Ammonia oxidation coupling strengthening device and method for producing aromatic nitrile and application of ammonia oxidation coupling strengthening device and method

Abstract

The invention relates to the technical field of organic synthesis, and provides an ammoxidation coupling strengthening device and method for producing aromatic nitrile and application of the ammoxidation coupling strengthening device and method. The ammoxidation coupling strengthening device and the ammoxidation coupling strengthening method for producing the aromatic nitrile, provided by the invention, can be used for independently producing the phthalonitrile or co-producing the phthalonitrile and the methyl cyanobenzene, and the product composition can be flexibly adjusted according to market requirements; and moreover, the purity of the product is improved, ammonia consumption caused by reaction is reduced, and the utilization rate of raw materials is greatly improved.

Description

Technical Field

[0001] The present invention relates to the technical field of fine chemical intermediate synthesis, and more specifically, to an ammoxidation coupling strengthening device and method for producing aromatic nitriles and their applications. Background Art

[0002] Aromatic nitriles are a type of fine chemical intermediate with very wide applications and can be used to produce chemical products such as pesticides, pharmaceuticals, building materials, insulating materials, oil products, and fuel additives. Among them, isophthalonitrile (IPN) is the most widely used and in the greatest demand variety among aromatic nitriles. It has two main uses. One is that tetrachloroisophthalonitrile (chlorothalonil) obtained by chlorination is a highly efficient and low-toxic fungicide; the other is that m-xylylenediamine obtained by hydrogenation reaction is a resin curing agent with good performance and is also a raw material for polyurethane resin and nylon resin. m-Tolunitrile (MTN) generated during the ammoxidation of m-xylene to produce isophthalonitrile is also an organic compound with wide applications and is mainly used as a pharmaceutical, pesticide, fuel, and organic synthesis intermediate and can be used to synthesize m-toluic acid, etc.

[0003] In the currently disclosed aromatic hydrocarbon ammoxidation technologies, there are very few that involve the production of MTN. In the conventional gas-phase ammoxidation method for producing IPN, there are many side reactions such as ammonia combustion and deep oxidation, which consume a large amount of NH 3 and O 2 in the raw materials, resulting in the reaction ammonia ratio and space ratio required in industrial production being far higher than the stoichiometric ratio, and the effective utilization rate of raw materials and the yield of the target product IPN being low.

[0004] Therefore, it is very meaningful to develop a device and process for preparing m-tolunitrile and to reduce ammonia consumption and increase the yield of isophthalonitrile. Summary of the Invention

[0005] The purpose of the present invention is to provide an ammoxidation coupling strengthening device and method for producing aromatic nitriles to solve the technical problems in the prior art of lacking a device and process for producing m-tolunitrile and the high reaction ammonia ratio and low isophthalonitrile yield during the gas-phase ammoxidation process.

[0006] To achieve the above purpose, the technical solution adopted by the present invention is:

[0007] In the first aspect, the present invention proposes an ammoxidation coupling strengthening device for producing aromatic nitriles, including a feeding unit, a fluidized bed reactor, a separation and product collection unit, and a raw material recycling unit;

[0008] A first gas distributor, a second gas distributor, a third gas distributor, and a circulating cooling pipe are arranged in the fluidized bed reactor;

[0009] The first gas distributor is arranged at the bottom of the fluidized bed reactor, the third gas distributor is arranged above the first gas distributor, and the second gas distributor is arranged between the first gas distributor and the third gas distributor;

[0010] The circulating cooling pipe is used to withdraw reaction heat and control the temperature of the fluidized bed reactor;

[0011] An outlet is arranged at the top of the fluidized bed reactor; a cyclone separator is arranged at the outlet, and the cyclone separator is used for gas-solid separation;

[0012] The feeding unit includes a first feeding pipe and a second feeding pipe for introducing a mixed gas containing oxygen, a third feeding pipe for introducing an organic substance, and a fourth feeding pipe for introducing ammonia; the organic substance includes xylene raw materials and recycled organic substances;

[0013] The first feeding pipe is communicated with the first gas distributor, the second feeding pipe is communicated with the third gas distributor, and the third feeding pipe and the fourth feeding pipe are communicated with the second gas distributor;

[0014] The separation and product collection unit is used to receive the gas-phase stream obtained after gas-solid separation, separate ammonia and recycled organic substances in the gas-phase stream, and collect the target product;

[0015] The raw material recycling unit is used to recycle ammonia and recycled organic substances separated from the gas-phase stream to the feeding unit.

[0016] The device provided by the present invention can be used for producing phthalonitrile or for co-producing phthalonitrile and methylbenzonitrile. When the device is used for producing phthalonitrile, the organic substance fed for the first time through the third feeding pipe can only include xylene raw materials, or can include xylene raw materials and methylbenzonitrile; when the device is used for co-producing phthalonitrile and methylbenzonitrile, the organic substance fed for the first time through the third feeding pipe generally only includes xylene raw materials.

[0017] In the device provided by the present invention, the mixed gas containing oxygen can be introduced into the fluidized bed reactor through two vertically arranged feeding pipelines, namely the first feeding pipe and the second feeding pipe, which can effectively inhibit the occurrence of side reactions and significantly improve the raw material utilization rate and product yield.

[0018] According to some embodiments of the present invention, the xylene raw materials include any one of o-xylene, m-xylene, p-xylene, and 4-nitro-o-xylene.

[0019] According to some embodiments of the present invention, the recycled organic substances include xylene recycled materials and optionally methylbenzonitrile.

[0020] According to some embodiments of the present invention, the target product includes a first target product phthalonitrile and an optional second target product methylbenzonitrile.

[0021] It should be noted that the phthalonitrile in the present invention includes any one of phthalonitrile, isophthalonitrile, terephthalonitrile, 4-nitrophthalonitrile; the methylbenzonitrile includes any one of o-methylbenzonitrile, m-methylbenzonitrile, p-methylbenzonitrile, 4-nitro-o-methylbenzonitrile.

[0022] According to some embodiments of the present invention, the third gas distributor is arranged in the dense phase zone of the reactor.

[0023] According to some embodiments of the present invention, the oxygen-containing mixed gas can be selected from air or a mixture of oxygen and an inert gas.

[0024] According to some embodiments of the present invention, the first gas distributor includes a horizontal distribution plate and a plurality of vertical short tubes perpendicular to the horizontal distribution plate; both ends of the vertical short tube are open, and it is divided into a pressure drop control section and a rectification section from bottom to top;

[0025] The pressure drop control section is in an inverted conical shape with a large top and a small bottom, and the rectification section is a straight tube with a constant inner diameter passing through the horizontal distribution plate; a plurality of air outlet holes are arranged on the side wall of the rectification section above the horizontal distribution plate to form a horizontal air flow to eliminate the catalyst bed dead zones that are likely to form between the vertical short tubes.

[0026] According to some embodiments of the present invention, the length of the pressure drop control section is 0.1 to 0.3 times the length of the rectification section, preferably 0.15 to 0.25 times.

[0027] According to some embodiments of the present invention, the diameter of the bottom opening of the pressure drop control section is 0.1 to 0.5 times the diameter of the top opening, preferably 0.25 to 0.35 times.

[0028] According to some embodiments of the present invention, the inner diameter of the rectification section is the same as the diameter of the top opening of the pressure drop control section.

[0029] According to some embodiments of the present invention, 1 / 20 to 1 / 5 of the rectification section is located above the horizontal distribution plate.

[0030] According to some embodiments of the present invention, the number of the air outlet holes is 3 to 8.

[0031] According to some embodiments of the present invention, a flaring nozzle, such as a horn-shaped nozzle, is arranged on the air outlet hole. The flaring nozzle is beneficial to eliminating the catalyst "dead zones" between the vertical short tubes of the first gas distributor.

[0032] In the present invention, with the first gas distributor adopting the above structure, the fluidization quality of the bed layer can be effectively improved, gas-solid mixing can be promoted, which is conducive to improving the raw material utilization rate and product yield.

[0033] In the present invention, the second gas distributor can adopt a common dendritic tube-type gas distributor.

[0034] According to some embodiments of the present invention, the third gas distributor includes a plurality of annular gas distributors axially distributed along the bed layer of the fluidized bed reactor; the annular gas distributor includes an annular tube and an intake main pipe connected to the annular tube, and a plurality of nozzles are provided on the inner side, lower side or obliquely lower side of the annular tube.

[0035] According to some embodiments of the present invention, the number of the annular gas distributors is 1 to 5.

[0036] According to some embodiments of the present invention, the number of nozzles on the annular tube is 24 to 200.

[0037] According to some embodiments of the present invention, the nozzles are evenly distributed on the annular tube.

[0038] According to some embodiments of the present invention, the nozzles on the annular tube have the same or different sizes.

[0039] According to some embodiments of the present invention, the size of the nozzles gradually decreases in the direction away from the intake main pipe, which can make the flow rates of the nozzles more balanced and is conducive to the progress of the reaction.

[0040] In the present invention, raw material preheaters can be provided at appropriate positions on the first feed pipe, the second feed pipe, the third feed pipe and the fourth feed pipe as the case may be, for preheating various raw materials.

[0041] In the present invention, raw material vaporizers can be provided on the third feed pipe and the fourth feed pipe for vaporizing liquid raw materials.

[0042] According to some embodiments of the present invention, a combined horizontal member is provided between the pipelines of the circulating cooling pipe; the combined horizontal member includes an external structure and an internal structure; the external structure is a hollow frustum with openings at both upper and lower ends, and a plurality of uniformly distributed small holes are opened on the side wall of the hollow frustum; the internal structure is a cross internal member formed by intersecting a plurality of vertically arranged baffles.

[0043] The circulating cooling pipes generally include a number of vertically arranged heat removal water pipes in a fluidized bed reactor. In the present invention, by arranging a combined horizontal member between the pipelines of the circulating cooling pipes (for example, between two adjacent heat removal water pipes), large air bubbles or particle clusters formed in the fluidized bed can be broken, the bed pressure fluctuation can be reduced, and the fluidization quality of the bed can be improved. The specific number of the combined horizontal members is related to the scale of the fluidized bed reactor.

[0044] According to some embodiments of the present invention, the separation and product collection unit includes a product washing tower and a filtering device connected in sequence, and the product washing tower is communicated with the discharge port;

[0045] The product washing tower is used to cool the gas-phase stream obtained after gas-solid separation, and perform gas-liquid separation on the cooled gas-phase stream to obtain a gas component and a liquid-phase stream;

[0046] The filtering device is used to separate the first target product phthalonitrile and the circulating organic matter in the liquid-phase stream.

[0047] In the present invention, the liquid-phase stream is filtered in the filtering device to separate the solid product phthalonitrile and the liquid component including the circulating organic matter.

[0048] According to some embodiments of the present invention, the separation and product collection unit further includes a dehydration device connected to the filtering device and a drying device connected to the dehydration device; the dehydration device and the drying device are respectively used for dehydrating and drying the first target product phthalonitrile.

[0049] According to some embodiments of the present invention, the raw material recycling unit includes an ammonia recycling device and an organic matter recycling device;

[0050] The ammonia recycling device includes an ammonia absorption tower communicated with the product washing tower, and an ammonia recycling pipeline with an inlet communicated with the ammonia absorption tower and an outlet communicated with the fourth feed pipe; the ammonia absorption tower is used to recover ammonia in the gas component and discharge the waste gas in the gas component from the reaction system;

[0051] The organic matter recycling device includes a rectifying tower communicated with the filtering device, and an organic matter recycling pipeline with an inlet communicated with the rectifying tower and an outlet communicated with the third feed pipe; the rectifying tower is used to separate the circulating organic matter.

[0052] In the present invention, the circulating organic matter is separated in the rectifying tower to obtain xylene-like recycled materials, methylbenzonitrile and low-boiling substances, wherein the low-boiling substances are discharged from the top of the rectifying tower, and the methylbenzonitrile can be collected and discharged from the rectifying tower as the second target product, or circulated to the third feed pipe together with the xylene-like recycled materials through the organic matter recycling pipeline.

[0053] In a second aspect, the present invention provides a method for enhancing the ammoxidation coupling for producing aromatic nitriles by using the apparatus described in the first aspect, including: introducing a mixed gas including xylene raw materials, ammonia gas, and oxygen-containing gas into a fluidized bed reactor respectively, and carrying out an ammoxidation reaction under the action of a catalyst; separating ammonia gas and recycling organic matters from the obtained reaction product stream, and collecting the target product; and recycling the ammonia gas and the recycling organic matters separated from the reaction product stream to the feeding unit and introducing them into the fluidized bed reactor to continue the reaction.

[0054] When the target product is the first target product phthalonitrile, the recycling organic matters include recycled xylene materials and methylbenzonitrile.

[0055] When the target products are the first target product phthalonitrile and the second target product methylbenzonitrile, the recycling organic matters include recycled xylene materials.

[0056] According to some embodiments of the present invention, when the target product is the first target product phthalonitrile, the mixed gas initially introduced into the fluidized bed reactor may further include methylbenzonitrile.

[0057] According to some embodiments of the present invention, the oxygen-containing mixed gas is introduced into the fluidized bed reactor through a first feed pipe and a second feed pipe respectively; wherein, the air in the first feed pipe enters the fluidized bed reactor through a first gas distributor, and the air in the second feed pipe enters the fluidized bed reactor through a third gas distributor.

[0058] According to some embodiments of the present invention, the volume ratio of the oxygen-containing mixed gas fed through the first feed pipe and the second feed pipe is (2 - 20):1.

[0059] According to some embodiments of the present invention, the xylene raw materials include any one of o-xylene, m-xylene, p-xylene, and 4-nitro-o-xylene.

[0060] According to some embodiments of the present invention, the molar ratio of the xylene raw materials to the recycling organic matters is 0.5 - 8; preferably 1.5 - 7.5.

[0061] According to some embodiments of the present invention, when the target product is the first target product phthalonitrile:

[0062] The reaction temperature of the ammoxidation reaction is 380 - 500 °C, preferably 390 - 450 °C; the reaction pressure is 0.01 - 0.20 Mpa, preferably 0.02 - 0.10 Mpa.

[0063] The total catalyst load of the ammoxidation reaction is 0.05 - 0.2 h -1 preferably 0.07 - 0.15 h -1 .

[0064] According to some embodiments of the present invention, when the target products are the first target product phthalonitrile and the second target product methylbenzonitrile:

[0065] The reaction temperature of the ammoxidation reaction is 300 - 420 °C, preferably 350 - 415 °C; the reaction pressure is 0.01 - 0.20 Mpa, preferably 0.02 - 0.10 Mpa.

[0066] The total catalyst load of the ammoxidation reaction is 0.08 - 0.3 h -1 , preferably 0.1 - 0.2 h -1 .

[0067] According to some embodiments of the present invention, the catalyst comprises a carrier and an active component; the carrier is silica; the active component comprises a composition containing vanadium and chromium.

[0068] According to some embodiments of the present invention, the carrier content in the catalyst is 30 - 90 wt%.

[0069] According to some embodiments of the present invention, the composition containing vanadium and chromium comprises a composition with the following chemical formula in terms of atomic ratio: V 1.0 Cr a A b B c C d O x ;

[0070] Wherein: A is selected from at least one of boron or phosphorus;

[0071] B is selected from at least one of manganese, nickel, titanium, cobalt, molybdenum, tungsten or rare earth elements;

[0072] C is selected from at least one of lithium, sodium, potassium, rubidium or cesium;

[0073] The value range of a is 0.5 - 2.0;

[0074] The value range of b is 0.2 - 2.0;

[0075] The value range of c is 0.01 - 0.5;

[0076] The value range of d is 0.01 - 0.3;

[0077] x is the number of oxygen atoms required to satisfy the valence of other elements.

[0078] According to some embodiments of the present invention, when the target product is phthalonitrile or phthalonitrile and methylbenzonitrile, the selected catalysts can be the same or different.

[0079] In a third aspect, the present invention provides an application of the device described in the first aspect or the method described in the second aspect in the production of benzonitrile or the co-production of benzonitrile and methylbenzonitrile.

[0080] The beneficial effects of the present invention are at least as follows:

[0081] The ammoxidation coupling strengthening device and method for producing aromatic nitrile provided by the present invention can be used for the sole production of benzonitrile or for the co-production of benzonitrile and methylbenzonitrile, and can flexibly adjust the product composition according to market demand; and is beneficial to improving the product yield and reducing the ammonia consumption caused by the reaction, greatly improving the raw material utilization rate. Description of the Drawings

[0082] Figure 1 It is a schematic flow diagram of the ammoxidation coupling strengthening device for producing aromatic nitrile according to the specific embodiment of the present invention.

[0083] Figure 2 It is a schematic structural diagram of the first gas distributor; wherein, A is a schematic structural diagram of the gas distributor in the prior art, and B, C, and D are schematic structural diagrams of the first gas distributor of the present invention.

[0084] Figure 3 For Figure 2 the nozzle structural diagrams of B, C, and D in

[0085] Figure 4 It is a schematic structural diagram of the third gas distributor.

[0086] Figure 5 It is a schematic structural diagram of the external structure of the combined horizontal member.

[0087] Figure 6 It is a schematic structural diagram of the internal structure of the combined horizontal member.

[0088] Figure 7 It is a schematic diagram of the combination mode of the external structure and the internal structure of the combined horizontal member.

[0089] Wherein, 1-fluidized bed reactor, 2-first gas distributor, 3-second gas distributor, 4-third gas distributor, 5-circulating cooling pipe, 6-combined horizontal member, 7-first raw material preheater, 8-second raw material preheater, 9-third raw material preheater, 10-raw material vaporizer, 11-first feed pipe, 12-second feed pipe, 13-fourth feed pipe, 14-third feed pipe, 15-product washing tower, 16-ammonia absorption tower, 17-non-condensable gas, 18-ammonia circulation pipeline, 19-first target product isophthalonitrile, 20-filtering device, 21-distillation column, 22-organic matter circulation pipeline, 23-second target product m-tolunitrile, 24-low-boiling substances, 25-dehydration device, 26-drying device;

[0090] 201 - Horizontal distribution plate, 202 - Rectifying section, 203 - Bottom opening, 204 - Pressure drop control section, 205 - Part of the rectifying section above the horizontal distribution plate, 206 - Air outlet hole, 207 - Divergent nozzle;

[0091] 401 - Main intake pipe, 402 - Annular pipe, 403 - Nozzle;

[0092] 601 - External structure, 6011 - Hollow frustum, 6012 - Small hole, 602 - Internal structure, 6021 - Support member, 6022 - Baffle, 6023 - Flow guiding hole. Specific implementation manner

[0093] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention clearer and more understandable, the present invention will be further described in detail below in conjunction with specific implementation manners. It should be understood that the specific implementation manners described here are only used to explain this patent in detail and do not limit the protection scope of the present invention in any way.

[0094] Unless otherwise defined, the technical terms used in the following specific implementation manners have the same meanings as commonly understood by those skilled in the art to which the present invention belongs. The reagents used in the following specific implementation manners are all conventional biochemical reagents unless otherwise specified; the raw materials, instruments and equipment, etc. used in the following specific implementation manners can all be obtained through market purchase or can be obtained by existing methods; the reagent dosages, unless otherwise specified, are all reagent dosages in conventional experimental operations; the experimental methods, unless otherwise specified, are all conventional methods.

[0095] A schematic flow diagram of a specific implementation manner of the ammoxidation coupling strengthening device for producing aromatic nitrile provided by the present invention is as Figure 1 shown. The device includes a feeding unit, a fluidized bed reactor 1, a separation and product collection unit, and a raw material recycling unit.

[0096] A first gas distributor 2, a second gas distributor 3, a third gas distributor 4 and a circulating cooling pipe 5 are arranged in the fluidized bed reactor 1. The first gas distributor 2 is arranged at the bottom of the fluidized bed reactor 1, the third gas distributor 4 is arranged above the first gas distributor 2, and the second gas distributor 3 is arranged between the first gas distributor 2 and the third gas distributor 4.

[0097] The structure of the first gas distributor 2 is as Figure 2As shown in the figure, it includes a horizontally distributed plate 201 and a plurality of vertical short tubes perpendicular to the horizontally distributed plate 201; both ends of the vertical short tubes are open, including a pressure drop control section 204 at the lower end and a rectifying section 202 at the upper end. The pressure drop control section 204 is an inverted cone with a larger upper part and a smaller lower part, and the rectifying section 202 is a straight tube with a constant inner diameter passing through the horizontally distributed plate 201; six air outlet holes 206 are arranged on the side wall of the rectifying section 202 above the horizontally distributed plate 201, and a horn-shaped nozzle with a structure as shown in Figure 3 shown in C is arranged on the air outlet hole 206. The length of the pressure drop control section 204 is 0.15 times the length of the rectifying section 202. The diameter of the opening 203 at the bottom of the pressure drop control section 204 is 0.3 times the diameter of the opening at the top. The inner diameter of the rectifying section 202 is the same as the diameter of the opening at the top of the pressure drop control section 204. 1 / 6 of the rectifying section 202 is located above the horizontally distributed plate 201.

[0098] The second gas distributor is a dendritic tube gas distributor.

[0099] The structure of the third gas distributor 4 is as shown in Figure 4 the figure, which includes one annular gas distributor axially distributed along the bed layer of the fluidized bed reactor 1; the annular gas distributor includes an annular tube 402 and an intake main pipe 401 connected to the annular tube 402, and 36 nozzles 403 are evenly arranged on the inner side of the annular tube 402. The size of the nozzle 403 gradually decreases along the direction away from the intake main pipe 401.

[0100] A total of 72 combined horizontal members 6 are arranged between the pipelines of the circulating cooling pipe 5; the structure of the combined horizontal member 6 is as shown in Figures 5-7 the figure, which includes an external structure 601 and an internal structure 602; the external structure 601 is a hollow frustum 6011 with openings at both the upper and lower ends, and a plurality of evenly distributed small holes 6012 are opened on the side wall of the hollow frustum 6011; the internal structure 602 is a cross internal member formed by six vertically arranged baffles 6022 staggered on a support member 6021, and a plurality of diversion holes 6023 are arranged on the baffle 6022.

[0101] An outlet is arranged at the top of the fluidized bed reactor 1; a cyclone separator is arranged at the outlet, and the cyclone separator is used for gas-solid separation.

[0102] The feeding unit includes a first feeding pipe 11 for introducing air, a second feeding pipe 12, a third feeding pipe 14 for introducing organic matter, and a fourth feeding pipe 13 for introducing ammonia. The first feeding pipe 11 is connected to the first gas distributor 2, the second feeding pipe 12 is connected to the third gas distributor 4, and the third feeding pipe 14 and the fourth feeding pipe 13 are connected to the second gas distributor 3.

[0103] A first raw material preheater 7 is provided on the first feed pipe 11 and the second feed pipe 12; a second raw material preheater 8 is provided on the fourth feed pipe 13; the third feed pipe 14 and the fourth feed pipe 13 are respectively connected to the raw material vaporizer 10, and a third raw material preheater 9 is provided on the connecting pipe between the raw material vaporizer 10 and the second gas distributor 3.

[0104] The separation and product collection unit includes a product washing tower 15, a filtering device 20, a dehydration device 25, and a drying device 26 connected in sequence. The product washing tower 15 is connected to the discharge port at the top of the fluidized bed reactor 1.

[0105] The raw material circulation unit includes an ammonia circulation device and an organic matter circulation device; the ammonia circulation device includes an ammonia absorption tower 16 connected to the product washing tower 15, and an ammonia circulation pipeline 18 with an inlet connected to the ammonia absorption tower 16 and an outlet connected to the fourth feed pipe 13; the organic matter circulation device includes a rectification tower 21 connected to the filtering device 20, and an organic matter circulation pipeline 22 with an inlet connected to the rectification tower 21 and an outlet connected to the third feed pipe 14.

[0106] Example 1

[0107] Adopt Figure 1 The ammoxidation coupling strengthening device for producing aromatic nitriles shown is used to co-produce isophthalonitrile and m-tolunitrile.

[0108] After the air is preheated by the first raw material preheater 7, it is divided into two paths. One path is introduced into the fluidized bed reactor 1 through the first feed pipe 11 by the first gas distributor 2 at the bottom of the fluidized bed reactor 1, and the other path is introduced into the fluidized bed reactor 1 through the second feed pipe 12 by the third gas distributor 4. m-Xylene enters the raw material vaporizer 10 through the third feed pipe 14, and ammonia enters the raw material vaporizer 10 through the fourth feed pipe 13 after being preheated by the second raw material preheater 8. After the m-xylene and ammonia gasified by the raw material vaporizer 10 are preheated by the third raw material preheater 9 together, they are then introduced into the fluidized bed reactor 1 by the second gas distributor 3. Air, m-xylene, ammonia and the catalyst (V 1.0 Cr 1.1 B 0.5 P 0.2 Ti 0.1 Mo 0.1 W 0.05 K 0.05 / 60wt% SiO 2)Mixing occurs, and the ammoxidation reaction takes place. After the reaction product stream passes through the cyclone separator at the top of the reactor for gas-solid separation, the obtained solid (mainly the catalyst) returns to the fluidized bed reactor 1, and the gas-phase stream is led out from the discharge port. After being cooled by the product washing tower 15, the obtained gas components enter the ammonia absorption tower 16 for ammonia recovery. The non-condensable gas 17 is led out from the top of the ammonia absorption tower 16 and enters the subsequent waste gas treatment process. The recovered ammonia gas converges with the fourth feed pipe 13 through the ammonia circulation pipeline 18 and enters the fluidized bed reactor 1 again as ammonia raw material to participate in the reaction. The liquid-phase stream obtained after the product washing tower 15 is cooled is filtered through the filtering device 20 to obtain solid components and liquid components. The solid components are dehydrated by the dehydration device 25 and dried by the drying device 26 to obtain the first target product, isophthalonitrile 19; the liquid components are rectified by the rectification tower 21 to separate out low-boiling substances 24, m-tolunitrile, and unreacted m-xylene. Among them, the low-boiling substances 24 are discharged from the top, the second target product, m-tolunitrile 23, is collected, and the unreacted m-xylene converges with the third feed pipe 14 through the organic matter circulation pipeline 22 and enters the reactor again to participate in the reaction.

[0109] Method parameters: Catalyst load 0.12 h -1 , reaction temperature 395 °C, reaction pressure 0.03 Mpa, and the feed molar ratio is m-xylene: ammonia: air = 1:4:16. During the circulation process, the molar ratio of fresh feed m-xylene to recycled organic matter (unreacted m-xylene) is about 1.6:1. The volume ratio of air fed through the first feed pipe 11 and the second feed pipe 12 is 4:1.

[0110] The total reaction conversion rate after 10 cycles is about 94.2%, the isophthalonitrile yield is 33.4%, and the m-tolunitrile yield is 50.2%.

[0111] This example shows that the ammoxidation coupling and strengthening device and method for producing aromatic nitriles provided by the present invention can be used for co-producing isophthalonitrile and m-tolunitrile, preparing m-tolunitrile with a high yield, and the total ammonia ratio in the reaction (the molar ratio of ammonia consumed in the reaction to xylene, 5.6) and the air ratio (the molar ratio of air consumed in the reaction to xylene, 24.3) are relatively low, improving the raw material utilization rate.

[0112] Example 2

[0113] Adopt Figure 1 The ammoxidation coupling and strengthening device for producing aromatic nitriles shown to co-produce isophthalonitrile and m-tolunitrile.

[0114] The production method and process refer to Example 1, with the only difference being that: the reaction temperature is 415°C, the reaction pressure is 0.03 Mpa, and the feed molar ratio is m-xylene: ammonia: air = 1:4:20. The molar ratio of fresh feed m-xylene to recycled organic matter (unreacted m-xylene) is 7.3:1. The volume ratio of air fed through the first feed pipe 11 and the second feed pipe 12 is 4:1.

[0115] The total reaction conversion rate after 10 cycles is approximately 98.7%, the yield of isophthalonitrile is 49.3%, and the yield of m-tolunitrile is 32.5%. The total ammonia ratio of the reaction is 4.1, and the air ratio is 22.4.

[0116] Example 3

[0117] Adopt Figure 1 The ammoxidation coupling strengthening device for producing aromatic nitriles shown in

[0118] The production method and process refer to Example 1, with the difference being that:

[0119] The m-tolunitrile separated by the distillation column 21 and the unreacted m-xylene are combined with the third feed pipe 14 through the organic matter circulation pipeline 22 and enter the reactor again to participate in the reaction.

[0120] The catalyst load is 0.10 h -1 , the reaction temperature is 395°C, the reaction pressure is 0.04 Mpa, and the feed molar ratio is m-xylene: ammonia: air = 1:4:22. The molar ratio of fresh feed m-xylene to recycled organic matter (m-tolunitrile and unreacted m-xylene) is 2.6:1. The volume ratio of air fed through the first feed pipe 11 and the second feed pipe 12 is 5:1.

[0121] The total reaction conversion rate after 10 cycles is approximately 98.8%, the yield of isophthalonitrile is 71.6%, and the yield of m-tolunitrile is 2.5%. The total ammonia ratio of the reaction is 4.5, and the air ratio is 26.7.

[0122] This example illustrates that the ammoxidation coupling strengthening device and method for producing aromatic nitriles provided by the present invention adopt the method of recycling unreacted m-xylene and generated m-tolunitrile, and can prepare isophthalonitrile with a high yield, and the total ammonia ratio of the reaction is significantly decreased compared with Comparative Example 1.

[0123] Example 4

[0124] The production method and process refer to Example 1, with the only difference being that: the structure of the first gas distributor 2 is as shown in Figure 2 A in

[0125] The total conversion rate of the reaction after 10 cycles is approximately 94.0%, the yield of isophthalonitrile is 32.4%, and the yield of m-tolunitrile is 49.3%. The total ammonia ratio of the reaction is 5.8, and the space ratio is 24.7.

[0126] Example 5

[0127] The production method and process refer to Example 1, with the only difference being that the nozzle opening sizes of the third gas distributor 4 are all the same.

[0128] The total conversion rate of the reaction after 10 cycles is approximately 94.3%, the yield of isophthalonitrile is 31.4%, and the yield of m-tolunitrile is 47.7%. The total ammonia ratio of the reaction is 5.7, and the space ratio is 24.3.

[0129] Example 6

[0130] The production method and process refer to Example 1, with the only difference being that no combined horizontal member 6 is provided between the pipelines of the circulating cooling pipe 5.

[0131] The total conversion rate of the reaction after 10 cycles is approximately 93.8%, the yield of isophthalonitrile is 31.2%, and the yield of m-tolunitrile is 46.9%. The total ammonia ratio of the reaction is 5.9, and the space ratio is 25.0.

[0132] Comparative Example 1

[0133] Adopt Figure 1 The ammoxidation coupling strengthening device for producing aromatic nitriles shown in the figure to produce isophthalonitrile.

[0134] The production method and process refer to Example 3, with the difference being that:

[0135] After the reaction product stream passes through the cyclone gas-solid separation at the top of the reactor, the obtained solid (mainly the catalyst) returns to the fluidized bed reactor 1, and the gas-phase stream is led out from the discharge port. After being cooled by the product washing tower 15, the obtained gas components enter the ammonia absorption tower 16 for ammonia recovery. The non-condensable gas 17 is led out from the top of the ammonia absorption tower 16 and enters the subsequent waste gas treatment process. The recovered ammonia gas converges with the fourth feed pipe 13 through the ammonia circulation pipeline and enters the fluidized bed reactor 1 again as ammonia raw material to participate in the reaction. The liquid-phase stream obtained after cooling by the product washing tower 15 is filtered through the filtering device 20, and the solid components are collected. After the solid components are dehydrated by the dehydration device 25 and dried by the drying device 26, the first target product isophthalonitrile 19 is obtained.

[0136] Catalyst loading 0.08h -1 , the reaction temperature is 415°C, the reaction pressure is 0.02 Mpa, and the feed molar ratio is m-xylene: ammonia: air = 1:7:36.

[0137] The conversion rate of m-xylene is 98.8%, the yield of isophthalonitrile is 71.8%, and the yield of m-tolunitrile is 5.6%. Compared with Example 3, the ammonia ratio required for the reaction in this comparative example is higher (5.6), and the space ratio is higher (36).

[0138] Comparative Example 2

[0139] Use Figure 1 The ammoxidation coupling strengthening device for producing aromatic nitriles shown in the figure to produce isophthalonitrile.

[0140] The production method and process refer to Example 3, the difference is that: after the air is preheated by the first raw material preheater 7, all of it is introduced into the fluidized bed reactor 1 through the first feed pipe 11 by the first gas distributor 2 at the bottom of the fluidized bed reactor 1.

[0141] The total conversion rate of the reaction after 10 cycles is about 98.5%, the yield of isophthalonitrile is 70.9%, and the yield of m-tolunitrile is 2.5%. The total ammonia ratio of the reaction is 4.7, and the space ratio is 27.2.

[0142] Comparative Example 3

[0143] Use Figure 1 The ammoxidation coupling strengthening device for producing aromatic nitriles shown in the figure co-produces isophthalonitrile and m-tolunitrile.

[0144] The production method and process refer to Example 1, the only difference is that: after the air is preheated by the first raw material preheater 7, all of it is introduced into the fluidized bed reactor 1 through the first feed pipe 11 by the first gas distributor 2 at the bottom of the fluidized bed reactor 1.

[0145] The total conversion rate of the reaction after 10 cycles is about 94.0%, the yield of isophthalonitrile is 31.6%, and the yield of m-tolunitrile is 47.8%. The total ammonia ratio of the reaction is 5.8, and the space ratio is 25.5.

[0146] Comparative Example 4

[0147] Use Figure 1 The ammoxidation coupling strengthening device for producing aromatic nitriles shown in the figure co-produces isophthalonitrile and m-tolunitrile.

[0148] The production method and process refer to Example 1, the only difference is that: after the air is preheated by the first raw material preheater 7, all of it is introduced into the fluidized bed reactor 1 through the second feed pipe 12 by the third gas distributor 4.

[0149] The total conversion rate of the reaction after 10 cycles is about 92.2%, the yield of isophthalonitrile is 28.2%, and the yield of m-tolunitrile is 33.3%. The total ammonia ratio of the reaction is 6.3, and the space ratio is 27.5.

[0150] It should be noted that the above-described embodiments are only used to explain the present invention and do not constitute any limitation to the present invention. The present invention has been described by referring to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory words rather than limiting words. Modifications can be made to the present invention within the scope of the claims of the present invention as stipulated, and the present invention can be revised without departing from the scope and spirit of the present invention. Although the present invention described therein relates to specific methods, materials and embodiments, it does not mean that the present invention is limited to the specific examples disclosed therein. On the contrary, the present invention can be extended to all other methods and applications with the same functions.

Claims

1. An ammonia oxidation coupling enhancement device for producing aromatic nitrile, characterized in that: It includes a feeding unit, a fluidized bed reactor (1), a separation and product collection unit, and a raw material circulation unit; The fluidized bed reactor (1) is provided with a first gas distributor (2), a second gas distributor (3), a third gas distributor (4) and a circulating cooling pipe (5); The first gas distributor (2) is arranged at the bottom of the fluidized bed reactor (1), the third gas distributor (4) is arranged above the first gas distributor (2), and the second gas distributor (3) is arranged between the first gas distributor (2) and the third gas distributor (4); The circulating cooling pipe (5) is used to remove reaction heat and regulate the temperature of the fluidized bed reactor (1); The fluidized bed reactor (1) is provided with a discharge port at the top; the discharge port is provided with a cyclone separator, and the cyclone separator is used for gas-solid separation; The feed unit comprises a first feed pipe (11) and a second feed pipe (12) for introducing a mixed gas containing oxygen, a third feed pipe (14) for introducing organic matter, and a fourth feed pipe (13) for introducing ammonia; the organic matter comprises xylene raw materials and recycled organic matter; The first feed pipe (11) is connected to the first gas distributor (2), the second feed pipe (12) is connected to the third gas distributor (4), and the third feed pipe (14) and the fourth feed pipe (13) are connected to the second gas distributor (3); The separation and product collection unit is used to receive the gas phase stream obtained after gas-solid separation, separate ammonia and circulating organic matter in the gas phase stream, and collect the target product; The raw material circulation unit is used to circulate the ammonia and circulating organic matter separated from the gas phase flow to the feed unit.

2. The device according to claim 1, characterized in that The first gas distributor (2) comprises a horizontal distribution plate (201) and a plurality of vertical short tubes perpendicular to the horizontal distribution plate (201); both ends of the vertical short tubes are open and are divided from bottom to top into a pressure drop control section (204) and a rectifying section (202); The pressure drop control section (204) is in the shape of an inverted cone with a larger top and a smaller bottom; the rectifying section (202) is a straight pipe with a constant inner diameter and passing through the horizontal distribution plate (201); a plurality of air outlet holes (206) are arranged on the side wall of the rectifying section (202) located above the horizontal distribution plate (201); Preferably, and / or, the length of the pressure drop control section (204) is 0.1 to 0.3 times, preferably 0.15 to 0.25 times, the length of the rectifying section (202); and / or, the diameter of the bottom opening (203) of the pressure drop control section (204) is 0.1 to 0.5 times, preferably 0.25 to 0.35 times, the diameter of the top opening; And / or, the inner diameter of the rectifying section (202) is the same as the diameter of the top opening of the pressure drop control section (204); and / or, 1 / 20 to 1 / 5 of the rectifying section (202) is located above the horizontal distribution plate (201); And / or, the number of the air outlet holes (206) is 3 to 8; And / or, a gradually widening nozzle (207) is provided on the air outlet (206).

3. The device according to claim 1 or 2, characterized in that: The third gas distributor (4) comprises a plurality of annular gas distributors distributed along the axial direction of the bed layer of the fluidized bed reactor (1); the annular gas distributor comprises an annular pipe (402) and an air inlet main pipe (401) connected to the annular pipe (402); a plurality of nozzles (403) are arranged on the inner side, lower side or oblique lower side of the annular pipe (402); Preferably, The number of the annular gas distributors is 1 to 5; and / or, the nozzles (403) are evenly distributed on the annular tube (402); And / or, the sizes of the nozzles (403) on the annular tube (402) are the same or different; preferably, the size of the nozzles (403) gradually decreases in a direction away from the air intake main tube (401).

4. The device according to any one of claims 1 to 3, characterized in that A combined horizontal component (6) is arranged between the pipelines of the circulating cooling pipe (5); the combined horizontal component (6) includes an external structure (601) and an internal structure (602); the external structure (601) is a hollow frustum body (6011) with openings at both ends, and a plurality of small holes (6012) are provided on the side wall of the hollow frustum body (6011); the internal structure (602) is a cross internal component formed by staggeredly interlacing a plurality of vertically arranged baffles (6022), and a plurality of guide holes (6023) are provided on the baffles (6022).

5. The device according to any one of claims 1 to 4, characterized in that The separation and product collection unit comprises a product washing tower (15) and a filtering device (20) connected in sequence, wherein the product washing tower (15) is connected to the discharge port; The product washing tower (15) is used to cool the gas phase stream obtained after gas-solid separation, and to perform gas-liquid separation on the cooled gas phase stream to obtain gas components and liquid phase stream; The filtering device (20) is used to separate the first target product phthalonitrile and the circulating organic matter in the liquid phase flow; Preferably, the separation and product collection unit further comprises a dehydration device (25) connected to the filtering device (20) and a drying device (26) connected to the dehydration device (25); the dehydration device (25) and the drying device (26) are used to dehydrate and dry the first target product, phthalonitrile, respectively.

6. The device according to claim 5, characterized in that The raw material circulation unit includes an ammonia circulation device and an organic matter circulation device; The ammonia circulation device comprises an ammonia absorption tower (16) connected to the product washing tower (15), and an ammonia circulation pipeline (18) whose inlet is connected to the ammonia absorption tower (16) and whose outlet is connected to the fourth feed pipe (13); the ammonia absorption tower (16) is used to recover ammonia in the gas component and discharge the waste gas in the gas component out of the reaction system; The organic matter circulation device comprises a distillation tower (21) connected to the filtering device (20), and an organic matter circulation pipeline (22) whose inlet is connected to the distillation tower (21) and whose outlet is connected to the third feed pipe (14); the distillation tower (21) is used to separate and circulate organic matter.

7. A method for enhancing the ammoxidation coupling of aromatic nitrile by using the device according to any one of claims 1 to 6, characterized in that: include: A xylene raw material, ammonia, and a mixed gas containing oxygen are introduced into a fluidized bed reactor (1) to cause an ammonia oxidation reaction under the action of a catalyst; The obtained reaction product stream is subjected to ammonia separation and circulating organic matter separation to collect the target product; and the ammonia and circulating organic matter separated from the reaction product stream are recycled to the feed unit and introduced into the fluidized bed reactor (1) to continue the reaction; When the target product is the first target product phthalonitrile, the circulating organic matter includes xylene recovery material and methylbenzonitrile; When the target products are the first target product phthalonitrile and the second target product methylbenzonitrile, the circulating organic matter includes xylene recovery material.

8. The method according to claim 7, characterized in that The oxygen-containing mixed gas is introduced into the fluidized bed reactor (1) through the first feed pipe (11) and the second feed pipe (12) respectively; preferably, the volume ratio of the oxygen-containing mixed gas fed through the first feed pipe (11) and the second feed pipe (12) is (2-20):1; And / or, the xylene raw material includes any one of o-xylene, m-xylene, p-xylene and 4-nitro o-xylene; And / or, the molar ratio of the xylene raw material to the circulating organic matter is 0.5 to 8; preferably 1.5 to 7.

5.

9. The method according to claim 7 or 8, characterized in that: When the target product is the first target product phthalonitrile, The reaction temperature of the ammoxidation reaction is 380-500°C, preferably 390-450°C; the reaction pressure is 0.01-0.20Mpa, preferably 0.02-0.10Mpa; And / or, the total catalyst load of the ammoxidation reaction is 0.05 to 0.2 h -1 , preferably 0.07~0.15h -1 ; When the target product is the first target product phthalonitrile and the second target product methylbenzonitrile, The reaction temperature of the ammoxidation reaction is 300-420°C, preferably 350-415°C; the reaction pressure is 0.01-0.20Mpa, preferably 0.02-0.10Mpa; And / or, the total catalyst load of the ammoxidation reaction is 0.08 to 0.3 h -1 , preferably 0.1 to 0.2h -1 .

10. Use of the device according to any one of claims 1 to 6 or the method according to any one of claims 7 to 9 in the production of phthalonitrile or the co-production of phthalonitrile and methylbenzonitrile.

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