KR20190041859A - Reliquefaction apparatus of liquified gas using fuel LNG and liquefied gas carrier having the same - Google Patents

Abstract

The present invention relates to a liquefied gas reliquefying apparatus using LNG fuel and a liquefied gas carrier having the same, and specifically, to a liquefied gas reliquefying apparatus using LNG and a liquefied gas carrier having the same, capable of reducing costs required for installation and operation of the reliquefying apparatus of the liquefied gas carrier. According to the present invention, the liquefied gas reliquefying apparatus using LNG fuel and the liquefied gas carrier having the same are possible to reduce costs of the reliquefying apparatus of the liquefied gas carrier and operation costs by using cold heat of LNG fuel to reliquefy boil off gas of liquefied gas, and improve economical efficiency in accordance with use of LNG fuel by utilizing LNG fuel as liquefied gas reliquefaction to reduce additional costs.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a liquefied gas re-liquefaction apparatus using LNG fuel and a liquefied gas carrier having the liquefied gas carrier having the same.

The present invention relates to a liquefied gas re-liquefying apparatus using LNG fuel and a liquefied gas carrier having the same, and more particularly, to a liquefied gas re-liquefying apparatus using LNG fuel, which is configured to reduce the cost of installation and operation of a liquefied gas carrier re- And a liquefied gas carrier having the same.

The demand for reduction of SOx, NOx and CO2 generated during the operation of ships is increasing internationally. As the price of oil increases, the ship which can reduce the operation cost of the ship by using LNG instead of the existing oil as propellant is developed . However, ships using liquefied gas as fuel require additional tanks for storing the liquefied gas fuel and separate devices for supplying the liquefied gas, which increases the cost of building the ship, which hinders commercialization of the liquefied gas as fuel for the ship .

In order to reduce the volume of the fuel tank, a ship using LNG as propellant fuel stores the fuel as LNG, which is a liquefied natural gas, and vaporizes the LNG before it is used as fuel. .

On the other hand, a liquefied gas carrier such as an LPG carrier, a CO2 carrier, and an Ethane carrier may increase the pressure in the liquefied gas tank due to external heat input during operation. As one of the methods for controlling the liquefied gas carrier, Liquid remover for re-liquefying the liquid. However, such a liquefaction apparatus has a problem that the cost of the liquefied gas carrier is increased, and the fuel is additionally consumed to operate the liquefaction apparatus.

The above-mentioned "Development and comparison of CO2 BOG re-liquefaction process for LNG fueled CO2 carriers", Energy, Vol. 10, pp. 10-2013-0014169, 127, 2017 proposes a technology to re-liquefy liquefied gas evaporated gas by using the cold and cold characteristics of LNG fuel, and it has been proposed that the liquefied gas liquefying apparatus cost of the liquefied gas carrier using LNG as fuel, So that the electricity consumption can be reduced. However, according to the techniques disclosed in the above-mentioned prior arts, there is a problem that the liquefied gas evaporated gas must be transferred to the re-liquefier using a compressor, or a part of the liquefied gas in a liquid state must be transferred to the re-liquefier with a pump.

In order to re-liquefy boil-off gas (BOG), liquefied gas can be re-liquefied by transferring it out of the tank. In this case, a compressor These costs need to be reduced because additional costs are incurred while using them. Another method for re-liquefying boil-off gas (BOG) is to transfer a portion of the liquefied gas in the liquid state out of the tank, cool it to a temperature lower than the storage temperature of the liquefied gas, It is possible to liquefy the evaporated gas above the storage tank. However, in this case, the temperature of the liquefied gas to be cooled must be higher than the design temperature at which the material of the liquefied gas storage tank can withstand. In the case of LPG carriers, cargoes stored at temperatures near -50 ° C may be transported. Storage tanks can not be used at temperatures below -60 ° C. In the case of a CO2 carrier, it can be stored and transported at around -50 ° C. If it is cooled below -56.5 ° C, which is the triple point of CO2, CO2 may become solidified and cause damage to piping and equipment. In order to avoid these problems, the width of the temperature for cooling the liquefied gas is extremely limited, which makes it impossible to reduce the amount of circulating liquefied gas, which limits the capacity of the pump. In addition, when the pump used to circulate the liquefied gas is installed in the tank, it has the disadvantage that it is difficult to access for trouble or inspection as compared with a compressor installed outside the tank.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems of the prior art, and it is an object of the present invention to provide a liquefied gas carrier for a ship using LNG as fuel, The present invention provides a liquefied gas re-liquefying apparatus and a liquefied gas carrier having the same.

According to an aspect of the invention, there is provided a liquefied gas cargo tank; A blower for feeding the evaporated gas generated in the liquefied gas cargo tank at a pressure ratio of less than 2.0; An LNG fuel consuming unit consuming LNG fuel; An LNG supply pipe for supplying LNG to the LNG fuel consuming unit; A heat exchanger connected to the LNG supply pipe to re-liquefy the liquefied gas evaporated gas transferred through the blower by using the cold / heat characteristic of the LNG fuel; And a pump for transferring the liquefied gas re-liquefied in the heat exchanger to the storage tank is provided.

The blower may be a blower having a pressure ratio of the gas at the inlet port to the outlet port being less than 1.1.

Wherein the heat exchanger comprises: a tank in which the liquefied liquefied gas is stored with a free surface; A coil or a pipe through which gas or liquid LNG flows into the tank; And piping connected at the bottom of the tank to discharge the liquefied gas stored in the liquid state in the tank.

A re-liquefied gas branch pipe branched at the downstream end of the pump to return tank-like re-liquefied liquefied gas to a heat exchanger; And a first control valve installed in the refueling gas branch pipe. The control unit may further include a sensing unit for measuring the level of the liquefied gas stored in the heat exchanger and outputting the sensing signal as a sensing signal. The sensory signal output from the sensing unit may be received and the first control valve 302 may be controlled.

And a spray pipe connected to the refueling gas branch pipe and capable of spraying the liquefied gas above the heat exchanger tank.

An LNG fuel tank for storing LNG; A transfer device for transferring a part of evaporated gas or LNG generated in the LNG fuel tank from the LNG fuel tank; An LNG re-liquefying device for re-liquefying or cooling evaporated gas or LNG transferred through the transfer device; A refrigerant branch pipe for branching the refrigerant of the LNG remelting device; A second control valve connected to the refrigerant branch pipe for branching the refrigerant of the LNG remelting device; A heat exchanger in the form of a coil and a pipe connected to the refrigerant branch pipe and passing through the tank portion of the heat exchanger; And a refrigerant return pipe for returning the refrigerant having undergone the heat exchange in the heat exchanger to the LNG re-liquefier.

An LNG return pipe for returning all or a part of the gas or liquid LNG that has passed through the heat exchanger to the LNG storage tank; And a third control valve installed in the LNG return pipe.

And an LNG re-liquefying device for re-liquefying evaporative gas generated from the LNG fuel tank and storing the re-liquefied gas into an LNG fuel tank. The LNG re-liquefier can be used as the liquefied natural gas or the LNG re-liquefier since the LNG becomes the intermediate medium and the heat exchange is performed from the liquefied gas to the coolant of the LNG re-liquefier, It can be utilized for re-liquefaction.

And an injection pipe connected to the LNG return pipe and extending to the lower portion of the LNG fuel tank. LNG supplied to the LNG consuming place is supplied to the heat exchanger for the liquefaction of the liquefied gas, supplied to the LNG consuming place, and the remaining LNG is returned to the LNG storage tank through the return pipeline, You can increase your livelihood. The returned LNG can be operated by exchanging heat with cold liquid LNG through the injection piping to distribute the temperature more evenly in the LNG fuel tank and to maintain the pressure rise of the LNG storage tank stably.

A pump for supplying LNG to the LNG fuel consuming unit; An LNG fuel return pipe branched at the downstream end of the pump to return the liquid LNG to the LNG fuel tank; A spray pipe connected to the LNG fuel return pipe and capable of dispersing LNG in a liquid state at an upper portion of the LNG fuel tank; And a fourth control valve installed in the LNG fuel return pipe. LNG supplied to the LNG consuming place is supplied to the heat exchanger for the liquefaction of the liquefied gas, supplied to the LNG consuming place, and the remaining LNG is returned to the LNG storage tank through the return pipeline, You can increase your livelihood. In this case, the pressure of the LNG storage tank may be rapidly increased due to the return of the hot LNG. By spraying the LNG with the cool liquid through the LNG spray pipe, the pressure rise of the LNG storage tank can be stably maintained have.

The heat exchanger can re-liquefy the liquefied gas evaporated gas in heat exchange with the refrigerant provided by the refrigerant circulation section, not with the LNG fuel. A second heat exchanger connected to the LNG supply pipe to cool the refrigerant circulating through the refrigerant circulation unit by using the heat and cold characteristic of the LNG fuel; A refrigerant circulation line installed to circulate the refrigerant in the heat exchanger and the second heat exchanger; And a circulation pump for providing a pumping force for circulation of the refrigerant through the refrigerant circulation line.

The heat exchanger re-liquefies the liquefied gas evaporated gas in heat exchange with the refrigerant provided by the refrigerant circulation unit, not with the LNG fuel, and the refrigerant circulation unit is connected to the pipe for supplying the LNG as fuel so that the refrigerant circulation unit A third heat exchanger for cooling the refrigerant by heat exchange with the refrigerant; A fourth heat exchanger connected to the refrigerant branch pipe of the LNG remelting unit to cool the refrigerant in the separate refrigerant circulation unit using the refrigerant of the LNG re-liquefier; A refrigerant circulation line installed to circulate refrigerant to the heat exchanger, the third heat exchanger and the fourth heat exchanger; A first refrigerant branch pipe for supplying a refrigerant to the third heat exchanger; A second refrigerant branch pipe for supplying refrigerant to the fourth heat exchanger; A fifth control valve installed in the first refrigerant branch pipe to regulate the amount of the refrigerant; A sixth control valve (915) installed in the second refrigerant branch pipe for controlling the amount of refrigerant; And a circulation pump for providing a pumping force for circulation of the separate refrigerant through the refrigerant circulation line.

According to another aspect of the present invention, there is provided a liquefied gas carrier using LNG as a fuel having a liquefied gas res liquefaction device for liquefying liquefied gas using LNG.

According to the present invention, the liquefaction gas of the liquefied gas carrier can be re-liquefied using the LNG fuel to reduce the cost of the liquefaction device and the operation cost thereof.

It is possible to transfer liquefied gas that has been re-liquefied by a small-capacity pump by transferring the evaporated gas to a blower with low cost and electricity consumption and transferring only the liquefied liquid to the pump.

Also, maintenance can be simplified by using a blower, which is simple equipment compared to the compressor, and installing the pump outside the liquefied gas storage tank.

FIG. 1 is a configuration diagram showing an apparatus for liquefied gas re-liquefaction using LNG fuel according to a first embodiment of the present invention.
2 and 3 are block diagrams showing an apparatus for liquefied gas re-liquefaction using LNG fuel according to a second embodiment of the present invention.
FIG. 4 is a configuration diagram illustrating an apparatus for liquefied gas re-liquefaction using LNG fuel according to a third embodiment of the present invention.
5 and 6 are block diagrams showing an apparatus for liquefied gas re-liquefaction using LNG fuel according to a fourth embodiment of the present invention.
FIG. 7 is a block diagram illustrating an apparatus for liquefying a liquefied gas using LNG fuel according to a fifth embodiment of the present invention.
FIG. 8 is a configuration diagram showing an apparatus for liquefied gas re-liquefaction using LNG fuel according to a sixth embodiment of the present invention.
FIG. 9 is a configuration diagram showing an apparatus for liquefied gas re-liquefaction using LNG fuel according to a seventh embodiment of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention is capable of various modifications and various embodiments, and specific embodiments are illustrated in the drawings and described in detail in the detailed description. It should be understood, however, that the present invention is not intended to be limited to the specific embodiments, but includes modes, equivalents, and alternatives falling within the spirit and scope of the present invention. In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a liquefied gas liquefaction apparatus using LNG and a liquefied gas carrier having the same according to the present invention will be described in detail with reference to the accompanying drawings. In the following description, Are denoted by the same reference numerals, and redundant description thereof will be omitted.

The liquefied gas in the present invention may include all the liquefied gas having higher liquefaction point than the LNG such as LPG, CO2, Ethane, and DME. The liquefied gas carrier may store one or more kinds of liquefied gas having higher liquefaction point than the LNG Lt; RTI ID = 0.0 > a < / RTI > liquefied gas carrier.

FIG. 1 is a configuration diagram showing an apparatus for liquefied gas re-liquefaction using LNG fuel according to a first embodiment of the present invention.

1, an apparatus 100 for liquefying gas using liquefied natural gas (LNG) fuel according to an embodiment of the present invention includes a liquefied gas cargo tank 10 installed in a ship (not shown), a liquefied gas storage tank 10 A blower 20 for feeding the generated evaporation gas at a pressure ratio of less than 2.0, an LNG fuel consuming unit 42 for consuming LNG fuel, an LNG supply pipe 41 for supplying LNG to the LNG fuel consuming unit 42, A heat exchanger 30 connected to the supply pipe 41 to re-liquefy the liquefied gas evaporated gas transferred through the blower 20 by utilizing the cold and heat characteristic of the LNG fuel, and a liquefied gas liquefied in the heat exchanger 30 To the storage tank (10).

The LNG fuel consuming unit 42 transfers the LNG to the outside of the LNG fuel storage tank (Figures 4 and 420), such as the engine or the generator using the LNG as fuel, 420). ≪ / RTI >

The blower 20 may be a blower having a pressure ratio of the gas at the inlet port and the outlet port being less than 1.1.

The purpose of the blower 20 is to circulate the liquefied gas evaporated gas generated in the liquefied gas cargo tank 10 to the storage tank 10 through the first heat exchanger 30 to resupply the liquefied gas, It is necessary to raise the flow rate so that the flow rate to be re-liquefied can be circulated in consideration of the pressure reduction in the first heat exchanger 30 and the piping flows while circulating. The pressure drop in the piping is greater than when the flowing fluid is in the liquid phase. Accordingly, in this patent, a compressor having a pressure ratio of 2.0 or more, which is expensive in price, is excluded and a low-pressure blower 20 having a pressure ratio of less than 2.0 is installed to form a smooth flow of gaseous evaporative gas, It is possible to provide a smooth flow of the liquid when the pump 40 is provided at the rear end of the pump 30. The amount of pressure reduction between the rear end of the blower 20 and the first heat exchanger 30 is small and since the pump 40 is provided after the first heat exchanger 30, It is possible to smooth fluid flow and re-liquefaction process.

In addition, since the discharge pressure of the blower 20 is low, the design pressure of the heat exchanger is lowered, and the cost of the heat exchanger is reduced. And it is easy to operate and manage the blower.

The pump 40 is installed for the purpose of returning the re-liquefied liquefied gas and can be applied to a low-cost pump having a relatively small capacity, and is installed outside the liquefied gas storage tank 10, . The re-liquefied liquefied gas can be boosted and transported again by the pump 40, so that the design limit on the back pressure applied to the first heat exchanger 30 and the liquefied gas storage tank 10 is reduced. That is, when the fluid is returned only by the pressure difference between the first heat exchanger 30 and the liquefier tank storage tank 10 without the pump, if the diameter of the return pipe is small, the pressure decrease becomes large and the liquefied liquefied gas is entirely returned And the diameter of the return pipe must be designed to be sufficiently large in consideration of this. As the diameter of the return pipe increases, the material cost increases and the surface area of the pipe increases, which increases the amount of heat penetration from the outside, which causes the re-liquefied liquefied gas to vaporize and be returned to the storage tank. In this patent, the design restriction on the back pressure of the return pipe is reduced by the pressure increase by the pump 40, so that the pipe diameter can be set to be smaller, and there is no limitation on the type and the specification of the pump 40. [

There is no limitation on the type and the specification of the first heat exchanger (30).

2 is a configuration diagram showing an apparatus for liquefied gas re-liquefaction using LNG fuel according to the second embodiment.

2, an apparatus 200 for liquefied gas using liquefied natural gas (LNG) fuel according to the present embodiment includes a liquefied gas cargo tank 10 installed in a ship (not shown), a liquefied gas cargo tank 10 A blower 20 for feeding the generated evaporation gas at a pressure ratio of less than 2.0, an LNG fuel consuming unit 42 for consuming LNG fuel, an LNG supply pipe 41 for supplying LNG to the LNG fuel consuming unit 42, A first heat exchanger 30 connected to the supply pipe 41 to re-liquefy the liquefied gas evaporated gas transferred through the blower 20 by utilizing the cold and heat characteristic of the LNG fuel, And a pump (40) for transferring the liquefied liquefied gas to the storage tank (10), wherein the first heat exchanger (30) comprises a heat exchange tank (211) in which the re-liquefied liquefied gas is stored with a free water surface, A first heat exchange coil or pipe 212 through which gas or liquid LNG flows into the tank 211 for heat exchange, 211 in may be in the form containing the re-liquefied gas discharge pipe 213 is connected to the liquefied gas from the tank bottom to be discharged is stored in a liquid state.

The first heat exchanger (30) is configured in the form of a heat exchange tank (211) in which a liquefied gas has a free water surface and a gas and a liquid are separated, so that the gaseous evaporative gas flows into the pump (40) It is possible to avoid the problem that the liquefied gas is locally frozen and clogged because the liquefied gas does not pass through the narrow flow path in the heat exchanger.

Liquefied gas branch pipe 301 and the liquefied gas branch pipe 301 which are branched from the rear end of the pump 40 and return the liquefied gas to the first heat exchanger 30 as shown in Fig. The first control valve 302 may include a first control valve 302, The first control valve 302 further includes a sensing unit 304 for measuring the level of the liquefied gas stored in the first heat exchanger 30 and outputting the detected level as a sensing signal. The sensing unit 304 receives the sensing signal output from the sensing unit 304, Can be controlled. When the level of the liquefied gas is low, the amount of the liquefied gas returned to the heat exchanger is increased by opening the first control valve 302, so that the evaporated gas in the gaseous state flows into the pump 40 or the pump 40 is tripped And when the level of the liquefied gas is high, the amount of the liquefied gas to be returned by closing the first control valve 302 may be reduced to reduce the possibility of flooding the liquefied gas stored in the tank. In addition, according to the level of the liquefied gas stored in the heat exchanger tank, the operation stoppage of the pump is frequently operated, complicating the operation and reducing the life of the pump.

And a first spray unit 303 connected to the re-liquefied gas branch pipe 301 and capable of spraying the liquefied gas above the tank 211. The liquefied gas is uniformly injected into the tank through the spray, so that the heat exchange in the tank can be uniformly performed, thereby promoting the re-liquefaction phenomenon of the liquefied gas evaporated gas.

FIG. 4 is a configuration diagram showing an apparatus for liquefied gas re-liquefaction using LNG fuel according to the third embodiment.

4, an apparatus 400 for liquefying gas using liquefied natural gas (LNG) fuel according to the present embodiment includes a liquefied gas cargo tank 10 installed in a hull (not shown), a liquefied gas cargo tank 10 A blower 20 for feeding the generated evaporation gas at a pressure ratio of less than 2.0, an LNG fuel consuming unit 42 for consuming LNG fuel, an LNG supply pipe 41 for supplying LNG to the LNG fuel consuming unit 42, A first heat exchanger 30 connected to the supply pipe 41 to re-liquefy the liquefied gas evaporated gas transferred through the blower 20 by utilizing the cold and heat characteristic of the LNG fuel, And a pump (40) for transferring liquefied liquefied gas to the storage tank (10), wherein the first heat exchanger (30) comprises a heat exchange tank (211) in which the re-liquefied liquefied gas is stored with a free water surface, A first heat exchange coil or pipe 212 through which gas or liquid LNG flows into the tank 211 for heat exchange, An LNG storage tank 420 for storing an LNG used as a fuel, and an LNG storage tank 220 for storing LNG stored in the LNG storage tank 211, An LNG transferring unit 430 for transferring a part of the LNG or the evaporation gas generated in the fuel tank from the LNG fuel tank, and a first LNG re-liquefying unit 430 for re-liquefying or cooling the evaporation gas or LNG transferred through the LNG transferring unit 430. [ A first refrigerant branch pipe 411 for branching the refrigerant in the first LNG remoher unit 410 and a second refrigerant branch pipe 411 connected to the first refrigerant branch pipe 411 for branching the refrigerant in the LNG re- A second heat exchange coil or pipe 414 connected to the first refrigerant branch pipe 411 and passing through the heat exchange tank 211 of the first heat exchanger 30; And a first refrigerant return pipe 413 for returning the refrigerant having undergone heat exchange in the second heat exchange coil or pipe 414 to the first LNG material liquefier 410. [

The LNG fuel storage tank 420 generates boil-off gas (BOG) due to external heat invasion, and the pressure of the LNG fuel tank 420 increases. The first LNG re-liquefier 410 includes all of the apparatuses configured to re-liquefy the LNG vaporized gas to suppress the pressure rise of the LNG fuel storage tank 420. [ The refrigerant of the refrigerant cycle reclosing device composed of the compressor, the heat exchanger and the expansion valve shown in FIG. 4 can be produced. However, FIG. 4 is an example of the re-liquefying device and is not limited to this equipment configuration. The LNG re-liquefier 410 can be constructed. The LNG evaporating gas transferred to the first LNG remelting unit 410 can be directly re-liquefied. A portion of the LNG in the liquid state is transferred from the LNG fuel storage tank 420 to the first LNG re-liquefier 410, the cooled LNG is returned to the LNG fuel storage tank 420, May be an indirect LNG re-liquefier 410 that liquefies the vaporized gas in the LNG fuel tank or lowers the LNG temperature in the LNG fuel tank to reduce the pressure.

The refrigerant of the first LNG remelting unit 410 is partially or entirely transferred to the second heat exchanger coil or the pipe 414 through the first refrigerant branch pipe 411 to perform heat exchange with the liquefied gas evaporating gas, It is possible to increase the re-gasification of the gas. A second regulating valve 412 may be used to regulate the amount of refrigerant delivered through the first refrigerant branch line 411.

FIG. 5 is a configuration diagram showing an apparatus for liquefied gas re-liquefaction using LNG fuel according to the fourth embodiment.

5, an apparatus 500 for liquefying gas using liquefied natural gas (LNG) fuel according to the present embodiment includes a liquefied gas cargo tank 10 installed in a hull (not shown), a liquefied gas cargo tank 10 A blower 20 for feeding the generated evaporation gas at a pressure ratio of less than 2.0, an LNG fuel consuming unit 42 for consuming LNG fuel, an LNG supply pipe 41 for supplying LNG to the LNG fuel consuming unit 42, A first heat exchanger 30 connected to the supply pipe 41 to re-liquefy the liquefied gas evaporated gas transferred through the blower 20 by utilizing the cold and heat characteristic of the LNG fuel, And a pump 40 for transferring the liquefied liquefied gas to the storage tank 10 so that all or a part of the gas or liquid LNG that has passed through the first heat exchanger 30 is supplied to the LNG fuel storage tank 420 The third control valve 520 installed in the LNG return pipe 510 and the LNG return pipe 510 returning the LNG return pipe.

The LNG consumer 42 may be an engine, a generator, a gas combustion unit (GCU), or a pipe for venting outboard. When the LNG consumption amount of the LNG consuming unit 42 such as an engine or a generator is high, a sufficient amount of LNG passes through the first heat exchanger 30 to efficiently re-liquefy the liquefied gas. However, If the amount of LNG fuel consumed by the LNG consuming party 42 is not large, it is possible to reduce the reduction of the liquefied gas re-liquefaction by burning it in the GCU or discharging it to the atmosphere and using the LNG fuel.

According to one aspect of the present embodiment, when the LNG fuel consumption amount of the LNG consuming place is not low, the LNG fuel is not transferred to the first heat exchanger 30 by the amount of LNG fuel consumption, It is possible to transfer a large amount of LNG fuel to the first heat exchanger (30). In this case, the LNG exceeding the consumption amount of the LNG consumer can be returned to the LNG fuel storage tank 420 through the LNG return pipe 510 after being used for the liquefied gas re-liquefaction in the heat exchanger.

The amount of gas or liquid LNG returned to the LNG fuel tank through the LNG return pipe 510 can be adjusted through the third control valve 520.

As shown in FIG. 6, the LNG fuel storage tank 420 may further include an LNG re-liquefier. Liquefied natural gas (LNG) returned to the LNG storage tank 420 through the LNG return pipe 510 is re-liquefied by using the second LNG removers 610, so that a part of the LNG fuel circulates In this circulation process, energy is increased in the first heat exchanger (30) and energy is reduced in the second LNG remelting device (610). This phenomenon is similar to the fact that LNG becomes an intermediate medium and heat exchange is performed from the liquefied gas to the refrigerant of the LNG liquefaction device, so that the LNG liquefaction device can be utilized for liquefaction of the liquefied gas. In particular, the amount of LNG that can be treated by the LNG consumer 42 is supplied to the first heat exchanger 30 to be used for liquefied gas re-liquefaction, and the remaining LNG supplied to the LNG consumer 42 The second LNG re-liquefier 610 is operated while returning the liquefied gas to the LNG fuel storage tank 420 through the return pipe 510 to increase the liquefied gas re-liquefaction quantity, thereby reliably operating the pressure of the LNG fuel storage tank 420 have

As shown in FIG. 6, the gas or liquid LNG returned through the LNG return pipe 510 can be injected into the LNG through the LNG injection unit 620 connected to the lower part of the tank. When injected into the upper portion of the LNG storage tank 420, the pressure in the gas region rises rapidly before heat exchange with the LNG in the narrow gas region in the upper portion, which may pose a risk to the safety of the LNG fuel tank, The LNG fuel tank pressure can rise steeply because it is made from the top of the liquid LNG. Accordingly, the LNG is injected into the lower portion of the LNG fuel tank through the LNG injecting unit 620 to perform heat exchange with the LNG in the cool liquid state, and the pressure can be increased more stably.

FIG. 7 is a configuration diagram showing an apparatus for liquefied gas re-liquefaction using LNG fuel according to the fifth embodiment.

7, an apparatus 700 for liquefied gas using liquefied natural gas (LNG) fuel according to the present embodiment includes a liquefied gas cargo tank 10 installed in a ship (not shown), a liquefied gas cargo tank 10 A blower 20 for feeding the generated evaporation gas at a pressure ratio of less than 2.0, an LNG fuel consuming unit 42 for consuming LNG fuel, an LNG supply pipe 41 for supplying LNG to the LNG fuel consuming unit 42, A first heat exchanger 30 connected to the supply pipe 41 to re-liquefy the liquefied gas evaporated gas transferred through the blower 20 by utilizing the cold and heat characteristic of the LNG fuel, An LNG fuel pump 710 for supplying LNG from the LNG fuel storage tank 420 to the LNG fuel consuming place 42; and a pump 40 for transferring the liquefied liquefied gas to the storage tank 10; An LNG fuel return pipe 720 branching from the downstream end of the LNG fuel pump 710 to return the LNG in the liquid state to the LNG fuel tank; An LNG spray unit 740 connected to the LNG fuel return pipe 720 and capable of dispersing LNG in a liquid state at an upper portion of the LNG fuel tank; And a fourth control valve 730 installed in the LNG fuel return pipe 720.

LNG fuel is supplied to the first heat exchanger (30) as much as the LNG fuel consumption amount when the LNG consumption amount of the LNG consuming place is not low, and the larger amount of the LNG fuel is supplied to the first heat exchanger To the heat exchanger (30). In this case, the LNG exceeding the consumption amount of the LNG consumer can be returned to the LNG fuel tank through the LNG return pipe (510) after being used for liquefied gas re-liquefaction in the heat exchanger. The energy of the LNG fuel in the LNG fuel storage tank 420 is further increased by the returned LNG and this energy increase causes the temperature and pressure of the LNG fuel stored in the LNG fuel tank to increase. If the temperature of the stored LNG is not evenly distributed and the temperature near the free water surface is high, the pressure of the LNG evaporation gas may rise more rapidly. In Embodiment 5, while the LNG fuel is supplied to the LNG fuel pump 710, a part of the LNG fuel is returned to the LNG fuel storage tank 420 in a cold state before the first heat exchanger 30 and is injected in the LNG fuel storage tank 420 It is possible to prevent the temperature of the LNG free water surface from rising sharply, thereby reducing the possibility that the pressure of the LNG fuel storage tank 420 rapidly increases.

The amount of LNG that is larger than the amount of LNG that can be processed by the LNG consumer 42 is supplied to the first heat exchanger 30 to be used for the liquefaction gas re-liquefaction, and the LNG remaining after being supplied to the LNG consumer 42 is returned And is returned to the LNG fuel storage tank 420 through the pipe 510 to increase the liquefied gas re-liquefaction capacity. At this time, the pressure of the LNG fuel storage tank 420 may be drastically increased due to the return of the LNG having a high energy. The LNG is sprayed from the upper part through the LNG spray part 740 to increase the pressure of the LNG storage tank Can be operated stably.

8 is a configuration diagram showing an apparatus for liquefied gas re-liquefaction using LNG fuel according to the sixth embodiment.

8, the liquefied gas re-liquefaction apparatus 800 using LNG fuel according to the present embodiment includes a liquefied gas cargo tank 10 installed in a ship (not shown), a liquefied gas cargo tank 10 installed in a liquefied gas cargo tank 10 A blower 20 for feeding the generated evaporation gas at a pressure ratio of less than 2.0, an LNG fuel consuming unit 42 for consuming LNG fuel, an LNG supply pipe 41 for supplying LNG to the LNG fuel consuming unit 42, A first heat exchanger 30 connected to the supply pipe 41 to re-liquefy the liquefied gas evaporated gas transferred through the blower 20 by utilizing the cold and heat characteristic of the LNG fuel, And a pump 40 for transferring the liquefied liquefied gas to the storage tank 10, wherein the first heat exchanger 30 is connected to the refrigerant circulation unit 810, not the LNG fuel, And the refrigerant circulating unit 810 is connected to the LNG supply pipe 41 to cool the refrigerant by using the cold heat characteristic of the LNG fuel, A second heat exchanger 812 for cooling the refrigerant circulating in the circulation part, a refrigerant circulation line 813 installed to circulate the refrigerant to the first heat exchanger 30 and the second heat exchanger 812, And a first circulation pump 811 for providing a pumping force for circulation of the refrigerant through the refrigerant circulation line 813. [

The heat medium circulation unit used in the LNG fuel supply system may be used as the refrigerant circulation unit by the refrigerant circulation unit 810. LNG used as a fuel is stored in a fuel tank in a low-temperature liquefied state in order to reduce the volume during storage. In order to be used as a fuel, the LNG is vaporized and heated to meet the requirements of a fuel consumer such as an engine or a generator. Such vaporization and heating is performed by a heating medium such as glycol, seawater or fresh water in a heat exchanger, and the heating medium cooled through heat exchange is heated by a heat source such as steam and circulated by a pump or the like. Therefore, if the heat medium of the LNG fuel supply system is cooled by heat exchange with the LNG and then heat-exchanged for re-liquefaction of the liquefied gas before being heated by a heat source such as a steam, the role of the coolant circulation unit 810 for re- In addition, there is an advantage in that the heat source such as steam can be eliminated or the capacity thereof can be reduced.

FIG. 9 is a configuration diagram showing an apparatus for liquefied gas re-liquefaction using LNG fuel according to the seventh embodiment.

9, an apparatus 900 for liquefied gas using liquefied natural gas (LNG) fuel according to the present embodiment includes a liquefied gas cargo tank 10 installed in a hull (not shown), a liquefied gas cargo tank 10 A blower 20 for feeding the generated evaporation gas at a pressure ratio of less than 2.0, an LNG fuel consuming unit 42 for consuming LNG fuel, an LNG supply pipe 41 for supplying LNG to the LNG fuel consuming unit 42, A first heat exchanger 30 connected to the supply pipe 41 to re-liquefy the liquefied gas evaporated gas transferred through the blower 20 by utilizing the cold and heat characteristic of the LNG fuel, And a pump 40 for transferring the liquefied liquefied gas to the storage tank 10, wherein the first heat exchanger 30 is connected to the refrigerant circulation unit 910, not the LNG fuel, And the refrigerant circulating unit 910 is connected to a pipe for supplying the LNG as fuel, and uses the low temperature characteristic of the LNG Third heat exchanger 916 to cool the refrigerant by heat exchange between the refrigerant and to provide additional refrigerant cycle and; A fourth heat exchanger (917) connected to the refrigerant branch pipe of the LNG remelting unit to cool the refrigerant in the separate refrigerant circulation unit using the refrigerant of the LNG re-liquefier; A refrigerant circulation line 918 installed to circulate refrigerant to the first heat exchanger 30, the third heat exchanger 916, and the fourth heat exchanger 917; A second refrigerant branch pipe 912 for supplying refrigerant to the third heat exchanger; A third refrigerant branch pipe 914 for supplying refrigerant to the fourth heat exchanger; A fifth control valve (913) installed in the first refrigerant branch pipe for controlling the amount of refrigerant; A sixth control valve 915 installed in the second refrigerant branch pipe to regulate the amount of refrigerant; And a second circulation pump 911 for providing a pumping force for the circulation of the separate refrigerant through the refrigerant circulation line.

The heat medium circulation unit used in the LNG fuel supply system may be used as the refrigerant circulation unit by the refrigerant circulation unit 910. LNG used as a fuel is stored in a fuel tank in a low-temperature liquefied state in order to reduce the volume during storage. In order to be used as a fuel, the LNG is vaporized and heated to meet the requirements of a fuel consumer such as an engine or a generator. Such vaporization and heating is performed by a heating medium such as glycol, seawater or fresh water in a heat exchanger, and the heating medium cooled through heat exchange is heated by a heat source such as steam and circulated by a pump or the like. Therefore, if the heat medium of the LNG fuel supply system is cooled by heat exchange with the LNG and then heat-exchanged for liquefied gas re-liquefaction before being heated by a heat source such as a steam, the role of the coolant circulation unit 910 for re- In addition, there is an advantage in that the heat source such as steam can be eliminated or the capacity thereof can be reduced.

The ship using the LNG as fuel according to the present invention may be applied to the liquefied gas remelting apparatuses 100, 200, 400, 500, 700, 800, 900 according to the first to seventh embodiments of the present invention, Lt; / RTI >

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the invention will be.

100: liquefied gas remelting apparatus (first embodiment) 10: liquefied gas cargo tank
20: blower 30: first heat exchanger
40: Pump 41: LNG fuel supply piping
42: LNG fuel consuming place 200: Liquefied gas remelting apparatus (second embodiment)
211: Heat exchange tank 212: First coil for heat exchange (or piping)
213: Re-liquefied gas discharge pipe 301: Re-liquefied gas branched pipe
302: first control valve 303: first sprayer
304: Level sensing part 400: Liquefied gas re-liquefying device (Third embodiment)
410: first LNG remelting device 411: first refrigerant branch piping
412: second control valve 413: first refrigerant return pipe
414: second coil for heat exchange (or piping) 420: LNG fuel storage tank
430: LNG transfer part 500: Liquefied gas remelting device (fourth embodiment)
510: LNG return pipe 520: Third control valve
610: Second LNG remelting device 620: LNG injection part
700: liquefied gas remelting device (fifth embodiment) 710: LNG fuel pump
720: LNG fuel return pipe 730: Fourth regulating valve
740: LNG spray unit 800: Liquefied gas remelting apparatus (sixth embodiment)
810: Refrigerant circulation part 811: First circulation pump
812: Second heat exchanger 813: Refrigerant circulation line
900: Liquefied gas remelting device (seventh embodiment) 910: Refrigerant circulation part
911: second circulation pump 912: second refrigerant branch piping
913: fifth control valve 914: third refrigerant branch piping
915: sixth control valve 916: third heat exchanger
917: fourth heat exchanger 918: refrigerant circulation line

Claims (15)

A liquefied gas cargo tank (10);
A blower 20 for feeding the evaporated gas generated in the liquefied gas cargo tank 10 at a pressure ratio of less than 2.0;
An LNG fuel consuming unit 42 consuming LNG fuel;
An LNG fuel supply line 41 for supplying LNG to the LNG fuel consuming unit 42;
A first heat exchanger (not shown) disposed upstream of the LNG fuel consuming unit 42 and connected to the LNG fuel supply pipe 41 to re-liquefy the liquefied gas evaporated gas conveyed through the blower 20 by using the L / (30); And
And a pump (40) for transferring the liquefied gas re-liquefied by heat exchange in the first heat exchanger (30) to the liquefied gas cargo tank (10). The method according to claim 1,
Wherein the blower (20) is a blower having a pressure ratio of the gas at the inlet port and the gas outlet port is less than 1.1. The method according to claim 1,
The first heat exchanger (30)
A heat exchange tank 211 in which the re-liquefied liquefied gas is stored with a free water surface;
A first coil or pipe through which a gaseous NG or liquid LNG flows into the heat exchange tank 211; And
And a re-liquefied gas discharge pipe (213) connected to the bottom of the heat exchange tank (211) to discharge a liquefied gas stored in a liquid state in the heat exchange tank (211) Gas remelting device. The method of claim 3,
A re-liquefied gas branch pipe (301) for returning the re-liquefied liquefied gas branched from the rear end of the pump (40) to the heat exchange tank (211); And
And a first regulating valve (302) installed in the re-liquefied gas branch pipe (301). 5. The method of claim 4,
Further comprising a level sensing unit (304) for measuring the level of the liquefied gas stored in the heat exchange tank (211) and outputting a sensing signal,
And the first control valve (302) is controlled by receiving the sensing signal output from the level sensing unit (304). The method of claim 4,
And a first spray unit (303) connected to the re-liquefied gas branch pipe (301) and capable of injecting liquefied gas onto an upper portion of the heat exchange tank (211) Device. The method of claim 3,
An LNG fuel storage tank 420 for storing LNG used as fuel;
An LNG transferring part 430 for transferring a part of evaporated gas or LNG generated in the LNG storage tank 40 from the LNG storage tank 40;
A first LNG re-liquefier 410 for re-liquefying or cooling evaporated gas or LNG delivered through the LNG feeder 430;
A first refrigerant branch piping 411 for branching the refrigerant of the first LNG removers 410;
A second regulating valve 412 connected to the first refrigerant branch pipe 411 for branching the refrigerant of the first LNG removers 410;
A second coil or pipe 414 connected to the first refrigerant branch pipe 411 for heat exchange through the heat exchange tank 211; And
And a first refrigerant return pipe (413) for returning refrigerant heat-exchanged in the heat exchange tank (211) to the first LNG material liquefier (410). The liquefied gas re- . The method according to claim 1,
An LNG fuel storage tank (420) for storing LNG fuel to be delivered to the LNG fuel consuming destination through the LNG fuel supply pipe (41);
An LNG return pipe (510) for returning all or a part of the gaseous NG or liquid LNG that has passed through the first heat exchanger (30) to the LNG fuel storage tank (420); And
And a third control valve (520) installed in the LNG return pipe (510). The method of claim 8,
And a second LNG material liquefaction device (610) for reducing the pressure rise of the LNG fuel storage tank (420) by re-liquefying the evaporated gas of the LNG fuel storage tank (420) Remelting device. The method of claim 8,
The LNG storage tank 420 is connected to the LNG return pipe 510 and extends to the lower portion of the LNG storage tank 420 so that all or a part of the LNG in the gaseous state or in the liquid state can be returned to the lower portion of the LNG storage tank 420 And an LNG injection unit (620). The method of claim 8,
An LNG fuel pump 710 for supplying LNG from the LNG fuel storage tank 420 to the LNG fuel consuming unit 42;
An LNG fuel return pipe 720 branched from the downstream end of the LNG fuel pump 710 to return the LNG in a liquid state to the LNG fuel storage tank 420;
An LNG spray unit 740 connected to the LNG fuel return pipe 720 and capable of dispersing LNG in a liquid state in an upper portion of the LNG fuel storage tank; And
And a fourth control valve (730) provided in the LNG fuel return pipe (720). A liquefied gas cargo tank (10);
A blower 20 for feeding the evaporated gas generated in the liquefied gas cargo tank 10 at a pressure ratio of less than 2.0;
An LNG fuel consuming unit 42 consuming LNG fuel;
An LNG fuel supply line 41 for supplying LNG to the LNG fuel consuming unit 42;
A first heat exchanger (30) for re-liquefying the liquefied gas evaporated gas transferred through the blower (20) through heat exchange with a refrigerant provided by the refrigerant circulation unit (810);
A second heat exchanger (812) connected to the LNG fuel supply pipe (41) to cool the refrigerant circulating through the refrigerant circulation unit (810) by using the cold / heat characteristic of the LNG fuel;
A refrigerant circulation line 813 for circulating and supplying the refrigerant to the first heat exchanger 30 and the second heat exchanger 812; And
And a first circulation pump (811) for providing a pumping force for circulating the refrigerant through the refrigerant circulation line (813). A liquefied gas cargo tank (10);
A blower 20 for feeding the evaporated gas generated in the liquefied gas cargo tank 10 at a pressure ratio of less than 2.0;
An LNG fuel storage tank 420 for storing LNG used as fuel;
An LNG fuel consuming unit 42 consuming LNG fuel;
An LNG fuel supply pipe (41) for supplying LNG from the LNG fuel storage tank (420) to the LNG fuel consuming place (42);
A third heat exchanger 916 connected to the LNG fuel supply pipe 41 to cool the refrigerant by heat exchange with another refrigerant provided by the separate refrigerant circulation unit 910 using the low temperature characteristic of the LNG;
A first heat exchanger (30) for re-liquefying liquefied gas evaporated gas transferred through the blower (20) through heat exchange with a refrigerant provided by the refrigerant circulation unit (910);
An LNG transferring part 430 for transferring the evaporated gas or LNG part evaporated in the LNG storage tank 420 from the LNG storage tank;
A first LNG re-liquefier 410 for re-liquefying or cooling evaporated gas or LNG delivered through the LNG feeder 430;
A first refrigerant branch piping 411 for branching the refrigerant of the first LNG removers 410;
A fourth heat exchanger 917 connected to the first refrigerant branch pipe 411 to cool the separate refrigerant of the separate refrigerant circulation unit 910 using the refrigerant of the first LNG material liquefier 410 );
A refrigerant circulation line 918 installed to circulate separate refrigerant to the first heat exchanger 30, the third heat exchanger 916, and the fourth heat exchanger 917;
A second refrigerant branch pipe 912 for supplying the separate refrigerant to the third heat exchanger 916;
A third refrigerant branch pipe 914 for supplying the separate refrigerant to the fourth heat exchanger 917;
A fifth control valve 913 installed in the second refrigerant branch pipe 912 to regulate the amount of refrigerant;
A sixth control valve 915 installed in the third refrigerant branch pipe 914 for controlling the amount of refrigerant; And
And a second circulation pump (911) for providing a pumping force for circulating the separate refrigerant through the refrigerant circulation line (918). The method according to claim 12 or 13,
And the LNG fuel using the heat medium circulation unit of the LNG fuel supply system as the refrigerant circulation units (810, 910). A liquefied gas carrier having an apparatus for liquefying gas using LNG fuel according to any one of claims 1 to 13.

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