A flow control device for a reaction kettle in the production of methyl isocyanate

Abstract

The present invention discloses a flow control device for a reaction kettle in the production of methyl isocyanate, which relates to the field of reaction vessels and includes a reaction kettle. A stirrer, a draft tube, an atomizer and a flow control plate are arranged in the reaction kettle. The flow control plate is arranged above the draft tube and can move axially along the reaction kettle to approach or move away from the draft tube. A number of conical holes in a shape of being large at the top and small at the bottom are penetrated through the flow control plate. When the liquid in the reaction kettle circulates and flows, the liquid in the draft tube flows upward and gushes out from the conical holes of the flow control plate, and the gushing liquid contacts and mixes with the atomized droplets sprayed by the atomizer; by arranging the flow control plate and the conical holes formed thereon, the liquid in the draft tube flows upward and gushes out from the conical holes of the flow control plate, so as to reconstruct the liquid surface into a relatively thick umbrella-shaped liquid film with a relatively uniform distribution without affecting the stirring effect, effectively expand the liquid surface, and adjust the addition speed of the atomizer and the stirring speed in real time according to the mixing process to improve the absorption efficiency.

Description

Technical Field

[0001] The present invention relates to the technology of reaction vessels, and particularly to a flow control device for a reaction kettle in the production of methyl isocyanate. Background Art

[0002] The production process of methyl isocyanate is usually carried out in a closed reaction kettle. The main raw materials are sodium cyanate, o-dichlorobenzene and dimethyl sulfate. As the core equipment, the reaction kettle needs to have high-efficiency mixing and mass transfer capabilities. The reaction is a fast and strong exothermic process, and the reaction rate needs to be strictly controlled to avoid the generation of by-products, which puts forward high requirements for the mass transfer efficiency and temperature homogenization ability of the reaction kettle.

[0003] In the prior art, in order to improve the reaction efficiency, most processes adopt methods such as optimizing the structure of the stirring paddle and improving the dispersion degree of atomized droplets. However, under the constraint of a fixed reaction kettle diameter, the contact area between the atomized droplets and the reaction liquid is limited within the physical size range of the liquid surface. Although the traditional mechanical stirring can accelerate the liquid surface renewal rate, it cannot break through the inherent limitation of the liquid phase surface area, and the effective contact interface between the gas-liquid two phases is difficult to be further expanded. In large-scale production, relying solely on stirring may also cause local overheating or excessive shearing, affecting the product yield. Summary of the Invention

[0004] The purpose of the present invention is to provide a flow control device for a reaction kettle in the production of methyl isocyanate to solve the above deficiencies in the prior art.

[0005] To achieve the above purpose, the present invention provides the following technical solution: A flow control device for a reaction kettle in the production of methyl isocyanate, including a reaction kettle, a stirrer and a draft tube are arranged in the reaction kettle. An atomizer and a flow control plate are also arranged in the reaction kettle. The flow control plate is arranged above the draft tube and its diameter is smaller than the inner diameter of the reaction kettle. The flow control plate can move axially along the reaction kettle to approach or move away from the draft tube. A plurality of tapered holes in a shape of larger at the top and smaller at the bottom are penetrated through the flow control plate. When the liquid in the reaction kettle circulates, the liquid in the draft tube flows upward and gushes out from the tapered holes of the flow control plate, and the gushing liquid contacts and mixes with the atomized droplets sprayed by the atomizer.

[0006] Further, the number of the atomizers is multiple and they are annularly distributed along the inner wall of the reaction kettle. The nozzles of the atomizers are inclined downward, and the inclination angle is 15° - 30°.

[0007] Further, the flow control plate is in a shape of a cone protruding upward.

[0008] Further, an elastic member is arranged at the top of the flow control plate, and the elastic force of the elastic member acts on the flow control plate to make it tend to approach the draft tube.

[0009] Further, the elastic member includes a fixed seat and a first sleeve. The surface of the first sleeve is slidably connected to the inner wall of the fixed seat. The bottom of the first sleeve is connected to the flow control plate, and a first spring is sleeved on the surface of the first sleeve between the flow control plate and the fixed seat.

[0010] Further, a plurality of guide plates are arranged at positions near the circumferential side of the bottom of the flow control plate and are distributed in an annular array. The guide plates are inclined from the inner side to the outer side of the flow control plate.

[0011] Further, the aperture of the conical hole on the flow control plate gradually increases from the outside to the inside.

[0012] Further, the elastic member further includes a limiting component, and the limiting component is used to limit the rotation of the flow control plate relative to the fixed seat.

[0013] Further, the limiting component includes at least one limiting groove opened on the inner wall of the fixed seat. At least one limiting rod is slidably connected to the end of the first sleeve along its radial direction. A second spring is arranged on one side of the limiting rod, and the elastic force of the second spring acts on the limiting rod to make it have a moving tendency away from the axis direction.

[0014] Further, the guide cylinder is in a conical shape with a smaller upper part and a larger lower part.

[0015] Compared with the prior art, a flow control device for a reaction kettle in the production of methyl isocyanate provided by the present invention has the following beneficial effects:

[0016] The flow control device for the reaction kettle in the production of methyl isocyanate, by setting the flow control plate and the conical hole opened thereon, the liquid in the guide cylinder flows upward and gushes out from the conical hole of the flow control plate, so as to reconstruct the liquid surface into a relatively thick umbrella-shaped liquid film with a relatively uniform distribution without affecting the stirring effect, effectively expand the liquid surface, and adjust the addition speed of the atomizer and the stirring speed in real time according to the mixing process, thereby improving the absorption efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] 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 required to be used in the embodiments. Obviously, the drawings described below are only some embodiments recorded in the present invention, and those of ordinary skill in the art can also obtain other drawings based on these drawings.

[0018] Figure 1 It is a cross-sectional view of the overall structure of the reaction kettle provided by the embodiment of the present invention;

[0019] Figure 2 It is a schematic diagram of the liquid flow direction (the direction indicated by the dotted arrow) in the reaction kettle provided by the embodiment of the present invention;

[0020] Figure 3Schematic diagram of the structure with an elastic member provided on the flow control plate according to an embodiment of the present invention;

[0021] Figure 4 Schematic diagram of the structure of the elastic member and the limiting component provided by an embodiment of the present invention;

[0022] Figure 5 Schematic diagram of the structure of one of the limiting components provided by an embodiment of the present invention;

[0023] Figure 6 Provided by an embodiment of the present invention Figure 5 Enlarged view of part A in

[0024] Figure 7 Schematic diagram of the structure of another limiting component provided by an embodiment of the present invention;

[0025] Figure 8 Schematic diagram of the structure of the flow control plate provided by an embodiment of the present invention being a conical shape bulging upward;

[0026] Figure 9 Schematic diagram of the structure of the conical hole provided by an embodiment of the present invention having a gradually increasing aperture from the outside to the inside;

[0027] Figure 10 Schematic diagram of the structure of the flow control plate provided by an embodiment of the present invention with a flow guide plate provided at the bottom.

[0028] Explanation of reference numerals:

[0029] 1. Reaction kettle; 11. Feed inlet; 12. Observation port; 13. Jacket; 14. Liquid inlet pipe; 15. Liquid outlet pipe; 16. Discharge port; 2. Stirrer; 21. Stirring rod; 3. Draft tube; 4. Atomizer; 41. Nozzle; 42. Liquid supply assembly; 5. Flow control plate; 51. Conical hole; 52. Flow guide plate; 6. First driving member; 61. Electric telescopic rod; 62. Connecting rod; 63. Extension bracket; 7. Elastic member; 71. Fixed seat; 72. First sleeve; 73. First spring; 8. Limiting component; 801. Limiting groove; 802. Limiting rod; 803. Second spring; 804. Limiting seat; 805. First disc; 806. Second disc; 807. Third spring; 808. Second sleeve; 809. Sphere; 810. Spherical groove; 811. Support; 812. Guide rod. Detailed implementation manners

[0030] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further introduced in detail below with reference to the accompanying drawings.

[0031] Example, please refer to Figure 1 - Figure 10, A flow control device for a reaction kettle 1 in the production of methyl isocyanate, including the reaction kettle 1, on which there are a feed inlet 11, a discharge outlet 16, an observation port 12 and a jacket 13. On the jacket 13, there are a liquid inlet pipe 14 and a liquid outlet pipe 15. Inside the reaction kettle 1, there are a stirrer 2 and a draft tube 3. As Figure 1 shown, the draft tube 3 is arranged around the blades on the stirring rod 21 of the stirrer 2, and there is a certain distance between the draft tube 3 and the bottom of the reaction kettle 1. Its diameter is smaller than the inner diameter of the reaction kettle 1 and there is a gap with the inner wall of the reaction kettle 1. The blades of the stirrer 2 are radial-flow inclined-blade turbines or axial-flow impellers, etc., which are used to form a low-pressure area inside the draft tube 3. When the blades rotate, they push the fluid to move upward along the axial direction of the draft tube 3, and then flow downward along the outer ring of the draft tube 3. The fluid re-enters the draft tube 3 from the bottom of the draft tube 3 to form a closed cycle. As Figure 2 shown;

[0032] An atomizer 4 and a flow control plate 5 are also arranged inside the reaction kettle 1. The atomizer 4 is supplied with liquid through a liquid supply assembly 42 arranged outside the reaction kettle 1. The flow control plate 5 is arranged above the draft tube 3, and its diameter is smaller than the inner diameter of the reaction kettle 1. The flow control plate 5 can move axially along the reaction kettle 1 to approach or move away from the draft tube 3. A number of tapered holes 51 with a large upper part and a small lower part are penetrated through the flow control plate 5. When the liquid in the reaction kettle 1 circulates, the liquid in the draft tube 3 flows upward and gushes out from the tapered holes 51 of the flow control plate 5. The gushing liquid contacts and mixes with the atomized droplets sprayed by the atomizer 4;

[0033] When the liquid in the reaction kettle 1 forms the above-mentioned closed-circuit flow state, during the process that the flow control plate 5 moves downward and approaches the draft tube 3, the flowing fluid is blocked by the flow control plate 5 and gushes out from the tapered holes 51. When gushing out, the fluid decelerates when passing through the expanded outlet, and the kinetic energy is converted into static pressure energy, forming a thicker umbrella-shaped liquid film with uniform distribution.

[0034] During the synthesis process of methyl isocyanate, the specific implementation scenario is:

[0035] Pretreatment stage:

[0036] After cleaning the inner wall of the reaction kettle 1 (using steam jet to clean the inner wall of the reaction kettle 1 and purging with nitrogen until the moisture content), nitrogen is introduced to displace the air inside the reaction kettle 1 (inert gas protection);

[0037] Mixing stage:

[0038] Add o-dichlorobenzene solvent into the reactor 1, start the stirrer 2 to stir, then slowly add sodium cyanate, stir for a certain time to completely disperse sodium cyanate, add dimethyl sulfate through the atomizer 4 arranged in the reactor 1, and the atomizing dropping speed is adjusted in real time through a mass flowmeter. During the addition of dimethyl sulfate, cold water is introduced into the jacket 13 of the reactor 1 to control the temperature in the kettle and avoid local overheating causing violent heat release;

[0039] Reaction stage:

[0040] After the addition of dimethyl sulfate is completed, the jacket 13 is switched to heat-conducting oil for heating up. After heating up to the required temperature, the reaction is carried out. During the reaction process, continuous stirring is carried out, and the flow control plate 5 is moved to a position far away from the liquid surface. After the reaction is completed, subsequent treatment can be carried out to collect the product, and the post-treatment process is not specifically described here.

[0041] In the mixing stage of the above-mentioned embodiment, although the addition of raw materials through the atomizer 4 has practical applications in the prior art, when atomizing and spraying, only the liquid flowing to the liquid surface position can contact the atomized droplets. Although the liquid on the liquid surface is continuously refreshed under the stirring of the stirring device, due to the limitation of the cylinder diameter of the reactor 1, the area of the liquid surface is limited, and the rate of contact with the absorption droplets per unit time is limited. Even if factors such as liquid flow rate and atomization amount are increased, it is difficult to increase the upper limit. That is to say, when the diameter of the reactor 1 is certain, the contact between the atomized droplets and the reaction liquid is limited by the liquid surface area. Traditional stirring only improves the liquid surface renewal rate but cannot break through this limitation, resulting in limited absorption efficiency. By setting the flow control plate 5 and the tapered holes 51 opened thereon, the liquid in the draft tube 3 flows upward and gushes out from the tapered holes 51 of the flow control plate 5, so as to reconstruct the liquid surface into a relatively thick umbrella-shaped liquid film with a relatively uniform distribution without affecting the stirring effect, effectively expanding the liquid surface, and adjusting the addition speed of the atomizer 4 and the stirring speed in real time according to the mixing process to improve the absorption efficiency;

[0042] Specifically, after the sodium cyanate is completely dispersed, drive the flow control plate 5 to move downward. When the bottom of it contacts the circulating liquid surface, the flowing liquid is blocked by the flow control plate 5 and gushes out from the tapered holes 51. The gushing state can be adjusted by the degree of the flow control plate 5 close to the draft tube 3 and the speed of the stirring. The atomizer 4 sprays the atomized droplets onto the surface of the gushing liquid and is absorbed. Then the liquid flows towards the inner wall of the reactor 1 and is added to the original circulating liquid for further mixing, shortening the time required for the addition process of dimethyl sulfate.

[0043] In an embodiment of the present invention, the flow control plate 5 is connected to a first driving member 6 for driving it to move axially along the reactor 1;

[0044] In an embodiment of the present invention, a plurality of atomizers 4 are provided and annularly distributed along the inner wall of the reaction kettle 1. The nozzles 41 of the atomizers 4 are inclined downward, and the inclination angle is 15°-30°, so as to ensure that the atomized droplets can better cover the space in the reaction kettle 1, improve the contact efficiency between the atomized droplets and the liquid gushing out from the conical holes 51 and the reaction uniformity. At the same time, the energy loss of the droplets in the parabolic trajectory when passing through the gas-liquid interface is smaller, effectively increasing the collision absorption probability.

[0045] In an embodiment of the present invention, the flow control plate 5 is in a conical shape protruding upward. As Figure 7 shown, during the addition of dimethyl sulfate, the conical setting of the flow control plate 5 causes the liquid to gush out along the inclined surface of the flow control plate 5. Even if the liquid surface expands less when the liquid gushes out, it is larger than the liquid surface area of only circulating flow. Moreover, the inclined surface also helps the liquid that absorbs the atomized droplets to flow downward quickly and be added to the circulating liquid for further mixing. In addition, it forms a corresponding receiving angle with the inclined nozzles 41 of the atomizers 4, and the gushing liquid can further uniformly contact the droplets ejected by the atomizers 4 per unit time;

[0046] It should be understood that the angle of the flow control plate 5 in the conical shape should not be too large. The angle between its waist line and the plane where the bottom is located is 0°-20°, and it is specifically set according to the installation height of the draft tube 3 and the liquid surface height during use.

[0047] In an embodiment of the present invention, the aperture of the conical holes 51 on the flow control plate 5 gradually increases from the outside to the inside (as Figure 9 shown), so that the conical holes 51 at the initial part in contact with the circulating liquid can have a larger gushing flow rate. At the edge position, due to the slowdown of the flow rate, the setting of the smaller aperture is beneficial to form the required liquid film. And because the sizes of the droplets ejected by the atomizers 4 will also vary, relatively more droplets are likely to move to the middle area farther away from them. The increase in the flow rate of the conical holes 51 at the corresponding positions is beneficial to cope with this situation and avoid too high concentration in local areas.

[0048] In an embodiment of the present invention, an elastic member 7 is provided at the top of the flow control plate 5, and the elastic force of the elastic member 7 acts on the flow control plate 5 to make it tend to approach the draft tube 3;

[0049] In an embodiment of the present invention, the elastic member 7 includes a fixed seat 71 and a first sleeve 72. The surface of the first sleeve 72 is slidably connected to the inner wall of the fixed seat 71. The bottom of the first sleeve 72 is connected to the flow control plate 5. A first spring 73 is sleeved on the surface of the first sleeve 72 between the flow control plate 5 and the fixed seat 71. As Figure 5 or Figure 7As shown, the first driving member 6 is connected to the fixed seat 71. By driving the movement of the fixed seat 71, the flow control disk 5 is driven to move. After the flow control disk 5 enters the working position, the flow control disk 5 is in a lower initial position under its own weight. When the circulating liquid flows through the flow control disk 5, even though the conical hole 51 can be used for the flow of the liquid, the flow control disk 5 still hinders the circulating flow of the liquid. Although it is in the mixing stage at this time and will not cause a great impact on the subsequent reaction, it will still affect the stability of the liquid gushing out from the conical hole 51 and the mixing efficiency. From another perspective, the amount of liquid that can gush out from the conical hole 51 per unit time is directly related to the speed of the circulating liquid flow in addition to being limited by its own size. After the elastic member 7 is provided, when the flow rate of the circulating liquid increases, the acting force of the liquid on the flow control disk 5 will cause the flow control disk 5 to compress the first spring 73 and move upward. On the one hand, it avoids the liquid gushing out from the conical hole 51 being too fast and affecting the shape of the formed liquid film. On the other hand, the distance between the flow control disk 5 and the guide cylinder 3 increases, and the smoothness of the circulating liquid flow increases.

[0050] In an embodiment of the present invention, the first driving member 6 includes an electric telescopic rod 61. The electric telescopic rod 61 is fixedly installed on the top of the reaction kettle 1. The output shaft of the electric telescopic rod 61 extends into the reaction kettle 1 and is fixed to the extension bracket 63 through a connecting rod 62. The extension bracket 63 is fixedly connected to the fixed seat 71.

[0051] In an embodiment of the present invention, a plurality of flow guiding plates 52 are arranged at positions near the circumferential side of the bottom of the flow control disk 5 and are distributed in an annular array. The flow guiding plates 52 are inclined from the inner side to the outer side of the flow control disk 5. As Figure 10 shown, the rotating liquid will drive the flow control disk 5 to rotate under the setting of the flow guiding plates 52, causing it to rotate, further accelerating the flow of the liquid after absorbing the atomized droplets, and making it mix more fully with the circulating liquid, thereby improving the overall mixing efficiency.

[0052] After the elastic member 7 and the flow guiding plates 52 are provided, when the flow control disk 5 moves downward to the working position and contacts the circulating liquid, the flow control disk 5 will directly rotate, which is not conducive to judging whether the flow control disk 5 has moved to a suitable position (the shape of the liquid gushing out from the conical hole 51). In an embodiment of the present invention, a method for solving the above problems is provided. Specifically, the elastic member 7 further includes a limiting component 8, and the limiting component 8 is used to limit the rotation of the flow control disk 5 relative to the fixed seat 71.

[0053] In an embodiment of the present invention, a specific example of a limiting component 8 is provided, which includes at least one limiting groove 801 formed on the inner wall of the fixed seat 71. At least one limiting rod 802 is slidably connected to the end of the first sleeve 72 along its radial direction. A second spring 803 is arranged on one side of the limiting rod 802. The elastic force of the second spring 803 acts on the limiting rod 802 to make it tend to move away from the axis direction. As Figure 5 and Figure 6 shown, a support 811 is fixedly installed on the top of the first sleeve 72. A guide rod 812 is fixedly connected to one side of the support 811. The guide rod 812 is slidably connected to the inner wall of the limiting rod 802. The end of the limiting rod 802 is triangular or arc-shaped. Figure 6 Taking the triangular shape as an example in

[0054]

[0055] Figure 7 As Figure 7

[0055] Figure 7 In an embodiment of the present invention, another specific example of the limiting component 8 is provided, which includes a limiting seat 804 fixedly connected to the bottom of the first sleeve 72. A first disc 805 and a second disc 806 are arranged in the inner cavity of the annular limiting seat 804. A third spring 807 is arranged between the first disc 805 and the inner wall of the annular limiting seat 804. The second disc 806 is located below the first disc 805. A second sleeve 808 is fixedly connected to the bottom of the second disc 806. The bottom of the second sleeve 808 is fixedly connected to the top of the flow control disc 5. The annular limiting seat 804 is rotatably connected to the surface of the second sleeve 808. A ring of spheres 809 distributed in an annular array is installed on the top of the second disc 806. The center of the sphere 809 is below the plane where the top of the second disc 806 is located. A spherical surface groove 810 adapted to each sphere 809 is formed on the bottom of the first disc 805;

[0055] As Figure 7As shown, the difference between this method and the previous one is that the previous method directly limits the position in the radial direction, while this method forms an axial limit through the contact between the sphere 809 and the bottom of the first disc 805. When the flow control disc 5 approaches rotation, the second disc 806 will drive the sphere 809 to have a displacement trend relative to the spherical groove 810 of the first disc 805. Since the center of the sphere 809 is below the top plane of the second disc 806, when the flow control disc 5 is subjected to an external torsional force, an inclined contact surface will be generated between the sphere 809 and the spherical groove 810, causing the first disc 805 to receive an upward axial component force. At this time, the third spring 807 is compressed. If the external torque is not sufficient to overcome the resultant force of the elastic force of the third spring 807 and the frictional force of the contact surface, the sphere 809 will be restricted within the spherical groove 810 and cannot slip off, thus realizing self-locking axial limit; when the external torque exceeds the critical value, the sphere 809 will slide out of the current position along the slope of the spherical groove 810 and sequentially embed into adjacent spherical grooves 810 during the continuous rotation of the flow control disc 5, forming a ratchet-type stepped positioning. This design is more adaptable to the axial load working condition compared with the radial limit method, significantly improving the anti-wear ability through stress dispersion of spherical contact. At the same time, the synchronous meshing structure of multiple spheres 809 enhances the limit stability.

[0056] In an embodiment of the present invention, the flow guide cylinder 3 is in a conical shape with a smaller upper part and a larger lower part, so that the flow velocity of the liquid flowing upward in the flow guide cylinder 3 gradually increases, providing sufficient driving force for the flow control disc 5 in some cases with relatively low stirring speeds, enabling the flow control disc 5 to be used normally. In addition, it is also applicable in some reaction kettles 1 with relatively low heights.

[0057] Only some exemplary embodiments of the present invention have been described by way of illustration above. Without doubt, for those of ordinary skill in the art, the described embodiments can be modified in various different ways without departing from the spirit and scope of the present invention. Therefore, the above drawings and descriptions are illustrative in nature and should not be construed as limiting the protection scope of the present invention.

Claims

1. A reactor flow control device for producing methyl isocyanate, comprising a reactor (1), wherein an agitator (2) and a draft tube (3) are arranged in the reactor (1), characterized in that: The reactor (1) is further provided with an atomizer (4) and a flow control disc (5). The flow control disc (5) is arranged above the flow guide tube (3) and has a diameter smaller than the inner diameter of the reactor (1). The flow control disc (5) can move along the axial direction of the reactor (1) to approach or move away from the flow guide tube (3). The flow control disc (5) is provided with a plurality of tapered holes (51) which are larger at the top and smaller at the bottom. When the liquid in the reactor (1) circulates, the liquid in the flow guide tube (3) flows upward and gushes out from the tapered holes (51) of the flow control disc (5), and the gushered liquid contacts and mixes with the atomized droplets sprayed by the atomizer (4).

2. The reactor flow control device for producing methyl isocyanate according to claim 1, characterized in that: The atomizers (4) are provided in a plurality and are distributed in a ring shape along the inner wall of the reaction kettle (1); the nozzles (41) of the atomizers (4) are tilted downwards, and the tilt angle is 15°-30°.

3. The reactor flow control device for producing methyl isocyanate according to claim 1, characterized in that: The flow control disc (5) is in the shape of a cone that bulges upward.

4. The reactor flow control device for producing methyl isocyanate according to claim 1, characterized in that: An elastic member (7) is provided on the top of the flow control disc (5), and the elastic force of the elastic member (7) acts on the flow control disc (5) so that it has a tendency to approach the flow guide cylinder (3).

5. The reactor flow control device for producing methyl isocyanate according to claim 4, characterized in that: The elastic member (7) comprises a fixed seat (71) and a first sleeve (72); the surface of the first sleeve (72) is slidably connected to the inner wall of the fixed seat (71); the bottom of the first sleeve (72) is connected to the flow control disc (5); and a first spring (73) is sleeved on the surface of the first sleeve (72) located between the flow control disc (5) and the fixed seat (71).

6. The reactor flow control device for producing methyl isocyanate according to claim 5, characterized in that: A plurality of guide plates (52) distributed in a circular array are arranged near the circumference of the bottom of the flow control disc (5), and the guide plates (52) are inclined from the inside to the outside of the flow control disc (5).

7. A reactor flow control device for producing methyl isocyanate according to claim 1 or 3, characterized in that: The diameter of the tapered hole (51) on the flow control disc (5) gradually increases from the outside to the inside.

8. The reactor flow control device for producing methyl isocyanate according to claim 5, characterized in that: The elastic member (7) further comprises a limiting assembly (8), wherein the limiting assembly (8) is used to limit the flow control disc (5) from rotating relative to the fixing seat (71).

9. The reactor flow control device for producing methyl isocyanate according to claim 8, characterized in that: The limiting assembly (8) comprises at least one limiting groove (801) formed on the inner wall of the fixing seat (71); the end of the first sleeve (72) is connected to at least one limiting rod (802) in a radially sliding manner; a second spring (803) is provided on one side of the limiting rod (802); the elastic force of the second spring (803) acts on the limiting rod (802) to cause it to have a tendency to move away from the axial direction.

10. The reactor flow control device for producing methyl isocyanate according to claim 1, characterized in that: The guide tube (3) is in a cone shape that is smaller at the top and larger at the bottom.

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