Catalyst for fischer-tropsch synthesis reaction and method for producing said catalyst, and hydrocarbon production apparatus and hydrocarbon production method

Abstract

The present invention addresses the problem of providing: a technology related to a catalyst for a Fischer-Tropsch synthesis reaction (FT synthesis reaction) capable of, in the FT synthesis reaction, more easily obtaining a hydrocarbon having a specific number of carbon atoms, and a method for producing said catalyst; and a technology related to a hydrocarbon production apparatus and a hydrocarbon production method.　In order to solve said problem, provided are: a catalyst for FT synthesis, in which an active metal is supported on the surface of a carrier, the carrier contains silicon or aluminum, the active metal contains at least one selected from cobalt, ruthenium, and iron, and the metal density per specific surface area of the carrier is within a specific range; a method for producing said catalyst; and a hydrocarbon production apparatus and a hydrocarbon production method using the catalyst.　According to the present invention, it is possible to: improve the CO conversion rate in an FT synthesis reaction and improve the selectivity of the number of carbon atoms in an obtained hydrocarbon; and more easily generate a hydrocarbon having a specific number of carbon atoms.

Description

Fischer-Tropsch synthesis catalyst, method for producing the catalyst, hydrocarbon production apparatus, and hydrocarbon production method

[0001] The present invention relates to a catalyst for the Fischer-Tropsch synthesis reaction (hereinafter also referred to as the "FT synthesis reaction") and a method for producing the catalyst. The present invention also relates to a hydrocarbon production apparatus and a hydrocarbon production method using the catalyst for the FT synthesis reaction. More specifically, the present invention relates to a catalyst for the FT synthesis reaction that can produce saturated hydrocarbons having a specific carbon number, a method for producing the catalyst, and a hydrocarbon production apparatus and a hydrocarbon production method.

[0002] The FT synthesis reaction is a reaction in which a mixed gas of carbon monoxide and hydrogen is reacted in the presence of a catalyst to produce a hydrocarbon mixture.

[0003] In the FT synthesis reaction, studies are being conducted to improve the selectivity of the types of hydrocarbon mixture produced by the catalyst used. For example, Patent Document 1 describes an example of a method for producing hydrocarbons by the FT synthesis reaction, in which a manganese oxide support containing a ruthenium catalyst to which an alkali metal (potassium in the example) is added is used, and the method is applied to a liquid-phase slurry method, thereby improving the olefin selectivity and conversion rate of the olefin / paraffin ratio in the produced hydrocarbons.

[0004] Japanese Patent Application Laid-Open No. 2002-161279

[0005] Of the hydrocarbons obtained by the FT synthesis reaction, saturated hydrocarbons with approximately 8 to 16 carbon atoms have been used as kerosene and diesel, but in recent years, attention has been focused on their use as jet fuel called SAF (Sustainable Aviation Fuel) from the perspective of reducing carbon dioxide emissions. Thus, SAF is becoming an important middle distillate on a par with kerosene and diesel fractions.

[0006] Patent Document 1 describes that an FT synthesis reaction using a catalyst made of a manganese oxide support carrying ruthenium and an alkali metal increases the production of kerosene and diesel fractions by hydrocracking the produced wax and dimerizing and trimerizing the produced olefins. To obtain jet fuel, kerosene, or diesel using the conventional technology described in Patent Document 1, the following steps are required: (1) Separation of liquid hydrocarbons from wax, (2) Distillation of liquid hydrocarbons, and (3) Upgrading of wax (hydrocracking and hydrotreating). Therefore, the conventional technology required at least additional equipment such as a distillation unit, hydrocracking unit, and hydrogenation unit in addition to a reactor for performing the FT synthesis reaction.

[0007] Under these circumstances, in order to advance technological development related to SAF, which is expected to contribute to the realization of a carbon-neutral society, it is necessary to carry out fuel synthesis alongside carbon dioxide capture equipment and hydrogen electrolysis production equipment, and there is an urgent need to develop new technologies that can eliminate or simplify the ancillary equipment. In other words, there is a need for technologies that can reduce the facilities and equipment that make up the plant in order to produce SAF on-site, and make it easier to obtain SAF.

[0008] An object of the present invention is to provide a technology relating to a Fischer-Tropsch synthesis catalyst that can more easily produce hydrocarbons having a specific carbon number in a Fischer-Tropsch synthesis reaction, and a method for producing the catalyst. Additionally, an object of the present invention is to provide a technology relating to a hydrocarbon production apparatus and a hydrocarbon production method that can use the Fischer-Tropsch synthesis catalyst to reduce the facilities and equipment that make up a plant and more easily produce hydrocarbons having a specific carbon number on-site.

[0009] As a result of intensive research into the above-mentioned problems, the present inventors have found that, with respect to a catalyst used in a Fischer-Tropsch synthesis reaction, by supporting an active metal on the surface of a support so that the metal density per specific surface area of ​​the support falls within a specific range, it is possible to increase the selectivity for producing saturated hydrocarbons having a specific carbon number (particularly a carbon number of 16 or less) in the FT synthesis reaction, and to easily obtain useful saturated hydrocarbons that can be used in SAF and the like, and have completed the present invention.

[0010] The Fischer-Tropsch synthesis catalyst of the present invention for solving the above problems is a catalyst used in the Fischer-Tropsch synthesis reaction, in which an active metal is supported on the surface of a carrier, the carrier containing silicon or aluminum, the active metal containing at least one selected from cobalt, ruthenium, and iron, and the metal density per specific surface area of ​​the carrier is: cobalt: 3 to 9.5 μmol / m ２ , ruthenium: 0.3 to 2.5 μmol / m ２ , iron: 5 to 15 μmol / m ２ The present inventors have conducted extensive research and have found that, with regard to a catalyst used in the FT synthesis reaction, the density of the active metal supported on the support surface is involved in improving the CO conversion rate, and that the density of the active metal supported on the support surface affects the value of the chain growth probability (α) and is involved in improving the selectivity for the production of hydrocarbons (saturated hydrocarbons) obtained by the FT synthesis reaction. The Fischer-Tropsch synthesis catalyst of the present invention is based on the above-mentioned finding obtained by the present inventors. By using a catalyst used in the FT synthesis reaction in which an active metal is supported on the support surface and supporting the active metal so that the metal density per specific surface area of ​​the support is within a specific range, it is possible to improve the CO conversion rate in the FT synthesis reaction and improve the selectivity for the carbon number of the resulting hydrocarbons (saturated hydrocarbons), and it becomes possible to more easily produce hydrocarbons having a specific carbon number, in particular saturated hydrocarbons useful as SAF.

[0011] Furthermore, one embodiment of the Fischer-Tropsch synthesis catalyst of the present invention is characterized in that it further contains at least one selected from potassium, rubidium, and cesium. According to the present invention, by containing at least one auxiliary catalyst selected from potassium, rubidium, and cesium in addition to the active metal that serves as the main catalyst, carbon deposition in the FT synthesis reaction is suppressed, thereby suppressing catalyst deterioration, and chain growth is promoted, preventing the gas fraction (having 4 or less carbon atoms) from becoming excessive in the obtained hydrocarbons, thereby further improving selectivity for the jet fuel (SAF) fraction containing hydrocarbons having about 8 to 16 carbon atoms.

[0012] Furthermore, one embodiment of the Fischer-Tropsch synthesis catalyst of the present invention is characterized in that the active metal is cobalt and the catalyst contains at least one selected from yttrium, lanthanum, cerium, and holmium. According to the present invention, from the viewpoint of achieving both catalytic activity and cost, the active metal is selected from cobalt, and the catalyst contains at least one selected from yttrium, lanthanum, cerium, and holmium, which not only improves the dispersion of the active metal (cobalt) on the catalyst surface and increases the number of reaction active sites, but also reduces the CO ２ Adsorption promotion and CO ２ This makes it possible to improve the conversion rate, and thus, even when carbon dioxide is mixed into the feed gas in the FT synthesis reaction, it becomes possible to efficiently and simply produce hydrocarbons having a specific carbon number, particularly saturated hydrocarbons useful as SAF.

[0013] One embodiment of the Fischer-Tropsch synthesis catalyst of the present invention is characterized in that it is formed into pellets. According to the present invention, by forming the catalyst into pellets, the surface area of ​​the catalyst before use in the FT synthesis reaction can be reduced, and reoxidation of the catalyst (mainly the active metal) due to contact with air during storage, etc. can be suppressed. This makes it possible to suppress a decrease in catalytic activity as a Fischer-Tropsch synthesis catalyst.

[0014] Further, in order to solve the above-mentioned problems, the present invention provides a method for producing a catalyst for a Fischer-Tropsch synthesis reaction, which is a method for producing a catalyst used in a Fischer-Tropsch synthesis reaction, and includes an active metal supporting step of supporting an active metal on a surface of a carrier, the carrier containing silicon or aluminum, and the active metal containing at least one selected from cobalt, ruthenium, and iron, and the active metal supporting step includes the steps of: cobalt: 3 to 9.5 μmol / m as a metal density of the active metal per specific surface area of ​​the carrier; ２ , ruthenium: 0.3 to 2.5 μmol / m ２ , iron: 5 to 15 μmol / m ２ The method for producing a catalyst for a Fischer-Tropsch synthesis reaction of the present invention is characterized in that the active metal is supported on the support surface so that at least one of the following is selected. As described above, the method for producing a catalyst for a Fischer-Tropsch synthesis reaction of the present invention is based on the findings of the present inventors, and when supporting an active metal on the support surface to obtain a catalyst for use in the FT synthesis reaction, the active metal is supported so that the metal density per specific surface area of ​​the support is within a specific range. This makes it possible to obtain a catalyst that improves the CO conversion in the FT synthesis reaction and improves the selectivity for the carbon number of the resulting hydrocarbons (saturated hydrocarbons). This makes it possible to more easily produce hydrocarbons having a specific carbon number, in particular saturated hydrocarbons that are useful as SAF.

[0015] Furthermore, one embodiment of the method for producing a Fischer-Tropsch synthesis catalyst of the present invention is characterized by comprising, after the active metal loading step, a forming step of forming the catalyst into pellets and a stabilization step of performing a stabilization treatment. According to the present invention, by forming the catalyst, the surface area of ​​the catalyst before use in the FT synthesis reaction can be reduced, and reoxidation of the catalyst (mainly the active metal) due to contact with the outside air during storage can be suppressed. This makes it possible to suppress a decrease in catalytic activity as a Fischer-Tropsch synthesis catalyst. Furthermore, by performing the stabilization treatment, it is possible to moderate the reaction conditions (catalyst activation conditions) when the catalyst is used in the FT synthesis reaction, making it possible to more easily produce hydrocarbons having a specific carbon number, particularly saturated hydrocarbons useful as SAF.

[0016] Furthermore, the hydrocarbon production apparatus of the present invention, which solves the above-mentioned problems, is a hydrocarbon production apparatus that supplies a feedstock gas into a reaction vessel containing a reaction catalyst and produces hydrocarbons by a Fischer-Tropsch synthesis reaction, and is characterized in that the above-mentioned Fischer-Tropsch synthesis catalyst is used as the reaction catalyst. According to the hydrocarbon production apparatus of the present invention, hydrocarbons can be obtained by proceeding with the FT synthesis reaction using a catalyst that can improve the CO conversion rate in the FT synthesis reaction and improve the carbon number selectivity of the resulting hydrocarbons (saturated hydrocarbons). This makes it possible to reduce the facilities and equipment that make up the plant in hydrocarbon production by the FT synthesis reaction and more easily obtain hydrocarbons having a specific carbon number (particularly saturated hydrocarbons that are useful as SAF).

[0017] In one embodiment of the hydrocarbon production apparatus of the present invention, the feed gas contains carbon dioxide. According to the present invention, not only carbon monoxide but also carbon dioxide can be effectively used as the feed gas in the FT synthesis reaction. This enables fuel synthesis using carbon dioxide as a carbon source, contributes to carbon recycling, and can be suitably used as one of the technologies toward the creation of a resource-circulating society.

[0018] The hydrocarbon production method of the present invention, which solves the above-mentioned problems, is a hydrocarbon production method in which a feedstock gas is supplied into a reactor containing a reaction catalyst and hydrocarbons are produced by a Fischer-Tropsch synthesis reaction, and is characterized in that the above-mentioned Fischer-Tropsch synthesis catalyst is used as the reaction catalyst. According to the hydrocarbon production method of the present invention, hydrocarbons can be obtained by proceeding with the FT synthesis reaction using a catalyst that can improve the CO conversion in the FT synthesis reaction and improve the carbon number selectivity of the resulting hydrocarbons (saturated hydrocarbons). This makes it possible to reduce the facilities and equipment that make up a plant for hydrocarbon production by the FT synthesis reaction and more easily obtain hydrocarbons having a specific carbon number (particularly saturated hydrocarbons useful as SAF).

[0019] In one embodiment of the hydrocarbon production method of the present invention, the feed gas contains carbon dioxide. According to the present invention, not only carbon monoxide but also carbon dioxide can be effectively used as the feed gas in the FT synthesis reaction. This enables fuel synthesis using carbon dioxide as a carbon source, contributes to carbon recycling, and can be suitably used as one of the technologies toward the creation of a resource-circulating society.

[0020] The present invention can provide a technology relating to a Fischer-Tropsch synthesis catalyst that can more easily produce hydrocarbons having a specific carbon number in a Fischer-Tropsch synthesis reaction, and a method for producing the catalyst. In addition, the present invention can provide a technology relating to a hydrocarbon production apparatus and a hydrocarbon production method that can use the Fischer-Tropsch synthesis catalyst to reduce the facilities and equipment that make up a plant and more easily produce hydrocarbons having a specific carbon number on-site.

[0021] 1 is a schematic diagram illustrating a catalyst surface reaction in an FT synthesis reaction; 2 is a schematic diagram illustrating chain growth probability and the distribution of hydrocarbon (crude product) composition obtained by an FT synthesis reaction; 3 is a schematic explanatory diagram of a hydrocarbon production apparatus in an embodiment of the present invention; 4 is a graph showing the relationship between the density of the active metal on the support in a Fischer-Tropsch synthesis reaction catalyst that is an example of the present invention and the product distribution in the FT synthesis reaction;

[0022] Hereinafter, embodiments of the Fischer-Tropsch synthesis reaction catalyst and method for producing the catalyst, as well as the hydrocarbon production method and hydrocarbon production apparatus according to the present invention will be described in detail with reference to the drawings. Note that the Fischer-Tropsch synthesis reaction catalyst and method for producing the catalyst, as well as the hydrocarbon production apparatus and hydrocarbon production method described as embodiments are merely examples used to explain the Fischer-Tropsch synthesis reaction catalyst and method for producing the catalyst, as well as the hydrocarbon production apparatus and hydrocarbon production method according to the present invention, and are not limited thereto. Furthermore, the description of the hydrocarbon production method of this embodiment will be replaced with the description of the configuration and operation of the hydrocarbon production apparatus below.

[0023] First, an outline of the FT synthesis reaction will be explained with reference to FIG. 1. The FT synthesis reaction is a process in which synthesis gas (carbon monoxide (CO) and hydrogen (H ２ ) is contacted with a catalyst to form a methylene group (—CH ２ -) and methane (C １ ) ~ Wax (C ３０＋ ) to produce hydrocarbons with a wide range of carbon numbers.

[0024] It is also known that, depending on the conditions of the FT synthesis reaction (such as the type of catalyst), in addition to the FT synthesis reaction using carbon monoxide as a starting material as shown in Equation 1 above, an FT synthesis reaction using carbon dioxide as a starting material (Equation 2) also proceeds in parallel.

[0025] The reaction formula shown in formula 2 is a general chemical reaction formula, and includes the case where the FT synthesis reaction of formula 1 and the reverse water gas shift reaction shown in formula 3 below occur in parallel. In other words, Equation 2 is also a chemical reaction equation combining Equations 1 and 3.

[0026] The types of hydrocarbons produced at this time follow the ASF distribution based on the Anderson-Schulz-Flory (hereinafter referred to as "ASF") law. It is known that the composition of the hydrocarbons produced correlates with the value of the chain growth probability (α) in the FT synthesis reaction as shown in Equation 4. Here, W ｎ is the weight fraction of hydrocarbon products consisting of n carbon atoms in all hydrocarbons, and α is the chain growth probability.

[0027] The chain propagation probability (α) is expressed by the chain propagation rate (kp), which is the rate at which carbon chains increase in the FT synthesis reaction shown in FIG. 1, and the hydrolysis desorption rate (kd), which is the rate at which hydrocarbons on the catalyst surface are hydrogenated and desorbed (α=kp / (kp+kd)), and varies depending on the reaction conditions (temperature, pressure) of the FT synthesis reaction and the type of catalyst used.

[0028] As mentioned above, the FT synthesis reaction is a type of polymerization reaction, and it is generally difficult to keep the degree of polymerization (n number) constant. １ ~C １００＋ The carbon number distribution of hydrocarbons produced in the FT synthesis reaction follows the ASF distribution law and can be expressed by the chain growth probability (α) in this distribution law.

[0029] Figure 2 shows the relationship between the chain propagation probability (α) and the composition of hydrocarbons (crude product composition) produced by the FT synthesis reaction. As shown in Figure 2, hydrocarbons produced by the FT synthesis reaction contain multiple hydrocarbon compositions regardless of the value of the chain propagation probability (α).

[0030] In the conventional FT synthesis reaction, for example, the carbon number is mainly 8 to 16 (C ８ ~C １６ When attempting to obtain jet fuel fractions or kerosene / diesel fractions containing carbon atoms, the focus is on increasing the chain propagation probability (α) value and producing hydrocarbons with a larger carbon number. It is known that with conventional industrial catalysts, the chain propagation probability (α) value is approximately 0.85 to 0.95. In this case, it is possible to reduce the gas fraction (carbon number of 4 or less) contained in the product, but it is necessary to separate the wax from the product (Step 1) and upgrade the wax (hydrocracking and hydrotreating) (Step 2), and then distill the liquid hydrocarbons obtained in Step 1 and the hydrocracked and hydrotreated liquid hydrocarbons obtained in Step 2 to obtain the desired hydrocarbons with a carbon number of approximately 8 to 16 (C ８ ~C １６In other words, in order to obtain hydrocarbons having a specific carbon number such as SAF using conventional technologies, various processes (distillation, upgrading by hydrocracking and hydrotreating, etc.) are required for the product, which results in a large number of ancillary facilities and units constituting the plant, making on-site hydrocarbon production difficult. Therefore, in order to obtain useful saturated hydrocarbons selectively and simply, it is necessary to efficiently obtain hydrocarbons having a specific carbon number without reducing the efficiency of hydrocarbon production by the FT synthesis reaction. In other words, the CO conversion (or the ratio of CO and CO) in the FT synthesis reaction is important. ２ It is necessary to improve both the conversion rate and the selectivity for the carbon number of hydrocarbons (saturated hydrocarbons) obtained by the FT synthesis reaction.

[0031] As a result of extensive investigations, the present inventors have discovered that, with regard to a catalyst used in the FT synthesis reaction, the density of the active metal supported on the surface of the support is involved in improving the CO conversion rate, and further, that the density of the active metal supported on the surface of the support affects the value of the chain propagation probability (α) and is involved in improving the selectivity for producing hydrocarbons (saturated hydrocarbons) obtained by the FT synthesis reaction.

[0032] The Fischer-Tropsch synthesis catalyst (hereinafter also referred to as "FT synthesis catalyst") of the present invention and a method for producing the catalyst are based on the findings of the present inventors, and by using a catalyst for the FT synthesis reaction in which an active metal is supported on the surface of a support, and by supporting the active metal so that the metal density per specific surface area of ​​the support is within a specific range, it is possible to improve the CO conversion in the FT synthesis reaction and improve the selectivity of the carbon number of the resulting hydrocarbons (saturated hydrocarbons), and to more easily produce hydrocarbons having a specific carbon number, in particular saturated hydrocarbons useful as SAF. A specific composition of the FT synthesis catalyst as one embodiment of the present invention and a method for producing the same are described below.

[0033] [Fischer-Tropsch synthesis reaction catalyst (FT synthesis catalyst)] The FT synthesis catalyst in this embodiment functions as a catalyst in the FT synthesis reaction, and includes an active metal (hereinafter also referred to as a "main catalyst") that is the main component of the catalyst, a support (catalyst support) that supports the active metal, and an auxiliary catalyst.

[0034] Furthermore, the FT synthesis catalyst in this embodiment supports an active metal so that the metal density per specific surface area of ​​the support falls within a specific range. This not only improves the CO conversion rate in the FT synthesis reaction, but also makes it possible to suppress the production of hydrocarbons with a carbon number of 17 or more, which is greater than the carbon number (approximately 8 to 16) associated with saturated hydrocarbons useful as SAF, and to suppress the excessive production of hydrocarbons in the gas fraction (carbon number of 4 or less).

[0035] Additionally, the chain propagation probability (α) in the FT synthesis catalyst of this embodiment is preferably 0.65 to 0.85, more preferably 0.70 to 0.80, and most preferably 0.72 to 0.78. If the value is outside this range, the production efficiency of a hydrocarbon fraction (main component) corresponding to the carbon number (about 8 to 16 carbon atoms) of saturated hydrocarbons useful as SAF decreases.

[0036] The components and shape of the FT synthesis catalyst in this embodiment are described below. <Active Metal (Main Catalyst)> The active metal (main catalyst) of the FT synthesis catalyst in this embodiment is a metal catalyst selected from cobalt, ruthenium, and iron. Iron is inexpensive but has relatively low catalytic activity, while ruthenium has high catalytic activity but is an extremely expensive noble metal. Furthermore, the product of the FT synthesis reaction using an iron-based catalyst is characterized by a high naphtha content and also contains oxygen-containing compounds. For this reason, cobalt is most preferably used to obtain hydrocarbon fractions (so-called middle distillates) such as jet fuel, kerosene, and diesel, from the viewpoint of achieving both catalytic activity and cost.

[0037] Furthermore, the amount of active metal (main catalyst) is preferably 5% by weight or more and 25% by weight or less, expressed as the weight-based amount of active metal supported in the FT synthesis catalyst. It is more preferably 7.5% by weight or more and 20% by weight or less, and even more preferably 8% by weight or more and 15% by weight or less. An amount below this range tends to result in insufficient catalytic activity for the FT synthesis reaction, while an amount exceeding this range saturates the catalytic activity for the FT synthesis reaction, making the catalyst less technically significant, particularly in terms of cost.

[0038] As a result of extensive research, the present inventors have found that, with regard to catalysts used in the FT synthesis reaction, the CO conversion rate and the chain growth probability (α) are influenced not by the amount (supported amount) of the active metal present on the support, but by the density of the active metal on the support. In other words, they have discovered that the density of the active metal supported on the support surface is involved in improving the CO conversion rate, as well as in improving the selectivity for producing hydrocarbons (saturated hydrocarbons) obtained by the FT synthesis reaction. Based on this discovery, the active metal in this embodiment has a metal density per specific surface area of ​​the support that satisfies a specific range depending on the active metal. Specifically, when the active metal is cobalt, the metal density per specific surface area of ​​the support is 3 to 9.5 μmol / m ２ , preferably 4 to 8 μmol / m ２ When the active metal is ruthenium, the metal density per specific surface area of ​​the support is 0.3 to 2.5 μmol / m ２ , preferably 0.5 to 2.0 μmol / m ２ When the active metal is iron, the metal density per specific surface area of ​​the support is 5 to 15 μmol / m ２ By setting the carbon number within this range, it is possible to improve the selectivity for saturated hydrocarbons (carbon number of about 8 to 16) that are particularly useful as SAF, with regard to the carbon number of the hydrocarbons obtained by the FT synthesis reaction.

[0039] The finding that the density of the active metal on the support affects the CO conversion rate and the chain propagation probability (α) value in an FT synthesis catalyst is further explained below. When the density of the active metal on the support is low, the area of ​​direct contact between the support and the active metal increases, the interaction between the support and the active metal increases, and the oxidation state of the active metal increases. This is thought to suppress the hydrogenation ability of the active metal and promote chain propagation, which increases carbon chains, rather than hydrogenating and detaching hydrocarbons on the catalyst surface. On the other hand, when the density of the active metal on the support is high, the area of ​​direct contact between the support and the active metal decreases, reducing the interaction between the support and the active metal. However, a highly reduced state is achieved due to metallic bonding between the active metals. This is thought to increase the hydrogenation ability of the active metal and promote detachment due to hydrogenation during chain propagation, which increases carbon chains, on the catalyst surface. Therefore, the reaction system that proceeds predominantly on the catalyst surface varies depending on the density of the active metal on the support, which ultimately affects the CO conversion rate and the chain propagation probability (α) value in the FT synthesis catalyst.

[0040] <Carrier (catalyst carrier)> In this embodiment, a carrier containing silicon or aluminum is used as the carrier (catalyst carrier) of the FT synthesis catalyst. More specifically, silica (SiO ２ ), alumina (Al ２ O ３ ), zeolites (crystalline aluminosilicates), amorphous silica-alumina (SiO ２ -Al ２ O ３) is preferably used. Among these, it is particularly preferable to use a carrier containing silica. Silica is chemically stable and therefore does not easily affect the main catalyst or auxiliary catalyst. This allows the chemical properties of the main catalyst and auxiliary catalyst to be fully exhibited. Furthermore, since silica has a large specific surface area, it has high contact efficiency with the raw material gas (substrate), allowing the FT synthesis reaction to proceed efficiently. Furthermore, the true density (true specific gravity) of the carrier increases in the order of alumina > zeolite > silica. For example, in the production of hydrocarbons by the FT synthesis reaction, when a hydrocarbon production apparatus equipped with a bubble column as the FT synthesis reaction section described below is used, the smaller the true density (true specific gravity) of the carrier, the easier it is to disperse catalyst particles by bubbles, and therefore silica is considered to be the carrier with the best operability in this embodiment.

[0041] Furthermore, there are no particular limitations on the physical properties of the carrier (specific surface area, pore volume, average pore diameter, true density, bulk density). Below, from the viewpoint of improving the CO conversion rate, preferred numerical ranges for the physical properties of the carrier are exemplified, but the present invention is not limited to these. The specific surface area of ​​the carrier is preferably 200 to 450 m ２ / g, preferably 250 to 400 m ２ The pore volume of the carrier is 0.35 to 0.7 cm ３ / g, preferably 0.45 to 0.6 cm ３ The average pore diameter of the carrier is 4.5 to 8 Å, preferably 5 to 7.5 Å. The true density of the carrier is 1 to 5 g / cm ３ , preferably 2 to 4 g / cm ３ The bulk density of the carrier is 0.5 to 1.5 g / cm ３ , preferably 0.55 to 0.85 g / cm ３ Examples include:

[0042] <Auxiliary Catalyst> The FT synthesis catalyst in this embodiment may contain an auxiliary catalyst in addition to the main catalyst. Examples of the auxiliary catalyst include at least one selected from the group consisting of rare earth elements such as yttrium, cerium, lanthanum, praseodymium, neodymium, and holmium, at least one selected from the group consisting of alkali metals such as sodium, potassium, rubidium, and cesium, at least one selected from the group consisting of alkaline earth metals such as beryllium, magnesium, calcium, strontium, and barium, and at least one selected from the group consisting of copper, silver, molybdenum, and tungsten.

[0043] It is believed that the addition of an auxiliary catalyst to the FT synthesis catalyst in this embodiment increases the amount of carbon monoxide and carbon dioxide adsorbed on the catalyst surface and also increases the number of reaction active sites. In particular, when one selected from the group consisting of copper, silver, molybdenum, and tungsten is used, charge transfer occurs between the active metal (main catalyst) and the oxidation number of the main catalyst slightly decreases (δ-), and CO and CO ２ This is expected to have an effect of improving the reaction frequency (TOF (turnover frequency)) at the active site of the FT synthesis reaction, which is a type of hydrogenation reaction of the above. Furthermore, when one member is selected from the group consisting of copper, silver, molybdenum, and tungsten as the auxiliary catalyst, it is particularly preferable to select copper from the viewpoints of cost and the effect of improving the reaction frequency.

[0044] Furthermore, copper, silver, molybdenum, and tungsten can promote the water gas shift (WGS) reaction shown in the following formula 5. Therefore, in the raw material (feed) of the FT synthesis reaction, H ２ Even when the / CO ratio is low, the WGS reaction is promoted in the FT synthesis reaction, and H ２ The CO / CO ratio can be adjusted to a ratio favorable for hydrocarbon synthesis. In particular, excellent effects are achieved when the active metal (main catalyst) is cobalt or ruthenium. This enables fuel synthesis with a low hydrogen ratio (low hydrogen consumption).

[0045] Here, copper, silver, molybdenum, and tungsten are added to the raw materials (feeds) of the FT synthesis reaction. ２ When used to adjust the Cu-Co / SiO ratio, ２ It is possible to have the active metal present on a support like a catalyst, and also to use Cu / SiO ２ , Ag / SiO ２ , MoO Ｘ / SiO ２ , W.O. Ｘ / SiO ２ It is also preferable to use a mixture of a material in which an auxiliary catalyst component is supported on a carrier and the FT synthesis catalyst, as shown in the figure. It is more preferable to use a mixture of a Co-based FT synthesis catalyst and a Ru-based FT synthesis catalyst. In addition, Y-Co / SiO ２ Catalyst, K—Co / SiO ２ It is also preferable to mix it with an FT synthesis catalyst containing a co-catalyst, such as MoO Ｘ , WoO Ｘ The X value in the formula (1) is preferably less than 3. If the X value is 3, the promoting effect on the WGS reaction may decrease, which is not preferable.

[0046] In this embodiment, it is preferable to use at least one auxiliary catalyst selected from potassium, rubidium, and cesium, which suppresses carbon deposition in the FT synthesis reaction and thereby prevents catalyst deterioration, promotes chain growth, prevents the gas fraction (having 4 or less carbon atoms) from becoming excessive in the obtained hydrocarbons, and further improves the selectivity for the jet fuel (SAF) fraction containing hydrocarbons having about 8 to 16 carbon atoms.

[0047] When cobalt is used as the active metal, the auxiliary catalyst preferably contains at least one selected from yttrium, lanthanum, cerium, and holmium, with yttrium being particularly preferred. This enhances the dispersion of the active metal (cobalt) on the catalyst surface, increases the number of reaction active sites, and also reduces CO ２ Adsorption promotion and CO ２ This makes it possible to improve the conversion rate.

[0048] The amount of the auxiliary catalyst is preferably 1 / 30 to 1 / 3 of the weight of the active metal (main catalyst), and more preferably 1 / 20 to 1 / 5.

[0049] <Catalyst Shape> The FT synthesis catalyst in this embodiment is preferably in the form of a fine powder until the active metal is supported on the support, or when subjected to the FT synthesis reaction, from the viewpoint of the processing efficiency of the catalyst preparation and the reaction efficiency of the FT synthesis reaction. In this case, the size of the FT synthesis catalyst is preferably 0.07 mm or more and 0.2 mm or less. More preferably, it is 0.08 mm or more and 0.17 mm or less. The particle size of the catalyst can be measured by a laser diffraction method. This utilizes the phenomenon that when laser light is irradiated onto particles, scattering occurs, and the scattering angle becomes large for small particles and small for large particles.

[0050] On the other hand, the FT synthesis catalyst after the active metal is supported on the support is preferably formed into pellets. By forming the FT synthesis catalyst in this state, the surface area of ​​the catalyst before being subjected to the FT synthesis reaction can be reduced, and reoxidation of the catalyst (mainly the active metal) due to contact with air, etc. during storage or in subsequent steps related to catalyst preparation can be suppressed. This makes it possible to suppress a decrease in catalytic activity as an FT synthesis catalyst.

[0051] The means for forming the FT synthesis catalyst into pellets is not particularly limited, and examples thereof include tableting and extrusion. The FT synthesis catalyst in this embodiment is pulverized during the FT synthesis reaction. Therefore, when forming the FT synthesis catalyst into pellets, it is preferable to set the molding conditions (pressure, etc.) so that the catalyst is shaped to such an extent that subsequent pulverization is easy.

[0052] As described below, the FT synthesis catalyst is pretreated to activate the catalyst before being subjected to the FT synthesis reaction. The catalyst may be formed into pellets before the pretreatment, or may be formed into pellets after the pretreatment. From the viewpoints of improving operability and suppressing a decrease in catalytic activity, forming into pellets before the pretreatment is more preferable. When cobalt is used as the active metal, it is preferable to perform a stabilization treatment (stabilization step) described below in addition to the pellet-forming treatment (forming step). The order of the forming step and the stabilization step is not particularly limited. However, from the viewpoints of improving operability and suppressing a decrease in catalytic activity, it is preferable to perform the forming step and then the stabilization step. As described below, the stabilization step is included in the pretreatment related to catalyst activation. Therefore, when cobalt is used as the active metal, it is particularly preferable to perform the pretreatment related to catalyst activation (including the stabilization step) after the forming step.

[0053] [Preparation of FT synthesis catalyst] The manufacturing method (preparation method) of the FT synthesis catalyst in this embodiment preferably includes at least an active metal loading step of loading an active metal on the surface of a support, and further includes a forming step of forming the active metal into pellets and a stabilization step of performing a stabilization treatment. In addition, the active metal loading step preferably includes a metal density of the active metal per specific surface area of ​​the support of 3 to 9.5 μmol / m for cobalt. ２ , ruthenium: 0.3 to 2.5 μmol / m ２ , iron: 5 to 15 μmol / m ２ The active metal is supported on the surface of the carrier so that at least one of the following is selected. The preparation of the FT synthesis catalyst in this embodiment will be described below with specific examples.

[0054] <Preparation of Support Material> As described above, the support used in this embodiment contains silicon or aluminum. In particular, silica (SiO ２ ), alumina (Al ２ O ３ ), zeolites (crystalline aluminosilicates), amorphous silica-alumina (SiO ２ -Al ２ O３ It is preferable to use a carrier selected from at least one of the following: tetraethyl orthosilicate (TEOS, Si(O—C)), and it is particularly preferable to use a carrier containing silica. ２ H ５ ) ４ Alternatively, a method of preparing alumina by a sol-gel method in which an alcoholate (alkoxide) such as aluminum isopropoxide (Al(O-i-C)) is dissolved in an alcohol such as ethyl alcohol and polycondensed using an acid or base as a catalyst can be preferably used. ３ H ７ ) ３ In addition to the sol-gel method using alcoholates such as aluminum hydroxide (Al(OH) ３ ) in dry air. As for the zeolite, either natural or synthetic zeolite is preferred, and the framework structure can be preferably selected from A-type, Y-type, ZSM-type, etc. These zeolites can be treated with an acid (mineral acid) to produce various silica-aluminum ratios (SiO ２ / Al ２ O ３ For amorphous silica-alumina, silica (SiO ) can be impregnated by an impregnation method using an aqueous solution (impregnation liquid) of a water-soluble salt such as aluminum nitrate, or by an incipient wetness method (a method of filling pores with an impregnation liquid). ２ ) and calcining the mixture. Another preferred method involves thoroughly kneading silica powder and aluminum hydroxide in an automatic mortar or similar, followed by calcination. When kneading, dry mixing using only silica powder and aluminum hydroxide powder is acceptable, or it is also preferred to add water, water and a volatile organic solvent compatible with water, or a volatile organic solvent, such as water, water-ethanol, water-acetone, ethanol, or ethanol-isopropanol, and knead the mixture uniformly in a slurry state, dry, and then calcinate. The silica-aluminum ratio can be adjusted to any value by adjusting the concentrations of raw materials such as aluminum nitrate and aluminum hydroxide.

[0055] <Determination of saturated water absorption of support material> The support material is preliminarily heated and calcined (fired) at 500°C to 520°C for at least 3 hours under a dry air flow. After cooling to room temperature, highly pure water such as ion-exchanged water (hereinafter referred to as pure water) is added dropwise to a predetermined amount of support material using a burette or the like until the water absorption is saturated, and the water absorption per unit weight of the support material (ml (water) / g (support material)) is determined. Hereinafter, the saturated water supply amount will be referred to as ADF (adsorption factor). There is no particular upper limit to the firing time, but from the viewpoint of productivity, 6 hours can be considered the upper limit.

[0056] <Active metal raw material and auxiliary catalyst raw material> As the raw material (starting material) of the active metal and auxiliary catalyst, a water-soluble metal salt can be preferably used. For example, fluorides, chlorides, bromides, nitrates, sulfates, acetates, etc. can be preferably used. Of these, nitrates and acetates are preferred, and nitrates are most preferred.

[0057] <Supporting of Active Metal (Main Catalyst)> A specific example of the active metal support process for supporting an active metal on the support surface is described below. A support material previously calcined under dry air flow at 500°C to 520°C for at least 3 hours is cooled to room temperature, and a predetermined amount is precisely weighed out. A predetermined amount of active metal raw material is dissolved by adding pure water, and water is added until the ADF amount of the precisely weighed support material is reached, to prepare an impregnation solution. The precisely weighed support material is immersed in the impregnation solution and allowed to stand at room temperature. This is to ensure that the active metal is sufficiently impregnated into the interior of the support material. During the standing time, the active metal cations dissolved in water migrate (diffuse) into the interior of the support, aiming to more uniformly support the active metal. While there are no performance issues with a standing time of more than one hour, the effect of uniform support saturates, and the technical significance becomes diminished. As such, there is no upper limit to the standing time, but a period of one to two hours is substantially sufficient. In addition, the predetermined amounts of the carrier material and active metal raw material to be precisely weighed out at this time are as follows: Cobalt: 3 to 9.5 μmol / m as the metal density of the active metal per specific surface area of ​​the carrier ２ , ruthenium: 0.3 to 2.5 μmol / m ２ , iron: 5 to 15 μmol / m ２The impregnation temperature is set so that at least one of the following is selected. The obtained impregnation material is then dried under reduced pressure to remove moisture, and then calcined at 500°C for 3 hours in a dry air stream to obtain a catalyst precursor. When an auxiliary catalyst is used, pure water is added to a predetermined amount of active metal raw material and auxiliary catalyst raw material to dissolve them, and water is added until the amount reaches the ADF amount of the precisely weighed support material to prepare the impregnation solution. Other than this, the same treatment can be performed.

[0058] Furthermore, it is preferable to carry out the above-mentioned molding step (a step relating to molding into pellets) in this state of the catalyst precursor. The molded catalyst precursor may be stored until it is used in the FT synthesis reaction, or may be immediately transferred to the next step, which is the catalyst activation step. Note that when the molding step is carried out after the catalyst activation step (or stabilization step), the catalyst precursor is transferred to the next step (catalyst activation step) while remaining in the form of fine powder.

[0059] <Catalyst Activation Step> As a preparation step for the catalyst to start the reaction, the catalyst precursor is subjected to a series of pretreatment steps (catalyst activation steps) shown in the following (1) to (4) to activate the catalyst.

[0060] (1) Primary reduction Primary reduction is the reduction and activation of an oxidized catalyst. As a specific example of primary reduction, a catalyst precursor is placed in a fixed-bed atmospheric pressure flow reactor, and hydrogen is introduced at a gas hourly space velocity (GHSV) of 300 (v / v) h at a temperature of 400°C to 450°C. －１ More than 1500 (v / v)h －１ Examples include the following process including aeration and reduction.

[0061] (2) Stabilizing Catalyst Formation (Conversion into an Active Catalyst Precursor) Stabilizing catalyst formation (conversion into an active catalyst precursor) is a process (stabilization step) in which the primary reduced catalyst precursor is treated with an inert gas containing a small amount of oxidizing gas to promote partial oxidation of the active metal, thereby performing a stabilization treatment. The treatment time in stabilizing catalyst formation is 10 minutes or more and 200 minutes or less, more preferably 30 minutes or more and 100 minutes or less. When the active metal is cobalt, this stabilizing catalyst formation has the effect of making the conditions for the secondary reduction described below milder, and can be omitted when the active metal is ruthenium or iron. Here, the oxidizing gas includes hydrogen, oxygen, water vapor (H ２ O), carbon dioxide (CO ２ ), nitrous oxide (N ２ O), or a mixed gas thereof, can be preferably used, and from the viewpoint of handling, oxygen, water vapor, or carbon dioxide is more preferable. The amount of oxidizing gas contained in the inert gas is not particularly limited, but can be set to 0.05 to 20%. The amount of oxidizing gas is preferably selected according to the properties of each component, and for example, it is preferable to set the amount of oxidizing gas to 0.05 to 0.5% for oxygen, 0.5 to 2% for water vapor, 0.3 to 10% for carbon dioxide, and 1 to 20% for nitrous oxide. A specific example of the stabilized catalyst (active catalyst precursor) is a mixture of an inert gas (He, N) containing 0.1% oxygen at a temperature of 25°C to 50°C. ２ etc.) at GHSV 300 (v / v) h －１ More than 600 (v / v)h －１ Examples of such a process include a process for passing an inert gas through the catalyst for 1 hour to 3 hours to obtain a stabilized catalyst (active catalyst precursor). Furthermore, by passing an inert gas through the catalyst so that the initial temperature rise rate is 0.01 to 1.0°C / min, partial oxidation (stabilization treatment) of the active metal can proceed smoothly.

[0062] (3) Catalyst Packing Catalyst packing refers to packing a catalyst into a reactor. Here, the reactor is the location where the FT synthesis reaction takes place, and in this embodiment, corresponds to the FT reactor 2 (slurry bed bubble column reactor) in the hydrocarbon production apparatus 1 described below. A specific example of catalyst packing involves adding the stabilizing catalyst to a dispersion medium (corresponding to the medium oil 5 in the hydrocarbon production apparatus 1 described below) made of liquid hydrocarbon components to form a slurry. Next, hydrogen and a hydrogen-steam mixed gas are supplied from the bottom of the reactor, and this slurry is introduced into the reactor in a bubble-generating state. Note that if the catalyst precursor is formed into pellets, the stabilizing catalyst will also be formed into pellets. Therefore, when forming a slurry, it is preferable to add the pellet-shaped stabilizing catalyst to the dispersion medium and then use a homogenizer or the like to refine and disperse the formed body.

[0063] (4) Secondary Reduction Secondary reduction refers to activating a catalyst by heating while passing a reducing gas through it. Preferred reducing gases include hydrogen, a hydrogen-steam mixed gas, and carbon monoxide. Hydrogen and a hydrogen-steam mixed gas are more preferred, with hydrogen being even more preferred. It is not prohibited to simultaneously supply an inert gas, such as nitrogen or a rare gas, to the reducing gas. This secondary reduction can proceed under milder conditions (temperature of around 200°C) than the reduction conditions in the primary reduction (temperature of 400 to 450°C). This offers the advantage that the reactor in the FT synthesis reaction can also be used to carry out part of the pretreatment process related to catalyst activation. A specific example of secondary reduction involves supplying hydrogen and the hydrogen-steam mixed gas described above in (3) while maintaining the reactor pressure at a pressure in the range of 300 kPa to 600 kPa, raising the reactor temperature to a range of 150°C to 250°C in a bubbling state, and maintaining this temperature for 1 hour to 3 hours.

[0064] The FT synthesis catalyst obtained through the above-mentioned steps is a catalyst in which an active metal is supported on the surface of a support, and the active metal is supported so that the metal density per specific surface area of ​​the support is within a specific range. This improves the CO conversion rate in the FT synthesis reaction and improves the selectivity of the carbon number of the resulting hydrocarbons (saturated hydrocarbons), making it possible to more easily produce hydrocarbons with a specific carbon number, particularly saturated hydrocarbons useful as SAF.

[0065] The hydrocarbon production apparatus and hydrocarbon production method of the present invention use the FT synthesis catalyst of the present invention, which can improve the CO conversion in the FT synthesis reaction and the carbon number selectivity of the resulting hydrocarbons (saturated hydrocarbons), to proceed with the FT synthesis reaction and obtain hydrocarbons. This makes it possible to reduce the facilities and equipment that make up a plant for producing hydrocarbons by the FT synthesis reaction and to more easily obtain hydrocarbons having a specific carbon number (particularly saturated hydrocarbons useful as SAF). Below, a hydrocarbon production apparatus as one embodiment of the present invention will be described using a specific example. As mentioned above, the description of the hydrocarbon production method as an embodiment of the present invention shall be replaced with the description of the configuration and operation of the hydrocarbon production apparatus shown in the embodiment below.

[0066] [Hydrocarbon Production Apparatus] The hydrocarbon production apparatus in this embodiment is an apparatus for producing hydrocarbons by an FT synthesis reaction using the above-mentioned FT synthesis catalyst. More specifically, the hydrocarbon production apparatus in this embodiment supplies a raw material gas into a reaction vessel having a reaction catalyst (the FT synthesis catalyst of this embodiment) and carries out the FT synthesis reaction.

[0067] Fig. 3 is a schematic explanatory diagram of a hydrocarbon production apparatus in an embodiment of the present invention. As shown in Fig. 3, the hydrocarbon production apparatus 1 in this embodiment may include an FT reactor 2 as an FT synthesis reaction section, and a heat exchanger 3. Each component of the hydrocarbon production apparatus 1 in this embodiment and its operation (action) will be described below.

[0068] <FT synthesis reaction section> The FT synthesis reaction section is for progressing the FT synthesis reaction, and supplies a raw material gas 4 into a reaction vessel (FT reactor 2 in this embodiment) having a reaction catalyst (FT synthesis catalyst of this embodiment, hereinafter referred to as "FT synthesis catalyst C"), and carries out the FT synthesis reaction based on the above-described formulas 1 to 3.

[0069] <FT Reactor> Examples of the FT reactor in this embodiment include a slurry fluidized bed reactor based on a gas-liquid catalytic reaction and a fixed bed reactor based on a gas-solid catalytic reaction. Fixed bed reactors are known to have high reaction yields. On the other hand, slurry reactors have high temperature controllability and are preferably used as the FT reactor 2 in this embodiment. One of the most preferred forms of the FT reactor 2 related to the FT synthesis reaction section in this embodiment is a slurry bed bubble column reactor (SBCR). Hereinafter, the FT reactor 2 in this embodiment will be described as having a configuration related to an SBCR, but is not limited to this. For example, in addition to the SBCR, reactors based on known reaction types such as a circulating fluidized bed (CFB) reactor, a fluidized bed reactor, and a fixed bed reactor can be used.

[0070] A specific example of the FT reactor 2 in this embodiment is a pressure-resistant vessel for use in a gas-liquid contact reaction, which has a structure in which the interior is filled with liquid, gas is blown in from the bottom, and the reaction proceeds at the gas-liquid interface. Furthermore, a liquid hydrocarbon medium oil 5 containing a fine powder of FT synthesis catalyst C is used as the liquid to fill the FT reactor 2, and the reaction proceeds by blowing in fine bubbles of feed gas 4 from the bottom of the FT reactor 2. A gas distributor 2a is installed at the bottom of the FT reactor 2 to convert the feed gas 4 into fine feed gas bubbles 4a.

[0071] <Medium Oil> The medium oil 5 is a liquid medium that suspends the FT synthesis catalyst C and fills the FT reactor 2 for the gas-liquid contact reaction. As the medium oil 5, for example, a liquid hydrocarbon is used, and it is preferable to use a paraffinic liquid hydrocarbon having 10 to 20 carbon atoms. The FT synthesis catalyst C described above is suspended in this in the form of a fine powder. As described above, this medium oil 5 can be the same as the dispersion medium used in (3) Catalyst Packing in the FT synthesis catalyst pretreatment step (catalyst activation step). As the FT synthesis reaction progresses, the medium oil 5 in the FT reactor 2 is replaced with hydrocarbons (FT oil) synthesized in the FT synthesis reaction.

[0072] In the hydrocarbon production apparatus 1 of this embodiment, the means for containing (filling) the FT synthesis catalyst C in the FT reactor 2 is introduced into the FT reactor 2 together with the medium oil 5. Therefore, it is preferable to adjust the amount of FT synthesis catalyst C (filled catalyst amount) filled into the FT reactor 2 as follows. First, a slurry is prepared by adding the FT synthesis catalyst C (before catalyst activation) in an amount equal to or less than half the weight of the medium oil 5 to the medium oil 5. Next, the slurry is introduced and adjusted so that the amount of filled catalyst is 2% by weight or more and 25% by weight or less relative to the total amount of medium oil 5 initially filled into the FT reactor 2. The amount of filled catalyst is more preferably 5% by weight or more and 20% by weight or less, and even more preferably 7% by weight or more and 12% by weight or less.

[0073] <Feedstock Gas> The feedstock gas 4 is a raw material for producing hydrocarbons by the FT synthesis reaction. As described above, in a normal FT synthesis reaction, the feedstock gas 4 contains carbon monoxide (CO) and hydrogen (H ２ ), but in this embodiment, the raw material gas 4 is made of a mixed gas of carbon dioxide (CO ２ In particular, when the auxiliary catalyst in the FT synthesis catalyst C contains one selected from the group consisting of copper, silver, molybdenum, and tungsten, CO ２ Since the shift from CO to CO is promoted, the FT synthesis reaction can be efficiently carried out even when the raw material gas 4 contains carbon dioxide.

[0074] Regarding the raw material gas 4, the rate of the FT synthesis reaction depends on the hydrogen partial pressure. ２ A partial pressure is required, and the partial pressure ratio (molar ratio) of hydrogen to the total (carbon monoxide + carbon dioxide) in the feed gas 4 is suitably 0.6 to 2.7, preferably 0.8 to 2.5, and more preferably 1.0 to 2.3. The ratio of carbon monoxide to carbon dioxide can be varied depending on the purpose: the carbon dioxide ratio is increased for the purpose of carbon recycling, and the carbon monoxide ratio is increased for the purpose of increasing the conversion rate to hydrocarbons. When both are used in combination, the ratio of carbon dioxide to carbon monoxide is not particularly limited, but the proportion of carbon dioxide relative to the total amount of carbon monoxide and carbon dioxide must be 1% by volume or more, preferably 10% by volume or more, more preferably 30% by volume or more, and even more preferably 40% by volume or more. Furthermore, as other components, substances other than the above-mentioned hydrogen, carbon monoxide, and carbon dioxide may be mixed into the feed gas as long as they do not interfere with the FT synthesis reaction.

[0075] <Products> Of the hydrocarbon mixture that is the product produced by the FT synthesis reaction, a gas / volatile oil fraction (light fraction 6b) having a small carbon number is extracted as a gas from the top of the FT reactor 2. On the other hand, a liquid / solid hydrocarbon fraction (jet fuel, kerosene / diesel fraction, or one containing a wax fraction, middle distillate 6a) having a large carbon number is extracted from the top below the liquid level of the FT reactor 2 and appropriately fractionated and refined. Note that in the hydrocarbon production apparatus 1 of this embodiment, by using the above-mentioned FT synthesis catalyst C, it is possible to significantly reduce the proportion of solid hydrocarbon fraction (wax fraction) contained in the middle distillate 6a. This eliminates the need for upgrading by hydrocracking and hydrotreating, which has conventionally been required when producing hydrocarbons having a specific carbon number, particularly saturated hydrocarbons useful as SAF, and makes it possible to reduce the amount of ancillary equipment that constitutes the plant.

[0076] <Heat Exchanger> The heat exchanger 3 is intended to maintain the temperature within the FT reactor 2 within a predetermined range. Since the FT synthesis reaction is an exothermic reaction, it is necessary to install a heat exchanger 3 with excellent heat exchange capacity in the FT reactor 2. As this heat exchanger 3, a tubular or coil-shaped cooling pipe is generally used. However, as shown in Figure 3, a suitable example is a heat exchanger having a structure in which a large number of plate-shaped cooling plates, each having an uneven surface to increase the heat transfer surface area, are closely stacked together in the FT reactor 2. In this case, cooling water 3a introduced from the bottom of the FT reactor 2 passes through the cooling plates of the heat exchanger 3 and becomes heated steam 3b from the top and exits the system. In addition to the heat exchanger 3 inside the FT reactor 2, a heat exchange jacket can be installed outside the FT reactor 2 to use external cooling in combination.

[0077] <Other Configurations> In the hydrocarbon production apparatus 1 of this embodiment, the feedstock gas 4 is dispersed in the medium oil 5 (liquid hydrocarbon) as bubbles and moves upward, forming an upward flow of liquid hydrocarbons. The upward flow and buoyancy cause the FT synthesis catalyst C to be dispersed within the bubble column in the FT reactor 2. For this reason, in addition to dispersing the FT synthesis catalyst C by the upward flow and buoyancy of the bubbles, a stirring mechanism can also be provided for the FT reactor 2. In this case, it is also preferable to provide the stirring mechanism with stirring blades for forced dispersion. The provision of stirring blades increases the contact efficiency between the feedstock gas 4 (gas), medium oil 5 (liquid), and FT synthesis catalyst C (solid), allowing the height of the reaction column of the FT reactor 2 to be reduced, thereby saving space in the plant. In this case, it is preferable to provide the heat exchanger 3 outside the FT reactor 2.

[0078] <FT Reaction Temperature (Slurry Bed Temperature) and Reaction Pressure> The slurry bed in the FT reactor 2 is maintained at a temperature of 200°C or higher and 270°C or lower, and at a pressure of 0.5 MPa.G or higher and 3 MPa.G or lower. The reaction temperature is preferably 200°C or higher and 270°C or lower, more preferably 210°C or higher and 240°C or lower, and even more preferably 220°C or higher and 240°C or lower. Below these temperatures, CO and CO ２The conversion rate is low, resulting in low productivity. On the other hand, if the temperature exceeds this range, the gas components consisting of low-carbon number hydrocarbons (e.g., methane to butane) will increase, and the hydrocarbon yield (SAF yield) that satisfies the target carbon number will saturate. The reaction pressure is preferably 0.5 MPa·G to 3 MPa·G, more preferably 0.5 MPa·G to 2 MPa·G, and most preferably 0.6 MPa to 1.5 MPa·G. Below this pressure range, chain growth tends to be difficult, and the SAF yield may decrease. On the other hand, if the pressure exceeds this range, chain growth will saturate, and the unit consumption will increase due to compression, thereby diminishing the technical significance.

[0079] According to the hydrocarbon production method and hydrocarbon production apparatus of this embodiment, the wax upgrading step and distillation step can be omitted or simplified, and the saturated hydrocarbon fraction useful as SAF can be efficiently produced (recovered). This makes it possible to efficiently produce (recover) saturated hydrocarbon fractions useful as SAF on-site, more specifically, in a CO2 facility adjacent to an airport, for example. ２ This will enable SAF production at recovery sites and hydrogen production sites, contributing to the spread of carbon-neutral fuels.

[0080] The present invention will be explained in more detail below by showing examples and comparative examples relating to hydrocarbon production using the FT synthesis catalyst and hydrocarbon production apparatus of the present invention. Note that the present invention is not limited to the examples shown below.

[0081] First, catalysts A to C shown in Table 1 were prepared as examples relating to the relationship between the metal density of the active metal per specific surface area of ​​the support in an FT synthesis catalyst (active metal density on the support) and the product distribution when an FT synthesis reaction is carried out. Catalysts A to C differ only in the density of the active metal on the support, and have the same constituent components. Catalysts A to C in this example use cobalt as the active metal and silica as the support.

[0082]

[0083] These catalysts A to C were applied to the hydrocarbon production apparatus 1 described above to carry out an FT synthesis reaction. The reaction conditions were a reaction temperature of 230°C, a pressure of 0.6 MPa, G, and a catalyst loading (slurry concentration) of 5 (w / v)% packed into the FT reactor 2. A feed gas consisting of a mixed gas of carbon monoxide and hydrogen was supplied at 6 L / h to carry out the FT synthesis reaction. The resulting products (middle fraction 6a and light fraction 6b) were recovered and identified by gas chromatography. The results are shown in FIG. 4. Furthermore, the conversion, chain growth probability, and reaction frequency were calculated as values ​​relating to the catalytic performance of catalysts A to C. The results are shown in Table 1.

[0084] FIG. 4 is a graph showing the relationship between the on-support density of the active metal and the product distribution when the FT synthesis reaction is performed in this example, with the horizontal axis representing the carbon number and the vertical axis representing the weight distribution of hydrocarbons in the product. Note that FIG. 4A is a graph for light fractions with carbon numbers of 1 to 5, and FIG. 4B is a graph for light fractions and middle fractions with carbon numbers of 6 to 16. As shown in FIG. 4 , for products produced by the FT synthesis reaction with carbon numbers of 1 to 6, the weight distribution of the product increases as the on-support density of the active metal increases. On the other hand, for products with carbon numbers of 7 to 16, the weight distribution of the product decreases as the on-support density of the active metal increases. In other words, it was shown that the on-support density of the active metal is involved in improving the selectivity of the production of hydrocarbons (saturated hydrocarbons) obtained by the FT synthesis reaction. Additionally, as shown in Table 1, it was shown that the on-support density of the active metal affects not only the CO conversion rate and the chain growth probability (α) but also the reaction frequency.

[0085] Next, FT synthesis catalysts according to Examples 1 to 8 and Comparative Examples 1 to 3 were prepared based on the compositions and physical properties shown in Table 2, and were applied to the hydrocarbon production apparatus 1 to carry out the FT synthesis reaction. In both Examples and Comparative Examples, cobalt was used as the active metal and silica was used as the carrier. The reaction conditions were a reaction temperature of 230°C, a pressure of 0.5 to 0.7 MPa, G, and a mixed gas of carbon monoxide and hydrogen (H ２A feed gas consisting of a sulphur dioxide (CO) ratio of 1.96 (H2O) was supplied at 6 L / h to carry out the FT synthesis reaction. The conditions for the amount of catalyst packed (slurry concentration) into the FT reactor 2 are shown in Table 2. The products generated (recovered) were evaluated for suitability as jet fuel or kerosene / diesel fractions. The results are shown in Table 2.

[0086]

[0087] As shown in Table 2, when the density of the active metal on the carrier is a predetermined value (cobalt: 3 to 9.5 μmol / m ２ In the FT synthesis reaction using the FT synthesis catalysts of Examples 1 to 8 that satisfied the above conditions, the obtained products were suitable for use as jet fuel or kerosene / diesel fractions. On the other hand, in Comparative Example 1, in which the density of the active metal on the support exceeded a predetermined value, the obtained products had an excess of gas components, and in Comparative Examples 2 and 3, in which the density of the active metal on the support was below the predetermined value, the obtained products had an excess of heavy components (hydrocarbons having 17 or more carbon atoms). In other words, it was found that when the FT synthesis catalysts of Comparative Examples 1 to 3 were used, all of the obtained products were unsuitable for use as jet fuel or kerosene / diesel fractions.

[0088] Furthermore, FT synthesis catalysts according to Example 9 and Comparative Example 4 were prepared based on the compositions and physical properties shown in Table 3, and were applied to the hydrocarbon production apparatus 1 to carry out the FT synthesis reaction. In both the Examples and Comparative Examples, cobalt was used as the active metal and silica was used as the carrier. Here, Example 9 contains copper as the auxiliary catalyst, while Comparative Example 4 does not contain copper as the auxiliary catalyst. The reaction conditions at this time were a reaction temperature of 230°C, a pressure of 0.5 to 0.7 MPa, G, and a mixed gas of carbon monoxide and hydrogen (H ２ A feed gas consisting of 79.7% CO (CO ratio: 1.96) and 20.3% carbon dioxide was supplied at a rate of 6 L / h to carry out the FT synthesis reaction. The conditions for the amount of catalyst (slurry concentration) packed into the FT reactor 2 are shown in Table 3. The products generated (recovered) were evaluated for suitability as jet fuel or kerosene / diesel fractions. The results are shown in Table 3.

[0089]

[0090] As shown in Table 3, when the density of the active metal on the carrier is a predetermined value (cobalt: 3 to 9.5 μmol / m ２ In the FT synthesis reaction using the FT synthesis catalyst of Example 9, which satisfied the above conditions and contained copper as an auxiliary catalyst, even when a feed gas containing carbon dioxide was used, the resulting product was suitable for use as jet fuel or a kerosene / light oil fraction. On the other hand, in Comparative Example 4, which satisfied the specified on-carrier density of the active metal but did not contain copper as an auxiliary catalyst, it was found that when a feed gas containing carbon dioxide was used, the resulting product had an excessive gas content and was unsuitable for use as jet fuel or a kerosene / light oil fraction. Therefore, it was demonstrated that the FT synthesis catalyst of this embodiment, by setting the on-carrier density of the active metal to a specified value and selecting and containing an appropriate auxiliary catalyst, can efficiently convert a feed gas containing carbon dioxide into desired hydrocarbons.

[0091] The above-described embodiments show examples of a Fischer-Tropsch synthesis reaction catalyst, a method for producing the catalyst, and a hydrocarbon production apparatus and method. The Fischer-Tropsch synthesis reaction catalyst, a method for producing the catalyst, and a hydrocarbon production apparatus and method according to the present invention are not limited to the above-described embodiments, and may be modified within the scope of the gist of the claims.

[0092] The Fischer-Tropsch synthesis catalyst and the method for producing the catalyst of the present invention can be used as a technology that can selectively and easily produce hydrocarbons (saturated hydrocarbons) having a specific carbon number, and is particularly suitable for use in the production of carbon-neutral fuels (kerosene, diesel, and SAF).

[0093] Furthermore, the hydrocarbon production method and hydrocarbon production apparatus of the present invention can be used as a technology that enables simple on-site production of hydrocarbons (saturated hydrocarbons) having a specific carbon number, and is particularly suitable for use in the production of carbon-neutral fuels (kerosene, diesel, and SAF).

[0094] 1 Hydrocarbon production equipment, 2 FT reactor, 2a Gas distributor, 3 Heat exchanger, 3a Cooling water, 3b Heating steam, 4 Feed gas, 4a Feed gas bubbles, 5 Medium oil, 6a Middle distillate, 6b Light distillate, CFT synthesis catalyst

Claims

1. A catalyst for use in a Fischer-Tropsch synthesis reaction, comprising a support surface on which an active metal is supported, the support containing silicon or aluminum, the active metal containing at least one selected from cobalt, ruthenium, and iron, and the metal density per specific surface area of ​​the support being: cobalt: 3 to 9.5 μmol / m ２ , ruthenium: 0.3 to 2.5 μmol / m ２ , iron: 5 to 15 μmol / m ２ 1. A catalyst for a Fischer-Tropsch synthesis reaction, comprising at least one selected from the group consisting of:

2. The Fischer-Tropsch synthesis catalyst according to claim 1, further comprising at least one element selected from the group consisting of potassium, rubidium, and cesium.

3. The Fischer-Tropsch synthesis catalyst according to claim 1, wherein the active metal is cobalt and the catalyst contains at least one element selected from the group consisting of yttrium, lanthanum, cerium, and holmium.

4. The Fischer-Tropsch synthesis catalyst according to claim 1, which is formed into pellets.

5. A method for producing a catalyst used in a Fischer-Tropsch synthesis reaction, comprising an active metal supporting step of supporting an active metal on a support surface, wherein the support contains silicon or aluminum, and the active metal contains at least one selected from cobalt, ruthenium, and iron, and the active metal supporting step is carried out by carrying out the following as a metal density of the active metal per specific surface area of ​​the support: cobalt: 3 to 9.5 μmol / m ２ , ruthenium: 0.3 to 2.5 μmol / m ２ , iron: 5 to 15 μmol / m ２ 10. A method for producing a catalyst for a Fischer-Tropsch synthesis reaction, comprising supporting the active metal on the surface of the carrier so that at least one of the following is selected:

6. A method for producing a catalyst for a Fischer-Tropsch synthesis reaction according to claim 5, characterized in that after the active metal supporting step, a forming step of forming the catalyst into pellets and a stabilization step of carrying out a stabilization treatment are further included.

7. A hydrocarbon production apparatus for producing hydrocarbons by a Fischer-Tropsch synthesis reaction by supplying a raw material gas into a reaction vessel containing a reaction catalyst, wherein the reaction catalyst is a Fischer-Tropsch synthesis reaction catalyst according to any one of claims 1 to 4.

8. The hydrocarbon production apparatus according to claim 7, wherein the raw material gas contains carbon dioxide.

9. A hydrocarbon production method in which a raw material gas is supplied into a reactor containing a reaction catalyst to produce hydrocarbons by a Fischer-Tropsch synthesis reaction, characterized in that the Fischer-Tropsch synthesis catalyst according to any one of claims 1 to 4 is used as the reaction catalyst.

10. The hydrocarbon production method according to claim 9, wherein the feed gas contains carbon dioxide.

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