JP2654326B2 - Cryogenic thermal power generation equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cryogenic power generation device using cryogenic material, and more particularly to a power generation device using cryogenic heat in an underground tank or the like for storing cryogenic material such as LNG.

[0002]

2. Description of the Related Art A cryogenic substance such as LNG, which is a liquefied natural gas, is stored at, for example, about -160 ° C. and retains a large amount of cold. On the other hand, attempts have been made to effectively utilize the cold heat of the cryogenic substance by air liquefaction separation and cryogenic storage. On the other hand, in an underground tank or the like that stores a cryogenic substance, there is a problem that the ground around the storage tank freezes due to cold heat. In order to prevent ground freezing, as shown in FIG. 4, a ground heat insulating structure such as a continuous wall 4 including a heat source 5 such as a heat fence or a hot water heater is provided outside the heat insulating wall 3 of the storage tank 2.

[0003]

However, of the thermal energy supplied from the heat source 5 to the continuous wall 4 in the above-mentioned ground thermal insulation structure, the heat transmitted from the outside of the continuous wall 4 to the surrounding ground 8 is used for the purpose of keeping the ground warm. Although it is used effectively, the heat transmitted from the inside of the continuous wall 4 to the heat insulating wall 3 of the low-temperature storage tank is not effectively used. In addition, conventional methods such as air liquefaction separation and cryogenic storage that use the cold heat of cryogenic substances are not easy to implement because all require large-scale and complicated facilities.

[0004] It is therefore an object of the present invention to store cryogenic substances.
Reduces external energy required to keep the ground around the tank warm
In

[0005]

Means for Solving the Problems In order to realize the above object, the present inventor paid attention to the Beheck effect by a thermocouple. The thermocouple 10 is, for example, as shown in FIG.
11 and a p-type thermoelectric element 12. One end 13 of each thermoelectric element 11, 12 is connected, and the other end 19 of each thermoelectric element 11, 12 is connected to an output terminal 17.
And the other end of each thermoelectric element 11, 12
19 was kept at the same temperature. In the figure, the dotted frame indicates that the two other ends 19 are kept at the same temperature. One end 13 and the other end 19 to be the connecting portions of the different thermoelectric elements 11 and 12 of the thermocouple 10
Are maintained at different temperatures T1 and T2, respectively, an electromotive force V is generated at the two output terminals 17 due to the Besek effect. If this principle of a thermocouple is used, the cold heat of the cryogenic substance can be recovered as electric energy.

Referring to the embodiments shown in FIGS. 1, 4 and 5 , a cryogenic substance cold heat power generating apparatus 9 according to the present invention comprises a cryogenic substance 1 provided with a continuous wall 4 having a heat source 5 outside a heat insulating wall 3. In the storage tank 2, the isotherm near the outer surface of the heat insulating wall 3 is the most
In a dense part, a slit formed long parallel to the isotherm
A plurality of thermocouples 10 are inserted into the thermocouple 10, and one end 13 (or 19 ) and the other end 19 (or
3) on the opposite surface of the slit parallel to the isotherm
Re which electrically contacted by insulation, formed by connecting the end of the output terminal 17 which electromotive force is generated in each thermocouple 10 (FIG. 5 (C))
It is .

[0007] The continuous wall 4 in the present invention means a wall connected to the outside of the heat insulating wall 3 and including a heat source 5 for keeping the ground warm. When the heat source 5 is embedded in the heat insulating wall 3 as shown in FIG. 1B, the portion of the heat insulating wall 3 including the heat source 5 corresponds to the continuous wall 4. The imaginary line II in the drawing means that the outside of the imaginary line II as viewed from the inside of the storage tank 2 is regarded as the continuous wall 4.

In the embodiment of the power generating device 9 shown in FIG. 1, for example, at least one of the heat insulating wall 3 and the continuous wall 4 is provided with a slit having a gap corresponding to the length between both ends of the thermocouple 10, and the thermocouple 10
Into the slit. Storage tank 2 from the design stage
When the power generation device 9 is included in the storage tank 2, a thermocouple 10 is previously attached to the surface of the side wall or the bottom wall constituting the heat insulating wall 3 of the storage tank 2 so that optimum power generation can be performed.

Preferably, as shown in the embodiment of FIGS. 2 and 5 , a module 20 comprising a plurality of
And one end 13 and the other end 19 of each thermocouple 10.
Are electrically insulated and in contact with the opposing surface of one protective plate 16 and the opposing surface of the other protective plate 16, respectively.
And the other protective plate 16 is brought into contact with the outer surface of the heat insulating wall 3 and the inner surface of the continuous wall 4, respectively. One end 13 of each thermocouple 10
(Or 19 ) and the other end 19 (or 13) are in contact with the outer surface of the heat insulating wall 3 and the inner surface of the continuous wall 4 via the protective plate 16, respectively. The protection plate 16 may be, for example, a ceramic plate and has a mechanical strength to protect the thermocouple 10. More preferably, the thermocouple 10 is made of a bismuth-tellurium-based thermoelectric material.

[0010]

FIG. 4 shows an example of the temperature distribution of the heat insulating wall 3 in the storage tank 2 for the cryogenic substance 1. FIG. 4A shows a temperature distribution in a cross section perpendicular to the bottom surface, and FIG. 4B shows a heat distribution wall 3 in a cross section parallel to the bottom surface and a temperature distribution on the outside thereof. In the case of the illustrated example, the inside of the heat insulating wall 3 close to the cryogenic substance 1 is kept at about −25 ° C. to −40 ° C. by the cold heat of the cryogenic substance 1, and outside the heat insulating wall 3 facing the continuous wall 4. It becomes approximately −0 ° C. due to the heat supplied from the heat source 5, and it can be seen that the isothermal lines are arranged closely at intervals. On the other hand, in the continuous wall 4, the interval between the isotherms becomes wider, and the surrounding ground 8 becomes 8 ° C.
It is kept warm to the extent.

The power generator 9 of the present invention is inserted between the heat insulating wall 3 and the continuous wall 4 in which isothermal lines are densely arranged, and the heat insulating wall 3 of each thermocouple 10 is provided.
One end 13 (or 19 ) contacting the outer surface of the wall is cooled by the cold heat of the cryogenic substance 1 and the other end contacting the inner surface of the continuous wall 4.
19 (or 13) becomes relatively high temperature due to the heat of the heat source 5. Since the two ends of the different thermoelectric elements, which are the connecting portions, are maintained at different temperatures, an electromotive force is generated in the thermocouples 10, and the electromotive force generated in each thermocouple 10 can be taken out through the output terminal 17.

As shown in FIG. 4, the temperature of the outer wall of the heat insulating wall 3 is-
When the temperature is approximately 0 ° C., a bismuth-tellurium-based thermoelectric material having a maximum thermoelectric conversion efficiency near room temperature can be used as the thermocouple 10 of the present invention. However, the thermocouple of the present invention
10 is not limited to this, and other thermoelectric materials that can be used near normal temperature, and further, when the outer wall temperature of the heat insulating wall 3 is not normal temperature, a thermoelectric material corresponding to the temperature can be used.

For example, when the heat source 5 is provided near the inner surface of the continuous wall 4, one end of the thermocouple can be maintained at a temperature close to the operating temperature of the heat source 5. That is, when the operating temperature of the heat source 5 is about 20 ° C., the temperature difference between both ends of the thermocouple 10 can be made about 30 ° C. According to the estimation of the present inventor, when the temperature difference between both ends is 30 ° C., power of 0.018 W / cm ² is obtained, and when the thermocouple 10 is spread over 1 m ² , 18
0W output can be obtained.

The power generation device 9 of the present invention comprises the heat insulating wall 3 and the continuous wall 4.
It is a simple structure with a thermocouple 10 inserted between
Moreover, it is possible to easily use the cold heat of the cryogenic substance. Therefore, the object of the present invention is to provide a "power generator having a simple structure using cold heat of a cryogenic substance".

[0015]

As shown in FIG. 5B, one end of an n-type thermoelectric element 11 and one end of a p-type thermoelectric element 12 are connected by a conductive coupling electrode 14 to form one end 13 of a thermocouple. One end 13 of (A)
It has been experimentally confirmed that it functions similarly to. FIG.
A plurality of thermocouples 10 of (B) are arranged in a predetermined planar shape to form a thermocouple module 20 shown in FIG. 5 (C), and the power generating device 9 of the present invention is manufactured using the module. Can be.

In the embodiment of FIG. 2, for example, a plurality of thermocouples 10 in the form of a module 20 are sandwiched between two opposing protective plates 16, and one end of each thermocouple 10 to be a connecting portion of a different thermoelectric element and another The end is the opposite surface of one protection plate 16 and the other protection plate
16 shows a power generation unit 18 having an output terminal 17 connected to an end of each thermocouple 10 where an electromotive force is generated, each of which is electrically insulated and in contact with the opposite surface of the thermocouple 16. Power generation unit 18 is several tens of cm
The size can be several m from the corner, and the size is selected according to the area of the heat insulating wall 3 used for power generation, the amount of energy to be recovered, and the like, and the power generation device 9 is assembled by combining the sizes.
The shape is not limited to the flat plate shape in the illustrated example, but may be any shape that fits on the outer surface of the heat insulating wall 3. Preferably, the thermocouple 10 of the power generation unit 18 is made of a bismuth-tellurium-based thermoelectric material.

In the embodiment shown in FIG. 3, a heat insulating device 6 is brought into contact with the inner surface of the continuous wall 4, and the heat insulating device 6 is opposed to the outer surface of the heat insulating wall 3 via a gap. A power generator 9 according to the present invention, in which one end and the other end of the thermocouple 10 to be connected to the different thermoelectric elements are electrically insulated and contact with the outer surface of the heat insulating wall 3 and the heat retaining device 6, respectively. Is shown. Preferably, a plurality of thermocouples 10 are arranged so as to be sandwiched between two facing protection plates 16. The heat retaining device 6 in the illustrated example includes a box 23 in contact with the inner surface of the continuous wall 4, and internal circulating means 24 for taking in hot water 21 from the outside into the box 23, circulating the inside, and sending it out to the outside. The heat of the hot water 21 is supplied to the continuous wall 4 and the power generator 9 through the 23 walls. A heat fence or the like may be used as the heat retaining device 6. Since the heat of the heat retaining device 6 is transmitted to the thermocouple 10 without passing through the continuous wall 4, a large temperature difference between both ends of the thermocouple 10 can be maintained, and efficient power generation can be expected. Further, the power generation device 9 shown in FIG. 3 can be assembled using the power generation unit 18 shown in FIG.

[0018]

As described above in detail, the cryogenic substance cold energy power generating apparatus according to the present invention comprises a plurality of thermocouples each comprising the outer surface of the heat insulating wall of the cryogenic substance storage tank and the ground heat insulating heat source opposed thereto. Since it is configured to be inserted between the inner surface of the connecting wall and the connecting wall, the following remarkable effects are exhibited. (1) With a simple configuration, it is possible to extract electric energy by using cold heat held by the cryogenic substance 1. (2) By adding all or a part of the generated energy to the heat source of the continuous wall in the ground thermal insulation structure including the continuous wall, it is possible to reduce the amount of heat supplied from the outside to the ground thermal insulation structure.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of one embodiment of the present invention.

FIG. 2 is an explanatory diagram of a power generation unit of the present invention.

FIG. 3 is an explanatory diagram of another embodiment of the present invention.

FIG. 4 is a temperature distribution diagram of a cryogenic substance storage tank.

FIG. 5 is an explanatory diagram of a thermocouple according to the present invention.

[Explanation of symbols]

1 Cryogenic substance 2 Storage tank 3
Insulated wall 4 Connecting wall 5 Heat source for keeping the ground warm 6
Heat insulation device 8 Ground 9 Power generation device 10
Thermocouple 11 N-type thermoelectric element 12 P-type thermoelectric element 13
One end 14 Coupling electrode 15 Connection electrode 16
Protection plate 17 Output terminal 18 Power generation unit 19
Other end 20 Thermocouple module 21 Hot water 23
Box 24 Hot water circulation means.

Claims (6)

(57) [Claims] 1. A storage tank for a cryogenic substance having a continuous wall with a heat source provided outside a heat insulating wall, the tank being near an outer surface of the heat insulating wall.
In the area where the next isotherm is the densest, extend parallel to the isotherm
A plurality of thermocouples are inserted into the formed slit, and one end and the other end of each thermocouple, which are to be joined portions of the different types of thermoelectric elements, are described above.
A cryogenic thermal power generation apparatus using a cryogenic substance, wherein an end of each of the thermocouples where an electromotive force is generated is connected to an output terminal, each of the slits being electrically insulated and in contact with a facing surface of the slit parallel to the isotherm . 2. The power generator according to claim 1, wherein a heat insulating device is provided on an inner surface of the connecting wall, and the heat insulating device is opposed to an outer surface of the heat insulating wall via a gap.
A cryogenic substance comprising a plurality of thermocouples arranged as slits and one end and the other end of each thermocouple electrically insulated and in contact with the outer surface of the heat insulating wall and the heat retaining device, respectively. Power generation equipment using cold energy. 3. The power generator according to claim 1, wherein the plurality of thermocouples are sandwiched between two opposing insulating ceramic protection plates, and one end and the other end of each thermocouple are connected to one of the protection plates. The opposite surface and the opposite surface of the other protection plate are respectively electrically insulated and contacted, and the one protection plate and the other protection plate are respectively brought into contact with the outer surface of the heat insulating wall and the inner surface of the continuous wall, respectively. Cryogenic thermal power generation equipment. 4. The power generator according to claim 1, wherein the thermocouple is made of a bismuth-tellurium-based thermoelectric material. 5. A plurality of thermocouples facing two insulating cells.
Was sandwiched between ceramic protective plate, respectively electricity opposing surface of the opposing surfaces and the other of the protective plate of one of the insulating ceramic coercive <br/> Mamoruban the coupling portion serving to one end and the other end of the heterologous thermoelectric elements of each thermocouple The power generation unit for a power generation device according to claim 2 or 3, further comprising an output terminal that is electrically insulated and in contact with each other, and is connected to an end where an electromotive force of each thermocouple is generated. 6. The power generation unit according to claim 5, wherein said thermocouple is made of a bismuth-tellurium-based thermoelectric material.