Catalyst molding

Abstract

The present invention relates to a catalyst molded body comprising a columnar body extending in a longitudinal direction and having a cross section perpendicular to the longitudinal direction. The cross section has a central through hole, at least four first corners, and the same number of first recesses as the first corners, the at least four first corners being arranged at equal angular intervals along the circumferential direction to define a first circumscribing circle of the outer contour of the catalyst molded body, each first corner being tangent to the first circumscribing circle, the at least four first corners being rotationally symmetrical with respect to the center of the first circumscribing circle, the first corners and the first recesses being arranged alternately in the circumferential direction, the first corners and the first recesses having different geometric shapes to avoid interlocking between the first corners and / or first recesses of one catalyst molded body and the first recesses and / or first corners of an adjacent catalyst molded body, the first corners being outwardly convex portions of a first ellipse having a ratio of major axis to minor axis greater than 1.2, and the first recesses being inwardly concave arcs tangent to two adjacent first corners.

Description

[Technical Field]

[0001] The present invention relates to catalysts, and more particularly to shaped catalyst bodies. [Background technology]

[0002] The information disclosed in this background section is merely intended to enhance understanding of the overall background of the invention and should in no way be considered as an admission or suggestion that the information constitutes prior art already known to those skilled in the art.

[0003] Catalysts are usually preformed into catalyst molds and then packed into reactor tubes for catalytic applications. Different preformed shapes of catalysts will affect their performance. Conventional catalyst shapes include cylindrical, Raschig ring, cloverleaf, four-leaf clover, toothed ball, and bird's nest shape.

[0004] At present, cylindrical catalysts or hollow cylindrical catalysts are common in the industry. However, cylindrical catalyst particles have channel flow and wall flow phenomena, which cause uneven gas flow during passage, adversely affecting reaction efficiency; and the outer surface area is small, resulting in low catalyst production capacity. At the same time, the pressure drop of cylindrical catalyst particles is relatively large, which causes relatively large energy consumption for production equipment.

[0005] In recent years, irregularly shaped catalyst particles have been proposed, and the irregularly shaped structure increases the porosity of the catalyst bed layer in order to reduce the catalyst pressure drop in the reactor bed layer and improve the catalyst production capacity. However, existing irregularly shaped catalyst moldings have complex structures and are not easy to manufacture and shape. The irregular edges and corners are easily worn during transportation and use, have low mechanical strength, insufficient crush resistance, insufficient abrasion resistance, and it is difficult to ensure structural integrity during catalyst transportation, packing, and high space velocity operation. Catalyst breakage and wear will further increase the pressure drop in the catalyst bed layer, and instead increase the energy consumption load of the production equipment.

[0006] Chinese Patent Publication No. 102784666 discloses a solid catalyst particle, the outer contour of which in the radial cross section is continuous and has a smoothly undulating shape. This continuous, smoothly undulating outer contour is composed of curved segments with the following characteristics: a group of circles with a number (N) and a radius (α), which form a circumscribing circle of three circles consisting of the inscribed circle of the outer contour and two adjacent circles with a radius (α), and these circumscribing circles form another group of circles with the same number (N), and the circles from these two groups with the same number (N) circumscribing each other, two corresponding tangent points are formed on each circle, and minor arcs are obtained between the two tangent points, and all these minor arcs are connected end to end to form this continuous, smoothly undulating outer contour of the cross section. However, the outwardly convex and inwardly concave arcs of the outer contours of adjacent catalyst particles interdigitate with each other, thereby increasing the contact area between the catalyst particles. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Chinese Patent Application Publication No. 102784666 Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention is intended to provide a catalyst molding that can reduce the contact area between catalyst particles, avoid interlocking between the outwardly convex arcs and the inwardly concave arcs of the outer contour of the particles, increase the porosity of the bed layer, and reduce the filling packing ratio of the catalyst bed layer. [Means for solving the problem]

[0009] According to one aspect of the present invention, there is provided a molded catalyst body comprising longitudinally extending pillars, the pillars having a cross section perpendicular to the longitudinal direction. The cross section has a central through hole, at least four first corners, and the same number of first recesses as the first corners, the at least four first corners being arranged at equal angular intervals in the circumferential direction so as to define a first circumscribing circle of the outer contour of the catalyst molded body, each first corner being tangent to the first circumscribing circle, and the at least four first corners being rotationally symmetrical with respect to the center of the first circumscribing circle, the first corners and the first recesses being arranged alternately in the circumferential direction, the first corners and the first recesses having different geometric shapes to avoid interlocking between the first corners and / or first recesses of one catalyst molded body and the first recesses and / or first corners of an adjacent catalyst molded body, the first corners being outwardly convex portions of a first ellipse having a ratio of major axis to minor axis greater than 1.2, and the first recesses being inwardly concave arcs tangent to two adjacent first corners.

[0010] Preferably, a line connecting the center of the first ellipse and the center of the first circumscribing circle is perpendicular to the major axis of the first ellipse, and the ratio of the length of the major axis of the first ellipse to the radius of the first circumscribing circle is 0.2 to 1.

[0011] Preferably, the central through hole has second corners in the same number as the first corners and second recesses in the same number as the first recesses, the second corners define a second circumscribing circle of the central through hole, the first corners and the second corners are aligned in the circumscribing direction, each second corner is tangent to the second circumscribing circle and the second corners are rotationally symmetrical with respect to the center of the second circumscribing circle, the first recesses and the second recesses are aligned in the circumscribing direction, each second corner is an outwardly convex portion of a second ellipse, and the second recesses are inwardly concave arcs tangent to two adjacent second corners.

[0012] Preferably, the ratio of the major axis to the minor axis of the second ellipse is equal to the ratio of the major axis to the minor axis of the first ellipse.

[0013] Preferably, the ratio of the area of ​​the second circumscribing circle of the central through-hole to the area of ​​the first circumscribing circle of the outer contour of the catalyst molded article is 0.17 to 0.34.

[0014] Preferably, each first recess is tangent to the first inscribed circle, the first ellipse corresponding to each first corner is tangent to a second inscribed circle, the first inscribed circle and the second inscribed circle are concentric with the first circumscribed circle, and the radius of the first inscribed circle is larger than the radius of the second inscribed circle.

[0015] Preferably, the height of the catalyst molded body in the longitudinal direction is equal to or greater than the radius of the first circumscribing circle of the outer contour of the catalyst molded body.

[0016] Preferably, the radius of the first circumscribing circle of the outer contour of the catalyst molded body is 2 mm to 5 mm.

[0017] Preferably, the radius of the first circumscribing circle of the outer contour of the catalyst molded article is 3 mm to 4 mm.

[0018] Preferably, the catalyst molded body is packed into a reaction tube for catalytic use, and the ratio of the radius of the reaction tube to the radius of the first circumscribing circle is 2-7. [Effects of the Invention]

[0019] The catalyst shaped body provided by the present invention has a polygonal star-shaped catalyst particle profile with a circular arc-shaped first recess and an elliptical first corner. The first corner and the first recess have different geometric shapes. This design can reduce the contact area between catalyst particles so as to avoid the interlocking between the first corner and / or the first recess of the catalyst shaped body and the first recess and / or the first corner of an adjacent catalyst shaped body. This improves the porosity of the catalyst bed layer and reduces the packing ratio of the catalyst bed layer, thereby achieving the purpose of realizing the pressure drop of the catalyst bed layer.

[0020] The catalyst of the present invention preferably has a central through-hole, and the parameter design of the central through-hole effectively increases the outer surface area of ​​the catalyst particle and the strength of the particle, thereby further significantly improving the porosity of the catalyst bed layer and mitigating the increase in pressure drop of the bed layer in industrial equipment.

[0021] The central through-hole of the catalyst of the present invention preferably has a contour similar to the outer contour of the catalyst, which allows the wall thickness of the catalyst to be reduced, thus saving costs.

[0022] The packing density of the catalyst of the present invention is reduced, the catalytic performance is improved, the product yield per unit mass of the catalyst is increased, and the production capacity of the catalyst is improved.

[0023] The catalyst provided by the present invention has a cylindrical geometric body, and the catalyst molding has good mechanical properties, is easy to manufacture, can be molded under low pressure, has high mechanical strength and strong crush resistance, is free of irregular edges and corners, is easy to manufacture, has good wear resistance, is not easily broken, and has good mechanical stability, which can reduce the loss of the catalyst molding during transportation and use, ensure structural integrity during transportation, packing and high space velocity operation, and effectively reduce the increase in pressure drop in the catalyst bed layer caused by catalyst breakage and wear.

[0024] The above and other features and advantages of the present teachings will be readily apparent from the following detailed description of some of the best modes and other embodiments for carrying out the present teachings as defined in the appended claims, when taken in conjunction with the accompanying drawings. [Brief explanation of the drawings]

[0025] In order to more clearly explain the technical solutions of the present invention, the drawings necessary for describing the embodiments or prior art are briefly introduced below. The drawings described below are obviously some embodiments of the present invention. Those skilled in the art can obtain other drawings based on the drawings without any creative work.

[0026] [Figure 1] 1 is a schematic diagram of a perspective structure of the catalyst molded body described in a first embodiment of the present invention. FIG. [Figure 2] 2 is a cross-sectional schematic view of the catalyst molded body described in the first embodiment of the present invention. FIG. [Figure 3] 1 is a schematic diagram of a perspective structure of the catalyst molded body according to a second embodiment of the present invention. [Figure 4] FIG. 3 is a cross-sectional schematic view of the catalyst molded body described in the second embodiment of the present invention. [Figure 5] FIG. 10 is a schematic diagram of a perspective structure of a catalyst molded body according to a third embodiment of the present invention. [Figure 6] FIG. 3 is a cross-sectional schematic view of the catalyst molded body described in the third embodiment of the present invention. [Figure 7] FIG. 10 is a schematic diagram of a perspective structure of a catalyst molded body according to a fourth embodiment of the present invention. [Figure 8] FIG. 4 is a schematic cross-sectional view of the catalyst molded body described in the fourth embodiment of the present invention. [Figure 9] FIG. 10 is a schematic diagram of a perspective structure of a catalyst molded body according to a fifth embodiment of the present invention. [Figure 10] FIG. 10 is a schematic cross-sectional view of the catalyst molded body described in the fifth embodiment of the present invention. [Figure 11] FIG. 10 is a schematic diagram of a perspective structure of a catalyst molded body according to a sixth embodiment of the present invention. [Figure 12] FIG. 10 is a schematic cross-sectional view of the catalyst molded body described in the sixth embodiment of the present invention. [Figure 13] FIG. 10 is a schematic diagram of a perspective structure of a catalyst molded body according to a seventh embodiment of the present invention. [Figure 14] FIG. 10 is a schematic cross-sectional view of the catalyst molded body described in the seventh embodiment of the present invention. [Figure 15] FIG. 10 is a schematic diagram of a perspective structure of a catalyst molded body according to an eighth embodiment of the present invention. [Figure 16] FIG. 10 is a cross-sectional schematic view of the catalyst molded body described in the eighth embodiment of the present invention. [Figure 17] FIG. 13 is a schematic diagram of a perspective structure of a catalyst molded body according to a ninth embodiment of the present invention. [Figure 18] FIG. 12 is a cross-sectional schematic view of the catalyst molded body described in the ninth embodiment of the present invention.

[0027] The present disclosure is susceptible to various modifications and alternative forms, and several exemplary embodiments are shown by way of example in the drawings and described herein. However, the novel aspects of this disclosure are not limited to the specific forms illustrated in the above-listed drawings. Rather, the present disclosure covers modifications, equivalents, combinations, groups, and alternatives that are within the scope of the disclosure, for example, as encompassed by the appended claims. Additionally, the appended drawings are not necessarily to scale and may depict simplified representative examples of various preferred configurations of the present disclosure as disclosed herein. DETAILED DESCRIPTION OF THE INVENTION

[0028] Specific embodiments of the present invention will be described in detail below in conjunction with the drawings, but it should be understood that the scope of protection of the present invention is not limited by the specific embodiments. When referring to the appendix, the same reference numerals throughout the several drawings correspond to the same or similar components.

[0029] In order to make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. The described embodiments are not all embodiments of the present invention, but are a part of the embodiments. Based on the embodiments of the present invention, all other embodiments that can be obtained by those skilled in the art without creative work fall within the protection scope of the present invention.

[0030] The catalyst molded article of the present invention will be described below with reference to FIGS.

[0031] As shown in Figures 1 to 18, the catalyst molded body 100 provided by the present invention is a column body extending in the longitudinal direction, and the column body has a cross section perpendicular to the longitudinal direction. The column body is formed by sweeping the cross section perpendicular to the height direction / longitudinal direction in the height direction. The cross section has a central through-hole 1, at least four first corners 2, and the same number of first recesses 3 as the first corners 2.

[0032] The at least four first corners 2 are arranged at the same angular intervals along the circumferential direction so as to define a first circumscribing circle 101 of the outer contour of the catalyst molded body, each first corner 2 is tangent to the first circumscribing circle 101, and the at least four first corners 2 are rotationally symmetrical with respect to the center of the first circumscribing circle 101.

[0033] The first corners 2 and the first recesses 3 are alternately arranged in the circumferential direction and have different geometric shapes. Specifically, to avoid meshing between the first corners 2 and / or the first recesses 3 of the catalyst molded body and the first recesses 3 and / or the first corners 2 of the adjacent catalyst molded body, the first corners 2 are outwardly convex portions of a first ellipse having a ratio of major axis to minor axis greater than 1.2, and the first recesses 3 are inwardly concave arcs tangent to two adjacent first corners 2.

[0034] One first recess 3 is connected between any two adjacent first corners 2, and the first recess 3 is an inward concave arc tangent to the two adjacent first corners 2, and the central through hole 1 is concentric with the first circumscribing circle 101 of the cross section.

[0035] In this embodiment, the catalyst molded body 100 is a column body formed by sweeping the cross section along the height direction. Since the cross section has a central through-hole 1, at least four first corners 2, and at least four first recesses 3, the catalyst molded body 100 also has a central through-hole 1, at least four first corners 2, and at least four first recesses 3. The at least four first corners 2 are arranged circumferentially spaced apart along the first circumscribing circle 101, and each first corner 2 is tangent to the first circumscribing circle 101, so that the geometric body of the catalyst molded body 100 surrounded by the at least four first corners 2 is a cylinder. At the same time, the at least four first corners 2 are rotationally symmetric with respect to the center of the first circumscribing circle 101, i.e., each first corner 2 can be rotated around the center of the first circumscribing circle 101 to coincide with any one of the first corners 2, and therefore each first corner 2 is a part of a first ellipse of the same shape and size. The first recesses 3 are tangentially connected between every two first corners 2, and the first recesses 3, which are inwardly concave arcs, form an arc-shaped open flow channel on the outside of the catalyst molded body 100, and the central through-hole 1 forms an open flow channel on the inside of the catalyst molded body 100.

[0036] When preparing the catalyst molded body 100 of the present invention, a molding die is manufactured according to the shape of the catalyst molded body 100 of the present invention, and then the catalyst matrix powder or carrier is mixed and placed in the molding die, and compression molding is performed, so that catalyst particles having the shape of the catalyst molded body 100 of the present invention can be obtained, and the preparation is simple.

[0037] The catalyst molded body 100 of the present invention is suitable for being packed into a fixed bed reactor for catalytic applications. For example, the fixed bed reactor can be an industrial tubular reactor.

[0038] The catalyst molding 100 of the present invention forms a polygonal star-shaped catalyst particle profile by providing the central through hole 1, the first corner 2, and the first recess 3, which effectively increases the outer surface area of ​​the catalyst particle and significantly improves the porosity of the catalyst bed layer, thereby facilitating the mitigation of the increase in the pressure drop of the catalyst bed layer in industrial manufacturing equipment, reducing the pressure drop of the catalyst in the catalyst bed layer under high space velocity operation in the reactor, improving the reaction efficiency of the catalyst, increasing the duration of catalytic activity, effectively extending the operating cycle of the catalyst, reducing the packing density of the catalyst, improving catalyst performance, increasing the product yield per unit mass of the catalyst, and improving the production capacity of the catalyst. At the same time, the geometric body is cylindrical, so that the catalyst shaped body 100 has good mechanical properties, is easy to manufacture, can be formed under low pressing or extrusion pressure, has high mechanical strength, and is highly crush-resistant. By providing the first corner 2 as an ellipse and the first recess 3 as an inward-facing concave arc, the catalyst shaped body 100 does not have irregular edges and corners, is easy to manufacture, is not easily broken, has good wear resistance, is not easily worn, has good mechanical stability, reduces loss of the catalyst shaped body 100 during transportation and use, and can ensure structural integrity during transportation, packing, and high space velocity operation, effectively reducing the increase in pressure drop in the catalyst bed layer caused by catalyst breakage and wear. This solves the shortcomings of the prior art, such as the difficulty of manufacturing and shaping irregular-shaped catalyst bodies, poor crush resistance, and poor wear resistance, and the difficulty of ensuring structural integrity during catalyst transportation, packing, and high space velocity operation.

[0039] As shown in Figures 1 to 6, in some embodiments, the number of first corners 2 is four, the number of first recesses 3 is also four, and the catalyst molding 100 constitutes a four-cornered star-shaped catalyst particle.

[0040] As shown in Figures 7 to 12, in another embodiment, the number of first corners 2 is five, the number of first recesses 3 is five, and the catalyst molding 100 constitutes a five-cornered star-shaped catalyst particle.

[0041] As shown in Figures 13 to 18, in yet another embodiment, the number of first corners 2 is six, the number of first recesses 3 is six, and the catalyst molding 100 forms a hexagonal star-shaped catalyst particle.

[0042] Specifically, the height of the catalyst molded article 100 is equal to or greater than the radius of the first circumscribing circle 101 .

[0043] In this embodiment, the geometric size of the catalyst shaped body 100 is an important factor affecting the catalyst packing ratio and mass and heat transfer. By making the height of the catalyst shaped body 100 equal to or greater than the radius of the first circumscribing circle 101, the catalyst can have a lower packing density, which is favorable for improving the catalyst performance and the manufacturability of the catalyst.

[0044] More specifically, the radius of the first circumscribing circle 101 of the cross section of the catalyst molded article 100 is 2 mm to 5 mm.

[0045] In this embodiment, the diameter of the reaction tube for the oxidation reaction is generally 20 to 30 mm. By setting the radius of the first circumscribing circle 101 of the cross section of the catalyst molded body 100 to be 2 mm to 5 mm, the geometric size of the catalyst molded body 100 becomes more preferable, the packing density of the catalyst becomes more preferable, the catalyst performance is improved, and the product yield per unit mass of the catalyst is increased.

[0046] Preferably, the radius of the first circumscribing circle 101 of the cross section of the catalyst molded article 100 is 3 mm to 4 mm.

[0047] More specifically, the height of the catalyst molded article 100 is 3 mm to 10 mm.

[0048] In this embodiment, the diameter of the reaction tube for the oxidation reaction is generally 20 to 30 mm. By setting the height of the catalyst molded body 100 to be 3 to 10 mm, the catalyst molded body 100 has a more preferable geometric size and the packing density of the catalyst becomes more preferable, which is beneficial to improving the catalyst performance and further increasing the product yield per unit mass of the catalyst.

[0049] Preferably, the height of the catalyst molded article 100 is 4 mm to 7 mm.

[0050] Specifically, the angle between the lines connecting any two adjacent first corners 2 and the center of the first circumscribing circle 101 is 5° to 90°.

[0051] In this embodiment, the at least four first corners 2 are distributed at a certain circumferential interval angle along the first circumscribing circle 101. The positions of the first corners 2 are defined by the interval angle between the first corners 2. A specific interval angle is set according to the number of the first corners 2, and the interval angle between any two adjacent first corners 2 is 5° to 90°, which avoids concentrating the first corners 2 of the catalyst molded body 100, which is beneficial for reducing the pressure drop in the catalyst bed layer and improving the reaction efficiency of the catalyst.

[0052] In some embodiments, the at least four first corners 2 are arranged at equal angular intervals in the circumferential direction along the first circumscribing circle 101 of the cross section.

[0053] In this embodiment, by arranging the first corner 2 so that it is uniformly arranged in the circumferential direction along the first circumscribing circle 101, gas flows more uniformly, the reaction efficiency of the catalyst is higher, the catalyst molding 100 is subjected to uniform force in all directions and is not easily worn, which is beneficial to improving the crushing resistance of the catalyst molding 100, and the catalyst molding has more preferable mechanical stability, reduces the loss of the catalyst molding 100 during transportation and use, and reduces the increase in pressure drop of the catalyst bed layer caused by catalyst damage and wear.

[0054] The catalyst shaped body provided by the present invention has a polygonal star-shaped catalyst particle profile with an arc-shaped first recess and an elliptical first corner. The first corner and the first recess have different geometric shapes. This design avoids the interlocking between the first corner and / or the first recess of the catalyst shaped body and the first recess and / or the first corner of an adjacent catalyst shaped body. This reduces the contact area between the catalyst particles, improves the porosity of the catalyst bed layer, and reduces the packing ratio of the catalyst bed layer, thereby achieving the objective of realizing the pressure drop in the catalyst bed layer.

[0055] In some embodiments, a line connecting the center of the first ellipse of the first corner 2 and the center of the first circumscribing circle 101 is perpendicular to the major axis of the first ellipse of the first corner 2, and the ratio of the length of the major axis of the first ellipse of the first corner 2 to the radius of the first circumscribing circle 101 is 0.2 to 1.

[0056] The first ellipse of the first corner 2 is shown in dotted lines in the drawing.

[0057] In this embodiment, the first corner 2 of the catalyst molding 100 is a first ellipse, that is, the shape of the first corner 2 protruding from the first recess 3 on both sides is the outward convex part of the first ellipse. By setting the elliptical first corner 2 and the ratio of the length of the major axis of the first ellipse of the first corner 2 to the radius of the first circumscribed circle 101 to be 0.2 to 1, the porosity of the catalyst bed layer can be increased, the pressure drop of the catalyst in the reactor bed layer can be reduced, and the production capacity of the catalyst can be improved. At the same time, irregular edges and corners can be avoided, and the wear damage during transportation and use is less likely to occur, and the crushing resistance is improved, which is favorable to ensuring structural integrity, effectively reducing the pressure drop of the catalyst bed layer, and the structure is simple and easy to manufacture.

[0058] Specifically, as shown in Figures 1 to 18, the central through hole 1 is one of a circular through hole, an elliptical through hole, a polygonal through hole, and a polygonal star-shaped through hole having a shape similar to the cross section.

[0059] In this embodiment, the central through-hole 1 has a variety of selectable cross-sectional shapes, and the appropriate shape of the central through-hole 1 can be selected according to the porosity requirements and mechanical strength requirements, so as to meet more application scenario requirements and be more convenient and flexible to use.

[0060] For example, as shown in FIGS. 1, 2, 7, 8, 13 and 14, the central through-hole 1 is a circular through-hole.

[0061] As shown in Figures 3, 4, 9, 10, 15 and 16, the central through hole 1 is an elliptical through hole, and the long axis of the elliptical through hole is perpendicular to the axis of symmetry of the catalyst molded body 100.

[0062] As shown in Figures 5, 6, 11, 12, 17 and 18, the central through hole 1 is a polygonal star-shaped through hole having a shape similar to the cross-section of the catalyst molding 100, where "similar" means that the contour of the polygonal star-shaped through hole is roughly the same as the outer contour of the cross-section of the catalyst molding 100, i.e., the polygonal star-shaped through hole has a plurality of inner corners that are the same number as the first corners 2 and arranged in one-to-one correspondence, and also has a plurality of arc-shaped side portions that are the same number as the first recesses 3 and arranged in one-to-one correspondence.

[0063] As shown in FIG. 6 , the central through hole 1 has second corners 202 in the same number as the first corners 2 and second recesses 203 in the same number as the first recesses 3, the second corners define a second circumscribing circle 201 of the central through hole 1, the first corners 2 and the second corners 202 are aligned in the circumferential direction, the first recesses 3 and the second recesses 203 are aligned in the circumscribing direction, each second corner 202 is an outwardly convex portion of a second ellipse, each second corner 202 is tangent to the second circumscribing circle 201, and the second corners 202 are rotationally symmetrical with respect to the center of the second circumscribing circle 201, and the second recesses 203 are inwardly concave arcs tangent to two adjacent second corners 202.

[0064] Preferably, the ratio of the major axis to the minor axis of the second ellipse is equal to the ratio of the major axis to the minor axis of the first ellipse.

[0065] Preferably, the ratio of the area of ​​the second circumscribing circle of the central through-hole 1 to the area of ​​the first circumscribing circle of the outer contour of the catalyst molded article is 0.17 to 0.34.

[0066] Furthermore, the central through hole 1 may be a polygonal through hole, the number of vertices of the polygonal through hole being the same as the number of the first corners 2 of the catalyst molding 100, the number of sides being the same as the number of the first recesses 3, and the sides of the polygonal through hole being arranged in one-to-one correspondence with the first recesses 3.

[0067] Specifically, the ratio of the inner diameter of the central through hole 1 to the radius of the first circumscribing circle 101 is 0.2 to 1. When the central through hole 1 is a circular through hole, the inner diameter of the central through hole 1 is the radius of the circle, and when the central through hole 1 is an elliptical through hole, the inner diameter of the central through hole 1 is the length of the minor axis of the ellipse.

[0068] In this embodiment, by setting the ratio of the inner diameter of the central through hole 1 to the radius of the first circumscribing circle 101 to be 0.2 to 1, the catalyst molding 100 has a higher porosity, which reduces the pressure drop in the catalyst bed layer and improves the production capacity of the catalyst, and at the same time ensures that the catalyst molding 100 has sufficient mechanical strength and strong crushing resistance, and ensures the structural integrity during catalyst transportation, filling, and high space velocity operation, thereby effectively reducing the pressure drop.

[0069] Specifically, as shown in Figures 1 to 18, each first recess 3 is tangent to the first inscribed circle 102, the first ellipse corresponding to each first corner 2 is tangent to the second inscribed circle 103, the first inscribed circle 102 and the second inscribed circle 103 are both concentric with the first circumscribed circle 101, and the radius of the first inscribed circle 102 is larger than the radius of the second inscribed circle 103.

[0070] In this embodiment, by setting the radius of the first inscribed circle 102 to be larger than the radius of the second inscribed circle 103, the degree of inward concavity of the first recess 3 can be limited so as to avoid the first recess 3 being too recessed and making the first corner portion 2 excessively convex, which would affect the mechanical strength of the catalyst molding 100, thereby improving the mechanical stability, ensuring the crushing resistance of the catalyst molding 100, and reducing the increase in the pressure drop in the catalyst bed layer caused by catalyst damage and wear.

[0071] In this embodiment, the catalyst molding 100 has a certain crushing resistance, and the lateral crushing strength is greater than 20 N / particle, i.e., the maximum crushing pressure of each catalyst particle is greater than 20 N, and the catalyst molding has good mechanical stability and strong crushing resistance, which effectively ensures the structural integrity of the catalyst and effectively reduces the pressure drop.

[0072] The catalyst of the present invention preferably has a central through-hole, and the parameter design of the central through-hole effectively increases the outer surface area of ​​the catalyst particle and the strength of the particle, further significantly improving the porosity of the catalyst bed layer and mitigating the increase in pressure drop of the bed layer in industrial equipment.

[0073] The central through-hole of the catalyst of the present invention preferably has a contour similar to the outer contour of the catalyst, which allows the wall thickness of the catalyst to be reduced, thus saving costs.

[0074] The packing density of the catalyst of the present invention is reduced, the catalytic performance is improved, the product yield per unit mass of the catalyst is increased, and the production capacity of the catalyst is improved.

[0075] The geometric body of the catalyst provided by the present invention is cylindrical, and the catalyst shaped body has good mechanical properties, is easy to manufacture, can be molded under low pressure, has high mechanical strength and strong crush resistance, is free of irregular edges and corners, is easy to manufacture, has good wear resistance, is not easily broken, and has good mechanical stability, which can reduce the loss of the catalyst shaped body during transportation and use, ensure structural integrity during transportation, packing and high space velocity operation, and effectively reduce the increase in pressure drop in the catalyst bed layer caused by catalyst breakage and wear.

[0076] The catalyst molded body 100 of the present invention will be further described below using a four-cornered star-shaped low pressure drop vanadium phosphorus oxygen catalyst particle as a specific example.

[0077] The low pressure drop vanadium phosphorus oxygen catalyst particles are easy to prepare, and a matrix powder of the vanadium phosphorus oxygen catalyst or a mixture thereof with a carrier, a pore expander, or a lubricant is compression molded to obtain catalyst particle entities having the geometric shape of the catalyst molded body 100 described in the above embodiment, and the catalyst particles are mainly used for the selective oxidation of hydrocarbons, particularly for the production of maleic anhydride using the oxidation of alkanes.

[0078] The general process flow for preparing low pressure drop vanadium phosphorus oxygen catalyst particles is as follows.

[0079] A vanadium-containing compound is reacted with a phosphide in an organic reducing solution to produce a vanadium-phosphorus-oxygen catalyst matrix powder, which is shaped according to the geometric shape of the catalyst molded body 100 described in the above embodiment to form the catalyst molded body 100 after shaping, and then the catalyst molded body 100 can be converted into a finished catalyst after activation.

[0080] Maleic anhydride is an important organic chemical raw material widely used in the production of thermosetting resins, unsaturated polyester resins, pesticides, and fine chemicals, and is an important intermediate used in the synthesis of, for example, gamma-butyrolactone, tetrahydrofuran, and 1,4-butanediol. Currently, maleic anhydride is produced using cheap and readily available butane as a raw material. The process of producing maleic anhydride by oxidation of n-butane has the advantages of inexpensive raw materials, minimal environmental pollution, and low production costs. Vanadium phosphorus oxygen catalysts are the most effective catalysts for the production of maleic anhydride by the oxidation of n-butane, and research has shown that the shape of the vanadium phosphorus oxygen catalyst plays an important role in the catalytic oxidation of n-butane.

[0081] Low pressure drop vanadium phosphorus oxygen catalyst particles are used in the petrochemical industry in processes for preparing maleic anhydride by oxidation of hydrocarbons (n-butane) in fixed bed reactors or for preparing acrylic acid by condensation of acetic acid and formaldehyde.

[0082] According to the Elgin formula, the pressure drop value is

number

[0083] where P is the pressure,

number

[0084] The change in catalyst shape is due to the change in the catalyst equivalent diameter (d s ) and the porosity (ε B ) will affect the change in pressure drop. In the case of a fixed bed reactor, the catalyst must have sufficient lateral crush strength and natural packing crush resistance; otherwise, the catalyst will be damaged by factors such as vibration and force during use, and the generated dust will reduce the porosity of the catalyst bed layer and increase the pressure drop. The lateral crush strength of the catalyst according to the present invention is increased, and the natural packing crush strength remains unchanged, thereby reducing the pressure drop.

[0085] As shown in FIGS. 1 and 2, a first example of the four-cornered star-shaped low pressure drop vanadium phosphorus oxygen catalyst particles is obtained by molding according to the geometric shape of the catalyst molding 100 of the above embodiment.

[0086] The four-cornered star-shaped low pressure drop vanadium phosphorus oxygen catalyst particle of the first embodiment has four first corners 2, the geometric body surrounded by the four first corners 2 is a cylinder, and the radius of the cylinder is adjusted to be 3 mm, i.e., the radius of the first circumscribing circle 101 of the cross section is 3 mm, and the height of the cylinder is 6 mm.

[0087] The four first corners 2 are outwardly convex portions of the first ellipse tangent to the first circumscribing circle 101, and the four outwardly convex elliptical portions have the same major axis length and minor axis length, where the major axis length is 2 mm and the minor axis length is 1.2 mm. The interval angle between every two adjacent first corners 2 is 90°.

[0088] The four-cornered star-shaped low pressure drop vanadium phosphorus oxygen catalyst particle is continuously open and has a circular central through-hole 1 extending parallel to the axis of the cylinder, the diameter of the central through-hole 1 being 2 mm.

[0089] As shown in Figures 3 and 4, a second example of a four-cornered star-shaped low pressure drop vanadium phosphorus oxygen catalyst particle is obtained by molding according to the geometric shape of the catalyst molding 100 of the above embodiment.

[0090] The four cornered star-shaped low pressure drop vanadium phosphorus oxygen catalyst particles of the second embodiment differ from the four cornered star-shaped low pressure drop vanadium phosphorus oxygen catalyst particles of the first embodiment in that the central through-hole 1 is elliptical, the length of the major axis of the central through-hole 1 is 2 mm, and the length of the minor axis is 1.6 mm.

[0091] As shown in FIGS. 5 and 6, a third example of the four-cornered star-shaped low pressure drop vanadium phosphorus oxygen catalyst particles can be obtained by molding according to the geometric shape of the catalyst molding 100 of the above embodiment.

[0092] The difference between the first and second embodiments is that the four-cornered star-shaped low pressure drop vanadium phosphorus oxygen catalyst particle of the third embodiment has a central through-hole 1 similar to the outer contour of the cross section, and the ratio of the major axis to the minor axis of the second ellipse is equal to the ratio of the major axis to the minor axis of the first ellipse. The wall thickness of the low pressure drop vanadium phosphorus oxygen catalyst particle is controlled to be 2.5 mm.

[0093] The fourth embodiment is a four-cornered star-shaped low pressure drop vanadium phosphorus oxygen catalyst particle with the same shape as the first embodiment, except that the radius of the cylinder is adjusted to be 5.5 mm, i.e., the radius of the first circumscribing circle 101 of the cross section is 5.5 mm.

[0094] To highlight the effects of the present invention, Comparative Example 1, Comparative Example 2 and Comparative Example 3 are described.

[0095] Comparative Example 1 is a (hollow cylindrical) Raschig ring vanadium phosphorus oxygen catalyst particle having a diameter of 5.5 mm, a hole diameter of 2.5 mm, and a height of 5.5 mm.

[0096] Comparative Example 2 and Comparative Example 3 are catalysts related to China Patent Application Publication No. 102784666. The parameters of Comparative Example 2 and Comparative Example 3 are shown in Table 1 below.

[0097] [Table 1] where H is the height, R is the radius of the circumscribing circle, r is the radius of the inscribing circle, N is the number of outwardly convex circles in the outer contour, α is the radius of the outwardly convex circles, and Φ is the diameter of the central hole.

[0098] The vanadium phosphorus oxygen catalyst particles of Examples 1 to 4 and Comparative Examples 1, 2, and 3 were molded and activated to obtain finished vanadium phosphorus oxygen catalysts. First, the physical properties of the finished catalysts were measured to determine the specific surface area, hole volume, and crush strength of the finished catalysts. The results are shown in Table 2 below.

[0099] [Table 2] As can be seen from the table, the first to fourth examples using the profile of the catalyst molded body 100 of the present invention have a larger specific surface area and a larger hole volume than Comparative Examples 1, 2, and 3. Compared to Comparative Example 1, the catalyst crush strength is significantly increased and the crush resistance is stronger, thereby reducing the loss of the catalyst molded body 100 during transportation and use, ensuring the structural integrity during transportation, packing, and high space velocity operation, and effectively reducing the increase in pressure drop in the catalyst bed layer caused by catalyst breakage and wear.

[0100] Next, the catalyst particles of the first to fourth examples and comparative examples 1, 2 and 3 were each introduced into a 5.5 m long tubular fixed bed reactor having an inner diameter of 21 mm together with a 1.5 v% n-butane / air mixed gas, and evaluation was carried out under the same pressure and space velocity conditions. After the equipment had been operated stably for two hours, the composition of the reaction product was analyzed by gas chromatography of the reaction product.

[0101] Reactor inlet pressure of 0.15 MPa and 1600 h -1 The results of the measurements under test conditions of space velocity are shown in Table 3 below.

[0102] [Table 3] As can be seen from the table, compared with Comparative Examples 1, 2, and 3, the first to fourth examples using the profile of the catalyst molded body 100 of the present invention have significantly lower catalyst packing ratios and significantly reduced catalyst bed pressure drops. Furthermore, in the fourth example, the first circumscribed circle 101 of the cross section of the catalyst molded body is too large, resulting in an excessively low catalyst packing ratio and an excessively high linear velocity of the reactants, which also affects the reaction efficiency. The salt bath temperature required to achieve the same reaction efficiency is relatively high. Therefore, compared with Comparative Examples 1, 2, and 3, the first to fourth examples using the profile of the catalyst molded body 100 of the present invention have improved catalyst performance, and the yield of maleic anhydride per unit mass of catalyst increased at a lower salt bath temperature.

[0103] Reactor inlet pressure of 0.15 MPa and 2000 h -1 The results of measurements under test conditions of space velocity are shown in Table 4 below.

[0104] [Table 4] As can be seen from the table, compared to Comparative Examples 1, 2 and 3, the catalytic performance of the first to fourth examples using the catalyst molding 100 of the present invention was improved, and the yield of maleic anhydride per unit mass of catalyst increased at low salt bath temperatures.

[0105] Thus, in the present invention, since the first corner and the first recess have different geometric shapes, this design can reduce the contact area between the catalyst particles so as to avoid the interlocking between the first corner and / or the first recess of the catalyst molded body and the first recess and / or the first corner of the adjacent catalyst molded body, thereby improving the porosity of the bed layer and reducing the packing ratio of the catalyst bed layer, thereby achieving the purpose of realizing the pressure drop in the catalyst bed layer.

[0106] The detailed description and drawings or diagrams support and describe the present teachings, the scope of which is defined solely by the claims. Although some of the best modes and alternative embodiments for carrying out the present teachings have been described in detail, there are various alternative designs and embodiments for implementing the present teachings as defined in the appended claims. [Explanation of symbols]

[0107] 100 Catalyst molding 101 First circumscribed circle 102 First inscribed circle 103 Second inscribed circle 1 center through hole 2 First corner 3 First recess 201 Second circumscribed circle 202 Second Corner 203 Second Recess

Claims

1. A catalyst molded body, a columnar body extending in a longitudinal direction, the columnar body having a cross section perpendicular to the longitudinal direction; The cross section has a central through hole, at least four first corners (2), and the same number of first recesses (3) as the first corners; the at least four first corners are arranged at equal angular intervals along a circumferential direction so as to define a first circumscribing circle of an outer contour of the catalyst molded body, each first corner is tangent to the first circumscribing circle, and the at least four first corners are rotationally symmetrical with respect to a center of the first circumscribing circle; The first corners (2) and the first recesses (3) are arranged alternately in the circumferential direction, and have different geometric shapes from the first corners (2) and the first recesses (3) to avoid meshing between the first corners (2) and / or the first recesses (3) of the catalyst molding and the first recesses (3) and / or the first corners (2) of an adjacent catalyst molding, wherein the first corners (2) are outwardly convex portions of a first ellipse having a ratio of the major axis to the minor axis greater than 1.2, and the first recesses (3) are inwardly concave arcs tangent to two adjacent first corners (2).

2. The catalyst molded body of claim 1, characterized in that a line connecting the center of the first ellipse and the center of the first circumscribing circle is perpendicular to the major axis of the first ellipse, and the ratio of the length of the major axis of the first ellipse to the radius of the first circumscribing circle is 0.2 to 1.

3. 3. The catalyst molded body according to claim 2, characterized in that the central through hole has the same number of second corners as the first corners and the same number of second recesses as the first recesses, the second corners define a second circumscribing circle of the central through hole, the first corners and the second corners are aligned in the circumscribing direction, each second corner is tangent to the second circumscribing circle and the second corners are rotationally symmetrical with respect to the center of the second circumscribing circle, the first recesses and the second recesses are aligned in the circumscribing direction, each second corner is an outwardly convex portion of a second ellipse, and the second recess is an inwardly concave arc tangent to two adjacent second corners.

4. 4. The catalyst molded body according to claim 3, wherein the ratio of the major axis to the minor axis of the second ellipse is equal to the ratio of the major axis to the minor axis of the first ellipse.

5. The catalyst molding of claim 4, characterized in that the ratio of the area of ​​the second circumscribing circle of the central through hole to the area of ​​the first circumscribing circle of the outer contour of the catalyst molding is 0.17 to 0.

34.

6. 2. The catalyst molded body according to claim 1, characterized in that each first recess is tangent to a first inscribed circle, the first ellipse corresponding to each first corner is tangent to a second inscribed circle, the first inscribed circle and the second inscribed circle are both concentric with the first circumscribed circle, and the radius of the first inscribed circle is larger than the radius of the second inscribed circle.

7. 7. The catalyst molded body according to claim 1, wherein the height of the catalyst molded body in the longitudinal direction is equal to or greater than the radius of the first circumscribing circle of the outer contour of the catalyst molded body.

8. 8. The catalyst molded body according to claim 7, wherein the radius of the first circumscribing circle of the outer contour of the catalyst molded body is 2 mm to 5 mm.

9. 9. The catalyst molded body according to claim 8, wherein the radius of the first circumscribing circle of the outer contour of the catalyst molded body is 3 mm to 4 mm.

10. The catalyst molded body according to any one of claims 1 to 6, characterized in that the catalyst molded body is filled in a reaction tube for catalytic use, and a ratio of a radius of the reaction tube to a radius of the first circumscribing circle is 2 to 7.

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