Multi-section reactor device for continuous polymerization of nylon 1012 and continuous polymerization method

Abstract

The invention discloses a multistage reactor device for continuous polymerization of nylon 1012 and a continuous polymerization method, the multistage reactor device comprises a salt forming reactor, a refined salt tank, a flash evaporation reactor, a polymerizer, a vertical reactor I, a horizontal reactor II, an amine storage tank, a solvent tank and an acid storage tank, diamine is stored in the amine storage tank, binary acid is stored in the acid storage tank, and a solvent is stored in the solvent tank. The salt forming reactor is respectively connected with the amine storage tank, the solvent tank and the acid storage tank, the salt forming reactor is connected with the refined salt tank, the refined salt tank is connected with the salt preheater, the salt preheater is connected with the reactor, the reactor is connected with the flash evaporation reactor, the flash evaporation reactor is connected with the polymerizer, and the polymerizer is connected with the underwater granulator. The underwater granulator is connected with the drying vibrating screen, and the drying vibrating screen is connected with the packaging system. The production operation is simple, the efficiency is high, the production cost is low, the product quality is improved, and the method is suitable for large-scale production.

Description

Technical Field

[0001] The invention relates to the technical field of continuous polymerization of nylon 1012, and in particular to a multi-stage reactor device and a continuous polymerization method for continuous polymerization of nylon 1012. Background Art

[0002] Nylon 1012 is the product of the polymerization of two monomers, decanediamine and dodecanedioic acid. It has the characteristics of low water absorption, good dimensional stability, good toughness, high strength, etc., and the raw material sources are wide and the cost is low. It is expected to replace nylon 11 and nylon 12 and become the main force in the market. At present, the production of nylon 1012 at home and abroad is mainly produced through the intermittent polymerization process. The intermittent production operation of salt formation-concentration-prepolymerization-polymerization is simple, but there are problems such as low production efficiency, unstable product quality, inability to fully utilize the reactor, and inability to produce on a large scale. Therefore, it is of great significance and value to establish a continuous production line for nylon 1012.

[0003] The commonly used nylon 66 continuous polymerization device currently uses acid and amine as raw materials. A salt solution is prepared in a salt-forming reactor. The salt solution is filtered and transported to a refined salt tank, and then transported to a concentration tank after passing through a preheater. The concentrated salt solution enters a U-shaped tubular reactor after passing through a preheater to undergo a prepolymerization reaction. The material is then transported to a flash reactor and a polymerization reactor in turn for a condensation reaction. After the melt viscosity reaches the requirement, the material is discharged, granulated, and packaged.

[0004] The precipitation temperature of nylon 1012 salt is high, exceeding 100°C. When preparing nylon 1012 through a continuous polymerization device of nylon 66, the salt solution is difficult to transport normally, and more amine loss will be caused, resulting in an imbalance in the molar ratio of acid and amine, resulting in end-capping, which affects the quality and performance of the product. In addition, the traditional U-shaped tubular reactor has low heat exchange intensity, which limits the production capacity. If the production capacity is to be increased, the U-shaped tubular reactor is often designed to be very long, which increases equipment consumption and floor space, and increases production costs. Summary of the invention

[0005] The present invention is to overcome the shortcomings of the above-mentioned prior art and provide a multi-stage reactor device and a continuous polymerization method for continuous polymerization of nylon 1012. The present invention uses a continuous reaction device to carry out polymerization production of nylon 1012, and continuously operates from feeding-salting-polymerization-packaging. Compared with the existing intermittent reaction production, the production operation is simple, the efficiency is high, the production cost is low, and it is suitable for large-scale production; the salt solution of the present invention does not need to pass through a concentration reactor, and can enter the reactor after passing through a preheater; the multi-stage reactor can be heated by a composite heating method of heat transfer oil and steam to improve the heat exchange efficiency; the three independent heating circuits can achieve stage-by-stage heating, reduce the amine loss caused by the temperature difference, and improve the product quality.

[0006] The technical solution adopted by the present invention to solve the technical problem is:

[0007] A multi-stage reactor device for continuous polymerization of nylon 1012 comprises a salt-forming reactor, a refined salt tank, a flash reactor, a polymerizer, a vertical reactor I, a horizontal reactor II, an amine storage tank, a solvent tank, and an acid storage tank. The amine storage tank stores diamine, the acid storage tank stores dibasic acid, and the solvent tank stores solvent. The salt-forming reactor is connected to the amine storage tank, the solvent tank, and the acid storage tank, respectively. The salt-forming reactor is connected to the refined salt tank, the refined salt tank is connected to a salt preheater, the salt preheater is connected to the reactor, the reactor is connected to the flash reactor, the flash reactor is connected to the polymerizer, the polymerizer is connected to an underwater pelletizer, the underwater pelletizer is connected to a drying vibration screen, and the drying vibration screen is connected to a packaging system.

[0008] The reactor comprises a reactor I and a reactor II, wherein the reactor I is connected to the reactor II, wherein the reactor I is connected to the salt preheater via a gear pump A1, and the reactor II is connected to the flash reactor via a gear pump A2; the reactor II is connected to a steam condensation recovery device; and a plurality of steam condensation recovery devices are provided.

[0009] The reactor I and the reactor II both include a reactor inner cavity, a heat transfer oil pipeline C surrounding the inner cavity, and a reactor shell that wraps the two. The shell and the inner cavity form a jacket, and the jacket is connected to a steam valve, forming a composite heating system of heat transfer oil and steam.

[0010] The reactor II is provided with three independent heating circuits, and the temperatures of the three independent heating circuits are different.

[0011] The polymerizer includes a pre-polymerizer and a post-polymerizer. The pre-polymerizer is connected to the post-polymerizer via a gear pump A3. The post-polymerizer may include multiple parallel polymerizers. The multiple parallel post-polymerizers are connected to a melt metering pump via a gear pump A4. The melt metering pump is connected to an underwater pelletizer.

[0012] A method for continuous polymerization of nylon 1012, using a multi-stage reactor device for continuous polymerization of nylon 1012, comprises the following steps:

[0013] A) Under a protective atmosphere, a diamine, a dibasic acid and a solvent are added to a salt-forming reactor, and stirred at 80 to 130° C. for 0.5 to 2 hours to obtain a clear salt solution; a sample is taken to test the pH value of the salt solution, and a processing aid is added after the pH value is qualified, and the qualified salt solution is filtered through a filter and then transported to a refined salt tank to wait for subsequent process treatment;

[0014] B) The salt solution in the refined salt tank is pumped to the reactor I through the salt preheater by a gear pump, and reacts at a temperature of 180-200°C for 1-3h, maintaining a pressure of 1.5-1.7MPa; then it is transported to the reactor II through the potential difference, and the three independent heating circuits of the reactor II are heated respectively, and the temperatures of the three circuits are 200-205°C, 205-210°C, and 210-215°C, respectively, and the reaction time of each section is 10-30min to obtain a prepolymer;

[0015] C) pumping the prepolymer into a flash reactor, heating the flash reactor and exhausting steam to allow the polymerization reaction to proceed in a positive direction to obtain further polycondensation products;

[0016] D) pumping the polycondensation product into a polymerization reactor through a corresponding gear pump, heating the polymerization reactor, discharging small molecule water generated by the reaction, and causing the molecular chain to grow rapidly to obtain a nylon resin;

[0017] E) After the resin meets the process requirements, it is discharged, granulated and packaged.

[0018] The protective atmosphere includes nitrogen and carbon dioxide; the diamine is decanediamine; the dibasic acid is dodecanedioic acid; the solvent is pure water; the salt-forming temperature is 100-120°C; the processing aids include catalysts, antioxidants, antioxidants, molecular weight regulators, and UV inhibitors;

[0019] The antioxidant includes one or more of antioxidant 1010, antioxidant 1086, antioxidant 1024, and antioxidant 1098;

[0020] The anti-ultraviolet agent includes UV-327, UV-660, Revonox @ 608、Chiguard @ One or more of N-442;

[0021] The catalyst includes one or more of phosphorous acid, sodium hypophosphite, triphenyl phosphite, zinc acetate, and antimony acetate.

[0022] The temperature of the reactor I is 190-200° C., and the pressure is 1.5-1.7 MPa.

[0023] The temperature of the flash reactor is 220-260° C., and the flash time is 1-3 hours.

[0024] In the polymerization reaction, the reaction temperature of the front polymerizer is 240-270° C., and the polymerization time is 0.5-1.5 h; the reaction temperature of the rear polymerizer I and the rear polymerizer II is 250-260° C., and the reaction time is 0.5-1 h.

[0025] The beneficial effects of the present invention are:

[0026] 1. The present invention uses a continuous reaction device to polymerize nylon 1012, and operates continuously from feeding-salting-polymerization-packaging. Compared with the existing batch reaction production, the production operation is simple, the efficiency is high, and the production cost is low. It is suitable for large-scale production and suitable for the industrial production and promotion of nylon 1012;

[0027] 2. The salt solution of the present invention does not need to pass through a concentration reactor, but can enter the reactor after passing through a preheater; the multi-stage reactor can be heated by a composite heating method of heat transfer oil and steam to improve the heat exchange efficiency.

[0028] 3. The three independent heating circuits can achieve step-by-step temperature increase, reduce amine loss caused by temperature difference, and improve product quality.

[0029] 4. Compared with intermittent production, the nylon 1012 prepared by the present invention has good batch stability and better product performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic diagram of the process flow of preparing nylon 1012 by continuous polymerization of the present invention.

[0031] Figure 2 It is a schematic structural diagram of a multi-stage reactor device of the present invention.

[0032] Description of the drawings: 1-amine storage tank, 2-solvent tank, 3-acid storage tank, 4-salt formation reactor, 5-refined salt tank, 6-salt preheater, 7-reactor I, 8-reactor II, 9-flash reactor, 10-prepolymerizer, 11-postpolymerizer I, 12-postpolymerizer II, 13-melt metering pump, 14-underwater pelletizer, 15-drying vibrating screen, 16-packaging system, A1-A4 are gear pumps, B1-B2 are steam condensation recovery devices, C is a heat transfer oil pipeline, Ⅰ, Ⅱ, Ⅲ are three independent heating circuits respectively. DETAILED DESCRIPTION

[0033] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments.

[0034] like Figure 1, as shown in FIG. 2 , a multi-stage reactor device for continuous polymerization of nylon 1012 includes a salt-forming reactor 4, a refined salt tank 5, a flash reactor 9, a polymerizer, a vertical reactor I7, a horizontal reactor II8, and an amine storage tank 1, a solvent tank 2, and an acid storage tank 3. The amine storage tank 1 stores diamine, the acid storage tank 3 stores dibasic acid, and the solvent tank 2 stores solvent, which can be water. The salt-forming reactor 4 is connected to the amine storage tank 1, the solvent tank 2, and the acid storage tank 3, respectively. The salt-forming reactor 4 is connected to the refined salt tank 5, the refined salt tank 5 is connected to the salt preheater 6, the salt preheater is connected to the reactor, the reactor is connected to the flash reactor 9, the flash reactor 9 is connected to the polymerizer, the polymerizer is connected to the underwater pelletizer 14, the underwater pelletizer 14 is connected to the drying vibration screen 15, and the drying vibration screen 15 is connected to the packaging system 16.

[0035] The reactor includes a reactor I7 and a reactor II8, wherein the reactor I7 is connected to the reactor II8, wherein the reactor I7 is connected to the salt preheater 6 via a gear pump A1, and the reactor II8 is connected to the flash reactor 9 via a gear pump A2; and the reactor II8 is connected to a steam condensation recovery device. There may be multiple steam condensation recovery devices, such as a steam condensation recovery device B1, a steam condensation recovery device B2, etc.

[0036] The reactor I7 and the reactor II8 both include a reactor inner cavity, a heat transfer oil pipeline C surrounding the inner cavity, and a reactor shell that wraps the two. The shell and the inner cavity form a jacket, and the jacket is connected to a steam valve, forming a composite heating system of heat transfer oil and steam. Figure 2 C in it is the heat transfer oil pipeline.

[0037] The reactor II is equipped with three independent heating circuits, namely Figure 2 The three independent heating circuits Ⅰ, Ⅱ and Ⅲ have different temperatures. The temperature rise can be controlled in stages, the amine loss caused by the large temperature difference of the material can be reduced, and the acid-amine molar ratio of the material can be stabilized.

[0038] The polymerizer includes a pre-polymerizer 10 and a post-polymerizer. The pre-polymerizer 10 is connected to the post-polymerizer through a gear pump A3. The post-polymerizer may include multiple parallel polymerizers, such as post-polymerizer I11, post-polymerizer II12, etc. Post-polymerizer I11 is the main reaction equipment, and II is used as a backup reactor. Multiple parallel post-polymerizers I11 and post-polymerizer II12 are connected to a melt metering pump 13 through a gear pump A4, and the melt metering pump 13 is connected to an underwater pelletizer 14.

[0039] A nylon 1012 continuous polymerization method comprising:

[0040] A) under a protective atmosphere, adding a diamine, a dibasic acid and a solvent into a salt-forming reactor 4, stirring and reacting at 80 to 130° C. for 0.5 to 2 hours to obtain a clear salt solution; sampling and testing the pH value of the salt solution, adding a processing aid after the pH value is qualified, filtering the qualified salt solution through a filter and transporting it to a refined salt tank 5 to wait for subsequent process treatment;

[0041] B) The salt solution in the refined salt tank 5 is pumped to the reactor I7 through the salt preheater with a gear pump, and reacts at a temperature of 180-200° C. for 1-3 hours, maintaining a pressure of 1.5-1.7 MPa; then it is transported to the reactor II8 through the potential difference, and the three independent heating circuits of the reactor II8 are heated respectively, and the temperatures of the three circuits are 200-205° C., 205-210° C., and 210-215° C., respectively, and the reaction time of each section is 10-30 min to obtain a prepolymer;

[0042] C) pumping the prepolymer into a flash reactor 9, heating and exhausting the flash reactor 9 to allow the polymerization reaction to proceed in a positive direction to obtain a further polycondensation product;

[0043] D) pumping the polycondensation product into a polymerization reactor through a corresponding gear pump, heating the polymerization reactor, discharging small molecule water generated by the reaction, and causing the molecular chain to grow rapidly to obtain a nylon resin;

[0044] E) After the resin meets the process requirements, it is discharged, granulated and packaged.

[0045] The protective atmosphere includes nitrogen and carbon dioxide; the diamine is decanediamine; the dibasic acid is dodecanedioic acid; the solvent is pure water; the salt-forming temperature is 100-120° C.; the processing aids include catalysts, antioxidants, antioxidants, molecular weight regulators, UV inhibitors, etc.

[0046] The antioxidant includes one or more of antioxidant 1010 , antioxidant 1086 , antioxidant 1024 , and antioxidant 1098 .

[0047] The anti-ultraviolet agent includes UV-327, UV-660, Revonox @ 608、Chiguard @ One or more of N-442.

[0048] The catalyst includes one or more of phosphorous acid, sodium hypophosphite, triphenyl phosphite, zinc acetate, and antimony acetate.

[0049] The temperature of the reactor I7 is 190-200° C., and the pressure is 1.5-1.7 MPa.

[0050] The flash evaporator temperature is 220-260° C., and the flash evaporation time is 1-3 hours.

[0051] In the polymerization reaction, the reaction temperature of the prepolymerizer 10 is 240-270° C., and the polymerization time is 0.5-1.5 h; the reaction temperature of the postpolymerizer I 11 and the postpolymerizer II 12 is 250-260° C., and the reaction time is 0.5-1 h.

[0052] The granulation method is underwater granulation to prevent oxidation of the material.

[0053] The heating method in all the above reaction processes is one or more of steam heating and thermal oil heating.

[0054] The technical solution of the present invention is further described below in conjunction with specific examples. This embodiment is implemented on the premise of the technical solution of the invention, and a detailed implementation method and specific operation process are given, but the protection scope of the present invention is not limited to the following embodiments.

[0055] Example 1

[0056] Weigh decanediamine and dodecanedioic acid according to the process requirements, add diamine and pure water into the salt-forming reactor 4, gradually start stirring and heating under nitrogen protection, control the temperature at about 100°C, gradually add an equimolar amount of dodecanedioic acid, and after the diacid is added, continue to react for 1 hour to obtain a salt solution; take samples for testing, add appropriate amount of acid or amine to adjust the pH value to the process requirements, then add processing aids such as antioxidants, anti-ultraviolet agents, catalysts, etc., and pump the qualified salt solution to the refined salt tank 5 for subsequent processes;

[0057] The salt solution in the refined salt tank is pumped to the reactor I7 through the salt preheater 6 by a gear pump, and reacts at a temperature of 180°C for 1 to 3 hours, maintaining a pressure of 1.5 MPa; then it is transported to the reactor II8 through the potential difference, and the three independent heating circuits of the reactor II8 are heated respectively, and the temperatures of the three circuits are 200 to 205°C, 205 to 210°C, and 210 to 215°C, respectively, and the reaction time of each section is 10 to 30 minutes to obtain a prepolymer;

[0058] The prepolymer is pumped to the flash reactor 9, and the flash reactor is heated by a heavy heating device to maintain the temperature at 255°C. The valve opening is regulated by the control system so that the pressure in the system drops to normal pressure after 2 hours, and the pressure reduction rate is kept constant to maintain the reaction liquid level stable, and further obtain the polycondensation product;

[0059] The polycondensation product is pumped to the prepolymerizer 10 through a gear pump, the gas valve is opened to put the system under nitrogen protection, the temperature is maintained at 270° C., the residence time is 60 min, and the system is pumped to the postpolymerizer I11 or the postpolymerizer II12); the gas valve of the postpolymerizer I11 or the postpolymerizer II12 is opened to put it under nitrogen protection, the temperature is maintained at 255° C., the residence time is 60 min, and the melt metering pump 13 is fed through a twin-screw device;

[0060] After being pelletized by the underwater pelletizer 14, the speed of the melt metering pump 13 and the speed of the underwater pelletizer 14 are adjusted according to the output to make the pellets meet the specifications. After being dried and vibrated by the drying vibrating screen 15, they enter the storage bin, are packaged by a loss-in-weight metering scale, and finally are vacuum packaged.

[0061] Example 2

[0062] Weigh decanediamine and dodecanedioic acid according to the process requirements, add diamine and pure water into the salt-forming reactor 4, gradually start stirring and heating under nitrogen protection, control the temperature at about 100°C, gradually add an equimolar amount of dodecanedioic acid, and after the diacid is added, continue to react for 1 hour to obtain a salt solution; take samples for testing, add appropriate amount of acid or amine to adjust the pH value to the process requirements, then add processing aids such as antioxidants, anti-ultraviolet agents, catalysts, etc., and pump the qualified salt solution to the refined salt tank 5 for subsequent processes;

[0063] The salt solution in the refined salt tank 5 is pumped to the reactor I7 through the salt preheater 6 by a gear pump, and reacts at a temperature of 200°C for 1 to 3 hours, maintaining a pressure of 1.7 MPa; then it is transported to the reactor II8 through the potential difference, and the three independent heating circuits of the reactor II8 are heated respectively, and the temperatures of the three circuits are 200 to 205°C, 205 to 210°C, and 210 to 215°C, respectively, and the reaction time of each section is 10 to 30 minutes to obtain a prepolymer;

[0064] The prepolymer is pumped to the flash reactor 9, and the flash reactor 9 is heated by a heavy heating device to maintain the temperature at 260° C. The valve opening is regulated by a control system to reduce the pressure in the system to normal pressure after 1 hour, and the pressure reduction rate is kept constant to maintain the reaction liquid level stable, and further obtain a polycondensation product;

[0065] The polycondensation product is pumped to the prepolymerizer 10 through a gear pump, the gas valve is opened to put the system under nitrogen protection, the temperature is maintained at 240° C., the residence time is 30 min, and the system is pumped to the postpolymerization reactor I11 or the postpolymerization reactor II12; the gas valve of the postpolymerization reactor I11 or the postpolymerization reactor II12 is opened to put it under nitrogen protection, the temperature is maintained at 255° C., the residence time is 30 min, and the melt metering pump 13 is fed through a twin-screw device;

[0066] After being pelletized by an underwater pelletizer, the speed of the melt metering pump 13 and the speed of the underwater pelletizer 14 are adjusted according to the output to ensure that the pellets meet the specifications. After being dried and vibrated by a drying vibrating screen 15, they enter the storage bin, are packaged by a loss-in-weight metering scale, and finally are vacuum packaged.

[0067] Example 3

[0068] Weigh decanediamine and dodecanedioic acid according to the process requirements, add diamine and pure water into the salt-forming reactor 4, gradually start stirring and heating under nitrogen protection, control the temperature at about 100°C, gradually add an equimolar amount of dodecanedioic acid, and after the diacid is added, continue to react for 1 hour to obtain a salt solution; take samples for testing, add appropriate amount of acid or amine to adjust the pH value to the process requirements, then add processing aids such as antioxidants, anti-ultraviolet agents, catalysts, etc., and pump the qualified salt solution to the refined salt tank 5 for subsequent processes;

[0069] The salt solution in the refined salt tank 5 is pumped to the reactor I7 through the salt preheater 6 by a corresponding gear pump, and reacts at a temperature of 190°C for 1 to 3 hours, maintaining a pressure of 1.6 MPa; then it is transported to the reactor II8 through the potential difference, and the three independent heating circuits of the reactor II8 are heated respectively, and the temperatures of the three circuits are 200 to 205°C, 205 to 210°C, and 210 to 215°C, respectively, and the reaction time of each section is 10 to 30 minutes to obtain a prepolymer;

[0070] The prepolymer is pumped to the flash reactor 9, and the flash reactor 9 is heated by a heavy heating device to maintain the temperature at 220° C. The valve opening is regulated by a control system to reduce the pressure in the system to normal pressure after 3 hours, and the pressure reduction rate is kept constant to maintain the reaction liquid level stable, and further obtain a polycondensation product;

[0071] The polycondensation product is pumped to the prepolymerizer 10 through a gear pump, the gas valve is opened to put the system under nitrogen protection, the temperature is maintained at 250° C., the residence time is 90 min, and the system is pumped to the postpolymerizer I11 or the postpolymerizer II12; the gas valve of the postpolymerizer I11 or the postpolymerizer II12 is opened to put it under nitrogen protection, the temperature is maintained at 255° C., the residence time is 45 min, and the melt metering pump 13 is fed through a twin-screw device;

[0072] After being pelletized by the underwater pelletizer 14, the speed of the melt metering pump 13 and the speed of the underwater pelletizer 14 are adjusted according to the output to make the pellets meet the specifications. After being dried and vibrated by the drying vibrating screen 15, they enter the storage bin, are packaged by a loss-in-weight metering scale, and finally are vacuum packaged.

[0073] Comparative Example 1

[0074] The formulation and process are the same as those in Example 1, but the production process adopts intermittent polymerization.

[0075] The performance of the nylon 1012 resin obtained in the above examples and comparative examples was tested, and the test results are shown in Table 1.

[0076] Table 1: Comparison of various properties of nylon 1012 obtained in the embodiments of the present invention and the comparative examples of the prior art

[0077]

[0078]

[0079] In addition, the present invention has carried out exploratory tests on other process conditions and operations with reference to the above embodiments, and obtained relatively ideal results.

[0080] The above is a preferred embodiment of the present invention, and the description of the specific embodiment is only used to better understand the concept of the present invention. For those skilled in the art, several improvements or equivalent replacements can be made according to the principles of the present invention, and these improvements or equivalent replacements are also considered to fall within the protection scope of the present invention.

Claims

1. A multi-stage reactor device for continuous polymerization of nylon 1012, comprising a salt-forming reactor, a refined salt tank, a flash reactor, a polymerizer, a vertical reactor I, a horizontal reactor II, and also comprising an amine storage tank, a solvent tank, and an acid storage tank, wherein the amine storage tank stores diamine, the acid storage tank stores dibasic acid, and the solvent tank stores solvent, wherein the salt-forming reactor is connected to the amine storage tank, the solvent tank, and the acid storage tank, respectively, the salt-forming reactor is connected to the refined salt tank, the refined salt tank is connected to a salt preheater, the salt preheater is connected to the reactor, the reactor is connected to the flash reactor, the flash reactor is connected to the polymerizer, the polymerizer is connected to an underwater pelletizer, the underwater pelletizer is connected to a dry vibrating screen, and the dry vibrating screen is connected to a packaging system.

2. The multi-stage reactor device for continuous polymerization of nylon 1012 according to claim 1, characterized in that: The reactor comprises a reactor I and a reactor II, wherein the reactor I is connected to the reactor II, wherein the reactor I is connected to the salt preheater via a gear pump A1, and the reactor II is connected to the flash reactor via a gear pump A2; the reactor II is connected to a steam condensation recovery device; and a plurality of steam condensation recovery devices are provided.

3. The multi-stage reactor device for continuous polymerization of nylon 1012 according to claim 2, characterized in that: The reactor I and the reactor II both include a reactor inner cavity, a heat transfer oil pipeline C surrounding the inner cavity, and a reactor shell that wraps the two. The shell and the inner cavity form a jacket, and the jacket is connected to a steam valve, forming a composite heating system of heat transfer oil and steam.

4. The multi-stage reactor device for continuous polymerization of nylon 1012 according to claim 1, characterized in that: The reactor II is provided with three independent heating circuits, and the temperatures of the three independent heating circuits are different.

5. The multi-stage reactor device for continuous polymerization of nylon 1012 according to claim 3, characterized in that: The polymerizer includes a pre-polymerizer and a post-polymerizer. The pre-polymerizer is connected to the post-polymerizer via a gear pump A3. The post-polymerizer may include multiple parallel polymerizers. The multiple parallel post-polymerizers are connected to a melt metering pump via a gear pump A4. The melt metering pump is connected to an underwater pelletizer.

6. A nylon 1012 continuous polymerization method, characterized in that: The multi-stage reactor device for continuous polymerization of nylon 1012 as claimed in claim 5 comprises the following steps: A) Under a protective atmosphere, a diamine, a dibasic acid and a solvent are added to a salt-forming reactor, and stirred at 80 to 130° C. for 0.5 to 2 hours to obtain a clear salt solution; a sample is taken to test the pH value of the salt solution, and a processing aid is added after the pH value is qualified, and the qualified salt solution is filtered through a filter and then transported to a refined salt tank to wait for subsequent process treatment; B) The salt solution in the refined salt tank is pumped to the reactor I through the salt preheater by a gear pump, and reacts at a temperature of 180-200°C for 1-3h, maintaining a pressure of 1.5-1.7MPa; then it is transported to the reactor II through the potential difference, and the three independent heating circuits of the reactor II are heated respectively, and the temperatures of the three circuits are 200-205°C, 205-210°C, and 210-215°C, respectively, and the reaction time of each section is 10-30min to obtain a prepolymer; C) pumping the prepolymer into a flash reactor, heating the flash reactor and exhausting steam to allow the polymerization reaction to proceed in a positive direction to obtain further polycondensation products; D) pumping the polycondensation product into a polymerization reactor through a corresponding gear pump, heating the polymerization reactor, discharging small molecule water generated by the reaction, and causing the molecular chain to grow rapidly to obtain a nylon resin; E) After the resin meets the process requirements, it is discharged, granulated and packaged.

7. The continuous polymerization method of nylon 1012 according to claim 6, characterized in that: The protective atmosphere includes nitrogen and carbon dioxide; the diamine is decanediamine; the dibasic acid is dodecanedioic acid; the solvent is pure water; the salt-forming temperature is 100-120°C; the processing aids include catalysts, antioxidants, antioxidants, molecular weight regulators, and UV inhibitors; The antioxidant includes one or more of antioxidant 1010, antioxidant 1086, antioxidant 1024, and antioxidant 1098; The anti-ultraviolet agent includes UV-327, UV-660, Revonox @ 608、Chiguard @ One or more of N-442; The catalyst includes one or more of phosphorous acid, sodium hypophosphite, triphenyl phosphite, zinc acetate, and antimony acetate.

8. The continuous polymerization method of nylon 1012 according to claim 6, characterized in that: The temperature of the reactor I is 190-200° C., and the pressure is 1.5-1.7 MPa.

9. The continuous polymerization method of nylon 1012 according to claim 6, characterized in that: The temperature of the flash reactor is 220-260° C., and the flash time is 1-3 hours.

10. The continuous polymerization method of nylon 1012 according to claim 6, characterized in that: In the polymerization reaction, the reaction temperature of the front polymerizer is 240-270° C., and the polymerization time is 0.5-1.5 h; the reaction temperature of the rear polymerizer I and the rear polymerizer II is 250-260° C., and the reaction time is 0.5-1 h.

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