reactor

Abstract

The reactor (1) of the present invention comprises: a separation membrane (10) that allows water vapor to pass through; a non-permeable side flow path (30) extending in a substantially vertical direction on the non-permeable side of the separation membrane (10); and a catalyst (60) filled in the non-permeable side flow path (30). The catalyst (60) comprises a first layer (61) disposed at the lower end of the non-permeable side flow path (30) and a second layer (62) disposed above the first layer (61). The average equivalent circular diameter of the catalyst particles contained in the first layer (61) is larger than the average equivalent circular diameter of the catalyst particles contained in the second layer (62).

Description

Technical Field

[0001] The present invention relates to a reactor. Background Art

[0002] In recent years, reactors have been developed that can improve conversion efficiency by separating products of a conversion reaction from a feed gas containing hydrogen and carbon oxides to a liquid fuel such as methanol or ethanol (specifically, a fuel that is liquid at room temperature and pressure).

[0003] For example, Patent Document 1 discloses a reactor comprising: a separation membrane that allows water vapor, a product of a reforming reaction, to pass through; a non-permeable flow path through which a feed gas flows; and a catalyst filled within the flow path. The catalyst promotes the reforming reaction from the feed gas to liquid fuel.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2018-8940 Summary of the Invention

[0007] Problems to be solved by the invention

[0008] In the reactor described in Patent Document 1, since the non-permeate-side flow path extends in the vertical direction, the weight of the catalyst acts on the separation membrane at the lower end of the non-permeate-side flow path, potentially damaging the separation membrane.

[0009] An object of the present invention is to provide a reactor capable of suppressing damage to a separation membrane.

[0010] Means for solving problems

[0011] The reactor according to the present invention comprises: a separation membrane that allows permeation of the products of a reforming reaction from a feed gas containing at least hydrogen and carbon oxides to a liquid fuel; a non-permeable flow path extending substantially vertically on the non-permeable side of the separation membrane and through which the feed gas flows; and a catalyst filled within the non-permeable flow path to promote the reforming reaction. The catalyst comprises a first layer disposed at the lower end of the non-permeable flow path and a second layer disposed above the first layer. The catalyst particles contained in the first layer have a larger average equivalent circular diameter than the catalyst particles contained in the second layer.

[0012] Effects of the Invention

[0013] According to the present invention, a reactor capable of suppressing damage to a separation membrane can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a cross-sectional view of a reactor according to an embodiment.

[0015] Figure 2 It is a cross-sectional view of a catalyst according to a comparative example.

[0016] Figure 3 It is a cross-sectional view of a catalyst according to a comparative example.

[0017] Figure 4 It is a cross-sectional view of the catalyst according to the example.

[0018] Figure 5 It is a cross-sectional view of the catalyst according to the example.

[0019] Figure 6 It is a cross-sectional view of a reactor according to Modification 2.

[0020] Figure 7 It is a cross-sectional view of a reactor according to Modification 2. DETAILED DESCRIPTION

[0021] The embodiments of the present invention will be described with reference to the accompanying drawings. However, the drawings are schematic diagrams, and the ratios of various dimensions and the like may differ from the actual ones.

[0022] (Reactor 1)

[0023] Figure 1 is a cross-sectional view of the reactor 1.

[0024] The reactor 1 is a so-called membrane reactor for converting a raw gas into a liquid fuel. The structure of the reactor 1 can be applied to a fixed bed reactor or a monolithic reactor.

[0025] The raw material gas contains at least hydrogen and carbon oxide. As the carbon oxide, at least one of carbon monoxide and carbon dioxide can be used. The raw material gas may also be so-called synthesis gas (Syngas).

[0026] Liquid fuel is a fuel that is in liquid state at room temperature and pressure, or a fuel that can be liquefied at room temperature and pressure. Examples of fuel that is in liquid state at room temperature and pressure include methanol, ethanol, n H 2(m-2n) (m is an integer less than 90, n is an integer less than 30), and mixtures thereof. Examples of fuels that can be liquefied under normal temperature and pressure include propane, butane, and mixtures thereof.

[0027] For example, when methanol is synthesized by catalytic hydrogenation of a raw material gas containing carbon dioxide and hydrogen in the presence of a catalyst, the reaction formula (1) is as follows.

[0028]

[0029] The above reaction is an equilibrium reaction. To improve both conversion efficiency and reaction rate, it is preferably carried out at high temperature and high pressure (e.g., 180°C or higher, 2 MPa or higher). The liquid fuel is in a gaseous state at the time of synthesis and remains in this state at least until it exits reactor 1. Reactor 1 preferably has heat and pressure resistance suitable for the desired liquid fuel synthesis conditions.

[0030] like Figure 1 As shown, the reactor 1 includes a separation membrane 10 , a porous support 20 , a non-permeate-side flow channel 30 , a permeate-side flow channel 40 , an outer tube 50 , and a catalyst 60 .

[0031] The separation membrane 10 allows water vapor, one of the products of the conversion reaction from the raw gas to the liquid fuel, to permeate. This allows the reaction equilibrium of the above-mentioned formula (1) to shift toward the product side by utilizing the equilibrium shift effect. In this embodiment, the separation membrane 10 is formed into a cylindrical shape.

[0032] The separation membrane 10 preferably has a thermal conductivity of 100 nmol / (s·Pa·m 2 ) or more. The water vapor permeability coefficient can be determined by a known method (see Ind. Eng. Chem. Res., 40, 163-175 (2001)).

[0033] The separation membrane 10 preferably has a separation factor of 100 or greater. A larger separation factor allows water vapor to pass through more easily, while components other than water vapor (such as hydrogen, carbon dioxide, and liquid fuel) are less likely to pass through. The separation factor can be determined using known methods (see Fig. 1 of "Separation and Purification Technology 239(2020)116533").

[0034] The separation membrane 10 is formed in a cylindrical shape and is disposed inside a cylindrical porous support 20 . The separation membrane 10 is in contact with the inner peripheral surface of the porous support 20 .

[0035] As the separation membrane 10, an inorganic membrane can be used. Inorganic membranes are preferred because they have heat resistance, pressure resistance, and water vapor resistance. Examples of inorganic membranes include zeolite membranes, silica membranes, alumina membranes, and composite membranes thereof. In particular, LTA-type zeolite membranes having a molar ratio (Si / Al) of silicon (Si) to aluminum (Al) of 1.0 to 3.0 are preferred because of their excellent water vapor permeability. However, inorganic membranes have the characteristic of being easily damaged by thermal shock.

[0036] The porous support 20 is formed in a cylindrical shape. The porous support 20 surrounds the separation membrane 10. The porous support 20 supports the separation membrane 10. The porous support 20 is made of a porous material. In this embodiment, the porous support 20 is formed in a cylindrical shape.

[0037] As the porous material, ceramic materials, metal materials, resin materials, etc. can be used, and ceramic materials are particularly preferred. As the aggregate of the ceramic material, for example, alumina (Al2O3), titanium dioxide (TiO2), mullite (Al2O3·SiO2), ceramic particles, and cordierite (Mg2Al4Si5O 18 ). As the inorganic binder for the ceramic material, for example, at least one of titanium dioxide, mullite, sinterable alumina, silicon dioxide, glass powder, clay mineral, and sinterable cordierite can be used. However, the ceramic material does not necessarily need to contain an inorganic binder.

[0038] The non-permeate-side flow path 30 is provided on the non-permeate side of the separation membrane 10. In the present embodiment, the non-permeate-side flow path 30 is a columnar space inside the separation membrane 10.

[0039] The non-permeate-side flow path 30 extends in a substantially vertical direction. The term "substantially vertical direction" includes not only a direction that coincides with the direction of gravity but also a direction that is slightly inclined (±15 degrees) relative to the direction of gravity.

[0040] The raw material gas flows through the non-permeated-side flow path 30. In this embodiment, the raw material gas flows downward within the non-permeated-side flow path 30. Therefore, the raw material gas flows in through the upper end opening 30a of the non-permeated-side flow path 30, and the liquid fuel flows out through the lower end opening 30b of the non-permeated-side flow path 30. However, the raw material gas may also flow upward within the non-permeated-side flow path 30. Excess raw material gas may also be mixed with the liquid fuel flowing out through the lower end opening 30b.

[0041] The permeate-side flow path 40 is provided on the non-permeate side of the separation membrane 10. In this embodiment, the permeate-side flow path 40 is an annular space between the separation membrane 10 and the outer tube 50. Water vapor that has permeated the separation membrane 10 flows into the permeate-side flow path 40.

[0042] In this embodiment, a purge gas for purging water vapor flows through the permeate-side flow channel 40. The purge gas can be an inert gas (e.g., nitrogen) or air. In this embodiment, the purge gas flows upward (i.e., in the opposite direction to the feed gas) within the permeate-side flow channel 40. Therefore, the purge gas flows in through the lower opening 40a of the permeate-side flow channel 40, and the purge gas, which has taken in water vapor, flows out through the upper opening 40b of the permeate-side flow channel 40. However, the purge gas may also flow downward (i.e., in the same direction as the feed gas) within the permeate-side flow channel 40.

[0043] The catalyst 60 is filled in the non-permeate side flow path 30 . The catalyst 60 advances (accelerates) the conversion reaction from the raw gas to the liquid fuel. The catalyst 60 is in direct contact with the separation membrane 10 .

[0044] The catalyst 60 is composed of a plurality of catalyst particles. The catalyst particles are composed of a carrier and a supported catalyst component. Examples of the carrier include, but are not limited to, alumina, titania, silica, ceria, and zeolite. The supported catalyst component is supported on the surface of the carrier. Examples of the supported catalyst component include, but are not limited to, metal catalyst components (such as copper and palladium), oxide catalyst components (such as zinc oxide, amorphous zirconium oxide, and gallium oxide), and composites thereof.

[0045] The shape of the catalyst particles is not particularly limited, and may be, for example, spherical, ellipsoidal, cylindrical, elliptical columnar, disc-shaped, scaly, needle-shaped, polygonal columnar, or flake-shaped.

[0046] The catalyst 60 has a multilayer structure in which a plurality of layers are stacked in a substantially vertical direction. In the present embodiment, the catalyst 60 has a two-layer structure having a first layer 61 and a second layer 62 .

[0047] The first layer 61 is located at the bottom of the catalyst 60. The first layer 61 is disposed at the lower end of the non-permeate-side flow path 30. The lower end of the non-permeate-side flow path 30 refers to a region below the center of the non-permeate-side flow path 30 in a substantially vertical direction.

[0048] The second layer 62 is arranged above the first layer 61. In this embodiment, the catalyst 60 has a two-layer structure, and the second layer 62 is arranged on the first layer 61. The second layer 62 is arranged in a region of the non-permeate-side flow path 30 where the first layer 61 is not arranged.

[0049] Here, the average equivalent circular diameter (mean circular diameter) of the catalyst particles included in the first layer 61 is larger than the average equivalent circular diameter of the catalyst particles included in the second layer 62. This prevents the weight of the catalyst 60 from acting on the separation membrane 10 and causing damage to the separation membrane 10. The mechanism for preventing damage to the separation membrane 10 is as follows.

[0050] First, in Figure 2 as well as Figure 3 , a comparative example is schematically shown in which the average equivalent circle diameter of the catalyst particles included in the first layer 61 is equal to the average equivalent circle diameter of the catalyst particles included in the second layer 62. Figure 2 The figure shows the case where the catalyst particles are spherical. Figure 3 The figure shows the case where the catalyst particles are cylindrical. Figure 2 as well as Figure 3 In this embodiment, the catalyst particles contained in the first layer 61 and the catalyst particles contained in the second layer 62 are easily displaced in the horizontal direction. Therefore, when the force F1 applied to the catalyst particles contained in the first layer 61 is decomposed into a horizontal component F2 and a vertical component F3, the horizontal component F2 is large. As a result, a large force is applied to the separation membrane 10 from the catalyst particles contained in the first layer 61, which is likely to damage the separation membrane 10.

[0051] On the other hand, Figure 4 as well as Figure 5 , an embodiment is schematically illustrated in which the average equivalent circular diameter of the catalyst particles included in the first layer 61 is larger than the average equivalent circular diameter of the catalyst particles included in the second layer 62. Figure 4 The figure shows the case where the catalyst particles are spherical. Figure 5 The figure shows the case where the catalyst particles are cylindrical. Figure 4 as well as Figure 5 In the embodiment, the positional deviation in the horizontal direction between the catalyst particles included in the first layer 61 and the catalyst particles included in the second layer 62 can be suppressed, so that the horizontal component F20 when the force F10 applied to the catalyst particles included in the first layer 61 is decomposed into the horizontal component F20 and the vertical component F30 can be made smaller. Figure 2 as well as Figure 3 The horizontal component F2 shown is small. As a result, the force applied to the separation membrane 10 from the catalyst particles included in the first layer 61 can be reduced, thereby suppressing damage to the separation membrane 10.

[0052] Furthermore, since the average equivalent circle diameter of the catalyst particles included in the second layer 62 is relatively small, the filling rate of the catalyst particles can be increased, thereby increasing the total surface area, thereby enabling a larger amount of supported catalyst components to be supported. As a result, the catalytic performance of the catalyst 60 as a whole can be ensured.

[0053] The average equivalent circle diameter is calculated as follows.

[0054] First, a resin (eg, epoxy) is flowed into the non-permeate-side flow channel 30 and cured, and then the catalyst 60 is cut in a substantially vertical direction.

[0055] Next, a cross-sectional image of each of the first layer 61 and the second layer 62 is obtained using an SEM (scanning electron microscope). The SEM magnification is selected from a range of 1x to 100x so that 10 or more (preferably 100 or more) catalyst particles can be observed in one field of view. In this case, if the two cross-sections of the separation membrane (the cross-sections on both sides of the non-permeate-side flow path 30 in the horizontal direction) do not fit within a single field of view, the separation membrane cross-section can be observed in two fields of view and in one or more fields of view between the two fields of view.

[0056] Next, SEM-EDS (energy dispersive X-ray analysis) is used to identify the elements of the material exposed in the cross-sections of each of the first layer 61 and the second layer 62, thereby identifying the catalyst particles in the cross-sectional images of each of the first layer 61 and the second layer 62. The method for identifying the catalyst particles is not limited to the method using SEM-EDS; for example, a method using WDS (wavelength dispersive X-ray analysis) may also be employed.

[0057] Next, the arithmetic mean of the equivalent circular diameters of at least 30 catalyst particles randomly selected from the cross-sectional image of the first layer 61 is calculated, and the arithmetic mean of the equivalent circular diameters of at least 30 catalyst particles randomly selected from the cross-sectional image of the second layer 62 is calculated. The arithmetic mean of the first layer 61 thus calculated is the average equivalent circular diameter of the catalyst particles contained in the first layer 61, and the arithmetic mean of the second layer 62 is the average equivalent circular diameter of the catalyst particles contained in the second layer 62. The equivalent circular diameter of the catalyst particles refers to the diameter of a circle having the same area as the catalyst particles.

[0058] The average equivalent circular diameter of the catalyst particles contained in the first layer 61 is not particularly limited and can be, for example, 1000 μm or greater and 10,000 μm or less. Furthermore, reducing the average equivalent circular diameter of the catalyst particles in the first layer 61 increases pressure drop variation, leading to gas flow deviation. Therefore, the average equivalent circular diameter of the catalyst particles in the first layer 61 is preferably 500 μm or greater. Furthermore, tensile stress is easily applied to the separation membrane 10 disposed inside the porous support 20. However, by setting the average equivalent circular diameter of the catalyst particles in the first layer 61 to 500 μm or greater, the application of stress to the separation membrane 10 can be suppressed.

[0059] The average equivalent circular diameter of the catalyst particles contained in the second layer 62 is not particularly limited and can be, for example, 6000 μm or less. Furthermore, if the average equivalent circular diameter of the catalyst particles in the second layer 62 is reduced, the pressure loss will vary, leading to gas flow deviation. Therefore, the average equivalent circular diameter of the catalyst particles in the second layer 62 is preferably 500 μm or greater. Furthermore, tensile stress is easily applied to the separation membrane 10 disposed inside the porous support 20. However, by setting the average equivalent circular diameter of the catalyst particles in the second layer 62 to 500 μm or greater, the stress applied to the separation membrane 10 can be suppressed.

[0060] The catalyst 60 can be formed by placing catalyst particles for the first layer 61 from above the non-permeate-side flow channel 30 and then placing catalyst particles for the second layer 62 from above the non-permeate-side flow channel 30 .

[0061] (Modification of the embodiment)

[0062] As mentioned above, although one embodiment of the present invention has been described, the present invention is not limited to the above embodiment, and various modifications can be made without departing from the scope of the invention.

[0063] (Variation 1)

[0064] In the above embodiment, the inner side of the separation membrane 10 is set as the non-permeate side flow path 30, and the outer side of the separation membrane 10 is set as the permeate side flow path 40. However, the outer side of the separation membrane 10 may be set as the non-permeate side flow path 30, and the inner side of the separation membrane 10 may be set as the permeate side flow path 40. In this case, it is preferable to form the separation membrane 10 so as to surround the outer side of the porous support 20.

[0065] (Variation 2)

[0066] In the above embodiment, the catalyst 60 is configured to have a two-layer structure including a first layer 61 and a second layer 62, but may also have a structure including three or more layers. Figure 6 as well as Figure 7 As shown, the catalyst 60 can be formed into a three-layer structure including a third layer 63 in addition to the first layer 61 and the second layer 62 .

[0067] exist Figure 6In the embodiment, the third layer 63 is arranged substantially vertically between the first layer 61 and the second layer 62. The average equivalent circular diameter of the catalyst particles contained in the third layer 63 is preferably smaller than the average equivalent circular diameter of the catalyst particles contained in the first layer 61 and larger than the average equivalent circular diameter of the catalyst particles contained in the second layer 62. This further reduces the force exerted on the separation membrane 10 by the catalyst particles contained in the first layer 61, thereby further suppressing damage to the separation membrane 10. Furthermore, the force exerted on the separation membrane 10 by the catalyst particles contained in the third layer 63 can be reduced, thereby expanding the range within which damage to the separation membrane 10 can be suppressed.

[0068] Furthermore, other layers may be disposed between the first layer 61 and the third layer 63, and between the second layer 62 and the third layer 63. The average equivalent circle diameter of the catalyst particles contained in each layer preferably increases with increasing diameter in the lower layer and decreases with increasing diameter in the upper layer.

[0069] exist Figure 7 , the third layer 63 is arranged below the first layer 61 in a substantially vertical direction. The third layer 63 contains at least one of catalyst particles and filler particles. The filler particles may not have a catalytic function. The filler particles can be composed of, for example, ceramic materials (alumina, titanium dioxide, silicon dioxide, ceria, zeolite, etc.). In the case where the third layer 63 contains catalyst particles, the average equivalent circular diameter of the catalyst particles contained in the third layer 63 may be greater than or smaller than the average equivalent circular diameter of the catalyst particles contained in the first layer, or they may be the same. In addition, in the case where the third layer 63 contains filler particles, the average equivalent circular diameter of the filler particles contained in the third layer 63 may be greater than or smaller than the average equivalent circular diameter of the catalyst particles contained in the first layer, or they may be the same.

[0070] Thus, even when the first layer 61 is not arranged at the bottom layer, damage to the portion of the separation membrane 10 that contacts the first layer 61 can be suppressed. However, if the average equivalent circle diameter of the catalyst particles or filler particles included in the third layer 63 is small, damage to the portion of the separation membrane 10 that contacts the third layer 63 may occur. Therefore, it is preferable to arrange the first layer 61 at the bottom layer.

[0071] (Variation 3)

[0072] In the above embodiment, the separation membrane 10 is configured to allow water vapor, a product of the conversion reaction from the raw gas to the liquid fuel, to pass through, but the present invention is not limited thereto. The separation membrane 10 may also allow the liquid fuel itself, a product of the conversion reaction from the raw gas to the liquid fuel, to pass through. In this case, the reaction equilibrium of the above formula (1) can also be shifted toward the product side.

[0073] Furthermore, in the case where the separation membrane 10 allows liquid fuel to permeate, even if the separation membrane 10 is subjected to a reaction that does not generate water vapor (e.g., ) to generate liquid fuel, the reaction equilibrium can also be shifted toward the product side.

[0074] Explanation of symbols

[0075] 1: Reactor

[0076] 10: Separation membrane

[0077] 20: Porous support

[0078] 30: Non-permeable side flow path

[0079] 30a: Open at the top

[0080] 30b: Open at the bottom

[0081] 40: Through the side flow path

[0082] 40a: Open at the bottom

[0083] 40b: Open top

[0084] 50: External tube

[0085] 60: Catalyst

[0086] 61: First floor

[0087] 62: Second floor

[0088] 63: The third floor.

Claims

1. A reactor comprising: External control; a separation membrane that allows a product generated by a conversion reaction of a raw gas containing at least hydrogen and carbon oxides into a liquid fuel to permeate; a permeate-side flow path provided on the permeate side of the separation membrane; a non-permeate-side flow path extending in a substantially vertical direction on the non-permeate side of the separation membrane and through which the raw material gas flows; and A catalyst is filled in the non-permeable side flow path to enable the conversion reaction to proceed. The catalyst includes a first layer and a second layer disposed above the first layer. The average equivalent circular diameter of the catalyst particles included in the first layer is larger than the average equivalent circular diameter of the catalyst particles included in the second layer, The separation membrane is cylindrical and is disposed inside or outside a cylindrical porous support. The separation membrane is in contact with the porous support. The non-permeable side flow path is a columnar space inside the separation membrane, and the permeable side flow path is an annular space between the separation membrane and the outer tube. The first layer is located at the bottom of the catalyst. The average equivalent circle diameter of the catalyst particles included in the first layer is 500 μm or more, and the average equivalent circle diameter of the catalyst particles included in the second layer is 500 μm or more, The raw material gas flows in from the upper end opening of the non-permeate-side flow path.

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