JP7413236B2 - LNG fuel transfer system and method - Google Patents

Description

The present invention provides an LNG fuel transfer system and method for transferring LNG (liquefied natural gas) fuel in a supply side fuel tank mounted on a fuel supply ship to a receiving side fuel tank mounted on a fuel receiving ship. Regarding.

In recent years, ships that use LNG (liquefied natural gas) as fuel (hereinafter referred to as "LNG fueled ships") have become popular for the purpose of suppressing nitrogen oxide (NOx) emissions and reducing _CO2 emissions. be. Issues when using LNG as marine fuel include that the composition of LNG differs depending on the place of production, and that the composition of LNG changes as it becomes heavier over time. When the composition of the fuel gas changes, its properties such as its calorific value and methane number change, which can cause abnormal combustion such as engine knocking and misfires. Here, the methane number is an index indicating the resistance value against knocking corresponding to the octane number of a gasoline engine, and is an index evaluated with pure methane as 100 and hydrogen as 0. In order to avoid abnormal combustion as described above, it is considered effective to understand and adjust the properties of fuel gas, such as the methane number.

In view of the above circumstances, Patent Document 1 uses the fact that the composition and density of LNG have a correlation to measure the density of LNG flowing out from the fuel tank in real time, and based on the measured density. It is disclosed that a change in the composition of LNG can be estimated using the following methods. Patent Document 1 further discloses that LNG is supplied from a refueling tank to a fuel tank to adjust the composition of LNG in the fuel tank in accordance with changes in the composition of LNG.

By the way, one method of supplying fuel to an LNG fueled ship is a method in which a fuel supply ship comes alongside the LNG fueled ship and LNG fuel is supplied from the fuel supply ship to the LNG fueled ship (Ship to Ship method). It has been known. Patent Document 2 discloses this type of fuel transfer system.

In Patent Document 2, a supply fuel tank of a fuel supply ship and a receiving fuel tank of a fuel receiving ship that receives supply of LNG fuel are connected by a supply pipe, and a receiving fuel tank and a supply fuel tank are connected by a return pipe. It is disclosed that LNG fuel is pumped from the fuel tank to the receiving fuel tank using a supply pump, and at the same time, unburned vaporized gas generated in the receiving fuel tank is returned to the fuel supply ship through a return pipe and processed by the fuel supply ship. There is.

Japanese Patent Application Publication No. 2014-106098 Japanese Patent Application Publication No. 2014-108759

In order to prevent the methane value of the fuel supplied to the engine from falling below a predetermined lower limit, conventionally, LNG fuel with a sufficiently high methane value was supplied to the fuel tank using BOG (natural evaporative gas) in the fuel tank. Countermeasures have been taken, such as using only LNG as fuel, and removing heavy components that cause a decrease in the methane number when forcedly vaporizing LNG fuel.

However, as LNG-fueled ships become more widespread, it is assumed that in the future they will receive LNG of unspecified composition from an unspecified number of fuel supply ships. There is a possibility that not only LNG with a high methane value but also LNG with a lower methane value than that is supplied to the fuel tank. Therefore, conventional measures may not be sufficient.

In addition, the heavy content removed during forced vaporization of LNG is returned to the fuel tank and accumulated, while the light content, mainly methane, continues to flow out from the fuel tank as BOG. The proportion of heavy LNG remaining in the LNG will continue to increase. In order to prevent the methane value of the fuel (fuel gas) supplied to the engine from falling below a predetermined lower limit value, it is effective to keep the proportion of heavy content of LNG fuel stored in the fuel tank low. it is conceivable that.

The present invention has been made in view of the above circumstances, and its purpose is to propose an LNG fuel transfer system and method that suppresses the proportion of heavy components of LNG fuel in a receiving fuel tank.

An LNG fuel transfer system according to one aspect of the present invention is an LNG fuel transfer system between a first fuel tank and a second fuel tank mounted on a fuel supply ship and a receiving fuel tank mounted on a fuel receiving ship. And,
A fuel supply channel through which liquid LNG fuel flows from the first fuel tank to the receiving fuel tank, and a fuel return channel through which liquid LNG fuel flows from the receiving fuel tank to the second fuel tank can be formed. a liquid sending pipe connecting the first fuel tank, the second fuel tank, and the receiving fuel tank;
a fuel supply state in which the fuel supply channel is effective and the fuel return channel is disabled; and a fuel return state in which the fuel supply channel is disabled and the fuel return channel is effective; A flow path switching device that switches the flow path of the liquid delivery piping,
The liquid sending pipe is set to the fuel return state, and part or all of the liquid LNG fuel remaining in the receiving fuel tank is transferred to the second fuel tank, and then the liquid sending pipe returns the fuel. It is characterized in that the LNG fuel is switched to a supply state and LNG fuel is transferred from the first fuel tank to the receiving fuel tank.

Further, the LNG fuel supply method according to one aspect of the present invention provides a method for supplying LNG fuel between the first fuel tank and the second fuel tank mounted on the fuel supply ship and the receiving fuel tank mounted on the fuel receiving ship. A transportation method,
Transferring some or all of the liquid LNG fuel remaining in the receiving fuel tank to the second fuel tank, and then,
It is characterized in that the LNG fuel stored in the first fuel tank is transferred to the receiving fuel tank.

According to the LNG fuel transfer system and method configured as described above, by removing LNG fuel with a high proportion of heavy content from the receiving fuel tank, an increase in the proportion of heavy content in the receiving fuel tank is suppressed (or eliminated). This allows the proportion of heavy components to be kept low. Therefore, it is possible to prevent the methane value of the fuel sent from the receiving fuel tank to the engine from falling below a predetermined lower limit value, contributing to stable operation of the marine engine.

By providing the second fuel tank separately from the first fuel tank in the fuel supply ship, it is possible to prevent an increase in the proportion of heavy content of the LNG fuel in the first fuel tank, and it is possible to prevent the proportion of heavy content of LNG fuel in the first fuel tank from increasing. It is possible to supply low LNG fuel to the receiving fuel tank.

In addition, since the fuel supply ship can move at sea and come alongside the fuel receiving ship, the fuel receiving ship does not have to come ashore to unload the LNG fuel, which has a high proportion of heavy content, in the receiving fuel tank. It's fine. Furthermore, the fuel supply ship that has recovered the LNG fuel with a high proportion of heavy content can move itself and transport the LNG fuel with a high proportion of heavy content to a storage facility, a consumption facility, or a consumption site. In this way, it is possible to recover and transport LNG fuel with a high proportion of heavy content on the fuel supply ship, so if the fuel receiving vessel is equipped with recovery equipment for LNG fuel with a high proportion of heavy content, It is efficient in comparison.

According to the present invention, it is possible to propose an LNG fuel transfer system and method that suppresses the proportion of heavy components of LNG fuel in a receiving fuel tank.

FIG. 1 is a diagram showing the overall configuration of an LNG fuel transfer system according to an embodiment of the present invention. FIG. 2 is a diagram showing the configuration of the liquid feeding piping. FIG. 3 is a flowchart of an LNG fuel supply method implemented in the LNG fuel transfer system shown in FIG. 1. FIG. 4 is a schematic diagram of an LNG fuel transfer system showing processing example 1 of high-heavy LNG fuel in the second fuel tank. FIG. 5 is a schematic diagram of an LNG fuel transfer system showing a second example of processing high-heavy LNG fuel in the second fuel tank. FIG. 6 is a schematic diagram of an LNG fuel transfer system showing a third example of processing high-heavy LNG fuel in the second fuel tank. FIG. 7 is a schematic diagram of an LNG fuel transfer system showing a processing example 3 of high-heavy LNG fuel in the second fuel tank. FIG. 8 is a schematic diagram of an LNG fuel transfer system showing a modification of processing example 3 for heavy LNG in the second fuel tank.

Hereinafter, one embodiment of the LNG fuel transfer system according to the present invention will be described. The LNG fuel 3 transfer system 11 shown in FIG. configured to be transported. Further, the LNG fuel 3 transfer system 11 is configured to transfer the liquid LNG fuel 3 in the receiving fuel tank 16 to a second fuel tank 40 different from the first fuel tank 13 mounted on the fuel supply ship 12. It is configured. The fuel receiving ship 15 is an LNG fueled ship, and the LNG fuel 3 is used as fuel in the fuel receiving ship 15.

The LNG fuel 3 transfer system 11 includes a liquid sending pipe 14 that connects the first fuel tank 13 and the second fuel tank 40 to the receiving fuel tank 16 .

FIG. 2 is a diagram showing the configuration of the liquid feeding pipe 14. As shown in FIG. 2, the liquid sending pipe 14 includes a receiving pipe 14a, a supply pipe 14b, and a connecting pipe 14c connecting the receiving pipe 14a and the supply pipe 14b.

The receiving side pipe 14a includes a header pipe 150, a return pipe 151 connected to the header pipe 150, and a supply pipe 152 also connected to the header pipe 150. The upstream end of the return pipe 151 is connected to a return pump 52 disposed at the bottom of the receiving fuel tank 16 . The return pipe 151 is provided with a first return valve 41 . The downstream end of the supply pipe 152 is located at the lower part of the receiving fuel tank 16, and the supply pipe 152 is provided with a first supply valve 42.

The supply pipe 14b includes a header pipe 140, a supply pipe 141 connected to the header pipe 140, and a return pipe 142 also connected to the header pipe 140. The upstream end of the supply pipe 141 is connected to the supply pump 17 disposed at the bottom of the first fuel tank 13 . Further, the supply pipe 141 is provided with a second supply valve 43 . The downstream end of the return pipe 142 is located at the lower part of the second fuel tank 40, and the return pipe 142 is provided with a second return valve 44.

The connection pipe 14c connects the header pipe 150 of the receiving side pipe 14a and the header pipe 140 of the supply side pipe 14b. The connection portion between the connection pipe 14c and the receiving side pipe 14a, and the connection portion between the connection pipe 14c and the supply side pipe 14b are configured to be connectable/disconnectable. Note that the connecting pipe 14c may be omitted and the header pipe 150 of the receiving side pipe 14a and the header pipe 140 of the supply side pipe 14b may be directly connected.

In the liquid sending pipe 14 having the above configuration, there is a fuel supply passage F1 through which liquid LNG fuel flows from the first fuel tank 13 to the receiving fuel tank 16, and a fuel supply passage F1 through which liquid LNG fuel flows from the receiving fuel tank 16 to the second fuel tank 40. A fuel return flow path F2 through which fuel flows can be formed. Specifically, by closing the first return valve 41 and the second return valve 44 and opening the first supply valve 42 and the second supply valve 43, the supply pipe 141, the header pipe 140, the connection pipe 14c, A fuel supply flow path F1 consisting of a header pipe 150 and a supply pipe 152 is formed. Further, the first supply valve 42 and the second supply valve 43 are closed, and the first return valve 41 and the second return valve 44 are opened, so that the return pipe 151, the header pipe 150, the connecting pipe 14c, the header pipe 140 , and a return pipe 142, a fuel return flow path F2 is formed. In this way, the first return valve 41, the first supply valve 42, the second supply valve 43, and the second return valve 44 function as a flow path switching device D that switches the flow path of the liquid sending pipe 14.

Due to the action of the flow path switching device D, the liquid sending pipe 14 has a fuel supply state in which the fuel supply flow path F1 is effective and the fuel return flow path F2 is ineffective, and a fuel supply state in which the fuel return flow path F2 is active and the fuel return flow path F2 is inactive. A fuel return state in which the supply flow path F1 is disabled can be selectively established. When the supply pump 17 operates while the liquid sending pipe 14 is in the fuel supply state, liquid LNG fuel is transferred from the first fuel tank 13 to the receiving fuel tank 16 through the fuel supply passage F1. Further, when the return pump 52 operates while the liquid sending pipe 14 is in the fuel return state, liquid LNG fuel is transferred from the receiving fuel tank 16 to the second fuel tank 40 through the fuel return passage F2.

Returning to FIG. 1, the LNG fuel 3 transfer system 11 further includes an air supply pipe 18 for returning the vaporized gas 3a from the receiving fuel tank 16 to the fuel supply ship 12.

The upstream end of the air supply pipe 18 is connected to the upper part of the receiving fuel tank 16 . The downstream end of the air supply pipe 18 is connected to the upper part of the first fuel tank 13 and the inlet of a compressor 20 provided in the fuel supply ship 12 .

Part or all of the vaporized gas 3a returned from the receiving fuel tank 16 through the air supply pipe 18 is compressed by the compressor 20. The outlet of the compressor 20 is connected to the inlet of the gas incinerator 21 and the gas supply port of the engine 22, respectively. Thereby, the vaporized gas 3a compressed by the compressor 20 is supplied to each of the gas incinerator 21 and the engine 22. The gas incineration device 21 and the engine 22 are both mounted on the fuel supply ship 12 and serve as the vaporized gas processing device 19.

The gas incinerator 21 burns the vaporized gas 3a supplied from the compressor 20, and releases the burned gas into the atmosphere from an exhaust gas port. The engine 22 is used, for example, to generate propulsive force for the fuel supply ship 12 or to generate power for power generation. The engine 22 uses the vaporized gas 3a supplied from the compressor 20 as part of its fuel, and this burned gas is released into the atmosphere. In this way, the vaporized gas processing device 19 provided in the fuel supply ship 12 does not directly release the vaporized gas 3a returned to the fuel supply ship 12 via the air supply pipe 18 into the atmosphere, but instead treats the vaporized gas 3a. It is configured to use the fuel as fuel before releasing it into the atmosphere.

Next, a method for supplying LNG fuel 3 using the transfer system 11 having the above configuration will be explained. FIG. 3 is a flowchart of a method for supplying LNG fuel 3 implemented in the LNG fuel 3 transfer system 11 shown in FIG.

As shown in FIGS. 1 to 3, first, the fuel supply ship 12 is brought alongside the fuel receiving ship 15, and the liquid sending pipe 14 is connected between the first fuel tank 13 and the second fuel tank 40 and the receiving fuel tank 16. (Step S1), and connect the receiving fuel tank 16 and the compressor 20 with the air supply pipe 18.

In the initial state, each of the valves 41 to 44 constituting the flow path switching device D is closed. First, by opening the first return valve 41 and the second return valve 44 of the flow path switching device D, the fuel return flow path F2 of the liquid sending pipe 14 is enabled and the fuel supply flow path F1 is disabled. It is assumed that fuel is being returned. Then, when the return pump 52 is operated, the LNG fuel 3 remaining in the receiving fuel tank 16 is transferred from the receiving fuel tank 16 to the second fuel tank 40 through the liquid sending pipe 14 (step S2). Hereinafter, for convenience, the LNG fuel 3 remaining in the receiving fuel tank 16 before the receiving fuel tank 16 receives the supply of LNG fuel 3 that has not become heavier will be referred to as "residual LNG fuel 3r." Here, all or a part of the remaining LNG fuel 3r in the receiving fuel tank 16 may be transferred. The residual LNG fuel 3r in the receiving fuel tank 16 has a high proportion of heavy components, and as a result, the second fuel tank 40 stores LNG fuel 3b having a high proportion of heavy components. Hereinafter, the LNG fuel 3 with a high proportion of heavy content stored in the second fuel tank 40 will be referred to as "high-heavy LNG fuel 3b" for convenience.

When the return pump 52 is stopped and the transfer of the residual LNG fuel 3r is finished, the first return valve 41 and the second return valve 44 of the flow path switching device D are closed, and the first supply valve 42 and the second return valve 44 are closed. By opening the supply valve 43, the liquid sending pipe 14 is switched to a fuel supply state in which the fuel return passage F2 is disabled and the fuel supply passage F1 is enabled. Then, when the supply pump 17 is operated, the LNG fuel 3 is transferred from the first fuel tank 13 to the receiving fuel tank 16 through the liquid sending pipe 14 (step S3). When the LNG fuel is transferred from the first fuel tank 13 to the receiving fuel tank 16, the compressor 20 may be operated and the vaporized gas 3a in the receiving fuel tank 16 may be transferred to the compressor 20 through the air supply pipe 18.

When the supply pump 17 is stopped and the transfer of the LNG fuel 3 is finished, the liquid feeding pipe 14 is disconnected (step S4), and the air feeding pipe 18 is disconnected. This allows the fuel supply ship 12 to leave the side of the fuel receiving ship 15. Finally, the high-heavy LNG fuel 3b stored in the second fuel tank 40 is processed (step S5).

The high-heavy LNG fuel 3b stored in the second fuel tank 40 is consumed within the fuel supply ship 12, or transported by the fuel supply ship 12 to a consumption area and unloaded, and then processed.

FIG. 4 is a diagram showing a transfer system 11A for the LNG fuel 3, which shows a first processing example of the high-heavy LNG fuel 3b in the second fuel tank 40. In the LNG fuel 3 transfer system 11A illustrated in FIG. A fuel supply pipe 57 is provided. The high-heavy LNG fuel 3b sent from the second fuel tank 40 to the dual fuel boiler 48 is used as fuel for the dual fuel boiler 48. Note that the dual fuel boiler 48 is an example of a combustion device mounted on the fuel supply ship 12. In addition to the dual fuel boiler 48, examples of the combustion device mounted on the fuel supply ship 12 include a GCU (Gas Combustion Unit), a GCU-combined IGG (Inert Gas Generator), and the like.

FIG. 5 is a schematic diagram of the LNG fuel 3 transfer system 11B showing a second processing example of the high-heavy LNG fuel 3b in the second fuel tank 40. The LNG fuel 3 transfer system 11B illustrated in FIG. It is configured to unload cargo to 49. Here, a supply pipe 143 is connected to the header pipe 140 of the supply side pipe 14b. The upstream end of the supply pipe 143 is connected to a liquid pump 58 disposed at the bottom of the second fuel tank 40 . Further, the supply pipe 143 is provided with a third supply valve 60 .

A loading pipe 45 is connected to the header pipe 140 of the supply side pipe 14b. The downstream end of this unloading pipe 45 is located within the LNG storage facility 49. In this way, a cargo unloading channel F3 is formed in the liquid sending pipe 14, through which the LNG fuel stored in the second fuel tank 40 flows from the second fuel tank 40 to the LNG storage facility 49 provided on land.

When the liquid sending pump 58 is operated with the second supply valve 43 and the second return valve 44 closed and the third supply valve 60 opened, high-heavy LNG fuel flows into the second fuel tank 40. 3b is transferred from the second fuel tank 40 to the LNG storage facility 49 of the LNG base through the unloading channel F3. The high-heavy LNG fuel 3b sent to the LNG storage facility 49 is used, for example, to adjust the calorific value of city gas at the LNG terminal.

FIG. 6 is a schematic diagram of the LNG fuel 3 transfer system 11C showing a third processing example of the high-heavy LNG fuel 3b in the second fuel tank 40. In the LNG fuel 3 transfer system 11C illustrated in FIG. 6, a supply pipe 141, a return pipe 142, and a supply pipe 143 are connected to the header pipe 140 of the supply side pipe 14b. The upstream end of the supply pipe 143 is connected to a liquid pump 58 disposed at the bottom of the second fuel tank 40 .

The second fuel tank 40 stores in advance LNG fuel 3 that has not become heavier. Here, the LNG fuel 3 with a high proportion of heavy content sent from the receiving fuel tank 16 is mixed (however, the amount of LNG fuel 3 that has not been made heavy is the LNG fuel with a high proportion of heavy content). 3). The inside of the second fuel tank 40 is agitated by means such as recirculation operation of a pump, and the stored LNG fuel 3c is homogenized. In this way, the methane number of the LNG fuel 3c in the second fuel tank 40 decreases somewhat by mixing the LNG fuel 3 with a high proportion of heavy content. For example, there are engines that can use LNG fuel with a relatively low methane number, such as diesel cycle dual fuel engines. The LNG fuel 3c stored in the second fuel tank 40 may be supplied to a fuel tank of a fuel receiving ship equipped with an engine capable of using such LNG fuel with a low methane value.

Therefore, as shown in FIG. 7, in the LNG fuel 3 transfer system 11C, liquid LNG fuel flows from the second fuel tank 40 to the second receiving fuel tank 50 mounted on the second fuel receiving vessel 65. It is configured to be able to form a second fuel supply flow path F4. By the supply side pipe 14b provided on the fuel supply ship 12, the receiving side pipe 14a' provided on the second fuel receiving ship 65, and the connecting pipe 14c connecting the supply side pipe 14b and the receiving side pipe 14a'. , and a liquid feeding pipe 14'. The receiving side pipe 14a provided in the second fuel receiving ship 65 has a header pipe 160 and a supply pipe 162 connected to the header pipe 160. The downstream end of the supply pipe 162 is located at the lower part of the second receiving fuel tank 50, and the supply pipe 162 is provided with a fourth supply valve 66. In the liquid sending pipe 14' having the above configuration, the second fuel supply channel F4 is formed by the supply pipe 143, the header pipe 140, the connecting pipe 14c, the header pipe 160, and the supply pipe 162.

When the liquid feeding pump 58 is operated with the second supply valve 43 and the second return valve 44 closed and the third supply valve 60 and the fourth supply valve 66 opened, the inside of the second fuel tank 40 is The LNG fuel 3c is transferred to the second receiving fuel tank 50 through the second fuel supply flow path F4. In this way, the LNG fuel 3c in the second fuel tank 40, which has a somewhat lower methane value than the LNG fuel 3 in the first fuel tank 13, is used as fuel in the second fuel receiving ship 65.

In the above transfer system 11C, the LNG fuel 3 having a high proportion of heavy content is transferred to the second fuel tank 40 so that the methane number of the mixed LNG fuel 3c stored in the second fuel tank 40 becomes the target methane number. The inflow amount may be adjusted. In this case, as shown in FIG. 8, the methane number (or methane number index) of the LNG fuel 3 sent from the receiving fuel tank 16 through the liquid sending pipe 14 is measured using the methane number measuring device 54. . Subsequently, the amount of heavy LNG fuel 3b flowing into the second fuel tank 40 is calculated based on the measured value of the methane number and the target methane number. Then, the adjustment device 55 operates so that the calculated inflow amount of high-heavy LNG fuel 3b flows into the second fuel tank 40. In this way, the methane number of the LNG fuel 3c in the second fuel tank 40 after being mixed with the high-heavy LNG fuel 3b can be adjusted.

(Summary)
As explained above, the LNG fuel 3 transfer system 11, 11A to 11C of the present embodiment is installed in the first fuel tank 13 and the second fuel tank 40 mounted on the fuel supply ship 12 and on the fuel receiving ship 15. A system for transferring LNG fuel 3 between a received fuel tank 16 and a receiving fuel tank 16,
A fuel supply passage F1 through which liquid LNG fuel 3 flows from the first fuel tank 13 to the receiving fuel tank 16, and a fuel return passage through which liquid LNG fuel 3 flows from the receiving fuel tank 16 to the second fuel tank 40. A liquid supply pipe 14 that connects the first fuel tank 13 and the second fuel tank 40 to the receiving fuel tank 16 so as to form F2;
There is a fuel supply state in which the fuel supply channel F1 is valid and the fuel return channel F2 is disabled, and a fuel return state in which the fuel supply channel F1 is disabled and the fuel return channel F2 is enabled. A flow path switching device D that switches the flow path of the liquid pipe 14,
The liquid sending pipe 14 is set to the fuel return state, and part or all of the liquid LNG fuel 3 remaining in the receiving fuel tank 16 is transferred to the second fuel tank 40, and then the liquid sending pipe 14 is set to the fuel return state. It is characterized in that the LNG fuel 3 is transferred from the first fuel tank 13 to the receiving fuel tank 16 by switching to the state.

In addition, the LNG fuel 3 supply method according to one aspect of the present invention includes the first fuel tank 13 and the second fuel tank 40 mounted on the fuel supply ship 12 and the receiving fuel tank 16 mounted on the fuel receiving ship 15. A method for transferring LNG fuel 3 between
Part or all of the liquid LNG fuel 3 remaining in the receiving fuel tank 16 is transferred to the second fuel tank 40, and then the LNG fuel 3 stored in the first fuel tank 13 is transferred to the receiving fuel tank 16. It is characterized by being transferred to.

According to the LNG fuel 3 transfer system 11, 11A to 11C and the LNG fuel 3 supply method configured as described above, before the LNG fuel 3 is supplied to the receiving fuel tank 16, the heavy The LNG fuel 3 with a high proportion of quality is forcibly discharged. Thereby, more of the LNG fuel 3, which has not become heavier, can be supplied to the receiving fuel tank 16. In addition, by removing the LNG fuel 3 with a high proportion of heavy content from the receiving fuel tank 16, the proportion of heavy content in the receiving fuel tank 16 to which the LNG fuel 3 that has not become heavy has been supplied increases. It is possible to suppress (or eliminate) the ratio of heavy components to a low level. Therefore, even if the methane number of the LNG fuel 3, which is not heavy enough, is not high enough, the methane number of the fuel sent from the receiving fuel tank 16 to the engine can be prevented from falling below a predetermined lower limit value, and the marine engine This can contribute to stable operation.

By providing the second fuel tank 40 in the fuel supply ship 12 separately from the first fuel tank 13, it is possible to prevent an increase in the proportion of heavy content of the LNG fuel 3 in the first fuel tank 13, In the fuel receiving ship 15, the receiving fuel tank 16 is replenished with LNG fuel 3 having a sufficiently low proportion of heavy content, so that fuel with a high methane value can be supplied to the engine.

In addition, since the fuel supply ship 12 can move on the sea and come alongside the fuel receiving ship 15, the fuel receiving ship 15 can unload the LNG fuel 3 with a high proportion of heavy content in the receiving fuel tank 16. Do not land on the ground. Furthermore, the fuel supply ship 12 that has recovered the LNG fuel 3 with a high proportion of heavy content can move itself and transport the LNG fuel 3 with a high proportion of heavy content to a storage facility, a consumption facility, or a consumption site. . In this way, since the LNG fuel 3 with a high proportion of heavy content can be recovered and transported by the fuel supply ship 12, the LNG fuel 3 with a high proportion of heavy content can be recovered on land or on the fuel receiving vessel 15. It is more efficient compared to the case where equipment is provided.

Further, the LNG fuel 3 transfer system 11A according to the embodiment described above transfers the LNG fuel (high-heavy content LNG fuel 3b) stored in the second fuel tank 40 to a combustion device (for example, It is further provided with a heavy fuel supply pipe 57 for feeding to the dual fuel boiler 48).

In this way, the heavy LNG fuel 3b generated in the fuel receiving ship 15 can be consumed in the fuel supplying ship 12.

In addition, in the LNG fuel 3 transfer system 11B according to the above embodiment, the liquid sending pipe 14 transports the LNG fuel (high-heavy content LNG fuel 3b) stored in the second fuel tank 40 from the second fuel tank 40 to land. It has an unloading channel F3 that flows to the provided LNG storage facility 49.

In this way, the high-heavy LNG fuel 3b generated in the fuel receiving ship 15 can be transported by the fuel receiving ship 15 to the LNG storage facility 49 on land and consumed in the LNG storage facility 49. Therefore, it becomes possible to use the high-heavy LNG fuel 3b not only as a marine fuel but also for other purposes.

In addition, in the LNG fuel 3 transfer system 11C according to the above embodiment, the second fuel tank 40 contains the LNG fuel 3c stored in advance and the LNG fuel (high-heavy LNG fuel 3b) transferred from the receiving fuel tank 16. The liquid LNG fuel 3c is configured to mix the liquid LNG fuel 3c from the second fuel tank 40 to the second receiving fuel tank 50 mounted on the second fuel receiving ship 65. Two fuel supply channels F4 can be formed.

With this configuration, in the second fuel tank 40, the LNG fuel 3c stored in advance and the LNG fuel with a high proportion of heavy content transferred from the receiving fuel tank 16 (high content LNG fuel 3b) are mixed. Thus, it is possible to realize a transfer method in which the LNG fuel 3c is transferred from the second fuel tank 40 to the second receiving fuel tank 50 mounted on the second fuel receiving ship 65. The LNG fuel 3c stored in the second fuel tank 40 can then be used by the second fuel receiving ship 65 equipped with an engine capable of using LNG fuel with a relatively low methane value.

Furthermore, in the above transfer system 11C, a methane number measuring device 54 for measuring the methane number of the LNG fuel (heavy content LNG fuel 3b) transferred from the receiving fuel tank 16 to the second fuel tank 40, and a methane number measuring device 54 are provided. Based on the measured value of the device 54 and a predetermined target methane number, the LNG fuel (high-heavy It may further include an adjustment device 55 for adjusting the amount of LNG fuel 3b).

With this configuration, the methane number of the heavy LNG fuel 3b transferred from the receiving fuel tank 16 to the second fuel tank 40 is measured, and based on the measured value and a predetermined target methane number, the second fuel tank 40 The amount of the heavy LNG fuel 3b transferred to the second fuel tank 40 can be adjusted so that the LNG fuel 3c stored in the second fuel tank 40 has the target methane value. By adjusting the methane number of the LNG fuel 3c stored in the second fuel tank 40 to the target methane number in this way, the LNG fuel 3 with a known methane number can be supplied to the second receiving fuel tank 50.

Although the preferred embodiments of the present invention have been described above, the present invention may include modifications to the specific structure and/or functional details of the above embodiments without departing from the spirit of the present invention. . The above configuration can be modified as follows, for example.

For example, in the above embodiment, processing examples 1 to 3 of the high-heavy LNG fuel 3b in the second fuel tank 40 are shown, but at least two of these processing examples 1 to 3 may be combined.

Further, for example, in the above embodiment, the switching operation of each valve included in the flow path switching device D may be performed by an operator, but the switching operation of each valve included in the flow path switching device D is performed by one control device. It may be configured to be controlled by. In this case, a control device is mounted on the fuel supply ship 12, and the driving parts of each valve included in the flow path switching device D are electrically connected to this control device by wire or wirelessly. Then, by executing a program stored in advance in the processor, the control device controls each valve included in the flow path switching device D so that the switching operation is performed in accordance with the flow of the above-described LNG fuel 3 supply method. Control.

Further, for example, in the above embodiment, the flow path switching device D includes the valves 41 to 44, but the specific configuration of the flow path switching device D is not limited to this embodiment. One of the first supply valve 42 and the second supply valve 43 may be omitted. Similarly, one of the first return valve 41 and the second return valve 44 may be omitted. Furthermore, the flow path switching device D may include elements other than the valves 41 to 44.

3: LNG fuel 11, 11A to C: Transfer system 12: Fuel supply ship 13: First fuel tank 14, 14': Liquid sending pipe 15: Fuel receiving ship 16: Receiving fuel tank 18: Air sending pipe 40: Second Fuel tank 48: Dual fuel boiler (an example of a combustion device)
49: LNG storage equipment 50: Second receiving fuel tank 54: Methane value measuring device 55: Adjusting device 57: Heavy fuel supply pipe 65: Second fuel receiving ship D: Flow path switching device F1: Fuel supply flow Channel F2: Fuel return channel F3: Unloading channel F4: Second fuel supply channel

Claims (8)

An LNG fuel transfer system between a first fuel tank and a second fuel tank mounted on a fuel supply ship and a receiving fuel tank mounted on a fuel receiving ship, the system comprising:
A fuel supply channel through which liquid LNG fuel flows from the first fuel tank to the receiving fuel tank, and a fuel return channel through which liquid LNG fuel flows from the receiving fuel tank to the second fuel tank can be formed. a liquid sending pipe connecting the first fuel tank, the second fuel tank, and the receiving fuel tank;
a fuel supply state in which the fuel supply channel is effective and the fuel return channel is disabled; and a fuel return state in which the fuel supply channel is disabled and the fuel return channel is effective; A flow path switching device that switches the flow path of the liquid delivery piping,
The liquid sending pipe is set to the fuel return state, and part or all of the liquid LNG fuel remaining in the receiving fuel tank is transferred to the second fuel tank, and then the liquid sending pipe returns the fuel. LNG fuel is switched to a supply state and transferred from the first fuel tank to the receiving fuel tank;
LNG fuel transfer system. Further comprising a heavy fuel supply pipe that sends the LNG fuel stored in the second fuel tank to a combustion device installed in the fuel supply ship.
The LNG fuel transfer system according to claim 1. The liquid sending pipe has a loading flow path through which the LNG fuel stored in the second fuel tank flows from the second fuel tank to an LNG storage facility provided on land.
The LNG fuel transfer system according to claim 1 or 2. The second fuel tank is configured to mix LNG fuel stored in advance and LNG fuel transferred from the receiving fuel tank,
The liquid sending pipe can form a second fuel supply channel through which liquid LNG fuel flows from the second fuel tank to a second receiving fuel tank mounted on a second fuel receiving ship.
The LNG fuel transfer system according to any one of claims 1 to 3. a methane number measuring device that measures the methane number of LNG fuel flowing from the receiving fuel tank to the second fuel tank;
Based on the measured value of the methane number measuring device and a predetermined target methane number, the amount of LNG fuel flowing into the second fuel tank so that the LNG fuel stored in the second fuel tank has the target methane number. further comprising an adjustment device for adjusting the
The LNG fuel transfer system according to claim 4. A method for transferring LNG fuel between a first fuel tank and a second fuel tank mounted on a fuel supply ship and a receiving fuel tank mounted on a fuel receiving ship, the method comprising:
Transferring some or all of the liquid LNG fuel remaining in the receiving fuel tank to the second fuel tank, and then,
transferring the LNG fuel stored in the first fuel tank to the receiving fuel tank;
Method of transferring LNG fuel. Mixing LNG fuel stored in advance and LNG fuel transferred from the receiving fuel tank in the second fuel tank,
transferring LNG fuel from the second fuel tank to a second receiving fuel tank mounted on a second fuel receiving ship;
The method for transferring LNG fuel according to claim 6. Measuring the methane number of LNG fuel transferred from the receiving fuel tank to the second fuel tank,
Adjusting the amount of LNG fuel transferred to the second fuel tank based on the measured value and a predetermined target methane number so that the LNG fuel stored in the second fuel tank has the target methane number.
The method for transferring LNG fuel according to claim 7.

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