WO2024257434A1 - Apparatus and method for producing synthetic fuel - Google Patents

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 apparatus and production method

The present invention relates to a synthetic fuel manufacturing apparatus and method for producing a specific synthetic fuel, particularly jet fuel, by a direct FT synthesis reaction using a raw material gas containing hydrogen and carbon dioxide.

　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 method for producing jet fuel, a chemical reaction is used to synthesize alkanes from synthesis gas in a reactor filled with an FT catalyst for causing the FT synthesis reaction, and FT crude oil containing a variety of hydrocarbons is produced. Then, by combining multiple hydrogenation, alkylation, and aromatization processes with this FT crude oil, a high yield of synthetic fuel suitable for jet fuel is achieved.

In addition, in recent years, research has been conducted into a direct FT synthesis method in which FT synthesis is performed using carbon dioxide instead of carbon monoxide in synthetic gas, with the aim of achieving carbon neutrality. In Patent Application No. 2022-052774, already filed by the applicant, an FT catalyst is proposed 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 raw material gas. This FT catalyst is composed of catalytic metals containing Fe (iron) and Zr (zirconium), Ga (gallium), and Na (sodium).

Patent No. 5826488

However, the above-mentioned FT catalyst does not provide sufficient selectivity for synthetic fuel suitable for jet fuel, specifically synthetic fuel containing hydrocarbons with 8 to 16 carbon atoms, in the synthetic fuel produced. After extensive research, the inventors discovered that it is possible to increase the selectivity for hydrocarbons with a desired carbon number based on the relationship between the FT catalyst packed in the reactor and the flow rate and flow speed of the raw material gas supplied to the reactor, and thus completed the present invention.

The present invention has been made to solve the above problems, and aims to provide a synthetic fuel production device and method that can obtain a specific synthetic fuel, particularly hydrocarbons with a high selectivity for jet fuel components, and produce jet fuel with a high yield.

In order to achieve the above object, the invention of claim 1 is a synthetic fuel production device (synthetic fuel production device 1 in this embodiment (hereinafter the same in this section)) for producing a specified synthetic fuel by a direct FT synthesis reaction using a raw material gas containing hydrogen and carbon dioxide, and is equipped with a reactor 9 having a cylindrical reactor main body 9a and filled with a specified FT catalyst 20 for causing a direct FT synthesis reaction in the reactor main body, an adjustment unit (raw material gas flow rate adjustment unit 7 and/or composition adjustment units 5a, 5b) for adjusting the flow rate of the raw material gas supplied to the reactor, and a control means (control device 3) 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, and the control means is characterized in that when the specified synthetic fuel is jet fuel, the linear velocity is controlled to 0.2 to 4.0 m/sec.

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

The invention according to claim 2 is the synthetic fuel production device according to claim 1, characterized in that the control means controls the linear velocity to 2.7 to 3.0 m/sec.

With this configuration, the linear velocity can be controlled to 2.7 to 3.0 m/sec by the control means, making it possible to obtain jet fuel component hydrocarbons with a higher selectivity.

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

According to this configuration, when a specified synthetic fuel is produced by a direct FT synthesis reaction using a feed gas containing hydrogen and carbon dioxide, first, a reactor is prepared with a specified FT catalyst packed in the cylindrical reactor body (reactor preparation process). Next, when the specified 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 body, is 0.2 to 4.0 m/sec (feed gas supply process). By supplying the feed gas to the reactor at a linear velocity within the above range, it is possible to produce the specified synthetic fuel, particularly a synthetic fuel containing hydrocarbons with a high selectivity for jet fuel components.

1 is a diagram showing a schematic diagram of a synthetic fuel production apparatus to which a synthetic fuel production apparatus and production method according to an embodiment of the present invention are applied. FIG. 2A is a diagram showing a reactor packed with an FT catalyst, and FIG. 2B is a diagram for explaining the linear velocity of a raw material gas supplied to the reactor. 1 is a graph showing the distillation properties of synthetic fuels obtained when the feed gas is supplied to a reactor at a high linear velocity and a low linear velocity. 1 is a graph showing a hydrocarbon distribution indicating the relationship between the carbon number and weight of the hydrocarbons contained in a synthetic fuel, in which (a) shows the hydrocarbon distribution of a Jet-A1 standard jet fuel, (b) shows the hydrocarbon distribution of a synthetic fuel obtained at a low linear velocity, and (c) shows the hydrocarbon distribution of a synthetic fuel obtained at a high linear velocity. 1 is a graph showing the relationship between the feed gas linear velocity and the jet fuel selectivity based on test results. 1 is a graph showing the pore distribution, which indicates the relationship between pore size and pore volume, for two types of FT catalysts.

Below, preferred embodiments of the present invention will be described in detail with reference to the drawings. Figure 1 shows a schematic diagram of 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 comprises 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 are controlled by a control device 3 (control means).

The raw material gas supply unit has an _H2 supply unit 4a and a _CO2 supply unit 4b, which supply hydrogen and carbon dioxide, respectively. In addition, an _H2 composition adjustment unit 5a and a _CO2 composition adjustment unit 5b are provided downstream of the _H2 supply unit 4a and the _CO2 supply unit 4b, respectively. By controlling these, the composition and mixture ratio of the mixed gas of _H2 and _CO2 supplied as raw material gas to a reactor 9 of the catalytic reaction unit described later are adjusted. In addition, these _H2 composition adjustment units 5a and _CO2 composition adjustment units 5b are controlled by the control device 3, and can adjust the flow rate of the raw material gas alone or in cooperation with a raw material gas flow rate adjustment unit 7 described later.

The compression section 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 section has a raw material gas flow rate adjustment section 7, and is controlled by the control device 3 to adjust the flow rate of the raw material gas compressed by the compressor 6.

The preheating section has a preheating tube 8a and a preheater 8b, and the preheater 8b is controlled by the control device 3, so that the raw material gas passing through the preheating tube 8a connected to the piping 2 is heated to a predetermined temperature.

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 body 9a having a predetermined inner diameter, and the reactor body 9a is filled with the FT catalyst 20. The preparation of the reactor 9 by filling the reactor body 9a with the FT catalyst 20 corresponds to the reactor preparation step in the synthetic fuel production method 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.

The FT catalyst 20 is for producing a plurality of types of hydrocarbons having 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 composed of a large number of pellets each having a predetermined size and shape, and each is configured to have a large number of pores. These pores have a specific surface area of about 30 m ² /g and an average pore diameter of 10 to 100 nm.

The temperature adjustment unit 10 in the catalytic reaction section is controlled by the control device 3, and the direct FT synthesis reaction occurring in the reactor 9 is adjusted to a predetermined temperature (e.g., 380°C).

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

The cooling section has a cooler 11, and the product discharged from the reactor 9 is cooled by controlling the cooler 11 with the control device 3.

The gas-liquid separation section has a gas-liquid separator 12, which separates the product that has been liquefied by cooling in the cooler 11 from the gaseous post-reaction gas that has not reacted or has not been liquefied. Although the above-mentioned post-reaction gas is discharged outside the synthetic fuel production device 1, it is effectively reused as a raw material gas for other refining processes or chemical reactions.

The collection section has a collection tank 13, which collects the liquid product separated by the gas-liquid separator 12.

In the synthetic fuel production device 1 configured as described above, as shown below, by causing a direct FT synthesis reaction while controlling the linear velocity of the raw material 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.

The linear velocity is the flow rate of the raw material gas per inner cross-sectional area 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 gas flow rate (m ³ /sec)/cross-sectional area (m ² )

Figure 3 shows the results of a distillation test of the synthetic fuel obtained by using the synthetic fuel production device 1 to supply raw material 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 causing a direct FT synthesis reaction under specified conditions (reactor temperature: 380°C, reactor pressure: 3 MPa), with the horizontal axis showing the distillate amount (wt%) and the vertical axis showing the distillate temperature (°C). Note that the distillate temperatures TH and TL in the figure respectively indicate the upper and lower limit distillation temperatures suitable for jet fuel components, and specifically, for example, the upper limit distillation temperature TH is 232°C and the lower limit distillation temperature TL is 157°C.

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

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

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

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

In contrast, as shown in Figure 4(b), the synthetic fuel obtained at low linear velocity contains hydrocarbons with carbon numbers between 3 and 13. As is clear from a comparison with the hydrocarbon distribution of Jet-A1 shown in Figure 4(a), the synthetic fuel obtained at 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.

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

Figure 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 feed gas linear velocity in the test described above is 3.0, and the Jet fuel selectivity for feed gas linear velocities of 3.0 to 4.0 m/sec is shown by a two-dot chain imaginary line. Also, 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.

The graph in Figure 5 shows that the feed 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).

It can also be seen 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).

Figure 6 shows the pore distributions, which indicate 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.

The above two types of FT catalysts C1 and C2 were loaded into the reactor 9 of the synthetic fuel production device 1 described above, and the raw material gas was supplied to the reactor 9 at the same raw material gas linear velocity, and the resulting hydrocarbons 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 has both a large average pore diameter and a large median pore diameter.

Furthermore, for the FT catalyst 20 having a large number of pores, it is preferable that the average diameter of the pores (average pore diameter) is 10 to 100 nm, which can improve the yield of higher hydrocarbons with 8 or more carbon atoms required for jet fuel. This is believed to be due to the following reasons. That is, if the average pore diameter is less than 10 nm, the raw material gas will have difficulty reaching deep into the pores in the FT catalyst 20, and there is a risk that the direct FT synthesis reaction will not be sufficiently promoted. On the other hand, if the average pore diameter exceeds 100 nm, the surface area of the FT catalyst 20 will be reduced, and the amount of raw material gas in contact with the FT catalyst 20 will also be reduced, which may prevent the yield of higher hydrocarbons with 8 or more carbon atoms required for jet fuel from being further improved. For these reasons, as described above, it is preferable that the average pore diameter of the FT catalyst 20 is 10 to 100 nm.

As described above, according to this embodiment, when producing jet fuel as a synthetic fuel, a raw material gas containing hydrogen and carbon dioxide is supplied to the reactor 9 filled with the FT catalyst 20 at a linear velocity of 0.2 to 4.0 m/sec, which makes it possible to obtain hydrocarbons with a high selectivity for jet fuel components and produce jet fuel with a high yield. In addition, by setting the linear velocity to 2.7 to 3.0 m/sec, it is possible to obtain hydrocarbons of jet fuel components with a higher selectivity.

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

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.

1 Synthetic fuel production device 2 Pipe 3 Control device (control means)
4a _H2 supply unit 4b _CO2 supply unit 5a _H2 composition adjustment unit 5b _CO2 composition adjustment unit 6 Compressor 7 Raw material gas flow rate adjustment unit (flow rate adjustment unit)
8a Preheating tube 8b Preheater 9 Reactor 9a Reactor main body 10 Temperature adjustment section 11 Cooler 12 Gas-liquid separator 13 Collection tank 20 FT catalyst

Claims (3)

A synthetic fuel production apparatus for producing a predetermined synthetic fuel by a direct FT synthesis reaction using a raw material gas containing hydrogen and carbon dioxide,
a reactor having a cylindrical reactor main body, the reactor main body being filled with a predetermined FT catalyst for causing the direct FT synthesis reaction;
an adjusting unit for adjusting a flow rate of the raw material gas supplied to the reactor;
a 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 the adjusting unit;
Equipped with
The synthetic fuel manufacturing apparatus is characterized in that the control means controls the linear velocity to 0.2 to 4.0 m/sec when the predetermined synthetic fuel is jet fuel. The synthetic fuel production device according to claim 1, characterized in that the control means controls the linear velocity to 2.7 to 3.0 m/sec. A method for producing a synthetic fuel by a direct FT synthesis reaction using a raw material gas containing hydrogen and carbon dioxide, comprising:
a reactor preparation step of preparing a reactor having a cylindrical reactor main body filled with a predetermined FT catalyst for causing the direct FT synthesis reaction;
a raw material gas supplying step of supplying the raw material gas to the reactor so that a linear velocity, which is a flow rate of the raw material 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;
A method for producing synthetic fuel, comprising:

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