JPS63224157A - Fuel cell device - Google Patents

Abstract

PURPOSE:To make it comparatively easy to control a temperature of the fuel cell device in the caption by directly transmitting combustion heat generated through supply combustible gas and oxidizing gas into a temperature regulator, to a fuel cell laminating body in case of heating operation subfecting a heat medium and the fuel cell laminating body to heat exchange by means of circulation of a cooling heat medium through the temperature regulator in case of cooling operation. CONSTITUTION:A fuel cell laminating body 6 laminating a single or plural fuel cells 5 and a temperature adjusting device 8 close to the fuel cell laminating body 6 are provided and a circular passage is formed with provision of a first inlet 8a, a second inlet 8b and an outlet 8c to cool and heat the fuel cell laminating body 6. When heating operation is conducted, the temperature regulator 8 puts combustible gas F and oxidizing gas B which are led inside the device in the caption through valves in catalytic combustion by action of a catalyzer 9 provided with a fluid circulation passage, oxidizing heat of reaction generated in the above process is transmitted to the fuel cell laminating body 6. In case of cooling, such as oxidizing gas used for heating is made to circulate merely as a heat medium for cooling, to take away heat of a fuel cell device 1. Therefore, a fuel cell device of which temperature control of a fuel cell is comparatively easy can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a fuel cell device in which a plurality of fuel cells are stacked.

[Conventional technology]

Figure 4 is US GRI Report No. FOR-3522
FIG. 2 is a system configuration diagram showing an outline of a fuel cell device and peripheral devices for controlling the temperature of the fuel cell device in a molten carbonate fuel cell power generation system disclosed in No. 2-2. In the figure, (1) is a fuel cell device, and a fuel cell part (la) having a fuel gas electrode and an oxidizing gas electrode,
A fuel gas channel (which supplies fuel gas) to the fuel gas electrode
1b), the main component is an oxidizing gas flow path (LC) that supplies oxidizing gas to the oxidizing gas electrode.

(2) is a charge supply device that recovers power from the exhaust gas (C) discharged from the fuel cell power generation system and boosts the pressure of air (6) from the outside and supplies it; (3) is the fuel cell device (1
) to control the temperature of the circulating gas on the oxidizing gas side circulated by the circulation proa (4) #'i circulation proa which circulates a part of the oxidizing gas (B) (3) heat exchanger, @) indicates the flow of fuel exhaust gas.

Next, I will explain the previous work.

In the fuel cell device (1), a fuel gas (4) is supplied to a fuel gas flow path (ib), and an oxidant gas φ is supplied to an oxidant gas flow path (lc).
] is supplied, and has a fuel cell stack in which one or more fuel cells that cause an electrochemical reaction are stacked, and a part of the chemical energy of the fuel gas (4) is extracted as electrical energy, This is an energy conversion device that converts by-product heat energy into heat energy. For such a fuel cell device (1) to be operated, it is necessary to heat it to a predetermined operating temperature at the start of operation. For example, in the case of a molten carbonate fuel cell device, the temperature is around 650°C.
In the case of a phosphoric acid type fuel cell device, it is necessary to raise the temperature to around 200°C.

On the other hand, during steady operation, it is necessary to remove the fuel energy produced by the fuel cell device (1), that is, to cool it.

As a temperature control method for a fuel cell including both heating and cooling, there are a method of circulating a liquid phase heat medium in the fuel cell device (1), a method of circulating a gas phase heat medium, and the like. In particular, the method of circulating a gas phase heating medium is attracting attention due to its ease of storage and high reliability. In addition, in the case of high-temperature operation fuel cell devices, there is almost no liquid-phase refrigerant available, and relatively low-output fuel cell power generation systems and high-temperature operation type fuel cell devices, such as molten carbonate fuel cell devices, are required. In most of the systems used, a gas phase heating medium is used. Figure 4 shows an example of a power generation system using such a gas-phase heating medium. By recirculating the oxidizing gas to the inlet of the oxidizing gas flow path (1c) of the battery device (1), the oxidizing gas that is the opposite gas is also used as a heating medium for temperature adjustment. When heating the fuel cell device (1), the circulating oxidizing gas, which is a heat medium, is heated in the Fi heat exchanger (4), and conversely, during steady operation, the circulating oxidizing gas is cooled in the heat exchanger (4). As a result, temperature control of the fuel cell device (1) is achieved.

[Problem that the invention seeks to solve]

Since the conventional fuel cell device is configured as described above, it has the following problems.

As an inno heat medium, the heat capacity of a gas phase heat medium is smaller than that of a liquid phase heat medium, so it is difficult to shorten the startup time, especially when it is necessary to quickly raise the temperature of the fuel cell device.

(b) Since it is an indirect heating type in which the heat medium is heated by a heat exchanger, there is a time delay in heating and the thermal efficiency is also poor.

When using zero reactive gas as a heating medium, it is necessary to supply a large amount of reactive gas, for example, about three times as much reactive gas as when not using it. In this case, evaporation and scattering of the electrolyte contained in the fuel cell device is promoted. For this reason, the supply of the reactant gas and the control of the temperature of the fuel cell device interfere with each other, making the control method complicated and shortening the life of the battery. Furthermore, there is a problem in that an increase in proer power due to an increase in the amount of circulation reduces power generation efficiency.

This invention was made to solve the above-mentioned problems, and it is possible to effectively and quickly raise the temperature of a fuel cell device, has high thermal efficiency during heating, and has a It is an object of the present invention to provide a fuel cell device in which the temperature of the fuel cell can be controlled relatively easily by forming a heating and cooling system independent of the system.

Another invention of this invention is that heating and cooling can be performed efficiently with a small amount of heating medium compared to conventional devices, which reduces the amount of electrolyte evaporation caused by the heating medium and reduces the amount of heat required for heating and cooling. The object of the present invention is to obtain a fuel cell device that can reduce blower power loss required for medium circulation.

[Effect]

The fuel cell device according to the present invention includes one or more fuel cells in which fuel gas is supplied from a fuel gas passage to a fuel gas electrode, and oxidizing gas is supplied from an oxidizing gas passage to an oxidizing gas electrode to cause an electrochemical reaction. &@ layered fuel cell stack, a fluid circulation path, a flow regulator that has a catalyst in the circulation path, and a temperature regulator that are installed adjacent to the fuel cell stack to supply combustible gas and oxidizing gas. It is equipped with a heating means that heats the fuel cell stack by supplying and catalytically combusting the fuel cell stack, and a cooling means that cools the fuel cell stack by circulating a cooling heat medium through a temperature controller.

A fuel cell device according to another aspect of the present invention is a fuel cell in which fuel gas is supplied from a fuel gas passage to a fuel gas electrode, and oxidizing gas is supplied from an oxidizing gas passage to an oxidizing gas electrode to cause an electrochemical reaction. A fuel cell stack including a single or multiple layers of A heating means for heating the fuel cell stack by supplying a reactive gas and causing catalytic combustion, and a cooling means for cooling the fuel cell stack by supplying a fluid to a temperature controller to cause an endothermic reaction. [Operation] The heating means in the present invention supplies flammable gas and oxidizing gas to the temperature controller during heating operation to cause catalytic combustion, and directly transmits the combustion heat generated at this time to the fuel cell stack 1ζ. .

On the other hand, the cooling means circulates the cooling heat medium through the temperature controller during the cooling operation, and exchanges heat between the heat medium and the fuel cell stack.

(9) The heating means in another aspect of the present invention is the same as that described above, and the cooling means supplies fluid to the temperature controller during the cooling operation to cause an endothermic reaction, and the endothermic reaction heat at this time Cool the fuel cell stack.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings. 1st
The figure is a partially cutaway side view of a fuel cell device according to an embodiment of the present invention, and in FIG. The fuel cell (6) in the singular is a fuel cell stack in which a plurality of fuel cells (5) are stacked. (η is a gas distributor for supplying reaction gas to the fuel gas flow 1@(lb) and the oxidizing gas flow path (1c), respectively. (8)
is a temperature regulator placed adjacent to the fuel cell stack (6), and the 14th population (8a) introduces flammable gas (F).
, the second fathom inlet (sb) that introduces oxidizing gas, i.e., oxidizing gas
) to form a fluid circulation path, and the fuel cell stack (6)
cooling and heating. (9) is a catalyst installed in the circulation path of the temperature regulator (8). (10) is a premixing part that mixes the supplied combustible gas 5) and oxidizing gas 03), (
11) #-1 is a flashback prevention part that prevents flame flashback during heating operation.

Second factor: Fuel pond device (1) according to an embodiment of the present invention
1 is a configuration diagram showing a fuel cell power generation system to which the above is applied.

In the figure, (2) stiff air supply side i1. (3) A circulation blower for circulating the heat medium, and (4) a heat exchanger.

(L2a) and (12b) are pulps to which the temperature controller (8) supplies flammable gas (g) and oxidizing gas (iv), respectively, during heating operation.

In the figure, (4) indicates the fuel gas flow path (
lb) is supplied to the fuel gas, (B) is the oxidizing gas flow path (
lc), (C) is exhaust gas, @ is air, @) is fuel exhaust gas, (['J is temperature controller (8)
), (G) is the combustion exhaust gas, (
The smell indicates steam.

Next, the operation will be explained.

The temperature regulator (8) according to this embodiment has a combustible gas (12a) and (12b) introduced into the interior through the pulp (12a) and (12b) by the action of a catalyst (9) provided in the circulation path of the introduced fluid during the heating operation. F) and oxidizing gas (to)) are catalytically burned, and the oxidation reaction heat generated at that time is transferred to the fuel cell stack (
6) It functions as a heater by transferring heat to. Specifically, a case will be described in which, for example, the temperature of a molten carbonate fuel cell is raised from room temperature to an operating temperature (approximately 600 to 700°C). First, a combustible gas (F) containing hydrogen as a main component and an oxidizing gas (B) such as air are supplied to the temperature controller (8) to heat the fuel cell device to about 200 to 300°C. In this temperature range, it is difficult to advance the catalytic combustion of hydrocarbons or alcohols with current technology;
It is desirable to use a combustible heating gas containing hydrogen as the main component. In addition, as for the atmospheric conditions of the fuel cell (5), it is sufficient to appropriately supply dry gas. Next, for heating VC of 200 to 300°C or higher, combustible gas (F) mainly consisting of hydrogen may be used, as in the low-temperature range, but lower hydrocarbons such as methane or alcohol may be used as appropriate. good.

In this method, the chemical energy (heat of combustion) of the I-i flammable gas is used to heat the fuel cell, which is different from the conventional method of heating only with the sensible heat of the heating medium (gas). In comparison, a large amount of heat can be supplied with a small gas flow rate.

Specifically, for example, when methane is used as a flammable gas, the heat of oxidation reaction of methane increases the temperature difference between the inlet and outlet during sensible heat transport.
This is approximately 150 times larger than the amount of sensible heat transported at 0°C. Therefore, the heating rate can be dramatically increased compared to the conventional example. Also,? ：The combustion reaction occurs inside the fuel cell device (1) and directly heats the fuel cell device (1), so that there is no time delay and heat loss due to heat radiation is minimized. Can be done.

Next, a description will be given of the cooling operation in which the temperature controller (8) is used to remove thermal energy by-produced in the fuel cell during steady operation. In this case, the temperature controller (8
), no oxidation reaction takes place, and it is simply used as a cooling heat medium.
For example, the oxidizing gas used during heating is circulated to remove heat from the fuel cell device (1).

The heat at this time is carried out of the system through the entire heat exchanger (4).

From a safety standpoint, an inert gas is preferable as the cooling heat medium, and air, nitrogen, or the like is usually used. Therefore, in the power generation system shown in FIG. 2, the pulp (12a) for introducing flammable gas (F) is in the closed state and the pulp (L2b) is in the open state for the cooling operation. During such a cooling operation, the catalyst (9) acts solely as a filler. In this case as well, it is desirable to promote the heat transfer between the cooling heat medium and the catalyst (9), and the shape and packing structure of the catalyst (9) may be used to prevent excessive pressure loss.
) and the cooling heating medium, the catalyst (9) can greatly function as a heat transfer promoting material even during cooling production.

As the catalyst (9), for example, a catalyst prepared by supporting a noble metal such as Pt, Ru, Pd, or Rd on a porous material such as alumina or magnesia is commercially available and can be used as an O.T. By molding granular shapes such as Fi spheres and columns, or by molding the porous material itself into a no-nicum shape, we can create a no-nikum-shaped monolith with holes for gas flow channels. There are net-like things.

Control of the temperature of the temperature regulator (8) during heating operation is as follows:
This is achieved by adjusting the flow rate of the combustible gas (F) supplied and the flow rate of the oxidizing gas (2) supplied per unit flow rate of the combustible gas. Here, it is known that the catalyst (9) usually has poor heat resistance, and when exposed to high temperatures, for example, 800° C. or higher, sintering of the supported metal progresses and the activity decreases. Therefore, the temperature of the Kl1 degree regulator (8) or the catalyst (9) is constantly monitored, and the flow rate of combustible gas (I) and oxidizing gas are zero.
) is necessary to adjust the flow rate accordingly.

In addition, in the above embodiment, the flammable gas (to) supplied to the temperature controller (8) during heating operation is shown to be supplied from outside separately in Fig. 2, but in the fuel cell power generation system, the combustible gas is supplied separately from the outside. It would be even better if it could be used. Specifically, in FIG. 2, for example, unused fuel exhaust gas may be used in the fuel cell device (1).

In addition, especially for molten carbonate fuel cells, high-temperature W
At A (for example, 450° C. or higher), it is necessary to hold in an atmosphere containing carbon dioxide to avoid decomposition of the electrolyte. Therefore, the amount of combustible gas supplied to the temperature controller (8) is hydrocarbons or alcohols containing carbon atoms, and carbon dioxide contained in the combustion exhaust gas discharged from the temperature controller (8) is used. If it is supplied to the gas flow path as the atmospheric gas of the fuel cell (5), efficient heating can be achieved. This can be easily achieved, for example, by introducing combustion exhaust gas (G) into the oxidizing gas flow path.

Further, FIG. 3 shows the configuration of a fuel cell power generation system to which a fuel cell device according to another embodiment of the present invention is applied.

In the figure, (13a) and (13b) are pulp,
When the temperature regulator (80) is in heating operation, the pulp (13a) is opened and the pulp (13b) is closed, and the combustion exhaust gas (G) is circulated to the outside of the fuel cell device (IJ) in the same manner as in the above embodiment.

On the other hand, during the cooling operation, the pulp (13a) is opened and the pulp (13b) is opened. A fertile hydrocarbon or a alcohol such as methanol is introduced as a fluid into the temperature controller (8), and an endothermic reaction, for example a reforming reaction, proceeds with the help of the catalyst (9) according to the following formula, and the endothermic reaction at that time is It operates as a cooler by removing reaction heat from the fuel cell stack (6).

2n+m CnHm+nHzO-ncO+() H2-(1) Alcohol + H20-Go, CO2, H2...(2) Alcohol -〇〇, COz, Hz...
(3) CO+H20gacO2+Hz
...(4) CH4-[20miCO+3EIz
...(5) In general, the heat of endothermic reaction due to the reforming reaction is 1% compared to the amount of cooling heat due to sensible heat when gas is used as the heat medium and the temperature difference between the inlet and outlet is set to 100°C, for example.
It is about 00 to 300 times larger and can perform effective cooling with a small amount of gas. Therefore, compared to a power generation system using a conventional fuel cell device, the loss of auxiliary equipment for cooling gas circulation can be greatly reduced, and the circulation of the reaction gas that was circulated to cool the fuel cell device (1) can be reduced significantly. The amount of unnecessary circulation can be reduced, the amount of evaporation loss of electrolyte is reduced, and the life of the fuel cell can be extended.

It is preferable that the catalyst (9) according to this embodiment is one that promotes both the catalytic combustion reaction and the reforming reaction.

As such a catalyst (9), a catalyst commercially available as a catalyst for normal catalytic combustion or a catalyst for a reforming reaction of alcohols can be used. Specifically, for example, alumina,
Pt, porous materials made of inorganic materials such as magnesia,
At least one of R11, P(1, Rd, etc.) is supported in an amount of about 0.1 to 1.0%.

In order to promote the reforming reaction of hydrocarbons during cooling operation, it is necessary that the metal supported on the porous material of the catalyst (9) be in a reduced state. It is desirable to perform the reduction process (9). On the other hand, especially at high temperatures (e.g. 300℃),
The above) is known to proceed easily, and since the catalyst (9) can be automatically reduced with the hydrogen generated by its own decomposition, no special reduction treatment is necessary.

In addition, in this embodiment, when the fuel cell device (υ) is in steady operation (during power generation), that is, when the temperature controller (8) is in cooling operation, hydrogen discharged from the temperature controller (8) is used as the main component. The reformed gas is passed through the pulp (13b) and directly into the fuel gas flow path (lb) of the fuel cell (4).
It is supplied as. By doing so, efficient use of the reformed gas, that is, effective use of energy can be achieved. In addition, in such a system configuration, approximately V3 of the heat generated in the fuel cell is usually removed via the temperature controller (3), and the remaining heat is removed by other cooling means, such as a portion of the oxidizing gas. Remove by circulation.

In the above embodiments, a general fuel cell that directly uses hydrogen as fuel has been described, but in some cases, a reforming catalyst such as N1 may be installed in the fuel gas flow path (lb). However, an internal reforming type fuel cell may be used in which the reforming reaction can proceed in parallel with the electrode reaction. in this case,
A greater effect can be obtained when hydrocarbons or alcohols can be used directly as fuel. For example, in FIG. 3, a case will be specifically described in which an internal reforming type fuel cell is used.

Due to equilibrium constraints in the temperature ζ unit (8), methane is discharged undecomposed, and the deviation from chemical equilibrium is caused by the action of steam generated or consumed hydrogen in the fuel gas flow path (lb). arise. Due to the action of the reforming catalyst provided in the fuel gas flow path (1b), undecomposed methane is almost completely decomposed and utilized for the electrode reaction.For example, if the fuel gas is natural gas and the fuel cell is molten carbonate In the case of a system using a conventional fuel cell (operating at 600 to 700 degrees Celsius), for example, 1 to 1,596 tons of methane out of the input fuel gas is discharged from the fuel cell device (1) undecomposed and unused. However, when using an internal reforming type fuel cell, the methane decomposition rate is 9
Proceed by more than 9%. Therefore, using an internal reforming type fuel cell enables a higher fuel utilization rate than K, improves the cell characteristics, and greatly improves the power generation efficiency of the system. In addition, in the above embodiment, the catalyst (9) has the function of first promoting the catalytic combustion reaction and the reforming reaction, but the catalyst (9) having each function is They may be provided in the temperature controller (8) or may be provided in a mixed manner.

In short, the generally used temperature regulator (8) in the fuel cell device (1) according to this embodiment has both the function of promoting catalytic combustion and the function of promoting reforming reaction.

Furthermore, the endothermic reaction during the cooling operation is not limited to the reforming reaction, and other endothermic reactions may be used.

Further, in the above embodiment, a case is described in which one Ifi & regulator (8) is provided adjacent to the fuel cell stack (6)K, but a plurality of temperature regulators (8) may be provided as necessary. It's okay.

[Effect of the Invention J As described above, according to the present invention, the fuel gas is supplied from the fuel gas flow path to the fuel gas electrode, and the oxidizing gas is supplied to the oxidation gas electrode from the oxidation gas flow path, thereby causing an electrochemical reaction. A fuel cell laminate in which one or more fuel cells are stacked,
A temperature regulator is provided adjacent to the fuel cell stack, and has a fluid circulation path and a catalyst in the circulation path. By supplying combustible gas and oxidizing gas to the temperature regulator and catalytically burning the fuel, Equipped with a heating means for heating the battery stack and a cooling means for cooling the fuel cell stack by circulating a cooling heat medium through the temperature controller, the startup time is short and heating with high thermal efficiency is achieved. This has the effect of providing a fuel cell device in which the temperature #J can be controlled relatively easily.

According to another aspect of the present invention, fuel gas is supplied from the fuel gas flow path to the fuel gas electrode,
A fuel cell stack in which one or more fuel cells are stacked, in which oxidizing gas is supplied from an oxidizing gas flow path to an oxidizing gas electrode to cause an electrochemical reaction; A temperature regulator that has a catalyst in this circulation path, a heating means that heats the fuel cell stack by supplying combustible gas and oxidizing gas to the temperature regulator for catalytic combustion, and supplying fluid to the temperature regulator. By providing a cooling means for cooling the fuel cell stack, the fuel cell can be heated and cooled efficiently using the amount of gas circulated in the device. This has the effect of reducing auxiliary equipment loss, and further reducing electrolyte loss from the fuel cell, resulting in a long-life fuel cell device.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway side view of a fuel cell device according to an embodiment of the present invention, FIG. 2 is a block diagram showing a fuel cell power generation system using a fuel cell device according to an embodiment of the present invention, and FIG. FIG. 3 is a block diagram showing a fuel cell power generation system using a fuel cell device according to an embodiment of the present invention, and FIG. 4 is a block diagram showing a fuel cell power generation system using a conventional fuel cell device. (1) Fuel cell device, (tb) Fuel gas flow path, (lc) Oxidizing gas flow path, (5) Fuel cell, (6) Fuel cell stack body, (8)...temperature regulator, (9)...catalyst. In addition, in FIG. 1, the same reference numerals indicate the same or equivalent parts.

Claims (11)

[Claims] (1) A fuel cell stack in which one or more fuel cells are stacked in which fuel gas is supplied to the fuel gas electrode from the fuel gas flow path and oxidizing gas is supplied to the oxidizing gas electrode from the oxidizing gas flow path to cause an electrochemical reaction. , a temperature regulator that is provided adjacent to the fuel cell stack and has a fluid circulation path and a catalyst in the circulation path, and a flammable gas and an oxidizing gas are supplied to the temperature regulator for catalytic combustion. A fuel cell device comprising: a heating means for heating the fuel cell stack; and a cooling means for cooling the fuel cell stack by circulating a cooling heat medium through the temperature regulator. (2) The catalyst contains Pt, Ru, Pd, and R in the porous material.
2. The fuel cell device according to claim 1, wherein the fuel cell device supports at least one of the following. (3) Claim 1 or 2, characterized in that the cooling heat medium is an oxidizing gas used for catalytic combustion.
The fuel cell device described in Section 1. (4) The fuel cell device according to claim 1 or 2, wherein the cooling heat medium is an inert gas. (5) The temperature controller has a first inlet for introducing a flammable gas, a second inlet for introducing an oxidizing gas, and an outlet for leading out an internal fluid. The fuel cell device according to any one of the ranges 1 to 4. (6) A fuel cell stack in which one or more fuel cells are stacked, in which fuel gas is supplied to the fuel gas electrode from the fuel gas flow path, and oxidizing gas is supplied to the oxidizing gas electrode from the oxidizing gas flow path to cause an electrochemical reaction. , a temperature regulator that is provided adjacent to the fuel cell stack and has a fluid circulation path and a catalyst in the circulation path, and a flammable gas and an oxidizing gas are supplied to the temperature regulator for catalytic combustion. , a fuel cell device comprising a heating means for heating the fuel cell stack, and a cooling means for cooling the fuel cell stack by supplying a fluid to the temperature regulator to cause an endothermic reaction. (7) The fuel cell device according to claim 6, wherein the cooling means supplies hydrocarbons or alcohols to the temperature controller to cause a reforming reaction. (8) A claim characterized in that a gas whose main component is hydrogen reformed by a reforming reaction of a temperature controller is supplied to a fuel gas electrode of a fuel cell stack. The fuel cell device according to item 7. (9) The fuel cell device according to claim 8, wherein the fuel gas flow path has a reforming catalyst for reforming hydrocarbons or alcohols contained in the fuel gas. (10) The catalyst provided in the circulation path of the temperature regulator is a porous material supporting at least one of Pt, Ru, Pd, and Rd. The fuel cell device according to any one of Items 6 to 9. (11) The fuel cell device according to claim 7, wherein the alcohol is methanol.