JPS6132363A - Fuel cell power generation system - Google Patents

Abstract

PURPOSE:To suppress the pressure difference between the fuel system and the oxidant system by connecting a fuel supply pipe, an oxidant supply pipe and an inactive gas supply pipe together by breaking valves and gradually closing the breaking valves at the end of purging. CONSTITUTION:A fuel cell 1 where a fuel gas and an oxidant gas are supplied and discharged through pipes 9a and 9b and pipes 10a and 10b, is installed in a pressure case 8 where an inactive gas is supplied and discharged through pipes 11a and 11b. The fuel supply pipe 9a, the oxidant supply pipe 10a and the inactive gas supply pipe 11a are connected together by purge pipes 12 and 13 which have breaking valves 14 and 15 controlled by valve-closure-controlling element 19 and 20. Because of the above structure, it is possible to prevent gas crossing by suppressing the pressure difference between the fuel system and the oxidant system by purging the inactive gas by opening the breaking valves 14 and 15 and then gradually decreasing the amount of the inactive gas fed into the fuel cell 1 by controlling the breaking valves 14 and 15.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a fuel cell power generation system, and particularly to a fuel cell power generation system suitable for use when a stacked battery in which a large number of single cells are stacked is housed in a container.

[Background of the invention]

Fuel cells, which produce electrical energy from a fuel and an oxidant, have been known for a long time.

This fuel cell consists of a fuel electrode, an oxidizer electrode attached to the fuel electrode, an electrolyte disposed between these two electrodes in contact with both electrodes, a separator that also serves as a current collector, and a combination of the fuel electrode, oxidizer electrode, and separator. A fuel gas filled in between and a passage for an oxidizing agent are the basic structure of a single cell, and a plurality of these single cells are stacked to form a stacked battery body.

In such a case, a liquid-cooled or gas-cooled cooling plate may be inserted into the stacked battery body to control the temperature of the stacked battery body.

In this case, in order to supply fuel gas and oxidant gas to the stacked battery main body, a manifold is installed around the outside of the stacked battery main body, or a manifold is installed around the internal periphery of the stacked battery main body. It will be done.

In a fuel cell power generation system having such a configuration, the inside of the cell and the gas supply system are purged with an inert gas before operation as a fuel cell.

This is to avoid oxidation, combustion, or explosion due to mixing of residual gas in the battery and gas supply system with fuel gas or oxidizing gas that flows in during operation.

Conventionally, an operation method was adopted in which fuel gas and oxidant gas were supplied after the inert gas purge was completed, but in this method, there was no pressure change or change when switching from inert gas to fuel gas and oxidant gas. This caused gas cross in the stacked battery body.

[Purpose of the invention]

An object of the present invention is to provide a fuel cell power generation system that can suppress pressure changes that occur when fuel gas and oxidant gas flow in after an inert gas barge.

[Summary of the invention]

The present invention communicates between an inert gas supply pipe and at least one of a fuel gas supply pipe and an oxidant gas supply pipe via a shutoff valve, and gradually reduces the amount of blocked inflow. It is characterized by the following.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings.

FIGS. 1 and 2 are a cross-sectional view and a vertical cross-sectional view of a main part of a fuel cell power generation system.

Laminated battery body 2 consisting of multiple cells and cooling cells
is installed on pace 3, and manifold 4 is installed around it.
a, 4b, 5a, and 5b are attached. pace 3
A bolt 7 bridges between the fastening fitting 6 and the pace 3 which face each other, and proper tightening applies pressure to the stacked battery body 2.

Such a structural unit is housed in a pressure vessel 8 and connected to a load (not shown). manifold 4a,
A fuel supply pipe 9a and a discharge pipe 9b are connected to 4b,
An oxidizing agent supply pipe 10a and a discharge pipe 10b are connected to the manifolds 5f and 5b, and an inert gas supply pipe 11a and a discharge pipe 11b are further connected to the pressure vessel 8.

Between the fuel supply pipe 9a and the inert gas supply pipe 112, and between the inert gas supply pipe 11a and the oxidizer supply pipe 108, purge pipes 12 each have a shutoff valve 14, 15.
．． It is connected by 13. Each shut-off valve 14.15 is associated with a valve-closing control element 19.20. Shutoff valves 16, 17 and 1 are installed in the fuel supply pipe 9a, inert gas supply pipe 10a and oxidizer supply pipe 11g, respectively.
8 is provided in the purge pipes 12 and 13, and check valves 21 and 22 are provided in the purge pipes 12 and 13 to allow inflow in the direction of the arrow and from the active gas supply pipe 11a to the fuel supply pipe 9a and the oxidizer supply pipe 10a. It is connected.

In such a configuration, fuel is supplied from the fuel supply pipe 9a,
That is, reformed gas, by-product hydrogen from a chemical plant, cylinder filling gas, etc., as well as air from the atmosphere by a compressor, cylinder filling air, etc., are supplied from the oxidizing agent supply pipe 10a to the main body of the stacked battery. On the other hand, the pressure vessel 8 is supplied with evaporated gas from liquid nitrogen, cylinder filling gas, etc. from an inert gas supply pipe 11a.

Next, the procedure for supplying these gases will be explained.

First, close the shutoff valves 16 and 17, open the shutoff valve 18, and open the container 8.
At the same time, the shutoff valves 14 and 15 are opened to purge the fuel system flow path and the oxidizer system flow path with the inert gas. At the end of the purge, shutoff valves 16,17 are opened to begin supplying fuel and oxidizer.

However, since the flow rates of fuel and oxidizer are not stable when the shutoff valves 16 and 17 are opened, if the shutoff valves 14 and 15 are closed at this point, the flow rate of fuel and oxidant σ will be 1.
When the pressure is unstable and the pressure difference between the fuel flowing through the stacked battery body 2 and the oxidant is large, this is the source of gas cross in the stacked battery body 2. During this time, the flow rate of the fuel and oxidizer is reduced to a stable area. will be increased. After that, the shutoff valve 14.15
When closed, the flow rate and pressure of the fuel and oxidizer are stabilized, and the differential pressure generated between the fuel system flow path and the oxidizer system flow path of the stacked battery main body 2 can also be reduced.

The above explanation describes the procedure when switching from the inert gas supply to the fuel and oxidizer, but when switching the supply from the fuel and oxidizer to the inert gas, the fuel and The amount of inert gas may be increased while gradually decreasing the amount of oxidizing agent.

Further, backflow from the fuel system and oxidizer system to the inert gas system can be prevented by increasing the pressure of the inert gas, or by using a check valve.

In the above embodiment, both the fuel system and the oxidizer system are purged with an inert gas, but the present invention can also be applied to the case where at least one of the fuel system and the oxidizer system is purged.

FIG. 3 shows the relationship between the operation of each shutoff valve and pressure fluctuation, and FIG. 4 shows the relationship between the operation of each shutoff valve and pressure fluctuation according to the conventional system.

As can be seen from the comparison between the two figures, the pressure change between the fuel system and the oxidizer system is suppressed to a small extent by the shutoff valve 14°, while as shown in FIG. ．．
15 and the valve closing operation control elements 19 and 20, the valve is closed within an extremely short time Δ of seconds, resulting in misalignment and pressure fluctuations between the fuel system and the oxidizer system.

〔Effect of the invention〕

As explained above, the present invention provides a purge pipe with a shutoff valve and attaches a valve-closing operation control element to the shutoff valve, thereby suppressing pressure fluctuations between the fuel system and the oxidizer system and reducing the pressure fluctuation in the stacked battery body. Gas cross can be prevented.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing the main parts of a fuel cell power generation system according to an embodiment of the present invention, FIG. 2 is a longitudinal cross-sectional view showing the main parts of the fuel cell power generation system of FIG. 1, and FIG. FIG. 1 is a characteristic diagram showing the relationship between the operation of each shutoff valve and pressure fluctuation, and FIG. 4 is a characteristic diagram showing the relationship between the operation of each conventional shutoff valve and pressure fluctuation. 2...Laminated battery body, 4a, 4b, 5a, 5b...
Manifold, 8... Pressure vessel, 9a... Fuel supply pipe, 10a... Oxidizer supply pipe, 11a... Inert gas supply pipe, 12.13... Purge pipe, It
, 15... Shutoff valve, 19.20... Valve closing operation control element.

Claims (1)

[Claims] 1. In a fuel cell power generation system comprising a fuel supply pipe, an inert gas supply pipe, and an oxidizer supply pipe for supplying fuel, inert gas, and oxidizer to the stacked battery main body, the fuel supply pipe and the oxidizer supply pipe are connected to each other. At least one of the agent supply pipes and the inert gas supply pipe are connected by a purge pipe having a cutoff valve, and the cutoff valve is provided with a valve closing operation control element. Battery power generation system.