A separation and purification device for dimethyl carbonate

Abstract

The utility model discloses a separation and purification device for dimethyl carbonate, comprising a storage tank, wherein a circulation pump is fixedly installed at one end of the top of the storage tank, a liquid extraction tube is fixedly connected to the input end of the circulation pump, a liquid infusion tube is fixedly connected to the output end of the circulation pump, the top of the liquid infusion tube is fixedly connected to a solution buffer tank, the bottom of the solution buffer tank is fixedly connected to a crystallization coil, a flow regulating valve is installed on the top of the crystallization coil, a condensation jacket tube is sleeved on the bottom of the crystallization coil, a reflux tube is fixedly connected to the bottom end of the crystallization coil, and a product outlet tube is fixedly connected to the middle of the reflux tube. The utility model discloses a separation and purification device for dimethyl carbonate, wherein the separation and purification device utilizes the different solidification points of dimethyl carbonate and methanol under low temperature conditions to perform solid-liquid separation on different components at different temperatures, thereby avoiding the ineffective separation caused by the volatilization of methanol under high temperature conditions.

Description

Technical Field

[0001] The utility model relates to the technical field of separation and purification, in particular to a separation and purification device for dimethyl carbonate. Background Art

[0002] Dimethyl carbonate is an organic compound and a colorless, transparent liquid.

[0003] In the production process of dimethyl carbonate, methanol is used as a synthetic raw material and an absorbent for dimethyl oxalate, resulting in a large amount of methanol aqueous solution in the product. Since methanol is highly volatile, the existing dimethyl carbonate separation and purification device and method have the following disadvantages:

[0004] (1) Since methanol has a high volatility and is miscible with dimethyl carbonate to form an azeotrope, conventional distillation and multi-stage distillation methods cannot separate methanol to the expected index. Under high temperature conditions, methanol volatilizes, resulting in ineffective separation.

[0005] (2) The existing separation and purification device has a poor separation and purification effect on dimethyl carbonate, and the purity obtained cannot meet the demand;

[0006] (3) Existing separation and purification devices often operate under high temperature and high pressure, which has poor safety. Utility Model Content

[0007] The purpose of the utility model is to provide a separation and purification device for dimethyl carbonate to solve the existing problems raised in the above background technology.

[0008] To achieve the above-mentioned purpose, the utility model provides the following technical scheme: a device for separating and purifying dimethyl carbonate, comprising a storage tank, a circulating pump is fixedly installed at one end of the top of the storage tank, the input end of the circulating pump is fixedly connected to a liquid extraction tube, the output end of the circulating pump is fixedly connected to a liquid infusion tube, the top of the liquid infusion tube is fixedly connected to a solution buffer tank, the bottom of the solution buffer tank is fixedly connected to a crystallization coil, a flow regulating valve is installed on the top of the crystallization coil, the bottom of the crystallization coil is provided with a condensation jacket pipe, the bottom end of the crystallization coil is fixedly connected to a reflux pipe, and the middle of the reflux pipe is fixedly connected to a product outlet pipe.

[0009] When a separation and purification device for dimethyl carbonate of the technical solution is used, the separation and purification device utilizes the different freezing points of dimethyl carbonate and methanol under low temperature conditions to perform solid-liquid separation of different components at different temperatures, thereby avoiding ineffective separation caused by methanol volatilization under high temperature conditions.

[0010] As a preferred technical solution of the utility model, the bottom end of the liquid extraction pipe is fixedly connected to the bottom of one end of the storage tank, and the bottom end of the return pipe is fixedly connected to the top of the storage tank. The liquid extraction pipe and the return pipe are used for the circulation of the solution.

[0011] As a preferred technical solution of the utility model, the bottom of the condensation jacket is fixedly connected with a condensation inlet, and the top of the condensation jacket is fixedly connected with a condensation outlet. The condensation inlet and the condensation outlet are used for the circulation of the condensation medium.

[0012] As a preferred technical solution of the utility model, a switch valve 1 is installed at the bottom of the reflux pipe, and a switch valve 2 is installed on the surface of the product outlet pipe. Two switch valves are provided to control the opening and closing of the reflux pipe and the product outlet pipe respectively.

[0013] As a preferred technical solution of the utility model, a bracket is fixedly installed on one side of the top of the storage tank, and the solution buffer tank is fixedly installed on the top of the bracket. The bracket is provided to make the installation of the solution buffer tank more stable.

[0014] As a preferred technical solution of the utility model, a corner of the top of the storage tank is fixedly connected with a liquid injection nozzle. The liquid injection nozzle is provided for injecting solution into the storage tank.

[0015] As a preferred technical solution of the utility model, the top of the liquid injection nozzle is threadedly sleeved with a sealing cover, which can prevent the volatilization of the solution.

[0016] As a preferred technical solution of the utility model, a valve is fixedly connected to one side of the bottom of the front side of the storage tank, and one end of the valve is fixedly connected to a drain pipe. After the valve is opened, the solution or cleaning liquid can be discharged from the drain pipe.

[0017] Compared with the prior art, the beneficial effects of the utility model are:

[0018] 1. The separation and purification device utilizes the different freezing points of dimethyl carbonate and methanol under low temperature conditions to separate different components into solid and liquid at different temperatures, thus avoiding the ineffective separation caused by the volatilization of methanol under high temperature conditions;

[0019] 2. The separation and purification device has a better separation and purification effect on dimethyl carbonate, and high-purity electronic grade dimethyl carbonate is obtained after collection, with a purity of ≥5N grade;

[0020] 3. The device does not require high temperature and high pressure operation, and is easy and safe to operate. The material can be circulated in the crystallization coil for low temperature purification, which is suitable for the separation and purification of other unstable substances that are easily decomposed and volatile at high temperature. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1It is a three-dimensional diagram of the utility model;

[0022] Figure 2 It is a cross-sectional view of the utility model;

[0023] Figure 3 It is a structural schematic diagram of the condensation jacket pipe of the utility model;

[0024] Figure 4 It is a partial cross-sectional view of the utility model.

[0025] In the figure: 1. Storage tank; 2. Circulation pump; 3. Extraction tube; 4. Infusion tube; 5. Solution buffer tank; 6. Flow regulating valve; 7. Crystallization coil; 8. Condensation jacket tube; 9. Reflux pipe; 10. Switch valve 1; 11. Product outlet pipe; 12. Switch valve 2; 13. Condensation outlet; 14. Condensation inlet; 15. Bracket; 16. Liquid injection nozzle; 17. Sealing cover; 18. Valve; 19. Drain pipe. DETAILED DESCRIPTION

[0026] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0027] See also Figure 1-4 The utility model provides a separation and purification device for dimethyl carbonate, comprising a storage tank 1, a circulating pump 2 is fixedly installed at one end of the top of the storage tank 1 for extracting solution, an input end of the circulating pump 2 is fixedly connected with a liquid extraction pipe 3, an output end of the circulating pump 2 is fixedly connected with a liquid infusion pipe 4, the top of the liquid infusion pipe 4 is fixedly connected with a solution buffer tank 5, the bottom of the solution buffer tank 5 is fixedly connected with a crystallization coil 7, a flow regulating valve 6 is installed on the top of the crystallization coil 7 for adjusting the liquid flow, a condensation jacket pipe 8 is provided at the bottom of the crystallization coil 7 for condensation and cooling, a reflux pipe 9 is fixedly connected to the bottom end of the crystallization coil 7, and a product outlet pipe 11 is fixedly connected to the middle of the reflux pipe 9 for discharging the purified product.

[0028] When in use, the superior grade dimethyl carbonate is placed in the solution storage tank 1, the temperature of the condensation jacket tube 8 is controlled to be 5°C, the plunger circulation pump 2 is turned on, the reflux pipe 9 is opened, the product outlet pipe 11 is closed, and the flow regulating valve 6 is adjusted to allow the dimethyl carbonate to flow through the crystallizer tube wall in the form of a liquid film. The operation is carried out for about 30 minutes, and the temperature of the circulating coolant is adjusted to -1°C. When the dimethyl carbonate flows through the crystallization coil 7, crystals are gradually precipitated. When the amount of crystals precipitated on the tube wall is large, the temperature is increased to 3°C to sweat the crystal layer and discharge impurities in the crystal layer. After the sweating is completed, the product outlet pipe 11 is opened, the reflux pipe 9 is closed, the temperature is increased to room temperature to melt the crystals, and high-purity electronic grade dimethyl carbonate is obtained after collection.

[0029] The bottom end of the liquid extraction pipe 3 is fixedly connected to the bottom of one end of the storage tank 1, and the bottom end of the reflux pipe 9 is fixedly connected to the top of the storage tank 1 for the circulation of the solution. The bottom of the condensation jacket pipe 8 is fixedly connected with a condensation inlet 14, and the top of the condensation jacket pipe 8 is fixedly connected with a condensation outlet 13 for the circulation of condensed water. A switch valve 10 is installed at the bottom of the reflux pipe 9, and a switch valve 2 12 is installed on the surface of the product outlet pipe 11 for controlling the circulation of the pipeline.

[0030] When in use, after the circulation pump 2 is started, the solution in the storage tank 1 is extracted by the extraction pipe 3, and the solution will eventually flow back into the storage tank 1 from the reflux pipe 9, and the condensed water is input from the lower condensation inlet 14 and output from the upper condensation outlet 13, which has a cooling effect on the solution in the crystallization coil 7. The opening and closing of the switch valve is used to control the opening or closing of the reflux pipe 9 and the product outlet pipe 11.

[0031] A bracket 15 is fixedly installed on one side of the top of the storage tank 1, and the solution buffer tank 5 is fixedly installed on the top of the bracket 15 to play a supporting role. A corner of the top of the storage tank 1 is fixedly connected to a liquid injection nozzle 16 for injecting solution. A sealing cover 17 is threadedly sleeved on the top of the liquid injection nozzle 16. A valve 18 is fixedly connected to one side of the bottom of the front side of the storage tank 1, and one end of the valve 18 is fixedly connected to a drain pipe 19 for draining liquid.

[0032] When in use, the support 15 provided can support the solution buffer tank 5, making the structure more stable. During operation, the superior dimethyl carbonate is injected into the solution storage tank 1 from the injection nozzle 16, and the sealing cover 17 is rotated to prevent the volatilization of the solution. After the work is completed, the valve 18 can be opened to discharge the solution or cleaning liquid from the drain pipe 19.

[0033] In specific use, the utility model is a separation and purification device for dimethyl carbonate. The freezing point of dimethyl carbonate is 0.5°C, and the freezing point of methanol is -97.8°C. The superior dimethyl carbonate is placed in a solution storage tank 1, the temperature of the condensation jacket 8 is controlled to be 5°C, the plunger circulation pump 2 is turned on, the switch valve 10 is turned on, the switch valve 2 12 is closed, and the flow regulating valve 6 is adjusted so that the dimethyl carbonate flows through the crystallizer tube wall in the form of a liquid film. The operation is about 30 minutes, and the temperature of the circulating coolant is adjusted to -1°C (below the freezing point of dimethyl carbonate). When the dimethyl carbonate flows through the crystallization coil 7, crystals are gradually precipitated. When the amount of crystals precipitated on the tube wall is large, the temperature is increased to 3°C to sweat the crystal layer and discharge impurities in the crystal layer. After the sweating is completed, the switch valve 2 12 is opened, the switch valve 10 is closed, the temperature is increased to room temperature to melt the crystals, and high-purity electronic-grade dimethyl carbonate with a purity of ≥5N is obtained after collection. If the purity is 98. 8% of dimethyl carbonate is placed in a storage tank 1, the flow rate is adjusted to 60 mL / min, the temperature of the crystallization coil 7 is -1°C, and a dimethyl carbonate product with a purity of 99.99 can be obtained after running for 30 minutes; if dimethyl carbonate with a purity of 98.8% is placed in a storage tank 1, the flow rate is adjusted to 55 mL / min, the temperature of the crystallization coil 7 is -2°C, and a dimethyl carbonate product with a purity of 99.98 can be obtained after running for 30 minutes; if dimethyl carbonate with a purity of 98.8% is placed in a storage tank 1, the flow rate is adjusted to 70 mL / min, the temperature of the crystallization coil 7 is -1°C, and a dimethyl carbonate product with a purity of 99.99 can be obtained after running for 30 minutes; if dimethyl carbonate with a purity of 98.8% is placed in a storage tank 1, the flow rate is adjusted to 40 mL / min, the temperature of the crystallization coil 7 is -1°C, and a dimethyl carbonate product with a purity of 99.96 can be obtained after running for 30 minutes.

[0034] Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art may still modify the technical solutions described in the aforementioned embodiments, or make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

Claims

1. A separation and purification device for dimethyl carbonate, comprising a storage tank (1), characterized in that: A circulation pump (2) is fixedly installed at one end of the top of the storage tank (1); the input end of the circulation pump (2) is fixedly connected to a liquid extraction pipe (3); the output end of the circulation pump (2) is fixedly connected to a liquid infusion pipe (4); the top of the liquid infusion pipe (4) is fixedly connected to a solution buffer tank (5); the bottom of the solution buffer tank (5) is fixedly connected to a crystallization coil (7); a flow regulating valve (6) is installed at the top of the crystallization coil (7); a condensation jacket pipe (8) is sleeved at the bottom of the crystallization coil (7); the bottom end of the crystallization coil (7) is fixedly connected to a reflux pipe (9); and the middle of the reflux pipe (9) is fixedly connected to a product outlet pipe (11).

2. A separation and purification device for dimethyl carbonate according to claim 1, characterized in that: The bottom end of the liquid extraction pipe (3) is fixedly connected to the bottom of one end of the storage tank (1), and the bottom end of the return pipe (9) is fixedly connected to the top of the storage tank (1).

3. A separation and purification device for dimethyl carbonate according to claim 1, characterized in that: The bottom of the condensation jacket tube (8) is fixedly connected to a condensation inlet (14), and the top of the condensation jacket tube (8) is fixedly connected to a condensation outlet (13).

4. A separation and purification device for dimethyl carbonate according to claim 1, characterized in that: A first switch valve (10) is installed at the bottom of the return pipe (9), and a second switch valve (12) is installed on the surface of the product outlet pipe (11).

5. A separation and purification device for dimethyl carbonate according to claim 1, characterized in that: A bracket (15) is fixedly mounted on one side of the top of the storage tank (1), and the solution buffer tank (5) is fixedly mounted on the top of the bracket (15).

6. A separation and purification device for dimethyl carbonate according to claim 1, characterized in that: A corner of the top of the storage tank (1) is fixedly connected to a liquid injection nozzle (16).

7. A separation and purification device for dimethyl carbonate according to claim 6, characterized in that: The top of the liquid injection nozzle (16) is threadedly sleeved with a sealing cover (17).

8. A separation and purification device for dimethyl carbonate according to claim 1, characterized in that: One side of the bottom of the front side of the storage tank (1) is fixedly connected to a valve (18), and one end of the valve (18) is fixedly connected to a liquid discharge pipe (19).

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