JP4953584B2 - Fuel cell system - Google Patents

Description

  The present invention relates to a fuel cell system using liquefied petroleum gas having a composition suitable for a fuel cell system as a fuel.

  In recent years, due to the growing sense of crisis about the global environment in the future, development of an energy supply system that is friendly to the earth has been demanded. From the viewpoint of high energy efficiency and clean exhaust gas, fuel such as fuel cells and hydrogen engines can be used as fuel. The system is in the limelight. In particular, as a method of supplying hydrogen to the fuel cell, in addition to a method of directly supplying hydrogen in the form of compression or liquefaction, a supply method by reforming oxygen-containing fuel such as methanol and hydrocarbon fuel such as naphtha. Is known (see, for example, Non-Patent Document 1). Among these, the method of supplying hydrogen directly has an advantage that it can be used as a fuel as it is, but it has a problem in storability and mountability when used in a vehicle or the like because it is a gas at room temperature. On the other hand, the production of hydrogen by reforming hydrocarbon fuels such as liquefied petroleum gas has attracted attention due to the fact that the existing fuel supply infrastructure can be used and the total energy efficiency is high.

In Patent Document 1, as a fuel for a fuel cell system, isoparaffin in a saturated component having a saturated content of 60 mol% or more, an olefin content of 40 mol% or less, a butadiene content of 0.5 mol%, and a carbon number of 4 or more is 0. A fuel for a fuel cell system comprising a hydrocarbon compound that is 1 mol% or more and is a gas at normal temperature is disclosed.
The properties of liquefied petroleum gas used as household fuel are usually in the liquid state, and the content of hydrocarbon compounds with 3 carbon atoms is 80% by volume or more, and the content of hydrocarbon compounds with 2 carbon atoms is 5% by volume. Hereinafter, the content of the hydrocarbon compound having 4 carbon atoms is 25% by volume or less, and methanol is added to prevent moisture from condensing in the winter and adversely affecting the gas supply device. The amount added is approximately 300 ppm by mass or more or 450 ppm by mass or more depending on the supply area except Okinawa. Further, the liquefied petroleum gas fuel usually contains about several ppm to several tens of ppm of a sulfur compound. Since this sulfur compound is a catalyst poison for a catalyst charged in a reformer for the purpose of producing hydrogen for fuel cells or a catalyst used in fuel cells, it must be removed and constitutes a fuel cell system. Generally, a desulfurizer filled with a desulfurizing agent is installed upstream of the reformer to remove sulfur compounds in the fuel gas, but it is added to prevent condensation. The effect of methanol on the performance of desulfurizing agents has not been studied, and no study has been made on the fuel composition suitable for liquefied petroleum gas fuel cells, focusing on the performance of desulfurizing agents.

Masaki Ikematsu, “Engine Technology”, Sankai-do Co., Ltd., January 2001, Vol. 3, No. 1, p. 35 International Publication No. 02/000813 Pamphlet

  The present invention has been made in view of such a situation, and even when a minimum amount of a desulfurizing agent is used, the desulfurizing agent functions efficiently, the desulfurizing effect is improved, and hydrogen production is arranged downstream from the desulfurizer. An object of the present invention is to provide a fuel cell system capable of preventing damage to a reforming catalyst in a reformer for industrial use and enabling stable operation of the reformer and stable power generation.

  As a result of intensive research to achieve the above object, the present inventors have used liquefied petroleum gas having a specific composition as a fuel for fuel cells, thereby improving the desulfurization effect even with the use of a minimum desulfurization agent. Thus, it is possible to prevent damage to the reforming catalyst in the reformer for hydrogen production arranged downstream from the desulfurizer, and to enable stable operation of the reformer and stable power generation. The present invention was completed based on this finding.

That is, the present invention
(1) In a fuel cell system using liquefied petroleum gas to which methanol is added to prevent condensation as a fuel , the content of a hydrocarbon compound having 2 carbon atoms is 5% by volume or less, and the content of a hydrocarbon compound having 4 carbon atoms is A fuel cell system characterized in that a liquefied petroleum gas comprising a hydrocarbon compound having a volume of 25% by volume or less and a methanol content of 30 ppm by mass or less and a residue of 3 carbon atoms is subjected to desulfurization treatment.
(2) The fuel cell system according to (1), wherein the methanol content is 15 mass ppm or less.
(3) The fuel cell system according to (1), wherein the gaseous liquefied petroleum gas is used after being desulfurized with a desulfurizing agent containing zeolite.
(4) The fuel cell system according to (3), wherein the zeolite has a beta (BEA) and / or faujasite (FAU) structure.
(5) A group in which a desulfurizing agent containing zeolite is composed of an Ag component, a Cu component, a Ni component, a Zn component, a Mn component, an Fe component, a Co component, an alkali metal component, an alkaline earth metal component, and a rare earth metal component together with zeolite. The fuel cell system according to (3) or (4), comprising at least one metal component selected from the group consisting of:
(6) The fuel cell system according to (1), wherein the gaseous liquefied petroleum gas is used after being desulfurized with a desulfurization agent composed of at least one selected from a metal element, a metal oxide, and a metal component-supported oxide. .
(7) A desulfurization agent comprising at least one selected from metal elements, metal oxides and metal component-supported oxides is an Ag component, a Cu component, a Ni component, a Zn component, a Mn component, an Fe component, a Co component, Si The fuel cell system according to (6), comprising at least one metal component selected from the group consisting of a component, an Al component, an alkali metal component, an alkaline earth metal component, and a rare earth metal component;
It is.

  According to the present invention, since liquefied petroleum gas having a specific composition is used as a fuel for hydrogen production for a fuel cell, the desulfurization agent in the desulfurizer functions efficiently even with the use of a minimum desulfurization agent, and the desulfurization effect is obtained. Improved fuel cell system that can prevent damage to the reforming catalyst in the reformer for hydrogen production that is disposed downstream from the desulfurizer and enables stable reformer operation and stable power generation Can be provided.

Hereinafter, the present invention will be described in more detail.
In the present invention, the liquefied petroleum gas used as fuel has a content of hydrocarbon compound having 2 carbon atoms of 5% by volume or less, a content of hydrocarbon compound of 4 carbon atoms of 25% by volume or less, and a methanol content of 30%. The content is not more than ppm by mass, preferably not more than 15 ppm by mass, and the balance is composed of a hydrocarbon compound having 3 carbon atoms.

The hydrocarbon compound having 3 carbon atoms is a paraffin and / or olefin having 3 carbon atoms, and the hydrocarbon compound having 2 carbon atoms is also a paraffin and / or olefin having 2 carbon atoms. The hydrocarbon compound having 4 carbon atoms is at least one hydrocarbon compound selected from paraffins, olefins and diolefins having 4 carbon atoms.
When the content of the hydrocarbon compound having 3 carbon atoms in the gas supplied to the hydrogen production system is out of the above composition range, or when the content of the hydrocarbon compound having 4 carbon atoms exceeds 25% by volume, the fuel gas Since the supply amount is substantially reduced, a predetermined amount of power cannot be obtained. Further, when steam is added during reforming, the steam / carbon ratio may fluctuate and the operation of the reformer may become unstable.
The composition for each carbon number is measured by the analysis method described in JIS K 2240 “Liquefied petroleum gas 5.9 composition analysis method”.

The content of methanol is 30 mass ppm or less, preferably 15 mass ppm or less. If it exceeds 30 ppm by mass, the effect on the desulfurizing agent is large, and as a result, the amount of the desulfurizing agent to be used increases and the fuel cell system itself becomes large. Disadvantageous.
Here, the methanol content is measured according to Japan LP Gas Association Standard (JLPG-S-06T).

The sulfur concentration in the liquefied petroleum gas of the present invention is 10 mass ppm or less, preferably 5 mass ppm or less, more preferably 3 mass ppm or less. If it exceeds 10 ppm by mass, the amount of desulfurizing agent to be used increases, and the size of the desulfurizer becomes excessively large, which is not only economically disadvantageous but also limited by the size of the fuel cell system itself.
Here, the sulfur concentration is a concentration measured by JIS K 2240 “Liquefied petroleum gas 5.5 or 5.6 sulfur content test method”.

The vapor pressure of the liquefied petroleum gas of the present invention is not particularly limited, but the vapor pressure at 40 ° C. is preferably 1.56 MPa · G or less, and more preferably 1.53 MPa · G or less. The vapor pressure at 40 ° C. is measured by the method described in JIS K 2240 “Liquefied petroleum gas 5.4 vapor pressure test method”.
The density of the liquefied petroleum gas is not particularly limited, but is preferably 0.620 g / cm ³ or less at 15 ° C., and more preferably 0.500 to 0.620 g / cm ³ . The density at 15 ° C. is measured by the method described in JIS K 2240 “Liquid petroleum gas 5.7 or 5.8 density test method”.
Moreover, although there is no restriction | limiting about the copper plate corrosivity of the liquefied petroleum gas of this invention, The copper plate corrosion degree of 1 hour at 40 degreeC is preferable.
The copper plate corrosion degree at 40 ° C. for 1 hour is measured by the method described in “Liquid petroleum gas 5.10 copper plate corrosion test method” of JIS K 2240.

  The type of the fuel cell using the liquefied petroleum gas of the present invention is not particularly limited, and examples thereof include a solid oxide fuel cell (SOFC), a solid polymer fuel cell (PEFC), and a phosphoric acid fuel cell (PAFC). It can be applied to any fuel cell such as a molten carbonate fuel cell (MCFC).

  There is no restriction | limiting in particular about the manufacturing method of liquefied petroleum gas. For example, there are a method in which gas components produced as a by-product from oil fields and natural gas fields are refined and compressed, and a method in which crude oil is purified. In the process of refining crude oil, liquefied petroleum gas components obtained with crude oil atmospheric distillation equipment and liquefied petroleum gas components obtained with naphtha catalytic reforming equipment and catalytic cracking equipment are separated by distillation, then sulfur components are removed and further distilled. By separating, liquefied petroleum gas at the primary base of desired purity can be obtained. The removal of the sulfur component is performed by a method appropriately selected from hydrodesulfurization, soda cleaning, amine cleaning, and Marlox.

  Usually, in liquefied petroleum gas used as fuel for fuel cells, a small amount of sulfur component not removed in the crude oil refining process and sulfur component added as an odorant, for example, mercaptans such as methyl mercaptan, carbonyl sulfide , Sulfur compounds such as hydrogen sulfide, sulfides and disulfides are included. When hydrogen for fuel cells is produced by reforming liquefied petroleum gas, it is required to reduce these sulfur compounds as much as possible in order to prevent poisoning of the catalyst as described above. Therefore, a desulfurization process is performed using a conventionally known desulfurizing agent. One kind of desulfurization agent may be used, or a combination of desulfurization agents having different adsorption characteristics for each sulfur compound may be used. In order to maximize performance, it is desirable to use liquefied petroleum gas or the like having as low a sulfur content as possible.

  The desulfurizing agent containing zeolite used in the present invention (hereinafter sometimes referred to as desulfurizing agent A) is not particularly limited, and a conventionally known desulfurizing agent can be used. , X-type, Y-type zeolite, etc., using one or a combination of two or more as a carrier, Ag component, Cu component, Ni component, Zn component, Mn component, Fe component, Co component, alkali metal component, alkali Preferred are those carrying at least one metal component selected from among earth metal components and rare earth metal components. Here, preferred examples of the alkali metal component include potassium and sodium, examples of the alkaline earth metal component include calcium and magnesium, and examples of the rare earth metal component include lanthanum and cerium. Among these metal components, an Ag component and / or a Cu component are particularly preferable.

The desulfurizing agent A can be prepared by supporting the metal component on the zeolite. Specifically, an aqueous solution containing a water-soluble compound of a target metal component is brought into contact with a zeolite by a stirring method, an impregnation method, a distribution method, etc., and then washed with water and then dried and fired. It is done.
The content of the metal component in the desulfurizing agent A thus obtained is usually 1 to 40% by mass, preferably 5 to 30% by mass as a metal.

A desulfurization agent comprising at least one selected from metal elements, metal oxides and metal component-supported oxides (hereinafter sometimes referred to as desulfurization agent B) is an Ag component, a Cu component, a Ni component, a Zn component, or a Mn component. A desulfurizing agent containing at least one metal component selected from among Fe component, Co component, Si component, Al component, alkali metal component, alkaline earth metal component and rare earth metal component is preferable. Here, preferred examples of the alkali metal component include potassium and sodium, examples of the alkaline earth metal component include calcium and magnesium, and examples of the rare earth metal component include lanthanum and cerium.
The desulfurizing agent B is preferably a porous inorganic oxide carrier on which each metal component is supported, and in particular, one in which at least one of an Ag component, a Cu component and a Ni component is supported is preferable. Each metal component can be supported by a normal supporting method such as a coprecipitation method or an impregnation method.

Examples of the porous inorganic oxide carrier include at least one selected from silica, alumina, silica-alumina, titania, zirconia, magnesia, diatomaceous earth, white clay, clay, and zinc oxide. Among these, the alumina carrier, silica A car alumina support is preferred.
Below, the preparation method of the Ni-Cu type | system | group desulfurization agent which uses the suitable silica alumina as a support | carrier as this desulfurization agent B is demonstrated.
In the desulfurizing agent B, from the viewpoint of desulfurization performance and mechanical strength of the desulfurizing agent, the supported total metal content (as oxide) is usually 5 to 90% by mass, and the support is 95 to 10% by mass. The range is preferable, and the total metal content (as oxide) is 40 to 90% by mass, more preferably 70 to 90% by mass when supported by the coprecipitation method, and 5 to 5 when supported by the impregnation method. It is preferable that it is 40 mass%.
First, an acidic aqueous solution or aqueous dispersion containing a nickel source, a copper source and / or an aluminum source, and a basic aqueous solution containing a silicon source and an inorganic base are prepared. Examples of the nickel source used in the former acidic aqueous solution or aqueous dispersion include nickel chloride, nickel nitrate, nickel sulfate, nickel acetate, nickel carbonate and hydrates thereof, and examples of the copper source include copper chloride, Examples thereof include copper nitrate, copper sulfate, copper acetate, and hydrates thereof. These nickel sources and copper sources may be used alone or in combination of two or more.

  Examples of the aluminum source include hydrated alumina such as pseudo boehmite, boehmite alumina, bayerite, and gypsite, and γ-alumina. Among these, pseudo boehmite, boehmite alumina, and γ-alumina are preferable. These can be used in the form of powder or sol. Moreover, this aluminum source may use 1 type, and may be used in combination of 2 or more type.

On the other hand, the silicon source used in the basic aqueous solution is not particularly limited as long as it is soluble in an alkaline aqueous solution and becomes silica upon firing. For example, orthosilicic acid, metasilicic acid, and their sodium salts A potassium salt, water glass, etc. are mentioned. These may be used singly or in combination of two or more, but water glass which is a kind of sodium silicate hydrate is particularly suitable.
The inorganic base is preferably an alkali metal carbonate or hydroxide, and examples thereof include sodium carbonate, potassium carbonate, sodium hydroxide, and potassium hydroxide. One of these may be used, or two or more may be used in combination, but sodium carbonate alone or a combination of sodium carbonate and sodium hydroxide is particularly suitable. The amount of the inorganic base used is advantageously selected so that, when the acidic aqueous solution or aqueous dispersion and the basic aqueous solution are mixed in the next step, the mixed solution is substantially neutral to base. .
In addition, the inorganic base may be used in the total amount for the preparation of the basic aqueous solution, or a part thereof may be added to the acidic aqueous solution or the mixture of the aqueous dispersion and the basic aqueous solution in the next step. May be.

The acidic aqueous solution or aqueous dispersion thus prepared and the basic aqueous solution are each heated to about 50 to 90 ° C., and then both are mixed. After mixing, if necessary, an aqueous solution containing an inorganic base heated to 50 to 90 ° C. is further added, and the mixture is stirred at a temperature of about 50 to 90 ° C. for about 0.5 to 3 hours to react. To complete.
Next, the produced solid is sufficiently washed and separated into solid and liquid, or the produced solid is separated into solid and liquid and then washed sufficiently, and then this solid is obtained at a temperature of about 80 to 150 ° C. by a known method. Dry at a temperature of The desulfurization agent B in which the nickel component and the copper component are supported on the carrier is obtained by firing the dried product thus obtained, preferably at a temperature in the range of 200 to 400 ° C. When the firing temperature is out of the above range, it is difficult to obtain a Ni—Cu desulfurizing agent having desired performance.

Next, a method for preparing a silver-supported desulfurizing agent using alumina as a carrier suitable as the desulfurizing agent B will be described.
From the viewpoint of desulfurization performance, the supported amount of silver component is preferably in the range of 5 to 30 mass%. An aqueous solution containing a silver source is prepared. Examples of the silver source include silver nitrate, silver acetate, and silver sulfate. These silver sources may be used alone or in combination. Examples of the alumina include γ-type, φ-type, χ-type, δ-type, and η-type alumina, and γ-type, χ-type, and η-type are preferably used. A desulfurization agent in which an aqueous solution containing the silver source is impregnated and supported on alumina, dried at a temperature of about 80 to 150 ° C., and then fired at a temperature of about 200 to 400 ° C. to support a silver component on an alumina carrier. B is obtained.

Further, as desulfurization conditions of the present invention, the normal temperature is selected in the range of −20 to 100 ° C., and the GHSV (gas hourly space velocity) is 100 to 1,000,000 h ⁻¹ , preferably 100 to 100,000 h ^{−. 1} , more preferably selected in the range of 100 to 30,000 h ⁻¹ .

Next, in the method for producing hydrogen used in the fuel cell system of the present invention, the desulfurized liquefied petroleum gas is converted into a partial oxidation reforming catalyst, an autothermal reforming catalyst, a steam reforming catalyst, or a carbon dioxide reforming catalyst. By contacting them, hydrogen is produced by partial oxidation reforming, autothermal reforming, steam reforming or carbon dioxide reforming, respectively.
In this reforming treatment, the concentration of the sulfur compound in the desulfurized liquefied petroleum gas is preferably 0.05 mass ppm or less, particularly preferably 0.02 mass ppm or less, from the viewpoint of the life of each reforming catalyst. .
The partial oxidation reforming is a method for producing hydrogen by partial oxidation reaction of a hydrocarbon compound of liquefied petroleum gas, and in the presence of a partial oxidation reforming catalyst, the reaction pressure is usually from normal pressure to 5 MPa · G. The reforming reaction is performed under the conditions of a temperature of 400 to 1,100 ° C., a GHSV of 1,000 to 100,000 h ⁻¹ , and an oxygen (O ₂ ) / carbon molar ratio of 0.2 to 0.8.
Autothermal reforming is a method in which partial oxidation reforming and steam reforming are combined. In the presence of an autothermal reforming catalyst, the reaction pressure is usually from normal pressure to 5 MPa · G, and the reaction temperature is from 400 to 1. , 100 ° C., oxygen (O ₂ ) / carbon molar ratio 0.1 to 1, steam / carbon molar ratio 0.1 to 10, and GHSV 1,000 to 100,000 h ⁻¹ .

Further, steam reforming is a method for producing hydrogen by bringing a hydrocarbon compound into contact with steam, and in the presence of a steam reforming catalyst, usually a reaction pressure of normal pressure to 3 MPa · G, a reaction temperature of 200 to 900. The reforming reaction is performed under the conditions of ° C., steam / carbon molar ratio of 1.5 to 10, and GHSV of 1,000 to 100,000 h ⁻¹ .
Carbon dioxide reforming is a method for producing hydrogen by causing a reaction between a hydrocarbon compound and carbon dioxide. The reaction conditions for hydrogen production are usually 200 to 1,300 ° C., preferably 400. It is -1200 degreeC, More preferably, it is 500-900 degreeC. The carbon dioxide / carbon molar ratio is usually 0.1 to 5, preferably 0.1 to 3. When steam is added, the steam / carbon molar ratio is usually 0.1 to 10, preferably 0.4 to 4. When oxygen is added, the oxygen / carbon molar ratio is usually 0.1 to 1, preferably 0.2 to 0.8. The reaction pressure is usually 0 to 10 MPa · G, preferably 0 to 5 MPa · G, more preferably 0 to 3 MPa · G. About GHSV, it is the same as that of the case of the said steam reforming.

  As the partial oxidation reforming catalyst, autothermal reforming catalyst, steam reforming catalyst and carbon dioxide reforming catalyst, any of the conventionally known catalysts can be appropriately selected and used. Nickel-based catalysts are preferred. Moreover, as a support | carrier of these catalysts, the support | carrier containing at least 1 type chosen from manganese oxide, a cerium oxide, and a zirconia can be mentioned preferably. The carrier may be a carrier composed of only these metal oxides, or may be a carrier obtained by adding the above metal oxide to another refractory porous inorganic oxide such as alumina.

  The reaction system for the above reforming reaction may be either a continuous flow system or a batch system, but a continuous flow system is preferred.

The reaction format is not particularly limited, and any of a fixed bed type, a moving bed type and a fluidized bed type can be adopted, but a fixed bed type is preferred. There is no restriction | limiting in particular also as a form of a reactor, For example, a tubular reactor etc. can be used.
Hydrogen can be obtained by performing the steam reforming reaction, autothermal reforming reaction, partial oxidation reforming reaction, carbon dioxide reforming reaction of hydrocarbon compounds using the reforming catalyst under the above conditions. It is preferably used in a hydrogen production process of a fuel cell.

The fuel cell system of the present invention includes a desulfurizer provided with a desulfurizing agent, a reformer provided with a reforming catalyst, a CO shift catalyst, and the like, and a fuel cell using hydrogen produced by the reformer as fuel. It is characterized by having. This fuel cell system will be described with reference to FIG.
The fuel in the liquefied petroleum gas cylinder 21 is introduced into the desulfurizer 23 via the fuel supply line 22 by a vaporization method. The desulfurizer 23 is filled with the desulfurizing agent A and / or the desulfurizing agent B, for example. The fuel desulfurized by the desulfurizer 23 is mixed with water from the water tank via the water pump 24, and then mixed with the air sent from the air blower 35 and sent to the reformer 31. The reformer 31 is filled with a reforming catalyst, and hydrogen is produced from the fuel mixture (mixed gas containing hydrocarbon compound, water vapor and oxygen) sent to the reformer 31 by any of the reforming reactions described above. Is manufactured.
Reference numeral 38 denotes a flow rate adjusting valve.

  The hydrogen produced in this way is reduced to the extent that the CO concentration does not reach the characteristics of the fuel cell through the CO converter 32 and the CO selective oxidizer 33. Examples of catalysts used in these reactors include an iron-chromium-based catalyst, a copper-zinc-based catalyst, or a noble metal-based catalyst for the CO converter 32, and a ruthenium-based catalyst, platinum for the CO selective oxidizer 33. Examples thereof include a system catalyst or a mixed catalyst thereof. When the CO concentration in the hydrogen produced by the reforming reaction is low, the CO converter 32 and the CO selective oxidizer 33 may not be attached.

The fuel cell 34 is an example of a polymer electrolyte fuel cell including a polymer electrolyte 34C between a negative electrode 34A and a positive electrode 34B. The hydrogen-rich gas obtained by the above method is introduced into the negative electrode side, and the air sent from the air blower 35 is introduced into the positive electrode side after performing appropriate humidification treatment if necessary (humidifier not shown). Is done.
At this time, a reaction in which hydrogen gas becomes protons and emits electrons proceeds on the negative electrode side, and a reaction in which oxygen gas obtains electrons and protons to become water proceeds on the positive electrode side, and a direct current is generated between both electrodes 34A and 34B. To do. In that case, platinum black or an activated carbon-supported Pt catalyst or Pt-Ru alloy catalyst is used for the negative electrode, and platinum black or an activated carbon-supported Pt catalyst is used for the positive electrode.

  The surplus hydrogen can be used as fuel by connecting the burner 31A of the reformer 31 to the negative electrode 34A side. In addition, an air / water separator 36 is connected to the positive electrode 34B side, water and exhaust gas generated by the combination of oxygen and hydrogen in the air supplied to the positive electrode 34B side are separated, and water is used to generate water vapor. can do. Since heat is generated in the fuel cell 34 with power generation, an exhaust heat recovery device 37 can be attached to recover the heat for effective use. The exhaust heat recovery device 37 is attached to the fuel cell 34 to deprive the heat generated during the reaction, a heat exchanger 37A, a heat exchanger 37B for exchanging the heat deprived by the heat exchanger 37A with water, 37C and a heat pump 37D that circulates the refrigerant to the heat exchangers 37A and 37B and the cooler 37C, and the hot water obtained in the heat exchanger 37B can be effectively used in other facilities.

  EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by these examples.

  2 kg of a β-zeolite (“HSZ-930NHA” manufactured by Tosoh Corporation) burned at 500 ° C. and 350 g of silver nitrate (made by Wako Pure Chemical Industries, Ltd., special grade) are poured into an aqueous solution prepared by dissolving in 10 liters of water, Ion exchange was performed by stirring for 4 hours. Thereafter, the solid was washed with water, collected by filtration, dried at 120 ° C. for 12 hours with a blower, and calcined at 400 ° C. for 3 hours to obtain a desulfurization agent A containing 6% by mass of Ag.

(2) Preparation of desulfurizing agent B 7300 g of nickel sulfate hexahydrate (manufactured by Wako Pure Chemical Industries, Ltd., special grade) and 1513 g of copper sulfate pentahydrate (manufactured by Wako Pure Chemical Industries, Ltd., special grade) After being dissolved in 80 liters of water heated to 80 ° C., 160 g of pseudo boehmite (Catalyst Chemical Industries, Ltd., “C-AP”, 67% by mass as Al ₂ O ₃ ) was mixed. The pH was adjusted to 2 by adding 3 liters of 5 mol / liter sulfuric acid aqueous solution (preparation solution A). Further, 6000 g of sodium carbonate was dissolved in 80 liters of water heated to 80 ° C., and 1802 g of water glass (manufactured by Nippon Chemical Industry Co., Ltd., “J-1”, Si concentration 29 mass%) was added (preparation solution) B). The preparation liquid A and the preparation liquid B were mixed while being kept at 80 ° C. and stirred for 1 hour. Thereafter, the precipitated cake is washed with 600 liters of water, filtered, dried at 120 ° C. for 12 hours in a blow dryer, and further calcined at 350 ° C. for 3 hours, whereby Ni 50 mass% and Cu 13 mass%. A desulfurizing agent B containing was obtained.

Example 1
In a stainless steel desulfurizer with a diameter of 2 cm, 20 ml of desulfurizing agent A was weighed and filled. The temperature of the desulfurizer is 20 ° C., and under normal pressure, sulfur concentration of carbonyl sulfide, dimethyl sulfide, dimethyl disulfide, and tertiary mercaptan is 1.25 mass ppm, desulfurized propane (manufactured by Takachiho Chemical Co., Ltd.) 80% by volume. , Desulfurized butane (manufactured by Takachiho Chemical Industry Co., Ltd .: isobutane 57 vol%, normal butane 43 vol%) 20% by volume, and further diluted with desulfurized propane, methanol is 12 mass ppm with respect to the total supply amount It added so that it might become. The gas thus prepared was circulated under normal pressure, a temperature of 20 ° C., and a GHSV (gas space velocity) of 400 h ⁻¹ . The sulfur concentration at the outlet of the desulfurizer was analyzed every 3 to 4 days. As a result, after 4150 hours, the sulfur concentration (excluding carbonyl sulfide) reached 0.05 mass ppm.

Example 2
The same test as in Example 1 was performed except that 20 ml of desulfurizing agent B was filled. As a result, after 2930 hours, the total sulfur concentration reached 0.05 mass ppm.

Example 3
The same test as in Example 1 was performed except that the amount of methanol in the raw material LP gas was adjusted to 25 mass ppm. As a result, after 3950 hours, the sulfur concentration excluding carbonyl sulfide reached 0.05 mass ppm.

Example 4
The same test as in Example 3 was performed except that 20 ml of the desulfurizing agent B was charged and the amount of methanol in the raw material LP gas was adjusted to 25 ppm by mass. As a result, after 2800 hours, the sulfur concentration reached 0.05 mass ppm.

Reference example 1
The same test as in Example 1 was performed except that methanol was not added. As a result, after 4200 hours, the sulfur concentration reached 0.05 mass ppm.

Reference example 2
The same test as in Example 2 was performed except that methanol was not added. As a result, after 3000 hours, the sulfur concentration reached 0.05 mass ppm.

Comparative Example 1
A test similar to Example 1 was performed except that the amount of methanol in the raw material LP gas was adjusted to 75 ppm by mass. As a result, after 2500 hours, the sulfur concentration reached 0.05 mass ppm.

Comparative Example 2
The same test as in Example 2 was performed except that the amount of methanol in the raw material LP gas was adjusted to 75 ppm by mass. As a result, after 900 hours, the sulfur concentration reached 0.05 mass ppm.

It is an example of the general | schematic flowchart of the fuel cell system of this invention.

Explanation of symbols

1: Fuel cell system 11: Water supply pipe 12: Fuel introduction pipe 20: Hydrogen production system 21: Liquefied petroleum gas cylinder 22: Fuel supply line 23: Desulfurizer 24: Water pump 31: Reformer 31A: Reformer burner 32: CO converter 33: CO selective oxidizer 34: Fuel cell 34A: Fuel cell negative electrode 34B: Fuel cell positive electrode 34C: Fuel cell polymer electrolyte 35: Air blower 36: Air / water separator 37: Waste heat recovery device 37A: Heat exchanger 37B: Heat exchanger 37C: Cooler 37D: Refrigerant circulation pump 38: Flow control valve

Claims (7)

In a fuel cell system using liquefied petroleum gas added with methanol to prevent condensation , the content of hydrocarbon compounds having 2 carbon atoms is 5% by volume or less, and the content of hydrocarbon compounds having 4 carbon atoms is 25% by volume. A liquefied petroleum gas comprising a hydrocarbon compound having a methanol content of 30 ppm by mass or less and a residue of 3 carbon atoms is supplied to the desulfurization process as a gaseous fuel. system.   The fuel cell system according to claim 1, wherein the methanol content is 15 mass ppm or less. The fuel cell system according to claim 1, wherein the gaseous liquefied petroleum gas is used after being desulfurized with a desulfurizing agent containing zeolite.   The fuel cell system according to claim 3, wherein the zeolite has a beta (BEA) and / or faujasite (FAU) structure.   The desulfurizing agent containing zeolite is selected from the group consisting of Ag component, Cu component, Ni component, Zn component, Mn component, Fe component, Co component, alkali metal component, alkaline earth metal component and rare earth metal component together with zeolite. The fuel cell system according to claim 3 or 4, comprising at least one metal component. 2. The fuel cell system according to claim 1, wherein the gaseous liquefied petroleum gas is used after being subjected to a desulfurization treatment with a desulfurization agent made of at least one selected from a metal element, a metal oxide, and a metal component-supported oxide.   A desulfurization agent comprising at least one selected from metal elements, metal oxides and metal component-supported oxides is an Ag component, Cu component, Ni component, Zn component, Mn component, Fe component, Co component, Si component, Al The fuel cell system according to claim 6, comprising at least one metal component selected from the group consisting of a component, an alkali metal component, an alkaline earth metal component, and a rare earth metal component.

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