A shore-based LNG natural gas refueling system

Abstract

The utility model discloses a kind of shore-based LNG natural gas filling system, including tank car mechanism, cryogenic submerged pump mechanism, booster and filling ship party, connect three pipelines from tank car mechanism place, respectively as liquid phase pipeline, booster pipeline and gas phase pipeline;Gas phase pipeline other end is connected to filling ship party by hose;Booster pipeline other end is connected to gas phase pipeline;Cold BOG in filling ship party can enter liquid phase pipeline and cryogenic submerged pump mechanism and precooling;The connecting place of liquid phase pipeline and tank car mechanism is arranged and can be to the sweep port of liquid phase pipeline inner residual liquid purging.This application uses the BOG of cold state in ship party fuel tank to precool filling equipment, part BOG is introduced into liquid phase pipeline, in turn through filling process pipeline, cryogenic submerged pump returns tank booster lower liquid, realizes precooling to filling system while reducing ship fuel tank pressure, entire process does not produce loss;Shorten overall operation time, improve operation efficiency.

Description

Technical Field

[0001] This utility model relates to the field of natural gas refueling technology, specifically to an onshore LNG natural gas refueling system. Background Technology

[0002] The Wuhu Yangtze River LNG bunkering station is the first shore-based vessel bunkering station on inland waterways in China. With a berth length of 133 meters, it can accommodate a maximum of one 5,000-ton inland waterway motorized vessel for bunkering operations. The designed bunkering rate is 40 Nm³ / h, with an annual designed bunkering capacity of 30,200 tons. The bunkering process at the Wuhu Yangtze River LNG bunkering station is as follows: After an LNG-powered vessel arrives at the station, the ship's bunkering port is connected to the bunkering metering skid, and the tank truck's bunkering port is connected to the bunkering pump skid via hoses. The LNG in the tank truck is pressurized by a cryogenic submersible pump and then transported through the bunkering metering skid to the ship's LNG fuel tank, thus completing the bunkering process. LNG bunkering is similar to diesel bunkering. LNG is a cryogenic liquid, typically at -162℃. When it exchanges heat with the external environment, it produces boil-off gas (BOG), causing the equipment pressure to rise continuously. When the equipment reaches its design pressure, it must be safely vented.

[0003] Currently, ship refueling volume is measured using flow meters, while tanker unloading volume is measured by weighing the tankers twice. A comparative analysis of ship refueling and tanker unloading volumes shows that, under conditions of non-continuous refueling, the loss per ship is approximately 500 kg. Analysis of the existing problems reveals that this loss arises from two main sources:

[0004] First, there are losses incurred during the pre-cooling process of the refueling equipment;

[0005] The Wuhu Yangtze LNG refueling station is still in the early stages of operation, and refueling operations are not yet fully operational. At the start of each refueling phase, the pipelines, pump tanks, flow meters, and other refueling equipment need to be pre-cooled. When the cold LNG in the tank trucks encounters the ambient-temperature refueling equipment, it generates a large amount of BOG (Boiled Air Gas), which is the gas produced when LNG is passively heated and vaporized. Some of this BOG returns to the tank truck's vapor phase to pressurize it. However, under normal circumstances, the tank trucks arrive fully hydrated, resulting in a high LNG level and a very limited vapor phase space, which can only accommodate a very small amount of BOG. ​​If too much BOG returns to the tank truck's vapor phase, exceeding the tank truck's safety valve activation pressure, it may cause LNG leakage, posing a hazard to on-site operators and the refueling equipment.

[0006] Second, the loss caused by the release of residual liquid in the filling equipment;

[0007] According to the manufacturer's design documents, after refueling, the designed purging points can only purge the residual LNG in the ship-shore connecting hose and the ship-tank truck connecting hose; they cannot purge the LNG pipelines in the intermediate refueling system; and a large amount of residual LNG remains in the refueling skid, metering skid, and the LNG pipeline connecting the two skids that cannot be purged and metered. Based on the volume calculation of the refueling skid, metering skid, and LNG liquid phase pipeline (25.7m, 100mm in diameter), this residual LNG can reach 400kg, resulting in losses. Utility Model Content

[0008] The technical problem to be solved by this utility model is: how to reduce natural gas loss in onshore LNG refueling stations.

[0009] To solve the above-mentioned technical problems, this utility model provides the following technical solution:

[0010] An onshore LNG refueling system includes a tank truck mechanism, a cryogenic submersible pump mechanism, a booster, and a refueling vessel. Three pipelines are connected from the tank truck mechanism: a liquid phase pipeline, a booster pipeline, and a gas phase pipeline.

[0011] One end of the liquid phase pipeline is connected to the tank truck mechanism, and the other end is connected to the refueling vessel via a hose. The cryogenic submersible pump mechanism is installed on the liquid phase pipeline.

[0012] One end of the gas phase pipeline is connected to the tank truck mechanism, and the other end is connected to the refueling vessel via a hose; one end of the pressurization pipeline is connected to the tank truck mechanism, and the other end is connected to the gas phase pipeline, and a pressurizer is installed on the pressurization pipeline.

[0013] The cold BOG inside the bunkering vessel can enter the liquid phase pipeline and cryogenic submersible pump mechanism for pre-cooling.

[0014] The connection between the liquid phase pipeline and the tank truck mechanism is provided with a purge port that can purge the residual liquid in the liquid phase pipeline.

[0015] This application utilizes the cold BOG (Boiler Gas) in the ship's fuel tank to pre-cool the refueling equipment. Part of the BOG is introduced into the liquid phase pipeline and then sequentially returned to the tank truck for pressurization (re-pressurization) via the refueling process pipeline and cryogenic submersible pump. This process reduces the pressure in the ship's fuel tank while simultaneously pre-cooling the refueling system. The entire process is lossless. It can shorten the overall operation time and improve operational efficiency while avoiding losses.

[0016] As a further embodiment of this utility model: the cryogenic submersible pump mechanism includes a first cryogenic submersible pump and a second cryogenic submersible pump, wherein both the first cryogenic submersible pump and the second cryogenic submersible pump are connected to the liquid phase pipeline.

[0017] As a further embodiment of this utility model: the first cryogenic submersible pump and the second cryogenic submersible pump are respectively provided with liquid phase valve three and liquid phase valve four at the connection between them and the liquid phase pipeline.

[0018] As a further embodiment of this utility model: the tanker mechanism includes a first tanker, a second tanker, and a third tanker arranged in parallel, and all three sets of parallel tankers can be connected to the bunkering vessel via liquid phase pipelines and gas phase pipelines.

[0019] As a further embodiment of this utility model: the first tank truck is connected to the first liquid phase pipeline, the first pressurization pipeline and the first gas phase pipeline, and the other end of the first liquid phase pipeline is connected to the bunkering vessel. The cryogenic submersible pump mechanism is connected to the first liquid phase pipeline, and the first liquid phase pipeline is provided with liquid phase valve one, liquid phase valve two, liquid phase valve nine, liquid phase valve ten, check valve one and liquid phase valve eleven in sequence from the side of the first tank truck toward the bunkering vessel.

[0020] As a further embodiment of this utility model: the other end of the first pressurization pipeline is connected to the first gas phase pipeline, and a pressurization valve one, a pressurization valve two, and a pressurizer are provided on the first pressurization pipeline.

[0021] As a further embodiment of this utility model: the other end of the first gas phase pipeline is connected to the refueling vessel, and gas phase valve one, gas phase valve three, gas phase valve two, gas phase valve eight, check valve two and gas phase valve nine are sequentially provided on the side of the first gas phase pipeline from the first tank truck toward the refueling vessel.

[0022] As a further embodiment of this utility model: the second tanker is connected to a second liquid phase pipeline, a second pressurization pipeline and a second gas phase pipeline, the other end of the second liquid phase pipeline is connected to a first liquid phase pipeline; the other end of the second pressurization pipeline is connected to a second pressurization pipeline, and the other end of the second gas phase pipeline is connected to a first gas phase pipeline.

[0023] As a further embodiment of this utility model: the third tanker is connected to a third liquid phase pipeline, a third pressurization pipeline and a third gas phase pipeline, the other end of the third liquid phase pipeline is connected to a first liquid phase pipeline; the other end of the third pressurization pipeline is connected to a second pressurization pipeline, and the other end of the third gas phase pipeline is connected to the first gas phase pipeline.

[0024] Compared with the prior art, the beneficial effects of this utility model are:

[0025] First, this application utilizes the cold BOG in the ship's fuel tank to pre-cool the refueling equipment. Part of the BOG is introduced into the liquid phase pipeline, and then sequentially returned to the tank truck for pressurization (re-pressurization) via the refueling process pipeline and the cryogenic submersible pump. This reduces the pressure in the ship's fuel tank while simultaneously pre-cooling the refueling system. The entire process is lossless. It can shorten the overall operation time and improve operation efficiency while avoiding losses.

[0026] Secondly, this application changes the purging method to fully purge the residual liquid in the refueling system; when the refueling is about to end, the tank truck outlet valve is closed in advance, and a purging point is designed at the inlet of the refueling skid at the liquid phase pipeline connected to the tank truck. Nitrogen gas is used to purge in reverse towards the ship side to purge the residual liquid in the pump pool and refueling process pipeline to the ship and measure it. There are two purging paths, and the residual liquid in the refueling equipment is fully purged through the two paths. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of an onshore LNG refueling system according to an embodiment of the present invention;

[0028] Figure 2 This is the pre-cooling route for a cold-state BOG according to an embodiment of the present invention;

[0029] Figure 3 This is the purging route for the liquid phase pipeline in an embodiment of the present invention;

[0030] Explanation of reference numerals in the attached figures:

[0031] 1. First tank truck; 2. Second tank truck; 3. Third tank truck; 4. First cryogenic submersible pump; 5. Second cryogenic submersible pump; 7. Bunkering vessel; 8. Booster;

[0032] 10. Liquid phase valve one; 11. Liquid phase valve two; 12. Liquid phase valve three; 13. Liquid phase valve four; 14. Liquid phase valve five; 15. Liquid phase valve six; 16. Liquid phase valve seven; 17. Liquid phase valve eight; 18. Liquid phase valve nine; 19. Liquid phase valve ten; 110. Check valve one; 111. Liquid phase valve eleven;

[0033] 20. Pressure boosting valve one; 21. Pressure boosting valve two; 22. Pressure boosting valve three; 23. Pressure boosting valve four; 24. Pressure boosting valve five;

[0034] 30. Vapor phase valve one; 31. Vapor phase valve two; 32. Vapor phase valve three; 33. Vapor phase valve four; 34. Vapor phase valve five; 35. Vapor phase valve six; 36. Vapor phase valve seven; 37. Vapor phase valve eight; 38. Check valve two; 39. Vapor phase valve nine;

[0035] 40. Valve 1; 41. Valve 2. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below in conjunction with the embodiments of this utility model. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0037] Reference Figure 1 An onshore LNG refueling system includes a first tank truck 1, a second tank truck 2, and a third tank truck 3 arranged in parallel, and also includes a first cryogenic submersible pump 4, a second cryogenic submersible pump 5, and a booster 8 connected to the three tank trucks.

[0038] Reference Figure 1 The first tanker 1 is connected to three pipelines: the first liquid phase pipeline, the first pressurization pipeline, and the first gas phase pipeline, all of which are rigid pipes.

[0039] The other end of the first liquid phase pipeline is finally connected to the bunkering vessel 7, and two pipelines branch off from the first liquid phase pipeline and are respectively connected to the first cryogenic submersible pump 4 and the second cryogenic submersible pump 5; liquid phase valve 10 and liquid phase valve 21 are sequentially installed in the direction of the first cryogenic submersible pump 4 and the second cryogenic submersible pump 5 in the first liquid phase pipeline; liquid phase valve 312 and liquid phase valve 413 are respectively installed at the inlet end of the first cryogenic submersible pump 4 and the second cryogenic submersible pump 5 in the first liquid phase pipeline facing the bunkering vessel 7; liquid phase valve 918, liquid phase valve 1019, check valve 110 and liquid phase valve 111 are sequentially installed in the first liquid phase pipeline of the first cryogenic submersible pump 4 and the second cryogenic submersible pump 5 in the first liquid phase pipeline facing the bunkering vessel 7; and finally, the liquid phase pipeline between liquid phase valve 111 and the bunkering vessel 7 is a flexible hose.

[0040] The other end of the first pressurization pipeline is connected to the first gas phase pipeline, and a booster 8 is installed on the first pressurization pipeline. A booster valve 1 20 and a booster valve 21 are sequentially provided on the first gas phase pipeline between the booster 8 and the first tank car 1. A gas phase valve 32 is provided on the first gas phase pipeline between the booster 8 and the first gas phase pipeline.

[0041] The other end of the first gas phase pipeline is finally connected to the refueling vessel 7, and gas phase valve 1 30, gas phase valve 2 31, gas phase valve 32, gas phase valve 8 37, check valve 2 38 and gas phase valve 9 39 are sequentially installed on the first gas phase pipeline, wherein the booster 8 is used to pressurize the gas phase pipeline.

[0042] Reference Figure 1 The second tanker 2 is connected to three pipelines: the second liquid phase pipeline, the second pressurization pipeline, and the second gas phase pipeline.

[0043] The second liquid phase pipeline has two connection methods. The first method is to directly connect it to the first liquid phase pipeline, and then connect it to the first cryogenic submersible pump 4, the second cryogenic submersible pump 5, and the bunkering vessel 7 through the first liquid phase pipeline. The second method is to directly connect it to the first cryogenic submersible pump 4, and then connect the first cryogenic submersible pump 4 to the bunkering vessel 7 through the first liquid phase pipeline. A liquid phase valve 6 15 is installed at the inlet of the second liquid phase pipeline, and a liquid phase valve 5 14 is installed at the connection between the second liquid phase pipeline and the first cryogenic submersible pump 4.

[0044] The other end of the second pressurization pipeline is directly connected to the first pressurization pipeline, and the first pressurization pipeline is used to pressurize the second gas phase pipeline. A pressurization valve 23 is also provided at the connection position between the second pressurization pipeline and the second tank car 2.

[0045] The other end of the second gas phase pipeline is split into two and connected to the first gas phase pipeline and the first cryogenic submersible pump 4 respectively. Gas phase valve 4 33 and gas phase valve 7 36 are provided on the second gas phase pipeline between the first cryogenic submersible pump 4 and the second tank truck 2.

[0046] Reference Figure 1 The third tanker truck 3 is connected to three pipelines, namely the third liquid phase pipeline, the third pressurization pipeline, and the third gas phase pipeline.

[0047] The third liquid phase pipeline has two connection methods. The first method is to directly connect it to the first liquid phase pipeline, and then connect it to the first cryogenic submersible pump 4, the second cryogenic submersible pump 5, and the bunkering vessel 7 through the first liquid phase pipeline. The second method is to directly connect it to the second cryogenic submersible pump 5, and then connect the second cryogenic submersible pump 5 to the bunkering vessel 7 through the first liquid phase pipeline. A liquid phase valve 7 16 is installed at the inlet of the third liquid phase pipeline, and a liquid phase valve 8 17 is installed at the connection between the third liquid phase pipeline and the second cryogenic submersible pump 5.

[0048] The other end of the third pressurization pipeline is directly connected to the first pressurization pipeline, and the first pressurization pipeline is used to pressurize the third gas phase pipeline. A pressurization valve 24 is also provided at the connection position between the third pressurization pipeline and the third tank car 3.

[0049] The other end of the third gas phase pipeline is split into two and connected to the first gas phase pipeline and the second cryogenic submersible pump 5 respectively. Gas phase valve 5 34 and gas phase valve 6 35 are provided on the third gas phase pipeline between the second cryogenic submersible pump 5 and the third tank truck 3.

[0050] The first liquid phase pipeline and the first gas phase pipeline, which are quickly connected to the bunkering vessel 7, can also be connected, and valve 40 and valve 41 are installed between them for control.

[0051] Reference Figure 2After the LNG-powered vessel berths and completes relevant safety inspections, the ship's side return gas valve is opened to recover and reuse the cold BOG from the ship's fuel tanks for pre-cooling of the refueling equipment (i.e., cryogenic submersible pumps, liquid phase pipelines, flow meters, etc.). Figure 2 (The diagram uses the third tanker truck 3 and the second cryogenic submersible pump 5 as an example; the bold black lines represent the LNG and BOG flow directions.) The process control flow is as follows:

[0052] Vapor phase valve 9 39 - Check valve 2 38 - Liquid phase valve 9 18 - Liquid phase valve 2 11 - Liquid phase valve 8 17 - Second cryogenic submersible pump 5 - Vapor phase valve 6 35 - Pressure booster valve 3 22 - Pressure booster valve 5 24.

[0053] This application ingeniously introduces this portion of BOG (Boiled Air Gas) into the liquid phase pipeline, sequentially passing through the refueling process pipeline and the cryogenic submersible pump before returning to the tank truck for pressurization (re-pressurization). This simultaneously reduces the pressure in the ship's fuel tanks and pre-cools the refueling system. The entire process is lossless, and the gas ultimately returns to the tank truck for pressurization. The tank truck pressure rises slowly, never exceeding its safe starting pressure. Actual verification shows that with a ship's return gas volume of approximately 200 kg, the pump sump inlet temperature can be pre-cooled to approximately -100°C, and the liquid phase pipeline temperature to approximately -110°C.

[0054] Reference Figure 3 This application changes the purging method to fully purge the remaining liquid in the refueling system. When refueling is about to end (about 300 kg remaining in the tanker), the tanker outlet valve is closed in advance, and the nitrogen manual valve is opened on site (the nitrogen manual valve is located in front of the tanker, which is added externally and is not shown in the figure). By designing the refueling skid inlet purging point in the liquid phase pipeline connected between the liquid phase valve 716 and the third tanker 3, nitrogen is used to purge in reverse towards the ship side to purge the remaining liquid in the pump pool and refueling process pipeline to the ship side and measure it.

[0055] At this point, the remaining liquid in the filling equipment is thoroughly purged through two paths. The process control method is as follows (the diagram uses the third tanker truck 3 and the second cryogenic submersible pump 5 as an example; the bold black lines indicate the LNG and BOG flow directions, i.e., the purging paths):

[0056] First route: Liquid phase valve 7 16 — Liquid phase valve 8 17 — Second cryogenic submersible pump 5 — Liquid phase valve 4 13 — Liquid phase valve 9 18 — Liquid phase valve 10 19 — Liquid phase valve 11 111 — Refueling ship 7.

[0057] Second route: Liquid phase valve 7 16 —— Liquid phase valve 2 11 —— Liquid phase valve 9 18 —— Liquid phase valve 10 19 —— Liquid phase valve 11 111 —— Refueling ship 7.

[0058] This application proposes to change the purging method to fully purge the residual liquid in the refueling system; actual verification shows that the above two measures can reduce the LNG loss per ship by about 350 kg.

[0059] In 2023, a total of 165 LNG refuelings were carried out, generating economic benefits of approximately RMB 346,500 (calculated based on an LNG price of RMB 6,000 per ton).

[0060] With the further expansion of the bunkering market, the frequency of bunkering at the Wuhu Yangtze River LNG bunkering station will increase further. Based on an annual bunkering capacity of 30,200 tons and a bunkering volume of 10 tons per vessel, the number of bunkering trips per year could reach 3,000. Therefore, it can be inferred that the future annual economic benefit could reach approximately 0.35 tons * 3,000 trips * 6,000 yuan / ton ≈ 6.3 million yuan.

[0061] Currently, due to the limited number of LNG-powered vessels on the Yangtze River, refueling stations along the river generally suffer from discontinuous refueling operations and significant wear and tear on repeatedly pre-cooled equipment. The Wuhu Yangtze River LNG Refueling Station, as the refueling station with the highest refueling frequency and volume along the Yangtze River, has taken the lead in solving the problem of natural gas refueling losses, playing a leading and exemplary role in the development of the entire industry. It has effectively reduced the amount of safe natural gas emissions and significantly mitigated the environmental impact.

[0062] The above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.

Claims

1. An onshore LNG refueling system, characterized in that, It includes a tank truck mechanism, a cryogenic submersible pump mechanism, a booster (8) and a refueling vessel (7), and three pipelines are connected from the tank truck mechanism, namely a liquid phase pipeline, a booster pipeline and a gas phase pipeline; One end of the liquid phase pipeline is connected to the tank truck mechanism, and the other end is connected to the refueling vessel (7) via a hose. The cryogenic submersible pump mechanism is installed on the liquid phase pipeline. One end of the gas phase pipeline is connected to the tank truck mechanism, and the other end is connected to the refueling vessel via a hose (7); one end of the pressurization pipeline is connected to the tank truck mechanism, and the other end is connected to the gas phase pipeline, and a pressurizer (8) is installed on the pressurization pipeline; The cold BOG inside the refueling vessel (7) can enter the liquid phase pipeline and the cryogenic submersible pump mechanism for pre-cooling; The connection between the liquid phase pipeline and the tank truck mechanism is provided with a purge port that can purge the residual liquid in the liquid phase pipeline.

2. The onshore LNG refueling system according to claim 1, characterized in that: The cryogenic submersible pump mechanism includes a first cryogenic submersible pump (4) and a second cryogenic submersible pump (5), wherein both the first cryogenic submersible pump (4) and the second cryogenic submersible pump (5) are connected to the liquid phase pipeline.

3. The onshore LNG refueling system according to claim 2, characterized in that: The first cryogenic submersible pump (4) and the second cryogenic submersible pump (5) are respectively equipped with liquid phase valve three (12) and liquid phase valve four (13) at the connection between them and the liquid phase pipeline.

4. The onshore LNG refueling system according to claim 1, characterized in that: The tanker mechanism includes a first tanker (1), a second tanker (2), and a third tanker (3) arranged in parallel, and all three sets of parallel tankers can be connected to the bunkering vessel (7) through liquid phase pipelines and gas phase pipelines.

5. The onshore LNG refueling system according to claim 4, characterized in that: The first tank truck (1) is connected to the first liquid phase pipeline, the first pressurization pipeline and the first gas phase pipeline. The other end of the first liquid phase pipeline is connected to the bunkering vessel (7). The cryogenic submersible pump mechanism is connected to the first liquid phase pipeline. The first liquid phase pipeline is provided with liquid phase valve one (10), liquid phase valve two (11), liquid phase valve nine (18), liquid phase valve ten (19), check valve one (110) and liquid phase valve eleven (111) in sequence from the side of the first tank truck (1) toward the bunkering vessel (7).

6. The onshore LNG refueling system according to claim 5, characterized in that: The other end of the first pressurization pipeline is connected to the first gas phase pipeline, and a pressurization valve one (20), a pressurization valve two (21) and a pressurizer (8) are provided on the first pressurization pipeline.

7. The onshore LNG refueling system according to claim 5, characterized in that: The other end of the first gas phase pipeline is connected to the refueling vessel (7), and gas phase valve one (30), gas phase valve three (32), gas phase valve two (31), gas phase valve eight (37), check valve two (38) and gas phase valve nine (39) are sequentially provided on the side of the first gas phase pipeline from the first tank truck (1) toward the refueling vessel (7).

8. The onshore LNG refueling system according to claim 5, characterized in that: The second tanker (2) is connected to the second liquid phase pipeline, the second pressurization pipeline and the second gas phase pipeline. The other end of the second liquid phase pipeline is connected to the first liquid phase pipeline; the other end of the second pressurization pipeline is connected to the second pressurization pipeline, and the other end of the second gas phase pipeline is connected to the first gas phase pipeline.

9. The onshore LNG refueling system according to claim 5, characterized in that: The third tanker (3) is connected to the third liquid phase pipeline, the third pressurization pipeline and the third gas phase pipeline. The other end of the third liquid phase pipeline is connected to the first liquid phase pipeline; the other end of the third pressurization pipeline is connected to the second pressurization pipeline and the other end of the third gas phase pipeline is connected to the first gas phase pipeline.

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