A method for the production of bromine

Abstract

The application is suitable for the technical field of inorganic substance preparation method, and provides a preparation method of bromine, which comprises the following steps: step one: a certain amount of sodium bromide and hydrobromic acid are added into a mother liquor pool and stirred to obtain a mother liquor; step two: a predetermined amount of stearic acid and polyvinylpyrrolidone are added; step three: preheating is carried out, and then the preheating is fed into an absorption tower; step four: the liquid at the bottom of the absorption tower flows into the upper part of a bromine evaporation tower, and is heated by steam in the bromine evaporation tower; water vapor and chlorine gas are introduced from the bottom of the bromine evaporation tower, and bromine steam enters the absorption tower; step five: the distillation acid liquid generated by the bromine evaporation tower flows into a preheater to be preheated; bromine steam flows out from the upper part of the bromine evaporation tower to obtain a bromine and water mixture; step six: the bromine and water mixture flows into a bromine water separation bottle to be separated, and bromine products are obtained, thereby, the bromine source is hydrogen bromide and sodium bromide; the stearic acid can effectively reduce the surface tension, so that the reaction is more uniform, and the system is stable.

Description

Technical Field

[0001] This invention relates to the field of inorganic preparation methods and provides a method for preparing bromine. Background Technology

[0002] Bromine is an important chemical raw material and a major branch of the marine chemical industry. Its diverse derivatives, including inorganic bromides, bromates, and bromine-containing organic compounds, hold special value in national economic and technological development. Bromine is also widely used in flame retardants, fire extinguishing agents, refrigerants, photosensitive materials, pharmaceuticals, pesticides, and oil fields. Its primary uses include the production of bromides, as a general analytical reagent, oxidant, absorbent for ethylene and hydrocarbons, and brominating agent in organic synthesis.

[0003] In existing bromine production processes, the bromide reaction is uneven, which affects the subsequent yield. Furthermore, conventional methods use chlorine gas to displace bromine from a hydrobromic acid solution, but this produces a large amount of hydrochloric acid, increasing the difficulty of water treatment and making the process inconvenient. Summary of the Invention

[0004] To address the aforementioned deficiencies, the present invention aims to provide a method for preparing bromine, which addresses the problems mentioned above, and includes the following steps:

[0005] Step 1: Add deionized water to the mother liquor tank, then add a certain amount of sodium bromide and hydrobromic acid and stir to obtain the mother liquor;

[0006] Step 2: Add a predetermined amount of stearic acid and polyvinylpyrrolidone to the mother liquor tank. The mass percentage of polyvinylpyrrolidone in the mother liquor is 1-10%.

[0007] Step 3: The mother liquor in the mother liquor tank is flowed to the preheater for preheating, and then enters the absorption tower from the preheater;

[0008] Step 4: The liquid at the bottom of the absorption tower flows into the upper part of the bromine stripping tower and is heated by the steam inside the bromine stripping tower. Water vapor and chlorine gas are introduced from the bottom of the bromine stripping tower, and the bromine vapor generated in the bromine stripping tower enters the absorption tower.

[0009] Step 5: The distilled acid solution produced by the bromine distillation tower flows from the bottom of the tower into the preheater for preheating, then is cooled by the cooler and neutralized with sodium bicarbonate solution; bromine vapor flows out from the top of the tower to obtain a mixture of bromine and water.

[0010] Step 6: The mixture of bromine and water flows into a bromine-water separation bottle for separation to obtain the bromine product.

[0011] Furthermore, in step one, the sodium bromide powder accounts for 30% of the mass percentage of deionized water, and the 60% concentration hydrobromic acid solution accounts for 10% of the mass percentage of deionized water.

[0012] Furthermore, in step one, the sodium bromide is stirred for 30 minutes, and then hydrobromic acid is added and stirred for another 30 minutes.

[0013] Furthermore, the mass percentage of stearic acid in the mother liquor in step two is 1-10%.

[0014] Furthermore, the preheating temperature in step three is 50℃-70℃.

[0015] Furthermore, in step four, the temperature at the top of the bromine distillation tower is 85°C.

[0016] Furthermore, in step four, the mass ratio of chlorine gas to the sum of the masses of sodium bromide and hydrobromic acid in step one is 1:2.

[0017] Furthermore, the concentration of the sodium bicarbonate solution in step five is 30%.

[0018] Furthermore, the pressure of the bromine water separation bottle in step six is ​​0.15 MPa.

[0019] Furthermore, in step six, the temperature is maintained at 30°C.

[0020] Beneficial effects

[0021] The bromine sources of this invention are hydrogen bromide and sodium bromide. During the bromine production process, polyvinylpyrrolidone can effectively reduce surface tension, promote emulsification of bromine with other substances, and make the reaction more uniform. In addition, stearic acid can stabilize the generated bromide, prevent it from precipitating or separating, and maintain the stability of the system. The preheating process promotes the chemical reaction and increases the yield of bromine. The distilled acid solution produced in the bromine distillation tower is neutralized with sodium bicarbonate solution after preheating the mother liquor, without generating waste and making full use of the distilled acid solution. The condenser pressure is maintained within a certain range to achieve full condensation of bromine vapor, and the bromine water separation bottle achieves the separation of bromine and bromine water at a certain pressure and temperature. Attached Figure Description

[0022] Figure 1 This is a schematic diagram illustrating the principle of the present invention. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0024] See Figure 1 The purpose of this invention is to provide a method for preparing bromine, comprising the following steps:

[0025] Step 1: A certain amount of sodium bromide and hydrobromic acid are added to the mother liquor tank and stirred to obtain the mother liquor. Sodium bromide and hydrobromic acid are the bromine sources.

[0026] Step 2: Add stearic acid to the mother liquor tank, with a mass percentage of 1-10%, and stir. Stearic acid is a long-chain fatty acid with excellent emulsifying and stabilizing properties. During bromine production, stearic acid can also stabilize the generated bromide, preventing precipitation or stratification and maintaining system stability. Then, add polyvinylpyrrolidone (PVP). PPVP effectively reduces surface tension, promotes emulsification of bromine with other substances, and makes the reaction more uniform.

[0027] Step 3: The obtained mother liquor flows to the preheater for preheating, and then enters the absorption tower from the preheater; preheating promotes the dissolution of stearic acid.

[0028] Step 4: Then, the mother liquor flows from the bottom outlet of the absorption tower into the top inlet of the bromine distillation tower. It enters from the top of the bromine distillation tower and is heated by the steam inside. Water vapor and chlorine are introduced from the bottom of the bromine distillation tower. The mother liquor flows from top to bottom along the surface of the packing in the bromine distillation tower, contacting the chlorine and water vapor flowing from bottom to top. 2NaBr + Cl2 = Br2 + 2NaCl, 2HBr + Cl2 = Br2 + 2HCl. The mass ratio of chlorine to the sum of sodium bromide and hydrobromic acid in Step 1 is 1:2. The water vapor is introduced for 30 minutes. Bromine is oxidized and distilled to obtain bromine vapor. The temperature at the top of the bromine distillation tower is controlled at 85℃. Controlling the temperature at the top of the bromine distillation tower ensures complete separation of bromine from the liquid. This temperature control can guarantee the bromine yield and product quality. The bromine vapor enters the absorption tower, thereby achieving the enrichment of bromine vapor.

[0029] Step 5: The distilled acid solution produced in the bromine distillation tower is discharged from the bottom of the tower and flows into the preheater to preheat the mother liquor. It is then further cooled by a cooler and neutralized by a 30% sodium bicarbonate solution to produce sodium bromide and carbon dioxide, reducing waste gas emissions and generating salts that can be recycled. Bromine vapor is discharged from the upper outlet pipe of the bromine distillation tower, resulting in a mixture of bromine and water.

[0030] Step Six: The mixture of bromine and water flows into the bromine-water separation bottle, with the pressure maintained at 0.15 MPa and the temperature maintained at 30°C. Maintaining a certain pressure and temperature ensures the normal operation of the bromine-water separator and achieves good separation results. Bromine and bromine water are separated in the bromine-water separation bottle, and the bromine enters the bromine storage tank to obtain the bromine product.

[0031] Example 1:

[0032] Step 1: Add deionized water to the mother liquor tank, add sodium bromide powder to the deionized water and stir for 30 minutes. The sodium bromide accounts for 30% of the mass percentage of the deionized water. Add a 60% concentration hydrobromic acid solution and stir for 30 minutes. The hydrobromic acid solution accounts for 10% of the mass percentage of the deionized water. The mother liquor is then obtained.

[0033] Step 2: Add stearic acid to the mother liquor tank, with a mass percentage of 1% in the mother liquor, and then add polyvinylpyrrolidone, with a mass percentage of 1% in the mother liquor.

[0034] Step 3: Use a mother liquor pump to pump the mother liquor to the preheater to preheat the mother liquor to 50℃ for 30 minutes; then flow it into the absorption tower.

[0035] Step 4: The solution enters the bromine stripping tower through the absorption tower and is heated by the steam inside the bromine stripping tower. The temperature at the top of the bromine stripping tower is controlled at 85°C. Chlorine gas is introduced, with a weight ratio of chlorine gas to sodium bromide and hydrobromic acid in Step 1 of 1:2. Then, saturated steam at 130°C is introduced for 30 minutes. The bromine vapor obtained from the bromine stripping tower is introduced into the absorption tower for absorption and enrichment.

[0036] Step 5: The distilled acid solution produced in the bromine distillation tower is discharged from the bottom of the tower and flows into the preheater to preheat the mother liquor. Then it is further cooled by the cooler and neutralized by a 30% sodium bicarbonate solution to produce sodium bromide and carbon dioxide. Bromine vapor is discharged from the upper outlet pipe of the bromine distillation tower to obtain a mixture of bromine and water.

[0037] Step 6: The mixture of bromine and water flows into a bromine-water separation bottle, with the pressure maintained at 0.15 MPa and the temperature maintained at 30°C. Bromine and bromine water are separated in the bromine-water separation bottle. The bromine enters the bromine storage tank to obtain the bromine product. The bromine yield is 99.2%.

[0038] Example 2:

[0039] Step 1: Add deionized water to the mother liquor tank, add sodium bromide powder to the deionized water and stir for 30 minutes. The sodium bromide accounts for 30% of the mass percentage of the deionized water. Add a 60% concentration hydrobromic acid solution and stir for 30 minutes. The hydrobromic acid solution accounts for 10% of the mass percentage of the deionized water. The mother liquor is then obtained.

[0040] Step 2: Add stearic acid to the mother liquor tank, with a mass percentage of 5% in the mother liquor. Then add polyvinylpyrrolidone, with a mass percentage of 5% in the mother liquor.

[0041] Step 3: Use a mother liquor pump to pump the mother liquor to the preheater to preheat the mother liquor to 60℃ for 30 minutes; then flow it into the absorption tower.

[0042] Step 4: The solution enters the bromine stripping tower through the absorption tower and is heated by the steam inside the bromine stripping tower. The temperature at the top of the bromine stripping tower is controlled at 85°C. Chlorine gas is introduced, with a weight ratio of chlorine gas to sodium bromide and hydrobromic acid in Step 1 of 1:2. Then, saturated steam at 130°C is introduced for 30 minutes. The bromine vapor obtained from the bromine stripping tower is introduced into the absorption tower for absorption and enrichment.

[0043] Step 5: The distilled acid solution produced in the bromine distillation tower is discharged from the bottom of the tower and flows into the preheater to preheat the mother liquor. Then it is further cooled by the cooler and neutralized by a 30% sodium bicarbonate solution to produce sodium bromide and carbon dioxide. Bromine vapor is discharged from the upper outlet pipe of the bromine distillation tower to obtain a mixture of bromine and water.

[0044] Step 6: The mixture of bromine and water flows into a bromine-water separation bottle, with the pressure maintained at 0.15 MPa and the temperature maintained at 30°C. Bromine and bromine water are separated in the bromine-water separation bottle. The bromine enters the bromine storage tank to obtain the bromine product. The bromine yield is 99.7%.

[0045] Example 3:

[0046] Step 1: Add deionized water to the mother liquor tank, add sodium bromide powder to the deionized water and stir for 30 minutes. The sodium bromide accounts for 30% of the mass percentage of the deionized water. Add a 60% concentration hydrobromic acid solution and stir for 30 minutes. The hydrobromic acid solution accounts for 10% of the mass percentage of the deionized water. The mother liquor is then obtained.

[0047] Step 2: Add stearic acid to the mother liquor tank, with a mass percentage of 10% in the mother liquor, and then add polyvinylpyrrolidone, with a mass percentage of 10% in the mother liquor.

[0048] Step 3: Use a mother liquor pump to pump the mother liquor to the preheater to preheat the mother liquor to 70℃ for 30 minutes; then flow it into the absorption tower.

[0049] Step 4: The solution enters the bromine stripping tower through the absorption tower and is heated by the steam inside the bromine stripping tower. The temperature at the top of the bromine stripping tower is controlled at 85°C. Chlorine gas is introduced, with a weight ratio of chlorine gas to sodium bromide and hydrobromic acid in Step 1 of 1:2. Then, saturated steam at 130°C is introduced for 30 minutes. The bromine vapor obtained from the bromine stripping tower is introduced into the absorption tower for absorption and enrichment.

[0050] Step 5: The distilled acid solution produced in the bromine distillation tower is discharged from the bottom of the tower and flows into the preheater to preheat the mother liquor. Then it is further cooled by the cooler and neutralized by a 30% sodium bicarbonate solution to produce sodium bromide and carbon dioxide. Bromine vapor is discharged from the upper outlet pipe of the bromine distillation tower to obtain a mixture of bromine and water.

[0051] Step 6: The mixture of bromine and water flows into a bromine-water separation bottle, with the pressure maintained at 0.15 MPa and the temperature maintained at 30°C. Bromine and bromine water are separated in the bromine-water separation bottle. The bromine enters the bromine storage tank to obtain the bromine product. The bromine yield is 99.1%.

[0052] In summary, the bromine sources of this invention are hydrogen bromide and sodium bromide; during the bromine production process, polyvinylpyrrolidone can effectively reduce surface tension, promote the emulsification of bromine with other substances, and make the reaction more uniform. Furthermore, stearic acid can stabilize the generated bromide, preventing precipitation or stratification and maintaining system stability; the preheating process promotes the chemical reaction and increases the bromine yield; the distilled acid solution produced in the bromine distillation tower is neutralized with sodium bicarbonate solution after preheating the mother liquor, producing no waste and fully utilizing the distilled acid solution; the condenser pressure is maintained within a certain range to achieve sufficient condensation of bromine vapor, and the bromine water separation bottle achieves the separation of bromine and bromine water at a certain pressure and temperature.

[0053] Of course, the present invention may have other various embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and modifications according to the present invention, but these corresponding changes and modifications should all fall within the protection scope of the appended claims.

Claims

1. A method for preparing bromine, characterized in that: Includes the following steps: Step 1: Add deionized water to the mother liquor tank, then add a certain amount of sodium bromide and hydrobromic acid and stir to obtain the mother liquor; Step 2: Add a predetermined amount of stearic acid and polyvinylpyrrolidone to the mother liquor tank. The mass percentage of polyvinylpyrrolidone in the mother liquor is 1-10%. Step 3: The mother liquor in the mother liquor tank is flowed to the preheater for preheating, and then enters the absorption tower from the preheater; Step 4: The liquid at the bottom of the absorption tower flows into the upper part of the bromine stripping tower and is heated by the steam inside the bromine stripping tower. Water vapor and chlorine gas are introduced from the bottom of the bromine stripping tower, and the bromine vapor generated in the bromine stripping tower enters the absorption tower. Step 5: The distilled acid solution produced by the bromine distillation tower flows from the bottom of the tower into the preheater for preheating, then is cooled by the cooler and neutralized with sodium bicarbonate solution; Bromine vapor flows out from the top of the bromine distillation tower to obtain a mixture of bromine and water; Step 6: The mixture of bromine and water flows into a bromine-water separation bottle for separation to obtain the bromine product; In step one, sodium bromide powder accounts for 30% of the mass percentage of deionized water, and a 60% concentration hydrobromic acid solution accounts for 10% of the mass percentage of deionized water. In step two, the mass percentage of stearic acid in the mother liquor is 1-10%.

2. The method for preparing bromine according to claim 1, characterized in that, In step one, the sodium bromide is stirred for 30 minutes, and then hydrobromic acid is added and stirred for another 30 minutes.

3. The method for preparing bromine according to claim 1, characterized in that, The preheating temperature in step three is 50℃-70℃.

4. The method for preparing bromine according to claim 1, characterized in that, In step four, the temperature at the top of the bromine distillation tower is 85°C.

5. The method for preparing bromine according to claim 1, characterized in that, In step four, the ratio of the mass of chlorine to the sum of the masses of sodium bromide and hydrobromic acid in step one is 1:

2.

6. The method for preparing bromine according to claim 1, characterized in that, The concentration of the sodium bicarbonate solution in step five is 30%.

7. The method for preparing bromine according to claim 1, characterized in that, In step six, the pressure of the bromine water separation bottle is 0.15 MPa.

8. The method for preparing bromine according to claim 1, characterized in that, In step six, the temperature is maintained at 30°C.

Images