Full supercooled liquid methane filling system

Abstract

The invention provides a full supercooled liquid methane filling system. The full supercooled liquid methane filling system comprises a refrigerant filling module, a supercooled liquid methane module and a liquid methane filling module. Wherein the refrigerant filling module is connected with a liquid methane supercooling storage tank of the supercooling liquid methane module through a filling pipeline and is used for supercooling liquid methane in the liquid methane storage tank. And the supercooled liquid methane module is connected with the liquid methane filling module through a pipeline and is used for filling cooled liquid methane into the rocket storage tank. The liquid methane supercooling storage tank comprises a liquid methane storage tank and a heat preservation layer located outside the liquid methane storage tank, and a refrigerant interlayer is arranged between the liquid methane storage tank and the heat preservation layer and used for containing the refrigerant provided by the refrigerant filling module and cooling liquid methane in the liquid methane storage tank. According to the filling system, the liquid methane supercooling efficiency can be improved, liquid methane crystallization is avoided, the supercooling process is stable and efficient, and the economic benefit of the supercooling filling process is high.

Description

Technical Field

[0001] The invention relates to the technical field of cryogenic liquid rocket filling, in particular to liquid methane filling, and specifically to a fully subcooled liquid methane filling system. Background Art

[0002] With the rapid development of the aerospace industry, various technologies involved in the rocket field have also achieved rapid progress. In particular, with the development of cryogenic launch vehicle technology, the new propellant combination of liquid oxygen and liquid methane has attracted widespread attention and is increasingly being used in practice. At present, the liquid methane supercooling technology is generally a supercooler heat exchange, that is, the liquid methane is supercooled and filled on the day of filling. The filling control requirements are high and the liquid methane temperature is too low, there is a risk of crystallization, which is easy to block the supercooler and seriously affect the launch mission.

[0003] When using a subcooler to subcool liquid methane, when an emergency occurs or filling is completed and filling needs to be stopped, in order to prevent crystallization, the liquid methane cannot be stopped immediately. The liquid methane flow can only be stopped after the liquid nitrogen leaks to a safe liquid level, resulting in waste. With the development of new cryogenic rocket and aerospace technology, there is an urgent need for a liquid methane subcooling filling system that can meet high frequency, full subcooling, large subcooling capacity, safety, stability, and economy. Summary of the invention

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

[0005] The present invention provides a fully supercooled liquid methane filling system, which includes: a refrigerant filling module, a supercooled liquid methane module and a liquid methane filling module, wherein the refrigerant filling module is connected to the liquid methane supercooling storage tank of the supercooled liquid methane module through a filling pipeline, and is used to supercool the liquid methane in the liquid methane storage tank; the supercooled liquid methane module pipeline is connected to the liquid methane filling module, and is used to fill the rocket tank with cooled liquid methane; the liquid methane supercooling storage tank includes a liquid methane storage tank and an insulation layer located outside the liquid methane storage tank, and a refrigerant interlayer is provided between the liquid methane storage tank and the insulation layer, which is used to accommodate the refrigerant provided by the refrigerant filling module and cool the liquid methane in the liquid methane storage tank.

[0006] Furthermore, the refrigerant filling module includes: a refrigerant storage tank, which is connected to the liquid methane supercooling storage tank through a refrigerant filling pipeline to provide refrigerant for liquid methane; the refrigerant filling pipeline is connected to a refrigerant tank truck for providing refrigerant through a refrigerant transfer pipeline; the top and bottom of the refrigerant storage tank are connected through a self-pressurizing pipeline, which is used to adjust the pressure of the refrigerant storage tank through refrigerant vaporization, thereby adjusting the refrigerant temperature; the top of the refrigerant storage tank is connected to the top of the refrigerant interlayer through a refrigerant pressurizing pipeline, which is used to pressurize the refrigerant interlayer; a refrigerant tank exhaust pipe is provided at the top of the refrigerant storage tank to adjust the pressure of the refrigerant storage tank.

[0007] Furthermore, the self-pressurizing pipeline is provided with a self-pressurizing stop valve, a self-pressurizing regulating valve and a self-pressurizing carburetor in sequence.

[0008] Furthermore, the upstream of the refrigerant storage tank exhaust pipe is connected to the gas phase space at the top of the refrigerant storage tank through two parallel pipes, and the downstream of the refrigerant storage tank exhaust pipe is merged into one pipe and connected to the atmosphere; on the parallel pipes upstream of the refrigerant storage tank exhaust pipe, one of the pipes is provided with a safety relief valve, and the other pipe is provided with a refrigerant storage tank exhaust valve.

[0009] In an embodiment of the present invention, the supercooled liquid methane module includes the liquid methane supercooled storage tank, the bottom of the liquid methane storage tank in the liquid methane supercooled storage tank is provided with a lower liquid inlet pipe, and the upper part is provided with an upper liquid outlet pipe; the lower liquid inlet pipe is connected to the liquid methane tank truck through a liquid methane transfer pipeline, for providing liquid methane; the upper liquid outlet pipe is connected to the lower liquid inlet pipe through a supercooled liquid methane filling pipeline, the supercooled liquid methane filling pipeline is connected to the liquid methane storage tank through the lower liquid inlet pipe upstream, and is connected to the rocket tank downstream; the upper part of the liquid methane storage tank is connected to a high-pressure helium cylinder group through a helium gas supply pipe, for providing high-pressure air pressure to the liquid methane storage tank.

[0010] Furthermore, the liquid methane storage tank is provided with a liquid methane lower cavity temperature meter and a liquid methane upper cavity temperature meter, which are respectively used to measure the liquid methane temperature in the lower and upper parts of the liquid methane storage tank cavity; and a low-temperature circulation pump is provided on the supercooled liquid methane filling pipeline between the lower liquid inlet pipe and the upper liquid 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 keep the temperature of the liquid methane in the liquid methane storage tank uniform.

[0011] Furthermore, an upper interlayer cavity level gauge is provided on the upper part of the insulation layer, and a lower interlayer cavity level gauge is provided on the lower part of the insulation layer. Both the upper interlayer cavity level gauge and the lower interlayer cavity level gauge are connected to the refrigerant interlayer for measuring the refrigerant liquid level.

[0012] Furthermore, the gas phase space at the top of the liquid methane storage tank is connected to a methane cavity pressure gauge, and the top of the liquid methane storage tank is connected to the atmosphere for pressure relief through a liquid methane storage tank exhaust pipe; the gas phase space at the top of the refrigerant interlayer is connected to an interlayer cavity pressure gauge, and the top of the refrigerant interlayer is connected to the atmosphere for pressure relief through an interlayer cavity exhaust pipe.

[0013] In an embodiment of the present invention, the liquid methane filling module includes the supercooled liquid methane filling pipeline connecting the supercooled liquid methane module and the rocket tank, and the supercooled liquid methane filling pipeline is provided with a supercooled liquid methane filling shut-off valve, a flowmeter for measuring the liquid methane flow rate, and a supercooled liquid methane filling regulating valve for regulating the liquid methane flow rate.

[0014] Furthermore, a liquid methane inlet temperature detector and a supercooled liquid methane filling valve are provided at one end of the supercooled liquid methane filling pipeline close to the rocket tank.

[0015] According to the above embodiments, the fully subcooled liquid methane filling system provided by the present invention has at least one of the following benefits: 1. The technology provided by the present invention can realize supercooling and storage of liquid methane in a sandwich 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, avoiding the risk of ice blockage caused by overcooling of the supercooler on the refueling day, thereby affecting the rocket launch.

[0016] 2. The supercooling system of the present application can be used to prepare a large amount of supercooled liquid methane. The supercooling flow rate is not limited by the heat exchange capacity of the heat exchanger, and a larger flow rate of liquid methane can be provided for filling. It has the ability to provide large-volume and large-flow supercooling filling for medium and large cryogenic liquid rockets.

[0017] 3. In addition, by adopting the subcooling system of the present application, there is no need for online subcooling on the day of filling, and large-flow filling can be achieved without being limited by the capacity of the heat exchanger, greatly shortening the filling time.

[0018] 4. The method provided by the present invention first fills the refrigerant and then the liquid methane. The refrigerant is added first, and the refrigerant can reduce the temperature of the interlayer and inner cylinder of the liquid methane storage tank to play a pre-cooling role. The refrigerant used is economical and has lower cost.

[0019] 5. The filling method provided by the present invention can stop the flow of supercooled liquid methane at any time without worrying about ice blockage of the supercooler, and the response speed to emergency situations is faster.

[0020] 6. The triple point temperature of liquid argon is 83.81K, which is 6.85K lower than the triple point temperature of liquid methane, 90.66K. Liquid nitrogen is 63.15K, which is 27.51K lower than the triple point temperature of liquid methane, 90.66K. The temperature difference between the triple point of the refrigerant of the present application and liquid methane is small, so the risk of liquid methane crystallization is smaller, and the temperature of the refrigerant of the present application is easier to control by increasing the pressure to control the temperature to be above the crystallization temperature of liquid methane. At the same time, liquid argon is purchased from the market and is a common and low-cost refrigerant.

[0021] 7. The helium used for the internal pressure replenishment and pressurization of the liquid methane storage tank of the present application has extremely low solubility in liquid methane and will not pollute the liquid methane. Moreover, helium is an inert gas and is safer. In view of the high price of helium, in order to reduce costs, the present application also sets up a helium recovery device, which uses a booster pump to re-compress the helium into a high-pressure helium cylinder to achieve the reuse of helium, greatly reducing the launch cost.

[0022] It should be understood that the above general description and the following detailed description are merely exemplary and illustrative and are not intended to limit the scope of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The following drawings are part of the specification of the present invention, and illustrate exemplary embodiments of the present invention. Together with the description of the specification, the accompanying drawings are used to explain the principles of the present invention.

[0024] Figure 1 This is a structural schematic diagram of a fully subcooled liquid methane filling system provided by the present invention.

[0025] Description of reference numerals: 1-refrigerant storage tank, 2-self-pressurizing stop valve, 3-self-pressurizing regulating valve, 4-self-pressurizing vaporizer, 5-first refrigerant temperature detector, 6-refrigerant filling shut-off valve, 7-refrigerant pipeline filter, 8-refrigerant filling regulating valve, 9-second refrigerant temperature detector, 10-refrigerant tank car, 11-refrigerant transfer shut-off valve; 12-liquid methane tank truck, 13-liquid methane transfer cut-off valve, 14-cryogenic circulation pump, 15-supercooled liquid methane filling cut-off valve, 16-flow meter, 17-supercooled liquid methane filling regulating valve, 18-liquid methane inlet temperature detector, 19-supercooled liquid methane filling valve, 20-rocket tank; 21-liquid methane lower chamber temperature detector, 22-liquid methane upper chamber temperature detector, 23-high-pressure booster pump, 24-high-pressure helium cylinder group, 25-high-pressure helium pressure reducing valve, 26-methane chamber pressure gauge; 27-gas discharge regulating valve, 28-argon air temperature device, 29-interlayer cavity exhaust pipe, 30-interlayer cavity pressure gauge, 31-interlayer cavity pressure supplement regulating valve, 32-interlayer upper cavity liquid level gauge, 33-interlayer lower cavity liquid level gauge, 34-pressure supplement cut-off valve, 35-safety relief valve, 36-refrigerant storage tank exhaust pipe, 37 refrigerant storage tank pressure gauge, 38-third refrigerant temperature meter; 39-liquid methane storage tank, 40-insulation layer; 41-refrigerant transfer pipeline, 42-refrigerant filling pipeline, 43-liquid methane transfer pipeline, 44-supercooled liquid methane filling pipeline, 45-refrigerant boosting pipeline; 46-pressure compensation regulating valve, 47-liquid methane circulation cut-off valve, 48-refrigerant storage tank exhaust valve, 49-liquid methane storage tank exhaust valve; 50-self-pressurizing pipeline, 51-liquid methane storage tank exhaust pipe, 52-lower liquid inlet pipe, 53-upper liquid outlet pipe, 54-refrigerant interlayer. DETAILED DESCRIPTION

[0026] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0027] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to those skilled in the art. The present application description and examples are exemplary only.

[0028] The present invention provides a fully subcooled liquid methane filling system, such as Figure 1 The structure diagram of the liquid methane filling system is shown. In a specific embodiment, the filling system includes: a refrigerant filling module, a supercooled liquid methane module and a liquid methane filling module. The refrigerant filling module is connected to the liquid methane supercooling storage tank of the supercooled liquid methane module through a filling pipeline, which is used to supercool the liquid methane in the liquid methane storage tank.

[0029] The supercooled liquid methane module pipeline is connected to the liquid methane filling module, which is used to fill the rocket tank 20 with cooled liquid methane.

[0030] Furthermore, the liquid methane supercooling tank includes a liquid methane tank 39 and an insulation layer 40 located outside the liquid methane tank 39. A refrigerant interlayer 54 is provided between the liquid methane tank 39 and the insulation layer 40 for accommodating the refrigerant provided by the refrigerant filling module to cool the liquid methane in the liquid methane tank 39.

[0031] 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 supercooling storage tank via a refrigerant filling pipeline 42 to provide refrigerant for the liquid methane.

[0032] The refrigerant filling pipeline 42 is connected to the refrigerant tank truck 10 for providing refrigerant through the refrigerant transfer pipeline 41. The refrigerant transfer pipeline 41 is provided with a refrigerant transfer cut-off valve 11 for controlling the opening and closing of the refrigerant transfer. In addition, the refrigerant filling pipeline 42 between the refrigerant transfer pipeline 41 and the refrigerant storage tank 1 is provided with a refrigerant pipeline filter 7 for filtering the refrigerant, a refrigerant filling cut-off valve 6 for controlling the refrigerant filling and transfer, and a first refrigerant temperature measuring device 5 for measuring the refrigerant temperature.

[0033] A refrigerant filling regulating valve 8 for controlling the refrigerant filling and a second refrigerant temperature measuring device 9 for measuring the refrigerant temperature are sequentially arranged on the refrigerant filling pipeline 42 between the refrigerant transfer pipeline 41 and the liquid methane supercooling storage tank.

[0034] The top and bottom of the refrigerant storage tank 1 are connected by a self-pressurizing pipeline 50, which is used to adjust the pressure of the refrigerant storage tank 1 through refrigerant gasification, thereby adjusting the refrigerant temperature and increasing the pressure for the discharge of the refrigerant, which is more conducive to providing refrigerant for the supercooled liquid methane module. The self-pressurizing pipeline 50 is connected to the bottom of the refrigerant storage tank 1 upstream and the top of the refrigerant storage tank 1 downstream. The self-pressurizing stop valve 2, the self-pressurizing regulating valve 3 and the self-pressurizing vaporizer 4 are sequentially arranged on the upstream part of the self-pressurizing pipeline 50, which are used to realize the refrigerant gasification and replenish it into the upper gas phase space of the refrigerant storage tank 1 through the pipeline, thereby increasing the internal air pressure of the refrigerant storage tank 1 and changing the refrigerant temperature. In addition, by increasing the air pressure inside the refrigerant storage tank 1, it is also beneficial to transport the refrigerant to the supercooled liquid methane module, thereby achieving a supercooling effect.

[0035] In addition, the top of the refrigerant storage tank 1 is connected to the top of the refrigerant interlayer 54 through a refrigerant boosting pipeline 45, which is used to boost the pressure of the refrigerant interlayer 54. The refrigerant boosting pipeline 45 is connected to the refrigerant storage tank 1 upstream and to the gas phase space at the top of the refrigerant interlayer 54 downstream, and the refrigerant boosting pipeline 45 is provided with a pressure compensation cut-off valve 34 and an interlayer cavity pressure compensation regulating valve 31 in sequence from upstream to downstream. In addition, the gas phase space at the top of the refrigerant interlayer 54 is connected to an interlayer cavity pressure gauge 30, which is used to detect the pressure of the interlayer cavity in real time, and then dynamically adjust the pressure inside the refrigerant interlayer 54 by controlling the interlayer cavity pressure compensation regulating valve 31.

[0036] A refrigerant tank exhaust pipe 36 is provided at the top of the refrigerant tank 1 to adjust the pressure of the refrigerant tank 1. Specifically, the upstream of the refrigerant tank exhaust pipe 36 is connected to the gas phase space at the top of the refrigerant tank 1 through two parallel pipes, and the downstream of the refrigerant tank exhaust pipe 36 is merged into one pipe and connected to the atmosphere.

[0037] On the parallel pipelines upstream of the refrigerant storage tank exhaust pipe 36, one of the pipelines is provided with a safety relief valve 35, and the other pipeline is provided with a refrigerant storage tank exhaust valve 48.

[0038] In addition, a refrigerant tank pressure gauge 37 is provided on the top of the refrigerant tank 1 for detecting the air pressure inside the refrigerant tank 1 in real time, and adjusting the internal pressure of the refrigerant tank 1 through the safety relief valve 35 on the refrigerant tank exhaust pipe 36 and the refrigerant tank exhaust valve 48.

[0039] In addition, a third refrigerant temperature detector 38 is provided on the refrigerant storage tank 1 for detecting the temperature of the refrigerant inside the refrigerant storage tank 1 in real time and adjusting the temperature by adjusting the self-pressurization structure.

[0040] In a specific embodiment of the present invention, the supercooled liquid methane module includes a liquid methane supercooling storage tank, and the liquid methane storage tank 39 in the liquid methane supercooling storage tank has a lower liquid inlet pipe 52 at the bottom and an upper liquid outlet pipe 53 at the top. The lower liquid inlet pipe 52 is connected to the liquid methane tank truck 12 through the liquid methane transfer pipeline 43 to provide liquid methane. The liquid methane transfer pipeline 43 is provided with a liquid methane transfer cut-off valve 13 to control the transfer of liquid methane.

[0041] The upper liquid outlet pipe 53 is connected to the lower liquid inlet pipe 52 through the supercooled liquid methane filling pipeline 44. The supercooled liquid methane filling pipeline 44 is connected to the liquid methane storage tank 39 upstream through the lower liquid inlet pipe 52 and connected to the rocket tank 20 downstream, so as to provide supercooled liquid methane to the rocket tank 20.

[0042] The upper part of the liquid methane storage tank 39 is connected to a high-pressure helium cylinder group 24 through a helium gas supply pipe, which is used to provide high-pressure gas pressure for the liquid methane storage tank 39, increase the gas pressure in the liquid methane storage tank 39, and facilitate the filling of supercooled liquid methane into the rocket tank 20 through the pipeline. The gas phase space at the upper part of the liquid methane storage tank 39 is connected to a methane cavity pressure gauge 26, which is used to detect the internal pressure of the liquid methane storage tank 39 in real time. The helium gas supply pipe connecting the high-pressure helium cylinder group 24 to the liquid methane storage tank 39 is provided with a high-pressure helium pressure reducing valve 25 and a pressure compensation regulating valve 46, which are used to dynamically adjust the pressure increase in the liquid methane storage tank 39 according to the pressure value detected by the methane cavity pressure gauge 26.

[0043] In addition, there is a helium recovery pipeline between the high-pressure helium cylinder group 24 and the liquid methane storage tank 39, and a high-pressure booster pump 23 is provided on the helium recovery pipeline, which is used to recover the helium in the gas phase space inside the liquid methane storage tank 39 to the high-pressure helium cylinder group 24 through the helium recovery pipeline. Preferably, the booster gas helium can also be any gas that is insoluble in liquid methane, inert, highly safe, and economical.

[0044] Furthermore, the liquid methane storage tank 39 is provided with a liquid methane lower chamber temperature detector 21 and a liquid methane upper chamber temperature detector 22, which are used to measure the liquid methane temperature at the lower and upper parts of the liquid methane storage tank 39 cavity, respectively.

[0045] In addition, a low-temperature circulation pump 14 is provided on the supercooled liquid methane filling pipeline 44 between the lower liquid inlet pipe 52 and the upper liquid outlet pipe 53, which is used to circulate and mix the liquid methane in the upper and lower parts of the liquid methane storage tank 39 to maintain a uniform temperature of the liquid methane in the liquid methane storage tank 39. During the preparation of the supercooled liquid methane or after long-term storage, there will be a certain temperature difference between the liquid methane temperatures in the upper and lower parts of the inner cavity of the liquid methane storage tank 39. In order to make the liquid methane temperature inside the liquid methane storage tank 39 similar or without a temperature difference, it is necessary to fully mix the liquid methane in the inner cavity of the liquid methane storage tank 39 so that its overall temperature tends to be consistent.

[0046] In a specific embodiment of the present invention, the top of the liquid methane storage tank 39 is connected to the atmosphere for pressure relief through a liquid methane storage tank exhaust pipe 51. A liquid methane storage tank exhaust valve 49 is provided on the liquid methane storage tank exhaust pipe 51 to control the exhaust of the liquid methane storage tank 39 into the atmosphere, so as to facilitate the transfer and filling of liquid methane.

[0047] In addition, the top of the cryogen interlayer 54 is connected to the atmosphere for pressure relief through the interlayer cavity exhaust pipe 29, which is used for refrigerant filling and pressure relief. The interlayer cavity exhaust pipe 29 is provided with a gas discharge regulating valve 27 and an argon gas temperature controller 28.

[0048] In the embodiment of the present invention, there are two transfer processes of liquid methane. One transfer method is: open the liquid methane transfer cut-off valve 13, open the liquid methane storage tank exhaust valve 49, and then increase the pressure in the liquid methane tank truck 12 through the liquid methane booster vaporizer, and use the pressure difference to transport the liquid methane through the lower liquid inlet pipe 52 to the liquid methane storage tank 39.

[0049] Another transfer method is: open the liquid methane transfer shut-off valve 13 and the liquid methane circulation shut-off valve 47, and start the low-temperature circulation pump 14 to transport the liquid methane in the liquid methane tank truck 12 to the liquid methane storage tank 39 through the upper liquid outlet pipe 53.

[0050] In a specific embodiment of the present invention, an upper interlayer cavity level gauge 32 is provided on the upper part of the thermal insulation layer 40, and an lower interlayer cavity level gauge 33 is provided on the lower part of the thermal insulation layer 40. The upper interlayer cavity level gauge 32 and the lower interlayer cavity level gauge 33 are both connected to the refrigerant interlayer 54 for measuring the refrigerant level. When it is detected that the refrigerant level is lower than the lower interlayer cavity level gauge 33, the refrigerant storage tank 1 is controlled to add refrigerant to the refrigerant interlayer 54. When it is detected that the refrigerant level reaches or exceeds the upper interlayer cavity level gauge 32, the refrigerant storage tank 1 is controlled to stop adding refrigerant to the refrigerant interlayer 54.

[0051] In a specific embodiment of the present invention, the liquid methane filling module includes a 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 shut-off valve 15, a flow meter 16 for measuring the liquid methane flow rate, and a supercooled liquid methane filling regulating valve 17 for regulating the liquid methane flow rate.

[0052] Furthermore, a liquid methane inlet temperature detector 18 and a supercooled liquid methane filling valve 19 are provided at one end of the supercooled liquid methane filling pipeline 44 close to the rocket tank 20 .

[0053] In the embodiment of the present invention, there are two filling processes of liquid methane. One filling method is: open the supercooled liquid methane filling shut-off valve 15, close the liquid methane transfer shut-off valve 13, open the supercooled liquid methane filling valve 19, pressurize the liquid methane storage tank 39 through the high-pressure helium cylinder group 24, and squeeze the supercooled liquid methane into the rocket tank 20 by using the pressure difference.

[0054] Another filling method is: open the supercooled liquid methane filling shut-off valve 15, close the liquid methane transfer shut-off valve 13, open the supercooled liquid methane filling valve 19, and then start the low-temperature circulation pump 14 to pump the supercooled liquid methane into the rocket tank 20.

[0055] In a specific embodiment of the present invention, the cryogen is liquid argon. Liquid argon can be replaced with liquid nitrogen or other inert low-temperature medium with a boiling point lower than the boiling point of liquid methane and higher than the freezing point of liquid methane as the cryogen, but the cryogen storage temperature needs to be adjusted simultaneously. If replaced with liquid nitrogen, the cryogen storage tank pressure and the storage tank interlayer pressure need to be increased by about 2.5 times compared with liquid argon.

[0056] The specific liquid methane supercooling and filling steps of the fully subcooled liquid methane filling system provided by the present invention are: First, refrigerant transfer: connect the refrigerant tank truck 10 to the refrigerant transfer pipeline 41, increase the tank truck pressure through the self-pressurizing vaporizer of the refrigerant tank truck 10, open the refrigerant transfer shut-off valve 11, close the refrigerant filling regulating valve 8, open the refrigerant filling shut-off valve 6, open the refrigerant tank exhaust valve 48, and transfer the refrigerant to the refrigerant storage tank 1 through the pressure difference.

[0057] Second, refrigerant temperature control: Because the triple point temperature of liquid argon 83.81K is lower than the triple point temperature of liquid methane 90.66K, 6.85K. Therefore, it is necessary to heat up the liquid argon. The heating method is to increase the pressure of the liquid argon storage tank. The saturation temperature corresponding to the pressure increase increases. Open the self-pressurization stop valve 2 and control the opening of the self-pressurization regulating valve 3. The liquid argon flows from the refrigerant storage tank 1 into the self-pressurization argon vaporizer 4, and the volume increases by about 780 times. After vaporization, the argon gas returns to the gas phase space at the top of the refrigerant storage tank 1. After the volume of the gas in the limited space increases, the pressure inside the refrigerant storage tank 1 increases. The self-pressurization regulating valve 3 is linked to the refrigerant storage tank pressure gauge 37 to control the opening, and the tank pressure of the refrigerant storage tank 1 is maintained at about 0.15MPa (absolute pressure). The temperature of the liquid argon will gradually rise until it reaches a dynamic equilibrium state corresponding to the saturation temperature of 0.15MPa of about 91K, and the refrigerant temperature control is completed.

[0058] Third, refrigerant filling: close the refrigerant transfer shut-off valve 11, open the refrigerant filling shut-off valve 6, and introduce liquid argon into the refrigerant interlayer 54 of the liquid methane supercooling storage tank. When the pressure of the refrigerant interlayer 54 is greater than 0.15MPa (absolute pressure), the gas discharge regulating valve 27 interlocks the interlayer cavity pressure gauge 30 and opens to release the pressure. When the pressure is lower than 0.1MPa (absolute pressure), the gas discharge regulating valve 27 is interlocked to reduce or close the opening of the gas discharge regulating valve 27 to maintain the pressure of the refrigerant interlayer 54 at 0.15MPa (absolute pressure).

[0059] When the liquid argon level in the cryogen interlayer 54 is lower than the liquid point of the interlayer lower chamber liquid level gauge 33, the opening of the cryogen filling regulating valve 8 is increased. When the liquid argon level is higher than the liquid point of the interlayer upper chamber liquid level gauge 32, the opening of the cryogen filling regulating valve 8 is decreased or closed to complete the cryogen filling.

[0060] When the pressure of the cryogen interlayer 54 is lower than 0.15 MPa (absolute pressure), the pressure of the cryogen interlayer 54 can be supplemented by adjusting the interlayer cavity pressure regulating valve 31 of the interlocking interlayer cavity pressure gauge 30 to maintain the pressure in the interlayer, thereby maintaining the saturation temperature of the liquid argon in the cryogen interlayer 54 from decreasing.

[0061] Fourth, liquid methane transfer: connect the liquid methane tanker 12 to the third liquid methane transfer pipeline 43, close the supercooled liquid methane filling shut-off valve 15, open the liquid methane transfer shut-off valve 13, and increase the pressure in the liquid methane tanker 12 through the liquid methane booster vaporizer. Then open the liquid methane storage tank exhaust valve 49, and transfer the liquid methane into the liquid methane storage tank 39 through the pressure difference. Alternatively, the liquid methane circulation shut-off valve 47 can be opened and the low-temperature circulation pump 14 can be used to transfer the liquid methane into the liquid methane storage tank 39.

[0062] Fifth, liquid methane supercooling: liquid methane and liquid argon exchange heat through the metal wall of the liquid methane storage tank 39. Since the temperature of the refrigerant 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 of liquid methane, the temperature of liquid methane decreases, which leads to a decrease in the volume of liquid methane, an increase in density, and an increase in the gas phase space of the liquid methane storage tank 39. In order to avoid negative pressure in the liquid methane storage tank 39, the methane chamber pressure gauge 26 measures the pressure of the liquid methane storage tank 39, and the pressure-compensating regulating valve 46 is opened in a chain to compensating the inner cylinder of the liquid methane storage tank 39 to atmospheric pressure. Since the solubility of helium and liquid methane is extremely low, the quality of the liquid methane propellant can be ensured to be unaffected. After the liquid methane is cooled, the temperature is slightly higher than or equal to the temperature of the refrigerant liquid argon 91K, completing the process of liquid methane supercooling.

[0063] Sixth, self-circulation of supercooled liquid methane: During the preparation process or long-term storage of supercooled liquid methane, the temperature of liquid methane in the liquid methane storage tank 39 will be uneven. When the liquid methane temperature data measured by the liquid methane lower chamber temperature sensor 21 and the liquid methane upper chamber temperature sensor 22 differ greatly, it indicates that the temperature of supercooled liquid methane in the liquid methane storage tank is uneven. Then open the liquid methane circulation shut-off valve 47, and automatically start the low-temperature circulation pump 14 to fully mix the supercooled liquid methane with uneven temperature until the temperature deviation is reduced or consistent, and the low-temperature circulation pump 14 automatically stops.

[0064] Seventh, filling of supercooled liquid methane: close the liquid methane transfer shut-off valve 13, open the supercooled liquid methane filling shut-off valve 15, open the supercooled liquid methane filling 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 tank 20. Or open the supercooled liquid methane filling shut-off valve 15, close the liquid methane transfer shut-off valve 13, open the supercooled liquid methane filling valve 19, and then start the low-temperature circulation pump 14 to pump the supercooled liquid methane into the rocket tank 20. The supercooled liquid methane filling regulating valve 17 interlocks the flowmeter 16 to control the filling flow to meet the technical requirements of the rocket launch. The liquid methane arrow temperature detector 18 monitors in real time whether the temperature of the supercooled liquid methane meets the rocket arrow temperature requirements. If not, stop the arrow.

[0065] Eighth, helium recovery: after the filling task is completed, the helium in the liquid methane storage tank 39 can be recovered to the high-pressure helium cylinder group 24 by turning on the high-pressure booster pump 23, completing the helium recovery and reducing the filling cost.

[0066] The above description is only an illustrative specific implementation manner of the present invention. Without departing from the concept and principle of the present invention, any equivalent changes and modifications made by those skilled in the art should fall within the scope of protection of the present invention.

Claims

1. A fully subcooled liquid methane filling system, characterized in that: The filling system includes: a refrigerant filling module, a supercooled liquid methane module and a liquid methane filling module, wherein: The refrigerant filling module is connected to the liquid methane supercooling storage tank of the supercooled liquid methane module through a filling pipeline, and is used to supercool the liquid methane in the liquid methane storage tank; The supercooled liquid methane module pipeline is connected to the liquid methane filling module and is used to fill the rocket tank (20) with cooled liquid methane; The liquid methane supercooling storage tank comprises a liquid methane storage tank (39) and a thermal insulation layer (40) located outside the liquid methane storage tank (39), and a refrigerant interlayer (54) is provided between the liquid methane storage tank (39) and the thermal insulation layer (40) for accommodating the refrigerant provided by the refrigerant filling module to cool the liquid methane in the liquid methane storage tank (39).

2. The fully subcooled liquid methane filling system according to claim 1, characterized in that: The refrigerant filling module comprises: a refrigerant storage tank (1), the refrigerant storage tank (1) being connected to the liquid methane supercooling storage tank via a refrigerant filling pipeline (42) to provide refrigerant for the liquid methane; The refrigerant filling pipeline (42) is connected to a refrigerant tank truck (10) for providing refrigerant via a refrigerant transfer pipeline (41); The top and bottom of the refrigerant storage tank (1) are connected via a self-pressurizing pipeline (50) for adjusting the pressure of the refrigerant storage tank (1) by gasifying the refrigerant, thereby adjusting the temperature of the refrigerant; The top of the refrigerant storage tank (1) is connected to the top of the refrigerant interlayer (54) via a refrigerant pressurizing pipeline (45) for pressurizing the refrigerant interlayer (54); A refrigerant tank exhaust pipe (36) is provided at the top of the refrigerant tank (1) for adjusting the pressure of the refrigerant tank (1).

3. The fully subcooled liquid methane filling system according to claim 2, characterized in that: The self-pressurizing pipeline (50) is provided with a self-pressurizing stop valve (2), a self-pressurizing regulating valve (3) and a self-pressurizing carburetor (4) in sequence.

4. The fully subcooled liquid methane filling system according to claim 2, characterized in that: The upstream of the refrigerant storage tank exhaust 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 exhaust pipe (36) is merged into one pipe and connected to the atmosphere; On the parallel pipelines upstream of the refrigerant storage tank exhaust pipe (36), one of the pipelines is provided with a safety relief valve (35), and the other pipeline is provided with a refrigerant storage tank exhaust valve (48).

5. The fully subcooled liquid methane filling system according to claim 1, characterized in that: The supercooled liquid methane module comprises the liquid methane supercooled storage tank, wherein the liquid methane storage tank (39) in the liquid methane supercooled storage tank has a lower liquid inlet pipe (52) at the bottom and an upper liquid outlet pipe (53) at the top; The lower liquid inlet pipe (52) is connected to the liquid methane tanker (12) via the liquid methane transfer pipeline (43) to provide liquid methane; The upper liquid outlet pipe (53) is connected to the lower liquid inlet pipe (52) via a supercooled liquid methane filling pipeline (44); the supercooled liquid methane filling pipeline (44) is connected to the liquid methane storage tank (39) upstream via the lower liquid inlet pipe (52) and is connected to the rocket tank (20) downstream; The upper portion of the liquid methane storage tank (39) is connected to a high-pressure helium cylinder group (24) via a helium gas supply pipe, which is used to provide high-pressure gas pressure for the liquid methane storage tank (39).

6. The fully subcooled liquid methane filling system according to claim 5, characterized in that: The liquid methane storage tank (39) is provided with a liquid methane lower chamber temperature measuring device (21) and a liquid methane upper chamber temperature measuring device (22), which are used to measure the liquid methane temperatures at the lower and upper parts of the chamber of the liquid methane storage tank (39), respectively. A low-temperature circulation pump (14) is provided on the supercooled liquid methane filling pipeline (44) between the lower liquid inlet pipe (52) and the upper liquid outlet pipe (53) for circulating and mixing the liquid methane in the upper and lower parts of the liquid methane storage tank (39) to maintain a uniform temperature of the liquid methane in the liquid methane storage tank (39).

7. The fully subcooled liquid methane filling system according to claim 5, characterized in that: An upper interlayer cavity level gauge (32) is disposed on the upper portion of the thermal insulation layer (40), and a lower interlayer cavity level gauge (33) is disposed on the lower portion of the thermal insulation layer (40). Both the upper interlayer cavity level gauge (32) and the lower interlayer cavity level gauge (33) are connected to the refrigerant interlayer (54) for measuring the refrigerant liquid level.

8. The fully subcooled liquid methane filling system according to claim 5, characterized in that: The gas phase space at the top of the liquid methane storage tank (39) is connected to a methane chamber pressure gauge (26), and the top of the liquid methane storage tank (39) is connected to the atmosphere through a liquid methane storage tank exhaust pipe (51) for pressure relief; The gas phase space at the top of the refrigerant interlayer (54) is connected to an interlayer cavity pressure gauge (30), and the top of the refrigerant interlayer (54) is connected to the atmosphere through an interlayer cavity exhaust pipe (29) for pressure relief.

9. The fully subcooled liquid methane filling system according to claim 5, characterized in that: The liquid methane filling module comprises the subcooled liquid methane filling pipeline (44) connecting the subcooled liquid methane module and the rocket tank (20), and the subcooled liquid methane filling pipeline (44) is provided with a subcooled liquid methane filling shut-off valve (15), a flow meter (16) for measuring the liquid methane flow rate, and a subcooled liquid methane filling regulating valve (17) for regulating the liquid methane flow rate.

10. The fully subcooled liquid methane filling system according to claim 9, characterized in that: A liquid methane inlet temperature detector (18) and a supercooled liquid methane filling valve (19) are provided at one end of the supercooled liquid methane filling pipeline (44) close to the rocket tank (20).

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