WO2017077719A1

WO2017077719A1 - Ship

Info

Publication number: WO2017077719A1
Application number: PCT/JP2016/004816
Authority: WO
Inventors: 直樹成島; 崇嗣安部; 康平橋本; 安藤　明洋; 宏之武田; 尚子印藤
Original assignee: 川崎重工業株式会社
Priority date: 2015-11-06
Filing date: 2016-11-04
Publication date: 2017-05-11

Abstract

The ship is equipped with: a main gas engine for propulsion; a tank for storing liquefied natural gas; a gas delivery line for guiding boil-off gas generated inside the tank to a compressor; a first supply line for guiding the boil-off gas discharged from the compressor to the main gas engine; an auxiliary gas engine for generating electric power; a liquid delivery line for guiding the liquefied natural gas discharged from a pump disposed inside the tank to a forcible vaporizer; a second supply line for guiding the vaporized gas generated by the forcible vaporizer to the auxiliary gas engine; a bridge line for guiding the boil-off gas from the compressor to the second supply line; a first regulation valve which is disposed on the liquid delivery line, the opening degree of which can be changed; a second regulation valve which is disposed on the bridge line, the opening degree of which can be changed; and a control device for controlling the first regulation valve and the second regulation valve.

Description

Ship

The present invention relates to a ship including a main gas engine for propulsion and a sub gas engine for power generation.

2. Description of the Related Art Conventionally, for example, a fuel gas supply system shown in Patent Document 1 is known that is used in ships including a propulsion main gas engine and a power generation sub-gas engine. In this fuel gas supply system, liquefied gas is loaded in a cargo tank. The boil-off gas naturally generated in the tank is supplied to the main engine through a first fuel gas supply line including a high-pressure gas compressor. Further, the low pressure gas is supplied to the diesel power generation engine through the low pressure fuel gas supply line branched from the high pressure gas compressor. Furthermore, the liquefied gas is pressurized by the high-pressure liquid pump through the second fuel gas supply line connected to the pump in the tank, and is heated and vaporized by the gas heater. The vaporized gas (vaporized gas) is supplied from the second fuel gas supply line to the main engine through the first fuel gas supply line, and from the second fuel gas supply line to the first fuel gas supply line, the communication line, and the low pressure. It is supplied to the diesel generator engine through the fuel gas supply line.

In this system, the intersection of the curve showing the relationship between ship speed and fuel consumption and a straight line showing the amount per unit time (tank generation amount) that the liquefied gas in the tank spontaneously evaporates and becomes boil-off gas. It is calculated as an operating point. In operation at this operating point and at a lower speed than the operating point, boil-off gas is supplied to the main engine, and surplus boil-off gas is supplied to the diesel power generation engine or boiler. On the other hand, in operation at a higher speed than the operating point, boil-off gas is supplied to the main engine and the diesel generator engine, and vaporized gas is supplied to the main engine and the diesel generator as fuel that is insufficient for this.

Japanese Patent Laying-Open No. 2015-145243

In the above fuel gas supply system, boil-off gas and / or vaporized gas is supplied to the diesel generator according to the relationship between the fuel consumption and the amount of tank generated. However, it does not describe control for supplying boil-off gas and / or vaporized gas to the diesel generator at a pressure according to the demand. For this reason, the fuel gas supply system still has room for improvement from the viewpoint of supplying the boil-off gas and / or the vaporized gas to the diesel generator at a pressure according to the demand.

Therefore, an object of the present invention is to provide a ship capable of supplying boil-off gas and / or vaporized gas to a sub-gas engine for power generation at a pressure according to the demand.

In order to solve the above problems, a ship according to the first aspect of the present invention includes a main gas engine for propulsion, a tank that stores liquefied natural gas, and a boil-off gas that is generated in the tank that leads to a compressor. A gas line, a first supply line for guiding boil-off gas discharged from the compressor to the main gas engine, a sub-gas engine for power generation, and liquefied natural gas discharged from a pump disposed in the tank. A liquid feed line leading to the forced vaporizer, a second supply line leading the vaporized gas generated in the forced vaporizer to the sub-gas engine, and a bridge leading the boil-off gas from the compressor to the second supply line Line, a first adjustment valve provided in the liquid supply line capable of changing an opening degree, a second adjustment valve provided in the bridge line capable of changing an opening degree, and the first adjustment valve And a control unit for controlling the preliminary second regulating valve, the.

According to the configuration of the ship according to the first aspect, the liquefied natural gas led to the liquid feeding line is vaporized by the forced vaporizer, and this vaporized gas is led to the second supply line and supplied to the sub gas engine. . Further, when the boil-off gas is surplus with respect to the fuel gas consumption of the main gas engine, the surplus boil-off gas is led from the compressor to the bridge line and the second supply line and supplied to the sub gas engine. Here, the control device controls the first adjustment valve of the liquid supply line and the second adjustment valve of the bridge line, thereby adjusting the flow rate of the boil-off gas and / or the vaporized gas supplied to the auxiliary gas engine, and boil-off. Gas and / or vaporized gas can be supplied to the secondary gas engine at a pressure according to its requirements.

The ship according to the second aspect of the present invention further includes a pressure gauge for detecting the pressure of the boil-off gas in the tank or the boil-off gas flowing in the air supply line, and the control device is configured to supply liquefied natural gas in the tank. When the available amount of boil-off gas is larger than the amount of fuel gas consumed by the main gas engine, the available amount of boil-off gas is calculated from the amount and the pressure of the boil-off gas detected by the pressure gauge. 2 You may open a regulating valve.

According to the configuration of the ship according to the second aspect, surplus boil-off gas with respect to the fuel gas consumption of the main gas engine can be flowed to the bridge line via the second adjustment valve and supplied to the auxiliary gas engine. Note that opening the second adjustment valve includes opening the closed second adjustment valve and maintaining the opened second adjustment valve in advance.

In the ship according to the third aspect of the present invention, the control device may calculate a difference between an available amount of the boil-off gas and a sum of a fuel gas consumption amount of the main gas engine and a fuel gas consumption amount of the sub gas engine. The first regulating valve may be controlled accordingly, and the second regulating valve may be controlled according to the fuel gas demand pressure of the auxiliary gas engine. Further, in the ship according to the fourth aspect of the present invention, the control device controls the second regulating valve according to a difference between an available amount of the boil-off gas and a fuel gas consumption amount of the main gas engine, The first regulating valve may be controlled in accordance with a fuel gas demand pressure of the auxiliary gas engine.

According to the configuration of the ship according to the third and fourth aspects, the amount of boil-off gas generated varies depending on the pressure of the boil-off gas in the tank, but substantially depends on the amount of liquefied natural gas in the tank. For this reason, when the amount of boil-off gas supplied to the compressor is determined by comparing the fuel gas consumption of the main gas engine with the amount of boil-off gas generated, the pressure of the boil-off gas in the tank is within an arbitrary required range. It is difficult to adjust. On the other hand, the available amount of boil-off gas is calculated from the amount of liquefied natural gas in the tank and the pressure of the boil-off gas detected by the pressure gauge. Depending on the difference between the available amount and the sum of the fuel gas consumption of the main gas engine and the fuel gas consumption of the auxiliary gas engine, or the difference between the available amount and the fuel gas consumption of the main gas engine, If the control valve is controlled, the boil-off gas may be actively used when the pressure of the boil-off gas in the tank is high, and the amount of boil-off gas used may be reduced when the pressure of the boil-off gas in the tank is low. it can. Therefore, the pressure of the boil-off gas in the tank can be easily adjusted within the required range.

The ship according to the fifth aspect of the present invention branches from the first supply line or the second supply line and is connected to the tank. The return line is provided with an expansion device, and the opening is provided in the return line. A third adjusting valve that can be changed, and the control device may control the third adjusting valve. According to the structure of the ship which concerns on a 5th aspect, surplus boil-off gas with respect to the sum of each fuel gas consumption of a main gas engine and a subgas engine can be returned to a tank through a return line.

The ship according to the sixth aspect of the present invention further includes a pressure gauge for detecting the pressure of the boil-off gas in the tank or the boil-off gas flowing in the air supply line, and the control device is configured to supply liquefied natural gas in the tank. The available amount of boil-off gas is calculated from the amount and the pressure of the boil-off gas detected by the pressure gauge, and the available amount of boil-off gas is the fuel gas consumption amount of the main gas engine and the fuel gas consumption of the auxiliary gas engine. When it is larger than the sum of the amounts, the second adjustment valve and the third adjustment valve may be opened.

According to the configuration of the ship according to the sixth aspect, surplus boil-off gas with respect to the fuel gas consumption of the main gas engine can be flowed to the bridge line via the second adjustment valve and supplied to the auxiliary gas engine. Moreover, surplus boil-off gas with respect to the sum of the fuel gas consumption of each gas engine can be sent to a return line via a 3rd regulating valve, and can be returned to a tank. Note that opening the second adjustment valve and the third adjustment valve means opening the closed second adjustment valve and the third adjustment valve, and opening the second adjustment valve and the third adjustment valve that are opened in advance. Including maintaining.

In the ship according to the seventh aspect of the present invention, the control device responds to a difference between an available amount of the boil-off gas and a sum of a fuel gas consumption amount of the main gas engine and a fuel gas consumption amount of the sub gas engine. The third adjustment valve may be controlled, and the second adjustment valve may be controlled in accordance with the fuel gas required pressure of the auxiliary gas engine.

According to the configuration of the ship according to the seventh aspect, if the third regulating valve is controlled according to the difference between the available amount of boil-off gas and the sum of the fuel gas consumption of each gas engine, the boil-off gas in the tank The pressure can be easily adjusted within the required range. Further, if the second regulating valve is controlled according to the fuel gas required pressure of the auxiliary gas engine, the boil-off gas and / or the vaporized gas can be supplied to the auxiliary gas engine at a pressure corresponding to the requirement.

According to the present invention, boil-off gas and / or vaporized gas can be supplied to the sub-gas engine for power generation at a pressure according to the demand.

1 is a schematic configuration diagram of a ship according to a first embodiment of the present invention. It is a graph which shows the relationship between the deviation of the pressure of the boil-off gas in a tank, and setting pressure, and the available amount of boil-off gas. It is a schematic block diagram of the ship which concerns on 2nd Embodiment of this invention. It is a schematic block diagram of the ship which concerns on 3rd Embodiment of this invention. It is a schematic block diagram of the ship which concerns on 4th Embodiment of this invention. It is a schematic block diagram of the ship which concerns on 5th Embodiment of this invention.

(First embodiment)
FIG. 1 shows a ship 1A according to the first embodiment of the present invention. The ship 1A includes a tank 11 for storing liquefied natural gas (hereinafter referred to as LNG), a main gas engine 13 for propulsion, and a sub gas engine 16 for power generation (that is, for onboard power).

In the illustrated example, only one tank 11 is provided, but a plurality of tanks 11 may be provided. In the present embodiment, the ship 1A is an LNG carrier, and the ship 1A is equipped with a plurality of cargo tanks. That is, the tank 11 shown in FIG. 1 is each of a plurality of cargo tanks. In the illustrated example, one main gas engine 13 and one sub gas engine 16 are provided, but a plurality of main gas engines 13 may be provided, or a plurality of sub gas engines 16 may be provided. Good.

In this embodiment, the ship 1A is a mechanical propulsion type, and the main gas engine 13 directly rotates and drives a screw propeller (not shown). However, the ship 1A may be an electric propulsion type, and the main gas engine 13 may rotationally drive the screw propeller via a generator and a motor.

The main gas engine 13 is a diesel cycle type two-stroke engine having a high fuel gas injection pressure of about 20 to 35 MPa, for example. However, the main gas engine 13 may be an Otto cycle type two-stroke engine having a medium pressure of, for example, a fuel gas injection pressure of about 1 to 2 MPa. Alternatively, in the case of electric propulsion, the main gas engine 13 may be an Otto cycle type four-stroke engine having a low fuel gas injection pressure of, for example, about 0.5 to 1 MPa. The main gas engine 13 may be a gas-only combustion engine that burns only fuel gas, or may be a dual fuel engine that burns one or both of fuel gas and fuel oil (binary fuel engine). In this case, the fuel gas may be burned by the Otto cycle, and the fuel oil may be burned by the diesel cycle).

The auxiliary gas engine 16 is an Otto cycle type four-stroke engine having a low fuel gas injection pressure of about 0.5 to 1 MPa, for example, and is connected to a generator (not shown). The auxiliary gas engine 16 may be a gas combustion engine that burns only fuel gas, or may be a dual fuel engine that burns one or both of fuel gas and fuel oil.

The fuel gas of the main gas engine 13 is mainly boil-off gas (hereinafter referred to as BOG) generated in the tank 11 by natural heat input, and the fuel gas of the auxiliary gas engine 16 is mainly forced by LNG. The vaporized gas (hereinafter referred to as VG).

Specifically, the tank 11 is connected to the compressor 12 by an air supply line 21, and the compressor 12 is connected to the main gas engine 13 by a first supply line 22. Further, a pump 14 is disposed in the tank 11, and the pump 14 is connected to the forced vaporizer 15 by a liquid feed line 31. The forced vaporizer 15 is connected to the auxiliary gas engine 16 by the second supply line 32.

The air supply line 21 guides BOG generated in the tank 11 to the compressor 12. The compressor 12 compresses the BOG to a high pressure. The first supply line 22 guides high-pressure BOG discharged from the compressor 12 to the main gas engine 13.

In this embodiment, the compressor 12 is a five-stage high-pressure compressor. A connection line 12b connects between the inlet of the compressor 12 and the first stage compression unit 12a, between each stage compression unit 12a, and between the outlet of the compressor 12 and the fifth stage compression unit 12a. Has been. A bypass line 12c that bypasses each compressor 12a is connected to the connection line 12b, and a bypass valve 12d is provided in the bypass line 12c. The bypass valve 12 d is an adjustment valve whose opening degree can be changed, and the opening degree is controlled by the control device 6. The compressor 12 may be a low-pressure compressor, for example, when the fuel gas injection pressure of the main gas engine 13 is low.

The bridge line 51 is connected from the compressor 12 to the second supply line 32. In the compressor 12, the bridge line 51 is connected to a stage where the pressure of the BOG in the bridge line 51 becomes higher than the required fuel gas pressure of the auxiliary gas engine 16. However, the larger the pressure difference, the more expensive the pressure adjusting device such as a pressure reducing valve for adjusting the pressure of the BOG supplied to the sub gas engine 16 to the required fuel gas pressure of the sub gas engine 16. For this reason, in consideration of pressure and cost, in this embodiment, the bridge line 51 is connected to the compressor 12 between the second-stage compression unit 12a and the third-stage compression unit 12a. The bridge line 51 guides this surplus BOG from the compressor 12 to the second supply line 32 when the BOG is surplus with respect to the fuel gas consumption of the main gas engine 13. In that case, the auxiliary gas engine 16 is supplied with VG and BOG (in some cases, only BOG) as fuel gas.

The liquid feed line 31 guides LNG discharged from the pump 14 to the forced vaporizer 15. The pump 14 discharges LNG so that the pressure of VG guided from the forced vaporizer 15 to the auxiliary gas engine 16 becomes equal to or higher than the required fuel gas pressure of the auxiliary gas engine 16. The forced vaporizer 15 forcibly vaporizes LNG using, for example, steam generated in a boiler as a heat source, and generates VG. The second supply line 32 guides VG generated by the forced vaporizer 15 to the auxiliary gas engine 16. The second supply line 32 is preferably provided with equipment (for example, a cooler and a gas-liquid separator) for removing heavy components such as ethane having a mass larger than that of methane from the VG. . As a result, VG having a high methane number can be supplied to the auxiliary gas engine 16.

Further, a check valve 33 is provided on the second supply line 32 upstream of the connection point of the bridge line 51. Thereby, when the pressure of VG flowing into the second supply line 32 from the forced vaporizer 15 is lower than the pressure of BOG flowing into the second supply line 32 from the bridge line 51, the BOG flowing from the bridge line 51 is forced to the forced vaporizer 15. Backflow is prevented. Note that the check valve 33 may not be provided in the second supply line 32. In addition, a check valve that prevents BOG or VG from flowing back to the compressor 12 may be provided in the bridge line 51.

The liquid supply line 31 is provided with a first adjustment valve 31a, and the bridge line 51 is provided with a second adjustment valve 51a. The opening degree of these regulating

valves

31 a and 51 a can be changed, and the opening degree is controlled by the control device 6. In FIG. 1, only some signal lines are drawn for the sake of simplicity.

In the present embodiment, the first adjustment valve 31a plays a role of opening and closing the liquid supply line 31, and the second adjustment valve 51a plays a role of opening and closing the bridge line 51. However, an opening / closing valve may be provided in the liquid feeding line 31 separately from the first adjustment valve 31a, or an opening / closing valve may be provided in the bridge line 51 separately from the second adjustment valve 51a.

Furthermore, a first pressure gauge 61 for detecting the pressure Pb1 of the BOG flowing through the air supply line 21 is provided in the air supply line 21. However, the first pressure gauge 61 may be provided in the tank 11 and detect the pressure of the BOG in the tank 11. Further, the first supply line 22 is provided with a second pressure gauge 62 that detects the pressure Pb2 of the BOG flowing through the first supply line 22. A flow meter 63 that detects the flow rate Fl of LNG flowing through the liquid supply line 31 is provided in the liquid supply line 31. In FIG. 1, the flow meter 63 is provided in the liquid supply line 31 on the upstream side of the first adjustment valve 31a, but may be provided in the liquid supply line 31 on the downstream side of the first adjustment valve 31a. Good. Further, the flow meter 63 may be provided downstream of the forced vaporizer 15 in the second supply line 32 and upstream of the connection point of the bridge line 51. In this case, the flow meter 63 detects the flow rate of VG flowing from the forced vaporizer 15 to the second supply line 32. Further, the second supply line 32 is provided with a third pressure gauge 64 for detecting the pressure Pv of VG and / or BOG flowing through the second supply line 32. The third pressure gauge 64 is located downstream of the connection point of the bridge line 51 in the second supply line 32.

The control device 6 supplies the fuel gas (BOG and / or VG) to each

gas engine

13 and 16 at the required fuel gas pressure of each

gas engine

13 and 16 and keeps the pressure in the tank 11 within the required range. The

control valves

31a and 51a are controlled based on the detected values of the flow meter 63 and the pressure gauges 61, 62 and 64. The required fuel gas pressure of each

gas engine

13, 16 is a pressure determined in advance or arbitrarily according to the request of each

gas engine

13, 16. Further, the required range of the internal pressure of the tank 11 is a pressure determined in advance or arbitrarily according to the performance of the tank 11 or the like.

Specifically, the control device 6 controls the pressure of the BOG supplied to the main gas engine 13 based on the detection value of the second pressure gauge 62. In other words, the detection value signal is transmitted from the second pressure gauge 62 to the control device 6. Based on this detected value, the control device 6 acquires the pressure Pb2 of BOG that is pumped from the compressor 12 and supplied to the main gas engine 13 via the first supply line 22. The control device 6 controls the bypass valve 12d of the compressor 12 so that the BOG pressure Pb2 becomes the required fuel gas pressure of the main gas engine 13. As a result, BOG is supplied to the main gas engine 13 at the required fuel gas pressure of the main gas engine 13.

Further, the control device 6 controls the pressures of VG and BOG supplied to the auxiliary gas engine 16 based on the detected values of the first pressure gauge 61, the third pressure gauge 64, and the flow meter 63. Therefore, first, the control device 6 calculates the fuel gas consumption amount Q1 of the main gas engine 13 and the fuel gas consumption amount Q2 of the auxiliary gas engine 16.

That is, the control device 6 includes a first gas engine controller (not shown) for controlling the fuel gas injection timing of the main gas engine 13 and the second gas engine for controlling the fuel gas injection timing of the auxiliary gas engine 16. Various signals are transmitted from a controller (not shown). Then, the control device 6 calculates the fuel gas consumption Q1 of the main gas engine 13 from the signal transmitted from the first gas engine controller, and the auxiliary gas engine 16 from the signal transmitted from the second gas engine controller. The fuel gas consumption Q2 is calculated. However, the control device 6 may acquire the fuel gas consumption Q1 directly from the first gas engine controller. Further, the control device 6 may acquire the fuel gas consumption Q2 directly from the second gas engine controller.

Next, the control device 6 calculates the available amount Qa of BOG from the amount of LNG in the tank 11 and the BOG pressure Pb 1 detected by the first pressure gauge 61. That is, a detection value signal is transmitted from the first pressure gauge 61 to the control device 6. Then, the control device 6 adds the pressure loss from the upstream end of the air supply line 21 to the position of the first pressure gauge 61 to the pressure Pb1 of the BOG based on the detected value, and the pressure of the BOG in the tank 11 Pt is calculated. As the deviation ΔP (= Pt−Ps) between the BOG pressure Pt in the tank 11 and the set pressure Ps increases, the BOG usable amount Qa increases as shown in FIG. Here, the set pressure Ps is a pressure at which the BOG usable amount Qa becomes equal to the BOG generation amount Qn. The BOG generation amount Qn varies depending on the pressure of the BOG in the tank 11, but substantially depends on the amount of LNG in the tank 11.

When the capacity of the tank 11 is very large like a cargo tank, even if BOG and / or LNG is used as the fuel gas, the height of the liquid level of the LNG in the tank 11 does not change so much. For this reason, in this embodiment, the amount of LNG in the tank 11 is treated as a constant value, not as a variable. However, when the capacity of the tank 11 is small, a level meter that detects the amount of LNG in the tank 11 may be provided in the tank 11 and the amount of LNG in the tank 11 may be treated as a variable. Then, the control device 6 calculates the available amount Qa of BOG from the amount of LNG in the tank 11 and the pressure deviation ΔP.

Next, the control device 6 compares the available amount Qa of the BOG with the fuel gas consumption amounts Q1 and Q2 of the

gas engines

13 and 16, respectively. When the available amount Qa of BOG is larger than the fuel gas consumption amount Q1 of the main gas engine 13 (when BOG is more than the fuel gas consumption amount Q1 of the main gas engine 13), the control device 6 uses the available amount Qa. The difference ΔQ1 (= Qa−Q1) between the fuel gas consumption amount Q1 and the surplus BOG amount is obtained. Further, when the difference ΔQ1 is equal to or smaller than the fuel gas consumption Q2 of the auxiliary gas engine 16 (ΔQ1 ≦ Q2), the control device 6 determines the difference ΔQ2 (= between the fuel gas consumption Q2 of the auxiliary gas engine 16 and the difference ΔQ1). Q2-ΔQ1) is calculated. And the control apparatus 6 calculates | requires the flow volume of VG which flows into the 2nd supply line 32 from the forced vaporizer 15 from the flow volume Fl detected by the flowmeter 63, and is 1st so that this VG flow volume may become difference (DELTA) Q2. The opening degree of the regulating valve 31a is controlled. Thereby, VG of ΔQ2 flows from the forced vaporizer 15 to the second supply line 32, and surplus BOG of ΔQ1 flows from the bridge line 51 to the second supply line 32.

Further, the control device 6 controls the opening degree of the second adjustment valve 51 a so that the pressure Pv detected by the third pressure gauge 64 becomes the required fuel gas pressure of the auxiliary gas engine 16. As a result, VG and BOG are supplied to the auxiliary gas engine 16 at the required fuel gas pressure of the auxiliary gas engine 16.

As described above, in the marine vessel 1A of the present embodiment, LNG is forcibly vaporized by the forced vaporizer 15 and the VG is supplied to the secondary gas engine 16, so that the secondary gas engine is not used without using a high-pressure pump. 16 can be supplied with a sufficient amount of fuel gas.

When the BOG is surplus with respect to the fuel gas consumption Q 1 of the main gas engine 13, the surplus BOG can be supplied from the compressor 12 to the sub gas engine 16 through the bridge line 51 and the second supply line 32. Accordingly, the amount of VG vaporized by the forced vaporizer 15 can be reduced, and the amount of heat used for forced vaporization by the forced vaporizer 15 can be suppressed.

As described above, the BOG generation amount Qn varies depending on the pressure of the BOG in the tank 11, but substantially depends on the amount of LNG in the tank 11. Therefore, when the first adjustment valve 31a is controlled by comparing the fuel gas consumption amount Q1 of the main gas engine 13 with the BOG generation amount Qn, the pressure of the BOG in the tank 11 is adjusted within an arbitrary required range. Difficult to do. In contrast, in the present embodiment, the available amount Qa of BOG is calculated from the amount of LNG in the tank 11 and the BOG pressure Pb 1 detected by the pressure gauge 61. Then, the first regulating valve 31a is controlled in accordance with the difference ΔQ2 between the available amount Qa of BOG and the sum of the fuel gas consumption Q1 of the main gas engine 13 and the fuel gas consumption Q2 of the auxiliary gas engine 16. . Thereby, since the flow rate of BOG flowing from the tank 11 to the bridge line 51 via the air supply line 21 and the compressor 12 is controlled, the pressure of the BOG in the tank 11 can be indirectly adjusted within the required range. it can.

Further, the first adjustment valve 31a is controlled according to the difference ΔQ2, and the second adjustment valve 51a is controlled according to the fuel gas required pressure of the auxiliary gas engine 16. As a result, VG and BOG are supplied to the auxiliary gas engine 16 at the required fuel gas pressure of the auxiliary gas engine 16. Further, the bypass valve 12 d of the compressor 12 is controlled according to the fuel gas required pressure of the main gas engine 13. As a result, BOG is supplied to the main gas engine 13 at the required fuel gas pressure of the main gas engine 13.

(Second Embodiment)
Next, with reference to FIG. 3, the ship 1B which concerns on 2nd Embodiment of this invention is demonstrated. In addition, in this embodiment and each embodiment mentioned later, the same code | symbol is attached | subjected to the same component as 1st Embodiment, and the overlapping description is abbreviate | omitted.

In the first embodiment, the flow meter 63 is provided in the liquid feeding line 31. On the other hand, in the second embodiment, the flow meter 65 is provided on the bridge line 51. In the first embodiment, the control device 6 controls the first adjustment valve 31a according to the difference ΔQ2, and controls the second adjustment valve 51a according to the fuel gas required pressure of the auxiliary gas engine 16. On the other hand, in 2nd Embodiment, the control apparatus 6 controls the 2nd adjustment valve 51a according to difference (DELTA) Q1, and controls the 1st adjustment valve 31a according to the fuel gas request | requirement pressure of the subgas engine 16. FIG.

Specifically, the flow meter 65 detects the BOG flow rate Fb 1 flowing from the compressor 12 to the bridge line 51. This detected value is transmitted to the control device 6.

The control device 6 controls the pressure of the BOG supplied to the main gas engine 13 based on the fuel gas consumption Q1 of the main gas engine 13 and the detected value of the second pressure gauge 62. The control device 6 also supplies VG and BOG supplied to the auxiliary gas engine 16 based on the detected values of the fuel gas consumption Q2 of the auxiliary gas engine 16, the first pressure gauge 61, the third pressure gauge 64, and the flow meter 65. To control the pressure.

In this pressure control of VG and BOG, the available amount Qa of BOG is larger than the fuel gas consumption amount Q1 of the main gas engine 13 and is equal to or less than the sum of the fuel gas consumption amounts Q1 and Q2 of the

gas engines

13 and 16. In the case (Q1 <Qa ≦ Q1 + Q2), the difference ΔQ1 (= Qa−Q1) between the BOG usable amount Qa and the fuel gas consumption Q1 of the main gas engine 13 is calculated. And the control apparatus 6 controls the opening degree of the 2nd adjustment valve 51a so that the flow volume Fb1 detected by the flowmeter 65 may become difference (DELTA) Q1. Thereby, surplus BOG of the flow rate Fb1 flows from the compressor 12 to the bridge line 51. Further, the control device 6 controls the opening degree of the first adjustment valve 31 a so that the pressure Pv detected by the third pressure gauge 64 becomes the required fuel gas pressure of the auxiliary gas engine 16. As a result, VG and BOG are supplied to the auxiliary gas engine 16 at the required fuel gas pressure.

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

In the second embodiment, the control device 6 controls the opening degree of the first adjustment valve 31a so that the pressure Pv detected by the third pressure gauge 64 becomes the required fuel gas pressure of the auxiliary gas engine 16. . Instead, the control device 6 calculates the difference (Q1 + Q2-Qa) between the sum of the fuel gas consumption amount Q1 of the main gas engine 13 and the fuel gas consumption amount Q2 of the auxiliary gas engine 16 and the available amount Qa of BOG. The first adjustment valve 31a is controlled as the set flow rate of LNG. And the control apparatus 6 correct | amends the setting flow volume of LNG based on the pressure Pv detected by the 3rd pressure gauge 64, and controls the opening degree of the 1st adjustment valve 31a according to this corrected setting flow volume. Good.

(Third embodiment)
Next, a ship 1C according to a third embodiment of the present invention will be described with reference to FIG. A ship 1C according to the third embodiment further includes a return line 23 in addition to the configuration of the ship 1A according to the first embodiment. At this time, in the first embodiment, the flow meter 63 is provided in the liquid supply line 31, whereas in the third embodiment, the flow meter 66 is provided in the return line 23. The flow meter 66 detects the flow rate Fb2 of the BOG flowing through the return line 23. This detected value is transmitted to the control device 6.

The return line 23 branches from the first supply line 22 and is connected to the tank 11. The tip of the return line 23 may be located above the liquid level of LNG in the tank 11 or may be located below the liquid level. The return line 23 is provided with an expansion device 72 such as an expansion valve. The return line 23 is provided with a third adjustment valve 23a whose opening degree can be changed, and an opening / closing valve 23b for opening and closing the return line 23. The third adjusting valve 23 a and the on-off valve 23 b are controlled by the control device 6. The return line 23 may not be provided with the opening / closing valve 23b.

In the first embodiment, the available amount Qa of BOG is larger than the fuel gas consumption Q1 of the main gas engine 13 and is equal to or less than the sum of the fuel gas consumptions Q1 and Q2 of the

gas engines

13 and 16. The VG and BOG pressure control for the auxiliary gas engine 16 in (Q1 <Qa ≦ Q1 + Q2) has been described. On the other hand, in the third embodiment, when the usable amount Qa of BOG is larger than the sum of the fuel gas consumptions Q1 and Q2 of the gas engines 13 and 16 (Qa> Q1 + Q2), The pressure control will be described.

Specifically, when Qa> Q1 + Q2, the fuel gas consumptions Q1 and Q2 of the

gas engines

13 and 16 can be covered by the available amount Qa of BOG. For this reason, since it is not necessary to supply the VG which vaporized LNG with the forced vaporizer 15 to the subgas engine 16, the control apparatus 6 stops the operation of the forced vaporizer 15, and fully closes the 1st regulating valve 31a. . However, instead of fully closing the first adjustment valve 31a, the opening of the first adjustment valve 31a is set to the minimum opening at which the operation of the forced vaporizer 15 can be continued without stopping the operation of the forced vaporizer 15. Also good.

Then, the control device 6 determines the difference ΔQ3 (= Qa− (Q1 + Q2)) between the BOG usable amount Qa and the sum of the fuel gas consumption amount Q1 of the main gas engine 13 and the fuel gas consumption amount Q2 of the auxiliary gas engine 16. Is calculated. The control device 6 controls the opening degree of the third adjustment valve 23a so that the flow rate Fb2 detected by the flow meter 66 becomes the difference ΔQ3. Further, the control device 6 controls the opening degree of the second adjustment valve 51 a so that the pressure Pv detected by the third pressure gauge 64 becomes the required fuel gas pressure of the auxiliary gas engine 16. As a result, the remaining BOG of ΔQ3 with respect to the sum of the fuel gas consumptions Q1 and Q2 of the

gas engines

13 and 16 flows to the return line 23. At the same time, the BOG of the fuel gas consumption Q2 of the auxiliary gas engine 16 flows to the bridge line 51, and BOG is supplied to the auxiliary gas engine 16 at the required fuel gas pressure.

As described above, in the ship 1 </ b> C of the present embodiment, surplus BOG is returned to the tank 11 through the return line 23. Thereby, surplus BOG is not consumed wastefully. Also in this embodiment, the same effect as that of the first embodiment can be obtained.

(Fourth embodiment)
Next, with reference to FIG. 5, the ship 1D which concerns on 4th Embodiment of this invention is demonstrated. A ship 1D according to the fourth embodiment further includes a heat exchanger 81 in addition to the configuration of the ship 1C according to the third embodiment. The heat exchanger 81 is provided in the liquid supply line 31, the return line 23, and the air supply line 21. The heat exchanger 81 cools the BOG flowing in the return line 23 upstream of the expansion device 72 (BOG returned to the tank 11) by the LNG flowing in the liquid supply line 31 and the BOG flowing in the air supply line 21. After this cooling, the BOG returned to the tank 11 is partially liquefied by being expanded by the expansion device 72. On the other hand, the LNG flowing in the liquid feeding line 31 may be partially vaporized by taking heat from the BOG.

As described above, in the ship 1D of the present embodiment, the BOG flowing in the return line 23 is cooled by LNG and BOG used as fuel for the ship 1D, and thus a device and a medium for this cooling are separately prepared. There is no need to do. Also in this embodiment, the same effect as that of the first embodiment can be obtained.

(Fifth embodiment)
Next, with reference to FIG. 6, the ship 1E which concerns on 5th Embodiment of this invention is demonstrated. A ship 1E according to the fifth embodiment includes a return line 34 and a flow meter 67 instead of the return line 23 and the flow meter 66 according to the third embodiment.

The return line 34 branches off from the second supply line 32 downstream of the connection point of the bridge line 51 and is connected to the tank 11. However, the return line 34 may branch from the second supply line 32 upstream of the connection point of the bridge line 51. Moreover, the front end of the return line 34 may be located above the liquid level of LNG in the tank 11 or may be located below the liquid level. The return line 34 is provided with a third adjustment valve 34a whose opening degree can be changed. The third adjustment valve 34 a is controlled by the control device 6. Further, the flow meter 67 detects the BOG flow rate Fb3 flowing through the return line 34. This detected value is transmitted to the control device 6.

In the control of the BOG pressure with respect to the auxiliary gas engine 16, the control device 6 determines the difference between the available amount Qa of BOG and the sum of the fuel gas consumption Q1 of the main gas engine 13 and the fuel gas consumption Q2 of the auxiliary gas engine 16. ΔQ3 (= Qa− (Q1 + Q2)) is calculated. And the control apparatus 6 controls the opening degree of the 3rd adjustment valve 34a so that the flow volume Fb3 detected by the flowmeter 67 may become the difference (DELTA) Q3. Further, the control device 6 controls the opening degree of the second adjustment valve 51 a so that the pressure Pv detected by the third pressure gauge 64 becomes the required fuel gas pressure of the auxiliary gas engine 16. As a result, the remaining BOG of ΔQ1 with respect to the fuel gas consumption Q1 of the main gas engine 13 flows to the bridge line 51, and among this, the BOG of ΔQ3 flows to the return line 34. Therefore, the BOG of the fuel gas consumption Q2 of the auxiliary gas engine 16 flows to the second supply line 32 downstream of the branch point of the return line 34, and the BOG is supplied to the auxiliary gas engine 16 at the required fuel gas pressure. The

As described above, in the ship 1E of the present embodiment, surplus BOG is returned to the tank 11 through the return line 34, so that surplus BOG is not wasted. Also in this embodiment, the same effect as that of the first embodiment can be obtained.

In addition, in addition to the return line 34, the ship 1E according to the fifth embodiment may include the return line 23 according to the third embodiment. The ship 1E according to the fifth embodiment may further include a heat exchanger. This heat exchanger is provided in the liquid feed line 31 and the return line 34. The heat exchanger cools BOG flowing through the return line 34 (BOG returned to the tank 11) with LNG flowing through the liquid supply line 31.

(Other embodiments)
The present invention is not limited to the first to fifth embodiments described above, and various modifications can be made without departing from the scope of the present invention.

For example, the pump 14 may have a function of pumping up LNG up to the forced vaporizer 15, and a compressor may be provided in the second supply line 32. However, if the fuel gas injection pressure of the auxiliary gas engine 16 is secured by the pump 14, it is not necessary to provide a compressor in the second supply line 32, and the cost can be reduced.

Further, one or both of the main gas engine 13 and the auxiliary gas engine 16 are not necessarily a reciprocating engine, and may be a gas turbine engine.

Further, a bridge line that guides VG from the second supply line 32 to the air supply line 21 may be further provided. This bridge line guides VG from the second supply line 32 to the air supply line 21 when the BOG is insufficient with respect to the fuel gas consumption Q1 of the main gas engine 13. As a result, BOG and VG are supplied to the main gas engine 13 as fuel gas.

Also, flow

meters

63, 65, 66, and 67 were used for the flow control of LNG, BOG, and VG. On the other hand, it is not necessary to use a flow meter for flow control of LNG, BOG, and VG. In this case, this flow rate control is performed based on the relationship between the opening degree of each of the regulating

valves

31a, 51a, 23a, and 34a and the flow rates of LNG, BOG, and VG. Thus, this cost can be reduced by not using a flow meter.

1A to 1C: Ship 6: Control device 11: Tank 12: Compressor 13: Main gas engine 14: Pump 15: Forced vaporizer 16: Sub gas engine 21: Air supply line 22: First supply line 31: Liquid supply line 31a: First adjustment valve 32: Second supply line 23: Return line 34: Return line 23a: Third adjustment valve 51: Bridge line 51a: Second adjustment valve 61: First pressure gauge (pressure gauge)
72: expansion device 34a: third adjusting valve

Claims

A main gas engine for propulsion,
A tank for storing liquefied natural gas;
An air supply line for guiding boil-off gas generated in the tank to the compressor;
A first supply line for guiding boil-off gas discharged from the compressor to the main gas engine;
A sub-gas engine for power generation,
A liquid feed line for guiding liquefied natural gas discharged from a pump disposed in the tank to a forced vaporizer;
A second supply line that leads the vaporized gas generated in the forced vaporizer to the sub-gas engine;
A bridge line leading the boil-off gas from the compressor to the second supply line;
A first adjustment valve provided in the liquid supply line and capable of changing an opening;
A second adjusting valve provided in the bridge line, the opening degree of which can be changed;
And a control device that controls the first adjustment valve and the second adjustment valve.
A pressure gauge for detecting the pressure of the boil-off gas in the tank or the boil-off gas flowing in the air supply line;
The control device includes:
Calculate the available amount of boil-off gas from the amount of liquefied natural gas in the tank and the pressure of the boil-off gas detected by the pressure gauge,
The ship according to claim 1, wherein when the available amount of the boil-off gas is larger than the fuel gas consumption of the main gas engine, the second regulating valve is opened.
The control device controls the first regulating valve according to a difference between an available amount of the boil-off gas and a sum of a fuel gas consumption amount of the main gas engine and a fuel gas consumption amount of the sub gas engine, The marine vessel according to claim 2, wherein the second regulating valve is controlled in accordance with a fuel gas demand pressure of the auxiliary gas engine.
The control device controls the second regulating valve according to a difference between an available amount of the boil-off gas and a fuel gas consumption amount of the main gas engine, and the control device according to a fuel gas demand pressure of the sub gas engine The ship according to claim 2 which controls the 1st regulation valve.
A return line provided with an expansion device, branched from the first supply line or the second supply line and connected to the tank;
A third adjustment valve provided in the return line and capable of changing an opening;
The marine vessel according to claim 1, wherein the control device controls the third adjustment valve.
A pressure gauge for detecting the pressure of the boil-off gas in the tank or the boil-off gas flowing in the air supply line;
The control device includes:
Calculate the available amount of boil-off gas from the amount of liquefied natural gas in the tank and the pressure of the boil-off gas detected by the pressure gauge,
When the available amount of the boil-off gas is greater than the sum of the fuel gas consumption of the main gas engine and the fuel gas consumption of the auxiliary gas engine, the second adjustment valve and the third adjustment valve are opened; The ship according to claim 5.
The control device controls the third regulating valve according to a difference between an available amount of the boil-off gas and a sum of a fuel gas consumption amount of the main gas engine and a fuel gas consumption amount of the auxiliary gas engine, The ship according to claim 6 which controls said 2nd regulating valve according to fuel gas demand pressure of a subgas engine.