Vinylidene fluoride production system

Abstract

The utility model relates to a vinylidene fluoride production system. Comprising a liquefying condenser, a light component removal tower connected with the output end of the liquefying condenser, a rectifying tower connected with the output end of the light component removal tower, a finished product recovery tower connected with a tower kettle of the rectifying tower, an emptying tower connected with a tower kettle of the finished product recovery tower and a raw material recovery tower connected with a tower kettle of the emptying tower, the buffer tank is connected with the output end of the material condenser, the top of the buffer tank is connected with the liquefaction condenser, and the bottom of the buffer tank is connected with the finished product recovery tower. After materials are primarily treated through the material condenser and the buffer tank, the purity of VDF entering the rectifying tower is improved, and therefore mass production of VDF with the purity of 99.999% or above is achieved. The water content of materials entering the rectifying tower is reduced, the ice blockage phenomenon of the rectifying tower is eliminated, stable operation of the system is prevented from being affected, and meanwhile the productivity of the rectifying tower in the same unit time can be improved.

Description

Technical Field

[0001] The utility model relates to the field of metal production, and more specifically, to a vinylidene fluoride production system. Background Art

[0002] Vinylidene fluoride, abbreviated as VDF, is mainly used to produce polyvinylidene fluoride and is used as a monomer raw material for fluororesins and fluororubbers. Generally, 1-chloro-1,1-difluoroethane is used as a raw material, and through tube cracking or steam dilution cracking, followed by carbon removal, water washing, freeze dehydration, compression, liquefaction, and then entering rectification to produce finished products and recycle unreacted raw materials. Currently, at home and abroad, the production of VDF mainly separates and purifies VDF through five or six rectification towers.

[0003] The existing technical solution is to input materials into a liquefaction condenser. The VDF purity of this part of the materials is 80%. After liquefaction, the materials enter a de-light tower to remove light components, and then enter a rectification tower for rectification. VDF with a purity of 99.99% is taken out from the top of the rectification tower. The heavy components in the bottom of the rectification tower then enter a VDF recovery tower to recover a small amount of VDF, and then enter a venting tower to vent the intermediate components between the finished VDF and the raw material R142b, and then enter a raw material recovery tower to recover the raw material R142b from the top. The bottom of the raw material recovery tower discharges residual liquid. Among them, the light components refer to air mixtures, the intermediate components refer to vinylidene chloride and R152a with boiling points between VDF and R142b, and the heavy components refer to R142b. Summary of the Utility Model

[0004] In order to overcome the problem that the purity of VDF in the above technical solution is only 99.99%, the utility model provides a vinylidene fluoride production system, which can further improve the purity of VDF and reach a purity of more than 99.999%.

[0005] To solve the above technical problems, the technical solution adopted by the utility model is: a vinylidene fluoride production system, including a liquefaction condenser, a de-light tower connected to the output end of the liquefaction condenser, a rectification tower connected to the output end of the de-light tower, a finished product recovery tower connected to the bottom of the rectification tower, a venting tower connected to the bottom of the finished product recovery tower, and a raw material recovery tower connected to the bottom of the venting tower; it also includes a material condenser and a buffer tank connected to the output end of the material condenser. The top of the buffer tank is connected to the liquefaction condenser, and the bottom of the buffer tank is connected to the finished product recovery tower.

[0006] In the above technical solution, the material with 80% VDF purity is transported to the material condenser. Through the action of the material condenser, the water and heavy components in the material are liquefied, while VDF remains in a gaseous state. The liquefied water and heavy components enter the bottom of the buffer tank, and the gaseous material accumulates at the top of the buffer tank. The gaseous material mainly contains VDF. And due to the action of the material condenser, after the water and heavy components in the material are removed, the gaseous material is in a dry material state and the VDF purity reaches 98%. The gaseous VDF of this part of the material enters the liquefaction condenser, where the gaseous VDF is liquefied and then enters the light component removal tower to remove light components, and then enters the rectification tower for rectification. Since the purity of the VDF entering the rectification tower has reached 98%, the rectification effect of the rectification tower is further improved. Therefore, VDF with a purity of 99.999% is taken out from the top of the rectification tower, and the heavy components in the bottom of the rectification tower enter the VDF recovery tower to recover a small amount of VDF, and then enter the venting tower to vent the intermediate components between the finished VDF and the raw material R142b, and then enter the raw material recovery tower to recover the raw material R142b from the top, and the bottom of the raw material recovery tower discharges the residual liquid. Since the moisture in the material has been separated from the gaseous VDF at the buffer tank, the water content in the material entering the rectification tower is reduced to less than 100 ppm and no visible water can be formed, eliminating the phenomenon of ice blockage in the rectification tower; at the same time, the material input amount of the rectification tower is limited, because if there is more moisture in the material, the amount of VDF that can be produced each time will be less, and when the moisture content decreases, the amount of VDF produced each time will increase, thus improving the production capacity of the rectification tower. And the water and heavy components enter the finished product recovery tower through the bottom of the buffer tank to further recover VDF from this part of the material.

[0007] Preferably, the material condenser and the buffer tank are both provided with a first regulating valve for controlling the refrigerant inflow rate. The temperature of the material condenser and the buffer tank can be adjusted through the regulating valve to better separate the gaseous VDF from the water and heavy components. Keeping the temperature of the buffer tank at a relatively low temperature, such as 0 - 20 degrees Celsius, can gasify the VDF mixed in the water and heavy components at the bottom of the buffer tank again, reducing the processing amount of the finished product recovery tower.

[0008] Preferably, the material condenser and the buffer tank are both provided with temperature sensors. Real-time temperature data can be obtained through the temperature sensors, and the regulating valve can be controlled according to the temperature data.

[0009] Preferably, the first delivery pipe connects the bottom of the buffer tank to the finished product recovery column, the second delivery pipe connects the bottom of the rectification column to the finished product recovery column, and the second delivery pipe communicates with the first delivery pipe. A delivery pump is provided on the first delivery pipe. Some water and heavy components flow out from the bottom of the rectification column, and the amount of this part is less than that in the buffer tank. By mixing these two parts of water and heavy components, the VDF content in the wet material mainly composed of water and heavy components is increased, which facilitates the recovery of VDF by the finished product recovery column.

[0010] Preferably, the output end of the light component removal column is connected to the input end of the rectification column through a third delivery pipe, and the top of the finished product recovery column communicates with the third delivery pipe through a recovery pipe. The VDF obtained by the finished product recovery column is mixed with the material in the third delivery pipe through the recovery pipe and then enters the rectification column. Since the purity of the VDF obtained by the finished product recovery column is basically the same as that of the VDF in the third delivery pipe, direct recovery and use will not affect the purity of the VDF produced by the rectification column, and the production ratio can be further increased.

[0011] Preferably, an intermediate tank is provided between the liquefaction condenser and the light component removal column. The input end of the intermediate tank is connected to the output end of the liquefaction condenser, and the output end of the intermediate tank is connected to the input end of the light component removal column. It is used to store the liquefied material.

[0012] Preferably, the top of the buffer tank is connected to the liquefaction condenser through a fourth delivery pipe, and an air extraction device is provided on the fourth delivery pipe. The air extraction device can smoothly suck the gaseous material to the liquefaction condenser, improve the speed of the gaseous material entering the liquefaction condenser, and the flow rate of the gaseous material can be changed by changing the power of the air extraction device.

[0013] Preferably, a flow meter is provided on the fourth delivery pipe, and the flow meter is located between the air extraction device and the fourth delivery pipe. The power of the air extraction device is adjusted according to the data of the flow meter.

[0014] Preferably, a second regulating valve is provided on the fourth delivery pipe, and the second regulating valve is located between the air extraction device and the flow meter. The second regulating valve can also assist the air extraction device to change the flow rate of the gaseous material.

[0015] Compared with the prior art, the beneficial effects of the present utility model are as follows: After the material is preliminarily processed by the material condenser and the buffer tank, the purity of the VDF entering the rectification column is improved, so as to realize the production of VDF with a purity of more than 99.999%. The water content in the material entering the rectification column is reduced, the ice blockage phenomenon of the rectification column is eliminated, the stable operation of the system is prevented from being affected, and at the same time, the production capacity of the rectification column per unit time can be improved. Description of the Drawings

[0016] Figure 1 It is a schematic structural diagram of Embodiment 1 of a vinylidene fluoride production system of the present utility model;

[0017] Figure 2 It is a schematic structural diagram of Embodiment 2 of a vinylidene fluoride production system of the present utility model;

[0018] Figure 3 It is a schematic structural diagram of Embodiment 3 of a vinylidene fluoride production system of the present utility model. Detailed implementation manners

[0019] The drawings are only for illustrative purposes and should not be construed as a limitation of this patent; to better illustrate this embodiment, some components in the drawings may be omitted, enlarged or reduced, and do not represent the dimensions of the actual product; for those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted. The positional relationships described in the drawings are only for illustrative purposes and should not be construed as a limitation of this patent.

[0020] In the drawings of the embodiments of the present utility model, the same or similar reference numerals correspond to the same or similar components; in the description of the present utility model, it should be understood that if there are terms such as "upper", "lower", "left", "right", "long", "short", etc. indicating the orientation or positional relationship, they are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, the terms describing the positional relationship in the drawings are only for illustrative purposes and should not be construed as a limitation of this patent. For those of ordinary skill in the art, the specific meanings of the above terms can be understood according to specific circumstances.

[0021] The technical solutions of the present utility model will be further specifically described below through specific embodiments in conjunction with the drawings:

[0022] Embodiment 1

[0023] As Figure 1Shown is Embodiment 1 of a vinylidene fluoride production system, including a liquefaction condenser 1, a de-light tower 2 connected to the output end of the liquefaction condenser 1, a rectification tower 3 connected to the output end of the de-light tower 2, a finished product recovery tower 4 connected to the bottom of the rectification tower 3, a venting tower 5 connected to the bottom of the finished product recovery tower 4, and a raw material recovery tower 6 connected to the bottom of the venting tower 5; also including a material condenser 7 and a buffer tank 8 connected to the output end of the material condenser 7. The top of the buffer tank 8 is connected to the liquefaction condenser 1, and the bottom of the buffer tank 8 is connected to the finished product recovery tower 4. The de-light tower 2, the rectification tower 3, the finished product recovery tower 4, the venting tower 5, and the raw material recovery tower 6 are all connected through conveying pipes. Among them, it can be gravity-fed or pumped by a pump body. Valves are installed on all the conveying pipes, and the pump body or valves are not shown in the figure.

[0024] Specifically, the material condenser 7 and the buffer tank 8 are both provided with regulating valves for controlling the refrigerant inflow. Through the regulating valves, the temperatures of the material condenser 7 and the buffer tank 8 can be adjusted to better separate gaseous VDF and water from the heavy components. Among them, keeping the temperature of the buffer tank 8 at a relatively low temperature, such as 0 - 20 degrees Celsius, can gasify the VDF mixed in the water and heavy components at the bottom of the buffer tank 8 again, and can reduce the processing volume of the finished product recovery tower 4. The material condenser 7 and the buffer tank 8 are both provided with temperature sensors. By obtaining real-time temperature data through the temperature sensors, the regulating valves can be controlled according to the temperature data.

[0025] Among them, the first conveying pipe 9 connecting the bottom of the buffer tank 8 to the finished product recovery tower 4, and the second conveying pipe 10 connecting the bottom of the rectification tower 3 to the finished product recovery tower 4, and the second conveying pipe 10 communicates with the first conveying pipe 9. A conveying pump is provided on the first conveying pipe 9. Some water and heavy components flow out from the bottom of the rectification tower 3, and the amount of this part is less than that of the buffer tank 8. By mixing these two parts of water and heavy components, the VDF content in the wet material mainly composed of water and heavy components can be increased, which is convenient for the finished product recovery tower 4 to recover VDF.

[0026] Working principle of this embodiment: The material with a VDF purity of 80% is transported to the material condenser 7. Through the action of the material condenser 7, the water and heavy components in the material are liquefied, while VDF remains in a gaseous state. The liquefied water and heavy components enter the bottom of the buffer tank 8, and the gaseous material accumulates at the top of the buffer tank 8. The gaseous material mainly contains VDF. And due to the action of the material condenser 7, after the water and heavy components in the material are removed, the gaseous material is in a dry material state and the VDF purity reaches 98%. This part of the gaseous VDF enters the liquefaction condenser 1, where the gaseous VDF is liquefied and then enters the light component removal tower 2 to remove light components, and then enters the rectification tower 3 for rectification. Since the purity of the VDF entering the rectification tower has reached 98%, the rectification effect of the rectification tower 3 is further improved. Therefore, VDF with a purity of 99.999% is taken out from the top of the rectification tower 3, and the heavy components in the bottom of the rectification tower 3 enter the VDF recovery tower to recover a small amount of VDF, and then enter the venting tower 5 to vent the intermediate components between the finished VDF and the raw material R142b, and then enter the raw material recovery tower 6 to recover the raw material R142b from the top. The bottom of the raw material recovery tower 6 discharges the residual liquid. Since the moisture in the material has been separated from the gaseous VDF at the buffer tank 8, the water content in the material entering the rectification tower 3 is reduced to less than 100 ppm, and no visible water can be formed, eliminating the ice blockage phenomenon in the rectification tower 3; at the same time, the material input amount of the rectification tower 3 is limited, because if the material contains more moisture, the amount of VDF that can be produced per unit time will be less, and when the moisture content decreases, the amount of VDF produced per unit time will increase, thereby improving the production capacity of the rectification tower 3. And the water and heavy components enter the finished product recovery tower 4 through the bottom of the buffer tank 8 to further recover VDF from this part of the material.

[0027] Beneficial effects of this embodiment: After the material is preliminarily processed by the material condenser 7 and the buffer tank 8, the purity of the VDF entering the rectification tower 3 is improved, so as to realize the mass production of VDF with a purity of more than 99.999%. The water content in the material entering the rectification tower 3 is reduced, eliminating the ice blockage phenomenon in the rectification tower 3 and avoiding affecting the stable operation of the system. At the same time, the production capacity of the rectification tower 3 per unit time can also be improved. If the production capacity is neither reduced nor increased, the volume of the rectification tower can be reduced. For example, when calculating the annual production of 8000 tons of VDF, the diameter of the rectification tower needs to be more than 700 mm, and the required rectification tower is relatively large. However, if this solution is adopted, the diameter of the rectification tower only needs to be more than 500 mm, which can reduce the equipment cost.

[0028] Embodiment 2

[0029] Such as Figure 2Shown is Embodiment 2 of a vinylidene fluoride production system. The first transfer pipe 9 connects the bottom of the buffer tank 8 to the finished product recovery column 4, and the second transfer pipe 10 connects the bottom of the rectification column 3 to the finished product recovery column 4. The second transfer pipe 10 communicates with the first transfer pipe 9. A transfer pump (not shown in the figure) is provided on the first transfer pipe 9. Some water and heavy components flow out from the bottom of the rectification column 3, and the amount of this part is less than that of the buffer tank 8. By mixing these two parts of water and heavy components, the VDF content in the wet material mainly composed of water and heavy components is increased, facilitating the recovery of VDF by the finished product recovery column 4.

[0030] Specifically, the output end of the light component removal column 2 is connected to the input end of the rectification column 3 through the third transfer pipe 11, and the top of the finished product recovery column 4 is communicated with the third transfer pipe 11 through the recovery pipe 401. The VDF obtained by the finished product recovery column 4 is mixed with the material in the third transfer pipe 11 through the recovery pipe and then enters the rectification column 3. Since the purity of the VDF obtained by the finished product recovery column 4 is basically the same as that of the VDF in the third transfer pipe 11, directly recycling and using it will not affect the purity of the VDF produced by the rectification column 3, and can further improve the output ratio.

[0031] Among them, an intermediate tank 12 is provided between the liquefaction condenser 1 and the light component removal column 2. The input end of the intermediate tank 12 is connected to the output end of the liquefaction condenser 1, and the output end of the intermediate tank 12 is connected to the input end of the light component removal column 2. It is used to store the liquefied material.

[0032] In this embodiment, the first transfer pipe, the second transfer pipe, and the third transfer pipe are themselves transfer pipes connecting different components, and only need to be named separately for convenient description.

[0033] The remaining features and working principles of this embodiment are the same as those of Embodiment 1.

[0034] Embodiment 3

[0035] As Figure 3Shown is Embodiment 3 of a vinylidene fluoride production system. The top of the buffer tank 8 is connected to the liquefaction condenser 1 through the fourth conveying pipe 13, and an air extraction device 14 is provided on the fourth conveying pipe 13. A flow meter 15 is provided on the fourth conveying pipe 13, and the flow meter 15 is located between the air extraction device 14 and the fourth conveying pipe 13. A regulating valve is provided on the fourth conveying pipe 13, and the regulating valve is located between the air extraction device 14 and the flow meter 15. The air extraction device 14 can smoothly suck the gaseous material to the liquefaction condenser 1, improving the speed of the gaseous material entering the liquefaction condenser 1. By changing the power of the air extraction device 14, the flow rate of the gaseous material can also be changed. According to the production plan or the processing capacity of the liquefaction condenser 1, the flow rate of the fourth conveying pipe 13 is set correspondingly and detected by the flow meter 15. When the flow rate is insufficient, the power of the air extraction device 14 can be increased. When the speed needs to be reduced, the opening degree of the regulating valve and the power of the air extraction device 14 can be changed. The flow rate is adjusted in two different ways, and the adjustment method is flexible and there is no need to worry about the damage of a single device.

[0036] The remaining features and working principles of this embodiment are the same as those of Embodiment 1.

[0037] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, rather than limitations on the implementation manners of the present invention. For those of ordinary skill in the art, other different forms of changes or variations can be made on the basis of the above description. It is not necessary and impossible to enumerate all the implementation manners here. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the claims of the present invention.

Claims

1. A vinylidene fluoride production system, comprising a liquefaction condenser (1), a lightness removal tower (2) connected to the output end of the liquefaction condenser (1), a distillation tower (3) connected to the output end of the lightness removal tower (2), a finished product recovery tower (4) connected to the tower bottom of the distillation tower (3), a venting tower (5) connected to the tower bottom of the finished product recovery tower (4), and a raw material recovery tower (6) connected to the tower bottom of the venting tower (5), characterized in that: It also includes a material condenser (7) and a buffer tank (8) connected to the output end of the material condenser (7), the top of the buffer tank (8) is connected to the liquefaction condenser (1), and the bottom of the buffer tank (8) is connected to the finished product recovery tower (4).

2. A vinylidene fluoride production system according to claim 1, characterized in that: The material condenser (7) and the buffer tank (8) are both provided with a first regulating valve for controlling the inflow of refrigerant.

3. A vinylidene fluoride production system according to claim 2, characterized in that: The material condenser (7) and the buffer tank (8) are both provided with temperature sensors.

4. A vinylidene fluoride production system according to claim 1, characterized in that: The bottom of the buffer tank (8) is connected to the finished product recovery tower (4) via a first delivery pipe (9), the bottom of the distillation tower (3) and the finished product recovery tower (4) are connected via a second delivery pipe (10), and the second delivery pipe (10) is connected to the first delivery pipe (9).

5. A vinylidene fluoride production system according to claim 4, characterized in that: The first delivery pipe (9) is provided with a delivery pump.

6. A vinylidene fluoride production system according to claim 1, characterized in that: The output end of the light-removal tower (2) is connected to the input end of the distillation tower (3) via a third delivery pipe (11), and the top end of the finished product recovery tower (4) is connected to the third delivery pipe (11) via a recovery pipe (401).

7. A vinylidene fluoride production system according to claim 1, characterized in that: An intermediate tank (12) is arranged between the liquefaction condenser (1) and the lightness removal tower (2); the input end of the intermediate tank (12) is connected to the output end of the liquefaction condenser (1), and the output end of the intermediate tank (12) is connected to the input end of the lightness removal tower (2).

8. A vinylidene fluoride production system according to claim 1, characterized in that: The top of the buffer tank (8) is connected to the liquefaction condenser (1) via a fourth delivery pipe (13), and a gas extraction device (14) is provided on the fourth delivery pipe (13).

9. A vinylidene fluoride production system according to claim 8, characterized in that: The fourth delivery pipe (13) is provided with a flow meter (15), and the flow meter (15) is located between the air extraction device (14) and the fourth delivery pipe (13).

10. A vinylidene fluoride production system according to claim 9, characterized in that: The fourth delivery pipe (13) is provided with a second regulating valve (16), and the second regulating valve (16) is located between the air extraction device (14) and the flow meter (15).

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