JP2010160969A - Fuel cell power generation system, and inspection method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable to easily confirm double shutoff of raw fuel of a fuel cell. <P>SOLUTION: In case, with the use of a first shutoff valve 16 and a second shutoff valve 17 provided at a raw-fuel gas supply piping 19 for supplying raw fuel gas to a reformer 12, and a control unit 15 capable of switching a downstream-side shutoff valve 24 provided at an anode offgas piping 20 connected to a downstream side of a fuel flow channel of a fuel cell body 11, a detection value of a pressure sensor 18 increases with time when the first fuel shutoff valve 16 and the downstream-side shutoff valve 24 are closed while the second fuel shutoff valve 17 is opened, sheet leak is determined to occur at the first fuel shutoff valve 16, and in case a detection value of the pressure sensor 18 increases with time when the second fuel shutoff valve 17 and the downstream-side shutoff valve 24 are closed while the first shutoff valve 16 is opened, sheet leak is determined to occur at the second fuel shutoff valve 17. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a fuel cell power generation system and an inspection method thereof.

  In a fuel cell power generation system, electric energy is generated by an electrochemical reaction between a fuel gas and an oxidant gas such as air. This system includes a reformer and a control device in addition to the fuel cell main body. The reformer generates hydrogen-rich reformed gas from raw fuel gas containing hydrocarbons. The fuel cell body generates power using the reformed gas generated by the reformer as fuel gas. A fuel cutoff valve is provided in a raw fuel system that supplies raw fuel to the reformer.

  In order to cut off the raw fuel in the raw fuel system, a double cut-off is required from the viewpoint of safety (see Non-Patent Document 1). For this reason, generally, two fuel cutoff valves are provided in series in the raw fuel system. In order to confirm double shutoff of raw fuel, it is necessary to check the soundness of the fuel shutoff valve during periodic inspections.

Japan Electrical Industry Standards JIS C 8822, “Safety Standards for Small Solid Polymer Fuel Cell Systems”, 2008

  However, if a seat leak occurs in one of the two fuel shut-off valves, the fuel is shut off by the other fuel shut-off valve that does not generate the seat leak. It is difficult to confirm double blockage. Therefore, it is necessary to check the soundness of the fuel shut-off valve through periodic inspections. For this reason, not only an extra maintenance cost is required, but it is difficult to check the soundness at a high frequency.

  Therefore, an object of the present invention is to make it possible to easily confirm double blocking of raw fuel in a raw fuel system of a fuel cell power generation system.

  In order to achieve the above-described object, the present invention provides a fuel cell power generation system that includes a reformer that generates a hydrogen-rich reformed gas from a raw fuel gas containing hydrocarbons, and a raw fuel gas that is supplied to the reformer. A raw fuel gas supply pipe to be supplied, a first fuel cutoff valve provided in the raw fuel gas supply pipe, and a second fuel provided downstream of the first fuel cutoff valve in the raw fuel gas supply pipe A shut-off valve, a pressure sensor provided on the downstream side of the second fuel shut-off valve of the raw fuel gas supply pipe, an anode formed with a fuel flow path, and a cathode formed with an oxidant flow path Provided in the fuel cell main body, a reformed gas supply pipe connecting the reformer and the fuel flow path, an anode exhaust gas pipe connected to the downstream end of the fuel flow path, and the anode exhaust gas pipe A downstream shut-off valve, and The detection value of the force sensor is received, the first fuel cutoff valve, the second fuel cutoff valve, and the downstream side cutoff valve are provided to be openable and closable, and the first fuel cutoff valve and the downstream side cutoff valve are closed. In addition, when the second fuel cutoff valve is opened and the detected value of the pressure sensor increases with time, it is determined that a seat leak has occurred in the first fuel cutoff valve, and the second fuel cutoff valve and the downstream side A controller for closing the side shut-off valve and opening the first fuel shut-off valve to determine that a seat leak has occurred in the second fuel shut-off valve when the detected value of the pressure sensor increases with time; It is characterized by having.

  The present invention also provides a reformer that generates a hydrogen-rich reformed gas from a raw fuel gas containing hydrocarbons, a raw fuel gas supply pipe that supplies the raw fuel gas to the reformer, and the raw fuel A first fuel cutoff valve provided in a gas supply pipe; a second fuel cutoff valve provided downstream of the first fuel cutoff valve in the raw fuel gas supply pipe; and an anode formed with a fuel flow path And a fuel cell body having a cathode in which an oxidant channel is formed, a reformed gas supply pipe connecting the reformer and the fuel channel, and a downstream end of the fuel channel In the inspection method during the stoppage of power generation in the fuel cell power generation system, comprising: the anode exhaust gas pipe formed; and the downstream cutoff valve provided in the anode exhaust pipe. The first fuel cutoff valve and the downstream cutoff valve include Close and open the second fuel shut-off valve A first measurement step of measuring the pressure inside the raw fuel gas supply pipe downstream of the second fuel cutoff valve, and the first fuel cutoff valve when the pressure measured in the first measurement step increases with time Determining that a seat leak has occurred, closing the second fuel shut-off valve and the downstream shut-off valve and opening the first fuel shut-off valve, and downstream of the second fuel shut-off valve, the raw fuel A second measurement step of measuring the pressure inside the gas supply pipe, and a step of determining that a seat leak has occurred in the second fuel cutoff valve when the pressure measured in the second measurement step increases with time It is characterized by having.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to confirm easily the double interruption | blocking of the raw fuel in the raw fuel system | strain of a fuel cell power generation system.

It is a block diagram in one embodiment of a fuel cell power generation system according to the present invention. It is a flowchart of the inspection method in one embodiment of the fuel cell power generation system according to the present invention.

  An embodiment of a fuel cell power generation system according to the present invention will be described with reference to the drawings. Note that this embodiment is merely an example, and the present invention is not limited thereto.

  FIG. 1 is a block diagram of an embodiment of a fuel cell power generation system according to the present invention.

  The fuel cell power generation system of the present embodiment includes a raw fuel gas supply pipe 19, a reformer 12, a carbon monoxide converter 13, a carbon monoxide remover 14, a fuel cell main body 11, and a controller 15. It has. The fuel cell main body 11 includes an anode in which a fuel channel is formed and a cathode in which an oxidant channel is formed.

  The raw fuel gas supply pipe 19 connects a supply source for supplying raw fuel such as city gas containing hydrocarbons and the reformer 12, and supplies the raw fuel gas to the reformer 12. In the middle of the raw fuel gas supply pipe 19, a first fuel cutoff valve 16 and a second fuel cutoff valve 17 are provided in series. The second fuel cutoff valve 17 is provided on the downstream side of the first fuel cutoff valve 16. A pressure sensor 18 is attached to the raw fuel gas supply pipe 19 downstream of the second fuel cutoff valve 17.

  The controller 15 is connected to the pressure sensor 18 and receives a signal indicating the pressure measured by the pressure sensor 18. The first fuel cutoff valve 16 and the second fuel cutoff valve 17 are electromagnetic valves that are opened and closed by the controller 15.

  The reformer 12 reforms the supplied raw fuel into a hydrogen-rich reformed gas. A reformed gas supply pipe 21 extends between the reformer 12 and the fuel flow path of the fuel cell main body 11. The reformed gas generated by the reformer 12 contains carbon monoxide. Carbon monoxide contained in the reformed gas is removed by a carbon monoxide converter 13 and a carbon monoxide remover 14 provided in the middle of the reformed gas supply pipe 21. The reformed gas is supplied to the anode of the fuel cell body 11 after carbon monoxide is removed.

  The fuel cell main body 11 generates power using oxygen contained in the air supplied to the oxidant flow path and hydrogen gas contained in the reformed gas supplied to the fuel flow path. The gas supplied to the fuel flow path of the fuel cell main body 11 is reduced in hydrogen concentration by the cell reaction, and is discharged from the anode exhaust gas pipe 20 connected to the downstream side of the fuel flow path. The end of the anode exhaust pipe 20 opposite to the fuel cell main body 11 is open to the atmosphere. A downstream shut-off valve 24 is provided in the anode exhaust gas pipe 20.

  The anode exhaust gas pipe 20 may be connected to the reformer 12 or the like between the fuel cell main body 11 and the open end in order to use hydrogen that has not been used in the cell reaction as a fuel such as a burner. Further, a bypass pipe provided with a bypass valve may be provided between the reformed gas supply pipe and the anode exhaust gas pipe.

  In such a fuel cell power generation system, the pressure sensor 18 installed downstream of the first fuel cutoff valve 16 and the second fuel cutoff valve 17 is used to seat the first fuel cutoff valve 16 and the second fuel cutoff valve 17. Detect leaks. The inspection of the fuel leak valve seat leak is performed while the fuel cell power generation system is stopped, that is, while the fuel cell main body 11 is stopped.

  FIG. 2 is a flowchart of the inspection method in the present embodiment.

  In the inspection of the fuel leakage of the fuel cutoff valve, first, the first fuel cutoff valve 16 is closed, the second fuel cutoff valve 17 is opened, and the downstream cutoff valve 24 downstream of the fuel system is opened. The part downstream from the outlet of the valve 16 is opened to the atmosphere (S1). Next, the downstream shut-off valve 24 is closed (S2), and it is confirmed whether or not the detection value of the pressure sensor 18 increases (S3).

  If the first fuel cutoff valve 16 is healthy, the detected value of the pressure sensor 18 should not increase even if the second fuel cutoff valve 17 is opened. When there is a seat leak in the first fuel cutoff valve 16, the supply pressure of the raw fuel is applied to the pressure sensor 18, and the detected value rises to about the supply pressure. If an increase is detected in the detection value of the pressure sensor 18, it is determined that the seat leak of the first fuel cutoff valve 16 (S8).

  Subsequently, the second fuel cutoff valve 17 is closed (S4), and then the first fuel cutoff valve 16 is opened (S5), and it is confirmed whether the detected value of the pressure sensor 18 increases (S6). If the second fuel cutoff valve 17 is healthy, the detection value of the pressure sensor 18 should not increase even if the first fuel cutoff valve 16 is opened. When there is a seat leak in the second fuel cutoff valve 17, the supply pressure of the raw fuel is applied to the pressure sensor 18, and the detected value rises to about the supply pressure. If an increase is detected in the detection value of the pressure sensor 18, it is determined that the seat leak of the second fuel cutoff valve 17 (S9).

  In any of the above cases, when no increase is observed in the detection value of the pressure sensor 18, it is determined that the first fuel cutoff valve 16 and the second fuel cutoff valve 17 are in a healthy state with no seat leak (S7). .

  This inspection of the fuel shut-off valve seat leak is performed, for example, every time power is turned on to the fuel cell power generation system. Alternatively, it may be performed each time the fuel cell power generation system is started, that is, the fuel cell main body 11 starts power generation. Further, the fuel cell power generation system may be periodically inspected during the stop period.

  Further, during power generation by the fuel cell system, the first fuel cutoff valve 16 and the second fuel cutoff valve 17 are normally open. For this reason, a part of the valve may be stuck for some reason and cannot be closed. Accordingly, the seat leak inspection of the fuel cutoff valve may be performed immediately after the fuel cell system is stopped.

  If it is determined that a seat leak has occurred in at least one of the first fuel cutoff valve 16 and the second fuel cutoff valve 17, the controller 15 may be configured to stop the activation of the system. Further, the controller 15 may be configured to issue an alarm when it is determined that at least one of the first fuel cutoff valve 16 and the second fuel cutoff valve 17 has a seat leak.

  As described above, in the fuel cell power generation system according to the present embodiment, it is possible to easily confirm the double cutoff of the raw fuel in the raw fuel system. For this reason, the fuel cell power generation system can confirm double blocking of the raw fuel easily and frequently. Therefore, the maintenance cost of the fuel cell power generation system can be reduced and the safety can be improved. In addition, the burden on the user for confirming double shutoff of raw fuel is small.

DESCRIPTION OF SYMBOLS 11 ... Fuel cell main body, 12 ... Reformer, 13 ... Carbon monoxide converter, 14 ... Carbon monoxide remover, 15 ... Controller, 16 ... 1st fuel cutoff valve, 17 ... 2nd fuel cutoff valve, 18 ... Pressure sensor, 19 ... Raw fuel gas supply pipe, 20 ... Anode exhaust gas pipe, 21 ... Reformed gas supply pipe, 24 ... Downstream shutoff valve

Claims (4)

A reformer that produces hydrogen-rich reformed gas from a raw fuel gas containing hydrocarbons;
Raw fuel gas supply piping for supplying raw fuel gas to the reformer;
A first fuel cutoff valve provided in the raw fuel gas supply pipe;
A second fuel cutoff valve provided downstream of the first fuel cutoff valve of the raw fuel gas supply pipe;
A pressure sensor provided downstream of the second fuel cutoff valve of the raw fuel gas supply pipe;
A fuel cell body comprising an anode formed with a fuel flow path and a cathode formed with an oxidant flow path;
A reformed gas supply pipe connecting the reformer and the fuel flow path;
An anode exhaust gas pipe connected to the downstream end of the fuel flow path;
A downstream shut-off valve provided in the anode exhaust gas pipe;
The detection value of the pressure sensor is received, and the first fuel cutoff valve, the second fuel cutoff valve, and the downstream cutoff valve are provided to be openable and closable, and the first fuel cutoff valve and the downstream cutoff valve are provided. When the detected value of the pressure sensor increases with time by closing and opening the second fuel cutoff valve, it is determined that a seat leak has occurred in the first fuel cutoff valve, and the second fuel cutoff valve and the A controller that determines that a seat leak has occurred in the second fuel cutoff valve when the downstream side cutoff valve is closed and the first fuel cutoff valve is opened and the detected value of the pressure sensor increases with time; ,
A fuel cell power generation system comprising:   The controller is configured not to cause the fuel cell body to start power generation when it is determined that seat leak has occurred in at least one of the first fuel cutoff valve and the second fuel cutoff valve. A fuel cell power generation system.   The controller is configured to issue an alarm when it is determined that a seat leak has occurred in at least one of the first fuel cutoff valve and the second fuel cutoff valve. system. A reformer for generating hydrogen-rich reformed gas from a raw fuel gas containing hydrocarbons, a raw fuel gas supply pipe for supplying the raw fuel gas to the reformer, and the raw fuel gas supply pipe; A first fuel cutoff valve, a second fuel cutoff valve provided downstream of the first fuel cutoff valve of the raw fuel gas supply pipe, an anode in which a fuel channel is formed, and an oxidant channel. A fuel cell main body having a formed cathode; a reformed gas supply pipe connecting the reformer and the fuel flow path; an anode exhaust gas pipe connected to an end portion on the downstream side of the fuel flow path; In the inspection method during the power generation stop of the fuel cell power generation system, comprising a downstream side shutoff valve provided in the anode exhaust gas pipe,
A first measurement step of measuring the pressure inside the raw fuel gas supply pipe downstream of the second fuel cutoff valve by closing the first fuel cutoff valve and the downstream side cutoff valve and opening the second fuel cutoff valve When,
Determining that a seat leak has occurred in the first fuel cutoff valve when the pressure measured in the first measurement step increases with time;
A second measuring step of closing the second fuel cutoff valve and the downstream side cutoff valve and opening the first fuel cutoff valve to measure the pressure inside the raw fuel gas supply pipe downstream of the second fuel cutoff valve; When,
A step of determining that a seat leak has occurred in the second fuel cutoff valve when the pressure measured in the second measurement step increases with time;
A method for inspecting a fuel cell power generation system, comprising:

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