Membrane reactor and membrane reaction method

Abstract

To provide a membrane reactor having a pre-reaction region and capable of stably supporting a separation membrane, and a membrane reaction method.SOLUTION: A membrane reactor 1 according to the present invention includes a membrane reactor body 11 having a reaction zone 14 for reacting a raw material, the reaction zone 14 being filled with a catalyst to form a catalyst packed bed, a raw material supply port 15 for supplying the raw material to the reaction zone 14, and a product discharge port 16 for discharging a reaction product from the reaction zone; The membrane reactor includes one or more separation membranes 12 for separating a by-product produced together with a reaction product by reaction of a raw material, and one or more membrane support bodies 13 for supporting the one or more separation membranes 12, wherein the membrane support bodies 13 are supported at both ends by a membrane reactor body 11, and a reaction region 14 is continuously reduced from a raw material supply port 15 toward a product discharge port 16.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a membrane reactor and a membrane reaction method, and more particularly to a membrane reactor and a membrane reaction method for carrying out a reaction with high efficiency while separating and removing by-products using a separation membrane. [Background technology]

[0002] In recent years, membrane reactors have been developed that are capable of carrying out chemical reactions with high efficiency by providing a separation membrane in a reactor to separate and remove by-products other than the target reaction product from the reaction system. For example, Patent Document 1 discloses a membrane reactor that can produce useful chemical products such as methanol with high efficiency from carbon dioxide (hereinafter also referred to as "CO2") emitted from processes such as steelmaking.

[0003] Methanol can be synthesized by the reaction shown in reaction formula (1) below, which uses carbon monoxide (CO) and hydrogen (H2) as raw materials, or by the reaction shown in reaction formula (2), which uses CO2 and H2 as raw materials. In reaction formula (2), which produces water (H2O) as a by-product, the equilibrium conversion rate from CO2 to methanol is low, resulting in a significant increase in the amount of unreacted gas circulated to the inlet side of the membrane reactor, significantly reducing methanol production efficiency. Therefore, by selectively removing H2O, the by-product of reaction formula (2), through a separation membrane, the equilibrium in reaction formula (2) shifts toward the product side based on Le Châtelier's principle, significantly improving methanol production efficiency. CO + 2H → CHOH (1) CO2 + 3H2 → CH3OH + H2O (2)

[0004] As described in Patent Documents 2 and 3, membrane reactors are generally designed with a structure in which a catalyst packed bed having a separation membrane is provided with a raw material supply port and a product discharge port. Separation membranes used are either flat, with a perforated plate as the membrane support and a separation membrane formed on the surface thereof, or tubular, with a perforated tube as the membrane support and a separation membrane formed on the surface thereof (hereinafter also referred to as "tubular membranes"). When scaling up a membrane reactor, it is designed with a structure in which multiple such separation membranes are stacked or arranged.

[0005] Examples of support structures for separation membranes include a double-supported support structure as disclosed in Patent Document 3, and a cantilevered support structure in which the separation membrane is self-supporting inside the catalyst packed bed as disclosed in Patent Documents 4 and 5. In the case of a membrane reactor, the separation membrane thermally expands when the temperature is raised to the reaction temperature, so a cantilevered support structure can suppress the generation of thermal stress in the separation membrane in the longitudinal direction due to thermal expansion.

[0006] Separation membranes used in membrane reactors include molecular sieve-type membranes, which utilize the difference in pore size between the membrane and the molecular size of the product, as shown in Figure 1(a), and adsorption-type membranes, which utilize the affinity between the membrane and by-products (e.g., HO), as shown in Figure 1(b). The latter type, adsorption-type membranes, in particular, can use membranes with relatively large pore sizes, which increases the membrane permeation rate of the by-products being separated and can be effectively used in reaction systems with high reaction rates. However, because adsorption-type membranes function on the premise that by-products are adsorbed onto the membrane, if raw materials are supplied to the membrane without reacting, the raw materials themselves will permeate (leak) through the membrane, significantly reducing reaction efficiency.

[0007] As a method for preventing such a phenomenon, Non-Patent Document 1 discloses a membrane reactor provided with a pre-reaction region near the raw material supply port. Figure 2 shows the membrane reactor provided with a pre-reaction region described in Non-Patent Document 1. The membrane reactor 100 shown in Figure 2 includes a membrane reactor body 111, a separation membrane 112 for separating by-products (e.g., HO) produced together with reaction products (e.g., methanol) by the reaction of the raw materials, and a membrane support 113 for supporting the separation membrane 112.

[0008] The membrane reactor main body 111 has a reaction region 114 in which raw materials are reacted, a raw material supply port 115 for supplying raw materials to the reaction region 114, and a product discharge port (not shown) for discharging the reaction product from the reaction region 114. A raw material supply pipe 117 is connected to the raw material supply port 115, and a product discharge pipe (not shown) is connected to the product discharge port (not shown).

[0009] The reaction region 114 has a membrane reaction region 114b, which is a region where the reaction is promoted by the permeation of by-products through the separation membrane 112, and a pre-reaction region 114a, which is a region where a part of the reaction progresses before the raw material reaches the membrane reaction region 114b, and the pre-reaction region 114a is provided near the raw material supply port 115. The reaction region 114 is filled with a catalyst S, and a catalyst packed layer is formed.

[0010] As in the membrane reactor 100 shown in Fig. 2, it is effective to provide a pre-reaction region 114a near the raw material supply port 115. That is, since reaction products (e.g., methanol) and by-products (e.g., HO) are generated as a result of the progress of some of the reactions in the pre-reaction region 114a, the by-products are more likely to be adsorbed onto the separation membrane 112 in the membrane reaction region 114b shown in Fig. 2, and selective separation of the by-products by an adsorption separation method as shown in Fig. 1(b) becomes possible.

[0011] For example, when the by-product HO produced during the methanol synthesis reaction shown in Reaction Scheme (2) above is separated using a hydrophilic LTA zeolite membrane (see Non-Patent Document 2), the pore size of the LTA zeolite membrane is larger than all of the molecules described in Reaction Scheme (2). Therefore, if the LTA zeolite membrane is partially reacted with HO in the pre-reaction zone, the resulting HO is adsorbed onto the LTA zeolite membrane, and then the HO is extracted to the permeation side of the membrane. This effectively blocks the pores due to HO adsorption, suppressing the permeation of CO, H, and other feed gases, thereby enabling selective separation of HO. The size of the membrane reaction zone is determined by the separation rate of the product through the separation membrane and the diffusion rate of the product within the catalyst packed bed near the separation membrane. This can be estimated using CFD analysis or temperature distribution measurements using thermocouples inserted into the catalyst packed bed. [Prior art documents] [Patent documents]

[0012] [Patent Document 1] Japanese Patent Application Laid-Open No. 2018-008940 [Patent Document 2] Special Publication No. 2023-530358 [Patent Document 3] International Publication No. 2012 / 086836 [Patent Document 4] Japanese Patent Application Laid-Open No. 2007-55970 [Patent Document 5] Japanese Patent Application Laid-Open No. 2007-55975 [Non-patent literature]

[0013] [Non-Patent Document 1] Kenji Haratani and Naotsugu Ito: Separation Technology Series 31 Fundamentals and Applications of Gas Separation Membrane Processes, Separation Technology Society (2015) [Non-patent document 2] Seshimo, M., et al.: Membrane Reactor for Methanol Synthesis Using Si-Rich LTA Zeolite Membrane, Membranes 2021, 11, 505 Summary of the Invention [Problem to be solved by the invention]

[0014] On the other hand, when the pre-reaction region 114a as shown in Non-Patent Document 1 is provided, the separation membrane 112 is cantilevered within the catalyst packed bed, and although the packed catalyst provides a certain degree of stability in its support, the separation membrane 112 is more likely to be damaged by vibrations, etc. Therefore, the length of the separation membrane 112 is limited by the cantilever support strength, making it difficult to scale up the membrane reactor 100.

[0015] Furthermore, it is possible to provide a design with a vibration stopper at the tip of the separation membrane if the structure is such that the tip of the separation membrane protrudes outside the catalyst packed bed, as in the membrane reactor described in Patent Document 2. However, in the case of a design such as that described in Non-Patent Document 1, the vibration stopper at the tip of the separation membrane is provided inside the catalyst packed bed, and there is a concern that the influence of the vibration stopper may cause the flow of raw materials and products within the catalyst packed bed to become uneven, preventing the catalyst and separation membrane from fully performing.

[0016] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a membrane reactor and a membrane reaction method which have a pre-reaction region and can stably support a separation membrane. [Means for solving the problem]

[0017] The present invention, which solves the above problems, is as follows. [1] A membrane reactor that reacts raw materials to produce a target reaction product, a membrane reactor body having a reaction region in which the raw materials are reacted, the reaction region being filled with a catalyst to form a catalyst-filled layer, a raw material supply port for supplying the raw materials to the reaction region, and a product discharge port for discharging the reaction product from the reaction region; One or more separation membranes disposed in the reaction region of the membrane reactor body, for separating by-products produced together with the reaction product by the reaction of the raw materials; one or more membrane supports supporting the one or more separation membranes; Equipped with The membrane support is supported at both ends by the membrane reactor body, A membrane reactor characterized in that the reaction zone is continuously narrowed from the raw material supply port toward the product discharge port.

[0018] [2] Further comprising a heat transfer tube for controlling the temperature of the catalyst packed bed, and a heat medium supply device for supplying a heat medium into the heat transfer tube, The membrane reactor according to [1] above, wherein the heat transfer tubes are arranged so that the temperature control capability of the catalyst packed bed increases from the product discharge port toward the raw material supply port.

[0019] [3] The membrane reactor according to [1] or [2], wherein the membrane support has a tubular structure having a sealed end and an open end, the one or more separation membranes are disposed on the outer surface and / or inner surface of the membrane support, and the membrane reactor body has a fixing part for fixing the open end of the membrane support and a supporting part for supporting the sealed end of the membrane support.

[0020] [4] The membrane reactor body comprises a first tube and a second tube housed inside the first tube; the reaction zone is provided between the first pipe and the second pipe, the raw material supply port is provided in one of the first pipe and the second pipe, and the product discharge port is provided in the other pipe; The membrane reactor according to [3] above, wherein the fixing part is provided on one of the first pipe and the second pipe, and the supporting part is provided on the other.

[0021] [5] The membrane reactor according to [3] or [4], wherein a sweep pipe for circulating a sweep fluid for promoting separation of the by-products that have permeated the separation membrane is provided inside the membrane support.

[0022] [6] A membrane reaction method for producing a reaction product by reacting raw materials using the membrane reactor according to any one of [1] to [5] above, a membrane reaction method comprising: supplying the raw materials from the raw material supply port, reacting the raw materials in the reaction region, separating the produced by-products using the separation membrane, and discharging the produced reaction products from the product discharge port.

[0023] [7] The membrane reaction method according to [6], which cites [2], wherein the raw material gas is supplied while the heat transfer medium is circulating through the heat transfer tube.

[0024] [8] The membrane reaction method according to [6] or [7], which refers to [5], wherein the raw material gas is supplied while the sweeping fluid is circulating through the sweeping pipe. [Effects of the Invention]

[0025] According to the present invention, a separation membrane can be stably supported in a membrane reactor having a pre-reaction region. [Brief explanation of the drawings]

[0026] [Figure 1] 1 is a diagram illustrating a molecular sieve type separation membrane and an adsorption type separation membrane. [Figure 2] 1 is a cross-sectional view of a portion of a membrane reactor having a pre-reaction zone. [Figure 3] FIG. 1 is a cross-sectional view of a first example of a membrane reactor according to the present invention. [Figure 4] FIG. 1 shows the structure of a tubular membrane support, a fixing part and a supporting part. [Figure 5] 10A and 10B are diagrams illustrating an example of the installation of a sweep pipe and an example of a method of circulating a sweeping fluid. [Figure 6] FIG. 2 is a cross-sectional view of a second example of a membrane reactor according to the present invention. [Figure 7] FIG. 2 is a cross-sectional view of a third example of a membrane reactor according to the present invention. [Figure 8] FIG. 1 is a cross-sectional view of a fourth example of a membrane reactor according to the present invention. [Figure 9] FIG. 10 is a cross-sectional view of a fifth example of a membrane reactor according to the present invention. [Figure 10] FIG. 10 is a cross-sectional view of a sixth example of a membrane reactor according to the present invention. [Figure 11] 1 is a cross-sectional view in the thickness direction of a membrane reactor according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0027] (Membrane reactor) Hereinafter, an embodiment of the present invention will be described with reference to the drawings. A membrane reactor according to the present invention is a membrane reactor for reacting raw materials to produce a reaction product, and includes a reaction region for reacting the raw materials, the reaction region being filled with a catalyst to form a catalyst-packed layer, a membrane reactor body having a raw material supply port for supplying raw materials to the reaction region and a product discharge port for discharging the reaction product from the reaction region, one or more separation membranes disposed in the reaction region of the membrane reactor body for separating by-products produced together with the reaction product by the reaction of the raw materials, and one or more membrane supports for supporting the one or more separation membranes. Here, the membrane supports are supported at both ends by the membrane reactor body, and the reaction region is characterized in that it continuously narrows from the raw material supply port toward the product discharge port.

[0028] 3 is a cross-sectional view of a first example of a membrane reactor according to the present invention. The membrane reactor 1 shown in FIG. 3 comprises a membrane reactor body 11, a separation membrane 12, and a membrane support 13.

[0029] The membrane reactor main body 11 is a vessel in which raw materials are reacted. The membrane reactor main body 11 has a reaction region 14 in which the raw materials are reacted, a raw material supply port 15 for supplying the raw materials to the reaction region 14, and a product discharge port 16 for discharging the reaction product from the reaction region 14. The reaction region 14 consists of a pre-reaction region 14a and a membrane reaction region 14b. In the membrane reactor 1 shown in Figure 3, a raw material supply pipe 17 is connected to the raw material supply port 15, and a product discharge pipe 18 is connected to the product discharge port 16.

[0030] The internal space (reaction region 14) of the membrane reactor main body 11 is filled with a catalyst that promotes the reaction of the raw materials, and the reaction region 14 forms a catalyst-filled layer.

[0031] The separation membrane 12 is supported by a membrane support 13, and the membrane support 13 is supported on both ends of the membrane reactor body 11.

[0032] In the present invention, it is essential that the reaction region 14 is continuously (monotonically) narrowed from the raw material supply port 15 toward the product discharge port 16. This allows a wider reaction region 14 to be provided near the raw material supply port 15, and makes it possible to provide a pre-reaction region 14a having the same effect as the pre-reaction region 114a in the membrane reactor 100 shown in Fig. 2 near the raw material supply port 15, which has a large catalyst loading, while supporting the membrane support 13, i.e., the separation membrane 12, at both ends.

[0033] In the present invention, the term "membrane reaction region" refers to a region of the reaction region 14 near the separation membrane 12 that does not continuously expand from the product discharge port 16 toward the raw material supply port 15 but is constant (i.e., a region up to a predetermined distance from the surface of the separation membrane 12). For example, when the membrane support 13 is flat, the membrane reaction region 14b is also flat (rectangular) with a constant thickness. When the membrane support 13 is tubular, the membrane reaction region 14b is also tubular with a constant thickness. On the other hand, the term "pre-reaction region" refers to a region of the reaction region 14 other than the membrane reaction region 14b. As described above, in the present invention, the reaction region 14 continuously narrows from the raw material supply port 15 toward the product discharge port 16. Therefore, the pre-reaction region 14a is provided in the reaction region 14 on the raw material supply port 15 side. The pre-reaction region 14a is a region upstream of the membrane reaction region 14b in the flow of the raw material gas from the raw material supply port 15 to the separation membrane 12. By supplying the raw material to the pre-reaction region 14a from the raw material supply port 15, a part of the raw material reacts before reaching the membrane reaction region 14b. Note that the raw material reaction does not necessarily occur in the entire region of the pre-reaction region 14a.

[0034] As described above, the present invention is characterized in that the reaction region 14 is continuously reduced in size from the raw material supply port 15 toward the product discharge port 16, and the membrane support 13 (separation membrane 12) is supported at both ends, and other configurations may be appropriately selected from conventionally known configurations. Each configuration will be specifically described below, but the present invention is not limited to these.

[0035] The shape of the membrane reactor body 11 is not particularly limited as long as the reaction region 14 formed in the internal space of the membrane reactor body 11 continuously narrows from the raw material supply port 15 toward the product discharge port 16, as described above. For example, the membrane reactor body 11 may have a trapezoidal box shape as shown in FIG. 3, a truncated cone shape as shown in FIG. 3, or a cylindrical shape. The shape of the membrane reactor body 11 can be designed taking into consideration its resistance to the reaction pressure. In addition, the reduction ratio can be designed according to the molar flow rate determined from the molar ratio of the raw materials to the product in the reaction formula and the molar ratio of the by-products permeating the separation membrane 12. When the membrane reactor 1 further includes a heat transfer tube, which will be described later, the reduction ratio can be designed taking into consideration the temperature control capability of the heat transfer tube.

[0036] The raw material supply port 15 provided in the membrane reactor main body 11 is preferably positioned so that the raw material is supplied to at least a portion of the pre-reaction region 14a, and so that the raw material is directly supplied to at least a portion of the pre-reaction region 14a. Furthermore, the raw material supply port 15 and the product discharge port 16 are preferably spaced apart appropriately, taking into consideration the diffusivity within the catalyst packed bed to more uniformly distribute and supply the raw material and reaction product toward the separation membrane 12. To facilitate the dispersed supply of the raw material and reaction product to the separation membrane 12, a structure having a plurality of raw material supply ports 15 and product discharge ports 16 is also possible.

[0037] The separation membrane 12 is disposed in the reaction region 14 of the membrane reactor body 11 and separates by-products other than the target reaction product from the reactants produced by the reaction of the raw materials. As shown in FIG. 1(b), the separation membrane 12 is an adsorption separation membrane that separates the products by utilizing the affinity between the separation membrane 12 and the products. As described above, the separation membrane 12 for the adsorption separation method can have a relatively large pore size, which increases the membrane permeation rate of the products to be separated and makes it effective for reaction systems with high reaction rates.

[0038] For example, when methanol is produced from CO2 and H2 in the membrane reactor 1 according to the above reaction formula (2), HO is produced as a by-product in addition to the target methanol. As described above, when methanol is synthesized according to the reaction formula (2), the equilibrium conversion rate from CO2 to methanol is low, and the amount of unreacted gas circulated to the inlet side of the membrane reactor 1 increases significantly, resulting in a significant decrease in methanol production efficiency. Therefore, by selectively removing HO, the by-product of reaction formula (2), through the separation membrane 12, the equilibrium of reaction formula (2) shifts to the production side based on Le Châtelier's principle, thereby significantly improving methanol production efficiency.

[0039] The shape of the separation membrane 12 can be designed in various ways, such as a planar membrane formed on the surface of a perforated flat plate as the membrane support 13, or a tubular membrane formed on the outer and / or inner surface of a perforated tube as the membrane support 13.

[0040] In the present invention, the membrane support 13, and therefore the separation membrane 12, are supported at both ends by the membrane reactor body 11. Note that "the membrane support 13 is supported at both ends by the membrane reactor body 11" means that two locations (for example, two ends) of the membrane support 13 are supported by the membrane reactor body 11, and these two locations do not have to be fixed to the membrane reactor body 11. As shown in FIG. 4, the membrane support 13 is preferably supported at both ends by making the membrane support 13 a tubular structure having a sealed end 13a and an open end 13b, one or more separation membranes 12 are disposed on the outer surface 13c and / or inner surface 13d of the membrane support 13, and the membrane reactor body 11 preferably has a fixing part 11a for fixing the open end 13b of the membrane support 13 and a supporting part 11b for supporting the sealed end of the membrane support 13 without fixing it. As a result, when the membrane reactor 1 is intended to perform reactions particularly under high pressure and high temperature, the pressure resistance of the separation membrane 12 is improved by making the membrane support 13 of the separation membrane 12 have a tubular structure, and by fixing only the open end 13b of the tubular structure and creating a support structure that allows thermal expansion of the sealed end 13a, it is possible to prevent the membrane support 13 and the separation membrane 12 from being damaged by thermal stress.

[0041] As shown in FIG. 5, it is preferable to provide a sweep pipe 31 inside a tubular membrane support 13 on which a separation membrane 12 is formed, through which a sweep fluid flows to promote separation of by-products that have permeated the separation membrane 12.

[0042] The sweep tube 31 is inserted into the tubular membrane support 13. In Fig. 5, the sweep tube 31 is supported as a cantilever, but a vibration rest may be provided at the tip of the sweep tube 31 or the like.

[0043] The sweep fluid can be liquid or gas, depending on the type of separation membrane 12 and the by-products that permeate through the separation membrane 12. In FIG. 5, the sweep fluid flows along the inner surface 13d of the membrane support 13 after being supplied into the sweep tube 31. However, the sweep fluid may also flow inside the sweep tube 31 after being supplied to the inner wall of the membrane support 13. The sweep fluid not only promotes separation of the products that permeate the separation membrane 12, but also functions as a heat transfer medium to control the temperature of the catalyst packed bed. Therefore, the flow direction of the sweep fluid can be selected appropriately, taking into consideration both the effect of sweeping the by-products that permeate the separation membrane 12 and the effect of temperature control.

[0044] The target reaction product and the raw materials thereof produced in the membrane reactor 1 can be designed to be either liquid or gas, but it can be used particularly effectively in gas-phase reactions in which the molecular weight of the raw materials used in the reaction is small and the raw materials tend to permeate (leak) through the separation membrane 12. An example of the reaction product is methanol, as shown in the above reaction formula (2).

[0045] When the membrane reactor 1 has a structure such as that shown in FIG. 3, the product flow area is narrower near the product discharge port 16 than near the raw material supply port 15. Therefore, an increase in pressure loss due to an increase in gas flow rate is expected, but the effect on pressure loss is limited when the flow resistance of the raw material and product in the catalyst packed bed is small and the pressure loss is small. Furthermore, in a reaction system in which the number of molecules decreases due to the reaction, as in the above reaction formula (2), the flow rate of the product decreases as the reaction proceeds. Therefore, the increase in pressure loss due to the narrowing of the flow area near the product discharge port 16 is mitigated, and the membrane reactor 1 according to the present invention can be used more effectively.

[0046] FIG. 6 shows a cross-sectional view of a second example of a membrane reactor according to the present invention. The membrane reactor 2 shown in FIG. 6 includes a plurality of (two in the example shown in FIG. 6) separation membranes 22 and a membrane reactor body 21 having a structure in which two membrane reactor bodies 11 shown in FIG. 3 are connected. In the membrane reactor 2 shown in FIG. 6, a raw material supply pipe 27 is connected to a raw material supply inlet 25, and a product discharge pipe 28 is connected to a product discharge outlet 26. A pre-reaction region 24a is formed from the raw material supply inlet 25 through the central region inside the membrane reactor body 21 toward the product discharge outlet 26. Most of the raw material supplied from the raw material supply inlet 25 reacts in the pre-reaction region 24, and the unreacted raw material reacts in the membrane reaction region 24b. Reaction products (e.g., methanol) produced in the pre-reaction region 24a and the membrane reaction region 24b are discharged from the product discharge outlet 26, and the produced by-products (e.g., HO) are separated by the separation membrane 22 and passed through the inside of the membrane support 23 before being discharged from the membrane reactor 2.

[0047] In the membrane reactor 2 shown in Figure 6, similarly to the membrane reactor 1 shown in Figure 3, the flow area of ​​the raw material and the product continuously narrows as it approaches the product discharge outlet 26 from the raw material supply inlet 25. Therefore, the flow rate of the product increases, particularly near the product discharge outlet 26, and the amount of reaction product and by-product passing through per unit area increases. However, since the installation density of the separation membranes 22 also increases as it approaches the product discharge outlet 26 from the raw material supply inlet 25, a decrease in the separation ability of the by-product can be suppressed.

[0048] FIG. 7 shows a cross-sectional view of a third example of a membrane reactor according to the present invention, which is a modified example of the membrane reactor shown in FIG. 6. The same components as those of the membrane reactor 2 shown in FIG. 6 are denoted by the same reference numerals. The membrane reactor 3 shown in FIG. 7 is configured such that a single raw material supply pipe 47 is inserted from a single raw material supply port 25 into the pre-reaction region 24a, and the raw material is dispersed and supplied from multiple openings O provided in the raw material supply pipe 47. This allows the raw material to be dispersed more uniformly in the pre-reaction region 24a. The configurations of the raw material supply pipes 27 and 47 are not limited to those shown in FIGS. 6 and 7, and can be designed in various ways.

[0049] Figure 8 shows a cross-sectional view of a fourth example of the membrane reactor according to the present invention. The same components as those of the membrane reactor 2 shown in Figure 6 are denoted by the same reference numerals. The membrane reactor 4 shown in Figure 8 further includes a heat transfer tube 51 for controlling the temperature of the catalyst packed bed provided in the reaction region 24, and a heat medium supply device (not shown) for supplying a heat medium into the heat transfer tube 51.

[0050] In the membrane reactor 4 shown in FIG. 8, the heat transfer tubes 51 extend in the direction of the paper surface and are arranged so that the temperature control capability of the catalyst packed bed increases from the product discharge port 26 toward the raw material supply port 25.

[0051] The heat transfer tubes 51 are used for cooling in the case of exothermic reactions and for heating in the case of endothermic reactions. They may also be used for preheating the catalyst during start-up of the membrane reactor. While a method using heat transfer tubes to supply a heat medium to maintain a constant reaction temperature in the catalyst-packed bed is commonly used, when providing a distribution of catalyst loading as in the present invention, it is necessary to separately consider the temperature control of the pre-reaction region 24a and the region near the separation membrane 22. In particular, in the pre-reaction region 24a, where raw material is supplied directly, the reaction may proceed rapidly, resulting in significant temperature changes depending on the reaction conditions. Therefore, it is preferable to increase the temperature control capacity of the heat transfer tubes 51 located near the raw material supply port 25, where the catalyst loading is high, i.e., in the region where the gaps between the separation membranes 22 are wide, compared to the temperature control capacity of the heat transfer tubes 51 located in the region where the gaps between the separation membranes 22 are narrow. The heat transfer tubes 51 can be designed in various ways, such as rectangular or circular, as long as they have the required functions, such as pressure resistance.

[0052] Methods for increasing the temperature control capability include changing the temperature of the heat medium and increasing the heat transfer area. Among these, increasing the heat transfer area is particularly effective. One method for increasing the heat transfer area is to increase the number of heat transfer tubes 51 from the product discharge port 26 toward the raw material supply port 25, as in the membrane reactor 4 shown in FIG. 8. FIG. 9 shows a cross-sectional view of a membrane reactor according to a fifth example of the present invention. Another method is to increase the total length of the heat transfer tubes 52 from the product discharge port 26 toward the raw material supply port 25, as in the membrane reactor 5 shown in FIG. 9. In FIG. 9, the same components as those in the membrane reactor 4 shown in FIG. 8 are denoted by the same reference numerals. As long as the structure can provide similar temperature control capabilities to those of the membrane reactors 4 and 5 shown in FIGS. 8 and 9, the insertion direction and arrangement of the heat transfer tubes 51 and 52 can be arbitrarily designed depending on the shape of the membrane reactors 4 and 5.

[0053] Figure 10 shows a cross-sectional view of a sixth example of a membrane reactor according to the present invention. In the membrane reactor 6 shown in Figure 10, the reactor body 61 comprises a first tube 61a and a second tube 61b housed inside the first tube 61a. A reaction region 64 is provided between the first tube 61a and the second tube 61b. A raw material supply port 65 is provided in the first tube 61a, and a product discharge port 66 is provided in the second tube 61b. A fixing portion for a membrane support 63 (separation membrane 62) is provided on one of the first tube 61a and the second tube 61b, and a support portion is provided on the other. The two-dot chain line in Figure 10 indicates that multiple units each consisting of the separation membrane 62, membrane support 63, reaction region 64, raw material supply port 65, product discharge port 66, and heat transfer tube 71 shown in Figure 10 are arranged circumferentially around the first tube 61a and the second tube 61b. Most of the raw material supplied from the raw material supply port 65 reacts in the pre-reaction region 64a, and the unreacted raw material reacts in the membrane reaction region 64b. The products produced in the pre-reaction region 64a and the membrane reaction region 64b are discharged from the product discharge port 66, and the by-products produced are separated by the separation membrane 62, pass through the inside of the membrane support 63, and are discharged from the membrane reactor 6.

[0054] The first tube 61a and the second tube 61b can be designed in various ways, such as circular or square tubes, but circular tubes are preferable to increase the pressure resistance of the reactor, especially in the case of high-pressure reactions. Also, circular tubes are easier to design from the viewpoint of uniformity of the gaps between the separation membranes 62. The first tube 61a can be designed as either an inner tube or an outer tube depending on the installation method of the separation membrane 62 and the layout of the fixing part, but it is more preferable to provide a fixing part on the first tube 61a in consideration of ease of attachment and detachment of the separation membrane 62.

[0055] The first pipe 61a and the second pipe 61b are provided with either a raw material supply port 65 or a product discharge port 66. Providing a region where the gaps between the separation membranes 62 are wider on the side of the first pipe 61a, which serves as the outer pipe, makes structural design easier, so it is preferable to provide the raw material supply port 65 in the first pipe 61a and the product discharge port 66 in the second pipe 61b, which serves as the inner pipe, as shown in Fig. 10 .

[0056] (Membrane reaction method) The membrane reaction method according to the present invention is a membrane reaction method for producing a reaction product by reacting raw materials using the above-described membrane reactor according to the present invention, characterized in that raw materials are supplied from a raw material supply port, the raw materials are reacted in a reaction region, the produced by-products are separated by a separation membrane, and the produced reaction product is discharged from a product discharge port.

[0057] As described above, in the membrane reactor 1 according to the present invention, the reaction region 14 continuously narrows from the raw material supply inlet 15 toward the product discharge outlet 16. This allows a larger reaction region 14 to be located near the raw material supply inlet 15. The pre-reaction region 14a can be located near the raw material supply inlet 15, which has a large catalyst loading, while supporting the membrane support 13, i.e., the separation membrane 12, at both ends. Using this membrane reactor 1 according to the present invention, raw materials are supplied through the raw material supply inlet 15 and reacted in the reaction region 14. The generated by-products (e.g., HO) are separated by the separation membrane 12, while the generated reaction products (e.g., methanol) are discharged through the product discharge outlet 16. Since some of the reaction proceeds in the pre-reaction region 14a, adsorption of the by-products onto the separation membrane 12 in the membrane reaction region 14b is ensured, enabling selective separation of the products by an adsorption separation method as shown in FIG. 1(b). Furthermore, damage to the separation membrane 12 due to vibration or the like can be suppressed, allowing for stable reaction of the raw materials.

[0058] 8 and 9, in the present invention, it is preferable to use a membrane reactor further including heat transfer tubes 51 and 52 for controlling the temperature of the catalyst packed bed and a heat medium supplying device for supplying a heat medium into the heat transfer tubes 51 and 52, and to supply the raw material gas while circulating the heat medium through the heat transfer tubes 51 and 52. This makes it possible to react the raw materials and produce the target reaction product while appropriately controlling the temperature of the catalyst packed bed according to the reaction in the pre-reaction region 24a.

[0059] Furthermore, in the present invention, it is preferable to use a membrane reactor in which a sweep pipe 31 for circulating a sweep fluid to promote separation of by-products that have permeated the separation membrane 12 is provided inside the membrane support 13 having an annular structure, and to supply the raw material gas while circulating the sweep fluid through the sweep pipe 31. This allows the by-products separated by the separation membrane 12 to be quickly discharged from the membrane reactor, improving the reaction efficiency. [Example]

[0060] Examples of the present invention will be described below, but the present invention is not limited to these examples.

[0061] FIG. 11 shows a cross-sectional view in the thickness direction of a membrane reactor according to an embodiment of the present invention. Components identical to those of the membrane reactor 6 shown in FIG. 10 are designated by the same reference numerals. The membrane reactor 7 shown in FIG. 11 is a membrane reactor for synthesizing methanol or the like through a gas-phase reaction. In the membrane reactor 6 shown in FIG. 10, the reaction proceeds through the flow of raw material gas in the radial direction, so it can be scaled up by increasing the number of stages in the height direction (the direction of the paper in FIG. 10). In the membrane reactor 7 shown in FIG. 11, the height positions of the raw material supply port 65 and the product discharge port 66 are offset from the height position of the separation membrane 62, but they may also be at the same height. Furthermore, the heat transfer tube 71 has a multi-tube structure that allows a heat transfer medium to flow in the height direction through the catalyst-packed layer between the separation membranes 62, as in the membrane reactor 6 shown in FIG. 10. However, as mentioned above, various configurations are possible for the installation of the heat transfer tube 71. The membrane support 63 supporting the separation membrane 62 has a fixed end on the first tube 61a side, which is the outer tube, and a free end on the second tube 61b side, which is the inner tube, that is supported at its tip by a support portion and allows thermal expansion in the longitudinal direction, thereby suppressing the generation of thermal stress due to thermal expansion during the reaction.In the membrane reactor 7 shown in Figure 11, an additional tube (third tube) 61c is provided on the outside of the first tube 61a, and between the first tube 61a and the third tube 61c, there are provided a flow path for supplying raw material to the raw material supply port 65, a flow path for supplying a sweep fluid to the sweep tube 72, and a flow path for discharging the sweep fluid discharged from the inside of the membrane support 63. [Industrial Applicability]

[0062] According to the present invention, a separation membrane can be stably supported in a membrane reactor having a pre-reaction region. [Explanation of symbols]

[0063] 1,2,3,4,5,6,7,100 Membrane reactor 11, 21, 111 Membrane reactor body 11a Fixed part 11b Support part 12,22,62,112 Separation membrane 13,23,63,113 Membrane support 13a Sealed end 13b Open end 14,24,114 Reaction region 14a, 24a, 114a Pre-reaction region 14b, 24b, 114b Membrane reaction area 15,25,115 Raw material supply port 16,26 Product outlet 17,27,47,117 Raw material supply pipe 18,28 Product discharge pipe 31,72 sweep tube 51, 52, 71 Heat transfer tubes 61a First tube 61b Second tube 61c Third Tube O opening S catalyst

Claims

1. A membrane reactor for reacting raw materials to produce a target reaction product, a membrane reactor body having a reaction region in which the raw materials are reacted, the reaction region being filled with a catalyst to form a catalyst-filled layer, a raw material supply port for supplying the raw materials to the reaction region, and a product discharge port for discharging the reaction product from the reaction region; One or more separation membranes disposed in the reaction region of the membrane reactor body, for separating by-products produced together with the reaction product by the reaction of the raw materials; one or more membrane supports supporting the one or more separation membranes; Equipped with The membrane support is supported at both ends by the membrane reactor body, A membrane reactor characterized in that the reaction zone is continuously narrowed from the raw material supply port toward the product discharge port.

2. a heat transfer tube for controlling the temperature of the catalyst packed bed; and a heat medium supply device for supplying a heat medium into the heat transfer tube, 2. The membrane reactor according to claim 1, wherein the heat transfer tubes are arranged so that the temperature control capability of the catalyst packed bed increases from the product discharge port toward the raw material supply port.

3. 3. The membrane reactor according to claim 1, wherein the membrane support has a tubular structure having a sealed end and an open end, the one or more separation membranes are disposed on an outer surface and / or an inner surface of the membrane support, and the membrane reactor body has a fixing part that fixes the open end of the membrane support and a supporting part that supports the sealed end of the membrane support.

4. The membrane reactor body comprises a first tube and a second tube housed inside the first tube, the reaction zone is provided between the first tube and the second tube, the raw material supply port is provided in one of the first tube and the second tube, and the product discharge port is provided in the other tube; The membrane reactor according to claim 3 , wherein one of the first tube and the second tube is provided with the fixed portion, and the other is provided with the support portion.

5. 4. The membrane reactor according to claim 3, wherein a sweep pipe for passing a sweep fluid therethrough is provided inside the membrane support to promote separation of the by-products that have permeated the separation membrane.

6. A membrane reaction method for producing a reaction product by reacting raw materials using the membrane reactor according to claim 1 or 2, a membrane reaction method comprising: supplying the raw materials from the raw material supply port, reacting the raw materials in the reaction region, separating the produced by-products using the separation membrane, and discharging the produced reaction products from the product discharge port.

7. The membrane reaction method according to claim 6, which relies on claim 2, wherein the raw material gas is supplied while the heat medium is circulating through the heat transfer tube.

8. The membrane reaction method according to claim 6, which is dependent on claim 5, wherein the raw material gas is supplied while the sweeping fluid is circulating through the sweeping pipe.

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