A LNG gasification station low-temperature storage tank interface valve group system and control method thereof

Abstract

A LNG gasification station low-temperature storage tank interface valve group system, characterized in that it comprises a liquid inlet main pipe part and a liquid outlet main pipe part, the liquid inlet main pipe part comprises two branches, one of which is connected to the LNG storage tank booster liquid inlet pipe, a valve (4) is arranged on the storage tank booster liquid inlet main pipe and connected to an interface (B), and the other branch is provided with a start emergency cut-off valve (3), a ZSOV and a VIC are arranged at the valve (3), a valve (1) and a valve (2) are arranged downstream of the valve (3) to lead to the upper and lower liquid inlet main pipes of the storage tank respectively and are connected to interfaces (C) and (D), the interface (C) is connected to the upper liquid inlet of the storage tank, and the interface (D) is connected to the lower liquid inlet of the storage tank; the gas phase pipe is connected to the gas phase port of the storage tank through an interface (E), the gas phase pipe is a two-way ventilation pipe, the gas inlet pipe in the air inlet direction passes through an interface (I) connected to the storage tank booster, a valve (7) is arranged downstream of the interface (I), and then connected to the interface (E) and connected to the storage tank.

Description

Technical Field

[0001] The invention relates to a low-temperature storage tank interface valve group system of an LNG gasification station and a control method thereof, belonging to the field of LNG gasification station control systems. Background Art

[0002] At present, the inlet and outlet pipelines of storage tanks in conventional LNG gasification stations are crisscrossed, and the horizontal width of the pipelines is between 1000mm and 1400mm. The valves are difficult to operate, and separate pipeline ladders are required, which affects the overall appearance and poses a safety hazard. Summary of the invention

[0003] In order to solve the above-mentioned deficiencies and shortcomings, the present invention proposes a low-temperature storage tank interface valve group system for an LNG gasification station.

[0004] The technical solution adopted by the present invention to solve the technical problem is as follows:

[0005] An LNG gasification station low-temperature storage tank interface valve group system, characterized in that it includes a liquid inlet main pipe part and a liquid outlet main pipe part, the liquid inlet main pipe part includes two branches, one of which is connected to the LNG storage tank booster liquid inlet pipe, valve four is arranged on the storage tank booster liquid inlet main pipe and connected to interface two, the other branch is arranged to start emergency shut-off valve three, ZSOV and VIC are arranged at valve three, ZSOV is used for pneumatic emergency shut-off valve control (the valve switch can be remotely controlled in the control room), VIC is used for pneumatic emergency shut-off valve position feedback (the valve switch state can be observed in the control room), valve one and valve two are arranged downstream of valve three, which lead to the upper and lower liquid inlet main pipes of the storage tank respectively and are connected to interface three and interface four, interface three is connected to the upper liquid inlet of the storage tank, Interface 4 is connected to the lower liquid inlet of the storage tank; the gas phase pipe is connected to the gas phase port of the storage tank through interface 5, the gas phase pipe is a two-way ventilation pipe, the air intake pipe in the air intake direction passes through interface 9 connected to the storage tank supercharger and valve 7 is set downstream of interface 9 and then connected to interface 5 and connected to the storage tank, valve 8 and valve 9, valve 10, valve 11 are set in the air outlet direction, valve 8 is a bypass passage of valve 9, valve 10, valve 11, that is, valve 8 is in parallel with valve 9, valve 10, valve 11, valve 11 is a pressure check valve, which detects the pressure of the gas in the gas phase pipe. If it is higher than the set value, valve 11 automatically opens and is connected to the BOG pipeline through interface 10 to pour the gas into the BOG pipeline, thereby realizing the function of reducing the pressure of the storage tank; interface 6 connects the liquid outlet pipe to the liquid outlet of the storage tank, at An emergency shut-off valve five is arranged downstream of the liquid outlet pipe. Valve five is a starting valve. ZSOV and VIC are arranged at valve five. Valve six is ​​arranged downstream of valve five. Valve six is ​​a manual valve, which is then connected to interface eight. Interface eight leads to the liquid outlet main pipe. Safety valve group one is arranged upstream of emergency shut-off valve three in the liquid inlet main pipe. When the pipeline pressure is higher than the set value, safety valve group one opens, and a small amount of cryogenic liquid enters the vent pipe. The vent pipe is connected to the vent main pipe through interface seven. When valve three, valve one and valve two are closed at the same time, a closed pipeline is generated between valve three, valve one and valve two. The pipeline may exceed the design pressure. Therefore, safety valve group two is arranged between valve three, valve one and valve two. When the pipeline pressure is higher than the set value, safety valve group two opens, and a small amount of cryogenic liquid enters the vent pipe. , the vent pipe is connected to the vent main pipe through interface seven; when valve five and valve six are closed at the same time, a closed pipeline is generated between valve five and valve six, and the pipeline may exceed the design pressure, so a safety valve group three is arranged between valve five and valve six. When the pipeline pressure is higher than the set value, the safety valve group three opens, and a small amount of cryogenic liquid enters the vent pipe, and the vent pipe is connected to the vent main pipe through interface seven; a plurality of parallel safety valve groups are arranged downstream of the gas phase pipe, preferably two, namely, safety valve group four and safety valve group five. When the gas phase pipe pressure is higher than the set value, the safety valve group four and the safety valve group five are opened at the same time, and the excess gas is discharged into the vent pipe and connected to the vent main pipe through interface seven. If one of them fails, the other can still ensure normal operation and ensure system safety.

[0006] A control method for a low-temperature storage tank interface valve group system of an LNG gasification station, characterized in that when the pressure in the pipeline is higher than the set value of the safety valve, the safety valve group 1 is opened, and a small amount of cryogenic liquid enters the venting collection pipe through the safety valve group 1 and is collected to the valve group skid interface 7; because when the pneumatic emergency shut-off valve 3 and the manual shut-off valve 1 and valve 2 are closed at the same time, the LNG in the closed pipe section formed in the middle is naturally vaporized, which may cause the pressure in the pipeline to reach the pipeline design pressure or even higher than the design pressure, so a safety valve group 2 is arranged on the pipeline between the pneumatic emergency shut-off valve 3 and the manual shut-off valve 1 and valve 2, and when the pressure in the pipeline is higher than the set value of the safety valve, the safety valve is opened, and a small amount of cryogenic liquid enters the venting collection pipe through the safety valve and is collected to the valve group skid interface 7; because when the pneumatic emergency shut-off valve 5 and the manual shut-off valve 6 are closed at the same time, the LNG in the closed pipe section formed in the middle is naturally vaporized, which may cause the pressure in the pipeline to reach the pipeline design pressure or even higher than the design pressure, so a safety valve group 3 is arranged on the pipeline between the pneumatic emergency shut-off valve 5 and the manual shut-off valve 6, and when the pressure in the pipeline is higher than the set value of the safety valve, the safety valve is opened, and a small amount of cryogenic liquid enters the venting collection pipe through the safety valve and is collected to the valve group skid interface 7 When the valve is opened, a small amount of cryogenic liquid enters the discharge collecting pipe through the safety valve and is collected to the valve group skid interface seven; a manual stop valve 12 and safety valve group 4 and safety valve group 5 are set downstream of the valve group skid interface five. To ensure the safety of the LNG storage tank and prevent safety valve failure, two groups of safety valve groups are set, namely safety valve group 4 and safety valve group 5. The manual stop valve 12, safety valve group 4 and safety valve group 5 are connected in parallel. When the pressure in the storage tank is higher than the set value of the safety valve, the safety valve opens, and a large amount of cryogenic gas enters the discharge collecting pipe through the safety valve and is collected to the valve group skid interface seven. Interface seven of the group skid, when it is necessary to manually relieve the pressure of the storage tank, manually open the manual stop valve twelve, and a large amount of low-temperature gas enters the venting manifold through the safety valve and is collected to interface seven of the valve group skid to realize the function of reducing the pressure of the storage tank; the above venting manifold is connected to interface seven of the valve group skid, and interface seven is connected to the EAG venting main pipe of the station; interface one is connected to the liquid outlet of the LNG transport tank truck, interface two is connected to the liquid phase inlet of the storage tank booster outside the system, interface seven is connected to the venting main pipe, interface eight is connected to the liquid outlet main pipe, and interface nine is connected to the gas phase outlet of the storage tank booster.

[0007] The beneficial effect achieved by the present invention is: 14 valves of the storage tank interface and 4 groups of safety valves (safety relief + manual relief) are combined into a system, vacuum tube insulation is used in the system, and pipelines and valves are arranged in layers, which not only meets functional needs, but also reduces space and is easy to operate. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0009] Figure 1 It is a schematic diagram of the present invention. DETAILED DESCRIPTION

[0010] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0011] In the description of the present invention, it should be noted that the terms "upper", "lower", "horizontal", "inside", "outside", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they cannot be understood as limitations on the present invention.

[0012] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0013] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0014] Example 1

[0015] like Figure 1As shown, a LNG gasification station low-temperature storage tank interface valve group system includes a liquid inlet main pipe part and a liquid outlet main pipe part. The liquid inlet main pipe part includes two branches, one of which is connected to the LNG storage tank booster liquid inlet pipe, a valve four 4 is arranged on the storage tank booster liquid inlet main pipe and connected to the interface two B, and the other branch is arranged to start the emergency shut-off valve three 3, and a ZSOV and a VIC are arranged at the valve three 3. The ZSOV is used for pneumatic emergency shut-off valve control (the valve switch can be remotely controlled in the control room), and the VIC is used for pneumatic emergency shut-off valve position feedback (the valve switch state can be observed in the control room), and a valve one 1 and a valve two 2 are arranged downstream of the valve three 3, which are respectively connected to the upper and lower liquid inlet main pipes of the storage tank and connected to the interface three C and the interface four D, interface three C is connected to the upper liquid inlet of the storage tank, and interface four D is connected to the lower liquid inlet of the storage tank; the gas phase pipe is connected to the gas phase port of the storage tank through interface five E, and the gas phase pipe is a two-way ventilation pipe. The air intake pipe in the air intake direction passes through interface nine I connected to the tank supercharger and a valve seven 7 is set downstream of interface nine I and then connected to interface five E and connected to the storage tank. Valve eight 8 and valve nine 9, valve ten 10, valve eleven 11 are set in the air outlet direction. Valve eight 8 is a bypass passage of valve nine 9, valve ten 10, valve eleven 11, that is, valve eight 8 is in parallel with valve nine 9, valve ten 10, valve eleven 11, and valve eleven 11 is a pressure detection valve, which detects the pressure of the gas in the gas phase pipe. If it is higher than the set value, valve eleven 11 automatically opens And it is connected to the BOG pipeline through interface 10J to pour the gas into the BOG pipeline to realize the function of reducing the pressure of the storage tank; interface 6F connects the liquid outlet pipe to the liquid outlet of the storage tank, and an emergency shut-off valve 55 is set downstream of the liquid outlet pipe. Valve 55 is a starting valve. ZSOV and VIC are set at valve 55. Valve 66 is set downstream of valve 55. Valve 66 is a manual valve, and then connected to interface 8H. Interface 8H leads to the liquid outlet main pipe; safety valve group 121 is set upstream of the emergency shut-off valve 33 of the liquid inlet main pipe. When the pipeline pressure is higher than the set value, the safety valve group 121 opens, and a small amount of low-temperature liquid enters the vent pipe. The vent pipe is connected to the vent main pipe through interface 7G; when valve 33, valve 11, and valve 22 are closed at the same time When the pressure of the pipeline is higher than the set value, the safety valve group 22 opens, and a small amount of cryogenic liquid enters the discharge pipe, and the discharge pipe is connected to the discharge main pipe through the interface 7G; when the valve 55 and the valve 66 are closed at the same time, a closed pipeline is generated between the valve 55 and the valve 66, and the pipeline may exceed the design pressure, so the safety valve group 3 23 is set between the valve 55 and the valve 66, and the safety valve group 3 23 opens when the pipeline pressure is higher than the set value, and a small amount of cryogenic liquid enters the discharge pipe, and the discharge pipe is connected to the discharge main pipe through the interface 7G;A plurality of parallel safety valve groups are arranged downstream of the gas phase pipe, preferably two, namely, the safety valve group 24 and the safety valve group 25. When the pressure of the gas phase pipe is higher than the set value, the safety valve group 24 and the safety valve group 25 are opened at the same time, and the excess gas is discharged into the discharge pipe and connected to the discharge main pipe through the interface 7G. If one of them fails, the other can still ensure normal operation and ensure system safety. ;

[0016] System release process: when the pressure in the pipeline is higher than the set value of the safety valve, the safety valve group 21 opens, and a small amount of cryogenic liquid enters the release collection pipe through the safety valve group 21 and is collected in the valve group skid interface 7G; because when the pneumatic emergency shut-off valve 33 and the manual shut-off valve 11 and valve 22 are closed at the same time, the LNG in the closed pipe section formed in the middle will naturally gasify, which may make the pressure in the pipeline reach the pipeline design pressure or even higher than the design pressure. Therefore, a safety valve group 22 is installed on the pipeline between the pneumatic emergency shut-off valve 33 and the manual shut-off valve 11 and valve 22. The pressure in the pipeline is higher than the safety valve When the set value is reached, the safety valve opens, and a small amount of cryogenic liquid enters the discharge collection pipe through the safety valve and is collected to the valve group skid interface 7G; when the pneumatic emergency shut-off valve 55 and the manual shut-off valve 66 are closed at the same time, the LNG in the closed pipe section formed in the middle will naturally gasify, which may cause the pressure in the pipeline to reach the pipeline design pressure or even higher than the design pressure. Therefore, a safety valve group 3 23 is installed on the pipeline between the pneumatic emergency shut-off valve 55 and the manual shut-off valve 66. When the pressure in the pipeline is higher than the set value of the safety valve, the safety valve opens, and a small amount of cryogenic liquid enters the discharge collection pipe through the safety valve and is collected to Valve group skid interface 7G; manual stop valve 12 12 and safety valve group 4 24 and safety valve group 5 25 are set downstream of valve group skid interface 5E. To ensure the safety of LNG storage tanks and prevent safety valve failure, two groups of safety valve groups are set, namely safety valve group 4 24 and safety valve group 5 25. The manual stop valve 12 12, safety valve group 4 24 and safety valve group 5 25 are connected in parallel. When the pressure in the storage tank is higher than the set value of the safety valve, the safety valve opens, and a large amount of low-temperature gas enters the discharge collection pipe through the safety valve and is collected to valve group skid interface 7G. When the storage tank needs to be manually depressurized, it is manually opened. Open the manual stop valve 12 (normally the manual stop valve 12 is in the closed state), and a large amount of low-temperature gas enters the vent collecting pipe through the safety valve and is collected to the valve group skid interface 7G to realize the function of reducing the pressure of the storage tank; the above vent collecting pipe is connected to the valve group skid interface 7G, and the interface 7G is connected to the station EAG vent main pipe; interface 1A is connected to the liquid outlet of the LNG transport tank truck, interface 2B is connected to the liquid phase inlet of the tank booster outside the system, interface 7G is connected to the vent main pipe, interface 8H is connected to the liquid outlet main pipe, and interface 9I is connected to the gas phase outlet of the tank booster.

[0017] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A control method for a low-temperature storage tank interface valve group system of an LNG gasification station, characterized in that: When the pressure in the pipeline is higher than the set value of the safety valve, the safety valve group 1 opens, and a small amount of cryogenic liquid enters the venting and collecting pipe through the safety valve group 1 and is collected to the valve group skid interface 7; because when the pneumatic emergency shut-off valve 3 and the manual shut-off valve 1 and valve 2 are closed at the same time, the LNG in the closed pipe section formed in the middle will naturally vaporize, so that the pressure in the pipeline reaches the pipeline design pressure or even higher than the design pressure, so the safety valve group 2 is set on the pipeline between the pneumatic emergency shut-off valve 3 and the manual shut-off valve 1 and valve 2. When the pressure in the pipeline is higher than the set value of the safety valve, the safety valve opens, and a small amount of cryogenic liquid enters the venting and collecting pipe through the safety valve and is collected to the valve group skid interface 7; because when the pneumatic emergency shut-off valve 5 and the manual shut-off valve 6 are closed at the same time, the LNG in the closed pipe section formed in the middle will naturally vaporize, so that the pressure in the pipeline reaches the pipeline design pressure or even higher than the design pressure, so the safety valve group 3 is set on the pipeline between the pneumatic emergency shut-off valve 5 and the manual shut-off valve 6. When the pressure in the pipeline is higher than the set value of the safety valve, the safety valve opens. , a small amount of cryogenic liquid enters the venting collection pipe through the safety valve and is collected to the valve group skid interface seven; a manual stop valve 12 and safety valve group 4 and safety valve group 5 are set downstream of the valve group skid interface five to ensure the safety of the LNG storage tank and prevent safety valve failure. Therefore, two groups of safety valve groups are set, namely safety valve group 4 and safety valve group 5. The manual stop valve 12, safety valve group 4 and safety valve group 5 are connected in parallel. When the pressure in the storage tank is higher than the set value of the safety valve, the safety valve opens, and a large amount of cryogenic gas enters the venting collection pipe through the safety valve and is collected to the valve group skid interface seven. When it is necessary to manually relieve the pressure of the storage tank, the manual stop valve 12 is manually opened to realize the function of reducing the pressure of the storage tank; the above venting collection pipe is connected to the valve group skid interface seven, and the interface seven is connected to the station EAG venting main pipe; interface one is connected to the liquid outlet of the LNG transport tank truck, interface two is connected to the liquid phase inlet of the tank booster outside the system, interface seven is connected to the venting main pipe, interface eight is connected to the liquid outlet main pipe, and interface nine is connected to the gas phase outlet of the tank booster; The LNG gasification station low-temperature tank interface valve group system includes: an inlet main pipe part and an outlet main pipe part. The inlet main pipe part includes two branches, one of which is connected to the LNG tank booster inlet pipe. Valve 4 is arranged on the tank booster inlet main pipe and connected to interface 2. The other branch is arranged to start emergency shut-off valve 3. ZSOV and VIC are arranged at emergency shut-off valve 3. ZSOV is used for pneumatic emergency shut-off valve control, and VIC is used for pneumatic emergency shut-off valve position feedback. Valve 1 and valve 2 are arranged downstream of emergency shut-off valve 3, which lead to the upper and lower inlet main pipes of the tank respectively and are connected to interfaces 3 and 4. Interface 3 is connected to the upper liquid inlet of the tank, and interface 4 is connected to the lower liquid inlet of the tank; the gas phase pipe is connected to the gas phase port of the tank through interface 5. The gas phase pipe is a two-way ventilation pipe. The air intake pipe in the air intake direction passes through the interface 9 connected to the tank booster and a valve 7 is set downstream of the interface 9 and then connected to the interface 5 and connected to the tank. The valve 8 and the combination of valve 9, valve 10 and valve 11 are set in the air outlet direction. Valve 8 is a bypass passage of the combination of valve 9, valve 10 and valve 11, that is, valve 8 is in parallel with the combination of valve 9, valve 10 and valve 11. Valve 11 is a pressure check valve, which detects the pressure of the gas in the gas phase pipe. If it is higher than the set value, valve 11 automatically opens and is connected to the BOG pipeline through interface 10 to pour the gas into the BOG pipeline, thereby realizing the function of reducing the pressure of the tank. Interface 6 connects the liquid outlet pipe to the liquid outlet of the tank, and an emergency shut-off valve 5 is set downstream of the liquid outlet pipe. The emergency shut-off valve 5 is a starting valve. ZSOV and VIC are provided at the cut-off valve five, and valve six is ​​provided downstream of the emergency cut-off valve five. Valve six is ​​a manual valve, which is then connected to interface eight, and interface eight leads to the liquid outlet main pipe; safety valve group one is provided upstream of the emergency cut-off valve three of the liquid inlet main pipe. When the pipeline pressure is higher than the set value, the safety valve group one opens, and a small amount of cryogenic liquid enters the vent pipe, and the vent pipe is connected to the vent main pipe through interface seven; when the emergency cut-off valve three, valve one, and valve two are closed at the same time, a closed pipeline is generated between the emergency cut-off valve three, valve one, and valve two, and the pipeline has a pressure exceeding the design pressure, so a safety valve group two is provided between the emergency cut-off valve three, valve one, and valve two. When the pipeline pressure is higher than the set value, the safety valve group two opens, and a small amount of cryogenic liquid enters the vent pipe, and the vent pipe is connected to the vent main pipe through interface seven. Port seven is connected to the vent main pipe; when the emergency shut-off valve five and valve six are closed at the same time, a closed pipeline is generated between the emergency shut-off valve five and valve six, and the pipeline has a pressure exceeding the design pressure, so a safety valve group three is set between the emergency shut-off valve five and valve six. When the pipeline pressure is higher than the set value, the safety valve group three opens, and a small amount of cryogenic liquid enters the vent pipe, and the vent pipe is connected to the vent main pipe through interface seven; a plurality of parallel safety valve groups are set downstream of the gas phase pipe, two of which are safety valve group four and safety valve group five. When the gas phase pipe pressure is higher than the set value, the safety valve group four and the safety valve group five are opened at the same time, and the excess gas is discharged into the vent pipe and connected to the vent main pipe through interface seven. If one of them fails, the other can still ensure normal operation and ensure system safety.

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