CN116236978B - Gas distributor and gas-solid reactor comprising same - Google Patents

Abstract

The invention belongs to the field of chemical equipment, and specifically relates to a gas distributor and a gas-solid reactor containing the same. The gas distributor includes a gradually expanding component and a distribution plate component that are arranged sequentially along the gas flow direction. The gradually expanding component includes a double-layer dispersion cover. There is a first gas channel between the inner and outer dispersion covers. The inside of the inner dispersion cover is connected to the first gas channel. The cross-sectional area of the second gas channel connected by the gas channel gradually increases along the gas flow direction; the distribution plate assembly includes at least two parallel and spaced gas distribution plates, and the distance between two adjacent gas distribution plates is Δh satisfy: Ch _h is the gas jet convergence coefficient, which takes 0.02~0.1m·s, is the average gas flow velocity at the distributor outlet section, in m/s, and φ is the porosity of the gas distribution plate. The invention can improve the uniformity of outlet gas distribution and has good universal applicability, and can be widely used in reactors with various diameter ranges, and is especially suitable for large-diameter reactors.

Description

A gas distributor and a gas-solid reactor containing the same

Technical field

The invention belongs to the technical field of chemical equipment, and specifically relates to a gas distributor, especially a multi-stage diffusion deceleration gas distributor that can be used in large reactors, and a gas-solid reactor including the gas distributor.

Background technique

Various continuous catalytic reaction processes such as catalytic oxidation, catalytic hydrogenation, catalytic dehydration, and hydroamination technology have the advantages of high efficiency, energy saving, environmental protection, and easy control, and are widely used in chemical production. At this stage, my country's chemical industry structure is accelerating the upgrading of equipment and intelligent production, and the annual output requirements of various gas-solid reactors in the chemical industry are increasing. After the raw material gas enters the gas-solid reactor, a chemical reaction occurs in the catalyst reaction layer and corresponding chemical products are produced. A key factor in the above reaction process is the uniformity of the distribution of the raw material gas when entering the catalyst reaction layer. The gas flow rate of the unevenly distributed raw gas entering the downstream tubular, fixed-bed and other structural reactors is uneven, which causes the catalyst load to be uneven after the reactor is enlarged, that is, the space velocity varies greatly, resulting in target selectivity, The raw material conversion rate and product yield were significantly reduced.

When the diameter of the reactor is small, the raw material gas will gradually be evenly distributed due to free diffusion during the flow process. At this time, after preliminary treatment by a simple air inlet device, the gas distribution can be made more even to meet engineering needs. However, as the annual output requirements of chemical plants become larger and larger, the diameter of the reactor is also getting larger and larger. The gas diffusion during the flow process will not be able to meet the gas uniformity requirements. This characteristic is not suitable for large-scale production. The performance is particularly obvious in diameter reactors. This is the so-called "amplification effect". It is this effect that causes many reactor projects to fail to reach production or fail to reproduce pilot test results during the scale-up process. For example, the diameter of the catalytic oxidation reactor used in an acetaldehyde production line with an annual output of 20,000 tons is 2m, while the diameter of the catalytic oxidation reactor used in an acetaldehyde production line with an annual output of 100,000 tons can reach 4m. The diameter of the catalytic dehydrogenation reactor for alcohol gas phase dehydrogenation to butyrolactone has reached 5 to 6 meters. If the reactor with an annual output of 100,000 tons only uses the gas distribution method of the reactor with an annual output of 20,000 tons, the production line will not be able to reach Production, and even the production line cannot be started, causing immeasurable economic losses. Therefore, for large-diameter reactors with high productivity, it is necessary to configure special gas distribution devices.

The gas distributor is a device that distributes gas evenly and is an important component of high-capacity large-diameter reactors. The gas distributor is usually installed at the front end of the catalyst reaction layer in the reactor to evenly distribute the raw gas so that the flow of raw gas entering the catalyst reaction layer is uniform. Chinese patent document CN105597655A discloses a gas distributor, which includes a transition section and one or several distribution plates arranged inside. Several distribution plates are arranged at intervals along the gas flow direction, and the edge of each distribution plate is connected to the inner wall of the transition section. , and there are several through holes on the distribution board. Another Chinese patent document CN103619465A discloses a gas distributor including a gas distribution plate and a truncated cone-shaped side wall. The gas distribution plate has a through hole. The upper end of the distributor side wall is connected to the gas inlet of the reactor, and the lower end is connected to the gas distribution port. Peripheral connections of boards. Although the above-mentioned prior art all claims to achieve uniform flow when the gas flows out of the distributor, in fact, since the distribution plate is arranged in the inner cavity of the transition section (side wall of the distributor), the center of the gas flowing through the transition section is The regional gas mainstream velocity is very large, that is, the velocity component in the same direction as the main gas flow in the distributor is very large, resulting in severe backflow in the outer circle area below the distribution plate (CN103619465A has a smaller degree of backflow), reducing the uniformity of gas distribution. sex.

It can be seen that there is still a lot of room for improvement in the distribution effect of existing gas distributors. In addition, the distributors in the prior art basically only provide relatively preferred structural dimensions that limit chemical reaction engineering and/or limited production capacity, and the sizes vary greatly, and the structural parameters of the distributor, such as the number of different distribution plates, are not systematically considered. , through hole diameter, distribution plate spacing, etc. affect the gas distribution effect, so the existing distributor has poor application scalability. Moreover, the distributors in the prior art do not consider the influence of epitaxial bases such as inlet pipe diameter, inlet flow rate, etc. on the gas distribution effect. In fact, even the same distributor in the project will be affected by differences in design regulations and on-site piping. Due to the influence of methods, etc., the gas distribution effects in different factories also vary greatly.

Contents of the invention

In view of this, the technical problem to be solved by the present invention is that the distribution effect of the existing gas distributor is greatly affected by the epitaxial structure or process conditions and the outlet gas distribution is uneven, and then by optimizing the structure of the gas distributor, it provides an almost indispensable gas distributor. Affected by the epitaxial structure or process conditions, the gas-solid gas distributor can distribute the gas evenly and is suitable for large reactors.

In order to achieve the above objects, the present invention provides the following technical solutions:

According to an embodiment of the present invention, in a first aspect, the present invention provides a gas distributor, including:

The gradually expanding assembly includes a first gas dispersion cover and a second gas dispersion cover located inside the first gas dispersion cover. The second gas dispersion cover has a gas inlet and a gas outlet. Between the gas inlet and the gas A second gas channel is formed between the outlets, and the cross-sectional area of the second gas channel gradually increases along the gas flow direction; the inlet pipe of the reaction raw material gas is arranged on the first gas dispersion cover close to the second gas At the gas outlet of the dispersion cover, the space between the first gas dispersion cover and the second gas dispersion cover forms a first gas channel, and the first gas channel is connected with the second gas channel; and

The distribution plate assembly includes at least two parallel and spaced gas distribution plates. The gas distribution plates are provided with a number of through holes. The distance Δh between two adjacent gas distribution plates satisfies:

Among them, Ch _h is the gas jet convergence coefficient, which in the present invention refers to the correction coefficient on the influence range of the gas passing through the through-hole jet, the unit is m·s, and the value is 0.02 to 0.1; is the average gas flow velocity at the outlet section of the gas distributor, in m/s; φ is the porosity of the gas distribution plate; Δh is in mm;

The gradually expanding component and the distribution plate component are arranged sequentially along the gas flow direction, and the maximum cross-sectional area of the second gas channel is not less than the area of the gas distribution plate.

In the embodiment of the present invention, the gas distribution plate is circular, and its diameter D ₀ satisfies: Among them, Q is the gas volume flow rate flowing through the gas reactor, the unit is m ³ /h; π is the pi ratio, the value is 3.1415926; D ₀ unit is mm.

In an embodiment of the present invention, the average gas flow velocity u at the outlet section of the gas distributor is 0.1 to 2.5 m/s.

In an embodiment of the present invention, the porosity φ of the gas distribution plate ranges from 0.3 to 0.5.

In the embodiment of the present invention, the through holes are arranged staggered at 60° on the gas distribution plate, the through holes are round holes, and the hole center distance d of two adjacent through holes satisfies: Among them, D ₃ is the diameter of the through hole, the unit is mm, and the value is 0.01 to 0.03D ₀ , D ₀ is the diameter of the gas distribution plate; φ is the porosity of the gas distribution plate, and the value is 0.3 to 0.5; π is pi, and its value is 3.1415926.

In an embodiment of the present invention, the shape of the through hole is a triangle, a square, a rectangle, a rhombus, a cross, a hexagon or an ellipse.

In an embodiment of the present invention, the through holes are arranged in concentric circles, straight rows or staggered rows.

In an embodiment of the present invention, the number of the gas distribution plates is 3 to 6.

In an embodiment of the present invention, the gas distribution plate is arranged perpendicular to the gas flow direction.

In an embodiment of the present invention, the distribution plate assembly further includes a first cylinder, the peripheral edge of the gas distribution plate is connected to the inner wall of the first cylinder, and the internal space of the first cylinder forms a third cylinder. Gas channel, the third gas channel is connected with the second gas channel.

In an embodiment of the present invention, the angle α between the cross section of the second gas dispersion cover and the second gas channel is 30° to 70°, preferably 45° to 65°.

In an embodiment of the present invention, the height _H2 of the second gas dispersion cover satisfies: Among them, B _h is the height coefficient of the second gas dispersion hood, which is 0.5 to 0.8; D ₀ is the diameter of the gas distribution plate (as mentioned above), in mm; α is the second gas dispersion hood and the second gas channel The angle between the cross sections is 30 to 70°, preferably 45 to 65°.

In an embodiment of the present invention, the distance between the top of the first gas dispersion hood and the gas inlet of the second gas dispersion hood is not less than 0.25D ₀ , where D ₀ is the diameter of the gas distribution plate (as mentioned above (described above), the unit is mm.

In an embodiment of the present invention, there is at least one inlet pipe. When there are more than two inlet pipes, the inlet pipes are symmetrically arranged on the outer wall of the first gas dispersion cover.

In an embodiment of the present invention, the diameter D _inlet or the equivalent diameter _De of the inlet pipe is 0.1 to 0.2D ₀ , where D ₀ is the diameter of the gas distribution plate (as mentioned above), and the unit is mm.

In the embodiment of the present invention, the length L _inlet of the inlet pipe is 1.0 to 2.0 D _inlet , where D _inlet is the diameter of the inlet pipe (as mentioned above), and the unit is mm.

In an embodiment of the present invention, the distance h _inlet between the inlet pipe and the bottom surface of the first gas dispersion cover is 0 to 900 mm.

According to an embodiment of the present invention, in a second aspect, the present invention also provides a gas-solid reactor, including the above gas distributor.

Compared with the existing technology, the technical solution of the present invention has the following advantages:

1. The gas distributor provided by the embodiment of the present invention includes a gradually expanding component and a distribution plate component that are arranged sequentially along the gas flow direction. The gradually expanding component includes a first gas dispersion cover and a second gas dispersion cover located inside it. The gas dispersion hood has a gas inlet and a gas outlet. A second gas channel is formed between the gas inlet and the gas outlet of the second gas dispersion hood. The cross-sectional area of the second gas channel gradually increases along the gas flow direction; the reaction raw material gas The inlet pipe is arranged on the first gas dispersion cover close to the gas outlet of the second gas dispersion cover. The space between the first gas dispersion cover and the second gas dispersion cover forms a first gas channel, and the first gas channel and the second gas dispersion cover form a first gas channel. The gas channels are connected; the distribution plate assembly includes at least two parallel and spaced gas distribution plates. A number of through holes are provided on the gas distribution plate. The distance Δh (unit: mm) between two adjacent gas distribution plates satisfies: Among them, C _h is the gas jet convergence coefficient, the unit is m·s, the value is 0.02~0.1,/> is the average gas flow velocity at the outlet section of the gas distributor, in m/s, and φ is the porosity of the gas distribution plate. As a result, after the gas enters the distributor, it is blocked by the wall surface of the second gas dispersion cover in the first gas channel, flows and gathers along the outer wall of the second gas dispersion cover toward the gas inlet of the second gas dispersion cover, thereby realizing the gas The first-stage diffusion rectification; then, the gas enters the second gas channel. As the flow area gradually increases, the main flow velocity of the gas in the central area gradually decreases, and the gas achieves the second-stage deceleration pre-distribution; by gradually expanding the component It is set up separately from the distribution plate assembly, and the two are connected sequentially, so that after the gas flows from the gradually expanding assembly into the distribution plate assembly, under the action of the multi-layer porous structure of the gas distribution plate, on the one hand, due to the throttling resistance, the air flow is made radially uniform , on the other hand, due to the through-hole throttling effect to form a gas jet, each jet gas passing through multiple through-holes will gather under the gas distribution plate to form a convergence area. When the distribution plate spacing Δh meets the above conditions, it can ensure that the convergence area has Enough space allows the gas jets to entrain and interfere with each other, promoting the third-level throttling main distribution of gas. The gas is sequentially distributed through the above three levels of "diffusion rectification" - "deceleration pre-distribution" - "throttle main distribution", which can further improve the uniformity of gas distribution at the distributor outlet. At the same time, due to the "diffusion rectification" effect, it can also eliminate The influence of the structural parameters (diameter, length, height) of the inlet pipeline and the gas flow rate distribution at the inlet of the distributor on the performance of the distributor greatly improves the universality of the distributor, making the gas distributor of the present invention widely used in various types of applications. Reactors in a wide range of diameters, especially suitable for large diameter reactors, all have good gas uniform distribution effects.

2. The gas distributor provided by the embodiment of the present invention is the first to propose a systematic and complete design idea for various structural parameters of the gas distributor, obtain rational and scientific calculation formulas, and realize the key structural parameters of the distributor such as gas distribution. The plate diameter, through hole diameter, hole center distance, second gas dispersion cover height, etc. are accurately set, and the above structural parameter settings are universal and can be applied to reactors with various diameter ranges.

3. The gas distributor provided by the embodiment of the present invention has a simple structure and can be embedded in an existing reactor as a whole, or can be split into multiple components and installed in the existing reactor respectively. There is no need to modify the structure or assembly of the existing reactor. Convenient and low cost.

It can be seen that the present invention provides a gas distributor for reactors with good gas distribution effect, wide application range, easy construction and renovation implementation, and can meet the uniform gas distribution requirements of reactors in various diameter ranges, especially large reactors. , has great engineering value.

Description of the drawings

In order to more clearly explain the specific embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings that need to be used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings in the following description The drawings illustrate some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without exerting any creative effort.

Figure 1 is a schematic structural diagram of the gas distributor provided in Embodiment 1.

Figure 2 is a cross-sectional view of Figure 1.

The reference numbers in Figures 1 and 2 are explained as follows:

1-Inlet pipe, 2-First gas dispersion cover, 21-Head, 22-Second cylinder, 3-Second gas dispersion cover, 31-Gas inlet, 32-Gas outlet, 4-Gas distribution plate, 5 -First cylinder, 6-distributor outlet.

Figure 3 is a schematic diagram of the layout of the distribution plate through holes in Figure 1.

Figure 4a is a schematic diagram of the gas distribution principle of the gas distributor shown in Figure 1 (front view cross-section).

Figure 4b is a schematic diagram of the gas distribution principle of the gas distributor shown in Figure 1 (side view cross-section).

Figure 5 is a diagram showing the variation of gas unevenness at the outlet of the distributor in Embodiment 1 with the average flow rate of the gas at the outlet cross-section.

Figure 6 is a diagram showing the variation of the gas unevenness at the distributor outlet according to the angle α of the second gas dispersion cover in Embodiment 1.

Figure 7 is a diagram showing the variation of the gas unevenness at the distributor outlet in Embodiment 1 with the ratio of the height of the second gas dispersion cover to the corresponding cone height.

Figure 8 is a graph showing the variation of the gas unevenness at the distributor outlet according to the diameter of the through hole of the distribution plate in Embodiment 1.

Figure 9 is a diagram showing the variation of gas unevenness at the distributor outlet with the porosity of the distribution plate in Embodiment 1.

Figure 10 is a diagram showing the variation of gas unevenness at the distributor outlet in Embodiment 1 with the spacing between distribution plates.

Figure 11 is a graph showing the variation of gas unevenness at the distributor outlet in Embodiment 1 with the number of distribution plates.

Figure 12 is a graph showing the variation of gas unevenness at the outlet of the distributor in Embodiment 1 with the diameter of the inlet pipe.

Figure 13 is a graph of the outlet velocity of the distributor in Embodiment 1.

Figure 14 is a graph of the outlet velocity of the distributor in Embodiment 2.

Figure 15 is a graph of the outlet velocity of the distributor in Embodiment 3.

Figure 16 is a graph of the outlet velocity of the distributor in Embodiment 4.

Figure 17a is the reactor gas velocity distribution cloud diagram of Comparative Example 1 (mainstream velocity range -1.34~28.64m/s).

Figure 17b is the reactor gas velocity distribution cloud diagram of Comparative Example 1 (mainstream velocity range of 0~28.64m/s).

Figure 18a shows the distribution cloud diagram of the distributor outlet velocity in Comparative Example 2 (main stream velocity range of -0.34~2.27m/s).

Figure 18b shows the distribution cloud diagram of the distributor outlet velocity in Comparative Example 2 (mainstream velocity range of 0~2.27m/s).

Figure 19 is a schematic structural diagram of the gas distributor provided in Comparative Example 3.

Figure 20 is a cloud diagram of the distributor outlet velocity distribution in Comparative Example 3.

Figure 21a is a cloud diagram of the distributor outlet velocity distribution of Comparative Example 4 (mainstream velocity range of -0.15~2.33m/s).

Figure 21b is a cloud diagram of the distributor outlet velocity distribution of Comparative Example 4 (main stream velocity range of 0~2.33m/s).

Figure 22a is a cloud diagram of the distributor outlet velocity distribution of Comparative Example 5 (main stream velocity range of -0.1.6~2.52m/s).

Figure 22b is a cloud diagram of the distributor outlet velocity distribution of Comparative Example 5 (mainstream velocity range of 0~2.52m/s).

Figure 23a is a cloud diagram of the distributor outlet velocity distribution of Comparative Example 6 (main flow velocity range -1.67~5.66m/s).

Figure 23b is a cloud diagram of the distributor outlet velocity distribution of Comparative Example 6 (mainstream velocity range of 0~5.66m/s).

Figure 24 is a cloud diagram of the outlet gas velocity distribution of the sparger of Comparative Example 7 when the average outlet flow rate is 0.1m/s.

Figure 25a is a cloud diagram of the outlet gas velocity distribution of the sparger of Comparative Example 7 when the average outlet flow velocity is 1m/s (mainstream velocity range of -0.5~3.24m/s).

Figure 25b is a cloud diagram of the outlet gas velocity distribution of the sparger of Comparative Example 7 when the average outlet flow velocity is 1 m/s (main stream velocity range of 0 to 3.24 m/s).

Figure 26a is a cloud diagram of the outlet gas velocity distribution of the sparger of Comparative Example 7 when the average outlet flow velocity is 3m/s (mainstream velocity range -1.25~9.27m/s).

Figure 26b is a cloud diagram of the outlet gas velocity distribution of the sparger of Comparative Example 7 when the average outlet flow velocity is 3m/s (mainstream velocity range of 0~9.27m/s).

Figure 27a is a cloud diagram of the outlet gas velocity distribution of the sparger of Comparative Example 7 when the average outlet flow velocity is 7m/s (mainstream velocity range -3.06~21.9m/s).

Figure 27b is a cloud diagram of the outlet gas velocity distribution of the sparger of Comparative Example 7 when the average outlet flow velocity is 7m/s (mainstream velocity range of 0~21.9m/s).

Figure 28 is a graph showing the variation of the gas unevenness at the outlet of the distributor of Comparative Example 7 with the outlet average flow rate.

Figure 29a shows the outlet gas velocity distribution cloud diagram of the sparger of Comparative Example 8 when the inlet pipe diameter is 130mm (main flow velocity range -0.54~4.76m/s).

Figure 29b shows the outlet gas velocity distribution cloud diagram of the sparger of Comparative Example 8 when the inlet pipe diameter is 130mm (main stream velocity range of 0~4.76m/s).

Figure 30a is a cloud diagram of the outlet gas velocity distribution of the sparger of Comparative Example 8 when the inlet pipe diameter is 283mm (main flow velocity range -0.36~3.43m/s).

Figure 30b is a cloud diagram of the outlet gas velocity distribution of the sparger of Comparative Example 8 when the inlet pipe diameter is 283mm (main stream velocity range of 0~3.43m/s).

Figure 31 is a cloud diagram of the outlet gas velocity distribution of the sparger of Comparative Example 8 when the inlet pipe diameter is 566mm.

Figure 32 is a cloud diagram of the outlet gas velocity distribution of the sparger of Comparative Example 8 when the inlet pipe diameter is 849mm.

Figure 33 is a diagram showing the variation of the gas unevenness at the distributor outlet with the diameter of the inlet pipe of Comparative Example 8.

Detailed ways

The following examples are provided to better understand the present invention. They are not limited to the best embodiments and do not limit the content and protection scope of the present invention. Anyone who is inspired by the present invention or uses the present invention to Any product that is identical or similar to the present invention by combining it with other features of the prior art falls within the protection scope of the present invention.

If no specific experimental steps or conditions are specified in the examples, the procedures can be carried out according to the conventional experimental steps or conditions described in literature in the field. If the manufacturer of the reagents or instruments used is not indicated, they are all conventional reagent products that can be purchased commercially.

It should be noted that in the present invention, "the through holes are staggered at 60° on the gas distribution plate" means that the through holes on the gas distribution plate are not located around the outermost through holes (ie, 360 degrees). °) There are six through holes evenly distributed. The terms "distributor" and "gas distributor" are the same concept, "dispersion hood" and "gas distribution hood" are the same concept, and "distribution plate" and "gas distribution plate" are the same concept. The same parameter symbol has the same meaning in the present invention.

In order to quantitatively evaluate the distribution effect of the gas distributor, the present invention defines the gas unevenness σ at the distributor outlet, and its calculation method is: In this formula, M is the number of discrete points in the sparger outlet section, u _i is the mainstream velocity at each discrete point in the sparger outlet section, that is, the velocity component in the same direction as the main flow of the gas in the sparger, /> is the average gas flow velocity at the distributor outlet section, and Σ is the cumulative summation calculation symbol. According to the physical meaning of this formula, the smaller the value of gas unevenness σ at the outlet of the distributor, the more uniform the gas distribution will be, and the more chemical reaction efficiency can be improved. When the gas is completely uniformly distributed, the gas non-uniformity σ value at the distributor outlet is zero, which is an ideal distribution state. However, in reality, when the gas non-uniformity σ value at the distributor outlet is not greater than 0.4, the gas is basically close to uniform. distribution, and the smaller the σ value, the better. Therefore, the present invention recommends that the gas non-uniformity σ value at the outlet of the distributor be no more than 0.4 as a quantitative evaluation standard for chemical reaction production.

In the chemical production process, the raw material gas enters the catalytic reactor through the air inlet pipe. After being evenly distributed in the reactor through the distributor, it enters the catalyst reaction layer to participate in chemical reactions. A key factor in this reaction process is the uniformity of the distribution of the feed gas when entering the catalyst reaction layer. When the diameter of the reactor is large, the uniform distribution effect of the distributor is significantly reduced due to the "amplification effect", making it difficult to meet the engineering gas distribution uniformity requirements. In order to solve this technical problem, the present invention pioneered the multi-level distribution idea of "expansion rectification"-"deceleration pre-distribution"-"throttle main distribution", and invented the "double-layer dispersion cover-multi-layer distribution" "plate" is the main body of the multi-stage diffusion deceleration gas distributor. This gas distributor can not only meet the requirements for uniform gas distribution in large chemical reactors, but also eliminate the impact of the structural parameters of the inlet pipeline and the flow rate distribution of the inlet gas on the distributor performance. The influence greatly improves the universality of the distributor, so that the gas distributor of the present invention can be widely used in reactors with various diameter ranges, and is especially suitable for large-diameter reactors.

According to an embodiment of the present invention, the gas distributor provided by the present invention includes:

The gradually expanding assembly includes a first gas dispersion cover and a second gas dispersion cover located inside the first gas dispersion cover. The second gas dispersion cover has a gas inlet and a gas outlet. Between the gas inlet and the gas A second gas channel is formed between the outlets, and the cross-sectional area of the second gas channel gradually increases along the gas flow direction; the inlet pipe of the reaction raw material gas is arranged on the first gas dispersion cover close to the second gas At the gas outlet of the dispersion cover, the space between the first gas dispersion cover and the second gas dispersion cover forms a first gas channel, and the first gas channel is connected with the second gas channel; and

The distribution plate assembly includes at least two parallel and spaced gas distribution plates. The gas distribution plates are provided with a number of through holes. The distance Δh (unit mm) between two adjacent gas distribution plates satisfies:

Among them, Ch _h is the gas jet convergence coefficient. In the present invention, it refers to the correction coefficient on the influence range of the gas passing through the through-hole jet. The unit is m·s and the value is 0.02~0.1. is the average gas flow velocity at the outlet section of the gas distributor, in m/s, and φ is the porosity of the gas distribution plate;

The gradually expanding component and the distribution plate component are arranged sequentially along the gas flow direction, and the maximum cross-sectional area of the second gas channel is not less than the area of the gas distribution plate.

In the gradually expanding assembly of the present invention, the cross-sectional areas of the first gas channel and the second gas channel gradually increase along the gas flow direction, which makes the gas enter the first gas channel from the inlet pipe. As the gas flows, the gas The dynamic pressure decreases and the static pressure increases, achieving diffusion and rectification of the gas. Then the gas enters the second gas channel, its dynamic pressure further decreases, and the static pressure further increases, achieving deceleration and pre-distribution of the gas.

The inventor found through research that the existing technology directly arranges the distribution plate in the dispersion cover (corresponding to the "second gas channel" in the present invention). Since the main flow velocity of the gas in the central area is very large, the outer circular area below the distribution plate will be Severe backflow occurs, which reduces the efficiency of the distribution plate. Therefore, the present invention is the first to set up a double-layer dispersion cover and set it separately from the distribution plate assembly. The two are connected in sequence, so that after the gas enters the distributor, the first gas The channel is blocked by the wall of the second gas dispersion hood, flows and gathers along the outer wall of the second gas dispersion hood toward the gas inlet of the second gas dispersion hood, realizing the first-stage diffusion rectification of the gas; subsequently, the gas enters the second gas dispersion hood. In the second gas channel, as the circulation area gradually increases, the main flow velocity of the gas in the central area gradually decreases, and the gas realizes the second-stage deceleration pre-distribution; by setting the double-layer dispersion cover (gradual expansion component) and the distribution plate component separately, The two are connected sequentially, so that after the gas flows from the gradually expanding component into the distribution plate component, under the action of the gas distribution plate with a multi-layer porous structure, on the one hand due to the throttling resistance, the air flow is made radially uniform, and on the other hand due to the through holes The throttling effect forms a gas jet. Each jet gas passing through multiple through holes will gather under the gas distribution plate to form a convergence area. When the distribution plate spacing Δh meets the above conditions, it can ensure that the convergence area has enough space for each strand of gas. The jets entrain and interfere with each other, promoting the main distribution of gas to achieve throttling, thereby effectively improving the uniformity of gas distribution at the outlet of the distributor. At the same time, due to the "diffusion rectification" effect, the structural parameters of the inlet pipe (diameter, length, height) and the influence of the gas flow rate distribution at the sparger inlet on the performance of the sparger, which greatly improves the universality of the sparger, so that the gas sparger of the present invention can be widely used in reactors with various diameter ranges, especially suitable for large-scale reactors. diameter reactors, all have good gas uniform distribution effects.

In the embodiment of the present invention, multi-layer distribution plates are arranged starting from the gas outlet of the second gas dispersion hood, and the spacing between the distribution plates is a key parameter, which determines the length of the distribution plate assembly. According to common sense, the greater the number of distribution plates, the more even the air velocity distribution will be. However, after research, the inventor surprisingly found that only when the distribution plate spacing is within a reasonable range, the more distribution plates are arranged, the more uniform the airflow distribution can be achieved. When the spacing between distribution plates is small, the distribution plate "short circuit" phenomenon will occur and the function of the distribution plate will fail. At this time, under a certain length limit of the distribution plate components, increasing the number of distribution plates will reduce the uniformity of gas distribution. The possible explanation for this phenomenon is: when the distance between the distribution plates is small and the flow rate of the gas flowing through the through holes of the distribution plate is high, the gas will directly pass through the lower distribution plate and cannot form a convergence area under the distribution plate. At this time, the gas flow The flow situation through two-layer distribution plates is similar to that through a single-layer distribution plate, that is, the lower distribution plate does not work and its function fails. At this time, the multi-layer distribution plate with a small distance is only equivalent to one layer of distribution plate. According to calculation research Based on engineering experience, it is difficult to achieve uniform gas distribution with one layer of distribution plate. A short circuit of the distribution plate will significantly reduce the production capacity of the reactor. Reasonably increasing the spacing between the distribution plates can avoid the "short circuit" phenomenon of the distribution plates. However, when the distance between distribution boards is large, the overall length of the distribution board components will be longer, which is not conducive to actual production line construction. Through the above analysis, the present invention believes that the distance Δh (unit mm) between two adjacent gas distribution plates should satisfy: Among them/> is the average flow rate of gas at the outlet section of the gas distributor, in m/s, with a value of 0.1 to 2.5; φ is the porosity of the gas distribution plate, with a value of 0.3 to 0.5. Through theoretical analysis and practical engineering experience, the inventor suggests The value of the gas jet convergence coefficient _Ch is 0.02 to 0.1. And considering the actual construction and installation, the absolute height value of the distribution plate spacing should be greater than 100mm.

On the basis of reasonable distribution plate spacing, the greater the number of distribution plates, the better the gas distribution effect. However, research has found that when the number of distribution plates is greater than 4, the increase in the number of distribution plates has limited improvement in the uniformity of air flow velocity distribution; at the same time, when the number of distribution plates is greater than 6, the overall length of the distribution plate assembly will be longer, which is not conducive to the actual production line. construction. Considering the actual construction and production of chemical industry, the number of distribution plates in the present invention is at least 2 layers, preferably 3 to 6 layers.

In some embodiments of the present invention, the gas distribution plate is circular, and its diameter D ₀ (unit mm) satisfies: Among them, Q is the gas volume flow rate flowing through the gas reactor, the unit is m ³ /h, π is the pi ratio, the value is 3.1415926,/> It is the average gas flow velocity at the outlet section of the gas distributor, the unit is m/s, and the value is 0.1 to 2.5. It should be noted here that, to facilitate calculation and construction, the gas distribution plate diameter D ₀ , the gas outlet cross-sectional diameter of the second gas dispersion hood, and the bottom diameter of the first gas dispersion hood are all the same, collectively referred to as the distributor diameter. The diameter of the distributor is mainly determined by the production scale requirements and the gas flow rate under the design process conditions. The main constraints on the diameter of the distributor are: (a) The gas passes through the gas distributor to form a uniformly distributed gas flow, enters the catalyst reaction layer in the reactor, and participates in chemical reactions under the action of the catalyst. A uniform and larger flow rate can strengthen the reaction The mass transfer and heat transfer process in the reactor; (b) A larger flow rate is conducive to increasing the production load of the reactor and increasing the production capacity. Generally, the gas flow rate is required to be greater than 0.1m/s; (c) The gas flow rate should also meet the requirements of the chemical reaction process demand, excessive flow rate will result in the residence time of the raw material gas in the catalytic layer being too short, and the chemical reaction will be insufficient. The upper limit of the reactor flow rate is limited by the type of chemical reaction; (d) In particular, for gas-solid phase reactions , the upper limit of the gas flow rate is also limited by the pressure drop of the reactor. If the gas flow rate is too large, the pressure drop after flowing through the catalytic layer will be too large, and it will not be able to meet the downstream production needs. For example, according to the reactor pressure drop correlation formula proposed by Ergun in 1952 , the pressure drop is related to the square of the flow rate. Therefore, for most existing reactors, the average flow velocity of the gas entering the catalyst bed is generally lower than 2.5m/s, and it is extremely rare for a velocity of more than 5m/s to occur. Under the above constraints, in large gas-solid reactors, the average flow rate of gas entering the catalyst reaction layer is generally required to be 0.1 to 2.5 m/s.

The design of distribution plate structures in the prior art is often based on specific engineering problems and is determined based on experience. Currently, no design methods or standards have been disclosed, making it difficult to expand or transfer the optimal values given in existing literature to other working conditions. In engineering, it is not conducive to engineering applications. For the distributor used in the large-scale gas-solid reactor involved in the present invention, there is no published design method or standard. Therefore, the present invention systematically studies the influence of the distribution plate structure on the gas distribution effect, and formulates corresponding optimal parameters.

The thickness of the gas distribution plate is not limited in the present invention. It is well known in the art that the thickness of the gas distribution plate should meet the mechanical strength required by the gas flow rate. Moreover, the invention does not specifically limit the shape and arrangement of the through holes on the gas distribution plate. Any shape in the prior art (such as triangle, square, rectangle, rhombus, cross, hexagon or ellipse) And/or arrangement (such as common straight arrangement, staggered arrangement or concentric circle arrangement) through holes are suitable for the present invention. As an example, in some embodiments of the present invention, the distribution plate is arranged perpendicular to the direction of gas flow, and the distribution plate structure is designed as a circular plate with staggered circular through holes. In order to facilitate the processing of circular through holes, it is preferred that the thickness H ₃ of the distribution plate is less than 10 mm, and the circular through holes on the distribution plate are arranged in a staggered manner at 60 degrees. After extensive research, the inventor found that the diameter of the circular through hole of the distribution plate has the following effects on gas distribution: (1) When the diameter of the circular through hole is less than 0.01D ₀ , the diameter of the circular through hole is smaller, and the gas flows through the through hole. Strong jet flow is easily formed behind the hole, and the gas distribution effect becomes worse. The uniformity of gas at the distributor outlet decreases as the diameter of the circular through hole decreases; (2) When the diameter of the circular through hole is 0.01D ₀ ~ 0.04D ₀ , The diameter of the circular through hole is relatively reasonable, and the gas will produce a suitable throttling effect through the circular through hole. The gas will gather under the distribution plate to form a reasonable convergence area. The gas jets in the convergence area will entrain and interfere with each other. The gas distribution effect will be better and the distribution will be better. The gas uniformity at the outlet of the device is relatively stable within this interval; (3) When the diameter of the circular through hole is greater than 0.04D ₀ , the diameter of the circular through hole is larger, and the gas cannot form an effective throttling effect after flowing through the through hole. The distribution effect is poor, and the uniformity of gas at the distributor outlet decreases as the diameter of the circular through hole increases. In addition, in actual projects, distribution boards often need to be constructed by cutting first and then assembling. This construction method will inevitably destroy a certain number of through holes. Based on many years of engineering experience, the inventor found that when the diameter of the circular through hole is larger than When 0.03D ₀ , the proportion of the number of through holes destroyed by construction increases, and there is a significant difference between the actual through hole area of the distribution plate and the theoretical through hole area, resulting in unsatisfactory actual distribution effect of the distribution plate. Therefore, all things considered, the diameter D ₃ (unit mm) of the distribution plate through hole of the present invention is preferably (0.01 to 0.03) D ₀ , where D ₀ is the diameter of the distributor (unit mm).

In the present invention, the distribution plate has a large area and a large number of circular through holes. When the circular through holes are arranged staggered at 60 degrees, according to the geometric relationship, the center distance d (unit mm) of the circular through holes of the distribution plate satisfies formula: Among them, φ is the porosity of the distribution plate, that is, the ratio of the sum of the circular through hole areas and the circular area of the distribution plate, and the value is 0.3 to 0.5; D ₃ is the diameter of the circular through hole (unit: mm), and the value is 0.01 ~0.03D ₀ , D ₀ is the diameter of the gas distribution plate; π is the pi ratio, which can be taken as 3.1415926 for calculation.

After research, the inventor found that the porosity of the distribution plate has the following effects on gas distribution: (1) When the porosity of the distribution plate is approximately equal to 0.3, the uniform distribution effect of gas at the distributor outlet is best; (2) When the porosity of the distribution plate is greater than When 0.3, the circulation area of the distribution plate is larger, the throttling effect becomes worse, and the distribution effect of the distribution plate decreases; (3) When the porosity of the distribution plate is less than 0.3, the area near the wall of the distribution plate has a large shielding area, and the mainstream velocity in this area decreases. The gradient changes greatly, and the vortex area occupies a large proportion; at the same time, in the center area of the distribution plate, due to the smaller through hole area of the distribution plate, the real flow velocity of the airflow is larger when passing through the through hole, and the jet effect is obvious. These two phenomena together lead to a decrease in the uniform distribution effect of the distribution plate. At this time, the uniformity of the gas at the distributor outlet decreases as the porosity of the distribution plate decreases. In addition, based on many years of engineering experience, the inventor found that when the porosity of the distribution plate is less than 0.3, the through hole area of the distribution plate is small, the distribution plate has greater gas resistance, greater pressure loss, and significantly increased energy consumption, which is not conducive to downstream catalysis. Chemical reaction process in the layer. Considering that a certain number of through holes will inevitably be damaged during actual construction, resulting in the actual porosity being smaller than the theoretical value, therefore, the porosity φ of the distribution plate in the present invention is preferably 0.3 to 0.5.

In some embodiments of the present invention, the distribution plate assembly further includes a first cylinder, the periphery of the gas distribution plate is connected to the inner wall of the first cylinder, and the internal space of the first cylinder forms a third cylinder. Three gas channels, the third gas channel is connected with the second gas channel. In order to facilitate installation, the shape of the first cylinder in the present invention may be cylindrical, and the gas outlet end of the second gas dispersion cover and the gas inlet end of the first cylinder are sequentially compositely connected through bolt seals, etc., and the connection points Sealing; the gas enters the third gas channel after being decelerated and pre-distributed by the second gas dispersion cover. A support member is installed on the inner wall of the first cylinder. A multi-layer distribution plate is arranged starting from the entrance of the third gas channel. The above-mentioned reasonable distribution plates are arranged between each layer of distribution plate. spacing.

In some embodiments of the present invention, the angle α between the cross section of the second gas dispersion cover and the second gas channel is 30° to 70°. From a theoretical perspective, the angle α of the second gas dispersion cover is Even if the included angle α is not within the above range, the problem of outlet gas distribution uniformity can be solved. For example, many layers (more than 10 layers) of distribution plates can be used to solve the problem, but it is obviously not feasible in engineering. Regarding this angle, there is currently no relevant structural design guidance in the prior art. Through analysis and years of engineering experience, the inventor found that the angle between the wall of the second gas dispersion cover and the cross-section of the second gas channel has a negative impact on the gas. The effects of distribution uniformity are as follows: (1) The included angle is less than 45°, and the degree of diffusion on the inner wall of the dispersion hood is greater along the direction of gas flow. The fluid on the wall of the dispersion hood is prone to boundary layer separation, which in turn generates vortices and reduces the actual circulation of the gas. The cross-sectional area is reduced, the gas diffusion deceleration effect is poor, and the gas uniformity at the distributor outlet is poor; (2) The included angle is greater than 65°, the diffusion degree on the inner wall of the dispersion hood along the gas flow direction is small, the deceleration pre-distribution effect is not obvious, and at the same time the dispersion The height of the cover is significantly increased, which is not conducive to actual installation and processing. Based on the above analysis, in the present invention, it is preferred that the included angle α is 45 to 65°.

Generally, the inlet pipe of the distributor is the top air inlet, and the diameter of the inlet pipe matches the epitaxial equipment, and then the gas is distributed. However, after calculation and analysis and practical engineering experience, the inventor surprisingly found that the gas distribution effect under this air intake method depends heavily on the diameter of the inlet pipe and the uniformity of the inlet flow. When the diameter of the inlet pipe is small or the inlet flow is uniform, When the performance is poor, the gas distribution effect of the distributor is seriously deteriorated. Therefore, the gas distribution effect of this type of distributor is obviously limited by the diameter of the inlet pipe and the uniformity of the inlet flow. However, in actual projects, the diameter and layout of the inlet pipe are limited by many factors such as on-site space and extension equipment, and it is difficult to ensure good uniformity of the actual inlet gas flow. Therefore, the applicability of the top air inlet type distributor in actual projects is limited. Very poor. To this end, the inventor creatively proposed the multi-level distribution idea of "diffusion rectification" - "deceleration pre-distribution" - "throttle main distribution", and set the gradually expanding component in the present invention into a double-layer dispersion cover structure, that is, A first gas dispersion cover is set outside the second gas dispersion cover. The space between the first gas dispersion cover and the second gas dispersion cover forms a first gas channel. The first gas channel and the The second gas channel is connected and arranged; and the inlet pipe of the reaction raw material gas is arranged on the first gas dispersion cover close to the gas outlet of the second gas dispersion cover. Through this side air intake method of the distributor and the first The gas channel expands and rectifies the gas. On the one hand, it can eliminate the influence of the diameter of the inlet pipe and the inlet flow rate distribution on the performance of the distributor, greatly improving the applicability of the distributor. On the other hand, it can further improve the gas distribution at the outlet of the distributor. Uniformity.

In some embodiments of the present invention, the first gas dispersion cover is composed of a head and a cylindrical second cylinder sequentially connected through welding or bolt sealing rings, and the connection is sealed; the head can be universal and conform to the construction in which it is located. It suffices to comply with the permitted specification requirements of the country. This is well known to those skilled in the art. For example, for the ellipsoidal head in the GB/T2519-2010 standard, the top of the head is the top of the first gas dispersion cover. A support member is installed on the inner wall of the second cylinder, and the second gas dispersion cover is connected to the second cylinder through the support member. The cross-sectional diameter of the gas outlet of the second gas dispersion cover is equal to the diameter of the unsealed gas outlet of the second cylinder. The cross-sectional diameter of one end connected to the head (corresponding to the bottom surface of the first gas dispersion cover) and the diameter _D0 of the gas distribution plate are both the same, collectively referred to as the distributor diameter. The bottom surface of the first gas dispersion hood and the gas outlet cross-section of the second gas dispersion hood are located on the same plane, and the cylindrical second cylinder of the first gas dispersion hood is of the same height as the first gas dispersion hood. The gas entering the first gas dispersion hood from the inlet pipe on the side of the distributor flows to the head along the outer wall of the second gas dispersion hood and collects. The gas undergoes first-stage diffusion rectification; the gas in the head flows from the second gas dispersion hood to the head. The gas inlet of the gas dispersion hood flows into the second gas dispersion hood. Due to the gradual expansion of the gas circulation area, the gas is pre-distributed by the second-stage deceleration; then the gas enters the third gas channel and is placed between the multi-layer porous structure gas distribution plate. Under the action, on the one hand, the throttling resistance makes the air flow radially uniform, and on the other hand, due to the throttling effect of the through holes, a gas jet is formed. Each jet gas passing through multiple through holes will gather under the gas distribution plate to create a convergence area. , when the distribution plate spacing h meets the above conditions, it can ensure that the convergence area has enough space to entrain and interfere with each other among the gas jets, and promote the third-level throttling main distribution of gas. After passing through the above three-stage distribution, the gas flows out uniformly from the outlet of the distributor. The schematic diagram of the principle of uniform gas distribution by the gas distributor of the present invention is shown in Figure 4a and Figure 4b.

In embodiments of the present invention, the total height H ₁ (unit mm) of the first gas dispersion hood is preferably (H ₂ +0.25D ₀ ), where H ₂ is the height of the second gas dispersion hood and is also the height of the first gas dispersion hood. The height of the second cylinder of the cover, in mm, and D ₀ is the diameter of the distributor (in mm). If a head of other structures is used, the total height H ₁ of the first gas dispersion cover is the sum of the height of the second cylinder and the height of the head of this structure.

Regarding the height of the second gas dispersion cover, there is currently no relevant literature to study this, and there is no reference basis for the impact of its height on the distribution uniformity of the distributor. To facilitate calculation and construction, the shape of the second gas dispersion cover corresponds to the side of a circular cone. The present invention has found that the height of the second gas dispersion hood has the following effects on the uniformity of gas distribution: (1) When the height of the second gas dispersion hood is greater than 80% of the height of the cone corresponding to the truncated cone, the inlet area of the second gas dispersion hood Smaller, the inlet flow velocity of the second gas dispersion hood is larger, the deceleration pre-distribution effect of the gas in the second gas dispersion hood becomes worse, and the unevenness of the final pre-distribution of the overall gas increases as the height of the second gas dispersion hood increases. In addition A large height of the second gas dispersion hood is also not conducive to actual installation and processing; (2) When the height of the second gas dispersion hood is less than 50% of the height of the cone corresponding to the truncated cone, the inlet area of the second gas dispersion hood is larger, and the gas The deceleration pre-distribution is improved, but the height of the second gas dispersion hood is lower, and the gas flow path in the first gas dispersion hood is shorter, resulting in a worse gas diffusion and rectification effect. The overall gas final pre-distribution unevenness increases with the height of the dispersion hood. In addition, the small height of the second gas dispersion cover is not conducive to the arrangement of auxiliary installation devices such as lifting lugs. Through the above analysis, in the present invention, it is preferred that the height of the second gas dispersion cover is 0.5 to 0.8 times the height of its corresponding cone, that is, the height H ₂ (unit mm) of the second gas dispersion cover satisfies: Wherein, B _h is the height coefficient of the second gas dispersion hood, which ranges from 0.5 to 0.8, and α is the angle between the second gas dispersion hood and the cross section of the second gas channel, which ranges from 30 to 70°, preferably 45~65°, D ₀ is the diameter of the distributor (unit: mm).

Generally, there is only one inlet pipe of the gas distributor, and it is set at the top of the distributor. In the embodiment of the present invention, it is preferred that the distributor has at least two inlet pipes, which are symmetrically arranged on the outer wall of the first gas dispersion cover. The inlet pipe is connected to the first gas dispersion cover through welding or bolt sealing rings, the connection is sealed, and the gas enters the first gas channel through the inlet pipe. Based on many years of engineering experience, the inventor prefers that the structural parameters of the inlet pipeline are as follows:

The inlet pipe cross-section is preferably a circular cross-section. The diameter and length of the inlet pipe are mainly determined based on the diameter of the distributor. The main constraints are: (1) The inlet pipe is connected to the first gas dispersion cover, and its diameter should not be too large to avoid causing the first gas dispersion cover. The larger openings on the side of the gas dispersion cover generally require the diameter of the inlet pipe to be less than 0.2D ₀ , and D ₀ is the diameter of the distributor; (2) In order to meet the needs of large-capacity production and ensure smooth air intake in the inlet pipe, the diameter of the inlet pipe should not be too small. , it is generally required that the diameter of the inlet pipeline is greater than 0.1D ₀ , and D ₀ is the diameter of the distributor; (3) In order to ensure that the raw gas is distributed as uniformly as possible in the inlet pipeline, the length of the inlet pipeline should not be too short, and it is generally required that the length of the inlet pipeline is greater than 1.0D _inlet ; (4) In order to facilitate on-site installation, the length of the inlet pipe should not be too long. Generally, the length of the inlet pipe is required to be less than 2.0D _inlet . In addition, when installing the inlet pipe, it should be installed as low as possible on the outer wall of the first gas dispersion hood. Preferably, the distance h _inlet between the inlet pipe and the bottom surface of the first gas dispersion hood is 0 to 900 mm.

The distribution performance of the gas distributor provided by the embodiment of the present invention is basically not affected by the cross-sectional shape of the inlet pipe, the air inlet velocity of the pipe, etc. If the cross section of the inlet pipe is not suitable or cannot be circular, common cross-sectional shapes in engineering such as ellipse, rectangle or square can also be used. At this time, the equivalent diameter D _e is used to calculate, D _e is 0.1 to 0.2D ₀ , and D ₀ is the distribution device diameter. If it is not appropriate or impossible to use two channels for the inlet pipeline, a single or multiple channels can also be used. The sum of the cross-sectional areas of all inlet pipelines is preferably equal to the sum of the cross-sectional areas of the two inlet pipelines, and they should be arranged as symmetrically as possible on the second gas dispersion cover. on the outer wall.

The gas distributor provided by the embodiment of the present invention has a simple structure and can be embedded into an existing reactor as a whole, or can be split into multiple components and installed in the existing reactor respectively. There is no need to modify the structure of the existing reactor, and it is easy to assemble. Low cost.

The reactor in the present invention is used for gas-solid phase reactions, including but not limited to catalytic oxidation, catalytic hydrogenation, catalytic hydrocracking, catalytic dehydration, hydroamination, catalytic dehydrogenation, catalytic isomerization, and catalytic ammonia oxidation. etc., specifically, including but not limited to the direct oxidation of ethylene to prepare ethylene oxide, the ammonia oxidation of propylene to prepare acrylonitrile, the oxidation of propylene to prepare acrolein and acrylic acid, the dehydrogenation of 1,4-butanediol to prepare γ-butyrolactone, Hydrogenation of dimethyl oxalate to ethylene glycol, oxidation of ethanol to acetaldehyde, gas phase hydrogenation of maleic anhydride to γ-butyrolactone, amination and dehydration of acetic acid to acetonitrile, ammoxidation of methylpyridine to cyanopyridine, and ammoxidation of toluene. Hydrogenation of benzonitrile and acetone to produce isopropyl alcohol, hydroamination of acetone to produce isopropylamine, hydrogenation of pyridine to produce piperidine, dehydrogenation of cyclohexanol to produce cyclohexanone, dehydrogenation of 2-butanol to produce methyl ethyl ketone, gas phase addition of furfural Hydrogen to produce furfuryl alcohol, butyraldehyde or octylaldehyde and gas phase hydrogenation to produce butanol or butanol.

The present invention is the first to design a distributor structure in which the gradually expanding component and the distribution plate component of the double-layer dispersion cover are sequentially and compositely connected. A diffusion rectification area and a deceleration pre-distribution area are respectively constructed on the outside and inside of the second gas dispersion cover. , the gas after the first-stage expansion and rectification flows into the deceleration pre-distribution area, realizing the second-stage deceleration pre-distribution of the gas, and then carries out the third-stage throttling main distribution through the third gas channel of the built-in multi-layer distribution plate. After extensive research, the inventor found that the gas distributor of the present invention can achieve uniform gas dispersion in the range of the average flow velocity of the distributor outlet cross-section of 0.1 to 2.5 m/s, and the gas distribution effect is basically not affected by the average flow velocity of the outlet and is uniform. The distribution stability is good.

The gas distributor provided by the present invention will be further described below with reference to specific embodiments.

Example 1: Multi-stage pressure diffusion deceleration gas distributor for 100,000 tons/year ethanol oxidation to acetaldehyde reactor

In order to further understand the present invention, the gas distributor of the present invention will be described in detail below with reference to an example of a 100,000 tons/year ethanol oxidation to acetaldehyde production device. The 100,000-ton acetaldehyde production device uses air and ethanol mixed before entering the reactor. The raw gas volume flow Q is 30268m ³ /h, the feed temperature is 120°C, and the feed pressure is 30KPa. An adiabatic reactor is used, and the reactor bed is a flat electrolytic silver catalyst.

As shown in Figures 1 and 2, the gas distributor provided in this implementation includes a gradually expanding component and a distribution plate component that are sequentially arranged along the direction of gas flow, wherein:

The gradually expanding assembly includes a first gas dispersion cover 2 and a second gas dispersion cover 3 located inside the first gas dispersion cover 2. The second gas dispersion cover 3 has a gas inlet 31 and a gas outlet 32. A second gas channel is formed between the inlet 31 and the gas outlet 32, and the cross-sectional area of the second gas channel gradually increases along the gas flow direction; the first gas dispersion cover 2 and the second gas dispersion cover The space between the covers 3 forms a first gas channel, the first gas channel is connected with the second gas channel, and the first gas dispersion cover 2 is close to the gas outlet of the second gas dispersion cover 3 There are inlet pipelines 1 at 32 locations.

In this embodiment, the first gas dispersion cover 2 is composed of a head 21 and a cylindrical second cylinder 22 through a welding sequence. The connection is sealed. A supporting member is installed on the inner wall of the second cylinder 22. The second gas dispersion cover 3 is connected to the second cylinder 22 of the first gas dispersion cover 2 through the supporting member. The second gas dispersion cover 3 is of the same height as the second cylinder 22 of the first gas dispersion cover 2. The dispersion hood 3 corresponds to the side of a truncated cone, the bottom surface of the truncated cone (i.e., the gas outlet cross section of the second gas dispersion hood) and the end of the second cylinder of the first gas dispersion hood that is not connected to the head (i.e., the first gas dispersion hood). The bottom surface of the dispersion hood) is located on the same plane; two circular inlet pipes 1 are symmetrically arranged on the outer wall of the first gas dispersion hood 2, and the inlet pipe 1 is connected to the first gas dispersion hood 2 through a bolt sealing ring. , the connection is sealed.

The distribution plate assembly includes a first cylinder 5 and at least two parallel and spaced apart gas distribution plates 4. The first cylinder 5 is cylindrical and is sealed with the second cylinder 22 of the first gas dispersion cover 2 by welding. connection, each gas distribution plate 4 is a circular thin plate with a number of through holes provided on it, as shown in Figure 3, and the periphery of each gas distribution plate 4 is connected to the first cylinder 5 are tightly connected, the internal space of the first cylinder 5 forms a third gas channel, the third gas channel is connected with the second gas channel, and the gas outlet of the third gas channel is the distributor outlet 6 .

In this embodiment, based on given process requirements, the structural parameters of the distributor can be designed according to the formula and/or parameter range given by the present invention. In order to explain in detail that the formulas and/or parameter ranges given in the present invention are optimal, the influence of each distributor structural parameter value on the distribution effect of the distributor is analyzed in detail in this embodiment. In the process of analyzing the influence of a certain structural parameter value on the distribution effect of the distributor, the structural parameter takes different values, while other structural parameters remain unchanged, and the changing trend of the gas unevenness at the distributor outlet as the structural parameter changes is analyzed. The structural parameters of the gas distributor are designed as follows:

①Diameter of distributor

For the multi-stage diffusion deceleration gas distributor in this embodiment, the result chart of the gas unevenness at the distributor outlet as a function of the outlet average flow rate is obtained through calculation, as shown in Figure 5. As can be seen from Figure 5, in the average outlet flow velocity range of 0.1 to 7m/s, the outlet gas unevenness of the distributor described in this embodiment is 0.36, which shows that the gas distribution after flowing through the distributor of this embodiment Uniform and can well meet engineering needs. Moreover, as the average flow rate of the outlet gas increases, the unevenness of the gas at the outlet of the distributor remains unchanged, indicating that the uniform distribution of the distributor in this embodiment has good stability and has little dependence on the flow rate. In practical engineering applications, there are Wide scope of application and obvious applicability advantages.

Taking the average velocity of the gas at the distributor outlet as 0.75m/s, according to the calculation formula of the gas distributor diameter D ₀ provided by the present invention:

After rounding, the diameter of the distributor is DN3800mm.

②Structure of the second gas dispersion cover

For the multi-stage diffusion deceleration gas distributor described in this embodiment, the distribution diagram of the gas unevenness at the distributor outlet as a function of the angle α of the second gas dispersion cover is obtained through calculation. It can be seen from Figure 6 that the greater the included angle, the higher the wall height of the second gas dispersion cover, the longer the gas diffusion rectification path, and the lower the outlet gas unevenness. This is consistent with the inventor's many years of engineering experience. ; (2) The included angle is less than 45°, the gas non-uniformity at the distributor outlet is greater than 0.4, and the gas distribution uniformity is poor. This is because the gas diffuses to a greater extent along the flow direction on the inner wall of the second gas dispersion cover, and the second gas The fluid at the wall of the dispersion cover is more likely to have boundary layer separation, which in turn generates vortices, reducing the actual flow cross-sectional area of the gas, and the gas diffusion deceleration effect is poor; (3) The angle is greater than 65°, and the second gas is dispersed along the flow direction. The degree of diffusion on the inner wall of the hood is small, and the deceleration pre-distribution effect is not obvious. At the same time, the height of the second gas dispersion hood increases significantly when the included angle is large, which is not conducive to actual installation and processing. Through the above analysis, the present invention determines that the included angle α is preferably 45 to 65°, and is 50° in this embodiment.

For the multi-stage diffusion deceleration gas distributor described in this embodiment, the distribution diagram of the gas unevenness at the distributor outlet as shown in Figure 7 changes with the ratio of the height of the second gas dispersion cover to the corresponding cone height. . It can be seen from Figure 7: (1) When the height of the second gas dispersion cover is greater than 80% of the height of its corresponding cone, the unevenness of the distributor outlet is greater than 0.4, and the gas distributor effect is poor; (2) When the height of the second gas dispersion cover is equal to 50%-55% of the height of its corresponding cone, the unevenness of the distributor outlet is basically at the lowest value of 0.27, and the gas distributor effect is better. Considering that auxiliary devices such as lifting lugs may be installed on the outer wall of the distributor, the height of the second gas dispersion hood (corresponding to the height of the second cylinder of the first gas dispersion hood) generally should not be too small. Through the above analysis, the present invention determines that the height H ₂ of the second gas dispersion cover is 0.5 to 0.8 times the height of the corresponding cone. Specifically, it can be calculated using the following formula: Among them, B _h is the height coefficient of the second gas dispersion hood, which takes 0.5 to 0.8, α is the angle between the cross section of the second gas dispersion hood and the second gas channel, and D ₀ is the diameter of the distributor (unit mm) .

In this embodiment, the distributor diameter D ₀ is 3800 mm, the acute angle α between the second gas dispersion cover and the cross section of the second gas channel is 50°, and the height coefficient B _h of the second gas dispersion cover is 0.7, the height _H2 of the second gas dispersion cover is calculated as:

③Structure of the first gas dispersion cover

For the multi-stage diffusion deceleration gas distributor described in this embodiment, the head structure adopts the ellipsoidal head in the Chinese GB/T2519-2010 standard or other heads of the same type that meet the standard. In this embodiment, an EHA type ellipsoidal head is used. The main parameters are: long axis 3800mm, short axis 1900mm; therefore, the height H ₁ of the first gas dispersion cover is:

H ₁ =(H ₂ +0.25D ₀ )=1585+0.25×3800=2535mm.

④Distribution board structure

For the multi-stage expansion deceleration gas distributor described in this embodiment, in order to facilitate processing, the thickness _H3 of the distribution plate is taken to be 5mm, and the circular through holes on the distribution plate are arranged staggered at 60 degrees, as shown in Figure 3. The following determines the through hole diameter of the distribution plate and the hole center distance between two adjacent through holes.

After calculation, the variation of gas unevenness at the distributor outlet with the diameter of the circular through hole of the distribution plate is obtained as shown in Figure 8. It can be seen from Figure 8 that (1) when the diameter of the circular through hole is less than 35mm (about 0.01D ₀ ), the diameter of the circular through hole is small, and the gas flows through the through hole to easily form a strong jet flow, and the gas distribution effect is The gas unevenness at the distributor outlet increases as the diameter of the circular through hole decreases; (2) When the diameter of the circular through hole is 40mm ~ 150mm (about 0.001D ₀ ~ 0.04D ₀ ), the circular through hole The hole diameter is relatively reasonable, and the gas will produce a suitable throttling effect through the circular through hole. The gas will gather under the distribution plate to create a reasonable convergence area. The gas jets in the convergence area will entrain and interfere with each other. The gas distribution effect is better, and the gas at the outlet of the distributor The non-uniformity remains at a stable low value in this interval; (3) When the diameter of the circular through hole is greater than 150mm (about 0.04D ₀ ), the diameter of the circular through hole is larger, and the gas cannot form an effective gas after flowing through the through hole. Due to the throttling effect, the gas distribution effect is poor, and the gas unevenness at the partitioner outlet increases as the diameter of the circular through hole increases. In addition, in actual projects, distribution boards often need to be constructed by cutting first and then assembling. This construction method will inevitably destroy a certain number of through holes. Based on many years of engineering experience, the inventor found that when the diameter of the circular through hole is greater than 110mm (about 0.03D ₀ ), the proportion of the number of through holes destroyed by construction increases, and the actual through hole area of the distribution plate and the theoretical through hole area show a difference. The obvious difference results in the actual distribution effect of the distribution plate being significantly lower than the theoretical calculation. Therefore, the diameter D ₃ of the circular through hole of the distribution plate in the present invention is preferably (35 mm to 110 mm), that is, (0.01 to 0.03) D ₀ , where D ₀ is the diameter of the distributor. In this embodiment, the circular through hole The diameter _D3 is taken as 40mm.

According to the geometric relationship, there is a certain mathematical relationship between the hole center distance of the circular through hole of the distribution plate, the diameter of the circular through hole of the distribution plate and the porosity of the distribution plate. For the multi-stage diffusion deceleration gas distributor described in this embodiment, the graph of the change of gas unevenness at the distributor outlet with the porosity of the distribution plate as shown in Figure 9 is obtained through calculation. It can be seen from Figure 9 that when the porosity is 0.3, the gas unevenness at the distributor outlet is minimal. This is because when the porosity of the distribution plate is greater than 0.3, the distribution plate flow area is larger and the gas throttling effect becomes worse. , the distribution effect of the distribution plate decreases; when the porosity of the distribution plate is less than 0.3, the area near the wall of the distribution plate has a large shielding area, the mainstream velocity gradient in this area changes greatly, and the vortex area occupies a large area, while the central area of the distribution plate is due to the distribution plate. The area of the through hole is small, the actual flow speed of the air flow through the through hole is larger, and the jet effect is obvious. These two phenomena jointly cause the distribution effect of the distribution plate to decrease, and the gas unevenness at the distributor outlet increases as the porosity of the distribution plate decreases. In addition, based on many years of engineering experience, the inventor found that when the porosity of the distribution plate is less than 0.3, the through hole area of the distribution plate is small, the distribution plate has greater gas resistance, greater pressure loss, and significantly increased energy consumption, which is not conducive to downstream catalysis. Chemical reaction process in the layer. According to the inventor's many years of engineering experience, during the actual construction and installation process of the distribution board, a certain number of through holes will inevitably be damaged, resulting in the actual porosity of the distribution board being smaller than the theoretical value. Through theoretical analysis and practical engineering experience, it is determined that the porosity φ of the distribution plate of the present invention is preferably 0.3 to 0.5. In this embodiment, it is 0.4. Correspondingly, the hole center distance between two adjacent circular through holes adopts the following formula calculate:

⑤Structure of distribution board assembly

A multi-layer distribution plate is arranged starting from the entrance of the third gas channel. The spacing between distribution plates and the number of distribution plates determine the length of the third gas channel. These three structural parameters are determined below.

Determination of the distribution plate spacing: When the distribution plate spacing is small and the gas flow rate through the distribution plate through holes is high, the gas will directly pass through the lower distribution plate and cannot form a convergence area under the distribution plate. At this time, the gas flows through the two layers The distribution plate is similar to the flow through a single-layer distribution plate, that is, the second distribution plate does not work and a "short circuit" occurs. A short circuit of the distribution plate will significantly reduce the production capacity of the reactor. Increasing the spacing between the distribution plates can avoid the "short circuit" phenomenon of the distribution plates. For the multi-stage diffusion deceleration gas distributor described in this embodiment, the variation diagram of the gas unevenness at the distributor outlet with the spacing between the distribution plates is obtained through calculation, as shown in Figure 10. As can be seen from Figure 10, when the distribution plate spacing is 100mm, the gas unevenness at the distributor outlet is as high as 1.3, which is caused by the "short circuit" phenomenon of the distribution plate. Subsequently, as the spacing between distribution plates increases, the gas unevenness at the distributor outlet decreases. When the plate spacing increases to 400mm, the gas unevenness at the distributor outlet will reach the lowest value. There is no backflow under the last layer of distribution plate, and the maximum flow rate of gas at the distributor outlet is significantly reduced. It shows that increasing the spacing between distribution boards can solve the "short circuit" phenomenon of distribution boards, which is consistent with the inventor's many years of engineering experience. Subsequently, as the spacing between distribution plates increases, the gas unevenness at the distributor outlet increases slightly. When the spacing between distribution plates is in the range of 350mm to 550mm, the gas unevenness at the distributor outlet is less than 0.4, which is beneficial to the chemical reaction process. Through the above analysis, the present invention proposes a calculation formula for the distribution plate spacing Δh: The value after rounding is 400mm. In this embodiment, the gas jet convergence coefficient _Ch is 0.044 in the preferred range of 0.02 to 0.1. At the same time, considering the actual construction and installation, the absolute height value of the distribution plate spacing is greater than 100mm.

Determination of the number of distribution plates: For the multi-stage diffusion deceleration gas distributor described in this embodiment, the distribution diagram of the gas unevenness at the distributor outlet as a function of the number of distribution plates is obtained through calculation as shown in Figure 11. It can be seen from Figure 11 that when the spacing between distribution plates is 400mm, the more distribution plates, the better the gas distribution effect. However, when the number of porous distribution plates is greater than 4, the increase in the number of distribution plates will have an even effect on the distribution of air flow velocity. The improvement is limited, which is consistent with the inventor's many years of engineering experience. In addition, in actual projects, when the number of porous distribution plates is greater than 6, the length of the third gas channel will be longer, which is not conducive to actual production line construction. Considering the actual construction and production of the chemical industry, the number N of distribution plates in the present invention is preferably 3 to 6 layers. In this embodiment, the number N of distribution plates is 4.

Therefore, the third gas channel length H ₄ in this embodiment is: H ₄ =N×Δh=4×400=1600mm.

⑥Inlet channel structure

Generally, the inlet pipe of the distributor is top-intake. The gas distribution effect of this type of distributor is limited by the diameter of the inlet pipe and the uniformity of the inlet gas flow. The inventor creatively developed the side air intake method of the distributor. Based on this idea, in this embodiment, the inlet pipe section is designed to be a circular section, and the inlet pipe is preferably two channels. After calculation, the variation of gas unevenness at the distributor outlet with the diameter of the inlet pipe is obtained as shown in Figure 12. It can be seen from Figure 12 that as the diameter of the inlet pipe changes in the range of 280 to 600 mm, the gas unevenness at the distributor outlet in this embodiment is about 0.4, with very small fluctuations. This shows that the present invention uses side air intake and double The layered dispersion hood diffuses and rectifies the inlet gas, which can largely eliminate the influence of the diameter of the inlet pipe on the performance of the distributor and greatly improves the applicability of the distributor.

In this embodiment, the inlet pipe diameter D _inlet is within the preferred range of (0.1 to 0.2) D ₀ , that is, 380 mm to 760 mm, and is taken to be 565 mm; the inlet pipe length L _inlet is within the preferred range of (1.0 to 2.0) D _inlet , that is, 565 mm to 1130 mm. Within the range, it is taken as 900mm; the height of the inlet pipe (that is, the distance between the inlet pipe and the bottom surface of the first gas dispersion cover) h _inlet is taken as 435mm in the preferred range of 0 ~ 900mm.

⑦Gas distribution effect at the distributor outlet

In order to illustrate the gas distribution effect of the sparger in this embodiment, the sparger outlet velocity cloud diagram shown in Figure 13 was calculated. It can be seen from Figure 13 that the outlet velocity ranges from 0 to 0.98m/s, and the velocities are all greater than 0 and less than 2.0m/s. This shows that there is no backflow at the distributor outlet of Example 1, and the flow rate into the catalyst reaction layer is suitable for Chemical reaction requirements. The flow velocity in this cloud diagram is mainly yellow, and the flow velocity range in this interval is about 0.75m/s, which shows that the flow velocity at the distributor outlet of Example 1 is mainly distributed around the average value of 0.75m/s, and the distribution uniformity is good. The gas unevenness at the distributor outlet of Example 1 is only 0.142, which is less than the recommended value of 0.4, which further illustrates that the gas distribution effect of the distributor of Example 1 is good.

Example 2: Multi-stage pressure expansion deceleration gas distributor for 50,000 tons/year ethanol oxidation to acetaldehyde reactor

In order to further understand the present invention, an example of a 50,000 tons/year acetaldehyde production device is given below. 50,000 tons of ethanol air catalytic oxidation to acetaldehyde reactor, air and ethanol are mixed into the reactor, the ethanol feed amount is 13100kg/h, the air feed amount is 7900kg/h, the feed temperature is 135°C, after mixing The volume Q is 15600m ³ /h (working condition). An adiabatic reactor is used, and the reactor bed is a flat electrolytic silver catalyst.

The distributor structure of Embodiment 2 is the same as that of Embodiment 1 except for the following structural parameters.

①Diameter of distributor

Taking the average velocity of the distributor outlet as 0.77m/s, the gas distributor diameter D ₀ is calculated to be 2676mm, which is DN2700mm after rounding.

②Structure of the second gas dispersion cover

The included angle α of the second gas dispersion hood is 60 degrees, the height coefficient B _h of the second gas dispersion hood is taken as 0.7, and the calculated height H ₂ of the second gas dispersion hood is 1637 mm.

③Structure of the first gas dispersion cover

The height _H1 of the first gas dispersion cover is 2312mm.

④Distribution board structure

The thickness _H3 of the distribution plate is 5mm, and the diameter _D3 of the circular through hole is 40mm.

The porosity φ of the distribution plate is taken as 0.35, and the hole center distance is calculated as 65mm.

⑤Structure of distribution board assembly

The gas jet convergence coefficient _Ch is 0.053, the distribution plate spacing Δh is 350mm, the number of distribution plates N is 3, and the third gas channel length H ₄ is 1050mm.

⑥Inlet channel structure

The diameter D _inlet of the inlet pipe is 300mm, the length L _inlet is 400mm, and the height h _inlet is 400mm.

⑦Exit gas distribution effect

In order to illustrate the gas distribution effect of the sparger in Example 2, the sparger outlet velocity cloud diagram shown in Figure 14 was calculated. It can be seen from Figure 14 that the outlet velocity ranges from 0 to 1.47m/s, and the velocities are all greater than 0 and less than 2.0m/s. This shows that there is no backflow at the distributor outlet of Example 2, and the flow rate into the catalyst reaction layer is suitable for the chemical industry. Respond to needs. The flow velocity in this cloud diagram is mainly green and light yellow, and the flow velocity range in this interval is about 0.5-1.0m/s, which shows that the flow velocity at the outlet of the distributor in Example 2 is mainly distributed around the average value of 0.77m/s, and the distribution is uniform. Good sex. The gas unevenness at the distributor outlet of Example 2 is only 0.208, which is less than the recommended value of 0.4, which further illustrates that the gas distribution effect of the distributor of Example 2 is good.

Example 3: 20,000 tons/year ammonia acetate condensation and dehydration to produce acetonitrile reactor with multi-stage pressure diffusion deceleration gas distributor

In order to further understand the present invention, an example of a 20,000 tons/year acetonitrile production device is given below. 20,000 tons/year acetic acid and ammonia are condensed and dehydrated to prepare an acetonitrile reactor. The catalyst is loaded in the tubes and an isothermal reactor design is adopted. The feed amount of acetic acid is 13600kg/h, the feed amount of ammonia is 8230kg/h, the temperature before entering the reactor distributor is 390°C, the flow rate Q of the volume entering the distributor after mixing is 12800m ³ /h (working condition), enter The average gas velocity of the tube plate on the reactor (ie, the entrance to the catalyst reaction layer) is 1.2m/s.

The distributor structure of Embodiment 3 is the same as that of Embodiment 1 except for the following structural parameters.

①Diameter of distributor

Take the gas distributor diameter D ₀ as DN2000mm.

②Structure of the second gas dispersion cover

The included angle α of the second gas dispersion hood is 55 degrees, the height coefficient B _h of the second gas dispersion hood is taken as 0.7, and the calculated height H ₂ of the second gas dispersion hood is 1000 mm.

③Structure of the first gas dispersion cover

The height _H1 of the first gas dispersion cover is 1500mm.

④Distribution board structure

The thickness _H3 of the distribution plate is 5mm, the diameter _D3 of the circular through hole is 30mm, the porosity φ of the distribution plate is 0.4, and the hole center distance is calculated as 45mm.

⑤Structure of distribution board assembly

The gas jet convergence coefficient _Ch is 0.067, the distribution plate spacing Δh is 450mm, the number of distribution plates N is 3, and the third gas channel length H ₄ is 1350mm.

⑥Inlet channel structure

The diameter D _inlet of the inlet pipe is 300mm, the length L _inlet is 400mm, and the height h _inlet is 400mm.

⑦Exit gas distribution effect

In order to illustrate the gas distribution effect of the sparger in Embodiment 3, the sparger outlet velocity cloud diagram shown in Figure 15 was calculated. It can be seen from Figure 15 that the outlet velocity ranges from 0 to 2.0 m/s, and the velocities are all greater than 0. This shows that there is no backflow at the distributor outlet of Example 3, and the flow rate into the catalyst reaction layer is suitable for chemical reaction needs. The flow velocity in this cloud diagram is mainly light yellow, and the flow velocity range in this interval is about 0.7-1.5m/s. This shows that the flow velocity at the outlet of the distributor in Example 3 is mainly distributed around the average value of 1.2m/s, and the distribution uniformity is good. . The gas non-uniformity at the outlet of the distributor in Example 3 is 0.39, which is less than the recommended value of 0.4, which further illustrates that the gas distribution effect of the distributor in Example 3 is good.

Example 4: 50,000 tons/year butanediol (BDO) hydrodehydrogenation to produce γ-butyrolactone (GBL) reactor using a multi-stage diffusion deceleration gas distributor

One set of 50,000 tons/year 1,4-butanediol (BDO) hydrodehydrogenation to γ-butyrolactone (GBL) reactor. The dehydrogenation catalyst is loaded in the tubes and adopts an isothermal reactor design. The BDO feed rate is 6688kg/h, the hydrogen feed rate is 2080kg/h, the temperature before entering the reactor distributor is 240°C, the volume flow Q after mixing entering the distributor is 26700m ³ /h (working condition), entering the reaction The average gas velocity of the tube plate on the device (i.e., the entrance of the catalyst reaction layer) is 0.35m/s.

The distributor structure of Embodiment 4 is the same as that of Embodiment 1 except for the following structural parameters.

①Diameter of distributor

Take the gas distributor diameter D ₀ as DN5200mm.

②Structure of the second gas dispersion cover

The included angle α of the second gas dispersion hood is 50 degrees, the height coefficient B _h of the second gas dispersion hood is taken as 0.7, and the calculated height H ₂ of the second gas dispersion hood is 2170 mm.

③Structure of the first gas dispersion cover

The height _H1 of the first gas dispersion cover is 3470mm.

④Distribution board structure

The thickness _H3 of the distribution plate is 5mm, the diameter _D3 of the circular through hole is 80mm, the porosity φ of the distribution plate is 0.35, and the hole center distance is calculated as 130mm.

⑤Structure of distribution board assembly

The gas jet convergence coefficient C _h is 0.09, the distribution plate spacing Δh is 300 mm, the distribution plate number N is 4, and the third gas channel length H ₄ is 1200 mm.

⑥Inlet channel structure

The diameter D _inlet of the inlet pipe is 800mm, the length L _inlet is 1200mm, and the height h _inlet is 650mm.

⑦Exit gas distribution effect

In order to illustrate the gas distribution effect of the sparger in Embodiment 4, the sparger outlet velocity cloud diagram shown in Figure 16 was calculated. It can be seen from Figure 16 that the outlet velocity ranges from 0 to 0.47m/s, and the velocities are all greater than 0 and less than 2.0m/s. This shows that there is no backflow at the distributor outlet of Example 4, and the flow rate into the catalyst reaction layer is suitable for the chemical industry. Respond to needs. The flow velocity in this cloud diagram is mainly light yellow, and the flow velocity range in this interval is about 0.35m/s. This shows that the flow velocity at the outlet of the distributor in Example 4 is mainly distributed around the average value of 0.35m/s, and the distribution uniformity is good. The gas unevenness at the distributor outlet of Example 4 is only 0.166, which is less than the recommended value of 0.4, which further illustrates that the gas distribution effect of the distributor of Example 4 is good.

Comparative Example 1: 50,000 tons/year ethanol oxidation to acetaldehyde reactor (without distributor installed)

The existing industrial equipment is 50,000 tons/year, and the process parameters are consistent with Example 2. The difference is that this comparative example uses a single inlet channel with a diameter of 424mm, vertical air intake from the top of the distributor head, and no dispersion cover and its distribution board below. Calculate the working conditions and obtain the distribution effect diagram entering the catalyst bed, as shown in Figure 17a and Figure 17b. The area not shown in Figure 17b is the area where the velocity value is less than 0. The gas flow in the area where the velocity value is less than 0 is consistent with The direction of the main flow is opposite, which is the return flow area. As can be seen from Figure 17a, the velocity range fluctuates from -1.34 to 28.64m/s. The local flow velocity flowing into the catalyst reaction layer is very large, and there is a large area of backflow, which is not conducive to chemical reactions. Through calculation, it was found that the gas distribution was extremely uneven, and the unevenness value reached 3.65, which was 17.5 times that of Example 2, which was not conducive to chemical reactions.

The silver catalyst in the existing industrial system can only be used for 2 to 3 months before the ethanol conversion rate drops significantly, and there is a very obvious carbon deposition phenomenon. In a typical cycle, the output of 1 ton of ethanol in the early, middle and final stages The ethanol consumed per unit of aldehyde is shown in Table 1. Through comparison, it was found that the ethanol unit consumption of the existing reactor without any distributor is 18.3kg/ton of acetaldehyde higher than that of Example 2 (calculated based on the entire cycle production capacity), and the life span from the initial stage to the end will be shortened by 1612 hours.

Table 1 Reaction results applied in Example 2 and Comparative Example 1

Note: Ethanol content is 95vol%.

Comparative Example 2: 50,000 tons/year ethanol oxidation to acetaldehyde reactor (sparger with only distribution plate and vertical air intake at the top of the distributor)

Comparative Example 2 is a multi-layer distribution plate added to the reactor described in Comparative Example 1. The structure of the distribution plate is the same as that of Example 2, but a dispersion cover is not installed. The structure of this distributor is similar to Chinese patent CN105102104B, which is equivalent to the application of this patent idea in the present invention.

Based on the same feeding conditions of Example 2, the gas distribution effect at the distributor outlet of Comparative Example 2 was calculated. The results are shown in Figure 18a and Figure 18b. The area not shown in Figure 18b is the reflux area, as can be seen from Figure 18a , the velocity range fluctuates from -0.34 to 2.27m/s, there is backflow in a certain area, and the gas unevenness is 0.6, which is about three times that of Example 2. By analogy from this calculation result, when the distributor disclosed in patent CN105102104B is applied to the present invention, the gas distribution effect is poor. This is mainly because this type of distributor does not have a dispersion cover. When the diameter of the inlet pipe is small, the gas flow rate entering the central area of the reactor is very high, resulting in poor uniform distribution of the distribution plate.

Comparative Example 3: Distributor for 50,000 tons/year ethanol oxidation to acetaldehyde reactor

As shown in Figure 19, the gas reactor provided in this comparative example has the same structure as Example 2 except for the location and number of inlet pipes. In this comparative example, an inlet pipe with a diameter of 424 mm is connected to the top of the head of the first gas dispersion hood. The inlet pipe has the same inlet area as the two inlet pipes with a diameter of 300 mm in Example 2. The gas flows through the inlet pipe. Directly into the second gas dispersion hood.

Based on the same feeding conditions of Example 2, the gas distribution effect at the distributor outlet of this comparative example was calculated, and the results are shown in Figure 20. As can be seen from Figure 20, the velocity range fluctuates from 0 to 1.80m/s, and the maximum velocity is less than 2m/s. The gas flow rate flowing into the catalyst reaction layer is conducive to chemical reactions, and there is no backflow area. The gas unevenness is measured as 0.36 , less than the recommended value of 0.4.

In contrast, in Example 2, the maximum gas velocity at the distributor outlet is only 1.47m/s, and the gas unevenness at the distributor outlet is only 0.208. Compared with Comparative Example 3, the maximum velocity and unevenness at the distributor outlet in Example 2 are It is further reduced by 18% and 42%, which shows that the multi-stage diffusion deceleration gas distributor of the present invention adopts symmetrical double-side inlet pipes, which can fully utilize the area between the double-layer dispersion hoods for diffusion rectification, not only The gas distribution effect can be further improved, and the influence of the diameter of the inlet pipe on the distribution effect can be significantly reduced, which is beneficial to improving the applicability of the gas distributor.

Comparative Example 4: 50,000 tons/year ethanol oxidation to acetaldehyde reactor (sparger with large distribution plate spacing)

The layout of the distribution plates has a great influence on the gas distribution effect of the distributor. Only when the distance between the distribution plates is within a reasonable range, the air flow distribution can achieve a relatively uniform distribution state. In order to illustrate this phenomenon, Comparative Example 4 is based on Example 2, and the plate spacing is larger than the plate spacing formula of the present invention. The calculated maximum value. Calculated according to the formula given by the present invention, the maximum plate spacing of Example 2 is 470mm, so the plate spacing of Comparative Example 4 is 700mm.

Based on the same feeding conditions of Example 2, the gas distribution effect at the distributor outlet of Comparative Example 4 was calculated. The results are shown in Figure 21a and Figure 21b. The area not shown in Figure 21b is the reflux area, as can be seen from Figure 21a , the velocity range fluctuates from -0.34 to 3.96m/s, there is backflow in a certain area, and the gas unevenness is 0.72, which is approximately 3.6 times that of Example 2. This shows that when the spacing between distribution plates is large, the gas uniformity at the distributor outlet is poor, which is not conducive to actual engineering production. This is because when the distance between the distribution plates is large, the space under the distribution plates is larger, and the gas flow process is less disturbed. The mutual entrainment and interference movement between the gases are weaker than the mainstream movement, and the gas is mainly flowed by the mainstream. , resulting in reduced gas uniformity distribution. At the same time, when the distance between distribution boards is large, the length of the main distribution channel will be long, which is not conducive to actual production line construction.

Comparative Example 5: 50,000 tons/year ethanol oxidation to acetaldehyde reactor (distributor with small spacing between distribution plates)

If the spacing between the distribution plates is too small, it will cause the distribution plate to "short circuit" and greatly reduce the distribution effect of the distributor. In order to illustrate this phenomenon, Comparative Example 5 is based on Example 2, with the distribution plate spacing reduced to 100 mm.

Based on the same feeding conditions of Example 2, the gas distribution effect at the distributor outlet of Comparative Example 5 was calculated, and the results are shown in Figures 22a and 22b. It can be seen from Figure 22a that when the distribution plate spacing is 100mm, the maximum flow velocity value at the distributor outlet is as high as 2.52m/s, which is significantly larger than the average flow velocity of 0.77m/s; as can be seen from Figure 22b, when the velocity range is (0~2.52) m/s, a large blank area appears in the outlet cloud map, indicating that there is a large backflow area at the outlet, and the gas non-uniformity value is 0.86, which is significantly larger than Example 2 with reasonable distribution plate spacing. This shows that the spacing between distribution plates has an important impact on the distribution effect of the distributor. Using the method for determining the spacing between distribution plates of the present invention can effectively avoid the "short circuit" problem of short-spacing distribution plates.

Comparative Example 6: 50,000 tons/year ethanol oxidation to acetaldehyde reactor (distributor with distribution plate in the second gas dispersion hood)

The distribution plate is an important gas distribution component of the distributor, and its location also has an important impact on the uniformity of gas distribution. Comparative Example 6 is based on the reactor described in Example 2, adjusting the position of the distribution plate into the second gas dispersion hood, that is, arranging a multi-layer distribution plate starting from the gas inlet of the second gas dispersion hood. The structure and spacing are the same as in Embodiment 2. The structure of this distributor is similar to the distributor disclosed in Chinese patent document CN105597655A, and can be equivalent to the application of this patent idea in the present invention.

Based on the same feeding conditions of Example 2, the gas distribution effect at the distributor outlet of Comparative Example 6 was calculated. The results are shown in Figures 23a and 23b. The area not shown in Figure 23b is the reflux area. As can be seen from Figure 23a, the velocity range fluctuates from -1.67 to 5.66m/s, the flow rate into the catalyst reaction layer is very large, and there is a large reflux area. The non-uniformity value is 2.06, which is approximately 10 times that of Example 2. , which is not conducive to chemical reactions. In addition, it can be seen from Figure 23b that there is a large recirculation area at the outlet of the distributor. According to the analogy of the calculation results, if the distributor disclosed in CN105597655A is applied to the present invention, it will be difficult to meet the requirements of chemical reactions for gas flow rate and distribution uniformity. This is mainly because this type of distributor arranges the distribution plate in the dispersion hood. When the gas passes through the dispersion hood, the main flow velocity of the gas in the central area is very large, resulting in severe backflow in the outer circle area below the distribution plate, reducing the uniformity of gas distribution. Compared with Embodiment 2 of the present invention, the above problem does not exist. This is because the present invention designs a connection structure in which the double-layer dispersion cover and the distribution plate assembly are sequentially combined. After the second-stage deceleration pre-distribution is completed, the built-in porous distribution plate is The third gas channel performs third-level uniform distribution, which can effectively improve the uniformity of gas distribution.

Comparative Example 7: Examine the gas distribution effect of Comparative Example 2 under the condition of fixed inlet pipe diameter and the influence of gas flow rate

Generally, the inlet pipe of the distributor is top-intake, but the gas distribution effect of this type of distributor is obviously limited by the gas flow rate. In order to illustrate this phenomenon, Comparative Example 7 is based on the reactor described in Comparative Example 2. The diameter of the inlet pipe is fixed and the gas flow rate is changed so that the average flow velocity distribution of the distributor outlet section is 0.1m/s and 0.5m/s. , 1m/s, 1.5m/s, 2m/s, 3m/s, 5m/s, 7m/s, and then analyze its impact on the unevenness of the distributor outlet through calculation. Figures 24, 25a-b, 26a-b, and 27a-b respectively show the outlet velocity distribution cloud diagrams when the average flow velocity distribution of the distributor outlet section is 0.1m/s, 1m/s, 3m/s, and 7m/s. It can be seen from Figure 24 that when the average flow velocity at the distributor outlet is 0.1m/s, there is no backflow at the distributor outlet, the gas is relatively uniform, and the non-uniformity is 0.44. When the average flow velocity at the distributor outlet is 1m/s, 3m/s and 7m/s respectively, the velocity cloud diagrams at the distributor outlet are shown in Figures 25a-b, 26a-b and 27a-b. It can be seen from the figure that there is backflow at the outlet of the distributor, and the flow rate range fluctuates greatly. The maximum flow rates are 3.24m/s, 9.27m/s, and 21.9m/s respectively, which are about 3 times the average flow rate, which is not conducive to the chemical industry. reaction. In addition, the outlet gas non-uniformity is 0.6, which is greater than 0.44 when the average outlet flow velocity is 0.1m/s. In order to further analyze the influence of flow rate on the gas unevenness at the distributor outlet, Figure 28 is a curve of the gas unevenness at the distributor outlet of Comparative Example 7 as a function of the outlet average flow rate. It can be seen from Figure 28 that when the average outlet flow velocity is 0.1m/s, the gas unevenness of the top air inlet distributor is a minimum value of 0.44. As the average outlet flow rate increases, the gas unevenness increases. This shows that the top-inlet distributor can achieve better distribution effects for small flow rates of gas, but when the gas flow rate is large, the gas distribution effect becomes worse. Comparing the graph of the change of gas unevenness at the distributor outlet with the average flow rate of the outlet in Example 1 of the present invention (Fig. 13), it can be clearly seen that using the distributor of the present invention, the side air intake and the double-layer dispersion cover The inlet gas undergoes expansion rectification and deceleration pre-distribution, which eliminates the impact of gas flow on the performance of the distributor, thereby greatly improving the applicability of the distributor.

Comparative Example 8: Examine the gas distribution effect of Comparative Example 2 under the condition of fixed gas flow rate and the influence of the diameter of the inlet pipe

Generally, the inlet pipe of the distributor is top-intake, but the gas distribution effect of this type of distributor is also obviously limited by the diameter of the inlet pipe. In order to illustrate this phenomenon, Comparative Example 8 is based on the reactor described in Comparative Example 2. The gas flow rate is fixed, and the diameter of the inlet pipe is changed to 130mm, 283mm, 566mm, and 849mm. Through calculation and analysis, it has no effect on the gas at the distributor outlet. Effect of uniformity. Figures 29a-b, 30a-b, 31, and 32 respectively show the outlet velocity distribution cloud diagrams when the diameter of the inlet pipe is 130mm, 283mm, 566mm, and 849mm. It can be seen from Figures 29a-b and 30a-b that when the distributor inlet pipe diameter is the smaller diameter of 130mm and 283mm, backflow occurs at the distributor outlet, and the flow rate range fluctuates greatly, and the maximum flow rate is 4.76m/s respectively. and 3.43m/s, which are about 5-6 times the average flow velocity, and the outlet gas non-uniformity is 0.99 and 0.86 respectively. This shows that when the diameter of the inlet pipe is small, the distribution effect of the air distributor from the top is poor, which is not conducive to chemical reactions. It can be seen from Figures 31 and 32 that when the distributor inlet pipe diameter is the larger diameter of 566mm and 849mm, there is no backflow at the distributor outlet, and the outlet gas unevenness is also the smaller value of 0.4 and 0.29 respectively. This shows that when the diameter of the inlet pipe is larger, the distributor that takes in air from the top can achieve better distribution results. In order to further analyze the influence of the diameter of the inlet pipe on the unevenness of the gas at the distributor outlet, Figure 33 shows the variation curve of the unevenness of the gas at the distributor outlet in Comparative Example 8 with the diameter of the inlet pipe. It can be seen from Figure 33 that when the diameter of the inlet pipe is 130mm, the gas unevenness of the top air inlet distributor is the maximum value of 0.99. As the diameter of the inlet pipe increases, the gas unevenness also decreases. When When the diameter of the inlet pipe is 849mm, the gas unevenness of the top air inlet distributor is the minimum value 0.29. This shows that the top-intake distributor can achieve better distribution effects for large inlet pipe diameters, but when the inlet pipe diameter decreases, the gas distribution effect becomes worse. Comparing the graph of the variation of gas unevenness at the distributor outlet with the diameter of the inlet pipe in Example 1 of the present invention (Fig. 13), it can be clearly seen that using the distributor of the present invention, the inlet is affected by the side air intake and the double-layer dispersion cover. The gas undergoes diffusion rectification and deceleration pre-distribution, which eliminates the impact of the diameter of the inlet pipe on the performance of the distributor, thereby greatly improving the applicability of the distributor.

Obviously, the above-mentioned embodiments are only examples for clear explanation and are not intended to limit the implementation. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. An exhaustive list of all implementations is neither necessary nor possible. The obvious changes or modifications derived therefrom are still within the protection scope of the present invention.

Claims (13)

1. A gas distributor, characterized in that it includes: The gradually expanding assembly includes a first gas dispersion cover and a second gas dispersion cover located inside the first gas dispersion cover. The second gas dispersion cover has a gas inlet and a gas outlet. Between the gas inlet and the gas A second gas channel is formed between the outlets, and the cross-sectional area of the second gas channel gradually increases along the gas flow direction; the inlet pipe of the reaction raw material gas is arranged on the first gas dispersion cover close to the second gas At the gas outlet of the dispersion cover, the space between the first gas dispersion cover and the second gas dispersion cover forms a first gas channel, and the first gas channel is connected with the second gas channel; and The distribution plate assembly includes at least two parallel and spaced gas distribution plates. The gas distribution plates are provided with a number of through holes. The distance Δh between two adjacent gas distribution plates satisfies: Among them, C _h is the gas jet convergence coefficient, the unit is m·s, and the value is 0.02~0.1. is the average gas flow velocity at the outlet section of the gas distributor, in m/s, φ is the porosity of the gas distribution plate; Δh is in mm; The gradually expanding component and the distribution plate component are arranged sequentially along the gas flow direction, and the maximum cross-sectional area of the second gas channel is not less than the area of the gas distribution plate. 2. The gas distributor according to claim 1, characterized in that the gas distribution plate is circular and its diameter _D0 satisfies: Among them, Q is the gas volume flow rate flowing through the gas reactor, the unit is m ³ /h; π is the pi ratio, the value is 3.1415926; D ₀ unit is mm; and/or, described is 0.1~2.5m/s; and/or, The value of φ is 0.3~0.5. 3. The gas distributor according to claim 2, wherein the through holes are arranged staggered at 60° on the gas distribution plate, and the through holes are round holes, and two adjacent through holes are arranged in a staggered manner at 60°. The hole center distance d satisfies: Among them, D ₃ is the diameter of the through hole, the unit is mm, and the value is 0.01 to 0.03D ₀ . 4. The gas distributor according to claim 1, wherein the shape of the through hole is a triangle, a square, a rectangle, a rhombus, a cross, a hexagon or an ellipse; and/or the through hole is Arranged in concentric circles, straight or staggered. 5. The gas distributor according to claim 1, characterized in that the number of the gas distribution plates is 3 to 6; and/or, The gas distribution plate is arranged perpendicular to the gas flow direction. 6. The gas distributor according to any one of claims 1 to 5, wherein the distribution plate assembly further includes a first cylinder, and the periphery of the gas distribution plate and the inner wall of the first cylinder are Connected, the internal space of the first cylinder forms a third gas channel, and the third gas channel is connected with the second gas channel. 7. The gas distributor according to claim 1, wherein the angle α between the second gas distribution cover and the cross section of the second gas channel is 30 to 70°. 8. The gas distributor according to claim 2, wherein the height _H of the second gas distribution cover satisfies: Wherein, B _h is the height coefficient of the second gas dispersion cover, which is taken as 0.5-0.8; α is the angle between the cross section of the second gas dispersion cover and the second gas channel, which is taken as 30-70°. 9. The gas distributor according to claim 7 or 8, characterized in that the angle α between the second gas dispersion cover and the cross section of the second gas channel is 45 to 65°. 10. The gas distributor according to claim 2, wherein the distance between the top of the first gas dispersion hood and the gas inlet of the second gas dispersion hood is not less than 0.25D ₀ . 11. The gas distributor according to claim 2, characterized in that there is at least one inlet pipe, and when there are more than two inlet pipes, the inlet pipes are symmetrically arranged on the first gas distributor. on the outer wall of the cover. 12. The gas distributor according to claim 11, wherein the diameter D _inlet or the equivalent diameter _De of the inlet pipe is 0.1 to 0.2 D ₀ ; and/or, The length L _inlet of the inlet pipe is 1.0～2.0D _inlet ; and/or, The distance h _inlet between the inlet pipe and the bottom surface of the first gas dispersion cover is 0 to 900 mm. 13. A gas-solid reactor, characterized by comprising the gas distributor according to any one of claims 1 to 12.