Automatic cooling system and cooling method for acid chlorination of insecticidal monomer preparation

Abstract

The application relates to the technical field of cooling process control, in particular to an automatic cooling system and a cooling method for the preparation of a single insecticide, the method comprising the following steps: acquiring temperature mutation amplitude at each sampling time in a sampling period in an acid chlorination process, identifying abnormal temperature mutation by using a threshold value, and calculating temperature continuous mutation value; screening a high temperature value in a kettle; analyzing the difference between the high temperature value in the kettle and a kettle evaporation threshold value in the sampling period, combining the distribution characteristics of the pressure in the kettle in the sampling period and a prediction result, obtaining a dichloroethane evaporation weight, and obtaining chlorination superheat in the sampling period; analyzing the trend characteristics of chlorine flow in the sampling period, combining the chlorination superheat, and obtaining cooling adjustment strength in the sampling period; and jointly controlling temperature by adjusting chlorine flow and jacket circulating cooling water flow rate, and giving consideration to the chlorination reaction efficiency and cooling capacity of the chlorination kettle.

Description

Technical Field

[0001] This application relates to the field of cooling process control technology, specifically to an automatic acid chlorination cooling system and cooling method for the preparation of insecticides. Background Technology

[0002] As a nereistoxin-based insecticide, the preparation process of chlorpyrifos mainly consists of key steps such as amination, acid chlorination, thiosulfate, crystallization centrifugation, scraped film evaporation, and drying. The core function of the acid chlorination step is to convert dimethylallylamine generated in the amination stage into chloride hydrochloride, providing chlorpyrifos intermediates for the subsequent thiosulfate step. This step can be divided into three parts: acidification, dehydration, and chlorination.

[0003] According to process requirements, the temperature of the chlorination reactor needs to be strictly controlled below 85℃ during the chlorination process. If the temperature is too high, it will lead to a decrease in yield, an increase in the amount of chlorine gas escaping from the tail gas, and even safety risks. Since the chlorination reaction is an exothermic reaction, the existing cooling method for the chlorination reactor mainly relies on adjusting the opening of the jacket circulating cooling water valve. However, industrial chlorination reactors have large capacities, and the cooling control is lagging. Under industrial production conditions, when the temperature of the chlorination reactor changes due to overheating, the acid chlorination cooling system cannot match the chlorine flow rate and cooling demand in time, which can easily lead to short-term overheating, resulting in a large amount of dichloroethane and chlorine gas escaping, and a decrease in product purity. Summary of the Invention

[0004] In view of the above, it is necessary to provide an automatic acid chlorination cooling system and cooling method for the preparation of insecticides to solve the above problems.

[0005] The first aspect of this application provides an automated cooling method for acid chlorination in the preparation of insecticides, the method comprising:

[0006] For each control moment in the acid chlorination process, the pressure inside the vessel, the temperature inside the vessel, and the chlorine flow rate at each moment within the preset sampling period are obtained;

[0007] The numerical distribution of the temperature difference between adjacent moments in the vessel within the sampling period is analyzed. All moments are filtered based on a threshold segmentation algorithm to obtain the proportion of abnormal mutation time series. The dispersion of all temperature data within the sampling period is analyzed, and combined with the proportion of abnormal mutation time series, the continuous temperature mutation value of the sampling period is obtained.

[0008] The in-vessel temperature at each moment within the sampling period is compared with the preset in-vessel evaporation threshold to screen for high-temperature values ​​in the vessel; the difference distribution between the high-temperature values ​​in the vessel and the in-vessel evaporation threshold in the sampling period is analyzed, and the distribution characteristics and prediction results of the pressure in the vessel during the sampling period are compared to obtain the dichloroethane evaporation weight of the sampling period. Combined with the continuous temperature change value during the sampling period, the chlorination superheat of the sampling period is obtained.

[0009] The trend characteristics of chlorine flow rate during the sampling period are analyzed, and the cooling regulation intensity during the sampling period is obtained in combination with the chlorination superheat. Based on the value of the cooling regulation intensity during the sampling period, and in combination with the distribution of circulating cooling water flow rate and chlorine flow rate during the sampling period, the circulating cooling water flow rate and chlorine flow rate at each control moment are controlled.

[0010] Preferably, the percentage of anomalous mutation time series is obtained as follows:

[0011] Calculate the absolute value of the temperature difference between the inside of the vessel at each moment within the sampling period and the previous moment, and use it as the temperature change amplitude at each moment;

[0012] A threshold segmentation algorithm is used to segment all temperature change amplitudes within the sampling period to obtain a segmentation threshold. The time when the temperature change amplitude is greater than the segmentation threshold is recorded as the abnormal change time series value.

[0013] Calculate the percentage of abnormal mutation time series values ​​in all time periods within the sampling period to obtain the percentage of abnormal mutation time series values ​​in the sampling period.

[0014] Preferably, the temperature mutation value of the sampling period is specifically the positive fusion result of the standard deviation of all temperature data within the sampling period and the proportion of the abnormal mutation time sequence.

[0015] Preferably, the high temperature value inside the vessel is specifically the temperature inside the vessel that is greater than or equal to the evaporation threshold within the vessel during the sampling period.

[0016] Preferably, the method for obtaining the dichloroethane evaporation weight for the sampling period is as follows:

[0017] Based on the pressure inside the vessel at all times during the sampling period, the pressure inside the vessel at the next time moment is predicted; the ratio between the predicted pressure value and the average pressure inside the vessel at all times during the sampling period is calculated and denoted as the first ratio.

[0018] Calculate the difference between the high temperature value inside the vessel and the evaporation threshold inside the vessel during each sampling period, and divide it by the evaporation threshold inside the vessel to obtain the second ratio;

[0019] The second ratio of all high-temperature values ​​inside the vessel during the sampling period is accumulated and positively merged with the first ratio to obtain the dichloroethane evaporation weight for the sampling period.

[0020] Preferably, the chlorination superheat of the sampling period is specifically the product of the continuous temperature change value and the weight of dichloroethane evaporation.

[0021] Preferably, the cooling adjustment intensity for obtaining the sampling period is specifically as follows:

[0022] A trend verification algorithm is used to normalize the obtained trend statistics for chlorine flow rate at all times within the sampling period to obtain the chlorine trend assessment value.

[0023] The normalized value obtained by positively fusing the chlorine trend assessment value with the chlorination superheat is used as the cooling adjustment intensity within the sampling period.

[0024] Preferably, the condition for controlling the circulating cooling water flow rate and chlorine flow rate at each control moment is that the cooling adjustment intensity of the sampling period is greater than or equal to the preset cooling threshold.

[0025] Preferably, the specific method for controlling the circulating cooling water flow rate and chlorine flow rate at each control moment is as follows:

[0026] Calculate the average circulating cooling water flow rate and the average chlorine flow rate at all times within the sampling period; calculate the sum of the natural number 1 and the cooling regulation force, and use the product of the sum and the average circulating cooling water flow rate as the circulating cooling water flow rate at the corresponding control time; use the product of the sum and the average chlorine flow rate as the chlorine flow rate at the corresponding control time.

[0027] Secondly, embodiments of this application also provide an automatic acid chlorination cooling system for preparing insecticides, including a memory, a processor, and a computer program stored in the memory and running on the processor, wherein the processor executes the computer program to implement the steps of any of the methods described above.

[0028] The beneficial effects of the above scheme are as follows: This application firstly monitors parameters such as pressure, temperature and chlorine flow rate in the chlorination reactor in real time by setting multiple sensors, and then controls the chlorine flow rate and jacket circulating cooling water flow rate together by combining the cooling adjustment intensity and segmented cooling threshold. This achieves precise control of the chlorination reactor temperature, effectively avoids overheating problems caused by cooling lag, and improves the cooling effect and response speed of the acid chlorination cooling system.

[0029] Secondly, this application improves the accuracy of superheat assessment of the solvent in the chlorination reactor by monitoring temperature fluctuations of the solvent in the chlorination reactor and constructing a chlorination superheat by combining the weight of dichloroethane evaporation. This reduces the problems of decreased product purity and yield caused by local overheating or dichloroethane evaporation, suppresses side reactions in the chlorination reaction, and improves the reaction purity and yield in the preparation of insecticide. At the same time, it prevents safety risks such as large-scale escape of dichloroethane and chlorine due to overheating, thus enhancing production safety.

[0030] Finally, this application adjusts the flow rate of circulating cooling water and the flow rate of chlorine gas in stages according to the cooling requirements of the chlorination reactor, thereby achieving optimized allocation of cooling resources, avoiding over-cooling or under-cooling, and balancing the chlorination reaction efficiency and cooling capacity of the chlorination reactor. Attached Figure Description

[0031] Figure 1 A flow chart of the acid-chlorine process in the preparation process of an insecticide provided in one embodiment of this application;

[0032] Figure 2 This is a flowchart illustrating the steps of an automatic cooling method for acid chlorination in the preparation of insecticides, provided in one embodiment of this application. Detailed Implementation

[0033] In the description of the embodiments in this application, the words "exemplary," "or," and "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design scheme described as "exemplary" or "for example" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or design schemes. Specifically, the use of the words "exemplary," "or," and "for example" is intended to present the relevant concepts in a specific manner.

[0034] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in this application's specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0035] It should also be noted that the terms "first" and "second" in this application and its accompanying drawings are used to distinguish similar objects, rather than to describe a specific order or sequence. The methods disclosed in the embodiments of this application or the methods shown in the flowcharts include one or more steps for implementing the method. Without departing from the scope of protection of this application, the execution order of multiple steps can be interchanged, and some steps can also be deleted.

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0037] The following, in conjunction with the accompanying drawings, details the specific scheme of the automatic acid chlorination cooling system and cooling method for preparing insecticides provided in this application.

[0038] The flow chart of the acid-chlorine process in the preparation process of the insecticide in this application is as follows: Figure 1 As shown, this process includes the following steps:

[0039] First, check whether the equipment, pipelines, valves and refrigeration conditions of the acid chlorination process are normal. Then, open the refrigerated brine valves of the graphite condenser and the acidification kettle jacket to cool down the equipment.

[0040] S1, Acidification: Dimethylallylamine reacts with hydrochloric acid to form dimethylallylamine hydrochloride.

[0041] Dimethylallylamine (the product of the amination process) from the previous stage is added to the acidification reactor. The stirring device of the acidification reactor is turned on, and hydrochloric acid is pumped into the acidification reactor from the high-level metering tank. Acid addition begins when the temperature is below 30°C. As an example, the temperature of the acidification reactor is controlled at ≤25°C. In particular, the acid addition rate should be slow in the early stage of acidification to reduce the volatilization of allylamine due to temperature rise and ensure the yield of acidification.

[0042] S2, Dehydration: Removes water from dimethylallylamine hydrochloride to prevent subsequent chlorination side reactions.

[0043] Turn on the water pump for dehydration and feed the acidified dimethylallylamine hydrochloride into the dehydration vessel. After all the dimethylallylamine hydrochloride has entered the dehydration vessel, start the agitator and then turn on the steam to heat and dehydrate. When the vessel temperature reaches between 110 and 135°C, the vacuum reaches above 0.08 MPa, and no water is discharged from the steam outlet, the dehydration can be considered complete.

[0044] S3, Chlorination: Dimethylallylamine hydrochloride is passed through dichloroethane solvent with chlorine gas to produce chloride hydrochloride.

[0045] Dichloroethane was added to the dehydrated dimethylallylamine hydrochloride in the dehydration vessel, and then the mixture was transferred to the chlorination vessel. The stirring in the chlorination vessel was turned on, and the circulating cooling water valve of the chlorination vessel jacket was opened to allow the circulating cooling water to flow into the chlorination vessel jacket for cooling. When the temperature of the chlorination vessel was below 85°C, chlorine gas was slowly introduced. The cooling of the chlorination vessel was controlled by the acid chlorination automatic cooling system to prevent the chlorination vessel from overheating in a short time, which would cause a large amount of dichloroethane and chlorine gas to escape and reduce the purity of the product.

[0046] Because the cooling of chlorination reactors primarily relies on adjusting the opening of the jacketed circulating cooling water valves, and industrial chlorination reactors have large capacities, cooling control exhibits a certain degree of lag. Under industrial production conditions, when the temperature of the chlorination reactor becomes too high, the acid chlorination cooling system struggles to adjust the chlorine flow rate and cooling demand in a timely manner, leading to overheating within a short period. This overheating can result in incomplete chlorination, causing a large amount of dichloroethane and chlorine gas to escape, thereby reducing the purity of the product and posing safety hazards.

[0047] Based on this, one embodiment of this application provides an automated cooling method for acid chlorination in the preparation of insecticides, the flowchart of which is shown below. Figure 2 As shown, the method includes the following steps:

[0048] Step 1: For each control moment in the acid chlorination process, obtain the pressure inside the vessel, the temperature inside the vessel, and the chlorine flow rate at each moment within the preset sampling period.

[0049] This application involves installing a pressure sensor on the top of the chlorination reactor to measure the pressure inside the reactor, and inserting a Pt100 resistance temperature sensor into the glass-lined thermometer sleeve to measure the temperature of the solvent inside the reactor. A thermal mass flow meter is installed on the chlorine gas vent of the chlorination reactor to measure the flow rate of chlorine gas entering the reactor.

[0050] In this application, the sampling frequency of the pressure sensor, the resistance temperature detector, and the thermal mass flow meter is all set to 1Hz. The control interval of the automatic cooling system for acid chlorination is set to Qmin, meaning that the automatic cooling system for acid chlorination is adjusted once every Qmin. The control interval Q is set to [0.5, 5], and in this embodiment, it is set to 2min. Before the control time, this application acquires a sampling period of length Q, and acquires the pressure sequence, temperature sequence, and chlorine flow rate sequence inside the vessel during the sampling period.

[0051] Step 2: Analyze the numerical distribution of the temperature difference between adjacent moments in the vessel within the sampling period, filter all moments based on the threshold segmentation algorithm to obtain the proportion of abnormal mutation time series; analyze the dispersion of all temperature data within the sampling period, and combine the abnormal mutation time series proportion to obtain the continuous temperature mutation value of the sampling period.

[0052] In the chlorination reaction of insecticide preparation, the substitution reaction between chlorine and dimethylallylamine hydrochloride releases a large amount of heat. Continuous chlorination reaction requires timely matching of the dynamic balance between feed, reaction and cooling. Large industrial chlorination reactors have large volumes, which can easily lead to continuous sudden changes in the temperature of the chlorination reaction solvent and local overheating, resulting in chlorination side reactions and reducing product yield.

[0053] This application acquires the in-vessel temperature sequence during the sampling period and calculates the absolute value of the difference between the i-th data element and the (i-1)-th data element as the temperature mutation amplitude of the i-th data element. It's important to note that when i=1, the mean of the in-vessel temperature sequence is used as the data element for i=0, and this is used to calculate the temperature mutation amplitude of the i-th data element. All temperature mutation amplitudes are used as input to the OTU algorithm to obtain a segmentation threshold. The time values ​​where the temperature mutation amplitude is greater than the segmentation threshold are recorded as abnormal mutation time series values. The proportion of abnormal mutation time series values ​​in the in-vessel temperature sequence is counted and recorded as the abnormal mutation time series proportion.

[0054] The standard deviation of all data elements in the temperature sequence within the reactor is calculated and positively fused with the proportion of anomalous abrupt changes in time series to obtain the sustained temperature abrupt change value for the chlorination reactor sampling period. In this embodiment, the positive fusion of variables is performed using a multiplication calculation method.

[0055] It should be understood that the standard deviation of all data elements in the temperature sequence inside the reactor is used to reflect the randomness of the temperature change of the chlorination reaction solvent in the chlorination reactor during the sampling period; the proportion of abnormal mutation time sequence reflects the frequency of abnormal temperature mutation in the chlorination reactor during the sampling period. The larger the value, the stronger the persistence of abnormal temperature mutation in the chlorination reaction solvent, and the more it can eliminate random errors caused by sensor failure. In this case, the larger the value of continuous temperature mutation in the sampling period of the chlorination reactor.

[0056] Step 3: Compare the in-vessel temperature at each moment within the sampling period with the preset in-vessel evaporation threshold to screen the high-temperature values ​​in the vessel; analyze the difference distribution between the high-temperature values ​​in the vessel and the in-vessel evaporation threshold during the sampling period, compare the distribution characteristics of the pressure in the vessel during the sampling period with the prediction results to obtain the dichloroethane evaporation weight of the sampling period, and combine the continuous temperature change value during the sampling period to obtain the chlorination superheat of the sampling period.

[0057] During the chlorination reaction in the chlorination reactor, if the solvent's solubility is insufficient, undissolved solid particles will remain in the reaction system. This causes chlorine gas to react only with the surface of the particles, preventing the internal particles from participating in the reaction and thus preventing the chlorination reaction from completing. Dichloroethane, as a non-polar halocarbon solvent, can effectively dissolve dimethylallylamine hydrochloride, forming a homogeneous reaction system. The moisture content is directly related to the degree of side reactions in the chlorination reaction; adding dichloroethane for dehydration is key to suppressing these side reactions.

[0058] Since chlorination is an exothermic reaction, and increasing the temperature can accelerate the chlorination process, further increasing the temperature of the solvent in the chlorination reactor, and given that dichloroethane has a boiling point of 83.5℃, timely automatic cooling is necessary during the chlorination reaction. This is to prevent the chlorination reaction from entering a violently exothermic phase, and also to prevent dichloroethane from volatilizing, reducing the solvent temperature, leading to an uneven reaction system, and decreasing the yield and purity of the chlorination products.

[0059] In this application, an in-reactor evaporation threshold is set to prevent the evaporation of dichloroethane. Among them, the in-pot evaporation threshold This embodiment takes into account the control lag of large industrial chlorination reactors and the evaporation threshold inside the reactor. The temperature is set at 75℃, but the specific parameters can be adjusted by the implementers. In this application, the temperature values ​​in the temperature sequence inside the vessel during the sampling period that are greater than or equal to the evaporation threshold inside the vessel are recorded as the high temperature values ​​inside the vessel.

[0060] Normally, the temperature inside the reactor is below the evaporation threshold, and the main reaction, chlorination, occurs primarily. Chlorine gas is passed through dimethylallylamine hydrochloride to form chloride hydrochloride, which dissolves in dichloroethane. The pressure change inside the reactor is minimal. However, if dichloroethane evaporates at high temperatures, it can cause a rapid increase in both temperature and pressure. This application obtains the pressure sequence inside the chlorination reactor during a sampling period. This pressure sequence is used as input to a time series prediction algorithm, and the predicted value of the pressure sequence at the next moment is output, denoted as... The prediction algorithm can be SMA (Simple Moving Average), EMA (Exponential Moving Average), or WMA (Weighted Moving Average). In this embodiment, the EMA algorithm is used for time series prediction.

[0061] Furthermore, based on the pressure inside the vessel at all times during the sampling period, the pressure inside the vessel at the next time moment is predicted; the ratio between the predicted pressure value and the average pressure inside the vessel at all times during the sampling period is calculated and recorded as the first ratio; the difference between each high temperature value inside the vessel and the evaporation threshold inside the vessel during the sampling period is calculated and divided by the evaporation threshold inside the vessel to obtain the second ratio; the second ratios of all high temperature values ​​inside the vessel during the sampling period are accumulated and positively fused with the first ratio to obtain the dichloroethane evaporation weight for the sampling period.

[0062] In this embodiment, the dichloroethane evaporation weight of the sampling cycle in the chlorination reactor is obtained using the following formula. : In the formula, This is the j-th high-temperature value inside the chlorination reactor during the sampling period. It is the total number of high-temperature values ​​inside all reactors during the sampling period of the chlorination reactor. It is the mean of all data elements in the pressure sequence inside the chlorination reactor during the sampling period. This represents the predicted pressure inside the vessel at the next moment. Indicates the evaporation threshold inside the vessel. Indicates the first ratio. This indicates the second ratio.

[0063] This indicator reflects the likelihood of dichloroethane forming in the solvent within the reactor during a chlorination reaction. The higher the solvent temperature exceeds the reactor's evaporation threshold, the more likely dichloroethane is to evaporate at high temperatures. This is used to reflect the urgency of the chlorination reactor in the high-temperature evaporation of dichloroethane. The larger the value, the more dichloroethane will evaporate subsequently. The less solvent is used in the chlorination reaction, the more important it is to prevent high-temperature evaporation of dichloroethane in the chlorination reactor. The weight of dichloroethane evaporation... The larger.

[0064] This application obtains the continuous temperature abrupt change value and dichloroethane evaporation weight during the sampling period within the chlorination reactor to determine the chlorination superheat during the sampling period, which is used to evaluate the solvent superheat during the chlorination reaction. The chlorination superheat is positively correlated with the continuous temperature abrupt change value and the dichloroethane evaporation weight. In this embodiment, the chlorination superheat during the sampling period can be obtained by calculating the product of the continuous temperature abrupt change value and the dichloroethane evaporation weight.

[0065] The sustained temperature change value is used to reflect the sustained temperature change characteristics of the solvent in the chlorination reactor during the chlorination reaction. The larger the sustained temperature change value, the more likely local overheating is to occur in the chlorination reactor, causing a sudden change in the temperature of the solvent in the chlorination reactor, and the longer the duration, the greater the degree of chlorination overheating.

[0066] The dichloroethane evaporation weight is used to reflect the superheat weight caused by the evaporation of dichloroethane during the chlorination reaction. In order to avoid excessive evaporation of dichloroethane causing a reduction in the solvent of the chlorination reaction, resulting in an uneven reaction system and a decrease in the yield and purity of the chlorination reaction products, a higher superheat weight should be given to the solvent temperature of the chlorination reactor to ensure the content of dichloroethane solvent in the chlorination reaction.

[0067] Step four analyzes the trend characteristics of chlorine flow rate during the sampling period, and combines the chlorination superheat to obtain the cooling regulation intensity during the sampling period; based on the value of the cooling regulation intensity during the sampling period, and combined with the distribution of circulating cooling water flow rate and chlorine flow rate during the sampling period, the circulating cooling water flow rate and chlorine flow rate at each control moment are controlled.

[0068] In chlorination reactors, cooling is typically controlled by adjusting the chlorine gas flow rate at the reactor's gas inlet and the flow rate of the circulating cooling water within the reactor jacket. The chlorine gas flow rate controls the chlorination reaction process; reducing the flow rate decreases the reaction rate and reduces the risk of excessive localized heat release. Simultaneously, the flow rate of the circulating cooling water reflects the reactor's heat exchange efficiency; a faster flow rate results in higher heat exchange efficiency and stronger cooling effect.

[0069] In the cooling control process of chlorination reaction, reducing the chlorination flow rate can easily prolong the chlorination reaction time, reduce production efficiency, and increase energy consumption. However, the heat exchange efficiency of the chlorination vessel is limited, making it difficult to cope with the severe overheating phenomenon. Therefore, it is necessary to implement combined cooling control of the chlorination vessel to balance the chlorination reaction efficiency and cooling capacity.

[0070] This application obtains the chlorine flow rate sequence of the chlorination reactor during the sampling period and uses this sequence as input to the Mann-Kendall trend verification algorithm to obtain the normalized trend statistics of the chlorine flow rate sequence, which is denoted as the chlorine trend evaluation value. The chlorine trend evaluation value is then positively integrated with the chlorination superheat to obtain the cooling regulation intensity within the sampling period.

[0071] In one embodiment of this application, the cooling adjustment intensity of the chlorination reactor sampling cycle is obtained using the following formula. : In the formula, It is the chlorine trend assessment value of the chlorine flow rate sequence during the sampling period inside the chlorination reactor. It is the chlorination superheat during the sampling period in the chlorination reactor, exp() is an exponential function with the natural constant e as the base, and norm[] is the normalization function.

[0072] Chlorination superheat Used to reflect the degree of solvent overheating caused by the chlorination reaction in the chlorination reactor, taking into full account the possibility of dichloroethane evaporation, chlorination overheating. To avoid excessive evaporation of dichloroethane, reduce the solvent content in the chlorination reaction, and eliminate localized overheating within the chlorination reactor, a stronger cooling control system should be adopted. The larger. Used to reflect the chlorination trend inside the chlorination reactor. The larger the value, the more likely it is that the chlorine gas flow rate in the chlorination reactor is increasing, which makes it easier for the solvent temperature to rise sharply. Therefore, increasing the cooling control level of the chlorination reactor is crucial. The larger.

[0073] This application achieves cooling control of the chlorination reactor in the chlorination process of insecticide monoacids through the following method:

[0074] (1) If the cooling adjustment force of the chlorination reactor sampling cycle If the flow rate is below the cooling threshold, it indicates that localized overheating within the chlorination reactor is not significant, and the chlorine flow rate does not show a marked increasing trend. In this case, to avoid adjusting the chlorine flow rate, extending the chlorination reaction time, reducing production efficiency, and increasing energy consumption, adjusting the flow rate of the circulating cooling water in the chlorination reactor is sufficient. This application uses the formula... Obtain the flow rate adaptation value of the circulating cooling water in the chlorination reactor. ,in, This is the average flow rate of the jacketed circulating cooling water during the sampling period of the chlorination reactor. The flow rate of the jacketed circulating cooling water in the chlorination reactor is set to [value] at the control time. This completes the cooling control of the chlorination reactor. In this embodiment, the cooling threshold is set to 0.6.

[0075] (2) If the cooling adjustment force of the chlorination reactor sampling cycle A reading greater than or equal to the cooling threshold indicates significant localized overheating within the chlorination reactor and a significant increase in chlorine flow rate. To avoid insufficient heat exchange efficiency and enhance the cooling capacity of the chlorination reactor, this application employs a combined cooling control system, controlling both the circulating cooling water flow rate and the chlorine flow rate. This application utilizes a formula... Obtain the flow rate adaptation value of the circulating cooling water in the chlorination reactor. Through formula The formula for obtaining the flow rate adaptation value of chlorine gas flow in the chlorination reactor. The flow rate of the jacketed circulating cooling water in the chlorination reactor is set at the control time. chlorine flow rate is This completes the cooling control of the chlorination reactor.

[0076] Based on the same inventive concept as the above methods, embodiments of this application also provide an automatic acid-chlorination cooling system for preparing insecticides, including a memory, a processor, and a computer program stored in the memory and running on the processor. When the processor executes the computer program, it implements the steps of any one of the above-described automatic acid-chlorination cooling methods for preparing insecticides.

[0077] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to embodiments of this application. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. In some alternative implementations, the functions marked in the blocks may occur in a different order than that shown in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. In the descriptions corresponding to the flowcharts and block diagrams in the accompanying drawings, the operations or steps corresponding to different blocks may also occur in a different order than disclosed in the description; sometimes there is no specific order between different operations or steps. For example, two consecutive operations or steps may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. Each block in a block diagram and / or flowchart, and combinations of blocks in a block diagram and / or flowchart, can be implemented using a dedicated hardware-based system that performs the specified function or action, or using a combination of dedicated hardware and computer instructions.

[0078] It will be apparent to those skilled in the art that this application is not limited to the details of the exemplary embodiments described above, and that this application can be implemented in other specific forms without departing from its essential characteristics. Therefore, the embodiments described above should be considered exemplary and non-limiting in all respects; modifications to the technical solutions described in the foregoing embodiments, or equivalent substitutions of some technical features, without causing the essence of the corresponding technical solutions to deviate from the scope of the technical solutions in the embodiments of this application, should all be included within the protection scope of this application.

Claims

1. An automatic cooling method for acid chlorination in the preparation of insecticides, characterized in that, The method includes the following steps: For each control moment in the acid chlorination process, the pressure inside the vessel, the temperature inside the vessel, and the chlorine flow rate at each moment within the preset sampling period are obtained; The numerical distribution of the temperature difference between adjacent moments in the vessel within the sampling period is analyzed. All moments are filtered based on a threshold segmentation algorithm to obtain the proportion of abnormal mutation time series. The dispersion of all temperature data within the sampling period is analyzed, and combined with the proportion of abnormal mutation time series, the continuous temperature mutation value of the sampling period is obtained. The in-vessel temperature at each moment within the sampling period is compared with a preset in-vessel evaporation threshold to filter high-temperature values. Based on the in-vessel pressure at all moments within the sampling period, the in-vessel pressure at the next moment is predicted. The ratio between the predicted pressure value and the average in-vessel pressure at all moments within the sampling period is calculated and recorded as the first ratio. The difference between each high-temperature value in the in-vessel within the sampling period and the in-vessel evaporation threshold is calculated and divided by the in-vessel evaporation threshold to obtain the second ratio. The second ratios of all high-temperature values ​​in the in-vessel within the sampling period are accumulated and multiplied by the first ratio to obtain the dichloroethane evaporation weight of the sampling period. This weight is then multiplied by the continuous temperature change value of the sampling period to obtain the chlorination superheat of the sampling period. A trend verification algorithm is used to normalize the obtained trend statistics for chlorine flow rate at all times within the sampling period to obtain the chlorine trend evaluation value. The normalized value obtained by multiplying the chlorine trend evaluation value by the chlorination superheat is used as the cooling regulation intensity within the sampling period. If the value of the cooling regulation intensity within the sampling period is less than the preset cooling threshold, the flow rate of the circulating cooling water in the chlorination reactor is controlled; otherwise, the flow rate of the circulating cooling water and the chlorine flow rate are controlled. The specific method for controlling the circulating cooling water flow rate and chlorine flow rate is as follows: Calculate the average circulating cooling water flow rate and the average chlorine flow rate at all times within the sampling period; calculate the sum of the natural number 1 and the cooling regulation force, and use the product of the sum and the average circulating cooling water flow rate as the circulating cooling water flow rate at the corresponding control time; use the product of the sum and the average chlorine flow rate as the chlorine flow rate at the corresponding control time.

2. The automatic cooling method for acid chlorination in the preparation of insecticides as described in claim 1, characterized in that, The percentage of anomalous mutation time sequences obtained is specifically as follows: Calculate the absolute value of the temperature difference between the inside of the vessel at each moment within the sampling period and the previous moment, and use it as the temperature change amplitude at each moment; A threshold segmentation algorithm is used to segment all temperature change amplitudes within the sampling period to obtain a segmentation threshold. The time when the temperature change amplitude is greater than the segmentation threshold is recorded as the abnormal change time series value. Calculate the percentage of abnormal mutation time series values ​​in all time periods within the sampling period to obtain the percentage of abnormal mutation time series values ​​in the sampling period.

3. The automatic cooling method for acid chlorination in the preparation of insecticides as described in claim 1, characterized in that, The temperature fluctuation value for the sampling period is specifically the product of the standard deviation of all temperature data within the sampling period and the proportion of the abnormal fluctuation time sequence.

4. The automatic cooling method for acid chlorination in the preparation of insecticides as described in claim 1, characterized in that, The high temperature value inside the vessel is specifically the temperature inside the vessel that is greater than or equal to the evaporation threshold within the vessel during the sampling period.

5. An automatic cooling system for acid chlorination in the preparation of insecticides, comprising a memory, a processor, and a computer program stored in the memory and running on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the method as described in any one of claims 1-4.

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