A method for continuously carbonating SEBS desalted wastewater and extracting and recovering neodecanoic acid

Abstract

The invention discloses a method for continuously carbonating SEBS desalination wastewater and extracting and recovering neodecanoic acid, wherein an empty tower is used as an extraction tower, pressurized carbon dioxide and a solvent used in the polymerization reaction of a lithium-based polymer are introduced to acidify and extract the SEBS desalination wastewater, and the obtained oil phase is returned to the SEBS glue solution for lithium removal; the obtained water phase is desalted water treatment unit. The invention uses an empty tower as an extraction tower, pressurized carbon dioxide and a solvent used in the polymerization reaction of a lithium-based polymer are introduced to acidify and extract, and has the advantages of high carbonic acid concentration, fast acidification reaction speed, high extraction rate, and stable operation control, so that the COD in the wastewater is reduced to less than 340 mg / L, and the recovery rate of neodecanoic acid is not less than 94%.

Description

Technical Field

[0001] The invention belongs to the technical field of petrochemical industry, and in particular relates to a method for continuously carbonating SEBS desalted wastewater and extracting and recovering neodecanoic acid. Background Art

[0002] SEBS is a hydrogenation product of styrene-butadiene elastomer (SBS). SEBS synthesized by the cyclopentadiene hydrogenation process uses alkyl lithium as the initiator of the polymerization reaction and the reducing agent of the hydrogenation catalyst. During the production process, the alkyl lithium is converted into lithium hydroxide and remains in the product. The residual lithium hydroxide not only decomposes and colors the antioxidant added during the production process, but also makes the lithium content in SEBS products high, making it difficult to meet the requirements of high-end fields such as food packaging and medical infusion equipment. Removing the residual lithium hydroxide in SEBS is the key to meeting the requirements of high-end fields.

[0003] The removal of residual metal catalyst lithium ions in existing SEBS usually includes inorganic acid washing, ammonium phosphate washing, citric acid washing, α-hydroxysulfonic acid solution washing, mixed acid washing, precipitation, passivation, extraction, electrostatic separation, etc. For example, (He Xiaojin et al. Removal of residual metal catalyst after polymer hydrogenation [P]. CN 92105370.3, 1992-07-08.) improved the oxidation-precipitation separation method, using polyalkyl glycol ether (such as polyethylene glycol ether) as a solubilizer to improve the complex precipitation ability of the dibasic acid, and the Ni and Al removal rate in the hydrogenated glue solution reached more than 99%. (Research on the removal of hydrogenation catalyst in styrene-butadiene-styrene block copolymer [J]. Elastomer, 2012, 22 (5)) discloses a method for removing residual catalyst in the glue solution after unsaturated polymer hydrogenation, using an oxidant and a dibasic acid to remove the hydrogenation catalyst and precipitant. Although this method has a high removal rate of residual catalyst in the polymer and can separate the dibasic acid solvent from the polymer solvent by distillation. However, the use of this method to separate the hydrogenation catalyst will result in high energy consumption, large fixed asset investment, complex filtration operation, low separation efficiency, easy clogging of the filter cloth, and certain limitations in the operation process. For example, USP3634549 (1972) and EP302505 (1989) introduce the mixing of an aqueous solution of sulfuric acid, hydrochloric acid, nitric acid and an oxidant (hydrogen peroxide) with a hydrogenated SEBS glue solution, and then separating the glue into two phases. However, this technology uses excessive strong acid, and the acidity in the medium seriously corrodes the steel equipment of industrial production, which is not suitable for industrial production.

[0004] In the preparation of SEBS lithium-containing rubber solution by SINOPEC Baling Petrochemical Company's Synthetic Rubber Plant, the method of lithium removal is to add organic acid to the active lithium polymer rubber solution, convert alkaline lithium into lithium organic acid (soap) and dissolve it in the aqueous phase, separate water and the rubber solution according to the density difference between the rubber solution and the aqueous phase, and lithium organic acid and other compounds enter the aqueous phase. At this time, the concentration of lithium organic acid in the wastewater is higher than 8×10 -3 mol / L, COD > 2400 mg / L, and pH value > 8. If this wastewater is directly discharged, the organic acid will be consumed. This environmentally unfriendly and uneconomical wastewater treatment method is not suitable for adoption. The invention patent of Liang Hongwen, Zhang Jianguo, Li Wangming, etc. of this company (CN201410181713.2, April 30, 2014. A cyclic method for recovering organic acid from lithium organic acid wastewater) found insoluble titanium dioxide-like precipitates after treating the aqueous phase obtained by acidifying the SEBS rubber solution with tert-decanoic acid in the SEBS rubber solution prepared by titanium-based catalysis with strong acids such as hydrochloric acid and sulfuric acid and carbon dioxide. The results show that the appearance and transparency of SEBS obtained by this technology are better than those without treatment. However, we know that in the industrial desalination process of SEBS, the temperature of the wastewater separated after acid neutralizing alkaline lithium is 75 - 85 °C. At this temperature, if strong acids such as hydrochloric acid and sulfuric acid are used as acidifying agents, the corrosion is strong and the requirements for equipment are high; while using carbon dioxide gas as an acidifying agent, its solubility is low, and the concentration of lithium neodecanoate in the wastewater is low, resulting in a very slow replacement rate, low efficiency of acidifying and reducing neodecanoic acid, and also consuming a large amount of carbon dioxide, with poor economy. Summary of the Invention

[0005] Aiming at the problems existing in the treatment of wastewater containing lithium organic acid generated by neutralizing alkali lithium ions in the existing SEBS rubber solution with neodecanoic acid, the purpose of the present invention is to provide a method for continuously carbonic acid acidifying SEBS desalination wastewater and extracting and recovering neodecanoic acid. Using an empty tower as an extraction tower, introducing pressurized carbon dioxide and the solvent used in the polymerization reaction of lithium-based polymers for acidification and extraction, which has the advantages of high carbonic acid concentration, fast acidification reaction rate, high extraction rate, and stable operation control, reducing the COD in the wastewater to less than 340 mg / L, and the recovery rate of neodecanoic acid not less than 94%.

[0006] To achieve the above technical objectives, the present invention adopts the following technical solutions:

[0007] A method for continuously carbonic acid acidifying SEBS desalination wastewater and extracting and recovering neodecanoic acid, using an empty tower as an extraction tower, introducing pressurized carbon dioxide and the solvent used in the polymerization reaction of lithium-based polymers to acidify and extract the SEBS desalination wastewater, and returning the obtained oil phase to the SEBS rubber solution for the neodecanoic acid lithium removal unit, and sending the aqueous phase to the sewage treatment unit.

[0008] Preferably, the SEBS desalination wastewater is derived from the neutralization reaction of the SEBS hydrogenated gel with neodecanoic acid, cyclohexane and water, and the aqueous phase produced by the stratification has a temperature of 75-85°C and a concentration of lithium neodecanoate>8×10 -3 mol / L, COD>2400mg / L, PH value>8.

[0009] Preferably, the volume ratio of SEBS desalination wastewater to solvent is 3.0-4.5:1.

[0010] Preferably, the pressure of the pressurized carbon dioxide is 0.1-0.6 MPa, more preferably 0.25-0.35 MPa; the temperature of the acidification reaction is 35-50°C.

[0011] The reaction of carbon dioxide with lithium neodecanoate in SEBS desalted water is a double decomposition reaction. As we all know, the acidity of carbonic acid is stronger than that of neodecanoic acid, and it is not difficult to replace neodecanoic acid with lithium neodecanoate. Although carbon dioxide dissolves in water to form carbonic acid, the solubility of carbon dioxide increases with the increase of air pressure and the decrease of water temperature. The solubility of carbon dioxide in water at normal pressure (g / 100g water) is 0.33g, 0.15g, 0.09g and 0.06g at 0℃, 25℃, 45℃ and 60℃ respectively; at 10℃, the solubility is 40.4% (mass), 52.3% (mass) and 70.1% (mass) at 0.1Mpa, 0.2Mpa and 0.4Mpa respectively; at 30℃, the solubility is 1.23dm 3 / kg, 2.50dm 3 / kg, and 3.70dm 3 / kg; the solubility at 40℃, 50℃ and 60℃ under 2.5Mpa is 11.62, 9.71 and 8.51 (dm 3 / kg).

[0012] At the same time, in the industrial SEBS desalination process, the temperature of the separated wastewater after acid neutralization of alkaline lithium is 75-85°C. Low temperature is beneficial to the dissolution of carbon dioxide in water and increases its reaction concentration and reaction rate. However, it is obvious that too low acidification temperature requires forced cooling of water, which will increase cooling equipment, energy consumption and heat transfer area; while too high acidification temperature will reduce the solubility of carbon dioxide in desalted water and reduce the rate of replacement reaction.

[0013] That is, the solubility of carbon dioxide in water is extremely low at normal pressure and high temperature, and the concentration of lithium neodecanoate in SEBS desalted water is low, resulting in a very slow replacement speed, low efficiency of acidification reduction of lithium neodecanoate, and a large amount of carbon dioxide is consumed, resulting in poor economic efficiency. Therefore, the present invention uses pressurized carbon dioxide while appropriately reducing the temperature of SEBS desalted wastewater, which has the advantages of high carbonic acid concentration and fast acidification reaction speed.

[0014] Preferably, the solvent is cyclohexane or cyclohexane containing neodecanoic acid, wherein the mass content of neodecanoic acid in cyclohexane is ≤5wt%.

[0015] Preferably, the extraction tower body adopts a jacket design, and the jacket is located between the extraction tower solvent inlet and the SEBS desalination wastewater inlet (this section is marked as "acidification extraction section"). In the present invention, circulating water at 20-25°C is passed into the jacket to control the temperature of the acidification reaction, and the acidification reaction temperature is controlled to be 35-50°C.

[0016] Preferably, the material of the extraction tower is carbon steel or 1Cr18Ni9Ti, and more preferably 1Cr18Ni9Ti.

[0017] Preferably, the extraction tower is divided into a tower head and a tower body, and the extraction tower is divided into a light oil phase neodecanoic acid-cyclohexane solution settling section, an acidification-extraction section and a heavy water phase settling section from top to bottom, wherein the light oil phase neodecanoic acid-cyclohexane solution settling section is from the SEBS desalination wastewater inlet to the top of the tower head, the acidification-extraction section is from the SEBS desalination wastewater inlet to the solvent inlet, and the heavy water phase settling section is from the solvent inlet to the bottom of the tower body.

[0018] In the present invention, the neodecanoic acid-cyclohexane solution captured by acidification-extraction is continuously separated from the neodecanoic acid-cyclohexane solution overflow port on the side of the tower head into the cyclohexane storage tank, and then circulated into the extraction tower as an extraction solvent until the mass fraction of neodecanoic acid in the cyclohexane storage tank is greater than 5wt%, and then it is sent to the SEBS glue desalting unit for neutralization and desalination, and new cyclohexane is replaced as the extraction solvent.

[0019] Preferably, the height (H) to diameter (d) ratio of the tower body is H / d=(5-20) / 1, more preferably H / d=(8-15) / 1.

[0020] Preferably, the height (h) to diameter (D) ratio of the tower head is h / D=(1.0-1.5) / 1.

[0021] Preferably, the ratio of the tower head diameter to the tower body diameter D / d=(1.0-1.5) / 1.

[0022] Preferably, the ratio of the tower body height (H) to the heavy water phase settling section height (A) is H / A=(10-15) / 1.

[0023] The inventors found that due to various reasons such as equipment failure during the centrifuge dehydration process, some SEBS glue in the SEBS desalination wastewater will enter the desalted water in a disorderly manner, causing the glue to block the coils or fillers in the tower, resulting in a "dull tower" phenomenon, which ultimately makes the extraction tower unusable or scrapped. Therefore, in the present invention, one of the cores of acidification-extraction is to set the interior of the extraction tower as an empty tower, and it is not appropriate to use an internal cooling coil as a heat exchanger to cool the desalted water, nor is it appropriate to install inorganic or polymer fillers such as Raschig rings in the tower to increase the mass transfer and heat transfer efficiency between the reaction materials by bubbling carbon dioxide gas and water.

[0024] Preferably, the acidification-extraction section is provided with a longitudinal paddle agitator, and a plurality of groups of blades are evenly distributed on the agitator shaft, the blades are arranged at a spacing of (1-2 groups) / meter, and the ratio of blade length to tower radius is 0.7-0.8.

[0025] Preferably, the stirring speed of the paddle stirrer is 60 to 1400 r / min, more preferably 80 to 240 r / min.

[0026] Neodecanoic acid has a density of 0.911 and is insoluble in water. Although the acidification of neodecanoic acid lithium in carbonic acid and SEBS desalination wastewater belongs to the reaction of homogeneous dilute solution, the cyclohexane extraction is carried out under a heterogeneous state, and the neodecanoic acid microparticles displaced will only be captured and dissolved mutually to form larger oil particles to float when they collide with cyclohexane. Therefore, in the present invention, a longitudinal paddle stirrer is set in the acidification-extraction section so that the acidification-extraction is carried out under agitation, which is beneficial to mass transfer and heat transfer, and improves the neodecanoic acid extraction rate. Although too high agitation speed is useful for acidification-extraction, for an extraction tower with a relatively large length (height) diameter, too high agitation speed is industrially difficult to achieve.

[0027] The present invention unexpectedly discovered that a tower acidification extraction equipment using pressurized carbon dioxide, jacket cooling and further adding a longitudinally arranged paddle agitator has the advantages of high carbonic acid concentration, fast acidification reaction speed, high extraction rate and stable operation control.

[0028] In the present invention, an empty tower is used as an acidification-extraction device, and pressurized carbon dioxide is used as an acidifier. The device is simple, the production operation is convenient, and the carbon dioxide consumption is low. While the loss of the device is low or almost no loss, the COD in the SEBS desalination wastewater can be reduced from a state of more than 2400 mg / L to less than 340 mg / L, and the pH value of the effluent is 6-6.5. The industrial technology of continuously acidifying the lithium neodecanoate in the SEBS desalination wastewater with pressurized carbon dioxide, and extracting and displacing the neodecanoic acid with cyclohexane or cyclohexane containing neodecanoic acid and recycling it to the SEBS desalination unit, the recovery rate of the neodecanoic acid is not less than 94%, the neodecanoic acid is effectively recovered and reused, the quality of the SEBS product is improved, the economic benefit is increased, and the treatment load and treatment cost of the discharged water are reduced. At the same time, it avoids the problems of corrosion to equipment caused by the method of using strong acid to acidify lithium neodecanoate in desalination wastewater, or the method of using atmospheric pressure carbon dioxide gas to acidify lithium neodecanoate in desalination wastewater, which are well known to technical personnel in the industry, such as slow replacement speed, low efficiency of acidification reduction of neodecanoic acid, large carbon dioxide consumption, and poor economy. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 The present invention is a process flow diagram of a method for continuously carbonating SEBS desalted wastewater and extracting and recovering neodecanoic acid. DETAILED DESCRIPTION

[0030] In the following examples, the pH value of the wastewater was determined by the electrode method in accordance with GB6920-86; the COD was determined by the potassium dichromate method in accordance with GB11914-89; the cyclohexane and neodecanoic acid content was analyzed by gas chromatography in accordance with ASTM D7871-2013; and the lithium content was determined by atomic absorption analyzer.

[0031] like Figure 1As shown, first, the SEBS desalination wastewater in the water tank is pumped into the N7 inlet (SEBS desalination wastewater inlet) of the extraction tower by a metering pump. After the extraction tower is filled with wastewater to 1 / 3 of the tower height, cooling water is introduced into the jacket to remove the heat of the SEBS desalination wastewater. A constant amount of carbon dioxide gas is filled into N4 or N5 (pressurized carbon dioxide inlet) at the bottom of the tower. At the same time, cyclohexane solvent is added into N8 or N9 (solvent inlet) by a metering pump. When the liquid in the tower reaches N-2 (overflow port of neodecanoic acid-cyclohexane solution), At the same time, the opening of the N-2 overflow valve is controlled, and the original air in the tower is discharged at N1 (exhaust port) to keep the operating pressure of carbon dioxide in the tower constant. At the same time, the opening of the outlet valve at N6 at the bottom of the tower (heavy water phase outlet) is adjusted. The continuous operating conditions are: the feed amount of the solvent is balanced with the overflow circulation recovery amount; the incoming amount of SEBS desalination wastewater is balanced with the discharge amount of heavy water phase. The water phase (pH6~6.5, COD value <340mg / L) coming out of the bottom of the tower after acidification, extraction and sedimentation enters the sewage treatment system.

[0032] Example 1

[0033] The extraction tower has a height (H) of 15m and a diameter (d) of 1.2m. The tower head has a height (h) of 2.0m and a diameter (D) of 1.8m. The height of the heavy water phase settling section (A) is 1.25m, and the height of the acidification-extraction section (HA) is 13.75m. The jacket outside the tower is located in the acidification-extraction section, and its height is 13.75m. A stirring motor and a reducer combination are installed on the top of the tower. The stirring inside the tower is a 3-blade stirring 13 groups (sections) of 1 section / meter, and is evenly installed on the stirring shaft. The blade length is 0.48m, and is evenly distributed in the acidification-extraction section. The extraction tower is made of 1Cr18Ni9Ti, the jacket is made of 16Mn steel, the design pressure is 0.8Mpa, and the tower volume is 17m 3 .

[0034] SEBS desalination wastewater: the concentration of lithium neodecanoate is 8.6×10 -3 mol / L, COD is 2420mg / L, pH value is 12, and temperature is 70℃.

[0035] First, SEBS desalination wastewater was pumped at 5.5 m 3 / h flow rate into the N7 inlet of the extraction tower, and start stirring and pass 15-20℃ circulating cooling water into the jacket. After the material in the tower is filled to 1 / 3 of the tower height, pressurized carbon dioxide is filled into N5, and the top vent valve of the tower is adjusted to N1 to exhaust the air in the tower; at the same time, a metering pump is used at N9 with a flow rate of 1.8m 3 / h of solvent was added. When the liquid in the tower reached N-2, the opening of the N-2 overflow valve was controlled, and the pressure in the extraction tower was controlled to balance the solvent feed amount with the overflow circulation recovery amount at the top of the tower, and the SEBS desalination wastewater intake with the water output at the bottom of the tower. The results are shown in Table 1.

[0036] Table 1 Continuous test results under different process conditions

[0037] Continuous acidification time (period) / day 1 10 20 30 50 70 90 Tower top pressure(Mpa) 0.28 0.28 0.30 0.20 0.33 0.35 0.35 Acidification temperature (℃) 45 50 40 33 45 35 40 Stirring speed (rpm) 80 100 120 140 160 200 240 Wastewater / Solvent(V) 3.0 3.5 4.0 3.3 4.5 4.0 4.5 <![CDATA[Inlet flow rate (m 3 / h)]]> 5.50 6.3 7.2 5.9 8.1 7.2 8.1 <![CDATA[Water flow rate (m 3 / h)]]> 5.49 6.29 7.18 5.88 8.08 7.18 8.07 Wastewater retention time (min) 165 145 126 155 112 126 112 Outlet pH 6.5 6.4 6.5 6.2 6.3 6.5 6.6 Neodecanoic acid content in oil phase (wt%) 0.12 0.17 0.19 0.21 0.15 0.18 0.19 Neodecanoic acid recovery rate / % 94.8 95.6 96.5 97.3 94.1 96.6 95.7 Outlet COD (mg / L) 304 336 327 318 338 316 326

[0038] Note: Residence time = (empty tower volume - solvent volume flow rate) / SEBS desalination wastewater flow rate.

[0039] Under the continuous operation of acid extraction, the pressure is 0.20-0.35Mpa, the temperature is 35-50℃, the SEBS desalination wastewater / solvent (volume ratio) is 3.0-4.5, and the residence time is 110-160min. The results are surprising, that is, the recovery rate of neodecanoic acid extraction is not less than 94%, the effluent COD is <340mg / L, and the continuous operation is 90 days without any failure.

[0040] Example 2

[0041] On the basis of Example 1, the constant wastewater / solvent (volume ratio) was 3.5, the acidification temperature was 45°C, the tower pressure was 0.30 MPa, and the wastewater residence time was 145 min. Only some parameters of the acidification extraction tower were changed. The results are shown in Table 2.

[0042] Table 2 Process operation results of different extraction tower parameters

[0043] project 2-1# 2-3# 2-3# 2-4# 2-5# 2-6# 2-7# 2-8# H / d 15 15 15 7 5 10 17 8 H / A 15 10 10 12 12 8 17 10 Stirring speed (rpm) 120 140 160 120 120 120 120 120 Stirring density (group / m) 1 0.5 0.25 1 1 1 2 2 pH value of effluent 6.2 6.6 7.4 7.2 7.8 7.1 6.9 6.4 Neodecanoic acid recovery rate / % 96.8 91.4 83.3 87.6 82.6 88.4 92.5 96.3 Outlet COD (mg / L) 312 486 725 698 737 650 463 336

[0044] Note: "H / d" is the ratio of the length to the height of the tower body, "H / A" is the ratio of the tower body height to the height of the heavy water phase settling section, and "stirring density" is the number of stirring blade groups (sections) evenly installed per unit meter height on the stirring shaft.

[0045] It can be seen from Table 2 that when the height-to-diameter ratio of the extraction tower H / d=(8-15) / 1, the ratio of the tower height to the height of the heavy water phase settling section H / A=10-15 / 1, the stirring density is 1-2 groups / m and the stirring speed is relatively low, better acidification effect and extraction efficiency can be obtained, and the effluent COD value is also relatively low.

[0046] Comparative Example 2

[0047] The design parameters and process conditions of the relevant extraction tower in Example 2-1# were kept unchanged, except that stirring was not provided. As a result, the recovery rate of neodecanoic acid was 79.4%, and the effluent COD was 866 mg / L.

[0048] Comparative Example 3

[0049] In the constant example 2-8#, the design parameters and process conditions of the relevant extraction tower remain unchanged, and only ceramic Raschig rings are filled in the tower body. As a result, the recovery rate of neodecanoic acid is 68.5%, and the effluent COD is 943 mg / L. After 12 days of continuous operation, the extraction tower is blocked by SEBE glue liquid, resulting in a "dull tower" that cannot be operated.

[0050] Comparative Example 4

[0051] The relevant process conditions in Example 1 remain unchanged, and only the acidification temperature, carbon dioxide pressure and wastewater / solvent (volume) ratio and other related conditions are adjusted. The results are shown in Table 3.

[0052] Table 3 Process operation results under different process conditions

[0053] project 5-1# 5-2# 5-3# 5-4# 5-5# Tower top pressure(Mpa) Normal pressure bubbling 0.22 0.25 0.30 0.35 Acidification temperature (℃) 25-30 35-40 35-40 60-65 70-75 Stirring speed (rpm) 120 0 0 200 240 Wastewater / Solvent(V) 3.0 3.0 6.0 4.0 3.5 <![CDATA[Inlet flow rate (m 3 / h)]]> 5.50 5.50 10.8 7.2 6.3 <![CDATA[Water flow rate (m 3 / h)]]> 5.49 5.49 10.78 7.17 6.28 Wastewater retention time (min) 165 165 84 126 145 pH value of effluent 6.5 6.5 6.6 6.6 6.4 Neodecanoic acid content in oil phase (wt%) 0.05 0.09 0.06 0.07 0.04 Neodecanoic acid recovery rate / % 83.7 78.7 75.6 84.5 81.6 COD(mg / L) 753 846 904 712 783

[0054] As can be seen from Table 3, too low carbon dioxide operating pressure, too high feed ratio, too high acidification temperature and too low material residence time are not conducive to the complete acidification reaction and extraction.

Claims

1. A method for continuously carbonating SEBS desalted wastewater and extracting and recovering neodecanoic acid, characterized in that: An empty tower is used as an extraction tower, and pressurized carbon dioxide and a solvent used for the polymerization reaction of a lithium-based polymer are introduced to acidify and extract SEBS desalination wastewater, and the obtained oil phase is returned to the SEBS glue solution for use in a neodecanoic acid lithium removal unit and a water phase desalination wastewater treatment unit; the pressure of the pressurized carbon dioxide is 0.20-0.35 MPa, and the temperature of the acidification reaction is 35-50° C. The extraction tower is divided into a tower head and a tower body, and the extraction tower is sequentially divided from top to bottom into a light oil phase neodecanoic acid-cyclohexane solution precipitation section, an acidification-extraction section, and a heavy water phase precipitation section, wherein the section from the SEBS desalination wastewater inlet to the top of the tower head is the light oil phase neodecanoic acid-cyclohexane solution precipitation section, the section from the SEBS desalination wastewater inlet to the solvent inlet is the acidification-extraction section, and the section from the solvent inlet to the bottom of the tower body is the heavy water phase precipitation section; The height-to-diameter ratio of the tower body is H / d=(8-15) / 1; The height-to-diameter ratio of the tower head h / D=(1.0-1.5) / 1; The ratio of the tower head diameter to the tower body diameter is D / d=(1.0-1.5) / 1; The ratio of the tower body height to the heavy water phase settling section height H / A = (10-15) / 1; The acidification-extraction section is provided with a longitudinal paddle stirrer, and a plurality of groups of blades are evenly distributed on the stirring shaft, the arrangement spacing of the blades is (1-2 groups) / meter, and the ratio of the blade length to the tower body radius is 0.7-0.8; The stirring speed of the paddle stirrer is 60 to 1400 r / min; The SEBS desalination wastewater is derived from the neutralization reaction of the SEBS hydrogenated gel with neodecanoic acid, cyclohexane and water, and the aqueous phase produced by the stratification has a temperature of 75-85°C and a concentration of lithium neodecanoate>8×10 -3 mol / L, COD>2400mg / L, pH value>8.

2. The method for continuously carbonating SEBS desalted wastewater and extracting and recovering neodecanoic acid according to claim 1, characterized in that: The volume ratio of SEBS desalination wastewater to solvent is 3.0-4.5:

1.

3. The method for continuous carbonation of SEBS desalted wastewater and extraction and recovery of neodecanoic acid according to claim 1, characterized in that: The solvent is cyclohexane or cyclohexane containing neodecanoic acid, wherein the mass content of neodecanoic acid in cyclohexane is less than or equal to 5wt%.

4. The method of continuously carbonating SEBS desalted wastewater and extracting and recovering neodecanoic acid according to claim 1, characterized in that: The extraction tower body adopts a jacketed design, and the jacket is located between the extraction tower solvent inlet and the SEBS desalination wastewater inlet.

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