Membrane reactor

Abstract

Provided is a membrane reactor capable of improving the production efficiency of a target compound. A membrane reactor according to an embodiment of the present invention has a flow passage. A fluid can pass through the flow passage. This membrane reactor comprises a catalyst, a separation membrane, and a current-changing unit. The catalyst is disposed so as to be able to contact the fluid passing through the flow passage. The catalyst can promote the conversion reaction of a raw material component contained in the fluid. The separation membrane can transmit a reaction product generated by the conversion reaction of the raw material component. The current-changing unit is arranged in at least a part of the flow passage. The current-changing unit changes a part of the flow of the fluid passing through the flow passage toward the separation membrane.

Description

Membrane Reactor

[0001] The present invention relates to a membrane reactor.

[0002] In recent years, with the aim of realizing a carbon-neutral society, carbon oxides such as carbon monoxide and carbon dioxide have been considered as carbon resources, and studies have been made to convert them into useful industrial products (e.g., raw materials for chemical products, synthetic fuels, and synthetic gasoline raw materials) as basic industrial raw materials. For example, carbon dioxide (CO ２ ) and hydrogen (H ２ It has been proposed to produce methanol, which can be suitably used for various applications, by reacting ethanol with ethanol.

[0003] Such a reaction between carbon oxide and hydrogen is typically an equilibrium reaction, and water may be produced. Therefore, methods have been proposed for removing the produced water from the reaction system to promote the chemical reaction by using an equilibrium shift effect. For example, a separation membrane reactor has been proposed, which includes a first space on the non-permeation side into which a feed gas containing carbon dioxide and hydrogen is introduced, a water vapor separation membrane, a second space on the permeation side, and a catalyst disposed in the first space, and which promotes the conversion reaction of the feed gas to methanol through the action of the catalyst (see Patent Document 1). In such a separation membrane reactor, water vapor generated by the conversion reaction passes through the water vapor separation membrane and flows into the second space, where it is removed from the first space into which the feed gas is introduced.

[0004] JP 2018-008940 A

[0005] There is an increasing demand for improved production efficiency of target compounds in separation membrane reactors such as that described in Patent Document 1. A primary object of the present invention is to provide a membrane reactor that can improve the production efficiency of target compounds.

[0006] [1] A membrane reactor according to one embodiment of the present invention has a flow path. A fluid can pass through the flow path. The membrane reactor includes a catalyst, a separation membrane, and a flow-diverting section. The catalyst is arranged so as to be in contact with the fluid passing through the flow path. The catalyst can promote a conversion reaction of raw material components contained in the fluid. The separation membrane is permeable to reaction products produced by the conversion reaction of the raw material components. The flow-diverting section is arranged in at least a portion of the flow path. The flow-diverting section diverts a portion of the flow of the fluid passing through the flow path toward the separation membrane. [2] In the membrane reactor described in [1] above, the catalyst may be packed in the flow path. [3] In the membrane reactor described in [1] or [2] above, the flow-diverting section may contain the catalyst. [4] The membrane reactor described in any of [1] to [3] above may include a support substrate and a catalyst layer containing the catalyst. The support substrate supports the separation membrane. The catalyst layer is provided on the surface of the separation membrane opposite to the support substrate. [5] In the membrane reactor described in any one of [1] to [4] above, the flow diversion section may have a guide surface. The guide surface extends at various locations within the flow channel in a direction intersecting a central axis direction continuously connecting the centers of cross sections obtained by cutting the flow channel in a direction perpendicular to the flow channel from the upstream end to the downstream end of the flow channel. [6] In the membrane reactor described in [5] above, a catalyst layer containing the catalyst may be provided on the guide surface. [7] In the membrane reactor described in any one of [1] to [6] above, the flow diversion section may be a static mixer. [8] In the membrane reactor described in any one of [1] to [6] above, the flow diversion section may have a first tube passage. The first tube passage is capable of passing a fluid. The first tube passage is inclined so as to approach the separation membrane as it moves downstream in the direction of fluid passage. [9] In the membrane reactor described in [8] above, the first tube passage may be filled with the catalyst.

[10] In the membrane reactor described in [8] above, a catalyst layer containing the catalyst may be provided on the inner surface of the first tube passage.

[11] In the membrane reactor described in any one of [8] to

[10] above, the flow transformer may have a second tube passage. The second tube passage is capable of passing a fluid.The second tube passage may be inclined so as to approach the central axis of the flow path toward the downstream side in the fluid passage direction.

[12] In the membrane reactor described in

[11] above, the second tube passage may be filled with the catalyst.

[13] In the membrane reactor described in

[11] or

[12] above, a catalyst layer containing the catalyst may be provided on the inner surface of the second tube passage.

[14] The membrane reactor described in any of

[11] to

[13] above may further include a plurality of flow diversion sections and a tubular member. The plurality of flow diversion sections are arranged at intervals in the central axis direction. The tubular member is arranged between adjacent flow diversion sections among the plurality of flow diversion sections. The tubular member divides the flow path into an inner region including the central axis of the flow path and an outer region in which the separation membrane is located.

[15] In the membrane reactor according to any one of [1] to

[14] above, when the total length of the flow channel is taken as 100%, the proportion of the area where the flow diversion section is arranged may be 1% or more.

[16] The membrane reactor according to

[15] above may include a plurality of flow diversion sections arranged at intervals from each other in the central axis direction. The sum of the dimensions of the plurality of flow diversion sections in the direction of extension of the flow channel may be 1% or more and 99% or less of the total length of the flow channel (100%).

[17] In the membrane reactor according to any one of [1] to

[16] above, the flow channel may have an inlet and an outlet. The inlet is located at the upstream end in the direction of passage of the fluid. The outlet is located at the downstream end in the direction of passage of the fluid. When the inlet of the flow channel is taken as 0% and the outlet of the flow channel is taken as 100%, the flow diversion section may be arranged in a range of 1% to 100% of the flow channel.

[0007] According to an embodiment of the present invention, a membrane reactor that can improve the production efficiency of a target compound can be realized.

[0008] FIG. 1 is a schematic diagram of a membrane reactor according to one embodiment of the present invention. FIG. 2 is a perspective view of a static mixer provided in the membrane reactor of FIG. 1. FIG. 3 is a schematic diagram of a membrane reactor according to another embodiment of the present invention. FIG. 4 is a schematic diagram of a membrane reactor according to yet another embodiment of the present invention. FIG. 5 is a schematic diagram of a membrane reactor according to yet another embodiment of the present invention. FIG. 6 is a perspective view of a flow transformer tube provided in the membrane reactor of FIG. 3. FIG. 7 is a front view of the flow transformer tube of FIG. 6. FIG. 8 is a VIII-VIII' cross-sectional view of the flow transformer tube of FIG. 7. FIG. 9 is a schematic cross-sectional view illustrating an embodiment in which a catalyst layer is provided on the inner surface of the first tube passage of FIG. 8. FIG. 10 is an XX' cross-sectional view of the flow transformer tube of FIG. 7. FIG. 11 is a schematic cross-sectional view illustrating an embodiment in which a catalyst layer is provided on the inner surface of the second tube passage of FIG. 10. FIG. 12 is a schematic cross-sectional view of a membrane reactor according to yet another embodiment of the present invention. FIG. 13 is a schematic cross-sectional view of a membrane reactor according to yet another embodiment of the present invention.

[0009] Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to these embodiments. In addition, in order to clarify the description, the drawings may show the width, thickness, shape, etc. of each part more schematically than in the embodiment, but these are merely examples and do not limit the interpretation of the present invention.

[0010] A. Overview of Membrane Reactor FIG. 1 is a schematic diagram of a membrane reactor according to one embodiment of the present invention. The illustrated membrane reactor 100 has a flow path 10. A fluid can pass through the flow path 10. The membrane reactor 100 includes a catalyst 1, a separation membrane 2, and a flow-diverting section 3. The catalyst 1 is arranged so as to be in contact with the fluid passing through the flow path 10. The catalyst 1 can promote a conversion reaction of the raw material components contained in the fluid. The separation membrane 2 is permeable to reaction products produced by the conversion reaction of the raw material components. The flow-diverting section 3 is arranged in at least a portion of the flow path 10. The flow-diverting section 3 diverts a portion of the flow of the fluid passing through the flow path 10 toward the separation membrane 2. The inventors discovered that in conventional membrane reactors, reaction products entrained in a fluid passing through the central portion of the flow path do not sufficiently reach the separation membrane due to the influence of the catalyst arranged in the flow path and / or the flow velocity (volumetric flow rate) of the fluid. Therefore, after extensive research into the flow of fluid within a flow channel, we discovered that by providing a flow-diverting section in at least a portion of the flow channel, it is possible to efficiently ensure the internal volume and flow rate of the fluid within the flow channel while allowing the reaction products entrained in the fluid to reach the separation membrane. More specifically, the flow-diverting section redirects a portion of the fluid flow passing through the flow channel toward the separation membrane, so that the reaction products (target compound or other compounds) that reach the separation membrane are smoothly removed from the flow channel. As a result, the equilibrium shift effect can further promote the conversion reaction of the raw material components, significantly improving the production efficiency of the target compound.

[0011] A gaseous fluid containing raw material components is typically supplied to the flow path 10. In one embodiment, the gaseous fluid supplied to the flow path 10 contains carbon oxides and hydrogen as raw material components. In this embodiment, the membrane reactor 100 is capable of carrying out a carbon oxide conversion reaction to produce a target compound.

[0012] Examples of carbon oxides include carbon dioxide (CO ２ The raw material gas may contain a single carbon oxide or two or more kinds of carbon oxides. Among the carbon oxides, carbon dioxide (CO ２The respective content ratios of carbon oxides and hydrogen in the gas stream are arbitrarily and appropriately adjusted depending on the conversion reaction carried out in the membrane reactor 100.

[0013] Examples of target compounds that can be produced by the membrane reactor 100 include alcohols such as methanol and ethanol, hydrocarbons such as methane, and mixtures thereof, with alcohols being preferred, and methanol being more preferred. When the membrane reactor 100 is capable of producing methanol, a methanol synthesis reaction is carried out as a carbon oxide conversion reaction, which may include the reactions of the following formulas (1) to (3). In this methanol synthesis reaction, methanol as the target product and water, which is not the target compound, are produced. The reactions of the above formulas (1) to (3) are all equilibrium reactions. Therefore, the reaction product, methanol (CH ３ OH) or water (H ２ When carbon dioxide (CO) is removed from the flow path, the conversion reaction of carbon oxides is promoted due to an equilibrium shift effect, and the yield of methanol as the target compound can be improved.

[0014] The catalyst 1 is arbitrarily and appropriately selected depending on the conversion reaction to be carried out in the membrane reactor 100. Examples of the catalyst 1 include metal catalysts (copper, palladium, nickel, ruthenium, rhodium, platinum, etc.), oxide catalysts (zinc oxide, zirconia, gallium oxide, ceria, etc.), and catalysts made by combining these (copper-zinc oxide, copper-zinc oxide-alumina, copper-zinc oxide-chromium oxide-alumina, copper-cobalt-titania, nickel-ceria, nickel-alumina, ruthenium-ceria, and catalysts obtained by modifying these with palladium, etc.). The catalyst 1 may be used alone or in combination.

[0015] The catalyst 1 is disposed in any suitable manner so as to be in contact with the fluid passing through the flow channel 10. As will be described in detail later, the catalyst 1 may be filled in the flow channel 10, may be contained in the flow deflector 3, or may be contained in a catalyst layer 12 (see FIGS. 2 and 5 ) provided on the surface of the flow deflector 3 and / or the separation membrane 2.

[0016] The separation membrane 2 is capable of separating the target compound, non-target products, and the raw material components produced by the conversion reaction of the raw material components. The separation membrane 2 is impermeable to the raw material components, and relatively permeable to either the target compound or the non-target products produced by the conversion reaction of the raw material components, but relatively impermeable to the other. In one embodiment, the separation membrane 2 is relatively permeable to non-target products in a gaseous state and relatively impermeable to the target compound in a gaseous state. This configuration allows the non-target products to be smoothly removed from the flow path while the reaction of the raw material components proceeds. This can promote the conversion reaction of the raw material components. Meanwhile, permeation of the target compound through the separation membrane can be suppressed, allowing the target compound to remain sufficiently in the flow path. Therefore, the target compound can be efficiently recovered from the flow path.

[0017] The separation membrane 2 has any appropriate configuration depending on the target compound and non-target products. When water is produced in the conversion reaction, a water vapor separation membrane is used as the separation membrane 2. When the separation membrane is a water vapor separation membrane, the water vapor produced in the conversion reaction can be smoothly removed from the flow path. Examples of the water vapor separation membrane include inorganic membranes. Examples of the inorganic membrane include zeolite membranes, silica membranes, alumina membranes, and composite membranes thereof. Among the inorganic membranes, a zeolite membrane is preferred, and an LTA-type zeolite membrane having a molar ratio (Si / Al) of silicon element (Si) to aluminum element (Al) of 1.0 or more and 3.0 or less is more preferred.

[0018] In one embodiment, the separation membrane 2 is supported on a support substrate 6. In other words, the membrane reactor 100 further includes the support substrate 6. The separation membrane 2 and the support substrate 6 constitute a separation membrane composite.

[0019] The support substrate 6 is typically a porous substrate. The support substrate 6 has a skeleton that is continuous in the form of a three-dimensional network and continuous pores defined by the skeleton. The support substrate 6 may be composed of a single layer, or may have a multilayer structure in which multiple layers are stacked. The support substrate 6 preferably has a multilayer structure having multiple layers with different pore diameters. In this case, the closer to the separation membrane 2, the smaller the pore diameter is preferably. The average pore diameter of the support substrate 6 is, for example, 0.01 μm to 70 μm, preferably 0.05 μm to 25 μm. The average pore diameter of the porous substrate on the separation membrane side is 0.01 μm to 1 μm, preferably 0.05 μm to 0.5 μm. The average pore diameter of the porous substrate can be measured, for example, by a mercury porosimeter, a perm porometer, or a nanoperm porometer.

[0020] The support substrate 6 may be made of any appropriate material. A typical example of the material for the support substrate is a ceramic sintered body. Examples of the ceramic sintered body include alumina, silica, mullite, zirconia, titania, yttria, silicon nitride, silicon carbide, and cordierite. The ceramic sintered body may be used alone or in combination. Of the ceramic sintered bodies, alumina is preferred.

[0021] The support substrate 6 may have any appropriate shape. Examples of the shape of the support substrate 6 include a cylindrical shape, a honeycomb shape, and a flat plate shape. In the illustrated example, the support substrate 6 is a cylindrical substrate 61. The cylindrical substrate 61 may extend linearly or may be curved. In the illustrated example, the cylindrical substrate 61 extends linearly. Examples of the cross-sectional shape of the cylindrical substrate 61 cut in a direction perpendicular to the longitudinal direction include a triangle, a rectangle, a pentagon, a polygon with hexagons or more, a circle, and an ellipse, and a circle is preferred.

[0022] In one embodiment, the separation membrane 2 is provided on the inner surface of the cylindrical substrate 61. The separation membrane 2 may be formed on the entire inner surface of the cylindrical substrate 61, or may be formed on a part of the inner surface of the cylindrical substrate 61. The internal space of the cylindrical substrate 61 (the space defined by the inner circumferential surface of the cylindrical substrate) includes a flow path 10. In the illustrated example, the separation membrane 2 is provided on the entire inner surface of the cylindrical substrate 61, and has a cylindrical shape extending in the direction in which the fluid passes. This defines the internal space of the separation membrane 2 as the flow path 10. In this embodiment, the separation membrane 2 faces the flow path 10.

[0023] The flow channel 10 has an inlet 10a and an outlet 10b. The inlet 10a is located at the upstream end of the flow channel 10 in the direction of fluid passage. The outlet 10b is located at the downstream end of the flow channel 10 in the direction of fluid passage. A fluid (typically a gas fluid) containing the above-mentioned raw material components flows into the inlet 10a. A fluid (typically a gas fluid containing the target compound) is discharged from the outlet 10b.

[0024] The flow channel 10 may extend linearly or curvedly. In the illustrated example, the flow channel 10 extends linearly. The cross-sectional shape of the flow channel 10 cut in a direction perpendicular to the central axis direction may be, for example, the same as the cross-sectional shape of the cylindrical substrate 61 described above. The central axis direction of the flow channel 10 is defined by continuously connecting the centers of the cross sections of the flow channel 10 cut in the perpendicular direction from the inlet 10a to the outlet 10b. The central axis direction of the flow channel 10 is substantially parallel to the direction in which the fluid passes. The cross-sectional area of ​​the flow channel 10 cut in a direction perpendicular to the central axis direction (hereinafter referred to as the cross-sectional area of ​​the flow channel 10) can be adjusted arbitrarily and appropriately. The cross-sectional area of ​​the flow channel 10 is, for example, 0.5 mm ２ ~10,000 mm ２ and preferably 1.0 mm ２ ~1000mm ２The total length L of the flow channel 10 can be adjusted arbitrarily and appropriately. The total length L of the flow channel 10 is, for example, 10 mm to 5000 mm, and preferably 100 mm to 2000 mm. When the cross-sectional area and / or the total length of the flow channel are within such ranges, the catalyst can be sufficiently disposed in the flow channel, thereby improving the performance of the membrane reactor.

[0025] The current transformer 3 is disposed at any appropriate position within the flow channel 10. When the total length L of the flow channel 10 is taken as 100%, the proportion of the region L1 where the current transformer 3 is disposed is, for example, 1% or more, preferably 10% or more, and more preferably 25% or more. When the current transformer is disposed in the flow channel at such a proportion, the reaction product generated within the flow channel can be stably guided to reach the separation membrane, thereby further improving the production efficiency of the target compound. On the other hand, the upper limit of the proportion of the region L1 where the current transformer 3 is disposed is typically 100%.

[0026] In one embodiment, the flow diversion section 3 is disposed in a range of 1% to 100% of the flow channel 10, where the inlet 10a of the flow channel 10 is defined as 0% and the outlet 10b of the flow channel 10 is defined as 100%. The flow diversion section 3 is preferably disposed in a range of 10% to 100% of the flow channel 10. When the flow diversion section is disposed in such a range of the flow channel, the reaction products generated in the flow channel can be more stably allowed to reach the separation membrane, thereby further improving the production efficiency of the target compound.

[0027] The number of flow diversion sections 3 arranged in the flow path 10 is not particularly limited. As shown in FIG. 1 , one flow diversion section 3 may be arranged in the flow path 10, or as shown in FIG. 3 , multiple flow diversion sections 3 may be arranged in the flow path 10. The multiple flow diversion sections 3 are arranged spaced apart from one another in the central axis direction of the flow path 10. The sum of the dimensions L2 of the multiple flow diversion sections 3 in the central axis direction of the flow path 10 (the direction in which the flow path 10 extends) is, for example, 1% or more, preferably 25% or more, of the total length of the flow path 10 (100%). On the other hand, the sum of the dimensions L2 of the multiple flow diversion sections 3 in the central axis direction of the flow path 10 is, for example, 99% or less, preferably 90% or less, of the total length of the flow path 10 (100%). When the ratio of the sum of the dimensions of the multiple flow diversion sections to the total length of the flow path is within this range, both the catalyst loading amount and the flow diversion effect can be achieved.

[0028] As shown in Figure 1, such a flow deflection section 3 typically has a guide surface 31. The guide surface 31 extends at various points within the flow channel 10 in a direction intersecting the central axis direction of the flow channel 10. The guide surface 31 may be perpendicular to the central axis direction, or may intersect the central axis direction without being perpendicular to the central axis direction. When the flow deflection section has such a guide surface, the guide surface guides the fluid passing through the flow channel, and can stably divert part of the fluid flow toward the separation membrane.

[0029] B. Membrane Reactor with Static Mixer As shown in Figure 2, in one embodiment, the flow diversion section 3 is a static mixer 4. When the flow diversion section is a static mixer, the fluid passing through the flow path can be agitated, and the reaction product can reach the separation membrane more stably.

[0030] The static mixer 4 may have any appropriate shape and configuration. The static mixer 4 typically includes a first element 41 and a second element 42 that are integrally formed. The first elements 41 and the second elements 42 are alternately arranged in the longitudinal direction of the static mixer 4 and are connected to each other. The static mixer 4 is arranged in the flow path 10 so that the axis of the static mixer 4 is substantially parallel to the central axis of the flow path 10 (see FIG. 1 ).

[0031] Each of the first element 41 and the second element 42 has a structure in which a plate having a predetermined thickness is twisted around the axis of the static mixer 4. The first element 41 and the second element 42 are twisted in opposite directions to each other.

[0032] The surfaces of the first element 41 and the second element 42 function as the guide surface 31 described above. The dimensions (lengths) of the first element 41 and the second element 42 in the central axis direction of the flow channel 10 can be changed arbitrarily and appropriately. By changing the lengths of the first element 41 and the second element 42, the angle of the guide surface with respect to the central axis direction of the flow channel can be adjusted appropriately. As shown in FIG. 4 , by shortening the length of the first element 41 and / or the second element 42, the inclination of the guide surface 31 with respect to the central axis direction of the flow channel 10 can be increased. The outer diameters of the first element 41 and the second element 42 can be changed arbitrarily and appropriately.

[0033] 1, in one embodiment, the catalyst 1 is packed in a flow path 10 in which a static mixer 4 is disposed. In the illustrated example, catalyst pellets 11 containing the catalyst 1 are packed in the flow path 10. The average maximum length of the plurality of catalyst pellets 11 is, for example, 0.1 mm to 10 mm.

[0034] The catalyst pellets 11 may be composed of only the catalyst 1, or may contain other components in addition to the catalyst 1. Examples of other components include an inert substance such as alumina. When the catalyst pellets contain an inert substance, the operating temperature of the membrane reactor can be appropriately controlled. The content of the catalyst 1 in the catalyst pellets 11 is, for example, 10% by mass to 100% by mass, and preferably 50% by mass to 100% by mass.

[0035] The catalyst pellets 11 may be porous. The average pore diameter of the catalyst pellets 11 is, for example, 1 nm to 100 μm, and preferably 1 nm to 1 μm. The BET specific surface area of ​​the catalyst pellets 11 is, for example, 10 m ２ / g to 2000m ２ / g, preferably 500m ２ / g to 2000m ２ / g.

[0036] Furthermore, in addition to the catalyst pellets 11, inert particles made of an inert material may be filled in the flow channels 10. This also makes it possible to appropriately control the operating temperature of the membrane reactor.

[0037] 2, the catalyst 1 may be contained in a catalyst layer 12 provided on a guide surface 31 of a static mixer 4. The thickness of the catalyst layer 12 is, for example, 100 μm to 10 mm, and preferably 100 μm to 1 mm.

[0038] The catalyst layer 12 typically contains an aggregate of a plurality of catalyst particles. The aggregate of a plurality of catalyst particles can form mesopores in the catalyst layer 12. The catalyst layer 12 may be composed of only catalyst 1, or may contain other components in addition to catalyst 1. Examples of other components include an inert substance such as alumina. When the catalyst layer contains an inert substance, the operating temperature of the membrane reactor can be appropriately controlled. The content of catalyst 1 in the catalyst layer 12 is, for example, 10% by mass to 100% by mass, and preferably 50% by mass to 100% by mass. The catalyst loading in the catalyst layer 12 is, for example, 0.01 mg / mm ２ ~100 mg / mm ２ and preferably 0.2 mg / mm ２ ~50 mg / mm ２ is.

[0039] The average pore diameter of the catalyst layer 12 is, for example, 1 nm to 100 μm, and preferably 1 nm to 1 μm. The BET specific surface area of ​​the catalyst layer 12 is, for example, 10 m ２ / g to 2000m ２ / g, preferably 500m ２ / g to 2000m ２ / g.

[0040] 5 , the catalyst layer 12 may be provided on the surface of the separation membrane 2. In one embodiment, the catalyst layer 12 is provided on the surface of the separation membrane 2 opposite the support substrate 6. The catalyst layer 12 may be formed on the entire surface of the separation membrane 2 opposite the support substrate 6, or may be formed on a part of that surface. In the illustrated example, the catalyst layer 12 is provided on the entire surface of the separation membrane 2 opposite the support substrate 6, and has a cylindrical shape extending in the direction of fluid passage. As a result, in this embodiment, the internal space of the catalyst layer 12 is defined as a flow path 10, and the catalyst layer 12 faces the flow path 10.

[0041] Furthermore, the catalyst 1 may be contained in the static mixer 4. In this case, the static mixer 4 is made of a material containing the catalyst 1. The content of the catalyst 1 in the static mixer 4 is, for example, 0% by mass to 100% by mass, and preferably 50% by mass to 100% by mass.

[0042] C. Membrane Reactor with Flow Transformer Tube As shown in Figures 6 and 7, in one embodiment, the flow transformer section 3 is a flow transformer tube 5. The flow transformer tube 5 has any appropriate outer shape depending on the shape of the flow path 10. The flow transformer tube 5 has a columnar shape extending in the central axis direction of the flow path 10. In the illustrated example, the flow transformer tube 5 has a substantially cylindrical shape.

[0043] As shown in Figure 8, the flow transformer tube 5 has a first tube passage 51. A fluid can pass through the first tube passage 51. The first tube passage 51 typically penetrates the flow transformer tube 5 in the central axial direction of the flow path 10. The first tube passage 51 is inclined so as to approach the separation membrane 2 toward the downstream side in the fluid passage direction. The inner surface of the first tube passage 51 functions as the guide surface 31. When the flow transformer section is a flow transformer tube having a first tube passage, the fluid entrained with the reaction product can be stably guided to the vicinity of the separation membrane.

[0044] The first pipe passage 51 may extend linearly or may be curved. In the illustrated example, the first pipe passage 51 is curved. The upstream end of the first pipe passage 51 in the fluid passage direction is positioned so as to overlap with the central axis of the flow channel 10. The downstream end of the first pipe passage 51 in the fluid passage direction is positioned closer to the separation membrane 2 than the central axis of the flow channel 10. With this configuration, the fluid passing near the central axis of the flow channel can be stably guided to the vicinity of the separation membrane.

[0045] In one embodiment, the flow transformer tube 5 has a plurality of first tube passages 51. The upstream ends of the plurality of first tube passages 51 are connected to one another. The downstream ends of the plurality of first tube passages 51 are spaced apart from one another in the circumferential direction of the flow transformer tube 5. With this configuration, the fluid passing near the central axis of the flow path can be dispersed in the circumferential direction of the flow transformer tube and guided to the vicinity of the separation membrane. The number of first tube passages 51 is not particularly limited. The number of first tube passages 51 is, for example, 1 to 12, and preferably 4 to 8.

[0046] In one embodiment, the catalyst 1 is filled in the first pipe passage 51. In the illustrated example, the above-described catalyst pellets 11 are filled in the first pipe passage 51. Also, as shown in Fig. 9, the above-described catalyst layer 12 may be provided on the inner surface of the first pipe passage 51 (i.e., the guide surface 31).

[0047] As shown in FIG. 10 , in one embodiment, the flow transformer tube 5 further includes a second tube passage 52. The second tube passage 52 allows fluid to pass through. The second tube passage 52 typically penetrates the flow transformer tube 5 in the direction of the central axis of the flow path 10. The second tube passage 52 is inclined so as to approach the central axis of the flow path 10 toward the downstream side in the direction of fluid passage. When the flow transformer tube includes the first tube passage and the second tube passage, fluid passing near the central axis of the flow path can be smoothly replaced with fluid passing near the separation membrane. Therefore, the concentration of the substance to be removed (typically, a product other than the target compound) in the flow path can be sufficiently reduced while ensuring a smooth flow of fluid in the flow path.

[0048] The second pipe passage 52 may extend linearly or may be curved. In the illustrated example, the second pipe passage 52 is curved. The upstream end of the second pipe passage 52 in the fluid passage direction is located closer to the separation membrane 2 than the central axis of the flow channel 10. The downstream end of the second pipe passage 52 in the fluid passage direction is located so as to overlap with the central axis of the flow channel 10. This configuration allows for smooth fluid replacement.

[0049] In one embodiment, the flow transformer tube 5 has a plurality of second tube passages 52. The upstream ends of the plurality of second tube passages 52 are arranged at intervals in the circumferential direction of the flow transformer tube 5. The downstream ends of the plurality of second tube passages 52 are in communication with each other. With this configuration, fluid passing near the separation membrane can be collected and guided to the vicinity of the central axis of the flow path. The number of second tube passages 52 is not particularly limited. The number of second tube passages 52 is, for example, 1 to 12, and preferably 4 to 8.

[0050] In the illustrated example, the current transformer tube 5 has a plurality of first tube passages 51 and a plurality of second tube passages 52 (see FIG. 7 ). In this case, the number of first tube passages 51 is preferably the same as the number of second tube passages 52. Each of the plurality of second tube passages 52 is disposed between adjacent first tube passages 51 in the circumferential direction of the current transformer tube 5.

[0051] In one embodiment, the catalyst 1 is filled in the second pipe passage 52. In the illustrated example, the above-described catalyst pellets 11 are filled in the second pipe passage 52. Alternatively, as shown in FIG. 11 , the above-described catalyst layer 12 may be provided on the inner surface of the second pipe passage 52.

[0052] Furthermore, the catalyst 1 may be contained in the current transformer tube 5. In this case, the current transformer tube 5 is made of a material containing the catalyst 1. The range of the content ratio of the catalyst 1 in the current transformer tube 5 is, for example, the same as the range of the content ratio of the catalyst 1 in the static mixer 4 described above.

[0053] As shown in FIG. 12 , in one embodiment, catalyst 1 (catalyst pellets or a catalyst layer) is provided in the first tube passage 51 of the flow transformer tube 5, and catalyst 1 (catalyst pellets or a catalyst layer) is not provided in the second tube passage 52 of the flow transformer tube 5. The temperature of the first space (passage) on the non-permeation side where the reaction occurs is maintained at a predetermined temperature by controlling the temperature of the second space on the permeation side. However, for example, if the reaction is exothermic, regions higher and lower than the predetermined temperature may occur in the first space. Such temperature non-uniformity is generally undesirable, and if the temperature non-uniformity is extremely large, these regions are called hot spots and cold spots and may adversely affect the performance of the membrane reactor. In this embodiment, the reaction heat generated in the first tube passage of the flow transformer tube is adjusted to an appropriate temperature on the wall surface and then removed by the fluid flowing through the second tube passage without reacting. In other words, the heat exchange action of the flow transformer tube, which has a first tube passage with a catalyst and a second tube passage without a catalyst, can appropriately control the reaction temperature in the first tube passage so that it does not rise too high. Furthermore, since the second tube passage contains a catalyst, it is undesirable for water vapor generated by the reaction in the tube to flow into the inner region, which is far from the separation membrane and where it is difficult to discharge water vapor. This configuration can prevent this.

[0054] A plurality of such current transformer tubes 5 are typically arranged at intervals from one another in the central axial direction of the flow path 10 (see FIG. 3 ). The catalyst 1 (more specifically, catalyst pellets 11) may be filled between adjacent ones of the plurality of current transformer tubes 5, or the catalyst 1 may not be filled therebetween.

[0055] As shown in FIG. 13 , the membrane reactor 100 may further include a tubular member 7. The tubular member 7 is disposed within the flow path 10 between adjacent ones of the plurality of flow transformer tubes 5. The tubular member 7 typically has a tubular shape extending in the direction of the central axis of the flow path 10. The tubular member 7 typically has a substantially cylindrical shape. The tubular member 7 divides the flow path 10 into an inner region including the central axis of the flow path 10 and an outer region in which the separation membrane 2 is located. This configuration can prevent remixing of the fluid that flows through the inner region of the flow path after passing through the flow transformer tube and the fluid that flows through the outer region. The purpose of fluid replacement is to transport a gas fluid with a high water vapor concentration to the outer region and to transport the gas fluid with a lower water vapor concentration by allowing the water vapor to permeate the membrane to the inner region. Therefore, when the fluid flowing through the inner region and the fluid flowing through the outer region are remixed, the water vapor sent to the outside is divided into a portion that permeates the membrane and a portion that returns to the inside by diffusion, which may reduce the water vapor permeation efficiency. In this regard, according to this embodiment, water vapor can be sufficiently concentrated near the membrane, and the water vapor permeation rate can be improved.

[0056] The inner region is defined by the inner surface of the tubular member 7. In one embodiment, the upstream end of the first tube passage 51 of the current transformer tube 5 and the downstream end of the second tube passage 52 of the current transformer tube 5 each communicate with the inner region.

[0057] The outer region is located radially outward of the cylindrical member 7. The outer region is defined by the outer surface of the cylindrical member 7 and the inner surface of the support substrate 6. In one embodiment, the downstream end of the first tube passage 51 of the current transformer tube 5 and the upstream end of the second tube passage 52 of the current transformer tube 5 each communicate with the outer region. Each of the inner region and the outer region may be filled with catalyst 1 (more specifically, catalyst pellets 11), or may not be filled with catalyst 1. The inner region and the outer region are preferably filled with catalyst pellets 11.

[0058] D. Methanol Production Method Next, with reference to FIG. 1 , one embodiment of a methanol production method using a membrane reactor 100 will be described. The following description will be focused on a case where the separation membrane 2 is a water vapor separation membrane and water, a product other than the target compound, is removed from the flow path 10. To produce methanol in the membrane reactor 100, the membrane reactor 100 is heated to a predetermined reaction initiation temperature, and a feed gas (gas fluid) containing carbon oxides and hydrogen is supplied to the inlet 10a of the flow path 10. The reaction initiation temperature is, for example, 120°C to 300°C. The pressure in the flow path 10 is, for example, 0.5 MPa to 10 MPa. Any appropriate value can be adopted as the volumetric flow rate of the feed gas. The volumetric flow rate of the feed gas is, for example, 0.001 NL / min to 20 NL / min.

[0059] Next, when carbon oxides and hydrogen contained in the raw material gas come into contact with the catalyst 1 in the flow channel 10, the methanol synthesis reaction represented by the above formulas (1) to (3) can proceed. This produces methanol (the target compound) and water (a product other than the target compound). The produced methanol and water travel in a gaseous state, entrained in the gaseous fluid. Because water vapor contained in the gaseous fluid flowing near the separation membrane 2 easily reaches and permeates the separation membrane 2, the water vapor concentration of the gaseous fluid flowing over a long distance near the separation membrane 2 tends to decrease the longer the distance. Furthermore, the rate at which water vapor permeates the separation membrane 2 decreases as the water vapor concentration decreases, so the rate at which water vapor is discharged from the gaseous fluid also tends to decrease. On the other hand, the water vapor contained in the gaseous fluid flowing in the inner region around the central axis of the flow channel 10 tends to have a higher concentration than in the outer region because it travels a longer distance to the separation membrane 2. When the gaseous fluid reaches the flow diversion section 3, the flow diversion section 3 redirects part of the gaseous fluid flow, i.e., the flow of the gaseous fluid in the inner region with a higher water vapor concentration, toward the separation membrane 2. As a result, more water vapor reaches the separation membrane 2 and permeates through it. Furthermore, the higher the water vapor concentration, the faster the water vapor permeates through the separation membrane 2, and therefore the rate at which water vapor is discharged from the gaseous fluid also tends to increase. As a result, more water vapor is removed from the flow path 10, accelerating the above-described methanol synthesis reaction. Meanwhile, the gaseous fluid with a reduced water vapor concentration that did not permeate the separation membrane 2 can flow back from the separation membrane 2 toward the central axis of the flow path 10.

[0060] As a result, the methanol synthesis reaction proceeds smoothly in the membrane reactor 100, and a methanol-containing gas is continuously discharged from the outlet 10b of the flow path 10. The methanol-containing gas contains at least methanol. The methanol-containing gas may contain the raw material gas that remains unreacted, or may contain water vapor as a product that is not the target compound. In such a membrane reactor 100, methanol can be produced with an excellent conversion rate. ２ Alternatively, the CO conversion rate is, for example, 40% or more, preferably 45% or more, and more preferably 50% or more. ２ Alternatively, the CO conversion is, for example, 100% or less, or, for example, 90% or less.

[0061] The membrane reactor according to the embodiment of the present invention can be used to produce various target compounds, and can be particularly suitably used to produce methanol.

[0062] REFERENCE SIGNS LIST 1 catalyst 2 separation membrane 3 flow transformer 4 static mixer 5 flow transformer tube 51 first tube passage 52 second tube passage 100 membrane reactor

Claims

1. A membrane reactor having a flow path through which a fluid can pass, comprising: a catalyst arranged to be in contact with the fluid passing through the flow path and promoting a conversion reaction of raw material components contained in the fluid; a separation membrane permeable to reaction products produced by the conversion reaction of the raw material components; and a flow-diverting section arranged in at least a part of the flow path and diverting a part of the flow of the fluid passing through the flow path so that it flows toward the separation membrane.

2. The membrane reactor according to claim 1, wherein the catalyst is packed in the channels.

3. The membrane reactor according to claim 1, wherein the flow transformer section includes the catalyst.

4. The membrane reactor according to claim 1, further comprising: a support substrate supporting the separation membrane; and a catalyst layer containing the catalyst, the catalyst layer being provided on the surface of the separation membrane opposite to the support substrate.

5. The membrane reactor described in claim 1, wherein the flow-changing section has, at each location within the flow path, a guide surface extending in a direction intersecting a central axis direction that continuously connects the centers of cross sections cut perpendicular to the flow path from the upstream end to the downstream end of the flow path.

6. The membrane reactor according to claim 5, wherein the guide surface is provided with a catalyst layer containing the catalyst.

7. The membrane reactor according to claim 1, wherein the flow transformer is a static mixer.

8. The membrane reactor according to claim 1, wherein the flow-changing section has a first pipe passage through which the fluid can pass, and the first pipe passage is inclined so as to approach the separation membrane as it moves downstream in the direction of passage of the fluid.

9. The membrane reactor according to claim 8, wherein the catalyst is packed in the first tube passage.

10. The membrane reactor according to claim 8, wherein the inner surface of the first tube passage is provided with a catalyst layer containing the catalyst.

11. The membrane reactor according to claim 8, wherein the flow-changing section has a second pipe passage through which the fluid can pass, and the second pipe passage is inclined so as to approach the central axis of the flow path as it moves downstream in the direction of passage of the fluid.

12. The membrane reactor according to claim 11, wherein the catalyst is packed in the second tube passage.

13. The membrane reactor according to claim 11, wherein the inner surface of the second tube passage is provided with a catalyst layer containing the catalyst.

14. The membrane reactor according to claim 11, further comprising: a plurality of the flow-diverting sections arranged at intervals in a central axial direction that continuously connects the centers of cross sections obtained by cutting the flow channel in a direction perpendicular to the flow channel from the upstream end to the downstream end of the fluid; and a tubular member that is arranged between adjacent flow-diverting sections among the plurality of flow-diverting sections, wherein the tubular member divides the flow channel into an inner region that includes the central axis of the flow channel and an outer region in which the separation membrane is located.

15. A membrane reactor according to any one of claims 1 to 14, wherein the ratio of the area in which the flow-diverting section is arranged to the total length of the flow path is 100% is 1% or more.

16. The membrane reactor according to claim 15, comprising a plurality of the flow-diverting sections arranged at intervals from one another in a central axial direction that continuously connects the centers of cross sections obtained by cutting the flow path in a direction perpendicular to the flow path from the upstream end to the downstream end of the fluid, and the sum of the dimensions of the plurality of flow-diverting sections in the direction in which the flow path extends is 1% or more and 99% or less of the total length of the flow path (100%).

17. A membrane reactor according to any one of claims 1 to 14, wherein the flow path has an inlet located at the upstream end in the direction of passage of the fluid and an outlet located at the downstream end in the direction of passage of the fluid, and when the inlet of the flow path is taken as 0% and the outlet of the flow path is taken as 100%, the flow transformer is disposed in a range of 1% to 100% of the flow path.

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