JP4267483B2 - Adsorbent for removing sulfur compounds and method for producing hydrogen for fuel cells - Google Patents

Description

  The present invention relates to an adsorbent for removing sulfur compounds, a method for producing hydrogen for fuel cells, and a fuel cell system. More specifically, in the present invention, the sulfur compound in the hydrocarbon fuel or the oxygen-containing hydrocarbon fuel is desulfurized by using the above-mentioned adsorbent, an adsorbent for removing sulfur compounds that can efficiently remove even a low concentration even at room temperature. The present invention relates to a method for effectively producing hydrogen for a fuel cell from a hydrocarbon fuel or an oxygen-containing hydrocarbon fuel, and a fuel cell system using hydrogen obtained by the method.

In recent years, new energy technology has attracted attention due to environmental problems, and fuel cells are attracting attention as one of the new energy technologies. This fuel cell converts chemical energy into electrical energy by electrochemically reacting hydrogen and oxygen, and has a feature of high energy use efficiency. Alternatively, research into practical use is actively conducted for automobiles and the like.
For this fuel cell, types such as a phosphoric acid type, a molten carbonate type, a solid oxide type, and a solid polymer type are known depending on the type of electrolyte used. On the other hand, as a hydrogen source, liquefied natural gas mainly composed of methanol and methane, city gas mainly composed of natural gas, synthetic liquid fuel using natural gas as a raw material, and petroleum-based systems such as LPG, naphtha and kerosene The use of hydrocarbons has been studied.

When producing hydrogen using these gaseous or liquid hydrocarbons, generally, there is a method of treating the hydrocarbons by partial oxidation reforming, autothermal reforming or steam reforming in the presence of a reforming catalyst. It is used.
When reforming hydrocarbon fuels such as LPG, city gas, and kerosene to produce hydrogen for fuel, the sulfur content in the fuel is reduced to 0.1 ppm or less in order to suppress poisoning of the reforming catalyst. Is required. Further, when propylene, butene, etc. are used as a raw material for petrochemical products, the sulfur content is required to be reduced to 0.1 ppm or less in order to prevent poisoning of the catalyst.
In the LPG, as a sulfur compound, dimethyl sulfide (DMS), t-butyl mercaptan (TBM), methyl ethyl sulfide, etc. added as an odorant in addition to methyl mercaptan and carbonyl sulfide (COS) are generally included. include. Recently, a plan to use an oxygen-containing hydrocarbon compound such as dimethyl ether as a fuel has been advanced. Although this oxygen-containing hydrocarbon itself does not contain a sulfur compound, the addition of the above odorant has been studied intentionally in order to prevent leakage.

Various adsorbents that adsorb and remove sulfur compounds in hydrocarbon fuels such as LPG and city gas are known. However, some of these adsorbents exhibit high desulfurization performance at about 150 to 300 ° C., but the actual condition is that the desulfurization performance at room temperature is not always satisfactory.
For example, a desulfurization agent (for example, refer to Patent Document 1) in which Ag, Cu, Zn, Fe, Co, Ni, etc. are supported on a hydrophobic zeolite by ion exchange, or Ag or Cu is added to Y-type zeolite, β-type zeolite, or X-type zeolite. A desulfurization agent supporting Cu (for example, see Patent Document 2) is disclosed. However, although these desulfurization agents can efficiently adsorb and remove mercaptans and sulfides at room temperature, they hardly adsorb carbonyl sulfide.
Further, a copper-zinc desulfurization agent is disclosed (for example, see Patent Document 3). In this desulfurization agent, various sulfur compounds can be adsorbed and removed at a temperature of 150 ° C. or higher, but a low temperature of 100 ° C. or lower. Then, the adsorption | suction performance with respect to a sulfur compound is low. Furthermore, a desulfurization agent in which copper is supported on a porous carrier such as alumina is disclosed (for example, see Patent Document 4). Although this desulfurizing agent can be used even at a temperature of 100 ° C. or lower, its adsorption performance is not fully satisfactory.

JP 2001-286753 A JP 2001-305123 A Japanese Patent Laid-Open No. 2-302496 (page 2) JP 2001-123188 A (page 3)

  Under such circumstances, the present invention provides an adsorbent for removing sulfur compounds, which can efficiently remove various sulfur compounds in hydrocarbon fuels or oxygen-containing hydrocarbon fuels to a low concentration even at room temperature. It is an object of the present invention to provide a method for effectively producing hydrogen for a fuel cell from a hydrocarbon fuel or an oxygen-containing hydrocarbon fuel that has been desulfurized using the same, and a fuel cell system using hydrogen obtained by the method. is there.

As a result of intensive research to achieve the above object, the present inventors have found that cerium oxide, particularly those having an average crystallite size of 10 nm or less, have an excellent ability to adsorb various sulfur compounds even at room temperature. And, it has been found that hydrogen for fuel cells can be obtained effectively by reforming hydrocarbon fuel or oxygen-containing hydrocarbon fuel desulfurized using this adsorbent. The present invention has been completed based on such findings.
That is, this invention is following (1)-(18).
(1) An adsorbent containing 50% by mass or more of cerium oxide having a hydrogen consumption of 200 μmol / g or more at a temperature of 600 ° C. or less in a temperature reduction test, based on the total amount of the adsorbent, and not containing silver and its oxide Removing at least one sulfur compound selected from carbonyl sulfide, dimethyl disulfide, dimethyl sulfide and t-butyl mercaptan in a hydrocarbon fuel or an oxygen-containing hydrocarbon fuel at a temperature of -50 to 150 ° C. A method for removing sulfur compounds.
(2) The method for removing a sulfur compound according to the above (1) , using an adsorbent having a specific surface area of 20 m ² / g or more .
(3) The method for removing a sulfur compound according to the above (1) or (2), wherein the average crystallite diameter of cerium oxide is 10 nm or less .
(4) Ce-Si complex oxide, Ce-Zr complex oxide, Ce-Si-Zr complex oxide, Ce-Nb complex oxide, Ce-Bi complex oxide, Ce-Sb complex The removal method of the sulfur compound in any one of said (1)-(3) using the adsorption agent containing 1 type of complex oxide chosen from an oxide and Ce-Sn type complex oxide.
(5) The above (1) to (3) using an adsorbent in which at least one active metal species selected from Cu, Mn, Fe, Co, Ni, Au, Pb and Sb is supported on cerium oxide. ). The method for removing a sulfur compound according to any one of the above.
(6) The description of (4) above, wherein the composite oxide uses an adsorbent in which at least one active metal species selected from Cu, Mn, Fe, Co, Ni, Au, Pb and Sb is supported. A method for removing sulfur compounds.
(7) The method for removing a sulfur compound according to (5) or (6) above, using an adsorbent obtained by baking at a temperature of 400 ° C. or lower.
(8) The method for removing a sulfur compound according to the above (5) or (6), wherein the supported amount of the active metal species is 1 to 50% by mass based on the total amount of the adsorbent as an element.
(9) The method for removing a sulfur compound according to the above (5) or (6), wherein the supported amount of the active metal species is 1 to 5% by mass based on the total amount of the adsorbent as an element.

(10) The hydrocarbon fuel is at least one hydrocarbon compound or oxygen selected from LPG, city gas, natural gas, naphtha, kerosene, light oil or ethane, ethylene, propane, propylene, butane, butene, methanol, and dimethyl ether The removal method of the sulfur compound in any one of said (1)-(9) which is a containing hydrocarbon compound.
(11) The method for removing a sulfur compound according to any one of the above (1) to (10), wherein the sulfur compound is carbonyl sulfide.
(12) The method for removing a sulfur compound according to the above (11), using an adsorbent having a specific surface area of 100 m ² / g or more.
(13) The method for removing a sulfur compound according to the above (11) or (12), using an adsorbent containing cerium oxide calcined at a temperature of 300 to 600 ° C.

(14) The method for removing a sulfur compound according to any one of (1) to (13), wherein the adsorbent is used under a condition in which hydrogen or oxygen is not added.
(15) A desulfurization means using an adsorbent for removing sulfur compounds having a sulfur adsorption capacity different from the adsorbent used in any one of the above (1) to (13) is provided upstream or downstream of the desulfurization means. The method for removing a sulfur compound according to any one of (1) to (14) above.
(16) After the sulfur compound in the hydrocarbon fuel or the oxygen-containing hydrocarbon fuel is desulfurized by the sulfur compound removal method according to any one of (1) to (15) above, the obtained desulfurized fuel is used. A method for producing hydrogen for a fuel cell, comprising contacting with a partial oxidation reforming catalyst, an autothermal reforming catalyst or a steam reforming catalyst.
(17) The method for producing hydrogen for a fuel cell according to the above (16), wherein the partial oxidation reforming catalyst, autothermal reforming catalyst or steam reforming catalyst is a ruthenium-based or nickel-based catalyst.
(18) A fuel cell system including a hydrogen production system for carrying out the production method according to (16) or (17).

  According to the present invention, sulfur compounds in hydrocarbon fuels or oxygen-containing hydrocarbon fuels, particularly sulfur compounds that can be efficiently removed to a low concentration even at room temperature can be efficiently removed at room temperature with other adsorbents. Provided are an adsorbent, a method for effectively producing hydrogen for a fuel cell from a hydrocarbon fuel or an oxygen-containing hydrocarbon fuel desulfurized using the adsorbent, and a fuel cell system using hydrogen obtained by this method can do.

The adsorbent for removing sulfur compounds of the present invention contains cerium oxide and is used for removing sulfur compounds in hydrocarbon fuels or oxygen-containing hydrocarbon fuels.
There is no restriction | limiting in particular about the form of the cerium oxide contained in the adsorbent of this invention, For example, the adsorbent of the following form can be mentioned.
(B) An adsorbent containing a composite oxide containing cerium oxide and an element other than cerium (hereinafter referred to as Ce-M composite oxide) alone.
( B ) An adsorbent comprising a carrier made of cerium oxide or a Ce-M composite oxide and carrying an active metal species.
( C ) An adsorbent containing an active metal species supported on a carrier made of cerium oxide or Ce-M composite oxide and another metal oxide.
( D ) An adsorbent containing a refractory porous carrier carrying cerium oxide or Ce-M composite oxide.
( E ) An adsorbent containing a refractory porous carrier supporting cerium oxide or Ce-M composite oxide and further supporting an active metal species.

Examples of elements other than cerium constituting the Ce-M composite oxide include at least one metal element selected from elements belonging to Groups 2 to 16 of the periodic table. Among such Ce-M complex oxides, Ce-Si complex oxides, Ce-Zr complex oxides, Ce-Si-Zr complex oxides, Ce-Ti complex oxides, Ce-Nb Of these, a complex oxide, a Ce—Bi complex oxide, a Ce—Sb complex oxide, and the like are particularly preferable.
In (b) and (d), examples of other metal oxides used in combination with cerium oxide or Ce-M composite oxide include, for example, La, Sc, Y, Nd, Pr, Sm, Gd, and Yb. Preferred examples include oxides of selected metals. One kind of these metal oxides may be used, or two or more kinds may be used in combination.

In the above (c) and (d), the active metal species supported on the carrier is an element selected from elements belonging to Groups 1 to 15 of the periodic table, such as Cs, Ba, Yb, Ti, Zr, and Hf. Nb, Mo, W, Mn, Re, Fe, Ru, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Ga, In, Sn, Bi, or the like can be used. These may be supported alone or in combination of two or more. When these elements are added, the desulfurization performance of cerium oxide is improved.
Desulfurization performance of the adsorbent obtained by supporting such an active metal species on a carrier made of cerium oxide or Ce-M composite oxide, or cerium oxide or Ce-M composite oxide and other metal oxides Can be improved.
The amount of the active metal species supported is not particularly limited, but is usually selected in the range of 1 to 50% by mass, preferably 3 to 30% by mass, based on the total amount of the active metal species with the carrier.
In particular, in the removal of carbonyl sulfide, 1 to 10% by mass, particularly 5% by mass or less is preferable.

In the above (e) and (f), as the refractory porous carrier, for example, at least one selected from silica, alumina, silica-alumina, titania, zirconia, zeolite, magnesia, diatomaceous earth, clay, clay and the like is used. be able to.
Adsorbents obtained by supporting cerium oxide or Ce-M composite oxide on these refractory porous carriers can also be preferably used.
In the adsorbent of the present invention, the content of cerium oxide is preferably 10% by mass or more, and more preferably 50% by mass or more from the viewpoint of desulfurization performance. Most preferably, it is 80 mass% or more.
Further, the cerium oxide in the adsorbent preferably has an average crystallite diameter of 10 nm or less, preferably 1 to 10 nm, from the viewpoint of desulfurization performance. The average crystallite size of the cerium oxide can be controlled when preparing the adsorbent.

The average crystallite diameter of cerium oxide in the adsorbent here is a particle diameter measured with a transmission electron microscope. The particles do not necessarily need to be crystals, and refer to the particle diameter of primary particles regardless of crystal or amorphous. As used herein, primary particles refer to particles that have not been aggregated or particles that have not been aggregated. Even when the particles are aggregated to form secondary particles, tertiary particles, or the like, the average crystallite size of cerium oxide refers to the particle size of the primary particles. If the observed particle size is uneven, 10 or more primary particles are arbitrarily selected, the average value of the particle diameters is obtained, this is the average crystallite diameter, and the particle shape is rod-shaped or needle-shaped. In some cases, the particle size is not the particle length but the width. However, when cerium oxide is supported on a carrier such as alumina, the average crystallite diameter of CeO ₂ indicates the primary particle diameter of the supported cerium oxide and forms a solid solution with other oxides. In this case, the primary particle diameter of the solid solution particles containing cerium shall be indicated. In the measurement using the transmission electron microscope as described above, when the boundary of the particles is clearly observed, it can be measured using an automatic counter or the like.

Further, the cerium oxide preferably has a hydrogen consumption of 200 μmol / g or more at a temperature of 600 ° C. or less in a temperature-programmed reduction (TPR) test from the viewpoint of desulfurization performance, and is 300 μmol / g or more. Those are more preferred. In this temperature reduction test of cerium oxide, 100 mg of a sample was used, argon gas containing 10% by volume of hydrogen was introduced at 20 ml / min, and the temperature was raised to 827 ° C. at a rate of 10 ° C./min. The hydrogen consumption at a temperature of 600 ° C. or lower is obtained.
In the TPR measurement of cerium oxide, peaks due to reduction (H ₂ consumption) are observed on the low temperature side of about 300 to 550 ° C. and on the high temperature side of 827 ° C. or higher. When cerium oxide is reduced with hydrogen, CeO ₂ changes to Ce ₂ O ₃ as shown in the following formula.
2CeO ₂ + H ₂ → Ce ₂ O ₃ + H ₂ O
Regarding the two peaks obtained by the TPR test, it is considered that the low-temperature side peak is due to reduction of the CeO ₂ surface on the particle surface, and the high-temperature side peak is due to reduction of bulk CeO ₂ . In the study by the present inventors, it has been found that cerium oxide having a large peak (hydrogen consumption) on the low temperature side is superior in desulfurization performance at room temperature. The reason for this is not necessarily clear, but oxygen of cerium oxide that reacts (reduces) with H ₂ at a temperature of about 300 to 550 ° C. reacts with sulfur compounds at room temperature to chemisorb sulfur compounds. It is estimated that

The adsorbent of the present invention has a specific surface area of preferably 20 m ² / g or more, more preferably 50 m ² / g or more, from the viewpoint of desulfurization performance. In addition, the specific surface area of an adsorbent can be performed as follows, for example using the Yuasa Ionics company specific surface area measuring apparatus.
That is, about 100 mg of a sample was filled in a sample tube, and heat-dehydrated in a nitrogen stream at 200 ° C. for 20 minutes as a pretreatment. Next, nitrogen (30%) / helium (70%) mixed gas was circulated at the liquid nitrogen temperature to adsorb nitrogen, and then desorbed and the specific surface area was determined from the amount of nitrogen adsorbed measured by a TCD detector.
The sulfur compound-removing adsorbent containing cerium oxide and adsorbing carbonyl sulfide preferably has a specific surface area of 100 m ² / g or more, particularly preferably 150 m ² / g or more.

In the production of the adsorbent of the present invention, for example, when producing cerium oxide alone, an aqueous solution containing a cerium source, specifically a cerium nitrate, and the like are brought into contact with an alkaline aqueous solution to form a precipitate, Next, the precipitate is collected by filtration, washed with water, dried at a temperature of about 50 to 200 ° C., fired at a temperature of about 300 to 600 ° C., and then molded by tableting or the like to further obtain a desired particle size. It can be crushed.
Moreover, in order to carry | support cerium oxide on a refractory porous support | carrier, a conventionally well-known method, for example, a pore filling method, a dipping method, an evaporation to dryness method etc., can be used. Under the present circumstances, drying temperature is about 50-200 degreeC normally, and a calcination temperature is about 250-500 degreeC normally.
Although the prepared catalyst can be used without reduction, it is preferable to perform a reduction treatment in terms of catalytic activity. For this reduction treatment, a reduction method in which treatment is performed in an air stream containing hydrogen or CO is used. Usually, it is preferable to carry out at a temperature of 300 to 600 ° C. for 1 to 24 hours, preferably 3 to 12 hours under an air stream containing hydrogen.

Furthermore, in order to support the above-mentioned active metal species on a carrier made of cerium oxide or the like, a conventionally known method such as a pore filling method, a dipping method, an evaporation to dryness method or the like can be employed as described above. At this time, the drying temperature is usually about 50 to 200 ° C., and the firing temperature is preferably 400 ° C. or less, and more preferably in the range of 100 to 400 ° C.
The adsorbent for removing sulfur compounds of the present invention thus obtained is applied to hydrocarbon fuel or oxygen-containing hydrocarbon fuel. Here, examples of the hydrocarbon fuel include LPG, city gas, natural gas, naphtha, kerosene, light oil, or at least one hydrocarbon compound selected from ethane, ethylene, propane, propylene, butane, and butene. Can do. Examples of the oxygen-containing hydrocarbon fuel include at least one selected from alcohols such as methanol, ethanol and isopropanol, and ethers such as dimethyl ether and methyl ethyl ether. Among these, dimethyl ether is particularly preferable.
The concentration of the sulfur compound in the hydrocarbon or oxygen-containing hydrocarbon-containing gas to which the adsorbent of the present invention is applied is preferably 0.001 to 10,000 ppm by volume, particularly preferably 0.1 to 100 ppm by volume. As desulfurization conditions, the normal temperature is selected in the range of −50 to 150 ° C., and the GHSV (gas hourly space velocity) is selected in the range of 100 to 1,000,000 h ⁻¹ .

When the desulfurization temperature exceeds 150 ° C., the adsorption of sulfur compounds is difficult to occur. A preferred temperature is in the range of −50 to 120 ° C., more preferably −20 to 100 ° C. Also preferred GHSV is 100～100,000H ^-1, more preferably from 100~50,000h ^-1.
Next, in the method for producing hydrogen for a fuel cell according to the present invention, after the sulfur compound in the hydrocarbon fuel or the oxygen-containing hydrocarbon fuel is desulfurized using the adsorbent according to the present invention, the desulfurized fuel is obtained. To produce hydrogen.
In the present invention, when the sulfur compound in the hydrocarbon fuel or the oxygen-containing hydrocarbon fuel is desulfurized using the adsorbent of the present invention, the desulfurization means using the adsorbent for removing sulfur compounds of the present invention is used. A desulfurization means using a sulfur compound removing adsorbent having a different sulfur adsorbing ability from that of the adsorbent may be separately provided on the upstream side or the downstream side. Examples of the desulfurizing agent include those in which a silver component, a copper component, a zinc component, an iron component, a nickel component and the like are supported on zeolite. In this way, by removing mercaptans, sulfides, etc. using desulfurizing agents having different sulfur adsorption capacities, and removing carbonyl sulfide using the sulfur compound removing adsorbent of the present invention, sulfur compounds can be efficiently removed. Can do.
As the reforming method, methods such as partial oxidation reforming, autothermal reforming, and steam reforming can be used. In this reforming method, the sulfur compound concentration in the desulfurized hydrocarbon fuel or oxygen-containing hydrocarbon fuel is preferably 0.1 ppm by volume or less, particularly 0.05 volume, from the viewpoint of the life of each reforming catalyst. ppm or less is preferable.

The partial oxidation reforming is a method for producing hydrogen by a partial oxidation reaction of hydrocarbons, and in the presence of a partial oxidation reforming catalyst, usually a reaction pressure of normal pressure to 5 MPa, a reaction temperature of 400 to 1,100 ° C. The reforming reaction is carried out under the conditions of GHSV 1,000 to 100,000 h ⁻¹ and oxygen (O ₂ ) / carbon ratio 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, and the reaction temperature is from 400 to 1,100. The reforming reaction is carried out under the conditions of ° C., oxygen (O ₂ ) / carbon ratio of 0.1 to 1, steam / carbon ratio of 0.1 to 10, and GHSV of 1,000 to 100,000 h ⁻¹ .
Furthermore, steam reforming is a method for producing hydrogen by bringing steam into contact with a hydrocarbon, usually in the presence of a steam reforming catalyst, at a reaction pressure of normal pressure to 3 MPa, a reaction temperature of 200 to 900 ° C., steam. The reforming reaction is performed under the conditions of / carbon ratio of 1.5 to 10 and GHSV of 1,000 to 100,000 h ⁻¹ .

In the present invention, the partial oxidation reforming catalyst, autothermal reforming catalyst, and steam reforming catalyst can be appropriately selected from conventionally known catalysts, but are particularly ruthenium-based and nickel-based. A catalyst is 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 present invention also provides a fuel cell system using hydrogen obtained by the production method. The fuel cell system of the present invention will be described below with reference to FIG.
FIG. 1 is a schematic flowchart showing an example of the fuel cell system of the present invention. According to FIG. 1, the fuel in the fuel tank 21 is decompressed by the regulator 22 as necessary and flows into the desulfurizer 23. The desulfurizer can be filled with the adsorbent of the present invention. The fuel desulfurized by the desulfurizer 23 is mixed with water from the water tank via the water pump 24 to vaporize the water and sent to the reformer 31.
The reformer 31 is filled with the above-described reforming catalyst, and from the fuel mixture (mixed gas containing water vapor, oxygen and hydrocarbon fuel or oxygen-containing hydrocarbon fuel) fed into the reformer 31, Hydrogen or synthesis gas is produced by any of the reforming reactions described above.

The hydrogen or synthesis gas thus produced is reduced through the CO converter 32 and the CO selective oxidizer 33 to such an extent that the CO concentration does not affect the characteristics of the fuel cell. Examples of the catalyst used in these reactors include an iron-chromium catalyst, a copper-zinc catalyst or a noble metal catalyst in the CO converter 32, and a ruthenium catalyst, a platinum catalyst or a noble metal catalyst in the CO selective oxidation furnace 33. The mixture etc. can be mentioned.
The fuel cell 34 is a solid polymer fuel cell having 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 as 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. . Platinum black, activated carbon-supported Pt catalyst or Pt-Ru alloy catalyst is used for the negative electrode, and platinum black, Pt catalyst supported on activated carbon 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. Further, in the steam separator 36 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 the water is used to generate water vapor. Can be used.
In the fuel cell 34, since heat is generated 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 includes a heat exchanger 37A that takes away heat generated during the reaction, a heat exchanger 37B for exchanging heat taken by the heat exchanger 37A with water, a cooler 37C, A pump 37D that circulates the refrigerant to the exchangers 37A and 37B and the cooler 37C is provided, and the hot water obtained in the heat exchanger 37B can be effectively used in other facilities.

EXAMPLES Next, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples.
In addition, the average crystallite diameter of cerium oxide in the obtained desulfurizing agent, H ₂ consumption (600 ° C. or less) by the TPR test, and the specific surface area of the desulfurizing agent were measured according to the method described in the specification.
Example 1
Mixing a solution prepared by dissolving 470 g of cerium nitrate hexahydrate (reagent special grade, manufactured by Wako Pure Chemical Industries, Ltd.) in 1 L of ion-exchanged water heated to 50 ° C. and a 3 mol / L NaOH aqueous solution The mixture was added dropwise so that the pH of the solution was maintained at 13, and the mixture was stirred for 1 hour while maintaining the temperature at 50 ° C.
Next, the produced solid matter was collected by filtration, washed with 20 L of ion-exchanged water, dried in a 110 ° C. blower dryer for 12 hours, and further calcined at 350 ° C. for 3 hours. Thereafter, tableting molding and pulverization were performed to obtain a sulfur compound removing adsorbent (hereinafter referred to as a desulfurization agent) made of CeO ₂ (A) having an average particle diameter of 0.8 mm. Table 1 shows the properties of this desulfurizing agent.

Example 2
A mixed solution of cerium nitrate hexahydrate (reagent special grade, manufactured by Wako Pure Chemical Industries, Ltd.) 470 g dissolved in 1 liter of ion-exchanged water heated to 50 ° C. and 30% by mass ammonia water The mixture was added dropwise so as to maintain a pH of 12, and the mixture was stirred for 1 hour while maintaining at 50 ° C.
Next, the produced solid matter was collected by filtration, washed with 20 L of ion-exchanged water, dried in a 110 ° C. blower dryer for 12 hours, and further calcined at 350 ° C. for 3 hours. Thereafter, tableting molding, by grinding, to obtain a desulfurizing agent comprising an average particle size 0.8mm of CeO ₂ (B). Table 1 shows the properties of this desulfurizing agent.

Example 3
Cerium nitrate hexahydrate [reagent special grade, manufactured by Wako Pure Chemical Industries, Ltd.] 605 g and zirconyl nitrate dihydrate [reagent special grade, manufactured by Wako Pure Chemical Industries, Ltd.] 52.0 g heated to 50 ° C. Preparation liquid A was obtained by dissolving in 1 L of exchange water. Separately, a 3N NaOH solution was prepared as Preparation Solution B. Preparation liquid A and preparation liquid B were dropped and mixed while maintaining the pH of the mixed liquid at 13.9, and then stirred for 1 hour while maintaining the mixed liquid at 50 ° C.
Next, the solid produced with ion-exchanged water was washed and filtered, then dried with an air dryer at 110 ° C. for 12 hours, and further fired at 400 ° C. for 3 hours. Thereafter, the product is tableted and pulverized to obtain a composite oxide [CeO ₂ (50) -ZrO ₂ (50)] of CeO ₂ and ZrO ₂ having an average particle diameter of 0.8 mm and a mass ratio of 50:50. A desulfurizing agent consisting of Table 1 shows the properties of this desulfurizing agent.

Example 4
Cerium nitrate hexahydrate [reagent special grade, manufactured by Wako Pure Chemical Industries, Ltd.] 310 g was dissolved in 60 mL of ion-exchanged water heated to 50 ° C. The solution was impregnated with 400 g of alumina (KHD-24), dried at 110 ° C. for 12 hours in a blow dryer, and further calcined at 400 ° C. for 3 hours. Thereafter, the product is tableted and pulverized to obtain CeO ₂ (20) / Al ₂ O ₃ (20 parts by weight of CeO ₂ supported on 80 parts by weight of an Al ₂ O ₃ carrier having an average particle diameter of 0.8 mm. 80) was obtained. Table 1 shows the properties of this desulfurizing agent.

Comparative Example 1
CeO ₂ (B) obtained in Example 2 was placed in a muffle furnace and baked at 800 ° C. for 6 hours to obtain a desulfurization agent made of CeO ₂ (C). Table 1 shows the properties of this desulfurizing agent.

Comparative Examples 2-6
Commercially available MnO ₂ , ZnO, alumina, β-type zeolite and activated carbon were used as the desulfurization agents of Comparative Examples 2 to 6, respectively. The specific surface areas of these desulfurizing agents are shown in Table 1.

Test example 1
Each desulfurization agent obtained in Examples 1 to 4 and Comparative Examples 1 to 6 was molded to 0.5 to 1 mm, and 1 cm ³ of the desulfurization agent was filled in a desulfurization tube having an inner diameter of 9 mm. The desulfurizing agent temperature was 20 ° C. at normal pressure, and propane gas containing 10 volppm (total 40 volppm) of COS, dimethyl sulfide (DMS), t-butyl mercaptan (TBM) and dimethyl disulfide (DMDS) was used at normal pressure, GHSV ( Gas hourly space velocity) was 30,000 h ⁻¹ .
Each sulfur compound concentration in the desulfurization pipe outlet gas was measured every hour by SCD (chemiluminescence sulfur detector) gas chromatography. Table 2 shows the time when the sulfur compound concentration exceeds 0.1 volppm and the total sulfur adsorption amount.

第１表、第２表から分かるように、比較例の多孔質体からなる脱硫剤は、脱硫性能がほとんど発揮されないが、酸化セリウムを含む実施例の脱硫剤は、顕著な脱硫性能を示した。

As can be seen from Tables 1 and 2, the desulfurization agent composed of the porous body of the comparative example shows almost no desulfurization performance, but the desulfurization agent of the example containing cerium oxide showed remarkable desulfurization performance. .

Examples 5 to 9, Reference Example 1
After impregnating the cerium oxide (A) with a metal salt shown in Table 3, drying at 120 ° C., firing is performed at 400 ° C., and 10% by mass of the metal species shown in Table 3 is supported based on the total amount. To obtain a desulfurizing agent.

Comparative Example 7
A desulfurization agent obtained by supporting 10% by mass of Ag on the total amount of β-type zeolite was obtained.
Test example 2
Each desulfurization agent of Examples 5 to 9, Comparative Example 7 and Reference Example 1 was molded to 0.5 to 1 mm, and 1 cm ³ of the desulfurization agent was filled in a desulfurization tube having an inner diameter of 9 mm. Propane gas containing COS 40 volppm was circulated under conditions of normal pressure and GHSV 30,000 h ^{−1 at} a normal pressure and a desulfurizing agent temperature of 20 ° C.
The COS concentration of the desulfurization pipe outlet gas was measured every hour by SCD (chemiluminescence sulfur detector) gas chromatography. Table 3 shows the time when the COS concentration exceeded 0.1 vol ppm.

第３表から分かるように、硫化カルボニルの除去には、Ｎｉ／ＣｅＯ₂及びＭｎ／ＣｅＯ₂が特に優れている。
参考例２〜６
酸化セリウム（Ａ）に硝酸銀溶液を用いて全量に基づきＡｇを１０質量％含浸担持させ、１２０℃で乾燥（焼成）したのち、さらに第４表に示す温度で焼成処理して、脱硫剤を得た。

As can be seen from Table 3, Ni / CeO ₂ and Mn / CeO ₂ are particularly excellent for removing carbonyl sulfide.
Reference Examples 2-6
A silver nitrate solution is used to impregnate and support 10% by mass of Ag in cerium oxide (A), dried (fired) at 120 ° C., and then fired at the temperature shown in Table 4 to obtain a desulfurizing agent. It was.

Test example 3
The desulfurization agents of Reference Examples 2 to 6 were molded to 0.5 to 1 mm, and 1 cm ³ of the desulfurization agent was filled in a desulfurization pipe having an inner diameter of 9 mm. Propane gas containing dimethyl sulfide (DMS) 40 volppm was circulated under normal pressure and GHSV 30,000 h ^-1 conditions at a normal pressure and a desulfurizing agent temperature of 20 ° C.
The dimethyl sulfide concentration in the desulfurization pipe outlet gas was measured every hour by SCD (chemiluminescence sulfur detector) gas chromatography. Table 4 shows the time when the dimethyl sulfide concentration exceeds 0.1 volppm.

第４表から、１２０〜５００℃の焼成温度範囲では、焼成温度が低いほど、ジメチルサルファイドが０．１volｐｐｍを超える時間が長くなり、吸着量が増大していることが分かる。

From Table 4, it can be seen that in the firing temperature range of 120 to 500 ° C., the lower the firing temperature, the longer the time for which dimethyl sulfide exceeds 0.1 volppm, and the amount of adsorption increases.

Reference Examples 7-10
Similar to Example 1, a compound oxide of CeO ₂ and other elements was prepared by adding a compound of an element other than cerium together with cerium nitrate. Propane gas containing 10 volppm (total 40 volppm) of carbonyl sulfide, dimethyl sulfide, t-butyl mercaptan, and dimethyl disulfide was circulated at normal pressure and GHSV = 30000 h ⁻¹ . The sulfur compound concentration in the desulfurization pipe outlet gas was measured every hour by SCD (chemiluminescence sulfur detector) gas chromatography method. The results are shown in Table 5.
The sulfur compound concentration in the desulfurization pipe outlet gas is measured every hour by SCD (chemiluminescence sulfur detector) gas chromatography method, and the time when the sulfur compound concentration exceeds 0.1 ppm is shown in Table 5 as the breakthrough time. Indicated.

Examples 10-13
Cerium oxide (A) was impregnated with various metal salts, dried at 120 ° C., and then fired at 400 ° C. to obtain a desulfurization agent described in Table 6 below. Propane gas containing 40 volppm of carbonyl sulfide (COS) was passed through these desulfurizing agents at normal pressure and GHSV = 30000 h ⁻¹ . The sulfur compound concentration in the desulfurization pipe outlet gas was measured every hour by SCD (chemiluminescence sulfur detector) gas chromatography method, and Table 6 shows the breakthrough time when the carbonyl sulfide concentration exceeds 0.1 ppm. It was.

Examples 14 to 15 and Comparative Example 8
The performance test was performed as follows for the cerium oxide of Example 1 and the cerium oxide CeO ₂ (HS) and CeO ₂ (HS2) manufactured by Daiichi Rare Element Industries having a high surface area.
A desulfurizing agent was molded to 0.5 to 1 mm, and 1 cc of the desulfurizing agent was filled in a desulfurizing tube having an inner diameter of 9 mm. Propane gas containing 40 volppm of carbonyl sulfide (COS) was circulated at GHSV = 30000 h ⁻¹ at normal pressure and a desulfurizing agent temperature of 20 ° C. The sulfur compound concentration in the desulfurization pipe outlet gas was measured every hour by SCD (chemiluminescence sulfur detector) gas chromatography method. Table 7 shows the breakthrough time when the COS concentration exceeded 0.1 ppm.

Example 16
The cerium oxide CeO ₂ (A) of Example 1 was dried at 150 ° C. and then calcinated at different calcination temperatures. These desulfurizing agents were evaluated in the same manner as in Example 24. As shown in Table 8, the COS breakthrough time was improved for those fired at 300 ° C. to 600 ° C. as compared with the dried product.

Examples 17-20, Reference Examples 11-12
About the cerium oxide of Example 1 , as shown in Table 9, the thing with different metal seed | species and a load was prepared. Propane gas containing 40 volppm of carbonyl sulfide (COS) was circulated at normal pressure and GHSV = 60000 h ⁻¹ . The sulfur compound concentration in the desulfurization pipe outlet gas was measured every hour by SCD (chemiluminescence sulfur detector) gas chromatography method. Table 9 shows the breakthrough time when the COS concentration exceeded 0.1 ppm.

Examples 21-26
As in Example 1, a compound oxide of CeO ₂ and other elements was prepared by adding a compound of an element other than cerium together with cerium nitrate. Propane gas containing 40 volppm of carbonyl sulfide (COS) was passed through these desulfurizing agents at normal pressure and GHSV = 30000 h ⁻¹ . The sulfur compound concentration in the desulfurization pipe outlet gas was measured every hour by SCD (chemiluminescence sulfur detector) gas chromatography method, and Table 10 shows the breakthrough time when the COS concentration exceeded 0.1 ppm.
The results are shown in Table 10.

Schematic flowchart showing an example of the fuel cell system of the present invention

Explanation of symbols

1: Fuel cell system 11: Water supply pipe 12: Fuel introduction pipe 20: Hydrogen production system 21: Fuel tank 22: Regulator 23: Desulfurizer 31: Reformer 31A: Boiler 32: CO converter 33: CO selective oxidizer 34: Fuel cell 34A: Negative electrode 34B: Positive electrode 34C: Polymer electrolyte 36: Steam separator 37: Waste heat recovery device 37A: Heat exchanger 37B: Heat exchanger 37C: Cooler

Claims (18)

Using an adsorbent containing 50% by mass or more of cerium oxide having a hydrogen consumption of 200 μmol / g or more at a temperature of 600 ° C. or less in a temperature reduction test, based on the total amount of the adsorbent, and not containing silver and oxides thereof. Removing at least one sulfur compound selected from carbonyl sulfide, dimethyl disulfide, dimethyl sulfide and t-butyl mercaptan in a hydrocarbon fuel or an oxygen-containing hydrocarbon fuel at a temperature of -50 to 150 ° C. Removal method. The method for removing a sulfur compound according to claim 1, wherein an adsorbent having a specific surface area of 20 m ² / g or more is used . The method for removing a sulfur compound according to claim 1 or 2, wherein the average crystallite diameter of cerium oxide is 10 nm or less . Ce-Si complex oxide, Ce-Zr complex oxide, Ce-Si-Zr complex oxide, Ce-Nb complex oxide, Ce-Bi complex oxide, Ce-Sb complex oxide, The removal method of the sulfur compound of any one of Claims 1-3 using the adsorption agent containing 1 type of complex oxide chosen from Ce-Sn type complex oxide. The cerium oxide uses an adsorbent in which at least one active metal species selected from Cu, Mn, Fe, Co, Ni, Au, Pb and Sb is supported. The sulfur compound removal method as described. The removal of the sulfur compound according to claim 4, wherein the composite oxide is an adsorbent in which at least one active metal species selected from Cu, Mn, Fe, Co, Ni, Au, Pb and Sb is supported. Method. The method for removing a sulfur compound according to claim 5 or 6, wherein an adsorbent obtained by baking at a temperature of 400 ° C or lower is used. The method for removing a sulfur compound according to claim 5 or 6, wherein the supported amount of the active metal species is 1 to 50% by mass based on the total amount of the adsorbent as an element. The method for removing a sulfur compound according to claim 5 or 6, wherein the supported amount of the active metal species is 1 to 5% by mass based on the total amount of the adsorbent as an element. The hydrocarbon fuel is at least one hydrocarbon compound or oxygen-containing hydrocarbon selected from LPG, city gas, natural gas, naphtha, kerosene, light oil or ethane, ethylene, propane, propylene, butane, butene, methanol and dimethyl ether It is a compound, The removal method of the sulfur compound of any one of Claims 1-9. The method for removing a sulfur compound according to any one of claims 1 to 10, wherein the sulfur compound is carbonyl sulfide. Specific surface area is 100m ² The method for removing a sulfur compound according to claim 11, wherein the adsorbent is at least 10 g / g. The method for removing a sulfur compound according to claim 11 or 12, wherein an adsorbent containing cerium oxide calcined at a temperature of 300 to 600 ° C is used. The method for removing a sulfur compound according to any one of claims 1 to 13, wherein the adsorbent is used under conditions where hydrogen or oxygen is not added. A desulfurization means using an adsorbent for removing sulfur compounds having a sulfur adsorption capacity different from the adsorbent used in any one of claims 1 to 13 is provided on the upstream side or the downstream side of the desulfurization means. Item 15. The method for removing a sulfur compound according to any one of Items 1 to 14. The sulfur compound removal method according to any one of claims 1 to 15, wherein the sulfur compound in the hydrocarbon fuel or the oxygen-containing hydrocarbon fuel is desulfurized, and the resulting desulfurized fuel is used as a partial oxidation reforming catalyst. A method for producing hydrogen for a fuel cell, comprising contacting an autothermal reforming catalyst or a steam reforming catalyst. The method for producing hydrogen for fuel cells according to claim 16, wherein the partial oxidation reforming catalyst, autothermal reforming catalyst or steam reforming catalyst is a ruthenium-based or nickel-based catalyst. A fuel cell system comprising a hydrogen production system for carrying out the production method according to claim 16 or 17.

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