WO2016031211A1

WO2016031211A1 - Ship

Info

Publication number: WO2016031211A1
Application number: PCT/JP2015/004201
Authority: WO
Inventors: 健治長町; 岳夫宇井; 信彦杉山; 崇嗣安部
Original assignee: 川崎重工業株式会社
Priority date: 2014-08-29
Filing date: 2015-08-21
Publication date: 2016-03-03
Also published as: CN106458310B; JP2016049881A; CN106458310A; KR20170015512A

Abstract

This ship is provided with: a tank that retains liquefied gas; a plurality of diesel engines that each drive a main shaft provided with a propeller; a booster that boosts the liquefied gas or evaporating gas supplied from the tank; and a supply line that extends from the booster to the plurality of diesel engines. The booster boosts the liquefied gas or evaporating gas supplied from the tank so that the evaporating gas to be supplied to the diesel engines becomes higher than the highest required pressure of the required pressures of the plurality of diesel engines. The supply line includes a main flow path connected to the booster, and a plurality of branch paths. Each of the plurality of branch paths is provided with a pressure-regulating valve.

Description

Ship

The present invention relates to a ship equipped with a plurality of diesel engines that use gas as fuel.

In recent years, from the viewpoint of environmental impact, ships using a gas-fired diesel engine that uses natural gas as a fuel for propulsion have attracted attention. As a ship equipped with a gas-fired diesel engine, a multi-machine / multi-shaft ship is known which is equipped with a plurality of main engines and drives a main shaft provided with a propeller in each main engine.

For example, Patent Document 1 discloses a two-machine two-shaft ship equipped with a low-speed dual-fuel diesel (DFD) engine as a gas-fired diesel engine and a propeller driven by the low-speed DFD engine. . This ship has a LNG tank for storing LNG, an LNG pump disposed in the LNG tank, LNG supplied from the LNG tank via the LNG pump to high pressure gas, and the LNG converted to high pressure gas is converted to a low speed DFD engine. A high-pressure fuel gas supply system is provided. Although not specifically described in Patent Document 1, it is presumed that the high-pressure gas supply system includes a high-pressure pump (pressure increase device) and a vaporizer.

JP2013-193503A

By the way, in a multi-machine / multi-shaft vessel equipped with a gas-fired diesel engine, the output required for each engine may differ. For example, there are individual differences at the time of manufacture in engines and propellers, and there is a difference in output required when driving at the same rotational speed. In addition, the rotational speeds of a plurality of propellers may be intentionally changed in order to move the hull straight in a crosswind or wave. In such a case, it is desirable to supply fuel gas having a pressure corresponding to the output required for each engine. However, in the ship disclosed in Patent Document 1, fuel gas is supplied to two engines from one high-pressure gas supply system, and fuel gases having different pressures cannot be supplied to the engines. In order to supply fuel gas at different pressures, it is conceivable to provide a high-pressure gas supply system for each engine.However, since there is a limited installation space on the ship, a high-pressure pump, a carburetor, etc. It is not preferable to provide a high-pressure gas supply system including each engine.

Therefore, an object of the present invention is to provide a ship that can supply fuel gas of different pressures to two or more gas-fired diesel engines and can save space.

In order to solve the above problems, a ship according to the present invention includes a tank for storing liquefied gas, and a plurality of diesel engines that drive a main shaft provided with a propeller that uses evaporated gas vaporized from the liquefied gas as fuel. And a booster that boosts the liquefied gas or evaporated gas supplied from the tank so that the evaporated gas supplied to the diesel engine is higher than the highest required pressure among the required pressures of the plurality of diesel engines, A supply line extending from the booster to the plurality of diesel engines, the supply line including a main flow path connected to the booster and a plurality of branch paths connected to the plurality of diesel engines, and the plurality of branches And a pressure regulating valve provided in each of the paths.

According to the above configuration, since the pressure regulating valve is provided in each of the branch passages connected to the diesel engine, the opening degree of the pressure regulating valve is adjusted, and the gas pressure supplied to the engine is required for each diesel engine. The pressure can be adjusted according to the output. In addition, fuel gas of different pressures can be supplied to a plurality of diesel engines with a single booster, so that a high pressure gas supply system is provided for each engine in order to supply fuel gas of different pressures to each engine. It is possible to save space on the ship.

In the above configuration, the boosting device may be a pump that boosts the liquefied gas, and a vaporizer that vaporizes the liquefied gas discharged from the pump may be provided in the main flow path.

In the above configuration, the control device that controls the pressure regulating valve according to the pressure required by each of the plurality of diesel engines, and a branch from the portion between the pump and the carburetor in the main flow path. A recirculation line connected to the tank, and a flow rate control valve provided in the recirculation line, wherein the control device is configured to control the pump and the flow rate according to the pressure required by each of the plurality of diesel engines. The control valve may be controlled. According to this configuration, the control device can control the pump and the flow rate control valve to adjust the pressure of the evaporated gas vaporized by the vaporizer, that is, the pressure on the primary side of the branching pressure regulating valve. . For this reason, the primary pressure of the pressure regulating valve can be appropriately changed in accordance with the required pressure of the engine so that the differential pressure at the pressure regulating valve is within a predetermined range.

The ship may further include a bypass passage that communicates a primary side and a secondary side of the pressure adjustment valve, and a pressure adjustment valve or an on-off valve provided in the bypass passage. According to this configuration, when a pressure regulating valve is provided in the bypass flow path in parallel with the pressure regulating valve in the branch path, if the adjustable flow rate of these pressure regulating valves is different, the gas flow rate to the engine or the demand from the engine It is possible to appropriately adjust the supply gas pressure to the engine by changing the pressure regulating valve to be used according to the pressure. Further, when an on-off valve is provided in the bypass flow path, the upstream side and the downstream side of the branch pressure adjusting valve can be made the same pressure by opening the on-off valve.

The ship includes a plurality of buffer tanks communicating with the plurality of branch passages on the downstream side of the pressure regulating valve, a downstream portion of the pressure regulating valve in each of the plurality of branch passages, and the plurality of buffer tanks. And a bleed line connected to each of the plurality of buffer tanks, and a bleed valve provided on the bleed line.

When one of the diesel engines stops due to an engine trouble, the gas is supplied to the engine more than the gas consumption of the engine in the entire ship, and the gas pressure in the supply line increases. On the other hand, according to the above configuration, the buffer tank can be set to a low pressure by closing the opening / closing valve at the inlet of the buffer tank and opening the bleed valve provided in the bleed line. That is, when a gas pressure increase occurs in the supply line due to an engine trouble or the like, a sudden increase in pressure in the supply line can be prevented by opening the on-off valve and communicating the buffer tank that has been kept at a low pressure with the supply line. .

The ship includes a pressure regulating valve in a second branch path different from the first branch path of the plurality of branch paths and a downstream portion of the pressure regulation valve in the first branch path of the plurality of branch paths. A cross feed line communicating with the downstream portion of the cross feed line and a cross feed valve provided in the cross feed line may be further provided. According to this configuration, even when a pressure regulating valve in one of the branch paths fails and gas pressure adjustment on the downstream side becomes impossible, the cross feed line is connected to the engine on the downstream side of the failed pressure regulating valve. The gas can be supplied via Further, when the cross feed valve is a pressure regulating valve or a flow rate control valve, the gas pressure supplied to the engine on the downstream side of the failed pressure regulating valve can be adjusted.

In the above ship, the pressure adjustment in the second branch path different from the first branch path of the plurality of branch paths and the downstream portion of the pressure regulating valve in the first branch path of the plurality of branch paths. A cross feed line communicating with a downstream portion of the valve; a buffer tank provided in the cross feed line; and a first portion provided in the cross feed line between the buffer tank and the first branch passage. You may further provide 1 on-off valve and the 2nd on-off valve provided in the part between the said buffer tank and the said 2nd branch path in the said cross feed line. According to this configuration, since a common buffer tank is provided for the plurality of branch paths, it is not necessary to provide a buffer tank for each engine. For this reason, space saving in a ship can be achieved.

The ship may further include a bleed line connected to the buffer tank of the cross feed line and a bleed valve provided in the bleed line. When one of a plurality of diesel engines stops due to an engine trouble, the gas is supplied to the engine more than the gas consumption of the engine in the entire ship, and the gas pressure in the supply line increases. On the other hand, according to the above configuration, the buffer tank can be set to a low pressure by closing the opening / closing valve at the inlet of the buffer tank and opening the bleed valve provided in the bleed line. That is, when a gas pressure rises due to an engine trouble or the like, a sudden increase in pressure in the supply line can be prevented by opening the open / close valve to communicate with the buffer tank that has been kept at a low pressure.

The diesel engine can be switched between oil operation that uses only oil as fuel and gas operation that uses only oil or both oil and gas as fuel. In this case, a dual fuel diesel engine that diffuses and burns gas may be used. According to this configuration, it is possible to quickly switch from oil operation to gas operation.

The diesel engine can be switched between oil operation that uses only oil as fuel and gas operation that uses only oil or both oil and gas as fuel. In this case, a dual fuel diesel engine that premixes and burns gas may be used. According to this configuration, it is possible to quickly switch from oil operation to gas operation.

Further, when the diesel engine is operated with gas fuel, the required pressure may change according to the output of the diesel engine.

According to the present invention, it is possible to provide a ship capable of supplying fuel gas having different pressures to two or more gas-fired diesel engines and saving space.

It is a schematic structure figure showing some ships concerning a 1st embodiment of the present invention. It is a schematic block diagram which shows a part of ship which concerns on 2nd Embodiment of this invention. It is a schematic block diagram which shows a part of ship which concerns on 3rd Embodiment of this invention. It is a schematic block diagram which shows a part of ship which concerns on 4th Embodiment of this invention. It is a schematic block diagram which shows a part of ship which concerns on 5th Embodiment of this invention. It is a schematic block diagram which shows a part of ship which concerns on 6th Embodiment of this invention. It is a figure which shows the modification of the gas supply system in the ship of FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. Below, the same code | symbol is attached | subjected to the element which is the same or it corresponds through all the drawings, and the overlapping description is abbreviate | omitted.

<First Embodiment>
FIG. 1 shows a part of a ship 1A according to the first embodiment of the present invention. The marine vessel 1A includes a first diesel engine 51a (hereinafter simply referred to as “first engine 51a”) and a second diesel engine 51b (hereinafter simply referred to as “second engine 51b”) as propulsion main engines. It is a two-machine two-axis type ship equipped. The first engine 51a drives the main shaft 52a provided with the propeller 53a, and the second engine 51b drives the main shaft 52b provided with the propeller 53b.

The first engine 51a and the second engine 51b are both DFD engines that can use both oil and gas as fuel. This ship 1A has an oil supply system (not shown) for supplying oil to the

engines

51a and 51b through the

oil supply lines

54a and 54b, and a gas supply system 10A for supplying gas to the engines 51a and 51b. is doing.

The gas supply system 10A supplies the evaporated gas obtained by vaporizing the liquefied gas to the

engines

51a and 51b as fuel. The gas supply system 10A extends from the tank 2 that stores liquefied gas, the high-pressure pump (an example of the booster of the present invention) 41 that boosts the liquefied gas supplied from the tank 2, and the high-pressure pump 41 to the

engines

51a and 51b. A gas supply line 3 is included. The gas supply line 3 is provided with a vaporizer 42 that vaporizes the liquefied gas discharged from the high-pressure pump 41.

Tank 2 is at least one of large transport tanks arranged in the direction of the length of ship 1A. However, when a suction drum is disposed between the transport tank and a high-pressure pump 41 described later, the tank 2 may be the suction drum. The liquefied gas stored in the tank 2 in this embodiment is LNG, and the tank 2 has a heat insulation performance capable of maintaining a cryogenic state so that the LNG can be maintained in a liquid state of about −162 ° C. under atmospheric pressure. Have. Note that the liquefied gas is not necessarily LNG, and may be LPG or liquid hydrogen, for example.

The high pressure pump 41 is controlled by the control device 45 so that the evaporated gas vaporized by the vaporizer 42 supplied to the first engine 51a and the second engine 51b becomes higher than the required pressure (for example, 15 to 30 MPa). The pressure of the liquefied gas supplied from the tank 2 is increased. Here, "the evaporated gas vaporized by the vaporizer 42 supplied to the first engine 51a and the second engine 51b becomes higher than the required pressure" means that the first engine 51a and the second engine 51b This means that the required pressure is higher than the highest required pressure. The high-pressure pump 41 is, for example, a piston pump, and includes a plurality of pistons that are driven by a hydraulic motor to push out liquefied gas from the cylinder. Further, the high-pressure pump 41 is configured to be able to change the rotation speed (for example, the rotation speed of the hydraulic motor), and can change the pump discharge amount substantially in proportion to the rotation speed of the high-pressure pump 41.

The vaporizer 42 is, for example, a heat exchanger in which meandering tubes are arranged in a shell. The shell is connected to a circulation line (not shown), and a heat medium such as glycol is circulated through the shell and the circulation line.

The gas supply line 3 includes a main channel 31 connected to the high-pressure pump 41 and two branch channels (first branch channel 32 and second branch channel 33) communicating with the main channel 31. The first branch path 32 is connected to the first engine 51a, and the second branch path 33 is connected to the second engine 51b. The vaporizer 42 is provided in the main flow path 31 in the gas supply line 3.

The gas supply system 10A includes a reflux line 44 that branches from a portion between the high pressure pump 41 and the vaporizer 42 in the main flow path 31 of the gas supply line 3 and connects to the tank 2, and a flow rate control provided in the reflux line 44. And a valve 43. A part of the liquefied gas boosted by the high-pressure pump 41 can be returned to the tank 2 through the reflux line 44, and the opening of the flow rate control valve 43 is changed by the control device 45. The flow rate of the liquefied gas passing therethrough can be adjusted. In this embodiment, by adjusting the rotation speed of the high-pressure pump 41 and the opening degree of the flow control valve 43, the pressure of the evaporated gas vaporized by the vaporizer 42 on the downstream side of the high-pressure pump 41 can be adjusted. . The pressure of the evaporated gas vaporized by the carburetor 42 is a pressure higher than the higher required pressure of the first engine 51a and the second engine 51b by the pressure loss at the pressure regulating valve. is there. Further, the pressures of the evaporated gas vaporized by the vaporizer 42 are the first engine 51a and the second engine 51b so that it is not necessary to change the pressure of the evaporated gas vaporized by the vaporizer 42 according to the change in the required pressure. The pressure may be adjusted to be higher by the pressure loss than the maximum operational pressure.

The first branch path 32 is provided with a first pressure regulating valve 61a, and the second branch path 33 is provided with a second pressure regulating valve 61b. By controlling the opening degree of the first pressure regulating valve 61a, the pressure of the downstream portion 322 of the first pressure regulating valve 61a in the first branch path 32 can be changed. Moreover, the pressure of the downstream part 332 of the 2nd pressure regulation valve 61b in the 2nd branch path 33 can be changed by controlling the opening degree of the 2nd pressure regulation valve 61b.

The buffer tank 71a communicates with the downstream portion 322 of the first pressure regulating valve 61a in the first branch path 32, and the downstream side of the second pressure regulating valve 61b in the second branch path 33. A buffer tank 71b communicates with the portion 332. The

buffer tanks

71a and 71b can prevent sudden pressure fluctuations in the gas supply line 3.

Further, a first switching valve 63a, which is an on-off valve, is provided on the downstream side of the branch point to the buffer tank 71a in the first branch path 32, and to the buffer tank 71b in the second branch path 33. A second switching valve 63b, which is an on-off valve, is provided downstream of the branch point. The first switching valve 63a is opened immediately before the gas operation of the first engine 51a, and the second switching valve 63b is opened immediately before the gas operation of the second engine 51b. In addition, an accumulator 64a is provided between the first switching valve 63a and the first engine 51a in the first branch path 32, and the second switching valve 63b and the second switching valve 63b in the second branch path 33 are provided. An accumulator 64b is provided between the second engine 51b.

Each of the first engine 51a and the second engine 51b is an electronically controlled gas injection (ME-GI) DFD engine, which uses only oil as fuel by electronic control and only gas or oil. And gas operation using gas as fuel can be switched. The first engine 51a and the second engine 51b each diffusively burn oil in the case of oil operation, and diffusively burn gas in the case of gas operation.

The first engine 51a and the second engine 51b are connected to an engine control unit (not shown) that controls gas injection pressure in the engine and switching between gas operation and oil operation. The engine control unit requests the control device 45 of the gas supply system 10 </ b> A for evaporating gas having a pressure (hereinafter referred to as “required pressure”) corresponding to each engine output. In the gas supply system 10A, the opening degrees of the

pressure adjustment valves

61a and 61b are adjusted so that the gas pressures (required pressures) required as the supply gas pressures to the first engine 51a and the second engine 51b are adjusted. Adjusted. In FIG. 1 and subsequent drawings, in order to simplify the drawings, control lines between the respective components controlled by the control device 45 and the control device 45 are omitted.

For example, when the required pressure of the first engine 51a is 28 MPa and the required pressure of the second engine 51b is 24 MPa, the evaporated gas vaporized by the vaporizer 42 is the higher of these required pressures. The pressure of the liquefied gas is increased by the high-pressure pump 41 so that the pressure is higher than the required pressure, for example, 29 MPa. Then, the opening degree of the first pressure adjustment valve 61a is adjusted by the control device 45 so that the gas pressure in the downstream portion 322 of the first branch path 32 from the first pressure adjustment valve 61a becomes 28 MPa. The opening degree of the second pressure regulating valve 61b is adjusted so that the gas pressure in the downstream portion 332 of the second branch path 33 from the second pressure regulating valve 61b is 24 MPa.

As described above, in the marine vessel 1A according to the present embodiment, the high-pressure pump 41 boosts the evaporated gas supplied to the first engine 51a and the second engine 51b so as to be higher than the required pressure in the engine.

Pressure regulating valves

61a and 61b are provided in the

branch paths

32 and 33 connected to the first engine 51a and the second engine 51b, respectively. For this reason, even when the first engine 51a and the second engine 51b request the gas supply system 10A for fuel gas having different pressures, the opening degree of the

pressure regulating valves

61a and 61b is adjusted respectively. The gas pressure supplied to the engine can be a pressure corresponding to the output required for each engine. In addition, since the gas supply system 10A can supply the fuel gas having different pressures to the two

engines

51a and 51b, the gas supply system is provided for each engine and the engine is supplied to the engine rather than the ship that supplies the fuel gas having different pressures. Space saving of the gas supply system can be achieved.

By the way, in the configuration of the ship disclosed in Patent Document 1, gas operation may be started one by one for a plurality of engines. For example, if gas operation of another engine is started during gas operation of a certain engine, that is, gas consumption is started, the gas supply amount to the engine during gas operation also fluctuates immediately thereafter. For this reason, it is desirable to keep supplying gas stably to the engine which is continuing gas operation, receiving the change of the gas consumption at the time of gas operation start. Moreover, even when a certain engine suddenly stops the gas operation due to a trouble or the like among a plurality of engines during the gas operation, it is desirable that the gas supply to other engines can be continued stably.

In the ship 1A of the present embodiment, when the first engine 51a is in gas operation and the gas operation of the second engine 51b is started, it is more than the second pressure regulating valve 61b in the second branch path 33. The second switching valve 63b can be opened after the gas pressure in the upstream side of the second switching valve 63b and the buffer tank 71b is increased to the set pressure on the downstream side. The gas upstream of the buffer tank 71b and the second switching valve 63b flows into the accumulator 64b on the downstream side of the second switching valve 63b, and is more than the second pressure regulating valve 61b in the second branch path 33. The gas pressure in the downstream portion 332 will decrease. However, since the gas boosted to the set pressure is held in the buffer tank 71b, it is possible to prevent a sudden pressure drop when the second switching valve 63b is opened.

Further, in the ship 1A of the present embodiment, when the first engine 51a is in gas operation and the second engine 51b starts or stops gas operation, the second pressure regulating valve 61b Since the change in the flow rate of the gas flowing into the second branch passage 33 can be moderated, the gas can be stably supplied to the first engine 51a during the gas operation.

That is, the gas pressure in the downstream portion 322 of the first branch path 32 from the first pressure regulating valve 61a suddenly decreases and does not deviate from the allowable range, and the second branch path 33 has the second pressure. The rotational speed of the high-pressure pump 41, the opening degree of the flow control valve 43, the first pressure so that the gas pressure in the downstream portion 332 of the second pressure adjustment valve 61b is adjusted to the required pressure of the second engine 51b. The pressure regulating valve 61a and the second pressure regulating valve 61b can be controlled. Thereby, the supply gas pressure to the 2nd engine 51b can be raised, suppressing the fluctuation | variation of the supply gas pressure to the 1st engine 51a during a gas driving | operation within the tolerance | permissible_range. Therefore, the gas operation of the second engine 51b can be started while stably supplying the gas to the first engine 51a during the gas operation.

Second Embodiment
Next, with reference to FIG. 2, the ship 1B which concerns on 2nd Embodiment of this invention is demonstrated. In addition to the components of the first embodiment, the gas supply system 10B according to the second embodiment includes a bypass channel that communicates the primary side and the secondary side of the first pressure regulating valve 61a of the first branch path 32. 34 a and a bypass flow path 34 b that communicates the primary side and the secondary side of the second pressure regulating valve 61 b of the second branch path 33. Further, in the gas supply system 10B according to the second embodiment, the bypass flow path 34a is provided with a third pressure adjustment valve 62a having a flow rate adjustable from the first pressure adjustment valve 61a. The path 34b is provided with a fourth pressure regulating valve 62b having an adjustable flow rate different from that of the second pressure regulating valve 61b.

Also in this embodiment, the same effect as in the first embodiment can be obtained. In the present embodiment, a third pressure regulating valve 62a having a different adjustable flow rate from the first pressure regulating valve 61a is provided in the bypass flow path 34a, and the second pressure regulating valve 61b has an adjustable flow rate. A fourth pressure regulating valve 62b having a different angle is provided in the bypass flow path 34b. For this reason, it is possible to adjust the gas pressure by appropriately selecting a pressure adjustment valve used for pressure adjustment according to the required pressure of the engine. For example, when the first engine 51a is set to a low output and the gas flow rate to the first engine 51a falls outside the adjustable flow rate range of the first pressure regulating valve 61a, the first pressure regulating valve 61a is used instead. In addition, the gas pressure can be adjusted using the third pressure regulating valve 62a of the bypass channel 34a within the range of the adjustable flow rate. Thereby, the gas pressure supplied to the engine can be adjusted appropriately. For example, even when the gas consumption in the engine is small, the pressure can be adjusted stably.

In this embodiment, the valves provided in the

bypass channels

34a and 34b may be on-off valves. When the on-off valves are provided in the

bypass passages

34a, 34b, the

pressure adjustment valves

61a, 61b of the

branch paths

32, 33 are not adjusted by opening the on-off valves, and the

branch paths

32, 33 Pressure loss between the

upstream side

321 and 331 and the

downstream side

322 and 332 can be minimized.

<Third Embodiment>
Next, with reference to FIG. 3, a ship 1C according to a third embodiment of the present invention will be described. In addition to the components of the first embodiment, the ship 1 </ b> C according to the third embodiment includes a downstream portion 322 of the first pressure regulating valve 61 a in the first branch path 32 and a second in the second branch path 33. A cross feed line 82 communicating with the downstream portion 332 of the pressure regulating valve 61b, and a cross feed valve 81 provided in the cross feed line 82.

The cross feed valve 81 may be a flow control valve that enables gas flow in both directions of the cross feed line 82. When the cross feed valve 81 is a flow rate control valve, the gas flow rate is adjusted by the cross feed valve 81 so that the downstream portion 322 of the first pressure regulating valve 61a in the first branch path 32 and the second branch path. It is possible to adjust the downstream portion 332 of the second pressure regulating valve 61b at 33. Further, the cross feed valve 81 may be a pressure regulating valve. Further, there may be a plurality of cross feed valves 81 and cross feed lines 82.

Also in this embodiment, the same effect as in the first embodiment can be obtained. In addition, even if the pressure adjustment valve in one of the branch passages fails and gas pressure adjustment on the downstream side becomes impossible, gas is supplied to the engine on the downstream side of the failed pressure adjustment valve via the cross feed line. The pressure can be adjusted by a cross feed valve. For example, even when the second pressure regulating valve 61b of the second branch passage 33 fails and the gas pressure cannot be adjusted in the downstream portion 332 thereof, the second pressure regulating valve 61b on the downstream side of the failed second pressure regulating valve 61b. The second engine 51 b can be supplied with gas via the cross feed line 82, and the gas pressure can be adjusted by the cross feed valve 81 of the cross feed line 82.

<Fourth embodiment>
Next, with reference to FIG. 4, a ship 1D according to a fourth embodiment of the present invention will be described. In addition to the components of the first embodiment, the marine vessel 1D according to the fourth embodiment includes a downstream portion 322 of the first pressure regulating valve 61a in the first branch path 32 and a second in the second branch path 33. The cross feed line 94 is provided to communicate with the downstream portion 332 of the pressure regulating valve 61b. Further, the ship 1D according to the fourth embodiment has a cross feed line 94 instead of the buffer tank 71a communicated with the first branch path 32 and the buffer tank 71b communicated with the second branch path 33 of the first embodiment. A buffer tank 91 is provided. A first opening / closing valve 92 is provided in a portion 94 a between the buffer tank 91 and the first branch path 32 in the cross feed line 94, and the buffer tank 91 and the second branch path 33 in the cross feed line 94 are provided. A second opening / closing valve 93 is provided in the portion 94b between the two.

Also in this embodiment, the same effect as in the first embodiment can be obtained. Further, for example, when the second engine 51b is stopped due to an engine trouble, the second on-off valve 93 is opened to allow the buffer tank 91 and the gas supply line 3 to communicate with each other, so that the second branch path in the gas supply line 3 A rapid pressure increase of 33 can be prevented. Furthermore, in this embodiment, since it is not necessary to provide a buffer tank for each engine, space saving in the ship can be achieved.

<Fifth Embodiment>
Next, with reference to FIG. 5, the ship 1E which concerns on 5th Embodiment of this invention is demonstrated. In addition to the components of the first embodiment, the ship 1E according to the fifth embodiment includes a communication portion 72a between the downstream portion 322 of the first pressure regulating valve 61a and the buffer tank 71a in the first branch path 32. The on-off valve 73a provided, and the on-off valve 73b provided in the communication portion 72b between the downstream portion 332 of the second pressure regulating valve 61b and the buffer tank 71b in the second branch path 33 are provided. Further, the ship 1E according to the fifth embodiment has

bleed lines

75a and 75b connected to the

buffer tanks

71a and 71b, respectively, and bleeds provided on the

bleed lines

75a and 75b, respectively, so as to allow the evaporated gas in the buffer tank to escape.

Valves

74a and 74b are further provided.

The

bleed valves

74a and 74b are, for example, pressure regulating valves and flow control valves. For example, the downstream ends of the

bleed lines

75a and 75b may be connected to the tank 2 so that a part of the evaporated gas in the buffer tank is returned to the tank 2 through the

bleed lines

75a and 75b. Alternatively, at the downstream end of the

bleed lines

75a and 75b, for example, a part of the evaporated gas in the buffer tank is supplied as fuel for a power generation engine, a boiler (not shown) or the like through the

bleed lines

75a and 75b. It may be connected to a power generation engine, a boiler, or the like. Alternatively, the downstream ends of the

bleed lines

75a and 75b may be connected to an incineration processing system (not shown) so that, for example, a part of the evaporated gas in the buffer tank is incinerated.

Also in this embodiment, the same effect as in the first embodiment can be obtained.

By the way, when one of the first engine 51a and the second engine 51b stops due to an engine trouble, the gas consumption of the engine in the entire ship is approximately halved, and the gas pressure in the gas supply line 3 is temporarily reduced. Will rise. However, in this embodiment, the

buffer tanks

71a and 71b can be kept at a low pressure by closing the on-off

valves

73a and 73b in advance and opening the

bleed valves

74a and 74b provided on the

bleed lines

75a and 75b. That is, when a gas pressure rises in the gas supply line 3 due to an engine trouble or the like, the gas supply line 3 is made to communicate with the

buffer tanks

71a and 71b that are kept at a low pressure by opening the on-off

valves

73a and 73b. A sudden pressure increase in the line 3 can be prevented.

Further, by opening the on-off

valves

73a and 73b and closing the

bleed valves

74a and 74b provided on the

bleed lines

75a and 75b, the pressure in the

buffer tanks

71a and 71b can be made equal to the supply gas pressure to the engine. it can. Thereby, a pressure fluctuation can be reduced with respect to a sudden load increase of the engine.

Further, when none of the engines is in gas operation, for example, when any engine is in oil operation or when the ship 1E is anchored, the on-off

valves

73a and 73b are opened, and the bleed valves 74a provided on the

bleed lines

75a and 75b. , 74b can be used to decompress the entire gas supply line 3.

<Sixth Embodiment>
Next, with reference to FIG. 6, the ship 1F which concerns on 6th Embodiment of this invention is demonstrated. A ship 1F according to the sixth embodiment is provided in a bleed line 96 and a bleed line 96 connected to the buffer tank 91 so as to release the evaporated gas in the buffer tank 91 in addition to the components of the fourth embodiment. A bleed valve 95 is further provided.

In this embodiment, the same effect as that of the fourth embodiment can be obtained. Also in this embodiment, the first on-off valve 92 and the second on-off valve 93 are closed and the bleed valve 95 provided on the bleed line 96 is opened, so that the buffer tank 91 can be kept at a low pressure. Effects similar to those of the fifth embodiment can be obtained. Further, when none of the engines is in gas operation, the first on-off valve 92 and the second on-off valve 93 are opened, and the bleed valve 95 provided on the bleed line 96 is opened, whereby the entire gas supply line 3 is decompressed. be able to. Furthermore, in this embodiment, since it is not necessary to provide a buffer tank for each engine, space saving in the ship can be achieved.

<Switching between oil operation and gas operation>
In the first to sixth embodiments, when switching between oil operation and gas operation one by one for a plurality of DFD engines, when one engine is in gas operation, the gas pressure supplied to another engine is reduced. This is particularly advantageous because it can be set to a constant pressure or maintained at a set pressure. In addition, when the gas operation of one engine is continued while the gas operation of another engine is started, the gas flow rate changes rapidly. The gas fuel can be stably supplied. Hereinafter, as an example, a method of switching between oil operation and gas operation for the ship 1F according to the sixth embodiment will be described.

Consider the case where the first engine 51a is in gas operation and the second engine 51b is in oil operation in the ship 1F according to the sixth embodiment. The first engine 51a has an engine output of 80% and a required pressure of 28 MPa. The pressure of the evaporated gas vaporized by the vaporizer 42 is 29 MPa. By adjusting the first pressure regulating valve 61 a of the first branch path 32, the supply gas pressure to the first engine 51 a is kept at 28 MPa. I'm leaning. On the other hand, since the second engine 51b is in oil operation, the second pressure regulating valve 61b of the second branch path 33 is fully closed, the first on-off valve 92 and the second on-off valve 93 are closed, and the bleed With the valve 95 opened, the gas pressure and the buffer tank 91 in the downstream portion 332 of the second branch path 33 from the second pressure regulating valve 61b are kept at a low pressure.

While the second engine 51b is in the oil operation, keeping the standby state in which the gas pressure supplied to the second engine 51b is maintained at a constant high pressure (for example, a set pressure of 24 MPa) is the second engine 51b. This is preferable because the switching time from oil operation to gas operation can be shortened. In order to put the second engine 51b in the oil operation into the standby state, the bleed valve 95 is closed, the second on-off valve 93 is opened, and the supply gas pressure to the first engine 51a during the gas operation is suddenly increased. The second pressure regulating valve 61b of the second branch path 33 is slightly opened so as not to fluctuate. In this way, the gas pressure in the downstream portion 332 of the second branch path 33 relative to the second pressure regulating valve 61b is increased, and the second pressure regulating valve 61b is fully closed when, for example, the set pressure approaches 24 MPa. As a result, the second engine 51b in the oil operation can be set to the standby state of the gas operation, and the switching time from the oil operation to the gas operation in the second engine 51b can be shortened.

Even when the second pressure regulating valve 61b is fully closed, a small amount of gas leaks to the secondary side of the second pressure regulating valve 61b, and the supply gas pressure to the second engine 51b gradually increases. Can adjust the opening degree of the bleed valve 95 to maintain the supply gas pressure to the second engine 51b at a set pressure in a standby state (for example, a set pressure of 24 MPa).

When the second engine 51b in the gas operation standby state (and in the oil operation) is switched to the gas operation, the second switching valve 63b is opened, so that the upstream side of the buffer tank 91 and the second switching valve 63b. Side gas flows into the accumulator 64b on the downstream side of the second switching valve 63b. As a result, the gas pressure in the downstream portion 332 of the second branch path 33 from the second pressure regulating valve 61b is lowered, but the gas raised to the set pressure was held in the buffer tank 91. Thus, it is possible to prevent a sudden pressure drop when the second switching valve 63b is opened.

On the other hand, the gas pressure in the downstream portion 322 of the first branch path 32 relative to the first pressure regulating valve 61a suddenly decreases and does not deviate from the allowable range, and the required pressure of the second engine 51b. The rotation speed of the high-pressure pump 41, the opening degree of the flow control valve 43, the first pressure adjustment valve 61a, and the second pressure adjustment valve 61b are controlled so as to be adjusted to (for example, 25 MPa). Thereby, the second engine 51b can be switched from the oil operation to the gas operation. In addition, the first engine 51a and the second engine 51b can be operated with different supply gas pressures. Further, when starting the gas operation of the second engine 51b, the supply gas to the first engine 51a during the gas operation is adjusted by adjusting the first pressure adjustment valve 61a and the second pressure adjustment valve 61b. The supply gas pressure to the second engine 51b can be increased while suppressing the pressure fluctuation within an allowable range. Thereby, the gas operation of the second engine 51b can be started while the gas supply to the first engine 51a during the gas operation is stably continued.

Further, during the gas operation of the second engine 51b, the second on-off valve 93 is closed and the bleed valve 95 is opened, so that the buffer tank 91 can be set to a low pressure, and a sudden pressure increase in the gas supply line occurs. It can cope with the case. Further, the second on-off valve 93 can be opened, the bleed valve 95 can be closed, and the pressure in the buffer tank 91 can be made the same as the supply gas pressure to the second engine 51b, which is caused by a sudden increase in engine output. Pressure fluctuation can be reduced.

Such switching from the oil operation to the gas operation has been described with respect to the ship 1F according to the sixth embodiment, but the first to fifth embodiments can also be performed by performing the same control as described above. Further, the above control method for switching between the oil operation and the gas operation is merely an example, and is not necessarily limited to the above control method, for example, timing for opening and closing the first on-off valve 92 and the second on-off valve 93.

<Other embodiments>
The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the present invention.

For example, in the ship gas supply system according to the above-described embodiment, the high-pressure pump 41 is configured so that the evaporation gas supplied to the first engine 51a and the second engine 51b is higher than the required pressure (for example, 15 to 30 MPa). Although the pressure of the liquefied gas supplied from the tank 2 is increased, the pressure increasing device of the present invention is not limited to the high pressure pump 41.

For example, FIG. 7 shows a modification of the gas supply system 10A in the ship according to the first embodiment. The gas supply system 10A ′ of FIG. 7 includes a tank 2 that stores liquefied gas, and a compressor that boosts the boil-off gas that has accumulated in the upper portion of the tank 2 as a result of vaporization of the liquefied gas in the tank 2 (of the booster of the present invention). One example) 46 and a gas supply line 3 extending from the compressor 46 to the

engines

51a and 51b. The gas supply line 3 includes a main flow path 31 connected to the compressor 46 and two branch paths (first branch path 32 and second branch path 33) communicating with the main flow path 31. Further, the gas supply system 10A ′ includes a reflux line 48 branched from the downstream side portion of the compressor 46 in the main flow path 31 of the gas supply line 3 and connected to the tank 2, a flow rate control valve 49 provided in the reflux line 48, and A reliquefaction device 47 is provided. The boil-off gas in the tank 2 is pressurized by the compressor 46 so that the evaporated gas supplied to the engine becomes higher than the required pressure. By adjusting the flow control valve 49, a part of the evaporated gas whose pressure has been increased by the compressor 46 can be reliquefied by the reliquefaction device 47 and returned to the tank 2. A ship 1A 'having such a gas supply system 10A' can obtain the same effects as those of the first embodiment. Further, the gas supply system 10A ′ including the compressor 46 can be applied to the second to sixth embodiments.

In the above embodiment, the

engines

51a and 51b are configured to diffuse and burn gas in the case of gas operation, but the present invention is not limited to this. For example, the

engines

51a and 51b may be configured to premix and burn gas in the case of gas operation. When the

engines

51a and 51b are configured to perform premixed combustion, the required pressure of the

engines

51a and 51b may be low, or a simple booster that boosts the required pressure may be used. .

In the above embodiment, a two-machine two-shaft type ship has been described as an example of a ship equipped with a plurality of diesel engines that drive a main shaft provided with a propeller. However, the ship of the present invention is not limited to this. . The ship of the present invention may be, for example, a 3-machine 3-axis ship, a 4-machine 4-axis ship, or a 2-machine 1-axis or 4-machine 2-axis ship using a gear device.

The description of the third embodiment described above also applies to a ship equipped with three or more engines. In this case, the above-mentioned “first branch path” means an arbitrary one of the plurality of branch paths, and “second branch path” means the first branch of the plurality of branch paths. It means any one branch path different from the road. For example, in the case of a three-machine three-axis ship where the gas supply line includes three branch paths, the ship of the present invention is provided with a cross feed line between only two of the three branch paths. This includes not only a ship but also a ship in which a cross feed line is provided between any two of the three branches.

The above description of the fourth and sixth embodiments is also applicable to a ship equipped with three or more engines. In this case, the above-mentioned “first branch path” means any one of the plurality of branch paths, and “second branch path” means the first branch path among the plurality of branch paths. Means any one other branch path. For example, in the case of a three-machine three-axis ship where the gas supply line includes three branch paths, the ship of the present invention is provided with a cross feed line between only two of the three branch paths. This includes not only a ship but also a ship in which a cross-feed line is provided between any two of the three branches, and the ship of the present invention includes, for example, each of the three branches. A cross feed line extending to one common buffer tank is provided, and a ship in which an open / close valve is provided in each cross feed line is also included. Further, the ship according to the first to third embodiments may not include a buffer tank.

Furthermore, the configurations in FIGS. 2 to 6 can be appropriately combined. For example, the

bypass channels

34a and 34b and the

pressure regulating valves

62a and 62b shown in FIG. 2 may be added to the configurations in FIGS. .

INDUSTRIAL APPLICABILITY The present invention can be applied to a multi-machine / multi-shaft type ship in which a diesel engine using gas as a fuel is used as a propulsion main unit, a plurality of main units are mounted, and a main shaft provided with a propeller is provided in each main unit. .

1A to 1F Ship 10A to 10F Gas supply system 2 Tank 3 Gas supply line 31

Main flow path

32, 33

Branch path

34a, 34b Bypass flow path 41 High-pressure pump (pressure booster)
42 Vaporizer 43 Flow control valve 44

Recirculation line

51a,

51b Engine

52a,

52b Main shaft

53a,

53b Propeller

54a, 54b

Oil supply line

61a, 61b

Pressure adjustment valve

62a, 62b

Pressure adjustment valve

71a,

71b Buffer tank

73a, 73b Open /

close valve

74a,

74b Bleed valve

75a, 75b Bleed line 81 Cross feed valve 82 Cross feed line 91

Buffer tank

92, 93 On-off valve 94 Cross feed line 95 Bleed valve 96 Bleed line

Claims

A tank for storing liquefied gas;
A plurality of diesel engines that drive a main shaft provided with a propeller, using the evaporated gas vaporized from the liquefied gas as fuel;
A booster that boosts the liquefied gas or evaporative gas supplied from the tank so that the evaporative gas supplied to the diesel engine is higher than the highest required pressure among the required pressures of the plurality of diesel engines;
A supply line extending from the booster to the plurality of diesel engines, including a main flow path connected to the booster and a plurality of branches connected to the plurality of diesel engines;
And a pressure regulating valve provided in each of the plurality of branch paths.
The ship according to claim 1, wherein the booster is a pump that boosts the liquefied gas, and the main flow path is provided with a vaporizer that vaporizes the liquefied gas discharged from the pump.
A control device for controlling the pressure regulating valve according to the pressure required by each of the plurality of diesel engines;
A reflux line branched from a portion between the pump and the vaporizer in the main flow path and connected to the tank;
A flow rate control valve provided in the reflux line,
The marine vessel according to claim 2, wherein the control device controls the pump and the flow control valve according to a pressure required by each of the plurality of diesel engines.
A bypass passage communicating the primary side and the secondary side of the pressure regulating valve;
The ship according to any one of claims 1 to 3, further comprising a pressure regulating valve or an on-off valve provided in the bypass flow path.
A plurality of buffer tanks respectively communicating with the plurality of branch paths on the downstream side of the pressure regulating valve;
An on-off valve provided in a communication portion between the downstream portion of the pressure regulating valve in each of the plurality of branch paths and each of the plurality of buffer tanks;
A bleed line connected to each of the plurality of buffer tanks;
The marine vessel according to any one of claims 1 to 3, further comprising a bleed valve provided on the bleed line.
A downstream portion of the pressure regulating valve in the first branch path of the plurality of branch paths, and a downstream portion of the pressure regulating valve in a second branch path different from the first branch path of the plurality of branch paths; A cross feed line that communicates with
The ship according to any one of claims 1 to 3, further comprising a cross feed valve provided in the cross feed line.
The downstream portion of the pressure regulating valve in the first branch path of the plurality of branch paths and the downstream portion of the pressure regulating valve in the second branch path different from the first branch path of the plurality of branch paths. A cross-feed line that communicates with
A buffer tank provided in the cross-feed line;
A first on-off valve provided in a portion of the cross feed line between the buffer tank and the first branch path;
The marine vessel according to any one of claims 1 to 3, further comprising a second on-off valve provided at a portion of the cross feed line between the buffer tank and the second branch path.
A bleed line connected to the buffer tank of the cross-feed line;
The ship according to claim 7, further comprising a bleed valve provided in the bleed line.
The diesel engine can be switched between an oil operation using only oil as a fuel and a gas operation using only gas or both oil and gas as fuel. In the case of oil operation, the oil is diffusely burned and gas operation is performed. The ship according to any one of claims 1 to 3, which is a dual fuel diesel engine that diffuses and burns gas.
The diesel engine can be switched between an oil operation using only oil as a fuel and a gas operation using only gas or both oil and gas as fuel. In the case of oil operation, the oil is diffusely burned and gas operation is performed. The ship according to any one of claims 1 to 3, which is a dual fuel diesel engine that premixes and burns gas.
The ship according to any one of claims 1 to 3, wherein when the diesel engine is operated with gas fuel, a required pressure changes according to an output of the diesel engine.