CN217149037U

CN217149037U - Vinylene carbonate production system

Info

Publication number: CN217149037U
Application number: CN202221019526.0U
Authority: CN
Inventors: 梁勇军; 贾凤刚; 钟显威; 刘晓花; 陈孝建; 李明全; 张飞; 韩伟; 龚一贵; 梁振; 李元彬
Original assignee: Shanghai Donggeng Chemical Technology Co ltd
Current assignee: Shanghai Donggeng Chemical Technology Co ltd
Priority date: 2022-04-21
Filing date: 2022-04-21
Publication date: 2022-08-09
Anticipated expiration: 2032-04-21

Abstract

The utility model relates to an organic synthesis technical field, in particular to vinylene carbonate production system. Production system includes one-level reaction unit, second grade reaction unit and purification unit, the one-level reaction unit includes at least one-level photolysis reaction tower, the photolysis reaction tower is provided with ethylene carbonate feed inlet, air inlet, liquid outlet and gas outlet, the second grade reaction unit includes at least one-level reation kettle, reation kettle is provided with feed inlet and discharge gate, the purification unit includes the melting crystallizer, and the liquid outlet of last one-level photolysis reaction tower communicates first order reation kettle's feed inlet, and last one-level reation kettle's discharge gate communicates the melting crystallizer. The utility model discloses a secondary rectification adjustment that will purify the mode by in traditional multistage rectification is the melting crystallization, has improved the purity of end product, has reduced the energy consumption, has improved the economic nature of vinylene carbonate production.

Description

Vinylene carbonate production system

Technical Field

The utility model relates to an organic synthesis technical field, in particular to vinylene carbonate production system.

Background

With the development of society and the progress of science and technology, the demand of energy is also larger and larger, and the problem of energy crisis is more and more prominent. To improve the sustainability of development, green energy has become a research hotspot in recent years.

A lithium ion battery, as a type of secondary battery, mainly operates by movement of lithium ions between a positive electrode and a negative electrode, and during charge and discharge, the lithium ions are inserted and extracted back and forth between the two electrodes, and during charge, the lithium ions are extracted from the positive electrode (usually a lithium-containing compound) and inserted into the negative electrode (usually a carbon material) via an electrolyte, and the negative electrode is in a lithium-rich state, whereas during discharge, the reverse is true. The lithium ion battery has the advantages of large energy density, high voltage, small self-discharge, excellent cycle performance, high charging efficiency, wide working temperature range (-20-60 ℃), long service life, good safety performance and the like.

In the first charge and discharge process of the lithium ion battery, a carbon cathode material in the lithium ion battery on a solid/liquid phase interface can chemically react with organic matters in electrolyte, and then a passivation film (generally called SEI film) is formed on the surface of the cathode, and the passivation film can effectively block penetration of solvent molecules and allow free penetration of lithium ions.

In order to ensure the formation of a compact and stable SEI film, further prolong the cycle life of a lithium ion battery, improve the charge-discharge efficiency of the lithium ion battery, and reduce side reactions in the battery electrolyte, people usually add a film-forming assistant such as vinylene carbonate into the electrolyte.

Currently, the industrial production of vinylene carbonate is generally carried out in the following way: the vinylene carbonate and chlorine are used as raw materials, chlorination reaction is carried out under ultraviolet irradiation to synthesize monochloroethylene carbonate, and then chlorine atoms in the monochloroethylene carbonate are removed by a dehalogenating agent to generate vinylene carbonate. However, the vinylene carbonate prepared by the process has low purity, and cannot meet the application requirements in the fields of lithium ion batteries and the like. In order to improve the purity and meet the application requirements in the fields of lithium ion batteries and the like, in the actual production process, the obtained product is usually placed in a rectifying tower for multistage rectifying and purifying, but the production energy consumption is very high by adopting the method, and the economical efficiency of the amplified production is lower.

SUMMERY OF THE UTILITY MODEL

In view of this, the present invention provides a vinylene carbonate production system to reduce the energy consumption for vinylene carbonate production and improve the economy of vinylene carbonate production.

For solving above technical problem, the utility model provides a vinylene carbonate production system, a serial communication port, including one-level reaction unit, second grade reaction unit and purification unit, the one-level reaction unit includes at least one-level photolysis reaction tower, the photolysis reaction tower is provided with vinylene carbonate feed inlet, air inlet, liquid outlet and gas outlet, the second grade reaction unit includes at least one-level reation kettle, reation kettle is provided with feed inlet and discharge gate, the purification unit includes the melting crystallizer, and the liquid outlet of last one-level photolysis reaction tower communicates the feed inlet of first order reation kettle, and the discharge gate of last one-level reation kettle communicates the melting crystallizer.

The utility model discloses a production system's theory of operation does: the purification mode is adjusted from secondary rectification in the traditional multistage rectification to melt crystallization, so that the purity of the final product is improved, the energy consumption is reduced, and the economical efficiency of vinylene carbonate production is improved.

Optionally, the one-level reaction unit still includes the deacidification tower, the deacidification tower is provided with nitrogen gas import and gas outlet, and it is located communicating pipe between the liquid outlet of last one-level photolysis reaction tower and first order reation kettle's the feed inlet on the way, its one end intercommunication the deacidification tower, the second end are provided with liquid outlet and ethylene carbonate export, liquid outlet intercommunication first order reation kettle's feed inlet, ethylene carbonate export intercommunication the ethylene carbonate feed inlet of photolysis reaction tower.

Optionally, the first-stage reaction unit further comprises a rectifying tower, the rectifying tower is located on a communicating pipeline between the deacidification tower and the first-stage reaction kettle, one end of the rectifying tower is communicated with the deacidification tower, the second end of the deacidification tower is provided with a liquid outlet and a ethylene carbonate outlet, the liquid outlet is communicated with the feed inlet of the first-stage reaction kettle, and the ethylene carbonate outlet is communicated with the ethylene carbonate feed inlet of the photolysis reaction tower. The rectifying tower can remove unreacted Ethylene Carbonate (EC), and the ethylene carbonate can be recycled while the purity of the final product is improved.

Optionally, when the second-stage reaction unit comprises a plurality of stages of reaction kettles, a first centrifugal device is arranged between the adjacent reaction kettles, the first centrifugal device is provided with a liquid inlet, a liquid outlet and a solid outlet, and the liquid inlet and the liquid outlet are respectively communicated with the discharge hole of the previous-stage reaction kettle and the feed inlet of the next-stage reaction kettle.

Optionally, the second-stage reaction unit further includes a washing tower, the washing tower is located on a communicating pipeline between the last-stage reaction kettle and the melt crystallizer, is communicated with a discharge port of the last-stage reaction kettle, is connected with a solid outlet of the centrifugal device through a transmission assembly, and is provided with a liquid outlet end and a solid discharge port, and the liquid outlet end is communicated with the melt crystallizer. Through the washing tower, the chloro triethylamine as a reaction product can be removed, and the purity of the final product is improved.

Optionally, the purification unit further comprises a desolventizing tower and a crude distillation tower which are sequentially communicated, the desolventizing tower and the crude distillation tower are both located on a communicating pipe between the last-stage reaction kettle and the melt crystallizer, the desolventizing tower is communicated with the liquid outlet end of the washing tower, and the crude distillation tower is communicated with the melt crystallizer.

Optionally, the production system further comprises a byproduct recovery unit, the byproduct recovery unit comprises a water absorption tower and an alkali absorption tower which are sequentially communicated, and the water absorption tower is communicated with the gas outlet of the photolysis reaction tower. The chlorination reaction product hydrogen chloride and the redundant chlorine can be respectively recovered through the water absorption tower and the alkali absorption tower to obtain by-products, namely hydrochloric acid and hypochlorite, so that the economy of vinylene carbonate production is further improved, and meanwhile, the environmental protection property of the production process is improved.

Optionally, production system still includes triethylamine recovery unit, triethylamine recovery unit includes drying device and the dissolving tank that is connected through transmission assembly, drying device passes through transmission assembly intercommunication the solid discharge port of scrubbing tower, dissolving tank intercommunication has filter equipment, filter equipment is provided with the liquid discharge port, the liquid discharge port intercommunication reaction tank intercommunication has second centrifugal device, second centrifugal device is provided with the triethylamine export, the triethylamine export intercommunication reation kettle's feed inlet. And the triethylamine recovery unit can realize the recovery and reutilization of triethylamine, and improve the resource utilization rate.

Optionally, the drying device is provided with a dimethyl carbonate exhaust port, and the exhaust port is communicated with the washing tower. The exhaust port of the drying device is communicated with the washing tower, so that the dimethyl carbonate serving as a washing agent can be recycled.

Optionally, the melt crystallizer employs a falling film crystallizer. The utility model discloses in, adopt the falling liquid film crystallizer, can improve the once-through yield of crystallization to further reduce the energy consumption, improve the economic nature of vinylene carbonate production.

Drawings

FIG. 1 is a schematic configuration diagram of a production system of example 1;

FIG. 2 is a schematic configuration diagram of a production system of example 2;

fig. 3 is a schematic configuration diagram of a production system of embodiment 3.

Reference numerals

In the drawings of the utility model, an one-level reaction unit-1, a first photolysis reaction tower-11, a second photolysis reaction tower-12, a deacidification tower-13, a rectification tower-14, a second-level reaction unit-2, a first reaction kettle-21, a first centrifugal device-22, a second reaction kettle-23, a washing tower-24, a purification unit-3, a desolventizing tower-31, a crude distillation tower-32, a 33-falling film crystallizer, a byproduct recovery unit-4, a water washing tower-41, an alkali absorption tower-42, a triethylamine recovery unit-5, a drying device-51, a dissolving tank-52, a filtering device-53, a reaction tank-54, a second centrifugal device-55 and a waste liquid tank-6.

Detailed Description

The following description of the embodiments of the present invention is provided for illustrative purposes, and other advantages and effects of the present invention will be readily apparent to those skilled in the art from the disclosure herein. The present invention can be implemented or applied by other different specific embodiments, and various details in the present specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

The present invention will be described in detail below with reference to specific exemplary embodiments. It should also be understood that the following examples are only for illustrating the present invention and should not be construed as limiting the scope of the present invention, and that the modifications and adjustments made by those skilled in the art according to the above-mentioned contents of the present invention are not essential to the present invention. The specific process parameters and the like of the following examples are also only one example of suitable ranges, i.e., those skilled in the art can select the appropriate ranges through the description herein, and are not limited to the specific values exemplified below.

Example 1

As shown in FIG. 1, the vinylene carbonate production system comprises a primary reaction unit 1, a secondary reaction unit 2, a purification unit 3, a byproduct recovery unit 4 and a triethylamine recovery unit 5.

The first-order reaction unit 1 includes a first photolysis reaction tower 11, a second photolysis reaction tower 12, a deacidification tower 13 and a rectification tower 14, the first photolysis reaction tower 11 and the second photolysis reaction tower 12 are used as a container for chlorination reaction, an ultraviolet light assembly (not shown) and a temperature adjusting assembly (not shown) are arranged in the container, the ultraviolet light assembly is used for providing an ultraviolet light condition for the chlorination reaction, and the temperature adjusting assembly is used for controlling the temperature of the chlorination reaction. Photolysis towers are prior art and are not described in detail herein.

The first photolysis reaction tower 11 and the second photolysis reaction tower 12 are provided with a vinyl carbonate feed inlet, an air inlet, a liquid outlet and an air outlet, raw material molten state vinyl carbonate (EC) can be fed into the first photolysis reaction tower 11 and the second photolysis reaction tower 12 through the vinyl carbonate feed inlet, and chlorine gas can be introduced into the first photolysis reaction tower 11 and the second photolysis reaction tower 12 through the air inlet. The multistage photolysis reaction tower is arranged, so that the chlorine can be completely reacted, and the yield is improved.

The upper part of the deacidification tower 13 is communicated with the discharge hole of the second photolysis reaction tower 12, and the lower part thereof is communicated with the first end of the rectification tower 14. The upper portion of deacidification tower 13 is provided with gas outlet, and its lower part is provided with the nitrogen gas import, can let in nitrogen gas in deacidification tower 13 through the nitrogen gas import, and then get rid of gaseous such as chlorine, hydrogen chloride in the obtained liquid of chlorination, improve the purity of final product simultaneously, can also reduce the energy consumption of follow-up purification process. The deacidification tower is prior art and is not described in detail herein.

The rectifying tower 14 is used for removing the unreacted Ethylene Carbonate (EC) in the chlorination reaction liquid, and the second end of the rectifying tower is provided with a gas phase outlet, a liquid phase outlet and a waste liquid outlet, wherein the gas phase outlet is communicated with the ethylene carbonate feed inlet of the first photolysis reaction tower 11 and/or the second photolysis reaction tower 12, so as to realize the cyclic utilization of the ethylene carbonate. The waste liquid outlet is communicated with a waste liquid tank 6, and the rectifying tower is the prior art and is not described again.

The secondary reaction unit 2 includes a first reaction vessel 21, a first centrifugal device 22, a second reaction vessel 23, and a washing tower 24.

The first reaction vessel 21 and the second reaction vessel 23 are desorption reaction vessels, and both are provided with a feed inlet, a discharge outlet and a temperature regulation assembly (not shown). Triethylamine as a raw material removing agent, butyl-p-cresol (BHT) as a polymerization inhibitor and vinylene carbonate as a solvent can be fed into the first reaction kettle 21 and the second reaction kettle 23 through the feed inlets, chlorinated reaction liquid treated by the rectifying tower 14 can be fed into the first reaction kettle 21 through the feed inlets, and liquid obtained by treatment of the first centrifugal device 22 can be fed into the second reaction kettle 23 through the feed inlets. The temperature adjusting component is used for adjusting the temperature of the materials in the first reaction kettle 21 and the second reaction kettle 23. Through setting up multistage reation kettle, can make the desorption reaction more thorough, improve the yield. The reaction kettle is the prior art and is not described in detail here.

The first centrifugal device 22 is provided with a liquid inlet, a liquid outlet and a solid outlet, and the liquid inlet and the liquid outlet are respectively communicated with the discharge hole of the first reaction kettle 21 and the feed hole of the second reaction kettle 23. The first centrifugal device 22 may be an automatic centrifuge, which is a conventional art and will not be described herein.

The first end of the washing tower 24 is connected with the solid outlet of the first centrifugal device 22 through a transmission component, the first end of the washing tower is communicated with the discharge hole of the second reaction kettle 23, and the first end of the washing tower 24 is also communicated with a dimethyl carbonate liquid inlet pipeline. The detergent dimethyl carbonate can be introduced into the washing tower 24 through a dimethyl carbonate liquid inlet pipeline, the dimethyl carbonate can dissolve vinylene carbonate and cannot dissolve and remove chloro triethylamine salt serving as a reaction product, and therefore recycling of triethylamine is achieved, and the recycling rate of triethylamine is improved. The scrubber is prior art and will not be described further herein.

The purification unit 3 comprises a desolventizing tower 31 and a falling film crystallizer 32 which are communicated in sequence, wherein the falling film crystallizer 32 is communicated with the lower part or the bottom of the desolventizing tower 31 through a circulating pump (not shown). The desolventizing tower and the falling film crystallizer are both in the prior art and are not described in detail herein. The detergent dimethyl carbonate can be removed through the desolventizing tower 31, the purity of the final product is improved, the purity of the final product can be improved through the falling film crystallizer 32, and the energy consumption is reduced. By communicating the falling film crystallizer 32 with the lower part or the bottom of the desolventizing tower 32 through the circulating pump, part of the vinylene carbonate which is not melted and crystallized can be distilled by the desolventizing tower 31 and then enter the falling film crystallizer 33 again for melting and crystallization, so that the yield is improved.

The byproduct recovery unit 4 includes a water absorption tower 41 and an alkali absorption tower 42. The first end of the water absorption tower 41 is communicated with the gas outlet of the first photolysis reaction tower 11, the gas outlet of the second photolysis reaction tower 12 and the gas outlet of the deacidification tower 13, the first end thereof is provided with a water inlet pipeline, and the second end thereof is communicated with the alkali absorption tower 42. Water can be introduced into the water absorption tower 41 through a water inlet pipeline, and the chlorinated reaction product hydrogen chloride can be dissolved by the water to obtain hydrochloric acid. The alkali absorption tower 42 is provided with a waste gas outlet, which is provided with an alkali liquor inlet pipeline (not shown), through which a sodium hydroxide aqueous solution can be introduced into the alkali absorption tower 42, and the sodium hydroxide aqueous solution can react with chlorine gas which does not participate in the chlorination reaction to generate sodium hypochlorite.

The triethylamine recovery unit 5 comprises a drying device 51 and a dissolving tank 52 which are connected through a transmission assembly (not shown), the dissolving tank 52 is communicated with a filtering device 53, the filtering device 53 is provided with a liquid outlet, the liquid outlet is communicated with a reaction tank 54, the reaction tank 54 is communicated with a second centrifugal device 55, the second centrifugal device 55 is provided with a triethylamine outlet, and the triethylamine outlet is communicated with a feed inlet of the first reaction kettle 21 and/or the second reaction kettle 22.

The drying device 51 is connected to the second end of the washing column 24 via a transfer assembly (not shown) which is provided with a dimethyl carbonate (DMC) vent. The drying device 51 is used to dry the chlorotriethylamine salt solid washed by the washing tower 24 to remove a detergent dimethyl carbonate (DMC) attached to the surface thereof. The drying device 51 may be a forced air dryer, which is a prior art and will not be described herein.

The dissolving tank 52 is connected with a water inlet pipeline (not shown), water can be introduced into the dissolving tank 52 through the water inlet pipeline, impurities such as flocculent organic matters attached to the solid surface of the chlorotetramine salt can be dissolved by the water, and then the impurities are filtered and removed through a filtering device 53 communicated with the dissolving tank 52.

The reaction tank 54 is provided with a solid caustic soda inlet, and sodium hydroxide can be added into the reaction tank 54 through the solid caustic soda inlet, so that the chlorotriethylamine salt entering the reaction tank 54 and the sodium hydroxide are subjected to a displacement reaction to generate triethylamine. The triethylamine has low solubility in water, can be separated by a centrifugal device 55 communicated with the reaction tank, and the triethylamine obtained after separation can be sent into the first reaction kettle 21 and/or the second reaction kettle 22 through a triethylamine outlet and continuously participate in the removal reaction, so that the recycling of the triethylamine is realized.

All the communication pipelines are provided with switch valves (not shown).

The working process of the production system of the embodiment is as follows:

ethylene carbonate heated to a molten state in advance is put into the first photolysis reaction tower 11 and the second photolysis reaction tower 12, chlorine gas is introduced into the first photolysis reaction tower 11 and the second photolysis reaction tower 12 through the gas inlet, and the molar ratio of the total amount of chlorine gas to the total amount of ethylene carbonate in the first photolysis reaction tower 11 and the second photolysis reaction tower 12 is 0.4-0.6: 1, 2/3 are respectively accounted for chlorine and ethylene carbonate in the first photolysis reaction tower 11.

And opening the ultraviolet light assembly and the temperature adjusting assembly, heating the ethylene carbonate in the first photolysis reaction tower 11 to 60-70 ℃, wherein the wavelength of the ultraviolet light is less than 500nm, and performing chlorination reaction on chlorine and the ethylene carbonate under the irradiation of the ultraviolet light.

After 1-2h, opening a switch valve on a pipeline between the first photolysis reaction tower 11 and the second photolysis reaction tower 12, opening an ultraviolet light component and a temperature regulating component, heating the ethylene carbonate in the second photolysis reaction tower 12 to 60-70 ℃, wherein the wavelength of the ultraviolet light is less than 500nm, and performing chlorination reaction on chlorine and the ethylene carbonate under the irradiation of the ultraviolet light.

After 1-2h, opening a switch valve on a pipeline between the gas outlet of the first photolysis reaction tower 11 and the gas outlet of the second photolysis reaction tower 12 and the first end of the water absorption tower 41 and a switch valve on a pipeline between the second end of the water absorption tower 41 and the alkali absorption tower 42, introducing water into the water absorption tower 41, introducing a 30 wt% sodium hydroxide aqueous solution into the alkali absorption tower 42, dissolving a chlorination reaction product, namely hydrogen chloride gas, to obtain hydrochloric acid, and reacting the sodium hydroxide aqueous solution with chlorine not participating in the chlorination reaction to generate sodium hypochlorite.

In the process, the on-off valves on the pipelines between the liquid outlet of the first photolysis reaction tower 11 and the liquid outlet of the second photolysis reaction tower 12 and the deacidification tower 13 are opened, the on-off valve on the pipeline between the deacidification tower 13 and the water absorption tower 41 is opened, nitrogen is introduced into the deacidification tower 13, the nitrogen entering the deacidification tower 13 from the lower part is in countercurrent contact with the liquid entering the deacidification tower 13 from the upper part, and then chlorine and hydrogen chloride in the liquid are discharged, so that a liquid phase crude product of monochloro-ethylene carbonate (CEC) is obtained.

Then, opening a switch valve on a pipeline between the deacidification tower 13 and the rectifying tower 14, and rectifying a monochloroethylene carbonate (CEC) liquid phase crude product in the rectifying tower 14 under the conditions that the temperature is 50-60 ℃ and the pressure is 1kPa to further remove unreacted ethylene carbonate completely to obtain high-purity chloroethylene carbonate (CEC); in this process, an on-off valve is opened in a line between the gas phase outlet of the rectifying tower 14 and the first photolysis reaction tower 11 and/or the second photolysis reaction tower 12, and the ethylene carbonate is circulated to the first photolysis reaction tower 11 and/or the second photolysis reaction tower 12 through the line.

After the rectification is completed, opening a switch valve on a pipeline between the rectification tower 14 and the first reaction kettle 21, and feeding a removing agent triethylamine, a polymerization inhibitor butyl-p-cresol (BHT) and a solvent vinylene carbonate into the first reaction kettle 21 and the second reaction kettle 22, wherein the molar ratio of the total amount of triethylamine in the first reaction kettle 21 and the second reaction kettle 22 to the total amount of high-purity chloroethylene carbonate (CEC) is 1: 1-1.5, wherein the molar ratio of the total amount of vinylene carbonate to the total amount of high-purity chloroethylene carbonate (CEC) is 1: 1-1.5, wherein the mass ratio of the total amount of butyl-p-cresol (BHT) to the total amount of high-purity Chlorinated Ethylene Carbonate (CEC) is 0.1-0.5: 100.

in the process, the temperature regulating assembly is opened, the materials in the first reaction kettle 21 are heated to 60-70 ℃, and the high-purity Chlorinated Ethylene Carbonate (CEC) and triethylamine entering the first reaction kettle 21 are subjected to removal reaction for 4-5 hours in the presence of vinylene carbonate to obtain a removal reaction product (chlorinated triethylamine salt).

Then, the on-off valve on the pipeline between the first reaction kettle 21 and the first centrifugal device 22 is opened, and the reaction product is removed and enters the first centrifugal device 22 for centrifugal treatment to obtain liquid and solid.

And then, opening a switch valve on a pipeline between a liquid outlet of the first centrifugal device 22 and the second reaction kettle 23, allowing the liquid obtained by centrifugation to enter the second reaction kettle 23, opening a temperature adjusting component to heat the materials in the second reaction kettle 23 to 60-70 ℃ in the process, and continuously performing a removal reaction on the unreacted materials in the second reaction kettle 21 for 4-5 hours to obtain a removal reaction product (containing the chlorinated triethylamine salt).

Then, the on-off valve on the pipeline between the second reaction kettle 23 and the washing tower 24 is opened, the transmission assembly between the solid outlet of the first centrifugal device 22 and the washing tower 24 is started, and detergent dimethyl carbonate (DMC) is introduced into the washing tower 24, wherein the dimethyl carbonate (DMC) can dissolve vinylene carbonate and cannot dissolve chlorotriethylamine salt, so that the chlorotriethylamine salt is removed, and the purity of a final product is improved.

And then, starting a transmission assembly between the washing tower 24 and the drying device 51, drying the chlorotriethylamine salt solid attached with dimethyl carbonate (DMC) and flocculent organic matters by the drying device 51, removing the dimethyl carbonate (DMC) attached with the chlorotriethylamine salt solid, and enabling the dimethyl carbonate (DMC) to enter the washing tower 24 through a pipeline, so that the cyclic utilization of the dimethyl carbonate (DMC) is realized.

Then, the transmission assembly between the drying device 51 and the dissolving tank 52 is started, water is introduced into the dissolving tank 52, then the switch valve on the pipeline between the dissolving tank 52 and the filtering device 53 is opened, and the liquid mixture enters the filtering device 53 to be filtered to remove flocculent organic matters attached to the chlorotetraethylamine salt.

Then, the on-off valve on the pipeline between the filtering device 53 and the reaction tank 54 is opened, and sodium hydroxide is added into the reaction tank, and the liquid containing the chlorinated triethylamine salt enters the reaction tank 54 and undergoes a displacement reaction with the sodium hydroxide to generate triethylamine.

Then, a switch valve on a pipeline between the reaction tank 54 and the second centrifugal device 55 is opened, the mixed liquid enters the second centrifugal device 55, triethylamine is obtained through separation after filtration treatment, the switch valve on the pipeline between the second centrifugal device 55 and the first reaction kettle 21 and/or the second reaction kettle 22 is opened, and triethylamine liquid enters the first reaction kettle 21 and/or the second reaction kettle 22 through a triethylamine outlet to continuously participate in the removal reaction, so that the triethylamine is recycled.

Opening a switch valve on a pipeline between the washing tower 24 and the desolventizing tower 31, feeding the washed liquid into the desolventizing tower 31, and removing the detergent dimethyl carbonate (DMC) by distillation in the desolventizing tower 31. The temperature of the desolventizing treatment is 30-40 ℃, and the pressure is 6-10 kPa;

subsequently, the line between the desolventizing tower 31 and the falling film crystallizer 32 is opened, and the liquid to be treated (taking a treatment amount of 10kg as an example) enters the falling film crystallizer 33 for melt crystallization, wherein the melt crystallization comprises the steps of crystallization, sweating and melting, and specifically comprises the following steps:

s1: preheating equipment:

pouring 10kg of VC crystallization raw material to be treated with the purity of 97% (temperature is 30-35 ℃) into a raw material tank, starting a falling film crystallizer and circulating cold and heat medium preheating equipment, and controlling the temperature of the circulating cold and heat medium to be 20-25 ℃;

s2: pre-cooling materials: starting a crystallization circulating pump, conveying the VC crystallization raw material in the raw material tank to a falling film crystallizer, and then circularly conveying, wherein the flow of the circulating material is controlled to be 0.2-0.6m3/h, the pressure is controlled to be 0.02-0.07MPa, and the frequency of a motor is controlled to be 13-18Hz, so that the temperature of the circulating material is rapidly reduced to 20-25 ℃;

s3: carrying out first falling film crystallization:

and (3) a crystallization process: reducing the temperature of a circulating cooling and heating medium by 1-3 ℃ step by step at the speed of 0.1-2 ℃/min, controlling the crystallization time to be 80-90min, stopping a crystallization circulating pump, discharging and weighing the mother liquor to obtain 3kg of mother liquor, sampling to obtain the mother liquor with the purity of 91%, filling and storing the mother liquor, accumulating a certain amount of the mother liquor, directly crystallizing to obtain 1.7kg of recovery liquid and 1.3kg of residual liquid, wherein the product purity of the recovery liquid can reach about 98%, the recovery liquid can be crystallized and purified together with the VC crystallization raw material with the purity of 97% next time, and the residual liquid can be sent to a rectification unit;

the sweating process: the temperature of the circulating cooling and heating medium is increased to 18-23 ℃ step by step at the speed of 0.1-2 ℃/min, the temperature of the cooling and heating medium of the falling film crystallization circulating heat preservation system is kept unchanged, the sweating time is controlled to be 40-50min, the sweating liquid is discharged and weighed to obtain 0.5Kg after the sweating is finished, the purity of the sweating liquid is measured by sampling to be 99.2%, and the sweating liquid can be filled, stored and added into the crystallization raw material with the next purity of 97%;

melting process: gradually adjusting the temperature of a cooling medium of the falling film crystallization system to 30-35 ℃ to melt the crystallized product, controlling the melting time for 30min, discharging and weighing the first-stage crystallized product after the melting is finished to obtain 6.5kg, and sampling to obtain the purity of the first-stage crystallized product of 99.4%;

s4: carrying out second falling film crystallization:

and (3) a crystallization process: sending 6.5kg of primary crystallization product with the purity of 99.4% into a falling film crystallizer for circulation, reducing the temperature of a circulating cooling and heating medium by 1-3 ℃ step by step at 0.1-2 ℃/min for crystallization, controlling the crystallization time to be 80-90min, stopping a crystallization circulating pump, discharging and weighing to obtain 0.9kg of secondary mother liquor, sampling to obtain the purity of the secondary mother liquor of 99.3%, and performing crystallization and purification on the secondary mother liquor together with the VC crystallization raw material with the purity of 97% at the next time;

the sweating process: the temperature of the circulating cooling and heating medium is increased to 18-23 ℃ step by step at the speed of 0.1-2 ℃/min, the temperature of the cooling and heating medium of the falling film crystallization circulating heat preservation system is kept unchanged, the sweating time is controlled to be 40-50min, the second-stage sweating liquid is discharged and weighed to obtain 0.6Kg after the sweating is finished, the purity of the second-stage sweating liquid is 99.3% by sampling, and the second-stage sweating liquid can be crystallized and purified together with the VC crystallization raw material with the next purity of 99.4%;

melting process: and (2) gradually adjusting the temperature of a cooling medium of the falling film crystallization system to 30-35 ℃ to melt and crystallize the product, controlling the melting time for 30min, discharging and weighing the secondary crystallization product after the melting is finished to obtain 5kg (the weight of the product is 8.7kg after the recovery liquid and the secondary perspiration liquid are utilized), and sampling to obtain the secondary crystallization product (the vinylene carbonate crystal on the tube wall of the crystallization tube of the falling film crystallizer obtained by circulating and crystallizing the vinylene carbonate crystal on the tube wall of the crystallization tube of the falling film crystallizer after the vinylene carbonate crystal on the tube wall of the crystallization tube of the falling film crystallizer is melted in the first crystallization process) with the purity of 99.99%.

In this example, the purity was measured in accordance with GB/T27801-2011 vinylene carbonate, which is the same as below.

Example 2

As shown in FIG. 2, this example is different from example 1 in that: a crude distillation column 33 is provided on a communicating pipe between the desolventizing column 31 and the falling film crystallizer 32, and the falling film crystallizer 32 communicates with the lower part or bottom of the crude distillation column 33 via a circulating pump (not shown). The crude distillation tower 33 can remove impurities such as polymerization inhibitor butyl-p-cresol (BHT) and poly (ethylene carbonate) by distillation, and further improve the purity of the final product. The temperature of the crude distillation treatment is 50-60 ℃, and the pressure is 2-4 kPa;

s1: pouring 10kg of VC crystallization raw material to be treated with the purity of 98% (the temperature is 30-35 ℃) into a raw material tank, starting a falling film crystallizer and circulating cold and heat medium preheating equipment, and controlling the temperature of the circulating cold and heat medium to be 20-23 ℃;

s2: pre-cooling materials: starting a crystallization circulating pump, conveying the VC crystallization raw material in the raw material tank to the falling film crystallizer, and then circularly conveying, wherein the flow of a circulating material is controlled to be 0.2-0.6m3/h, the pressure is controlled to be 0.02-0.07MPa, and the frequency of a motor is controlled to be 13-18Hz, so that the temperature of the circulating material is rapidly reduced to 20-25 ℃;

s3: carrying out first falling film crystallization:

and (3) a crystallization process: reducing the temperature of the circulating cooling and heating medium to 1-3 ℃ step by step at the speed of 0.1-2 ℃/min, controlling the crystallization time to be 80-90min, stopping a crystallization circulating pump, discharging and weighing mother liquor to obtain 1.8kg of direct crystallization to obtain 1.2kg of recovery liquid and 0.6kg of residual liquid, wherein the product purity of the recovery liquid can reach about 98.5%, the recovery liquid can be crystallized and purified together with the VC crystallization raw material with the next purity of 98%, and the residual liquid can be sent to a secondary rectification unit;

sweating process: the temperature of the circulating cooling and heating medium is increased to 18-23 ℃ step by step at the speed of 0.1-2 ℃/min, the temperature of the cooling and heating medium of the falling film crystallization circulating heat preservation system is kept unchanged, the sweating time is controlled to be 40-50min, the first-stage sweating liquid is discharged and weighed to obtain 0.3kg after the sweating is finished, the purity of the first-stage sweating liquid is measured by sampling to be 99.5%, and the first-stage sweating liquid can be filled, stored and added into the crystallization raw material with the next purity of 98%;

melting process: gradually adjusting the temperature of a cooling medium of the falling film crystallization system to 30-35 ℃ to melt a crystallization product, controlling the melting time for 30min, discharging and weighing a first-stage crystallization product after the melting is finished to obtain 7.9kg, and sampling to measure that the purity of the first-stage crystallization product is 99.4%;

s4: carrying out second falling film crystallization:

and (3) a crystallization process: sending 7.9kg of primary crystallization products with the purity of 99.4% into a falling film crystallizer for circulation, reducing the temperature of a circulating cooling and heating medium by 1-3 ℃ step by step at 0.1-2 ℃/min for crystallization, controlling the crystallization time to be 80-90min, stopping a crystallization circulating pump, discharging and weighing to obtain 1.6kg of secondary mother liquor, sampling to obtain the purity of the secondary mother liquor of 98.6%, and performing crystallization and purification on the secondary mother liquor and a VC crystallization raw material with the next purity of 98%;

the sweating process: the temperature of the circulating cooling and heating medium is increased to 18-23 ℃ step by step at the speed of 0.1-2 ℃/min, the temperature of the cooling and heating medium of the falling film crystallization circulating heat preservation system is kept unchanged, the sweating time is controlled to be 40-50min, the second-stage sweating liquid is discharged and weighed to obtain 0.5Kg after the sweating is finished, the purity of the second-stage sweating liquid is 99.3% after sampling, and the second-stage sweating liquid can be crystallized and purified together with a first-stage crystallization product with the next purity of 99.4%;

melting process: gradually adjusting the temperature of a cooling medium of the falling film crystallization system to 30-35 ℃ to melt the crystallized product, controlling the melting time for 30min, discharging and weighing the secondary crystallized product after the melting is finished to obtain 5.8kg, and sampling to obtain the purity of the secondary crystallized product of 99.99%;

s4: carrying out third falling film crystallization:

and (3) a crystallization process: 5.8kg of secondary crystallization product with the purity of 99.99 percent is sent into a falling film crystallizer for circulation, the temperature of a circulating cooling and heating medium is reduced by 1 to 3 ℃ step by step at the speed of 0.1 to 2 ℃/min for crystallization, the crystallization time is controlled to be 80 to 90min, a crystallization circulating pump is stopped, 0.9kg of tertiary mother liquor is obtained by discharge and weighing, the purity of the tertiary mother liquor is 99.92 percent by sampling, and the tertiary mother liquor can be crystallized and purified together with the primary crystallization product with the purity of 99.4 percent at the next time;

the sweating process: the temperature of the circulating cooling and heating medium is increased to 18-23 ℃ step by step at the speed of 0.1-2 ℃/min, the temperature of the cooling and heating medium of the falling film crystallization circulating heat preservation system is kept unchanged, the sweating time is controlled to be 40-50min, the sweating is finished, the sweating liquid of the third-stage is discharged and weighed to obtain 0.7Kg, the purity of the third-stage sweating liquid is measured by sampling to be 99.95%, and the third-stage sweating liquid can be crystallized and purified together with the next second-stage crystallization product with the purity of 99.99%;

melting process: gradually adjusting the temperature of a cooling medium of the falling film crystallization system to 30-35 ℃ to melt and crystallize the product, controlling the melting time for 30min, discharging and weighing the third-stage crystallized product after the melting is finished to obtain 4.2kg (the weight of the product is about 7.3kg after the recycling liquid, the second-stage mother liquid, the first-stage mother liquid, the second-stage mother liquid and the third-stage sweat are utilized), and sampling to obtain the purity of the second-stage crystallized product which is 99.995%;

the energy consumption for purifying the VC crude product with the purity of 60 percent to the high-purity VC with the purity of 99.995 percent is 2500kg of steam per ton of the product.

Temperature adjustment in the crystallization process:

the first-stage crystallization is rapidly cooled to 35-22 ℃ and slowly cooled to 22-0 ℃;

the second and third-stage crystallization is rapidly cooled to 35-22 ℃ and slowly cooled to 22-5 ℃.

Adjusting the temperature of a cooling medium of a falling film crystallization system by sweating:

the first-stage crystallization is rapidly heated to 0-18 ℃ and slowly heated to 18-22.5 ℃;

the second and third-stage crystallization are rapidly heated to 5-18 ℃ and slowly heated to 18-22.5 ℃.

Keeping the temperature of a cold and heat medium of the falling film crystallization circulation heat preservation system unchanged, controlling the sweating time to be 40-50min, and discharging sweat after sweating, weighing and sampling.

Example 3

As shown in FIG. 3, this example is different from example 2 in that: the first-stage reaction unit 1 does not comprise a rectifying tower 14 and a waste liquid tank 6, the deacidification tower 13 is communicated with a feed inlet of a first reaction kettle 21, the second-stage reaction unit 2 does not comprise a first centrifugal device 22, and a discharge hole of the first reaction kettle 21 is communicated with a feed inlet of a second reaction kettle 23; the molar ratio of the total chlorine gas to the total ethylene carbonate in the first photolysis reaction tower 11 and the second photolysis reaction tower 12 is 0.4-0.6: 2-3, vinylene carbonate is not introduced into the first reaction kettle 21 and the second first reaction kettle 22, but the ethylene carbonate which is not completely reacted in the chlorination reaction step is used as a solvent in the removal reaction step.

In this embodiment, no new solvent is introduced in the removal reaction step, but the unreacted ethylene carbonate in the chlorination reaction step is used as the solvent, so that the rectification step in the first reaction unit 1 is omitted, and the energy consumption is further reduced.

The above embodiments are merely illustrative of the principles and effects of the present invention, and are not to be construed as limiting the invention. It will be apparent to those skilled in the art that modifications and variations can be made to the above-described embodiments without departing from the spirit and scope of the invention, and it is intended that all equivalent modifications and variations be covered by the appended claims without departing from the spirit and scope of the invention.

Claims

1. The utility model provides a vinylene carbonate production system, a serial communication port, including one-level reaction unit, second grade reaction unit and purification unit, one-level reaction unit includes at least one-level photolysis reaction tower, the photolysis reaction tower is provided with ethylene carbonate feed inlet, air inlet, liquid outlet and gas outlet, second grade reaction unit includes at least one-level reation kettle, reation kettle is provided with feed inlet and discharge gate, the purification unit includes the melting crystallizer, and the liquid outlet of last one-level photolysis reaction tower communicates first order reation kettle's feed inlet, and last one-level reation kettle's discharge gate communicates the melting crystallizer.

2. The production system of claim 1, wherein the primary reaction unit further comprises a deacidification tower, and the deacidification tower is provided with a nitrogen inlet and a gas outlet which are positioned on a communicating pipeline between a liquid outlet of the last photolysis reaction tower and a feed inlet of the first reaction kettle.

3. The production system according to claim 2, wherein the primary reaction unit further comprises a rectifying tower, the rectifying tower is located on a communicating pipeline between the deacidification tower and the first-stage reaction kettle, one end of the rectifying tower is communicated with the deacidification tower, the second end of the rectifying tower is provided with a liquid outlet and a ethylene carbonate outlet, the liquid outlet is communicated with the feeding port of the first-stage reaction kettle, and the ethylene carbonate outlet is communicated with the ethylene carbonate feeding port of the photolysis reaction tower.

4. The production system of claim 1, wherein when the secondary reaction unit comprises a plurality of stages of reaction kettles, a first centrifugal device is arranged between adjacent reaction kettles, the first centrifugal device is provided with a liquid inlet, a liquid outlet and a solid outlet, and the liquid inlet and the liquid outlet are respectively communicated with the discharge hole of the previous stage of reaction kettle and the feed hole of the next stage of reaction kettle.

5. The production system of claim 4, wherein the secondary reaction unit further comprises a washing tower, the washing tower is positioned on a communication pipeline between the last stage reaction kettle and the melt crystallizer, the washing tower is communicated with a discharge port of the last stage reaction kettle and is connected with a solid outlet of the centrifugal device through a transmission assembly, a liquid outlet end and a solid discharge port are arranged, and the liquid outlet end is communicated with the melt crystallizer.

6. The production system of claim 5, wherein the purification unit further comprises a desolventizing column and a crude-distilling column connected in sequence, the desolventizing column and the crude-distilling column are both located on a communicating pipe between the last-stage reaction tank and the crystallizer, the desolventizing column is connected to a liquid outlet end of the washing column, and the crude-distilling column is connected to the crystallizer.

7. The production system according to claim 6, further comprising a byproduct recovery unit including a water absorption tower and an alkali absorption tower in communication with each other in sequence, wherein the water absorption tower is in communication with the gas outlet of the photolysis reaction tower.

8. The production system of claim 7, further comprising a triethylamine recovery unit, wherein the triethylamine recovery unit comprises a drying device and a dissolving tank which are connected through a transmission assembly, the drying device is communicated with the solid discharge port of the washing tower through the transmission assembly, the dissolving tank is communicated with a filtering device, the filtering device is provided with a liquid discharge port, the liquid discharge port is communicated with a reaction tank, the reaction tank is communicated with a second centrifugal device, the second centrifugal device is provided with a triethylamine outlet, and the triethylamine outlet is communicated with the feed inlet of the reaction kettle.

9. The production system of claim 8, wherein the drying device is provided with a dimethyl carbonate vent, the vent communicating with the scrubber.

10. The production system of claim 1, wherein the melt crystallizer is a falling film crystallizer.