JPH0794200A - Reactive air supply device for fuel cell power generation system - Google Patents

Abstract

(57) [Summary] [Purpose] By simply and efficiently removing trace amounts of impurity gas components such as organic solvents contained in reaction air,
Eliminates adverse effects on cell characteristics. [Structure] A reaction air supply device (10) is a filter (6), a blower (7), and an impurity adsorption device (11) as an impurity removing means.
And the adsorbent in the impurity adsorbing device adsorbs the impurity gas component such as the organic solvent contained in the pretreated air 6A from which the dust is removed to purify the reaction air 13A. The deterioration of the electrolyte and the decrease of the oxygen adsorption capacity of the electrode catalyst caused by the supply to the air electrode of the fuel cell stack 1 and the deterioration of the cell characteristics caused by these are prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel cell power generation system for generating electric power by an electrochemical reaction between hydrogen-rich fuel gas and reaction air as an oxidant, and a clean reaction air at the oxidizer electrode of the fuel cell. The present invention relates to a reaction air supply device for supplying air.

[0002]

2. Description of the Related Art FIG. 4 is a system configuration diagram showing a main part of a fuel cell power generation system. A fuel cell power generation system including a fuel cell stack 1 composed of a stack of unit cells uses fossil fuel and hydrocarbon fuel. A fuel processing device 2 that reforms to hydrogen-rich fuel gas and supplies it to the fuel electrode of the fuel cell 1, and an air supply device 3 that supplies reaction air as an oxidant to the oxidant electrode (air electrode) of the fuel cell 1. And a power converter 4 that converts the output DC power of the fuel cell 1 into AC power and supplies the AC power to an external load, and a controller 5 that controls these units.

When the fuel cell power generation system configured as described above is operated, the control device 5 receives the load change command 9S to increase or decrease the power supplied to the external load. Control signal 2 directed toward
S, 3S, control signal 4 issued to the power converter 4
S, and the control signal 1S emitted to the fuel cell stack 1, etc., and the load changes such as the supply amount of fuel gas and reaction air, the power supplied to an external load, the utilization rate of hydrogen and oxygen in the fuel cell stack, and the like. The AC power that is controlled to match the respective target values corresponding to the command 9S and that is maintained at a constant voltage is supplied to the external load.

FIG. 5 is a block diagram showing an example of the simplest structure of a conventional reaction air supply apparatus. The reaction air supply apparatus 3 is composed of a filter 6 and a blower 7, and dust is removed by the filter-6. The pretreated air is supplied to the oxidizer electrode (air electrode) of the fuel cell stack 1 as reaction air 3A. When the fuel cell is of the pressurized type, a turbo compressor is used instead of the blower, and a preheater is provided and the reaction air temperature is raised to near the operating temperature of the fuel cell. It is also known to be configured to supply a battery.

[0005]

In the conventional reaction air supply apparatus, the reaction air 3A is generated by a simple pretreatment for removing dust contained in the air (outside air) around the fuel cell power generation system. Therefore, when the outside air contains an impurity gas component such as an organic solvent vapor, the reaction air 3A containing the impurity gas component is directly supplied to the air electrode of the fuel cell stack 1. By the way, in the case of a phosphoric acid fuel cell, for example, the unit cell is a fuel electrode and an air electrode supporting an electrode catalyst layer on one surface of a porous electrode base material, and phosphoric acid as an electrolyte sandwiched between them. The oxygen in the reaction air permeates the electrode substrate and reaches the interface of the electrocatalyst that is wet with phosphoric acid to cause an electromotive reaction based on an electrochemical reaction. Therefore, the impurity gas contained in the reaction air permeates the electrode base material together with oxygen to reach the electrode catalyst layer, contacts the electrolyte to cause a chemical reaction, and the chemical reaction changes the electrolyte to function as an electrolyte. And the oxygen adsorbing function of the electrode catalyst is hindered, which causes a problem that the cell characteristics and life characteristics of the fuel cell are deteriorated.

An object of the present invention is to eliminate adverse effects on cell characteristics by simply and efficiently removing a trace amount of impurity gas components such as an organic solvent contained in reaction air.

[0007]

In order to solve the above-mentioned problems, according to the present invention, pre-treated air from which dust has been removed is supplied as reaction air to an oxidizer electrode of a fuel cell. An impurity removing means for removing an impurity gas component such as an organic solvent contained in the above is provided.

The impurity removing means includes an adsorbent layer of an organic solvent. The impurity removing means includes an organic solvent combustion catalyst layer. The impurity removing unit includes an organic solvent combustion catalyst layer and an organic solvent adsorbent layer.

[0009]

In the present invention, the reaction air supply device is provided with the impurity removing means for removing the impurity gas such as the organic solvent contained in the reaction air, so that the clean reaction air containing no impurity gas can be supplied to the fuel electrode. To prevent deterioration of the electrolyte due to the chemical reaction between the impurity gas and the electrolyte and deterioration of the oxygen adsorption capacity of the electrode catalyst, and to avoid the deterioration of cell characteristics caused by these.

As an impurity removing means, an organic solvent adsorbent,
For example, if an activated carbon layer is used, the action of adsorbing the impurity gas and purifying the reaction air can be obtained. Further, if a combustion catalyst of an organic solvent, for example, a platinum alloy catalyst layer is used as the impurity removing means, a function of bringing the impurity gas in the reaction air into contact with the catalyst for combustion decomposition and detoxification is obtained.

Furthermore, if a series connection body of an organic solvent combustion catalyst layer and an organic solvent adsorbent layer is used as the impurity removing means, after the impurity gas is combusted and decomposed in the combustion catalyst layer, the residual impurity gas is further adsorbed. It becomes possible to adsorb and remove the agent layer, and a stable purifying action can be obtained even for reaction air having a high impurity gas concentration.

[0012]

EXAMPLES The present invention will be described below based on examples. FIG. 1 is a configuration diagram showing a reaction air supply device of a fuel cell power generation system according to an embodiment of the present invention, and the same components as those in the prior art are designated by the same reference numerals, and a duplicate description will be omitted. In the figure, a reaction air supply device 1
0 is provided with an impurity adsorbing device 11 in which a container is filled with an adsorbent such as activated carbon as an impurity removing means, and the pretreated air 6A from which dust sent to the impurity adsorbing device via the filter 6 and the blower 7 is removed is the impurity. Since the adsorbent adsorbs impurity gas components such as a trace amount of organic solvent contained in the pretreated air 6A by coming into contact with the adsorbent in the adsorption device 11,
It becomes possible to supply the reaction air 13A in a clean state in which dust is adsorbed and removed by the impurity adsorbing device 11 by the filter 6 to the oxidant electrode of the fuel cell stack 1 by the filter 6. Therefore, it becomes possible to prevent alteration of the electrolyte based on the chemical reaction between the impurity gas component and the electrolyte, and to prevent the oxygen adsorption capacity of the electrode catalyst from decreasing.
It is possible to avoid the deterioration of cell characteristics caused by this in the past,
The advantage of extending the life of the fuel cell is obtained.

FIG. 2 is a block diagram showing a reaction air supply apparatus according to another embodiment of the present invention.
0 is equipped with a catalytic combustion catalyst device 21 for combustible gas such as an organic solvent as an impurity removing means, which is different from the above-mentioned embodiment, and is pretreated by using, for example, a platinum alloy catalyst as the catalytic combustion catalyst. Since the combustible impurity gas component contained in the reaction air 6A comes into contact with the platinum alloy catalyst and is decomposed by combustion, the reaction air 23A from which the impurity gas component such as the organic solvent is removed is supplied to the air electrode of the fuel cell stack 1. The advantage that can be supplied is obtained.

FIG. 3 is a block diagram showing a reaction air supply device according to a further different embodiment of the present invention. The reaction air supply device 30 serves as an impurity removing means 31 and a catalytic combustion catalyst device 21 for a combustible gas such as an organic solvent. , Is different from each of the above-described embodiments in that it is configured as a series body with the impurity adsorbing device 11 in which a container is filled with an adsorbent such as activated carbon. By using, for example, a platinum alloy catalyst as the catalytic combustion catalyst, Since the flammable impurity gas component contained in the pretreated reaction air 6A comes into contact with the platinum-based alloy catalyst for combustion decomposition, and the adsorbent adsorbs and removes the remaining trace amount of the impurity gas component such as the organic solvent, For example, the pretreated air 6A transiently containing high-concentration organic solvent vapor is the impurity removing means 3
Even if the reaction gas flows into 0, the reaction air supply device 30 is provided with an impurity removal means having a high impurity gas removal performance capable of combustion-decomposing and further adsorbing and removing these to supply reaction air 33A in a clean atmosphere to the fuel cell. Is obtained.

As described above, in order to verify the impurity gas removing performance of the impurity removing means 11, 21, and 31 shown in FIGS. 1, 2 and 3, toluene, acetone and xylene are each 100 ppm as the organic solvent gas component. The simulated reaction air containing the same was passed through the reaction air supply devices 10, 20, and 30, and the organic solvent gas concentrations in the obtained reaction air 13A, 23A, and 33A were measured using a gas concentration measuring device. As a result, in any reaction air supply device, the organic solvent gas concentration falls below the detection limit of the gas concentration measuring device, and the catalytic combustion catalyst device 21 for combustible gas such as an organic solvent, the impurities filled with the adsorbent such as activated carbon, etc. It was demonstrated that both the adsorption device 11 and the in-line body of both have high organic solvent gas component removal performance.

[0016]

As described above, the present invention provides a catalytic combustion catalyst device, an impurity adsorbing device, as an impurity removing means for removing an impurity gas such as an organic solvent contained in the reaction air by the reaction air supply device of the fuel cell. Alternatively, it is configured so as to have either of the two series bodies. As a result, a minute amount of impurity gas components such as organic solvent contained in the pretreated reaction air from which dust has been removed can be decomposed by combustion or adsorbed and removed to supply clean reaction air to the air electrode of the fuel cell stack. When the reaction air containing the impurity gas component is supplied to the air electrode of the fuel cell stack as it is, the deterioration of the electrolyte that has occurred in the conventional fuel cell and the resulting deterioration of the electrolyte function, or the oxygen adsorption of the electrode catalyst It is possible to provide a fuel cell power generation system equipped with a reaction air supply device that can prevent the deterioration of the performance of the fuel cell, eliminate the problem that the cell characteristics of the fuel cell deteriorate due to these, and prolong the life of the fuel cell. .

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a reaction air supply device of a fuel cell power generation system according to an embodiment of the present invention.

FIG. 2 is a configuration diagram showing a reaction air supply device according to another embodiment of the present invention.

FIG. 3 is a configuration diagram showing a reaction air supply device according to a further different embodiment of the present invention.

FIG. 4 is a system configuration diagram showing a main part of a fuel cell power generation system.

FIG. 5 is a block diagram showing an example of the simplest configuration of a conventional reaction air supply device.

[Explanation of symbols]

1 Fuel Cell Stack 2 Fuel Reforming Device 3 Reactive Air Supply Device 4 Power Converter 5 Control Device 6 Filter-7 Blower 10 Reactive Air Supply Device 11 Impurity Removal Means (Impurity Adsorption Device) 20 Reactive Air Supply Device 21 Impurity Removal Means ( Catalytic combustion catalyst device) 31 Impurity removing means (serial body of combustion catalyst device and impurity adsorption device)

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Yasumiki Kubota 1-1 Tanabe Nitta, Kawasaki-ku, Kawasaki-shi, Kanagawa Fuji Electric Co., Ltd.

Claims (4)

[Claims] 1. In a device for supplying pretreated air from which dust has been removed to an oxidizer electrode of a fuel cell as reaction air, an impurity removing means for removing an impurity gas component such as an organic solvent contained in the reaction air is provided. A reaction air supply device for a fuel cell power generation system characterized by the following. 2. The reactive air supply device for a fuel cell power generation system according to claim 1, wherein the impurity removing means includes an adsorbent layer of an organic solvent. 3. The reaction air supply apparatus for a fuel cell power generation system according to claim 1, wherein the impurity removing means includes a combustion catalyst layer of an organic solvent. 4. The reactive air supply apparatus for a fuel cell power generation system according to claim 1, wherein the impurity removing means includes an organic solvent combustion catalyst layer and an organic solvent adsorbent layer.