A device and method for treating sodium bromide wastewater in a photoinitiator production process

Abstract

This invention relates to a treatment device and method for sodium bromide wastewater during photoinitiator production. The treatment device includes a distillation acidification kettle, a filter, an oxidative distillation kettle, a condenser, and a separator, arranged sequentially. The treatment device can separate bromine from organic impurities in sodium bromide wastewater and obtain bromine that can be used as a raw material for photoinitiator preparation, thus realizing the resource utilization of sodium bromide wastewater and reducing treatment costs. It solves the problems of high difficulty and high cost in treating sodium bromide wastewater using traditional processes.

Description

Technical Field

[0001] This invention belongs to the field of photoinitiators and relates to a treatment device and method for sodium bromide wastewater in the process of photoinitiator production. Background Technology

[0002] Photoinitiators are compounds that can absorb energy of a certain wavelength in the ultraviolet or visible light region, generate free radicals, cations, etc., and thus initiate monomer polymerization, cross-linking and curing.

[0003] α-Aminoacetophenone photoinitiators possess advantages such as good thermal stability, long shelf life, good solubility, light color, good anti-yellowing properties, fast photocuring speed, and good deep curing performance. They are particularly suitable for colored systems and have been widely used in the UV curing field, including in photocurable coatings, inks, and photoresists. Commercially available products include 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone and 2-(4-methylbenzyl)-2-dimethylamino-1-(4-morpholinophenyl)butanone, etc.

[0004] CN105384707A discloses a method for preparing α-aminoacetophenone-based photoinitiators. The preparation process includes bromination, dimethylamine substitution, benzyl chloride or methylbenzyl chloride substitution, and morpholine substitution reactions. In the above preparation process, the dimethylamine substitution reaction uses dimethylamine to replace bromine, which generates a large amount of sodium bromide wastewater. The salinity of this wastewater is extremely high (>100,000 mg / L), making it extremely difficult to treat. Existing technologies generally recover a mixture of sodium bromide and organic impurities from the wastewater to reduce the salinity before it enters the wastewater treatment process. However, due to the complex composition of the distilled solids (mainly sodium bromide), it can only be treated as hazardous waste, resulting in high treatment costs. Taking the production of 2-benzyl-2-dimethylamino-1-(4-morpholinephenyl)butanone as an example, the treatment cost of sodium bromide wastewater accounts for about 5% of the total cost.

[0005] Therefore, it is still of great significance to develop a resource-based treatment device for sodium bromide wastewater that can effectively recover bromine from wastewater and has a low cost. Summary of the Invention

[0006] The purpose of this invention is to provide a treatment device and method for sodium bromide wastewater during the production of photoinitiators. The treatment device includes a distillation acidification kettle, a filter, an oxidative distillation kettle, a condenser, and a separator arranged in sequence. The above-mentioned treatment device can separate bromine from organic impurities in sodium bromide wastewater and obtain bromine that can be used as a raw material for the preparation of photoinitiators, realizing the resource utilization of sodium bromide wastewater, and the treatment cost is low. It solves the problems of high difficulty and high cost in the treatment of sodium bromide wastewater by traditional processes.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a treatment device for sodium bromide wastewater in the production process of photoinitiators, including a distillation acidification kettle, a filter, an oxidative distillation kettle, a condenser and a separator;

[0009] The distillation acidification vessel is equipped with a sodium bromide wastewater inlet, an adsorbent inlet, and a sulfuric acid inlet, and the bottom of the distillation acidification vessel is equipped with a mixed liquid outlet.

[0010] The filter is provided with a liquid inlet, which is connected to the liquid outlet; the bottom of the filter is provided with a clear liquid outlet.

[0011] The oxidative distillation vessel is provided with a clear liquid inlet, which is connected to the clear liquid outlet; the oxidative distillation vessel is also provided with a hydrogen peroxide inlet and a steam outlet.

[0012] The condenser is provided with a steam inlet, which is connected to the steam outlet; the condenser is provided with a condensate outlet, which is connected to the separator.

[0013] The separator is equipped with a bromine outlet.

[0014] α-Aminoacetophenone photoinitiators, taking photoinitiator 369 and photoinitiator 379 as examples, generally involve bromination and dimethylamine substitution reactions during their preparation. After the dimethylamine substitution reaction is completed, the substituted bromine is converted into sodium bromide and dissolved in the aqueous phase, forming sodium bromide wastewater. The salinity of the above-mentioned sodium bromide wastewater is extremely high (>100,000 mg / L), making it extremely difficult to treat. Existing technologies generally use distillation to remove a mixture of sodium bromide and organic impurities. The mixture has a complex composition, mainly sodium bromide, and is treated as hazardous waste, resulting in high treatment costs. To address the above problems, this invention provides a resource-based treatment device and method for sodium bromide wastewater that can effectively recover bromine from the wastewater and has a low cost.

[0015] This invention, through compositional analysis of sodium bromide wastewater, reveals that the main component is sodium bromide, along with some organic impurities. Existing processes struggle to separate sodium bromide from the mixture. However, this invention utilizes a specific treatment device to convert sodium bromide in the wastewater into valuable bromine, thus turning waste into treasure and increasing added value. This solves the wastewater treatment problem, saves on the treatment costs of the wastewater and the mixture of sodium bromide and organic impurities, reduces production costs, and allows the bromine obtained from the wastewater to be recycled for photoinitiator preparation, forming a circular economy. This also saves on raw material procurement costs and enhances the competitiveness of the company's products.

[0016] The processing device of this invention includes a distillation acidification kettle, a filter, an oxidative distillation kettle, a condenser, and a separator arranged in sequence. The distillation acidification kettle and the filter are used to concentrate and acidify sodium bromide wastewater and remove some organic impurities. During operation, sodium bromide wastewater and a specific adsorbent are added to the distillation acidification kettle through the sodium bromide wastewater inlet and the adsorbent inlet, respectively. Vacuum distillation is initiated until sodium bromide solid precipitates. Then, sulfuric acid is added through the sulfuric acid inlet, the mixture is stirred, and the mixture is discharged through the mixture outlet. The mixed liquid is added to a filter through the inlet to remove the adsorbent, resulting in an acidified and preliminarily purified clear liquid. An oxidative distillation kettle, condenser, and separator are used to oxidize bromide ions to bromine and distill off a mixed vapor of bromine and water. After condensation in the condenser, the bromine product is separated in the separator. During operation, the acidified and preliminarily purified clear liquid is added to the oxidative distillation kettle through the clear liquid inlet, and hydrogen peroxide is added through the hydrogen peroxide inlet. The reaction proceeds, and a mixed vapor of bromine and water is distilled off. The bromine is then separated through the condenser and separator. This invention enables the effective recovery of bromine from sodium bromide wastewater, and the obtained bromine can be reused in the bromination reaction for preparing α-aminoacetophenone photoinitiators, achieving bromine recycling and reducing raw material procurement costs, as well as the treatment costs of high-salinity wastewater.

[0017] The processing device of this invention achieves the separation of bromine from organic impurities through adsorption, oxidation reaction (converting sodium bromide into bromine) combined with distillation, thereby realizing the resource recovery of bromine. The obtained bromine can be used in the photoinitiator preparation process, forming a circular economy of sodium bromide-bromine-sodium bromide. Moreover, the above process consumes only a small amount of hydrogen peroxide and sulfuric acid. Compared with the traditional treatment method of evaporating and desalinating sodium bromide wastewater to obtain a mixture of sodium bromide and organic impurities and then treating the mixture as hazardous waste, the production cost is greatly reduced.

[0018] The treatment method described in this invention solves the problems of difficult and costly treatment of high-salt sodium bromide wastewater and the resulting hazardous waste. The treatment process consumes only a small amount of inexpensive hydrogen peroxide and sulfuric acid, which not only reduces treatment costs but also reduces the amount of bromine to be purchased, thereby significantly reducing production costs.

[0019] Preferably, the processing apparatus further includes a sulfuric acid feeding tank, the height of which is higher than that of the distillation acidification vessel. The sulfuric acid feeding tank is used to store and add sulfuric acid to the distillation acidification vessel, and this positioning facilitates the delivery of sulfuric acid.

[0020] Preferably, the bottom of the sulfuric acid feeding tank is provided with a sulfuric acid outlet, which is connected to the sulfuric acid feeding port.

[0021] Preferably, the sulfuric acid outlet is equipped with a valve. This valve at the sulfuric acid outlet increases the controllability of the sulfuric acid feeding process.

[0022] Preferably, a flow regulating valve is provided at the sulfuric acid inlet.

[0023] During the operation of the processing device described in this invention, it is necessary to control the rate at which sulfuric acid is added. It is preferable to use a slow dripping method. A flow regulating valve is provided here to control the dripping rate of sulfuric acid.

[0024] Preferably, a stirring paddle is provided inside the distillation acidification vessel, and a temperature control sleeve is provided outside the distillation acidification vessel; the temperature control sleeve has the dual function of heating and cooling, and can be arranged in a cooling water coil and a steam coil; during the operation of the above-mentioned treatment device, the vacuum distillation process of the distillation acidification vessel requires heating and temperature control, while the process of adding sulfuric acid may release heat, so cooling and temperature control are required, thereby ensuring that the distillation and acidification processes proceed stably.

[0025] Preferably, the distillation acidification vessel is provided with an exhaust port; preferably, the exhaust port is connected to an external condenser, a liquid storage tank and a vacuum pump, the external condenser is used to condense the distilled vapor to obtain a liquid phase; the liquid storage tank is used to receive and store the condensate of the distilled vapor in the distillation acidification vessel, and the vacuum pump is used to achieve vacuum distillation and improve distillation efficiency.

[0026] Preferably, the distillation acidification vessel is equipped with a sight glass; the sulfuric acid addition rate needs to be controlled during the addition of sulfuric acid, and the sight glass facilitates the observation of the situation inside the vessel; during the sulfuric acid dripping process, the liquid situation inside the vessel can be observed through the sight glass. If foaming is violent or the temperature rises violently, the dripping rate can be reduced. If this cannot be reduced, the dripping should be stopped until there is no foam and then the dripping can continue.

[0027] Preferably, the oxidative distillation vessel is equipped with a stirring paddle, and a temperature control sleeve is provided outside the oxidative distillation vessel; the temperature control sleeve has a dual function of heating and cooling, and can be arranged in a cooling water coil and a steam coil; during the operation of the device, heat is released during the addition of hydrogen peroxide to the oxidative distillation vessel, at which time cooling and temperature control are required; after the hydrogen peroxide is added, the temperature needs to be further increased to distill out bromine, at which time heating and temperature control are required.

[0028] Preferably, the height of the distillation acidification vessel is higher than the height of the filter; this positioning facilitates material transport.

[0029] Preferably, the filter includes a tank and a horizontally arranged filter layer inside the tank, with a discharge port on the tank corresponding to the position of the filter layer. During operation of the processing device of the present invention, when the mixed liquid obtained from the distillation acidification kettle flows through the filter layer inside the filter tank, the solid adsorbent and impurities remain on the filter layer, thereby obtaining a clear liquid. The filtered material on the filter layer can be discharged through the discharge port.

[0030] Preferably, the processing device further includes a hydrogen peroxide feeding tank, the height of which is higher than the height of the oxidative distillation kettle, and a hydrogen peroxide outlet is provided on the hydrogen peroxide feeding tank, which is connected to the hydrogen peroxide filling port; a flow regulating valve is provided at the hydrogen peroxide filling port; the above configuration facilitates the control of the hydrogen peroxide feeding process.

[0031] Preferably, a sight glass is provided at the condensate outlet of the condenser.

[0032] A sight glass is installed here to observe the flow rate of the condensate, thereby adjusting the drip rate of the hydrogen peroxide. When the condensate flow rate is too high, the flow rate of the hydrogen peroxide is reduced by the flow regulating valve; when the condensate flow rate is too low, the flow rate of the hydrogen peroxide is increased by the flow regulating valve.

[0033] Preferably, the separator is provided with a condensate inlet and a non-condensable gas outlet; the condensate inlet is connected to the condensate outlet.

[0034] In this invention, the separator is used to separate bromine and water. The vapors of bromine and water obtained by distillation are condensed by a condenser to obtain condensate, which is then added to the separator through the condensate inlet for separation. Non-condensable gas is discharged through the non-condensable gas outlet.

[0035] Preferably, the processing device further includes a bromine storage tank, and the bromine outlet on the separator is connected to the bromine storage tank. In this invention, after separation in the separator, an upper aqueous phase and a lower bromine phase are obtained. The lower bromine phase is discharged from the bromine outlet and enters the bromine storage tank for storage.

[0036] Preferably, the processing device further includes a neutralization reaction vessel, the oxidative distillation vessel is provided with a distillation residue outlet, the distillation residue outlet is connected to the neutralization reaction vessel; the neutralization reaction vessel is provided with a liquid alkali inlet, and the neutralization reaction vessel is provided with a neutralization liquid outlet.

[0037] Preferably, a temperature control sleeve is provided outside the neutralization reactor, and a stirring paddle is provided inside the neutralization reactor.

[0038] In this invention, after the vapors of bromine and water are distilled out in the oxidative distillation vessel, the remaining liquid phase contains unreacted acid. To facilitate treatment, liquid alkali is added to the neutralization reaction vessel to neutralize the acid, resulting in a sodium sulfate solution, which can then be used as industrial wastewater for treatment.

[0039] Secondly, the present invention provides a method for treating sodium bromide wastewater during the production of photoinitiators, wherein the method employs the sodium bromide wastewater treatment apparatus described in the first aspect of the photoinitiator production process.

[0040] Preferably, the method for treating sodium bromide wastewater during the photoinitiator production process includes the following steps:

[0041] (1) Sodium bromide wastewater and adsorbent are added to the distillation acidification kettle through the sodium bromide wastewater inlet and the adsorbent feed inlet, respectively, and distilled under reduced pressure until sodium bromide precipitates. Then, sulfuric acid is added through the sulfuric acid inlet and mixed to obtain a mixed solution.

[0042] (2) The mixture in step (1) is discharged from the mixture outlet and enters the filter through the mixture inlet for filtration. The filtrate is discharged from the clear liquid outlet and added to the oxidative distillation kettle through the clear liquid inlet. Hydrogen peroxide is added through the hydrogen peroxide inlet to carry out the reaction. The vapors of bromine and water are distilled out, discharged from the steam outlet and entered into the condenser through the steam inlet. After condensation, the condensate is obtained, discharged from the condensate outlet and entered into the separator. After separation, the bromine is discharged from the bromine outlet.

[0043] The treatment method of this invention includes the steps of distillation and concentration in the presence of an adsorbent, sulfuric acid acidification, filtration to remove the adsorbent, hydrogen peroxide oxidation, distillation, condensation, and collection of bromine. These operations effectively separate bromine from organic impurities, thereby enabling the resource utilization of sodium bromide wastewater. The obtained bromine can be used for photoinitiator preparation, achieving a circular economy of sodium bromide → bromine → sodium bromide, reducing the procurement cost of raw material bromine. Furthermore, the above treatment method consumes only a small amount of hydrogen peroxide and sulfuric acid, resulting in low treatment costs. It solves the problems of difficult and costly treatment of sodium bromide wastewater.

[0044] The adsorbent in this invention has two functions: first, to adsorb impurities, including organic and mechanical impurities; and second, to aid filtration and improve the filtration effect.

[0045] Preferably, the sodium bromide wastewater is sodium bromide wastewater generated during the preparation of α-aminoacetophenone photoinitiators.

[0046] The α-aminoacetophenone photoinitiators mentioned here include 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone (photoinitiator 369) and 2-(4-methylbenzyl)-2-dimethylamino-1-(4-morpholinophenyl)butanone (photoinitiator 379).

[0047] Preferably, the adsorbent in step (1) is selected from any one or a combination of at least two of diatomaceous earth, activated carbon powder or resin.

[0048] Preferably, in step (1), the mass ratio of sodium bromide wastewater to adsorbent is 150 to 250:1, for example, 160:1, 170:1, 180:1, 190:1, 200:1, 210:1, 220:1, 230:1 or 240:1.

[0049] Preferably, the temperature of vacuum distillation in step (1) is 80℃~90℃, for example 81℃, 82℃, 83℃, 84℃, 85℃, 86℃, 87℃, 88℃ or 89℃.

[0050] Preferably, the mass of the remaining solution at the end of the vacuum distillation in step (1) is 0.4 to 0.6 times the mass of the sodium bromide wastewater, for example, 0.42, 0.45, 0.48, 0.5, 0.52, 0.55 or 0.58.

[0051] Preferably, sulfuric acid is added dropwise in step (1).

[0052] In this invention, the distillation acidification vessel is kept at atmospheric pressure during the addition of sulfuric acid, and the sulfuric acid is slowly added. At the same time, the liquid condition in the vessel needs to be observed through a sight glass during the addition process. If foaming is violent or the temperature rises violently, the addition rate can be reduced. If the problem cannot be alleviated, the addition should be stopped until there is no more foam and then the addition can continue.

[0053] Preferably, the temperature is controlled to ≤80°C during the addition of sulfuric acid in step (1), for example, 40°C, 50°C, 60°C or 70°C.

[0054] Preferably, the mass ratio of H2SO4 in sulfuric acid to sodium bromide wastewater added in step (1) is 0.35 to 0.55:1, for example, 0.36:1, 0.38:1, 0.4:1, 0.42:1, 0.45:1, 0.48:1, 0.5:1 or 0.52:1, and more preferably 0.4 to 0.45:1.

[0055] Preferably, the concentration of sulfuric acid in step (1) is 20% to 40%, such as 22%, 25%, 28%, 30%, 32%, 35%, or 38%, and more preferably 25% to 30%.

[0056] Preferably, the temperature is controlled at 40°C to 60°C during the mixing process in step (1), for example, 45°C, 50°C or 55°C.

[0057] Preferably, the sulfuric acid in step (1) is selected from waste sulfuric acid generated during the production of α-aminoacetophenone photoinitiators.

[0058] In the production process of α-aminoacetophenone photoinitiators, concentrated sulfuric acid is used to oxidize bromine in the bromination reaction to increase the utilization rate of bromine. The sulfuric acid is in excess. After the bromination reaction is completed, the aqueous phase obtained by separation contains sulfuric acid. The waste sulfuric acid can be used to acidify sodium bromide wastewater, thereby realizing the resource utilization of waste sulfuric acid and further reducing process costs.

[0059] Preferably, hydrogen peroxide is added dropwise in step (2);

[0060] Preferably, the mass ratio of H2O2 added to hydrogen peroxide in step (2) to the mass of sodium bromide wastewater in step (1) is 15% to 30%, for example, 18%, 20%, 22%, 25% or 28%.

[0061] Preferably, the concentration of hydrogen peroxide in step (2) is 20% to 60%, such as 25%, 30%, 35%, 40%, 45%, 50% or 55%, and more preferably 30% to 50%.

[0062] Preferably, the temperature is controlled to ≤80℃ during the addition of hydrogen peroxide in step (2), such as 60℃, 65℃, 70℃ or 75℃, preferably 60℃~80℃, and more preferably 75℃~80℃.

[0063] Preferably, distillation is carried out during the addition of hydrogen peroxide in step (2).

[0064] Preferably, after hydrogen peroxide is added in step (2), the distillation temperature is controlled to 95℃~105℃, such as 96℃, 97℃, 98℃, 99℃, 100℃, 101℃, 102℃, 103℃ or 104℃.

[0065] Preferably, after distillation is completed in step (2), the remaining liquid phase after distillation is discharged from the distillation residue outlet and enters the neutralization reaction vessel, and liquid alkali is added from the liquid alkali inlet to carry out the neutralization reaction, so as to obtain the neutralized liquid.

[0066] Preferably, the temperature is controlled to ≤80℃ during the neutralization process of adding liquid alkali, such as 50℃, 55℃, 60℃, 65℃, 70℃ or 75℃.

[0067] Preferably, the endpoint of neutralization by adding liquid alkali is reached when the pH of the solution is 7 to 8, such as 7.1, 7.2, 7.3, 7.4, 7.5, 7.6, 7.7, 7.8 or 7.9.

[0068] This invention, based on the concept of turning waste into treasure, transforms high-salinity wastewater into reaction raw materials through resource utilization, achieving a circular economy of sodium bromide → bromine → sodium bromide. Traditional wastewater treatment methods, through distillation and desalination, yield a mixture of sodium bromide and organic impurities. This mixture is complex in composition, and the sodium bromide and organic impurities are difficult to separate, making it unsuitable for sale as a byproduct and only suitable for hazardous waste disposal. This invention, through a specific device, converts sodium bromide into bromine, while the organic impurities partially do not react with hydrogen peroxide. Even if a small amount of impurities reacts with hydrogen peroxide, the organic impurities cannot be vaporized and distilled off during the distillation process like bromine. This not only solves the problem of separating organic impurities and sodium bromide but also utilizes waste sulfuric acid generated during the preparation of photoinitiators in the bromine production process, further reducing waste generation. Moreover, the treatment method described in this invention consumes only a small amount of inexpensive hydrogen peroxide and sulfuric acid, eliminating the treatment costs of high-salinity wastewater and hazardous waste, reducing the procurement of bromine raw materials, and thus significantly lowering production costs.

[0069] Compared with the prior art, the present invention has the following beneficial effects:

[0070] (1) The treatment device described in this invention can separate bromine from organic impurities in sodium bromide wastewater and convert sodium bromide into bromine, thereby realizing the resource utilization of bromine in sodium bromide wastewater; it avoids the problem that the traditional process requires distilling out a mixture of sodium bromide and organic impurities and treating it as hazardous waste, which is costly, and realizes turning waste into treasure;

[0071] (2) The processing device described in this invention consumes only a small amount of inexpensive hydrogen peroxide and sulfuric acid during operation, and the obtained bromine can be recycled for the preparation of photoinitiators, which reduces the amount of bromine raw materials purchased, thereby reducing production costs and enhancing the competitiveness of the products.

[0072] Instruction manual illustrations

[0073] Figure 1 This is a schematic diagram of the structure of the sodium bromide wastewater treatment device in the photoinitiator production process of Embodiment 1 of the present invention;

[0074] Figure 2 This is a schematic diagram of the structure of the sodium bromide wastewater treatment device in the photoinitiator production process of Embodiment 2 of the present invention;

[0075] Figure 3 This is a schematic diagram of the structure of the sodium bromide wastewater treatment device in the photoinitiator production process of Embodiment 3 of the present invention;

[0076] Figure 4 This is a schematic diagram of the structure of the sodium bromide wastewater treatment device in the photoinitiator production process of Embodiment 4 of the present invention;

[0077] 1-Distillation acidification kettle, 10-Sodium bromide wastewater inlet, 11-Adsorbent inlet, 12-Sulfuric acid inlet, 13-Mixed solution outlet, 14-Agitator, 15-Temperature control jacket, 16-Exhaust port, 17-Sight glass, 18-Sulfuric acid feed tank, 180-Sulfuric acid outlet, 181-Flow regulating valve, 19-Hydrogen peroxide feed tank, 190-Hydrogen peroxide outlet, 2-Filter, 20-Mixed solution inlet, 21-Clear liquid outlet, 22-Tank body, 23-Filter layer, 24-Discharge port, 3-Oxidation distillation Distillation vessel, 30-Clear liquid inlet, 31-Hydrogen peroxide inlet, 32-Steam outlet, 33-Distillation residue outlet, 4-Condenser, 40-Steam inlet, 41-Condensate outlet, 5-Divider, 50-Bromine outlet, 51-Condensate inlet, 52-Non-condensable gas exhaust outlet, 6-External condenser, 61-Storage tank, 7-Vacuum pump, 8-Bromine storage tank, 80-Bromine inlet, 9-Neutralization reactor, 90-Neutralization liquid inlet, 91-Liquid alkali inlet, 92-Neutralization liquid outlet. Detailed Implementation

[0078] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0079] Example 1

[0080] This embodiment provides a device for treating sodium bromide wastewater during the production of photoinitiators, such as... Figure 1 As shown, it includes a distillation acidification vessel 1, a filter 2, an oxidative distillation vessel 3, a condenser 4, and a separatory tank 5;

[0081] The distillation acidification vessel 1 is equipped with a sodium bromide wastewater inlet 10, an adsorbent inlet 11, and a sulfuric acid inlet 12. The bottom of the distillation acidification vessel 1 is equipped with a mixed liquid outlet 13.

[0082] The filter 2 is provided with a mixed liquid inlet 20, which is connected to the mixed liquid outlet 13; the bottom of the filter 2 is provided with a clear liquid outlet 21.

[0083] The oxidative distillation vessel 3 is provided with a clear liquid inlet 30, which is connected to the clear liquid outlet 21; the oxidative distillation vessel 3 is provided with a hydrogen peroxide inlet 31 and a steam outlet 32.

[0084] The condenser 4 is provided with a steam inlet 40, which is connected to the steam outlet 32; the condenser is provided with a condensate outlet 41, which is connected to the liquid separator 5.

[0085] The separating tank 5 is equipped with a bromine outlet 50;

[0086] The height of the distillation acidification vessel 1 is higher than the height of the filter 2;

[0087] The distillation acidification vessel 1 is equipped with a stirring paddle 14, and a temperature control sleeve 15 is provided outside the distillation acidification vessel 1; a steam coil and a cooling water coil are provided inside the temperature control sleeve 15.

[0088] The distillation acidification vessel 1 is provided with an exhaust port 16; the exhaust port 16 is connected to an external condenser 6, a liquid storage tank 61 and a vacuum pump 7.

[0089] The distillation acidification vessel 1 is equipped with a sight glass 17;

[0090] The filter 2 includes a tank 22 and a filter layer 23 horizontally arranged inside the tank. A discharge port 24 is provided on the tank 22 at a position corresponding to the filter layer 23.

[0091] The oxidative distillation vessel 3 is equipped with a stirring paddle 14, and a temperature control sleeve 15 is provided outside the oxidative distillation vessel 3; a steam coil and a cooling water coil are provided inside the temperature control sleeve 15.

[0092] The separatory tank 5 is provided with a condensate inlet 51 and a non-condensable gas outlet 52; the condensate inlet 51 is connected to the condensate outlet 41.

[0093] The processing device also includes a bromine storage tank 8, which is provided with a bromine inlet 80 and a bromine outlet 50 on the separatory tank 5 connected to the bromine storage tank 8.

[0094] This embodiment provides an operation method for the above-mentioned processing device, specifically including the following steps:

[0095] (1) Add sodium bromide wastewater and adsorbent to the distillation acidification kettle through the sodium bromide wastewater inlet and the adsorbent feed inlet, respectively. Turn on the agitator, vacuum pump and steam valve inside the temperature control jacket. The distillation temperature is generally 80℃~90℃. Perform reduced pressure distillation until sodium bromide is precipitated. Turn off the steam valve inside the temperature control jacket and vacuum pump to stop distillation and allow the pressure inside the kettle to return to normal pressure. When the temperature inside the kettle drops to ≤80℃, add sulfuric acid dropwise through the sulfuric acid inlet. During the dropwise addition process, control the temperature to ≤80℃ and observe the situation inside the kettle through the sight glass. If the foaming inside the kettle is violent or the temperature rises violently, the dropwise rate can be reduced. If it cannot be reduced, stop the dropwise addition until there is no foam and continue adding sulfuric acid. After the sulfuric acid dropwise addition is completed, continue stirring and mixing at 40℃~60℃ to obtain a mixed solution.

[0096] (2) The mixture from step (1) is discharged from the mixture outlet and enters the filter through the mixture inlet for filtration. The filtrate is discharged from the clear liquid outlet and added to the oxidative distillation kettle through the clear liquid inlet. The stirring paddle and the steam valve inside the temperature control jacket are turned on to raise the temperature. Hydrogen peroxide is added dropwise through the hydrogen peroxide inlet to carry out the reaction. The temperature is controlled at ≤80℃ during the dropwise addition process. The hydrogen peroxide dropwise addition time is generally 1h to 2h. The vapors of bromine and water are distilled out. After the hydrogen peroxide dropwise addition is completed, the temperature is raised to about 100℃ for heat preservation and stirring to continue distilling out the vapors of bromine and water. The above vapors are discharged from the steam outlet and enter the condenser through the steam inlet. After condensation, the condensate is obtained and discharged from the condensate outlet and enters the separator. After separation, the bromine is discharged from the bromine outlet and enters the bromine storage tank.

[0097] Example 2

[0098] The only difference between this embodiment and Embodiment 1 is that, Figure 2 As shown, the processing device also includes a sulfuric acid feeding tank 18, the height of which is higher than that of the distillation acidification kettle 1; a sulfuric acid outlet 180 is provided at the bottom of the sulfuric acid feeding tank 18, and the sulfuric acid outlet 180 is connected to the sulfuric acid filling port 12; a flow regulating valve 181 is provided at the sulfuric acid filling port 12.

[0099] The processing device also includes a hydrogen peroxide feeding tank 19, the height of which is higher than the height of the oxidative distillation kettle 3. The hydrogen peroxide feeding tank 19 is provided with a hydrogen peroxide outlet 190, which is connected to the hydrogen peroxide filling port 31. A flow regulating valve 181 is provided at the hydrogen peroxide filling port 31.

[0100] To facilitate control of the sulfuric acid and hydrogen peroxide dripping process, this embodiment includes a sulfuric acid feeding tank and a hydrogen peroxide feeding tank. During the operation of the treatment device, sulfuric acid is pre-poured into the sulfuric acid feeding tank, which is positioned higher than the distillation acidification vessel for easy control of the feeding. The dripping rate of sulfuric acid can be controlled by a flow regulating valve, thereby controlling the acidification process. Similarly, hydrogen peroxide is pre-poured into the hydrogen peroxide feeding tank, which is also positioned higher than the oxidation distillation vessel for easy control of the feeding. The dripping rate of hydrogen peroxide can be controlled by a flow regulating valve, thereby controlling the oxidation reaction.

[0101] Example 3

[0102] The only difference between this embodiment and Embodiment 2 is that, Figure 3 As shown, a sight glass 17 is provided at the condensate outlet 41 of the condenser 5.

[0103] In this embodiment, a sight glass is installed at the condensate outlet to observe the condensate flow rate, thereby controlling the hydrogen peroxide dripping rate. When the condensate flow rate is too high, the hydrogen peroxide dripping rate can be reduced; when the condensate flow rate is too low, the hydrogen peroxide dripping rate can be increased.

[0104] Example 4

[0105] The only difference between this embodiment and embodiment 3 is that, Figure 4 As shown, the processing device also includes a neutralization reactor 9, which is provided with a liquid inlet 90 for neutralizing the liquid to be added; the oxidative distillation reactor 3 is provided with a distillation residue outlet 33, which is connected to the liquid inlet 90 for neutralizing the liquid to be added; the neutralization reactor 9 is provided with a liquid alkali inlet 91 and a neutralization liquid outlet 92; a temperature control sleeve 15 is provided outside the neutralization reactor, and a stirring paddle 14 is provided inside the neutralization reactor.

[0106] After the reaction in the oxidative distillation vessel is completed, the liquid phase inside is acidic. This is transferred to a neutralization reactor, where liquid alkali is added for neutralization, yielding a sodium sulfate solution. This solution is then treated as wastewater, a process with relatively low difficulty. During operation, after the reaction in the oxidative distillation vessel is complete, the remaining distillate is discharged through the distillate outlet and enters the neutralization reactor. Liquid alkali is added through the liquid alkali inlet, and the agitator and temperature control jacket are activated to initiate the neutralization reaction. The temperature is controlled to not exceed 80°C throughout the process. After the reaction is complete, the neutralized liquid is discharged through the neutralized liquid outlet.

[0107] Application Example 1

[0108] This application example uses the treatment device in Example 4 to treat sodium bromide wastewater from the production process of photoinitiator 369. The specific operation method includes the following steps:

[0109] (1) Add 1t of 25% sulfuric acid to the sulfuric acid feeding tank, add 500kg of sodium bromide wastewater to the distillation acidification kettle, add 2.5kg of diatomaceous earth, turn on the agitator, vacuum pump and steam valve in the temperature control jacket, heat to 85℃ for reduced pressure distillation, when the amount of distilled out in the kettle reaches 250kg, observe the situation in the kettle, after sodium bromide can be clearly seen precipitating in the kettle, turn off the vacuum pump and steam valve in the temperature control jacket, stop distillation; restore the pressure in the kettle to atmospheric pressure, and cool down to 70℃; open the bottom valve of the sulfuric acid feeding tank, open the flow regulating valve, and slowly add 840kg of 25% sulfuric acid to the distillation acidification kettle, control the temperature at ≤80℃ during the dripping process, observe the sight glass during dripping, if foaming is violent or the temperature rises violently, the dripping rate can be reduced, if it cannot be reduced, stop feeding until there is no foam and continue feeding; after the sulfuric acid is added, control the temperature at 50℃ and continue stirring for 30min to obtain a mixed solution;

[0110] (2) Add 250 kg of 50% hydrogen peroxide to the hydrogen peroxide feeding tank; transport the mixture from step (1) to the filter for filtration, transport the filtrate to the oxidative distillation kettle, turn on the stirring paddle and the steam valve inside the temperature control jacket, raise the temperature to 60°C, turn on the flow regulating valve, add 200 kg of 50% hydrogen peroxide dropwise to the filtrate, control the temperature at 75°C during the dropwise addition process, carry out the reaction, and distill out the mixed vapor of bromine and water; after the hydrogen peroxide dropwise addition is completed, raise the temperature to 100°C and stir for 30 min, further distill out the vapor of bromine and water; transport the above vapor to the condenser, condense to obtain a mixture of bromine and water, and when no dark red liquid condenses out, the reaction is over; the above mixture enters the separator for separation, obtain the lower bromine and the upper aqueous phase, and transport the bromine to the bromine storage tank;

[0111] (3) Transfer the remaining liquid phase from the distillation vessel in step (2) through the distillation residue outlet and into the neutralization reaction vessel through the neutralization liquid inlet. Turn on the agitator and temperature control sleeve, and control the temperature below 60°C. Add liquid alkali into the vessel for neutralization. Control the temperature inside the vessel to not exceed 80°C during neutralization. Pay attention to the liquid level inside the vessel during neutralization to prevent overflow. Neutralize to pH 7.5 to obtain the neutralized liquid.

[0112] In this application example, the purity of the bromine obtained in step (2) is 94.1%, and the yield is 70%.

[0113] In this application example, the sodium bromide wastewater mentioned above is the sodium bromide wastewater obtained from the dimethylamine substitution reaction during the preparation of photoinitiator 369.

[0114] Application Example 2

[0115] The only difference between this application example and application example 1 is that the diatomaceous earth in step (1) of application example 1 is replaced with activated carbon powder, while the other parameters and conditions are exactly the same as in application example 1.

[0116] In this application example, the purity of the bromine obtained in step (2) is 93.7%, and the yield is 70%.

[0117] Application Example 3

[0118] The only difference between this application example and application example 1 is that the amount of diatomaceous earth added is replaced with 2 kg, while the other parameters and conditions are exactly the same as in application example 1.

[0119] In this application example, the purity of the bromine obtained in step (2) is 92%, and the yield is 67%.

[0120] Application Example 4

[0121] The only difference between this application example and application example 1 is that the amount of diatomaceous earth added is replaced with 3 kg, while the other parameters and conditions are exactly the same as in application example 1.

[0122] In this application example, the bromine obtained in step (2) has a purity of 94% and a yield of 70%.

[0123] Application Example 5

[0124] The only difference between this application example and application example 1 is that 840 kg of 25% sulfuric acid is replaced with 530 kg of 40% sulfuric acid; all other parameters and conditions are exactly the same as in application example 1.

[0125] In this application example, the bromine obtained in step (2) has a purity of 94% and a yield of 70%.

[0126] Application Example 6

[0127] The only difference between this application example and application example 1 is that the sulfuric acid is replaced with waste sulfuric acid produced by the bromination process of photoinitiator 369. The concentration of the waste sulfuric acid is 28%, and the amount added is 750 kg. All other parameters and conditions are exactly the same as in application example 1.

[0128] In this application example, the bromine obtained in step (2) has a purity of 94% and a yield of 75%.

[0129] The bromine prepared in the above application examples of the present invention meets the requirements of the raw material bromine in the production process of photoinitiator 369 and can be recycled.

[0130] Application Comparative Example 1

[0131] The only difference between this comparative example and Example 1 is that diatomaceous earth is not added in step (1), while the other parameters and conditions are exactly the same as in Example 1.

[0132] In this comparative example, the purity of the bromine obtained in step (2) is 90%, and the yield is 65%.

[0133] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A device for treating sodium bromide wastewater in a photoinitiator production process, characterized by, The distillation acidification kettle, the filter, the oxidation distillation kettle, the condenser and the liquid separation tank are arranged in sequence. The distillation acidification kettle is provided with a sodium bromide wastewater adding port, an adsorbent adding port and a sulfuric acid adding port. The filter is provided with a mixed liquid adding port. The oxidation distillation kettle is provided with a clear liquid adding port, a hydrogen peroxide adding port and a steam outlet. The condenser is provided with a steam inlet and a condensate outlet. The liquid separation tank is provided with a bromine outlet. The distillation acidification kettle is provided with an exhaust port connected to an external condenser, a liquid storage tank and a vacuum pump. The distillation acidification kettle and the filter are used for concentrating and acidifying sodium bromide wastewater and removing organic impurities. The distillation acidification kettle is provided with a sulfuric acid adding tank with a height higher than that of the distillation acidification kettle. The sulfuric acid adding tank is provided with a sulfuric acid outlet connected to the sulfuric acid adding port.

2. The processing device of claim 1, wherein, The sulfuric acid adding port is provided with a flow regulating valve. The distillation acidification kettle is provided with a temperature control sleeve. The distillation acidification kettle is provided with a sight glass.

3. The processing device of claim 1, wherein, The oxidation distillation kettle is provided with a temperature control sleeve. The distillation acidification kettle has a height higher than that of the filter. The filter comprises a tank body and a filter layer arranged horizontally in the tank body.

4. The processing device of claim 1, wherein, The filter is provided with a hydrogen peroxide adding tank with a height higher than that of the oxidation distillation kettle.

5. The processing device of claim 1, wherein, The hydrogen peroxide adding tank is provided with a hydrogen peroxide outlet connected to the hydrogen peroxide adding port.

6. The processing device of claim 1, wherein, The condenser is provided with a sight glass at the condensate outlet.

7. The processing device of claim 1, wherein, The liquid separation tank is provided with a condensate adding port and a non-condensable gas exhaust port.

8. The processing device of claim 1, wherein, The liquid separation tank is provided with a bromine storage tank connected to the bromine outlet.

9. The processing device of claim 1, wherein, The oxidation distillation kettle is provided with a distillation residual liquid outlet connected to a neutralization reactor.

10. The processing device of claim 9, wherein, The neutralization reactor is provided with a liquid caustic adding port and a neutralization liquid outlet. The neutralization reactor is provided with a temperature control sleeve and a stirring paddle.

11. A method for treating sodium bromide wastewater in a photoinitiator production process, characterized by, The treatment method adopts the sodium bromide wastewater treatment device in the production process of the photoinitiator according to any one of claims 1-10. The treatment method comprises the following steps: (1) adding the sodium bromide wastewater and the adsorbent into a distillation acidification kettle through a sodium bromide wastewater liquid inlet and an adsorbent liquid inlet respectively, and performing vacuum distillation until sodium bromide is precipitated, then adding sulfuric acid through a sulfuric acid liquid inlet, mixing to obtain a mixed liquid; (2) discharging the mixed liquid in step (1) through a mixed liquid liquid outlet and adding it into a filter through a mixed liquid liquid inlet to perform filtration, discharging the filtrate through a clear liquid liquid outlet and adding it into an oxidation distillation kettle through a clear liquid liquid inlet, adding hydrogen peroxide through a hydrogen peroxide liquid inlet to perform reaction, distilling bromine and water vapor, discharging the vapor through a vapor outlet and adding it into a condenser through a vapor inlet, obtaining a condensed liquid after condensation, discharging the condensed liquid through a condensed liquid liquid outlet and adding it into a liquid separator, and discharging bromine through a bromine liquid outlet after liquid separation.

12. The processing method according to claim 11, wherein, The sodium bromide wastewater is sodium bromide wastewater generated in the preparation process of an α-aminoacetophenone photoinitiator.

13. The processing method of claim 11, wherein, The adsorbent in step (1) is selected from any one or a combination of at least two of diatomite, activated carbon powder or resin.

14. The processing method of claim 11, wherein, The mass ratio of the sodium bromide wastewater to the adsorbent in step (1) is 150-250:

1.

15. The processing method of claim 11, wherein, The temperature of vacuum distillation in step (1) is 80-90°C.

16. The processing method of claim 11, wherein, The remaining solution after vacuum distillation in step (1) has a mass of 0.4-0.6 times the mass of the sodium bromide wastewater.

17. The processing method of claim 11, wherein, The sulfuric acid is added dropwise in step (1).

18. The processing method of claim 11, wherein, The temperature is controlled to ≤80°C during the addition of the sulfuric acid in step (1).

19. The processing method of claim 11, wherein, The mass ratio of the mass of H2SO4 to the mass of the sodium bromide wastewater in the addition of the sulfuric acid in step (1) is 0.35-0.55:

1.

20. The processing method according to claim 19, wherein, The mass ratio of the mass of H2SO4 to the mass of the sodium bromide wastewater in the addition of the sulfuric acid in step (1) is 0.4-0.45:

1.

21. The treatment method of claim 19, wherein, The concentration of the sulfuric acid in step (1) is 20%-40%.

22. The treatment method of claim 21, wherein, The concentration of the sulfuric acid in step (1) is 25%-30%.

23. The treatment method of claim 11, wherein, The temperature is controlled to 40-60°C during the mixing in step (1).

24. The treatment method of claim 11, wherein, The sulfuric acid in step (1) is selected from waste sulfuric acid generated in the production process of the α-aminoacetophenone photoinitiator.

25. The method of claim 11, wherein, The hydrogen peroxide is added dropwise in step (2).

26. The method of claim 11, wherein, The mass ratio of the mass of H2O2 to the mass of the sodium bromide wastewater in step (1) in the addition of the hydrogen peroxide in step (2) is 15%-30%.

27. The method of claim 11, wherein, The temperature is controlled to ≤80°C during the addition of the hydrogen peroxide in step (2).

28. The treatment method of claim 27, wherein, The temperature is controlled to 60-80°C during the addition of the hydrogen peroxide in step (2).

29. The treatment method of claim 28, wherein, The temperature is controlled to 75-80°C during the addition of the hydrogen peroxide in step (2).

30. The method of claim 11, wherein, After the addition of the hydrogen peroxide in step (2) is completed, the temperature is controlled to 95-105°C during distillation.

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