Purification rectifying tower for increasing heavy components of vinylene carbonate

Abstract

The utility model relates to a rectifying tower, in particular to a vinylene carbonate heavy component increasing and purifying rectifying tower. Comprising a VC crude product feeding tank, a scraper evaporator, a VC light component removal tower, a VC heavy component removal tower and a VC purification tower which are sequentially connected through a pipeline, the VC crude product feeding tank is used for storing a VC material crude product, the scraper evaporator is used for removing heavy component impurities in the VC material crude product through coarse distillation, the VC material subjected to coarse distillation enters the VC light component removal tower, the VC light component removal tower is used for removing light component impurities in the VC material, and the VC purification tower is used for purifying the VC material. The VC material after light component removal enters the VC heavy component removal tower, the VC heavy component removal tower performs heavy component removal to produce a VC product, and the VC purification tower is used for purifying heavy component impurities of the VC material removed by the VC heavy component removal tower. Through the purification tower and related equipment, heavy component materials are independently distilled, the recovery rate is increased, the operation cost is reduced, and maximum-efficiency recovery of products is realized.

Description

Technical Field

[0001] The utility model relates to a distillation tower, in particular to a distillation tower for adding and purifying heavy components of vinylene carbonate. Background Art

[0002] Vinylene carbonate (VC) is an organic compound that can be used as a novel organic film-forming additive and overcharge protection additive for lithium-ion batteries. It exhibits excellent high- and low-temperature performance and anti-flatulence properties, thereby increasing battery capacity and cycle life. The production of VC typically requires a distillation column. With the development of society, many new distillation columns have been introduced to the market.

[0003] The existing distillation tower suffers from a low vinylene carbonate recovery rate. The heavy fraction from the de-weighting tower enters the scraper evaporator directly, with a purity of 50%, which differs from the 75% purity of the crude product. When the previously processed material enters the scraper evaporator again, some impurities that could be evaporated are unable to be removed, leading to their accumulation within the system. This, in turn, results in a purity of the de-weighting tower overhead product below 99.5%, ultimately impacting the production capacity and yield of the downstream crystallization unit. The traditional method is to reduce the scraper temperature when processing this heavy fraction to avoid the accumulation of intermediate components, but this results in a lower overall product recovery rate. Utility Model Content

[0004] In view of the above problems, the purpose of the present invention is to provide a distillation tower for adding and purifying vinylene carbonate heavy components, so as to solve the problem of low recovery rate of existing distillation towers.

[0005] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0006] The utility model provides a vinylene carbonate heavy component increasing and purification distillation tower, comprising a VC crude product feed tank, a scraper evaporator, a VC light component removal tower, a VC heavy component removal tower and a VC purification tower which are sequentially connected through pipelines, wherein the VC crude product feed tank is used for storing crude VC material, the scraper evaporator is used for roughly distilling and removing heavy component impurities in the crude VC material, the VC material after roughly distilling enters the VC light component removal tower, the VC light component removal tower is used for removing light component impurities in the VC material, the VC material after light component removal enters the VC heavy component removal tower, the VC heavy component removal tower removes heavy components to produce VC products, and the VC purification tower is used for purifying the heavy component impurities of the VC material removed by the VC heavy component removal tower.

[0007] A VC deweighting tower reboiler, a VC heavy component intermediate tank and a VC purification tower distillation kettle are provided between the VC deweighting tower and the VC purification tower, which are connected in sequence;

[0008] The bottom of the VC deweighting tower is connected to the top of the VC deweighting tower reboiler through a VC deweighting tower kettle pump. The bottom head of the VC deweighting tower reboiler has two discharge ports, namely a gas phase outlet located on the side and a liquid phase outlet located at the bottom. The gas phase outlet is connected to the bottom of the VC deweighting tower, and the liquid phase outlet is connected to the bottom of the VC deweighting tower and the top of the VC heavy component intermediate tank through two pipelines. A regulating valve is provided on the pipeline to the VC heavy component intermediate tank; the bottom of the VC heavy component intermediate tank is connected to the top of the VC purification tower distillation kettle through a VC heavy component pump. The VC purification tower distillation kettle vaporizes the VC contained in the heavy component impurities and allows it to enter the VC purification tower.

[0009] The top of the VC heavy component intermediate tank is connected to the vacuum pipeline c; the top of the VC heavy component intermediate tank is connected to the bottom of the scraper evaporator through the purification pipeline, and the heavy component impurities in the crude VC material roughly distilled off by the scraper evaporator directly enter the VC heavy component intermediate tank.

[0010] A stirring paddle is provided in the distillation kettle of the VC purification tower, and a discharge port is provided at the bottom of the distillation kettle of the VC purification tower.

[0011] The top of the VC purification tower is connected to the VC purification tower condenser, the VC purification tower reflux tank and the VC purification tower reflux pump in sequence. The outlet of the VC purification tower reflux pump is connected to the top of the VC purification tower reflux tank, the top of the VC purification tower and the VC crude product feed tank through three reflux pipelines. Control valves are provided on the three reflux pipelines. The top of the VC purification tower reflux tank is connected to the ultimate vacuum pipeline.

[0012] The bottom of the scraper evaporator is connected to the VC crude product waste intermediate tank, and the bottom of the VC crude product waste intermediate tank is connected to the incineration pipeline and the purification pipeline.

[0013] The scraper evaporator adopts a three-section steam jacket structure. The inlet of each steam jacket is provided with an inlet steam manual valve, through which the steam flow of each steam jacket structure is adjusted. A temperature measuring point is provided at the condensate outlet of each steam jacket.

[0014] The top of the VC light removal tower is connected to the VC light removal tower primary condenser, the VC light removal tower secondary condenser, the VC light component storage tank, the VC light component delivery pump and the upstream workshop recovery pipeline in sequence, and the VC light removal tower secondary condenser is connected to the vacuum pipeline a.

[0015] The bottom of the VC light removal tower is connected to the VC light removal tower kettle pump and the VC light removal tower reboiler in a closed loop in sequence, and the outlet of the VC light removal tower kettle pump is connected to the two feed ports of the VC heavy removal tower.

[0016] The top of the VC deweighting tower is connected to the VC deweighting tower condenser, the VC deweighting tower reflux tank and the VC deweighting tower reflux pump in sequence, and the outlet of the VC deweighting tower reflux pump is connected to the top of the VC deweighting tower and the product recovery pipeline; the VC deweighting tower condenser is connected to the vacuum pipeline b.

[0017] The advantages and beneficial effects of the present invention are as follows: the present invention provides a distillation tower for increasing the purification of vinylene carbonate heavy components. The crude VC material produced by the upstream workshop passes through a scraper evaporator. The heavy component impurities in the crude VC material enter the VC crude product bottom intermediate tank. The VC content of the heavy component impurities is analyzed. If the VC content is high, it is recycled to the VC purification tower. If the content is low, it is sent to the incineration station for incineration. The light component impurities in the VC material enter the VC light removal tower. The light component at the top of the VC light removal tower is returned to the upstream workshop for recycling. The heavy component at the bottom of the VC light removal tower enters the VC heavy removal tower. The heavy component at the bottom of the VC heavy removal tower is sent to the VC purification tower and sent to the incineration station for incineration. The light component at the top of the VC purification tower is returned to the VC crude product feed tank 2 for recycling. The utility model uses the purification tower and related equipment to separately distill the heavy component material. The purity of the distilled light component material is about 90%, which is much higher than the 75% of the crude product. In this way, the scraper evaporator can operate stably and the purity of the material at the top of the heavy removal tower can be stabilized at about 99.6%. The purity of the heavy components in the purification tower is less than 10%, which is directly listed as unrecoverable components and sent to the incinerator for treatment.

[0018] In order to solve the problem of low yield caused by fluctuation of scraper evaporator, the utility model also adds a new pipeline to go directly to the purification tower feed tank, which can continue to recycle, thus greatly improving the material yield. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of the structure of the utility model in which a purification distillation tower is added to the vinylene carbonate heavy component.

[0020] In the figure: 1-workshop feed pipeline, 2-VC crude product feed tank, 3-scraper evaporator, 4-VC crude product bottom intermediate tank, 5-incineration pipeline, 6-VC light component removal tower, 7-VC light component removal tower primary condenser, 8-VC light component removal tower secondary condenser, 9-vacuum pipeline a, 10-VC light component storage tank, 11-VC light component delivery pump, 12-upstream workshop recovery pipeline, 13-VC light component removal tower reboiler, 14-VC light component removal tower kettle pump, 15-VC heavy component removal tower, 16-VC heavy component removal tower condenser, 17 -Vacuum pipeline b, 18-VC deweighting tower reflux tank, 19-VC deweighting tower reflux pump, 20-VC product recovery pipeline, 21-VC deweighting tower kettle pump, 22-VC deweighting tower reboiler, 23-VC heavy component intermediate tank, 24-VC heavy component pump, 25-vacuum pipeline c, 26-VC purification tower distillation kettle, 27-VC purification tower, 28-VC purification tower condenser, 29-VC purification tower reflux tank, 30-VC purification tower reflux pump, 31-limit vacuum pipeline, 32-depurification pipeline. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0022] like Figure 1 As shown, the utility model provides a distillation tower for increasing and purifying the heavy component of vinylene carbonate, comprising a VC crude product feed tank 2, a scraper evaporator 3, a VC light removal tower 6, a VC weight removal tower 15 and a VC purification tower 27 connected in sequence by pipelines, wherein the VC crude product feed tank 2 is used to store crude VC material, the scraper evaporator 3 is used to roughly evaporate and remove heavy component impurities in the crude VC material, the VC material after rough distillation enters the VC light removal tower 6, the VC light removal tower 6 is used to remove light component impurities in the VC material, the VC material after light removal enters the VC weight removal tower 15, the VC weight removal tower 15 removes heavy components and outputs VC products, and the VC purification tower 27 is used to further purify the heavy component impurities of the VC material removed from the VC weight removal tower 15 for recycling.

[0023] like Figure 1 As shown, in the embodiment of the present invention, the scraper evaporator 3 is a crude product evaporator. The scraper evaporator 3 adopts a three-stage steam jacket structure. The inlet of each steam jacket is provided with an inlet steam manual valve. The steam flow of each steam jacket structure is adjusted by the inlet steam manual valve. A temperature measuring point is provided at the condensate outlet of each steam jacket.

[0024] In the embodiment of the present invention, the bottom of the scraper evaporator 3 is connected to the crude VC off-take intermediate tank 4, which is in turn connected to the incineration pipeline 5 and the purification pipeline 32. Heavy impurities roughly removed by the scraper evaporator 3 enter the crude VC off-take intermediate tank 4. The VC content of these heavy impurities is analyzed. If the VC content is high, it is sent to the VC purification tower 27 via the purification pipeline 32 for purification and recovery. If the VC content is low, it is sent to the incineration station via the incineration pipeline 5 for incineration.

[0025] In an embodiment of the present utility model, the VC delightening tower 6 has two feed ports at different heights. The top of the VC delightening tower 6 is connected to the VC delightening tower primary condenser 7, the VC delightening tower secondary condenser 8, the VC light component storage tank 10, the VC light component delivery pump 11 and the upstream workshop recovery pipeline 12 in sequence, and the VC delightening tower secondary condenser 8 is connected to the vacuum pipeline a9.

[0026] The bottom of the VC light removal tower 6 is connected in a closed loop with the VC light removal tower kettle pump 14 and the VC light removal tower reboiler 13 in sequence, and the outlet of the VC light removal tower kettle pump 14 is connected with two feed ports of the VC heavy removal tower 15.

[0027] In an embodiment of the present utility model, the top of the VC deweighting tower 15 is connected to the VC deweighting tower condenser 16, the VC deweighting tower reflux tank 18 and the VC deweighting tower reflux pump 19 in sequence, and the outlet of the VC deweighting tower reflux pump 19 is connected to the top of the VC deweighting tower 15 and the product recovery pipeline 20; the VC deweighting tower condenser 16 is connected to the vacuum pipeline b17.

[0028] Furthermore, a VC deweighting tower reboiler 22, a VC heavy component intermediate tank 23 and a VC purification tower distillation kettle 26 are provided between the VC deweighting tower 15 and the VC purification tower 27. The bottom of the VC deweighting tower 15 is connected to the top of the VC deweighting tower reboiler 22 through a VC deweighting tower kettle pump 21. The bottom head of the VC deweighting tower reboiler 22 has two discharge ports, which are a gas phase outlet located on the side and a liquid phase outlet located at the bottom. The gas phase outlet is connected to the VC deweighting tower 15. 5, and the liquid phase outlet is connected to the bottom of the VC deweighting tower 15 and the top of the VC heavy component intermediate tank 23 through two pipelines respectively. A regulating valve is provided on the pipeline to the VC heavy component intermediate tank to control the flow rate, and the excess liquid phase material returns to the VC deweighting tower 15; the bottom of the VC heavy component intermediate tank 23 is connected to the top of the VC purification tower distillation kettle 26 through the VC heavy component pump 24, and the VC purification tower distillation kettle 26 vaporizes the VC contained in the heavy component impurities and enters the VC purification tower 27.

[0029] Furthermore, the top of the VC heavy component intermediate tank 23 is connected to the vacuum pipeline c25. A stirring blade is provided in the VC purification tower still 26, and a discharge port is provided at the bottom of the VC purification tower still 26, which is connected to the incineration pipeline 5 through a pipeline.

[0030] In an embodiment of the present utility model, the top of the VC purification tower 27 is connected to the VC purification tower condenser 28, the VC purification tower reflux tank 29 and the VC purification tower reflux pump 30 in sequence, and the outlet of the VC purification tower reflux pump 30 is connected to the top of the VC purification tower reflux tank 29, the top of the VC purification tower 27 and the VC crude product feed tank 2 through three reflux pipelines. Control valves are provided on the three reflux pipelines, and the top of the VC purification tower reflux tank 29 is connected to the limit vacuum pipeline 31.

[0031] The utility model provides a vinylene carbonate heavy component adding and purification distillation tower, and its VC distillation process is as follows:

[0032] Crude VC material from the upstream workshop and recovered from VC purification tower 27 in this workshop enter crude VC feed tank 2 (20 cubic meters capacity). The material in crude VC feed tank 2 passes through an outlet regulating valve and enters scraper evaporator 3 (15 square meters heat exchange area). Scraper evaporator 3 utilizes a three-stage steam jacket. Temperature measuring points are located at each condensate outlet. Manual steam inlet valves regulate the steam flow rate within each section to maintain uniform heating of the material within the scraper, preventing local overheating and potentially affecting the material. Feedback from the heavy component temperature measuring point at the bottom of scraper evaporator 3 provides steam regulation. The final temperature at the three steam condensate temperature measuring points is controlled as follows: 90°C, 95°C, and 100°C, with a bottom temperature of 98°C. Unvaporized heavy component impurities in scraper evaporator 3 pass through the bottom outlet and enter crude VC waste intermediate tank 4. The material in crude VC waste intermediate tank 4 can be directly incinerated in the incinerator. The vaporized material in scraper evaporator 3 enters VC de-lightness tower 6 through an overhead pipeline. VC de-lightness tower 6 has a diameter of 600 mm, a height of 28 meters, a five-stage packed tower, and a vacuum level of -80 kPa. VC de-lightness tower 6 utilizes two feed locations, one above and one below. Adjusting the opening of the two manual feed valves allows for flexible adjustment of feed load and effective energy balance. The VC de-lightening tower primary condenser 7 (heat exchange area 150 square meters) at the top of the VC de-lightening tower 6 is directly installed on the top of the VC de-lightening tower 6. The reflux rate is controlled by adjusting the circulating water flow rate. The main condensed material is VC. The advantage is that the design of the reflux pump can be reduced, and energy consumption can be effectively reduced. The remaining material is in the VC de-lightening tower secondary condenser 8 (heat exchange area 30 square meters, cooling medium is -20 degree cold salt). The VC de-lightening tower secondary condenser 8 adopts the bottom head side feeding and the top head vacuuming form. The condensate is produced in the middle of the bottom head. The advantage of this method is that it can effectively reduce the VC de-lightening tower primary condenser 7. The operating error causes the VC material to be brought out. Even if VC material enters the VC de-lightening tower secondary condenser 8, the material can be melted by introducing steam (steam is not used normally, and an eight-shaped blind plate is used for isolation). The vertical type can ensure that the discharge is clean enough, and a small amount of steam condensate entering the cold salt system does not affect the overall cold salt system. The light constituent material enters VC light constituent storage tank 10 after condensation, is then delivered to upstream workshop for recycling with VC light constituent delivery pump 11 and upstream workshop recovery pipeline 12.The tower bottom of VC light constituent removal column 6 adopts the mode (circulation capacity 40 tons / hour) of circulating pump forced circulation, VC light constituent removal column reboiler 13 (heat exchange area 30 flat, tower bottom temperature is controlled at about 80 degree) adopts vertical top feeding, such benefit can effectively avoid the situation that material is overheated in VC light constituent removal column reboiler 13, overheating can cause material generation side reaction, reduce system yield, also can affect heat exchange effect after coking, need frequent disassembly and cleaning simultaneously.The bottom end shell of VC light constituent removal column reboiler 13 has two discharge ports, is respectively positioned at the gas phase outlet of side, is positioned at the liquid phase outlet of bottom.The advantage that gas-liquid two-phase separates is exactly can better separate material, indirectly improves the effect of rectifying tower.

[0033] Material is transferred from the bottom of VC de-lightening tower 6 to VC de-weighting tower 15. VC de-weighting tower 15 has a diameter of 600 mm, a height of 22 meters, a five-stage packed tower, and a vacuum level of -95 kPa. VC de-weighting tower 15 also utilizes two feed inlets, again due to the selection of manual valve openings based on feed load and energy consumption. The VC material passes through VC de-weighting tower condenser 16 (heat exchange area of 150 square meters) in VC de-weighting tower 15, where it is cooled to 30°C before entering VC de-weighting tower reflux tank 18. VC de-weighting tower condenser 16 is horizontal with a 1-degree inclination. The discharge head has a horizontal section, where the discharge port and vacuum port are located, ensuring no liquid accumulation within the heat exchanger. The circulating water inlet is located in the high-temperature zone of the material, while the return water is located in the low-temperature zone toward the material outlet. This prevents crystallization near the circulating water inlet during winter when the circulating water temperature is low. Furthermore, due to the 1-degree inclination, a drain outlet is required at the lowest point of the shell. Part of the VC in the VC de-weighting tower reflux tank 18 flows to the VC de-weighting tower 15 to provide reflux for the VC de-weighting tower 15, and part of it returns to the VC de-weighting tower reflux tank 18. Due to the large design load, the VC de-weighting tower reflux pump 19 can better ensure that it operates at the rated flow rate at low load, and the other route sends the product to the crystallization unit. The bottom of the VC de-weighting tower 15 adopts a circulating pump forced circulation method (circulation rate 60 tons / hour), and the VC de-weighting tower reboiler 22 (heat exchange area 45 square meters, tower bottom temperature controlled at about 90 degrees) adopts vertical top feeding. This has the advantage of effectively avoiding overheating of the material in the VC de-weighting tower reboiler 22. Overheating can cause side reactions in the material, reduce the system yield, and affect the heat exchange effect after coking. At the same time, it requires frequent disassembly and cleaning. The bottom head of the VC de-weighting tower reboiler 22 has two discharge ports, namely the gas phase outlet on the side and the liquid phase outlet at the bottom. There is a VC heavy component intermediate tank 23 at the lower part of the liquid phase outlet horizontal pipe (gravity flow enters this tank first). According to the sampling results at the bottom of the tower, a regulating valve is used to control the external collection amount, and the remaining part is returned to the VC de-weighting tower 15.

[0034] The VC heavy component intermediate tank 23 is pumped by VC heavy component pump 24 to the VC purification tower still 26 (10 cubic meters). The agitator is turned on, and steam is introduced into the jacket of the VC purification tower still 26, achieving a bottom temperature of approximately 90°C. This vaporizes the VC and sends it to the VC purification tower 27, which has a diameter of 300 mm, a height of 15 meters, and a three-stage packed tower. After condensation in the VC purification tower condenser 28 at the top of VC purification tower 27, the VC enters the VC purification tower reflux tank 29. This condenser 28 has the same structure as the de-weighting tower top condenser, with a heat exchange area of 30 square meters. The top of the VC purification tower reflux tank 29 is connected to an independent ultimate vacuum system. Due to the low amount of non-condensable gases, the ultimate vacuum can be maintained effectively. Compared to the bottom of the de-weighting tower, at the same bottom temperature of approximately 90°C, the VC vaporizes better, thereby increasing the recovery rate. A portion of the recovered crude VC is refluxed to the VC purification tower 27, and a portion is returned to the crude VC feed tank 2 for recycling. The remaining residue in the distillation kettle 26 of the VC purification tower is sampled and analyzed. When the content is extremely low, it is directly incinerated.

[0035] In the embodiment of the present invention, crude VC (vinylene carbonate) (containing approximately 75% VC) is crudely distilled in a scraper evaporator 3 to remove heavy impurities, then passed through a VC de-weighting tower 6 to remove light impurities. The top of the VC de-weighting tower 15 produces a 99.5% pure product, while the bottom of the tower produces 50% pure heavy components. Because the bottom product of the VC de-weighting tower 15 contains too high a VC content, it is recovered through a VC purification tower 27 to increase the recovery rate, reduce operating costs, and achieve maximum product recovery efficiency.

[0036] The above description is only an embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modification, equivalent replacement, improvement, expansion, etc. made within the spirit and principle of the present invention are included in the scope of protection of the present invention.

Claims

1. A vinylene carbonate heavy component adding and purification distillation tower, characterized in that: The invention comprises a VC crude product feed tank (2), a scraper evaporator (3), a VC light-removing tower (6), a VC weight-removing tower (15) and a VC purification tower (27) which are sequentially connected through pipelines, wherein the VC crude product feed tank (2) is used to store VC crude product, the scraper evaporator (3) is used to roughly evaporate and remove heavy component impurities in the VC crude product, the VC material after rough evaporation enters the VC light-removing tower (6), the VC light-removing tower (6) is used to remove light component impurities in the VC material, the VC material after light-removal enters the VC weight-removing tower (15), the VC weight-removing tower (15) removes heavy component impurities to produce VC products, and the VC purification tower (27) is used to purify the heavy component impurities of the VC material removed by the VC weight-removing tower (15).

2. The vinylene carbonate heavy component adding and purification distillation tower according to claim 1, characterized in that: A VC deweighting tower reboiler (22), a VC heavy component intermediate tank (23) and a VC purification tower still (26) are provided between the VC deweighting tower (15) and the VC purification tower (27), which are connected in sequence; The bottom of the VC deweighting tower (15) is connected to the top of the VC deweighting tower reboiler (22) through a VC deweighting tower kettle pump (21). The bottom head of the VC deweighting tower reboiler (22) has two discharge ports, namely a gas phase outlet located on the side and a liquid phase outlet located at the bottom. The gas phase outlet is connected to the bottom of the VC deweighting tower (15), and the liquid phase outlet is connected to the bottom of the VC deweighting tower (15) and the top of the VC heavy component intermediate tank (23) through two branch pipelines. A regulating valve is provided on the pipeline to the VC heavy component intermediate tank (23); the bottom of the VC heavy component intermediate tank (23) is connected to the top of the VC purification tower distillation kettle (26) through a VC heavy component pump (24). The VC purification tower distillation kettle (26) vaporizes the VC contained in the heavy component impurities and allows it to enter the VC purification tower (27).

3. The vinylene carbonate heavy component adding and purification distillation tower according to claim 2, characterized in that: The top of the VC heavy component intermediate tank (23) is connected to the vacuum pipeline c (25); the top of the VC heavy component intermediate tank (23) is connected to the bottom of the scraper evaporator (3) through the purification pipeline (32), and the heavy component impurities in the crude VC material roughly evaporated by the scraper evaporator (3) directly enter the VC heavy component intermediate tank (23).

4. The vinylene carbonate heavy component adding and purification distillation tower according to claim 2, characterized in that: A stirring paddle is provided in the VC purification tower distillation kettle (26), and a discharge port is provided at the bottom of the VC purification tower distillation kettle (26).

5. The vinylene carbonate heavy component adding and purification distillation tower according to claim 1, characterized in that: The top of the VC purification tower (27) is connected to the VC purification tower condenser (28), the VC purification tower reflux tank (29) and the VC purification tower reflux pump (30) in sequence. The outlet of the VC purification tower reflux pump (30) is connected to the top of the VC purification tower reflux tank (29), the top of the VC purification tower (27) and the VC crude product feed tank (2) through three reflux pipelines, respectively. Control valves are provided on the three reflux pipelines. The top of the VC purification tower reflux tank (29) is connected to the ultimate vacuum pipeline (31).

6. The vinylene carbonate heavy component adding and purification distillation tower according to claim 1, characterized in that: The bottom of the scraper evaporator (3) is connected to the VC crude product waste intermediate tank (4), and the bottom of the VC crude product waste intermediate tank (4) is connected to the incineration pipeline (5) and the purification pipeline (32).

7. The vinylene carbonate heavy component adding and purification distillation tower according to claim 1, characterized in that: The scraper evaporator (3) adopts a three-section steam jacket structure. The inlet of each steam jacket is provided with an inlet steam manual valve. The steam flow of each steam jacket structure is adjusted by the inlet steam manual valve. The condensate outlet of each steam jacket is provided with a temperature measuring point.

8. The vinylene carbonate heavy component adding and purification distillation tower according to claim 1, characterized in that: The top of the VC light removal tower (6) is connected in sequence to a VC light removal tower primary condenser (7), a VC light removal tower secondary condenser (8), a VC light component storage tank (10), a VC light component delivery pump (11) and an upstream workshop recovery pipeline (12), and the VC light removal tower secondary condenser (8) is connected to a vacuum pipeline a (9).

9. The vinylene carbonate heavy component adding and purification distillation tower according to claim 1, characterized in that: The bottom of the VC light removal tower (6) is connected to the VC light removal tower kettle pump (14) and the VC light removal tower reboiler (13) in a closed loop in sequence, and the outlet of the VC light removal tower kettle pump (14) is connected to the two feed ports of the VC heavy removal tower (15).

10. The vinylene carbonate heavy component adding and purification distillation tower according to claim 1, characterized in that: The top of the VC deweighting tower (15) is connected to a VC deweighting tower condenser (16), a VC deweighting tower reflux tank (18) and a VC deweighting tower reflux pump (19) in sequence, and the outlet of the VC deweighting tower reflux pump (19) is connected to the top of the VC deweighting tower (15) and a product recovery pipeline (20); the VC deweighting tower condenser (16) is connected to a vacuum pipeline b (17).

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