Efficient recovery system for vinyl chloride-containing waste alkaline water in synthesis of vinyl chloride by calcium carbide method

Abstract

The utility model provides an efficient recovery system for vinyl chloride-containing waste alkaline water in vinyl chloride synthesis by a calcium carbide method, belongs to the technical field of waste alkaline water recovery, solves the problem that the waste alkaline water cannot be efficiently recovered in the vinyl chloride synthesis process, and comprises a waste water tank which is connected with a waste water stripping tower and a vinyl chloride gas holder, the bottom of the wastewater stripping tower is communicated with a reboiler, the reboiler is connected with a wastewater cooler, a wastewater neutralizing tank, a primary sedimentation tank, a secondary sedimentation tank, a sludge tank and a clean water tank, the clean water tank is respectively connected with two activated carbon filters, and the activated carbon filters are connected with an RO water inlet tank, a reverse osmosis device, an RO water producing tank, a plurality of mixed beds and a circulating water tank. And the reverse osmosis device is also connected with the primary sedimentation tank. According to the utility model, the recycling of the waste alkaline water containing the vinyl chloride is realized, meanwhile, the recycling of the vinyl chloride is realized, the production operation cost is reduced, the zero discharge of the waste water is realized, and good economic benefits and social benefits are obtained.

Description

Technical Field

[0001] The utility model belongs to the technical field of waste alkaline water recovery, and in particular relates to a high-efficiency recovery system for waste alkaline water containing vinyl chloride in vinyl chloride synthesis by a calcium carbide process. Background Art

[0002] In the production of vinyl chloride by the calcium carbide method, hydrogen chloride is reacted with acetylene to produce vinyl chloride. This process will produce acidic by-products, such as residual hydrogen chloride, carbon dioxide and other acidic media. Alkaline washing neutralizes these acidic substances with sodium hydroxide solution to ensure product purity. Alkaline washing of vinyl chloride is not only a purification process, but also a key link to ensure production continuity, environmental protection, economic benefits, and improve product quality and equipment life.

[0003] Alkali washing is a chemical absorption operation. During the absorption process, a chemical reaction occurs. Carbon dioxide and trace amounts of hydrogen chloride can be removed by alkali washing. An alkali washing tower is usually set up in the device. A dilute solution of sodium hydroxide is used as a chemical absorbent. The concentration of sodium hydroxide solution is 10%-15%. The crude vinyl chloride gas is washed to neutrality and then sent to subsequent production. When the alkali solution concentration is detected to be less than 10% or sodium carbonate is ≥5%, fresh alkali solution needs to be replaced. Usually, the waste alkali solution needs to be discharged directly to the sewage treatment process. Direct discharge has the following problems:

[0004] 1. Vinyl chloride-containing alkali liquor contains high concentrations of sodium chloride, organic matter, and possibly unreacted vinyl chloride monomer. Direct discharge of the liquor into a sewage treatment plant will cause eutrophication of the water body, inhibit the growth of aquatic organisms, and affect the ecological balance of the water treatment process.

[0005] 2. Since vinyl chloride is a flammable and explosive gas, discharging it into a sewage treatment plant carries the risk of flash explosion, posing a significant safety risk.

[0006] 3. In the production of polyvinyl chloride, vinyl chloride is a valuable raw material. If it is not recycled, it will cause serious waste. At the same time, the treatment and discharge of wastewater will cause waste of water resources. Utility Model Content

[0007] The utility model aims to provide a high-efficiency recovery system for waste alkaline water containing vinyl chloride in the synthesis of vinyl chloride by the calcium carbide method, so as to solve the problem that the waste alkaline water cannot be efficiently recovered in the process of vinyl chloride synthesis.

[0008] The technical solution of the utility model is: a high-efficiency recovery system for waste alkaline water containing vinyl chloride in the synthesis of vinyl chloride by the calcium carbide process, comprising a wastewater tank, the wastewater tank is connected to a wastewater stripping tower, the top of the wastewater stripping tower is connected to a vinyl chloride gas holder, the bottom of the wastewater stripping tower is connected to a reboiler, the reboiler is sequentially connected to a wastewater cooler, a wastewater neutralization tank, a primary sedimentation tank and a secondary sedimentation tank, the bottoms of the primary sedimentation tank and the secondary sedimentation tank are commonly connected to a sludge tank, the secondary sedimentation tank is connected to a clear water tank, the clear water tank is respectively connected to a first activated carbon filter and a second activated carbon filter, the bottoms of the first activated carbon filter and the second activated carbon filter are commonly connected to an RO water inlet tank, the RO water inlet tank is sequentially connected to a reverse osmosis device, an RO water production tank, multiple mixed beds and a circulating water tank, and the reverse osmosis device is also connected to the primary sedimentation tank.

[0009] As a further improvement of the present invention, a nitrogen pipeline, a hydrochloric acid pipeline and a vent pipe are respectively provided on the top of the wastewater neutralization tank, and the nitrogen pipeline leads to the bottom of the wastewater neutralization tank.

[0010] As a further improvement of the present utility model, a clean water pump and a backwash pump are respectively connected to the bottom of the clean water tank, the output end of the clean water pump is connected to the top of the first activated carbon filter and the second activated carbon filter and is provided with a valve A, and a valve B is provided on the input end of the RO water inlet tank; the output end of the backwash pump is connected to the bottom of the first activated carbon filter and the second activated carbon filter, the top of the first activated carbon filter and the second activated carbon filter is connected to the primary sedimentation tank and is provided with a valve C, and a valve D is provided on the output end of the backwash pump.

[0011] As a further improvement of the present invention, a frame filter press is provided between the sludge tank and the clean water tank.

[0012] As a further improvement of the present invention, a safety filter is connected between the RO water inlet tank and the reverse osmosis device.

[0013] As a further improvement of the present invention, a decarbonization tower is provided on the RO water production tank, and a blower is provided at the bottom of the decarbonization tower.

[0014] As a further improvement of the present invention, the bottom of the reboiler is connected to the wastewater tank through a condensed water collection pipe.

[0015] The beneficial effects of the utility model are as follows: the utility model aims at the waste alkali containing vinyl chloride generated in the production process of polyvinyl chloride, by stripping the alkali-containing wastewater, and neutralizing it with the by-product hydrochloric acid produced, and then completing the treatment through sedimentation, filter pressing, activated carbon filtration, reverse osmosis, decarbonization tower, mixed bed, etc., and then returning the treated water with qualified indicators to the circulating water pool for water replenishment and recycling, thereby realizing the recycling of waste alkali water containing vinyl chloride and the recycling of vinyl chloride, reducing production and operation costs, achieving zero discharge of wastewater, and achieving good economic and social benefits.

[0016] The switching operation of filtration and backwashing can be realized by setting the valves to work in cooperation on two activated carbon filters, in the normal operation process, by opening the valve A and the valve B, closing the valve C and the valve D, the waste water in the clean water tank is filtered through the activated carbon filter by the clean water pump; by opening the valve C and the valve D, closing the valve A and the valve B, the activated carbon filter is backwashed by using the backwashing pump, and the waste water of the activated carbon filter backwashing is transported to the primary sedimentation tank for further recovery treatment. Therefore, the impurities in the fluid can be removed, the purity of the fluid can be improved, the impurities intercepted in the filter layer can be removed, the filtering capacity of the filtering equipment can be restored, and the efficient operation of the treatment system and the safety of the water quality can be ensured. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 It is a structural schematic view of the utility model.

[0018] In the figure: 1-waste water tank; 2-waste water stripping pump; 3-waste water stripping tower; 4-chloroethylene gas cabinet; 5-waste water cooler; 6-reboiler; 7-waste water neutralization tank; 8-settling pump; 9-primary sedimentation tank; 10-secondary sedimentation tank; 11-sludge tank; 12-sludge pump; 13-frame plate filter press; 14-clean water tank; 15-clean water pump; 16-backwashing pump; 171-first activated carbon filter; 172-second activated carbon filter; 18-RO inlet tank; 19-RO inlet pump; 20-safety filter; 21-reverse osmosis device; 22-RO water tank; 23-decarbonization tower; 24-blower; 25-mixed bed inlet pump; 26-mixed bed; 27-circulating water tank; 28-vent pipe; 29-coagulant pipeline; 30-circulating water upwater pipe; 31-circulating water backwater pipe; 32-steam pipeline; 33-condensed water collecting pipeline; 34-waste lye inlet pipeline; 35-flocculating agent pipeline; 36-hydrochloric acid pipeline; 37-nitrogen pipeline; 38-concentrated water pipeline; 39-valve A; 40-valve B; 41-valve C; 42-valve D. DETAILED DESCRIPTION

[0019] The utility model will be further explained in detail in combination with the drawings and specific embodiments.

[0020] As Figure 1As shown, a high-efficiency recovery system for waste alkaline water containing vinyl chloride in the synthesis of vinyl chloride by the calcium carbide process includes a wastewater tank 1, the wastewater tank 1 is connected to a wastewater stripping tower 3, the top of the wastewater stripping tower 3 is connected to a vinyl chloride gas holder 4, the bottom of the wastewater stripping tower 3 is connected to a reboiler 6, the reboiler 6 is sequentially connected to a wastewater cooler 5, a wastewater neutralization tank 7, a primary sedimentation tank 9 and a secondary sedimentation tank 10, the bottoms of the primary sedimentation tank 9 and the secondary sedimentation tank 10 are commonly connected to a sludge tank 11, the secondary sedimentation tank 10 is connected to a clear water tank 14, the clear water tank 14 is respectively connected to a first activated carbon filter 171 and a second activated carbon filter 172, the bottoms of the first activated carbon filter 171 and the second activated carbon filter 172 are commonly connected to an RO water inlet tank 18, the RO water inlet tank 18 is sequentially connected to a reverse osmosis device 21, an RO water production tank 22, multiple mixed beds 26 and a circulating water tank 27, and the reverse osmosis device 21 is also connected to the primary sedimentation tank 9.

[0021] A nitrogen pipeline 37, a hydrochloric acid pipeline 36 and a vent pipe 28 are respectively provided at the top of the wastewater neutralization tank 7, and the nitrogen pipeline 37 leads to the bottom of the wastewater neutralization tank 7; the bottom of the clean water tank 14 is respectively connected to a clean water pump 15 and a backwash pump 16, the output end of the clean water pump 15 is connected to the top of the first activated carbon filter 171 and the second activated carbon filter 172 and is provided with a valve A39, and a valve B40 is provided on the input end of the RO water inlet tank 18; the output end of the backwash pump 16 is connected to the bottom of the first activated carbon filter 171 and the second activated carbon filter 172, the top of the first activated carbon filter 171 and the second activated carbon filter 172 is connected to the primary sedimentation tank 9 and is provided with a valve C41, and a valve D42 is provided on the output end of the backwash pump 16.

[0022] A frame filter press 13 is provided between the sludge tank 11 and the clear water tank 14; a safety filter 20 is connected between the RO water inlet tank 18 and the reverse osmosis device 21; a decarbonization tower 23 is provided on the RO water production tank 22, and a blower 24 is provided at the bottom of the decarbonization tower 23; the bottom of the reboiler 6 is connected to the wastewater tank 1 through a condensate collection pipe 33.

[0023] Example 1

[0024] Wastewater tank 1 is equipped with a steel-lined PTFE storage tank. Since the feed wastewater carries vinyl chloride, there is a safety risk. A closed storage tank is required for temporary buffer storage of the wastewater. The design needs to comprehensively consider safety, operability, environmental protection, and durability to ensure stability during storage and reduce accident risks.

[0025] A waste caustic water inlet pipe 34 is installed at the top of wastewater tank 1, with a valve control system installed on it. Wastewater tank 1 is designed to ensure the continuous operation of the wastewater stripping unit and temporarily store the waste caustic liquid from the vinyl chloride alkali washing tower. An outlet pipe is installed at the bottom of wastewater tank 1, connecting to wastewater stripping pump 2. This pipe is connected to the feed inlet of wastewater stripping tower 3, delivering wastewater to wastewater stripping tower 3. Wastewater stripping tower 3 is designed as a stainless steel sieve plate tower. Wastewater tank 1, wastewater stripping pump 2, and the inlet and outlet pipes must be made of stainless steel to prevent corrosion from the waste caustic liquid.

[0026] The bottom of the wastewater stripping tower 3 is connected to a reboiler 6. This reboiler 6 utilizes a shell-and-tube heat exchanger, with its tube-side inlet and outlet connected to the bottom of the wastewater stripping tower 3 via pipes, forming a loop. A steam pipe 32 is designed to introduce steam heating into the shell-side inlet of the reboiler 6, and a condensate collection pipe 33 is designed to discharge condensate from the shell-side. Wastewater is pumped to the upper portion of the tower by a wastewater stripping pump 2 and enters the wastewater stripping tower 3. Steam is introduced into the shell-side of the reboiler 6 for heating. The upward steam generated at the bottom of the wastewater stripping tower 3 countercurrently contacts the wastewater, providing vaporization energy. The heated vinyl chloride in the wastewater vaporizes into a gas. The vaporized vinyl chloride passes through the tower plates and contacts the wastewater, achieving sufficient gas-liquid mass transfer and vapor-phase transfer of the vinyl chloride. The vinyl chloride discharged from the top of the wastewater stripping tower 3 is piped to the vinyl chloride gas tank 4 in the main process production unit for recycling.

[0027] The design of wastewater stripper 3 requires control of parameters such as temperature, pressure, liquid level, and gas flow rate to ensure stripping efficiency, avoid overheating and overloading, and maintain continuous production. After passing through wastewater stripper 3, the vinyl chloride in the wastewater is effectively separated, enabling its recovery and utilization. Vinyl chloride gas holder 4 serves as storage equipment during the vinyl chloride purification process, regulating the supply-demand imbalance between production and consumption, storing excess gas, ensuring continuous and stable production, and avoiding production interruptions or excessive emissions.

[0028] A wastewater cooler 5 is provided at the bottom of the wastewater stripping tower 3. The wastewater cooler 5 is designed as a shell and tube heat exchanger. After the wastewater is stripped at the bottom of the wastewater stripping tower 3, the stripped wastewater is controlled by liquid level to pass through the designed height difference and enter the wastewater neutralization tank 7 from the top pipe of the wastewater neutralization tank 7. The shell side inlet of the wastewater cooler 5 is cooled by circulating water through the circulating water supply pipe 30, and the outlet is cooled through the circulating water return pipe 31. The circulating water is sent to the circulating water system of the device for recycling. The wastewater cooler 5 is designed to use circulating water to indirectly heat exchange and cool the stripped wastewater. The steam condensate from the reboiler 6 flows to the wastewater tank 1 through the condensate collecting pipe 33. Since the temperature of the steam condensate is relatively high, it flows to the wastewater tank 1 to directly heat the wastewater in advance of the steam flow, thereby reducing the heat loss of the wastewater stripping tower 3 and realizing heat recovery and utilization.

[0029] The wastewater neutralization tank 7 is designed as a stainless steel tube storage tank, specifically a steel-lined PTFE material storage tank. At the same time, the lining needs to be periodically subjected to electric spark testing to prevent corrosion and leakage. A nitrogen pipeline 37 is set at the top of the wastewater neutralization tank 7 to the bottom of the wastewater neutralization tank 7, and a hydrochloric acid pipeline 36 is designed at the top. The design concentration of hydrochloric acid addition is required to be 18%-22%. By adding hydrochloric acid to the wastewater neutralization tank 7 and turning on nitrogen stirring to ensure that the acid-base neutralization reaction is complete, the wastewater neutralization tank 7 needs to be designed with a pH value online detection and display device to facilitate timely adjustment of the amount of hydrochloric acid added. In order to avoid pressure buildup during nitrogen purging and stirring in the wastewater neutralization tank 7, a vent pipe 28 is set at the top of the wastewater neutralization tank 7 to facilitate the discharge of nitrogen during the nitrogen stirring process of the wastewater neutralization tank 7, thereby controlling the pH value of the waste alkali solution in the wastewater neutralization tank 7 to be stable between 7-9.

[0030] An outlet is provided at the bottom of the wastewater neutralization tank 7 and is connected to a sedimentation pump 8 through a pipeline. The outlet of the sedimentation pump 8 transports the neutralized wastewater in the wastewater neutralization tank 7 to the primary sedimentation tank 9 through a pipeline. The wastewater enters the bottom of the sedimentation tank from one side of the primary sedimentation tank 9 and flows to the subsequent treatment process through the overflow port at the top of the other side. A coagulant is quantitatively added to the top of the primary sedimentation tank 9 through a coagulant pipeline 29. Through charge neutralization, compression of the double layer, etc., the stability of the suspended particles is destroyed, the repulsion between the particles is weakened, and preparations are made for the subsequent flocculation process. Most flocculants are mainly polyaluminum chloride. After being added to the water, multivalent cations are released to neutralize the charge of the negatively charged suspended particles in the water, thereby reducing the electrostatic repulsion between the particles and facilitating the aggregation and sedimentation of the suspended matter, thereby causing the chloride salt suspended matter contained in the wastewater to settle at the bottom of the sedimentation tank and flow to the sludge tank 11 through a pipeline. The supernatant of the wastewater overflows from the other side of the top of the primary sedimentation tank 9 to the secondary sedimentation tank 10. During the design process, the primary sedimentation tank 9, the secondary sedimentation tank 10, the sludge tank 11 and the clear water tank 14 are set with high head differences in sequence. The supernatant of the wastewater can realize gravity sedimentation flow through the high head difference, and flow to the clear water tank 14 after passing through the primary sedimentation tank 9 and the secondary sedimentation tank 10 in sequence.

[0031] The primary sedimentation tank 9 and the secondary sedimentation tank 10 use gravity sedimentation to allow microorganisms to degrade organic matter, remove BOD, ammonia nitrogen and phosphorus, biodegrade, degrade pollution, and improve water quality. At the same time, suspended matter in the wastewater (chloride salts, sediment, soil, biosolids, suspended organic matter) is settled to the bottom, and the supernatant overflows to remove suspended matter.

[0032] The structural principles of the secondary sedimentation tank 10 are the same as those of the primary sedimentation tank 9. A flocculant pipe 35 is provided at the top of the secondary sedimentation tank 10 to quantitatively add flocculants, further promoting and optimizing the growth and aggregation of the initially formed flocs, making them more stable, larger, and easier to settle. Polyacrylamide is typically used as the flocculant. The settled suspended solids are discharged to the sludge tank 11 through a bottom pipe, and the supernatant overflows from the other side of the top of the secondary sedimentation tank 10 to the clear water tank 14. The design volumes of the primary and secondary sedimentation tanks 9 and 10 must meet sedimentation requirements, and the dosage of coagulants and flocculants must be calculated based on production needs.

[0033] The bottom of the sludge pool 11 is connected to the sludge pump 12 through the sludge pump 12, which transports the sludge to the frame filter press 13 for filtration. After filtration, the sludge passes through the collection tank and is dried and collected for treatment as mercury-containing sludge. The clear liquid from the frame filter press 13 is transported to the clear water pool 14 for the next step of treatment.

[0034] An outlet pipe is provided at the bottom of the clean water tank 14, connected to a clean water pump 15 and a backwash pump 16 via a tee. A pipe is provided at the outlet of the clean water pump 15 to transport wastewater from the clean water tank 14 to two activated carbon filters for filtration. After filtering through the first activated carbon filter 171 and the second activated carbon filter 172, the wastewater enters the RO inlet tank 18 for temporary storage. Two activated carbon filters are installed in parallel and filled with activated carbon. Passing through the activated carbon filters, the wastewater effectively absorbs residual chlorides, such as sodium chloride, in the water, protecting the subsequent reverse osmosis unit 21, extending equipment life, and reducing disinfection byproducts.

[0035] The first activated carbon filter 171 and the second activated carbon filter 172 can be switched between filtering and backwashing by means of valves. During normal operation, valves A39 and B40 are opened, valves C41 and D42 are closed, and the clean water pump 15 filters the wastewater in the clean water tank 14 through the activated carbon filter. Since the waste alkaline water containing vinyl chloride is transported intermittently, the activated carbon filter can be backwashed when the upstream system stops transporting it. This is done by opening valves C41 and D42, closing valves A39 and B40, and using the backwash pump 16. The backwash wastewater from the activated carbon filter is then piped to the primary sedimentation tank 9 for further recovery and treatment. The activated carbon filter can be operated intermittently during production, or backwashing can be performed using a reference pressure differential between the inlet and outlet pressure gauges.

[0036] Wastewater filtered through first and second activated carbon filters 171, 172 enters RO inlet tank 18. RO inlet tank 18 is constructed of stainless steel, and its capacity and other design parameters must match the capacity of the subsequent reverse osmosis unit 21. An outlet is located at the bottom of RO inlet tank 18, connected by a pipe to RO inlet pump 19. In turn, RO inlet pump 19 is connected by a pipe to safety filter 20. Safety filter 20 primarily removes fine particles (0.1-5 microns), protects the RO membrane from scratches, extends its lifespan, removes microparticles and colloids from the water, improves inlet water clarity, ensures efficient RO penetration, reduces membrane contamination, and improves water production and effluent quality.

[0037] The outlet pipe of the security filter 20 is connected to the water inlet of the reverse osmosis unit 21. The reverse osmosis unit 21 primarily utilizes a semipermeable membrane with selective permeability, allowing water molecules to pass through while blocking large molecules, ions, organic matter, bacteria, viruses, and the like, effectively separating water from impurities. After wastewater from the security filter 20 outlet is treated by the reverse osmosis unit 21, the concentrate outlet of the reverse osmosis unit 21 is transported via concentrate pipe 38 to the primary sedimentation tank 9 for further recycling. The water produced by the reverse osmosis unit 21 is piped to the RO water production tank 22. A decarbonization tower 23 is located atop the RO water production tank 22, and a blower 24 is installed at the bottom of the decarbonization tower 23. The water produced by the reverse osmosis unit 21 is sprayed through the top of the decarbonization tower 23 and flows into the RO water production tank 22. During operation, the blower 24 provides reverse air to the decarbonization tower 23, removing carbon dioxide from the RO water and reducing the production load of the subsequent mixed bed 26. The purpose of the decarbonization tower 23 is to reduce the pH value of the incoming water by reacting with carbon dioxide to form carbonic acid, which affects the resin exchange capacity and reduces efficiency.

[0038] An outlet is set at the bottom of the RO water tank 22, which is connected to the mixed bed water inlet pump 25 through a pipeline. The RO water is pumped to the two mixed beds 26 for treatment. The mixed bed 26 needs to be designed with an acid-base regeneration device. Anionic and cation resins are added inside the mixed bed 26. The cation resin attracts and removes cations (such as sodium, calcium, and magnesium), and the anion resin absorbs anions (such as chloride and sulfate). When water passes through the mixed bed 26, the cation and anion resins are mixed and interspersed with each other, and the reactions proceed almost simultaneously, removing ions in the water through rapid exchange. At the same time, H + OH - Immediately combined, little counter-ion formation occurs, reducing the impact of counter-ions, ensuring thorough exchange and good treated water quality. Ion exchange is carried out through the anionic and cation-ion resins in the mixed bed 26, further removing influent ions such as calcium and magnesium from the RO product water, ensuring that the treated wastewater conductivity is ≤10US / CM. After passing through the mixed bed 26, the wastewater is tested and sent to the circulating water pool 27 for replenishment and reuse.

[0039] By using the above-mentioned device, efficient recovery of waste alkaline water containing vinyl chloride in the synthesis of vinyl chloride by the calcium carbide method can be achieved, vinyl chloride can be recycled and utilized, and zero discharge of waste water can be achieved. The device used in the utility model is a device for recovering flammable and explosive media. The design and installation must comply with chemical fire and explosion protection requirements, and nitrogen must be used for replacement before the device is put into operation.

Claims

1. A highly efficient recovery system for waste alkaline water containing vinyl chloride in the synthesis of vinyl chloride by the calcium carbide process, characterized by: The invention comprises a wastewater tank (1), wherein the wastewater tank (1) is connected to a wastewater stripping tower (3), the top of the wastewater stripping tower (3) is connected to a vinyl chloride gas holder (4), the bottom of the wastewater stripping tower (3) is connected to a reboiler (6), the reboiler (6) is connected in sequence to a wastewater cooler (5), a wastewater neutralization tank (7), a primary sedimentation tank (9) and a secondary sedimentation tank (10), the bottoms of the primary sedimentation tank (9) and the secondary sedimentation tank (10) are commonly connected to a sludge tank (11), and the secondary sedimentation tank (10) is connected to a clean water tank. The clean water tank (14) is connected to a first activated carbon filter (171) and a second activated carbon filter (172), respectively. The bottoms of the first activated carbon filter (171) and the second activated carbon filter (172) are connected to a RO water inlet tank (18). The RO water inlet tank (18) is connected in sequence to a reverse osmosis device (21), an RO water production tank (22), a plurality of mixed beds (26) and a circulating water tank (27). The reverse osmosis device (21) is also connected to a primary sedimentation tank (9).

2. The efficient recovery system for waste alkaline water containing vinyl chloride in the synthesis of vinyl chloride by the calcium carbide process according to claim 1, characterized in that: A nitrogen pipeline (37), a hydrochloric acid pipeline (36) and a vent pipe (28) are respectively provided on the top of the wastewater neutralization tank (7), and the nitrogen pipeline (37) leads to the bottom of the wastewater neutralization tank (7).

3. The efficient recovery system for waste alkaline water containing vinyl chloride in the synthesis of vinyl chloride by the calcium carbide process according to claim 1 or 2, characterized in that: The bottom of the clean water tank (14) is connected to a clean water pump (15) and a backwash pump (16), respectively. The output end of the clean water pump (15) is connected to the top of the first activated carbon filter (171) and the second activated carbon filter (172) and is provided with a valve A (39). The input end of the RO water inlet tank (18) is provided with a valve B (40). The output end of the backwash pump (16) is connected to the bottom of the first activated carbon filter (171) and the second activated carbon filter (172). The top of the first activated carbon filter (171) and the second activated carbon filter (172) are connected to the primary sedimentation tank (9) and are provided with a valve C (41). The output end of the backwash pump (16) is provided with a valve D (42).

4. The efficient recovery system for waste alkaline water containing vinyl chloride in the synthesis of vinyl chloride by the calcium carbide process according to claim 3, characterized in that: A frame filter press (13) is provided between the sludge tank (11) and the clean water tank (14).

5. The high-efficiency recovery system for waste alkaline water containing vinyl chloride in the synthesis of vinyl chloride by the calcium carbide process according to claim 4, characterized in that: A safety filter (20) is connected between the RO water inlet tank (18) and the reverse osmosis device (21).

6. The high-efficiency recovery system for waste alkaline water containing vinyl chloride in the synthesis of vinyl chloride by the calcium carbide process according to claim 5, characterized in that: A decarbonization tower (23) is provided on the RO water production tank (22), and a blower (24) is provided at the bottom of the decarbonization tower (23).

7. The high-efficiency recovery system for waste alkaline water containing vinyl chloride in the synthesis of vinyl chloride by the calcium carbide process according to claim 1, characterized in that: The bottom of the reboiler (6) is connected to the wastewater tank (1) via a condensed water collection pipe (33).

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