Process and device for producing vinyl ethyl ether by acetal cleavage

Abstract

The application provides an acetal cracking process and device for producing vinyl ethyl ether, which sets a cracking reaction section and a product refining section, reduces the generation of by-products by regulating and controlling the cracking reaction conditions, and comprises a cracking reactor, a quenching tower, a first vinyl ethyl ether refining tower, an ethanol recovery tower and a second vinyl ethyl ether refining tower; the application takes the experimental phase equilibrium data as the basis, optimizes the distillation separation sequence and the distillation operation parameters, and guarantees the product purity; a side line production pipeline is arranged on the first vinyl ethyl ether refining tower to take out the ethyl acetate impurities and send them to a boundary area outside separation and purification device; meanwhile, an ethanol separation tower is arranged to recover ethanol, which can be recycled to the acetal synthesis process, or be sent to the quenching tower to be used as a quenching medium to reduce the raw material cost and the waste liquid discharge amount; by arranging two-stage distillation towers, high-quality vinyl ethyl ether products with a purity of greater than or equal to 99% can be obtained, which can meet the production requirements of fine chemicals.

Description

Technical Field

[0001] This invention relates to a process for producing vinyl ethyl ether, and particularly to a process and apparatus for producing vinyl ethyl ether by acetal cracking. Background Technology

[0002] Vinyl ethyl ether, with the chemical formula C4H8O, is a flammable and volatile colorless liquid. At room temperature, it is a colorless, transparent liquid with a characteristic sweet odor of ethers. Its density is 0.753–0.754 g / cm³ at 20–25 °C. It is slightly soluble in water and petroleum ether, insoluble in glycerol, and miscible with most organic solvents such as ethanol, ether, acetone, and chloroform. Vinyl ethyl ether is flammable and explosive, capable of forming explosive mixtures with air, with an explosion limit of 1.7%–28.0% (V). It is highly reactive, readily undergoing polymerization, addition, and oxidation reactions. Vinyl ethyl ether is an important organic chemical raw material, widely used in chemical, pharmaceutical, and coating industries, and can be used to produce products such as glutaraldehyde, sulfadiazine, fragrances, adhesives, and polyvinyl ethyl ether. In the production of fine chemicals such as sulfadiazine and glutaraldehyde, impurities such as acetaldehyde and ethanol in vinyl ethyl ether can easily induce side reactions. Therefore, the purity of vinyl ethyl ether is required to be ≥99% when producing these chemicals.

[0003] Currently, the most widely used industrial method for producing vinyl ethyl ether is the acetylene process. This method involves the addition reaction of acetylene and ethanol to produce vinyl ethyl ether. However, acetylene, the raw material in this method, is highly flammable and explosive. It easily forms explosive mixtures when mixed with air, and is even more prone to explosion under high-pressure reaction conditions, posing a very high safety risk to industrial production. Furthermore, this process involves numerous side reactions, resulting in low raw material utilization, and the preparation of acetylene generates a significant amount of pollutants. Besides the acetylene process, acetal pyrolysis is another important industrial method for producing vinyl ethyl ether. This method uses acetal as a raw material, which undergoes a catalytic pyrolysis reaction to produce vinyl ethyl ether and ethanol. Compared to the widely used acetylene process, the acetal pyrolysis method eliminates the need for highly hazardous raw materials such as acetylene, resulting in higher production safety. The pyrolysis reaction conditions are relatively mild, with fewer side reactions, and subsequent separation and purification are easier. Simultaneously, the generated byproduct ethanol can be recovered and reused. The recovered ethanol undergoes a condensation reaction to regenerate acetal, achieving ethanol recycling. This process has a simple operation flow, strong process stability, and promising prospects for industrial production.

[0004] Patent CN 111348991 A discloses a process for producing vinyl ethers via acetal cracking. This patent uses a rare-earth metal-modified calcium phosphate catalyst to catalyze the cracking reaction and details the operating parameters of the cracking reaction section. However, it lacks a detailed design for the distillation and purification section, and does not specify key aspects such as the distillation process and operational control. The product separation and purification process also lacks clearly defined operating parameters. Patent US 4014941 discloses a process for preparing α,β-unsaturated ethers via acetal cracking using calcium phosphate as a catalyst. This catalyst exhibits high catalytic activity, excellent product selectivity, and a lifespan exceeding 2000 hours. However, this patent only focuses on optimizing the catalytic reaction process and does not address the design of the distillation section required for industrial production.

[0005] US Patent 2779720 discloses a distillation process for vinyl ethers, achieving efficient separation of C8 and higher vinyl ethers from alcohols through azeotropic distillation. However, this process is only applicable to C8 and higher vinyl ether systems and does not address the separation of vinyl ethers from other impurities such as ethylene, acetal, and ethyl acetate. Furthermore, the highest purity of the product obtained by this process is only 98.8%. US Patent 7670464 B2 discloses a method for separating vinyl ethers and alcohols by designing two distillation columns under different pressures. However, this patent only designs the distillation section for vinyl ethers and alcohols and does not consider the separation and recovery of components such as ethylene, acetaldehyde, ethyl acetate, and unreacted acetal in the cracking product system. Patent CN 122167269 A discloses a process for producing vinyl ethyl ether by liquid-phase cracking of acetal. This patent uses a combination of flash evaporation and distillation to purify vinyl ethyl ether, but this process can only produce vinyl ethyl ether products with a purity of 98% to 99%, and it is difficult to produce vinyl ethyl ether products with a purity of ≥99%.

[0006] In summary, the current process mainly has the following problems:

[0007] Currently disclosed acetal pyrolysis processes only design separation schemes for vinyl ethyl ether and ethanol, without considering the separation of components such as ethylene, acetaldehyde, ethyl acetate, and unreacted acetal in the pyrolysis product system. The resulting vinyl ethyl ether purity is <99%, failing to achieve the separation of acetal pyrolysis impurities and the production of high-purity vinyl ethyl ether. No technology has yet disclosed a process for producing vinyl ethyl ether via acetal gas-phase pyrolysis, achieving impurity separation and byproduct recovery. Summary of the Invention

[0008] This invention provides a process and apparatus for producing vinyl ethyl ether from acetal via cracking. It designs a process and apparatus for producing vinyl ethyl ether from acetal via cracking that is coupled with catalytic cracking and separation purification. The process includes a cracking reaction section and a product refining section. By controlling the cracking reaction conditions, the generation of by-products is reduced. The distillation separation process and operating parameters are optimized based on the composition of the cracking products and phase equilibrium data, simplifying the separation process and reducing equipment investment and production costs. This invention includes a quench tower for removing non-condensable gaseous impurities such as ethylene and acetaldehyde and for rapidly cooling the cracked gas, reducing the separation burden on subsequent distillation columns. The key phase equilibrium data obtained by this invention are shown in the appendix. Figure 1 The atmospheric pressure-temperature-composition phase diagrams of vinyl ethyl ether-acetal, vinyl ethyl ether-ethanol, and vinyl ethyl ether-water shown in Figure 3 are used to obtain the corresponding binary interaction parameters by fitting phase equilibrium data. Based on this, the distillation and purification section is designed and the operating parameters of each distillation column are determined to ensure the stable production of high-grade vinyl ethyl ether. A side-stream outlet pipe is set at the top of the first vinyl ethyl ether purification column to collect ethyl acetate from the acetal raw material impurities and send it to the ethyl acetate purification unit outside the boundary. This invention sets up a first and second vinyl ethyl ether purification column to synergistically separate and purify vinyl ethyl ether. The vinyl ethyl ether product obtained meets the requirements of 99% purity high-grade product in the "Enterprise Standard of Hubei Jinghong Biotechnology Co., Ltd. - Vinyl Ethyl Ether" (Q / HBJH 7-2020), and meets the production requirements of fine chemicals such as sulfadiazine and glutaraldehyde.

[0009] To achieve the above-mentioned objectives, the technical solution of the present invention is as follows:

[0010] A process for producing vinyl diethyl ether by acetal cracking includes the following steps:

[0011] (1) Includes the step of heating acetal to the reaction temperature and continuously feeding it into the reactor, and cracking it under the catalysis of calcium phosphate to generate a mixed product of vinyl ethyl ether and ethanol;

[0012] (2) Includes the steps of sending all the products from the reaction section to the quench tower of the refining section, rapidly removing non-condensable gas impurities under normal pressure, and rapidly cooling the cracked gas.

[0013] (3) Includes the step of sending the liquid phase mixture from the bottom of the quench tower to the first purification tower for vinyl ethyl ether, separating vinyl ethyl ether and ethanol by distillation, and separating ethyl acetate through a side-stream pipeline;

[0014] (4) Includes the step of sending the ethanol mixture from the bottom of the first vinyl ether refining tower to an ethanol recovery tower to recover and recycle the ethanol;

[0015] (5) Includes the step of sending the vinyl ethyl ether mixture at the top of the first vinyl ethyl ether purification tower to the second vinyl ethyl ether purification tower for further purification to obtain a superior vinyl ethyl ether product.

[0016] The step (1) is as follows: the raw material acetal is preheated to the reaction temperature and continuously fed into an isothermal gas-phase cracking reactor; the operating pressure of the gas-phase cracking reactor is 0.10 ~ 0.15 MPaA, the reaction temperature is 275.0 ~ 325.0 ℃, and the mass hourly space velocity of acetal is 3 ~ 9 h⁻¹; acetal undergoes a cracking reaction under the catalysis of calcium phosphate to generate vinyl ethyl ether and ethanol, and finally a mixed reaction product with vinyl ethyl ether and ethanol as the main components is obtained.

[0017] The step (2) is as follows: the high-temperature mixed reaction product discharged from the outlet of the gas phase cracking reactor is directly fed into the bottom of the quench tower; the operating pressure of the quench tower is 0.10 ~ 0.15 MPaA, the quench medium is ethanol, and the cooling rate is controlled at 25 ~ 30 ℃ / s; after vapor-liquid separation, the liquid phase after rapid cooling is a mixture of vinyl ether with light components removed, which is sent to the subsequent distillation section, and the gas is non-condensable gas such as ethylene and acetaldehyde, which is sent to the flare system for processing.

[0018] Step (3) involves feeding the mixed liquid material from the bottom of the quench tower into the first purification tower of vinyl ethyl ether in the product purification section. The operating pressure of the first purification tower is 0.07 ~ 0.12 MPaA, the reflux ratio is 15 ~ 25, the top temperature is 30.0 ~ 38.0 ℃, and the bottom temperature is 80.0 ~ 90.0 ℃. At ℃; the overhead gas from the first purification tower of vinyl ethyl ether is condensed by a multi-stage condenser, and the liquid vinyl ethyl ether is sent to the reflux tank of the first purification tower of vinyl ethyl ether. All non-condensable gases are sent to the flare system for treatment. The liquid vinyl ethyl ether in the reflux tank of the first purification tower of vinyl ethyl ether is sent to the distributor of the first purification tower of vinyl ethyl ether by a vinyl ethyl ether mixture transfer pump. Part of the liquid vinyl ethyl ether mixture is sent to the second purification tower of vinyl ethyl ether, and the remaining liquid mixture is returned to the top of the first purification tower of vinyl ethyl ether as reflux liquid. At the same time, the side stream of the first purification tower of vinyl ethyl ether produces a mixture of ethyl acetate with a mass flow rate of 40.0 ~ 60.0 kg / hr, which is sent to the ethyl acetate purification unit outside the boundary to obtain high-purity ethyl acetate. The bottom of the tower yields a mixture of ethanol rich in ethanol, unreacted acetal, and other high-boiling impurities. All of this material is sent to the ethanol recovery tower for ethanol purification and recovery.

[0019] Step (4) involves the following: the ethanol mixture from the bottom of the first vinyl ethyl ether refining column is fed into the ethanol recovery column via an ethanol recovery column feed pump for distillation separation; the operating pressure of the ethanol recovery column is 0.08 ~ 0.12 MPaA, the reflux ratio is 4 ~ 8, the top temperature is 75.0 ~ 80.0 ℃, and the bottom temperature is 95.0 ~ 105.0 ℃. ℃; After the overhead gas of the ethanol recovery tower is condensed by a multi-stage condenser, the liquid ethanol is sent to the ethanol recovery tower reflux tank, and all other non-condensable gases are sent to the flare system for treatment. The liquid ethanol in the ethanol recovery tower reflux tank is sent to the ethanol recovery tower distributor by the ethanol product transfer pump. Part of the ethanol is collected as a product and can be sent to the acetal synthesis process outside the boundary for recycling without additional treatment, or it can be cooled and sent to the quench tower as a quench medium; the remaining part of the ethanol is returned to the top of the ethanol recovery tower as reflux liquid; at the same time, the bottom of the ethanol recovery tower produces high-boiling waste liquid, which is sent to the waste liquid treatment device for centralized treatment by the first high-boiling waste liquid transfer pump.

[0020] Step (5) involves feeding the vinyl ethyl ether mixture from the product pipeline of the first vinyl ethyl ether refining tower directly into the second vinyl ethyl ether refining tower for further distillation and purification. The operating pressure of the second vinyl ethyl ether refining tower is 0.08 ~ 0.12 MPaA, the reflux ratio is 7 ~ 11, the top temperature is 30.0 ~ 37.0 ℃, and the bottom temperature is 45.0 ~ 50.0 ℃. At ℃; the overhead gas from the second purification tower of vinyl ethyl ether is condensed by a multi-stage condenser, and the liquid vinyl ethyl ether is sent to the reflux tank of the second purification tower of vinyl ethyl ether. All other non-condensable gases are sent to the flare system for treatment. The liquid vinyl ethyl ether in the reflux tank of the second purification tower of vinyl ethyl ether is sent to the distributor of the second purification tower of vinyl ethyl ether via a premium vinyl ethyl ether transfer pump. Part of the liquid vinyl ethyl ether is collected as premium vinyl ethyl ether, and the rest is returned to the top of the second purification tower of vinyl ethyl ether as reflux liquid. At the same time, a small amount of high-boiling impurities are collected from the bottom of the second purification tower of vinyl ethyl ether and sent to the waste liquid treatment device via a second high-boiling waste liquid transfer pump.

[0021] The apparatus for producing vinyl ethyl ether by acetal cracking of the present invention includes a gas-phase cracking reactor (R101), a quench tower (T101), a first vinyl ethyl ether purification tower (T102), an ethanol recovery tower (T103), and a second vinyl ethyl ether purification tower (T104). The outlet of the gas-phase cracking reactor (R101) is connected to the bottom inlet of the quench tower (T101), the top outlet of the quench tower (T101) is connected to a flare system, and the bottom outlet of the quench tower (T101) is connected to the inlet of the first vinyl ethyl ether purification tower (T102). The first vinyl ethyl ether purification tower (T102) is equipped with a side-stream extraction pipe, which connects to an ethyl acetate purification unit outside the boundary area. The first vinyl ethyl ether purification tower (T102)... The top of the column is connected to the inlet of the first purification column of vinyl ethyl ether, the distributor (F101), and the outlet of the distributor (F101) is simultaneously connected to the upper inlet of the first purification column of vinyl ethyl ether (T102) and the feed inlet of the second purification column of vinyl ethyl ether (T104). The bottom outlet of the first purification column (T102) is connected to the feed inlet of the ethanol recovery column (T103). An ethanol product pipeline is installed at the top of the ethanol recovery column (T103), which connects to the acetal synthesis process outside the boundary area. The bottom outlet of the ethanol recovery column (T103) is connected to a waste liquid treatment device. A superior product pipeline of vinyl ethyl ether is installed at the top of the second purification column of vinyl ethyl ether (T104), and the bottom outlet of the second purification column of vinyl ethyl ether (T104) is connected to a waste liquid treatment device.

[0022] The specific explanation is as follows:

[0023] A process for producing vinyl diethyl ether by acetal cracking includes the following steps:

[0024] (1) The process includes the steps of heating acetal to the reaction temperature and continuously feeding it into a reactor, where it is cracked under the catalysis of calcium phosphate to produce a mixed product of vinyl ethyl ether and ethanol: the raw material acetal is preheated to the reaction temperature and continuously fed into an isothermal gas phase cracking reactor (R101); under constant temperature and pressure conditions in the reactor, acetal undergoes a cracking reaction under the catalysis of calcium phosphate to produce vinyl ethyl ether and ethanol, and finally a mixed reaction product with vinyl ethyl ether and ethanol as the main components is obtained;

[0025] (2) Includes the steps of sending all the products from the reaction section to the quench tower of the refining section, rapidly removing non-condensable gas impurities under normal pressure, and rapidly cooling the cracked gas: the high-temperature mixed reaction products discharged from the outlet of the gas phase cracking reactor (R101) are directly sent to the bottom of the quench tower (T101); after vapor-liquid separation, the liquid phase after rapid cooling is a mixture of vinyl ethyl ether with light components removed, which is sent to the subsequent distillation section, and the gas is non-condensable gases such as ethylene and acetaldehyde, which are all sent to the flare system for processing;

[0026] (3) Includes the step of sending the liquid phase mixture from the bottom of the quench tower (T101) to the first purification tower (T102) for vinyl ethyl ether, separating vinyl ethyl ether and ethanol by distillation, and separating ethyl acetate through a side-stream pipeline;

[0027] (4) Includes the step of sending the ethanol mixture in the bottom of the first vinyl ether purification tower (T102) to the ethanol recovery tower (T103) to recover ethanol and recycle it;

[0028] (5) The step of sending the vinyl ethyl ether mixture at the top of the first vinyl ethyl ether purification column (T102) to the second vinyl ethyl ether purification column (T104) for further purification to obtain a superior vinyl ethyl ether product.

[0029] This invention provides a novel apparatus for the production of vinyl ethyl ether;

[0030] This includes a gas-phase cracking reactor R101, a quench tower T101, a first-stage condenser for vinyl ethyl ether (DEE) T102, a first-stage condenser for DEE E101, a first-stage vapor-liquid separator for DEE E101, a second-stage condenser for DEE E102, a second-stage vapor-liquid separator for DEE E102, a reflux tank for DEE E103, a feed pump for the ethanol recovery tower P101, a mixture transfer pump for DEE E102, a distributor for DEE E101, an ethanol recovery tower T103, a first-stage condenser for the ethanol recovery tower E103, a first-stage vapor-liquid separator for the ethanol recovery tower V104, and a second-stage condenser for the ethanol recovery tower. E104, Secondary vapor-liquid separator of ethanol recovery tower; V105, reflux tank of ethanol recovery tower; V106, First high-boiling waste liquid transfer pump; P103, Ethanol product transfer pump; P104, Diverter of ethanol recovery tower; F102, Secondary purification tower of vinyl ethyl ether; T104, First-stage condenser of vinyl ethyl ether; E105, First-stage vapor-liquid separator of vinyl ethyl ether; V107, Secondary condenser of vinyl ethyl ether; E106, Secondary vapor-liquid separator of vinyl ethyl ether; V108, Secondary vapor-liquid separator of vinyl ethyl ether; V109, reflux tank of vinyl ethyl ether; Secondary high-boiling waste liquid transfer pump; P105, Premium vinyl ethyl ether transfer pump; P106, Diverter of vinyl ethyl ether; F103.

[0031] In the above technical solution, the specific implementation of step (1) is as follows: the raw material acetal is preheated to the reaction temperature and continuously fed into the isothermal gas-phase cracking reactor R101; the operating pressure of the gas-phase cracking reactor is 0.10 ~ 0.15 MPaA, the reaction temperature is 275.0 ~ 325.0 ℃, and the mass hourly space velocity of acetal is 3 ~ 9 h⁻¹. Under constant temperature and pressure conditions in the reactor, acetal undergoes a cracking reaction under the catalysis of calcium phosphate to generate vinyl ethyl ether and ethanol, ultimately obtaining a mixed reaction product with vinyl ethyl ether and ethanol as the main components.

[0032] In the above technical solution, the specific implementation of step (2) is as follows: the high-temperature mixed reaction product discharged from the outlet of the gas phase cracking reactor R101 is directly fed into the bottom of the quench tower T101; the operating pressure of the quench tower is 0.10 ~ 0.15 MPaA, the quench medium is ethanol, and the cooling rate is controlled at 25 ~ 30 ℃ / s. After vapor-liquid separation, the liquid phase is a mixed liquid phase material of vinyl ethyl ether with light components removed, which is sent to the subsequent distillation section, and the gas is non-condensable gases such as ethylene and acetaldehyde, which are all sent to the flare system for processing.

[0033] In the above technical solution, the specific implementation of step (3) is as follows: the mixed liquid material collected from the bottom of the quench tower T101 is sent to the first purification tower T102 of the vinyl ethyl ether in the product purification section. The operating pressure of the first purification tower of vinyl ethyl ether is 0.07 ~ 0.12 MPaA; the reflux ratio is 15 ~ 25; the top temperature is 30.0 ~ 38.0 ℃; and the bottom temperature is 80.0 ~ 90.0 ℃. The overhead gas from the first purification column T102 of the vinyl ethyl ether (VEE) is condensed in the first-stage condenser E101 and then enters the first-stage vapor-liquid separator V101. The liquid VEE in V101 enters the reflux tank V103. Meanwhile, the non-condensable gas in V101 enters the second-stage condenser E102 for further condensation, and then enters the second-stage vapor-liquid separator V102. The liquid VEE in V102... The non-condensable gases in the first reflux tank V103 of the vinyl ethyl ether refining tower are all sent to the flare system for processing. The liquid vinyl ethyl ether in the first reflux tank V103 is sent to the first ethyl ether refining tower distributor F101 via the vinyl ethyl ether mixture transfer pump P102. Part of the liquid vinyl ethyl ether mixture is sent to the second ethyl ether refining tower, and the remaining liquid mixture is returned to the top of the first ethyl ether refining tower T102 as reflux liquid. At the same time, an ethyl acetate mixture with a mass flow rate of 40.0 ~ 60.0 kg / hr is collected from the side stream of the first ethyl ether refining tower T102 and sent to the ethyl acetate purification unit outside the boundary to obtain high-purity ethyl acetate. The bottom of the tower yields an ethanol mixture rich in ethanol, unreacted acetal, and other high-boiling impurities. All of this material is sent to the ethanol recovery tower T103 for ethanol purification and recovery.

[0034] In the above technical solution, the specific implementation of step (4) is as follows: the ethanol mixture from the bottom of the first refining tower T102 of the vinyl ethyl ether is fed into the ethanol recovery tower T103 for distillation separation via the ethanol recovery tower feed pump P101. The operating pressure of the ethanol recovery tower is 0.08 ~ 0.12 MPaA, the reflux ratio is 4 ~ 8, the top temperature is 75.0 ~ 80.0℃, and the bottom temperature is 95.0 ~ 105.0℃. The overhead gas from ethanol recovery tower T103 is condensed in the primary condenser E103 and then enters the primary vapor-liquid separator V104. The liquid ethanol in V104 enters the reflux tank V106. Meanwhile, the non-condensable gases in V104 enter the secondary condenser E104 for further condensation, and then enter the secondary vapor-liquid separator V105. The liquid ethanol in V105 then enters the ethanol recovery... The non-condensable gases in the ethanol recovery tower reflux tank V106, and the secondary vapor-liquid separator V105 and ethanol recovery tower reflux tank V106, are all sent to the flare system for processing. Liquid ethanol from the ethanol recovery tower reflux tank V106 is sent to the ethanol recovery tower distributor F102 via the ethanol product transfer pump P104. A portion of the liquid ethanol, collected as a product, can either be recycled to the acetal synthesis process outside the boundary without further processing, or it can be cooled and sent to the quench tower as a quenching medium. The remaining liquid ethanol is returned to the upper end of the ethanol recovery tower T103 as reflux liquid. Simultaneously, high-boiling waste liquid is obtained from the bottom of the ethanol recovery tower T103, which is sent to the waste liquid treatment unit for centralized treatment via the first high-boiling waste liquid transfer pump P103.

[0035] In the above technical solution, the specific implementation of step (5) is as follows: the vinyl ethyl ether mixture from the first vinyl ethyl ether purification column T102 is directly fed into the second vinyl ethyl ether purification column T104 for further distillation and purification. The operating pressure of the second vinyl ethyl ether purification column is 0.08 ~ 0.12 MPaA, the reflux ratio is 7 ~ 11, the top temperature is 30.0 ~ 37.0 ℃, and the bottom temperature is 45.0 ~ 50.0 ℃. The overhead gas from the second purification column T104 of the vinyl ethyl ether (VEE) is condensed in the first-stage condenser E105 and then enters the first-stage vapor-liquid separator V107. The liquid VEE in V107 enters the reflux tank V109, while the non-condensable gas enters the second-stage condenser E106 for further condensation, and then is sent to the second-stage vapor-liquid separator V108. The liquid VEE in V108... Alkenyl ethyl ether enters the reflux tank V109 of the second vinyl ethyl ether refining tower. All non-condensable gases in the secondary vapor-liquid separator V108 and the reflux tank V109 of the second vinyl ethyl ether refining tower are sent to the flare system for treatment. Liquid vinyl ethyl ether in the reflux tank V109 is sent to the second vinyl ethyl ether refining tower distributor F103 via the premium vinyl ethyl ether transfer pump P106. A portion of the liquid vinyl ethyl ether is collected as premium vinyl ethyl ether, and the remainder is returned to the upper end of the second vinyl ethyl ether refining tower T104 as reflux liquid. Simultaneously, a small amount of high-boiling impurities are collected from the bottom of the second vinyl ethyl ether refining tower T104 and sent to the waste liquid treatment unit via the second high-boiling waste liquid transfer pump P105.

[0036] The vinyl ethyl ether mixture from the cracking reaction section is first sent to the quench tower T101 in the product refining section. Non-condensable gases such as ethylene are discharged from the top of the tower, and the vinyl ethyl ether liquid mixture after the removal of non-condensable gases is collected from the bottom. This mixture is then sent to the first vinyl ethyl ether refining tower T102 for separation of vinyl ethyl ether from impurities such as ethanol and ethyl acetate. The vinyl ethyl ether mixture is then sent from the top of the tower to the second vinyl ethyl ether refining tower T104 for further distillation. Impurities such as ethyl acetate are collected via a side stream and sent to the boundary area. The ethyl acetate purification unit recovers ethyl acetate; the ethanol mixture from the bottom of the tower is sent to the ethanol recovery tower T103 for ethanol recovery; the ethanol product collected from the top of the ethanol recovery tower T103 can be directly sent to the acetal synthesis process outside the boundary area, or it can be sent to the quench tower as a quench medium after cooling; the high-boiling impurities collected from the bottom of the tower are sent to the waste liquid treatment device for treatment; the vinyl ethyl ether second purification tower T104 collects superior grade vinyl ethyl ether with a purity ≥99% from the top of the tower; the high-boiling impurities collected from the bottom of the tower are sent to the waste liquid treatment device for treatment.The detailed connections of each unit are as follows: the outlet of the gas-phase cracking reactor R101 is connected to the bottom inlet of the quench tower T101; the top gas-phase outlet of the quench tower T101 is connected to the flare system; the liquid-phase outlet of the quench tower T101 bottom is connected to the feed inlet of the first purification tower T102 for vinyl ethyl ether; the first purification tower T102 for vinyl ethyl ether is equipped with a side-stream outlet pipe, which is connected to the ethyl acetate purification unit outside the boundary; the top outlet of the first purification tower T102 for vinyl ethyl ether is connected to the ethylene... The inlet of the first-stage condenser E101 of the vinyl ethyl ether first purification tower is connected to the inlet of the first-stage vapor-liquid separator V101 of the vinyl ethyl ether first purification tower. The vapor outlet of the first-stage vapor-liquid separator V101 of the vinyl ethyl ether first purification tower is connected to the inlet of the second-stage condenser E102 of the vinyl ethyl ether first purification tower. The liquid outlet of the first-stage vapor-liquid separator V101 of the vinyl ethyl ether first purification tower is connected to the inlet of the reflux tank V103 of the vinyl ethyl ether first purification tower. The outlet of the secondary condenser E102 of the first purification column of vinyl ethyl ether is connected to the inlet of the secondary vapor-liquid separator V102 of the first purification column of vinyl ethyl ether. The gas phase outlet of the secondary vapor-liquid separator V102 of the first purification column of vinyl ethyl ether is connected to the flare system. The liquid phase outlet of the secondary vapor-liquid separator V102 of the first purification column of vinyl ethyl ether is connected to the inlet of the reflux tank V103 of the first purification column of vinyl ethyl ether. The gas phase outlet of the reflux tank V103 of the first purification column of vinyl ethyl ether is connected to the flare system. The liquid phase outlet of the reflux tank V103 of the first purification tower is connected to the inlet of the vinyl ethyl ether mixture transfer pump P102. The outlet of the vinyl ethyl ether mixture transfer pump P102 is connected to the inlet of the first vinyl ethyl ether purification tower distributor F101. Under the action of the first vinyl ethyl ether purification tower distributor F101, the vinyl ethyl ether mixture is divided into two streams, which flow into the reflux pipe and the feed pipe of the second vinyl ethyl ether purification tower, respectively. The outlet of the reflux pipe is connected to the upper inlet of the first vinyl ethyl ether purification tower T102.

[0037] The bottom outlet of the first purification column T102 of the vinyl ethyl ether is connected to the inlet of the feed pump P101 of the ethanol recovery column. The outlet of the feed pump P101 of the ethanol recovery column is connected to the inlet of the ethanol recovery column T103. The top outlet of the ethanol recovery column T103 is connected to the inlet of the first-stage condenser E103 of the ethanol recovery column. The outlet of the first-stage condenser E103 of the ethanol recovery column is connected to the inlet of the first-stage vapor-liquid separator V104 of the ethanol recovery column. The vapor phase outlet of the first-stage vapor-liquid separator V104 of the ethanol recovery column is connected to the inlet of the second-stage condenser E104 of the ethanol recovery column. The liquid phase outlet of the first-stage vapor-liquid separator V104 of the ethanol recovery column is connected to the inlet of the reflux tank V106 of the ethanol recovery column. The outlet of the second-stage condenser E104 of the ethanol recovery column is connected to the inlet of the second-stage vapor-liquid separator V105 of the ethanol recovery column. The vapor outlet of separator V105 is connected to the flare system. The liquid outlet of the secondary vapor-liquid separator V105 in the ethanol recovery tower is connected to the inlet of the reflux tank V106 in the ethanol recovery tower. The vapor outlet of the reflux tank V106 is connected to the flare system. The liquid outlet of the reflux tank V106 is connected to the inlet of the ethanol product transfer pump P104. The outlet of the ethanol product transfer pump P104 is connected to the inlet of the ethanol recovery tower distributor F102. Under the action of the ethanol recovery tower distributor F102, the ethanol product is divided into two streams, flowing into the reflux pipeline and the product pipeline respectively. The outlet of the reflux pipeline is connected to the upper inlet of the ethanol recovery tower T103. The ethanol product is collected from the product pipeline. The outlet of the ethanol product pipeline can be connected to the inlet of the acetal synthesis process outside the boundary or to the ethanol cooling device outside the boundary. The bottom outlet of the ethanol recovery tower T103 is connected to the inlet of the first high-boiling waste liquid transfer pump P103. The outlet of the first high-boiling waste liquid transfer pump P103 is connected to the waste liquid treatment device.

[0038] The mixing pipe outlet of the top distributor F101 of the first purification column T102 of vinyl ethyl ether is connected to the feed inlet of the second purification column T104 of vinyl ethyl ether. The top outlet of the second purification column T104 of vinyl ethyl ether is connected to the inlet of the first-stage condenser E105 of the second purification column of vinyl ethyl ether. The outlet of the first-stage condenser E105 of the second purification column of vinyl ethyl ether is connected to the inlet of the first-stage vapor-liquid separator V107 of the second purification column of vinyl ethyl ether. The vapor phase outlet of the first-stage vapor-liquid separator V107 of the second purification column of vinyl ethyl ether is connected to the inlet of the second-stage condenser E106 of the second purification column of vinyl ethyl ether. The liquid phase outlet of the first-stage vapor-liquid separator V107 of the second purification column of vinyl ethyl ether is connected to the inlet of the reflux tank V109 of the second purification column of vinyl ethyl ether. The outlet of the second-stage condenser E106 of the second purification column of vinyl ethyl ether is connected to the inlet of the second-stage vapor-liquid separator V108 of the second purification column of vinyl ethyl ether. The gas phase outlet of the secondary vapor-liquid separator V108 in the second purification tower of vinyl ethyl ether is connected to the flare system. The liquid phase outlet of the secondary vapor-liquid separator V108 in the second purification tower of vinyl ethyl ether is connected to the inlet of the reflux tank V109 in the second purification tower of vinyl ethyl ether. The gas phase outlet of the reflux tank V109 in the second purification tower of vinyl ethyl ether is connected to the flare system. The liquid phase outlet of the reflux tank V109 in the second purification tower of vinyl ethyl ether is connected to the inlet of the premium vinyl ethyl ether transfer pump P106. The outlet of the premium vinyl ethyl ether transfer pump P106 is connected to the inlet of the distributor F103 in the second purification tower of vinyl ethyl ether. The premium vinyl ethyl ether is divided into two streams by the distributor F103 in the second purification tower of vinyl ethyl ether, which flow into the reflux pipeline and the product pipeline respectively. The outlet of the reflux pipeline is connected to the upper inlet of the second purification tower of vinyl ethyl ether T104. The premium vinyl ethyl ether with a purity ≥99% is collected from the product pipeline. The bottom outlet of the second purification tower T104 for vinyl ethyl ether is connected to the inlet of the second high-boiling waste liquid transfer pump P105, and the outlet of the second high-boiling waste liquid transfer pump P105 is connected to the waste liquid treatment device.

[0039] The advantages and beneficial effects of this invention are as follows:

[0040] 1. The present invention relates to a novel process for the production of vinyl ethyl ether, the advantages of which are the invention of a process route adapted to catalytic cracking-separation purification, the use of calcium phosphate as a catalyst and the control of reaction conditions to suppress the generation of by-products; at the same time, the distillation separation sequence and supporting equipment are designed according to the product composition, so as to achieve efficient separation of vinyl ethyl ether from impurities such as ethanol, ethylene, ethyl acetate, and water, so as to obtain a high-grade vinyl ethyl ether with a purity of ≥99%.

[0041] 2. The present invention relates to a novel process for the production of vinyl ethyl ether, the advantage of which is that a scheme is designed to separate vinyl ethyl ether and ethanol without extractant. The present invention designs the parameters of the distillation device based on measured phase equilibrium data, and at the same time, with the help of the separation effect of water by-products of calcium phosphate catalytic cracking forming an azeotrope with ethanol, the separation of vinyl ethyl ether and ethanol is achieved, effectively avoiding the disadvantages of high energy consumption of extractant circulation and large amount of wastewater generation in the extractive distillation route.

[0042] 3. The present invention relates to a novel vinyl ethyl ether production process, the advantage of which is the design of an ethanol recovery system, which sets up an ethanol recovery tower to treat the bottom material of the first purification tower and recover ethanol with a purity of >98%. The ethanol product can be directly reused in the acetal synthesis process, or it can be sent to the quench tower after cooling as a quenching medium to realize the recycling of ethanol, reduce the production cost of acetal and reduce waste liquid discharge.

[0043] 4. This invention relates to a novel process for producing vinyl ethyl ether, which has the advantage of enabling the separation and recovery of ethyl acetate. Ethyl acetate, an oxidation byproduct produced during the condensation of ethanol and acetaldehyde to form acetal, can affect the distillation and purification process of vinyl ethyl ether. This invention addresses this by installing a side-stream sampling pipe above the high-concentration ethyl acetate enrichment tray in the first purification tower of vinyl ethyl ether. The sampled ethyl acetate mixture is then sent to an off-site recovery and purification unit, thus achieving the recovery and utilization of ethyl acetate.

[0044] 5. The present invention relates to a novel vinyl ethyl ether production process, the advantage of which is that the distillation and purification section is equipped with a first vinyl ethyl ether purification tower and a second vinyl ethyl ether purification tower, which can stably produce high-grade vinyl ethyl ether with a purity of ≥99%, which can meet the production requirements of fine chemicals such as sulfadiazine and glutaraldehyde. Attached Figure Description

[0045] Figure 1 This invention presents an experimentally obtained phase diagram of the vinyl ethyl ether-acetal binary system at ambient pressure and temperature, representing its composition.

[0046] Figure 2 This invention relates to a phase diagram of the vinyl ether-ethanol binary system at ambient pressure and temperature, obtained experimentally.

[0047] Figure 3 This invention relates to a phase diagram of the vinyl ether-water binary system at ambient pressure and temperature, obtained experimentally.

[0048] Figure 4 : A schematic diagram of the production process of vinyl ethyl ether of the present invention.

[0049] The components include: gas phase cracking reactor R101, quench tower T101, first-stage condenser of vinyl ethyl ether T102, first-stage condenser of vinyl ethyl ether E101, first-stage vapor-liquid separator of vinyl ethyl ether V101, second-stage condenser of vinyl ethyl ether E102, second-stage vapor-liquid separator of vinyl ethyl ether V102, reflux tank of vinyl ethyl ether V103, feed pump of ethanol recovery tower P101, mixture transfer pump of vinyl ethyl ether P102, distributor of vinyl ethyl ether first-stage condenser F101, ethanol recovery tower T103, first-stage condenser of ethanol recovery tower E103, first-stage vapor-liquid separator of ethanol recovery tower V104, and second-stage condenser of ethanol recovery tower. E104, Secondary vapor-liquid separator of ethanol recovery tower; V105, reflux tank of ethanol recovery tower; V106, First high-boiling waste liquid transfer pump; P103, Ethanol product transfer pump; P104, Diverter of ethanol recovery tower; F102, Secondary purification tower of vinyl ethyl ether; T104, First-stage condenser of vinyl ethyl ether; E105, First-stage vapor-liquid separator of vinyl ethyl ether; V107, Secondary condenser of vinyl ethyl ether; E106, Secondary vapor-liquid separator of vinyl ethyl ether; V108, Secondary vapor-liquid separator of vinyl ethyl ether; V109, reflux tank of vinyl ethyl ether; Secondary high-boiling waste liquid transfer pump; P105, Premium vinyl ethyl ether transfer pump; P106, Diverter of vinyl ethyl ether; F103. Detailed Implementation

[0050] The following is a combination of appendices Figure 4 The present invention will be further described in detail through specific embodiments. The following embodiments are merely descriptive and not limiting, and should not be used to limit the scope of protection of the present invention.

[0051] To achieve the above-mentioned objectives, the technical solution of the present invention is as follows:

[0052] (1) Includes the step of heating acetal and sending it to the gas phase cracking reactor of the cracking reaction section, and generating a mixed product of vinyl ethyl ether and ethanol by calcium phosphate catalytic cracking.

[0053] (2) Includes the steps of sending all the products from the reaction section to the quench tower of the product refining section, rapidly removing non-condensable gas impurities under normal pressure, and rapidly cooling the cracked gas.

[0054] (3) Includes the step of sending the liquid phase mixture at the bottom of the quench tower to the first purification tower of vinyl ethyl ether, separating vinyl ethyl ether and ethanol by distillation, and separating ethyl acetate through a side-stream pipeline.

[0055] (4) Includes the step of sending the ethanol mixture from the bottom of the first vinyl ether refining tower to an ethanol recovery tower to recover and recycle the ethanol;

[0056] (5) Includes the step of sending the vinyl ethyl ether mixture at the top of the first vinyl ethyl ether refining tower to the second vinyl ethyl ether refining tower for further purification to obtain a superior vinyl ethyl ether product;

[0057] This invention provides a novel apparatus for the production of vinyl ethyl ether;

[0058] This includes a gas-phase cracking reactor R101, a quench tower T101, a first-stage condenser for vinyl ethyl ether (DEE) T102, a first-stage condenser for DEE E101, a first-stage vapor-liquid separator for DEE E101, a second-stage condenser for DEE E102, a second-stage vapor-liquid separator for DEE E102, a reflux tank for DEE E103, a feed pump for the ethanol recovery tower P101, a mixture transfer pump for DEE E102, a distributor for DEE E101, an ethanol recovery tower T103, a first-stage condenser for the ethanol recovery tower E103, a first-stage vapor-liquid separator for the ethanol recovery tower V104, and a second-stage condenser for the ethanol recovery tower. E104, Secondary vapor-liquid separator of ethanol recovery tower; V105, reflux tank of ethanol recovery tower; V106, First high-boiling waste liquid transfer pump; P103, Ethanol product transfer pump; P104, Diverter of ethanol recovery tower; F102, Secondary purification tower of vinyl ethyl ether; T104, First-stage condenser of vinyl ethyl ether; E105, First-stage vapor-liquid separator of vinyl ethyl ether; V107, Secondary condenser of vinyl ethyl ether; E106, Secondary vapor-liquid separator of vinyl ethyl ether; V108, Secondary vapor-liquid separator of vinyl ethyl ether; V109, reflux tank of vinyl ethyl ether; Secondary high-boiling waste liquid transfer pump; P105, Premium vinyl ethyl ether transfer pump; P106, Diverter of vinyl ethyl ether; F103.

[0059] In the above technical solution, the specific implementation of step (1) is as follows: the raw material acetal is preheated to the reaction temperature and continuously fed into the isothermal gas-phase cracking reactor R101; the operating pressure of the gas-phase cracking reactor is 0.10 ~ 0.15 MPaA, the reaction temperature is 275.0 ~ 325.0 ℃, and the mass hourly space velocity of acetal is 3 ~ 9 h⁻¹. Under constant temperature and pressure conditions in the reactor, acetal undergoes a cracking reaction under the catalysis of calcium phosphate to generate vinyl ethyl ether and ethanol, ultimately obtaining a mixed reaction product with vinyl ethyl ether and ethanol as the main components.

[0060] In the above technical solution, the specific implementation of step (2) is as follows: the high-temperature mixed reaction product discharged from the outlet of the gas phase cracking reactor R101 is directly fed into the bottom of the quench tower T101; the operating pressure of the quench tower is 0.10 ~ 0.15 MPaA, the quench medium is ethanol, and the cooling rate is controlled at 25 ~ 30 ℃ / s. After vapor-liquid separation, the liquid phase is a mixed liquid phase material of vinyl ethyl ether with light components removed, which is sent to the subsequent distillation section, and the gas is non-condensable gases such as ethylene and acetaldehyde, which are all sent to the flare system for processing.

[0061] In the above technical solution, the specific implementation of step (3) is as follows: the mixed liquid material collected from the bottom of the quench tower T101 is sent to the first purification tower T102 of the vinyl ethyl ether in the product purification section. The operating pressure of the first purification tower of vinyl ethyl ether is 0.07 ~ 0.12 MPaA; the reflux ratio is 15 ~ 25; the top temperature is 30.0 ~ 38.0 ℃; and the bottom temperature is 80.0 ~ 90.0 ℃. The overhead gas from the first purification column T102 of the vinyl ethyl ether (VEE) is condensed in the first-stage condenser E101 and then enters the first-stage vapor-liquid separator V101. The liquid VEE in V101 enters the reflux tank V103. Meanwhile, the non-condensable gas in V101 enters the second-stage condenser E102 for further condensation, and then enters the second-stage vapor-liquid separator V102. The liquid VEE in V102... The non-condensable gases in the first reflux tank V103 of the vinyl ethyl ether refining tower are all sent to the flare system for processing. The liquid vinyl ethyl ether in the first reflux tank V103 is sent to the first ethyl ether refining tower distributor F101 via the vinyl ethyl ether mixture transfer pump P102. Part of the liquid vinyl ethyl ether mixture is sent to the second ethyl ether refining tower, and the remaining liquid mixture is returned to the top of the first ethyl ether refining tower T102 as reflux liquid. At the same time, an ethyl acetate mixture with a mass flow rate of 40.0 ~ 60.0 kg / hr is collected from the side stream of the first ethyl ether refining tower T102 and sent to the ethyl acetate purification unit outside the boundary to obtain high-purity ethyl acetate. The bottom of the tower yields an ethanol mixture rich in ethanol, unreacted acetal, and other high-boiling impurities. All of this material is sent to the ethanol recovery tower T103 for ethanol purification and recovery.

[0062] In the above technical solution, the specific implementation of step (4) is as follows: the ethanol mixture from the bottom of the first refining tower T102 of the vinyl ethyl ether is fed into the ethanol recovery tower T103 for distillation separation via the ethanol recovery tower feed pump P101. The operating pressure of the ethanol recovery tower is 0.08 ~ 0.12 MPaA, the reflux ratio is 4 ~ 8, the top temperature is 75.0 ~ 80.0℃, and the bottom temperature is 95.0 ~ 105.0℃. The overhead gas from ethanol recovery tower T103 is condensed in the primary condenser E103 and then enters the primary vapor-liquid separator V104. The liquid ethanol in V104 enters the reflux tank V106. Meanwhile, the non-condensable gases in V104 enter the secondary condenser E104 for further condensation, and then enter the secondary vapor-liquid separator V105. The liquid ethanol in V105 then enters the ethanol recovery... The non-condensable gases in the ethanol recovery tower reflux tank V106, and the secondary vapor-liquid separator V105 and ethanol recovery tower reflux tank V106, are all sent to the flare system for processing. Liquid ethanol from the ethanol recovery tower reflux tank V106 is sent to the ethanol recovery tower distributor F102 via the ethanol product transfer pump P104. A portion of the liquid ethanol, collected as a product, can either be recycled to the acetal synthesis process outside the boundary without further processing, or it can be cooled and sent to the quench tower as a quenching medium. The remaining liquid ethanol is returned to the upper end of the ethanol recovery tower T103 as reflux liquid. Simultaneously, high-boiling waste liquid is obtained from the bottom of the ethanol recovery tower T103, which is sent to the waste liquid treatment unit for centralized treatment via the first high-boiling waste liquid transfer pump P103.

[0063] In the above technical solution, the specific implementation of step (5) is as follows: the vinyl ethyl ether mixture from the first vinyl ethyl ether purification column T102 is directly fed into the second vinyl ethyl ether purification column T104 for further distillation and purification. The operating pressure of the second vinyl ethyl ether purification column is 0.08 ~ 0.12 MPaA, the reflux ratio is 7 ~ 11, the top temperature is 30.0 ~ 37.0 ℃, and the bottom temperature is 45.0 ~ 50.0 ℃. The overhead gas from the second purification column T104 of the vinyl ethyl ether (VEE) is condensed in the first-stage condenser E105 and then enters the first-stage vapor-liquid separator V107. The liquid VEE in V107 enters the reflux tank V109, while the non-condensable gas enters the second-stage condenser E106 for further condensation, and then is sent to the second-stage vapor-liquid separator V108. The liquid VEE in V108... Alkenyl ethyl ether enters the reflux tank V109 of the second vinyl ethyl ether refining tower. All non-condensable gases in the secondary vapor-liquid separator V108 and the reflux tank V109 of the second vinyl ethyl ether refining tower are sent to the flare system for treatment. Liquid vinyl ethyl ether in the reflux tank V109 is sent to the second vinyl ethyl ether refining tower distributor F103 via the premium vinyl ethyl ether transfer pump P106. A portion of the liquid vinyl ethyl ether is collected as premium vinyl ethyl ether, and the remainder is returned to the upper end of the second vinyl ethyl ether refining tower T104 as reflux liquid. Simultaneously, a small amount of high-boiling impurities are collected from the bottom of the second vinyl ethyl ether refining tower T104 and sent to the waste liquid treatment unit via the second high-boiling waste liquid transfer pump P105.

[0064] The vinyl ethyl ether mixture from the cracking reaction section is first sent to the quench tower T101 in the product refining section. Non-condensable gases such as ethylene are discharged from the top of the tower, and the vinyl ethyl ether liquid mixture after the removal of non-condensable gases is collected from the bottom. This mixture is then sent to the first vinyl ethyl ether refining tower T102 for separation of vinyl ethyl ether from impurities such as ethanol and ethyl acetate. The vinyl ethyl ether mixture is then sent from the top of the tower to the second vinyl ethyl ether refining tower T104 for further distillation. Impurities such as ethyl acetate are collected via a side stream and sent to the boundary area. The ethyl acetate purification unit recovers ethyl acetate; the ethanol mixture from the bottom of the tower is sent to the ethanol recovery tower T103 for ethanol recovery; the ethanol product collected from the top of the ethanol recovery tower T103 can be directly sent to the acetal synthesis process outside the boundary area, or it can be sent to the quench tower as a quench medium after cooling; the high-boiling impurities collected from the bottom of the tower are sent to the waste liquid treatment device for treatment; the vinyl ethyl ether second purification tower T104 collects superior grade vinyl ethyl ether with a purity ≥99% from the top of the tower; the high-boiling impurities collected from the bottom of the tower are sent to the waste liquid treatment device for treatment.The detailed connections of each unit are as follows: the outlet of the gas-phase cracking reactor R101 is connected to the bottom inlet of the quench tower T101; the top gas-phase outlet of the quench tower T101 is connected to the flare system; the liquid-phase outlet of the quench tower T101 bottom is connected to the feed inlet of the first vinyl ethyl ether purification tower T102; the first vinyl ethyl ether purification tower T102 is equipped with a side-stream outlet pipe, which is connected to the ethyl acetate purification unit outside the boundary; the top outlet of the first vinyl ethyl ether purification tower T102 is connected to the ethyl acetate purification unit outside the boundary. The inlet of the first-stage condenser E101 of the vinyl ethyl ether first-stage purification tower is connected to the inlet of the first-stage vapor-liquid separator V101 of the vinyl ethyl ether first-stage purification tower. The vapor phase outlet of the first-stage vapor-liquid separator V101 of the vinyl ethyl ether first-stage purification tower is connected to the inlet of the second-stage condenser E102 of the vinyl ethyl ether first-stage purification tower. The liquid phase outlet of the first-stage vapor-liquid separator V101 of the vinyl ethyl ether first-stage purification tower is connected to the inlet of the reflux tank V103 of the vinyl ethyl ether first-stage purification tower. The outlet of the secondary condenser E102 in the first purification column of vinyl ethyl ether is connected to the inlet of the secondary vapor-liquid separator V102 in the first purification column of vinyl ethyl ether. The gas phase outlet of the secondary vapor-liquid separator V102 in the first purification column of vinyl ethyl ether is connected to the flare system. The liquid phase outlet of the secondary vapor-liquid separator V102 in the first purification column of vinyl ethyl ether is connected to the inlet of the reflux tank V103 in the first purification column of vinyl ethyl ether. The gas phase outlet of the reflux tank V103 in the first purification column of vinyl ethyl ether is connected to the flare system. The liquid phase outlet of the reflux tank V103 of the first ether refining tower is connected to the inlet of the vinyl ethyl ether mixture transfer pump P102. The outlet of the vinyl ethyl ether mixture transfer pump P102 is connected to the inlet of the splitter F101 of the first vinyl ethyl ether refining tower. Under the action of the splitter F101 of the first vinyl ethyl ether refining tower, the vinyl ethyl ether mixture is divided into two streams, which flow into the reflux pipe and the feed pipe of the second vinyl ethyl ether refining tower, respectively. The reflux pipe is connected to the upper inlet of the first vinyl ethyl ether refining tower T102.

[0065] The bottom outlet of the first purification column T102 of the vinyl ethyl ether is connected to the inlet of the feed pump P101 of the ethanol recovery column. The outlet of the feed pump P101 of the ethanol recovery column is connected to the inlet of the ethanol recovery column T103. The top outlet of the ethanol recovery column T103 is connected to the inlet of the first-stage condenser E103 of the ethanol recovery column. The outlet of the first-stage condenser E103 of the ethanol recovery column is connected to the inlet of the first-stage vapor-liquid separator V104 of the ethanol recovery column. The vapor phase outlet of the first-stage vapor-liquid separator V104 of the ethanol recovery column is connected to the inlet of the second-stage condenser E104 of the ethanol recovery column. The liquid phase outlet of the first-stage vapor-liquid separator V104 of the ethanol recovery column is connected to the inlet of the reflux tank V106 of the ethanol recovery column. The outlet of the second-stage condenser E104 of the ethanol recovery column is connected to the inlet of the second-stage vapor-liquid separator V105 of the ethanol recovery column. The vapor outlet of separator V105 is connected to the flare system. The liquid outlet of the secondary vapor-liquid separator V105 in the ethanol recovery tower is connected to the inlet of the reflux tank V106 in the ethanol recovery tower. The vapor outlet of the reflux tank V106 is connected to the flare system. The liquid outlet of the reflux tank V106 is connected to the inlet of the ethanol product transfer pump P104. The outlet of the ethanol product transfer pump P104 is connected to the inlet of the ethanol recovery tower distributor F102. Under the action of the ethanol recovery tower distributor F102, the ethanol product is divided into two streams, flowing into the reflux pipeline and the product pipeline respectively. The outlet of the reflux pipeline is connected to the upper inlet of the ethanol recovery tower T103. The ethanol product is collected from the product pipeline. The outlet of the ethanol product pipeline can be connected to the inlet of the acetal synthesis process outside the boundary or to the ethanol cooling device outside the boundary. The bottom outlet of the ethanol recovery tower T103 is connected to the inlet of the first high-boiling waste liquid transfer pump P103. The outlet of the first high-boiling waste liquid transfer pump P103 is connected to the waste liquid treatment device.

[0066] The mixing pipe outlet of the top distributor F101 of the first purification column T102 of vinyl ethyl ether is connected to the feed inlet of the second purification column T104 of vinyl ethyl ether. The top outlet of the second purification column T104 of vinyl ethyl ether is connected to the inlet of the first-stage condenser E105 of the second purification column of vinyl ethyl ether. The outlet of the first-stage condenser E105 of the second purification column of vinyl ethyl ether is connected to the inlet of the first-stage vapor-liquid separator V107 of the second purification column of vinyl ethyl ether. The vapor phase outlet of the first-stage vapor-liquid separator V107 of the second purification column of vinyl ethyl ether is connected to the inlet of the second-stage condenser E106 of the second purification column of vinyl ethyl ether. The liquid phase outlet of the first-stage vapor-liquid separator V107 of the second purification column of vinyl ethyl ether is connected to the inlet of the reflux tank V109 of the second purification column of vinyl ethyl ether. The outlet of the second-stage condenser E106 of the second purification column of vinyl ethyl ether is connected to the inlet of the second-stage vapor-liquid separator V108 of the second purification column of vinyl ethyl ether. The gas phase outlet of the secondary vapor-liquid separator V108 in the second purification tower of vinyl ethyl ether is connected to the flare system. The liquid phase outlet of the secondary vapor-liquid separator V108 in the second purification tower of vinyl ethyl ether is connected to the inlet of the reflux tank V109 in the second purification tower of vinyl ethyl ether. The gas phase outlet of the reflux tank V109 in the second purification tower of vinyl ethyl ether is connected to the flare system. The liquid phase outlet of the reflux tank V109 in the second purification tower of vinyl ethyl ether is connected to the inlet of the premium vinyl ethyl ether transfer pump P106. The outlet of the premium vinyl ethyl ether transfer pump P106 is connected to the inlet of the distributor F103 in the second purification tower of vinyl ethyl ether. The premium vinyl ethyl ether is divided into two streams by the distributor F103 in the second purification tower of vinyl ethyl ether, which flow into the reflux pipeline and the product pipeline respectively. The outlet of the reflux pipeline is connected to the upper inlet of the second purification tower of vinyl ethyl ether T104. The premium vinyl ethyl ether with a purity ≥99% is collected from the product pipeline. The bottom outlet of the second purification tower T104 for vinyl ethyl ether is connected to the inlet of the second high-boiling waste liquid transfer pump P105, and the outlet of the second high-boiling waste liquid transfer pump P105 is connected to the waste liquid treatment device.

[0067] The operating pressure of the gas-phase cracking reactor is 0.10 ~ 0.15 MPaA; the reaction temperature is 275.0 ~ 325.0 ℃; the acetal mass hourly space velocity is 3 ~ 9 h⁻¹; the operating pressure of the quench tower is 0.10 ~ 0.15 MPaA, the quench medium is ethanol, and the cooling rate is controlled at 25 ~ 30 ℃ / s; the operating pressure of the first purification tower for vinyl ethyl ether is 0.07 ~ 0.12 MPaA; the reflux ratio is 15 ~ 25; the top temperature is 30.0 ~ 38.0 ℃; the bottom temperature is 80.0 ~ 90.0 ℃; the side-collection mass flow rate of the first purification tower for vinyl ethyl ether is 40.0 ~ 60.0 kg / hr; the operating pressure of the ethanol recovery tower is 0.08 ~ 0.12 MPaA; the reflux ratio is 4 ~ 8; and the top temperature is 75.0 ~ 80.0 ℃. ℃; the bottom temperature of the column is 95.0 ~ 105.0 ℃; the operating pressure of the second purification column of vinyl ethyl ether is 0.08 ~ 0.12 MPaA; the reflux ratio is 7 ~ 11; the top temperature of the column is 30.0 ~ 37.0 ℃; the bottom temperature of the column is 45.0 ~ 50.0 ℃.

[0068] The following specific examples illustrate the implementation process of the method in this application.

[0069] Example 1:

[0070] After preheating the raw material acetal to 325.0℃, it is continuously fed into an isothermal gas-phase cracking reactor R101 packed with calcium phosphate catalyst. The reaction temperature is controlled at 325.0℃, the operating pressure at 0.10 MPaA, and the acetal mass hourly space velocity at 9 h⁻¹ to carry out the catalytic cracking reaction, which converts acetal into vinyl ethyl ether and ethanol. Impurities such as ethylene, acetaldehyde, water, acetic acid, and ethyl acetate are also present, resulting in a mixed cracking product mainly composed of vinyl ethyl ether and ethanol.

[0071] The high-temperature mixed product from the outlet of the gas phase pyrolysis reactor R101 is directly sent to the bottom inlet of the quench tower T101, which operates at an pressure of 0.12 MPaA and a cooling rate of 25℃ / s. Gas-liquid separation is carried out under the action of ethanol. Non-condensable gases such as ethylene and acetaldehyde are separated from the top of the tower. The non-condensable gases are directly sent to the flare system for processing. The mixed liquid phase material of vinyl ethyl ether after the removal of light components is continuously collected from the bottom of the quench tower T101 and sent to the subsequent vinyl ethyl ether purification system.

[0072] The mixed liquid material from the bottom of the quench tower T101 is continuously fed to the first purification tower T102 of vinyl ethyl ether, which operates at a pressure of 0.12 MPaA. The reflux ratio is controlled at 15, the top temperature at 30.0℃, and the bottom temperature at 90.0℃ to separate vinyl ethyl ether from high-boiling impurities such as ethanol. The top gas from the first purification tower T102 of vinyl ethyl ether undergoes multi-stage condensation and vapor-liquid separation before entering the reflux tank V103 of the first purification tower of vinyl ethyl ether. The reflux liquid in the tank is sent to the distributor F101 by the vinyl ethyl ether mixture transfer pump P102. At the same time, a side stream is collected to obtain an ethyl acetate mixture with a mass flow rate of 40.0 kg / hr, which is sent to the ethyl acetate purification unit outside the boundary to obtain high-purity ethyl acetate. The bottom of the tower yields a mixture rich in ethanol and acetal.

[0073] The ethanol mixture collected from the bottom of the first vinyl ethyl ether refining tower T102 is fed into the ethanol recovery tower at an operating pressure of 0.08 MPaA via the ethanol recovery tower feed pump P101. The reflux ratio is controlled at 8, the top temperature at 75.0℃, and the bottom temperature at 105.0℃ to separate ethanol from high-boiling impurities. The overhead gas from the ethanol recovery tower T103, after multi-stage condensation and vapor-liquid separation, enters the ethanol recovery tower reflux tank V106. The reflux liquid in the tank is sent to the distributor F102 via the ethanol product transfer pump P104. By adjusting the reflux and collection ratio through the distributor F102, 98.14% pure ethanol product can be collected from the product pipeline of the ethanol recovery tower T103. This product can be directly sent to the off-site acetal synthesis process or cooled and sent to the quench tower as a quenching medium. The high-boiling waste liquid collected from the bottom of the tower is sent to the waste liquid treatment unit via the first high-boiling waste liquid transfer pump P103.

[0074] The vinyl ethyl ether mixture collected from the top of the first vinyl ethyl ether refining column T102 is fed into the second vinyl ethyl ether refining column T104, operating at a pressure of 0.12 MPaA, for further distillation and purification. The reflux ratio is controlled at 7, the top temperature at 37.0℃, and the bottom temperature at 50.0℃ to achieve deep purification of the vinyl ethyl ether. The top gas from the second vinyl ethyl ether refining column T104, after multi-stage condensation and vapor-liquid separation, enters the second vinyl ethyl ether refining column reflux tank V109. The reflux liquid in the tank is sent to the distributor F103 via the vinyl ethyl ether premium product transfer pump P106. The reflux and product ratio are adjusted by the distributor F103 to obtain a vinyl ethyl ether premium product with a purity of 99.26%. A small amount of high-boiling waste liquid collected from the bottom of the column is sent to the waste liquid treatment unit via the second high-boiling waste liquid transfer pump P105.

[0075] Example 2:

[0076] After preheating the raw material acetal to 300.0℃, it is continuously fed into an isothermal gas-phase cracking reactor R101 packed with calcium phosphate catalyst. The reaction temperature is controlled at 300.0℃, the operating pressure at 0.10 MPaA, and the acetal mass hourly space velocity at 6 h⁻¹ to carry out the catalytic cracking reaction, which converts acetal into vinyl ethyl ether and ethanol. Impurities such as ethylene, acetaldehyde, water, acetic acid, and ethyl acetate are also present, resulting in a mixed cracking product mainly composed of vinyl ethyl ether and ethanol.

[0077] The high-temperature mixed product from the outlet of the gas phase pyrolysis reactor R101 is directly sent to the bottom inlet of the quench tower T101, which operates at an pressure of 0.10 MPaA and a cooling rate of 29℃ / s. Under the action of ethanol, vapor-liquid separation is carried out. Non-condensable gases such as ethylene and acetaldehyde are separated from the top of the tower. The non-condensable gases are directly sent to the flare system for processing. The mixed liquid phase material of vinyl ethyl ether after the removal of light components is continuously collected from the bottom of the quench tower T101 and sent to the subsequent vinyl ethyl ether purification system.

[0078] The mixed liquid material from the bottom of the quench tower T101 is continuously fed to the first purification tower T102 of vinyl ethyl ether, which operates at an pressure of 0.10 MPaA. The reflux ratio is controlled at 20, the top temperature at 34.9℃, and the bottom temperature at 84.6℃ to separate vinyl ethyl ether from high-boiling impurities such as ethanol. The overhead gas from the first purification tower T102, after multi-stage condensation and vapor-liquid separation, enters the reflux tank V103. The reflux liquid in the tank is sent to the distributor F101 via the vinyl ethyl ether mixture transfer pump P102. Simultaneously, a side stream is collected to obtain an ethyl acetate mixture with a mass flow rate of 50.0 kg / hr, which is sent to an off-site ethyl acetate purification unit to obtain high-purity ethyl acetate. The bottom of the tower yields a mixture rich in ethanol and acetal.

[0079] The ethanol mixture collected from the bottom of the first vinyl ethyl ether refining tower T102 is fed into the ethanol recovery tower at an operating pressure of 0.10 MPaA via the ethanol recovery tower feed pump P101. The reflux ratio is controlled at 6.3, the top temperature at 77.7℃, and the bottom temperature at 102.5℃ to separate ethanol from high-boiling impurities. The overhead gas from the ethanol recovery tower T103, after multi-stage condensation and vapor-liquid separation, enters the ethanol recovery tower reflux tank V106. The reflux liquid in the tank is sent to the distributor F102 via the ethanol product transfer pump P104. By adjusting the reflux and collection ratio through the distributor F102, 98.29% pure ethanol product can be collected from the product pipeline of the ethanol recovery tower T103. This product can be directly sent to the off-site acetal synthesis process or cooled and sent to the quench tower as a quenching medium. The high-boiling waste liquid collected from the bottom of the tower is sent to the waste liquid treatment unit via the first high-boiling waste liquid transfer pump P103.

[0080] The vinyl ethyl ether mixture collected from the top of the first vinyl ethyl ether refining column T102 is fed into the second vinyl ethyl ether refining column T104, operating at an pressure of 0.10 MPaA, for further distillation and purification. The reflux ratio is controlled at 8.7, the top temperature at 34.6℃, and the bottom temperature at 47.3℃ to achieve deep purification of vinyl ethyl ether. The top gas from the second vinyl ethyl ether refining column T104, after multi-stage condensation and vapor-liquid separation, enters the reflux tank V109. The reflux liquid in the tank is sent to the distributor F103 via the vinyl ethyl ether premium product transfer pump P106. By adjusting the reflux and product ratio through the distributor F103, 99.61% pure vinyl ethyl ether premium product can be collected from the product pipeline of the second vinyl ethyl ether refining column T104. A small amount of high-boiling waste liquid collected from the bottom of the column is sent to the waste liquid treatment unit via the second high-boiling waste liquid transfer pump P105.

[0081] Example 3:

[0082] After preheating the raw material acetal to 275.0℃, it is continuously fed into an isothermal gas-phase cracking reactor R101 packed with calcium phosphate catalyst. The reaction temperature is controlled at 275.0℃, the operating pressure at 0.15 MPaA, and the acetal mass hourly space velocity at 3 h⁻¹ to carry out the catalytic cracking reaction, which converts acetal into vinyl ethyl ether and ethanol. Impurities such as ethylene, acetaldehyde, water, acetic acid, and ethyl acetate are also present, resulting in a mixed cracking product mainly composed of vinyl ethyl ether and ethanol.

[0083] The high-temperature mixed product from the outlet of the gas phase pyrolysis reactor R101 is directly sent to the bottom inlet of the quench tower T101, which operates at an pressure of 0.15 MPaA and a cooling rate of 30℃ / s. Under the action of ethanol, vapor-liquid separation is carried out. Non-condensable gases such as ethylene and acetaldehyde are separated from the top of the tower. The non-condensable gases are directly sent to the flare system for processing. The mixed liquid phase material of vinyl ethyl ether after the removal of light components is continuously collected from the bottom of the quench tower T101 and sent to the subsequent vinyl ethyl ether purification system.

[0084] The mixed liquid material from the bottom of the quench tower T101 is continuously fed to the first purification tower T102 of vinyl ethyl ether, which operates at an pressure of 0.07 MPaA. The reflux ratio is controlled at 25, the top temperature at 38.0℃, and the bottom temperature at 80.0℃ to separate vinyl ethyl ether from high-boiling impurities such as ethanol. The top gas from the first purification tower T102 enters the reflux tank V103 of the first purification tower of vinyl ethyl ether after multi-stage condensation and vapor-liquid separation. The reflux liquid in the tank is sent to the distributor F101 by the vinyl ethyl ether mixture transfer pump P102. At the same time, a side stream is collected to obtain an ethyl acetate mixture with a mass flow rate of 60.0 kg / hr, which is sent to the ethyl acetate purification unit outside the boundary to obtain high-purity ethyl acetate. The bottom of the tower yields a mixture rich in ethanol and acetal.

[0085] The ethanol mixture collected from the bottom of the first refining tower T102 of the vinyl ethyl ether refining tower is fed into the ethanol recovery tower at an operating pressure of 0.12 MPaA via the ethanol recovery tower feed pump P101. The reflux ratio is controlled at 4, the top temperature at 80.0℃, and the bottom temperature at 95.0℃ to separate ethanol and high-boiling impurities. The top gas from the ethanol recovery tower T103, after multi-stage condensation and vapor-liquid separation, enters the ethanol recovery tower reflux tank V106. The reflux liquid in the tank is sent to the distributor F102 via the ethanol product transfer pump P104. By adjusting the reflux and collection ratio through the distributor F102, ethanol product with a purity of 98.12% can be collected from the product pipeline of the ethanol recovery tower T103. This product can be directly sent to the acetal synthesis process outside the boundary, or it can be cooled and sent to the quench tower as a quenching medium. The high-boiling waste liquid collected from the bottom of the tower is sent to the waste liquid treatment unit via the first high-boiling waste liquid transfer pump P103.

[0086] The vinyl ethyl ether mixture collected from the top of the first vinyl ethyl ether refining column T102 is fed into the second vinyl ethyl ether refining column T104, operating at an pressure of 0.08 MPaA, for further distillation and purification. The reflux ratio is controlled at 1:1, the top temperature at 30.0℃, and the bottom temperature at 45.0℃ to achieve deep purification of vinyl ethyl ether. The top gas from the second vinyl ethyl ether refining column T104, after multi-stage condensation and vapor-liquid separation, enters the reflux tank V109 of the second vinyl ethyl ether refining column. The reflux liquid in the tank is sent to the distributor F103 via the superior vinyl ethyl ether transfer pump P106. By adjusting the reflux and collection ratio through the distributor F103, a superior vinyl ethyl ether product with a purity of 99.26% is obtained. A small amount of high-boiling waste liquid collected from the bottom of the column is sent to the waste liquid treatment unit via the second high-boiling waste liquid transfer pump P105.

Claims

1. A process for producing vinyl ethyl ether by acetal cracking, characterized in that, Includes the following steps: (1) Includes the step of heating acetal to the reaction temperature and continuously feeding it into the reactor, and cracking it under the catalysis of calcium phosphate to generate a mixed product of vinyl ethyl ether and ethanol; (2) Includes the steps of sending all the products from the reaction section to the quench tower of the refining section, rapidly removing non-condensable gas impurities under normal pressure, and rapidly cooling the cracked gas. (3) Includes the step of sending the liquid phase mixture from the bottom of the quench tower to the first purification tower for vinyl ethyl ether, separating vinyl ethyl ether and ethanol by distillation, and separating ethyl acetate through a side-stream pipeline; (4) Includes the step of sending the ethanol mixture from the bottom of the first vinyl ether refining tower to an ethanol recovery tower to recover and recycle the ethanol; (5) Includes the step of sending the vinyl ethyl ether mixture at the top of the first vinyl ethyl ether purification tower to the second vinyl ethyl ether purification tower for further purification to obtain a superior vinyl ethyl ether product.

2. The process for producing vinyl ethyl ether by acetal cracking as described in claim 1, characterized in that: Step (1) is as follows: the raw material acetal is preheated to the reaction temperature and continuously fed into an isothermal gas-phase cracking reactor; the operating pressure of the gas-phase cracking reactor is 0.10 ~ 0.15 MPaA, the reaction temperature is 275.0 ~ 325.0 ℃, and the mass hourly space velocity of acetal is 3 ~ 9 h⁻¹; acetal undergoes cracking reaction under the catalysis of calcium phosphate to generate vinyl ethyl ether and ethanol, and finally a mixed reaction product with vinyl ethyl ether and ethanol as the main components is obtained.

3. The process for producing vinyl ethyl ether by acetal cracking as described in claim 1, characterized in that: Step (2) is as follows: the high-temperature mixed reaction products discharged from the outlet of the gas phase cracking reactor are directly fed into the bottom of the quench tower; the operating pressure of the quench tower is 0.10 ~ 0.15 MPaA, the quench medium is ethanol, and the cooling rate is controlled at 25 ~ 30 ℃ / s; after vapor-liquid separation, the liquid phase after rapid cooling is a mixture of vinyl ether with light components removed, which is sent to the subsequent distillation section, and the gas is non-condensable gas such as ethylene and acetaldehyde, which is sent to the flare system for processing.

4. The process for producing vinyl ethyl ether by acetal cracking as described in claim 1, characterized in that: Step (3) involves feeding the mixed liquid material collected from the bottom of the quench tower into the first refining tower of vinyl ethyl ether in the product refining section. The operating pressure of the first refining tower is 0.07 ~ 0.12 MPaA, the reflux ratio is 15 ~ 25, the top temperature is 30.0 ~ 38.0 ℃, and the bottom temperature is 80.0 ~ 90.0 ℃. At ℃; the overhead gas from the first purification tower of vinyl ethyl ether is condensed by a multi-stage condenser, and the liquid vinyl ethyl ether is sent to the reflux tank of the first purification tower of vinyl ethyl ether. All non-condensable gases are sent to the flare system for treatment. The liquid vinyl ethyl ether in the reflux tank of the first purification tower of vinyl ethyl ether is sent to the distributor of the first purification tower of vinyl ethyl ether by a vinyl ethyl ether mixture transfer pump. Part of the liquid vinyl ethyl ether mixture is sent to the second purification tower of vinyl ethyl ether, and the remaining liquid mixture is returned to the top of the first purification tower of vinyl ethyl ether as reflux liquid. At the same time, the side stream of the first purification tower of vinyl ethyl ether produces a mixture of ethyl acetate with a mass flow rate of 40.0 ~ 60.0 kg / hr, which is sent to the ethyl acetate purification unit outside the boundary to obtain high-purity ethyl acetate. The bottom of the tower yields a mixture of ethanol rich in ethanol, unreacted acetal, and other high-boiling impurities. All of this material is sent to the ethanol recovery tower for ethanol purification and recovery.

5. The process for producing vinyl ethyl ether by acetal cracking as described in claim 1, characterized in that: Step (4) involves the following: the ethanol mixture from the bottom of the first vinyl ethyl ether refining column is fed into the ethanol recovery column via the ethanol recovery column feed pump for distillation separation; the operating pressure of the ethanol recovery column is 0.08 ~ 0.12 MPaA, the reflux ratio is 4 ~ 8, the top temperature is 75.0 ~ 80.0 ℃, and the bottom temperature is 95.0 ~ 105.0 ℃. ℃; After the overhead gas of the ethanol recovery tower is condensed by a multi-stage condenser, the liquid ethanol is sent to the ethanol recovery tower reflux tank, and all other non-condensable gases are sent to the flare system for treatment. The liquid ethanol in the ethanol recovery tower reflux tank is sent to the ethanol recovery tower distributor by the ethanol product transfer pump. Part of the ethanol is collected as a product and can be sent to the acetal synthesis process outside the boundary for recycling without additional treatment, or it can be cooled and sent to the quench tower as a quench medium; the remaining part of the ethanol is returned to the top of the ethanol recovery tower as reflux liquid; at the same time, the bottom of the ethanol recovery tower produces high-boiling waste liquid, which is sent to the waste liquid treatment device for centralized treatment by the first high-boiling waste liquid transfer pump.

6. The process for producing vinyl ethyl ether by acetal cracking as described in claim 1, characterized in that: Step (5) involves feeding the vinyl ethyl ether mixture from the product pipeline of the first vinyl ethyl ether refining column directly into the second vinyl ethyl ether refining column for further distillation and purification. The operating pressure of the second vinyl ethyl ether refining column is 0.08 ~ 0.12 MPaA, the reflux ratio is 7 ~ 11, the top temperature is 30.0 ~ 37.0 ℃, and the bottom temperature is 45.0 ~ 50.0 ℃. At ℃; the overhead gas from the second purification tower of vinyl ethyl ether is condensed by a multi-stage condenser, and the liquid vinyl ethyl ether is sent to the reflux tank of the second purification tower of vinyl ethyl ether. All other non-condensable gases are sent to the flare system for treatment. The liquid vinyl ethyl ether in the reflux tank of the second purification tower of vinyl ethyl ether is sent to the distributor of the second purification tower of vinyl ethyl ether via a premium vinyl ethyl ether transfer pump. Part of the liquid vinyl ethyl ether is collected as premium vinyl ethyl ether, and the rest is returned to the top of the second purification tower of vinyl ethyl ether as reflux liquid. At the same time, a small amount of high-boiling impurities are collected from the bottom of the second purification tower of vinyl ethyl ether and sent to the waste liquid treatment device via a second high-boiling waste liquid transfer pump.

7. An apparatus for producing vinyl ethyl ether by cracking acetal as claimed in claim 1, characterized in that, The system includes a gas-phase cracking reactor (R101), a quench tower (T101), a first vinyl ethyl ether purification tower (T102), an ethanol recovery tower (T103), and a second vinyl ethyl ether purification tower (T104). The outlet of the gas-phase cracking reactor (R101) is connected to the bottom inlet of the quench tower (T101), the top outlet of the quench tower (T101) is connected to a flare system, and the bottom outlet of the quench tower (T101) is connected to the inlet of the first vinyl ethyl ether purification tower (T102). The first vinyl ethyl ether purification tower (T102) is equipped with a side-stream extraction pipeline, which connects to an ethyl acetate purification unit outside the boundary area. The top of the first vinyl ethyl ether purification tower (T102) is connected to the first vinyl ethyl ether purification unit. The inlet of the refining tower splitter (F101) is connected to both the upper inlet of the first vinyl ethyl ether refining tower (T102) and the feed inlet of the second vinyl ethyl ether refining tower (T104). The bottom outlet of the first refining tower (T102) is connected to the feed inlet of the ethanol recovery tower (T103). An ethanol product pipeline is installed at the top of the ethanol recovery tower (T103), which connects to the acetal synthesis process outside the boundary area. The bottom outlet of the ethanol recovery tower (T103) is connected to a waste liquid treatment device. A superior vinyl ethyl ether product pipeline is installed at the top of the second vinyl ethyl ether refining tower (T104), and the bottom outlet of the second vinyl ethyl ether refining tower (T104) is connected to a waste liquid treatment device.

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