Purging pipeline in LNG (Liquefied Natural Gas) fuel tank double-gas supply system
By designing a purge pipeline including gas-phase and liquid-phase filling pipes, using components such as stop-check valves, check valves, venturi pipes and three-way valves, efficient purge and simple operation of the LNG fuel tank dual gas supply system is achieved, and the problems of complex operations and frequent disassembly and assembly in the prior art are solved.
Patent Information
- Application Number
- CN202421650558.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-12
- Publication Date
- 2025-05-02
- Estimated Expiration
- 2034-07-12
AI Technical Summary
The purge pipelines in the existing LNG fuel tank dual gas supply system are complex in operation and are prone to delay work. They often need to be disassembled and assembled in the dual gas supply system, which is cumbersome in operation.
A purge pipeline circuit including a gas-phase filling pipe and a liquid-phase filling pipe is designed, connected to the gas-phase and liquid-phase filling pipes through the first and second purge pipes, a first and second stop check valves, a check valve and a Venturi pipe are provided, and the automatic switching and pressure enhancement of the nitrogen gas source is achieved by using a three-way valve and a booster pump to reduce shutdown and disassembly.
It achieves improvement of purge efficiency and simplicity of operation, reduces frequent disassembly and assembly of the dual-gas supply system, and can replace or fill a nitrogen source without shutting down, thereby improving the use rate of nitrogen.
Smart Images
Figure CN222824117U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the field of pressure vessels, in particular to a purge pipeline in a dual gas supply system of an LNG fuel tank. Background Art
[0002] The LNG fuel tank dual gas supply system includes two independent LNG supply paths, which can be supplied from two different fuel tanks, or one fuel tank is equipped with two independent gas supply systems, which are usually used in transportation applications such as heavy trucks, buses, river vessels or marine vessels. In order to ensure the normal operation of the two gas supply systems, when one gas supply system is in operation, the other gas supply system needs to be purged, which requires the gas supply system to be connected to the purge pipeline. In order to prevent the natural gas in the gas supply system from flowing back into the purge pipeline, a one-way valve is generally directly installed at the connection between the gas supply system and the purge pipeline. Since the one-way valve only has the function of preventing backflow and has no function of cutting off the medium, the one-way valve is easily damaged under high pressure and low temperature environment. At present, the purge pipelines on the market are generally single-tube, single-gas source, and single-connector, that is, a nitrogen gas source, a purge pipe and a connector. Before purging, the purge pipe is connected to the gas supply system through the connector. The purge pipe is connected to the nitrogen gas source. When the nitrogen gas source is turned on, the gas supply system can be purged through the purge pipe. However, when the nitrogen stock in the nitrogen gas source is insufficient, the purge pipe needs to be connected to a new nitrogen gas source after shutdown. The operation is complicated and easily delays the purge work. When purging the dual gas supply system, the purge pipe needs to be disassembled and assembled before the two gas supply systems can be purged separately, which requires frequent shutdowns and disassembly, and the operation is cumbersome. Utility Model Content
[0003] The utility model aims to provide a purge pipeline in a dual gas supply system of an LNG fuel tank, which has high purge efficiency and good isolation between the purge pipeline and the gas supply system.
[0004] To achieve the above-mentioned purpose, the technical solution adopted by the utility model is: the purge pipeline in the dual gas supply system of the LNG fuel tank includes: a gas phase filling pipe and a liquid phase filling pipe, a first purge pipe is connected to the gas phase filling pipe, a first stop check valve and a first one-way valve are arranged on the first purge pipe, the first stop check valve is close to the junction between the gas phase filling pipe and the first purge pipe, a first venturi tube is arranged between the first stop check valve and the first one-way valve, a second purge pipe is connected to the liquid phase filling pipe, and a second stop check valve and a second one-way valve are arranged on the second purge pipe The second stop check valve is close to the junction between the liquid filling pipe and the second purge pipe, a second venturi tube is arranged between the second stop check valve and the second one-way valve, the first purge pipe and the second purge pipe are connected to the gas delivery auxiliary pipe through the first three-way valve, the gas delivery auxiliary pipe is connected with the first branch pipe and the second branch pipe, a booster pump is arranged on the first branch pipe, the first branch pipe and the second branch pipe are connected to the gas delivery main pipe through the second three-way valve, a gasification tank is arranged on the gas delivery main pipe, the gasification tank is connected to two nitrogen gas sources respectively through two third branch pipes, and a third stop check valve is arranged on the third branch pipe.
[0005] Furthermore, the purge pipeline in the aforementioned LNG fuel tank dual gas supply system, wherein the first stop check valve, the first one-way valve, the second stop check valve, the second one-way valve, the first three-way valve, the second three-way valve, the boosting pump and the third stop check valve are all electrically connected to the central control device.
[0006] Furthermore, in the aforementioned purge pipeline in the dual gas supply system of the LNG fuel tank, a first flow meter is provided on the gas main pipe between the gasification tank and the second three-way valve, and a second flow meter is provided on the first branch pipe, and the second flow meter is located in the outlet direction of the boosting pump, and both the first flow meter and the second flow meter are electrically connected to the central control device.
[0007] Furthermore, in the aforementioned LNG fuel tank dual gas supply system, a first drain pipe is arranged between the first stop check valve and the first one-way valve, a third one-way valve is arranged on the first drain pipe, a second drain pipe is arranged between the second stop check valve and the second one-way valve, and a fourth one-way valve is arranged on the second drain pipe.
[0008] Furthermore, in the aforementioned purge pipeline in the dual gas supply system of the LNG fuel tank, a first pressure gauge and a first natural gas concentration detector are arranged between the first stop check valve and the first one-way valve; a second pressure gauge and a second natural gas concentration detector are arranged between the second stop check valve and the second one-way valve, the first pressure gauge and the first natural gas concentration detector are both electrically connected to the third one-way valve through the central control device, and the second pressure gauge and the second natural gas concentration detector are both electrically connected to the fourth one-way valve through the central control device.
[0009] Furthermore, in the aforementioned purge pipeline in the dual gas supply system of the LNG fuel tank, a pressure overload alarm component and a gas leakage alarm component are provided in the central control device.
[0010] Furthermore, the purge pipeline in the aforementioned LNG fuel tank dual gas supply system, wherein the first purge pipe, the second purge pipe, the gas transmission auxiliary pipe, the first branch pipe, the second branch pipe, the gas transmission main pipe, the gasification tank and the third branch pipe are all covered with thermal insulation cotton.
[0011] The advantages of the utility model are as follows: by arranging the first purge pipe and the second purge pipe, the gas phase filling pipe and the liquid phase filling pipe in the dual gas supply system of the LNG fuel tank can be connected. When purging the gas phase filling pipe or the liquid phase filling pipe, it can be realized by switching the first three-way valve, and there is no need to stop the machine for disassembly and assembly, which is convenient and fast; the first venturi tube and the second venturi tube are respectively arranged in the first purge pipe and the second purge pipe, which can increase the flow rate of nitrogen, thereby improving the purging efficiency; by being connected to two nitrogen gas sources, when one nitrogen gas source is insufficient in nitrogen, the third stop check valve on the corresponding third branch pipe can be opened to switch to another full nitrogen gas source for gas supply, and the insufficient nitrogen gas source can be replaced or filled during the purging process, and there is no need to stop the machine, which is convenient and fast; the first branch pipe and the second venturi tube are connected on the gas transmission auxiliary pipe. A second branch pipe is provided with a booster pump on the first branch pipe. When the nitrogen pressure in the nitrogen source is sufficient, it can be transported through the second branch pipe for purging. When the nitrogen pressure in the nitrogen source is insufficient, it can be switched to the first branch pipe through the second three-way valve and pressurized by the booster pump so that the nitrogen has sufficient pressure for purging, thereby improving the utilization rate of nitrogen. A first stop check valve is provided near the junction between the gas phase filling pipe and the first purge pipe, and a second stop check valve is provided near the junction between the liquid phase filling pipe and the second purge pipe. The first stop check valve and the second stop check valve can simultaneously have the functions of cutting off the medium and preventing the medium from flowing back, and can have excellent anti-backflow effect under high pressure and low temperature environment. A third stop check valve is provided on the third branch pipe connected to the nitrogen source, which can improve the anti-leakage ability of the nitrogen source. BRIEF DESCRIPTION OF THE DRAWINGS
[0012] Figure 1 It is a structural schematic diagram of Embodiment 1 of the purge pipeline in the dual gas supply system of the LNG fuel tank described in the utility model.
[0013] Figure 2 It is a structural schematic diagram of the second embodiment of the purge pipeline in the dual gas supply system of the LNG fuel tank described in the utility model.
[0014] Figure 3 It is a structural schematic diagram of the third embodiment of the purge pipeline in the dual gas supply system of the LNG fuel tank described in the utility model. DETAILED DESCRIPTION
[0015] The technical solution of the utility model is further described below in conjunction with the accompanying drawings and preferred embodiments.
[0016] Embodiment 1
[0017] like Figure 1 As shown, the purge pipeline in the dual gas supply system of the LNG fuel tank described in the utility model includes: a gas phase filling pipe 1 and a liquid phase filling pipe 2, the gas phase filling pipe 1 is connected with a first purge pipe 11, the first purge pipe 11 is provided with a first stop check valve 12 and a first one-way valve 13, the first stop check valve 12 is close to the connection between the gas phase filling pipe 1 and the first purge pipe 11, the first stop check valve 12 has the function of both cutting off the medium and preventing the medium from flowing back, when the gas phase filling pipe 1 is filled, the gas phase natural gas is not easy to flow back into the first purge pipe 11 due to the large pressure, which plays a protective role for the first one-way valve 13, and the simultaneous provision of the first stop check valve 12 and the first one-way valve 13 can improve the protection of the purge pipeline, and a first venturi tube 14 is provided between the first stop check valve 12 and the first one-way valve 13, and the first venturi tube 14 can increase the flow of the gas in the first purge pipe 11. Speed, thereby improving the purging efficiency, a second purging pipe 21 is connected to the liquid phase filling pipe 2, a second stop check valve 22 and a second one-way valve 23 are arranged on the second purging pipe 21, the second stop check valve 22 is close to the connection between the liquid phase filling pipe 2 and the second purging pipe 21, a second venturi tube 24 is arranged between the second stop check valve 22 and the second one-way valve 23, the first purging pipe 11 and the second purging pipe 21 are connected to the gas delivery auxiliary pipe 4 through the first three-way valve 3 A first branch pipe 41 and a second branch pipe 42 are connected to the gas delivery auxiliary pipe 4, a booster pump 43 is arranged on the first branch pipe 41, the first branch pipe 41 and the second branch pipe 42 are connected to the gas delivery main pipe 6 through a second three-way valve 5, a gasification tank 61 is arranged on the gas delivery main pipe 6, and the gasification tank 61 is respectively connected to two nitrogen gas sources 7 through two third branch pipes 62. The nitrogen gas source 7 in this embodiment is a liquid nitrogen tank, and a third stop check valve 621 is arranged on the third branch pipe 62.
[0018] If it is necessary to purge the gas phase filling pipe 1, the first three-way valve 3 is switched to the first purge pipe 11 passage, and the first stop check valve 12 and the first one-way valve 13 on the first purge pipe 11 are opened, the second three-way valve 5 is switched to the second branch pipe 42 passage, and the third stop check valve 621 on any third branch pipe 62 is opened, and the liquid nitrogen in the nitrogen source 7 enters the gasification tank 61 through the third branch pipe 62, and the pressure of the liquid nitrogen in the gasification tank 61 is reduced and quickly converted into nitrogen, and then passes through the gas main pipe 6, the second branch pipe 42, the gas delivery auxiliary pipe 4, the first purge pipe 6, the second branch pipe 42, the gas delivery auxiliary pipe 4, the first purge pipe 6, the second branch pipe 42, the second purge pipe 4, the second purge pipe 6, the second branch pipe 42, the second purge pipe 4, the second purge pipe 6, the second branch pipe 42, the second purge pipe 4, the second purge pipe 6, the second branch pipe 42, the second purge pipe 4, the second purge pipe 6, the second branch pipe 42, the second purge pipe 4, the second purge pipe 6, the second branch pipe 42, the second purge pipe 4, the second purge pipe 6, the second purge pipe 4 ... The gas phase filling pipe 1 entering through the pipe 11 is purged, and the purging efficiency can be improved by the pressurization and speed-increasing effect of the venturi tube 14 in the first purging pipe 11. When the nitrogen pressure in the nitrogen source 7 is reduced and is not enough for purging, the second three-way valve 5 will switch to the first branch pipe 41 passage, and start the booster pump 43 at the same time, and increase the purging pressure through the booster pump 43. When the pressure required for purging cannot be met under the boosting effect of the booster pump 43, the third stop check valve 621 on the other third branch pipe 62 is opened, and the second three-way valve 5 is switched back to the second branch pipe 42 passage. The working principle of purging the liquid phase filling pipe 2 is the same.
[0019] Since liquid nitrogen has an endothermic reaction during the gasification process, it will lower the surrounding temperature and easily form condensed water on the pipelines and the gasification tank 61. In order to protect the pipelines and the gasification tank 61, the first purge pipe 11, the second purge pipe 21, the gas delivery auxiliary pipe 4, the first branch pipe 41, the second branch pipe 42, the gas delivery main pipe 6, the gasification tank 61 and the third branch pipe 62 need to be covered with thermal insulation cotton, which is not shown in the figure.
[0020] Embodiment 2
[0021] In order to automate the purge pipeline, a central control device 8 needs to be set up. The first stop check valve 12, the first one-way valve 13, the second stop check valve 22, the second one-way valve 23, the first three-way valve 3, the second three-way valve 5, the boosting pump 43 and the third stop check valve 621 are all electrically connected to the central control device 8. A first flow meter 63 is provided on the gas transmission main pipe 6 between the gasification tank 61 and the second three-way valve 5, and a second flow meter 44 is provided on the first branch pipe 41. The second flow meter 44 is located at the outlet end direction of the boosting pump 43. The first flow meter 63 and the second flow meter 44 are both electrically connected to the central control device 8. Before purging, the central control device 8 can automatically control the first three-way valve 3 to switch to the first purge pipe 11 or the second purge pipe 21 according to the purge requirements, and open the stop check valve and the one-way valve on the purge pipe. During the purging process, the nitrogen flow in the delivery main pipe 6 is monitored by the first flow meter 63 to determine whether the pressure in the nitrogen source 7 is sufficient. When the flow displayed by the first flow meter 63 is lower than the flow set by the central control device 8, it means that the amount of nitrogen in the nitrogen source 7 is insufficient, and the central control device 8 will control the second three-way valve 5 to switch to the first branch pipe 41 passage and start the booster pump 43. When the second flowmeter 44 on the first branch pipe 41 monitors that the nitrogen flow rate in the first branch pipe 41 is lower than the flow rate set by the central control device 8, it means that the amount of nitrogen in the nitrogen source 7 is almost gone. At this time, the central control device 8 can open another third stop check valve 621 to make the full nitrogen source 7 output nitrogen. When the nitrogen flow rate in the gas transmission main pipe 6 monitored by the first flowmeter 63 is higher than the flow rate set by the central control device 8, the central control device 8 will control the second three-way valve 5 to switch to the second branch pipe 42 passage.
[0022] Embodiment 3
[0023] In order to prevent the first stop check valve 12 and the second stop check valve 22 from being damaged during long-term use, thereby causing natural gas to flow back into the purge pipeline or become blocked, a monitoring system needs to be provided in the purge pipeline. A first drain pipe 15, a first pressure gauge 16 and a first natural gas concentration detector 17 are arranged on the first purge pipe 11 between the first stop check valve 12 and the first one-way valve 13, and a third one-way valve 18 is arranged on the first drain pipe 15. The third one-way valve 18 can prevent outside air from entering the first purge pipe 11, and the first pressure gauge 16 and the first natural gas concentration detector 17 are electrically connected to the third one-way valve 18 through the central control device 8; a second drain pipe 25, a second pressure gauge 26 and a second natural gas concentration detector 27 are arranged between the second stop check valve 22 and the second one-way valve 22, and a fourth one-way valve 28 is arranged on the second drain pipe 25. The second pressure gauge 26 and the second natural gas concentration detector 27 are electrically connected to the third one-way valve 28 through the central control device 8, and a pressure overload alarm component and a gas leakage alarm component are arranged in the central control device 8. Taking the first purge pipe 11 as an example, during the filling process of the gas-phase filling pipe 1, when natural gas flows back into the first purge pipe 11 located between the first stop check valve 12 and the first one-way valve 13, and the natural gas concentration monitored by the first natural gas concentration detector 17 exceeds the natural gas concentration safety threshold set by the central control device 8, the central control device 8 will open the third one-way valve 18 to discharge the leaked natural gas from the first exhaust pipe 15 to the outside, and at the same time, an alarm will be sounded through the gas leakage alarm component, so that the staff can replace or repair the damaged first stop check valve 12; during the process of purging the gas-phase filling pipe 1, when the pressure monitored by the first pressure gauge 16 in the first purge pipe 11 between the first stop check valve 12 and the first one-way valve 13 is greater than the pressure safety threshold set by the central control device 8, the central control device 8 will open the third one-way valve 18. The one-way valve 18 allows the nitrogen accumulated in the first purge pipe 11 to be discharged to the outside through the first exhaust pipe 15. At the same time, an alarm will be sounded through the pressure overload alarm component, and the opened third stop check valve 621 will be controlled to be closed. The staff can replace or repair the damaged first stop check valve 12. The pressure overload alarm component and the gas leakage alarm component in the central control device 8 need to be manually operated to be closed after the alarm is sounded, and the third one-way valve 18 on the first exhaust pipe 15 and the fourth one-way valve 28 on the second exhaust pipe 25 also need to be manually operated to be closed. This is because the pressure will decrease or the natural gas concentration will decrease when the gas is discharged to the outside. At this time, the central control device 8 will misdiagnose and the pressure overload alarm component or the gas leakage alarm component will no longer alarm, resulting in the staff being unable to troubleshoot the fault in time.
[0024] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model rather than to limit it. Although the utility model is described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the utility model can still be modified or replaced by equivalents, and any modification or equivalent replacement that does not depart from the spirit and scope of the utility model should be included in the scope of protection of the claims of the utility model.
Claims
1. The purge pipeline in the dual gas supply system of LNG fuel tanks includes: The gas phase filling pipe and the liquid phase filling pipe are characterized in that: the gas phase filling pipe is connected to the first purge pipe, the first purge pipe is provided with a first stop check valve and a first one-way valve, the first stop check valve is close to the junction between the gas phase filling pipe and the first purge pipe, a first venturi tube is provided between the first stop check valve and the first one-way valve, the liquid phase filling pipe is connected to the second purge pipe, the second stop check valve and the second one-way valve are provided on the second purge pipe, the second stop check valve is close to the junction between the liquid phase filling pipe and the second purge pipe A second venturi tube is arranged at the junction between the sweep pipes and between the second stop check valve and the second one-way valve. The first sweep pipe and the second sweep pipe are connected to the gas delivery auxiliary pipe through the first three-way valve. The gas delivery auxiliary pipe is connected with the first branch pipe and the second branch pipe. A booster pump is arranged on the first branch pipe. The first branch pipe and the second branch pipe are connected to the gas delivery main pipe through the second three-way valve. A gasification tank is arranged on the gas delivery main pipe. The gasification tank is connected to two nitrogen gas sources respectively through two third branch pipes. A third stop check valve is arranged on the third branch pipe.
2. The purge pipeline in the dual gas supply system of the LNG fuel tank according to claim 1 is characterized in that: The first stop check valve, the first one-way valve, the second stop check valve, the second one-way valve, the first three-way valve, the second three-way valve, the booster pump and the third stop check valve are all electrically connected to the central control device.
3. The purge pipeline in the dual gas supply system of the LNG fuel tank according to claim 2 is characterized in that: A first flow meter is arranged on the gas main pipe between the gasification tank and the second three-way valve, a second flow meter is arranged on the first branch pipe, the second flow meter is located at the outlet end of the booster pump, and both the first flow meter and the second flow meter are electrically connected to the central control device.
4. The purge pipeline in the dual gas supply system of the LNG fuel tank according to claim 2 is characterized in that: A first drain pipe is arranged between the first stop check valve and the first one-way valve, a third one-way valve is arranged on the first drain pipe, a second drain pipe is arranged between the second stop check valve and the second one-way valve, a fourth one-way valve is arranged on the second drain pipe.
5. The purge pipeline in the dual gas supply system of the LNG fuel tank according to claim 4 is characterized in that: A first pressure gauge and a first natural gas concentration detector are provided between the first stop check valve and the first one-way valve; a second pressure gauge and a second natural gas concentration detector are provided between the second stop check valve and the second one-way valve, the first pressure gauge and the first natural gas concentration detector are both electrically connected to the third one-way valve through the central control device, and the second pressure gauge and the second natural gas concentration detector are both electrically connected to the fourth one-way valve through the central control device.
6. The purge pipeline in the dual gas supply system of the LNG fuel tank according to claim 5 is characterized in that: A pressure overload alarm component and a gas leakage alarm component are arranged in the central control device.
7. The purge pipeline in the dual gas supply system of the LNG fuel tank according to claim 1 is characterized in that: The first purge pipe, the second purge pipe, the gas transmission auxiliary pipe, the first branch pipe, the second branch pipe, the gas transmission main pipe, the gasification tank and the third branch pipe are all covered with heat insulation cotton.