JP5988243B2 - Hydrocarbon production method - Google Patents

Description

  The present invention relates to an improvement in a method for producing hydrocarbons by reacting carbon dioxide with hydrogen.

  Petroleum or natural gas hydrocarbons that are gaseous at normal temperature and normal pressure are called light hydrocarbons, and those whose main components are propane and butane are compressed or cooled to form a liquid at the same time. Also called liquefied petroleum gas (LPG). LPG is widely used as a household and commercial fuel because it is highly portable and relatively easy to store and supply. Light hydrocarbons such as LPG are separated from natural gas and crude oil, or recovered as a by-product of the oil refining process, but responding to increasing demand for LPG, effective use of coal and carbon-containing waste, etc. From this point of view, methods for synthesizing hydrocarbons using other carbon sources as raw materials have been studied.

  Fischer-Tropsch reaction is widely known as a method for producing hydrocarbons by reacting carbon monoxide with hydrogen in the presence of a catalyst. Also known is a method for producing a hydrocarbon by synthesizing it by further hydrogenating methanol obtained by the reaction of carbon monoxide or carbon dioxide with hydrogen.

A process for synthesizing methanol from a mixed gas of carbon monoxide, carbon dioxide and hydrogen by a gas phase reaction has been put into practical use (see, for example, Non-Patent Document 1), and the reaction formulas are the following formulas (1) and (2). It is represented by
CO + 2H ₂ = CH ₃ OH + 21.6 kcal (1)
CO ₂ + 3H ₂ = CH ₃ OH + H ₂ O + 11.8 kcal (2)
Since the reactions represented by the above formulas (1) and (2) are both exothermic reactions accompanied by a volume reduction, it is necessary to increase the pressure and decrease the temperature in order to increase the reaction reachability. . However, since the reaction rate decreases when the reaction temperature is lowered, these reactions are carried out in the presence of a catalyst. A practical methanol synthesis catalyst in the gas phase synthesis method includes a copper-zinc catalyst. The activation temperature of the zinc oxide-based catalyst is about 400 ° C., but since the rate of change of equilibrium is low at this temperature, it is used under a very high pressure (several tens of MPa). Copper-based catalysts have high activity and are used at 250 to 300 ° C. and 5 to 15 MPa.

  Further, a methanol synthesis method by a liquid phase method has been proposed as a process replacing the gas phase method using the reactions of the above formulas (1) and (2) (see, for example, Patent Documents 1 to 3).

JP-A-6-263666 JP-A-9-187654 JP 2008-19176 A

“Survey on Energy Conversion Technology Using Biomass Resources (III)”, New Energy and Industrial Technology Development Organization, 2000 Survey Report, NEDO-GET-0004, March 2001

  However, the method described in Non-Patent Document 1 requires a high temperature and pressure of 5 to 15 MPa. For this reason, there is a problem that the reaction equipment becomes large and energy for pressurization is required. In addition, the equilibrium conversion rate is limited, and there is a problem that the conversion rate per pass is low. Furthermore, the removal of heat to prevent catalyst deterioration has become a problem. Moreover, the water produced | generated with the methanol and hydrocarbon which are target products by reaction of Formula (2), or hydrogenation reaction of methanol also causes deterioration of a copper-zinc type methanol synthesis catalyst.

  The methods described in Patent Documents 1 and 2 still have the above-mentioned problem similar to the method described in Non-Patent Document 1 in that a high pressure is required in spite of being a liquid phase method. Further, as a problem common to the liquid phase method, a large amount of solvent is required, or the reaction liquid mixed with the catalyst becomes a slurry, and in any case, the reaction rate is lowered.

  Various methods for synthesizing hydrocarbons from carbon monoxide or a mixture of carbon monoxide and carbon dioxide and hydrogen have been proposed, but there are proposals for methods for synthesizing hydrocarbons using only carbon dioxide as a carbon source. The current situation is that nothing has been done.

  The present invention has been made in view of such circumstances, and provides a hydrocarbon production method that can be carried out at a temperature and pressure lower than those of conventional methods and that can produce hydrocarbons from carbon dioxide and hydrogen with high efficiency. The purpose is to do.

The present invention that meets the above-mentioned object solves the above-mentioned problems by providing a method for producing hydrocarbons according to any one of the following [1] to [4].
[1] A method for producing a hydrocarbon having 1 to 9 carbon atoms by reacting carbon dioxide and hydrogen,
A methanol synthesis catalyst having a particle size of 0.1 to 5 mm as a main component, a copper-zinc-alumina mixed oxide, and catalyzing a reaction of synthesizing methanol from carbon dioxide and hydrogen ;
A zeolite catalyst having a particle size of 0.1 to 5 mm , in which one or more metals selected from palladium, nickel, and copper are supported on zeolite, and catalyzing the reaction in which hydrocarbons and water are produced from methanol and hydrogen. To mixed catalyst mixed with hydrocarbon synthesis catalyst,
A gaseous raw material mixture containing carbon dioxide, hydrogen and a straight-chain paraffinic hydrocarbon having 9 or less carbon atoms is brought into contact under conditions of a reaction temperature of 250 to 350 ° C. and a reaction pressure of 0.1 to 5 MPa,
Production of hydrocarbon having a step of producing a hydrocarbon by reacting gas phase with carbon dioxide and hydrogen in a state where the methanol synthesis catalyst in the mixed catalyst is covered with the linear paraffinic hydrocarbon in the raw material mixture Way .
[ 2 ] The method for producing a hydrocarbon according to the above [1] , wherein a weight ratio of the methanol synthesis catalyst to the hydrocarbon synthesis catalyst in the mixed catalyst is 1: 2 to 2: 1.
[ 3 ] The method for producing a hydrocarbon according to the above [1] or [2 ], wherein the linear paraffinic hydrocarbon is n-hexane.
[ 4 ] The method for producing a hydrocarbon according to any one of [ 1 ] to [ 3 ], wherein the zeolite is zeolite ZSM-5 or β-zeolite.

In the hydrocarbon production method of the present invention, since a copper-zinc based methanol synthesis catalyst and a zeolite catalyst are mixed and used, the methanol produced by the reaction of carbon dioxide and hydrogen is rapidly hydrogenated by the action of the zeolite catalyst. Converts to a receiving hydrocarbon. Therefore, the equilibrium of the reaction of the above formula (2) can be shifted to the product side without lowering the temperature or increasing the pressure more than necessary. Therefore, according to the method for producing hydrocarbons of the present invention, it becomes possible to produce light hydrocarbons that can be used at low cost and in the same manner as liquefied petroleum gas and gasoline using carbon dioxide as a raw material. In addition, by bringing linear paraffinic hydrocarbons into contact with the mixed catalyst together with carbon dioxide and hydrogen as raw materials, the surface of the copper-zinc methanol synthesis catalyst is coated with a hydrophobic film made of linear paraffinic hydrocarbons. The reaction can be catalyzed in a wet state. Thereby, since the water produced | generated by reaction of a carbon dioxide and hydrogen cannot contact a methanol synthesis catalyst, the deactivation of the methanol synthesis catalyst by water can be prevented. In addition, by using a mixed catalyst in which a methanol synthesis catalyst having a predetermined particle size and a zeolite catalyst are mixed, the zeolite catalyst and the methanol synthesis catalyst are separated by a hydrophobic film formed on the latter surface. An appropriate distance can be maintained in the state. Therefore, the deactivation of the methanol synthesis catalyst by water generated during the hydrogenation reaction of methanol on the zeolite catalyst can also be prevented. Therefore, according to the method for producing hydrocarbons of the present invention, hydrocarbon production can be carried out stably and efficiently over a long period of time without a decrease in catalytic activity during the reaction. Furthermore, the method for producing hydrocarbons of the present invention is produced by burning fossil fuels from factories, power plants, etc., and makes it possible to produce hydrocarbons using carbon dioxide that can be obtained at low cost as a raw material. In addition to being low-cost, it is a method that can contribute to the reduction of emissions of carbon dioxide, which is a greenhouse gas, and thus to the reduction of environmental impact. In particular, when carbon dioxide generated by combustion of biomass fuel is used as a carbon dioxide raw material, the method of the present invention is a low-cost and energy-efficient biomass utilization technology compared to biomass utilization technology such as biomass gasification. It is also what provides.

It is a schematic diagram which shows an example of the apparatus used for the manufacturing method of hydrocarbon. 2 is a graph showing changes over time in the conversion rate of carbon dioxide and the selectivity of carbon monoxide in Example 1. FIG. 2 is a graph showing the carbon number distribution in the generated hydrocarbon in Example 1. FIG. 4 is a graph showing changes over time in the conversion rate of carbon dioxide and the selectivity of carbon monoxide in Example 2. FIG. 6 is a graph showing the carbon number distribution in the generated hydrocarbon in Example 2. 6 is a graph showing changes over time in carbon dioxide conversion and carbon monoxide selectivity in Example 3. FIG. 6 is a graph showing a carbon number distribution in a generated hydrocarbon in Example 3. 6 is a graph showing changes over time in the conversion rate of carbon dioxide and the selectivity of carbon monoxide in Comparative Example 1; 6 is a graph showing changes over time in the conversion rate of carbon dioxide and the selectivity of carbon monoxide in Comparative Example 2.

  Next, embodiments of the present invention will be described with reference to the accompanying drawings for understanding of the present invention.

A hydrocarbon production method according to an embodiment of the present invention (hereinafter, may be abbreviated as “hydrocarbon production method” or “this method” in some cases) is obtained by reacting carbon dioxide with hydrogen. A method for producing 1 to 9 hydrocarbons, wherein a methanol synthesis catalyst having a particle size of 0.1 to 5 mm and a hydrocarbon synthesis catalyst having a particle size of 0.1 to 5 mm are mixed with a mixed catalyst. Methanol in the mixed catalyst is brought into contact with a gaseous raw material mixture containing carbon, hydrogen and a straight-chain paraffinic hydrocarbon having 9 or less carbon atoms under the conditions of a reaction temperature of 250 to 350 ° C. and a reaction pressure of 0.1 to 5 MPa. It has a step of producing a hydrocarbon by subjecting carbon dioxide and hydrogen to a gas phase reaction in a state where the synthesis catalyst is covered with the straight-chain paraffinic hydrocarbon in the raw material mixture.

<1> Mixed catalyst The mixed catalyst used in this method is a mixture of a methanol synthesis catalyst having a particle size of 0.1 to 5 mm and a hydrocarbon synthesis catalyst having a particle size of 0.1 to 5 mm. The particle sizes of the methanol synthesis catalyst and the hydrocarbon synthesis catalyst are both 0.1 to 5 mm, preferably 0.5 to 2 mm. When the particle size of both exceeds 5 mm, the surface area per unit volume becomes small, so that the catalyst efficiency decreases. In addition, if the particle size of both is less than 0.1 mm, the distance between the reaction sites of the methanol synthesis catalyst and the hydrocarbon synthesis catalyst becomes too close, and the former is lost due to water generated in the methanol hydrogenation reaction catalyzed by the latter. It becomes easy to receive life. For the same reason, it is not preferable to pulverize the raw material mixture of the methanol synthesis catalyst and the hydrocarbon synthesis catalyst or to support one on the other when preparing the mixed catalyst.

The methanol synthesis catalyst refers to any catalyst that catalyzes the reaction of synthesizing methanol from carbon dioxide and hydrogen by the reaction of the following formula (2).
CO ₂ + 3H ₂ = CH ₃ OH + H ₂ O + 11.8 kcal (2)
Examples of the methanol synthesis catalyst include a copper-zinc catalyst, a palladium-zinc-chromium catalyst, a zinc-chromium catalyst, a palladium catalyst, and the like, preferably a copper-zinc catalyst. As the copper-zinc-based methanol synthesis catalyst, any catalyst containing a composite oxide containing copper and zinc as a main component can be used. As a specific example, a copper-zinc-alumina mixed oxide is used as a main component. And the like. These catalysts may be commercially available or may be synthesized using any known method.

  The hydrocarbon synthesis catalyst refers to any catalyst that catalyzes a reaction in which hydrocarbon and water are produced from methanol and hydrogen. Examples of the hydrocarbon synthesis catalyst include zeolite, but a metal-supported zeolite (zeolite catalyst) on which one or more metals selected from palladium, nickel and copper are supported is particularly preferable. When a zeolite that does not carry metal is used as a catalyst, the production rate of olefins increases, and this polymerizes and precipitates around the mixed catalyst, and further undergoes thermal decomposition to carbonize, so it is the target. This causes a decrease in the production rate of hydrocarbons having 1 to 9 carbon atoms and a decrease in catalyst activity. Therefore, the above metal is supported to improve the production rate of paraffinic hydrocarbons. Any zeolite can be used without particular limitation. Specific examples include ZSM-5, β-zeolite, SAPO, mordenite, Y-type zeolite, USY, etc. By selecting one, the number of carbon atoms of the synthesized hydrocarbon and its distribution can be controlled. Particularly preferred zeolites are ZSM-5 and β-zeolite. Zeolites may be commercially available or may be synthesized using any known method.

  The metal can be supported, for example, by immersing the zeolite powder in an aqueous solution of a metal salt or complex to be supported, impregnating the zeolite with the solution, and drying. The amount of metal supported is preferably 0.1% by weight or more. The upper limit of the supported amount is not particularly limited, but is usually 1% by weight or less, preferably 0.5% by weight or less.

  These catalysts are prepared separately, adjusted to a predetermined particle size as necessary, and then mixed to obtain a mixed catalyst. The mixing ratio of the methanol synthesis catalyst and the hydrocarbon synthesis catalyst is not particularly limited, but the weight ratio of the two is preferably in the range of 1: 4 to 4: 1, and is in the range of 1: 2 to 2: 1. It is more preferable. The mixed catalyst may be used as a powder, but may be formed into a granular shape or a pellet shape having a predetermined size and shape, or may be used in a state of being applied to the surface of a heat exchanger or a reactor. Good. The mixing and shaping of both catalysts can be performed using any method as long as the particle size of both catalysts is not deviated from the above range, but a dry method is preferably used. Specific examples of the method for forming the mixed catalyst include an extrusion molding method and a tableting molding method.

The mixed catalyst may contain other components as long as the effect is not impaired. Specific examples of other components include inert and stable heat conductors such as silica and alumina.
In addition, if necessary, the reduction treatment may be performed using any known method such as heating in a reducing atmosphere such as hydrogen. The preprocessing may be performed.

<2> Reaction conditions The above catalyst is brought into contact with a gaseous raw material mixture containing carbon dioxide, hydrogen, and a linear paraffinic hydrocarbon having 9 or less carbon atoms, and carbon dioxide and hydrogen are reacted in the gas phase. A hydrocarbon having 1 to 9 carbon atoms is obtained. The method of the catalyst bed is not particularly limited, and any method such as a fixed bed, a boiling bed, a fluidized bed, and a moving bed can be used. The origin of carbon dioxide used as a raw material is not particularly limited. Specific examples of the carbon dioxide source include high-concentration carbon dioxide, which can be used at low cost and in large quantities for thermal power plant exhaust gas, and ironworks blast furnace gas. And chemical plants. The origin of hydrogen used as a raw material is not particularly limited, but it may be produced by a method such as electrolysis of water, including high-concentration hydrogen, coke oven gas such as steelworks that can be used in large quantities at low cost. Hydrogen may be used. From the viewpoint of reducing the environmental load and saving energy, the electricity used for water electrolysis is preferably generated using natural energy such as solar power generation or wind power generation or renewable energy.

It is preferable that carbon dioxide and hydrogen as raw materials are mixed with linear paraffinic hydrocarbons, and then the gaseous raw material mixture is adjusted to a predetermined pressure and temperature and brought into contact with the catalyst. The raw material mixture may contain an inert gas such as nitrogen or argon as necessary for adjusting the partial pressure and thermal conductivity of each raw material. An example of a reaction apparatus that can be used for carrying out this method is shown in FIG. The meanings of the abbreviations in FIG. 1 are as follows.
FIC: Flow controller with flowmeter PIC: Pressure controller with pressure gauge TIC: Temperature controller with thermometer PI: Pressure gauge TI: Thermometer GC: Gas chromatograph Note that linear paraffinic hydrocarbons are liquid at normal temperature and normal pressure In this case, it is introduced into the reactor via a high-pressure pump and vaporized inside. The partial pressure of the linear paraffinic hydrocarbon is controlled by adjusting the flow rate of the pump.

The overall reaction formula of this method is represented by the following formula (3).
nCO ₂ + (3n + 1) H ₂ → C _n H _{2n + 2} + 2nH ₂ O (3)
Therefore, the theoretical molar ratio of carbon dioxide and hydrogen in the raw material mixture is 1: (3 + 1 / n). Accordingly, the molar ratio of carbon dioxide to hydrogen is adjusted to an appropriate value exceeding 1: 3 and not more than 1: 4.

The molar ratio of the straight-chain paraffinic hydrocarbon to the raw material gas (carbon dioxide + hydrogen) is preferably 1: 4 to 4: 1, more preferably 1: 2 to 2: 1. The linear paraffinic hydrocarbon is adsorbed on the surface of the methanol synthesis catalyst in the reaction tank to form a hydrophobic film covering the surface, and transfers reaction heat generated in or on the catalyst to the surroundings. It can also act as a heat medium. The number of carbon atoms of the linear paraffinic hydrocarbon is preferably 4 or more and 8 or less, and particularly preferably 5 or 6. Particularly preferred linear paraffinic hydrocarbon includes n-hexane. Under the reaction conditions, n-hexane is considered to form a subcritical coating, which inhibits contact of water with the methanol synthesis catalyst surface without inhibiting reaction gas contact with the catalyst surface, Deterioration of catalyst performance can be prevented. In addition, you may utilize at least one part of the linear paraffinic hydrocarbon which satisfy | fills the said conditions among the hydrocarbons manufactured by this method as a linear paraffinic hydrocarbon mixed with source gas .

Although the temperature (reaction temperature) of the raw material mixture immediately before contacting the catalyst bed is not particularly limited as long as the reaction proceeds smoothly, it is preferably, for example, 250 ° C. or higher. The upper limit of the reaction temperature is, for example, 350 ° C. The pressure of the raw material mixture immediately before contacting the catalyst bed is 0.1 to 5 MPa, preferably 0.4 to 4 MPa.

  The flow rate of the raw material mixture is preferably 10 to 100 mL / min per 1 g of catalyst, and more preferably 20 to 50 mL / min.

  The hydrocarbon thus obtained contains a linear or branched hydrocarbon having 1 to 9 carbon atoms. The number of hydrocarbons and their distribution vary depending on the hydrocarbon synthesis catalyst (zeolite type and supported metal) in the mixed catalyst used, reaction conditions (temperature, pressure, flow rate of the raw material mixture), etc. Typically, hydrocarbons having 3 and 4 carbon atoms (propane and butane) are contained in an amount of about 50% by weight, but not limited thereto.

  Hydrocarbons can be used for liquefied petroleum gas or gasoline (fuel etc.) depending on the number of carbons. The hydrocarbons may be used as they are, but if necessary, they may be used after separation and purification or isomerization by any known means such as distillation.

Next, examples carried out for confirming the effects of the present invention will be described.
Using the apparatus shown in FIG. 1, a vaporized raw material mixture of carbon dioxide, hydrogen, n-hexane and argon (inner standard) (the molar ratio and total pressure of each component were adjusted by the pressure of each component) The mixture was heated to a predetermined temperature and brought into contact with a mixed catalyst in a reaction tube installed in an electric furnace to produce hydrocarbons.

1. Preparation of mixed catalyst (1) Methanol synthesis catalyst A copper / zinc / alumina catalyst was used as the methanol synthesis catalyst. Using a tablet molding machine, a powdery methanol synthesis catalyst was formed into a disk shape (40 kg / cm ³ , 30 seconds) and then crushed to 0.37 to 0.84 mm.

(2) Hydrocarbon synthesis catalyst As a hydrocarbon synthesis catalyst, ZSM-5 (Zeolyst (USA), supported by 0.5% by weight of palladium (Pd), having a SiO ₂ / Al ₂ O ₃ molar ratio of 23 )It was used. Palladium was supported using the following ion exchange method. An aqueous solution of Pd (NH ₃ ) ₄ Cl ₂ (6 mg Pd / mL) was prepared and diluted to 100 mL. The amount of solution required to support 0.5% by weight of palladium was weighed into a container, diluted with ion-exchanged water (25 mL), 3 g of ZSM-5 was added, and the resulting suspension was added from 60 to 60%. Stir at 70 ° C. for 8 hours. The suspension was filtered and washed with ion-exchanged water until no chloride ions were detected in the washing solution. Subsequently, after drying at 120 degreeC for 12 hours, it sintered at 500 degreeC for 2 hours, and obtained the powdery hydrocarbon synthesis catalyst. Using a tablet molding machine, the powdered hydrocarbon synthesis catalyst was formed into a disk shape (40 kg / cm ³ , 30 seconds) and then crushed to 0.37 to 0.84 mm.

(3) Preparation and pretreatment of mixed catalyst The methanol synthesis catalyst and hydrocarbon synthesis catalyst obtained as described above were mixed at a weight ratio of 1: 1 to obtain a mixed catalyst. This was filled into a fixed bed pressurized flow type reaction tube (inner diameter 6 mm, total length 30 cm) (filled in the order of glass wool, glass beads, catalyst, and glass beads), and 2 at 250 ° C. under a nitrogen stream (100 mL / min). Dry for hours. Subsequently, reduction treatment was performed by heating at 300 ° C. for 3 hours while flowing high purity hydrogen / nitrogen = 5/95 (100 mL / min).

  The molar ratio of carbon dioxide and hydrogen in the gas mixture was 1: 3, and the molar ratio of carbon dioxide + hydrogen and n-hexane was 1: 1 or 1: 1.75. For comparison, the case where n-hexane was not added was also examined. The flow rate of the reaction mixture was 21 mL / min or 42 mL / min per 1 g of the mixed catalyst, and the pressure was 3 MPa or 4 MPa. The temperature of the reaction mixture immediately before contacting the mixed catalyst was adjusted to 280 ° C.

The mixture after the reaction is cooled by a cooler installed downstream during the reaction, and the added n-hexane and the generated hydrocarbons having high boiling points are liquefied here and periodically analyzed offline. (FID gas chromatograph, GC-8A manufactured by Shimadzu Corporation, TC-1 column manufactured by GL Sciences Inc. (inner diameter 0.25 mm × length 30 m, film thickness 1.00 μm), column temperature 60 to 230 ° C.). On the other hand, low boiling point components that do not liquefy even in the cooler are FID (hydrocarbon) or TCD (carbon monoxide, carbon dioxide, methane, and argon) gas chromatograph (gas chromatograph, GC-8A manufactured by Shimadzu Corporation) installed on the flow path. InterCap manufactured by GL Sciences Inc.
One column (inner diameter 0.25 mm × length 30 m, film thickness 1.50 μm) was used. Column temperature was analyzed using 60-230 ° C. (for FID) or 100 ° C. (for TCD)).

  After reducing the mixed catalyst set in the reaction tube by the above procedure, the temperature of the reactor was once returned to room temperature and nitrogen and hydrogen gas were stopped. Next, the pressure was raised to a predetermined pressure while flowing the reaction mixture, and then the temperature was raised to a predetermined temperature, and then the reaction was started. The product was periodically sampled and analyzed downstream of the cooler.

  Table 1 shows the molar ratio of carbon dioxide + hydrogen and n-hexane, the flow rate of the reaction mixture per 1 g of the mixed catalyst, and the pressure in each Example and Comparative Example.

  2, 4, 6, 8, and 9 show graphs showing changes over time in the conversion rate of carbon dioxide and the selectivity of carbon monoxide in the examples and comparative examples, respectively. Moreover, the graph which shows carbon number distribution in hydrocarbon in each Example is shown to FIG. In addition, the selectivity of carbon monoxide in FIGS. 2, 4, 6, 8, and 9 refers to the ratio of carbon monoxide generated by the water gas reverse shift reaction to the reaction product of carbon dioxide. 3, 5, and 7, as for the ratio of normal paraffin (n-hexane) having 6 carbon atoms, n-hexane added to the reaction mixture is also detected at the same time. And the average value of the proportion of n-heptane.

  As is apparent from a comparison between FIGS. 8 and 9 (Comparative Examples 1 and 2) and FIGS. 2, 4 and 6 (Examples 1, 2 and 3), when the reaction mixture does not contain n-hexane, the time As time passes, the conversion rate of carbon dioxide decreases, and the selectivity of carbon monoxide increases rapidly. This is considered to be due to the fact that the methanol synthesis catalyst is deactivated by the influence of water due to the reaction and the water gas reverse shift reaction becomes dominant. On the other hand, in any of Examples 1, 2, and 3, the carbon monoxide selectivity was 30% or less, and the carbon dioxide conversion rate also maintained a value of 30% or more. From these results, it was confirmed that by adding n-hexane to the reaction mixture, deactivation of the methanol synthesis catalyst can be suppressed, and hydrocarbons can be produced in a high yield over a long period of time.

  Moreover, it was confirmed from the comparison of Example 2 and 3 that the conversion rate of a carbon dioxide improves by reducing the flow volume of a reaction mixture, and the generation rate of a hydrocarbon with a large carbon number increases.

Claims (4)

A method of producing a hydrocarbon having 1 to 9 carbon atoms by reacting carbon dioxide and hydrogen,
A methanol synthesis catalyst having a particle size of 0.1 to 5 mm as a main component, a copper-zinc-alumina mixed oxide, and catalyzing a reaction of synthesizing methanol from carbon dioxide and hydrogen ;
A zeolite catalyst having a particle size of 0.1 to 5 mm , in which one or more metals selected from palladium, nickel, and copper are supported on zeolite, and catalyzing the reaction in which hydrocarbons and water are produced from methanol and hydrogen. To mixed catalyst mixed with hydrocarbon synthesis catalyst,
A gaseous raw material mixture containing carbon dioxide, hydrogen and a straight-chain paraffinic hydrocarbon having 9 or less carbon atoms is brought into contact under conditions of a reaction temperature of 250 to 350 ° C. and a reaction pressure of 0.1 to 5 MPa,
Characterized in that it has a step of producing a hydrocarbon by reacting gas phase with carbon dioxide and hydrogen in a state where the methanol synthesis catalyst in the mixed catalyst is coated with the linear paraffinic hydrocarbon in the raw material mixture. A method for producing hydrocarbons. The weight ratio of the hydrocarbon synthesis catalyst and the methanol synthesis catalyst in the mixed catalyst is from 1: 2 to 2: method for producing hydrocarbons according to claim 1, wherein the 1. The method for producing a hydrocarbon according to claim 1 or 2, wherein the linear paraffinic hydrocarbon is n-hexane. The method for producing hydrocarbons according to any one of claims 1 to 3 , wherein the zeolite is zeolite ZSM-5 or β-zeolite.