JPH11139803A - Fuel battery power generation system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a power generation system which may be miniaturized and may be operated stably for a long time by desulfurizing raw fuel by a desulfurizer packed with a copper-zinc based desulfurizing agent. SOLUTION: The raw fuel is preferably desulfurized to an S content of <=1 vol.ppb by the desulfurizer and is further desulfurized to <=0.1 vol.ppb. The copper-zinc based desulfurizing agent of the desulfurizer is preferably the desulfurizing agent obtd. by hydrogen reduction of the copper oxide-zinc oxide mixture prepd. by a codeposition method using a copper compd. (e.g.; copper nitrate) and zinc compd. (e.g.; zinc nitrate) or the desulfurizing agent obtd. by hydrogen reduction of the copper oxide-zinc oxide-aluminum oxide mixture prepd. by the codeposition method using the copper compd., the zinc compd. and an aluminum compd. (e.g.; aluminum nitrate). The copper-zinc based desulfurizing agent obtd. in such a manner may preferably contain other components, for example, chromium oxide, etc. Hardly decomposable sulfur compds., such as dimethyl sulfide, may be surely removed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a fuel cell power generation system. More specifically, the present invention relates to a fuel cell power generation system which improves a fuel gas system supplied to a fuel electrode and is particularly suitable for gaseous fuel such as city gas containing an odorant.

[0002]

2. Description of the Related Art Conventionally, a fuel cell is known as a system for directly converting chemical energy of fuel into electric energy. In this fuel cell, a fuel cell is usually formed by opposing a pair of porous electrodes composed of a fuel electrode and an oxidizer electrode with an electrolyte layer holding an electrolyte therebetween, and a fuel gas such as hydrogen is provided on the back of the fuel electrode. And an oxidizing agent such as air is brought into contact with the back surface of the oxidizing agent electrode to take out the electric energy from between the two electrodes by utilizing the electrochemical reaction generated at this time. As long as the fuel gas and the oxidant are supplied, electric energy can be extracted with high conversion efficiency, and it is advantageous for energy saving and environmental protection.

In this type of fuel cell, hydrogen is generally used as a fuel, and this hydrogen is usually methane, ethane,
Raw fuels such as propane, butane, natural gas, naphtha, kerosene, light oil, liquefied petroleum gas (LPG), and city gas are subjected to a steam reforming reaction to be converted into a fuel gas containing hydrogen as a main component. Have been.

[0004] The sulfur component in the raw fuel poisons a steam reforming catalyst (for example, a Ru-based catalyst, a Ni-based catalyst, etc.), for example, when the sulfur content in the raw fuel is about 0.1 ppm. Even in this case, about 90% of the surface of the Ru catalyst or Ni catalyst is covered with sulfur in a short time, and the catalytic activity is significantly deteriorated.
Further, deposition of carbon on the catalyst is observed. Under such circumstances, the raw fuel is subjected to a desulfurization reaction before being subjected to the steam reforming reaction.

[0005] A typical desulfurization method conventionally performed prior to steam reforming of a raw fuel is a Ni-Mo system or a Co-
After hydrocracking organic sulfur in the raw fuel at 350 to 400 ° C. in the presence of a Mo-based catalyst, H ₂ S generated is reduced to 35%.
This is a hydrodesulfurization method in which ZnO is adsorbed and removed at 0 to 400 ° C.

FIG. 2 is a system diagram showing an outline of a basic configuration of a typical example of a fuel cell power generation system having a desulfurization apparatus using a hydrodesulfurization method and a steam reforming apparatus. In FIG. 1, a raw fuel 1 is mixed with a fuel gas containing hydrogen as a main component, which is introduced from a carbon monoxide converter 5, and is introduced into a hydrodesulfurization unit 2b. The hydrodesulfurization unit 2b is used for the raw fuel 1
In order from the inlet side of the substrate, a hydrogen-added layer filled with a Ni-Mo-based or Co-Mo-based catalyst or the like and an adsorption layer filled with an adsorbent such as ZnO. The raw fuel 1 mixed with a part of the fuel gas exiting the carbon monoxide converter 5 is heated to 350 to 400 ° C. by a heater (not shown), and then hydrogenated in a hydrogenation layer to obtain a raw fuel. The sulfur component therein is converted to H ₂ S, and then the generated H ₂ S is adsorbed and removed in the adsorption layer, and the raw fuel 1 is desulfurized. The desulfurized raw fuel 1 is mixed with steam in a mixer 3 and introduced into a steam reformer 4, where it is converted into a fuel gas containing hydrogen as a main component by a steam reforming reaction and discharged. The discharged fuel gas contains carbon monoxide in a carbon monoxide converter 5 filled with a conversion catalyst in order to poison the catalyst of the fuel electrode 7 and to increase the conversion efficiency to hydrogen.
Carbon monoxide is converted to hydrogen and carbon dioxide. Part of the fuel gas discharged from the carbon monoxide converter 5 is sent to the hydrodesulfurization unit 2b, and the rest is sent to the fuel electrode 7 of the fuel cell body 6 to be used as fuel. Hydrogen in the fuel gas flowing into the fuel electrode 7 undergoes an electrochemical reaction with oxygen in the air 9 introduced into the oxidant electrode 10 by the compressor 8, and as a result, a part of the fuel gas is consumed. Electric energy is obtained and water is by-produced.

The fuel gas discharged from the fuel electrode 7 is sent to the burner 11 of the steam reformer 4 and joins with the air 9 supplied by the compressor 8 to form the fuel gas.
The fuel is burned at 1 and used as a heating source of the steam reformer 4. Exhaust gas containing water vapor discharged from the burner 11 passes through a heat exchanger 12 and is then separated into steam and water by a condenser 13, and the separated gas is exhausted. Further, the condensed water merges with the water supply line 14, is sent to the fuel cell main body 6 via the water supply pump 15 and the cooling water pump 16, and is used for cooling the same. The cooling water discharged from the fuel cell body 6 is
After passing through the heat exchanger 17, it is sent to the steam separator 18 where it is separated into water and steam. The separated water is circulated for cooling the fuel cell body 6 through a cooling water pump 16, and steam is sent to the mixer 3 and mixed with the desulfurized raw fuel 1, and then the steam reformed It is sent to 4 and used for a steam reforming reaction.

In such a fuel cell power generation system, there are many problems in the raw fuel desulfurization step. In other words, the hydrodesulfurization catalyst has no catalytic activity unless the temperature is about 350 ° C. or higher, and it is difficult to immediately respond to a change in the load of the fuel cell. A road control device is required, and miniaturization is difficult.

In the case of a raw fuel containing a certain amount or more of organic sulfur in the hydrodesulfurization step, a hardly decomposable and non-adsorbable organic sulfur such as dimethyl sulfide is used as an odorant such as city gas. In the case of a gaseous fuel containing, the undecomposed fuel slips and passes without being adsorbed by ZnO. In the case of adsorption desulfurization, for example,

Embedded image Due to the equilibrium represented by, the amounts of H ₂ S, COS, and the like do not fall below a certain value. This tendency is remarkable especially when H ₂ O and CO ₂ are present. Further, when the desulfurization system is unstable at the start-up or shutdown of the apparatus, sulfur may be scattered from the adsorptive desulfurization catalyst, and the sulfur concentration in the raw fuel may increase. Therefore, in the current desulfurization process, the sulfur concentration in the raw fuel after purification is several ppm or less.
It is carried out at a level of 0.1 ppm, so that poisoning of the steam reforming catalyst or carbon deposition cannot be sufficiently suppressed, and the fuel cell cannot be operated stably for a long time. is there.

[0010]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems of the prior art. By improving the fuel gas system supplied to the fuel electrode, it is possible to reduce the size of the fuel electrode for a long time. An object of the present invention is to provide a fuel cell power generation system that can operate stably.

[0011]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, a fuel cell power generation system according to the present invention is provided with a desulfurization apparatus for desulfurizing a raw fuel, and a fuel mainly containing hydrogen as a desulfurized raw fuel. In a fuel cell power generation system having at least a steam reforming device for reforming into gas, the desulfurization device is characterized by being constituted by a desulfurization device filled with a copper-zinc-based desulfurization agent, particularly as a raw fuel This is a power generation system suitable for a fuel cell that uses gaseous fuel such as city gas. In the present invention, the copper-zinc desulfurizing agent,
Desulfurization that contains at least copper and zinc components (e.g., zinc oxide etc.) and may further contain other components such as aluminum components (e.g., aluminum oxide, etc.) and chromium components (e.g., chromium oxide, etc.) Means the agent.

In the fuel cell power generation system of the present invention, a desulfurizer (hereinafter, referred to as a copper-zinc desulfurizer) filled with a copper-zinc desulfurizer as a desulfurizer is used for desulfurization of the raw fuel. The agent can have a sulfur content in the raw fuel of 1 vol.ppb or less (hereinafter the same as sulfur), usually 0.1 vol.ppb or less. Therefore, poisoning of the steam reforming catalyst in the subsequent steam reforming reaction is suppressed, the catalyst activity can be maintained for a long time, and the fuel cell can be operated stably.

In the present invention having the above structure, the copper-zinc-based desulfurizing agent to be charged into the copper-zinc-based desulfurization apparatus used for the desulfurization of the raw fuel includes, for example, Japanese Patent Application No. 62-27.
No. 9867 and copper-zinc-based desulfurizing agents disclosed in Japanese Patent Application No. 62-279868, which are desulfurizing agents containing copper and zinc oxide as main components (hereinafter referred to as copper-zinc desulfurizing agents). ) And a desulfurizing agent containing copper, zinc oxide and aluminum oxide as main components (hereinafter referred to as copper-zinc-aluminum desulfurizing agent). More specifically, these desulfurizing agents are prepared by the following method.

(1) Copper-zinc desulfurizing agent Copper compound (eg, copper nitrate, copper acetate, etc.) and zinc compound
An aqueous solution containing (eg, zinc nitrate, zinc acetate, etc.) and an aqueous solution of an alkali substance (eg, sodium carbonate, etc.) are used to cause precipitation by a common coprecipitation method. The resulting precipitate is dried and calcined (about 300 ° C.) to form a copper oxide-zinc oxide mixture (generally, copper: zinc = 1: about 0.3 to 1).
0, preferably 1: about 0.5 to 3, more preferably 1: about 1 to 2.3), and then a hydrogen content of 6% by volume or less, more preferably about 0.5 to 4% by volume. The mixture is reduced at about 150 to 300 ° C. in the presence of hydrogen gas diluted with an inert gas (for example, nitrogen gas or the like). The copper-zinc desulfurizing agent thus obtained may contain other components, for example, chromium oxide.

(2) Copper-zinc-aluminum desulfurizing agent Copper compound (eg, copper nitrate, copper acetate, etc.), zinc compound (eg, zinc nitrate, zinc acetate, etc.) and aluminum compound
(For example, aluminum nitrate, sodium aluminate, etc.)
And an aqueous solution of an alkaline substance (for example, sodium carbonate, etc.) containing water and an aqueous solution of an alkaline substance to cause precipitation. The formed precipitate is dried and calcined (about 300 ° C.) to obtain a copper oxide-zinc oxide-aluminum oxide mixture.
(Atomic ratio, usually copper: zinc: aluminum = 1: about 0.3
-10: about 0.05-2, preferably 1: about 0.6-3:
After obtaining about 0.3 to 1), hydrogen diluted with an inert gas (for example, nitrogen gas or the like) so as to have a hydrogen content of 6% by volume or less, more preferably about 0.5 to 4% by volume. The mixture is reduced at about 150 to 300 ° C. in the presence of a gas. The copper-zinc-aluminum desulfurizing agent thus obtained may contain other components such as chromium oxide.

The copper-zinc-based desulfurizing agent obtained by the methods (1) and (2) is characterized in that fine-particle copper having a large surface area is
It is uniformly dispersed in zinc oxide (and aluminum oxide) and is in a highly active state due to chemical interaction with zinc oxide (and aluminum oxide). Therefore,
When these desulfurizing agents are used, the sulfur content in the raw fuel can be reliably reduced to 1 vol. Ppb or less, usually 0.1 vol. Ppb or less. In addition, hardly decomposable sulfur compounds such as dimethyl sulfide can be reliably reduced. Can be removed.

In the present invention, as the raw fuel used, various fuels conventionally used as raw fuels for fuel cells can be used. Particularly, gaseous fuels are preferable. For example, methane, ethane, propane, Butane, natural gas,
LPG, city gas, and mixtures thereof, and the like.
Further, as the oxidant supplied to the oxidant electrode, for example,
Examples include oxygen, air, compressed air, oxygen-enriched air, and the like.
The type of fuel cell to which the present invention is applied is not particularly limited,
Any of low-temperature fuel cells (for example, phosphoric acid electrolyte fuel cells, solid polymer electrolyte fuel cells, super strong acid electrolyte fuel cells, etc.) and high-temperature fuel cells (for example, molten carbonate fuel cells, solid oxide electrolyte fuel cells, etc.) It may be.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the accompanying drawings showing embodiments. FIG. 1 is a system diagram showing an outline of an embodiment of the fuel cell power generation system of the present invention, and the same members as those in FIG. 2 are denoted by the same reference numerals.

In FIG. 1, after the raw fuel 1 is preheated by a heater or a heat exchanger provided separately as required,
It flows into the copper-zinc system desulfurizer 2a. The copper-zinc desulfurizer 2a is filled with the above-mentioned copper-zinc desulfurizer, and the desulfurization in the desulfurizer 2a is performed, for example, at a temperature of 10 to 10.
About 400 ° C, preferably about 150 to 250 ° C, pressure about 0 to 10 kg / cm ² · G, GHSV 500 to 5000
However, the present invention is not limited to this condition. The raw fuel 1 discharged from the desulfurizer 2a is desulfurized to have a sulfur content of 1 vol. Ppb or less, usually 0.1 vol. Ppb or less.

The raw fuel 1 thus desulfurized is mixed with steam at an appropriate mixing ratio in a mixer 3 and then introduced into a steam reformer 4 where it is subjected to a steam reforming reaction to contain hydrogen as a main component. Is converted into a fuel gas. The steam reformer 4 is, for example, Ru, similar to a steam reformer of a conventional fuel cell.
A steam reformer filled with a catalyst, a Ni catalyst and the like is used. The fuel gas containing hydrogen as a main component discharged from the steam reformer 4 is sent to the carbon monoxide converter 5 in the same manner as in the related art, so that the carbon monoxide content is reduced and the hydrogen content is increased. Next, the fuel gas discharged from the carbon monoxide converter 5 is sent to the fuel electrode 7 of the fuel cell body 6 and undergoes an electrochemical reaction with oxygen in the air 9 flowing into the oxidant electrode 10 by the compressor 8. As a result, part of the fuel gas is consumed, electric energy is obtained, and water is by-produced.

The processing of the fuel gas discharged from the fuel electrode 7 (for example, the fuel gas is sent to the burner 11 and burned to be used as a heating source of the steam reformer 4), and the oxidizer electrode 10
The treatment of the exhaust gas discharged from the fuel cell, the cooling of the fuel cell body 6, the cooling water circuit, and the like are the same as in the conventional apparatus.

The present invention is not limited to the above-described embodiment, but can be implemented in various modifications without departing from the scope of the invention, and various conventionally known mechanisms can be added. For example, a mechanism for controlling the fuel gas supplied to the fuel electrode 7 and the air 9 supplied to the oxidant electrode 10 according to the load, or adjusting the differential pressure by detecting the differential pressure between the fuel electrode 7 and the oxidant electrode 10 A plurality of fuel cell bodies 6 may be connected in parallel or in series. Further, a fuel recirculation fan is provided between the fuel gas supply line and the fuel gas discharge line of the fuel electrode 7 to return a part of the discharged fuel gas to the fuel electrode 7,
A mechanism may be provided in which an air recirculation fan is provided between the air supply line and the air discharge line to return a part of the discharged air to the oxidant electrode 10. By providing these recirculation mechanisms, it is possible to reuse the reactive gas after the electrode reaction and adjust the hydrogen concentration of the exhaust fuel gas and the oxygen concentration of the exhaust air to adjust the load fluctuation of the fuel cell. it can. Note that an inverter may be provided between the battery and the load according to the load form of the electric load 19.

Hereinafter, the present invention will be described in more detail with reference to Test Examples and Comparative Examples, but the present invention is not limited to these Test Examples.

Test Example 1 A test was performed using the fuel cell power generation system shown in FIG. In addition, as a steam reformer, a Ru catalyst (Ru2
%, Carrying Al ₂ O ₃ ) (a catalyst layer length of about 1 m) filled with 5 l (bulk density of about 0.8 kg / l). Also,
As a desulfurization device, an aqueous solution of sodium carbonate is added as an alkaline substance to a mixed aqueous solution containing copper nitrate and zinc nitrate, and the resulting precipitate is washed and collected by filtration, and then is 1/8 inch in height × 1/8 inch in diameter. Approximately 300 tablets
C., and then the fired body [copper: zinc = about 1: 1 (atomic ratio)] was heated at a temperature of about 2% using nitrogen gas containing 2% by volume of hydrogen.
A desulfurization apparatus (desulfurized layer length: about 50 cm) filled with 20 l of a copper-zinc desulfurizing agent obtained by reduction treatment at 00 ° C was used.

As a raw fuel, a city gas 13A comprising the components shown in Table 1 below was preheated to 200 ° C. by a preheater, and then introduced into the desulfurizer at a rate of 10 m ³ / h for desulfurization. After the desulfurized gas is mixed with steam, it is introduced into a steam reformer, where S / C (moles of steam per mole of carbon in the raw fuel hydrocarbon) = 3.3, reaction temperature 450 ° C. (inlet) At 665 ° C. (outlet) and at a reaction pressure of 0.2 kg / cm ² · G. The steam-reformed fuel gas was led to the fuel electrode of the fuel cell main body through the carbon monoxide converter, and reacted with oxygen in the air introduced into the oxidant electrode to extract electric energy.

[0026]

Table 1 Methane 86.9% by volume Ethane 8.1% by volume Propane 3.7% by volume Butane 1.3% by volume Odorant dimethyl sulfide 3mg-S / Nm ² t-butyl mercaptan 2mg-S / Nm ²

In the above test, the sulfur content in the gas at the outlet of the desulfurizer was measured with time, and it was found that the sulfur content was 0.1 vol.ppb or less even after 2000 hours. The steam reforming catalyst did not show any deterioration in catalytic activity even after the lapse of 2000 hours, maintained the same activity as immediately after the start of the reaction, showed no carbon deposition, and operated the fuel cell normally. .

COMPARATIVE EXAMPLE 1 In the fuel cell power generation system shown in FIG. 2, a system using a desulfurizer filled with 5 liters of a Ni-Mo based hydrodesulfurization catalyst and 10 liters of zinc oxide as desulfurizing agents was produced, and a test example was performed. The fuel cell was operated as in 1. However,
The desulfurization temperature was 380 ° C., and the amount of recycled reformed gas supplied to the desulfurizer (that is, the fuel gas recycled from the carbon monoxide converter) was 2% by volume based on the raw fuel.

As a result, the sulfur content of the gas at the outlet of the desulfurization unit immediately after the start of the reaction was 0.2 ppm, and remained almost unchanged after that. As a result, the electric output of the fuel cell began to decrease, and eventually the device had to be stopped. At this time, carbon was deposited on the reforming catalyst and almost completely deteriorated.

Test Example 2 The fuel cell power generation system used in Test Example 1 was the same as Test Example 1 except that a heater and a cooler were temporarily installed before the desulfurization device so that the raw fuel could be heated or cooled. The fuel cell power generation system was operated in the same manner using the apparatus described above.
However, during this period, the temperature at the inlet of the desulfurization unit was set to 15 every 8 hours.
Over 20 minutes to about 20 ° C.
The operation of returning to 00 ° C. was performed. This simulates the conditions of the desulfurization device that the fuel cell power generation system receives when it is started up and stopped.

As a result, as in Test Example 1, a total of 2000
After the operation for a long time, the sulfur content in the gas at the outlet of the desulfurizer was 0.1 vol.ppb or less, no deterioration of the catalyst and no carbon deposition were observed, and the fuel cell operated normally.

Comparative Example 2 A fuel cell was operated in the same operation pattern as in Test Example 2, using the same apparatus as in Comparative Example 1. However, the width of the desulfurizer inlet temperature was set to 20 ° C to 380 ° C (normal use).

As a result, the sulfur content in the gas at the outlet of the desulfurizer was 0.2 ppm at the ordinary temperature, but reached 3 ppm when the temperature was lowered. Further, 200 hours after the start of the operation, the slip of the raw hydrocarbon increased at the outlet of the reformer, the electric output of the fuel cell began to decrease, and the device had to be stopped soon. At this time, carbon was deposited on the reforming catalyst and almost completely deteriorated.

Test Example 3 In Test Example 1, an aqueous sodium carbonate solution was added as an alkaline substance to a mixed aqueous solution in which copper nitrate, zinc nitrate and aluminum nitrate were dissolved as a copper-zinc desulfurizing agent to be charged into a desulfurization apparatus, and the resulting precipitate was formed. After washing and filtration, the mixture is tablet-molded into a size of 1/8 inch high x 1/8 inch diameter, fired at about 400 ° C, and then fired (copper oxide 45%).
Test Example 1 using a copper-zinc-aluminum desulfurizing agent obtained by reducing at a temperature of about 200 ° C. with nitrogen gas containing 2% by volume of hydrogen using a nitrogen gas containing 2% by volume of hydrogen. The same test was performed.

As a result, as in Test Example 1, it was found that the sulfur content in the gas at the outlet of the desulfurization device could be desulfurized to 0.1 vol.ppb or less, and the deterioration of the steam reforming catalyst and carbon deposition could be suppressed. And the fuel cell worked normally.

[0036]

According to the fuel cell power generation system of the present invention, the following effects can be obtained. (1) Desulfurization equipment with excellent desulfurization performance is used. The raw fuel is highly desulfurized and subjected to the steam reforming reaction. Therefore, deterioration of the steam reforming catalyst or carbon deposition is prevented, and the fuel cell is stable for a long time. In addition, the cost of the steam reforming catalyst can be reduced, and the size of the apparatus can be reduced.

(2) Since the high activity of the steam reforming catalyst can be maintained for a long time by preventing carbon deposition, high SV operation is possible, and the size of the apparatus and the cost of the catalyst can be reduced.
Further, low S / C operation becomes possible, which can contribute to improvement of thermal efficiency, power generation efficiency, and the like.

(3) Since desulfurization in a low temperature range is possible and there is no need to desulfurize at a high temperature unlike conventional hydrodesulfurization,
No special heating device is required, and it is possible to quickly respond to load fluctuations of the fuel cell.

(4) When conventional hydrodesulfurization is used in the desulfurization step, a hydrogen recycling line is required from a steam reformer or the like, but the system of the present invention does not require a hydrogen recycling line. The system has been simplified,
The size of the device can be reduced.

[Brief description of the drawings]

FIG. 1 is a system diagram showing an outline of an embodiment of a fuel cell power generation system of the present invention.

FIG. 2 is a system diagram showing an outline of a conventional fuel cell power generation system.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Raw fuel 2a ... Copper-zinc system desulfurizer 2b ... Hydrodesulfurizer 3 ... Mixer 4 ... Steam reformer 5 ... Carbon monoxide converter 6 ... Fuel cell body 7 ... Fuel electrode 8 ... Compressor 9 ... Air DESCRIPTION OF SYMBOLS 10 ... Oxidizer electrode 11 ... Burner 12 ... Heat exchanger 13 ... Condenser 14 ... Water supply line 15 ... Water supply pump 16 ... Cooling water pump 17 ... Heat exchanger 18 ... Steam separator 19 ... Electric load

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Susumu Takami 4-1-2, Hirano-cho, Chuo-ku, Osaka-shi, Osaka Inside Osaka Gas Co., Ltd. (72) Inventor Masamichi Ipponmatsu 4-chome, Hirano-cho, Chuo-ku, Osaka, Osaka No. 1-2 in Osaka Gas Co., Ltd.

Claims (5)

[Claims] 1. A fuel cell power generation system having at least a desulfurizer for desulfurizing a raw fuel and a steam reformer for reforming the desulfurized raw fuel into a fuel gas containing hydrogen as a main component, wherein the desulfurizer has a copper-zinc system. A fuel cell power generation system comprising a desulfurization device filled with a desulfurization agent. 2. The fuel cell power generation system according to claim 1, wherein the sulfur content of the raw fuel is reduced to 1 vol.ppb or less by the desulfurization device. 3. The fuel cell power generation system according to claim 2, wherein the sulfur content of the raw fuel is desulfurized to 0.1 vol.ppb or less by the desulfurization device. 4. A copper oxide prepared by a coprecipitation method using a copper compound and a zinc compound as a copper-zinc desulfurizing agent in a desulfurization apparatus.
A desulfurizing agent obtained by hydrogen-reducing a zinc oxide mixture, or a desulfurizing agent obtained by hydrogen-reducing a copper oxide-zinc oxide-aluminum oxide mixture prepared by a coprecipitation method using a copper compound, a zinc compound and an aluminum compound The fuel cell power generation system according to any one of claims 1 to 3, wherein 5. The raw fuel is a gaseous fuel.
The fuel cell power generation system according to any one of the above.