A continuous distillation process and equipment for bromoalkanes

Abstract

The present invention belongs to the field of medicine, and discloses a continuous distillation process and equipment for bromoalkanes. A continuous distillation equipment for bromoalkanes comprises an extraction device and a distillation device, wherein the extraction device comprises a hydrobromic acid extraction tower, a water washing extraction tower, and an alkali washing extraction tower; the distillation device is a double-tower distillation device, comprising a light removal tower and a refining tower; or the distillation device is a single-tower separation device, comprising a refining tower. The present invention also discloses a continuous distillation process for bromoalkanes, comprising: three-stage extraction and refining to obtain a bromoalkanes product. (1) Compared with the traditional process, the bromoalkanes distillation process of the present invention adopts a combined process of three-stage extraction and two-stage refining to recover alcohol substances, has a large processing capacity, and the purity of the bromoalkanes product can reach the pharmaceutical field, and the product yield is higher. The present invention adopts extraction standing oil-water separation and azeotropic light removal to effectively remove moisture from the bromoalkanes, without the need for further drying, and the system does not generate solid waste.

Description

Technical Field

[0001] The invention belongs to the field of medicine, specifically to the fields of medicine synthesis, refrigerants, industrial solvents, insecticides, bactericides, etc., and relates to a high-purity brominated alkane continuous distillation process and equipment. Background Art

[0002] Bromoalkanes are widely used in organic synthesis, pharmaceutical synthesis, pesticides, fungicides, etc. The traditional process for preparing bromoalkanes has low product purity due to the azeotropic problem between raw materials and products (Table 1). They can only be used in the fields of pesticides and insecticides. Their purity is far from meeting the standards of the pharmaceutical industry. It is urgent to develop a high-purity bromoalkanes distillation process.

[0003] Chinese patent CN 113385099 A purifies the crude brominated alkane product twice by reactive distillation and secondary distillation. Since the conversion rate of raw material alcohols in the synthesis process of brominated alkane cannot reach 100%, the raw material alcohols will azeotropize with water and / or brominated alkane, thereby affecting the purity of the brominated alkane. Although it is purified by secondary distillation, the yield of high-purity brominated alkane is low, generally around 90%.

[0004] Table 1. Azeotropic compositions of bromoalkanes

[0005] Summary of the invention

[0006] The invention aims to solve the problems of low product purity, high energy consumption, low production capacity and low yield of existing brominated alkane synthesis processes, and to provide a new high-purity brominated alkane continuous distillation process and equipment. The process is simple to operate, has low energy consumption and high production capacity, and the prepared brominated alkane products have high purity and high yield, and no waste water or waste solid is generated.

[0007] The objectives of the present invention are achieved through the following technical solutions.

[0008] A high-purity brominated alkane continuous distillation device, comprising an extraction device and a distillation device;

[0009] The extraction device comprises a hydrobromic acid extraction tower 1, a water-washing extraction tower 3, and an alkali-washing extraction tower 12; the hydrobromic acid extraction tower 1 is provided with a high-density material inlet at the top, a low-density material inlet at the bottom, a high-density material outlet at the bottom, and a low-density material outlet at the top, wherein the low-density material outlet is higher than the high-density material inlet, and the high-density material outlet is lower than the low-density material inlet; the low-density material outlet or the high-density material outlet of the hydrobromic acid extraction tower 1 is connected to the brominated alkane inlet at the top of the water-washing extraction tower 3 to transport the brominated alkane after extraction and stratification to the water-washing extraction tower 3; The water washing extraction tower 3 is provided with a water inlet at the bottom, a brominated alkane outlet at the bottom, and a water outlet at the top. The brominated alkane inlet is lower than the water outlet, and the brominated alkane outlet is lower than the water inlet; the brominated alkane outlet of the water washing extraction tower 3 is connected to the brominated alkane inlet at the top of the alkali washing extraction tower 12; the alkali washing extraction tower 12 is provided with an alkali solution inlet at the bottom, a brominated alkane outlet at the bottom, and a salt solution outlet and a gas outlet at the top, respectively. The brominated alkane inlet is lower than the salt solution outlet, and the brominated alkane outlet is lower than the alkali solution inlet; the brominated alkane outlet of the alkali washing extraction tower 12 is connected to the inlet of the rectification device;

[0010] The distillation device is a double-tower distillation equipment, including a light-removal tower 15 and a refining tower 21; the inlet of the light-removal tower 15 is connected to the brominated alkane outlet at the bottom of the alkali washing extraction tower 12, the light-removal tower 15 is equipped with a light-removal tower reboiler 19, the gas phase outlet at the top of the light-removal tower 15 is connected to the air inlet of the light-removal tower condenser 16, the liquid outlet of the light-removal tower condenser 16 is connected to the inlet of the light-removal tower reflux tank 17, and the outlet of the light-removal tower reflux tank 17 is respectively connected to the reflux port at the top of the light-removal tower 15 and the water inlet of the water washing extraction tower 3. The bottom outlet of the light removal tower 15 is connected to the inlet of the middle part of the refining tower 21; the refining tower 21 is equipped with a refining tower reboiler 26, the gas phase outlet at the top of the refining tower 21 is connected to the air inlet of the refining tower condenser 22, the liquid outlet of the refining tower condenser 22 is connected to the inlet of the refining tower reflux tank 23, the outlet of the refining tower reflux tank 23 is respectively connected to the reflux port at the top of the refining tower 21 and the inlet of the product cooler 25, and the brominated alkane product is extracted at the outlet of the product condenser 25;

[0011] Or the distillation device is a single-tower separation device, including a refining tower 21; the lower inlet of the refining tower 21 is connected to the brominated alkane outlet at the bottom of the alkali washing extraction tower 12, the refining tower 21 is equipped with a refining tower reboiler 26, the gas phase outlet at the top of the refining tower 21 is connected to the air inlet of the refining tower condenser 22, the liquid outlet of the refining tower condenser 22 is connected to the inlet of the refining tower reflux tank 23, and the outlet of the refining tower reflux tank 23 is respectively connected to the reflux port at the top of the refining tower 21 and the water inlet of the water washing extraction tower 3; the middle discharge port of the refining tower 21 is connected to the inlet of the product condenser 25, and the brominated alkane product is extracted at the outlet of the product condenser 25.

[0012] Preferably, when the density of hydrobromic acid is higher than that of brominated alkanes, hydrobromic acid is introduced from the upper high-density material inlet of the hydrobromic acid extraction tower 1 to extract alcohol substances in the brominated alkanes reaction liquid, and the brominated alkanes reaction liquid is introduced from the lower low-density material inlet, and the hydrobromic acid after extraction and stratification is discharged from the bottom high-density material outlet, and the brominated alkanes after extraction and stratification are discharged from the top low-density material outlet.

[0013] When the density of hydrobromic acid is lower than that of bromoalkanes, the bromoalkanes reaction liquid is introduced from the high-density material inlet at the top of the hydrobromic acid extraction tower 1, and the hydrobromic acid is introduced from the low-density material inlet at the bottom to extract the alcohol substances in the bromoalkanes reaction liquid. The hydrobromic acid after extraction and stratification is discharged from the top low-density material outlet, and the bromoalkanes after extraction and stratification are discharged from the bottom high-density material outlet.

[0014] Preferably, in the hydrobromic acid extraction tower 1, the low-density material outlet is 0.2 to 3 m higher than the high-density material inlet, preferably 0.5 to 1.5 m, and the high-density material outlet is 0.2 to 3 m lower than the low-density material inlet, preferably 0.5 to 1.5 m.

[0015] Preferably, in the water-wash extraction tower 3, the inlet of the brominated alkane is 0.2 to 4 m lower than the water outlet, preferably 0.5 to 2 m, and the outlet of the brominated alkane is 0.2 to 4 m lower than the water inlet, preferably 0.5 to 2 m.

[0016] Preferably, in the alkali washing extraction tower 12, the inlet of the brominated alkane is 0.2 to 3.5 m lower than the outlet of the salt solution, preferably 0.5 to 2 m, and the outlet of the brominated alkane is 0.2 to 3.5 m lower than the inlet of the alkali solution, preferably 0.5 to 2 m.

[0017] Preferably, the low-density material outlet or the high-density material outlet of the hydrobromic acid extraction tower 1 is connected to the brominated alkane inlet at the top of the water-washing extraction tower 3 via a delivery pump 1 2 to deliver the brominated alkane after extraction and stratification to the water-washing extraction tower 3; the brominated alkane outlet at the bottom of the water-washing extraction tower 3 is connected to the brominated alkane inlet at the top of the alkali-washing extraction tower 12 via a delivery pump 2 4; the brominated alkane outlet at the bottom of the alkali-washing extraction tower 12 is connected to the inlet of the distillation device via a delivery pump 4 14.

[0018] The hydrobromic acid extraction tower 1 is a rotary disc extraction tower, a packed extraction tower, a pulse extraction tower, a centrifugal extractor, etc.; the water wash extraction tower 3 is a rotary disc extraction tower, a packed extraction tower, a pulse extraction tower, a centrifugal extractor, etc.; the alkali wash extraction tower 12 is a rotary disc extraction tower, a packed extraction tower, a pulse extraction tower, a centrifugal extractor, etc.

[0019] Preferably, the rotary disc extraction tower comprises a middle cylinder, and the upper and lower ends of the cylinder are respectively provided with an upper liquid separation chamber 31 and a lower liquid separation chamber 32. The present invention is beneficial to the stratification after liquid-liquid extraction by providing upper and lower liquid separation chambers to increase the residence time; the rotary disc extraction tower is provided with a plurality of sieve plates 28, a stirring shaft 29, and a turntable 30. The sieve plate 28 is an annular sieve plate, fixed on the inner wall of the cylinder at a certain interval, and the stirring shaft 29 is inserted into the cylinder from the upper liquid separation chamber. A turntable 30 is installed between two adjacent sieve plates 28, and the turntable 30 is fixed by the stirring shaft and driven to rotate by the stirring shaft. The turntable and the sieve plate only exist in the cylinder, and the upper and lower liquid separation chambers are not provided with turntables and sieve plates. The installation of the stirring shaft, the sieve plate and the turntable in the rotary disc extraction tower is common knowledge for those skilled in the art. The turntable is located between the upper and lower sieve plates, and the rotation of the turntable causes shear stress to be generated in the liquid, and the liquid phase is broken into small droplets, generating a vortex motion to increase the contact area. Sieve plates are arranged above and below the turntable to make the wall return to the liquid so that circulation is formed in the column (referring to the cylindrical space formed by the upper and lower sieve plates and the inner wall of the cylinder) to inhibit axial mixing.

[0020] When the hydrobromic acid extraction tower 1 is a rotary disc extraction tower, the upper liquid separation chamber 31 of the hydrobromic acid extraction tower 1 is provided with a high-density material inlet, the lower liquid separation chamber 32 is provided with a low-density material inlet, the bottom is provided with a high-density material outlet, the top is provided with a low-density material outlet, and the low-density material outlet is higher than the high-density material inlet, and the high-density material outlet is lower than the low-density material inlet. When the density of hydrobromic acid is greater than the density of bromoalkane, the bromoalkane reaction liquid is introduced from the bottom, and will flow upward due to the density difference. Hydrobromic acid fills the entire turntable area of ​​the turntable column tower, and will stand and stratify in the upper liquid separation chamber. The liquid separation chamber does not have a turntable and a tray, and what is separated on the upper layer is bromoalkane; due to the introduction of bromoalkane in the lower layer, the bottom liquid separation chamber also needs to stand and stratify, and hydrobromic acid is separated at the bottom.

[0021] When the water-washing extraction tower 3 is a rotary disc extraction tower, the upper liquid separation chamber of the water-washing extraction tower 3 is provided with a brominated alkane inlet, the lower liquid separation chamber is provided with a water inlet, the bottom is provided with a brominated alkane outlet, the top is provided with a water outlet, and the brominated alkane inlet is lower than the water outlet, and the brominated alkane outlet is lower than the water inlet.

[0022] When the alkali washing extraction tower 12 is a rotary disc extraction tower, the upper liquid separation chamber of the alkali washing extraction tower 12 is provided with a brominated alkane inlet, the lower liquid separation chamber is provided with an alkali solution inlet, the bottom is provided with a brominated alkane outlet, and the top is provided with a salt solution outlet and a gas outlet, respectively, and the brominated alkane inlet is lower than the salt solution outlet, and the brominated alkane outlet is lower than the alkali solution inlet.

[0023] Preferably, the outlet of the light-removal tower reflux tank 17 is connected to the reflux port at the top of the light-removal tower 15 and the water inlet of the water-washing extraction tower 3 respectively through the light-removal tower reflux pump 18.

[0024] Preferably, when the distillation device is a double-tower distillation equipment, the outlet of the refining tower reflux tank 23 is connected to the reflux port at the top of the refining tower 21 and the inlet of the product cooler 25 respectively through the refining tower reflux pump 24; when the distillation device is a single-tower separation equipment, the outlet of the refining tower reflux tank 23 is connected to the reflux port at the top of the refining tower 21 and the water inlet of the water washing extraction tower 3 respectively through the refining tower reflux pump 24.

[0025] Preferably, the bottom outlet pipeline of the refining tower 21 is provided with a refining tower kettle pump 27 for extracting heavy components from the kettle.

[0026] As a preferred technical solution of the high-purity brominated alkane continuous distillation equipment described in the present invention, it also includes: a concentrating device; the concentrating device includes a concentrating tower 5, a concentrating tower condenser 6, a concentrating tower reflux tank 7, a recovery water tank 9, an azeotrope collecting tank 10, and a concentrating crystallizer 13; the lower inlet of the concentrating tower is connected to the water outlet of the water washing extraction tower 3, the top gas phase outlet of the concentrating tower 5 is connected to the air inlet of the concentrating tower condenser 6, the liquid outlet of the concentrating tower condenser 6 is connected to the inlet of the concentrating tower reflux tank 7, and the outlet of the concentrating tower reflux tank 7 is respectively connected to the reflux port at the top of the concentrating tower 5, the recovery water tank 9, and the azeotrope collecting tank 10; the bottom liquid outlet of the concentrating tower 5 is connected to the high-density material inlet or the low-density material inlet of the hydrobromic acid extraction tower 1 to pass the hydrobromic acid into the hydrobromic acid extraction tower for reuse; the concentrating crystallizer 13 is connected to the liquid outlet at the top of the alkali washing extraction tower 12, and the liquid outlet of the concentrating crystallizer 13 is connected to the water inlet of the water washing extraction tower 3.

[0027] Preferably, the bottom liquid outlet of the concentration tower 5 is connected to the hydrobromic acid inlet of the hydrobromic acid extraction tower 1 via a delivery pump 3 11.

[0028] Preferably, the outlet of the concentrating tower reflux tank 7 is connected to the inlet of the concentrating tower reflux pump 8, and the outlet of the concentrating tower reflux pump 8 is respectively connected to the reflux port at the top of the concentrating tower 5, the recovery water tank 9, and the azeotrope collecting tank 10, and the alcohol-containing azeotrope and the recovered water are respectively extracted according to the different temperatures at the top of the concentrating tower.

[0029] Preferably, the outlet of the recovery water tank 9 is connected to the water inlet of the water washing extraction tower 3 .

[0030] Another object of the present invention is to provide a high-purity brominated alkane continuous distillation process based on the brominated alkane continuous distillation equipment, comprising the following steps:

[0031] Step (1), three-stage extraction: according to the different densities of hydrobromic acid and bromoalkane, a high-density material is introduced from the high-density material inlet at the top of the hydrobromic acid extraction tower 1, and a low-density material is introduced from the low-density material inlet at the bottom, and the alcohol substances in the reaction liquid of the raw material bromoalkane are extracted by hydrobromic acid in the hydrobromic acid extraction tower, and the bromoalkane and the hydrobromic acid are allowed to stand and separate at the top and bottom, and the low-density material after extraction and separation is discharged from the low-density material outlet at the top, and the high-density material after extraction and separation is discharged from the high-density material outlet at the bottom;

[0032] The brominated alkanes extracted from the hydrobromic acid extraction tower enter the water-washing extraction tower 3 from the top, and water enters the water-washing extraction tower 3 from the bottom. In the water-washing extraction tower, water extracts alcohol substances and hydrobromic acid in the brominated alkanes. The brominated alkanes and the hydrobromic acid are allowed to stand and separate at the top and bottom. Acidic waste water is extracted from the top to the concentration tower, and brominated alkanes are extracted from the bottom. The brominated alkanes extracted from the water-washing extraction tower enter the alkali-washing extraction tower 12 from the top, and the alkali solution enters the bottom of the alkali-washing extraction tower from the bottom. In the alkali-washing extraction tower, the acidic substances in the brominated alkanes react with the alkali to generate bromide salts. The brominated alkanes and the aqueous phase containing the bromide salts are allowed to stand and separate at the top and bottom. The bromide salt solution is extracted from the top, and the brominated alkanes are extracted from the bottom of the alkali-washing extraction tower and enter the rectification device.

[0033] Step (2), refining: when the distillation device is a double-tower distillation device, the brominated alkanes from the bottom of the alkali-washing extraction tower enter the lightness removal tower, the top gas phase is condensed and refluxed into the reflux tank of the lightness removal tower through the condenser of the lightness removal tower, a part of which is refluxed into the tower, and a part is returned to the water-washing extraction tower for reuse, the brominated alkanes in the tower kettle enter the refining tower, the top gas phase is condensed and refluxed into the reflux tank of the refining tower through the condenser of the refining tower, a part of which is refluxed into the tower, a part of which is extracted, and cooled in a product cooler to obtain a brominated alkanes product;

[0034] When the distillation device is a single-tower distillation equipment, the brominated alkanes from the bottom of the alkali washing extraction tower enter the refining tower, and the top gas phase is condensed by the refining tower condenser and refluxed into the refining tower reflux tank, a part of which is refluxed into the tower, and a part is returned to the water washing extraction tower for reuse, and the brominated alkanes are extracted from the middle of the refining tower and cooled in the product cooler to obtain the brominated alkanes product.

[0035] In step (1), the bromoalkane reaction liquid is an organic phase of a raw material alcohol corresponding to a bromoalkane selected from ethyl bromide, propyl bromide, isobromopropane, butyl bromide, etc., and water.

[0036] The content of brominated alkane in the brominated alkane reaction solution is not less than the content of brominated alkane in the azeotrope. The composition of the azeotrope is shown in Table 1.

[0037] Preferably, the purity of the brominated alkane in the brominated alkane reaction liquid is ≥80%wt, the feed temperature is 25-50°C, and the feed pressure is 0.2-0.4MPaG.

[0038] Specifically, the raw material alcohol corresponding to the ethyl bromide is ethanol; the raw material alcohol corresponding to the propyl bromide is n-propyl alcohol; the raw material alcohol corresponding to the isopropyl bromide is isopropyl alcohol; and the raw material alcohol corresponding to the butyl bromide is n-butyl alcohol.

[0039] The concentration of the hydrobromic acid is ≥20%wt, preferably 50%wt, the feed temperature is 25-45°C, and the feed pressure is 0.2-0.4MPaG.

[0040] The amount of hydrobromic acid added (based on solute HBr) is the theoretical amount of hydrobromic acid required for producing brominated alkanes in the brominated alkanes reaction solution.

[0041] Preferably, when the density of hydrobromic acid is higher than that of bromoalkanes, hydrobromic acid is introduced from the high-density material inlet at the top of the hydrobromic acid extraction tower 1, and bromoalkanes reaction solution is introduced from the low-density material inlet at the bottom. In the hydrobromic acid extraction tower, the alcohol substances in the raw material bromoalkanes reaction solution are extracted with hydrobromic acid, and the bromoalkanes and hydrobromic acid are allowed to stand and separate at the top and bottom. The hydrobromic acid after extraction and separation is discharged from the high-density material outlet at the bottom as the reaction raw material of bromoalkanes, and the bromoalkanes after extraction and separation are discharged from the low-density material outlet at the top. When the density of hydrobromic acid is lower than that of bromoalkane, the bromoalkane reaction liquid is introduced from the high-density material inlet at the upper part of the hydrobromic acid extraction tower 1, and the hydrobromic acid is introduced from the low-density material inlet at the lower part. In the hydrobromic acid extraction tower, the hydrobromic acid extracts the alcohol substances in the raw material bromoalkane reaction liquid, and the bromoalkane and the hydrobromic acid are allowed to stand and separate at the top and bottom. The hydrobromic acid after extraction and separation is discharged from the top low-density material outlet as the reaction raw material of bromoalkane, and the bromoalkane after extraction and separation is discharged from the bottom high-density material outlet.

[0042] More preferably, according to the different densities of hydrobromic acid and bromoalkanes, a high-density material is introduced from the high-density material inlet of the upper liquid separation chamber 31 of the hydrobromic acid extraction tower 1, and a low-density material is introduced from the low-density material inlet of the lower liquid separation chamber 32. In the hydrobromic acid extraction tower, hydrobromic acid is used to extract alcohol substances in the reaction liquid of the raw bromoalkanes, and the bromoalkanes and the hydrobromic acid are allowed to stand and separate at the top and bottom. The low-density material after extraction and separation is discharged from the top low-density material outlet, and the high-density material after extraction and separation is discharged from the bottom high-density material outlet.

[0043] Specifically, when the hydrobromic acid extraction tower 1 is a rotary disc extraction tower, when the density of hydrobromic acid is higher than that of bromoalkanes, hydrobromic acid is introduced from the high-density material inlet of the upper liquid separation chamber 31 of the hydrobromic acid extraction tower 1, and bromoalkanes reaction liquid is introduced from the low-density material inlet of the lower liquid separation chamber 32. In the hydrobromic acid extraction tower, the hydrobromic acid extracts the alcohol substances in the raw material bromoalkanes reaction liquid, and the bromoalkanes and the hydrobromic acid are stratified at the top and bottom. The hydrobromic acid after extraction and stratification is discharged from the high-density material outlet at the bottom as the reaction raw material of bromoalkanes, and the bromoalkanes after extraction and stratification are discharged from the high-density material outlet at the bottom. The low-density material outlet at the top is discharged; when the density of hydrobromic acid is lower than that of bromoalkanes, the bromoalkanes reaction liquid is introduced from the high-density material inlet of the upper liquid separation chamber of the hydrobromic acid extraction tower 1, and the hydrobromic acid is introduced from the low-density material inlet of the lower liquid separation chamber. In the hydrobromic acid extraction tower, the hydrobromic acid extracts the alcohol substances in the raw material bromoalkanes reaction liquid, and the bromoalkanes and the hydrobromic acid are allowed to stand and separate at the top and bottom. The hydrobromic acid after extraction and separation is discharged from the low-density material outlet at the top as the reaction raw material of bromoalkanes, and the bromoalkanes after extraction and separation are discharged from the high-density material outlet at the bottom.

[0044] The working temperature of the hydrobromic acid extraction tower is room temperature (25°C±5°C), and the working pressure is normal pressure (0MPaG).

[0045] When the hydrobromic acid extraction tower is a rotary disk extraction tower, the linear speed of the rotary disk of the hydrobromic acid extraction tower is 0.8 to 3 m / s, preferably 1.5 to 2.5 m / s.

[0046] When the water-washing extraction tower 3 is a rotary disc extraction tower, the brominated alkanes extracted from the hydrobromic acid extraction tower enter the water-washing extraction tower 3 from the brominated alkanes inlet of the upper liquid separation chamber of the water-washing extraction tower 3, and water enters the water-washing extraction tower 3 from the water inlet of the lower liquid separation chamber. In the water-washing extraction tower, water extracts alcohol substances and hydrobromic acid in the brominated alkanes, and the brominated alkanes and hydrobromic acid are statically separated and stratified at the top and bottom. Acidic wastewater is extracted from the top to the concentration tower, and brominated alkanes are extracted from the bottom.

[0047] The working temperature of the water-washing extraction tower is room temperature (25°C±5°C), and the working pressure is normal pressure (0MPaG).

[0048] When the water-washing extraction tower is a rotating disk extraction tower, the linear speed of the rotating disk of the water-washing extraction tower is 0.5 to 2.5 m / s, preferably 1 to 2 m / s.

[0049] The ratio of the mass flow rate of the brominated alkane to the mass flow rate of water is 5:1 to 50:1, preferably 10:1 to 40:1.

[0050] When the alkali washing extraction tower 12 is a rotary disc extraction tower, the brominated alkanes produced by the water washing extraction tower enter the alkali washing extraction tower 12 from the brominated alkanes inlet of the upper liquid separation chamber of the alkali washing extraction tower 12, and the alkali solution enters the bottom of the alkali washing extraction tower from the alkali solution inlet of the lower liquid separation chamber. In the alkali washing extraction tower, the acidic substances in the brominated alkanes react with the alkali to form bromide salts. At the top and bottom, the brominated alkanes and the aqueous phase containing the bromide salts are allowed to stand and separate into layers. The bromide salt solution is produced from the top, and the brominated alkanes are produced from the bottom of the alkali washing extraction tower and enter the distillation device.

[0051] The working temperature of the alkali washing extraction tower is 20-35° C., and the working pressure is normal pressure (0 MPaG)-0.002 MPaG.

[0052] The alkali solution is one of sodium bicarbonate solution, potassium bicarbonate solution, lithium bicarbonate solution, sodium hydroxide solution and potassium hydroxide solution, preferably sodium bicarbonate solution. The concentration of the alkali solution is ≥5%wt, the feed temperature is 25-45°C, and the feed pressure is 0.2-0.4MPaG.

[0053] The amount of alkali solution added is to control the pH of the aqueous phase of the alkali washing extraction tower to be 7-10, preferably 7.5-8.

[0054] When the alkali washing extraction tower is a rotary disk extraction tower, the linear speed of the rotary disk of the alkali washing extraction tower is 1 to 3 m / s, preferably 1.5 to 2.2 m / s.

[0055] In step (2), the lightness removal tower 15 and the refining tower 21 are both packed towers. The packing may be a wire mesh packing such as BX or CY, or a plate corrugated packing such as 125X, 125Y, 250X, 250Y, 350X, 350Y, 450X, 450Y, 500X, 500Y, 700X, 700Y, 750X, 750Y or a structured packing with a large mass transfer area (CN207981192U). Preferably, 125X, 125Y, 250X, 250Y, 350X, 350Y, 450X, 450Y, 500X, 500Y or a structured packing with a large mass transfer area (CN207981192U) may be used.

[0056] When the distillation device is a double-tower distillation equipment, the pressure of the lightness removal tower 15 is 0-0.1MPaG, preferably 0-10KPaG, the operating temperature of the tower bottom is 80-110°C, preferably 90-100°C, and the reflux ratio is 5-10, preferably 7-9; the pressure of the refining tower 21 is 0-0.1MPaG, preferably 0-10KPaG, the operating temperature of the tower bottom is 90-120°C, preferably 95-110°C, and the reflux ratio is 2-10, preferably 5-8.

[0057] The temperature of the lightness removal tower condenser 16 is 30-70°C, preferably 35-50°C.

[0058] When the distillation device is a double-tower distillation device, the temperature of the refining tower condenser 22 is 30-70°C, preferably 35-50°C.

[0059] When the distillation device is a single-tower distillation device, the pressure of the refining tower 21 is 0-0.1 MPaG, preferably 0-10 KPaG, the operating temperature of the tower bottom is 90-120°C, preferably 95-110°C, and the reflux ratio is 3-10, preferably 6-9.

[0060] When the distillation device is a single-tower distillation device, the temperature of the refining tower condenser 22 is 30-70°C, preferably 35-50°C.

[0061] The temperature of the product cooler 25 is 30-60°C, preferably 35-40°C.

[0062] The purity of the brominated alkane product is ≥99.5%wt.

[0063] The recombinant components in the refining tower kettle are transported to the outside through the refining tower kettle pump.

[0064] The high-purity brominated alkane continuous distillation process of the present invention further comprises: step (3), concentration: the acidic wastewater from the top of the water washing extraction tower enters the concentration tower 5, the generated gas phase is condensed by the concentration tower condenser, the liquid phase is refluxed to the concentration tower reflux tank, a part of which is refluxed to the concentration tower, and a part of which is respectively extracted to the recovery water tank and the azeotrope collecting tank according to different extraction temperatures; the water phase in the recovery water tank is returned to the water washing extraction tower, the alcohol-containing azeotrope in the azeotrope collecting tank is used as the brominated alkane reaction raw material, the tower kettle is the hydrobromic acid obtained by concentration, and is returned to the hydrobromic acid extraction tower 1 for application; the bromide salt solution from the alkali washing extraction tower enters the concentration crystallizer for concentration and crystallization to obtain bromide salt solid, and the water phase generated by the concentration and crystallization enters the water washing extraction tower.

[0065] In step (3), the concentration tower 5 is a packed tower, and the packing may be a wire mesh packing such as BX, CY, or a plate corrugated packing such as 125X, 125Y, 250X, 250Y, 350X, 350Y, 450X, 450Y, 500X, 500Y, 700X, 700Y, 750X, 750Y, or a structured packing with a large mass transfer area (CN207981192U), preferably 125X, 125Y, 250X, 250Y, 350X, 350Y, 450X, 450Y, 500X, 500Y.

[0066] The pressure of the concentrating tower 5 is 0-0.1 MPaG, preferably 0-10 KPaG, the operating temperature of the tower bottom is 110-140° C., preferably 120-130° C., and the reflux ratio is 1-10, preferably 2-5. Specifically, the concentrating tower 5 is heated by a steam coil inside the concentrating tower.

[0067] The temperature of the concentration tower condenser 6 is 45-70°C, preferably 50-65°C.

[0068] Preferably, when the top temperature of the concentrator tower is less than the azeotropic point, the gas phase produced by the concentrator tower is condensed through the concentrator tower condenser, and the liquid phase is refluxed into the concentrator tower reflux tank, a part of which is refluxed into the concentrator tower, and a part is extracted into the azeotropic collection tank; when the top temperature of the concentrator tower is ≥ the azeotropic point, the gas phase produced by the concentrator tower is condensed through the concentrator tower condenser, and the liquid phase is refluxed into the concentrator tower reflux tank, a part of which is refluxed into the concentrator tower, and a part is extracted into the recovery water tank.

[0069] The process principle of the present invention:

[0070] The existing process directly purifies the brominated alkane after the reaction, but since the brominated alkane forms an azeotrope with the raw material alcohol substance and water, the product purity is low and the yield of the high-purity product is low. The present invention sequentially washes the brominated alkane with hydrobromic acid, water and alkali solution in three stages to remove the alcohol substance in the brominated alkane, and then distills the brominated alkane to obtain a high-purity product. The product has high purity, and the raw material and product are used to extract the alcohol substance to recover the reaction raw material, and the product yield is high.

[0071] The existing process will produce wastewater after alkaline washing with brominated alkanes. This process directly concentrates and crystallizes the bromide salt solution. The obtained bromide salt can be sold, and the recovered water phase can be applied to the water washing extraction tower, and no wastewater is generated in the system.

[0072] In the existing process, the brominated alkane products need to be dehydrated by molecular sieves. In this process, the water is further removed by oil-water separation in the alkaline washing extraction tower and azeotropic distillation in the lightness removal tower. The subsequent brominated alkane products do not need to be dried and dehydrated again, and no solid waste is generated in the system.

[0073] Compared with the prior art, the present invention has the following beneficial effects:

[0074] (1) Compared with the traditional process, the brominated alkane distillation process of the present invention adopts a combined process of three-stage extraction and two-stage refining to recover alcohol substances, with a large processing capacity, a higher purity of the brominated alkane product (≥99.5%wt), which can meet the requirements of the pharmaceutical field and a higher product yield.

[0075] (2) The present invention uses salt-containing wastewater concentration and crystallization, acidic water concentration and recovery, and water and acid are circulated in the system, so that no wastewater is generated in the entire process.

[0076] (3) The present invention adopts extraction standing oil-water separation and azeotropic light removal to effectively remove water from brominated alkanes without the need for further drying, and the system generates no solid waste.

[0077] (4) The present invention adopts a rotary disc column for extraction and separation, which has simple equipment, high tower efficiency and small equipment size. BRIEF DESCRIPTION OF THE DRAWINGS

[0078] Figure 1 The schematic diagram of the structure of the double-tower device of the high-purity brominated alkane continuous distillation device of the present invention is shown in FIG.

[0079] Figure 2 The figure is a schematic diagram of the structure of a single-tower device for continuous distillation of high-purity brominated alkanes according to the present invention.

[0080] Figure 3 This is a schematic diagram of the structure of the rotary disc extraction tower.

[0081] Figure 4 This is the front view of the internal parts of the turntable extraction tower.

[0082] Figure 5 This is a top view of the internal components of the rotary disc extraction tower.

[0083] In the figure, 1-hydrobromic acid extraction tower, 2-delivery pump 1, 3-water washing extraction tower, 4-delivery pump 2, 5-concentration tower, 6-concentration tower condenser, 7-concentration tower reflux tank, 8-concentration tower reflux pump, 9-recovery water tank, 10-azeotrope collection tank, 11-delivery pump 3, 12-alkali washing extraction tower, 13-concentration crystallizer, 14-delivery pump 4, 15-light removal tower, 16-light removal tower condenser, 17-de Light tower reflux tank, 18-removal of light tower reflux pump, 19-removal of light tower reboiler, 20-removal of light tower kettle pump, 21-refining tower, 22-refining tower condenser, 23-refining tower reflux tank, 24-refining tower reflux pump, 25-product cooler, 26-refining tower reboiler, 27-refining tower kettle pump, 28-sieve plate, 29-agitation shaft, 30-turntable, 31-upper liquid separation chamber, 32-lower liquid separation chamber. DETAILED DESCRIPTION

[0084] The technical solution of the present invention is further described below in conjunction with embodiments. The following embodiments are illustrative rather than restrictive, and the protection scope of the present invention cannot be limited by the following embodiments. Example 1

[0085] like Figure 1 , Figure 3 , Figure 4 and Figure 5 As shown, a high-purity brominated alkane continuous distillation device includes an extraction device, a concentration device, and a distillation device.

[0086] The extraction device comprises a hydrobromic acid extraction tower 1, a delivery pump 1 2, a water washing extraction tower 3, a delivery pump 2 4, an alkali washing extraction tower 12, and a delivery pump 4 14; the hydrobromic acid extraction tower 1, the water washing extraction tower 3, and the alkali washing extraction tower 12 are all turntable extraction towers; the turntable extraction tower comprises a middle cylinder, and the upper and lower ends of the cylinder are respectively provided with an upper liquid separation chamber 31 and a lower liquid separation chamber 32, and the inner diameters of the upper and lower liquid separation chambers are larger than the inner diameter of the cylinder; the turntable extraction tower is provided with a plurality of sieve plates 28, a stirring shaft 29, and a turntable 30, the sieve plate 28 is an annular sieve plate, fixed on the inner wall of the cylinder at a certain interval, the stirring shaft 29 is inserted from the upper liquid separation chamber into the cylinder, and a turntable 30 is installed between two adjacent sieve plates 28, and the turntable 30 is fixed by the stirring shaft, the turntable and the sieve plate exist only in the cylinder, and the upper and lower liquid separation chambers are not provided with turntables and sieve plates. The upper liquid separation chamber of the hydrobromic acid extraction tower 1 is provided with a high-density material inlet (in this embodiment, the high-density material inlet is used for hydrobromic acid feeding, also known as the hydrobromic acid inlet) for introducing hydrobromic acid used to extract alcohol substances in the bromoalkane reaction liquid, the lower liquid separation chamber is provided with a low-density material inlet (in this embodiment, the low-density material inlet is used for bromoalkane reaction liquid feeding, also known as the bromoalkane reaction liquid inlet, the bottom is provided with a high-density material outlet (in this embodiment, the high-density material outlet is used for hydrobromic acid discharging, also known as the hydrobromic acid outlet) for discharging the hydrobromic acid after extraction and stratification, the top is provided with a low-density material outlet (in this embodiment, the low-density material outlet is used for bromoalkane discharging, also known as the bromoalkane outlet) for discharging the bromoalkane after extraction and stratification, the bromoalkane outlet is higher than the hydrobromic acid inlet by 1.5m, and the hydrobromic acid outlet is lower than the bromoalkane reaction liquid inlet by 1.5m; the hydrobromic acid extraction tower 1 The brominated alkane outlet is connected to the brominated alkane inlet of the upper liquid separation chamber of the water washing extraction tower 3 through a delivery pump 1 2; the lower liquid separation chamber of the water washing extraction tower 3 is provided with a water inlet, a brominated alkane outlet is provided at the bottom, and a water outlet is provided at the top. The brominated alkane inlet is 2m lower than the water outlet, and the brominated alkane outlet is 2m lower than the water inlet; the water outlet of the water washing extraction tower 3 is connected to the inlet of the concentration device; the brominated alkane outlet of the water washing extraction tower 3 is connected to the brominated alkane inlet of the upper liquid separation chamber of the alkali washing extraction tower 12 through a delivery pump 2 4; the lower liquid separation chamber of the alkali washing extraction tower 12 is provided with an alkali solution inlet, a brominated alkane outlet is provided at the bottom, and a salt solution outlet and an air outlet are provided at the top respectively. The brominated alkane inlet is 1.5m lower than the salt solution outlet, and the brominated alkane outlet is 1.5m lower than the alkali solution inlet; the brominated alkane outlet of the alkali washing extraction tower 12 is connected to the inlet of the distillation device through a delivery pump 4 14.

[0087] The concentrating device comprises a concentrating tower 5, a concentrating tower condenser 6, a concentrating tower reflux tank 7, a concentrating tower reflux pump 8, a recycling water tank 9, an azeotrope collecting tank 10, a delivery pump 3 11, and a concentrating crystallizer 13; the concentrating tower 5 is a packed tower (500Y plate corrugated packing), the top gas phase outlet of the concentrating tower 5 is connected to the air inlet of the concentrating tower condenser 6, the liquid outlet of the concentrating tower condenser 6 is connected to the inlet of the concentrating tower reflux tank 7, the outlet of the concentrating tower reflux tank is connected to the inlet of the concentrating tower reflux pump 8, the outlet of the concentrating tower reflux pump 8 is respectively connected to the reflux port at the top of the concentrating tower 5, the recycling water tank 9, and the azeotrope collecting tank 10, and the outlet of the recycling water tank 9 is connected to the water inlet of the water washing extraction tower 3. The bottom liquid outlet of the concentrating tower 5 is connected to the hydrobromic acid inlet of the hydrobromic acid extraction tower 1 through a delivery pump 3 11. The concentration crystallizer 13 is connected to the liquid outlet at the top of the alkali washing extraction tower 12 , and the liquid outlet of the concentration crystallizer 13 is connected to the water inlet of the water washing extraction tower 3 .

[0088] The distillation device adopts a double-tower distillation equipment, including a light-removal tower 15, a light-removal tower condenser 16, a light-removal tower reflux tank 17, a light-removal tower reflux pump 18, a light-removal tower reboiler 19, a light-removal tower kettle pump 20, a refining tower 21, a refining tower condenser 22, a refining tower reflux tank 23, a refining tower reflux pump 24, a product cooler 25, a refining tower reboiler 26, and a refining tower kettle pump 27; the light-removal tower 15 is a packed tower (500Y plate corrugated packing The inlet of the light-removing tower 15 is connected to the brominated alkane outlet at the bottom of the alkali washing extraction tower 12, the light-removing tower 15 is equipped with a light-removing tower reboiler 19, the gas phase outlet at the top of the light-removing tower 15 is connected to the air inlet of the light-removing tower condenser 16, the liquid outlet of the light-removing tower condenser 16 is connected to the inlet of the light-removing tower reflux tank 17, and the outlet of the light-removing tower reflux tank 17 is connected to the reflux port at the top of the light-removing tower 15 and the water inlet of the water washing extraction tower 3 through the light-removing tower reflux pump 18. The bottom outlet of the light-removing tower 15 is connected to the inlet of the refining tower 21 through the light-removing tower kettle pump 20. The refining tower 21 is a packed tower (350Y plate corrugated packing), and the refining tower 21 is equipped with a refining tower reboiler 26, and the gas phase outlet at the top of the refining tower 21 is connected to the air inlet of the refining tower condenser 22, and the liquid outlet of the refining tower condenser 22 is connected to the inlet of the refining tower reflux tank 23, and the outlet of the refining tower reflux tank 23 is respectively connected to the reflux port at the top of the refining tower 21 and the inlet of the product cooler 25 through the refining tower reflux pump 24, and the brominated alkane product is extracted at the outlet of the product condenser 25. The outlet pipeline at the bottom of the refining tower 21 is provided with a refining tower kettle pump 27 for extracting the heavy components in the tower kettle. Example 2

[0089] The continuous distillation process of high-purity butyl bromide based on the equipment of Example 1 comprises:

[0090] Step (1), extraction: the raw material bromobutane reaction liquid (bromobutane: 81%wt, butanol: 18%wt, the balance is water; temperature 30°C, pressure 0.25MPaG) continuously enters the hydrobromic acid extraction tower 1 (temperature 30°C, pressure 0MPaG) from the bromoalkane reaction liquid inlet of the lower liquid separation chamber, and hydrobromic acid (concentration: 50%wt, temperature 30°C, pressure 0.25MPaG) continuously enters the hydrobromic acid extraction tower 1 from the hydrobromic acid inlet of the upper liquid separation chamber, the mass flow rate of hydrobromic acid is 1.18 times the mass flow rate of the bromobutane reaction liquid, and in the hydrobromic acid extraction tower (the linear speed of the turntable is 1.7 m / s), hydrobromic acid extracts the unreacted butanol in the reaction liquid of raw material bromobutyl, and bromobutyl and hydrobromic acid are allowed to stand and separate in the upper and lower liquid separation chambers (in the upper and lower liquid separation chambers, bromobutyl is in the upper layer and hydrobromic acid is in the lower layer), and hydrobromic acid (purity: 49.5%wt, temperature 30°C, pressure 0.25MPaG) is extracted from the bottom of the hydrobromic acid extraction tower as a raw material for producing bromobutyl, and the layered bromobutyl is extracted from the top. The extracted bromobutyl is transported by a delivery pump 2 and enters a water washing extraction tower 3 (temperature 30°C, pressure 0MPaG) from the brominated alkane inlet of the upper liquid separation chamber, and is extracted from the bottom of the water washing extraction tower 3 Water is introduced into the top of the extraction tower, and the mass flow rate of bromobutyl is 10 times the mass flow rate of water. In the water washing extraction tower (the linear speed of the turntable is 1.5 m / s), water extracts the butanol and dissolved hydrobromic acid in the bromobutyl that have not been completely extracted by the hydrobromic acid. In the upper and lower liquid separation chambers, bromobutyl and hydrobromic acid are allowed to stand and separate. Acidic waste water is extracted from the top to the concentration tower 5, and bromobutyl is extracted from the bottom. The extracted bromobutyl is transported by a delivery pump 24 and enters an alkali washing extraction tower 12 (temperature 31° C., pressure 0.002 MPaG) from the bromoalkane inlet of the upper liquid separation chamber. Sodium bicarbonate solution (concentration 200 g / cm2) is introduced from the alkali liquor inlet of the lower liquid separation chamber of the alkali washing extraction tower. : 5%wt, temperature 30°C, pressure 0.25MPaG) to control the pH of the aqueous phase of the alkali washing extraction tower at 7.5, in the alkali washing extraction tower (the linear speed of the turntable is 1.7m / s), the acidic substance in the bromobutyl reacts with the sodium bicarbonate to generate sodium bromide, in the upper liquid separation chamber and the lower liquid separation chamber, the bromobutyl and the aqueous phase containing the sodium bromide are allowed to stand for stratification, the sodium bromide solution is extracted from the top to the concentrating crystallizer 13, and the bromobutyl crude product (purity: 95%wt, temperature 30°C, pressure 0.25MPaG) is extracted from the bottom, and the bromobutyl crude product is transported by the delivery pump 29 14 and enters the lightness removal tower 15 from the middle;

[0091] Step (2), concentration: The acidic wastewater from the top of the water washing extraction tower enters the concentration tower 5 (tower bottom temperature 120°C, pressure 0.005 MPaG, reflux ratio 2), is heated by the steam coil inside the concentration tower, and the generated gas phase is condensed by the concentration tower condenser 6 (temperature 70°C), and the liquid phase is refluxed to the concentration tower reflux tank 7, a part of which is refluxed to the concentration tower 5 through the concentration tower reflux pump 8, and a part is extracted. When the top temperature of the concentration tower is less than 95°C, it is extracted to the azeotrope collection tank 1 0 (water: 42.5%wt, butanol: 57.5%wt), when the tower top temperature is ≥95°C, it is extracted into the recovery water tank 9; the water phase in the recovery water tank 9 is returned from the bottom to the water washing extraction tower 3, and the alcohol-containing azeotrope in the azeotrope collecting tank 10 is used as the raw material for producing bromobutyl; the concentrated hydrobromic acid (purity: 50%wt, temperature 120°C, pressure 0.25MPaG) is obtained in the tower kettle of the concentration tower, and the hydrobromic acid is transported to the hydrobromic acid extraction tower 1 through the delivery pump 3 11 for application;

[0092] The sodium bromide solution from the alkali washing extraction tower enters the concentration crystallizer 13, and is concentrated to obtain sodium bromide solid. The aqueous phase produced after concentration enters the water washing extraction tower 3;

[0093] Step (3), refining: the crude bromobutyl extracted from the bottom of the alkali washing extraction tower enters the lightness removal tower 15 (tower bottom operating temperature 110°C, pressure 0.002MPaG, reflux ratio 7) from the middle, is steam-heated by the lightness removal tower reboiler 19, and the top gas phase is condensed by the lightness removal tower condenser 16 (temperature 45°C) to obtain a water-containing azeotrope (water: 10.7%wt, butanol: 89.3%wt), the water-containing azeotrope is refluxed to the lightness removal tower reflux tank 17, and then passes through the lightness removal tower reflux pump 18, a part of which is refluxed to the lightness removal tower 15, and a part is returned to the water washing extraction tower 1 for application, and the bromobutyl in the bottom of the lightness removal tower 15 is refluxed to the lightness removal tower 15. The de-light tower kettle pump 20 is transported from the middle to the refining tower 21 (the operating temperature of the tower kettle is 110°C, the pressure is 0.002MPaG, and the reflux ratio is 5), and the tower top gas phase is condensed and refluxed to the refining tower reflux tank 23 through the refining tower condenser 22 (temperature 50°C), and then passes through the refining tower reflux pump 24, part of which is refluxed to the refining tower, and part of which is cooled through the product cooler 25 (temperature 40°C) to obtain a bromobutyl product (purity: 99.7%wt, water content: 100ppm, temperature 40°C, pressure 0.25MPaG), with a product yield of 95%. The recombinant components of the tower kettle of the refining tower 21 are transported to the outside through the refining tower kettle pump 27. Example 3

[0094] The continuous distillation process of high-purity ethyl bromide based on the equipment of Example 1 comprises:

[0095] Step (1), extraction: the raw material bromoethane reaction liquid (bromoethane: 98.2%wt, ethanol: 1.6%wt, the balance is water; temperature 30°C, pressure 0.25MPaG) continuously enters the hydrobromic acid extraction tower 1 (temperature 30°C, pressure 0MPaG) from the bromoalkane reaction liquid inlet of the lower liquid separation chamber, and hydrobromic acid (concentration: 50%wt, temperature 30°C, pressure 0.25MPaG) continuously enters the hydrobromic acid extraction tower 1 from the hydrobromic acid inlet of the upper liquid separation chamber, the mass flow rate of hydrobromic acid is 1.5 times the mass flow rate of the bromoethane reaction liquid, and in the hydrobromic acid extraction tower (the rotary table linear speed is 1.6m / s), the hydrobromic acid extracts the unreacted bromoethane in the raw material bromoethane reaction liquid. After the ethanol is used up, ethyl bromide and hydrobromic acid are allowed to stand and separate in the upper and lower liquid separation chambers (ethyl bromide is in the upper layer and hydrobromic acid is in the lower layer in the upper and lower liquid separation chambers), hydrobromic acid (purity: 49.8%wt, temperature 30°C, pressure 0.25MPaG) is extracted from the bottom of the hydrobromic acid extraction tower as a raw material for producing ethyl bromide, and the layered ethyl bromide is extracted from the top. The ethyl bromide is transported by a delivery pump 2 and enters a water washing extraction tower 3 (temperature 30°C, pressure 0MPaG) from the brominated alkane inlet of the upper liquid separation chamber. Water is introduced from the bottom of the water washing extraction tower 3, and the mass flow rate of ethyl bromide is The mass flow rate is 10 times of that of water. In the water washing extraction tower (the linear speed of the rotary table is 1.6 m / s), the ethanol and the dissolved hydrobromic acid in the ethyl bromide that have not been completely extracted by the hydrobromic acid are extracted by water. The bromoalkane and the hydrobromic acid are stratified in the upper and lower liquid separation chambers. The acidic wastewater is extracted from the top to the concentration tower 5, and the ethyl bromide is extracted from the bottom. The extracted ethyl bromide is transported by the delivery pump 24 and enters the alkali washing extraction tower 12 (temperature 31°C, pressure 0.002 MPaG) from the bromoalkane inlet of the upper liquid separation chamber. Sodium bicarbonate solution (concentration: 5%wt, temperature 30 ℃, pressure 0.25 MPaG) to control the pH of the aqueous phase of the alkali washing extraction tower at 7.5, in the alkali washing extraction tower (the linear speed of the turntable is 1.7 m / s), the acidic substance in the ethyl bromide reacts with sodium bicarbonate to generate sodium bromide, the brominated alkane and the aqueous phase containing sodium bromide are allowed to stand and separate in the upper and lower liquid separation chambers, the sodium bromide solution is extracted from the top to the concentration crystallizer 13, and the ethyl bromide crude product (purity: 95%wt, temperature 30 ℃, pressure 0.25 MPaG) is extracted from the bottom, and the extracted ethyl bromide crude product is transported by the delivery pump 24 14 and enters the light removal tower 15 from the middle;

[0096] Step (2), concentration: the acidic wastewater from the top of the water washing extraction tower enters the concentration tower 5 (tower bottom temperature 120°C, pressure 0.005 MPaG, reflux ratio 2), is heated by the steam coil inside the concentration tower, and the generated gas phase is condensed by the concentration tower condenser 6 (temperature 35°C), and the liquid phase is refluxed to the concentration tower reflux tank 7, a part of which is refluxed to the concentration tower 5 through the concentration tower reflux pump 8, and a part is extracted. When the top temperature of the concentration tower is less than 80°C, it is extracted to the azeotrope The water in the collecting tank 10 (water: 4.4%wt, ethanol: 95.6%wt) is extracted to the water recovery tank 9 when the tower top temperature is ≥80°C; the water phase in the water recovery tank 9 is returned to the water washing extraction tower 3 from the bottom, and the alcohol-containing azeotrope in the azeotrope collecting tank 10 is used as the raw material of ethyl bromide; the concentrated hydrobromic acid (purity: 50%wt, temperature 120°C, pressure 0.25MPaG) obtained in the tower kettle of the concentration tower is transported to the hydrobromic acid extraction tower 1 through the delivery pump 3 11 for application;

[0097] The sodium bromide solution from the alkali washing extraction tower enters the concentration crystallizer 13, and is concentrated to obtain sodium bromide solid. The aqueous phase produced after concentration enters the water washing extraction tower 3;

[0098] Step (3), refining: the crude ethyl bromide extracted from the bottom of the alkali washing extraction tower enters the lightness removal tower 15 (tower bottom operating temperature 80°C, pressure 0.002MPaG, reflux ratio 9) from the middle, is heated by steam through the lightness removal tower reboiler 19, and the top gas phase is condensed by the lightness removal tower condenser 16 (temperature 35°C) to obtain a water-containing azeotrope, which is refluxed into the lightness removal tower reflux tank 17, and a part of it is refluxed into the lightness removal tower 15 through the lightness removal tower reflux pump 18, and a part of it is returned to the water washing extraction tower 1 for application, and the ethyl bromide in the tower bottom of the lightness removal tower 15 is pumped out by the tower bottom pump 20 of the lightness removal tower It is sent to the middle of the refining tower 21 (tower bottom operating temperature 90°C, pressure 0.002MPaG, reflux ratio 8), and steam heated by the refining tower reboiler 26. The top gas phase is condensed and refluxed to the refining tower reflux tank 23 through the refining tower condenser 22 (temperature 37°C), and part of it is refluxed to the refining tower through the refining tower reflux pump 24, and part of it is cooled through the product cooler 25 (temperature 35°C) to obtain ethyl bromide product (purity: 99.9%wt, water content: 80PPm, temperature 35°C, pressure 0.25MPaG), with a product yield of 98%. The recombinant components of the tower bottom of the refining tower 21 are transported to the outside through the refining tower tower bottom pump 27. Example 4

[0099] The continuous distillation process of high-purity bromopropane based on the equipment of Example 1 comprises:

[0100] Step (1), extraction: the raw material bromopropane reaction liquid (bromopropane: 95.8%wt, propanol: 4.1%wt, the balance is water; temperature 30°C, pressure 0.25MPaG) continuously enters the hydrobromic acid extraction tower 1 (temperature 30°C, pressure 0MPaG) from the bromoalkane reaction liquid inlet of the lower liquid separation chamber, and hydrobromic acid (concentration: 50%wt, temperature 30°C, pressure 0.25MPaG) continuously enters the hydrobromic acid extraction tower 1 from the hydrobromic acid inlet of the upper liquid separation chamber, the mass flow rate of hydrobromic acid is 1.31 times the mass flow rate of the bromopropane reaction liquid, and in the hydrobromic acid extraction tower (the linear speed of the turntable is 1.8m / s), the hydrobromic acid extracts the unreacted The n-propanol is completely removed, and bromopropane and hydrobromic acid are allowed to stand and separate in the upper and lower liquid separation chambers (bromopropane is in the upper layer and hydrobromic acid is in the lower layer in the upper and lower liquid separation chambers). Hydrobromic acid (purity: 49.3%wt, temperature 30°C, pressure 0.25MPaG) is extracted from the bottom of the hydrobromic acid extraction tower as a raw material for producing bromopropane, and the layered bromopropane is extracted from the top. The extracted bromopropane is transported by a delivery pump 2 and enters a water washing extraction tower 3 (temperature 30°C, pressure 0MPaG) from the brominated alkane inlet of the upper liquid separation chamber. Water is introduced from the bottom of the water washing extraction tower 3. The mass of bromopropane The flow rate is 10 times the mass flow rate of water. In the water washing extraction tower (the linear speed of the turntable is 1.6m / s), water extracts the n-propanol and dissolved hydrobromic acid in the bromopropane that have not been completely extracted by the hydrobromic acid. The bromopropane and the hydrobromic acid are allowed to stand and stratify in the upper and lower liquid separation chambers. The acidic wastewater is extracted from the top to the concentration tower 5, and the bromopropane is extracted from the bottom. The extracted bromopropane is transported by the delivery pump 24 and enters the alkali washing extraction tower 12 (temperature 30.5°C, pressure 0.002MPaG) from the brominated alkane inlet of the upper liquid separation chamber. Sodium bicarbonate solution (concentration: 5%wt) is introduced from the bottom of the alkali washing extraction tower. , temperature 30°C, pressure 0.25MPaG) to control the pH of the aqueous phase of the alkali washing extraction tower at 7.8, in the alkali washing extraction tower (the linear speed of the turntable is 1.6m / s), the acidic substance in the bromopropane reacts with sodium bicarbonate to generate sodium bromide, and the bromopropane and the aqueous phase containing sodium bromide are allowed to stand and separate in the upper and lower liquid separation chambers, and the sodium bromide solution is extracted from the top to the concentrating crystallizer 13, and the bromopropane crude product (purity: 98%wt, temperature 30°C, pressure 0.25MPaG) is extracted from the bottom, and the extracted bromopropane crude product is transported by the delivery pump 414 and enters the light removal tower 15 from the middle;

[0101] Step (2), concentration: the acidic wastewater from the top of the water washing extraction tower enters the concentration tower 5 (temperature 120°C, pressure 0.005 MPaG, reflux ratio 2), is heated by the steam coil inside the concentration tower, and the generated gas phase is condensed by the concentration tower condenser 6 (temperature 50°C), and the liquid phase is refluxed to the concentration tower reflux tank 7, a part of which is refluxed to the concentration tower 5 through the concentration tower reflux pump 8, and a part is extracted. When the temperature at the top of the concentration tower is less than 89°C, it is extracted to the azeotropic collection Tank 10 (water: 31%wt, propanol: 69%wt), when the tower top temperature is ≥89°C, it is extracted into the recovery water tank 9; the water phase in the recovery water tank 9 is returned to the water washing extraction tower 3 from the bottom, and the alcohol-containing azeotrope in the azeotrope collection tank 10 is used as the raw material of bromopropane; the concentrated hydrobromic acid (purity: 52%wt, temperature 125°C, pressure 0.25MPaG) is obtained in the tower kettle of the concentration tower, and the hydrobromic acid is transported to the hydrobromic acid extraction tower 1 through the delivery pump 3 11 for application;

[0102] The sodium bromide solution from the alkali washing extraction tower enters the concentration crystallizer 13, and is concentrated to obtain sodium bromide solid. The aqueous phase produced after concentration enters the water washing extraction tower 3;

[0103] Step (3), refining: the crude bromopropane extracted from the bottom of the alkali washing extraction tower enters the lightness removal tower 15 (tower bottom operating temperature 100°C, pressure 0.002MPaG, reflux ratio 8) from the middle, is heated by steam through the lightness removal tower reboiler 19, and the top gas phase is condensed by the lightness removal tower condenser 16 (temperature 50°C) to obtain a water-containing azeotrope, which is refluxed into the lightness removal tower reflux tank 17, and a part of it is refluxed into the lightness removal tower 15 through the lightness removal tower reflux pump 18, and a part of it is returned to the water washing extraction tower 1 for application, and the bromopropane in the bottom of the lightness removal tower 15 is transported by the lightness removal tower bottom pump 20 Enter the refining tower 21 from the middle (tower bottom operating temperature 105°C, pressure 0.002MPaG, reflux ratio 7), steam heating through the refining tower reboiler 26, the top gas phase is condensed and refluxed to the refining tower reflux tank 23 through the refining tower condenser 22 (temperature 50°C), part of it is refluxed to the refining tower through the refining tower reflux pump 24, and part of it is cooled through the product cooler 25 (temperature 40°C) to obtain bromopropane product (purity: 99.7%wt, water content: 100PPm, temperature 40°C, pressure 0.25MPaG), the product yield is 96%. The recombinant components of the tower bottom of the refining tower 21 are transported to the outside through the refining tower tower bottom pump 27. Example 5

[0104] like Figure 2 As shown, the double-tower distillation equipment in Example 1 is adjusted to a single-tower distillation equipment, and the rest is the same as Example 1.

[0105] The distillation device includes a refining tower 21, a refining tower condenser 22, a refining tower reflux tank 23, a refining tower reflux pump 24, a product cooler 25, a refining tower reboiler 26, and a refining tower kettle pump 27; the refining tower 21 is a packed tower (350Y plate corrugated packing), the inlet of the refining tower 21 is connected to the brominated alkane outlet at the bottom of the alkali washing extraction tower 12, and the refining tower 21 is equipped with a refining tower reboiler 26, and the refining tower 2 The gas phase outlet at the top of the refining tower 21 is connected to the air inlet of the refining tower condenser 22, the liquid outlet of the refining tower condenser 22 is connected to the inlet of the refining tower reflux tank 23, the outlet of the refining tower reflux tank 23 is respectively connected to the reflux port at the top of the refining tower 21 and the water inlet of the water washing extraction tower 3 through the refining tower reflux pump 24; the discharge port in the middle of the refining tower 21 is connected to the inlet of the product condenser 25, and the brominated alkane product is extracted at the outlet of the product condenser 25.

[0106] Step (1), extraction: the raw material bromoethane reaction liquid (bromoethane: 98.2%wt, ethanol: 1.6%wt, the balance is water; temperature 30°C, pressure 0.25MPaG) continuously enters the hydrobromic acid extraction tower 1 (temperature 30°C, pressure 0MPaG) from the bromoalkane reaction liquid inlet of the lower liquid separation chamber, and hydrobromic acid (purity: 50%wt, temperature 30°C, pressure 0.25MPaG) continuously enters the hydrobromic acid extraction tower 1 from the hydrobromic acid inlet of the upper liquid separation chamber, the mass flow rate of hydrobromic acid is 1.5 times the mass flow rate of the bromoethane reaction liquid, and in the hydrobromic acid extraction tower (the rotary table linear speed is 1.6m / s), the hydrobromic acid extracts the unreacted bromoethane reaction liquid of the raw material. ethanol, bromoalkane and hydrobromic acid are allowed to stand and separate in the upper and lower liquid separation chambers (in the upper and lower liquid separation chambers, bromoethane is in the upper layer and hydrobromic acid is in the lower layer), hydrobromic acid (purity: 49.8%wt, temperature 30°C, pressure 0.25MPaG) is extracted from the bottom of the hydrobromic acid extraction tower as a raw material for producing bromoethane, and the layered bromoethane is extracted from the top. The extracted bromoethane is transported by a delivery pump 2 and enters a water washing extraction tower 3 (temperature 30°C, pressure 0MPaG) from the bromoalkane inlet of the upper liquid separation chamber, and water is introduced from the bottom of the water washing extraction tower 3. The mass of bromoethane The flow rate is 10 times the mass flow rate of water. In the water washing extraction tower (the linear speed of the turntable is 1.6 m / s), water extracts the ethanol and dissolved hydrobromic acid in the ethyl bromide that have not been completely extracted by the hydrobromic acid. The ethyl bromide and the hydrobromic acid are allowed to stand and stratify in the upper and lower liquid separation chambers. The acidic waste water is extracted from the top to the concentration tower 5, and the ethyl bromide is extracted from the bottom. The extracted ethyl bromide is transported by the delivery pump 24 and enters the alkali washing extraction tower 12 (temperature 31°C, pressure 0.002 MPaG) from the brominated alkane inlet of the upper liquid separation chamber. Sodium bicarbonate solution (concentration: 5%wt, The pH value of the aqueous phase of the alkali washing extraction tower is controlled at 7.5 (temperature 30°C, pressure 0.25MPaG). In the alkali washing extraction tower (rotating plate linear speed is 1.7m / s), the acidic substance in the ethyl bromide reacts with sodium bicarbonate to generate sodium bromide. The bromoalkane and the aqueous phase containing sodium bromide are allowed to stand and separate in the upper and lower liquid separation chambers. The sodium bromide solution is extracted from the top to the concentrating crystallizer 13, and the crude ethyl bromide (purity: 95%wt, temperature 30°C, pressure 0.25MPaG) is extracted from the bottom. The extracted crude ethyl bromide is transported by the delivery pump 29 14 and enters the refining tower 21 from the middle.

[0107] Step (2), concentration: the acidic wastewater from the top of the water washing extraction tower enters the concentration tower 5 (tower bottom temperature 120°C, pressure 0.005 MPaG, reflux ratio 2), is heated by the steam coil inside the concentration tower, and the generated gas phase is condensed by the concentration tower condenser 6 (temperature 35°C), and the liquid phase is refluxed to the concentration tower reflux tank 7, a part of which is refluxed to the concentration tower 5 through the concentration tower reflux pump 8, and a part is extracted. When the top temperature of the concentration tower is less than 80°C, it is extracted to the azeotrope collection tank. 10 (water: 4.4%wt, ethanol: 95.6%wt), when the tower top temperature is ≥80°C, it is extracted into the recovery water tank 9; the water phase in the recovery water tank 9 is returned to the water washing extraction tower 3 from the bottom, and the alcohol-containing azeotrope in the azeotrope collecting tank 10 is used as the raw material for producing ethyl bromide; the concentrated hydrobromic acid (purity: 50%wt, temperature 120°C, pressure 0.25MPaG) is obtained in the tower kettle of the concentration tower, and the hydrobromic acid is transported to the hydrobromic acid extraction tower 1 through the delivery pump 3 11 for application;

[0108] The sodium bromide solution from the alkali washing extraction tower enters the concentration crystallizer 13, and is concentrated to obtain sodium bromide solid. The aqueous phase produced after concentration enters the water washing extraction tower 3;

[0109] Step (3), refining: the crude bromoethane product extracted from the bottom of the alkali washing extraction tower enters the refining tower 21 (tower bottom operating temperature 90°C, pressure 0.002MPaG, reflux ratio 9) from the bottom, and is steam-heated by the refining tower reboiler 26. The top gas phase is condensed and refluxed into the refining tower reflux tank 23 through the refining tower condenser 22 (temperature 35°C), and a part of it is refluxed into the refining tower through the refining tower reflux pump 24, and a part of it is returned to the water washing extraction tower 1 for application; the bromoethane extracted from the side is cooled by the cooler 25 (temperature 35°C) to obtain the bromoethane product (purity: 99.9%wt, water content: 80PPm, temperature 35°C, pressure 0.25MPaG), and the product yield is 98%. The recombinant components of the tower bottom of the refining tower 21 are transported to the outside through the refining tower tower bottom pump 27.

Claims

1. A brominated alkane continuous distillation device, characterized in that: It includes extraction device and distillation device; The extraction device comprises a hydrobromic acid extraction tower, a water-washing extraction tower and an alkali-washing extraction tower; the hydrobromic acid extraction tower is provided with a high-density material inlet at the top, a low-density material inlet at the bottom, a high-density material outlet at the bottom and a low-density material outlet at the top, the low-density material outlet is higher than the high-density material inlet, and the high-density material outlet is lower than the low-density material inlet; the low-density material outlet or the high-density material outlet of the hydrobromic acid extraction tower is connected to the brominated alkane inlet at the top of the water-washing extraction tower to transport the brominated alkane after extraction and stratification to the water-washing extraction tower; The water-washing extraction tower is provided with a water inlet at the bottom, a brominated alkane outlet at the bottom, and a water outlet at the top. The brominated alkane inlet is lower than the water outlet, and the brominated alkane outlet is lower than the water inlet. The brominated alkane outlet of the water-washing extraction tower is connected to the brominated alkane inlet at the top of the alkali-washing extraction tower. The alkali-washing extraction tower is provided with an alkali solution inlet at the bottom, a brominated alkane outlet at the bottom, and a salt solution outlet and a gas outlet at the top. The brominated alkane inlet is lower than the salt solution outlet, and the brominated alkane outlet is lower than the alkali solution inlet. The brominated alkane outlet of the alkali-washing extraction tower is connected to the inlet of the rectification device. The distillation device is a double-tower distillation equipment, including a light-removing tower and a refining tower; the inlet of the light-removing tower is connected to the brominated alkane outlet at the bottom of the alkali washing extraction tower, the light-removing tower is equipped with a light-removing tower reboiler, the gas phase outlet at the top of the light-removing tower is connected to the air inlet of the light-removing tower condenser, the liquid outlet of the light-removing tower condenser is connected to the inlet of the light-removing tower reflux tank, and the outlet of the light-removing tower reflux tank is respectively connected to the reflux port at the top of the light-removing tower and the water inlet of the water washing extraction tower; the bottom outlet of the light-removing tower is connected to the inlet of the middle part of the refining tower; the refining tower is equipped with a refining tower reboiler, the gas phase outlet at the top of the refining tower is connected to the air inlet of the refining tower condenser, the liquid outlet of the refining tower condenser is connected to the inlet of the refining tower reflux tank, the outlet of the refining tower reflux tank is respectively connected to the reflux port at the top of the refining tower and the inlet of the product cooler, and the brominated alkane product is extracted at the outlet of the product condenser; Or the distillation device is a single-tower separation device, including a refining tower; the lower inlet of the refining tower is connected to the brominated alkane outlet at the bottom of the alkali washing extraction tower, the refining tower is equipped with a refining tower reboiler, the gas phase outlet at the top of the refining tower is connected to the air inlet of the refining tower condenser, the liquid outlet of the refining tower condenser is connected to the inlet of the refining tower reflux tank, and the outlet of the refining tower reflux tank is respectively connected to the reflux port at the top of the refining tower and the water inlet of the water washing extraction tower; the middle discharge port of the refining tower is connected to the inlet of the product condenser, and the brominated alkane product is extracted at the outlet of the product condenser.

2. The continuous distillation equipment for bromoalkanes according to claim 1, characterized in that: In the hydrobromic acid extraction tower, the low-density material outlet is 0.2 to 3 m higher than the high-density material inlet, and the high-density material outlet is 0.2 to 3 m lower than the low-density material inlet; In the water-wash extraction tower, the bromoalkane inlet is 0.2 to 4 m lower than the water outlet, and the bromoalkane outlet is 0.2 to 4 m lower than the water inlet; In the alkali washing extraction tower, the inlet of the brominated alkane is 0.2 to 3.5 m lower than the outlet of the salt solution, and the outlet of the brominated alkane is 0.2 to 3.5 m lower than the inlet of the alkali solution.

3. The continuous distillation equipment for bromoalkane according to claim 2, characterized in that: In the hydrobromic acid extraction tower, the low-density material outlet is 0.5 to 1.5 m higher than the high-density material inlet, and the high-density material outlet is 0.5 to 1.5 m lower than the low-density material inlet; In the water-wash extraction tower, the bromoalkane inlet is 0.5 to 2 m lower than the water outlet, and the bromoalkane outlet is 0.5 to 2 m lower than the water inlet; In the alkali washing extraction tower, the inlet of the brominated alkane is 0.5 to 2 m lower than the outlet of the salt solution, and the outlet of the brominated alkane is 0.5 to 2 m lower than the inlet of the alkali solution.

4. The continuous distillation equipment for bromoalkanes according to claim 1, characterized in that: The hydrobromic acid extraction tower is a rotary disk extraction tower, a packed extraction tower, a pulse extraction tower or a centrifugal extractor; the water washing extraction tower is a rotary disk extraction tower, a packed extraction tower, a pulse extraction tower or a centrifugal extractor; the alkali washing extraction tower is a rotary disk extraction tower, a packed extraction tower, a pulse extraction tower or a centrifugal extractor.

5. The continuous distillation equipment for bromoalkanes according to claim 4, characterized in that: The turntable extraction tower comprises a middle cylinder, and an upper liquid separation chamber and a lower liquid separation chamber are respectively arranged at the upper and lower ends of the cylinder. The turntable extraction tower is provided with a plurality of sieve plates, a stirring shaft, and a turntable. The sieve plate is an annular sieve plate, and the sieve plate is fixed on the inner wall of the cylinder. The stirring shaft is inserted into the cylinder from the upper liquid separation chamber. A turntable is installed between two adjacent sieve plates, and the turntable is fixed by the stirring shaft and driven to rotate by the stirring shaft. The turntable and the sieve plate only exist in the cylinder, and the upper and lower liquid separation chambers are not provided with turntables and sieve plates.

6. The continuous distillation equipment for bromoalkanes according to claim 1, characterized in that: Also includes: A concentrating device; the concentrating device comprises a concentrating tower, a concentrating tower condenser, a concentrating tower reflux tank, a water recovery tank, an azeotrope collecting tank, and a concentrating crystallizer; the lower inlet of the concentrating tower is connected to the water outlet of the water washing extraction tower, the top gas phase outlet of the concentrating tower is connected to the air inlet of the concentrating tower condenser, the liquid outlet of the concentrating tower condenser is connected to the inlet of the concentrating tower reflux tank, and the outlet of the concentrating tower reflux tank is respectively connected to the reflux port at the top of the concentrating tower, the water recovery tank, and the azeotrope collecting tank; the bottom liquid outlet of the concentrating tower is connected to the high-density material inlet or the low-density material inlet of the hydrobromic acid extraction tower to pass the hydrobromic acid into the hydrobromic acid extraction tower for reuse; the concentrating crystallizer is connected to the salt solution outlet at the top of the alkali washing extraction tower, and the liquid outlet of the concentrating crystallizer is connected to the water inlet of the water washing extraction tower.

7. A continuous distillation process for brominated alkanes based on the continuous distillation equipment for brominated alkanes according to claim 1, characterized in that: The following steps are involved: Step (1), three-stage extraction: according to the different densities of hydrobromic acid and bromoalkane, a high-density material is introduced from the high-density material inlet at the top of the hydrobromic acid extraction tower, and a low-density material is introduced from the low-density material inlet at the bottom, and the alcohol substances in the reaction liquid of the raw material bromoalkane are extracted by hydrobromic acid in the hydrobromic acid extraction tower, and the bromoalkane and the hydrobromic acid are allowed to stand and separate at the top and bottom, and the low-density material after extraction and separation is discharged from the low-density material outlet at the top, and the high-density material after extraction and separation is discharged from the high-density material outlet at the bottom; The brominated alkanes produced by the hydrobromic acid extraction tower enter the water-washing extraction tower from the top, and water enters the water-washing extraction tower from the bottom. In the water-washing extraction tower, water extracts alcohol substances and hydrobromic acid in the brominated alkanes. The brominated alkanes and acidic wastewater are allowed to stand and separate at the top and bottom. The acidic wastewater is produced from the top to the concentration tower, and the brominated alkanes are produced from the bottom. The brominated alkanes produced by the water-washing extraction tower enter the alkali-washing extraction tower from the top, and the alkali solution enters the bottom of the alkali-washing extraction tower from the bottom. In the alkali-washing extraction tower, the acidic substances in the brominated alkanes react with the alkali to generate bromide salts. The brominated alkanes and the aqueous phase containing the bromide salts are allowed to stand and separate at the top and bottom. The bromide salt solution is produced from the top, and the brominated alkanes are produced from the bottom of the alkali-washing extraction tower and enter the rectification device. Step (2), refining: when the distillation device is a double-tower distillation device, the brominated alkanes from the bottom of the alkali-washing extraction tower enter the lightness removal tower, the top gas phase is condensed and refluxed into the reflux tank of the lightness removal tower through the condenser of the lightness removal tower, a part of which is refluxed into the tower, and a part is returned to the water-washing extraction tower for reuse, the brominated alkanes in the tower kettle enter the refining tower, the top gas phase is condensed and refluxed into the reflux tank of the refining tower through the condenser of the refining tower, a part of which is refluxed into the tower, a part of which is extracted, and cooled in a product cooler to obtain a brominated alkanes product; When the distillation device is a single-tower distillation equipment, the brominated alkanes from the bottom of the alkali washing extraction tower enter the refining tower, and the top gas phase is condensed by the refining tower condenser and refluxed into the refining tower reflux tank, a part of which is refluxed into the tower, and a part is returned to the water washing extraction tower for reuse, and the brominated alkanes are extracted from the middle of the refining tower and cooled in the product cooler to obtain the brominated alkanes product.

8. The continuous distillation process for bromoalkanes according to claim 7, characterized in that: In step (1), the bromoalkane reaction liquid is an organic phase of a raw material alcohol and water corresponding to one selected from ethyl bromide, propyl bromide, isobromopropane, butyl bromide, or synthetic ethyl bromide, propyl bromide, isobromopropane, and butyl bromide; the content of bromoalkane in the bromoalkane reaction liquid is not less than the content of bromoalkane in the azeotrope; The concentration of the hydrobromic acid is ≥20%wt; The amount of hydrobromic acid added is the theoretical amount of hydrobromic acid required to produce the brominated alkanes in the brominated alkanes reaction solution, calculated on the basis of the solute HBr; The working temperature of the hydrobromic acid extraction tower is 25°C ± 5°C, and the working pressure is normal pressure; The working temperature of the water washing extraction tower is 25°C ± 5°C, and the working pressure is normal pressure; The ratio of the mass flow rate of the brominated alkane to the mass flow rate of water is 5:1 to 50:1; The working temperature of the alkali washing extraction tower is 20-35°C, and the working pressure is normal pressure-0.002MPaG; The alkali solution is one of sodium bicarbonate solution, potassium bicarbonate solution, lithium bicarbonate solution, sodium hydroxide solution and potassium hydroxide solution; the concentration of the alkali solution is ≥5%wt; The amount of alkali solution added is to control the pH of the aqueous phase of the alkali washing extraction tower to be 7-10.

9. The continuous distillation process for bromoalkanes according to claim 7 or 8, characterized in that: In step (1), the purity of the brominated alkane in the brominated alkane reaction solution is ≥80%wt; the concentration of the hydrobromic acid is 50%wt; The ratio of the mass flow rate of the brominated alkane to the mass flow rate of water is 10:1 to 40:1; The alkali solution is a sodium bicarbonate solution; The amount of alkali solution added is to control the pH of the aqueous phase of the alkali washing extraction tower to be 7.5-8.

10. The continuous distillation process for bromoalkanes according to claim 7, characterized in that: In step (2), the lightness removal tower and the refining tower are packed towers, and the packing is BX, CY wire mesh packing, 125X, 125Y, 250X, 250Y, 350X, 350Y, 450X, 450Y, 500X, 500Y, 700X, 700Y, 750X or 750Y plate corrugated packing; When the distillation device is a double-tower distillation device, the pressure of the lightness removal tower is 0-0.1 MPaG, the operating temperature of the tower bottom is 80-110°C, and the reflux ratio is 5-10; the pressure of the refining tower is 0-0.1 MPaG, the operating temperature of the tower bottom is 90-120°C, and the reflux ratio is 2-10; The temperature of the lightness removal tower condenser is 30-70°C; When the distillation device is a double-tower distillation device, the temperature of the distillation tower condenser is 30-70°C; When the distillation device is a single-tower distillation device, the pressure of the refining tower is 0-0.1 MPaG, the operating temperature of the tower bottom is 90-120°C, and the reflux ratio is 3-10; When the distillation device is a single-tower distillation device, the temperature of the distillation tower condenser is 30-70°C; The temperature of the product cooler is 30-60°C.

11. The continuous distillation process for bromoalkanes according to claim 10, characterized in that: In step (2), the lightness removal tower and the refining tower are packed towers, and the packing is 125X, 125Y, 250X, 250Y, 350X, 350Y, 450X, 450Y, 500X or 500Y plate corrugated packing; When the distillation device is a double-tower distillation device, the pressure of the lightness removal tower is 0-10KPaG, the operating temperature of the tower bottom is 90-100°C, and the reflux ratio is 7-9; the pressure of the refining tower is 0-10KPaG, the operating temperature of the tower bottom is 95-110°C, and the reflux ratio is 5-8; The temperature of the light removal tower condenser is 35-50°C; When the distillation device is a double-tower distillation device, the temperature of the distillation tower condenser is 35-50°C; When the distillation device is a single-tower distillation device, the pressure of the refining tower is 0-10KPaG, the operating temperature of the tower bottom is 95-110°C, and the reflux ratio is 6-9; When the distillation device is a single-tower distillation device, the temperature of the distillation tower condenser is 35-50°C; The temperature of the product cooler is 35-40°C.

12. The continuous distillation process for bromoalkanes according to claim 7, characterized in that: The method comprises the following steps: (3) concentration: acid wastewater from the top of the water-washing extraction tower enters the concentration tower, the generated gas phase is condensed by the concentration tower condenser, the liquid phase is refluxed to the concentration tower reflux tank, a part of which is refluxed to the concentration tower, and a part of which is respectively extracted to a recovery water tank and an azeotrope collecting tank according to different extraction temperatures; the water phase in the recovery water tank is returned to the water-washing extraction tower, the alcohol-containing azeotrope in the azeotrope collecting tank is used as a bromoalkane reaction raw material, the tower kettle is the hydrobromic acid obtained by concentration, and is returned to the hydrobromic acid extraction tower for reuse; the bromide salt solution from the alkali-washing extraction tower enters the concentration crystallizer for concentration and crystallization to obtain bromide salt solid, and the water phase generated by the concentration and crystallization enters the water-washing extraction tower.

13. The continuous distillation process for bromoalkanes according to claim 12, characterized in that: In step (3), the concentration tower is a packed tower, and the packing is BX, CY wire mesh packing, 125X, 125Y, 250X, 250Y, 350X, 350Y, 450X, 450Y, 500X, 500Y, 700X, 700Y, 750X or 750Y plate corrugated packing; The pressure of the concentration tower is 0-0.1 MPaG, the operating temperature of the tower bottom is 110-140°C, and the reflux ratio is 1-10; The temperature of the concentration tower condenser is 45-70°C; When the top temperature of the concentrator is less than the azeotropic point, the gas phase produced by the concentrator is condensed by the concentrator condenser, and the liquid phase is refluxed to the reflux tank of the concentrator, part of which is refluxed to the concentrator, and part is extracted to the azeotropic collection tank; When the top temperature of the concentration tower is ≥ the azeotropic point, the gas phase produced by the concentration tower is condensed through the concentration tower condenser, and the liquid phase refluxes to the concentration tower reflux tank, part of which refluxes to the concentration tower and part is extracted to the recovery water tank.

14. The continuous distillation process for bromoalkanes according to claim 13, characterized in that: In step (3), the concentration tower is a packed tower, and the packing is 125X, 125Y, 250X, 250Y, 350X, 350Y, 450X, 450Y, 500X or 500Y plate corrugated packing or; The pressure of the concentration tower is 0-10KPaG, the operating temperature of the tower bottom is 120-130°C, and the reflux ratio is 2-5; The temperature of the concentration tower condenser is 50-65°C.

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