JPS63973A - Operating method for fuel cell - Google Patents

Abstract

PURPOSE:To reduce sufficiently the pressure difference generated in an emergent stop, by operating a cut-off or a flow restriction of a cathode inlet flow control valve at a specific time after the pressure difference between the gas space of the cathode and that of the anode passes the maximum value. CONSTITUTION:To a control device 14 to operate the anode and the cathode flow control valves 6 and 8, a load cut-off signal is input from a cut-off command device 18, and the signal from a pressure difference transmitter 13 is input at the same time. Especially, the signal from the pressure difference transmitter 13 is arranged to input to the control device 14 to control the cathode inlet flow control valve 6. Although the operation in the load cut-off condition is carried out to reduce or cut off the hydrogen gas flow by the anode inlet flow control valve 8 just at the time of the load out-off command, the flow cut-off or reduction of the cathode inlet flow control valve 6 is operated at an adequate time after the pressure difference between the anode and the cathode spaces passes the maximum value. Therefore, the cathode space pressure is delayed, and the pressure difference with the anode space can be made smaller sufficiently.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to how to operate a fuel cell, and particularly to how to operate a fuel cell during sudden load changes or load interruptions.

[Conventional technology]

To explain the operating method of this type of battery that has been generally adopted in the past, together with a schematic plant of the fuel cell, in Fig. 3, 1 is a battery container, 2 is a cathode gas space, and 3 is a fuel cell.
The gas space of the anode is shown. In a steady state, nitrogen flows into the battery container from the inlet side through the valve 4.
On the outlet side, the cathode is connected via a pressure loss element 5 on the downstream side. In the cathode system, air flows into the gas space 2 of the cathode via the cathode inlet flow control valve 6, generating a t-flow and consuming the necessary oxygen. It is then discharged to the downstream side of the cathode. After combining with nitrogen from the battery container, it flows into the reformer combustion apparatus 11 through a pressure loss 7 such as a heat exchanger and a nozzle of the reformer combustion section. In the 10,000 anode system, reformed gas containing hydrogen generated on the reformer process side (not shown) flows into the anode gas space 3 via the anode inlet flow control valve 8, consuming the hydrogen necessary for power generation. . Thereafter, it flows into the reformer combustion equipment [11] through a pressure loss 10 formed by, for example, a heat exchanger, a nozzle of the reformer combustion equipment, and the like and a differential pressure control valve 9 installed on the downstream side of the anode.

Also, the conceptual path of the DC current generated in the battery is 12A,
Shown as 12B. The DC current generated by the battery is further connected to external equipment via a DC breaker 13.

To explain the operating method in such a plant, Fig. 4 shows a time chart of the emergency stop operation method.
At the same time, the cathode inlet flow rate and the anode inlet flow rate are decreased (by the B disconnection command device 18, the control device 14, and the valves 6 and 8).

[Problem that the invention seeks to solve]

In this case, as shown in FIG. 2, the load current is cut off instantaneously, but since the flow rate control valve operates mechanically, it takes more time to cut it off or reduce the flow rate to a predetermined level than when cutting off the current.

Therefore, after the current is cut off, the consumed hydrogen becomes redundant in the gas space of the anode, reducing the anode inlet flow rate, and the differential pressure control valve 9 (operated by the differential pressure transmitter 16) on the anode outlet side is activated.
The pressure on the gas space side of the anode will increase until the pressure difference between the cathode and anode gas spaces can be adjusted. When the load is cut off, the flow rate on the anode side must be reduced to a predetermined flow rate or cut off as quickly as possible to allow a predetermined flow rate of nitrogen to flow in. In this operating method, even if the anode is alone, the pressure of the anode is lower than that of the cathode. However, since the cathode inlet flow rate is further decreased, the differential pressure between the cathode and the anode further increases by K, and the battery K
There was a dislike that had a negative influence on me.

Regarding this type of operation method, Japanese Patent Application Laid-open No. 1983-
No. 149659 is mentioned.

The present invention has been made in consideration of the above, and its purpose is to provide a method of operating a fuel cell that can sufficiently reduce the differential pressure generated during an emergency stop of a fuel cell plant. be.

[Means for solving problems]

That is, the present invention controls the anode inlet flow t control valve K for regulating the flow rate of gas containing hydrogen, the signal of the differential pressure transmitter υ
At a predetermined point after the differential pressure between the gas space of the cathode and the gas space of the anode has passed the maximum value, the cathode inlet flow rate control valve is shut off or the flow rate is reduced, thereby achieving the desired purpose. It was designed to be achieved.

[Embodiments of the invention]

The present invention will be explained below based on the illustrated embodiments.

FIG. 1K shows a schematic diagram of the plant for explaining its operating method. The same devices and parts as in FIG. 3 described above are given the same reference numerals.

In FIG. 1, anode and cathode flow control valves 6,
The control device 14K that operates the control device 8 is configured so as to receive not only the load current cutoff signal from the cutoff command device 18 but also the signal from the differential pressure transmitter 13 as in the conventional case. . In this case, the signal from the differential pressure transmitter is particularly configured to be input to the control device 14K that controls the cathode inlet flow control valve 6.

And what about operation during load shedding? Simultaneously with the load cutoff command, the anode inlet flow rate control valve 8 reduces or cuts off the flow rate of hydrogen gas, but the flow rate of the cathode inlet flow rate control valve 6 is cut off or reduced only when the differential pressure between the cathode space and the anode space is at its maximum. It is done at a suitable time after passing through the value.

When the K operation is performed in this manner, the pressure on the cathode space side is temporally shifted, and the pressure difference with the anode space can be made sufficiently small.

〔Effect of the invention〕

As described above, the present invention incorporates a signal from a differential pressure transmitter to control the anode inlet flow rate control valve that regulates the flow rate of hydrogen-containing gas, and the differential pressure between the cathode gas space and the anode gas space is Since the cathode inlet flow control valve is shut off or the flow rate is reduced at a predetermined point after passing the maximum value, it is possible to sufficiently reduce the differential pressure that occurs during an emergency stop of the fuel cell plant. Can be done.

[Brief explanation of the drawing]

Fig. 1 is a schematic plant diagram for explaining the operating method of the fuel cell of the present invention, Fig. 2 is a time chart of the operating method, and Fig. 3 is a schematic plant diagram for explaining the operating method of the conventional fuel cell. 4 are time charts of the operating method. 2...Cathode gas space, 3...Anode gas space, 6...Cathode inlet flow rate control valve S8...Anode inlet R. Volume control valve, 9...Differential pressure control valve, 11...
・Reho? Combustion device, 13... DC circuit breaker, 14...
-Control device, 16...differential pressure transmitter.

Claims (1)

[Claims] 1. An anode into which a hydrogen-containing gas flows through an anode inlet flow rate control valve and consumes the hydrogen necessary for generating electric current;
a cathode disposed adjacent to the anode, into which air enters through a cathode inlet flow control valve to consume the oxygen necessary for current generation; a differential pressure transmitter that detects and issues a signal; a differential pressure regulating valve that operates based on the signal from the differential pressure transmitter to adjust the differential pressure between the cathode gas space and the anode gas space; and the cathode and anode gas space. a reformer combustion device that burns exhaust gas from the anode/cathode, a DC breaker that interrupts the direct current generated from the anode/cathode, and a control device that controls the anode inlet and cathode inlet flow rate control valves, and a load current interrupter. In the method of operating a fuel cell, the anode inlet flow rate control valve and the cathode inlet flow rate control valve are operated by the control device to reduce or cut off the gas flow rate, wherein the anode inlet flow rate control valve adjusts the flow rate of the hydrogen-containing gas. The signal from the differential pressure transmitter is taken in to control the cathode inlet flow rate control valve or the flow rate is adjusted at a predetermined point after the differential pressure between the cathode gas space and the anode gas space has passed the maximum value. A method of operating a fuel cell, characterized by causing a reduction operation to be performed.