Ethoxylation reaction stage temperature optimization control method, device, equipment and readable storage medium

Abstract

The application relates to an ethoxylation reaction stage temperature optimization control method, device, equipment and readable storage medium. The method comprises the following steps: obtaining an ethylene oxide feed flow cumulative amount as a reaction progress judgment benchmark; dividing multiple reaction stages according to the cumulative amount, and presetting a control parameter group for each stage; calculating the cumulative amount in real time, automatically switching the stage when a preset threshold is reached and a precondition is met, and the parameter group of each stage is executed only once; performing cascade control of the kettle bottom temperature and the feed flow according to a feed flow benchmark value to actively adjust the reaction heat release; and automatically switching a heat conduction oil control strategy without disturbance according to a heat conduction oil control mode. The method realizes self-adaptive control of ethoxylation reaction in stages, actively controls temperature from the source, overcomes the hysteresis of traditional passive heat removal, and improves temperature control precision and production safety. Moreover, the method is also suitable for strong exothermic and staged batch reaction processes of propoxylation or polyesterification.

Description

Technical Field

[0001] This application relates to the field of chemical automation technology, and in particular to a method, apparatus, equipment, and readable storage medium for optimizing temperature control during the ethoxylation reaction stage. Background Technology

[0002] Ethoxylation is the ring-opening addition reaction of ethylene oxide (EO) with compounds containing active hydrogen (such as alcohols, phenols, and amines) under the action of a catalyst. The product is a nonionic surfactant, widely used in the textile, paper, coating, pharmaceutical, and daily chemical industries. This reaction exhibits significant exothermic characteristics, with a reaction heat as high as approximately 92–100 kJ / molEO. Furthermore, the reaction rate is strongly coupled with temperature; increasing the temperature accelerates the reaction, generating even more heat and creating a positive feedback effect, posing a risk of thermal runaway. In addition, the reaction process exhibits a nonlinear progression: the exothermic reaction is weak in the initial stage, intense in the middle stage, and gradually weakens in the later stage, showing distinct stage characteristics.

[0003] Currently, the control strategy for the reaction stage of ethoxylation units is relatively simple, mainly relying on manual operator control of the ethylene oxide feed flow rate and the opening of the heat transfer oil heating / cooling valves. Specifically, the ethylene oxide feed uses a three-PID low-selection control (single-loop PID for feed flow rate, single-loop PID for reactor bottom temperature, and single-loop PID for reactor pressure), while the heat transfer oil uses dual-temperature cascade PID split-range control. However, in actual operation, operators often increase the ethylene oxide feed rate before the reaction stabilizes in order to shorten the reaction time. The significant lag in heat transfer oil cooling leads to drastic temperature fluctuations and even "runaway" phenomena, which in severe cases trigger interlock shutdowns, thus prolonging the reaction time. Furthermore, when catalyst activity fluctuates or raw material quality changes, the fixed feed rate does not match the actual reaction requirements, further exacerbating the difficulty of temperature control. Existing technologies lack the ability to adaptively differentiate between reaction stages and cannot automatically adjust the control strategy according to the reaction progress, resulting in low temperature control accuracy, high reliance on manual intervention, and large batch-to-batch variations in product quality.

[0004] Therefore, there is an urgent need for a temperature optimization control method that can automatically adjust control parameters in stages according to the reaction progress and actively regulate the heat release from the source rather than passively relying on the cooling system, in order to solve the problems of control lag, large temperature fluctuations and excessive manual intervention in the existing technology. Summary of the Invention

[0005] Therefore, it is necessary to provide a method, apparatus, equipment, and readable storage medium for optimizing the temperature control of the ethoxylation reaction stage, which can achieve full-process automation, staged adaptive high-precision temperature control, significantly suppress temperature fluctuations, shorten the reaction cycle, reduce operational risks and human intervention, and ensure product quality stability, in response to the above-mentioned technical problems.

[0006] In a first aspect, this application provides a method for optimizing and controlling the temperature during the ethoxylation reaction stage, including: The method includes: The cumulative ethylene oxide feed flow rate is obtained, and the cumulative ethylene oxide feed flow rate is used as the benchmark for judging the reaction progress. Based on the cumulative ethylene oxide feed flow rate, the ethoxylation reaction process is divided into multiple reaction stages, and a corresponding set of control parameters is preset for each reaction stage. The set of control parameters includes: heat transfer oil control mode, reactor bottom temperature set value, ethylene oxide feed flow rate reference value, and heating rate or cooling rate. During the reaction, the cumulative amount of ethylene oxide feed flow is calculated in real time. When the cumulative amount reaches the preset threshold corresponding to the current reaction stage and the preconditions are met, the system automatically switches to the next reaction stage and loads the control parameter group corresponding to that stage. The control parameter group of each stage is executed only once after the preconditions are met. Based on the ethylene oxide feed flow rate reference value in the loaded control parameter group, cascade control of the reactor bottom temperature and ethylene oxide feed flow rate is performed to actively adjust the heat release of the reaction; and based on the heat transfer oil control mode in the loaded control parameter group, the control strategy of the heat transfer oil is automatically and seamlessly switched to meet the heat removal or heating requirements. The method is also applicable to strongly exothermic, staged batch reaction processes of propoxylation or polyesterification.

[0007] In one embodiment, the cascade control of the reactor bottom temperature and the ethylene oxide feed flow rate includes: The reactor bottom temperature PID controller is used as the main loop, and the ethylene oxide feed flow PID controller is used as the secondary loop. The main circuit outputs a flow correction coefficient based on the deviation between the current bottom temperature and the set value, and the secondary circuit adjusts the opening of the ethylene oxide feed valve based on the flow correction coefficient and the adjusted flow set value. Furthermore, the reactor temperature and reactor pressure protection logic in the three-PID low-selection control of ethylene oxide feed is retained, and the feed valve is closed preferentially under high temperature or high pressure conditions.

[0008] In one embodiment, the heat transfer oil control mode includes at least one of the following: Mode 1: Dual-temperature cascade PID split-range control, with the main loop being the heat exchanger outlet material temperature and the secondary loop being the heat transfer oil outlet oil temperature; Mode 2: Based on Mode 1, the temperature setpoint increases from the starting value to the target value, and the rate of increase is determined by the heating rate or cooling rate parameter. Mode 3: Single-loop PID split-range control of heat exchanger outlet material temperature; Mode 4: Based on Mode 3, the temperature setpoint increases from the starting value to the target value, and the rate of increase is determined by the heating rate or cooling rate parameter. Mode 5: Single-loop PID split-range control of heat transfer oil outlet temperature; Mode 6: Single-loop PID control of heat exchanger outlet material temperature, quantitative opening of hot oil valve, and PID control of cold oil valve; Mode 7: Single-loop PID control of heat exchanger outlet material temperature, hot oil valve fully closed, PID control of cold oil valve; Among them, seamless switching between different modes is supported.

[0009] In one embodiment, the control strategy of automatically and seamlessly switching the heat transfer oil control mode according to the loaded control parameter group includes: During the preheating stage, switch to mode two or mode four and heat to the reaction initiation temperature at the rate set by the heating rate or cooling rate parameter. In the initial stage of the reaction, first switch to mode five to establish the temperature reference of the heat transfer oil, and then switch to mode one to fine-tune the material temperature; During the middle of the reaction, switch to mode six, fix the opening of the hot oil valve, and use PID control to remove heat from the cold oil valve; In the later stages of the reaction, switch to mode one or mode three to smoothly transition to a state of heating and cooling equilibrium. During the ripening stage, switch to mode six to maintain a constant temperature; During the cooling phase, switch to mode seven, fully close the hot oil valve, and use PID control to cool the cold oil valve at the rate set by the heating rate or cooling rate parameter.

[0010] In one embodiment, the plurality of reaction stages include at least: a preheating stage, an initial reaction stage, a middle reaction stage, a later reaction stage, a ripening stage, and a cooling stage; Specifically, during the preheating and initial reaction stages, ethylene oxide feed flow control is disabled or set to a low flow reference value; during the initial, middle, and later stages of the reaction, the cascade control is automatically activated; and during the maturation and cooling stages, the ethylene oxide feed valve is closed, and feed flow control is disabled.

[0011] Secondly, this application also provides a temperature optimization and control device for the ethoxylation reaction stage, the device comprising: The reaction progress judgment module is used to obtain the cumulative amount of ethylene oxide feed flow rate and use the cumulative amount of ethylene oxide feed flow rate as the reaction progress judgment benchmark. The stage division and parameter preset module is used to divide the ethoxylation reaction process into multiple reaction stages based on the cumulative ethylene oxide feed flow rate, and preset a corresponding set of control parameters for each reaction stage. The set of control parameters includes: heat transfer oil control mode, reactor bottom temperature set value, ethylene oxide feed flow rate reference value, and heating rate or cooling rate. The automatic stage switching module is used to calculate the cumulative amount of ethylene oxide feed flow in real time during the reaction process. When the cumulative amount reaches the preset threshold corresponding to the current reaction stage and the preconditions are met, it automatically switches to the next reaction stage and loads the control parameter group corresponding to the stage. The control parameter group of each stage is executed only once after the preconditions are met. A temperature-flow cascade control module is used to perform cascade control of the reactor bottom temperature and ethylene oxide feed flow rate based on the ethylene oxide feed flow rate reference value in the loaded control parameter group, so as to actively adjust the heat of reaction; and The heat transfer oil multi-mode control module is used to automatically and seamlessly switch the control strategy of the heat transfer oil according to the heat transfer oil control mode in the loaded control parameter group, so as to meet the heat removal or heating requirements. The device is also suitable for strongly exothermic, staged batch reaction processes of propoxylation or polyesterification.

[0012] In one embodiment, the temperature-flow cascade control module is specifically used for: The reactor bottom temperature PID controller is used as the main loop, and the ethylene oxide feed flow PID controller is used as the secondary loop. The main circuit outputs a flow correction coefficient based on the deviation between the current bottom temperature and the set value, and the secondary circuit adjusts the opening of the ethylene oxide feed valve based on the flow correction coefficient and the adjusted flow set value.

[0013] In one embodiment, the device further includes a safety protection module for retaining the reactor temperature and reactor pressure protection logic in the three-PID low-select control of ethylene oxide feed, and prioritizing the shutdown of the feed valve under high temperature or high pressure conditions.

[0014] In one embodiment, the heat transfer oil multi-mode control module is specifically used to support switching between the following seven modes: Mode 1: Dual-temperature cascade PID split-range control; Mode 2: Dual-temperature cascade PID split-range control with ramp function, the ramp rate is determined by the heating rate or cooling rate parameter; Mode 3: Single-loop PID split-range control of heat exchanger outlet material temperature; Mode 4: Single-loop PID split-range control of the outlet material temperature of the heat exchanger with ramp function, the ramp rate is determined by the heating rate or cooling rate parameter; Mode 5: Single-loop PID split-range control of heat transfer oil outlet temperature; Mode 6: Single-loop PID control of heat exchanger outlet material temperature, with hot oil valve quantitative control; Mode 7: Single-loop PID control of heat exchanger outlet material temperature, with hot oil valve fully closed.

[0015] Thirdly, this application also provides a computer device, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps of the method described in any of the embodiments of the first aspect.

[0016] Fourthly, this application also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the method described in any of the embodiments of the first aspect.

[0017] Fifthly, this application also provides a computer program product, including a computer program that, when executed by a processor, implements the steps of the method described in any of the embodiments of the first aspect.

[0018] The aforementioned method, apparatus, computer equipment, computer-readable storage medium, and computer program product for optimizing temperature control during the ethoxylation reaction stage use the cumulative ethylene oxide feed flow rate as a benchmark for judging the reaction progress. Compared to relying on manual experience, this achieves objective quantification of the reaction process and batch-to-batch consistency, avoiding subjective misjudgment. Furthermore, it divides the reaction into multiple stages based on the cumulative flow rate and presets a set of control parameters for each stage, including the heat transfer oil mode, temperature setpoint, flow rate benchmark, and acceleration / deceleration rate. This overcomes the limitation of a single strategy being unable to adapt to the changes in exothermic characteristics in the initial, middle, and later stages of the reaction, ensuring that each stage can be matched with the optimal temperature control mode. When the cumulative flow rate reaches the preset threshold and the reaction is fully completed... When preconditions are met, the system automatically switches stages, with each stage parameter executed only once. This achieves seamless adaptive control strategy integration and prevents logical confusion caused by repeated triggering. Furthermore, based on the flow rate baseline, cascade control of the reactor bottom temperature and feed flow rate is implemented, transforming the traditional "passive reliance on heat transfer oil for heat removal" into "actively adjusting the feed rate from the source to control heat release." This solves the lag problem of heat transfer oil and allows for advance reduction of feed when the temperature shows a runaway trend. Simultaneously, the system automatically and seamlessly switches the coordination strategy between hot and cold oil valves according to the heat transfer oil control mode, ensuring precise responses to heat removal or heating needs at different stages (e.g., heating for preheating, strong cooling for the middle stage, and heat preservation for the later stage). These synergistic technical features ultimately achieve automated, stage-by-stage adaptive high-precision temperature control throughout the entire reaction process, significantly suppressing temperature fluctuations, shortening the reaction cycle, reducing operational risks and manual intervention, and ensuring product quality stability. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this application or related technologies, the drawings used in the description of the embodiments of this application or related technologies will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a flowchart of a method for optimizing temperature control during the ethoxylation reaction stage in one embodiment; Figure 2(a) shows the flow chart of the temperature optimization control method for the ethoxylation reaction stage in another embodiment. Figure 1 ; Figure 2(b) is a flowchart of another embodiment of the temperature optimization control method for the ethoxylation reaction stage; Figure 3 This is a detailed flowchart of the ethoxylation stage control in one embodiment. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0022] It should be noted that the terms "first," "second," etc., used in this application can be used to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish the first element from the second element. The terms "comprising" and "having," and any variations thereof, used in this application, are intended to cover non-exclusive inclusion. The term "multiple" used in this application refers to two or more. The term "and / or" used in this application refers to one of the embodiments, or any combination of multiple embodiments.

[0023] To facilitate understanding of the technical solutions in the various embodiments of this application, a brief explanation of the technical terms that may appear in the various embodiments of this application is provided first: Ethoxylation, also known as ethoxylation, refers to the ring-opening addition reaction between ethylene oxide and compounds containing active hydrogen (such as alcohols, phenols, and amines). The products are collectively called ethoxy compounds. These compounds are usually nonionic surfactants, possessing both lipophilic groups and hydrophilic chains in their molecules. They exhibit excellent stability, acid and alkali resistance, and emulsifying, wetting, and dispersing properties, and are widely used in the textile, paper, coating, pharmaceutical, and daily chemical industries.

[0024] DCS (Distributed Control System) is a new type of computer control system relative to centralized control systems. It evolved from centralized control systems. It is a multi-level computer system composed of process control and process monitoring levels linked by a communication network. It integrates computer, communication, display, and control technologies (4C technologies). Its basic principles are distributed control, centralized operation, hierarchical management, flexible configuration, and convenient configuration.

[0025] For example, Figure 1 This is a flowchart of a method for optimizing temperature control during the ethoxylation reaction stage in one embodiment; such as... Figure 1 As shown, the method in this embodiment may include the following steps: Step S101: Obtain the cumulative ethylene oxide feed flow rate and use the cumulative ethylene oxide feed flow rate as the benchmark for judging the reaction progress.

[0026] In this embodiment, ethylene oxide (EO) is continuously added to the reactor as a reactant during the ethoxylation reaction. The DCS system collects the instantaneous feed flow rate of EO in real time via a flow meter and performs time integration calculations to obtain the cumulative EO feed flow rate. Since the cumulative amount of EO added directly determines the extent of the reaction (i.e., the reaction progress), this invention uses this cumulative amount as an objective benchmark for judging the reaction stage, replacing the traditional method that relies on manual judgment by the operator. The formula for calculating the cumulative EO amount is:

[0027] in, This represents the cumulative EO feed flow rate. This refers to the instantaneous feed rate of the EO module. This refers to the reaction time.

[0028] Step S102: Based on the cumulative flow rate of ethylene oxide feed, the ethoxylation reaction process is divided into multiple reaction stages, and a corresponding set of control parameters is preset for each reaction stage.

[0029] In this embodiment, based on the exothermic characteristics of the ethoxylation reaction (weak exothermic reaction in the initial stage, vigorous exothermic reaction in the middle stage, and weakening exothermic reaction in the later stage), and combined with production experience, the reaction process is divided into multiple stages based on the cumulative amount of EO. Seven heat transfer oil adjustment modes can be used to adapt to different stages of the ethoxylation production process, offering a wide range of applications. Different control modes can be selected according to the product's reaction characteristics. The applicable scope includes, but is not limited to, the following scenarios: During the preheating stage (room temperature → reaction start temperature), you can choose either Mode 2 (dual temperature cascade + ramp) or Mode 4 (single loop + ramp). At this time, you need to increase the temperature at a controllable rate to avoid local overheating.

[0030] In the initial stage of the reaction (after adding EO and starting to release heat), mode one (dual-temperature cascade split-range) can be selected. At this point, heat release begins, requiring a rapid switch from heating to cooling and stabilization of the material temperature. Cascade control can utilize the secondary loop of the heat transfer oil temperature control to quickly respond to changes in heat load and avoid overshoot.

[0031] During the mid-reaction phase (intense exothermic reaction followed by significant heat release), the following mode can be selected: Mode 6 (single-loop material temperature control, hot oil valve metering, PID-controlled cooling oil valve). In this mode, almost no heating is required, and the hot oil valve can be fixed at a small opening (e.g., 10-20%), solely to prevent over-cooling. All adjustment capacity is used for cooling, and the switching point of the split-range valve may introduce nonlinearity. Mode 6 is simpler and more stable.

[0032] In the later stages of the reaction (when exothermic reactions decrease), you can choose either Mode 1 (dual-temperature cascade split-loop) or Mode 3 (single-loop split-loop). With reduced heat release, reheating may be necessary to prevent a temperature drop. The split-loop mode allows for a smooth transition from full cooling to a heating + cooling equilibrium. The curing (insulation) process can be selected as: Mode 6 (material temperature single loop, hot oil valve quantitative, PID controlled cooling oil valve). During the curing stage, precise temperature control within a certain range is still required.

[0033] Cooling (rapid cooling) is available in Mode 7 (hot oil valve fully closed, PID-controlled cooling oil valve). Mode 7 is the simplest and most reliable, rapidly cooling to the discharge temperature.

[0034] Mode 5 serves as an auxiliary mode. First, set the heat transfer oil temperature reference, then use Mode 1 for fine-tuning the material temperature. Manually establish a reasonable heat transfer oil temperature reference (e.g., 110℃) to make it close to the actual required secondary loop setpoint, allowing the secondary loop (heat transfer oil temperature) to stabilize first and eliminate initial deviations. Then, switch to Mode 1. At this time, the output of the main controller (i.e., the secondary loop setpoint) only needs to be fine-tuned around 110℃, allowing the system to transition smoothly, shortening the adjustment time, and avoiding integral saturation.

[0035] In this embodiment, the linkage control of ethylene oxide and the bottom temperature of the reactor, along with the multi-mode coordination of the heat transfer oil, addresses the problems of low automation, unstable operator control, and high control difficulty in the reaction stage. It also optimizes the temperature control in other production stages. However, at this time, the settings of the reactor bottom temperature controller, the switching of heat transfer oil modes, and the temperature and ramp settings all require operator switching. This is to achieve more precise temperature control in the reaction stage and accelerate the reaction time.

[0036] In this embodiment, by introducing ethylene oxide feed flow accumulation, the actual progress of the ethoxylation reaction can be reflected. Based on the feed flow accumulation, multiple stages are defined, each with an activation switch and precondition checks to ensure no false triggering. Parameters can be adjusted at any time before the feed flow accumulation is reached. Each stage is controlled only once. Preset stage parameters can be stored in the preset parameter group P[N] and adjusted as needed. For example, if only six stages are activated, the following would be used: The 0kg segment, 0-200kg segment, 200kg-800kg segment, 800kg-1000kg segment, 1000kg segment, and 1000kg segment correspond to six stages: preheating, initial reaction stage, middle reaction stage, late reaction stage, ripening stage, and cooling stage, respectively. Of course, more stages can be divided when there is a need for more precise control.

[0037] Different feed rates and temperature control modes need to be adjusted at different stages of the reaction. Preset stage parameters are also set, and appropriate flow rates, reactor bottom temperatures, heat transfer oil modes, and temperature settings are determined based on the reaction characteristics of the product and production experience. Referring to the parameter preset table, in one specific embodiment, the reaction is divided into six stages: preheating, initial reaction, middle reaction, later reaction, maturation, and cooling. Each stage corresponds to a set of preset control parameters, including: heat transfer oil control mode, reactor bottom temperature setpoint (SP), EO feed flow rate reference value, and heating or cooling rate.

[0038] For example, the preset parameters for each stage can be configured with reference to Table 1. In actual applications, they can be adjusted according to specific product characteristics and production experience. Table 1 does not constitute a limitation on the scope of protection of this invention.

[0039] Table 1

[0040] Step S103: During the reaction process, the cumulative amount of ethylene oxide feed flow rate is calculated in real time. When the cumulative amount reaches the preset threshold corresponding to the current reaction stage and the preconditions are met, the system automatically switches to the next reaction stage and loads the control parameter group corresponding to that stage. The control parameter group of each stage is executed only once after the preconditions are met.

[0041] In this embodiment, the DCS system continuously calculates the accumulated EO during the reaction process and compares it with a preset stage trigger threshold. When the accumulated EO reaches the threshold set for the current stage and meets the preconditions corresponding to that stage (e.g., "feed valve open and flow rate ≠ 0" or "in cooling stage"), the system automatically performs a stage switch and loads the control parameter set for the next stage. Simultaneously, the system internally sets a status flag to ensure that the control parameter set for each stage is executed only once after the preconditions are met, preventing repeated triggering due to fluctuations in the accumulated EO or signal jitter.

[0042] For example, when the cumulative amount of EO increases from 0 kg and reaches ≥200 kg for the first time, and the current feed valve is open and the flow rate is not 0, the system automatically switches from "initial reaction" to "middle reaction" and loads the parameter group for the middle reaction: reactor temperature SP=112℃, EO flow rate reference value=600 kg / h, heat transfer oil mode=mode six, and hot oil valve fixed opening=15%.

[0043] Step S104: Based on the ethylene oxide feed flow rate reference value in the loaded control parameter group, perform cascade control of the reactor bottom temperature and ethylene oxide feed flow rate to actively adjust the heat release of the reaction; and based on the heat transfer oil control mode in the loaded control parameter group, automatically and seamlessly switch the control strategy of the heat transfer oil to meet the heat removal or heating requirements.

[0044] This embodiment includes two parallel core control strategies: 1) Bottom temperature-EO flow cascade control During the initial, middle, and later stages of the reaction, the system automatically engages temperature-flow cascade control. This cascade control uses a reactor bottom temperature PID controller as the main loop and an EO feed flow rate PID controller as the secondary loop. The main loop outputs a flow rate correction coefficient (e.g., 0.8~1.2) based on the deviation between the current reactor bottom temperature and the setpoint (SP). The secondary loop receives this correction coefficient, multiplies it by a preset EO flow rate reference value, and obtains the corrected flow rate setpoint, thereby adjusting the EO feed valve opening accordingly.

[0045] The advantages of this cascade control are: the fast-response flow secondary loop can "cover" all disturbances from fluid pressure and valve characteristics, while the slow temperature main loop only needs to focus on completing the final temperature control task. When the reaction shows a tendency to runaway, the temperature main loop will automatically reduce the flow correction coefficient, reduce the feed rate in advance, reduce the heat release of the reaction from the source, and achieve "active heat source control" rather than "passive heat removal". At the same time, the system retains the reactor temperature and reactor pressure protection logic in the original EO feed three-PID low-selection control. When the reactor bottom temperature or reaction pressure exceeds the safety threshold, the EO feed valve is closed first to ensure production safety.

[0046] 2) Seamless switching between multiple modes for heat transfer oil The system supports seven heat transfer oil control modes and can automatically and seamlessly switch between them based on the parameters loaded at the current stage (without abrupt changes in valve opening during switching). The seven modes are defined as follows: Mode 1: Dual-temperature cascade PID split-range control, with the main loop being the heat exchanger outlet material temperature and the secondary loop being the heat transfer oil outlet oil temperature; Mode 2: Based on Mode 1, the temperature setpoint increases from the starting value to the target value, and the rate of increase is determined by the heating rate or cooling rate parameter. Mode 3: Single-loop PID split-range control of heat exchanger outlet material temperature; Mode 4: Based on Mode 3, the temperature setpoint increases from the starting value to the target value, and the rate of increase is determined by the heating rate or cooling rate parameter. Mode 5: Single-loop PID split-range control of heat transfer oil outlet temperature; Mode 6: Single-loop PID control of heat exchanger outlet material temperature, quantitative opening of hot oil valve, and PID control of cold oil valve; Mode 7: Single-loop PID control of heat exchanger outlet material temperature, hot oil valve fully closed, PID control of cold oil valve; Among them, seamless switching between different modes is supported.

[0047] In this embodiment, the matching relationship between each stage and the heat transfer oil mode is as follows: In the preheating stage, mode two or mode four is used to raise the temperature at a controllable rate; in the initial stage of the reaction, mode five is switched to establish the heat transfer oil temperature reference, and then mode one is switched to fine-tune the material temperature; in the middle stage of the reaction, mode six is ​​used, and the hot oil valve is fixed at a small opening (such as 15%), with all adjustment capacity used for cooling; in the later stage of the reaction, mode one or mode three is used to smoothly transition to a state of heating and cooling equilibrium; in the maturation stage, mode six is ​​used to maintain a constant temperature; in the cooling stage, mode seven is used for rapid cooling.

[0048] It should be understood that the above methods are also applicable to strongly exothermic, staged batch reaction processes of propoxylation or polyesterification.

[0049] For example, Figure 2(a) is a flow chart of a method for optimizing temperature control during the ethoxylation reaction stage in another embodiment. Figure 1 Figure 2(b) is a flowchart of another embodiment of the temperature optimization control method for the ethoxylation reaction stage. As shown in Figures 2(a) and 2(b), this embodiment demonstrates the application scenario of the present invention from a full-process perspective. The ethoxylation production process includes, in sequence: production start, pre-ethoxylation stage, preheating, reaction, maturation, cooling, and post-ethoxylation stage. Among them, the stage temperature optimization control method of the present invention mainly targets the four key stages of preheating, reaction, maturation, and cooling for stage control.

[0050] In the pre-ethoxylation stage (including pre-vacuuming, heat transfer oil circulation, chain initiator feeding, circulation start-up, catalyst feeding, dehydration, enhanced vacuum, pre-reaction, etc.), the system is automatically executed by a batch control program without operator intervention. When the process enters the preheating stage, the stage control method of this invention takes effect, automatically executing the stage switching and parameter loading of preheating → reaction → ripening → cooling according to preset parameters. After cooling is completed, the system continues to execute subsequent stages (degassing, stripping, pressurization, neutralization, etc.) until production is finished.

[0051] In this embodiment, the cascade control of the bottom temperature and EO feed flow rate achieves a shift from "passive heat removal" to "active source control," overcoming the inherent lag in traditional heat transfer oil heat removal. The feed rate can be reduced in advance when a runaway temperature trend occurs. Simultaneously, this cascade control dynamically corrects the flow rate baseline value based on the actual bottom temperature deviation. When catalyst activity fluctuates or raw material quality changes, the system automatically adjusts the feed rate to match the actual reaction requirements, eliminating the problem of mismatch between a fixed feed rate and reaction demands. Using the cumulative EO amount as an objective benchmark to divide the process into stages and ensuring that parameters for each stage are executed only once replaces manual judgment, avoiding batch-to-batch variations. Combined with seamless switching between seven heat transfer oil modes and a batch control program, the entire process is automated with one-button start / stop, significantly reducing manual intervention and operational risks, and improving temperature control accuracy and product quality consistency.

[0052] For example, Figure 3 Here is a detailed flowchart of the ethoxylation stage control in one embodiment; such as Figure 3 As shown, the stage control process includes the following steps: Start stage control; Read the current cumulative EO amount; Determine if the cumulative EO amount has reached the current stage's preset threshold and if the preconditions are met. If not, return to continue monitoring; If yes, determine if the stage parameter group has already been executed. If yes, return to read the current cumulative EO amount to avoid repeated triggering; If not, load the preset parameter group for the next stage, including: kettle temperature SP, EO flow reference value, heat transfer oil mode, hot oil valve status, heating / cooling rate, etc.; Execute stage switching actions: update kettle temperature setpoint, switch feed control mode (disable / cascade), seamlessly switch heat transfer oil control mode, adjust hot oil valve opening, set heating / cooling rate; Mark the current stage parameter group as "executed" to prevent repeated triggering; Determine if this is the last stage. If yes, end stage control; If not, return to read the current cumulative EO amount and continue monitoring the trigger conditions for the next stage.

[0053] For example, the specific application process of the present invention will be described in detail using the production of nonylphenol polyoxyethylene ether in an ethoxylation device.

[0054] 1) Parking phase (system preparation and logic modification).

[0055] The following modifications were made to the DCS system: "Reactor bottom temperature - feed flow rate cascade" logic was added to the EO feed control logic; complete control logic for modes one to seven was added to the heat transfer oil control logic to ensure that each mode can be switched smoothly; a new "stage control" function module was added to support automatic stage switching and loading of corresponding parameters based on the cumulative EO amount.

[0056] 2) Parameter preset stage.

[0057] Based on production experience, configure the parameter groups for the six stages according to Table 1, enter them into the DCS system screen, and the operator can modify and save them online as needed.

[0058] 3) Automatic control stage of the reaction process.

[0059] Preheating stage: The system automatically switches the heat transfer oil to mode two, raising the kettle temperature from room temperature to 110°C at a rate of 3°C / min, and EO feeding is disabled.

[0060] 3) Initial stage of reaction: When the cumulative amount of EO reaches 0 kg and the feed valve is opened, the system first switches to mode five to establish the temperature reference of the heat transfer oil (about 110℃), and then switches to mode one; at the same time, temperature-flow cascade control is put into operation, the kettle temperature SP=112℃, and the EO flow reference=250 kg / h.

[0061] 4) Mid-reaction stage: When the cumulative amount of EO reaches 200 kg, the system automatically switches to mode six, the hot oil valve is fixed at 15% opening, the EO flow rate benchmark is increased to 600 kg / h, and the reactor temperature SP is maintained at 112℃.

[0062] 5) Later stage of reaction: When the cumulative amount of EO reaches 800 kg, the system switches to mode one, the EO flow rate baseline is reduced to 200 kg / h, and the reactor temperature SP is maintained at 112℃.

[0063] 6) Maturation stage: When the cumulative amount of EO reaches 1000 kg and the feed valve is closed, the system switches to mode six, the kettle temperature SP=110℃, and maintains a constant temperature until the maturation time ends.

[0064] 7) Cooling stage: After the curing is completed, the system switches to mode seven and the kettle temperature is reduced to 60°C at a rate of 3°C / min to prepare for discharge.

[0065] 8) Batch ended.

[0066] The batch control system executes subsequent production processes (discharging, cleaning, preparing for the next batch) or waits for operator instructions.

[0067] Through the application of this embodiment, the entire process of ethoxylation reaction is automated, the reaction temperature fluctuation is controlled within ±1℃, the batch reaction time is shortened by about 15%, the manual intervention is reduced by more than 90%, and the consistency of product quality between batches is significantly improved.

[0068] Through the above process, the system achieves automated, staged adaptive temperature control of the entire ethoxylation reaction process, significantly reducing manual intervention and improving temperature control accuracy and production safety.

[0069] This embodiment provides a temperature optimization and control device for the ethoxylation reaction stage. The device includes: a reaction progress judgment module, used to obtain the cumulative amount of ethylene oxide feed flow rate, and use the cumulative amount of ethylene oxide feed flow rate as the reaction progress judgment benchmark. The stage division and parameter preset module is used to divide the ethoxylation reaction process into multiple reaction stages based on the cumulative ethylene oxide feed flow rate, and preset a corresponding set of control parameters for each reaction stage. The set of control parameters includes: heat transfer oil control mode, reactor bottom temperature set value, ethylene oxide feed flow rate reference value, and heating rate or cooling rate. The automatic stage switching module is used to calculate the cumulative amount of ethylene oxide feed flow in real time during the reaction process. When the cumulative amount reaches the preset threshold corresponding to the current reaction stage and the preconditions are met, it automatically switches to the next reaction stage and loads the control parameter group corresponding to the stage. The control parameter group of each stage is executed only once after the preconditions are met. A temperature-flow cascade control module is used to perform cascade control of the reactor bottom temperature and ethylene oxide feed flow rate based on the ethylene oxide feed flow rate reference value in the loaded control parameter group, so as to actively adjust the heat of reaction; and The heat transfer oil multi-mode control module is used to automatically and seamlessly switch the control strategy of the heat transfer oil according to the heat transfer oil control mode in the loaded control parameter group, so as to meet the heat removal or heating requirements. The device is also suitable for strongly exothermic, staged batch reaction processes of propoxylation or polyesterification.

[0070] For example, the temperature-flow cascade control module is specifically used for: The reactor bottom temperature PID controller is used as the main loop, and the ethylene oxide feed flow PID controller is used as the secondary loop. The main circuit outputs a flow correction coefficient based on the deviation between the current bottom temperature and the set value, and the auxiliary circuit adjusts the opening of the ethylene oxide feed valve based on the flow correction coefficient and the adjusted flow set value. Furthermore, the device also includes a safety protection module for retaining the reactor temperature and reactor pressure protection logic in the three-PID low-select control of ethylene oxide feed, and prioritizing the shutdown of the feed valve under high temperature or high pressure conditions.

[0071] For example, the heat transfer oil multi-mode control module is specifically used to support switching between the following seven modes: Mode 1: Dual-temperature cascade PID split-range control; Mode 2: Dual-temperature cascade PID split-range control with ramp function, the ramp rate is determined by the heating rate or cooling rate parameter; Mode 3: Single-loop PID split-range control of heat exchanger outlet material temperature; Mode 4: Single-loop PID split-range control of the outlet material temperature of the heat exchanger with ramp function, the ramp rate is determined by the heating rate or cooling rate parameter; Mode 5: Single-loop PID split-range control of heat transfer oil outlet temperature; Mode 6: Single-loop PID control of heat exchanger outlet material temperature, with hot oil valve quantitative control; Mode 7: Single-loop PID control of heat exchanger outlet material temperature, with hot oil valve fully closed.

[0072] It should be understood that the above-mentioned apparatus is also suitable for strongly exothermic, staged batch reaction processes of propoxylation or polyesterification.

[0073] This embodiment provides a computer device, including a memory and a processor. The memory stores a computer program, and the processor executes the computer program to implement the above-described functionality. Figure 1 The steps in the method embodiment shown in Figure 2.

[0074] In one embodiment, a computer-readable storage medium is provided having a computer program stored thereon, which, when executed by a processor, implements the method steps of the various embodiments described above.

[0075] In one embodiment, a computer program product is provided, including a computer program that, when executed by a processor, implements the method steps of the various embodiments described above.

[0076] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. Any references to memory, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile memory and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM). The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this application may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, artificial intelligence (AI) processors, etc., and are not limited to these.

[0077] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this application.

[0078] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A method for optimizing and controlling the temperature during the ethoxylation reaction stage, characterized in that, The method includes: The cumulative ethylene oxide feed flow rate is obtained, and the cumulative ethylene oxide feed flow rate is used as the benchmark for judging the reaction progress. Based on the cumulative ethylene oxide feed flow rate, the ethoxylation reaction process is divided into multiple reaction stages, and a corresponding set of control parameters is preset for each reaction stage. The set of control parameters includes: heat transfer oil control mode, reactor bottom temperature set value, ethylene oxide feed flow rate reference value, and heating rate or cooling rate. During the reaction, the cumulative amount of ethylene oxide feed flow is calculated in real time. When the cumulative amount reaches the preset threshold corresponding to the current reaction stage and the preconditions are met, the system automatically switches to the next reaction stage and loads the control parameter group corresponding to that stage. The control parameter group of each stage is executed only once after the preconditions are met. Based on the ethylene oxide feed flow rate reference value in the loaded control parameter group, cascade control of the reactor bottom temperature and ethylene oxide feed flow rate is performed to actively adjust the heat release of the reaction; and based on the heat transfer oil control mode in the loaded control parameter group, the control strategy of the heat transfer oil is automatically and seamlessly switched to meet the heat removal or heating requirements. The method is also applicable to strongly exothermic, staged batch reaction processes of propoxylation or polyesterification.

2. The method according to claim 1, characterized in that, The cascade control of the reactor bottom temperature and ethylene oxide feed flow rate includes: The reactor bottom temperature PID controller is used as the main loop, and the ethylene oxide feed flow PID controller is used as the secondary loop. The main circuit outputs a flow correction coefficient based on the deviation between the current bottom temperature and the set value, and the secondary circuit adjusts the opening of the ethylene oxide feed valve based on the flow correction coefficient and the adjusted flow set value. Furthermore, the reactor temperature and reactor pressure protection logic in the three-PID low-selection control of ethylene oxide feed is retained, and the feed valve is closed preferentially under high temperature or high pressure conditions.

3. The method according to claim 1, characterized in that, The heat transfer oil control mode includes at least one of the following: Mode 1: Dual-temperature cascade PID split-range control, with the main loop being the heat exchanger outlet material temperature and the secondary loop being the heat transfer oil outlet oil temperature; Mode 2: Based on Mode 1, the temperature setpoint increases from the starting value to the target value, and the rate of increase is determined by the heating rate or cooling rate parameter. Mode 3: Single-loop PID split-range control of heat exchanger outlet material temperature; Mode 4: Based on Mode 3, the temperature setpoint increases from the starting value to the target value, and the rate of increase is determined by the heating rate or cooling rate parameter. Mode 5: Single-loop PID split-range control of heat transfer oil outlet temperature; Mode 6: Single-loop PID control of heat exchanger outlet material temperature, quantitative opening of hot oil valve, and PID control of cold oil valve; Mode 7: Single-loop PID control of heat exchanger outlet material temperature, hot oil valve fully closed, PID control of cold oil valve; Among them, seamless switching between different modes is supported.

4. The method according to claim 3, characterized in that, The automatic and seamless switching control strategy for heat transfer oil based on the heat transfer oil control mode in the loaded control parameter group includes: During the preheating stage, switch to mode two or mode four and heat to the reaction initiation temperature at the rate set by the heating rate or cooling rate parameter. In the initial stage of the reaction, first switch to mode five to establish the temperature reference of the heat transfer oil, and then switch to mode one to fine-tune the material temperature; During the middle of the reaction, switch to mode six, fix the opening of the hot oil valve, and use PID control to remove heat from the cold oil valve; In the later stages of the reaction, switch to mode one or mode three to smoothly transition to a state of heating and cooling equilibrium. During the ripening stage, switch to mode six to maintain a constant temperature; During the cooling phase, switch to mode seven, fully close the hot oil valve, and use PID control to cool the cold oil valve at the rate set by the heating rate or cooling rate parameter.

5. The method according to any one of claims 1 to 4, characterized in that, The plurality of reaction stages include at least: a preheating stage, an initial reaction stage, a middle reaction stage, a later reaction stage, a ripening stage, and a cooling stage; Specifically, during the preheating and initial reaction stages, ethylene oxide feed flow control is disabled or set to a low flow reference value; during the initial, middle, and later stages of the reaction, the cascade control is automatically activated; and during the maturation and cooling stages, the ethylene oxide feed valve is closed, and feed flow control is disabled.

6. A device for optimizing and controlling the temperature of an ethoxylation reaction stage, characterized in that, The device includes: The reaction progress judgment module is used to obtain the cumulative amount of ethylene oxide feed flow rate and use the cumulative amount of ethylene oxide feed flow rate as the reaction progress judgment benchmark. The stage division and parameter preset module is used to divide the ethoxylation reaction process into multiple reaction stages based on the cumulative ethylene oxide feed flow rate, and preset a corresponding set of control parameters for each reaction stage. The set of control parameters includes: heat transfer oil control mode, reactor bottom temperature set value, ethylene oxide feed flow rate reference value, and heating rate or cooling rate. The automatic stage switching module is used to calculate the cumulative amount of ethylene oxide feed flow in real time during the reaction process. When the cumulative amount reaches the preset threshold corresponding to the current reaction stage and the preconditions are met, it automatically switches to the next reaction stage and loads the control parameter group corresponding to the stage. The control parameter group of each stage is executed only once after the preconditions are met. A temperature-flow cascade control module is used to perform cascade control of the reactor bottom temperature and ethylene oxide feed flow rate based on the ethylene oxide feed flow rate reference value in the loaded control parameter group, so as to actively adjust the heat of reaction; and The heat transfer oil multi-mode control module is used to automatically and seamlessly switch the control strategy of the heat transfer oil according to the heat transfer oil control mode in the loaded control parameter group, so as to meet the heat removal or heating requirements. The device is also suitable for strongly exothermic, staged batch reaction processes of propoxylation or polyesterification.

7. The apparatus according to claim 6, characterized in that, The temperature-flow cascade control module is specifically used for: The reactor bottom temperature PID controller is used as the main loop, and the ethylene oxide feed flow PID controller is used as the secondary loop. The main circuit outputs a flow correction coefficient based on the deviation between the current bottom temperature and the set value, and the auxiliary circuit adjusts the opening of the ethylene oxide feed valve based on the flow correction coefficient and the adjusted flow set value. Furthermore, the device also includes a safety protection module for retaining the reactor temperature and reactor pressure protection logic in the three-PID low-select control of ethylene oxide feed, and prioritizing the shutdown of the feed valve under high temperature or high pressure conditions.

8. The apparatus according to claim 6, characterized in that, The heat transfer oil multi-mode control module is specifically used to support switching between the following seven modes: Mode 1: Dual-temperature cascade PID split-range control; Mode 2: Dual-temperature cascade PID split-range control with ramp function, the ramp rate is determined by the heating rate or cooling rate parameter; Mode 3: Single-loop PID split-range control of heat exchanger outlet material temperature; Mode 4: Single-loop PID split-range control of the outlet material temperature of the heat exchanger with ramp function, the ramp rate is determined by the heating rate or cooling rate parameter; Mode 5: Single-loop PID split-range control of heat transfer oil outlet temperature; Mode 6: Single-loop PID control of heat exchanger outlet material temperature, with hot oil valve quantitative control; Mode 7: Single-loop PID control of heat exchanger outlet material temperature, with hot oil valve fully closed.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the steps of the method according to any one of claims 1 to 5.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1 to 5.

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