JP2014104847A - Cold use device for low-temperature liquefied fuel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance thermal efficiency of a combustion engine using low-temperature liquefied fuel as fuel and save energy by enhancing use efficiency of cold that is held by the low-temperature liquefied fuel such as liquefied natural gas.SOLUTION: LNG stored in an LNG tank 12 is supplied to a main combustion engine 10 as LNG gas via a booster pump 22 and a cold recovery heat exchanger 54. A heating medium cooled by the cold recovery heat exchanger 54 is circulated in a re-liquefying device 28 and a cold power generating device 70 and is used as a cold source for the devices. Heat exchange is performed between the heating medium that has been used in the cold power generating device 70 and cooling water circulating in a cooling water closed circuit 60 by a water-cooling heat exchanger 58 to cool the cooling water. The cold power generating device 70 for cooling air supplied to the main combustion engine 10 via a supercharger 30 by using the cooling water by an air-cooling heat exchanger 62 performs cold power generation by using the heating medium as a cold source and exhaust air from the main combustion engine 10 as a heating source.

Description

  The present invention relates to an apparatus that makes it possible to effectively use cold heat held by a low-temperature liquefied fuel when operating a combustion engine that generates power by burning low-temperature liquefied fuel such as liquefied natural gas.

  In recent years, diesel engines and gas engines are effective in reducing emissions (emissions), and therefore, development of a technology that enables the use of liquefied natural gas (LNG) as a fuel is being promoted. Such LNG conversion to fuel tends to spread to relatively large (large output) diesel engines and gas engines, for example, for ship propulsion and generator driving. Further, in a diesel engine or a gas engine, a turbocharger is generally used because it is effective for improving output and reducing emissions (emissions).

  Further, diesel engines and gas engines that use liquefied natural gas as fuel are required to improve efficiency. Since liquefied natural gas has a cryogenic temperature as low as −160 ° C., the efficiency of diesel engines and gas engines can be expected to be improved by effectively using the cold heat of liquefied natural gas.

  Patent Document 1 and Patent Document 2 disclose a cold power generation technique using a temperature difference between both surfaces of a cold insulation layer constituting an LNG storage tank in a tanker that transports liquefied natural gas. In this technology, a low temperature surface is attached to the outer surface of the cold insulation layer that is low in temperature with respect to the outside air, a large number of thermoelectric conversion solid elements are arranged so that the high temperature surface is exposed to the outside air, and the solid elements are connected with each other by lead wires. The current is extracted from the lead wire using the Seebeck effect. Patent Document 3 discloses a technique for cooling combustion air with cold heat of liquefied natural gas in a gas engine using liquefied natural gas as a fuel. That is, a vaporizer that vaporizes liquefied natural gas by a water heating method is provided, and the combustion air supplied to the supercharger is cooled using cooling water cooled by vaporization of the liquefied natural gas as a cold heat source. Thus, the combustion efficiency of the gas engine is improved by increasing the density of the combustion air.

JP 2001-251875 A JP 2002-136161 A JP 2006-177213 A

  The techniques disclosed in Patent Document 1 and Patent Document 2 are still under development, and currently, the thermoelectric conversion efficiency is as low as 5 to 12%. Therefore, it is difficult to efficiently obtain a high voltage. In the technique disclosed in Patent Document 3, the cryogenic liquefied natural gas and the cooling water are directly subjected to heat exchange. However, in this case, the utilization efficiency (exergy efficiency) of the cold heat possessed by the liquefied natural gas is poor. Therefore, it cannot be said that the cold heat possessed by liquefied natural gas is sufficiently utilized, and it remains inefficient use.

  In addition, boil-off gas (BOG) is generated in the gas phase portion in the tank storing LNG. If this is left unattended, the pressure in the gas phase becomes high and dangerous, so it is necessary to reliquefy BOG. In particular, it is necessary to pay attention to this in the case of an LNG tank mounted on a ship that operates for a long time.

  In view of the problems of the prior art, the present invention increases energy efficiency of a combustion engine using low-temperature liquefied fuel as fuel by increasing the utilization efficiency of cold heat held by low-temperature liquefied fuel such as liquefied natural gas. The purpose is to achieve. It is another object of the present invention to prevent high pressure in the gas phase portion in the tank storing the low-temperature liquefied fuel.

  The low-temperature liquefied fuel cold energy utilization device of the present invention includes a low-temperature liquefied fuel tank that stores low-temperature liquefied fuel, a combustion engine that generates power using fuel gas obtained by vaporizing the low-temperature liquefied fuel, and an exhaust from the combustion engine. A turbocharger that is driven by exhaust gas, and a turbocharger that is driven by the turbine and that includes a compressor that sends compressed air to the internal combustion engine, and a low-temperature liquefied fuel supply that supplies high-pressure fuel gas into the cylinder of the combustion engine It is assumed that a booster pump is provided in the system and boosts the temperature of the low-temperature liquefied fuel introduced from the low-temperature liquefied fuel tank.

  In order to achieve the above object, the configuration of the present invention is a heat recovery heat exchange in which a heat medium circulating through a heat medium closed circuit and a high-pressure / low-temperature liquefied fuel pressurized by a booster pump are heat-exchanged to cool the heat medium. And boil-off gas which is provided in a boil-off gas circulation path connected to the gas phase part of the low-temperature liquefied fuel tank and flows through the boil-off gas circulation path using the cold heat of the heat medium cooled by the cold recovery heat exchanger The reliquefaction unit for reliquefying the liquid, the cold heat possessed by the heat medium after being subjected to reliquefaction of the boil-off gas in the reliquefaction unit, and the heat possessed by the combustion engine itself or the exhaust discharged from the combustion engine Cooling power generation unit that performs cold power generation, and supply air or compressor unit of the combustion engine that is introduced into the compressor unit of the supercharger by the cold heat held by the heat medium that has been subjected to reliquefaction of the boil-off gas in the reliquefaction unit In addition Is that and a charge air cooling heat exchanger mechanism for cooling the charge air after.

  In the present invention, the cold heat possessed by the low-temperature liquefied fuel is utilized in three stages of reliquefaction of the boil-off gas, cold power generation, and cooling of the supply air supplied to the combustion engine. The re-liquefaction unit that re-liquefies the boil-off gas is configured by an apparatus such as a refrigerator that can re-liquefy the boil-off gas with the cold heat of the heat medium. Thereby, it is possible to prevent an increase in pressure in the low-temperature liquefied fuel tank without using another cold heat source. Moreover, the electric power generated in the cold power generation unit can be used as a supplement for the output of the combustion engine or as power for another application. Furthermore, the output of the combustion engine can be increased by using the cold heat of the low-temperature liquefied fuel to cool the supply air supplied to the combustion engine. This can increase the thermal efficiency of the combustion engine and achieve energy saving. In cold power generation, power generation efficiency can be improved by using heat stored in the combustion engine itself or in the exhaust of the combustion engine as a heat source.

  The heat medium circulating in the heat medium closed circuit has stable properties at low temperatures and can maintain good fluidity during heat exchange with a low-temperature liquefied fuel having cryogenic heat, such as nitrogen gas. The substance is good. Stable cold power generation can be performed by performing cold heat power generation using cold heat held by a heat medium such as nitrogen without directly performing cold heat power generation with the cold heat held by the low-temperature liquefied fuel. Also, in cooling the supply air, heat is not directly exchanged between the low-temperature liquefied fuel and the supply air, which have a very large temperature difference, but the heat medium such as nitrogen gas cooled by the low-temperature liquefied fuel and the supply air. Exergy efficiency can be improved by making it exchange.

  Low temperature liquefied fuel refers to, for example, liquefied natural gas, liquefied petroleum gas, and the like. The combustion engine is, for example, a propulsion diesel engine or gas engine provided on a ship, or a power generation diesel engine or gas engine provided on land. The diesel engine can be applied regardless of the direct injection method or the premixing method. Further, the present invention can be applied to an LNG carrier having an LNG tank in which cryogenic LNG is stored, a container ship having a combustion engine using LNG as a fuel as a main propulsion engine, and the like.

  In the present invention, the air cooling heat exchanging mechanism includes water that cools the cooling water with a cooling water closed circuit in which the cooling water circulates and a cooling medium possessed by the heat medium after the cooling power generation in the cooling power generation unit. A cooling heat exchanger and an air cooling heat exchanger that uses cooling water cooled by the water cooling heat exchanger and cools air introduced into the compressor section of the supercharger or air pressurized by the compressor section. The cooling water closed circuit is led to the combustion engine, and the high temperature portion of the combustion engine can be cooled by using the cooling water in which the supply air is cooled by the air cooling heat exchanger.

  In this way, the cooling water is cooled by the cold heat held by the heat medium after performing the cold power generation in the cold power generation section, and the cryogenic low-temperature liquefied fuel is not directly exchanged with the cooling water, so the cooling is caused by a very large temperature difference. Water can be prevented from freezing. In addition, a stable cooling effect can be maintained by cooling the supply air supplied to the combustion engine with cooling water having a large specific heat and easy handling, and the high-temperature portion of the combustion engine.

  In the present invention, a supercharger-driven generator driven by the output of the supercharger is provided, and electric power obtained by the supercharger-driven generator is supplied to the reliquefaction unit as auxiliary power, and the turbine of the supercharger It is preferable to perform cold power generation in the cold power generation unit using the retained heat of the exhaust discharged from the unit. Thereby, the output of the supercharger can be effectively used.

  In addition to the above configuration, the exhaust turbine is driven by exhaust discharged from the turbocharger turbine, the reheater reheats the exhaust discharged from the exhaust turbine, and the output shaft of the exhaust turbine. An exhaust turbine-driven generator, supplying electric power obtained by the exhaust turbine-driven generator to the reliquefaction unit as auxiliary power, and using the retained heat of the exhaust discharged from the exhaust turbine, It is good to do. Thereby, the electric power generated by the supercharger-driven generator and the exhaust turbine-driven generator can be supplied to the reliquefaction unit.

  In the present invention, a steam turbine driven by exhaust gas from a combustion engine, and a steam turbine drive generator connected to an output shaft of the steam turbine, and using the retained heat of the exhaust gas discharged from the steam turbine, In this case, cold power generation may be performed. Thereby, the electric power generated by the steam turbine drive generator can be used effectively. For example, when the combustion engine is a main propulsion engine of a ship, the electric power generated by the steam turbine drive generator can be used as necessary electric power for the combustion engine or for utilities such as air conditioning, air conditioning, and hot water supply in the ship.

  In the present invention, the cooling water closed circuit may be led to the cold power generation unit, and the cold heat power generation unit may perform cold power generation using the retained heat of the cooling water after cooling the high-temperature part of the combustion engine. As a result, a large amount of heat possessed by the combustion engine itself can be effectively used for cold power generation with high efficiency.

  In the present invention, there is provided a cooling water circulation path led to a high-temperature part of the compressor unit of the supercharger and the cold power generation unit, and the cold heat power generation unit uses the retained heat of the cooling water after cooling the compressor unit. May be performed. Thereby, the compression heat of the supply air generated in the compressor section of the supercharger can be effectively used for cold power generation.

  In this invention, it is good to provide the thermal storage apparatus in the bypass flow path branched from the heat-medium closed circuit or the heat-medium closed circuit. Thereby, when surplus cold heat is generated in the heat medium circulating in the heat medium closed circuit, the surplus cool heat is temporarily accumulated in the regenerator and can be taken out from the regenerator and used effectively as necessary. For example, it can be used when the temperature of the heat medium rises above the set range, or can be effectively used for other purposes such as driving the reliquefaction heat section. Moreover, since the cold energy which a heat medium has can be adjusted, it can be set as the amount of cold energy which is not over and under operation conditions.

  In addition to the above configuration, the heating medium closed circuit is provided with a heating heat exchanger that recovers excess cooling heat of the heating medium that flows through the heating medium closed circuit, and the heat storage amount of the cold storage device and the heat exchange amount of the heating heat exchanger It is recommended to adjust the amount of cold heat stored in the closed circuit of the heat medium. This makes it easy to adjust the amount of heat held by the heat medium circulating in the heat medium closed circuit, and the surplus can be stored in the cold storage device, so that the amount of cold heat stored in the heat medium can be kept in excess of the demand. Can be adjusted. Moreover, the surplus stored in the cold storage device can be used for other purposes as required.

  In the present invention, the cold power generation unit may be composed of a heat engine that forms a Brayton cycle or a Rankine cycle with good thermal efficiency. In particular, the Brayton cycle is suitable for cold power generation because of its low temperature and excellent thermal efficiency. As a result, the cold heat held by the heat medium circulating in the heat medium closed circuit and the heat held by the combustion engine itself or the exhaust of the combustion engine can be efficiently converted into electric power.

  The cold power generation unit is composed of a heat engine that forms a two-stage Brayton cycle, and the air cooling heat exchange mechanism is a heat medium after performing cold power generation in the cold power generation unit, and is used in the compressor unit of the supercharger. The introduced air or the air after being pressurized by the compressor section may be cooled. By performing cold power generation with a heat engine that forms a two-stage Brayton cycle, the conversion efficiency into electric power is further improved. Further, the supply air can be sufficiently cooled by the heat medium after performing the cold power generation, and conversely the exergy efficiency can be improved.

  According to the present invention, the low-temperature liquefied fuel possessed by using the cold heat possessed by the low-temperature liquefied fuel in three stages of re-liquefaction of boil-off gas, cold power generation, and cooling of the supply air supplied to the combustion engine. It is possible to increase the utilization efficiency of cold heat. As a result, it is possible to achieve energy saving, including improving the thermal efficiency of a combustion engine using low temperature liquefied fuel as fuel.

1 is an overall configuration diagram of a cold energy utilization device according to a first embodiment of the present invention. It is a systematic diagram of the cold power generator which comprises the said cold energy utilization apparatus. It is a diagram which shows the thermal cycle which the said cold / thermal power generation device (1st step) forms. It is a diagram which shows the thermal cycle which the said thermoelectric power generation device (2nd stage) forms. It is a systematic diagram which shows another example of a structure of the said thermal energy generator. It is a whole block diagram of the cold energy utilization apparatus which concerns on 2nd Embodiment of this invention. It is a whole block diagram of the cold energy utilization apparatus which concerns on 3rd Embodiment of this invention. It is a whole block diagram of the cold energy utilization apparatus which concerns on 4th Embodiment of this invention. It is a whole block diagram of the cold energy utilization apparatus which concerns on 5th Embodiment of this invention. It is a whole block diagram of the cold energy utilization apparatus which concerns on 6th Embodiment of this invention. It is a whole block diagram of the cold energy utilization apparatus which concerns on 7th Embodiment of this invention. It is a whole block diagram of the cold energy utilization apparatus which concerns on 8th Embodiment of this invention.

  Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the component parts described in this embodiment are not intended to limit the scope of the present invention to that unless otherwise specified.

(Embodiment 1)
A first embodiment of the present invention will be described with reference to FIG. In addition to the present embodiment, in the embodiments described below, liquefied natural gas (LNG) is used as the low-temperature liquefied fuel, but the low-temperature liquefied fuel is not limited to this, for example, liquefied Petroleum gas (LPG) may be used. The main combustion engine 10 of this embodiment shown in FIG. 1 is a gas engine or a diesel engine, for example. Applications include, for example, a combustion engine in which an output shaft is connected to a propulsion device of a ship and drives the propulsion device, or a combustion engine for power generation that is provided on land and has an output shaft connected to a generator.

  The main combustion engine 10 is a combustion engine that uses high-pressure natural gas (CNG) obtained by increasing and evaporating LNG as fuel and combusting CNG with the supply air pressurized by the supercharger 30 to obtain output. LNG at −160 ° C. is stored in the LNG tank 12. The LNG tank 12 is mounted on a ship when the main combustion engine 10 drives a ship propulsion device, and is provided on the land when the main combustion engine 10 drives a generator on land. A fuel supply system FS is provided to supply LNG stored in the LNG tank 12 as CNG into the cylinder of the main combustion engine 10.

  The fuel supply system FS is provided with a booster pump 22 that boosts the low-pressure LNG sent from the inside of the LNG tank 12 by the submerged pump 14. This booster pump 22 is a pump for boosting the LNG so that the vaporized CNG has a higher pressure than that in the cylinder in order to inject fuel into the cylinder of the main combustion engine 10 that is compressed to a high pressure. is there. The booster pump 22 is a piston pump, for example.

  A suction drum 18 that functions as a buffer is provided on the upstream side of the booster pump 22. The LNG stored in the LNG tank 12 is temporarily stored in the suction drum 18 via the supply path 16. The LNG stored in the suction drum 18 is sent to the booster pump 22 through the supply path 20, and becomes a high pressure LNG by the booster pump 22. The LNG that has become high pressure by the booster pump 22 is sent into the cylinder of the main combustion engine 10 via the supply path 24.

  On the downstream side of the booster pump 22, for example, heating means (not shown) such as an LNG heater is provided as necessary in order to vaporize the high pressure LNG after the pressure increase and convert it to CNG. A cooling heat recovery heat exchanger 54 is provided on the upstream side of the heating means in order to cool the heat medium circulating in the heat medium closed circuit 52 described later with high pressure LNG. The booster pump 22 boosts the low-pressure LNG to a high-pressure LNG in order to reliably supply CNG into the cylinder of the main combustion engine 10 that is compressed and in a high-pressure state. The CNG after vaporizing the high pressure LNG is set to a high pressure that can be injected into the cylinder. CNG injected into the cylinder as fuel needs to be heated to room temperature, but may be 0 ° C. or less, for example, about −50 ° C.

  A BOG circulation path 26 is connected to a gas phase portion formed in the upper part of the LNG tank 12, and a reliquefaction device 28 is provided in the BOG circulation path 26. The BOG circulating in the BOG circulation path 26 is cooled and reliquefied by the reliquefaction device 28 and returned to the LNG tank 12.

  A supercharger 30 is provided in an air supply system that supplies combustion air to the main combustion engine 10. The supercharger 30 includes a turbine 32 that uses exhaust gas discharged from the main combustion engine 10 as a drive source, and a compressor 34 that is coaxially connected to the turbine 32. The supercharger 30 rotates the turbine 32 with the energy of the exhaust of the main combustion engine 10, drives the compressor 34 coaxial with the turbine 32, introduces air in the atmosphere into the air supply system, and compresses it. Thus, the combustion efficiency of the main combustion engine 10 can be improved by increasing the density of the supply air supplied to the main combustion engine 10 and increasing the amount of supply air per unit volume.

  The supercharger 30 includes a supercharger drive generator 36 that is coaxial with the turbine 32 and the compressor 34. Further, an exhaust passage 38 for sending the exhaust of the main combustion engine 10 to the turbine 32, an air supply introduction passage 40 for sending air in the atmosphere to the compressor 34, and compressed air supplied by the compressor 34 are supplied to the main combustion engine 10. A compressed air supply path 42 is provided to the cylinder. The supercharger-driven generator 36 is driven by the output of the supercharger 30 and can obtain electric power with the energy of the exhaust of the main combustion engine 10. This electric power is supplied to the reliquefaction device 28 and can be used as driving auxiliary power for the reliquefaction device 28.

  The cold energy recovery device 50 includes a heat medium closed circuit 52 through which a heat medium such as nitrogen gas flows and a cooling water closed circuit 60 through which cooling water flows. In the heat medium closed circuit 52, heat exchange is performed between the blower 56 that circulates the heat medium closed circuit 52 by feeding nitrogen gas and the high pressure LNG flowing through the supply path 24, and the nitrogen gas is cooled by the high pressure LNG. A cold heat recovery heat exchanger 54 is provided. In this case, the nitrogen gas is used as a heat source that raises the temperature of the high-pressure LNG or a heat source that vaporizes at least a part of the high-pressure LNG.

  As a result, in a heating device such as an LNG heater that vaporizes the high-pressure LNG to form CNG, the amount of heat necessary to vaporize the high-pressure LNG can be reduced. If the nitrogen gas has a sufficient amount of heat, the LNG heater can be eliminated. As a result, power consumption required for the LNG heater can be reduced. Nitrogen gas is heat-exchanged with high-pressure LNG at −160 ° C. and cooled to around −150 ° C.

  The heat medium closed circuit 52 is led to the reliquefaction device 28 on the downstream side of the cold heat recovery heat exchanger 54. The nitrogen gas cooled to about −150 ° C. by the high pressure LNG in the cold heat recovery heat exchanger 54 is used as a cold heat source in the reliquefaction device 28. The reliquefaction device 28 is composed of, for example, a refrigerator, uses the nitrogen gas sent from the heat medium closed circuit 52 as a cold heat source, cools the BOG, and reliquefies it. The liquefied LNG is returned to the LNG tank 12.

  The heat medium closed circuit 52 is further led to the cold heat generator 70 on the downstream side of the reliquefaction device 28. Further, an exhaust passage 44 connected to the exhaust outlet of the turbine 32 of the supercharger 30 is led to the cold heat power generator 70, and the cold heat power generator 70 is used as a cold heat source in the reliquefaction device 28. Cold power generation is performed using the cold heat held by nitrogen gas (-150 ° C to -140 ° C) and the held heat of the exhaust gas (300 to 500 ° C) flowing through the exhaust passage 44.

  A water cooling heat exchanger 58 is provided in the heat medium closed circuit 52 on the downstream side of the cold heat generator 70. A cooling water closed circuit 60 is connected to the water cooling heat exchanger 58, and the cooling water that circulates through the cooling water closed circuit 60 is cooled by the water cooling heat exchanger 58 with the cold heat held by the nitrogen gas. The The cooling water closed circuit 60 is provided with an air cooling heat exchanger 62. The air cooling heat exchanger 62 exchanges heat between the nitrogen gas flowing through the heat medium closed circuit 52 and the supply air flowing from the atmosphere and flowing through the supply air introduction path 40 on the downstream side of the water cooling heat exchanger 58. Cool your mind. The nitrogen gas after the supply air is cooled by the air cooling heat exchanger 62 rises in temperature due to the heat release of the supply air, and then returns to the blower 56 through the heat medium closed circuit 52.

  The supply air cooled by the air cooling heat exchanger 62 has an increased air density and a reduced volumetric flow rate per unit weight. As a result, since the power required to drive the compressor 34 can be reduced in the supercharger 30, the supercharging efficiency of the supercharger 30 can be improved. Moreover, since the generation | occurrence | production of the creep in the member which comprises the supercharger 30 can be suppressed by reducing supply air temperature, the lifetime of the supercharger 30 becomes long. Moreover, since the rotation speed which can be drive | operated can be made high, the performance of the supercharger 30 can be improved. Furthermore, since high-density air supply can be supplied to the main combustion engine 10, the combustion efficiency of the main combustion engine 10 can be improved.

  The cooling water closed circuit 60 is led to a cooling jacket 64 provided at a high temperature portion of the main combustion engine 10 on the downstream side of the air cooling heat exchanger 62. The cooling water closed circuit 60 is provided with a water pump 66, and the water pump 66 circulates cooling water in the direction of the arrow. The high temperature portion of the main combustion engine 10 can be cooled by the cooling water introduced into the cooling jacket 64. The cooling water exiting the cooling jacket 64 is cooled again by nitrogen gas in the water cooling heat exchanger 58.

  Next, the configuration of the cold power generator 70 will be described with reference to FIG. The thermal power generation apparatus may be configured by a component that forms a Brayton cycle or a Rankine cycle that has high thermal efficiency and is capable of thermal power generation as a thermal cycle. The cold power generator 70 is configured by configuring two cold heat generators forming a Brayton cycle in two stages. FIG. 2 shows the first-stage cold-power generator, but the basic structure of the second-stage cool-heat generator is the same as that of the first-stage.

  In FIG. 2, a turbine 702 and a compressor 704 are arranged on both sides of the generator 700, and these are connected by a single output shaft 706. The turbine 702 and the compressor 704 are connected by a refrigerant circulation path 708. In the refrigerant circulation path 708, heat exchangers 710, 712, and 714 are provided. Nitrogen gas is usually used as the refrigerant. Other than nitrogen gas, helium or xenon can be used. In the figure, the arrows attached to each heat exchanger indicate the heat entry / exit direction.

  FIG. 3 is a TS diagram showing a thermal cycle of the first-stage cold power generator. An exhaust passage 44 connected to the exhaust outlet of the turbine 32 of the supercharger 30 is connected to the heat exchanger 710, and 300 to 500 ° C. exhaust is introduced into the heat exchanger 710 from the exhaust passage 44. In the heat exchanger 710, the nitrogen gas is heated to around 300 ° C. by the heat retained in the exhaust (point A → point B in FIG. 3). The nitrogen gas heated by the heat exchanger 710 is sent to the turbine 702, where it adiabatically expands and rotates the output shaft 706 (point B → point C in FIG. 3). As the output shaft 706 rotates, power is generated in the generator 700. The nitrogen gas discharged from the turbine 702 is cooled by heat exchange with the low-temperature nitrogen gas discharged from the compressor 704 in the heat exchanger 712 (isobaric compression; point C → point D in FIG. 3). .

  The nitrogen gas cooled by the heat exchanger 712 is sent to the heat exchanger 714. A heat medium closed circuit 52 is connected to the heat exchanger 714, and the nitrogen gas circulating in the refrigerant circulation path 708 exchanges heat with −150 ° C. to −140 ° C. nitrogen gas circulating in the heat medium closed circuit 52, Cooled to around −140 ° C. (isobaric compression; point D → point E in FIG. 3). The nitrogen gas cooled by the heat exchanger 714 is supplied to the compressor 704 after being used for cooling the generator 700 by the heat exchanger 716. The nitrogen gas is adiabatically compressed by the compressor 704 (point E → point F in FIG. 3). The nitrogen gas discharged from the compressor 704 is heated by exchanging heat with the nitrogen gas discharged from the turbine 702 in the heat exchanger 712 (isobaric expansion; point F → point A in FIG. 3).

  The second-stage cold-power generator (not shown) is composed of the same components as the first-stage cold-power generator, but the specifications and operating conditions of each component are different. FIG. 4 shows the thermal cycle of the second-stage cold power generator. In the first stage of the thermal power generation apparatus, the second stage of the cold power generation is performed using the nitrogen gas at the point F (around −70 ° C.) in FIG. 3, that is, the nitrogen gas after being adiabatically compressed by the compressor 704. It is supplied to the inlet (point E in FIG. 4) of the compressor 704 of the apparatus. Then, after the nitrogen gas is adiabatically compressed by the compressor 704 (point E → point F in FIG. 4), a thermal cycle is formed in the same order as that of the first-stage cold heat generator.

  As a result, electric power can be generated by the generators 700 of both the first-stage cold-power generator and the second-stage cold-power generator. The nitrogen gas after being subjected to the cold power generation in the cold power generator 70 cools the cooling water circulating in the cooling water closed circuit 60 by the water cooling heat exchanger 58. The nitrogen gas supplied to the water cooling heat exchanger 58 has a temperature of 0 ° C. or lower, and maintains a sufficiently low temperature to cool the air in the atmosphere introduced from the supply air introduction path 40. Air in the atmosphere introduced from the supply air introduction path 40 is cooled to, for example, about 20 ° C. by the air cooling heat exchanger 62. The cooled supply air is compressed by the compressor 32 of the supercharger 30 and then supplied to the cylinder of the main combustion engine 10.

  According to the present embodiment, by using the cold energy held by the heat medium (nitrogen gas) cooled by the cold heat of LNG and using the electric power obtained by the supercharger drive generator 36, it depends on other cold heat sources. Without this, the BOG in the LNG tank 12 can be reliquefied to prevent the pressure in the LNG tank 12 from rising. In addition, cold power generation is performed with the cold heat stored in the heat medium, and the supply air supplied to the main combustion engine 10 can be cooled with the heat medium after being subjected to the cold power generation.

  In the cold power generation, power generation efficiency can be improved by using the retained heat of the exhaust of the main combustion engine 10 as a heat source. When the main combustion engine 10 is a ship propulsion engine, the power obtained by the cold power generation can be used for a part of the propulsion power or for utilities such as air conditioning, air conditioning, and hot water supply in the ship. . Further, when the main combustion engine 10 is provided in an on-shore power generation facility, the main combustion engine 10 can be used as a part of driving power for the main combustion engine 10 or as power for an accessory device. In addition, while using nitrogen gas as a heat medium and not performing cold power generation directly with the cold heat held by LNG, but performing cold heat power generation with the cold heat held by the heat medium, stable cold power generation can be performed.

  Moreover, the output of the main combustion engine 10 can be increased by cooling the supply air supplied to the main combustion engine 10 and increasing the density of the supply air. Furthermore, the cooling water is cooled with a heat medium after being subjected to cold power generation, and the supply air supplied to the main combustion engine 10 using the cooling water having a large specific heat and easy handling, and the high temperature of the main combustion engine 10 Since the parts are cooled, a stable cooling effect can be maintained. Also, in the cooling of the supply air, instead of directly exchanging heat between the LNG and the supply air, which have a very large temperature difference, the heat exchange is performed between the nitrogen gas cooled by the LNG and the supply air. Can be improved.

  Further, in the cooling / heating power generation apparatus 70, a Brayton cycle having a low temperature and good thermal efficiency is formed, and a two-stage Brayton cycle is formed using a two-stage cooling / heating generation apparatus, so that the conversion efficiency to electric power is maximized. can do. In addition, since the supply air supplied to the main combustion engine 10 is cooled by the cold heat held by the heat medium after performing such cold power generation, the exergy efficiency of the cold heat held by the heat medium can be improved.

  In addition, you may make it cool the air supply after compressing with the compressor 34 of the supercharger 30 with the air cooling heat exchanger 62. FIG. Or you may make it provide a heat exchanger in both the inlet_port | entrance and outlet of the supercharger 30, and you may perform both the inlet_port | entrance air supply cooling and the exit air_supply cooling of the supercharger 30 with the same heat exchanger. .

  Further, when a lot of cold energy is required for cooling the supply air supplied to the main combustion engine 10 at a time when the outside air is at a high temperature such as in summer, the second-stage cold energy generation in the cold energy generator 70. The operation of the apparatus may be stopped, and a heat medium having a lower temperature (for example, around −70 ° C.) after completion of the first heat cycle may be circulated to the water cooling heat exchanger 58. Thereby, the temperature of the cooling water circulating through the cooling water closed circuit 60 can be lowered, and the cooling effect of the supply air supplied to the main combustion engine 10 can be increased.

(Modification)
Although the thermal power generation apparatus 70 of the present embodiment forms a Brayton cycle, the thermal power generation may be performed by an apparatus that forms a Rankine cycle. Hereinafter, the basic configuration of the thermal power generation apparatus forming the Rankine cycle will be described with reference to FIG.
In FIG. 5, the cold power generator 72 is provided with a turbine 722, a pump 724, and heat exchangers 726 and 728 in a refrigerant circulation path 720. A generator 730 is connected to the output shaft of the turbine 722. In the refrigerant circuit 72, nitrogen gas is preferably used as a refrigerant, but propane or alternative chlorofluorocarbon can also be used.

  When the refrigerant is sent to the heat exchanger 726 by the pump 724, it is adiabatically compressed. In the heat exchanger 726, the refrigerant is heated (isobaric expansion). As the heating medium used in the heat exchanger 726, for example, seawater or the like is used when the main combustion engine 10 is a marine vessel propulsion engine. When the main combustion engine 10 is provided in an onshore power generation facility, for example, a boiler or the like is used. The refrigerant heated by the heat exchanger 726 is adiabatically expanded by the turbine 722. The refrigerant adiabatically expanded by the turbine 722 is cooled by the heat exchanger 728 (isobaric compression). In the heat exchanger 728, a cooling medium such as nitrogen gas cooled by NG is used as the cooling medium.

  Even if the cold power generator 72 that forms the Rankine cycle is used, the conversion efficiency into electric power can be improved. Further, the supply air supplied to the main combustion engine 10 can be cooled by the cooling medium after being subjected to the cold power generation.

(Embodiment 2)
Next, a second embodiment of the present invention will be described with reference to FIG. In FIG. 6, an exhaust path 80 is provided in the turbine 32 of the supercharger 30, and the exhaust path 80 is connected to an exhaust turbine 86. A reheater 82 is provided in the exhaust path 80, and the exhaust gas that has worked in the turbine 32 is reheated by the reheater 82. The reheater 82 is provided with a heating source introduction path 84, and a high-temperature heating medium is introduced from the heating source introduction path 84. The reheater 82 heats the exhaust with the heating medium.
The exhaust gas heated to a high temperature by the reheater 82 is introduced into the exhaust turbine 86 to rotate the exhaust turbine 86. An exhaust passage 89 is provided in the exhaust turbine 86, and the exhaust passage 89 is led to the cold heat generator 70. After rotating the exhaust turbine 86, the exhaust is introduced into the cold power generator 70 from the exhaust passage 89, and the retained heat is used as a heat source of the cold heat generator 70.

An exhaust turbine drive generator 88 is connected to the output shaft of the exhaust turbine 86. Electric power is generated by the turbine-driven generator 88 by the rotation of the exhaust turbine 86. The electric power generated by the turbine-driven generator 88 is supplied to the reliquefaction device 28 and used as driving power for the reliquefaction device 28. Other configurations are the same as those of the first embodiment, and the same reference numerals are given to the same configurations.
According to the present embodiment, in addition to the operational effects obtained in the first embodiment, the power obtained by both the auxiliary generator 36 and the exhaust turbine drive generator 88 can be used as the power of the reliquefaction device 28.

(Embodiment 3)
Next, a third embodiment of the present invention will be described with reference to FIG. In FIG. 7, a steam turbine 90 and a steam turbine drive generator 92 connected to the output shaft of the steam turbine 90 are provided. Further, the main combustion engine 10 is provided with an exhaust passage 94 led to the steam turbine 90. Exhaust gas generated in the main combustion engine 10 is sent from the exhaust passage 38 to the turbine 32 of the supercharger 30 and part of the exhaust gas is sent from the exhaust passage 94 to the steam turbine 90. The steam turbine 90 is driven by the exhaust gas sent from the main combustion engine 10, and the steam turbine drive generator 92 generates power by driving the steam turbine 90.

  An exhaust path 96 is provided between the steam turbine 90 and the cold power generator 70. The exhaust gas after driving the steam turbine 90 is introduced into the cold power generator 70 via the exhaust passage 96 and used as a heat source of the cold heat generator 70. Other embodiments are the same as those of the second embodiment. According to the present embodiment, the electric power obtained by the steam turbine drive generator 92 can be used for electric power required for the main combustion engine 10 or for other applications.

(Embodiment 4)
Next, a fourth embodiment of the present invention will be described with reference to FIG. This embodiment is a further modification of the second embodiment. In FIG. 8, the cooling water closed circuit 60 has an additional path 60 a that is led to the cooling power generation device 70 on the downstream side of the heat exchange unit 64 and the upstream side of the water cooling heat exchanger 58. As a result, the heat medium flowing through the heat medium closed circuit 52 is heated by the air taken in from the atmosphere by the air cooling heat exchanger 62 and absorbs the heat retained by the main combustion engine 10 by the cooling jacket 64, and then the cold power generator 70. The cold power generation apparatus 70 performs cold power generation using the heat retained by the heat medium. The cooling water after being subjected to the cold power generation is cooled by exchanging heat with the heat medium in the water cooling heat exchanger 58.

In the second embodiment, the cold power generator 70 is operated by the retained heat of the exhaust gas introduced from the exhaust passage 89, but in this embodiment, the exhaust gas discharged to the exhaust passage 89 is purified. After being applied, it is discharged to the outside. Other configurations are the same as those of the second embodiment.
According to the present embodiment, a large amount of heat possessed by the cooling water that has absorbed the heat of the atmosphere and the main combustion engine 10 to become water vapor can be used for the cold power generation of the cold power generator 70. In addition, since the cooling water having a large specific heat is used as the heat medium, the efficiency of heat exchange with the refrigerant used in the cold power generator 70 can be improved.

(Embodiment 5)
Next, a fifth embodiment of the present invention will be described with reference to FIG. In FIG. 9, a cooling jacket 100 is provided at a high temperature portion of the compressor 34 of the supercharger 30. A cooling water circulation path 102 is connected to the cooling jacket 100, and the cooling water circulation path 102 is led to the cold heat generator 70. The cooling water circulation path 102 is provided with a water pump 104 for circulating the cooling water. Cooling water heated at a high-temperature portion of the compressor 34 is sent to the cold heat generator 70 via the cooling water circulation path 102. The cold power generator 70 is driven by the retained heat of the cooling water. The exhaust discharged to the exhaust passage 89 is subjected to a purification process and then discharged to the outside. Other configurations are the same as those of the second embodiment.

  According to the present embodiment, cold power generation can be performed using the compression heat of the supply air generated by the compressor 34.

(Embodiment 6)
Next, a sixth embodiment of the present invention will be described with reference to FIG. In FIG. 10, a cold storage device 110 is provided in the heat medium closed circuit 52 between the cold heat recovery heat exchanger 54 and the reliquefaction device 28. The cool storage device 110 is composed of, for example, a cool storage tank that stores an ethylene glycol-water-based cool storage agent. Other configurations are the same as those of the second embodiment.

  When excessive cooling heat is generated in the heat medium circulating in the heat medium closed circuit 52, nitrogen gas circulating in the heat medium closed circuit 52 is introduced into the cold storage tank 110 to cool the cold storage agent stored in the cold storage device 110. And cold energy can be accumulated. As a result, the amount of cold heat held by the nitrogen gas can be adjusted, and the amount of cold heat that is not excessive or insufficient in the operating conditions can be adjusted. Moreover, the cool heat which the cool storage apparatus 110 holds is discharge | released according to a condition, For example, for the drive of the reliquefaction apparatus 28, it can utilize effectively. Furthermore, by providing the cold storage device 110 in the heat medium closed circuit 52 immediately downstream of the cold heat recovery heat exchanger 54, the cold heat received from the high pressure LNG by the cold heat recovery heat exchanger 54 can be easily stored in the cold storage device 110. There are advantages.

  In the present embodiment, the heat storage device 110 is provided in the heat medium closed circuit 52 between the cold heat recovery heat exchanger 54 and the reliquefaction device 28, but the arrangement position of the cold storage device 110 is particularly at this position. It is not limited.

(Embodiment 7)
Next, a seventh embodiment of the present invention will be described with reference to FIG. In this embodiment, the bypass flow path 120 branched from the heat medium closed circuit 52 between the cold heat recovery heat exchanger 54 and the reliquefaction device 28 and connected to the cold heat recovery heat exchanger 54 on the upstream side of the blower 56 is provided. Is provided. A cold storage device 122 is provided in the bypass channel 120. The cold storage device 122 has the same configuration as the cold storage device 110 of the sixth embodiment. Further, a branch path 124 that branches from the bypass flow path 120 on the downstream side of the regenerator 122 and is connected to the heat medium closed circuit 52 on the upstream side of the reliquefaction apparatus 28 is provided. The heat medium closed circuit 52, the bypass flow path 120, and the branch path 124 are respectively provided with flow rate adjusting valves 126, 128, and 129 at the illustrated positions. Other configurations are the same as those of the second embodiment.

When excessive cooling heat is generated in the nitrogen gas circulating through the heat medium closed circuit 52, the flow rate adjusting valves 126 and 128 are operated to introduce a part of the nitrogen gas into the bypass flow path 120. Excess cold heat is accumulated in the regenerator 122 from the nitrogen gas introduced into the bypass flow path 120.
According to this embodiment, the provision of the bypass flow path 120 facilitates adjustment of the amount of nitrogen gas introduced into the cold storage device 122. Therefore, it becomes easy to adjust the amount of cold heat accumulated in the cold storage device 122. The cold energy accumulated in the cold accumulator 122 can be returned to the heat medium closed circuit 52 via the bypass channel 120 as needed. Further, the accumulated cold heat can be directly supplied to the reliquefaction device 28 by opening the flow rate adjustment valve 129.

(Embodiment 8)
Next, an eighth embodiment of the present invention will be described with reference to FIG. This embodiment is a modification of the sixth embodiment shown in FIG. In FIG. 12, a heating heat exchanger 130 for heating the nitrogen gas circulating in the heat medium closed circuit 52 is provided. For example, a heating medium flow path 132 through which a heating medium such as exhaust gas discharged from the main combustion engine 10 or seawater flows is connected to the heating heat exchanger 130. These heat media exchange heat with nitrogen gas to heat the nitrogen gas. Other configurations are the same as those of the sixth embodiment shown in FIG.

  When the nitrogen gas circulating through the heat medium closed circuit 52 retains excessive cooling heat more than necessary, the heating gas heats the nitrogen gas by the heating heat exchanger 130 to forcibly consume the excessive cooling heat. That is, the amount of cold heat held by the nitrogen gas circulating in the heat medium closed circuit 52 can be balanced by the heating of the nitrogen gas by the heating heat exchanger 130 and the cold storage by the cold storage device 110. Further, based on the temperature of the outside air introduced as the supply air to the main combustion engine 10, the temperature of seawater used as the heating medium of the heating heat exchanger 130, etc. By controlling the operations of the reliquefaction device 28, the cold power generator 70, the water cooling heat exchanger 58 and the cooling jacket 64, the operation of the main combustion engine 10 and the cold power generator 70 can be optimized.

  In each of the embodiments described above, the nitrogen gas circulating in the heat medium closed circuit 52 maintains the inlet supply temperature of the supercharger 30 within a set range, and therefore the following control is performed in response to the flow rate change of the high pressure LNG. Is possible. When the output of the main combustion engine 10 is decreased, the flow rate of the high pressure LNG supplied from the booster pump 22 is controlled to decrease, and at the same time, the circulation flow rate of nitrogen gas is also decreased. On the other hand, when the output of the main combustion engine 10 is increased, the flow rate of the high-pressure LNG supplied from the booster pump 22 is controlled to increase, and at the same time, the circulation flow rate of nitrogen gas is also increased. That is, the control is performed so that the circulation amount of the nitrogen gas is balanced in accordance with the flow rate change (cooling amount fluctuation) of the high-pressure LNG serving as the cooling heat source.

  Further, when the inlet air supply temperature of the supercharger 30 is lower than the set value, it means that low temperature nitrogen gas is excessively supplied to the air cooling heat exchanger 62. Therefore, the temperature of the nitrogen gas supplied to the air-cooling heat exchanger 62 is raised by controlling the first cooling heat consumption source such as the reliquefaction device 28 so that a large amount of cooling heat is consumed. In addition, a bypass flow path is provided in the heat medium closed circuit 52 to reduce the amount of nitrogen gas supplied to the air cooling heat exchanger 62. Alternatively, the operation of the blower 56 is controlled to reduce the circulation flow rate of nitrogen gas. With these controls, the inlet air supply temperature of the supercharger 30 can be optimized. If a nitrogen gas flow path that bypasses the cold heat recovery heat exchanger 54 is provided to adjust the bypass amount, the temperature of the nitrogen gas circulating in the heat medium closed circuit 52 can be adjusted.

  When the inlet air supply temperature of the supercharger 30 rises above the set value, it means that the amount of nitrogen gas supplied to the air cooling heat exchanger 62 is small or the nitrogen gas temperature is high. To do. Therefore, the inlet air supply temperature of the supercharger 30 can be optimized by performing the control opposite to the case where the inlet air supply temperature of the supercharger 30 is lower than the set value.

  ADVANTAGE OF THE INVENTION According to this invention, the thermal efficiency improvement of the combustion engine which uses a low-temperature liquefied fuel as a fuel can be enabled by increasing the utilization efficiency of the cold heat which a low-temperature liquefied fuel holds, and energy saving can be achieved.

DESCRIPTION OF SYMBOLS 10 Main combustion engine 12 LNG tank 14 Submerged pump 16, 20, 24 Supply path 18 Suction drum 22 Booster pump 26 BOG circulation path 28 Reliquefaction device 30 Supercharger 32 Turbine 34 Compressor 36 Supercharger drive generator 38, 44, 80, 89, 96 Exhaust path 40 Supply air introduction path 42 Compressed air supply path 50 Cold heat recovery device 52 Heat medium closed circuit 54 Cold heat recovery heat exchanger 56 Blower 58 Water cooling heat exchanger 60 Cooling water closed circuit 60a Additional path 62 Air-cooled heat exchanger 64,100 Cooling jacket 66,104 Water pump 70, 72 Chilled power generator 700,730 Generator 702,722 Turbine 704 Compressor 706 Output shaft 708,720 Refrigerant circuit 710,712,714,726 728 Heat exchanger 724 Pump 82 Reheater 84 Heating source Inlet path 86 Exhaust turbine 88 Exhaust turbine drive generator 90 Steam turbine 92 Steam turbine drive generator 102 Cooling water circulation path 110, 122 Cold storage device 120 Bypass path 124 Branch path 126, 128, 129 Flow rate adjusting valve 130 Heating heat exchanger 132 Heat medium flow path FS Fuel supply system

Claims (11)

A low temperature liquefied fuel tank for storing the low temperature liquefied fuel; and
A combustion engine that generates power using fuel gas obtained by vaporizing the low-temperature liquefied fuel; and
A turbocharger composed of a turbine section driven by exhaust gas discharged from the combustion engine, and a compressor section that is linked to the turbine section and sends compressed air to the combustion engine;
A booster pump provided in a low-temperature liquefied fuel supply system for supplying the fuel gas into a cylinder of the combustion engine, and for boosting the low-temperature liquefied fuel introduced from the low-temperature liquefied fuel tank;
A heat recovery heat exchanger that heat-exchanges the heat medium flowing through the heat medium closed circuit and the high-pressure low-temperature liquefied fuel boosted by the booster pump, and cools the heat medium;
A boil-off gas which is provided in a boil-off gas circulation path connected to the gas phase part of the low-temperature liquefied fuel tank and flows through the boil-off gas circulation path using the cold heat of the heat medium cooled by the cold recovery heat exchanger. A re-liquefaction part for re-liquefying,
Cold power generation that performs cold power generation using the cold heat held by the heat medium after being subjected to reliquefaction of the boil-off gas in the reliquefaction unit, and the heat held by the combustion engine itself or exhaust gas discharged from the combustion engine And
After cooling by the heat medium that has been provided for reliquefaction of the boil-off gas in the reliquefaction unit, after supply to the combustion engine introduced into the compressor unit of the supercharger or after being pressurized by the compressor unit And an air supply / cooling heat exchanging mechanism for cooling the air supply. The air cooling heat exchange mechanism is
A cooling water closed circuit in which the cooling water circulates,
A water-cooling heat exchanger that cools the cooling water with the cold heat possessed by the heat medium after performing cold-power generation in the cold-power generation unit;
Using cooling water cooled by the water-cooling heat exchanger, the air-cooling heat exchanger configured to cool the air introduced into the compressor unit of the supercharger or the air pressurized by the compressor unit,
The cooling water closed circuit is installed in the combustion engine, and is configured to cool a high-temperature portion of the combustion engine using cooling water obtained by cooling the supply air with the air cooling heat exchanger. The cold heat utilization apparatus of the low-temperature liquefied fuel of Claim 1. Comprising a supercharger-driven generator driven by the output of the supercharger;
While supplying the electric power obtained by the supercharger-driven generator to the reliquefaction unit as auxiliary power,
The cold energy utilization apparatus for low-temperature liquefied fuel according to claim 1 or 2, wherein the cold heat power generation section performs cold power generation using the retained heat of the exhaust gas discharged from the turbine section of the supercharger. An exhaust turbine driven by exhaust discharged from the turbocharger turbine section;
A reheater for reheating the exhaust discharged from the exhaust turbine;
An exhaust turbine drive generator connected to the output shaft of the exhaust turbine,
The electric power obtained by the exhaust turbine drive generator is supplied as auxiliary power to the reliquefaction unit, and the cold heat generation unit performs cold power generation using the retained heat of the exhaust discharged from the exhaust turbine. The cold heat utilization apparatus of the low-temperature liquefied fuel of Claim 3. A steam turbine driven by the exhaust of the combustion engine;
A steam turbine drive generator connected to the output shaft of the steam turbine,
3. The cold energy utilization apparatus for low-temperature liquefied fuel according to claim 1, wherein the cold heat generation unit performs cold power generation using the retained heat of the exhaust discharged from the steam turbine. The cooling water closed circuit is led to the cold power generation unit,
The cold energy utilization apparatus for low-temperature liquefied fuel according to claim 2, wherein the cold heat power generation unit performs cold power generation using the retained heat of the cooling water after cooling a high temperature portion of the combustion engine. A high-temperature portion of the compressor unit of the supercharger and a cooling water circulation path led to the cold power generation unit,
3. The cold energy utilization apparatus for low-temperature liquefied fuel according to claim 1, wherein the cold power generation unit performs cold power generation using the retained heat of the cooling water after cooling the compressor unit. 4.   The cold energy utilization apparatus for low-temperature liquefied fuel according to claim 1, wherein a cold storage device is provided in the heat medium closed circuit or a bypass flow path branched from the heat medium closed circuit. A heating heat exchanger provided in the heat medium closed circuit, for recovering surplus cold heat of the heat medium flowing through the heat medium closed circuit;
The cold energy utilization device for low-temperature liquefied fuel according to claim 8, wherein the amount of cold heat stored in the heat medium closed circuit is adjusted by adjusting a heat storage amount of the cold storage device and a heat exchange amount of the heating heat exchanger. .   The cold heat generating unit according to claim 1, wherein the cold power generation unit includes a heat engine that forms a Brayton cycle or a Rankine cycle. The cold power generation unit is composed of a heat engine that forms a two-stage Brayton cycle,
The air cooling heat exchange mechanism cools the air introduced into the compressor unit of the supercharger or the air after being pressurized by the compressor unit with the heat medium after performing the cold power generation in the cold power generation unit. The cold heat utilization apparatus of the low-temperature liquefied fuel of Claim 10 characterized by the above-mentioned.

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