Liquid nitrogen pre-cooling safety device of LNG (Liquefied Natural Gas) storage tank
By using a multi-point liquid nitrogen injection system and real-time temperature monitoring, the problem of uneven cooling during the precooling process of LNG storage tanks was solved, achieving uniform cooling and stable precooling effect, thus improving safety and operational efficiency.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- GUANGHUI ENERGY COMPREHENSIVE LOGISTICS DEV CO LTD
- Filing Date
- 2025-07-11
- Publication Date
- 2026-05-19
AI Technical Summary
Existing LNG storage tanks suffer from uneven cooling during liquid nitrogen precooling, resulting in over- or under-precooling in some areas, which makes it difficult to meet the requirements for safety and efficient operation.
A multi-point liquid nitrogen injection system is adopted, which sprays liquid nitrogen evenly through a ring pipe and nozzles. Combined with a real-time temperature monitoring and control system, it ensures uniform cooling of the inner storage tank and maintains stable pressure through a venting valve.
Uniform precooling of LNG storage tanks was achieved, improving safety and operational efficiency, and ensuring the stability and precise control of the precooling process.
Smart Images
Figure CN224261450U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of LNG storage tank technology, and in particular to a safety device for liquid nitrogen precooling of LNG storage tanks. Background Technology
[0002] LNG storage tanks are specialized equipment used to store cryogenic liquefied natural gas. They play an important role in energy transportation, storage, and peak shaving. LNG is produced by purifying and cooling natural gas to approximately -162°C. It is characterized by its small size and high energy density and needs to be stored in a low-temperature, normal-pressure environment to maintain its liquid state.
[0003] LNG storage tanks use vacuum insulation or polyurethane materials to reduce the transfer of external heat and prevent LNG vaporization. In industrial applications, LNG storage tanks must meet strict safety standards to prevent the risks of low-temperature leakage and abnormal pressure. With the growth of global natural gas demand, the capacity, safety and efficient operation of LNG storage tanks have become the focus of the industry. The pre-cooling process is a key step before the tank is put into use and directly affects the subsequent storage safety and energy consumption level.
[0004] Currently, liquid nitrogen precooling technology is commonly used to reduce the temperature of LNG storage tanks before they are put into operation, in order to avoid equipment damage caused by excessive temperature difference during LNG injection. Traditional precooling methods mostly use liquid nitrogen to cool down the tank at a single point. However, due to the uneven distribution of liquid nitrogen during the transmission process, the cooling rate of different parts of the tank varies significantly. The temperature drops sharply in the area where liquid nitrogen is concentrated, while the temperature drops slowly in the area far from the injection point. This results in insufficient precooling in some areas and over-precooling in others, making it difficult for the single-point transmission method to meet the requirements of safe and efficient operation of LNG storage tanks. Utility Model Content
[0005] To overcome the above deficiencies, this utility model provides a liquid nitrogen precooling safety device for LNG storage tanks, aiming to improve the problem that the existing technology using a single-point transportation method cannot meet the requirements for safe and efficient operation of LNG storage tanks.
[0006] To achieve the above objectives, the present invention adopts the following technical solution: a liquid nitrogen precooling safety device for LNG storage tanks, comprising an insulated outer shell, a plurality of columns fixedly connected to the bottom inner side of the insulated outer shell, an inner storage tank fixedly connected to the top of each of the plurality of columns, a precooling mechanism provided inside the insulated outer shell for precooling the inner storage tank, and a monitoring mechanism provided outside the insulated outer shell for real-time temperature monitoring of the inner storage tank during precooling;
[0007] The precooling mechanism includes an input pipe and multiple annular pipes. The input pipe passes through the bottom left side of the insulation shell. A connecting pipe is provided between the multiple annular pipes, and the multiple annular pipes are connected to each other through the connecting pipes. Multiple nozzles are connected to the top of the multiple annular pipes. A precooling partition is provided between the insulation shell and the inner storage tank. A dual-channel connecting assembly is provided at the left end of the input pipe.
[0008] As a further description of the above technical solution:
[0009] The monitoring mechanism includes multiple mounting components, which are fixedly connected at equal intervals around the outer perimeter and top perimeter of the inner storage tank. Each mounting component has a temperature sensing element fixedly connected inside, and the temperature sensing elements penetrate the interior of the inner storage tank. Each temperature sensing element has a signal processing unit fixedly connected to its outer side, and a heat insulation shell is fixedly connected between the signal processing unit and the mounting component.
[0010] As a further description of the above technical solution:
[0011] The top right side of the insulation shell is connected to a venting valve, and the input end of the venting valve is connected to the pre-cooling partition.
[0012] As a further description of the above technical solution:
[0013] The dual-channel connection assembly includes a three-way pipe connected to the left end of the input pipe, and handwheels are installed on both the front and rear sides of the top of the three-way pipe.
[0014] As a further description of the above technical solution:
[0015] The dual-channel connection assembly also includes two connecting flanges, which are respectively fixedly connected to the two input ends of the tee pipe.
[0016] As a further description of the above technical solution:
[0017] Both handwheels are fixedly connected to the outside of a heat insulation sleeve, and both heat insulation sleeves are designed with anti-slip properties.
[0018] As a further description of the above technical solution:
[0019] A heat insulation pad is fixedly connected to the bottom of the heat insulation shell, and the heat insulation pad has a hollow design inside.
[0020] As a further description of the above technical solution:
[0021] The rear top of the insulation shell is connected to a material guide pipe, and the rear end of the material guide pipe is connected to the inside of the inner storage tank.
[0022] This utility model has the following beneficial effects:
[0023] 1. In this utility model, a three-way pipe is connected to an external liquid nitrogen pipeline through a connecting flange. The liquid nitrogen input is controlled by turning a handwheel. The liquid nitrogen is transported to the annular pipe through the input pipe and connecting pipe, and then sprayed into the pre-cooling partition by a nozzle. The venting valve maintains the pressure, which realizes precise control of the liquid nitrogen pre-cooling process during the installation and commissioning of the LNG storage tank, ensuring uniform cooling of the inner storage tank and completing the pre-cooling operation safely and efficiently.
[0024] 2. In this utility model, the mounting components are fixed at equal intervals around the outer perimeter and top of the inner storage tank. The temperature sensing elements fixed inside the mounting components penetrate the inner storage tank and contact the medium. The heat insulation shell isolates external temperature interference. Multiple temperature sensing elements cover key areas, which realizes accurate monitoring of the temperature distribution of the inner storage tank and timely feedback and control during liquid nitrogen precooling of the LNG storage tank. This ensures the stable operation of the signal processing unit and improves the temperature detection accuracy and precooling control efficiency. Attached Figure Description
[0025] Figure 1 This is a perspective view of a liquid nitrogen precooling safety device for an LNG storage tank proposed in this utility model;
[0026] Figure 2 This is a front view of a liquid nitrogen precooling safety device for an LNG storage tank proposed in this utility model;
[0027] Figure 3 This is a cross-sectional view of the insulation shell in an LNG storage tank liquid nitrogen precooling safety device proposed in this utility model;
[0028] Figure 4 This is a partial structural diagram of the precooling mechanism in the liquid nitrogen precooling safety device for an LNG storage tank proposed in this utility model;
[0029] Figure 5 This is a schematic diagram of the monitoring mechanism in a liquid nitrogen precooling safety device for an LNG storage tank proposed in this utility model.
[0030] Legend:
[0031] 1. Insulated outer shell; 2. Column; 3. Inner storage tank; 4. Pre-cooling mechanism; 41. Input pipe; 42. Ring pipe; 43. Connecting pipe; 44. Nozzle; 45. Pre-cooling partition; 46. Air release valve; 47. Dual-channel connection assembly; 471. T-pipe; 472. Handwheel; 473. Connecting flange; 474. Insulation sleeve; 5. Monitoring mechanism; 51. Mounting parts; 52. Temperature sensing element; 53. Signal processing unit; 54. Insulation shell; 6. Insulation pad; 7. Material guide pipe. Detailed Implementation
[0032] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.
[0033] Reference Figure 1 , Figure 3 and Figure 4 An embodiment of this utility model provides a liquid nitrogen precooling safety device for an LNG storage tank, comprising an insulated outer shell 1, a plurality of columns 2 fixedly connected to the bottom inner side of the insulated outer shell 1, an inner storage tank 3 fixedly connected to the top of each of the plurality of columns 2, a precooling mechanism 4 provided inside the insulated outer shell 1 for precooling the inner storage tank 3, and a monitoring mechanism 5 provided outside the insulated outer shell 1 for real-time temperature monitoring of the inner storage tank 3 during precooling;
[0034] The precooling mechanism 4 includes an inlet pipe 41 and multiple annular pipes 42. The inlet pipe 41 passes through the bottom left side of the insulation shell 1. A connecting pipe 43 is provided between the multiple annular pipes 42, and the multiple annular pipes 42 are connected through the connecting pipes 43. Multiple nozzles 44 are connected to the top of the multiple annular pipes 42. A precooling partition 45 is provided between the insulation shell 1 and the inner storage tank 3. A venting valve 46 is connected to the top right side of the insulation shell 1. The input end of the venting valve 46 is connected to the precooling partition 45. The left end of the inlet pipe 41 is provided with... The device is equipped with a dual-channel connection assembly 47, which includes a three-way pipe 471 connected to the left end of the input pipe 41. Handwheels 472 are installed on the front and rear sides of the top of the three-way pipe 471. The dual-channel connection assembly 47 also includes two connecting flanges 473, which are fixedly connected to the two input ends of the three-way pipe 471 respectively. Insulation sleeves 474 are fixedly connected to the outside of the two handwheels 472, and the outside of the two insulation sleeves 474 is designed to be non-slip.
[0035] Specifically, the input pipe 41 of the precooling mechanism 4 passes through the bottom left side of the insulation shell 1, and its left end is connected to the tee pipe 471. Handwheels 472 are installed on the front and rear sides of the top of the tee pipe 471, and the two input ends are fixedly connected to flanges 473 respectively. The handwheel 472 is fixed to the outside of the insulation sleeve 474. Multiple annular pipes 42 are connected through connecting pipes 43, and multiple nozzles 44 are connected to the top, which are arranged in the precooling partition 45 between the insulation shell 1 and the inner storage tank 3. The top right side of the insulation shell 1 is connected to the venting valve 46, and its input end is connected to the precooling partition 45.
[0036] The three-way pipe 471 is connected to the external liquid nitrogen delivery pipeline via the connecting flange 473. The on / off state of the three-way pipe 471 can be controlled by turning the handwheel 472. Liquid nitrogen enters the pre-cooling mechanism 4 through the input pipe 41, is distributed to multiple annular pipes 42 through the connecting pipe 43, and is then sprayed into the pre-cooling partition 45 through the nozzle 44. The spray direction of the nozzle 44 is towards the surface of the inner storage tank 3. The liquid nitrogen vaporizes and absorbs heat, reducing the temperature of the inner storage tank 3. The nitrogen in the pre-cooling partition 45 is discharged through the venting valve 46 to avoid excessive pressure.
[0037] The number and arrangement of the annular pipes 42 are designed according to the size of the inner storage tank 3 to ensure uniform precooling; the diameter of the connecting pipe 43 matches that of the input pipe 41 to ensure stable liquid nitrogen flow; the spacing of the nozzles 44 allows liquid nitrogen to uniformly cover the surface of the inner storage tank 3; the opening pressure of the venting valve 46 is set to a safe value, and it automatically opens to release pressure when the pressure inside the precooling partition 45 exceeds the set value; the insulation sleeve 474 is made of a material with good heat insulation performance to prevent operators from getting frostbite when they come into contact with the handwheel 472;
[0038] The monitoring mechanism 5 is located outside the insulation shell 1 to monitor the temperature of the inner storage tank 3 in real time during precooling. The monitoring data is fed back to the control system to adjust the liquid nitrogen input. The column 2 is fixed to the bottom inside the insulation shell 1 to support the inner storage tank 3 and ensure its position is stable during precooling. The insulation shell 1 uses multi-layer insulation material to reduce the transfer of external heat and maintain the precooling effect.
[0039] Liquid nitrogen input is controlled by the dual-channel connection component 47, and liquid nitrogen is sprayed evenly by the annular pipe 42 and the nozzle 44. The gas discharge valve 46 maintains the pressure stability of the pre-cooling partition 45. Combined with the real-time temperature monitoring of the monitoring mechanism 5, the pre-cooling of the inner storage tank 3 is safely and efficiently carried out in the LNG storage tank installation and commissioning scenario, and the pre-cooling process is stable and controllable.
[0040] Reference Figure 1 , Figure 2 and Figure 5 The monitoring mechanism 5 includes multiple mounting parts 51, which are fixedly connected at equal intervals to the outer perimeter and top perimeter of the inner storage tank 3. Each mounting part 51 has a temperature sensing element 52 fixedly connected inside, and the temperature sensing elements 52 penetrate the interior of the inner storage tank 3. Each temperature sensing element 52 has a signal processing unit 53 fixedly connected to the outside of, and a heat insulation shell 54 is fixedly connected between the signal processing unit 53 and the mounting part 51.
[0041] Specifically, the monitoring agency 5 uses temperature sensing elements 52 arranged at multiple points and a signal processing unit 53 to achieve real-time monitoring of the temperature of the inner storage tank 3;
[0042] Multiple mounting components 51 are equidistantly fixed around the outside and top of the inner storage tank 3. A temperature sensing element 52 is fixed inside the inner storage tank 3, and the temperature sensing element 52 penetrates the inside of the inner storage tank 3. A signal processing unit 53 is fixed on the outside of the inner storage tank 3. A heat insulation shell 54 is fixed between the signal processing unit 53 and the mounting components 51.
[0043] The temperature sensing element 52 directly contacts the interior of the inner storage tank 3 to sense temperature changes in real time; the signal processing unit 53 converts the temperature signal of the temperature sensing element 52 into an electrical signal and amplifies and filters it; the heat insulation shell 54 isolates external ambient temperature interference to ensure stable operation of the signal processing unit 53; the distribution of multiple temperature sensing elements 52 covers key areas of the inner storage tank 3 to comprehensively monitor temperature distribution.
[0044] The fixing method of the mounting component 51 ensures that the temperature sensing element 52 is in close contact with the inner storage tank 3, thereby improving the temperature detection accuracy; the output signal of the signal processing unit 53 is transmitted to the control system to adjust the liquid nitrogen input of the precooling mechanism 4; the material and structural design of the heat insulation shell 54 effectively reduces the impact of external heat on the signal processing unit 53.
[0045] Temperature data is collected in real time by temperature sensing element 52, signal processing unit 53 converts and processes the signal, and insulation shell 54 ensures monitoring stability, so as to achieve accurate acquisition of temperature distribution in inner tank 3 and timely feedback and control effect during liquid nitrogen precooling of LNG storage tank.
[0046] Reference Figure 2 and Figure 3 The bottom of the heat insulation shell 1 is fixedly connected to the heat insulation pad 6. The heat insulation pad 6 has a hollow design. The top rear side of the heat insulation shell 1 is connected to the guide pipe 7. The rear end of the guide pipe 7 is connected to the inside of the inner storage tank 3.
[0047] Specifically, the hollow structure of the insulation pad 6 reduces heat conduction through the bottom, reduces the impact of the external environment on the internal temperature of the insulation shell 1, and maintains the low temperature environment of the pre-cooling partition 45 and the inner storage tank 3; the feed pipe 7 serves as a material channel for conveying LNG or other media into the inner storage tank 3, and its connection position ensures that the material can smoothly enter the inner storage tank 3.
[0048] The insulation pad 6 is made of a material with low thermal conductivity, and the hollow design further enhances the insulation effect; the diameter and length of the feed pipe 7 are designed according to actual needs to ensure smooth material conveying; the connection between the feed pipe 7 and the insulation shell 1 and the inner storage tank 3 adopts a sealed structure to prevent heat transfer or material leakage.
[0049] Working principle: The insulation shell 1 serves as the external protective structure of the device. Multiple columns 2 are fixed to the bottom inside to support the inner storage tank 3 and ensure its stability during the pre-cooling process. A heat insulation pad 6 is installed at the bottom of the insulation shell 1. Its hollow design combined with a low thermal conductivity material reduces heat conduction to the interior of the insulation shell 1 through the bottom, maintaining the low temperature environment inside. The top rear side of the insulation shell 1 is connected to a material guide pipe 7, which is used to transport LNG or other media to the inner storage tank 3. The connection between the material guide pipe 7 and the insulation shell 1 and the inner storage tank 3 adopts a sealed structure to prevent heat transfer and material leakage.
[0050] The precooling mechanism 4 is located between the insulation shell 1 and the inner storage tank 3. The input pipe 41 passes through the bottom left side of the insulation shell 1, and its left end is connected to the external liquid nitrogen delivery pipeline through the dual-channel connection assembly 47. Handwheels 472 are installed on the front and rear sides of the top of the tee pipe 471 of the dual-channel connection assembly 47, and an insulation sleeve 474 is installed on the outside. The two input ends are connected to the pipeline through the connecting flange 473. Turning the handwheel 472 can control the opening and closing of the tee pipe 471 to realize the liquid nitrogen input control. Multiple annular pipes 42 are connected to the connecting pipe 4. 3 are interconnected, with multiple nozzles 44 installed at the top and distributed within the pre-cooling partition 45; liquid nitrogen enters through the input pipe 41, is distributed to the annular pipe 42 through the connecting pipe 43, and is then sprayed into the pre-cooling partition 45 by the nozzles 44; the nozzles 44 spray liquid nitrogen toward the surface of the inner storage tank 3, the liquid nitrogen vaporizes and absorbs heat, reducing the temperature of the inner storage tank 3; the nitrogen gas generated in the pre-cooling partition 45 is discharged through the venting valve 46 on the right side of the top of the insulation shell 1, the venting valve 46 is set with a safe opening pressure, and automatically depressurizes when the pressure in the pre-cooling partition 45 exceeds the limit;
[0051] The monitoring mechanism 5 is distributed outside the inner storage tank 3. Multiple mounting components 51 are equidistantly fixed around and on top of the inner storage tank 3. Temperature sensing elements 52 are fixed inside the mounting components 51. The temperature sensing elements 52 penetrate the interior of the inner storage tank 3 and directly contact the medium inside the inner storage tank 3 to sense temperature changes in real time. A signal processing unit 53 is fixed outside the temperature sensing element 52 to convert the temperature signal into an electrical signal and perform amplification and filtering. A heat insulation shell 54 is set between the signal processing unit 53 and the mounting components 51 to reduce the interference of the external ambient temperature on the signal processing unit 53. The distribution of multiple temperature sensing elements 52 covers the key areas of the inner storage tank 3 to comprehensively monitor the temperature distribution. The signal processing unit 53 outputs a signal to the control system to adjust the liquid nitrogen input of the pre-cooling mechanism 4 according to the temperature data.
[0052] In the actual precooling process, the external liquid nitrogen pipeline is first connected to the input pipe 41 through the dual-channel connection component 47. The handwheel 472 is turned to open the three-way pipe 471, and liquid nitrogen enters the precooling mechanism 4. The liquid nitrogen is evenly sprayed onto the precooling partition 45 through the annular pipe 42 and the nozzle 44 to cool the inner storage tank 3. At the same time, the temperature sensing element 52 of the monitoring mechanism 5 collects the temperature data of the inner storage tank 3 in real time. The signal processing unit 53 processes the data and feeds it back to the control system. If the temperature does not reach the expected level, the control system adjusts the handwheel 472 to control the liquid nitrogen input. During the precooling process, when the pressure inside the precooling partition 45 rises, the venting valve 46 automatically opens to release the gas. After the precooling of the inner storage tank 3 is completed, the handwheel 472 is closed to stop the liquid nitrogen input. LNG or other media are then transported to the inner storage tank 3 through the feed pipe 7.
[0053] Finally, it should be noted that the above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Although the present utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.
Claims
1. A liquid nitrogen precooling safety device for an LNG storage tank, comprising an insulated outer shell (1), characterized in that: Multiple columns (2) are fixedly connected to the bottom inner side of the heat-insulating shell (1), and an inner storage tank (3) is fixedly connected to the top of each of the multiple columns (2). A pre-cooling mechanism (4) is provided inside the heat-insulating shell (1), which is used to pre-cool the inner storage tank (3). A monitoring mechanism (5) is provided outside the heat-insulating shell (1), which is used to monitor the temperature of the inner storage tank (3) in real time during pre-cooling. The precooling mechanism (4) includes an input pipe (41) and multiple annular pipes (42). The input pipe (41) passes through the bottom left side of the insulation shell (1). A connecting pipe (43) is provided between the multiple annular pipes (42). The multiple annular pipes (42) are connected through the connecting pipe (43). Multiple nozzles (44) are connected to the top of the multiple annular pipes (42). A precooling partition (45) is provided between the insulation shell (1) and the inner storage tank (3). A dual-channel connecting assembly (47) is provided at the left end of the input pipe (41).
2. The LNG storage tank liquid nitrogen precooling safety device according to claim 1, characterized in that: The monitoring mechanism (5) includes multiple mounting components (51), which are fixedly connected at equal intervals to the outer periphery and top periphery of the inner storage tank (3). Each mounting component (51) has a temperature sensing element (52) fixedly connected inside, and the temperature sensing elements (52) penetrate the interior of the inner storage tank (3). Each temperature sensing element (52) has a signal processing unit (53) fixedly connected to the outer side, and a heat insulation shell (54) is fixedly connected between the signal processing unit (53) and the mounting component (51).
3. The LNG storage tank liquid nitrogen precooling safety device according to claim 1, characterized in that: The top right side of the heat-insulating shell (1) is connected to a venting valve (46), and the input end of the venting valve (46) is connected to the pre-cooling partition (45).
4. The LNG storage tank liquid nitrogen precooling safety device according to claim 1, characterized in that: The dual-channel connection assembly (47) includes a three-way pipe (471) connected to the left end of the input pipe (41), and a handwheel (472) is installed on both the front and rear sides of the top of the three-way pipe (471).
5. The LNG storage tank liquid nitrogen precooling safety device according to claim 1, characterized in that: The dual-channel connection assembly (47) also includes two connection flanges (473), which are respectively fixedly connected to the two input ends of the tee pipe (471).
6. The LNG storage tank liquid nitrogen precooling safety device according to claim 4, characterized in that: Both handwheels (472) are fixedly connected to the outside of a heat insulation sleeve (474), and the outside of both heat insulation sleeves (474) is designed to be non-slip.
7. The LNG storage tank liquid nitrogen precooling safety device according to claim 1, characterized in that: The bottom of the heat-insulating shell (1) is fixedly connected to a heat-insulating pad (6), and the interior of the heat-insulating pad (6) is hollow.
8. The LNG storage tank liquid nitrogen precooling safety device according to claim 1, characterized in that: The rear top of the heat-insulating shell (1) is connected to a material guide pipe (7), and the rear end of the material guide pipe (7) is connected to the interior of the inner storage tank (3).