Production process and system capable of continuously preparing methacrylic acid polymer and control system

Abstract

The invention discloses a production process and system capable of continuously preparing a methacrylic acid polymer and a control system, and belongs to the technical field of methacrylic acid polymer production. Firstly, the invention provides a production process which comprises the steps of burdening, prepolymerization, polymerization and deliming separation, and key process conditions (such as temperature, oxygen content, polymerization conversion rate and the like) are controlled; secondly, providing a suitable production system and a control system, ensuring effective controllability of polymerization conversion rate and reaction heat, maintaining dynamic balance between the polymerization conversion rate and the reaction heat, and finally realizing stability, orderliness and controllability of a methacrylic acid polymer production process so as to meet industrial, automatic and economic large-scale production requirements; effective premise and guarantee are provided for processing and production of new materials; and meanwhile, optical-grade polymerization products are produced to meet actual requirements.

Description

Technical Field

[0001] The invention relates to a production process, a system and a control system capable of continuously preparing a methacrylic acid series polymer, and belongs to the technical field of methacrylic acid series polymer production. Background Art

[0002] Methacrylic acid polymers are a class of polymer materials with broad application prospects. They are polymer compounds formed by polymerization of methacrylic acid or its derivatives. Methacrylic acid polymers are unique in chemical structure. Their alkyl side chains are methyl groups instead of hydrogen atoms. Such polymers usually have high transparency and good weathering resistance. Among them, polymethyl methacrylate (PMMA) is an important member of methacrylic acid polymers. Polymethyl methacrylate, also known as organic glass or acrylic, is a highly transparent, amorphous polymer.

[0003] At present, the mainstream polymerization processes include: 1. Suspension polymerization method uses water as the continuous phase, the viscosity of the polymerization system is low, and the viscosity of the material does not change much during the reaction. It has the advantages of easy removal of polymerization reaction heat, easy temperature control, safer production operation, and short process flow. However, due to the large amount of water phase used, the production capacity of suspension polymerization is low and it is not suitable for large-scale continuous production; and the preparation process requires complicated processes such as filtration, washing, and drying, which reduces production efficiency, and there are also problems such as poor product purity and large amounts of sewage; Second, solution polymerization method: the viscosity of the polymerization system is low, mass transfer and heat transfer are easy to control, the operating conditions are stable, large-scale and continuous production can be carried out, and there is no wastewater treatment problem. However, the recovery and treatment process of the existing organic solvent is relatively complicated and costly, which may cause environmental pollution problems; 3. Bulk polymerization is suitable for continuous production, with high product purity and transparency, high polymerization conversion rate, only a small amount of unreacted monomers need to be recovered, and low energy consumption. However, due to the high viscosity of the polymerization system, mass transfer and heat transfer control are difficult, and therefore, the equipment and process operation procedures are demanding. For this reason, a lot of research has been conducted, such as: the prior art CN102933610A discloses a "method for producing methacrylic acid polymers", which is mainly based on a bulk polymerization process, and the final product is obtained by connecting a fully mixed reactor and a pipeline reactor in series; the prior art CN104955853A discloses a "method for producing methacrylic acid polymer compositions and molded products", which first feeds the polymerization monomers and additives into a first fully mixed reactor through the reactor supply port, and after the reaction, transfers to a second fully mixed reactor to continue the reaction, and passes through a second fully mixed reactor. The obtained methacrylic acid polymer composition is taken out from the discharge port of the fully mixed reactor; the prior art CN101338001A discloses "optical grade polymethyl methacrylate continuous solution polymerization process and equipment used therein", wherein the equipment used is composed of a refining distillation device, a polymerization reaction device, a two-stage devolatilization device and a wire drawing and granulation device connected in series; CN103130945A and CN103130946A both provide a method for continuous polymerization of PMMA, which adopts three fully mixed reactors connected in series, and the process for continuously producing polymethyl methacrylate by prepolymerization, secondary polymerization and tertiary polymerization in sequence is a method of prepolymerization, secondary polymerization and tertiary polymerization in advance, thereby realizing the production of PMMA; Although the above-mentioned prior arts all adopt bulk polymerization to produce methacrylic acid polymers, and realize the innovation and optimization of the polymerization process, the control of the conversion rate and reaction heat in the polymerization process is generally achieved by adding reaction sections or equipment to control the conversion rate in each section or equipment, and finally realizing the reduction of reaction heat, that is, there are still technical problems: The molecular weight and regularity of the raw monomers after polymerization cannot be effectively controlled, and the reaction heat cannot be accurately, efficiently and quickly removed. The degree of polymerization and the reaction heat affect each other. The higher the reaction polymerization conversion rate, the higher the reaction heat. Conversely, if the reaction heat is not removed in time, the polymerization rate will be accelerated, the conversion rate will increase, and ultimately the effective production of methacrylic acid polymers cannot be achieved. In addition, in the current methacrylic acid polymer production process, it is impossible to dynamically and controllably remove heat quickly and reversely maintain the reaction rate, that is, the corresponding automatic control technology is still blank.

[0004] Therefore, a methacrylic acid polymer production process is needed which can effectively control the polymerization conversion rate and reaction heat, realize stable industrial large-scale production, and realize automated control. Summary of the invention

[0005] In order to overcome the shortcomings of the prior art, a production process, system and control system for continuously preparing methacrylic acid polymers are proposed. In the present invention, by proposing a suitable production process, production system and control system, the effective controllability of polymerization conversion rate and reaction heat is guaranteed, and the dynamic balance between polymerization conversion rate and reaction heat is maintained, and finally the stability, orderliness and controllability of the methacrylic acid polymer production process are achieved to meet the needs of industrialized, automated and economical large-scale production, and provide an effective prerequisite guarantee for the processing and production of new materials; at the same time, optical-grade polymer products can be produced to meet actual needs.

[0006] In order to achieve the above technical objectives, the following technical solutions are proposed: The first purpose of the technical solution is to provide: a production process for continuously preparing methacrylic acid polymers, comprising the following steps: S1 batching: add the raw materials alkyl methacrylate monomer, alkyl acrylate monomer and (meth) acrylate cyclic ester monomer into the mixing buffer tank until the total volume of the raw materials accounts for 2 / 3 to 4 / 5 of the volume of the mixing buffer tank, then stop adding; The raw materials are mixed evenly to obtain a mixture; then, high-purity Ar or N is introduced into the mixing buffer tank. 2 , replace the gas in the mixing buffer tank; Among them, the following are controlled in the mixing buffer tank: the oxygen content in each monomer raw material is ≤1ppm; based on the sum of the monomer raw material mass as 100%, the methacrylate alkyl ester monomer content is 68-95%, the acrylate alkyl ester monomer content is 3-30%, and the (meth)acrylic acid cyclic ester monomer content is 2-15%; the pressure is 20-50KPa (gauge pressure), and the temperature is 20-50℃; S2 prepolymerization: adding the gas-substituted mixture obtained in step S1, the solvent and the auxiliary agent into a fully mixed reactor, heating the fully mixed reactor to 90-140°C at a rate of 1-3°C / min; then, staying for 30-240 min to obtain a prepolymerization reaction system; Among them, the fully mixed reactor is controlled: the amount of solvent added is 1-10% of the total amount of monomer raw materials, the amount of auxiliary agent added is 0.05-0.3% of the total amount of monomer raw materials; the difference between the actual maximum temperature of the prepolymerization reaction and the set temperature is not higher than 10°C, the pressure is 0.5-2.0MPa, the oxygen content is ≤2ppm, and the conversion rate of alkyl methacrylate monomer is 30-50%; S3 polymerization: the prepolymerization reaction system obtained in step S2 is introduced into a segmented tubular reactor, and the polymerization temperature in the segmented tubular reactor is controlled to be 140-200°C, the pressure is 1.5-3.5MPa, the amount of the auxiliary agent added again is 0.04-0.55%, and the moving speed of the material in the tubular reactor is 0.001-0.1 m / s, and finally, a slurry product is obtained; Furthermore, in the segmented shell-and-tube reactor, the temperature of each segment gradually increases in accordance with the direction of the material; Preferably, the segmented tubular reactor comprises a first reaction zone, a second reaction zone and a third reaction zone which are sequentially distributed from bottom to top, and the first reaction zone is controlled such that: the amount of the additive added again is 0.02-0.2% of the total amount of the monomer raw material, the material stays for 20-100 min, the temperature is 140-155° C., and the total conversion rate of the alkyl methacrylate monomer is accumulated to 40-55%; Control the second stage reaction zone: the amount of the additive added again is 0.01-0.2% of the total amount of the monomer raw material, the material stays for 10-80 minutes, the temperature is 155-175°C, and the total conversion rate of the alkyl methacrylate monomer is accumulated to 50-65%; Control the third stage reaction zone: the amount of the additive added again is 0.01-0.15% of the total amount of the monomer raw material, the material stays for 5-60 minutes, the temperature is 175-200°C, and the total conversion rate of the alkyl methacrylate monomer is accumulated to 60-75%; At the same time, the temperature relationship in the three reaction zones is: 7°C ≤ temperature of the second reaction zone - temperature of the first reaction zone = temperature of the third reaction zone - temperature of the second reaction zone ≤ 20°C, that is, the temperature difference between the reactant zones of adjacent sections is equal, and 7°C ≤ temperature difference ≤ 20°C; S4 deashing and separation: the slurry product obtained in step S3 is introduced into a deashing and extruding integrated machine, and deashing and separation is performed for 10 to 30 minutes at a temperature of 200 to 280° C. and an absolute pressure of 10 to 40 KPa to obtain a polymer material and a waste material including unreacted monomers, solvents, oligomers and additives (the waste material is gas. In the deashing and extruding integrated machine, the waste material is gasified and then separated from the polymer material); Carry out subsequent granulation and packaging of polymer materials; The waste materials including unreacted monomers, solvents, oligomers and additives are introduced into the monomer recovery device, and after separation, waste liquid, waste gas, unreacted monomers and solvents are obtained. The recovered unreacted monomers can be recycled to the batching process.

[0007] The second purpose of the technical solution is to provide: a production system for continuously preparing methacrylic acid polymers, including a mixing buffer tank, a fully mixed reactor, a segmented tubular reactor and a deashing and extruding integrated machine; Mixing buffer tank: connected to an alkyl methacrylate monomer metering tank via an alkyl methacrylate monomer feed pipe, connected to an alkyl acrylate monomer metering tank via an alkyl acrylate monomer feed pipe, connected to a (meth)acrylate cyclic ester monomer metering tank via a (meth)acrylate cyclic ester monomer feed pipe, and connected to a protective gas storage tank via a protective gas inlet pipe I; a displacement gas outlet on the mixing buffer tank is connected to a displacement gas outlet pipe; and a material outlet on the mixing buffer tank is connected to a fully mixed reactor via a mixed material delivery pipe; The methacrylate alkyl ester monomer feed pipe is provided with an methacrylate alkyl ester monomer feed control valve and an methacrylate alkyl ester monomer metering pump, the acrylate alkyl ester monomer feed pipe is provided with an acrylate alkyl ester monomer feed control valve and an acrylate alkyl ester monomer metering pump, and the (meth)acrylate cyclic ester monomer feed pipe is provided with a (meth)acrylate cyclic ester monomer feed control valve and a (meth)acrylate cyclic ester monomer metering pump; the protective gas inlet pipe I is provided with a protective gas feed control valve I, the displacement gas outlet pipe is provided with an oxygen content analyzer and a gas displacement control valve, the mixing buffer tank is provided with a pressure sensor I and a temperature sensor I, and the mixed material delivery pipe is provided with a mixed material delivery pump; Fully mixed reactor: It is located at the rear of the mixing buffer tank. The fully mixed reactor is connected to the solvent metering tank through the solvent feed pipe, is also connected to the auxiliary agent metering tank through the auxiliary agent feed pipe I, and is also connected to the protective gas storage tank through the protective gas feed pipe II; A stirring device is provided in the fully mixed reactor, and a temperature control coil is provided on the stirring device. One end of the temperature control coil is connected to a heat transfer material inlet pipe, and the other end is connected to a heat transfer material discharge pipe; a three-paddle stirring mechanism is provided at the lower part of the stirring device, and the three-paddle stirring mechanism includes a blade assembly I, a blade assembly II and a blade assembly III which are sequentially distributed from bottom to top, and the blades in the blade assembly I are twisted clockwise by 35 to 45°C, the blades in the blade assembly II are twisted counterclockwise by 35 to 45°C, and the blades in the blade assembly III are twisted clockwise by 35 to 45°C; the upper discharge port of the fully mixed reactor is connected to the segmented tubular reactor through a prepolymerization reaction system delivery pipe; The solvent feed pipe is provided with a solvent feed control valve and a solvent metering pump, the auxiliary agent feed pipe I is provided with an auxiliary agent feed control valve I and an auxiliary agent metering pump I; the protective gas inlet pipe II is provided with a protective gas feed control valve II, the heat transfer material inlet pipe is provided with a heat transfer material feed control valve, and the heat transfer material discharge pipe is provided with a heat transfer material discharge control valve; the fully mixed reactor is provided with a pressure sensor II and a temperature sensor II; the prepolymerization reaction system delivery pipe is provided with a prepolymerization reaction system delivery pump; In addition, a heating jacket is provided on the outer side of the fully mixed reactor, the heat source in the heating jacket is high-temperature heat transfer oil, the inlet of the heating jacket is connected to a heat transfer oil inlet pipe Ⅰ (generally high-temperature heat transfer oil), and the outlet of the heating jacket is connected to a heat transfer oil outlet pipe Ⅰ; the heat transfer object in the temperature control coil is a liquid feed, the vaporization temperature of the heat transfer object under normal pressure is 5-10°C higher than the set reaction temperature in the fully mixed reactor, and the feed temperature of the heat transfer object is 5-10°C lower than the set reaction temperature, for example: when the set reaction temperature in the fully mixed reactor is 120°C, isoamyl alcohol with a boiling point of 131-132°C can be selected; when the set reaction temperature in the fully mixed reactor is 132°C, isoamyl acetate with a boiling point of 142°C can be selected; a heat transfer oil feed control valve Ⅰ is provided on the heat transfer oil inlet pipe Ⅰ, and a heat transfer oil discharge control valve Ⅰ is provided on the heat transfer oil outlet pipe Ⅰ; The segmented shell-and-tube reactor is arranged at the rear side of the station of the fully mixed reactor, and comprises a shell and at least two mixing units and at least two shell-and-tube reaction units arranged in the shell. The mixing units and the shell-and-tube reaction units are arranged at intervals and are distributed upward in sequence. A feed inlet is arranged on the bottom mixing unit, and a discharge port is arranged on the top shell-and-tube reaction unit. A continuous passage for polymerization reaction is formed between the feed inlet, the mixing unit, the shell-and-tube reaction unit and the discharge port. Each mixed flow unit is connected to an additive feed pipe II, the bottom tube-in-tube reaction unit is connected to a heat transfer oil inlet pipe II (generally high-temperature heat transfer oil), the top tube-in-tube reaction unit is connected to a heat transfer oil outlet pipe II, and the upper tube-in-tube reaction unit is connected to the lower tube-in-tube reaction unit through a heat transfer oil connecting pipe; the upper discharge port of the segmented tube-in-tube reactor is connected to the deashing and extruding integrated machine through a reactant conveying pipe; The mixed flow unit includes a mixed flow cavity connected to the auxiliary agent feed pipe II, the tube-in-tube reaction unit includes a tube-in-tube array arranged longitudinally, and the temperature control cavity between the tube-in-tube array and the shell is used to contain the heat transfer oil; Preferably, the temperature control cavity is also connected to a cold oil feed pipe (generally low-temperature heat transfer oil), that is, the high-temperature heat transfer oil and the low-temperature heat transfer oil are combined to jointly adjust the temperature of the temperature control cavity, thereby effectively controlling the temperature in the tube array to ensure the controllable progress of the reaction system; The additive feed pipe Ⅱ is provided with an additive feed control valve Ⅱ and an additive metering pump Ⅱ, the heat transfer oil inlet pipe Ⅱ is provided with a heat transfer oil feed control valve Ⅱ, the heat transfer oil outlet pipe Ⅱ is provided with a heat transfer oil discharge control valve Ⅱ, the cold oil feed pipe is provided with a cold oil feed control valve, and the reactant delivery pipe is provided with a reactant delivery pump; each mixed flow unit is provided with a pressure sensor Ⅲ and a temperature sensor Ⅲ, and the tube-in-tube reaction unit is provided with a pressure sensor Ⅳ and a temperature sensor Ⅳ; Deashing and extruding machine: It is installed at the rear side of the station of the segmented tubular reactor. The polymer outlet of the deashing and extruding machine is connected to the methacrylic acid polymer storage tank, the waste outlet of the deashing and extruding machine is connected to the monomer recovery device, and the monomer outlet of the monomer recovery device is connected to the mixing buffer tank through a recycling pipe; A continuous passage for the production of methacrylic acid series polymer is formed between the mixing buffer tank, the fully mixed reactor, the segmented tubular reactor, the deashing and extruding integrated machine and the methacrylic acid series polymer storage tank.

[0008] The third object of the technical solution is to provide: a control system for continuously preparing methacrylic acid polymers, which is arranged in a production system of methacrylic acid polymers, wherein the control system comprises a DCS controller, the DCS controller is connected to a human-machine interface via a data input interface, the DCS controller is connected to a data acquisition unit via a data feedback interface, and the DCS controller is connected to an execution unit via a data output interface; The DCS controller includes a batching control module, a prepolymerization control module and a polymerization control module; The data acquisition unit is arranged in the production system of the methacrylic acid series polymer, and the data acquisition unit comprises a sensor group for data acquisition and transmission in the production process of the methacrylic acid series polymer; The execution unit is arranged in the production system of methacrylic acid series polymer, and the execution unit comprises a group of equipment for preparing and regulating methacrylic acid series polymer; The DCS controller: on the one hand, receives the information of batching process and its regulation, pre-polymerization process and its regulation, polymerization process and its regulation, waste treatment process and its regulation and safety warning information input from the human-machine interface; on the other hand, receives the information of batching process, pre-polymerization process, polymerization process, waste treatment process and safety warning information fed back from the data acquisition unit, completes information analysis, comparison and judgment, issues data acquisition instructions through the data acquisition unit, and issues execution instructions through the execution unit; Human-machine interface: complete the input of batching process and its regulation information, prepolymerization process and its regulation information, polymerization process and its regulation information, waste treatment process and its regulation information, and safety warning information. The layout on the human-machine interface can be set with a multi-function table, corresponding identification icons, switch control keys, regulation control keys, etc. Data acquisition unit: receives data acquisition instructions from the DCS controller, completes the collection and transmission of information on the batching process and its regulation, information on the prepolymerization process and its regulation, information on the polymerization process and its regulation, information on the waste treatment process and its regulation, and safety warning information, and feeds back to the DCS controller; Execution unit: completes the instructions issued by the DCS controller.

[0009] Further, the sensor group includes an alkyl methacrylate monomer metering pump, an alkyl acrylate monomer metering pump and a (meth)acrylate cyclic ester monomer metering pump connected to the batching control module; It also includes a solvent metering pump, an auxiliary metering pump I, a pressure sensor I, a temperature sensor I, a pressure sensor II and a temperature sensor II connected to the prepolymerization control module; the solvent metering pump and the auxiliary metering pump I are also connected to the batching control module; It also includes an additive metering pump II, a pressure sensor III, a temperature sensor III, a pressure sensor IV and a temperature sensor IV connected to the polymerization control module; the additive metering pump II is also connected to the batching control module; Further, the equipment group includes an alkyl methacrylate monomer feed control valve, an alkyl acrylate monomer feed control valve, a (meth)acrylate cyclic ester monomer feed control valve, a protective gas feed control valve I, a mixed material delivery pump, a solvent feed control valve, an auxiliary agent feed control valve I and an auxiliary agent feed control valve II connected to the batching control module; the solvent feed control valve and the auxiliary agent feed control valve I are also connected to the prepolymerization control module, and the auxiliary agent feed control valve II is also connected to the polymerization control module; It also includes a protective gas feed control valve II, a heat transfer material feed control valve, a heat transfer material discharge control valve, a prepolymerization reaction system delivery pump, a heat transfer oil feed control valve I and a heat transfer oil discharge control valve I connected to the prepolymerization control module; It also includes a heat transfer oil feed control valve II, a heat transfer oil discharge control valve II, a cold oil feed control valve and a reactant delivery pump connected to the polymerization control module; Among them, the alkyl methacrylate monomer metering pump and the alkyl methacrylate monomer feeding control valve are interlocked by electrical signals, and the alkyl methacrylate monomer metering pump, the batching control module and the alkyl methacrylate monomer feeding control valve form a control loop through electrical signals; The alkyl acrylate monomer metering pump and the alkyl acrylate monomer feeding control valve are interlocked by electrical signals, and a control loop is formed between the alkyl acrylate monomer metering pump, the batching control module and the alkyl acrylate monomer feeding control valve through electrical signals; The (meth)acrylic acid cyclic ester monomer metering pump and the (meth)acrylic acid cyclic ester monomer feeding control valve are interlocked by electrical signals, and the (meth)acrylic acid cyclic ester monomer metering pump, the batching control module and the (meth)acrylic acid cyclic ester monomer feeding control valve form a control loop by electrical signals; The solvent metering pump and the solvent feed control valve are interlocked by electrical signals, and a control loop is formed between the solvent metering pump, the batching control module, the prepolymerization control module and the solvent feed control valve by electrical signals; The additive metering pump Ⅰ and the additive feed control valve Ⅰ are interlocked by electrical signals, and a control loop is formed between the additive metering pump Ⅰ, the batching control module, the prepolymerization control module and the additive feed control valve Ⅰ through electrical signals; The additive metering pump II and the additive feed control valve II are interlocked by electrical signals, and a control loop is formed between the additive metering pump II, the batching control module, the polymerization control module and the additive feed control valve II by electrical signals; The temperature sensor Ⅰ, the temperature sensor Ⅱ, the heat transfer material feed control valve, the heat transfer material discharge control valve, the heat transfer oil feed control valve Ⅰ and the heat transfer oil discharge control valve Ⅰ are interlocked through electrical signals, and the temperature sensor Ⅰ, the temperature sensor Ⅱ, the prepolymerization control module, the heat transfer material feed control valve, the heat transfer material discharge control valve, the heat transfer oil feed control valve Ⅰ and the heat transfer oil discharge control valve Ⅰ form a control loop through electrical signals; The temperature sensor III, the temperature sensor IV, the thermal oil feed control valve II, the thermal oil discharge control valve II and the cold oil feed control valve are interlocked through electrical signals, and a control loop is formed between the temperature sensor III, the temperature sensor IV, the polymerization control module, the thermal oil feed control valve II, the thermal oil discharge control valve II and the cold oil feed control valve through electrical signals.

[0010] Furthermore, the equipment group also includes a frequency converter arranged on the stirring device, the stirring device is connected to the stirring motor through the frequency converter, and a stirring speed control path is formed between the prepolymerization control module, the frequency converter and the stirring motor.

[0011] In addition, the DCS controller also includes a deashing and separation control template, a waste material processing module and an alarm control module. The deashing and separation control module is connected to the polymerization control module, the waste material processing module is connected to the deashing and separation control module, and the alarm control module is connected to the batching control module, the pre-polymerization control module, the polymerization control module, the deashing and separation control template (86) and the waste material processing module. In the present technical solution, the number of metering pumps, sensors, control valves, etc. on the corresponding pipelines and / or equipment can be further limited according to actual needs.

[0012] The positional relationships involved in this technical solution, such as "back of the workstation", "between", "on", "inside", "above", "below", "bottom", "top", "from bottom to top", "one end", "the other end", and "lower", are defined according to the situations under actual usage conditions and are conventional terms in this technical field, and are also conventional terms used by technical personnel in this field in actual use.

[0013] In the description of the present technical solution, it should be noted that, unless otherwise clearly specified and limited, "setting" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0014] The beneficial technical effects brought about by adopting this technical solution are: The present invention provides a production process, system and control system for continuously preparing methacrylic acid polymers, wherein, according to the corresponding production process, production system and control system, effective controllability of polymerization conversion rate and reaction heat is guaranteed, and a dynamic balance between polymerization conversion rate and reaction heat is maintained, and finally stability, orderliness and controllability of the methacrylic acid polymer production process are achieved, so as to meet the needs of industrialized, automated and economical mass production, and provide an effective prerequisite for the processing and production of new materials; at the same time, optical-grade polymer products can be produced to meet actual needs; In the present invention, firstly, by using solution vaporization (bubble point material) to transfer heat in a fully mixed reactor, it is specially set that: the vaporization temperature of the heat transfer material under normal pressure is 5-10°C higher than the set reaction temperature in the fully mixed reactor, and the feed temperature of the heat transfer material is 5-10°C lower than the set reaction temperature; secondly, a segmented tubular reactor is proposed, that is, multiple reaction sections are concentrated in the tubular reactor, and concentrated and efficient heat exchange is achieved through this structure, so that the temperature of the polymerization reaction node is precisely controlled; at the same time, auxiliary agents (such as initiators and chain transfer agents) are added at multiple key nodes, and the added amounts are optimized and combined; finally, the conversion rate and degree of polymerization of each reaction node are controlled within a narrow range, and precise control is achieved to ensure that the polymerization reaction process is safe, continuous and controllable; In addition, concentrating the polymerization reaction in a shell-and-tube reactor can not only reduce the use of power equipment, but also achieve high-intensity heat exchange through the shell-and-tube heat exchange structure, and use the heat of the previous reaction zone for the next reaction zone, thereby achieving energy coupling, reducing energy consumption, and so on. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a flow chart of the production process of the present invention; Figure 2 A schematic diagram of the working principle of the production system of the present invention; Figure 3 The equipment structure block diagram of the production system in the present invention; Figure 4 A schematic structural diagram of a segmented tubular reactor according to the present invention; Figure 5 A schematic diagram of the control principle of the control system in the present invention; Figure 6 It is a logical connection diagram of the control system in the present invention; Figure 7 It is a structural block diagram of a DCS controller in the control system of the present invention; In the figure, 1, a mixing buffer tank, 100, an alkyl methacrylate monomer feed pipe, 101, an alkyl methacrylate monomer metering tank, 102, an alkyl acrylate monomer feed pipe, 103, an alkyl acrylate monomer metering tank, 104, a (meth) cyclic acrylate monomer feed pipe, 105, a (meth) cyclic acrylate monomer metering tank, 106, a protective gas inlet pipe I, 107, a displacement gas outlet pipe, 108, a mixed material delivery pipe; 2. Fully mixed reactor, 200. Solvent feed pipe, 201. Solvent metering tank, 202. Auxiliary agent feed pipe I, 203. Auxiliary agent metering tank, 204. Protective gas inlet pipe II, 205. Three-blade stirring mechanism, 206. Temperature control coil, 207. Heat transfer material inlet pipe, 208. Heat transfer material discharge pipe, 209. Prepolymerization reaction system delivery pipe, 210. Heating jacket, 211. Heat transfer oil inlet pipe I, 212. Heat transfer oil outlet pipe I; 3. Segmented shell-and-tube reactor, 300, shell, 301, mixed flow unit, 302, shell-and-tube reaction unit, 303, mixed flow cavity, 304, shell and tube, 305, temperature control cavity, 306, auxiliary agent feed pipe II, 307, heat transfer oil inlet pipe II, 308, heat transfer oil outlet pipe II, 309, heat transfer oil connecting pipe, 310, reactant delivery pipe, 311, cold oil feed pipe; 4. Integrated deliming and strip extrusion machine; 5. Protect gas storage tanks; 6. Methacrylic acid polymer storage tank; 7. Monomer recovery device, 700, recycling pipe; 8. DCS controller, 81. batching control module, 82. pre-polymerization control module, 83. polymerization control module, 84. waste material processing module, 85. alarm control module, 86. ash separation control template; 9. Methacrylate alkyl ester monomer feed control valve, 10. Methacrylate alkyl ester monomer metering pump, 11. Acrylate alkyl ester monomer feed control valve, 12. Acrylate alkyl ester monomer metering pump, 13. (Meth) acrylate cyclic ester monomer feed control valve, 14. (Meth) acrylate cyclic ester monomer metering pump, 15. Protective gas feed control valve I, 16. Oxygen content analyzer, 17. Pressure sensor I, 18. Temperature sensor I, 19. Mixture delivery pump, 20. Solvent feed control valve, 22. Solvent metering pump, 23. Auxiliary agent feed control valve I, 24. Auxiliary agent metering pump I, 25 , protective gas feed control valve II, 26, heat transfer material feed control valve, 27, heat transfer material discharge control valve, 28, pressure sensor II, 29, temperature sensor II, 30, prepolymerization reaction system delivery pump, 31, heat transfer oil feed control valve I, 32, heat transfer oil discharge control valve I, 33, auxiliary agent feed control valve II, 34, auxiliary agent metering pump II, 35, heat transfer oil feed control valve II, 36, heat transfer oil discharge control valve II, 37, cold oil feed control valve, 38, reactant delivery pump, 39, pressure sensor III, 40, temperature sensor III, 41, pressure sensor IV, 42, temperature sensor IV. DETAILED DESCRIPTION

[0016] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0017] Example 1 This embodiment provides: a production process for continuously preparing methacrylic acid polymers, comprising the following steps: S1 Batching: Add the raw materials of alkyl methacrylate monomer, alkyl acrylate monomer and (meth) acrylate cyclic ester monomer into the mixing buffer tank until the total volume of the raw materials accounts for 2 / 3 to 4 / 5 of the volume of the mixing buffer tank, then stop adding the raw materials; mix the raw materials evenly to obtain a mixture; then, introduce protective gas (such as high-purity Ar or N 2 ), to replace the gas in the mixing buffer tank; Among them, the mixing buffer tank is controlled such that: the oxygen content in each monomer raw material is ≤1ppm; the pressure is 20-50KPa, and the temperature is 20-50℃; S2 prepolymerization: adding the gas-substituted mixture obtained in step S1, the solvent and the auxiliary agent into a fully mixed reactor, heating the fully mixed reactor to 90-140°C at a rate of 1-3°C / min; then, staying for 30-240 min to obtain a prepolymerization reaction system; Among them, the fully mixed reactor is controlled: the difference between the actual maximum temperature of the prepolymerization reaction and the set temperature is not higher than 10°C, the pressure is 0.5-2.0MPa, the oxygen content is ≤2ppm, and the conversion rate of the alkyl methacrylate monomer is 30-50%; S3 polymerization: the prepolymerization reaction system obtained in step S2 is introduced into a segmented shell-and-tube reactor, and the polymerization temperature in the segmented shell-and-tube reactor is controlled to be 140-200° C., the pressure is 1.5-3.5 MPa, and the moving speed of the material in the shell-and-tube reactor is 0.001-0.1 m / s, and finally, a slurry product is obtained; S4 deashing and separation: the slurry product obtained in step S3 is introduced into a deashing and extruding integrated machine for deashing and separation to obtain a polymer material and waste materials including unreacted monomers, solvents, oligomers and additives.

[0018] Example 2 On the basis of Example 1, this example further limits the amount and type of raw materials, additives, solvents, etc. to be added, so as to better implement the present invention and further illustrate the technical solution.

[0019] In step S1, based on the sum of the weight of the monomer raw materials being 100%, the content of the alkyl methacrylate monomer is 68-95%, the content of the alkyl acrylate monomer is 3-30%, and the content of the (meth)acrylic acid cyclic ester monomer is 2-15%; In step S2, the amount of solvent added is 1-10% of the total amount of the monomer raw material, and the amount of auxiliary agent added is 0.05-0.3% of the total amount of the monomer raw material; In step S3, the amount of the additive added again is 0.04-0.55%; Among them, before batching, the alkyl methacrylate monomer, the alkyl acrylate monomer and the (meth)acrylate cyclic ester monomer are all refined to remove the polymerization inhibitor, and then can enter the mixing buffer tank under the action of the pipeline mixed gas.

[0020] Among them, for each monomer raw material: The alkyl methacrylate monomer includes one or a combination of any two or more of methyl methacrylate, ethyl methacrylate, propyl methacrylate and isooctyl (meth)acrylate; The alkyl acrylate monomer includes one or a combination of any two or more of methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate and isooctyl acrylate; The (meth)acrylic acid cyclic ester monomer includes one or a combination of any two or more of cyclohexyl methacrylate, isobornyl acrylate, isobornyl methacrylate and benzyl methacrylate; For solvents: including one or a combination of any two or more of methanol, ethanol, benzene, toluene, methyl acetate and ethyl acetate; Preferably, the material includes methyl methacrylate with a content of 80-97%, methyl acrylate with a content of 1-10%, isobornyl acrylate with a content of 1-8%, and methanol with a content of 1-5%; As another preferred embodiment, the material includes methyl methacrylate with a content of 80-97%, ethyl acrylate with a content of 1-10%, isobornyl methacrylate with a content of 1-7%, and methanol with a content of 1-5%; As another preferred embodiment, the material includes methyl methacrylate with a content of 80-97%, isooctyl acrylate with a content of 1-5%, benzyl methacrylate with a content of 1-5%, and ethanol with a content of 1-5%; As another preferred embodiment, the material includes methyl methacrylate with a content of 80-95%, propyl acrylate with a content of 5-10%, cyclohexyl methacrylate with a content of 2-7%, and ethanol with a content of 2-5%; As another preferred embodiment, the material includes methyl methacrylate with a content of 75-95%, isooctyl methacrylate with a content of 2-5%, isobornyl acrylate with a content of 1-3%, and methyl acetate with a content of 2-5%; For auxiliary agents: including initiators and chain transfer agents; Wherein, the initiator is an azo compound or an organic peroxide compound. Wherein, the azo compound is preferably one of azobisisobutyronitrile and azobisisoheptanenitrile or a combination of the two; The organic peroxide compound is preferably one or a combination of any two or more of dibenzoyl peroxide, dodecyl peroxide, di-tert-butyl peroxide, diisopropyl peroxide and diisopropyl peroxydicarbonate; In the fully mixed reactor, the azo compound is preferably one of azobisisobutyronitrile, dibenzoyl peroxide, ditert-butyl peroxide and azobisisoheptylonitrile or a combination of any two or more thereof, and the amount of initiator added is 0.005-0.03% of the total amount of the monomer raw material; in the segmented tubular reactor, the first and second reaction zones are preferably one of dodecyl peroxide, diisopropyl peroxide and diisopropyl peroxydicarbonate or a combination of any two or more thereof, and the amount of initiator added is 0.005-0.02% of the total amount of the monomer raw material; the third reaction zone is preferably one of azobisisoheptylonitrile and azobisisobutyronitrile or a combination of the two, and the amount of initiator added is 0.001-0.01% of the total amount of the monomer raw material; The chain transfer agent is one of benzyl dithiobenzoate, cumyl dithiobenzoate, phenethyl dithiobenzoate and 2,4-diphenyl-4-methyl-1-pentene, or a combination of any two or more thereof; In a fully mixed reactor, the amount of chain transfer agent added is preferably 0.05-0.3% of the total amount of monomer raw materials; in a segmented tubular reactor, the amount of chain transfer agent added to the first reaction zone is 0.02-0.2% of the total amount of monomer raw materials, the amount of chain transfer agent added to the second reaction zone is 0.01-0.2% of the total amount of monomer raw materials, and the amount of chain transfer agent added to the third reaction zone is 0.01-0.15% of the total amount of monomer raw materials.

[0021] Taking the sum of the mass of the three monomer esters as 100%, the total amount of the initiator added is 0.01-0.1%, and the total amount of the chain transfer agent added is 0.01-1.0%. In specific production, the (meth) acrylate alkyl ester, initiator and transfer agent can also be mixed in isolation from air and then injected into the material at the feed port.

[0022] Example 3 On the basis of Examples 1-2, the process control involved in the segmented shell-and-tube reactor of this Example is further limited to further illustrate the present invention.

[0023] Among them, the segmented shell-and-tube reactor includes a first reaction zone, a second reaction zone and a third reaction zone which are distributed from bottom to top, and the temperature relationship in the three reaction zones is: 7°C ≤ temperature of the second reaction zone - temperature of the first reaction zone = temperature of the third reaction zone - temperature of the second reaction zone ≤ 20°C.

[0024] Control the first stage reaction zone: the amount of the additive added again is 0.02-0.2% of the total amount of the monomer raw material, the material stays for 20-100 minutes, the temperature is 140-155°C, and the total conversion rate of the alkyl methacrylate monomer is accumulated to 40-55%; Control the second stage reaction zone: the amount of the additive added again is 0.01-0.2% of the total amount of the monomer raw material, the material stays for 10-80 minutes, the temperature is 155-175°C, and the total conversion rate of the alkyl methacrylate monomer is accumulated to 50-65%; Control the third reaction zone: the amount of the additive added again is 0.01-0.15% of the total amount of the monomer raw material, the material stays for 5-60 minutes, the temperature is 175-200°C, and the total conversion rate of the alkyl methacrylate monomer is accumulated to 60-75%.

[0025] Example 4 On the basis of Examples 1-3, the process control and waste treatment involved in the deashing and separation process of this Example are further limited to further illustrate the present invention.

[0026] At a temperature of 200-280°C and an absolute pressure of 10-40KPa, deashing and separation is carried out for 10-30 minutes.

[0027] The waste materials including unreacted monomers, solvents, oligomers and additives are introduced into the monomer recovery device, and after separation, the recovered unreacted monomers are recycled to the batching process.

[0028] Example 5 On the basis of Examples 1-4, this embodiment provides a corresponding production system, which specifically includes: a mixing buffer tank 1, a fully mixed reactor 2, a segmented tubular reactor 3 and a deashing and extruding integrated machine 4; The mixing buffer tank 1 is connected to an alkyl methacrylate monomer metering tank 101 through an alkyl methacrylate monomer feed pipe 100, is also connected to an alkyl acrylate monomer metering tank 103 through an alkyl acrylate monomer feed pipe 102, is also connected to a (meth)acrylate cyclic ester monomer metering tank 105 through a (meth)acrylate cyclic ester monomer feed pipe 104, and is also connected to a protective gas storage tank 5 through a protective gas inlet pipe I 106; the upper displacement gas outlet of the mixing buffer tank 1 is connected to a displacement gas outlet pipe 107; the upper discharge port of the mixing buffer tank 1 is connected to the full mixing reactor 2 through a mixed material delivery pipe 108; The fully mixed reactor 2 is arranged at the rear side of the station of the mixing buffer tank 1. The fully mixed reactor 2 is connected to the solvent metering tank 201 through the solvent feeding pipe 200, and is also connected to the auxiliary agent metering tank 203 through the auxiliary agent feeding pipe I 202, and is also connected to the protective gas storage tank 5 through the protective gas inlet pipe II 204; the upper discharge port of the fully mixed reactor 2 is connected to the segmented tubular reactor 3 through the prepolymerization reaction system delivery pipe 209; The segmented tubular reactor 3 is arranged at the rear side of the station of the fully mixed reactor 2. The segmented tubular reactor 3 includes a shell 300 and at least two mixing units 301 and at least two tubular reaction units 302 arranged in the shell 300. The mixing units 301 and the tubular reaction units 302 are arranged at intervals and are distributed upward in sequence; a feed port is provided on the bottom mixing unit 301, and a discharge port is provided on the top tubular reaction unit 302. A continuous passage for polymerization reaction is formed between the feed port, the mixing unit 301, the tubular reaction unit 302 and the discharge port; the discharge port on the segmented tubular reactor 3 is connected to the deashing and extruding integrated machine 4 through a reactant conveying pipe 310; The deashing and extruding integrated machine 4 is arranged at the rear side of the station of the segmented tubular reactor 3, the polymer outlet on the deashing and extruding integrated machine 4 is connected to the methacrylic acid polymer storage tank 6, the waste outlet on the deashing and extruding integrated machine 4 is connected to the monomer recovery device 7, and the monomer outlet on the monomer recovery device 7 is connected to the mixing buffer tank 1 through the recycling pipe 700; A continuous passage for the production of methacrylic acid series polymer is formed between the mixing buffer tank 1, the fully mixed reactor 2, the segmented tubular reactor 3, the deashing and extruding integrated machine 4 and the methacrylic acid series polymer storage tank 6.

[0029] Among them, a stirring device is provided in the fully mixed reactor 2, and a temperature control coil 206 is provided on the stirring device. One end of the temperature control coil 206 is connected to a heat transfer material inlet pipe 207, and the other end is connected to a heat transfer material discharge pipe 208; a three-paddle stirring mechanism 205 is provided at the lower part of the stirring device, and the three-paddle stirring mechanism 205 includes a blade assembly I, a blade assembly II and a blade assembly III distributed from bottom to top, and the blades in the blade assembly I are twisted clockwise by 35 to 45°C, the blades in the blade assembly II are twisted counterclockwise by 35 to 45°C, and the blades in the blade assembly III are twisted clockwise by 35 to 45°C; A heating jacket 210 is provided on the outer side of the fully mixed reactor 2. The heat source in the heating jacket 210 is heat transfer oil. The inlet of the heating jacket 210 is connected to a heat transfer oil inlet pipe I 211, and the outlet of the heating jacket 210 is connected to a heat transfer oil outlet pipe I 212. The heat transfer material in the temperature control coil 206 is a liquid feed. The vaporization temperature of the heat transfer material under normal pressure is 5-10°C higher than the set reaction temperature in the fully mixed reactor 2, and the feed temperature of the heat transfer material is 5-10°C lower than the set reaction temperature.

[0030] Each flow mixing unit 301 is connected to an auxiliary agent feeding pipe II 306 , and the flow mixing unit 301 includes a flow mixing cavity 303 connected to the auxiliary agent feeding pipe II 306 ; The bottom tube-in-tube reaction unit 302 is connected to a heat transfer oil inlet pipe II 307, the top tube-in-tube reaction unit 302 is connected to a heat transfer oil outlet pipe II 308, and the upper-level tube-in-tube reaction unit 302 is connected to the lower-level tube-in-tube reaction unit 302 via a heat transfer oil connecting pipe 309. The tube-in-tube reaction unit 302 includes a longitudinally arranged tube-in-tube 304, and a temperature control cavity 305 between the tube-in-tube 304 and the shell 300 is used to accommodate the heat transfer oil, and the temperature control cavity 305 is connected to a cold oil feed pipe 311. For the moving speed u (m / s) of the material in each zone, the residence time t (s) of each zone, and the length L (m) of each zone, the inner diameter D (m) of the segmented shell-and-tube reactor 3 satisfies the following conditions: t=L / u, when 0.05≤D≤0.2, 0.01*D≤u*1s<0.05*D; when 0.2<D≤0.5, 0.01*D≤u*1s<0.025*D.

[0031] Example 6 On the basis of Examples 1-5, this embodiment provides a corresponding control system, which is arranged in a production system capable of continuously preparing methacrylic acid-based polymers, and the control system comprises a DCS controller 8, wherein the DCS controller 8 is connected to a human-machine interface via a data input interface, the DCS controller 8 is connected to a data acquisition unit via a data feedback interface, and the DCS controller 8 is connected to an execution unit via a data output interface; DCS controller 8: includes batching control module 81, prepolymerization control module 82 and polymerization control module 83; Data acquisition unit: set in the production system of methacrylic acid series polymer, the data acquisition unit includes a sensor group used for data acquisition and transmission in the production process of methacrylic acid series polymer; Execution unit: set in the production system of methacrylic acid polymer, the execution unit includes a group of equipment for preparing and regulating methacrylic acid polymer.

[0032] The sensor group includes an alkyl methacrylate monomer metering pump 10 provided on an alkyl methacrylate monomer feed pipe 100, an alkyl acrylate monomer metering pump 12 provided on an alkyl acrylate monomer feed pipe 102, a (meth)acrylate cyclic ester monomer metering pump 14 provided on a (meth)acrylate cyclic ester monomer feed pipe 104, an oxygen content analyzer 16 provided on a displacement gas outlet pipe 107, a solvent metering pump 22 provided on a solvent feed pipe 200, an auxiliary agent metering pump I24 provided on an auxiliary agent feed pipe I202, and an auxiliary agent metering pump II34 provided on an auxiliary agent feed pipe II306. The alkyl methacrylate monomer metering pump 10, the alkyl acrylate monomer metering pump 12, the (meth)acrylate cyclic ester monomer metering pump 14, the oxygen content analyzer 16, the solvent metering pump 22, the auxiliary agent metering pump I24, and the auxiliary agent metering pump II34 are all connected to the batching control module 81; The sensor group also includes a pressure sensor Ⅰ17 and a temperature sensor Ⅰ18 provided on the mixing buffer tank 1, and a pressure sensor Ⅱ28 and a temperature sensor Ⅱ29 provided on the fully mixed reactor 2. The pressure sensor Ⅰ17, the temperature sensor Ⅰ18, the pressure sensor Ⅱ28 and the temperature sensor Ⅱ29 are all connected to the prepolymerization control module 82; the prepolymerization control module 82 is connected to the solvent metering pump 22 and the auxiliary agent metering pump Ⅰ24; The sensor group also includes a pressure sensor III39 and a temperature sensor III40 provided on the mixed flow unit 301, and a pressure sensor IV41 and a temperature sensor IV42 provided on the tube-in-tube reaction unit 302. The pressure sensor III39, the temperature sensor III40, the pressure sensor IV41 and the temperature sensor IV42 are all connected to the polymerization control module 83; the polymerization control module 83 is connected to the additive metering pump II34.

[0033] The equipment group includes an alkyl methacrylate monomer feed control valve 9 provided on an alkyl methacrylate monomer feed pipe 100, an alkyl acrylate monomer feed control valve 11 provided on an alkyl acrylate monomer feed pipe 102, a (meth)acrylate cyclic ester monomer feed control valve 13 provided on a (meth)acrylate cyclic ester monomer feed pipe 104, a protective gas feed control valve I 15 provided on a protective gas feed pipe I 106, and a solvent feed control valve I 16 provided on a solvent feed pipe 200. The control valve 20, the auxiliary agent feed control valve I23 provided on the auxiliary agent feed pipe I202 and the auxiliary agent feed control valve II33 provided on the auxiliary agent feed pipe II306, the methacrylate alkyl ester monomer feed control valve 9, the acrylate alkyl ester monomer feed control valve 11, the (meth) acrylate cyclic ester monomer feed control valve 13, the protective gas feed control valve I15, the solvent feed control valve 20, the auxiliary agent feed control valve I23 and the auxiliary agent feed control valve II33 are all connected to the batching control module 81; The equipment group also includes a protective gas feed control valve II25 arranged on the protective gas inlet pipe II, a heat transfer material feed control valve 26 arranged on the heat transfer material inlet pipe 207, a heat transfer material discharge control valve 27 arranged on the heat transfer material discharge pipe 208, a heat transfer oil feed control valve I31 arranged on the heat transfer oil inlet pipe I211, and a heat transfer oil discharge control valve I32 arranged on the heat transfer oil outlet pipe I212. The protective gas feed control valve II25, the heat transfer material feed control valve 26, the heat transfer material discharge control valve 27, the heat transfer oil feed control valve I31, and the heat transfer oil discharge control valve I32 are all connected to the prepolymerization control module 82; the prepolymerization control module 82 is connected to the solvent feed control valve 20 and the auxiliary agent feed control valve I23; The equipment group also includes a heat-conducting oil feed control valve II35 provided on the heat-conducting oil inlet pipe II307, a heat-conducting oil discharge control valve II36 provided on the heat-conducting oil outlet pipe II308, and a cold oil feed control valve 37 provided on the cold oil feed pipe 311. The heat-conducting oil feed control valve II35, the heat-conducting oil discharge control valve II36, and the cold oil feed control valve 37 are all connected to the polymerization control module 83; the polymerization control module 83 is connected to the auxiliary agent feed control valve II33; Among them, the alkyl methacrylate monomer metering pump 10 and the alkyl methacrylate monomer feed control valve 9 are interlocked by electrical signals, and the alkyl methacrylate monomer metering pump 10, the batching control module 81 and the alkyl methacrylate monomer feed control valve 9 form a control loop through electrical signals; The alkyl acrylate monomer metering pump 12 and the alkyl acrylate monomer feed control valve 11 are interlocked by electrical signals, and a control loop is formed between the alkyl acrylate monomer metering pump 12, the batching control module 81 and the alkyl acrylate monomer feed control valve 11 through electrical signals; The (meth)acrylic acid cyclic ester monomer metering pump 14 and the (meth)acrylic acid cyclic ester monomer feed control valve 13 are interlocked by electrical signals, and the (meth)acrylic acid cyclic ester monomer metering pump 14, the batching control module 81 and the (meth)acrylic acid cyclic ester monomer feed control valve 13 form a control loop by electrical signals; The solvent metering pump 22 and the solvent feed control valve 20 are interlocked by electrical signals, and a control loop is formed between the solvent metering pump 22, the batching control module 81, the prepolymerization control module 82 and the solvent feed control valve 20 by electrical signals; The additive metering pump Ⅰ24 and the additive feed control valve Ⅰ23 are interlocked by electrical signals, and a control loop is formed between the additive metering pump Ⅰ24, the batching control module 81, the prepolymerization control module 82 and the additive feed control valve Ⅰ23 through electrical signals; The additive metering pump II34 and the additive feed control valve II33 are interlocked by electrical signals, and a control loop is formed between the additive metering pump II34, the batching control module 81, the polymerization control module 83 and the additive feed control valve II33 by electrical signals; The temperature sensor Ⅰ18, the temperature sensor Ⅱ29, the heat transfer material feed control valve 26, the heat transfer material discharge control valve 27, the heat transfer oil feed control valve Ⅰ31 and the heat transfer oil discharge control valve Ⅰ32 are interlocked by electrical signals, and the temperature sensor Ⅰ18, the temperature sensor Ⅱ29, the prepolymerization control module 82, the heat transfer material feed control valve 26, the heat transfer material discharge control valve 27, the heat transfer oil feed control valve Ⅰ31 and the heat transfer oil discharge control valve Ⅰ32 form a control loop through electrical signals; The temperature sensor III 40, the temperature sensor IV 42, the thermal oil feed control valve II 35, the thermal oil discharge control valve II 36 and the cold oil feed control valve 37 are interlocked through electrical signals, and a control loop is formed between the temperature sensor III 40, the temperature sensor IV 42, the polymerization control module 83, the thermal oil feed control valve II 35, the thermal oil discharge control valve II 36 and the cold oil feed control valve 37 through electrical signals.

[0034] In addition, the DCS controller 8 further includes a deashing and separation control template 86, a waste material processing module 84 and an alarm control module 85, the deashing and separation control module is connected to the polymerization control module 83, the waste material processing module 84 is connected to the deashing and separation control module, and the alarm control module 85 is connected to the batching control module 81, the pre-polymerization control module 82, the polymerization control module 83, the deashing and separation control template 86 (86) and the waste material processing module 84; According to actual needs, set metering pumps, sensors, control valves, etc. on corresponding pipelines and / or equipment.

[0035] As a specific implementation method, the work process involved is as follows: The monomer raw materials are fed into the mixing buffer tank 1 through the corresponding feed pipe, and the corresponding metering pumps, temperature sensors, pressure sensors, etc. detect and feedback signals to the DCS controller 8, ultimately achieving high-precision batching, while facilitating subsequent prepolymerization and polymerization reactions. For example, when the pipeline detection temperature is too high (>80°C) due to external reasons, the cooling system (spraying system or cooling water system) of the monomer raw material storage tank can be started accordingly; and when the monomer raw material detection temperature drops below 50°C, the cooling process is stopped; Generally, the three monomer raw materials are fed into the mixing buffer tank 1 through the feed pipe, and the feeding is stopped when the liquid level in the mixing buffer tank 1 reaches 2 / 3 or 4 / 5. After reaching the specified liquid level, the gas replacement control valve on the replacement gas outlet pipe 107 connected to the mixing buffer tank 1 is opened, and high-purity nitrogen (or argon) is introduced to replace the air brought into the mixing buffer tank 1 until the oxygen content in the mixing buffer tank 1 is reduced to 1ppm, and the replacement is stopped; While nitrogen is being replaced in the mixing buffer tank 1, the pipelines in the main process area, the fully mixed reactor 2 and the segmented tubular reactor 3 are all replaced with protective gas until the oxygen content of the gas after replacement is detected to be below 2 ppm; Subsequently, the mixed raw materials are delivered to the fully mixed reactor 2 through the mixed material delivery pump 19, and at the same time, the raw materials dissolved in the solvent and the auxiliary agent pipeline (or the auxiliary agent can be dissolved in the solvent first and then added) are delivered to the fully mixed reactor 2. Here, the feed pipe involved extends to the lower part of the fully mixed reactor 2 and is close to the fully mixed reactor 2. The feed pipe is made of 316L. Corresponding temperature sensors, pressure sensors and flow detectors can be set on the mixed material delivery pipe 108, the solvent feed pipe 200 and the auxiliary agent feed pipe I 202 to detect and feedback signals; by controlling the delivery speed and delivery time of the mixed material, solvent and auxiliary agent, the ratio between the auxiliary agent, solvent and monomer raw materials in the fully mixed reactor 2 is regulated. In the fully mixed reactor 2, the stirring device involved is electromagnetically driven. The temperature measuring point on the fully mixed reactor 2 is protected by a stainless steel jacket. The lowest point is located at 4 / 5 of the bottom of the fully mixed reactor 2, 3 cm away from the wall of the fully mixed reactor 2. The fully mixed reactor 2 is heated by the heat transfer oil in the outer heating jacket 210. A PID interlocking control is formed between the temperature point of the heat transfer oil and the temperature point of the fully mixed reactor 2 to keep the temperature rise of the material in the fully mixed reactor 2 in a controllable state. A pressure detection point is provided on the upper part of the reactor cover of the fully mixed reactor 2, with a field display instrument and a signal line; After the prepolymerization reaction is completed, the discharge valve is opened, and compressed high-purity inert gas (protective gas) is introduced to press the prepolymerization reaction system after the reaction into the prepolymerization reaction system delivery pipe 209 (product discharge pipeline), and then, it is pumped into the segmented tubular reactor 3 through the prepolymerization reaction system delivery pump 30, and a flow meter, a temperature sensor, a pressure sensor and a signal line are arranged on the subsequent pipeline of the prepolymerization reaction system delivery pump 30; the material continues to react in each segment of the tubular reaction unit 302, and at the same time, different types of additives are added to each segment of the mixed flow unit 301, and the additive injection speed at the additive feed port on each segment of the mixed flow unit 301 can be controlled by a needle injection pump, and the injection speed is controlled to form a positive feedback proportional relationship with the flow meter on the prepolymerization reaction system delivery pipe 209, and the proportional coefficient can be set before the equipment is operated. In addition, temperature and pressure detection points are distributed on each tube-in-tube reaction unit 302, and the temperature and pressure detection points are linked with the heat transfer oil inlet pipe II 307, the heat transfer oil outlet pipe II 308 and the cold oil feed pipe 311 system, so as to accurately control the temperature and pressure in the segmented tube-in-tube reactor 3, and realize the control of reaction heat and conversion rate; After the material passes through the segmented tubular reactor 3, the obtained slurry product is transported to the deashing and extruding integrated machine 4 through the reactant delivery pipe 310 and the reactant delivery pump 38. The reactant delivery pipe 310 may also be provided with a flow meter, a temperature sensor, a pressure sensor and a signal line; the slurry product after the polymerization reaction enters the deashing and extruding integrated machine 4, and multiple temperature and pressure detection points and signal feedback lines may be evenly distributed before and after the deashing and extruding integrated machine 4, so as to ensure that the temperature and pressure of the deashing machine are within a high-precision controllable range; the high-temperature gas discharged by deashing and separation enters the subsequent separation device after cooling and heat exchange, and the monomer components are recovered. After analysis, they can be mixed with the corresponding monomer raw materials according to the proportion of content and enter the mixing buffer tank 1. The polymer material discharged by deashing and separation can be subsequently processed.

[0036] Example 7 This embodiment provides an optical grade PMMA production process, which is as follows: (1) Based on the total weight of the raw monomers and the solvent as 100%, 92% by weight of methyl methacrylate, 3% by weight of methyl acrylate and 5% by weight of isobornyl acrylate were mixed evenly in a mixing buffer tank, and then high-purity Ar was introduced for displacement until the oxygen content was ≤1ppm; then, 3% of methanol, 150ppm of dibenzoyl peroxide and 0.1% of benzyl dithiobenzoate were mixed evenly in a pipeline mixer, and then added into a fully mixed reactor with a stirring device and made of 345R material, the wall surface of the fully mixed reactor was polished super-bright surface, and a heat transfer oil heating system and a cooling heat transfer system were used; the stirring speed was controlled to be 90r / min, the bubble point temperature of the heat transfer material in the temperature control coil in the fully mixed reactor was 138°C, the reaction temperature was 130°C, the reaction residence time was 100min, the pressure was controlled at 0.9 MPa, and a prepolymerization reaction was carried out, and the methyl methacrylate conversion rate was 35%; (2) The prepolymerization reaction system discharged from the fully mixed reactor is introduced into three independent segmented tubular reactors, wherein the three independent segmented tubular reactors include a first mixing unit, a first tubular reaction unit, a second mixing unit, a second tubular reaction unit, a third mixing unit and a third tubular reaction unit arranged in sequence from bottom to top. The segmented tubular reactor has an inner diameter of 0.2 m, a number of 4 reactors, and a pressure of 2.5 MPa in the entire shell; At the first mixed flow unit, 180ppm of di-tert-butyl peroxide and 0.15% of 2,4-diphenyl-4-methyl-1-pentene were added through a nozzle, and the nozzle rotation speed was 50r / min; the length of the reaction zone in the first tube-by-tube reaction unit was 9m, the retention time of the material in the first tube-by-tube reaction unit was 30min, the reaction temperature was 145°C, and after passing through the reaction zone, the conversion rate of methyl methacrylate was 58%; At the second mixed flow unit, 220ppm of azobisisobutyronitrile and 0.05% of cumyl dithiobenzoate were added through a nozzle, and the nozzle rotation speed was 40r / min; the length of the reaction zone in the second tube-by-tube reaction unit was 7.5m, the retention time of the material in the second tube-by-tube reaction unit was 25min, the reaction temperature was 162°C, and after passing through the reaction zone, the conversion rate of methyl methacrylate was 65%; At the third mixed flow unit, 120ppm of azobisisoheptanenitrile and 0.02% of 2,4-diphenyl-4-methyl-1-pentene were added through a nozzle, and the nozzle rotation speed was 20r / min; the length of the reaction zone in the third tubular reaction unit was 6m, the retention time of the material in the third tubular reaction unit was 20min, the reaction temperature was 179°C, and after passing through the reaction zone, the conversion rate of methyl methacrylate was 74%, and a slurry material was obtained; (3) The slurry material discharged from the segmented tubular reactor is passed into the deashing extruder for deashing at a temperature of 275°C and an absolute pressure of 40 KPa. The unreacted monomers, solvents, oligomers, and trace amounts of chain transfer agents in the material are gasified and separated from the polymer compound. The gas enters the monomer recovery device. The polymer material can be extruded through the extruder and granulated to obtain PMMA particles, etc. The material stays in the deashing extruder for 20 min.

[0037] According to the standard ISO13468, the optical properties of PMMA particles are tested, and it can be known that the total light transmittance coefficient of the PMMA particles is greater than 92%.

[0038] Example 8 This embodiment provides an optical grade PMMA production process, which is as follows: (1) Based on the total weight of the raw material monomers and the solvent as 100%, 95% by weight of methyl methacrylate, 4% by weight of benzyl methacrylate and 1% by weight of benzyl methacrylate were mixed evenly in a mixing buffer tank, and then high-purity N 2 The mixture was replaced until the oxygen content was ≤1ppm; then, 2% toluene, 100ppm dibenzoyl peroxide and 0.2% phenethyl dithiobenzoate were mixed evenly in a pipeline mixer, and then added into a fully mixed reactor with a stirring device and made of 304SS. The wall of the fully mixed reactor was polished and super-smooth. A heat transfer oil heating system and a cooling heat transfer system were used. The stirring speed was controlled to be 60r / min, the bubble point temperature of the heat transfer material in the temperature control coil in the fully mixed reactor was 145°C, the reaction temperature was 138°C, the reaction residence time was 120min, the pressure was controlled at 1.2MPa, and a prepolymerization reaction was carried out. The conversion rate of methyl methacrylate was 34%. (2) The prepolymerization reaction system discharged from the fully mixed reactor is introduced into three independent segmented tubular reactors (made of 304SS stainless steel). The three independent segmented tubular reactors include a first mixing unit, a first tubular reaction unit, a second mixing unit, a second tubular reaction unit, a third mixing unit and a third tubular reaction unit arranged from bottom to top. The inner diameter of the segmented tubular reactor is 0.4m, the number is 2, and the pressure in the entire shell is 3.0MPa; At the first mixed flow unit, 200ppm of diisopropylbenzene peroxide, 0.22% of 2,4-diphenyl-4-methyl-1-pentene and 0.2% of toluene were added through a nozzle, and the nozzle rotation speed was 60r / min; the length of the reaction zone in the first tube-by-tube reaction unit was 10m, the retention time of the material in the first tube-by-tube reaction unit was 20min, the reaction temperature was 142°C, and after passing through the reaction zone, the conversion rate of methyl methacrylate was 62%; At the second mixing unit, 120ppm of diisopropylbenzene peroxide, 0.07% of phenethyl dithiobenzoate and 0.2% of toluene were added through a nozzle, and the nozzle rotation speed was 35r / min; the length of the reaction zone in the second tube-by-tube reaction unit was 8m, the retention time of the material in the second tube-by-tube reaction unit was 18min, the reaction temperature was 162°C, and after passing through the reaction zone, the conversion rate of methyl methacrylate was 67%; At the third mixed flow unit, 60 ppm of azobisisoheptanenitrile, 0.005% of phenethyl dithiobenzoate and 0.2% of toluene were added through a nozzle, and the nozzle rotation speed was 30 r / min; the length of the reaction zone in the third tubular reaction unit was 7 m, the retention time of the material in the third tubular reaction unit was 15 min, the reaction temperature was 182° C. After passing through the reaction zone, the conversion rate of methyl methacrylate was 73%, and a slurry material was obtained; (3) The slurry material discharged from the segmented tubular reactor is passed into the deashing extruder for deashing at a temperature of 260°C and an absolute pressure of 25KPa. The unreacted monomers, solvents, oligomers and trace amounts of chain transfer agents in the material are gasified and separated from the polymer compound. The gas enters the monomer recovery device. The polymer material can be extruded through the extruder and granulated to obtain PMMA particles, etc. The material stays in the deashing extruder for 30 minutes.

[0039] According to the standard ISO13468, the optical properties of PMMA particles are tested, and it can be known that the total light transmittance coefficient of the PMMA particles is greater than 92%.

[0040] Example 9 This embodiment provides an optical grade PMMA production process, which is as follows: (1) Based on the total weight of the raw material monomers and the solvent as 100%, 97% by weight of alkyl methacrylate, 2% by weight of butyl acrylate and 1% by weight of isobornyl acrylate were mixed evenly in a mixing buffer tank, and then high-purity N 2 The mixture was replaced until the oxygen content was ≤1ppm; then, 2% methyl acetate, 200ppm di-tert-butyl peroxide and 0.1% benzyl dithiobenzoate were mixed evenly in a pipeline mixer, and then added into a fully mixed reactor with a stirring device and made of 316L. The wall of the fully mixed reactor was polished and super-bright, and a heat transfer oil heating system and a cooling heat transfer system were used; the stirring speed was controlled to be 50r / min, the bubble point temperature of the heat transfer material in the temperature control coil in the fully mixed reactor was 138°C, the reaction temperature was 138°C, the reaction residence time was 180min, the pressure was controlled at 1.5MPa, and a prepolymerization reaction was carried out, and the conversion rate of alkyl methacrylate was 47%; (2) The prepolymerization reaction system discharged from the fully mixed reactor is introduced into three independent segmented tubular reactors (made of 316L stainless steel), wherein the three independent segmented tubular reactors include a first mixing unit, a first tubular reaction unit, a second mixing unit, a second tubular reaction unit, a third mixing unit and a third tubular reaction unit arranged from bottom to top. The inner diameter of the segmented tubular reactor is 0.5 m, the number is 2, and the pressure in the entire shell is 2.7 MPa; At the first mixed flow unit, 120ppm of diisopropyl peroxydicarbonate, 0.18% of benzyl dithiobenzoate and 0.15% of methyl acetate were added through a nozzle, and the nozzle rotation speed was 50r / min; the length of the reaction zone in the first tube-by-tube reaction unit was 24m, the retention time of the material in the first tube-by-tube reaction unit was 40min, the reaction temperature was 158°C, and after passing through the reaction zone, the conversion rate of alkyl methacrylate was 54%; At the second mixed flow unit, 150 ppm of diisopropyl peroxydicarbonate, 0.12% of 2,4-diphenyl-4-methyl-1-pentene and 0.15% of methyl acetate were added through a nozzle, and the nozzle rotation speed was 50r / min; the length of the reaction zone in the second tube-by-tube reaction unit was 12m, the retention time of the material in the second tube-by-tube reaction unit was 20min, the reaction temperature was 170°C, and after passing through the reaction zone, the conversion rate of alkyl methacrylate was 62%; At the third mixed flow unit, 80 ppm of azobisisobutyronitrile, 0.02% of 2,4-diphenyl-4-methyl-1-pentene and 0.15% of methyl acetate were added through a nozzle, and the nozzle rotation speed was 50 r / min; the length of the reaction zone in the third tubular reaction unit was 6 m, the retention time of the material in the third tubular reaction unit was 10 min, the reaction temperature was 182° C. After passing through the reaction zone, the conversion rate of alkyl methacrylate was 67%, and a slurry material was obtained; (3) The slurry material discharged from the segmented tubular reactor is passed into the deashing extruder for deashing at a temperature of 240°C and an absolute pressure of 10KPa. The unreacted monomers, solvents, oligomers and trace amounts of chain transfer agents in the material are gasified and separated from the polymer compound. The gas enters the monomer recovery device. The polymer material can be extruded through the extruder and granulated to obtain PMMA particles, etc. The material stays in the deashing extruder for 35 minutes.

[0041] According to the standard ISO13468, the optical properties of PMMA particles are tested, and it can be known that the total light transmittance coefficient of the PMMA particles is greater than 92%.

[0042] Example 10 This embodiment provides an optical grade PMMA production process, which is as follows: (1) Based on the total weight of the raw monomers and the solvent as 100%, 95% by weight of methyl methacrylate, 3% by weight of methyl acrylate and 2% by weight of cyclohexyl methacrylate were mixed uniformly in a mixing buffer tank, and then high-purity Ar was introduced for displacement until the oxygen content was ≤1ppm; then, 4% of toluene, 90ppm of azobisisoheptanenitrile and 0.25% of benzyl dithiobenzoate were mixed uniformly in a pipeline mixer, and then added into a fully mixed reactor with a stirring device and made of Q235B material, the wall surface of the fully mixed reactor was polished super-bright surface, and a heat transfer oil heating system and a cooling heat transfer system were used; the stirring speed was controlled to be 60r / min, the bubble point temperature of the heat transfer material in the temperature control coil in the fully mixed reactor was 145°C, the reaction temperature was 140°C, the reaction residence time was 150min, the pressure was controlled at 1.0MPa, and a prepolymerization reaction was carried out, and the methyl methacrylate conversion rate was 43%; (2) The prepolymerization reaction system discharged from the fully mixed reactor is introduced into three independent segmented tubular reactors (made of Q235B stainless steel). The three independent segmented tubular reactors include a first mixing unit, a first tubular reaction unit, a second mixing unit, a second tubular reaction unit, a third mixing unit and a third tubular reaction unit arranged from bottom to top. The inner diameter of the segmented tubular reactor is 0.3 m, the number is 5, and the pressure in the entire shell is 2.2 MPa; At the first mixed flow unit, 100ppm of diisopropyl peroxydicarbonate, 0.12% of 2,4-diphenyl-4-methyl-1-pentene and 0.2% of toluene were added through a nozzle, and the nozzle rotation speed was 60r / min; the length of the reaction zone in the first tube-by-tube reaction unit was 12m, the retention time of the material in the first tube-by-tube reaction unit was 35min, the reaction temperature was 155°C, and after passing through the reaction zone, the conversion rate of methyl methacrylate was 54%; At the second mixing unit, 50 ppm of dodecyl peroxide, 0.08% of 2-dithiobenzoic acid cumyl ester and 0.2% of toluene were added through a nozzle, and the nozzle rotation speed was 60r / min; the length of the reaction zone in the second tube-by-tube reaction unit was 10m, the retention time of the material in the second tube-by-tube reaction unit was 30min, the reaction temperature was 175°C, and after passing through the reaction zone, the conversion rate of methyl methacrylate was 63%; At the third mixed flow unit, 50 ppm of azobisisobutyronitrile, 0.05% of isopropyl dithiobenzoate and 0.2% of toluene were added through a nozzle, and the nozzle rotation speed was 60 r / min; the length of the reaction zone in the third tubular reaction unit was 5 m, the retention time of the material in the third tubular reaction unit was 15 min, the reaction temperature was 195° C. After passing through the reaction zone, the conversion rate of methyl methacrylate was 72%, and a slurry material was obtained; (3) The slurry material discharged from the segmented tubular reactor is passed into the deashing extruder for deashing at a temperature of 230°C and an absolute pressure of 10KPa. The unreacted monomers, solvents, oligomers and trace amounts of chain transfer agents in the material are gasified and separated from the polymer compound. The gas enters the monomer recovery device. The polymer material can be extruded through the extruder and granulated to obtain PMMA particles, etc. The material stays in the deashing extruder for 40 minutes.

[0043] According to the standard ISO13468, the optical properties of PMMA particles are tested, and it can be known that the total light transmittance coefficient of the PMMA particles is greater than 92%.

[0044] Embodiment 11 This embodiment provides an optical grade PMMA production process, which is as follows: (1) Based on the total weight of the raw monomers and the solvent as 100%, 85% by weight of methyl methacrylate, 10% by weight of methyl acrylate and 5% by weight of cyclohexyl methacrylate were mixed uniformly in a mixing buffer tank, and then high-purity Ar was introduced for displacement until the oxygen content was ≤1ppm; then, 3% of methanol, 120ppm of azobisisobutyronitrile and 0.15% of phenethyl dithiobenzoate were mixed uniformly in a pipeline mixer, and then added into a fully mixed reactor with a stirring device and made of 304SS. The wall surface of the fully mixed reactor was polished and super-bright, and a heat transfer oil heating system and a cooling heat transfer system were used; the stirring speed was controlled to be 50r / min, the bubble point temperature of the heat transfer material in the temperature control coil in the fully mixed reactor was 140°C, the reaction temperature was 130°C, the reaction residence time was 180min, the pressure was controlled at 1.5MPa, and a prepolymerization reaction was carried out, and the conversion rate of methyl methacrylate was 38%; (2) The prepolymerization reaction system discharged from the fully mixed reactor is introduced into three independent segmented tubular reactors (made of Q345R stainless steel). The three independent segmented tubular reactors include a first mixing unit, a first tubular reaction unit, a second mixing unit, a second tubular reaction unit, a third mixing unit and a third tubular reaction unit arranged from bottom to top. The inner diameter of the segmented tubular reactor is 0.4 m, the number is 3, and the pressure in the entire shell is 3.0 MPa; At the first mixed flow unit, 70 ppm of dibenzoyl peroxide, 0.18% of 2,4-diphenyl-4-methyl-1-pentene and 0.1% of methanol were added through a nozzle, and the nozzle rotation speed was 45r / min; the length of the reaction zone in the first tube-by-tube reaction unit was 20m, the retention time of the material in the first tube-by-tube reaction unit was 40min, the reaction temperature was 150°C, and after passing through the reaction zone, the conversion rate of methyl methacrylate was 57%; At the second mixed flow unit, 150 ppm of dodecyl peroxide, 0.03% of phenethyl dithiobenzoate and 0.1% of methanol were added through a nozzle, and the nozzle rotation speed was 45 r / min; the length of the reaction zone in the second tube-by-tube reaction unit was 7 m, the retention time of the material in the second tube-by-tube reaction unit was 15 min, the reaction temperature was 170 ° C, and after passing through the reaction zone, the conversion rate of methyl methacrylate was 63%; At the third mixed flow unit, 60 ppm of azobisisoheptanenitrile, 0.01% of phenethyl dithiobenzoate and 0.1% of methanol were added through a nozzle, and the nozzle rotation speed was 45 r / min; the length of the reaction zone in the third tubular reaction unit was 6 m, the retention time of the material in the third tubular reaction unit was 12 min, the reaction temperature was 190 ° C, and after passing through the reaction zone, the conversion rate of methyl methacrylate was 70%, and a slurry material was obtained; (3) The slurry material discharged from the segmented tubular reactor is passed into the deashing extruder for deashing at a temperature of 280°C and an absolute pressure of 30KPa. The unreacted monomers, solvents, oligomers and trace amounts of chain transfer agents in the material are gasified and separated from the polymer compound. The gas enters the monomer recovery device. The polymer material can be extruded through the extruder and granulated to obtain PMMA particles, etc. The material stays in the deashing extruder for 20 minutes.

[0045] According to the standard ISO13468, the optical properties of PMMA particles are tested, and it can be known that the total light transmittance coefficient of the PMMA particles is greater than 92%. Comparative Example 1 Based on Example 7, the difference between this comparative example and Example 7 is: Instead of using a segmented tubular reactor, three reactors are used in series, and a high-viscosity feed pump is added between adjacent reactors, and an independent heat transfer oil system is used. The rest is the same as in Example 7.

[0046] Finally, the conversion rate of methyl methacrylate was 72%, and the obtained PMMA particles were tested (ISO13468), and the total light transmittance was > 92%. In addition, according to simulation calculations, it can be seen that: for every ton of PMMA product produced, the power consumption increases by 9%. That is, compared with Example 7, although the conversion rate of methyl methacrylate in both is similar, and both can obtain optical grade PMMA products, the production energy consumption in Comparative Example 1 is significantly increased, which is not conducive to the cost control of industrial production.

[0047] Comparative Example 2 On the basis of Example 8, the difference between this comparative example and Example 8 is: At the first mixing unit, 400 ppm of dicumyl peroxide (initiator) and 0.295% of phenylethyl dithiobenzoate (chain transfer agent) were added; at the second mixing unit and the third mixing unit, no auxiliary agent was added. The rest was the same as in Example 8.

[0048] Finally, the conversion rate of methyl methacrylate was 69%, and the PMMA particles obtained were tested (ISO13468), and their total light transmittance was <92%. In addition, according to simulation calculations, it can be seen that for every ton of PMMA product produced, the steam consumption increases by 20%. That is, compared with Example 8, the conversion rate of methyl methacrylate in this comparative example is significantly reduced, and high-quality optical-grade products cannot be obtained, and the production energy consumption is significantly increased.

[0049] Comparative Example 3 Based on Example 9, the difference between this comparative example and Example 9 is: The first mixing unit, the second mixing unit and the third mixing unit in the fully mixed reactor and the segmented tubular reactor use the same auxiliary agent, that is, di-tert-butyl peroxide and benzyl dithiobenzoate. The rest is the same as in Example 9.

[0050] Finally, the obtained PMMA particles were tested (ISO13468), and the total light transmittance was less than 92%. That is, compared with Example 9, this comparative example cannot obtain high-quality optical-grade products.

[0051] Comparative Example 4 Based on Example 10, the difference between this comparative example and Example 10 is: No cyclohexyl methacrylate was added, that is, the weight proportion of the added methyl methacrylate was 95%, and the weight proportion of the methyl acrylate was 5%. The rest was the same as in Example 10.

[0052] Finally, the obtained PMMA particles were tested (ISO13468), and the total light transmittance was >92%. In addition, the ISO1133 test method was used: under the test conditions of 230°C / 3.8kg, the melt index of the PMMA particles in Example 10 was 16 (g / 10min), and the melt index of the PMMA particles in this comparative example was 9 (g / 10min); and, using the ISO179 test method, the simply supported beam unnotched impact strength (1eU) of the PMMA particles in Example 10 was 20 kJ / m², and the simply supported beam unnotched impact strength (1eU) of the PMMA particles in this comparative example was 17 kJ / m². Furthermore, it can be seen that compared with Example 10, this comparative example cannot obtain high-quality optical-grade products, and the fluidity and toughness of the PMMA particles are significantly reduced.

[0053] Comparative Example 5 Based on Example 11, the difference between this comparative example and Example 11 is: The residence time of the material system in the first tube array reaction unit, the second tube array reaction unit and the third tube array reaction unit are 16 min\6 min\5 min (u*1s>0.025*D) respectively, and the rest are the same as in Example 11.

[0054] Finally, the obtained PMMA particles were tested (ISO13468), and the total light transmittance was <92%. In addition, using the ISO527 test method, the tensile strength of the PMMA particles in Example 11 was 70 (MPa), and that of the PMMA particles in this comparative example was 55 (MPa); using the ISO179 test method, the simply supported beam unnotched impact strength (1eU) of the PMMA particles in Example 11 was 20 kJ / m², and that of the PMMA particles in the comparative example was 17 kJ / m². Furthermore, it can be seen that compared with Example 11, this comparative example cannot obtain high-quality optical-grade products, and the strength of the PMMA particles is significantly reduced.

[0055] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any simple modification or equivalent change made to the above embodiment based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A production process for continuously preparing methacrylic acid polymers, characterized in that: The steps include: S1 batching: adding raw materials of alkyl methacrylate monomer, alkyl acrylate monomer and (meth) acrylate cyclic ester monomer into a mixing buffer tank until the total volume of the raw materials accounts for 2 / 3 to 4 / 5 of the volume of the mixing buffer tank, then stopping the addition; mixing the raw materials evenly to obtain a mixture; then, introducing protective gas into the mixing buffer tank to replace the gas in the mixing buffer tank; Among them, the mixing buffer tank is controlled such that: the oxygen content in each monomer raw material is ≤1ppm; the pressure is 20-50KPa, and the temperature is 20-50℃; S2 prepolymerization: adding the solvent, the auxiliary agent and the gas-substituted mixture obtained in step S1 into a fully mixed reactor, heating the fully mixed reactor to 90-140°C at a rate of 1-3°C / min; then, staying for 30-240 min to obtain a prepolymerization reaction system; Among them, the fully mixed reactor is controlled: the difference between the actual maximum temperature of the prepolymerization reaction and the set temperature is not higher than 10°C, the pressure is 0.5-2.0MPa, the oxygen content is ≤2ppm, and the conversion rate of the alkyl methacrylate monomer is 30-50%; S3 polymerization: the prepolymerization reaction system obtained in step S2 is introduced into a segmented shell-and-tube reactor, and the polymerization temperature in the segmented shell-and-tube reactor is controlled to be 140-200° C., the pressure is 1.5-3.5 MPa, and the moving speed of the material in the shell-and-tube reactor is 0.001-0.1 m / s, and finally, a slurry product is obtained; S4 deashing and separation: the slurry product obtained in step S3 is introduced into a deashing and extruding integrated machine for deashing and separation to obtain a polymer material and waste materials including unreacted monomers, solvents, oligomers and additives.

2. The process for continuously preparing methacrylic acid polymers according to claim 1, characterized in that: In step S1, based on the sum of the weight of the monomer raw materials being 100%, the content of the alkyl methacrylate monomer is 68-95%, the content of the alkyl acrylate monomer is 3-30%, and the content of the (meth)acrylate cyclic ester monomer is 2-15%.

3. The process for continuously preparing methacrylic acid polymers according to claim 2, characterized in that: In step S2, the amount of solvent added is 1-10% of the total amount of the monomer raw material, and the amount of auxiliary agent added is 0.05-0.3% of the total amount of the monomer raw material.

4. The process for continuously preparing methacrylic acid polymers according to claim 3, characterized in that: In step S3, the amount of the auxiliary agent added again is 0.04-0.55%.

5. The process for continuously preparing methacrylic acid polymers according to claim 4, characterized in that: In step S3, the segmented shell-and-tube reactor includes a first reaction zone, a second reaction zone and a third reaction zone which are sequentially distributed from bottom to top, and the temperature relationship in the three reaction zones is: 7°C ≤ temperature of the second reaction zone - temperature of the first reaction zone = temperature of the third reaction zone - temperature of the second reaction zone ≤ 20°C.

6. The process for continuously preparing methacrylic acid polymers according to claim 5, characterized in that: Control the first stage reaction zone: the amount of the additive added again is 0.02-0.2% of the total amount of the monomer raw material, the material stays for 20-100 minutes, the temperature is 140-155°C, and the total conversion rate of the alkyl methacrylate monomer is accumulated to 40-55%; Control the second stage reaction zone: the amount of the additive added again is 0.01-0.2% of the total amount of the monomer raw material, the material stays for 10-80 minutes, the temperature is 155-175°C, and the total conversion rate of the alkyl methacrylate monomer is accumulated to 50-65%; Control the third reaction zone: the amount of the additive added again is 0.01-0.15% of the total amount of the monomer raw material, the material stays for 5-60 minutes, the temperature is 175-200°C, and the total conversion rate of the alkyl methacrylate monomer is accumulated to 60-75%.

7. The process for continuously preparing methacrylic acid polymers according to claim 1, characterized in that: In step S4, deashing and separation is performed at a temperature of 200 to 280° C. and an absolute pressure of 10 to 40 KPa for 10 to 30 minutes.

8. The process for continuously preparing methacrylic acid polymers according to claim 7, characterized in that: In step S4, the waste materials including unreacted monomers, solvents, oligomers and additives are introduced into a monomer recovery device, and after separation, the recovered unreacted monomers are recycled to the batching process.

9. A production system for continuously preparing methacrylic acid polymers, characterized in that: A production system adopted by the production process described in any one of claims 1 to 8, the production system comprising a mixing buffer tank (1), a fully mixed reactor (2), a segmented tubular reactor (3) and a deashing and extruding integrated machine (4); The mixing buffer tank (1) is connected to an alkyl methacrylate monomer metering tank (101) via an alkyl methacrylate monomer feed pipe (100), is further connected to an alkyl acrylate monomer metering tank (103) via an alkyl acrylate monomer feed pipe (102), is further connected to a (meth)acrylate cyclic ester monomer metering tank (105) via a (meth)acrylate cyclic ester monomer feed pipe (104), and is further connected to a protective gas storage tank (5) via a protective gas inlet pipe I (106); the upper displacement gas outlet of the mixing buffer tank (1) is connected to a displacement gas outlet pipe (107); and the upper material outlet of the mixing buffer tank (1) is connected to a fully mixed reactor (2) via a mixed material delivery pipe (108); The fully mixed reactor (2) is arranged at the rear side of the station of the mixing buffer tank (1); the fully mixed reactor (2) is connected to a solvent metering tank (201) via a solvent feed pipe (200), is further connected to an auxiliary agent metering tank (203) via an auxiliary agent feed pipe I (202), and is further connected to a protective gas storage tank (5) via a protective gas feed pipe II (204); an upper discharge port of the fully mixed reactor (2) is connected to a segmented tubular reactor (3) via a prepolymerization reaction system delivery pipe (209); The segmented shell-and-tube reactor (3) is arranged at the rear side of the workstation of the fully mixed reactor (2), and comprises a shell (300) and at least two mixing units (301) and at least two shell-and-tube reaction units (302) arranged in the shell (300), wherein the mixing units (301) and the shell-and-tube reaction units (302) are arranged at intervals and are sequentially distributed upwards; a feed port is provided on the bottom mixing unit (301), and a discharge port is provided on the top shell-and-tube reaction unit (302); a continuous passage for polymerization reaction is formed between the feed port, the mixing unit (301), the shell-and-tube reaction unit (302) and the discharge port; and the upper discharge port of the segmented shell-and-tube reactor (3) is connected to the deashing and extruding integrated machine (4) via a reactant conveying pipe (310); The deashing and extruding integrated machine (4) is arranged at the rear side of the workstation of the segmented tubular reactor (3); the polymer outlet on the deashing and extruding integrated machine (4) is connected to the methacrylic acid polymer storage tank (6); the waste material outlet on the deashing and extruding integrated machine (4) is connected to the monomer recovery device (7); and the monomer outlet on the monomer recovery device (7) is connected to the mixing buffer tank (1) via a recycling pipe (700); A continuous passage for producing methacrylic acid series polymer is formed between the mixing buffer tank (1), the fully mixed reactor (2), the segmented tubular reactor (3), the deashing and extruding integrated machine (4) and the methacrylic acid series polymer storage tank (6).

10. The production system for continuously preparing methacrylic acid polymers according to claim 9, characterized in that: The fully mixed reactor (2) is provided with a stirring device, and a temperature control coil (206) is sleeved on the stirring device; one end of the temperature control coil (206) is connected to a heat transfer material inlet pipe (207), and the other end is connected to a heat transfer material outlet pipe (208); A three-paddle stirring mechanism (205) is provided at the bottom of the stirring device. The three-paddle stirring mechanism (205) comprises a blade assembly I, a blade assembly II and a blade assembly III which are sequentially arranged from bottom to top. The blades in the blade assembly I are twisted clockwise by 35 to 45°, the blades in the blade assembly II are twisted counterclockwise by 35 to 45°, and the blades in the blade assembly III are twisted clockwise by 35 to 45°. A heating jacket (210) is provided on the outer side of the fully mixed reactor (2); the heat source in the heating jacket (210) is heat transfer oil; the inlet of the heating jacket (210) is connected to a heat transfer oil inlet pipe I (211); and the outlet of the heating jacket (210) is connected to a heat transfer oil outlet pipe I (212).

11. The production system for continuously preparing methacrylic acid polymers according to claim 10, characterized in that: The heat transfer material in the temperature control coil (206) is a liquid feed, the vaporization temperature of the heat transfer material under normal pressure is 5 to 10° C. higher than the set reaction temperature in the fully mixed reactor (2), and the feed temperature of the heat transfer material is 5 to 10° C. lower than the set reaction temperature.

12. The production system for continuously preparing methacrylic acid-based polymers according to claim 9, characterized in that: Each of the flow mixing units (301) is connected to an auxiliary agent feeding pipe II (306), and the flow mixing unit (301) comprises a flow mixing cavity (303) in communication with the auxiliary agent feeding pipe II (306); The tube-in-tube reaction unit (302) at the bottom is connected to a heat transfer oil inlet pipe II (307), the tube-in-tube reaction unit (302) at the top is connected to a heat transfer oil outlet pipe II (308), and the upper-level tube-in-tube reaction unit (302) and the lower-level tube-in-tube reaction unit (302) are connected via a heat transfer oil connecting pipe (309). The tube-in-tube reaction unit (302) comprises tubes (304) arranged in a longitudinal direction, and a temperature control cavity (305) between the tubes (304) and the shell (300) is used to accommodate heat transfer oil, and the temperature control cavity (305) is connected to a cold oil feed pipe (311).

13. A control system capable of continuously preparing methacrylic acid polymers, characterized in that: In the production system according to any one of claims 9 to 12, the control system comprises a DCS controller (8), the DCS controller (8) is connected to a human-machine interface via a data input interface, the DCS controller (8) is connected to a data acquisition unit via a data feedback interface, and the DCS controller (8) is connected to an execution unit via a data output interface; The DCS controller (8) comprises a batching control module (81), a pre-polymerization control module (82) and a polymerization control module (83); The data acquisition unit is arranged in the production system of the methacrylic acid series polymer, and the data acquisition unit comprises a sensor group for data acquisition and transmission in the production process of the methacrylic acid series polymer; The execution unit is arranged in a production system of methacrylic acid polymers, and includes a group of equipment for preparing and regulating methacrylic acid polymers.

14. The control system for continuously preparing methacrylic acid polymers according to claim 13, characterized in that: The sensor group comprises an alkyl methacrylate monomer metering pump (10) provided on an alkyl methacrylate monomer feed pipe (100), an alkyl acrylate monomer metering pump (12) provided on an alkyl acrylate monomer feed pipe (102), a (meth)acrylate cyclic ester monomer metering pump (14) provided on a (meth)acrylate cyclic ester monomer feed pipe (104), an oxygen content analyzer (16) provided on a displacement gas outlet pipe (107), and a solvent meter (17) provided on a solvent feed pipe (200). The metering pump (22), an auxiliary agent metering pump I (24) provided on the auxiliary agent feeding pipe I (202), an auxiliary agent metering pump II (34) provided on the auxiliary agent feeding pipe II (306), an alkyl methacrylate monomer metering pump (10), an alkyl acrylate monomer metering pump (12), a (meth)acrylic acid cyclic ester monomer metering pump (14), an oxygen content analyzer (16), a solvent metering pump (22), an auxiliary agent metering pump I (24), and an auxiliary agent metering pump II (34) are all connected to a batching control module (81); The sensor group further comprises a pressure sensor I (17) and a temperature sensor I (18) provided on the mixing buffer tank (1), and a pressure sensor II (28) and a temperature sensor II (29) provided on the fully mixed reactor (2); the pressure sensor I (17), the temperature sensor I (18), the pressure sensor II (28) and the temperature sensor II (29) are all connected to a prepolymerization control module (82); the prepolymerization control module (82) is connected to a solvent metering pump (22) and an auxiliary agent metering pump I (24); The sensor group further comprises a pressure sensor III (39) and a temperature sensor III (40) provided on the mixing flow unit (301), and a pressure sensor IV (41) and a temperature sensor IV (42) provided on the tube-in-tube reaction unit (302); the pressure sensor III (39), the temperature sensor III (40), the pressure sensor IV (41) and the temperature sensor IV (42) are all connected to the polymerization control module (83); the polymerization control module (83) is connected to the auxiliary agent metering pump II (34).

15. The control system for continuously preparing methacrylic acid polymers according to claim 14, characterized in that: The equipment group comprises an alkyl methacrylate monomer feed control valve (9) provided on an alkyl methacrylate monomer feed pipe (100), an alkyl acrylate monomer feed control valve (11) provided on an alkyl acrylate monomer feed pipe (102), a (meth)acrylate cyclic ester monomer feed control valve (13) provided on a (meth)acrylate cyclic ester monomer feed pipe (104), a protective gas feed control valve I (15) provided on a protective gas feed pipe I (106), and a solvent feed control valve (200) provided on a solvent feed pipe (201). 0), an auxiliary agent feed control valve I (23) provided on the auxiliary agent feed pipe I (202) and an auxiliary agent feed control valve II (33) provided on the auxiliary agent feed pipe II (306), an alkyl methacrylate monomer feed control valve (9), an alkyl acrylate monomer feed control valve (11), a (meth)acrylate cyclic ester monomer feed control valve (13), a protective gas feed control valve I (15), a solvent feed control valve (20), an auxiliary agent feed control valve I (23) and an auxiliary agent feed control valve II (33) are all connected to a batching control module (81); The equipment group further comprises a protective gas feed control valve II (25) arranged on the protective gas inlet pipe II, a heat transfer material feed control valve (26) arranged on the heat transfer material inlet pipe (207), a heat transfer material discharge control valve (27) arranged on the heat transfer material discharge pipe (208), a heat transfer oil feed control valve I (31) arranged on the heat transfer oil inlet pipe I (211), and a heat transfer oil discharge control valve I (32) arranged on the heat transfer oil outlet pipe I (212); the protective gas feed control valve II (25), the heat transfer material feed control valve (26), the heat transfer material discharge control valve (27), the heat transfer oil feed control valve I (31), and the heat transfer oil discharge control valve I (32) are all connected to the prepolymerization control module (82); the prepolymerization control module (82) is connected to the solvent feed control valve (20) and the auxiliary agent feed control valve I (23); The equipment group further includes a heat transfer oil feed control valve II (35) provided on the heat transfer oil inlet pipe II (307), a heat transfer oil discharge control valve II (36) provided on the heat transfer oil outlet pipe II (308), and a cold oil feed control valve (37) provided on the cold oil feed pipe (311); the heat transfer oil feed control valve II (35), the heat transfer oil discharge control valve II (36), and the cold oil feed control valve (37) are all connected to the polymerization control module (83); the polymerization control module (83) is connected to the auxiliary agent feed control valve II (33); The alkyl methacrylate monomer metering pump (10) and the alkyl methacrylate monomer feed control valve (9) are interlocked by electrical signals, and a control loop is formed by electrical signals between the alkyl methacrylate monomer metering pump (10), the batching control module (81) and the alkyl methacrylate monomer feed control valve (9); The alkyl acrylate monomer metering pump (12) and the alkyl acrylate monomer feed control valve (11) are interlocked by electrical signals, and a control loop is formed by electrical signals between the alkyl acrylate monomer metering pump (12), the batching control module (81) and the alkyl acrylate monomer feed control valve (11); The (meth)acrylate cyclic ester monomer metering pump (14) and the (meth)acrylate cyclic ester monomer feed control valve (13) are interlocked by electrical signals, and a control loop is formed by electrical signals between the (meth)acrylate cyclic ester monomer metering pump (14), the batching control module (81) and the (meth)acrylate cyclic ester monomer feed control valve (13); The solvent metering pump (22) and the solvent feed control valve (20) are interlocked by electrical signals, and a control loop is formed between the solvent metering pump (22), the batching control module (81), the prepolymerization control module (82) and the solvent feed control valve (20); The additive metering pump I (24) and the additive feed control valve I (23) are interlocked by electrical signals, and a control loop is formed by electrical signals between the additive metering pump I (24), the batching control module (81), the prepolymerization control module (82) and the additive feed control valve I (23); The auxiliary agent metering pump II (34) and the auxiliary agent feed control valve II (33) are interlocked by electrical signals, and a control loop is formed by electrical signals between the auxiliary agent metering pump II (34), the batching control module (81), the polymerization control module (83) and the auxiliary agent feed control valve II (33); The temperature sensor I (18), the temperature sensor II (29), the heat transfer material feed control valve (26), the heat transfer material discharge control valve (27), the heat transfer oil feed control valve I (31) and the heat transfer oil discharge control valve I (32) are interlocked by electrical signals, and the temperature sensor I (18), the temperature sensor II (29), the prepolymerization control module (82), the heat transfer material feed control valve (26), the heat transfer material discharge control valve (27), the heat transfer oil feed control valve I (31) and the heat transfer oil discharge control valve I (32) form a control loop by electrical signals; The temperature sensor III (40), the temperature sensor IV (42), the heat transfer oil feed control valve II (35), the heat transfer oil discharge control valve II (36) and the cold oil feed control valve (37) are interlocked by electrical signals, and a control loop is formed by electrical signals between the temperature sensor III (40), the temperature sensor IV (42), the polymerization control module (83), the heat transfer oil feed control valve II (35), the heat transfer oil discharge control valve II (36) and the cold oil feed control valve (37).

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