Reactor and isocyanate production process

Abstract

The application provides a reactor and an isocyanate preparation method. The reactor comprises a reaction assembly, the reaction assembly having a reaction cavity; an outer feed nozzle pipe and an inner feed nozzle pipe, the outer feed nozzle pipe being sleeved outside the inner feed nozzle pipe, a feed area being formed between the outer feed nozzle pipe and the inner feed nozzle pipe; the outer feed nozzle pipe and the inner feed nozzle pipe being communicated with the reaction cavity; wherein the reactor has a first feed channel and a second feed channel, the first feed channel and the second feed channel being communicated with the feed area respectively, so that the fluid entering the feed area from the first feed channel and the second feed channel is mixed and then enters the reaction cavity. The reactor provided by the application increases the turbulence degree of the material in the initial section by setting the nozzle structure combined by the outer feed nozzle pipe and the inner feed nozzle pipe, reduces the residence time of the material at the nozzle, and reduces the possibility of solid waste blocking the nozzle.

Description

Technical Field

[0001] This invention relates to the field of isocyanate preparation, and more specifically, to a reactor and a method for preparing isocyanates. Background Technology

[0002] There are several methods for preparing isocyanates, but the most promising is the gas-phase synthesis method. This involves reacting amine vapors with phosgene at high temperatures in an atmosphere of one or more inert substances. After a very short residence time, the reaction product is quenched by rapid cooling, and finally purified to obtain the isocyanate product. This method offers advantages such as high yield, fast reaction speed, and low phosgene retention.

[0003] The existing methods for preparing isocyanates include the following:

[0004] The first preparation method is a gas-phase method for preparing isocyanate reaction heat. The polyhedrin feed pipe is set in the reaction zone, which can use the reaction heat to reduce the droplets entrained in the amine gas, improve the gasification effect, and reduce the generation of impurities during the reaction. However, during the operation, since the polyhedrin feed pipe is in a high-temperature zone, once the amine is heated and coked in the pipe, it will block the pipe and affect the normal progress of the reaction.

[0005] The second preparation method involves a gas-phase reactor and its usage. Amine and phosgene react in a reaction zone, and the resulting high-temperature gas-phase mixture is cooled in a quenching zone. An inert gas purging device is also installed on the inner wall of the reaction zone to purge any solid deposits. This method does not fundamentally reduce the generation of solid byproducts. Periodic shutdowns for purging to remove solid contaminants are difficult to complete and also reduce reaction efficiency.

[0006] The third preparation method involves an isocyanate preparation apparatus where amines and phosgene are mixed and reacted in the impact zone through a nozzle, and then the reaction continues in the extension zone. Simultaneously, a protective gas is introduced along the inner wall of the reactor to reduce side reactions. However, the protective gas film in the impact zone is ineffective, and the deposition of solid contaminants in the impact zone cannot be prevented.

[0007] The fourth preparation method involves a low-temperature gas-phase isocyanate preparation reactor. A rotating shaft and stirring blades are installed inside the reactor. The heat of reaction is removed through stirring and flow under inert gas dilution, reducing side reactions and coking. While this method effectively removes the heat of reaction promptly to prevent heat accumulation, it requires a large amount of relatively cool inert gas for dilution and heat exchange, increasing costs. Furthermore, the presence of multiple blades within the reaction zone increases the contact area between the material and the wall, making it easier for solid contaminants to accumulate. Summary of the Invention

[0008] The main objective of this invention is to provide a reactor and a method for preparing isocyanates, in order to solve the problem that existing isocyanate preparation devices are prone to accumulating fixed pollutants.

[0009] To achieve the above objectives, according to one aspect of the present invention, a reactor is provided, comprising: a reaction assembly having a reaction chamber; an outer feed nozzle and an inner feed nozzle, the outer feed nozzle being sleeved outside the inner feed nozzle, forming a feed region between the outer feed nozzle and the inner feed nozzle; both the outer feed nozzle and the inner feed nozzle being in communication with the reaction chamber; wherein the reactor has a first feed channel and a second feed channel, the first feed channel and the second feed channel being respectively in communication with the feed region, so that fluids entering the feed region through the first feed channel and the second feed channel are mixed and then enter the reaction chamber.

[0010] Furthermore, the reactor also includes: a first feed pipe, the cavity of which forms a first feed channel; and a second feed pipe, which is connected to the second feed channel; wherein the first feed pipe is located at the bottom of the external feed nozzle pipe, and the second feed pipe is located at the top of the reaction assembly.

[0011] Furthermore, the reaction assembly includes an inner reaction tube and an outer reaction tube, with the outer reaction tube sleeved on the outside of the inner reaction tube, and the gap between the inner and outer reaction tubes forming a second feed channel; wherein, the outer feed nozzle tube has a first clearance opening on its wall that communicates with the second feed channel.

[0012] Furthermore, both the inner and outer reaction tubes have through holes at their bottoms that communicate with the reaction chamber, and the outer feed nozzle passes through these through holes to communicate with the reaction chamber.

[0013] Furthermore, the reactor also includes a distribution component, which is installed at the bottom of the inner reaction tube and is connected to the second feed channel and the feed area respectively.

[0014] Furthermore, the distribution assembly includes an outer distribution pipe and an inner distribution pipe. The outer distribution pipe is sleeved on the outside of the inner distribution pipe, and the gap between the outer distribution pipe and the inner distribution pipe forms a mixing space. The upper opening of the mixing space is connected to the second feed channel. The outer feed nozzle pipe passes through the inner distribution pipe, and the inner distribution pipe is provided with a second clearance opening opposite to the first clearance opening.

[0015] Furthermore, the distribution component also includes: multiple segmented plates, which are disposed within the mixing space and spaced apart around the inner distribution pipe; wherein each segmented plate is a trapezoidal plate, with its long side connected to the inner distribution pipe and its short side connected to the outer distribution pipe.

[0016] Furthermore, the bottom of the outer reaction tube has a first bottom wall portion, which is connected to the outer feed nozzle tube; the bottom of the inner reaction tube has a second bottom wall portion, which is connected to the outer feed nozzle tube; the first bottom wall portion and the second bottom wall portion are spaced apart, and a distribution assembly is disposed between the first bottom wall portion and the second bottom wall portion; and / or, the outer feed nozzle tube has a first extension section, and the distribution assembly is disposed around the first extension section, with the height of the distribution assembly being 0.7 to 1 times the axial length of the first extension section.

[0017] Furthermore, the reactor also includes: a first support component, an external feed nozzle pipe inserted into the reaction chamber, the first support component being sandwiched between the external feed nozzle pipe and the inner wall of the reaction chamber; and / or, a second support component, the reaction assembly including an inner reaction tube and an outer reaction tube nested together, the gap between the inner reaction tube and the outer reaction tube forming a second feed channel, the second support component being sandwiched between the inner reaction tube and the outer reaction tube.

[0018] Furthermore, along the flow direction of the fluid inside the external feed nozzle pipe, the external feed nozzle pipe includes a first outer pipe section, a second outer pipe section, and a third outer pipe section. The flow cross sections of the first, second, and third outer pipe sections are all circular, and the ratio between the maximum diameter of the first, second, and third outer pipe sections is 1:0.3–0.7:1–1.3; and / or, along the flow direction of the fluid inside the internal feed nozzle pipe, the internal feed nozzle pipe includes a first inner pipe section, a second inner pipe section, and a third inner pipe section. The flow cross sections of the first, second, and third inner pipe sections are all circular, and the ratio between the maximum diameter of the first, second, and third inner pipe sections is 1:0.1–0.5:0.5–0.8.

[0019] Furthermore, along the flow direction of the fluid inside the external feed nozzle pipe, the external feed nozzle pipe includes a first outer pipe section, a second outer pipe section, and a third outer pipe section, all of which have circular flow cross sections. Along the flow direction of the fluid inside the internal feed nozzle pipe, the internal feed nozzle pipe includes a first inner pipe section, a second inner pipe section, and a third inner pipe section, all of which have circular flow cross sections. The ratio of the maximum diameter of the first outer pipe section to the maximum diameter of the first inner pipe section is 1:1.2 to 1.5; and / or, the ratio of the maximum diameter of the second outer pipe section to the maximum diameter of the second inner pipe section is 1:1.2 to 1.5; and / or, the ratio of the maximum diameter of the third outer pipe section to the maximum diameter of the third inner pipe section is 1:1.2 to 1.5.

[0020] Furthermore, both the outer wall of the reaction assembly and the inner wall of the reaction chamber are cylindrical, and the ratio between the outer wall of the reaction assembly and the inner wall of the reaction chamber is 1:0.8 to 0.98; and / or, the external feed nozzle has a first contraction section, the contraction cone angle of which ranges from 15° to 30°; and / or, the internal feed nozzle has a second contraction section, the contraction cone angle of which ranges from 15° to 30°; and / or, the external feed nozzle has a first extension section, the extension cone angle of which ranges from 15° to 30°; and / or, the external feed nozzle has a second extension section, the extension cone angle of which ranges from 15° to 30°.

[0021] According to another aspect of the present invention, a method for preparing isocyanate is provided, applicable to the reactor in any of the foregoing technical solutions. The method for preparing isocyanate includes: introducing an inert gas into a first feed channel of the reactor, introducing an amine stream comprising amine vapor and a protective gas into a second feed channel of the reactor, and introducing a phosgene stream into an inner feed nozzle; wherein the amine in the amine vapor is one of 1,4-butanediamine, 1,6-hexanediamine, m-phenylenedimethyldiamine, and toluenediamine.

[0022] Furthermore, the feed molar ratio of amine in the amine vapor to phosgene in the phosgene stream is 1:2 to 10; and / or, the feed molar ratio of amine in the amine vapor to inert gas is 1:0.3 to 3.

[0023] Furthermore, the isocyanate preparation method further includes: heating the inert gas to 250°C to 500°C before introducing the inert gas into the first feed channel of the reactor; and / or heating the amine in the amine stream to 80°C to 350°C before introducing the amine stream into the second feed channel of the reactor; and / or heating the phosgene in the phosgene stream to 300°C to 500°C before introducing the phosgene stream into the inner feed nozzle pipe.

[0024] By employing the technical solution of this invention, an internal and external nozzle structure combining an external feed nozzle pipe and an internal feed nozzle pipe is adopted. This increases the turbulence of the material in the initial stage, reduces the residence time of the material at the nozzle, and reduces the possibility of solid waste clogging the nozzle. By setting up the first and second feed channels, the amine is fed countercurrently through the outer wall of the reactor, which can make full use of the reaction heat to improve the degree of amine vaporization. While effectively utilizing the waste heat of the reaction, the lower wall temperature in the reaction zone also reduces the enrichment of solid impurities on the wall surface, reduces the reactor cleaning cycle, and effectively reduces operating costs. Attached Figure Description

[0025] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0026] Figure 1 A schematic diagram of the reactor according to the present invention is shown;

[0027] Figure 2 It shows Figure 1 A magnified view of a portion of the reactor;

[0028] Figure 3 It shows Figure 1 A first-view structural schematic diagram of the distributed components of the reactor located in the region between CD; and

[0029] Figure 4 A second-view structural schematic diagram of the distribution assembly of the reactor according to the present invention is shown.

[0030] The above figures include the following reference numerals:

[0031] 100. Reactor; 1. Reaction assembly; 11. Reaction chamber; 12. Inner reaction tube; 121. Second bottom wall; 13. Outer reaction tube; 131. First bottom wall; 2. Outer feed nozzle; 22. First outer tube section; 23. First contraction section; 24. Second outer tube section; 25. First expansion section; 26. Third outer tube section; 3. Inner feed nozzle; 32. First inner tube section; 33. Second contraction section; 34. Second inner tube section; 35. Second expansion section; 36. Third inner tube section; 4. Feeding area; 5. First feed channel; 6. Second feed channel; 7. First feed pipe; 8. Second feed pipe; 9. Distribution assembly; 91. Outer distribution pipe; 92. Inner distribution pipe; 93. Mixing space; 94. Divider; 20. First support component; 30. Second support component. Detailed Implementation

[0032] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0033] This invention provides a reactor, such as Figures 1 to 4 As shown, the reactor includes a reaction assembly 1, an external feed nozzle 2, and an internal feed nozzle 3. The reaction assembly 1 has a reaction chamber 11. The external feed nozzle 2 is sleeved on the outside of the internal feed nozzle 3, and a feeding area 4 is formed between the external feed nozzle 2 and the internal feed nozzle 3. Both the external feed nozzle 2 and the internal feed nozzle 3 are connected to the reaction chamber 11. The reactor 100 also has a first feed channel 5 and a second feed channel 6, which are respectively connected to the feeding area 4 so that the fluids entering the feeding area 4 through the first feed channel 5 and the second feed channel 6 are mixed and then enter the reaction chamber 11.

[0034] With this structural configuration, the material enters the reaction chamber 11 through the annular feeding space formed between the external feed nozzle 2 and the internal feed nozzle 3. The annular feeding channel increases the turbulence of the material in the initial section, reduces the feeding time, and lowers the probability of high-temperature coking and blockage affecting the feeding. Furthermore, the fluids entering the feeding area 4 through the first feed channel 5 and the second feed channel 6 mix before entering the reaction chamber 11. In this way, the mixed gas is ejected through the nozzle diffusion section with a high degree of turbulence and reacts with the phosgene P entering through the internal feed nozzle 3 in the reaction diffusion zone. The residence time of the reactants at the nozzle is extremely short, thereby effectively reducing the probability of coking and blockage at the nozzle, thus solving the problem of easy accumulation of fixed pollutants in the existing isocyanate preparation device.

[0035] Furthermore, the reactor 100 also includes a first feed pipe 7 and a second feed pipe 8, wherein the first feed pipe 7 is disposed at the bottom of the external feed nozzle pipe 2, and the cavity of the first feed pipe 7 forms a first feed channel 5; the second feed pipe 8 is disposed at the top of the reaction assembly 1, so that inert gas N is fed through the first feed pipe 7 located at the bottom of the external feed nozzle pipe 2, and amine A is fed through the second feed pipe 8 located at the top of the reaction assembly 1.

[0036] Specifically, the reaction assembly 1 consists of an inner reaction tube 12 and an outer reaction tube 13; wherein, the outer reaction tube 13 is sleeved on the outside of the inner reaction tube 12, and the gap between the inner reaction tube 12 and the outer reaction tube 13 forms a second feed channel 6; the outer feed nozzle tube 2 has a first clearance opening on its tube wall that communicates with the second feed channel 6.

[0037] To ensure thorough mixing of materials, both the inner reaction tube 12 and the outer reaction tube 13 have through holes at their bottoms that communicate with the reaction chamber 11. The outer feed nozzle 2 passes through these through holes to connect with the reaction chamber 11, thereby enabling the mixing of fluids entering the feed area 4 through the first feed channel 5 and the second feed channel 6. This structural arrangement allows the amine to be fed countercurrently through the outer wall of the inner reaction tube 12, fully utilizing the heat of reaction to increase the degree of amine vaporization. While effectively utilizing the waste heat of the reaction, the lower wall temperature within the reaction zone also reduces the accumulation of solid impurities on the wall surface, thus shortening the reactor cleaning cycle.

[0038] Furthermore, the reactor 100 also includes a distribution component 9, which is installed at the bottom of the inner reaction tube 12 and is connected to the second feed channel 6 and the feed area 4 respectively, so that the material enters the distribution component for distribution before entering the feed area 4 through the second feed channel 6.

[0039] Specifically, the distribution component 9 includes an outer distribution pipe 91 and an inner distribution pipe 92. The outer distribution pipe 91 is sleeved on the outside of the inner distribution pipe 92. The gap between the outer distribution pipe 91 and the inner distribution pipe 92 forms a mixing space 93. The upper opening of the mixing space 93 is connected to the second feed channel 6. The outer feed nozzle pipe 2 passes through the inner distribution pipe 92. The inner distribution pipe 92 is provided with a second clearance opening opposite to the first clearance opening, so that the material enters the mixing space 93 through the second feed channel 6, thereby realizing the redistribution of the material.

[0040] To ensure effective mixing or redistribution of materials, the distribution assembly 9 further includes multiple dividing plates 94. These dividing plates 94 are disposed within the mixing space 93 and spaced apart around the inner distribution pipe 92. Preferably, 4-16 dividing plates 94 are provided, each of which can be a trapezoidal plate. The long side of each dividing plate 94 is connected to the inner distribution pipe 92, forming the edge of the diffuser section of the outer feed nozzle pipe 2, while the short side of each dividing plate 94 is connected to the outer distribution pipe 91. With this structural arrangement, the amine stream enters the mixing space 93 after entering from the second feed channel 6. After being redistributed by the distribution assembly 9, it enters the reaction chamber 11 through the outer feed nozzle pipe 2. Simultaneously, the inert gas stream enters the reaction assembly 1 from the first feed channel 5. Inside the distribution assembly 9, it mixes with the amine stream or undergoes single-stream redistribution before entering the reaction chamber 11 through the outer feed nozzle pipe 2.

[0041] The function of the segment 94 in the distribution component 9 is as follows:

[0042] (1) Divide the amine stream into smaller portions to enhance mass transfer;

[0043] (2) Increase the turbulence of materials and play a role in turbulence;

[0044] (3) Make the amine stream at the outlet of the inner feed pipe have a relatively uniform circumferential distribution.

[0045] The outer reaction tube 13 has a first bottom wall 131 at its bottom, which is connected to the outer feed nozzle tube 2; the inner reaction tube 12 has a second bottom wall 121 at its bottom, which is also connected to the outer feed nozzle tube 2; the first bottom wall 131 and the second bottom wall 121 are spaced apart, and the distribution component 9 is disposed between the first bottom wall 131 and the second bottom wall 121; the sleeve-shaped structure facilitates the installation of the distribution component 9 and also facilitates subsequent disassembly and maintenance.

[0046] To enhance the stability of reactor 100, reactor 100 also includes a first support component 20 and a second support component 30. The first support component 20 is sandwiched between the external feed nozzle pipe 2 and the inner wall of the reaction chamber 11, thereby ensuring the secure insertion of the external feed nozzle pipe 2 within the reaction chamber 11. The second support component 30 is sandwiched within the second feed channel 6 between the inner reaction tube 12 and the outer reaction tube 13, thereby ensuring the stability of the inner reaction tube 12 during the reaction process. The first support component 20 is a solid filler, filling the low-temperature zone to prevent material from entering.

[0047] To improve the material feeding speed and enhance the mixing effect, the external feed nozzle 2 and the internal feed nozzle 3 are arranged in the form of Venturi tubes. Specifically, along the flow direction of the fluid in the external feed nozzle 2, the external feed nozzle 2 includes a first outer pipe section 22, a second outer pipe section 24, and a third outer pipe section 26. The flow cross-sections of the first outer pipe section 22, the second outer pipe section 24, and the third outer pipe section 26 are all circular. The ratio between the maximum diameter of the first outer pipe section 22, the maximum diameter of the second outer pipe section 24, and the maximum diameter of the third outer pipe section 26 is preferably 1:0.3~0.7:1~1.3. The external feed nozzle 2 also has a first contraction section 23 and a first expansion section 25. The contraction cone angle of the first contraction section 23 is preferably in the range of 15° to 30°, and the expansion cone angle of the first expansion section 25 is preferably in the range of 15° to 30°.

[0048] Accordingly, along the flow direction of the fluid within the inner feed nozzle pipe 3, the inner feed nozzle pipe 3 includes a first inner pipe section 32, a second inner pipe section 34, and a third inner pipe section 36. The flow cross-sections of the first inner pipe section 32, the second inner pipe section 34, and the third inner pipe section 36 are all circular. The ratio between the maximum diameters of the first inner pipe section 32, the second inner pipe section 34, and the third inner pipe section 36 is 1:0.1–0.5:0.5–0.8. The inner feed nozzle pipe 3 also has a second contraction section 33 and a second expansion section 35. The contraction cone angle of the second contraction section 33 ranges from 15° to 30°, and the expansion cone angle of the second expansion section 35 also ranges from 15° to 30°. This structural arrangement increases the flow velocity of the material in the diffusion section and shortens the residence time of the material at the nozzle, which helps to reduce the probability of coking and clogging at the nozzle.

[0049] To ensure the feeding stability of the annular space formed between the external feed nozzle pipe 2 and the internal feed nozzle pipe 3, the ratio between the maximum diameter of the first external pipe section 22 and the maximum diameter of the first internal pipe section 32 is preferably 1:1.2 to 1.5; and / or, the ratio between the maximum diameter of the second external pipe section 24 and the maximum diameter of the second internal pipe section 34 is preferably 1:1.2 to 1.5; and / or, the ratio between the maximum diameter of the third external pipe section 26 and the maximum diameter of the third internal pipe section 36 is preferably 1:1.2 to 1.5.

[0050] In some embodiments, the distribution component 9 is disposed around the first extension segment 25, and the height of the distribution component 9 is 0.7 to 1 times the axial length of the first extension segment 25; the outer wall surface of the reaction component 1 and the inner wall surface of the reaction chamber 11 are both cylindrical, and the ratio between the outer wall surface of the reaction component 1 and the inner wall surface of the reaction chamber 11 is 1:0.8 to 0.98.

[0051] In the reactor provided by this embodiment of the invention, amine is fed countercurrently through a second feed channel 6 formed on the outer wall of the inner reaction tube 12. This fully utilizes the heat of reaction to increase the degree of amine vaporization. While effectively utilizing the waste heat of the reaction, the lower wall temperature in the reaction zone also reduces the accumulation of solid impurities on the wall surface, reducing the reactor cleaning cycle. Inert gas enters the reaction assembly 1 through the first feed channel 5, is fed from the inlet section of the outer feed nozzle pipe 2, passes through the nozzle constriction section and throat, and enters the distribution assembly 9, where it undergoes impact mixing with the amine gas inside the mixing space 93. The mixed gas is ejected through the nozzle diffuser section with a high degree of turbulence and reacts with the phosgene P that enters through the inner feed nozzle pipe 3 in the reaction diffusion zone. The reactants have a very short residence time at the nozzle, which effectively reduces the probability of coking and clogging at the nozzle. The heat released by the reaction in the reaction diffusion zone is exchanged with the inner wall, which further vaporizes the droplets in the amine stream that have not been completely vaporized. While effectively utilizing the heat of reaction, it also reduces the situation where the reaction effect is deteriorated due to the entrainment of amine droplets. The lower wall temperature can also reduce the generation and adhesion of solid impurities on the inner wall.

[0052] In another aspect, the present invention provides a method for preparing isocyanate, applicable to the reactor in any of the above-described technical solutions, wherein the method for preparing isocyanate includes: introducing an inert gas into a first feed channel 5 of the reactor 100, introducing an amine stream comprising amine vapor and a protective gas into a second feed channel 6 of the reactor 100, and introducing a phosphor stream into an inner feed nozzle pipe 3; wherein the amine in the amine vapor is one of 1,4-butanediamine, 1,6-hexanediamine, m-phenylenedimethyldiamine, and toluenediamine.

[0053] Specifically, the feed molar ratio of amine in amine vapor to phosgene in phosgene stream is 1:2 to 10, preferably 1:3 to 6; the feed molar ratio of amine in amine vapor to inert gas is 1:0.3 to 3, preferably 1:0.6 to 1.0.

[0054] Furthermore, the isocyanate preparation method further includes: heating the inert gas to 250°C to 500°C before introducing the inert gas into the first feed channel 5 of the reactor 100; heating the amine in the amine stream to 80°C to 350°C before introducing the amine stream into the second feed channel 6 of the reactor 100; and heating the phosgene in the phosgene stream to 300°C to 500°C before introducing the phosgene stream into the inner feed nozzle pipe 3.

[0055] As can be seen from the above description, the above embodiments of the present invention achieve the following technical effects: the combination of the external feed nozzle pipe 2 and the internal feed nozzle pipe 3 into an internal and external nozzle structure increases the turbulence of the material in the initial section, reduces the residence time of the material at the nozzle, and reduces the possibility of solid waste clogging the nozzle; by setting the first and second feed channels, the amine is fed countercurrently through the outer wall of the reactor, which can make full use of the reaction heat to improve the degree of amine vaporization. While effectively utilizing the reaction waste heat, the lower wall temperature in the reaction zone also reduces the enrichment of solid impurities on the wall surface, reduces the reactor cleaning cycle, and effectively reduces operating costs.

[0056] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A reactor, characterized in that, include: The reaction assembly (1) has a reaction chamber (11). An external feed nozzle (2) and an internal feed nozzle (3) are provided. The external feed nozzle (2) is sleeved on the outside of the internal feed nozzle (3). A feeding area (4) is formed between the external feed nozzle (2) and the internal feed nozzle (3). Both the external feed nozzle (2) and the internal feed nozzle (3) are connected to the reaction chamber (11). The reactor (100) has a first feed channel (5) and a second feed channel (6), which are respectively connected to the feed area (4) so ​​that the fluids entering the feed area (4) through the first feed channel (5) and the second feed channel (6) are mixed and then enter the reaction chamber (11). The first feed pipe (7) has a cavity that forms the first feed channel (5). The second feed pipe (8) is connected to the second feed channel (6); The first feed pipe (7) is located at the bottom of the external feed nozzle pipe (2), and the second feed pipe (8) is located at the top of the reaction assembly (1). The reaction assembly (1) includes an inner reaction tube (12) and an outer reaction tube (13). The outer reaction tube (13) is sleeved on the outside of the inner reaction tube (12), and the gap between the inner reaction tube (12) and the outer reaction tube (13) forms the second feed channel (6). The external feed nozzle pipe (2) has a first clearance opening on its pipe wall that communicates with the second feed channel (6); Distribution component (9) is installed at the bottom of the inner reaction tube (12) and is connected to the second feed channel (6) and the feed area (4) respectively; The distribution assembly (9) includes an outer distribution tube (91) and an inner distribution tube (92). The outer distribution tube (91) is sleeved on the outside of the inner distribution tube (92). The gap between the outer distribution tube (91) and the inner distribution tube (92) forms a mixing space (93). The upper opening of the mixing space (93) is connected to the second feed channel (6). The outer feed nozzle tube (2) passes through the inner distribution tube (92). The inner distribution tube (92) is provided with a second clearance opening opposite to the first clearance opening.

2. The reactor according to claim 1, characterized in that, The bottom of both the inner reaction tube (12) and the outer reaction tube (13) is provided with a through hole that communicates with the reaction chamber (11). The outer feed nozzle tube (2) passes through the through hole to communicate with the reaction chamber (11).

3. The reactor according to claim 1, characterized in that, The distribution component (9) also includes: Multiple segmented pieces (94) are disposed within the mixing space (93) and spaced apart around the inner distribution tube (92); Each of the segmented pieces (94) is a trapezoidal plate, with the long side of the segmented piece (94) connected to the inner distribution pipe (92) and the short side of the segmented piece (94) connected to the outer distribution pipe (91).

4. The reactor according to claim 1, characterized in that, The bottom of the outer reaction tube (13) has a first bottom wall portion (131), which is connected to the outer feed nozzle tube (2); the bottom of the inner reaction tube (12) has a second bottom wall portion (121), which is connected to the outer feed nozzle tube (2); the first bottom wall portion (131) and the second bottom wall portion (121) are spaced apart, and the distribution component (9) is disposed between the first bottom wall portion (131) and the second bottom wall portion (121); and / or The external feed nozzle pipe (2) has a first extension section (25), and the distribution component (9) is arranged around the first extension section (25), the height of the distribution component (9) being 0.7 to 1 times the axial length of the first extension section (25).

5. The reactor according to claim 1, characterized in that, The reactor also includes: A first support component (20) is provided, wherein the external feed nozzle pipe (2) is inserted into the reaction chamber (11), and the first support component (20) is sandwiched between the external feed nozzle pipe (2) and the inner wall of the reaction chamber (11); and / or The second support component (30) is provided. The reaction assembly (1) includes an inner reaction tube (12) and an outer reaction tube (13) that are nested together. The gap between the inner reaction tube (12) and the outer reaction tube (13) forms the second feed channel (6). The second support component (30) is sandwiched between the inner reaction tube (12) and the outer reaction tube (13).

6. The reactor according to any one of claims 1 to 5, characterized in that, Along the flow direction of the fluid inside the external feed nozzle pipe (2), the external feed nozzle pipe (2) includes a first outer pipe section (22), a second outer pipe section (24), and a third outer pipe section (26). The flow cross sections of the first outer pipe section (22), the second outer pipe section (24), and the third outer pipe section (26) are all circular. The ratio between the maximum diameter of the first outer pipe section (22), the maximum diameter of the second outer pipe section (24), and the maximum diameter of the third outer pipe section (26) is 1:0.3~0.7:1~1.3; and / or Along the flow direction of the fluid inside the inner feed nozzle pipe (3), the inner feed nozzle pipe (3) includes a first inner pipe section (32), a second inner pipe section (34), and a third inner pipe section (36). The flow cross sections of the first inner pipe section (32), the second inner pipe section (34), and the third inner pipe section (36) are all circular. The ratio between the maximum diameter of the first inner pipe section (32), the maximum diameter of the second inner pipe section (34), and the maximum diameter of the third inner pipe section (36) is 1:0.1~0.5:0.5~0.

8.

7. The reactor according to any one of claims 1 to 5, characterized in that, Along the flow direction of the fluid inside the external feed nozzle pipe (2), the external feed nozzle pipe (2) includes a first external pipe section (22), a second external pipe section (24) and a third external pipe section (26), and the flow cross sections of the first external pipe section (22), the second external pipe section (24) and the third external pipe section (26) are all circular; Along the flow direction of the fluid inside the inner feed nozzle pipe (3), the inner feed nozzle pipe (3) includes a first inner pipe section (32), a second inner pipe section (34) and a third inner pipe section (36), and the flow cross sections of the first inner pipe section (32), the second inner pipe section (34) and the third inner pipe section (36) are all circular; in, The ratio between the maximum diameter of the first outer pipe section (22) and the maximum diameter of the first inner pipe section (32) is 1:1.2~1.5; and / or The ratio between the maximum diameter of the second outer pipe section (24) and the maximum diameter of the second inner pipe section (34) is 1:1.2~1.5; and / or The ratio between the maximum diameter of the third outer pipe section (26) and the maximum diameter of the third inner pipe section (36) is 1:1.2~1.

5.

8. The reactor according to any one of claims 1 to 5, characterized in that, The outer wall of the reaction assembly (1) and the inner wall of the reaction chamber (11) are both cylindrical, and the ratio between the outer wall of the reaction assembly (1) and the inner wall of the reaction chamber (11) is 1:0.8~0.98; and / or The external feed nozzle pipe (2) has a first contraction section (23), the contraction cone angle of which ranges from 15° to 30°; and / or The internal feed nozzle pipe (3) has a second contraction section (33), the contraction cone angle of which ranges from 15° to 30°; and / or The external feed nozzle pipe (2) has a first extension section (25), the extension cone angle of which ranges from 15° to 30°; and / or The internal feed nozzle tube (3) has a second extension section (35), and the extension cone angle of the second extension section (35) ranges from 15° to 30°.

9. A method for preparing isocyanate, characterized in that, The isocyanate preparation method using the reactor described in any one of claims 1 to 8 comprises: An inert gas is introduced into the first feed channel (5) of the reactor (100), an amine stream including amine vapor and protective gas is introduced into the second feed channel (6) of the reactor (100), and a light stream is introduced into the inner feed nozzle pipe (3). The amine in the amine vapor is one of 1,4-butanediamine, 1,6-hexanediamine, m-phenylenedimethyldiamine, and toluenediamine.

10. The method for preparing isocyanate according to claim 9, characterized in that, The feed molar ratio of the amine in the amine vapor to the phosgene in the phosgene stream is 1:2~10; and / or The feed molar ratio of the amine in the amine vapor to the inert gas is 1:0.3~3.

11. The method for preparing isocyanate according to claim 9, characterized in that, The isocyanate preparation method further includes: Before introducing inert gas into the first feed channel (5) of the reactor (100), the inert gas is heated to 250°C to 500°C; and / or Before introducing the amine stream into the second feed channel (6) of the reactor (100), the amine in the amine stream is heated to 80°C to 350°C; and / or Before introducing the phosgene into the internal feed nozzle tube (3), the phosgene in the phosgene is heated to 300°C to 500°C.

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