Device and method for storing and sealing low-temperature liquids

Abstract

The present invention provides a device for storing and sealing low-temperature liquids, which includes a storage body buried in the soil, the storage body having an inner cavity for storing low-temperature liquids, a refrigeration system acting on the top, bottom and circumferential side walls of the storage body; a pressure regulating system, which is connected to the inner cavity of the storage body and regulates the inner cavity pressure of the storage body by air pressure. Before the low-temperature liquid is injected into the inner cavity, the temperature distribution of the soil around the storage body is regulated under the refrigeration action of the refrigeration system. At the same time, the pressure regulating system regulates the gas pressure in the inner cavity so that moisture migrates and gathers in the soil to form an ice layer. Under the joint action of the refrigeration system and the pressure regulating system, the growth rate and direction of the ice layer in the soil are controlled. By synergistically regulating the wall temperature and inner cavity pressure of the liquid storage body, a specific temperature and pressure distribution can be formed in the soil, guiding moisture to migrate to the expected area and freeze, thereby controlling the growth rate and direction of the ice layer, and obtaining a stable and consistent ice layer as a sealing layer of the storage body, thereby realizing reliable and low-cost underground storage of low-temperature liquids.

Description

Technical Field

[0001] The present invention relates to the technical field of cryogenic liquid storage, and in particular to a cryogenic liquid storage sealing device and method. Background Art

[0002] The demand for cryogenic liquid storage is increasing across industry and science. These cryogenic liquids, such as liquid nitrogen and liquid hydrogen, play a vital role in numerous applications, such as freezing biological specimens in medicine and storing fuel in aerospace. However, conventional cryogenic liquid storage methods present several challenges, including the need for expensive equipment, high energy consumption, and the risk of liquid loss.

[0003] Existing methods for underground liquid storage primarily involve the use of sealed containers or underground tanks. These methods require specialized equipment to ensure the seal and stability of the liquid, as described in JPH09152098A and JP2005082976A. Additionally, some methods utilize groundwater layers for storage, injecting cryogenic liquids into the groundwater layer to form an ice seal, such as described in CN114738657A.

[0004] The disadvantages of sealed containers or underground storage tanks mainly include the following aspects:

[0005] 1. High cost: Designing, building, and installing sealed containers or underground storage tanks requires significant capital investment. These devices often require special materials and engineering designs to ensure the tightness and stability of the liquid, which increases costs.

[0006] 2. High maintenance and management costs: Sealed containers or underground storage tanks require regular maintenance and management to ensure their operation and sealing effectiveness. This includes inspection, cleaning, repair, and replacement of equipment parts, which consumes a lot of resources and manpower.

[0007] However, using groundwater to directly form ice layers faces the following problems:

[0008] 1. Uneven ice layer sealing: Simply injecting cryogenic liquid to form an ice layer makes it difficult to precisely control the growth rate and distribution of the ice layer, which can easily lead to uneven ice layer sealing and the presence of local weak areas.

[0009] 2. Risk of ice lens expansion damage: In frozen soil, if uncontrolled, the excessive growth and expansion of ice lenses can damage the surrounding soil structure and trigger geological disasters. Frost heave pressure can cause storage facilities to shift, deform, or even rupture, posing a safety hazard. Summary of the Invention

[0010] The purpose of the present invention is to accurately control the growth rate and direction of the ice layer through ice lens active control technology, so as to obtain a stable and consistent ice layer as the sealing layer of the reservoir, and realize reliable and low-cost underground storage of cryogenic liquids.

[0011] In order to solve the above technical problems, the present invention provides a low-temperature liquid storage and sealing device, which includes: a storage body buried in the soil, the storage body having an inner cavity for storing low-temperature liquid; a refrigeration system acting on the top, bottom and circumferential side walls of the storage body; a pressure regulating system, which is connected to the inner cavity of the storage body and regulates the pressure in the inner cavity of the storage body by air pressure; before the low-temperature liquid is injected into the inner cavity, the temperature distribution of the soil around the storage body is adjusted under the refrigeration action of the refrigeration system, and at the same time, the pressure regulating system regulates the gas pressure in the inner cavity so that moisture migrates and accumulates in the soil to form an ice layer. Under the joint action of the refrigeration system and the pressure regulating system, the growth rate and direction of the ice layer in the soil can be controlled.

[0012] Furthermore, the storage body is buried in modified soil with low thermal conductivity and high strength. Under the joint action of the refrigeration system and the pressure regulation system, the growth rate and direction of the ice layer in the modified soil can be controlled.

[0013] Furthermore, the modified soil is prepared by mixing natural soil with additives such as diatomaceous earth and bentonite in appropriate proportions.

[0014] Furthermore, it also includes a monitoring mechanism for monitoring the wall temperature and inner cavity pressure of the storage body. During the growth of the ice layer, the refrigerant flow and inner cavity pressure are dynamically adjusted by real-time monitoring of the wall temperature and inner cavity pressure of the storage body, so that the ice layer grows evenly and slowly in the modified soil.

[0015] Furthermore, the refrigeration system includes a heat exchanger and a circulating refrigerator. The heat exchanger acts on the top, bottom and circumferential side walls of the storage body. The circulating refrigerator is connected to the heat exchanger pipeline and circulates the refrigerant to the heat exchanger through the pipeline.

[0016] Furthermore, the heat exchanger includes a first heat exchanger arranged at the top of the inner cavity, a second heat exchanger arranged on the circumferential side wall of the inner cavity, and a third heat exchanger arranged at the bottom of the inner cavity. The circulating refrigerator includes a first circulating refrigerator connected to the first heat exchanger pipeline, a second circulating refrigerator connected to the second heat exchanger pipeline, and a third circulating refrigerator connected to the third heat exchanger pipeline.

[0017] Furthermore, a flexible enclosure structure is set up around the reservoir, and modified soil is filled in the enclosure structure. When the ice growth generates pressure, the enclosure structure can allow a certain degree of slip deformation, so that the pressure can be transmitted to the critical area of ​​ice growth, ensuring the uniform growth of the ice layer.

[0018] Furthermore, the enclosure structure includes flexible blocking members arranged at the top and bottom of the storage body, and a plurality of flexible connecting plates arranged around the storage body and extending radially toward the storage body. The diameter of the blocking member is larger than the diameter of the storage body. The connecting plates connect the flexible blocking members at the top and bottom. The adjacent connecting plates and the blocking members at the top and bottom together constitute a receiving groove filled with modified soil.

[0019] Furthermore, the storage body includes an inner cavity support structure, an upper flange, a neck tube and an upper end cover. The support structure and the upper flange are made of stainless steel to provide sufficient strength and low-temperature resistance. The upper flange is arranged on the top of the inner cavity support structure, and the neck tube is sleeved with the upper flange; the upper end cover is detachably arranged at the upper end of the storage body and is connected to the inner cavity through the neck tube.

[0020] Furthermore, the neck tube is made of PTFE material. In a low temperature environment, the neck tube is locked by utilizing the shrinkage deformation of the upper flange made of stainless steel, thereby ensuring a sealing connection between the upper flange and the neck tube.

[0021] It can be seen from the above technical solution that the beneficial effects of the present invention are: by synergistically adjusting the wall temperature and internal cavity pressure of the liquid storage body, a specific temperature and pressure distribution can be formed in the soil, guiding moisture to migrate to the desired area and freeze, thereby controlling the growth rate and direction of the ice layer, and obtaining a stable and consistent ice layer as the sealing layer of the reservoir, realizing reliable and low-cost underground storage of cryogenic liquids. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a planar schematic diagram of the low-temperature liquid storage sealing device provided by the present application.

[0023] Figure 2 It is a schematic diagram of the three-dimensional structure of the low-temperature liquid storage and sealing device provided in this application.

[0024] The reference numerals are as follows: 1-side wall heat exchanger connecting pipe, 2-second circulation refrigerator, 3-upper end cover, 4-neck pipe, 5-support structure, 6-enclosing structure, 7-modified soil, 8-second heat exchanger, 9-third heat exchanger, 10-bottom heat exchanger connecting pipe, 11-third circulation refrigerator, 12-top heat exchanger connecting pipe, 13-first circulation refrigerator, 14-drain pipe, 15-first heat exchanger, 16-injection pipe, 17-soil environment. DETAILED DESCRIPTION

[0025] Typical embodiments embodying the features and advantages of the present invention are described in detail in the following description. It should be understood that the present invention is capable of various variations in different embodiments without departing from the scope of the present invention, and that the descriptions and illustrations herein are intended to be illustrative rather than limiting.

[0026] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the said features. In the description of the present application, "multiple" means two or more, unless otherwise clearly and specifically defined.

[0027] In order to further illustrate the principle and structure of the present invention, preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0028] See also Figure 1-2 This embodiment provides a sealed cryogenic liquid storage device comprising a reservoir, a refrigeration system, and a pressure regulation system. The reservoir has an inner cavity for storing cryogenic liquid and is buried in the soil. The refrigeration system acts on the top, bottom, and circumferential sidewalls of the reservoir. The pressure regulation system communicates with the inner cavity and regulates the pressure within the cavity through air pressure. Before the cryogenic liquid is injected, the refrigeration system and pressure regulation system are activated. The refrigeration system regulates the temperature distribution of the soil surrounding the reservoir, while the pressure regulation system adjusts the gas pressure within the inner cavity. This pressure is transmitted through the reservoir to the surrounding soil, thereby adjusting the soil cover pressure. This causes moisture to migrate and accumulate in the soil to form an ice layer. The combined action of the refrigeration system and the pressure regulation system controls the growth rate and direction of the ice layer within the soil.

[0029] Specifically, when the temperature drops, the temperature of the soil layer in contact with it also drops accordingly. Because the freezing point of water varies with pressure but is typically well below ambient temperature, moisture in the soil migrates from high-temperature to low-temperature areas due to temperature differences before reaching its freezing point. In areas where the temperature is sufficiently low, the moisture in the soil begins to freeze. However, even at temperatures below the bulk melting point of water, unfrozen water still exists. This is because long-range intermolecular forces (such as van der Waals forces) between soil particles and ice cause the ice to melt, forming a liquid film between the soil particles and the ice. Driven by the soil temperature and pressure gradients, the unfrozen water flows toward the freezing front. By adjusting the gas pressure within the cavity, the direction and rate of water migration in the soil voids can be altered. Decreasing or increasing the cavity pressure affects the pressure gradient. For example, when the cavity pressure decreases, the pressure gradient drives the unfrozen water to migrate toward the low-pressure region (i.e., the ice lens growth zone), accelerating the growth of the ice layer. Conversely, increasing the cavity pressure slows this process. By synergistically regulating the wall temperature and internal cavity pressure of the liquid storage body, a specific temperature and pressure distribution can be formed in the modified soil 7, guiding the water to migrate to the desired area and freeze, thereby controlling the growth rate and direction of the ice layer.

[0030] Furthermore, a layer of modified soil 7 is placed outside the liquid reservoir to serve as a thermal insulation layer. Modified soil 7 is a mixture of natural soil and additives (such as diatomaceous earth and bentonite) in appropriate proportions, resulting in low thermal conductivity and high strength. The refrigeration system and modified soil 7 regulate the temperature distribution within the soil, allowing water to migrate and accumulate within the soil, forming an ice layer.

[0031] Specifically, modified soil 7 not only improves the system's thermal insulation performance but also allows moisture to be more precisely affected by temperature gradients. When the refrigeration system exchanges heat with modified soil 7, the low thermal conductivity of modified soil 7 slows the transfer of heat through the soil, enabling the system to more precisely control the temperature distribution within the soil. This allows the migration and accumulation of moisture within the soil to be more precisely influenced by the temperature gradient, resulting in the formation of a uniform, stable ice layer in a specific area. Modified soil 7 also possesses high strength, capable of withstanding the stresses generated by ice growth and deformation, reducing the risk of damage to the surrounding soil structure.

[0032] Furthermore, it also includes a monitoring mechanism (not shown in the figure), which is used to monitor the wall temperature and inner cavity pressure of the storage body. During the growth of the ice layer, the inner cavity pressure and wall temperature of the liquid storage body are monitored in real time, the refrigerant flow and inner cavity gas pressure are dynamically adjusted, and the growth rate and direction of the ice layer are accurately controlled to avoid local weak areas and excessive expansion problems.

[0033] Furthermore, the above-mentioned refrigeration system includes a heat exchanger and a circulating refrigerator. The heat exchanger acts on the top, bottom and circumferential side walls of the storage body. The circulating refrigerator is connected to the heat exchanger pipeline and circulates the refrigerant to the heat exchanger through the pipeline.

[0034] Specifically, the heat exchanger includes a first heat exchanger 15 arranged at the top of the inner cavity, a second heat exchanger 8 arranged on the circumferential side wall of the inner cavity, and a third heat exchanger 9 arranged at the bottom of the inner cavity. The circulating refrigerator includes a first circulating refrigerator 13 connected to the first heat exchanger 15 by pipeline, a second circulating refrigerator 2 connected to the second heat exchanger 8 by pipeline, and a third circulating refrigerator 11 connected to the third heat exchanger 9 by pipeline. The above-mentioned first, second and third heat exchangers 9 can adopt various forms such as pipeline type or plate-fin type.

[0035] The innovation of the present invention lies in regulating the growth rate of the ice lens by controlling the inner cavity pressure and wall temperature of the liquid storage reservoir. Specifically, by adjusting the temperature of the side walls, top surface, and bottom surface through the refrigeration system, and by adjusting the inner cavity gas pressure, the growth rate and direction of the ice lens in the modified soil 7 can be controlled. Before the low-temperature liquid is injected, the temperature of the modified soil 7 is first lowered by circulating the refrigerant so that it freezes into an ice layer. During the growth of the ice layer, by real-time monitoring of the temperature and pressure of each part, the refrigerant flow rate and the inner cavity pressure are dynamically adjusted, so that the ice layer grows evenly and slowly in the modified soil 7 until a complete ice layer of the desired thickness is formed. In this way, a uniform and continuous ice layer can be formed on the periphery of the modified soil 7, which plays a reliable sealing role, while preventing excessive growth of the ice layer and significant changes in the geological landscape.

[0036] Furthermore, to accommodate the growth and deformation of the ice layer, a flexible enclosure structure 6 is installed around the liquid reservoir. This enclosure structure 6 is made of polytetrafluoroethylene (PTFE) or other materials with low adhesion. This allows for a certain degree of slippage and deformation when the ice layer grows and generates pressure, allowing the pressure to be transferred to the critical area where the ice lens grows, ensuring uniform growth of the ice layer.

[0037] As shown in the figure, the enclosure structure 6 includes flexible blocking members arranged at the top and bottom of the storage body, and a plurality of flexible connecting plates arranged around the storage body and extending radially toward the storage body. The diameter of the blocking member is larger than the diameter of the storage body. The connecting plates connect the flexible blocking members at the top and bottom. The adjacent connecting plates and the blocking members at the top and bottom together constitute a receiving groove filled with modified soil 7.

[0038] Furthermore, the storage body includes an inner cavity support structure 5, an upper flange, a neck tube, and an upper end cap 3. The support structure 5 and the upper flange are made of stainless steel to provide sufficient strength and low-temperature resistance. The upper flange is arranged on the top of the inner cavity support structure 5, and the neck tube is connected to the upper flange. The upper end cap 3 is detachably arranged at the upper end of the storage body and communicates with the inner cavity through the neck tube. The neck tube is made of polytetrafluoroethylene (PTFE) or other materials with a linear expansion coefficient much smaller than that of stainless steel. In this way, in a low-temperature environment, the stainless steel flange will produce greater shrinkage deformation, firmly locking the PTFE neck tube to form a reliable sealing connection. The neck tube is also provided with an injection pipe 16 and a discharge pipe 14, which are used for injecting and extracting cryogenic liquids, respectively.

[0039] During cryogenic liquid storage, the refrigeration system continuously supplies refrigerant to the refrigeration and heat exchange device, maintaining the ice layer in a frozen state. When the cryogenic liquid needs to be withdrawn from the reservoir, it can be removed through the drain pipe 14 on the neck tube. During this process, the internal cavity pressure and refrigerant flow rate are adjusted to control the rate of cryogenic liquid discharge and maintain the stability of the ice layer.

[0040] The cryogenic liquid storage and sealing device of the present invention utilizes the principles of ice lens growth and the differential linear expansion effect of materials to achieve efficient and safe cryogenic liquid storage through precise control of pressure and temperature. Compared with traditional underground storage tank solutions, this invention offers advantages such as low construction and maintenance costs, high system stability, and minimal environmental impact. This technical solution is applicable not only to the storage of cryogenic liquids such as liquid nitrogen and liquid hydrogen, but can also be expanded to the storage of other cryogenic fluids such as natural gas and liquefied petroleum gas.

[0041] While the present invention has been described with reference to several exemplary embodiments, it should be understood that the terms used are intended to be illustrative and exemplary rather than restrictive. Since the present invention can be embodied in many forms without departing from the spirit or essence of the invention, it should be understood that the above-described embodiments are not limited to any of the foregoing details, but should be interpreted broadly within the spirit and scope of the appended claims. All changes and modifications that fall within the scope of the claims or their equivalents are intended to be covered by the appended claims.

Claims

1. A cryogenic liquid storage and sealing device, characterized in that: include: A reservoir body buried in the soil, having an inner cavity for storing cryogenic liquid; Refrigeration system acting on the top, bottom and circumferential side walls of the warehouse; The pressure regulating system is connected to the inner cavity of the storage body and regulates the inner cavity pressure of the storage body through air pressure; Before the cryogenic liquid is injected into the inner cavity, the refrigeration system regulates the temperature distribution of the soil around the reservoir. At the same time, the pressure regulating system regulates the gas pressure in the inner cavity to allow moisture to migrate and gather in the soil to form an ice layer. Under the joint action of the refrigeration system and the pressure regulating system, the growth rate and direction of the ice layer in the soil can be controlled. The storage body is buried in modified soil with low thermal conductivity and high strength. Under the joint action of the refrigeration system and the pressure regulation system, the growth rate and direction of the ice layer in the modified soil can be controlled; A flexible enclosure structure is set up around the reservoir, and modified soil is filled in the enclosure structure. When the ice layer grows and generates pressure, the enclosure structure can allow a certain degree of slip deformation, so that the pressure can be transmitted to the critical area of ​​ice growth, ensuring the uniform growth of the ice layer; The enclosure structure includes flexible blocking members arranged at the top and bottom of the storage body, and a plurality of flexible connecting plates arranged around the storage body and extending radially toward the storage body. The diameter of the blocking members is larger than the diameter of the storage body. The connecting plates connect the flexible blocking members at the top and bottom. The adjacent connecting plates and the blocking members at the top and bottom together form a receiving tank filled with modified soil. The storage body includes an inner cavity support structure, an upper flange, a neck tube and an upper end cover. The inner cavity support structure and the upper flange are made of stainless steel to provide sufficient strength and low temperature resistance. The upper flange is arranged on the top of the inner cavity support structure, and the neck tube is sleeved with the upper flange; the upper end cover is detachably arranged at the upper end of the storage body and connected to the inner cavity through the neck tube.

2. The cryogenic liquid storage and sealing device according to claim 1, characterized in that: Modified soil is made by mixing natural soil and additives in appropriate proportions.

3. The cryogenic liquid storage and sealing device according to claim 2, characterized in that: It also includes a monitoring mechanism for monitoring the wall temperature and inner cavity pressure of the storage body. During the growth of the ice layer, the refrigerant flow and inner cavity pressure are dynamically adjusted by real-time monitoring of the wall temperature and inner cavity pressure of the storage body, so that the ice layer grows evenly and slowly in the modified soil.

4. The cryogenic liquid storage and sealing device according to claim 1, characterized in that: The refrigeration system includes a heat exchanger and a circulating refrigerator. The heat exchanger acts on the top, bottom and circumferential side walls of the storage body. The circulating refrigerator is connected to the heat exchanger pipeline and circulates the refrigerant to the heat exchanger through the pipeline.

5. The cryogenic liquid storage and sealing device according to claim 4, characterized in that: The heat exchanger includes a first heat exchanger arranged at the top of the inner cavity, a second heat exchanger arranged on the circumferential side wall of the inner cavity, and a third heat exchanger arranged at the bottom of the inner cavity. The circulating refrigerator includes a first circulating refrigerator connected to the first heat exchanger pipeline, a second circulating refrigerator connected to the second heat exchanger pipeline, and a third circulating refrigerator connected to the third heat exchanger pipeline.

6. The cryogenic liquid storage and sealing device according to claim 5, characterized in that: The neck tube is made of PTFE material. In a low temperature environment, the neck tube is locked by utilizing the shrinkage deformation of the upper flange made of stainless steel, thereby making the upper flange and the neck tube sealed and connected.

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