JP2007311359A - Fuel cell power generation system and its operation method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell generation system in which a purge process of an atmosphere in a fuel gas passage can be realized without using nitrogen after power generation is over. <P>SOLUTION: The fuel cell power generation system is provided with a fuel cell, a fuel gas supplying means which includes a fuel gas generation means by which a hydrogen-rich fuel gas is generated from a raw material mainly composed of a compound containing carbon and hydrogen and supplies the fuel gas for the fuel cell to a fuel gas passage, an oxidant gas supplying means to supply oxidant gas to an oxidant gas passage of the fuel cell, a substitute gas supplying means to supply the raw material as a substitute gas to the fuel gas passage and a steam supplying means to supply steam to the fuel gas generating means. After power generation in the fuel cell is over, an atmosphere in the fuel gas passage is substituted with the raw material by pouring the raw material through the substitute gas supplying means, and when fuel gas generation of the fuel gas generating means is stopped, steam is poured into the fuel gas generating means through the steam supplying means and the atmosphere in the fuel gas generating means is substituted by steam. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a fuel cell power generation system that generates power using a fuel cell and an operation method thereof.

  A conventional fuel cell power generation system or power generation method has a configuration as shown in FIG. 20 as disclosed in Japanese Patent Laid-Open No. 3-257762. That is, a fuel cell 1, a desulfurizer 3 that removes a sulfur component from a source gas such as natural gas, a reaction unit 2a of a fuel gas generation unit 2 that generates a hydrogen-rich gas from the desulfurized source gas, and a reaction unit 2a Burner 2b as a heating means for heating the fuel, and a nitrogen facility 5 connected by a nitrogen supply pipe 7 having a shut-off valve 6 upstream of the fuel gas generator 2, and the fuel generated in the fuel gas generator 2 is The fuel is supplied to the fuel electrode 1a of the fuel cell 1 through the reformed gas supply pipe 8, and the remaining fuel is supplied to the burner 2b through the exhaust hydrogen connection pipe 9. Air is supplied to the oxidant electrode of the fuel cell 1 by the blower 4.

  In a general fuel cell power generation system or power generation method, when the power generation operation is stopped, the supply of the raw material gas is first stopped. The phenomenon that occurs at this time will be described with reference to FIG. 20. In the flow path from the fuel gas generator 2 to the reformed gas supply pipe 8 and the fuel cell 1 to the exhaust hydrogen connection pipe 9, in particular, drainage from the fuel electrode 1a. The hydrogen rich gas stops in the flow path extending to the elementary connection pipe 9. Therefore, when air flows into the hydrogen rich gas flow path from the burner 2b released to the atmosphere by natural convection, there is a risk that hydrogen will explode.

Therefore, in the fuel cell power generation system or power generation method described in the above-mentioned Japanese Patent Application Laid-Open No. 3-257762 and shown in FIG. 20, the shutoff valve 6 is opened when the power generation operation is stopped, and the nitrogen facility 5 is not connected via the nitrogen supply pipe 7. Nitrogen gas as an active gas passes from the fuel gas generating section 2 to the exhaust hydrogen connection pipe 9 through the reformed gas supply pipe 8 and the fuel cell 1, particularly from the fuel electrode 1 a to the exhaust hydrogen connection pipe 9. The hydrogen rich gas was discharged from the fuel gas flow channel with nitrogen gas, that is, purged, and the purged hydrogen rich gas was burned by the burner 2b. As described above, in the conventional fuel cell power generation system, hydrogen is prevented from exploding by the purge process from the fuel gas flow path of the hydrogen rich gas by the nitrogen gas, and safety is ensured.
JP-A-3-257762

  In the conventional fuel cell power generation system or power generation method, it is necessary to provide nitrogen equipment such as a nitrogen cylinder for the above-described purging process with nitrogen gas. For example, when used for a home-use stationary distributed power generation or a power source for an electric vehicle There is a problem that a large space is required and the initial cost is high. In addition, it is necessary to periodically replace and replenish the nitrogen cylinder, and there is a problem that the running cost is high.

  Further, when the fuel gas generator is started, the generated fuel gas contains a high concentration of carbon monoxide. If the fuel cell is a solid polymer electrolyte fuel cell, this poisons the fuel electrode catalyst of the fuel cell. However, in the conventional fuel cell power generation system or power generation method, fuel gas containing a high concentration of carbon monoxide at the time of start-up is supplied to the fuel cell, causing performance deterioration due to catalyst poisoning of the fuel electrode of the fuel cell. .

  In consideration of the problems of the conventional fuel cell power generation system or power generation method as described above, the present invention purges the hydrogen rich gas from the fuel gas flow path without using nitrogen before the start of power generation and after the end of power generation. An object of the present invention is to provide a fuel cell power generation system and a power generation method that can be performed. It is another object of the present invention to provide a fuel cell power generation system and a power generation method capable of preventing inflow of high concentration carbon monoxide into the fuel cell at the start of system operation.

The fuel cell power generation system of the present invention includes a fuel cell having a fuel electrode and an oxidant electrode, and a fuel gas generation means for generating a hydrogen-rich fuel gas from a raw material mainly composed of a compound containing carbon and hydrogen, A fuel gas supply means for supplying the fuel gas to the fuel gas flow path of the fuel cell including the fuel electrode; and an oxidant gas for supplying an oxidant gas to the oxidant gas flow path of the fuel cell including the oxidant electrode. A supply means, a replacement gas supply means for supplying the raw material as a replacement gas to the fuel gas flow path, and a water vapor supply means for supplying water vapor to the fuel gas generation means,
After the power generation of the fuel cell, the replacement gas supply means injects the raw material into the fuel gas flow path to replace the atmosphere of the fuel gas flow path with the raw material, and the fuel gas generation means generates fuel gas. And the steam is injected into the fuel gas generation means by the water vapor supply means to replace the atmosphere inside the fuel gas generation means with the water vapor.

Air supply means for supplying air to the fuel gas flow path to replace the atmosphere of the fuel gas flow path with air, and after completion of power generation, the replacement gas supply means supplies the raw material to the fuel gas flow path. After injecting and replacing the atmosphere of the fuel gas flow path with the raw material, the air is injected into the fuel gas flow path by the air supply means to replace the atmosphere of the fuel gas flow path with the air. It is preferable to configure.
It is preferable that the fuel gas generation unit performs fuel gas generation until the injection of the raw material into the fuel gas flow path by the replacement gas supply unit is completed.
After completion of power generation, the replacement gas supply means injects the raw material into the fuel gas flow path, replaces the atmosphere of the fuel gas flow path with the raw material, and then stops the fuel gas generation of the fuel gas generation means. Preferably, the steam is injected into the fuel gas generating means by the steam supply means, and the atmosphere inside the fuel gas generating means is replaced with the steam.
After the power generation is completed, the fuel gas generation unit stops the fuel gas generation, and the water vapor supply unit injects the water vapor into the fuel gas generation unit to replace the atmosphere inside the fuel gas generation unit with the water vapor. In addition, it is preferable that the raw material is injected into the fuel gas flow path by the replacement gas supply means to replace the atmosphere of the fuel gas flow path with the raw material.

Air supply means for supplying air to the fuel gas flow path and the fuel gas generation means to replace the atmosphere of the fuel gas flow path and the atmosphere inside the fuel gas generation means with the air; Injecting the raw material into the fuel gas flow path to replace the atmosphere of the fuel gas flow path with the raw material, and injecting the water vapor into the fuel gas generation means to change the atmosphere inside the fuel gas generation means to the After substituting with water vapor, the air is injected into both the fuel gas flow path and the fuel gas generation means by the air supply means, and the atmosphere of the fuel gas flow path and the atmosphere inside the fuel gas generation means Are preferably replaced with the air.
The air injection by the air supply means is preferably performed in series from the fuel gas generation means to the fuel gas flow path.
The air injection by the air supply means is preferably performed in parallel with the fuel gas generation means and the fuel gas flow path.
Hydrogen gas for supplying a hydrogen gas containing at least carbon monoxide and water vapor as subcomponents to the shift portion, wherein the fuel gas generating means is provided with a shift catalyst body having at least a noble metal and a metal oxide as constituent materials. It is preferable to comprise a supply part.

The replacement gas supply means comprises bypass means for bypassing the fuel gas generation means and injecting the raw material into the fuel gas flow path, and after completion of power generation of the fuel cell, the bypass gas supply means passes through the bypass means. It is preferable that the raw material is injected into the fuel gas channel and the atmosphere of the fuel gas channel is replaced with the raw material.
Air supply means for supplying air to the fuel gas flow path and replacing the atmosphere of the fuel gas flow path with the air is further provided, and after the power generation is completed, the raw material is injected into the fuel gas flow path by the bypass means. Then, after replacing the atmosphere of the fuel gas flow path with the raw material, the air is injected into the fuel gas flow path by the air supply means, and the atmosphere of the fuel gas flow path is replaced with the air. preferable.
It is preferable that the fuel gas generation unit performs fuel gas generation until the injection of the raw material into the fuel gas channel by the bypass unit is completed.

After the power generation of the fuel cell is completed, the raw material is injected into the fuel gas flow path by the bypass means, and the atmosphere of the fuel gas flow path is replaced with the raw material, and then the fuel gas generation of the fuel gas generation means is stopped. Preferably, the water vapor is injected into the fuel gas generation means by the water vapor supply means to replace the atmosphere inside the fuel gas generation means with the water vapor.
After the power generation of the fuel cell is completed, the fuel gas generation unit stops the fuel gas generation, and the water vapor supply unit injects the water vapor into the fuel gas generation unit, thereby changing the atmosphere inside the fuel gas generation unit. It is preferable to substitute with water vapor, and to inject the raw material into the fuel gas flow path by the bypass means to replace the atmosphere of the fuel gas flow path with the raw material.

Air supply means for supplying air to the fuel gas flow path and the fuel gas generation means to replace the atmosphere of the fuel gas flow path and the atmosphere inside the fuel gas generation means with the air; Injecting the raw material into the fuel gas flow path to replace the atmosphere of the fuel gas flow path with the raw material, and injecting the water vapor into the fuel gas generation means to change the atmosphere inside the fuel gas generation means to the After substituting with water vapor, the air is injected into both the fuel gas flow path and the fuel gas generation means by the air supply means, and the atmosphere of the fuel gas flow path and the atmosphere inside the fuel gas generation means Are preferably replaced with the air.
It is preferable that a desulfurizer for removing sulfur components from the raw material is provided, and the raw material that has passed through the desulfurizer is supplied as the replacement gas by the replacement gas supply means.

Further, the operation method of the fuel cell power generation system of the present invention is a fuel gas that generates a hydrogen-rich fuel gas from a fuel cell having a fuel electrode and an oxidant electrode and a raw material mainly composed of a compound containing carbon and hydrogen. An operation method of a fuel cell power generation system, comprising: a generation means, and a fuel gas supply means for supplying the fuel gas to a fuel gas flow path of the fuel cell; and a water vapor supply means for supplying water vapor to the fuel gas generation means And after stopping the power generation of the fuel cell, the fuel gas generation step by the fuel gas generation means is stopped, and the raw material is injected into the fuel gas flow path as a replacement gas, and the atmosphere of the fuel gas flow path A first replacement step of substituting the raw material with the raw material, and supplying water vapor to the fuel gas generation means by the water vapor supply means, thereby providing an atmosphere inside the fuel gas generation means. Implementing the third replacement step of replacing the air in the water vapor.
An air supply means for supplying air to the fuel gas flow path to replace the atmosphere of the fuel gas flow path with air; and after performing the first replacement step after power generation, the air supply means It is preferable to include a second replacement step of injecting air into the fuel gas flow path to replace the atmosphere of the fuel gas flow path with the air.

It is preferable that the fuel gas is generated in the fuel gas generation unit until the injection of the raw material into the fuel gas flow path in the first replacement step is completed.
It is preferable that the first replacement step is a step of bypassing the fuel gas generation means and supplying the raw material to the fuel gas flow channel to replace the atmosphere of the fuel gas flow channel with the raw material.
An air supply means for supplying air to the fuel gas flow path to replace the atmosphere of the fuel gas flow path with air; and after performing the first replacement step after power generation, the air supply means It is preferable to include a second replacement step of injecting air into the fuel gas flow path to replace the atmosphere of the fuel gas flow path with the air.
It is preferable that the fuel gas is generated in the fuel gas generation unit until the injection of the raw material into the fuel gas flow path in the first replacement step is completed.

  As described above, according to the fuel cell power generation system or fuel cell power generation method of the present invention, in at least one of before the start of power generation and after the end of power generation, in the fuel cell provided with the replacement gas, in particular, the fuel gas generation means, the fuel gas Similar to the gas supplied to the generating means, the residual gas in the fuel gas channel is removed by injecting the raw material mainly composed of carbon and hydrogen as a replacement gas into the fuel gas channel including the fuel electrode. In addition, the atmosphere of the fuel gas passage can be replaced with a replacement gas.

Further, in the fuel cell power generation system or fuel cell power generation method including the air supply means, after replacing the atmosphere of the fuel gas flow path including the fuel electrode of the fuel cell with the replacement gas, the air is supplied to the fuel gas flow by the air supply means. By injecting into the channel, the atmosphere of the gas channel can be replaced with air.
Further, a fuel cell power generation system capable of realizing stable combustion in the burner until the end of the replacement by generating the fuel gas with the fuel gas generating means until the replacement gas injection into the fuel gas flow path including the fuel electrode of the fuel cell is completed. Alternatively, a fuel cell power generation method can be provided.

  Further, by providing the water vapor supply means, the fuel gas generation means stops the fuel gas generation after the replacement gas injection into the fuel gas flow path including the fuel electrode of the fuel cell is completed, and the water vapor supply means supplies the water vapor. By injecting the gas generation means, the fuel gas remaining in the fuel gas generation means can be removed, and the atmosphere inside the fuel gas generation means can be replaced with water vapor.

  In addition, after the power generation of the fuel cell power generation system or the power generation method, the fuel gas generation unit stops the fuel gas generation, the water vapor supply unit injects the water vapor into the fuel gas generation unit, and the replacement gas is supplied to the fuel cell fuel. The fuel gas remaining in the fuel gas generation means is removed by injecting the fuel gas flow path including the electrode, the atmosphere inside the fuel gas generation means is replaced with water vapor, and the fuel remaining in the fuel gas flow path The gas can be removed and the atmosphere of the fuel gas flow path can be replaced with a replacement gas. In addition, the replacement time can be shortened because the replacement is performed independently at the same time.

Also, after injecting a replacement gas into the fuel gas flow path including the fuel electrode of the fuel cell and injecting water vapor into the fuel gas generation means to replace each atmosphere, the fuel gas flow path of the fuel cell and the fuel gas generation By injecting air into both of the means by the air supply means, the atmosphere of the entire raw material and fuel flow paths inside the system can be replaced with air.
Further, the fuel gas generation means includes a shift portion provided with a shift catalyst body made of noble metal and metal oxide, so that even if air enters the fuel gas generation means by air replacement, the shift catalyst body It is possible to prevent the deterioration of performance.

Further, the fuel gas is diffusely diffused by continuously injecting the replacement gas or the raw material into the fuel gas flow path including the fuel electrode until the detection value detected by the carbon monoxide concentration detection means falls below a predetermined value. The amount of replacement gas or raw material injected into the fuel gas flow path can be appropriately controlled.
The replacement gas is a fuel cell that does not contain a sulfur component and can be the same as the raw material by using a replacement gas mainly composed of a compound containing at least carbon and hydrogen such as hydrocarbons. A power generation system or a power generation method can be provided.

  In addition, cylinders are required by using sulfur component removal means to remove sulfur components contained in the raw material or the replacement gas, and using either or both of the raw material and the replacement gas as city gas that is maintained as a social infrastructure. However, it is possible to provide a fuel cell power generation system or power generation method with a simpler configuration.

  A fuel cell power generation system based on a first system of the present invention includes a fuel cell having a fuel electrode and an oxidant electrode, and fuel gas supply means for supplying fuel gas to a fuel gas flow path of the fuel cell including the fuel electrode. An oxidant gas supply means for supplying an oxidant gas to the oxidant gas flow path of the fuel cell including the oxidant electrode, and a replacement gas mainly composed of a compound containing carbon and hydrogen in the fuel gas flow path And after the power generation of the fuel cell is completed, the replacement gas supply means injects the replacement gas into the fuel gas flow path, thereby replacing the atmosphere of the fuel gas flow path with the replacement gas. Configure to replace with gas.

Similarly, in the fuel cell power generation method based on the first method of the present invention, a fuel gas is provided in the fuel gas channel of the fuel cell having a fuel gas channel including a fuel electrode and an oxidant gas channel including an oxidant electrode. And after the completion of power generation of the fuel cell, a replacement gas mainly composed of a compound containing carbon and hydrogen is injected into the fuel gas flow path to change the atmosphere of the fuel gas flow path. A first replacement step of replacing with a replacement gas.
In these power generation systems and power generation methods, after the power generation of the fuel cell is completed, the atmosphere of the fuel gas flow path including the fuel electrode of the fuel cell is purged with a replacement gas, so that the fuel gas remaining inside the fuel cell There is no danger of touching and there is no danger of fuel gas exploding inside the fuel cell.

  In a preferred aspect of the power generation system according to the first system of the present invention, the power generation system further includes air supply means for supplying air to the fuel gas flow path and replacing the atmosphere of the fuel gas flow path with air. After completion, the replacement gas supply means injects the replacement gas into the fuel gas flow path to replace the atmosphere of the fuel gas flow path with the replacement gas, and then the air supply means supplies the fuel gas flow path to the fuel gas flow path. The air is injected to replace the atmosphere of the fuel gas passage with the air.

Similarly, in a preferred mode of the power generation method according to the first system of the present invention, after the power generation is completed, the first replacement step is performed, and then air is injected into the fuel gas flow channel to thereby form the fuel gas flow channel. A second replacement step of replacing the atmosphere with the air.
In these power generation system and power generation method aspects, after purging the atmosphere of the fuel gas flow path including the fuel electrode with the replacement gas and further purging the replacement gas with air, the fuel cell is very Can be held in a safe state. Further, since fuel gas and air do not come into contact with each other, there is no risk of explosion inside the fuel cell.

  In another preferable aspect of the power generation system of the first system of the present invention, the fuel gas supply means generates a fuel gas rich in hydrogen from a raw material mainly composed of a compound containing carbon and hydrogen. And a raw material supply source for supplying the raw material to the fuel gas generating means, and until the replacement gas supply means finishes injecting the replacement gas into the fuel gas flow path, the fuel gas generating means Fuel gas generation is performed.

Similarly, in another preferred embodiment of the power generation method of the first system of the present invention, the fuel gas supply step uses, as a fuel gas, a hydrogen-rich fuel gas from a raw material mainly composed of a compound containing carbon and hydrogen. The fuel gas is generated in the fuel gas generation step until injection of the replacement gas into the fuel gas flow path in the first replacement step is completed.
According to these power generation systems and power generation method aspects, stable combustion in the burner that heats the reaction portion in the fuel gas generation means until the replacement of the atmosphere of the fuel gas flow path including the fuel electrode with the replacement gas is completed, that is, A stable fuel gas generation process can be realized.

  In still another preferred embodiment of the power generation system or power generation method of the first method of the present invention, the fuel generating means for generating hydrogen-rich fuel gas from the raw material mainly containing a compound containing carbon and hydrogen is replaced with water vapor. A water vapor supplying means or a water vapor replacing step (third water replacing step). After the power generation of the fuel cell is completed, the replacement gas supply means injects the replacement gas into the fuel gas flow path including the fuel electrode of the fuel cell and replaces the fuel gas flow path with the replacement gas. The fuel gas generation is stopped and water vapor is injected into the fuel gas generation means by the water vapor supply means. Alternatively, after the power generation of the fuel cell is completed, the fuel gas generation unit stops the fuel gas generation, and the water vapor supply unit injects water vapor into the fuel gas generation unit, and the replacement gas supply unit supplies the replacement gas to the fuel cell. Inject into the fuel gas flow path. That is, the fuel gas generation is stopped, and the third replacement process and the first replacement process are performed.

  According to these aspects of the power generation system or power generation method, the atmosphere inside the fuel gas generation means is purged with water vapor so that almost no combustible gas remains in the fuel gas flow path. By injecting water vapor into the fuel gas generating means, cooling of the fuel gas generating means is promoted, and the time until the end of operation can be shortened. By independently performing the water vapor injection into the fuel gas generating means and the replacement gas injection into the fuel gas flow path including the fuel electrode of the fuel cell, the time for replacement can be shortened.

  In another preferable aspect of the first method of the present invention, air is supplied to a fuel gas flow path including a fuel electrode of a fuel cell and fuel gas generation means, and the atmosphere of the fuel gas flow path and the fuel gas generation An air supply means for substituting the atmosphere inside the means with air, and after supplying the replacement gas to the fuel gas flow path and injecting water vapor into the fuel gas generation means, the fuel gas flow path and the fuel gas generation means Air is injected into the inside by air supply means. As a result, the atmosphere in both the fuel gas flow path and the fuel gas generation means can be replaced with air.

  Here, the air injection by the air supply means is performed in series from the fuel gas generating means to the fuel gas flow path of the fuel cell. Alternatively, air injection by the air supply means is performed in parallel with the fuel gas generation means and the fuel gas flow path of the fuel cell. According to the former, it is possible to replace with air from the upstream side of the fuel gas channel to the downstream side along the channel. Moreover, according to the latter, the whole fuel gas flow path can be substituted with air in a short time.

  Furthermore, in another aspect of the first mode of the present invention, the fuel gas generating means includes a shift section provided with a shift catalyst body comprising at least a noble metal and a metal oxide as a constituent material, and at least the monoxide is formed in the shift section. A hydrogen gas supply unit that supplies hydrogen gas containing carbon and water vapor as subcomponents is provided. As a result, the oxidation resistance inside the fuel gas generating means is increased, so that even if air is injected into the inside, the problem of oxidation hardly occurs.

  A fuel cell power generation system based on the second system of the present invention is a fuel cell that generates a hydrogen-rich fuel gas from a fuel cell having a fuel electrode and an oxidant electrode, and a raw material mainly composed of a compound containing carbon and hydrogen. Generating means, raw material supply source for supplying the raw material to the fuel gas generating means, and fuel gas supplying means for supplying the fuel gas from the fuel gas generating means to a fuel gas flow path of the fuel cell including the fuel electrode And bypass means for bypassing the fuel gas generating means from the raw material supply source and injecting the raw material into the fuel gas flow path as raw material gas, and after the power generation of the fuel cell is completed, the bypass means The raw material gas is injected into the fuel gas flow path, and the atmosphere of the fuel gas flow path is replaced with the raw material gas.

  Similarly, a fuel cell power generation method based on the second method of the present invention includes a fuel gas generation step for generating a hydrogen-rich fuel gas from a raw material mainly composed of a compound containing carbon and hydrogen, and a fuel including a fuel electrode. A fuel gas supply step of supplying the fuel gas to the fuel gas channel of a fuel cell having an oxidant gas channel including a gas channel and an oxidant electrode; and the raw material as a raw material gas directly into the fuel gas channel. A first replacement step of supplying and replacing the atmosphere of the fuel gas flow path with the source gas, and the first replacement step is performed after completion of power generation of the fuel cell.

  In these power generation systems and power generation methods, after the power generation of the fuel cell is completed, the atmosphere of the fuel gas passage including the fuel electrode of the fuel cell is purged with the raw material gas, so that the fuel gas remaining inside the fuel cell is air. There is no danger of touching and there is no risk of the fuel gas exploding inside the fuel cell. In addition, since the gas for purging the atmosphere that requires purging is supplied from the same supply source as the raw material, a simple and efficient system can be obtained.

  In a preferred aspect of the power generation system of the second system of the present invention, the power generation system further comprises air supply means for supplying air to the fuel gas flow path and replacing the atmosphere of the fuel gas flow path with the air, After the end of power generation, the raw material gas is injected into the fuel gas flow path by the bypass means to replace the atmosphere of the fuel gas flow path with the raw material gas, and then the air supply means adds the raw material gas to the fuel gas flow path. Air is injected to replace the atmosphere of the fuel gas flow path with the air.

Similarly, in a preferred aspect of the fuel cell power generation method according to the second method of the present invention, after the first replacement step is performed after the power generation is completed, air is injected into the fuel gas flow path, and the fuel gas flow A second replacement step of replacing the atmosphere of the road with the air;
According to these power generation systems or power generation method aspects, after purging the atmosphere of the fuel gas flow path including the fuel electrode with the raw material gas, the raw material gas is further purged with air. Can be kept in a safe state. Further, since fuel gas and air do not come into contact with each other, there is no risk of explosion inside the fuel cell.

In another preferable aspect of the power generation system of the second system of the present invention, the fuel gas generation means performs the fuel gas generation until the injection of the raw material gas into the fuel gas flow path by the bypass means is completed. Do.
Similarly, in another preferred aspect of the power generation method of the second system of the present invention, in the fuel gas generation step until the injection of the raw material gas into the fuel gas flow path in the first replacement step is completed. Fuel gas is generated.
According to these power generation systems or power generation method aspects, stable combustion in the burner that heats the reaction portion in the fuel gas generation means, that is, stable, is achieved until the replacement of the fuel gas flow path including the fuel electrode with the replacement gas is completed. A fuel gas generation process can be realized.

  In a further preferred aspect of the power generation system of the second system of the present invention, the apparatus further comprises a water vapor supplying means for supplying water vapor to the fuel gas generating means and substituting the atmosphere inside the fuel gas generating means with the water vapor. Then, after the power generation is completed, the raw material gas is injected into the fuel gas flow path by the bypass means, and the atmosphere of the fuel gas flow path is replaced with the raw material gas, and then the fuel gas of the fuel gas generation means The generation is stopped and the water vapor is injected into the fuel gas generation means by the water vapor supply means to replace the atmosphere inside the fuel gas generation means with the water vapor.

  Alternatively, the apparatus further includes water vapor supply means for replacing the atmosphere inside the fuel gas generation means with water vapor, and after the power generation is completed, the fuel gas generation means stops the fuel gas generation, and the water vapor supply means generates the fuel gas. Water vapor is injected into the means, and the raw material gas is injected into the fuel gas flow path by the bypass means to replace the atmosphere in the fuel gas flow path with the raw material gas.

  Similarly, in still another preferable aspect of the power generation method according to the second system of the present invention, the fuel gas generation in the fuel gas generation step is performed using a fuel gas generation unit, and the fuel gas generation unit includes water vapor. And a third substitution step of substituting the atmosphere inside the fuel gas generation means with the water vapor to stop the fuel gas generation step by the fuel gas generation means after completion of the power generation, and Three substitution steps and the first substitution step are performed.

  According to these power generation systems or power generation method aspects, the combustible gas hardly remains in the fuel gas flow path by purging the internal atmosphere of the fuel gas generating means with water vapor. By injecting water vapor into the fuel gas generating means, cooling of the fuel gas generating means is promoted, and the time until the end of the operation can be shortened. The time for replacement can be shortened by independently performing the steam injection into the fuel gas generating means and the replacement gas injection into the fuel gas flow path including the fuel electrode of the fuel cell.

  In still another preferred aspect of the second system of the present invention, air is supplied to the fuel gas flow path and the fuel gas generation means, and the atmosphere of the fuel gas flow path and the inside of the fuel gas generation means Air supply means for substituting the atmosphere with the air, supplying the source gas to the fuel gas flow path to replace the atmosphere in the fuel gas flow path with the source gas, and the fuel After injecting the water vapor into the gas generation means and replacing the atmosphere inside the fuel gas generation means with the water vapor, the air supply means both the fuel gas flow path and the fuel gas generation means by the air supply means. Air is injected to replace the atmosphere in the fuel gas flow path and the atmosphere in the fuel gas generation means with the air.

Thereby, the whole flow path of the raw material and fuel gas inside the system can be replaced with air.
Here, in a preferred aspect of air injection by the air supply means, the fuel gas generation means is connected in series to the fuel gas flow path. Alternatively, in another preferable aspect of air injection by the air supply means, the fuel gas generation means and the fuel gas flow path are performed in parallel.
According to the former, it is possible to replace with air from the upstream side of the fuel gas channel to the downstream side along the channel. Moreover, according to the latter, the whole fuel gas flow path can be substituted with air in a short time.

  In another aspect of the second mode of the present invention, the fuel gas generating means includes a shift portion provided with a shift catalyst body having at least a noble metal and a metal oxide as constituent materials, and at least the carbon monoxide in the shift portion. And a hydrogen gas supply unit for supplying hydrogen gas containing water vapor as subcomponents. As a result, the oxidation resistance inside the fuel gas generating means is increased, so that even if air is injected into the inside, the problem of oxidation hardly occurs.

  According to each aspect and each aspect of the present invention described above, the method further comprises a carbon monoxide concentration detecting means for detecting a carbon monoxide concentration contained in the fuel gas generated in the fuel gas generating means, Until the detection value detected by the carbon monoxide concentration detection means falls below a predetermined value, the replacement gas or the raw material gas as the replacement gas is injected into the fuel gas flow path including the fuel electrode. As a result, it is possible to prevent the problem that the fuel gas containing high-concentration carbon monoxide flows into the fuel gas flow path due to diffusion and poisons the fuel electrode in the initial operation of the fuel gas generating means.

Moreover, in each system and each aspect of the present invention, a preferred replacement gas does not contain a sulfur component. As a result, poisoning of the fuel electrode catalyst can be prevented.
Furthermore, in each system and each aspect of the present invention, a preferable raw material supplied from a raw material supply source is a gas obtained by removing a sulfur component contained in a city gas. Thereby, while being able to use a raw material simply, poisoning of the catalyst of a fuel electrode can be prevented.
Embodiments of the present invention will be described below with reference to the drawings.

Embodiment 1
FIG. 1 shows a configuration of a fuel cell power generation system according to Embodiment 1 of the present invention. The fuel cell power generation system in the present embodiment includes a fuel cell 11, a fuel supply unit that supplies fuel gas to the fuel electrode 11a of the fuel cell, an oxidant gas supply unit that supplies oxidant gas to the oxidant electrode of the fuel cell, and A desulfurization gas supply pipe 12 for supplying a desulfurization gas from which the sulfur component has been removed from the city gas to the fuel gas supply pipe 10 as a replacement gas is provided. This replacement gas contains a compound containing carbon and hydrogen such as hydrocarbon as a main component.

  Further, the desulfurization gas supply pipe 12 is provided with a desulfurizer 13 that removes sulfur components from the raw material of the replacement gas containing sulfur components such as city gas, and an opening / closing valve 14 for supplying / blocking the desulfurization gas. In this embodiment, city gas which has as a main component a compound containing carbon and hydrogen is used as a raw material. The typical city gas is mostly methane and partly contains butane.

  The operation of the fuel cell power generation system in this embodiment will be described. When power generation is performed, first, the on-off valve 14 is opened, and the desulfurized gas from which the sulfur component of the city gas is removed by the desulfurizer 13 is injected from the desulfurized gas supply pipe 12 into the fuel electrode 11a of the fuel cell 11 through the fuel gas supply pipe 10. . Thereby, the gas remaining in the fuel electrode of the fuel cell and the vicinity thereof is discharged to the outside of the fuel cell 11, and the atmosphere of the fuel gas flow path inside the fuel cell including the fuel electrode 11a is purged with the desulfurization gas. In addition, in this specification, purge means discharging, and in other words, means replacing an existing substance such as a gas existing in a certain space with a substance such as a purge gas. .

  When purging of the atmosphere inside the fuel gas flow path including the fuel electrode 11a with the desulfurization gas is completed, the on-off valve 14 is closed to stop the supply of the desulfurization gas, and the fuel cell 11 is supplied with the fuel gas and the oxidant gas to generate power. . When stopping power generation, the supply of fuel gas and oxidant gas to the fuel cell 11 is first stopped. Next, the on-off valve 14 is opened, and the desulfurized gas is injected into the fuel electrode 11a of the fuel cell 11 to discharge the unreacted fuel gas to the outside of the fuel cell 11 as before the power generation. The internal atmosphere of the fuel gas flow path of the fuel cell containing 11a is purged with desulfurized gas.

  The fuel gas supplied to the fuel electrode 11a of the fuel cell 11 is a hydrogen-rich gas and may explode if it comes into direct contact with air. When the power generation of the fuel cell 11 has been stopped for a while, external air flows into the fuel electrode 11a of the fuel cell 11 from a tube or the like. However, if the configuration of the fuel cell power generation system shown in the present embodiment is taken, the atmosphere of the fuel gas flow path including the fuel electrode 11a of the fuel cell 11 is first purged with desulfurization gas before the start of power generation, and then the fuel gas is removed. After the fuel cell 11 is supplied to the fuel electrode 11a of the fuel cell 11 and the supply of the fuel gas to the fuel electrode 11a of the fuel cell 11 is stopped at the end of power generation, the fuel gas flow path including the fuel electrode 11a of the fuel cell 11 with desulfurized gas is used. Purge the atmosphere.

Therefore, there is no danger that the fuel gas remaining inside the fuel cell 11 will come into contact with air, and there is no possibility that the fuel gas will explode inside the fuel cell 11. That is, according to the configuration of the fuel cell power generation system shown in the present embodiment, safe start / stop can be realized without nitrogen supply in power generation of the fuel cell.
In general, it is known that in a mixed gas of hydrogen gas and air, a range of 4 to 75% by volume of hydrogen gas is a combustible range. In some cases, even if in the combustible range, it may not burn or explode, but the occurrence of the combustible state should be avoided. Therefore, it is necessary to pay attention so that such hydrogen gas does not enter the combustible range even during the above-described purge process or during the purge process of the following embodiment.

  Here, the purge process has been described in which the atmosphere of the fuel gas passage including the fuel electrode of the fuel cell is purged with desulfurized gas both before the start of power generation and after the end of power generation. However, for the purge only before the start of power generation, the purge effect before the start of power generation shown in the above description of the operation, and for the purge only after the end of power generation, the purge effect after the end of the power generation shown in the description of the operation, Each is obtained independently.

<< Embodiment 2 >>
FIG. 2 is a configuration diagram showing a fuel cell power generation system according to Embodiment 2 of the present invention. The fuel cell power generation system according to this embodiment includes a fuel cell 11 that generates power using a fuel gas and an oxidant gas, a compound containing carbon and hydrogen such as hydrocarbons represented by city gas as main components, and sulfur. And a desulfurizer 16 for removing sulfur components from the gas as a raw material containing the components.

  In this embodiment, city gas is used as the source gas. The fuel cell power generation system according to the present embodiment further includes a reaction unit 15a that generates hydrogen-rich fuel gas by steam reforming the desulfurized city gas and a burner 15b as a heating unit for performing the reforming reaction. The fuel gas generator 15 to be supplied, the fuel gas supply pipe 19 for supplying the fuel gas to the fuel cell 11, the residual fuel gas pipe 20 for supplying the residual fuel gas to the burner 15b, and the oxidant gas to the fuel cell 11 As a blower 17 for supplying air, and a desulfurization gas supply pipe 12 for supplying a desulfurization gas from which sulfur components have been removed from the city gas to a fuel gas supply pipe 19. Further, the desulfurization gas supply pipe 12 is provided with a desulfurizer 13 for removing sulfur components from the city gas, and an opening / closing valve 14 for supplying / blocking the desulfurization gas.

  Further, a fuel cell bypass pipe 21 from the fuel gas supply pipe 19 to the remaining fuel gas pipe 20 is provided, and the fuel gas from the fuel gas generation unit 15 is supplied to the fuel cell 11 by the flow path switching valve 18, or the fuel cell. Exhaust is performed from the bypass pipe 21. Further, an on-off valve 22 is provided upstream from the junction of the residual fuel gas pipe 20 with the fuel cell bypass pipe 21. Further, if necessary, the carbon monoxide concentration detection means 32 for detecting the carbon monoxide concentration in the fuel gas generated by the fuel gas generation unit 15, and the detection value detected by the carbon monoxide concentration detection means 32. And a control unit 33 for controlling the opening and closing of the on-off valve 14 based on the control unit 33.

The fuel cell power generation system in the present embodiment shown in FIG. 2 and the flow chart of the first example of the start-up method including the purge step with the specific desulfurization gas of the present embodiment shown in FIG. An example of the startup operation of the battery power generation system will be described. Before starting the power generation of the fuel cell power generation system, the flow path switching valve 18 first switches the flow path so that the fuel gas flows through the fuel cell bypass pipe 21. Next, the on-off valves 14 and 22 are opened, and the desulfurization gas from which the sulfur component has been removed from the city gas by the desulfurizer 13 is injected from the desulfurization gas supply pipe 12 into the fuel gas supply pipe 19. 11a and the internal atmosphere of the fuel gas supply pipe 19 downstream of the flow path switching valve 18 and the internal atmosphere of the residual fuel gas pipe 20 upstream of the on-off valve 22 are purged with desulfurization gas.

  When the purge with the desulfurization gas is completed, the on-off valves 14 and 22 are closed. Thereafter, the desulfurized gas from which the sulfur component has been removed by the desulfurizer 16 is supplied to the fuel gas generation unit 15, and after the fuel gas component becomes ready for power generation by the fuel cell 11, the on-off valve 22 is opened, The fuel gas flow path is connected to the fuel cell 11 by the path switching valve 18, and the fuel gas is supplied to the fuel electrode 11 a of the fuel cell 11. At the same time, air is generated by supplying air to the air electrode of the fuel cell 11 by the blower 17.

  The fuel gas supplied to the fuel electrode 11a of the fuel cell 11 is a hydrogen-rich gas and may explode if it comes into direct contact with air. However, if the purge process in the present embodiment is performed, the fuel gas flow path between the flow path switching valve 18 and the on-off valve 22 is purged with desulfurization gas before the start of power generation, and then the fuel gas is fueled during power generation. Power is generated by supplying the fuel electrode 11a of the battery 11.

  Therefore, even if air is contained in the gas remaining in the fuel electrode 11a of the fuel cell 11 before the start of operation, that is, before the purge process, there is no danger of contact with the air and the fuel gas. There is no danger of explosion inside. That is, according to the configuration of the fuel cell power generation system shown in the present embodiment and the purge process of the atmosphere of the fuel gas flow path by the specific desulfurization gas of the present embodiment, a safe start-up in the operation of the fuel cell power generation system Can be realized without.

  Next, referring to the fuel cell power generation system having the configuration shown in FIG. 2 and the flowchart of the operation stop method including the purging step by the desulfurization gas of the present embodiment shown in FIG. 4, the operation of the fuel cell power generation system in the second embodiment will be described. An example of the stop operation will be described. At the end of power generation in the fuel cell power generation system, the fuel gas flow path is first connected to the fuel cell bypass pipe 21 by the flow path switching valve 18, and the supply of the city gas as the raw material gas is stopped. Next, the on-off valve 14 is opened, desulfurized gas is injected into the fuel gas supply pipe 19, and the atmosphere of the flow path from the flow path switching valve 18 to the on-off valve 22 is purged with desulfurized gas.

  When this purge process is completed, the on-off valve 14 and the on-off valve 22 are closed, and the operation is terminated. The fuel gas supplied to the fuel electrode 11a of the fuel cell 11 is a hydrogen-rich gas and may explode if it comes into direct contact with air. However, when the purge process in the present embodiment is performed, after the power generation is completed, the supply of the fuel gas to the fuel electrode 11a of the fuel cell 11 is stopped, and then the flow from the flow path switching valve 18 to the on-off valve 22 with desulfurized gas. Therefore, the fuel gas hardly remains in the fuel electrode 11a of the fuel cell 11.

Therefore, even if air flows into the fuel electrode 11 a of the fuel cell 11, there is no risk of explosion inside the fuel cell 11 because no fuel gas remains. That is, according to the configuration of the fuel cell shown in the present embodiment and the specific purging process of the present embodiment, a safe shutdown can be realized without supplying nitrogen in the operation of the fuel cell power generation system.
In this purge process, the on-off valve 22 is closed when the purge is completed. However, the operation may be terminated with the on-off valve 22 opened.

  Next, referring to the fuel cell power generation system of this embodiment shown in FIG. 2 and the flowchart of the second example of the start-up method including the specific desulfurization gas purging step of this embodiment shown in FIG. Another example of the starting operation of the fuel cell power generation system in the embodiment will be described. In this fuel cell power generation system, the on-off valve 22 is not always necessary. However, in the description of the operation, a description will be given of a configuration in which the on-off valve 22 is always opened.

  Before starting the power generation of the fuel cell power generation system, the flow path switching valve 18 first switches the flow path so that the fuel gas flows through the fuel cell bypass pipe 21. Next, the on-off valve 14 is opened, and the desulfurization gas from which the sulfur component has been removed from the city gas by the desulfurizer 13 is injected from the desulfurization gas supply pipe 12 into the fuel gas supply pipe 19. The internal atmosphere of the fuel gas supply pipe 19 downstream of the flow path switching valve 18 and the internal atmosphere of the residual fuel gas pipe 20 upstream of the on-off valve 22 are purged with desulfurized gas.

  When the purging step with the desulfurization gas is completed, the desulfurization gas from which the sulfur component has been removed by the desulfurizer 16 is supplied to the fuel gas generation unit 15, and after the fuel gas component is in a state where the fuel cell 11 can generate power, By closing the on-off valve 14, the supply of desulfurized gas is stopped. Next, power is generated by supplying fuel gas to the fuel cell 11 through the flow path switching valve 18 and simultaneously supplying air to the fuel cell 11 through the blower 17.

  When the starting method described based on the flowchart of the second example is performed, the following effects are obtained in addition to the effects described in the electromotive method shown in the flowchart of the first example of FIG. That is, when the fuel cell power generation system is started, the fuel gas generated by the fuel gas generation unit 15 contains high-concentration carbon monoxide, and if it flows into the fuel electrode, it poisons the fuel electrode. become. However, as described above, since desulfurization gas is injected into the fuel gas supply pipe 19 at the time of start-up, the fuel electrode containing high-concentration carbon monoxide passes through the on-off valve 22 being released from the fuel cell bypass pipe 21 and then the fuel electrode. It is possible to prevent diffusive inflow into the water.

Therefore, according to the starting method of the specific example of the present embodiment, in the operation of the fuel cell power generation system, safe starting can be realized without supplying nitrogen, and the fuel electrode 11a of the fuel cell 11 at the time of starting is oxidized. Preventing carbon poisoning can be realized.
In the fuel cell power generation system, the carbon monoxide concentration detection means 32 for detecting the carbon monoxide concentration in the fuel gas generated by the fuel gas generation unit 15 and the carbon monoxide concentration detection are further provided as necessary. A control unit 33 is further provided for controlling the opening / closing of the on-off valve 14 based on the detection value detected by the means 32.

The on-off valve 14 is opened until the detection value detected by the carbon monoxide concentration detection means 32 falls below a predetermined value, and desulfurized gas is injected into the fuel electrode 11a. After the detected amount falls below the predetermined value, the on-off valve 14 is turned off. By setting the control unit 33 to stop the injection of the desulfurization gas as closed, it is possible to prevent carbon monoxide from flowing into the fuel cell 11 in a diffusive manner, and to appropriately manage the use amount of the desulfurization gas. .
In the above description of the operation, the on-off valve 22 is always open. However, the same effect can be obtained with the configuration in which the on-off valve 22 is removed, and the cost can be reduced by reducing the number of parts.

<< Embodiment 3 >>
FIG. 6 is a configuration diagram showing a fuel cell power generation system according to Embodiment 3 of the present invention. Constituent elements similar to those shown in FIG. 23, a desulfurization gas obtained by removing the sulfur component from the gas as a raw material containing a sulfur component and a main component of a carbon and hydrogen compound such as a hydrocarbon represented by city gas is supplied to the fuel gas generation unit 15. It is a fuel gas generation unit bypass pipe for bypassing and supplying directly to the fuel cell 11. In this embodiment, city gas is used as source gas.

  The fuel gas generation unit bypass pipe 23 includes an on-off valve 24. Further, the pipe for supplying the desulfurized gas as the raw material gas to the fuel gas generating unit 15 has a raw material gas supply valve 25 for supplying and stopping the raw material gas. Further, if necessary, the carbon monoxide concentration detection means 32 for detecting the carbon monoxide concentration in the fuel gas generated by the fuel gas generation unit 15, and the detection value detected by the carbon monoxide concentration detection means 32. And a control unit 34 for controlling the opening and closing of the on-off valve 24 based on the control unit 34.

  An example of the electromotive operation of the fuel cell power generation system according to the third embodiment will be described with reference to the flowchart of the first example of the specific power generation method shown in FIG. 7 and the fuel cell power generation system shown in FIG. Before starting the power generation of the fuel cell power generation system, the flow path switching valve 18 first switches the flow path so that the fuel gas flows through the fuel cell bypass pipe 21. Subsequently, the on-off valve 24 and the on-off valve 22 are opened, the raw material gas supply valve 25 is closed, and the desulfurized gas from which the sulfur component has been removed from the raw gas such as city gas by the desulfurizer 16 is supplied to the fuel gas generator bypass pipe 23. Are injected into the fuel gas supply pipe 19 from the fuel electrode 11a, the internal atmosphere of the fuel gas supply pipe 19 downstream of the flow path switching valve 18, and the residual fuel gas pipe 20 upstream of the on-off valve 22. Purge the internal atmosphere with desulfurization gas.

  When the purge process with the desulfurized gas is completed, the on-off valve 24 and the on-off valve 22 are closed, and then the raw material gas supply valve 25 is opened to supply the raw material gas to the fuel gas generating unit 15. After the fuel gas component becomes ready for power generation by the fuel cell 11, the on-off valve 22 is opened, the fuel gas is supplied to the fuel cell 11 by the flow path switching valve 18, and at the same time the air is fueled by the blower 17. Power is generated by supplying the battery 11.

  When the purge step using the desulfurization gas is performed, the atmosphere of the fuel gas flow path from the flow path switching valve 18 to the on-off valve 22 is purged with the desulfurization gas before the start of power generation, and then the fuel gas is supplied to the fuel cell during power generation. 11 is supplied to the fuel electrode 11a of the fuel cell 11 to generate electric power. Even if air is contained in the gas remaining in the fuel gas flow path including the fuel electrode 11a of the fuel cell 11 before the start of operation, that is, before the purge process, There is no danger of contact between the air and the fuel gas, thereby preventing the fuel gas from exploding inside the fuel cell 11.

  Furthermore, a simpler and more effective system can be realized by using desulfurization gas for purging the atmosphere that requires purging from the same supply source as the raw material gas. That is, according to the configuration of the fuel cell power generation system shown in the present embodiment and the specific purge process of the present embodiment, in the operation of the fuel cell power generation system, a more effective system and safe startup can be realized without supplying nitrogen. be able to.

  Next, referring to the fuel cell power generation system of this embodiment shown in FIG. 6 and the flowchart of the first example of the specific operation stop method of this embodiment shown in FIG. 8, the fuel cell power generation system in this embodiment will be described. An example of the operation stop operation will be described. At the end of power generation in the fuel cell power generation system, first, the flow path switching valve 18 connects the fuel gas flow path to the fuel cell bypass pipe 21 and closes the raw material gas supply valve 25 to stop the supply of the raw material gas. Next, the on-off valve 24 is opened, and the desulfurized gas desulfurized by the desulfurizer 16 is injected into the fuel gas supply pipe 19 from the fuel gas generation unit bypass pipe 23, and the fuel gas between the flow path switching valve 18 and the on-off valve 22. Purge the flow path atmosphere with desulfurization gas.

  When this purge process is completed, the on-off valve 24 and the on-off valve 22 are closed, and the operation is finished. The fuel gas supplied to the fuel electrode 11a of the fuel cell 11 is a hydrogen-rich gas and may explode if it comes into direct contact with air. However, when the purge step is performed, after the power generation is completed, the supply of the fuel gas to the fuel electrode 11a of the fuel cell 11 is stopped, and then the desulfurization gas is used between the flow path switching valve 18 and the on-off valve 22. Since the atmosphere in the fuel gas passage is purged, the fuel gas hardly remains in the fuel electrode 11a of the fuel cell 11. For this reason, even if air flows into the fuel electrode 11 a of the fuel cell 11, there is no risk of explosion inside the fuel cell 11 because no fuel gas remains.

That is, according to the configuration of the fuel cell and the specific purging process shown in the present embodiment, a safe shutdown can be realized without supplying nitrogen in the operation of the fuel cell power generation system.
In this purge process, the on-off valve 22 is closed when the purge is completed. However, the operation may be terminated with the on-off valve 22 opened.

  Next, referring to the fuel cell power generation system of this embodiment shown in FIG. 6 and the flowchart of the second example of the specific operation stop method of this embodiment shown in FIG. 9, the fuel cell power generation system in this embodiment will be described. Another example of the operation stop operation will be described. At the end of power generation of the fuel cell power generation system, the fuel gas flow path is first connected to the fuel cell bypass pipe 21 by the flow path switching valve 18, and the raw material gas supply valve 25 is kept open to continue the supply of the raw material gas. Generate. Next, the on-off valve 24 is opened, and the desulfurized gas desulfurized by the desulfurizer 16 is injected into the fuel gas supply pipe 19 from the fuel gas generation unit bypass pipe 23, and the fuel gas between the flow path switching valve 18 and the on-off valve 22. Purge the flow path atmosphere with desulfurization gas.

  When this purge process is completed, the source gas supply valve 25 is closed, the supply of the source gas is stopped, the on-off valve 24 and the on-off valve 22 are closed, and the operation is finished. The fuel gas supplied to the fuel electrode 11a of the fuel cell 11 is a hydrogen-rich gas and may explode if it comes into direct contact with air. However, when the purge process in the present embodiment is performed, after the power generation is completed, the supply of the fuel gas to the fuel electrode 11a of the fuel cell 11 is stopped, and then the flow from the flow path switching valve 18 to the on-off valve 22 with desulfurized gas. Therefore, the fuel gas hardly remains in the fuel electrode 11a of the fuel cell 11.

For this reason, even if air flows into the fuel electrode 11 a of the fuel cell 11, there is no risk of explosion inside the fuel cell 11 because no fuel gas remains. Moreover, since both desulfurization gas and source gas return to the burner 15b, the burner 15b can implement | achieve stable combustion, without misfiring.
That is, according to the configuration of the fuel cell shown in the present embodiment and the specific purge process of the present embodiment, in the operation of the fuel cell power generation system, a safe shutdown is realized without supplying nitrogen, and a stable burner at the end Combustion can be realized.
In this purge process, the on-off valve 22 is closed when the purge is completed. However, the operation may be terminated with the on-off valve 22 opened.

  Next, referring to the fuel cell power generation system of the third embodiment shown in FIG. 6 and the flowchart of the second example of the specific power generation method of the present embodiment shown in FIG. 10, the fuel cell power generation in the present embodiment will be described. Another example of the electromotive operation of the system will be described. The fuel cell power generation system does not require the on-off valve 22. However, in the description of the operation, a description will be given of a configuration in which the on-off valve 22 is always opened.

  Before starting the power generation of the fuel cell power generation system, the flow path switching valve 18 first switches the flow path so that the fuel gas flows through the fuel cell bypass pipe 21. Next, the on-off valve 24 is opened, the raw material gas supply valve 25 is closed, and the desulfurized gas from which the sulfur component is removed from the city gas by the desulfurizer 16 is injected into the fuel gas supply pipe 19 from the fuel gas generation unit bypass pipe 23. The internal atmosphere of the fuel gas supply pipe 19 downstream of the fuel cell 11 and the flow path switching valve 18 and the internal atmosphere of the residual fuel gas pipe 20 upstream of the on-off valve 22 are purged with desulfurized gas.

  When the purge step with the desulfurization gas is completed, the raw material gas supply valve 25 is then opened, and the desulfurization gas from which the sulfur component is removed from the gas as the raw material such as city gas by the desulfurizer 16 is supplied to the fuel gas generation unit 15. . In this embodiment, city gas is used as source gas. After the fuel gas component generated by the fuel gas generation unit 15 is in a state in which the fuel cell 11 can generate power, the supply of the desulfurized gas to the fuel gas supply pipe 19 is stopped by closing the on-off valve 24. On the other hand, the flow path switching valve 18 is switched to supply the fuel gas from the fuel gas generator 15 to the fuel cell 11, and at the same time, air is supplied to the fuel cell 11 by the blower 17 to generate power.

  When another example of the starting method according to the flowchart of the second example in the present embodiment is performed, the following effects are obtained in addition to the effect described in the electromotive method shown in the flowchart of the first example in FIG. That is, when the fuel cell system is started, the fuel gas generated by the fuel gas generation unit 15 contains high concentration of carbon monoxide, but desulfurization gas, which is a specific operation of the present invention, is supplied to the fuel gas supply pipe. By injecting the fuel gas into the fuel cell 19, it is possible to prevent the fuel gas from diffusingly flowing into the fuel electrode 11 a of the fuel cell 11.

Therefore, the specific power generation method of the present embodiment based on the above-described another example can realize safe startup without supplying nitrogen in the operation of the fuel cell power generation system, and the fuel of the fuel cell 11 at the time of startup. It is possible to prevent carbon monoxide poisoning of the electrode 11a.
In the fuel cell power generation system, the carbon monoxide concentration detection means 32 for detecting the carbon monoxide concentration in the fuel gas generated by the fuel gas generation unit 15 and the carbon monoxide concentration detection are further provided as necessary. A control unit 34 for controlling opening / closing of the on-off valve 24 based on a detection value detected by the means 32 is further provided.

The on-off valve 24 is opened until the detected value detected by the carbon monoxide concentration detecting means 32 falls below a predetermined value, and desulfurized gas is injected into the fuel electrode 11a. After the detected amount falls below the predetermined value, the on-off valve 24 is turned off. By setting the control unit 34 to stop the injection of the desulfurization gas as closed, it is possible to prevent carbon monoxide from flowing into the fuel cell 11 in a diffusive manner, and to appropriately manage the amount of use of the desulfurization gas. .
In the above description of the operation, the on-off valve 22 is always open. However, the same effect can be obtained with the configuration in which the on-off valve 22 is removed, and the cost can be reduced by reducing the number of parts.

<< Embodiment 4 >>
FIG. 11 is a configuration diagram showing a fuel cell power generation system according to Embodiment 4 of the present invention. Constituent elements similar to those shown in FIG. In the present embodiment, a blower 26 for supplying air to the desulfurized gas supply pipe 12 downstream of the on-off valve 14 and an on-off valve 27 for shutting off the air supply path are further provided.

  With reference to the fuel cell power generation system shown in FIG. 11 and the flowchart of the specific operation stop method shown in FIG. 12, the operation stop operation of the fuel cell power generation system in this embodiment will be described. However, since the operation in the present embodiment is an operation performed after the operation of the system based on the operation stop method shown in the flowchart of FIG. 4 in the second embodiment, the operation of the fuel gas flow path including the fuel electrode 11a of the fuel cell 11 is performed. An explanation will be given after purging with the desulfurization gas of the atmosphere.

  When the purging step using the desulfurization gas is completed, the on-off valve 14 is closed, the on-off valve 27 is opened, and air is injected from the desulfurization gas supply pipe 12 into the fuel gas supply pipe 19 by the blower 26, thereby opening and closing from the flow path switching valve 18. The atmosphere of the fuel gas flow path up to the valve 22 is purged with air. When the air purge is completed, the blower 26 is stopped, the open / close valve 27 is closed, and the system operation is terminated.

  When the purge process in this embodiment is performed, the atmosphere of the fuel gas flow path from the flow path switching valve 18 to the on-off valve 22 is first purged with desulfurization gas, and then the desulfurization gas atmosphere in the same section is purged with air. Therefore, the fuel cell 11 can be held in a very safe state at the end of the operation. Further, since the fuel gas and air do not come into contact with each other, there is no risk of explosion inside the fuel cell 11. That is, the configuration of the fuel cell power generation system and the specific purge process of the present embodiment shown in the present embodiment realize a safe shutdown without nitrogen supply in the operation of the fuel cell power generation system, and at the time of the shutdown Safe holding of the fuel cell 11 can be realized.

<< Embodiment 5 >>
FIG. 13 is a configuration diagram showing a fuel cell power generation system according to Embodiment 5 of the present invention. Constituent elements similar to those shown in FIG. In the present embodiment, a water vapor generator 28 is further provided as means for purging the internal atmosphere of the fuel gas generator 15 with water vapor.

  With reference to the fuel cell power generation system shown in FIG. 13 and the flowchart of the first example of the specific operation stop method shown in FIG. 14, an example of the operation stop operation of the fuel cell power generation system in this embodiment will be described. However, the operation stop operation described in this specific example is an operation performed after the purge step described in the operation stop method shown in the flowchart of FIG. 9 in the third embodiment. Therefore, description will be made after the purging step with the desulfurization gas in the atmosphere of the fuel gas passage including the fuel electrode 11a of the fuel cell 11.

  When the purge step of the fuel gas flow path with the desulfurized gas is completed, the source gas supply valve 25 is closed, and then the on-off valve 24 and the on-off valve 22 are closed. Thereafter, water vapor is supplied from the water vapor generator 28 to the fuel gas generator 15 and the internal atmosphere is purged with water vapor. When the purge process using steam is completed, the steam generator 28 is stopped and the operation is terminated. When the purging process in the present embodiment is performed, the following effects can be obtained in addition to the effects described in the third embodiment whose flowchart is shown in FIG.

  First, since the internal atmosphere of the fuel gas generating unit 15 is purged with water vapor, almost no combustible gas remains in the fuel gas flow path. Further, by injecting water vapor into the fuel gas generation unit 15, the cooling of the fuel gas generation unit 15 is promoted, and the time until the end of the operation can be shortened. That is, the configuration of the fuel cell power generation system and the specific purge process of the present embodiment shown in the present embodiment realize a safe shutdown without nitrogen supply in the operation of the fuel cell power generation system, and stable at the end. It is possible to realize burner combustion and to remove combustible gas in the fuel gas flow path. Furthermore, the time until the end of operation can be shortened. In this purging step, the on-off valve 22 is closed at the end of the operation, but the operation may be terminated particularly with the on-off valve 22 opened.

  Next, referring to the fuel cell power generation system shown in FIG. 13 and the flowchart of the second example of the specific operation stop method shown in FIG. 15, another example of the operation stop operation of the fuel cell power generation system in this embodiment will be described. explain. At the end of power generation in the fuel cell power generation system, the fuel gas flow path is first connected to the fuel cell bypass pipe 21 by the flow path switching valve 18, the raw material gas supply valve 25 is closed, and the supply of the raw material gas is stopped. Next, water vapor is supplied from the water vapor generator 28 to the fuel gas generator 15 and the internal atmosphere is purged with water vapor.

  On the other hand, for the fuel cell 11, the open / close valve 24 is opened at the end of power generation, and the desulfurized gas desulfurized by the desulfurizer 16 is injected from the fuel gas generation unit bypass pipe 23 into the fuel gas supply pipe 19. The flow path atmosphere up to the on-off valve 22 is purged with desulfurization gas. When the purging with water vapor in the flow path from the fuel gas generation unit 15 to the fuel cell bypass pipe 21 is completed, the water vapor generator 28 is stopped and the purging with water vapor is ended. When purging with the desulfurization gas in the flow path atmosphere between the flow path switching valve 18 and the on-off valve 22 is completed, the source gas supply valve 25 is closed to stop the supply of city gas as the source gas, and the on-off valve 24 And the on-off valve 22 is closed and the purge with the desulfurization gas is completed.

  When the purge process in the present embodiment is performed, the following effects can be obtained in addition to the effects described in the third embodiment. First, since the internal atmosphere of the fuel gas generating unit 15 is purged with water vapor, almost no combustible gas remains in the fuel gas flow path. Further, by injecting water vapor into the fuel gas generation unit 15, the cooling of the fuel gas generation unit 15 is promoted, and the time until the end of the operation can be shortened. In addition, since the internal atmospheres of the two reaction units, the fuel gas generation unit 15 and the fuel cell 11, can be purged independently at the same time, the time until the end of the operation can be further shortened.

  That is, the configuration of the fuel cell power generation system and the specific purge process of the present embodiment shown in this embodiment realize a safe shutdown without nitrogen supply in the operation of the fuel cell power generation system, and the fuel gas flow path It is possible to remove the combustible gas inside. Furthermore, since the internal atmospheres of the two reaction sections are simultaneously and independently purged, the time until the end of the operation can be shortened. In this purge process, the on-off valve 22 is closed when the purge process using the desulfurization gas is completed. However, the operation may be terminated with the on-off valve 22 opened.

Embodiment 6
FIG. 16 is a configuration diagram showing a fuel cell power generation system according to Embodiment 6 of the present invention. Constituent elements similar to those shown in FIG. In the present embodiment, a desulfurization gas supply valve 29 that supplies and stops the desulfurization gas, a blower 30 that supplies air upstream of the fuel gas generation unit 15, and an on-off valve 31 that shuts off the air supply path are further provided.

  The operation of the fuel cell power generation system according to this embodiment will be described with reference to the fuel cell power generation system shown in FIG. However, the feature of the operation in the present embodiment resides in the operation performed in the fifth embodiment after the purging step using the desulfurization gas and water vapor described with reference to the flowchart of FIG. 14 or FIG. Therefore, a description will be given later after the purging of the internal atmosphere of the fuel gas generation unit 15 with water vapor and the purging step with the desulfurization gas of the fuel gas passage atmosphere including the fuel electrode 11a of the fuel cell 11.

  When the purge step with water vapor is completed, the desulfurization gas supply valve 29 is closed. Thereafter, the blower 30 is operated and the on-off valve 31 is opened to supply air to the fuel gas generation unit 15, thereby removing water vapor remaining in the fuel gas generation unit 15 into the fuel gas supply pipe 19. Further, air is supplied to the fuel electrode 11 a of the fuel cell 11 using the blower 30. As a result, it is possible to safely purge the atmosphere of the fuel gas flow path downstream from the desulfurization gas supply valve 29 with air, and it is possible to realize the safe holding of the fuel cell 11 when the operation is stopped. Further, since the purge is performed with air, the fuel gas flow path downstream from the source gas supply valve 29 can be opened to the atmosphere, and even if the fuel gas generation unit 15 causes a pressure drop due to a temperature drop, the air is discharged from the atmosphere. It is relieved by inhaling.

  Next, as a more effective purge step with air, referring to the fuel cell power generation system shown in FIG. 16 and the flowchart of the first example of the specific operation stop method shown in FIG. An example of the operation stop operation of the power generation system will be described. When the purge of the internal atmosphere of the fuel gas generation unit 15 with water vapor and the purge of the fuel gas flow path atmosphere including the fuel electrode 11a of the fuel cell 11 with the desulfurization gas are completed, the desulfurization gas supply valve 29 is closed. Next, the on-off valves 31 and 22 are opened, and the flow path is connected to the fuel cell 11 by the flow path switching valve 18. Thereafter, the blower 30 is operated, and air is purged with air by flowing air from the fuel gas generator 15 through the fuel electrode 11a of the fuel cell 11 to the burner 15b.

  After the purge process is finished, the blower 30 is stopped and the on-off valve 31 is closed to finish the operation. In this purging step, air for purging the atmosphere that requires purging is supplied from the upstream side of the fuel gas generation unit 15 and does not branch the flow path. Therefore, the atmosphere can be purged with air sequentially from the upstream side of the fuel gas channel to the downstream side along the channel. That is, the configuration of the fuel cell power generation system shown in the present embodiment and the purging process of this specific example have the same effects as the fuel cell power generation system described in the beginning of the sixth embodiment, and the flow path from the upstream of the fuel gas flow path. And purging the atmosphere downstream with the air.

  Next, as another method of more effective air purging process, refer to the fuel cell power generation system shown in FIG. 16 and the flowchart of the second example of the specific operation stop method shown in FIG. Another example of the operation of stopping the operation of the fuel cell power generation system will be described. When the purging with water vapor in the internal atmosphere of the fuel gas generation unit 15 and the purging with the desulfurization gas in the fuel gas flow path atmosphere including the fuel electrode 11a of the fuel cell 11 are completed, the desulfurization gas supply valve 29 is closed.

  Next, the on-off valves 31, 24 and 22 and the source gas supply valve 25 are opened. Further, the flow path switching valve 18 connects the flow path to the fuel cell bypass pipe 21. Thereafter, the blower 30 is operated, and air flows from the fuel gas generation unit 15 through the fuel cell bypass pipe 21 to the burner 15b, and further from the fuel gas generation unit bypass pipe 23 through the fuel electrode 11a of the fuel cell 11 to the burner 15b. This purges the atmosphere of the entire fuel gas passage with air.

  After the purge process is finished, the blower 30 is stopped and the on-off valve 31 is closed to finish the operation. In this purge step, the internal atmosphere of the fuel gas generation unit 15 and the atmosphere of the fuel gas flow path including the fuel electrode 11a of the fuel cell 11 are purged at the same time, so that the purge can be performed in a short time. That is, the configuration of the fuel cell power generation system shown in the present embodiment and the purge process of this specific example have the same effect as the fuel cell power generation system described in the beginning of the sixth embodiment, and the purge process using air can be completed in a short time. It also has the effect that it can be realized.

  By the way, the air flows into the reaction unit 15a or can flow into the reaction unit 15a of the fuel gas generation unit 15 of the fuel cell power generation system in Embodiments 4 and 6 in the course of purging with air. There is sex. Therefore, as shown in FIG. 19, the reaction unit 15a of the fuel gas generation unit 15 includes a shift unit 15d provided with a shift catalyst body including at least a noble metal and a metal oxide, and at least carbon monoxide in the shift unit. It is more effective to include a reformer 15c that is a hydrogen gas supply unit that supplies hydrogen gas containing water vapor as a subcomponent.

  That is, in FIG. 19, a raw material gas or a desulfurized gas is supplied to the reformer 15c, and a reforming reaction of the raw material gas or the desulfurized gas is caused at a high temperature where water vapor exists in the reformer 15c. Carbon monoxide as a by-product in the reforming reaction is reacted with water vapor in the next shift section 15d to generate hydrogen and carbon dioxide. The burner 15b has a role of increasing the temperature of the reformer 15c.

According to this configuration, since the shift catalyst body has oxygen poisoning resistance, even if air is allowed to flow into the reaction part 15a for the purge process, an effect of preventing performance deterioration due to air can be obtained.
In the first to sixth embodiments, examples in which city gas is used as purge gas or raw material gas have been described. Since city gas is maintained as a social infrastructure, it does not require cylinders like nitrogen. Therefore, from the viewpoint that a simpler configuration can be realized, the desulfurization gas from which the sulfur component is removed from the city gas has been described as a more effective purge gas.

  However, the same effect can be obtained by using a gas mainly composed of a compound containing at least carbon and hydrogen, such as a hydrocarbon containing no sulfur component, such as methane gas, as the purge gas. In this case, a desulfurizer is not required, and the same raw material for generating hydrogen in the purge gas can be used. Besides these city gas or methane gas, natural gas, propane gas, dimethyl ether gas, etc. can also be used as raw material gas or purge gas.

  The fuel cell power generation system of the present invention is suitably used for stationary stationary power generation for home use, power source for electric vehicles, and the like.

It is a figure which shows typically the structure of the fuel cell power generation system in Embodiment 1 of this invention. It is a figure which shows typically the structure of the fuel cell power generation system in Embodiment 2 of this invention. It is a flowchart which shows an example of the electromotive method of the fuel cell power generation system of Embodiment 2 of this invention. It is a flowchart which shows an example of the operation stop method of the fuel cell power generation system of Embodiment 2 of this invention. It is a flowchart which shows another example of the electromotive method of the fuel cell power generation system of Embodiment 2 of this invention. It is a figure which shows typically the structure of the fuel cell power generation system in Embodiment 3 of this invention. It is a flowchart which shows an example of the electromotive method of the fuel cell power generation system of Embodiment 3 of this invention. It is a flowchart which shows an example of the operation stop method of the fuel cell power generation system of Embodiment 3 of this invention. It is a flowchart which shows another example of the operation stop method of the fuel cell power generation system of Embodiment 3 of this invention. It is a flowchart which shows another example of the electromotive method of the fuel cell power generation system of Embodiment 3 of this invention. It is a figure which shows typically the structure of the fuel cell power generation system in Embodiment 4 of this invention. It is a flowchart which shows an example of the operation stop method of the fuel cell power generation system of Embodiment 4 of this invention. It is a figure which shows typically the structure of the fuel cell power generation system in Embodiment 5 of this invention. It is a flowchart which shows an example of the operation stop method of the fuel cell power generation system of Embodiment 5 of this invention. It is a flowchart which shows another example of the operation stop method of the fuel cell power generation system of Embodiment 5 of this invention. It is a figure which shows typically the structure of the fuel cell power generation system in Embodiment 6 of this invention. It is a flowchart which shows an example of the operation stop method of the fuel cell power generation system of Embodiment 6 of this invention. It is a flowchart which shows another example of the operation stop method of the fuel cell power generation system of Embodiment 6 of this invention. It is a figure which shows typically the structure of an example of the fuel gas production | generation part which can be used for each embodiment of this invention. It is a figure which shows typically the structure of the conventional fuel cell power generation system.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Fuel cell 11a Fuel electrode 15 Fuel gas production | generation part 15a Reaction part 15b Burner 13, 16 Desulfurizer 17, 26, 30 Blower 12 Desulfurization gas supply pipe 14, 22, 24, 27, 31 Open / close valve 18 Flow path switching valve 19 Fuel Gas supply pipe 20 Residual fuel gas pipe 21 Fuel cell bypass pipe 23 Fuel gas generator bypass pipe 25 Raw material gas supply valve 28 Steam generator 29 Desulfurization gas supply valve

Claims (25)

A fuel cell having a fuel electrode and an oxidant electrode, and a fuel gas generating means for generating a hydrogen-rich fuel gas from a raw material mainly comprising a compound containing carbon and hydrogen, and the fuel of the fuel cell including the fuel electrode A fuel gas supply means for supplying the fuel gas to the gas flow path; an oxidant gas supply means for supplying an oxidant gas to the oxidant gas flow path of the fuel cell including the oxidant electrode; and the fuel gas flow path. A replacement gas supply means for supplying the raw material as a replacement gas, and a water vapor supply means for supplying water vapor to the fuel gas generation means,
After the power generation of the fuel cell, the replacement gas supply means injects the raw material into the fuel gas flow path to replace the atmosphere of the fuel gas flow path with the raw material, and the fuel gas generation means generates fuel gas. The fuel cell power generation system is configured such that the water vapor is injected into the fuel gas generation means by the water vapor supply means, and the atmosphere inside the fuel gas generation means is replaced with the water vapor.   Air supply means for supplying air to the fuel gas flow path to replace the atmosphere of the fuel gas flow path with air, and after completion of power generation, the replacement gas supply means supplies the raw material to the fuel gas flow path. Injecting and replacing the atmosphere of the fuel gas flow path with the raw material, and then injecting the air into the fuel gas flow path by the air supply means to replace the atmosphere of the fuel gas flow path with the air. The fuel cell power generation system according to claim 1, wherein:   2. The fuel cell power generation system according to claim 1, wherein the fuel gas generation unit performs fuel gas generation until injection of the raw material into the fuel gas flow path by the replacement gas supply unit is completed.   After completion of power generation, the replacement gas supply means injects the raw material into the fuel gas flow path, replaces the atmosphere of the fuel gas flow path with the raw material, and then stops the fuel gas generation of the fuel gas generation means. 4. The fuel cell power generation system according to claim 3, wherein the water vapor is injected into the fuel gas generation means by the water vapor supply means to replace the atmosphere inside the fuel gas generation means with the water vapor.   After the power generation is completed, the fuel gas generation unit stops the fuel gas generation, and the water vapor supply unit injects the water vapor into the fuel gas generation unit to replace the atmosphere inside the fuel gas generation unit with the water vapor. 2. The fuel cell power generation system according to claim 1, wherein the raw material is injected into the fuel gas flow path by the replacement gas supply means to replace the atmosphere of the fuel gas flow path with the raw material.   Air supply means for supplying air to the fuel gas flow path and the fuel gas generation means to replace the atmosphere of the fuel gas flow path and the atmosphere inside the fuel gas generation means with the air; Injecting the raw material into the fuel gas flow path to replace the atmosphere of the fuel gas flow path with the raw material, and injecting the water vapor into the fuel gas generation means to change the atmosphere inside the fuel gas generation means to the After substituting with water vapor, the air is injected into both the fuel gas flow path and the fuel gas generation means by the air supply means, and the atmosphere of the fuel gas flow path and the atmosphere inside the fuel gas generation means The fuel cell power generation system according to claim 4, wherein the air is replaced with the air.   The fuel cell power generation system according to claim 6, wherein the air injection by the air supply means is performed in series from the fuel gas generation means to the fuel gas flow path.   The fuel cell power generation system according to claim 6, wherein the air injection by the air supply means is performed in parallel with the fuel gas generation means and the fuel gas flow path.   Hydrogen gas for supplying a hydrogen gas containing at least carbon monoxide and water vapor as subcomponents to the shift portion, wherein the fuel gas generating means is provided with a shift catalyst body having at least a noble metal and a metal oxide as constituent materials. The fuel cell power generation system according to claim 6, further comprising a supply unit.   The replacement gas supply means comprises bypass means for bypassing the fuel gas generation means and injecting the raw material into the fuel gas flow path, and after completion of power generation of the fuel cell, the bypass gas supply means passes through the bypass means. 2. The fuel cell power generation system according to claim 1, wherein the raw material is injected into a fuel gas flow path, and the atmosphere of the fuel gas flow path is replaced with the raw material.   Air supply means for supplying air to the fuel gas flow path and replacing the atmosphere of the fuel gas flow path with the air is further provided, and after the power generation is completed, the raw material is injected into the fuel gas flow path by the bypass means. Then, after replacing the atmosphere of the fuel gas flow path with the raw material, the air is injected into the fuel gas flow path by the air supply means, and the atmosphere of the fuel gas flow path is replaced with the air. The fuel cell power generation system according to claim 10, characterized in that:   11. The fuel cell power generation system according to claim 10, wherein the fuel gas generation means performs fuel gas generation until the injection of the raw material into the fuel gas flow path by the bypass means is completed.   After the power generation of the fuel cell is completed, the raw material is injected into the fuel gas flow path by the bypass means, and the atmosphere of the fuel gas flow path is replaced with the raw material, and then the fuel gas generation of the fuel gas generation means is stopped. 13. The fuel cell power generation system according to claim 12, wherein the water vapor is injected into the fuel gas generation means by the water vapor supply means to replace the atmosphere inside the fuel gas generation means with the water vapor. .   After the power generation of the fuel cell is completed, the fuel gas generation unit stops the fuel gas generation, and the water vapor supply unit injects the water vapor into the fuel gas generation unit, thereby changing the atmosphere inside the fuel gas generation unit. 11. The fuel cell power generation system according to claim 10, wherein the fuel gas power generation system is replaced with water vapor and the raw material is injected into the fuel gas flow path by the bypass means to replace the atmosphere of the fuel gas flow path with the raw material. .   Air supply means for supplying air to the fuel gas flow path and the fuel gas generation means to replace the atmosphere of the fuel gas flow path and the atmosphere inside the fuel gas generation means with the air; Injecting the raw material into the fuel gas flow path to replace the atmosphere of the fuel gas flow path with the raw material, and injecting the water vapor into the fuel gas generation means to change the atmosphere inside the fuel gas generation means to the After substituting with water vapor, the air is injected into both the fuel gas flow path and the fuel gas generation means by the air supply means, and the atmosphere of the fuel gas flow path and the atmosphere inside the fuel gas generation means The fuel cell power generation system according to claim 13 or 14, wherein the air is replaced with the air.   16. The fuel cell power generation system according to claim 15, wherein the air injection by the air supply means is performed in series from the fuel gas generation means to the fuel gas flow path.   16. The fuel cell power generation system according to claim 15, wherein the air injection by the air supply means is performed in parallel with the fuel gas generation means and the fuel gas flow path.   Hydrogen gas for supplying a hydrogen gas containing at least carbon monoxide and water vapor as subcomponents to the shift portion, wherein the fuel gas generating means is provided with a shift catalyst body having at least a noble metal and a metal oxide as constituent materials. The fuel cell power generation system according to claim 15, further comprising a supply unit.   19. The fuel cell power generation system according to claim 1, further comprising a desulfurizer that removes a sulfur component from the raw material, wherein the raw material that has passed through the desulfurizer is supplied as the replacement gas by the replacement gas supply unit.   A fuel cell having a fuel electrode and an oxidizer electrode; and a fuel gas generating means for generating a hydrogen-rich fuel gas from a raw material mainly composed of a compound containing carbon and hydrogen. An operation method of a fuel cell power generation system, comprising: a fuel gas supply means for supplying the fuel gas; and a water vapor supply means for supplying water vapor to the fuel gas generation means, wherein the fuel cell A first replacement step of stopping the fuel gas generation step by the gas generation means, injecting the raw material into the fuel gas flow channel as a replacement gas, and replacing the atmosphere of the fuel gas flow channel with the raw material; and the water vapor A third replacement step of supplying water vapor to the fuel gas generation means by a supply means and substituting the atmosphere inside the fuel gas generation means with the water vapor; Method of operating a fuel cell power generation system.   An air supply means for supplying air to the fuel gas flow path to replace the atmosphere of the fuel gas flow path with air; and after performing the first replacement step after power generation, the air supply means 21. The operating method of a fuel cell power generation system according to claim 20, further comprising a second replacement step of injecting air into the fuel gas flow path to replace the atmosphere of the fuel gas flow path with the air.   21. The operating method of a fuel cell power generation system according to claim 20, wherein the fuel gas is generated in the fuel gas generation means until the injection of the raw material into the fuel gas flow path in the first replacement step is completed.   21. The fuel according to claim 20, wherein the first replacement step is a step of bypassing the fuel gas generation means and supplying the raw material to the fuel gas flow channel to replace the atmosphere of the fuel gas flow channel with the raw material. Operation method of battery power generation system.   An air supply means for supplying air to the fuel gas flow path to replace the atmosphere of the fuel gas flow path with air; and after performing the first replacement step after power generation, the air supply means 24. The method of operating a fuel cell power generation system according to claim 23, further comprising a second replacement step of injecting air into the fuel gas flow path to replace the atmosphere of the fuel gas flow path with the air.   24. The operation method of a fuel cell power generation system according to claim 23, wherein the fuel gas is generated in the fuel gas generation means until the injection of the raw material into the fuel gas flow path in the first replacement step is completed.

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