A method for extracting bromine from brine

Abstract

The present invention belongs to the technical field of inorganic substance preparation methods, and specifically provides a method for extracting bromine from brine, including S1: Acidification and oxidation pretreatment of brine; S2: Blowing out bromine molecules with air; S3: Absorbing with sulfur dioxide and fresh water; S4: Distilling and purifying bromine; S3 includes a method for adjusting the bromine concentration C in the finished liquid during the absorption process of sulfur dioxide and fresh water. S300: Using a high-pressure atomizing nozzle array with a pore diameter of 1.0 - 2.0 mm, and setting the nozzle spacing to match the cross-sectional area of the blowing and suction tower to form a three-dimensional atomization field; S301: Controlling the gas-liquid volume flow ratio in the absorption tower; S302: The high-pressure atomizing nozzles are equipped with a high-pressure pump group, and the high-pressure pump group can establish a dynamic pressure compensation model; S303: Real-time monitoring of the bromine concentration C in the finished liquid through an on-line concentration meter, and adjusting the fresh water flow rate in real time according to the bromine concentration C in the finished liquid, so as to control the bromine concentration in the finished liquid.

Description

Technical Field

[0001] The present invention relates to the technical field of inorganic substance preparation methods, and in particular to a method for extracting bromine from brine. Background Art

[0002] Bromine is a resource-dependent product and an important chemical raw material, which is widely used in fields such as high-efficiency flame retardants, refrigerants, petroleum, medicine, fuel intermediates, photosensitive materials, and chemical reagents. At present, there are the following several methods for extracting bromine from brine: steam distillation method, air blowing method, resin adsorption method, extraction method, and precipitation method.

[0003] The air blowing method includes an acid solution absorption method and an alkali solution absorption method. Among them, the acid solution absorption method is to add sulfur dioxide and fresh water in a blowing and suction tower during the extraction of bromine from brine to capture bromine molecules to form a finished solution of hydrobromic acid, and then perform distillation extraction.

[0004] In the industrial production process, the traditional control method of the sulfur dioxide reduction absorption process relies on a fixed flow rate adjustment mode or the experience intervention of operators, which is difficult to dynamically respond to the fluctuation of bromine concentration, and is likely to cause the over-dilution of the finished solution or the local crystallization due to too high concentration, affecting the subsequent distillation efficiency. Summary of the Invention

[0005] Aiming at the above defects, the present invention provides a method for extracting bromine from brine, which can reduce the consumption of fresh water and ensure the relative stability of the hydrobromic acid concentration at the same time.

[0006] To achieve the above object, the present invention provides the following technical solution: A method for extracting bromine from brine, comprising: S1: Acidification and oxidation pretreatment of brine, mixing brine with distillation waste liquid or dilute sulfuric acid, adjusting the pH to acidic, and then introducing chlorine gas for reaction;

[0007] S2: Blowing out bromine molecules, introducing the brine treated in S1 into a blowing tower for spraying, and blowing out through a blower to form bromine-containing air;

[0008] S3: Absorption of sulfur dioxide and fresh water, blowing the bromine-containing air into an absorption tower, and forming a finished solution including hydrobromic acid and sulfuric acid through contact with the sprayed sulfur dioxide gas and fresh water;

[0009] S4: Distillation and purification of bromine, introducing the finished solution generated in step S3 into a distillation tower, and introducing steam and chlorine gas for reaction to generate Br2 vapor and discharge it, and obtaining the finished bromine through condensation and separation;

[0010] The S3 includes a method for adjusting the bromine concentration C in the finished solution during the absorption of sulfur dioxide and fresh water:

[0011] S300: An array of high-pressure atomizing nozzles with an aperture of 1.0 - 2.0 mm is adopted, and the nozzle spacing is set to match the cross-sectional area of the blowing and suction tower to form a three-dimensional atomization field with a coverage rate of 85% - 95%;

[0012] S301: Control the gas-liquid volume flow ratio in the absorption tower within the range of 1:8 - 1:12;

[0013] S302: The high-pressure atomizing nozzles are equipped with a high-pressure pump group, and the high-pressure pump group can establish a dynamic pressure compensation model:

[0014] P = K×(Q / S) + ΔP

[0015] Where: P is the real-time regulation pressure (MPa), Q is the fresh water flow rate (m3 / h), S is the effective spraying area (m 2 ), K is the system resistance coefficient of 0.15 - 0.25, and ΔP is the pressure correction value of 0.05 - 0.12 MPa;

[0016] S303: The bromine concentration C in the finished liquid is monitored in real time through an on-line concentration meter, and the fresh water flow rate is adjusted in real time according to the bromine concentration C in the finished liquid, so as to control the bromine concentration C in the finished liquid: 60 kg / m³ ≤ C ≤ 85 kg / m³.

[0017] As a further improvement of the present invention, the control method for the bromine concentration C in S303 is:

[0018] When C < 60 kg / m³:

[0019] Start the throttle valve, and gradually reduce the fresh water flow rate in a gradient of 0.5% - 1.5% of the current flow reference value Q0 until the concentration rises above 60 kg / m³;

[0020] When 60 kg / m³ ≤ C ≤ 85 kg / m³:

[0021] Maintain the current flow rate unchanged, and the system is in a stable operation range to avoid fluctuations caused by frequent regulation;

[0022] When C > 85 kg / m³:

[0023] Link the proportional valve, and increase the fresh water flow rate in a gradient of 2% - 4% of the current flow reference value Q0 until the concentration drops below 85 kg / m³.

[0024] As a further improvement of the present invention, the adjustment period of the fresh water flow rate in S303 is 30 s.

[0025] As a further improvement of the present invention, if C continuously > 90 kg / m³ for more than 4 adjustment cycles in S303, a three-level acceleration adjustment is triggered, and the change gradient of the fresh water flow rate ΔQ = +0.06Q0 / time.

[0026] As a further improvement of the present invention, S303 further includes:

[0027] According to the change rate of bromine concentration dC / dt in the completion liquid, a non-linear compensation adjustment is performed on the change gradient of the fresh water flow rate ΔQ, specifically:

[0028] The calculation formula for the change rate of bromine concentration dC / dt in the completion liquid is:

[0029]

[0030] When C < 60 kg / m³ and dC / dt > 0, the change gradient of the fresh water flow rate ΔQ is reduced;

[0031] When C > 85 kg / m³ and dC / dt < 0, the change gradient of the fresh water flow rate ΔQ is increased.

[0032] As a further improvement of the present invention, in the non-linear compensation adjustment of the change gradient of the fresh water flow rate ΔQ, the calculation formula for the correction coefficient α is:

[0033]

[0034] The change gradient of the fresh water flow rate ΔQ is corrected by the correction coefficient α.

[0035] As a further improvement of the present invention, when C < 60 kg / m³ and dC / dt > 0, the calculation formula for the change gradient of the fresh water flow rate ΔQ is specifically:

[0036] 。

[0037] As a further improvement of the present invention, when C > 85 kg / m³ and dC / dt < 0, the calculation formula for the change gradient of the fresh water flow rate ΔQ is specifically:

[0038] 。

[0039] As a further improvement of the present invention, S301 further includes: generating a negative pressure difference of 150 - 250 Pa through the Venturi effect, so that the bromine vapor and the atomized liquid droplets form a vortex contact.

[0040] The beneficial effects of the present invention:

[0041] 1. Through the synergistic effect of the dynamic pressure compensation model and the Venturi negative pressure, the atomization pressure is matched with the flow rate change in real time, the atomization field coverage rate and droplet uniformity are maintained, the gas-liquid contact efficiency is enhanced, and the bromine escape is reduced.

[0042] 2. The bromine concentration is monitored in real time by an on-line concentration meter, and combined with the gradient adjustment mechanism, the concentration of the finished liquid is dynamically stabilized within a specified range, effectively avoiding the risk of excessive increase or crystallization caused by out-of-control concentration in the traditional process. At the same time, a non-linear compensation design is introduced, and the fresh water flow rate adjustment gradient is dynamically adjusted according to the concentration change rate (dC / dt), significantly improving the anti-disturbance ability of the system and avoiding the concentration fluctuation caused by adjustment lag. Specific embodiments

[0043] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below in conjunction with embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0044] The present invention provides a method for extracting bromine from brine, and the steps are as follows:

[0045] S1: Acidification and oxidation pretreatment of brine.

[0046] The brine (containing Br ions) is introduced into a static mixer and mixed with distillation waste liquid or dilute sulfuric acid to adjust the pH to acidic (2 < pH < 3). Chlorine gas (Cl2) is introduced into the acidified brine to oxidize bromide ions into free bromine molecules (Br2).

[0047] As a further explanation of this embodiment, the purpose of acidifying the brine in S1 is to avoid the hydrolysis loss of bromine in an alkaline environment during subsequent chlorine oxidation.

[0048] S2: Air stripping of bromine molecules.

[0049] The brine treated in S1 is sprayed down from the top of the stripping tower. At the same time, a blower blows air from the bottom of the tower, flowing countercurrently to the brine, and the free Br2 is stripped and blown out by the air to form bromine-containing air.

[0050] S3: Absorption by sulfur dioxide and fresh water.

[0051] The bromine-containing air is blown into the absorption tower from the top of the stripping tower and contacts the sprayed sulfur dioxide (SO2) gas and fresh water in a co-current manner. SO2 and Br2 undergo a reduction reaction in an acidic environment to form a finished liquid including hydrobromic acid (HBr) and sulfuric acid (H2SO4).

[0052] S4: Distillation and purification of bromine.

[0053] The finished liquid containing hydrobromic acid (HBr) and sulfuric acid (H₂SO₄) generated in step S3 is added from the top of the distillation column, and at the same time, steam and chlorine gas are introduced from the bottom of the column. The chlorine gas secondary oxidizes HBr to Br₂, generating Br₂ vapor. The Br₂ vapor is discharged from the top of the column, cooled to liquid bromine by a condenser, and then the moisture and impurities are removed through a separator, and finally the finished bromine is obtained.

[0054] As a further explanation of this embodiment, step S3 further includes a method for adjusting the bromine concentration C in the finished liquid during the sulfur dioxide and fresh water absorption process:

[0055] S300: An array of high-pressure atomizing nozzles with a pore diameter of 1.0 - 2.0 mm is used, and the nozzle spacing is set to match the cross-sectional area of the blowing and suction tower to form a three-dimensional atomization field with a coverage rate of 85 - 95%.

[0056] S301: Control the gas-liquid volume flow ratio in the absorption tower within the range of 1:8 - 1:12, and generate a negative pressure difference of 150 - 250 Pa through the Venturi effect to form a vortex contact between the bromine vapor and the atomized droplets.

[0057] S302: The high-pressure atomizing nozzles are equipped with a high-pressure pump group, and the high-pressure pump group can establish a dynamic pressure compensation model:

[0058] P = K×(Q / S) + ΔP

[0059] In the formula: P is the real-time regulated pressure (MPa), Q is the fresh water flow rate (m 3 / h), S is the effective spraying area (m 2 ), K is the system resistance coefficient (0.15 - 0.25), and ΔP is the pressure correction value (0.05 - 0.12 MPa).

[0060] S303: The bromine concentration C in the finished liquid is monitored in real time through an on-line concentration meter, and the fresh water flow rate is adjusted in real time according to the bromine concentration C in the finished liquid, so as to control the bromine concentration C in the finished liquid: 60 kg / m³ ≤ C ≤ 85 kg / m³.

[0061] When C < 60 kg / m³:

[0062] Start the throttle valve, and gradually reduce the fresh water flow rate in a gradient of 0.5% - 1.5% of the current flow rate reference value (Q0) (ΔQ = -0.005Q0 ~ -0.015Q0) until the concentration rises above 60 kg / m³.

[0063] Adjustment period: Detect once every 30 seconds, and the single adjustment amplitude does not exceed 1.5%.

[0064] When 60 kg / m³ ≤ C ≤ 85 kg / m³:

[0065] Keep the current flow rate unchanged, and the system is in a stable operating range to avoid fluctuations caused by frequent adjustments.

[0066] When C > 85 kg / m³:

[0067] Link the proportional valve and increase the fresh water flow rate in a gradient of 2% - 4% (ΔQ = +0.02Q0~+0.04Q0) until the concentration drops below 85 kg / m³.

[0068] Adjustment period: Detect once every 30 seconds, and the single - adjustment amplitude does not exceed 4%.

[0069] Emergency mode: If C continuously > 90 kg / m³ for more than 2 minutes, trigger the third - level acceleration adjustment (ΔQ = +0.06Q0 / time).

[0070] As a further explanation of this embodiment, S303 also includes non - linear compensation adjustment of the fresh water flow rate change gradient ΔQ according to the change rate of bromine concentration dC / dt in the finished liquid. Specifically:

[0071] Calculate the concentration change rate (dC / dt) through the continuous sampling data of the on - line concentration meter

[0072]

[0073] When dC / dt > 0, it means the concentration is rising.

[0074] When dC / dt < 0, it means the concentration is falling.

[0075] Then establish a mathematical model of the gradient correction coefficient (α).

[0076] The calculation formula of the correction coefficient α is:

[0077]

[0078] Specifically, through non - linear compensation design, the correction coefficient α corrects the fresh water flow rate change gradient ΔQ:

[0079] When C < 60 kg / m³ and dC / dt > 0, the concentration is rising rapidly, and it is necessary to slow down the reduction, reduce the fresh water flow rate change gradient ΔQ to avoid excessive rise of the finished liquid.

[0080]

[0081] When C > 85 kg / m³ and dC / dt < 0, the concentration is falling rapidly, and it is necessary to accelerate dilution, increase the fresh water flow rate change gradient ΔQ to prevent crystallization risk.

[0082] 。

[0083] Example 1

[0084] S1: Acidification and oxidation pretreatment of brine.

[0085] Introduce the brine (containing Br ions) into a static mixer, mix it with the distillation waste liquid or dilute sulfuric acid, and adjust the pH to 2.5. Then introduce chlorine gas (Cl2) into the acidified brine.

[0086] S2: Blowing out bromine molecules with air.

[0087] Spray the brine treated in S1 from the top of the blowing tower downwards. At the same time, a blower blows air from the bottom of the tower, flowing countercurrently to the brine, to form bromine-containing air.

[0088] S3: Absorption with sulfur dioxide and fresh water.

[0089] Blow the bromine-containing air from the top of the blowing tower into the absorption tower, and make it flow in the same direction as the sprayed sulfur dioxide (SO2) gas and fresh water for contact.

[0090] The device for spraying fresh water uses a high-pressure atomizing nozzle array with a pore diameter of 1.0 mm, and is set with the nozzle spacing matching the cross-sectional area of the blowing and sucking tower to form a three-dimensional atomization field with a coverage rate of 85%.

[0091] Taking the reference flow rate Q0 of fresh water as 12 m 3 / h, inject fresh water into the absorption tower, and control the gas-liquid volume flow ratio in the absorption tower at 1:12 to obtain the flow rate Q q0 of the gas SO2 as:

[0092] Q q0 =Q0×1 / 12 = 1 m 3 / h

[0093] Control the negative pressure difference generated by the Venturi effect inside the absorption tower to be 150 Pa.

[0094] At the same time, it is known that the effective spraying area S of the absorption tower is 7 m 2 , and taking the system resistance absorption K as 0.25 and the pressure correction value ΔP as 0.12 MPa, the working pressure P0 of the high-pressure pump group can be obtained through calculation as:

[0095] P0 = K×(Q0 / S) + ΔP = 0.25×(12 / 7) + 0.12 ≈ 0.549 Pa

[0096] Under this working condition, according to the detection period Δt = 30 s, the bromine concentration in the finished liquid is detected in real time by an on-line concentration meter.

[0097] After a certain periodic detection, it is found that the bromine concentration C0 in the finished liquid = 58 kg / m³ (lower than the lower limit of 60 kg / m³);

[0098] The system triggers the regulation mechanism of bromine concentration C:

[0099] 1. First regulation (t = 0).

[0100] Concentration change:

[0101] Initial concentration C0 = 58 kg / m³, triggering the regulation condition (C0 < 60 kg / m³).

[0102] Regulation action: Adopt the reference gradient ΔQ1 = -1.2%×Q0 = -0.144 m³ / h

[0103] Q1 = Q0 + ΔQ1 = 12 - 0.144 = 11.856 m³ / h.

[0104] At this time, the flow rate Q of SO2 q1 is:

[0105] Q q1 = Q1×1 / 12 = 11.856×1 / 12 = 0.988 m 3 / h

[0106] Through calculation, the working pressure P1 of the high-pressure pump group is:

[0107] P1 = K×(Q1 / S) + ΔP = 0.25×(11.856 / 7) + 0.12 ≈ 0.543 Pa.

[0108] 2. Second detection and regulation (t = 30 seconds).

[0109] Concentration change:

[0110] After the first regulation, it is detected that the bromine concentration in the finished liquid changes to C1 = 59 kg / m³, C1 < 60 kg / m³,

[0111] Regulation action:

[0112] Calculate the concentration change rate

[0113]

[0114] Gradient correction

[0115]

[0116] Since the concentration change rate dC / dt > 0 (the concentration is on the rise), but C1 is still below the lower limit, it is necessary to suppress excessive reduction:

[0117]

[0118] Actual regulation:

[0119] To prevent response lag, the actual adjustment quantity Q2 should be slightly higher than the calculated value. Therefore, ΔQ2 should be slightly less than the calculated value (but ΔQ2 should not exceed the variation range and should always be between -0.005Q0 and -0.015Q0).

[0120] Take the safety value ΔQ2 = -0.8%×Q0 = -0.096m³ / h

[0121] Q2 = Q1 + ΔQ2 = 11.76m³ / h.

[0122] At this time, the flow rate Q of SO2 q2 is:

[0123] Q q2 = Q2×1 / 12 = 0.98m 3 / h

[0124] Through calculation, the working pressure P2 of the high-pressure pump set is:

[0125] P2 = K×(Q2 / S) + ΔP = 0.25×(11.76 / 7) + 0.12 = 0.54Pa.

[0126] 3. The third detection and adjustment.

[0127] Concentration change: The detected concentration C3 = 61kg / m³, entering the safe zone (60 - 85kg / m³), stop adjusting the fresh water flow rate.

[0128] S4: Distill and purify bromine.

[0129] Add the finished liquid containing hydrobromic acid (HBr) and sulfuric acid (H2SO4) generated in step S3 from the top of the distillation column, and at the same time introduce steam and chlorine from the bottom of the column. Chlorine re-oxidizes HBr to Br2, generating Br2 vapor. The Br2 vapor is discharged from the top of the column, cooled to liquid bromine by a condenser, and then the moisture and impurities are removed through a separator to finally obtain the finished bromine.

[0130] Example 2

[0131] S1: Acidification and oxidation pretreatment of brine.

[0132] Pass the brine (containing Br ions) into a static mixer, mix it with distillation waste liquid or dilute sulfuric acid, and adjust the pH to 2.5. Pass chlorine (Cl2) into the acidified brine.

[0133] S2: Blow out bromine molecules with air.

[0134] Spray the brine treated in S1 down from the top of the blowing tower. At the same time, a blower blows air from the bottom of the tower, flowing countercurrently to the brine, to form bromine-containing air.

[0135] S3: Sulfur dioxide and fresh water absorption.

[0136] The bromine-containing air is blown into the absorption tower from the top of the stripping tower and contacts the sprayed sulfur dioxide (SO2) gas and fresh water in a co-current manner.

[0137] The device for spraying fresh water uses a high-pressure atomizing nozzle array with a pore diameter of 2.0 mm, and is configured with the nozzle spacing matching the cross-sectional area of the air blowing and suction tower to form a three-dimensional atomization field with a coverage rate of 95%.

[0138] Taking the reference flow rate Q0 of fresh water as 12 m 3 / h, fresh water is injected into the absorption tower, and the gas-liquid volume flow ratio in the absorption tower is controlled at 1:8 to obtain the flow rate Q q0 of gas SO2 as:

[0139] Q q0 = Q0 × 1 / 8 = 1.5 m 3 / h

[0140] The negative pressure difference generated inside the absorption tower through the Venturi effect is controlled at 250 Pa.

[0141] At the same time, it is known that the effective spraying area S of the absorption tower is 10 m 2 , and taking the system resistance absorption K as 0.15 and the pressure correction value ΔP as 0.05 MPa, the working pressure P0 of the high-pressure pump group can be obtained through calculation as:

[0142] P0 = K × (Q0 / S) + ΔP = 0.15 × (12 / 10) + 0.05 = 0.23 Pa

[0143] Under this working condition, according to the detection period Δt = 30 s, the bromine concentration in the finished liquid is detected in real time by an on-line concentration meter.

[0144] After a certain periodic detection, it is found that the bromine concentration C0 in the finished liquid = 88 kg / m³ (higher than the upper limit of 85 kg / m³);

[0145] 1. First adjustment (t = 0).

[0146] The concentration becomes the initial concentration C0 = 88 kg / m³, triggering the adjustment condition (C0 > 85 kg / m³).

[0147] Adjustment action: Adopt the reference gradient ΔQ1 = 3% × Q0 = 0.36 m³ / h,

[0148] Q1 = Q0 + ΔQ1 = 12 + 0.36 = 12.36 m³ / h

[0149] At this time, the flow rate Q of SO2 q1 is:

[0150] Qq1 = Q1×1 / 8 = 12.36×1 / 8 = 1.545 m 3 / h

[0151] The working pressure P1 of the high-pressure pump set can be obtained by calculation as follows:

[0152] P1 = K×(Q1 / S) + ΔP = 0.15×(12.36 / 10) + 0.05 ≈ 0.235 Pa.

[0153] 2. Second detection and adjustment (t = 30 seconds).

[0154] Concentration change:

[0155] After the first adjustment, the change in the bromine concentration in the finished liquid is detected as C 21 = 86 kg / m³, C1 > 85 kg / m³,

[0156] Adjustment action:

[0157] Calculate the concentration change rate

[0158]

[0159] Gradient correction

[0160]

[0161] Since the concentration change rate dC / dt < 0 (the concentration is decreasing), but C1 is still greater than the upper limit, to prevent crystallization, it is necessary to accelerate dilution:

[0162]

[0163] Actual adjustment:

[0164] To prevent response lag, the actual adjustment amount Q2 should be slightly higher than the calculated value. Therefore, ΔQ2 should be slightly higher than the calculated value (but ΔQ2 should not exceed the change range and should always be between +0.02Q0 and +0.04Q0),

[0165] Take the safety value ΔQ2 = 3.5%×Q0 = 0.42 m³ / h

[0166] Q2 = Q1 + ΔQ2 = 12.36 + 0.42 = 12.78 m³ / h.

[0167] At this time, the flow rate Q of SO2 q2 is:

[0168] Q q2 = Q2×1 / 8 ≈ 1.60 m 3 / h

[0169] By calculation, the working pressure P2 of the high-pressure pump set is as follows:

[0170] P2 = K×(Q2 / S) + ΔP = 0.15×(12.78 / 10) + 0.05 ≈ 0.242 Pa.

[0171] 3. Third detection and adjustment.

[0172] Concentration change: The detected concentration C3 = 84 kg / m³, entering the safe zone (60 - 85 kg / m³), stop adjusting the fresh water flow rate.

[0173] S4: Distill and purify bromine.

[0174] Add the finished liquid containing hydrobromic acid (HBr) and sulfuric acid (H2SO4) generated in step S3 from the top of the distillation column, and at the same time introduce steam and chlorine from the bottom of the column. Chlorine re-oxidizes HBr to Br2, generating Br2 vapor. The Br2 vapor is discharged from the top of the column, cooled to liquid bromine by a condenser, and then the water and impurities are removed through a separator to finally obtain the finished bromine.

[0175] The above is only the preferred implementation mode of the present invention. The protection scope of the present invention is not limited to the above implementation measures. All technical solutions falling within the idea of the present invention belong to the protection scope of the present invention. It should be pointed out that for those of ordinary skill in the art, several improvements and refinements made without departing from the principle of the present invention should also be regarded as within the protection scope of the present invention.

Claims

1. A method for extracting bromine from brine, characterized in that, Including: S1: Acidification and oxidation pretreatment of brine. Mix the brine with distillation waste liquid or dilute sulfuric acid, adjust the pH to acidic, and then introduce chlorine gas for reaction. S2: Blowing out bromine molecules with air. Introduce the brine treated in S1 into the blowing tower for spraying, and blow it out through a blower to form bromine-containing air. S3: Absorption with sulfur dioxide and fresh water. Blow the bromine-containing air into the absorption tower, and through contact with the sprayed sulfur dioxide gas and fresh water, form a finished liquid including hydrobromic acid and sulfuric acid. S4: Distillation and purification of bromine. Introduce the finished liquid generated in step S3 into the distillation tower, and introduce steam and chlorine gas for reaction to generate Br2 vapor and discharge it. Obtain the finished bromine through condensation and separation. The S3 includes a method for adjusting the bromine concentration C in the finished liquid during the absorption process with sulfur dioxide and fresh water: S300: Adopt a high-pressure atomizing nozzle array with a pore diameter of 1.0 - 2.0 mm, and set the nozzle spacing to match the cross-sectional area of the blowing and sucking tower to form a three-dimensional atomizing field with a coverage rate of 85% - 95%. S301: Control the gas-liquid volume flow ratio in the absorption tower within the range of 1:8 - 1:

12. S302: The high-pressure atomizing nozzle is equipped with a high-pressure pump group, and the high-pressure pump group establishes a dynamic pressure compensation model: P = K×(Q / S) + ΔP Where: P is the real-time regulated pressure (MPa), Q is the fresh water flow rate (m 3 / h), S is the effective spray area (m 2 ), K is the system resistance coefficient of 0.15 - 0.25, and ΔP is the pressure correction value of 0.05 - 0.12 MPa; S303: Real-time monitor the bromine concentration C in the finished liquid through an on-line concentration meter, and adjust the fresh water flow rate in real time according to the bromine concentration C in the finished liquid, so as to control the bromine concentration C in the finished liquid: 60 kg / m³ ≤ C ≤ 85 kg / m³.

2. The method for extracting bromine from brine according to claim 1, wherein, The control method for the bromine concentration C in the S303 is as follows: When C < 60 kg / m³: Start the throttle valve, and gradually reduce the fresh water flow rate in gradients of 0.5% - 1.5% of the current flow reference value Q0 until the concentration rises above 60 kg / m³. When 60 kg / m³ ≤ C ≤ 85 kg / m³: Maintain the current flow rate unchanged, and the system is in a stable operation range to avoid fluctuations caused by frequent adjustment. When C > 85 kg / m³: Link the proportional valve, and increase the fresh water flow rate in gradients of 2% - 4% of the current flow reference value Q0 until the concentration drops below 85 kg / m³.

3. The method for extracting bromine from brine according to claim 2, characterized in that, The adjustment period of the fresh water flow rate in the S303 is 30 s.

4. The method for extracting bromine from brine according to claim 3, characterized in that In the S303, if C continuously > 90 kg / m³ for more than 4 adjustment periods, trigger a three-level acceleration to adjust the fresh water flow rate change gradient ΔQ = +0.06Q0 / time.

5. The method for extracting bromine from brine according to claim 2, wherein The S303 also includes: According to the change rate dC / dt of the bromine concentration in the finished liquid, perform non-linear compensation adjustment on the fresh water flow rate change gradient ΔQ. Specifically: The calculation formula for the change rate dC / dt of the bromine concentration in the finished liquid is: When C < 60 kg / m³ and dC / dt > 0, reduce the fresh water flow rate change gradient ΔQ; When C > 85 kg / m³ and dC / dt < 0, increase the fresh water flow rate change gradient ΔQ.

6. The method for extracting bromine from brine according to claim 5, wherein In the non-linear compensation adjustment of the fresh water flow rate change gradient ΔQ, the calculation formula for the correction coefficient α is: Correct the fresh water flow rate change gradient ΔQ through the correction coefficient α.

7. The method for extracting bromine from brine according to claim 6, wherein When C < 60 kg / m³ and dC / dt > 0, the specific calculation formula for the change gradient ΔQ of the fresh water flow rate is as follows: 。 8. The method for extracting bromine from brine according to claim 6, characterized in that, When C > 85 kg / m³ and dC / dt < 0, the specific calculation formula for the change gradient ΔQ of the fresh water flow rate is as follows: 。 9. The method for extracting bromine from brine according to claim 1, wherein, The S301 further includes: generating a negative pressure difference of 150 - 250 Pa through the Venturi effect, so that the bromine vapor and the atomized droplets form a vortex contact.

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