Gas distributor, gas-solid fluidized reactor and application and method

Abstract

The invention discloses a gas distributor, a gas-solid fluidized reactor and application and method, the gas distributor comprises a plurality of gas distribution units, the plurality of gas distribution units are arranged at intervals along the H direction, a plurality of H-direction intervals L between two adjacent gas distribution units are formed, and the plurality of H-direction intervals L are equal or are sequentially increased along the H direction; each gas distribution unit comprises a branch pipe with a gas inlet, the branch pipe is communicated with a plurality of branch pipes, and the branch pipe and each branch pipe are provided with a plurality of nozzles. The method can reduce the dosage of reaction raw materials, improves the product yield, is simple in process, and is easy to realize industrial production.

Description

Technical Field

[0001] The invention relates to the technical field of chemical raw material preparation, and in particular to a gas distributor, a gas-solid fluidized reactor, and an application and method thereof. Background Art

[0002] Isophthalonitrile (IPN), white needle crystals, slightly soluble in hot water, soluble in hot ethanol, ether, benzene, chloroform, etc., with a melting point of 163-165°C and a boiling point of 288°C, is the most in-demand variety among aromatic nitriles. It has two main uses. One is that tetrachloroisophthalonitrile (chlorothalonil) obtained by chlorination is a high-efficiency, low-toxic fungicide; the other is that metaphenylenediamine obtained by hydrogenation reaction is a resin curing agent with good performance, and is also a raw material for polyurethane resin and nylon resin. Among them, the fluidized bed gas phase ammoxidation method using fine particle catalyst is currently the most advanced method for producing isophthalonitrile. However, in order to improve the conversion rate and selectivity of the reaction in the prior art, a large amount of ammonia and oxygen are often required to be introduced into the production process. This will cause the intensification of side reactions such as ammonia combustion and deep oxidation, generate a large amount of N2 and COx, and cause waste of raw materials, as well as a reduction in the purity of IPN in the product, which will cause pressure for subsequent separation and is not conducive to its application in the production of high-end chemicals. Summary of the invention

[0003] The purpose of the present invention is to provide a gas distributor, a gas-solid fluidized reactor and its application and method, which have the advantages of reducing the amount of reaction raw materials (such as the reaction ammonia ratio), improving the product yield, and having a simple process and easy to realize industrial production.

[0004] In order to achieve the above object, the present invention provides a gas distributor on one hand, wherein the gas distributor comprises:

[0005] A plurality of air distribution units, wherein the plurality of air distribution units are arranged at intervals along the H direction, and a plurality of H-direction spacings L are formed between two adjacent air distribution units, and the plurality of H-direction spacings L are equal or increase sequentially along the H direction;

[0006] Each of the air distribution units comprises a branch pipe with an air inlet, the branch pipe is connected to a plurality of branch pipes, and a plurality of nozzles are arranged on the branch pipe and each of the branch pipes.

[0007] A second aspect of the present invention provides a gas-solid fluidized reactor, wherein a second gas distributor connected to a second gas phase inlet is provided at the bottom of the cavity of the gas-solid fluidized reactor, a first gas distributor is provided above the second gas distributor, the first gas distributor adopts the gas distributor of the present invention, and the gas inlet of the branch pipe of the first gas distributor is connected to the first gas phase inlet;

[0008] Preferably, the bottom opening of the main pipe of the first gas distributor is communicated with the first gas phase inlet.

[0009] The gas-solid fluidized reactor of the present invention is used in the ammoxidation reaction of aromatic hydrocarbons.

[0010] The present invention provides a method for ammoxidation of aromatic hydrocarbons, the method adopting the gas-solid fluidized reactor of the present invention and comprising:

[0011] 1) introducing a mixed raw material containing ammonia and aromatic hydrocarbons into the second gas phase inlet, dispersing into the cavity through the second gas distributor to contact with the oxygen-containing gas carried by the catalyst to generate an early aromatic nitrile-containing stream;

[0012] 2) introducing oxygen-containing gas into the first gas phase inlet, passing through the first gas distributor and dispersing along the axial direction of the cavity to contact with the early aromatic nitrile-containing flow to generate a late aromatic nitrile-containing flow.

[0013] Through the above technical scheme, the gas distributor of the present invention can control the gas material content in different reaction stages and improve the yield of the target product. Further, the present invention can solve the problems in the prior art that the ammonia ratio and air ratio required for ammonia oxidation are too large, the raw material utilization efficiency is not high, and the product purity is low due to numerous side reactions. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is a schematic structural diagram of a gas-solid fluidized reactor according to a specific embodiment;

[0015] Figure 2 It is a schematic diagram of the structure of the annular partition in the post-reaction section;

[0016] Figure 3 yes Figure 1 Schematic diagram of the structure of the gas distributor;

[0017] Figure 4 It is a structural schematic diagram of an air distribution unit;

[0018] Figure 5 is a schematic diagram of the structure of another air distribution unit;

[0019] Figure 6 It is a schematic diagram of the radial cross section of a branch pipe or a branch pipe;

[0020] Figure 7 It is a schematic diagram of the structure of the air distributor and the aromatic hydrocarbon / ammonia distributor in the prior art of Comparative Examples 1 and 2.

[0021] Description of Reference Numerals

[0022] 1 front reaction section; 2 rear reaction section; 3 internal circulation zone; 4 annular partition; 5 cylindrical lifting section; 6 gas-solid separation section; 7 cyclone separator; 8 external circulation pipe; 9 catalyst regenerator; 10 second gas distributor; 11 first gas distributor; 12 second gas phase inlet; 13 first gas phase inlet; 14 air feed port; 15 outlet; 401 through hole; 402 annular shell; 1101 main pipe; 1102 branch pipe; 1103 branch pipe; 1104 nozzle. DETAILED DESCRIPTION

[0023] The specific implementation of the present invention is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the present invention, and is not used to limit the present invention.

[0024] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0025] In the present invention, unless otherwise specified, directional words such as "up, down, left, right" generally refer to up, down, left, right as shown in the reference drawings; "inside and outside" refer to inside and outside relative to the outline of each component itself.

[0026] The first aspect of the present invention discloses a gas distributor, such as Figure 1 or Figure 3 As shown, the gas distributor includes:

[0027] A plurality of air distribution units, the plurality of air distribution units are arranged at intervals along the H direction, and a plurality of H-direction spacings L are formed between two adjacent air distribution units, and the plurality of H-direction spacings L are equal or increase successively along the H direction;

[0028] Each air distribution unit includes a branch pipe 1102 with an air inlet, and the branch pipe 1102 is connected to a plurality of branch pipes 1103 . A plurality of nozzles 1104 are arranged on the branch pipe 1102 and each branch pipe 1103 .

[0029] The gas distributor of the present invention can control the gas material content in different reaction stages and improve the yield of the target product.

[0030] In some embodiments of the present invention, along the H direction, a plurality of H-direction spacings L are sequentially named L1...L n , where L n :L n-1 =1~1.5.

[0031] In some embodiments of the present invention, the total porosity of the gas distributor is 0.1% to 10%.

[0032] In some embodiments of the present invention, the plurality of nozzles 1104 are arranged at intervals along the length direction of each branch pipe 1102, and two adjacent nozzles 1104 on the same branch pipe 1102 are arranged symmetrically about the axis of the branch pipe 1102, and as Figure 6 As shown, it has an angle γ;

[0033] Multiple nozzles 1104 are arranged at intervals along the length direction of each branch pipe 1103, and two adjacent nozzles 1104 on the same branch pipe 1103 are arranged symmetrically about the axis of the branch pipe 1103, and as shown in FIG. Figure 6 As shown, there is an angle γ.

[0034] In some embodiments of the present invention, γ is preferably 30-120°.

[0035] In some embodiments of the present invention, the gas distributor also includes a main pipe 1101 arranged in the H direction, the bottom end opening of the main pipe 1101 is used for air intake, and in each gas distribution unit, a plurality of branch pipes 1102 are provided, and the plurality of branch pipes 1102 are radially arranged on the side of the main pipe 1101 and connected to the main pipe 1101.

[0036] In some embodiments of the present invention, preferably, in each gas distribution unit, the number of branch pipes 1102 is 4 to 16, and the angle α between the axis of each branch pipe 1102 and the axis of the main pipe 1101 is 30 to 90°, and more preferably α is 30-75°. In the present invention, based on the above disclosure, the above-mentioned preferred method can control the oxygen content in different reaction stages in the ammoxidation reaction, inhibit deep oxidation, improve the quality of gas-solid fluidization, and avoid uneven reaction and local overheating of the bed.

[0037] In some embodiments of the present invention, in each air distribution unit, a plurality of branch pipes 1103 are distributed on both sides of the branch pipe 1102 .

[0038] In other embodiments of the present invention, a plurality of branch pipes 1103 are radially distributed on the side of the branch pipe 1102 .

[0039] In other embodiments of the present invention, the branch pipe 1103 is annular (eg Figure 4 Ring or Figure 5 A plurality of annular branch pipes 1103 are concentrically arranged, each branch pipe 1102 is extended in the radial direction of the branch pipe 1103 and is connected with the annular branch pipe, the inner end of the branch pipe 1102 is connected with the side of the main pipe 1101, and the end of the outer end is set to be closed.

[0040] The second aspect of the present invention discloses a gas-solid fluidized reactor, such as Figure 1 The bottom of the cavity of the gas-solid fluidized reactor is provided with a second gas distributor 10 connected to a second gas phase inlet 12, and a first gas distributor 11 is provided above the second gas distributor 10. The first gas distributor 11 adopts the gas distributor of the present invention, and the gas inlet of the branch pipe 1102 of the first gas distributor 11 is connected to the first gas phase inlet 13; preferably, the bottom end opening of the main pipe 1101 of the first gas distributor 11 is connected to the first gas phase inlet 13. In the present invention, there is no special requirement for the second gas distributor 10, and a conventional gas distributor in the prior art, such as in an ammonia oxidation reaction, can be used.

[0041] In some embodiments of the present invention, the chamber includes, from bottom to top, a front reaction section 1, a rear reaction section 2 and a gas-solid separation section 6 that are interconnected, the second gas distributor 10 is installed in the front reaction section 1, and the first gas distributor 11 is installed in the rear reaction section 2.

[0042] In some embodiments of the present invention, a rapid lifting structure is provided in the cavity; preferably, the rapid lifting structure comprises a tapered upwardly contracting port provided at the outlet end of the post-reaction section 2, the small end of the tapered port extending toward the gas-solid separation section to form a columnar lifting section 5, and the cross-sectional area of ​​the columnar lifting section 5 is 1 / 5 to 4 / 5 of the cross-sectional area of ​​the post-reaction section 2. In this way, the linear velocity of the upward movement of the gas and solid can be accelerated, firstly, back-mixing can be avoided, and secondly, the residence time can be shortened, and the reduction of the product yield and purity caused by deep oxidation can be avoided in the oxidation reaction.

[0043] In some embodiments of the present invention, the cross-sectional area of ​​the cavity is such that the gas-solid separation section 6> the rear reaction section 2=the front reaction section 1, and the front reaction section and the rear reaction section are provided with heat exchange components, such as heat exchange tubes connecting the heat exchangers; a cyclone separator 7 is provided in the cavity of the gas-solid separation section for performing gas-solid separation on the later aromatic nitrile-containing flow from the rear reaction section and discharging the flow through the outlet 15 to discharge the gas-solid fluidized bed reactor; the top of the cylindrical lifting section 5 is spaced apart with a downwardly curved arc baffle.

[0044] In some embodiments of the present invention, an annular partition 4 is provided in the rear reaction section 2, and the first gas distributor 11 is provided in the area surrounded and defined by the annular partition 4, and the annular gap between the annular partition 4 and the cavity wall of the rear reaction section 2 forms an internal circulation zone 3.

[0045] In order to strengthen the internal circulation in the cavity, in some embodiments of the present invention, a plurality of through holes 401 are preferably opened on the side wall of the annular partition 4, and the through holes 401 allow solid particles in the defined area inside the annular partition 4 to flow into the internal circulation area 3 through the through holes 401.

[0046] In some embodiments of the present invention, Figure 1-Figure 2As shown, the bottom end of the annular partition 4 is preferably connected to an annular shell 402, the annular shell 402 is formed as a bottom opening that tapers upward, and the angle β between the side wall of the annular shell 402 and the side wall of the annular partition 4 is 30-60°.

[0047] In some embodiments of the present invention, the cross-sectional area of ​​the inner circulation zone 3 is preferably 1 / 10 to 1 / 2 of the cross-sectional area of ​​the post-reaction section 2 .

[0048] In some embodiments of the present invention, Figure 1 As shown, the gas-solid fluidized bed reactor is provided with an external circulation unit, which includes a catalyst regenerator 9 and is connected to the front reaction section 1 and the gas-solid separation section 6, and is used to draw out part of the catalyst in the gas-solid separation section 6 and send it to the front reaction section 1 after regeneration.

[0049] In some embodiments of the present invention, the external circulation unit includes an external circulation pipe 8 connecting the gas-solid separation section and the pre-reaction section, and a catalyst regenerator 9 is arranged on the pipeline of the external circulation pipe. For example, the catalyst regenerator 9 is selected from a catalyst oxygenator, and the catalyst oxygenator is provided with an exhaust gas discharge pipe and an air feed port 14 for oxygenating the catalyst to be regenerated. The gas-solid fluidized reactor of the present invention adopts a double circulating fluidized bed form combining internal circulation and external circulation of catalyst particles to improve the product yield.

[0050] The fourth aspect of the present invention discloses the application of the gas-solid fluidized reactor of the present invention in the ammoxidation reaction of aromatic hydrocarbons.

[0051] A fifth aspect of the present invention discloses a method for ammoxidation of aromatic hydrocarbons, which method adopts the gas-solid fluidized reactor of the present invention and comprises:

[0052] 1) A mixed raw material containing ammonia and aromatic hydrocarbons is introduced into the second gas phase inlet 12, dispersed into the cavity through the second gas distributor 10 to contact with the oxygen-containing gas carried by the catalyst to generate an early aromatic nitrile-containing flow; step 1) mainly utilizes the oxygen carried by the catalyst for the initial reaction, which is mainly used to generate reaction intermediates and reduce the generation of CO2.

[0053] 2) The oxygen-containing gas is introduced into the first gas phase inlet 13, and is dispersed in intervals along the axial direction of the cavity through the first gas distributor 11 to contact with the previous aromatic nitrile-containing flow to generate the later aromatic nitrile-containing flow. Step 2) is mainly to continue the ammoxidation of the intermediate product generated in step 1). The first gas distributor 11 not only provides the oxygen required for the reaction in steps along the axial direction, but also improves the quality of gas-solid fluidization, avoids uneven reaction and local overheating of the bed, and further inhibits back mixing.

[0054] In the middle and late stages of the rear reaction section, part of the aromatic nitrile flow moves upward through the necking and columnar lifting section 5, and part of it moves downward through the inner circulation zone 3; the solid catalyst exiting the inner circulation zone 3 participates in the ammonia oxidation reaction in the front reaction section 1 again, and the catalyst from the inner circulation carries part of the gaseous oxygen introduced from the rear reaction section 2, thereby increasing the oxygen content in the front reaction section 1 to promote the reaction. In addition, the catalyst circulating inside and outside is also a heat regulator, which is safer in operation.

[0055] The later aromatic nitrile-containing flow moving upward is separated into gas and solid in the gas-solid separation section 6, and the solid catalyst moves downward and a part of it is recycled and regenerated through the external circulation pipe 8 and then fed to the front reaction section; the gas carries a small amount of solid particles and moves upward, and is separated into gas and solid again through the cyclone separator 7 arranged at the top of the gas-solid fluidized reactor, and flows out from the outlet 15 at the top of the gas phase product device, and after washing, filtering, dehydration, drying and other processes, the target product aromatic nitrile is finally obtained.

[0056] The catalyst particles entering the circulation pipe 8 enter the catalyst oxygenator along the pipeline, and the air feed port 14 introduces air into the catalyst oxygenator to oxygenate the reacted catalyst. The oxygenated catalyst enters the front reaction section at the bottom of the reactor through the pipeline to undergo ammonia oxidation reaction again. The function of the catalyst oxygenator is to regenerate the catalyst that has lost lattice oxygen, and the exhaust gas leaves the oxygenator without entering the front reaction section 1 along with the oxygenated catalyst.

[0057] In some embodiments of the aromatic hydrocarbon ammoxidation of the present invention, part of the flow in the rear reaction section is refluxed to the front reaction section 1 through the internal circulation zone 3 .

[0058] In some embodiments of the aromatic ammoxidation of the present invention, the total catalyst weight loading (WWH) is 0.07 to 0.2 h -1 , preferably 0.09~0.15h -1 .

[0059] In some embodiments of the ammoxidation of aromatic hydrocarbons of the present invention, step 1) is carried out in the pre-reaction section 1, and the temperature of the pre-reaction section 1 is controlled to be 350-410°C.

[0060] In some embodiments of the aromatic hydrocarbon ammoxidation of the present invention, step 2) is carried out in the post-reaction section 2, and the temperature of the pre-reaction section 1 is controlled to be 400-450°C.

[0061] In some embodiments of the aromatic hydrocarbon ammoxidation of the present invention, the temperature of the columnar lifting section 5 and the inner circulation zone 3 is controlled to be 360-400°C.

[0062] In some embodiments of the aromatic ammoxidation of the present invention, the temperature of the catalyst oxygenator is controlled to be 460-500°C.

[0063] In some embodiments of the ammoxidation of aromatic hydrocarbons of the present invention, the molar ratio of the feeds of the second gas distributor 10 and the first gas distributor 11 is aromatic hydrocarbon: ammonia: air = 1: 3 to 8: 20 to 40. In the present invention, aromatic hydrocarbons include but are not limited to o-xylene, m-xylene, p-xylene or 4-nitro o-xylene.

[0064] In some embodiments of the aromatic hydrocarbon ammoxidation of the present invention, preferably, the ratio of m-xylene: ammonia: air is 1:4-5:25-30.

[0065] The advantages of the present invention are described below by way of examples, but the present invention is not limited thereto.

[0066] The following examples 1-3 are Figure 1-Figure 6 The gas-solid fluidized reactor shown in the figure is carried out, and embodiments 4-8 are modified on the basis of embodiment 1, and the differences have been described in each embodiment;

[0067] The gas-solid fluidized reactor adopts a double-circulating fluidized bed structure combining internal and external circulation of catalyst particles. Specifically, the cavity of the reactor includes a front reaction section 1, a rear reaction section 2 and a gas-solid separation section 6 from bottom to top. A cyclone separator is arranged on the top of the gas-solid separation section 6. The front reaction section 1 and the rear reaction section 2 are provided with heat exchange pipes of a heat exchanger.

[0068] The front reaction section 1 is equipped with a second gas distributor 10 connected to the second gas phase inlet 12 (the second gas distributor 10 in this embodiment adopts a conventional gas distributor in the ammonia oxidation reaction in the prior art), and the rear reaction section 2 is equipped with a first gas distributor 11 connected to the first gas phase inlet 13; the outlet end of the rear reaction section 2 is arranged as a tapered opening that gradually contracts upward, and the small end of the tapered opening extends toward the gas-solid separation section to form a columnar lifting section 5, and the top of the columnar lifting section 5 is spaced apart with a downwardly curved arc baffle;

[0069] The gas-solid separation section 6 and the front reaction section 1 are connected through an external circulation pipe 8 arranged outside the reactor, and a catalyst oxygenator is arranged on the external circulation pipeline to form an external circulation pipeline for catalyst particles; an annular baffle 4 with a plurality of through holes 401 opened on the side wall is arranged in the rear reaction section 2, and the first gas distributor 11 is located in the area surrounded and limited by the annular baffle 4, and the annular gap between the annular baffle 4 and the cavity wall of the rear reaction section 2 forms an internal circulation zone 3, and the bottom end of the annular baffle is connected to an annular shell 402 with a bottom opening that is tapered upward.

[0070] The first gas distributor 11 includes: a plurality of gas distribution units and a main pipe 1101 arranged in the H direction and connected to the first gas phase inlet 13, and the plurality of gas distribution units are arranged at intervals along the axial direction of the main pipe 1101;

[0071] Each air distribution unit includes multiple branch pipes 1103 and multiple branch pipes 1102. The inner ends of the multiple branch pipes are arranged at intervals along the circumferential direction on the side of the main pipe and are connected to the main pipe 1101, and the ends of the outer ends are set to be closed. The branch pipe 1103 is annular, and the multiple branch pipes 1103 are concentrically arranged. Each branch pipe 1102 extends and is connected along the radial direction of the branch pipe 1103. Multiple nozzles 1104 are arranged on each branch pipe 1102 and each branch pipe 1103. The multiple nozzles 1104 are arranged at intervals along the length direction of the pipe (branch pipe or branch pipe), and two adjacent nozzles on the same pipe are arranged symmetrically about the axis of the pipe.

[0072] The method for ammoxidation of aromatic hydrocarbons using the gas-solid fluidized reactor comprises: 1) introducing a mixed raw material containing ammonia and aromatic hydrocarbons into the second gas phase inlet 12; 2) introducing an oxygen-containing gas into the first gas phase inlet 13.

[0073] The general process of the method includes: the catalyst is filled at the bottom of the reactor, ammonia and gasified aromatic hydrocarbons are introduced into the reactor through the ammonia distributor (second gas distributor 10, with an opening rate of 0.045%) located in the front reaction section 1, contacting with the catalyst in the front reaction section 1 and carrying out a preliminary reaction. The gas-solid mixture enters the rear reaction section 2 upward, and air (oxygen) is supplemented into the rear reaction section 2 through the oxygen distributor (first gas distributor 11), so that the unreacted aromatic hydrocarbon raw materials and intermediate products from the front reaction section 1 continue to undergo ammonia oxidation reaction (post-reaction). A part of the gas-solid mixture exiting the rear reaction section 2 moves upward through the rapid lifting structure, and a part moves downward through the inner circulation zone 3. The solid catalyst exiting the inner circulation zone 3 participates in the ammonia oxidation reaction in the front reaction section again; the gas-solid mixture moving upward through the rapid lifting structure is separated into gas and solid in the gas-solid separation section 6, the solid catalyst moves downward and circulates through the external circulation pipe 8, the catalyst particles enter the catalyst oxygenator along the pipeline, and after oxygenation, enter the front reaction section at the bottom of the reactor through the pipeline to undergo ammonia oxidation reaction again. The gas after gas-solid separation in the gas-solid separation section 6 carries a small amount of solid particles and moves upward, and is separated from the solid again by the cyclone separator 7 at the top of the reactor. The gas phase product flows out from the outlet 15 at the top of the device and enters the product collecting device. After washing, filtering, dehydration, drying and other processes, the target product aromatic nitrile is finally obtained.

[0074] It should be noted that the present invention can use a catalyst V with silicon dioxide as a carrier and vanadium, chromium, boron, etc. as the main active components. 1.0 Cr 0.9 B 0.5 P 0.5 Ti 0.1 Mo 0.1 W 0.05 K 0.05 / SiO2, the average particle size of the catalyst is 200 mesh.

[0075] Example 1

[0076] Structural parameters: the cross-sectional area of ​​the inner circulation zone 3 is 1 / 8 of the cross-sectional area of ​​the post-reaction zone 2; the angle β between the side wall of the annular shell 402 and the side wall of the annular partition 4 is 45°; the oxygen gas distributor (first gas distributor 11) located in the post-reaction zone is arranged along the gas flow direction, and 4 layers of gas distribution units are arranged along the main pipe, and the spacing L increases successively from H to L. n :L n-1 =1.2 times; 6 branch pipes are symmetrically arranged along the main pipe axis on each layer, and the angle α with the main pipe is 60°; every two adjacent branch pipes are connected by 6 annular branch pipes, and the angle γ between two adjacent nozzles on the same pipe is 60°, and the total opening rate of the oxygen gas distributor is 2%; the cross-sectional area of ​​the cylindrical lifting section 5 is 1 / 2 of the cross-sectional area of ​​the post-reaction section 2.

[0077] Method parameters: temperature of front reaction section 1 385℃, temperature of rear reaction section 2 425℃, temperature of columnar lifting section 5 380℃, temperature of inner circulation zone 3 380℃, temperature of catalyst oxygenator 470℃; total catalyst weight load 0.10h -1 ; The molar ratio of the feeds to the ammonia gas distributor (the second gas distributor 10) and the oxygen gas distributor (the first gas distributor 11) is m-xylene:ammonia:air=1:4:26.

[0078] The reaction has an m-xylene conversion rate of 99.6%, an isophthalonitrile selectivity of 85.1%, and a CO2 selectivity of 7.3%.

[0079] Example 2

[0080] Structural parameters: the cross-sectional area of ​​the inner circulation zone 3 is 1 / 4 of the cross-sectional area of ​​the post-reaction zone 2; the angle β between the side wall of the annular shell 402 and the side wall of the annular partition 4 is 60°; the oxygen gas distributor (first gas distributor 11) located in the post-reaction zone is arranged along the gas flow direction, and 4 layers of gas distribution units are arranged along the main pipe, and the spacing L increases successively from H to L. n :L n-1 =1.5 times; 10 branches are arranged symmetrically along the main pipe axis on each layer, and the angle α with the main pipe is 30°; every two adjacent branches are connected by 6 annular branch pipes, the angle γ between two adjacent nozzles on the same pipe is 60°, and the total opening rate of the oxygen gas distributor is 6%; the cross-sectional area of ​​the cylindrical lifting section 5 is 4 / 5 of the cross-sectional area of ​​the post-reaction section 2.

[0081] Method parameters: front reaction section 1 temperature 400℃, rear reaction section 2 temperature 425℃, column riser section 5 temperature 380℃, inner circulation zone 3 temperature 380℃, catalyst oxygenator temperature 470℃; total catalyst weight load 0.15h -1; The molar ratio of the feeds to the ammonia gas distributor (the second gas distributor 10) and the oxygen gas distributor (the first gas distributor 11) is m-xylene:ammonia:air = 1:4:30.

[0082] The reaction has an m-xylene conversion rate of 99.0%, an isophthalonitrile selectivity of 82.3%, and a CO2 selectivity of 10.6%.

[0083] Example 3

[0084] Structural parameters: the cross-sectional area of ​​the inner circulation zone 3 is 1 / 6 of the cross-sectional area of ​​the post-reaction zone 2; the angle β between the side wall of the annular shell 402 and the side wall of the annular partition 4 is 35°; the oxygen gas distributor (first gas distributor 11) located in the post-reaction zone is arranged along the gas flow direction, and 6 layers of gas distribution units are arranged along the main pipe, with equal spacing L in the H direction, L n :L n-1 =1 times; 15 branches are arranged symmetrically along the main pipe axis on each layer, and the angle α with the main pipe is 75°; every two adjacent branches are connected by 6 annular branch pipes, the angle γ between two adjacent nozzles on the same pipe is 110°, and the total opening rate of the oxygen gas distributor is 9%; the cross-sectional area of ​​the cylindrical lifting section 5 is 1 / 5 of the cross-sectional area of ​​the post-reaction section 2.

[0085] Method parameters: temperature of front reaction section 1 385℃, temperature of rear reaction section 2 425℃, temperature of columnar lifting section 5 380℃, temperature of inner circulation zone 3 380℃, temperature of catalyst oxygenator 470℃; total catalyst weight load 0.10h -1 ; The molar ratio of the feeds to the ammonia gas distributor (the second gas distributor 10) and the oxygen gas distributor (the first gas distributor 11) is m-xylene:ammonia:air=1:5:28.

[0086] The reaction has an m-xylene conversion rate of 99.9%, an isophthalonitrile selectivity of 85.3%, and a CO2 selectivity of 6.9%.

[0087] Example 4

[0088] The difference from Example 1 is that L n :L n-1 =2 times.

[0089] The reaction has an m-xylene conversion rate of 99.5%, an isophthalonitrile selectivity of 79.6%, and a CO2 selectivity of 13.4%.

[0090] Example 5

[0091] Different from Example 1, the angle β between the side wall of the annular shell 402 and the side wall of the annular partition 4 is 75°, three branch pipes are symmetrically arranged along the main pipe axis on each layer, and the angle α with the main pipe is 90°, and the angle γ between two adjacent nozzles on the same pipe is 135°.

[0092] The reaction has an m-xylene conversion rate of 99.3%, an isophthalonitrile selectivity of 77.1%, and a CO2 selectivity of 15.6%.

[0093] Example 6

[0094] Different from the first embodiment, the annular partition plate 4 and the annular shell 402 are not arranged in the cavity, that is, there is no inner circulation zone 3.

[0095] The reaction has an m-xylene conversion rate of 99.9%, an isophthalonitrile selectivity of 81.7%, and a CO2 selectivity of 11.2%.

[0096] Example 7

[0097] The difference from Example 1 is that the external circulation pipe 8 and the catalyst oxygenator are not provided, and the annular partition plate 4 and the annular shell 402 are not provided in the cavity, that is, the catalyst particle internal circulation and external circulation process are not adopted;

[0098] The reaction has an m-xylene conversion rate of 98.7%, an isophthalonitrile selectivity of 69.4%, and a CO2 selectivity of 23.5%.

[0099] Example 8

[0100] The difference from Example 1 is that the molar ratio of the feeds of the ammonia gas distributor (the second gas distributor 10) and the oxygen gas distributor (the first gas distributor 11) is p-xylene: ammonia: air = 1:5:30;

[0101] The reaction has a xylene conversion rate of 99.5%, a terephthalonitrile selectivity of 88.1%, and a CO2 selectivity of 7.1%.

[0102] Comparative Example 1

[0103] A conventional fine-particle fluidized bed ammonia oxidation reactor is used. The size of the reactor is the same as that of Example 1, except that there is no distinction between the front reaction section 1, the rear reaction section 2, and the inner circulation zone 3. There is also no outer circulation pipe 8, catalyst oxygenator, and rapid lifting structure. The reaction is completed in the same fluidized bed reaction area. The reactor is sequentially provided with an air inlet pipe, an air distributor (upper porosity 1.5%, lower porosity 0.15%, wherein the air distributor is a plate distributor with a short tube connected to the bottom; the lower porosity refers to the ratio of the opening at the lower end of the short tube to the cross-sectional area of ​​the reactor; the upper porosity is the opening at the upper end of the short tube, that is, the ratio of the opening area of ​​the distribution plate to the cross-sectional area of ​​the reactor), and an aromatics / ammonia distributor (porosity 0.045%), and the structure is shown in the figure below. Figure 7As shown, a settling zone and a cyclone separator are arranged on the upper part of the reactor. The separated solid catalyst particles return to the fluidized bed layer, and the gas phase product flows out from the top outlet and enters the product collecting device. After washing, filtering, dehydration, drying and other processes, the target product isophthalonitrile is finally obtained.

[0104] Reaction temperature 415℃, total catalyst weight loading 0.08h -1 ; The molar ratio of the feed to the ammonia gas distributor and the oxygen gas distributor is m-xylene:ammonia:air = 1:7:40.

[0105] The reaction has an m-xylene conversion rate of 95.6%, an isophthalonitrile selectivity of 76.1%, and a CO2 selectivity of 17.5%.

[0106] Comparative Example 2

[0107] Different from Example 1, the ammonia gas distributor (second gas distributor 10) and the oxygen gas distributor (first gas distributor 11) both adopt the gas distributor form in the prior art, and the structure is schematically shown as follows: Figure 7 As shown, the feed molar ratio of m-xylene:ammonia:air = 1:7:36.

[0108] The reaction has an m-xylene conversion rate of 96.3%, an isophthalonitrile selectivity of 78.3%, and a CO2 selectivity of 15.1%.

[0109] Comparative Example 3

[0110] The difference from Comparative Example 1 is that the molar ratio of the feeds to the ammonia gas distributor and the oxygen gas distributor is p-xylene: ammonia: air = 1:7:40;

[0111] The reaction has a xylene conversion rate of 98.3%, an isophthalonitrile selectivity of 86.7%, and a CO2 selectivity of 8.5%.

[0112] The preferred embodiments of the present invention are described in detail above in conjunction with the accompanying drawings, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various specific technical features in any appropriate manner. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations. However, these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A gas distributor, characterized in that: The gas distributor comprises: A plurality of air distribution units, wherein the plurality of air distribution units are arranged at intervals along the H direction, and a plurality of H-direction spacings L are formed between two adjacent air distribution units, and the plurality of H-direction spacings L are equal or increase sequentially along the H direction; Each of the air distribution units comprises a branch pipe (1102) having an air inlet, the branch pipe (1102) is connected to a plurality of branch pipes (1103), and a plurality of nozzles (1104) are arranged on the branch pipe (1102) and each of the branch pipes (1103).

2. The gas distributor according to claim 1, characterized in that Along the H direction, the plurality of H-direction spacings L are named L1...L n , where L n :L n-1 =1~1.5; and / or The total opening rate of the gas distributor is 0.1% to 10%.

3. The gas distributor according to claim 1, characterized in that: The plurality of nozzles (1104) are arranged at intervals along the length direction of each branch pipe (1102), and two adjacent nozzles (1104) on the same branch pipe (1102) are arranged symmetrically about the axis of the branch pipe (1102) and have an included angle γ; and / or The plurality of nozzles (1104) are arranged at intervals along the length direction of each branch pipe (1103), and two adjacent nozzles (1104) on the same branch pipe (1103) are arranged symmetrically about the axis of the branch pipe (1103) and have an angle γ, preferably γ is 30 to 120°.

4. The gas distributor according to claim 1, characterized in that The gas distributor further comprises a main pipe (1101) arranged in the H direction, the bottom end of the main pipe (1101) is opened for air intake, and in each of the gas distribution units, a plurality of branch pipes (1102) are provided, and the plurality of branch pipes (1102) are radially arranged on the side of the main pipe (1101) and are connected to the main pipe (1101); Preferably, in each of the air distribution units, the number of the branch pipes (1102) is 4 to 16, and the angle α between the axis of each branch pipe (1102) and the axis of the main pipe (1101) is 30 to 90°, more preferably α is 30-75°.

5. The gas distributor according to claim 1 or 4, characterized in that: In each of the air distribution units, a plurality of branch pipes (1103) are distributed on both sides of the branch pipe (1102), or The plurality of branch pipes (1103) are radially distributed on the side of the branch pipe (1102).

6. The gas distributor according to claim 1 or 4, characterized in that: The branch pipe (1103) is annular in shape, and each branch pipe (1102) is extended along the radial direction of the branch pipe (1103). The inner end of the branch pipe (1102) is connected to the side of the main pipe (1101), and the end of the outer end is set to be closed.

7. A gas-solid fluidized reactor, characterized in that: A second gas distributor (10) connected to a second gas phase inlet (12) is provided at the bottom of the cavity of the gas-solid fluidized reactor, a first gas distributor (11) is provided above the second gas distributor (10), the first gas distributor (11) is a gas distributor according to any one of claims 1 to 6, and the gas inlet of the branch pipe (1102) of the first gas distributor (11) is connected to the first gas phase inlet (13); Preferably, the bottom opening of the main pipe (1101) of the first gas distributor (11) is connected to the first gas phase inlet (13).

8. The gas-solid fluidized bed reactor according to claim 7, characterized in that: The chamber comprises, from bottom to top, a front reaction section (1), a rear reaction section (2) and a gas-solid separation section (6) which are interconnected, the second gas distributor (10) being installed in the front reaction section (1), and the first gas distributor (11) being installed in the rear reaction section (2); and / or The cavity is provided with a rapid lifting structure for shortening the residence time of the material in the post-reaction section; Preferably, the rapid lifting structure comprises an upwardly tapering constriction arranged at the outlet end of the post-reaction section (2); More preferably, the small end of the necking portion extends toward the gas-solid separation section to form a cylindrical lifting section (5); More preferably, the cross-sectional area of ​​the cylindrical lifting section (5) is 1 / 5 to 4 / 5 of the cross-sectional area of ​​the post-reaction section (2).

9. The gas-solid fluidized bed reactor according to claim 8, characterized in that: An annular baffle (4) is arranged in the post-reaction section (2), the first gas distributor (11) is arranged in an area surrounded and defined by the annular baffle (4), and an annular gap between the annular baffle (4) and the cavity wall of the post-reaction section (2) forms an inner circulation area (3); Preferably, A plurality of through holes (401) are provided on the side wall of the annular partition (4), and the through holes (401) enable solid particles in a defined area around the annular partition (4) to flow into the inner circulation area (3) through the through holes; and / or The bottom end of the annular baffle (4) is connected to an annular shell (402), the annular shell (402) is formed as a bottom opening that tapers upward, and the angle β between the side wall of the annular shell (402) and the side wall of the annular baffle (4) is 30 to 60°; and / or The cross-sectional area of ​​the inner circulation zone (3) is 1 / 10 to 1 / 2 of the cross-sectional area of ​​the post-reaction section (2).

10. The gas-solid fluidized bed reactor according to claim 8 or 9, characterized in that: The gas-solid fluidized bed reactor is provided with an external circulation unit, which includes a catalyst regenerator (9) and is connected to the pre-reaction section (1) and the gas-solid separation section (6), and is used to draw out part of the catalyst in the gas-solid separation section (6), regenerate it and then send it to the pre-reaction section (1); preferably, the catalyst regenerator (9) is selected from a catalyst oxygenator.

11. Use of the gas-solid fluidized reactor according to any one of claims 7 to 10 in the ammoxidation reaction of aromatic hydrocarbons.

12. A method for the ammoxidation of aromatic hydrocarbons, characterized in that: The method adopts the gas-solid fluidized reactor according to any one of claims 7 to 10, and comprises: 1) introducing a mixed raw material containing ammonia and aromatic hydrocarbons into the second gas phase inlet (12), dispersing into the cavity through the second gas distributor (10) to contact with the oxygen-containing gas carried by the catalyst to generate an early aromatic nitrile-containing stream; 2) introducing oxygen-containing gas into the first gas phase inlet (13), passing through the first gas distributor (11) and being dispersed along the axial direction of the cavity to come into contact with the early aromatic nitrile-containing flow to generate a late aromatic nitrile-containing flow.

13. The method according to claim 12, wherein: Reflux part of the solid catalyst in the rear reaction section to the front reaction section (1) through the internal circulation zone (3); and / or Regenerating part of the catalyst in the gas-solid separation section (6) through an external circulation unit and feeding the regenerated catalyst into the front reaction section; and / or The total catalyst weight load is 0.07~0.2h -1 , preferably 0.09~0.15h -1 .

14. The method according to claim 13, wherein: Step 1) is carried out in the pre-reaction section (1), and the temperature of the pre-reaction section (1) is controlled to be 350-410° C.; and / or Step 2) is carried out in the post-reaction section (2), and the temperature of the pre-reaction section (1) is controlled to be 400-450° C.; and / or Controlling the temperature of the columnar lifting section (5) and the inner circulation zone (3) to be 360-400° C.; and / or Control the temperature of the catalyst oxygenator to 460-500°C; and / or The molar ratio of the feeds of the second gas distributor (10) and the first gas distributor (11) is aromatic hydrocarbon: ammonia: air = 1:3-8:20-40; The preferred ratio of m-xylene: ammonia: air is 1:4-5:25-30.

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