JP2019003903A - Fuel cell system - Google Patents

Abstract

To provide a fuel cell system that efficiently deodorizes hydrogen gas odorized with an odorant.SOLUTION: A fuel cell system includes a fuel cell that generates electricity by distributing hydrogen gas odorized by an odorant other than a sulfur compound, a deodorizing unit that is one of an adsorption unit disposed one of upstream and downstream of the fuel cell and provided with an adsorbent for adsorbing the odorant and an odor eliminating unit that reacts the odoriferizable odorant with the hydrogen gas due to reaction with the hydrogen gas to form an odorless component, and a depressurizing unit that is disposed upstream of the fuel cell and depressurizes the hydrogen gas.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a fuel cell system.

  Specific moves toward the realization of a hydrogen society are progressing in the national, local governments and private companies. For example, a hydrogen station for fuel cell vehicles has been built, and fuel cells for home use and business use have been developed.

  A fuel cell generates electric power with high efficiency by an electrochemical reaction. In fuel cells, hydrogen obtained by reforming hydrocarbon fuels such as city gas, liquefied petroleum (LP) gas, and natural gas is generally used. In the future hydrogen society, since hydrogen is supplied as fuel through a conduit, a reformer for reforming hydrocarbon fuel becomes unnecessary, and a fuel cell is a device that can effectively use hydrogen supplied as fuel. it is conceivable that.

By the way, if the fuel gas leaks from the conduit, it may lead to an accident such as a fire. Therefore, it is necessary to have a mechanism that can detect the fuel gas leak and prevent the accident. As a countermeasure for this, a technique for odorizing fuel gas is known so that it can be detected even if fuel gas leaks (see, for example, Patent Document 1).
Moreover, as a typical odorant in city gas, a mixture of t-butyl mercaptan (TBM) and dimethyl sulfide (DMS) can be used. Further, a method of odorizing hydrogen only with cyclohexene has been studied (for example, see Non-Patent Document 1).

JP 2014-46250 A

Fiscal 2011-2014 Empirical research using Kitakyushu Hydrogen Town, Internet search <http://hysut.or.jp/archive/business/2011/02/index.html>

  When hydrogen is used as the fuel gas and the hydrogen is odorized, if the odorant remains in the exhaust gas (off-gas) after using hydrogen, there is a possibility that it may be mistaken for hydrogen leakage. Therefore, it is preferable to release the odorant in the exhaust gas to the atmosphere after reducing it to a concentration lower than a human detectable level.

  An object of one embodiment of the present invention is to provide a fuel cell system that efficiently deodorizes hydrogen gas odorized with an odorant.

Specific means for solving the above problems include the following embodiments.
<1> A fuel cell that generates power by circulating hydrogen gas odorized by an odorant other than a sulfur compound, and an adsorption that is arranged at least one of upstream and downstream of the fuel cell and adsorbs the odorant. An adsorbing part provided with an agent, a deodorizing part that is at least one of a deodorizing part that reacts with the hydrogen gas to produce an odorless component that can be deodorized by reaction with the hydrogen gas, and the fuel cell. A fuel cell system, comprising: a decompression unit disposed upstream and decompressing the hydrogen gas.
<2> The fuel cell system according to <1>, wherein the deodorizing unit is disposed upstream of the decompression unit.
<3> The fuel cell system according to <1> or <2>, in which the deodorizing unit is disposed downstream of the fuel cell.
<4> The deodorization unit disposed downstream of the fuel cell includes at least the non-bromide unit, and unreacted hydrogen gas is supplied to the deodorization unit disposed downstream of the fuel cell in the fuel cell. The fuel cell system according to <3>, wherein the fuel cell is operated as described above.
<5> The fuel cell system according to any one of <1> to <4>, wherein the deodorizing unit includes at least the adsorbing unit, and the adsorbent includes at least one of activated carbon and activated carbon to which a metal is attached. .
<6> The fuel cell system according to any one of <1> to <5>, wherein the adsorbent includes activated carbon to which a metal is attached.
<7> The deodorizing unit is disposed upstream and downstream of the fuel cell,
Switching capable of switching the gas flow path so that the gas flowing through the system is supplied to at least one of the deodorizing unit disposed upstream of the fuel cell and the deodorizing unit disposed downstream of the fuel cell. The fuel cell system according to any one of <1> to <6>, further including a unit.
<8> A control unit that controls switching of the switching unit according to the output of the fuel cell,
The control unit controls the switching of the switching unit when the output of the fuel cell becomes a predetermined value or less, so that the hydrogen odorized by the odorant that is a gas circulating in the system <7> The fuel cell system according to <7>, wherein the gas flow path is switched so that the gas is supplied to the deodorization unit disposed upstream of the fuel cell.

  According to one aspect of the present invention, it is possible to provide a fuel cell system that efficiently deodorizes hydrogen gas odorized with an odorant.

It is a figure which shows the specific structure 1 of the fuel cell system of this embodiment. It is a figure which shows the specific structure 2 of the fuel cell system of this embodiment. It is a figure which shows the specific structure 3 of the fuel cell system of this embodiment.

  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 specification, a numerical range indicated using “to” means a range including the numerical values described before and after “to” as a minimum value and a maximum value, respectively.
In the numerical ranges described stepwise in this specification, 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 range. Good. Further, in the numerical ranges described in this specification, the upper limit value or the lower limit value of the numerical range may be replaced with the values shown in the examples.

[Fuel cell system]
A fuel cell system according to an embodiment of the present invention is disposed in a fuel cell that generates power by circulating hydrogen gas odorized by an odorant other than a sulfur compound, and at least one of upstream and downstream of the fuel cell. And at least one of an adsorbing part comprising an adsorbent that adsorbs the odorant and a odorless part that reacts with the hydrogen gas an odorant that can be deodorized by reaction with the hydrogen gas. And a depressurization unit that is disposed upstream of the fuel cell and depressurizes the hydrogen gas. By providing the deodorization part which is at least one of an adsorption part and a non-bromide part in at least one of the upstream and downstream of a fuel cell, the hydrogen gas odorized with the odorant can be efficiently deodorized.

As the hydrogen gas, high-purity hydrogen gas, for example, hydrogen gas having a purity of 99% or more may be used. Examples of the high purity hydrogen gas include hydrogen gas derived from liquid hydrogen, purified hydrocarbon reforming, water electrolysis and the like.
In addition, the fuel cell system of the present embodiment preferably has a configuration that does not include a reformer that reforms hydrocarbon gas to generate hydrogen. This eliminates the need for a reformer, a device for removing carbon monoxide generated by the reforming, and the like, and the fuel cell system can be reduced in size and simplified.

(Fuel cell)
The fuel cell system of this embodiment includes a fuel cell that generates power using hydrogen gas. The fuel cell may be, for example, a fuel cell including a cathode (air electrode), an electrolyte and an anode (fuel electrode), or a fuel cell stack in which a plurality of fuel cells are stacked. The cathode is an electrode to which a gas containing oxygen such as air is supplied, and the anode is an electrode to which a gas containing hydrogen is supplied. Conventionally known cathodes, electrolytes and anodes may be used according to the type of fuel cell.

  The type of the fuel cell is not particularly limited, and examples thereof include a polymer electrolyte fuel cell (PEFC), a phosphoric acid fuel cell (PAFC), a molten carbonate fuel cell (MCFC), and a solid oxide fuel cell ( SOFC).

  When a polymer electrolyte fuel cell (PEFC), a phosphoric acid fuel cell (PAFC) or the like is used as a fuel cell, generally, hydrogen supplied to the anode moves as protons in the electrolyte to generate oxygen and oxygen on the cathode side. Power is generated by reacting and moving electrons from the anode to the cathode. Further, water (water vapor) generated by power generation is discharged from the cathode side as cathode offgas together with unreacted oxygen, and unreacted hydrogen is discharged from the anode side as anode offgas.

  When a molten carbonate fuel cell (MCFC), a solid oxide fuel cell (SOFC), or the like is used as the fuel cell, oxygen and carbon dioxide or oxygen supplied to the cathode is generally carbonate ion or oxygen, respectively. Electricity is generated by moving through the electrolyte as ions, reacting with hydrogen on the anode side, and moving electrons from the anode to the cathode. Further, water (water vapor) generated by power generation is discharged from the anode side as an anode off gas together with unreacted hydrogen, and unreacted oxygen is discharged from the cathode side as a cathode off gas.

  When the deodorizing part mentioned later is not arrange | positioned upstream of a fuel cell, it becomes the structure by which the odorant which smells hydrogen gas is supplied to a fuel cell with hydrogen gas. At this time, as described later, when an odorant other than a sulfur compound is used, particularly when a hydrocarbon odorant such as cyclohexene is used, poisoning of the fuel cell electrode catalyst by the odorant is suppressed. Therefore, adverse effects such as a decrease in the output of the fuel cell tend to be suppressed. In addition, when the odorant which odorizes hydrogen gas is supplied to a fuel cell with hydrogen gas, an odorant is discharged | emitted from the anode side as anode offgas.

(Deodorization part)
The fuel cell system of the present embodiment includes an adsorbing portion that is disposed at least one of the upstream and downstream sides of the fuel cell and includes an adsorbent that adsorbs an odorant other than a sulfur compound that odorizes hydrogen gas, and an odorant. It is provided with a deodorizing part which is at least one of a non-bromide part which reacts with hydrogen gas to make it an odorless component. The deodorizing unit may be disposed either upstream or downstream of the fuel cell, or may be disposed both upstream and downstream of the fuel cell.

  The adsorbing part is not particularly limited as long as it has an adsorbent that adsorbs an odorant that odorizes hydrogen gas. The adsorbent may be configured to adsorb the odorant that odorizes the hydrogen gas supplied to the adsorption unit, and may be appropriately selected according to the type of the odorant.

  As the adsorbent, since it has excellent adsorption performance of the odorant and is inexpensive, it preferably contains at least one of activated carbon and activated carbon to which a metal is attached. Since the adsorption performance of the odorant is excellent, the metal is attached. Preferably, the activated carbon is included.

  As the activated carbon, activated carbon that is usually used in the desulfurization field, the deodorization field, or the like 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, or the surface of the activated carbon is hydrophilized. Therefore, the adsorption performance of the odorant is further improved, and the degree of dispersion of the metal attached to the activated carbon tends to 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.

For example, the metal attached to the activated carbon preferably includes copper, and more preferably includes copper and at least one selected from the group consisting of nickel, tungsten, and molybdenum.
Although most of the metal adhering to the activated carbon is considered to be contained as a compound (oxide, inorganic acid salt, organic acid salt, etc.) containing a metal element, it may be contained as a simple metal. .

  The amount of metal attached to the activated carbon is preferably 1.0% by mass to 20.0% by mass, and 2.0% by mass to 15.0% by mass with respect to the total mass of the activated carbon. Is more preferable, and it is still more preferable that it is 2.0 mass%-8.0 mass% or less.

  When the metal attached to the activated carbon contains copper and other metals, the amount of copper attached is preferably 20% by mass to 80% by mass with respect to the total mass of the metal attached to the activated carbon, More preferably, it is 30 mass%-80 mass% or less, It is further more preferable that it is 40 mass%-80 mass% or less, It is especially preferable that it is 40 mass%-65 mass% or less.

  In the present specification, the amount of metal attached to the activated carbon is a value measured by ICP (Inductively Coupled Plasma) emission spectroscopy. 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.

An example of a method for producing activated carbon with a metal attached will be described. The activated carbon to which the metal is attached can be produced, for example, by the following method. However, the manufacturing method of the activated carbon to which the metal is attached 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 after firing is fired to form a metal oxide or the like on the activated carbon.
By the above method, activated carbon to which a metal is impregnated can be produced.

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.

When the fuel cell system includes at least an adsorbing part as a deodorizing part, the odorant used for the odor of hydrogen gas is other than a sulfur compound, and is adsorbed by the adsorbent and capable of deodorizing hydrogen gas. If it does not specifically limit. Specifically, as the odorant, 1-pentene, cis-2-pentene, trans-2-pentene, 2-methyl 1-butene, 3-methyl 1-butene, 2-methyl 2-butene, allene, Methyl allene, ethyl allene, 1,3-pentadiene, 2-methyl 1,3-butadiene, 2,3-dimethyl 1,3-butadiene, 1,4-pentadiene, 1,5-hexadiene, 1,6-heptadiene, 1,3,5-hexatriene, 1-butyne, 2-butyne, styrene, vinylacetylene, heptene, octene, nonene, decene, propylene, 1-butene, isobutene, trans-2-butene, cis-2-butene, 1,5-hexadiene 3-yne, diisobutylene, 1-hexene, isoprene, 1,3-butadiene, 1,2-butadiene, cyclopente , Cyclopentadiene (dicyclopentanediene), 1,3-cyclohexadiene, 1,3-cycloheptadiene, 1,5-cyclooctadiene, 1,5,9-cyclododecatriene, 4-vinylcyclohexene-1, 1-vinylcyclohexene-1,5-ethylidene-2-norbornene, 5-vinyl-2-norbornene, bicyclopentadiene, cyclohexene, 1-methylpyrrole, pyrazine, 2-methylpyrazine, 2-methyl-3-isobutylpyrazine, 2 , 3-dimethylpyrazine, 2,5-dimethylpyrazine, 2,6-dimethylpyrazine, 2,3,5-trimethylpyrazine, 2-ethylpyrazine, 2-propylpyrazine, 2-vinylpyrazine, 2-allylpyrazine, 2 -Picoline, α. p-dimethyl-styrene, cumene, 2,5-diethylpyrazine, limonene, mesitylene, 2-methylnaphthalene, 3-methylindole (skatole), myrcene, α-pinene, 1-octen-3-one, 2,3- Butanedione, pentane-2,3-dione, hexane-2,5-dione, heptane-2,5-dione, ethylidene diethyl ether, isopropanol, n-butanol, isobutanol, amyl alcohol, propargyl alcohol, β, γ- Hexenol (cis-hexen-1-ol), formaldehyde, acetaldehyde, propionaldehyde, hexanal (caproaldehyde), cuminaldehyde, acetone, 2-octanone, 3-octanone, diacetyl (2,3-butanedione), acetophenone, methylphospho Mate, methyl acetate, methyl propionate, methyl phenyl acetate, ethyl formate, ethyl acetate, isopropyl formate, isoamyl acetate, n-amyl acetate, phenyl ethyl formate, 2-isopentenyl acetate, ethyl propionate, butyl Acetate, isobutyl acetate, amyl propionate, ethyl caproate, amyl butyrate, ethyl caprylate, ethyl caprate, hexyl butyrate, ethyl cinnamate, benzyl acetate, ethyl crotonate, ethyl 3,3-dimethyl acrylate, Ethyl-4-methyl-4-pentenoate, ethyl-4-methyl-3-pentenoate, ethyl hept-3-enoate, ethyl pyruvate, propyl crotonate, methyl Acrylate, butyl acrylate, allyl acrylate, methyl methacrylate, menthyl acetate, bornyl acetate, β-phenyl ethyl acetate, allyl caproate, ethyl methyl phenyl glycidate, p-cresyl acetate, acetol acetate, ethyl 9-decenoate 2,3-octanedione, methyl-3-acetoxy-butanoate, propionoin, 2-methyl-2-pentenal, acetoin acetate, methyl 3-hydroxy-butyrate, 2-methyl-1-hepten-3-ol, 8-nonene 2-one, acetoin, 3-methyl-3-butenyl acetate, tetrahydrocitral, allyl alcohol, butanal (butyraldehyde), 2,3-butanedione (diacetyl), isobutyl cello Rub, isobutyraldehyde, carbitol acetate, 2-decenal, decanal, diisobutyl carbinol, dodecanal (lauryl aldehyde), ethyl acrylate, ethyl butyrate, ethyl valerate, ethyl vinyl ketone, ethyl 2-methylbutyrate, heptanal, 1 -Heptanol, 2-heptanone, 2-heptenal, 2-hexenol, mesityl oxide, 2-methylbutanal-1, 3-methylbutanal-1, 2-methylbutanol, methyl isoamyl ketone (5-methyl-2- Hexanone), 2-methyl-1-pentanol, 2-methylbutyl acetate, 2-methylpropanal (isobutyraldehyde), 2-nonanal, n-nonanal (pelargonaldehyde), 2-octenal, octa (N-caprylaldehyde), octyl acetate, 1-penten-3-one (ethyl vinyl ketone), isopentanal, pentanal (valeraldehyde), 2,4-pentanedione (acetylacetone), isopentyl acetate (isoamyl) Acetate), pentyl acetate (n-amyl acetate), propanal (propionaldehyde), propanoic acid, propylbutyrate, undecanal, butyroin, tetrahydrofuran, 2-methyltetrahydrofuran, cyclohexene oxide, m-cresol, N- (2 ' -Furfuryl) pyrrole, 2-pyrrolealdehyde, 5-methyl-2-pyrrolealdehyde, N-ethylpyrrolealdehyde, 2-acetyl-N-methylpyrrole, diketene, 5-acetyl-2-methyl Luxazole, 2-acetylfuran, 2-methylfuran, furfural, furfurylacetone, 5-methyl-2-furfural, dihydrofuranone, cyclopentanone, phenyl n-butyrate, 2-phenyl-2-butenal, difurfuryl ether Chrysanthenone, 2-butene-4-olide, 2-methoxyphenol (Gaiacol), 2-methoxy-3-ethylpyrazine, 2-methoxy-3-isobutylpyrazine, 2-methoxy-3-isobutylpyridine, 2-methoxy -3-Isopropylpyrazine, 2-methoxy-3-propylpyrazine, anisole, benzaldehyde, 1,8-cineol, cyclopentyl acetate, 2-ethoxy-3-ethylpyrazine, 2-hydroxy-3-methoxybenzaldehyde (o-vanillin) Phenyl ether and the like. Of these, cyclohexene is preferred.
In addition, as an odorant, 1 type may be used independently and 2 or more types may be used together.

  The bromide-free part is not particularly limited as long as it has a structure in which an odorant is reacted with hydrogen gas to form an odorless component (including one having a odor reduced from that of the original odorant). The odorant is not limited as long as it becomes an odorless component by reaction with hydrogen gas, for example, a hydrogen addition reaction, specifically, an unsaturated hydrocarbon having a double bond in the odorant described above. Are preferred, and cyclohexene is more preferred.

  Also, in the non-bromide part, the odorant is made an odorless component using part of the hydrogen gas used as fuel for the fuel cell, so there is no need for piping, valves, etc. for supplying hydrogen gas to the non-bromide part separately. Yes, the configuration of the fuel cell system can be simplified.

  As the non-bromide part, a catalyst for hydrogenation reaction in an odorant may be provided, or a heating means may be provided.

  As a catalyst, what is used for the catalytic hydrogenation reaction of the unsaturated hydrocarbon which has a double bond can be used suitably, for example, platinum, palladium, rhodium, ruthenium, nickel etc. are mentioned.

  The non-bromide part may be provided with a heating means from the viewpoint of promoting the hydrogenation reaction. The heating means may be a heat source such as a heater, a configuration in which heat generated in the fuel cell (for example, hot water generated in a polymer electrolyte fuel cell or the like) is supplied, in a combustion section described later The structure etc. which the heat | fever produced by combustion of the odorless component may be supplied may be sufficient.

  The concentration of the odorant for odorizing hydrogen gas (concentration of the odorant before being supplied to the deodorizing unit and the fuel cell) is particularly 0.1 ppm to 5000 ppm as the concentration of cyclohexene. Preferably, it is 1 ppm to 1000 ppm, more preferably 10 ppm to 500 ppm, and particularly preferably 50 ppm to 300 ppm.

  Further, it is not necessary to adsorb all odorants or to make them odorless components in the deodorizing section, and it is sufficient that the concentration of the odorant is equal to or lower than the detected concentration when released into the atmosphere.

From the viewpoint of allowing the hydrogen addition reaction between the hydrogen gas and the odorant to proceed at a lower temperature, the non-bromide portion may have a configuration in which a catalyst is disposed between a pair of electrodes and a voltage is applied between the electrodes. . Due to the electric field generated between the electrodes, the catalytic activity is improved, and the reaction can be performed at a low temperature and the reaction efficiency can be improved.
Furthermore, from the viewpoint of suppressing the generation of by-products and the required electrical energy, the voltage applied between the electrodes is preferably less than the lowest voltage (discharge generation voltage) that causes discharge between the electrodes. Moreover, it is preferable to select the catalyst used in the hydrogen addition reaction between the hydrogen gas and the odorant so that the discharge is not easily generated when a voltage is applied between the electrodes.

  Moreover, you may use the electric power generated with the fuel cell system of this embodiment as a power supply which applies a voltage between the power supply of the above-mentioned heating means, and an electrode.

(Decompression section)
The fuel cell system of this embodiment includes a decompression unit that is disposed upstream of the fuel cell and decompresses hydrogen gas. For example, a configuration in which the hydrogen gas is decompressed to a pressure suitable for the specifications of the fuel cell or the like by the decompression unit is preferable, and a configuration in which the supply pressure of the hydrogen gas is decompressed from about 0.1 MPa as a medium pressure to about 0.02 MPa as a low pressure. preferable. The decompression unit is not particularly limited as long as it has a configuration for reducing the supply pressure of the supplied hydrogen gas.

  The fuel cell system preferably includes a deodorization unit upstream of the decompression unit. That is, before depressurizing the hydrogen gas, it is preferable to adsorb an odorant that odorizes the hydrogen gas or to react the odorant with the hydrogen gas to make an odorless component. The higher the partial pressure of the odorant, the higher the adsorption performance of the adsorbent, and the higher the pressure, the more the reaction between the odorant and hydrogen (for example, the hydrogenation reaction of the odorant) proceeds. This tends to increase the efficiency of producing odorless components. Furthermore, compared to the case where the deodorizing unit is arranged downstream of the decompression unit, the loading amount of the adsorbent is reduced, or the loading amount of the catalyst that may be necessary when the odorant is reacted with hydrogen gas is reduced. This can reduce the cost of the fuel cell system. Moreover, it is preferable that a decompression part is the structure which decompresses hydrogen gas rather than the pressure of the hydrogen gas supplied to a deodorizing part.

  Moreover, when making an odorant react with hydrogen gas and making it an odorless component, you may arrange | position the non-bromide part as a deodorizing part upstream of a fuel cell. Thereby, hydrogen gas is supplied to the fuel cell in the form of a mixed gas with an odorless component rather than a mixed gas with an odorant. Usually, an odorless component (for example, a saturated hydrocarbon obtained by adding hydrogen to an unsaturated hydrocarbon, preferably cyclohexene) is an odorant (for example, an unsaturated hydrocarbon having a double bond, preferably cyclohexene). It is more chemically stable and less likely to adhere to the electrode catalyst of the fuel cell. Therefore, when an odorless component is supplied to a fuel cell, it is thought that the output fall of a fuel cell is suppressed rather than the case where an odorant is supplied to a fuel cell.

  In the fuel cell system, when the deodorization unit is provided upstream of the decompression unit, it is preferable to arrange a hydrogen detector or the like in the decompression unit so that hydrogen leakage can be detected.

  The fuel cell system may include a deodorizing unit downstream of the fuel cell. For example, when an odorant other than a sulfur compound such as TBM (t-butyl mercaptan) or DMS (dimethylsulfide) is used, particularly when a hydrocarbon odorant such as cyclohexene is used, the fuel by the odorant Poisoning of the battery electrode catalyst is suppressed, and even if a deodorizing part is provided downstream of the fuel cell, adverse effects such as a decrease in the output of the fuel cell tend to be suppressed.

  In a fuel cell system, when a non-bromide part, which is a deodorizing part, is arranged downstream of the fuel cell, the fuel cell is operated so that unreacted hydrogen gas is supplied to the deodorizing part. Is preferred. That is, the fuel cell is operated and the consumption of hydrogen gas in the fuel cell is adjusted so that the anode off-gas discharged from the fuel cell contains the hydrogen gas in an amount necessary for reacting with the odorant. Is preferred.

  When the deodorizing part is arranged downstream of the fuel cell, when a polymer electrolyte fuel cell (PEFC), phosphoric acid fuel cell (PAFC), etc. is used as the fuel cell, it is supplied to the anode and used for power generation. Since the generated hydrogen moves in the electrolyte as protons and reacts with oxygen on the cathode side, the concentration of the odorant in the anode off-gas is increased by the amount of hydrogen gas used for power generation. Therefore, when the deodorizing part is disposed downstream of the fuel cell, the adsorption of the odorant in the adsorption part and the reaction between the odorant and hydrogen gas in the non-bromide part tend to occur more efficiently. For this reason, it is possible to reduce the mounting amount of the adsorbent or to reduce the mounting amount of the catalyst that may be required when the odorant is reacted with hydrogen gas, and it is considered possible to reduce the cost.

  Moreover, when the deodorization part is provided as a deodorization part, you may further provide the combustion part which burns an odorless component downstream from a non-bromide part and a fuel cell. Thereby, the odorless component produced | generated in the non-bromide part is provided to a combustion reaction with unreacted hydrogen gas. The heat generated by the combustion reaction may be supplied to the non-brominated portion. At this time, a configuration may be adopted in which a gas containing unreacted hydrogen and odorless components as anode off-gas is supplied to the combustion section, and a gas containing unreacted oxygen as cathode off-gas is supplied to the combustion section.

  In the fuel cell system, the deodorizing unit may be arranged upstream and downstream of the fuel cell. At this time, a switching unit capable of switching the gas flow path so that the gas flowing in the system is supplied to at least one of the deodorizing unit arranged upstream of the fuel cell and the deodorizing unit arranged downstream of the fuel cell. Is preferably further provided. As a result, the gas flowing through the system is supplied to at least one of the deodorizing units. For example, even when the maintenance of one of the deodorizing units is required, it is necessary to stop the operation of the fuel cell system. In this way, the fuel cell system can be operated continuously.

  When the deodorizing unit is arranged upstream and downstream of the fuel cell, the anode gas is supplied in the order of the upstream deodorizing unit (first deodorizing unit), the fuel cell, and the downstream deodorizing unit (second deodorizing unit). In this way, a gas flow path may be provided. At this time, a first branch path that branches from the flow path upstream of the first deodorization unit and merges with the flow path upstream of the fuel cell may be disposed, and downstream of the fuel cell and of the second deodorization unit. You may arrange | position the 2nd branch path which branches a distribution path upstream and merges with a distribution path downstream of a 2nd deodorizing part. The switching unit may appropriately switch which of the first deodorizing unit and the first branch path is supplied with gas and which of the second deodorizing unit and the second branch path is supplied with gas.

  Furthermore, the fuel cell system may further include a control unit that controls switching of the switching unit according to the output (output voltage) of the fuel cell. For example, when the output of the fuel cell is greater than a predetermined value, the control unit is configured to perform a first deodorization in which hydrogen gas odorized by an odorant that is a gas flowing through the system is disposed upstream of the fuel cell. The switching of the switching unit is controlled so that the gas containing the odorant (anode offgas) discharged from the fuel cell and supplied to the second deodorizing unit is controlled, and the gas flow path is switched. Also good. In addition, the control unit is configured such that when the output of the fuel cell becomes equal to or less than a predetermined value, the hydrogen gas odorized by the odorant that is a gas flowing through the system is disposed upstream of the fuel cell. Even if the gas distribution path is switched by controlling the switching of the switching unit so that the gas (anode off gas) supplied to the deodorizing unit and containing the odorant discharged from the fuel cell is not supplied to the second deodorizing unit Good.

  Hereinafter, specific configurations 1 to 3 of the fuel cell system according to the present embodiment will be described with reference to FIGS. 1 to 3. The present invention is not limited to these specific configurations.

<Specific configuration of fuel cell system 1>
As shown in FIG. 1, the fuel cell system 10 includes a deodorization unit 1, a decompression unit 2, and a fuel cell 3. Further, in the fuel cell system 10, the hydrogen gas odorized by the odorant is supplied to the deodorizing unit 1 through the distribution channel 4, and the hydrogen gas deodorized through the distribution channel 4 is supplied to the decompression unit 2 and the fuel cell 3 in this order. It becomes the composition which is done.

  The hydrogen gas odorized by the odorant is supplied to the deodorization unit 1 through the distribution channel 4, and the odorant is adsorbed by the adsorbent in the deodorization unit 1 or reacts with the hydrogen gas and is odorless. Become an ingredient. The deodorized hydrogen gas is decompressed by the decompression unit 2 through the flow path 4, and then supplied to the fuel cell 3 as an anode gas and electrochemically with oxygen gas supplied to the fuel cell 3 as a cathode gas. Electricity is generated by a simple reaction. The gas (anode off gas) discharged from the fuel cell 3 is released into the atmosphere. Since the decompression unit 2 is located downstream of the deodorization unit 1, the adsorption performance of the adsorbent tends to increase due to the higher partial pressure of the odorant, and the higher pressure increases the attachment. The reaction between the odorant and hydrogen (for example, the hydrogenation reaction of the odorant) tends to proceed and the generation efficiency of odorless components tends to increase.

<Specific configuration 2 of the fuel cell system>
As shown in FIG. 2, the fuel cell system 20 includes a deodorizing unit 1, a decompression unit 2, a fuel cell 3, and a combustion unit 5 as the deodorizing unit 1. Further, in the fuel cell system 20, the hydrogen gas odorized by the odorant is supplied to the non-brominated portion through the distribution path 4, and the mixed gas of the odorless component and hydrogen is supplied to the decompression section 2 and the fuel cell 3 through the distribution path 4. The gas (anode offgas) discharged from the fuel cell 3 is supplied to the combustion unit 5 in this order. The heat generated by the combustion reaction of the odorless component in the combustion section 5 is supplied to the non-bromide section, the hydrogen addition reaction in the non-bromide section is promoted, and the combustion off-gas discharged from the combustion section 5 is released into the atmosphere. Released. Furthermore, since the odorless component is chemically more stable than the odorant and hardly adheres to the electrode catalyst of the fuel cell, when the odorless component is supplied to the fuel cell, the odorant is supplied to the fuel cell. It is considered that the output decrease of the fuel cell is suppressed more than in the case of

  Instead of disposing the combustion unit 5, heat generated in the fuel cell 3 (for example, hot water generated in a solid polymer fuel cell or the like) is supplied to a non-bromide unit as the deodorizing unit 1. Also good. Although not shown in FIG. 2, the cathode off gas containing unreacted oxygen discharged from the fuel cell 3 may be supplied to the combustion section, and the gas containing oxygen such as cathode gas is burned. The structure supplied to a part may be sufficient.

<Specific configuration 3 of the fuel cell system>
As shown in FIG. 3, the fuel cell system 30 includes a first deodorization unit 11, a decompression unit 2, a fuel cell 3, and a second deodorization unit 12. The fuel cell system 30 further includes a control unit 8 that controls the opening / closing of the on-off valves 21 to 28 and the on-off valves 21 to 28 as switching units. Whether to supply gas to the first branch path 6 branched from the path 4 and whether to supply gas to the second branch path branched from the distribution path 4 can be switched.

  Hereinafter, an example of opening / closing control of the opening / closing valves 21 to 28 by the control unit 8 will be described. First, the control unit 8 controls to open the on-off valves 21, 23, 26, and 28 and close the on-off valves 22, 24, 25, and 27, and distributes hydrogen gas odorized by the odorant to the flow path 4. To distribute. Thereby, the hydrogen gas odorized by the odorant is supplied to the first deodorizing unit 11, and the gas (anode offgas) discharged from the fuel cell 3 is not supplied to the second deodorizing unit 12 and is supplied to the first deodorizing unit 11. A two-branch route 7 is distributed.

  And when the maintenance etc. of the 1st deodorizing part 11 are needed, it controls by the control part 8 so that the on-off valves 22, 24, 25, and 27 are opened and the on-off valves 21, 23, 26, and 28 are closed. Thereby, the hydrogen gas odorized by the odorant flows through the first branch path 6 without being supplied to the first deodorizing unit 11, and the gas (anode offgas) discharged from the fuel cell 3 is the second. It is supplied to the deodorizing unit 12.

Next, when maintenance or the like of the second deodorizing unit 12 becomes necessary, the control unit 8 controls to open the on-off valves 21, 23, 26, and 28 and close the on-off valves 22, 24, 25, and 27. To do. Thereby, the hydrogen gas odorized by the odorant is supplied to the first deodorizing unit 11, and the gas (anode offgas) discharged from the fuel cell 3 is not supplied to the second deodorizing unit 12 and is supplied to the first deodorizing unit 11. A two-branch route 7 is distributed. Hereinafter, these operations may be repeated.
As described above, even when the first deodorizing unit 11 or the second deodorizing unit 12 needs to be maintained, it is not necessary to stop the operation of the fuel cell system, and the fuel cell system can be continuously operated.

  Further, when the hydrogen gas odorized by the odorant is not supplied to the first deodorizing unit 11 and the gas discharged from the fuel cell 3 is supplied to the second deodorizing unit 12, the odor is added to the fuel cell 3. Hydrogen gas odorized to the agent is supplied, and the output of the fuel cell 3 may gradually decrease due to the influence of the odorant adhering to the electrode catalyst of the fuel cell 3. In view of this, the on / off valves 21 to 28 may be controlled to open / close according to the output of the fuel cell 3.

  For example, when the output of the fuel cell 3 falls below a predetermined value (first threshold), the on-off valves 21, 23, 26 and 28 are opened, and the on-off valves 22, 24, 25 and 27 are closed. Control by unit 8. As a result, the hydrogen gas from which the odorant has been removed, or the mixed gas of the odorless component and hydrogen in which the odorant is converted to the odorless component is supplied to the fuel cell 3. The odorant or the like attached to the electrode catalyst is removed, and the output of the fuel cell 3 is restored.

  Further, when the output of the fuel cell 3 recovers and the output of the fuel cell becomes equal to or higher than a predetermined value (second threshold), the on-off valves 22, 24, 25, and 27 are opened, and the on-off valves 22, 24, You may control by the control part 8 so that 25 and 27 may be closed.

  The opening / closing control of the opening / closing valves 21 to 28 by the control unit 8 is not limited to the above-described configuration. For example, the on-off valves 21, 23, 25 and 27 are normally opened and the on-off valves 22, 24, 26 and 28 are closed, and the first deodorization unit 11 and the second deodorization are performed as necessary for maintenance. The on-off valves 21 to 28 may be appropriately controlled so that the gas is not supplied to the part 12.

  Hereinafter, the experimental result about the adsorption effect of the odorant by the adsorbent when hydrogen gas and city gas are used as the base gas to be odorized will be shown. The present invention is not limited to the following examples as long as the gist thereof is not exceeded.

(Example 1 and Reference Example 1)
As a base gas to be odorized, hydrogen gas was used in Example 1, and city gas (desulfurized city gas) was used in Reference Example 1. Cyclohexene was used as the odorant, and the base gas was odorized so that the concentrations shown in Table 1 were obtained.
The components of city gas used in the reference examples are methane 89.6%, ethane 5.62%, propane 3.43% and butane 1.35%.

As the adsorbent, as shown in Table 2, activated carbon to which Cu and Ni were impregnated (Cu addition amount 3.3 mass% and Ni addition amount 3. 1% by mass), activated carbon impregnated with Br (Br impregnated coal, Osaka Gas Chemical Co., Ltd., trade name: granular white birch SRCX) and silver supported zeolite (Ag-Y zeolite, JGC Catalysts & Chemicals Co., Ltd., trade name: FKS- A, supported amount of silver: 14% by mass with respect to the mass of zeolite).
In addition, the amount of copper and nickel deposited in CuNi-added coal was measured by ICP emission spectroscopic analysis using Optima 8000 (product name) manufactured by Perkin-Elmer.

  Each condition when the gas odorized by the odorant is circulated through the test tube in which the adsorbent is arranged is as shown in Table 1.

<Cyclohexene adsorption test>
The amount of cyclohexene adsorbed on the adsorbent was measured as described below.
First, the desulfurized city gas and cyclohexene used in Reference Example 1 are mixed after the flow rate is adjusted by an MFC (mass flow controller). The mixed gas was passed through an adsorbent that adsorbs and removes cyclohexene, and the gas after passing through the adsorbent was analyzed by GC (gas chromatograph). When cyclohexene is not detected by GC, it can be seen that cyclohexene is removed by the adsorbent. When cyclohexene is detected by GC, it is determined that cyclohexene cannot be removed by the adsorbent. The amount of adsorbed cyclohexene was calculated and used as the amount of adsorbed cyclohexene.
The results are shown in Table 2.

As shown in Example 1 of Table 2, when hydrogen gas is used as the base gas, it is adsorbed by using activated carbon (CuNi-added carbon or Br-added carbon) than when zeolite (Ag-Y zeolite) is used. It was shown that the amount of cyclohexene adsorbed by the agent was excellent.
On the other hand, as shown in Reference Example 1 of Table 2, when city gas is used as the base gas, by using activated carbon (CuNi-added coal or Br-added coal), it is more than when zeolite (Ag-Y zeolite) is used. It was also shown that the amount of cyclohexene adsorbed on the adsorbent decreased.
Therefore, the type of preferred adsorbent varies depending on the base gas, and when hydrogen gas is used as the base gas, activated carbon, preferably activated carbon impregnated with metal is used as the adsorbent, resulting in excellent cyclohexene adsorption effect. It has been shown.

  DESCRIPTION OF SYMBOLS 1 ... Deodorizing part, 2 ... Decompression part, 3 ... Fuel cell, 4 ... Distribution path, 5 ... Combustion part, 6 ... 1st branch path, 7 ... 2nd Branch path, 10, 20, 30 ... fuel cell system, 11 ... first deodorization unit, 12 ... second deodorization unit, 21-28 ... open / close valve (switching unit)

Claims (8)

A fuel cell for generating electricity by distributing hydrogen gas odorized by an odorant other than a sulfur compound;
An adsorbing portion that is disposed at least one of the upstream and downstream sides of the fuel cell and includes an adsorbent that adsorbs the odorant, and reacts with the hydrogen gas an odorant that can be not brominated by reaction with the hydrogen gas. A deodorizing part which is at least one of a non-bromide part to be an odorless component,
A decompression unit disposed upstream of the fuel cell and decompressing the hydrogen gas;
A fuel cell system comprising:   The fuel cell system according to claim 1, wherein the deodorizing unit is disposed upstream of the decompression unit.   The fuel cell system according to claim 1, wherein the deodorizing unit is disposed downstream of the fuel cell. At least the non-bromide part as the deodorizing part disposed downstream of the fuel cell,
The fuel cell system according to claim 3, wherein the fuel cell is operated so that unreacted hydrogen gas in the fuel cell is supplied to the deodorization unit disposed downstream of the fuel cell. At least the adsorbing part as the deodorizing part,
The fuel cell system according to any one of claims 1 to 4, wherein the adsorbent includes at least one of activated carbon and activated carbon to which a metal is attached.   The fuel cell system according to any one of claims 1 to 5, wherein the adsorbent includes activated carbon to which a metal is attached. The deodorizing unit is disposed upstream and downstream of the fuel cell,
Switching capable of switching the gas flow path so that the gas flowing through the system is supplied to at least one of the deodorizing unit disposed upstream of the fuel cell and the deodorizing unit disposed downstream of the fuel cell. The fuel cell system according to any one of claims 1 to 6, further comprising a unit. A control unit that controls switching of the switching unit according to the output of the fuel cell;
The control unit controls the switching of the switching unit when the output of the fuel cell becomes a predetermined value or less, so that the hydrogen odorized by the odorant that is a gas circulating in the system The fuel cell system according to claim 7, wherein a gas flow path is switched so that gas is supplied to the deodorizing unit disposed upstream of the fuel cell.