JP2018150899A - Gas cooling system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently cool gas introduced to a compressor.SOLUTION: A gas cooling system 100 includes: a gas flow passage for guiding gas G discharged from a storage tank 20 to a high-pressure injection type engine 10; at least two or more gas compression sections 40 for compressing the gas G; a gas cooling section 50 for cooling the gas G compressed by the gas compression sections 40; a thermoacoustic engine 60; a heating medium flow passage 70 for guiding a heating medium 71 that has collected waste heat from the high-pressure injection type engine 10 to a heater 62a of the thermoacoustic engine 60; and a refrigerant flow passage 80 for guiding a refrigerant 81 of which heat has been absorbed by a heat absorber 63a of the thermoacoustic engine 60 to the gas cooling section 50.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a gas cooling system that cools a gas obtained from a storage tank that stores liquefied natural gas.

  In a transport ship that transports liquefied natural gas, boil-off gas is inevitably generated from a storage tank that stores liquefied natural gas. In a ship, it is described that boil-off gas discharged from a storage tank is compressed in stages by a plurality of compression units and supplied to an engine of a transport ship, and the boil-off gas is used as power for the transport ship. And since the boil-off gas compressed by each compression part will heat up, in order to maintain the operating efficiency of each compression part high, the cooling part which cools the boil-off gas after compression is in the downstream of each compression part. Is provided.

Japanese Patent Laid-Open No. 2006-128737

  However, in order to maintain high operating efficiency of each compression section, it is preferable that the boil-off gas introduced into the compression section is at a low temperature (for example, around 0 ° C.). For this purpose, a heat pump or the like for cooling the boil-off gas is used. Equipment is required and fuel for operation of the equipment is required. In addition to boil-off gas, liquefied natural gas may be extracted from the storage tank by a pump, and the gas vaporized by the vaporizer may be used for the power of the transport ship. There is a similar problem.

  This invention is made | formed in view of the above-mentioned subject, The objective is to provide the gas cooling system which can cool the gas introduce | transduced into a compression part efficiently.

The characteristic configuration of the gas cooling system for achieving the above object is as follows:
A high-pressure injection engine,
A storage tank for storing liquefied natural gas;
A gas flow path for guiding at least part of the gas obtained from the storage tank to the high-pressure injection engine;
At least one gas compression section provided in the gas flow path for compressing the gas;
At least one gas cooling unit for cooling the gas compressed by the gas compression unit;
An acoustic cylinder filled with a working medium and in which sound waves propagate, a heater that heats the working medium from the outside, a cooler that cools the working medium from the outside, and the acoustic energy of sound waves between the heater and the cooler At least one prime mover comprising a sound regenerator for amplifying the sound, and a heat absorber that absorbs heat from the outside of the working medium, a radiator that radiates heat from the working medium, and between the heat absorber and the radiator A thermoacoustic engine provided with at least one acoustic heat pump unit including a temperature difference regenerator that compresses and expands in a form in which sound waves consume acoustic energy;
A heat medium flow path for guiding a heat medium that has recovered exhaust heat from the high-pressure injection engine to the heater;
A refrigerant flow path for guiding the refrigerant absorbed by the heat absorber to the gas cooling unit.

  According to the above characteristic configuration, the exhaust heat from the high pressure injection engine is converted into cold heat by the thermoacoustic engine, and the gas compressed by the gas compression unit is cooled by the cold heat. Thus, since the exhaust heat from the high-pressure injection type engine is used to cool the gas without using fuel, the gas can be efficiently cooled.

Further features of the gas cooling system
Two or more gas compression sections and gas cooling sections are provided,
The refrigerant flow path includes a refrigerant distribution unit that distributes and supplies the refrigerant to each of the gas cooling units.

  According to the above characteristic configuration, since the refrigerant from the heat absorber is distributed and supplied to each gas cooling unit by the refrigerant distribution unit, the apparatus configuration can be simplified.

Further features of the gas cooling system
Shimizu acquisition department to acquire Shimizu,
And a fresh water flow path for guiding the fresh water to the cooler and the radiator.

  In a thermoacoustic engine, a refrigerant that cools the cooler and a medium that receives heat from the heatsink are required. However, according to the above configuration, abundant resources can be obtained by converting seawater that exists infinitely into fresh water. Since the fresh water that can be obtained is used as the refrigerant and medium, resources can be omitted.

Further features of the gas cooling system
Shimizu acquisition department to acquire Shimizu,
And at least one heat exchanger that cools the gas compressed by the gas compression unit with the fresh water from the fresh water acquisition unit on the upstream side of the gas cooling unit.

  The gas compressed in the gas compression section has a certain temperature (for example, about 100 ° C.), and it requires considerable cooling to cool it to around 0 ° C. On the other hand, according to the above configuration, the gas can be cooled to a certain temperature (about 40 ° C.) by exchanging heat with fresh water that can be obtained abundantly as a resource of the high-temperature gas after passing through the gas compression unit, By cooling the gas after cooling to some extent with the refrigerant from the heat absorber of the thermoacoustic engine, the cold heat from the heat absorber necessary for cooling the gas can be efficiently reduced.

Further features of the gas cooling system
The said fresh water acquisition part exists in the point provided with the pump which pumps up seawater, and the water generator which makes the said fresh water from the said pumped-up sea water.

  According to this configuration, seawater existing almost infinitely is converted into fresh water, so that resources for cooling each part of the system can be omitted.

Further features of the gas cooling system
The high-pressure injection engine is for ship propulsion,
It is in the point used for a ship.

  According to this configuration, the gas can be efficiently cooled using the exhaust heat generated by the operation of the high-pressure injection engine for marine propulsion.

Schematic configuration diagram of a gas cooling system according to the present embodiment

  Hereinafter, an embodiment of a gas cooling system according to the present application will be described with reference to the drawings. The gas cooling system 100 according to the present embodiment is provided in a ship such as an LNG tanker, and uses a boil-off gas G as a gas obtained from the storage tank 20. As shown in FIG. 1, the gas cooling system 100 according to the present embodiment includes at least a high-pressure injection engine 10, a storage tank 20 that stores liquefied natural gas, and a boil-off gas G obtained from the storage tank 20. A part of the gas passage 30 that leads partly to the high-pressure injection engine 10, at least one gas compressor 40 that compresses the boil-off gas G provided in the gas passage 30, and the gas compressor 40 compresses the gas At least one gas cooling unit 50 that cools the boil-off gas G, an acoustic cylinder 61 that is filled with the working medium and propagates sound waves, a heater 62a that heats the working medium from the outside, and a cooler 62b that cools the working medium from the outside And at least one prime mover 62 including a sound regenerator 62c for amplifying acoustic energy of sound waves between the heater 62a and the cooler 62b. (In this embodiment, one is used), and the sound wave consumes acoustic energy between the heat absorber 63a in which the working medium absorbs heat from the outside, the heat sink 63b in which the working medium radiates heat to the outside, the heat absorber 63a, and the heat radiator 63b. A thermoacoustic engine 60 provided with at least one acoustic heat pump unit 63 including a temperature difference regenerator 63c that compresses and expands in a form, and a heat medium 71 that recovers exhaust heat from the high-pressure injection engine 10 to the heater 62a. A heat medium passage 70 for guiding and a refrigerant passage 80 for guiding the refrigerant 81 absorbed by the heat absorber 63a to the gas cooling unit 50 are provided. As described above, the gas cooling system 100 according to the present embodiment cools the boil-off gas G discharged from the storage tank 20 storing liquefied natural gas using the thermoacoustic engine 60. Below, the thermoacoustic engine 60 is demonstrated first, and the gas cooling system 100 whole is demonstrated after that.

  The thermoacoustic engine 60 includes an acoustic cylinder 61 formed by connecting a first loop pipe 61a and a second loop pipe 61b, which are filled with a working medium and propagate a sound wave, via a connecting pipe. In the first embodiment, the thermoacoustic engine 60 includes: The first loop pipe 61a is provided with a single prime mover 62, and the second loop pipe 61b is provided with a single acoustic heat pump unit 63.

  Hereinafter, a heater 62a that heats the working medium from the outside, a cooler 62b that cools the working medium from the outside, and an acoustic regenerator 62c that amplifies acoustic energy of sound waves between the heater 62a and the cooler 62b. A description will be given of the prime mover 62.

  Although not shown in detail, the heater 62a includes a jacket portion (not shown) through which the heat medium 71 flows and fins (not shown) extending from the jacket portion to the inside of the first loop pipe 61a. Become. The heater 62a heats the working medium in such a form that the fins are heated by the heat medium 71 flowing through the jacket portion, and heat is conducted from the fins to the working medium inside the first loop pipe 61a.

  The cooler 62b includes a jacket portion (not shown) through which fresh water W as a refrigerant flows, and fins (not shown) extending from the jacket portion to the inside of the first loop pipe 61a. The cooler 62b cools the working medium in such a form that the fin is cooled by the fresh water W flowing through the jacket portion, and cool heat is conducted from the fin to the working medium inside the first loop pipe 61a.

The sound regenerator 62c provided between the heater 62a and the cooler 62b is, for example, in a state where the plate surface is along the direction orthogonal to the cylinder axis direction of the first loop pipe 61a and the cylinder axis direction. A plurality of thin plate-like members (not shown) arranged along.
For example, the thin plate member has a thickness of 50 μm or more and 100 μm or less, and is provided with about 300 to 600 sheets. The thin plate member is provided with a large number of through holes (not shown) penetrating in a direction along the axial direction of the cylinder with a diameter of about 100 μm to 300 μm.

The working medium exists in the acoustic cylinder 61 in a state in which minute fluctuations are generated in the axial direction of the cylinder. In other words, the sound wave propagating through the working medium forms a traveling wave from one side to the other side and a traveling wave from the other side to the one side between both the heater 62a and the cooler 62b.
When the sound wave propagating through the working medium forms a traveling wave from the cooler 62b to the heater 62a side, it passes through the plurality of through holes of the thin plate member as the acoustic regenerator 62c in the vicinity of the heater 62a. In addition to being heated in contact with the inner wall of the through hole, it is expanded by being directly heated by the fins of the heater 62a. On the other hand, when the sound wave propagating through the working medium forms a traveling wave from the heater 62a toward the cooler 62b, the sound wave propagating through the plurality of through holes of the thin plate member as the acoustic regenerator 62c in the vicinity of the cooler 62b. As it passes, it cools in contact with the inner wall of the through-hole, and shrinks by being directly cooled by the fins of the cooler 62b.
Thereby, the sound energy as the traveling wave causes self-excited vibration, and the thermal energy is converted into the acoustic energy of the sound wave in such a form that the acoustic energy is amplified.

  The working medium can be composed of a gas that propagates sound waves. Here, since it is desirable that heat exchange in the sound regenerator 62c be performed quickly, helium and hydrogen having a high thermal diffusion coefficient are desirable as the working medium. For the purpose of power generation, since a gas having a high molecular weight is desirable, a gas such as argon may be mixed. In this embodiment, helium is used as the working medium because it is thermally stable.

The acoustic energy of the sound wave amplified by the prime mover 62 propagates from the first loop tube 61a of the acoustic cylinder 61 to the acoustic heat pump unit 63 provided in the second loop tube 61b.
The acoustic heat pump unit 63 is configured such that sound waves consume acoustic energy between the heat absorber 63a in which the working medium absorbs heat from the outside, the radiator 63b in which the working medium radiates heat to the outside, and the heat absorber 63a and the heat radiator 63b. It comprises a temperature difference regenerator 63c that compresses and expands.

Although detailed illustration is omitted, the heat absorber 63a includes a jacket part (not shown) through which the refrigerant 81 flowing in the refrigerant flow path 80 flows, and fins (from the jacket part to the inside of the second loop pipe 61b). (Not shown). In the heat absorber 63a, the fin absorbs heat from the refrigerant 81 flowing through the jacket portion, and the working medium inside the second loop pipe 61b absorbs heat from the fin.
On the other hand, the radiator 63b includes a jacket portion (not shown) through which fresh water W as a refrigerant flows, and fins (not shown) extending from the jacket portion to the inside of the second loop pipe 61b. In the radiator 63b, the working medium inside the second loop pipe 61b radiates heat to the fin, and the fin radiates heat to the fresh water W flowing through the jacket portion.

Here, the acoustic heat pump unit 63 compresses the sound wave propagating through the working medium to form a traveling wave from the heat absorber 63a to the heat radiator 63b, and travels from the heat radiator 63b to the heat absorber 63a. The heat absorber 63a, the temperature difference regenerator 63c, and the heat radiator 63b are arranged at appropriate positions in the second loop pipe 61b so as to expand when forming the.
As a result, when the sound wave propagating through the working medium forms a traveling wave from the heat absorber 63a to the radiator 63b, the temperature is increased by absorbing heat while compressing by the temperature difference regenerator 63c, and the radiator 63b Dissipates heat when the temperature rises to a high temperature.
On the other hand, when the sound wave propagating through the working medium forms a traveling wave from the radiator 63b to the heat absorber 63a, the temperature difference regenerator 63c dissipates heat while cooling and the temperature is lowered by the heat absorber 63a. It absorbs heat at a low temperature.
Incidentally, as described above, in the step of absorbing heat while compressing by the temperature difference regenerator 63c and the step of dissipating heat while expanding, the acoustic energy of the sound wave is consumed and the sound wave is attenuated. Since the replenishment is performed sequentially, the heat pump function of the acoustic heat pump unit 63 is maintained.

The temperature difference regenerator 63c provided between the heat absorber 63a and the heat dissipator 63b may be the same in shape or material as that of the sound regenerator 62c, or different in shape or material. May be.
Note that the tube diameter, tube length, shape, and the like of the acoustic cylinder 61 are based on the hole diameters of the through holes of the sound regenerator 62c and the temperature difference regenerator 63c, and the conversion efficiency from the heat energy of the prime mover 62 to acoustic energy. The acoustic heat pump unit 63 is appropriately set so that the conversion efficiency from acoustic energy to thermal energy is increased.

Next, the gas cooling system 100 according to the present embodiment will be described.
First, a gas cooling system 100 according to the present embodiment is used in a ship that transports liquefied natural gas such as an LNG tanker, and includes a high-pressure injection engine 10 for propelling a ship and a storage tank 20 that stores liquefied natural gas. A gas passage 30 that guides the boil-off gas G obtained from the storage tank 20 to the high-pressure injection engine 10, and at least two or more (this embodiment) that compresses the boil-off gas G provided in the gas passage 30. 4) gas compression section 40 in the form.
That is, in a ship provided with the present system 100, after the boil-off gas G obtained from the storage tank 10 is compressed stepwise by the gas compression unit 40 and the boil-off gas G is increased to a level that can be used for the high-pressure injection engine 10. The boil-off gas G is supplied to the high-pressure injection engine 10 for ship propulsion, and the boil-off gas G is used as power for the ship. The gas obtained from the storage tank 20 is not limited to the boil-off gas G that is naturally discharged from the storage tank 20, but is a gas that is extracted from the storage tank 20 by a pump (not shown) and vaporized by a vaporizer. Also good.

The boil-off gas G is heated by being compressed by the gas compression unit 40, but the boil-off gas G introduced into the gas compression unit 40 is at a low temperature in order to maintain high operation efficiency of the gas compression unit 40. Therefore, a gas cooling unit 50 that cools the boil-off gas G from a temperature TH (for example, 40 ° C.) to a temperature TL (for example, 0 ° C.) is provided between the adjacent gas compression units 40 (this book). In the embodiment, a total of three are provided).
Note that the gas cooling unit 50 is not provided between the two gas compression units 40 on the most upstream side. Since the boil-off gas G immediately after being discharged from the storage tank 20 has an extremely low temperature, the boil-off gas G does not rise to a temperature that requires cooling even when compressed by the most upstream gas compression unit 40. This is because it is not necessary to provide the gas cooling unit 50 between the two gas compression units 40 on the upstream side.

And in order to obtain the cold for cooling the boil-off gas G in the gas cooling part 50, in the gas cooling system 100 which concerns on this embodiment, the exhaust heat from said thermoacoustic engine 60 and the high pressure injection engine 10 is collect | recovered. The heat medium passage 70 that guides the heat medium 71 (such as engine cooling medium such as oil, for example, about 250 ° C.) 71 to the heater 62a, and the refrigerant 81 that has absorbed heat by the heat absorber 63a And a refrigerant flow path 80 for guiding the refrigerant.
That is, the gas cooling system 100 according to the present embodiment converts the exhaust heat from the high pressure injection engine 10 into cold heat by the thermoacoustic engine 60, and cools the boil-off gas G compressed by the gas compression unit 40 by the cold heat. It is like that. Thus, since the exhaust heat from the high-pressure injection engine 10 is used to cool the boil-off gas G without using fuel, the boil-off gas G can be efficiently cooled.
In the present embodiment, the heat medium flow passage 70 is a circulation path in which the heat medium 71 circulates between the high pressure injection engine 10 and the heater 62a, and the refrigerant flow passage 80 is a refrigerant 81 in which the heat absorber 63a and the gas are circulated. It takes the form of a circulation path that circulates between the cooling section 50.

  Further, in the present embodiment, the refrigerant flow path 80 includes a refrigerant distribution unit 82 that distributes and supplies the refrigerant 81 to each gas cooling unit 50. Specifically, the refrigerant distributor 82 includes a distributor 82a that distributes the refrigerant 81 and a distribution path 82b that supplies the refrigerant 81 to each gas cooling unit 50. The refrigerant 81 distributed by the distributor 82a Each gas cooling unit 50 is supplied via each distribution path 82b.

  In addition, the gas cooling system 100 according to the present embodiment includes a fresh water acquisition unit that acquires fresh water W (not shown), a fresh water W that is cooled by a cooler 62b (more specifically, a jacket portion of the cooler 62b), and a radiator 63b (more specifically, And a fresh water passage (not shown) respectively led to the jacket of the radiator 63b. Specifically, in this embodiment, as a fresh water acquisition unit that acquires fresh water W, a pump that pumps sea water from the surroundings and a water generator that creates fresh water W from the pumped sea water are used to Fresh water W is obtained from infinitely existing seawater. In the thermoacoustic engine 60, a refrigerant that cools the cooler 62b and a medium that receives heat from the radiator 63b are required. In the gas cooling system 100 according to the present embodiment, the refrigerant and the medium are Because the seawater that exists almost infinitely is used, resources are omitted.

  In this embodiment, the heat exchanger 90 which cools the boil-off gas G compressed by the gas compression part 40 with the fresh water W from the said fresh water acquisition part in the upstream of each gas cooling part 50 is provided. That is, the boil-off gas G can be cooled to a certain temperature TH (for example, about 40 ° C.) by first exchanging heat with the fresh water W by the heat exchanger 90 after passing through the gas compression unit 40. By cooling the boil-off gas G after being cooled to some extent with the refrigerant 81 from the heat absorber 63a of the thermoacoustic engine 60, the cold heat from the heat absorber 63a necessary for cooling the boil-off gas G can be efficiently reduced. . Further, the temperature of the boil-off gas G introduced into the gas cooling unit 50 can be stabilized by the heat exchanger 90, and the operation of the gas cooling unit 50 can be stabilized.

  As described above, according to the gas cooling system 100 according to the present embodiment, the boil-off gas is used by using the exhaust heat or seawater from the high-pressure injection engine 10 without using a separate fuel for cooling the boil-off gas G. G can be efficiently cooled.

[Another embodiment]
(1) In the said embodiment, in one thermoacoustic engine 60, while providing the some motor | power_engine 62, you may employ | adopt the structure provided with the some acoustic heat pump part 63. FIG.
Moreover, in the said embodiment, although the system 100 showed the structural example provided with one thermoacoustic engine, the structure provided with two or more thermoacoustic engines is also included in the scope of this application.

(2) In the above-described embodiment, the acoustic cylinder has been shown as a configuration example including two loop tubes. However, a configuration including three or more loop tubes may be adopted, or a configuration including a single loop tube May be adopted.

(3) In the said embodiment, the gas cooling system 100 showed the example which is provided in a ship.
However, the gas cooling system can be applied to other than ships, and can be suitably applied to, for example, an LNG base that receives LNG from an LNG tanker on the shore.

(4) In the above embodiment, fresh water W is used as a refrigerant for cooling the cooler 62b, a medium that receives heat from the radiator 63b, and a refrigerant in the heat exchanger 90. However, other than the fresh water W, such as using the pumped seawater as it is, may be adopted as the refrigerant or medium.

(5) In the above embodiment, the example in which the heat exchanger 90 is provided on the upstream side of the gas cooling unit 50 has been shown, but the heat exchanger 90 may not be provided.

(6) In the above-described embodiment, an example in which three or more gas compression units 40 are provided and the refrigerant flow path 80 includes the refrigerant distribution unit 82 has been described. The refrigerant distribution part 82 may not be provided in the flow path 80.

(7) The gas flow path 30 only needs to guide at least a part of the gas discharged from the storage tank 20 to the high-pressure injection engine 10, and the other part of the gas obtained from the storage tank 20 is It may be used for other applications such as being re-liquefied and returned to the storage tank 20.

  The configuration disclosed in the above embodiment (including another embodiment, the same shall apply hereinafter) can be applied in combination with the configuration disclosed in the other embodiment, as long as no contradiction occurs. The embodiment disclosed in this specification is an exemplification, and the embodiment of the present invention is not limited to this. The embodiment can be appropriately modified without departing from the object of the present invention.

  The gas cooling system of the present invention can be effectively used as a gas cooling system for cooling gas obtained from a storage tank that stores liquefied natural gas.

DESCRIPTION OF SYMBOLS 10: High pressure injection type engine 20: Storage tank 30: Gas flow path 40: Gas compression part 50: Gas cooling part 60: Thermoacoustic engine 61: Acoustic cylinder 62: Motor | generator 62a: Heater 62b: Cooler 62c: Sound reproduction | regeneration Unit 63: Acoustic heat pump unit 63a: Heat absorber 63b: Radiator 63c: Temperature difference regenerator 70: Heat medium passage 71: Heat medium 80: Refrigerant passage 81: Refrigerant 82: Refrigerant distributor 90: Heat exchanger 100: Gas cooling system G: Boil-off gas (gas)
W: Shimizu

Claims (6)

A high-pressure injection engine,
A storage tank for storing liquefied natural gas;
A gas flow path for guiding at least part of the gas obtained from the storage tank to the high-pressure injection engine;
At least one gas compression section provided in the gas flow path for compressing the gas;
At least one gas cooling unit for cooling the gas compressed by the gas compression unit;
An acoustic cylinder filled with a working medium and in which sound waves propagate, a heater that heats the working medium from the outside, a cooler that cools the working medium from the outside, and the acoustic energy of sound waves between the heater and the cooler At least one prime mover comprising a sound regenerator for amplifying the sound, and a heat absorber that absorbs heat from the outside of the working medium, a radiator that radiates heat from the working medium, and between the heat absorber and the heat radiator A thermoacoustic engine provided with at least one acoustic heat pump unit including a temperature difference regenerator that compresses and expands in a form in which sound waves consume acoustic energy;
A heat medium flow path for guiding a heat medium that has recovered exhaust heat from the high-pressure injection engine to the heater;
A gas cooling system comprising: a refrigerant flow path that guides the refrigerant absorbed by the heat absorber to the gas cooling unit. Two or more gas compression sections and gas cooling sections are provided,
The gas cooling system according to claim 1, wherein the refrigerant flow path includes a refrigerant distribution unit that distributes and supplies the refrigerant to each of the gas cooling units. Shimizu acquisition department to acquire Shimizu,
The gas cooling system according to claim 1, further comprising a fresh water passage that guides the fresh water to the cooler and the radiator. Shimizu acquisition department to acquire Shimizu,
The at least 1 heat exchanger which cools the gas compressed by the gas compression part with the fresh water from the fresh water acquisition part in the upper stream side of the gas cooling part. The gas cooling system according to one item.   The gas cooling system according to claim 3 or 4, wherein the fresh water acquisition unit includes a pump that pumps seawater and a water generator that creates the fresh water from the pumped seawater. The high-pressure injection engine is for ship propulsion,
The gas cooling system as described in any one of Claims 1-5 used for a ship.

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