JP6698725B2 - Gas lubrication system for ships using LNG, and method of operating ships using LNG - Google Patents

Description

The present disclosure, the gas lubrication system for blowing out gas from the hull of the ship utilizing LNG, and a method of operating a ship utilizing LNG.

  BACKGROUND ART As a type of ship that uses the output from an engine to navigate, an LNG carrier that carries LNG that is a low-temperature liquid fuel, an LNG fuel ship that uses vaporized LNG, and the like are known. For example, in an LNG carrier, boil-off gas (BOG) in a tank that stores LNG is used as fuel for an engine. Especially in a dual fuel engine, when increasing the engine output, in addition to boil-off gas, the vaporized gas generated by forcibly evaporating part of the LNG stored in the tank is used together Fuel supply is increased.

  By the way, as a technique for reducing the frictional resistance acting on the hull during navigation, a gas lubrication system is known in which gas is jetted from an outlet provided in a hull to cover the outer surface of the hull with bubbles. For example, Patent Document 1 discloses a gas lubrication system capable of equalizing the amount of air blown from the air outlet even when the hull is inclined due to rolling during navigation. Further, Patent Document 2 discloses a gas lubrication system capable of controlling the amount of air blown out from an outlet in accordance with the amount of change in draft when the amount of load on the hull changes.

JP 2012-166704 A JP, 2013-091376, A

  When a gas lubrication system such as the one described above is applied to a ship with a large draft, the water pressure at the air outlet at which the gas is blown out increases, so the energy consumption for blowing out the gas against the water pressure increases. Will end up. As a result, it may be difficult to fully enjoy the energy-saving effect due to the reduction of frictional resistance due to the gas lubrication system.

At least one embodiment of the present invention has been made in view of the above circumstances, the gas body lubrication of marine utilizing capable of reducing LNG consumption energy for the supply of gas to the blow-out opening disposed in a hull An object of the present invention is to provide a system and a ship operating method using LNG.

(1) In order to solve the above problems, a gas lubrication system for a ship using LNG according to at least one embodiment of the present invention,
A gas lubrication system for a ship to use the L NG,
The LNG flowing through the LNG line that is provided on the gas supply line for supplying gas to the outlet provided in the hull of the ship and that is connected to the LNG tank of the LNG carrier and the gas supply line A gas supply line extending through the interior of the heat exchanger of an LNG vaporizer for vaporizing LNG to the outlet, comprising a heat exchanger configured to exchange heat with the gas;
A first blower provided on the gas supply line between the heat exchanger and the air outlet,
Equipped with.

  With configuration (1) above, when LNG flowing through the LNG line is vaporized in the heat exchanger, the gas flowing through the gas supply line is cooled by exchanging heat with the LNG. By lowering the temperature of the gas flowing through the gas supply line in this manner, energy consumption for supplying the gas to the blowout port provided in the hull of the ship is reduced.

  Further, according to the above configuration (1), the gas flowing through the gas supply line passing through the inside of the heat exchanger is cooled by exchanging heat with the LNG flowing through the LNG line. As a result, the temperature of the gas supplied to the first blower provided between the heat exchanger and the outlet (that is, on the downstream side of the heat exchanger) on the gas supply line decreases, so that the energy consumption of the first blower is reduced. It can be effectively reduced.

(2) In some embodiments, in the configuration of (1) above,
An LNG forced evaporation line provided in parallel with the gas supply line,
The heat exchanger is
A medium that exchanges heat with the LNG flowing through the LNG line is switchable between the gas flowing through the gas supply line and the heat medium flowing through the LNG forced evaporation line.

According to the configuration of (2) above, the flow of gas toward the outlet in the gas supply line is stopped by exchanging heat between the LNG flowing in the LNG line and the heat medium flowing in the forced evaporation line. Can continue to vaporize LNG.

(3) In some embodiments, in the configuration of (2) above,
A circulation device provided in the LNG forced evaporation line for circulating the heat medium;
A heater provided in the LNG forced evaporation line for heating the heat medium,
Equipped with.

  According to the above configuration (3), in the forced evaporation line, the heat medium heated by the heater is circulated by the circulation device. As a result, when the LNG flowing through the LNG line exchanges heat with the heat medium flowing through the forced evaporation line, the heat medium flowing through the forced evaporation line is continuously and stably supplied with heat energy to ensure proper vaporization of the LNG. You can do it.

( 4 ) In some embodiments, in any one of the configurations (1) to (3) above,
An exhaust line that branches from the gas supply line downstream of the heat exchanger and that communicates with an exhaust port provided on the low pressure side of the blowout port is provided.

According to the above configuration ( 4 ), the gas flowing through the gas supply line is discharged from the discharge port through the discharge line, so that the ejection of the gas from the blowout port can be stopped. Since the discharge port is provided on the lower pressure side than the blowout port, less energy is consumed to blow out the gas than the blowout port. Therefore, energy consumption can be suppressed even in the situation where the ejection of gas from the air outlet is stopped.

( 5 ) In some embodiments, in the configuration of ( 4 ) above,
Of the gas supply line, on the upstream side from the branch point with the discharge line, a parallel line provided in parallel with the gas supply line,
A second blower installed on the parallel line and having a smaller output than the first blower,
Equipped with.

According to the above configuration ( 5 ), the gas can be discharged through the discharge line by the second blower provided on the parallel line. Since the second blower has a smaller output than the first blower, it is possible to further suppress the energy consumption required for discharging.

( 6 ) In some embodiments, in any one of the above configurations ( 1 ) to ( 5 ),
A bypass line is provided in parallel with the gas supply line and bypasses the heat exchanger.

According to the configuration of ( 6 ) above, by guiding the gas flowing through the gas supply line to the bypass line, it is possible to avoid pressure loss that occurs when the gas passes through the heat exchanger. By allowing the gas to flow by such a bypass line so as to bypass the heat exchanger, it is possible to suppress energy consumption when operating the gas lubrication system while stopping the vaporization of LNG in the LNG vaporizer.

( 7 ) In some embodiments, in any one of the configurations ( 1 ) to ( 6 ) above,
A cooling gas supply line branched from the downstream side of the heat exchanger in the gas supply line and communicating with at least one of an intake passage of an engine mounted on the LNG carrier or an engine room in which the engine is housed.

According to the above configuration ( 7 ), the gas cooled by exchanging heat with the LNG in the heat exchanger is supplied to at least one of the intake passage of the engine and the engine room via the cooling gas supply line. As a result, the engine power can be reduced by cooling the intake air of the engine, or the engine room cooling power can be reduced.

( 8 ) In some embodiments, in any one of the configurations ( 1 ) to ( 7 ) above,
The gas supply line is configured to supply exhaust gas of an engine mounted on the LNG carrier to the air outlet as the gas.

According to the above configuration ( 8 ), the exhaust gas of the engine is supplied to the gas supply line. As a result, since exhaust gas having high temperature and pressure is introduced into the heat exchanger, LNG can be efficiently vaporized and the heat exchanger can be downsized. Further, by introducing exhaust gas having a high pressure into the gas supply line, it is possible to reduce the energy consumption required for ejecting the gas from the air outlet.

( 9 ) In order to solve the above-mentioned problems, a ship operating method utilizing LNG according to at least one embodiment of the present invention,
Flowing a gas through a gas supply line toward an outlet provided on the hull of the LNG carrier,
Vaporizing the LNG flowing in an LNG line connected to an LNG tank of the LNG carrier by heat exchange with the gas flowing in the gas supply line,
At least using the vaporized gas obtained by vaporization of the LNG as fuel, operating the engine of the LNG carrier,
Equipped with.

According to the method of ( 9 ) above, by causing the gas to flow through the gas supply line toward the air outlet provided in the hull of the ship, the gas ejected from the air outlet generates bubbles that cover the outer surface of the hull. The frictional resistance of the hull during navigation can be reduced. On the other hand, LNG flowing through the LNG line becomes vaporized gas by heat exchange with the gas flowing through the gas supply line, and is supplied to the engine. At this time, the gas flowing through the gas supply line is cooled by exchanging heat with the LNG and the temperature thereof is lowered, so that the energy consumption for supplying the gas to the air outlet provided in the hull of the ship can be reduced.

( 10 ) In some embodiments, in the above method ( 9 ),
A step of vaporizing the LNG by exchanging heat between the heat medium flowing through the LNG forced evaporation line provided in parallel with the gas supply line and the LNG when the supply of the gas to the outlet is stopped. Equipped with.

According to the method of the above ( 10 ), even when the supply of gas to the air outlet is stopped, the LNG vaporization can be continued by exchanging heat between the LNG flowing in the LNG line and the heat medium flowing in the forced evaporation line. ..

( 11 ) In some embodiments, in the method of ( 9 ) or ( 10 ) above,
When the ejection of the gas from the outlet is stopped, the gas that has undergone heat exchange with the LNG is discharged through a discharge line branched from the gas supply line to a lower pressure side than the outlet. Ejecting to the outlet.

According to the above method ( 11 ), when the ejection of gas from the air outlet is stopped, the gas that has undergone heat exchange with LNG is exhausted from the exhaust port through the exhaust line. Since the discharge port is provided on the lower pressure side than the blowout port, less energy is required to blow out the gas than the blowout port.

( 12 ) In some embodiments, in the method according to any one of ( 9 ) to ( 11 ) above,
The method includes the step of supplying the gas, which is heat-exchanged with the LNG, to at least one of an intake passage of an engine mounted on the ship or an engine room in which the engine is housed.

According to the above method ( 12 ), the gas cooled by exchanging heat with LNG in the heat exchanger is supplied to at least one of the intake passage and the engine room of the engine. As a result, the engine power can be reduced by cooling the intake air of the engine, or the engine room cooling power can be reduced.

( 13 ) In some embodiments, in the method according to any one of ( 9 ) to ( 12 ) above,
Flowing the exhaust gas of the engine of the ship as the gas to the gas supply line.

According to the above method ( 13 ), the exhaust gas of the engine is supplied to the gas supply line. As a result, exhaust gas with high temperature and pressure is introduced into the heat exchanger, so that LNG can be efficiently vaporized and downsizing of the heat exchanger can be performed. Further, by introducing exhaust gas having a high pressure into the gas supply line, it is possible to reduce energy consumption required for ejecting gas from the air outlet.

( 14 ) In some embodiments, in the method according to any one of ( 9 ) to ( 13 ) above,
The first blower provided in the gas supply line on the downstream side of the heat exchanger that performs heat exchange between the LNG and the gas ejects the gas heat-exchanged with the LNG from the outlet. With steps.

According to the above method ( 14 ), the gas cooled by exchanging heat with the LNG is ejected from the blowout port by the first blower provided in the gas supply line on the downstream side of the heat exchanger. It As a result, the temperature of the gas supplied to the first blower decreases, so that the energy consumption of the first blower can be effectively reduced.

( 15 ) In some embodiments, in the method according to any one of ( 9 ) to ( 14 ) above,
When the engine is operated by using only the boil-off gas from the LNG tank as a fuel, the method includes a step of bypassing a heat exchanger that performs heat exchange between the LNG and the gas and supplying the gas to the air outlet.

According to the above method ( 15 ), when the engine is operated by using only the boil-off gas from the LNG tank as fuel, the vaporization of LNG flowing through the LNG line is stopped. In such a case, the gas flowing through the gas supply line bypasses the heat exchanger and is guided to the air outlet. As a result, the pressure loss that occurs when the gas flowing through the gas supply line passes through the heat exchanger can be avoided, so that the energy consumption can be further suppressed.

According to at least one embodiment of the present invention, the gas body lubrication system for a ship utilizing capable of reducing LNG consumption energy for the supply of gas to the blow-out opening disposed in a hull, and utilizes LNG A method of operating a ship can be provided.

It is a schematic diagram which shows the internal structure of the LNG carrier provided with the LNG vaporization apparatus which concerns on 1st Embodiment of this invention. It is a flowchart which shows the operating method of the LNG carrier of FIG. 1 for every process. It is a schematic diagram which shows the internal structure of the LNG carrier provided with the LNG vaporization apparatus which concerns on 2nd Embodiment of this invention. 4 is a flowchart showing a method of operating the LNG carrier of FIG. 3 for each step. It is a schematic diagram which shows the internal structure of the LNG carrier provided with the LNG vaporization apparatus which concerns on 3rd Embodiment of this invention. 6 is a flowchart showing a method of operating the LNG carrier of FIG. 5 for each step. It is a schematic diagram which shows the internal structure of the LNG carrier provided with the LNG vaporization apparatus which concerns on 4th Embodiment of this invention. 8 is a flowchart showing the operation method of the LNG carrier of FIG. 7 for each step. It is a schematic diagram which shows the internal structure of the LNG carrier provided with the LNG vaporization apparatus which concerns on 5th Embodiment of this invention. It is a schematic diagram which shows the internal structure of the LNG carrier provided with the LNG vaporization apparatus which concerns on 6th Embodiment of this invention. It is a schematic diagram which shows the internal structure of the LNG carrier provided with the LNG vaporizer concerning a reference technique.

Hereinafter, some embodiments of the present invention will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative positions, etc. of the components described as the embodiments or shown in the drawings are not intended to limit the scope of the present invention thereto, but are merely illustrative examples. Absent.
For example, the expressions representing relative or absolute arrangements such as "in a certain direction", "along a certain direction", "parallel", "orthogonal", "center", "concentric", or "coaxial" are strict. In addition to representing such an arrangement, it also represents a state of relative displacement, or a state of relative displacement with an angle or distance such that the same function can be obtained.
Further, for example, an expression representing a shape such as a quadrangle or a cylindrical shape does not only represent a shape such as a quadrangle or a cylindrical shape in a geometrically strict sense, but also an uneven portion or A shape including a chamfered portion and the like is also shown.
On the other hand, the expressions “comprising”, “comprising”, “comprising”, “including”, or “having” one element are not exclusive expressions excluding the existence of other elements.

<Reference technology>
Before describing specific embodiments of the present invention, the present specification describes a reference technique as a premise thereof. FIG. 11: is a schematic diagram which shows the internal structure of the LNG carrier 1 which is an example of the ship which utilizes LNG provided with the LNG vaporizer 10 which concerns on a reference technique.
In the following description, the LNG carrier 1 will be described as an example of a ship that uses LNG, but at least one embodiment of the present invention is also applicable to other ships that use LNG, such as LNG fuel lines. Is.

  The LNG carrier 1 is a ship for carrying LNG which is a low temperature liquid fuel. The LNG carrier 1 is equipped with an LNG tank 2 capable of storing LNG to be transported, and the LNG tank 2 stores LNG in a high-pressure liquid state. The LNG tank 2 has a substantially spherical shape, and the liquid surface of the liquid LNG stored inside is filled with the boil-off gas 4 formed by evaporation of LNG.

  The LNG carrier 1 is equipped with an engine 6 that uses LNG vaporized gas as fuel, as a power source for navigation. A boil-off gas supply line 8 connected to the upper portion of the LNG tank 2 is connected to the intake side of the engine 6, and the boil-off gas in the LNG tank 2 can be supplied to the engine 6 as fuel.

The engine 6 is a dual fuel engine, and when the engine output is increased, in addition to the boil-off gas supplied through the boil-off gas supply line 8, one of the LNG stored in the LNG tank 2 is added as necessary. The vaporized gas generated by forcibly evaporating the portion is configured to be supplied. Specifically, a part of the LNG stored in the LNG tank 2 is introduced into the LNG vaporizer 10 by the LNG line 12 connected to the lower portion of the LNG tank 2, and the LNG vaporized by the LNG vaporizer 10 is generated. The vaporized gas of is capable of being supplied to the intake side of the engine 6 via the vaporized gas supply line 14.
In the following description, a dual fuel engine will be described as an example of the engine 6, but the engine 6 can include all engines that use vaporized LNG as fuel.

  The LNG vaporizer 10 includes a heat exchanger 18 configured to exchange heat between the heat medium flowing in the LNG forced evaporation line 16 and the LNG flowing in the LNG line 12. A pump 20, which is a circulation device for circulating the heat medium in the closed circuit, and a heater 22 for heating the heat medium are installed on the LNG forced evaporation line 16. In the LNG vaporizer 10, the heat medium heated by the heater 22 circulates in the LNG forced evaporation line 16 by the pump 20, so that the heat exchanger 18 heats the LNG flowing in the LNG line 12 to generate vaporized gas. ..

  A compressor 24 for compressing the boil-off gas supplied via the boil-off gas supply line 8 and the vaporized gas supplied from the vaporized gas supply line 14 is arranged on the intake side of the engine 6.

  Further, the LNG carrier 1 is equipped with a gas lubrication system 26 for reducing the frictional resistance acting on the hull during navigation. The gas lubrication system 26 acts on the hull in flight by covering the outer surface of the hull with bubbles by injecting gas toward the water from an outlet 28 provided in the hull (not shown) of the LNG carrier 1. Reduces frictional resistance.

  The position of the outlet 28 in the hull of the LNG carrier 1 may be arbitrary, but the outlet 28 is provided at the bottom of the ship, for example.

  The gas lubrication system 26 has a gas supply line 30 for supplying gas to the air outlet 28. The gas supply line 30 connects the intake port 32 for taking in the gas and the air outlet 28 provided in the hull. In the present embodiment, the intake port 32 is provided so as to open to the inside of the ship or the deck at atmospheric pressure, and is configured to be able to take in air in the atmosphere as a gas that can be ejected from the outlet port 28.

  A first blower 34 is installed in the gas supply line 30 as a blower for sending the gas taken into the gas supply line 30. The first blower 34 is a blower device that can be driven by electric power supplied from a power supply source (not shown). When the first blower 34 is driven, gas (air from standby) is taken in from the intake 32, and the gas flows through the gas supply line 30 toward the outlet 28.

  As described above, in the LNG carrier 1 according to the reference technique, the LNG vaporization device 10 and the gas lubrication system 26 are mounted as mutually independent systems (separate systems). In such an LNG carrier 1, when the energy (electric power) consumed by the first blower 34 when operating the gas lubrication system 26 becomes large, the gas lubrication system 26 sufficiently enjoys the energy saving effect by reducing the friction resistance. May be difficult to do. In particular, in a ship with a large draft such as the LNG carrier 1, the water pressure at the air outlet 28 from which the gas is blown out is high, so the energy consumption for blowing out the gas against the water pressure tends to increase.

  The problem in such a reference technique can be suitably solved in each embodiment described below. In addition, in each embodiment described below, common reference numerals are given to configurations corresponding to the above-described reference technology, and duplicate description will be omitted unless otherwise specified.

<First Embodiment>
FIG. 1 is a schematic diagram showing an internal structure of an LNG carrier 1 including an LNG vaporizer 10 according to a first embodiment of the present invention.

  The LNG vaporizer 10 includes a heat exchanger 36 configured to exchange heat between the gas flowing through the gas supply line 30 of the gas lubrication system 26 and the LNG flowing through the LNG line 12. In the above-described reference technique, the gas supply line 30 of the gas lubrication system 26 and the LNG line 12 of the LNG vaporizer 10 are configured as independent systems (separate systems), but in the present embodiment, the gas lubrication is performed. The gas supply line 30 of the system 26 and the LNG line 12 of the LNG vaporizer 10 are incorporated into a common heat exchanger 36 to form an integrated heat exchange system. That is, the heat exchanger 36 includes the gas supply line 30 of the gas lubrication system 26 and the LNG line 12 of the LNG vaporizer 10. In other words, the gas supply line 30 extends through the inside of the heat exchanger 36 of the LNG vaporization device 10 to the outlet 28.

  As described above, in the present embodiment, the LNG vaporizer 10 and the gas lubrication system 26 are constructed as a substantially integrated system, and the LNG forced evaporation line 16 required for vaporizing LNG by the reference technique, The pump 20 and the heater 22 can be eliminated. Therefore, the system size is small, and good design freedom can be obtained.

  FIG. 2 is a flowchart showing the operation method of the LNG carrier 1 of FIG. 1 for each step.

  In the LNG carrier 1, according to the operating state of the gas lubrication system 26, the gas is flown through the gas supply line 30 toward the outlet 28 provided in the hull (step S10). The gas flow in the gas supply line 30 is formed by operating the first blower 34 provided in the gas supply line 30. The gas flowing through the gas supply line 30 is jetted out into the water from the air outlet 28 as necessary, thereby covering the outer surface of the hull with bubbles and reducing the frictional resistance acting on the hull during navigation.

  In the LNG line 12, the LNG introduced from the LNG tank 2 to the LNG vaporizer 10 is vaporized by exchanging heat with the gas flowing through the gas supply line 30 in the heat exchanger 36 according to the output state of the engine 6. (Step S11). That is, in the heat exchanger 36, the LNG flowing through the LNG line 12 is heated by the gas flowing through the gas supply line 30 to generate vaporized gas.

In the heat exchange of step S11, the gas flowing through the gas supply line 30 is cooled by the LNG flowing through the LNG line 12. Since the gas cooled by the heat exchanger 36 is sent to the first blower 34 in this way, energy consumption in the first blower 34 is reduced.

  The vaporized gas generated by the heat exchanger 36 is sent to the engine 6 via the vaporized gas supply line 14 according to the output state of the engine 6. The vaporized gas sent to the engine 6 is supplied as fuel to the intake side of the engine 6 together with the boil-off gas sent through the boil-off gas supply line 8 to operate the engine 6 (step S12).

  As described above, according to the first embodiment, when the LNG flowing in the LNG line 12 is vaporized in the heat exchanger 36, the gas flowing in the gas supply line 30 is cooled by exchanging heat with the LNG. By lowering the temperature of the gas flowing through the gas supply line 30 in this way, energy consumption for supplying the gas to the blowout port 28 provided in the hull of the LNG carrier 1 is reduced.

<Second Embodiment>
FIG. 3 is a schematic diagram showing the internal structure of the LNG carrier 1 including the LNG vaporizer 10 according to the second embodiment of the present invention.

  The present embodiment includes an LNG forced evaporation line 16 provided in parallel with the gas supply line 30 as compared with the first embodiment described above. The LNG forced evaporation line 16 has a configuration similar to that of the reference technique, and on the LNG forced evaporation line 16, a pump 20 which is a circulation device for circulating the heat medium in a closed circuit, and a heat medium A heater 22 for heating is installed.

  In the forced evaporation line 16, the heat medium heated by the heater 22 is circulated by the pump 20. As a result, when the LNG flowing in the LNG line 12 exchanges heat with the heat medium flowing in the forced evaporation line 16, by continuously and stably supplying heat energy from the heat medium flowing in the forced evaporation line 16, Vaporization can be carried out accurately.

  The heat exchanger 36 is configured to be able to switch between the gas flowing through the gas supply line 30 and the heat medium flowing through the LNG forced evaporation line 16 as a medium that exchanges heat with the LNG flowing through the LNG line 12. Such a switching operation is performed, for example, by manually or automatically controlling a flow passage switching valve (not shown). That is, in the present embodiment, when the LNG flowing in the LNG line 12 is vaporized, the LNG forced evaporation line 16 is replaced with the gas flowing in the gas supply line 30 similar to that of the first embodiment, as a heat exchange target with the LNG. It is configured to utilize a flowing heat medium.

  FIG. 4 is a flowchart showing the operation method of the LNG carrier 1 of FIG. 3 for each step.

  Depending on the state of the LNG carrier 1, it is determined whether or not to stop the gas supply to the outlet 28 (step S20). When it is determined that the gas supply to the outlet 28 is stopped (step S20: YES), the gas flow in the gas supply line 30 is stopped by stopping the first blower 34 (step S21). As a result, the gas lubrication system 26 is stopped.

  Then, in the heat exchanger 36, the target of heat exchange with the LNG line 12 is switched from the gas supply line 30 to the LNG forced evaporation line 16 (step S22). Then, by exchanging heat between the heat medium flowing through the LNG forced evaporation line 16 and the LNG flowing through the LNG line 12 in the heat exchanger 36, the LNG is vaporized (step S23).

As described above, in this embodiment, in the case of stopping the supply of gas for the air outlet 28 also, LNG flowing through the LNG line 12 can vaporize by the heat medium and the heat exchange flowing in the forced evaporation line 16. Since the heat medium heated by the heater 22 is circulated by the pump 20 in the forced evaporation line 16, by continuously and stably supplying heat energy from the heat medium flowing in the forced evaporation line 16, the vaporization of LNG is accurately performed. Can be implemented.

  When it is determined that the gas supply to the outlet 28 is not stopped (step S20: NO), the LNG flowing through the LNG line 12 is separated from the gas and the heat flowing through the gas supply line 30 as in the first embodiment. It is vaporized by exchanging it.

<Third Embodiment>
FIG. 5 is a schematic diagram showing an internal structure of an LNG carrier 1 including an LNG vaporizer 10 according to a third embodiment of the present invention.

  In this embodiment, an exhaust line 38 branched from the gas supply line 30 is provided on the downstream side of the heat exchanger 36. The discharge line 38 communicates with a discharge port 40 provided on the low pressure side of the blowout port 28, and is configured so that the connection state can be switched to the gas supply line 30 by a switching valve (not shown). Here, the discharge port 40 is a hole capable of ejecting gas into a space having a lower pressure than the air outlet 28, and may be provided, for example, on the outer surface of the hull above the air outlet 28 or on the deck, or the air outlet. Regardless of the positional relationship with 28, it may be provided in a space (such as a cabin) filled with the atmosphere in the ship. The pressure at the outlet 40 may be lower than the water pressure at the outlet 28, but may be atmospheric pressure, for example.

  When the ejection of gas from the outlet 28 is stopped (regardless of the operating state of the LNG vaporizer 10), the gas in the gas supply line 30 is discharged from the outlet 40 via such an exhaust line 38. Can be discharged. Since the discharge port 40 is provided on the lower pressure side than the blowout port 28, less energy is consumed to blow out the gas than the blowout port 28.

  Further, a parallel line 46, which is provided in parallel with the gas supply line 30, is provided on the upstream side of the branch point 44 of the gas supply line 30 with the discharge line 38. A second blower 48 having a smaller output than the first blower 34 is installed on the parallel line 46. The parallel line 46 is configured to be able to switch the connection state to the gas supply line 30 by a flow path switching valve (not shown).

  When the gas in the gas supply line 30 is discharged from the discharge port 40, the flow path switching valve is controlled so that the parallel line 46 communicates with the gas supply line 30, and the second blower on the parallel line 46 is controlled. 48 may be activated. As a result, the gas can be discharged by the operation of the second blower 48 having a smaller output than that of the first blower 34, so that the energy consumption required for discharge can be further suppressed.

  FIG. 6 is a flowchart showing the operation method of the LNG carrier 1 of FIG. 5 for each step.

  First, depending on the state of the LNG carrier 1, it is determined whether or not the ejection of gas from the outlet 28 is stopped (step S30). When it is determined that the ejection of gas from the outlet 28 is stopped (step S30: YES), the discharge line 38 is communicated with the gas supply line 30 by switching control of a flow passage switching valve (not shown) (step S30: YES). S31).

  After that, the parallel line 46 is made to communicate with the gas supply line 30 by switching control of a flow passage switching valve (not shown) (step S32). Then, the first blower 34 is stopped (step S33), and the second blower 48 on the parallel line 46 is operated (step S34). As a result, the gas in the gas supply line 30 is discharged through the discharge line 38 without being ejected from the air outlet 28. Since the second blower 48 has a smaller output than that of the first blower 34 as described above, the discharge using the second blower 48 consumes less energy.

<Fourth Embodiment>
FIG. 7 is a schematic diagram showing the internal structure of the LNG carrier 1 including the LNG vaporizer 10 according to the fourth embodiment of the present invention.

  In the present embodiment, a bypass line 50 that is provided in parallel with the gas supply line 30 and that bypasses the heat exchanger 36 is provided. The bypass line 50 is configured to connect the upstream side and the downstream side of the heat exchanger 36 of the gas supply line 30, and at least one of both ends thereof is provided with a flow path switching valve for switching the flow path. Has been. The flow path switching valve is configured to be able to bypass the heat exchanger 36 by the gas flowing through the gas supply line 30 by being operated by a control signal from a controller (not shown) or manually.

  FIG. 8 is a flowchart showing the operation method of the LNG carrier 1 of FIG. 7 for each process.

  First, it is determined whether to stop the vaporization of LNG in the LNG vaporizer 10 according to the state of the LNG carrier 1 (step S40). When it is determined that the LNG vaporization in the LNG vaporizer 10 is to be stopped (step S40: YES), the gas flowing through the gas supply line 30 is guided to the bypass line 50 by switching and controlling the flow passage switching valve (not shown). The flow path is switched to (step S41). As a result, the gas flowing through the gas supply line 30 is guided to the air outlet 28 via the bypass line 50 without passing through the heat exchanger 36. As a result, pressure loss that occurs when the gas flowing through the gas supply line 30 passes through the heat exchanger 36 can be avoided, and energy consumption can be reduced. In this way, in the present embodiment, the operation of the gas lubrication system 26 can be continued while suppressing the energy consumption even when the LNG vaporization in the LNG vaporizer 10 is stopped.

<Fifth Embodiment>
FIG. 9 is a schematic diagram showing the internal structure of the LNG carrier 1 including the LNG vaporizer 10 according to the fifth embodiment of the present invention.

  In the present embodiment, the gas supply line 30 branches from the downstream side of the heat exchanger 36 and communicates with at least one of the intake passage of the engine 6 mounted on the LNG carrier 1 or the engine room 52 in which the engine 6 is housed. A cooling gas supply line 54 is provided. Therefore, the gas cooled by exchanging heat with LNG in the heat exchanger 36 is supplied to at least one of the intake passage of the engine 6 or the engine room 52 via the cooling gas supply line 54. As a result, it is possible to reduce the engine power by cooling the intake air of the engine 6 or the cooling power of the engine room 52.

<Sixth Embodiment>
FIG. 10: is a schematic diagram which shows the internal structure of the LNG carrier 1 provided with the LNG vaporizer 10 which concerns on 6th Embodiment of this invention.

  In the present embodiment, the gas supply line 30 is configured to supply the exhaust gas of the engine 6 mounted on the LNG carrier 1 as gas toward the outlet 28. That is, the exhaust passage of the engine 6 is connected to the intake port 32 of the gas supply line 30 via the exhaust supply line 56, so that the exhaust gas of the engine 6 can be supplied to the gas supply line 30. As a result, exhaust gas having a high temperature and pressure is introduced into the heat exchanger 36, so that the heat exchanger 36 can more efficiently vaporize LNG, and the heat exchanger 36 can be downsized. Further, since the exhaust gas having a high pressure is introduced into the gas supply line 30, the energy consumption required for ejecting the gas from the air outlet 28 can be reduced.

  As described above, according to at least one embodiment of the present invention, the LNG vaporization device 10 and the gas lubrication for the LNG carrier 1 capable of reducing the energy consumption for supplying the gas to the air outlet 28 provided in the hull. The system 26 and the operating method of the LNG carrier 1 can be provided.

  The above-described various operations relating to the LNG carrier 1 may be performed manually or automatically by a controller (not shown). In the latter case, the controller is composed of, for example, an electronic arithmetic unit such as a computer, and various kinds of control can be performed by installing a program regarding control contents. Further, such a program may be recorded in a recording medium, and the controller may be configured by reading the recording medium with an electronic arithmetic device.

At least one embodiment of the present invention, the gas lubrication system for blowing out gas from the hull of the ship utilizing LNG, and are available to the operating method of an LNG carrier.

1 LNG Carrier 2 LNG Tank 4 Boil Off Gas 6 Engine 8 Boil Off Gas Supply Line 10 LNG Vaporizer 12 LNG Line 14 Vaporized Gas Supply Line 16 Forced Evaporation Line 18, 36 Heat Exchanger 20 Pump 22 Heater 24 Compressor 26 Gas Lubrication System 28 Blowing Outlet 30 Gas supply line 32 Inlet 34 First blower 38 Discharge line 40 Discharge port 44 Branch point 46 Parallel line 48 Second blower 50 Bypass line 52 Engine room 54 Cooling gas supply line 56 Exhaust supply line

Claims (15)

A gas lubrication system for a ship to use the L NG,
The LNG flowing through the LNG line connected to the LNG tank of the LNG carrier , which is provided on the gas supply line for supplying gas to the outlet provided in the hull of the ship, and the gas supply line. A gas supply line extending through the interior of the heat exchanger of an LNG vaporizer for vaporizing LNG to the outlet, comprising a heat exchanger configured to exchange heat with the gas;
A first blower provided on the gas supply line between the heat exchanger and the outlet.
A gas lubrication system for a ship using LNG including. An LNG forced evaporation line provided in parallel with the gas supply line,
The heat exchanger is
The LNG according to claim 1, wherein the medium that exchanges heat with the LNG flowing through the LNG line is switchable between the gas flowing through the gas supply line and the heat medium flowing through the LNG forced evaporation line. A gas lubrication system for ships. A circulation device provided in the LNG forced evaporation line for circulating the heat medium;
A heater provided in the LNG forced evaporation line for heating the heat medium,
A gas lubrication system for a ship utilizing the LNG according to claim 2, comprising: Branched from the gas supply line also on the downstream side of the heat exchanger, and comprises a discharge line communicating with the discharge port provided in the low pressure side of the air outlet, any one of claims 1 to 3 A gas lubrication system for a ship using the LNG according to claim 1. Of the gas supply line, on the upstream side from the branch point with the discharge line, a parallel line provided in parallel with the gas supply line,
A second blower installed on the parallel line and having a smaller output than the first blower,
A gas lubrication system for a ship utilizing the LNG according to claim 4 , comprising: The gas lubrication system for a ship utilizing LNG according to any one of claims 1 to 5 , further comprising a bypass line that is provided in parallel with the gas supply line and that bypasses the heat exchanger. A cooling gas supply line that branches from a downstream side of the heat exchanger among the gas supply lines and communicates with at least one of an intake passage of an engine mounted on the ship or an engine room in which the engine is housed, A gas lubrication system for a ship, which utilizes the LNG according to any one of items 1 to 6 . The LNG according to any one of claims 1 to 7 , wherein the gas supply line is configured to supply exhaust gas of an engine mounted on the ship as the gas toward the outlet. Gas lubrication system for ships. Flowing a gas through a gas supply line toward an outlet provided in the hull of a ship that uses LNG;
By heat exchange with the gas flowing through the gas supply line, a step of vaporizing the LNG flowing through the LNG line connected to the LNG tank L NG carrier,
At least using the vaporized gas obtained by the vaporization of the LNG as a fuel, operating the engine of the vessel,
A method for operating a ship, which uses an LNG including: A step of vaporizing the LNG by exchanging heat between the heat medium flowing through the LNG forced evaporation line provided in parallel with the gas supply line and the LNG when the supply of the gas to the outlet is stopped. A method for operating a ship utilizing the LNG according to claim 9 , comprising: When the ejection of the gas from the outlet is stopped, the gas that has undergone heat exchange with the LNG is discharged through a discharge line branched from the gas supply line to a discharge provided on a lower pressure side than the discharge outlet. The method for operating a ship utilizing LNG according to claim 9 or 10 , comprising the step of discharging the water to an outlet. The LNG and the heat exchanged the gas, said comprising the step of providing at least one of an engine room in which the intake passage or the engine of an engine mounted on the LNG carrier is accommodated, either one of claims 9 11 single A method of operating a ship, which uses the LNG according to the item. The method for operating a ship utilizing LNG according to any one of claims 9 to 12 , comprising a step of causing exhaust gas of an engine of the LNG carrier to flow into the gas supply line as the gas. The first blower provided in the gas supply line on the downstream side of the heat exchanger that performs heat exchange between the LNG and the gas ejects the gas heat-exchanged with the LNG from the outlet. The method for operating a ship utilizing LNG according to any one of claims 9 to 13 , comprising a step. When operating the engine using only boil-off gas from the LNG tank as fuel, the method includes a step of bypassing a heat exchanger that performs heat exchange between the LNG and the gas and supplying the gas to the air outlet. A ship operating method utilizing the LNG according to any one of claims 9 to 14 .

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