KR20130065184A - Liquefied gas carrier - Google Patents

Abstract

PURPOSE: A liquefied gas carrier is provided to implement thermoelectric generation using temperature difference between the inside and outside of an insulation plate by installing both ends of a thermocouple to the inside and outside of the insulation plate. CONSTITUTION: A liquefied gas carrier comprises a cargo hold and a thermoelectric generator(150). The cargo hold comprises a storage tank(130) for storing liquefied gas and a gas pipe(140) by which the liquefied gas is introduced into or discharged from the storage tank. The thermoelectric generator is installed in the cargo hold to generate electricity using temperature difference generated by the liquefied gas. The storage tank comprises an inner wall(131) directly contacted to the liquefied gas and an insulation plate installed to surround the inner wall. The thermoelectric generator comprises a thermocouple and a capacitor(156).

Description

Liquefied Gas Carrier {LIQUEFIED GAS CARRIER}

The present invention relates to a liquefied gas carrier ship including a thermoelectric generator.

Natural gas, which contains methane as its main component, has almost no pollutants and is excellent in calories and has emerged as an important energy source. When natural gas is liquefied, its volume decreases, making mass transportation easier. Therefore, natural gas is mainly transported in the form of liquefied natural gas (LNG). Accordingly, the demand for liquefied natural gas carriers has recently increased rapidly. have.

Cargo tanks of LNG carriers are designed with an insulating structure that thermally separates the interior and exterior to keep the natural gas in the liquid phase and protect the hull from the cold air. Therefore, a large temperature gradient is generated inside and outside the cargo hold by the ultra low temperature liquefied natural gas. Currently, thermal energy according to such a temperature gradient is discarded uselessly.

Korean Patent Publication No. 10-2009-0106161

Embodiments of the present invention are intended for thermoelectric power generation using a temperature difference generated by liquefied gas in a liquefied gas carrier.

According to an aspect of the present invention, a liquefied gas carrier ship cargo tank including a storage tank in which liquefied gas is stored and a gas pipe in which the liquefied gas is introduced or discharged to the storage tank; And a thermoelectric generator installed in the cargo hold and generating power using a temperature difference generated by the liquefied gas.

The storage tank may include an inner wall directly contacting the liquefied gas and a heat insulating plate disposed to surround the inner wall. The thermoelectric generator may have one end located inside the heat insulating plate and the other end outside the heat insulating plate. By using a temperature difference between the inside and outside of the insulation plate may include a thermocouple for generating electrical energy and a capacitor for storing the generated electrical energy.

The cargo hold may further include a fixing member for fixing the inner wall and the heat insulating plate to each other, and one end of the thermocouple may be installed at the fixing member.

The thermocouple may include a terminal ring fitted to the fixing member and a pair of thermocouple wires connected to the terminal ring.

The thermoelectric generator may include a thermocouple having one end installed in the gas pipe and a capacitor storing electrical energy generated by the thermocouple.

The ship may further include a hull in which the cargo hold is stored. The other end of the thermocouple may be installed on the hull.

Embodiments of the present invention can be thermoelectric power generation using the temperature difference between the inside and outside of the heat insulating plate by installing both ends of the thermocouple inside and outside the heat insulating plate of the storage tank.

In addition, embodiments of the present invention can be thermoelectric power generation by installing a thermocouple in the gas pipe of the cargo hold.

1 is a cross-sectional view of an embodiment of a liquefied gas carrier ship according to an embodiment of the present invention.
FIG. 2 is a diagram illustrating an embodiment of a coupling relationship between an inner wall and a heat insulating layer of the storage tank of FIG. 1.
3 is a view showing another embodiment of the coupling relationship between the inner wall and the heat insulating layer of the storage tank of FIG.
4 is a conceptual diagram of the thermoelectric generator of FIG. 1.
5 is a temperature-electromotive force graph of a thermocouple.
6 is a perspective view of the power generation unit of FIG. 4.
7 is a view illustrating that the power generation unit of FIG. 6 is installed in the fixing member.
8 is a view showing that the power generation unit of FIG. 6 is installed in a gas pipe.
9 is a diagram illustrating a plurality of power generation units of FIG. 6 installed.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to be illustrative of the present invention and not to limit the scope of the invention. Should be interpreted to include modifications or variations that do not depart from the spirit of the invention.

The terms used in the present specification and the accompanying drawings are for easily explaining the present invention, and the shapes shown in the drawings are exaggerated and displayed to help understanding of the present invention as necessary, and thus, the present invention is used herein. It is not limited by the terms and the accompanying drawings.

In the present specification, when it is determined that a detailed description of a known configuration or function related to the present invention may obscure the gist of the present invention, a detailed description thereof will be omitted as necessary.

Hereinafter, a liquefied gas carrier ship 100 according to an embodiment of the present invention will be described. The liquefied gas carrier 100 stores and transports the fluid in a cryogenic liquid state. The liquefied gas carrier 100 may be a liquefied natural gas carrier (LNGC) for transporting liquefied natural gas. Of course, the liquefied gas carrier 100 according to the embodiment of the present invention is not limited to the liquefied natural gas carrier. For example, the liquefied gas carrier 100 is provided with a thermal insulation layer 133 having a predetermined physical and chemical properties in the cargo hold 120, in addition to the liquefied natural gas in the internal space, liquefied ammonia, liquefied petroleum gas (LPG) , Ethylene, crude oil, etc. may be a vessel for storing and transporting as a cryogenic liquid.

Hereinafter, with reference to an embodiment of the liquefied natural gas carriers for transporting liquefied natural gas with respect to an embodiment of the liquefied natural gas carriers 100 according to the present invention. However, since this is only for ease of explanation, the present embodiment may be applied to the other liquefied gas carrier ship 100 described above.

1 is a cross-sectional view of an embodiment of a liquefied gas carrier ship 100.

Referring to FIG. 1, the liquefied gas carrier ship 100 includes a hull 110, a cargo hold 120, and a thermoelectric generator 150. The hull 110 forms the outer wall of the liquefied gas carrier ship 100, the cargo hold 120 is installed inside the hull 110 to store the liquefied natural gas. The thermoelectric generator 150 is installed in the cargo hold 120 to generate power by using a temperature difference generated by liquefied natural gas.

The hull 110 provides a space in which other components are installed. The hull 110 is provided in a watertight structure so that the inside of the ship is not flooded. For example, the hull 110 may be provided in a dual structure of an outer hull 111 and an inner hull 112. The hull 110 and the cargo hold 120 are spaced apart from each other, and the cargo hold 120 has thermal insulation, so the hull 110 is maintained at room temperature. Moreover, the hull 110 is in direct contact with the sea water and thus can be maintained at the temperature of the sea water.

The cargo hold 120 is installed inside the hull 110. The cargo hold 120 may be spaced apart from the hull 110 and installed inside the hull 110. For example, a support chuck 115 may be disposed on a wall surface of the hull 110, and the cargo hold 120 may be supported by the support chuck 115 and installed inside the hull 110. Here, the hull 110 and the cargo hold 120 may be fixed to each other by a fixing means such as a stud bolt (not shown).

The cargo hold 120 may include a storage tank 130 and a gas pipe 140. The liquefied gas is stored in the storage tank 130, and the gas pipe 140 is connected to the storage tank 130 to supply the liquefied gas to the storage tank 130 or to discharge the liquefied gas from the storage tank 130.

FIG. 2 is a diagram illustrating an embodiment of a coupling relationship between an inner wall 131 and a heat insulating layer 133 of the storage tank 130 of FIG. 1.

Referring to FIG. 2, the storage tank 130 includes an inner wall 131, a heat insulation layer 133, and a fixing member 136. The inner wall 131 directly contacts the liquefied natural gas, and the heat insulation layer 133 is installed to surround the inner wall 131 to insulate the liquefied natural gas. The fixing member 136 fixes the inner wall 131 and the heat insulation layer 133 to each other.

The inner wall 131 is provided of a material that can withstand ultra low temperatures. In the storage tank 130, since the natural gas of the liquid phase is stored with a vapor pressure higher than atmospheric pressure in an ultra low temperature state of -163 ° C or lower, the inner wall 131 which receives the direct contact with it has low temperature resistance. It is excellent, prevents heat intrusion, and is made of a material resistant to thermal stress and heat shrinkage. For example, the inner wall 131 may be made of a material such as aluminum steel, stainless steel, 36% nickel steel, or the like.

The inner wall 131 may be formed with a protrusion 132 bent to protrude into the storage tank 130. The inner wall 131 may perform thermal contraction or thermal expansion because the temperature varies in a wide range from room temperature to -163 ° C. or less in which the liquefied natural gas is stored in the storage tank 130 while the storage tank 130 is empty. The bent protrusion 132 may provide a space in which the inner wall 131 may be deformed, thereby preventing the inner wall 131 from being damaged due to thermal deformation.

The heat insulation layer 133 is comprised by the heat insulation board 134 which has heat insulation. As the heat insulation plate 134, a heat insulation panel made of polyurethane foam (R-PUF) may be used. In FIG. 2, the heat insulation layer 133 is provided by connecting the heat insulation plate 134 as one layer, but in some cases, the heat insulation layer 133 may be formed by cross-gluing the heat insulation plate 134 in several layers.

The heat insulation layer 133 is installed outside the inner wall 131 to surround the inner wall 131. Accordingly, the cold air of the liquefied natural gas stored inside the inner wall 131 is blocked from being transferred to the outside, and a temperature difference occurs inside and outside the heat insulating layer 133.

The fixing member 136 fixes the inner wall 131 and the heat insulation layer 133 to each other. In this case, a predetermined space may be provided between the inner wall 131 and the heat insulation layer 133 to improve the heat insulation efficiency. This space can be filled with carbon dioxide or vacuumed.

The stud bolt 136 may be used as the fixing member 136. Hereinafter, the fixing member 136 will be described based on the stud bolt 136. However, this is only for ease of description, and as the fixing member 136, various fixing means including an anchor or a fastener may be used in addition to the stud bolt 136.

Stud bolt 136 includes a screw 137 and a nut 138.

The screw 137 is attached to the outer side of the inner wall 131. The screw 137 may be attached in advance before the heat insulation layer 133 is installed on the outside of the inner wall 131. The screw 137 may be attached to the outside of the inner wall 131 by an arc welding method such as stud welding.

Specifically, the stud welding is performed between the outer surface of the inner wall 131 and the screw 137 by a welding torch or a welding gun while the screw 137 is in contact with the outer surface of the inner wall 131. This is done by generating an arc. When an arc is generated, the outer surface of the inner wall 131 and the screw 137 are locally melted to form a weld bead around the screw 137 to be in close contact with the outside of the inner wall 131 and welded. Compared with other welding methods, stud welding has the advantages of easy welding, low welding deformation, wide range of weldable materials, and fast welding without the need for a separate hole in the base material.

The screw 137 attached to the outer surface of the inner wall 131 is inserted into the fastening hole 135 formed in the heat insulation layer 133. The fastening hole 135 is formed inside the heat insulation layer 133 so that the screw 137 of the stud bolt 136 penetrates and is inserted therein. The nut 138 is fastened to the portion where the screw 137 is inserted to fix the inner wall 131 and the heat insulation layer 133. The fastening hole 135 is sealed by injecting a sealing material having excellent heat insulating properties.

3 is a view showing another embodiment of the coupling relationship between the inner wall 131 and the heat insulating layer 133 of the storage tank 130 of FIG.

Although the thickness of the heat insulating layer 133 is greater than the length of the screw 137 in FIG. 2, the stud bolt 136 does not penetrate the heat insulating layer 133, but as shown in FIG. 3, the screw 137 is shown. It is also possible to provide a sufficiently long length of the stud bolt 136 to penetrate to the opposite side of the heat insulating layer 133. In this case, the cross section of the fastening hole 135 may be formed in the same manner as the cross section of the screw 137 to prevent the leakage of cold air from the inside without a separate sealing material.

The gas pipe 140 is connected to one side of the storage tank 130 to supply a liquefied natural gas to the storage tank 130 or to provide a passage through which the liquefied natural gas is discharged from the storage tank 130. Referring back to FIG. 1, the gas pipe 140 may be formed above the storage tank 130. Since the structure of the gas pipe 140 may be provided to have an inner tube 141 and a heat insulating layer 142 similar to the storage tank 130, a detailed description thereof will be omitted.

4 is a conceptual diagram of the thermoelectric generator 150 of FIG. 1, and FIG. 5 is a temperature-electromotive force graph of the thermocouple 152.

The thermoelectric generator 150 includes a power generation unit 151 and a capacitor 156. The power generation unit 151 performs power generation using a temperature difference generated by liquefied natural gas, and the capacitor 156 stores the electric energy generated by the power generation unit 151.

The power generation unit 151 generates electric energy by the thermoelectric effect, that is, the principle of the Seebeck effect. The thermoelectric effect means a phenomenon in which an electromotive force is generated due to the temperature difference and an electric current flows when a temperature difference is applied to both ends of the thermocouple 152 connecting metals or semiconductors of different materials. As shown in FIG. 5, a relatively hot end of both ends of the thermocouple 152 becomes a hot junction, and a relatively low end of the thermocouple 152 becomes a cold junction, in the thermocouple 152. The magnitude of the generated electromotive force is roughly proportional to the temperature difference between the hot and cold junctions.

The thermocouple 152 uses the inside of the heat insulating layer 133 as a cold junction, and uses the outside of the heat insulating layer 133 as a hot contact to generate electricity by using a temperature difference inside and outside the heat insulating layer 133. Here, a space or a support chuck 115 or the like between the hull 110 or the hull 110 and the heat insulating layer 133 may be used as the hot contact point, and there is no particular limitation.

Since the inside of the heat insulation layer 133 is maintained at about -163 ° C by the liquefied natural gas, and the outside is maintained at about room temperature at about 25 ° C, the thermocouple 152 generates electric energy using a large temperature difference of about 190 ° C. can do.

The thermocouple 152 may be provided in various ways depending on the type of metal used. For example, the thermocouple 152 may be E type composed of chromel-constantan or J type composed of iron-constantan. Of course, the type of the thermocouple 152 is not limited to the above-described example, the thermocouple 152 may be appropriately selected in consideration of various factors such as power generation efficiency, price, durability, stability, installation ease.

The power generation unit 151 may include a thermocouple 152 and a terminal ring 155.

6 is a perspective view of the power generation unit 151 of FIG. 4, and FIG. 7 is a view illustrating that the power generation unit 151 of FIG. 6 is installed in the fixing member 136.

The terminal ring 155 is attached to the fixing member 136 is installed. The terminal ring 155 may be provided to have a circular ring-shaped cross section to be fitted to the stud bolt 136. The inner diameter of the terminal ring 155 is provided to be similar to the outer diameter of the stud bolt 136. Since the terminal ring 155 directly contacts the stud bolt 136 of ultra low temperature, the terminal ring 155 may be provided with a material having strong low temperature resistance.

The thermocouple 152 may be provided in a wire type in the form of a metal wire. The wire type thermocouple 152 is simple to mount one end inside the heat insulation layer 133 as compared to semiconductors or other types, and has an advantage of easy maintenance.

The thermocouple 152 provided as a wire type includes a first thermoelectric wire 153 and a second thermoelectric wire 154. The first thermoelectric wire 153 and the second thermoelectric wire 154 are made of metal of different materials. For example, as described above, the first thermoelectric wire 153 may be made of steel, and the second thermoelectric wire 154 may be made of constantan.

One end of each of the first thermoelectric wire 153 and the second thermoelectric wire 154 may be connected to the terminal ring 155. The terminal ring 155 is inserted into the study bolt 136 so that the cool air of the liquefied natural gas is connected to the first thermoelectric wire 153 and the second thermoelectric wire through the inner wall 131, the study bolt 136, and the terminal ring 155. Each end of 154 is passed. Thus, each end connected to the terminal ring 155 becomes a cold junction of the thermocouple 152.

In addition, the other ends of the first thermoelectric wire 153 and the second thermoelectric wire 154 may be located outside the heat insulation layer 133. For example, the other ends of the first thermoelectric wire 153 and the second thermoelectric wire 154 may be attached to the hull 110 or the space between the hull 110 and the heat insulation layer 133 or the support chuck 115. Can be. The outside of the heat insulating layer 133 is maintained at room temperature to serve as a hot contact.

On the other hand, the position of the cold junction and the hot junction of the thermocouple 152 is not necessarily limited to the above-described example.

For example, the thermocouple 152 is provided in a structure in which the terminal ring 155 is omitted, and one end of the pair of thermocouple wires 153 and 154 is attached to the study bolt 136 without passing through the terminal ring 155 or It may also be attached directly to the outer surface of the inner wall (131). In another example, the other end of the pair of thermoelectric wires 153, 154 may be located outside the insulation layer 133, including the void space between the hull 110 and the insulation layer 133 in addition to the hull 110, or may be directly connected to the capacitor 156. It may be.

For another example, the thermocouple 152 may be installed in the gas pipe 140, not the storage tank 130.

8 is a view illustrating that the power generation unit of FIG. 6 is installed in the gas pipe 140. The gas pipe 140 also has an inner tube 141 and a heat insulating layer 142 like the storage tank 130, one end of the thermocouple 152 is located inside the heat insulating layer 142, and the other end is outside the heat insulating layer 142. By being located at, the electrical energy can be generated using the temperature difference.

The capacitor 156 stores the electric energy generated by the power generation unit 151. Referring back to FIG. 4, the capacitor 156 is connected to the power generation unit 151 to store electricity generated by the power generation unit 151.

9 is a diagram illustrating that a plurality of power generation units 151 of FIG. 6 are installed.

Referring to FIG. 9, a plurality of thermoelectric generators 150 may be installed at various portions of the storage tank 130 or the gas pipe 140. Such a plurality of thermoelectric generators 150 may be connected to the capacitor 156, respectively. Electrical energy generated by the thermoelectric generator 150 may be stored in the capacitor 156.

Here, the thermocouple 152 may be installed in the gas pipe 140 as well as the bottom, side, top of the storage tank 130. In addition, the thermocouple 152 may be installed without limitation by using a cold junction as a portion maintained at low temperature due to liquefied natural gas.

Since the liquefied gas carrier ship 100 may self-produce electrical energy through the thermoelectric generator 150 by using a temperature difference between the inside and the outside of the heat insulation layer 133 generated by the liquefied gas stored in the storage tank 130, It can be used effectively by recycling the heat energy which is not used and consumed.

On the other hand, the above-described storage tank 130 and the thermoelectric generator 150 may be used in various ways in addition to the liquefied gas carrier (100). For example, a thermoelectric power generation facility including the storage tank 130 and the thermoelectric generator 150 described above may be installed in another liquefied gas transportation means such as a liquefied gas storage or an automobile or a train to perform thermoelectric power generation. will be.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to be illustrative of the present invention and not to limit the scope of the invention. Should be interpreted to include modifications or variations that do not depart from the spirit of the invention.

100: liquefied gas carrier 110: hull 111: outer body
112: internal 115: support chuck 120: cargo hold
130: storage tank 131: inner wall 132: protrusion
133: heat insulation layer 134: heat insulation plate 135: fastening hole
136: fixing member, stud bolt 137: screw
138: nut 140: gas pipe 141: inner pipe
142: insulation layer 150: thermoelectric generator 151: power generation unit
152: thermocouple 153: first thermoelectric wire 154: second thermoelectric wire
155: terminal ring 156: capacitor

Claims (6)

A cargo tank including a storage tank in which liquefied gas is stored and a gas pipe through which the liquefied gas is introduced or discharged into the storage tank; And
A thermoelectric generator installed in the cargo hold and generating power using a temperature difference generated by the liquefied gas;
Liquefied gas carriers. The method of claim 1,
The storage tank includes an inner wall which is in direct contact with the liquefied gas and a heat insulating plate installed to surround the inner wall,
The thermoelectric generator may include a thermocouple having one end positioned inside the insulation plate and the other end positioned outside the insulation plate to generate electrical energy using a temperature difference inside and outside the insulation plate, and a capacitor for storing the generated electrical energy.
Liquefied gas carriers. The method of claim 2,
The cargo hold further comprises a fixing member for fixing the inner wall and the heat insulating plate to each other,
One end of the thermocouple is installed on the fixing member
Liquefied gas carriers. The method of claim 3,
The thermocouple includes a terminal ring fitted to the fixing member and a pair of thermocouple wires connected to the terminal ring.
Liquefied gas carriers. The method of claim 1,
The thermoelectric generator may include a thermocouple having one end installed in the gas pipe and a capacitor storing electrical energy generated by the thermocouple.
Liquefied gas carriers. 6. The method according to any one of claims 2 to 5,
Further comprising a; a hull in which the cargo hold is accommodated;
The other end of the thermocouple is provided on the hull
Liquefied gas carriers.

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