A method for treating a crystallization mother liquor in a separation system for bromine-containing organic substances

Abstract

This invention discloses a method for treating the mother liquor from crystallization in a bromine-containing organic matter separation system, belonging to the field of recrystallization solvent recovery and treatment technology. The method includes: the mother liquor is preheated and then enters an evaporator; a portion of the recrystallization solvent is distilled off from the top of the evaporator, condensed, collected, and recycled; the residual liquid at the bottom of the evaporator is preheated and, together with hot air from a hot air system, is introduced into a dryer under controlled vacuum conditions; the remaining recrystallization solvent is distilled off from the top of the dryer, condensed, collected, and recycled; the hot air is processed in a hot air system and then re-enters the dryer for circulation; the bromine-containing organic mixture powder is discharged from the bottom of the dryer for solid waste treatment. This application, by coupling the evaporator and the dryer and controlling the structure and operating conditions of the evaporator, significantly improves the solvent removal rate, reduces the energy consumption for residual liquid treatment in the bromine-containing solid waste separation system, and improves treatment efficiency.

Description

Technical Field

[0001] This invention relates to the field of recrystallization solvent recovery and treatment technology, and in particular to a method for treating the mother liquor of crystallization in a bromine-containing organic separation system. Background Technology

[0002] Flame retardants play a crucial role in the development of many fields, including electronics, building energy conservation, modern transportation, and power grid construction, and are indispensable materials. In recent years, despite environmental safety concerns, brominated flame retardants have become an important category supporting the development of my country's modern manufacturing industry due to their high flame retardant efficiency, long-lasting application stability, and excellent electrical properties. Among various brominated flame retardants, tetrabromobisphenol A and tribromophenol are the most widely used. They can be used as reactive and additive flame retardants, as well as as intermediates for synthesizing higher molecular weight and higher performance brominated flame retardant products.

[0003] Currently, the synthesis of tetrabromobisphenol A mainly uses bisphenol A as a raw material, which is produced by the oxidation reaction of bromine with hydrogen peroxide in chlorobenzene solvent. This reaction process is prone to side reactions, producing other bromine-containing impurities. In actual industrial production processes, recrystallization is often used to improve the purity of tribromophenol and tetrabromobisphenol A products to obtain higher purity products. After repeated recycling, the content of impurities (such as bisphenol A, 2,4-dibromophenol, 2,6-dibromophenol, etc.) in the recrystallization mother liquor increases significantly, requiring the recovery and recycling of the recrystallization solvent. The solvent content in the recrystallization mother liquor is high (approximately 90 wt%). Currently, distillation is commonly used to treat the mother liquor, but distillation has problems such as high energy consumption and incomplete solvent recovery. In particular, as the solvent recovery rate increases, the bottom temperature of the reactor continuously rises, and tribromophenol and tetrabromobisphenol A decompose and deteriorate at high temperatures, thus affecting the quality of tribromophenol and tetrabromobisphenol A. In addition, bromine-containing organic compounds such as tribromophenol and tetrabromobisphenol A have high freezing points (tribromophenol has a freezing point of 90℃ and tetrabromobisphenol A has a freezing point of 180℃). When using distillation to recover the crystallization mother liquor, the equipment is prone to blockage, resulting in low overall recovery efficiency.

[0004] Tetrabromobisphenol A and tribromophenol are major brominated flame retardants, and their efficient recycling has significant social and economic benefits. Therefore, there is an urgent need to develop a crystallization mother liquor recovery device and method with high recovery efficiency and low energy consumption. In view of this, this application is hereby submitted. Summary of the Invention

[0005] The purpose of this invention is to provide an apparatus and method for treating crystallization mother liquor in a bromine-containing organic matter separation system. By coupling an evaporator and a dryer, and controlling the structure and operating conditions of the evaporator, the solvent removal rate is significantly improved, the energy consumption for residual liquid treatment in the bromine-containing solid waste separation system is reduced, and the treatment efficiency is increased.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides an apparatus for processing crystallization mother liquor in a bromine-containing organic separation system, comprising a first preheater, an evaporator, a second preheater, a dryer, a first cooler, a second cooler, and a hot air system; The outlet of the first preheater is connected to the inlet of the evaporator, the upper outlet of the evaporator is connected to the first cooler, the lower outlet of the evaporator is connected to the second preheater, the outlet of the second preheater is connected to the inlet of the dryer, the upper outlet of the dryer is connected to the second cooler, the inlet of the hot air system is connected to the second cooler, and the outlet of the hot air system is connected to the dryer.

[0007] Preferably, the evaporator is a scraped thin-film evaporator.

[0008] Preferably, the dryer is a spray drying tower.

[0009] Secondly, the present invention also provides a method for treating the mother liquor of a bromine-containing organic matter separation system based on the above-mentioned apparatus, comprising the following steps: S1. After preheating, the crystallization mother liquor enters the evaporator. Part of the recrystallization solvent is evaporated from the top of the evaporator, collected after condensation, and recycled. Furthermore, the evaporator is a scraped-film evaporator.

[0010] S2. The residual liquid at the bottom of the evaporator is preheated and then introduced into the dryer along with the hot air from the hot air system. Vacuum operating conditions are controlled. The remaining recrystallization solvent evaporates from the top of the dryer, is collected after condensation, and is recycled. The hot air is processed by the hot air system and then re-enters the dryer for circulation. The bromine-containing organic mixture powder is discharged from the bottom of the dryer for solid waste treatment. Further, the dryer is a spray drying tower.

[0011] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) The thin film evaporator and spray drying tower are coupled, and the vacuum operation is adopted. The structure and operating conditions of the evaporator are controlled, the solvent removal rate exceeds 99%, and the solvent recycling rate is high. (2) The method of this application is simple and can be operated continuously and stably, which significantly reduces the energy consumption of residual liquid treatment in the bromine-containing solid waste separation system and improves the treatment efficiency.

[0012] Other features and advantages of the invention will become clear from the following detailed description of exemplary embodiments of the invention with reference to the accompanying drawings. Attached Figure Description

[0013] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments of the invention and, together with their description, serve to explain the principles of the invention.

[0014] Figure 1 This is a schematic diagram of the device structure for treating the mother liquor of crystallization in the separation system for bromine-containing organic compounds according to the present invention; Figure 2 This is a schematic diagram of the evaporator structure of the present invention; Figure 3 for Figure 2 A schematic diagram of the horizontal cross-section of the distributor 210; Figure 4 This is a schematic diagram of the dryer of the present invention; Figure 5 for Figure 4 A schematic diagram of the horizontal cross-section at nozzle 502 in the medium series.

[0015] Explanation of reference numerals in the attached figures: 1. First preheater; 2. Evaporator; 201. Cylinder; 202. Demister; 203. Material inlet; 204. Scraper; 205. Heating jacket; 206. Heat medium inlet; 207. Transmission device; 208. Gas outlet; 209. Shaft; 210. Distributor; 2101. Spiral flow channel; 2102. Vent; 211. Heat medium outlet; 212. Residual liquid outlet; 3. First cooler; 4. Second preheater; 5. Dryer; 501. Spray drying tower body; 502. Series nozzles; 503. Gas distributor; 504. Hot gas inlet; 505. Solvent outlet; 506. Cyclone separator; 507. Discharge port; 508. Solid outlet; 6. Second cooler; 7. Hot air system. Detailed Implementation

[0016] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention.

[0017] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the invention or its application or use.

[0018] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, they should be considered part of the specification.

[0019] In all the examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0020] It should be noted that similar labels and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be discussed further in subsequent figures.

[0021] The operating pressure mentioned in the following examples refers to absolute pressure, and the unit is kPa (A).

[0022] like Figure 1 As shown, this embodiment of an apparatus for treating crystallization mother liquor in a bromine-containing organic matter separation system includes a first preheater 1, an evaporator 2, a second preheater 4, a dryer 5, a first cooler 3, a second cooler 6, and a hot air system 7. The outlet of the first preheater 1 is connected to the inlet of the evaporator 2, the upper outlet of the evaporator 2 is connected to the first cooler 3, the lower outlet of the evaporator 2 is connected to the second preheater 4, the outlet of the second preheater 4 is connected to the inlet of the dryer 5, the upper outlet of the dryer 5 is connected to the second cooler 6, the inlet of the hot air system 7 is connected to the second cooler 6, and the outlet of the hot air system 7 is connected to the dryer 5.

[0023] In some preferred embodiments, the evaporator 2 is a scraped thin-film evaporator.

[0024] In some implementations, such as Figure 2 As shown, the scraped film evaporator includes a transmission device 207, a separation unit, an evaporation unit, and a discharge unit; the shaft 209 of the transmission device 207 is located at the center of the cylinder 201 of the scraped film evaporator; the separation unit is a demister 202, located at the upper part of the cylinder 201; the evaporation unit includes a material inlet 203, a distributor 210, a scraper 204, and a heating jacket 205; the discharge unit includes a gas outlet 208 and a residual liquid outlet 212. The material inlet 203 is located below the demister 202; the distributor 210 is connected to the shaft 209 of the transmission device and is located below the material inlet 203; the scraper 204 is connected to the shaft 209 of the transmission device and is located below the distributor 210, and the scraper 204 is a sliding scraper; the heating jacket 205 is located at the lower part of the cylinder 201 and distributed on the outer periphery, the lower part of the heating jacket 205 is provided with a heat medium inlet 206, and the upper part of the heating jacket 205 is provided with a heat medium outlet 211; the gas outlet 208 is located at the top of the cylinder, and the residual liquid outlet 212 is located at the bottom of the cylinder.

[0025] In some preferred embodiments, the distributor 210 is a semi-enclosed structure without a top cover, such as... Figure 3 As shown, a spiral flow channel 2101 is opened on the surface, and the direction of the spiral flow channel 2101 is consistent with the rotation direction of the shaft 209; a series of vent holes 2102 are arranged at the bottom of the distributor 210, the diameter of the vent holes 2102 is 4-10mm, and the opening rate is 50-70%.

[0026] Existing technologies typically design distributors as fully enclosed structures, with liquid redistributed inside the distributor and gas passing through the sides or gaps in the middle of the distributor. This design easily leads to gas short-circuiting and affects liquid distribution. In contrast, the distributor 210 of the scraped-film evaporator in this application is a semi-enclosed structure without a top cover, featuring spiral flow channels 2102 on its surface and a series of vents 2102 at the bottom. The height of the spiral flow channels 2102 is determined by the throughput to ensure a certain amount of material is stored. Furthermore, this application directly collects and redistributes the liquid from the demister, and the gas is evenly dispersed through the vents 2102 at the bottom of the distributor 210, improving gas-liquid separation and increasing evaporation efficiency.

[0027] In some preferred embodiments, the dryer 5 is a spray drying tower.

[0028] In some implementations, such as Figure 4 As shown, the spray drying tower includes a feeding system, a separation system, and a discharge system. The feeding system includes a liquid feeding system and a gas feeding system; the separation system includes a cyclone separator 506 located at the top of the spray drying tower body 501; the discharge system includes a solvent outlet 505, a discharge port 507, and a solids outlet 508.

[0029] The liquid feeding system includes a series of nozzles 502 evenly arranged circumferentially along the body 501 of the spray drying tower, located in the middle or lower part of the body 501 of the spray drying tower. Figure 5 As shown; the gas feeding system includes a gas distributor 503 located inside the lower part of the spray drying tower body 501 and a hot gas inlet 504 located at the bottom of the spray drying tower body 501; the solvent outlet 505 is located at the top of the spray drying tower body 501, the discharge port 507 is located on the side of the conical bottom of the spray drying tower body 501, and the solid outlet 508 is located at the bottom of the spray drying tower body 501.

[0030] In some preferred embodiments, the series nozzles 502 are pressure nozzles, with the spray direction at 0-5° to the horizontal plane. The number of nozzles depends on the throughput. The series nozzles 502 break the bromine-containing residue from the previous process into micron-sized droplets, enhancing heat transfer and improving solvent removal efficiency.

[0031] In some alternative embodiments, the gas distributor 503 is one of a tubular gas distributor, a trough gas distributor, or a perforated plate gas distributor; the hot gas is evenly distributed after passing through the gas distributor 503, which improves the efficiency of droplet drying and the solid particles after fluidized drying, and prevents bottom blockage.

[0032] In some implementations, the cyclone separator 506 is configured with one or more sets depending on the throughput.

[0033] Existing technologies typically configure the feeding system as a top-down spray system with the gas outlet at the bottom and the cyclone separator externally mounted. This design suffers from problems such as large footprint and low separation efficiency of dried particles and fluidized gas. In contrast, the material feeding system in this application is designed with a series of circumferentially evenly arranged nozzles 502 for spraying; the solvent gas outlet is located at the top; and the cyclone separator is built into the spray drying tower. This reduces the footprint, and the gas and solids are discharged independently from the top and bottom, respectively, without interference, thus improving gas-solid separation efficiency.

[0034] Based on the above apparatus, the method for treating the crystallization mother liquor in the bromine-containing organic matter separation system of this embodiment includes the following steps: S1. After preheating, the crystallization mother liquor enters evaporator 2. Part of the recrystallization solvent is evaporated from the top of evaporator 2, condensed and collected by the first cooler 3, and then recycled. The residual liquid at the bottom of evaporator 2 includes bromine-containing organic compounds rich in tribromophenol and tetrabromobisphenol A.

[0035] In some embodiments, the crystallization mother liquor comprises, by weight, 60-90 parts chlorobenzene; 5-15 parts tribromophenol; 3-15 parts tetrabromobisphenol A; and approximately 2-10 parts of bisphenol A, 2,4-dibromophenol, and 2,6-dibromophenol.

[0036] In some embodiments, the temperature of the preheated crystallization mother liquor is 70-80°C.

[0037] In some embodiments, the evaporator 2 is a scraped-film evaporator with an operating pressure of 10-50 kPa(A) and an operating temperature of 70-80°C. Bromine-containing organic compounds have high freezing points; if all the recrystallization solvent is evaporated, the residual liquid is prone to solidification, affecting normal continuous operation. The evaporation temperature is controlled by utilizing the difference in solubility between the recrystallization solvent and the bromine-containing organic compound at different temperatures, thereby controlling the solvent content to form a saturated mixed solution of the bromine-containing organic compound and the recrystallization solvent. In some preferred embodiments, after the recrystallization solvent is removed by the scraped-film evaporator, the recrystallization solvent content in the residual liquid at the bottom of the scraped-film evaporator is controlled at 10-15 wt%.

[0038] In some embodiments, the crystallization mother liquor, heated by the first preheater 1, is introduced through the material inlet 203. The material falls into the central region of the distributor 210 and is evenly sprayed onto the inner wall of the cylinder 201 along the spiral flow channel 2101 under centrifugal force. Under gravity, the material flows downward along the inner wall and is scraped into a turbulent film of 0.5-2 mm by the scraper 204, flowing naturally downward. The heat medium indirectly transfers heat to the film through the heating jacket 205. The light component solvent in the material is evaporated into gas and flows upward. The gas passes through the vent 2102 of the distributor 210 and enters the demister 202 for gas-liquid separation. The gas flows out from the top gas outlet 208 and enters the next process; the liquid falls back into the distributor 210. The remaining bromine-containing organic compounds in the material, rich in tribromophenol and tetrabromobisphenol A, flow out as residual liquid from the bottom residual liquid outlet 212 and enter the next process.

[0039] S2. The residual liquid at the bottom of the evaporator 2 is preheated by the second preheater 4 and then introduced into the dryer 5 along with the hot air from the hot air system 7. The vacuum operating conditions are controlled. The remaining recrystallization solvent is evaporated from the top of the dryer 5, condensed and collected by the second cooler 6, and then recycled. The hot air enters the hot air system 7 for treatment and then re-enters the dryer 5 for circulation. The bromine-containing organic mixture powder is discharged from the bottom of the dryer 5 for solid waste treatment.

[0040] In some embodiments, the temperature of the residual liquid at the bottom of the evaporator 2 (i.e., the scraped film evaporator) after preheating by the second preheater 4 is 80-90°C.

[0041] In some embodiments, the dryer 5 is a spray drying tower with an operating pressure of 5-10 kPa(A) and an operating temperature of 60-80°C.

[0042] In some embodiments, the bottom residual liquid is sprayed into the main body of the spray drying tower at a spray velocity of 50-80 m / s and atomized into micron-sized droplets for drying.

[0043] In some preferred embodiments, the direction of the spray is at 0-5° to the horizontal plane.

[0044] In some alternative embodiments, the hot air medium of the hot air system is either air or nitrogen.

[0045] The working principle of the spray drying tower is as follows: the remaining bromine-containing organic residue rich in tribromophenol and tetrabromobisphenol A from the scraped film evaporator outlet 212 is sprayed into the spray drying tower body 501 through a series of nozzles 502, atomizing into micron-sized droplets. Preheated hot air enters the spray drying tower body 502 from the gas feed system. Under the action of the hot air, the droplets lose solvent, forming solvent vapor and solid powder. These are separated by a cyclone separator 506. The solvent vapor and hot air are discharged from the top of the solvent outlet 505 and proceed to the next process; the solid powder falls along the feed leg of the cyclone separator 506 and is discharged from the solid outlet 508, proceeding to the next process.

[0046] Example 1 The method for treating the crystallization mother liquor in a bromine-containing organic matter separation system using the apparatus of this application, which couples a scraped-film evaporator and a spray drying tower, is as follows: The crystallization mother liquor, comprising 80g chlorobenzene, 10g tribromophenol, 5g tetrabromobisphenol A, 0.5g bisphenol A, 3g 2,4-dibromophenol, and 3g 2,6-dibromophenol, is preheated to 75°C and then added to the scraped-film evaporator. The operating pressure is controlled at 20kPa(A), and the operating temperature at 75°C. Part of the recrystallization solvent is distilled off from the top of the scraped-film evaporator, collected after condensation, and recycled. At this point, the residual liquid at the bottom of the scraped-film evaporator contains bromine-containing organic compounds rich in tribromophenol and tetrabromobisphenol A, and the recrystallization solvent content is 12 wt%. The residual liquid at the bottom was preheated to 85°C and introduced into the spray drying tower along with hot air. The operating pressure was controlled at 8 kPa(A) and the operating temperature at 70°C. The remaining recrystallization solvent was distilled off from the top of the spray drying tower, collected after condensation, and recycled. The hot air was treated in the hot air system 7 and then recirculated into the spray drying tower. The bromine-containing organic mixture powder was discharged from the bottom of the spray drying tower for solid waste treatment. The solvent removal rate was measured to be 99.7%.

[0047] Example 2 The method for treating the crystallization mother liquor in a bromine-containing organic matter separation system using the apparatus of this application, which couples a scraped-film evaporator and a spray drying tower, is as follows: The crystallization mother liquor, comprising 70g chlorobenzene, 15g tribromophenol, 10g tetrabromobisphenol A, 1g bisphenol A, 2g 2,4-dibromophenol, and 2g 2,6-dibromophenol, is preheated to 80°C and then added to the scraped-film evaporator. The operating pressure is controlled at 40kPa(A), and the operating temperature at 80°C. Part of the recrystallization solvent is distilled off from the top of the scraped-film evaporator, collected after condensation, and recycled. At this point, the residual liquid at the bottom of the scraped-film evaporator contains bromine-containing organic compounds rich in tribromophenol and tetrabromobisphenol A, and the recrystallization solvent content is 10 wt%. The residual liquid at the bottom was preheated to 90°C and introduced into the spray drying tower along with hot air. The operating pressure was controlled at 5 kPa(A) and the operating temperature at 80°C. The remaining recrystallization solvent was distilled off from the top of the spray drying tower, collected after condensation, and recycled. The hot air was treated in the hot air system 7 and then recirculated into the spray drying tower. The bromine-containing organic mixture powder was discharged from the bottom of the spray drying tower for solid waste treatment. The solvent removal rate was measured to be 99.4%.

[0048] Example 3 The method for treating the crystallization mother liquor in a bromine-containing organic matter separation system using the apparatus of this application, which couples a scraped-film evaporator and a spray drying tower, is as follows: The crystallization mother liquor, comprising 90g chlorobenzene, 5g tribromophenol, 3g tetrabromobisphenol A, 0.5g bisphenol A, 1g 2,4-dibromophenol, and 1g 2,6-dibromophenol, is preheated to 70°C and then added to the scraped-film evaporator. The operating pressure is controlled at 10kPa(A), and the operating temperature at 70°C. Part of the recrystallization solvent is distilled off from the top of the scraped-film evaporator, collected after condensation, and recycled. At this point, the residual liquid at the bottom of the scraped-film evaporator contains bromine-containing organic compounds rich in tribromophenol and tetrabromobisphenol A, and the recrystallization solvent content is 15wt%. The residual liquid at the bottom was preheated to 80°C and introduced into the spray drying tower along with hot air. The operating pressure was controlled at 10 kPa(A) and the operating temperature at 60°C. The remaining recrystallization solvent was distilled off from the top of the spray drying tower, collected after condensation, and recycled. The hot air was treated in the hot air system 7 and then recirculated into the spray drying tower. The bromine-containing organic mixture powder was discharged from the bottom of the spray drying tower for solid waste treatment. The solvent removal rate was measured to be 99.0%.

[0049] Comparative Example 1 The difference from Example 1 is that the scraped-film evaporator of this application is replaced with an existing evaporator, whose distributor is a fully enclosed structure and lacks the spiral flow channel and vent design of this application. The solvent removal rate was measured to be 93.2%.

[0050] Comparative Example 2 The difference from Example 1 is that the spray drying tower of this application is replaced with an existing dryer, whose feeding system is top-down spraying, the gas outlet is located at the bottom, and the cyclone separator is externally mounted. The solvent removal rate was measured to be 95.9%.

[0051] Comparative Example 3 The difference from Example 1 is that the operating temperature of the scraped thin film evaporator is set to 95°C, which is higher than the freezing point of bromine-containing organic matter. Residual liquid solidifies at the bottom, and the solvent removal rate is measured to be 93.5%.

[0052] While specific embodiments of the invention have been described in detail by way of examples, those skilled in the art should understand that the examples are for illustrative purposes only and not intended to limit the scope of the invention. Those skilled in the art should understand that modifications can be made to the above embodiments without departing from the scope and spirit of the invention. The scope of the invention is defined by the appended claims.

Claims

1. A method for treating the mother liquor from crystallization in a bromine-containing organic matter separation system, characterized in that, Includes the following steps: S1. After preheating, the crystallization mother liquor enters the evaporator. Part of the recrystallization solvent evaporates from the top of the evaporator, is collected after condensation, and is recycled. S2. The residual liquid at the bottom of the evaporator is preheated and then introduced into the dryer along with the hot air from the hot air system. The vacuum operating conditions are controlled. The remaining recrystallization solvent is evaporated from the top of the dryer, collected after condensation, and recycled. The hot air is processed by the hot air system and then re-enters the dryer for circulation. The bromine-containing organic mixture powder is discharged from the bottom of the dryer for solid waste treatment.

2. The method for treating the mother liquor of crystallization in a bromine-containing organic matter separation system according to claim 1, characterized in that, According to the mass fraction, the crystallization mother liquor includes 60-90 parts of chlorobenzene; 5-15 parts of tribromophenol; 3-15 parts of tetrabromobisphenol A; and approximately 2-10 parts of bisphenol A, 2,4-dibromophenol, and 2,6-dibromophenol.

3. The method for treating the mother liquor of crystallization in a bromine-containing organic matter separation system according to claim 1, characterized in that, In step S1, the temperature of the preheated crystallization mother liquor is 70-80℃.

4. The method for treating the mother liquor of crystallization in a bromine-containing organic matter separation system according to claim 1, characterized in that, In step S1, the evaporator is a scraped thin-film evaporator with an operating pressure of 10-50 kPa and an operating temperature of 70-80℃.

5. The method for treating the mother liquor of crystallization in a bromine-containing organic matter separation system according to claim 4, characterized in that, In step S1, after the crystallization mother liquor enters the scraped film evaporator, it is evenly sprayed onto the inner wall of the cylinder along the guide channel under the action of centrifugal force. Under the action of gravity, it flows downward and is forcibly scraped into a turbulent film of 0.5-2mm by the scraper for indirect heat transfer evaporation.

6. The method for treating the mother liquor of crystallization in a bromine-containing organic matter separation system according to claim 1, characterized in that, In step S2, the temperature of the residual liquid at the bottom of the scraped thin film evaporator after preheating is 80-90℃.

7. The method for treating the mother liquor of crystallization in a bromine-containing organic matter separation system according to claim 1, characterized in that, In step S2, the dryer is a spray drying tower with an operating pressure of 5-10 kPa and an operating temperature of 60-80℃.

8. The method for treating the mother liquor of crystallization in a bromine-containing organic matter separation system according to claim 7, characterized in that, In step S2, the bottom residual liquid is sprayed into the main body of the spray drying tower at a spray speed of 50-80 m / s and atomized into micron-sized droplets for drying.

9. The method for treating the mother liquor of crystallization in a bromine-containing organic matter separation system according to claim 8, characterized in that, In step S2, the direction of the spray is at a 0-5° angle to the horizontal plane.

10. The method for treating the mother liquor of crystallization in a bromine-containing organic matter separation system according to claim 1, characterized in that, In step S2, the hot air medium of the hot air system is either air or nitrogen.

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