JP2008117562A - Fuel cell system and its operation control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell system capable of stably efficiently operating by using liquid fuel as a raw material. <P>SOLUTION: When supply of liquid fuel 111A desufurized with a desufurization means 120 to a vaporization means 130 is stopped to stop operation, inert gas is supplied to the downstream side than the desulfurization means 120 with an inert gas supply means 180, inert gas flowing out of a fuel cell 170 by the supply of the inert gas is supplied to the downstream side than the desulfurization means 120 with a circulation means 190 connected to the fuel cell 170. Since inert gas for purging is circulated, the used amount of the inert gas for purging can be reduced and efficient operation is made possible. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a fuel cell system that generates power in a fuel cell using liquid fuel as a raw material, and an operation control method thereof.

Conventionally, a fuel cell system that supplies hydrogen gas as a fuel gas to a fuel cell to generate electric power is known. As these fuel cell systems, a configuration in which reformed gas or the like is purged when the system is started / stopped is known (see, for example, Patent Documents 1 to 3).
In Patent Document 1, a part of the reformed gas is guided to the hydrogen storage alloy through the reformed gas line during the operation of the reformer, and only hydrogen is absorbed, and the hydrogen storage is performed when the reformer is stopped. A configuration is adopted in which hydrogen is released from the alloy, hydrogen is supplied to the upstream side of the reformer through the hydrogen gas line, residual fuel and moisture in the reformer are purged, and hydrogen is sealed in the reformer. It has been.
When the system is stopped, the one described in Patent Document 2 closes the valve of the outlet conduit of either the CO conversion unit and the CO removal unit sequentially connected to the steam reformer including the combustion unit and the reforming unit, and reforms. The supply of raw material gas and water to the department is stopped. Then, when the reforming section and the CO conversion section are below a predetermined temperature at which the hydrocarbon decomposition reaction does not proceed and carbon is not deposited due to the decomposition reaction, the valve is opened and the raw material gas is supplied into the system. To purge the reformed gas. Thereafter, the valve is closed and the system is filled with the raw material gas.
Patent Document 3 describes a method in which steam is circulated in a reformer system to purge combustible gas, and then the temperature of the reforming catalyst in the reformer is an oxidation temperature of the reforming catalyst. A configuration is adopted in which air is introduced into the reformer and the water vapor in the reformer system is purged when the temperature falls to or below.

JP 2000-21431 A JP 2004-307236 A JP 2002-8701 A

However, in the configuration of purging with the conventional hydrogen gas as described in Patent Document 1, a special configuration using an expensive hydrogen storage alloy and pressure control for storing and releasing hydrogen at the time of operation and stop, etc. Complicated control is required, and particularly in the case of use at home, a small and inexpensive system configuration is required to expand use.
Further, in the configuration in which the reformed gas is purged as described in Patent Document 2, the purged reformed gas is discharged as it is at the time of restart. For example, in the case of a system that stops every day, the purge is performed. The amount of the reformed gas that is used and discharged becomes large, and more efficiency is desired from the viewpoint of energy efficiency.
Further, in the configuration of purging air as described in Patent Document 3, there is a possibility that the reforming catalyst may be gradually deactivated by oxygen in the air even at a temperature of 350 ° C. or lower, and the reforming characteristics are deteriorated. Efficiency may be reduced.

  In view of the above, an object of the present invention is to provide a fuel cell system capable of operating stably and efficiently using liquid fuel as a raw material, and an operation control method thereof.

A fuel cell system according to the present invention includes a desulfurization unit that desulfurizes liquid fuel, a vaporization unit that vaporizes the liquid fuel desulfurized by the desulfurization unit, and a reforming that reforms the source gas into a fuel gas. Means, oxygen-containing gas supply means for supplying oxygen-containing gas, fuel gas reformed by the reforming means, and fuel that generates electric power using the oxygen-containing gas supplied by the oxygen-containing gas supply means A battery, an inert gas supply means for supplying an inert gas downstream from the desulfurization means when the supply of the liquid fuel desulfurized by the desulfurization means to the vaporization means is stopped and operation is stopped, and the fuel A circulation means connected to a battery and supplying the effluent flowing out of the fuel cell to the downstream side of the desulfurization means when the inert gas is supplied by the inert gas supply means. It is characterized in.
In this invention, the raw material gas after desulfurizing the liquid fuel by the desulfurization means and vaporizing by the vaporization means is reformed to the fuel gas by the reforming means, and the oxygen-containing gas supplied by the oxygen-containing gas supply means and the fuel cell In the system configuration in which power is generated by reacting with the desulfurization means, when the supply of the liquid fuel desulfurized by the desulfurization means is stopped and the operation is stopped, the inert gas supply means supplies the inert gas downstream from the desulfurization means. The effluent flowing out of the fuel cell by supplying the inert gas is supplied downstream from the desulfurization means by the circulation means connected to the fuel cell.
As a result, the inert gas is circulated by being supplied downstream from the desulfurization means by the circulation means in a state where the inert gas is supplied and the inert gas flows out from the fuel cell as an effluent. There is no need to supply the inert gas, it is sufficient to supply the inert gas at a minimum, and the inert gas can be reused with a simple configuration in which the supplied inert gas is returned, and the inert gas is stable. Thus, an efficient operation stop purge can be obtained, and an efficient operation can be provided.

And in this invention, it is preferable that the said circulation means is set as the structure provided with the storage means which stores the effluent which is connected to the said fuel cell and flows out of the said fuel cell.
In this invention, the storage means for storing the effluent is provided in the circulation means that is connected to the fuel cell and supplies the effluent flowing out from the fuel cell downstream from the desulfurization means.
For this reason, for example, when inert gas is supplied in a somewhat excessive amount for purging with an inert gas, the surplus is recovered by the storage means, or the inert gas remaining at the time of restarting is circulated to the circulation means. More effective use of the inert gas such as recovery by the storage means can be obtained, and more efficient operation control can be obtained.

In the present invention, it is preferable that the circulation means includes a gas-liquid separation means for gas-liquid separation of the effluent, and the separated gas is supplied downstream from the desulfurization means.
In this invention, the gas-liquid separation means for separating the effluent from gas and liquid is provided in the circulation means, and the separated gas is supplied downstream from the desulfurization means.
As a result, for example, water at the time of power generation that flows out as effluent by supplying inert gas and purging, water derived from water vapor for vaporization of liquid fuel, and the like are separated and removed, and dry inert gas is removed. Circulation is easily obtained with a simple configuration, and it is possible to prevent a reduction in the reforming capacity of the reforming means due to the return of water, and a good stop state can be easily obtained.

Further, in the present invention, the vaporizing means mixes the heat exchange device that generates steam by exhaust from the reforming means, and the liquid fuel desulfurized by the desulfurization means, the steam generated by the heat exchange device. A vaporizer that vaporizes the source gas, and the gas-liquid separation means supplies the liquid phase fraction collected by gas-liquid separation of the effluent to the heat exchange device to generate the water vapor. It is preferable.
In the present invention, as the vaporizing means, steam is generated by the heat exchange device by exhaust from the reforming means, and the water vapor is mixed with the liquid fuel desulfurized by the desulfurizing means and vaporized to vaporize the raw material gas. The liquid phase fraction collected by gas-liquid separation of the effluent by the gas-liquid separation means of the means, that is, water derived from water vapor is supplied to the heat exchanging device to generate water vapor that vaporizes the liquid fuel.
As a result, water that is a raw material for water vapor for efficiently generating hydrogen gas that is mixed with liquid fuel and generated by a fuel cell is recovered well, a good water balance is obtained, and more efficient operation is achieved. Is obtained.

In the present invention, the inert gas supply means supplies the inert gas for a predetermined time length when the supply of the liquid fuel desulfurized by the desulfurization means to the vaporization means is stopped. It is preferable that the inert gas is re-supplied when the supply of water vapor from the heat exchange device to the vaporizer in the vaporization means is stopped after a predetermined time has elapsed after the supply of the active gas for a predetermined length of time.
In this invention, the inert gas supply means causes the inert gas to be supplied for a predetermined time after the supply of the liquid fuel desulfurized by the desulfurization means is stopped, and after the predetermined time has elapsed, the heat exchange device in the vaporization means to the vaporizer When the supply of water vapor is stopped, the inert gas is supplied again.
This prevents inconvenience such as carbonization due to the liquid fuel or the gas derived from the liquid fuel remaining in the reforming means by purging with the inert gas after the supply of the liquid fuel is stopped. For example, by supplying the reforming means with steam supplied by the vaporization means to reform the liquid fuel, the reforming means can be cooled quickly, and the reforming means cools to a certain degree to The inert gas is re-supplied after a predetermined time, such as before the water is deposited as water, and the water vapor is deposited as water due to the remaining water vapor to prevent inconveniences such as deterioration of the reforming characteristics, and it is quick and efficient. The operation can be stopped.

In the present invention, the inert gas supply means supplies the inert gas upstream from the vaporization means and downstream from the desulfurization means.
In the present invention, the inert gas is supplied upstream of the vaporization means and downstream of the desulfurization means by the inert gas supply means.
This prevents, for example, the liquid fuel from remaining when the supply of the liquid fuel is shut off in order to stop the operation at a portion upstream from the vaporization means through which the liquid fuel flows in the liquid phase. It is possible to prevent inconveniences such as carbonization due to residual heat of the reforming means.

In the present invention, the inert gas supply means supplies the inert gas to the downstream side of the desulfurization means and also supplies the downstream side of the reforming means to the upstream side of the fuel cell. It is preferable.
In the present invention, the inert gas supply means supplies the inert gas to the downstream side of the desulfurization means and also supplies the downstream side of the reforming means to the upstream side of the fuel cell.
As a result, for example, a region on the downstream side of the reforming unit that does not cause inconvenience even if water derived from water vapor precipitates, and a region on the reforming unit side that causes inconvenience such as deterioration of reforming characteristics due to water remaining. In addition, a configuration in which an inert gas is supplied independently is obtained, and the inert gas is re-supplied to discharge water vapor only on the region side where water vapor is supplied to the reforming means for rapid cooling in the reforming means. The amount of inert gas used can be further reduced, and more efficient operation can be obtained.

Further, in the present invention, the reforming means includes a burner for heating to reform the raw material gas vaporized by the vaporization means, and the effluent flowing from the fuel cell connected to the fuel cell is removed. It is preferable that return means for supplying the burner to burn is provided, and the circulation means is connected to the fuel cell via the return means.
In the present invention, the recirculation means is connected to the burner that is heated to reform the raw material gas vaporized by the vaporization means in the reforming means, and the return means that is connected to the fuel cell and flows out from the fuel cell to burn it. The means is connected to supply the effluent to the downstream side of the desulfurization means.
As a result, for example, the supply of liquid fuel is stopped and hydrogen gas or carbon monoxide, which is an effluent flowing out of the fuel cell by purging with an inert gas, is burned with a burner to improve energy efficiency and protect the environment. After the steam is supplied to the reforming means for rapid cooling, the steam and inert gas components flowing out of the fuel cell are recovered by the circulation means by purging the inert gas, and the steam is separated and removed to be inert. A configuration in which only the gas is supplied and circulated can be easily obtained, and a good and efficient operation can be easily obtained with a simple configuration in which the return means is branched.

Further, in the present invention, the burner burns and heats the liquid fuel, and the inert gas supply means supplies the inert gas also to a path for supplying the liquid fuel to the burner. It is preferable to do.
In the present invention, the inert gas is also supplied to the path for supplying the liquid fuel burned by the burner to the burner for heating in the reforming means.
As a result, when the operation is stopped, the supply of the liquid fuel is stopped and the heating by the burner is stopped, so that the liquid fuel remaining in the path for supplying the liquid fuel to the burner is carbonized by the residual heat of the reforming means. Can be prevented, and stable and good operation can be obtained.

The operation control method for a fuel cell system according to the present invention is an operation state in a fuel cell system in which liquid fuel is desulfurized by a desulfurization means and then vaporized as a raw material gas by a vaporization means and then reformed by a reforming means and then supplied to the fuel cell to generate power. An operation control method of a fuel cell system for controlling a desulfurization fuel path having a desulfurization fuel valve for supplying the liquid fuel from the desulfurization means to the vaporization means, and supplying an inert gas downstream from the desulfurization means And an inert gas supply means that circulates the effluent that is connected to the fuel cell and flows out of the fuel cell to the downstream side of the desulfurization means, and switches the desulfurization fuel valve to the vaporization from the desulfurization means. A fuel supply shutoff step for shutting off the supply of the liquid fuel to the means, and the inertness after shutting off the liquid fuel supply in the fuel supply shutoff step An inert gas purge step for supplying the inert gas from the gas supply means to the downstream side of the desulfurization means, and the inert gas is supplied in the inert gas purge step to flow out of the fuel cell through the circulation means. And a circulation step of supplying the effluent to be supplied downstream from the desulfurization means.
In this invention, a desulfurization fuel path having a desulfurization fuel valve for supplying liquid fuel from the desulfurization means to the vaporization means in the fuel cell system, an inert gas supply means for supplying an inert gas downstream from the desulfurization means, and a fuel Circulating means connected to the battery and supplying the effluent flowing out from the fuel cell downstream from the desulfurization means is used. Then, after performing the fuel supply blocking step of switching the desulfurization fuel valve to block the supply of liquid fuel from the desulfurization means to the vaporization means, the inert gas supply means is configured to supply the inert gas downstream from the desulfurization means. An active gas purge step is performed. By supplying the inert gas in this inert gas purging step, a circulation step is performed in which the effluent flowing out from the fuel cell is supplied downstream from the desulfurization means via the circulation means.
As a result, the inert gas is circulated by being supplied downstream from the desulfurization means by the circulation means in a state where the inert gas is supplied and the inert gas flows out from the fuel cell as an effluent. There is no need to supply the inert gas, it is sufficient to supply the inert gas at a minimum, and the inert gas can be reused with a simple configuration in which the supplied inert gas is returned, and the inert gas is stable. Thus, an efficient operation stop purge can be obtained, and an efficient operation can be provided.

And in this invention, it is preferable that the said circulation process sets it as the structure which gas-liquid-separates the said effluent which flows out from the said fuel cell, and supplies a gaseous-phase part downstream from the said desulfurization means.
In the present invention, in the circulation step, the effluent flowing out from the fuel cell is gas-liquid separated to supply the gas phase component downstream from the desulfurization means.
As a result, for example, water at the time of power generation that flows out as effluent by supplying inert gas and purging, water derived from water vapor for vaporization of liquid fuel, and the like are separated and removed, and dry inert gas is removed. Circulation is easily obtained with a simple configuration, and it is possible to prevent a reduction in the reforming capacity of the reforming means due to the return of water, and a good stop state can be easily obtained.

In the present invention, the inert gas purge step includes a first purge step of supplying the inert gas from the inert gas supply means to the downstream side of the desulfurization means for a predetermined time after the supply of the liquid fuel is shut off. A second purge step of supplying the inert gas from the inert gas supply means downstream of the desulfurization means after a predetermined time has elapsed after supplying the inert gas for a predetermined time in the first purge step; It is preferable that the configuration be implemented.
In the present invention, as the inert gas purge process, after the liquid fuel supply is shut off, the first purge process is performed in which the inert gas is supplied from the inert gas supply means to the downstream side of the desulfurization means for a predetermined time. Then, a second purge step is performed in which the inert gas is re-supplied downstream from the desulfurization means from the inert gas supply means.
This prevents inconvenience such as carbonization due to the liquid fuel or the gas derived from the liquid fuel remaining in the reforming means in the inert gas purge in the first purge step after the supply of the liquid fuel is stopped, The supply of the inert gas is temporarily interrupted, and for example, by supplying the reforming means with steam supplied by the vaporization means to reform the liquid fuel, the reforming means can be quickly cooled. The inert gas is re-supplied in the second purge step after a predetermined time elapses, for example, after cooling to a certain degree and before water vapor is precipitated as water, and the water vapor is deposited as water due to the remaining water vapor, resulting in a problem such as deterioration in reforming characteristics. Can be prevented, and the operation can be stopped quickly and efficiently.

Furthermore, in the present invention, it is preferable that the circulation step is configured to supply the effluent flowing out from the fuel cell in the second purge step to the downstream side from the desulfurization means.
In the present invention, in the circulation step, the effluent flowing out from the fuel cell in the second purge step is supplied downstream from the desulfurization means.
Thus, since the effluent flowing out of the fuel cell by supplying the inert gas in the second purge step is water vapor or a mixed gas of water vapor and inert gas, by removing only water vapor and supplying it, Without returning water, the amount of inert gas used is minimized, resulting in more efficient operation.

Hereinafter, an embodiment according to the fuel cell system of the present invention will be described.
In the present embodiment, the configuration of a fuel cell system that uses kerosene is exemplified, but the present invention can be applied to, for example, a manufacturing apparatus that manufactures fuel gas supplied to a fuel cell.
FIG. 1 is a block diagram showing a schematic configuration of a fuel cell system according to the present embodiment.

[Configuration of fuel cell system]
(overall structure)
In FIG. 1, reference numeral 100 denotes a fuel cell system. The fuel cell system 100 is a system that uses liquid fuel as a raw material to be reformed into a fuel gas containing hydrogen as a main component and causes the fuel cell 170 to generate electric power.
The fuel cell system 100 includes a liquid fuel supply means 110, a desulfurization means 120, a vaporization means 130, a reforming means 140, an oxygen-containing gas supply means 150, a humidifier 160, a fuel cell 170, an inert gas. A gas supply unit 180, a circulation unit 190, and the like are provided.

The liquid fuel supply unit 110 includes a liquid fuel storage tank 111 and a liquid fuel supply path 112.
The liquid fuel storage tank 111 stores liquid fuel 111A such as kerosene so that it can flow out. Here, the liquid fuel 111A is not limited to kerosene, and various liquid fuels such as light oil and naphtha can be used.
The liquid fuel supply path 112 is connected to the liquid fuel storage tank 111, and distributes the liquid fuel 111A stored in the liquid fuel storage tank 111. The liquid fuel supply path 112 includes a liquid fuel pump 112A and a fuel supply valve 112B, and includes a fuel supply pipe 112C having one end connected to the liquid fuel storage tank 111 and the other end connected to the desulfurization means 120. The liquid fuel supply path 112 distributes the liquid fuel 111A stored in the liquid fuel storage tank 111 to the desulfurization means 120 by driving the liquid fuel pump 112A.
The liquid fuel supply means 110 is not limited to the configuration provided with the liquid fuel storage tank 111. For example, the liquid fuel supply means 110 is connected to the separately provided liquid fuel storage tank 111 and stores liquid in the liquid fuel storage tank 111. It is good also as a structure provided only with the liquid fuel supply path 112 which distribute | circulates the fuel 111A.

The desulfurization means 120 includes a desulfurizer 121, a buffer tank (not shown), and the like.
The desulfurizer 121 is a sulfur containing liquid fuel 111A supplied from the liquid fuel storage tank 111 via the liquid fuel supply path 112 at, for example, about 300 [ml / hour] in the liquid fuel 111A by the liquid phase adsorption method. A desulfurization treatment is carried out to adsorb and remove the compound. The desulfurizer 121 includes a desulfurization agent container, a desulfurization heating unit, and the like, which are not illustrated. The desulfurization agent container is formed in a substantially cylindrical shape filled with a desulfurization agent, and the other end of the fuel supply pipe 112C of the liquid fuel supply path 112 is connected to one end in the axial direction so that the liquid fuel 111A flows in (not shown). It has an inflow port, and has an unillustrated outflow port for flowing out the liquid fuel 111A connected to the buffer tank and in contact with the desulfurization agent at the other end in the axial direction. The desulfurizer 121 is in a state where the axial direction of the desulfurizing agent container is substantially along the vertical direction, and the inflow port is opened downward in the vertical direction and the outflow port is opened upward in the vertical direction. Installed. That is, the desulfurizer 121 is installed in a state in which the liquid fuel 111A flows in from the lower part of the desulfurizing agent container and flows out from the upper part while flowing upward in the vertical direction. The desulfurization heating means includes, for example, an electric heater such as a sheathed heater spirally disposed on the outer surface of the desulfurizing agent container, and desulfurizes by heating the liquid fuel 111A flowing from the outer surface side of the desulfurizing agent container to about 200 ° C., for example. Promote processing. In addition, the outer surface of the desulfurizer 121 is provided with a heat insulating material that covers and heat-insulates the outer surface of the desulfurizing agent container together with the electric heater. Further, the electric heater is not limited to the spiral arrangement, and may be arranged so as to be folded back along the longitudinal direction of the desulfurization agent container, for example.
The buffer tank is a tank that temporarily stores the liquid fuel 111A desulfurized by the desulfurizer 121. The buffer tank is provided with a liquid amount sensor that detects the amount of liquid fuel 111A to be stored. This liquid amount sensor outputs a signal related to the liquid amount for controlling the driving of the liquid fuel pump 112A in the liquid fuel supply path 112 in a state where a predetermined amount is stored in the buffer tank. A desulfurization fuel path 122 having a desulfurization fuel valve 122A and a desulfurization fuel pump (not shown) is connected to the lower portion of the buffer tank, and the stored desulfurized liquid fuel 111A can be supplied to the vaporizing means 130. Yes. In addition, a combustion gas supply path (not shown) is connected to the upper part of the buffer tank so that the vaporized liquid fuel 111A is discharged, for example, supplied as combustion gas burned by the reforming means 140.

The vaporization means 130 is connected to the desulfurization fuel path 122 of the desulfurization means 120, and vaporizes the liquid fuel 111A after the desulfurization process supplied from the desulfurization means 120. The vaporization means 130 includes a vaporizer 131, a heat exchange device 132, a water supply path 133, and the like.
The vaporizer 131 is connected to the desulfurization fuel path 122 and supplied with the liquid fuel 111A, and is connected to the heat exchange device 132 and supplied with water vapor from the heat exchange device 132. The vaporizer 131 appropriately mixes the liquid fuel 111A and water vapor to vaporize, that is, generate vaporized liquid fuel that is a raw material gas. The vaporizer 131 is connected to the reforming unit 140, and supplies the vaporized liquid fuel, which is the liquid fuel 111 </ b> A vaporized by mixing water vapor, to the reforming unit 140.
The heat exchanging device 132 is connected to the reforming unit 140, cools the exhaust gas exhausted from the reforming unit 140, generates water vapor from water that exchanges heat with the exhaust gas, and supplies the generated water vapor to the vaporizer 131. Specifically, a pure water tank 133B for storing pure water 133A is connected to the heat exchanging device 132 via a water supply path 133 having a transfer pump 133C and a transfer valve 133D, and from the pure water tank 133B to the pure water 133A. Is supplied. The pure water 133A is heat-exchanged with the exhaust gas from the reforming means 140 and supplied to the vaporizer 131 as water vapor. The pure water tank 133B may be configured to store pure water 133A that does not contain impurities such as distilled water and to supply, for example, tap water or the like after being purified.

The reforming unit 140 reforms the vaporized liquid fuel vaporized by mixing the water vapor by the vaporizing unit 130 into a hydrogen-rich fuel gas. The reforming means 140 includes a reformer 141, a CO converter 142, a CO selective oxidizer 143, and the like.
The reformer 141 includes a reforming catalyst such as a nickel catalyst (not shown) and a burner 141A as a heating device. The burner 141 </ b> A is connected to a fuel transfer path 144 that is connected to the liquid fuel storage tank 111 and has a transfer pump 144 </ b> A to transfer the liquid fuel 111 </ b> A stored in the liquid fuel storage tank 111. In addition, an air supply path 145 having an air supply blower 145A and an air supply valve 145B is connected to the burner 141A, and combustion air is supplied by driving the air supply blower 145A. Further, the burner 141A is connected to a fuel cell 170, which will be described in detail later, and has an open / close valve 146A, which is connected to a fuel gas supply path 146 as a return means for discharging fuel gas which is an effluent discharged from the fuel cell 170. Has been. The burner 141A burns the fuel gas supplied via the fuel conveyance path 144 and the fuel gas supplied via the fuel gas supply path 146 with the air supplied from the air supply blower 145A, and reformed. The vaporized liquid fuel supplied to the vessel 141 is steam reformed into a hydrogen-rich fuel gas. The high-temperature exhaust gas generated by the combustion of the burner 141A is supplied to the heat exchange device 132 of the vaporizing means 130, cooled by heat exchange with the pure water 133A, and exhausted into the outside air.
The CO converter 142 converts carbon monoxide (CO) contained in the hydrogen-rich fuel gas flowing out from the reformer 141.
The CO selective oxidizer 143 is connected to the oxidation blower 143A and supplied with air. The CO selective oxidizer 143 oxidizes the remaining CO that is not transformed by the CO transformer 142 to carbon dioxide (CO ₂ ) by oxygen in the supplied air, and removes CO in the fuel gas.
Note that the CO converter 142 and the CO selective oxidizer 143 may be integrated with the reformer 141. In addition to the CO converter 142 and the CO selective oxidizer 143, a device for adsorbing and removing CO may be provided.

The oxygen-containing gas supply means 150 supplies, for example, air to the fuel cell 170 as the oxygen-containing gas.
Specifically, the oxygen-containing gas supply means 150 includes a blower 151, an air supply pipe 152 having one end connected to the blower 151 and the other end connected to the humidifier 160, and air provided in the air supply pipe 152. And a valve 153. The blower 151 is driven to supply air to the humidifier 160 through the air supply pipe 152.

The humidifier 160 has a first humidifying unit 161 and a second humidifying unit 162.
The first humidifying unit 161 is connected to the CO selective oxidizer 143 of the reforming unit 140 via the fuel gas supply path 163 having the fuel gas valve 163A, and the hydrogen-rich fuel gas reformed by the reforming unit 140 is supplied to the first humidifying unit 161. For example, it is humidified with pure water 133A supplied from, for example, a pure water tank 133B while adjusting to about 60 to 70 ° C., for example. Then, the first humidification unit 161 supplies the humidified fuel gas to the fuel cell 170.
The second humidifying unit 162 is connected to the air supply pipe 152 of the oxygen-containing gas supply means 150, and humidifies with pure water 133A supplied from the pure water tank 133B while heating the supplied air to, for example, 60 to 70 ° C. To do. Then, the second humidifying unit 162 supplies the humidified air to the fuel cell 170.
The fuel gas supply path 163 is connected to the bypass path 165 at a position upstream of the fuel gas valve 163A. The bypass path 165 has a switching valve 165A and is connected to the downstream side of the opening / closing valve 146A in the fuel gas supply path 146. The bypass path 165 supplies the fuel gas flowing through the fuel gas supply path 163 to the burner 141A of the reformer 141 via the fuel gas supply path 146.

The fuel cell 170 reacts hydrogen and oxygen to generate DC power. The fuel cell 170 is, for example, a solid polymer fuel cell, and includes a positive electrode 171, a negative electrode 172, and a polymer electrolyte membrane (not shown) disposed between the positive electrode 171 and the negative electrode 172. Then, the air humidified by the humidifier 160 is supplied to the positive electrode 171 side, and the hydrogen-rich fuel gas humidified by the humidifier 160 is supplied to the negative electrode 172 side. Then, hydrogen (fuel gas) and oxygen in the air react to generate water (pure water 133A), and DC power is generated between the positive electrode 171 and the negative electrode 172.
The negative electrode 172 side is connected to the burner 141A of the reformer 141 via the fuel gas supply path 146 as described above, and supplies the surplus hydrogen as fuel for the burner 141A. A separator 175 is connected to the positive electrode 171 side. The separator 175 is supplied with air used for the reaction from the positive electrode 171 side, and is separated into air for the gas phase and water (pure water 133A) for the liquid phase. The separated air is exhausted to the outside air. And the pure water tank 133B is connected to the separator 175, and the separated water (pure water 133A) is supplied to the pure water tank 133B.
The fuel cell 170 is provided with a cooling device 177. The cooling device 177 is provided with a heat recovery device 177 A attached to the fuel cell 170. A pure water tank 133B is connected to the heat recovery device 177A via a cooling water circulation path 178 including a cooling water circulation pump 178A and a heat exchanger 178B. The cooling device 177 drives the cooling water circulation pump 178A to circulate pure water 133A serving as cooling water between the heat recovery device 177A and the pure water tank 133B through the cooling water circulation path 178, and generates heat with power generation. The fuel cell 170 is cooled and heat is recovered. The heat exchanger 178B exchanges heat with the pure water 133A circulated and heat recovered by the heat recovery device 177A, for example, tap water. The tap water warmed by this heat exchange is directly supplied to other facilities such as a bath for effective use. In addition to heat exchange with tap water, it may be used effectively for other facilities such as generating electricity from heat obtained by heat exchange.

The inert gas supply unit 180 supplies an inert gas when the operation of the fuel cell system 100 is stopped, and replaces, fills, or purges the fuel cell system 100 with the inert gas. The inert gas supply unit 180 includes an inert gas tank 181 and an inert gas supply path 182.
The inert gas tank 181 stores, for example, nitrogen gas as an inert gas so that it can flow out. Here, the inert gas is not limited to nitrogen gas, and various inert gases such as argon gas can be used.
The inert gas supply path 182 is connected to the inert gas tank 181, distributes the inert gas stored in the inert gas tank 181, supplies it to the downstream side of the desulfurization means 120, and purges it. Specifically, the inert gas supply path 182 includes an inert gas valve 182 </ b> A, and includes an inert gas supply pipe 182 </ b> B whose upstream side is connected to the inert gas tank 181. Further, the downstream side of the inert gas supply pipe 182B is branched into a first supply pipe 182C and a second supply pipe 182D. The first supply pipe 182C has a first valve 182C1, and its downstream end is downstream of the desulfurization means 120 and upstream of the vaporizer 131 of the vaporization means 130, that is, downstream of the desulfurization fuel valve 122A in the desulfurization fuel path 122. Connected to the side. The second supply pipe 182D has a second valve 182D1, and has a downstream end connected downstream of the fuel gas valve 163A in the fuel gas supply path 163 and upstream of the first humidifier 161 of the humidifier 160. . Further, a third supply pipe 182E is connected to the first supply pipe 182C so as to be located downstream of the first valve 182C1. The third supply pipe 182E has a third valve 182E1, and stops the drive of the fuel transport path 144 downstream of the transport pump 144A and upstream of the burner 141A, particularly the transport pump 144A, and supplies the liquid fuel 111A. It is connected to the upstream side from the position where the liquid fuel 111A remains in the fuel conveyance path 144 when it stops and the heat of the reformer 141 vaporizes.

The circulation means 190 is connected to the fuel cell 170, and supplies the effluent flowing out from the fuel cell 170, that is, the fuel gas or the inert gas discharged from the fuel cell 170 to the downstream side from the desulfurization means 120. The circulation unit 190 includes a circulation path 191, a storage unit 192, and a circulation blower 193.
The circulation path 191 has a circulation valve 191 </ b> A, one end connected to the negative electrode 172 side of the fuel cell 170, that is, connected upstream from the open / close valve 146 </ b> A in the fuel gas supply path 146, and the other end downstream from the desulfurization means 120. The effluent discharged from the negative electrode 172 of the fuel cell 170 is connected to the upstream side of the first valve 182C1 in the first supply pipe 182C of the connection or inert gas supply path 182 from the vaporizer 131 on the downstream side of the desulfurization means 120. Supply upstream.
The storage unit 192 is provided in the circulation path 191 and stores the effluent that flows out from the negative electrode 172 of the fuel cell 170. The storage means 192 is provided with a gas-liquid separation means 192A. The gas-liquid separation unit 192A gas-liquid separates the effluent flowing from the negative electrode 172 through the circulation path 191 and flowing into the storage unit 192. Specifically, the gas-liquid separation unit 192A is provided in a storage tank (not shown) constituting the storage unit 192, and only water (pure water 133A) that is a liquid phase component in the effluent flows to the pure water tank 133B. A drain trap (not shown) is provided, and a vent trap that circulates only the gas phase in the effluent to the downstream side of the circulation path 191 is provided.
The circulation blower 193 is provided on the downstream side of the storage unit 192 in the circulation path 191, and supplies the gas phase component stored in the storage unit 192 to the downstream side of the desulfurization unit 120 by driving.

The fuel cell system 100 includes a control device (not shown) that controls the operation of the entire system.
This control device controls the flow rate of the liquid fuel 111A, controls the power supplied to the electric heater which is the heating condition of the desulfurization heating means of the desulfurizer 121, controls the combustion of the burner 141A of the reformer 141, and heats the steam in the heat exchanger 132. Control of supply amount of pure water 133A for generation, temperature management, management of power generation amount, purge processing of inert gas, and the like are performed.

[Operation of fuel cell system]
Next, the operation in the fuel cell system 100 described above will be described with reference to the drawings.

(Start process)
First, as an operation in the fuel cell system 100, an activation process that is an operation at the time of activation will be described with reference to FIG.
FIG. 2 is a flowchart showing the control operation of the startup process.

First, when the control device acquires a signal relating to a power generation request, it confirms that each valve is closed, that is, the fuel supply valve 112B of the liquid fuel supply path 112, the desulfurization fuel valve 122A of the desulfurization fuel path 122, and the inert gas. Inert gas valve 182A of the supply pipe 182B, first valve 182C1 of the first supply pipe 182C, second valve 182D1 of the second supply pipe 182D, circulation valve 191A of the circulation path 191, transport valve 133D of the water supply path 133, oxygen-containing gas Air valve 153 of supply means 150, air supply valve 145B of air supply path 145, opening / closing valve 146A of fuel gas supply path 146, switching valve 165A of bypass path 165, fuel gas valve 163A of fuel gas supply path 163, third supply pipe The third valve 182E1 of 182E is controlled to be closed. The signal related to the power generation request includes input operations such as a switch switching operation by the user, timer control for recognizing that the time measuring means for measuring the current time has reached a preset time, and power consumption in the power load. Examples thereof include a signal accompanying a start or an increase in power consumption, a signal accompanying a decrease in the storage amount of the reduced storage battery, and the like.
And a control apparatus implements a warm-up process (step S101).
That is, the control device operates a starting heater (not shown) to heat the burner 141A. Further, the control device opens the air supply valve 145B of the air supply path 145, drives the air supply blower 145A, and supplies combustion air to the burner 141A of the reformer 141. Further, the control device drives the cooling water circulation pump 178A of the cooling water circulation path 178 to circulate the pure water 133A stored in the pure water tank 133B through the cooling device 177, the heat exchanger 178B, and the pure water tank 133B.

After the warm-up process in step S101, the control device confirms the temperature state of burner 141A (step S102). When the controller recognizes that the burner 141A has warmed to a certain temperature, it drives the transport pump 144A in the fuel transport path 144 to supply the liquid fuel 111A stored in the liquid fuel storage tank 111 to the burner 141A. Then, the igniter (not shown) of the burner 141A is operated to burn the liquid fuel 111A to heat the reformer 141.
Further, the control device detects the flame temperature of the burner 141A. When the control device recognizes that the flame detection temperature of the burner 141A has reached a predetermined temperature (step S103), each of the reformer 141, the CO converter 142, and the CO selective oxidizer 143 of the reforming means 140 is recognized. It is detected whether the temperature has reached a predetermined temperature. Thereafter, when the control device recognizes that the reforming means 140 has reached a predetermined temperature (step S104), the control device performs the reforming process (step S105).

That is, in the reforming process in step S105, the control device opens the conveyance valve 133D of the water supply path 133 and the circulation valve 191A of the circulation path 191 and drives the conveyance pump 133C of the water supply path 133 of the vaporizing means 130. The pure water 133A stored in the pure water tank 133B is supplied to the heat exchange device 132. By supplying the pure water 133A, steam is generated by heat exchange with the exhaust gas from the reformer 141 in the heat exchange device 132 and supplied to the vaporizer 131. By supplying the water vapor to the vaporizer 131, the water vapor is supplied to the reforming unit 140, and the inert gas or the like charged in the reforming unit 140 before the start-up flows into the storage unit 192 of the circulation path 191. In this state, the fuel gas valve 163A is controlled to be opened, and the switching valve 165A and the opening / closing valve 146A are controlled to be closed.
By the inflow of the inert gas, the inert gas is stored in the storage means 192, and the mixed water vapor is recovered as water (pure water 133A) by heat radiation.
The control device then supplies the water vapor and closes the circulation valve 191A after a predetermined time, for example, a time during which almost all of the inert gas flows into the circulation path 191, and closes the fuel gas supply path 146. The on-off valve 146A is opened, and the supply steam is switched to a state where the supplied water vapor is supplied to the burner 141A.
Further, the control device opens the desulfurization fuel valve 122A of the desulfurization fuel path 122 of the desulfurization means 120, drives a desulfurization fuel pump (not shown), and stores the desulfurized liquid fuel 111A stored in the buffer tank of the desulfurization means 120. Is supplied to the vaporizer 131 of the vaporization means 130. By supplying the liquid fuel 111A to the vaporizer 131, it is mixed with water vapor supplied from the heat exchange device 132 to the vaporizer 131, vaporized, and supplied as vaporized liquid fuel to the reformer 141 of the reforming means 140.
Further, the control device opens the fuel supply valve 112B of the liquid fuel supply path 112 and drives the liquid fuel pump 112A to supply the liquid fuel 111A stored in the liquid fuel storage tank 111 to the desulfurizer 121 of the desulfurization means 120. The fuel is supplied through the fuel supply pipe 112C. By supplying the liquid fuel 111A to the desulfurizer 121, the liquid fuel 111A adsorbs and removes sulfur compounds contained by contact with the desulfurizing agent and flows into the buffer tank.
Further, the control device closes the fuel gas valve 163A, opens the switching valve 165A of the bypass path 165, supplies the gas that is supplied from the vaporizer 131 as vaporized liquid fuel, reformed by the reforming means 140, and flows out. The fuel is supplied to the burner 141A of the reformer 141 through the bypass path 165 and the fuel gas supply path 146. That is, the fuel gas processed in the unstable reforming state of the vaporized liquid fuel in the reforming means 140 is used for combustion for stable heating of the reformer 141.

After the reforming process in step S105, the control device confirms conditions such as the temperatures of the reformer 141, the CO converter 142, and the CO selective oxidizer 143 for the reforming process in the reforming means 140 ( Step S106). If it is recognized in step S106 that the conditions for the reforming process are satisfied, the oxidation blower 143A is driven to supply air to the CO selective oxidizer 143. By supplying this air, the CO that is not transformed by the CO transformer 142 is oxidized to carbon dioxide (CO ₂ ), and the CO in the fuel gas is removed.
Then, after checking the reforming process conditions in step S106, it is determined whether or not the reforming unit 140 has stabilized, for example, whether or not a stable time has elapsed. When the control device recognizes that the stabilization time of the reforming means 140 has elapsed (step S107), the control device performs a power generation process (OCV process) (step S108).

That is, the control device opens the air valve 153 of the oxygen-containing gas supply unit 150 and drives the blower 151 to supply air to the second humidifying unit 162 of the humidifier 160. Further, the second humidifier 162 of the humidifier 160 humidifies with pure water 133A supplied from the pure water tank 133B while heating the air to 60 to 70 ° C., for example. Then, the air humidified by the second humidifying unit 162 is supplied to the positive electrode 171 of the fuel cell 170.
Further, the control device closes the switching valve 165A of the bypass path 165, opens the fuel gas valve 163A of the fuel gas supply path 163, and supplies the hydrogen-rich fuel gas reformed by the reforming means 140. It is made to supply to the 1st humidification part 161 of the humidifier 160. FIG. Further, the first humidifier 161 of the humidifier 160 humidifies the fuel gas with pure water 133A supplied from the pure water tank 133B while adjusting the fuel gas to 60 to 70 ° C., for example. Then, the fuel gas humidified by the first humidifying unit 161 is supplied to the negative electrode 172 of the fuel cell 170.
By supplying humidified air and fuel gas from the humidifier 160, the fuel cell 170 reacts with hydrogen in the supplied fuel gas and oxygen in the supplied air to generate water (pure water 133A). At the same time, DC power is generated between the positive electrode 171 and the negative electrode 172. Then, the control device checks the voltage of the DC power generated in the fuel cell 170 (step S109), converts the generated DC power into AC power via an inverter (not shown) of the control device, and supplies it to the power load ( Step S110). Specifically, the state is switched from a state in which commercial AC power is supplied from the outside to a state in which the fuel cell system 100 is supplied as household power.
In this manner, by recognizing that power is generated at a predetermined voltage (step S111), the routine proceeds to steady operation processing (step S112). That is, to control the flow rate of the liquid fuel 111A, to control the electric power supplied to the electric heater that is the heating condition of the desulfurization heating means of the desulfurizer 121, to control the combustion of the burner 141A of the reformer 141, and to generate water vapor in the heat exchange device 132 The operation state of the entire fuel cell system 100 is controlled, such as the supply amount control of the pure water 133A, temperature management, and power generation amount management.

(Stop processing)
Next, as an operation in the fuel cell system 100, a stop process that is an operation at the time of stop will be described with reference to FIG.
FIG. 3 is a flowchart showing the control operation of the stop process.

First, when the control device acquires a signal related to a stop request, the control device performs a stop process (step S201). Signals related to this stop request include input operations such as switch switching operations by the user, timer control for recognizing that the time measuring means for measuring the current time has reached a preset time, and a reduction in power consumption at the power load Or the signal accompanying a fall, the signal accompanying the fall of the electrical storage amount of a storage battery, etc. can be illustrated.
That is, the control device cuts off the supply to the power load generated by the fuel cell 170 and switches to a state in which, for example, commercial AC power is supplied. Further, an inverter (not shown) of the control device is turned off. Then, the control device closes the fuel gas valve 163A of the fuel gas supply path 163 and stops the humidifier 160, and the fuel via the humidifier 160 of the hydrogen-rich fuel gas reformed by the reforming means 140 Supply to the battery 170 is stopped. Further, the control device closes the desulfurization fuel valve 122A of the desulfurization fuel path 122 of the desulfurization means 120, stops driving of a desulfurization fuel pump (not shown), and stores the desulfurized liquid stored in the buffer tank of the desulfurization means 120. The supply of the fuel 111A to the vaporizer 131 is shut off. Further, the control device closes the fuel supply valve 112B of the liquid fuel supply path 112 and stops driving the liquid fuel pump 112A, and supplies the liquid fuel 111A stored in the liquid fuel storage tank 111 to the desulfurizer 121. To stop.

After the stop process in step S201, the control device performs a first purge process (step S202).
That is, the control device opens the inert gas valve 182A, the first valve 182C1, the second valve 182D1, and the third valve 182E1 of the inert gas supply path 182, and desulfurizes the inert gas stored in the inert gas tank 181. While supplying to the downstream side of the means 120, the switching valve 165A of the bypass path 165 is opened.
Specifically, the inert gas is supplied to the desulfurization fuel valve 122A and the vaporizer 131 in the desulfurization fuel path 122 via the inert gas supply pipe 182B and the first supply pipe 182C. By supplying the inert gas, the inert gas mixed with the water vapor in the vaporizer 131 flows into the reforming unit 140, and the reformed gas such as vaporized liquid fuel or fuel gas remaining in the reforming unit 140 is bypassed. Through 165, the gas flows so as to be pushed out to the burner 141A, and the inert gas sequentially flows into the reformer 141, the CO converter 142, and the CO selective oxidizer 143 to be replaced.
In addition, the inert gas is supplied between the fuel gas valve 163A and the first humidifier 161 of the humidifier 160 in the fuel gas supply path 163 via the inert gas supply pipe 182B and the second supply pipe 182D. By this supply, the fuel gas remaining in the first humidification unit 161 and the negative electrode 172 of the fuel cell 170 flows through the fuel gas supply path 146 so as to be pushed out to the burner 141A, and the inert gas flows through the first humidification unit 161. Then, the fuel cell 170 sequentially flows into the negative electrode 172 to be replaced.
Further, the inert gas is supplied to the downstream side of the transport pump 144A in the fuel transport path 144 via the first supply pipe 182C and the third supply pipe 182E. The supply of the inert gas causes the liquid fuel 111A remaining on the downstream side of the transport pump 144A in the fuel transport path 144 to be pushed out and burned to the burner 141A, and the inert gas is transported to the transport pump 144A in the fuel transport path 144. More downstream side and burner 141A are sequentially introduced and replaced. This can prevent the liquid fuel 111A remaining due to the residual heat from being solidified or seized.

Then, the control device determines whether or not the first purge of the inert gas is completed, for example, whether or not a predetermined time has elapsed since the start of the supply of the inert gas. When the control device recognizes that the predetermined time has elapsed (step S203), that is, that the reformed gas or fuel gas has been removed from the vaporizer 131 to the negative electrode 172 of the fuel cell 170, the supply of the inert gas is interrupted. To do. That is, the control device closes the inert gas valve 182A, the first valve 182C1, the second valve 182D1, and the third valve 182E1 of the inert gas supply path 182.
In this state, the reformer 141 is still at a relatively high temperature, so that steam is generated by the heat exchange device 132, supplied to the vaporizer 131, and flows into the reforming means 140. That is, the inert gas purged in the first purge step flows to the burner 141A via the bypass path 165 so that it is pushed out by the steam, and the negative electrode 172 of the fuel cell 170 is purged from the reforming means 140 by the steam. It becomes a state. In this state, the fuel gas valve 163A is controlled to be opened.
The inflow of the steam into the reforming unit 140 accelerates the cooling of the reforming unit 140, particularly the reformer 141. In this water vapor purge, the inert gas may not be allowed to flow through the burner 141A, but may flow into the circulation means 190 and be collected by the storage means 192.
Then, the control device determines whether or not the water vapor purge has been performed for a predetermined time length, and recognizes that the water vapor purge has been performed for a predetermined time length (step S204), transports the water supply path 133 of the vaporizing means 130. The valve 133D is closed and the drive of the transport pump 133C is stopped, and the supply of the pure water 133A to the heat exchange device 132 is stopped. By stopping the supply of the pure water 133A, the generation of water vapor is stopped and the water vapor purge is stopped.

Thereafter, the control device performs a second purge of the inert gas.
That is, the control device opens the inert gas valve 182A and the first valve 182C1 of the inert gas supply path 182. Further, the control device closes the opening / closing valve 146A of the fuel gas supply path 146, opens the circulation valve 191A of the circulation means 190, and drives the circulation blower 193 of the circulation means 190. As a result, the inert gas is supplied to the desulfurized fuel valve 122A and the vaporizer 131 in the desulfurized fuel path 122 via the inert gas supply pipe 182B and the first supply pipe 182C. Due to the supply of the inert gas, the water vapor purged from the vaporizer 131 to the negative electrode 172 of the fuel cell 170 flows into the storage means 192 through the circulation path 191 so as to be pushed out. The water vapor flowing into the storage means 192 is cooled and deposited as water (pure water 133A) and is retained in the storage means 192. Note that the inert gas that sufficiently pushes out the water vapor and flows out from the negative electrode 172 of the fuel cell 170 also flows into the storage unit 192 through the circulation path 191, and the water vapor or water (pure water 133A) is vented to the gas-liquid separation unit 192A. After being removed by the trap, it is returned to the inert gas supply position by the circulation blower 193 and circulated.
Then, the control device determines whether or not the second purge of the inert gas is completed, for example, whether or not a predetermined time has elapsed since the start of the supply of the inert gas. When the control device recognizes that the predetermined time has elapsed (step S205), that is, the inert gas is returned to the first supply pipe 182C and circulates, the inert gas valve of the inert gas supply path 182 is recognized. The supply of 182A is stopped, and only the already supplied inert gas is circulated.
Thereafter, when the control device recognizes that the predetermined time has elapsed, that is, the reforming means 140 has cooled to a temperature below which the water vapor is cooled and water is deposited, the inert gas is sealed. Specifically, the control device closes the first valve 182C1, the circulation valve 191A, the fuel gas valve 163A of the fuel gas supply path 163, and the switching valve 165A, and stops the operation of the circulation blower 193 to deactivate the inert gas. The circulation from the vaporizer 131 to the negative electrode 172 of the fuel cell 170 is purged with an inert gas. Further, the control device closes the air valve 153 of the oxygen-containing gas supply means 150 and stops the driving of the blower 151, so that the air from the second humidification unit of the humidifier 160 to the positive electrode 171 of the fuel cell 170 is stopped. Stop supplying. Further, the control device closes the air supply valve 145B of the air supply path 145 and stops the driving of the air supply blower 145A, stops the supply of combustion air to the burner 141A, and the fuel cell system 100 Suspended.

[Effects of fuel cell system]
As described above, in the fuel cell system 100 of the above embodiment, the liquid fuel 111A is desulfurized by the desulfurization means 120 and vaporized by the vaporization means 130, and then reformed by the reforming means 140, and the oxygen-containing gas supply means 150 is obtained. In the system configuration in which the fuel cell 170 reacts with the air supplied by the fuel cell 170 to generate power, the supply of the liquid fuel 111A desulfurized by the desulfurization means 120 to the vaporization means 130 is stopped and the operation is stopped when the operation is stopped. In this way, the inert gas is supplied downstream from the desulfurization means 120, and the effluent flowing out from the fuel cell 170 is supplied downstream from the desulfurization means 120 by the circulation means 190 connected to the fuel cell 170. I am letting.
For this reason, even when the liquid fuel that is the raw material of the fuel cell is purged with the liquid fuel and the reforming catalyst is coated and the liquid fuel that cannot perform the catalytic function is used as the raw material, the inert gas is supplied and the inert gas is the fuel. The inert gas is circulated by being supplied downstream from the desulfurization means 120 by the circulation means 190 in the state of being discharged as the effluent from the battery 170, and it is not necessary to supply the inert gas newly. It is only necessary to supply the gas at a minimum, and the inert gas can be reused with a simple configuration that returns the inert gas to be supplied. Driving can be provided.
Furthermore, since the amount of inert gas used for purging can be reduced, for example, the frequency of filling an inert gas tank filled with an inert gas can be reduced, and maintenance management is facilitated. For this reason, for example, the frequency of replacement of the inert gas tank is reduced due to a decrease in the filling frequency of the inert gas, and a small inert gas tank can be used, so that a small system configuration that can be installed for home use can be easily constructed.

A storage unit 192 for storing the effluent is provided in the circulation unit 190 that is connected to the fuel cell 170 and supplies the effluent flowing out from the fuel cell 170 to the downstream side of the desulfurization unit 120.
For this reason, even when the inert gas is supplied in a somewhat excessive amount for purging with the inert gas, the excess is recovered by the storage means 192, or the inert gas remaining at the time of restart is circulated to the circulation means 190 for storage. Further effective utilization of the inert gas such as recovery by means 192 can be easily obtained, and more efficient operation control can be obtained.

In addition, gas-liquid separation means 192A for gas-liquid separation of the effluent flowing out from the fuel cell 170 by purging with an inert gas is provided in the circulation means 190, and the separated gas is supplied downstream from the desulfurization means 120.
For this reason, when the inert gas is supplied and purged, water generated by the humidifier 160 that flows out as effluent, water that is a reaction product in the fuel cell 170, vaporization of the liquid fuel 111A, and steam reforming are performed. For example, water derived from water vapor to be mixed is separated and removed, and it is easy to circulate a dry inert gas with a simple configuration, and the reforming ability of the reforming means 140 is reduced by returning water. That is, the catalyst function can be prevented from being lowered and a good stop state can be easily obtained.

Further, as the vaporization means 130, steam is generated by the heat exchange device 132 by exhaust from the reforming means 140, and the vapor is mixed and vaporized by the vaporizer 131 with the liquid fuel 111A desulfurized by the desulfurization means 120, The liquid phase fraction collected by the gas-liquid separation of the effluent by the gas-liquid separation means 192A of the circulation means 190, that is, water as a raw material of the water vapor is supplied to the heat exchanging device 132 to generate water vapor that vaporizes the liquid fuel 111A.
For this reason, water (pure water 133A), which is a raw material of water vapor for efficiently generating hydrogen gas that is mixed with the liquid fuel 111A and generated by the fuel cell 170, can be recovered well, and a good water balance can be obtained. The supply of pure water 133A can be reduced or stopped, and more efficient operation can be obtained.

Further, the inert gas supply means 180 performs the first purge step of supplying the inert gas for a predetermined time after the supply of the liquid fuel 111A desulfurized by the desulfurization means 120 is stopped, and then the inert gas is supplied after the predetermined time has elapsed. A second purge step for resupply is performed.
For this reason, after the supply of the liquid fuel 111A is stopped, the inactive gas purge causes inconvenience such as carbonization, scorching, and blockage due to the liquid fuel 111A and the reformed gas derived from the liquid fuel 111A remaining in the reforming means 140 and the like. In this case, the supply of the inert gas is temporarily interrupted, and for example, the steam supplied from the vaporization means 130 for reforming the liquid fuel 111A is supplied to the reforming means 140, thereby quickly cooling the reforming means 140. The inert gas is re-supplied after the elapse of a predetermined time, such as before the reforming means 140 is cooled to some extent and the water vapor is precipitated as water, and the water is deposited and modified as described above due to the residual water vapor. Inconveniences such as deterioration of quality characteristics can be prevented, and operation can be stopped quickly and efficiently.

The inert gas supply means 180 supplies an inert gas upstream from the vaporization means 130 and downstream from the desulfurization means 120.
For this reason, for example, in the portion upstream of the vaporization means 130 in which the liquid fuel 111A flows in the desulfurized fuel path 122 in the liquid phase, the liquid fuel 111A remains when the supply of the liquid fuel 111A is shut down to stop the operation. This can prevent the inconvenience such as carbonization of the remaining liquid fuel 111A due to the residual heat of the reforming means 140.

Further, the inert gas supply means 180 supplies an inert gas downstream from the desulfurization means 120, and the downstream side of the reforming means 140 is upstream of the fuel cell 170, that is, the fuel gas valve 163A in the fuel gas supply path 163. It is supplied further upstream than the humidifier 160 on the downstream side.
For this reason, the region of the humidifier 160 and the fuel cell 170 on the downstream side of the reforming means 140 that does not cause any inconvenience even if water derived from water vapor is deposited, and the reforming that causes inconvenience such as deterioration in reforming characteristics due to water remaining. A configuration in which an inert gas is supplied independently from the region on the mass means 140 side is obtained. Therefore, the amount of the inert gas used is supplied by supplying steam to the region on the reforming means 140 side for rapid cooling in the reforming means 140 and re-supplying the inert gas for discharging the steam. Can be further reduced, and more efficient operation can be obtained.

The burner 141A that is heated to reform the liquid fuel 111A vaporized by the vaporization means 130 in the reforming means 140 is connected to the fuel cell 170 and supplied with the effluent flowing out from the fuel cell 170 to burn the fuel. A circulation unit 190 is connected to the gas supply path 146 to supply the inert gas supplied in the second purge step, which is an effluent, to the downstream side of the desulfurization unit 120.
For this reason, the supply of the liquid fuel 111A is stopped and hydrogen gas or carbon monoxide, which is an effluent flowing out of the fuel cell 170 by purging with the inert gas, is burned by the burner 141A to improve energy efficiency and carbon monoxide. In this way, it is possible to prevent environmental destruction due to the exhaust of the gas, and to supply water vapor to the reforming means 140 for quick cooling, and then to circulate the water vapor and the inert gas content flowing out from the fuel cell 170 by purging with the inert gas. The gas-liquid separation unit 192A separates and removes the water vapor, and only the dry inert gas is supplied and circulated, so that a good and efficient operation can be performed from the fuel gas supply path 146 through the circulation unit. It can be easily obtained with a simple configuration in which 190 is branched.

Further, an inert gas is also supplied to a fuel transfer path 144 that supplies liquid fuel burned by the burner 141A for heating in the reforming means 140 to the burner 141A.
Thus, when the operation is stopped, the supply of the liquid fuel 111A is stopped and the heating by the burner 141A is stopped, so that the liquid fuel 111A remaining in the fuel transfer path 144 for supplying the liquid fuel 111A to the burner 141A is an inert gas. Therefore, inconveniences such as carbonization of the remaining liquid fuel 111A due to residual heat of the reforming means 140 can be prevented, and a stable and good operation can be obtained.

Then, nitrogen gas that is widely used is used for purging.
For this reason, even if it constructs | assembles as a home system, for example, supply of nitrogen gas can be performed easily and expansion of utilization is obtained easily.

In addition, overall control is performed by the control device.
For this reason, temperature, flow rate, valve opening / closing timing, pump drive stop timing, etc. can be controlled relatively easily.For example, it is easy to construct inert gas purge and circulation control by software program control etc. Automatic control can be easily performed as a home system in which stop and start are performed relatively frequently.
Note that the control device is not limited to a single form such as a plurality of circuit boards, and various forms such as a structure in which a plurality of control circuits are constructed as a network can be applied.

[Modification of Embodiment]
The aspect described above shows one aspect of the present invention, and the present invention is not limited to the above-described embodiment, and within the scope of achieving the objects and effects of the present invention. Needless to say, the modifications and improvements are included in the contents of the present invention. In addition, the specific structure and shape in carrying out the present invention may be used as other structures and shapes within the scope of achieving the object and effect of the present invention.

That is, the fuel cell system of the present invention is not limited to a configuration in which the operation is controlled by the control device, but may be configured to be controlled for each configuration of the desulfurization means 120, the vaporization means 130, the reforming means 140, and the like.
In addition, as a control configuration, any configuration can be configured, such as a configuration in which valve opening / closing and pump or blower drive control are performed by software signal control as a general control, or a configuration in which control is performed by hardware of each configuration. Applicable.

And although it was set as the structure which heats and desulfurizes the liquid fuel 111A, the structure which desulfurizes at normal temperature, for example, without heating can also be applied. In such a configuration, a buffer tank or the like can be omitted, and energy consumption for heating can be prevented.
Further, vaporization of the liquid fuel 111A is not limited to steam mixing, for example, by directly vaporizing by heat exchange with the exhaust gas from the reforming means 140 and separately mixing steam, using an ejector, etc. A vaporizer can be used.
Furthermore, the reformer 141, the CO converter 142, and the CO selective oxidizer 143 have been described as the reforming means 140. However, any configuration that generates hydrogen-rich gas from liquid fuel can be applied.
Further, the fuel cell 170 is not limited to the solid polymer type, and other various configurations can be applied.

Although the second supply pipe 182D is provided and described, only the first supply pipe 182C is provided, and the inert gas may not be supplied between the reforming unit 140 and the humidifier 160.
With this configuration, the system configuration can be further simplified, the control can be easily performed, the system construction can be further improved, and the size can be further reduced.
In such a configuration, the bypass path 165 may not be provided.

Further, although the storage unit 192 is provided as the circulation unit 190, for example, the storage unit 192 may not be provided, and only the gas-liquid separation unit 192A such as the separator 175 that is a separator may be provided.
Furthermore, the gas-liquid separation means 192A is not provided, and, for example, as a configuration that dissipates heat without insulating the piping of the circulation path 191, when circulating, the water vapor is cooled to become water and separated by the drain provided in the piping. Etc.

As the inert gas purge, for example, the first purge process may not be performed, and only the water vapor may be supplied and then the second purge process, which is the supply of the inert gas of the present invention, may be performed.
In this case, the remaining liquid fuel 111A is disposed upstream of the vaporization means 130 so that the residual heat from the reforming means 140 is not transmitted or the staying liquid fuel 111A is returned to the liquid fuel storage tank 111. It is preferable that inconvenience such as carbonization does not occur.

Furthermore, although the configuration of purging from the reforming means 140 to the negative electrode 172 of the fuel cell 170 at the time of stoppage is illustrated, the following configuration may be used.
For example, only the reforming means 140 is purged when stopped. Here, when purging only the reforming means 140, only the reformer 141 may be purged, or the CO converter 142 and the CO selective oxidizer 143 may be purged. In the reforming step, the fuel gas valve 163A and the opening / closing valve 146A are closed, and the switching valve 165A is opened, so that water vapor, liquid removal gas filled in the reforming means 140, etc. Without being supplied to the negative electrode 172, only the burner 141A is supplied and burned. Thereafter, the combustion gas valve 163A and the opening / closing valve 146A may be opened after a predetermined time, for example, a time for which all the liquid removal gas is burned. In addition to burning, for example, the reforming unit 140 may store the gas separately until it reaches a predetermined temperature and can remove CO, or may circulate the gas.
If only the reforming means 140 is purged, even if the liquid removal gas or the like charged in the reforming means 140 before starting contains CO, this CO is the fuel. Since it is burned by the burner 141A without being supplied to the negative electrode 172 of the battery 170, deterioration of the negative electrode 172 can be prevented.

  Moreover, you may distribute | circulate independently as a control program of a control apparatus.

  In addition, the specific structure and shape in the implementation of the present invention may be other structures as long as the object of the present invention can be achieved.

  The present invention can be used for purging by supplying an inert gas in a fuel cell system that generates power using liquid fuel such as kerosene as a raw material.

1 is a block diagram showing a schematic configuration of a fuel cell system according to an embodiment of the present invention. It is a flowchart which shows the operation | movement of the starting process in the said embodiment. It is a flowchart which shows the operation | movement of the stop process in the said embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Fuel cell system 111A ... Liquid fuel 120 ... Desulfurization means 122 ... Desulfurization fuel path 130 ... Vaporization means 131 ... Vaporizer 132 ... Heat exchange apparatus 140 ... Reformation means 141A ... Burner 146 ... Return Fuel gas supply path 150... Oxygen-containing gas supply means 170... Fuel cell 180... Inert gas supply means 190 .. Circulation means 192... Storage means 192 A.

Claims (13)

Desulfurization means for desulfurizing liquid fuel;
A vaporization means for vaporizing the liquid fuel desulfurized by the desulfurization means into a raw material gas;
Reforming means for reforming the source gas into fuel gas;
An oxygen-containing gas supply means for supplying an oxygen-containing gas;
A fuel cell that generates power using the fuel gas reformed by the reforming means and the oxygen-containing gas supplied by the oxygen-containing gas supply means;
An inert gas supply means for supplying an inert gas downstream from the desulfurization means when the operation of the liquid fuel desulfurized by the desulfurization means is stopped by stopping supply to the vaporization means;
A circulation unit connected to the fuel cell and supplying the effluent flowing out from the fuel cell to the downstream side of the desulfurization unit when the inert gas is supplied by the inert gas supply unit;
A fuel cell system comprising: The fuel cell system according to claim 1,
The fuel cell system according to claim 1, wherein the circulation unit includes a storage unit that is connected to the fuel cell and stores effluent that flows out of the fuel cell. The fuel cell system according to claim 1 or 2, wherein
The fuel cell system, wherein the circulation means includes gas-liquid separation means for gas-liquid separation of the effluent, and supplies the separated gas downstream from the desulfurization means. The fuel cell system according to claim 3,
The vaporization means mixes the water vapor generated by the exhaust from the reforming means with the liquid fuel desulfurized by the desulfurization means by mixing the water vapor generated by the heat exchange apparatus and vaporizes the raw material gas. With a vaporizer to let
The fuel cell system, wherein the gas-liquid separation unit supplies the liquid phase component collected by gas-liquid separation of the effluent to the heat exchange device to generate the water vapor. The fuel cell system according to claim 4, wherein
The inert gas supply means supplies the inert gas for a predetermined time length when the supply of the liquid fuel desulfurized by the desulfurization means to the vaporization means is stopped, and a predetermined time length of the inert gas. A fuel cell system, wherein the inert gas is resupplied when the supply of water vapor from the heat exchange device to the vaporizer in the vaporizer is stopped after a lapse of a predetermined time after the supply. A fuel cell system according to any one of claims 1 to 5,
The fuel cell system, wherein the inert gas supply means supplies the inert gas upstream from the vaporization means and downstream from the desulfurization means. A fuel cell system according to any one of claims 1 to 6,
The inert gas supply means supplies the inert gas downstream from the desulfurization means and also supplies the inert gas downstream from the reforming means and upstream from the fuel cell. A fuel cell system according to any one of claims 1 to 7,
The reforming means includes a burner that heats to reform the source gas vaporized by the vaporization means,
A return means connected to the fuel cell and supplying the burner flowing out from the fuel cell to the burner for combustion;
The said circulation means is connected to the said fuel cell via the said return means. The fuel cell system characterized by the above-mentioned. The fuel cell system according to claim 8, wherein
The burner burns and heats the liquid fuel,
The said inert gas supply means supplies the said inert gas also to the path | route which supplies the said liquid fuel to the said burner. The fuel cell system characterized by the above-mentioned. This is an operation control method for a fuel cell system that controls the operating state of a fuel cell system in which liquid fuel is desulfurized by a desulfurization means and then vaporized as a raw material gas by a vaporization means and then reformed by a reforming means and then supplied to the fuel cell to generate power. And
A desulfurization fuel path provided with a desulfurization fuel valve for supplying the liquid fuel from the desulfurization means to the vaporization means, an inert gas supply means for supplying an inert gas downstream from the desulfurization means, and the fuel cell. Using circulation means for supplying the effluent flowing out from the fuel cell to the downstream side of the desulfurization means,
A fuel supply shut-off step of switching the desulfurization fuel valve to shut off the supply of the liquid fuel from the desulfurization means to the vaporization means;
An inert gas purge step of supplying the inert gas downstream from the desulfurization means from the inert gas supply means after shutting off the supply of the liquid fuel in the fuel supply cutoff process;
A circulation step of supplying the inert gas in the inert gas purging step to supply the effluent flowing out of the fuel cell through the circulation means to the downstream side of the desulfurization means. A fuel cell system operation control method. An operation control method for a fuel cell system according to claim 10,
In the circulation step, the effluent flowing out from the fuel cell is subjected to gas-liquid separation, and the gas phase component is supplied downstream from the desulfurization means. An operation control method for a fuel cell system according to claim 10 or 11,
The inert gas purge step includes:
A first purge step of supplying the inert gas from the inert gas supply means to the downstream side of the desulfurization means for a predetermined time after shutting off the supply of the liquid fuel;
A second purge step of supplying the inert gas from the inert gas supply means downstream of the desulfurization means after a predetermined time has elapsed after supplying the inert gas for a predetermined time in the first purge step; An operation control method for a fuel cell system. An operation control method for a fuel cell system according to claim 12,
In the circulation step, the effluent flowing out from the fuel cell in the second purge step is supplied downstream from the desulfurization means.

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