Glycolide purification system

Abstract

The utility model belongs to the technical field of glycolide, and relates to a glycolide purification system which comprises a first stirring kettle, a second stirring kettle, a feeding assembly, a discharging assembly, a solvent adding assembly and a central control platform, the feeding assembly, the discharging assembly and the solvent adding assembly are all connected with the first stirring kettle and the second stirring kettle; the central control platform is used for controlling the working states of the feeding assembly, the discharging assembly and the solvent adding assembly; according to the utility model, when the feeding amount of the crude glycolide reaches a preset value, the central control platform automatically adjusts the states of related components, the conveying process of the crude glycolide is switched from the current stirring kettle to another stirring kettle, and a solvent is automatically added into the corresponding stirring kettle according to a preset mass ratio; the automatic control of the proportioning process of the crude glycolide and the solvent is realized, the accuracy of the mass proportioning of the crude glycolide and the solvent is ensured, and the problem of unqualified product quality caused by proportioning deviation is prevented.

Description

TECHNICAL FIELD

[0001] The utility model relates to a glycolide technical field, specifically to a glycolide purification system. BACKGROUND

[0002] In the production process of dimethyl oxalate polyglycolic acid, the purification of glycolide is a key link. The glycolide purification unit usually relies on a variety of solvents and activated carbon adsorption means to remove impurities in the crude glycolide; specifically, through a series of operations such as beating washing, crystallization, filtration and drying, etc., the purification of glycolide is realized. The operation precision of the glycolide purification unit, especially the accurate ratio of crude glycolide and solvent, is crucial to the quality and stability of the final product.

[0003] There is a certain research on the purification method of crude glycolide in the prior art. Referring to patent literature with application number 202410736782.9, a method for purifying crude glycolide is disclosed, which comprises the following steps: (1) adding liquid crude glycolide into a crystal generator containing stirring state and washing solvent, forming a crystal solution, and cooling the crystal solution to 0℃~40℃; (2) introducing the crystal solution into a three-in-one stirring kettle, then filtering, removing the rich solvent, and the rich solvent goes to the solvent recovery unit; (3) adding poor solvent to the three-in-one stirring kettle to wash and filter the crystals; (4) repeating step (3) one or more times; (5) drying the crystals in the three-in-one stirring kettle to obtain purified glycolide. As can be seen, by mixing crude glycolide with washing solvent, impurities in crude glycolide are dissolved in the solvent to form a mixed solution; then, the mixed solution is cooled to promote the precipitation of impurities and the formation of crystals, the crystal solution is introduced into a three-in-one stirring kettle for filtration to remove the solvent rich in impurities, the poor solvent is added to the stirring kettle for multiple washing and filtration of the crystals to further remove impurities, and finally the washed crystals are dried in the stirring kettle to complete the purification of glycolide.

[0004] However, during the ratio and feeding process of crude glycolide and solvent, the operator needs to remotely observe the liquid level change in the stirring kettle on the screen and manually control the corresponding feeding valve of crude glycolide and solvent. Due to the error of liquid level observation and the delay of manual operation, the mass ratio between crude glycolide and solvent often deviates; and the accurate ratio of crude glycolide and solvent is the key to ensure product quality, and inaccurate ratio will directly affect the quality and stability of the product, leading to unqualified product quality, and thus affecting the efficiency and benefit of the entire production line. UTILITY MODEL CONTENTS

[0005] In order to solve the technical problem that the operator remotely observes the liquid level change in the stirring kettle on the screen and manually controls the corresponding feeding valve of the crude glycolide and the solvent, resulting in the deviation of the mass ratio between the crude glycolide and the solvent in the background art, the utility model provides a glycolide purification system.

[0006] The utility model discloses a glycolide purification system, through setting up the connection of central control platform and feeding assembly, discharge assembly and solvent adding assembly, has realized the automation control of crude glycolide and solvent ratio process, specific, when the feeding amount of crude glycolide in the first stirring kettle or second stirring kettle reaches the preset value, the central control platform automatically adjusts the state of relevant components, switches the conveying process of crude glycolide from the current stirring kettle to another stirring kettle, and adds solvent to the corresponding stirring kettle according to the preset mass ratio. This automatic control process effectively avoids the error and delay caused by remote observation of the liquid level change and manual operation, ensures the accuracy of the mass ratio between the crude glycolide and the solvent, improves the quality and stability of the product, prevents the product quality from being unqualified due to the deviation of the ratio, and further improves the efficiency and benefit of the whole production line.

[0007] To solve the above technical problems, the utility model provides the following technical scheme:

[0008] A glycolide purification system, comprising a first stirring kettle, a second stirring kettle, a feeding assembly, a discharge assembly, a solvent adding assembly and a central control platform, wherein the first stirring kettle and the second stirring kettle are reaction containers for crude glycolide and solvent; the feeding assembly is connected to the first stirring kettle and the second stirring kettle and used for conveying crude glycolide; the discharge assembly is connected to the first stirring kettle and the second stirring kettle and used for discharging the mixture of solvent and crude glycolide; the solvent adding assembly is connected to the first stirring kettle and the second stirring kettle and used for conveying solvent; and the central control platform is used for controlling the working state of the feeding assembly, the discharge assembly and the solvent adding assembly.

[0009] In a specific implementation, the feeding assembly comprises a first main pipe, a first feeding valve, a second feeding valve and a first flow meter; the first main pipe is provided with a first branch pipe branching to the first stirring kettle and a second branch pipe branching to the second stirring kettle; the first feeding valve is installed on the first branch pipe, the second feeding valve is installed on the second branch pipe, and the first flow meter is installed on the first main pipe; wherein the first feeding valve, the second feeding valve and the first flow meter are connected to the central control platform.

[0010] In one specific implementation, the feed assembly includes a first main pipe, a first feed valve, a second feed valve, and two first flow meters; the first main pipe is provided with a first branch pipe branching to the first stirred tank and a second branch pipe branching to the second stirred tank; the first feed valve is installed on the first branch pipe, the second feed valve is installed on the second branch pipe, and the two first flow meters are respectively installed on the first branch pipe and the second branch pipe; wherein the first feed valve, the second feed valve, and the two first flow meters are connected with the central control platform.

[0011] In one specific implementation, the solvent addition assembly includes a second main pipe, a first solvent feed valve, a second solvent feed valve, and a second flow meter; the second main pipe is provided with a third branch pipe branching to the first stirred tank and a fourth branch pipe branching to the second stirred tank; the first solvent feed valve is installed on the third branch pipe, the second solvent feed valve is installed on the fourth branch pipe, and the second flow meter is installed on the second main pipe; wherein the first solvent feed valve, the second solvent feed valve, and the second flow meter are connected with the central control platform.

[0012] In one specific implementation, the solvent addition assembly includes a second main pipe, a first solvent feed valve, a second solvent feed valve, and two second flow meters; the second main pipe is provided with a third branch pipe branching to the first stirred tank and a fourth branch pipe branching to the second stirred tank; the first solvent feed valve is installed on the third branch pipe, the second solvent feed valve is installed on the fourth branch pipe, and the two second flow meters are respectively installed on the third branch pipe and the fourth branch pipe; wherein the first solvent feed valve, the second solvent feed valve, and the two second flow meters are connected with the central control platform.

[0013] In one specific implementation, the discharge assembly includes a first discharge pipe, a second discharge pipe, a first discharge valve, and a second discharge valve; the first discharge pipe is in communication with the first stirred tank, and the second discharge pipe is in communication with the second stirred tank; the first discharge valve is installed on the first discharge pipe, the second discharge valve is installed on the second discharge pipe, and the first discharge valve and the second discharge valve are both connected with the central control platform.

[0014] In one specific implementation, the inner walls of the first stirred tank and the second stirred tank are both connected with temperature sensors; the temperature sensors are connected with the central control platform for real-time measurement of the temperature in the first stirred tank and the second stirred tank.

[0015] In one specific implementation, the inner walls of the first stirred tank and the second stirred tank are both connected with time sensors; the time sensors are connected with the central control platform for metering the reaction time of the crude glycolide and the solvent in the first stirred tank and the second stirred tank.

[0016] In one specific embodiment, the glycolide purification system further comprises a drying kettle; the drying kettle is in communication with the first discharge pipeline and the second discharge pipeline, and is used for further processing of the mixed solution discharged by the first discharge pipeline and / or the second discharge pipeline.

[0017] In summary, the utility model has the following beneficial technical effects:

[0018] 1. The glycolide purification system of the utility model, through the connection of the central control platform and the feed assembly, the discharge assembly and the solvent adding assembly, the automation control of the crude glycolide and solvent ratio process is realized;Specifically, when the feed amount of crude glycolide in the first stirring kettle or the second stirring kettle reaches the preset value, the central control platform automatically adjusts the state of the related components, switches the conveying process of crude glycolide from the current stirring kettle to another stirring kettle, and automatically adds solvent to the corresponding stirring kettle according to the preset quality ratio. This automatic control process effectively avoids the errors and delays caused by remote observation of liquid level changes and manual operation, ensures the accuracy of the quality ratio between crude glycolide and solvent, improves the quality and stability of the product, prevents the product quality from being unqualified due to ratio deviation, and further improves the efficiency and benefit of the entire production line.

[0019] 2. The glycolide purification system of the utility model, the temperature sensor and the time sensor are matched with each other, the temperature sensor detects the temperature in the first stirring kettle and the second stirring kettle in real time, and at the same time, when the solvent adding is completed and the corresponding first solvent valve or second solvent valve is closed, the time sensor starts timing;Once the temperature and reaction time reach the preset value, the central control platform automatically controls the corresponding first discharge valve and second discharge valve to open, and the mixed solution is discharged. Through the double-precision control of the temperature sensor and the time sensor, it is ensured that the impurities in the crude glycolide are fully dissolved in the solvent, the purification precision of the crude glycolide is improved, and the quality and stability of the product are improved. At the same time, through the automatic control process, the waste of time is avoided, and the efficiency of the entire production line is further improved. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 It is the overall structure schematic view of the glycolide purification system of the utility model.

[0021] Explanation of reference numerals: 1, first stirring kettle;11, first feed valve;12, first discharge valve;13, first solvent valve;2, second stirring kettle;21, second feed valve;22, second discharge valve;23, second solvent valve;3, first flowmeter;4, second flowmeter. DETAILED DESCRIPTION

[0022] The technical scheme of the utility model will be further explained and described below in combination with the drawings and embodiments, but the utility model is not limited to the following described embodiments.

[0023] In the production process of dimethyl oxalate to polyglycolic acid, the purification of glycolide is a key link. In normal production operation, crude glycolide with a purity of 70-80% is purified by adopting the mode of double sets of devices alternating operation. By injecting solvent into the crude glycolide, the impurities in the crude glycolide are dissolved in the solvent, and the glycolide is insoluble in the solvent, so that the preliminary separation of the impurities and the glycolide is realized. Subsequently, the mixed solution of the solvent and the crude glycolide is transported to a drying kettle, and the glycolide is separated out by heating and / or reduced pressure distillation, so that the glycolide with a purity of 95% is finally obtained, and the purification of the glycolide is realized.

[0024] Referring to Figure 1 A glycolide purification system, comprising: a first stirred tank 1, a second stirred tank 2, a feeding assembly, a discharging assembly, a solvent adding assembly and a central control platform. The first stirred tank 1 and the second stirred tank 2 are both reaction containers of crude glycolide and solvent; the feeding assembly is connected with the first stirred tank 1 and the second stirred tank 2 and is used for conveying crude glycolide; the discharging assembly is connected with the first stirred tank 1 and the second stirred tank 2 and is used for discharging the mixed solution of the solvent and the crude glycolide; the solvent adding assembly is connected with the first stirred tank 1 and the second stirred tank 2 and is used for conveying solvent; the central control platform is used for controlling the working states of the feeding assembly, the discharging assembly and the solvent adding assembly; wherein the mass ratio range of the crude glycolide in the first stirred tank 1 and the second stirred tank 2 to the solvent added through the solvent adding assembly is both 1:(1.2-1.4).

[0025] Specifically, the central control platform in the utility model is a term known to those skilled in the art, which refers to a platform for centralized control and management of various links such as production equipment and production logistics in the production process of a factory.

[0026] Specifically, the impurities contained in the crude glycolide include methanol, water, oligomers, methyl glycolate, dimethyl oxalate and methoxy methyl glycolate, and the solvent in the utility model is dichloromethane.

[0027] Specifically, the mass ratio of the crude glycolide to the solvent can be 1:1.2, 1:1.3 or 1:1.4, and the appropriate mass ratio is set according to the production requirements to achieve the expected purity of glycolide. Preferably, the mass ratio of the crude glycolide to the solvent is 1:1.3, the amount of crude glycolide entering the first stirred tank and the second stirred tank is 1.3T, and the amount of solvent is 1.69T, i.e. M1=M2=1.3T and N1=N2=1.69T.

[0028] Referring to Figure 1The feed assembly comprises a first main pipe, a first feed valve 11, a second feed valve 21 and a first flow meter 3. The first main pipe is provided with a first branch pipe branching to the first stirred tank 1 and a second branch pipe branching to the second stirred tank 2; the first feed valve 11 is installed on the first branch pipe, the second feed valve 21 is installed on the second branch pipe, and the first flow meter 3 is installed on the first main pipe; wherein the first feed valve 11, the second feed valve 21 and the first flow meter 3 are connected with the central control platform.

[0029] With reference to Figure 1 The solvent adding assembly comprises a second main pipe, a first solvent feed valve, a second solvent feed valve and a second flow meter 4. The second main pipe is provided with a third branch pipe branching to the first stirred tank 1 and a fourth branch pipe branching to the second stirred tank 2; the first solvent feed valve is installed on the third branch pipe, the second solvent feed valve is installed on the fourth branch pipe, and the second flow meter 4 is installed on the second main pipe; wherein the first solvent feed valve, the second solvent feed valve and the second flow meter 4 are connected with the central control platform.

[0030] With reference to Figure 1 The discharge assembly comprises a first discharge pipeline, a second discharge pipeline, a first discharge valve 12 and a second discharge valve 22. The first discharge pipeline is communicated with the first stirred tank 1, and the second discharge pipeline is communicated with the second stirred tank 2; the first discharge valve 12 is installed on the first discharge pipeline, the second discharge valve 22 is installed on the second discharge pipeline, and the first discharge valve 12 and the second discharge valve 22 are connected with the central control platform.

[0031] With reference to Figure 1 The inner walls of the first stirred tank 1 and the second stirred tank 2 are connected with temperature sensors; the temperature sensors are connected with the central control platform and are used for measuring the temperatures in the first stirred tank 1 and the second stirred tank 2 in real time.

[0032] Specifically, according to the temperature of the slurry in the stirred tank, the temperature values in the first stirred tank 1 and the second stirred tank 2 are set as 30 DEG C, that is, the temperature requirement of the mixed liquid is met; that is, T1=T2=30 DEG C.

[0033] In the utility model, the temperature sensors detect the temperatures in the first stirred tank 1 and the second stirred tank 2 in real time, and are used in cooperation with the time sensors; once the temperature and the reaction time both reach the preset values, the central control platform automatically controls the corresponding first discharge valve 12 and the second discharge valve 22 to open to discharge the mixed liquid. The automatic process of the temperature and time double control significantly improves the production efficiency and simultaneously ensures the stability and consistency of the product quality.

[0034] With reference to Figure 1The time sensor is connected with the central control platform, and is used for measuring the reaction time of the crude glycolide and the solvent in the first stirred tank 1 and the second stirred tank 2. When the first solvent valve or the second solvent valve is closed, the central control platform automatically triggers the beating and washing operation of the crude glycolide and the solvent, and the time sensor starts timing at the moment when the crude glycolide and the solvent in the first stirred tank 1 or the second stirred tank 2 start beating and washing. The beating and washing operation of the crude glycolide and the solvent can promote the impurities in the crude glycolide to dissolve in the solvent, and further improve the purity of the glycolide. The beating and washing operation is a known operation in the art, and will not be described in detail here.

[0035] Specifically, according to the beating and washing time in the stirred tank, after the solvent is added and the corresponding first solvent valve 13 or second solvent valve 23 is closed, the time sensor is timed for 1 hour, that is, the reaction time requirement of the mixed liquid is met; that is, H1 = H2 = 1 hour.

[0036] In the utility model, when the solvent is added and the corresponding first solvent valve 13 or second solvent valve 23 is closed, the time sensor starts timing, and is used in cooperation with the temperature sensor. Once the temperature and the reaction time reach the preset value, the central control platform automatically controls the corresponding first discharge valve 12 and second discharge valve 22 to open, and the mixed liquid is discharged. The automatic process of the temperature and time double control significantly improves the production efficiency, and at the same time ensures the stability and consistency of the product quality.

[0037] Referring to Figure 1 The glycolide purification system further comprises a drying tank. The drying tank is in communication with the first discharge pipeline and the second discharge pipeline, and is used for further processing the mixed liquid discharged from the first discharge pipeline and / or the second discharge pipeline.

[0038] Specifically, after the mixed liquid discharged from the first discharge pipeline and / or the second discharge pipeline enters the drying tank, heating and reduced pressure distillation operations are performed. These operations are conventional processes in the art. The solvent (such as dichloromethane) is evaporated by heating, and the glycolide is further purified by using the reduced pressure distillation technology to remove residual trace impurities. After the drying tank treatment, glycolide with a purity of 95% is obtained.

[0039] Example 1:

[0040] Referring to Figure 1The glycolide purification system of the embodiment, the feed assembly includes a first main pipe, a first feed valve 11, a second feed valve 21 and two first flow meters 3. The first main pipe is provided with a first branch pipe branching to the first stirred tank 1 and a second branch pipe branching to the second stirred tank 2; the first feed valve 11 is installed on the first branch pipe, the second feed valve 21 is installed on the second branch pipe, and the two first flow meters 3 are respectively installed on the first branch pipe and the second branch pipe; wherein the first feed valve 11, the second feed valve 21 and the two first flow meters 3 are connected with the central control platform.

[0041] Specifically, the two first flow meters 3 are respectively installed on the first branch pipe and the second branch pipe, when starting feeding, the central control platform monitors the real-time flow of the first flow meter 3 on the first branch pipe and the second branch pipe respectively; when the real-time flow of the first flow meter 3 on the first branch pipe reaches the set crude glycolide amount M1, the central control platform controls the first feed valve 11 to close, and clears the real-time flow of the first flow meter 3 on the first branch pipe; when the real-time flow of the first flow meter 3 on the second branch pipe reaches the set crude glycolide amount M2, the central control platform controls the second feed valve 21 to close, and clears the real-time flow of the first flow meter 3 on the second branch pipe.

[0042] In the embodiment, one first flow meter 3 is arranged on each of the first branch pipe and the second branch pipe, which facilitates the central control platform to monitor the flow of the solvent in the first branch pipe and the second branch pipe in real time, when the real-time flow of the first flow meter 3 on any branch pipe reaches the preset crude glycolide amount (M1 or M2), the central control platform can immediately control the corresponding feed valve (the first feed valve 11 or the second feed valve 21) to close, and clear the real-time flow of the first flow meter 3 on the corresponding branch pipe. This real-time monitoring and accurate control method can accurately control the amount of crude glycolide added in each stirred tank, and can avoid unnecessary downtime, thereby further improving the operation efficiency of the entire glycolide purification system.

[0043] Embodiment 2:

[0044] Referring to Figure 1 The glycolide purification system of the embodiment, the solvent adding assembly includes a second main pipe, a first solvent feed valve, a second solvent feed valve and two second flow meters 4. The second main pipe is provided with a third branch pipe branching to the first stirred tank 1 and a fourth branch pipe branching to the second stirred tank 2; the first solvent feed valve is installed on the third branch pipe, the second solvent feed valve is installed on the fourth branch pipe, and the two second flow meters 4 are respectively installed on the third branch pipe and the fourth branch pipe; wherein the first solvent feed valve, the second solvent feed valve and the two second flow meters 4 are connected with the central control platform.

[0045] Specifically, two second flow meters 4 are installed on the third and fourth branch pipes respectively. When solvent is added, the central control platform monitors the real-time flow of the second flow meters 4 on the third and fourth branch pipes respectively. When the real-time flow of the second flow meter 4 on the third branch pipe reaches the set solvent volume N1, the central control platform controls the first solvent valve 13 to close and resets the real-time flow of the second flow meter 4 on the third branch pipe to zero. When the real-time flow of the second flow meter 4 on the fourth branch pipe reaches the set solvent volume N2, the central control platform controls the second solvent valve 23 to close and resets the real-time flow of the second flow meter 4 on the fourth branch pipe to zero.

[0046] In this embodiment, a second flow meter 4 is installed on each of the third and fourth branch pipes to facilitate real-time monitoring of the solvent flow rate in the third and fourth branch pipes by the central control platform. When the real-time flow rate of the second flow meter 4 on either branch pipe reaches the preset solvent amount (N1 or N2), the central control platform can immediately control the corresponding solvent valve (first solvent valve 13 or second solvent valve 23) to close and reset the real-time flow rate of the second flow meter 4 on the corresponding branch pipe to zero. This real-time monitoring and precise control method can accurately control the amount of solvent added to each stirred tank, while avoiding unnecessary downtime, thereby further improving the operating efficiency of the entire glycolide purification system.

[0047] The purification steps of the glycolide purification system of this utility model are as follows:

[0048] S1. Initial Preparations:

[0049] According to the mass ratio of crude glycolide to solvent, the amount of crude glycolide M1 and solvent N1 entering the first stirred tank 1, the temperature T1 inside the first stirred tank 1, and the reaction time H1 between crude glycolide and solvent are set, and the central control platform monitors the real-time temperature t1 inside the first stirred tank 1.

[0050] According to the mass ratio of crude glycolide to solvent, the amount of crude glycolide M2 ​​and solvent N2 entering the second stirred tank 2, the temperature T2 inside the second stirred tank 2, and the reaction time H2 between crude glycolide and solvent are set, and the central control platform monitors the real-time temperature t2 inside the second stirred tank 2.

[0051] S2, crude lactide alternating feed:

[0052] S2.1, Start feeding the first mixing vessel 1;

[0053] S2.1.1 Check whether the first discharge valve 12, the second feed valve 21, and the first solvent valve 13 are all in the closed state;

[0054] If so, proceed to step S2.1.2;

[0055] If not, then wait;

[0056] S2.1.2. The central control platform monitors the real-time flow rate m1 of the first flowmeter 3.

[0057] S2.1.3. The central control platform controls the first feed valve 11 to open, and the crude glycolide flows through the first flowmeter 3 and the first feed valve 11 in sequence and enters the first stirring kettle 1.

[0058] S2.1.4. The central control platform compares the real-time flow rate m1 of the first flowmeter 3 with the set amount M1 of the crude glycolide.

[0059] When m1 < M1, step S2.1.3 is executed.

[0060] When m1 = M1, step S2.1.5 is executed.

[0061] S2.1.5. The central control platform controls the first feed valve 11 to close, clears the real-time flow rate m1 of the first flowmeter 3, and simultaneously executes step S2.2 and step S3.1.

[0062] S2.2. Start the feeding of the second stirring kettle 2.

[0063] S2.2.1. Check whether the second discharge valve 22, the first feed valve 11, and the second solvent valve 23 are all in the closed state.

[0064] If so, enter step S2.2.2.

[0065] If not, wait.

[0066] S2.2.2. The central control platform monitors the real-time flow rate m2 of the first flowmeter 3.

[0067] S2.2.3. The central control platform controls the second feed valve 21 to open, and the crude glycolide flows through the first flowmeter 3 and the second feed valve 21 in sequence and enters the second stirring kettle 2.

[0068] S2.2.4. The central control platform compares the real-time flow rate m2 of the first flowmeter 3 with the set amount M2 of the crude glycolide.

[0069] When m2 < M2, step S2.2.3 is executed.

[0070] When m2 = M2, step S2.2.5 is executed.

[0071] S2.2.5. The central control platform controls the second feed valve 21 to close, clears the real-time flow rate m2 of the first flowmeter 3, and simultaneously executes step S2.1 and step S3.2.

[0072] S3. Solvent addition:

[0073] S3.1. Add solvent to the first stirring kettle 1:

[0074] S3.1.1. The central control platform monitors the real-time flow rate n1 of the second flowmeter 4;

[0075] S3.1.2. The central control platform controls the first solvent valve 13 to open, and the solvent flows through the second flowmeter 4 and the first solvent valve 13 in sequence and enters the first stirring kettle 1 to form a mixed solution;

[0076] S3.1.3. The central control platform compares the real-time flow rate n1 of the second flowmeter 4 with the set solvent amount N1.

[0077] When n1 < N1, step S3.1.2 is executed.

[0078] When n1 = N1, step S3.1.4 is executed;

[0079] S3.1.4. The central control platform controls the first solvent valve 13 to close, clears the real-time flow rate n1 of the second flowmeter 4, controls the time sensor in the second stirring kettle 2 to start timing h1, and synchronously executes step S3.2 and step S4.1;

[0080] S3.2. Adding solvent to the second stirring kettle 2:

[0081] S3.2.1. The central control platform monitors the real-time flow rate n2 of the second flowmeter 4;

[0082] S3.2.2. The central control platform controls the second solvent valve 23 to open, and the solvent flows through the second flowmeter 4 and the second solvent valve 23 in sequence and enters the second stirring kettle 2 to form a mixed solution;

[0083] S3.2.3. The central control platform compares the real-time flow rate n2 of the second flowmeter 4 with the set solvent amount N2.

[0084] When n2 < N2, step S3.2.2 is executed.

[0085] When n2 = N2, step S3.2.4 is executed;

[0086] S3.2.4. The central control platform controls the second solvent valve 23 to close, clears the real-time flow rate n2 of the second flowmeter 4, controls the time sensor in the second stirring kettle 2 to start timing h2, and executes step S4.2;

[0087] S4. Reaction timing and temperature monitoring:

[0088] S4.1. Monitoring the reaction time and temperature of the first stirring kettle 1:

[0089] The central control platform compares the measured real-time temperature t1 with the set temperature value T1, and compares the reaction time h1 of crude glycolide and the solvent with the set reaction time H1.

[0090] When t1 < T1 or h1 < H1, step S4.1 is continued.

[0091] When t1 ≥ T1 and h1 ≥ H1, step S5.1 is executed;

[0092] S4.2. Monitor the reaction time and temperature of the second stirring kettle 2:

[0093] The central control platform compares the measured real-time temperature t2 with the set temperature value T2, and compares the reaction time h2 of crude glycolide and the solvent with the set reaction time H2.

[0094] When t2 < T2 or h2 < H2, step S4.2 is continued.

[0095] When t2 ≥ T2 and h2 ≥ H2, step S5.2 is executed;

[0096] S5. Drainage:

[0097] S5.1. Empty the first stirring kettle 1:

[0098] S5.1.1. The central control platform clears h1 measured by the time sensor in the first stirring kettle 1, controls the first discharge valve 12 to open, and the mixed liquid in the first stirring kettle 1 flows through the first discharge valve 12 and is discharged into the drying kettle;

[0099] S5.1.2. The central control platform controls the first discharge valve 12 to close;

[0100] S5.2. Empty the second stirring kettle 2: [[ID=,34]]

[0101] S5.2.1. The central control platform clears h2 measured by the time sensor in the second stirring kettle 2, controls the second discharge valve 22 to open, and the mixed liquid in the second stirring kettle 2 flows through the second discharge valve 22 and is discharged into the drying kettle;

[0102] S5.2.2. The central control platform controls the second discharge valve 22 to close;

[0103] S6. Separation of glycolide and solvent:

[0104] Heat the mixed liquid in the drying kettle, the solvent dissolved with impurities evaporates, and glycolide is separated from the mixed liquid to obtain glycolide with a purity of 95%, realizing the purification of glycolide.

[0105] The preferred embodiments of this utility model are not intended to limit the scope of protection of this utility model. Therefore, all equivalent changes made to the structure, shape, and principle of this utility model should be included within the scope of protection of this utility model.

Claims

1. A glycolide purification system, characterized in that: include: First mixing vessel (1), second mixing vessel (2), feeding assembly, discharging assembly, solvent adding assembly and central control platform; Both the first stirred tank (1) and the second stirred tank (2) are reaction vessels for crude glycolide and solvent; The feeding assembly is connected to both the first stirring vessel (1) and the second stirring vessel (2) and is used to transport crude glycolide; The discharge assembly is connected to both the first stirring vessel (1) and the second stirring vessel (2) and is used to discharge the mixture of solvent and crude glycolide. The solvent addition assembly is connected to both the first stirred tank (1) and the second stirred tank (2) and is used to transport solvent; The central control platform is used to control the working status of the feeding component, the discharging component, and the solvent addition component.

2. The glycolide purification system according to claim 1, characterized in that: The feeding assembly includes a first main pipe, a first feed valve (11), a second feed valve (21), and a first flow meter (3); The first main pipe is provided with a first branch pipe that branches to the first stirred tank (1) and a second branch pipe that branches to the second stirred tank (2); The first feed valve (11) is installed on the first branch pipe, the second feed valve (21) is installed on the second branch pipe, and the first flow meter (3) is installed on the first main pipe; The first feed valve (11), the second feed valve (21), and the first flow meter (3) are all connected to the central control platform.

3. The glycolide purification system according to claim 1, characterized in that: The feeding assembly includes a first main pipe, a first feed valve (11), a second feed valve (21), and two first flow meters (3); The first main pipe is provided with a first branch pipe that branches to the first stirred tank (1) and a second branch pipe that branches to the second stirred tank (2); The first feed valve (11) is installed on the first branch pipe, the second feed valve (21) is installed on the second branch pipe, and the two first flow meters (3) are respectively installed on the first branch pipe and the second branch pipe; The first feed valve (11), the second feed valve (21), and the two first flow meters (3) are all connected to the central control platform.

4. The glycolide purification system according to claim 2, characterized in that: The solvent addition assembly includes a second main pipe, a first solvent inlet valve, a second solvent inlet valve, and a second flow meter (4); The second main pipe is provided with a third branch pipe that branches to the first stirred tank (1) and a fourth branch pipe that branches to the second stirred tank (2); The first solvent feed valve is installed on the third branch pipe, the second solvent feed valve is installed on the fourth branch pipe, and the second flow meter (4) is installed on the second main pipe; The first solvent feed valve, the second solvent feed valve, and the second flow meter (4) are all connected to the central control platform.

5. The glycolide purification system according to claim 2, characterized in that: The solvent addition assembly includes a second main pipe, a first solvent inlet valve, a second solvent inlet valve, and two second flow meters (4); The second main pipe is provided with a third branch pipe that branches to the first stirred tank (1) and a fourth branch pipe that branches to the second stirred tank (2); The first solvent feed valve is installed on the third branch pipe, the second solvent feed valve is installed on the fourth branch pipe, and the two second flow meters (4) are installed on the third branch pipe and the fourth branch pipe respectively; The first solvent feed valve, the second solvent feed valve, and the two second flow meters (4) are all connected to the central control platform.

6. The glycolide purification system according to claim 4, characterized in that: The discharge assembly includes a first discharge pipe, a second discharge pipe, a first discharge valve (12), and a second discharge valve (22); The first discharge pipe is connected to the first mixing vessel (1), and the second discharge pipe is connected to the second mixing vessel (2); The first discharge valve (12) is installed on the first discharge pipe, and the second discharge valve (22) is installed on the second discharge pipe. Both the first discharge valve (12) and the second discharge valve (22) are connected to the central control platform.

7. The glycolide purification system according to claim 6, characterized in that: Temperature sensors are connected to the inner walls of both the first stirring vessel (1) and the second stirring vessel (2); The temperature sensor is connected to the central control platform and is used to measure the temperature inside the first stirring vessel (1) and the second stirring vessel (2) in real time.

8. The glycolide purification system according to claim 7, characterized in that: Time sensors are connected to the inner walls of both the first stirring vessel (1) and the second stirring vessel (2); The time sensor is connected to the central control platform and is used to measure the reaction time of crude glycolide and solvent in the first stirred tank (1) and the second stirred tank (2).

9. The glycolide purification system according to claim 6, characterized in that: The glycolide purification system also includes a drying kettle; The drying vessel is connected to both the first discharge pipe and the second discharge pipe, and is used to further process the mixture delivered by the first discharge pipe and / or the second discharge pipe.

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