JPH0992319A - Carbon monoxide transformer for fuel cell power generating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a carbon monoxide transformer for fuel cell power generating device in which the setting of an electric heater is dispensed with. SOLUTION: A fuel cell power generating device 1 uses a carbon monoxide transformer 2 and a valve 11, to a conventional fuel cell generating device. The carbon monoxide transformer 2 is not provided with an electric heater for heating the catalyst layer, and both the heating of the catalyst layer in the starting the carbon monoxide transformer 2 and the heat elimination from the catalyst layer in the operation of the carbon monoxide transformer 2 are performed by a cooler (cooling pipe) 61 to which a heat medium (cooling water) 91 is passed.

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 generator for removing carbon monoxide as an impurity from a hydrogen-rich reformed gas obtained by reforming a hydrocarbon-based raw fuel by a reformer. The present invention relates to a carbon monoxide transformer for use in a vehicle, and relates to an improved structure of the carbon monoxide transformer for simplification of structure.

[0002]

2. Description of the Related Art A fuel cell power generator is a power generator that generates direct current power by utilizing hydrogen and oxygen. It is expected to be a so-called clean energy source because of its high conversion efficiency and its low emission of atmospheric pollutants such as carbon dioxide and nitrogen oxides.
In many cases, in a phosphoric acid fuel cell power generation device, phosphoric acid is used as the electrolyte, and hydrogen obtained by steam reforming a hydrocarbon-based raw fuel such as natural gas or naphtha as the fuel gas. The fuel gas obtained by removing carbon monoxide from the rich reformed gas is used as the oxidant gas, and the air supplied by the air supply device is used. In this phosphoric acid fuel cell power generator, a unit cell is composed of a matrix supporting phosphoric acid and a pair of fuel electrode and oxidant electrode sandwiching the matrix.

The fuel electrode and the oxidant electrode are porous gas diffusion electrodes through which the fuel gas and the oxidant gas can pass. These unit cells include, for example, a cooling body interposed every time a plurality of layers are stacked, and a plurality of stacked bodies including the plurality of unit cells and the cooling body are stacked to form a fuel cell main body. The fuel gas and the oxidant gas are supplied to cause an electrochemical reaction to generate direct current electricity from the both electrodes. Further, in order to operate the phosphoric acid type fuel cell power generator with high efficiency, it is desirable to operate while maintaining the temperature of the unit cell at about 200 [° C.]. There is known a water-cooled device in which pure water, for example, is supplied as cooling water to a cooling body to remove heat from a unit cell due to a loss generated during an electrochemical reaction.

By the way, the hydrogen-rich reformed gas obtained by steam reforming a hydrocarbon-based raw fuel such as natural gas or naphtha contains a high concentration of carbon monoxide. It is general. Since this carbon monoxide is a poisoning substance for the electrode catalyst of the phosphoric acid type fuel cell main body, it is essential to remove carbon monoxide from the reformed gas. It is a carbon monoxide transformer.

A carbon monoxide transformer according to a conventional example will be described below with reference to FIG. 3 together with the main part of a phosphoric acid type fuel cell power generator. Here, FIG. 3 is a process flow diagram for explaining the carbon monoxide shift converter of the conventional example together with the main part of the fuel cell power generator. In FIG. 3, reference numeral 9 is a water-cooled phosphoric acid type fuel cell body 8, a fuel reformer 7, a carbon monoxide shift converter 6, a steam separator 5 as a cooling water supply device, and an oxidizer. It is a fuel cell power generation device including an air blower 93 that is a supply device. The fuel reformer 7 is a device that reforms a hydrocarbon-based raw fuel 94 such as natural gas or naphtha into a hydrogen-rich reformed gas 7a, and a reforming catalyst pipe (not shown) filled with a reforming catalyst. And a burner not explicitly shown. The reforming catalyst tube has a temperature suitable for reforming the raw fuel 94,
For example, in the case of natural gas, it is necessary to heat it to about 600 to 800 [° C.], and the burner normally burns the exhaust fuel gas (hereinafter abbreviated as off gas) 8a that has already reacted in the fuel cell body 8. Then, a high-temperature gas body used for heating the reforming catalyst tube is generated. The carbon monoxide shifter 6 transforms the carbon monoxide in the reformed gas 7a into a substance harmless to the electrode catalyst of the fuel cell body 8 to sufficiently reduce the carbon monoxide concentration. Is supplied to the fuel cell body 8.

As described above, the fuel cell body 8 includes a pair of fuel electrode 81 and oxidant electrode 82 sandwiching a matrix.
Although it is a laminated body of a plurality of unit cells having a and a plurality of cooling bodies 83, it is schematically shown in FIG.
The fuel gas 6a is supplied to the fuel electrode 81, and the reaction air 93a is supplied to the oxidant electrode 82. The fuel gas 6a is used together with the reaction air 93a for power generation by an electrochemical reaction in the fuel cell body 8, consumes hydrogen and becomes the off gas 8a, and is discharged from the fuel cell body 8.
However, since hydrogen still remains in the offgas 8a, it is supplied to the burner of the fuel reformer 7 and the air 9 for burner is supplied.
It is burnt with 3b and is used to heat the reforming catalyst tube to the required temperature. The reaction air 93a and the burner air 93b are supplied from the air blower 93. The reaction air 93a is discharged from the fuel cell main body 8 after being used for power generation by the oxidizer electrode 82, and joins with the exhaust gas (not shown) discharged from the fuel reformer 7 to generate heat when necessary. Is collected and then discharged to the outside of the fuel cell power generator 9.

When direct current power generation is performed in the fuel cell main body 8 by an electrochemical reaction, heat loss is generated which is substantially proportional to the value of the output current, and this heat loss is inserted in each unit cell. The cooling water 91 is passed through the cooling body 83 and removed by pressure boiling cooling. This cooling water 91 is given a pressure required to circulate in the circulation path by a pump (not shown) and is supplied to the cooling body 83 of the fuel cell main body 8. Cooling water 91 that has taken heat from the unit cell in the cooling body 83
Is removed by a heat exchanger (not shown), passes through the steam separator 5, and is then supplied again to the cooling body 83 of the fuel cell main body 8.

The water vapor separator 5 is composed of a pressure vessel, and separates water vapor from the cooling water 91 which has lost heat from the cooling body 83 by pressure boiling cooling, and temporarily stores the cooling water 91 from which the water vapor has been separated. It also serves to adjust the temperature of the cooling water 91 by adjusting the steam pressure value. The steam (not shown) obtained by the steam separator 5 is used as steam for adding to the raw fuel 94 for steam reforming. The electric heater 51 included in the water vapor separator 5 is, for example, a sheathed heater, and is operated when the fuel cell main body 8 at the time of starting the fuel cell power generator 9 is still low temperature to cool the cooling water 91 to about 160 [° C.]. It is used to heat up. Thus, the cooling water 91 supplied from the water vapor separator 5 is always pressurized water having a temperature of about 160 [° C.]. In addition, the steam separator 5 has a reformed gas 7a.
Since the fuel gas 6a does not exist, the electric heater 51
Is different from the electric heater 62, which will be described later, in the steam separator 5
In mounting the device on the air conditioner, it is not necessary to take measures to prevent the reformed gas 7a and the fuel gas 6a from leaking out.

The carbon monoxide shift converter 6 includes a metal container (not shown), a shift catalyst layer (not shown) formed by filling the container with a granular shift catalyst, and a cooling pipe 61 as a cooler. , A device having an electric heater 62,
In FIG. 3, it is schematically shown. In this case, the granular conversion catalyst is a catalyst that performs a conversion reaction for converting carbon monoxide into hydrogen and carbon dioxide at a reaction temperature of about 200 to 300 [° C.] and in the presence of water vapor. Since the reaction carried out by the granular conversion catalyst is an exothermic reaction as is well known, the temperature of the catalyst layer is set to an appropriate value.
In order to maintain the reaction temperature of about 00 to 300 [° C.], some cooling is required. The cooling pipe 61 plays this role, and a part of the cooling water 91 is branched and supplied to the cooling pipe 61 through the valve 92 when the fuel cell power generator 9 is operating. This valve 92 is opened when the fuel cell power generator 9 is operating, and when the fuel cell power generator 9 is started, that is, when the carbon monoxide transformer 6 is started.
It is closed.

Further, the shift conversion catalyst has a temperature of 160 ° C. to 180 ° C.
Since the catalyst has an activity at about [° C.] or higher, when the carbon monoxide shift converter 6 is started, the catalyst layer is set at 160 [° C.] to
It is necessary to heat above 180 [° C],
The electric heater 62 plays this role. The electric heater 62 is composed of a plurality of sheathed heaters. These sheathed heaters are attached to the carbon monoxide shift converter 6 so as to penetrate through the metal container thereof, and efficiently heat the catalyst layer. Therefore, the heat generating portion is deeply inserted into the catalyst layer. Then, the penetration portions of these sheathed heaters to the metal container are the reformed gas 7 containing hydrogen from this portion.
Since it is necessary to reliably prevent the leakage of fuel a and fuel gas 6a,
It is hermetically sealed by a metal container and welding method.

[0011]

The carbon monoxide shifter according to the prior art described above, for example, the carbon monoxide shifter 6 is configured as described above in the fuel cell power generator 9, and the reformed gas 7a is Since the carbon monoxide is converted into the fuel gas 6a having a sufficiently low concentration, the power generation performance of the fuel cell body 8 can be maintained for a long time. However, the conventional carbon monoxide transformer 6 has the following problems. That is, the electric heater 62 included in the carbon monoxide transformer 6 needs to be hermetically sealed as described above when mounted on the carbon monoxide transformer 6, and in order to maintain this hermeticity for a long time, The sealing needs to be done by the welding method. For this reason, the construction work is complicated, and the manufacturing cost of the carbon monoxide transformer 6 is increased. Further, when the electric heater 62 is disconnected, it is necessary to replace the electric heater 62. However, when replacing the electric heater 62 mounted on the carbon monoxide shift converter 6 by the welding method, the welded portion is replaced. It is necessary to remove the damaged product and then mount the new product again by the welding method. When it is necessary to perform such work on the site where the fuel cell power generator 9 is installed, it takes a long working time because there are many constraint conditions for performing the work on the site. Therefore, the operation stop time of the fuel cell power generator 9 is to be lengthened.

The present invention has been made in view of the above-mentioned problems of the prior art, and an object thereof is to provide a carbon monoxide transformer for a fuel cell power generator which does not require installation of an electric heater. is there.

[0013]

In the present invention, the above-mentioned objects are included in: 1) a reformer for reforming a hydrocarbon-based raw fuel to produce a hydrogen-rich reformed gas, and the reformed gas. A carbon monoxide shifter that removes carbon monoxide and refines it into fuel gas, and an electrochemical power generation using this fuel gas and the oxidant gas supplied by the oxidant supply device as reaction gas A fuel cell power generator including a fuel cell main body having a cooling body for circulating and removing generated heat and cooling water, and a cooling water supply device for supplying cooling water of a desired temperature to the cooling body. A carbon monoxide shift converter used, comprising a catalyst layer filled with a granular catalyst for removing carbon monoxide contained in a reformed gas, a metal container having the catalyst layer housed therein, and a catalyst layer. With a cooler to maintain the desired temperature In a carbon monoxide shifter for a fuel cell power generation device having: a carbon monoxide shifter, cooling water supplied from a cooling water supply device is used as a heat medium applied to the cooler from outside. It is achieved by the configuration.

Thus, the same cooler is used as a means for heating the catalyst layer when the carbon monoxide shift converter is started and for removing heat from the catalyst layer when the carbon monoxide shift converter is operating. As the heat medium supplied to this cooler, the cooling water of about 160 [° C.] which is constantly supplied by the cooling water supply device is used both when the carbon monoxide shift converter is started and when it is operated. As a result, the catalyst layer is heated to approximately 160 [° C.] when the carbon monoxide shift converter is started, and is maintained at the same temperature as in the prior art during operation, so that carbon monoxide from the reformed gas is removed. It can be removed without any trouble. 2) In the means described in 1) above, the fuel cell power generation device includes a heating device that heats a part of the cooling water supplied from the cooling water supply device, and the carbon monoxide shift converter is externally provided. The cooling medium supplied from the cooling water supply device via the heating device is used as the heat medium supplied to the cooler.

As a means for heating the catalyst layer at the time of starting the carbon monoxide shift converter and removing the heat of the catalyst layer at the time of operating the carbon monoxide shift converter, the same cooler as in the above item 1 is used. Is used. As the heat medium supplied to this cooler, when starting the carbon monoxide shift converter, the cooling water of about 160 [° C.] which is constantly supplied by the cooling water supply device is supplied by the heating device to, for example, 180 [° C.]. ℃] is used after heating. As a result, the catalyst layer is heated to approximately 180 ° C. when the carbon monoxide shift converter is started.

When the carbon monoxide shift converter is in operation, the fuel supply of the cooling water by the heating device is stopped, and the cooling water supply device constantly supplies the heat medium supplied to the cooler 160. Cooling water of about [° C.] is used at the same temperature. As a result, the catalyst layer is maintained at the same temperature as in the case of the conventional technique during the operation of the carbon monoxide shift converter. From the above, it is possible to remove carbon monoxide from the reformed gas without any trouble.

[0017]

Embodiments of the present invention will be described below in detail with reference to the drawings. In the following description, the conventional carbon monoxide transformer shown in FIG. 3 and
The same parts as those of the main part of the fuel cell power generator are designated by the same reference numerals and the description thereof will be omitted. It should be noted that, in FIGS. 1 and 2, only the representative reference numerals are shown for the reference numerals given in FIG.

Embodiment 1 FIG. 1 is a process flow diagram for explaining a carbon monoxide transformer according to an embodiment of the present invention corresponding to claim 1 together with the main part of a fuel cell power generator. In FIG. 1, reference numeral 1 replaces the carbon monoxide shifter 6 and the valve 92 in the fuel cell power generator 9 according to the conventional example shown in FIG. 3, and uses a carbon monoxide shifter 2 and a valve 11, respectively. This is a phosphoric acid type fuel cell power generator. In the carbon monoxide shift converter 2, the electric heater 62 is not installed in the conventional carbon monoxide shift converter 6. Further, unlike the valve 92 according to the conventional example, the valve 11 is in a normal state regardless of whether the fuel cell power generator 1 is started or operated, and thus the carbon monoxide shift converter 2 is not started or operated. It is always open.

Since the above-mentioned configuration is adopted in the first embodiment, in the carbon monoxide shift converter 2, the heating of the catalyst layer at the time of its startup and the heat removal from the catalyst layer at the time of its operation are
It is performed by a cooling pipe 61 which is a cooler. Cooling pipe 61
The cooling water 91 of about 160 [° C.] which is constantly supplied from the water vapor separator 5 flows through as a heat medium given from the outside, so that the above heating and heat removal can be performed without any trouble. As a result, the carbon monoxide transformer 2 according to the present invention is different from the conventional carbon monoxide transformer 6 in that
The electric heater 62 need not be installed. Therefore, the carbon monoxide transformer 2 can completely eliminate the complicated construction work involved in the installation of the electric heater 62 and the work involved in defective replacement of the electric heater 62.

Embodiment 2 FIG. 2 is a process flow diagram for explaining a carbon monoxide transformer according to an embodiment of the present invention corresponding to claims 1 and 2 together with a main part of a fuel cell power generator. 2, a carbon monoxide transformer according to an embodiment of the present invention corresponding to claim 1 shown in FIG. 1, and
The same parts as those of the fuel cell power generator are designated by the same reference numerals and the description thereof is omitted. It should be noted that in FIG. 2, a part of the devices constituting the fuel cell power generation device shown in FIG. 1 is omitted.

In FIG. 2, 3 is a phosphoric acid type fuel cell power generator in which a heating device 4 is provided in addition to the fuel cell power generator 1 according to the present invention shown in FIG. The heating device 4 is supplied with a fuel (not shown) (for example, the raw fuel 94) to heat the heating medium 4a.
And using the heating medium 4a heated by the boiler 41 as a heat source,
The heat exchanger 42 heats the cooling water 91 supplied to the carbon monoxide shift converter 2. Then, this heating device 4
Is, in principle, operated only when the fuel cell power generator 3 is started, and thus when the carbon monoxide transformer 2 is started,
The cooling water 91 flowing through the heat exchanger 42 is, for example, 180
Heat above [° C]. The cooling water 91 flows through the heat exchanger 42 even when the heating device 4 is not operated, but in this case, its temperature is not changed.

Since the second embodiment has the above-described configuration, when the carbon monoxide shift converter 2 is started, the temperature of the cooling water 91 supplied to the carbon monoxide shift converter 2 is set higher than the temperature during the operation. be able to. As a result, even if the shift conversion catalyst used in the carbon monoxide shift converter 2 is a catalyst that is active at a temperature higher than the temperature of the cooling water 91, for example, about 180 [° C.] or higher, carbon shift conversion is performed. Bowl 2
It is possible to heat the catalyst layer to a suitable temperature at the time of starting. Thus, in spite of this, the same action and effect as in the case of the first embodiment can be obtained.

In the above description of the second embodiment, the heating means for the heating medium 4a provided in the heating device 4 is the boiler 41 using fuel, but the heating means 4 is not limited to this. For example, an electric heater. May be

[0024]

According to the present invention, the following effects can be obtained by adopting the structure described in the section for solving the above-mentioned problems. By adopting the configuration according to the first item of the means for solving the problem, it is not necessary to install an electric heater in the carbon monoxide transformer. As a result, the complicated construction work associated with the installation of the electric heater is eliminated, so that the manufacturing cost of the carbon monoxide transformer is reduced. At the same time, it becomes possible to solve the problem of suspending the operation of the fuel cell power generator for a long time when the defective electric heater is replaced locally.

With the configuration according to the second item of the means for solving the problem, the heat medium (cooling water supplied from the cooling water supply device) to be supplied to the carbon monoxide shift converter is Even if the temperature is lower than the temperature at which the shift catalyst used in the carbon monoxide shift converter is activated,
It is possible to start the carbon monoxide transformer without any trouble, and it is possible to obtain the effect of the above item.

[Brief description of drawings]

FIG. 1 is a process flow chart for explaining a carbon monoxide shifter according to an embodiment of the present invention corresponding to claim 1 together with a main part of a fuel cell power generator.

FIG. 2 is a process flow diagram for explaining a carbon monoxide transformer according to an embodiment of the present invention corresponding to claims 1 and 2 together with a main part of a fuel cell power generator.

FIG. 3 is a process flow diagram for explaining a conventional carbon monoxide transformer together with a main part of a fuel cell power generator.

[Explanation of symbols]

 1 Fuel Cell Power Generation Device 11 Valve 2 Carbon Monoxide Transformer 61 Cooler (Cooling Pipe) 91 Heat Medium (Cooling Water)

Claims (2)

[Claims] 1. A reformer for reforming a hydrocarbon-based raw fuel to produce a hydrogen-rich reformed gas, and a monoxide for removing carbon monoxide contained in the reformed gas to purify it into a fuel gas. In order to electrochemically generate electricity using the carbon shifter and the oxidant gas supplied by this fuel gas and oxidant supply device as reaction gas, and to circulate the cooling water to remove the heat generated during power generation. A carbon monoxide shifter used in a fuel cell power generator including a fuel cell main body having a cooling body, and a cooling water supply device for supplying cooling water of a desired temperature to the cooling body, the reformed gas A fuel having a catalyst layer filled with a granular catalyst for removing carbon monoxide contained in, a metal container containing the catalyst layer therein, and a cooler for keeping the catalyst layer at a desired temperature. For carbon monoxide transformer for battery power generator The carbon monoxide transformer is characterized in that the cooling water supplied from the cooling water supply device is used as the heat medium supplied to the cooler from the outside thereof. Carbon transformer. 2. The carbon monoxide transformer for a fuel cell power generator according to claim 1, wherein the fuel cell power generator comprises a heating device for heating a part of the cooling water supplied from the cooling water supply device. The carbon monoxide transformer is used as a heat medium from the outside to the cooler.
A carbon monoxide transformer for a fuel cell power generator, wherein cooling water supplied from a cooling water supply device through a heating device is used.