EA045132B1 - GAS DISTRIBUTION PLATE, FLUIDIFIER DEVICE AND METHOD OF CARRYING OUT THE REACTION - Google Patents

Description

Field of technology to which the present invention relates

The invention relates to a gas distribution plate and, in particular, to an air distribution plate. Moreover, the present invention relates to a fluidizing device comprising a gas distribution plate and its use in an oxidation method or an ammoxidation method.

BACKGROUND OF THE INVENTION

All over the world, acrylonitrile is produced by ammoxidation of propylene, and in its production method, there is a certain requirement for the ratio between the raw materials, for example, the ratio of ammonia and propylene is 1-1.5, and the ratio of air and propylene is 8.5-10.5. Essentially, this ratio is simply a range of explosive limits of a mixture of propylene and ammonia, and in the production method, the three starting materials are not introduced into the reaction layer after mixing, but are separately introduced into the layer, and the mixture of propylene and ammonia is introduced into the layer through one distributor, and air is introduced into the layer through another distributor. Propylene, ammonia and air take part in the ammoxidation reaction, preferably carried out under the action of a catalyst, so that the possibility of the source gas existing in a range of explosive concentrations can be prevented.

As illustrated in FIG. 1, in the fluidized bed ammoxidation reactor 1, the corresponding components are arranged in the following sequence: air inlet 8, gas distribution plate (also referred to as air distribution plate) 6, propylene-ammonia feed distributor 10, reactor wall 4, and heat sink 7. Air enters the reactor through the inlet 8, passes through the gas distribution plate 6, is evenly mixed with the initial gaseous mixture of propylene and ammonia entering the reactor through the initial mixture distributor 10, and then passes into the catalytic layer, so that the ammoxidation reaction can be carried out.

The gas distribution plate is one of the important internal components of an acrylonitrile fluidized bed reactor, and the design quality of the gas distribution plate has a direct impact on the fluidization quality of the fluidized bed and the process performance of the reactor. In acrylonitrile production, a typical gas distribution plate for a fluidized bed is present in the form of a perforated plate containing short pipes, and in particular, the gas distribution plate contains a solid metal plate and gas distribution plate nozzles. Air enters the nozzles through the holes at the ends of the nozzles and then enters the bed through the nozzles of the air distribution plate. The source gas and air are directed by each nozzle of the gas distribution plate and are dispersed in the layer from bottom to top.

In the case of an acrylonitrile producing fluidized bed reactor, the pressure drop of the gas distribution platen can be affected by changing the design of the gas distribution platen, and in order to ensure uniform distribution of the gas flow and prevent significant heterogeneity caused by a certain fluctuation or load reduction, generally the distributor must provide sufficient pressure drop .

In the paper, Study of Capacity Enhancement and Modification of an Acrylonitrile Plant (Contemporary Chemical Industry, Vol. 34, No. 5), it is described that the pressure drop of the gas distribution plate is approximately 60% of the bed pressure drop, which, according to the authors, leads to uniform gas distribution and velocity passage through the holes that is not so high as to cause significant erosion of the catalyst.

GB 1265770 A discloses a fluidized bed reactor in which the influence of the wall effect can be eliminated by fluidizing the catalyst located close to the reactor wall using a fluid through an annular distribution pipe, which occupies a position on the distribution plate close to the reactor wall and is concentric with distribution plate.

Brief Disclosure of the Present Invention

The authors of the present invention have found that as the scale of acrylonitrile production increases, the diameter of the reactor also increases, and if the pressure drop of the gas distribution plate described in the work Study on increasing the productivity and modification of an acrylonitrile production plant is used, the quality of fluidization near the reactor wall will deteriorate due to the wall effect , and this will ultimately affect the results of the reaction. Therefore, the pressure drop design parameters of the existing gas distribution plate are not suitable for the design requirements of a large-scale fluidized bed reactor.

In addition, the inventors of the present invention have discovered that in fluidized bed reactors, which are widely used at present, feed gas and air are supplied separately and their uniform mixing is ensured by the feed distributor and the gas distribution plate, and thus, if the wall effect is eliminated by blowing air in the opposite direction to the gas distribution plate, using the distribution pipe described in GB 1265770 A, the dispersion effect of the gas distribution plate will inevitably be adversely affected, and in turn this will influence the mixing of air and source gas. In addition, the separate arrangement of the distribution pipe not only increases the cost of the equipment, but also complicates the internal structure of the reactor, which may adversely affect the quality of fluidization.

In addition, the present inventors have discovered that a fluidized bed in which a bubble phase and a granular phase are present can be used in the production of acrylonitrile. In aggregation fluidization, gas moves upward through the bed mainly in the form of bubbles, and the movement of bubbles in the bed plays an important role in heat transfer, mass transfer and chemical reaction. After the gas passes through the distributor, bubbles may form. Bubbles are formed when gas enters the bed through the holes of the gas distribution plate, and the size and shape of the bubbles determine the characteristics of the catalyst particles, the characteristics of the gas, the diameter of the holes and the flow rate of gas passing through the holes, while the content of catalyst in the bubble phase is relatively low and may be approximately 1% of the total amount of catalyst in the bed, and exchange of material may occur between the gas and the entrained catalyst in the bubble phase, and between the catalyst and the entrained gas in the particulate phase, such that the gas in the particulate phase can enter the bubbles, and at the same time, part of the gas in the bubbles can also penetrate through the boundaries of the bubbles and enter the catalyst particles. Small bubbles turn out to be more favorable for mass transfer than large bubbles.

In addition, the present inventors have discovered that initial bubble formation, which is related to the gas flow rate through the orifices, at a position slightly above the gas distribution platen is critical to good fluidization quality in an acrylonitrile fluidized bed reactor. A typical fluidized bed gas distribution plate for acrylonitrile production is a perforated metal plate and requires equal and uniform gas velocity through each opening in order to achieve the same fluidization quality per unit cross-sectional area at a position slightly above the gas distribution plate.

In addition, the present inventors have discovered that since the fluid velocity exhibits a certain gradient between the position near the reactor wall and the center of the reactor due to the influence of objective factors such as viscosity and wall friction during the fluid movement, the fluid near the reactor wall is in a relatively static state, and the catalyst near the reactor wall is in a state of deposition downward relative to the catalyst in the center of the reactor. In other words, the catalyst in the center of the reactor has a higher fluidization quality than the catalyst near the reactor wall. The quality of fluidization near the reactor wall may deteriorate due to the wall effect, and therefore, the propylene ammoxidation reaction may not reach the optimal state, and, in turn, the degree of propylene conversion in the region near the reactor wall may decrease, resulting in an impact on the reaction result in throughout the reactor. This result cannot satisfy the requirement of increasing the reactor size. Thus, there is a need in the art to develop a gas distribution plate such that it is not possible to reduce the pressure drop of the gas distribution plate, but at the same time it is possible to reduce the impact of the wall effect on the quality of fluidization near the reactor wall, suppress the deterioration of the quality of fluidization of the catalyst near the reactor wall, and also satisfy the requirement of rapid and uniform mixing of gases from the distribution plate/distributor in a position close to the reactor wall.

As a result of numerous studies and experiments, the inventors of the present invention have found that the quality of fluidization near the reactor wall can be improved by correspondingly reducing the internal diameter of the nozzle near the reactor wall in order to increase the speed of the air fluid passing through the hole, so that the degree of conversion of the starting material in an appropriate position, and, in turn, the acrylonitrile yield of the entire reactor installation can be increased accordingly.

The present invention has been completed based on the discovery of the above facts.

In particular, the present invention relates to the following aspects:

1. A gas distribution plate, which is a metal plate containing holes located in the central region of the metal plate, called central holes, and holes located in the peripheral region of the metal plate, called peripheral holes, and the ratio D1/D1' of the hole diameter D1 for the central hole to the hole diameter D1' for the peripheral hole satisfies the expression 1.10 > D1/D1' > 1.01, the straight line distance between any point on the outer periphery of the metal plate and the center point of the metal plate being denoted by R, the area surrounded

- 2 045132 by all points on the metal plate at a distance r in a straight line from the central point is called the central region, and the region between the central region and the outer periphery is called the peripheral region, the value of r/R is from 0.7 to 0.85.

2. A gas distribution plate according to the first aspect, wherein the gas distribution plate is an air distribution plate for a fluidized bed ammoxidation reactor, and/or said metal plate is a flat metal plate, and/or 1.06 > D1/D1' > 1.01.

3. A gas distribution plate according to the first aspect, wherein the hole diameters D1 for all the central holes are the same or different from each other and are independently 16-60 mm, and/or the hole diameters D1' for all the peripheral holes are the same or different from each other and independently amount to 15-58 mm.

4. A gas distribution plate according to the third aspect, wherein the hole diameters D1 for all the central holes are the same or different from each other and are independently 22-52 mm, and/or the hole diameters D1' for all the peripheral holes are the same or different from each other and independently amount to 21-50 mm.

5. The gas distribution plate according to the first aspect, wherein the number of central holes is from 16 to 100 per square meter of the central area, and/or the number of peripheral holes is from 2 to 50 per square meter of the peripheral area, and/or the number of central holes is from 70 up to 99% in relation to the total number of holes in the metal plate.

6. The gas distribution plate according to the fifth aspect, in which the number of central holes is from 18 to 44 per square meter of the central area, and/or the number of peripheral holes is from 4 to 25 per square meter of the peripheral area, and/or the number of central holes is from 80 up to 95% relative to the total number of holes in the metal plate.

7. The gas distribution plate according to the first aspect, in which the number of central holes per unit area of the central region is substantially the same.

8. The gas distribution plate according to the first aspect, wherein the central holes and/or peripheral holes are arranged in substantially the shape of a square, an equilateral triangle, an equilateral diamond, or concentric circles.

9. The gas distribution plate according to the eighth aspect, in which the central holes and/or peripheral holes are arranged in a substantially square or equilateral triangle shape.

10. The gas distribution plate according to the first aspect, wherein the distances between any two adjacent central holes are the same or different from each other, and in each case are independently 100-300 mm, and/or the distances between any two adjacent peripheral holes are the same or different from each other, and in each case independently amount to 100-300 mm.

11. The gas distribution plate according to the tenth aspect, wherein the distances between any two adjacent central holes are the same or different from each other, and in each case independently are 150-270 mm, and/or the distances between any two adjacent peripheral holes are the same or different from each other, and in each case independently amount to 150-270 mm.

12. The gas distribution plate according to the first aspect, in which the metal plate has a substantially circular shape, the circle having a diameter of 5 to 29 m and a thickness of 5 to 40 mm.

13. The gas distribution plate according to the twelfth aspect, in which the circle has a diameter of 7 to 20 m and/or the metal plate has a thickness of 10 to 35 mm.

14. A gas distribution plate according to a first aspect, wherein at least one of the central holes has a nozzle called a central nozzle, wherein the central nozzle is a hollow pipe, and wherein the head end of the central nozzle is inserted into the central hole and is perpendicularly attached to the metal plate and is located coaxially with the central hole, and the tail end of the central nozzle has an opening called the central nozzle hole, and/or at least one of the peripheral holes has a nozzle called the peripheral nozzle, wherein the peripheral nozzle is a hollow pipe, and wherein the head the end of the peripheral nozzle is inserted into the peripheral hole, attached perpendicularly to the metal plate and positioned coaxially with the peripheral hole, and the tail end of the peripheral nozzle has an opening called the peripheral nozzle hole.

15. The gas distribution plate according to the fourteenth aspect, in which all the central holes have the specified nozzle, and/or all the peripheral holes have the specified nozzle.

16. The gas distribution plate according to the fourteenth aspect, in which the diameters d' of the holes for all the holes of the central nozzles are the same or different from each other and are independently from 5 to 20 mm, and/or the diameters d' of the holes for all the holes of the peripheral

- 3 045132 nozzles are the same or different from each other and independently range from 5 to 20 mm, and/or the hole diameter d for the central nozzle hole is identical or different from the hole diameter d' for the peripheral nozzle hole, and/or d/d ' satisfies the expression 1.10 >

d/d' > 1.00.

17. The gas distribution plate according to the sixteenth aspect, wherein the hole diameters d for all holes of the central nozzles are the same or different from each other and independently range from 10 to 16 mm, and/or the hole diameters d' for all holes of the peripheral nozzles are the same or different from each other and independently range from 10 to 16 mm, and/or d/d' satisfies the expression 1.04 > d/d' > 1.00.

18. The gas distribution plate according to the sixteenth aspect, in which the central nozzles and/or the peripheral nozzles have an injection angle α ranging from 2 to 20°.

19. The gas distribution plate according to the sixteenth aspect, in which the length of the central nozzle and/or the peripheral nozzle is 80-300 mm.

20. The gas distribution plate according to the sixteenth aspect, in which the opening diameter of the central nozzle opening is designated as d, the opening diameter of the peripheral nozzle opening is designated as d', the opening diameter of the central opening is designated D1, and the opening diameter of the peripheral opening is designated D1 ', (d'/D1')/(d/D1)=1-1.25.

21. Gas distribution plate according to the twentieth aspect, in which (d7D1')/(d/D1)=1.01-1.10.

22. The gas distribution plate according to the fourteenth aspect, in which the inner diameters D2 of all the central nozzles are the same or different from each other and independently range from 6 to 50 mm, and/or the inner diameters D2' of all the peripheral nozzles are the same or different from each other and independently range from 5 to 48 mm.

23. The gas distribution plate according to the twenty-second aspect, wherein the inner diameters D2 of all the central nozzles are the same or different from each other and independently range from 12 to 44 mm, and/or the inner diameters D2' of all the peripheral nozzles are the same or different from each other and independently range from 11 to 42 mm.

24. A gas distribution plate, which is a metal plate containing central holes located in the central region of the metal plate, and peripheral holes located in the peripheral region of the metal plate, and at least one of the central holes has a nozzle, called a central nozzle, and the central the nozzle is a hollow pipe, and the head end of the central nozzle is inserted into the central hole, attached perpendicularly to the metal plate and located coaxially with the central hole, and the tail end of the central nozzle has an opening called the central nozzle hole, and at least one of peripheral holes, there is a nozzle called a peripheral nozzle, wherein the peripheral nozzle is a hollow pipe, and wherein the head end of the peripheral nozzle is inserted into the peripheral hole, perpendicularly attached to the metal plate and positioned coaxially with the peripheral hole, and the tail end of the peripheral nozzle has a hole called the opening of the peripheral nozzle, and wherein the opening diameter of the central nozzle opening is designated as d, the opening diameter of the peripheral nozzle opening is designated as d', the opening diameter of the central opening is designated as D1, and the opening diameter of the peripheral opening is designated as D1', (d '/D1')/(d/D1)=1-1.25, and 1.10 > D1/D1' > 1.01, where the straight line distance between any point on the outer periphery of the metal plate and the center point of the metal plate denoted as R, the region surrounded by all the points on the metal plate at a distance r in a straight line from the center point is called the central region, and the region between the central region and the outer periphery is called the peripheral region, the value of r/R is from 0.7 to 0, 85.

25. The gas distribution plate according to the twenty-fourth aspect, wherein all the central holes have the specified nozzle, and/or all the peripheral holes have the specified nozzle, and/or (d'/D1')/(d/D1)=1.01-1, 10 and/or 1.06 > D1/D1' > 1.01.

26. A fluidized bed reactor comprising at least a housing, a fluidizing device chamber defined by the housing, and a gas distribution plate located in the fluidizing device chamber, wherein the gas distribution plate is a gas distribution plate according to claim 1 or 24.

27. The fluidized bed reactor according to the twenty-sixth aspect, wherein the fluidizing device chamber has a bed containing solid particles, and the pressure drop APd expressed in units of mPa of the gas distribution plate is 62-120% of the pressure drop APd expressed in units mPa, layer of solid particles.

28. The fluidized bed reactor according to the twenty-seventh aspect, wherein the solid particles are catalyst particles, and/or the pressure drop APd of the gas distribution plate is 68-110% of the pressure drop AP _b of the solid particle bed.

29. A method of ammoxidation, including a stage at which the C ₂ _ ₈ olefin is introduced into the reaction of am-

- 4 045132 ammoxidation using a gaseous oxidizer and obtaining an ammoxidation product, using a gas distribution plate according to the first or twenty-fourth aspect as a distribution plate for the gaseous oxidizer or in a fluidized bed reactor according to the twenty-sixth aspect.

Brief description of the figures

In fig. 1 is a schematic illustration of a fluidized bed reactor according to the present invention.

In fig. 2A and 2B are schematic diagrams of the arrangement of holes of a gas distribution plate according to the present invention.

In fig. 3 and 4 are schematic diagrams of a nozzle according to the present invention.

In fig. 5 is a schematic diagram of pressure measurement of a gas distribution plate according to the present invention.

List of symbols:

- fluidized bed reactor;

- hole of the gas distribution plate;

- gas distribution plate nozzle;

- wall of the fluidized bed reactor;

- an opening for measuring pressure above the distribution plate of the fluidized bed reactor;

- gas distribution plate;

- heat-removing water supply;

- air inlet of the fluidized bed reactor;

- hole for measuring pressure in the cone of the fluidized bed reactor;

- distributor of the initial mixture of propylene and ammonia.

Technical effects

By using the gas distribution plate according to the present invention, the effect of uniform distribution of gas can be realized.

By using the fluidizing device according to the present invention, good fluidization quality can be achieved.

By using the gas distribution plate according to the present invention, maximum catalyst utilization ratio can be obtained, and reduction of catalyst idle zones can be achieved.

By measuring the pressure difference APd of the gas distribution plate according to the present invention, the operating state of the gas distribution plate can be observed in real time.

Detailed Disclosure of the Present Invention

The present invention will be illustrated in detail hereinafter with reference to corresponding embodiments, but it should be noted that the scope of the present invention is not limited to these embodiments, but is defined by the appended claims.

All publications, patent applications, patents and other documents cited herein are incorporated herein by reference in their entirety. Unless otherwise defined, all technical and scientific terms used herein have the meanings commonly understood by those skilled in the art. In the event of a conflict, the contents of the description herein, including definitions, govern.

When materials, methods, components, devices or systems that are described herein are defined by terms known to those skilled in the art, generally known in the art or similar terms, it should be understood that the aforementioned materials, methods, components, devices or systems are not only those which are traditionally in use in the art at the time of filing this application, but also those which are not generally in use at the present time but will become generally known in the art as being suitable for a similar purpose.

In the context of describing the present invention, the term flat slab covers the case of a flat slab as well as the case of a substantially flat slab, which case is generally understood by those skilled in the art to be the case of a flat slab.

In the context of the present invention, the term practically means that tolerance is a deviation that is acceptable or considered reasonable by those skilled in the art, such as a deviation within ±10%, within ±5%, within ±1%, within ±0 .5% or within ±0.1%.

In the context of the present invention, unless specifically stated otherwise, all percentages, parts, ratios and other quantities are expressed by weight, and all quantities presented

- 5 045132 pressures are gauge pressures.

In the context of the present invention, any two or more embodiments of the present invention can be optionally combined, and the resulting technical solution forms part of the original disclosure of the present invention and is within the scope of the present invention.

According to an embodiment of the present invention, it relates to a gas distribution plate. Here, as the gas distribution plate, mention may be made in particular of an air distribution plate, in particular an air distribution plate used in an ammonia oxidation fluidized bed reactor or an acrylonitrile producing fluidized bed reactor. As is known, the gas distribution plate is generally present in the form of a perforated flat plate.

According to an embodiment of the present invention, the gas distribution plate is a metal plate, where holes (so-called central holes) are present in a central region of the metal plate, and holes (so-called peripheral holes) are present in a peripheral region of the metal plate. These holes are through holes passing through the metal plate from its upper surface to its lower surface, which are designed to introduce gas into the fluidizing device into the layer containing solid particles. Specifically, the straight line distance between any point on the outer periphery of a metal plate and the central point of the metal plate is denoted as R, the region which is surrounded by all points on the metal plate that are at a straight line distance r from the central point is called the central region, and the area between the central region and the outer periphery is called the peripheral region. Here, if the metal plate has a substantially circular shape, R represents the radius of the metal plate, and r represents the radius of the central region.

As is known, in particular for the use of an ammoxidation reactor or an acrylonitrile producing fluidized bed reactor, the metal plate is a flat metal plate. When a flat metal plate is used as a metal plate, it is possible to achieve a fluid velocity near the reactor wall that is no less than the fluid velocity at the center of the reactor, that is, a gas flow velocity passing through a peripheral opening can be achieved (see below). ), which is no less than the gas flow rate passing through the central hole (see below), and as a result the quality of catalyst fluidization near the reactor wall can be improved. Herein, the speed is generally a linear speed, which may range from about 6 m/s to about 25 m/s, although the present invention is not limited to this condition. In addition, the flow velocity can be easily determined by directly measuring the gas velocity at the outlet of the corresponding orifice.

According to an embodiment of the present invention, uniform distribution of gas or air can be achieved by passing gas through the gas distribution plate from one side to the other side. In this case, as described above, the gas flow rate passing through the peripheral hole is not less than the gas flow rate passing through the central hole.

According to an embodiment of the present invention, the r/R value is 0.2 to 0.99, preferably 0.5 to 0.9, and more preferably 0.7 to 0.85.

According to an embodiment of the present invention, the ratio D1/D1' of the hole diameter D1 (expressed in units of mm) for the central hole and the hole diameter D1' (expressed in units of mm) for the peripheral hole satisfies the expression 1.10 > D1/D1' > 1.00 , preferably 1.08 > D1/D1' > 1.00 and preferably 1.06 > D1/D1' > 1.01.

According to an embodiment of the present invention, the hole diameters D1 for all the central holes are the same or different from each other, preferably the same with respect to each other, and they are independently from 16 to 60 mm, preferably from 20 to 56 mm, and more preferably from 22 to 52 mm.

According to an embodiment of the present invention, the hole diameters D1' for all peripheral holes are the same or different from each other, preferably they are the same in relation to each other and are independently 15 to 58 mm, preferably 19 to 54 mm and more preferably 21 to 50 mm.

According to an embodiment of the present invention, the inventors of the present application have discovered through theoretical calculation and experimental confirmation regarding the initial bubbles that the number of central holes is from 16 to 100 per square meter of the area of the central region, preferably 17 to 64 or 18 to 44 per square meter area of the central region. To achieve a more uniform introduction of gas, it is advantageous that the central region contains the same number of central holes per unit cross-sectional area.

According to an embodiment of the present invention, the number of central holes is 70-99%, preferably 75-98%, and more preferably 80-95% with respect to the total number of holes in the metal plate.

According to an embodiment of the present invention, the inventors of the present application have discovered through theoretical calculation and experimental confirmation regarding the initial bubbles that the number of peripheral holes is from 2 to 50 per square meter of peripheral area, preferably from 3 to 44 or from 4 to 25 per square meter of peripheral area. To achieve a more uniform introduction of gas, it is advantageous that the peripheral region contains the same number of peripheral openings per unit cross-sectional area.

According to an embodiment of the present invention, the number of central holes per unit area of the central region is substantially the same.

According to an embodiment of the present invention, the arrangement of the central holes is not particularly limited, but practically they are arranged in a shape such as a square, an equilateral triangle, an equilateral quadrilateral (diamond), or concentric circles, preferably in a substantially square or equilateral triangle shape, as illustrated in FIG. . 2A and 2B.

According to an embodiment of the present invention, the arrangement of the peripheral holes is not particularly limited, but practically they are arranged in a shape such as a square, an equilateral triangle, an equilateral quadrilateral (diamond) or concentric circles, preferably in a substantially square or equilateral triangle shape, as illustrated in FIG. 2A and 2B.

Taking as an example an acrylonitrile producing reactor with a fluidized bed and a square shaped hole arrangement, as illustrated in FIG. 2A, the inventors of the present application have discovered that if the distance between the holes is significantly greater than the diameter of the bubbles, then the gas exiting the four holes is sufficient to fluidize the catalyst in the center of the square in the upward movement, and the non-fluidized catalyst representing forming a thin, stationary layer, will cause an ammoxidation reaction of the feed gas on the surface of the catalyst and ultimately lose activity due to excessive reduction. The catalyst at the center of the square does not participate in the propylene ammoxidation reaction, and as a result, the catalyst utilization rate decreases, the catalyst loading in the reactor increases, and ultimately the reaction result is adversely affected. On the other hand, the distance between the holes should not be too small. When the distance between the holes is less than the diameter of the bubbles, coalescence of the bubbles that are formed above the adjacent holes can easily occur, and since the volume of the bubble formed as a result of coalescence is more than the sum of the volumes of the two bubbles before coalescence, the reaction gas can pass through the layer in greater quantities by destruction of bubbles, as a result of this, the likelihood of contact between the gas and catalyst particles is reduced, the efficiency of mass transfer is reduced, and, ultimately, the performance characteristics of the reaction deteriorate. Thus, a suitable spacing between holes is desirable to ensure a good initial fluidized state in the fluidized bed, and it is preferred that the spacing between holes is somewhat less than the diameter of the bubbles that initially form on the gas distribution plate.

According to an embodiment of the present invention, the inventors of the present application have discovered through theoretical calculation and experimental confirmation regarding the initial bubbles that the distances between any two adjacent central holes (i.e., the distance between the holes) are the same or different from each other, preferably are identical in relation to each other, and in each case independently amount to 100-300 mm, preferably 125-285 mm and more preferably 150-270 mm. Here, the distance between the holes is defined as the length of the side of the figure in which the holes are located.

According to an embodiment of the present invention, the inventors of the present application have discovered through theoretical calculation and experimental confirmation regarding the initial bubbles that the distances between any two adjacent peripheral holes (i.e., the distance between the holes) are the same or different from each other, preferably are identical in relation to each other, and in each case independently amount to 100-300 mm, preferably 125-285 mm and more preferably 150-270 mm. Here, the distance between the holes is defined as the length of the side of the figure in which the holes are located.

According to an embodiment of the present invention, the metal plate has a substantially circular shape, the diameter of the circle being typically 5-29 m and preferably 7-20 m.

- 7 045132

According to an embodiment of the present invention, the thickness of the metal plate is generally from 5 to 40 mm and preferably from 10 to 35 mm.

According to an embodiment of the present invention, at least one and preferably all of the central holes have a nozzle (a so-called central nozzle). In addition, at least one and preferably all of the peripheral openings have a nozzle (so-called peripheral nozzle).

According to an embodiment of the present invention, the central nozzle is a hollow pipe, and the head end of the central nozzle is inserted into a central hole perpendicularly connected to the metal plate and located coaxially with the central hole. Preferably, a hole (called a center hole) is present at the end of the central nozzle. Moreover, the peripheral nozzle is a hollow tube, and the head end of the peripheral nozzle is inserted into a peripheral hole perpendicularly connected to the metal plate and positioned coaxially with the peripheral hole. Preferably, at the end of the peripheral nozzle there is an opening (the so-called peripheral opening).

The inventors of the present invention have found that in order to prevent erosion of solid particles such as catalyst particles by the action of gas having a high velocity, when introducing a fluidizing device such as a fluidized bed reactor into the interior space through the gas inlet 8, generally the gas does not have to pass directly through the holes in the gas distribution plate, but instead it must pass through the nozzles 3 that are present on the metal plate constituting the gas distribution plate 6, as illustrated in FIG. 3. Multiple nozzles 3 are located on the lower surface of the metal plate and correspond one-to-one with holes in the metal plate. The upper end of the nozzle 3 is connected to the hole in the metal plate, the middle part as the main body of the nozzle is a cylindrical hollow metal pipe, and the lower end of the nozzle contains a hole 2. The nozzle is located perpendicular to the metal plate, with the nozzle body, the hole of the plate and The nozzle openings are coaxial. Thus, a short pipe (ie a nozzle) is used to connect the plate opening and the nozzle opening, the plate opening, the nozzle opening and the nozzle being coaxial. Moreover, in order to achieve the flow straightening effect, the inner diameter D of the nozzle 3 is larger than the diameter d of the hole 2, and at the other end, the diameter of the plate hole is the same as the outer diameter of the nozzle 3. Regarding the inner diameter D of the nozzle 3, generally , it is set so as to provide a gas velocity in the nozzle body in the range of 8 to 50 m/s and preferably from 12 to 40 m/s.

According to an embodiment of the present invention, the connection between the nozzle and the metal plate is not particularly limited, and a conventional connection such as a weld or a screw connection can be used.

According to an embodiment of the present invention, the hole diameters d for all holes of the central nozzles are the same or different from each other, preferably the same in relation to each other, and independently range from 5 to 20 mm, preferably from 7 to 18 mm and more preferably from 10 to 16 mm.

According to an embodiment of the present invention, the hole diameters d' of all the holes of the peripheral nozzles are the same or different from each other, preferably the same in relation to each other, and independently range from 5 to 20 mm, preferably from 7 to 18 mm and more preferably from 10 up to 16 mm.

According to an embodiment of the present invention, the hole diameter d of the central nozzle hole is the same as or different from the hole diameter d' of the peripheral nozzle hole. Preferably, d/d' satisfies the expression 1.10 > d/d' > 1.00 and preferably 1.04 > D/d' > 1.00.

The inventors of the present application have discovered through a hydro-aero-mechanical study that since the speed and direction of movement of the fluid changes with the change in diameter as the gas moves through the hole into the nozzle, reverse flow of a portion of the fluid can be created near the position with the change in diameter, which can cause a change in the state of the fluid in the above-mentioned position, such as a change from laminar motion to turbulent motion, and the fluid in the turbulent region is in a state of disordered and unstable motion. The turbulent region gradually approaches the pipe wall along the flow direction of the fluid until the turbulent region disappears, such that the fluid flow state gradually turns into a stable laminar movement along the flow direction. When viewed from the fluid flow region, in the region from the position where the diameter changes to the position where the turbulent region disappears, a certain boundary line exists between the turbulent flow layer and the laminar flow layer. As illustrated in FIG. 4, the length of the nozzle 3 from the position with a change in diameter to the upper surface of the gas distribution plate is designated as the length L nozzle, and the length of the nozzle 3 from the position with a change in diameter to the position at which the turbulent region disappears is designated as the minimum length of the nozzle 1,

The injection angle α can be expressed by the following equation (1):

a = 2acrtg(D/2L) (1)

The injection angle β can be expressed by the following equation (2):

β = 2acrtg(D/21) (2)

Here, D represents the inner diameter of the nozzle, which is expressed in units of mm, L represents the length of the nozzle, which is expressed in units of mm, and 1 represents the minimum length of the nozzle, which is expressed in units of mm.

According to the present invention, as can be seen from the above equations (1) and/or (2), the smaller the injection angle α and/or β, i.e. the smaller the ratio of the internal diameter D of the nozzle and the length L and/or 1 nozzle, the greater the required length L and/or 1 nozzle for a fixed internal diameter D of the nozzle. However, only in the case where the nozzle length L is more than or equal to the minimum nozzle length 1 can a situation be achieved in which the irregular air flow movement created due to the change in diameter is converted into a stable linear air flow movement such that the gas may have a stable flow rate and a stable air flow direction as it passes through the orifice.

According to an embodiment of the present invention, the injection angle α of the central nozzle is 2° to 20°, preferably 4° to 17°, and more preferably 5° to 14°. In addition, the injection angle α of the peripheral nozzle is 2° to 20°, preferably 4° to 17°, and more preferably 5° to 14°.

According to an embodiment of the present invention, the length of the central nozzle is 80-300 mm, preferably 100-270 mm, and more preferably 120-240 mm.

According to an embodiment of the present invention, the length of the peripheral nozzle is 80-300 mm, preferably 100-270 mm, and more preferably 120-240 mm.

The inventors of the present application have discovered through numerous calculations and experiments that, under the most preferred conditions, an optimal flow straightening effect can be achieved when the injection angle α is from 5° to 14° and the nozzle length is from 120 to 240 mm.

According to an embodiment of the present invention, the hole diameter D1 for the central hole is the same as or different from the hole diameter D1' for the peripheral hole. Preferably, the hole diameter D1 is greater than the hole diameter D1'. In particular, when 1.10 > D1/D1' > 1.00, the quality of fluidization, which deteriorates due to the wall effect, can be effectively improved. More preferably, the ratio D1/D1' is set so as to satisfy the conditions 1.08 > D1/D1' > 1.00, even more preferably the ratio D1/D1' is set so as to satisfy the conditions 1.06 > D1/D1' > 1 ,01. When D1/D1' is more than 1.10, the flow straightening effect may be reduced.

According to an embodiment of the present invention, when the opening diameter of the central nozzle opening is designated as d (expressed in units of mm), the opening diameter of the peripheral nozzle opening is designated as d' (expressed in units of mm), the opening diameter of the central opening is designated as D1 (expressed in units of mm). in units of mm), and the hole diameter for the peripheral hole is designated as D1' (expressed in units of mm), (d'/D1')/(d/D1) α1, preferably (d'/D1')/(d/D1 )=1-1.25, (d'/D1')/(d/D1)=1-1.20 or (d'/D1')/(d/D1)=1.01-1.10.

According to an embodiment of the present invention, the inner diameters D2 of all the central nozzles are the same or different from each other, preferably the same with respect to each other, and are independently 6-50 mm, preferably 10-47 mm and more preferably 12-44 mm.

According to an embodiment of the present invention, the inner diameters D2' of all peripheral nozzles are the same or different from each other, preferably the same with respect to each other, and are independently 5-48 mm, preferably 9-45 mm and more preferably 11-42 mm.

According to an embodiment of the present invention, the inner diameter D2 of the central nozzle is the same or different from the inner diameter D2' of the peripheral nozzle. Preferably, the inner diameter D2 is greater than the inner diameter D2', and preferably D2/D2' satisfies the expression 1.10 > D2/D2' > 1.00, preferably 1.08 > D2/D2' > 1.00, and more preferably 1, 06 > D2/D2' > 1.01.

According to an embodiment of the present invention, it also relates to a fluidizing device, in particular such as a fluidized bed reactor, more particularly a fluidized bed ammonia oxidation reactor. The fluidizing device contains at least a housing, a fluidizing device chamber defined by the housing, and a gas distribution plate located in the fluidizing device chamber. Here, the gas distribution plate is a gas distribution plate according to any of the preceding aspects of the present invention.

According to an embodiment of the present invention, the connection method of the gas distribution plate in the fluidizing device is not particularly limited, and any connection method conventionally used in the art can be used.

According to an embodiment of the present invention, the inner chamber of the fluidizing device contains a layer of solid particles, in particular catalyst particles, more particularly ammonia oxidation catalyst particles. Here, the ammonia oxidation catalyst may be any ammonia oxidation catalyst which is conventionally known in the art, and is not particularly limited.

According to an embodiment of the present invention, it also relates to an oxidation or ammoxidation method, including the step of introducing a starting material into an oxidation or ammoxidation reaction with a gaseous oxidizing agent and obtaining an oxidation or ammoxidation product. Specific examples _of the feedstock are waste and hydrocarbon feedstocks, particularly _C2-8 olefins or propylene. Mention may be made in particular of air or oxygen as gaseous oxidizing agent. As the oxidation product or ammoxidation product, propylene oxide or acrylonitrile may be mentioned in particular. Moreover, the reaction method is carried out using a gas distribution plate according to any of the preceding aspects of the present invention as a gas distribution plate for an oxidant gas or in a fluidized bed reactor according to any of the preceding aspects of the present invention.

It has been discovered by the present inventors that the pressure drop APd of the gas distribution plate is an important parameter when the fluidizing device is in operation, in particular when the reactor is used for the oxidation of propylene and ammonia in an acrylonitrile producing fluidized bed reactor. Properly setting the differential pressure of the gas distribution plate can ensure that each nozzle of the gas distribution plate receives gas flow at the same rate, and the rate of gas flow per unit cross-sectional area of the device is the same. During the processing of gas passing through the orifice, a local pressure loss will be generated, which is the pressure difference between the position indicated by number 5 and the position indicated by number 9 in FIG. 5, the above-mentioned pressure difference being the pressure difference APd of the gas distribution plate. The greater the pressure drop APd of the distribution plate in the fluidizing device, the more uniform the gas distribution.

In addition, the present inventors have discovered that there is a correlation between the pressure drop APd of the gas distribution plate, the distance between the holes, the speed of the gas passing through the hole, and the diameter of the nozzle hole. For fluidizing devices such as acrylonitrile producing fluidized bed reactors of the same size, if the distances between the holes are the same, the higher the pressure drop APd of the gas distribution plate, the higher the gas velocity passing through the hole and the smaller the required nozzle hole diameter. However, the nozzle opening diameter cannot be set too low. Otherwise, on the one hand, abrasive wear of the nozzle hole may increase due to the high speed of the gas passing through the hole, and, on the other hand, the nozzle hole may be easily blocked by foreign particles. Likewise, if the nozzle orifice diameters are the same, for a device having a larger gas distribution plate pressure drop APd, the gas velocity passing through the orifice is higher and a larger distance between orifices is required. In this case, too, the distance between the holes cannot be infinitely large or infinitely small, but must be in correlation with the size of the bubbles that are formed at a position slightly above the distribution plate.

In addition, the present inventors have discovered that the pressure drop APd of an existing gas distribution plate is generally set at 60% of the bed pressure drop. However, as the scale of production continually increases, the diameter of the fluidizing device, such as an acrylonitrile producing fluidized bed reactor, also increases. For example, for an acrylonitrile-producing fluidized bed reactor that has a diameter greater than 8.5 m, if a design parameter of 60% bed pressure drop is adopted, a larger diameter nozzle orifice or smaller hole spacing will be required compared to the case where the design parameter accounts for more than 60% of the layer pressure drop. A large diameter nozzle opening is more likely to cause the catalyst to fall into the reactor cone and not be used, which is undesirable; alternatively, if the distance between the holes is small, the number of holes will be large and the number of air nozzles will increase, and the number of branch pipes and propylene and ammonia distributor nozzles to which the air nozzles correspond one-to-one will also increase, resulting in there will be an increase in equipment costs. According to the present invention, taking into account factors such as the diameter of the nozzle hole, the distance between the holes and the speed of the gas passing through the hole, it is advisable to set the differential pressure AP _d of the gas distribution plate at 62-120% of the differential pressure AP _b of the layer, preferably 65- 115% of the AP _b layer pressure drop and preferably 68-110% of the AP _b layer pressure drop so that the objective of ensuring the same gas flow rate per unit cross-sectional area of the device can be better achieved.

According to a preferred embodiment of the present invention, the gas passing through the gas distribution platen is subjected to the same conditions of temperature, pressure, etc., in a fluidizing device such as an acrylonitrile producing fluidized bed reactor. In order to control the pressure drop APd of the gas distribution plate within the preferred range, the above parameters corresponding to APd are generally selected as follows: AP _d is set at 62-120% of the layer pressure drop AP _b , with the nozzle orifice diameter at the lower end The nozzle of the gas distribution plate is 5-20mm, and the distance between the holes of the gas distribution plate is 100-300mm. Preferably, AP _d is set at a level of 65-115% of the pressure drop AP _b of the layer, with the nozzle opening diameter being 7-18 mm and the distance between the openings being 125-285 mm. Preferably, AP _d is set at a level of 68-110% of the pressure drop AP _b of the layer, with the nozzle opening diameter being 10-16 mm and the distance between the openings being 150-270 mm. At the same time, when AP _d is within the above range, abrasive wear of the nozzle hole, which is caused by high gas velocity passing through the holes, can be prevented.

According to an embodiment of the present invention, the ammoxidation method can be carried out in any modes and in any ways that are conventionally known in the art, and since the relevant information is known to one skilled in the art, a detailed description thereof is not provided herein. However, in specific examples, the reaction method is carried out under the following conditions: the molar ratio of propylene, ammonia and air (in terms of molecular oxygen) is usually 1:1.1-1.3:1.8-2, 0, the reaction temperature is generally 420-440°C, the reaction pressure (gauge pressure) is generally 0.03-0.14MPa, and the hourly feed rate of the raw materials is generally 0.04- 0.10 h ^-1 .

Examples

The present invention will now be described in further detail and with reference to examples and comparative examples, but the present invention is not limited to the following examples.

In the following examples and comparative examples, the acrylonitrile yield and propylene conversion after one pass can be calculated using the following equations:

Acrylonitrile yield after one pass: AN% = C _AN /ΣCχ100

Propylene conversion degree: C _C3 % = (1-C _C3in /C _C3out )x100 and:

_CAN : molar amount (mol) of carbon contained in acrylonitrile in the reactor outlet gas

ΣC: total molar amount (mol) of carbon contained in the reactor outlet gas

C _c3out : molar amount (mol) of carbon contained in propylene in the reactor outlet gas

C _C3in : molar amount (mol) of carbon contained in propylene in the reactor inlet gas

In the following examples and comparative examples, the fluidized state of the fluidized bed can also be characterized by a pressure pulsation intensity graph or related data.

Comparative example 1.

As illustrated in FIG. 5, in the fluidized bed reactor, the diameter was 9.0 m, the propylene injection rate was 9500 Nm ³ /h, the reaction temperature was 430°C, the reaction pressure was 0.04 MPa, and the ratio of propylene, ammonia and air was 1:1 ,2:9.6.

The air distribution plate 6 was a circular metal plate whose diameter was 9.0 m, the thickness was 16 mm, and the radius r of the central region was 7.92 m.

The number of central holes was 29 per square meter of the central area, each of the central holes had a hole diameter D1 of 42 mm, and they were evenly spaced in a square shape with the distance between the holes being 197 mm, each of the central nozzle holes had a hole diameter d of 14.3 mm, and the inner diameter of D2 was 36 mm.

The number of peripheral holes was 20.5 per square meter of the peripheral area, the hole diameters D1' for the peripheral holes were 36 mm, respectively, the distance

- 11 045132 between adjacent peripheral holes was 197 mm, the hole diameters d' for the peripheral nozzle holes were 14.3 mm, respectively, and the inner diameter D2' was 30 mm.

The D1/D1' ratio was 1.17, the d/d' ratio was 1, and the (d'/D1')/(d/D1) ratio was 1.17.

The compositions of the gas phase in the central region, in the near-wall region and at the outlet of the reactor were measured separately, and the corresponding results are presented in the table.

Comparative example 2.

As illustrated in FIG. 5, in the fluidized bed reactor, the diameter was 9.0 m, the propylene injection rate was 9500 Nm ³ /h, the reaction temperature was 430°C, the reaction pressure was 0.04 MPa, and the ratio of propylene, ammonia and air was 1:1 ,2:9.6.

The air distribution plate 6 was a circular metal plate whose diameter was 9.0 m, the thickness was 16 mm, and the radius r of the central region was 7.92 m.

The number of central holes was 29 per square meter of the central area, each of the central holes had a hole diameter D1 of 42 mm, and they were evenly spaced in a square shape with the distance between the holes being 197 mm, each of the central nozzle holes had a hole diameter d of 14.3 mm, and the inner diameter of D2 was 36 mm.

The number of peripheral holes was 20.5 per square meter of the peripheral area, the hole diameters D1' for the peripheral holes were 42 mm, respectively, the distance between adjacent peripheral holes was 197 mm, the hole diameters d' for the peripheral nozzle holes were 14.3 mm, respectively , and the inner diameter D2' was 36 mm.

The D1/D1' ratio was 1.00, the d/d' ratio was 1, and the (d'/D1')/(d/D1) ratio was 1.00.

The compositions of the gas phase in the central region, in the near-wall region and at the outlet of the reactor were measured separately, and the corresponding results are presented in the table.

Example 1.

As illustrated in FIG. 5, in the fluidized bed reactor, the diameter was 9.0 m, the propylene injection rate was 9500 Nm ³ /h, the reaction temperature was 430°C, the reaction pressure was 0.04 MPa, and the ratio of propylene, ammonia and air was 1:1 ,2:9.6.

The air distribution plate 6 was a circular metal plate whose diameter was 9.0 m, the thickness was 16 mm, and the radius r of the central region was 7.92 m.

The number of central holes was 29 per square meter of the central area, each of the central holes had a hole diameter D1 of 42 mm, and they were evenly spaced in a square shape with the distance between the holes being 197 mm, each of the central nozzle holes had a hole diameter d of 14.3 mm, and the inner diameter of D2 was 36 mm. The speed of the gas passing through the central hole was 10.6 m/s.

The number of peripheral holes was 20.5 per square meter of the peripheral area, the hole diameters D1' for the peripheral holes were 40 mm, respectively, the distance between adjacent peripheral holes was 197 mm, the hole diameters d' for the peripheral nozzle holes were 14.3 mm, respectively , the inner diameter of D2' was 34 mm, and the speed of the gas passing through the peripheral hole was 11.8 m/s.

The D1/D1' ratio was 1.05, the d/d' ratio was 1, and the (d'/D1')/(d/D1) ratio was 1.05.

The compositions of the gas phase in the central region, in the near-wall region and at the outlet of the reactor were measured separately, and the corresponding results are presented in the table.

Example 2.

As illustrated in FIG. 5, in the fluidized bed reactor, the diameter was 9.0 m, the propylene injection rate was 9500 Nm ³ /h, the reaction temperature was 430°C, the reaction pressure was 0.04 MPa, and the ratio of propylene, ammonia and air was 1:1 ,2:9.6.

The air distribution plate 6 was a circular metal plate whose diameter was 9.0 m, the thickness was 16 mm, and the radius r of the central region was 7.92 m.

The number of central holes was 29 per square meter of the central area, each of the central holes had a hole diameter D1 of 42 mm, and they were evenly spaced in a square shape with the distance between the holes being 197 mm, each of the central nozzle holes had a hole diameter d of 14.3 mm, and the inner diameter of D2 was 36 mm.

The number of peripheral holes was 20.5 per square meter of the peripheral area, the hole diameters D1' for the peripheral holes were 39 mm, respectively, the distance between adjacent peripheral holes was 197 mm, the hole diameters d' for the peripheral nozzle holes were 14.3 mm, respectively , and the inner diameter D2' was 35 mm.

The D1/D1' ratio was 1.08, the d/d' ratio was 1, and the ratio

- 12 045132 (d'/D1')/(d/D1) was 1.08.

The compositions of the gas phase in the central region, in the near-wall region and at the outlet of the reactor were measured separately, and the corresponding results are presented in the table.

Example 3.

As illustrated in FIG. 5, in the fluidized bed reactor, the diameter was 9.0 m, the propylene injection rate was 9500 Nm ³ /h, the reaction temperature was 430°C, the reaction pressure was 0.04 MPa, and the ratio of propylene, ammonia and air was 1:1 ,2:9.6.

The air distribution plate 6 was a circular metal plate whose diameter was 9.0 m, the thickness was 16 mm, and the radius r of the central region was 7.92 m.

The number of central holes was 13 per square meter of the central area, each of the central holes had a hole diameter D1 of 51 mm, and they were evenly spaced in a square shape with a distance of 275 mm between the holes, each of the central nozzle holes had a hole diameter d was 15.1 mm, and the inner diameter of D2 was 45 mm.

The number of peripheral holes was 9 per square meter of the peripheral area, the hole diameters D1' for the peripheral holes were 48 mm, respectively, the distance between adjacent peripheral holes was 275 mm, the hole diameters d' for the peripheral nozzle holes were 15.1 mm, respectively, and the internal diameter D2' was 42 mm.

The D1/D1' ratio was 1.06, the d/d' ratio was 1, and the (d'/D1')/(d/D1) ratio was 1.06.

The compositions of the gas phase in the central region, in the near-wall region and at the outlet of the reactor were measured separately, and the corresponding results are presented in the table.

Example 4.

As illustrated in FIG. 5, in the fluidized bed reactor, the diameter was 9.0 m, the propylene injection rate was 9500 Nm ³ /h, the reaction temperature was 430°C, the reaction pressure was 0.04 MPa, and the ratio of propylene, ammonia and air was 1:1 ,2:9.6.

The air distribution plate 6 was a circular metal plate whose diameter was 9.0 m, the thickness was 16 mm, and the radius r of the central region was 7.92 m.

The number of central holes was 118 per square meter of the central area, each of the central holes had a hole diameter D1 of 25 mm, and they were evenly spaced in a triangle shape with a distance of 95 mm between the holes, each of the central nozzle holes had a hole diameter d was 9.6 mm, and the inner diameter of D2 was 20 mm.

The number of peripheral holes was 84 per square meter of the peripheral area, the hole diameters D1' for the peripheral holes were 24 mm, respectively, the distance between adjacent peripheral holes was 95 mm, the hole diameters d' for the peripheral nozzle holes were 9.6 mm, respectively, and the internal diameter D2' was 19 mm.

The D1/D1' ratio was 1.04, the d/d' ratio was 1, and the (d'/D1')/(d/D1) ratio was 1.04.

The compositions of the gas phase in the central region, in the near-wall region and at the outlet of the reactor were measured separately, and the corresponding results are presented in the table.

Example 5.

As illustrated in FIG. 5, in the fluidized bed reactor, the diameter was 9.0 m, the propylene injection rate was 9500 Nm ³ /h, the reaction temperature was 430°C, the reaction pressure was 0.04 MPa, and the ratio of propylene, ammonia and air was 1:1 ,2:9.6.

The air distribution plate 6 was a circular metal plate whose diameter was 9.0 m, the thickness was 16 mm, and the radius r of the central region was 7.92 m.

The number of central holes was 29 per square meter of the central area, each of the central holes had a hole diameter D1 of 42 mm, and they were evenly spaced in a square shape with the distance between the holes being 197 mm, each of the central nozzle holes had a hole diameter d of 14.3 mm, and the inner diameter of D2 was 36 mm.

The number of peripheral holes was 20.5 per square meter of the peripheral area, the hole diameters D1' for the peripheral holes were 40 mm, respectively, the distance between adjacent peripheral holes was 197 mm, the hole diameters d' for the peripheral nozzle holes were 14.1 mm, respectively , and the inner diameter D2' was 34 mm.

The D1/D1' ratio was 1.05, the d/d' ratio was 1.01, and the (d'/D1')/(d/D1) ratio was 1.04.

The compositions of the gas phase in the central region, in the near-wall region and at the outlet of the reactor were measured separately, and the corresponding results are presented in the table.

Example 6.

As illustrated in FIG. 5, in the fluidized bed reactor, the diameter was 9.0 m, the propylene injection rate was 9500 Nm ³ /h, the reaction temperature was 430°C, the pressure

- 13 045132 reaction was 0.04 MPa, and the ratio of propylene, ammonia and air was 1:1.2:9.6.

The air distribution plate 6 was a circular metal plate whose diameter was 9.0 m, the thickness was 16 mm, and the radius r of the central region was 7.92 m.

The number of central holes was 29 per square meter of the central area, each of the central holes had a hole diameter D1 of 42 mm, and they were evenly spaced in a square shape with the distance between the holes being 197 mm, each of the central nozzle holes had a hole diameter d of 14.3 mm, and the inner diameter of D2 was 36 mm.

The number of peripheral holes was 20.5 per square meter of the peripheral area, the hole diameters D1' for the peripheral holes were 39 mm, respectively, the distance between adjacent peripheral holes was 197 mm, the hole diameters d' for the peripheral nozzle holes were 12.7 mm, respectively , and the inner diameter D2' was 33 mm.

The D1/D1' ratio was 1.08, the d/d' ratio was 1.13, and the (d'/D1')/(d/D1) ratio was 0.96.

The compositions of the gas phase in the central region, in the near-wall region and at the outlet of the reactor were measured separately, and the corresponding results are presented in the table.

Example 7.

As illustrated in FIG. 5, in the fluidized bed reactor, the diameter was 9.0 m, the propylene injection rate was 9500 Nm ³ /h, the reaction temperature was 430°C, the reaction pressure was 0.04 MPa, and the ratio of propylene, ammonia and air was 1:1 ,2:9.6.

The air distribution plate 6 was a circular metal plate whose diameter was 9.0 m, the thickness was 16 mm, and the radius r of the central region was 7.92 m.

The number of central holes was 29 per square meter of the central area, each of the central holes had a hole diameter D1 of 42 mm, and they were evenly spaced in a square shape with the distance between the holes being 197 mm, each of the central nozzle holes had a hole diameter d of 14.3 mm, and the inner diameter of D2 was 36 mm.

The number of peripheral holes was 20.5 per square meter of the peripheral area, the hole diameters D1' for the peripheral holes were 40 mm, respectively, the distance between adjacent peripheral holes was 197 mm, the hole diameters d' for the peripheral nozzle holes were 15.2 mm, respectively , and the inner diameter D2' was 34 mm.

The D1/D1' ratio was 1.05, the d/d' ratio was 0.94, and the (d'/D1')/(d/D1) ratio was 1.12.

The compositions of the gas phase in the central region, in the near-wall region and at the outlet of the reactor were measured separately, and the corresponding results are presented in the table.

Example 8.

As illustrated in FIG. 5, in the fluidized bed reactor, the diameter was 9.0 m, the propylene injection rate was 9500 Nm ³ /h, the reaction temperature was 430°C, the reaction pressure was 0.04 MPa, and the ratio of propylene, ammonia and air was 1:1 ,2:9.6.

The air distribution plate 6 was a circular metal plate whose diameter was 9.0 m, the thickness was 16 mm, and the radius r of the central region was 7.92 m.

The number of central holes was 29 per square meter of the central area, each of the central holes had a hole diameter D1 of 42 mm, and they were evenly spaced in a square shape with the distance between the holes being 197 mm, each of the central nozzle holes had a hole diameter d of 14.3 mm, the inner diameter D2 was 36 mm, and the nozzle injection angle α was 12°.

The number of peripheral holes was 20.5 per square meter of the peripheral area, the hole diameters D1' for the peripheral holes were 40 mm, respectively, the distance between adjacent peripheral holes was 197 mm, the hole diameters d' for the peripheral nozzle holes were 14.3 mm, respectively , the inner diameter D2' was 34 mm, and the injection angle α of the nozzle was 12°.

The D1/D1' ratio was 1.05, the d/d' ratio was 1, and the (d'/D1')/(d/D1) ratio was 1.05.

The compositions of the gas phase in the central region, in the near-wall region and at the outlet of the reactor were measured separately, and the corresponding results are presented in the table.

Example 9.

As illustrated in FIG. 5, in the fluidized bed reactor, the diameter was 9.0 m, the propylene injection rate was 9500 Nm ³ /h, the reaction temperature was 430°C, the reaction pressure was 0.04 MPa, and the ratio of propylene, ammonia and air was 1:1 ,2:9.6.

The air distribution plate 6 was a circular metal plate whose diameter was 9.0 m, the thickness was 16 mm, and the radius r of the central region was 7.92 m.

- 14 045132

The number of central holes was 29 per square meter of the central area, each of the central holes had a hole diameter D1 of 42 mm, and they were evenly spaced in a square shape with the distance between the holes being 197 mm, each of the central nozzle holes had a hole diameter d of 14.3 mm, the inner diameter D2 was 36 mm, and the nozzle injection angle α was 3°.

The number of peripheral holes was 20.5 per square meter of the peripheral area, the hole diameters D1' for the peripheral holes were 40 mm, respectively, the distance between adjacent peripheral holes was 197 mm, the hole diameters d' for the peripheral nozzle holes were 14.3 mm, respectively , the inner diameter D2' was 34 mm, and the injection angle α of the nozzle was 3°.

The D1/D1' ratio was 1.05, the d/d' ratio was 1, and the (d'/D1')/(d/D1) ratio was 1.05.

The compositions of the gas phase in the central region, in the near-wall region and at the outlet of the reactor were measured separately, and the corresponding results are presented in the table.

Due to the small injection angle, the nozzle length is 687 mm, and the device can be implemented but is not economical.

Example 10.

As illustrated in FIG. 5, in the fluidized bed reactor, the diameter was 9.0 m, the propylene injection rate was 9500 Nm ³ /h, the reaction temperature was 430°C, the reaction pressure was 0.04 MPa, and the ratio of propylene, ammonia and air was 1:1 ,2:9.6.

The air distribution plate 6 was a circular metal plate whose diameter was 9.0 m, the thickness was 16 mm, and the radius r of the central region was 7.92 m.

The number of central holes was 29 per square meter of the central area, each of the central holes had a hole diameter D1 of 42 mm, and they were evenly spaced in a square shape with the distance between the holes being 197 mm, each of the central nozzle holes had a hole diameter d of 14.3 mm, the inner diameter D2 was 36 mm, and the nozzle injection angle α was 25°.

The number of peripheral holes was 20.5 per square meter of the peripheral area, the hole diameters D1' for the peripheral holes were 40 mm, respectively, the distance between adjacent peripheral holes was 197 mm, the hole diameters d' for the peripheral nozzle holes were 14.3 mm, respectively , the inner diameter D2' was 34 mm, and the injection angle α of the nozzle was 25°.

The D1/D1' ratio was 1.05, the d/d' ratio was 1, and the (d'/D1')/(d/D1) ratio was 1.05.

The compositions of the gas phase in the central region, in the near-wall region and at the outlet of the reactor were measured separately, and the corresponding results are presented in the table.

Example 11.

As illustrated in FIG. 5, in the fluidized bed reactor, the diameter was 9.0 m, the propylene injection rate was 9500 Nm ³ /h, the reaction temperature was 430°C, the reaction pressure was 0.04 MPa, and the ratio of propylene, ammonia and air was 1:1 ,2:9.6.

The air distribution plate 6 was a circular metal plate whose diameter was 9.0 m, the thickness was 16 mm, and the radius r of the central region was 7.92 m.

The number of central holes was 29 per square meter of the central area, each of the central holes had a hole diameter D1 of 42 mm, and they were evenly spaced in a square shape with the distance between the holes being 197 mm, each of the central nozzle holes had a hole diameter d of 14.3 mm, and the inner diameter of D2 was 36 mm.

The number of peripheral holes was 20.5 per square meter of the peripheral area, the hole diameters D1' for the peripheral holes were 41 mm, respectively, the distance between adjacent peripheral holes was 197 mm, the hole diameters d' for the peripheral nozzle holes were 12.7 mm, respectively , and the inner diameter D2' was 35 mm.

The D1/D1' ratio was 1.02, the d/d' ratio was 1.13, and the (d'/D1')/(d/D1) ratio was 0.91.

The compositions of the gas phase in the central region, in the near-wall region and at the outlet of the reactor were measured separately, and the corresponding results are presented in the table.

Example 12.

As illustrated in FIG. 5, in the fluidized bed reactor, the diameter was 9.0 m, the propylene injection rate was 9500 Nm ³ /h, the reaction temperature was 430°C, the reaction pressure was 0.04 MPa, and the ratio of propylene, ammonia and air was 1:1 ,2:9.6.

The air distribution plate 6 was a circular metal plate whose diameter was 9.0 m, the thickness was 16 mm, and the radius r of the central region was 7.92 m.

- 15 045132

The number of central holes was 29 per square meter of the central area, each of the central holes had a hole diameter D1 of 42 mm, and they were evenly spaced in a square shape with the distance between the holes being 197 mm, each of the central nozzle holes had a hole diameter d of 14.3 mm, and the inner diameter of D2 was 36 mm.

The number of peripheral holes was 20.5 per square meter of the peripheral area, the hole diameters D1' for the peripheral holes were 40 mm, respectively, the distance between adjacent peripheral holes was 197 mm, the hole diameters d' for the peripheral nozzle holes were 14.3 mm, respectively , and the inner diameter D2' was 34 mm.

The pressure drop APd of the air distribution plate was measured at full power of the device and was 88% of the pressure drop AP _b layer.

The D1/D1' ratio was 1.05, the d/d' ratio was 1, and the (d'/D1')/(d/D1) ratio was 1.05.

The compositions of the gas phase in the central region, in the near-wall region and at the outlet of the reactor were measured separately, and the corresponding results are presented in the table.

Example 13.

As illustrated in FIG. 5, in the fluidized bed reactor, the diameter was 9.0 m, the propylene injection rate was 9500 Nm ³ /h, the reaction temperature was 430°C, the reaction pressure was 0.04 MPa, and the ratio of propylene, ammonia and air was 1:1 ,2:9.6.

The air distribution plate 6 was a circular metal plate whose diameter was 9.0 m, the thickness was 16 mm, and the radius r of the central region was 7.92 m.

The number of central holes was 29 per square meter of the central area, each of the central holes had a hole diameter D1 of 42 mm, and they were evenly spaced in a square shape with the distance between the holes being 197 mm, each of the central nozzle holes had a hole diameter d of 14.9 mm, and the inner diameter of D2 was 36 mm.

The number of peripheral holes was 20.5 per square meter of the peripheral area, the hole diameters D1' for the peripheral holes were 40 mm, respectively, the distance between adjacent peripheral holes was 197 mm, the hole diameters d' for the peripheral nozzle holes were 14.9 mm, respectively , and the inner diameter D2' was 34 mm.

The pressure drop APd of the air distribution plate was measured at full power of the device and was 55% of the pressure drop APd, layer.

The D1/D1' ratio was 1.05, the d/d' ratio was 1, and the (d'/D1')/(d/D1) ratio was 1.05.

The compositions of the gas phase in the central region, in the near-wall region and at the outlet of the reactor were measured separately, and the corresponding results are presented in the table.

Example 14.

As illustrated in FIG. 5, in the fluidized bed reactor, the diameter was 9.0 m, the propylene injection rate was 9500 Nm ³ /h, the reaction temperature was 430°C, the reaction pressure was 0.04 MPa, and the ratio of propylene, ammonia and air was 1:1 ,2:9.6.

The air distribution plate 6 was a circular metal plate whose diameter was 9.0 m, the thickness was 16 mm, and the radius r of the central region was 7.92 m.

The number of central holes was 29 per square meter of the central area, each of the central holes had a hole diameter D1 of 42 mm, and they were evenly spaced in a square shape with the distance between the holes being 197 mm, each of the central nozzle holes had a hole diameter d of 14.6 mm, and the inner diameter of D2 was 36 mm.

The number of peripheral holes was 20.5 per square meter of the peripheral area, the hole diameters D1' for the peripheral holes were 40 mm, respectively, the distance between adjacent peripheral holes was 197 mm, the hole diameters d' for the peripheral nozzle holes were 14.6 mm, respectively , and the inner diameter D2' was 34 mm.

The pressure drop APd of the air distribution plate was measured at full power of the device and was 130% of the pressure drop APd, layer.

The D1/D1' ratio was 1.05, the d/d' ratio was 1, and the (d'/D1')/(d/D1) ratio was 1.05.

The compositions of the gas phase in the central region, in the near-wall region and at the outlet of the reactor were measured separately, and the corresponding results are presented in the table.

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Claims (24)

Central region Parietal region Reactor release Unreacted propylene, % Degree propylene conversion, % Yield of acrylonitrile after one pass, % Comparative example 1 1.6 2.3 97.8 79.5 Comparative example 2 1.4 2.5 97.7 79.3 Example 1 1.4 1.5 98.8 81.3 Example 2 1.4 1.8 98.5 80.7 Example 3 1.9 2.4 97.7 79.8 Example 4 1.8 2.3 97.8 79.9 Example 5 1.5 1.9 98.4 81.0 Example 6 1.5 2.5 98.3 80.2 Example 7 1.5 2.2 98.4 80.4 Example 8 1.4 1.5 98.8 81.3 Example 9 1.4 1.5 98.6 81.2 Example 10 1.8 2.5 97.7 79.8 Example 11 1.8 2.4 98.2 80.6 Example 12 1.4 1.5 98.8 81.3 Example 13 1.8 2.3 98.1 80.5 Example 14 1.5 1.9 98.4 81.0 As can be seen from the table, by using the gas distribution plate according to the present invention, the quality of fluidization of the catalyst near the reactor wall can be improved, and the conversion of propylene and the yield of acrylonitrile can also be significantly increased. CLAIM 1. A gas distribution plate, which is a metal plate containing holes located in the central region of the metal plate, called central holes, and holes located in the peripheral region of the metal plate, called peripheral holes, and the ratio D1/DT of the diameter D1 of the hole for the central hole to diameter D1' of the hole for the peripheral hole satisfies the expression 1.10 > D1/D1' > 1.01, the straight line distance between any point on the outer periphery of the metal plate and the central point of the metal plate being designated as R, the area surrounded by all points on metal plate at a distance r in a straight line from the central point is called the central region, and the region between the central region and the outer periphery is called the peripheral region, the value of r/R is from 0.7 to 0.85. 2. The gas distribution plate according to claim 1, wherein the gas distribution plate is an air distribution plate for a fluidized bed ammoxidation reactor, and/or said metal plate is a flat metal plate, and/or 1.06 > D1/D1' > 1.01. 3. The gas distribution plate according to claim 1, in which the diameters D1 of the holes for all central holes are the same or different from each other and independently amount to 16-60 mm, and/or the diameters D1' of the holes for all peripheral holes are the same or different from each other each other and independently amount to 15-58 mm. 4. The gas distribution plate according to claim 3, in which the diameters D1 of the holes for all central holes are the same or different from each other and independently amount to 22-52 mm, and/or the diameters D1' of the holes for all peripheral holes are the same or different from each other each other and independently amount to 21-50 mm. 5. The gas distribution plate according to claim 1, in which the number of central holes is from 16 to 100 per square meter of the central area, and/or the number of peripheral holes is from 2 to 50 per square meter of the peripheral area, and/or the number of central holes is from 70 to 99% relative to the total number of holes in the metal plate. 6. The gas distribution plate according to claim 5, in which the number of central holes is from 18 to 44 per square meter of the central region, and/or the number of peripheral holes is from 4 to 25 per square meter of the peripheral region, and/or the number of central holes is from 80 to 95% relative to the total number of holes in the metal plate. 7. The gas distribution plate according to claim 1, in which the number of central holes per unit area of the central region is almost the same. - 17045132 8. The gas distribution plate according to claim 1, in which the central holes and/or peripheral holes are arranged in a substantially square, equilateral triangle, equilateral rhombus or concentric circles. 9. The gas distribution plate according to claim 8, in which the central holes and/or peripheral holes are arranged in a substantially square or equilateral triangle shape. 10. The gas distribution plate according to claim 1, in which the distances between any two adjacent central holes are the same or different from each other, and in each case independently amount to 100-300 mm, and/or the distances between any two adjacent peripheral holes are the same or differ from each other, and in each case independently amount to 100-300 mm. 11. The gas distribution plate according to claim 10, in which the distances between any two adjacent central holes are the same or different from each other, and in each case independently amount to 150-270 mm, and/or the distances between any two adjacent peripheral holes are the same or differ from each other, and in each case independently amount to 150-270 mm. 12. The gas distribution plate according to claim 1, wherein the metal plate has a substantially circular shape, the circle having a diameter ranging from 5 to 29 m and a thickness ranging from 5 to 40 mm. 13. Gas distribution plate according to claim 12, in which the circle has a diameter ranging from 7 to 20 m, and/or the metal plate has a thickness ranging from 10 to 35 mm. 14. The gas distribution plate according to claim 1, wherein at least one of the central holes has a nozzle, called a central nozzle, wherein the central nozzle is a hollow pipe, and the head end of the central nozzle is inserted into the central hole, perpendicularly connected to the metal plate and is located coaxially with the central opening, and the tail end of the central nozzle has an opening called the central nozzle opening, and/or at least one of the peripheral openings has a nozzle called the peripheral nozzle, wherein the peripheral nozzle is a hollow pipe, and wherein a head end of the peripheral nozzle is inserted into the peripheral hole, attached perpendicularly to the metal plate and positioned coaxially with the peripheral hole, and a tail end of the peripheral nozzle has an opening called a peripheral nozzle hole. 15. The gas distribution plate according to claim 14, in which all the central holes have the specified nozzle, and/or all the peripheral holes have the specified nozzle. 16. The gas distribution plate according to claim 14, in which the diameters d' of the holes for all holes of the central nozzles are the same or different from each other and independently range from 5 to 20 mm, and/or the diameters d' of the holes for all holes of the peripheral nozzles are the same or differ from each other and are independently from 5 to 20 mm, and/or the hole diameter d for the central nozzle hole is identical or different from the hole diameter d' for the peripheral nozzle hole, and/or d/d' satisfies the expression 1.10 > d/d' > 1.00. 17. The gas distribution plate according to claim 16, in which the diameters d' of the holes for all holes of the central nozzles are the same or different from each other and independently range from 10 to 16 mm, and/or the diameters d' of the holes for all holes of the peripheral nozzles are the same or differ from each other and independently range from 10 to 16 mm, and/or d/d' satisfies the expression 1.04 > d/d' > 1.00. 18. The gas distribution plate according to claim 16, in which the central nozzles and/or peripheral nozzles have an injection angle α ranging from 2 to 20°. 19. Gas distribution plate according to claim 16, in which the length of the central nozzle and/or peripheral nozzle is 80-300 mm. 20. The gas distribution plate according to claim 14, wherein the opening diameter of the central nozzle opening is designated as d, the opening diameter of the peripheral nozzle opening is designated as d', the opening diameter of the central opening is designated as D1, and the opening diameter of the peripheral opening is designated as D1 ', (d'/D1')/(d/D1)=1-1.25. 21. Gas distribution plate according to claim 20, in which (d'/D1')/(d/D1)=1.01-1.10. 22. The gas distribution plate according to claim 14, in which the internal diameters D2 of all central nozzles are the same or different from each other and independently range from 6 to 50 mm, and/or the internal diameters D2' of all peripheral nozzles are the same or different from each other and independently range from 5 to 48 mm. 23. The gas distribution plate according to claim 22, in which the internal diameters D2 of all central nozzles are the same or different from each other and independently range from 12 to 44 mm, and/or the internal diameters D2' of all peripheral nozzles are the same or different from each other and independently range from 11 to 42 mm. 24. Gas distribution plate, which is a metal plate containing a -