System for preventing surface of LNG (liquefied natural gas) tank from condensing water and freezing

Abstract

The invention relates to the technical field of ships, in particular to a system for preventing the surface of an LNG (Liquefied Natural Gas) tank from being condensed and frozen, which comprises an air compressor, one end of the air dryer is communicated with the air compressor; the air dryer is communicated with the air bottle; one end of the pressurizing pipeline is communicated with the air bottle, the other end of the pressurizing pipeline is communicated with a storage cabin provided with an LNG tank, and a pressurizing valve is arranged on the pressurizing pipeline; the flow regulating valve is arranged on the pressurizing pipeline, and the flow regulating valve is positioned between the pressurizing valve and the storage cabin; and the pressure difference sensor is arranged in the storage cabin, the pressure difference sensor is electrically connected with the flow regulating valve, and the pressure difference sensor can control the opening degree of the flow regulating valve. The surface of the LNG tank can be prevented from being condensed and frozen, and insulation failure of the LNG tank is avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of ships, and in particular to a system for preventing condensation and icing on the surface of an LNG tank. Background Art

[0002] With the increasingly strict requirements for ship emissions, more and more ships choose LNG as a clean energy source. There are various types of LNG storage tanks, such as Type A, Type B, Type C tanks and membrane tanks. Among them, Type C tanks, as storage tanks that do not require shielding protection, are widely used. Depending on the ship type, Type C tanks can be arranged on the deck surface or in the storage tank of the LNG tank under the main deck. For ships equipped with LNG tanks in the storage tank, mechanical ventilation is designed to ensure that the storage tank has a ventilation rate of two air changes per hour.

[0003] However, due to the high humidity of the sea air, the humid air enters the storage tank of the LNG tank through the ventilation pipeline. After the LNG tank is filled with LNG, the surface temperature is lower than 0°C, and the humid air will freeze on the surface of the LNG tank. Over time, it may damage the insulation of the LNG tank, resulting in the failure of the LNG tank insulation.

[0004] Therefore, a system for preventing condensation and icing on the surface of an LNG tank is needed to solve the above problems. Summary of the Invention

[0005] The purpose of the present invention is to provide a system for preventing condensation and icing on the surface of an LNG tank, which can avoid condensation and icing on the surface of the LNG tank and prevent the failure of the LNG tank insulation.

[0006] To achieve this purpose, the present invention adopts the following technical solutions:

[0007] A system for preventing condensation and icing on the surface of an LNG tank, comprising:

[0008] An air compressor;

[0009] An air dryer, one end of which is connected to the air compressor;

[0010] An air bottle, the air dryer is connected to the air bottle;

[0011] A pressurization pipeline, one end of which is connected to the air bottle, and the other end of the pressurization pipeline is connected to the storage tank where the LNG tank is arranged. A pressure increasing valve is provided on the pressurization pipeline;

[0012] A flow regulating valve, which is provided on the pressurization pipeline and is located between the pressure increasing valve and the storage tank;

[0013] A differential pressure sensor is provided in the storage tank, and the differential pressure sensor is electrically connected to the flow regulating valve. The differential pressure sensor can control the opening degree of the flow regulating valve.

[0014] In some embodiments, a first breather pipe is further included. One end of the first breather pipe is communicated with the storage tank, and a breathing valve is arranged on the first breather pipe.

[0015] In some embodiments, a standby inflation assembly is further included. The standby inflation assembly includes an emergency inflation pipe. One end of the emergency inflation pipe is communicated with the storage tank, and an emergency breathing cut-off valve is arranged on the emergency inflation pipe.

[0016] In some embodiments, a natural gas probe and an oxygen content probe are arranged in the storage tank. The natural gas probe is used to detect the natural gas in the storage tank, and the oxygen content probe is used to detect the oxygen in the storage tank.

[0017] In some embodiments, a safety pipeline is further included. One end of the safety pipeline is communicated with the outlet of the booster valve, and a first safety valve is arranged on the safety pipeline.

[0018] In some embodiments, a second breather pipe is further included. One end of the second breather pipe is communicated with the air bottle, and a second safety valve is arranged on the second breather pipe.

[0019] In some embodiments, a nitrogen processing assembly is further included. The nitrogen processing assembly includes a nitrogen generator and a nitrogen bottle which are communicated with each other, and the nitrogen generator is communicated with the air bottle.

[0020] In some embodiments, a third breather pipe is further included. One end of the third breather pipe is communicated with the nitrogen bottle, and a third safety valve is arranged on the third breather pipe.

[0021] In some embodiments, a discharge pipeline is further included. One end of the discharge pipeline is communicated with the nitrogen bottle, and a discharge switch valve is arranged on the discharge pipeline.

[0022] In some embodiments, a fourth breather pipe is further included. One end of the fourth breather pipe is communicated with the nitrogen generator, and a fourth safety valve is arranged on the fourth breather pipe.

[0023] Advantages of the present invention:

[0024] A system for preventing condensation and icing on the surface of an LNG tank provided by the present invention includes an air compressor, an air dryer, an air bottle, and a pressurized pipeline that are connected in sequence. A pressure booster valve and a flow regulating valve are provided on the pressurized pipeline. A differential pressure sensor is provided in the storage tank. The differential pressure sensor is used to detect the pressure difference between the inside and outside of the storage tank and control the opening degree of the flow regulating valve, so that the gas pressure in the storage tank can be greater than the external gas pressure, preventing untreated external gas from directly entering the storage tank. In the above manner, after the air compressor compresses the gas, it is dried by the air dryer and stored in the air bottle. The dried gas is further pressurized by the pressure booster valve on the pressurized pipeline and then enters the storage tank through the flow regulating valve. Since there is no moisture in the gas, condensation and icing on the surface of the LNG tank are avoided, and insulation failure of the LNG tank is avoided. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments of the present invention. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained according to the content of the embodiments of the present invention and these drawings.

[0026] Figure 1 It is a schematic diagram of a system for preventing condensation and icing on the surface of an LNG tank according to the present invention.

[0027] In the figure:

[0028] 1. Air compressor; 2. Air dryer; 3. Air bottle; 31. Second air vent pipe; 32. Second safety valve; 4. Pressure booster valve; 41. Safety pipeline; 42. First safety valve; 5. Flow regulating valve; 6. Differential pressure sensor; 7. Storage tank; 71. Natural gas probe; 72. Oxygen content probe; 73. First air vent pipe; 74. Breather valve; 75. Emergency charging pipe; 76. Emergency air vent cut-off valve; 8. Nitrogen generator; 81. Fourth air vent pipe; 9. Nitrogen bottle; 91. Third air vent pipe; 92. Third safety valve; 93. Relief pipeline; 94. Relief switch valve. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0029] Before explaining any embodiment of the present application in detail, it should be understood that the present application is not limited to the structural details and component arrangements described in the following description or shown in the above drawings.

[0030] In this application, the terms "comprise", "include", "have" or any other variants thereof are intended to cover non-exclusive inclusion, such that a process, method, article or device comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising one..." does not exclude the presence of additional identical elements in the process, method, article or device comprising that element.

[0031] In this application, the terms "connect", "combine", "couple", "mount" can be direct connection, combination, coupling or mounting, or can be indirect connection, combination, coupling or mounting. Among them, for example, direct connection means that two parts or components are connected together without setting intermediate parts, and indirect connection means that two parts or components are respectively connected to at least one intermediate part, and these two parts or components are connected through the intermediate part. In addition, "connect" and "couple" are not limited to physical or mechanical connection or coupling, and can include electrical connection or coupling.

[0032] In this application, those of ordinary skill in the art will understand that the functions performed by components can be performed by one component, multiple components, one part, or multiple parts. Similarly, the functions performed by parts can also be performed by one part, one component, or a combination of multiple parts.

[0033] In this application, the orientation terms such as "upper", "lower", "left", "right", "front", "rear", etc. are described based on the orientation and positional relationship shown in the drawings, and should not be construed as a limitation on the embodiments of this application. In addition, in the context, it should also be understood that when it is mentioned that one element is connected "above" or "below" another element, it can not only be directly connected "above" or "below" another element, but also be indirectly connected "above" or "below" another element through an intermediate element. It should also be understood that orientation terms such as upper side, lower side, left side, right side, front side, rear side, etc. not only represent the positive orientation, but can also be understood as the side orientation. For example, the lower side can include directly below, lower left, lower right, lower front, and lower rear, etc.

[0034] When a ship using LNG (liquefied natural gas) as fuel is in operation, in order to avoid condensation and icing on the surface of the LNG tank, thereby avoiding insulation failure of the LNG tank, as Figure 1 shown, the present invention provides a system for preventing condensation and icing on the surface of the LNG tank. The system for preventing condensation and icing on the surface of the LNG tank includes an air compressor 1, an air dryer 2, an air bottle 3, a pressurized pipeline, a flow regulating valve 5, and a differential pressure sensor 6.

[0035] Among them, one end of the air dryer 2 is connected to the air compressor 1, and the air dryer 2 is connected to the air bottle 3. One end of the pressurization pipeline is connected to the air bottle 3, and the other end of the pressurization pipeline is connected to the storage tank 7 where the LNG tank is arranged. A pressurization valve 4 is provided on the pressurization pipeline. A flow regulating valve 5 is provided on the pressurization pipeline, and the flow regulating valve 5 is located between the pressurization valve 4 and the storage tank 7. A differential pressure sensor 6 is provided in the storage tank 7, and the differential pressure sensor 6 is electrically connected to the flow regulating valve 5. The differential pressure sensor 6 can control the opening degree of the flow regulating valve 5.

[0036] In the above manner, after the air compressor 1 compresses the gas, it is dried by the air dryer 2 and stored in the air bottle 3. After the dried gas further increases the pressure through the pressurization valve 4 on the pressurization pipeline, it enters the storage tank 7 through the flow regulating valve 5. Since there is no moisture in the gas, condensation and icing on the surface of the LNG tank are avoided, and insulation failure of the LNG tank is avoided.

[0037] In some embodiments, the air compressor 1 pressurizes the air to 8 bar, then dries it through the air dryer 2 and stores it in the air bottle 3. The compressed air in the air bottle 3 is pressurized to 1.02 bar through the pressurization valve 4, and then is transported to the storage tank 7 through the flow regulating valve 5. The flow regulating valve 5 adjusts the opening degree of the flow regulating valve 5 through the differential pressure sensor 6 provided in the storage tank 7 to ensure that the pressure in the storage tank 7 is always greater than the outside by about 50 Pa, so as to prevent the outside air from directly entering the storage tank 7.

[0038] In some embodiments, the system for preventing condensation and icing on the surface of the LNG tank further includes a first breather pipe 73. One end of the first breather pipe 73 is connected to the storage tank 7, and a breather valve 74 is provided on the first breather pipe 73. Through the above settings, overpressure of the storage tank 7 can be avoided, and deformation and damage of the cabin can be prevented. The breather valve 74 can automatically adjust the air pressure in the storage tank 7 and will not overpressure.

[0039] In some embodiments, the system for preventing condensation and icing on the surface of the LNG tank further includes a standby inflation assembly. The standby inflation assembly includes an emergency inflation pipe 75. One end of the emergency inflation pipe 75 is connected to the storage tank 7, and an emergency breather shut-off valve 76 is provided on the emergency inflation pipe 75. When the flow regulating valve 5 fails and needs to be repaired, the emergency breather shut-off valve 76 can be opened, and inflation can be carried out through the emergency inflation pipe 75 to ensure that the storage tank 7 of the LNG tank contains dry air.

[0040] In some embodiments, the ship's compressed air device can be used as a standby air source when the air compressor 1 is damaged to supply dry air to the storage tank 7.

[0041] In some embodiments, a natural gas probe 71 and an oxygen content probe 72 are provided in the storage tank 7. The natural gas probe 71 is used to detect the natural gas in the storage tank 7, and the oxygen content probe 72 is used to detect the oxygen in the storage tank 7. Through the above settings, it is possible to check whether natural gas leakage and low oxygen content occur in the storage tank 7, avoiding the risk of asphyxiation to the personnel entering the storage tank 7.

[0042] In some embodiments, the LNG tank surface condensate and icing prevention system further includes a safety pipeline 41. One end of the safety pipeline 41 is connected to the outlet of the booster valve 4, and a first safety valve 42 is provided on the safety pipeline 41. By providing the safety pipeline 41, after the gas pressure at the outlet of the booster valve 4 exceeds the set value, the first safety valve 42 automatically opens for pressure relief, thereby ensuring the safety of the pressurization pipeline.

[0043] In some embodiments, the LNG tank surface condensate and icing prevention system further includes a second breather pipe 31. One end of the second breather pipe 31 is connected to the air bottle 3, and a second safety valve 32 is provided on the second breather pipe 31. By providing the second breather pipe 31, when the air pressure stored in the air bottle 3 is too high and exceeds the set pressure value, the air can push open the second safety valve 32 through the second breather pipe 31 for pressure relief, thereby ensuring the safety of the air bottle 3.

[0044] In some embodiments, the LNG tank surface condensate and icing prevention system further includes a nitrogen processing component. The nitrogen processing component includes a nitrogen generator 8 and a nitrogen bottle 9 that are connected to each other, and the nitrogen generator 8 is connected to the air bottle 3. Specifically, a stop check valve is provided on the pipeline between the nitrogen generator 8 and the air bottle 3. The nitrogen generator 8 processes the gas in the air bottle 3 to obtain nitrogen with a certain inertness, and stores the nitrogen in the nitrogen bottle 9 for subsequent direct use by users.

[0045] In some embodiments, the LNG tank surface condensate and icing prevention system further includes a third breather pipe 91. One end of the third breather pipe 91 is connected to the nitrogen bottle 9, and a third safety valve 92 is provided on the third breather pipe 91. Through the above settings, when the nitrogen pressure in the nitrogen bottle 9 exceeds the set value, the nitrogen can push open the third safety valve 92 through the third breather pipe 91 and be discharged, thereby ensuring the safety of the nitrogen bottle 9.

[0046] In some embodiments, the LNG tank surface condensate and icing prevention system further includes a discharge pipeline 93. One end of the discharge pipeline 93 is connected to the nitrogen bottle 9, and a discharge switch valve 94 is provided on the discharge pipeline 93. By providing the discharge pipeline 93, when the nitrogen bottle 9 is not in use, the nitrogen in the nitrogen bottle 9 can be completely discharged.

[0047] In some embodiments, the LNG tank surface condensation and icing prevention system further includes a fourth vent pipe 81. One end of the fourth vent pipe 81 is connected to the nitrogen generator 8, and a fourth safety valve is provided on the fourth vent pipe 81. Through the above arrangement, when the nitrogen pressure in the nitrogen generator 8 exceeds the set value, the nitrogen can push open the fourth safety valve and discharge through the fourth vent pipe 81, thereby ensuring the safety of the nitrogen generator 8.

[0048] Using the LNG tank surface condensation and icing prevention system to provide dry air for the storage tank 7 has low cost, and at the same time overcomes the problem that mechanical ventilation of the storage tank 7 will cause condensation and icing on the insulation surface of the LNG tank, and overcomes the situation of damage to the insulation.

[0049] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, rather than limiting the implementation manners of the present invention. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to enumerate all the implementation manners here. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the claims of the present invention.

Claims

1. The system for preventing condensation and freezing of LNG tank surface is characterized by: include: Air compressor (1); An air dryer (2), one end of the air dryer (2) being in communication with the air compressor (1); An air bottle (3), the air dryer (2) being in communication with the air bottle (3); a pressurizing pipeline, one end of which is in communication with the air bottle (3), the other end of which is in communication with a storage tank (7) in which an LNG tank is arranged, and a boosting valve (4) is provided on the pressurizing pipeline; a flow regulating valve (5), the flow regulating valve (5) being arranged on the pressurizing pipeline, and the flow regulating valve (5) being located between the boosting valve (4) and the storage compartment (7); A pressure differential sensor (6), wherein the pressure differential sensor (6) is arranged in the storage compartment (7), and the pressure differential sensor (6) is electrically connected to the flow regulating valve (5), and the pressure differential sensor (6) is capable of controlling the opening of the flow regulating valve (5).

2. The system for preventing condensation and icing on the surface of LNG tanks according to claim 1 is characterized in that: It also comprises a first air vent pipe (73), one end of which is in communication with the storage compartment (7), and a breathing valve (74) is provided on the first air vent pipe (73).

3. The system for preventing condensation and icing on the surface of LNG tanks according to claim 1 is characterized in that: It also includes a spare inflation component, which includes an emergency inflation pipe (75), one end of which is in communication with the storage compartment (7), and an emergency venting stop valve (76) is provided on the emergency inflation pipe (75).

4. The system for preventing condensation and icing on the surface of LNG tanks according to claim 1 is characterized in that: A natural gas probe (71) and an oxygen content probe (72) are provided in the storage cabin (7); the natural gas probe (71) is used to detect the natural gas in the storage cabin (7); and the oxygen content probe (72) is used to detect the oxygen in the storage cabin (7).

5. The system for preventing condensation and icing on the surface of LNG tanks according to claim 1 is characterized in that: It also comprises a safety pipeline (41), one end of which is connected to the outlet of the boost valve (4), and a first safety valve (42) is arranged on the safety pipeline (41).

6. The system for preventing condensation and icing on the surface of LNG tanks according to claim 1 is characterized in that: It also comprises a second air permeable pipe (31), one end of which is in communication with the air bottle (3), and a second safety valve (32) is provided on the second air permeable pipe (31).

7. The system for preventing condensation and icing on the surface of LNG tanks according to claim 1 is characterized in that: It also comprises a nitrogen processing assembly, which comprises a nitrogen generator (8) and a nitrogen bottle (9) which are connected to each other, and the nitrogen generator (8) is connected to the air bottle (3).

8. The system for preventing condensation and icing on the surface of LNG tanks according to claim 7 is characterized in that: It also comprises a third air permeable tube (91), one end of which is in communication with the nitrogen bottle (9), and a third safety valve (92) is provided on the third air permeable tube (91).

9. The system for preventing condensation and icing on the surface of LNG tanks according to claim 7, characterized in that: It also includes a discharge pipeline (93), one end of which is in communication with the nitrogen bottle (9), and a discharge switch valve (94) is provided on the discharge pipeline (93).

10. The system for preventing condensation and icing on the surface of an LNG tank according to claim 7, characterized in that: It also comprises a fourth air permeable pipe (81), one end of which is in communication with the nitrogen generator (8), and a fourth safety valve is provided on the fourth air permeable pipe (81).

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