JP4210130B2 - Hydrocarbon desulfurization catalyst, desulfurization method, and fuel cell system - Google Patents

Description

【００４３】
（実施例３）
図１の燃料電池システムにおいて、脱硫器５に、実施例１で得られた触媒（１）を充填して、１号灯油（硫黄濃度：２３質量ｐｐｍ）を燃料とし、発電試験を行なった。１５０時間の運転中、脱硫器は正常に作動し、触媒の活性低下は認められなかった。脱硫条件は、温度１８０℃、常圧、水素流通なし、ＬＨＳＶ＝０．５ｈ^-1であった。
このとき水蒸気改質にはＲｕ系触媒を用い、Ｓ／Ｃ＝３、温度７００℃、ＬＨＳＶ＝５ｈ^-1の条件で、シフト工程（反応器１０）では銅−亜鉛系触媒を用い、２００℃、ＧＨＳＶ＝２０００ｈ^-1の条件で、一酸化炭素選択酸化工程（反応器１１）ではＲｕ系触媒を用い、Ｏ₂／ＣＯ＝３、温度１５０℃、ＧＨＳＶ＝５０００ｈ^-1の条件で運転を行った。燃料電池も正常に作動し電気負荷１５も順調に運転された。
【図面の簡単な説明】
【図１】本発明の燃料電池システムの一例を示す概略図である。
【符号の説明】
１ 水タンク
２ 水ポンプ
３ 燃料タンク
４ 燃料ポンプ
５ 脱硫器
６ 気化器
７ 改質器
８ 空気ブロアー
９ 高温シフト反応器
１０ 低温シフト反応器
１１ 一酸化炭素選択酸化反応器
１２ アノード
１３ カソード
１４ 固体高分子電解質
１５ 電気負荷
１６ 排気口
１７ 固体高分子形燃料電池
１８ 加温用バーナー[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a hydrocarbon desulfurization catalyst. The present invention also relates to a method for desulfurizing hydrocarbons containing sulfur using the catalyst. Furthermore, the present invention relates to a fuel cell system provided with a desulfurization device filled with the catalyst.
[0002]
[Prior art]
A fuel cell has a feature that high efficiency can be obtained because a free energy change caused by a combustion reaction of fuel can be directly taken out as electric energy. In addition to the fact that it does not emit harmful substances, it is being developed for various uses. In particular, solid polymer fuel cells are characterized by high power density, compactness, and operation at low temperatures.
[0003]
As a fuel gas for a fuel cell, a gas containing hydrogen as a main component is generally used. The raw material is a hydrocarbon such as natural gas, LPG, naphtha or kerosene, alcohol such as methanol or ethanol, or dimethyl ether. Etc. are used. These raw materials containing carbon and hydrogen are reformed by treating them with steam at a high temperature on a catalyst, partially oxidized with an oxygen-containing gas, or a self-heat recovery type reforming reaction in a system in which steam and an oxygen-containing gas coexist. The hydrogen obtained by performing is basically used as fuel hydrogen for fuel cells.
[0004]
However, since elements other than hydrogen exist in these raw materials, it is inevitable that impurities derived from carbon are mixed in the fuel gas to the fuel cell. For example, carbon monoxide poisons platinum-based noble metals used as electrode catalysts for fuel cells. Therefore, if carbon monoxide is present in the fuel gas, sufficient power generation characteristics cannot be obtained. In particular, a fuel cell operated at a low temperature has a stronger carbon monoxide adsorption and is more susceptible to poisoning. Therefore, in a system using a polymer electrolyte fuel cell, it is indispensable that the concentration of carbon monoxide in the fuel gas is reduced.
[0005]
For this reason, a method is adopted in which carbon monoxide in the reformed gas obtained by reforming the raw material is reacted with water vapor, converted into hydrogen and carbon dioxide, and a small amount of remaining carbon monoxide is removed by selective oxidation. .
Finally, the fuel hydrogen removed until the carbon monoxide concentration is sufficiently low is introduced into the cathode of the fuel cell where it is converted into protons and electrons on the electrocatalyst. The produced protons move to the anode side in the electrolyte, react with oxygen together with the electrons that have passed through the external circuit, and produce water. Electrons generate electricity by passing through an external circuit.
[0006]
The catalyst used for the raw material reforming and carbon monoxide removal steps for producing fuel hydrogen for fuel cells and the cathode electrode is often used in a reduced state such as noble metal or copper. Then, sulfur acts as a catalyst poison, and there is a problem that the catalytic activity of the hydrogen production process or the battery itself is lowered and the efficiency is lowered.
Therefore, it is considered that it is indispensable to sufficiently remove the sulfur content contained in the raw material in order to use the catalyst used in the hydrogen production process and further the electrode catalyst in its original performance.
The so-called desulfurization process, which basically removes sulfur, takes place at the very beginning of the hydrogen production process. Although it is necessary to reduce the sulfur concentration to a level at which the catalyst used in the reforming process immediately after that functions sufficiently, it is usually 0.1 ppm by mass or less.
[0007]
Until now, the sulfur content of fuel cell raw materials has been removed by hydrodesulfurizing difficult-to-desulfurize organic sulfur compounds with a desulfurization catalyst, once converted to hydrogen sulfide that can be easily adsorbed and removed, and treated with an appropriate adsorbent. It seemed that the method to do was suitable. However, a general hydrodesulfurization catalyst is used at a high hydrogen pressure. However, when it is used in a fuel cell system, since the technological development is limited to atmospheric pressure or at most 1 MPa, an ordinary desulfurization catalyst is used. The current situation is that the system cannot handle it.
[0008]
For this reason, studies have been made on catalyst systems that can sufficiently exhibit a desulfurization function even in a low-pressure system. For example, a method for producing hydrogen by steam reforming kerosene desulfurized with a nickel-based desulfurizing agent has been proposed (see, for example, Patent Document 1 and Patent Document 2). However, this method has a process limitation that the temperature range in which desulfurization is possible is 150 to 300 ° C. Further, proposals have been made for copper-zinc-based desulfurization catalysts (see, for example, Patent Document 3 and Patent Document 4). However, although this catalyst has little carbon deposition even when used at relatively high temperatures, desulfurization activity is lower than that of nickel, so light hydrocarbons such as natural gas, LPG and naphtha can be desulfurized. There is a problem that it is insufficient. In addition, a method using activated carbon or a chemical solution for desulfurization is proposed (see Patent Document 5). However, this catalyst has been shown to have a desulfurization effect at normal temperature at start-up, but the raw material is limited to a gas body at normal temperature. A nickel-zinc catalyst has also been proposed (see Patent Document 6), but is premised on coexistence with hydrogen and use under pressure. Under non-coexistence conditions, the nickel content is low and the catalyst performance decreases. .
[0009]
[Patent Document 1]
JP-A-1-188404
[Patent Document 2]
Japanese Patent Laid-Open No. 1-188405
[Patent Document 3]
JP-A-2-302302
[Patent Document 4]
JP-A-2-302303
[Patent Document 5]
Japanese Patent Laid-Open No. 1-143155
[Patent Document 6]
JP 2001-62297 A
[0010]
[Problems to be solved by the invention]
As described above, the reforming of raw materials until the production of fuel hydrogen for fuel cells, the removal of carbon monoxide, and the catalyst used for the cathode electrode are often used in the reduced state of noble metals or copper, In such a state, sulfur acts as a catalyst poison, reducing the catalytic activity of the hydrogen production process or the battery itself, and reducing the efficiency. Therefore, it is indispensable to sufficiently remove the sulfur contained in the raw material in order to use the catalyst used in the hydrogen production process and further the electrode catalyst with its original performance. In addition, it is necessary to effectively desulfurize hardly desulfurization substances under low pressure conditions.
[0011]
[Means for Solving the Problems]
As a result of diligent research on this problem, the present inventors have found a catalyst that efficiently desulfurizes sulfur contained in hydrocarbons, and have completed the present invention. The present invention also provides a desulfurization method using this specific catalyst and a fuel cell system having a desulfurization apparatus using this catalyst.
[0012]
That is, the first of the present invention is obtained by calcining a catalyst precursor in which a component containing nickel and zinc is formed by coprecipitation using at least one alumina selected from γ-alumina, β-alumina and pseudoboehmite as a core. The present invention relates to a hydrocarbon desulfurization catalyst containing 30 to 80% by mass of nickel oxide, 10 to 70% by mass of zinc oxide and 0.1 to 40% by mass of alumina.
[0013]
In addition, a second aspect of the present invention relates to a hydrocarbon desulfurization method characterized by desulfurizing a hydrocarbon containing sulfur to a sulfur concentration of 0.1 mass ppm or less using the catalyst.
[0014]
Furthermore, a third aspect of the present invention is a desulfurization apparatus that desulfurizes hydrocarbons containing sulfur, and a hydrocarbon desulfurized by the desulfurization apparatus. The present invention relates to a fuel cell system having at least a reformer for reforming the fuel gas.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
The present invention is described in detail below.
The desulfurization catalyst of the present invention can be obtained by calcining a catalyst precursor formed by coprecipitation with a component containing nickel and zinc with alumina as a nucleus.
As the alumina, at least one selected from γ-alumina, β-alumina and pseudoboehmite is used.
The particle size of the alumina used is preferably 1000 μm or less, preferably 500 μm or less, more preferably 200 μm or less in powder form, and if necessary, it is used after pulverization. If the particle size of the alumina is larger than 1000 microns, it becomes difficult for the alumina itself to exist uniformly in the system, and uniform precipitation on the alumina is hindered. Although there is no restriction | limiting in particular about the minimum of a particle size, Usually, it is 1 nm or more, Preferably the powdery thing which consists of particle | grains of 10 nm or more is preferable.
[0016]
Specifically, a coprecipitation method in which a component containing nickel and zinc is formed using alumina as a core is specifically prepared by suspending alumina in an aqueous solution of a nickel compound and a zinc compound and mixing the base with the suspension, or A catalyst precursor is formed by suspending alumina in an aqueous solution and mixing an aqueous solution of nickel compound and zinc compound with the suspension to cause precipitation of the nickel compound and zinc compound on the alumina.
As the nickel compound and zinc compound, respective chlorides, nitrates, sulfates, organic acid salts, hydroxides and the like can be used. Specifically, nickel chloride, nickel nitrate, nickel sulfate, nickel acetate, nickel hydroxide, zinc chloride, zinc nitrate, zinc sulfate, zinc acetate, zinc hydroxide and the like are preferable.
As the base, an aqueous solution of ammonia, sodium carbonate, sodium hydrogen carbonate, potassium carbonate or the like can be used.
[0017]
After making the nickel compound and the zinc compound precipitate on the alumina using alumina as a nucleus, the produced precipitation product (catalyst precursor) is filtered and washed with ion-exchanged water or the like. Insufficient cleaning leaves chlorine, nitric acid traces, sulfuric acid traces, acetic acid traces, sodium, potassium, etc. on the catalyst, which adversely affects catalyst performance. When ion-exchanged water cannot be sufficiently washed, an aqueous solution of a base such as ammonia, sodium carbonate, sodium hydrogen carbonate, or potassium carbonate may be used as the washing liquid. In this case, it is preferable to first wash the precipitated product with an aqueous base solution, and then wash with ion-exchanged water.
After washing the precipitated product, the precipitated product is pulverized and then dried. After drying, baking is subsequently performed. If washing after precipitation is insufficient, washing may be performed again after firing. Also in this case, ion-exchanged water or an aqueous solution of the base described above can be used.
[0018]
The drying method is not particularly limited, and examples thereof include natural drying in air and deaeration drying under reduced pressure. Usually, drying is performed at 100 to 150 ° C. for 5 to 15 hours in an air atmosphere. The firing method is not particularly limited, and the firing is usually performed in an air atmosphere at 200 to 600 ° C., preferably 250 to 450 ° C. for 0.1 to 10 hours, preferably 1 to 5 hours. desirable.
[0019]
The catalyst of the present invention obtained by calcining the above-described catalyst precursor contains nickel oxide, zinc oxide and alumina as constituent components.
The content of nickel oxide in the catalyst is 30 to 80% by mass, preferably 40 to 80% by mass, and more preferably 45 to 80% by mass. When the content of nickel oxide in the catalyst is less than 30% by mass, the catalyst performance becomes insufficient. On the other hand, when the content of nickel oxide in the catalyst exceeds 80% by mass, the dispersibility of nickel is lowered, and not only the catalyst performance is lowered, but also economically undesirable.
The content of zinc oxide in the catalyst is 10 to 70% by mass, preferably 10 to 60% by mass, and more preferably 15 to 50% by mass. When the content of zinc oxide in the catalyst is less than 10% by mass, the catalyst performance is insufficient, and when it exceeds 70% by mass, the nickel content is relatively decreased, and the catalyst performance is lowered.
Content of the alumina in a catalyst is 0.1-40 mass%, Preferably it is 0.5-35 mass%, More preferably, it is 1-30 mass%. When the content of alumina in the catalyst is less than 0.1% by mass, the catalyst performance becomes insufficient. When the content exceeds 40% by mass, the nickel content is relatively decreased, and the catalyst performance is lowered.
[0020]
When the catalyst prepared by the above method is used, it can be subjected to the reaction as it is, but a reduction treatment with hydrogen or the like may be performed as a pretreatment. As the conditions, the temperature is 150 to 500 ° C, preferably 250 to 400 ° C, and the time is 0.1 to 15 hours, preferably 2 to 10 hours.
[0021]
The shape of the catalyst of the present invention is not particularly limited, and the catalyst obtained as a powder may be used as it is, or may be formed into a molded product by tableting. A catalyst that has been sized in an appropriate range after pulverization may be used. Further, an extruded catalyst can be used. In molding, an appropriate binder may be added. The binder is not particularly limited, and carbon black, alumina, silica, titania, zirconia, or a composite oxide thereof can be used. As for the addition amount of a binder, an upper limit is 50 mass% or less normally, Preferably it is 30 mass% or less. The lower limit is not particularly limited as long as it can function as a binder, and is usually 1% by mass or more, and preferably 5% by mass or more.
[0022]
A second aspect of the present invention is a hydrocarbon desulfurization method, characterized in that a sulfur-containing hydrocarbon is desulfurized to a sulfur concentration of 0.1 mass ppm or less using the first catalyst of the present invention. In particular, the desulfurization method of the present invention is characterized in that the sulfur concentration can be desulfurized to 0.1 mass ppm or less under non-coexisting conditions.
The hydrocarbon containing sulfur used in the present invention is not particularly limited, and examples thereof include methane, ethane, propane, butane, natural gas, LPG, naphtha, gasoline, kerosene, and mixtures thereof. The raw material hydrocarbon may contain hydrogen, and various alcohols, ethers, and the like may be contained. These raw material hydrocarbons may be liquid or gas.
These hydrocarbons used in the present invention contain a small amount of sulfur, and the amount varies depending on the production method, but usually contains more than 0.1 ppm by mass and less than 100 ppm by mass. Yes. The sulfur content of the present invention is a generic term for various sulfur, inorganic sulfur compounds, and organic sulfur compounds that are usually contained in these hydrocarbons.
[0023]
The pressure in the desulfurization reaction is preferably a low pressure in the range of normal pressure to 1 MPa, and more preferably normal pressure to 0.2 MPa in consideration of the economics and safety of the fuel cell system. The reaction temperature is not particularly limited as long as it is a temperature that lowers the sulfur concentration, but it is preferable to work effectively from room temperature in consideration of the start of the equipment, and in consideration of the steady state, 10 ° C. to 450 ° C. is preferable. More preferably, 15 to 350 ° C, particularly preferably 20 to 300 ° C is employed. If the SV is too high, the desulfurization reaction does not proceed easily. On the other hand, if the SV is too low, the apparatus becomes large. When using liquid raw materials, 0.01 to 15 hours ^-1 Is preferably in the range of 0.05 to 5 h ^-1 Is more preferable, 0.1-3h ^-1 The range of is particularly preferable. 100 to 10000 hours when using gas fuel ^-1 Is preferably in the range of 200 to 5000 h ^-1 More preferably, the range of 300-2000h ^-1 The range of is particularly preferable. The desulfurization method of the present invention is characterized in that it can be desulfurized under non-hydrogen coexistence conditions, but a small amount of hydrogen may be introduced. The flow rate of hydrogen at that time is, for example, 0.05 to 1.0 NL per 1 g of hydrocarbon raw material.
[0024]
Although the form of the desulfurization apparatus using the desulfurization method of this invention is not specifically limited, For example, a flow-type fixed bed system can be used. The shape of the desulfurization device can be any known shape depending on the purpose of each process, such as a cylindrical shape or a flat plate shape.
[0025]
By using the desulfurization catalyst of the present invention, the sulfur concentration of the hydrocarbon containing the above-described sulfur content can be reduced to 0.1 mass ppm or less under non-coexisting conditions of hydrogen. The sulfur concentration is measured by an ultraviolet fluorescence method.
For hydrocarbons desulfurized to a sulfur concentration of 0.1 mass ppm or less, use the hydrogen-rich gas produced as the fuel for fuel cells through the reforming step, shift step, carbon monoxide selective oxidation step, etc. Can do.
[0026]
The reforming process is not particularly limited, but steam reforming in which the raw material is reformed with steam at a high temperature on a catalyst, partial oxidation with an oxygen-containing gas, and steam and an oxygen-containing gas coexist. In such a system, autothermal reforming that performs a self-heat recovery type reforming reaction can be used.
The reaction conditions for the reforming are not limited, but the reaction temperature is preferably 200 to 1000 ° C, particularly preferably 500 to 850 ° C. The reaction pressure is preferably from normal pressure to 1 MPa, and particularly preferably from normal pressure to 0.2 MPa. LHSV is 0.01-40h ^-1 Is preferred, especially 0.1 to 10 h ^-1 Is preferred.
[0027]
The mixed gas containing carbon monoxide and hydrogen obtained at this time can be used as a fuel for a fuel cell as it is in the case of a solid oxide fuel cell. In addition, it can be suitably used as a raw material for hydrogen for a fuel cell, such as a phosphoric acid fuel cell or a polymer electrolyte fuel cell, in which carbon monoxide needs to be removed.
[0028]
The production of hydrogen for a fuel cell can employ a known method, and can be carried out, for example, by treating in a shift step and a carbon monoxide selective oxidation step.
The shift process is a process in which carbon monoxide and water are reacted to convert to hydrogen and carbon dioxide, and contains, for example, iron-chromium mixed oxide, copper-zinc mixed oxide, platinum, ruthenium, iridium, etc. The carbon monoxide content is reduced to 2 vol% or less, preferably 1 vol% or less, and more preferably 0.5 vol% or less.
Although the reaction conditions for the shift reaction are not necessarily limited by the reformed gas composition or the like as a raw material, the reaction temperature is preferably 120 to 500 ° C, and particularly preferably 150 to 450 ° C. The pressure is preferably normal pressure to 1 MPa, particularly preferably normal pressure to 0.2 MPa. GHSV is 100-50000h ^-1 Is preferred, especially 300-10000h ^-1 Is preferred. Usually, in the phosphoric acid fuel cell, the mixed gas in this state can be used as fuel.
[0029]
On the other hand, in the polymer electrolyte fuel cell, since it is necessary to further reduce the carbon monoxide concentration, it is desirable to provide a step of removing carbon monoxide. This step is not particularly limited, and various methods such as an adsorption separation method, a hydrogen separation membrane method, and a carbon monoxide selective oxidation step can be used. It is particularly preferable to use a carbon monoxide selective oxidation step. In this step, using a catalyst containing iron, cobalt, nickel, ruthenium, rhodium, palladium, osmium, iridium, platinum, copper, silver, gold, etc., 0.5 to 10 times the remaining number of moles of carbon monoxide Mole, preferably 0.7 to 5 times mole, more preferably 1 to 3 times mole oxygen is added to selectively convert carbon monoxide to carbon dioxide, thereby reducing the carbon monoxide concentration. Although the reaction conditions of this method are not limited, the reaction temperature is preferably 80 to 350 ° C, particularly preferably 100 to 300 ° C. The pressure is preferably normal pressure to 1 MPa, particularly preferably normal pressure to 0.2 MPa. GHSV is 1000-50000h ^-1 Is preferred, especially 3000-30000h ^-1 Is preferred. In this case, the carbon monoxide concentration can be reduced by reacting with the coexisting hydrogen simultaneously with the oxidation of carbon monoxide to generate methane.
[0030]
A third aspect of the present invention is a desulfurization apparatus that has a reaction part filled with the first desulfurization catalyst of the present invention and desulfurizes hydrocarbons containing sulfur, and hydrocarbons desulfurized by the desulfurization apparatus. A fuel cell system having at least a reforming device for reforming into a fuel gas containing hydrogen as a main component.
[0031]
An example of this fuel cell system will be described below with reference to FIG.
The raw fuel in the fuel tank 3 flows into the desulfurizer 5 through the fuel pump 4. At this time, if necessary, the hydrogen-containing gas from the carbon monoxide selective oxidation reactor 11 can be added. The desulfurizer 5 is filled with the desulfurization catalyst of the present invention. The fuel desulfurized in the desulfurizer 5 is mixed with water from the water tank 1 through the water pump 2, introduced into the vaporizer 6, and sent into the reformer 7.
[0032]
The reformer 7 is heated by a heating burner 18. As the fuel for the heating burner 18, the anode off gas of the fuel cell 17 is mainly used, but the fuel discharged from the fuel pump 4 can be supplemented as necessary. As the catalyst filled in the reformer 7, a nickel-based, ruthenium-based, or rhodium-based catalyst can be used.
The gas containing hydrogen and carbon monoxide produced in this way is passed through the high temperature shift reactor 9, the low temperature shift reactor 10, and the carbon monoxide selective oxidation reactor 11 in order, so that the carbon monoxide concentration is adjusted to the fuel cell. It is reduced to the extent that it does not affect the characteristics of Examples of catalysts used in these reactors include an iron-chromium catalyst for the high temperature shift reactor 9, a copper-zinc catalyst for the low temperature shift reactor 10, and a ruthenium catalyst for the carbon monoxide selective oxidation reactor 11. Etc.
[0033]
The polymer electrolyte fuel cell 17 includes an anode 12, a cathode 13, and a solid polymer electrolyte 14. The fuel gas containing high-purity hydrogen obtained by the above method is provided on the anode side, and the air blower is provided on the cathode side. If necessary, air sent from 8 is introduced after appropriate humidification processing (a humidifier is not shown). At this time, a reaction in which hydrogen gas becomes protons and emits electrons proceeds at the anode, and a reaction in which oxygen gas obtains electrons and protons to become water proceeds at the cathode. In order to promote these reactions, platinum black and Pt catalyst or Pt-Ru alloy catalyst supported on activated carbon are used for the anode, and platinum black and Pt catalyst supported on activated carbon are used for the cathode. Usually, both the anode and cathode catalysts are formed into a porous catalyst layer together with polytetrafluoroethylene, a low molecular weight polymer electrolyte membrane material, activated carbon, and the like as necessary.
[0034]
Next, the porous catalyst layer is laminated on both sides of a polymer electrolyte membrane known by a trade name such as Nafion (manufactured by DuPont), Gore (manufactured by Gore), Flemion (manufactured by Asahi Glass), Aciplex (manufactured by Asahi Kasei). An MEA (Membrane Electrode Assembly) is formed. Further, the fuel cell is assembled by sandwiching the MEA with a separator having a gas supply function, a current collecting function, particularly an important drainage function in the cathode, and the like made of a metal material, graphite, carbon composite and the like. The electric load 15 is electrically connected to the anode and the cathode.
The anode off gas is consumed in the heating burner 18. The cathode off gas is discharged from the exhaust port 16.
[0035]
【The invention's effect】
By using the desulfurization catalyst of the present invention, sulfur-containing hydrocarbons can be desulfurized under non-hydrogen coexistence conditions, and the sulfur concentration can be reduced to 0.1 mass ppm or less, and the resulting fuel gas is particularly solid. It can be suitably employed in a fuel cell system using a polymer fuel cell.
[0036]
【Example】
EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto.
[0037]
Example 1
Nickel acetate tetrahydrate (commercial reagent special grade) 62.7 g and zinc acetate dihydrate (commercial reagent special grade) 14.5 g were dissolved in ion-exchanged water, and 1200 ml of aqueous solution A1 was prepared with commercially available γ-alumina (particles). Suspended 6.7 g (diameter of about 80 μm), stirred for 30 minutes, 37.1 g of sodium carbonate (special grade of commercial reagent) was dissolved in ion-exchanged water, and 450 ml of aqueous solution B1 was added dropwise at room temperature while stirring. A precipitate formed. After washing the precipitate with ion-exchanged water, the obtained cake was pulverized, dried at 120 ° C. for 10 hours, and then baked at 360 ° C. for 4 hours to obtain 27 g of baked powder. The composition of the calcined powder is NiO / ZnO / Al ₂ O _Three = 61% by mass / 17% by mass / 22% by mass.
The obtained calcined powder was tableted and molded to give a particle size of 1.0 to 1.4 mm. Catalyst (1) 6 cm ^Three In a flow-type reaction tube having a diameter of 1.27 cm and reduced in a hydrogen stream at 350 ° C. for 3 hours, followed by a reaction temperature of 180 ° C. and LHSV = 0.5 h. ^-1 Then, a desulfurization test of JIS No. 1 kerosene (sulfur concentration: 49 mass ppm) was conducted in the absence of hydrogen, and the sulfur concentration of the produced kerosene after 200 hours is shown in Table 1.
[0038]
(Example 2)
Nickel nitrate hexahydrate (commercial reagent special grade) 98.5 g and zinc nitrate hexahydrate (commercial reagent special grade) 26.5 g were dissolved in ion-exchanged water to give 150 ml of aqueous solution A2, sodium carbonate (commercial reagent special grade). ) 47.7 g dissolved in ion-exchanged water to 400 ml, and dropwise added at 40 ° C. with stirring to an aqueous solution B2 in which 1.6 g of commercially available pseudo boehmite (particle size: about 50 μm) was suspended to form a precipitate. . After washing the precipitate with ion-exchanged water, the obtained cake was pulverized, dried at 120 ° C. for 10 hours, and baked at 360 ° C. for 4 hours to obtain 31 g of baked powder. The composition of the calcined powder is NiO / ZnO / Al ₂ O _Three = 75% by mass / 22% by mass / 3% by mass.
The obtained calcined powder was tableted and molded to a particle size of 1.0 to 1.4 mm. Catalyst (2) 6 cm ^Three In a flow-type reaction tube having a diameter of 1.27 cm and reduced in a hydrogen stream at 350 ° C. for 3 hours, followed by a reaction temperature of 180 ° C. and LHSV = 0.5 h. ^-1 Then, a desulfurization test of JIS No. 1 kerosene (sulfur concentration: 49 mass ppm) was conducted in the absence of hydrogen, and the sulfur concentration of the produced kerosene after 200 hours is shown in Table 1.
[0039]
(Comparative Example 1)
Nickel acetate tetrahydrate (commercial reagent special grade) 90.7 g and zinc acetate dihydrate (commercial reagent special grade) 14.8 g were dissolved in ion-exchanged water, and 1200 ml of aqueous solution A3 was prepared with commercially available γ-alumina (particles). Suspend 0.9 g (diameter of about 80 μm), stir for 30 min, dissolve 33.6 g of sodium carbonate (commercial reagent special grade) in ion-exchanged water, add 450 ml of aqueous solution B3 dropwise with stirring at room temperature, precipitate Formed. After washing the precipitate with ion-exchanged water, the obtained cake was pulverized, dried at 120 ° C. for 10 hours, and calcined at 360 ° C. for 4 hours to obtain 30 g of calcined powder. The composition of the calcined powder is NiO / ZnO / Al ₂ O _Three = 81% by mass / 16% by mass / 3% by mass.
The obtained calcined powder was compression-molded, and the catalyst size was adjusted to a particle size of 1.0 to 1.4 mm 6 cm ^Three In a flow-type reaction tube having a diameter of 1.27 cm and reduced in a hydrogen stream at 350 ° C. for 3 hours, followed by a reaction temperature of 180 ° C. and LHSV = 0.5 h. ^-1 Then, a desulfurization test of JIS No. 1 kerosene (sulfur concentration: 49 mass ppm) was conducted in the absence of hydrogen, and the sulfur concentration of the produced kerosene after 200 hours is shown in Table 1.
[0040]
(Comparative Example 2)
Nickel acetate tetrahydrate (commercial reagent special grade) 25.3 g and zinc acetate dihydrate (commercial reagent special grade) 44.3 g were dissolved in ion-exchanged water, and 1200 ml of aqueous solution A4 was added to commercially available γ-alumina (particles). Suspend 7.5 g (diameter of about 80 μm), and after stirring for 30 minutes, 23.6 g of sodium carbonate (commercial reagent special grade) is dissolved in ion-exchanged water, and 450 ml of aqueous solution B4 is added dropwise at room temperature while stirring. A precipitate formed. After washing the precipitate with ion-exchanged water, the obtained cake was pulverized, dried at 120 ° C. for 10 hours, and baked at 360 ° C. for 4 hours to obtain 28 g of baked powder. The composition of the calcined powder is NiO / ZnO / Al ₂ O _Three = 24% by mass / 52% by mass / 24% by mass.
The obtained calcined powder was tableted and molded to give a particle size of 1.0 to 1.4 mm. Catalyst (4) 6 cm ^Three In a flow-type reaction tube having a diameter of 1.27 cm and reduced in a hydrogen stream at 350 ° C. for 3 hours, followed by a reaction temperature of 180 ° C. and LHSV = 0.5 h. ^-1 Then, a desulfurization test of JIS No. 1 kerosene (sulfur concentration: 49 mass ppm) was conducted in the absence of hydrogen, and the sulfur concentration of the produced kerosene after 200 hours is shown in Table 1.
[0041]
(Comparative Example 3)
Nickel nitrate hexahydrate (commercial reagent special grade) 103.4 g and zinc nitrate hexahydrate (commercial reagent special grade) 27.8 g were dissolved in ion-exchanged water to make 150 ml of aqueous solution A5, sodium carbonate (commercial reagent special grade). ) 50.1 g was dissolved in ion-exchanged water and added dropwise at 40 ° C. to 400 ml of aqueous solution B5 with stirring to form a precipitate. After washing the precipitate with ion-exchanged water, the obtained cake was pulverized, dried at 120 ° C. for 10 hours, and baked at 360 ° C. for 4 hours to obtain 31 g of baked powder. The composition of the calcined powder is NiO / ZnO / Al ₂ O _Three = 78% by mass / 22% by mass / 0% by mass.
The obtained calcined powder was tableted and molded to a particle size of 1.0 to 1.4 mm (5) 6 cm ^Three In a flow-type reaction tube having a diameter of 1.27 cm and reduced in a hydrogen stream at 350 ° C. for 3 hours, followed by a reaction temperature of 180 ° C. and LHSV = 0.5 h. ^-1 Then, a desulfurization test of JIS No. 1 kerosene (sulfur concentration: 49 mass ppm) was conducted in the absence of hydrogen, and the sulfur concentration of the produced kerosene after 200 hours is shown in Table 1.
[0042]
[Table 1]

[0043]
(Example 3)
In the fuel cell system of FIG. 1, the desulfurizer 5 was filled with the catalyst (1) obtained in Example 1, and a power generation test was conducted using No. 1 kerosene (sulfur concentration: 23 mass ppm) as fuel. During the operation for 150 hours, the desulfurizer operated normally and no decrease in the activity of the catalyst was observed. Desulfurization conditions are as follows: temperature 180 ° C., normal pressure, no hydrogen flow, LHSV = 0.5h ^-1 Met.
At this time, Ru-based catalyst is used for steam reforming, S / C = 3, temperature 700 ° C., LHSV = 5 h ^-1 In the shift condition (reactor 10), a copper-zinc catalyst was used at 200 ° C., GHSV = 2000 h. ^-1 In the carbon monoxide selective oxidation step (reactor 11) under the conditions of ₂ / CO = 3, temperature 150 ° C., GHSV = 5000h ^-1 The operation was performed under the conditions. The fuel cell also operated normally and the electric load 15 was operated smoothly.
[Brief description of the drawings]
FIG. 1 is a schematic view showing an example of a fuel cell system of the present invention.
[Explanation of symbols]
1 Water tank
2 Water pump
3 Fuel tank
4 Fuel pump
5 Desulfurizer
6 Vaporizer
7 Reformer
8 Air blower
9 High temperature shift reactor
10 Low temperature shift reactor
11 Carbon monoxide selective oxidation reactor
12 Anode
13 Cathode
14 Solid polymer electrolyte
15 Electric load
16 Exhaust port
17 Polymer electrolyte fuel cell
18 Heating burner

Claims (4)

30 to 80% by mass of nickel oxide obtained by calcining a catalyst precursor formed by coprecipitation using at least one alumina selected from γ-alumina, β-alumina and pseudoboehmite as a core, and a component containing nickel and zinc A hydrocarbon desulfurization catalyst comprising 10 to 60 % by mass of zinc oxide and 0.1 to 40% by mass of alumina.   A hydrocarbon desulfurization method comprising desulfurizing a hydrocarbon containing a sulfur content to a sulfur concentration of 0.1 mass ppm or less using the catalyst according to claim 1. 3. The hydrocarbon desulfurization method according to claim 2, wherein the desulfurization is performed in the absence of hydrogen.   A desulfurization device having a reaction part filled with the catalyst according to claim 1 and desulfurizing hydrocarbons containing sulfur, and hydrocarbons desulfurized by the desulfurization device into hydrogen-based fuel gas A fuel cell system having at least a reforming device for reforming.

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