Fixed Bed Reactor

Abstract

This fixed-bed reactor comprises: a pipe which introduces a gas-liquid two-phase flow from above said fixed-bed reactor into the same; and an inlet baffle which is located inside said fixed-bed reactor, opposite an inlet for the pipe. The inlet baffle is a horizontally positioned flat plate. The inlet for the pipe is located directly above a centre position of the inlet baffle. A shielding plate, which has a shielding surface that inhibits a situation where gas-liquid two-phase flow directed at the centre position is scattered towards the outer diameter of the inlet baffle, is positioned upright on a main surface of the inlet baffle, radially outward of a position acquired by projecting the outer diameter of the inlet for the pipe onto the inlet baffle.

Description

[Technical field]

[0001] The present disclosure relates to fixed bed reactors. [Background technology]

[0002] Fixed-bed reactors are used as devices for reacting raw materials in facilities such as petrochemical plants (e.g., Patent Document 1). In such fixed-bed reactors, a reaction layer is arranged in the lower part and a raw material introduction layer is arranged in the upper part, and raw materials are supplied into the reactor from a pipe connected to the upper part. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2007-112745 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the fixed-bed reactor described in Patent Document 1, a disk-shaped inlet baffle is disposed in the raw material introduction layer directly below the inlet of the piping to the fixed-bed reactor, and the raw material supplied from above to the inside is temporarily received by the inlet baffle. For example, depending on the installation conditions of the fixed-bed reactor, such as the shape of the piping and the bending position, the raw material may not be supplied evenly to the entire main surface of the inlet baffle. In this case, the raw material does not diffuse evenly inside the fixed-bed reactor, causing uneven supply to the reaction layer, which may result in a decrease in production volume.

[0005] An object of the present disclosure is to provide a fixed bed reactor capable of uniformly diffusing raw materials fed therein. [Means for solving the problem]

[0006] The present disclosure has the following configuration.

[0007] [1] A fixed-bed reactor according to one aspect of an embodiment of the present invention comprises a piping for introducing a gas-liquid two-phase flow from an upper portion of the fixed-bed reactor into the interior thereof, and an inlet baffle arranged inside the fixed-bed reactor facing an inlet of the piping to the fixed-bed reactor, wherein the inlet baffle is a horizontally arranged flat plate, the inlet of the piping is arranged directly above a central position of the inlet baffle, and a shielding portion having a shielding surface facing the central position on a main surface of the inlet baffle and suppressing the gas-liquid two-phase flow from scattering to an outer diameter side of the inlet baffle is arranged radially outward from a position where the outer diameter of the inlet of the piping is projected onto the inlet baffle, and is erected upward.

[0008] [2] The piping is a curved pipe having a horizontal section extending horizontally and a vertical section bent at a substantially right angle from the horizontal section and connected to the fixed-bed reactor, The shielding portion is disposed on the opposite side to the extending direction of the horizontal portion. The fixed bed reactor according to [1].

[0009] [3] The shielding surface is disposed directly opposite the axial direction of the horizontal portion of the pipe. The fixed bed reactor according to [2].

[0010] [4] The inlet baffle is a polygonal flat plate or a circular plate. The fixed bed reactor according to any one of [1] to [3].

[0011] [5] The shape of the shielding surface is flat or curved. The fixed bed reactor according to any one of [1] to [4].

[0012] [6] The shielding portion is a plate-shaped member. The fixed bed reactor according to any one of [1] to [5].

[0013] [7] The shape of the shielding part is flat, arcuate, or cylindrical. [6] The fixed bed reactor according to claim 1.

[0014] [8] When the normal direction of the shielding surface is horizontal and the inclination angle of the shielding surface with respect to the main surface of the inlet baffle is 90 degrees, the inclination angle of the shielding surface transitions to the 0 degree side when the shielding surface inclines toward the center of the inlet baffle, and the inclination angle of the shielding surface transitions to the 180 degree side when the shielding surface inclines toward the outer edge of the inlet baffle, The inclination angle of the shielding surface is in the range of 40 degrees to 115 degrees. The fixed bed reactor according to any one of [1] to [7].

[0015] [9] The inclination angle of the shielding surface is in the range of 85 degrees to 110 degrees. [8] The fixed bed reactor according to claim 1.

[0016]

[10] The inclination angle of the shielding surface is 90 degrees. [8] or [9]. A fixed bed reactor according to the present invention.

[0017]

[11] The normal direction of the shielding surface is horizontal, The extension direction of the shielding surface is a vertical direction from the inlet baffle. The fixed bed reactor according to any one of [1] to [7]. Effect of the Invention

[0018] According to the present disclosure, it is possible to provide a fixed bed reactor capable of uniformly diffusing raw materials supplied therein. [Brief description of the drawings]

[0019] [Figure 1] FIG. 1 is a vertical cross-sectional view showing a schematic configuration of a fixed bed reactor according to an embodiment. [Diagram 2] FIG. 1 is a plan view showing the configuration of the raw material introduction layer of a fixed bed reactor according to an embodiment. [Diagram 3] An enlarged perspective view of the vicinity of the raw material introduction layer of a fixed-bed reactor. [Figure 4] Schematic diagram showing the range of the upright direction of the shielding plate [Diagram 5] Schematic diagram showing symbols corresponding to each dimension in a fixed bed reactor. [Figure 6] FIG. 13 is a diagram showing a first modified example of the shielding plate. [Figure 7] FIG. 13 is a diagram showing a second modified example of the shielding plate. [Figure 8] FIG. 1 shows droplet flux distributions for Example 1 and Comparative Example 1. [Figure 9] FIG. 13 is a graph showing the relationship between the inclination angle of the shielding plate and the rate of improvement in uneven distribution of droplet flux. [Figure 10] FIG. 1 shows droplet flux distributions for Example 2 and Comparative Example 2. [Figure 11] FIG. 13 shows droplet flux distribution in Comparative Example 3. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Hereinafter, an embodiment will be described with reference to the accompanying drawings. In order to facilitate understanding of the description, the same components in each drawing are denoted by the same reference numerals as much as possible, and duplicated description will be omitted.

[0021] In the following description, the x, y, and z directions are perpendicular to each other. The x and y directions are horizontal, and the z direction is vertical. The x direction is the axial direction of the horizontal portion 41 of the pipe 4. When the normal direction of the shielding surface 61 is horizontal, the inclination angle of the shielding surface 61 with respect to the main surface 51 of the inlet baffle 5 is 90 degrees, and the x direction is the normal direction of the shielding surface 61 when the inclination angle of the shielding surface 61 is 90 degrees. When the shielding plate 6 is a flat plate, the y direction is the longitudinal direction of the shielding plate 6. For convenience of description, the positive z direction may be referred to as the upper side and the negative z direction may be referred to as the lower side.

[0022] A schematic configuration of a fixed-bed reactor 1 according to an embodiment will be described with reference to Figs. 1 to 3. Fig. 1 is a vertical cross-sectional view showing a schematic configuration of the fixed-bed reactor 1 according to an embodiment. Fig. 2 is a plan view showing a configuration inside a raw material introduction layer 2 of the fixed-bed reactor 1 according to an embodiment. Fig. 3 is an enlarged perspective view of the vicinity of the raw material introduction layer 2 of the fixed-bed reactor 1.

[0023] FIG. 1 shows an example of a fixed-bed reactor that is a multi-tubular fixed-bed reactor. In the fixed-bed reactor 1, a raw material introduction layer 2 is arranged in the upper part, and a reaction layer 3 is arranged in the lower part. The raw material introduction layer 2 and the reaction layer 3 are separated by a tube plate surface 7. A pipe 4 is connected to the upper end of the raw material introduction layer 2, which introduces a gas-liquid two-phase flow M (a mixed fluid composed of a gas as a continuous phase and liquid droplets as a dispersed phase) as a raw material into the raw material introduction layer 2. In the fixed-bed reactor 1, the raw material supplied to the raw material introduction layer 2 through the pipe 4 is reacted with a catalyst in the reaction layer 3, and the reaction product is discharged from the lower part. In the case of the multi-tubular fixed-bed reactor shown in FIG. 1, the reaction layer 3 is composed of a reaction tube 8 filled with a solid catalyst or the like and a heat medium circulation part that is provided outside the reaction tube 8 and heats and removes heat from the reaction tube 8. The fixed-bed reactor is not limited to the multi-tubular reactor, and may be a reactor in which all of the reaction layers are filled with a solid filler or a solid catalyst.

[0024] The pipe 4 is preferably a curved pipe having a horizontal section 41 extending horizontally and a vertical section 42 bent at a substantially right angle from the horizontal section 41 and connected to the fixed-bed reactor 1. An example of the pipe 4 having such a structure is a single-elbow type pipe in which two straight pipes are connected by a joint pipe (elbow) bent at 90 degrees. Note that a type of pipe other than a single elbow, such as a double elbow type, may be used for the pipe 4.

[0025] In this embodiment, the horizontal part 41 of the pipe 4 is arranged so that its axis is in the x direction, and the vertical part 42 is arranged so that its axis is in the z direction. The cross-sectional shape of the pipe 4 is also approximately circular, the fixed-bed reactor 1 is approximately cylindrical with its central axis in the z direction, and the vertical part 42 of the pipe 4 is connected to the center of the fixed-bed reactor 1 so that its axis overlaps with the center position C of the approximately circular end face at the upper part of the pipe 4.

[0026] With such a configuration of the piping 4, the gas-liquid two-phase flow M passing through the piping 4 is introduced vertically downward from above into the center of the fixed-bed reactor 1, as shown in FIG.

[0027] An inlet baffle 5 is provided inside the raw material introduction layer 2. The inlet baffle 5 is a flat plate arranged horizontally, and one main surface 51 is arranged facing vertically upward (z positive direction). The inlet baffle 5 has a disk shape in FIG. 1 and is arranged opposite the inlet 43 of the pipe 4 to the fixed bed reactor 1. More specifically, the inlet 43 of the pipe 4 is arranged directly above the center position C of the inlet baffle 5. The center position C of the circular main surface 51 of the inlet baffle 5 is the same position as the center position C of the fixed bed reactor 1 described above. That is, in a plan view, the inlet 43 of the pipe 4, the inlet baffle 5, and the outer shape of the fixed bed reactor 1 are arranged concentrically as shown in FIG. 2.

[0028] The inlet baffle 5 is disposed between the inlet 43 of the pipe 4 and the reaction bed 3 in order to prevent the raw material M introduced from the pipe 4 from directly colliding with the reaction bed 3 below and damaging the reaction bed 3. The inlet baffle 5 is generally provided perpendicular to the flow of the gas-liquid two-phase flow M for the purpose of buffering. As a result, as shown in Fig. 1, the raw material M introduced from the pipe 4 first collides with the inlet baffle 5, is reflected, and is decelerated before being supplied to the reaction bed 3.

[0029] In particular, in this embodiment, a shielding plate 6 (shielding portion) is erected upward on the main surface 51 of the inlet baffle 5. The shielding plate 6 has a shielding surface 61 facing the center position C of the inlet baffle 5. As indicated by the symbol A in Fig. 1, the shielding surface 61 receives a part of the gas-liquid two-phase flow M that is reflected at the center position C of the inlet baffle 5 and moves radially outward (the x negative direction side in the example of Fig. 1), and reflects it in the opposite direction (the x positive direction side in the example of Fig. 1). In this way, the shielding surface 61 partially suppresses the gas-liquid two-phase flow M from scattering toward the outer diameter side of the inlet baffle 5.

[0030] In the fixed bed reactor 1 of the present embodiment, the baffle plate 6 is provided so as to obstruct the flow of the gas-liquid two-phase flow M, so that the raw material M supplied to the inside can be uniformly diffused.

[0031] The inlet baffle 5 is preferably a polygonal flat plate or disk, more preferably a disk. If it is a polygonal flat plate, it is preferably a regular polygon having a contour close to a circle and many vertices, and preferably the number of vertices exceeds 10,000.

[0032] The shielding plate 6 is preferably a flat plate-like member, and one of its main planes functions as the shielding surface 61. In this case, the shape of the shielding plate 6 and the shielding surface 61 is a rectangle with the y direction as the longitudinal direction.

[0033] The shielding plate 6 is preferably arranged so that the normal direction of the shielding surface 61 is horizontal, and when the shielding plate 6 is a flat plate, the extending direction of the shielding surface 61 is vertical from the inlet baffle 5 .

[0034] It is preferable that the shielding surface 61 of the shielding plate 6 is disposed so as to face directly in the axial direction (x direction) of the horizontal portion 41 of the pipe 4.

[0035] As shown in FIG. 2, the shielding plate 6 is preferably disposed radially outward from the position where the outer diameter of the inlet 43 of the pipe 4 is projected onto the inlet baffle 5 .

[0036] The fixed bed reactor 1 of this embodiment has such a configuration of the baffle plate 6, so that the raw material M supplied inside can be diffused more evenly.

[0037] The effect of the shield plate 6 in diffusing and equalizing the gas-liquid two-phase flow M is particularly remarkable when the pipe 4 is a single elbow type as shown in FIG. 1 and the like. In the case of the single elbow type pipe 4, the gas-liquid two-phase flow M flows into the reactor after being bent 90 degrees just before the reactor inlet due to the elbow shape, and is considered to be strongly affected by the inertia due to the bending of the elbow shape. For this reason, in the conventional reactor, the gas-liquid two-phase flow in the raw material introduction layer 2 is supplied in a strongly uneven manner to the moving direction side of the horizontal part 41 of the pipe 4, that is, the region opposite the horizontal part 41 across the center position C in a plan view (the x negative direction side in this embodiment) (see FIG. 8(A) and FIG. 10(A)). In this embodiment, the shield plate 6 can suppress the gas-liquid two-phase flow M from flowing in the direction of the region, and as a result, it is considered that the diffusion and equalization of the gas-liquid two-phase flow M can be promoted. Furthermore, the gas-liquid two-phase flow M is uniformly diffused in the fixed-bed reactor 1 in the outer circumferential direction of the inlet baffle 5, thereby improving the production amount of the reaction product.

[0038] The shielding plate 6 may be erected at an incline with respect to the inlet baffle 5. FIG. 4 is a schematic diagram showing the range of erection directions of the shielding plate 6. As shown in FIG. 4, when the normal direction of the shielding surface 61 is horizontal, the inclination angle of the shielding surface 61 with respect to the main surface 51 of the inlet baffle 5 is 90 degrees. In addition, when the shielding surface 61 is inclined toward the center C of the inlet baffle 5, the inclination angle of the shielding surface 61 transitions to the 0 degree side, and conversely, when the shielding surface 61 is inclined toward the outer edge side of the inlet baffle 5, the inclination angle of the shielding surface 61 transitions to the 180 degree side. When the shielding plate 6 is flat, the extension direction of the shielding surface 61 is a vertical direction from the inlet baffle 5. In this case, as shown by the angle range R1 in FIG. 4, the inclination angle of the shielding surface 61 is preferably in the range of 40 degrees to 115 degrees. Moreover, as shown by angle range R2 in Fig. 4, it is more preferable that the inclination angle of the shielding surface 61 is in the range of 85 degrees to 110 degrees. Moreover, it is even more preferable that the inclination angle of the shielding surface 61 is 90 degrees.

[0039] By setting the inclination angle of the shielding surface 61 in this way, the raw material M supplied to the inside of the fixed bed reactor 1 can be diffused more uniformly.

[0040] Fig. 5 is a schematic diagram showing symbols corresponding to the dimensions in the fixed-bed reactor 1. Fig. 5(A) is a vertical cross-sectional view similar to Fig. 1, and Fig. 5(B) is a plan view similar to Fig. 2.

[0041] As shown in Figures 5(A) and (B), the pipe diameter is d and the reactor diameter is D. As shown in Figure 5(A), the vertical coordinate of the inlet baffle 5 based on the tube plate surface 7 is h, the height from the tube plate surface 7 to the joint between the pipe 4 and the reactor 1 is H, and the height of the shielding plate 6 in the z direction is E. As shown in Figure 5(B), the distance from the center position C of the inlet baffle 5 to the shielding plate 6 is L, the diameter of the inlet baffle 5 is F, and the width of the shielding plate 6 in the longitudinal direction (y direction) is G.

[0042] The diameter F of the inlet baffle 5 is preferably 0.3D or more and 0.4D or less. The installation position h / H (0≦h / H≦1) of the inlet baffle 5 is preferably 0.2 or more and 0.8 or less. The distance L from the center position C of the shielding plate 6 is preferably larger than the pipe diameter d. The width G of the shielding plate 6 is preferably larger than the pipe diameter d. The height E of the shielding plate 6 is preferably 0.2H or more and is a dimension that does not contact the upper wall surface of the reactor 1.

[0043] In this embodiment, the gas-liquid two-phase flow M of the raw material preferably has a fluid velocity of 8 to 15 m / s when passing through the pipe 4. The liquid droplet concentration of the gas-liquid two-phase flow M is preferably less than 10% by volume.

[0044] By applying these various parameter conditions, the raw material M supplied to the inside of the fixed bed reactor 1 can be diffused more uniformly.

[0045] Fig. 6 is a diagram showing a first modified example of the shielding plate 6A. As shown in Fig. 6, the shielding plate 6A may be arc-shaped. The arc shape of the shielding plate 6A is formed around the center position C of the inlet baffle 5. In this case, the shielding surface 61A has a curved shape that follows the arc shape.

[0046] The arc-shaped shielding plate 6A of the first modified example is effective for satisfying the condition that the longitudinal width H of the shielding plate 6A is larger than the pipe diameter d when the diameter F of the inlet baffle 5 is less than √2d, that is, when the plate width G for the pipe diameter d cannot be obtained if the shielding plate is flat. The width J of the shielding plate 6A is preferably equal to or greater than πd / 2 and less than πd / √2. When the arc-shaped shielding plate 6A is erected at an incline, it is preferable that the shielding surface 61A is uniformly inclined.

[0047] FIG. 7 is a diagram showing a second modified example of the shielding plate 6B. As shown in FIG. 7, the shielding plate 6B may be cylindrical. The cylindrical shape of the shielding plate 6B is formed with the center at the center position C of the inlet baffle 5. In this case, the shielding surface 61B is the inner peripheral surface of the cylindrical shape and is curved. The inner diameter of the cylindrical shape of the shielding plate 6B is preferably larger than the pipe diameter d. When the cylindrical shielding plate 6B is erected at an incline, it is preferable that the shielding surface 61B is uniformly inclined.

[0048] The fixed bed reactor applied to this embodiment may be of single-tube or multi-tube type. In the case of a single-tube reactor, there is no restriction on the outer diameter or length of the reactor, and it is arbitrarily determined from the viewpoint of ensuring the mass velocity and material diffusion into the reactor. In a fixed bed flow reaction in which the reaction raw material is continuously contacted with a heterogeneous solid catalyst, if the reaction is accompanied by exothermic or endothermic heat, a multi-tube reactor is usually used. In the case of a multi-tube reactor, a cylindrical straight tube having the same outer diameter, wall thickness and length is usually used as the reaction tube, and the inner diameter of the reaction tube is preferably determined to be 4 times or more the diameter of the catalyst to be filled, and is industrially selected from the range of about 15 to 50 mm, but is not particularly limited.

[0049] There is no particular limitation on the reaction to which the fixed bed reactor of the present embodiment can be applied. Any reaction that is generally carried out in a fixed bed reactor may be used, such as the production of ethylene oxide by oxidation of ethylene, the production of acrolein and acrylic acid by oxidation of propylene, the production of methacrolein and methacrylic acid by oxidation of isobutylene, the production of maleic anhydride by oxidation of benzene, the production of ethyleneimine by dehydration of monoethanolamine, the production of N-vinyl-2-pyrrolidone by dehydration of N-(2-hydroxyethyl)-2-pyrrolidone, the production of acrylonitrile by ammoxidation of propylene, and the production of acetic acid by direct addition of acetic acid to ethylene. Examples of the method include the production of ethyl acetate, the production of vinyl acetate by oxidative acetoxylation of ethylene, the production of allyl acetate by oxidative acetoxylation of propylene, the production of ethylene by hydrogenation of acetylene, the production of cyclohexane by hydrogenation of benzene, the production of styrene monomer by hydrogenation of ethylbenzene, the production of propylene by dehydrogenation of propane, the production of 2-butene by isomerization of 1-butene, the production of allyl alcohol by isomerization of propylene oxide, the production of ethanol by hydration of ethylene, the production of 2-propanol by hydration of propylene, etc. In addition, application to a type of reaction in which a gas-liquid two-phase flow is introduced into a reactor is more preferable, and specific examples include the production of vinyl acetate by oxidative acetoxylation of ethylene and the production of allyl acetate by oxidative acetoxylation of propylene. EXAMPLES

[0050] A calculation simulation was performed to confirm the effectiveness of the above embodiment. The main calculation conditions are as follows. Software used: ANSYS (registered trademark) Fluent (registered trademark), a general-purpose computational fluid analysis software made by ANSYS · Continuous phase (gas = vapor phase) governing equation: N-S equation, continuity equation Turbulence model: k-ε model Gas-liquid two-phase flow analysis: Euler-Lagrange type (gas fluid is analyzed using the Euler type, liquid droplets using the Lagrange type) Dispersed phase flow: Liquid phase Particle Tracking Method (DPM (Discrete Phase Model)): One Way Coupling Analytical objects: Pipes and reactors

[0051] (1) Example 1 The ratio of the pipe diameter d, the diameter of the circular bottom plate (diameter F of the inlet baffle 5), and the reactor diameter D was 1:5:20. The position h / H of the inlet baffle 5 was 0.4. The shape of the shielding plate 6 was flat, with a height E of 0.2H and a width G of 0.2D. The flow velocity of the gas-liquid two-phase flow M was 10 m / s, and the droplet concentration was 5 mass%. Under these conditions, the droplet flux distribution in the plan view of the raw material introduction layer 2 of the fixed bed reactor 1 was measured. The droplet flux is the product of the droplet concentration and the vertical gas flow velocity (droplet concentration x gas flow velocity).

[0052] (2) Comparative Example 1 The conditions were the same as in Example 1, except that the shielding plate 6 was not provided.

[0053] Fig. 8 is a diagram showing droplet flux distribution in a plane including the main surface 51 of the inlet baffle 5 of Example 1 and Comparative Example 1. Fig. 8(A) shows the result of Comparative Example 1, and (B) shows the result of Example 1. Fig. 8 illustrates a distribution approaching white as the droplet flux decreases, and approaching black as the droplet flux increases.

[0054] As shown in FIG. 8A, without the shielding plate 6, the droplet flux is biased to the left side of the figure (the area opposite the horizontal part 41 of the pipe 4), and the standard deviation of the droplet flux over the entire plane is 3.7×10 -5 It can be seen that there is unevenness in the droplet flux across the entire plane. On the other hand, as shown in FIG. 8(B), when the shielding plate 6 is present, there are fewer dark areas compared to (A), and it can be seen that the overall unevenness is suppressed. The standard deviation of the droplet flux across the entire plane is 1.3×10 -5 This reduces the size to about 1 / 3 compared to (A) where there is no shielding plate 6.

[0055] As described above, the results of Example 1 and Comparative Example 1 shown in FIG. 8 show that by providing the shielding plate 6 to the inlet baffle 5, the droplet flux distribution in the plan view of the raw material introduction layer 2 of the fixed-bed reactor 1 can be made uniform, and the gas-liquid two-phase flow M of the raw material supplied inside can be uniformly diffused.

[0056] (3) Inclination angle of the shielding plate Furthermore, the conditions were the same as in Example 1, except that the inclination angle of the shielding plate 6 was changed. The inclination angles of the shielding plate 6 were 15 degrees, 30 degrees, 45 degrees, 75 degrees, 90 degrees, 110 degrees, and 120 degrees, under the conditions described with reference to FIG. 4. At each inclination angle, a simulation similar to that of Example 1 was performed to measure the droplet flux distribution, and the standard deviation of the droplet flux was calculated. The standard deviation of Comparative Example 1 without the shielding plate 6 was used as a reference (base), and the reduction rate of the standard deviation for each inclination angle was calculated as the improvement rate of the droplet flux uneven distribution relative to the comparative example (improvement rate relative to the base).

[0057] Fig. 9 is a diagram showing the relationship between the tilt angle of the shielding plate 6 and the improvement rate of uneven distribution of droplet flux. The horizontal axis of Fig. 9 represents the tilt angle (°) of the shielding plate 6. The vertical axis of Fig. 9 represents the improvement rate relative to the base.

[0058] As shown in Fig. 9, when the tilt angle is in the range of 40 degrees to 115 degrees, the improvement rate is 50% or more, which shows that the effect of improving the uneven distribution of the droplet flux is sufficient. Also, when the tilt angle is in the range of 85 degrees to 110 degrees, the improvement rate is 60% or more, which shows that the effect of improving the uneven distribution of the droplet flux is even more pronounced. Furthermore, when the tilt angle is 90 degrees, the improvement rate is the largest, which shows that the effect of improving the uneven distribution of the droplet flux is the largest.

[0059] Thus, the simulation results shown in FIG. 9 show that the inclination angle of the shielding plate 6 (shielding surface 61) is preferably in the range of 40 degrees to 115 degrees, more preferably in the range of 85 degrees to 110 degrees, and even more preferably 90 degrees.

[0060] (4) Example 2 The ratio of the pipe diameter d, the diameter of the circular bottom plate (diameter F of the inlet baffle 5), and the reactor diameter D was set to 3:4:10, and the shape of the shielding plate 6A was set to an arc shape, but other conditions were the same as in Example 1, and the droplet flux distribution in the plan view of the raw material introduction layer 2 of the fixed bed reactor 1 was measured in the same manner as in Example 1. The width J of the shielding plate 6A was set to 0.42D.

[0061] (5) Comparative Example 2 The conditions were the same as in Example 2, except that the shielding plate 6A was not provided.

[0062] Fig. 10 is a diagram showing droplet flux distribution in a plane including the main surface 51 of the inlet baffle 5 of Example 2 and Comparative Example 2. (A) in Fig. 10 shows the results of Comparative Example 2, and (B) shows the results of Example 2. The display mode of the flow velocity distribution in Fig. 10 is the same as that in Fig. 8.

[0063] As shown in FIG. 10A, without the shielding plate 6A, the droplet flux is biased to the left side of the figure (the area opposite the horizontal part 41 of the pipe 4), and the standard deviation of the droplet flux over the entire plane is 9.7×10 -3 It can be seen that there is unevenness in the droplet flux across the entire plane. On the other hand, as shown in FIG. 10(B), when the shielding plate 6A is present, the number of dark areas is reduced compared to (A), and it can be seen that the overall unevenness is suppressed. The standard deviation of the droplet flux across the entire plane is 2.0×10 -3 This reduces the size to about 1 / 5 compared to (A) where there is no shielding plate 6.

[0064] As described above, the results of Example 2 and Comparative Example 2 shown in FIG. 10 show that the provision of the arc-shaped shielding plate 6A on the inlet baffle 5 can also uniformize the droplet flux distribution in the plan view of the raw material introduction layer 2 of the fixed-bed reactor 1, and can uniformly diffuse the gas-liquid two-phase flow M of the raw material supplied inside.

[0065] (6) Comparative Example 3 Except for the point that the shielding plate 6A was disposed inside the pipe diameter d, the conditions were the same as those in Example 2. The width J of the shielding plate 6A was set to 0.27D.

[0066] Fig. 11 is a diagram showing the droplet flux distribution in a plane including the main surface 51 of the inlet baffle 5 of Comparative Example 3. The display mode of the flow velocity distribution in Fig. 11 is the same as Figs. 8 and 10. From the results of Comparative Example 3 shown in Fig. 11, when the shielding plate 6A is located inside the pipe 4, the standard deviation of the droplet flux is 5.0 × 10 -3 Although the size can be reduced to about half compared to Comparative Example 2, the droplet flux distribution shows a bias similar to that in the case of no shielding plate 6A in Comparative Example 2. For this reason, it was shown that it is preferable to arrange the shielding plates 6, 6A, and 6B radially outward from the position where the outer diameter of the inlet 43 of the pipe 4 is projected onto the inlet baffle 5, as shown in Figures 2, 6, and 7.

[0067] The present embodiment has been described above with reference to specific examples. However, the present disclosure is not limited to these specific examples. Any design modifications made by a person skilled in the art to these specific examples are also included within the scope of the present disclosure as long as they have the features of the present disclosure. The elements of each of the above-mentioned specific examples and their arrangements, conditions, shapes, etc. are not limited to those exemplified and can be changed as appropriate. The combination of each of the elements of each of the above-mentioned specific examples can be changed as appropriate as long as no technical contradiction occurs.

[0068] In the above embodiment, a configuration in which the shielding plate 6 made of a plate-like member is provided on the inlet baffle 5 has been exemplified, but any configuration having a shielding surface 61 that suppresses the gas-liquid two-phase flow M from scattering to the outer diameter side of the inlet baffle 5 may be used other than a plate-like member. For example, a block-shaped shielding portion such as a rectangular parallelepiped or cube may be provided on the main surface 51 of the inlet baffle 5 instead of the shielding plate 6, and this block-shaped shielding portion may have the shielding surface 61.

[0069] This international application claims priority to Japanese Patent Application No. 2020-211664, filed on December 21, 2020, the entire contents of which are hereby incorporated by reference into this international application. [Explanation of symbols]

[0070] 1 Fixed bed reactor 4 Piping 41 Horizontal part 42 Vertical section 5 Inlet baffle 6, 6A, 6B Shielding plate (shielding part) 7 Tube plate surface 8 Reaction tube 61, 61A, 61B shielding surface

Claims

1. A fixed bed reactor comprising: The fixed bed reactor is a fixed bed multi-tubular reactor, A pipe for introducing a gas-liquid two-phase flow into the fixed bed reactor from an upper portion thereof; an inlet baffle disposed inside the fixed bed reactor opposite an inlet of the piping to the fixed bed reactor; The liquid phase of the gas-liquid two-phase flow is droplets, the piping is a curved pipe having a horizontal portion extending horizontally and a vertical portion bent at a substantially right angle from the horizontal portion and connected to the fixed-bed reactor, the inlet baffle being a horizontally disposed flat plate; The inlet of the piping is disposed directly above the center position of the inlet baffle, a shielding portion having a shielding surface facing the center position and suppressing the gas-liquid two-phase flow from scattering toward an outer diameter side of the inlet baffle is disposed radially outward from a position where an outer diameter of the inlet port of the piping is projected onto the inlet baffle on a main surface of the inlet baffle, and is erected upward, The shielding portion is disposed on the opposite side to the extending direction of the horizontal portion. Fixed bed reactor.

2. The shielding surface is disposed directly opposite the axial direction of the horizontal portion of the pipe.

2. The fixed bed reactor of claim 1.

3. The inlet baffle is a polygonal flat plate or a circular plate.

3. The fixed bed reactor according to claim 1 or 2.

4. The shape of the shielding surface is flat or curved. The fixed bed reactor according to any one of claims 1 to 3.

5. The shielding portion is a plate-shaped member. The fixed bed reactor according to any one of claims 1 to 4.

6. The shape of the shielding portion is flat, arcuate, or cylindrical.

6. The fixed bed reactor of claim 5.

7. When the normal direction of the shielding surface is horizontal and the inclination angle of the shielding surface with respect to the main surface of the inlet baffle is 90 degrees, the inclination angle of the shielding surface transitions to the 0 degree side when the shielding surface inclines toward the center of the inlet baffle, and the inclination angle of the shielding surface transitions to the 180 degree side when the shielding surface inclines toward the outer edge of the inlet baffle, The inclination angle of the shielding surface is in the range of 40 degrees to 115 degrees. The fixed bed reactor according to any one of claims 1 to 6.

8. The inclination angle of the shielding surface is in the range of 85 degrees to 110 degrees.

8. The fixed bed reactor of claim 7.

9. The inclination angle of the shielding surface is 90 degrees.

9. The fixed bed reactor according to claim 7 or 8.

10. a normal direction of the shielding surface is a horizontal direction; The extension direction of the shielding surface is a vertical direction from the inlet baffle. The fixed bed reactor according to any one of claims 1 to 6.

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