Reactor

Abstract

To provide a novel technology that reduces the temperature bias of the catalyst part producing hydrocarbon by the reaction according to the FT method.SOLUTION: A reaction device 20 includes a reactor 22 in which multiple tubular reaction tubes 22a are arranged in parallel, and a catalyst part 24 containing the FT catalyst 24a, which is packed in the inside of the reaction tube and produces hydrocarbon by the reaction according to the FT method using carbon monoxide and hydrogen. It is configured so as the difference between the gas temperature before the carbon monoxide-containing gas flows into the reaction tube and the temperature in the high temperature region where the catalyst part 24 has the highest temperature when producing hydrocarbon to be 30°C or less.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to the technology of catalysts and catalyst-packed reactors used in the production of hydrocarbons. [Background technology]

[0002] As a method for effectively utilizing carbon dioxide contained in exhaust gases, etc., a method for producing liquid hydrocarbons with high energy density from carbon dioxide and hydrogen in the presence of a catalyst has been studied (for example, Patent Document 1). In addition, the Fischer-Tropsch process (hereinafter, appropriately referred to as the "FT process") is known as a method for producing hydrocarbons using hydrogen and carbon monoxide (see Non-Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 7-80309 [Non-patent literature]

[0004] [Non-Patent Document 1] Energy & Fuels, Vol. 23, 4195(2009) Summary of the Invention [Problem to be solved by the invention]

[0005] The catalysts used in the FT process mainly contain metals such as cobalt, ruthenium, and iron. In addition, the catalytic reaction in the FT process is an exothermic reaction, and there is a tendency for more heat to be generated upstream of the catalyst layer. Therefore, some kind of ingenuity is required to make the reaction temperature uniform throughout the FT catalyst layer.

[0006] The present invention has been made in view of the above circumstances, and one of its exemplary objectives is to provide a new technology for reducing the temperature bias of a catalyst part that produces hydrocarbons through a reaction by the FT method. [Means for solving the problem]

[0007] In order to solve the above problems, a reaction apparatus according to one embodiment of the present invention includes a reactor in which a plurality of cylindrical reaction tubes are arranged in parallel, and a catalyst section that is filled inside the reaction tube and contains a catalyst that produces hydrocarbons by a reaction using carbon monoxide and hydrogen by the FT method. The reaction apparatus is configured so that the difference between the gas temperature before the carbon monoxide-containing gas flows into the reaction tube and the temperature of the high-temperature region that becomes the highest in the catalyst section when producing hydrocarbons is 30°C or less. Effect of the Invention

[0008] According to one aspect of the present invention, it is possible to reduce the temperature bias of the catalyst portion that produces hydrocarbons. [Brief description of the drawings]

[0009] [Figure 1] 1 is a schematic diagram showing a schematic configuration of a catalyst system including a reaction apparatus according to a first embodiment. [Diagram 2] FIG. 1 is a schematic diagram showing a schematic configuration of a reaction apparatus according to a first embodiment. [Diagram 3] FIG. 1 is a schematic diagram showing a schematic configuration of a reaction apparatus according to a second embodiment. [Figure 4] FIG. 13 is a schematic diagram showing a schematic configuration of a reaction apparatus according to a third embodiment. [Diagram 5] FIG. 13 is a schematic diagram showing a schematic configuration of a reaction apparatus according to a fourth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] First, the embodiments of the present invention are listed. A reaction apparatus according to an embodiment of the present invention comprises a reactor in which a plurality of cylindrical reaction tubes are arranged in parallel, and a catalyst section that is filled inside the reaction tube and contains a catalyst that produces hydrocarbons by a reaction using carbon monoxide and hydrogen by the FT method. The reaction apparatus is configured so that the difference between the gas temperature before the carbon monoxide-containing gas flows into the reaction tube and the temperature of the high-temperature region that becomes the highest in the catalyst section when producing hydrocarbons is 30° C. or less.

[0011] Heat generation tends to concentrate in the end region of the catalyst section on the side where carbon monoxide flows in. This results in a large temperature bias in the catalyst section. According to this embodiment, the temperature rise in the high-temperature region, which becomes the hottest in the catalyst section when generating hydrocarbons, is kept to 30°C or less compared to the gas temperature before the carbon monoxide-containing gas flows into the catalyst section, thereby reducing the temperature bias in the catalyst section. As a result, a stable catalytic reaction can be obtained in the catalyst section.

[0012] The catalyst may be filled in the reaction tube such that the amount of catalyst filled in the upstream half of the reaction tube is 50 to 90 mass % of the amount of catalyst filled in the downstream half of the reaction tube, which suppresses heat generation due to the reaction in the upstream side of the reaction tube and reduces temperature bias in the catalyst section.

[0013] The plurality of reaction tubes may include a first reaction tube filled with a first amount of catalyst and a second reaction tube filled with a second amount of catalyst different from the first amount, thereby making it possible to generate a difference in heat generation due to the reaction between the first reaction tube and the second reaction tube.

[0014] The reaction tube may be configured so that the cross-sectional area increases toward the downstream side. This suppresses heat generation due to the reaction on the upstream side of the reaction tube. The expanded diameter portion in which the cross-sectional area increases toward the downstream side may be provided on the entire reaction tube or on a part of the reaction tube.

[0015] The volume of the upstream half of the reaction tube may be 50 to 90% of the volume of the downstream half, thereby suppressing heat generation due to the reaction on the upstream side of the reaction tube.

[0016] The cross-sectional area of ​​the upstream end of the reaction tube may be 50 to 90% of the cross-sectional area of ​​the downstream end, thereby suppressing heat generation due to the reaction on the upstream side of the reaction tube.

[0017] The reaction tube may have a heat dissipation mechanism arranged so that the heat dissipation of the upstream half is higher than that of the downstream half, thereby suppressing the temperature rise in the upstream side of the reaction tube.

[0018] The heat dissipation mechanism may be a heat dissipation fin provided in the upstream half region of the reaction tube, thereby suppressing the temperature rise in the upstream side of the reaction tube.

[0019] The heat dissipation mechanism may have a first cooling mechanism for cooling a first region of the reaction tube with a first coolant and a second cooling mechanism for cooling a second region of the reaction tube downstream of the first region with a second coolant, thereby further reducing the temperature difference among the multiple regions.

[0020] Any combination of the above components and any conversion of the present invention between a method, an apparatus, a system, etc. are also valid aspects of the present invention. Appropriate combinations of the above elements may also be included in the scope of the invention for which patent protection is sought by this patent application.

[0021] The present invention will be described below with reference to the drawings based on preferred embodiments. The embodiments are illustrative and do not limit the invention, and all features and combinations thereof described in the embodiments are not necessarily essential to the invention. The same or equivalent components, members, and processes shown in each drawing are given the same reference numerals, and duplicated descriptions are omitted as appropriate. The scale and shape of each part shown in each drawing are set for convenience to facilitate explanation, and are not to be interpreted as being limiting unless otherwise specified. In addition, even if the components are the same, the scale, etc. may differ slightly between each drawing. In addition, when terms such as "first" and "second" are used in this specification or claims, unless otherwise specified, they do not represent any order or importance, but are intended to distinguish one configuration from another.

[0022] (Catalyst System) First, an example of a catalyst system for producing hydrocarbons using a reactor according to the present embodiment will be described. Fig. 1 is a schematic diagram showing a schematic configuration of a catalyst system including a reactor according to the first embodiment. The catalyst system 10 shown in Fig. 1 includes a reverse shift reactor 12 arranged on the upstream side and an FT reactor 14 arranged on the downstream side of the reverse shift reactor 12.

[0023] In the reverse shift reactor 12, a raw material gas containing hydrogen and carbon dioxide is introduced from the upstream side, and carbon monoxide is produced from carbon dioxide by a reverse shift reaction using the contained reverse shift catalyst. In the FT reactor 14, the carbon monoxide produced in the reverse shift reactor 12 and a gas containing hydrogen are introduced, and gaseous or liquid hydrocarbons are produced by a reaction according to the FT method using the contained FT catalyst. The reactor described in each of the following embodiments corresponds to the above-mentioned FT reactor 14. Note that the reactor according to each of the embodiments may be a reactor in which the reverse shift reactor 12 and the FT reactor 14 are integrated.

[0024] [First embodiment] The schematic configuration of the reaction apparatus according to the first embodiment will be described. Fig. 2 is a schematic diagram showing the schematic configuration of the reaction apparatus according to the first embodiment. The reaction apparatus 20 shown in Fig. 2 includes a reactor 22 configured to discharge hydrocarbons generated from a raw material gas introduced from an inlet 20a on the upstream side from an outlet 20b on the downstream side, and a catalyst section 24 including an FT catalyst 24a that generates hydrocarbons by a reaction according to the FT method using carbon monoxide and hydrogen contained in the raw material gas.

[0025] In the reactor 22, a plurality of cylindrical reaction tubes 22a are arranged in parallel. A space 26 is provided around the reaction tubes 22a, through which a medium for heating or cooling flows as necessary. In the catalyst section 24, each reaction tube 22a is filled with pellet-shaped FT catalysts 24a that cause a reaction by the FT method. In the FT catalysts 24a, hydrocarbons are produced from carbon monoxide and hydrogen by a reaction by the FT method.

[0026] The reaction device 20 produces CH4 and C2-C4 components, which are gaseous hydrocarbons having 1 to 4 carbon atoms, such as methane, ethane, propane, and butane, and C5+ components, which are hydrocarbons having 5 or more carbon atoms and are oil components that are liquid at normal pressure (for example, linear alkanes with a carbon number n of 5 or more), and performs gas-liquid separation of the gas components and oil components, and in some cases performs fractional distillation to extract the desired components.

[0027] In the FT catalyst 24a filled in the reaction tube 22a, the reaction by the FT method is an exothermic reaction, so heat tends to concentrate in the end region R of the catalyst section 24 on the side where carbon monoxide flows in. Therefore, the temperature of the end region R of the catalyst section 24 tends to rise, and if left as is, the temperature bias will become large throughout the catalyst section 24. Therefore, the reaction device 20 according to the first embodiment is configured so that the difference between the gas temperature before the carbon monoxide-containing gas flows into the reaction tube 22a and the temperature of the high-temperature region that becomes the hottest in the catalyst section 24 when producing hydrocarbons is 30°C or less.

[0028] This makes it possible to suppress the temperature rise of the high temperature region (e.g., end region R) in the catalytic section 24, which becomes the hottest when producing hydrocarbons, to 30°C or less compared to the gas temperature immediately before the carbon monoxide-containing gas flows into the reaction tube 22a, thereby reducing the temperature bias in the catalytic section 24. As a result, a stable catalytic reaction in the catalytic section 24 can be obtained.

[0029] In the reaction apparatus 20 according to the present embodiment, in order to suppress a local temperature rise in the end region R, the FT catalyst 24a is filled in the reaction tube 22a so that the amount of the FT catalyst 24a filled in the region R1 of the upstream half (or 1 / 3) of the reaction tube 22a is 50 to 90 mass % of the amount of the FT catalyst 24a filled in the region R2 of the downstream half (or 2 / 3) of the reaction tube 22a. This suppresses heat generation due to the reaction on the upstream side of the reaction tube 22a, and reduces temperature bias in the catalyst section 24. In this specification, the "upstream half" refers to a portion of the length from the end of the reaction tube 22a on the side where the carbon monoxide-containing gas flows in to the half of the length, based on the length in the central axis direction of the reaction tube 22a, and the "downstream half" refers to a portion of the length from the end of the reaction tube 22a on the side where the hydrocarbon is discharged to the half of the length, based on the length in the central axis direction of the reaction tube 22a.

[0030] In addition, the condition that the amount of the catalyst packed on the upstream side is 50 to 90% by mass of the catalyst packed on the downstream side may be satisfied by each of the reaction tubes 22a, or may be satisfied by an average value of all the reaction tubes 22a. For example, if the amount of the FT catalyst 24a packed in the upstream half of all the reaction tubes 22a is 50 to 90% by mass of the amount of the FT catalyst 24a packed in the downstream half of all the reaction tubes 22a, the amount of the FT catalyst 24a packed on the upstream side of some of the reaction tubes 22a may exceed 90% by mass of the amount of the FT catalyst 24a packed on the downstream side, or may be less than 50% by mass.

[0031] In this way, the multiple reaction tubes 22a have a first reaction tube 22a1 filled with a first amount of catalyst and a second reaction tube 22a2 filled with a second amount of catalyst different from the first amount. This allows a difference in heat generation due to the reaction between the first reaction tube 22a1 and the second reaction tube 22a2. In addition, the amount of the FT catalyst 24a filled in the reaction tube 22a in the region where the temperature tends to be high may be reduced in consideration of the temperature distribution when all the reaction tubes 22a are filled to the full with the FT catalyst 24a. For example, as shown in FIG. 2, the multiple reaction tubes 22a may be arranged so that the amount of the FT catalyst 24a filled in the reaction tube 22a increases from the outer periphery side to the center of the cylindrical reactor 22. Alternatively, the multiple reaction tubes 22a may be arranged so that the amount of the FT catalyst 24a filled in the reaction tube 22a decreases from the outer periphery side to the center of the cylindrical reactor 22.

[0032] [Second embodiment] FIG. 3 is a schematic diagram showing the outline of the reactor according to the second embodiment. The same components as those of the reactor 20 according to the first embodiment are denoted by the same reference numerals and will not be described. The reactor 30 according to the second embodiment is configured so that the cross-sectional area S of the reaction tube 32a provided in the reactor 32 increases toward the downstream side in order to suppress heat generation on the upstream side of the catalyst section 24. As a result, the amount of FT catalyst 24a packed in the upstream half region R1 of the reaction tube 32a is less than the amount of FT catalyst 24a packed in the downstream half region R2, so that heat generation due to the reaction on the upstream side of the reactor 32 is suppressed.

[0033] In addition, the reaction tube 32a may have a volume V1 of the upstream half that is 50-90% of a volume V2 of the downstream half. In addition, the reaction tube 32a may have a cross-sectional area S1 of the upstream end that is 50-90% of a cross-sectional area S2 of the downstream end. This suppresses heat generation due to the reaction on the upstream side of the reaction tube 32a.

[0034] [Third embodiment] FIG. 4 is a schematic diagram showing the outline of the reactor according to the third embodiment. The same components as those in the reactor 20 according to the first embodiment are denoted by the same reference numerals and will not be described. As described in the above-mentioned embodiments, in the FT reactor according to each embodiment, the temperature bias of the catalyst part is reduced by suppressing heat generation on the upstream side of the reactor. On the other hand, the reactors according to the third and fourth embodiments reduce the temperature bias of the catalyst part by heat dissipation design.

[0035] In the reaction apparatus 40 shown in FIG. 4, the reaction tube 22a has a heat dissipation mechanism 42 provided so that the heat dissipation in the upstream half region R1 is higher than that in the downstream half region R2. Specifically, the heat dissipation mechanism 42 has a disk-shaped heat dissipation fin 42a in the region R1, in which a plurality of holes through which the reaction tube 22a penetrates are formed. The heat dissipation fin 42a increases the heat dissipation area when the reaction heat generated in the catalyst part 24 filled in the reaction tube 22a is dissipated to the space 26, so that the temperature rise of the catalyst part 24 close to the region where the heat dissipation fin 42a contacts the reaction tube 22a can be reduced. This suppresses the temperature rise on the upstream side of the reaction tube 22a.

[0036] [Fourth embodiment] FIG. 5 is a schematic diagram showing a schematic configuration of a reaction apparatus according to a fourth embodiment. The same components as those of the reaction apparatus 20 according to the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted as appropriate. The heat dissipation mechanism 52 of the reaction apparatus 50 shown in FIG. 5 has a first heat dissipation mechanism 52a for cooling the first region R1' of the reaction tube 22a with a first refrigerant C1, and a second cooling mechanism 52b for cooling the second region R2' of the reaction tube 22a with a second refrigerant C2. The second region R2' is located downstream of the reaction tube 22a from the first region R1'.

[0037] The first refrigerant C1 can control the temperature on the upstream side of the reaction tube 22a by flowing through the space 26a located on the upstream side of the reactor 22. The second refrigerant C2 can control the temperature on the downstream side of the reaction tube 22a by flowing through the space 26b located on the downstream side of the reactor 22. The refrigerants C1 and C2 are not particularly limited, but water or refrigerant oil is used. By changing the type or flow rate of the refrigerants C1 and C2, the cooling capacity of the multiple regions R1' and R2' can be individually controlled. This can further reduce the temperature difference between the multiple regions.

[0038] In each of the above-mentioned embodiments, the form of each catalyst is not particularly limited, and may be, for example, a powder or a granular compact consisting of an aggregate of powder. The shape of the catalyst that is a granular compact is not particularly limited, and may be, for example, cylindrical, prismatic, spherical, or irregular. The particle size (maximum width) of the granular compact may be 1 mm or more and 50 mm or less. The particle size (maximum width) of the catalyst powder may be 1 μm or more and less than 1000 μm.

[0039] The reverse shift catalyst may contain metallic copper, or copper oxide (CuO), or both. During the time that the copper-based catalyst body functions as a catalyst, the copper-based catalyst body contains at least metallic copper. Therefore, the catalyst is subjected to a reduction treatment before being used in the reaction. Before the reduction treatment, the copper-based catalyst body often contains copper oxide.

[0040] The content of the copper component in the copper-based catalyst body is preferably 20 to 100 mass% based on the mass of the entire copper-based catalyst body when the amount of the copper component contained in the copper-based catalyst body is converted into the amount of metallic copper.

[0041] The copper-based catalyst body may further contain zinc oxide (ZnO). When the copper-based catalyst body contains zinc oxide, liquid hydrocarbons can be produced more efficiently. When the amount of copper element contained in the copper-based catalyst body is converted into the amount of copper oxide, the proportion of the amount of zinc oxide is preferably 10 to 70 mass%, and more preferably 20 to 50 mass%, based on the total amount of copper oxide and zinc oxide.

[0042] The copper-based catalyst body may further contain a carrier that supports the copper component. When the copper-based catalyst body contains zinc oxide, the zinc oxide is usually also supported on the carrier. The carrier is preferably alumina such as γ-alumina. The content of the carrier in the copper-based catalyst body is, for example, 0.5 to 60 mass%, preferably 1 to 50 mass%, and more preferably 1 to 40 mass%, based on the total content of copper, zinc oxide, and alumina. The copper content here means the amount of the copper component contained in the copper-based catalyst body converted into the amount of metallic copper.

[0043] A copper-based catalyst body containing a copper component and zinc oxide can be obtained, for example, by a method including a step of forming a precipitate containing copper and zinc by a coprecipitation method, and a step of calcining the formed precipitate. The precipitate includes, for example, hydroxides, carbonates, or composite salts of copper and zinc. A copper-based catalyst body containing a copper component, zinc oxide, and a support can be obtained by forming a precipitate containing copper and zinc by a coprecipitation method from a solution containing a support (for example, alumina).

[0044] The calcined body containing the copper component and zinc oxide formed by calcination may be powdered, and the powder may be further molded to form a granular compact. Examples of methods for molding the powder include extrusion molding and tablet molding. A molded body can also be obtained by molding a mixture containing the powder of the calcined body and carbon black.

[0045] The FT catalyst 24a is preferably an iron-based catalyst body containing an iron component including metallic iron, iron oxide, or both, and at least one added metal selected from the group consisting of alkali metals and alkaline earth metals. The FT catalyst 24a may also be an iron-based catalyst body-copper-based catalyst body containing a copper component in addition to the iron component. While the iron-based catalyst body functions as a catalyst, the iron-based catalyst body usually contains at least metallic iron. Therefore, the catalyst is usually subjected to a reduction treatment before being used in a reaction. The iron-based catalyst body before the reduction treatment usually contains iron oxide (e.g., Fe3O4 or Fe2O3).

[0046] The content of the iron component in the iron-based catalyst body is preferably 5 to 100 mass % based on the mass of the entire iron-based catalyst body when the amount of the iron component contained in the iron-based catalyst body is converted into the amount of iron oxide.

[0047] The additive metal includes at least one selected from alkali metals. For example, the additive metal preferably includes at least one selected from the group consisting of sodium, potassium, and cesium. Of course, the additive metal may include two or more types. When the additive metal includes sodium, potassium, or cesium, liquid hydrocarbons can be produced more efficiently.

[0048] The content of the added metal in the iron-based catalyst body is preferably 0.2 to 40 mass%, more preferably 0.5 to 20 mass%, based on the amount of the portion of the iron-based catalyst body other than the added metal. When the added metal contains sodium, the content of sodium in the iron-based catalyst body is preferably 0.2 to 20 mass%, more preferably 0.5 to 10 mass%. When the added metal contains potassium, the content of potassium in the iron-based catalyst body is preferably 0.2 to 40 mass%, more preferably 0.5 to 20 mass%. When the added metal contains cesium, the content of cesium in the iron-based catalyst body is preferably 0.2 to 20 mass%, more preferably 0.5 to 10 mass%. When the content of the added metal is within the above range, the conversion rate of carbon monoxide to hydrocarbons tends to be further improved.

[0049] The iron-based catalyst is, for example, Fe 3+ The iron(III) oxide-containing powder can be obtained by a method comprising the steps of generating a precipitate of a hydroxide containing trivalent iron from an aqueous solution containing the iron(III) oxide, calcining the precipitate to form a powder containing ferric oxide, mixing the powder with an aqueous solution containing the additive metal, and then drying the aqueous solution containing the additive metal.

[0050] The powder containing ferric oxide may be further molded to form a granular compact. Examples of methods for molding the powder include extrusion and tablet molding. A mixture containing the powder of the calcined body and carbon black may also be molded to obtain a compact.

[0051] Each catalyst may be heated during the reaction of producing hydrocarbons from the raw material gas. The heating temperature for the reaction is, for example, 200 to 400° C. The raw material gas may contain only carbon dioxide or carbon monoxide, or may be a mixed gas containing carbon dioxide and carbon monoxide. EXAMPLES

[0052] The present invention will be described in more detail below with reference to examples, although the present invention is not limited to these examples.

[0053] Example 1 [Preparation of copper-based catalyst: reverse shift catalyst] 5.0 g of γ-alumina (Sumitomo Chemical Co., Ltd., BK-105) was suspended in 1.0 L of pure water by stirring with a homomixer. 300 mL of an aqueous solution containing 31.7 g of copper nitrate hydrate (Nacalai Reagent Co., Ltd.) and 38.1 g of zinc nitrate hydrate (Nacalai Reagent Co., Ltd.) was quickly added to the formed suspension at room temperature, and the suspension was then stirred for another hour at room temperature. Thereafter, while continuing stirring with the homomixer, 300 mL of an aqueous solution containing 35.0 g of sodium carbonate (Fujifilm Wako Pure Chemical Industries, Ltd.) was dripped at a drip rate of 5 mL / min at room temperature using a roller pump. The suspension containing the precipitate formed by the dripping was left to stand at 35°C for 24 hours to mature. The supernatant was removed from the suspension after maturation by decanting, and the remaining precipitate was diluted again with water. This decanting and diluting operation was repeated four times.

[0054] Thereafter, the precipitate was taken out by suction filtration, suspended again in pure water, and then the precipitate was taken out by suction filtration. This operation was repeated four times. The precipitate was thoroughly washed with water by this operation. The obtained precipitate was dried by heating at 120°C for 24 hours. The dried precipitate was fired by heating in air circulation at 150°C for 1 hour, 200°C for 1 hour, 250°C for 1 hour, 300°C for 1 hour, 350°C for 1 hour, and 400°C for 4 hours. The firing produced a black powder, which was a copper-based catalyst body containing a copper component and zinc oxide. The black powder was pulverized in a mortar and the fine powder was molded at a pressure of 40 MPa to produce a copper-based catalyst body, which was a cylindrical molded body with a diameter of 3 mm and a height of 3 mm.

[0055] [Preparation of iron-based catalyst: FT catalyst 24a] 146.9 g of iron nitrate nonahydrate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was dissolved in 120 mL of pure water with stirring at 70°C to prepare a solution with an iron ion concentration of 3 mol / L. Sodium hydroxide solution (16.6 mol / L) prepared by dissolving 47.9 g of sodium hydroxide in 70 mL of pure water was added dropwise to the solution so that the pH of the solution became 11 to 12, producing a solution containing a precipitate of iron (III) hydroxide (Fe(OH)3). The precipitate contained in this solution was filtered using a vacuum pump, and the filtrate obtained was repeatedly washed so that the amount of alkali metal was below a specified amount. The reason for this is that if a large amount of alkali metal (unspecified amount) remains, it becomes difficult to adjust the amount of alkali metal to be supported on the ferric oxide carrier in the subsequent alkali metal addition process.

[0056] The precipitate was then dried by heating at 120°C for 12 to 20 hours. The dried precipitate was calcined by finally heating at 400°C for 5 hours while increasing the ambient temperature at a rate of 5°C / min under air flow. As a result, 28.7 g of ferric oxide (Fe2O3) was obtained.

[0057] Next, 5 g of the obtained ferric oxide was dissolved in an aqueous sodium hydroxide solution or an aqueous sodium nitrate solution, dried at 120°C for 12 to 20 hours, and finally calcined by heating at 400°C for 5 hours while increasing the atmospheric temperature at a heating rate of 5°C / min under air flow. This results in a powder of an iron-based catalyst body containing a support mainly composed of ferric oxide and an alkali metal supported on the support. When ferric oxide is dissolved in an aqueous sodium hydroxide solution, the calcination step may be omitted and only the drying step may be performed. The powder is then molded to obtain a molded body of a predetermined shape. The iron-based catalyst body in each of the following examples is in the form of flakes having a diameter of 2 to 3 mm.

[0058] When potassium is to be supported on ferric oxide as an alkali metal, an aqueous solution of potassium hydroxide or potassium nitrate may be used, and when cesium is to be supported on ferric oxide as an alkali metal, an aqueous solution of cesium hydroxide or cesium nitrate may be used.

[0059] [Preparation of cobalt-based catalyst: FT catalyst 24a] 1.23 g of cobalt nitrate hexahydrate was dissolved in 1.50 g of pure water. The obtained aqueous solution was impregnated into 4 g of spherical alumina (KHA-24, manufactured by Sumitomo Chemical Co., Ltd.) and dried overnight at 110° C. This impregnation and drying was repeated twice to obtain a cobalt-based catalyst (Al-supported Co-based catalyst) in which 12.5 mass % of cobalt was supported on the alumina carrier.

[0060] [Reduction treatment of each catalyst] Each catalyst was packed in a fixed-bed reaction tube with an inner diameter of 1.27 cm, and arranged in the order of copper-based catalyst, iron-based catalyst, and cobalt-based catalyst from the gas inlet side (upstream side) of the reaction tube. Then, under atmospheric pressure, a flow gas consisting of 1% by volume of hydrogen and nitrogen was circulated in the reaction tube at a flow rate of 200 Ncc / min, and the temperature of the catalyst was raised from room temperature to 150°C over 1 hour. While maintaining at 150°C, the concentration of hydrogen contained in the flow gas was changed in the order of 2% by volume, 10% by volume, 20% by volume, 50% by volume, and 100% by volume. After changing to a flow gas (hydrogen gas) with a hydrogen concentration of 100% by volume, the flow state was maintained for 2 hours. Thereafter, while continuing the flow of hydrogen gas, the temperature of the catalyst was raised to 350°C at a rate of 200°C / hour, and the catalyst was reduced by maintaining it at 350°C for 7 hours.

[0061] Example 2 [Preparation of iron-based catalyst: FT catalyst 24a] In Example 2, triiron tetroxide (Fe3O4) was prepared as a support for an iron-based catalyst. 15.8 g of iron trichloride hexahydrate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) and 6.3 g of iron dichloride tetrahydrate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) were dissolved in a mixed solution of 75 mL of pure water and 2.5 mL of 35% hydrochloric acid while stirring at 60°C. 336 mL of 5% ammonia water was added dropwise to the dissolved solution while keeping the temperature at 60°C, and then the solution was stirred for 1 hour. A precipitate was formed in the solution. The supernatant was removed by decanting, and the remaining precipitate was filtered while being washed with 400 mL of pure water. The obtained precipitate was dried by heating at 70°C for 6 hours. The obtained black powder was pulverized in a mortar. The fine powder was molded at a pressure of 40 MPa to obtain a cylindrical molded body containing Fe3O4 with a diameter of 2 mm and a height of 2 mm. 10 g of this compact was impregnated with an aqueous solution containing 0.17 g of sodium hydroxide (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) and 4.63 g of pure water, and the aqueous solution impregnated in the compact was dried by heating at 60°C for 18 hours to obtain an iron-based catalyst compact containing an iron-based catalyst (NaFe3O4). The ratio of sodium to Fe3O4 was calculated to be about 1 mass%.

[0062] Example 3 [Preparation of iron-copper catalyst: FT catalyst 24a] In Example 3, an iron-copper catalyst was prepared as a catalyst containing iron. 34.6 g of iron nitrate nonahydrate and 2.3 g of copper nitrate trihydrate were dissolved in distilled water to prepare a solution with a total volume of 100 mL. Then, while maintaining the temperature at 70°C, 5% ammonia water was added dropwise until the pH became 8. The amount of the drop was 212 mL. The solution was further stirred at room temperature for 15 hours, and the resulting precipitate was removed by filtration and washed with distilled water. The precipitate was dried by heating at 120°C for 6 hours. 8 g of the obtained powder was impregnated with an aqueous solution containing 0.55 g of sodium hydroxide (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) and 3 g of pure water, and dried at 60°C for 18 hours. The powder was then calcined at 350°C for 3 hours to obtain an iron-copper catalyst containing iron, copper and sodium. The ratio of sodium to the iron-copper catalyst was calculated to be about 4 mass%.

[0063] Although the present invention has been described above with reference to the above-mentioned embodiments and examples, the present invention is not limited to the above-mentioned embodiments and examples, and suitable combinations or substitutions of the configurations of the embodiments and examples are also included in the present invention. Furthermore, it is possible to suitably rearrange the combinations and processing orders in the embodiments and examples based on the knowledge of a person skilled in the art, and to make modifications such as various design changes to the embodiments, and the embodiments to which such modifications have been made are also included in the scope of the present invention. [Explanation of symbols]

[0064] 10 catalyst system, 12 reverse shift reactor, 14 FT reactor, 20 reactor, 20a inlet, 20b outlet, 22 reactor, 22a reaction tube, 24 catalyst section, 24a FT catalyst, 26 space, 32 reactor, 32a reaction tube, 40 reactor, 42 heat dissipation mechanism, 42a heat dissipation fin, 50 reactor, 52 heat dissipation mechanism.

Claims

1. A reactor in which a plurality of cylindrical reaction tubes are arranged in parallel; a catalyst section filled inside the reaction tube and including a catalyst for producing hydrocarbons by a reaction using carbon monoxide and hydrogen by an FT method, a difference between a gas temperature before the carbon monoxide-containing gas flows into the reaction tube and a temperature of a high-temperature region which becomes the highest temperature in the catalyst section when hydrocarbons are produced is set to 30° C. or less, The reaction tube has a cross-sectional area that is the same from the upstream side to the downstream side, The catalyst section is a reaction apparatus in which the catalyst is filled in the reaction tubes such that a filling amount of the catalyst filled in an upstream half of the reaction tubes is 50 to 90 mass % of a filling amount of the catalyst filled in a downstream half of the reaction tubes.

2. The reaction tubes include a first reactor tube packed with a first amount of said catalyst; a second reactor tube packed with a second amount of the catalyst, the second amount being different from the first amount; having 2. The reaction apparatus according to claim 1, wherein the first reaction tube and the second reaction tube are arranged in parallel.

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