A solvent recovery device for preparing tetrabromobisphenol A

Abstract

The present application relates to the field of solvent recovery, and particularly relates to a solvent recovery device for preparing tetrabromobisphenol A, comprising a bromination unit, an adsorption unit, a neutralization unit and a post-treatment unit connected in series through pipelines. The bromination unit adopts a multi-chamber reactor, which is internally provided with heating pipes, partitions and turnover plates. The intelligent control of bromine addition amount and the reflux of incomplete reaction solvent are realized through sampling detection and a three-way valve. Low brominated bisphenol A is converted into tetrabromobisphenol A, and the crystal is collected. The adsorption unit is provided with a modular adsorption part which can be conveniently replaced. Activated carbon and other adsorbents are used to remove impurities. The neutralization unit realizes the neutralization of residual bromine and acidic substances through alkali injection and stirring. The post-treatment unit separates the space by using a flow guide plate, and then carries out water washing, efficient layering and interface water phase extraction, adsorption drying, and finally obtains pure chlorobenzene solvent. The present application realizes the efficient and continuous recovery of chlorobenzene solvent, simplifies the process, and improves the resource utilization rate.

Description

Technical Field

[0001] This invention relates to the field of solvent recovery, and more particularly to a solvent recovery apparatus for the preparation of tetrabromobisphenol A. Background Technology

[0002] Tetrabromobisphenol A (TBBPA), an important intermediate in brominated flame retardants, is widely used in engineering plastics such as epoxy resins and polycarbonates. In its industrial production, chlorobenzene is typically used as a solvent. After the reaction, the chlorobenzene solvent inevitably contains unreacted low-brominated bisphenol A (such as monobromo, dibromo, and tribromobisphenol A), excess bromine, reaction byproducts, solid particles, and trace amounts of phenolic substances, among other impurities. To reduce production costs and meet environmental requirements, these impurity-containing chlorobenzene solvents must be effectively recovered and purified for recycling.

[0003] Currently, the recovery process of chlorobenzene, the solvent after the preparation of tetrabromobisphenol A, generally adopts filtration and washing, and vacuum distillation. After the reaction is completed, the chlorobenzene phase is filtered to remove solid impurities and washed with deionized water to remove residual salts or by-products. The washed chlorobenzene phase is then subjected to vacuum distillation to first remove water and then distill off chlorobenzene at a specific temperature, thus realizing the recovery and utilization of chlorobenzene.

[0004] The process has the following drawbacks: First, the removal of some low-bromine bisphenol A doped in the solvent by direct water washing is wasteful; second, the vacuum distillation temperature generally exceeds 120°C, which requires a large amount of energy, and the temperature needs to be precisely controlled during the distillation process, making the process complex and difficult to control; third, water washing alone is insufficient to completely remove impurities from chlorobenzene, resulting in some impurities remaining in the chlorobenzene after vacuum distillation, affecting the purity of the chlorobenzene. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a solvent recovery device for preparing tetrabromobisphenol A. This invention achieves efficient and continuous recovery and high-purity regeneration of chlorobenzene solvent, simplifies the process, improves resource utilization, enhances environmental friendliness, and solves the problems of high energy consumption, raw material waste, and low purity in traditional solvent chlorobenzene recovery. Specifically, it is achieved through the following technical solutions.

[0006] This invention discloses a solvent recovery device for the preparation of tetrabromobisphenol A, comprising: (1) a series of pipes connected in series via a pump body.

[0007] The bromination unit has a multi-stage series chamber structure. Each chamber is equipped with a flow-turning plate to extend the solvent flow path and a heating tube to maintain the system temperature of 80℃~95℃. The top of the final chamber is equipped with a sampling tube and a three-way valve to adjust the solvent flow direction according to the detection results of low-brominated bisphenol A content.

[0008] The adsorption unit adopts a radial flow channel structure consisting of a central channel and symmetrical side channels. A replaceable activated carbon adsorption section is set between the channels for dynamic adsorption of bromine and organic impurities.

[0009] The neutralization unit includes a motor-driven rotating shaft and a vessel body, used to add sodium hydroxide reagent into the vessel body to achieve a mixing reaction between sodium hydroxide and residues;

[0010] The post-processing unit is equipped with a water washing zone, a stratification zone, and a drying zone separated by a first guide plate and a second guide plate. A distribution plate is provided at the bottom of the water washing zone to input deionized water into the water washing zone to complete the water washing of the solvent. A distribution pipe is provided at the top of the stratification zone to draw out the upper aqueous phase after the organic phase and aqueous phase are separated. An adsorption layer is built into the drying zone to deeply adsorb residual moisture in the organic phase.

[0011] Preferably, the chambers of the bromination unit are sealed and separated by partitions, and adjacent chambers are connected through a bottom collection section;

[0012] The collection section includes a collection box with a filter screen for trapping and collecting tetrabromobisphenol A crystals. A drain valve is installed at the bottom of the collection box for discharging tetrabromobisphenol A crystals.

[0013] Preferably, the first port of the three-way valve is connected to the outlet pipe via a drive pump, the second port is connected to the pre-stage chamber via a pipeline to achieve reaction recirculation, and the third port is connected to the adsorption unit.

[0014] Preferably, the adsorption section includes an adsorption box with through holes and an activated carbon core. The adsorption box is inserted into the positioning frame, and the side of the positioning frame is provided with a removable sealing baffle to isolate the flow channel.

[0015] Preferably, the first guide plate and the second guide plate are vertically arranged, the first guide plate is fixed to the bottom of the box and forms an overflow channel at the top, and the second guide plate is fixed to the top of the box and forms an organic phase channel at the bottom.

[0016] Preferably, the connection port of the collection box is located between the partition and the flow plate, at the lowest point of the chamber.

[0017] Preferably, the adsorption layer is a filled drying layer composed of anhydrous sodium sulfate.

[0018] Preferably, the positioning frame has a limiting plate on the side near the side channel for engaging the sealing baffle.

[0019] After adopting the above technical solution, the beneficial effects of the present invention are:

[0020] 1. This invention systematically removes solid particles, organic impurities, bromine, acidic substances, salts, and moisture from chlorobenzene solvent through the close synergy of multiple purification steps such as bromination, adsorption, neutralization, water washing, layering, and drying, ultimately obtaining chlorobenzene with high purity, which fully meets the requirements for recycling in the tetrabromobisphenol A preparation process.

[0021] 2. This invention highly integrates multiple previously dispersed processing steps into a continuous flow device system. By connecting the functional units in series through pumps and pipelines, it achieves automated and continuous operation of solvent recovery, simplifies the process, reduces energy consumption and operational complexity, and improves overall production efficiency.

[0022] 3. The bromination unit of this invention adopts a multi-chamber series design, with precise temperature control by heating tubes, extended reaction path by flow-turning plates, and efficient and controllable conversion of low-brominated bisphenol A to tetrabromobisphenol A through sampling detection and intelligent three-way valve control. The collection box and filter screen set at the bottom of each chamber can collect and separate the precipitated tetrabromobisphenol A crystals in a timely manner, which not only improves the additional recovery rate of tetrabromobisphenol A, but also effectively reduces the content of solid phase impurities in subsequent processing units and improves the purity of the recovered solvent.

[0023] 4. The adsorption unit of the present invention adopts a modular design of the adsorption section. Its pull-out adsorption box structure and convenient sealing baffle switching mechanism make the replacement of adsorbents such as activated carbon simple and quick without interrupting the continuous operation of the entire system. This greatly improves the online maintainability and operating efficiency of the device and ensures the stability of the adsorption and impurity removal effect.

[0024] 5. The neutralization unit of this invention enhances the reaction through mechanical stirring, effectively removing residual bromine and low-bromine phenolic substances.

[0025] 6. The post-processing unit of the present invention utilizes density difference to achieve efficient separation of aqueous and organic phases, as well as precise removal of aqueous phase. Combined with deep dehydration of the adsorption layer, it significantly reduces the moisture and salt content in the recovered chlorobenzene. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. The drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 A schematic diagram of the installation of a solvent recovery device for the preparation of tetrabromobisphenol A;

[0028] Figure 2 for Figure 1Schematic diagram of the bromination unit;

[0029] Figure 3 for Figure 2 A magnified view of a portion of the image;

[0030] Figure 4 for Figure 1 A schematic diagram of the adsorption unit structure;

[0031] Figure 5 for Figure 4 A magnified view of a portion of the image;

[0032] Figure 6 for Figure 1 Schematic diagram of the neutralization unit;

[0033] Figure 7 for Figure 1 Schematic diagram of the mid-to-post-processing unit;

[0034] Explanation of reference numerals in the attached figures:

[0035] 100-Bromination unit, 101-Bromination reactor, 102-Inlet pipe, 103-Outlet pipe, 104-Heating pipe, 105-Support leg, 106-Baffle plate, 107-Blower plate, 108-Exhaust pipe, 109-First dosing pipe, 110-Sampling pipe, 111-Drive pump, 112-Three-way valve, 113-Reflux pipe, 120-Collection section, 121-Collection box, 122-Connecting port, 123-Drain valve, 124-Filter screen;

[0036] 200-Adsorption unit, 201-Adsorption box, 202-Liquid inlet, 203-Liquid outlet, 204-Central channel, 205-Side channel, 210-Adsorption section, 211-Adsorption box, 212-Inner core, 213-Positioning frame, 214-Sealing baffle, 215-Limiting plate;

[0037] 300-Neutralization unit, 301-Tank body, 302-Motor, 303-Rotating shaft, 304-Stirring blade, 305-Inlet pipe, 306-Outlet pipe, 307-Second dosing pipe;

[0038] 400 - Post-processing unit, 401 - Housing, 402 - Feed pipe, 403 - Discharge pipe, 404 - Diverter plate, 405 - Liquid supply pipe, 406 - First guide plate, 407 - Second guide plate, 408 - Diverter pipe, 409 - Adsorption layer. Detailed Implementation

[0039] The features and exemplary embodiments of various aspects of the present invention will now be described in detail. To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only configured to explain the present invention and are not configured to limit the present invention. For those skilled in the art, the present invention can be practiced without some of these specific details. The following description of the embodiments is merely intended to provide a better understanding of the present invention by illustrating examples of the invention.

[0040] The directional terms used in the following description refer to the directions shown in the figures and are not intended to limit the specific structure of the invention. It should also be noted that, unless otherwise explicitly specified and limited, the terms "installation" and "connection" should be interpreted broadly, for example, referring to a fixed connection, a detachable connection, or an integral connection; it can refer to a direct connection or an indirect connection. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0041] An embodiment of the present invention provides a solvent recovery apparatus for the preparation of tetrabromobisphenol A, see [link to relevant documentation]. Figure 1 The solvent recovery device for preparing tetrabromobisphenol A includes a bromination unit 100, an adsorption unit 200, a neutralization unit 300, and a post-treatment unit 400 connected in series via pipelines equipped with pumps.

[0042] The bromination unit 100 is used to further convert low-brominated bisphenol A, such as monobromobisphenol A, dibromobisphenol A, and tribromobisphenol A, contained in chlorobenzene into tetrabromobisphenol A. In this reaction process, bromine and hydrogen peroxide are added quantitatively to the bromination unit 100. Under heating conditions, some of the unconverted low-brominated bisphenol A is further converted into tetrabromobisphenol A and precipitates in the form of crystals. Thus, while reducing the impurity content and purifying the solvent chlorobenzene, a portion of the tetrabromobisphenol A product can be recovered.

[0043] The adsorption unit 200 is used to adsorb the solvent after it has been treated by the bromination unit 100 through activated carbon. On the one hand, it removes excess bromine and other colored impurities, as well as a small amount of phenols that have not been completely washed away. On the other hand, it adsorbs some solid particles and other organic impurities in the solvent through activated carbon.

[0044] Neutralization unit 300 is used to inject NaOH solution into solvent chlorobenzene, where NaOH reacts with residual bromine and low-bromine bisphenol A in the solvent chlorobenzene to generate bromide salt, hypobromite and sodium phenolate.

[0045] The post-treatment unit 400 is used to post-treat the solvent chlorobenzene that has completed the reaction in the neutralization unit 300, so that it is successively washed with water, separated into layers, removed from the aqueous phase, adsorbed, filtered and dried, and finally pure chlorobenzene is obtained.

[0046] For a further explanation of the above embodiments, see Figure 2 , Figure 3 The bromination unit 100 includes a bromination reactor 101. An inlet pipe 102 is fixedly installed at the bottom of the first end of the bromination reactor 101, and the inlet pipe 102 is fixedly connected to the interior of the bromination reactor 101. An outlet pipe 103 is fixedly installed at the top of the second end of the bromination reactor 101, and the outlet pipe 103 is fixedly connected to the interior of the bromination reactor 101. The solvent chlorobenzene to be treated enters the interior of the bromination reactor 101 through the inlet pipe 102, and the solvent chlorobenzene after the bromination reaction is completed is discharged out through the outlet pipe 103.

[0047] A number of heating tubes 104 are uniformly fixedly installed inside the bromination reactor 101 along its length. The two ends of the heating tubes 104 are respectively fixedly connected to the circulating hot water pipe. The circulating hot water transfers heat to the inside of the bromination reactor 101 through the heating tubes 104, thereby heating the solvent chlorobenzene in the bromination reactor 101 and meeting the temperature requirements of the bromination reaction of the low-brominated bisphenol A mixed in therein.

[0048] The bromination reactor 101 is fixedly installed with several partitions 106 along its length, which seal and divide the interior of the bromination reactor 101 into several chambers along its length, so that the chlorobenzene solvent to be treated flows through several chambers in sequence, and the bromination reaction is completed step by step in each chamber, thereby effectively controlling the reaction progress and reaction rate.

[0049] Each chamber is fixedly equipped with a flow-turning plate 107 in the middle. The flow-turning plate 107 divides the bottom of the chamber into two parts, so that the solvent chlorobenzene to be processed can only continue to flow downward after it has passed the top of the flow-turning plate 107, so as to increase the flow path of the solvent chlorobenzene and extend the bromination reaction time.

[0050] Each chamber is equipped with an exhaust pipe 108 fixedly installed on its top to collect and summarize the gases volatilized in each chamber, including bromine and exhaust gases, to prevent environmental pollution.

[0051] Except for the last chamber, the top of each of the other chambers is fixedly equipped with a first dosing tube 109. The first dosing tube 109 is used to deliver bromine and hydrogen peroxide into each chamber to provide reaction raw materials for the bromination reaction.

[0052] A sampling tube 110 is fixedly installed on the top of the last chamber. The sampling tube 110 is used to intermittently extract samples from the inside of the last chamber to detect the content of low-bromine bisphenol A in the samples, thereby adjusting the amount of bromine added to each of the preceding chambers in real time to avoid incomplete reaction due to insufficient bromine addition and waste of raw materials due to excessive bromine addition.

[0053] A drive pump 111 is fixedly installed on the top of the outlet pipe 103. The first port of a three-way valve 112 is fixedly installed on the top of the drive pump 111. The second port of the three-way valve 112 is fixedly connected to the return pipe 113 through a pipeline. The return pipe 113 is installed on the top of the chamber preceding the last chamber. The third port of the three-way valve 112 is fixedly connected to the adsorption unit 200 through a pipeline.

[0054] When the total content of low-brominated bisphenol A in the sample taken from sampling tube 110 is higher than the standard threshold, it indicates that the reaction is not complete. Therefore, the solvent is transferred to the upper chamber through the second outlet of the three-way valve 112 to continue the bromination reaction. When the content of low-brominated bisphenol A in the sample taken from sampling tube 110 is lower than the standard threshold, it indicates that the bromination reaction is basically complete. The sample is then transported to the adsorption unit 200 through the third port of the three-way valve 112.

[0055] The downstream position of each chamber is connected to the upstream position of the next chamber through the collection section 120. The collection section 120 includes a collection box 121, which is fixedly installed at the bottom of the bromination reactor 101. The collection box 121 is fixedly connected to the previous chamber through a communication port 122, which is opened between the partition plate 106 and the flow-turning plate 107 of the previous chamber.

[0056] A drain valve 123 is fixedly installed at the bottom of the collection box 121 to discharge the tetrabromobisphenol A crystals concentrated inside the collection box 121 in stages.

[0057] A filter screen 124 is fixedly installed between the collection box 121 and the next chamber to filter the tetrabromobisphenol A crystals in the collection box 121, so that the tetrabromobisphenol A crystals are retained inside the collection box 121 and prevented from flowing into the next chamber.

[0058] The circulating hot water in the heating tube 104 maintains the system temperature at 80℃~95℃. The above reaction temperature can increase the reaction rate of low-bromine bisphenol A mixed in the solvent chlorobenzene to tetrabromobisphenol A.

[0059] The bromination reactor 101 has several legs 105 fixedly installed at its bottom along its length for supporting and fixing the bromination reactor 101.

[0060] In this embodiment, the number of partitions 106 is preferably two, thereby sealing and dividing the interior of the bromination reactor 101 into three chambers.

[0061] In this configuration, the first dosing tube 109 in each chamber is installed directly above the connecting port 122, so that the tetrabromobisphenol A crystals generated after the reaction can fall into the collection box 121 for collection.

[0062] For a further explanation of the above embodiments, see Figure 4 Figure 5 The adsorption unit 200 includes an adsorption box 201. A liquid inlet 202 is fixedly installed at the first end of the adsorption box 201. The liquid inlet 202 is fixedly connected to the third interface of the three-way valve 112 through a pipeline with a pump body installed. A liquid outlet 203 is fixedly installed at the second end of the adsorption box 201. The liquid outlet 203 is connected to the neutralization unit 300.

[0063] A central channel 204 is provided in the middle of the adsorption box 201. The central channel 204 is fixedly connected to the liquid inlet 202. Side channels 205 are symmetrically provided on the side of the adsorption box 201. The side channels 205 are fixedly connected to the liquid outlet 203. Between the central channel 204 and the side channels 205, a number of adsorption units 210 are uniformly fixedly installed along their length.

[0064] The bromination-treated solvent flows into the central channel 204 through the liquid inlet 202, passes through the adsorption section 210 from the central channel 204 and flows into the side channel 205, forming a radial flow channel structure, and is finally transported to the neutralization unit 300 through the liquid outlet 203.

[0065] During the process of the solvent passing through the adsorption section 210, the adsorption of bromine, some solid particles and other organic impurities in the solution is completed, and the solvent is cleaned for the first time.

[0066] The adsorption unit 210 includes an adsorption box 211, which is filled with an inner core 212. The adsorption box 211 is removably installed inside a positioning frame 213. The positioning frame 213 is fixedly installed between the central channel 204 and the side channel 205 inside the adsorption box 201. A limiting plate 215 is fixedly installed on the side of the positioning frame 213 near the side channel 205. A sealing baffle 214 is installed between the limiting plate 215 and the positioning frame 213 to form a sealed connection.

[0067] The above structure makes the adsorption box 211 easy to replace and install. When the adsorption box 211 needs to be replaced, the sealing baffle 214 is inserted between the limiting plate 215 and the positioning frame 213, thereby blocking the flow of solvent between the central channel 204 and the side channel 205. After inserting the new adsorption box 211 into the positioning frame 213, the sealing baffle 214 is removed, and the flow of solvent between the central channel 204 and the side channel 205 continues.

[0068] The adsorption box 211 has several through holes evenly distributed on its side, which facilitates the flow of solvent into and out of the adsorption box 211 and into the inner core 212 inside the adsorption box 211 to complete the adsorption process and achieve the adsorption effect.

[0069] For a further explanation of the above embodiments, see Figure 6 The neutralization unit 300 includes a vessel body 301. A motor 302 is fixedly installed on the top of the vessel body 301. The output end of the motor 302 is coaxially fixed with the rotating shaft 303. The rotating shaft 303 passes through the top of the vessel body 301 in a sealed manner and is disposed inside the vessel body 301. Several stirring blades 304 are uniformly fixedly installed on the outer surface of the rotating shaft 303 along its axial direction.

[0070] A liquid inlet pipe 305 is fixedly installed on the bottom side of one side of the vessel body 301. The liquid inlet pipe 305 is fixedly connected to the liquid outlet 203 through a pipeline with a pump body installed. A liquid outlet pipe 306 is fixedly installed on the top side of the other side of the vessel body 301. The liquid outlet pipe 306 is connected to the post-processing unit 400.

[0071] A second dosing pipe 307 is fixedly installed on the top side of the vessel body 301. The outlet of the second dosing pipe 307 is located inside the vessel body 301. Sodium hydroxide solution is introduced into the vessel body 301 through the second dosing pipe 307 to achieve alkaline washing of the solvent.

[0072] The solvent, after being adsorbed by the adsorption unit 200, is introduced into the vessel body 301 through the inlet pipe 305. After sodium hydroxide solution is added dropwise through the second dosing pipe 307, the motor 302 drives the stirring blades 304 through the rotating shaft 303 to fully stir the solution in the vessel body 301. The sodium hydroxide reacts with the residual low-bromine bisphenol A and bromine in the solvent. After the reaction is complete, the solution is transported to the post-processing unit 400 through the outlet pipe 306 for post-processing.

[0073] For a further explanation of the above embodiments, see Figure 7 The post-processing unit 400 includes a housing 401. A feed pipe 402 is fixedly installed at the first end of the housing 401. The feed pipe 402 is fixedly connected to the liquid outlet pipe 306 through a pipeline with a pump body installed. A discharge pipe 403 is fixedly installed at the other end of the housing 401 for discharging the processed solvent.

[0074] The interior of the housing 401 is equipped with a first guide plate 406 and a second guide plate 407 arranged vertically. The first guide plate 406 is located on the side near the feed pipe 402, and the second guide plate 407 is located on the side near the discharge pipe 403. The first guide plate 406 is fixed to the bottom of the housing 401, thereby forming a channel between the first guide plate 406 and the top of the housing 401. The second guide plate 407 is fixed to the top of the housing 401, thereby forming a channel between the second guide plate 407 and the bottom of the housing 401. The first guide plate 406 and the second guide plate 407 divide the housing 401 into a first compartment, a second compartment and a third compartment.

[0075] The first compartment serves as the washing area, with a distribution plate 404 fixedly installed at its bottom. A supply pipe 405 is fixedly installed at the bottom of the distribution plate 404. The supply pipe 405 passes through the bottom of the box 401 in a sealed manner. External deionized water is transported to the distribution plate 404 through the supply pipe 405, and after being evenly dispersed, it is transported to the bottom of the first compartment to be fully mixed with the solvent, thereby achieving the effect of washing the solvent.

[0076] The mixture in the first compartment flows into the second compartment through the channel between the first guide plate 406 and the top of the tank 401. The second compartment serves as a stratified zone, and a diversion pipe 408 is fixedly installed on its top for pumping out excess water phase.

[0077] Since the solvent chlorobenzene is immiscible with water and chlorobenzene has a higher density than water, after being thoroughly mixed with deionized water in the first compartment, the salts mixed in the chlorobenzene are dissolved in the deionized water and then transported to the second compartment for stratification of the aqueous and organic phases. At this time, the aqueous phase is located on the upper layer and is slowly drawn out through the diversion pipe 408 and discharged outward.

[0078] The organic phase is located at the bottom and is transported to the third compartment through the channel between the second guide plate 407 and the bottom of the box 401. The third compartment serves as a drying zone, in which an adsorption layer 409 is installed. The adsorption layer 409 is capable of adsorbing excess water phase.

[0079] The adsorption layer 409 can be anhydrous sodium sulfate adsorbent, which effectively adsorbs the moisture in chlorobenzene to achieve the drying effect of chlorobenzene.

[0080] The embodiments described above are not exhaustive and do not limit the invention to only certain specific embodiments. Clearly, many modifications and variations can be made based on the above description. These embodiments are selected and specifically described in this specification to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to effectively utilize the invention and its modifications. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the invention should be included within the scope of protection of the invention.

Claims

1. A solvent recovery apparatus for preparing tetrabromobisphenol A, characterized in that, This includes pipelines connected in series via the pump body: The bromination unit (100) has a multi-stage series chamber structure. Each chamber is equipped with a flow-turning plate (107) to extend the solvent flow path and a heating tube (104) to maintain the system temperature of 80℃~95℃. The top of the final chamber is equipped with a sampling tube (110) and a three-way valve (112) to adjust the solvent flow direction according to the detection results of low-brominated bisphenol A content. The adsorption unit (200) adopts a radial flow channel structure consisting of a central channel (204) and symmetrical side channels (205), and a replaceable activated carbon adsorption section (210) is provided between the channels for dynamic adsorption of bromine and organic impurities. The neutralization unit (300) includes a rotating shaft (303) driven by a motor (302) and a vessel body (301), which is used to add sodium hydroxide reagent into the vessel body (301) to achieve a mixed reaction between sodium hydroxide and residue; The post-processing unit (400) is provided with a water washing zone, a layering zone and a drying zone separated by a first guide plate (406) and a second guide plate (407). A distribution plate (404) is provided at the bottom of the water washing zone to input deionized water into the water washing zone to complete the water washing of the solvent. A distribution pipe (408) is provided at the top of the layering zone to draw out the upper water phase after the organic phase and the aqueous phase are separated. An adsorption layer (409) is built into the drying zone to deeply adsorb the residual moisture in the organic phase. The chambers of the bromination unit (100) are sealed and separated by partitions (106), and adjacent chambers are connected by a bottom collection section (120); The collection section (120) includes a collection box (121) with a filter screen (124) for intercepting and collecting tetrabromobisphenol A crystals. A drain valve (123) is installed at the bottom of the collection box (121) for discharging tetrabromobisphenol A crystals. The adsorption unit (210) includes an adsorption box (211) with through holes and an activated carbon core (212). The adsorption box (211) is inserted into the positioning frame (213). The side of the positioning frame (213) is provided with a pluggable sealing baffle (214) to isolate the flow channel. The first guide plate (406) and the second guide plate (407) are vertically arranged. The first guide plate (406) is fixed to the bottom of the box (401) and forms an overflow channel at the top. The second guide plate (407) is fixed to the top of the box (401) and forms an organic phase channel at the bottom. The bromination unit (100) is used to further convert monobromobisphenol A, dibromobisphenol A and tribromobisphenol A contained in chlorobenzene into tetrabromobisphenol A and precipitate them in the form of crystals, thereby recovering part of the tetrabromobisphenol A product while reducing the impurity content and purifying the solvent chlorobenzene.

2. The solvent recovery apparatus for preparing tetrabromobisphenol A according to claim 1, characterized in that: The first port of the three-way valve (112) is connected to the outlet pipe (103) through the drive pump (111), the second port is connected to the pre-stage chamber through the pipeline to realize reaction recirculation, and the third port is connected to the adsorption unit (200).

3. The solvent recovery apparatus for preparing tetrabromobisphenol A according to claim 1, characterized in that: The connection port (122) of the collection box (121) is located between the partition (106) and the flow plate (107), at the lowest end of the chamber.

4. The solvent recovery apparatus for preparing tetrabromobisphenol A according to claim 1, characterized in that: The adsorption layer (409) is a packed drying layer composed of anhydrous sodium sulfate.

5. The solvent recovery apparatus for preparing tetrabromobisphenol A according to claim 1, characterized in that: The positioning frame (213) has a limiting plate (215) on the side near the side channel (205) for engaging the sealing baffle (214).

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