High-efficiency flame-retardant polymer additive synthesis reaction device and method thereof

Abstract

This invention relates to the field of polymer material synthesis and chemical reaction equipment, specifically to a high-efficiency flame-retardant polymer additive synthesis reaction device and method; it includes a main reaction pipeline, a feeding mechanism, an ultrasonic intervention mechanism, a self-smoothing diffusion mechanism, and a controller; the system transports materials through a servo motor and an external gear pump, and achieves stable diffusion in the pipeline through the linkage of a flexible bellows, a damping chamber, and a pressure relief valve; its core is to use a piezoelectric ceramic transducer to emit high-frequency ultrasonic waves, generating vibration and micro-cavitation effects in the boundary layer, destroying the physical entanglement of materials and inducing near-wall plug flow slippage; this invention completely eliminates the pipe wall retention and core flow of high-viscosity fluids without increasing mechanical shear force, avoids macromolecular chain breakage or thermal degradation, resolves the contradiction between mass and heat transfer deterioration and shear sensitivity, and greatly improves the uniformity of the residence time of materials in continuous polymerization reactions.

Description

Technical Field

[0001] This invention relates to the field of polymer material synthesis and chemical reaction equipment, specifically to a high-efficiency flame-retardant polymer additive synthesis reaction apparatus and method. Background Technology

[0002] Under the current operating conditions of continuous synthesis processes for flame-retardant polymer additives, the reactants inevitably undergo complex phase transitions and rheological processes during polymerization, exhibiting significant high-viscosity non-Newtonian fluid characteristics. When continuous polymerization occurs within tubular channels, these materials are extremely sensitive to mechanical shear forces and are prone to deterioration in mass and heat transfer. To continuously synthesize these high-viscosity non-Newtonian reactive fluids, existing methods generally employ traditional tubular channel structures, relying solely on increasing pump pressure or applying mechanical stirring to propel the fluid and promote mixing. While this approach is suitable for conventional low-viscosity polymerization... While it possesses a certain continuous processing capability in synthetic applications, high-viscosity fluids easily form extremely thick retention layers on the pipe walls, leading to severe thermal degradation. Simultaneously, the central fluid often forms core crossflows, causing unreacted fluids to be discharged prematurely. Simply increasing mechanical thrust or stirring not only fails to effectively eliminate these flow field defects but also further exacerbates the core crossflow phenomenon or directly breaks down macromolecular chains. This creates a core contradiction between the deterioration of mass and heat transfer within the flow channel and the shear sensitivity of the material, resulting in an extremely uneven distribution of the residence time of the reactants. This makes it difficult to support the process requirements for highly consistent molecular weight of flame retardants such as ammonium polyphosphate.

[0003] Therefore, how to effectively eliminate the stagnant layer on the pipe wall and the core flow phenomenon without increasing the overall mechanical shear force, thereby improving the material uniformity of the continuous polymerization reaction of polymer additives and the stability of the synthesis equipment operation, has become an urgent technical problem to be solved. Summary of the Invention

[0004] To solve the above-mentioned technical problems, the present invention provides a highly efficient flame-retardant polymer additive synthesis reaction apparatus and method. Specifically, the technical solution of the present invention is as follows: A high-efficiency flame-retardant polymer additive synthesis reaction apparatus, comprising: The reaction main pipeline, feeding mechanism, ultrasonic intervention mechanism, self-suppressing diffusion mechanism, and controller are included. The reaction main pipeline is a hollow cylindrical straight pipe that serves as the foundation for the flow of reactants. The feeding mechanism is located at the feed end of the reaction main pipeline and includes a servo motor and an external gear pump. The output shaft of the servo motor is connected to the drive gear shaft of the external gear pump, and the discharge port of the external gear pump is connected to the reaction main pipeline. The self-suppressing diffuser is connected in series in the middle section of the main reaction pipeline. It includes a hollow diffuser shell that is large in the middle and small at both ends, a flexible bellows, and a mechanical pressure relief valve. The flexible bellows is coaxially inserted into the diffuser shell and sealed at both ends. A closed annular damping chamber is formed between the outer wall of the flexible bellows and the inner wall of the diffuser shell. The mechanical pressure relief valve is installed in the diffuser shell and connected to the chamber. Its valve core is connected to the outer wall of the flexible bellows through a connecting rod. The ultrasonic intervention mechanism includes a piezoelectric ceramic transducer, which is fixed to the outer wall of the main reaction pipeline along the axial and circumferential directions to emit high-frequency ultrasonic waves into the pipeline; the controller controls the servo motor and the piezoelectric ceramic transducer.

[0005] Furthermore, the output shaft of the servo motor is directly connected to the drive gear shaft of the external gear pump via a plum blossom-shaped flexible coupling, and the discharge port of the external gear pump is fixedly connected to the feed end of the main reaction pipeline via a flange and bolts.

[0006] Furthermore, the piezoelectric ceramic transducer is configured to generate high-frequency vibrations and microcavitation effects within the boundary layer of the inner wall of the main reaction pipe, thereby disrupting the physical entanglement network of the reactants and generating a near-wall plug flow slip mode.

[0007] Furthermore, the flexible corrugated pipe is made of polytetrafluoroethylene, and the internal channel of the flexible corrugated pipe is connected to the internal channel of the main reaction pipeline. The annular damping chamber is filled with compressed air, and the flexible corrugated pipe is configured to expand radially or stretch axially according to the pressure pulsation of the reactants.

[0008] Furthermore, the main reaction pipeline is made of stainless steel.

[0009] Furthermore, the diffuser shell is spindle-shaped, and its two ends are fixedly connected in series to the main reaction pipeline by welding.

[0010] A method for synthesizing a highly efficient flame-retardant polymer additive includes: S1. Control the servo motor to drive the external meshing gear pump to press the reactant into the main reaction pipeline, and control the piezoelectric ceramic transducer to emit ultrasonic waves into the main reaction pipeline; S2. The instantaneous torque current signal in the time domain acquired during the driving process of the servo motor is converted to the frequency domain using the Fast Fourier Transform algorithm, so as to extract and separate the amplitude of the higher harmonic components of the instantaneous torque current in real time. ; S3. Real-time extraction of acoustic impedance spectrum data of the piezoelectric ceramic transducer during operation; S4. Substitute the higher harmonic components and the acoustic impedance spectrum data into the acoustic-mechanical coupled rheological model to derive and calculate the ratio of the storage modulus to the loss modulus of the current reactant. S5. The real-time average degree of polymerization of the reactants is obtained by converting the ratio of the storage modulus to the loss modulus.

[0011] As another optional control method, step S5 is followed by: S601. Obtain the preset optimal reaction path curve, compare the real-time average degree of polymerization with the corresponding value on the optimal reaction path curve, and calculate the degree of polymerization deviation value. S602. If the polymerization degree deviation value shows that the real-time average polymerization degree is lower than the corresponding value, control the increase of the working duty cycle of the piezoelectric ceramic transducer, and use the acoustic flow effect after increasing the working duty cycle to enhance micro-mixing and accelerate the reaction. S603. If the polymerization degree deviation value shows that the real-time average polymerization degree is higher than the corresponding value, control the reduction of the working frequency of the piezoelectric ceramic transducer, and at the same time control the increase of the speed of the servo motor to accelerate the outflow of the reactant material from the main reaction pipeline. S604. If the absolute value of the difference between the real-time average degree of aggregation and the corresponding value is less than or equal to the preset allowable error threshold, the current control parameters remain unchanged.

[0012] As another optional control method, step S5 is followed by: S701. Obtain the preset optimal reaction path curve, compare the real-time average degree of polymerization with the corresponding value on the optimal reaction path curve, and calculate the degree of polymerization deviation value. S702. If the polymerization degree deviation value shows that the real-time average polymerization degree is higher than the corresponding value, control the reduction of the working frequency of the piezoelectric ceramic transducer, and at the same time control the increase of the speed of the servo motor to accelerate the outflow of the reactant material from the main reaction pipeline. S703. If the degree of polymerization deviation value shows that the real-time average degree of polymerization is equal to or lower than the corresponding value, the current control parameters remain unchanged.

[0013] Furthermore, the flexible bellows and annular damping air chamber in the self-suppressing diffuser mechanism constitute a pressure response system, and the step S1 is followed by: S801. When a positive pressure peak is generated inside the reactant, the flexible bellows is compressed and expands radially outward to compress the air in the annular damping chamber, causing the cross-section of the fluid channel to change in a Venturi-like manner, and increasing the local flow channel volume through radial expansion to absorb the pressure pulse energy. S802. When the viscosity of the reactant increases sharply, causing an increase in axial frictional drag, the flexible corrugated pipe is stretched axially. S803, the axial stretching action of the flexible bellows pulls the mechanical pressure relief valve slightly open through the connecting rod, reducing the stiffness of the annular damping air chamber to absorb pressure pulsation.

[0014] The present invention has the following beneficial effects: 1. This invention uses a servo motor and an external gear pump to transport reactants, and uses a piezoelectric ceramic transducer to emit high-frequency ultrasonic waves into the main reaction pipeline, generating high-frequency vibration and microcavitation effect in the boundary layer. This structure effectively destroys the physical entanglement network of reactants and generates a near-wall plug flow slip mode, improving the flow state of the material and greatly enhancing the uniformity of residence time of the continuous polymerization reactants. 2. The flexible bellows and annular damping air chamber of the present invention constitute a pressure response system. The dynamic pressure is converted into static pressure through radial expansion of the bellows, or the mechanical pressure relief valve is slightly opened through linkage during axial tension to absorb pressure pulsation. At the same time, the real-time average aggregation degree is calculated by combining high-order harmonic components and acoustic impedance spectrum data, and the parameters are dynamically adjusted according to the deviation value. This mechanism combines automatic pressure suppression and feedback control, which significantly improves the robustness of equipment operation. Attached Figure Description

[0015] The following drawings, illustrating embodiments of this application, are incorporated herein by reference and are used to understand this application. The drawings illustrate embodiments of this application and their descriptions, serving to explain the principles of this application. In the drawings,

[0016] Figure 1 This is a schematic diagram of the overall structure of the device; Figure 2 This is a schematic diagram of the self-suppressing diffuser mechanism of the device; Figure 3 This is a schematic diagram of the mechanical pressure relief valve structure of the device; Figure 4 This is a flowchart of the method of the present invention.

[0017] In the diagram: 1. Main reaction pipeline; 2. Feeding mechanism; 3. Ultrasonic intervention mechanism; 4. Self-suppressing diffuser mechanism; 5. Servo motor; 6. External gear pump; 7. Piezoelectric ceramic transducer; 8. Diffuser shell; 9. Flexible bellows; 10. Mechanical pressure relief valve; 11. Plum blossom-shaped flexible coupling; 12. Flange; 13. Bolt; 14. Annular damping chamber; 15. Connecting rod; 16. Thermocouple temperature sensor. Detailed Implementation

[0018] In the following description, numerous specific details are set forth to provide a more thorough understanding of this application. However, it will be apparent to those skilled in the art that embodiments of this application may be practiced without one or more of these details. In other instances, certain technical features well-known in the art have not been described to avoid confusion with embodiments of this application.

[0019] Example 1: like Figure 1 As shown, a high-efficiency flame-retardant polymer additive synthesis reaction apparatus includes: The reaction main pipeline 1, feeding mechanism 2, ultrasonic intervention mechanism 3, self-suppressing and diffuser mechanism 4, and controller are included. The reaction main pipeline 1 is a hollow cylindrical straight pipe that serves as the foundation for the flow of reactants. The feeding mechanism 2 is located at the feed end of the reaction main pipeline 1 and includes a servo motor 5 and an external gear pump 6. The output shaft of the servo motor 5 is connected to the drive gear shaft of the external gear pump 6, and the outlet of the external gear pump 6 is connected to the reaction main pipeline 1. like Figure 2 As shown, the self-suppressing diffuser 4 is connected in series in the middle section of the main reaction pipeline 1, including a hollow diffuser shell 8 with a large middle section and small ends, a flexible bellows 9 and a mechanical pressure relief valve 10. The flexible bellows 9 is coaxially inserted inside the diffuser shell 8 and sealed at both ends. A sealed annular damping air chamber 14 is formed between the outer wall of the flexible bellows 9 and the inner wall of the diffuser shell 8. like Figure 3 As shown, the mechanical pressure relief valve 10 is installed on the diffuser housing 8 and connected to the air chamber 14, and its valve core is connected to the outer wall of the flexible bellows 9 through the connecting rod 15. The ultrasonic intervention mechanism 3 includes a piezoelectric ceramic transducer 7, which is attached and fixed to the outer wall of the main reaction pipeline 1 along the axial and circumferential directions, and is used to emit high-frequency ultrasonic waves into the pipeline; the controller controls the servo motor 5 and the piezoelectric ceramic transducer 7. This embodiment provides a high-efficiency flame-retardant polymer additive synthesis reaction device, which aims to solve the core contradiction between the deterioration of mass and heat transfer and shear sensitivity of high-viscosity non-Newtonian fluids in continuous polymerization reactions. In traditional tubular channels, high-viscosity fluids are prone to forming an extremely thick retention layer on the pipe wall, which leads to thermal degradation. The central fluid forms a core crossflow, resulting in unreacted fluids being discharged. Simply increasing the pumping pressure or mechanical stirring will exacerbate the crossflow or break the macromolecular chains. This device coordinates the working rhythm of the feeding mechanism 2 and the ultrasonic intervention mechanism 3 through the controller. The servo motor 5 drives the external gear pump 6 as a power source to provide low-speed pulsating volumetric extrusion power for high-viscosity reactants, and pushes the material to flow in a laminar state along the axial direction in the main reaction pipeline 1. The piezoelectric ceramic transducer 7 emits high-frequency ultrasonic waves into the main reaction pipeline 1, and changes the rheological properties of the boundary layer fluid by using ultrasonic energy without increasing the overall mechanical shear force. The self-suppressing diffuser mechanism 4 utilizes an annular damping air chamber 14 formed by the diffuser shell 8 and the flexible bellows 9, in conjunction with the mechanical pressure relief valve 10, to absorb the pressure pulsation inside the fluid caused by standing wave resonance or viscosity change in a purely mechanical manner; this architecture, which works in synergy between macroscopic transport and microscopic media modification, eliminates the wall stagnation layer and maintains a constant pressure quasi-static environment in the flow channel. Taking the synthesis of ammonium polyphosphate as an example, the specific process parameters and equipment operating parameters are set as follows: The specific raw material formula for the synthesis reaction is phosphoric acid and urea, with a molar ratio of 1:1.5 to 1:2.5; a heating jacket is installed outside the main reaction pipeline 1 to control the reaction temperature range between 150℃ and 250℃. The servo motor 5 is set to a speed range of 10 r / min to 50 r / min to provide stable low-speed pulsating volumetric extrusion power; the piezoelectric ceramic transducer 7 emits ultrasonic waves at a specific operating frequency of 20 kHz to 40 kHz, with an initial duty cycle value set to 30% to 70%; the above parameter settings ensure the molecular weight consistency of flame retardant products such as ammonium polyphosphate. The output shaft of the servo motor 5 is directly connected to the drive gear shaft of the external gear pump 6 through a plum blossom-shaped flexible coupling 11. The discharge port of the external gear pump 6 is fixedly connected to the feed end of the main reaction pipeline 1 through a flange 12 and bolts 13. The main reaction pipeline 1 is made of stainless steel. A plum blossom-shaped flexible coupling 11 is used between the servo motor 5 and the drive gear shaft of the external gear pump 6 to transmit power with elastic buffering characteristics. The polymer elastomer inside the coupling can effectively absorb the torque impact and radial vibration caused by the centering error when the motor starts and the load changes, ensuring the stability of the output flow of the external gear pump 6. The discharge port of the external gear pump 6 is rigidly sealed to the feed end of the main reaction pipeline 1 through flange 12 and bolts 13. The flange 12 connection method can be replaced by clamp quick-connect connection or threaded sealing connection, as long as a leak-free connection of the high pressure fluid channel can be achieved. The main reaction pipeline 1 is made of stainless steel, which not only has chemical stability to resist corrosion of phosphorus and nitrogen acidic materials, but its rigid pipe wall can also serve as an excellent medium for sound wave conduction. Servo motor 5 drives external gear pump 6 to extrude material with low shear, and stainless steel reaction main pipeline 1 carries the material and propels it, avoiding shear degradation of the main material and providing stable initial flow field conditions for subsequent ultrasonic intervention. The piezoelectric ceramic transducer 7 is configured to generate high-frequency vibration and microcavitation effect in the boundary layer of the inner wall of the main reaction pipe 1 to disrupt the physical entanglement network of the reactants and generate a near-wall plug flow slip mode. The piezoelectric ceramic transducer 7 is attached to the outer wall of the stainless steel main reaction pipe 1, converting high-frequency electrical signals into high-frequency mechanical vibrations. These vibrations penetrate the pipe wall and induce micro-cavitation effects in the boundary layer fluid close to the inner wall surface. The periodic growth and transient collapse of the micro-cavitation bubbles generate strong local micro-jets, which instantaneously destroy the physical entanglement network of polymer materials on the inner wall surface of the main reaction pipe 1. The polymer melt has thixotropic properties. Under the continuous action of the micro-cavitation effect, the apparent viscosity of the fluid at the wall surface decreases sharply, exhibiting super-slippery characteristics, while the temperature and viscosity of the bulk fluid remain unchanged. The boundary layer liquefaction capability induced by the piezoelectric ceramic transducer 7, in conjunction with the basic axial thrust of the external gear pump 6, forces the high-viscosity fluid to change from the traditional parabolic velocity distribution to a plug flow slip distribution. The reactants are propelled forward as a whole in a plug flow pattern. If high-viscosity agglomerates appear locally, the ultrasonic waves automatically induce thixotropic liquefaction on their surface, allowing them to flexibly pass through narrow channels, eliminating wall retention and core crossflow, and achieving a uniform distribution of the residence time of the material in the main reaction pipeline 1. The flexible bellows 9 is made of polytetrafluoroethylene. The internal channel of the flexible bellows 9 is connected to the internal channel of the main reaction pipeline 1. The annular damping air chamber 14 is filled with compressed air. The flexible bellows 9 is configured to expand radially or stretch axially according to the pressure pulsation of the reactants. The diffuser shell 8 is spindle-shaped. The two ends of the diffuser shell 8 are fixedly connected to the main reaction pipeline 1 by welding. The diffuser shell 8 adopts a spindle-shaped structure that is large in the middle and small at both ends. Its two ends are fixed in series with the middle section of the main reaction pipeline 1 by welding. The welding method can be replaced by a high-pressure flange 12 bolt 13 group connection, as long as it can withstand the internal fluid static pressure. A flexible bellows 9 made of polytetrafluoroethylene is coaxially inserted inside the diffuser shell 8. Its excellent corrosion resistance and extremely low surface friction coefficient prevent material adhesion. The sealed annular damping air chamber 14 formed between the outer wall of the flexible bellows 9 and the inner wall of the diffuser shell 8 is filled with compressed air to form a pneumatic spring with a specific initial stiffness. When the material in the main reaction pipe 1 experiences pressure pulsation due to standing wave resonance or viscosity change, the PTFE flexible corrugated pipe 9 uses the fluid's own viscoelasticity as a feedback medium to compress the compressed air in the annular damping chamber 14 by radial expansion under pressure, or is stretched axially by the frictional drag force of the high-viscosity fluid. The spindle-shaped design of the diffuser shell 8 provides ample physical deformation space for the radial expansion of the flexible bellows 9. The deformation action of the polytetrafluoroethylene flexible bellows 9 converts the fluid kinetic energy into the gas chamber compression potential energy or mechanical displacement, and achieves automatic absorption of standing wave resonance pressure pulsation purely mechanically, thereby improving the equipment operation robustness of the continuous synthesis process.

[0020] Example 2: like Figure 4 As shown, a method for synthesizing a high-efficiency flame-retardant polymer additive includes: S1. Control the servo motor 5 to drive the external gear pump 6 to press the reactant into the main reaction pipeline 1, and control the piezoelectric ceramic transducer 7 to emit ultrasonic waves into the main reaction pipeline 1. S2. The instantaneous torque current signal of the servo motor 5 during the driving process, which is acquired in real time, is converted into the frequency domain using the Fast Fourier Transform algorithm, so as to extract and separate the amplitude of the higher harmonic components of its instantaneous torque current in real time. ; S3. Real-time extraction of acoustic impedance spectrum data of piezoelectric ceramic transducer 7 during operation. S4. Substitute the higher harmonic components and acoustic impedance spectrum data into the acoustic-mechanical coupled rheological model to derive and calculate the ratio of the storage modulus to the loss modulus of the current reactant. S5. Calculate the real-time average degree of polymerization of the reactants based on the ratio of storage modulus to loss modulus. This embodiment discloses the basic parameter acquisition and state evaluation logic of the control method based on the above-mentioned device; the servo motor 5 drives the external meshing gear pump 6 to continuously press the reactant into the main reaction pipeline 1, and the piezoelectric ceramic transducer 7 synchronously emits ultrasonic waves to establish a plug flow sliding flow field; the system extracts the high-order harmonic components of the instantaneous torque current of the servo motor 5 in real time during the driving process through electrical detection elements such as current transformers. These high-order harmonic components directly reflect the overall non-Newtonian fluid shear resistance fluctuation of the reactant. Simultaneously, the system extracts the acoustic impedance spectrum data of the piezoelectric ceramic transducer 7 during operation through the impedance analysis circuit. The phase shift change of the imaginary part in the acoustic impedance spectrum reveals the evolution of the local sound velocity and sound attenuation rate of the reactant. In addition, in order to obtain the current temperature data, a thermocouple temperature sensor 16 is attached to the outer wall of the main reaction pipe 1 to collect the current temperature of the reactant in real time. The high-order harmonic component characteristics of the instantaneous torque current and the acoustic impedance phase shift data are input into the acoustic-mechanical coupled rheological model. The model outputs the ratio of the storage modulus to the loss modulus of the current reactant by analyzing the coupling relationship between electrical and acoustic signals. The acoustic-mechanical coupled rheological model is used to calculate the real-time degree of polymerization of reactants. This model receives higher harmonic components and phase shift angle as inputs, calculates the macroscopic apparent viscosity and local acoustic attenuation coefficient, and constructs a dynamic modulus based on physical constitutive relations. The specific mathematical derivation and processing flow are as follows: Based on the amplitude of the higher harmonic components of the extracted instantaneous torque current In this embodiment, the amplitude of the third harmonic component, which is most sensitive to changes in viscosity load of non-Newtonian fluids, is specifically selected to eliminate fundamental interference. The macroscopic apparent viscosity of the reactants is then derived using a preset electromechanical conversion coefficient. The calculation formula is as follows:

[0021] in, The preset electromechanical conversion coefficient is obtained by pre-calibrating and correcting the ratio of the torque constant of the servo motor 5 to the displacement of the external gear pump 6 using a standard viscosity fluid at the same temperature and speed. The amplitude of the higher harmonic components of the instantaneous torque current; This refers to the real-time rotational speed of servo motor 5; Based on the phase shift angle in acoustic impedance spectroscopy data Combined with the propagation distance of ultrasound within the main reaction pipe 1 , here Specifically, it refers to the inner diameter of the main reaction pipe 1, representing the path length of the ultrasonic waves radially penetrating the material, and derives the local acoustic attenuation coefficient. The calculation formula is as follows:

[0022] in, This is the operating angular frequency of the ultrasonic wave. The controller obtains the reference sound velocity of the reactants at the current temperature by interpolating from a pre-stored temperature-reference sound velocity table based on the current temperature collected by thermocouple temperature sensor 16. The accurate value is obtained; the relationship table is specifically generated by measuring the propagation speed of ultrasound in the above-mentioned polydimethylsiloxane standard oil in the temperature range of 150℃ to 250℃ in advance and fitting it. Based on the physical constitutive equation of linear viscoelasticity theory, a dynamic modulus equation in the complex domain is constructed. The model incorporates dimensionless conversion coefficients calibrated using standard fluids. Macroscopic apparent viscosity Associated with the imaginary part to characterize viscous loss, the local acoustic attenuation coefficient is... The dynamic modulus equation, which is related to the real part to characterize shear elastic energy storage, is as follows:

[0023] in, For energy storage modulus, For loss modulus, The imaginary unit, For material density,

[0024] The reference sound velocity of the reactants at the current temperature. To obtain the dimensionless system intrinsic constants obtained through preliminary experimental calibration under the same ultrasonic conditions, The local sound attenuation coefficient, The dynamic shear modulus of the calibration fluid at the corresponding temperature is used to measure the propagation distance of the aforementioned ultrasonic waves within the main reaction pipe 1. and Given the standard data, the specific calibration steps are as follows: The standard oil of polydimethylsiloxane was pumped into the main reaction pipeline 1. The acoustic impedance phase shift angle and the high-order harmonic current of the motor were recorded at ultrasonic frequencies from 20kHz to 40kHz. These values ​​were then substituted into the formula to calculate... The value is introduced in the formula to offset the spatial attenuation dimension L−1 of the local sound attenuation coefficient α. Let be the shear angular frequency of the fluid flow, and its calculation formula is:

[0025] in, This refers to the real-time rotational speed of the servo motor. The displacement per revolution of the external gear pump 6 Pi Let be the inner diameter of the main reaction pipe 1; by separating the real and imaginary parts of the equation, the ratio of the storage modulus to the loss modulus of the current reactant is calculated. :

[0026] Storage modulus represents the elastic characteristics of a material, while loss modulus represents its viscous characteristics. This ratio... The degree of polymerization of the reactants changes regularly with the growth of the macromolecular chains. Based on this, the current real-time average degree of polymerization of the reactants can be calculated. The specific calculation process is as follows: the system has pre-stored an empirical mapping curve or data lookup table of the ratio of storage modulus to loss modulus of the reactants under the current operating conditions, corresponding to the average degree of polymerization. The calculated ratio is substituted into the fitting polynomial formula of the empirical mapping curve, or linear interpolation is performed in the data lookup table to accurately calculate the current real-time average degree of polymerization of the reactants. The specific calibration method for the empirical mapping curve is as follows: Under the same process conditions, multiple sets of offline polymerization experiments are conducted, and the true average degree of polymerization of the reactants is tested periodically using a gel permeation chromatography instrument. The ratio of storage modulus to loss modulus calculated by the system is recorded simultaneously. ;by The actual average aggregation degree is the independent variable. Using the least squares method as the dependent variable, a fit is obtained as follows: The polynomial formula for , where, It is the ratio of storage modulus to loss modulus; storage modulus represents the elastic characteristics of a material. The fitting coefficients are stored in the controller as a conversion benchmark; the real-time average aggregation degree obtained from the conversion is used to provide data support for subsequent rheological control. The steps following S5 include: S601. Obtain the preset optimal reaction path curve, compare the real-time average degree of polymerization with the corresponding value on the optimal reaction path curve, and calculate the degree of polymerization deviation value. S602. If the real-time average degree of polymerization shown by the polymerization degree deviation value is lower than the corresponding value, control and increase the working duty cycle of the piezoelectric ceramic transducer 7, and use the acoustic flow effect after increasing the working duty cycle to enhance micro-mixing and accelerate the reaction. S603. If the real-time average degree of polymerization deviation value is higher than the corresponding value, control the reduction of the working frequency of the piezoelectric ceramic transducer 7, and at the same time control the increase of the speed of the servo motor 5 to accelerate the outflow of the reaction material from the main reaction pipeline 1. S604. If the absolute value of the difference between the real-time average degree of polymerization and the corresponding value is less than or equal to the preset allowable error threshold, the current control parameter remains unchanged. The system retrieves the optimal reaction path curve pre-stored in the memory. This curve calibrates the target degree of polymerization of the material at each position in the flow channel under ideal conditions. The specific method for obtaining the optimal reaction path curve is as follows: For specific reactants such as ammonium polyphosphate, reaction kinetics tests are conducted under ideal mass and heat transfer conditions in the laboratory to obtain the ideal average degree of polymerization data points of the material at different reaction times. The optimal reaction path curve distributed with the position of the flow channel is generated by fitting smooth splines. The derived real-time average degree of polymerization is compared with the corresponding value on the optimal reaction path curve, and the difference is calculated to output the degree of polymerization deviation value. If the degree of polymerization deviation value is negative, that is, the real-time average degree of polymerization is lower than the corresponding value, it indicates that the current local polymerization rate is lagging. The system immediately sends a command to the drive circuit of the piezoelectric ceramic transducer 7 to control and increase its working duty cycle. The enhanced acoustic flow effect intensifies the micro-mixing and mass transfer efficiency inside the reactants, and promotes the monomer to diffuse and combine towards the end of the macromolecular chain at an accelerated pace. If the degree of polymerization deviation is positive, meaning the real-time average degree of polymerization is higher than the corresponding value, it indicates that the reaction is too fast and there is a risk of cross-linking and gelation. The system sends a frequency reduction command to the piezoelectric ceramic transducer 7 to weaken the acoustic flow effect, and at the same time sends an acceleration command to the driver of the servo motor 5 to speed up the flow of high-viscosity material out of the main reaction pipe 1 and shorten its residence time in the high-temperature zone. To achieve precise quantitative adjustment, the control process specifically adopts an incremental proportional-integral-derivative control algorithm. The controller adjusts the degree of polymerization deviation value according to the specific parameters of the reaction. Calculate the adjustment increment of duty cycle or speed:

[0027] in, At the current sampling time, These are the proportional, integral, and differential coefficients, respectively. This represents the aggregation deviation value at the current sampling time. This represents the aggregation degree deviation value at the previous sampling time. This represents the aggregation degree deviation value at the previous sampling time. The increment is adjusted for general control variables; in actual control logic, when At that time, Specifically, this is mapped to the adjustment increment of the operating duty cycle of the piezoelectric ceramic transducer 7; when At that time, Specifically, this is mapped to the increase in the rotational speed of the servo motor 5 and the decrease in the operating frequency of the piezoelectric ceramic transducer 7. This control strategy abandons the traditional approach of adjusting temperature parameters with extremely high thermal inertia. Instead, it uses instantaneous ultrasonic and flow velocity fields for quantitative intervention, ensuring that the degree of polymerization of ammonium polyphosphate always falls within the preset narrow distribution error envelope, thus avoiding system failure caused by incomplete reaction or excessive cross-linking. The flexible bellows 9 and the annular damping air chamber 14 in the self-suppressing and diffuser mechanism 4 constitute a pressure response system. After step S1, the following steps are included: S801. When a positive pressure peak is generated inside the reactant, the flexible bellows 9 is compressed and expands radially outward to compress the air in the annular damping chamber 14, causing the cross-section of the fluid channel to change in a Venturi-like manner, and increasing the local flow channel volume through radial expansion to absorb the pressure pulse energy. S802. When the viscosity of the reactant increases sharply, leading to an increase in axial frictional drag, the flexible bellows 9 is stretched axially. S803, the axial stretching action of the flexible bellows 9 pulls the mechanical pressure relief valve 10 slightly open through the connecting rod 15, reducing the stiffness of the annular damping air chamber 14 to absorb pressure pulsation. Under the combined action of pulsating extrusion and ultrasonic cavitation, standing wave resonance inevitably occurs inside the reactant material, which triggers local high-frequency pressure pulsation. In order to separate the mutual interference between the fluid normal pressure pulsation and the tangential friction drag force on the corrugated pipe deformation, the flexible corrugated pipe 9 is embedded with anisotropic high-strength tensile fibers inside the pipe wall, so that it has high initial yield stiffness in the axial direction and maintains high flexibility in the radial direction. To achieve a firm embedding of aramid fibers inside the polytetrafluoroethylene tube wall, the specific manufacturing process is as follows: the surface of the aramid fibers is chemically etched using a sodium naphthalene complex solution to significantly improve its surface energy and roughness. The treated aramid fibers were woven into a skeleton using a winding process, and then impregnated in a polytetrafluoroethylene dispersion containing a silane coupling agent; the skeleton was then pressed into a tube blank using an isostatic pressing process. to High-temperature sintering is carried out at a certain temperature to melt polytetrafluoroethylene and fully encapsulate and penetrate into the aramid fiber skeleton. After cooling, a flexible corrugated tube 9 with aramid fibers embedded inside is obtained. The initial compressed air pressure of the annular damping chamber 14 is set to 0.2MPa to 0.5MPa to provide suitable initial air pressure spring stiffness. When a positive pressure peak is generated inside the fluid, due to the constraint of the axial high-stiffness fiber, the PTFE flexible bellows 9 only undergoes radial expansion outward under pressure, squeezing the compressed air in the annular damping chamber 14. The chamber pressure rises and generates a reverse antagonistic force to counteract the outward pressure wave. Although the Venturi-like change in the cross-section of the fluid channel will convert some of the dynamic pressure into static pressure, the outward radial expansion of the flexible bellows 9 under pressure significantly increases the local flow channel volume. Based on the pressure buffering mechanism of volume compensation, the absorption effect of this volume expansion on the pressure pulse energy is dominant, overcoming the static pressure rise effect caused by the conversion of dynamic pressure. Therefore, it directly absorbs the pressure pulse energy of the fluid, promotes the overall decrease of local static pressure, and thus effectively suppresses the positive pressure peak. When the local reaction is too fast and the viscosity of the reactant increases dramatically, the axial frictional drag force generated by the high viscosity fluid on the inner wall of the flexible bellows 9 increases significantly. This tangential frictional force acts directly on the pipe wall and accumulates. When the total drag force exceeds the initial yield stiffness threshold of the embedded fiber, it forces the flexible bellows 9 to overcome its own structural stiffness and undergo axial tensile deformation. The axial tensile displacement of the flexible bellows 9 is mechanically transmitted through the rigid connecting rod 15, which physically pulls the valve core of the mechanical pressure relief valve 10 installed on the side wall of the diffuser housing 8 to open slightly, discharge some compressed air to reduce the overall stiffness of the annular damping air chamber 14, so that the bellows has a greater deformation tolerance to absorb excess pressure pulsation. This purely mechanical negative feedback regulation mechanism does not require the participation of complex electronic sensors. It uses the physical changes of the fluid itself to drive the movement of the structural components, maintaining a constant pressure gradient within the main reaction pipeline 1, and demonstrating a high degree of environmental adaptability under complex chemical synthesis conditions. To further verify the technical effectiveness of the device and method of the present invention, the following comparative experiment on the continuous synthesis of ammonium polyphosphate was conducted: The control group used a traditional tubular reactor without ultrasonic intervention or a self-suppressing and diffusion mechanism, and extruded at a constant speed. The experimental group used the device and dynamic control method of this invention. The specific raw material formula for the synthesis reaction was phosphoric acid and urea in a molar ratio of 1:2, and the reaction temperature was set at 200℃. Test index 1: Molecular weight distribution index; weight-average molecular weight was measured by gel permeation chromatography after timed sampling. Number-average molecular weight The calculation formula is as follows:

[0028] in, It is the molecular weight distribution index. This is the weight-average molecular weight. The number average molecular weight was [value missing]; the test results showed that the control group product [value missing]. The average value was 2.85, with a wide distribution. Furthermore, disassembly after the reaction revealed a thermally degraded carbonized residue layer approximately 2 mm to 3 mm thick on the tube wall; while the experimental group's product... The average value decreased significantly and stabilized at 1.15, with an extremely narrow distribution, and the inner wall of the main reaction channel was smooth with no residue layer. Test index 2: Dwell time distribution; the dimensionless variance was calculated using the pulse tracer method. The smaller the variance value, the closer the flow field is to an ideal piston flow; experiments show that the dimensionless variance of the experimental group... It decreased by 82% compared to the control group; The above comparative experimental data fully demonstrate that, without increasing mechanical shear force, this invention achieves ultrasonic plug flow sliding and is based on... The dynamic polymerization degree closed-loop control eliminates core crossflow and wall retention, greatly improving the uniformity of the continuous polymerization reaction of high viscosity additives.

[0029] This application has been described through the above embodiments; however, it should be understood that the above embodiments are for illustrative purposes only and are not intended to limit this application to the described embodiments. Those skilled in the art will understand that many more variations and modifications can be made based on the teachings of this application, and all such variations and modifications fall within the scope of protection claimed in this application.

Claims

1. A high-efficiency flame-retardant polymer additive synthesis reaction apparatus, characterized in that, include: The main reaction pipeline (1), feeding mechanism (2), ultrasonic intervention mechanism (3), self-suppressing and diffuser mechanism (4), and controller; The main reaction pipeline (1) is a hollow cylindrical straight pipe, which serves as the foundation for the flow of reactants; The feeding mechanism (2) is located at the feed end of the main reaction pipeline (1), including a servo motor (5) and an external gear pump (6). The output shaft of the servo motor (5) is connected to the drive gear shaft of the external gear pump (6), and the outlet of the external gear pump (6) is connected to the main reaction pipeline (1). The self-suppressing diffuser (4) is connected in series in the middle section of the main reaction pipeline (1), including a hollow diffuser shell (8) that is large in the middle and small at both ends, a flexible bellows (9) and a mechanical pressure relief valve (10). The flexible bellows (9) is coaxially inserted inside the diffuser shell (8) and sealed at both ends. A sealed annular damping chamber (14) is formed between the outer wall of the flexible bellows (9) and the inner wall of the diffuser shell (8). The mechanical pressure relief valve (10) is installed on the diffuser shell (8) and connected to the chamber (14). Its valve core is connected to the outer wall of the flexible bellows (9) through a connecting rod (15). The ultrasonic intervention mechanism (3) includes a piezoelectric ceramic transducer (7), which is attached to the outer wall of the main reaction pipe (1) along the axial and circumferential directions for transmitting high-frequency ultrasonic waves into the pipe; the controller controls the servo motor (5) and the piezoelectric ceramic transducer (7).

2. The high-efficiency flame-retardant polymer additive synthesis reaction apparatus according to claim 1, characterized in that, The output shaft of the servo motor (5) is directly connected to the drive gear shaft of the external gear pump (6) through a plum blossom-shaped flexible coupling (11). The outlet of the external gear pump (6) is fixedly connected to the feed end of the main reaction pipeline (1) through a flange (12) and bolts (13).

3. The high-efficiency flame-retardant polymer additive synthesis reaction apparatus according to claim 1, characterized in that, The piezoelectric ceramic transducer (7) is configured to generate high-frequency vibration and microcavitation effect in the boundary layer of the inner wall of the main reaction pipe (1) to disrupt the physical entanglement network of the reactants and generate a near-wall plug flow slip mode.

4. The high-efficiency flame-retardant polymer additive synthesis reaction apparatus according to claim 1, characterized in that, The flexible corrugated pipe (9) is made of polytetrafluoroethylene. The internal channel of the flexible corrugated pipe (9) is connected to the internal channel of the main reaction pipe (1). The annular damping air chamber (14) is filled with compressed air. The flexible corrugated pipe (9) is configured to expand radially or stretch axially according to the pressure pulsation of the reactants.

5. The high-efficiency flame-retardant polymer additive synthesis reaction apparatus according to claim 1, characterized in that, The main reaction pipeline (1) is made of stainless steel.

6. The high-efficiency flame-retardant polymer additive synthesis reaction apparatus according to claim 1, characterized in that, The diffuser shell (8) is spindle-shaped, and its two ends are fixedly connected to the main reaction pipeline (1) by welding.

7. A method for synthesizing a high-efficiency flame-retardant polymer additive, applied to the high-efficiency flame-retardant polymer additive synthesis apparatus described in claim 1, characterized in that, include: S1. Control the servo motor (5) to drive the external meshing gear pump (6) to press the reactant into the main reaction pipeline (1), and control the piezoelectric ceramic transducer (7) to emit ultrasonic waves into the main reaction pipeline (1); S2. The instantaneous torque current signal of the servo motor (5) during the driving process is converted into the frequency domain by the fast Fourier transform algorithm in real time, so as to extract and separate the amplitude of the higher harmonic components of the instantaneous torque current in real time. ; S3. Real-time extraction of acoustic impedance spectrum data of the piezoelectric ceramic transducer (7) during operation; S4. Substitute the higher harmonic components and the acoustic impedance spectrum data into the acoustic-mechanical coupled rheological model to derive and calculate the ratio of the storage modulus to the loss modulus of the current reactant. S5. The real-time average degree of polymerization of the reactants is obtained by converting the ratio of the storage modulus to the loss modulus.

8. The method for synthesizing a high-efficiency flame-retardant polymer additive according to claim 7, characterized in that, The step S5 is followed by: S601. Obtain the preset optimal reaction path curve, compare the real-time average degree of polymerization with the corresponding value on the optimal reaction path curve, and calculate the degree of polymerization deviation value. S602. If the polymerization degree deviation value shows that the real-time average polymerization degree is lower than the corresponding value, control the increase of the working duty cycle of the piezoelectric ceramic transducer (7) and use the acoustic flow effect after increasing the working duty cycle to enhance micro-mixing and accelerate the reaction. S603. If the polymerization degree deviation value shows that the real-time average polymerization degree is higher than the corresponding value, control the reduction of the working frequency of the piezoelectric ceramic transducer (7) and at the same time control the increase of the rotation speed of the servo motor (5) to speed up the outflow of the reaction material from the main reaction pipeline (1). S604. If the absolute value of the difference between the real-time average degree of aggregation and the corresponding value is less than or equal to the preset allowable error threshold, the current control parameters remain unchanged.

9. The method for synthesizing a high-efficiency flame-retardant polymer additive according to claim 7, characterized in that, The step S5 is followed by: S701. Obtain the preset optimal reaction path curve, compare the real-time average degree of polymerization with the corresponding value on the optimal reaction path curve, and calculate the degree of polymerization deviation value. S702. If the polymerization degree deviation value shows that the real-time average polymerization degree is higher than the corresponding value, control the reduction of the working frequency of the piezoelectric ceramic transducer (7) and at the same time control the increase of the rotation speed of the servo motor (5) to speed up the outflow of the reaction material from the main reaction pipeline (1). S703. If the degree of polymerization deviation value shows that the real-time average degree of polymerization is equal to or lower than the corresponding value, the current control parameters remain unchanged.

10. The method for synthesizing a high-efficiency flame-retardant polymer additive according to claim 7, characterized in that, The flexible bellows (9) in the self-suppressing diffuser mechanism (4) and the annular damping air chamber (14) constitute a pressure response system. The step S1 is followed by: S801. When a positive pressure peak is generated inside the reactant, the flexible bellows (9) is compressed and expands radially outward to compress the air in the annular damping chamber (14), so that the cross section of the fluid channel changes in a Venturi-like manner, and the local flow channel volume is increased by radial expansion to absorb the pressure pulse energy. S802. When the viscosity of the reactant increases sharply, causing the axial frictional drag force to increase, the flexible corrugated pipe (9) is stretched along the axial direction. S803, the axial stretching action of the flexible bellows (9) pulls the mechanical pressure relief valve (10) slightly open through the connecting rod (15), reducing the stiffness of the annular damping air chamber (14) to absorb pressure pulsation.

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