JP2019166487A - Desulfurizer for fuel gas, fuel gas desulfurization system and fuel gas desulfurization method - Google Patents

Abstract

To provide a desulfurizer for a fuel gas where plurality kinds of sulfur compounds contained in the fuel gas can be efficiently adsorbed and removed, the used amount of silver-carried zeolite can be reduced in comparison with a conventional desulfurizer using silver-carried zeolite and the downsizing of the desulfurizer can be realized.SOLUTION: A desulfurizer for a fuel gas includes: a first desulfurization part provided with a first desulfurization agent; a second desulfurization part disposed in a downstream in the gas flow direction of the first desulfurization part and provided with a second desulfurization agent; and a third desulfurization part disposed in a downstream in the gas flow direction of the second desulfurization part and provided with a third desulfurization agent. The first desulfurization agent and the third desulfurization agent contain activated carbon and a metal attached to the activated carbon. The metal contained in the first desulfurization agent contains copper. The metal contained in the third desulfurization agent contains at least one kind selected from the group consisting of nickel, tungsten and molybdenum. The second desulfurization agent contains silver-carried zeolite.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a fuel gas desulfurizer, a fuel gas desulfurization system, and a fuel gas desulfurization method.

  Fuel gas, such as city gas, liquefied petroleum (LP) gas, and natural gas, includes lower hydrocarbon gases such as methane, ethane, propane, and butane, so it can only be used as industrial fuel and household fuel. It is also used as a raw material for producing hydrogen.

In the steam reforming method, which is one of the industrial production methods of hydrogen, reforming of the lower hydrocarbon gas as described above by reforming with the addition of steam in the presence of a catalyst. Generate gas. However, when the catalyst used in the steam reforming method is poisoned by a sulfur compound, the catalytic function is lowered.
For example, in the case of a fuel cell system, not only the catalyst of the reformer but also the electrode catalyst in the power generation cell is affected by the poisoning by the sulfur compound. It is desirable to be removed. Generally, in a fuel cell system, sulfur compounds contained in fuel gas are removed using a desulfurizer.

  Known desulfurization methods include a room temperature adsorption desulfurization method and a hydrodesulfurization method. The room temperature adsorptive desulfurization method is a desulfurization method in which a gas is circulated in a vessel filled with a desulfurizing agent at room temperature, and a sulfur compound contained in the gas is physically or chemically adsorbed on the surface of the desulfurizing agent. It is often used because of its simple operation compared with hydrodesulfurization.

As a desulfurization technique of the room temperature adsorption desulfurization system, many techniques using a metal-supported zeolite as a desulfurization agent have been reported.
For example, as a desulfurization agent that simultaneously adsorbs and removes sulfides and mercaptans in fuel gas such as city gas, LP gas, and natural gas, an adsorbent for removing sulfur compounds formed by supporting silver by ion exchange on Y-type zeolite ( A so-called silver-supported zeolite has been reported (for example, see Patent Document 1).
In addition, a desulfurization method having a multi-stage configuration in which a part of a sulfur compound to be adsorbed and removed is removed with silver-supported zeolite and then the remaining sulfur compound is removed with another adsorbent (for example, metal oxide) has been reported. (For example, see Patent Documents 2 and 3).

Japanese Patent No. 4026700 Japanese Patent No. 4749589 Japanese Patent Laying-Open No. 2015-135789

By the way, various kinds of sulfur compounds are contained in the fuel gas. For example, in fuel gas, as an odorant added for the purpose of detecting leakage, methyl mercaptan (MM), ethyl mercaptan (EM), tert-butyl mercaptan (TBM: tertiary-butyl) mercaptan), sulfides such as dimethyl sulfide (DMS), diethyl sulfide (DES), dimethyl disulfide (DMDS), and thiophenes such as tetrahydrothiophene (THT). Contains sulfur compounds.
Commonly added odorants are TBM, DMS, and THT. For example, in city gas, both TBM and DMS are often used. The concentration of these odorants contained in the fuel gas is about several ppm.
City gas contains sulfur compounds other than odorants such as those derived from raw materials such as hydrogen sulfide (H ₂ S) and carbonyl sulfide (COS), and those mixed while flowing through the conduit. There is also.

When the sulfur compounds to be adsorbed are diverse such as mercaptans, sulfides, thiophenes, etc., if all of these sulfur compounds are adsorbed and removed only by the silver-supported zeolite described in Patent Document 1, silver support A large amount of zeolite is required. Since the silver-supported zeolite is expensive, the desulfurization cost increases as the amount used increases.
On the other hand, in the multi-stage desulfurization system described in Patent Documents 2 and 3, a single-stage structure using only the silver-supported zeolite described in Patent Document 1 is obtained by combining the silver-supported zeolite with another adsorbent. The amount of silver-supported zeolite can be reduced as compared with the desulfurization method. However, when a plurality of sulfur compounds are contained in the fuel gas, the amount of silver-supported zeolite cannot be reduced so much.

  Considering that the spread of household fuel cell systems has become realistic in recent years, as a desulfurizer for fuel gas, it adsorbs multiple types of sulfur compounds contained in fuel gas at a lower cost. It can be said that it must be removable and can be reduced in size.

  The present invention has been made in view of the circumstances as described above, and is capable of efficiently adsorbing and removing a plurality of types of sulfur compounds contained in a fuel gas, and using a conventional silver-supported zeolite. The amount of silver-supported zeolite can be reduced as compared with a reactor, and a desulfurizer for fuel gas that can reduce the size of the desulfurizer, a fuel gas desulfurization system including the same, and a fuel gas using the same An object is to provide a desulfurization method.

Specific means for solving the above problems include the following embodiments.
<1> A first desulfurization section provided with a first desulfurization agent, a second desulfurization section provided downstream of the first desulfurization section in the gas flow direction, and provided with a second desulfurization agent, and the second A third desulfurization section that is disposed downstream of the desulfurization section in the gas flow direction and includes a third desulfurization agent. The first desulfurization agent and the third desulfurization agent are attached to the activated carbon and the activated carbon. The metal included in the first desulfurizing agent includes copper, and the metal included in the third desulfurizing agent is selected from the group consisting of nickel, tungsten, and molybdenum. A fuel gas desulfurizer comprising at least one kind, wherein the second desulfurizing agent includes a zeolite on which silver is supported.
<2> The metal contained in the first desulfurizing agent and the third desulfurizing agent each independently includes at least one selected from the group consisting of copper and nickel, tungsten, and molybdenum. 1> The fuel gas desulfurizer according to 1>.
<3> The first desulfurizing agent and the third desulfurizing agent include copper and nickel as the metal, and the ratio of the addition amount of the nickel to the addition amount of the copper is independently based on mass. The desulfurizer for fuel gas according to <2>, which is in the range of 0.20 to 2.70.
<4> The first desulfurizing agent and the third desulfurizing agent include copper and tungsten as the metal, and the ratio of the addition amount of the tungsten to the addition amount of the copper is independently based on mass. The desulfurizer for fuel gas according to <2>, which is in the range of 0.10 to 0.60.
<5> The first desulfurizing agent and the third desulfurizing agent include copper and molybdenum as the metal, and the ratio of the addition amount of the molybdenum to the addition amount of the copper is independently based on mass. The desulfurizer for fuel gas according to <2>, which is in the range of 0.15 to 2.00.
<6> A first desulfurization section provided with a first desulfurization agent, a second desulfurization section provided downstream of the first desulfurization section in the gas flow direction, and provided with a second desulfurization agent, and the second A third desulfurization section that is disposed downstream of the desulfurization section in the gas flow direction and includes a third desulfurization agent, wherein the first desulfurization agent includes activated carbon and a metal attached to the activated carbon. The metal includes copper, the second desulfurizing agent includes zeolite on which silver is supported, and the third desulfurizing agent has higher carbonyl sulfide adsorptivity than the zeolite on which silver is supported. Desulfurizer for fuel gas.
<7> The fuel gas desulfurizer according to <6>, wherein the metal includes copper and at least one selected from the group consisting of nickel, tungsten, and molybdenum.

<8> A fuel gas desulfurization system comprising: the fuel gas desulfurizer according to any one of <1> to <7>, and a fuel gas supply source that supplies the fuel gas to the fuel gas desulfurizer.
<9> The fuel gas desulfurization system according to <8>, wherein the fuel gas is city gas, liquefied petroleum gas, natural gas, digestion gas, or exhaust gas.
<10> A fuel cell that generates power using the fuel gas desulfurized in the fuel gas desulfurizer, and a hydrogen production that produces hydrogen using the fuel gas desulfurized in the fuel gas desulfurizer The fuel gas desulfurization system according to <8> or <9>, further comprising at least one of apparatuses.

  <11> A fuel gas desulfurization method in which fuel gas is supplied to the fuel gas desulfurizer according to any one of <1> to <7> to perform desulfurization.

  According to the present invention, it is possible to efficiently adsorb and remove a plurality of types of sulfur compounds contained in fuel gas, and the amount of silver-supported zeolite used compared to a conventional desulfurizer using silver-supported zeolite. It is possible to provide a fuel gas desulfurizer capable of reducing the size of the desulfurizer, a fuel gas desulfurization system including the same, and a fuel gas desulfurization method using the same.

It is a schematic block diagram which shows the desulfurizer for fuel gas of one Embodiment. It is a schematic structure figure showing a fuel gas desulfurization system of one embodiment. It is the schematic of the desulfurizer used for the evaluation test of Example 1 and Comparative Examples 1 and 2. It is a graph which shows the desulfurization agent required amount when the desulfurizer for fuel gas of Example 1 and Comparative Examples 1 and 2 is used.

  Hereinafter, specific embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments, and may be implemented with appropriate modifications within the scope of the object of the present invention. can do.

In the present disclosure, a numerical range indicated using “to” means a range including the numerical values described before and after “to” as the minimum value and the maximum value, respectively.
In the numerical ranges described stepwise in the present disclosure, the upper limit value or the lower limit value described in one numerical range may be replaced with the upper limit value or the lower limit value of another numerical description. . Further, in the numerical ranges described in the present disclosure, the upper limit value or the lower limit value of the numerical range may be replaced with the values shown in the examples.
In the present disclosure, the amount of each component in the desulfurizing agent is the total amount of the plurality of substances present in the desulfurizing agent unless there is a specific indication when there are a plurality of substances corresponding to each component in the desulfurizing agent. means.

«Desulfurizer for fuel gas according to one embodiment»
[Desulfurizer for fuel gas]
A fuel gas desulfurizer according to an embodiment of the present invention includes a first desulfurization unit including a first desulfurization agent, and a second desulfurization agent that is disposed downstream of the first desulfurization unit in the gas flow direction. A second desulfurization section; and a third desulfurization section that is disposed downstream of the second desulfurization section in the gas flow direction and includes a third desulfurization agent. The first desulfurization agent and the third desulfurization agent The desulfurizing agent includes activated carbon and a metal adhering to the activated carbon, the metal included in the first desulfurizing agent includes copper, and the metal included in the third desulfurizing agent is nickel. And at least one selected from the group consisting of tungsten and molybdenum, and the second desulfurizing agent includes zeolite on which silver is supported (silver-supported zeolite).
According to the desulfurizer for fuel gas of one embodiment, a plurality of types of sulfur compounds contained in the fuel gas can be efficiently adsorbed and removed, and compared with a desulfurizer using a conventional silver-supported zeolite. In addition, the amount of silver-supported zeolite can be reduced, and the desulfurizer can be downsized.
The present inventors presume the reason why the fuel gas desulfurizer of one embodiment can achieve such an effect as follows.

  The fuel gas desulfurizer according to one embodiment includes a first desulfurization unit including a first desulfurization agent, a second desulfurization unit including a second desulfurization agent, and a third gas flow downstream in the gas flow direction. And a third desulfurization part including the desulfurization agent in this order. Therefore, the fuel gas containing the sulfur compound supplied to the fuel gas desulfurizer flows in the order of the first desulfurization section, the second desulfurization section, and the third desulfurization section.

  The first desulfurizing agent is a desulfurizing agent in which copper is impregnated with activated carbon, is excellent in desulfurizing performance, and can efficiently adsorb and remove a plurality of types of sulfur compounds contained in fuel gas. For example, the first desulfurizing agent is particularly excellent in the adsorptivity of mercaptans (eg, TBM), which are main sulfur compounds contained in city gas, liquefied petroleum (LP) gas, and the like.

  Next, the second desulfurizing agent is a desulfurizing agent containing silver-supported zeolite, and has an excellent ability to adsorb sulfur compounds. For example, sulfides (sulfide compounds which are sulfur compounds contained in city gas, liquefied petroleum (LP) gas, etc.) For example, it is particularly excellent in the adsorption ability of DMDS).

  By the way, various kinds of sulfur compounds are contained in the fuel gas, and it is difficult to adsorb and remove these simultaneously. Silver-supported zeolite is excellent in the ability to adsorb sulfur compounds such as sulfides (for example, DMDS). However, in order to adsorb all of a plurality of types of sulfur compounds, it is necessary to increase the amount used. However, since the silver-supported zeolite is expensive, it is preferable to reduce the amount used as much as possible.

  The fuel gas desulfurizer according to an embodiment includes a third desulfurization unit including a third desulfurization agent downstream of the second desulfurization unit in the gas flow direction. The third desulfurizing agent is a desulfurizing agent in which a specific metal (that is, at least one selected from the group consisting of nickel, tungsten, and molybdenum) is attached to activated carbon, and is excellent in desulfurization performance and in the fuel gas. A plurality of kinds of contained sulfur compounds can be efficiently adsorbed and removed. For example, the third desulfurizing agent tends to be excellent in adsorption capacity such as COS. Therefore, in the fuel gas desulfurizer according to one embodiment, the sulfur compound that has not been adsorbed by the second desulfurization unit including the second desulfurization agent can be adsorbed by the third desulfurization unit including the third desulfurization agent. It has become a structure. Therefore, it is possible to adsorb sulfur compounds in the third desulfurization part while reducing the amount of silver-supported zeolite used in the second desulfurization part.

  That is, the fuel gas desulfurizer of one embodiment selects, as a desulfurization agent, activated carbon impregnated with copper, activated carbon impregnated with a specific metal, and silver-supported zeolite, and the fuel gas, This is a desulfurization type desulfurization system having a multi-stage configuration in which after passing through activated carbon impregnated with copper, the zeolite carrying silver is circulated, and then the activated carbon is impregnated with a specific metal. With this configuration, it is possible to efficiently adsorb and remove a plurality of types of sulfur compounds contained in the fuel gas while reducing the amount of silver-supported zeolite. In addition, the combination of activated carbon impregnated with copper and activated carbon impregnated with a specific metal is excellent in sulfur compound adsorption performance, so a plurality of types of sulfur compounds contained in fuel gas in a relatively small amount Can be adsorbed and removed. Therefore, in the fuel gas desulfurizer of one embodiment, the amount of the entire desulfurizing agent used can be reduced. As a result, downsizing of the desulfurizer can be realized.

Normally, when LP gas is used as fuel gas, LP gas contains more sulfur compounds than city gas, and contains more hydrocarbon components that inhibit desulfurization, so a larger amount of desulfurization agent must be installed. In addition, a large amount of silver-supported zeolite is required. In particular, silver-supported zeolite has a large reduction in COS adsorption capacity in LP gas compared to COS adsorption capacity in city gas, so a large amount of silver-supported zeolite is required when LP gas is desulfurized. There is a problem of becoming.
On the other hand, in the fuel gas desulfurizer of one embodiment, sulfur compounds that have not been adsorbed by the second desulfurization unit that includes the second desulfurization agent can be adsorbed by the third desulfurization unit that includes the third desulfurization agent. Therefore, even when LP gas is used as the fuel gas, the sulfur compound can be efficiently removed while greatly reducing the amount of silver-carrying zeolite used.

  The first desulfurizing agent and the third desulfurizing agent are preferably desulfurizing agents obtained by adding activated carbon and at least one selected from the group consisting of nickel, tungsten, and molybdenum to activated carbon. As a result, the first desulfurizing agent and the third desulfurizing agent can more efficiently adsorb and remove a plurality of types of sulfur compounds contained in the fuel gas, and also tend to be excellent in adsorption capacity such as COS. .

  By the way, thiophenes may be contained in the fuel gas as a sulfur compound. Thiophenes may be oxidized on the desulfurizing agent and become thiophenes that are difficult to remove by adsorption. When the first desulfurizing agent is a desulfurizing agent in which copper and a specific metal (that is, at least one selected from the group consisting of nickel, tungsten, and molybdenum) are attached to activated carbon, in the fuel gas Even when a sulfur compound capable of producing thiophene is contained in thiophene, it is difficult to produce thiophene.

For example, when the first desulfurization agent is a desulfurization agent in which copper and nickel are impregnated into activated carbon, sulfur that can generate thiophene in the fuel gas as a result of suppressing the oxidizing power of copper by nickel. Even when a compound is contained, the production of thiophene is considered to be suppressed.
In the first desulfurization agent, it is considered that most of the metal is attached to the activated carbon as a compound containing a metal element (oxide, inorganic acid salt, organic acid salt, etc., particularly oxide). When the first desulfurizing agent is a desulfurizing agent in which activated carbon is combined with a combination of copper and tungsten or a combination of copper and molybdenum, the oxide of tungsten and the oxide of molybdenum have many oxygen vacancies. Therefore, it is considered that the generation of thiophene is suppressed by adsorbing sulfur of a sulfur compound capable of generating thiophene in the deficient portion.

  Examples of thiophenes that can generate thiophene by a reaction such as oxidation include thiophenes such as tetrahydrothiophene (THT), 2-methylthiophene, benzothiophene, dibenzothiophene, 4-methyldibenzothiophene, and 4,6-dimethyldibenzothiophene. Kind.

  Hereinafter, the desulfurizer for fuel gas of one Embodiment is demonstrated in detail.

First, a fuel gas desulfurizer according to an embodiment will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram illustrating a fuel gas desulfurizer according to an embodiment.
A fuel gas desulfurizer 1 according to an embodiment includes a first desulfurization section 10 including a first desulfurization agent, and a first desulfurization section 10 disposed downstream of the first desulfurization section 10 in the gas flow direction, and includes a second desulfurization agent. 2 desulfurization part 20 and the 3rd desulfurization part 30 provided in the gas distribution direction downstream of the 2nd desulfurization part 20, and provided with the 3rd desulfurization agent.

The first desulfurization agent (not shown) included in the first desulfurization unit 10 includes activated carbon and a metal attached to the activated carbon. The metal includes copper, and the third desulfurizing agent 30 is included. The third desulfurizing agent (not shown) included in the above includes activated carbon and a metal attached to the activated carbon, and the metal includes at least one selected from the group consisting of nickel, tungsten, and molybdenum. Including.
The first desulfurizing agent and the third desulfurizing agent include activated carbon and a metal attached to the activated carbon, and the metal is at least selected from the group consisting of copper, nickel, tungsten, and molybdenum. 1 type may be included. At this time, the metals contained in the first desulfurizing agent and the third desulfurizing agent may be the same or different.

The second desulfurization agent (not shown) included in the second desulfurization unit 20 includes zeolite (silver-supported zeolite) on which silver is supported.
In the fuel gas desulfurizer 1 of one embodiment, the fuel gas containing a sulfur compound flows in the direction of the arrow shown in FIG. That is, after the fuel gas containing the sulfur compound supplied to the fuel gas desulfurizer 1 circulates through the first desulfurization unit 10 including the first desulfurization agent, the second desulfurization unit including the second desulfurization agent 20, and then through a third desulfurization section 30 having a third desulfurizing agent, a plurality of types of sulfur compounds contained in the fuel gas are converted into a first desulfurizing agent and a second desulfurizing agent. And adsorbed on the third desulfurizing agent and removed.

  The fuel gas containing the sulfur compound supplied to the fuel gas desulfurizer 1 first circulates through the first desulfurization section 10 including the first desulfurization agent. Since the first desulfurizing agent can efficiently adsorb plural kinds of sulfur compounds contained in the fuel gas, it exhibits an excellent adsorbing ability with a relatively small amount of use. After most of the sulfur compounds in the fuel gas flowing through the first desulfurizing section 10 including the first desulfurizing agent are removed by the first desulfurizing agent, the fuel gas includes the second desulfurizing agent. It distribute | circulates the 2nd desulfurization part 20, and distribute | circulates the 3rd desulfurization part 30 provided with a 3rd desulfurization agent next. Of the sulfur compounds that have not been removed by the first desulfurizing agent in the third desulfurizing agent, sulfur compounds that cannot be adsorbed by the second desulfurizing agent can be removed, so the second desulfurizing agent is often used. There is no need. As a result, it is possible to efficiently adsorb and remove multiple sulfur compounds contained in fuel gas while reducing the amount of silver-supported zeolite used compared to conventional desulfurizers using silver-supported zeolite. Therefore, it is possible to reduce the size of the desulfurizer.

[First desulfurization section]
The first desulfurization unit includes a first desulfurization agent.
In the first desulfurization section, most of the plurality of types of sulfur compounds contained in the fuel gas are removed by the first desulfurization agent.

<First desulfurizing agent>
The first desulfurizing agent includes activated carbon and a metal attached to the activated carbon, and the metal includes copper. The metal preferably includes a combination of copper and at least one selected from the group consisting of nickel, tungsten, and molybdenum.
Since the first desulfurizing agent has the above-described configuration, it is possible to efficiently adsorb and remove a plurality of types of sulfur compounds contained in the fuel gas.

(Activated carbon)
The first desulfurizing agent includes at least one activated carbon.
As the activated carbon, any activated carbon that is usually used in the technical field can be used without particular limitation.

Examples of the activated carbon raw material include coconut shell, coal (anthracite, bituminous coal, etc.), wood flour, peat charcoal, bamboo charcoal and the like.
Among these, as a raw material for activated carbon, coconut shell is preferable from the viewpoint of a small average pore diameter and a small impurity content.

The activated carbon is preferably activated carbon treated with an inorganic acid. When the activated carbon is treated with an inorganic acid, impurities are removed, the specific surface area is improved, and the surface of the activated carbon is hydrophilized, so that the dispersibility of the attached metal can be further improved.
Examples of inorganic acids for treating activated carbon include hydrochloric acid, nitric acid, sulfuric acid and the like.

The shape of the activated carbon is not particularly limited, and examples thereof include granular, columnar (for example, columnar), fibrous, honeycomb, and crushed.
Among these, as the shape of the activated carbon, for example, from the viewpoint of cost, at least one shape selected from the group consisting of granular, columnar, and crushed is preferable, and the density is high and fine powder is used. From the viewpoint of not including it, at least one shape selected from a granular shape and a columnar shape is more preferable.

When the shape of the activated carbon is granular, the average particle diameter of the activated carbon is, for example, from the viewpoint of preventing gas drift and the mesh interval of the desulfurization agent outflow prevention filter when the gas flow rate is 10 L (liter) / min or less. 0.5 mm or more and 5.0 mm or less is preferable, and 1.0 mm or more and 3.0 mm or less is more preferable.
In the present disclosure, the “average particle diameter” refers to a volume average particle diameter (Mv), which is a value measured using a laser diffraction / scattering particle size distribution measuring apparatus.

For example, the specific surface area of the activated carbon is preferably 600 m ² / g or more, more preferably 1300 m ² / g or more, from the viewpoint of improving the dispersity of the impregnated metal.
In the present disclosure, the “specific surface area” is a value measured by the BET method.

The average pore diameter of the activated carbon is preferably 0.9 nm or more and 2.0 nm or less, and preferably 0.9 nm or more and 1.5 nm or less, for example, from the viewpoint that the pore diameter matches the molecular diameter of the sulfur compound. More preferred.
In the present disclosure, the “average pore diameter” is a value measured by a nitrogen gas adsorption method.

(metal)
The first desulfurizing agent includes a metal adhering to the above-described activated carbon, and the metal includes copper (Cu), preferably from copper, nickel (Ni), tungsten (W), and molybdenum (Mo). A combination of at least one selected from the group consisting of:
Most of the above metals attached to activated carbon are considered to be contained as compounds containing metal elements (oxides, inorganic acid salts, organic acid salts, etc.), but they may be contained as simple metals. .

When the metal includes a combination of copper and at least one selected from the group consisting of nickel, tungsten, and molybdenum, the metal combined with copper may be a single metal or a combination of two or more metals. There may be. The metal may be a combination of copper and nickel, a combination of copper and tungsten, or a combination of copper and molybdenum.
The metal may be a combination of copper, nickel and tungsten, may be a combination of copper, nickel and molybdenum, may be a combination of copper, tungsten and molybdenum, A combination of nickel, tungsten and molybdenum may be used.

The amount of copper added is preferably, for example, 1.0% by mass or more and 20.0% by mass or less, and 2.0% by mass or more and 15.0% by mass or less with respect to the total mass of the first desulfurizing agent. More preferably, it is 2.0 mass% or more and 8.0 mass% or less.
When the metal combined with copper is nickel, the amount of nickel attached is preferably 1.0% by mass or more and 20.0% by mass or less with respect to the total mass of the first desulfurizing agent, for example. It is more preferably 0% by mass or more and 15.0% by mass or less, and further preferably 2.0% by mass or more and 8.0% by mass or less.
When the metal combined with copper is tungsten, the amount of tungsten attached is preferably 1.0% by mass or more and 20.0% by mass or less with respect to the total mass of the first desulfurizing agent, for example. It is more preferably 0% by mass or more and 15.0% by mass or less, and further preferably 2.0% by mass or more and 8.0% by mass or less.
When the metal combined with copper is molybdenum, the amount of molybdenum attached is preferably 1.0% by mass or more and 20.0% by mass or less with respect to the total mass of the first desulfurizing agent, for example. It is more preferably 0% by mass or more and 15.0% by mass or less, and further preferably 2.0% by mass or more and 8.0% by mass or less.

When the metal combined with copper is nickel, the ratio of the amount of nickel to the amount of copper deposited (the amount of nickel deposited / the amount of copper deposited) is in the range of 0.20 to 2.70 on a mass basis. Is more preferable, is in the range of 0.20 to 2.50, more preferably is in the range of 0.30 to 2.00, and is particularly preferably in the range of 0.30 to 1.00. .
When the ratio of the amount of nickel added to the amount of copper added is within the above range, the sulfur compound contained in the fuel gas can be adsorbed and removed more efficiently, and thiophene can be generated in the fuel gas. When a sulfur compound is included, the production of thiophene can be further suppressed.

When the metal combined with copper is tungsten, the ratio of the amount of tungsten added to the amount of copper attached (the amount of tungsten attached / the amount of copper attached) is in the range of 0.10 to 0.60 on a mass basis. Is preferable, and the range of 0.15 to 0.60 is more preferable.
When the ratio of the amount of tungsten added to the amount of copper added is within the above range, sulfur compounds contained in the fuel gas can be adsorbed and removed more efficiently, and thiophene can be generated in the fuel gas. When a sulfur compound is included, the production of thiophene can be further suppressed.
From the standpoint of more efficiently adsorbing and removing sulfur compounds contained in the fuel gas, the ratio of the tungsten adhesion amount to the copper adhesion amount (tungsten adhesion amount / copper adhesion amount) is 0 on a mass basis. More preferably, it is in the range of 15 to 0.55.
Further, from the viewpoint of further suppressing the generation of thiophene, the ratio of the amount of tungsten attached to the amount of copper attached (the amount of tungsten attached / the amount of copper attached) is in the range of 0.25 to 0.60 on a mass basis. More preferably.

When the metal combined with copper is molybdenum, the ratio of molybdenum deposition amount to copper deposition amount (molybdenum deposition amount / copper deposition amount) is in the range of 0.15 to 2.00 on a mass basis. Is preferable, and the range of 0.15 to 1.80 is more preferable.
When the ratio of the molybdenum deposition amount to the copper deposition amount is within the above range, the sulfur compound contained in the fuel gas can be adsorbed and removed more efficiently, and thiophene can be generated in the fuel gas. When a sulfur compound is included, the production of thiophene can be further suppressed.
From the viewpoint of more efficiently absorbing and removing sulfur compounds contained in the fuel gas, the ratio of the molybdenum adhesion amount to the copper adhesion amount (molybdenum adhesion amount / copper adhesion amount) is 0 on a mass basis. More preferably, it is in the range of 15 to 1.60.
Further, from the viewpoint of further suppressing the generation of thiophene, the ratio of the molybdenum adhesion amount to the copper adhesion amount (molybdenum adhesion amount / copper adhesion amount) is in the range of 0.20 to 1.60 on a mass basis. It is more preferable that it is in the range of 0.30 to 1.60.

When the metal adhering to the activated carbon contains copper and nickel, the amount of copper adhering is preferably 20% by mass or more and 80% by mass or less with respect to the total mass of the metal adhering to the activated carbon, for example, 30 More preferably, they are 40 mass% or more and 80 mass% or less, More preferably, they are 40 mass% or more and 80 mass% or less, Especially preferably, they are 40 mass% or more and 65 mass% or less.
The amount of nickel added is preferably 20% by mass or more and 80% by mass or less, and more preferably 20% by mass or more and 70% by mass or less, with respect to the total mass of the metal added to the activated carbon. The content is more preferably 20% by mass or more and 60% by mass or less, and particularly preferably 35% by mass or more and 60% by mass or less.

When the metal adhering to the activated carbon contains copper and tungsten, the amount of copper adhering is preferably, for example, 50% by mass or more and 85% by mass or less with respect to the total mass of the metal adhering to the activated carbon. More preferably, it is at least 75% by mass.
Moreover, the amount of tungsten added is preferably 15% by mass or more and 50% by mass or less, and more preferably 25% by mass or more and 50% by mass or less, with respect to the total mass of the metal added to the activated carbon. preferable.

When the metal adhering to the activated carbon contains copper and molybdenum, the amount of copper adhering is preferably 30% by mass or more and 85% by mass or less with respect to the total mass of the metal adhering to the activated carbon, for example, 35 More preferably, it is at least 85% by mass.
Further, the amount of molybdenum added is preferably 15% by mass or more and 70% by mass or less, and more preferably 15% by mass or more and 65% by mass or less with respect to the total mass of the metal added to the activated carbon. preferable.

  In the present disclosure, the amount of metal attached to activated carbon (that is, the amount of attachment) is a value measured by ICP (Inductively Coupled Plasma) emission spectrometry. As the measuring device, for example, Optima 8000 (product name) manufactured by Perkin-Elmer can be suitably used. However, the measuring device is not limited to this.

(Other ingredients)
The first desulfurizing agent includes, as necessary, other components other than activated carbon, copper, and at least one selected from the group consisting of nickel, tungsten, and molybdenum as long as the effects of the present invention are not impaired. But you can.
The 1st desulfurization agent may contain metals other than copper, nickel, tungsten, and molybdenum as an unavoidable component in the range which does not impair the effect of this invention.

-Shape of first desulfurizing agent-
The shape of the first desulfurizing agent is not particularly limited and can be appropriately selected according to the purpose.
Examples of the shape of the first desulfurizing agent include granular shapes, columnar shapes (for example, columnar shapes), fibrous shapes, honeycomb shapes, and crushed shapes.
Among these, as the shape of the first desulfurizing agent, for example, from the viewpoint of cost, at least one shape selected from the group consisting of granular, columnar, and crushed is preferable, and the high density and From the viewpoint of not containing fine powder, at least one shape selected from granular and columnar is more preferable.

-Method for producing first desulfurizing agent-
The manufacturing method of a 1st desulfurizing agent is not restrict | limited in particular, A well-known method is employ | adopted as a method of attaching a metal to activated carbon, and a 1st desulfurizing agent can be manufactured.

An example of the manufacturing method of a 1st desulfurization agent is demonstrated. The first desulfurizing agent can be produced, for example, by the following method. However, the manufacturing method of a 1st desulfurization agent is not limited to this.
(1) A solution (impregnation solution) in which a metal compound containing a metal element to be attached to activated carbon is dissolved or dispersed in a solvent is prepared.
(2) The activated carbon is immersed in the impregnation solution.
(3) The activated carbon immersed in the impregnation solution is dried and the solvent is removed.
(4) The dried activated carbon is fired to form a metal oxide or the like on the activated carbon to obtain a metal-impregnated carbon (first desulfurizing agent).
The first desulfurizing agent can be produced by the above method.

Examples of the metal compound for preparing the impregnation solution include metal salts such as metal nitrate, metal acetate, metal sulfate, metal chloride, and metal phosphate.
Specifically, copper nitrate trihydrate, copper acetate monohydrate, nickel nitrate hexahydrate, nickel acetate tetrahydrate, 12-tungstophosphoric acid n hydrate, ammonium molybdate tetrahydrate Etc.

The solvent for preparing the impregnating solution is not particularly limited, and water, acidic aqueous solution (such as aqueous nitric acid solution), basic aqueous solution (such as aqueous ammonia solution), alcohol solvent (such as methanol, ethanol, n-propanol), ketone Examples include solvent based solvents (acetone, methyl ethyl ketone, etc.), ether solvents (diethyl ether, etc.), ester solvents (ethyl acetate, butyl acetate, etc.) and hydrocarbon solvents (toluene, etc.).
Among these, as a solvent for preparing the impregnation solution, water is preferable from the viewpoint that it does not remain after firing.
In the preparation of the impregnation solution, one type of solvent may be used alone, or two or more types may be mixed and used.

  The concentration of the metal compound in the impregnation solution is not particularly limited, and can be appropriately set according to, for example, the type of metal compound, the amount of metal attached to the activated carbon, the type of activated carbon, and the like.

The immersion temperature is not particularly limited, and can be in the range of 10 ° C to 80 ° C, for example.
The immersion time is not particularly limited, and can be in the range of, for example, 5 minutes to 2 hours.

The drying method is not particularly limited, and examples thereof include a method of drying by heating.
The heating temperature is not particularly limited and can be, for example, in the range of 50 ° C to 150 ° C.

The firing temperature is preferably in the range of 150 ° C. to 300 ° C., for example, from the viewpoint of promoting the decomposition of the metal compound and suppressing the ignition of the metal-impregnated coal.
The firing time is not particularly limited, and can be, for example, in the range of 1 hour to 24 hours.

[Second desulfurization section]
The second desulfurization section is arranged downstream of the first desulfurization section described above in the gas flow direction and includes a second desulfurization agent.
In the second desulfurization section, the sulfur compound that cannot be adsorbed by the first desulfurization agent and the sulfur compound (for example, thiophene) that can be generated in the first desulfurization agent are adsorbed to the second desulfurization agent and removed.
Since the kind and amount of the sulfur compound in the fuel gas flowing through the first desulfurization part are reduced by the first desulfurization agent, the second desulfurization agent does not require a large amount of use.

<Second desulfurizing agent>
The second desulfurization agent includes zeolite on which silver is supported (silver-supported zeolite).
When the second desulfurizing agent contains silver-supported zeolite, the sulfur compound that cannot be adsorbed by the first desulfurizing agent and the sulfur compound (for example, thiophene) that can be generated in the first desulfurizing agent can be adsorbed and removed. it can.

(Silver supported zeolite)
Silver zeolite is one in which silver (Ag) is supported on zeolite, and can efficiently adsorb and remove a plurality of types of sulfur compounds contained in the fuel gas regardless of the water concentration in the fuel gas.
The zeolite is not particularly limited, and examples thereof include X-type zeolite, Y-type zeolite, and β-type zeolite.
Among these, as the zeolite, for example, Y-type zeolite is preferable from the viewpoint of desulfurization performance, and β-type zeolite is particularly preferable when the water concentration is high.

The supported amount of silver is preferably 3% by mass or more based on the total mass of the zeolite, for example, from the viewpoint of desulfurization performance.
The upper limit of the amount of silver supported is not particularly limited, and can be, for example, 20% by mass or less.

(Other ingredients)
The second desulfurizing agent may contain other components other than zeolite and silver as necessary, as long as the effects of the present invention are not impaired.
Examples of the other components include a binder as a molding material. Examples of the binder include alumina, silica, and clay mineral.
The 2nd desulfurization agent may contain metals other than silver as an unavoidable component in the range which does not impair the effect of this invention.

~ Shape of second desulfurization agent ~
The shape of the second desulfurizing agent is not particularly limited and can be appropriately selected according to the purpose.
Examples of the shape of the second desulfurizing agent include granular shapes, columnar shapes (for example, columnar shapes), honeycomb shapes, and crushed shapes.
Among these, as the shape of the second desulfurizing agent, for example, from the viewpoint of cost, at least one shape selected from the group consisting of granular, columnar, and crushed is preferable, and the density and From the viewpoint of not containing fine powder, at least one shape selected from granular and columnar is more preferable.

-Method for producing second desulfurizing agent-
The method for producing the second desulfurizing agent is not particularly limited, and the second desulfurizing agent can be produced by adopting a known method for supporting silver on zeolite. Examples of a method for supporting silver on zeolite include an ion exchange method.

  A commercial item can be used as a 2nd desulfurization agent. Examples of commercially available products of the second desulfurizing agent include FKS-A (trade name, shape: granular, zeolite type: Y-type zeolite, supported amount of silver: 14% by mass relative to the total mass of the zeolite, JGC catalyst Kasei Co., Ltd.).

[Third desulfurization section]
The third desulfurization section includes a third desulfurization agent.
In the third desulfurization section, among the sulfur compounds that have not been removed by the first desulfurization agent, sulfur compounds that cannot be adsorbed by the second desulfurization agent are removed by the third desulfurization agent.

<Third desulfurizing agent>
The third desulfurizing agent includes activated carbon and a metal attached to the activated carbon, and the metal includes at least one selected from the group consisting of nickel, tungsten, and molybdenum. The metal preferably includes a combination of copper and at least one selected from the group consisting of nickel, tungsten, and molybdenum.
Since the third desulfurizing agent has the above-described configuration, among the sulfur compounds that have not been removed by the first desulfurizing agent, sulfur compounds that cannot be adsorbed by the second desulfurizing agent are efficiently adsorbed and removed. can do.
In addition, about the preferable activated carbon of a 3rd desulfurizing agent, since it is the same as that of the preferable activated carbon of a 1st desulfurizing agent, the description is abbreviate | omitted. In addition, when using activated carbon to which a metal including a combination of copper and at least one selected from the group consisting of nickel, tungsten, and molybdenum is attached as a desulfurizing agent, the same matters as the first desulfurizing agent are used. The description of the preferred configuration is omitted.

The amount of nickel to be added is, for example, preferably 1.0% by mass or more and 20.0% by mass or less, and 2.0% by mass or more and 15.0% by mass or less with respect to the total mass of the third desulfurizing agent. More preferably, it is 2.0 mass% or more and 8.0 mass% or less.
The amount of tungsten added is preferably, for example, 1.0% by mass or more and 20.0% by mass or less, and 2.0% by mass or more and 15.0% by mass or less with respect to the total mass of the third desulfurizing agent. More preferably, it is 2.0 mass% or more and 8.0 mass% or less.
The amount of molybdenum added is preferably, for example, 1.0% by mass or more and 20.0% by mass or less, and 2.0% by mass or more and 15.0% by mass or less with respect to the total mass of the third desulfurizing agent. More preferably, it is 2.0 mass% or more and 8.0 mass% or less.

≪Desulfurizer for fuel gas according to another embodiment≫
[Desulfurizer for fuel gas]
A fuel gas desulfurizer according to another embodiment of the present invention includes a first desulfurization section including a first desulfurization agent, and a second desulfurization agent disposed downstream of the first desulfurization section in the gas flow direction. A second desulfurization section, and a third desulfurization section that is disposed downstream of the second desulfurization section in the gas flow direction and includes a third desulfurization agent, wherein the first desulfurization agent is activated carbon. A metal adhering to the activated carbon, wherein the metal includes copper, the second desulfurizing agent includes zeolite supported on silver, and the third desulfurizing agent supports the silver. Adsorbability of carbonyl sulfide is higher than that of the obtained zeolite.
According to the fuel gas desulfurizer of another embodiment, as in the fuel gas desulfurizer of the above-described one embodiment, it is possible to efficiently adsorb and remove a plurality of types of sulfur compounds contained in the fuel gas, and Compared to a conventional desulfurizer using silver-supported zeolite, the amount of silver-supported zeolite can be reduced, and the desulfurizer can be downsized. In particular, even when LP gas is used as the fuel gas, the use of a third desulfurizing agent having excellent carbonyl sulfide adsorptivity makes it possible to efficiently reduce the amount of silver-supported zeolite and to efficiently produce sulfur compounds. Can be removed.
In addition, since the preferable structure of the 1st desulfurization part in 2nd embodiment and the 2nd desulfurization part is the same as the preferable structure of the 1st desulfurization part and the 2nd desulfurization part in one above-mentioned embodiment, Description is omitted.

[Third desulfurization section]
The third desulfurization section includes a third desulfurization agent having higher carbonyl sulfide adsorption than the zeolite on which silver is supported.
In the third desulfurization section, among the sulfur compounds not removed by the first desulfurizing agent, sulfur compounds containing carbonyl sulfide that cannot be adsorbed by the second desulfurizing agent are removed by the third desulfurizing agent.
Whether or not the adsorbability of carbonyl sulfide is higher than that of zeolite on which silver is supported with respect to a specific desulfurizing agent can be determined by, for example, the “-second desulfurizing agent amount setting” shown in Comparative Example 2 described later. When the sample gas is allowed to flow under the conditions, the determination may be made based on the magnitude of the COS adsorption amount in a specific desulfurizing agent and the COS adsorption amount in silver-supported zeolite.

<Third desulfurizing agent>
The third desulfurizing agent is not particularly limited as long as it is a desulfurizing agent having higher carbonyl sulfide adsorption than silver-supported zeolite.
The third desulfurizing agent includes, for example, activated carbon and a metal attached to the activated carbon, and the metal may include at least one selected from the group consisting of nickel, tungsten, and molybdenum. Preferably, it may contain a combination of copper and at least one selected from the group consisting of nickel, tungsten, and molybdenum. At this time, the preferred configuration of the third desulfurizing agent is the same as the preferred configuration of the first desulfurizing agent in one embodiment, and thus the description thereof is omitted.

[Use of fuel gas desulfurizer]
The fuel gas desulfurizer of one embodiment, other embodiments, etc. (this embodiment) is a desulfurizer that is applied to an application for removing a sulfur compound contained in a fuel gas used as a fuel. Contact with a fuel gas containing a sulfur compound in a temperature range of 0 ° C. to 60 ° C., and the sulfur compound in the fuel gas is removed by physically or chemically adsorbing the sulfur compound on the surface of the desulfurizing agent. It is a desulfurizer used for desulfurization of adsorptive desulfurization.

  Examples of the fuel gas containing a sulfur compound include city gas, LP gas, natural gas, digestion gas, and exhaust gas. The fuel gas desulfurizer of the present invention can be applied to any of these fuel gases. In particular, when LP gas containing a sulfur compound is used, the amount of silver-supported zeolite can be suitably reduced, which is useful.

The desulfurizer for fuel gas according to this embodiment includes hydrogen sulfide (H ₂ S), carbonyl sulfide (COS), mercaptans [methyl mercaptan (MM), ethyl mercaptan (EM), tert-butyl mercaptan contained in the fuel gas. (TBM, etc.), sulfides (dimethyl sulfide (DMS), diethyl sulfide (DES), dimethyl disulfide (DMDS), etc.), thiophenes (tetrahydrothiophene (THT), etc.) and other sulfur compounds are efficiently adsorbed and removed. In addition, the amount of silver-supported zeolite can be reduced and the size of the desulfurizer can be reduced compared to a conventional desulfurizer using a silver-supported zeolite. , Fuel cell using fuel gas such as city gas, LP gas, natural gas, digestion gas, exhaust gas It is suitable as a desulfurizer (that is, a cold adsorption desulfurizer) in a pretreatment stage in the system.
In addition, since the desulfurizer for fuel gas of these embodiments can reduce the amount of silver-supported zeolite, the desulfurizer in a domestic fuel cell system is required, in particular, to reduce the cost and size of the desulfurizer. And is preferably used.

[Manufacturing method of desulfurizer for fuel gas]
The fuel gas desulfurizer of the present embodiment can be manufactured, for example, by filling a predetermined container in order with a first desulfurizing agent, a second desulfurizing agent, and a third desulfurizing agent.
Examples of the material for the container include stainless steel (SUS) and resin.
Examples of the shape of the container include a cylindrical shape and a rectangular tube shape.
The packing density of the first desulfurizing agent, the second desulfurizing agent and the third desulfurizing agent in the container can be appropriately set in consideration of the adsorption amount of sulfur compounds contained in the fuel gas, pressure loss, and the like. .

  The fuel gas desulfurizer of the present embodiment may include a filter or the like for preventing the third desulfurization agent from scattering on the downstream side of the container in the gas flow direction.

[Fuel gas desulfurization method]
The fuel gas desulfurization method according to an embodiment of the present invention is a method for performing desulfurization by supplying fuel gas to the fuel gas desulfurizer of the present embodiment. For example, a fuel gas containing a sulfur compound in a temperature range of 0 ° C. to 60 ° C. is brought into contact with each desulfurization agent contained in the fuel gas desulfurizer of this embodiment, and the surface of each desulfurization agent is physically or chemically contacted. The sulfur compound in the fuel gas may be removed by adsorbing the sulfur compound.

[Fuel gas desulfurization system]
A fuel gas desulfurization system according to an embodiment of the present invention includes the fuel gas desulfurizer of the present embodiment and a fuel gas supply source that supplies fuel gas to the fuel gas desulfurizer.

[Fuel gas supply source]
The fuel gas supply source is a gas supply source that supplies fuel gas to the fuel gas desulfurizer of the present embodiment. Examples of the fuel gas include city gas, LP gas, natural gas, digestion gas, and exhaust gas.

〔Fuel cell〕
The fuel gas desulfurization system of this embodiment may include a fuel cell that generates power using the fuel gas desulfurized by the fuel gas desulfurizer. The fuel gas desulfurized in the fuel gas desulfurizer is reformed with steam, carbon dioxide, etc., and then supplied to the fuel cell, and hydrogen, carbon monoxide, etc. generated by reforming the fuel gas are used for power generation. It may be a configuration. Alternatively, the fuel gas desulfurized in the fuel gas desulfurizer, water vapor, carbon dioxide and the like are fuel cells (preferably a high-temperature fuel cell operating at about 600 ° C. to 800 ° C., more specifically, a solid The fuel is directly supplied to an oxide fuel cell, a molten carbonate fuel cell, etc.), and hydrogen, carbon monoxide, etc. generated by internal reforming of the fuel gas in the fuel cell are used for power generation. Also good.

[Hydrogen production equipment]
The fuel gas desulfurization system of this embodiment may include a hydrogen production apparatus that produces hydrogen using the fuel gas desulfurized by the fuel gas desulfurizer. For example, the fuel gas desulfurized by the fuel gas desulfurizer may be reformed by steam, carbon dioxide, etc. in a hydrogen production device to produce hydrogen.

Hereinafter, an example of the fuel gas desulfurization system of the present invention will be described with reference to the drawings.
FIG. 2 is a schematic configuration diagram illustrating a fuel gas desulfurization system according to an embodiment.
The fuel gas desulfurization system 50 according to an embodiment includes the fuel gas desulfurizer 1, the steam reformer 2, and the fuel cell 3 toward the downstream in the gas flow direction. First, fuel gas is supplied to the fuel gas desulfurizer 1 from a fuel gas supply source (not shown). The fuel gas supplied to the fuel gas desulfurizer 1 is desulfurized and then supplied to the steam reformer 2.

The fuel gas desulfurization system 50 includes a steam reformer 2 that generates steam and hydrogen monoxide by steam reforming the fuel gas desulfurized in the fuel gas desulfurizer 1. The steam reformer 2 is supplied with the fuel gas desulfurized by the fuel gas desulfurizer 1 and water vapor (H ₂ O). From the viewpoint of efficiently performing steam reforming, the steam reformer 2 may include, for example, a reforming catalyst and be heated to 600 ° C. to 800 ° C. In addition, since the fuel gas from which sulfur compounds have been removed by desulfurization is supplied to the steam reformer 2, when the steam reformer 2 includes a reforming catalyst, a reduction in catalyst function due to sulfur compound poisoning is suppressed. Is done.

The fuel gas desulfurization system 50 includes a fuel cell 3 that is supplied with hydrogen (H ₂ ), carbon monoxide (CO), and oxygen (O ₂ ) generated by the steam reformer 2 to generate power. More specifically, hydrogen and carbon monoxide generated in the steam reformer 2 are supplied to the anode (not shown) of the fuel cell 3, and oxygen is supplied to the cathode (not shown) of the fuel cell 3. Then, power generation is performed. At this time, since the sulfur compound in the fuel gas is removed by desulfurization, the function deterioration of the electrode catalyst due to poisoning of the sulfur compound in the fuel cell is suppressed.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples unless it exceeds the gist thereof.
In this example, in order to determine the breakthrough time at an early stage, the test was performed under the condition where the concentration and flow rate during the test were accelerated, and the test condition was different from the actual use condition.

In the following examples, tert-butyl mercaptan is represented as “TBM”, dimethyl sulfide is represented as “DMS”, hydrogen sulfide is represented as “H ₂ S”, and methyl mercaptan is represented as “MM”. Dimethyl disulfide is expressed as “DMDS”, tetrahydrothiophene is expressed as “THT”, and carbonyl sulfide is expressed as “COS”.

<Comparative Example 1>
[Production of first desulfurizing agent]
[Production Example 1]
19 parts by mass of copper nitrate trihydrate and 25 parts by mass of nickel nitrate hexahydrate were dissolved in 500 parts by mass of water to obtain an impregnation solution. The resulting impregnation solution, coconut shell activated carbon treated with an inorganic acid (trade name: particulate Shirasagi _{C 2X,} shape: cylindrical, specific surface ^{area: 1200m 2 / g~1500m 2 / g} , manufactured by Osaka Gas Chemicals Co.) 100 parts by mass were immersed for 5 minutes. The immersed coconut shell activated carbon was placed in a flask provided in a rotary evaporator (model number: N1110 type, manufactured by Tokyo Rika Kikai Co., Ltd.). The soaked coconut shell activated carbon was dried for 120 minutes under reduced pressure at 50 ° C. so as not to bump when the flask was rotated and stirred. The soaked coconut shell activated carbon that has been dried from the flask is taken out, placed in a hot air circulating dryer (model number: FS-60W, manufactured by Tokyo Glass Instrument Co., Ltd.), and baked at a calcination temperature of 150 ° C. for 15 hours under air flow. As a result, a metal-impregnated charcoal (that is, a desulfurizing agent) in which copper and nickel were impregnated with coconut shell activated carbon was obtained. The obtained metal-impregnated charcoal was crushed using an agate mortar and then sized through a sieve having an opening of 0.35 μm to 0.75 μm to obtain a first desulfurizing agent.
The amounts of copper and nickel attached to the first desulfurizing agent were measured by ICP emission spectroscopic analysis using Optima 8000 (product name) manufactured by Perkin-Elmer, and the total mass of the first desulfurizing agent was measured. And 3.3% by mass and 3.1% by mass, respectively. Further, the ratio of the amount of nickel added to the amount of copper added in the first desulfurizing agent (the amount of nickel attached / the amount of copper attached) is 0.94 on a mass basis.

[Performance evaluation of first desulfurizing agent]
-Production of desulfurizer for evaluation test-
A desulfurizer for evaluation test was produced using the first desulfurizing agent obtained above. As shown in FIG. 3, a desulfurizing agent 200 was filled in a cylindrical tube 100 (inner diameter: 8.0 mm) so that the packed bed height was 38 mm. The filling amount of the desulfurizing agent is about 2.0 cm ³ . In addition, the cylindrical tube 100 has the eye plate 300 in the exit part.

-Measurement of adsorption amount of sulfur compounds-
The evaluation test desulfurizer produced above was placed in a thermostatic bath, and the interior of the bath was kept at 25 ° C. And the test gas which added the sulfur compound of the composition shown in following Table 1 to the desulfurized city gas 13A was flowed in the desulfurizer for evaluation tests at a flow rate of 1.0 L / min. Note that the dew point temperature of the test gas is −60 ° C. The test gas flows in the direction of the arrow shown in FIG.

The test gas was allowed to flow until the breakthrough point of all the sulfur compounds (breakthrough criterion: 28.6 mg / m ³ ) was confirmed. Then, the amount of adsorption of each sulfur compound to the desulfurization agent is calculated from the time until the breakthrough point of each sulfur compound is confirmed after flowing the test gas, the flow rate of the test gas, and the composition of the test gas. did.
The breakthrough point of the sulfur compound was confirmed every 3 hours by collecting the gas discharged from the outlet of the desulfurizer for evaluation test and detecting the peak attributed to each sulfur compound using gas chromatography. .
Moreover, the measurement conditions of gas chromatography are as follows.

(Measurement condition)
Gas chromatography system: GC-2014A (model number) manufactured by Shimadzu Access Co., Ltd.
Detector: Hydrogen flame ionization detector Analytical column: Shimalite 80/100 AW-AMDS-ST (trade name, 4.1 m × 3.2 mm ID, manufactured by Shinwa Chemical Co., Ltd.)
Injection volume: 3mL
Column temperature: 170 ° C

As a representative, the measurement results of the adsorption amounts of TBM, DMDS, and COS are shown in Table 2 below.
In addition, it means that a desulfurization agent is excellent in the adsorption capacity of a sulfur compound, so that the value of adsorption amount of 3 types total of TBM, DMDS, and COS is high.

  In Table 2, the value of “adsorption amount” is obtained by dividing the amount of sulfur compound adsorbed on the first desulfurizing agent by the breakthrough point by the mass of the first desulfurizing agent before adsorption. A value (unit: mass% S) converted to elemental sulfur is shown (the same applies hereinafter).

[Design of desulfurizer]
-First desulfurizing agent amount setting-
Based on the results of the TBM adsorption amount shown in Table 2, the amount of the first desulfurizing agent was set.
More specifically, the desulfurized city gas ^{13A, 7.0mg / m 3 ~14.0mg /} m 3 of ^{TBM, 1.4mg / m 3 ~7.0mg /} m 3 of DMDS, and 0.2 mg / When the sample gas to which COS of m ^{3 to} 0.7 mg / m ³ is added is flowed so that the flow gas amount is 5000 m ³ , all of the TBM contained in the sample gas can be adsorbed. The amount of 1 desulfurizing agent was calculated according to the following formula (1) based on the results of the adsorption amount of TBM shown in Table 2.
Amount of first desulfurizing agent [cm ³ ] = concentration of TBM in the test gas [mg / m ³ ] × circulated gas amount of the test gas [m ³ ] ÷ (adsorption amount of TBM shown in Table 2 [mass % S] / 100) ÷ 1000 ÷ specific gravity of the first desulfurizing agent [g / cm ³ ] (1)

With the amount of the first desulfurizing agent set as described above, the amounts of DMDS and COS that could not be adsorbed were calculated according to the following formulas (2) and (3), respectively. In the following formulas (2) and (3), the amount [cm ³ ] of the first desulfurizing agent calculated above was used in terms of g (gram) units. The conversion formula is shown in Formula (1A).
Amount [g] of first desulfurizing agent = amount of first desulfurizing agent [cm ³ ] × specific gravity of first desulfurizing agent [g / cm ³ ] (1A)
DMDS amount [mg] = concentration of DMDS in the test gas [mg / m ³ ] × flow amount of test gas [m ³ ] −the amount of first desulfurization agent [g] × 1000 × (Table 2) DMDS adsorption amount [mass% S] / 100) shown in formula (2)
Amount of COS [mg] = Concentration of COS in the test gas [mg / m ³ ] × Amount of flowing gas of the test gas [m ³ ] −Amount of the first desulfurizing agent [g] × 1000 × (Table 2 COS adsorption amount [mass% S] / 100) shown in formula (3)

-Setting the amount of the second desulfurizing agent-
As a second desulfurizing agent, a commercially available silver-supported zeolite (trade name: FKS-A, shape: granular, type of zeolite: Y-type zeolite, supported amount of silver: 14% by mass relative to the total mass of the zeolite, JGC catalyst Kasei Chemical Co., Ltd.) was used to produce a desulfurizer for evaluation tests. As shown in FIG. 3, a desulfurizing agent 200 was filled in a cylindrical tube 100 (inner diameter: 8.0 mm) so that the packed bed height was 38 mm. The filling amount of the desulfurizing agent is about 2 cm ³ . In addition, the cylindrical tube 100 has the eye plate 300 in the exit part.
The evaluation test desulfurizer produced above was placed in a thermostatic bath, and the interior of the bath was kept at 25 ° C. And the test gas which added the sulfur compound of the composition shown to the following Table 3 to the desulfurized city gas 13A was flowed in the desulfurizer for evaluation tests at a flow rate of 1.0 L / min. Note that the dew point temperature of the test gas is −60 ° C. The test gas flows in the direction of the arrow shown in FIG.

The test gas was allowed to flow until the breakthrough point of all the sulfur compounds (breakthrough criterion: 28.6 mg / m ³ ) was confirmed. Then, the adsorption time of each sulfur compound to the second desulfurizing agent from the flow of the test gas until the breakthrough point of each sulfur compound is confirmed, the flow rate of the test gas, and the composition of the test gas. The amount was calculated.
The breakthrough point of the sulfur compound was confirmed every 3 hours by collecting the gas discharged from the outlet of the desulfurizer for evaluation test and detecting the peak attributed to each sulfur compound using gas chromatography. . The measurement conditions for gas chromatography are the same as the measurement conditions for measuring the adsorption amount of the sulfur compound.
Table 4 below shows the measurement results of the adsorption amounts of DMDS and COS in the second desulfurizing agent.

  In Table 4, the value of “adsorption amount” is obtained by dividing the amount of sulfur compound adsorbed on the second desulfurization agent by the breakthrough point by the mass of the desulfurization agent before adsorption, and converting the obtained value into elemental sulfur. The converted value (unit: mass% S) is shown (hereinafter the same).

The amount of DMDS and COS adsorbed in the second desulfurizing agent shown in Table 4 and the amount set based on the TBM adsorbed amount in the first desulfurizing agent shown in Table 2 calculated above. The amount of the second desulfurizing agent was set based on the amount of DMDS and COS that could not be adsorbed by the first desulfurizing agent. Specifically, the setting was made as follows.
First, the amount of the second desulfurizing agent necessary for the adsorption of DMDS and COS that cannot be adsorbed by the amount of the first desulfurizing agent set above is determined according to the following equations (4) and (5), respectively. Calculated.
Amount of second desulfurization agent necessary for DMDS adsorption [cm ³ ] = DMDS amount calculated by Equation (2) [mg] ÷ (DMDS adsorption amount [mass% S] / 100 shown in Table 4) ÷ 1000 ÷ specific gravity [g / cm ³ ] of the second desulfurization agent (4)
Amount of second desulfurization agent required for COS adsorption [cm ³ ] = COS amount calculated by Equation (3) [mg] ÷ (COS adsorption amount [mass% S] / 100 shown in Table 4) ÷ 1000 ÷ specific gravity [g / cm ³ ] of the second desulfurization agent (5)

Of the amount of the second desulfurizing agent calculated by the equations (4) and (5), a larger amount was set as the amount of the second desulfurizing agent.
The amount of the second desulfurizing agent thus set is an amount capable of adsorbing all DMDS and COS that cannot be adsorbed by the first desulfurizing agent.

  The configurations of the desulfurizer of Comparative Example 1 designed based on the above results are shown in Table 9 and Table 10 below, and FIG.

<Comparative example 2>
In the same manner as in Comparative Example 1, a first desulfurizing agent was produced, and an evaluation test desulfurizer was produced using the produced first desulfurizing agent.

-Measurement of adsorption amount of sulfur compounds-
The evaluation test desulfurizer produced above was placed in a thermostatic bath, and the interior of the bath was kept at 25 ° C. Then, in the desulfurizer for evaluation test, a test gas obtained by adding a sulfur compound having a composition shown in Table 5 below to desulfurized LP gas (propane about 95% by volume, butane about 5% by volume) is 1.0 L / Flowed at a flow rate of min. Note that the dew point temperature of the test gas is −60 ° C. The test gas flows in the direction of the arrow shown in FIG.

The test gas was allowed to flow until the breakthrough point of all the sulfur compounds (breakthrough criterion: 28.6 mg / m ³ ) was confirmed. Then, the adsorption of each sulfur compound to the first desulfurizing agent from the flow of the test gas until the breakthrough point of each sulfur compound is confirmed, the flow rate of the test gas, and the composition of the test gas. The amount was calculated.
The breakthrough point of the sulfur compound was confirmed every 3 hours by collecting the gas discharged from the outlet of the desulfurizer for evaluation test and detecting the peak attributed to each sulfur compound using gas chromatography. . The measurement conditions for gas chromatography are the same as the measurement conditions for measuring the adsorption amount of the sulfur compound.
The measurement results of the amount of adsorption of TBM, DMDS, and COS in the first desulfurizing agent are shown in Table 6 below.

[Design of desulfurizer]
-First desulfurizing agent amount setting-
Based on the results of the TBM adsorption amount shown in Table 6, the amount of the first desulfurizing agent was set.
More specifically, the desulfurized of LP ^{gas, 5.0mg / m 3 ~10.0mg / m} 3 of ^{TBM, 5.0mg / m 3 ~10.0mg /} m 3 of DMDS, and 5.0 mg / m ^{The first} gas capable of adsorbing all of the TBM contained in the test gas when the test gas to which COS of ^{3 to} 10.0 mg / m ³ is added is flowed so that the flow gas amount becomes 5000 m ³ . Based on the result of the TBM adsorption amount shown in Table 6, the amount of the desulfurizing agent was replaced with “the TBM adsorption amount shown in Table 6” as “the TBM adsorption amount shown in Table 6”. ).

  The amount of DMDS and COS that could not be adsorbed with the amount of the first desulfurizing agent set above was replaced with “DMDS adsorption amount shown in Table 2” and “DMDS adsorption amount shown in Table 6”, respectively. The calculation was performed using the above formula (2) and the above formula (3) in which “the COS adsorption amount shown in Table 2” was replaced with “the COS adsorption amount shown in Table 6”.

-Setting the amount of the second desulfurizing agent-
A desulfurizer for evaluation test was produced in the same manner as in Comparative Example 1 using the above silver-supported zeolite as the second desulfurizing agent.
The evaluation test desulfurizer produced above was placed in a thermostatic bath, and the interior of the bath was kept at 25 ° C. And the test gas which added the sulfur compound of the composition shown in following Table 7 to the desulfurized LP gas was flowed in the desulfurizer for evaluation tests at a flow rate of 1.0 L / min. Note that the dew point temperature of the test gas is −60 ° C. The test gas flows in the direction of the arrow shown in FIG.

The test gas was allowed to flow until the breakthrough point of all the sulfur compounds (breakthrough criterion: 28.6 mg / m ³ ) was confirmed. Then, the adsorption time of each sulfur compound to the second desulfurizing agent from the flow of the test gas until the breakthrough point of each sulfur compound is confirmed, the flow rate of the test gas, and the composition of the test gas. The amount was calculated.
The breakthrough point of the sulfur compound was confirmed every 3 hours by collecting the gas discharged from the outlet of the desulfurizer for evaluation test and detecting the peak attributed to each sulfur compound using gas chromatography. . The measurement conditions for gas chromatography are the same as the measurement conditions for measuring the adsorption amount of the sulfur compound.
Table 8 below shows the measurement results of the adsorption amounts of DMDS and COS in the second desulfurization agent.

The amount of DMDS and COS adsorbed in the second desulfurizing agent shown in Table 8 and the amount set based on the result of the TBM adsorbing amount in the first desulfurizing agent shown in Table 6 calculated above. The amount of the second desulfurizing agent was set based on the amount of DMDS and COS that could not be adsorbed by the first desulfurizing agent. Specifically, the setting was made as follows.
First, the amount of the second desulfurizing agent necessary for the adsorption of DMDS and COS that cannot be adsorbed by the amount of the first desulfurizing agent set as described above, the “adsorption amount of DMDS shown in Table 4”, and The above equation (4) replaced with “DMDS adsorption amount” and “COS adsorption amount shown in Table 4” with “COS adsorption amount shown in Table 8” above. Used to calculate.

Of the amount of the second desulfurizing agent calculated by the equations (4) and (5), a larger amount, that is, the amount of the second desulfurizing agent calculated by the equation (5) is used as the amount of the second desulfurizing agent. Set as.
The amount of the second desulfurizing agent thus set is an amount capable of adsorbing all DMDS and COS that cannot be adsorbed by the first desulfurizing agent.

  The configuration of the desulfurizer of Comparative Example 2 designed based on the above results is shown in Table 9 and Table 10 below and FIG.

<Example 1>
-First desulfurizing agent amount setting-
First, in the same manner as in Comparative Example 2, the amount of the first desulfurizing agent was set. That is, the amount of the first desulfurizing agent capable of adsorbing all of the TBM contained in the test gas described in Comparative Example 1 was defined as the amount of the first desulfurizing agent in Example 1.

-Setting the amount of the second desulfurizing agent-
Next, among the amounts of the second desulfurizing agent calculated by the equations (4) and (5) in Comparative Example 2, the smaller amount, that is, the amount of the second desulfurizing agent calculated by the equation (4) is used. The amount of the second desulfurizing agent was set.
The amount of the second desulfurizing agent thus set is not an amount capable of adsorbing all of the COS that cannot be adsorbed by the first desulfurizing agent, but DMDS that cannot be adsorbed by the first desulfurizing agent. Is an amount capable of adsorbing all of the above.

-Setting the amount of the third desulfurizing agent-
In the same manner as in Comparative Example 1, a first desulfurizing agent was produced, and an evaluation test desulfurizer was produced using the produced first desulfurizing agent as a third desulfurizing agent.
The evaluation test desulfurizer produced above was placed in a thermostatic bath, and the interior of the bath was kept at 25 ° C. Then, the evaluation test desulfurizer within the desulfurized of LP ^gas, flowed test gas added to COS of 5.0mg / ^{m 3} ~10.0mg / m 3 at a flow rate of 1.0 L / min. Note that the dew point temperature of the test gas is −60 ° C. The test gas flows in the direction of the arrow shown in FIG.

The test gas was allowed to flow until a breakthrough point of the sulfur compound (COS) (breakthrough standard: 28.6 mg / m ³ ) was confirmed. Then, the amount of adsorption of the sulfur compound to the third desulfurizing agent is calculated from the time until the breakthrough point of the sulfur compound is confirmed after flowing the test gas, the flow rate of the test gas, and the composition of the test gas. Calculated.
The breakthrough point of the sulfur compound was confirmed every 3 hours by collecting the gas discharged from the outlet of the desulfurizer for evaluation test and detecting the peak attributed to each sulfur compound using gas chromatography. . The measurement conditions for gas chromatography are the same as the measurement conditions for measuring the adsorption amount of the sulfur compound.
The adsorption amount of COS in the third desulfurizing agent was 0.58 mass% S.

An amount of the first desulfurizing agent set based on the result of the adsorption amount of COS in the third desulfurizing agent and the result of the adsorption amount of TBM in the first desulfurizing agent shown in Table 6 calculated above, and The amount of the third desulfurizing agent was set based on the amount of COS that could not be adsorbed by the amount of the second desulfurizing agent set based on the result of the adsorption amount of DMDS in the second desulfurizing agent shown in Table 8. . Specifically, the setting was made as follows. First, the amount of COS that could not be adsorbed by the amounts of the first and second desulfurizing agents set above was calculated according to the following formula (6). In the following equation (6), the amount of the first desulfurizing agent in an amount [cm ^3] and a second desulfurization agent calculated in the [cm ^3], respectively, in terms of g (grams) units Using. The conversion formulas are the above formula (1A) and the following formula (1B).
Amount of second desulfurizing agent [g] = Amount of second desulfurizing agent [cm ³ ] × Specific gravity of second desulfurizing agent [g / cm ³ ] Formula (2A)
Amount of COS [mg] = Concentration of COS in test gas [mg / m ³ ] × Amount of flowing gas of test gas [m ³ ] −Amount of first desulfurizing agent [g] × 1000 × (Table 6 COS adsorption amount [mass% S] / 100) -second desulfurizing agent amount [g] × 1000 × (COS adsorption amount [mass% S] / 100 shown in Table 8) Formula ( 6)

Based on the result of the amount of COS adsorbed in the third desulfurizing agent and the amount of COS that cannot be adsorbed by the amount of the first desulfurizing agent and the second desulfurizing agent set as described above, The amount was set. Specifically, the setting was made as follows.
First, the amount of the third desulfurizing agent necessary for the adsorption of COS that cannot be adsorbed by the amounts of the first desulfurizing agent and the second desulfurizing agent set above was calculated according to the following formula (7). .
Amount of third desulfurization agent necessary for COS adsorption [cm ³ ] = COS amount calculated by Equation (6) ÷ mg (COS adsorption amount shown in Table 8 [mass% S] / 100) ÷ 1000 ÷ specific gravity [g / cm ³ ] of the third desulfurizing agent (here, the same as the first desulfurizing agent) (7)

The amount of the third desulfurizing agent calculated by the equation (7) was set as the amount of the third desulfurizing agent.
The amount of the third desulfurizing agent thus set is an amount capable of adsorbing all COS that cannot be adsorbed by the first desulfurizing agent and the second desulfurizing agent.

  The structure of the desulfurizer of Example 1 designed based on the above result is shown in the following Table 9 and Table 10, and FIG.

As shown in Table 9 and Table 10 and FIG. 4, the desulfurizer of Comparative Example 2 that supplied LP gas as the gas type is necessary as compared with the desulfurizer of Comparative Example 1 that supplied city gas 13A as the gas type. The amount of such a desulfurizing agent was very large, and particularly a large amount of silver-supported zeolite was required.
On the other hand, when the desulfurizer is configured as in Example 1, the amount of desulfurizing agent required can be reduced even when LP gas is supplied as a gas species. We were able to greatly reduce the amount used.
From these results, according to the present invention, the amount of expensive silver-carrying zeolite can be reduced and the amount of the entire desulfurizing agent can be reduced, thereby reducing the cost and size of the desulfurizer. In particular, it is useful when using a gas containing a large amount of a sulfur compound such as LP gas and containing a hydrocarbon component (a hydrocarbon component having a large number of carbon atoms) that inhibits desulfurization. it is conceivable that.

<Experimental example 1>
[Production of desulfurizing agent A]
[Production Example 2]
Metal-impregnated charcoal in which copper is impregnated with coconut shell activated carbon (ie, with the exception of having obtained an impregnating solution by dissolving 38 parts by mass of copper nitrate trihydrate in 500 parts by mass of water) A desulfurizing agent). The obtained metal-impregnated charcoal was crushed and sized in the same manner as in Production Example 1 to obtain a desulfurizing agent A.
In addition, when the adhesion amount of copper in the desulfurizing agent A was measured by the same method as in Production Example 1, it was 6.8% by mass relative to the total mass of the desulfurizing agent.
Next, a desulfurizer for evaluation test was produced in the same manner as in Comparative Example 1, and the adsorption amount of the sulfur compound was measured under the same conditions as in Comparative Example 1. As a representative, the measurement results of the adsorption amounts of TBM, DMDS and COS are shown in Table 11 below.

<Experimental example 2>
[Production of desulfurizing agent B]
[Production Example 3]
In the same manner as in Production Example 1 except that 50 parts by mass of nickel nitrate hexahydrate was dissolved in 500 parts by mass of water to obtain an impregnation solution, a metal-impregnated carbon in which nickel was impregnated with coconut shell activated carbon (ie, A desulfurizing agent). The obtained metal-impregnated charcoal was crushed and sized in the same manner as in Production Example 1 to obtain a desulfurizing agent B.
In addition, when the adhesion amount of nickel in the desulfurizing agent B was measured by the same method as in Production Example 1, it was 6.7% by mass with respect to the total mass of the desulfurizing agent.
Next, a desulfurizer for evaluation test was produced in the same manner as in Comparative Example 1, and the adsorption amount of the sulfur compound was measured under the same conditions as in Comparative Example 1. As a representative, the measurement results of the adsorption amounts of TBM, DMDS and COS are shown in Table 11 below.

  As shown in Table 11, Cu-added activated carbon was particularly excellent in the amount of adsorption of TBM, and Ni-added activated carbon was particularly excellent in the amount of adsorption of COS.

  DESCRIPTION OF SYMBOLS 1 ... Fuel gas desulfurizer, 2 ... Steam reformer, 3 ... Fuel cell, 10 ... 1st desulfurization part, 20 ... 2nd desulfurization part, 30 ... 3rd desulfurization part, 50 ... Fuel gas desulfurization system

Claims (11)

A first desulfurization section comprising a first desulfurization agent, a second desulfurization section disposed downstream of the first desulfurization section in the gas flow direction, and comprising a second desulfurization agent, and the second desulfurization section. A third desulfurization section that is disposed downstream of the gas flow direction and includes a third desulfurization agent,
The first desulfurizing agent and the third desulfurizing agent include activated carbon and a metal attached to the activated carbon,
The metal contained in the first desulfurizing agent includes copper,
The metal contained in the third desulfurizing agent includes at least one selected from the group consisting of nickel, tungsten, and molybdenum,
The second desulfurizing agent is a fuel gas desulfurizer including silver-supported zeolite.   The metal contained in the first desulfurizing agent and the third desulfurizing agent each independently includes copper and at least one selected from the group consisting of nickel, tungsten, and molybdenum. The desulfurizer for fuel gas as described. The first desulfurizing agent and the third desulfurizing agent include copper and nickel as the metal,
3. The fuel gas desulfurizer according to claim 2, wherein a ratio of the nickel deposition amount to the copper deposition amount is independently in a range of 0.20 to 2.70 on a mass basis. The first desulfurizing agent and the third desulfurizing agent include copper and tungsten as the metal,
3. The fuel gas desulfurizer according to claim 2, wherein a ratio of the tungsten deposition amount to the copper deposition amount is independently in a range of 0.10 to 0.60 on a mass basis. The first desulfurizing agent and the third desulfurizing agent include copper and molybdenum as the metal,
3. The fuel gas desulfurizer according to claim 2, wherein a ratio of the molybdenum deposition amount to the copper deposition amount is independently in a range of 0.15 to 2.00 on a mass basis. A first desulfurization section comprising a first desulfurization agent, a second desulfurization section disposed downstream of the first desulfurization section in the gas flow direction, and comprising a second desulfurization agent, and the second desulfurization section. A third desulfurization section that is disposed downstream of the gas flow direction and includes a third desulfurization agent,
The first desulfurizing agent includes activated carbon and a metal attached to the activated carbon,
The metal includes copper;
The second desulfurizing agent includes a zeolite on which silver is supported,
The third desulfurizing agent is a fuel gas desulfurizer having higher carbonyl sulfide adsorption than the zeolite on which the silver is supported.   The desulfurizer for fuel gas according to claim 6, wherein the metal includes copper and at least one selected from the group consisting of nickel, tungsten, and molybdenum. A desulfurizer for fuel gas according to any one of claims 1 to 7,
A fuel gas supply source for supplying fuel gas to the fuel gas desulfurizer;
A fuel gas desulfurization system.   The fuel gas desulfurization system according to claim 8, wherein the fuel gas is city gas, liquefied petroleum gas, natural gas, digestion gas, or exhaust gas.   At least a fuel cell that generates power using the fuel gas desulfurized by the fuel gas desulfurizer, and a hydrogen production apparatus that produces hydrogen using the fuel gas desulfurized by the fuel gas desulfurizer The fuel gas desulfurization system according to claim 8 or 9, further comprising one.   A fuel gas desulfurization method for supplying a fuel gas to the fuel gas desulfurizer according to any one of claims 1 to 7 and performing desulfurization.