JP2023121039A - Fuel cell system and method of operating the same - Google Patents

Abstract

To suppress water adsorption of a desulfurization agent that desulfurizes a material gas supplied to a fuel cell.SOLUTION: A fuel cell system 10 comprises: an FC (fuel cell) stack 42 that generates power with a fuel gas supplied to an anode 42A and air supplied to a cathode 42B; a desulfurizer 12 provided at an upstream side from the anode 42A to remove a sulfur component from gas supplied from a gas piping 41; a dew point meter 11 provided at an upstream side from the desulfurizer 12 to measure a dew point of gas flowing through the gas piping 41; and a gas supply control unit 48 that stops gas supply from piping 4 to the desulfurizer 12 when the dew point measured by the dew point meter 11 becomes larger than a threshold TH1.SELECTED DRAWING: Figure 3

Description

The present invention relates to a fuel cell system and a method of operating this fuel cell system.

A desulfurization agent that adsorbs sulfur from the source gas is mounted in a gas path of the fuel cell system that receives the source gas to which sulfur is added. By removing the sulfur content from the source gas, sulfur poisoning of the reforming catalyst is suppressed, and normal operation of the fuel cell system is maintained.

In Patent Document 1, based on the dew point of the raw material gas and the cumulative flow rate of the raw material gas flowing through the raw material gas passage from the reference time, information regarding maintenance of the first desulfurizer and the second desulfurizer is reported, thereby desulfurizing. Promoting maintenance (replacement) of equipment.

JP 2012-169044 A

By the way, this desulfurization agent has the characteristic that when supplied with a gas containing relatively large amounts of water, it adsorbs water rather than sulfur and desorbs the adsorbed sulfur.

Therefore, when water flows into the gas pipe on the upstream side of the gas supply area due to some force majeure such as gas construction, the water-containing gas is supplied to the fuel cell system, and the water adsorbs the sulfur adsorbed by the desulfurization agent. It is conceivable that sulfur poisoning of the reforming catalyst, the fuel cell stack, etc. will affect the normal operation of the fuel cell system.

Patent Literature 1 does not assume the case where the sulfur content adsorbed on the desulfurization agent is released, and cannot deal with it. On the other hand, there is a problem of how to deal with the case where the gas temporarily containing water no longer contains water.

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above facts, and an object of the present invention is to suppress the desorption of sulfur due to water adsorption of a desulfurizing agent that desulfurizes a raw material gas supplied to a fuel cell.

A fuel cell system according to claim 1 comprises: a fuel cell that generates electricity by fuel gas supplied to a fuel electrode and air supplied to an air electrode; A desulfurizer that removes sulfur components from gas, a dew point meter that is provided upstream of the desulfurizer and that measures the dew point of the gas flowing through the gas pipe, and the dew point measured by the dew point meter equals the water contamination value. and a gas supply control unit that stops the gas supply from the gas pipe to the desulfurizer when the gas exceeds the limit.

In the fuel cell system according to claim 1, when the dew point measured by the dew point meter exceeds the water contamination value, the gas supply control section stops the gas supply from the gas pipe to the desulfurizer. Therefore, the water-containing gas does not flow into the desulfurizer, and the desorption of sulfur due to the adsorption of water to the desulfurizing agent can be suppressed.

In the fuel cell system according to claim 2, the gas supply control unit stops the gas supply from the gas pipe to the desulfurizer, and then removes water from the gas supplied to the gas pipe. When it is determined that the mixing is eliminated, the gas supply from the gas pipe to the desulfurizer is restarted.

According to the fuel cell system of claim 2, after the gas supply from the gas pipe to the desulfurizer is stopped, the gas supply control unit determines that the gas supplied to the gas pipe has no longer mixed with water. In this case, gas supply from the gas pipe to the desulfurizer is resumed. Therefore, the fuel cell system can be properly operated.

In the fuel cell system according to claim 3, the gas supply control unit controls the supply of gas from the gas pipe to the dew point meter at a preset normal confirmation time after gas supply from the gas pipe to the desulfurizer is stopped. When the gas is supplied and the dew point measured by the dew point meter falls within the normal range, it is determined that the water contamination has been eliminated.

Thus, when the dew point measured by the dew point meter falls within the normal range, it can be determined that the water contamination is eliminated.

In the fuel cell system according to claim 4, the gas supply control unit determines that the water contamination is eliminated when receiving a notification that the water contamination is eliminated via the network.

In this manner, when a notification indicating that the water contamination is eliminated is received via the network, it can be determined that the water contamination is eliminated.

The fuel cell system according to claim 5 has a purge flow path branched from the gas pipe at a branching part upstream of the desulfurizer, and the gas supply control unit connects the gas pipe to the desulfurizer. After the gas supply is stopped, when it is determined that the water contamination is eliminated in the gas supplied to the gas pipe and the water contamination is eliminated, the gas supply from the gas pipe to the desulfurizer is restarted. Before, the gas in the gas line is switched to supply to the purge flow path to purge the gas in the gas line.

In the fuel cell system according to claim 5, before resuming the gas supply from the gas pipe to the desulfurizer, the gas in the gas pipe is switched to the purge passage to purge the gas in the gas pipe. Therefore, it is possible to prevent the gas mixed with water from being supplied to the desulfurizer.

In the fuel cell system according to claim 6, the dew point meter is provided upstream of the branching section, and the gas supply control section controls the desulfurizer after gas supply from the gas pipe to the desulfurizer is stopped. Gas is supplied from the gas pipe to the dew point meter at each normal confirmation time set in advance, and gas is supplied from the gas pipe to the purge flow path via the dew point meter during the normal confirmation time.

According to the fuel cell system according to claim 6, after the gas supply from the gas pipe to the desulfurizer is stopped, the gas supply from the gas pipe to the dew point meter is executed at the preset normal confirmation time, and the normal range is reached. It is possible to avoid supplying gas to the desulfurizer when determining whether or not.

A fuel cell system according to claim 7 comprises a reformer for reforming the gas supplied from the gas pipe and a combustor for raising the temperature of the reformer, and the purge passage is connected to the combustor. It is

According to the fuel cell system of claim 7, the water-containing gas can be used for combustion in the combustor that raises the temperature of the reformer.

In the fuel cell system according to claim 8, the purge passage is connected to the combustor of the heat source equipment.

According to the fuel cell system of claim 8, the water-containing gas can be used for combustion in the combustor of the heat source equipment.

A fuel cell system operating method according to claim 9 operates a fuel cell system in which gas is supplied via a desulfurizer to a fuel cell that generates electricity by fuel gas supplied to a fuel electrode and air supplied to an air electrode. In the fuel cell system operating method, the gas supply from the gas pipe to the desulfurizer is stopped when the dew point of the gas flowing through the gas pipe on the upstream side of the desulfurizer exceeds the water contamination value. .

In the fuel cell system operating method according to claim 9, when the dew point of the gas flowing through the gas pipe on the upstream side of the desulfurizer exceeds the water contamination value, gas supply from the gas pipe to the desulfurizer is stopped. Therefore, the water-containing gas does not flow into the desulfurizer, and the desorption of sulfur due to water adsorption of the desulfurizing agent can be suppressed.

In the fuel cell system operating method according to claim 10, the water contamination elimination state is established in which contamination of the gas supplied to the gas pipeline is eliminated after the gas supply from the gas pipeline to the desulfurizer is stopped. When it is determined that, the gas supply from the gas pipe to the desulfurizer is restarted.

According to the method for operating a fuel cell system according to claim 10, when it is determined that water is no longer mixed in the gas supplied to the gas pipe after stopping the gas supply from the gas pipe to the desulfurizer, the gas The gas supply from the piping to the desulfurizer is resumed. Therefore, the fuel cell system can be properly operated.

In the method for operating a fuel cell system according to claim 11, the water contamination elimination state is achieved in which contamination of the gas supplied to the gas pipeline is eliminated after the gas supply from the gas pipeline to the desulfurizer is stopped. When it is determined that, before resuming the gas supply from the gas pipe to the desulfurizer, the gas in the gas pipe is purged to a portion different from the desulfurizer.

According to the fuel cell system operating method of claim 11, the gas in the gas pipe is purged to a portion different from the desulfurizer before gas supply from the gas pipe to the desulfurizer is resumed. Therefore, it is possible to prevent the gas mixed with water from being supplied to the desulfurizer.

According to the fuel cell system and the method of operating the fuel cell system according to the present invention, it is possible to suppress desorption of sulfur due to water adsorption of the desulfurizing agent that desulfurizes the raw material gas supplied to the fuel cell.

1 is an overall view of a fuel cell operation management system according to a first embodiment; FIG. It is an example of area information corresponding to each gas pipe. 1 is a configuration diagram of a fuel cell system according to a first embodiment; FIG. 1 is a configuration diagram of a fuel cell operation management device according to a first embodiment; FIG. 4 is a flowchart of dew point corresponding operation processing according to the first embodiment. 4 is a flow chart of water condition confirmation processing according to the first embodiment. 4 is a flowchart of purge processing according to the first embodiment; FIG. 2 is a configuration diagram of a fuel cell system according to a second embodiment; FIG. 10 is a flowchart of water condition confirmation processing according to the second embodiment; 9 is a flowchart of purge processing according to the second embodiment;

<First Embodiment>
A first embodiment of the present invention will be described with reference to the drawings.

(Overall Configuration of Fuel Cell Operation Management System S)
FIG. 1 is a schematic configuration diagram of a fuel cell operation management system S that operates and manages a fuel cell system 10 according to this embodiment. The fuel cell operation management system S shown in FIG. 1 is an operation management system for a plurality of fuel cell systems 10 installed at various locations, and includes a fuel cell operation management device 20 and the fuel cell systems 10 installed at various locations. ing.

The fuel cell operation management device 20 collects water contamination information and water contamination gas pipe position information from each fuel cell system 10, and issues a stop instruction, a stop cancellation instruction, etc. to the fuel cell system 10 affected by the water contamination. It is a sending device. The fuel cell operation management device 20 and the fuel cell system 10 are connected to a network N and can communicate with each other. Network N is, for example, the Internet.

The fuel cell system 10 is, for example, ENE-FARM (registered trademark). The fuel cell system 10 is installed in a user's home, an apartment complex, a factory, or the like. In each fuel cell system 10, as shown in FIG. 2, area information J corresponding to gas pipes 28A, 28B, 28C, . For example, "area information JA" is registered for the fuel cell system 10 installed in the area receiving gas supply from the gas conduit 28A, and the fuel cell system 10 installed in the area receiving gas supply from the gas conduit 28B. "area information JB" is registered. A fuel cell system 10 is connected to a network N. Details of the fuel cell system 10 will be described later.

Town gas to which a sulfur component is added flows through the gas pipe 28 . In this embodiment, city gas will be described as an example, but the present invention can also be applied to other gas pipes through which gases containing hydrocarbon components flow.

(Configuration of fuel cell system 10)
As shown in FIG. 3, the fuel cell system 10 includes a dew point meter 11, a desulfurizer 12, a reformer 40, a fuel cell stack 42 (hereinafter referred to as "FC stack 42"), a burner 44, an FC controller 45. , an operation panel 52 and a communication device 54 . The fuel cell system 10 is supplied with a gas pipe 41 from a gas pipe 28 through a pressure regulator (not shown) to reduce the pressure of the raw material gas.

A dew point meter 11, a desulfurizer 12, a reformer 40, and an FC stack 42 are connected to the gas pipe 41 from the upstream side. A dew point meter 11 measures the dew point of the source gas. The desulfurizer 12 is filled with a desulfurizing agent, and the desulfurizing agent adsorbs and removes the sulfur component added to the source gas. Thereby, sulfur poisoning in the reformer 40 and the FC stack 42 can be suppressed.

A solenoid valve V<b>1 is provided upstream of the dew point meter 11 . The opening and closing of the electromagnetic valve V1 controls the supply and stoppage of the raw material gas from the gas pipe 41 .

A blower B<b>1 is provided downstream of the dew point meter 11 and upstream of the desulfurizer 12 . The blower B<b>1 sends the material gas downstream in accordance with the amount of power generated by the fuel cell system 10 .

A reformer 40 is provided downstream of the desulfurizer 12 . The reformer 40 contains a reforming catalyst and reforms the raw material gas into a fuel gas containing hydrogen.

The FC stack 42 has a plurality of stacked fuel cells. Various fuel cells such as a solid oxide fuel cell (SOFC), a molten carbonate fuel cell (MCFC), a polymer electrolyte fuel cell (PEFC), etc. can be applied as fuel cells constituting the FC stack 42. can be done. Each fuel cell of the FC stack 42 has an electrolyte membrane, and an anode (fuel electrode) 42A and a cathode (air electrode) 42B laminated on the front and back surfaces of the electrolyte membrane, respectively. The fuel gas from reformer 40 is supplied to anode 42A. Air is supplied from an air blower (not shown) to the cathode 42B. Power generation reactions at the anode 42A and the cathode 42B generate power in the FC stack 42, and the power is output to a circuit (not shown).

The burner 44 is provided downstream of the FC stack 42 and is supplied with anode off-gas discharged from the anode 42A and cathode off-gas discharged from the cathode 42B. The burner 44 burns combustible components in the anode offgas with oxygen in the cathode offgas. Combustion heat in the burner 44 can be used to heat the reformer 40 .

A purge flow path 50 is branched from the gas pipe 41 downstream of the blower B<b>1 and upstream of the desulfurizer 12 . The purge passage 50 is provided with an electromagnetic valve V2. The purge channel 50 is connected with the burner 44 . By opening and closing the solenoid valves V1 and V2, the source gas supply destination from the gas pipe 41 is switched to either the desulfurizer 12 side or the burner 44 side.

The FC control unit 45 is a computer that controls each part of the fuel cell system 10, and is connected to the dew point meter 11, the solenoid valves V1 and V2, the blower B1, and other parts (not shown) of the fuel cell system 10. there is

The FC control unit 45 has a processor 46 and a memory 47 as hardware. The processor 46 has a CPU (Central Processing Unit) and the like. The memory 47 has ROM (Read Only Memory), RAM (Random Access Memory), storage, and the like.

The ROM stores various programs and various data. RAM temporarily stores programs or data as a work area. The storage is configured by a HDD (Hard Disk Drive), SSD (Solid State Drive), or the like, and stores various programs including an operating system and various data. A program for controlling the fuel cell system 10 is stored in the ROM or storage. The processor 46 reads the program 47A and executes the program 47A using the RAM as a work area.

In the storage area 47B of the memory 47, the area information J of the fuel cell system 10, the threshold value TH1 as a water mixture value for suspecting abnormal water mixture, the threshold TH2 for confirming that the abnormal water mixture has been eliminated, etc. is stored, the operating data output from each part in the fuel cell system 10, the dew point data output from the dew point meter 11, and the like are stored.

Here, the threshold value TH1 at which abnormal water contamination is suspected is set to a numerical value at which the dew point in the gas flowing through the gas pipe 41 becomes high and abnormal water contamination is suspected. Further, the threshold TH2 for confirming the elimination of abnormal water intrusion is a numerical value for confirming that the dew point that has once become abnormally high has returned to normal, and is set lower than the threshold TH1.

The processor 46 has a gas supply controller 48 as a functional configuration. The function of the gas supply control unit 48 is realized by the processor 46 executing the program 47A.

The operation panel 52 has indicators, lamps, switches, and the like. The operation panel 52 has switches for changing the operation and settings of the fuel cell system 10 . Communicator 54 is, for example, a modem. The communication device 54 has a function of connecting the fuel cell operation management device 20 and the FC control unit 45 through the network N so as to be able to communicate with each other.

The dew point meter 11 outputs the measured dew point value to the FC control unit 45 as dew point data. When the concentration of water vapor in the raw material gas increases and the numerical value of the dew point data becomes equal to or higher than the threshold value TH1 for suspecting abnormal water contamination, the FC control unit 45 outputs the area of the fuel cell system 10 as the water contamination information. Together with the information J, it is transmitted to the fuel cell operation management device 20 via the network N.

(Configuration of fuel cell operation management device 20)
The fuel cell operation management device 20 includes an input device 22 and a computer 23, as shown in FIG. The input device 22 is, for example, a keyboard, a touch panel, or the like. The computer 23 includes a processor 24, a memory 25, a database 26, and a communication interface 27 as hardware. The basic configurations of the processor 24 and memory 25 are the same as the processor 46 and memory 47 (see FIG. 2) of the FC control unit 45 described above.

The memory 25 stores a program 28P for managing the operation of the fuel cell system 10 installed within the management target area. In the database 26, information (including area information J) regarding the fuel cell system 10 within the managed area is stored in advance.

The communication interface 27 has a function of connecting the fuel cell system 10 and the computer 23 through the network N so as to be able to communicate with each other.

The computer 23 includes a water contamination information collection unit 24A, a fuel cell identification unit 24B, and a shutdown instruction transmission unit 24C as functional components. These functional units are implemented by the processor 24 executing the program 28 .

The water-mixed information collection unit 24A has a function of correlating the water-mixed gas pipe 28 with the positional information of the water-mixed gas pipe 28W and storing them in the database 26 . The water contamination information and the location information of the water contamination gas pipe 28W include information obtained from inquiries from users and information from suppliers.

If the information source is an inquiry from a user or a contact from a supplier, the operator inputs the water-mixed information and the positional information of the water-mixed gas pipe 28W from the input device 22 . In the case of an inquiry from a user, the water-containing gas conduit 28W uses the area information J where the user is located as position information. In the case of communication from a business, the information according to the content of the communication is used as the location information. For example, when water is mixed in a gas pipe during gas work, the ID information of the gas pipe 28 affected by the gas work is used as position information.

The fuel cell identification unit 24B has a function of identifying the fuel cell system 10 supplied with the gas from the water-mixed gas conduit 28W. The shutdown instruction transmission unit 24C has a function of transmitting a shutdown instruction to the fuel cell system 10 identified by the fuel cell identification unit 24B.

Next, the operation of the fuel cell system 10 of this embodiment will be described.

During the power generation operation of the fuel cell system 10, the solenoid valve V1 is opened and the solenoid valve V2 is closed. The city gas supplied from the gas pipe 28 to the gas pipe 41 is sent to the desulfurizer 12 by the blower B1, and the desulfurizer 12 removes sulfur components from the city gas. The city gas desulfurized by the desulfurizer 12 is reformed by the reformer 40 to generate fuel gas containing hydrogen. The fuel gas is supplied to the anode 42A of the FC stack 42 and causes a power generation reaction with the air supplied to the cathode 42B to obtain electric power, which is extracted from a line (not shown). Offgases from the anode 42A and the cathode 42B are delivered to the burner 44 and burned.

During the power generation operation of the fuel cell system 10, the dew point meter 11 measures the dew point of the gas pipe 41 and outputs the measurement result to the FC control unit 45 as dew point data. The FC control unit 45 stores the received dew point data in the storage area 47B of the memory 47 together with the input date and time. 5 is read from the memory 47 and executed by the processor 46. FIG.

First, in step S10, the latest dew point data is read from the storage area 47B, and in step S11, it is determined whether the dew point data is equal to or greater than the threshold value TH1. If the dew point data is less than the threshold TH1, the process returns to step S10.

If the dew point data is equal to or greater than the threshold TH1, the water contamination information is transmitted to the fuel cell operation management device 20 together with the area information J of the fuel cell system 10 in step S12. As a result, the water contamination information and the area information J are registered in the fuel cell operation management device 20 .

Next, in step S13, the solenoid valve V1 is closed, and in step S14, power generation by the fuel cell system 10 is stopped. As a result, the supply of gas mixed with water is stopped, and adsorption of water to the desulfurizing agent in the desulfurizer 12 can be suppressed.

Next, in step S20, a water condition confirmation process is executed. In the water condition confirmation process, as shown in FIG. 6, first, in step S21, it is determined whether or not water contamination elimination information has been received. The water contamination elimination information is information transmitted from the fuel cell operation management device 20. When the fuel cell operation management device 20 receives the water contamination elimination information together with the area information J, the water contamination elimination information is transmitted. , is information to be transmitted to the fuel cell system 10 installed in the area of the corresponding area information J. In step S21, if the water contamination elimination information has been received, the water status confirmation process is terminated.

If the water contamination elimination information has not been received, it is determined in step S22 whether or not the normality confirmation time T has elapsed. The normality confirmation time T is a time interval for checking the state of water contamination after power generation by the fuel cell system 10 is stopped in step S14, and is set in advance to, for example, 30 minutes or 1 hour. The normality confirmation time T may be a constant time, or may be shortened as the number of determinations is repeated. For example, it can be set to 1 hour for the 1st to 3rd flow, 30 minutes for the 4th to 6th flow, 10 for the 7th and subsequent flows, and the like. If the normality confirmation time T has not elapsed, the process returns to step S21.

When the normality confirmation time T has passed, the electromagnetic valve V2 is opened in step S23. As a result, the city gas flows from the gas pipe 41 to the purge passage 50, and the dew point of the flowing city gas is measured by the dew point meter 11 and stored in the storage area 47B. At step S24, the latest dew point data is read from the storage area 47B, and at step S25, the electromagnetic valve V2 is closed. Since the electromagnetic valve V2 is temporarily opened to collect the dew point data and then closed in a short time, the amount of town gas supplied to the purge flow path 50 is small.

In step S26, it is determined whether the dew point data is equal to or less than the threshold TH2. If the determination is negative, the process returns to step S21. If the determination is affirmative, it can be determined that the dew point is normal and the water contamination has been eliminated. End the confirmation process. Upon receiving the water contamination elimination information, the fuel cell operation management device 20 transmits the water contamination elimination information together with the area information J to the fuel cell system 10 installed in the area of the area information J concerned.

Next, the purge process of step S30 (FIG. 5) is executed. In the purge process, as shown in FIG. 7, the solenoid valve V2 is opened in step S32. As a result, the city gas possibly mixed with water flows from the gas pipe 41 to the purge passage 50 . In step S34, it waits until the purge time elapses. The purge time is the time required for replacing the city gas, which may be contaminated with water, with city gas without water in the gas pipe 41, and is set in advance.

After it is determined in step S34 that the purge time has elapsed, the solenoid valve V2 is closed in step S36 to end the purge process. By this purging process, the water-mixed gas remaining upstream of the branched portion in the gas pipe 41 can be discharged.

Next, in step S15 (FIG. 5), the solenoid valve V1 is opened, and in step S16, power generation by the fuel cell system 10 is resumed, and the dew point operation process ends.

In the fuel cell system 10 of the present embodiment, gas supply to the desulfurizer 12 is stopped when the dew point data from the dew point meter 11 is equal to or greater than the threshold TH1 at which abnormal water contamination is suspected. As a result, the water-containing gas is prevented from flowing into the desulfurizer 12, and the adsorption of water by the desulfurizing agent can be suppressed. In addition, the adsorption of water by the desulfurizing agent and the discharge of sulfur components are also suppressed.

Further, after stopping the gas supply to the desulfurizer 12 and stopping the power generation in the fuel cell system 10, a small amount of gas is allowed to flow into the purge passage every normal confirmation time T, and the dew point is measured by the dew point meter 11. Therefore, it is possible to monitor the state of water contamination after stopping. When the measured dew point becomes equal to or lower than the threshold TH2 for confirming that the abnormal water contamination has been eliminated, it is determined that the normal state has been restored and the abnormal water contamination has been eliminated, and the fuel cell system 10 is automatically operated. Power generation operation can be resumed.

Further, before restarting the power generation operation of the fuel cell system 10, the gas in the gas pipe 41 is purged to the purge passage 50 and sent to the burner 44, so that the gas mixed with water is prevented from flowing into the desulfurizer 12. can be suppressed.

Although the purge channel 50 is provided in this embodiment, the purge channel 50 may not be provided. If the purge flow path 50 is not provided, the solenoid valve V1 is opened in step S23 and closed in step S25 in the water condition confirmation process of step S20. Also, the purge process in step S30 is not executed. Even in such a case, since a small amount of water-containing gas is sent to the desulfurizer 12, the release of sulfur components from the desulfurizing agent in the desulfurizer 12 can be suppressed.

<Second embodiment>
Next, a second embodiment of the invention will be described. In this embodiment, the same reference numerals are assigned to the same parts as in the first embodiment, and detailed description thereof will be omitted.

The fuel cell system 70 of this embodiment includes an external purge channel 51 in place of the purge channel 50 of the fuel cell system 10 of the first embodiment. The configuration other than the external purge channel 51 is the same as that of the fuel cell system 10 of the first embodiment.

As shown in FIG. 8, the fuel cell system 70 has an external purge channel 51 . The external purge flow path 51 is branched and connected downstream of the blower B<b>1 and upstream of the desulfurizer 12 . The external purge flow path 51 is provided with an electromagnetic valve V3. The solenoid valve V3 is connected to the FC control unit 45 and its opening and closing is controlled.

A downstream end of the external purge flow path 51 is connected to a burner 60A inside the heat source device 60 . The heat source device 60 is a device, such as a gas water heater and floor heating equipment, which uses combustion heat of a burner 60A as a heat source for heat exchange with water. By opening and closing the solenoid valves V1 and V3, the gas supply destination from the gas pipe 41 is switched to either the desulfurizer 12 side or the burner 44 side.

Next, the operation of the fuel cell system 70 of this embodiment will be described.

During the power generation operation of the fuel cell system 70, the solenoid valve V1 is opened and the solenoid valve V3 is closed.

During the power generation operation of the fuel cell system 70, the dew point meter 11 measures the dew point of the gas pipe 41 and outputs the measurement result to the FC control unit 45 as dew point data. The FC control unit 45 stores the received dew point data in the storage area 47B of the memory 47 together with the input date and time. 5 is read from the memory 47 and executed by the processor 46. FIG. In the dew point operation process, the water condition confirmation process is performed according to the flow shown in FIG.

First, in step S21, it is determined whether or not water contamination elimination information has been received. If the water contamination elimination information has been received, the water status confirmation process is terminated. If the water contamination elimination information has not been received, it is determined in step S22 whether or not the normality confirmation time T has elapsed. If the normality confirmation time T has not passed, the process returns to step S21.

When the normality confirmation time T has passed, the electromagnetic valve V3 is opened in step S28. As a result, city gas flows from the gas pipe 41 to the external purge passage 51, and the dew point of the flowing city gas is measured by the dew point meter 11 and stored in the storage area 47B. At step S24, the latest dew point data is read from the storage area 47B, and at step S29, the electromagnetic valve V3 is closed. Since the electromagnetic valve V3 is temporarily opened to collect dew point data and then closed in a short time, the amount of city gas supplied to the external purge flow path 51 is small.

In step S26, it is determined whether the dew point data is equal to or less than the threshold TH2. If the determination is negative, the process returns to step S21. If the determination is affirmative, the dew point is equal to or lower than the threshold TH2, and it can be determined that the water contamination has been eliminated. End the water status confirmation process.

Next, the purge process of step S30 (FIG. 5) is executed. In the purge process, as shown in FIG. 10, the electromagnetic valve V3 is opened in step S33. As a result, the city gas, which may be mixed with water, flows from the gas pipe 41 to the external purge channel 51 . In step S35, it waits until the purge time elapses. The purge time is the time required for replacing the city gas, which may be contaminated with water, with city gas without water in the gas pipe 41, and is set in advance.

After it is determined in step S34 that the purge time has elapsed, the solenoid valve V3 is closed in step S35 to end the purge process. By this purging process, the water-mixed gas remaining upstream of the branched portion in the gas pipe 41 can be discharged.

Thereafter, in step S15 (FIG. 5), the solenoid valve V1 is opened, and in step S16, power generation by the fuel cell system 10 is resumed, and the dew point corresponding operation process ends.

In the fuel cell system 70 of the present embodiment as well, the gas supply to the desulfurizer 12 is stopped when the dew point data from the dew point meter 11 is equal to or higher than the threshold TH1 at which abnormal water contamination is suspected. As a result, the water-containing gas is prevented from flowing into the desulfurizer 12, and adsorption of water to the desulfurizing agent can be suppressed. In addition, the adsorption of water by the desulfurizing agent and the discharge of sulfur components are also suppressed.

Further, after stopping the gas supply to the desulfurizer 12 and stopping the power generation in the fuel cell system 10, a small amount of gas is allowed to flow into the purge passage every normal confirmation time T, and the dew point is measured by the dew point meter 11. Therefore, it is possible to monitor the state of water contamination after stopping. When the measured dew point becomes equal to or lower than the threshold value TH2 for confirming that the abnormal water contamination has been eliminated, it is determined that the normal state has been restored and the abnormal water contamination has been eliminated, and the fuel cell system 10 is automatically operated. Power generation operation can be resumed.

Further, before restarting the power generation operation of the fuel cell system 10, the gas in the gas pipe 41 is purged to the external purge passage 51 and sent to the burner 44, so that the gas mixed with water does not flow into the desulfurizer 12. can be suppressed.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above, and it goes without saying that it is possible to carry out various modifications without departing from the spirit of the present invention. be.

10, 70 fuel cell system 11 dew point meter 12 desulfurizer 40 reformer 41 gas pipe 42 fuel cell stack (fuel cell)
42A anode (fuel electrode)
42B cathode (air electrode)
44 burner (combustor)
45 FC control unit (gas supply control unit)
48 gas supply control unit 50 purge channel 51 external purge channel (purge channel)
60 heat source machine 60A burner (combustor)
T normality confirmation time TH1 threshold (water contamination value)
TH2 threshold (normal range)
V1, V2, V3 Solenoid valve (gas supply controller)

Claims (11)

a fuel cell that generates electricity by fuel gas supplied to the fuel electrode and air supplied to the air electrode;
a desulfurizer provided upstream of the fuel electrode for removing sulfur components from gas supplied from a gas pipe;
a dew point meter provided upstream of the desulfurizer for measuring the dew point of the gas flowing through the gas pipe;
a gas supply control unit that stops gas supply from the gas pipe to the desulfurizer when the dew point measured by the dew point meter exceeds the water contamination value;
A fuel cell system with When the gas supply control unit determines that the water contamination is eliminated in the gas supplied to the gas pipeline after stopping the gas supply from the gas pipeline to the desulfurizer. , resuming gas supply from the gas pipe to the desulfurizer;
The fuel cell system according to claim 1. The gas supply control unit executes gas supply from the gas pipe to the dew point meter at each predetermined normal confirmation time after the gas supply from the gas pipe to the desulfurizer is stopped, and When the dew point measured by falls to the normal range, it is determined that the water contamination is eliminated.
3. The fuel cell system according to claim 2. The gas supply control unit determines that the water contamination is eliminated when a notification indicating that the water contamination is eliminated is received via the network.
3. The fuel cell system according to claim 2. having a purge flow path branched at a branch portion from the gas pipe heading for the desulfurizer on the upstream side of the desulfurizer;
When the gas supply control unit determines that the water contamination is eliminated in the gas supplied to the gas pipeline after stopping the gas supply from the gas pipeline to the desulfurizer. , before resuming gas supply from the gas pipe to the desulfurizer, the gas in the gas pipe is switched to supply to the purge passage to purge the gas in the gas pipe;
The fuel cell system according to any one of claims 2-4. The dew point meter is provided upstream of the branch,
After the gas supply from the gas pipe to the desulfurizer is stopped, the gas supply control unit executes the gas supply from the gas pipe to the dew point meter at each preset normal confirmation time to perform the normal confirmation. supplying gas from the gas pipe to the purge channel through the dew point meter at the same time;
The fuel cell system according to claim 5. A reformer for reforming the gas supplied from the gas pipe and a combustor for raising the temperature of the reformer,
the purge flow path is connected to the combustor;
7. The fuel cell system according to claim 5 or 6. The purge flow path is connected to the combustor of the heat source machine,
7. The fuel cell system according to claim 5 or 6. A fuel cell system operation method for operating a fuel cell system in which gas is supplied via a desulfurizer to a fuel cell that generates power by fuel gas supplied to a fuel electrode and air supplied to an air electrode, comprising:
when the dew point of the gas flowing through the gas pipe on the upstream side of the desulfurizer exceeds the water contamination value, gas supply from the gas pipe to the desulfurizer is stopped;
A method of operating a fuel cell system. After stopping the gas supply from the gas pipe to the desulfurizer, when it is determined that the water contamination is eliminated in the gas supplied to the gas pipe, the desulfurization is performed from the gas pipe. restart the gas supply to the vessel,
10. The fuel cell system operating method according to claim 9. After stopping the gas supply from the gas pipe to the desulfurizer, when it is determined that the water contamination is eliminated in the gas supplied to the gas pipe, the desulfurization is performed from the gas pipe. purging the gas in the gas pipe to a portion different from the desulfurizer before resuming gas supply to the device;
11. The fuel cell system operating method according to claim 10.