JP2017088154A - Ship - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ship with improved energy efficiency.SOLUTION: A ship 1A includes: a gas engine 30; a tank 10 for storing a liquefied natural gas; a solution sending line 31 which leads the liquefied natural gas discharged from a pump 11 disposed in the tank to a forced vaporizer 32; a heat exchanger 34A which conducts heat exchange between the liquefied natural gas flowing in the solution sending line and a heating medium; a supply line 33 which guides the vaporized gas generated by the forced vaporizer to the gas engine 30; a gas-liquid separator 35 which is provided in the solution sending line at a downstream side of the heat exchanger; and a bypass line 36 in which an upstream end is connected to the gas-liquid separator, a downstream end is connected to the supply line, and the vaporized gas separated by the gas-liquid separator flows.SELECTED DRAWING: Figure 1

Description

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

  Conventionally, as a ship including a main gas engine for propulsion and a sub gas engine for power generation, for example, the ship of Patent Document 1 is known. The ship includes a storage tank, a first container, a heat exchanger, and a second container. The liquefied natural gas is sent out to the first container by the liquefied gas transfer pump in the storage tank and stored therein. The liquefied natural gas is then sent to the heat exchanger by a pre-pump in the first container, where the refrigerant is cooled. The liquefied natural gas is stored in the second container, and then sent out to the vaporizer by a booster pump in the second container, where it is vaporized and supplied as natural gas to a diesel engine or the like.

JP 2009-204026 A

  In the ship, the liquefied natural gas stored in the second container is supplied to a diesel engine or the like via a vaporizer. However, liquefied natural gas is vaporized by receiving heat from the refrigerant when the refrigerant is cooled by a heat exchanger, but the use of the vaporized gas is not described. For this reason, the ship still has room for improvement from the viewpoint of improving energy efficiency.

  Then, an object of this invention is to provide the ship which aimed at the improvement of energy efficiency.

  In order to solve the above problems, a ship according to the first aspect of the present invention forcibly vaporizes liquefied natural gas discharged from a gas engine, a tank storing liquefied natural gas, and a pump disposed in the tank. A liquid feed line that leads to the vessel, a heat exchanger that exchanges heat between the liquefied natural gas flowing in the liquid feed line and the heating medium, and the vaporized gas generated by the forced vaporizer is led to the gas engine A supply line, a gas-liquid separator provided in the liquid feed line on the downstream side of the heat exchanger, an upstream end connected to the gas-liquid separator, a downstream end connected to the supply line, and And a bypass line through which the vaporized gas separated by the gas-liquid separator flows.

  According to the configuration of the ship according to the first aspect, part or all of the liquefied natural gas is vaporized by the heat exchanger. And it isolate | separates into vaporized gas and liquefied natural gas in a gas-liquid separator, and vaporized gas is supplied to a gas engine through a bypass line and a supply line. On the other hand, the liquefied natural gas that has not been vaporized is supplied to a forced vaporizer through a gas-liquid separator, and is forcibly vaporized and then supplied to a gas engine through a supply line. As described above, the present inventors have focused on the fact that the gas evaporated by the heat exchanger can be effectively used by the gas engine. Thus, energy efficiency can be improved without wasting the gas itself vaporized by the heat exchanger and the energy used for the vaporization. Further, the gas vaporized by the heat exchanger is not supplied to the forced vaporizer, and the amount of heat used in the forced vaporizer can be suppressed.

  The ship according to the second aspect further includes a return line branched from the supply line and connected to the tank, and the heat exchanger includes a liquefied natural gas flowing through the liquid supply line and a vaporized gas flowing through the return line. Heat exchange may be performed between them.

  According to the structure of the ship which concerns on this 2nd aspect, the vaporization gas which flows into a return line is used for the heating medium for vaporizing the liquefied natural gas which flows into a liquid supply line in a heat exchanger. Thus, the heat of the vaporized gas flowing in the return line can be used as a heating source for the liquefied natural gas flowing in the liquid supply line, and a heating source such as steam can be saved. The vaporized gas flowing in the return line is cooled by the liquefied natural gas flowing in the liquid supply line. Thereby, it is not necessary to separately prepare a heat exchanger for cooling the vaporized gas flowing in the return line and this cooling medium, and the cost of the ship can be reduced.

  In the ship according to the third aspect, the gas engine is a sub-gas engine for power generation, the supply line is a first supply line, and compresses the main gas engine for propulsion and the boil-off gas generated in the tank An air supply line that leads to the compressor, a second supply line that leads the boil-off gas discharged from the compressor to the main gas engine, and an expansion device that branches from the second supply line and leads to the tank A return line, and the heat exchanger may perform heat exchange between the liquefied natural gas flowing through the liquid supply line and the boil-off gas flowing through the return line branched from the second supply line.

  According to the structure of the ship concerning this 3rd aspect, boil-off gas which flows into the return line branched from the 2nd supply line is used for the heating medium for vaporizing the liquefied natural gas which flows into the liquid supply line in a heat exchanger. Yes. Thereby, the boil-off gas flowing through the return line can be used as a heating source for the liquefied natural gas flowing through the liquid feeding line, and a heating source such as steam can be saved. Further, the boil-off gas flowing in the return line is cooled by the liquefied natural gas flowing in the liquid supply line. Thereby, it is not necessary to separately prepare a heat exchanger for cooling the boil-off gas flowing in the return line and this cooling medium, and the cost of the ship can be reduced.

  The ship which concerns on a 4th aspect WHEREIN: The said gas-liquid separator is a 1st gas-liquid separator, and while being provided with the cooler in the said supply line, it is 2nd in the downstream from the said cooler. A gas-liquid separator may be provided. According to the structure of the ship concerning this 4th aspect, heavy components, such as ethane, are removed from vaporization gas by the effect | action of a cooler and a 2nd gas-liquid separator. For this reason, vaporized gas can be supplied not only to gas engines where the vaporized gas used is not limited by methane number but also to gas engines that require vaporized gas with a high methane number. Can respond.

  In the ship according to the fifth aspect, the downstream end of the bypass line may be connected to the supply line between the forced vaporizer and the cooler. According to the structure of the ship which concerns on this 5th aspect, when all the liquefied natural gas is vaporized with a heat exchanger, vaporized gas contains a heavy part. However, by supplying the vaporized gas to the cooler through the bypass line, heavy components such as ethane are cooled and liquefied from the vaporized gas. Therefore, by separating this heavy component with the second gas-liquid separator, not only the gas engine in which the vaporized gas to be used is not limited by the methane number but also the gas engine that requires a vaporized gas having a high methane number. However, vaporized gas can be supplied, and it can respond to a wide range of gas engines.

  In the ship which concerns on a 6th aspect, the downstream end of the said bypass line may be connected to the said supply line in the downstream rather than the said 2nd gas-liquid separator. According to the structure of the ship concerning this 6th aspect, when the vaporized gas which is not contained in a heavy part is produced | generated with the heat exchanger, vaporized gas passes through a bypass line and is not supplied to a cooler. As a result, the vaporized gas is not cooled by the cooler, the flow rate of LNG supplied to the cooler can be reduced, and a decrease in energy efficiency can be suppressed.

  In the ship according to the seventh aspect, the liquid supply line is a first liquid supply line, the first thermometer that detects the temperature of the vaporized gas at the outlet of the cooler, and the upstream side of the heat exchanger, A second liquid feed line branched from the first liquid feed line and connected to the cooler; an adjustment valve provided in the second liquid feed line capable of changing an opening; and a control device for controlling the adjustment valve; The control device may change the opening degree of the regulating valve so that the temperature of the vaporized gas detected by the first thermometer becomes a predetermined temperature.

  According to the configuration of the ship according to the seventh aspect, the flow rate of the liquefied natural gas supplied to the cooler through the second liquid feeding line is adjusted according to the amount of heat given from the heating medium to the liquefied natural gas in the heat exchanger. By adjusting with the valve, the vaporized gas is maintained at a predetermined temperature at the outlet of the cooler, and the vaporized gas from which heavy components have been appropriately removed by the second gas-liquid separator can be supplied to the secondary gas engine. it can.

  A ship according to an eighth aspect includes a first flow meter that detects a flow rate of liquefied natural gas flowing in the first liquid feed line between a branch point of the second liquid feed line and the heat exchanger, A second flow meter for detecting a flow rate of the liquefied natural gas flowing in the first liquid feed line downstream from the one gas-liquid separator, and the control device is detected by the first flow meter. You may adjust the speed | rate which changes the opening degree of the said adjustment valve according to the flow volume of liquefied natural gas, and the flow volume of the liquefied natural gas detected by the said 2nd flow meter. According to the configuration of the ship according to the eighth aspect, by adjusting the flow rate change rate of the liquefied natural gas based on the detection values by the first flow meter and the second flow meter, the followability to the change in the outlet temperature of the cooler is achieved. Can be improved.

  The ship according to a ninth aspect further includes a second thermometer that detects a temperature of the liquefied natural gas flowing in the first liquid feeding line at a downstream side of the first gas-liquid separator, and the control device includes: The flow rate of the liquefied natural gas detected by the first flow meter, the flow rate of the liquefied natural gas detected by the second flow meter, and the temperature of the liquefied natural gas detected by the second thermometer You may adjust the speed which changes the opening degree of an adjustment valve. According to the configuration of the ship according to the ninth aspect, by adjusting the flow rate change rate of the liquefied natural gas based on the detected values by the first flow meter, the second flow meter, and the second thermometer, the outlet of the cooler The followability to a temperature change can be improved.

  The present invention has an effect that it can provide a ship having the above-described configuration and improved energy efficiency.

1 is a schematic configuration diagram of a ship according to a first embodiment of the present invention. It is a schematic block diagram of the ship which concerns on the 1st modification of 1st Embodiment of this invention. It is a schematic block diagram of the ship which concerns on the 2nd modification of 1st Embodiment of this invention. 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 other embodiment of this invention.

(First embodiment)
FIG. 1 shows a ship 1A according to the first embodiment of the present invention. This ship 1 </ b> A includes a tank 10 that stores liquefied natural gas (hereinafter referred to as LNG), a main gas engine 20, and a secondary gas engine 30. The main gas engine 20 is a gas engine for propulsion, and the auxiliary gas engine 30 is a gas engine for power generation (that is, for inboard power).

  In the illustrated example, only one tank 10 is provided, but a plurality of tanks 10 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 10 shown in FIG. 1 is each of a plurality of cargo tanks. In the illustrated example, one main gas engine 20 and one sub gas engine 30 are provided, but a plurality of main gas engines 20 may be provided, or a plurality of sub gas engines 30 may be provided. Good.

  In the present embodiment, the ship 1A is a mechanical propulsion type, and the main gas engine 20 directly rotates and drives a screw propeller (not shown). However, the ship 1A may be an electric propulsion type, and the main gas engine 20 may rotationally drive the screw propeller via a generator and a motor.

  The main gas engine 20 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 20 may be an Otto cycle type two-stroke engine having an intermediate 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 20 may be an Otto cycle type four-stroke engine with a low fuel gas injection pressure of about 0.5 to 1 MPa, for example. The main gas engine 20 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 30 is an Otto cycle type four-stroke engine having a low fuel gas injection pressure of, for example, about 0.5 to 1 MPa, and is connected to a generator (not shown). The auxiliary gas engine 30 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 20 is mainly boil-off gas (hereinafter referred to as BOG) obtained by vaporizing LNG in the tank 10 due to natural heat input. The fuel gas of the auxiliary gas engine 30 is mainly a vaporized gas (hereinafter referred to as VG) in which LNG is forcibly vaporized.

  Specifically, a pump 11 is disposed in the tank 10, and the pump 11 is connected to a forced vaporizer 32 by a first liquid feed line 31, and the forced vaporizer 32 is a first supply line 33. To the auxiliary gas engine 30. The tank 10 is connected to a compressor 22 through an air supply line 21, and the compressor 22 is connected to the main gas engine 20 through a second supply line 23.

  The first liquid feeding line 31 guides LNG discharged from the pump 11 to the forced vaporizer 32. The forced vaporizer 32 forcibly vaporizes LNG using, for example, steam generated in a boiler as a heating source, and generates VG. The first supply line 33 guides the VG generated by the forced vaporizer 32 to the auxiliary gas engine 30.

  The first liquid feed line 31 is provided with a heat exchanger 34A, and a first gas-liquid separator 35 is provided on the downstream side of the heat exchanger 34A. A second liquid supply line 36 and a bypass line 37A are connected to the first liquid supply line 31. The first supply line 33 is provided with a cooler 41, a second gas-liquid separator 42, and a heater 43 in order from the upstream side. A first return line 45 is connected to the first supply line 33.

  The heat exchanger 34A vaporizes LNG by exchanging heat between the LNG flowing through the first liquid feeding line 31 and the heating medium. In this embodiment, the heat exchanger 34A performs heat exchange between the LNG flowing through the first liquid feeding line 31 and the BOG flowing through the second return line 24 described later. When the amount of heat given from the heating medium to LNG is less than the amount of heat that vaporizes LNG, LNG is not vaporized by heat exchanger 34A.

  Furthermore, the heat exchanger 34 </ b> A is provided in the air supply line 21 in addition to the first liquid supply line 31 and the second return line 24. For this reason, the heat exchanger 34 </ b> A also performs heat exchange between the BOG flowing in the air supply line 21 and the BOG flowing in the second return line 24 on the upstream side of the expansion device 25. Thus, in the heat exchanger 34A, the high-pressure and high-temperature BOG flowing through the second return line 24 is cooled by the low-temperature LNG flowing through the first liquid-feed line 31 and the low-pressure and low-temperature BOG flowing through the air-feed line 21. The The surplus BOG is expanded and liquefied by the expansion device 25 and returned to the tank 10. In this embodiment, the LNG flowing through the first liquid supply line 31 and the BOG flowing through the second return line 24 exchange heat, and the BOG flowing through the air supply line 21 flows through the second return line 24. A heat exchanger for exchanging heat with the BOG is integrally provided. However, these heat exchangers may be provided separately.

  The first gas-liquid separator 35 separates the LNG flowing from the heat exchanger 34A into a liquid component LNG and a gas component VG vaporized by the LNG. The first gas-liquid separator 35 is connected to the upstream end of the bypass line 37A. The downstream end of the bypass line 37 </ b> A is connected to the first supply line 33 so that the bypass line 37 </ b> A bypasses the forced vaporizer 32. In this embodiment, the downstream end of the bypass line 37 </ b> A is connected to the first supply line 33 between the forced vaporizer 32 and the cooler 41. In other words, the cooler 41 is located downstream of the connection point of the downstream end of the bypass line 37 </ b> A in the first supply line 33. The VG separated by the first gas-liquid separator 35 flows through the bypass line 37A.

  The forced vaporizer 32 forcibly vaporizes the liquid component separated by the first gas-liquid separator 35, that is, LNG that has not been vaporized by the heat exchanger 34A, and generates VG. The VG generated by the forced vaporizer 32 merges with the VG flowing from the bypass line 37A and then flows into the cooler 41.

  The second liquid feeding line 36 branches from the first liquid feeding line 31 on the upstream side of the heat exchanger 34A and is connected to the cooler 41. The low-temperature LNG before being heated by the BOG in the heat exchanger 34A flows into the second liquid feeding line 36 from the first liquid feeding line 31, flows into the second liquid feeding line 36, and is supplied to the cooler 41. .

  The cooler 41 cools the VG vaporized by the forced vaporizer 32 and / or the VG vaporized by the heat exchanger 34A. The cooler 41 is, for example, a spray type cooler provided with a spray nozzle. In the cooler 41, the low-temperature LNG supplied through the second liquid feeding line 36 is sprayed from the spray nozzle, whereby the VG flowing from the forced vaporizer 32 and the bypass line 37A is cooled. At this time, for example, VG is cooled to −140 to −100 ° C., and generates a liquid component mainly composed of components other than methane. Thereby, heavy components such as ethane are removed from VG, and the methane number of VG is increased. The cooler 41 is not limited to a spray cooler.

  The second gas-liquid separator 42 collects the liquid component generated by the cooler 41. The collected liquid component is returned to the tank 10 through the drain line 46. On the other hand, VG passes through the second gas-liquid separator 42 and is heated by the heater 43. As a result, VG having an appropriate temperature can be supplied to the auxiliary gas engine 30.

  The first return line 45 branches from the first supply line 33 and is connected to the tank 10. In this embodiment, this branch point is located between the second gas-liquid separator 42 and the heater 43. The tip of the first return line 45 may be located in the gas phase of the tank 10 or may be located in the liquid phase. Depending on the load of the auxiliary gas engine 30, the amount of VG used in the auxiliary gas engine 30 may be smaller than the amount of VG vaporized by the heat exchanger 34A and the forced vaporizer 32. The first return line 45 is a line for returning such surplus VG (the difference between the VG generation amount and the VG usage amount) to the tank 10.

  The air supply line 21 guides BOG generated in the tank 10 to the compressor 22. In the present embodiment, the compressor 22 is a multistage high-pressure compressor. The compressor 22 compresses the BOG to a high pressure. The second supply line 23 guides high-pressure BOG discharged from the compressor 22 to the main gas engine 20. However, the compressor 22 may be a low-pressure compressor when the fuel gas injection pressure of the main gas engine 20 is low, for example.

  A second return line 24 is branched from the second supply line 23 on the downstream side of the compressor 22. The second return line 24 is connected to the tank 10. The tip of the second return line 24 may be located in the gas phase of the tank 10 or in the liquid phase. The second return line 24 is provided with an expansion device 25 (for example, a Joule Thomson valve, an expansion turbine, an ejector, etc.).

  Depending on the load of the main gas engine 20, the amount of BOG used in the main gas engine 20 may be smaller than the amount of BOG generated in the tank 10. The second return line 24 is a line for returning such surplus BOG to the tank 10.

  In the first liquid supply line 31, the second liquid supply line 36, the first return line 45, and the second return line 24, the first adjustment valve 31a, the second adjustment valve 36a, and the third adjustment valve that can be changed in opening degree are provided. 45a and a fourth regulating valve 24a are provided. The second return line 24 is provided with an opening / closing valve 24b, and the opening / closing valve 24b opens and closes the second return line 24. These control valves 31a, 36a, 45a, 24a and the on-off valve 24b are controlled by the control device 2. In FIG. 1, only some signal lines are drawn for the sake of simplicity. In this embodiment, the on-off valve 24 b is provided in the second return line 24. However, an opening / closing valve may be provided in a line other than the second return line 24, or the opening / closing valve 24b may not be provided in the second return line 24.

  As described above, in the ship 1A of the present embodiment, LNG is vaporized by the heat exchanger 34A, and the vaporized VG is separated by the first gas-liquid separator 35. Thereby, the calorie | heat amount used for the forced vaporization in the forced vaporizer 32 can be suppressed.

  Further, the bypass line 37 </ b> A is connected to the first gas-liquid separator 35 and the first supply line 33. Thus, the VG vaporized by the heat exchanger 34A is supplied to the auxiliary gas engine 30 via the first gas-liquid separator 35 and the bypass line 37A and the first supply line 33. For this reason, VG flowing from the heat exchanger 34A is effectively used in the auxiliary gas engine 30, and energy efficiency is improved.

  Further, when all of the LNG is vaporized in the heat exchanger 34A, the VG includes a heavy component. However, the bypass line 37 </ b> A is connected to the first gas-liquid separator 35 and the first supply line 33. Thereby, since VG is supplied to the cooler 41 by the bypass line 37A, the heavy component in VG is cooled and liquefied here. Therefore, this heavy component is separated by the second gas-liquid separator 42. For this reason, not only the subgas engine 30 in which the VG to be used is not limited by the methane number but also the subgas engine 30 that requires a vaporized gas having a high methane number, the vaporized gas can be supplied widely. This can correspond to the auxiliary gas engine 30.

  In addition, BOG flowing in the second return line 24 is used as a heating medium for vaporizing LNG flowing in the first liquid supply line 31 in the heat exchanger 34A. Thereby, the heat of this BOG can be utilized as a heating source of LNG, and heating sources, such as a vapor | steam, can be saved. On the other hand, the BOG flowing through the second return line 24 is cooled by the LNG flowing through the first liquid supply line 31. Thereby, it is not necessary to prepare the heat exchanger for cooling BOG and this cooling medium separately, and cost reduction of ship 1A is achieved.

(First modification)
A ship 1A according to a first modification of the first embodiment further includes a first thermometer 47 as shown in FIG. The first thermometer 47 detects the temperature of the VG at the outlet of the cooler 41. The first thermometer 47 may be provided in the first supply line 33 at the outlet of the cooler 41 or at the downstream side of the cooler 41 as long as the temperature of the VG at the outlet of the cooler 41 can be detected.

  The control device 2 changes the opening degree of the second adjustment valve 36a so that the temperature detected by the first thermometer 47 becomes a predetermined temperature. That is, for the secondary gas engine 30 requiring VG having a high methane number, the heavy component must be cooled and liquefied by the cooler 41 to be removed. For this reason, the flow rate of LNG supplied to the cooler 41 is adjusted by the second regulating valve 36a so that the temperature of the VG at the outlet of the cooler 41 becomes a predetermined temperature that can sufficiently liquefy the heavy component in the VG. There is a need to.

  Therefore, the control device 2 obtains the temperature of the VG at the outlet of the cooler 41 from the detection value signal based on the first thermometer 47, and adjusts the second adjustment valve 36a according to the difference between this temperature and the predetermined temperature. . As a result, LNG having a flow rate corresponding to the opening degree is supplied to the cooler 41, and the VG can be maintained at a predetermined temperature at the outlet of the cooler 41.

  For example, if the amount of heat given to the LNG when it is vaporized from LNG to VG in the heat exchanger 34A is large, the flow rate of LNG vaporized in the heat exchanger 34A increases. For this reason, LNG vaporized by the forced vaporizer 32 decreases, and the temperature of the VG generated by the forced vaporizer 32 increases. Along with this, the temperature of the VG flowing into the cooler 41, and consequently, the temperature of the VG at the outlet of the cooler 41 increases. As described above, when a difference between the VG temperature detected by the first thermometer 47 and the predetermined temperature occurs, the opening degree of the second regulating valve 36a increases, and the LNG supplied to the cooler 41 increases. . Therefore, the VG is sufficiently cooled to a predetermined temperature in the cooler 41, and the VG from which the heavy components are removed by the second gas-liquid separator 42 is supplied to the auxiliary gas engine 30 that requires vaporized gas having a high methane number. be able to.

(Second modification)
As shown in FIG. 3, the ship 1A according to the second modification of the first embodiment further includes a first flow meter 38, a second flow meter 39, and a second thermometer 40 in addition to the first thermometer 47. I have.
The first flow meter 38 detects the flow rate of LNG flowing in the first liquid feed line 31 between the branch point of the second liquid feed line 36 and the heat exchanger 34A. The first flow meter 38 detects the total flow rate of LNG supplied from the tank 10 to the heat exchanger 34A through the first liquid feeding line 31. Further, the second flow meter 39 detects the flow rate of LNG flowing in the first liquid feeding line 31 on the downstream side of the first gas-liquid separator 35. The second flow meter 39 detects the flow rate of the LNG remaining after the VG is separated by the first gas-liquid separator 35 and supplied to the forced vaporizer 32. Further, the second thermometer 40 detects the temperature of LNG flowing through the first liquid feeding line 31 on the downstream side of the first gas-liquid separator 35. The second thermometer 40 detects the temperature of the LNG remaining after the VG is separated by the first gas-liquid separator 35 and supplied to the forced vaporizer 32. In addition, the 1st flow meter 38, the 2nd flow meter 39, and the 2nd thermometer 40 are not limited to the position shown in figure.

  The control device 2 changes the opening degree of the second adjustment valve 36a so that the temperature of the VG at the outlet of the cooler 41 detected by the first thermometer 47 becomes a predetermined temperature. Further, in order to improve temperature followability, the control device 2 detects the LNG flow rate detected by the first flow meter 38, the LNG flow rate detected by the second flow meter 39, and the second thermometer 40. The speed at which the opening of the second adjustment valve 36a is changed is adjusted according to the temperature of the LNG.

  In the adjustment of the change rate of the opening degree of the second adjustment valve 36a, specifically, the control device 2 obtains the total flow rate Ft of LNG supplied to the heat exchanger 34A from the detection value of the first flow meter 38. . Further, from the detection value of the second flow meter 39, the flow rate Fl of LNG supplied to the forced vaporizer 32 without being vaporized by the heat exchanger 34A is obtained. Further, the temperature Tl of LNG supplied to the forced vaporizer 32 is obtained from the detected value of the second thermometer 40.

  Based on the difference ΔF between the total LNG flow rate Ft and the flow rate Fl, the VG flow rate Fg1 vaporized in the heat exchanger 34A is obtained. Here, when a part of LNG is vaporized into VG in the heat exchanger 34A, the temperature Tg1 of this VG becomes the saturation temperature of LNG. Therefore, when 0 <ΔF <Ft, that is, when a part of LNG is vaporized in the heat exchanger 34A, the saturation temperature of LNG is obtained as the temperature Tg1 of VG.

  Subsequently, the flow rate Fg2 and the temperature Tg2 of VG vaporized by being heated by the forced vaporizer 32 are obtained from the flow rate Fl and the temperature Tl of LNG. The relationship between the LNG flow rate Fl and temperature Tl and the VG flow rate Fg2 and temperature Tg2 is obtained in advance through experiments and calculations. For example, the greater the LNG flow rate Fl, the greater the VG flow rate Fg2 and the lower the VG temperature Tg2.

  Based on the flow rate Fg1 and temperature Tg1 of VG vaporized by the heat exchanger 34A and the flow rate Fg2 and temperature Tg2 of VG vaporized by the forced vaporizer 32, the flow rate Fg of VG supplied to the cooler 41 and A temperature Tg is obtained. The relationship between the flow rates Fg1 and Fg2 and the temperatures Tg1 and Tg2 and the VG flow rate Fg and the temperature Tg is obtained in advance through experiments and calculations.

  And the control apparatus 2 adjusts the change speed of the opening degree of the 2nd adjustment valve 36a according to the flow volume Fg and temperature Tg of VG supplied to the cooler 41. FIG. For example, the larger the VG flow rate Fg and the higher the VG temperature Tg, the greater the rate of change of the opening of the second regulating valve 36a, and the LNG supplied from the second liquid feed line 36 to the cooler 41. Increase the rate of change of flow rate. Thereby, when the calorie | heat amount of VG which flows into the cooler 41 is large, VG can be rapidly cooled by LNG. On the other hand, the smaller the VG flow rate Fg and the lower the VG temperature Tg, the smaller the rate of change of the opening of the second regulating valve 36a and the LNG supplied from the second liquid feed line 36 to the cooler 41. Reduce the rate of change of the flow rate. Thereby, when the calorie | heat amount of VG which flows into the cooler 41 is small, it can prevent that LNG is supplied to the cooler 41 excessively, and problems, such as an overshoot, can be suppressed.

  In the second modification, the speed at which the opening of the second adjustment valve 36a is changed is adjusted based on the detected values of the first flow meter 38, the second flow meter 39, and the second thermometer 40. On the other hand, the speed at which the opening degree of the second adjustment valve 36a is changed may be adjusted based on the detected values of the first flow meter 38 and the second flow meter 39. In this case, the control device 2 obtains the total flow rate Ft of LNG based on the detection value of the first flow meter 38 and the flow rate Fl of LNG based on the detection value of the second flow meter 39. In accordance with the flow rate Fg of VG obtained from the flow rate Fg1 of VG based on the difference ΔF and the flow rate Fg2 of VG based on the flow rate Fl of LNG, the control device 2 changes the opening change rate of the second adjustment valve 36a. adjust. For example, as the flow rate Fg of VG increases, the change rate of the opening degree of the second adjustment valve 36a is increased. Thereby, the temperature followability with respect to the temperature at the outlet of the cooler 41 is improved.

(Second Embodiment)
Next, with reference to FIG. 4, the ship 1B which concerns on 2nd Embodiment of this invention is demonstrated. In the present embodiment and all the embodiments described later, the same components as those in the first embodiment are denoted by the same reference numerals, and redundant description is omitted.

  In the first embodiment, the downstream end of the bypass line 37A is connected to the first supply line 33 between the forced vaporizer 32 and the cooler 41, whereas in the second embodiment, the downstream end of the bypass line 37B. The end is connected to the first supply line 33 on the downstream side of the second gas-liquid separator 42. In the first embodiment, the cooler 41 cools the VG vaporized by the forced vaporizer 32 and the VG vaporized by the heat exchanger 34A, whereas in the second embodiment, the cooler 41 is forced vaporized. Only the VG vaporized in the vessel 32 is cooled. Furthermore, in 1st Embodiment, the control apparatus 2 adjusts the change rate of the opening degree of the 2nd adjustment valve 36a based on each detection value of the 1st flow meter 38, the 2nd flow meter 39, and the 2nd thermometer 40. On the other hand, in 2nd Embodiment, the control apparatus 2 adjusts the change rate of the opening degree of the 2nd adjustment valve 36a based on each detection value of the 2nd flow meter 39 and the 2nd thermometer 40. FIG.

  Specifically, the bypass line 37B bypasses the forced vaporizer 32, the cooler 41, and the second gas-liquid separator 42. The downstream end of the bypass line 37B is connected to the first supply line 33 between the second gas-liquid separator 42 and the heater 43 in the downstream side of the second gas-liquid separator 42, in this embodiment. . The bypass line 37 </ b> B guides the VG that has been vaporized by the heat exchanger 34 </ b> A and then separated by the first gas-liquid separator 35 to the heater 43. For example, when a VG that does not contain a heavy component is generated from LNG by vaporization in the heat exchanger 34A, the VG is not supplied to the cooler 41 because the VG does not require cooling and removal of a heavy component. The VG that does not include a heavy component means not only a VG that does not include any heavy component, but also a VG that does not include a heavy component that is larger than the allowable amount of the auxiliary gas engine 30.

  The cooler 41 cools the VG vaporized by the forced vaporizer 32. For example, in the cooler 41, the low-temperature LNG supplied through the second liquid feeding line 36 is sprayed from the spray nozzle, whereby the VG flowing from the forced vaporizer 32 is cooled. Thereby, for example, heavy components other than methane are liquefied. This liquid component is collected by the second gas-liquid separator 42 to remove heavy components from VG. This VG passes through the second gas-liquid separator 42 and is supplied to the heater 43.

  In the heater 43, the VG vaporized by the heat exchanger 34A and the VG vaporized by the forced vaporizer 32 are heated. The VG heated to the proper temperature of the auxiliary gas engine 30 by the heater 43 is supplied to the auxiliary gas engine 30.

  The control device 2 changes the opening degree of the second adjustment valve 36a so that the temperature detected by the first thermometer 47 becomes a predetermined temperature. Furthermore, when improving temperature followability, the control apparatus 2 adjusts the change rate of the opening degree of the 2nd adjustment valve 36a based on each detection value of the 2nd flow meter 39 and the 2nd thermometer 40. .

  Specifically, signals of detection values are transmitted from the second flow meter 39 and the second thermometer 40 to the control device 2. From the detected value of the second flow meter 39, the LNG flow rate Fl is obtained, and from the detected value of the second thermometer 40, the LNG temperature Tl is obtained. Based on the obtained flow rate Fl and temperature Tl of LNG, the flow rate Fg2 and temperature Tg2 of VG heated and vaporized by the forced vaporizer 32 are obtained. This VG flow rate Fg2 and temperature Tg2 become the VG flow rate Fg and temperature Tg supplied to the cooler 41. And the control apparatus 2 adjusts the change speed of the opening degree of the 2nd adjustment valve 36a based on the flow volume Fg and temperature Tg of VG supplied to the cooler 41. FIG.

  As described above, in the marine vessel 1 </ b> B of the present embodiment, the downstream end of the bypass line 37 </ b> B is connected to the first supply line 33 on the downstream side of the second gas-liquid separator 42. For this reason, for example, when VG which does not contain heavy components is generated in the heat exchanger 34A, the VG passes through the bypass line 37B and is not supplied to the cooler 41. Thereby, since this VG is not cooled by the cooler 41, the flow rate of LNG supplied to the cooler 41 can be reduced, and the decrease in energy efficiency can be suppressed.

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

(Third embodiment)
Next, a ship 1C according to a third embodiment of the present invention will be described with reference to FIG. In the first embodiment, the heat exchanger 34A that performs heat exchange between the LNG flowing in the first liquid feeding line 31 and the BOG flowing in the second return line 24 is adopted, whereas in the third embodiment, In addition, a heat exchanger 34B that performs heat exchange between the LNG flowing through the first liquid feeding line 31 and the VG flowing through the first return line 45 is employed. For this reason, the heating medium for heat exchange is VG flowing in the first return line 45.

  Specifically, in the heat exchanger 34B, the LNG flowing through the first liquid supply line 31 is heated by the VG flowing through the first return line 45, and the LNG is vaporized into VG. Thus, the vaporized VG is separated by the first gas-liquid separator 35 and supplied to the cooler 41 through the bypass line 37A. The LNG remaining without being vaporized is vaporized by the forced vaporizer 32 via the first gas-liquid separator 35. When the amount of heat given from VG flowing through the first return line 45 to the LNG is less than the amount of heat that vaporizes the LNG, the LNG is not vaporized by the heat exchanger 34B.

  On the other hand, the heat exchanger 34 </ b> B is provided in the first liquid feeding line 31 and the first return line 45. In the heat exchanger 34B, the VG flowing through the first return line 45 is cooled by the LNG flowing through the first liquid supply line 31, and a part of the VG is liquefied into LNG. Thereby, VG and LNG are returned to the tank 10.

  As described above, VG flowing in the first return line 45 is used as a heating medium for vaporizing LNG flowing in the first liquid supply line 31 in the heat exchanger 34B. Thereby, the heat of VG can be used as a heating source of LNG, and a heating source such as steam can be saved. On the other hand, the VG flowing through the first return line 45 is cooled by the LNG flowing through the first liquid supply line 31. Thereby, it is not necessary to prepare the heat exchanger for cooling this VG and this cooling medium separately, and cost reduction of the ship 1C is achieved. Also in this embodiment, the same effect as that of the first embodiment can be obtained.

(Fourth embodiment)
Next, with reference to FIG. 6, the ship 1D which concerns on 4th Embodiment of this invention is demonstrated. In the second embodiment, the heat exchanger 34A that performs heat exchange between the LNG flowing in the first liquid feeding line 31 and the BOG flowing in the second return line 24 is adopted, whereas in the fourth embodiment, In addition, a heat exchanger 34B that performs heat exchange between the LNG flowing through the first liquid feeding line 31 and the VG flowing through the first return line 45 is employed.

  Specifically, in the heat exchanger 34B, the LNG flowing through the first liquid supply line 31 is heated by the VG flowing through the first return line 45, and the LNG is vaporized into VG. Thus, the vaporized VG is separated by the first gas-liquid separator 35 and supplied to the heater 43 through the bypass line 37B. The LNG remaining without being vaporized is vaporized by the forced vaporizer 32 via the first gas-liquid separator 35.

  On the other hand, the heat exchanger 34 </ b> B is provided in the first liquid feed line 31 and the first return line 45. In the heat exchanger 34B, the VG flowing through the first return line 45 is cooled by the LNG flowing through the first liquid supply line 31, and a part of the VG is liquefied into LNG. Thereby, VG and LNG are returned to the tank 10.

  As described above, VG flowing in the first return line 45 is used as a heating medium for vaporizing LNG flowing in the first liquid supply line 31 in the heat exchanger 34B. Thereby, the heat of VG can be used as a heating source of LNG, and a heating source such as steam can be saved. On the other hand, the VG flowing through the first return line 45 is cooled by the LNG flowing through the first liquid supply line 31. Thereby, it is not necessary to prepare the heat exchanger for cooling this VG and this cooling medium separately, and cost reduction of ship 1D is achieved. Also in this embodiment, the same effect as in the second embodiment can be obtained.

(Other embodiments)
The present invention is not limited to the first to fourth embodiments described above, and various modifications can be made without departing from the gist of the present invention. For example, as shown in FIG. 7, the ship 1E includes a second liquid feeding line 36, a cooler 41, a second gas-liquid separator 42, a heater 43, a main gas engine 20 (or a sub-gas engine 30), and a compressor. 22, the air supply line 21 and the second return line 24 may not be provided. That is, the ship 1E includes the tank 10, the pump 11, the gas engine 130, the liquid supply line 31, the heat exchanger 134, the supply line 133, the forced vaporizer 32, the first gas-liquid separator 35, and the bypass line 137. That's fine. The gas engine 130 is the auxiliary gas engine 30 or the main gas engine 20. The liquid feed line 31 guides the liquefied natural gas discharged from the pump 11 disposed in the tank 10 to the forced vaporizer 32. The heat exchanger 134 performs heat exchange between the liquefied natural gas flowing in the liquid feeding line 31 and the heating medium. The supply line 133 guides the vaporized gas generated by the forced vaporizer 32 to the gas engine 130. The first gas-liquid separator 35 is provided in the liquid feeding line 31 on the downstream side of the heat exchanger 134. The bypass line 137 has an upstream end connected to the first gas-liquid separator 35, a downstream end connected to the supply line 133, and VG separated by the first gas-liquid separator 35 flows.

Furthermore, in each embodiment, a heat exchanger in which the heat exchanger 34B and the heat exchanger 34A are integrally combined may be used. Further, one or both of the main gas engine 20 and the auxiliary gas engine 30 are not necessarily a reciprocating engine, and may be a gas turbine engine.
Further, the air supply line 21 and the second supply line 23 may be omitted, and the VG may be supplied not only to the auxiliary gas engine 30 but also to the main gas engine 20 through the first supply line 33.

  In the first embodiment and the third embodiment, the first flow meter 38 is downstream of the branch point of the second liquid feed line 36 between the branch point of the second liquid feed line 36 and the heat exchanger 34A. On the side, the flow rate of LNG flowing through the first liquid feeding line 31 was detected. On the other hand, the first flow meter 38 may detect the flow rate of LNG flowing through the first liquid supply line 31 on the upstream side of the branch point of the second liquid supply line 36. In this case, the control device 2 determines the first flow rate based on the flow rate of LNG detected by the first flow meter 38 and the flow rate of LNG flowing in the second liquid supply line 36 obtained from the opening degree of the second adjustment valve 36a. You may obtain | require the flow volume of LNG which flows into the 1st liquid feeding line 31 in the downstream rather than the branch point of the 2 liquid feeding lines 36. FIG.

  In the first and second embodiments, the first return line 45 may not be provided. Furthermore, in the third and fourth embodiments, the second return line 24 may not be provided.

  In the third and fourth embodiments, in the heat exchanger 34B, VG that flows in the first return line 45 is used as the heating medium that exchanges heat with LNG that flows in the first liquid feeding line 31, but the heating medium Is not limited to this. For example, cooling water that cools the engine may be used as the heating medium. Further, the ships 1C and 1D of the third and fourth embodiments include the main gas engine 20 and an air supply line 21 connected thereto, but the ships 1C and 1D of the third and fourth embodiments are the same. These may not be provided.

1A: Vessel 1B: Vessel 1C: Vessel 1D: Vessel 1E: Vessel 2: Control device 10: Tank 11: Pump 20: Main gas engine (gas engine)
21: Air supply line 23: Second supply line 24: Second return line (return line)
30: Sub-gas engine (gas engine)
31: 1st liquid feeding line (liquid feeding line)
32: Forced vaporizer 33: First supply line (supply line)
34A: Heat exchanger 34B: Heat exchanger 35: First gas-liquid separator (gas-liquid separator)
36: Second liquid feeding line 36a: Second regulating valve (regulating valve)
37A: Bypass line 37B: Bypass line 38: First flow meter 39: Second flow meter 40: Second thermometer 41: Cooler 42: Second gas-liquid separator 45: First return line (return line)
130: Gas engine 133: Supply line 134: Heat exchanger 137: Bypass line

Claims (9)

A gas engine,
A tank for storing liquefied natural gas;
A liquid feed line for guiding liquefied natural gas discharged from a pump disposed in the tank to a forced vaporizer;
A heat exchanger for exchanging heat between the liquefied natural gas flowing in the liquid feed line and the heating medium;
A supply line for guiding the vaporized gas generated in the forced vaporizer to the gas engine;
A gas-liquid separator provided in the liquid feed line downstream of the heat exchanger;
A ship having an upstream end connected to the gas-liquid separator, a downstream end connected to the supply line, and a bypass line through which vaporized gas separated by the gas-liquid separator flows. A return line branched from the supply line and connected to the tank;
The ship according to claim 1, wherein the heat exchanger performs heat exchange between the liquefied natural gas flowing through the liquid feeding line and the vaporized gas flowing through the return line. The gas engine is a secondary gas engine for power generation, and the supply line is a first supply line;
A main gas engine for propulsion,
An air supply line for guiding boil-off gas generated in the tank to the compressor;
A second supply line for guiding boil-off gas discharged from the compressor to the main gas engine;
A return line provided with an expansion device, branched from the second supply line and connected to the tank,
The ship according to claim 1 or 2, wherein the heat exchanger performs heat exchange between the liquefied natural gas flowing in the liquid feeding line and the boil-off gas flowing in a return line branched from the second supply line. The gas-liquid separator is a first gas-liquid separator,
The ship according to any one of claims 1 to 3, wherein a cooler is provided in the supply line, and a second gas-liquid separator is provided downstream of the cooler. .   The ship according to claim 4, wherein a downstream end of the bypass line is connected to the supply line between the forced vaporizer and the cooler.   The ship according to claim 4, wherein a downstream end of the bypass line is connected to the supply line at a downstream side of the second gas-liquid separator. The liquid feeding line is a first liquid feeding line,
A first thermometer for detecting the temperature of the vaporized gas at the outlet of the cooler;
A second liquid feed line branched from the first liquid feed line and connected to the cooler upstream of the heat exchanger;
An adjustment valve provided in the second liquid feeding line and capable of changing an opening;
A control device for controlling the regulating valve,
The ship according to any one of claims 4 to 6, wherein the control device changes the opening degree of the regulating valve so that the temperature of the vaporized gas detected by the first thermometer becomes a predetermined temperature. . A first flow meter for detecting a flow rate of the liquefied natural gas flowing in the first liquid feed line between a branch point of the second liquid feed line and the heat exchanger;
A second flow meter for detecting a flow rate of the liquefied natural gas flowing in the first liquid feed line on the downstream side of the first gas-liquid separator,
The control device has a speed for changing the opening of the regulating valve according to the flow rate of the liquefied natural gas detected by the first flow meter and the flow rate of the liquefied natural gas detected by the second flow meter. The ship according to claim 7, which is adjusted. A second thermometer for detecting the temperature of the liquefied natural gas flowing in the first liquid feeding line on the downstream side of the first gas-liquid separator,
The control device includes a flow rate of the liquefied natural gas detected by the first flow meter, a flow rate of the liquefied natural gas detected by the second flow meter, and a temperature of the liquefied natural gas detected by the second thermometer. The ship of Claim 8 which adjusts the speed which changes the opening degree of the said adjustment valve according to.

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