CN219879943U

CN219879943U - Round corner catalyst formed body

Info

Publication number: CN219879943U
Application number: CN202223385912.4U
Authority: CN
Inventors: 张霞; 勾连科; 王海波; 李澜鹏
Original assignee: Sinopec Dalian Petrochemical Research Institute Co ltd; China Petroleum and Chemical Corp
Current assignee: Sinopec Dalian Petrochemical Research Institute Co ltd; China Petroleum and Chemical Corp
Priority date: 2022-12-16
Filing date: 2022-12-16
Publication date: 2023-10-24
Anticipated expiration: 2032-12-16

Abstract

The utility model relates to the technical field of catalysts, and provides a round-corner catalyst forming body, wherein the round-corner catalyst forming body is a column body with a height, and the column body is formed by sweeping a cross section perpendicular to the height direction; the cross section has a central through hole, at least four corners and at least four recesses; at least four corners are arranged at intervals along the circumscribed circumference of the cross section, the corners are outwards convex semicircles, each corner is tangential to the circumscribed circle, and the at least four corners are rotationally symmetrical relative to the center of the circumscribed circle; a concave part is connected between any two adjacent corners, and the concave part is a concave arc tangent to the two adjacent corners; the central through hole is concentric with the circumscribed circle. The catalyst forming body of the utility model forms a polygonal star-shaped catalyst structure with a central through hole, the geometric matrix is a cylinder, the catalyst forming body is easy to produce and form, is not easy to fall into corners, has good wear resistance, high mechanical strength and strong crushing resistance, can ensure structural integrity and reduce pressure drop in the transportation, filling and high airspeed operation processes.

Description

Round corner catalyst formed body

Technical Field

The utility model relates to the technical field of catalysts, in particular to a round corner catalyst forming body.

Background

The catalyst is usually prepared into a catalyst body and then is filled in a reactor for catalytic use, and the catalyst is prepared into different appearances to influence the service performance of the catalyst. The appearance of the traditional catalyst is cylindrical, raschig ring-shaped, clover-shaped, tooth-shaped, bird nest-shaped and the like, so that the requirements of industrial production on the specific surface area, pore volume, strength, pressure drop, mass transfer efficiency, hydrodynamics and the like of the catalyst can be met.

Most of the catalysts currently in common use in industry are cylindrical or hollow cylindrical catalysts. However, the cylindrical catalyst particles have channeling and wall flow phenomena, the gas is not uniform when passing, the reaction efficiency is affected, the external surface area is small, and the productivity of the catalyst is low; meanwhile, the resistance of the cylindrical catalyst particles is greatly reduced, and a large energy consumption load is caused to production equipment.

In recent years, the heteromorphism of catalyst particles has been developed to increase the porosity in the catalyst bed by a heteromorphic structure to reduce the pressure drop of the catalyst in the reactor bed and to increase the productivity of the catalyst.

However, the existing special-shaped catalyst body is complex in structure, difficult to produce and shape, irregular edges and corners are easy to abrade and fall in the transportation and use processes, low in mechanical strength, poor in crushing resistance and abrasion resistance, structural integrity is difficult to ensure in the catalyst transportation, filling and high-airspeed operation processes, and the catalyst is crushed and abraded to further increase pressure drop in a catalyst bed layer, so that energy consumption load of production equipment is increased.

Disclosure of Invention

The utility model provides a round corner catalyst forming body, which is used for solving the defects that the special-shaped catalyst body is difficult to produce and form, has poor crushing resistance and poor wear resistance and is difficult to ensure structural integrity in the processes of catalyst transportation, filling and high-space-velocity operation in the prior art.

The utility model provides a round-corner catalyst forming body, which is a column body with a height, wherein the column body is formed by sweeping a cross section perpendicular to the height direction;

wherein the cross section has a central through hole, at least four corners and at least four recesses;

the at least four corners are arranged at intervals along the circumscribed circumference of the cross section, the corners are convex semi-circles, each corner is tangential to the circumscribed circle, and the at least four corners are rotationally symmetrical relative to the center of the circumscribed circle;

one concave part is connected between any two adjacent corner parts, and the concave part is a concave arc tangent to the two adjacent corner parts;

the central through hole is concentric with the circumscribed circle.

According to the rounded catalyst shaped body provided by the utility model, the ratio of the diameter of the semicircle to the radius of the circumscribed circle is 0.2 to 1.

According to the rounded catalyst shaped body provided by the utility model, the at least four corners are equiangularly spaced along the circumscribed circumference.

According to the rounded catalyst molded body provided by the utility model, the central through hole is one of a circular through hole, an elliptical through hole, a polygonal through hole and a polygonal star-shaped through hole similar to the cross-sectional shape.

According to the rounded catalyst shaped body provided by the utility model, the ratio of the inner diameter of the central through hole to the radius of the circumscribed circle is 0.2 to 1.

According to the rounded catalyst forming body provided by the utility model, the number of the corners and the concave parts is greater than or equal to five, each concave part is tangential to a first inscribed circle, the circle corresponding to each corner is tangential to a second inscribed circle, the first inscribed circle and the second inscribed circle are concentric with the circumscribed circle, and the radius of the first inscribed circle is greater than that of the second inscribed circle.

According to the rounded catalyst shaped body provided by the utility model, the height of the rounded catalyst shaped body is larger than or equal to the radius of the circumscribed circle.

According to the rounded catalyst shaped body provided by the utility model, the radius of the circumscribed circle is 2 mm to 5 mm.

According to the rounded catalyst shaped body provided by the utility model, the radius of the circumscribed circle is 3 mm to 4 mm.

According to the rounded catalyst shaped body provided by the utility model, the height of the rounded catalyst shaped body is 3 mm to 10 mm.

According to the rounded catalyst shaped body provided by the utility model, the height of the rounded catalyst shaped body is 4 mm to 7 mm.

According to the rounded catalyst shaped body provided by the utility model, the lateral compressive strength of the rounded catalyst shaped body is more than 20N/particle.

The rounded corner catalyst forming body provided by the utility model has the advantages that the central through hole, the corners and the concave parts are arranged to form a polygonal star-shaped catalyst particle structure with the central through hole, so that the external surface area of catalyst particles is effectively increased, the porosity in a catalyst bed is obviously improved, the rising of the pressure drop of the catalyst bed in an industrial production device is relieved, the pressure drop of the catalyst in the catalyst bed under the high-airspeed operation in a reactor is reduced, the reaction efficiency of the catalyst is improved, the duration of the catalyst activity is prolonged, the operation period of the catalyst is effectively prolonged, the bulk density of the catalyst is reduced, the catalyst performance is improved, the product yield of the catalyst per unit mass is increased, and the production capacity of the catalyst is improved; meanwhile, the geometric matrix is a cylinder, so that the catalyst formed body has good mechanical properties, is easy to manufacture, can be formed under low tabletting or pushing sheet pressure, has high mechanical strength and strong crushing resistance, is provided with a semicircle at the corner, and a concave part is provided with a concave circular arc, so that the catalyst formed body has no irregular edge angle, is easy to produce, is not easy to fall off, has good wear resistance, is not easy to wear, has good mechanical stability, reduces the loss of the catalyst formed body in the transportation and use processes, can ensure the structural integrity in the transportation, filling and high airspeed operation processes, effectively reduces the increase of catalyst bed pressure drop caused by catalyst crushing and wear, and solves the defects that the special-shaped catalyst body in the prior art is difficult to produce and form, has poor crushing resistance and poor wear resistance, and is difficult to ensure the structural integrity in the transportation, filling and high airspeed operation processes of the catalyst.

Drawings

In order to more clearly illustrate the utility model or the technical solutions of the prior art, the following description will briefly explain the drawings used in the embodiments or the description of the prior art, and it is obvious that the drawings in the following description are some embodiments of the utility model, and other drawings can be obtained according to the drawings without inventive effort for a person skilled in the art.

FIG. 1 is a schematic perspective view of a rounded catalyst shaped body according to an embodiment of the present utility model;

FIG. 2 is a schematic cross-sectional view of a rounded catalyst shaped body provided in accordance with an embodiment of the present utility model;

FIG. 3 is a schematic perspective view of a rounded catalyst shaped body according to a second embodiment of the present utility model;

FIG. 4 is a schematic cross-sectional view of a rounded catalyst shaped body provided in accordance with a second embodiment of the utility model;

FIG. 5 is a schematic perspective view of a rounded catalyst shaped body provided in accordance with a third embodiment of the present utility model;

FIG. 6 is a schematic cross-sectional view of a rounded catalyst shaped body provided in accordance with a third embodiment of the utility model;

FIG. 7 is a schematic perspective view of a rounded catalyst shaped body according to a fourth embodiment of the present utility model;

FIG. 8 is a schematic cross-sectional view of a rounded catalyst shaped body provided in accordance with a fourth embodiment of the utility model;

FIG. 9 is a schematic perspective view of a rounded catalyst shaped body provided in accordance with a fifth embodiment of the present utility model;

FIG. 10 is a schematic cross-sectional view of a rounded catalyst shaped body provided in accordance with embodiment five of the utility model;

FIG. 11 is a schematic perspective view of a rounded catalyst shaped body according to a sixth embodiment of the present utility model;

FIG. 12 is a schematic cross-sectional view of a rounded catalyst shaped body provided in accordance with a sixth embodiment of the utility model;

FIG. 13 is a schematic perspective view of a rounded catalyst shaped body provided in accordance with an embodiment seven of the present utility model;

FIG. 14 is a schematic cross-sectional view of a rounded catalyst shaped body provided in accordance with embodiment seven of the present utility model;

FIG. 15 is a schematic perspective view of a rounded catalyst shaped body provided in accordance with an eighth embodiment of the present utility model;

FIG. 16 is a schematic cross-sectional view of a rounded catalyst shaped body provided in accordance with an embodiment eight of the utility model;

FIG. 17 is a schematic perspective view of a rounded catalyst shaped body provided in accordance with an embodiment ninth of the present utility model;

fig. 18 is a schematic cross-sectional view of a rounded catalyst shaped body provided in embodiment nine of the present utility model.

Reference numerals:

100: a rounded catalyst shaped body;

101: externally cutting a circle; 102: a first inscribed circle; 103: a second inscribed circle;

1: a central through hole: 2: a corner; 3: a recess.

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the present utility model more apparent, the technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings, and it is apparent that the described embodiments are some embodiments of the present utility model, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.

The rounded catalyst shapes of the present utility model are described below in conjunction with fig. 1-18.

As shown in fig. 1 to 18, the rounded catalyst molded body 100 provided in the present utility model is a cylinder having a height, which is formed by sweeping a cross section perpendicular to the height direction in the height direction. Wherein the cross section has a central through hole 1, at least four corners 2 and at least four recesses 3; the at least four corners 2 are circumferentially arranged at intervals along the circumscribed circle 101 of the cross section, the corners 2 are convex semi-circles, each corner 2 is tangential to the circumscribed circle 101 of the cross section, and the at least four corners 2 are rotationally symmetrical relative to the center of the circumscribed circle 101 of the cross section; a concave part 3 is connected between any two adjacent corner parts 2, and the concave part 3 is a concave arc tangent to the two adjacent corner parts 2; the central through hole 1 is concentric with the circumscribed circle 101 of the cross section.

In the present embodiment, the rounded catalyst shaped body 100 is a cylinder formed by sweeping a cross section in the height direction, and since the cross section has a central through hole 1, at least four corners 2, and at least four recesses 3, the rounded catalyst shaped body 100 also has a central through hole 1, at least four corners 2, and at least four recesses 3; by arranging the at least four corners 2 at intervals along the circumferential direction of the circumscribed circle 101, and each corner 2 is tangent to the circumscribed circle 101, the geometric matrix of the catalyst forming body 100 with round corners surrounded by the at least four corners 2 is a cylinder; meanwhile, the at least four corners 2 are rotationally symmetrical relative to the center of the circumscribed circle 101, that is, each corner 2 can rotate around the center of the circumscribed circle 101 to coincide with any one corner 2, so that each corner 2 is a semicircle with the same shape and size; the concave parts 3 are tangentially connected between every two corner parts 2, the concave circular-arc concave parts 3 form arc-shaped open flow passages on the outer side of the round-corner catalyst formed body 100, and the central through holes 1 form open flow passages on the inner side of the round-corner catalyst formed body 100.

When the rounded catalyst molded body 100 of the present utility model is prepared, a molding die is manufactured according to the shape of the rounded catalyst molded body 100 of the present utility model, and then catalyst matrix powder or carrier is mixed and then placed in the molding die to be pressed and molded, thus obtaining catalyst particles having the shape of the rounded catalyst molded body 100 of the present utility model, which is simple to manufacture.

The rounded catalyst shapes 100 of the present utility model are suitable for catalytic use packed in a fixed bed reactor, which may be, for example, an industrial tubular reactor.

The rounded catalyst forming body 100 of the utility model, through setting up the central through hole 1, corner 2 and recess 3, form the multiangle star-shaped catalyst particle configuration with central through hole 1, increase the external surface area of the catalyst particle effectively, the porosity in the catalyst bed is improved obviously, thus help to relieve the pressure drop rise of catalyst bed in the industrial production device, reduce the pressure drop in catalyst bed of catalyst under the high space velocity operation in the reactor, raise the reaction efficiency of the catalyst, the duration of catalyst activity increases, lengthen the operation cycle of the catalyst effectively, and the bulk density of the catalyst decreases, the catalyst performance promotes, the product yield of the catalyst of unit mass increases, raise the productivity of the catalyst; meanwhile, the geometric matrix is a cylinder, so that the round-corner catalyst formed body 100 has good mechanical properties, is easy to manufacture, can be formed under low tabletting or pushing pressure, has high mechanical strength and strong crushing resistance, is provided with a semicircle at the corner 2 and a concave part 3 which is a concave circular arc, the round-corner catalyst formed body 100 has no irregular edges and corners, is easy to produce, is not easy to fall off, is good in wear resistance, is good in mechanical stability, reduces the loss of the round-corner catalyst formed body 100 in the transportation and use processes, can ensure structural integrity in the transportation, filling and high-airspeed operation processes, effectively reduces the increase of catalyst bed pressure drop caused by catalyst crushing and wear, and solves the defects that the special-shaped catalyst body in the prior art is not easy to produce and form, has poor crushing resistance and wear resistance, and is difficult to ensure structural integrity in the transportation, filling and high-airspeed operation processes of the catalyst.

In some embodiments, as shown in fig. 1-6, the number of corners 2 is four, the number of recesses 3 is four, and the rounded catalyst shapes 100 constitute four-corner star-shaped catalyst particles.

In other embodiments, as shown in fig. 7 to 12, the number of corners 2 is five, the number of recesses 3 is five, and the rounded catalyst shapes 100 constitute pentagram-shaped catalyst particles.

In still other embodiments, as shown in fig. 13 to 18, the number of corners 2 is six, the number of recesses 3 is six, and the rounded catalyst shaped body 100 constitutes a hexagonal star-shaped catalyst particle.

Specifically, the height of the rounded catalyst formed body 100 is greater than or equal to the radius of the circumscribed circle 101.

In this embodiment, the geometry of the rounded catalyst shaped body 100 is a key factor affecting the catalyst loading ratio and mass and heat transfer, and by setting the height of the rounded catalyst shaped body 100 to be greater than or equal to the radius of the circumscribed circle 101, the catalyst can have a lower bulk density, which is beneficial to improving the catalyst performance and improving the catalyst productivity.

More specifically, the radius of the circumscribed circle 101 of the cross section of the rounded catalyst formed body 100 is 2 mm to 5 mm.

In this example, for the oxidation reaction, the diameter of the reaction tube is generally 20-30 mm, and by providing the radius of the circumscribed circle 101 of the cross section of the rounded catalyst formed body 100 to be 2-5 mm, the geometric dimension of the rounded catalyst formed body 100 is more excellent, the bulk density of the catalyst is better, the catalyst performance is improved, and the product yield per unit mass of the catalyst is increased.

Preferably, the radius of the circumscribed circle 101 of the cross section of the rounded catalyst shaped body 100 is 3 to 4 millimeters.

More specifically, the height of the rounded catalyst form 100 is 3 millimeters to 10 millimeters.

In this embodiment, for the oxidation reaction, the diameter of the reaction tube is generally 20-30 mm, and by providing the rounded catalyst forming body 100 with a height of 3-10 mm, the rounded catalyst forming body 100 has a better geometry, and the bulk density of the catalyst is better, which is beneficial to improving the catalyst performance and further increasing the product yield of the catalyst per unit mass.

Preferably, the height of the rounded catalyst form 100 is 4 to 7 millimeters.

Specifically, the included angle between the connecting line of the center of any two adjacent corners 2 and the center of the circumscribed circle 101 is 5 degrees to 90 degrees.

In this embodiment, the at least four corners 2 are distributed at intervals along the circumferential direction of the circumscribed circle 101, the positions of the corners 2 are defined by intervals between the corners 2, the specific intervals are set according to the number of the corners 2, and the intervals between any two adjacent corners 2 are 5 ° to 90 °, so that the corners 2 of the round corner catalyst formed body 100 are prevented from being distributed and concentrated, which is beneficial to reducing the pressure drop of the catalyst bed and improving the reaction efficiency of the catalyst.

In some embodiments, the at least four corners 2 are equally angularly spaced circumferentially along the circumscribed circle 101 of the cross-section.

In this embodiment, by arranging the corners 2 to be uniformly distributed along the circumferential direction of the circumscribed circle 101, the gas is more uniform when passing through, the reaction efficiency of the catalyst is higher, the stress of the rounded catalyst forming body 100 in all directions is uniform, the rounded catalyst forming body is not easy to wear, the crushing resistance of the rounded catalyst forming body 100 is improved, the mechanical stability is better, the loss of the catalyst forming body 100 in the transportation and use processes is reduced, and the increase of the pressure drop of the catalyst bed caused by the crushing and wear of the catalyst is reduced.

Specifically, the ratio of the diameter of the semicircle of the corner 2 to the radius of the circumscribed circle 101 is 0.2 to 1. The connection line between the center of the semicircle of the corner 2 and the center of the circumscribed circle 101 is perpendicular to the diameter of the semicircle of the corner 2, and the semicircle of the corner 2 is indicated by a dotted line in the figure.

In the present embodiment, the corner portions 2 of the rounded catalyst molded body 100 are semicircular, that is, the shape of the concave portions 3 of the corner portions 2 protruding from both sides is a semicircle, and the semicircle corresponding to the semicircle, that is, half of the circle can be completely overlapped with the semicircle; through setting up semicircular bight 2, and the ratio of the semicircular diameter of bight 2 and the radius of circumscribed circle 101 is 0.2 to 1, can improve the porosity in the catalyst bed, reduce the pressure drop of catalyst in the reactor bed, improve the throughput of catalyst, avoid appearing irregular edges and corners simultaneously, be difficult for wearing and tearing in transportation and use and fall the angle, improve crushing resistance, be favorable to guaranteeing structural integrity, effectively reduce the catalyst bed pressure drop, moreover simple structure, easy production shaping.

Specifically, as shown in fig. 1 to 18, the center 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 similar cross-sectional shape.

In this embodiment, the central through hole 1 has various selectable cross-sectional shapes, and a suitable shape of the central through hole 1 can be selected according to the requirements of porosity and mechanical strength, so as to meet the requirements of more application scenes, and the use is more convenient and flexible.

For example, as shown in fig. 1, 2, 7, 8, 13 and 14, the center through hole 1 is a circular through hole.

As shown in fig. 3, 4, 9, 10, 15 and 16, the central through hole 1 is an elliptical through hole, the long axis of which is perpendicular to the symmetry axis of the rounded catalyst compact 100.

The central through hole 1 may be a polygonal through hole, the number of vertices of which is the same as the number of corners 2 of the round catalyst molded body 100, the number of sides is the same as the number of concave portions 3, and the sides of the polygonal through hole are arranged opposite to the concave portions 3 in a one-to-one correspondence.

As shown in fig. 5, 6, 11, 12, 17 and 18, the central through hole 1 is a polygonal star-shaped through hole having a similar cross-sectional shape to the rounded catalyst formed body 100; wherein, the similar means that the outline of the polygonal star-shaped through hole is approximately the same as the external outline of the cross section of the round catalyst forming body 100, that is, the polygonal star-shaped through hole has a plurality of inner corners which are the same as the corners 2 in number and are arranged in a one-to-one correspondence manner, and also has a plurality of arc edges which are the same as the recesses 3 in number and are arranged in a one-to-one correspondence manner.

Specifically, the ratio of the inner diameter of the center through hole 1 to the radius of the circumscribed 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 a circular radius; when the central through hole 1 is an elliptical through hole, the inner diameter of the central through hole 1 is an elliptical short axial length.

In this embodiment, by setting the ratio of the inner diameter of the center through hole 1 to the radius of the circumscribed circle 101 to be 0.2 to 1, the rounded catalyst forming body 100 has higher porosity, reduces the pressure drop in the catalyst bed, improves the productivity of the catalyst, ensures that the rounded catalyst forming body 100 has sufficient mechanical strength, has strong crushing resistance, can ensure structural integrity during transportation, filling and high space velocity operation of the catalyst, and effectively reduces the pressure drop.

In some embodiments, as shown in fig. 8, 10, 12, 14, 16, and 18, the number of corners 2 and recesses 3 of the rounded catalyst shaped body 100 is greater than or equal to five, each recess 3 is tangent to a first inscribed circle 102, each corner 2 corresponds to a circle tangent to a second inscribed circle 103, the first inscribed circle 102, the second inscribed circle 103 are concentric with the circumscribed circle 101, and the radius of the first inscribed circle 102 is greater than the radius of the second inscribed circle 103.

In this embodiment, the radius of the first inscribed circle 102 is larger than the radius of the second inscribed circle 103, so that the concave degree of the concave portion 3 can be limited, the mechanical strength of the rounded catalyst molded body 100 is prevented from being influenced by excessive protrusion of the corner portion 2 due to excessive concave of the concave portion 3, the mechanical stability is better, the crush resistance of the rounded catalyst molded body 100 is ensured, and the increase of the catalyst bed pressure drop caused by catalyst breakage and abrasion is reduced.

Specifically, the lateral compressive strength of the rounded catalyst shaped body 100 is greater than 20N/particle.

In this embodiment, the rounded catalyst shaped body 100 has a certain compressive capacity, wherein the lateral compressive strength is greater than 20N/particle, i.e., the maximum crush resistance of each catalyst particle is greater than 20 newtons, the mechanical stability is good, the crush resistance is strong, the structural integrity of the catalyst is effectively ensured, and the pressure drop is effectively reduced.

The rounded catalyst shaped body 100 of the present utility model will be further described below with reference to a specific example of a four-corner star-shaped low pressure drop vanadium phosphorus oxide catalyst particle.

The low pressure drop vanadium phosphorus oxide catalyst particles are simple to manufacture, and the catalyst particle entity with the geometric shape of the round corner catalyst formed body 100 provided by the embodiment is obtained by compression molding after vanadium phosphorus oxide catalyst matrix powder or the mixture of the vanadium phosphorus oxide catalyst matrix powder and a carrier, a pore expanding agent or a lubricant is used for hydrocarbon selective oxidation, in particular for the production of maleic anhydride by alkane oxidation.

The preparation process of the low pressure drop vanadium phosphorus oxide catalyst particles is approximately as follows:

the vanadium-containing compound is reacted with phosphide in the organic reducing solvent to produce vanadium phosphorus oxygen catalyst matrix powder, the vanadium phosphorus oxygen catalyst matrix powder is molded according to the geometry of the rounded catalyst molded body 100 provided in the above embodiment, the rounded catalyst molded body 100 is formed after the molding, and then the rounded catalyst molded body 100 is activated to be converted into a finished catalyst.

Maleic anhydride, abbreviated as maleic anhydride, is an important organic chemical raw material for the production of thermosetting resins, unsaturated polyester resins, pesticides and fine chemical products in large quantities, such as important intermediates for the synthesis of gamma-butyrolactone, tetrahydrofuran and 1, 4-butanediol. At present, butane which is cheap and easy to obtain is used as a raw material to produce maleic anhydride, and the process for preparing maleic anhydride by using n-butane oxidation has the advantages of low raw material cost, little environmental pollution and low maleic anhydride production cost. The vanadium phosphorus oxide catalyst is the most effective catalyst for preparing maleic anhydride by n-butane oxidation, and researches show that the forming morphology of the vanadium phosphorus oxide catalyst plays a core important role in the catalytic oxidation of n-butane.

The low pressure drop vanadium phosphorus oxide catalyst particle is used in the process of preparing acrylic acid through oxidizing hydrocarbon (n-butane) to prepare maleic anhydride or condensing acetic acid with formaldehyde in fixed bed reactor in petrochemical industry.

As shown in fig. 1 and 2, the geometry of the rounded catalyst shaped body 100 according to the above embodiment is shaped to yield an embodiment one of the four-corner star-shaped low pressure drop vanadium phosphorus oxide catalyst particles.

The four-corner star-shaped low-pressure-drop vanadium phosphorus oxide catalyst particles in the first embodiment are provided with four corners 2, the geometric matrix enclosed by the four corners 2 is a cylinder, and the radius of the cylinder is measured to be 3.5 mm, namely, the radius of an circumscribed circle 101 of the cross section is 3.5 mm; the height of the cylinder is 6 mm.

The four corners 2 are all half circles tangential to the circumscribed circle 101, the four half circles having the same diameter of 2 mm. The spacing angle between every two adjacent corners 2 is 90 °.

The four-corner star-shaped low pressure drop vanadium phosphorus oxide catalyst particles have a continuously open circular central through hole 1 extending parallel to the cylinder axis, the diameter of the central through hole 1 being 2.5 mm.

As shown in fig. 3 and 4, the geometry of the rounded catalyst shaped body 100 according to the above embodiment is shaped to yield a second embodiment of the four-corner star-shaped low pressure drop vanadium phosphorus oxide catalyst particles.

The four-corner star-shaped low-pressure-drop vanadium phosphorus oxide catalyst particles of the second embodiment are different from those of the first embodiment in that the central through hole 1 is elliptical, the long axis of the central through hole 1 is 2.2 mm, and the short axis is 1.8 mm.

As shown in fig. 5 and 6, the geometry of the rounded catalyst shaped body 100 according to the above embodiment is shaped to give example three of the four-corner star-shaped low pressure drop vanadium phosphorus oxide catalyst particles.

The difference from the first and second embodiments is that the four-corner star-shaped low pressure drop vanadium phosphorus oxide catalyst particles of the third embodiment are characterized in that the central through hole 1 is quadrilateral or four-corner star-shaped similar to the cross section shape, and the wall thickness of the four-corner star-shaped low pressure drop vanadium phosphorus oxide catalyst particles is controlled to be 2.8 mm.

Meanwhile, comparative example 1 was set to be raschig ring-shaped (hollow cylindrical) vanadium phosphorus oxide catalyst particles having a diameter of 5.5 mm, a pore diameter of 2.5 mm, and a height of 5.5 mm; comparative example 2 is a four-corner star shaped low pressure drop vanadium phosphorus oxide catalyst particle similar in shape to example one, except that the radius of the cylinder is measured to be 5.5 mm, i.e., the radius of the circumscribed circle 101 of the cross section is 5.5 mm.

The vanadium phosphorus oxide catalyst particles according to examples one to three and comparative examples 1 to 2 were molded and activated to obtain the final vanadium phosphorus oxide catalyst. The physical properties of the finished catalyst were first measured to obtain the specific surface area, pore volume and compressive strength of the finished catalyst, and the results are shown in table 1 below:

	example 1	Example two	Example III	Comparative example 1	Comparative example 2
						Specific surface area (m) ² /g)	24.1	22.9	28.4	21.0	23.9
Pore volume (cm) ³ /g)	0.203	0.218	0.275	0.201	0.210
						Compressive strength (N)	25.9	24.6	32.6	22	35.7

It can be seen that examples one to three and comparative example 2 employing the rounded catalyst shaped body 100 configuration of the present utility model have an increased specific surface area, an increased pore volume, and most importantly, a significantly increased compressive strength of the catalyst, a stronger crush resistance, reduced loss of the catalyst shaped body 100 during transportation and use, ensured structural integrity during transportation, loading and high space velocity operation, and effectively reduced increase in catalyst bed pressure drop caused by catalyst breakage and attrition, as compared to comparative example 1 employing the conventional hollow cylindrical catalyst configuration.

Subsequently, the four-corner star-shaped low pressure drop vanadium phosphorus oxide catalyst particles of examples one to three and comparative example 2 and the hollow cylindrical catalyst particles of comparative example 1 were respectively charged into a 5.5 m long tube fixed bed reactor having an inner diameter of 21 mm, and 1.5v% of n-butane/air mixture was introduced, and evaluated under the same pressure and space velocity conditions; after the device is stably operated for 2 hours, the composition of the reaction product is analyzed by gas chromatography.

Wherein the reactor inlet pressure at 0.15MPa and the space velocity is 1600h ^-1 The measurement results are shown in table 2 below under the test conditions of (a):

	example 1	Example two	Example III	Comparative example 1	Comparative example 2
						Natural filling pile ratio (Kg/L)	0.48	0.53	0.50	0.70	0.43
Salt bath temperature (DEG C)	405	410	407	415	422
						Conversion (mol) ^-1 )	85.1	85.8	85.5	85.3	84.8
Selectivity of	70.2	68.6	69.5	68.2	64.9
						Resistance drop (KPa)	43.8	48.8	46.2	78.8	40.1

It can be seen that examples one to three and comparative example 2 employing the rounded catalyst form 100 configuration of the present utility model have significantly lower catalyst bulk ratios and significantly lower catalyst bed resistance drop compared to comparative example 1 employing the conventional hollow cylindrical catalyst configuration. In addition, in comparative example 2, since the circumscribed circle 101 of the cross section of the catalyst molded body is excessively large, the loading ratio of the catalyst is extremely low, the linear velocity of the reactant is excessively high, and thus the reaction efficiency is affected, and the salt bath temperature required to achieve the same reaction efficiency is relatively high, so that the catalyst performance is improved and the maleic anhydride yield per unit mass of catalyst is increased at a low salt bath temperature in examples one to three of the configuration of the catalyst molded body 100 of the present utility model as compared with comparative examples 1 and 2.

At a reactor inlet pressure of 0.15MPa and a space velocity of 2000h ^-1 The measurement results are shown in table 3 below under the test conditions of (a):

	example 1	Example two	Example III	Comparative example 1	Comparative example 2
						Natural filling pile ratio (Kg/L)	0.48	0.53	0.50	0.70	0.43
Salt bath temperature (DEG C)	408	414	412	417	424
						Conversion (mol) ^-1 )	82.9	84.2	83.5	82.3	83.9
Selectivity of	70.5	69.2	70.4	69.3	62.3
						Resistance drop (KPa)	62.6	68.5	65.1	96.5	44.3

It can be seen that examples one to three, which employ the configuration of the rounded catalyst shaped body 100 of the present utility model, have improved catalyst performance and increased maleic anhydride yield per unit mass of catalyst at low salt bath temperatures as compared to comparative examples 1 and 2.

Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present utility model, and are not limiting; although the utility model has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present utility model.

Claims

1. A rounded catalyst shaped body, characterized in that the rounded catalyst shaped body is a cylinder having a height, the cylinder being formed by a cross-sectional sweep perpendicular to the height direction;

the central through hole is concentric with the circumscribed circle.

2. The rounded catalyst shaped body according to claim 1, characterized in that the ratio of the diameter of the semicircle to the radius of the circumscribed circle is 0.2 to 1.

3. The rounded catalyst form of claim 1, wherein the at least four corners are equiangularly spaced apart along the circumscribed circumference.

4. The rounded catalyst shaped body as claimed in claim 1, wherein the central through hole 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-sectional shape.

5. The rounded catalyst shaped body according to claim 4, characterized in that the ratio of the inner diameter of the central through hole to the radius of the circumscribed circle is 0.2 to 1.

6. The rounded catalyst shaped body according to claim 1, wherein the number of corners and recesses is greater than or equal to five, each recess is tangent to a first inscribed circle, each corresponding circle of the corners is tangent to a second inscribed circle, the first inscribed circle, the second inscribed circle are concentric with the circumscribed circle, and the radius of the first inscribed circle is greater than the radius of the second inscribed circle.

7. The rounded catalyst shaped body according to any one of claims 1 to 6, characterized in that the height of the rounded catalyst shaped body is greater than or equal to the radius of the circumscribed circle.

8. The rounded catalyst shaped body according to claim 7, characterized in that the radius of the circumscribed circle is 2 to 5 millimeters.

9. The rounded catalyst shaped body according to claim 8, characterized in that the radius of the circumscribed circle is 3 to 4 millimeters.

10. The rounded catalyst shaped body according to claim 7, characterized in that the height of the rounded catalyst shaped body is 3 to 10 millimeters.

11. The rounded catalyst shaped body according to claim 10, characterized in that the height of the rounded catalyst shaped body is 4 to 7 millimeters.

12. The rounded catalyst shaped body according to any one of claims 1 to 6, characterized in that the lateral compressive strength of the rounded catalyst shaped body is greater than 20N/particle.