KR101458619B1 - Heat Circulation System of Ship Loaded Fuel Cell - Google Patents

Abstract

A thermal cycling system of a ship equipped with a fuel cell is disclosed. The thermal cycling system of a ship equipped with a fuel cell of the present invention is a power operating system for a liquefied natural gas carrier. The system is supplied with liquefied natural gas in an LNG storage tank provided in the hull and stores the natural gas in a medium pressure state. Pressure buffer unit for supplying the stored liquefied natural gas to the fuel cell by vaporizing the stored liquefied natural gas when the supply of the fuel is stopped; A fuel cell unit that receives fuel from the LNG storage tank or the intermediate-pressure buffer unit; And a heat circulation unit for supplying heat necessary for vaporizing the liquefied natural gas to the intermediate-pressure buffer unit, using the high-temperature exhaust generated in the fuel cell unit as a heat source.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a heat-

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a thermal circulation system for a ship equipped with a fuel cell, and more particularly, to a system for storing a liquefied natural gas in an intermediate pressure state in preparation for shutting off fuel supply from a LNG storage tank to a fuel cell, To a thermal cycling system of a ship equipped with a fuel cell capable of vaporizing a liquefied natural gas at a medium pressure with water heated by exhaust and supplying the gas to the fuel cell.

Fuel cells are power generation devices that convert chemical energy of reactants (hydrogen and oxygen) directly into electrical energy by electrochemical reaction, and are excellent in environmental harmony and high power generation efficiency is expected.

Such fuel cells are classified into a low-temperature type and a high-temperature type, and representative examples of the high-temperature type include a molten carbonate fuel cell (MCFC) and a solid oxide fuel cell.

The characteristics of the high temperature type fuel cell can be summarized as follows. MCFC can use various kinds of fuels such as natural gas and coal gas. It can produce electricity by electrochemical reaction that converts fuel directly into electricity at about 650 ° C without combustion process. .

In the case of a solid oxide fuel cell, it operates at a high temperature of 1000 ° C or higher and uses a variety of fuels such as natural gas, coal gas, and methanol. Therefore, combined power generation using high temperature and high pressure steam generated at the rear end of the fuel cell is possible.

In addition, since there is no combustion process and electricity is generated directly from fuel, it is attracting attention as next generation power generation because there is little noise and air pollutant emission.

The unit cell of such an MCFC includes an anode and a cathode at which an electrochemical reaction takes place, a separator for forming a flow path for a fuel gas and an oxidant gas, a collecting plate for collecting charges, An electrolyte plate made in the form of a sheet and a matrix for accommodating the molten carbonate for the sake of convenience. When the fuel gas is supplied to the anode and the oxidant gas is supplied to the cathode, an electrochemical reaction occurs at each electrode, Power is obtained.

1 is a view schematically showing an example of a fuel cell system of a conventional fuel cell-equipped ship to which such a fuel cell is applied to an LNG carrier.

First, a state in which the evaporative gas is normally supplied to the fuel cell 13 will be described. The evaporated gas generated in the storage tank is supplied to the humidifier 11 through the connection passage L. [ At the same time, the evaporation gas is compressed through the compressor 21 and then stored in the evaporation gas storage tank 23 via the cooler 22. The evaporation gas stored in the evaporation gas storage tank 23 is supplied to the humidifier 11 .

The evaporated gas supplied to the humidifier 11 is mixed with the liquid vaporized in the humidifier 11 to become a wet evaporated gas. The moisture evaporated gas is supplied to the reformer 12, reformed into hydrogen and carbon dioxide in the reformer 12, and the reformed hydrogen and carbon dioxide are supplied to the fuel cell 13.

The anode of the fuel cell 13 receives hydrogen and carbon dioxide and acts on the oxidizing gas containing oxygen supplied to the cathode through the blower 14 and the air heater 15 to generate electricity by an electrochemical reaction.

On the other hand, when the supply of the evaporative gas through the connection passage L is interrupted, the sensor 24 recognizes it and sends a signal to the control unit. Typically, when loading and unloading of LNG is carried out, all equipment and piping connected to LNG storage tank except piping and equipment for LNG loading and unloading are locked according to Cargo Operation Manual, and LNG and BOG The line is locked, and the evaporation gas supply is stopped. At this time, the control unit opens the valve provided in the buffer connection channel based on the above-mentioned signal, and the evaporation gas stored in the evaporation gas storage tank 23 is regulated in temperature and pressure through the regulator 25 and the heater 26 And is supplied to the humidifier 11. The evaporated gas supplied to the humidifier 11 is used as fuel for the fuel cell 13 after passing through the humidifier 11 and the reformer 12 as described above.

The conventional buffer fuel system of the fuel cell system compresses and stores the evaporation gas (BOG) generated during the operation of the LNG carrier and supplies the stored evaporative gas to the fuel cell when the supply of fuel from the storage tank is stopped. However, by storing the evaporation gas at a high pressure of 200 bar or more, shipboard placement was very limited according to the ship's high pressure regulations. In addition, since there are many additional equipments for storing high-pressure evaporative gas such as high-pressure compressor, high-pressure tank, and safety equipment, installation cost is high and the risk of high-pressure gas storage is also problematic. On the other hand, when the liquefied natural gas is stored in a state of being stored in a liquefied natural gas, it needs to be supplied to the fuel cell by vaporizing it. Therefore, a separate vaporizing device such as a boiler is required, which complicates the system configuration and increases the cost burden.

It is an object of the present invention to provide a buffer gas unit for a marine fuel cell which can be continuously operated without stopping the operation of the fuel cell even when the supply of fuel to the fuel cell is interrupted, To solve the conventional problems that require a large amount of equipment cost. Also, we propose an economical and efficient fuel cell system by utilizing the heat energy generated from the existing system without adding a separate heat source.

According to an aspect of the present invention, in a power operation system of a liquefied natural gas carrier,

The LNG storage tank is supplied with the liquefied natural gas to store the liquefied natural gas in a medium pressure state and supplies the liquefied natural gas to the fuel cell when the liquefied natural gas is supplied from the LNG storage tank to the fuel cell, unit;

A fuel cell unit receiving fuel from the LNG storage tank or the intermediate pressure buffer unit; And

And a heat circulation unit for supplying heat required for vaporization of the liquefied natural gas to the medium pressure buffer unit using high temperature exhaust generated from the fuel cell unit as a heat source.

A heat exchanger for exchanging the high-temperature exhaust gas generated from the fuel cell unit with fresh water and supplying the heated fresh water to the intermediate-pressure buffer unit; and a control unit for controlling the direct- And an inverter for converting the input signal.

Pressure buffer unit to vaporize the liquefied natural gas and cool the cooled fresh water to circulate through the inverter and cool the inverter before being supplied to the heat exchanger.

The intermediate pressure buffer unit comprises a pump provided in the hull and pumping the liquefied natural gas supplied from the LNG storage tank to transfer the liquefied natural gas to a medium pressure state, an intermediate pressure tank in which the medium pressure liquefied natural gas transferred from the pump is stored, A vaporizer for vaporizing the medium-pressure liquefied natural gas stored in the intermediate-pressure tank, and a valve provided in the buffer connection channel for connecting the vaporizer and the fuel cell unit and for opening and closing the buffer connection channel.

The intermediate pressure buffer unit further includes a medium pressure heat exchanger for liquefying the buffer evaporation gas generated in the intermediate pressure tank by heat exchange with the liquefied natural gas supplied from the LNG storage tank, wherein the liquefied natural gas, which has passed through the medium pressure heat exchanger, Gas is introduced into the fuel cell unit when it is vaporized by heat exchange with the gas, and can be recovered to the LNG storage tank if it is in a liquid state.

Pressure buffer unit includes a sensor provided in a connection passage connecting the LNG storage tank and the fuel cell unit to detect whether evaporative gas generated in the LNG storage tank is supplied to the connection passage, And a control unit for opening / closing the valve.

The fuel cell unit includes a humidifier for humidifying the evaporation gas supplied from the LNG storage tank or the intermediate pressure buffer unit, a reformer for reforming the evaporation gas into hydrogen and carbon dioxide, And an air heater for heating the air supplied to the fuel cell through the blower. The air conditioner according to claim 1, can do.

According to another aspect of the present invention, in a fuel supply method for a marine fuel cell using a boil-off gas supplied from an LNG storage tank of a hull,

1) storing a part of the liquefied natural gas stored in the LNG storage tank in a medium pressure liquid state; And

2) supplying the fuel gas to the fuel cell by vaporizing the medium-pressure liquefied natural gas at the time of stopping the supply of the evaporation gas to the fuel cell,

There is provided a fuel supply method for a vessel equipped with a fuel cell, characterized by vaporizing the medium-pressure liquefied natural gas with water heated by exhaust gas generated from a humidifier which mixes natural gas and water vapor and supplies the natural gas to the fuel cell.

The liquefied natural gas is vaporized and the cooled water can be supplied as refrigerant to an inverter that converts the direct current power produced by the fuel cell to alternating current power.

The thermal cycling system of a ship equipped with a fuel cell of the present invention can store the liquefied natural gas at a medium pressure and can supply the liquefied natural gas in a medium pressure state Because it does not follow the ship's high-pressure regulations, it is relatively free to lay on board and the cost of additional equipment installation can be reduced. In addition, since the exhaust gas generated from the humidifier of the fuel cell system is used as a heat source, there is no need for a separate energy supply source for vaporizing the liquefied natural gas at a medium pressure, which simplifies the economical and system configuration. In addition, it is possible to realize an economical and efficient fuel cell system by vaporizing the liquefied natural gas at a medium pressure and using the cooled water as a refrigerant in the inverter of the fuel cell system to supply a cold source and a heat source by its own thermal circulation.

1 is a view schematically showing an example of a fuel cell system of a conventional fuel cell-equipped ship.
2 is a schematic view illustrating a heat circulation system of a ship equipped with a fuel cell according to an embodiment of the present invention.

In order to fully understand the present invention, operational advantages of the present invention, and objects achieved by the practice of the present invention, reference should be made to the accompanying drawings and the accompanying drawings which illustrate preferred embodiments of the present invention.

Hereinafter, the present invention will be described in detail with reference to the preferred embodiments of the present invention with reference to the accompanying drawings. Like reference symbols in the drawings denote like elements.

2 schematically shows a heat circulation system of a ship equipped with a fuel cell according to an embodiment of the present invention.

As shown in FIG. 2, the thermal circulation system for a ship equipped with a fuel cell according to an embodiment of the present invention is a system for power operation of a liquefied natural gas carrier. The system includes a LNG storage tank provided in the hull S, Pressure buffer unit 100 for storing the LNG storage tank in the intermediate pressure state, vaporizing the stored liquefied natural gas when the supply of fuel to the fuel cell 230 from the LNG storage tank is stopped, and supplying the vaporized natural gas to the fuel cell 230, Pressure buffer unit 100 and a fuel cell unit 200 in which the high-temperature exhaust gas generated in the fuel cell unit 200 is used as a heat source and the intermediate pressure buffer unit 100 is required to vaporize liquefied natural gas And a heat circulation unit 300 for supplying heat.

The liquefaction temperature of the natural gas transported by the liquefied natural gas carrier is very low at about -163 ° C at normal pressure, so it evaporates easily when the temperature rises. Liquefied natural gas carriers have a cargo hold insulation structure to maintain liquefied natural gas liquefaction, but liquefied natural gas is constantly spontaneously vaporized in LNG storage tanks, resulting in a significant amount of boil-off gas (BOG) do. In this case, evaporation gas is generated in the liquefied natural gas storage tank at about 0.05 vol% / day. In the conventional liquefied natural gas carrier, 4 to 6 tons / hour (t) Has been evaporated and gasified. The vessel equipped with a fuel cell can supply electricity to the ship by reforming the evaporated gas and supplying it to the fuel cell as a fuel, while reducing the burden on the installation cost of the expensive evaporating gas remelting device.

In this embodiment, a part of the liquefied natural gas stored in the LNG storage tank is stored under a medium pressure of about 5 to 10 bar, preferably about 5 bar, and the liquefied natural gas stored at the time of stopping the supply of the fuel to the fuel cell 230 Vaporized and supplied to the fuel cell 230. The liquefied natural gas must be vaporized before it is supplied to the fuel cell unit, and the heat required for vaporizing the liquefied natural gas is supplied from the hot exhaust generated in the fuel cell unit 200.

The heat circulation unit 300 includes a heat exchanger 310 for exchanging hot exhaust generated from the fuel cell unit 200 with fresh water and supplying heated fresh water to the intermediate pressure buffer unit 100, And an inverter 320 for converting the DC power produced by the DC power supply 320 to an alternating current.

The buffered natural gas is vaporized in the intermediate pressure buffer unit 100 and the cooled fresh water circulates through the inverter 320 and cools the inverter 320 before being supplied to the heat exchanger 310.

That is, in the fuel cell unit 200, the natural gas in the gaseous state is mixed with the vaporized water to become the moisture evaporated gas, and proceeds to the reforming step. In the process of vaporizing the water and mixing it with the natural gas, high- The temperature of the exhaust gas discharged from the humidifier 210 of the fuel cell unit 200 is about 413.6 ° C, which is a sufficient heat source.

In this embodiment, a part of fresh water introduced into the fuel cell unit 200 is heat-exchanged with hot exhaust, and then supplied to the intermediate-pressure buffer unit 100 for heat exchange. In the intermediate-pressure buffer unit 100, the natural gas in a liquid state is vaporized by heat exchange with the heated fresh water and then supplied to the fuel cell unit 200. Fresh water is cooled in the process of vaporizing a medium pressure liquefied natural gas at -100 ° C or lower. The boiling point of liquefied natural gas is -163 ° C at 1 bar and -123 ° C at 10 bar, so it can be seen that the liquid natural gas has a low temperature of -123 ° C or lower at a medium pressure of 5 to 10 bar. Fresh water is sufficiently cooled during the heat exchange process with these liquefied natural gas.

The cooled fresh water is introduced as refrigerant into the inverter 320 that converts the direct current power produced by the fuel cell unit 200 of the present embodiment into an alternating current.

DC generated by the fuel cell unit 200 is converted into AC by switching or boosting the AC by a coil, a transformer, a capacitor or the like and then rectifying the DC into DC, Can be converted to AC and supplied to various AC power source loads. Since the inverter 320 generates heat in this process, the coolant for cooling can be supplied. In this embodiment, the coolant cooled by the heat exchange with the liquefied natural gas is used as the refrigerant of the inverter 320.

The intermediate pressure buffer unit 100 includes a pump 110 installed in the hull and pumping the liquefied natural gas supplied from the LNG storage tank to transfer the liquefied natural gas to the intermediate pressure state, A vaporizer 130 for vaporizing the liquefied natural gas at medium pressure stored in the intermediate pressure tank 120 and a buffer connection passage L1 for connecting the vaporizer 130 and the fuel cell unit 200 to each other, And a valve 140 for opening and closing the buffer connection channel L1.

The liquefied natural gas stored in the intermediate pressure tank 120 is stored in a medium pressure liquid state of 5 to 10 bar, preferably 5 bar, so that it occupies less volume than the gaseous evaporative gas stored in the tank in the conventional system. As a result of calculating the required size of the tank for supplying the buffer gas, it was confirmed that the tank size is reduced to about 1/3 when the liquid is stored under the medium pressure state, compared with the case where the high pressure gas is stored at 200 bar. This reduction in tank size is of great significance in terms of efficient utilization of the limited vessel space. In addition, since the liquefied natural gas is stored in the medium pressure state, the occurrence of BOG in the intermediate pressure tank 120 is also reduced compared to when the normal pressure is applied.

The intermediate pressure buffer unit 100 further includes a medium pressure heat exchanger 150 for liquefying the buffer evaporation gas generated in the intermediate pressure tank 120 by heat exchange with the liquefied natural gas supplied from the LNG storage tank, Is introduced into the fuel cell unit 200 when it is vaporized by heat exchange with the buffer evaporation gas, and can be recovered to the LNG storage tank in the liquid state.

Since the liquefied natural gas is stored in the intermediate-pressure tank 120, evaporative gas due to natural vaporization is generated as in the LNG storage tank. The evaporated gas generated in the intermediate-pressure tank 120 is introduced into the intermediate-pressure heat exchanger 150, is phase-changed into liquid through heat exchange with the cryogenic liquefied natural gas supplied from the storage tank, and stored again in the intermediate-pressure tank 120. The liquefied natural gas at a very low temperature can be vaporized by heat exchange with the evaporation gas. In this case, the liquefied natural gas is combined with the connection flow path L2 in the LNG storage tank through the flow path as shown in FIG. 2, Fuel. If the liquefied natural gas is not vaporized and maintains the liquid state even after the heat exchange, it is stored in the LNG storage tank through the flow path.

The intermediate pressure buffer unit 100 is provided with a sensor which is provided in a connection passage L2 connecting the LNG storage tank and the fuel cell unit 200 and detects whether evaporative gas generated in the LNG storage tank is supplied to the connection passage L2 And a control unit for opening and closing the valve 140 by a signal sensed by the sensor.

The sensor senses whether or not fuel is supplied to the fuel cell unit 200 while measuring the flow rate of the evaporated gas in the connection passage L2, and opens the valve 140 through a control unit (not shown) The liquefied natural gas stored from the natural gas storage unit 120 is supplied to the fuel cell unit 200 via the vaporizer 130.

The valve 140 of the intermediate pressure buffer unit 100 is closed when the evaporative gas is normally supplied to the fuel cell through the connection passage L2 so that the evaporative gas stored in the intermediate pressure tank 120 is supplied to the fuel cell 230 Not supplied.

The fuel cell unit 200 includes a humidifier 210 for humidifying the evaporation gas supplied from the LNG storage tank or the intermediate-pressure buffer unit 100, a reformer 220 for reforming the evaporation gas into hydrogen and carbon dioxide, A fuel cell 230 for generating electricity by electrochemical reaction between hydrogen and carbon dioxide and oxygen supplied from the cathode, a blower 240 for supplying external air to the fuel cell 230, and a blower 240 And an air heater 250 for heating the air supplied to the fuel cell.

The fuel cell unit 200 may be a generally known fuel cell configuration.

The humidifier 210 serves to humidify and supply a gas (hydrogen or oxygen) supplied as fuel to the fuel cell 230 so that the fuel cell 230 exhibits optimal performance.

The gas is used as fuel for the fuel cell 230 after passing through the humidifier 210 and the reformer 220.

The reformer 220 serves to reform the evaporation gas into hydrogen and carbon dioxide. Specifically, the supplied evaporated gas is mixed with the supplied water (fresh water) in the humidifier 210 and is phase-converted into moist fuel. The wet fuels are then reformed and high hydrocarbons, excluding methane, are removed. The methane gas reformed fuel gas is reformed into carbon dioxide and hydrogen by the supplied heat.

The fuel cell 230 of the fuel cell unit 200 is supplied with the reformed hydrogen and carbon dioxide from the cathode side through the air blower 240 and the air heater 250, And to generate electricity by causing an electrochemical reaction with the oxidizing gas.

That is, the anode side of the fuel cell is supplied with the fuel gas containing at least hydrogen, and the cathode side of the fuel cell 230 is supplied with the oxidizing gas containing at least oxygen. Electricity is obtained by a redox reaction of a fuel gas containing hydrogen and an oxidizing gas containing oxygen.

Hereinafter, the operating state of the thermal cycling system of the ship equipped with a fuel cell according to the present embodiment will be briefly described with reference to FIG.

First, a state in which the evaporative gas is normally supplied to the fuel cell 230 will be described. The evaporated gas generated in the LNG storage tank is supplied to the humidifier 210 through the connection flow path L2. At the same time, a portion of the liquefied natural gas is stored in the intermediate-pressure tank 120 at a medium pressure of about 5 bar through the pump 110, and the liquefied natural gas stored in the intermediate- (Not shown). The evaporated gas generated from the liquefied natural gas stored in the intermediate pressure tank 120 is liquefied and stored again in the intermediate pressure heat exchanger 150. The liquefied natural gas supplied from the LNG storage tank and used for heat exchange is supplied to the fuel cell unit 200 .

On the other hand, the evaporated gas supplied to the humidifier 210 is mixed with the liquid vaporized in the humidifier 210 to become a wet evaporated gas. The moisture evaporated gas is supplied to the reformer 220, reformed into hydrogen and carbon dioxide, and then supplied to the fuel cell 230.

The anode of the fuel cell 230 receives hydrogen and carbon dioxide and operates with an oxidizing gas containing oxygen supplied to the cathode through the blower 240 and the air heater 250 to generate electricity by an electrochemical reaction.

On the other hand, when the supply of the evaporative gas through the connection flow path L2 is interrupted, the sensor recognizes it and sends a signal to the control unit (not shown). The control unit opens the valve 140 to the buffer connecting flow path L1 based on the above signals so that the liquefied natural gas stored in the intermediate pressure tank 120 is supplied to the humidifier 210 via the vaporizer 130. [ Here, the temperature of the exhaust gas discharged from the humidifier 210 is about 413.6 ° C, which is a sufficient heat source. The exhaust gas is introduced into the heat exchanger 310 to heat water (fresh water) ) To vaporize the liquefied natural gas at a medium pressure. The evaporated gas supplied to the humidifier 210 is used as fuel for the fuel cell 230 after passing through the humidifier 210 and the reformer 220 as described above. The cooled water (fresh water) is supplied to the refrigerant of the inverter 320 to cool the inverter 320 and return to the heat exchanger 310 again.

According to another aspect of the present invention, in a fuel supply method for a marine fuel cell using a boil-off gas supplied from an LNG storage tank of a hull (S)

1) storing part of the liquefied natural gas stored in the LNG storage tank in a medium pressure liquid state; And

2) vaporizing the liquefied natural gas at a medium pressure when the supply of the evaporation gas to the fuel cell is interrupted, and supplying it to the fuel cell,

There is provided a fuel supply method for a vessel equipped with a fuel cell, characterized in that a liquefied natural gas at a medium pressure is vaporized by water heated by an exhaust generated in a humidifier (210) which mixes natural gas and water vapor and supplies the natural gas and water vapor to the fuel cell.

The cooled water vaporizes the liquefied natural gas at a medium pressure and can be supplied as refrigerant to the inverter 320 that converts the direct current power produced in the fuel cell to the alternating current power.

The thermal cycling system of a ship equipped with a fuel cell according to the present invention can store the liquefied natural gas at a medium pressure and supply it to the fuel cell to continuously operate the fuel cell without stopping operation to improve the availability, Because the gas is stored, it does not comply with the high pressure regulations of the ship, so it is relatively free to be placed on board and the cost of additional equipment installation can be reduced.

By using the exhaust generated from the humidifier of the fuel cell system as a heat source and vaporizing the liquefied natural gas at a medium pressure, there is no need for a separate heat energy supplying means such as a boiler, and the economic and system configuration becomes simple. In addition, it is possible to realize an economical and efficient fuel cell system by vaporizing the liquefied natural gas at a medium pressure and using the cooled water as a refrigerant in the inverter of the fuel cell system to supply a cold source and a heat source by its own thermal circulation.

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 or scope of the invention. Accordingly, such modifications or variations are intended to fall within the scope of the appended claims.

S: Hull
L1: buffer connection channel
L2: connection channel
100: Medium pressure buffer unit
110: pump
120: Medium pressure tank
130: vaporizer
140: Valve
150: Medium pressure heat exchanger
200: fuel cell unit
210: Humidifier
220: reformer
230: Fuel cell
240: blower
250: Air heater
300: thermocycling unit
310: Heat exchanger
320: Inverter

Claims (9)

A power management system for a liquefied natural gas carrier,
The LNG storage tank is supplied with the liquefied natural gas and stored in a medium pressure state. When the supply of fuel from the LNG storage tank to the fuel cell is stopped, the liquefied natural gas is vaporized and supplied to the fuel cell, A unit 100;
A fuel cell unit (200) receiving fuel from the LNG storage tank or the intermediate pressure buffer unit; And
And a heat circulation unit (300) for supplying heat necessary for vaporization of the liquefied natural gas to the intermediate-pressure buffer unit using high-temperature exhaust generated in the fuel cell unit as a heat source,
The intermediate pressure buffer unit
An intermediate pressure tank 120 in which the liquefied natural gas is stored; And
And an intermediate pressure heat exchanger (150) for liquefying the buffer evaporation gas generated in the intermediate pressure tank by heat exchange with the liquefied natural gas supplied from the LNG storage tank. 2. The apparatus of claim 1, wherein the thermocycling unit
A heat exchanger (310) for exchanging heat of the high temperature generated in the fuel cell unit with fresh water and supplying the heated fresh water to the intermediate pressure buffer unit; And
And an inverter (320) for converting the direct current power produced by the fuel cell unit into an alternating current. 3. The method of claim 2,
Pressure buffer unit to vaporize the liquefied natural gas and cool the cooled fresh water to circulate through the inverter, cool the inverter, and then supply the heat to the heat exchanger. The apparatus of claim 1, wherein the intermediate pressure buffer unit
A pump 110 installed in the hull and pumping the liquefied natural gas supplied from the LNG storage tank and transferring the liquefied natural gas to the intermediate pressure tank in an intermediate pressure state;
A vaporizer (130) for vaporizing the liquefied natural gas stored in the intermediate pressure tank; And
And a valve (140) provided in a buffer connection channel connecting the vaporizer and the fuel cell unit and opening and closing the buffer connection channel. The LNG storage tank according to claim 4, wherein the liquefied natural gas passed through the medium pressure heat exchanger is introduced into the fuel cell unit when it is vaporized by heat exchange with the buffer evaporation gas, and is recovered to the LNG storage tank when it is in a liquid state , Thermal circulation system of ship equipped with fuel cell. 6. The apparatus of claim 5,
A sensor 160 provided in a connection passage connecting the LNG storage tank and the fuel cell unit and detecting whether evaporative gas generated in the LNG storage tank is supplied to the connection passage; And
And a controller for opening / closing the valve by a signal sensed by the sensor. The fuel cell system according to claim 1, wherein the fuel cell unit
A humidifier (210) for humidifying the evaporation gas supplied from the LNG storage tank or the intermediate pressure buffer unit;
A reformer 220 for reforming the evaporated gas into hydrogen and carbon dioxide;
A fuel cell 230 generating electricity by electrochemically reacting the hydrogen supplied to the anode and the oxygen supplied from the cathode with the carbon dioxide;
A blower (240) for supplying external air to the fuel cell; And
And an air heater (250) for heating the air supplied to the fuel cell through the blower. In a fuel supply method for a marine fuel cell using a boil-off gas supplied from an LNG storage tank of a hull,
1) storing a part of the liquefied natural gas stored in the LNG storage tank in a medium pressure liquid state in an intermediate pressure tank; And
2) supplying the vaporized liquefied natural gas to the fuel cell when the supply of the evaporative gas from the LNG storage tank to the fuel cell is interrupted,
The liquefied natural gas at a medium pressure is vaporized into water heated by exhaust gas generated from a humidifier which mixes natural gas and water vapor and supplies the mixed gas to the fuel cell,
Wherein the buffer evaporation gas generated in the intermediate pressure tank is liquefied by heat exchange with the liquefied natural gas supplied from the LNG storage tank. 9. The method of claim 8,
And the cooled water is supplied as a refrigerant to an inverter for converting DC power produced in the fuel cell into AC power.

Images