A mixing system for the hydrocyanation of adiponitrile

Abstract

The application relates to the field of adiponitrile production, and particularly discloses a mixing system for hydrocyanation of adiponitrile, which comprises a dynamic mixer and a reaction kettle, the dynamic mixer comprises three groups of first, second and third dynamic mixers, the three-stage dynamic mixer can effectively improve the mixing efficiency, realizes liquid-phase dynamic mixing feeding, the system reduces the concentration of hydrocyanic acid through 3PN dispersion, can reduce the concentration of hydrocyanic acid in the mixing process of reactants, reduces the chance of direct contact between high-concentration hydrocyanic acid and the catalyst, and can effectively avoid catalyst poisoning and deactivation.

Description

Technical Field

[0001] This invention relates to the adiponitrile production industry, and particularly to a mixing system for the hydrocyanation of adiponitrile. Background Technology

[0002] The liquid hydrogen cyanide used in the adiponitrile hydrocyanation process is extremely prone to polymerization under alkaline, high temperature, long-term storage, and exposure to light, radiation, discharge, and electrolysis conditions.

[0003] Existing mixing systems typically use a single-stage mixer to directly mix hydrogen cyanide with the catalyst. This is a simple dynamic single-stage mixing process. When the concentration of hydrogen cyanide is too high, a large amount of hydrogen cyanide directly contacting the catalyst can easily lead to catalyst poisoning. Summary of the Invention

[0004] This invention provides a mixing system for the hydrocyanation of adiponitrile, to solve the technical problem in the prior art that catalyst poisoning is easily caused when a large amount of hydrocyanic acid comes into direct contact with the catalyst.

[0005] To solve the above problems, the present invention provides a mixing system for the hydrocyanation of adiponitrile, which adopts the following technical solution: it includes a dynamic mixer and a reaction vessel. The dynamic mixer includes three sets, namely a first dynamic mixer, a second dynamic mixer and a third dynamic mixer. The dynamic mixer is provided with a first inlet, a second inlet and a discharge outlet. The reaction vessel is provided with a reflux outlet, a first outlet, a second outlet and a third outlet.

[0006] Liquid hydrogen cyanide is introduced into the first inlet of the first dynamic mixer, 3PN is introduced into the second inlet of the first dynamic mixer, the discharge port on the first dynamic mixer is connected to the first inlet on the second dynamic mixer, the catalyst is introduced into the second inlet of the second dynamic mixer, and the discharge port on the second dynamic mixer is connected to the first inlet on the third dynamic mixer. The second inlet of the third dynamic mixer is connected to the second outlet. The discharge port and the reflux port of the third dynamic mixer are connected by a first reflux pipe. A first heat exchanger is installed on the first reflux pipe. The discharge port and the reflux port of the third dynamic mixer are connected through the first reflux pipe. The first outlet is connected to the next stage reactor. The third outlet is connected to the distillation column.

[0007] Furthermore, the reactor includes two sets, namely a first reactor and a second reactor. The second reactor is provided with a series inlet. The first outlet of the first reactor is connected to the series inlet of the second reactor. The second outlet of the first reactor is connected to the second inlet of the third dynamic mixer. The discharge port of the third dynamic mixer is connected to the reflux port of the first reactor through a first reflux pipe. A second reflux pipe is connected between the second outlet of the second reactor and the series inlet. A second heat exchanger is provided on the second reflux pipe.

[0008] Furthermore, the flow rate of liquid hydrogen cyanide is set to am³ / h, the flow rate of 3PN is set to bm³ / h, the flow rate of catalyst is set to cm³ / h, a:b:c is 1:5:5, the flow rate of the first inlet on the second dynamic mixer is (a+b) m³ / h, and the flow rate of the first inlet on the third dynamic mixer is (a+b+c) m³ / h.

[0009] Furthermore, the dynamic mixer includes a stirring assembly and a mixing chamber. The first feed inlet, the second feed inlet, and the discharge outlet are all connected to the mixing chamber. A baffle plate is installed inside the mixing chamber at the discharge outlet. The baffle plate includes a connecting part and a flow-blocking part. The connecting part is fixedly connected to the inside of the mixing chamber. A first gap is provided between the flow-blocking part and the inner wall of the mixing chamber. Based on the bottom end face of the mixing chamber, the height of the flow-blocking part is higher than the height of the discharge outlet. A baffle is installed inside the mixing chamber. A second gap is provided between the baffle and the inner wall of the mixing chamber.

[0010] Furthermore, the mixing chamber includes a mixing section and a stacking section. The bottom end face of the stacking section is set as an arc surface structure. The first feed port, the second feed port, and the discharge port are all connected to the mixing section. The bottom end face of the baffle is flush with the bottom end face of the mixing section.

[0011] Furthermore, the maximum inner diameter of the mixing chamber is set to φ, the height of the mixing section is set to H1, the height of the accumulation section is set to H2, the height of the mixing chamber is set to H3, H3=H1+H2, φ:H1 is 1:(1-1.5), φ:H2 is 1:(0.2-0.4), the width of the baffle is set to W1, the height of the baffle is set to H4, φ:W1 is 1:(0.05-0.1), H4:H1 is 1:(1-1.5), and the width of the second gap is set to W2, φ:W2 is 1:(0.01-0.03).

[0012] Furthermore, φ:H1 is 1:1.25, φ:H2 is 1:0.3125, φ:W1 is 1:0.075, H4:H1 is 1:1.25, and φ:W2 is 1:0.025.

[0013] Furthermore, the stirring assembly includes a stirring shaft and stirring blades. The stirring blades are divided into two sets, which are respectively distributed in the middle of the mixing section and at the connection between the mixing section and the accumulation section. The diameter of the stirring shaft is set to D1, the maximum outer diameter of the stirring blades is set to D2, and the distance between the two sets of stirring blades is set to H5. The ratio of φ:D1 is 1:(0.1-0.2), the ratio of φ:D2 is 1:(0.3-0.8), and the ratio of H5:H1 is 1:(2-3).

[0014] Furthermore, φ:D1 is 1:0.1125, φ:D2 is 1:0.5, and H5:H1 is 1:2.5.

[0015] Furthermore, the dynamic mixer is equipped with a frequency converter for driving the stirring shaft to rotate, and a cooler is installed on the frequency converter, which is located between the mixing chamber and the frequency converter.

[0016] The beneficial effects of the mixing system for adiponitrile hydrocyanation provided by the present invention are as follows: the three-stage dynamic mixer connected in series can effectively improve the mixing efficiency, realize dynamic liquid-phase mixing and feeding, and the system can reduce the concentration of hydrocyanic acid by dispersing through 3PN, which can reduce the concentration of hydrocyanic acid in the reactants during the mixing process, reduce the chance of high concentration of hydrocyanic acid directly contacting the catalyst, and effectively avoid catalyst poisoning and deactivation. Attached Figure Description

[0017] The above and other objects, features, and advantages of exemplary embodiments of the present invention will become readily apparent from the following detailed description taken in conjunction with the accompanying drawings. In the drawings, several embodiments of the invention are illustrated by way of example and not limitation, and like or corresponding reference numerals denote like or corresponding parts, wherein: Figure 1 This is a schematic diagram of a mixing system for the hydrocyanation of adiponitrile according to the present invention; Figure 2 This is a schematic diagram of a dynamic mixer structure for a mixing system of adiponitrile hydrocyanation according to the present invention. Figure 1 ; Figure 3 This is a schematic diagram of a dynamic mixer structure for a mixing system of adiponitrile hydrocyanation according to the present invention. Figure 2 .

[0018] Explanation of reference numerals in the attached figures: 1. Dynamic mixer; 11. First dynamic mixer; 12. Second dynamic mixer; 13. Third dynamic mixer; 14. First feed inlet; 15. Second feed inlet; 16. Discharge port; 17. First reflux pipe; 171. First heat exchanger; 18. Stirring assembly; 181. Stirring shaft; 182. Stirring blades; 19. Mixing chamber; 191. Baffle plate; 1911. Connecting part; 1912. Baffle part; 19 13. First gap; 192. Baffle; 1921. Second gap; 193. Mixing section; 194. Stacking section; 10. Frequency converter; 101. Cooler; 2. Reactor; 21. Reflux port; 23. First discharge port; 24. Second discharge port; 25. Third discharge port; 26. First reactor; 27. Second reactor; 271. Series inlet; 272. Second reflux pipe; 2721. Second heat exchanger. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Those skilled in the art should understand that the embodiments described below are only some, not all, of the embodiments disclosed. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0020] The number of any elements in the accompanying drawings is for illustrative purposes only and not as a limitation, and any naming is for distinction only and has no limiting meaning.

[0021] The principles and spirit of the present invention will be explained in detail below with reference to several representative embodiments.

[0022] The present invention provides a mixing system for the hydrocyanation of adiponitrile, such as... Figures 1 to 3 As shown, the system includes a dynamic mixer 1 and a reactor 2. The dynamic mixer 1 includes three sets of components, namely a first dynamic mixer 11, a second dynamic mixer 12, and a third dynamic mixer 13. The dynamic mixer 1 is provided with a first feed inlet 14, a second feed inlet 15, and a discharge outlet 16. The reactor 2 is provided with a reflux outlet 21, a first discharge outlet 23, a second discharge outlet 24, and a third discharge outlet 25. Liquid hydrogen cyanide is introduced into the first inlet 14 of the first dynamic mixer 11, 3PN is introduced into the second inlet 15 of the first dynamic mixer 11, the discharge port 16 on the first dynamic mixer 11 is connected to the first inlet 14 on the second dynamic mixer 12, the catalyst is introduced into the second inlet 15 of the second dynamic mixer 12, and the discharge port 16 on the second dynamic mixer 12 is connected to the first inlet 14 on the third dynamic mixer 13. The second inlet 15 of the third dynamic mixer 13 is connected to the second outlet 24. The discharge port 16 of the third dynamic mixer 13 is connected to the reflux port 21 by a first reflux pipe 17. A first heat exchanger 171 is installed on the first reflux pipe 17. The discharge port 16 and the reflux port 21 of the third dynamic mixer 13 are connected through the first reflux pipe 17. The first outlet 23 is connected to the next stage reactor 2. The third outlet 25 is connected to the distillation column.

[0023] By adopting the above technical solution, the three-stage dynamic mixer 1 connected in series can effectively improve the mixing efficiency and realize the dynamic mixing and feeding of liquid phase. In addition, the system uses 3PN to disperse and reduce the concentration of hydrogen cyanide, which can reduce the concentration of hydrogen cyanide in the reactants during the mixing process and reduce the chance of high concentration hydrogen cyanide directly contacting the catalyst.

[0024] In this embodiment, the first dynamic mixer 11 first mixes 3PN with liquid hydrogen cyanide, the second dynamic mixer 12 mixes the mixture in the first dynamic mixer 11 with the catalyst, and the third dynamic mixer 13 further mixes the mixture in the second dynamic mixer 12 with the material at the bottom of the reactor 2 with a large volume flow rate.

[0025] In this embodiment, the reactor 2 includes two sets, namely a first reactor 26 and a second reactor 27. The second reactor 27 is provided with a series inlet 271. The first outlet 23 of the first reactor 26 is connected to the series inlet 271 of the second reactor 27. The second outlet 24 of the first reactor 26 is connected to the second inlet 15 of the third dynamic mixer 13. The discharge port 16 of the third dynamic mixer 13 is connected to the reflux port 21 of the first reactor 26 through a first reflux pipe 17. A second reflux pipe 272 is connected between the second outlet 24 of the second reactor 27 and the series inlet 271. A second heat exchanger 2721 is provided on the second reflux pipe 272. Hydrogen cyanide and 3PN are fully mixed in the reactor 2, and the third outlet 25 of the second reactor 27 discharges the product. In other embodiments, the reactor 2 can also be configured as multiple sets, with two or more stages of reactor 2 connected in series, which can achieve the purpose of continuous feeding reaction.

[0026] In this embodiment, both the first heat exchanger 171 and the second heat exchanger 2721 are external heat exchangers, which can remove the heat generated by the hydrocyanation reaction and effectively avoid a large number of side reactions caused by overheating during the reaction process.

[0027] In this embodiment, the flow rate of liquid hydrogen cyanide is set to am³ / h, the flow rate of 3PN is set to bm³ / h, the flow rate of catalyst is set to cm³ / h, a:b:c is 1:5:5, the flow rate of the first inlet 14 on the second dynamic mixer 12 is (a+b) m³ / h, the flow rate of the first inlet 14 on the third dynamic mixer 13 is (a+b+c) m³ / h, and in this embodiment, the flow rate of liquid hydrogen cyanide is set to 3 m³ / h, the flow rate of 3PN is set to 15 m³ / h, and the flow rate of catalyst is set to 15 m³ / h.

[0028] In this embodiment, the dynamic mixer 1 includes a stirring assembly 18 and a mixing chamber 19. A first inlet 14, a second inlet 15, and a discharge outlet 16 are all interconnected with the mixing chamber 19. A baffle plate 191 is installed inside the mixing chamber 19 at the discharge outlet 16. The baffle plate 191 includes a connecting portion 1911 and a flow-blocking portion 1912. The connecting portion 1911 is fixedly connected to the interior of the mixing chamber 19, and a first gap 1913 is provided between the flow-blocking portion 1912 and the inner wall of the mixing chamber 19. At the bottom end face of the mixing chamber 19, the height of the flow-blocking part 1912 is higher than the height of the discharge port 16. A baffle 192 is provided inside the mixing chamber 19, and a second gap 1921 is provided between the baffle 192 and the inner wall of the mixing chamber 19. The flow-blocking plate 191 adopts the overflow weir principle, which can ensure the uniformity and stability of the discharge from the discharge port 16. The baffle 192 can increase the disturbance, thereby effectively improving the mixing efficiency of the material in the mixing chamber 19, making the dynamic mixer 1 more practical.

[0029] In this embodiment, the mixing chamber 19 includes a mixing section 193 and an accumulation section 194. The bottom end face of the accumulation section 194 is set as an arc surface structure. The first feed port 14, the second feed port 15, and the discharge port 16 are all connected to the mixing section 193. The bottom end face of the baffle 192 is flush with the bottom end face of the mixing section 193.

[0030] In this embodiment, the maximum inner diameter of the mixing chamber 19 is set to φ, the height of the mixing section 193 is set to H1, the height of the accumulation section 194 is set to H2, the height of the mixing chamber 19 is H3, H3=H1+H2, φ:H1 is 1:(1-1.5), φ:H2 is 1:(0.2-0.4), the width of the baffle 192 is set to W1, the height of the baffle 192 is set to H4, and φ:W1 is 1:(0.05-0.4). 1) H4:H1 is 1:(1-1.5), the width of the second gap 1921 is set to W2, φ:W2 is 1:(0.01-0.03). In this embodiment, φ:H1 is 1:1.25, φ:H2 is 1:0.3125, φ:W1 is 1:0.075, H4:H1 is 1:1.25, and φ:W2 is 1:0.025, which can make the baffle 192 have a better disturbance effect in the mixing chamber 19.

[0031] In this embodiment, the stirring assembly 18 includes a stirring shaft 181 and stirring blades 182. The stirring blades 182 include two sets, which are respectively distributed in the middle of the mixing section 193 and at the connection between the mixing section 193 and the accumulation section 194. The diameter of the stirring shaft 181 is set to D1, the maximum outer diameter of the stirring blades 182 is set to D2, and the distance between the two sets of stirring blades 182 is set to H5. The ratio of φ:D1 is 1:(0.1-0.2), φ:D2 is 1:(0.3-0.8), and H5:H1 is 1:(2-3). In this embodiment, φ:D1 is 1:0.1125, φ:D2 is 1:0.5, and H5:H1 is 1:2.5, which can improve the mixing effect of the materials in the mixing chamber 19.

[0032] In this embodiment, the dynamic mixer 1 is equipped with a frequency converter 10 for driving the stirring shaft 181 to rotate. The frequency converter 10 is equipped with a cooler 101, which is located between the mixing chamber 19 and the frequency converter 10, thereby improving the safety of the dynamic mixer 1.

[0033] Based on the above description in this specification, those skilled in the art will also understand that the following terms used, such as "upper," "lower," "front," "rear," "left," "right," "width," "horizontal," "top," "bottom," "inner," and "outer," which indicate orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings of this specification. They are only for the purpose of facilitating the explanation of the present invention and simplifying the description, and do not explicitly or implicitly suggest that the device or element involved must have the specific orientation, or be constructed and operated in a specific orientation. Therefore, the above-mentioned orientation or positional relationship terms should not be understood or interpreted as limitations on the present invention.

[0034] In addition, in the description of this specification, "multiple" means at least two, such as two, three or more, etc., unless otherwise expressly and specifically defined.

Claims

1. A mixing system for the hydrocyanation of adiponitrile, characterized in that, It includes a dynamic mixer and a reaction vessel. The dynamic mixer includes three sets, namely a first dynamic mixer, a second dynamic mixer and a third dynamic mixer. The dynamic mixer is provided with a first feed port, a second feed port and a discharge port. The reaction vessel is provided with a reflux port, a first discharge port, a second discharge port and a third discharge port. Liquid hydrogen cyanide is introduced into the first inlet of the first dynamic mixer, 3PN is introduced into the second inlet of the first dynamic mixer, the discharge port on the first dynamic mixer is connected to the first inlet on the second dynamic mixer, the catalyst is introduced into the second inlet of the second dynamic mixer, and the discharge port on the second dynamic mixer is connected to the first inlet on the third dynamic mixer. The second inlet of the third dynamic mixer is connected to the second outlet. The discharge port and the reflux port of the third dynamic mixer are connected by a first reflux pipe. A first heat exchanger is installed on the first reflux pipe. The discharge port and the reflux port of the third dynamic mixer are connected through the first reflux pipe. The first outlet is connected to the next stage reactor. The third outlet is connected to the distillation column.

2. The mixing system for the hydrocyanation of adiponitrile according to claim 1, characterized in that, The reactor includes two sets, namely a first reactor and a second reactor. The second reactor is provided with a series inlet. The first outlet of the first reactor is connected to the series inlet of the second reactor. The second outlet of the first reactor is connected to the second inlet of a third dynamic mixer. The discharge port of the third dynamic mixer is connected to the reflux port of the first reactor through a first reflux pipe. A second reflux pipe is connected between the second outlet of the second reactor and the series inlet. A second heat exchanger is provided on the second reflux pipe.

3. The mixing system for the hydrocyanation of adiponitrile according to claim 1, characterized in that, The flow rate of liquid hydrogen cyanide is set to am³ / h, the flow rate of 3PN is set to bm³ / h, the flow rate of catalyst is set to cm³ / h, a:b:c is 1:5:5, the flow rate of the first inlet of the second dynamic mixer is (a+b) m³ / h, and the flow rate of the first inlet of the third dynamic mixer is (a+b+c) m³ / h.

4. The mixing system for the hydrocyanation of adiponitrile according to claim 1, characterized in that, The dynamic mixer includes a stirring assembly and a mixing chamber. A first inlet, a second inlet, and a discharge outlet are all connected to the mixing chamber. A baffle plate is installed inside the mixing chamber at the discharge outlet. The baffle plate includes a connecting part and a flow-blocking part. The connecting part is fixedly connected to the inside of the mixing chamber. A first gap is provided between the flow-blocking part and the inner wall of the mixing chamber. Based on the bottom end face of the mixing chamber, the height of the flow-blocking part is higher than the height of the discharge outlet. A baffle is installed inside the mixing chamber. A second gap is provided between the baffle and the inner wall of the mixing chamber.

5. A mixing system for the hydrocyanation of adiponitrile according to claim 4, characterized in that, The mixing chamber includes a mixing section and a stacking section. The bottom end face of the stacking section is set as an arc surface structure. The first feed port, the second feed port, and the discharge port are all connected to the mixing section. The bottom end face of the baffle is flush with the bottom end face of the mixing section.

6. A mixing system for the hydrocyanation of adiponitrile according to claim 5, characterized in that, The maximum inner diameter of the mixing chamber is set to φ, the height of the mixing section is set to H1, the height of the accumulation section is set to H2, the height of the mixing chamber is set to H3, H3=H1+H2, φ:H1 is 1:(1-1.5), φ:H2 is 1:(0.2-0.4), the width of the baffle is set to W1, the height of the baffle is set to H4, φ:W1 is 1:(0.05-0.1), H4:H1 is 1:(1-1.5), the width of the second gap is set to W2, φ:W2 is 1:(0.01-0.03).

7. A mixing system for the hydrocyanation of adiponitrile according to claim 6, characterized in that, φ:H1 is 1:1.25, φ:H2 is 1:0.3125, φ:W1 is 1:0.075, H4:H1 is 1:1.25, and φ:W2 is 1:0.

025.

8. A mixing system for the hydrocyanation of adiponitrile according to claim 6, characterized in that, The mixing assembly includes a mixing shaft and mixing blades. The mixing blades are divided into two sets, which are respectively distributed in the middle of the mixing section and at the connection between the mixing section and the accumulation section. The diameter of the mixing shaft is set to D1, the maximum outer diameter of the mixing blades is set to D2, and the distance between the two sets of mixing blades is set to H5. The ratio of φ:D1 is 1:(0.1-0.2), the ratio of φ:D2 is 1:(0.3-0.8), and the ratio of H5:H1 is 1:(2-3).

9. A mixing system for the hydrocyanation of adiponitrile according to claim 8, characterized in that, φ:D1 is 1:0.1125, φ:D2 is 1:0.5, and H5:H1 is 1:2.

5.

10. A mixing system for the hydrocyanation of adiponitrile according to claim 8, characterized in that, The dynamic mixer is equipped with a frequency converter for driving the stirring shaft to rotate. A cooler is installed on the frequency converter and is located between the mixing chamber and the frequency converter.

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