JP2014198332A - Catalyst for manufacturing light hydrocarbon from synthetic gas, method for manufacturing the catalyst, and method for manufacturing light hydrocarbon from synthetic gas - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a catalyst unlikely to entail, even if a high productivity is set within a microchannel reactor, haywire consequences and yielding, without being accompanied by flow channel congestions, relatively low selectivities of gas products such as methane, etc.; a method for manufacturing the catalyst; and a method for manufacturing a light hydrocarbon from a synthetic gas by using the catalyst.SOLUTION: The provided catalyst for manufacturing a light hydrocarbon from a synthetic gas has an average particle diameter of 400 μm or less and includes both a catalyst exhibiting an activity for an exothermic reaction of generating a hydrocarbon from a synthetic gas and including a metallic compound exhibiting an activity for a Fischer-Tropsch synthesizing reaction and a catalyst exhibiting an activity for an endothermic reaction of decomposing and lightening the hydrocarbon thus generated.

Description

  The present invention relates to a catalyst for producing light hydrocarbons from so-called synthesis gas containing carbon monoxide and hydrogen as main components, a method for producing the same, and a method for producing light hydrocarbons using the catalyst.

In recent years, environmental problems such as global warming have become apparent, H / C is higher than other hydrocarbon fuels, coal, etc., and carbon dioxide emissions that are the cause of global warming can be suppressed. The importance of natural gas, which is abundant in volume, has been reviewed, and its demand is expected to increase in the future. As a means of natural gas development, after converting natural gas to synthesis gas, as shown in the following reaction formula, the synthesis gas is converted into a Fischer-Tropsch synthesis reaction (hereinafter “FT synthesis reaction”). Gas To Liquids (GTL) technology development is being carried out vigorously at various locations to convert to liquid hydrocarbon fuels such as kerosene and light oil with excellent transportability and handling properties. Sasol and Shell have several A 10,000 BPD-scale commercial plant is in operation. As the catalyst, a catalyst in which cobalt is supported on a porous carrier is generally used, and a catalyst containing various promoters has been developed (see Non-Patent Document 1).

This FT synthesis reaction is an exothermic reaction in which synthesis gas is converted into hydrocarbons using a catalyst, but it is extremely important to effectively remove reaction heat for stable operation of the plant. The reaction formats that have been proven to date include gas phase synthesis processes (fixed bed, spouted bed, fluidized bed) and liquid phase synthesis processes (slurry bed). A fixed floor is adopted. This is because development by these large-scale plants is economical only in large-scale natural gas fields.
Of these large-scale plants, as the catalyst used in the FT synthesis in the fixed bed, generally a large one having an average particle diameter of about 1 to several mm is used. Is usually 10 μm to 10 mm (see paragraph 0010), but in the examples, alumina having a particle size of 10 to 20 mesh (a sieve opening of 0.841 to 2 mm (ASTM)) as a particulate solid which is a skeleton of the catalyst. (Al ₂ O ₃ ) is used (see paragraph 0020).

  By the way, many small-scale gas fields that existed on the earth have been undeveloped until now, but in recent years, such as the development of these small-scale gas fields, the oil-related gas that is currently treated as flare The development of a compact plant that can be installed on an offshore drilling vessel, with the goal of converting liquid hydrocarbon fuel, has been energetically conducted at various locations. Among these, in the FT synthesis reaction process, a technique using a microchannel reactor has been developed. This microchannel reactor is a fine flow path with an inner diameter of several mm or less and is characterized by high mass transfer and heat transfer performance. Also, for the microchannel reactor used in the FT synthesis reaction, for example, As shown in FIG. 7, the material gas flow path for performing the FT synthesis reaction and the flow path of the refrigerant for performing heat removal are alternately stacked in a layered structure, and the direction of supplying the raw material gas for performing the FT synthesis reaction and the heat removal. By using the metal as the reactor material, the heat generated in the reaction process can be removed efficiently and mixing of the source gas and the refrigerant is suppressed. You can also

By the way, in the fixed-bed FT synthesis reaction in a large-scale plant, it is necessary to suppress the calorific value according to the heat removal performance, and it is often necessary to operate with a reduced production amount. The FT synthesis used has high heat removal performance and can be set to high productivity, resulting in high hydrocarbon production per reactor volume. However, when productivity is set high, the heat removal fluid that was initially liquid in the heat removal microchannel becomes a vapor having a small heat capacity, and the heat efficiency in the microchannel in which the vapor flows is high. The heat generated in the microchannel adjacent to this microchannel (the flow path of the raw material gas that performs the FT synthesis reaction) cannot be removed effectively, and then runs away. In addition to excessively increasing the temperature of the catalyst, not only was the FT synthesis reaction inhibited, but the catalyst could be deactivated and its regeneration could be difficult.
In addition, in such an FT synthesis reaction in a microchannel reactor, it is difficult to use a catalyst having a large particle size as used in a large-scale plant, and it is necessary to develop a dedicated catalyst.
Furthermore, in general, the carbon number distribution of the FT synthesis reaction product is supposed to follow the Schulz-Flory rule. In the FT synthesis reaction, in addition to relatively light hydrocarbon compounds that are liquid at room temperature and normal pressure, A relatively heavy hydrocarbon compound (WAX) that is a solid is also produced. Therefore, in the FT synthesis reaction in the microchannel, the reactant passes through a narrow flow path, so when the temperature is lowered when the reaction temperature is low or when the operation is stopped, the flow path is blocked by the generated WAX, Even if there is no channel blockage, the viscosity of the product oil may be high and the handling property may not be good. As a means for avoiding this, the reaction temperature can be set extremely high, but there is a problem that the methane selectivity increases and the yield of the liquid product decreases.

  One way to avoid channel blockage due to WAX is to control the carbon number distribution of the FT synthesis reaction product (by coexisting an FT synthesis catalyst and a catalyst for lightening hydrocarbons) There are reports on catalysts that assume a fixed bed (see Patent Document 1, Non-Patent Documents 2 and 3). These catalysts have been studied with a particle size of several millimeters on the assumption that they are used in large-scale reaction towers, and FT synthesis reactions applied in microchannels were impossible.

JP 2007-197628 A JP 2007-196187 A

R. Oukaci et al., Applied Catalysis A: General, 186 (1999) 129-144 J. He et al., Chemistry A European Journal, 12 (2006) 8296-8304 G. Yang et al., Applied Catalysis A: General, 329 (2007) 99-105

  The present invention relates to a catalyst that contains both a catalyst that promotes a hydrocarbon formation reaction from a synthesis gas that becomes an exothermic reaction, and a catalyst that promotes a reaction that decomposes and lightens the generated hydrocarbon that becomes an endothermic reaction. , Even if the productivity of the FT synthesis reaction is set high in the microchannel reactor, compared to the case of using only a catalyst that produces ordinary hydrocarbons, the runaway heat of the entire system is difficult. , A catalyst for producing light hydrocarbons from synthesis gas, and a method for producing the catalyst, and the catalyst in which the viscosity of the product oil is low and blockage in the flow path can be prevented The present invention provides a method for producing light hydrocarbons.

  The gist of the present invention is as described below.

(1) A catalyst for producing light hydrocarbons from synthesis gas, which contains a metal compound having activity in the Fischer-Tropsch synthesis reaction and produces hydrocarbons from synthesis gas; and the produced hydrocarbons A catalyst for producing light hydrocarbons from synthesis gas, which contains both a catalyst that is decomposed and lightened and has an average particle size of 400 μm or less.
(2) The catalyst for producing light hydrocarbons from the synthesis gas according to (1), wherein the average particle diameter is 200 μm or less.
(3) The catalyst for producing light hydrocarbons from synthesis gas according to (1) or (2), wherein the metal of the metal-based compound contains cobalt.
(4) The light hydrocarbon is produced from the synthesis gas according to any one of (1) to (3), wherein the catalyst for decomposing and lightening the generated hydrocarbon is zeolite. catalyst.
(5) Any one of (1) to (4), wherein a catalyst for decomposing and reducing the generated hydrocarbon is formed on an outer surface of a catalyst for producing hydrocarbons from the synthesis gas. A catalyst for producing light hydrocarbons from the synthesis gas according to claim 1.
(6) The catalyst for producing light hydrocarbons from the synthesis gas according to any one of (1) to (5), wherein the catalyst carrier for producing hydrocarbons from the synthesis gas is silica.
(7) A method for producing the catalyst according to (5) or (6), wherein the silica support is carbonized from a synthesis gas using an impregnation method, an incipient wetness method, a precipitation method, or an ion exchange method. A synthesis characterized in that a catalyst for producing hydrogen is produced, and then a hydrothermal synthesis method is used to form a catalyst for decomposing and reducing the generated hydrocarbons on the outer surface of the produced catalyst. A method for producing a catalyst for producing light hydrocarbons from gas.
(8) A method for producing light hydrocarbons, comprising producing light hydrocarbons from synthesis gas in a microchannel reactor using the catalyst according to any one of (1) to (6).
(9) The process for producing light hydrocarbons according to (8), wherein the flow path width of the microchannel reactor is 4 mm or less.
(10) The method for producing light hydrocarbons according to (8) or (9), wherein the microchannel reactor is formed of a metal material.
(11) The microchannel reactor has a multi-stage layered structure, and includes a layer for supplying synthesis gas to produce light hydrocarbons, and a layer for supplying refrigerant and removing heat generated in light hydrocarbon production. The light hydrocarbon production method according to any one of (8) to (10), wherein the layers are alternately arranged and the flow paths of these layers are arranged in a direction perpendicular to each other.

  According to the present invention, when producing synthetic oil in a microchannel reactor having a flow path width of several millimeters or less, a catalyst that promotes a reaction that decomposes and lightens the generated hydrocarbon that is an endothermic reaction. Because of the coexistence, even if the productivity of the FT synthesis reaction is set high, it is possible to suppress the calorific value of the entire system compared to when only a catalyst for producing ordinary hydrocarbons is used, and the generation It is possible to provide a light hydrocarbon synthesis catalyst having a low oil viscosity and capable of preventing clogging in a flow path, a method for producing the catalyst, and a method for producing light hydrocarbons. Therefore, it is possible to stably carry out hydrocarbon production from small-scale gas fields and petroleum-associated gas that are expected to be developed using a microchannel reactor.

2 is a graph showing the carbon number distribution of the product obtained in Example 1. FIG. It is a figure which shows carbon number distribution of the product obtained in Example 7. It is a figure which shows carbon number distribution of the product obtained in the comparative example 4. It is a figure which shows the cross section of the catalyst which covers the surface of the catalyst which produces | generates a hydrocarbon from synthesis gas, and the catalyst which decomposes | disassembles and lightens a hydrocarbon forms 1 particle | grain. It is a figure which shows the physical mixing of the catalyst which produces | generates a hydrocarbon from a synthesis gas, and the catalyst which decomposes | disassembles and lightens hydrocarbon. It is an image figure when the catalyst is filled in the microchannel and when the catalyst is applied. 1 is a diagram showing a microchannel reactor used in Example 10. FIG.

The present invention is described in further detail below.
When producing synthetic oil (hydrocarbon) from synthesis gas in a microchannel reactor, the present inventors decompose a catalyst that produces hydrocarbons from synthesis gas and the produced hydrocarbons to lighten them. Even if the productivity is set high by using a catalyst with a small particle diameter that contains both catalyst (composite catalyst of a catalyst that generates hydrocarbons from synthesis gas and a catalyst that lightens hydrocarbons) Heat generation is suppressed, and the viscosity of the product oil is low, so it is possible to prevent clogging in the flow path due to WAX generation, and it has a large particle size of several millimeters developed on the premise of a large fixed bed The inventors have found that the methane selectivity is lower than that of the catalyst, and have made the present invention.

  In the catalyst for producing light hydrocarbons from the synthesis gas of the present invention, the coexistence structure of the catalyst for producing hydrocarbons from the synthesis gas and the catalyst for decomposing and reducing the produced hydrocarbons is shown in FIG. As shown in FIG. 4, the latter catalyst covers a part or the entire surface of the former catalyst to form one particle as shown in FIG. In the case of the structure, it does not matter.

  In the case of a structure in which both catalysts are physically mixed, each catalyst particle exists as a separate particle, and in addition to a case in which a plurality of them are mixed, both catalysts are contained in one particle. It may be a structure containing a mixture of A structure in which a mixture of both catalysts is contained in one particle can be produced by using a catalyst having a small particle size and mixing and molding.

  The catalyst for producing hydrocarbons from the synthesis gas according to the present invention is not particularly limited as long as it contains a metal compound active in the FT synthesis reaction, but as its metal species, cobalt, iron, ruthenium, etc. In general, a catalyst containing cobalt is preferable in consideration of performance and price.

  The catalyst carrier of the metal compound can be appropriately selected from porous oxides such as silica, alumina, and titania. Silica and alumina are preferable, and silica is more preferable from the viewpoint of catalytic reaction performance.

  The carrier property of the catalyst for producing hydrocarbons from synthesis gas is not particularly limited, but from the viewpoint of catalytic activity, the dispersibility of the metal compound is kept high, and the efficiency contributing to the reaction of the supported active metal is improved. It is preferable to use a carrier having a high specific surface area. In order to increase the specific surface area, it is necessary to decrease the pore diameter or increase the pore volume.

  However, when the pore diameter is less than 8 nm, the gas diffusion rate in the pore is different between hydrogen and carbon monoxide, and the result is that the hydrogen partial pressure increases as it goes deeper into the pore. Hydrocarbons that are gaseous at normal temperature and normal pressure, such as methane, are undesirable because they generate a large amount. Conversely, if the pore diameter exceeds 50 nm, it is difficult to increase the specific surface area, and active metals This is not preferable because the degree of dispersion of the resin is lowered.

Further, if the pore volume is less than 0.4 cc / g, it is difficult to increase the specific surface area, which is not preferable. The physical properties of the catalyst carrier are preferably those that simultaneously satisfy a pore diameter of 8 to 50 nm, a specific surface area of 80 to 600 m ² / g, and a pore volume of 0.4 to 4 cc / g. More preferably, the pore diameter is 10 to 40 nm, the specific surface area is 100 to 550 m ² / g, and the pore volume is 0.6 to 3.0 cc / g at the same time, and the pore diameter is 12 to 30 nm and the specific surface area is 150 to More preferably, it is 500 m ² / g and the pore volume satisfies 0.8 to 2.0 cc / g at the same time. The specific surface area can be measured by the BET method, and the pore volume can be measured by a mercury intrusion method or a water titration method. The pore diameter can be measured by a mercury adsorption method using a gas adsorption method or a mercury porosimeter, but can also be calculated from the specific surface area and pore volume.

  The supported amount of the metal compound having activity in the FT synthesis reaction on the catalyst carrier is 5 to 50% by mass. For example, when cobalt is used, it is preferably 10 to 40% by mass, more preferably 20 to 35% by mass. If it is below this range, the activity cannot be fully expressed, and if it exceeds this range, the degree of dispersion is lowered, and the utilization efficiency of the supported cobalt is lowered, which is not preferable. The loading rate referred to here means that the metal compound having activity in the supported FT synthesis reaction is not necessarily 100% reduced in the end, but is considered to have been reduced 100% and has activity in the FT synthesis reaction. The ratio of the metal mass in the metal compound to the entire catalyst mass (the entire catalyst mass for producing hydrocarbons from synthesis gas) is indicated.

The supporting method of the metal compound having activity in the FT synthesis reaction on the catalyst carrier may be a normal impregnation method, an incipient wetness method, a precipitation method, an ion exchange method, or the like. The metal compound that is a raw material (precursor) used for loading is a drying treatment after loading, followed by a reduction treatment, or a firing treatment and a reduction treatment, whereby counter ions (for example, Co (NO ₃ ) in the case of cobalt nitrate). in ₂ (NO ₃₎ ^-) is intended to volatilization particularly limited as long as it dissolves in the solvent is not, nitrates, carbonates, acetates, chlorides, although such acetylacetonate is available It is preferable to use a water-soluble compound that can be used as an aqueous solution during the carrying operation in order to reduce manufacturing costs and secure a safe manufacturing work environment. In the case where the metal compound is cobalt, cobalt nitrate or the like is preferable because it easily changes to cobalt oxide at the time of firing, and the subsequent reduction treatment of the cobalt oxide is easy.

  The catalyst for decomposing and lightening the hydrocarbons produced according to the present invention is not particularly limited as long as it is a solid acid catalyst having hydrocarbon decomposition activity, but zeolite, silica alumina (a composite oxidation of alumina and silica). ) Are common, and zeolite is preferred.

Zeolite is not particularly limited and can be appropriately selected from X-type zeolite, Y-type zeolite, β-type zeolite, mordenite, ZSM-5, etc., hydrocarbon decomposition activity and reaction temperature used, What is necessary is just to select according to the catalyst which manufactures a hydrocarbon from synthesis gas. The cation in the zeolite pores is preferably proton (H ⁺ ). For example, when cobalt is used as a metal compound active in the FT synthesis reaction, it is easy to obtain suitable performance by using proton type β-type zeolite or proton type ZSM-5 (H-ZSM-5). H-ZSM-5 is more preferable.

  The existence form of the catalyst for producing hydrocarbons from the synthesis gas and the catalyst for decomposing and lightening the produced hydrocarbons is not particularly limited, and the hydrocarbons are produced from the mixture obtained by physically mixing the respective particles or the synthesis gas. One-piece catalyst particles in which a catalyst that decomposes and lightens hydrocarbons on the outer surface of the catalyst can be used. The mixing ratio of the catalyst that produces hydrocarbons from synthesis gas and the catalyst that decomposes and lightens hydrocarbons is not particularly limited, but by weight ratio (catalyst producing hydrocarbons from synthesis gas) / (hydrocarbon decomposition) Thus, the range of 15/1 to 1/5 is preferable, more preferably 10/1 to 1/1, and still more preferably 5/1 to 2/1. If the amount of catalyst for producing hydrocarbons from synthesis gas exceeds this range, the effect of suppressing the heat generation amount of the entire system will be insufficient, or the generated WAX will not be light enough and the microchannel will be blocked. If the amount of catalyst that decomposes and lightens hydrocarbons beyond this range increases, the conversion activity from synthesis gas to hydrocarbons is not sufficient, and gaseous products such as methane increase. Therefore, it is not preferable.

In the case of using zeolite as a catalyst for decomposing and lightening hydrocarbons, from the viewpoint of reducing CH ₄ selectivity, an integrated type in which zeolite is formed on the outer surface of a catalyst for producing hydrocarbons from synthesis gas. It is preferred to use catalyst particles.

  As a method for producing integrated catalyst particles in which zeolite is formed on the outer surface of a catalyst for producing hydrocarbons from synthesis gas, a catalyst for producing hydrocarbons from synthesis gas is first produced by the above-described method, and hydrothermal A method of forming zeolite on the outer surface of the catalyst by a synthesis method can be employed. In this case, the mixing ratio of the catalyst for producing hydrocarbons from synthesis gas and the catalyst for decomposing and lightening hydrocarbons can be controlled by the conditions of hydrothermal synthesis such as time.

  Below, an example of the method of obtaining said catalyst is shown. First, an aqueous solution of a precursor of a metal compound such as cobalt is impregnated with a silica carrier and supported, and then dried as necessary (100 ° C. to 1 h, usually in the range of about 50 to 150 ° C., but not particularly limited) ), Calcining treatment (450 ° C to 10h, usually in the range of about 300 ° C to 600 ° C, but not particularly limited) to obtain a catalyst for producing hydrocarbons from synthesis gas (FT synthesis catalyst) be able to. 10 mass% tetrapropylammonium hydroxide, tetraethyl orthosilicate, aluminum nitrate, ion-exchanged water, and ethanol are charged in appropriate amounts, respectively, and stirred (room temperature -6h, not particularly limited) to prepare a precursor solution, FT synthesis Zeolite can be formed on the outer surface of the FT synthesis catalyst by hydrothermal synthesis in which the catalyst is added and heated while being rotated at 2 rpm (180 ° C.-48 h, not particularly limited).

  As the time of hydrothermal synthesis increases, the thickness of the zeolite formed on the outer surface of the catalyst for producing hydrocarbons from synthesis gas increases. The thickness of the zeolite is not particularly limited, but is usually 1 to 40 μm, preferably 2 to 30 μm, and more preferably 3 to 20 μm. If the temperature falls below this range, the temperature control becomes difficult because the effect of suppressing the heat generation of the entire system becomes insufficient, and the possibility that the generated WAX will not be light enough and the microchannel will be clogged increases. When this range is exceeded, the decomposition of hydrocarbons proceeds more than necessary, and a large amount of hydrocarbons, such as methane, which are gaseous at normal temperature and pressure are produced.

Moreover, in the catalyst which decomposes | disassembles and lightens hydrocarbons other than zeolites, such as a silica alumina, the method of coating sol, such as a silica alumina, on the catalyst which manufactures a hydrocarbon from the synthesis gas prepared previously can be employ | adopted.
If the catalyst that decomposes and lightens hydrocarbons is formed on the outer surface of the catalyst that produces hydrocarbons from synthesis gas, the catalyst that decomposes and lightens hydrocarbons produces hydrocarbons from synthesis gas. Although it is preferable from the viewpoint of performance to cover the entire surface of the catalyst to be performed, a structure in which only a part is covered may be used.

  The channel width of the microchannel reactor is not particularly limited, but the channel width is 4 mm or less from the viewpoint of efficiently removing the reaction heat generated on the catalyst in the channel by the refrigerant flow in the adjacent channel. In addition to a structure in which the substrates are stacked in layers with the corrugated sheet sandwiched therebetween, a structure in which microchannels are formed on the substrate in layers or a honeycomb structure can be used. The material of the reactor can be a metal or an inorganic compound, and is not particularly limited, but a metal is preferable. As the metal, a steel material such as stainless steel, aluminum or the like is suitable.

  The FT synthesis reaction is an exothermic reaction, and efficient heat removal is effective for maintaining a stable and high reaction performance. It is possible to obtain good performance by using a microchannel reactor in which a flow path for performing an FT synthesis reaction and a flow path for removing heat by circulating a refrigerant are alternately layered (see FIG. 7). When such a microchannel reactor is used, the direction of supplying the raw material gas to the flow path for performing the FT synthesis reaction and the direction of supplying the refrigerant to the flow path for performing heat removal can be orthogonal. The refrigerant is not particularly limited as long as it can remove heat, but it is preferable to use boiler feed water (BFW) because the controllability of the temperature in the flow path for performing the FT synthesis reaction is good.

  From the viewpoint of controlling the temperature in the flow path of the microchannel reactor, if the flow path width is reduced, heat removal can be efficiently performed, preferably 2 mm or less, more preferably 1.5 mm or less. From the viewpoint of controlling the temperature in the flow path, it is preferable that the flow path width is small, but if the flow path becomes too small and the substrate thickness forming the flow path becomes too large, the productivity per unit volume becomes small. When determining the channel width, it is necessary to consider productivity.

  The productivity per unit volume also contributes to the thickness of the substrate that forms the flow path and the corrugated plate in the flow path, so these thicknesses are within the range where FT synthesis reaction and heat removal can be performed safely. Is preferably thinner. For example, in a microchannel reactor using stainless steel, the thickness of the substrate or corrugated plate can be selected from about 30 to 200 μm.

  As shown in FIG. 6, the fixing of the catalyst for producing light hydrocarbons from the synthesis gas in the microchannel reactor can be performed by a method of filling a catalyst having a particle diameter smaller than the channel width, A method of applying a catalyst having a particle diameter sufficiently smaller than the width to the inner wall of the flow path (the surface of the substrate and the corrugated plate) can be employed. From the viewpoint of the production of light hydrocarbons per unit volume of the reactor, it is preferable to use catalyst packing that can contain a relatively large amount of catalyst.

  When using a microchannel reactor packed with a catalyst, the average particle size of the catalyst needs to be 400 μm or less, and there is no particular lower limit, but considering the pressure loss in the catalyst layer due to the supply of raw material gas Usually, 5 μm or more is preferable. From the viewpoint of operation stability and reactivity considering both pressure loss and catalyst packing rate, an average particle size of 20 μm to 300 μm is preferable, more preferably 25 μm to 250 μm, and still more preferably 30 μm to 200 μm.

  The average particle diameter of the catalyst referred to here is one of those in the case of an integrated catalyst in which a catalyst for decomposing and lightening hydrocarbons formed on the outer surface of the catalyst for producing hydrocarbons from synthesis gas is formed. This is the average particle size of the body-shaped catalyst. In the case of a catalyst that physically mixes these catalysts instead of an integral catalyst, each catalyst particle exists as a separate particle and is composed of a mixture of two or more, the average of the catalysts that produce hydrocarbons from synthesis gas Refers to particle size. The reason for using the average particle size of a catalyst that produces hydrocarbons from synthesis gas in the case of a catalyst that is physically mixed is that the catalyst particle size that generally decomposes and lightens hydrocarbons produces hydrocarbons from synthesis gas. The size of the catalyst is sufficiently small (generally several μm to several tens of μm), and from the viewpoint of the filling rate and mixing degree of the microchannel reactor, the influence of the relatively large catalyst particle size is large. is there. When the physical mixed catalyst has a structure in which a mixture of both catalysts is contained in one particle, the particle diameter is the same as that of the integral catalyst. In addition, the laser diffraction method is applied to the measurement of the average particle diameter in the present invention. When measurement by the laser diffraction method is difficult due to poor dispersibility or the like, a method such as an image imaging method should be applied. Can do.

  In addition, when using a microchannel reactor in which the catalyst is applied to the inner wall of the flow path, the average particle diameter of the catalyst is preferably smaller than that in the case of packing, and is not particularly limited, but 150 μm The following average particle diameter is preferable, and more preferably, the average particle diameter is 5 to 100 μm or less. When the average particle size exceeds 150 μm, it becomes difficult to apply uniformly, and thus the problem that the catalyst is localized and fixed in the flow path or peels easily occurs. It is preferable to use in the range of diameter.

  As a method of applying the catalyst to the inner wall of the flow path, a normal method such as wash coating can be employed. For example, when the material is a metal, it is possible to employ a multi-stage washcoat in which an inorganic compound such as alumina is applied in advance by a method such as washcoat, and then a coating liquid containing a catalyst is applied. The coating liquid containing the catalyst can contain an inorganic compound such as alumina, and the operation can be repeated until a desired coating amount is obtained.

  The coating thickness in the microchannel reactor is preferably 10 to 400 μm, more preferably 50 to 300 μm, although it depends on the channel width. Below this range, the amount of catalyst fixed to the microchannel is reduced, and the productivity per unit volume is reduced, which is not preferable. Over this range, the number of repetitions of the coating operation increases, requiring time, and synthesis gas. The diffusion of the catalyst is insufficient and the catalyst fixed on the channel wall side is not preferable because it may not sufficiently contribute to the reaction.

  When performing a reaction for producing light hydrocarbons in a microchannel reactor, a metal compound having activity in the FT synthesis reaction on a catalyst for producing hydrocarbons needs to form a reduced metal. Before supplying the synthesis gas to produce light hydrocarbons, reducing gas such as hydrogen gas is circulated and reduced (for example, 400 ° C-10h, usually in the range of about 300-500 ° C. Not limited). A light hydrocarbon can be produced by switching to synthesis gas after the metal is formed on the catalyst by such treatment.

  In addition to the above-described method of filling or coating and fixing the catalyst that is not subjected to the reduction treatment, it is possible to perform the reduction treatment before charging the catalyst into the microchannel reactor and then charge the catalyst. The catalyst after the reduction treatment must be handled so as not to be oxidized and deactivated by exposure to the atmosphere. However, if the stabilization treatment is performed to block the surface of cobalt metal etc. on the support from the atmosphere, the catalyst should be handled in the atmosphere. Is possible and preferable. This stabilization treatment involves so-called passivation (passivation treatment) in which only the surface layer of cobalt metal or the like on the support is oxidized by bringing nitrogen, carbon dioxide, or inert gas containing low concentrations of oxygen into contact with the catalyst. It is good to do. In many cases, such as a wash coat for application fixation, an aqueous solution is included in the coating solution, so it is not efficient to apply the reduced catalyst, but depending on the composition of the applied solution, the reduced catalyst is applied. It can also be fixed.

The reaction conditions of the reaction for producing light hydrocarbons in the microchannel reactor produced using the above-described configuration or production method are not particularly limited, but the reaction temperature is 220 to 300 ° C. and the reaction pressure is 0.8 to 3.5 MPa. The reaction temperature is 240 to 280 ° C., and the reaction pressure is 0.9 to 2.5 MPa. The H ₂ / CO ratio of the synthesis gas is not particularly limited, but is preferably 0.5 to 3 when the metal compound active in the FT synthesis reaction in the catalyst for producing hydrocarbons from the synthesis gas is cobalt or ruthenium, Preferably it is 1-2.5. When the main component of the metal compound active in the FT synthesis reaction in the catalyst for producing hydrocarbons from synthesis gas is iron, 0.5 to 2 is preferable, and 0.7 to 1.5 is more preferable. In the reaction carried out under such conditions, light hydrocarbons can be selectively produced, so that the viscosity of the product oil is low and pressure loss in the flow path can be suppressed. Therefore, clogging due to WAX generation in the microchannel reactor does not occur. In addition, when a catalyst for producing hydrocarbons from synthesis gas is used alone, most of the product oil is straight-chain paraffin. However, isoparaffins and olefins can be used together with a catalyst that decomposes and lightens hydrocarbons. Can also be manufactured at the same time.

  When the activity is reduced due to a remarkably high conversion rate or a long reaction time, the catalyst can be regenerated by supplying a gas containing hydrogen instead of the synthesis gas. The hydrogen content of the regeneration gas is preferably 5% or more, and may be 100%. In addition, you may contain inert gas, such as nitrogen and argon. The regeneration conditions are not particularly limited as long as catalyst regeneration proceeds. The catalyst regeneration mechanism by bringing the regeneration gas containing hydrogen into contact with the catalyst is assumed to be due to re-reduction of cobalt or the like oxidized by by-product water and removal of precipitated carbon by hydrogen. As the regeneration conditions, for example, the regeneration temperature is preferably 100 to 400 ° C., the regeneration pressure is normal pressure to the reaction pressure, and the regeneration time is 1 hour or more. If the regeneration pressure is less than or equal to the reaction pressure, it is possible to use a compressor for raising the reaction pressure to the reaction pressure, and it is not necessary to install a new compressor for regeneration, which is advantageous in terms of equipment costs. .

The synthesis gas used in the present invention is preferably a gas in which the total amount of hydrogen and carbon monoxide is 50% by volume or more from the viewpoint of productivity, and in particular, the molar ratio of hydrogen to carbon monoxide (hydrogen / carbon monoxide). Carbon monoxide) is desirably in the range of 0.5 to 4.0. This is because when the molar ratio of hydrogen to carbon monoxide is less than 0.5, the amount of hydrogen in the raw material gas is too small, so the carbon monoxide hydrogenation reaction (FT synthesis reaction) is difficult to proceed, and liquid carbonization This is because the productivity of hydrogen does not increase. On the other hand, when the molar ratio of hydrogen to carbon monoxide exceeds 4.0, the amount of carbon monoxide in the raw material gas is too small, so that it is liquid regardless of the catalyst activity. This is because the productivity of hydrocarbons does not increase.
In the present invention, the reason why the catalyst for producing hydrocarbons from synthesis gas and the catalyst for decomposing and lightening hydrocarbons coexist and the methane selectivity can be suppressed by using a catalyst having a small particle diameter is as follows. Considering that methane selectivity is lower in reactions with relatively low reaction temperatures and relatively high water pressures, the reaction temperature locally depends on the endothermic reaction that occurs on the catalyst that decomposes and lightens hydrocarbons. If a catalyst that decomposes and lightens hydrocarbons is formed on the outer surface of the catalyst that produces hydrocarbons from synthesis gas, the catalyst that decomposes and lightens hydrocarbons Due to structural and property characteristics, water produced as a by-product of the reaction is less likely to be discharged from the inside of the catalyst, and the water pressure in the catalyst may increase, resulting in a reduction in methane selectivity. It is considered to be.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further in detail, this invention is not limited to these Examples and a comparative example.

[Example 1]
Using a silica carrier with an average particle size of 110 μm, after supporting Co by an incipient wetness method using a Co (NO ₃ ) ₂ · 6H ₂ O aqueous solution, drying treatment at 120 ° C.-12 h, baking at 400 ° C.-2 h A catalyst (Co / SiO ₂ ) for producing hydrocarbons from synthesis gas was prepared. The amount of Co supported was 10% by mass.
The silica carrier used here has a pore diameter of 13 nm, a pore volume of 1 cc / g, and a specific surface area of 300 m ² / g.

10% by mass of tetrapropylammonium hydroxide, aluminum nitrate, ion-exchanged water, ethanol, and tetraethyl orthosilicate were sequentially charged into a Teflon (registered trademark) container and stirred at room temperature for 6 hours to prepare a uniform precursor solution. The molar ratio of the precursor solution was (10 wt% tetrapropylammonium hydroxide: aluminum nitrate: ion exchange water: ethanol: tetraethyl orthosilicate) = (20: 1: 4,800: 320: 80). Hydrothermal synthesis is performed by adding 0.5 g of a catalyst (Co / SiO ₂ ) for producing hydrocarbons from the above synthesis gas to 23.4 g of the prepared precursor solution, rotating at 2 rpm while heating at 180 ° C., and maintaining for 48 hours. It was. Take out the solid catalyst, wash with ion-exchanged water until the pH becomes neutral, perform 120 ℃ -12h drying treatment, 500 ℃ -8h calcination treatment to decompose hydrocarbons and lighten the catalyst (H- An H-ZSM-5 / Co / SiO ₂ catalyst (average particle size of 120 μm) formed on the outer surface of a catalyst (Co / SiO ₂ ) from which ZSM-5) produces hydrocarbons from synthesis gas was obtained.
The particle diameter of the catalyst is a volume-based average diameter measured by a laser diffraction method (manufactured by Malvern, laser diffraction particle size distribution measuring device Mastersizer 2000).

1 g of the H-ZSM-5 / Co / SiO ₂ catalyst obtained above is charged into an 8 mmφ tube reactor, subjected to reduction treatment at 400 ° C for 10 h at normal pressure, and is cooled to 80 ° C by replacing with nitrogen. After that, the synthesis gas was switched to H ₂ / CO = 2. The reaction temperature was set at 260 ° C, reaction pressure at 1.0 MPa, W (catalyst mass) / F (synthesis gas flow rate); (g The CO conversion, CH ₄ selectivity, C5 + selectivity, olefin selectivity, and isoparaffin selectivity were calculated by chromatography.
The CO conversion, CH ₄ selectivity, C5 + selectivity, olefin selectivity, and isoparaffin selectivity described in the following examples were calculated by the following formulas. Here, C5 + represents a hydrocarbon having 5 or more carbon atoms.

When the reaction was carried out using the catalyst prepared above, the CO conversion was 78.9%, the CH ₄ selectivity was 15.6%, the C5 + selectivity was 74.2%, the olefin selectivity was 20.5%, and the isoparaffin selectivity was 24.8%. Moreover, the product of carbon number distribution shown in FIG. 1 was obtained. Compared with the H-ZSM-5 / Co / SiO ₂ catalyst produced using a silica carrier having an average particle size of 1.3 mm shown in Comparative Example 1 described later, the CH ₄ selectivity was low and good reaction performance was exhibited. In addition, it was confirmed that the carbon number distribution of the product was lightened as compared to the Co / SiO ₂ catalyst which does not have a catalyst for decomposing and lightening hydrocarbons shown in Comparative Example 2 described later.

(Example 2)
The reaction was carried out in the same manner as in Example 1 except that the tubular reactor had a double tube structure and normal temperature water was passed through the center. The temperature rise of the water after distribution was 8 ° C.

Example 3
The reaction was conducted in the same manner as in Example 1 except that the hydrothermal synthesis time in the catalyst preparation was 96 hours.The CO conversion was 75.2%, the CH ₄ selectivity was 16.4%, the C5 + selectivity was 72.2%, and the olefin was selected. The rate was 35.2% and the isoparaffin selectivity was 20.6%.

(Example 4)
The reaction was performed in the same manner as in Example 1 except that W / F was set to 20 g · h / mol.The CO conversion was 95.8%, the CH ₄ selectivity was 4.9%, the C5 + selectivity was 87.8%, and the olefin was selected. The rate was 35.7% and the isoparaffin selectivity was 32.5%.

Example 5
The reaction was conducted in the same manner as in Example 2 except that W / F was set to 20 g · h / mol.The CO conversion was 96.3%, the CH ₄ selectivity was 3.5%, the C5 + selectivity was 89.0%, and the olefin was selected. The rate was 34.2%, and the isoparaffin selectivity was 38.9%.

Example 6
A reaction was conducted in the same manner as in Example 1 except that an H-ZSM-5 / Co / SiO ₂ catalyst (average particle diameter 210 μm) produced using a silica carrier having an average particle diameter 200 μm was used. Conversion was 80.1%, CH ₄ selectivity was 18.9%, C5 + selectivity was 69.1%, olefin selectivity was 22.5%, and isoparaffin selectivity was 23.9%.

Example 7
A reaction was conducted in the same manner as in Example 1 except that an H-ZSM-5 / Co / SiO ₂ catalyst (average particle diameter 360 μm) produced using a silica support having an average particle diameter of 350 μm was used. The conversion was 80.9%, CH ₄ selectivity 20.4%, C5 + selectivity 65.7%, olefin selectivity 21.5%, isoparaffin selectivity 24.4%.

(Example 8)
When the reaction was carried out in the same manner as in Example 1 except that the Co / SiO ₂ catalyst (average particle size 110 μm) and H-ZSM-5 were physically mixed (each catalyst particle exists as a separate particle), The CO conversion was 83.4%, the CH ₄ selectivity was 18.5%, the C5 + selectivity was 71.5%, the olefin selectivity was 27.5%, and the isoparaffin selectivity was 23.7%. Moreover, the product of carbon number distribution shown in FIG. 2 was obtained.

Example 9
The reaction was conducted in the same manner as in Example 7 except that a Co / SiO ₂ catalyst (average particle diameter 200 μm) produced using a silica carrier having an average particle diameter of 200 μm was used. As a result, the CO conversion was 82.1%, CH _{4 The} selectivity was 18.1%, the C5 + selectivity was 72.9%, the olefin selectivity was 26.1%, and the isoparaffin selectivity was 23.2%.

Example 10
The reaction was conducted in the same manner as in Example 7 except that a Co / SiO ₂ catalyst (average particle diameter 350 μm) produced using a silica carrier having an average particle diameter of 350 μm was used. As a result, the CO conversion was 81.8%, CH _{4 The} selectivity was 18.7%, the C5 + selectivity was 71.9%, the olefin selectivity was 25.5%, and the isoparaffin selectivity was 22.9%.

Example 11
Other H-beta zeolite to use Co / are formed on the SiO ₂ outer surface H-beta / Co / SiO ₂ catalyst (average particle size 120 [mu] m), the same procedure as in Example 1 was subjected to a reaction The CO conversion was 73.2%, the CH ₄ selectivity was 17.6%, the C5 + selectivity was 71.2%, the olefin selectivity was 18.1%, and the isoparaffin selectivity was 21.5%.

Example 12
Same as Example 1 except that H-ZSM-5 / molten iron catalyst (average particle size 120μm) with H-ZSM-5 formed on the outer surface of molten iron was used and the reaction temperature was 300 ° C. As a result of the reaction, the CO conversion was 71.2%, the CH ₄ selectivity was 11.6%, the C5 + selectivity was 68.5%, the olefin selectivity was 14.9%, and the isoparaffin selectivity was 29.7%.

Example 13
Except for charging the catalyst into a 1.3 mm cross-sectional width microchannel reactor with corrugated plates arranged in the flow path in a laminated structure of SUS foil and controlling the temperature while cooling with BFW, the same as in Example 1 As a result of the reaction, the CO conversion was 75.7%, the CH ₄ selectivity was 13.8%, the C5 + selectivity was 78.5%, the olefin selectivity was 21.4%, and the isoparaffin selectivity was 25.8%.

Example 13
The reaction pressure was 2.0 MPa, W (catalyst mass) / F (synthesis gas flow rate); (g · h / mol) = 3, except that the reaction was carried out in the same manner as in Example 1, the CO conversion rate was The selectivity was 40.6%, CH ₄ selectivity 9.2%, C5 + selectivity 76.1%, olefin selectivity 17.8%, and isoparaffin selectivity 21.5%.
Moreover, in any of Examples 1-13, the tube | bowl obstruction | occlusion by WAX production did not arise.

(Comparative Example 1)
A reaction was conducted in the same manner as in Example 1 except that an H-ZSM-5 / Co / SiO ₂ catalyst (average particle diameter 1.31 mm) produced using a silica support having an average particle diameter of 1.3 mm was used. The CO conversion was 82.0%, the CH ₄ selectivity was 32.5%, the C5 + selectivity was 41.5%, the olefin selectivity was 19.5%, and the isoparaffin selectivity was 21.8%.

As described above, a catalyst corresponding to a conventional catalyst (a catalyst having a large particle diameter in which an FT synthesis catalyst and a catalyst for lightening hydrocarbons coexist) developed assuming use in a fixed bed has a methane selectivity. It was confirmed that there was a problem in production efficiency because of its high value.
(Comparative Example 2)
The reaction was carried out in the same manner as in Comparative Example 1 except that the tubular reactor had a double tube structure and normal temperature water was circulated in the center. The increase in the temperature of water after circulation was 16 ° C., which was larger than that in Example 2, and it was confirmed that the heat generation amount of the system was large because the abundance ratio of H-ZSM-5 causing an endothermic reaction was low.

(Comparative Example 3)
The reaction was performed in the same manner as in Comparative Example 1 except that the Co / SiO ₂ catalyst (average particle size 1.31 mm) and H-ZSM-5 were physically mixed (each catalyst particle exists as a separate particle). The CO conversion was 92.1%, the CH ₄ selectivity was 19.5%, the C5 + selectivity was 69.8%, the olefin selectivity was 25.8%, and the isoparaffin selectivity was 15.8%.

(Comparative Example 4)
The reaction was carried out in the same manner as in Example 1 except that a Co / SiO ₂ catalyst (average particle size 110 μm) was used alone without using a catalyst that decomposes hydrocarbons to lighten them. The selectivity was 98.1%, CH ₄ selectivity was 15.0%, C5 + selectivity was 75.2%, olefin selectivity was 5.5%, and isoparaffin selectivity was 8.5%. Moreover, the product of carbon number distribution shown in FIG. 3 was obtained.

(Comparative Example 5)
The reaction was carried out in the same manner as in Comparative Example 4 except that the tubular reactor had a double tube structure and normal temperature water was circulated in the center. The temperature rise of the water after distribution was 18 ° C., which was larger than that of Example 2, and it was confirmed that the heat generation amount of the system was large because there was no H-ZSM-5 that caused an endothermic reaction.

(Comparative Example 6)
The reaction was carried out in the same manner as in Comparative Example 2 except that a Co / SiO ₂ catalyst (average particle diameter 1.3 mm) produced using a silica support having an average particle diameter of 1.3 mm was used. The CO conversion was 97.5%. The CH ₄ selectivity was 15.8%, the C5 + selectivity was 73.8%, the olefin selectivity was 4.5%, and the isoparaffin selectivity was 3.1%.

Claims (11)

A catalyst for producing light hydrocarbons from synthesis gas,
A catalyst containing a metal compound active in a Fischer-Tropsch synthesis reaction and producing hydrocarbons from synthesis gas;
A catalyst that decomposes the produced hydrocarbons to lighten them,
A catalyst for producing light hydrocarbons from synthesis gas, wherein the average particle size is 400 μm or less.   The catalyst for producing light hydrocarbons from synthesis gas according to claim 1, wherein the average particle size is 200 μm or less.   The catalyst for producing light hydrocarbons from synthesis gas according to claim 1 or 2, wherein the metal of the metal-based compound contains cobalt.   The catalyst for producing light hydrocarbons from synthesis gas according to any one of claims 1 to 3, wherein the catalyst for decomposing and lightening the generated hydrocarbons is zeolite.   The catalyst which decomposes | disassembles the produced | generated hydrocarbon and lightens is formed in the outer surface of the catalyst which manufactures the hydrocarbon from the said synthesis gas, The any one of Claims 1-4 characterized by the above-mentioned. That produces light hydrocarbons from the synthesis gas.   The catalyst for producing light hydrocarbons from synthesis gas according to any one of claims 1 to 5, wherein the carrier of the catalyst for producing hydrocarbons from the synthesis gas is silica.   A method for producing the catalyst according to claim 5 or 6, wherein the catalyst is produced on a silica support from a synthesis gas using an impregnation method, an incipient wetness method, a precipitation method, or an ion exchange method. And then forming a catalyst that decomposes and lightens the generated hydrocarbon on the outer surface of the produced catalyst using a hydrothermal synthesis method. The manufacturing method of the catalyst which manufactures.   A method for producing light hydrocarbons, comprising producing light hydrocarbons from synthesis gas in a microchannel reactor using the catalyst according to any one of claims 1 to 6.   9. The light hydrocarbon production method according to claim 8, wherein a flow path width of the microchannel reactor is 4 mm or less.   The method for producing light hydrocarbons according to claim 8 or 9, wherein the microchannel reactor is made of a metal material.   The microchannel reactor has a multi-stage layered structure in which layers for supplying synthesis gas to produce light hydrocarbons and layers for supplying refrigerant and removing heat generated in light hydrocarbon production are alternately arranged. The method for producing light hydrocarbons according to any one of claims 8 to 10, wherein the flow paths of these layers are arranged in a direction orthogonal to each other.

Images