Liquid adding system for LNG (Liquefied Natural Gas) liquid adding machine

Abstract

The utility model discloses a liquid adding system for an LNG (Liquefied Natural Gas) liquid adding machine, which relates to the technical field of LNG liquid adding and comprises a liquid outlet pipeline communicated with a liquid outlet of the LNG liquid adding machine, a filling hose communicated with the tail end of the liquid outlet pipeline, a filling gun communicated with the filling hose, a gas return pipeline component and a precooling pipeline component. According to the scheme, through more scientific and reasonable circulating pre-cooling process design, full pre-cooling of a pipeline system and core components can be guaranteed in the large and small circulating pre-cooling process of the LNG liquid adding machine, and meanwhile the situation that the service life and the quality stability of the gas phase flow meter are affected by scouring of an LNG low-temperature medium in the pre-cooling process is avoided.

Description

Technical Field

[0001] This utility model relates to the field of LNG dispensing technology, and more specifically to the field of dispensing system technology for LNG dispensers. Background Technology

[0002] LNG dispensers add LNG to LNG tank trucks or container trucks. Because LNG dispensers require pipeline pre-cooling before dispensing (pre-cooling is free), if LNG is dispensed directly to tank trucks or container trucks without pre-cooling after activation, LNG theft is likely to occur. Regarding anti-theft and accurate metering technologies for LNG dispensers, existing patents disclose the following technologies:

[0003] Patent publication CN103629525A, entitled "Intelligent High-Precision LNG Refueling Metering Device," discloses the following: An intelligent high-precision LNG refueling metering device, wherein the refueling pipeline includes a liquid inlet connected to a refueling gun via a liquid phase mass flow meter. The outlet of the liquid phase mass flow meter is connected to two branches, one of which is connected to the refueling gun, and the other branch is connected to a circulation switch valve. The inlet of the circulation switch valve is connected to the outlet of the liquid phase mass flow meter, and the outlet of the circulation switch valve is connected to a circulation port. A gas phase mass flow meter is installed on the pipeline between the circulation switch valve and the circulation port. This invention adds a gas phase mass flow meter to the pipeline between the first check valve and the circulation port, which not only ensures high metering accuracy and eliminates the impact of leakage from the circulating pneumatic valve on the metering accuracy, but also features high intelligence and prevents human error and LNG theft.

[0004] In patent CN103629525A, the circulating switching valve is prone to LNG leakage. The leaked liquid LNG returns to the dispenser through the gas phase mass flow meter on the return gas pipeline. Because LNG has an extremely low temperature, it easily absorbs heat and vaporizes in the return gas pipeline, producing a two-phase gas-liquid system, leading to inaccurate measurement by the gas phase mass flow meter. The gas phase mass flow meter is constantly exposed to the low-temperature LNG medium, affecting its quality and service life. Utility Model Content

[0005] The purpose of this utility model is to provide a liquid filling system for an LNG dispenser in order to solve the above-mentioned technical problems.

[0006] To achieve the above objectives, this utility model specifically adopts the following technical solution:

[0007] This utility model provides a liquid filling system for an LNG dispenser, including a liquid outlet pipe connected to the liquid outlet of the LNG dispenser, a filling hose connected to the end of the liquid outlet pipe, a filling gun connected to the filling hose, a return gas pipe assembly, and a precooling pipe assembly.

[0008] The return gas pipeline assembly includes a first return gas pipeline connected to the tank to be filled with liquid, a second return gas pipeline connected to the first return gas pipeline, and the end of the second return gas pipeline connected to the return gas port of the LNG dispenser.

[0009] The precooling pipeline assembly includes a first precooling pipeline and a second precooling pipeline. One end of the first precooling pipeline is connected to the middle of the liquid outlet pipeline, and the other end of the first precooling pipeline is connected to the second return gas pipeline. One end of the second precooling pipeline is connected to the second return gas pipeline, and the other end of the second precooling pipeline is used in conjunction with the filling gun during precooling.

[0010] A liquid flow meter is installed on the liquid outlet pipe located at the rear end of the first precooling pipe, and a gas mass flow meter is installed on the second return gas pipe.

[0011] Specifically, the liquid flow meter is installed on the liquid outlet pipe at the rear end of the first precooling pipe. Even if the valve on the first precooling pipe leaks liquid LNG, the leaked liquid LNG will return to the LNG dispenser along the second return gas pipe and will not be counted in the liquid flow meter on the liquid outlet pipe. This will not cause the liquid flow meter to malfunction and will improve the billing accuracy of the liquid dispensing system.

[0012] In one embodiment, the liquid outlet pipe, the first precooling pipe, and the second return gas pipe constitute a small-circulation precooling pipe system.

[0013] The liquid outlet pipe, the filling hose, the filling gun, the second precooling pipe, and the second return gas pipe constitute the large circulation precooling pipe system.

[0014] In one embodiment, a first control valve is provided at one end of the liquid outlet pipe near the filling hose, and a first one-way valve for backflow is connected in parallel at both ends of the first control valve.

[0015] Specifically, after the refueling gun is completed, the first control valve and the liquid outlet of the refueling gun are closed. At this time, the refueling gun and the refueling hose contain liquid LNG, which vaporizes into gaseous BOG as the temperature rises. The gaseous BOG flows back into the LNG dispenser through the first one-way valve to avoid excessive gas pressure in the refueling gun and the refueling hose, which could cause safety hazards.

[0016] In one embodiment, a control valve is provided on the first precooling pipe.

[0017] In one embodiment, a second one-way valve in the reflux direction is provided on the second precooling pipe, and a large circulation hose is provided at the end of the second precooling pipe. The end of the large circulation hose is provided with a gun socket that cooperates with the filling gun.

[0018] In one embodiment, a third check valve in the return direction is provided on the first return gas pipeline, and a gas phase mass flow meter in the airflow direction is located behind the third check valve. A return hose is provided at the inlet end of the first return gas pipeline, and the end of the return hose is connected to a return gas port that communicates with the return gas port of the liquid to be added tank.

[0019] In one embodiment, a first safety venting assembly is provided on the liquid outlet pipe located at the front end of the first precooling pipe, and a second safety venting assembly is provided on the second return gas pipe. The first safety venting assembly and the second safety venting assembly have the same structure, and their outlets are connected in parallel and communicate with the vent.

[0020] The first safety venting assembly includes a first venting pipe, a second venting pipe, a first safety valve, and an outlet pipe; the first venting pipe and the second venting pipe are connected in parallel between the liquid outlet pipe and the outlet pipe, and both the first venting pipe and the second venting pipe are equipped with manual on / off valves; the first safety valve is located on the second venting pipe.

[0021] Specifically, the first safety venting assembly can prevent the risk of LNG filling pipeline overpressure rupture.

[0022] In one embodiment, the system further includes an interlocking control mechanism, which includes a first pressure detection component and a second pressure detection component. The first pressure detection component is installed on the liquid outlet pipe located at the front end of the first precooling pipe, and the second pressure detection component is installed on the second precooling pipe. Both the first and second pressure detection components are electrically connected to the controller.

[0023] Specifically, during pre-cooling, the controller determines whether there is liquid theft based on whether the pressure difference between the first and second pressure detection components exceeds the standard pressure difference. If the pressure difference does not exceed the standard pressure difference, it proves that there is no liquid theft and it is a normal pre-cooling process, in which case the controller will not charge. If the pressure difference exceeds the standard pressure difference, it proves that there is liquid theft, and then the controller will charge based on the liquid flow meter data.

[0024] In one embodiment, the first pressure detection component includes a first pressure detection tube connected to an outlet pipe located at the front end of the first precooling pipe, a manual control valve is provided on the first pressure detection tube, and a first field pressure gauge and a first remote pressure gauge are separately arranged on the first pressure detection tube located at the rear end of the manual control valve.

[0025] In one embodiment, the second pressure detection assembly includes a second pressure detection tube connected to a second precooling pipe, a manual control valve is provided on the second pressure detection tube, and a second remote pressure gauge is provided on the second pressure detection tube located at the rear end of the manual control valve.

[0026] This solution, through a more scientific and reasonable design of the circulating precooling process, ensures that the LNG dispenser can guarantee sufficient precooling of the pipeline system and core components during the large and small circulating precooling processes. At the same time, it avoids the gas phase flow meter from being affected by the scouring of the LNG cryogenic medium during the precooling process, thus preventing its service life and quality stability from being affected.

[0027] In addition, the precooling process also has a large-circulation precooling anti-theft liquid function.

[0028] The beneficial effects of this utility model are as follows:

[0029] 1. The liquid flow meter is installed on the liquid outlet pipe at the rear end of the first precooling pipe. Even if the valve on the first precooling pipe leaks liquid LNG, the leaked liquid LNG will return to the LNG dispenser along the second return gas pipe and will not be counted in the liquid flow meter on the liquid outlet pipe. This will not cause the liquid flow meter to malfunction and will improve the billing accuracy of the liquid dispensing system.

[0030] 2. This solution, through a more scientific and reasonable design of the circulating precooling process, ensures that the LNG dispenser can guarantee sufficient precooling of the pipeline system and core components during the large and small circulating precooling processes, while avoiding the impact of the LNG cryogenic medium on the service life and quality stability of the gas flow meter during the precooling process.

[0031] 3. The precooling process also has a large-circulation precooling anti-theft liquid function: During precooling, the system determines whether there is leakage based on whether the pressure difference between the first pressure detection component and the second pressure detection component exceeds the standard pressure difference. If the pressure difference does not exceed the standard pressure difference, it proves that there is no liquid theft and it is a normal precooling process. The controller will not charge. If the pressure difference exceeds the standard pressure difference, it proves that there is liquid theft. Then the controller will charge based on the liquid flow meter data.

[0032] 4. After the filling gun is finished, close the first control valve and the liquid outlet of the filling gun. At this time, the filling gun and the filling hose contain liquid LNG. As the temperature rises, it vaporizes into gaseous BOG. ​​The gaseous BOG flows back into the LNG dispenser through the first one-way valve to avoid excessive gas pressure in the filling gun and the filling hose, which may cause safety hazards. Attached Figure Description

[0033] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this utility model and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort.

[0034] Figure 1 This is a schematic diagram of the structure of this utility model;

[0035] Reference numerals: 1-Liquid outlet pipe, 2-Liquid flow meter, 3-First control valve, 4-First check valve, 5-First precooling pipe, 6-First pressure detection component, 7-First safety venting component, 8-Second return gas pipe, 9-Second check valve, 10-Second pressure detection component, 11-Second precooling pipe, 12-First return gas pipe, 13-Second safety venting component, 14-Gas phase mass flow meter. Detailed Implementation

[0036] To make the technical problems, technical solutions, and technical effects of this utility model clearer, the technical solutions of this utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of this utility model. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. The components of the embodiments of this utility model described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0037] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0038] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0039] In the description of the embodiments of this utility model, it should be noted that the terms "inner", "outer", "upper", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the utility model product is usually placed when in use. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0040] Example 1

[0041] like Figure 1 As shown, this embodiment provides a liquid filling system for an LNG dispenser, including a liquid outlet pipe 1 connected to the liquid outlet of the LNG dispenser, a filling hose connected to the end of the liquid outlet pipe 1, a filling gun connected to the filling hose, a return gas pipe assembly, and a precooling pipe assembly.

[0042] The return gas pipeline assembly includes a first return gas pipeline 12 connected to the tank to be filled, a second return gas pipeline 8 connected to the first return gas pipeline, and the end of the second return gas pipeline 8 connected to the return gas port of the LNG dispenser.

[0043] The precooling pipeline assembly includes a first precooling pipeline 5 and a second precooling pipeline 11. One end of the first precooling pipeline 5 is connected to the middle of the liquid outlet pipeline 1, and the other end of the first precooling pipeline 5 is connected to the second return gas pipeline 8. One end of the second precooling pipeline 11 is connected to the second return gas pipeline 8, and the other end of the second precooling pipeline 11 is used in conjunction with the injection gun during precooling.

[0044] A liquid flow meter 2 is installed on the liquid outlet pipe 1 located at the rear end of the first precooling pipe 5, and a gas phase mass flow meter 14 is installed on the second return gas pipe 8.

[0045] Specifically, the liquid flow meter 2 is installed on the liquid outlet pipe 1 located at the rear end of the first precooling pipe 5. Even if the valve on the first precooling pipe 5 leaks liquid LNG, the leaked liquid LNG will return to the LNG dispenser along the second return gas pipe 8 and will not be counted in the gas phase mass flow meter 14 on the second return gas pipe 8. This will not cause the gas phase mass flow meter 14 to malfunction and improve the billing accuracy of the liquid dispensing system.

[0046] Furthermore, compared to the intelligent high-precision LNG refueling metering device disclosed in CN103629525A, this solution, with the liquid flow meter 2 installed after the liquid outlet pipe 1, can effectively prevent discrepancies in liquid volume measurement caused by internal leakage of the valve in the first precooling pipe 5 and the possibility of liquid theft due to human manipulation of the gas phase mass flow meter 14.

[0047] Meanwhile, the gas phase mass flow meter 14 is designed on the first return gas pipeline 12 to increase the accuracy of return gas detection. If it were installed on the second return gas pipeline 8, there would be a problem of inaccurate metering.

[0048] Example 2

[0049] like Figure 1 As shown, this embodiment provides a liquid filling system for an LNG dispenser, including a liquid outlet pipe 1 connected to the liquid outlet of the LNG dispenser, a filling hose connected to the end of the liquid outlet pipe 1, a filling gun connected to the filling hose, a return gas pipe assembly, and a precooling pipe assembly.

[0050] The return gas pipeline assembly includes a first return gas pipeline 12 connected to the tank to be filled, a second return gas pipeline 8 connected to the first return gas pipeline, and the end of the second return gas pipeline 8 connected to the return gas port of the LNG dispenser.

[0051] The precooling pipeline assembly includes a first precooling pipeline 5 and a second precooling pipeline 11. One end of the first precooling pipeline 5 is connected to the middle of the liquid outlet pipeline 1, and the other end of the first precooling pipeline 5 is connected to the second return gas pipeline 8. One end of the second precooling pipeline 11 is connected to the second return gas pipeline 8, and the other end of the second precooling pipeline 11 is used in conjunction with the injection gun during precooling.

[0052] A liquid flow meter 2 is installed on the liquid outlet pipe 1 located at the rear end of the first precooling pipe 5, and a gas phase mass flow meter 14 is installed on the second return gas pipe 8.

[0053] The liquid outlet pipe 1, the first precooling pipe 5, and the second return gas pipe 8 constitute a small circulation precooling pipe system;

[0054] The liquid outlet pipe 1, the filling hose, the filling gun, the second precooling pipe 11, and the second return gas pipe 8 constitute the large circulation precooling pipe system.

[0055] A first control valve 3 is installed at one end of the liquid outlet pipe 1 near the filling hose, and a first one-way valve 4 for backflow is connected in parallel at both ends of the first control valve 3.

[0056] Specifically, after the refueling gun is finished, the first control valve 3 and the liquid outlet of the refueling gun are closed. At this time, the refueling gun and the refueling hose contain liquid LNG, which vaporizes into gaseous CNG as the temperature rises. The gaseous CNG flows back into the LNG dispenser through the first one-way valve 4 to avoid excessive gas pressure in the refueling gun and the refueling hose, which could cause safety hazards.

[0057] Example 3

[0058] This embodiment is a further optimization based on embodiment 2, specifically:

[0059] A control valve is installed on the first precooling pipe 5.

[0060] The second precooling pipe 11 is equipped with a second one-way valve 9 for the return direction, and a large circulation hose is provided at the end of the second precooling pipe 11. The end of the large circulation hose is provided with a plug socket for the injection gun.

[0061] The first return gas pipeline 12 is equipped with a third one-way valve in the return direction. The gas phase mass flow meter 14 is located behind the third one-way valve along the airflow direction. The inlet end of the first return gas pipeline 12 is equipped with a return hose. The end of the return hose is connected to a return gas port that communicates with the return gas port of the liquid to be added tank.

[0062] Example 4

[0063] This embodiment is a further optimization based on embodiment 3, specifically:

[0064] A first safety venting assembly 7 is installed on the liquid outlet pipe 1 located at the front end of the first precooling pipe 5, and a second safety venting assembly 13 is installed on the second return gas pipe 8. The first safety venting assembly 7 and the second safety venting assembly 13 have the same structure, and their outlets are connected in parallel to the vent.

[0065] The first safety venting assembly 7 includes a first venting pipe, a second venting pipe, a first safety valve, and an outlet pipe; the first venting pipe and the second venting pipe are connected in parallel between the liquid outlet pipe 1 and the outlet pipe, and both the first venting pipe and the second venting pipe are equipped with manual switch valves; the first safety valve is located on the second venting pipe.

[0066] Specifically, the first safety venting assembly 7 can prevent the risk of LNG filling pipeline overpressure rupture.

[0067] Example 5

[0068] This embodiment is a further optimization based on embodiment 4, specifically:

[0069] It also includes an interlocking control mechanism, which includes a first pressure detection component 6 and a second pressure detection component 10. The first pressure detection component 6 is installed on the liquid outlet pipe 1 located at the front end of the first precooling pipe 5, and the second pressure detection component 10 is installed on the second precooling pipe 11. Both the first pressure detection component 6 and the second pressure detection component 10 are electrically connected to the controller.

[0070] Specifically, during pre-cooling, the controller determines whether there is liquid theft based on whether the pressure difference between the first pressure detection component 6 and the second pressure detection component 10 exceeds the standard pressure difference. If the pressure difference does not exceed the standard pressure difference, it proves that there is no liquid theft and it is a normal pre-cooling behavior, in which case the controller will not charge. If the pressure difference exceeds the standard pressure difference, it proves that there is liquid theft, and then the controller charges based on the data from the liquid flow meter 2.

[0071] The first pressure detection component 6 includes a first pressure detection tube connected to the liquid outlet pipe located at the front end of the first precooling pipe 5. A manual control valve is provided on the first pressure detection tube, and a first field pressure gauge and a first remote pressure gauge are separately arranged on the first pressure detection tube located at the rear end of the manual control valve.

[0072] In one embodiment, the second pressure detection assembly 10 includes a second pressure detection tube connected to the second precooling pipe 11, a manual control valve is provided on the second pressure detection tube, and a second remote pressure gauge is provided on the second pressure detection tube located at the rear end of the manual control valve.

Claims

1. A liquid dispensing system for an LNG dispenser, characterized in that, It includes an outlet pipe (1) connected to the outlet of the LNG dispenser, a filling hose connected to the end of the outlet pipe (1), a filling gun connected to the filling hose, a return gas pipe assembly, and a precooling pipe assembly. The return gas pipeline assembly includes a first return gas pipeline (12) connected to the tank to be filled, and a second return gas pipeline (8) connected to the first return gas pipeline. The end of the second return gas pipeline (8) is connected to the return gas port of the LNG dispenser. The precooling pipeline assembly includes a first precooling pipeline (5) and a second precooling pipeline (11). One end of the first precooling pipeline (5) is connected to the middle of the liquid outlet pipeline (1), and the other end of the first precooling pipeline (5) is connected to the second return gas pipeline (8). One end of the second precooling pipeline (11) is connected to the second return gas pipeline (8), and the other end of the second precooling pipeline (11) cooperates with the filling gun during precooling. A liquid flow meter (2) is installed on the liquid outlet pipe (1) located at the rear end of the first precooling pipe (5), and a gas phase mass flow meter (14) is installed on the second return gas pipe (8).

2. The LNG dispensing system for an LNG dispenser according to claim 1, characterized in that, The liquid outlet pipe (1), the first precooling pipe (5), and the second return gas pipe (8) constitute a small circulation precooling pipe system; The liquid outlet pipe (1), the filling hose, the filling gun, the second precooling pipe (11), and the second return gas pipe (8) constitute a large-circulation precooling pipe system.

3. A liquid dispensing system for an LNG dispenser according to claim 2, characterized in that, The liquid outlet pipe (1) is provided with a first control valve (3) at one end near the filling hose, and the first control valve (3) is connected in parallel with a first one-way valve (4) for backflow.

4. A liquid dispensing system for an LNG dispenser according to claim 3, characterized in that, A control valve is installed on the first precooling pipe (5).

5. A liquid dispensing system for an LNG dispenser according to claim 4, characterized in that, The second precooling pipe (11) is provided with a second one-way valve (9) in the return direction, and a large circulation hose is provided at the end of the second precooling pipe (11). The end of the large circulation hose is provided with a gun socket that cooperates with the filling gun.

6. A liquid dispensing system for an LNG dispenser according to claim 5, characterized in that, The first return gas pipeline (12) is provided with a third one-way valve in the return direction. The gas phase mass flow meter (14) is located behind the third one-way valve along the airflow direction. The inlet end of the first return gas pipeline (12) is provided with a return hose. The end of the return hose is connected to a return gas port that communicates with the return gas port of the liquid to be added tank.

7. A liquid dispensing system for an LNG dispenser according to claim 6, characterized in that, A first safety venting assembly (7) is provided on the liquid outlet pipe (1) located at the front end of the first precooling pipe (5), and a second safety venting assembly (13) is provided on the second return gas pipe (8). The first safety venting assembly (7) and the second safety venting assembly (13) have the same structure, and their outlets are connected in parallel to the vent. The first safety venting assembly (7) includes a first venting pipe, a second venting pipe, a first safety valve, and an outlet pipe; the first venting pipe and the second venting pipe are connected in parallel between the liquid outlet pipe (1) and the outlet pipe, and both the first venting pipe and the second venting pipe are equipped with manual switch valves; the first safety valve is installed on the second venting pipe.

8. A liquid dispensing system for an LNG dispenser according to claim 7, characterized in that, It also includes an interlocking control mechanism, which includes a first pressure detection component (6) and a second pressure detection component (10). The first pressure detection component (6) is installed on the liquid outlet pipe (1) located at the front end of the first precooling pipe (5), and the second pressure detection component (10) is installed on the second precooling pipe (11). Both the first pressure detection component (6) and the second pressure detection component (10) are electrically connected to the controller.

9. A liquid dispensing system for an LNG dispenser according to claim 8, characterized in that, The first pressure detection component (6) includes a first pressure detection tube connected to the liquid outlet pipe located at the front end of the first precooling pipe (5). A manual control valve is provided on the first pressure detection tube, and a first field pressure gauge and a first remote pressure gauge are separately arranged on the first pressure detection tube located at the rear end of the manual control valve.

10. A liquid dispensing system for an LNG dispenser according to claim 8, characterized in that, The second pressure detection assembly (10) includes a second pressure detection tube connected to the second precooling pipe (11), a manual control valve is provided on the second pressure detection tube, and a second remote pressure gauge is provided on the second pressure detection tube located at the rear end of the manual control valve.

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