Tail gas treatment device for refining isocyanate

Abstract

The tail gas treatment device comprises a tower body, the side wall of the tower body is provided with an amine liquid feeding port and an MDI tail gas inlet, the top of the tower body is provided with a tail gas outlet, a fixed feeding pipe, a spraying assembly and a driving part are arranged in the tower body, one end of the fixed feeding pipe is connected to the amine liquid feeding port, and the other end of the fixed feeding pipe is connected to the MDI tail gas inlet. The spraying assembly is rotatably connected to the other end of the fixed feeding pipe, the driving part is used for driving the spraying assembly to rotate, and the MDI tail gas inlet is located below the spraying assembly. The MDI tail gas treated by the tail gas treatment device enters a vacuum system, so that MDI and phenyl isocyanate substances can be prevented from entering the vacuum system, the vacuum system can be prevented from being blocked, and a normal production process is ensured.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of isocyanate production, in particular to a tail gas treatment device for refined isocyanate. BACKGROUND

[0002] At present, the production process of diphenylmethane diisocyanate (MDI) mainly adopts the phosgene method, and the synthesized MDI is a crude product including monomer MDI and polymerized MDI. The monomer MDI and the polymerized MDI products differ in performance and can be used for synthesizing different types of downstream products. In order to improve the practical value of the products, the crude MDA is usually separated into monomer MDI and polymerized MDI by using a rectification method. Since MDI is a heat-sensitive substance, the crude MDI product needs to be rectified and purified under vacuum conditions, and the tail gas of the rectification process will carry a part of light component impurities (including phenyl isocyanate, monomer MDI, chlorobenzene and the like) into the vacuum system. Among them, the light component substances such as phenyl isocyanate and monomer MDI have a low freezing point and will rapidly freeze and block the vacuum system in the vacuum system, thereby affecting the normal production and operation of the MDI device.

[0003] CN116492990A discloses preparation of an adsorbent for adsorbing MDI and PI (phenyl isocyanate) in MDI tail gas, the content of MDI is less than 0.1%, and the content of PI is less than 1%. Although the adsorption method is used to reduce the contents of MDI and PI in the tail gas, the adsorption period of the adsorbent needs to be considered, and the adsorbed MDI and PI will cause resource waste.

[0004] CN112023433B mentions that the MDI production tail gas is subjected to condensation treatment through two-stage deep cooling heat exchangers before entering the vacuum unit; the condensation temperature in the first-stage deep cooling heat exchanger is 0-15℃, which is used for cooling most of the MDI into solid; the condensation temperature in the second-stage deep cooling heat exchanger is -45- -25℃, which is used for cooling most of the PI and part of the chlorobenzene into solid. After two-stage deep cooling treatment, the residual PI in the tail gas is removed by spraying high-boiling-point polar organic matter, new substances are introduced, and separation treatment is needed, and the PI after spraying is not recycled in this patent. The substances condensed in the second-stage deep cooling heat exchanger and the condensate at the outlet of the vacuum unit are collected into a chlorobenzene tank; hydrochloric acid is added to the tank, and the PI reacts with water in the presence of hydrochloric acid to generate aniline hydrochloride; after the reaction, the water phase and the chlorobenzene phase are separated, the separated chlorobenzene is returned to the crude MDI production process as a reaction solvent, and the separated water phase containing aniline hydrochloride is returned to the front condensation reaction process as a reaction raw material. In summary, the treatment process of the MDI production tail gas in this patent is complex, and the high-boiling-point polar organic matter introduced from outside the system needs to be further treated.

[0005] CN114292211B mentions that the generation of phenyl isocyanate is due to the presence of untransposed secondary amines and other substances when amines are generated in the condensation process, which decompose to generate aniline and methylaniline in the photochemical stage, and then photochemical generation of phenyl isocyanate substances. By controlling the presence of untransposed substances in the condensation stage, the generation of phenyl isocyanate in the photochemical process is reduced, but the presence of phenyl isocyanate also inevitably affects the vacuum system in the photochemical stage.

[0006] The prior art has the following defects: 1) The process for removing MDI and phenyl isocyanate in MDI tail gas in the prior art is complex, cannot be further recycled, causes waste of resources, and affects the yield of MDI. 2) The generation of phenyl isocyanate is controlled in the MDA condensation stage, but the generation of phenyl isocyanate cannot be completely avoided, and MDI is contained in the MDI tail gas, which still has the risk of blocking the vacuum system. Practical new type content

[0007] Therefore, it is necessary to provide a tail gas treatment device for refining isocyanate, which can prevent phenyl isocyanate and MDI substances from entering the vacuum system, causing the vacuum system to be blocked, and affecting the normal production process.

[0008] A tail gas treatment device for refining isocyanate, comprising a tower body, an amine liquid inlet and an MDI tail gas inlet are arranged on the side wall of the tower body, a tail gas outlet is arranged at the top of the tower body, a fixed feeding pipe, a spraying assembly and a driving member are arranged in the tower body, one end of the fixed feeding pipe is connected to the amine liquid inlet, the spraying assembly is rotatably connected to the other end of the fixed feeding pipe, the driving member is used to drive the spraying assembly to rotate, and the MDI tail gas inlet is located below the spraying assembly.

[0009] In one embodiment, the spraying assembly comprises a first conveying pipe, a horizontal spraying pipe and a vertical spraying pipe, the first conveying pipe is arranged to extend along the axial direction of the tower body, the first conveying pipe is rotatably connected to the fixed feeding pipe, the driving member is used to drive the first conveying pipe to rotate around its central axis, the inside of the first conveying pipe is in communication with the inside of the fixed feeding pipe, the horizontal spraying pipe is connected to the first conveying pipe in a horizontal manner, and the vertical spraying pipe extends along the axial direction of the tower body and is connected to the horizontal spraying pipe, the horizontal spraying pipe is in communication with the first conveying pipe and the vertical spraying pipe, and a plurality of spray holes are arranged on the horizontal spraying pipe and the vertical spraying pipe.

[0010] In one embodiment, the spraying assembly further comprises a stirring plate, the stirring plate is arranged to extend along the axial direction of the tower body and is connected to the vertical spraying pipe.

[0011] In one of the embodiments, the spraying assembly further comprises a second delivery pipe above the transverse spraying pipe, the second delivery pipe is transversely connected to the first delivery pipe, and the second delivery pipe is provided with a plurality of nozzles on the downward side wall.

[0012] In one of the embodiments, a bearing is arranged between the fixed feeding pipe and the spraying assembly, the bearing comprises a fixed part and a rotating part, the rotating part is rotatably connected to the fixed part, the fixed part is connected to the fixed feeding pipe, the rotating part is connected to the spraying assembly, the rotating part is provided with a first gear, the driving member is a motor, the motor is arranged outside the tower body, the output shaft of the motor extends into the tower body, the output shaft of the motor is provided with a second gear, and the second gear is in meshing transmission with the first gear.

[0013] In one of the embodiments, a condensing sleeve is arranged on the outer periphery of the tower body, and the condensing sleeve is above the fixed feeding pipe and the spraying assembly.

[0014] In one of the embodiments, the amine liquid feeding port is connected with a preheater through a pipeline, and the preheater is used for preheating the amine liquid entering the amine liquid feeding port.

[0015] In one of the embodiments, a heating sleeve is arranged on the outer periphery of the tower body, and the heating sleeve corresponds to the outer periphery of the spraying assembly.

[0016] In one of the embodiments, the tower body is provided with a discharge port at the bottom, the discharge port is sequentially connected with a filter and a circulating pump through pipelines, the circulating pump is connected to the amine liquid feeding port through a pipeline, and the filter is provided with a solid residue outlet.

[0017] In one of the embodiments, two filters are arranged in parallel.

[0018] In one of the embodiments, the side wall of the tower body is further provided with a liquid level meter, and the liquid level meter is below the MDI tail gas inlet.

[0019] Compared with the prior art, the tail gas treatment device for refined isocyanate provided by the application has the following advantages: when in use, amine liquid is introduced from the amine liquid feeding port, and MDI tail gas to be treated is introduced into the tower body from the MDI tail gas inlet; since the tower body is provided with a fixed feeding pipe, a spraying assembly and a driving member, the amine liquid enters the fixed feeding pipe from the amine liquid feeding port, and then enters the spraying assembly through the fixed feeding pipe, and finally is sprayed into the tower body from the spraying assembly; since the MDI tail gas inlet is located below the spraying assembly, the amine liquid above is sprayed downward, and the MDI tail gas below rises upward, so that the amine liquid can contact the MDI tail gas and react with the MDI tail gas, thereby generating solid urea substances, so that the MDI and phenyl isocyanate substances in the MDI tail gas can be removed; the MDI tail gas after the removal of the MDI and phenyl isocyanate substances continues to rise and is finally discharged from the tail gas outlet, while the solid urea substances fall to the bottom of the tower and can be recycled; since the driving member is arranged, the driving member can drive the spraying assembly to rotate, so that the amine liquid sprayed from the spraying assembly is more uniformly distributed in the tower body, and the rotation of the spraying assembly controlled by the driving member can disturb the air flow, so that the amine liquid can fully contact the MDI and phenyl isocyanate substances in the MDI tail gas and react with the MDI and phenyl isocyanate substances; the MDI tail gas treated by the tail gas treatment device can enter the vacuum system again, so that the vacuum system is prevented from being blocked, thereby ensuring the normal production process. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description only show some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without any creative effort on the basis of these drawings.

[0021] Figure 1 FIG. 1 is a structural schematic view of a tail gas treatment device for refined isocyanate according to an embodiment of the present application;

[0022] Figure 2 FIG. 2 is a structural schematic view of a spraying assembly according to an embodiment of the present application.

[0023] FIG. 1 is a structural schematic view of a tail gas treatment device for refined isocyanate according to an embodiment of the present application; FIG. 2 is a structural schematic view of a spraying assembly according to an embodiment of the present application; FIG. 3 is a structural schematic view of a driving member according to an embodiment of the present application; and FIG. 4 is a structural schematic view of a preheater according to an embodiment of the present application. 1, tower body; 11, amine liquid feeding port; 12, MDI tail gas inlet; 13, tail gas outlet; 14, discharge port; 15, liquid level meter; 2, fixed feeding pipe; 21, bearing; 3, spraying assembly; 31, first conveying pipe; 32, transverse spray pipe; 33, vertical spray pipe; 34, spray hole; 35, stirring plate; 36, second conveying pipe; 37, nozzle; 4, driving member; 5, condensing sleeve; 6, heating sleeve; 7, preheater; 8, filter; 9, circulating pump. DETAILED DESCRIPTION

[0024] In order to make the above objectives, features and advantages of the present application more clear and comprehensible, the detailed description of the specific embodiments of the present application is made below with reference to the accompanying drawings. In the following description, a lot of specific details are set forth in order to provide a thorough understanding of the present application. However, the present application can be implemented in many different ways other than the one described herein, and one of ordinary skill in the art can make similar improvements without departing from the scope of the present application, and therefore the present application is not limited to the specific embodiments disclosed below.

[0025] It is to be noted that when a component is referred to as being "on" or "disposed on" another component, it can be directly on the other component or there can be intervening components present. When a component is referred to as being "connected" to another component, it can be directly connected to the other component or there can be intervening components present. The terms "vertical", "horizontal", "upper", "lower", "left", "right", and similar terms as used in the description of the specification are for the purpose of illustration only and do not indicate an exclusive orientation.

[0026] In addition, the terms "first", "second", and the like, are used merely to describe items that differ from one another, without necessarily implying a relative importance or a quantity. Thus, a feature defined with "first" or "second" can implicitly or explicitly include at least one of the features. In the description of the specification, the meaning of "a plurality" is at least two, such as two, three, etc., unless otherwise specifically defined.

[0027] In the present application, unless otherwise explicitly specified and limited, "on", "under", "above", and "over" of a first feature to a second feature can mean that the first feature is in direct contact with the second feature, or the first feature is indirectly in contact with the second feature through an intermediate medium. Moreover, "above", "over", and "on" of the first feature to the second feature can mean that the first feature is directly above or obliquely above the second feature, or only means that the first feature is horizontally higher than the second feature. "Below", "under", and "underneath" of the first feature to the second feature can mean that the first feature is directly below or obliquely below the second feature, or only means that the first feature is horizontally lower than the second feature.

[0028] Unless otherwise defined, all technical and scientific terms used in the specification of the present application have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs. The terms used in the specification of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application. The term "and / or" used in the specification of the present application includes any and all combinations of one or more of the associated listed items.

[0029] Please refer to Figure 1 and Figure 2The application provides a tail gas treatment device for refined isocyanate, which comprises a tower body 1, an amine liquid inlet 11 and an MDI tail gas inlet 12 are arranged on the side wall of the tower body 1, a tail gas outlet 13 is arranged at the top of the tower body 1, a fixed feeding pipe 2, a spraying assembly 3 and a driving piece 4 are arranged in the tower body 1, one end of the fixed feeding pipe 2 is connected to the amine liquid inlet 11, the spraying assembly 3 is rotatably connected to the other end of the fixed feeding pipe 2, the driving piece 4 is used for driving the spraying assembly 3 to rotate, and the MDI tail gas inlet 12 is located below the spraying assembly 3. When the tail gas treatment device is used, amine liquid is fed from the amine liquid inlet 11, and MDI tail gas to be treated is fed into the tower body 1 from the MDI tail gas inlet 12. Since the fixed feeding pipe 2, the spraying assembly 3 and the driving piece 4 are arranged in the tower body 1, the amine liquid enters the fixed feeding pipe 2 from the amine liquid inlet 11, enters the spraying assembly 3 through the fixed feeding pipe 2 and is finally sprayed into the tower body 1 from the spraying assembly 3. Since the MDI tail gas inlet 12 is located below the spraying assembly 3, the amine liquid above is sprayed downward, and the MDI tail gas below rises upward, so that the amine liquid can contact the MDI tail gas and react to generate solid urea substances, so that the MDI and phenyl isocyanate substances in the MDI tail gas can be removed. The MDI tail gas after the removal of the MDI and phenyl isocyanate substances continues to rise and is finally discharged from the tail gas outlet 13, and the solid urea substances fall to the bottom of the tower and can be recycled. Since the driving piece 4 is arranged, the driving piece 4 can drive the spraying assembly 3 to rotate, so that the amine liquid sprayed by the spraying assembly is more uniformly distributed in the tower body 1, and the rotation of the spraying assembly 3 controlled by the driving piece 4 can play a role in disturbing the airflow, so that the amine liquid can fully contact the MDI and phenyl isocyanate substances in the MDI tail gas and react. The MDI tail gas treated by the tail gas treatment device can enter the vacuum system again, so that the vacuum system can be prevented from being blocked, thereby ensuring normal production process.

[0030] Further, the spraying assembly 3 comprises a first conveying pipe 31, a transverse spraying pipe 32 and a vertical spraying pipe 33. The first conveying pipe 31 is arranged along the axial direction of the tower body 1 and is rotationally connected with the fixed feeding pipe 2. The driving member 4 is configured to drive the first conveying pipe 31 to rotate about the central axis thereof, that is, the first conveying pipe 31 can rotate about the central axis thereof under the driving of the driving member 4. The interior of the first conveying pipe 31 is in communication with the interior of the fixed feeding pipe 2. The transverse spraying pipe 32 is transversely connected with the first conveying pipe 31, and the vertical spraying pipe 33 extends along the axial direction of the tower body 1 and is connected with the transverse spraying pipe 32. The transverse spraying pipe 32 is in communication with the first conveying pipe 31 and the vertical spraying pipe 33, and a plurality of spraying holes 34 are arranged on the transverse spraying pipe 32 and the vertical spraying pipe 33. In this way, the amine solution first enters the first conveying pipe 31 from the fixed feeding pipe 2 and then enters the transverse spraying pipe 32 and the vertical spraying pipe 33 from the first conveying pipe 31. Since the plurality of spraying holes 34 are arranged on the transverse spraying pipe 32 and the vertical spraying pipe 33, the amine solution can be sprayed from the transverse spraying pipe 32 and the vertical spraying pipe 33. Meanwhile, the transverse spraying pipe 32 and the vertical spraying pipe 33 can rotate with the first conveying pipe 31, so as to form a three-dimensional spraying coverage, thereby making the distribution of the amine solution in the tower body 1 more uniform, and further making the amine solution fully contact with the rising MDI tail gas, thereby promoting the reaction between the amine solution and the MDI tail gas.

[0031] In the embodiment, the spraying holes 34 are circular holes, which are simple in structure, but are not limited thereto. The spraying holes 34 can also be square holes, oval holes, hexagonal holes or other shaped through holes, which are not limited in the present application.

[0032] The spraying holes 34 are uniformly arranged on the circumferential side of the transverse spraying pipe 32 and the vertical spraying pipe 33, so that the amine solution can be sprayed from all around of the transverse spraying pipe 32 and the vertical spraying pipe 33.

[0033] Further, the spraying assembly 3 further comprises a stirring plate 35, which is arranged along the axial direction of the tower body 1 and is connected with the vertical spraying pipe 33. The stirring plate 35 can disturb the airflow, thereby promoting the amine solution to fully contact with the MDI tail gas, and further promoting the reaction between the amine solution and the MDI tail gas.

[0034] In this embodiment, three layers of transverse nozzles 32 are connected to the first delivery pipe 31. Each layer of transverse nozzles 32 includes four transverse nozzles 32 arranged in a "+" shape. One end of each transverse nozzle 32 is connected to the first delivery pipe 31, and the other end is connected to a vertical nozzle 33. There are four vertical nozzles 33, and each vertical nozzle 33 is connected to one of the three layers of transverse nozzles 32. This ensures that a large amount of amine liquid is sprayed around the spraying assembly 3. At least one stirring plate 35 is provided on the outer wall of each vertical nozzle 33, so that the stirring plate 35 can fully agitate the airflow when the spraying assembly 3 rotates. Of course, in other embodiments, the transverse nozzles 32 can also be configured as one, two, four, or other layers, and the transverse nozzles 32 in each layer can also be arranged in a "X" shape or other ways. This application does not impose specific limitations on the number and arrangement of the first delivery pipe 31, transverse nozzles 32, vertical nozzles 33, and stirring plates 35.

[0035] The spraying assembly 3 also includes a second delivery pipe 36 located above the transverse spray pipe 32. The second delivery pipe 36 is transversely connected to the first delivery pipe 31, and a plurality of nozzles 37 are provided on the downward-facing side wall of the second delivery pipe 36. In this way, the second delivery pipe 36 can deliver amine liquid and spray it out from the nozzles 37. The amine liquid droplets sprayed out through the nozzles 37 can further intercept small amounts of impurities and entrained solid urea substances in the rising MDI exhaust gas, thereby further removing MDI and phenyl isocyanate substances from the MDI exhaust gas.

[0036] In this application, the spraying assembly 3 rotates around the central axis of the first conveying pipe 31. Further, a bearing 21 is provided between the fixed feed pipe 2 and the spraying assembly 3. The bearing 21 includes a fixed part and a rotating part, which are rotatably connected to the fixed part. The fixed part is connected to the fixed feed pipe 2, and the rotating part is connected to the spraying assembly 3. Specifically, the rotating part is connected to the first conveying pipe 31. A first gear is provided on the rotating part, and the driving component 4 is a motor. The motor is located outside the tower body 1, and its output shaft extends into the tower body 1. The motor's output shaft has a second gear, which meshes with the first gear for transmission. Thus, when the motor starts, the output shaft drives the second gear to rotate, and the rotation of the rotating part is controlled by the meshing of the second and first gears, thereby causing the spraying assembly 3 to rotate together with the rotating part.

[0037] It is understandable that the motor is located outside the tower body 1, and the output shaft of the motor extends into the tower body 1, so as to facilitate the output shaft to drive the rotating part to rotate.

[0038] Further, the outer periphery of the tower body 1 is provided with a condensing sleeve 5, which is located above the fixed feed pipe 2 and the spraying assembly 3. The condensing sleeve 5 has a condensing liquid inlet and a condensing liquid outlet. In this way, the part of the tower body 1 above the fixed feed pipe 2 and the spraying assembly 3 can be cooled by the condensing sleeve 5, so that the MDI tail gas is condensed before being discharged from the tail gas outlet 13 and entering the vacuum system.

[0039] Further, the outer periphery of the tower body 1 is provided with a heating sleeve 6, which corresponds to the outer periphery of the spraying assembly 3. It can be understood that the heating sleeve 6 has a heat source inlet and a heat source outlet. In this way, the heating sleeve 6 can effectively control the reaction temperature of the amine liquid and the MDI tail gas, so that the MDI and phenyl isocyanate in the amine liquid and the MDI tail gas can fully react.

[0040] Further, the amine liquid inlet 11 is connected with a preheater 7 through a pipeline. The preheater 7 is used to preheat the amine liquid entering the amine liquid inlet 11. In this way, the amine liquid can be preheated to the reaction temperature, thereby facilitating the full reaction of the amine liquid and the MDI tail gas and improving the removal efficiency of the MDI and phenyl isocyanate in the MDI tail gas.

[0041] Further, the bottom of the tower body 1 is provided with a discharge outlet 14, which is connected with a filter 8 and a circulating pump 9 in sequence through a pipeline. The circulating pump 9 is connected with the amine liquid inlet 11 through a pipeline. The filter 8 is provided with a solid residue outlet. In this way, the liquid amine liquid and the solid urea substance can be separated by the filter 8. The amine liquid can be recycled to the tower body 1 by the circulating pump 9, and the urea substance can be discharged through the solid residue outlet for recycling. After the urea substance is recycled, it can be decomposed to generate amine compounds with amino groups and isocyanate. The amine compounds with amino groups are used as raw materials to synthesize isocyanate, and the isocyanate is separated and enters the isocyanate product system, thereby reducing the production cost of isocyanate.

[0042] Further, the filter 8 is provided in two, and the two filters 8 are connected in parallel. In this way, one of the filters 8 can be used to filter the solid-liquid mixture at the bottom of the tower body 1, and the other filter 8 can be used as a backup. When the solid substance slurry in the filter 8 accumulates to a certain amount and needs to be unloaded, the backup filter 8 is used for filtering, and the two filters 8 can be used alternately.

[0043] Further, the side wall of the tower body 1 is also provided with a liquid level meter 15, which is located below the MDI tail gas inlet 12. The liquid level meter 15 can be used to detect the liquid level in the tower body 1 in real time, so as to avoid too much amine liquid remaining at the bottom of the tower body 1 after reaction and affecting the feeding of the MDI tail gas inlet 12.

[0044] The tail gas treatment device for refined isocyanate provided by the application can remove MDI and phenyl isocyanate substances in MDI tail gas by treating the MDI tail gas, thereby avoiding the blockage of the vacuum system and ensuring the normal production process. In addition, the generated urea substances can be recycled, thereby reducing the production cost of isocyanate.

[0045] The technical features of the above-described embodiments can be combined in any manner. In order to make the description simple, all possible combinations of the technical features in the above-described embodiments are not described, however, as long as the combinations of the technical features do not exist contradictory, they should be considered as the scope of the present disclosure.

[0046] The above-described embodiments only express several implementation manners of the present application, the description is more specific and detailed, but it should not be understood as a limitation on the patent application scope. It should be pointed out that, for ordinary skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are all within the protection scope of the present application. Therefore, the patent protection scope of the present application should be subject to the appended claims.

Claims

1. An apparatus for treating off-gas from the refining of isocyanates, characterized in that The tower body is provided with an amine liquid inlet and an MDI tail gas inlet on the side wall, and is provided with a tail gas outlet at the top, and is provided with a fixed feeding pipe, a spraying assembly and a driving member inside, one end of the fixed feeding pipe is connected to the amine liquid inlet, the spraying assembly is rotatably connected to the other end of the fixed feeding pipe, and the driving member is used to drive the spraying assembly to rotate, and the MDI tail gas inlet is located below the spraying assembly.

2. The isocyanate refined tail gas treatment device according to claim 1, characterized by The spraying assembly comprises a first conveying pipe, a transverse spray pipe and a vertical spray pipe, The first conveying pipe is arranged in the axial direction of the tower body, the first conveying pipe is rotatably connected to the fixed feeding pipe, the driving member is used to drive the first conveying pipe to rotate around its central axis, and the inside of the first conveying pipe is in communication with the inside of the fixed feeding pipe, The transverse spray pipe is transversely connected to the first conveying pipe, and the vertical spray pipe extends in the axial direction of the tower body and is connected to the transverse spray pipe, The transverse spray pipe communicates the first conveying pipe and the vertical spray pipe, and a plurality of spray holes are arranged on the transverse spray pipe and the vertical spray pipe.

3. The apparatus for treating exhaust gas of refined isocyanate according to claim 2, characterized by The spraying assembly further comprises a stirring plate arranged in the axial direction of the tower body and connected to the vertical spray pipe.

4. The apparatus for treating exhaust gas of refined isocyanate according to claim 2, characterized by The spraying assembly further comprises a second conveying pipe located above the transverse spray pipe, the second conveying pipe is transversely connected to the first conveying pipe, and a plurality of nozzles are arranged on the downward side wall of the second conveying pipe.

5. The isocyanate fine purification tail gas treatment device according to claim 1, characterized by A bearing is arranged between the fixed feeding pipe and the spraying assembly, the bearing comprises a fixed part and a rotating part, the rotating part is rotatably connected to the fixed part, the fixed part is connected to the fixed feeding pipe, the rotating part is connected to the spraying assembly, a first gear is arranged on the rotating part, the driving member is a motor, the motor is arranged outside the tower body, the output shaft of the motor extends into the tower body, a second gear is arranged on the output shaft of the motor, and the second gear is in meshing transmission with the first gear.

6. The isocyanate fine purification tail gas treatment device according to claim 1, characterized by A condensing sleeve is arranged on the outer periphery of the tower body, and the condensing sleeve is located above the fixed feeding pipe and the spraying assembly.

7. The isocyanate fine purification tail gas treatment device according to claim 1, characterized by A preheater is connected to the amine liquid inlet through a pipeline, and the preheater is used to preheat the amine liquid entering the amine liquid inlet. And / or, a heating sleeve is arranged on the outer periphery of the tower body, and the heating sleeve corresponds to the outer periphery of the spraying assembly.

8. The isocyanate fine purification tail gas treatment device according to claim 1, characterized by A discharge outlet is arranged at the bottom of the tower body, the discharge outlet is sequentially connected with a filter and a circulating pump through pipelines, the circulating pump is connected to the amine liquid inlet through a pipeline, and the filter is provided with a solid residue outlet.

9. The isocyanate refined tail gas treatment device according to claim 8, characterized by The filter is provided in two, and the two filters are connected in parallel.

10. The isocyanate fine purification apparatus according to claim 1, wherein A liquid level meter is further arranged on the side wall of the tower body, and the liquid level meter is located below the MDI tail gas inlet.

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