Method for desalting and dewatering emulsified nitrobenzene

Abstract

The invention relates to an emulsified nitrobenzene desalination and water removal method, which comprises the following steps of: pressurizing emulsified nitrobenzene by using a reinforced separation tank, a booster pump and a membrane separation assembly, filtering the pressurized emulsified nitrobenzene by using an organic-inorganic composite membrane modified by a hydrophobic organic matter, and refining the nitrobenzene from which saline water is removed, the brine-rich nitrobenzene is returned to the enhanced separation tank, the brine and the nitrobenzene are separated under the action of hydrophilic and hydrophobic fibers and particles in an enhanced separation area, and the brine containing a small amount of nitrobenzene is subjected to organic matter recovery in a nitrobenzene stripping tower. The device is especially suitable for dehydration and desalination after alkali washing of crude nitrobenzene water in the nitrobenzene production process, and has the advantages of simple device flow, stable operation and high dehydration and desalination efficiency.

Description

Technical Field

[0001] The invention discloses a method for desalting and removing water from emulsified nitrobenzene, belonging to the field of chemical product refining and purification, and specifically relates to a method for separating brine from crude nitrobenzene after water alkali washing in the process of producing nitrobenzene by nitration of benzene. Background Art

[0002] Nitrobenzene is generally produced by the reaction of benzene with mixed acid, and the mixed acid nitration product is crude nitrobenzene. Crude nitrobenzene usually contains residual acid and nitrophenol by-products, among which the residual nitrophenol will bring danger to the subsequent process and must be removed. In order to reduce the risk of residual nitrophenol in industry, alkali washing, water washing and other steps are required to convert the nitrophenol in crude nitrobenzene into sodium salt and transfer it from the organic phase to the aqueous phase. At the same time, the residual mixed acid is also converted into sodium salt and most of it is transferred to the aqueous phase.

[0003] However, after nitrobenzene is separated from alkali washing and water washing, the organic phase is in an emulsified state, and the residual water and sodium salt exist in the form of oil-in-water. Moreover, it is extremely difficult to demulsify due to the small particle size of the emulsified liquid. After this part of residual sodium salt enters the refining system after preheating, it will accumulate in the preheater and the distillation tower kettle during long-term operation and needs to be cleaned every day. It will also scale in the primary distillation tower, the distillation tower kettle and the reboiler, increasing the frequency of tar extraction and affecting the continuous production and production cost of the device. Frequent operation not only causes production fluctuations but also wastes a lot of manpower and material resources. At the same time, the enrichment of sodium salt in tar greatly increases the production of nitrobenzene tar, resulting in additional hazardous waste treatment costs.

[0004] The particle size of emulsified nitrobenzene droplets was measured under a microscope after standing for 5 hours, and the total number of emulsified droplets was 1.665 million / ml, of which droplets below 5 μm accounted for 81%, droplets of 5-15 μm accounted for about 17.5%, droplets of 15-25 μm accounted for about 1.5%, and droplets above 25 μm accounted for less than 0.1%.

[0005] In order to reduce the sodium salt content in crude nitrobenzene, technicians in this field have made many attempts, such as using enhanced water alkali washing, agglomeration separation, etc.

[0006] CN106278902B discloses a method for reducing the sodium salt content in crude nitrobenzene. The main idea is to increase the water-to-oil ratio by increasing the washing water and alkali solution so as to dissolve as much sodium salt as possible into the water phase.

[0007] CN103664629B discloses a nitrobenzene washing and separation system, which allows the neutralized and water-washed nitrobenzene organic phase to enter a coalescing separator integrated with a fiber filter element, a plate separator, a combined separator, etc., to further remove sodium salts and phenol salts in the organic phase.

[0008] CN1757630A discloses a nitrobenzene washing production device and a washing production method, which uses a tubular washer and relies on gravity sedimentation for separation. The effect of using enhanced water alkali washing is limited, the emulsification of nitrobenzene cannot be improved, and the entrainment of sodium salt and phenol salt cannot be solved. The emulsified nitrobenzene is treated with a coalescing separator, and the effect is good in the initial operation. However, as the operation time increases, sodium salt and phenol salt accumulate and clog the fibers and plate holes, eventually causing excessive pressure difference and having to be stopped.

[0009] Ceramic membranes based on inorganic material science have advantages that cannot be matched by separation media such as filter presses, centrifuges, diatomaceous earth and polymer membranes, such as good chemical stability, high mechanical strength, large processing capacity, high separation accuracy and easy cleaning. Therefore, they have good development prospects in recent years and have been successfully used in the separation of various products. Modification of ceramic membranes with hydrophobic organic modification materials can effectively remove water from organic solvents.

[0010] The present invention can perform continuous dehydration and desalination operations on emulsified nitrobenzene, and the brine is continuously discharged from the system. Since a backwash water inlet, a backwash water outlet and a spherical one-way valve group are provided, the particles and fibers in the enhanced separation zone can be cleaned regularly to prevent clogging by salt and other particulate impurities. The invention has the advantages of high desalination and dehydration efficiency, good operation stability and simple process. Summary of the invention

[0011] The object of the present invention is to provide a method for desalting and removing water from emulsified nitrobenzene. Based on the characteristics that emulsified nitrobenzene after water alkali washing contains a certain amount of sodium salt and water, an inorganic ceramic membrane modified by hydrophobic organic matter is used as a composite membrane separation component, and the emulsified nitrobenzene is pressurized and then subjected to membrane separation, dehydration and desalination. The nitrobenzene after removing the brine is sent to a refining system, and the nitrobenzene enriched with brine is returned to a reinforced separation tank, and the brine containing a small amount of nitrobenzene is sent to a nitrobenzene stripping tower through a brine outlet arranged at the bottom of the reinforced separation tank to further recover nitrobenzene.

[0012] The present invention is implemented as follows: an emulsified nitrobenzene desalination and dewatering method, using a reinforced separation tank as a reinforced separation device for brine and organic phase in nitrobenzene, emulsified nitrobenzene containing water and inorganic sodium salt after water alkali washing is pressurized and sent to a membrane separation component, a composite membrane with an inorganic porous ceramic membrane as a support layer and an organic hydrophobic modified layer as a separation layer is used to separate the brine in the emulsified nitrobenzene, the nitrobenzene with brine removed on the permeate side is refined, and the nitrobenzene emulsion enriched with brine on the interception side is returned to the reinforced separation tank for separation of brine and nitrobenzene, and a brine solution containing a small amount of nitrobenzene at the bottom of the reinforced separation tank is sent to recover the nitrobenzene in the brine.

[0013] Generally, the emulsified nitrobenzene desalination and water removal method adopts an enhanced separation tank, a nitrobenzene booster pump, and a membrane separation component to achieve the removal of brine from nitrobenzene, wherein the organic phase outlet of the enhanced separation tank is connected to the inlet of the nitrobenzene booster pump, the outlet of the nitrobenzene booster pump is connected to the inlet of the membrane separation component, and the brine-rich nitrobenzene on the retention side of the membrane separation component is connected to the membrane separation return liquid inlet of the enhanced separation tank.

[0014] The enhanced separation tank comprises, from top to bottom, a feed buffer zone, an organic phase static zone, a primary enhanced separation zone, an enhanced separation intermediate zone, a secondary enhanced separation zone, and a brine clarification zone.

[0015] The feed buffer area of ​​the enhanced separation tank is provided with a spherical one-way valve group, and the emulsified nitrobenzene flows downward into the organic phase static area through the one-way valve group.

[0016] The organic phase static zone of the enhanced separation tank is provided with an organic phase outlet and a backwash water outlet.

[0017] The primary enhanced separation zone of the enhanced separation tank adopts a mixture of spherical or other shaped hydrophilic particles and hydrophobic particles with a particle size of 0.1 mm to 3 mm.

[0018] The hydrophilic particles include but are not limited to ceramics, kaolin, alumina, silicon oxide, zirconium oxide, and titanium oxide; the hydrophobic particles include but are not limited to polyethylene, polyvinyl chloride, polystyrene, polypropylene, polytetrafluoroethylene and other fluorine-containing polymers.

[0019] The enhanced separation middle zone of the enhanced separation tank is provided with a membrane separation return liquid inlet.

[0020] The secondary enhanced separation zone of the enhanced separation tank adopts a mesh filler woven with hydrophilic fiber: hydrophobic fiber in a ratio of 1:1.

[0021] The hydrophilic fibers include but are not limited to natural fibers such as silk, wool, rabbit hair, cotton, linen and synthetic fibers such as viscose; the hydrophobic fibers include but are not limited to polyester, nylon, spandex, polypropylene and chloroprene.

[0022] The brine clarification zone of the enhanced separation tank is provided with a backwash water inlet and a brine outlet.

[0023] The membrane material of the membrane separation component adopts an organic-inorganic composite membrane, which includes a support layer and a separation layer. The support layer is one of α-alumina and β-alumina, and the separation layer is an organic hydrophobic modified layer, which is one of aluminum oxide, zirconium oxide, titanium oxide, and silicon oxide through hydrophobic organic grafting modification.

[0024] The hydrophobic organic substance is selected from one of octadecyltrimethoxysilane, tridecyltrimethoxysilane, hexadecyltrimethoxysilane, octadecyltrichlorosilane, n-butyldimethylchlorosilane, trimethylchlorosilane and octylchlorosilane.

[0025] Advantages and effects of the present invention: The method for desalting and removing water from emulsified nitrobenzene of the present invention combines enhanced separation equipment with membrane separation components, and pressurizes the emulsified nitrobenzene and filters and permeates through an inorganic ceramic composite membrane that has been hydrophobically modified to separate nitrobenzene from brine, and discharges the nitrobenzene from the permeation side of the separation membrane. Nitrobenzene rich in brine is demulsified and aggregated under the action of hydrophilic and hydrophobic particles and hydrophilic and hydrophobic fibers arranged in the enhanced separation zone of the enhanced separation tank, and the brine is separated from the emulsion and discharged from the bottom of the enhanced separator. Compared with traditional water alkali washing desalination and coalescence separation dehydration desalination, the present invention has the advantages of simple process, stable operation, and high dehydration and desalination efficiency, and is particularly suitable for the dehydration and desalination of emulsified nitrobenzene after water alkali washing of crude nitrobenzene in nitrobenzene production. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The present invention is a schematic diagram of the process flow of the emulsified nitrobenzene desalination and water removal method.

[0027] In the figure, 1 is an enhanced separation tank, 2 is a nitrobenzene booster pump, and 3 is a membrane separation component.

[0028] Figure 2 It is a schematic diagram of the structure of the enhanced separation tank in the embodiment.

[0029] In the figure, 1-1 is the inlet of emulsified nitrobenzene, 1-2 is the spherical one-way valve group, 1-3 is the outlet of backwash water, 1-4 is the inlet of membrane separation return liquid, 1-5 is the outlet of brine, 1-6 is the feed buffer zone, 1-7 is the organic phase static zone, 1-8 is the organic phase outlet, 1-9 is the primary enhanced separation zone, 1-10 is the enhanced separation intermediate zone, 1-11 is the secondary enhanced separation zone, 1-12 is the inlet of backwash water, and 1-13 is the brine clarification zone.

[0030] Figure 3 This is a comparison diagram of the states of emulsified nitrobenzene before and after passing through the membrane separation component in the embodiment.

[0031] In the figure, the bottle on the right shows the state of emulsified nitrobenzene before passing through the membrane separation component, and the bottle on the left shows the state after passing through the membrane separation component. Implementation

[0032] The present invention will be further described below in conjunction with embodiments and drawings. Example

[0033] A method for desalting and removing water from emulsified nitrobenzene Figure 1, an enhanced separation tank 1 is used as an enhanced separation device for the brine and the organic phase in nitrobenzene. The emulsified nitrobenzene containing water and inorganic sodium salt after water alkali washing is pressurized by a booster pump 2 and then sent to a membrane separation component 3. A composite membrane with an inorganic porous ceramic membrane as a support layer and an organic hydrophobic modified layer as a separation layer is used to separate the brine in the emulsified nitrobenzene. The nitrobenzene in the brine is removed on the permeate side for refinement, and the nitrobenzene emulsion enriched with brine on the interception side is returned to the enhanced separation tank for separation of brine and nitrobenzene. The brine solution containing a small amount of nitrobenzene at the bottom of the enhanced separation tank is sent to recover the nitrobenzene in the brine.

[0034] In the embodiment, an enhanced separation tank 1, a nitrobenzene booster pump 2, and a membrane separation component 3 are used to remove brine from nitrobenzene, wherein the organic phase outlet of the enhanced separation tank 1 is connected to the inlet of the nitrobenzene booster pump 2, the outlet of the nitrobenzene booster pump 2 is connected to the inlet of the membrane separation component 3, and the brine-rich nitrobenzene on the retention side of the membrane separation component 3 is connected to the membrane separation return liquid inlet of the enhanced separation tank 1.

[0035] The enhanced separation tank structure in the embodiment is shown in the attached Figure 2 , from top to bottom are feed buffer zone 1-6, organic phase static zone 1-7, primary enhanced separation zone 1-9, enhanced separation intermediate zone 1-10, secondary enhanced separation zone 1-11, and brine clarification zone 1-13.

[0036] The feed buffer area 1-6 of the enhanced separation tank is provided with a spherical one-way valve group 1-2, and the emulsified nitrobenzene flows downward into the organic phase static area 1-7 through the one-way valve group. The organic phase static area is provided with an organic phase outlet 1-8 and a backwash water outlet 1-3.

[0037] The primary enhanced separation zone 1-9 of the enhanced separation tank uses a mixture of hydrophilic particles and hydrophobic particles in spherical or other shapes with a particle size of 0.1 mm to 3 mm.

[0038] The enhanced separation intermediate zone 1-10 of the enhanced separation tank is provided with a membrane separation return liquid inlet 1-4.

[0039] The secondary enhanced separation zone 1-11 of the enhanced separation tank adopts a mesh filler woven with hydrophilic fiber: hydrophobic fiber = 1:1 ratio.

[0040] The brine clarification zone 1-13 of the enhanced separation tank is provided with a backwash water inlet 1-12 and a brine outlet 1-5.

[0041] Embodiment: In the desalination and dewatering method of emulsified nitrobenzene, during normal operation, the backwash water inlet and outlet are closed, and the emulsified nitrobenzene enters the feed buffer of the enhanced separation tank, and then enters the organic phase static zone through the spherical one-way valve group, and enters the nitrobenzene booster pump from the organic phase outlet set in the organic phase static zone, and then is introduced into the membrane separation component from the outlet of the nitrobenzene booster pump, and the brine-rich nitrobenzene of the membrane separation component returns to the membrane separation return liquid inlet set in the enhanced separation middle zone, and after passing through the primary enhanced separation zone and the secondary enhanced separation zone, the brine and nitrobenzene are separated and discharged from the brine outlet set at the bottom of the brine clarification zone, and sent to the nitrobenzene stripping tower. The permeate side of the membrane separation component is nitrobenzene with the brine removed, which is sent for refining.

[0042] In the embodiment of the emulsified nitrobenzene desalination and water removal method, when backwashing is required, the backwash water is connected from the backwash water inlet, passes through the brine clarification zone, enters the secondary enhanced separation zone to dissolve the inorganic salts accumulated in the fiber mesh, and then enters the primary enhanced separation zone through the enhanced separation intermediate zone to dissolve the inorganic salts accumulated in the small particles, and then enters the organic phase static zone. The water flow from bottom to top impacts the spherical one-way valve group set in the feed buffer zone, so that the valve is closed, and the water flow is discharged from the backwash water outlet set in the organic phase static zone and mixed with the brine outlet and then sent to the nitrobenzene stripping tower. Example 1

[0043] The emulsified nitrobenzene after water alkali washing in a 50,000 tons / year nitrobenzene plant was tested to have a water content of 1% and a sodium ion content of 20 mg / L. Using the embodiment device, a mixture of 0.2 mm ceramic and 0.5 mm polyethylene particles was set in the first-level enhanced separation zone of the enhanced separation tank, with a weight ratio of 1:1; a mesh filler made of hydrophilic natural fiber wool and hydrophobic fiber polyester was set in the second-level enhanced separation zone of the enhanced separation tank. The membrane material of the membrane separation component adopts an organic-inorganic composite membrane, the supporting layer is α-alumina, and the separation layer is made of silicon oxide modified by octaalkyltrimethoxysilane. After the emulsified nitrobenzene is separated by the membrane separation component, the water content of the nitrobenzene removed from the brine on the permeate side is measured to be reduced to 0.2%, and the sodium ion is reduced to 5.3 mg / L. Example 2

[0044] The emulsified nitrobenzene after water alkali washing in a 100,000 tons / year nitrobenzene plant was tested to have a water content of 1.5% and a sodium ion content of 35 mg / L. Using the embodiment device, a mixture of 0.1 mm ceramic and 1.5 mm polyvinyl chloride particles was set in the first-level enhanced separation zone of the enhanced separation tank, with a weight ratio of 1:1; a mesh filler made of hydrophilic natural fiber rabbit hair and hydrophobic fiber spandex was set in the second-level enhanced separation zone of the enhanced separation tank. The membrane material of the membrane separation component adopts an organic-inorganic composite membrane, the supporting layer is α-alumina, and the separation layer is made of alumina modified by hexadecyltrimethoxysilane. After the emulsified nitrobenzene is separated by the membrane separation component, the water content of the nitrobenzene removed from the brine on the permeate side is measured to be reduced to 0.45%, and the sodium ion is reduced to 8.2 mg / L. Example 3

[0045] The emulsified nitrobenzene after water alkali washing in a 100,000 tons / year nitrobenzene plant was tested to have a water content of 0.8% and a sodium ion content of 18 mg / L. Using the embodiment device, a mixture of 1.0 mm ceramic and 0.1 mm polypropylene particles was set in the first-level enhanced separation zone of the enhanced separation tank, with a weight ratio of 1:1; a mesh filler woven from hydrophilic natural fiber hemp and hydrophobic fiber nylon was set in the second-level enhanced separation zone of the enhanced separation tank. The membrane material of the membrane separation component adopts an organic-inorganic composite membrane, the supporting layer is β-alumina, and the separation layer is made of zirconium oxide modified by tridecyltrimethoxysilane. After the emulsified nitrobenzene is separated by the membrane separation component, the water content of the nitrobenzene removed from the brine on the permeate side is measured to be reduced to 0.17%, and the sodium ion is reduced to 4.9 mg / L. Example 4

[0046] The emulsified nitrobenzene after water alkali washing in a 150,000 tons / year nitrobenzene plant was tested to have a water content of 1.2% and a sodium ion content of 26 mg / L. Using the embodiment device, a mixture of 0.5 mm titanium oxide and 2 mm polystyrene particles was set in the first-level enhanced separation zone of the enhanced separation tank, with a weight ratio of 1:1; a mesh filler made of hydrophilic natural fiber silk and hydrophobic fiber polypropylene was set in the second-level enhanced separation zone of the enhanced separation tank. The membrane material of the membrane separation component adopts an organic-inorganic composite membrane, the supporting layer is β-alumina, and the separation layer is made of silicon oxide modified by octadecyltrichlorosilane. After the emulsified nitrobenzene is separated by the membrane separation component, the water content of the nitrobenzene removed from the brine on the permeate side is measured to be reduced to 0.31%, and the sodium ion is reduced to 7.3 mg / L. Example 5

[0047] The emulsified nitrobenzene after water alkali washing in a 100,000 tons / year nitrobenzene plant was tested to have a water content of 1.8% and a sodium ion content of 41 mg / L. Using the embodiment device, a mixture of 3mm kaolin and 0.3mm polytetrafluoroethylene particles was set in the first-level enhanced separation zone of the enhanced separation tank, with a weight ratio of 1:1; a mesh filler woven from hydrophilic natural fiber cotton and hydrophobic fiber polyester was set in the second-level enhanced separation zone of the enhanced separation tank. The membrane material of the membrane separation component adopts an organic-inorganic composite membrane, the supporting layer is α-alumina, and the separation layer is made of titanium oxide modified by n-butyldimethylchlorosilane. After the emulsified nitrobenzene is separated by the membrane separation component, the water content of the nitrobenzene removed from the brine on the permeate side is measured to be reduced to 0.46%, and the sodium ion is reduced to 8.6 mg / L. Example 6

[0048] The emulsified nitrobenzene after water alkali washing in a 200,000 tons / year nitrobenzene plant was tested to have a water content of 0.9% and a sodium ion content of 15 mg / L. Using the embodiment device, a mixture of 3 mm silicon oxide and 0.3 mm polyvinylidene fluoride particles was set in the first-level enhanced separation zone of the enhanced separation tank, with a weight ratio of 1:1; a mesh filler woven from hydrophilic natural fiber cotton and hydrophobic fiber chlorofiber was set in the second-level enhanced separation zone of the enhanced separation tank. The membrane material of the membrane separation component adopts an organic-inorganic composite membrane, the supporting layer is α-alumina, and the separation layer is made of alumina modified by trimethylchlorosilane. After the emulsified nitrobenzene is separated by the membrane separation component, the water content of the nitrobenzene removed from the brine on the permeate side is measured to be reduced to 0.35%, and the sodium ion is reduced to 4.1 mg / L. Example 7

[0049] The emulsified nitrobenzene after water alkali washing in a 50,000 tons / year nitrobenzene plant was tested to have a water content of 1.6% and a sodium ion content of 26 mg / L. The embodiment device is used, and a mixture of 1.5 mm zirconium oxide and 0.6 mm polypropylene particles is set in the first-level enhanced separation zone of the enhanced separation tank, with a weight ratio of 1:1; a mesh filler made of hydrophilic synthetic fiber viscose fiber and hydrophobic fiber polypropylene is set in the second-level enhanced separation zone of the enhanced separation tank. The membrane material of the membrane separation component adopts an organic-inorganic composite membrane, the supporting layer is β-alumina, and the separation layer is made of titanium oxide modified by octylchlorosilane. After the emulsified nitrobenzene is separated by the membrane separation component, the water content of the nitrobenzene removed from the brine on the permeate side is measured to be reduced to 0.40%, and the sodium ion is reduced to 7.5 mg / L.

[0050] The present invention uses a nitrobenzene booster pump to boost the pressure of the emulsified nitrobenzene after water alkali washing and then feeds it into a composite membrane separation component modified by an inorganic ceramic membrane and a hydrophobic organic matter, removes the nitrobenzene from the brine and goes to the refining system, and the nitrobenzene rich in brine returns to the enhanced separation tank for enhanced separation, and the brine is discharged from the system to the nitrobenzene stripping tower through the brine outlet at the bottom of the brine clarification zone of the enhanced separation tank. The present invention not only has high efficiency in removing brine from the emulsified nitrobenzene, but also can operate continuously and stably for a long time, and is simpler than the water alkali washing enhanced process and is easy to operate. It is particularly suitable for desalting and dehydrating emulsified nitrobenzene after water alkali washing in the nitrobenzene production process.

Claims

1. A method for desalting and dewatering emulsified nitrobenzene, characterized in that An enhanced separation tank is used as an enhanced separation device for the brine and organic phase in nitrobenzene. The emulsified nitrobenzene after water alkali washing is pressurized and sent to the membrane separation component. A composite membrane with an inorganic porous ceramic membrane as a support layer and an organic hydrophobic modified layer as a separation layer is used to separate the brine in the emulsified nitrobenzene. The nitrobenzene in the brine is removed on the permeate side for refinement, and the nitrobenzene emulsion enriched with brine on the interception side is returned to the enhanced separation tank for separation of brine and nitrobenzene. The brine solution containing a small amount of nitrobenzene at the bottom of the enhanced separation tank is sent to recover the nitrobenzene in the brine.

2. A method for desalting and dewatering emulsified nitrobenzene according to claim 1, characterized in that The enhanced separation tank comprises, from top to bottom, a feed buffer zone, an organic phase static zone, a primary enhanced separation zone, an enhanced separation intermediate zone, a secondary enhanced separation zone, and a brine clarification zone.

3. A method for desalting and dewatering emulsified nitrobenzene according to claim 2, characterized in that The feed buffer area of ​​the enhanced separation tank is provided with a spherical one-way valve group, and the emulsified nitrobenzene enters the organic phase static area downward through the one-way valve group; the organic phase static area is provided with an organic phase outlet and a backwash water outlet.

4. A method for desalting and dewatering emulsified nitrobenzene according to claim 2, characterized in that The first-stage enhanced separation zone of the enhanced separation tank uses a mixture of hydrophilic particles and hydrophobic particles in spherical or other shapes with a particle size of 0.1mm~3mm.

5. A method for desalting and dewatering emulsified nitrobenzene according to claim 4, characterized in that The hydrophilic particles are selected from one or more of ceramics, kaolin, alumina, silicon oxide, zirconium oxide, and titanium oxide, and the hydrophobic particles are selected from one or more of polyethylene, polyvinyl chloride, polystyrene, polypropylene, polytetrafluoroethylene, and other fluorine-containing polymers.

6. A method for desalting and dewatering emulsified nitrobenzene according to claim 2, characterized in that The enhanced separation middle zone of the enhanced separation tank is provided with a membrane separation return liquid inlet; the brine clarification zone of the enhanced separation tank is provided with a backwash water inlet and a brine outlet.

7. A method for desalting and dewatering emulsified nitrobenzene according to claim 2, characterized in that The secondary enhanced separation zone of the enhanced separation tank adopts a mesh filler woven with hydrophilic fiber: hydrophobic fiber = 1:1 ratio.

8. A method for desalting and dewatering emulsified nitrobenzene according to claim 7, characterized in that The hydrophilic fiber is selected from one or more of natural fibers such as silk, wool, rabbit hair, cotton silk, linen silk and synthetic fiber viscose fiber; the hydrophobic fiber is selected from one or more of polyester, nylon, spandex, polypropylene and chloroprene.

9. A method for desalting and dewatering emulsified nitrobenzene according to claim 2, characterized in that The membrane material of the membrane separation component adopts an organic-inorganic composite membrane, which includes a support layer and a separation layer. The support layer is one of α-alumina and β-alumina, and the separation layer is an organic hydrophobic modified layer, which is one of aluminum oxide, zirconium oxide, titanium oxide, and silicon oxide through hydrophobic organic grafting modification.

10. The method for desalting and removing water from emulsified nitrobenzene according to claim 9, characterized in that The hydrophobic organic matter is selected from one of octadecyltrimethoxysilane, tridecyltrimethoxysilane, hexadecyltrimethoxysilane, octadecyltrichlorosilane, n-butyldimethylchlorosilane, trimethylchlorosilane and octylchlorosilane.

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