Phenol acetone production and wastewater treatment system and process

Abstract

The application provides a phenol acetone production and wastewater treatment system and process, and belongs to the technical field of chemical industry and environmental protection. The production system comprises a decarbonator added between acid catalysis and alkali neutralization in a phenol acetone production process to remove alkalinity. The wastewater treatment process comprises an organic metal ultrafiltration membrane, evaporation concentration, frozen crystallization, organic matter removal, evaporation crystallization and mother liquor drying. The treatment system and process can realize zero discharge of phenol acetone production wastewater, and have the advantages of short treatment process, low energy consumption and high product salt quality.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of chemical industry and environmental protection, and particularly relates to a phenol acetone production and wastewater treatment system and process. BACKGROUND

[0002] High-concentration high-salt wastewater treatment is a recognized problem in the petroleum refining industry, including phenol acetone wastewater. The wastewater discharged by phenol acetone production has high organic matter concentration and complex composition, and contains high-concentration salts, which is a relatively difficult chemical wastewater to treat. The high sulfate content and high organic matter concentration of phenol acetone production wastewater have a great toxic effect on microorganisms in conventional biological treatment methods.

[0003] Currently, the treatment technologies for phenol acetone wastewater mainly include adsorption method, biological treatment method, wet peroxide oxidation treatment technology, and electro-catalytic oxidation technology, but there are still problems such as high COD, high color, difficult deep treatment, and non-resource utilization, which have become one of the important factors restricting the wastewater treatment of petrochemical enterprises to meet the standards. With increasingly stringent environmental protection standards, traditional treatment technologies have been difficult to meet higher requirements. Since the wastewater discharged by phenol acetone production contains high-concentration sulfate, if it is treated for zero discharge, it can be converted into valuable industrial salt.

[0004] In the process of near-zero discharge treatment of high-salt industrial wastewater, the core mainly includes pretreatment, reduction, and evaporation crystallization. Currently, the zero discharge treatment of high-salt industrial wastewater usually first removes hardness and decarbonizes to remove colloidal substances, hardness, and alkalinity in industrial wastewater, and then performs traditional thermal crystallization to reduce the pollution of pollutants to the subsequent reduction unit, or to reduce the corrosion and scaling and plugging of the equipment in the subsequent thermal concentration unit. However, there are problems such as long process, large occupied area, and high energy consumption, and the decarbonization unit will add acid, increasing industrial salt.

[0005] Based on the existing phenol acetone production process, the production process is regulated, and a zero discharge process for phenol acetone production wastewater is developed, which can realize the quality improvement of product salt and truly realize the resource treatment of phenol acetone production wastewater, which has great significance. SUMMARY

[0006] In view of the defects in the prior art, the purpose of the present application is to provide a phenol acetone wastewater production and wastewater treatment system and process, which solves the problems of difficult treatment, high energy consumption, and poor treatment effect of chemical enterprises.

[0007] Currently, the preparation of phenol and acetone by isopropylbenzene method is the main production route in the world (such as Figure 2The phenol-acetone production system mainly includes a hydrocarbon process, an oxidation process, a decomposition-refining process and a recovery process. In the oxidation process, cumene is oxidized into cumene hydroperoxide; in the decomposition-refining process, phenol and acetone are obtained mainly by using sulfuric acid as a catalyst, and then NaHCO3 is added into a neutralization kettle to remove sulfuric acid and prevent phenol from being converted into phenolate. In order to shorten the subsequent phenol-acetone production wastewater treatment process and reduce the generation of impurities, a decarbonator is added between the acid catalysis and the alkali neutralization in the decomposition-refining process. The decarbonator can remove HCO3 - , CO3 2- under the acidic conditions when the cumene hydroperoxide is decomposed into phenol and acetone.

[0008] According to one aspect of the present application, a phenol-acetone production and wastewater treatment system is provided, which comprises a production system and a wastewater treatment system; the production system comprises a reactor, an evaporator, a decomposition kettle, a neutralization kettle, a water washing tower and a distillation tower which are sequentially connected by pipelines; a decarbonator is arranged between the decomposition kettle and the neutralization kettle; the wastewater generated by the production system enters the wastewater treatment system through a pipeline;

[0009] The wastewater treatment system comprises an organometallic membrane filter, an evaporation concentrator, a refrigeration water inlet adjusting tank, a refrigeration crystallization device, an electro-catalytic oxidation device and an evaporation crystallizer which are sequentially connected by pipelines.

[0010] The refrigeration crystallization device comprises a mother liquor outlet I, and the mother liquor outlet I is connected with a mother liquor drying unit.

[0011] The evaporation crystallizer comprises a mother liquor outlet II, and the mother liquor outlet II is in communication with the refrigeration water inlet adjusting tank.

[0012] Optionally, the pore size of the membrane material in the organometallic membrane filter is 5-50 nm, and the flux is 20-150 LMH.

[0013] Optionally, the decarbonator is selected from a blast decarbonator; the gas-water ratio in the decarbonator is 20-35 m 3 air / m 3 water.

[0014] Optionally, the evaporation concentrator is selected from a multi-effect evaporation concentrator or an MVR evaporation concentrator.

[0015] Optionally, the refrigeration crystallization device is selected from an FC type crystallizer, a DTB type crystallizer or an Oslo crystallizer.

[0016] Optionally, the electro-catalytic oxidation device is provided with an anode plate and a cathode plate, and the distance between the anode plate and the cathode plate is 2-6 cm.

[0017] Optionally, the material of the anode plate is selected from any one of noble metal, metal oxide, metal matrix composite or diamond, and the material of the cathode is selected from any one of carbon, carbon matrix composite, noble metal, metal oxide or stainless steel.

[0018] Optionally, the content of bicarbonate in the wastewater produced by the production system is not more than 50 mg / L.

[0019] According to another aspect of the present application, a phenol and acetone production and wastewater treatment process using the above system is provided, which comprises the following steps: oxidizing and decomposing cumene, carrying out decarbonization treatment, and then recovering and treating to obtain phenol and acetone; and treating the phenol and acetone wastewater produced in the production process.

[0020] The wastewater treatment process comprises the following steps:

[0021] (1) filtering to remove petroleum substances and suspended solids in the phenol and acetone wastewater;

[0022] (2) carrying out evaporation concentration and then freezing crystallization;

[0023] (3) removing organic substances and carrying out evaporation crystallization to obtain sodium sulfate crystals.

[0024] Optionally, the decarbonization treatment time is 15-25 minutes.

[0025] Optionally, in step (2), the salt content of the evaporation concentrated effluent is ≥200,000 mg / L.

[0026] Optionally, in step (2), the freezing crystallization temperature is -3-0℃.

[0027] Optionally, the freezing crystallization temperature is -2.5℃, -2℃, -1.5℃, -1℃, -0.5℃, or any value between any two of the above values.

[0028] Optionally, in step (3), the organic substance removal is carried out by electro-catalytic oxidation treatment, and the current density of the electro-catalytic oxidation treatment is 80-300 mA / cm 2 , and the reaction time is 3-120 minutes.

[0029] Optionally, in step (3), the evaporation crystallization conditions include: pressure 0.4-1 MPa, feed temperature 40-60℃, and evaporation temperature 50-70℃.

[0030] Optionally, the phenol acetone wastewater has the following water quality characteristics: acetone 50-300 mg / L, petroleum substances 1-300 mg / L, COD 3000-6000 mg / L, TDS 30000-40000 mg / L, total alkali 40-50 mg / L, and temperature 70-90℃.

[0031] The present application adopts a pre-decarbonization process, and then processes the phenol acetone wastewater through "organic metal membrane filtration + three-effect evaporation + refrigeration crystallization + organic matter removal + evaporation crystallization". By using the treatment process, zero discharge and resource utilization of the phenol acetone wastewater are realized. Compared with the prior art, the process of the present application has good effluent water quality, reduces the use amount of acid and alkali, reduces the generation of miscellaneous salt, and has a short treatment process and low energy consumption. Specific beneficial effects include:

[0032] (1) The organic metal ultrafiltration membrane is used to effectively remove machine impurities and petroleum substances in the presence of acetone;

[0033] (2) The refrigeration crystallization process is adopted. In the NaCl-Na2SO4-H2O three-phase system, when the temperature is less than 40℃, the solubility of Na2SO4 increases with the increase of temperature. At 80℃ (the discharge temperature of three-effect evaporation), the solubility of sodium sulfate is 43.7g / 100g (at this time, the calcium ion is 500mg / L, and the scaling occurs). At 0℃, the solubility of sodium sulfate is 4.9g / 100g. At-5-0℃, the solubility of sodium sulfate is 0%-5%. The refrigeration desulfurization utilizes this principle to crystallize Na2SO4·10H2O at low temperature, so that a relatively pure product salt is obtained. The hardening unit can be omitted, the occupation area is small, no salt is added, and the solid hazardous waste production is reduced;

[0034] (3) The phenol acetone production process is optimized. The decarburization is performed before the alkali neutralization, so as to reduce the generation of miscellaneous salt in the subsequent process;

[0035] (4) The phenol acetone production wastewater directly enters the evaporation concentration unit after the organic metal membrane filtration unit, so that the temperature reduction is less, the preheating energy consumption is reduced, and the energy is effectively saved and decarburized;

[0036] (5) The electro-catalytic oxidation decolorization is adopted to ensure the quality of the product salt. BRIEF DESCRIPTION OF DRAWINGS

[0037] Figure 1 The figure is a phenol acetone wastewater treatment process flow chart of the present application.

[0038] Figure 2 The figure is a phenol acetone production process flow chart of the prior art.

[0039] Figure 3 The figure is a phenol acetone wastewater treatment system schematic diagram of the present application. DETAILED DESCRIPTION

[0040] The present invention will be further described below with reference to specific embodiments, but this does not constitute any limitation on the present invention.

[0041] A phenol-acetone production and wastewater treatment system is disclosed. The production system includes a reactor, an evaporator, a decomposition vessel, a neutralization vessel, a water washing tower, and a distillation tower connected sequentially by pipelines. A decarbonization unit is installed between the decomposition vessel and the neutralization vessel. The decarbonization unit is a blower-type decarbonization unit, in which air blown into the decarbonization unit comes into contact with the liquid being sprayed in. The air-to-water ratio inside the decarbonization unit is 20-35 m³ / h. 3 air / m 3 Water; wastewater generated by the production system enters the wastewater treatment system through pipelines.

[0042] like Figure 3 As shown, the wastewater treatment system includes an organometallic membrane filter, an evaporator / concentrator, a chilled water inlet regulating tank, a cryogenic crystallizer, an organic matter removal device, and an evaporator / crystallizer connected sequentially via pipelines. The cryogenic crystallizer includes a mother liquor outlet I, which is connected to a mother liquor drying unit. The evaporator / crystallizer includes a mother liquor outlet II, which is connected to the inlet of the chilled water inlet regulating tank. A centrifuge and a dissolving tank are sequentially arranged between the cryogenic crystallizer and the electrocatalytic oxidation device. The organic matter removal device can be an electrocatalytic oxidation device. The product water outlet of the organometallic membrane filter is connected to the inlet water of the evaporator / concentrator. The product water outlet of the evaporator / concentrator is connected to the inlet water of the cryogenic crystallizer via the chilled water inlet regulating tank. The product water outlet of the cryogenic crystallizer is connected to the dissolving tank via the centrifuge. The high-concentration sodium sulfate solution outlet of the dissolving tank is connected to the inlet water of the electrocatalytic oxidation device. The product water outlet of the electrocatalytic oxidation device is connected to the inlet water of the evaporator / crystallizer.

[0043] The organometallic membrane filter uses an organometallic ultrafiltration membrane to remove petroleum-based substances and suspended solids from wastewater. The evaporator concentrates and reduces the volume of wastewater, which then enters the cryogenic crystallization unit via a chilled water inlet regulating tank. The cryogenic crystallization unit obtains crude sodium sulfate crystals and dissolves them into a high-concentration sodium sulfate solution. The mother liquor produced by the cryogenic crystallization unit enters the mother liquor drying unit for drying. The organic matter removal unit removes organic matter and color from the high-concentration sodium sulfate solution. The resulting sodium sulfate solution is then processed by an evaporator crystallizer to produce anhydrous sodium sulfate. The mother liquor produced by the evaporator crystallizer is returned to the chilled water inlet regulating tank in the cryogenic crystallization unit, achieving zero discharge.

[0044] The production process of this invention includes oxidizing and decomposing cumene, followed by decarbonization treatment, and then recovering phenol and acetone; the decarbonization treatment time is 15-25 minutes. The phenol-acetone wastewater generated by the production process is then treated.

[0045] like Figure 1As shown, the phenol acetone wastewater treatment process provided by the present application is as follows:

[0046] Step 1, the phenol acetone wastewater is pressurized by a pump and enters an organic metal membrane filter to remove petroleum substances and solid suspensions;

[0047] Step 2, further reduction is achieved by evaporation concentration;

[0048] Step 3, the concentrated liquid is subjected to freeze crystallization to produce sodium sulfate decahydrate;

[0049] Step 4, the sodium sulfate decahydrate obtained by freeze crystallization is subjected to dissolution and removal of organic substances and then enters an evaporation crystallizer to obtain sodium sulfate crystals.

[0050] In the above technical solution, the water quality characteristics of the phenol acetone wastewater are as follows: acetone 50-300 mg / L, petroleum substances 1-300 mg / L, COD 3000-6000 mg / L, TDS 30000-40000 mg / L, total alkali 40-50 mg / L, and temperature 70-90℃.

[0051] In step 1, the phenol acetone wastewater can directly enter the organic metal membrane filter without heat exchange, thereby reducing the heat exchange unit and shortening the treatment process. The pore size of the organic metal membrane in the organic metal membrane filter is 5-50 nm, and the flux is 20-50 LMH. The organic metal membrane filter has oil resistance, high temperature resistance, acetone resistance, and alkalinity resistance.

[0052] In step 2, the evaporation concentrator adopts one of multi-effect evaporation concentration technology and MVR evaporation concentration technology, and the preferred one is three-effect evaporation technology. The heat source uses waste heat such as factory waste heat as low-temperature heat source. After step 2, the salt content of the evaporation concentrator discharge is ≥200,000 mg / L, and the condensate is returned to the device for device production water supplement.

[0053] In step 3, the freeze crystallization device is selected from one of an FC type crystallizer, a DTB type crystallizer, or an Oslo crystallizer, and the preferred one is an FC type crystallizer. The freeze crystallization treatment conditions include a crystallization temperature of -3-0℃.

[0054] The above freeze crystallization devices are all center backflow feeding, and the sodium sulfate crystals are settled from the upper end of the cooling crystallizer, which ensures sufficient residence time and ensures that the sodium sulfate crystals grow to a sufficient size. In addition, special overflow plates are designed in the above cooling crystallizers to prevent sodium sulfate crystals from being discharged with the upper layer mother liquor. The mother liquor of the freeze crystallization device enters a mother liquor drying unit, and the miscellaneous salt formed by the mother liquor drying is concentrated and transported out for treatment.

[0055] In step 4, the organic matter removal adopts electro-catalytic oxidation treatment to remove organic matter and decolorization. In the electro-catalytic oxidation device, the anode plate is made of titanium-based material coated with a composite noble metal plating layer, and the cathode is made of stainless steel.

[0056] On the basis of the above technical solutions, in the electro-catalytic oxidation treatment, the current density is 80-300 mA / cm 2 , the electrode plate distance is 2-6 cm, and the reaction time is 3-120 minutes.

[0057] In step 4, the evaporation crystallizer is a forced circulation crystallizer, preferably an Os-Lo crystallizer; the concentrated water entering the crystallizer separation chamber is flashed to release heat in the form of water vapor. As evaporation proceeds, the concentration of the concentrated liquid increases. As the evaporation process continues, the brine in the crystallizer shell is further concentrated to produce crystallization, and the salt slurry is discharged to a centrifuge for dewatering treatment to produce sodium sulfate crystalline salt crystals, and the mother liquor is returned to the refrigerated feed water conditioning tank for re-refrigeration and crystallization, thereby improving the overall salt recovery rate of the system, and the COD content in the mother liquor is less than 2000 mg / L. The conditions for evaporation crystallization treatment include: pressure 0.4-1 MPa, feed temperature 40-60℃, evaporation temperature 50-70℃.

[0058] On the basis of the above technical solutions, the purity of the sodium sulfate salt obtained after separation and drying in step 4 is more than 98%, meeting the Class II first-class product standard in GB / T 6009-2014 "Industrial Anhydrous Sodium Sulfate". It can be recycled as a renewable resource.

[0059] In the following examples and comparative examples,

[0060] The organic metal membrane filter is a polycera Titan series spiral membrane from the United States;

[0061] The evaporation concentrator is a three-effect evaporator;

[0062] The refrigeration crystallization device is an FC type crystallizer;

[0063] The evaporation crystallizer is an Os-Lo crystallizer;

[0064] The electro-catalytic oxidation uses a Guodeng Futong ERO electro-catalytic integrated device, in which the anode plate is a titanium substrate coated with a composite noble metal plating layer, and the cathode plate is stainless steel.

[0065] Example 1

[0066] By adding a decarbonizer between the acid catalysis and the alkali neutralization in the decomposition and refining process, the alkalinity is reduced; the water and air in the decarbonizer are in contact, and the gas-water ratio is maintained at 25 m 3 air / m 3Water, residence time 20 minutes under these conditions. The water quality characteristics of the obtained phenol acetone wastewater are: water volume 10 t, acetone 100 mg / L, petroleum substances 285 mg / L, COD 6000 mg / L, TDS 36861 mg / L, SS 300 mg / L, total alkali 50 mg / L, temperature 85°C. The treatment steps are as follows:

[0067] Step 1, the phenol acetone wastewater enters the organic metal membrane filter through pump pressurization, the membrane filtration unit filtration pressure is 0.08 MPa, the membrane pore size is 0.05 μm; the filter residue is solidified and then transported out for treatment; under these conditions, the membrane flux of the membrane filtration unit is controlled at 102.4 LMH; the SS of the membrane filtration unit effluent is 35 mg / L, the petroleum substances are about 20 mg / L, the acetone is 50 mg / L, the COD is 6000 mg / L, the TDS is 36861 mg / L, and the total alkali is 50 mg / L;

[0068] Step 2, the three-effect evaporator is used for concentration and further reduction; under these conditions, the water volume is reduced from the original 10 t to 1.5 t, and the concentrated liquid is obtained: TDS 239415 mg / L, COD 32000 mg / L, total alkali 333 mg / L, SS 40 mg / L, petroleum substances about 20 mg / L, acetone 1 mg / L;

[0069] Step 3, the concentrated liquid in step 2 enters the refrigeration crystallization device for crystallization through the refrigeration water conditioning tank; the refrigeration crystallization temperature is 0°C, at which the solubility of sodium sulfate is 4.9%, and 1094 kg of sodium sulfate decahydrate is produced. The mother liquor produced by the refrigeration crystallization device enters the mother liquor drying unit for drying treatment through the spray dryer;

[0070] Step 4, the sodium sulfate decahydrate crystals obtained by refrigeration crystallization are dissolved, and then the solution is subjected to electrolysis at a current density of 300 mA / cm 2 for 3 minutes, and then enters the evaporation crystallizer for 2-effect circulating flash evaporation (temperature 60°C) to obtain sodium sulfate crystals. The mother liquor produced in the evaporation crystallizer is returned to the refrigeration water conditioning tank and then subjected to refrigeration crystallization again to improve the salt recovery rate of the whole system. After separation and drying, 400 kg of sodium sulfate salt with a purity of 99.5% is obtained, which meets the I-class product standard in the II-class standard in GB / T 6009-2014 Industrial Anhydrous Sodium Sulfate.

[0071] Example 2

[0072] A decarbonizer is added between the acid catalysis and the alkali neutralization in the decomposition refining process to reduce the alkalinity; water and air are contacted in the decarbonizer, and the gas-water ratio is maintained at 25 m 3 air / m 3Water, under this condition, the residence time is 20 minutes. The obtained phenol acetone wastewater is taken from the phenol acetone production device effluent, and the water quality characteristics are: water quantity 10 t, acetone 300 mg / L, petroleum substances 200 mg / L, COD 4697 mg / L, TDS 37373 mg / L, SS 10 mg / L, total alkali 605 mg / L, and temperature 50℃. The treatment steps are as follows:

[0073] Step 1, the phenol acetone wastewater enters the organic metal membrane filter through pump pressurization, the membrane filtration unit filtration pressure is 0.07 MPa, and the membrane pore size is 0.05 μm; the filter residue is solidified and then concentrated for external transportation and treatment; under this condition, the membrane flux of the membrane filtration unit is controlled at 102.4 LMH; the membrane filtration unit effluent petroleum is about 20 mg / L, acetone is 50 mg / L, COD is 4697 mg / L, TDS is 37373 mg / L, SS is 10 mg / L, and total alkali is 50 mg / L;

[0074] Step 2, concentrated by a three-effect evaporator, further reduced; the water quantity is reduced from the original 10 t to 1.5 t, TDS is 244847 mg / L, COD is 25012 mg / L, total alkali is 340 mg / L, SS is 10 mg / L, petroleum substances are about 20 mg / L, and acetone is 1 mg / L;

[0075] Step 3, the concentrated liquid in step 2 enters the refrigeration crystallization device for crystallization through the refrigeration water conditioning tank; the refrigeration crystallization temperature is 0℃, at this time the solubility of sodium sulfate is 4.9%, and 1013 kg of sodium sulfate decahydrate is produced. The mother liquor produced by the refrigeration crystallization device enters the mother liquor drying unit for drying treatment through the spray dryer;

[0076] Step 4, the sodium sulfate crystals obtained by refrigeration crystallization are dissolved, and then subjected to electrocatalytic oxidation reaction at a current density of 80 mA / cm 2 for 60 minutes, and then enters the 2-effect circulating flash evaporation (temperature 60℃) to obtain sodium sulfate crystals. The mother liquor produced in the evaporation crystallizer is returned to the refrigeration water conditioning tank and then subjected to refrigeration crystallization again to improve the salt recovery rate of the whole system. After separation and drying, 400 kg of sodium sulfate salt with a purity of 99.5% is obtained, which reaches the first-class product standard of type II in GB / T6009-2014 “Industrial Anhydrous Sodium Sulfate”.

[0077] Comparative Example 1

[0078] In this comparative example, the water quality characteristics of the phenol acetone wastewater treated are the same as in Example 1. The difference between Comparative Example 1 and Example 1 is that a PVDF material outer pressure type hollow fiber membrane is used for filtration before decarburization. Under the same operating conditions; the PVDF material ultrafiltration membrane has a short service life, low petroleum removal rate, and is easy to be blocked, and has a short cleaning cycle.

[0079] Comparative Example 2

[0080] In the present comparative example, the phenol acetone wastewater treated has the same quality characteristics as in Example 1. The difference between Comparative Example 1 and Example 1 is that the decarbonator is placed after the metallic membrane filter. As a result, it is found that the energy consumption of the evaporation and concentration preheating stage is increased, and the generation of impurities in the mother liquor is increased.

[0081] Any numerical values recited herein include all values from the lower value and up to the upper value. Values that are near to or fall within a range provided in the written description should be considered to be within the range. Any numerical value, however, can only be precise to the tenth unless otherwise indicated. In this application, the use of "about" means that a value can be "exactly" the value or approximately the value. For example, "about 90% can mean the value is exactly 90% or the value is approximately 90%. Any reference to a process variable, such as temperature, pressure, time, etc., is intended to include all values from the lower value and up to the upper value. For example, if a process variable is stated to be 50-90, it is intended that all values from 51-89, 52-88, etc., and 69-71, 70-71, etc., are specifically contemplated. For non-integer values, 0.1, 0.01, 0.001, or 0.0001 can be considered as a unit. This is only a few specific examples. In a similar manner, all possible combinations of the range of values between a lowest value and a highest value are to be considered to be expressly disclosed. For example, the statement that a process variable is 50-90 is intended to expressly disclose 50-90, 51-89, 52-88, etc., and 69-71, 70-71, etc.

[0082] It should be noted that the foregoing examples have been provided merely for the purpose of explanation and are in no way to be construed as limiting of the present application. While the application has been described with reference to exemplary embodiments, it is understood that the words that have been used herein are words of description, and that they are being used under the description and explanation of the application. Modifications can be made to the application in light of these teachings. The application can be used in conjunction with any other patent application to provide claimed subject matter. While the application has been described as related to a particular use, it is understood that no limitation of the scope of the application arises therefrom. Contrarily, it is submitted with the general knowledge of the art that the application is capable of further modifications. Although the application herein described has been described with regard to particular embodiments thereof, all modifications coming within the scope of the appended claims are to be included therein.

Claims

1. A phenol acetone production and wastewater treatment system comprising a production system and a wastewater treatment system; the production system comprising a reactor, an evaporator, a decomposition kettle, a neutralization kettle, a water washing tower and a distillation tower connected in sequence by pipelines, characterized in that, A decarbonizer is arranged between the decomposition kettle and the neutralization kettle; the wastewater produced by the production system enters a wastewater treatment system through a pipeline; The wastewater treatment system comprises, in sequence through a pipeline, an organic metal membrane filter, an evaporation concentrator, a refrigerated feed water adjusting tank, a refrigerated crystallization device, an electro-catalytic oxidation device, and an evaporation crystallizer; The refrigerated crystallization device comprises a mother liquor outlet I, and the mother liquor outlet I is connected with a mother liquor drying unit; The evaporation crystallizer comprises a mother liquor outlet II, and the mother liquor outlet II is in communication with the refrigerated feed water adjusting tank; The pore size of the membrane material in the organic metal membrane filter is 5-50 nm, and the flux is 20-150 LMH; The organic metal membrane filter is used to remove petroleum substances and suspended solids in the phenol acetone wastewater.

2. The system of claim 1, wherein, The decarboxilator is selected from a blast decarboxilator; the air / water ratio inside the decarboxilator is between 20 and 35 m 3 air / m 3 water.

3. The system of claim 1 or 2, wherein, The evaporation concentrator is selected from a multi-effect evaporation concentrator or an MVR evaporation concentrator; And / or, the refrigerated crystallization device is selected from an FC type crystallizer, a DTB type crystallizer, or an Oslo crystallizer.

4. The system of claim 1 or 2, wherein, The electro-catalytic oxidation device is provided with an anode plate and a cathode plate, and the distance between the anode plate and the cathode plate is 2-6 cm.

5. The system of claim 4, wherein, The material of the anode plate is selected from any one of noble metals, metal oxides, metal matrix composites, or diamonds; And / or, the material of the cathode is selected from any one of carbon, carbon-based composites, noble metals, metal oxides, or stainless steel.

6. The system of claim 1 or 2, wherein, The content of bicarbonate in the wastewater produced by the production system is not more than 50 mg / L.

7. A process for the production of phenol and acetone and the treatment of wastewater using the system described in any one of claims 1 to 6, characterized in that, The production process comprises the following steps: oxidizing and decomposing cumene, then performing decarbonization treatment, and then recovering and treating to obtain phenol and acetone; and the phenol acetone wastewater produced by the production process is subjected to wastewater treatment; The wastewater treatment process comprises the following steps: (1) filtering to remove petroleum substances and suspended solids in the phenol acetone wastewater; (2) performing refrigerated crystallization after evaporation concentration; (3) removing organic matter and performing evaporation crystallization to obtain sodium sulfate crystals.

8. The process of claim 7, wherein, The decarbonization treatment time is 15-25 minutes; And / or, in step (2), the salt content of the discharge after evaporation concentration is ≥200,000 mg / L; And / or, in step (2), the refrigerated crystallization temperature is -3-0℃.

9. The process according to any one of claims 7 to 8, characterized in that, In step (3), the organic matter is removed by electro-catalytic oxidation treatment, and the current density of the electro-catalytic oxidation treatment is 80-300 mA / cm 2 , and the reaction time is 3-120 minutes. And / or, in step (3), the evaporation crystallization conditions include: pressure 0.4 Mpa-1 Mpa, feed temperature 40℃-60℃, and evaporation temperature 50℃-70℃.

10. The process according to any one of claims 7 to 8, characterized in that, The water quality characteristics of the phenol acetone wastewater are: acetone 50-300 mg / L, petroleum substances 1-300 mg / L, COD 3000-6000 mg / L, TDS 30000-40000 mg / L, total alkali 40-50 mg / L, and temperature 70-90℃; And / or, the purity of the sodium sulfate crystals is not less than 98%.

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