Apparatus and method for producing synthetic fuel

Abstract

The present invention provides an apparatus and a method for producing a synthetic fuel, by which a hydrocarbon having a high selectivity of a jet fuel component can be obtained and a jet fuel can be produced with a high yield. Disclosed is an apparatus 1 for producing a synthetic fuel, the apparatus being used for the production of a specific synthetic fuel by means of a direct FT synthesis reaction using a starting material gas that contains hydrogen and carbon dioxide. This apparatus 1 for producing a synthetic fuel comprises: a reactor 9 which has a cylindrical reactor main body part 9a that is filled with a predetermined FT catalyst 20 for causing a direct FT synthesis reaction in the reactor main body part 9a; a starting material gas flow rate adjustment part 7 and / or composition adjustment parts 5a, 5b for adjusting the flow rate of the starting material gas to be supplied to the reactor 9; and a control device 3 for controlling the linear velocity, which is the flow rate of the starting material gas per the cross-sectional area of the reactor main body part 9a by controlling the starting material gas flow rate adjustment part 7 and / or the composition adjustment parts 5a, 5b. The control device 3 controls the linear velocity to 0.2-4.0 m / sec in cases where the predetermined synthetic fuel is a jet fuel.

Description

Synthetic fuel production device and production method

[0001] The present invention relates to an apparatus and method for producing a synthetic fuel, particularly jet fuel, by a direct FT synthesis reaction using a feed gas containing hydrogen and carbon dioxide.

[0002] Conventionally, a method for producing jet fuel using the Fischer-Tropsch (FT) synthesis reaction from synthesis gas containing hydrogen and carbon monoxide is known, for example, as disclosed in Patent Document 1. In this jet fuel production method, a chemical reaction is used to synthesize alkanes from synthesis gas in a reactor packed with an FT catalyst for causing the FT synthesis reaction, and FT crude oil containing a variety of hydrocarbons is produced. Then, this FT crude oil is subjected to a combination of multiple processes, including hydrotreatment, alkylation, and aromatization, thereby achieving a high yield of synthetic fuel suitable for jet fuel.

[0003] Furthermore, in recent years, research has been conducted into direct FT synthesis, in which FT synthesis is performed using carbon dioxide instead of carbon monoxide in synthesis gas, with the aim of achieving carbon neutrality. Patent Application No. 2022-052774, already filed by the present applicant, proposes an FT catalyst for producing hydrocarbons with a carbon number of 5 or more at a high yield using a mixed gas of hydrogen and carbon dioxide as the feedstock gas. This FT catalyst contains Fe (iron) and Zr (zirconium) as catalytic metals, and may also contain Ga (gallium) and Na (sodium).

[0004] Patent No. 5826488

[0005] However, the above-mentioned FT catalysts do not provide sufficient selectivity for synthetic fuels suitable for jet fuel, specifically synthetic fuels containing hydrocarbons with carbon numbers of 8 to 16. The present inventors conducted extensive research and found that the selectivity for hydrocarbons having a desired carbon number can be increased based on the relationship between the FT catalyst packed into a reactor and the flow rate and velocity of the feed gas supplied to the reactor, thereby completing the present invention.

[0006] The present invention has been made to solve the above-mentioned problems, and has an object to provide a synthetic fuel production apparatus and production method that can obtain a predetermined synthetic fuel, in particular hydrocarbons with a high selectivity for jet fuel components, and can produce jet fuel with a high yield.

[0007] In order to achieve the above object, the invention of claim 1 provides a synthetic fuel production apparatus (synthetic fuel production apparatus 1 in this embodiment (hereinafter the same in this paragraph)) for producing a predetermined synthetic fuel by a direct FT synthesis reaction using a feedstock gas containing hydrogen and carbon dioxide, the apparatus comprising: a reactor 9 having a cylindrical reactor main body 9a and filled with a predetermined FT catalyst 20 for causing a direct FT synthesis reaction in the reactor main body; an adjusting unit (feedstock gas flow rate adjusting unit 7 and / or composition adjusting units 5a, 5b) for adjusting the flow rate of the feedstock gas supplied to the reactor; and control means (control device 3) for controlling the linear velocity, which is the flow rate of the feedstock gas per cross-sectional area of ​​the reactor main body, by controlling this adjusting unit, wherein the control means controls the linear velocity to 0.2 to 4.0 m / sec when the predetermined synthetic fuel is jet fuel.

[0008] According to this configuration, the reactor has a cylindrical reactor main body, and this reactor main body is filled with a predetermined FT catalyst for causing a direct FT synthesis reaction. Furthermore, a control means controls an adjustment unit for adjusting the flow rate of the feed gas supplied to the reactor. When the predetermined synthetic fuel to be produced is jet fuel, the linear velocity, which is the flow rate of the feed gas per cross-sectional area of ​​the reactor main body, is controlled to 0.2 to 4.0 m / sec. By supplying the feed gas to the reactor at a linear velocity within the above range, it is possible to obtain the predetermined synthetic fuel, particularly hydrocarbons with high selectivity for jet fuel components, and to produce jet fuel with a high yield.

[0009] A second aspect of the present invention is the synthetic fuel production apparatus according to the first aspect, characterized in that the control means controls the linear velocity to 2.7 to 3.0 m / sec.

[0010] According to this configuration, by controlling the linear velocity to 2.7 to 3.0 m / sec by the control means, it is possible to obtain hydrocarbons as jet fuel components with a higher selectivity.

[0011] The invention of claim 3 is a synthetic fuel manufacturing method for producing a predetermined synthetic fuel by a direct FT synthesis reaction using a feedstock gas containing hydrogen and carbon dioxide, and is characterized by comprising: a reactor preparation step of preparing a reactor 9 in which a cylindrical reactor main body 9a is filled with an FT catalyst for causing a direct FT synthesis reaction; and a feedstock gas supply step of supplying the feedstock gas to the reactor so that the linear velocity, which is the flow rate of the feedstock gas per cross-sectional area of ​​the reactor main body, is 0.2 to 4.0 m / sec when the predetermined synthetic fuel is jet fuel.

[0012] According to this configuration, when a predetermined synthetic fuel is produced by a direct FT synthesis reaction using a feed gas containing hydrogen and carbon dioxide, first, a reactor is prepared in which a predetermined FT catalyst is packed into the cylindrical reactor main body (reactor preparation step). Next, when the predetermined synthetic fuel to be produced is jet fuel, the feed gas is supplied to the reactor so that the linear velocity, which is the flow rate of the feed gas per cross-sectional area of ​​the reactor main body, is 0.2 to 4.0 m / sec (feed gas supply step). By supplying the feed gas to the reactor at a linear velocity within the above range, it is possible to produce the predetermined synthetic fuel, particularly a synthetic fuel containing hydrocarbons with a high selectivity for jet fuel components.

[0013] 1 is a diagram schematically illustrating a synthetic fuel production apparatus to which a synthetic fuel production apparatus and production method according to one embodiment of the present invention is applied. (a) is a diagram illustrating a reactor packed with an FT catalyst, and (b) is a diagram illustrating the linear velocity of a feed gas supplied to the reactor. (b) is a graph illustrating the distillation properties of a synthetic fuel obtained when a feed gas is supplied to a reactor at a high linear velocity and a low linear velocity. (c) is a graph illustrating a hydrocarbon distribution showing the relationship between the carbon number and weight of hydrocarbons contained in a synthetic fuel, where (a) shows a Jet-A1 standard jet fuel, (b) shows a synthetic fuel obtained at a low linear velocity, and (c) shows a hydrocarbon distribution of a synthetic fuel obtained at a high linear velocity. (d) is a graph illustrating the relationship between feed gas linear velocity and Jet fuel selectivity based on test results. (e) is a graph illustrating the pore distribution showing the relationship between pore diameter and pore volume for two types of FT catalysts.

[0014] Preferred embodiments of the present invention will be described in detail below with reference to the drawings. Figure 1 schematically shows a synthetic fuel production apparatus to which a synthetic fuel production apparatus and production method according to one embodiment of the present invention is applied. As shown in the figure, this synthetic fuel production apparatus 1 includes a raw material gas supply section, a composition adjustment section, a compression section, a flow rate adjustment section, a preheating section, a catalytic reaction section, a cooling section, a gas-liquid separation section, and a collection section, which are connected via piping 2 and controlled by a control device 3 (control means).

[0015] The raw material gas supply unit is H ２ Supply unit 4a and CO ２ supplying parts 4a and 4b, which respectively supply hydrogen and carbon dioxide. ２ Supply unit 4a and CO ２ On the downstream side of the supply section 4b, ２ Composition adjustment section 5a and CO ２ By controlling these, H 2 supplied as a raw material gas to a reactor 9 of the catalytic reaction section (described later) is adjusted. ２ and CO ２ The composition and mixing ratio of the mixed gas are adjusted. ２ Composition adjustment section 5a and CO ２The composition adjusting section 5b is controlled by the control device 3, and is therefore capable of adjusting the flow rate of the raw material gas either alone or in cooperation with a raw material gas flow rate adjusting section 7, which will be described later.

[0016] The compression unit has a compressor 6 and is controlled by the control device 3 to pressurize the raw material gas to a predetermined pressure (e.g., 3 MPa). The flow rate adjustment unit has a raw material gas flow rate adjustment unit 7 and is controlled by the control device 3 to adjust the flow rate of the raw material gas compressed by the compressor 6.

[0017] The preheating section has a preheating tube 8a and a preheater 8b, and the preheater 8b is controlled by the control device 3, thereby heating the raw material gas passing through the preheating tube 8a connected to the piping 2 to a predetermined temperature.

[0018] The catalytic reaction section has a reactor 9 and a temperature adjustment section 10. As shown in Fig. 2(a) , the reactor 9 has a cylindrical reactor main body 9a having a predetermined inner diameter, and this reactor main body 9a is filled with the FT catalyst 20. Note that the preparation of the reactor 9, which involves filling the reactor main body 9a with the FT catalyst 20, corresponds to the reactor preparation step in the method for producing synthetic fuel of the present invention, and this reactor preparation step may include a step of heating the inside of the reactor 9 to a predetermined temperature (such as a reaction temperature) using an inert gas or the like.

[0019] The FT catalyst 20 is intended to generate a plurality of types of hydrocarbons with different carbon numbers by causing a direct FT synthesis reaction in the raw material gas supplied to the reactor 9. The FT catalyst 20 is similar to the FT catalyst disclosed in Japanese Patent Application No. 2022-052774 already filed by the present applicant, and specifically, is configured to contain Fe, Zr, Ga, and Na as metal catalysts. The FT catalyst 20 is also made up of a large number of pellets, each having a predetermined size and shape, and each of which is configured to have a large number of pores. These pores have a specific surface area of ​​approximately 30 m ２ / g, and the average pore diameter is 10 to 100 nm.

[0020] Furthermore, the temperature adjusting section 10 in the catalytic reaction section is controlled by the control device 3, and the temperature of the direct FT synthesis reaction occurring in the reactor 9 is adjusted to a predetermined temperature (for example, 380°C).

[0021] As shown by the two-dot chain line in FIG. 1 , in the synthetic fuel production apparatus 1, the raw material gas is maintained at high pressure from the compression section to the catalytic reaction section described above, and as shown by the one-dot chain line in FIG. 1 , the raw material gas is heated from the preheating section to the catalytic reaction section.

[0022] The cooling section has a cooler 11, and the cooler 11 is controlled by the control device 3 to cool the product discharged from the reactor 9.

[0023] The gas-liquid separation section has a gas-liquid separator 12, which separates the product liquefied by cooling in the cooler 11 from the gaseous post-reaction gas that remains without reacting or liquefying. Although the post-reaction gas is discharged to the outside of the synthetic fuel production apparatus 1, it is effectively reused as a raw material gas for other refining processes or chemical reactions.

[0024] The collection section has a collection tank 13, and the liquid product separated by the gas-liquid separator 12 is collected by this collection tank 13.

[0025] In the synthetic fuel production apparatus 1 configured as described above, as will be described below, by causing the direct FT synthesis reaction while controlling the linear velocity of the feedstock gas supplied to the reactor 9 within a predetermined range, it is possible to obtain synthetic fuel containing hydrocarbons with a high selectivity for jet fuel components, and to produce jet fuel with a high yield.

[0026] The linear velocity is the flow rate of the raw material gas per unit cross-sectional area of ​​the inside of the cylindrical reactor main body 9a of the reactor 9, as shown in FIG. 2(b), and is defined by the following formula: Linear velocity (m / sec) = Raw material gas flow rate (m ３ / sec) / cross-sectional area (m ２ )

[0027] 3 shows the results of a distillation test of the synthetic fuel obtained by using the synthetic fuel production apparatus 1 to supply a feed gas to the reactor 9 at a relatively low linear velocity (0.123 m / sec) and a relatively high linear velocity (2.88 m / sec) and then causing a direct FT synthesis reaction under predetermined conditions (reactor temperature: 380°C, reactor pressure: 3 MPa). The horizontal axis shows the distillate amount (wt%), and the vertical axis shows the distillate temperature (°C). The distillate temperatures TH and TL in the figure represent the upper and lower limit distillation temperatures suitable for jet fuel components, respectively. Specifically, the upper limit distillation temperature TH is 232°C, and the lower limit distillation temperature TL is 157°C.

[0028] As shown by the two-dot chain line in FIG. 3, the selectivity of jet fuel was 20% in the synthetic fuel obtained by supplying the raw material gas to the reactor 9 at a low linear velocity.

[0029] In contrast, as shown by the solid line in Figure 3, the jet fuel selectivity of the synthetic fuel obtained by supplying the raw material gas to the reactor 9 at a high linear velocity was significantly higher than that at a low linear velocity, reaching 55%.

[0030] 4 shows the hydrocarbon distribution representing the relationship between the carbon number and weight of the hydrocarbons contained in the synthetic fuels obtained at the low and high linear velocities described above, with the solid line representing straight-chain hydrocarbons and the dashed line representing aromatic hydrocarbons. For reference, FIG. 4(a) shows the hydrocarbon distribution of a jet fuel of a specified standard (Jet-A1).

[0031] As shown in FIG. 4( a), the distribution of linear and aromatic hydrocarbons in Jet-A1 jet fuel includes hydrocarbons with carbon numbers of 7 to 20, and in particular, hydrocarbons with carbon numbers of 8 to 16, which is a range suitable for jet fuel (hereinafter referred to as the "Jet range"), making up the majority of the hydrocarbons.

[0032] In contrast, as shown in Figure 4(b), the synthetic fuel obtained at a low linear velocity contains hydrocarbons with carbon numbers of 3 to 13. As is clear from a comparison with the hydrocarbon distribution of Jet-A1 shown in Figure 4(a), the synthetic fuel obtained at a low linear velocity contains few hydrocarbons in the Jet range, and therefore is insufficient as hydrocarbons with the carbon number required for jet fuel components.

[0033] On the other hand, as shown in Figure 4(c), the synthetic fuel obtained at a high linear velocity contains hydrocarbons with carbon numbers of 4 to 20, and in particular contains a large amount of hydrocarbons in the Jet range, which has a carbon number of 8 to 16. This shows that the synthetic fuel obtained at a high linear velocity contains a sufficient amount of hydrocarbons with the carbon number required for jet fuel components.

[0034] 5 shows the relationship between the feed gas linear velocity and the jet fuel selectivity based on the test results described above. In the graph shown in the figure, the maximum value of the feed gas linear velocity in the test described above was 3.0, and the jet fuel selectivity at feed gas linear velocities of 3.0 to 4.0 m / sec is shown by a two-dot chain imaginary line. Furthermore, if the feed gas linear velocity exceeds 4.0 m / sec, the linear velocity of the feed gas supplied to the reactor 9 becomes too high, which may cause the FT catalyst 20 to become powdered (disintegrate), thereby adversely affecting the direct FT synthesis reaction. Therefore, the upper limit of the favorable linear velocity range in which the jet fuel selectivity is 40% or more is set to 4.0 m / sec.

[0035] From the graph shown in FIG. 5, it can be seen that the raw gas linear velocity at which a jet fuel selectivity of 40% or more and a relatively good jet fuel selectivity can be obtained is 0.2 to 4.0 m / sec (good linear velocity range).

[0036] It is also apparent that the feed gas linear velocity at which a relatively high jet fuel selectivity of 50% or more can be obtained is 2.7 to 3.0 m / sec (best linear velocity range).

[0037] Figure 6 shows the pore distributions, which represent the relationship between pore size and pore volume, for two types of FT catalysts C1 and C2, both of which have a large number of pores. As shown in the figure, the average pore size and median pore size of FT catalyst C1 are 31.5 and 38.6 nm, respectively, and the average pore size and median pore size of FT catalyst C2 are 25.5 and 20.7 nm, respectively. The pore distributions shown in Figure 6 were measured by a gas adsorption method using nitrogen.

[0038] The two types of FT catalysts C1 and C2 were packed into the reactor 9 of the synthetic fuel production apparatus 1 described above, and the feed gas was supplied to the reactor 9 at the same feed gas linear velocity, and the hydrocarbons obtained were compared. As a result, although detailed data is omitted, it was confirmed that high-boiling-point components, i.e., hydrocarbons with a large carbon number, were obtained with the FT catalyst C1, which had both a large average pore size and a large median pore size.

[0039] Furthermore, for an FT catalyst 20 having a large number of pores, the average diameter of the pores (average pore size) is preferably 10 to 100 nm, which can improve the yield of higher hydrocarbons with 8 or more carbon atoms, which are necessary for jet fuel. This is thought to be due to the following reason. Specifically, if the average pore size is less than 10 nm, it becomes difficult for the feed gas to reach deep into the pores in the FT catalyst 20, which may prevent the direct FT synthesis reaction from being sufficiently promoted. On the other hand, if the average pore size exceeds 100 nm, the surface area of ​​the FT catalyst 20 is reduced, which in turn reduces the amount of feed gas that comes into contact with the FT catalyst 20, which may prevent the yield of higher hydrocarbons with 8 or more carbon atoms, which are necessary for jet fuel, from being further improved. For these reasons, as described above, the average pore size of the FT catalyst 20 is preferably 10 to 100 nm.

[0040] As described above, according to this embodiment, when jet fuel is produced as a synthetic fuel, hydrocarbons with a high selectivity for jet fuel components can be obtained and jet fuel can be produced with a high yield by supplying a feed gas containing hydrogen and carbon dioxide to the reactor 9 filled with the FT catalyst 20 at a linear velocity of 0.2 to 4.0 m / sec. Furthermore, by setting the linear velocity to 2.7 to 3.0 m / sec, hydrocarbons with jet fuel components can be obtained with even higher selectivity.

[0041] The present invention is not limited to the above-described embodiment, and can be embodied in various forms. For example, in the embodiment, a catalyst containing Fe, Zr, Ga, and Na is used as the FT catalyst 20 for causing the direct FT synthesis reaction, but other catalysts can also be used as long as they can cause the direct FT synthesis reaction in a raw material gas containing hydrogen and carbon dioxide.

[0042] Furthermore, the detailed configuration of the synthetic fuel production device 1 shown in the embodiment is merely an example and can be modified as appropriate within the scope of the spirit of the present invention.

[0043] 1 Synthetic fuel production device 2 Piping 3 Control device (control means) 4a H ２ Supply section 4b CO ２ Supply section 5a H ２ Composition adjustment section 5b CO ２ Composition adjusting section 6 Compressor 7 Raw material gas flow rate adjusting section (flow rate adjusting section) 8a Preheating tube 8b Preheater 9 Reactor 9a Reactor main body 10 Temperature adjusting section 11 Cooler 12 Gas-liquid separator 13 Collection tank 20 FT catalyst

Claims

1. A synthetic fuel production apparatus for producing a specified synthetic fuel by a direct FT synthesis reaction using a raw material gas containing hydrogen and carbon dioxide, comprising: a reactor having a cylindrical reactor main body, the reactor main body being filled with a specified FT catalyst for causing the direct FT synthesis reaction; an adjustment unit for adjusting the flow rate of the raw material gas supplied to the reactor; and control means for controlling the linear velocity, which is the flow rate of the raw material gas per cross-sectional area of ​​the reactor main body, by controlling this adjustment unit, wherein the control means controls the linear velocity to 0.2 to 4.0 m / sec when the specified synthetic fuel is jet fuel.

2. The synthetic fuel production apparatus according to claim 1, wherein said control means controls said linear velocity to 2.7 to 3.0 m / sec.

3. A method for producing a synthetic fuel for producing a specified synthetic fuel by a direct FT synthesis reaction using a feed gas containing hydrogen and carbon dioxide, comprising: a reactor preparation step of preparing a reactor having a cylindrical reactor main body filled with a specified FT catalyst for causing the direct FT synthesis reaction; and a feed gas supply step of supplying the feed gas to the reactor so that the linear velocity, which is the flow rate of the feed gas per cross-sectional area of ​​the reactor main body, is 0.2 to 4.0 m / sec when the specified synthetic fuel is jet fuel.