CN111111562B

CN111111562B - Aromatic ammoxidation combined fluidized bed reaction device and reaction method thereof

Info

Publication number: CN111111562B
Application number: CN201811275233.7A
Authority: CN
Inventors: 杨为民; 徐俊; 钟思青; 顾龙勤
Original assignee: China Petroleum and Chemical Corp; Sinopec Shanghai Research Institute of Petrochemical Technology
Current assignee: China Petroleum and Chemical Corp; Sinopec Shanghai Research Institute of Petrochemical Technology
Priority date: 2018-10-30
Filing date: 2018-10-30
Publication date: 2022-08-12
Anticipated expiration: 2038-10-30
Also published as: CN111111562A

Abstract

The invention relates to an aromatic ammoxidation combined fluidized bed reaction device and a reaction method thereof, and mainly solves the problems that the adjustment heat range in a reactor of the existing device is small, a heat collector cannot be repaired and kept in production on line after being worn, the ammonia ratio is large, the air ratio is large, and the utilization rate of raw materials is low. The invention relates to a combined fluidized bed reaction device for aromatic ammoxidation and a reaction method thereof, wherein aromatic hydrocarbon/ammonia is vaporized and enters a reactor with air from an air distribution chamber, then the aromatic ammoxidation reaction is carried out under the action of a catalyst, the heat released in the reaction process is brought into an oxygen supply heat exchanger through the catalyst, the high-efficiency heat exchange is carried out under the action of a forced mixing component, the lattice oxygen supplement treatment of the catalyst is carried out simultaneously, and then the catalyst with low temperature and high lattice oxygen is recycled and returned to the reactor to continuously participate in the aromatic ammoxidation reaction. Can be used in the production of aromatic nitrile by ammoxidation of aromatic hydrocarbon.

Description

Aromatic ammoxidation combined fluidized bed reaction device and reaction method thereof

Technical Field

The invention relates to an aromatic ammoxidation combined fluidized bed reaction device and a reaction method thereof.

Background

The aromatic nitrile is a substance directly connected by a cyano group and an aromatic ring, the cyano group connected with the aromatic ring has high reaction activity, can be used for preparing various fine chemical products through reactions such as hydrolysis, addition, polymerization, hydrogenation, halogenation and the like, is widely applied to the fields of pesticides, medicines, dyes, food additives, high molecular monomers and the like, and is an important fine chemical intermediate.

There are many methods for producing aromatic nitrile, but the simplest, effective and most economical method is to adopt corresponding aromatic hydrocarbon, ammonia and air to carry out direct ammoxidation reaction to obtain the aromatic nitrile product. The reaction of an aromatic hydrocarbon or substituted aromatic hydrocarbon with ammonia and oxygen in the gas phase is referred to as the gas phase ammoxidation of the aromatic hydrocarbon. The reaction of the vapor phase ammoxidation mainly comprises fixed bed and fluidized bed processes. The gas phase ammoxidation reaction of aromatic hydrocarbon is a strong exothermic reaction, and a large amount of reaction heat can be generated in the reaction process, so that the fluidized bed reactor is a better solution method.

JP10120641 discloses a fluidized bed process for producing aromatic nitrile, which adopts a multi-component catalyst taking V/Mo as a main component, oxygen and raw materials are fed in a segmented mode, and catalysts with different compositions are respectively filled in a segmented air inlet to produce 2, 6-dichlorobenzonitrile and benzonitrile products; US6429330, JP2001348370 disclose a method for producing isophthalonitrile and 3-cyanopyridine using a fluidized bed, using a fluidized bed vapor phase ammoxidation process, a multicomponent catalyst having V/Mo/Fe as a main component, wherein unreacted ammonia gas is recycled by an absorber regenerator; US5747411 also discloses a method for producing phthalonitrile using a fluidized bed, in which a multi-component catalyst having V/Sb as a main component is impregnated with a carrier, and CN204429253U discloses a two-stage distribution apparatus of an ammoxidation fluidized bed, in which a second distribution plate is disposed 3.6m above a first distribution plate, so that the process of refining isophthalonitrile alone can be reduced, the production process can be optimized, and the production cost can be reduced.

The above patents all adopt a fluidized bed reaction form to produce the aromatic nitrile by ammoxidation, and adopt a V-containing multi-component catalyst to obtain higher product yield, but more excessive ammonia and air reduce the economical efficiency of the production process, increase the pressure of ammonia recovery and three-waste treatment thereof, increase the production energy consumption and influence the stability of the catalyst. The invention can adjust the heat range in the reactor according to different working conditions by optimizing the structure of the reactor and improving the reaction process conditions, is convenient for maintaining the heat exchanger, and simultaneously reduces the ammonia ratio and the air ratio of the reaction, thereby effectively reducing the production cost.

Disclosure of Invention

The invention aims to solve the technical problems that in the prior art, the range of heat regulation in a reactor is small, a heat collector cannot be maintained in production through online rush repair after being worn, the ammonia ratio is large, the air ratio is large, raw materials are not fully utilized, the ammonia content in wastewater is high, and a large amount of nitrogen is generated in the reaction process, so that the economy of the production process is reduced.

The second technical problem to be solved by the present invention is to provide a reaction method corresponding to the first technical problem.

In order to solve one of the above technical problems, the technical scheme adopted by the invention is as follows: a combined fluidized bed reactor for ammoxidation of aromatic hydrocarbon comprises a fluidized bed reactor 1, a gas distribution chamber 4, a circulating feed pipe 9, an oxygen supply heat exchanger 10 and a circulating return pipe 13; the fluidized bed reactor 1 comprises a reactor dense-phase zone 3 and a reactor dilute-phase zone 2; at least one group of intensive mixing components 11 are arranged in the oxygen supply heat exchanger 10. The upper end of the reactor dense-phase zone 3 of the fluidized bed reactor 1 is communicated with an oxygen supply heat exchanger 10 through a circulating feeding pipe 9; the lower end of the reactor dense-phase zone 3 of the fluidized bed reactor 1 is communicated with an oxygen supply heat exchanger 10 through a circulating return pipe 13; the fluidized bed reactor 1 is communicated with the gas distribution chamber 4; the side surface of the upper end of the cyclone separator 7 is communicated with the dilute phase zone 2 of the reactor; the bottom is communicated with the dense phase zone 3 of the reactor through a cyclone dipleg 6.

In the technical scheme, the ratio of the cross section of the oxygen supply heat exchanger 10 to the cross section area of the fluidized bed reactor 1 is not more than 0.5. The intensive mixing component 11 is formed by combining a component upper baffle 21 and a component lower baffle 22; the component upper baffle 21 and the component lower baffle 22 are respectively formed by combining two blades in a V shape and an inverted V shape; the included angle alpha of the two blades of the upper baffle of the component is not smaller than the included angle beta of the two blades of the lower baffle of the component. The two blades of the upper baffle plate 21 of the intensive mixing component 11 are provided with openings and/or slits, and the opening rate of the ratio of the total area of the openings and/or slits to the area of the blades is 3-15%. The two blades of the lower baffle 22 of the intensive mixing component 11 are provided with openings and/or slits, and the opening ratio of the total area of the openings and/or slits to the area of the blades is 1-10%. The intensive mixing members 11 are uniformly distributed in the reactor in a staggered mode, and the acute/right angle of pairwise intersection between every two adjacent intensive mixing members 11 in the vertical direction is 30-90 degrees. The intensive mixing members 11 are parallel to each other on the same cross section, and the vertical distance between the adjacent intensive mixing members 11 in the horizontal direction is not less than 100 mm.

In order to solve the second problem, the technical scheme adopted by the invention is that the aromatic ammoxidation combined fluidized bed reaction method adopts the aromatic ammoxidation combined fluidized bed reaction device, and comprises the following steps:

a. after being vaporized, the aromatic hydrocarbon/ammonia and air enter a dense-phase zone 3 of a reactor of a fluidized bed reactor 1 from an air distribution chamber 4, and then carry out ammoxidation reaction of the aromatic hydrocarbon under the action of a catalyst;

b. after leaving the dense-phase zone 3 of the reactor, the aromatic nitrile effluent 8 and a small part of catalyst generated by the reaction enter the dilute-phase zone 2 of the reactor, after being separated by a cyclone separator 7, the aromatic nitrile effluent 8 flows out of the fluidized bed reactor 1 and is received by methods such as condensation or solvent absorption, and is refined by methods such as rectification or recrystallization to obtain product gas, and the catalyst flows into the dense-phase zone 3 of the reactor through a cyclone dipleg 6 after being separated;

c. after leaving the fluidized bed reactor 1, a part of the catalyst in the dense-phase zone 3 of the reactor flows into an oxygen supply heat exchanger 10 through a circulating feeding pipe 9, is fully mixed and contacted with air under the action of a strong mixing component, performs high-efficiency heat exchange, simultaneously performs catalyst lattice oxygen supplement treatment, and then returns to the fluidized bed reactor 1 through a circulating return pipe 13 to continuously participate in aromatic ammoxidation.

In the technical scheme, in the dense-phase zone 3 of the reactor, the reaction raw materials are aromatic hydrocarbons and derivatives thereof of C7-C8, ammonia gas and air, and the molar ratio is 1: (1-10): (10-40), the reaction temperature is 350-480 ℃, the pressure is 0.01-0.11 MPa, and the gas apparent linear speed is 0.2-0.8 m/s; the surface line-observing speed of the gas in the oxygen supply heat exchanger 10 is 0.05-0.4 m/s.

The method adopts a reactor internally provided with a plurality of groups of strong mixing components to simultaneously carry out lattice oxygen supplement and heat exchange, realizes optimization of process conditions, improves heat exchange efficiency under the condition of ensuring reduction of total ammonia ratio and air ratio, can flexibly adjust heat in the reactor, is convenient for maintenance and overhaul of a heat exchanger, obtains higher product yield, improves the utilization rate of raw materials, and achieves the purposes of energy conservation, consumption reduction and emission reduction.

The invention adopts a reactor, namely an oxygen supply heat exchanger 10, which is internally provided with a plurality of groups of intensive mixing components 11 to finely control the proceeding of heat exchange and oxygen supply, and optimizes the proceeding of the reaction from a finer scale. By combining the circulation and the coupling of the fluidized bed reactor 1 and the oxygen supply heat exchanger 10, on one hand, the heat balance of the system can be efficiently and stably maintained, thereby improving the product distribution, improving the yield of the target product and prolonging the long-period operation time; in addition, excessive supply of other raw materials such as oxygen, ammonia and the like in the prior art can be effectively avoided, and economic benefits can be greatly improved.

The intensive mixing component 11 arranged in the oxygen supply heat exchanger 10 in the technology can strengthen the flowing and mixing in the oxygen supply heat exchanger 10, and compared with the prior art, the heat transfer efficiency is greatly improved; on the other hand, the arrangement of the strong mixing component 11 is beneficial to inhibiting the growth of bubbles in the reactor, effectively improves the fluidization quality and further improves the running speed of the whole system. The intensive mixing component 11 can also be arranged in the fluidized bed reactor 1 to break the bubbles in the reactor and improve the mass transfer and fluidization quality of the catalyst particles in the fluidized bed reactor 1.

Compared with the prior art, the method for producing the benzonitrile, the o-chlorobenzonitrile, the m-phthalonitrile, the 3-cyanopyridine and the like has the advantages that the reaction and oxygen supply are refined in two areas, the fluidization quality and the heat exchange level of the fluidized bed are improved under the condition that the local ammonia ratio and the air ratio meet the process requirements, the total ammonia ratio and the total air ratio are effectively reduced, the utilization rate of raw materials is improved, the purposes of saving energy, reducing consumption and reducing emission are achieved, the product yield is improved, and good technical effects are obtained.

Drawings

FIG. 1 is a schematic diagram of a combined fluidized bed reactor for ammoxidation of aromatic hydrocarbons and a reaction method thereof according to the present invention;

FIG. 2 is a schematic diagram of an oxygen supply heat exchanger according to the present invention;

FIG. 3 is a partial schematic view of an intensive mixing element according to the present invention;

in FIG. 1, 1 is a fluidized bed reactor; 2 is a reactor dilute phase zone; 3 is a dense-phase zone of the reactor; 4 is an air distribution chamber; 5 is a reaction raw material; 6 is a cyclone dipleg; 7 is a cyclone separator; 8 is an aromatic nitrile effluent; 9 is a circulating feeding pipe; 10 is an oxygen supply heat exchanger; 11 is a strong mixing component; 12 is oxygen supply fluidization feeding; and 13 is a circulating return pipe.

In fig. 2, 10 is an oxygen supply heat exchanger; 11 is a strong mixing component; 12 is an oxygen-supplying fluidized feed.

In fig. 3, 20 is a cross section of the intensive mixing member; 21 is a component upper baffle plate; 22 is a component lower baffle plate; alpha is the included angle of two blades of the baffle on the component; beta is the included angle of two blades of the lower baffle plate of the component.

The invention is further illustrated by the following examples.

Detailed Description

The present invention will be further illustrated by the following examples, but is not limited to these examples.

[ example 1 ]

After being vaporized, toluene and ammonia and air enter a dense-phase region of a reactor of a fluidized bed reactor from a gas distribution chamber, and then carry out aromatic ammoxidation reaction under the action of a catalyst; after the corresponding cyanobenzene generated by the reaction and a small part of catalyst leave a dense-phase zone of the reactor, the cyanobenzene enters a dilute-phase zone of the reactor, after the cyanobenzene is separated by a cyclone separator, the cyanobenzene flows out of a fluidized bed reactor and is received by methods such as condensation or solvent absorption, and is refined by methods such as rectification or recrystallization to obtain product gas, and the catalyst flows into the dense-phase zone of the reactor through a cyclone dipleg after being separated; after a part of catalyst in the dense-phase zone of the reactor leaves the fluidized bed reactor, the catalyst flows into the oxygen supply heat exchanger through the circulating feeding pipe and is fully mixed and contacted with air under the action of the strong mixing component to perform high-efficiency heat exchange, and meanwhile, the catalyst lattice oxygen is supplemented, and then the catalyst returns to the fluidized bed reactor through the circulating return pipe to continuously participate in the reaction.

In the experiment, the included angle alpha of the two blades of the upper baffle plate of the component is 60 degrees, and the included angle beta of the two blades of the lower baffle plate of the component is 60 degrees. The two blades of the baffle plate on the component of the intensive mixing component are provided with openings and/or slits, and the ratio of the total area of the openings and/or slits to the area of the blades has the opening rate of 5%. The two blades of the lower baffle of the intensive mixing component are provided with openings and/or slits, and the ratio of the total area of the openings and/or slits to the area of the blades has the opening rate of 3%. The intensive mixing components are uniformly distributed in the reactor in a staggered mode, and the acute/right angle of pairwise intersection between every two adjacent intensive mixing components in the vertical direction is 60 degrees.

The reaction raw materials in the dense-phase zone of the fluidized bed reactor are toluene, ammonia gas and air, and the molar ratio is 1: 3: 15, the reaction temperature is 400 ℃, and the gas apparent linear velocity is 0.5 m/s. The superficial linear velocity of the gas in the oxygen supply heat exchanger was 0.2m/s, the yield of benzonitrile was 82.9%, and the results are detailed in Table 1.

[ example 2 ]

In the experiment, the included angle alpha of the two blades of the upper baffle plate of the component is 90 degrees, and the included angle beta of the two blades of the lower baffle plate of the component is 60 degrees. The two blades of the baffle plate on the component of the intensive mixing component are provided with openings and/or slits, and the ratio of the total area of the openings and/or slits to the area of the blades has the opening rate of 5%. The two blades of the lower baffle of the intensive mixing component are provided with openings and/or slits, and the ratio of the total area of the openings and/or slits to the area of the blades has the opening rate of 3%. The intensive mixing components are uniformly distributed in the reactor in a staggered mode, and the acute/right angle of pairwise intersection between every two adjacent intensive mixing components in the vertical direction is 60 degrees.

The reaction raw materials in the dense-phase zone of the fluidized bed reactor are toluene, ammonia gas and air, and the molar ratio is 1: 3: 15, the reaction temperature is 400 ℃, and the gas apparent linear velocity is 0.5 m/s. The superficial gas velocity in the oxygen supply heat exchanger was 0.2m/s, the yield of benzonitrile was 82.7%, and the results are detailed in Table 1.

[ example 3 ]

After being vaporized, toluene and ammonia and air enter a dense-phase region of a reactor of a fluidized bed reactor from a gas distribution chamber, and then carry out aromatic ammoxidation reaction under the action of a catalyst; after the corresponding cyanobenzene generated by the reaction and a small part of catalyst leave a dense-phase zone of the reactor, the cyanobenzene enters a dilute-phase zone of the reactor, after the cyanobenzene is separated by a cyclone separator, the cyanobenzene flows out of a fluidized bed reactor and is received by methods such as condensation or solvent absorption, and is refined by methods such as rectification or recrystallization to obtain product gas, and the catalyst flows into the dense-phase zone of the reactor through a cyclone dipleg after being separated; after leaving the fluidized bed reactor, part of the catalyst in the dense phase zone of the reactor flows into an oxygen supply heat exchanger through a circulating feeding pipe, is fully mixed and contacted with air under the action of a strong mixing component, carries out high-efficiency heat exchange, simultaneously carries out catalyst lattice oxygen supplement treatment, and then returns to the fluidized bed reactor through a circulating return pipe to continuously participate in the reaction.

In the experiment, the included angle alpha of the two blades of the upper baffle plate of the component is 60 degrees, and the included angle beta of the two blades of the lower baffle plate of the component is 120 degrees. The two blades of the baffle plate on the component of the intensive mixing component are provided with openings and/or slits, and the ratio of the total area of the openings and/or slits to the area of the blades has the opening rate of 5%. The two blades of the lower baffle of the intensive mixing component are provided with openings and/or slits, and the ratio of the total area of the openings and/or slits to the area of the blades has an opening rate of 3%. The intensive mixing components are uniformly distributed in the reactor in a staggered mode, and the acute/right angle of pairwise intersection between every two adjacent intensive mixing components in the vertical direction is 60 degrees.

The reaction raw materials in the dense-phase zone of the fluidized bed reactor are toluene, ammonia gas and air, and the molar ratio is 1: 3: 15, the reaction temperature is 400 ℃, and the gas apparent linear velocity is 0.5 m/s. The superficial linear velocity of the gas in the oxygen supply heat exchanger was 0.2m/s, the yield of benzonitrile was 82.6%, and the results are detailed in Table 1.

[ example 4 ]

In the experiment, the included angle alpha of the two blades of the upper baffle plate of the component is 60 degrees, and the included angle beta of the two blades of the lower baffle plate of the component is 60 degrees. The two blades of the baffle plate on the component of the intensive mixing component are provided with openings and/or slits, and the ratio of the total area of the openings and/or slits to the area of the blades has the opening rate of 3%. The two blades of the lower baffle of the intensive mixing component are provided with openings and/or slits, and the ratio of the total area of the openings and/or slits to the area of the blades has the opening rate of 3%. The intensive mixing components are uniformly distributed in the reactor in a staggered mode, and the acute/right angle of pairwise intersection between every two adjacent intensive mixing components in the vertical direction is 60 degrees.

[ example 5 ]

In the experiment, the included angle alpha of the two blades of the upper baffle plate of the component is 60 degrees, and the included angle beta of the two blades of the lower baffle plate of the component is 60 degrees. The two blades of the baffle plate on the component of the intensive mixing component are provided with openings and/or slits, and the ratio of the total area of the openings and/or slits to the area of the blades has an opening rate of 15%. The two blades of the lower baffle of the intensive mixing component are provided with openings and/or slits, and the ratio of the total area of the openings and/or slits to the area of the blades has the opening rate of 3%. The intensive mixing components are uniformly distributed in the reactor in a staggered mode, and the acute/right angle of pairwise intersection between every two adjacent intensive mixing components in the vertical direction is 60 degrees.

The reaction raw materials in the dense-phase zone of the fluidized bed reactor are toluene, ammonia gas and air, and the molar ratio is 1: 3: 15, the reaction temperature is 400 ℃, and the gas apparent linear velocity is 0.5 m/s. The superficial linear velocity of the gas in the oxygen supply heat exchanger was 0.2m/s, the yield of benzonitrile was 82.2%, and the results are detailed in Table 1.

[ example 6 ]

In the experiment, the included angle alpha of the two blades of the upper baffle plate of the component is 60 degrees, and the included angle beta of the two blades of the lower baffle plate of the component is 60 degrees. The two blades of the baffle plate on the component of the intensive mixing component are provided with openings and/or slits, and the ratio of the total area of the openings and/or slits to the area of the blades has the opening rate of 5%. The two blades of the lower baffle of the intensive mixing component are provided with openings and/or slits, and the ratio of the total area of the openings and/or slits to the area of the blades has an opening rate of 1%. The intensive mixing components are uniformly distributed in the reactor in a staggered mode, and the acute/right angle of pairwise intersection between every two adjacent intensive mixing components in the vertical direction is 60 degrees.

The reaction raw materials in the dense-phase zone of the fluidized bed reactor are toluene, ammonia gas and air, and the molar ratio is 1: 3: 15, the reaction temperature is 400 ℃, and the gas apparent linear velocity is 0.5 m/s. The superficial linear velocity of the gas in the oxygen supply heat exchanger was 0.2m/s, the yield of benzonitrile was 82.4%, and the results are detailed in Table 2.

[ example 7 ]

In the experiment, the included angle alpha of the two blades of the upper baffle plate of the component is 60 degrees, and the included angle beta of the two blades of the lower baffle plate of the component is 60 degrees. The two blades of the baffle plate on the component of the intensive mixing component are provided with openings and/or slits, and the ratio of the total area of the openings and/or slits to the area of the blades has the opening rate of 5%. The two blades of the lower baffle of the intensive mixing component are provided with openings and/or slits, and the ratio of the total area of the openings and/or slits to the area of the blades has an opening rate of 10%. The intensive mixing components are uniformly distributed in the reactor in a staggered mode, and the acute/right angle of pairwise intersection between every two adjacent intensive mixing components in the vertical direction is 60 degrees.

The reaction raw materials in the dense-phase zone of the fluidized bed reactor are toluene, ammonia gas and air, and the molar ratio is 1: 3: 15, the reaction temperature is 400 ℃, and the gas apparent linear velocity is 0.5 m/s. The superficial linear velocity of the gas in the oxygen supply heat exchanger was 0.2m/s, the yield of benzonitrile was 82.3%, and the results are detailed in Table 2.

[ example 8 ]

In the experiment, the included angle alpha of the two blades of the upper baffle plate of the component is 60 degrees, and the included angle beta of the two blades of the lower baffle plate of the component is 60 degrees. The two blades of the baffle plate on the component of the intensive mixing component are provided with openings and/or slits, and the ratio of the total area of the openings and/or slits to the area of the blades has the opening rate of 5%. The two blades of the lower baffle of the intensive mixing component are provided with openings and/or slits, and the ratio of the total area of the openings and/or slits to the area of the blades has the opening rate of 3%. The intensive mixing components are uniformly distributed in the reactor in a staggered mode, and the acute/right angle of pairwise intersection between every two adjacent intensive mixing components in the vertical direction is 30 degrees.

The reaction raw materials in the dense-phase zone of the fluidized bed reactor are toluene, ammonia gas and air, and the molar ratio is 1: 3: 15, the reaction temperature is 400 ℃, and the gas apparent linear velocity is 0.5 m/s. The superficial linear velocity of the gas in the oxygen supply heat exchanger was 0.2m/s, the yield of benzonitrile was 82.1%, and the results are detailed in Table 2.

[ example 9 ] A method for producing a polycarbonate

In the experiment, the included angle alpha of the two blades of the upper baffle plate of the component is 60 degrees, and the included angle beta of the two blades of the lower baffle plate of the component is 60 degrees. The two blades of the baffle plate on the component of the intensive mixing component are provided with openings and/or slits, and the ratio of the total area of the openings and/or slits to the area of the blades has the opening rate of 5%. The two blades of the lower baffle of the intensive mixing component are provided with openings and/or slits, and the ratio of the total area of the openings and/or slits to the area of the blades has the opening rate of 3%. The intensive mixing components are uniformly distributed in the reactor in a staggered mode, and the acute/right angle of pairwise intersection between every two adjacent intensive mixing components in the vertical direction is 90 degrees.

The reaction raw materials in the dense-phase zone of the fluidized bed reactor are toluene, ammonia gas and air, and the molar ratio is 1: 3: 15, the reaction temperature is 400 ℃, and the gas apparent linear velocity is 0.5 m/s. The superficial linear velocity of the gas in the oxygen supply heat exchanger was 0.2m/s, the yield of benzonitrile was 82.9%, and the results are shown in Table 2.

[ example 10 ]

The reaction raw materials in the dense-phase zone of the fluidized bed reactor are toluene, ammonia gas and air, and the molar ratio is 1: 3: 15, the reaction temperature is 400 ℃, and the gas apparent linear velocity is 0.2 m/s. The superficial linear velocity of the gas in the oxygen supply heat exchanger was 0.2m/s, the yield of benzonitrile was 82.2%, and the results are detailed in Table 2.

[ example 11 ]

The reaction raw materials in the dense-phase zone of the fluidized bed reactor are toluene, ammonia gas and air, and the molar ratio is 1: 3: 15, the reaction temperature is 400 ℃, and the gas apparent linear velocity is 0.8 m/s. The superficial linear velocity of the gas in the oxygen supply heat exchanger was 0.2m/s, the yield of benzonitrile was 81.8%, and the results are shown in Table 3.

[ example 12 ]

The reaction raw materials in the dense-phase zone of the fluidized bed reactor are toluene, ammonia gas and air, and the molar ratio is 1: 3: 15, the reaction temperature is 400 ℃, and the gas apparent linear velocity is 0.5 m/s. The superficial linear velocity of the gas in the oxygen-supplying heat exchanger was 0.05m/s, the yield of benzonitrile was 81.9%, and the results are shown in Table 3.

[ example 13 ]

The reaction raw materials in the dense-phase zone of the fluidized bed reactor are toluene, ammonia gas and air, and the molar ratio is 1: 3: 15, the reaction temperature is 400 ℃, and the gas apparent linear velocity is 0.5 m/s. The superficial linear velocity of the gas in the oxygen supply heat exchanger was 0.4m/s, the yield of benzonitrile was 83.0%, and the results are detailed in Table 3.

[ COMPARATIVE EXAMPLE 1 ]

After being vaporized, toluene and ammonia and air enter a dense-phase region of a reactor of a fluidized bed reactor from a gas distribution chamber, and then carry out aromatic ammoxidation reaction under the action of a catalyst; after the corresponding cyanobenzene generated by the reaction and a small part of catalyst leave a dense-phase zone of the reactor, the cyanobenzene enters a dilute-phase zone of the reactor, after the cyanobenzene is separated by a cyclone separator, the cyanobenzene flows out of a fluidized bed reactor and is received by methods such as condensation or solvent absorption, and is refined by methods such as rectification or recrystallization to obtain product gas, and the catalyst flows into the dense-phase zone of the reactor through a cyclone dipleg after being separated; after leaving the fluidized bed reactor, part of catalyst in the dense-phase zone of the reactor flows into the oxygen supply heat exchanger through the circulating feeding pipe to be fully mixed and contacted with air, so that high-efficiency heat exchange is carried out, meanwhile, the catalyst lattice oxygen is supplemented, and then the catalyst returns to the fluidized bed reactor through the circulating return pipe to continuously participate in the reaction. No intensive mixing elements are provided.

The reaction raw materials in the dense-phase zone of the fluidized bed reactor are toluene, ammonia gas and air, and the molar ratio is 1: 3: 15, reaction temperature 400 ℃, gas apparent linear velocity of 0.5m/s, benzonitrile yield of 81.3%, and the results are detailed in Table 3.

[ COMPARATIVE EXAMPLE 2 ]

After being vaporized, toluene and ammonia and air enter a dense-phase region of a reactor of a fluidized bed reactor from a gas distribution chamber, and then carry out aromatic ammoxidation reaction under the action of a catalyst; after the corresponding cyanobenzene produced by the reaction and a small part of catalyst leave the dense-phase zone of the reactor, the cyanobenzene enters the dilute-phase zone of the reactor, after the cyanobenzene is separated by a cyclone separator, the cyanobenzene flows out of the fluidized bed reactor and is received by methods such as condensation or solvent absorption, and the like, and the product gas is obtained by refining by methods such as rectification or recrystallization, and after the catalyst is separated, the catalyst flows into the dense-phase zone of the reactor through a cyclone dipleg. The oxygen supply heat exchanger is not arranged, and the prior art is adopted: a reactor, which is internally provided with an internal heat exchanger. The reaction raw materials in the dense-phase zone of the fluidized bed reactor are toluene, ammonia gas and air, and the molar ratio is 1: 3: 15, reaction temperature 400 ℃, gas superficial linear velocity 0.5m/s, benzonitrile yield 79.3%, results are detailed in Table 3.

TABLE 1

TABLE 2

TABLE 3

Claims

1. A combined fluidized bed reactor for ammoxidation of aromatic hydrocarbon comprises a fluidized bed reactor (1), a gas distribution chamber (4), a circulating feed pipe (9), an oxygen supply heat exchanger (10) and a circulating return pipe (13); the fluidized bed reactor (1) comprises a reactor dense-phase zone (3) and a reactor dilute-phase zone (2); at least one group of forced mixing components (11) are arranged in the oxygen supply heat exchanger (10);

wherein, the upper end of the reactor dense phase zone (3) of the fluidized bed reactor (1) is communicated with an oxygen supply heat exchanger (10) through a circulating feeding pipe (9); the lower end of a reactor dense-phase area (3) of the fluidized bed reactor (1) is communicated with an oxygen supply heat exchanger (10) through a circulating return pipe (13); the fluidized bed reactor (1) is communicated with the gas distribution chamber (4); the side surface of the upper end of the cyclone separator (7) is communicated with the dilute phase zone (2) of the reactor; the bottom is communicated with a dense-phase zone (3) of the reactor through a cyclone dipleg (6);

wherein the intensive mixing component (11) is formed by combining a component upper baffle (21) and a component lower baffle (22); the component upper baffle (21) and the component lower baffle (22) are formed by combining two blades in a V shape and an inverted V shape respectively; the included angle alpha of the two blades of the upper baffle of the component is not less than the included angle beta of the two blades of the lower baffle of the component;

wherein, two blades of the baffle (21) on the component of the intensive mixing component (11) are provided with openings and/or slits, and the opening rate of the ratio of the total area of the openings and/or slits to the area of the blades is 3% -15%;

wherein, the two blades of the lower baffle plate (22) of the strong mixing component (11) are provided with openings and/or slits, and the opening rate of the ratio of the total area of the openings and/or slits to the area of the blades is 1% -10%;

the forced mixing components (11) are uniformly distributed in the oxygen supply heat exchanger (10) in a staggered mode, and acute/right-angle angles of pairwise intersection between every two adjacent forced mixing components (11) in the vertical direction are 30-90 degrees;

wherein the intensive mixing members (11) are parallel on the same cross section, and the distance between the intensive mixing members (11) adjacent in the horizontal direction is not less than 100 mm.

2. The combined fluidized bed reactor for ammoxidation of aromatic hydrocarbon according to claim 1, wherein the ratio of the cross section of the oxygen-supplying heat exchanger (10) to the cross-sectional area of the fluidized bed reactor (1) is not more than 0.5.

3. An aromatic ammoxidation combined fluidized bed reaction method, which adopts the aromatic ammoxidation combined fluidized bed reaction device of any one of claims 1 to 2, and aromatic hydrocarbon/ammonia are reacted by the reaction device to obtain aromatic nitrile.

4. The combined fluidized bed reaction process for ammoxidation of aromatic hydrocarbons according to claim 3, comprising the steps of:

(a) after being vaporized, the aromatic hydrocarbon/ammonia and air enter a dense-phase region (3) of a reactor of the fluidized bed reactor (1) from an air distribution chamber (4), and then the aromatic hydrocarbon ammoxidation reaction is carried out under the action of a catalyst;

(b) after leaving the dense-phase zone (3) of the reactor, the aromatic nitrile effluent (8) and a small part of catalyst generated by the reaction enter the dilute-phase zone (2) of the reactor, after being separated by a cyclone separator (7), the aromatic nitrile effluent (8) flows out of the fluidized bed reactor (1), is received by methods such as condensation or solvent absorption, and is refined by methods such as rectification or recrystallization to obtain product gas, and the catalyst flows into the dense-phase zone (3) of the reactor through a cyclone dipleg (6) after being separated;

(c) after a part of catalyst in the dense-phase zone (3) of the reactor leaves the fluidized bed reactor (1), the catalyst flows into an oxygen supply heat exchanger (10) through a circulating feeding pipe (9) and is fully mixed and contacted with air under the action of a strong mixing component to carry out high-efficiency heat exchange, meanwhile, the catalyst lattice oxygen is supplemented, and then the catalyst returns to the fluidized bed reactor (1) through a circulating return pipe (13) to continuously participate in the ammoxidation reaction of aromatic hydrocarbon.

5. The aromatic ammoxidation combined fluidized bed reaction method according to claim 4, wherein in the dense phase zone (3) of the reactor, the reaction raw materials are aromatic hydrocarbons and derivatives thereof of C7-C8, ammonia gas and air, and the molar ratio is 1: (1-10): (10-40), the reaction temperature is 350-480 ℃, the pressure is 0.01-0.11 MPa, and the gas apparent linear speed is 0.2-0.8 m/s; the surface line-observing speed of the gas in the oxygen supply heat exchanger (10) is 0.05-0.4 m/s.