Safety control method and system in preparation process of methyl ethyl carbonate

Abstract

The invention relates to a safety control method and system in a methyl ethyl carbonate preparation process, dimethyl carbonate is input into a dimethyl carbonate purification tower, air pressure in the purification tower is detected, and air pressure adjustment is carried out when an air pressure detection value is not in a preset air pressure range; detecting the purity of the output dimethyl carbonate; the output dimethyl carbonate, a catalyst sodium methoxide / methanol solution and absolute ethyl alcohol are input into a raw material mixing unit according to a specified proportion to be mixed to meet the uniformity requirement, air pressure and temperature detection is conducted in an EMC reaction tower, and if corresponding requirements are not met, air pressure or temperature adjustment is conducted; tower bottoms in the EAC reaction tower are conveyed to a gas-phase substance treated in the waste catalyst concentration tank to be treated by an EMC light component removal tower; the temperature and the air pressure in the EAC light component removal tower are detected, when the air pressure of the EMC reaction tower is not in a preset range, the air pressure or the temperature is adjusted, and an EMC finished product is obtained after cooling treatment, so that the safe and stable production and preparation process of the ethyl methyl carbonate is realized.

Description

Technical Field

[0001] The invention belongs to the technical field of ethyl methyl carbonate production, and in particular relates to a safety control method and system in the preparation process of ethyl methyl carbonate. Background Art

[0002] Ethyl methyl carbonate (EMC) is a colorless transparent liquid with the molecular formula C4H8O3. It is insoluble in water and is mainly used as a solvent for organic synthesis and lithium-ion battery electrolytes. It can cause combustion and explosion when exposed to high heat, open flames or violent impacts. It is a flammable chemical.

[0003] In the production process of ethyl methyl carbonate, industrial-grade dimethyl carbonate is first pumped into an electronic-grade DMC purification tower for purification at 50-55°C and -0.06-0.08MPa. The purified dimethyl carbonate, catalyst sodium methoxide / methanol solution and anhydrous ethanol from the tank area are then sent to the EMC reaction tower in corresponding proportions for transesterification under specified pressure and temperature conditions. Part of the dimethyl carbonate is converted into ethyl methyl carbonate, and the EMC finished product is obtained through subsequent light removal and cooling treatment.

[0004] In the production process of ethyl methyl carbonate, it is necessary to control the temperature and pressure of each production equipment, such as the dimethyl carbonate purification tower, the EMC reaction tower and the EAC light removal tower, so as to obtain dimethyl carbonate that meets the purity requirements or to allow the reaction to proceed fully or to achieve full light removal. At the same time, in the production process of ethyl methyl carbonate, it is also necessary to ensure that each production equipment will not leak. If there is leakage of raw materials or finished products such as dimethyl carbonate or ethyl methyl carbonate, it will cause serious safety hazards.

[0005] Therefore, how to carry out safety control in the production and preparation process of ethyl methyl carbonate to ensure that the entire production and preparation process of ethyl methyl carbonate is carried out safely and stably is a technical problem that urgently needs to be solved. Summary of the invention

[0006] The object of the present invention is to provide a safety control method and system in the preparation process of ethyl methyl carbonate, which are used to perform safety control in the production process of ethyl methyl carbonate and ensure that the entire production process of ethyl methyl carbonate is carried out safely and stably.

[0007] In order to solve the above technical problems, the technical solution adopted by the present invention is as follows:

[0008] A safety control method in a preparation process of ethyl methyl carbonate comprises the following steps:

[0009] S1: inputting industrial-grade dimethyl carbonate into a dimethyl carbonate purification tower, detecting the air pressure in the dimethyl carbonate purification tower by an air pressure detection unit, and when the air pressure detection value is not within a preset air pressure range, adjusting the air pressure in the dimethyl carbonate purification tower by an air pressure regulating unit until the air pressure detection value is within the preset air pressure range;

[0010] S2: After being purified by the dimethyl carbonate purification tower, the purity of the output dimethyl carbonate is detected by the purity detection unit to determine whether the purity of the output dimethyl carbonate is within a preset purity range. If so, step S3 is executed; if not, the output dimethyl carbonate is returned to the dimethyl carbonate purification tower for re-purification;

[0011] S3: input the output dimethyl carbonate, catalyst sodium methoxide / methanol solution and anhydrous ethanol into the raw material mixing unit in a specified ratio for mixing, and perform uniformity detection on the mixed raw materials through the uniformity detection unit, and determine whether the uniformity detection result of the mixed raw materials is within the preset uniformity range. If so, execute step S4; if not, continue to mix the raw materials until the uniformity detection result is within the preset uniformity range;

[0012] S4: sending uniform raw materials into the EMC reaction tower, detecting the air pressure in the EMC reaction tower, and adjusting the air pressure through the air pressure regulating unit when the air pressure in the EMC reaction tower is not within the preset air pressure range, and detecting the temperature in the EMC reaction tower through the temperature detection device, and adjusting the temperature through the temperature regulating unit when the temperature is not within the preset temperature range;

[0013] S6: The bottom liquid in the EAC reaction tower is transported to a waste catalyst concentration tank for treatment to obtain liquid phase material and gas phase material, the liquid phase material is dried, and the gas phase material is transported to an EMC light removal tower for treatment;

[0014] S7: Detect the temperature and air pressure in the EAC light removal tower. When the air pressure in the EMC reaction tower is not within the preset air pressure range, the air pressure is adjusted by the air pressure regulating unit. When the temperature is not within the preset temperature range, the temperature is adjusted by the temperature regulating unit.

[0015] S8: The bottom liquid in the EAC light removal tower is sent to the EMC product tower, and after being cooled by the cooler, the temperature in the cooler is detected. When the temperature of the cooler is not within the preset range, the temperature is adjusted by the temperature adjustment unit, and the cooled object is transported to the EMC finished product tank to obtain the EMC finished product.

[0016] Preferably, at the same time as step S1, the temperature in the dimethyl carbonate purification tower is detected by a temperature detection unit, and it is determined whether the temperature detection value is within a preset temperature range. If the temperature detection value is not within the preset temperature range, the temperature in the dimethyl carbonate purification tower is adjusted by a temperature adjustment unit.

[0017] Preferably, a leakage detection process is also included, which is as follows:

[0018] A leakage detection device is arranged at a designated position of each production equipment, and leakage detection is performed during the entire preparation process of ethyl methyl carbonate. Ultraviolet light is emitted to the designated position by the leakage detection device. When dimethyl carbonate or ethyl methyl carbonate leaks, the volatilized dimethyl carbonate or ethyl methyl carbonate is excited by ultraviolet light in the ionization chamber of the leakage detection device. The excited dimethyl carbonate or ethyl methyl carbonate molecules are ionized into positively charged and negatively charged particles. The charged particles collide with the electrode plate to form a detectable weak current. The weak current is amplified by the amplification circuit. The corresponding leakage degree and leakage position are displayed on the display module according to the detected current size, and an early warning is performed through the early warning module.

[0019] Preferably, the amplifying circuit comprises a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a first capacitor and a differential amplifier;

[0020] One end of the first resistor is connected to the positive electrode of the current output, and the other end is connected to the negative electrode of the current output; one end of the second resistor is connected to the first resistor, and the other end is respectively connected to the inverting input terminal of the differential amplifier, the first capacitor and the fourth resistor; the other end of the fourth resistor and the other end of the first capacitor are both grounded through the sixth resistor and connected to the output terminal of the amplified current;

[0021] One end of the third resistor is connected to the first resistor, and the other end is respectively connected to the in-phase input terminal of the differential amplifier and the fifth resistor. The positive pole of the power supply of the differential amplifier is connected to a 5V power supply, and the negative pole of the power supply is grounded.

[0022] Preferably, each temperature regulating unit and each pressure regulating unit of the dimethyl carbonate purification tower, EMC reaction tower, and EMC light-removal tower are also deployed with a temperature and pressure prediction model. The historical purification time data and the corresponding temperature and pressure data in the purification tower, the historical EMC reaction time data and the corresponding temperature and pressure data in the EMC reaction tower, the historical light-removal time data in the EMC light-removal tower and the corresponding temperature and pressure data in the EMC light-removal tower are obtained by the data acquisition module to construct a historical data set, and the historical data set is annotated, and the annotated historical data set is input into the temperature and pressure prediction model to train the model.

[0023] Preferably, in the dimethyl carbonate purification stage, the purification time data of the dimethyl carbonate purification tower is obtained through the data acquisition module, and the purification time data is input into the temperature and pressure prediction model, and the temperature and pressure prediction model predicts the temperature and pressure corresponding to the purification time data, draws a relationship diagram between the temperature and pressure and the purification time change, and generates a relationship diagram between the temperature and pressure adjustment amount and the purification time;

[0024] In the EMC reaction stage, the reaction time data of the EMC reaction tower is obtained through the data acquisition module, and the reaction time data is input into the temperature and pressure prediction model. The temperature and pressure prediction model predicts the temperature and pressure corresponding to the reaction time data, draws a relationship diagram between the temperature and pressure and the reaction time change, and generates a relationship diagram between the temperature and pressure adjustment amount and the reaction time;

[0025] In the EMC delightening stage, the delightening time data of the EMC delightening tower is obtained through the data acquisition module, and the delightening time data is input into the temperature and pressure prediction model. The temperature and pressure prediction model predicts the temperature and pressure corresponding to the delightening time data, draws a relationship diagram between the temperature and pressure and the delightening time change, and generates a relationship diagram between the temperature and pressure adjustment amount and the delightening time;

[0026] The temperature regulating unit and the air pressure regulating unit directly obtain the temperature and air pressure regulating amounts that change with time in each stage through the temperature and air pressure regulating amount and purification time relationship diagram, the temperature and air pressure regulating amount and reaction time relationship diagram, and the temperature and air pressure regulating amount and light removal time relationship diagram, and realize early adjustment of the temperature and air pressure based on the temperature and air pressure regulating amounts, so that the specified temperature and air pressure can be reached at the corresponding time point.

[0027] Preferably, in the process of the temperature regulating unit and the air pressure regulating unit adjusting the temperature and air pressure based on the temperature and air pressure adjustment amount, the temperature detection unit and the air pressure detection unit respectively detect the temperature and air pressure of the corresponding equipment in real time, and judge whether the prediction result of the temperature and air pressure prediction model is accurate based on the real-time detection result; if inaccurate, the inaccurate temperature or air pressure and the corresponding time point are fed back to the temperature regulating unit and the air pressure regulating unit to adjust the temperature and air pressure adjustment amount.

[0028] Preferably, the temperature and air pressure prediction model is a neural network model, including an input layer, a hidden layer and an output layer. The input layer is a three-channel model, which is used to input temperature data, air pressure data and corresponding time data respectively. The corresponding time data is purification time data, EMC reaction time data and EMC de-lightening time data. The hidden layer has multiple layers for capturing the relationship between the input temperature data and air pressure data and the corresponding time data. The output layer is used to output the predicted temperature data and air pressure data.

[0029] Preferably, the output calculation formula of the hidden layer is as follows:

[0030] Z k =f(w k1 *X1+w k2 *X2+···+w ki *X i +w kn *X n );

[0031] Among them, Z k is the output of the hidden layer, f is a nonlinear function, w k1 is the weight between the first node of the input layer and the kth node of the hidden layer, w k2 is the weight between the second node of the input layer and the kth node of the hidden layer, w ki is the weight between the i-th node in the input layer and the k-th node in the hidden layer, w kn is the weight between the nth node in the input layer and the kth node in the hidden layer, X1 is the input of the first node in the input layer, X2 is the input of the second node in the input layer, and X i is the input of the i-th node in the input layer, X n is the input of the nth node in the input layer.

[0032] In a second aspect, a safety control system in the preparation process of ethyl methyl carbonate is provided, which is used to implement any one of the safety control methods in the preparation process of ethyl methyl carbonate, including a data acquisition module, a purity detection unit, a uniformity detection unit, an air pressure adjustment unit, a temperature adjustment unit, and a temperature and air pressure prediction model, wherein the data acquisition module is provided with a plurality of units, which are respectively arranged in a dimethyl carbonate purification tower, an EMC reaction tower, and an EAC light removal tower, the data acquisition module includes an air pressure detection unit and a temperature detection unit, the purity detection unit is arranged at the output end of the dimethyl carbonate purification tower, the uniformity detection unit is arranged inside a raw material mixing unit, the air pressure adjustment unit and the temperature adjustment unit are connected to the dimethyl carbonate purification tower, the EMC reaction tower, and the EAC light removal tower, and the temperature and air pressure prediction model is connected to the data acquisition module, the air pressure adjustment unit, and the temperature adjustment unit;

[0033] The data acquisition module is used to acquire various historical data and real-time data in the dimethyl carbonate purification tower, the EMC reaction tower and the EAC lightness removal tower;

[0034] The uniformity detection unit is used to detect the uniformity of the raw materials in the raw material mixing unit;

[0035] The gas pressure regulating unit is used to regulate the gas pressure in the dimethyl carbonate purification tower, the EMC reaction tower and the EAC lightness removal tower;

[0036] The temperature regulating unit is used to regulate the temperature in the dimethyl carbonate purification tower, the EMC reaction tower and the EAC lightness removal tower;

[0037] The temperature and pressure prediction model is used for the purification time data of the dimethyl carbonate purification tower, the reaction time data of the EMC reaction tower and the light removal time data of the EMC light removal tower to predict the temperature and pressure of the dimethyl carbonate purification tower, the EMC reaction tower and the EMC light removal tower at the corresponding time.

[0038] The beneficial effects of the present invention include:

[0039] The invention provides a safety control method and system for the preparation process of ethyl methyl carbonate. The method comprises the following steps: inputting dimethyl carbonate into a dimethyl carbonate purification tower, detecting the air pressure in the purification tower, and adjusting the air pressure when the air pressure detection value is not within a preset air pressure range; detecting the purity of the output dimethyl carbonate; inputting the output dimethyl carbonate, a catalyst sodium methoxide / methanol solution and anhydrous ethanol into a raw material mixing unit according to a specified ratio to mix them to meet the uniformity requirement; detecting the air pressure and temperature in an EMC reaction tower, and adjusting the air pressure or temperature if the corresponding requirements are not met; conveying the tower bottom liquid in the EAC reaction tower to a gas phase substance for treatment in a waste catalyst concentration tank to an EMC light-removal tower for treatment; detecting the temperature and air pressure in the EAC light-removal tower, and adjusting the air pressure or temperature when the air pressure in the EMC reaction tower is not within a preset range, and obtaining the EMC finished product after cooling, thereby realizing the safe and stable production and preparation process of ethyl methyl carbonate.

[0040] First, by arranging a leakage detection device at a designated position of each production equipment, leakage detection is performed throughout the entire preparation process of ethyl methyl carbonate. The leakage detection device emits ultraviolet light to the designated position. When dimethyl carbonate or ethyl methyl carbonate leaks, the volatilized dimethyl carbonate or ethyl methyl carbonate is excited by ultraviolet light in the ionization chamber of the leakage detection device. The excited dimethyl carbonate or ethyl methyl carbonate molecules are ionized into positively charged and negatively charged particles. The charged particles collide with the electrode plate to form a detectable weak current. The weak current is amplified by the amplifier circuit, and the size of the detected current is used to display the degree of leakage, thereby achieving strict leakage monitoring. After the leakage occurs, it can be handled in time to ensure the leakage safety of the entire production and preparation process.

[0041] Second, by setting an amplification circuit in the leakage detection device, including a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a first capacitor and a differential amplifier; one end of the first resistor is connected to the positive electrode of the current output, and the other end is connected to the negative electrode of the current output; one end of the second resistor is connected to the first resistor, and the other end is respectively connected to the inverting input end of the differential amplifier, the first capacitor and the fourth resistor; the other end of the fourth resistor and the other end of the first capacitor are both grounded through the sixth resistor and connected to the output end of the amplified current; one end of the third resistor is connected to the first resistor, and the other end is respectively connected to the non-inverting input end of the differential amplifier and the fifth resistor. The amplification process of weak current is realized, so that micro leakage can be discovered, and it is avoided that the leakage is not discovered until the amount becomes large, causing a large safety hazard.

[0042] Third, by deploying a temperature and pressure prediction model, the data acquisition module obtains relevant historical data and annotates it, inputs the annotated historical data set into the temperature and pressure prediction model to train the model, and predicts the temperature and pressure based on the purification time data of the dimethyl carbonate purification tower, the reaction time data of the EMC reaction tower, and the light removal time data of the EMC light removal tower, so that the subsequent temperature and pressure can be adjusted in advance. Since the temperature and pressure adjustment are all delayed, it is not possible to instantly reach the preset temperature and pressure when adjusting the temperature and pressure. Therefore, by predicting the temperature and pressure through the temperature and pressure prediction model, the temperature and pressure can be adjusted in advance so that the preset temperature and pressure can be reached at the specified time.

[0043] Fourth, the temperature and air pressure prediction model sets up an input layer, a hidden layer and an output layer. The input layer has three channels, which are used to input temperature data, air pressure data and corresponding time data respectively, so that the subsequent hidden layer can extract the characteristic relationship between temperature data, air pressure data and corresponding time data. The hidden layer has multiple layers, which are used to capture the relationship between the input temperature data and air pressure data and the corresponding time data. The output layer is used to output the predicted temperature data and air pressure data, and the detailed output calculation formula Z of the hidden layer is set. k =f(w k1 *X1+w k2 *X2+···+w ki *X i +w kn *X n ), so that accurate feature capture can be performed through the hidden layer, and then accurate temperature and pressure prediction results can be output. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 The present invention is a schematic flow chart of the safety control method in the preparation process of ethyl methyl carbonate.

[0045] Figure 2It is a schematic diagram of the circuit structure of the amplifier circuit of the present invention.

[0046] Description of the drawings: R1 is a first resistor, R2 is a second resistor, R3 is a third resistor, R4 is a fourth resistor, R5 is a fifth resistor, R6 is a sixth resistor, C1 is a first capacitor, and DA is a differential amplifier. DETAILED DESCRIPTION

[0047] The following is combined with Figure 1-2 The present invention is further described in detail:

[0048] Example 1

[0049] See attached Figure 1 As shown, a safety control method in the preparation process of ethyl methyl carbonate comprises the following steps:

[0050] S1: Input industrial-grade dimethyl carbonate into a dimethyl carbonate purification tower, and detect the air pressure in the dimethyl carbonate purification tower by an air pressure detection unit. When the air pressure detection value is not within the preset air pressure range, the air pressure in the dimethyl carbonate purification tower is adjusted by an air pressure regulating unit until the air pressure detection value is within the preset air pressure range. The industrial-grade dimethyl carbonate is purchased dimethyl carbonate, and its purity does not meet the requirements for EMC reaction, so it needs to be transported to a dimethyl carbonate purification tower for purification. The dimethyl carbonate purification tower, i.e., the DMC purification tower, needs to be treated at 50 to 55°C and -0.06 to 0.08MPa. Since it is necessary to treat under these temperature and air pressure conditions, the air pressure and temperature need to be adjusted to within this range to ensure that the purification process is carried out efficiently.

[0051] The top gas of the purification tower is the light component, which is sent to the industrial-grade DMC intermediate tank after condensation as the raw material for EMC / DEC synthesis; the heavy component in the bottom of the tower is used as the raw material for EMC / DEC synthesis; the liquid material extracted from the side line of the DMC purification tower is cooled by the cooler and sent to the electronic-grade DMC product tank. The non-condensable gas (G1) generated during the condensation of the top gas of the DMC purification tower is collected and sent to the tail gas treatment system for incineration in the RTO furnace.

[0052] S2: After being purified by a dimethyl carbonate purification tower, the dimethyl carbonate is outputted, and the purity of the outputted dimethyl carbonate is detected by the purity detection unit to determine whether the purity of the outputted dimethyl carbonate is within a preset purity range. If so, step S3 is executed; if not, the outputted dimethyl carbonate is returned to the dimethyl carbonate purification tower for re-purification; in order to ensure that the purity meets the EMC reaction requirements, the purity needs to be detected. If it does not meet the corresponding purity requirements, it is returned to the purification tower for re-purification, which effectively ensures the purity of the raw materials during the subsequent EMC reaction, so that the EMC reaction tower can fully and efficiently react, while ensuring the safety of the reaction process.

[0053] S3: The output dimethyl carbonate, catalyst sodium methoxide / methanol solution and anhydrous ethanol are input into the raw material mixing unit in a specified ratio for mixing, and the uniformity detection unit is used to detect the uniformity of the mixed raw materials, and it is determined whether the uniformity detection result of the mixed raw materials is within the preset uniformity interval. If so, step S4 is executed; if not, the raw material mixing is continued until the uniformity detection result is within the preset uniformity interval. The process of uniformity detection is to ensure that the raw materials are fully mixed, promote the efficient reaction process in the subsequent reaction tower, and shorten the reaction time.

[0054] Catalyst sodium methoxide / methanol solution, industrial-grade DMC and anhydrous ethanol from the tank area are pumped into the raw material mixing tank in a ratio of 0.0024:1:0.588 for mixing.

[0055] S4: uniform raw materials are fed into the EMC reaction tower, and the air pressure in the EMC reaction tower is detected. When the air pressure in the EMC reaction tower is not within the preset air pressure range, the air pressure is adjusted by the air pressure regulating unit, and the temperature in the EMC reaction tower is detected by the temperature detection device. When the temperature is not within the preset temperature range, the temperature is adjusted by the temperature regulating unit. Through the temperature and air pressure adjustment process, the air pressure in the reaction tower meets the corresponding reaction conditions, and the reaction can proceed normally.

[0056] The mixed catalyst sodium methoxide / methanol solution, industrial-grade DMC and anhydrous ethanol from the tank area are pumped into the EMC reaction tower for reaction. Under normal pressure and 100-110°C, dimethyl carbonate and ethanol undergo ester exchange reaction in the reactor, and part of dimethyl carbonate is converted into ethyl methyl carbonate.

[0057] S6: The bottom liquid in the EAC reaction tower is transported to a waste catalyst concentration tank for treatment to obtain liquid phase material and gas phase material, the liquid phase material is dried, and the gas phase material is transported to an EMC light removal tower for treatment;

[0058] S7: Detect the temperature and air pressure in the EAC light removal tower. When the air pressure in the EMC reaction tower is not within the preset air pressure range, the air pressure is adjusted by the air pressure regulating unit. When the temperature is not within the preset temperature range, the temperature is adjusted by the temperature regulating unit.

[0059] S8: The bottom liquid in the EAC light removal tower is sent to the EMC product tower, and after being cooled by the cooler, the temperature in the cooler is detected. When the temperature of the cooler is not within the preset range, the temperature is adjusted by the temperature adjustment unit, and the cooled object is transported to the EMC finished product tank to obtain the EMC finished product.

[0060] In this embodiment, at the same time as step S1, the temperature in the dimethyl carbonate purification tower is detected by a temperature detection unit, and it is determined whether the temperature detection value is within a preset temperature range. If the temperature detection value is not within the preset temperature range, the temperature in the dimethyl carbonate purification tower is adjusted by a temperature adjustment unit.

[0061] In the EMC reaction tower, ethyl methyl carbonate and ethanol undergo an ester exchange reaction to generate diethyl carbonate, and methanol as a byproduct is generated during the reaction. In the EMC reaction tower, while ethyl methyl carbonate, diethyl carbonate and byproduct methanol are generated, methanol is separated from ethyl methyl carbonate and diethyl carbonate. Methanol and part of the raw material DMC are distilled from the top of the tower in the form of an azeotrope and pumped into the pressure tower. The bottom liquid of the EMC reaction tower is excess dimethyl carbonate (all ethanol participates in the reaction) and the generated ethyl methyl carbonate and diethyl carbonate, which are sent to the waste catalyst concentration tank. The azeotrope distilled from the top of the pressure tower enters the atmospheric pressure tower, and the bottom liquid is mainly the recovered DMC, which returns to the raw material tank. The azeotrope distilled from the top of the atmospheric pressure tower is returned to the pressure tower, and the bottom liquid of the atmospheric pressure tower is the methanol byproduct.

[0062] After the materials in the concentration tank evaporate, the gaseous materials enter the EMC light removal tower, and the liquid phase is mainly the catalyst sodium methoxide / methanol solution, which is dried by the vacuum dryer under steam heating and then recycled. The dry waste gas (G2) generated during the drying process is collected by the vacuum system and sent to the RTO incinerator for incineration; after multiple reuse and deactivation, the waste catalyst (S1) is outsourced for hazardous waste disposal.

[0063] The gaseous material entering the EMC light removal tower is heated to 110-120°C by steam under the condition of 10-20KPa. The gaseous phase (mainly DMC) comes out from the top of the tower and is condensed to recover DMC. The non-condensable gas (G3) produced in the condensation process is collected and sent to the RTO incinerator for treatment. The recovered DMC is reused in the EMC reaction tower, and the bottom liquid is pumped into the EMC product tower for EMC purification under the conditions of 80-85°C and -75--85KPa. The light components at the top of the EMC product tower are returned to the EMC light removal tower, and the bottom liquid is sent to the DEC purification process. The liquid material extracted from the side line is cooled by the cooler and sent to the electronic grade EMC product tank.

[0064] Example 2

[0065] On the basis of Example 1, a leakage detection process is also included, which is as follows:

[0066] A leakage detection device is arranged at a designated position of each production equipment, and leakage detection is performed during the entire preparation process of ethyl methyl carbonate. Ultraviolet light is emitted to the designated position by the leakage detection device. When dimethyl carbonate or ethyl methyl carbonate leaks, the volatilized dimethyl carbonate or ethyl methyl carbonate is excited by ultraviolet light in the ionization chamber of the leakage detection device. The excited dimethyl carbonate or ethyl methyl carbonate molecules are ionized into positively charged and negatively charged particles. The charged particles collide with the electrode plate to form a detectable weak current. The weak current is amplified by the amplification circuit. The corresponding leakage degree and leakage position are displayed on the display module according to the detected current size, and an early warning is performed through the early warning module. By arranging a leakage detection device at a designated position of each production equipment, leakage detection is performed during the entire preparation process of ethyl methyl carbonate. The leakage detection device emits ultraviolet light to the designated position. When dimethyl carbonate or ethyl methyl carbonate leaks, the volatilized dimethyl carbonate or ethyl methyl carbonate is excited by ultraviolet light in the ionization chamber of the leakage detection device. The excited dimethyl carbonate or ethyl methyl carbonate molecules are ionized into positively charged and negatively charged particles. The charged particles collide with the electrode plate to form a detectable weak current. The weak current is amplified by an amplifier circuit, and the magnitude of the detected current is displayed to show the degree of leakage, thereby achieving strict leakage monitoring. In the event of leakage, the corresponding leakage information including the degree of leakage and the leakage location information is transmitted to the early warning module for early warning processing, so that the safety management personnel can handle the leakage in time after the corresponding equipment leaks, thereby ensuring the leakage safety of the entire production and preparation process.

[0067] In this embodiment, see Figure 2 As shown, the amplification circuit includes a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a first capacitor C1 and a differential amplifier DA; one end of the first resistor R1 is connected to the positive electrode of the current output, and the other end is connected to the negative electrode of the current output; one end of the second resistor R2 is connected to the first resistor R1, and the other end is respectively connected to the inverting input end of the differential amplifier DA, the first capacitor C1 and the fourth resistor R4; the other end of the fourth resistor R4 and the other end of the first capacitor C1 are both grounded through the sixth resistor R6, and connected to the output end of the amplified current; one end of the third resistor R3 is connected to the first resistor R1, and the other end is respectively connected to the in-phase input end of the differential amplifier DA and the fifth resistor R5; the positive electrode of the power supply of the differential amplifier DA is connected to a 5V power supply, and the negative electrode of the power supply is grounded. The amplification process of weak current is realized, so that micro leakage can be discovered, and it is avoided that the leakage is discovered only after it becomes large, causing a large safety hazard.

[0068] Example 3

[0069] On the basis of Example 1 or Example 2, a temperature and pressure prediction model is also deployed in each temperature regulating unit and each pressure regulating unit of the dimethyl carbonate purification tower, the EMC reaction tower, and the EMC light-removal tower. The historical purification time data and the corresponding temperature and pressure data in the purification tower, the historical EMC reaction time data and the corresponding temperature and pressure data in the EMC reaction tower, the historical light-removal time data in the EMC light-removal tower and the corresponding temperature and pressure data in the EMC light-removal tower are obtained by the data acquisition module to construct a historical data set, and the historical data set is annotated. The annotated historical data set is input into the temperature and pressure prediction model to train the model.

[0070] During the dimethyl carbonate purification stage, the purification time data of the dimethyl carbonate purification tower is obtained through the data acquisition module, and the purification time data is input into the temperature and pressure prediction model. The temperature and pressure prediction model predicts the temperature and pressure corresponding to the purification time data, draws a relationship graph between the temperature and pressure and the purification time change, and generates a relationship graph between the temperature and pressure adjustment amount and the purification time.

[0071] In the EMC reaction stage, the reaction time data of the EMC reaction tower is obtained through the data acquisition module, and the reaction time data is input into the temperature and pressure prediction model. The temperature and pressure prediction model predicts the temperature and pressure corresponding to the reaction time data, draws a relationship diagram between the temperature and pressure and the reaction time change, and generates a relationship diagram between the temperature and pressure adjustment amount and the reaction time. In the EMC light removal stage, the light removal time data of the EMC light removal tower is obtained through the data acquisition module, and the light removal time data is input into the temperature and pressure prediction model. The temperature and pressure prediction model predicts the temperature and pressure corresponding to the light removal time data, draws a relationship diagram between the temperature and pressure and the light removal time change, and generates a relationship diagram between the temperature and pressure adjustment amount and the light removal time.

[0072] The temperature regulating unit and the air pressure regulating unit directly obtain the temperature and air pressure regulating amounts that change with time in each stage through the temperature and air pressure regulating amount and purification time relationship diagram, the temperature and air pressure regulating amount and reaction time relationship diagram, and the temperature and air pressure regulating amount and light removal time relationship diagram, and realize early adjustment of the temperature and air pressure based on the temperature and air pressure regulating amounts, so that the specified temperature and air pressure can be reached at the corresponding time point.

[0073] By deploying a temperature and pressure prediction model, the data acquisition module obtains relevant historical data and annotates it, inputs the annotated historical data set into the temperature and pressure prediction model to train the model, and predicts the temperature and pressure based on the purification time data of the dimethyl carbonate purification tower, the reaction time data of the EMC reaction tower, and the light removal time data of the EMC light removal tower, so that the subsequent temperature and pressure can be adjusted in advance. Since the adjustment of temperature and pressure is delayed, it is not possible to instantly reach the preset temperature and pressure when adjusting the temperature and pressure. Therefore, by predicting the temperature and pressure through the temperature and pressure prediction model, the temperature and pressure can be adjusted in advance so that the preset temperature and pressure can be reached at the specified time.

[0074] In this embodiment, in the process of the temperature adjustment unit and the air pressure adjustment unit adjusting the temperature and air pressure based on the temperature and air pressure adjustment amount, the temperature detection unit and the air pressure detection unit respectively detect the temperature and air pressure of the corresponding equipment in real time, and judge whether the prediction result of the temperature and air pressure prediction model is accurate based on the real-time detection result. If it is inaccurate, the inaccurate temperature or air pressure and the corresponding time point are fed back to the temperature adjustment unit and the air pressure adjustment unit to adjust the temperature and air pressure adjustment amount.

[0075] Example 4

[0076] On the basis of Example 1 or Example 2 or Example 3, the temperature and air pressure prediction model is a neural network model, including an input layer, a hidden layer and an output layer. The input layer is a three-channel model, which is used to input temperature data, air pressure data and corresponding time data respectively. The corresponding time data is purification time data, EMC reaction time data and EMC de-lightening time data. The hidden layer has multiple layers, which are used to capture the relationship between the input temperature data and air pressure data and the corresponding time data. The output layer is used to output the predicted temperature data and air pressure data. The temperature and air pressure prediction model is provided with an input layer, a hidden layer and an output layer. The input layer is a three-channel model, which is used to input temperature data, air pressure data and corresponding time data respectively, so as to facilitate the subsequent hidden layer to extract the characteristic relationship between the temperature data, air pressure data and the corresponding time data.

[0077] In this embodiment, the output calculation formula of the hidden layer is as follows:

[0078] Z k =f(w k1 *X1+w k2 *X2+···+w ki *X i +w kn *X n );

[0079] Among them, Z kis the output of the hidden layer, f is a nonlinear function, w k1 is the weight between the first node of the input layer and the kth node of the hidden layer, w k2 is the weight between the second node of the input layer and the kth node of the hidden layer, w ki is the weight between the i-th node in the input layer and the k-th node in the hidden layer, w kn is the weight between the nth node in the input layer and the kth node in the hidden layer, X1 is the input of the first node in the input layer, X2 is the input of the second node in the input layer, and X i is the input of the i-th node in the input layer, X n is the input of the nth node in the input layer.

[0080] The hidden layer is set up with multiple layers to accurately capture the relationship between the input temperature data and air pressure data and the corresponding time data. The output layer is used to output the predicted temperature data and air pressure data, and set the detailed output calculation formula Z of the hidden layer. k =f(w k1 *X1+w k2 *X2+···+w ki *X i +w kn *X n ), so that accurate feature capture can be performed through the hidden layer, and then accurate temperature and pressure prediction results can be output.

[0081] In addition to extracting the relationship features between the temperature data and air pressure data and the corresponding time data, the hidden layer also simultaneously performs the process of data dimensionality reduction and extraction of feature information classification. Through the processing of the hidden layer, the complexity of the data is reduced, and the neural network can process the input data more efficiently. The hidden layer can better understand and process the data by automatically learning the inherent laws and characteristics of the input data, thereby achieving accurate prediction of temperature and air pressure.

[0082] A safety control system in the preparation process of ethyl methyl carbonate is used to implement any one of the safety control methods in the preparation process of ethyl methyl carbonate, comprising a data acquisition module, a purity detection unit, a uniformity detection unit, an air pressure adjustment unit, a temperature adjustment unit, and a temperature and air pressure prediction model. The data acquisition module is provided with a plurality of units, which are respectively arranged in a dimethyl carbonate purification tower, an EMC reaction tower and an EAC light removal tower. The data acquisition module comprises an air pressure detection unit and a temperature detection unit. The purity detection unit is arranged at the output end of the dimethyl carbonate purification tower, the uniformity detection unit is arranged inside a raw material mixing unit, the air pressure adjustment unit and the temperature adjustment unit are connected to the dimethyl carbonate purification tower, the EMC reaction tower and the EAC light removal tower, and the temperature and air pressure prediction model is connected to the data acquisition module, the air pressure adjustment unit and the temperature adjustment unit.

[0083] The data acquisition module is used to acquire various historical data and real-time data in the dimethyl carbonate purification tower, EMC reaction tower and EAC lightness removal tower; the uniformity detection unit is used to detect the uniformity of the raw materials in the raw material mixing unit; the air pressure regulating unit is used to regulate the air pressure in the dimethyl carbonate purification tower, EMC reaction tower and EAC lightness removal tower; the temperature regulating unit is used to regulate the temperature in the dimethyl carbonate purification tower, EMC reaction tower and EAC lightness removal tower; the temperature and air pressure prediction model is used to predict the temperature and air pressure of the dimethyl carbonate purification tower, EMC reaction tower and EMC lightness removal tower at the corresponding time based on the purification time data of the dimethyl carbonate purification tower, the reaction time data of the EMC reaction tower and the lightness removal time data of the EMC lightness removal tower.

[0084] In summary, the safety control method and system in the preparation process of ethyl methyl carbonate provided by the present invention, by arranging a leakage detection device at a designated position of each production equipment, leak detection is performed in the entire preparation process of ethyl methyl carbonate, the leakage detection device emits ultraviolet light to the designated position, when there is dimethyl carbonate or ethyl methyl carbonate leakage, the volatilized dimethyl carbonate or ethyl methyl carbonate is excited by ultraviolet light in the ionization chamber of the leakage detection device, and the excited dimethyl carbonate or ethyl methyl carbonate molecules are ionized into particles to be positively charged and negatively charged, and the charged particles collide with the plate to form a weak current that can be detected, and the weak current is amplified by the amplifier circuit, and the magnitude of the current detected and the degree of leakage are displayed, so that strict leakage monitoring is achieved, and it can be processed in time after the leakage occurs, so as to ensure the leakage safety of the entire production and preparation process. The amplifier circuit includes a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a first capacitor and a differential amplifier. The amplification of the weak current is achieved, so that the micro-leakage can be discovered, and it is avoided that the leakage amount becomes large before it is discovered and causes a large safety hazard.

[0085] By deploying a temperature and pressure prediction model, the data acquisition module obtains relevant historical data and annotates it. The annotated historical data set is input into the temperature and pressure prediction model to train the model, and the temperature and pressure are predicted based on the purification time data of the dimethyl carbonate purification tower, the reaction time data of the EMC reaction tower, and the light removal time data of the EMC light removal tower, so that the temperature and pressure can be adjusted in advance in the subsequent adjustment. Since the adjustment of temperature and pressure is delayed, it is not possible to instantly reach the preset temperature and pressure when adjusting the temperature and pressure. Therefore, by predicting the temperature and pressure through the temperature and pressure prediction model, the temperature and pressure can be adjusted in advance, so that the preset temperature and pressure can be reached at the specified time. The temperature and pressure prediction model sets an input layer, a hidden layer, and an output layer. The input layer is a three-channel, which is used to input temperature data, pressure data, and corresponding time data, respectively, so that the subsequent hidden layer can extract the characteristic relationship between temperature data, pressure data, and corresponding time data. The hidden layer is provided with multiple layers, which are used to capture the relationship between the input temperature data and air pressure data and the corresponding time data. The output layer is used to output the predicted temperature data and air pressure data, and a detailed output calculation formula of the hidden layer is set, so that accurate feature capture can be performed through the hidden layer, and then accurate temperature and air pressure prediction results can be output.

Claims

1. A safety control method in the preparation process of ethyl methyl carbonate, characterized in that: The following steps are involved: S1: inputting industrial-grade dimethyl carbonate into a dimethyl carbonate purification tower, detecting the air pressure in the dimethyl carbonate purification tower by an air pressure detection unit, and when the air pressure detection value is not within a preset air pressure range, adjusting the air pressure in the dimethyl carbonate purification tower by an air pressure regulating unit until the air pressure detection value is within the preset air pressure range; S2: After being purified by the dimethyl carbonate purification tower, the purity of the output dimethyl carbonate is detected by the purity detection unit to determine whether the purity of the output dimethyl carbonate is within a preset purity range. If so, step S3 is executed; if not, the output dimethyl carbonate is returned to the dimethyl carbonate purification tower for re-purification; S3: input the output dimethyl carbonate, catalyst sodium methoxide / methanol solution and anhydrous ethanol into the raw material mixing unit in a specified ratio for mixing, and perform uniformity detection on the mixed raw materials through the uniformity detection unit, and determine whether the uniformity detection result of the mixed raw materials is within the preset uniformity range. If so, execute step S4; if not, continue to mix the raw materials until the uniformity detection result is within the preset uniformity range; S4: sending uniform raw materials into the EMC reaction tower, detecting the air pressure in the EMC reaction tower, and adjusting the air pressure through the air pressure regulating unit when the air pressure in the EMC reaction tower is not within the preset air pressure range, and detecting the temperature in the EMC reaction tower through the temperature detection device, and adjusting the temperature through the temperature regulating unit when the temperature is not within the preset temperature range; S5: The bottom liquid in the EAC reaction tower is transported to a waste catalyst concentration tank for treatment to obtain liquid phase material and gas phase material, the liquid phase material is dried, and the gas phase material is transported to an EMC light removal tower for treatment; S6: Detect the temperature and air pressure in the EAC light removal tower. When the air pressure in the EMC reaction tower is not within the preset air pressure range, the air pressure is adjusted by the air pressure regulating unit. When the temperature is not within the preset temperature range, the temperature is adjusted by the temperature regulating unit. S7: The bottom liquid in the EAC light removal tower is sent to the EMC product tower, and after being cooled by the cooler, the temperature in the cooler is detected. When the temperature of the cooler is not within the preset range, the temperature is adjusted by the temperature adjustment unit, and the cooled object is transported to the EMC finished product tank to obtain the EMC finished product.

2. The safety control method in a process for preparing ethyl methyl carbonate according to claim 1, characterized in that: At the same time as step S1, the temperature in the dimethyl carbonate purification tower is detected by a temperature detection unit, and it is determined whether the temperature detection value is within a preset temperature range. If the temperature detection value is not within the preset temperature range, the temperature in the dimethyl carbonate purification tower is adjusted by a temperature adjustment unit.

3. The safety control method in the preparation process of ethyl methyl carbonate according to claim 1, characterized in that: It also includes the leak detection process, as follows: A leakage detection device is arranged at a designated position of each production equipment, and leakage detection is performed during the entire preparation process of ethyl methyl carbonate. Ultraviolet light is emitted to the designated position by the leakage detection device. When dimethyl carbonate or ethyl methyl carbonate leaks, the volatilized dimethyl carbonate or ethyl methyl carbonate is excited by ultraviolet light in the ionization chamber of the leakage detection device. The excited dimethyl carbonate or ethyl methyl carbonate molecules are ionized into positively charged and negatively charged particles. The charged particles collide with the electrode plate to form a detectable weak current. The weak current is amplified by the amplification circuit. The corresponding leakage degree and leakage position are displayed on the display module according to the detected current size, and an early warning is performed through the early warning module.

4. The safety control method in the preparation process of ethyl methyl carbonate according to claim 3, characterized in that: The amplifying circuit comprises a first resistor (R1), a second resistor (R2), a third resistor (R3), a fourth resistor (R4), a fifth resistor (R5), a sixth resistor (R6), a first capacitor (C1) and a differential amplifier (DA); One end of the first resistor (R1) is connected to the current output positive electrode, and the other end is connected to the current output negative electrode; one end of the second resistor (R2) is connected to the first resistor (R1), and the other end is respectively connected to the inverting input end of the differential amplifier (DA), the first capacitor (C1) and the fourth resistor (R4); the other end of the fourth resistor (R4) and the other end of the first capacitor (C1) are both grounded through the sixth resistor (R6) and connected to the output end of the amplified current; One end of the third resistor (R3) is connected to the first resistor (R1), and the other end is respectively connected to the in-phase input terminal of the differential amplifier (DA) and the fifth resistor (R5). The positive pole of the power supply of the differential amplifier (DA) is connected to a 5V power supply, and the negative pole of the power supply is grounded.

5. The safety control method in the preparation process of ethyl methyl carbonate according to claim 2, characterized in that: A temperature and pressure prediction model is also deployed in each temperature regulating unit and each pressure regulating unit of the dimethyl carbonate purification tower, EMC reaction tower, and EMC light-removal tower. The historical purification time data and the corresponding temperature and pressure data in the purification tower, the historical EMC reaction time data and the corresponding temperature and pressure data in the EMC reaction tower, the historical light-removal time data in the EMC light-removal tower and the corresponding temperature and pressure data in the EMC light-removal tower are obtained by the data acquisition module to construct a historical data set, and the historical data set is annotated. The annotated historical data set is input into the temperature and pressure prediction model to train the model.

6. The safety control method in the preparation process of ethyl methyl carbonate according to claim 5, characterized in that: In the dimethyl carbonate purification stage, the purification time data of the dimethyl carbonate purification tower is obtained through the data acquisition module, and the purification time data is input into the temperature and pressure prediction model. The temperature and pressure prediction model predicts the temperature and pressure corresponding to the purification time data, draws a relationship diagram between the temperature and pressure and the purification time change, and generates a relationship diagram between the temperature and pressure adjustment amount and the purification time; In the EMC reaction stage, the reaction time data of the EMC reaction tower is obtained through the data acquisition module, and the reaction time data is input into the temperature and pressure prediction model. The temperature and pressure prediction model predicts the temperature and pressure corresponding to the reaction time data, draws a relationship diagram between the temperature and pressure and the reaction time change, and generates a relationship diagram between the temperature and pressure adjustment amount and the reaction time; In the EMC delightening stage, the delightening time data of the EMC delightening tower is obtained through the data acquisition module, and the delightening time data is input into the temperature and pressure prediction model. The temperature and pressure prediction model predicts the temperature and pressure corresponding to the delightening time data, draws a relationship diagram between the temperature and pressure and the delightening time change, and generates a relationship diagram between the temperature and pressure adjustment amount and the delightening time; The temperature regulating unit and the air pressure regulating unit directly obtain the temperature and air pressure regulating amounts that change with time in each stage through the temperature and air pressure regulating amount and purification time relationship diagram, the temperature and air pressure regulating amount and reaction time relationship diagram, and the temperature and air pressure regulating amount and light removal time relationship diagram, and realize early adjustment of the temperature and air pressure based on the temperature and air pressure regulating amounts, so that the specified temperature and air pressure can be reached at the corresponding time point.

7. The safety control method in the preparation process of ethyl methyl carbonate according to claim 6, characterized in that: In the process of the temperature adjustment unit and the air pressure adjustment unit adjusting the temperature and air pressure based on the temperature and air pressure adjustment amount, the temperature detection unit and the air pressure detection unit respectively detect the temperature and air pressure of the corresponding equipment in real time, and judge whether the prediction result of the temperature and air pressure prediction model is accurate based on the real-time detection result. If inaccurate, the inaccurate temperature or air pressure and the corresponding time point are fed back to the temperature adjustment unit and the air pressure adjustment unit to adjust the temperature and air pressure adjustment amount.

8. The safety control method in the preparation process of ethyl methyl carbonate according to claim 6, characterized in that: The temperature and air pressure prediction model is a neural network model, including an input layer, a hidden layer and an output layer. The input layer has three channels, which are respectively used to input temperature data, air pressure data and corresponding time data. The corresponding time data are purification time data, EMC reaction time data and EMC lightening time data. The hidden layer has multiple layers, which are used to capture the relationship between the input temperature data and air pressure data and the corresponding time data. The output layer is used to output the predicted temperature data and air pressure data.

9. The safety control method in the preparation process of ethyl methyl carbonate according to claim 8, characterized in that: The output calculation formula of the hidden layer is as follows: Z k =f(w k1 *X1+w k2 *X2+···+w ki *X i +w kn *X n ): Among them, Z k is the output of the hidden layer, f is a nonlinear function, w k1 is the weight between the first node of the input layer and the kth node of the hidden layer, w k2 is the weight between the second node of the input layer and the kth node of the hidden layer, w ki is the weight between the i-th node in the input layer and the k-th node in the hidden layer, w kn is the weight between the nth node in the input layer and the kth node in the hidden layer, X1 is the input of the first node in the input layer, X2 is the input of the second node in the input layer, and X i is the input of the i-th node in the input layer, X n is the input of the nth node in the input layer.

10. A safety control system in the process of preparing ethyl methyl carbonate, used to implement the safety control method in the process of preparing ethyl methyl carbonate according to any one of claims 1 to 9, characterized in that: It includes a data acquisition module, a purity detection unit, a uniformity detection unit, an air pressure regulating unit, a temperature regulating unit, and a temperature and air pressure prediction model. The data acquisition module is provided with a plurality of units, which are respectively arranged in a dimethyl carbonate purification tower, an EMC reaction tower, and an EAC light removal tower. The data acquisition module includes an air pressure detection unit and a temperature detection unit. The purity detection unit is arranged at the output end of the dimethyl carbonate purification tower, the uniformity detection unit is arranged inside the raw material mixing unit, the air pressure regulating unit and the temperature regulating unit are connected to the dimethyl carbonate purification tower, the EMC reaction tower, and the EAC light removal tower, and the temperature and air pressure prediction model is connected to the data acquisition module, the air pressure regulating unit, and the temperature regulating unit; The data acquisition module is used to acquire various historical data and real-time data in the dimethyl carbonate purification tower, the EMC reaction tower and the EAC lightness removal tower; The uniformity detection unit is used to detect the uniformity of the raw materials in the raw material mixing unit; The gas pressure regulating unit is used to regulate the gas pressure in the dimethyl carbonate purification tower, the EMC reaction tower and the EAC lightness removal tower; The temperature regulating unit is used to regulate the temperature in the dimethyl carbonate purification tower, the EMC reaction tower and the EAC light removal tower; The temperature and pressure prediction model is used for the purification time data of the dimethyl carbonate purification tower, the reaction time data of the EMC reaction tower and the light removal time data of the EMC light removal tower to predict the temperature and pressure of the dimethyl carbonate purification tower, the EMC reaction tower and the EMC light removal tower at the corresponding time.

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