KR100729056B1 - Fuel cell system having fluid supply apparatus - Google Patents

Abstract

The present invention relates to a fuel cell system having a fluid supply device, comprising: an electricity generating unit generating electricity by an electrochemical reaction between hydrogen and oxygen in a reformed gas; A reformer for supplying the reformed gas to the electricity generating unit; A fuel supply container for supplying hydrogen-containing compressed fuel to the reformer; An air supply unit supplying an oxygen-containing gas to the electricity generation unit; A water tank for supplying water to the reformer; Compression stored in a container of a predetermined size because the fuel supply container and the water tank is made of an auxiliary container provided to enable fluid communication to apply the vapor pressure of the compressed fuel flowing from the fuel supply container to the water tank By maintaining the supply amount of fuel different from the water tank and the reformer, it is possible to stably supply water from the water tank to the reformer without improving the reforming efficiency in the reformer, thereby improving the power generation efficiency of the fuel cell.

Auxiliary vessel, steam pressure, vaporizer, water tank

Description

FUEL CELL SYSTEM HAVING FLUID SUPPLY APPARATUS}

1 is a schematic diagram of a fuel cell system according to the present invention;

2 is a schematic diagram of a fuel cell system in which a vaporizer is installed in front of a reformer;

3 is a block diagram of a raw material supply apparatus according to a conventional embodiment.

<Description of Symbols for Major Parts of Drawings>

110: fuel supply container

112: heating member

114: three-phase valve

120: electricity generating unit

130: air supply

140: reformer

150: water tank

160: auxiliary container

170: carburetor

[Patent Document 1] Japanese Patent Publication No. 2003-277012

The present invention relates to a fuel cell system having a fluid supply device for supplying water stored in a water tank to a reformer by using a vapor pressure of compressed fuel, and more specifically, a pressure applied to the water tank and the reformer by the vapor pressure of the compressed fuel. The present invention relates to a fuel cell system having a fluid supply device capable of smoothly supplying compressed fuel to a reformer by forming different sizes.

In general, interest in fuel cell systems that generate electricity by electrochemically reacting hydrogen obtained from hydrocarbon fuels such as natural gas and hydrogen-containing fuels such as methanol and oxygen in the air as a solution to environmental or resource problems. This has been concentrated.

A fuel cell system is a power generation device that generates electricity by an electrochemical reaction between a hydrogen-containing fuel and oxygen as an oxidant. Such a fuel cell system basically has a power generation unit for generating electricity. The power generation unit has an electrolyte membrane having selective ion permeation characteristics, and a unit cell having an electrode membrane assembly composed of an anode electrode and a cathode electrode provided on both surfaces of the electrolyte membrane.

The fuel cell system includes a phosphoric acid fuel cell (PAFC), a molten carbonate fuel cell (MCFC), and a solid oxide fuel cell (SOFC) depending on the type of electrolyte used. ), Polymer electrolyte membrane fuel cells (PEMFC), alkaline fuel cells (AFC), and the like. Among these fuel cell systems, polymer electrolyte fuel cells have recently been widely developed and researched for the use of portable generators because of their excellent output characteristics, low operating temperature, and fast startup and response characteristics.

The polymer electrolyte fuel cell has a reformer for generating a reformed gas mainly containing hydrogen to be supplied to a unit cell. Hydrogen-containing fuel and water are supplied to the reformer to carry out the reforming reaction in the reformer. When a water pump is used to supply water to the reformer, the noise of the operation of the water pump lowers the reliability of the fuel cell system.

Meanwhile, a method of using compressed fuel as a fuel supply source of a fuel cell has been studied. When compressed fuel is used, the noise of the fuel pump is eliminated. In addition, a structure in which compressed water is used to supply water from the water tank to the reformer to omit the water pump has also been studied. As a result, when the compressed fuel is used as a fuel supply source of the fuel cell, the fuel pump and the water pump are unnecessary, thereby reducing noise and improving the reliability of the fuel cell.

For example, referring to Japanese Patent Laid-Open No. 2003-277012, a raw material supply device (see Fig. 3) in which city gas supplied through a supply pipe is supplied to a reformer via a water raw material storage container is shown. . That is, while the water of the water raw material storage container is supplied to the reformer by the pressure of the city gas, the city gas is supplied to the reformer through a bypass path formed on the side of the water raw material storage container.

When the compressed fuel is a high-pressure city gas, the same pressure is continuously applied to the reformer and the water raw material storage container, thereby improving the power generation efficiency of the fuel cell. However, when compressed fuel is stored in a container of a predetermined size, since compressed fuel is supplied to a water tank, the supply state of the compressed fuel supplied to the reformer may be poor, which causes a problem of lowering the reliability of the fuel cell. .

The present invention has been proposed to solve the conventional problems as described above, when using a compressed fuel stored in a storage container of a predetermined size as a fuel supply source of water stored in the water tank by such compressed fuel It is an object of the present invention to provide a fuel cell system having a fluid supply device capable of smoothly supplying compressed fuel to a reformer while smoothly supplying the reformer.

In order to achieve the above object, according to the present invention, the fuel cell system includes an electricity generating unit for generating electricity by the electrochemical reaction of hydrogen and oxygen of the reformed gas; A reformer for supplying the reformed gas to the electricity generating unit; A fuel supply container for supplying hydrogen-containing compressed fuel to the reformer; An air supply unit supplying an oxygen-containing gas to the electricity generation unit; A water tank for supplying water to the reformer; It characterized in that the auxiliary container provided between the fuel supply container and the water tank provided with fluid communication to apply the vapor pressure of the compressed fuel flowing from the fuel supply container to the water tank.

The fuel supply container is connected to the auxiliary container and the reformer through a branch pipe, and a branch of the branch pipe is provided with a three-phase valve. Compressed fuel is selectively supplied from the fuel supply container to the auxiliary container or reformer according to the open / closed state of the three-phase valve.

And a heating member for heating the fuel supply container or a vaporizer for vaporizing the compressed fuel so that gaseous compressed fuel can be supplied to the reformer from the fuel supply container.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

1 is a schematic diagram of a fuel cell system according to the present invention, and FIG. 2 is a schematic diagram of a fuel cell system according to an embodiment of the present invention.

Referring to FIG. 1, a fuel cell system includes an electricity generator 120 that generates electricity through an electrochemical reaction between hydrogen and an oxidant, and a reformer that supplies reformed gas having hydrogen as a main component to the electricity generator 120. 140, the air supply unit 130 for supplying the oxygen-containing gas to the electricity generating unit 120, and the hydrogen-containing fuel to be supplied to the reformer 140, that is, the fuel containing the compressed fuel mainly composed of hydrogen It has a supply unit 110.

Some of the hydrogen-containing fuel stored in the fuel supply unit 110 flows into the reformer 140 as reformed fuel, and another portion of the hydrogen-containing fuel flows into the heat source of the reformer 140 as combustion fuel, for example, a combustion unit. do. The oxygen-containing gas may be supplied to the combustion unit from the air supply unit 130 so that the combustion fuel may be combusted in the combustion unit.

The reformer 140 may include a reforming reaction unit (not shown) for generating a reformed gas having a hydrogen component as a main component from the reformed fuel supplied from the fuel supply unit 110, and the reforming reaction unit may be in fluid communication with the reforming gas. CO removal unit (not shown) for removing the carbon monoxide contained.

The reforming reaction unit is provided with a reforming catalyst (not shown). The reforming reaction unit reforms the reformed fuel using, but not limited to, steam reforming (SR), autothermal reforming (ATR), and partial oxidation (POX). The partial oxidation method and the autothermal reforming method have excellent response characteristics due to initial start-up and load variation, while the steam reforming method has an advantage in terms of hydrogen production efficiency.

In the steam reforming method, a reformed gas containing hydrogen as a main component is obtained by chemical reaction of reformed fuel and steam on the reforming catalyst, that is, endothermic reaction. In such steam reforming, a large amount of energy is required from the outside to perform the endothermic reaction, but since the reformed gas supply is stable, a relatively high concentration of hydrogen can be obtained.

Therefore, in the reformer 140, when the reforming reaction unit employs, for example, steam reforming, water is required to reform a part of the hydrogen-containing fuel supplied from the fuel supply unit 110, that is, the reformed fuel. do. The reformer 140 is fluidly connected to the water tank 150 so that water is introduced from the water tank 150.

The water tank 150 is connected to the fuel supply container 110 to enable fluid communication. Therefore, the water stored in the water tank 150 is supplied to the reformer 140 by the vapor pressure of the compressed fuel supplied from the fuel supply container 110. Preferably, the front end of the water tank 150 is provided with an auxiliary container 160 for storing the compressed fuel. More preferably, the auxiliary container 160 is supplied with the compressed fuel in a liquid state from the fuel supply container 110. This is to allow a relatively large vapor pressure to be applied to the water tank 150 by vaporizing the liquid compressed fuel stored in the auxiliary container 160.

The fuel supply container 110 is maintained in an inverted state so that compressed liquid fuel can be supplied to the auxiliary container 160. That is, when the fuel supply container 110 is filled with a liquid compressed fuel, for example, a request fuel, part of the liquid butane fuel is vaporized to be maintained as a compressed gas in the gas phase. As the compressed gas in the gas phase increases, the internal pressure of the fuel supply container 110 increases, and when this internal pressure reaches a predetermined pressure, a saturated vapor pressure state in which the liquid butane fuel is no longer vaporized is maintained.

Under this saturated vapor pressure, the action of gravity causes the liquid compressed fuel to be located at the bottom while the compressed fuel in the gas phase is located at the top. When the nozzle for discharging the compressed fuel stored in the fuel supply container 110 is located at the upper portion, the compressed fuel in the gas phase is discharged relatively easily through the nozzle, and this state is referred to as a normal state for convenience of description. However, if the nozzle of the fuel supply container 110 is located at the bottom, the compressed liquid of the liquid is relatively easily discharged through the nozzle and this state is called an inverted state.

When the fuel supply container 110 is maintained in an inverted state, the compressed liquid fuel discharged through the nozzle of the fuel supply container 110 flows into the auxiliary container 160. Inside the auxiliary container 160, the compressed liquid fuel is vaporized to increase the vapor pressure P of the compressed fuel. This steam pressure (P) is applied to the water tank 150, water is supplied from the water tank 150 to the reformer 140.

The fuel supply container 110 is preferably connected to the auxiliary container 160 and the reformer 140 to enable fluid communication through branch pipes. The branch of the branch pipe is provided with a three-phase valve 114. At this time, the compressed fuel is selectively supplied from the fuel supply container 110 to the auxiliary container 160 or the reformer 140 by controlling the open / close state of the three-phase valve 114. For example, the compressed fuel is discharged from the fuel supply container 110 in the first open state of the three-phase valve 114, that is, the opening of the reformer 140 is closed while the opening of the auxiliary container 160 is opened. The auxiliary container 160 is supplied. On the contrary, the compressed fuel is discharged from the fuel supply container 110 while the second opening / closing state of the three-phase valve 114, that is, the opening of the reformer 140 is opened while the opening of the auxiliary container 160 is closed. 140).

A controller (not shown) for controlling the open / close state of the three-phase valve 114 is provided.

When the compressed liquid fuel is supplied to the reformer 140 in the second open / closed state of the three-phase valve 114 described above, the reforming efficiency of the reformer 140 is lowered. Therefore, a vaporizer 170 for vaporizing liquid compressed fuel is provided between the branch of the branch pipe and the reformer 140 or heated around the fuel supply member 110 to heat the fuel supply container 110. Member 112 may be provided.

In the first open / closed state of the three-phase valve 114, when a predetermined amount of liquid compressed fuel is supplied to the auxiliary container 160, the three-phase valve 114 is switched to the second open / closed state. Thereafter, the vapor pressure P of the compressed fuel generated by vaporizing the liquid compressed fuel in the auxiliary container 160 is applied to the water tank 150 so that the water in the water tank 150 is supplied to the reformer 140. Compressed fuel of the fuel supply container 110 is supplied to the reformer 140.

In the reformer 140, as described above, the compressed fuel is reformed through steam reforming reaction in the reforming catalyst together with the water supplied from the water tank 150, resulting in reformed gas mainly composed of hydrogen. .

The above reformed gas also produces trace amounts of carbon dioxide, methane gas and carbon monoxide in addition to hydrogen and water vapor. Carbon monoxide, in particular, poisons the platinum catalyst generally used as an electrode of the electricity generating unit 120, and thus, it is necessary to remove the performance of the fuel cell system.

The CO removal unit includes a water gas conversion unit (not shown) and a selective oxidation unit (not shown) in which a water gas conversion catalytic reaction and a selective oxidation catalytic reaction are respectively performed to remove carbon monoxide. The water gas conversion unit is provided with a shift catalyst (not shown), and the selective oxidation unit (not shown) is provided with an oxidation catalyst (not shown). The oxygen-containing air necessary for the selective oxidation reaction is supplied to the selective oxidation unit by the air supply unit 130.

This reformed gas is supplied to the electricity generating unit 120.

The electricity generating unit 120 includes an electrode film assembly 120a (MEA) including a conductive polymer film 122 having selective ion permeability and an anode electrode 124 and a cathode electrode 126 provided on both surfaces of the conductive polymer film 122, respectively. It has a unit cell having a. The unit cell also provides a separator plate 128 provided to face the anode electrode 124 and the cathode electrode 126 so as to supply the reformed gas flowing from the reformer 140 and the oxygen flowing from the air supply 130. It includes. The separator plate 128 is provided with a flow channel 128a through which hydrogen-containing fuel or oxygen can flow, and a refrigerant flow channel 128b through which a coolant such as coolant flows.

In the electricity generating unit 120, electricity is generated by the electrochemical reaction of hydrogen and oxygen of the reformed gas. This electrochemical reaction produces by-products such as water vapor. The water vapor flows into the water tank 150 through an inlet conduit for fluid communication between the electricity generating unit 120 and the water tank 150. The inlet conduit is provided with a check valve 152 for preventing the water stored in the water tank 150 is discharged to the electricity generating unit 120 side.

Hereinafter, the operation of the fuel cell system according to the present invention will be described.

When the fuel cell system starts to operate, the three-phase valve 114 is maintained in a first open / closed state so that compressed liquid fuel is supplied from the fuel supply container 110 to the auxiliary container 160. When a predetermined amount of compressed fuel is stored in the auxiliary container 160, the three-phase valve 114 is switched from the first open / closed state to the second open / closed state such that the compressed fuel is supplied from the fuel supply container 110 to the reformer 140. do. When the three-phase valve 114 is switched to the second open / closed state, the heating member 112 or the vaporizer 170 is operated to supply the compressed gas of the gaseous phase from the fuel supply container 110 to the reformer 140.

The vapor pressure P generated by vaporizing the liquid compressed fuel in the auxiliary container 160 is applied to the water tank 150, and the water stored in the water tank 150 is supplied to the reformer 140.

In the reformer 140, a reformed gas containing hydrogen as a main component is produced by reforming the gaseous compressed fuel flowing from the fuel supply container 110 together with the water flowing from the water tank 150. The reformed gas from which carbon monoxide is removed from the CO remover 140 of the reformer 140 is supplied to the electricity generator 120.

In the electricity generating unit 120, hydrogen of the reformed gas supplied from the reformer 140 and oxygen supplied from the air supply unit 130 perform an electrochemical reaction, and as a result, electricity is generated. Water vapor generated as a result of the above-described electrochemical reaction is recycled by being introduced into the water tank 150 through the inlet conduit and condensed.

The foregoing is merely illustrative of preferred embodiments of the present invention and those skilled in the art to which the present invention pertains may make modifications and changes to the present invention without departing from the spirit and gist of the invention as set forth in the appended claims. It should be recognized.

According to the present invention, the supply amount of compressed fuel stored in a container of a predetermined size is kept different from the water tank and the reformer, thereby stably supplying water from the water tank to the reformer without lowering the reforming efficiency in the reformer, thereby improving the fuel cell power generation efficiency. Can improve.

Claims (8)

An electricity generator which generates electricity by an electrochemical reaction between hydrogen and oxygen of the reformed gas; A reformer for supplying the reformed gas to the electricity generating unit; A fuel supply container for supplying hydrogen-containing compressed fuel to the reformer; An air supply unit supplying an oxygen-containing gas to the electricity generation unit; A water tank for supplying water to the reformer; And an auxiliary container provided to enable fluid communication between the fuel supply container and the water tank so as to apply the vapor pressure of the compressed fuel flowing from the fuel supply container to the water tank. The method of claim 1, And a branch pipe for connecting the fuel supply container to the auxiliary container and the reformer, wherein the branched portion of the branch pipe includes a three-phase valve-compressed fuel from the fuel supply container according to the open / closed state of the three-phase valve. Or supplied to the reformer. The method of claim 2, And a heating member for heating the fuel supply container. The method of claim 2, And a vaporizer provided to vaporize the compressed fuel between the branch of the branch pipe and the reformer. The method of claim 2, The fuel cell system, characterized in that the compressed fuel of the liquid supply to the auxiliary container from the fuel supply container. The method of claim 5, The fuel supply container is characterized in that the fuel cell system is provided in an inverted state in which the nozzle for discharging the compressed fuel is located below. The method of claim 1, The fuel cell system further comprises an inlet conduit for introducing water vapor generated by the electrochemical reaction in the electricity generating unit into the water tank. The method of claim 7, wherein The inlet conduit is provided with a check valve for blocking the inflow of water from the water tank to the electricity generating unit.

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