A method of full subcooled liquid methane filling

Abstract

The application provides a full supercooled liquid methane filling method, which comprises the following steps: cold agent transfer filling: a cold agent tank truck fills cold agent into a cold agent filling module through a pipeline; cold agent filling: the cold agent filling module connects a liquid methane supercooling tank of a supercooled liquid methane module through a filling pipeline, and cold agent filling is performed; liquid methane transfer filling: a liquid methane tank truck fills liquid methane into the liquid methane supercooling tank of the supercooled liquid methane module through a pipeline; liquid methane supercooling: liquid methane in the liquid methane supercooling tank is cooled by heat exchange with the cold agent through a spaced metal wall; supercooled liquid methane filling: the supercooled liquid methane module is connected to a liquid methane filling module through a pipeline, and the liquid methane supercooling tank is pressurized to fill the liquid methane cooled in the liquid methane supercooling tank into a rocket tank; the liquid methane supercooling tank comprises a liquid methane tank and a heat preservation layer outside the liquid methane tank, and a cold agent interlayer is arranged between the liquid methane tank and the heat preservation layer to accommodate the cold agent provided by the cold agent filling module and cool the liquid methane in the liquid methane tank. The filling system can improve the liquid methane supercooling efficiency, does not cause liquid methane crystallization, and is stable and efficient in the supercooling process and has high economic benefits in the supercooled filling process.

Description

Technical Field

[0001] This invention relates to the field of cryogenic liquid rocket refueling technology, and more particularly to liquid methane refueling, specifically a method for refueling fully subcooled liquid methane. Background Technology

[0002] With the rapid development of the aerospace industry, various technologies involved in the rocket field have also made leaps and bounds. In particular, with the development of cryogenic launch vehicle technology, the novel propellant combination of liquid oxygen and liquid methane has attracted widespread attention and is increasingly being used in practice. Currently, liquid methane subcooling technology generally relies on supercooler heat exchange, meaning that liquid methane is subcooled and added simultaneously on the day of refueling. This requires high control during refueling, and excessively low liquid methane temperatures pose a risk of crystallization, which can easily clog the supercooler and seriously affect the launch mission.

[0003] When using a supercooler to subcool liquid methane, in emergency situations or when refueling needs to be stopped after completion, the liquid methane cannot be stopped immediately to prevent crystallization. The flow must wait until liquid nitrogen has drained to a safe level before stopping, resulting in waste. With the development of cryogenic rocket and aerospace technology, there is an urgent need for a liquid methane subcooling refueling system and method that can meet the requirements of high frequency, full subcooling, large subcooling capacity, safety, stability, and economy. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a fully subcooled liquid methane refueling method to solve the problems of low subcooling efficiency, easy crystallization, unstable subcooling process and easy waste of resources in the prior art.

[0005] This invention provides a method for refueling fully subcooled liquid methane, the method comprising: refrigerant transfer: a refrigerant tanker transfers refrigerant into the refrigerant storage tank of a refrigerant refueling module via pipeline;

[0006] Refrigerant charging: The refrigerant charging module is connected to the liquid methane subcooled storage tank of the subcooled liquid methane module through a charging pipeline, and refrigerant is charged.

[0007] Liquid methane transfer: Liquid methane tank trucks transfer liquid methane through pipelines to the liquid methane subcooled storage tank of the subcooled liquid methane module;

[0008] Liquid methane subcooling: The liquid methane in the liquid methane subcooling tank exchanges heat with the refrigerant through the spaced metal walls to lower the temperature;

[0009] Subcooled liquid methane refueling: The subcooled liquid methane module pipeline is connected to the liquid methane refueling module, and the cooled liquid methane is refueled into the rocket tank by pressurizing the liquid methane subcooled storage tank.

[0010] The liquid methane subcooled storage tank includes a liquid methane storage tank and an insulation layer located outside the liquid methane storage tank. A refrigerant interlayer is provided between the liquid methane storage tank and the insulation layer to accommodate the refrigerant provided by the refrigerant filling module and to cool the liquid methane in the liquid methane storage tank.

[0011] Further, refrigerant filling: Before the refrigerant filling module is connected to the liquid methane subcooled storage tank of the subcooled liquid methane module through a filling pipeline and the refrigerant filling step is performed, the filling method includes: refrigerant temperature control: controlling the pressure inside the refrigerant storage tank by controlling the self-pressurizing pipeline connected to the refrigerant storage tank, thereby changing the temperature of the refrigerant.

[0012] Further, supercooled liquid methane refueling: The supercooled liquid methane module pipeline is connected to the liquid methane refueling module. Before the step of refueling the rocket tank with cooled liquid methane, the refueling method includes: supercooled liquid methane self-circulation: Controlling the activation of the circulation pump to circulate the refrigerant added to the supercooled liquid methane storage tank.

[0013] Furthermore, the supercooled liquid methane refueling: the supercooled liquid methane module pipeline is connected to the liquid methane refueling module. After the step of refueling the rocket tank with cooled liquid methane, the refueling method includes: helium recovery: after refueling, the helium in the liquid methane tank can be recovered back into the high-pressure helium cylinder group by turning on the high-pressure booster pump, thus completing helium recovery and reducing refueling costs.

[0014] Furthermore, the refrigerant refueling module includes: a refrigerant storage tank, which is connected to the liquid methane subcooled storage tank via a refrigerant refueling pipeline to provide refrigerant for the liquid methane; the refrigerant refueling pipeline is connected to a refrigerant tanker for providing refrigerant via a refrigerant transfer pipeline; the top and bottom of the refrigerant storage tank are connected via a self-pressurizing pipeline for adjusting the pressure of the refrigerant storage tank by refrigerant vaporization, thereby adjusting the refrigerant temperature; the top of the refrigerant storage tank is connected to the top of the refrigerant jacket via a refrigerant pressurizing pipeline for pressurizing the refrigerant jacket; and a refrigerant storage tank exhaust pipe is provided at the top of the refrigerant storage tank for regulating the pressure of the refrigerant storage tank.

[0015] Furthermore, the self-pressurizing pipeline is sequentially equipped with a self-pressurizing shut-off valve, a self-pressurizing regulating valve, and a self-pressurizing vaporizer; the upstream of the refrigerant tank exhaust pipe is connected to the top gas phase space of the refrigerant tank through two parallel pipes, and the downstream of the refrigerant tank exhaust pipe is merged into one pipe and connected to the atmosphere; on the parallel pipes upstream of the refrigerant tank exhaust pipe, one pipe is equipped with a safety vent valve, and the other pipe is equipped with a refrigerant tank exhaust valve.

[0016] In a specific embodiment of the present invention, the supercooled liquid methane module includes a supercooled liquid methane storage tank. The liquid methane storage tank has a lower inlet pipe at the bottom and an upper outlet pipe at the top. The lower inlet pipe is connected to a liquid methane tank truck via a liquid methane transfer pipeline to provide liquid methane. The upper outlet pipe is connected to the lower inlet pipe via a supercooled liquid methane filling pipeline. The upstream end of the supercooled liquid methane filling pipeline is connected to the liquid methane storage tank via the lower inlet pipe, and the downstream end is connected to the rocket storage tank. A high-pressure helium cylinder group is connected to the upper part of the liquid methane storage tank via a helium gas replenishment pipe to provide high-pressure gas to the liquid methane storage tank.

[0017] Furthermore, the liquid methane storage tank is equipped with a lower liquid methane chamber thermometer and an upper liquid methane chamber thermometer, which are used to measure the temperature of the liquid methane in the lower and upper parts of the liquid methane storage tank, respectively; a cryogenic circulation pump is installed on the subcooled liquid methane filling pipeline between the lower inlet pipe and the upper outlet pipe, which is used to circulate and mix the liquid methane in the upper and lower parts of the liquid methane storage tank to maintain a uniform temperature of the liquid methane in the liquid methane storage tank.

[0018] Furthermore, the liquid methane storage tank is connected to a methane chamber pressure gauge in the top gas phase space, and the top of the liquid methane storage tank is connected to the atmosphere through a liquid methane storage tank exhaust pipe for pressure relief; the refrigerant jacket is connected to a jacket chamber pressure gauge in the top gas phase space, and the top of the refrigerant jacket is connected to the atmosphere through a jacket chamber exhaust pipe for pressure relief.

[0019] Furthermore, the liquid methane refueling module includes a supercooled liquid methane refueling pipeline connecting the supercooled liquid methane module and the rocket tank. The supercooled liquid methane refueling pipeline is equipped with a supercooled liquid methane refueling shut-off valve, a flow meter for measuring the liquid methane flow rate, and a supercooled liquid methane refueling regulating valve for adjusting the liquid methane flow rate.

[0020] As can be seen from the above embodiments, the fully subcooled liquid methane refueling method provided by the present invention has at least one of the following advantages:

[0021] 1. The technology provided by this invention can realize the storage of subcooled and supercooled liquid methane in a jacketed storage tank. The temperature of the refrigerant is controllable and will not be lower than the freezing point of liquid methane, so it will not cause liquid methane crystallization. This avoids the risk of ice blockage that may occur when using a supercooler for supercooling on the day of refueling, which may affect the rocket launch.

[0022] 2. The supercooling system of this application can produce a large amount of supercooled liquid methane. The supercooling flow rate is not limited by the heat exchanger's heat exchange capacity, and it can provide a larger flow rate of liquid methane refueling. It has the capability to provide large-volume and large-flow supercooling refueling for medium and large cryogenic liquid rockets.

[0023] 3. In addition, by using the subcooling system of this application, online subcooling is not required on the day of refueling, which can achieve large-flow refueling, is not limited by the capacity of the heat exchanger, and greatly reduces the refueling time.

[0024] 4. The method provided by the present invention involves adding refrigerant first and then adding liquid methane. Adding refrigerant first can reduce the temperature of the jacket and inner cylinder of the liquid methane storage tank, thus playing a pre-cooling role. Moreover, the refrigerant used is economical and has a lower cost.

[0025] 5. The filling method provided by this invention can stop the flow of subcooled liquid methane at any time without worrying about ice blockage in the subcooler, and the response speed is faster in emergency situations.

[0026] 6. The triple point temperature of liquid argon (83.81 K) is 6.85 K lower than that of liquid methane (90.66 K). Liquid nitrogen (63.15 K) is 27.51 K lower than that of liquid methane (90.66 K). The temperature difference between the refrigerant used in this application and the triple point temperature of liquid methane is small, thus reducing the risk of liquid methane crystallization. The temperature of the refrigerant used in this application is also more easily controlled above the liquid methane crystallization temperature through pressure increase. Furthermore, liquid argon is commercially available and is a common, low-cost refrigerant.

[0027] 7. The helium used for pressurization and boosting of the inner cylinder of the liquid methane storage tank in this application has extremely low solubility in liquid methane and will not contaminate the liquid methane. Moreover, helium is an inert gas, making it safer. Given the high price of helium, this application also includes a helium recovery device to reduce costs. By using a booster pump to recompress the helium back into a high-pressure helium cylinder, the helium can be reused, significantly reducing launch costs.

[0028] It should be understood that the above general description and the following specific embodiments are merely exemplary and illustrative, and do not limit the scope of the invention. Attached Figure Description

[0029] The accompanying drawings, which are part of the specification of this invention, illustrate exemplary embodiments of the invention. The drawings, together with the description in the specification, serve to illustrate the principles of the invention.

[0030] Figure 1 This is a schematic diagram of the filling system for a fully subcooled liquid methane filling method provided by the present invention.

[0031] Explanation of reference numerals in the attached figures:

[0032] 1-Refrigerant storage tank, 2-Self-pressurizing shut-off valve, 3-Self-pressurizing regulating valve, 4-Self-pressurizing vaporizer, 5-First refrigerant thermometer, 6-Refrigerant filling shut-off valve, 7-Refrigerant pipeline filter, 8-Refrigerant filling regulating valve, 9-Second refrigerant thermometer, 10-Refrigerant tank truck, 11-Refrigerant transfer shut-off valve;

[0033] 12-Liquid methane tanker, 13-Liquid methane transfer shut-off valve, 14-Cryogenic circulating pump, 15-Subcooled liquid methane refueling shut-off valve, 16-Flow meter, 17-Subcooled liquid methane refueling regulating valve, 18-Liquid methane inlet temperature sensor, 19-Subcooled liquid methane refueling valve, 20-Rocket storage tank;

[0034] 21-Liquid methane lower chamber thermometer, 22-Liquid methane upper chamber thermometer, 23-High pressure booster pump, 24-High pressure helium cylinder group, 25-High pressure helium pressure reducing valve, 26-Methane chamber pressure gauge;

[0035] 27-Gas emission regulating valve, 28-Argon air temperature regulator, 29-Jack cavity exhaust pipe, 30-Jack cavity pressure gauge, 31-Jack cavity pressure replenishment regulating valve, 32-Upper jacket cavity level gauge, 33-Lower jacket cavity level gauge, 34-Pressure replenishment shut-off valve, 35-Safety vent valve, 36-Refrigerant tank exhaust pipe, 37-Refrigerant tank pressure gauge, 38-Third refrigerant temperature sensor;

[0036] 39 - Liquid methane storage tank; 40 - Insulation layer;

[0037] 41-Refrigerant transfer line, 42-Refrigerant charging line, 43-Liquid methane transfer line, 44-Subcooled liquid methane charging line, 45-Refrigerant pressurization line;

[0038] 46-Pressure regulating valve, 47-Liquid methane circulation shut-off valve, 48-Refrigerant storage tank exhaust valve, 49-Liquid methane storage tank exhaust valve;

[0039] 50 - Self-pressurization pipeline, 51 - Liquid methane storage tank exhaust pipe, 52 - Lower liquid inlet pipe, 53 - Upper liquid outlet pipe, 54 - Refrigerant jacket. Detailed Implementation

[0040] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0041] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be obvious to those skilled in the art. This application specification and embodiments are merely exemplary.

[0042] This invention provides a method for injecting fully subcooled liquid methane, such as... Figure 1The diagram shows the structure of the refueling system used in this liquid methane refueling method. In a specific embodiment, the refueling system includes: a refrigerant refueling module, a subcooled liquid methane module, and a liquid methane refueling module. The refrigerant refueling module is connected to the subcooled liquid methane storage tank of the subcooled liquid methane module via a refueling pipeline, and is used to subcool the liquid methane in the storage tank.

[0043] The subcooled liquid methane module pipeline is connected to the liquid methane refueling module and is used to refuel the rocket tank 20 with cooled liquid methane.

[0044] Furthermore, the liquid methane subcooled storage tank includes a liquid methane storage tank 39 and an insulation layer 40 located outside the liquid methane storage tank 39. A refrigerant jacket 54 is provided between the liquid methane storage tank 39 and the insulation layer 40 to contain the refrigerant provided by the refrigerant filling module for cooling the liquid methane in the liquid methane storage tank 39.

[0045] In a specific embodiment of the present invention, the refrigerant filling module includes: a refrigerant storage tank 1, which is connected to a liquid methane subcooled storage tank via a refrigerant filling pipeline 42 to provide refrigerant for the liquid methane.

[0046] The refrigerant filling line 42 is connected to the refrigerant tanker 10 via the refrigerant transfer line 41. The refrigerant transfer line 41 is equipped with a refrigerant transfer shut-off valve 11 to control the opening and closing of the refrigerant transfer. Additionally, the refrigerant filling line 42 between the refrigerant transfer line 41 and the refrigerant storage tank 1 is sequentially equipped with a refrigerant line filter 7 for filtering the refrigerant, a refrigerant filling shut-off valve 6 for controlling refrigerant filling and transfer, and a first refrigerant thermometer 5 for measuring the refrigerant temperature.

[0047] The refrigerant filling pipeline 42 between the refrigerant transfer pipeline 41 and the liquid methane subcooled storage tank is sequentially equipped with a refrigerant filling regulating valve 8 for controlling refrigerant filling and a second refrigerant thermometer 9 for measuring refrigerant temperature.

[0048] The top and bottom of refrigerant storage tank 1 are connected by a self-pressurizing pipeline 50, which is used to adjust the pressure of refrigerant storage tank 1 by refrigerant vaporization, thereby adjusting the refrigerant temperature and increasing the pressure for refrigerant discharge, which is more conducive to supplying refrigerant to the subcooled liquid methane module. The self-pressurizing pipeline 50 is connected upstream to the bottom of refrigerant storage tank 1 and downstream to the top of refrigerant storage tank 1. The upstream part of the self-pressurizing pipeline 50 is sequentially equipped with a self-pressurizing shut-off valve 2, a self-pressurizing regulating valve 3, and a self-pressurizing vaporizer 4, which are used to realize refrigerant vaporization and replenish the upper gas phase space of refrigerant storage tank 1 through the pipeline, increasing the gas pressure inside refrigerant storage tank 1 and thus changing the refrigerant temperature. In addition, by increasing the gas pressure inside refrigerant storage tank 1, it is also beneficial to transport refrigerant to the subcooled liquid methane module, thereby achieving the subcooling effect.

[0049] Additionally, the top of the refrigerant storage tank 1 is connected to the top of the refrigerant jacket 54 via a refrigerant pressurization pipeline 45 for pressurizing the refrigerant jacket 54. The refrigerant pressurization pipeline 45 is connected upstream to the refrigerant storage tank 1 and downstream to the vapor space at the top of the refrigerant jacket 54. A pressure-replenishing shut-off valve 34 and a jacket cavity pressure-replenishing regulating valve 31 are sequentially installed on the refrigerant pressurization pipeline 45 from upstream to downstream. Furthermore, a jacket cavity pressure gauge 30 is connected to the vapor space at the top of the refrigerant jacket 54 for real-time pressure monitoring, thereby dynamically adjusting the internal pressure of the refrigerant jacket 54 by controlling the jacket cavity pressure-replenishing regulating valve 31.

[0050] The top of the refrigerant storage tank 1 is equipped with a refrigerant storage tank vent pipe 36, which is used to regulate the pressure of the refrigerant storage tank 1. Specifically, the upstream of the refrigerant storage tank vent pipe 36 is connected to the gas phase space at the top of the refrigerant storage tank 1 through two parallel pipes, and the downstream of the refrigerant storage tank vent pipe 36 is merged into one pipe and connected to the atmosphere.

[0051] On the parallel pipes upstream of the refrigerant storage tank vent pipe 36, one pipe is equipped with a safety vent valve 35, and the other pipe is equipped with a refrigerant storage tank vent valve 48.

[0052] In addition, a refrigerant tank pressure gauge 37 is installed on the top of the refrigerant tank 1 to detect the air pressure inside the refrigerant tank 1 in real time, and to adjust the internal pressure of the refrigerant tank 1 through the safety vent valve 35 on the refrigerant tank exhaust pipe 36 and the refrigerant tank exhaust valve 48.

[0053] In addition, a third refrigerant thermometer 38 is installed on the refrigerant storage tank 1 to detect the temperature of the refrigerant inside the refrigerant storage tank 1 in real time, and to adjust the temperature by adjusting the state of the self-pressurization structure.

[0054] In a specific embodiment of the present invention, the subcooled liquid methane module includes a liquid methane subcooled storage tank. The liquid methane storage tank 39 within the subcooled storage tank has a lower inlet pipe 52 at its bottom and an upper outlet pipe 53 at its top. The lower inlet pipe 52 is connected to the liquid methane tank truck 12 via a liquid methane transfer pipeline 43 for supplying liquid methane. A liquid methane transfer shut-off valve 13 is installed on the liquid methane transfer pipeline 43 for controlling the transfer of liquid methane.

[0055] The upper liquid outlet pipe 53 and the lower liquid inlet pipe 52 are connected through the supercooled liquid methane refueling pipeline 44. The upstream of the supercooled liquid methane refueling pipeline 44 is connected to the liquid methane storage tank 39 through the lower liquid inlet pipe 52, and the downstream is connected to the rocket storage tank 20, which is used to provide supercooled liquid methane to the rocket storage tank 20.

[0056] The upper part of the liquid methane storage tank 39 is connected to a high-pressure helium cylinder group 24 via a helium gas replenishment pipe. This group provides high-pressure gas to the liquid methane storage tank 39, increasing the internal pressure and facilitating the injection of subcooled liquid methane into the rocket propellant tank 20. A methane chamber pressure gauge 26 is connected to the upper gas phase space of the liquid methane storage tank 39 to monitor the internal pressure in real time. The helium gas replenishment pipe connecting the high-pressure helium cylinder group 24 to the liquid methane storage tank 39 is equipped with a high-pressure helium pressure reducing valve 25 and a pressure regulating valve 46, which dynamically adjust the pressurization of the liquid methane storage tank 39 based on the pressure value detected by the methane chamber pressure gauge 26.

[0057] In addition, a helium recovery pipeline is provided between the high-pressure helium cylinder group 24 and the liquid methane storage tank 39. A high-pressure booster pump 23 is installed on the helium recovery pipeline to recover the helium in the gas phase space inside the liquid methane storage tank 39 back to the high-pressure helium cylinder group 24. Preferably, the booster helium can also be any gas that is insoluble in liquid methane, inert, highly safe, and economical.

[0058] Furthermore, the liquid methane storage tank 39 is equipped with a liquid methane lower chamber temperature sensor 21 and a liquid methane upper chamber temperature sensor 22, which are used to measure the liquid methane temperature in the lower and upper parts of the liquid methane storage tank 39, respectively.

[0059] In addition, a cryogenic circulation pump 14 is installed on the subcooled liquid methane filling pipeline 44 between the lower inlet pipe 52 and the upper outlet pipe 53. This pump is used to circulate and mix the liquid methane in the upper and lower parts of the liquid methane storage tank 39, maintaining a uniform temperature of the liquid methane within the tank. Because there will be a temperature difference between the upper and lower parts of the liquid methane in the liquid methane storage tank 39 during the preparation process or after long-term storage, it is necessary to thoroughly mix the liquid methane in the tank 39 to ensure that the internal liquid methane temperatures are similar or have no temperature difference.

[0060] In a specific embodiment of the present invention, the top of the liquid methane storage tank 39 is connected to the atmosphere through a liquid methane storage tank vent pipe 51 for depressurization. A liquid methane storage tank vent valve 49 is provided on the liquid methane storage tank vent pipe 51 to control the venting of the liquid methane storage tank 39 into the atmosphere, facilitating the transfer and filling of liquid methane.

[0061] In addition, the top of the refrigerant jacket 54 is connected to the atmosphere through the jacket cavity vent pipe 29 for depressurization, which is used for refrigerant charging and depressurization. The jacket cavity vent pipe 29 is equipped with a gas discharge regulating valve 27 and an argon gas temperature regulator 28.

[0062] In embodiments of the present invention, there are two methods for transferring liquid methane. One method is as follows: open the liquid methane transfer shut-off valve 13, open the liquid methane storage tank exhaust valve 49, and then increase the pressure inside the liquid methane tank truck 12 through the liquid methane booster vaporizer. The liquid methane is then transported to the liquid methane storage tank 39 through the lower inlet pipe 52 using the pressure difference.

[0063] Another transfer method is to open the liquid methane transfer shut-off valve 13 and the liquid methane circulation shut-off valve 47, and start the cryogenic circulation pump 14 to transfer the liquid methane in the liquid methane tanker 12 to the liquid methane storage tank 39 through the upper outlet pipe 53.

[0064] In a specific embodiment of the present invention, an upper chamber level gauge 32 is provided on the upper part of the insulation layer 40, and a lower chamber level gauge 33 is provided on the lower part of the insulation layer 40. Both the upper chamber level gauge 32 and the lower chamber level gauge 33 are connected to the refrigerant jacket 54 and are used to measure the refrigerant level. When the refrigerant level is detected to be lower than the lower chamber level gauge 33, the refrigerant storage tank 1 is controlled to add refrigerant into the refrigerant jacket 54. When the refrigerant level is detected to reach or exceed the upper chamber level gauge 32, the refrigerant storage tank 1 is controlled to stop adding refrigerant into the refrigerant jacket 54.

[0065] In a specific embodiment of the present invention, the liquid methane refueling module includes a supercooled liquid methane refueling pipeline 44 connecting the supercooled liquid methane module and the rocket tank 20. The supercooled liquid methane refueling pipeline 44 is equipped with a supercooled liquid methane refueling shut-off valve 15, a flow meter 16 for measuring the flow rate of liquid methane, and a supercooled liquid methane refueling regulating valve 17 for adjusting the flow rate of liquid methane.

[0066] Furthermore, a liquid methane inlet thermometer 18 and a liquid methane inlet valve 19 are installed at one end of the supercooled liquid methane refueling pipeline 44 near the rocket tank 20.

[0067] In the embodiments of the present invention, there are two methods for the refueling process of liquid methane. One refueling method is as follows: open the supercooled liquid methane refueling cut-off valve 15, close the liquid methane transfer cut-off valve 13, open the supercooled liquid methane refueling valve 19, pressurize the liquid methane storage tank 39 through the high-pressure helium cylinder group 24, and use the pressure difference to squeeze the supercooled liquid methane into the rocket storage tank 20.

[0068] Another method of refueling is as follows: open the supercooled liquid methane refueling cut-off valve 15, close the liquid methane transfer cut-off valve 13, open the supercooled liquid methane refueling valve 19, and then start the cryogenic circulation pump 14 to pump the supercooled liquid methane into the rocket tank 20.

[0069] In a specific embodiment of the present invention, the refrigerant is liquid argon. Liquid argon can be replaced with liquid nitrogen or other inert cryogenic media with a boiling point lower than that of liquid methane and higher than that of liquid methane, but the refrigerant storage temperature needs to be adjusted accordingly. If liquid nitrogen is used instead, the refrigerant tank pressure and the tank jacket pressure need to be increased by approximately 2.5 times compared to liquid argon.

[0070] This invention provides a method for injecting fully subcooled liquid methane, the specific steps of which include:

[0071] Step S1: Refrigerant Transfer: The refrigerant tanker transfers refrigerant to the refrigerant storage tank of the refrigerant filling module via pipeline. Specifically, the refrigerant tanker 10 is connected to the refrigerant transfer pipeline 41. The tanker pressure is increased by the self-pressurizing vaporizer of the refrigerant tanker 10. The refrigerant transfer shut-off valve 11 is opened, the refrigerant filling regulating valve 8 is closed, the refrigerant filling shut-off valve 6 is opened, and the refrigerant tank vent valve 48 is opened. The refrigerant is transferred to the refrigerant storage tank 1 through the pressure difference.

[0072] Step S2: Refrigerant Temperature Control: The pressure inside the refrigerant tank is controlled by regulating the self-pressurizing pipeline connected to the refrigerant tank, thereby changing the refrigerant temperature. Specifically, since the triple point temperature of liquid argon (83.81K) is 6.85K lower than that of liquid methane (90.66K), the liquid argon needs to be heated. The heating method is to increase the pressure in the liquid argon tank; the increased pressure corresponds to an increase in the saturation temperature. The self-pressurizing shut-off valve 2 is opened, and the opening of the self-pressurizing regulating valve 3 is controlled. Liquid argon flows from the refrigerant tank 1 into the self-pressurizing vaporizer 4, increasing its volume by approximately 780 times. After vaporization, the argon gas returns to the gas phase space above the refrigerant tank 1. With the increased gas volume in the confined space, the internal pressure of the refrigerant tank 1 rises. The self-pressurizing regulating valve 3 is interlocked with the refrigerant tank pressure gauge 37 to control the opening, maintaining the pressure of refrigerant tank 1 at about 0.15MPa (absolute pressure). The liquid argon temperature will gradually rise until it reaches the corresponding saturation temperature of about 91K at 0.15MPa, and then reach a dynamic equilibrium state, thus completing the refrigerant temperature control.

[0073] Step S3: Refrigerant Refilling: The refrigerant refilling module is connected to the liquid methane subcooled storage tank of the subcooled liquid methane module via a refilling pipeline, and refrigerant is refilled. Specifically, the refrigerant transfer shut-off valve 11 is closed, and the refrigerant refill shut-off valve 6 is opened to introduce liquid argon into the refrigerant jacket 54 of the liquid methane subcooled storage tank. When the pressure in the refrigerant jacket 54 is greater than 0.15 MPa (absolute pressure), the gas discharge regulating valve 27 interlocks with the jacket chamber pressure gauge 30 and opens to release pressure. When the pressure is lower than 0.1 MPa (absolute pressure), the opening of the gas discharge regulating valve 27 is reduced or closed to maintain the pressure in the refrigerant jacket 54 at 0.15 MPa (absolute pressure).

[0074] When the liquid argon level in the refrigerant jacket 54 is lower than the level mark of the lower chamber level gauge 33, increase the opening of the refrigerant filling regulating valve 8. When the liquid argon level is higher than the level mark of the upper chamber level gauge 32, decrease or close the opening of the refrigerant filling regulating valve 8 to complete the refrigerant filling.

[0075] When the pressure in the refrigerant jacket 54 is lower than 0.15 MPa (absolute pressure), the pressure adjustment valve 31 of the interlocked jacket chamber pressure gauge 30 can be adjusted to replenish the pressure in the refrigerant jacket 54, maintain the pressure inside the jacket, and thus maintain the saturation temperature of liquid argon in the refrigerant jacket 54 from dropping.

[0076] Step S4: Liquid Methane Transfer: The liquid methane tanker transfers liquid methane to the subcooled liquid methane storage tank of the subcooled liquid methane module via pipeline. Specifically, the liquid methane tanker 12 is connected to the third liquid methane transfer pipeline 43, the subcooled liquid methane filling shut-off valve 15 is closed, and the liquid methane transfer shut-off valve 13 is opened. The pressure inside the liquid methane tanker 12 is increased by the liquid methane booster vaporizer. Then, the liquid methane storage tank vent valve 49 is opened, and the liquid methane is transferred to the liquid methane storage tank 39 by pressure difference. Alternatively, the liquid methane circulation shut-off valve 47 can be opened, and the liquid methane can be transferred to the liquid methane storage tank 39 using the cryogenic circulation pump 14.

[0077] Step S5: Liquid Methane Subcooling: The liquid methane and refrigerant in the liquid methane subcooling tank exchange heat and cool down through the spaced metal walls. Specifically, liquid methane and liquid argon exchange heat through the metal walls of the liquid methane storage tank 39. Because the refrigerant temperature is controlled above the freezing point of liquid methane, the two media can exchange heat for a long time. After the liquid argon absorbs the heat energy from the liquid methane, the temperature of the liquid methane decreases, resulting in a reduction in the volume and an increase in the density of the liquid methane. This increases the gas phase space in the liquid methane storage tank 39. To avoid negative pressure inside the liquid methane storage tank 39, the pressure gauge 26 in the methane chamber measures the pressure of the liquid methane storage tank 39 and interlocks to open the pressure adjustment valve 46, pressurizing the inner cylinder of the liquid methane storage tank 39 to atmospheric pressure. Since helium and liquid methane have extremely low solubility, the quality of the liquid methane propellant can be ensured not to be affected. After cooling, the temperature of the liquid methane is slightly higher than or equal to the temperature of the liquid argon refrigerant (91K), completing the liquid methane subcooling process.

[0078] Step S6: Subcooled Liquid Methane Self-Circulation: The circulation pump is activated to circulate the refrigerant added to the subcooled liquid methane storage tank. Specifically, during the preparation of subcooled liquid methane or during long-term storage, the temperature of the liquid methane in the liquid methane storage tank 39 may become uneven. If the temperature data measured by the lower chamber thermometer 21 and the upper chamber thermometer 22 differ significantly, it indicates that the temperature of the subcooled liquid methane in the storage tank is uneven. Then, the liquid methane circulation shut-off valve 47 is opened, and the cryogenic circulation pump 14 is automatically started to thoroughly mix the unevenly shaped subcooled liquid methane until the temperature deviation decreases or becomes uniform. The cryogenic circulation pump 14 then automatically stops.

[0079] Step S7: Subcooled Liquid Methane Refilling: The subcooled liquid methane module pipeline is connected to the liquid methane refilling module. Cooled liquid methane is added to the rocket propellant tank 20 by pressurizing the subcooled liquid methane storage tank. Specifically, the liquid methane transfer shut-off valve 13 is closed, the subcooled liquid methane refill shut-off valve 15 is opened, and the subcooled liquid methane refilling valve 19 is opened. The liquid methane storage tank 39 is pressurized through the high-pressure helium cylinder group 24, and the subcooled liquid methane is forced into the rocket propellant tank 20 using the pressure difference.

[0080] Another refueling method involves opening the supercooled liquid methane refueling cut-off valve 15, closing the liquid methane transfer cut-off valve 13, opening the supercooled liquid methane refueling valve 19, and then starting the cryogenic circulation pump 14 to pump the supercooled liquid methane into the rocket tank 20. The supercooled liquid methane refueling regulating valve 17 is interlocked with the flow meter 16 to control the refueling flow rate to meet the technical requirements for rocket launch. The liquid methane inlet temperature sensor 18 monitors in real time whether the supercooled liquid methane temperature meets the rocket inlet temperature requirements; if it does not meet the requirements, the inlet process is stopped.

[0081] Step S8: Helium recovery: After the refueling task is completed, the helium in the liquid methane storage tank 39 can be recovered back into the high-pressure helium cylinder group 24 by turning on the high-pressure booster pump 23, thus completing the helium recovery and reducing the refueling cost.

[0082] The above description is merely an illustrative embodiment of the present invention. Any equivalent changes and modifications made by those skilled in the art without departing from the concept and principles of the present invention shall fall within the scope of protection of the present invention.

Claims

1. A method of full subcooling liquid methane refueling, characterized in that, The filling method comprises: Cold agent transfer filling: the cold agent tank truck transfers cold agent to the cold agent filling module through the pipeline; Cold agent filling: the cold agent filling module connects the liquid methane supercooling tank of the supercooling liquid methane module through the filling pipeline, and performs cold agent filling; Liquid methane transfer filling: the liquid methane tank truck transfers liquid methane to the liquid methane supercooling tank of the supercooling liquid methane module through the pipeline; Liquid methane supercooling: the liquid methane in the liquid methane supercooling tank exchanges heat with the cold agent through the spaced metal wall to reduce the temperature; Supercooling liquid methane filling: the supercooling liquid methane module pipeline connects the liquid methane filling module, and the liquid methane supercooling tank is pressurized to fill the rocket tank (20) with the liquid methane after temperature reduction; The liquid methane supercooling tank comprises a liquid methane tank (39) and a heat preservation layer (40) outside the liquid methane tank (39), and a cold agent interlayer (54) is arranged between the liquid methane tank (39) and the heat preservation layer (40) to accommodate the cold agent provided by the cold agent filling module to reduce the temperature of the liquid methane in the liquid methane tank (39); The cold agent filling module comprises a cold agent tank (1), and the top of the cold agent tank (1) is connected to the top of the cold agent interlayer (54) through a cold agent pressurization pipeline (45) to pressurize the cold agent interlayer (54); The top of the cold agent interlayer (54) is connected with an interlayer cavity pressure gauge (30), and the top of the cold agent interlayer (54) is connected to the atmosphere through an interlayer cavity exhaust pipe (29) to release pressure.

2. The full subcooling liquid methane refueling method of claim 1, wherein, Before the step of cold agent filling: the cold agent filling module connects the liquid methane supercooling tank of the supercooling liquid methane module through the filling pipeline, and performs cold agent filling, the filling method comprises: Cold agent temperature control: the pressure in the cold agent tank is controlled by controlling the self-pressurization pipeline connected to the cold agent tank, so as to change the temperature of the cold agent.

3. The full subcooling liquid methane refueling method of claim 1, wherein, Before the step of supercooling liquid methane filling: the supercooling liquid methane module pipeline connects the liquid methane filling module to fill the rocket tank (20) with the liquid methane after temperature reduction, the filling method comprises: Supercooling liquid methane self-circulation: the circulation pump is controlled to be opened to circulate the cold agent filled into the liquid methane supercooling tank.

4. The full subcool liquid methane dispensing method of claim 1, wherein, After the step of supercooling liquid methane filling: the supercooling liquid methane module pipeline connects the liquid methane filling module to fill the rocket tank (20) with the liquid methane after temperature reduction, the filling method comprises: Helium recovery: after filling is completed, the helium in the liquid methane tank (39) can be recovered into the high-pressure helium bottle group (24) by opening the high-pressure pressurization pump (23), to complete helium recovery and reduce filling cost.

5. The full subcool liquid methane filling method according to any one of claims 1-4, characterized in that, The cold agent tank (1) is connected to the liquid methane supercooling tank through a cold agent filling pipeline (42) to provide cold agent for the liquid methane; The cold agent filling pipeline (42) is connected to the cold agent tank truck (10) for providing cold agent through a cold agent transfer filling pipeline (41); The top and the bottom of the cold agent tank (1) are connected through a self-pressurization pipeline (50) to adjust the pressure of the cold agent tank (1) by cold agent gasification, so as to adjust the temperature of the cold agent. The refrigerant tank (1) is provided with a refrigerant tank exhaust pipe (36) at the top, which is used to adjust the pressure of the refrigerant tank (1).

6. The full subcool liquid methane dispensing method of claim 5, wherein, The self-boosting pipeline (50) is sequentially provided with a self-boosting stop valve (2), a self-boosting regulating valve (3) and a self-boosting vaporizer (4). The refrigerant tank exhaust pipe (36) is communicated with the top gas phase space of the refrigerant tank (1) through two parallel pipelines upstream, and is combined into one pipeline downstream and communicated with the atmosphere. One of the parallel pipelines upstream of the refrigerant tank exhaust pipe (36) is provided with a safety relief valve (35), and the other pipeline is provided with a refrigerant tank exhaust valve (48).

7. The full subcool liquid methane fuelling method of any of claims 1-4, wherein, The supercooled liquid methane module includes the liquid methane supercooling tank, and the bottom of the liquid methane tank (39) in the liquid methane supercooling tank is provided with a lower liquid inlet pipe (52), and the upper part is provided with an upper liquid outlet pipe (53). The lower liquid inlet pipe (52) is communicated with the liquid methane tank truck (12) through a liquid methane transfer pipeline (43) to provide liquid methane. The upper liquid outlet pipe (53) is communicated with the lower liquid inlet pipe (52) through a supercooled liquid methane filling pipeline (44), and the supercooled liquid methane filling pipeline (44) is communicated with the liquid methane tank (39) through the lower liquid inlet pipe (52) upstream, and is communicated with the rocket tank (20) downstream. The upper part of the liquid methane tank (39) is communicated with a high-pressure helium bottle group (24) through a helium gas supplementing pipe to provide high-pressure gas pressure for the liquid methane tank (39).

8. The full subcool liquid methane dispensing method of claim 7, wherein, The liquid methane tank (39) is provided with a liquid methane lower cavity temperature detector (21) and a liquid methane upper cavity temperature detector (22) to measure the liquid methane temperature of the lower part and the upper part of the liquid methane tank (39) cavity, respectively. The supercooled liquid methane filling pipeline (44) between the lower liquid inlet pipe (52) and the upper liquid outlet pipe (53) is provided with a low-temperature circulating pump (14) to circulate and mix the liquid methane in the upper part and the lower part of the liquid methane tank (39), so as to keep the temperature of the liquid methane in the liquid methane tank (39) uniform.

9. The full subcool liquid methane dispensing method of claim 7, wherein, The top gas phase space of the liquid methane tank (39) is connected with a methane cavity pressure gauge (26), and the top of the liquid methane tank (39) is communicated with the atmosphere through a liquid methane tank exhaust pipe (51) for pressure relief.

10. The full subcool liquid methane dispensing method of claim 7, wherein, The liquid methane filling module includes the supercooled liquid methane filling pipeline (44) connecting the supercooled liquid methane module and the rocket tank (20), and the supercooled liquid methane filling pipeline (44) is provided with a supercooled liquid methane filling cut-off valve (15), a flowmeter (16) for measuring the liquid methane flow, and a supercooled liquid methane filling regulating valve (17) for adjusting the liquid methane flow.

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