Diketene rectification method and device

Abstract

The invention relates to a diketene rectification method and device. A polymerization inhibitor is added to a pipeline through which the crude ketene enters the ketene dimer rectifying tower, and the crude ketene dimer and the polymerization inhibitor are mixed and then enter the ketene dimer rectifying tower together; after the tower top gas is condensed, one part is refluxed, the other part is extracted, and the product purity is adjusted to be greater than 99.6 wt% by utilizing the reflux ratio; one part of kettle liquid in the tower kettle of the diketene rectifying tower enters a reboiler to evaporate and concentrate residues, the vaporized kettle liquid returns to the tower and is subjected to vapor-liquid separation in the tower, a liquid phase returns to the tower kettle, and a gas phase rises to the tower top; the other part of kettle liquid in the kettle of the ketene dimer rectifying tower is continuously discharged into a residue storage tank, and the residue storage tank controls the temperature of residues in an external circulation cooling mode. The equipment comprises a diketene rectifying tower, a reboiler, a static mixer, a vacuum pump, a condenser, a reflux tank and the like. According to the method, polymerization of diketene is prevented by adding the polymerization inhibitor, and diketene is separated and refined by using the efficient filler, so that the method has the advantages of good product quality and high recovery rate.

Description

Technical Field

[0001] The invention relates to a diketene distillation system, and in particular to a diketene distillation method and device with good product quality, high recovery rate, continuous stability, safety and environmental protection. Background Art

[0002] Diketene, also known as acetyl ketene and diketene, is a colorless or light yellow flammable liquid with a pungent odor. It is mainly used as a raw material for organic synthesis, such as the synthesis of ketobutyric acid, acetoacetic acid esters, amides and pyrazolones. It is also used to make plasticizers, dyes, synthetic fibers, cellulose ester films, as well as medicines (antipyretics and tranquilizers), pesticides, food preservatives, spices, foods (sweeteners), feed additives (quinoline dextrose), synthetic resins, rubbers, additives, etc.

[0003] Acetic acid cracking is the main method for producing diketene. Its main process is as follows: after acetic acid evaporates, it enters the heating furnace under vacuum conditions, is heated to 700-780°C, and is cracked under the action of catalysts such as triethyl phosphate and diamine hydrogen phosphate to produce ketene and water. At the same time, side reactions occur to produce methane, carbon dioxide, ethylene, coke, etc. The cracked gas is sent to the absorption tower, where it is absorbed by the absorbent diketene. Subsequently, it is polymerized in the bottom of the tower to produce diketene. The tail gas of the absorption tower is absorbed by water and sent to the incineration system. Part of the generated crude diketene is sent to the top of the tower as an absorbent, and part is sent to the diketene distillation system. Refined diketene is obtained at the top of the distillation tower, and the residue discharged from the bottom of the tower is sent to the hydrolysis recovery section.

[0004] "Diketene" published by Shanghai Pengpu Chemical Plant in 1977 introduced a production process of diketene: acetic acid is cracked under vacuum and high temperature under the catalysis of triester phosphate to generate diketene, and diketene is cooled, absorbed and polymerized to generate crude diketene, which is then distilled under reduced pressure in a membrane evaporator to obtain diketene product. This method uses a membrane evaporator to purify diketene, but has problems such as small equipment capacity, difficulty in large-scale expansion, the need to store residues in a cart, the inability to operate continuously during the refining process, and low diketene yield and purity.

[0005] CN112479847A reports a method for preparing diketene by acetic acid cracking. In the diketene refining section, a film evaporator is used for distillation, a packed tower is used for decolorization, and the residue intermediate tank is further distilled to recover diketene. The maximum feed rate of the film evaporator reported is 550kg / h, the production scale is small, and it is difficult to expand the production capacity. It adopts two distillations, the process is complicated, and the residue intermediate tank is an intermittent distillation operation, which has the potential safety hazards of over-temperature and over-pressure. In addition, the packing tower has insufficient reflux, and a high-purity diketene product cannot be produced.

[0006] CN106749112A reports a continuous diketene distillation process. Diketene gas continuously enters a film evaporator, and after evaporation, it undergoes a primary condensation to obtain a diketene product. The secondary condensate and evaporation residue are esterified with methanol to serve as a cracking furnace fuel. The reported diketene purity is 99%, and the impurity content is relatively high. The feed rate of the film evaporator is 200kg / h, and the equipment capacity is small, making it difficult to scale up.

[0007] In view of the current problems of diketene distillation system, such as small production capacity, low yield, poor product quality, long residue stagnation time and safety hazards, a diketene distillation system capable of continuous and large-scale production has been designed and invented, which can effectively avoid the above problems and is crucial to improving the safety of the diketene process and the quality and yield of diketene products. Summary of the invention

[0008] In view of the shortcomings of the prior art, the present invention proposes a diketene distillation method and device. The method fully considers the material properties and equipment characteristics, reasonably designs the process route and refining device, and ensures the continuous stability of the operation and the inherent safety of the system under the premise of obtaining high-quality products.

[0009] In order to achieve the above object, the technical solution of the present invention is as follows:

[0010] A diketene distillation method comprises the following steps:

[0011] (1) adding a polymerization inhibitor to the pipeline of the crude diketene entering the diketene distillation tower, and the crude diketene and the polymerization inhibitor are mixed and enter the diketene distillation tower together; after the top gas is condensed, part of it is refluxed and part of it is extracted, and the reflux ratio is used to adjust the product purity to >99.6wt%;

[0012] (2) A portion of the diketene distillation tower bottom liquid enters the reboiler to evaporate and concentrate the residue, and the vaporized bottom liquid returns to the tower, where vapor-liquid separation is performed, the liquid phase returns to the tower bottom, and the gas phase rises to the top of the tower;

[0013] (3) Another part of the diketene distillation tower kettle liquid is continuously discharged into the residue storage tank, and the residue storage tank adopts external circulation cooling to control the residue temperature.

[0014] The polymerization inhibitor is one or more of methanol, ethanol, ethylene glycol, n-butanol and isopropanol, and the amount of the polymerization inhibitor added is 0.1‰ to 10‰ of the crude diketene feed amount.

[0015] The diketene distillation tower is a packed tower with 10 to 40 theoretical plates, wherein the distillation section has 5 to 30 theoretical plates.

[0016] The diketene distillation tower has a top pressure of 6-15 kPaA, a top temperature of 45-60°C, a bottom temperature of 60-75°C, and a reflux ratio of 0.2-5.

[0017] The gas phase at the top of the diketene distillation tower is condensed to 0-10° C. and then enters the reflux tank.

[0018] The discharge amount of the diketene distillation tower bottom residue is 5-20wt% of the crude diketene feed amount.

[0019] The residue storage tank adopts an external circulation cooling method to control the temperature of the material in the tank. The temperature of the material in the tank is 0-10°C, and the ratio of the circulation amount to the feed amount is 5-30.

[0020] The reboiler is operated in a flow boiling vaporization and evaporation mode.

[0021] The diketene distillation tower has two feeding modes, namely, feeding into the middle of the tower and feeding into the bottom of the tower.

[0022] The equipment of the present invention comprises a diketene distillation tower, a reboiler, a static mixer, a vacuum pump, a condenser, a reflux tank, etc. The method prevents diketene polymerization by adding a polymerization inhibitor and separates and purifies diketene by using a high-efficiency filler, and has the advantages of good product quality and high recovery rate.

[0023] The present invention provides a device for a diketene distillation method, comprising a polymerization inhibitor storage tank 1, a polymerization inhibitor delivery pump 2, a static mixer 3, a diketene distillation tower 4, a reboiler 5, a condenser 6, a reflux tank 7, a reflux pump 8, a residue delivery pump 9, a residue storage tank 10, a cooling circulation pump 11, a circulating cooler 12, a hydrolysis feed pump 13, and a vacuum pump 14; the discharge of the polymerization inhibitor storage tank 1 is connected to the feed of the polymerization inhibitor delivery pump 2; the discharge of the polymerization inhibitor delivery pump 2 is connected to the feed of the static mixer 3 after merging with the crude diketene feed; the discharge of the static mixer 3 is divided into two paths and connected to the feed of the diketene distillation tower 4, and the feed ports of the diketene distillation tower 4 are respectively in the tower and in the bottom of the tower; the discharge from the top of the diketene distillation tower 4 is connected to the feed of the condenser 6, the lower liquid of the condenser 6 is connected to the feed of the reflux tank 7, and the tail gas of the condenser 6 is connected to the feed of the vacuum pump 14. The tail gas of vacuum pump 14 is incinerated; the discharge of reflux tank 7 is connected to the feed of reflux pump 8, and the discharge of reflux pump 8 is divided into two streams, one of which is connected to diketene distillation tower 4, and the other is extracted as product; the discharge of diketene distillation tower 4 kettle is divided into two streams, one of which is connected to the inlet of reboiler 5, and the other is connected to the feed of residue delivery pump 9, and the outlet of reboiler 5 is connected to diketene distillation tower 4; the discharge of residue delivery pump 9 is divided into two streams, one of which is connected to diketene distillation tower 4, and the other is connected to the feed of residue storage tank 10; the discharge of residue storage tank 10 is divided into two streams, one of which is connected to the inlet of cooling circulation pump 11, and the other is connected to the feed of hydrolysis feed pump 13; the outlet of cooling circulation pump 11 is connected to the inlet of circulation cooler 12, and the outlet of circulation cooler 12 is connected to residue storage tank 10; the discharge of hydrolysis feed pump 13 goes to hydrolysis section.

[0024] The specific instructions are as follows:

[0025] In the technical scheme, the polymerization inhibitor is one or more selected from methanol, ethanol, ethylene glycol, n-butanol and isopropanol, and the amount of the polymerization inhibitor added is 0.1‰ to 10‰ of the crude diketene feed amount; the diketene distillation tower has two feeding methods, namely, feeding in the middle of the tower and feeding in the tower bottom; the diketene distillation tower is a packed tower, with a total of 10 to 40 theoretical plates, of which the distillation section has 5 to 30 theoretical plates; the tower bottom uses a reboiler to concentrate the residue; the tower top pressure of the diketene distillation tower is 6 to 15 kPaA, the tower top temperature is 45 to 60°C, the tower bottom temperature is 60 to 75°C, and the reflux ratio is 0.2 to 5; the tower top gas phase is condensed to 0 to 10°C and then enters a reflux tank; the tower bottom residue discharge amount is 5 to 20wt% of the crude diketene feed amount; the residue storage tank uses an external circulation cooling method to control the material temperature in the tank, the material temperature in the tank is 0 to 10°C, and the ratio of the circulation amount to the feed amount is 5 to 30. Based on the above scheme, the purity of the refined diketene product produced by the present invention is ≥99.6wt% and the yield is ≥94%.

[0026] The polymerization inhibitor enters the polymerization inhibitor delivery pump 2 from the polymerization inhibitor storage tank 1, and the crude diketene from the polymerization section is mixed in the static mixer 3, and then enters the diketene distillation tower 4. The polymerization inhibitor is one of methanol, ethanol, ethylene glycol, n-butanol, and isopropanol: such as ethylene glycol, isopropanol or a combination of several alcohols, preferably a mixed alcohol containing ethylene glycol, ethylene glycol accounts for 50-100wt%, and the preferred feeding method is to add the material in the tower.

[0027] The material from the static mixer 3 enters the diketene distillation tower 4, which is a packed tower. The gas phase at the top of the tower goes to the condenser 6 for condensation, and then enters the reflux tank 7 after condensation. The liquid phase of the reflux tank 7 enters the reflux pump 8, part of which is extracted as a product and part of which is refluxed to the top of the tower. The uncondensed tail gas at the top of the tower enters the vacuum pump 14 and is sent to the incineration unit for treatment. The preferred reflux ratio is 0.5-2;

[0028] A part of the liquid phase in the bottom of the diketene distillation tower 4 is sent to the reboiler 5, where it is partially evaporated into gas-liquid two-phase and returned to the diketene distillation tower 4; another part of the liquid phase in the bottom of the tower enters the residue delivery pump 9 and is sent to the residue storage tank 10. The preferred discharge amount of the bottom residue is 8-12wt% of the crude diketene feed amount;

[0029] The residue from the residue delivery pump 9 enters the residue storage tank 10, and a part of the discharge from the residue storage tank 10 enters the cooling circulation pump 11, then enters the circulation cooler 12, and returns to the residue storage tank 10; another part of the discharge from the residue storage tank 10 enters the hydrolysis feed pump 13 and is sent to the hydrolysis unit for treatment. The preferred ratio of the circulation amount to the feed amount is 10 to 20.

[0030] The beneficial effects of the present invention are as follows:

[0031] Acetic acid is cracked under vacuum and high temperature conditions to generate ketene gas, which is then absorbed and polymerized to generate crude diketene in the liquid phase, which is then purified by distillation to obtain the diketene product, and the residue is recovered in the hydrolysis section. The distillation process is crucial to improving the quality of diketene products and reducing material consumption. The traditional diketene distillation process uses a membrane evaporator to evaporate and purify diketene, which has the disadvantages of small production capacity, low diketene purity, and high safety risks.

[0032] The purity of the refined diketene product produced by the present invention is ≥99.6wt%, and the yield is ≥94%, which is much better than the existing indicators: purity 98.5%w, yield 90%; the distillation capacity expansion is less restricted by equipment and is easy to expand. In a certain embodiment, the processing capacity of refined diketene is 1.4 tons / h, which greatly improves the processing capacity compared with the existing film evaporator feed of 200-550kg / h, and there is no bottleneck in the processing capacity expansion of the distillation device; the process energy consumption is low, and the material unit consumption is 0.2-0.5 tons of steam / ton of diketene, and the steam consumption can be adjusted according to the product quality requirements. The tower bottom residue has good fluidity, and the slag discharge amount is 5-20wt% of the crude diketene feed amount. The process is continuous and stable, there is no risk of liquid accumulation polymerization overtemperature and overpressure, and the production process is inherently safe. The tower bottom material has a small temperature rise, a fast flow rate, and is not easy to be blocked, and the operation is stable. The device has a high degree of automation, a small number of operating points, and can realize DCS automatic control without manual intervention. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 :A diketene distillation system of the present invention

[0034] As shown in the figure: inhibitor storage tank 1, inhibitor delivery pump 2, static mixer 3, diketene distillation tower 4, reboiler 5, condenser 6, reflux tank 7, reflux pump 8, residue delivery pump 9, residue storage tank 10, cooling circulation pump 11, circulation cooler 12, hydrolysis feed pump 13, vacuum pump 14. DETAILED DESCRIPTION

[0035] The specific implementation mode of the present invention is combined with Figure 1 Further description, but the scope of the description of the present invention is not limited to this. The inhibitor from the inhibitor storage tank 1 is sent to the main pipeline by the inhibitor delivery pump 2, and merges with the crude diketene from the upstream absorption tower kettle. After merging, it enters the static mixer 3, and after being fully mixed, it enters the diketene distillation tower 4. The top gas phase enters the reflux tank 7 after condensation by the condenser 6, and the reflux tank 7 discharges to the reflux pump 8. Part of the discharge is extracted as a product, and part is refluxed to the top of the tower. The uncondensed tail gas at the top of the tower enters the vacuum pump 14 and is sent to the incineration unit for treatment. The tower kettle adopts a reboiler 5 to concentrate the residue, and the residue is continuously delivered by the residue delivery pump 9 after concentration. The residue enters the residue storage tank 10 for storage, and one discharge of the residue storage tank 10 goes to the cooling circulation pump 11, and then goes to the circulation cooler 12, and returns to the residue storage tank 10 after cooling; another discharge of the residue storage tank 10 goes to the hydrolysis feed pump 13 and is sent to the hydrolysis unit for treatment.

[0036] Embodiment 1:

[0037] In this embodiment, the amount of crude diketene from the synthesis section is 1400 kg / h, which is fed to the diketene rectification column 4 through an upstream feed pump, wherein the diketene content in the feed is 96.8 wt %, and the acetic anhydride content is 3.0 wt %. The inhibitor is fed from the inhibitor storage tank 1 to the crude diketene feed pipeline through an inhibitor delivery pump 2, wherein the inhibitor is a mixture of methanol and ethylene glycol, with a mass ratio of 1:1, and the addition amount is 14 kg / h.

[0038] The combined feed is mixed in the static mixer 3 and then sent to the diketene distillation tower 4 for distillation separation. The feed position of the diketene distillation tower 4 is in the tower. The diketene distillation tower is a packed tower with a total of 10 theoretical plates, of which the distillation section has 5 theoretical plates. The heavy component flows to the tower bottom, is heated and evaporated into a gas-liquid two-phase mixture in the reboiler 5, and then returns to the diketene distillation tower 4 for gas-liquid separation in the tower. The light component gas rises to the top of the tower, and the heavy component residue returns to the tower bottom. The steam addition amount of the reboiler 5 is 550kg / h, the tower bottom temperature is 60℃, and the tower bottom pressure is 10.3kPaA.

[0039] The gas phase at the top of the tower is condensed by the condenser 6 and sent to the reflux tank 7. The condensate is sent to the reflux pump 8. A part of it is extracted, and the extraction amount is 1330 kg / h. The rest is refluxed to the diketene distillation tower 4. The top temperature of the diketene distillation tower is 45.0°C, the top pressure is 6 kPaA, and the condensate temperature is 8.1°C. The tail gas at the top of the tower is sent to the vacuum pump 14, and the inlet pressure of the vacuum pump 14 is 5.1 kPaA.

[0040] The bottom residue of the tower is continuously discharged to the residue storage tank 10 by the residue delivery pump 9, the discharge rate is 70kg / h, and the temperature of the residue storage tank 10 is 10.0°C. A part of the discharge from the residue storage tank 10 is circulated back to the residue storage tank 10 via the cooling circulation pump 11 and the circulation cooler 12, and the other part is sent to the hydrolysis section by the hydrolysis feed pump 13, and the ratio of the circulation rate to the feed rate is 5. In this embodiment, the content of diketene in the product is 99.8wt%, and the distillation yield is 95.9%.

[0041] Embodiment 2:

[0042] In this embodiment, the crude diketene amount from the synthesis section is 1400 kg / h, which is pumped to the diketene rectification column 4 through the upstream feed pump, and the diketene content in the feed is 84.7 wt%, and the acetic anhydride content is 8.5 wt%. The inhibitor is sent from the inhibitor storage tank 1 to the crude diketene feed pipeline through the inhibitor delivery pump 2, and the inhibitor is a mixture of n-butanol and ethylene glycol, with a mass ratio of 1:1, and the addition amount is 1.2 kg / h.

[0043] The combined feed is mixed in the static mixer 3 and then sent to the diketene distillation tower 4 for distillation separation. The feed position of the diketene distillation tower 4 is the tower bottom. The diketene distillation tower is a packed tower with a total of 20 theoretical plates, of which the distillation section has 10 theoretical plates. The heavy component flows to the tower bottom, is heated and evaporated into a gas-liquid two-phase mixture in the reboiler 5, and then returns to the diketene distillation tower 4 for gas-liquid separation in the tower. The light component gas rises to the top of the tower, and the heavy component residue returns to the tower bottom. The steam addition amount of the reboiler 5 is 800kg / h, the tower bottom temperature is 66.8℃, and the tower bottom pressure is 11.5kPaA.

[0044] The gas phase at the top of the tower is condensed by the condenser 6 and sent to the reflux tank 7. The condensate is sent to the reflux pump 8. A part of it is produced, and the production amount is 1120 kg / h. The rest is refluxed to the diketene distillation tower 4. The top temperature of the diketene distillation tower is 56.1°C, the top pressure is 9.5 kPaA, and the condensate temperature is 0°C. The tail gas at the top of the tower is sent to the vacuum pump 14, and the inlet pressure of the vacuum pump 14 is 7.5 kPaA.

[0045] The bottom residue of the tower is continuously discharged to the residue storage tank 10 by the residue delivery pump 9, the discharge rate is 280kg / h, and the temperature of the residue storage tank 10 is 8.0°C. A part of the discharge from the residue storage tank 10 is circulated back to the residue storage tank 10 via the cooling circulation pump 11 and the circulation cooler 12, and the other part is sent to the hydrolysis section by the hydrolysis feed pump 13, and the ratio of the circulation rate to the feed rate is 30. In this embodiment, the content of diketene in the product is 99.7wt%, and the distillation yield is 94.0%.

[0046] Embodiment 3:

[0047] In this embodiment, the crude diketene amount from the synthesis section is 1000 kg / h, which is fed to the diketene rectification column 4 through an upstream feed pump, wherein the diketene content in the feed is 93.3 wt % and the acetic anhydride content is 5.5 wt %. The inhibitor is fed from the inhibitor storage tank 1 to the crude diketene feed pipeline through an inhibitor delivery pump 2, wherein the inhibitor is ethylene glycol, and the addition amount is 0.1 kg / h.

[0048] The combined feed is mixed in the static mixer 3 and then sent to the diketene distillation tower 4 for distillation separation. The feed position of the diketene distillation tower 4 is in the tower. The diketene distillation tower is a packed tower with a total of 40 theoretical plates, of which the distillation section has 25 theoretical plates. The heavy component flows to the tower bottom, is heated and evaporated into a gas-liquid two-phase mixture in the reboiler 5, and then returns to the diketene distillation tower 4 for gas-liquid separation in the tower. The light component gas rises to the top of the tower, and the heavy component residue returns to the tower bottom. The steam addition amount of the reboiler 5 is 400kg / h, the tower bottom temperature is 70.5℃, and the tower bottom pressure is 15.5kPaA.

[0049] The gas phase at the top of the tower is condensed by the condenser 6 and sent to the reflux tank 7. The condensate is sent to the reflux pump 8. A part of it is produced at a production rate of 900 kg / h, and the rest is refluxed to the diketene distillation tower 4. The top temperature of the diketene distillation tower is 60.0°C, the top pressure is 15.0 kPaA, and the condensate temperature is 10.0°C. The tail gas at the top of the tower is sent to the vacuum pump 14, and the inlet pressure of the vacuum pump 14 is 13.8 kPaA.

[0050] The bottom residue of the tower is continuously discharged to the residue storage tank 10 by the residue delivery pump 9, the discharge rate is 100kg / h, and the temperature of the residue storage tank 10 is 0°C. A part of the discharge from the residue storage tank 10 is circulated back to the residue storage tank 10 via the cooling circulation pump 11 and the circulation cooler 12, and the other part is sent to the hydrolysis section by the hydrolysis feed pump 13, and the ratio of the circulation rate to the feed rate is 30. In this embodiment, the content of diketene in the product is 99.9wt%, and the distillation yield is 96.4%.

[0051] The above describes the embodiments of the present invention in conjunction with the accompanying drawings. The present invention is not limited to the above experiments, and various changes can be made according to the purpose of the invention. Any modifications, combinations, simplifications, equivalent replacements, etc. made according to the implementation spirit and principles of the technical solution of the present invention should be equivalent replacement modes. As long as they meet the purpose of the invention and do not deviate from the technical principles and inventive concepts of the present invention, they should be included in the protection scope of the present invention.

Claims

1. A diketene distillation method, characterized in that: The steps include: (1) adding a polymerization inhibitor to the pipeline of the crude diketene entering the diketene distillation tower, and the crude diketene and the polymerization inhibitor are mixed and enter the diketene distillation tower together; after the top gas is condensed, part of it is refluxed and part of it is extracted, and the reflux ratio is used to adjust the product purity to >99.6wt%; (2) A portion of the diketene distillation tower bottom liquid enters the reboiler to evaporate and concentrate the residue, and the vaporized bottom liquid returns to the tower, where vapor-liquid separation is performed, the liquid phase returns to the tower bottom, and the gas phase rises to the top of the tower; (3) Another part of the diketene distillation tower kettle liquid is continuously discharged into the residue storage tank, and the residue storage tank adopts external circulation cooling to control the residue temperature.

2. The diketene distillation method according to claim 1, characterized in that: The polymerization inhibitor is one or more of methanol, ethanol, ethylene glycol, n-butanol and isopropanol, and the amount of the polymerization inhibitor added is 0.1‰ to 10‰ of the crude diketene feed amount.

3. The diketene distillation method according to claim 1, characterized in that: The diketene distillation tower is a packed tower with 10 to 40 theoretical plates, of which the distillation section has 5 to 30 theoretical plates.

4. The diketene distillation method according to claim 1, characterized in that: The top pressure of the diketene distillation tower is 6-15 kPaA, the top temperature is 45-60°C, the bottom temperature is 60-75°C, and the reflux ratio is 0.2-5.

5. The diketene distillation method according to claim 1, characterized in that: The gas phase at the top of the diketene distillation tower is condensed to 0-10°C and then enters the reflux tank.

6. The diketene distillation method according to claim 1, characterized in that: The discharge amount of the diketene distillation tower bottom residue is 5 to 20 wt % of the crude diketene feed amount.

7. The diketene distillation method according to claim 1, characterized in that: The residue storage tank adopts external circulation cooling to control the temperature of the material in the tank. The temperature of the material in the tank is 0-10°C, and the ratio of the circulation amount to the feed amount is 5-30.

8. The diketene distillation method according to claim 1, characterized in that: The reboiler operates in a flow boiling vaporization mode.

9. The diketene distillation method according to claim 1, characterized in that: There are two feeding methods for the diketene distillation tower, namely, feeding into the middle of the tower and feeding into the bottom of the tower.

10. An apparatus for implementing the diketene distillation method according to claim 1, characterized in that: It includes an inhibitor storage tank 1, an inhibitor delivery pump 2, a static mixer 3, a diketene distillation tower 4, a reboiler 5, a condenser 6, a reflux tank 7, a reflux pump 8, a residue delivery pump 9, a residue storage tank 10, a cooling circulation pump 11, a circulating cooler 12, a hydrolysis feed pump 13, and a vacuum pump 14; the discharge of the inhibitor storage tank 1 is connected to the feed of the inhibitor delivery pump 2; the discharge of the inhibitor delivery pump 2 is combined with the crude diketene feed and then connected to the feed of the static mixer 3; the discharge of the static mixer 3 is divided into two routes and connected to the feed of the diketene distillation tower 4, and the feed ports of the ketene distillation tower 4 are respectively in the tower and in the tower reactor; The top discharge of diketene distillation tower 4 is connected to the feed of condenser 6, the lower liquid of condenser 6 is connected to the feed of reflux tank 7, the tail gas of condenser 6 is connected to the inlet of vacuum pump 14, and the tail gas of vacuum pump 14 is incinerated; the discharge of reflux tank 7 is connected to the feed of reflux pump 8, and the discharge of reflux pump 8 is divided into two streams, one of which is connected to diketene distillation tower 4 and the other is extracted as product; the discharge of diketene distillation tower 4 is divided into two streams, one of which is connected to the inlet of reboiler 5 and the other is connected to the feed of residue delivery pump 9, and the outlet of reboiler 5 is connected to diketene distillation tower 4; The discharge of the residue delivery pump 9 is divided into two streams, one of which is connected to the diketene distillation tower 4, and the other is connected to the residue storage tank 10 feed; the discharge of the residue storage tank 10 is divided into two streams, one of which is connected to the inlet of the cooling circulation pump 11, and the other is connected to the feed of the hydrolysis feed pump 13; the outlet of the cooling circulation pump 11 is connected to the inlet of the circulation cooler 12, and the outlet of the circulation cooler 12 is connected to the residue storage tank 10; the discharge of the hydrolysis feed pump 13 goes to the hydrolysis section.

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