Vaporization process for preparing high-purity bromine

Abstract

The invention relates to the field of bromine preparation, in particular to a vaporization process for preparing high-purity bromine, which comprises the steps of raw material pretreatment, oxidation reaction, gaseous bromine graded recovery, liquid phase residual bromine enhanced extraction, organic extraction separation and rectification purification. Bromine hydrolysis is inhibited by accurately controlling reaction conditions, and efficient gasification separation of bromine is realized by utilizing multi-stage condensation and segmented evaporation; tail gas is treated by a compound purification system to ensure that environmental protection reaches the standard; impurities are removed through the synergistic effect of extraction and rectification, and finally high-purity bromine is obtained. The process overcomes the defects of low yield and high energy consumption of the traditional method, has the advantages of high efficiency, energy conservation, environmental protection and the like, and is suitable for large-scale industrial application.

Description

Technical Field

[0001] The present invention relates to the field of bromine preparation, and particularly to a vaporization process for preparing high-purity bromine. Background Art

[0002] Bromine, as an important basic chemical raw material, is widely used in fields such as pharmaceutical synthesis, flame retardant materials, and pesticide manufacturing. Currently, in industry, bromine is mainly produced by the brine oxidation method or the electrolysis method. However, there are many bottlenecks in the traditional process, which seriously restricts the improvement of production efficiency and product quality.

[0003] Firstly, inaccurate control of reaction conditions leads to serious loss of bromine. In the oxidation reaction stage, if the pH value or temperature of the reaction system fluctuates, bromine is prone to undergo a reversible hydrolysis reaction with water to generate hypobromous acid and hydrobromic acid. This not only reduces the actual yield of bromine but also increases the difficulty of subsequent separation and purification.

[0004] Secondly, the separation and recovery process is inefficient. Traditional methods mostly rely on a single condensation or evaporation step, making it difficult to fully capture gaseous bromine, resulting in a large amount of bromine remaining in the reaction solution or tail gas. In addition, problems such as high evaporation energy consumption and insufficient condensation efficiency further increase the production cost. Summary of the Invention

[0005] In order to solve the aforementioned technical problems, the present invention provides a vaporization process for preparing high-purity bromine. This equipment precisely controls the reaction conditions and uses the synergistic effects of multi-stage condensation, segmented evaporation, extraction, and rectification to obtain high-purity bromine, solving the defects of low yield and high energy consumption in traditional methods. Specifically, it is achieved through the following technical solutions.

[0006] A vaporization process for preparing high-purity bromine according to the present invention includes the following steps: Step 1, raw material pretreatment: Dilute the bromine-containing raw material and adjust it to an acidic environment to obtain the reaction stock solution; Step 2, oxidation reaction: Heat the reaction stock solution to a temperature higher than the boiling point of bromine, and introduce a mixed gas of carbon dioxide and chlorine for reaction to generate gaseous bromine; Step 3, blowing and collection: Introduce a carrier gas into the reaction system, blow out the gaseous bromine and recover it through multi-stage condensation, and at the same time treat the tail gas; Step 4, vaporization and collection: Perform multi-stage evaporation on the reaction solution, evaporate the residual bromine and recover it through condensation; Step 5, extraction and separation: Mix the bromine solution recovered by condensation with an organic solvent for extraction and separate the organic phase; Step 6, rectification and purification: Rectify the organic phase to separate high-purity bromine and recover the solvent.

[0007] Preferably, in step 1, the bromine-containing raw material is bromine-containing brine or bromine salt solution, the bromide ion concentration in the diluted solution is 20 g / L to 45 g / L, the pH is adjusted to 0.5 to 2.0, the reaction temperature is 40°C to 50°C, and the reaction time is 20 to 30 minutes.

[0008] Preferably, in step 2, the oxidizing mixed gas is a mixed gas of CO2 and Cl2, and the volume ratio is 1:3 to 5; the reaction temperature is 60°C to 90°C, and the reaction is terminated when the bromide ion concentration in the reaction solution is lower than 0.1 g / L.

[0009] Preferably, in step 3, the multi-stage condensation includes primary water cooling and secondary deep cooling, and the primary water cooling is in parallel and then in series with the secondary deep cooling.

[0010] Preferably, in step 4, the multi-stage evaporation includes primary evaporation and secondary evaporation, and the primary evaporation is in parallel and then in series with the secondary evaporation.

[0011] Preferably, in step 5, the organic solvent is xylene, and the volume ratio of it to the bromine solution is 2 to 3:1 to 2.

[0012] Preferably, in step 6, the rectification conditions include: the tower kettle temperature is 120°C to 140°C, the tower top temperature is 50°C to 58°C, the tower internal pressure is 80 kPa to 100 kPa, and the reflux ratio is 2 to 4:1.

[0013] Preferably, in step 3, the tail gas is treated successively through an alkaline spray tower and an activated carbon adsorption tower, and the alkaline solution in the alkaline spray tower is 8% to 15% NaOH solution.

[0014] Preferably, the temperature of the primary water cooling is 30°C to 50°C, and the temperature of the secondary deep cooling is 5°C to 10°C.

[0015] Preferably, the temperature of the primary evaporation is 70°C to 90°C, and the temperature of the secondary evaporation is 120°C to 150°C.

[0016] After adopting the above technical solutions, the beneficial effects of the present invention are as follows: 1. By dynamically regulating the acidity and temperature of the reaction system, the present invention effectively inhibits the side reaction of bromine hydrolysis; combined with multi-stage condensation and staged evaporation technologies, it enhances the capture efficiency of gaseous bromine, significantly reduces the loss of effective components, and finally obtains a high-purity product through rectification and purification.

[0017] 2. The present invention optimizes the design of cascaded utilization of thermal energy, realizes efficient energy transfer in multi-stage treatment units. In addition, the extractant is recycled after rectification, reducing raw material consumption and saving energy and reducing consumption in multiple links.

[0018] 3. The present invention adopts a composite tail gas purification system, which completely eliminates harmful gas emissions through the synergistic effect of chemical neutralization and physical adsorption.

[0019] 4. The integrated design of the impurity separation step in the present invention improves efficiency, shortens the treatment cycle, and comprehensively reduces equipment investment and operating costs. Detailed implementation manners

[0020] The features and exemplary embodiments of various aspects of the present invention will be described in detail below. In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with 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 implemented without some of these specific details. The following description of the embodiments is only intended to provide a better understanding of the present invention by showing examples of the present invention.

[0021] The present invention provides a vaporization process for preparing high-purity bromine, which specifically includes the following steps: Step 1: Raw material pretreatment Dilute the bromine-containing brine or bromine salt solution until the Br - concentration in the solution is 20 g / L to 45 g / L, and slowly add concentrated sulfuric acid to the solution to adjust the pH of the solution to 0.5 to 2.0 to obtain a reaction stock solution.

[0022] Among them, the temperature is controlled at 40°C to 50°C and the reaction time is 20 min to 30 min during the above process.

[0023] In the above step, the Br - concentration adjustment is carried out to more conveniently balance the reaction rate and the yield. Too high a concentration may cause the reaction to be too violent or Br2 to precipitate prematurely, increasing the treatment difficulty, while too low a concentration will reduce the reaction rate.

[0024] In addition, adjusting the pH of the solution to 0.5 to 2.0 to maintain a strong acid environment of the reaction stock solution facilitates the subsequent oxidation reaction; and after Br2 is generated by oxidation subsequently, a hydrolysis reaction will occur synchronously: Br2 + H2O → HBrO + H + + Br - When the reaction stock solution is in a strong acid environment, the above hydrolysis reaction will be inhibited, thereby reducing the loss of Br2.

[0025] Among them, by utilizing the heat dissipation effect of diluting concentrated sulfuric acid, the temperature of the reaction stock solution is adjusted to 40°C to 50°C. Since the boiling point of Br2 is 59°C, therefore, on the premise of not exceeding the above temperature, appropriately increasing the temperature can improve the molecular thermal motion and promote the progress of the oxidation reaction.

[0026] Step 2: Oxidation reaction Input the reaction stock solution obtained in Step 1 into an enamel reaction kettle, heat the reaction stock solution to 60°C to 90°C, and introduce a mixed gas of CO2 and Cl2 according to a volume ratio of CO2:Cl2 of 1:3 to 5. The concentration of Br in the reaction stock solution is monitored in real time through a concentration sensor. - Concentration, when the concentration of Br - is lower than 0.1 g / L, terminate the reaction.

[0027] In the above process, when Cl2 is introduced, a chemical reaction occurs: Cl2 + 2Br − → 2Cl − + Br2; The temperature is controlled at 60°C to 90°C because the boiling point of Br2 is 59°C, and gasification can be achieved within this temperature range to realize the preliminary separation of Br2 from the solution; in addition, high temperature can improve the ionic activity in the solution, thereby promoting the progress of the above oxidation reaction.

[0028] Step 3: Blowing and collecting Introduce air from one side of the reaction kettle, collect the gas on the other side of the reaction kettle, subject the collected gas to multi-stage condensation and liquefaction, collect the condensed liquid as the primary bromine liquid for standby, and the gas output from the condensation passes through an alkaline spray tower and an activated carbon adsorption tower in sequence.

[0029] Among them, multi-stage condensation includes primary water cooling at a temperature of 30°C to 50°C and secondary deep cooling at a temperature of 5°C to 10°C. Multiple primary water coolings are connected in parallel and then in series with the secondary deep cooling.

[0030] In the process of recovering Br2 in the gas through multi-stage condensation, the connection method of the primary water cooling and the secondary deep cooling, that is, multiple primary water coolings ensure the efficiency of Br2 condensation, and the secondary deep cooling can reduce the residual amount of Br2 in the gas to the greatest extent.

[0031] Among them, the spraying liquid in the alkaline spray tower is an 8% to 15% NaOH solution.

[0032] In Step 2, the generated Br2 vaporizes under the temperature condition of 60°C to 90°C. Therefore, by introducing air into the reaction kettle, the Br2 concentrated on the upper layer of the reaction kettle is blown out. Since the gas in the reaction kettle contains CO2, Cl2, and Br2, by utilizing the characteristic of the low boiling point of Br2, the Br2 in the above gas is condensed and liquefied for recovery and standby, which is convenient for subsequent further purification.

[0033] The CO2, Cl2 and a part of the remaining Br2 in the tail gas react chemically with the spraying liquid in the alkaline spraying tower, thereby removing the harmful gases in the tail gas; in addition, a small amount of the tail gas that has not fully reacted is adsorbed by the activated carbon adsorption tower to avoid the leakage of harmful gases.

[0034] Step 4: Vaporization and collection The reaction liquid in the reaction kettle is subjected to multi-stage evaporation to distill out Br2 in the reaction liquid. The evaporation gas is liquefied by multi-stage condensation, and the condensed liquid is collected and reserved as secondary bromine liquid. The gas output from the condensation passes through the alkaline spraying tower and the activated carbon adsorption tower in sequence.

[0035] Among them, the multi-stage evaporation includes a first-stage evaporation at a temperature of 70°C to 90°C and a second-stage evaporation at a temperature of 120°C to 150°C. A plurality of first-stage evaporations are connected in parallel and then in series with the second-stage evaporation. Through the plurality of parallel first-stage evaporations, Br2 can be evaporated with the highest efficiency, but there will still be some bromine remaining in the reaction liquid. Therefore, the remaining Br2 is further distilled out through the second-stage evaporation.

[0036] Among them, the time of the above-mentioned first-stage evaporation is 20 min to 30 min, and the time of the second-stage evaporation is 15 min to 25 min.

[0037] Adopting the method of segmented distillation can, on the one hand, improve the distillation speed, and on the other hand, reduce energy consumption, save energy and protect the environment.

[0038] Among them, the multi-stage condensation, alkaline spraying tower and activated carbon adsorption tower in this step are set in the same way as in Step 3.

[0039] Step 5: Extraction and separation The primary bromine liquid and the secondary bromine liquid are mixed, and xylene is added in a volume ratio of xylene:bromine liquid = 2 - 3:1 - 2 to extract and separate the organic phase.

[0040] Due to the preparation process of the primary bromine liquid and the secondary bromine liquid, Br2 is vaporized by heating and then collected by the condensation method. The primary bromine liquid and the secondary bromine liquid will contain some moisture and salt impurities. Xylene is used to extract bromine, thereby effectively separating bromine from the above-mentioned impurities.

[0041] Step 6: Rectification and purification The organic phase obtained in Step 5 is transported into the rectification tower for rectification. The gas generated by the rectification is collected and condensed to obtain high-purity Br2, and the remaining liquid phase after rectification is recycled.

[0042] During the rectification process completed by the above-mentioned rectification tower, the temperature at the bottom of the tower is 120°C to 140°C, the temperature at the top of the tower is 50°C to 58°C, the pressure inside the tower is 80 kPa to 100 kPa, and the reflux ratio is 2 - 4:1.

[0043] In the above steps, the condensation temperature is 15°C to 30°C.

[0044] In this process, considering that the boiling point of Br2 is 59°C and the boiling point of xylene is 138°C to 145°C, the temperature of the bottom of the tower is controlled at 120°C to 140°C, and the temperature of the top of the tower is controlled at 50°C to 58°C, so that the extraction liquid is always in a distillation state in the distillation column, thereby efficiently distilling out the Br2 inside the organic phase.

[0045] The distilled gas is condensed into high-purity Br2, and the remaining liquid phase after distillation is xylene, which can be recycled to the extraction step in step 5 to reduce production costs.

[0046] For the convenience of further understanding of the present invention, several embodiments and comparative examples of the present invention are given below: Example 1 Step 1: Dilute the bromine-containing brine until the concentration of Br in the solution - is 35 g / L. Slowly add concentrated sulfuric acid to the solution, adjust the pH of the solution to 1.5, adjust the temperature to 45°C, and keep it warm for 20 min to obtain a reaction stock solution.

[0047] Step 2: Input the reaction stock solution into an enamel reaction kettle, heat it to 75°C, and introduce a mixed gas of CO2 and Cl2 with a volume ratio of CO2:Cl2 of 1:3 until the concentration of Br - is lower than 0.1 g / L, and terminate the reaction.

[0048] Step 3: Blow out the upper gas in the reaction kettle with air, and condense it successively with primary water cooling at 40°C and secondary deep cooling at 10°C, and collect the condensate for standby. The condensate tail gas is successively absorbed by spraying with 10% NaOH solution and adsorbed by activated carbon.

[0049] Step 4: Evaporate the reaction liquid in the reaction kettle successively with primary evaporation at 80°C and secondary evaporation at 140°C. The primary evaporation time is 30 min, and the secondary evaporation time is 15 min. The evaporated gas is condensed successively with primary water cooling at 40°C and secondary deep cooling at 10°C, and collect the condensate for standby. The condensate tail gas is successively absorbed by spraying with 10% NaOH solution and adsorbed by activated carbon.

[0050] Step 5: Mix the condensates in step 3 and step 4, and add xylene with a volume twice that of the condensate to extract and separate the organic phase.

[0051] Step 6: Transport the organic phase into the distillation column. The temperature of the bottom of the tower is 130°C, the temperature of the top of the tower is 57°C, the pressure inside the tower is 80 kPa, and the reflux ratio is 4:1. The gas generated by distillation is condensed at 20°C to obtain high-purity Br2, and the remaining xylene after distillation is recycled to step 5.

[0052] Example 2 This example is based on Example 1 and adjusts the parameters of the reaction stock solution in Step 1, specifically as follows: Step 1: Dilute the bromine-containing brine until the Br - concentration in the solution is 35 g / L. Slowly add concentrated sulfuric acid to the solution, adjust the pH of the solution to 2.0, adjust the temperature to 40 °C, and keep it warm for 20 min to obtain the reaction stock solution.

[0053] The remaining steps and conditions are the same as those in Example 1.

[0054] Example 3 This example is based on Example 1 and adjusts the ratio of the mixed gas in Step 2, specifically as follows: Step 2: Input the reaction stock solution into an enamel reaction kettle, heat it to 75 °C, and introduce a mixed gas of CO2 and Cl2 with a volume ratio of CO2:Cl2 of 1:5 until the Br - concentration is lower than 0.1 g / L, and terminate the reaction.

[0055] The remaining steps and conditions are the same as those in Example 1.

[0056] Example 4 This example is based on Example 1 and adjusts the temperature of the first-stage water cooling in Steps 3 and 4, specifically as follows: Step 3: Use air to blow out the gas on the upper layer of the reaction kettle, and successively condense it with 50 °C first-stage water cooling and 10 °C second-stage deep cooling, collect the condensate for standby, and successively absorb the condensate tail gas through spraying with 10% NaOH solution and adsorption with activated carbon.

[0057] Step 4: Evaporate the reaction solution in the reaction kettle successively with 80 °C first-stage evaporation and 140 °C second-stage evaporation. The first-stage evaporation time is 30 min, and the second-stage evaporation time is 15 min. The evaporated gas is successively condensed with 50 °C first-stage water cooling and 10 °C second-stage deep cooling, collect the condensate for standby, and successively absorb the condensate tail gas through spraying with 10% NaOH solution and adsorption with activated carbon.

[0058] The remaining steps and conditions are the same as those in Example 1.

[0059] Example 5 This example is based on Example 1 and adjusts the parameters of the distillation column in Step 6, specifically as follows: Step 6: Transport the organic phase into the distillation column. The temperature at the bottom of the column is 120 °C, the temperature at the top of the column is 55 °C, the pressure inside the column is 80 kPa, the reflux ratio is 4:1, and the gas generated by distillation is condensed under the condition of 20 °C to obtain high-purity Br2. The remaining xylene after distillation is recycled to Step 5.

[0060] The remaining steps and conditions are the same as those in Example 1.

[0061] Comparative Example 1 This comparative example is based on Example 1, and the gas introduced in Step 2 is adjusted, and CO2 is no longer added. Specifically: Step 2: Input the reaction stock solution into an enamel reactor, heat it to 75 °C, and introduce Cl2 until the Br - concentration is lower than 0.1 g / L, and the reaction is terminated.

[0062] The remaining steps and conditions are the same as those in Example 1.

[0063] Comparative Example 2 This example is based on Example 1, and the condensation method in Steps 3 and 4 is adjusted, and fractional condensation is no longer used. Specifically: Step 3: Use air to blow out the upper-layer gas in the reactor, condense it in a 10 °C condensation environment, collect the condensate for standby, and the condensation tail gas is sequentially absorbed by spraying with 10% NaOH solution and adsorbed by activated carbon.

[0064] Step 4: Evaporate the reaction solution in the reactor by first-stage evaporation at 80 °C and second-stage evaporation at 140 °C in sequence. The first-stage evaporation time is 30 min, and the second-stage evaporation time is 15 min. The evaporated gas is condensed in a 10 °C condensation environment, collect the condensate for standby, and the condensation tail gas is sequentially absorbed by spraying with 10% NaOH solution and adsorbed by activated carbon.

[0065] The remaining steps and conditions are the same as those in Example 1.

[0066] Comparative Example 3 This example is based on Example 1, and the evaporation method in Step 4 is adjusted, and fractional evaporation is no longer used. Specifically: Step 4: Evaporate the reaction solution in the reactor at 140 °C, and the evaporation time is 40 min. The evaporated gas is condensed by first-stage water cooling at 40 °C and second-stage deep cooling at 10 °C in sequence. Collect the condensate for standby, and the condensation tail gas is sequentially absorbed by spraying with 10% NaOH solution and adsorbed by activated carbon.

[0067] The remaining steps and conditions are the same as those in Example 1.

[0068] Taking 1500 L of bromine-containing brine with a Br - concentration of 55 g / L as an example, the above-mentioned steps and methods recorded in the examples and comparative examples are respectively used for the purification of bromine, and the consumption of Cl2 in the oxidation stage, the amount and purity of bromine obtained by condensing the blown-out gas, and the amount and purity of bromine obtained by final rectification in each example and comparative example are recorded. The recorded data are as follows:

[0069] According to the above data, it can be known that: In Example 2, the pH in Step 1 was adjusted from 1.5 to 2.0, and the temperature was decreased from 45 °C to 40 °C. The weakening of acidity led to a decrease in the oxidation reaction rate, and more Cl2 was required to complete the reaction. At the same time, the effect of high temperature in inhibiting the hydrolysis of Br2 weakened, and part of the Br2 was lost, resulting in a decrease in the amount and purity of the condensed bromine.

[0070] In Example 3, the ratio of CO2 to Cl2 was adjusted to 1:5. The decrease in the proportion of CO2 increased the concentration of Cl2. During the reaction process, too high a local concentration of Cl2 would cause side reactions, thereby reducing the utilization rate of Cl2 and increasing its consumption. In addition, the side reactions would cause a small amount of Br2 to decompose due to local overheating, resulting in a slight decrease in the amount and purity of the condensed bromine.

[0071] In Example 4, the temperature of the first-stage water cooling was increased to 50 °C, resulting in a decrease in the condensation efficiency. Part of the Br2 was not fully liquefied. In addition, Br2 was more likely to remain in the gas phase at high temperature, further reducing the recovery rate.

[0072] In Example 5, the temperature of the bottom of the distillation column was decreased, resulting in a decrease in the separation efficiency of xylene and Br2. Part of the Br2 remained in the liquid phase. However, since the temperature at the top of the column was close to the boiling point of Br2, the purity was less affected.

[0073] In Comparative Example 1, no CO2 was added, resulting in too high a concentration of Cl2 during the reaction with Br - The reaction was intense and the side reactions increased. Part of the Br2 decomposed due to local overheating. The consumption of Cl2 increased significantly, and the amount and purity of the condensed bromine decreased significantly.

[0074] In Comparative Example 2, the staged condensation was cancelled, and direct deep cooling at 10 °C was used. The concentration of Br2 in the gas not pretreated by the first-stage water cooling was too high, resulting in too large a deep cooling load. Part of the Br2 was not completely captured, thus reducing the amount of condensed bromine, and the condensed purity decreased due to the residual impurities.

[0075] In Comparative Example 3, the staged evaporation was cancelled, and direct evaporation at 140 °C was used. The high temperature caused thermal decomposition of part of the Br2 and uneven evaporation led to an increase in the amount of residual bromine, resulting in a decrease in the final amount of distilled bromine, and the purity was slightly lower because the impurities were not removed in stages.

[0076] According to the embodiments of the present invention as described above, these embodiments do not describe all the details in detail, nor do they limit the invention to only the specific embodiments. Obviously, according to the above description, many modifications and variations can be made. These embodiments are selected and specifically described in this specification in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can make good use of the present invention and its modified use based on the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A vaporization process for preparing high-purity bromine, characterized in that, It includes the following steps: Step 1, raw material pretreatment: Dilute the bromine-containing raw material and adjust it to an acidic environment to obtain a reaction stock solution; Step 2, oxidation reaction: Heat the reaction stock solution to a temperature higher than the boiling point of bromine, and introduce a mixed gas of carbon dioxide and chlorine for reaction to generate gaseous bromine; Step 3, blowing and collection: Introduce a carrier gas into the reaction system, blow out the gaseous bromine and recover it through multi-stage condensation, and treat the tail gas at the same time; Step 4, vaporization and collection: Perform multi-stage evaporation on the reaction solution, evaporate the residual bromine and recover it through condensation; Step 5, extraction and separation: Mix the bromine solution recovered by condensation with an organic solvent for extraction and separate the organic phase; Step 6, rectification and purification: Perform rectification on the organic phase to separate high-purity bromine and recover the solvent.

2. The vaporization process for preparing high-purity bromine according to claim 1, characterized in that, In Step 1, the bromine-containing raw material is bromine-containing brine or bromide solution. After dilution, the bromide ion concentration in the solution is 20 g / L to 45 g / L, the pH is adjusted to 0.5 to 2.0, the reaction temperature is 40°C to 50°C, and the reaction time is 20 to 30 minutes.

3. The vaporization process for preparing high-purity bromine according to claim 1, characterized in that, In Step 2, the oxidizing mixed gas is a mixed gas of CO2 and Cl2 with a volume ratio of 1:3 to 5; the reaction temperature is 60°C to 90°C, and the reaction is terminated when the bromide ion concentration in the reaction solution is lower than 0.1 g / L.

4. The vaporization process for preparing high-purity bromine according to claim 1, characterized in that, In Step 3, the multi-stage condensation includes primary water cooling and secondary deep cooling, and the primary water cooling is in parallel and then in series with the secondary deep cooling.

5. The vaporization process for preparing high-purity bromine according to claim 1, characterized in that, In Step 4, the multi-stage evaporation includes primary evaporation and secondary evaporation, and the primary evaporation is in parallel and then in series with the secondary evaporation.

6. The vaporization process for preparing high-purity bromine according to claim 1, characterized in that, In Step 5, the organic solvent is xylene, and its volume ratio to the bromine solution is 2 to 3:1 to 2.

7. The vaporization process for preparing high-purity bromine according to claim 1, characterized in that, In Step 6, the rectification conditions include: the tower bottom temperature is 120°C to 140°C, the tower top temperature is 50°C to 58°C, the tower internal pressure is 80 kPa to 100 kPa, and the reflux ratio is 2 to 4:

1.

8. The vaporization process for preparing high-purity bromine according to claim 1, characterized in that, In Step 3, the tail gas is treated successively through an alkaline spray tower and an activated carbon adsorption tower. The alkaline solution in the alkaline spray tower is 8% to 15% NaOH solution.

9. The vaporization process for preparing high-purity bromine according to claim 4, characterized in that, The temperature of the primary water cooling is 30°C to 50°C, and the temperature of the secondary deep cooling is 5°C to 10°C.

10. The vaporization process for preparing high-purity bromine according to claim 5, characterized in that, The temperature of the primary evaporation is 70°C to 90°C, and the temperature of the secondary evaporation is 120°C to 150°C.

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