Method for producing hydrocarbon, device for producing hydrocarbon, and system for producing hydrocarbon

Abstract

Provided is a method for producing a hydrocarbon, said method comprising: a film removal step for removing a passivation film from a catalyst; and a generation step for generating a hydrocarbon using a Fischer–Tropsch reaction, by reacting, in the presence of the catalyst from which the passivation film was removed in the film removal step, a raw material gas containing hydrogen gas and carbon monoxide gas.

Description

Hydrocarbon production method, hydrocarbon production apparatus, and hydrocarbon production system

[0001] The present invention relates to a method for producing hydrocarbons, an apparatus for producing hydrocarbons, and a system for producing hydrocarbons.

[0002] Patent Document 1 discloses a technology for producing hydrocarbons by the Fischer-Tropsch process (hereinafter also referred to as the "FT process"). In the FT process, carbon monoxide (CO) and hydrogen (H) are used. ２ A raw material gas containing ) is brought into contact with a catalyst to synthesize hydrocarbons. The hydrocarbon synthesis reaction by the FT method is also called the "FT reaction."

[0003] International Publication No. 2024 / 111562

[0004] To prevent catalysts from being oxidized and deactivated by exposure to the atmosphere before use in FT synthesis, passivation treatment is sometimes applied to the catalyst. Traditionally, passivated catalysts have been used directly in the FT reaction, but this method had room for improvement in the carbon monoxide conversion rate. Furthermore, hydrocarbons obtained by the FT reaction are attracting attention as SAF (Sustainable Aviation Fuel), but it has been difficult to obtain long-chain hydrocarbons suitable for aviation fuel with high selectivity using methods that directly utilize passivated catalysts in the FT reaction.

[0005] In view of the above, the present invention provides a technology that can produce long-chain hydrocarbons with a high carbon monoxide conversion rate and high selectivity.

[0006] The present invention encompasses the following embodiments: [1] A method for producing hydrocarbons, comprising: a film removal step of removing a passive film from a catalyst; and a production step of reacting a raw material gas containing hydrogen gas and carbon monoxide gas by a Fischer-Tropsch reaction in the presence of the catalyst from which the passive film has been removed in the film removal step to produce hydrocarbons. [2] The method for producing hydrocarbons according to [1], wherein in the film removal step, the passive film is removed by a reduction reaction. [3] The method for producing hydrocarbons according to [2], wherein in the film removal step, the passive film is removed by supplying a reducing gas to a slurry containing the catalyst and a first organic solvent. [4] The method for producing hydrocarbons according to [3], wherein the reducing gas contains hydrogen gas. [5] The method for producing hydrocarbons according to any one of [1] to [4], wherein in the production step, hydrocarbons are produced by a slurry bed method using a second organic solvent. [6] The method for producing hydrocarbons according to [5], wherein the second organic solvent is a liquid hydrocarbon. [7] The method for producing hydrocarbons according to [5] or [6], wherein the boiling point of the second organic solvent is 200°C or higher. [8] The method for producing hydrocarbons according to any one of [1] to [7], wherein the film removal step and the production step are performed using the same equipment. [9] The method for producing hydrocarbons according to any one of [1] to [8], wherein the catalyst comprises at least one catalytic metal selected from the group consisting of cobalt, nickel, ruthenium, and iron.

[10] The method for producing hydrocarbons according to [9], wherein the catalyst comprises the catalytic metal and a carrier supporting the catalytic metal.

[11] The method for producing hydrocarbons according to

[10] , wherein the carrier comprises silica.

[12] The method for producing hydrocarbons according to any one of [9] to

[11] , wherein the catalytic metal comprises cobalt.

[13] A hydrocarbon production apparatus comprising: a film removal unit for removing a passive film from a catalyst; a reactor for producing hydrocarbons by reacting a raw material gas containing hydrogen gas and carbon monoxide gas in the presence of the catalyst from which the passive film has been removed by the film removal unit via a Fischer-Tropsch reaction; and a raw material gas supply unit for supplying the raw material gas to the reactor.

[14] The hydrocarbon production apparatus according to

[13] , wherein the film removal unit is a reducing gas supply unit that supplies a reducing gas for reducing the passivation film to the reactor.

[15] A hydrocarbon production system comprising the hydrocarbon production apparatus according to

[13] or

[14] and a raw material gas generator that generates the raw material gas.

[16] The hydrocarbon production system according to

[15] , wherein the raw material gas generator comprises a combustion device and a reverse shift reactor that generates the raw material gas from a mixed gas discharged from the combustion device.

[0007] According to the present invention, it is possible to provide a technology that can produce long-chain hydrocarbons with a high carbon monoxide conversion rate and high selectivity.

[0008] Figure 1 is a schematic diagram showing an example of a hydrocarbon manufacturing apparatus. Figure 2 is a schematic diagram showing another example of a hydrocarbon manufacturing apparatus. Figure 3 is a schematic diagram showing the steps of a hydrocarbon manufacturing method. Figure 4 is a schematic diagram showing the steps of a hydrocarbon manufacturing method. Figure 5 is a schematic diagram showing the steps of a hydrocarbon manufacturing method. Figure 6 is a schematic diagram showing the steps of a hydrocarbon manufacturing method. Figure 7 is a schematic diagram showing the steps of a hydrocarbon manufacturing method. Figure 8 is a schematic diagram showing the steps of a hydrocarbon manufacturing method. Figure 9 is a schematic diagram showing the steps of a hydrocarbon manufacturing method. Figure 10 is a schematic diagram showing the steps of a hydrocarbon manufacturing method. Figure 11 is a schematic diagram showing the steps of a hydrocarbon manufacturing method. Figure 12 is a block diagram showing an example of a hydrocarbon manufacturing system.

[0009] Hereinafter, embodiments for carrying out the present invention (hereinafter also referred to as "this embodiment") will be described in detail with reference to the drawings as appropriate. The following embodiments are illustrative examples for explaining the present invention and are not intended to limit the present invention to the following content. The present invention can be carried out by modifying it as appropriate within the scope of its gist. In addition, although the explanation may be given with reference to the drawings, the same or equivalent elements in each drawing will be denoted by the same reference numeral, and redundant explanations will be omitted. Unless otherwise specified, the positional relationships such as up, down, left, and right in the drawings are based on the positional relationships shown in the drawings. Furthermore, the dimensional ratios of each component explained in the drawings are not limited to the ratios shown.

[0010] [Hydrogen Production Apparatus] Figure 1 is a schematic diagram showing an example of the hydrocarbon production apparatus 10 of this embodiment (hereinafter also simply referred to as "production apparatus 10"). Figure 2 is a schematic diagram showing another example of the hydrocarbon production apparatus 10 of this embodiment.

[0011] As shown in Figures 1 and 2, the manufacturing apparatus 10 includes a reactor 11 that generates hydrocarbons by reacting a raw material gas 33 containing hydrogen gas and carbon monoxide gas in a Fischer-Tropsch reaction (FT reaction) in the presence of a catalyst 20 from which the passive film 21 has been removed by a film removal unit 14 described later.

[0012] Reactor 11 can be appropriately designed to serve as the reaction site for the FT reaction. For example, reactor 11 can be a heat-resistant and pressure-resistant vessel configured to withstand the reaction conditions of the FT reaction. The capacity of reactor 11 is not particularly limited, but is, for example, 1000 L or less. Reactor 11 may be a slurry bed reactor as shown in Figures 1 and 2, or it may be another type of reactor such as a fixed bed reactor or a fluidized bed reactor capable of producing hydrocarbons by the FT method.

[0013] If reactor 11 is a slurry-bed reactor, reactor 11 contains a slurry 30 containing catalyst 20 and second organic solvent 32, and the FT reaction is a gas-liquid catalytic reaction. Such a reaction is also called a slurry-bed reaction. The raw material gas 33 usually has a lower specific gravity than the slurry 30, and when it is blown into the slurry 30, it moves upward within the slurry 30. In this way, as the raw material gas 33 passes through the slurry 30 in reactor 11, the raw material gas 33 comes into contact with the catalyst 20 in the slurry 30, and the FT reaction proceeds. Details of catalyst 20 and second organic solvent 32 will be described later.

[0014] As shown in Figures 1 and 2, the manufacturing apparatus 10 includes a raw material gas supply unit 12 that supplies raw material gas 33 containing hydrogen gas and carbon monoxide gas to the reactor 11. The raw material gas supply unit 12 may be connected to the reactor 11 via a raw material gas supply pipe 13. It is preferable that the raw material gas supply unit 12 supplies the raw material gas 33 from the bottom of the reactor 11. Here, "bottom of the reactor 11" includes the bottom of the reactor 11 and a part of the side of the reactor 11. The raw material gas 33 usually moves upward through the slurry 30 due to the difference in specific gravity between it and the slurry 30. Therefore, when the raw material gas 33 is supplied from the bottom of the reactor 11, it tends to be possible to ensure a sufficient distance for the raw material gas 33 to move within the slurry 30. As a result, the catalyst 20 and the raw material gas 33 tend to come into contact efficiently. Furthermore, from the viewpoint of reducing the occurrence of dead spaces that are difficult for the raw material gas 33 to reach, it is preferable that the raw material gas supply unit 12 supplies the raw material gas 33 from the bottom of the reactor 11. When the raw material gas supply unit 12 supplies the raw material gas 33 from the side of the slurry bed type reactor 11, it is preferable that the raw material gas supply pipe 13 is connected at a position no more than 1 / 3 of the liquid level of the slurry 30.

[0015] The raw material gas supply unit 12 may be configured to store the raw material gas 33 when the FT reaction is not being carried out and to supply the raw material gas 33 to the reactor 11 when the FT reaction is being carried out. The raw material gas supply unit 12 may also be equipped with flow rate control means. The flow rate control means may be, for example, a flow meter for monitoring the flow rate of the raw material gas 33, or a valve for controlling the flow rate of the raw material gas 33.

[0016] As shown in Figures 1 and 2, the manufacturing apparatus 10 includes a film removal unit 14 for removing the passive film 21 of the catalyst 20. The film removal unit 14 may remove the passive film 21 by chemical methods such as reduction reactions, or by physical methods such as etching.

[0017] As shown in Figure 1, the film removal unit 14 may be, for example, a reducing gas supply unit 141 that supplies reducing gas 34 to the reactor 11 to reduce the passive film 21. It is preferable that the reducing gas supply unit 141 supplies the reducing gas 34 from the bottom of the reactor 11. The reducing gas 34, like the raw material gas 33, usually moves upward through the slurry 30 due to the difference in specific gravity with the slurry 30. Therefore, when the reducing gas 34 is supplied from the bottom of the reactor 11, it tends to ensure a sufficient distance for the reducing gas 34 to move within the slurry 30. As a result, the catalyst 20 and the reducing gas 34 tend to come into contact efficiently. Furthermore, from the viewpoint of avoiding the creation of dead spaces that are difficult for the reducing gas 34 to reach, it is preferable that the reducing gas supply unit 141 supplies the reducing gas 34 from the bottom of the reactor 11. When the reducing gas supply unit 141 supplies reducing gas 34 from the side of the slurry bed type reactor 11, it is preferable that the reducing gas supply unit 141 is connected at a position no more than 1 / 3 of the liquid level of the slurry 30.

[0018] As shown in Figure 2, the film removal unit 14 may be, for example, an external film removal unit 142 that removes the passive film 21 of the catalyst 20 outside the reactor 11. The external film removal unit 142 may remove the passive film 21 by chemical methods such as reduction reactions, or by physical methods such as etching. When removing the passive film 21 by reduction reactions, for example, the passive film 21 may be removed by supplying a reducing gas 34 into a heat-resistant and pressure-resistant external film removal unit 142 containing the catalyst 20 having the passive film 21. The catalyst 20 from which the passive film 21 has been removed by the external film removal unit 142 can be supplied to the reactor 11, for example, via a catalyst supply pipe 15 or by an operator.

[0019] As shown in Figures 1 and 2, the manufacturing apparatus 10 may include a liquid outlet pipe 16. The liquid outlet pipe 16 discharges the product liquid, which is generated in the slurry 30 over time as the FT reaction progresses, to the outside of the reactor 11. The liquid outlet pipe 16 is connected, for example, to the side of the reactor 11. When the liquid outlet pipe 16 is connected to the side of the reactor 11, the position where the liquid outlet pipe 16 is connected is usually designed to be lower than the liquid level of the slurry 30. The slurry 30 in the vicinity of the liquid outlet pipe 16 can be discharged to the outside of the reactor 11 along with the product liquid through the liquid outlet pipe 16.

[0020] The manufacturing apparatus 10 may include a liquid purification means connected to the liquid outlet pipe 16. The liquid purification means can separate the slurry 30 discharged through the liquid outlet pipe 16 from the generated liquid. The slurry 30 separated by the liquid purification means can be reused in the FT reaction as appropriate. The generated liquid separated by the liquid purification means can be recovered as the target product.

[0021] As shown in Figures 1 and 2, the manufacturing apparatus 10 may be equipped with a gas outlet pipe 17. The gas outlet pipe 17 discharges the product gas generated over time as the FT reaction progresses to the outside of the reactor 11. The gas outlet pipe 17 is connected, for example, to the top of the reactor 11. The raw material gas 33 supplied into the reactor 11 may rise through the slurry 30 and move to the gas phase portion 35 in the upper part of the reactor 11. The raw material gas 33 that has moved to the gas phase portion 35 can be discharged to the outside of the reactor 11 along with the product gas via the gas outlet pipe 17.

[0022] The manufacturing apparatus 10 may include a gas purification means connected to the gas outlet pipe 17. The gas purification means can separate the raw material gas 33 and the product gas discharged through the gas outlet pipe 17. The raw material gas 33 separated by the gas purification means can be reused in the FT reaction as appropriate. The product gas separated by the gas purification means can be recovered as the target product.

[0023] The manufacturing apparatus 10 may include a slurry introduction pipe for introducing slurry 30 into the reactor 11. The slurry introduction pipe is connected, for example, to the top, side, or bottom of the reactor 11. The manufacturing apparatus 10 may also include a slurry supply source connected to the slurry introduction pipe. Alternatively, the manufacturing apparatus 10 may include a catalyst source and an organic solvent source, and the slurry introduction pipe may be connected to the catalyst source and the organic solvent source, so that the catalyst 20 and the second organic solvent 32 (described later) are mixed inside the reactor 11 to prepare slurry 30.

[0024] The manufacturing apparatus 10 may include a slurry outlet pipe for discharging the slurry 30 to the outside of the reactor 11. The slurry outlet pipe may be connected, for example, to the side or bottom of the reactor 11.

[0025] The manufacturing apparatus 10 may be equipped with stirring means for stirring the slurry 30 and the raw material gas 33 in the reactor 11. When the slurry 30 and the raw material gas 33 are stirred by the stirring means in the reactor 11, the opportunity for contact between the slurry 30 and the raw material gas 33 increases, which can improve the reaction efficiency.

[0026] The manufacturing apparatus 10 may be equipped with heat exchange means for maintaining the temperature inside the reactor 11 within a predetermined range. Since the FT reaction is an exothermic reaction, the heat exchange means may be configured to suppress an excessive temperature rise inside the reactor 11. For example, the heat exchange means may include a heat exchange means body, a cooling medium introduction pipe for introducing a cooling medium into the heat exchange means body, and a heated steam outlet pipe for discharging heated steam from the heat exchange means body.

[0027] [Method for Producing Hydrocarbons] The method for producing hydrocarbons according to this embodiment includes a film removal step and a production step. In the film removal step, the passivation film 21 of the catalyst 20 having a passivation film 21 is removed. In the production step, in the presence of the catalyst 20 from which the passivation film 21 was removed in the film removal step, a raw material gas 33 containing hydrogen gas and carbon monoxide gas is reacted by a Fischer-Tropsch reaction (FT reaction) to produce hydrocarbons.

[0028] The passivation film 21 is formed to prevent the catalyst 20 from being oxidized and deactivated by exposure to the atmosphere before use. However, a catalyst 20 with a passivation film 21 has low activity and cannot perform adequately if used as is. In contrast, in this embodiment, the passivation film 21 on the catalyst 20 is removed in a film removal step before the production step. As a result, in this embodiment, the production step starts with the catalyst 20 in a highly active state, making it easier for the catalyst 20 to perform well and increasing the carbon monoxide conversion rate. Furthermore, this embodiment also has the effect of producing long-chain hydrocarbons with high selectivity because the catalyst 20's performance is more easily exhibited. Moreover, this embodiment may also have the effect of allowing the FT reaction to proceed in a shorter time because the catalyst 20's performance is more easily exhibited.

[0029] The hydrocarbon production method of this embodiment can be carried out using the production apparatus 10 described above. The film removal step and the production step may be carried out using the same equipment or using different equipment. From the viewpoint of simplifying the production apparatus 10, it is preferable that the film removal step and the production step be carried out using the same equipment. In this case, for example, the film removal step and the production step are carried out using the reactor 11 described above. On the other hand, there may be situations where it is desirable to carry out the production step and the film removal step simultaneously, such as when it is desired to add the catalyst 20 from which the passive film 21 has been removed during the production step. From the viewpoint of easily accommodating such situations, it is preferable that the film removal step and the production step be carried out using different equipment. In this case, for example, the film removal step may be carried out using the external film removal unit 142 described above, and the production step may be carried out using the reactor 11 described above.

[0030] The catalyst 20 may include, for example, a catalyst metal and a carrier supporting the catalyst metal. Before the film removal step, a passivation film 21 is formed on the surface of the catalyst metal. The passivation film 21 is, for example, an oxide film formed by oxidation of the surface of the catalyst metal. The thickness of the passivation film 21 is not particularly limited, but is, for example, about 0.15 to 10 nm. The passivation film 21 is formed, for example, by passivation treatment to prevent the catalyst 20 from being exposed to the atmosphere and oxidizing and becoming inactive between the time of manufacture and use of the catalyst 20.

[0031] The catalyst metal may contain at least one selected from the group consisting of cobalt, nickel, ruthenium, and iron. From the viewpoint of obtaining middle distillates such as diesel fuel, jet fuel, and kerosene, it is preferable that the catalyst metal contains cobalt.

[0032] The support is silica (SiO ２ ), Zirconia (ZrO ２ ), magnesia (MgO), cerium oxide (CeO ２ ), Titania (TiO ２ ), alumina (Al ２ O ３ The support may include at least one selected from the group consisting of ) and zeolite (aluminosilicate). From the viewpoint of exhibiting performance derived from the catalyst metal and contact efficiency with the raw material gas, the support preferably contains silica.

[0033] The catalyst 20 may further contain at least one rare earth element selected from the group consisting of yttrium, cerium, lanthanum, praseodymium, neodymium, and holmium; at least one alkali metal selected from the group consisting of sodium, potassium, rubidium, and cesium; at least one alkaline earth metal selected from the group consisting of beryllium, magnesium, calcium, strontium, and barium; and copper, etc.

[0034] The loading amount, which is the mass ratio of the catalyst metal to the total amount of catalyst 20, may be adjusted as appropriate. The loading amount is preferably 5% by mass or more, and more preferably 10% by mass or more. This tends to improve the carbon monoxide conversion rate. Alternatively, the loading amount is preferably 30% by mass or less, and more preferably 25% by mass or less. This tends to improve the chain growth rate.

[0035] The shape of the catalyst 20 is not particularly limited, and may be, for example, in powder form. The particle size of the catalyst 20 is not particularly limited, and may be, for example, 1 μm or more and 1000 μm or less as measured by laser diffraction. If the particle size of the catalyst 20 is 1 μm or more, the catalyst 20 will be less likely to flow out of the reactor 11. If the particle size of the catalyst 20 is 1000 μm or less, the specific surface area of ​​the catalyst 20 will increase, which tends to improve the reaction efficiency.

[0036] The film removal process may be carried out by chemical methods such as reduction reactions, or by physical methods such as etching. From the viewpoint of efficiently removing the passive film 21, it is preferable that the film removal process be carried out by a reduction reaction.

[0037] When removing the passive film 21 by a reduction reaction, for example, the passive film 21 can be removed by supplying a reducing gas to the catalyst 20 and bringing it into contact with it. In this case, the passive film 21 may also be removed by supplying a reducing gas 34 to a slurry 30 containing the catalyst 20 and the first organic solvent 31, thereby bringing the reducing gas 34 into contact with the catalyst 20. From the viewpoint of facilitating the continuous performance of the film removal step and the production step, it is preferable that the first organic solvent 31 is the same as the second organic solvent 32 used in the production step. The reducing gas 34 is not particularly limited as long as it can reduce the passive film 21, and may include, for example, hydrogen gas, a mixture of hydrogen gas and water vapor, carbon monoxide gas, etc. From the viewpoint of high reducing power, it is preferable that the reducing gas 34 includes hydrogen gas.

[0038] Note that in the present embodiment, an operation of supplying both hydrogen gas and carbon monoxide gas to the catalyst 20 at the same time, such as the supply of the raw material gas 33, is not included in the film removal step. When both hydrogen gas and carbon monoxide gas are supplied to the catalyst at the same time, a reduction reaction of the passivation film 21 possessed by the catalyst 20 may also occur, but a hydrocarbon generation reaction occurs in competition. Therefore, in the operation of supplying both hydrogen gas and carbon monoxide gas to the catalyst 20 at the same time, the passivation film 21 cannot be effectively removed, and in the subsequent generation step, the conversion rate of carbon monoxide and the selectivity for long-chain hydrocarbons are unlikely to increase. Therefore, in the present embodiment, the operation of supplying both hydrogen gas and carbon monoxide gas to the catalyst 20 at the same time, such as the supply of the raw material gas 33, is not included in the film removal step, and the film removal step is provided separately from the generation step.

[0039] The reduction temperature when removing the passivation film 21 by supplying the reducing gas 34 to the slurry 30 containing the catalyst 20 and the first organic solvent 31 is not particularly limited, and is, for example, 200°C or higher and 500°C or lower. The time for supplying the reducing gas 34 is preferably 10 minutes or longer, more preferably 30 minutes or longer, and even more preferably 60 minutes or longer. This makes it easy to sufficiently remove the passivation film 21. In addition, the time for supplying the reducing gas 34 is preferably 480 minutes or shorter, more preferably 360 minutes or shorter, and even more preferably 240 minutes or shorter. As a result, the time required for the film removal step and the usage amount of the reducing gas 34 do not become excessive, and the passivation film 21 can be efficiently removed.

[0040] In the generation step, as described above, in the presence of the catalyst 20 from which the passivation film 21 has been removed in the film removal step, the raw material gas 33 containing hydrogen gas and carbon monoxide gas is reacted through a Fischer-Tropsch reaction (FT reaction) to generate hydrocarbons.

[0041] The raw material gas 33 contains at least hydrogen gas and carbon monoxide gas. The raw material gas 33 may further contain carbon dioxide gas. From the viewpoint that the rate of the FT reaction depends on the hydrogen partial pressure, the partial pressure ratio (molar ratio) of hydrogen to the total of carbon monoxide and carbon dioxide in the raw material gas 33 may be 0.6 or more and 2.7 or less, may be 0.8 or more and 2.5 or less, and may be 1.0 or more and 2.3 or less. The ratio of carbon monoxide to carbon dioxide in the raw material gas 33 can also be adjusted as appropriate. For example, from the viewpoint of carbon recycling, it is preferable to increase the ratio of carbon dioxide, and from the viewpoint of increasing the conversion rate to hydrocarbons, it is preferable to increase the ratio of carbon monoxide. The ratio of carbon dioxide may be 1 vol% or more, 10 vol% or more, 30 vol% or more, or 40 vol% or more relative to the total amount of carbon monoxide and carbon dioxide.

[0042] The raw material gas 33 may contain other components such as sulfur content, organic nitrogen content, phosphorus content and the like. The content of these other components is preferably 20 vol% or less relative to the entire raw material gas 33.

[0043] The production of hydrocarbons in the production step may be a slurry bed system, or may be other systems such as a fixed bed system, a fluidized bed system and the like. Among these, in the production step, it is preferable to produce hydrocarbons by a slurry bed system. The slurry bed type FT reaction tends to be superior in temperature controllability as compared with a fixed bed type FT reaction and the like. The slurry 30 used in the slurry bed type production step contains an organic solvent, and in the present embodiment, the organic solvent contained in the slurry 30 used in the slurry bed type production step is referred to as "second organic solvent 32".

[0044] The second organic solvent 32 serves as a medium for suspending the catalyst 20 for a gas-liquid system contact reaction. The second organic solvent 32 is not particularly limited, but is preferably a liquid hydrocarbon. This reduces the need to separately purify the produced liquid and the second organic solvent, and facilitates recovery of the produced liquid. The liquid hydrocarbon is, for example, a saturated hydrocarbon having 5 to 20 carbon atoms.

[0045] If the boiling point of the second organic solvent 32 is too low, a large amount of the second organic solvent will volatilize during the FT reaction; therefore, it is preferable that the boiling point of the second organic solvent 32 be 200°C or higher. Examples of the second organic solvent 32 that has a boiling point of 200°C or higher and is a liquid hydrocarbon include saturated hydrocarbons having 12 to 20 carbon atoms. Among these, it is preferable that the second organic solvent 32 contains one or more selected from the group consisting of pentadecane (15 carbon atoms), hexadecane (16 carbon atoms), heptadecane (17 carbon atoms), and octadecane (18 carbon atoms).

[0046] The concentration of catalyst 20 in slurry 30 is expressed as the ratio [%] of the mass [g] of catalyst 20 to the volume [mL] of slurry 30, and can be adjusted as appropriate. The above ratio is preferably 2.5% or more and 40% or less. When the above ratio is 2.5% or more, the carbon monoxide conversion rate and the selectivity of long-chain hydrocarbons tend to improve. When the above ratio is 40% or less, it tends to prevent the catalyst 20 from precipitating excessively in slurry 30.

[0047] The temperature inside the equipment during the production process is, for example, between 100°C and 300°C. The pressure (gauge pressure) inside the equipment during the production process is, for example, between 0.1 MPaG and 3.0 MPaG.

[0048] The flow rate of the raw material gas 33 in the production process is preferably 1 L / min or more, more preferably 3 L / min or more, and even more preferably 5 L / min or more. This tends to ensure a sufficient supply of raw material gas 33. Alternatively, the flow rate of the raw material gas 33 in the production process is preferably 20 L / min or less, more preferably 15 L / min or less, and even more preferably 12 L / min or less. This tends to reduce pressure loss.

[0049] In the production process, the raw material gas 33 comes into contact with the catalyst 20, and the FT reaction proceeds, generating hydrocarbons. The generated hydrocarbons may include a liquid product and / or a gas product. The liquid product is a hydrocarbon with a relatively high boiling point and a high carbon number, such as heavy naphtha fraction (crude gasoline), kerosene, and diesel fuel. The gas product is a hydrocarbon with a relatively low boiling point and a low carbon number, such as hydrocarbons with 1 to 4 carbon atoms. Specific examples of gas products include methane, ethane, ethylene, propane, propylene, butane, and butene.

[0050] (Embodiment 1) Hereinafter, Embodiment 1, which is an example of a specific embodiment of the method for producing hydrocarbons, will be described with reference to Figures 3 to 6. First, a first organic solvent 31 and a catalyst 20 having a passivation film 21 are put into a reactor 11 (Figure 3). Next, as a film removal step, a reducing gas 34 is supplied to the reactor 11 (Figure 4). This removes the passivation film 21 of the catalyst 20 (Figure 5). Next, as a production step, a raw material gas containing hydrogen gas and carbon monoxide gas is supplied to the reactor 11 (Figure 6). This produces hydrocarbons by an FT reaction in the presence of the catalyst 20 from which the passivation film 21 has been removed. In Embodiment 1, the first organic solvent 31 used in the film removal step can be used as is as the second organic solvent 32 in the production step.

[0051] (Embodiment 2) Next, Embodiment 2, which is an example of a specific embodiment of the hydrocarbon production method, will be described using Figures 7 to 11. First, a catalyst 20 having a passivation film 21 is introduced into a reactor 11 (Figure 7). Next, as a film removal step, a reducing gas 34 is supplied to the reactor 11 (Figure 8). This removes the passivation film 21 from the catalyst 20 (Figure 9). Next, a second organic solvent 32 is introduced into the reactor 11 containing the catalyst 20 from which the passivation film 21 has been removed (Figure 10). Next, as a production step, a raw material gas containing hydrogen gas and carbon monoxide gas is supplied to the reactor 11 (Figure 11). This generates hydrocarbons by the FT reaction in the presence of the catalyst 20 from which the passivation film 21 has been removed.

[0052] [Hydrogen Production System] The hydrocarbon production apparatus 10 described above can be combined with other apparatus to form a hydrocarbon production system 50. Figure 12 shows an example of a hydrocarbon production system 50. As shown in Figure 12, the hydrocarbon production system 50 includes, for example, a raw material gas generator 40 and a hydrocarbon production apparatus 10. The raw material gas generator 40 is an apparatus that generates the raw material gas 33 used in the production apparatus 10.

[0053] As shown in Figure 12, the raw material gas generator 40 may include, for example, a combustion device 41 and a reverse shift reactor 42 that generates raw material gas 33 from the mixed gas discharged from the combustion device 41. The combustion device 41 may be any known type, such as a CFB (Circulating Fluidized Bed) boiler, a BFB (Bubbling Fluidized Bed) boiler, or a rotary kiln. As shown in Figure 12, the combustion device 41 discharges, for example, a mixed gas containing hydrogen gas and carbon dioxide gas. As shown in Figure 12, the reverse shift reactor 42 generates, for example, a mixed gas containing hydrogen gas, carbon monoxide gas, and carbon dioxide gas from the mixed gas discharged from the combustion device 41 by a reverse shift reaction. The mixed gas produced by the reverse shift reactor 42 is supplied to the reactor 11 as the raw material gas 33, for example, via the raw material gas supply unit 12 of the manufacturing apparatus 10.

[0054] The embodiments will be described in more detail below based on examples. These embodiments are not limited to these examples.

[0055] [Example 1] (Catalyst) A catalyst was prepared in which cobalt was supported as a catalytic metal on silica, which was used as a support. The amount of catalytic metal supported in this catalyst was 10% by mass of the total catalyst. The true specific gravity of the catalyst, as determined by the Gay-Lussac gravity bottle method, was 2.25 g / cm³. ３ Furthermore, this catalyst had undergone passivation treatment, resulting in a passivation film formed on the surface of the catalyst metal by the oxidation of cobalt.

[0056] (Film Removal Process) 15 g of the catalyst was placed in a reactor having the same configuration as the reactor shown in Figure 1, but with an inner diameter of 50 mm. Hydrogen gas was supplied as a reducing gas to remove the passive film by reduction. The reduction temperature at this time was 230°C. The supply time of the reducing gas was 120 minutes.

[0057] (Production Process) Next, hexadecane was supplied as the second organic solvent to the reactor used in the film removal process so that the liquid level reached 70-80 mm. Then, the supply of raw material gas containing hydrogen gas, carbon monoxide gas, and carbon dioxide gas was started. This initiated the production of hydrocarbons by the FT reaction in a slurry bed. In the raw material gas, the mole fraction of hydrogen gas was 53%, the mole fraction of carbon monoxide gas was 27%, and the mole fraction of carbon dioxide gas was 20%. The temperature inside the reactor during the production process was 230°C, and the pressure (gauge pressure) inside the reactor was 0.6 MPaG. The reaction time was 10 hours, during which the product liquid was withdrawn from the liquid outlet pipe and the product gas was withdrawn from the gas outlet pipe.

[0058] [Example 2] Example 2 was carried out in the same manner as Example 1, except that the reduction temperature was changed to 450°C.

[0059] [Example 3] In the film removal step, before adding the catalyst to the reactor, hexadecane was supplied as the first organic solvent to a liquid level of 70-80 mm, and otherwise, Example 3 was carried out in the same manner as in Example 1. That is, in Example 3, in the film removal step, the passive film was removed by supplying a reducing gas to the slurry containing the catalyst and the first organic solvent. Furthermore, the first organic solvent (hexadecane) used in the film removal step was used as the second organic solvent in the production step.

[0060] [Example 4] Example 4 was carried out in the same manner as in Example 3, except that the first and second organic solvents were replaced with octadecane.

[0061] [Comparative Example 1] The procedure of Comparative Example 1 was carried out in the same manner as in Example 1 except that the film removal step was not performed. That is, in Comparative Example 1, 15 g of the above catalyst was placed in a reactor, hexadecane was further supplied as the second organic solvent so that the liquid surface height was 70 to 80 mm, and a raw material gas was supplied thereto to start the production of hydrocarbons.

[0062] [Measurement of Carbon Monoxide Conversion Rate (CO Conversion Rate)] In Examples 1 to 4 and Comparative Example 1, after the completion of the reaction, the CO conversion rate was measured as follows. H ２ , CO and CH ４ were analyzed using a thermal conductivity detector gas chromatograph TCD-GC (GC323, manufactured by GL Sciences Inc.). For the analysis of hydrocarbons having 1 to 6 carbon atoms, a gas chromatograph equipped with a flame ionization detector was used. Argon was used as the carrier gas. For hydrocarbons with 6 or more carbon atoms, the supernatant of the stationary slurry liquid was collected for analysis. A device equipped with a separation column was used for measuring the product oil distribution. The CO conversion rate was calculated from the above analysis results using the following formula. For details, reference can be made to Journal of Synthetic Organic Chemistry, Japan, Vol. 41, No. 6, 1983, p. 532-544.

[0063] CO conversion rate [%] = (A - B) / A × 100 A: Number of moles of carbon monoxide in the raw material gas per unit time B: Number of moles of carbon monoxide in the outlet gas per unit time

[0064] That is, the carbon monoxide conversion rate (CO conversion rate) was calculated based on the raw material gas flow rate, the flow rates of the produced gas and produced liquid, and the results of analysis by gas chromatography. The results are shown in Table 1.

[0065] [Measurement of 1-butene / butane ratio (C4' / C4 ratio)] In Examples 1 to 4 and Comparative Example 1, after the completion of the reaction, a part of the produced gas extracted from the gas outlet pipe was sampled and subjected to GC analysis under the following conditions without undergoing treatments such as heat retention.

[0066] GC analysis conditions: A separation column, consisting of a stainless steel tube with an outer diameter of 4 mm, an inner diameter of 3 mm, and a length of 2 m, packed with porous spherical silica (Unipack-S, 100-150 mesh, manufactured by GL Sciences), was mounted on a gas chromatograph (Shimadzu GC14-B) equipped with a flame ionization detector (FID). Argon was used as the carrier gas (mobile phase), and the mobile phase flow rate was 30 mL / min at standard conditions. The initial column temperature was 50°C. A 1.0 mL gas sample was injected from a gas sampler, and simultaneously, the temperature was increased at 4°C / min until it reached 130°C, where it was maintained for component analysis. The time required for the analysis of 1-butene and butane was 15 minutes. A chromatogram was generated using a self-recording integrator (Shimadzu C-R8A), and numerical data was simultaneously recorded in memory. The carrier gas flow rate was measured using a soap film flow meter. The time required to reset the column temperature after the analysis was approximately 5 minutes.

[0067] Based on the results of the GC analysis described above, the content of 1-butene and butane in the generated gas was determined, and the 1-butene / butane ratio (C4' / C4 ratio) in the generated gas was calculated. The results are shown in Table 1.

[0068]

[0069] The results shown in Table 1 show that the hydrocarbon production method of this embodiment, by including a film removal step before the production step, increases the carbon monoxide conversion rate. Furthermore, the hydrocarbon production method of this embodiment, by including a film removal step before the production step, also increases the 1-butene / butane ratio in the produced gas. While butane is a saturated hydrocarbon, 1-butene is an unsaturated hydrocarbon, making it easier to produce long-chain hydrocarbons through chain reactions. Therefore, the larger the 1-butene / butane ratio, the easier it is to obtain long-chain hydrocarbons suitable for SAF. In other words, the results shown in Table 1 show that the hydrocarbon production method of this embodiment, by including a film removal step before the production step, can produce long-chain hydrocarbons suitable for SAF with high selectivity.

[0070] 10...Hydrogen production apparatus, 11...Reactor, 12...Raw material gas supply unit, 13...Raw material gas supply pipe, 14...Film removal unit, 141...Reducing gas supply unit, 142...External film removal unit, 15...Catalyst supply pipe, 16...Liquid outlet pipe, 17...Gas outlet pipe, 20...Catalyst, 21...Passivation film, 30...Slurry, 31...First organic solvent, 32...Second organic solvent, 33...Raw material gas, 34...Reducing gas, 35...Gas phase section, 40...Raw material gas generator, 41...Combustion unit, 42...Reverse shift reactor, 50...Hydrogen production system

Claims

1. A method for producing hydrocarbons, comprising: a film removal step of removing a passive film from a catalyst; and a production step of reacting a raw material gas containing hydrogen gas and carbon monoxide gas by a Fischer-Tropsch reaction in the presence of the catalyst from which the passive film has been removed in the film removal step to produce hydrocarbons.

2. The method for producing hydrocarbons according to claim 1, wherein in the film removal step, the passive film is removed by a reduction reaction.

3. The method for producing hydrocarbons according to claim 2, wherein in the film removal step, the passive film is removed by supplying a reducing gas to a slurry containing the catalyst and the first organic solvent.

4. The method for producing hydrocarbons according to claim 3, wherein the reducing gas includes hydrogen gas.

5. The method for producing hydrocarbons according to claim 1, wherein in the production step, hydrocarbons are produced by a slurry bed method using a second organic solvent.

6. The method for producing a hydrocarbon according to claim 5, wherein the second organic solvent is a liquid hydrocarbon.

7. The method for producing hydrocarbons according to claim 5, wherein the boiling point of the second organic solvent is 200°C or higher.

8. The method for producing hydrocarbons according to claim 1, wherein the film removal step and the production step are performed using the same equipment.

9. The method for producing hydrocarbons according to claim 1, wherein the catalyst comprises at least one catalytic metal selected from the group consisting of cobalt, nickel, ruthenium, and iron.

10. The method for producing hydrocarbons according to claim 9, wherein the catalyst comprises the catalytic metal and a carrier supporting the catalytic metal.

11. The method for producing hydrocarbons according to claim 10, wherein the carrier contains silica.

12. The method for producing hydrocarbons according to claim 11, wherein the catalyst metal includes cobalt.

13. A hydrocarbon production apparatus comprising: a film removal unit for removing a passive film from a catalyst; a reactor for producing hydrocarbons by reacting a raw material gas containing hydrogen gas and carbon monoxide gas in the presence of the catalyst from which the passive film has been removed by the film removal unit via a Fischer-Tropsch reaction; and a raw material gas supply unit for supplying the raw material gas to the reactor.

14. The hydrocarbon production apparatus according to claim 13, wherein the film removal unit is a reducing gas supply unit that supplies a reducing gas for reducing the passivation film to the reactor.

15. A hydrocarbon production system comprising: a hydrocarbon production apparatus according to claim 13; and a raw material gas production apparatus for producing the raw material gas.

16. The hydrocarbon production system according to claim 15, wherein the raw material gas generating apparatus comprises a combustion apparatus and a reverse shift reactor that generates the raw material gas from a mixed gas discharged from the combustion apparatus.

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