sequence; and also comprising a carbon dioxide capture module 15, a liquid oxygen storage tank 16, a liquid methane storage tank 17, a fan 18, a Martian atmosphere pipeline 19, a gaseous methane pipeline 20 and a gaseous oxygen pipeline 21.

[0025] Among them, the Martian atmosphere pipeline 19 is connected to the carbon dioxide capture module 15 through the fan 18, and the air inlet end of the Martian atmosphere pipeline 19 is connected to the Martian atmosphere, and the fan 18 provides air intake power for the Martian atmosphere.

[0026] The gaseous methane line 20 is connected to the liquid methane storage tank 17 through the regenerator 13. The gaseous methane inlet of the gaseous methane line 20 is gaseous methane, which is produced from the carbon dioxide feedstock enriched by the system. The gaseous methane is liquefied and stored in the liquid methane storage tank 17. The gaseous oxygen line 21 is connected to the liquid oxygen storage tank 16 through the regenerator 13. The gaseous oxygen inlet of the gaseous oxygen line 21 is gaseous oxygen, which is produced from the carbon dioxide feedstock enriched by the system. The gaseous oxygen is liquefied and stored in the liquid oxygen storage tank 16. Regarding the methane and oxygen production devices, they can be integrated with the refrigeration system of the present invention. The specific structure and layout will not be elaborated here, and reference can be made to the existing production devices. A second throttle valve 23 can be provided at the inlet of the liquid methane storage tank 17 and the liquid oxygen storage tank 16 to achieve flow and pressure control.

[0027] The regenerator 13 includes a high-pressure refrigerant flow channel, a low-pressure refrigerant flow channel, an oxygen flow channel, and a methane flow channel. Gaseous oxygen is liquefied in the oxygen flow channel and stored in a liquid oxygen storage tank 16. Gaseous methane is liquefied in the methane flow channel and stored in a liquid methane storage tank 17. The regenerator 13 of the present invention provides conditions for carbon dioxide freezing and capture, methane liquefaction, and oxygen liquefaction. One or more regenerators 13 may be provided. For example, the number of regenerators 13 may be determined based on factors such as the heat exchange area of the regenerator 13, the required cooling temperature, and the operating frequency of the compressor 11. This is not limited by the present invention.

[0028] The carbon dioxide capture module 15 includes a refrigerant flow channel and a carbon dioxide flow channel. The refrigerant in the refrigerant flow channel is used to provide cooling capacity for carbon dioxide freezing and capture. The fluid in the carbon dioxide flow channel is the Martian atmosphere, which is connected to the carbon dioxide capture module 15 through the Martian atmosphere pipeline 19. By arranging a fan 18 on the Martian atmosphere pipeline 19, the fan 18 can introduce fresh air during the carbon dioxide condensation process to ensure the carbon dioxide capture efficiency.

[0029] like Figure 1 or Figure 2 The figure shows the refrigerant circulation path in the system, providing the required cooling capacity for carbon dioxide freezing capture, methane liquefaction, and oxygen liquefaction. The outlet of the compressor 11 is connected to the inlet of the aftercooler 12, which is in turn connected to the high-pressure refrigerant flow path of the regenerator 13 and the first throttle valve 14. After passing through the first throttle valve 14, the refrigerant enters the carbon dioxide capture module 15 or the low-pressure refrigerant flow path of the regenerator 13. The carbon dioxide capture module 15 is arranged on the low-pressure refrigerant side. The refrigerant outlet of the carbon dioxide capture module 15 is connected to the low-pressure refrigerant flow path inlet of the regenerator 13. The low-pressure refrigerant outlet of the regenerator 13 is connected to the gas-liquid separation tank 10. The gas phase separated by the gas-liquid separation tank 10 enters the compressor 11.

[0030] The refrigeration system provided by the present invention for the in-situ propellant storage process on Mars adopts an integrated refrigeration system, integrating the functions of carbon dioxide capture, methane liquefaction and oxygen liquefaction. It can realize carbon dioxide capture, methane liquefaction and oxygen liquefaction simultaneously with a single refrigeration device, eliminating the need to set up multiple refrigerators separately and limit the utilization rate of the refrigerators, thereby expanding the versatility of the refrigeration system.

[0031] The integrated refrigeration system of the present invention adopts a mixed refrigerant heat recovery throttling refrigeration method, achieves a large temperature range refrigeration target through the phase change of refrigerants with different boiling points, realizes multi-load integrated refrigeration of carbon dioxide freezing capture, methane liquefaction and oxygen liquefaction, simplifies the number of refrigerators and the complexity of system operation; the refrigeration system has a wide cooling capacity range and can meet milliwatt to megawatt cooling needs; moreover, the refrigeration system adopts a refrigerant phase change refrigeration method, has high energy density, is easy to achieve lightweight, is convenient to carry to Mars and is conducive to use on Mars.

[0032] Among them, the three functions of carbon dioxide freezing capture, methane liquefaction and oxygen liquefaction can be enabled at the same time, or any one or two can be enabled. The three are independent of each other and do not interfere with each other, and can be adjusted according to actual needs.

[0033] The compressor 11 of the present invention can be single-stage, two-stage or three-stage compression, which is not limited in the present invention. The heat dissipation mode of the aftercooler 12 can be forced convection heat dissipation, radiation heat dissipation or a combination thereof, which is not limited in the present invention.

[0034] The regenerator 13 of the present invention may be provided with one or more, such as in one embodiment, Figure 2 As shown, a regenerator 13 is provided, and a carbon dioxide capture module 15 is provided between the first throttle valve 14 and the regenerator 13. The refrigeration system structure and configuration in this embodiment are simple, and are suitable for cooling methane and oxygen to the same temperature.

[0035] In another embodiment, Figure 1 As shown, two regenerators 13 are provided, and the carbon dioxide capture module 15 is arranged between the two regenerators 13, which is suitable for solutions with different cooling temperatures for methane and oxygen.

[0036] It is understandable that in other embodiments, more than two regenerators 13 may be provided, and the carbon dioxide capture module 15 may be adaptively provided between any two regenerators 13 as long as the carbon dioxide capture temperature meets the requirements.

[0037] As a preferred embodiment of the present invention, the carbon dioxide capture module 15 includes a plurality of parallel submodules 151, wherein a portion of the submodules 151 has a refrigeration working mode to freeze and capture carbon dioxide, and another portion of the submodules 151 has a heating working mode to heat the condensed pure carbon dioxide to sublime it and increase its pressure, and the refrigeration working mode and the heating working mode are performed alternately.

[0038] like Figure 3 As shown, the carbon dioxide capture module 15 of the present invention has two working modes: carbon dioxide freezing capture and heating sublimation pressurization. The low-temperature, low-pressure refrigerant provides cooling and then returns to the regenerator 13. The high-temperature, high-pressure refrigerant at the outlet of the compressor 11 provides heat and then returns to the hot end inlet of the high-pressure refrigerant flow channel of the regenerator 13. The above working modes can effectively utilize the cold energy and heat energy of the system, realize carbon dioxide heating and pressurization, and reduce the heat dissipation load of the aftercooler 12.

[0039] The cooling mode and the heating mode can be operated alternately according to a pre-set program, such as switching to the heating mode after running in the cooling mode for a first time, and switching to the cooling mode after running in the heating mode for a second time.

[0040] As a preferred embodiment of the present embodiment, the inlet end of each submodule 151 is connected to a first valve 152 and the outlet end is connected to a second valve 153. The first valve 152 is connected to the Martian atmosphere pipeline 19. In the cooling working mode, the first valve 152 and the second valve 153 are opened. In the heating working mode, the first valve 152 and the second valve 153 are closed.

[0041] For example, Figure 3 The figure shows three submodules 151 in detail. The first submodule 151 is in heating mode, while the second and third submodules 151 are in cooling mode. Each submodule 151 is connected to low-temperature, low-pressure refrigerant and high-temperature, high-pressure refrigerant from the compressor 11 outlet. The operating mode is switched by opening and closing a first valve 152 and a second valve 153. When the low-temperature, low-pressure refrigerant is the working fluid, the system operates in cooling mode. When the high-temperature, high-pressure refrigerant from the compressor 11 outlet is the working fluid, the system operates in heating mode. In heating mode, the high-temperature, high-pressure refrigerant from the compressor 11 outlet performs inter-wall heat exchange with the frozen carbon dioxide. To enhance the heating effect, the first and second valves 152, 153 are closed in heating mode, providing a sealed space for heating the carbon dioxide and achieving both vaporization and self-pressurization. To switch to cooling mode, the first and second valves 152, 153 are opened to allow the Martian atmosphere to communicate with the submodules 151. The first and second valves 152, 153 can be controlled, for example, by electronic valves to flexibly switch between the two operating modes.

[0042] It should be noted that each submodule 151 is a heat exchanger with a large specific surface area, and the structural form of the heat exchanger is not restricted. For example, a microchannel fin tube heat exchanger or a microchannel tube bundle heat exchanger with microchannels can be used to easily expand the heat transfer interface for carbon dioxide freezing and capture, effectively overcoming the defects of the existing Stirling refrigerator, such as the fixed cold head structure and the difficulty in expanding the heat transfer surface, thereby improving the heat exchange capacity and the carbon dioxide capture efficiency.

[0043] In a preferred embodiment of the present invention, a supercharger is installed at the inlet of the CO2 capture module 15. The Martian atmosphere is pressurized by the supercharger before entering the module 15. Because the Martian atmospheric pressure is relatively low, the installation of a supercharger helps increase the Martian atmospheric pressure, thereby increasing the heat transfer coefficient, raising the capture temperature, and reducing the power consumption of the refrigeration system. The supercharger can be a compressor or a booster pump, depending on actual needs.

[0044] As a preferred embodiment of the present invention, Figure 1 or Figure 2 As shown, the refrigeration system further includes a cold recovery device 22 connected to the carbon dioxide capture module 15, which is used to recover the cold of the uncondensed gas, thereby realizing the reuse of cold and saving energy.

[0045] As a preferred embodiment of the present invention, the refrigerant utilizes a non-azeotropic refrigerant mixture comprising: neon at a molar fraction of 0-15%; nitrogen at a molar fraction of 10-30%; methane at a molar fraction of 20-40%; ethane, ethylene, carbon tetrafluoride, and mixtures thereof at a molar fraction of 10-30%; and propane, isobutane, isopentane, and mixtures thereof at a molar fraction of 10-30%. The refrigerant of the present invention achieves a wide temperature range through phase transitions between refrigerants with different boiling points, creating favorable conditions for flexibly setting different carbon dioxide capture temperatures, methane liquefaction temperatures, and oxygen liquefaction temperatures.

[0046] The CO2 capture temperature, methane liquefaction temperature, and oxygen liquefaction temperature can be the same or different, depending on actual needs. Preferably, the CO2 capture temperature, methane liquefaction temperature, and oxygen liquefaction temperature are all at least 5°C lower than the saturation temperature at the corresponding pressure to achieve appropriate CO2 capture efficiency, methane and oxygen storage stability, and safety.

[0047] When used on Mars, conventional refrigeration systems typically require building a constant-temperature cabin on Mars and then operating the refrigeration system in a relatively stable temperature environment within the constant-temperature cabin, involving complex structures and processes. The refrigeration system of the present invention can be used directly in the Martian atmosphere without the need for a constant-temperature cabin. The refrigeration system itself can cope with changes in the Martian ambient temperature and can respond to the impact of the day-night temperature difference on Mars through frequency modulation of compressor 11, heating of the compressor 11 inlet storage tank, and heating of the compressor 11 inlet working fluid. This simplifies the use of the refrigeration system and improves its flexibility for independent use, allowing it to cope with more scenarios.

[0048] The following combination Figures 1 to 3 , the operation process of the refrigeration system is described through different embodiments to achieve carbon dioxide freezing capture, methane liquefaction and oxygen liquefaction.

[0049] Example 1: See Figure 1 and Figure 3 The average ambient temperature on Mars is 218K and it is driven by an oil-free compressor.

[0050] The mixed refrigerant is compressed into a high-pressure refrigerant of 1.8 MPa by the compressor 11, cooled to 238 K by the aftercooler 12, cooled to 150 K by the refluxed low-pressure refrigerant in the first regenerator 13, further cooled to 100 K by the low-pressure refrigerant in the second regenerator 13, and reduced to 0.4 MPa by the first throttle valve 14. The throttled refrigerant returns to the second regenerator 13 to cool the high-pressure refrigerant, methane and oxygen, and is reheated to about 140 K by the second regenerator 13 for condensing carbon dioxide in the Martian atmosphere. The low-pressure refrigerant is heated to about 147 K by the carbon dioxide capture module 15, and enters the gas-liquid separation tank 10 after further reheating by the first regenerator 13. Then the gas phase enters the compressor 11, and the cycle is repeated.

[0051] The methane and oxygen propellants generated by the chemical reaction are both assumed to be 0.5 MPa, and are cooled and liquefied in the regenerator 13, where the methane is cooled to 120K and the oxygen is cooled to 100K. They are then throttled to 0.12 MPa by the second throttle valve 23. The liquid methane is stored in the liquid methane storage tank 17, and the liquid oxygen is stored in the liquid oxygen storage tank 16. The gases are then exhausted for processing.

[0052] In the above embodiment, the molar fractions of the mixed refrigerant are: neon 2%, nitrogen 20%, methane 40%, ethylene 15%, ethane 10%, and propane 13%; the resulting COP (Coefficient of Performance) is 1.1 and the thermodynamic perfection is 26%.

[0053] Example 2: See Figure 2 and Figure 3The average ambient temperature on Mars is 218K and it is driven by an oil-free compressor.

[0054] The mixed refrigerant is compressed into a high-pressure refrigerant of 1.8 MPa by the compressor 11, cooled to 238K by the aftercooler 12, and then enters the regenerator 13. The refluxed low-temperature and low-pressure refrigerant is cooled to 100K, throttled to 0.4 MPa by the first throttle valve 14, and then enters the carbon dioxide capture module 15 to freeze the carbon dioxide in the Martian atmosphere. It is reheated to 97K and enters the regenerator 13 to cool the high-pressure refrigerant, oxygen and methane. After being reheated by the regenerator 13, it enters the gas-liquid separation tank 10, and then the gas phase enters the compressor 11, and the cycle is repeated.

[0055] The methane and oxygen propellants generated by the chemical reaction are both assumed to be 0.5 MPa. Both are cooled to 100K in the regenerator 13 and then throttled to 0.12 MPa by the second throttle valve 23. The liquid methane is stored in the liquid methane storage tank 17, and the liquid oxygen is stored in the liquid oxygen storage tank 16. The gases are then exhausted for processing.

[0056] In the above embodiment, the molar fractions of the mixed refrigerant are: neon 1%, nitrogen and methane 32% each, ethylene 15%, ethane 7%, and propane 13%; the resulting COP (Coefficient of Performance) is 0.86 and the thermodynamic perfection is 21%.

[0057] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A refrigeration system for the in-situ propellant storage process on Mars, characterized in that: include: A gas-liquid separation storage tank (10), a compressor (11), an aftercooler (12), a regenerator (13), and a first throttle valve (14) are connected in sequence, and further includes a carbon dioxide capture module (15), a liquid oxygen storage tank (16), a liquid methane storage tank (17), and a fan (18); The regenerator (13) includes a high-pressure refrigerant flow channel, a low-pressure refrigerant flow channel, an oxygen flow channel, and a methane flow channel. The gaseous oxygen is liquefied in the oxygen flow channel and then stored in the liquid oxygen storage tank (16). The gaseous methane is liquefied in the methane flow channel and then stored in the liquid methane storage tank (17). The carbon dioxide capture module (15) comprises a refrigerant flow channel and a carbon dioxide flow channel, the refrigerant in the refrigerant flow channel is used to provide cold for carbon dioxide freezing and capture, the fluid in the carbon dioxide flow channel is the Martian atmosphere, and the Martian atmosphere is introduced into the carbon dioxide capture module (15) through the fan (18); The outlet of the compressor (11) is connected to the inlet of the aftercooler (12), and the outlet of the aftercooler (12) is connected in sequence to the high-pressure refrigerant flow path of the regenerator (13) and the first throttle valve (14). The refrigerant after passing through the first throttle valve (14) enters the carbon dioxide capture module (15) or enters the low-pressure refrigerant flow path of the regenerator (13). The carbon dioxide capture module (15) is arranged on the low-pressure refrigerant side. The refrigerant outlet of the carbon dioxide capture module (15) is connected to the low-pressure refrigerant flow path inlet of the regenerator (13). The low-pressure refrigerant outlet of the regenerator (13) is connected to the gas-liquid separation storage tank (10). The gas phase separated by the gas-liquid separation storage tank (10) enters the compressor (11).

2. The refrigeration system for the in-situ propellant storage process on Mars according to claim 1, characterized in that: The regenerator (13) is provided with a carbon dioxide capture module (15) disposed between the first throttle valve (14) and the regenerator (13); Alternatively, a plurality of the regenerators (13) are provided, and the carbon dioxide capture module (15) is provided between any two regenerators (13).

3. The refrigeration system for the in-situ propellant storage process on Mars according to claim 1, characterized in that: The carbon dioxide capture module (15) comprises a plurality of submodules (151) connected in parallel, wherein a portion of the submodules (151) has a refrigeration working mode for freezing and capturing carbon dioxide, and another portion of the submodules (151) has a heating working mode for heating condensed pure carbon dioxide to sublimely increase its pressure, and the refrigeration working mode and the heating working mode are performed alternately.

4. The refrigeration system for the in-situ propellant storage process on Mars according to claim 3, characterized in that: The inlet end of each submodule (151) is connected to a first valve (152), and the outlet end is connected to a second valve (153). The first valve (152) is connected to the Martian atmosphere pipeline (19). In a cooling working mode, the first valve (152) and the second valve (153) are opened. In a heating working mode, the first valve (152) and the second valve (153) are closed.

5. The refrigeration system for the in-situ propellant storage process on Mars according to any one of claims 1 to 4, characterized in that: A supercharger is provided at the inlet end of the carbon dioxide capture module (15), and the Martian atmosphere enters the carbon dioxide capture module (15) after being pressurized by the supercharger.

6. The refrigeration system for the in-situ propellant storage process on Mars according to claim 5, characterized in that: The refrigeration system further comprises a cold recovery device (22) connected to the carbon dioxide capture module (15) for recovering the cold of the uncondensed gas.

7. The refrigeration system for the in-situ propellant storage process on Mars according to any one of claims 1 to 4, characterized in that: The refrigerant is a non-azeotropic mixed refrigerant, comprising: neon with a molar fraction of 0-15%; nitrogen with a molar fraction of 10%-30%; methane with a molar fraction of 20%-40%; ethane, ethylene, carbon tetrafluoride and their mixtures with a molar fraction of 10%-30%; propane, isobutane, isopentane and their mixtures with a molar fraction of 10%-30%.

8. The refrigeration system for the in-situ propellant storage process on Mars according to claim 7, characterized in that: The carbon dioxide capture temperature, methane liquefaction temperature and oxygen liquefaction temperature are all more than 5°C lower than the saturation temperature at the corresponding pressure.

9. The refrigeration system for the in-situ propellant storage process on Mars according to claim 1, characterized in that: The refrigeration system is used directly in the Martian atmosphere and is suitable for use in non-constant temperature environments.

10. The refrigeration system for the in-situ propellant storage process on Mars according to claim 1, characterized in that: When the refrigeration system is in operation, any one, two or three functions of carbon dioxide capture, methane liquefaction and oxygen liquefaction may be enabled.

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