JP2007083851A - Superconducting equipment cooling system and liquefied natural gas tanker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cooling system for a superconducting device and a liquefied natural gas tanker capable of obtaining efficient propulsion using a superconducting motor and maintaining the superconducting motor at a low temperature without using a separate cooling source or a large cooling device. Provide offer.
A cooling container capable of keeping a superconducting motor at a low temperature by being filled with a superconducting cooling medium in a state in which the superconducting motor used in a propulsion device for a liquefied natural gas tanker that conveys liquefied natural gas is accommodated, and vaporization A compressing means for raising the temperature of the superconducting cooling medium by compressing it, a heat exchanging means for cooling the heated superconducting cooling medium with a cold source of liquefied natural gas, and depressurizing the cooled superconducting cooling medium And a pressure reducing means for lowering the temperature.
[Selection] Figure 1

Description

  The present invention relates to a cooling system for a superconducting device and a liquefied natural gas tanker, and more particularly, to a liquefied natural gas tanker that obtains propulsion using liquefied natural gas mounted on a liquefied natural gas tanker, and a superconducting device for obtaining this propulsive force. It is used for cooling.

  FIG. 5 is a diagram showing a configuration of a conventional liquefied natural gas tanker 90. This liquefied natural gas tanker 90 is vaporized when the temperature of the liquefied natural gas serving as a transport reference is increased and the tank portion 91 that stores the liquefied natural gas. The steam turbine engine 92 that obtains driving force by rotating the steam turbine with the steam generated using the heat obtained by burning the natural gas, and the driving force obtained by the steam turbine engine 92 A shaft 93 that transmits to the outside, a propeller 94 that obtains a propulsive force using this driving force, and a rudder plate 95 for controlling the traveling direction of the tanker 90 are provided.

  The liquefied natural gas tanker 90 has a double hull structure (referred to as a double hull) so that the tank portion 91 is disposed at a position away from the bottom of the ship so that it can be transported in the event of a collision or grounding accident. Preventing spillage is being done. Japanese Patent Laid-Open No. 10-7071 (Patent Document 1) discloses that tank portions 91a to 91c are formed in several sections, and the tank portion 91a of the bow portion is arranged at a position further away from the ship bottom. In particular, it is described that the tank portion 91a can be prevented from being damaged particularly in a portion that is most easily damaged during a collision.

JP-A-10-7071

  However, in the conventional liquefied natural gas tanker 90, a heavy steam turbine engine 92 that generates driving force is disposed at the center of the hull, and it is necessary to provide a shaft 93 for transmitting power from the steam turbine engine 92 to the propeller 94. As a result, there is a problem that it is difficult to form a double hull structure. That is, the portion where the steam turbine engine 92 and the shaft 93 are provided interferes with the double hull structure, causing a problem that the volumes of the tank portions 91b and 91c have to be reduced.

  Therefore, instead of the configuration in which the driving force from the steam turbine engine 92 is directly transmitted to the propeller 94, the driving force obtained from the steam turbine engine 92 is temporarily converted into electric energy by a generator 96 as shown in FIG. Then, it is considered to obtain a propulsive force by driving the pod type propulsion device 97 with this electric energy. The pod type propulsion device 97 is configured so as to obtain a larger propulsive force by incorporating a large motor 98, and in addition to this, a sufficient propulsive force can be obtained by increasing the number of pod type propulsion devices 97. I was trying to get it.

  However, when a plurality of large pod type propulsion devices 97 are formed, not only the manufacturing cost is increased, but also a loss occurs in each motor 98 in each pod type propulsion device 97, so that the fuel consumption rate is deteriorated. was there. Therefore, it is conceivable that the motor 98 provided in the pod type propulsion device 97 is a superconducting motor, so that the motor can be reduced in size, increased in output and reduced in energy consumption. In this case, the superconducting motor is cooled. Various inconveniences such as a separate cooling device and a need to separately provide a tank for storing liquid nitrogen or the like serving as a cooling heat source for cooling the superconducting motor are inevitable.

  The present invention has been made in consideration of the above problems, and its purpose is to obtain an efficient driving force using a superconducting device, and to provide a superconducting device without using a separate cooling heat source or a large-scale cooling device. To provide a cooling system for a superconducting device and a liquefied natural gas tanker that can be kept at a low temperature.

In order to solve the above problems, the present invention provides:
Superconducting equipment used in propulsion devices for liquefied natural gas tankers that transport liquefied natural gas;
A cooling container capable of keeping the superconducting device in a low temperature state by being filled with a superconducting cooling medium in a state in which the superconducting device is accommodated;
Compression means for heating the vaporized superconducting cooling medium by compressing it,
A heat exchange means for cooling the heated superconducting cooling medium with a cold source of liquefied natural gas;
There is provided a cooling system for a superconducting device, comprising a pressure reducing means for reducing the temperature of the cooled superconducting cooling medium by reducing the pressure.

  According to the above configuration, the superconducting cooling medium heated by compression by the compressing means is cooled by the liquefied natural gas in the heat exchanging means, and further, the superconducting cooling medium is liquefied natural gas by reducing the temperature by reducing the pressure by the depressurizing means. It cools so that it may become a temperature lower than the temperature (110K). Without providing a separate heat source just for cooling the superconducting equipment, the existing liquefied natural gas can be effectively used to sufficiently cool the superconducting equipment and maintain the superconducting state. Thus, efficient conversion between electric energy and driving force can be performed, and a larger driving force can be obtained using a smaller superconducting device.

  The superconducting device includes a superconducting motor that converts electric energy into driving force, a superconducting generator that converts driving force into electric energy, a superconducting power storage device (SMES), and the like.

  Any superconducting cooling medium may be used as long as it has a liquefaction temperature (boiling point) lower than that of LNG, and in addition to nitrogen, neon, hydrogen, and helium, argon or oxygen may be used. Further, the superconducting cooling medium is preferably inert, and the following description shows an example using nitrogen, and in this case, the temperature of the superconducting device can be lowered to about 70K. Here, a large amount of energy is required to lower the temperature of the superconducting device from room temperature (about 300K) to about 70K, but it is performed with relatively little energy from the temperature of the LNG (about 110K) to about 70K. be able to.

The present invention also provides:
A tank section for storing liquefied natural gas;
A power generation device that generates electric energy using natural gas obtained by vaporizing the liquefied natural gas;
A superconducting motor that obtains driving force using electrical energy, and a propulsion device that obtains propulsive force using the driving force of this superconducting motor, and
A cooling container capable of maintaining the superconducting motor in a low temperature state by being filled with the superconducting cooling medium in a state in which the superconducting motor is accommodated, and compression means for raising the temperature by compressing the vaporized superconducting cooling medium; It has a cooling system comprising a heat exchanging means for cooling a heated superconducting cooling medium with a liquefied natural gas cooling source, and a decompressing means for lowering the temperature of the cooled superconducting cooling medium by reducing the pressure. A liquefied natural gas tanker is provided.

  According to the said structure, since a superconducting motor is small and high output compared with a normal motor, a propulsion apparatus can be reduced in size and sufficient propulsive force can be obtained to a liquefied natural gas tanker using fewer propulsion apparatuses. Moreover, the cold heat source for cooling the superconducting motor is liquefied natural gas consumed for driving the power generation apparatus, and it is not necessary to mount a separate cold heat source on the liquefied natural gas tanker.

The present invention also provides:
A tank section for storing liquefied natural gas;
A superconducting power generation device having a winding made of a superconducting material that generates electric energy using natural gas vaporized from the liquefied natural gas;
A motor that obtains driving force using electric energy, and a propulsion device that obtains driving force using the driving force of the motor; and
A cooling container capable of maintaining the superconducting power generation device in a low temperature state by being filled with the superconducting cooling medium in a state in which the superconducting power generation device is accommodated, and a compression means for raising the temperature by compressing the vaporized superconducting cooling medium. And a heat exchanging means for cooling the heated superconducting cooling medium with a liquefied natural gas cooling source, and a depressurizing means for lowering the temperature by depressurizing the cooled superconducting cooling medium. A liquefied natural gas tanker is provided.

  According to the above configuration, since the superconducting power generation device is smaller and has a higher output than a normal power generation device, sufficient power can be obtained to drive a high-output motor using fewer power generation devices. In addition, since the superconducting power generator has an extremely small energy loss, the fuel consumption rate can be dramatically improved. In addition, the cold heat source for cooling the superconducting power generation device is liquefied natural gas consumed to drive the superconducting power generation device, and it is not necessary to mount a separate cold heat source on the liquefied natural gas tanker. Furthermore, a combination of a cold insulation container that can keep the superconducting power generation apparatus in a low temperature state while accommodating the superconducting power generation apparatus and a cold insulation container that can keep the superconducting motor in a low temperature state while accommodating the superconducting motor is used. It goes without saying that the fuel consumption rate can be improved as much as possible.

  The power generation device may comprise an engine such as a steam turbine engine or a diesel engine that obtains driving force using natural gas vaporized in the tank part or liquefied natural gas in the tank part, and a generator provided on the output drive shaft of the engine. Conceivable. Alternatively, the power generation device may include a reforming device that reforms natural gas into hydrogen and a fuel cell. Even if the temperature of the natural gas consumed by the power generator such as an engine or a fuel cell is already vaporized, even if it is in a mist state, it becomes a cold source of about 110K, which is the boiling point of liquefied natural gas, and the outside temperature is about 300K. It is sufficiently low in temperature. In this sense, the cold source of the superconducting cooling medium heated by compression is liquefied natural gas.

  The propulsion device is preferably a pod type propulsion device. In this case, since the liquefied natural gas tanker can be steered and propelled at the same time, the characteristics of the superconducting motor that is efficient and can obtain a stronger propulsive force can be effectively utilized. Since the pod type propulsion device is attached to the outside of the hull, the space on the ship can be expanded. Further, since the motor is small in the pot type propulsion device, the outer diameter of the pod main body is thin and the propulsion efficiency can be improved.

  It is preferable that the tank part is disposed at a position away from the ship bottom by a double hull structure. In other words, compared to the conventional liquefied natural gas tanker using the shaft 93 for transmitting the driving force to the propeller 94, a double hull structure is formed by adopting a pod type propulsion device, and the tank at the time of collision The size of the tank part can be kept large at the same time while protecting the part.

  It is preferable that each of the power generation devices has a plurality of power generation units that share electric power to generate electric energy. Since each power generation unit is small, a power generation device can be provided in a portion that is a dead space in the ship, and the size of the tank unit can be increased as much as possible. Even if the power generation unit consists of an engine that generates driving force using natural gas as fuel and a generator that generates power using the driving force of this engine, it generates hydrogen gas by reforming natural gas. It may consist of a reformer and a fuel cell. When a generator is used in the power generation unit, it is preferable that the generator is a superconducting generator (superconducting device). In this case, the liquefied natural gas tanker preferably has a cooling system for cooling the superconducting generator.

  As described above, according to the present invention, cooling of a superconducting motor, which is a problem when a superconducting device such as a superconducting motor is employed in a propulsion device for a liquefied natural gas tanker, is consumed to obtain the propulsive force of the liquefied natural gas tanker. Therefore, the superconducting equipment can be kept at a low temperature without using a special cold heat source. It takes a lot of energy to cool from a room temperature of about 300K to a low temperature state (about 70K) where a superconducting device such as a superconducting motor is stably kept in a superconducting state, but liquefied natural gas having a boiling point of about 110K is required. By using it, it can be easily cooled to the low temperature state.

  The propulsive force obtained by using the superconducting motor in the propulsion device is much stronger than that obtained by a normal motor, and the size of the superconducting motor can be made much smaller than that of a normal motor. Therefore, the pod type propulsion device employing the superconducting motor can obtain a sufficient propulsive force and can reduce the pod portion to have a small diameter, so that the propulsion efficiency can be increased as much as possible. Further, since the pod type propulsion device is disposed outside the ship, the space in the ship can be used more effectively.

  Furthermore, in order to obtain propulsion using the liquefied natural gas in the tank portion, it is configured to be converted into electrical energy once by the power generator, so that each power generator shares a plurality of power to generate electrical energy. You may have a power generation part. As a result, the size of each power generation unit can be reduced, and sufficient electric energy for driving the superconducting motor can be secured by effectively utilizing the dead space in the ship.

  As described above, according to the cooling system for a superconducting device and the liquefied natural gas tanker of the present invention, it is extremely possible to use some of this liquefied natural gas while securing a sufficient space for the tank of the liquefied natural gas tanker. Efficient driving force can be obtained.

  FIG. 1 is a diagram showing a configuration of a liquefied natural gas tanker 1 according to a first embodiment of the present invention. The liquefied natural gas tanker 1 is liquefied natural gas (LNG: Liquefied Natural Gas). In the following description, it is simply referred to as LNG. ), A power generation device 3 that generates electric energy using natural gas, and a pod type propulsion device 4 that obtains a driving force using the electric energy obtained by the power generation device 3.

  The liquefied natural gas tanker 1 is formed to have a double hull structure, and the tank portion 2 is composed of tank portions 2A and 2B divided into several sections. The tank portion 2A on the bow 1a side is disposed at a position away from the ship bottom 1b. Thereby, even if a problem such as stranded liquefied natural gas tanker 1 occurs, the LNG in the tank portion 2A can be prevented from easily leaking out.

  The power generation device 3 has ten power generation units 3A, 3B,... That generate electric power by sharing about 100 kW of electric energy, and each power generation unit 3A, 3B,. The electric energy of 1M (mega) W is obtained. Each of the power generation units 3A, 3B,... Includes an engine 6 such as a diesel engine that obtains driving force using vaporized LNG and a generator 7 provided on the output drive shaft of the engine 6.

  The pod type propulsion device 4 has a pod main body 4a and a propeller 4b mounted on the lower surface of the stern 1c so as to be rotatable in the horizontal direction, and a superconducting motor 8 (for driving the propeller 4b) in the pod main body 4a. Superconducting equipment) is installed. Since the superconducting motor 8 can obtain a large output, a sufficient propulsive force can be obtained for the liquefied natural gas tanker 1 only by forming the two pod type propulsion devices 4 on the stern 1c. In addition, since the superconducting motor 8 can be easily downsized, the diameter of the pod body 4a that accommodates the superconducting motor 8 can be reduced. That is, if the pod main body 4a becomes thinner, it is possible to obtain a propulsive force efficiently by the propeller 4b.

  In addition, the superconducting motor 8 is cooled by a cooling system 10 for superconducting equipment to a low temperature (for example, 70K or less) that can sufficiently maintain the superconducting state. The winding of the superconducting motor 8 is made of a bismuth-based superconducting material, and this bismuth-based superconducting material enters a superconducting state at 111K. However, by cooling the superconducting motor 8 to 70K or less, its performance is fully exhibited. be able to.

  FIG. 2 is a diagram illustrating the configuration of the cooling system 10 for superconducting equipment. In FIG. 2, reference numeral 11 denotes a cold insulation container filled with liquid nitrogen N as a superconducting cooling medium in a state where the superconducting motor 8 is accommodated, 12 denotes a heat exchanger, 13 controls the heat exchanger 12, A control unit for controlling the temperature of the stored liquid nitrogen N to be 70 K or less, 14 and 15 are temperature sensors for measuring the temperatures in the cold insulation container 11 and the heat exchanger 12, and 16 is supplied to the heat exchanger 12. This is a flow rate control valve that adjusts the flow rate of LNG.

  The cold insulating container 11 includes a heat insulating layer 11a, a bearing 11b that pivotally supports the rotating shaft 8a of the motor 8 and prevents the liquid nitrogen N from leaking outside, and an inlet 11c for the liquid nitrogen N And a nitrogen gas outlet 11d.

  The heat exchanger 12 communicates with the inflow port 11c and the outflow port 11d of the cooling container 11 to circulate nitrogen, and the internal flow channel 12b communicates with the fuel pipe 2a connected to the tank unit 2. And a block body 12c (heat exchange means) made of a metal (for example, aluminum) having excellent thermal conductivity that comes into contact with one surface of the cooling container 11, and a heat insulating layer 12d is formed on the outer peripheral surface thereof. Yes. Further, the internal flow path 12a is formed with a pump 12e as a compression means for raising the temperature of nitrogen by compression, and a throttle portion 12f as a pressure reduction means.

  Since the heat exchanging means 12c of the heat exchanger 12 is a block body 12c made of a metal having excellent heat conductivity as in this embodiment, heat can be efficiently exchanged between fluids flowing through the two internal flow paths 12a and 12b. It can be carried out. Moreover, since the efficiency of heat exchange is good, downsizing can be achieved. Further, since the heat exchanging means 12c of this embodiment is a block body, it is more robust than the heat exchanging means in which piping for flowing nitrogen gas is arranged in a complicated manner, and problems such as gas leakage are unlikely to occur. .

  The controller 13 measures the temperature of the heat exchanging means 12c using the temperature sensor 15, and the temperature of the liquid nitrogen N in the cold container 11 measured using the temperature sensor 14 becomes 70K or less while monitoring this. As described above, control for driving the pump 12e is performed. The controller 13 controls the pump 12e to increase the pressure of the nitrogen gas in the internal flow path 12a, and the temperature of the nitrogen gas increased by pressurization is higher than the temperature immediately after the liquid nitrogen N is vaporized (110K or more). Then, the nitrogen gas heated by the pressurization is cooled by vaporized LNG. Further, the nitrogen gas cooled by LNG is reduced in pressure when passing through the throttle portion 12g, returned to the original pressure again, and returned to the cooling vessel 11 as sufficiently cooled liquid nitrogen N.

  In this way, the control unit 13 drives the pump 12e so that the temperature of the liquid nitrogen N measured by the temperature sensor 14 is about 70K, thereby making the superconducting motor 8 sufficiently more than 111K in which it is in the superconducting state. Can be cooled to a low temperature state (70K or less). That is, the performance of the superconducting motor 8 can be sufficiently improved.

  The flow rate control valve 16 is an electromagnetic valve provided with a flow path opening / closing mechanism for adjusting the flow rate of LNG (or natural gas vaporized by LNG or fluid in a mist state) flowing through the fuel pipe 2a. Depending on the size of the output to be generated, it is appropriately opened and closed. The driving force output from the engine 6 is converted into electric energy by the generator 7 and supplied to the superconducting motor 8. That is, the flow control valve 16 is opened according to the magnitude of the propulsive force required using the pod type propulsion device 4, and the superconducting motor 8 can be cooled according to the flow rate of the fluid passing through the flow control valve 16.

  Therefore, when a larger load is applied to the superconducting motor 8, more powerful cooling can be performed, so that even if some heat is generated due to a large current flowing through the superconducting motor 8, this is sufficiently cooled. can do.

  FIG. 3 is a view showing a modification of the liquefied natural gas tanker 1, and 20 is a cooling of the superconducting equipment used when the generator 7 of the power generating apparatus 3 shown in FIG. 1 is a superconducting generator 21 (superconducting equipment). System. In this modification, the superconducting generator 21 is a superconducting device in which a winding made of, for example, a bismuth-based superconducting material is formed, and is in a superconducting state at a low temperature state of 111 K or less, similar to the superconducting motor 8.

  When such a superconducting generator 21 is used, the cold insulation container 22 has substantially the same structure as the cold insulation container 11 shown in FIG. 2, and the heat exchanger 23 has substantially the same structure as the heat exchanger 12. It is. Moreover, each part 22a-22d which comprises the cold insulation container 22 is the same as each part 11a-11d which comprises the said cold insulation container 11, Each part 23a-23f which comprises the heat exchanger 23 is each part which comprises the said heat exchanger 12 It is the same as 12a-12f. About other points, the detailed description is abbreviate | omitted by making a code | symbol common with FIG.

  That is, the superconducting equipment cooling system 20 shown in this example can keep the superconducting generator 21 at a low temperature by being filled with liquid nitrogen N (an example of a superconducting cooling medium) in a state where the superconducting motor 21 is accommodated. A cold storage container 22 that can be cooled, a compression means 23e that raises the temperature of the vaporized liquid nitrogen N by compressing it, a heat exchange means 23c that cools the heated liquid nitrogen N by a cold heat source of LNG, and Pressure reducing means 23f for reducing the temperature of the liquid nitrogen N by reducing the pressure again.

  As in this example, the generator 7 used in the power generation apparatus 3 is also a superconducting generator 21 and is cooled by the cooling system 20, so that a propelling force can be applied to the liquefied natural gas tanker more efficiently.

  Therefore, as shown in this example, the superconducting equipment cooling system 10 of the present invention can be applied not only to superconducting motors but also to cool superconducting equipment such as superconducting generator 21 and superconducting power storage device (SMES). it can.

  FIG. 4 shows the configuration of the liquefied natural gas tanker 30 according to the second embodiment of the present invention. 4 differs from FIG. 1 in that a power generation device 31 reforms LNG to generate hydrogen gas, and a fuel cell 33 that obtains electric energy using hydrogen obtained by reforming. It is a point. By configuring as in the present embodiment, it is possible to further reduce the size of the power generator 31 and to further secure the space on the ship.

It is a figure which shows the structure of the liquefied natural gas tanker based on 1st Example of this invention. It is a figure which shows the cooling system of the superconducting apparatus used for the said liquefied natural gas tanker. It is a figure which shows the modification of the cooling system of the said superconducting apparatus. It is a figure which shows the structure of the liquefied natural gas tanker based on 2nd Example of this invention. It is a figure which shows the structure of the conventional liquefied natural gas tanker. It is a figure which shows the structure of another conventional liquefied natural gas tanker.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Liquefied natural gas tanker 1b Ship bottom 2 Tank part 3,31 Power generation apparatus 3A, 3B ... Power generation part 4 Pod type propulsion apparatus 8 Superconducting motor 10 Superconducting equipment cooling system N Superconducting cooling medium (liquid nitrogen)

Claims (6)

Superconducting equipment used in propulsion devices for liquefied natural gas tankers that transport liquefied natural gas;
A cooling container capable of keeping the superconducting device in a low temperature state by being filled with a superconducting cooling medium in a state in which the superconducting device is accommodated;
Compression means for heating the vaporized superconducting cooling medium by compressing it,
A heat exchange means for cooling the heated superconducting cooling medium with a cold source of liquefied natural gas;
A cooling system for a superconducting device, comprising: a pressure reducing means for lowering the temperature of the cooled superconducting cooling medium by reducing the pressure. A tank section for storing liquefied natural gas;
A power generation device that generates electric energy using natural gas obtained by vaporizing the liquefied natural gas;
A superconducting motor that obtains driving force using electrical energy, and a propulsion device that obtains propulsive force using the driving force of this superconducting motor, and
A cooling container capable of maintaining the superconducting motor in a low temperature state by being filled with the superconducting cooling medium in a state in which the superconducting motor is accommodated, and compression means for raising the temperature by compressing the vaporized superconducting cooling medium; It has a cooling system comprising a heat exchanging means for cooling a heated superconducting cooling medium with a liquefied natural gas cooling source, and a decompressing means for lowering the temperature of the cooled superconducting cooling medium by reducing the pressure. A liquefied natural gas tanker. A tank section for storing liquefied natural gas;
A superconducting power generation device having a winding made of a superconducting material that generates electric energy using natural gas vaporized from the liquefied natural gas;
A motor that obtains driving force using electric energy, and a propulsion device that obtains driving force using the driving force of the motor; and
A cooling container capable of maintaining the superconducting power generation device in a low temperature state by being filled with the superconducting cooling medium in a state in which the superconducting power generation device is accommodated, and a compression means for raising the temperature by compressing the vaporized superconducting cooling medium. And a heat exchanging means for cooling the heated superconducting cooling medium with a liquefied natural gas cooling source, and a depressurizing means for lowering the temperature by depressurizing the cooled superconducting cooling medium. A featured liquefied natural gas tanker.   The liquefied natural gas tanker according to claim 2 or 3, wherein the propulsion device is a pod type propulsion device.   The liquefied natural gas tanker according to claim 4, wherein the tank part is disposed at a position away from the ship bottom by a double hull structure.   The liquefied natural gas tanker according to any one of claims 2 to 5, further comprising a plurality of power generation units that each share the power generation device to generate electrical energy.

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