Cyclohexanone-oxime transposition process flow and device with sulfuric acid concentration supply in different regions

Abstract

The invention provides a cyclohexanone-oxime transposition process flow and a cyclohexanone-oxime transposition device for partitioned sulfuric acid concentration supply, which are used for partitioned supply and accurate control of sulfuric acid concentration in different stages of transposition reaction, in the transposition process flow, fuming sulfuric acid is proportionally distributed to a high-concentration acid channel and a low-concentration acid channel through an intelligent metering and acid adding module, and the high-concentration acid channel and the low-concentration acid channel are communicated with the high-concentration acid channel and the low-concentration acid channel; the high-concentration acid channel is used for a one-step transposition reactor of a one-step reaction zone of the two-step transposition process, the low-concentration acid channel is used for a two-step transposition reactor of a two-step reaction zone of the two-step transposition process, and in the transposition process flow, a multi-mode fuzzy self-adaptive prediction PID control algorithm is adopted, control modes are switched according to reaction stages, and the multi-mode fuzzy self-adaptive prediction PID control algorithm is adopted. The first-step reaction zone adopts high-precision temperature-acid concentration cascade control, and the second-step reaction zone adopts by-product prediction feedforward control; according to the invention, partitioned supply and accurate control of sulfuric acid concentration in the first-step reaction zone and the second-step reaction zone can be realized, the reaction efficiency and selectivity are improved, and acid consumption and by-product generation are reduced.

Description

Technical Field

[0001] This invention relates to the field of chemical process technology, and in particular to a process flow and apparatus for cyclohexanone oxime transposition with zoned sulfuric acid concentration supply, specifically a process flow and apparatus for cyclohexanone oxime transposition with zoned sulfuric acid concentration supply. Background Technology

[0002] Caprolactam is an important chemical raw material, mainly produced through the Beckmann rearrangement reaction of cyclohexanone oxime. Currently, industrial production primarily employs a two-step transposition process. Cyclohexanone oxime reacts with excess fuming sulfuric acid in a one-step transposition reactor, and the product then enters the two-step transposition reactor. The main problem with existing technology is that the product from the one-step transposition reaction directly enters the two-step transposition reactor and mixes completely with the internal liquid, leading to a significant decrease in the concentration of fuming sulfuric acid, reduced sulfuric acid utilization, and increased side reactions. Traditional processes use a single-pipe external circulation, which cannot precisely control the sulfuric acid concentration in the one-step and two-step zones, resulting in low reaction efficiency and high acid consumption. Therefore, there is an urgent need in this field for a process flow and apparatus capable of precisely controlling the sulfuric acid concentration in different stages of the transposition reaction to improve reaction efficiency and reduce acid consumption and by-product formation. Summary of the Invention

[0003] This invention proposes a process and apparatus for cyclohexanone oxime transposition with zoned sulfuric acid concentration supply. It provides a solution to the problems of existing cyclohexanone oxime transposition processes, such as the inability to control the sulfuric acid concentration in zones, low utilization rate, and numerous side reactions. It can achieve zoned supply and precise control of sulfuric acid concentration in the first-step reaction zone and the second-step reaction zone, thereby improving reaction efficiency and selectivity, and reducing acid consumption and by-product formation.

[0004] The present invention adopts the following technical solution.

[0005] A process flow for the transposition of cyclohexanone oxime with zoned sulfuric acid concentration supply is disclosed. In the two-step transposition process of cyclohexanone oxime preparation, this process is used to precisely control and supply sulfuric acid concentration at different stages of the transposition reaction. In this process, fuming sulfuric acid is proportionally distributed to a high-concentration acid channel and a low-concentration acid channel via an intelligent metering and acid addition module. The high-concentration acid channel is used in the first-step transposition reactor of the first-step reaction zone in the two-step transposition process, while the low-concentration acid channel is used in the second-step transposition reactor of the second-step reaction zone. The process employs a multimodal fuzzy adaptive predictive PID control algorithm, switching control modes according to the reaction stage. The first-step reaction zone uses high-precision temperature-acid concentration cascade control, while the second-step reaction zone uses byproduct prediction feedforward control.

[0006] The transposition process uses a cyclohexanone oxime transposition device with a zoned sulfuric acid concentration supply including an online acid concentration-flow coupling control system (4). The multimodal fuzzy adaptive predictive PID control algorithm is executed by the multimodal adaptive predictive PID controller (43) of the online acid concentration-flow coupling control system. The indexing process includes the following steps; Step 1: Distribute the fuming sulfuric acid to the high-concentration acid channel (31) and the low-concentration acid channel (32) in proportion through the intelligent metering acid addition module (7). Step 2: Cyclohexanone oxime enters a one-step transposition reactor (1) and undergoes a Beckmann rearrangement reaction with high-concentration sulfuric acid, controlling the reaction temperature at 85-95℃ and maintaining the sulfuric acid concentration at 25-28%; Step 3: The product of the first step reaction enters the degassing-liquid mixing unit (6), where it first passes through the degassing section (61) to remove entrained gas, and then passes through the liquid mixing section (62) to be mixed with the second step circulating liquid in proportion. Step 4: The mixture enters the two-step displacement reactor (2), and the reaction temperature is controlled at 95-105℃, while the sulfuric acid concentration is adjusted to 18-22%. Step 5: Monitor and adjust the acid concentration and flow rate of each channel in real time through the online acid concentration-flow coupling control system (4); Step 6: The reaction products are cooled by the external circulation cooling unit (5) and then output. Part of the reaction products are output as products, and the other part is returned to the system as a second-step circulating liquid.

[0007] The execution of the multimodal fuzzy adaptive predictive PID control algorithm includes the following steps; Step S1: Multimodal switching and data acquisition; Step S2: Adjustment of fuzzy adaptive parameters; Step S3: Based on the calculation of the feedforward compensation, establish a reaction kinetics prediction model; Step S4: Incremental digital PID calculation and final control quantity synthesis; Step S5, safety interlock and parameter self-learning, specifically: if the predicted value of by-products... If the safety threshold is exceeded multiple times consecutively, or the temperature T exceeds 125℃ or the pressure P exceeds 0.5MPa, the safety procedure is triggered, and the acid source is isolated within 0.5 seconds through the emergency shut-off valve (73) of the intelligent metering acid addition module. The system uses historical operating data to fine-tune the prediction model once a month (online learning) to adapt to the slow process of catalyst activity change and ensure control accuracy.

[0008] In step S1, the controller collects system state variables in real time, including the actual value of acid concentration in the first-stage reactor. Actual acid concentration in the two-step reactor One-step reactor temperature Two-step reactor temperature and estimated rates of byproduct formation. The setpoints include the acid concentration setpoint for the one-step reactor. (25-28%) Acid concentration setpoint for the two-step reactor (18-22%) Temperature setpoint and byproduct rate safety threshold (≤3%); Calculation error signal: acid concentration error Temperature error Byproduct deviation According to the error Automatic size switching control mode: When At this time, the system is in one-step reaction mode, with the priority being to maintain a high acid concentration to improve the conversion rate; when When the system switches to a two-step reaction mode, the priority is to suppress side reactions and optimize selectivity.

[0009] In step S2, the fuzzy inference engine calculates the error... and error change rate Dynamically adjust the parameters of the PID controller The blurring process performed in step S2 specifically involves: […]. and The precise values ​​are mapped to fuzzy sets, such as {Negative Large (NB), Negative Medium (NM), Negative Small (NS), Zero (ZO), Positive Small (PS), Positive Medium (PM), Positive Large (PB)}; their membership functions adopt trigonometric functions, expressed by the formula: in, For fuzzy sets, The center point of the membership function, The width parameter; the defuzzification process in step S2 specifically involves calculating the parameter adjustment amount using the centroid method, with the following formula: in, Let i be the activation value of the i-th rule. The center value of the corresponding output fuzzy set is given by the formula: in These are the initial parameters tuned using the Ziegler-Nichols method, etc.

[0010] Step S3 includes the following: A simplified reactor state-space model was established to predict byproduct trends: in, This refers to the concentration of cyclohexanone oxime. The byproduct concentration is given, u is the control input (acid pump speed or valve opening), and k1 to k4 are the reaction rate constants. An extended Kalman filter (EKF) is used for state estimation and prediction. in, Let be the Jacobian matrix, and Q and R be the covariance matrices of process noise and measurement noise, respectively. Predict the byproduct formation rate in the third step (15 seconds later). If the predicted value exceeds the safety threshold. Then the feedforward compensation amount is generated: in, This is the feedforward compensation gain (tuned experimentally).

[0011] Step S4 includes the following: The feedback control quantity is calculated using an incremental digital PID algorithm. To avoid integral saturation, the formula is as follows: The final control quantity is the sum of the feedback control quantity and the feedforward compensation quantity, expressed by the formula: This control quantity The output is sent to the actuator, which includes the variable frequency metering pump (72) of the intelligent metering acid addition module and the bypass temperature control valve (53) of the external circulation cooling unit.

[0012] In step two, the one-step transposition reaction time is controlled within 5-8 minutes; in step four, the two-step transposition reaction time is controlled within 10-15 minutes. The mixing ratio in step three is precisely controlled by the proportioning mixing valve of the liquid preparation section (62), and the volume ratio of the first-step reaction product to the second-step circulating liquid is 1:3-1:5.

[0013] A cyclohexanone oxime transposition device with zoned sulfuric acid concentration supply is used to operate the cyclohexanone oxime transposition process with zoned sulfuric acid concentration supply described above. The transposition device includes a one-step transposition reactor (1), a two-step transposition reactor (2), a dual-channel external circulation output pipe (3), an online acid concentration-flow coupling control system (4), an external circulation cooling unit (5), a degassing-liquid mixing unit (6), and an intelligent metering acid addition module (7). The dual-channel external circulation output pipe splits the traditional single pipe into a high-concentration acid channel and a low-concentration acid channel, which are independently connected to the one-step transposition reactor and the two-step transposition reactor, respectively, to achieve zoned supply of sulfuric acid concentration and avoid global dilution. The one-step transposition reactor (1) is equipped with a high acid concentration inlet (11) and a one-step reaction product outlet (12). The two-step shift reactor (2) is equipped with a two-step shift reactor mixer (21) and a liquid preparation device (22). The dual-channel external circulation output pipe (3) is divided into a high-concentration acid channel (31) and a low-concentration acid channel (32), which are independently connected to the one-step shift reactor (1) and the two-step shift reactor mixer (21). The two ends of the high-concentration acid channel are connected to the high-concentration inlet of the one-step shift reactor and the liquid preparation device of the two-step shift reactor, respectively. The outlet of the first-step reaction product of the one-step displacement reactor is connected to the two-step displacement reactor via a low-concentration acid channel, an online acid concentration-flow coupling control system, and a degassing-liquid mixing unit. The online acid concentration-flow coupling control system (4) consists of a refractometer (41), a mass flow meter (42) and a multimodal fuzzy adaptive PID controller (43), which monitors and adjusts the acid concentration and flow rate in real time; it controls the acid concentration and flow rate in a closed loop, so that the acid concentration in the first step zone is kept at a high value to improve the conversion rate, and the acid concentration in the second step zone is appropriately reduced to optimize selectivity. The online acid concentration-flow coupling control system is connected to the intelligent metering acid addition module; Installation and sampling of refractometer (41): Refractometer (41) is an online insertion type. Its sensing probe is directly installed on the circulating liquid outlet pipe of the two-step displacement reactor (2). The installation position is located before the inlet of the external circulation pump (51) to ensure the representativeness of the sampling. The probe is inserted to a depth of 1 / 3 of the pipe diameter to avoid close contact with the pipe wall to measure the acid concentration of the main stream. The system is set to automatically perform a sampling measurement every 5 seconds to obtain the analog signal (4-20mA) of sulfuric acid concentration (calculated as SO3) in real time and transmit the signal to the multimodal fuzzy adaptive PID controller (43). Installation and measurement of mass flow meter (42): The mass flow meter (42) is installed on the pipeline of the low concentration acid channel (32) at the rear end of the variable frequency metering pump (72) in the intelligent metering acid addition module (7). When it is working, it directly measures the mass flow rate of sulfuric acid flowing through the channel and outputs a 4-20mA analog signal to the multimodal fuzzy adaptive PID controller (43). This installation position can accurately measure the flow rate of low concentration acid that is about to enter the two-step reaction zone, providing key feedback for control.

[0014] The refractometer (41) and mass flow meter (42) serve as the "sensors" of the system, continuously transmitting the real-time monitored acid concentration and flow signals to the analog input (AI) module of the multimodal fuzzy adaptive PID controller (43) via shielded signal cables; the multimodal fuzzy adaptive PID controller (43) compares the received signal with the internally set target value (such as the two-step reactor acid concentration set value c2, sp=20%), the target value including the two-step reactor acid concentration set value c2, and generates an error signal e(t); The error signal e(t) and its rate of change ec(t) are the direct inputs to the control algorithms in steps S1 and S2; the specific connection logic is as follows: The multimodal fuzzy adaptive PID controller (43) first performs multimodal switching and data acquisition in step S1, compares the received c2(t) with c2 and sp, and determines whether the system is in a one-step or two-step reaction mode. Subsequently, in step S2. Fuzzy adaptive parameter adjustment, the PID parameters (Kp, Ki, Kd) are dynamically tuned using e(t) and ec(t). Finally, the multimodal fuzzy adaptive controller (43) sends a control signal (such as 4-20mA) to the variable frequency metering pump (72) through its analog output based on the calculation results, instructing it to adjust its speed, thereby changing the amount of sulfuric acid added, and realizing the complete closed-loop control of "monitoring-calculation-adjustment".

[0015] The external circulation cooling unit (5) consists of an external circulation pump (51), an external circulation cooler (52), and a bypass temperature control valve (53); it is used for constant temperature and coordinated acid concentration control. The two-step rotation reactor is connected to the external circulation cooling unit; The degassing-liquid mixing unit (6) includes a degassing section (61) and a liquid mixing section (62). The degassing section (61) is equipped with a gas separation device, and the liquid mixing section (62) is equipped with a proportional mixing valve. When the transposition device is working, the first step product of the cyclohexanone oxime transposition process is first degassed by the degassing-liquid mixing unit to remove entrained gas, and then mixed with the second step circulating liquid in proportion in the liquid mixing section of the degassing-liquid mixing unit to prevent a sudden drop in acid concentration. The intelligent metering acid addition module (7) includes a sulfuric acid storage tank (71), a frequency conversion metering pump (72), and an emergency shut-off valve (73), which is used to receive instructions from the control system to achieve accurate metering and emergency isolation of sulfuric acid; The liquid preparation device (22) has an upward-facing opening, with its upper part being a trumpet-shaped tube whose diameter decreases from top to bottom, and its lower part being a cylindrical tube that smoothly transitions to the upper part. The degassing section (61) includes a shell (611), a guide plate (612) and a baffle plate (613). The guide plate is fixed on the top of the shell, with one side being the exhaust zone and the other side being the guide zone. The volume of the exhaust zone is greater than the volume of the guide zone.

[0016] This invention proposes a cyclohexanone oxime transposition process and apparatus with zoned sulfuric acid concentration supply. The apparatus consists of a one-step transposition reactor, a two-step transposition reactor, a dual-channel external circulation output pipe, an online acid concentration-flow coupling control system, an external circulation cooling unit, a degassing-liquid mixing unit, and an intelligent metering acid addition module. The dual-channel external circulation output pipe splits the traditional single-pipe system into a high-concentration acid channel and a low-concentration acid channel, which are independently connected to the one-step reaction zone and the two-step mixer, respectively, achieving zoned sulfuric acid concentration supply and avoiding global dilution. The online acid concentration-flow coupling control system consists of a refractometer, a mass flow meter, and a multimodal fuzzy adaptive PID controller, which controls the acid concentration and flow rate in a closed loop, maintaining a high acid concentration in the one-step zone to improve conversion rate, and moderately reducing the acid concentration in the two-step zone to optimize selectivity. The external circulation cooling unit consists of an external circulation pump, an external circulation cooler, and a bypass temperature control valve, maintaining constant temperature and coordinating with acid concentration control. The degassing-liquid mixing unit includes a degassing section and a liquid mixing section. The first-step product is degassed to remove entrained gases, and then mixed with the second-step circulating liquid in a proportional manner in the liquid mixing section to prevent a sudden drop in acid concentration. The intelligent metering acid addition module includes a sulfuric acid storage tank, a variable frequency metering pump, and an emergency shut-off valve. It receives commands from the control system to achieve precise metering and emergency isolation of sulfuric acid. This invention can shorten reaction time, reduce by-products, and significantly improve the overall energy efficiency and selectivity of the device.

[0017] Compared with the prior art, the present invention has the following beneficial effects: 1. Improved sulfuric acid utilization: By supplying sulfuric acid through dual-channel partitions, the first-step zone maintains a high acid concentration (25-28%) to improve the conversion rate, while the second-step zone moderately reduces the acid concentration (18-22%) to optimize selectivity. The sulfuric acid utilization rate is increased by more than 30%, and the acid consumption is reduced by more than 17 kg / ton caprolactam.

[0018] 2. Improved reaction efficiency: The reaction time for the first step is shortened to 5-8 minutes, and the reaction time for the second step is controlled at 10-15 minutes. The total reaction time is reduced by more than 25% compared with the traditional process.

[0019] 3. Reduced byproducts: By precisely controlling the acid concentration and temperature at each stage, the byproduct formation rate is reduced to below 3%, and the product purity is improved.

[0020] 4. Reduced energy consumption: The external circulation cooling unit works in conjunction with the acid concentration control system, reducing energy consumption by more than 30%.

[0021] 5. Enhanced safety: The intelligent metering acid addition module is equipped with an emergency shut-off valve, which isolates the acid source within 0.5 seconds when the temperature / pressure exceeds the limit, preventing runaway reactions.

[0022] 6. High control precision: The online acid concentration-flow coupling control system adopts multimodal fuzzy adaptive PID control, with acid concentration control precision reaching ±0.5% and temperature control precision reaching ±0.5℃. Attached Figure Description

[0023] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments: Appendix Figure 1 This is a schematic diagram of the process flow of the cyclohexanone oxime transposition device for zoned sulfuric acid concentration supply of the present invention. Appendix Figure 2 This is a schematic diagram of the cyclohexanone oxime transposition device for zoned sulfuric acid concentration supply according to the present invention; In the diagram: 1 - One-step displacement reactor; 11 - High acid concentration inlet; 12 - One-step reaction product outlet; 2-Two-step displacement reactor; 21-Two-step displacement reactor mixer; 22-Liquid preparation device; 3- Dual-channel external circulation output tube; 31- High concentration acid channel; 32- Low concentration acid channel; 4-Online acid concentration-flow coupling control system; 41-Refractometer; 42-Mass flow meter; 43-Multimodal fuzzy adaptive PID controller; 5-External circulation cooling unit; 51-External circulation pump; 52-External circulation cooler; 53-Bypass temperature control valve; 6-Degassing-liquid mixing unit; 61-Degassing section; 62-Liquid mixing section; 611-Shell; 612-Baffle plate; 613-Baffle plate; 7-Intelligent metering acid addition module; 71-Sulfuric acid storage tank; 72-Variable frequency metering pump; 73-Emergency shut-off valve. Detailed Implementation

[0024] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the invention.

[0025] As shown in the figure, a cyclohexanone oxime transposition process with zoned sulfuric acid concentration supply is described. In the two-step transposition process of cyclohexanone oxime preparation, this process is used to precisely control and supply sulfuric acid concentration at different stages of the transposition reaction. In this process, fuming sulfuric acid is proportionally distributed to a high-concentration acid channel and a low-concentration acid channel via an intelligent metering and acid addition module. The high-concentration acid channel is used in the first-step transposition reactor of the first-step reaction zone in the two-step transposition process, while the low-concentration acid channel is used in the second-step transposition reactor of the second-step reaction zone. The process employs a multimodal fuzzy adaptive predictive PID control algorithm, switching control modes according to the reaction stage. The first-step reaction zone uses high-precision temperature-acid concentration cascade control, while the second-step reaction zone uses byproduct prediction feedforward control.

[0026] The transposition process uses a cyclohexanone oxime transposition device with a zoned sulfuric acid concentration supply including an online acid concentration-flow coupling control system 4. The multimodal fuzzy adaptive predictive PID control algorithm is executed by the multimodal adaptive predictive PID controller 43 of the online acid concentration-flow coupling control system. The indexing process includes the following steps; Step 1: Distribute the fuming sulfuric acid to the high-concentration acid channel 31 and the low-concentration acid channel 32 in proportion through the intelligent metering acid addition module 7; Step 2: Cyclohexanone oxime enters one-step transposition reactor 1 and undergoes a Beckmann rearrangement reaction with high-concentration sulfuric acid, controlling the reaction temperature at 85-95℃ and maintaining the sulfuric acid concentration at 25-28%. Step 3: The product of the first step reaction enters the degassing-liquid mixing unit 6, where it first passes through the degassing section 61 to remove entrained gas, and then passes through the liquid mixing section 62 to be mixed with the second step circulating liquid in proportion. Step 4: The mixture enters the two-step displacement reactor 2, and the reaction temperature is controlled at 95-105℃, while the sulfuric acid concentration is adjusted to 18-22%. Step 5: Monitor and adjust the acid concentration and flow rate of each channel in real time using the online acid concentration-flow coupling control system 4; Step 6: The reaction products are cooled by the external circulation cooling unit 5 and then output. Part of the reaction products are output as the final product, and the other part is returned to the system as the second-step circulating liquid.

[0027] The execution of the multimodal fuzzy adaptive predictive PID control algorithm includes the following steps; Step S1: Multimodal switching and data acquisition; Step S2: Adjustment of fuzzy adaptive parameters; Step S3: Based on the calculation of the feedforward compensation, establish a reaction kinetics prediction model; Step S4: Incremental digital PID calculation and final control quantity synthesis; Step S5, safety interlock and parameter self-learning, specifically: if the predicted value of by-products... If the safety threshold is exceeded multiple times consecutively, or the temperature T exceeds 125℃ or the pressure P exceeds 0.5MPa, the safety procedure is triggered, and the acid source is isolated within 0.5 seconds through the emergency shut-off valve 73 of the intelligent metering acid addition module. The system uses historical operating data to fine-tune the prediction model online once a month to adapt to the slow process of catalyst activity change and ensure control accuracy.

[0028] In step S1, the controller collects system state variables in real time, including the actual value of acid concentration in the first-stage reactor. Actual acid concentration in the two-step reactor One-step reactor temperature Two-step reactor temperature and estimated rates of byproduct formation. The setpoints include the acid concentration setpoint for the one-step reactor. 25-28%, acid concentration setpoint for the two-step reactor 18-22%, Temperature Setpoint and byproduct rate safety threshold ≤3%; Calculation error signal: acid concentration error Temperature error Byproduct deviation According to the error Automatic size switching control mode: When At this time, the system is in one-step reaction mode, with the priority being to maintain a high acid concentration to improve the conversion rate; when When the system switches to a two-step reaction mode, the priority is to suppress side reactions and optimize selectivity.

[0029] In step S2, the fuzzy inference engine calculates the error... and error change rate Dynamically adjust the parameters of the PID controller The blurring process performed in step S2 specifically involves: […]. and The precise values ​​are mapped to fuzzy sets, such as {Negative Large (NB), Negative Medium (NM), Negative Small (NS), Zero (ZO), Positive Small (PS), Positive Medium (PM), Positive Large (PB)}; their membership functions adopt trigonometric functions, expressed by the formula: in, For fuzzy sets, The center point of the membership function, The width parameter; the defuzzification process in step S2 specifically involves calculating the parameter adjustment amount using the centroid method, with the following formula: in, Let i be the activation value of the i-th rule. The center value of the corresponding output fuzzy set is given by the formula: in These are the initial parameters tuned using the Ziegler-Nichols method, etc.

[0030] Step S3 includes the following: A simplified reactor state-space model was established to predict byproduct trends: in, This refers to the concentration of cyclohexanone oxime. The byproduct concentration is given by u, the control input acid pump speed or valve opening is given by k1 to k4, and the reaction rate constants are given by k1 to k4. An extended Kalman filter (EKF) is used for state estimation and prediction. in, Let be the Jacobian matrix, and Q and R be the covariance matrices of process noise and measurement noise, respectively. Predict the byproduct formation rate 15 seconds after step 3. If the predicted value exceeds the safety threshold. Then the feedforward compensation amount is generated: in, The feedforward compensation gain was experimentally tuned.

[0031] Step S4 includes the following: The feedback control quantity is calculated using an incremental digital PID algorithm. To avoid integral saturation, the formula is as follows: The final control quantity is the sum of the feedback control quantity and the feedforward compensation quantity, expressed by the formula: This control quantity The output is sent to the actuator, which includes the variable frequency metering pump 72 of the intelligent metering acid addition module and the bypass temperature control valve 53 of the external circulation cooling unit.

[0032] In step two, the one-step transposition reaction time is controlled within 5-8 minutes; in step four, the two-step transposition reaction time is controlled within 10-15 minutes. The mixing ratio in step three is precisely controlled by the proportional mixing valve in the liquid preparation section 62, and the volume ratio of the first-step reaction product to the second-step circulating liquid is 1:3-1:5.

[0033] A cyclohexanone oxime transposition device with zoned sulfuric acid concentration supply is used to operate the cyclohexanone oxime transposition process with zoned sulfuric acid concentration supply described above. The transposition device includes a one-step transposition reactor 1, a two-step transposition reactor 2, a dual-channel external circulation output pipe 3, an online acid concentration-flow coupling control system 4, an external circulation cooling unit 5, a degassing-liquid mixing unit 6, and an intelligent metering acid addition module 7. The dual-channel external circulation output pipe splits the traditional single pipe into a high-concentration acid channel and a low-concentration acid channel, which are independently connected to the one-step transposition reactor and the two-step transposition reactor, respectively, to achieve zoned supply of sulfuric acid concentration and avoid global dilution. The one-step transposition reactor 1 is equipped with a high acid concentration inlet 11 and a one-step reaction product outlet 12; The two-step shift reactor 2 is equipped with a two-step shift reactor mixer 21 and a liquid dispensing device 22; The dual-channel external circulation output pipe 3 is divided into a high-concentration acid channel 31 and a low-concentration acid channel 32, which are independently connected to the one-step shift reactor 1 and the two-step shift reactor mixer 21, respectively. The two ends of the high-concentration acid channel are connected to the high-concentration inlet of the one-step shift reactor and the liquid preparation device of the two-step shift reactor, respectively. The outlet of the first-step reaction product of the one-step displacement reactor is connected to the two-step displacement reactor via a low-concentration acid channel, an online acid concentration-flow coupling control system, and a degassing-liquid mixing unit. The online acid concentration-flow coupling control system 4 consists of a refractometer 41, a mass flow meter 42, and a multimodal fuzzy adaptive PID controller 43, which monitors and adjusts the acid concentration and flow rate in real time; it controls the acid concentration and flow rate in a closed loop to keep the acid concentration in the first step zone high to improve the conversion rate, and appropriately reduces the acid concentration in the second step zone to optimize selectivity. The online acid concentration-flow coupling control system is connected to the intelligent metering acid addition module; Installation and sampling of refractometer 41: Refractometer 41 is an online insertion type. Its sensing probe is directly installed on the circulating liquid outlet pipe of the two-step displacement reactor 2. The installation position is located before the inlet of the external circulation pump 51 to ensure the representativeness of the sampling. The probe is inserted to a depth of 1 / 3 of the pipe diameter to avoid close contact with the pipe wall in order to measure the acid concentration of the main stream. The system is set to automatically perform a sampling measurement every 5 seconds to acquire the analog signal of sulfuric acid concentration in SO3 as 4-20mA in real time, and transmit the signal to the multimodal fuzzy adaptive PID controller 43. Installation and measurement of mass flow meter 42: Mass flow meter 42 is installed on the pipeline of low concentration acid channel 32 at the rear end of the variable frequency metering pump 72 in the intelligent metering acid addition module 7. When it is working, it directly measures the mass flow rate of sulfuric acid flowing through the channel and outputs a 4-20mA analog signal to the multimodal fuzzy adaptive PID controller 43. This installation position can accurately measure the flow rate of low concentration acid that is about to enter the two-step reaction zone, providing key feedback for control.

[0034] The refractometer 41 and the mass flow meter 42, acting as the "sensors" of the system, continuously transmit the real-time monitored acid concentration and flow signals to the analog input AI module of the multimodal fuzzy adaptive PID controller 43 via shielded signal cables. The multimodal fuzzy adaptive PID controller 43 compares the received signal with the internally set target value, such as the two-step reactor acid concentration set value c2,sp=20%, and generates an error signal e(t). The error signal e(t) and its rate of change ec(t) are the direct inputs to the control algorithms in steps S1 and S2; the specific connection logic is as follows: The multimodal fuzzy adaptive PID controller 43 first executes the multimodal switching and data acquisition in step S1, compares the received c2(t) with c2 and sp, and determines whether the system is in a one-step or two-step reaction mode. Subsequently, in step S2. Fuzzy adaptive parameter adjustment, the PID parameters Kp, Ki, and Kd are dynamically tuned using e(t) and ec(t); Finally, based on the calculation results, the multimodal fuzzy adaptive controller 43 sends a control signal, such as 4-20mA, to the variable frequency metering pump 72 through its analog output, instructing it to adjust its speed, thereby changing the amount of sulfuric acid added, and realizing a complete closed-loop control of "monitoring-calculation-adjustment".

[0035] The external circulation cooling unit 5 consists of an external circulation pump 51, an external circulation cooler 52, and a bypass temperature control valve 53; it is used for constant temperature and coordinated acid concentration control. The two-step rotation reactor is connected to the external circulation cooling unit; The degassing-liquid mixing unit 6 includes a degassing section 61 and a liquid mixing section 62. The degassing section 61 is equipped with a gas separation device, and the liquid mixing section 62 is equipped with a proportional mixing valve. When the transposition device is working, the first step product of the cyclohexanone oxime transposition process is first degassed by the degassing-liquid mixing unit to remove entrained gas, and then mixed with the second step circulating liquid in proportion in the liquid mixing section of the degassing-liquid mixing unit to prevent a sudden drop in acid concentration. The intelligent metering and acid addition module 7 includes a sulfuric acid storage tank 71, a variable frequency metering pump 72, and an emergency shut-off valve 73, which are used to receive instructions from the control system to achieve accurate metering and emergency isolation of sulfuric acid; The opening of the liquid preparation device 22 faces upward, and its upper part is a trumpet-shaped tube with a diameter that decreases from top to bottom. The lower part is a cylindrical tube that smoothly transitions to the upper part. The degassing section 61 includes a housing 611, a guide plate 612, and a baffle plate 613. The guide plate is fixed to the top of the housing, with one side being the exhaust zone and the other side being the guide zone. The volume of the exhaust zone is larger than the volume of the guide zone.

[0036] Example 1: The cyclohexanone oxime transposition device with zoned sulfuric acid concentration supply is implemented as follows: The one-step transposition reactor is made of 316L stainless steel, with a volume of 2 m³, and is equipped with a high-acid concentration inlet and a one-step reaction product outlet. An internal stirring device with a rotation speed of 100-200 rpm is installed. The two-step transposition reactor has a volume of 5 m³ and contains a two-step transposition reactor mixer and a liquid distribution device. The liquid distribution device is located at the bottom of the reactor, with its opening facing upwards. The upper part is a funnel-shaped tube with a diameter decreasing from 500 mm to 300 mm, and the lower part is a cylindrical tube with a diameter of 300 mm. The dual-channel external circulation output pipe is divided into a high-concentration acid channel and a low-concentration acid channel, with diameters of 100 mm and 150 mm respectively, both made of Hastelloy C276 material, resistant to concentrated sulfuric acid corrosion. The multimodal fuzzy adaptive PID controller (43) operates according to the following logic, and its control process is closely coupled with the process steps: The controller (43) continuously receives real-time acid concentration signals from the refractometer (41) and flow signals from the mass flow meter (42). First, the controller performs multimodal switching and data acquisition (corresponding to step S1 of claim 4): it acquires the actual acid concentration values ​​of the two-step reactor. With set value (20%) were compared, and the error was calculated. If the error If the system is in a one-step reaction mode, the control objective is to prioritize maintaining a high acid concentration to maximize the conversion rate; if the error... Then, the system switches to a two-step reaction mode, with the control objective shifting to prioritizing the suppression of side reactions to optimize selectivity. Subsequently, the controller performs fuzzy adaptive parameter adjustment (corresponding to step S2 of claim 4): based on the aforementioned error e(t) and its rate of change. The proportional (Kp), integral (Ki), and derivative (Kd) parameters of the PID controller are dynamically adjusted via a built-in fuzzy inference engine. For example, when the system is in a two-step reaction mode and detects a low acid concentration (negative error) that continues to decrease (negative rate of change), the fuzzy rule base will output instructions to appropriately enhance the proportional and integral actions of the controller to increase the acid concentration to the set value more quickly. Then, the controller performs incremental digital PID calculations (corresponding to step S4 of claim 4), based on the adaptively adjusted parameters. The reference control quantity for adjusting the speed of the variable frequency metering pump (72) is calculated. Specifically, when the system is in a two-step reaction mode, the controller activates a reaction kinetic prediction model for feedforward compensation (corresponding to step S3 of claim 4): this model predicts the byproduct generation rate over the next 10-15 seconds based on the real-time state. If the predicted value exceeds the safety threshold, a feedforward compensation amount is generated. This compensation will proactively suppress the formation of byproducts by increasing the opening of the cooling water valve or fine-tuning the acid pump speed in advance. The final control quantity u(k) is the baseline control quantity. With feedforward compensation The sum of these steps. Through the above steps, the controller (43) achieves precise and adaptive control of the sulfuric acid concentration, ensuring that the entire transposition process can operate in the optimal state at each stage.

[0037] Example 2: Specific Implementation of Online Acid Concentration-Flow Coupling Control System This embodiment focuses on the specific installation, signal flow and connection with the core algorithm of the online acid concentration-flow coupling control system (4). 1. Installation and Use of Sampling Equipment: Installation and Sampling of Refractometer (41): The refractometer (41) is an online insertion type. Its sensing probe is directly installed on the circulating liquid outlet pipe of the two-step rotary reactor (2). The installation position is located before the inlet of the external circulation pump (51) to ensure the representativeness of the sampling. The probe is inserted to a depth of 1 / 3 of the pipe diameter to avoid close contact with the pipe wall to measure the acid concentration of the main stream. The system is set to automatically perform sampling measurement every 5 seconds to obtain the analog signal (4-20mA) of sulfuric acid concentration (calculated as SO3) in real time and transmit the signal to the multimodal fuzzy adaptive PID controller (43). Installation and Measurement of Mass Flow Meter (42): The mass flow meter (42) is installed on the pipeline of the low concentration acid channel (32) at the rear end of the frequency conversion metering pump (72) in the intelligent metering acid addition module (7). When it is working, it directly measures the mass flow rate of sulfuric acid flowing through the channel and outputs a 4-20mA analog signal to the controller (43). This installation position can accurately measure the flow rate of low-concentration acid that is about to enter the two-step reaction zone, providing key feedback for control. 2. Signal flow and closed-loop control formation: As mentioned above, the refractometer (41) and mass flow meter (42) act as the "sensors" of the system, continuously transmitting the real-time monitored acid concentration and flow rate signals to the analog input (AI) module of the PID controller (43) through shielded signal cables. The controller (43) compares the received signal with the internally set target value (such as the two-step reactor acid concentration set value c2,sp=20%) and generates an error signal e(t). 3. Connection with multimodal fuzzy adaptive PID control algorithm: This error signal e(t) and its rate of change ec(t) are the direct inputs of the control algorithm (steps S1 and S2) described in claim 4. The specific connection logic is as follows: The controller (43) first executes S1. Multimodal switching and data acquisition, compares the received c2(t) with c2,sp, and determines whether the system is in a one-step or two-step reaction mode. Subsequently, in S2. Fuzzy adaptive parameter adjustment, the PID parameters (Kp, Ki, Kd) are dynamically tuned using e(t) and ec(t). Finally, the controller (43) sends a control signal (such as 4-20mA) to the variable frequency metering pump (72) through its analog output based on the calculation results, instructing it to adjust its speed, thereby changing the amount of sulfuric acid added, and realizing the complete closed-loop control of "monitoring-calculation-adjustment". Through the supplement of the above specific implementation method, the installation position of the sampling equipment, the sampling method and how the signal is used as the algorithm input are clarified, and finally the control command drives the actuator, which completely describes the implementation path of acid concentration-flow closed-loop control.

[0038] Example 3: The process of cyclohexanone oxime transposition using the above-described apparatus with zoned sulfuric acid concentration supply is carried out according to the following steps: (1) Fuming sulfuric acid (containing 20% ​​SO3) is distributed to the high-concentration acid channel and the low-concentration acid channel in a ratio of 7:3 through the intelligent metering acid addition module.

[0039] (2) Cyclohexanone oxime (30wt% cyclohexane solution) was introduced into a one-step transposition reactor at a flow rate of 2m³ / h to carry out the Beckmann rearrangement reaction with high concentration sulfuric acid. The reaction temperature was controlled at 90±0.5℃, the sulfuric acid concentration was maintained at 26±0.5%, and the reaction time was 6 minutes.

[0040] (3) The product of the first step reaction enters the degassing-liquid mixing unit. First, the SO2 and other gases entrained in the degassing section are removed, and then the product is mixed with the second step circulating liquid in the liquid mixing section at a volume ratio of 1:4.

[0041] (4) The mixture enters the two-step displacement reactor, the reaction temperature is controlled at 100±0.5℃, the sulfuric acid concentration is adjusted to 20±0.5%, and the reaction time is 12 minutes.

[0042] (5) The acid concentration and flow rate of each channel are monitored and adjusted in real time through the online acid concentration-flow coupling control system. The refractometer collects acid concentration data every 5 seconds, the mass flow meter monitors the flow rate in real time, and the PID controller dynamically adjusts the speed of the variable frequency metering pump and the valve opening according to the deviation between the set value and the measured value.

[0043] (6) The reaction products are cooled to 50°C by the external circulation cooling unit and then output.

[0044] Example 4: A cyclohexanone oxime transposition device with zoned sulfuric acid concentration supply includes a one-step transposition reactor, a two-step transposition reactor, a dual-channel external circulation output pipe, an online acid concentration-flow coupling control system, an external circulation cooling unit, a degassing-liquid mixing unit, and an intelligent metering acid addition module.

[0045] The one-step transposition reactor is equipped with a high acid concentration inlet and a one-step reaction product outlet, and is used for the initial reaction of cyclohexanone oxime with high concentration sulfuric acid.

[0046] The two-step shift reactor is equipped with a two-step shift reactor mixer and a liquid distribution device for the second step reaction and liquid distribution.

[0047] The dual-channel external circulation output pipe splits the traditional single pipe into a high-concentration acid channel and a low-concentration acid channel, which are independently connected to the one-step reaction zone and the two-step mixer, respectively, to achieve zoned supply of sulfuric acid concentration and avoid global dilution.

[0048] The online acid concentration-flow coupling control system consists of a refractometer, a mass flow meter, and a multimodal fuzzy adaptive PID controller. The refractometer monitors the acid concentration in real time, the mass flow meter measures the sulfuric acid flow, and the PID controller dynamically adjusts the dual-channel flow based on the deviation between the set value and the measured value, forming a closed-loop control of acid concentration-flow.

[0049] The external circulation cooling unit consists of an external circulation pump, an external circulation cooler, and a bypass temperature control valve. It is used to maintain a stable reaction temperature and works in conjunction with the acid concentration control system.

[0050] The degassing-liquid mixing unit includes a degassing section and a liquid mixing section. The degassing section is equipped with a gas separation device to remove the gas entrained in the first-step product. The liquid mixing section is equipped with a proportional mixing valve to mix the first-step product and the second-step circulating liquid in proportion to prevent a sudden drop in acid concentration.

[0051] The intelligent metering and acid addition module includes a sulfuric acid storage tank, a variable frequency metering pump, and an emergency shut-off valve. It receives instructions from the online acid concentration-flow coupling control system to achieve accurate metering and emergency isolation of sulfuric acid.

[0052] Furthermore, the liquid mixing device has an upward-facing opening, with an upper part that is a trumpet-shaped tube whose diameter decreases from top to bottom, and a lower part that is a cylindrical tube that smoothly transitions to the upper part. This design facilitates smooth liquid flow and mixing.

[0053] Furthermore, the degassing section includes a shell, a guide plate, and a baffle plate. The guide plate is fixed to the top of the shell, with one side being the exhaust zone and the other side being the guide zone. The volume of the exhaust zone is larger than the volume of the guide zone. This structure is beneficial for gas separation.

[0054] Furthermore, the online acid concentration-flow coupling control system adopts a multimodal fuzzy adaptive PID controller, which can automatically switch the control mode according to the reaction stage. The first-step reaction zone adopts high-precision temperature-acid concentration cascade control, and the second-step reaction zone adopts by-product prediction feedforward control.

[0055] The process of supplying cyclohexanone oxime translocation with zoned sulfuric acid concentration using the above-described apparatus includes the following steps: (1) Fuming sulfuric acid is distributed proportionally to the high-concentration acid channel and the low-concentration acid channel through the intelligent metering acid addition module; (2) Cyclohexanone oxime enters a one-step transposition reactor and undergoes a Beckmann rearrangement reaction with high-concentration sulfuric acid, with the reaction temperature controlled at 85-95℃ and the sulfuric acid concentration maintained at 25-28%; (3) The product of the first step reaction enters the degassing-liquid mixing unit, where it first passes through the degassing section to remove entrained gas, and then passes through the liquid mixing section to be mixed with the second step circulating liquid in proportion. (4) The mixture enters the two-step displacement reactor, and the reaction temperature is controlled at 95-105℃, and the sulfuric acid concentration is adjusted to 18-22%; (5) The acid concentration and flow rate of each channel are monitored and adjusted in real time through an online acid concentration-flow coupling control system; (6) The reaction products are output after being cooled by the external circulation cooling unit.

[0056] Furthermore, the one-step transposition reaction time in step (2) is controlled at 5-8 minutes, and the two-step transposition reaction time in step (4) is controlled at 10-15 minutes.

[0057] Furthermore, the mixing ratio in step (3) is precisely controlled by the proportional mixing valve in the liquid preparation section, and the volume ratio of the first-step reaction product to the second-step circulating liquid is 1:3-1:5.

[0058] Furthermore, the process employs a multimodal fuzzy adaptive predictive PID control algorithm, switching the control mode according to the reaction stage. The first-step reaction zone uses high-precision temperature-acid concentration cascade control, while the second-step reaction zone uses by-product prediction feedforward control.

[0059] The online acid concentration-flow coupling control system adopts multimodal fuzzy adaptive PID control, and the specific implementation method is as follows: a. Fuzzy adaptive parameter adjustment The fuzzy inference engine dynamically adjusts the PID parameters based on the error e(t) and the rate of change of error ec(t). in Output from fuzzy inference engine. The two-step reaction zone adopts a byproduct prediction feedforward control mode: b. Reaction kinetic prediction model Establish a simplified state-space model of the reactor: Where x1 is the concentration of cyclohexanone oxime, x2 is the concentration of byproducts, and u is the control input.

[0060] c. Incremental PID control and feedforward compensation Incremental PID calculation of feedback control quantity: Calculation of feedforward compensation: Final control quantity synthesis: Through the above control strategies, the system can achieve an acid concentration control accuracy of ±0.5% in the first-step zone, ±0.3% in the second-step zone, and a temperature control accuracy of ±0.5℃.

Claims

1. A process for the transposition of cyclohexanone oxime in which the concentration of sulfuric acid is supplied in zones, characterized in that: The transposition process is used for partition supply and accurate control of sulfuric acid concentration in different stages of transposition reaction in the two-step transposition process of cyclohexanone oxime preparation process. In the transposition process, fuming sulfuric acid is proportionally distributed to a high-concentration acid channel and a low-concentration acid channel through an intelligent metering acid adding module. The high-concentration acid channel is used for a one-step transposition reactor in a one-step reaction zone of the two-step transposition process, and the low-concentration acid channel is used for a two-step transposition reactor in a two-step reaction zone of the two-step transposition process. In the transposition process, a multi-modal fuzzy adaptive predictive PID control algorithm is adopted, and the control mode is switched according to the reaction stage. The one-step reaction zone adopts high-precision temperature-acid concentration cascade control, and the two-step reaction zone adopts by-product predictive feedforward control.

2. A process for the transposition of cyclohexanone oxime in a zoned sulfuric acid concentration feed according to claim 1, characterized in that: The transposition process uses a cyclohexanone oxime transposition device including a partition sulfuric acid concentration supply system of an online acid concentration-flow coupling regulation system (4), and a multi-modal fuzzy adaptive predictive PID control algorithm is executed by a multi-modal adaptive predictive PID controller (43) of the online acid concentration-flow coupling regulation system; The transposition process includes the following steps: Step one, fuming sulfuric acid is proportionally distributed to a high-concentration acid channel (31) and a low-concentration acid channel (32) through an intelligent metering acid adding module (7); Step two, cyclohexanone oxime enters a one-step transposition reactor (1) to perform a Beckmann rearrangement reaction with high-concentration sulfuric acid, the reaction temperature is controlled to be 85-95 DEG C, and the sulfuric acid concentration is maintained to be 25-28%; Step three, the one-step reaction product enters a degassing-liquid preparation combined device (6), first passes through a degassing section (61) to remove entrained gas, and then passes through a liquid preparation section (62) to be mixed with two-step circulating liquid in proportion; Step four, the mixed liquid enters a two-step transposition reactor (2), the reaction temperature is controlled to be 95-105 DEG C, and the sulfuric acid concentration is adjusted to be 18-22%; Step five, the acid concentration and flow rate of each channel are monitored and adjusted in real time through an online acid concentration-flow coupling regulation system (4); Step six, the reaction product is cooled through an external circulation cooling unit (5) and then output.

3. A process for the transposition of cyclohexanone oxime in a zoned sulfuric acid concentration feed according to claim 2, characterized in that: The execution of the multi-modal fuzzy adaptive predictive PID control algorithm includes the following steps: Step S1, multi-modal switching and data acquisition; Step S2, fuzzy adaptive parameter adjustment; Step S3, based on feedforward compensation amount calculation, a reaction kinetics prediction model is established; Step S4, incremental digital PID calculation and final control amount synthesis; Step S5, safety interlock and parameter self-learning, specifically: if the byproduct predicted value If the safety threshold is exceeded continuously for multiple times, or the temperature T exceeds 125℃ and the pressure P exceeds 0.5MPa, the safety procedure is triggered, the acid source is isolated by the emergency shut-off valve (73) of the intelligent metering acid module; the system fine-tunes the prediction model using historical operation data to adapt to the slow process of catalyst activity change, and ensures the control precision.

4. A process for the cyclohexanone oxime transposition with zoned sulfuric acid concentration feed according to claim 3, characterized in that: In step S1, the controller collects system state variables in real time, including the actual value of the acid concentration in the one-step reactor , the actual value of the acid concentration in the two-step reactor , the temperature of the one-step reactor , the temperature of the two-step reactor , and the estimated value of the byproduct generation rate ; the set values include the set value of the acid concentration in the one-step reactor (25-28%), the set value of the acid concentration in the two-step reactor (18-22%), the temperature set value , and the byproduct rate safety threshold (≤3%); the calculation error signals include the acid concentration error , the temperature error , and the byproduct deviation ; the control mode is automatically switched according to the size of the error : when , the system is in the one-step reaction mode, and the priority is to maintain a high acid concentration to improve the conversion rate; when , the system switches to the two-step reaction mode, and the priority is to suppress side reactions and optimize selectivity.

5. A process for the transposition of cyclohexanone oxime in a zoned sulfuric acid concentration feed according to claim 3, characterized in that: In step S2, the fuzzy inference engine calculates the error... and error change rate Dynamically adjust the parameters of the PID controller The blurring process performed in step S2 specifically involves: […]. and The precise values ​​are mapped to fuzzy sets, such as {Negative Large (NB), Negative Medium (NM), Negative Small (NS), Zero (ZO), Positive Small (PS), Positive Medium (PM), Positive Large (PB)}; their membership functions adopt trigonometric functions, expressed by the formula: wherein, is a fuzzy set, is a center point of membership function, is a width parameter; the defuzzification process in step S2 is specifically: using the barycentric method to calculate the parameter adjustment amount, and the calculation formula is: wherein, is the activation degree of the ith rule, is the center value of the corresponding output fuzzy set; the final adaptive PID parameter is expressed in the formula as: wherein is the initial parameter of the Ziegler-Nichols method or the like.

6. A process for the cyclohexanone oxime transposition with zoned sulfuric acid concentration feed according to claim 3, characterized in that: In step S3, the following contents are included: A simplified reactor state space model was established to predict by-product trends: where, is cyclohexanone oxime concentration, is by-product concentration, u is control input, and k1 to k4 are reaction rate constants; Extended Kalman Filter (EKF) was used for state estimation and prediction: where, is the Jacobian matrix, Q and R are process noise and measurement noise covariance matrices; Predicting future by-product generation rates of step 3 ; If the predicted value exceeds a safety threshold then a feedforward compensation is generated: wherein is a feedforward compensation gain.

7. A process for the transposition of cyclohexanone oxime in a zoned sulfuric acid concentration feed according to claim 3, characterized in that: In step S4, the following contents are included: An incremental digital PID algorithm is used to calculate the feedback control variable , and integral saturation is avoided, which is expressed by the formula as follows: The final control variable is the sum of the feedback control variable and the feedforward compensation variable, which is expressed by the formula as follows: The control variable is output to the actuator, which includes a variable frequency metering pump (72) of the intelligent metering acid adding module and a bypass temperature control valve (53) of the external circulation cooling unit.

8. A process for the transposition of cyclohexanone oxime in a zoned sulfuric acid concentration feed according to claim 2, characterized in that: In step two, the one-step transposition reaction time is controlled to be within 5-8 minutes, and in step four, the two-step transposition reaction time is controlled to be within 10-15 minutes; The mixing ratio in step three is accurately controlled through a proportional mixing valve of the liquid preparation section (62), and the volume ratio of the one-step reaction product to the two-step circulating liquid is 1:3-1:

5.

9. A zoned sulfuric acid concentration fed cyclohexanone oxime transposition apparatus for operating a zoned sulfuric acid concentration fed cyclohexanone oxime transposition process according to claim 2, characterized by: The transposition device includes a one-step transposition reactor (1), a two-step transposition reactor (2), a double-channel external circulation output pipe (3), an online acid concentration-flow coupling regulation system (4), an external circulation cooling unit (5), a degassing-liquid preparation combined device (6), and an intelligent metering acid adding module (7); The one-step transposition reactor (1) is provided with a high-acid-concentration inlet and a one-step reaction product outlet; The two-step transposition reactor (2) is internally provided with a two-step transposition reactor mixer (21) and a liquid preparation device (22); The double-channel external circulation output pipe (3) is divided into a high-concentration acid channel (31) and a low-concentration acid channel (32), and is independently connected with the one-step transposition reactor (1) and the two-step transposition reactor mixer (21), respectively; The online acid concentration-flow coupling regulation system (4) is composed of a refractometer (41), a mass flowmeter (42) and a multimode fuzzy self-adaptive PID controller (43), and is used for real-time monitoring and adjusting the acid concentration and flow; The sensing probe of the refractometer (41) is directly installed on the circulating liquid outlet pipeline of the two-step transposition reactor (2), and is installed at a position before the inlet of the external circulation pump (51), so as to obtain a simulated signal of the sulfuric acid concentration in real time, and transmit the signal to the multimode fuzzy self-adaptive PID controller (43); The mass flowmeter (42) is installed at the rear end of the variable-frequency metering pump (72) in the intelligent metering acid adding module (7), and is installed on the pipeline of the low-concentration acid channel (32), so that the mass flow of the sulfuric acid flowing through the channel is directly measured during the operation of the mass flowmeter (42), and a simulated signal is output to the multimode fuzzy self-adaptive PID controller (43); The refractometer (41) and the mass flowmeter (42) continuously transmit the real-time monitored acid concentration and flow signals to the multimode fuzzy self-adaptive PID controller (43) through a shielded signal cable; the multimode fuzzy self-adaptive PID controller (43) compares the received signals with the internally set target values, and generates an error signal e(t) based on the target values, wherein the target values include a two-step reactor acid concentration set value c2; The error signal e(t) and its change rate ec(t) are direct input quantities of the control algorithms of steps S1 and S2; the specific connection logic is as follows: The multimode fuzzy self-adaptive PID controller (43) first performs multimode switching and data acquisition of step S1, compares the received c2(t) with c2 and sp, and judges whether the system is in one-step or two-step reaction mode; Then, in the fuzzy self-adaptive parameter adjustment of step S2, the PID parameters (Kp, Ki, Kd) are dynamically adjusted based on e(t) and ec(t); Finally, the multimode fuzzy self-adaptive controller (43) sends a control signal (such as 4-20 mA) to the variable-frequency metering pump (72) through its analog output based on the operation result, instructs the variable-frequency metering pump (72) to adjust the rotating speed, thereby changing the sulfuric acid adding amount, and realizes complete closed-loop control of "monitoring-computing-adjusting".

10. A cyclohexanone oxime transposition apparatus with zoned sulfuric acid concentration feed according to claim 9, characterized in that: The external circulation cooling unit (5) is composed of an external circulation pump (51), an external circulation cooler (52) and a bypass temperature regulating valve (53); The degassing-liquid preparation combination device (6) comprises a degassing section (61) and a liquid preparation section (62), the degassing section (61) is provided with a gas separation device, and the liquid preparation section (62) is provided with a proportional mixing valve; During the operation of the transposition device, the one-step product of the cyclohexanone oxime transposition process is first degassed to remove entrained gas in the degassing-liquid preparation combination device, and then is proportionally mixed with the two-step circulating liquid in the liquid preparation section of the degassing-liquid preparation combination device, so as to prevent the acid concentration from suddenly decreasing; The intelligent metering acid adding module (7) comprises a sulfuric acid storage tank (71), a variable frequency metering pump (72) and an emergency cut-off valve (73), and is used for accepting a regulation system instruction to realize accurate metering and emergency isolation of sulfuric acid; The opening of the liquid preparation device (22) faces upwards, the upper part is a horn-shaped tube body, the diameter decreases along the direction from top to bottom, and the lower part is a cylindrical tube body which is connected to the upper part in a smooth transition manner; The degassing section (61) comprises a shell (611), a flow guide plate (612) and a baffle (613). The flow guide plate is fixed at the top of the shell, one side of the flow guide plate is an exhaust area, and the other side is a flow guide area. The volume of the exhaust area is greater than the volume of the flow guide area.

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