JPH01143156A - fuel cell power generator - Google Patents

Abstract

PURPOSE:To use no hydrogen for desulfurization during the normal operation from the start by providing only multiple desulfurizers using activated carbon as a desulfurizing agent and making adequate number of them regenerative type desulfurizers. CONSTITUTION:Multiple desulfurizers 19 and 20 using activated carbon are provided on a line 4 guiding the ordinary-temperature gas containing a sulfur content to a reformer 5 as fuel, desulfurization is performed by the desulfurizers 19 and 20 during the normal operation after the start. When a power generator is started, desulfurization is performed by one desulfurizer 19 (20) of the multiple desulfurizers 19 and 20, subsequently desulfurization is performed by the other desulfurizer 20 (19) as appropriate, the activated carbon of one desulfurizer 19 (20) is regenerated during that time, they are switched in sequence, and desulfurization is performed by the desulfurizers using the activated carbon even during the normal operation. No hydrogen is thereby required at the time of a start and during the normal operation.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention is particularly applicable to power generation using fuel cells that require desulfurization among fuel cells used in the energy sector that directly converts the chemical energy of fuel into electrical energy. It is related to the device.

[Prior art] Among the fuel cells proposed to date, for example,
In a molten carbonate fuel cell, an electrolyte plate (tile) made by impregnating a porous material with molten carbonate as an electrolyte is sandwiched between a cathode (oxygen electrode) and an anode (fuel electrode), and an oxidizing gas is placed on the cathode side. One cell is one in which electricity is generated by the potential difference generated between the cathode and the seven nodes by supplying fuel gas to the anode side, and each cell is laminated in multiple layers with a separator in between. This is the configuration.

In the power generation device using the above molten carbonate fuel cell, it has been proposed to use natural gas, city gas, coal, etc. as the fuel gas. When using city gas as fuel, the city gas is reformed, and when coal is used as fuel, it is gasified and refined.

As a molten carbonate fuel cell power generation system that utilizes a room temperature gas containing sulfur, such as city gas, as the fuel for the molten carbonate fuel cell, a configuration shown in FIG. 2 is known. That is, 1G of city gas to be supplied to the anode 3 of the fuel cell 1 is introduced into the reformer 5 through the line 4, reformed there, and supplied to the anode 3 through the line 6. Line 4 on the entrance side of 5
A desulfurizer 7 using a desulfurization catalyst such as ZnO is installed as a desulfurizer for removing sulfur content in the gas, and natural gas preheaters 8 and 9 are installed above the desulfurizer 7. , the gas discharged from the anode 3 passes through the natural gas preheater 8.9 in order and exchanges heat with the city gas that enters the reformer 5, and then passes through the reformer 5.
The fuel is introduced into the combustion chamber of the engine. In addition, in order to supply oxidizing gas to the cathode 2 of the fuel cell 1, after compressing the air in the compression 4310, the air preheater 11 and the turbine 1 are
2. Cathode 2 via line 14 via air preheater 13
The gas discharged from the cathode 2 is branched and one side is discharged through the air preheater 11. The other is an air preheater 13, a superheater 16,
The water H2 is discharged through the evaporator 17.
0 becomes steam in the evaporator 17, is superheated in the superheater 16, is supplied to the line 4, enters the reformer 5 together with the gas in the line 4, and is discharged from the combustion chamber outlet of the reformer 5. The gas containing carbon dioxide gas is supplied to the cathode 2 together with the gas flowing through the line 14. 18 is a compressor.

[Problems to be Solved by the Invention] However, in the power generation system shown in FIG. From the time when hydrogen is not yet generated in the reformer 5 etc. when the device is started up, the desulfurizer 7
In addition, after hydrogen is generated in the reformer 5 etc., a line 19 is connected to the line 4 upstream of the compressor 18 from the middle of the line 6 connecting the reformer 5 and the anode 3. Since hydrogen is introduced to the side and used in the desulfurizer 7, hydrogen is required for catalyst reduction at startup, but since no hydrogen is generated at startup, a hydrogen cylinder is installed. ■ It takes time and effort to start up due to the catalytic reduction operation that is required at startup; ■ The temperature of the desulfurization tower must be controlled to an appropriate temperature for desulfurization; Since a heat exchanger and a control system are required; ■Hydrogen is required even during normal operation for desulfurization, a portion of the hydrogen to be supplied to the anode 3 of the fuel cell 1 is supplied to the inlet of the desulfurizer 7. There are problems such as having to return the power to the source, which reduces power generation efficiency.

Therefore, in place of the desulfurizer used in the conventional molten carbonate fuel cell power generation device, the present invention aims to eliminate the use of hydrogen for desulfurization from startup to normal operation. It is an attempt to solve various problems.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a fuel cell power generation device that uses a room temperature gas containing sulfur as a fuel to be supplied to the anode of a fuel cell. A plurality of desulfurizers using activated carbon as a desulfurizing agent are installed in the line in which the room temperature gas containing sulfur is introduced into the reformer for reforming, and an appropriate desulfurizer is installed among the desulfurizers. The desulfurizer will be configured as a regenerative type.

[Function] When starting up the power generation device, desulfurization is performed by one desulfurizer out of a plurality of desulfurizers using activated carbon. Thereafter, desulfurization is performed by another desulfurizer as appropriate, while the other desulfurizers regenerate activated carbon, and the desulfurizers are sequentially switched to perform desulfurization using the desulfurizer using activated carbon even during normal operation. This eliminates the need to install a hydrogen cylinder to supply the hydrogen necessary for catalytic reduction as in the conventional method during startup, and also allows some of the hydrogen generated in the reformer to be used for desulfurization during normal operation. It will no longer be used for.

[Example] Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of the present invention, in which, like the conventional city gas reformed molten carbonate fuel cell power generation device shown in FIG. After being reformed in the reformer 5, the gas is supplied to the anode 3 of the fuel cell 1, and the gas discharged from the anode 3 is heat-exchanged with the gas 1G on the way, and then supplied to the combustion chamber of the reformer 5. On the other hand, the air is compressed by a compressor 10,
The turbine 12 expands, preheats and supplies the fuel to the cathode 2 of the fuel cell 1, and a portion of the fuel is introduced into the combustion chamber of the reformer 5 through a branch line 15. In a configuration in which gas containing carbon dioxide discharged from the outlet is supplied to the cathode 2, there is a conventional method in the middle of the line 4 for introducing 1G of room temperature gas containing sulfur into the reformer 5. A desulfurizer is provided in place of the desulfurizer 7. In other words, a plurality of (the figure shows the case of two) UB sulfur evaporators 1920 using activated carbon as a desulfurization agent,
The desulfurizers 19 and 20 are installed in parallel on the inlet side of the compressor 18 in the line 4 so that both desulfurizers 19 and 20 can be used alternately, and the desulfurizers 19 and 20 are connected to the reformer 5. A steam pipe 21 is connected to use a part of the steam to regenerate activated carbon, so that activated carbon can be regenerated as needed.

In the figure, the same parts as shown in FIG. 2 are given the same reference numerals.

In the case where two desulfurizers 19 and 20 are installed as in the above embodiment, when one of the desulfurizers, for example, the desulfurizer 20, is used when starting up the power generation equipment, the desulfurizer used The use of the desulfurizer 19 is stopped, and when the desulfurizer 19 is used, the use of the desulfurizer 20 is also stopped.

Now, when starting up the power generator, the desulfurizer 20 is used to desulfurize the gas TG supplied to the line 4. The use of the desulfurizer 20 is stopped as appropriate and the desulfurizer 19 is used to remove the sulfur content from the gas. During this period, the desulfurizer 20, which has ceased to be used, carries the steam generated in the power generator through the steam pipe 2
The activated carbon is regenerated by introducing the activated carbon through the catalyst.

After the desulfurizer 19 is used for a predetermined period of time, the desulfurizer 19 is stopped and the desulfurizer 20 is used, and the desulfurizer 19 regenerates the activated carbon.

In this way, desulfurization is carried out over a long period of time by using only a desulfurizer using activated carbon.

As a result, the desulfurizer 7, hydrogen extraction line 19, and natural gas preheater 9 in the conventional system can be omitted.

In addition, other desulfurizers may be prepared in addition to the desulfurizers 19 and 20, and three or three or more desulfurizers may be installed in parallel in the middle of the line 4. In this case, one of the desulfurizers is used for desulfurization at startup, and the remaining desulfurizers are used alternately during normal operation, so that when one is in use, the other desulfurizers operate as if they were being regenerated. You can. Further, although the molten carbonate fuel cell 1 is shown as an example, the present invention is not limited thereto.

[Effects of the Invention] As described above, according to the fuel cell power generation device of the present invention,
Multiple desulfurizers using activated carbon are installed in the middle of the line for introducing room-temperature gas containing sulfur into the reformer as fuel (), and the above-mentioned conditions are maintained even after startup and normal operation. Since desulfurization is performed by a desulfurizer and the desulfurizer can be regenerated, there is no need to prepare a hydrogen cylinder like in the past even at startup, and there is no need for catalytic reduction with hydrogen as in the conventional method. Therefore, it does not take time and effort to start up, and there is no need to control the temperature of the desulfurization tower to the appropriate temperature for desulfurization, so equipment such as a heat exchanger can be omitted, and hydrogen is not required even during normal operation. It is possible to achieve excellent effects such as being able to omit a line for extracting hydrogen from the fuel cell and preventing a decrease in power generation efficiency.

[Brief explanation of the drawing]

FIG. 1 is a system configuration diagram showing an embodiment of the present invention, and FIG. 2 is a system configuration diagram of a conventional power generation system. 1... Fuel cell, 2... Cathode, 3... Anode, 4... Line, 5... Reformer, 19.20...
・Desulfurizer, 21...Steam piping.

Claims (1)

[Claims] 1) In a fuel cell power generation device that uses a room-temperature gas containing sulfur as fuel to be supplied to the anode of a fuel cell, the room-temperature gas containing sulfur is introduced into a reformer for reforming. In the middle of the line, multiple desulfurizers that use activated carbon as a desulfurizing agent are installed so that they can be used selectively.
A fuel cell power generation device characterized in that an appropriate desulfurizer is of a regenerative type.