JP2009046626A - Desulfurization agent for liquid fuel and desulfurization method of liquid fuel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive and high-performance desulfurization agent which is usable for the desulfurization of liquid fuel at ≤80°C and also usable as the desulfurization agent for rough removal carried out in the desulfurization to very low sulfur level such as desulfurization for liquid fuel for a fuel cell. <P>SOLUTION: The desulfurization agent is used for desulfurizing the liquid fuel at ≤80°C, consists essentially of an inorganic oxide, and has ≥170 μmol ammonia adsorption volume per one gram of the desulfurization agent at 100°C. The desulfurization method of the liquid fuel uses the desulfurization agent. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a liquid fuel desulfurization agent, a liquid fuel desulfurization method using the desulfurization agent, a hydrogen production method, and a fuel cell system.

In recent years, fuel cells, which are attracting attention as a new energy technology due to environmental problems, convert chemical energy into electrical energy by electrochemically reacting oxygen with hydrogen and flammable substances such as CO and methane. Therefore, since it has the feature of high energy use efficiency, practical research has been actively conducted for consumer use, industrial use or automobile use. In this fuel cell, as a hydrogen source, liquefied natural gas mainly composed of methanol and methane, city gas mainly composed of this natural gas, synthetic liquid fuel made from natural gas, LP gas, and petroleum-based gas The use of hydrocarbon oils such as naphtha and kerosene has been proposed.
When fuel cells are used for consumer use or automobiles, the hydrocarbons other than methane, liquefied natural gas, city gas, and liquefied petroleum gas are liquid at room temperature and normal pressure, and are easy to store and handle. In particular, petroleum-based products are advantageous as a hydrogen source because their supply systems such as gas stations and dealers have been established. However, such hydrocarbon oil has a problem that the content of sulfur is higher than that of methanol or natural gas. In the case of producing hydrogen using a hydrocarbon oil, generally, a method of reforming the hydrocarbon oil in the presence of a reforming catalyst is used. In such reforming treatment, the reforming catalyst is poisoned by the sulfur content in the hydrocarbon oil. Therefore, from the viewpoint of catalyst life, the hydrocarbon oil is subjected to desulfurization treatment to reduce the sulfur content. It is necessary to reduce it below a predetermined value over a long period of time.

As a desulfurization method for petroleum hydrocarbons, many studies have been made so far. For example, Patent Document 1 describes a sulfur removal method using a desulfurization agent carrying an active metal component such as Ni, Zn, Cu or the like. Patent Document 2 describes a hydrocarbon compound desulfurization agent having a specific amount of Ag held in a porous carrier, and Patent Document 3 discloses a fuel containing a composite compound composed of a metal component and an inorganic oxide or activated carbon. A method for treating fuel oil using an oil treating agent is described, and Patent Document 4 further describes a desulfurizing agent obtained from a precursor formed by coprecipitation of nickel and zinc with alumina as a core. However, the desulfurization agents described in these patent documents all require an active metal such as a transition metal or a noble metal, and are very expensive and have a sulfur content in fuel such as kerosene before desulfurization. If it was too much, there was a problem in its life.
Regarding desulfurization of organic sulfur compounds, Patent Document 5 removes specific organic sulfur compounds contained in liquid hydrocarbons by bringing liquid hydrocarbons into contact with an adsorbent such as an oxidized transition metal-supported alumina-based adsorbent. Although a desulfurization method is described, such a method has not yet been sufficient in its adsorption performance.

JP 2006-117721 A JP 2006-176721 A JP 2002-249787 A JP 2004230317 A JP 2005-2317 A

  An object of the present invention is to provide an inexpensive and high-performance desulfurization agent that can be used for desulfurization of liquid fuel at a temperature of 80 ° C. or lower. Also provided is a desulfurization agent that can be used as a so-called “roughing” desulfurization agent in the first stage of the two-stage desulfurization method performed when desulfurizing liquid fuel for fuel cells to a very low sulfur level. There is to do. It is another object of the present invention to provide a method for producing hydrogen by reforming a desulfurized liquid fuel and a fuel cell system using the hydrogen.

That is, the present invention
(1) A desulfurization agent for use in desulfurization of liquid fuel at 80 ° C. or less, comprising an inorganic oxide as a main component and an ammonia adsorption amount of 170 μmol / g or more per gram of desulfurization agent ,
(2) A liquid fuel desulfurization method, wherein the liquid fuel is desulfurized at 80 ° C. or lower using the desulfurization agent described in (1) above.
(3) A method for producing hydrogen in which the liquid fuel is desulfurized by the method described in (2) above, and then the desulfurized fuel is partially oxidized reformed, autothermal reformed or steam reformed, and (4) (3 ) A fuel cell system using hydrogen obtained by the production method as described above,
Is to provide.

  According to the present invention, an inexpensive and high-performance desulfurization agent that can be used for desulfurization of liquid fuel at a temperature of 80 ° C. or less can be provided. In addition, a desulfurization agent that can be used as a roughing desulfurization agent can be provided in the first stage of the two-stage desulfurization method that is performed at the time of desulfurization to a very low sulfur level such as desulfurization of liquid fuel for fuel cells. . Furthermore, a method for desulfurizing a liquid fuel using the desulfurizing agent can be provided. In addition, hydrogen can be produced by reforming the desulfurized liquid fuel, and a fuel cell system can be provided using the hydrogen.

[Desulfurization agent for liquid fuel]
The desulfurizing agent of the present invention has an inorganic oxide as a main component and has an ammonia adsorption amount of 170 μmol / g or more per 1 g of the desulfurizing agent.
Any inorganic oxide can be used as long as the ammonia adsorption amount is in the above-mentioned range. Preferably, however, a porous inorganic oxide that can be used as a carrier for a desulfurizing agent usually improves the desulfurization performance. Specifically, silica, alumina, silica-alumina, zeolite, titania, zirconia, magnesia, silica-magnesia, zinc oxide, white clay, clay, diatomaceous earth, ALPO (Alminophosphate), SAPO (Silicoaluminophosphate), MCM (Mobil) 's composition of matter), activated carbon and the like can be used. These may be used alone or in combination of two or more.

  In the present invention, as the inorganic oxide, alumina and / or zirconia is preferably used because a desired ammonia adsorption amount is easily obtained and a Lewis acid point is large. From the above viewpoint, the desulfurizing agent of the present invention is preferably substantially composed only of alumina and / or zirconia, and is substantially composed only of alumina from the viewpoint of being inexpensive and simple to manufacture and excellent in desulfurization performance. Is more preferable. Here, “substantially” means that a small amount of other components may be included within a range that does not affect the effect of the present invention, and consists of alumina and / or zirconia alone, or alumina alone. Also included.

In the present invention, alumina having any structure such as α, κ, θ, δ, γ, η, χ, and ρ can be used as the alumina, but γ alumina is used because of its large surface area and easy availability. Is preferably used.
The desulfurizing agent of the present invention contains the inorganic oxide as a main component. Here, the “main component” means that the inorganic oxide is contained at least 50% by mass, preferably 70%. It means that it is contained by mass% or more, more preferably 90% by mass or more, and includes substantially 100% by mass.

  The desulfurizing agent of the present invention can contain an active metal component together with the inorganic oxide, but preferably does not carry the active metal. When a desulfurizing agent composed of an inorganic oxide not supporting active metal species and having an ammonia adsorption amount of 170 μmol / g or more is used, sufficient desulfurization performance can be obtained. For example, even if it is used for ordinary combustion applications, the environmental load is small. Fuel can be obtained. In the case of containing an active metal, the active metal is not particularly limited, and any active metal that can be normally supported on an inorganic oxide as a carrier can be used. Specifically, Ni, Co, Zn, Fe, Ag, Cu, Sn, Pd, Bi, Pt, Ru, Rh, Au, Mn, Mo, W, etc. are mentioned. The metal component loading is usually 0.5 to 80% by mass, preferably 5 to 70% by mass.

The desulfurizing agent of the present invention contains the above-mentioned inorganic oxide as a main component and has an ammonia adsorption amount at 100 ° C. of 170 μmol / g or more per 1 g of the desulfurizing agent.
The ammonia adsorption amount means a value obtained by measuring the ammonia adsorption amount by mass spectrometry when 0.5% NH ₃ / He is circulated at 100 ° C. for 1 hour. It can be measured by the method. The desulfurization agent of the present invention has an ammonia adsorption amount of 170 μmol / g or more per gram of the desulfurization agent. From the viewpoint of desulfurization performance, the adsorption amount is preferably 200 μmol / g or more, more preferably 250 μmol. / G or more, more preferably 300 μmol / g or more, still more preferably 350 μmol / g or more. The upper limit is not particularly limited, but usually the inorganic oxide is about 1000 μmol / g or less.

As the desulfurizing agent of the present invention, those having an ammonia adsorption amount in the above range are used, but those which satisfy the above range by heat treatment such as firing are preferably included.
The method for producing the desulfurizing agent of the present invention is not particularly limited as long as it satisfies the above ammonia adsorption amount, but from the viewpoint of desulfurizing performance, the desulfurizing agent precursor is preferably heat treated at 300 to 850 ° C. The desulfurizing agent precursor is preferably composed mainly of an inorganic oxide such as alumina and / or zirconia.
As inorganic oxides such as alumina and zirconia, those produced at a temperature of 200 to 1000 ° C. are usually used. However, in the present invention, when these are used as a desulfurizing agent, from the viewpoint of desulfurization performance. Heat treatment is preferably performed at 300 to 850 ° C. When the heat treatment temperature is lower than the above range, the amount of ammonia adsorbed decreases, and the desulfurization effect may be reduced. If it is higher than the above range, a part of the porous structure of the inorganic oxide support is broken, the surface area becomes small, and the desulfurization effect may be inferior. From the above viewpoint, the heat treatment temperature is more preferably 400 to 800 ° C, still more preferably 500 to 700 ° C. In addition, when the temperature at the time of manufacture of the inorganic oxide is between 300 to 850 ° C. and does not substantially come into contact with water or water vapor before the desulfurization treatment, the heat treatment as a pretreatment is not performed. There are cases where it is good.
The heat treatment time can be appropriately selected depending on the treatment temperature, but is usually 1 to 20 hours, preferably 2 to 5 hours.

In the present invention, the Lewis acid of the inorganic oxide is increased by heat treatment at a high temperature as described above. As a result, the ammonia adsorption amount increases, and as a result, the desulfurization performance of the liquid fuel using the desulfurizing agent is improved.
The heat treatment can be performed in any atmosphere of air, nitrogen, hydrogen, helium and a mixed gas of two or more thereof. However, from the viewpoint of easy availability, the atmosphere is air atmosphere and / or hydrogen atmosphere. It is preferable to carry out with. For example, the treatment may be performed in an air atmosphere and then in a hydrogen atmosphere. In this case, the desulfurization agent of the present invention can be obtained by performing at least one of the treatments at 300 to 850 ° C. This treatment can also be performed in a vacuum.
In the present invention, the heat treatment can be performed in the baking of the desulfurizing agent, in the subsequent pre-desulfurization treatment, or both.

Moreover, it is preferable that the desulfurization agent of this invention performs a desulfurization process by making it contact with liquid fuel, without making it contact substantially with water or water vapor | steam after the said heat processing. After the heat treatment, for example, the Lewis acid point on the surface of the desulfurizing agent may be decreased just by contact with moisture contained in the air. As a result, the ammonia adsorption amount of the catalyst may be decreased and the desulfurization performance may be deteriorated. Therefore, it is preferable that the desulfurizing agent of the present invention is not substantially brought into contact with water or water vapor after the heat treatment so that the value in the ammonia adsorption amount range can be maintained. Specifically, it is preferable to heat-treat the desulfurizing agent in a desulfurizing agent filling device that is put into a desulfurizing apparatus, because it can prevent contact with moisture after the heat treatment. It is also effective to fill the desulfurizer immediately after taking out from the heat treatment container or to fill in a dry room.
The shape of the desulfurizing agent is preferably powder, crushed, pellet, tablet, needle, sphere, honeycomb, or a state where powder is coated on another honeycomb.

  The desulfurizing agent of the present invention can be used for desulfurization of liquid fuels such as kerosene and light oil used for normal combustion applications, but desulfurization to a very low sulfur level such as desulfurization of liquid fuel for fuel cells is required. Can also be used. In this case, the desulfurization agent of the present invention is used as a so-called “rough removal” desulfurization agent that removes most of the sulfur content of the hydrocarbon-based liquid fuel used as a fuel for generating hydrogen in a fuel cell. It is preferably used as a first-stage desulfurization agent in the stage desulfurization method. When the hydrocarbon-based liquid fuel from which the sulfur content is roughly removed is passed through the second-stage fuel cell desulfurization agent, the life of the desulfurization agent can be extended. The second-stage desulfurizing agent is not particularly limited, and any conventionally known desulfurizing agent can be used.

[Method of desulfurization of liquid fuel]
In the liquid fuel desulfurization method of the present invention, the liquid fuel is desulfurized at 80 ° C. or lower using the above-mentioned desulfurizing agent.
In the present invention, the sulfur-containing liquid fuel to be desulfurized using the desulfurizing agent is not particularly limited. For example, alcohol, ether, naphtha, gasoline, kerosene, light oil, heavy oil, coal liquefied oil, GTL oil, Examples thereof include one selected from waste plastic oil and biofuel (biomass fuel), or a combination thereof. Among these, as the liquid fuel suitable for applying the desulfurizing agent of the present invention, kerosene, light oil or gasoline is preferable from the viewpoint of availability, and the above liquid fuel having a sulfur content of 80 mass ppm or less. Is more preferable, and JIS No. 1 kerosene having the above sulfur content is more preferable.

In the desulfurization method of the present invention, the sulfur compound contained in the liquid fuel as a sulfur content to be removed includes, for example, mercaptans, chain sulfides, cyclic sulfides, thiophenes, benzothiophenes, dibenzothiophenes, and the like. A sulfur compound is mentioned.
As a method of desulfurizing a sulfur-containing liquid fuel using the desulfurizing agent according to the present invention, a method of circulating an organic sulfur compound-containing liquid fuel in the desulfurizing agent, an organic sulfur compound in a container such as a tank in which the desulfurizing agent is fixed inside A method of standing or stirring the contained liquid fuel may be mentioned.
In the desulfurization method in the present invention, the desulfurization temperature is preferably 80 ° C. or less. If this desulfurization temperature is 80 degrees C or less, energy cost is low and it is economically advantageous. The lower limit of the desulfurization temperature is not particularly limited, and is appropriately selected in consideration of the fluidity of the liquid fuel to be desulfurized and the desulfurization activity of the desulfurizing agent. When the liquid fuel to be desulfurized is kerosene, the lower limit is about −40 ° C. from the viewpoint of fluidity. A preferable desulfurization temperature is −30 to 60 ° C., and more preferably 0 to 40 ° C.

The desulfurization conditions other than the temperature are not particularly limited, and can be appropriately selected according to the properties of the liquid fuel to be desulfurized. Specifically, when desulfurization is performed by passing hydrocarbons such as JIS No. 1 kerosene as fuel in a desulfurization tower filled with the desulfurization agent according to the present invention in a liquid phase in an upward or downward flow, the desulfurization temperature is room temperature. extent, the pressure is atmospheric圧乃Itaru 1 MPa · G about, liquid hourly hourly space velocity (LHSV) can be 30 hr ^-1 or less, more 20 hr ^-1 or less, and more preferably to desulfurization treatment with 5 hr ^-1 following conditions. At this time, if necessary, a small amount of hydrogen may coexist.

By the desulfurization treatment using the desulfurizing agent of the present invention, in the present invention, the sulfur content of the liquid fuel can be reduced to, for example, 10 mass ppm or less, preferably 2 mass ppm or less, more preferably 1 mass ppm or less. In addition, by using the desulfurizing agent of the present invention as, for example, the first-stage desulfurizing agent of the above-mentioned two-stage desulfurization, the sulfur content of the liquid fuel is finally reduced to, for example, 0.5 mass ppm or less, preferably 0 .05 mass ppm or less.
In this case, it is possible to suppress the poisoning of the subsequent reforming catalyst due to the sulfur content as much as possible and to function stably for a long period of time. The clean-up desulfurization agent (second-stage desulfurization agent) is not particularly limited as long as the sulfur content can be reduced to 0.5 ppm or less, and any known adsorptive desulfurization agent or hydrodesulfurization agent may be used.

[Method for producing hydrogen]
Next, in the present invention, the fuel desulfurized as described above is subjected to steam reforming, partial oxidation reforming or autothermal reforming, and more specifically, a steam reforming catalyst, partial oxidation reforming catalyst or Hydrogen for fuel cells is produced by contacting with an autothermal reforming catalyst.

There is no restriction | limiting in particular as a reforming catalyst used here, Arbitrary things can be suitably selected and used from the well-known things conventionally known as a hydrocarbon reforming catalyst. As such a reforming catalyst, for example, a catalyst in which noble metal such as nickel or ruthenium, rhodium or platinum is supported on a suitable carrier can be exemplified. The supported metal may be one kind or a combination of two or more kinds. Among these catalysts, those supporting nickel (hereinafter referred to as nickel-based catalyst) and ruthenium (hereinafter referred to as ruthenium-based catalyst) or those supporting rhodium are preferable.
The carrier for supporting the reforming catalyst preferably contains manganese oxide, cerium oxide, zirconium oxide or the like, and particularly preferably a carrier containing at least one of these. These have a great effect of suppressing carbon deposition during steam reforming, partial oxidation reforming or autothermal reforming.

In the case of a nickel-based catalyst, the supported amount of nickel is preferably in the range of 3 to 60% by mass based on the carrier. When the supported amount is within the above range, the activity of the steam reforming catalyst, the partial oxidation reforming catalyst or the autothermal reforming catalyst is sufficiently exhibited, and it is economically advantageous. In view of catalyst activity and economy, the more preferable amount of nickel is 5 to 50% by mass, and particularly preferably 10 to 30% by mass.
In the case of a ruthenium-based catalyst, the supported amount of ruthenium is preferably in the range of 0.05 to 10% by mass based on the carrier. When the supported amount of ruthenium is within the above range, the activity of the steam reforming catalyst, the partial oxidation reforming catalyst or the autothermal reforming catalyst is sufficiently exhibited and it is economically advantageous. Considering catalytic activity and economy, the more preferable loading of ruthenium is 0.05 to 5% by mass, and particularly preferably 0.1 to 2% by mass.

As a reaction condition in the steam reforming treatment, steam / carbon (molar ratio), which is a ratio of steam and carbon derived from fuel oil, is usually selected in the range of 1.5 to 10. When the steam / carbon (molar ratio) is 1.5 or more, the amount of hydrogen generated is sufficient, and when it is 10 or less, excess water vapor is not required, so heat loss is small and hydrogen production can be performed efficiently. . From the above viewpoint, the steam / carbon (molar ratio) is preferably in the range of 1.5 to 5, and more preferably in the range of 2 to 4.
Moreover, it is preferable to perform steam reforming while maintaining the inlet temperature of the steam reforming catalyst layer at 630 ° C. or lower. If the inlet temperature is 630 ° C. or lower, thermal decomposition of the fuel oil does not occur, so that carbon deposition on the catalyst or reaction tube wall via the carbon radical is unlikely to occur. From the above viewpoint, the inlet temperature of the steam reforming catalyst layer is preferably 600 ° C. or lower. The catalyst layer outlet temperature is not particularly limited, but is preferably in the range of 650 to 800 ° C. When the temperature is 650 ° C. or higher, the amount of hydrogen generated is sufficient, and when it is 800 ° C. or lower, the reaction apparatus does not need to be made of a heat-resistant material, which is economically preferable.

As reaction conditions in the partial oxidation reforming treatment, the pressure is usually normal pressure to 5 MPa · G, the temperature is 400 to 1100 ° C., the oxygen (O ₂ ) / carbon (molar ratio) is 0.2 to 0.8, and the liquid The space-time velocity (LHSV) is 0.1 to 100 hr ⁻¹ .
As reaction conditions in the autothermal reforming treatment, the pressure is usually normal pressure to 5 MPa · G, the temperature is 400 to 1100 ° C., the steam / carbon (molar ratio) is 0.1 to 10, and oxygen (O ₂ ). / Carbon (molar ratio) is 0.1 to 1, liquid hourly space velocity (LHSV) is 0.1 to 2 hr ⁻¹ , and gas hourly space velocity (GHSV) is 1000 to 100,000 hr ⁻¹ .
Note that CO in the hydrogen-containing gas obtained by steam reforming, partial oxidation reforming or autothermal reforming is further converted to H ₂ and CO ₂ by a shift reaction at a later stage to further increase the hydrogen concentration. . Thus, according to the method of the present invention, hydrogen for fuel cells can be produced efficiently.
A fuel cell system using a liquid fuel is usually composed of a fuel supply device, a desulfurization device, a reforming device, and a fuel cell, and the hydrogen produced by the method of the present invention is supplied to the fuel cell.

[Fuel cell system]
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 flows into the desulfurizer 23 via the fuel pump 22. The desulfurizer is filled with the desulfurizing agent according to the present invention. As described above, this desulfurization is performed in two stages, and the desulfurization agent of the present invention can be filled in the first stage. The fuel desulfurized in the desulfurizer 23 is mixed with water from the water tank via the water pump 24, introduced into the vaporizer 1, vaporized, and then fed into the reformer 31.
The inside of the reformer 31 is filled with the above-described reforming catalyst, and the above-described steam reforming reaction is performed from the fuel mixture (mixed gas containing steam and desulfurized liquid fuel) fed into the reformer 31. Hydrogen is produced.

The hydrogen produced in this way 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 catalysts 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 oxidizer 33. The mixture etc. can be mentioned.
The fuel cell 34 is a solid polymer 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 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 the heat generated during the reaction, a heat exchanger 37B that exchanges heat taken by the heat exchanger 37A with water, a cooler 37C, and these heat exchanges. The hot water obtained in the heat exchanger 37B can be effectively used in other facilities. The pumps 37A and 37B and the pump 37D circulate the refrigerant to the cooler 37C.

  In this example, each property was measured and evaluated as follows.

[Measurement of sulfur content in liquid fuel]
In accordance with the microcoulometric titration method defined in JIS K 2541-2, the amount was determined using a TS-03 apparatus manufactured by Mitsubishi Chemical Corporation. The calibration curve was prepared by measuring a toluene solution of dibutyl sulfide (purity 99% or more). The sample was measured in the same manner as the calibration curve solution, and the sulfur content (wtppm) in the sample was calculated from the sulfur amount (μg) obtained from the calibration curve and the sample injection amount (mg).

Example 1
(1) Production of desulfurization agent 1 and evaluation of desulfurization performance Commercially available alumina (catalyst conversion) was pulverized to a particle size of 100 μm or less with a mortar, filled with 2.5 cc in a deflower, Heat treatment was performed at 300 ° C. for 3 hours while flowing hydrogen (as described in Table 1) to obtain a desulfurizing agent 1. Thereafter, kerosene having the following properties was passed at room temperature (30 ° C.) at a liquid space velocity (LHSV) of 20 / h without removing the desulfurizing agent from the desulfurizer. Table 1 shows the results of measuring the sulfur concentration in the kerosene obtained by the method described above.
JIS-1 kerosene / distillation properties: initial distillation temperature 156 ° C, 10% distillation temperature 170 ° C, 30% distillation temperature 185 ° C, 50% distillation temperature 201 ° C, 70% distillation temperature 224 ° C, 90% distillation Outlet temperature 253 ° C, end point 275 ° C
・ Sulfur content: 14 mass ppm
(2) Measurement of ammonia adsorption amount (a) 0.1 g of commercially available alumina (catalyst conversion) used in the above (1) pulverized to a particle size of 100 μm or less with a mortar in a cell for measuring ammonia adsorption amount. Heat treatment was performed at the temperature and atmosphere shown in 1 to obtain a desulfurizing agent 1. Thereafter, the temperature is lowered to 100 ° C., and after the temperature is stabilized, 0.5% NH ₃ / He is circulated in the cell at 100 ° C. for 1 hour. After 1 hour, purge with He, stabilize the baseline, raise the temperature to 710 ° C. at 20 ° C./min, and measure ammonia desorption by mass spectrometry. 0.5% NH ₃ / He was used for calibration.
(B) The data obtained by performing the same operation as in (a) except that ammonia was not adsorbed was used as the background, and the value subtracted from the value obtained in the previous (a) was taken as the ammonia adsorption amount. The results are shown in Table 1.

Examples 2 to 6 (Production of desulfurizing agents 2 to 6, evaluation of ammonia adsorption amount and desulfurization performance)
Similar to Example 1 except that commercial alumina (pulverized in Examples 2 to 5 and manufactured by Mizusawa Chemical in Example 6) pulverized to a particle size of 100 μm or less in a mortar was used and the heat treatment conditions shown in Table 1 were used. Production of desulfurizing agents 2-6, ammonia adsorption amount and desulfurization performance were measured. The results are shown in Table 1.

Example 7 (Production of desulfurizing agent 7, evaluation of ammonia adsorption amount and desulfurization performance)
(1) 27.6 g of zirconyl nitrate hydrate was dissolved in 200 ml of ion-exchanged water, and 200 ml of ion-exchanged water in which 16.7 g of sodium hydroxide was dissolved was added thereto to precipitate a hydroxide. The precipitate was washed with water and dried at 120 ° C. overnight. After the drying, it was calcined at 500 ° C. for 3 hours under air. The calcined product was pulverized to a particle size of 100 μm or less with a mortar, 2.5 cc of which was filled in a desulfurizer, and heat treated at 600 ° C. for 3 hours under hydrogen flow in the desulfurizer to obtain a desulfurizing agent 7. About the obtained desulfurization agent 7, operation similar to Example 1 was performed and the sulfur content density | concentration was measured. The results are shown in Table 1.
(2) In the operation of the ammonia adsorption amount in Example 1, a commercially available alumina pulverized with a mortar to a particle size of 100 μm or less, and a fired product obtained by baking at 500 ° C. for 3 hours in the above (1) to a particle size of 100 μm or less with a mortar The ammonia adsorption amount was measured in the same manner as in Example 1 except that the heat treatment conditions shown in Table 1 were used instead of the pulverized ones. The results are shown in Table 1.

Comparative Examples 1 and 2 (Production of desulfurization agents 8 and 9, evaluation of ammonia adsorption amount and desulfurization performance)
2.5 cc of commercially available alumina (catalyst conversion) pulverized to a particle size of 100 μm or less in a mortar is charged into a desulfurizer, and 120 ° C. (Comparative Example 1) or 900 ° C. (Comparative Example) under hydrogen flow in the desulfurizer. The desulfurization agents 8 and 9 were obtained by heat treatment for 3 hours under the condition 2). About each of the obtained desulfurization agents 8 and 9, operation similar to Example 1 was performed and the sulfur content density | concentration was measured. The results are shown in Table 1.
Regarding the ammonia adsorption amount, the above-mentioned commercially available alumina (made by catalytic conversion) pulverized in a mortar to a particle diameter of 100 μm or less was used, except that the heat treatment conditions in the cell for measuring the ammonia adsorption amount were as shown in Table 1. Performed as in Example 1. The results are shown in Table 1.

Comparative Example 3 (Production of desulfurizing agent 10, evaluation of ammonia adsorption amount and desulfurization performance)
Desulfurizing agent 10 was prepared by filling 2.5 cc of commercially available silica (manufactured by Mizusawa Chemical Co., Ltd.) pulverized to a particle size of 100 μm or less in a mortar into a desulfurizer and heat-treating it at 600 ° C. for 3 hours under hydrogen flow. Got. The obtained catalyst 10 was subjected to the same operation as in Example 1, and the sulfur concentration was measured. The results are shown in Table 1.
Regarding the ammonia adsorption amount, the above-mentioned commercially available silica (manufactured by Mizusawa Chemical Co., Ltd.) pulverized with a mortar to a particle size of 100 μm or less was used, except that the heat treatment conditions in the cell for measuring the ammonia adsorption amount were as shown in Table 1. Performed as in Example 1. The results are shown in Table 1.

  The desulfurization agent of the present invention can be used for desulfurization of liquid fuel, and provides an inexpensive and high-performance desulfurization agent. Therefore, the desulfurization agent for kerosene, light oil and the like used for combustion is also suitable for desulfurization of liquid fuel for fuel cells. It can also be used for desulfurization to very low sulfur levels, such as desulfurization. Moreover, the liquid processing fuel obtained using this desulfurization agent can be used suitably for manufacture of hydrogen for fuel cells.

It is a schematic flowchart which shows an example of the fuel cell system of this invention.

Explanation of symbols

1: Vaporizer 11: Water supply pipe 12: Fuel introduction pipe 15: Connection pipe 21: Fuel tank 22: Pump 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

Claims (12)

  A desulfurization agent for use in desulfurization of liquid fuel at 80 ° C. or less, comprising an inorganic oxide as a main component, and an ammonia adsorption amount at 100 ° C. of 170 μmol / g or more per 1 g of desulfurization agent. Agent.   The desulfurization agent according to claim 1, wherein the ammonia adsorption amount at 100 ° C is 300 µmol / g or more per 1 g of the desulfurization agent.   The desulfurization agent according to claim 1 or 2, wherein the inorganic oxide is alumina and / or zirconia.   The desulfurization agent according to any one of claims 1 to 3, which consists essentially of alumina.   The desulfurization agent according to any one of claims 1 to 4, wherein the inorganic oxide is γ-alumina.   The desulfurization agent according to any one of claims 1 to 5, which does not carry an active metal.   The desulfurization agent in any one of Claims 1-6 obtained by heat-processing the desulfurization agent precursor which has an inorganic oxide as a main component at 300-850 degreeC in air atmosphere and / or hydrogen atmosphere.   The desulfurization agent according to claim 7, wherein the desulfurization agent precursor is made of alumina and / or zirconia.   A method for desulfurizing a liquid fuel, wherein the liquid fuel is desulfurized at 80 ° C. or lower using the desulfurizing agent according to claim 1.   The method for desulfurizing a liquid fuel according to claim 9, further comprising a step of bringing the desulfurizing agent according to claim 7 or 8 into contact with the liquid fuel without being substantially brought into contact with water or water vapor after the heat treatment.   11. The method for producing hydrogen according to claim 9, wherein after desulfurizing the liquid fuel, the desulfurized fuel is subjected to partial oxidation reforming, autothermal reforming, or steam reforming.   A fuel cell system using hydrogen obtained by the production method according to claim 11 as a raw material.

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