LNG storage tanks and LNG carriers

Abstract

This invention provides an LNG storage tank and an LNG carrier for storing LNG fuel. The LNG storage tank has an external conduit for absorbing heat from the surrounding environment. The conduit is connected to an outlet circulation pipe and an outlet pipe. The outlet circulation pipe connects to the inside of the LNG storage tank, allowing the conduit to receive LNG fuel. The conduit absorbs ambient heat, converting the LNG fuel into gaseous natural gas, which is then output through the outlet pipe. This invention, by placing the conduit outside the LNG storage tank, absorbs heat from the external environment, causing the LNG fuel to gradually vaporize, thus reducing the need for heat exchangers and achieving energy savings. Simultaneously, the conduit absorbs ambient heat outside the LNG storage tank, cooling the surrounding environment and reducing heat exchange between the inside and outside of the tank, thereby extending the storage time of liquefied natural gas.

Description

Technical Field

[0001] This invention relates to the field of liquefied natural gas storage tank technology, specifically to LNG storage tanks and LNG ships. Background Technology

[0002] Liquefied Natural Gas (LNG) is natural gas that has been compressed and cooled to its freezing point (-161.5°C), turning it into a liquid. LNG is typically stored in cryogenic tanks at approximately -161.5°C and 0.1 MPa. Large gas-consuming equipment, such as natural gas-powered ships, usually requires LNG storage tanks. Due to current limitations in insulation materials and manufacturing processes, heat absorbed from the environment gradually transfers into the LNG storage tank, heating the liquefied natural gas inside. This causes the LNG to gradually vaporize, increasing the pressure within the tank and reducing its storage time. Improper handling can easily lead to safety hazards.

[0003] Meanwhile, in the process of using liquefied natural gas (LNG), the liquefied natural gas needs to be converted into gaseous natural gas for users to burn. This process requires heat exchangers, and because the heat exchangers need to absorb a large amount of heat, a high-power heat source is typically required. Summary of the Invention

[0004] To address the aforementioned shortcomings, the present invention aims to provide an LNG storage tank and LNG vessel that, by vaporizing natural gas outside the LNG storage tank, reduces the temperature around the LNG storage tank, slows down the evaporation rate inside the LNG storage tank, saves cooling energy, and extends the storage time of liquefied natural gas inside the tank.

[0005] This invention provides an LNG storage tank for storing LNG fuel. The LNG storage tank is externally equipped with a flow guide pipe for absorbing heat from the surrounding environment. The flow guide pipe is connected to an outlet circulation pipe and an output pipe. The outlet circulation pipe is connected to the inside of the LNG storage tank so that the flow guide pipe receives LNG fuel. The flow guide pipe absorbs ambient heat to convert the LNG fuel into gaseous natural gas, which is then output through the output pipe.

[0006] Furthermore, the outer wall of the LNG storage tank is provided with multiple sets of the flow guide pipes, and the liquid outlet circulation pipe is equipped with multiple switching valves to control the flow rate of the liquid outlet circulation pipe through each of the switching valves.

[0007] Furthermore, a controller is also installed outside the LNG storage tank, and the controller is electrically connected to the switching valve.

[0008] Furthermore, the liquid outlet circulation pipe includes a first liquid outlet circulation branch pipe, a second liquid outlet circulation branch pipe, a third liquid outlet circulation branch pipe, and a main liquid outlet pipe; the switching valve includes a first switching valve, a second switching valve, and a third switching valve; the first liquid outlet circulation branch pipe is equipped with the first switching valve, the second liquid outlet circulation branch pipe is equipped with the second switching valve, and the third liquid outlet circulation branch pipe is equipped with the third switching valve; the main pipe extends to the LNG tank to obtain LNG fuel.

[0009] Furthermore, the guide tube includes a first guide tube branch, a second guide tube branch, and a third guide tube branch. The first guide tube branch is connected to the first liquid outlet circulation branch; the second guide tube branch is connected to the second liquid outlet circulation branch; and the third guide tube branch is connected to the third liquid outlet circulation branch.

[0010] Furthermore, the first input end and the first output end of the first diversion branch are both located at the upper part of the LNG storage tank; the second input end of the second diversion branch is located at the right side of the LNG storage tank, and the second output end of the second diversion branch is located at the left side of the LNG storage tank; the third input end and the third output end of the third diversion branch are both located at the bottom of the LNG storage tank.

[0011] Furthermore, the LNG storage tank is also equipped with an internal temperature sensor for monitoring the inside of the LNG storage tank and an ambient temperature sensor for monitoring the outside of the LNG storage tank. Both the internal temperature sensor and the ambient temperature sensor are electrically connected to the controller.

[0012] Furthermore, a pressure regulating valve is also configured on the outside of the LNG storage tank, and the pressure regulating valve is connected to the output pipe and the inside of the LNG storage tank respectively; the pressure regulating valve is also electrically connected to the controller.

[0013] Furthermore, a vacuum insulation layer is provided between the inner and outer walls of the LNG storage tank.

[0014] The present invention also provides an LNG carrier, including the above-mentioned LNG storage tank.

[0015] The LNG storage tank and LNG carrier provided in this embodiment have the following advantages:

[0016] (1) The guide pipe is set outside the LNG storage tank. By absorbing the heat of the external environment, the LNG fuel is vaporized into gaseous natural gas, thereby reducing the use of heat exchangers and achieving the purpose of energy saving;

[0017] (2) By absorbing heat from the environment outside the LNG storage tank through the diversion pipe, the environment around the LNG storage tank is cooled, thereby reducing heat exchange between the inside and outside of the storage tank and extending the storage time of liquefied natural gas.

[0018] (3) Automatically collect temperature data inside and outside the LNG storage tank and feed it back to the controller. The controller controls the number of valves to open, so as to automatically stabilize the pressure of the output pipeline and eliminate the influence of atmospheric temperature changes. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the LNG storage tank in an embodiment of the present invention.

[0021] In the diagram, 10-flow guide pipe, 11-first flow guide branch pipe, 111-first input end, 112-first output end, 12-second flow guide branch pipe, 121-second input end, 122-second output end, 13-third flow guide branch pipe, 131-third input end, 132-third output end, 20-liquid outlet circulation pipe, 21-first circulation pipe assembly, 22-second circulation pipe assembly, 23-third circulation pipe assembly, 24-liquid outlet main pipe, 30-output pipe, 41-first switching valve, 42-second switching valve, 43-third switching valve, 51-internal temperature sensor, 52-ambient temperature sensor, 60-controller, 70-pressure regulating valve, 80-vacuum insulation layer. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] The directional terms such as "up," "down," "left," "right," "front," "back," "top," and "bottom" (if present) used in the specification and claims of this invention are defined by the position of the structures in the drawings and the relative positions of the structures, and are only for the clarity and convenience of expressing the technical solution. It should be understood that the use of directional terms should not limit the scope of protection claimed in this application.

[0024] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0025] Please see Figure 1 This invention provides an LNG storage tank for storing LNG fuel. The LNG storage tank has an external guide pipe 10 for absorbing heat from the surrounding environment. The guide pipe 10 is connected to an outlet circulation pipe 20 and an outlet pipe 30. The outlet circulation pipe 20 is connected inside the LNG storage tank so that the guide pipe 10 receives LNG fuel. The LNG fuel absorbs ambient heat through the guide pipe 10, converting it into gaseous natural gas, which is then output through the outlet pipe 30 for user use. Notably, the guide pipe 10 can be installed flush with the outer wall of the LNG storage tank or at a certain distance. The guide pipe 10 can be installed in a single layer or in multiple layers around the outside of the LNG storage tank. The guide pipe 10 can be arranged in a serpentine pattern around the outside of the LNG storage tank or can be arranged to wrap around the outer wall of the tank to ensure sufficient heat exchange area; this application does not limit this arrangement.

[0026] Specifically, the LNG storage tank is equipped with multiple sets of guide pipes 10 on the outside, and the liquid outlet circulation pipe 20 is equipped with multiple switching valves to control the flow rate of the liquid outlet circulation pipe 20. The multiple sets of guide pipes 10 are evenly distributed along the side wall of the LNG storage tank. Different numbers of guide pipes 10 can be activated by switching valves according to the external ambient temperature to stabilize the output pipe 30 and overcome the influence of the external ambient temperature.

[0027] The LNG storage tank is also equipped with a controller 60, which is electrically connected to the switching valve. The controller 60 can automatically control the switching valve to achieve automatic control and reduce the need for manual labor.

[0028] Specifically, the liquid outlet circulation pipe 20 includes a first liquid outlet circulation branch pipe 21, a second liquid outlet circulation branch pipe 22, a third liquid outlet circulation branch pipe 23, and a main liquid outlet pipe 24. The switching valves include a first switching valve 41, a second switching valve 42, and a third switching valve 43. The first liquid outlet circulation branch pipe 21 is equipped with the first switching valve 41, the second liquid outlet circulation branch pipe 22 is equipped with the second switching valve 42, and the third liquid outlet circulation branch pipe 23 is equipped with the third switching valve 43. The main pipe 24 extends to the LNG tank, obtains LNG fuel from inside the LNG storage tank, and delivers it to the first liquid outlet circulation branch pipe 21, the second liquid outlet circulation branch pipe 22, and the third liquid outlet circulation branch pipe 23, respectively, and controls the output through the first switching valve 41, the second switching valve 42, and the third switching valve 43, respectively.

[0029] The guide pipe 10 includes a first guide pipe branch 11, a second guide pipe branch 12, and a third guide pipe branch 13. The first guide pipe branch 11 is connected to the first liquid outlet circulation branch 21, the second guide pipe branch 12 is connected to the second liquid outlet circulation branch 22, and the third guide pipe branch 13 is connected to the third liquid outlet circulation branch 23.

[0030] The first input end 111 and the first output end 112 of the first diversion branch pipe 11 are both located at the top of the LNG storage tank; the second input end 121 of the second diversion branch pipe 12 is located on the right side of the LNG storage tank, and the second output end 122 of the second diversion branch pipe 12 is located on the left side of the LNG storage tank; the third input end 131 and the third output end 132 of the third diversion branch pipe 13 are both located at the bottom of the LNG storage tank.

[0031] As an optional embodiment in this example, the first guide branch pipe 11 has two first input ends 111 and one first output end 112. The first liquid outlet circulation branch pipe 21 is connected to the two first input ends 111 respectively to transport LNG fuel to the first guide branch pipe through the two first input ends 111. The first output end 112 is located on the top left side of the LNG storage tank for easy connection to the output pipe 30. In actual use, the first guide branch pipe 11 obtains LNG fuel from the two first input ends 111 respectively. The LNG fuel absorbs heat from the external environment of the first guide branch pipe 11 as it travels a predetermined length, causing the LNG fuel to gradually vaporize. The second guide branch pipe 12 is provided with only one second input end 121 and one second output end 122. To facilitate connection with the second liquid outlet circulation branch pipe 22 and subsequent connection to the output pipe 30, the second output end 122 is located on the left side of the LNG storage tank, and the second input end 121 is located on the right side of the LNG storage tank. The second guide branch 12 receives LNG fuel from the second outlet circulation branch 22 at the second input end 121. After passing through a predetermined length, the LNG gas is gradually vaporized, and the vaporized natural gas is output from the second output end 122 to the output pipe 30. The third guide branch 13 is also provided with two third input ends 131 and one third output end 132. Its principle is the same as that of the first guide branch 11, and will not be described again here.

[0032] The length of the guide pipe 10 is set according to the actual situation. The increased length of the guide pipe 10 is set along the outside of the LNG storage tank, which ensures the heat exchange length for LNG fuel gasification and at the same time provides a better cooling effect around the LNG storage tank.

[0033] The LNG storage tank is equipped with an internal temperature sensor 51 for monitoring the temperature inside the tank and an ambient temperature sensor 52 for monitoring the ambient temperature outside the tank. Both the internal temperature sensor 51 and the ambient temperature sensor 52 are electrically connected to the controller 60. The controller 60 collects data from the internal temperature sensor 51 and the ambient temperature sensor 52, and controls the number of valves to be opened based on a preset threshold for the temperature difference between the two sensors. Since ambient temperature fluctuates, such as due to solar radiation, the ambient temperature during the day is higher than at night. When the internal temperature sensor 51 and the ambient temperature sensor 52 detect a large temperature difference, the number of valves opened is appropriately reduced; when the temperature difference is small, the number of valves opened is appropriately increased. By controlling the number of valves opened, the pressure in the gas outlet pipe 30 is stabilized, thus eliminating the adverse effects of atmospheric temperature changes on the invention.

[0034] In this embodiment, three sets of switching valves are provided: a first switching valve 41, a second switching valve 42, and a third switching valve 43. The user can preset 3-7 differential threshold values. For example, the first switching valve 41, the second switching valve 42, and the third switching valve 43 can be opened in odd numbers, or two of the switching valves can be opened in combination, or all three switching valves can be opened simultaneously. The threshold values ​​can be set according to actual usage and are not limited here.

[0035] To ensure a certain pressure inside the LNG storage tank, a pressure regulating valve 70 is installed outside the LNG storage tank. The pressure regulating valve 70 is connected to the output pipe 30 and the inside of the LNG storage tank. When the pressure regulating valve 70 detects that the pressure inside the LNG storage tank is too low, the natural gas in the output pipe 30 can be transported back to the LNG storage tank by adjusting the pressure regulating valve 70, thereby increasing the pressure inside the LNG storage tank.

[0036] The pressure regulating valve 70 can be an internal pressure regulating valve with a sensor and a microprocessor. The pressure regulating valve 70 is electrically connected to the controller 60. The pressure value inside the LNG storage tank collected by the pressure regulating valve 70 is fed back to the controller 60, and the controller 60 controls the opening degree of the pressure regulating valve 70.

[0037] A vacuum insulation layer 80 is installed between the inner and outer walls of the LNG storage tank. The vacuum insulation layer 80 is used to isolate the LNG fuel inside the LNG storage tank from the heat conduction between the LNG fuel and the external environment, which can reduce the loss of internal temperature of the LNG storage tank.

[0038] The present invention also provides an LNG carrier, including the above-mentioned LNG storage tank.

[0039] The working principle and process of this invention are as follows:

[0040] 1. The controller 60 is connected to a switching valve, an internal temperature sensor 51, an ambient temperature sensor 52, and a pressure regulating valve 70. By collecting the temperature of the inside and outside environment of the LNG storage tank, the controller 60 automatically opens or closes the switching valve and the pressure regulating valve 70 to achieve automatic regulation and reduce the use of manpower.

[0041] 2. LNG fuel with a temperature range of -163℃ to -140℃ is stored in the LNG storage tank. When natural gas fuel is needed, the number of valves to be opened is determined by collecting data from the internal temperature sensor 51 and the ambient temperature sensor 52. LNG fuel flows out through the outlet circulation pipe 20 and first flows into the guide pipe 10 outside the storage tank. The pressure regulating valve 70 determines the pressure inside the LNG storage tank. By opening the pressure regulating valve 70, the natural gas in the output pipe 30 can be transported back into the LNG storage tank to increase the pressure inside the LNG storage tank.

[0042] 3. Multiple sets of guide pipes 10 are arranged around the outer wall of the LNG storage tank to ensure sufficient heat exchange length with the atmosphere. LNG fuel absorbs heat from the atmosphere and the outside of the storage tank through the guide pipes 10, causing the LNG fuel to gradually vaporize. During the vaporization process, the guide pipes 10 absorb heat, reducing the temperature around the LNG storage tank, slowing down the evaporation rate of liquefied natural gas inside the tank, saving cooling energy, and extending the storage time of liquefied natural gas in the tank.

[0043] 4. Depending on the degree of natural gas vaporization, an external heat exchanger is configured at the end of the output pipe 30. Since the gas is vaporized through the guide pipe 10, the power of the external heat exchanger can be reduced. In fact, the external heat exchanger can be eliminated when the external ambient temperature is high or the solar radiation is strong, thereby achieving the purpose of energy saving.

[0044] Understandably, the present invention provides an LNG storage tank and an LNG carrier. The LNG storage tank is externally equipped with a guide pipe 10 for absorbing heat from the surrounding environment. The guide pipe 10 is connected to an outlet circulation pipe 20 and an outlet pipe 30. The outlet circulation pipe 20 is connected inside the LNG storage tank so that the guide pipe 10 receives LNG fuel. The LNG fuel absorbs ambient heat through the guide pipe 10, converting the LNG fuel into gaseous natural gas, which is then output through the outlet pipe 30 for user use. As the LNG fuel flows out through the guide pipe 10, it absorbs external heat during the vaporization process, gradually cooling the exterior of the LNG storage tank and its surrounding environment. This reduces heat exchange between the inside and outside of the LNG storage tank, saves cooling energy, and extends the storage time of liquefied natural gas.

[0045] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An LNG storage tank for storing LNG fuel, characterized in that, The LNG storage tank is provided with a flow guide pipe (10) for absorbing heat from the surrounding environment. The flow guide pipe (10) is arranged around the outside of the LNG storage tank. The flow guide pipe (10) is connected to an outlet circulation pipe (20) and an output pipe (30). The outlet circulation pipe (20) is connected to the inside of the LNG storage tank so that the flow guide pipe (10) can obtain LNG fuel. The flow guide pipe (10) absorbs ambient heat to convert LNG fuel into gaseous natural gas, which is then output through the output pipe (30). The outer wall of the LNG storage tank is provided with multiple sets of the guide pipes (10), and the liquid outlet circulation pipe (20) is equipped with multiple switching valves to control the flow rate of the liquid outlet circulation pipe (20) through each of the switching valves. The LNG storage tank is also equipped with a controller (60), which is electrically connected to the switching valve; The liquid outlet circulation pipe (20) includes a first liquid outlet circulation branch pipe (21), a second liquid outlet circulation branch pipe (22), a third liquid outlet circulation branch pipe (23), and a main liquid outlet pipe (24). The switching valves include a first switching valve (41), a second switching valve (42), and a third switching valve (43). The first liquid outlet circulation branch pipe (21) is equipped with the first switching valve (41), the second liquid outlet circulation branch pipe (22) is equipped with the second switching valve (42), and the third liquid outlet circulation branch pipe (23) is equipped with the third switching valve (43). The main pipe (24) extends to the LNG tank to obtain LNG fuel. The guide pipe (10) includes a first guide pipe branch (11), a second guide pipe branch (12), and a third guide pipe branch (13). The first guide pipe branch (11) is connected to the first liquid outlet circulation branch (21); the second guide pipe branch (12) is connected to the second liquid outlet circulation branch (22); and the third guide pipe branch (13) is connected to the third liquid outlet circulation branch (23). The first input end (111) and the first output end (112) of the first diversion branch pipe (11) are both located at the upper part of the LNG storage tank; the second input end (121) of the second diversion branch pipe (12) is located on the right side of the LNG storage tank, and the second output end (122) of the second diversion branch pipe (12) is located on the left side of the LNG storage tank; the third input end (131) and the third output end (132) of the third diversion branch pipe (13) are both located at the bottom of the LNG storage tank; The LNG storage tank is also equipped with an internal temperature sensor (51) for monitoring the inside of the LNG storage tank and an ambient temperature sensor (52) for monitoring the outside of the LNG storage tank. Both the internal temperature sensor (51) and the ambient temperature sensor (52) are electrically connected to the controller (60).

2. The LNG storage tank according to claim 1, characterized in that, The LNG storage tank is also equipped with a pressure regulating valve (70), which is connected to the output pipe (30) and the inside of the LNG storage tank respectively; the pressure regulating valve (70) is also electrically connected to the controller (60).

3. The LNG storage tank according to claim 1, characterized in that, A vacuum insulation layer (80) is provided between the inner and outer walls of the LNG storage tank.

4. An LNG carrier, characterized in that, Including LNG storage tanks as described in any one of claims 1-3.

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