A coalescence and demulsification device and method based on electret electrostatic field

Abstract

The present invention discloses a coalescence and demulsification device and method based on an electret electrostatic field, wherein the coalescence and demulsification device comprises a shell, a liquid distribution tray, a boiling stop baffle, a multi-media coalescence module, an enhanced sedimentation module, and an electret module arranged on both sides of the multi-media coalescence module and at the same height as the multi-media coalescence module, wherein the liquid distribution tray is externally connected to a liquid inlet, and an oil outlet and a water outlet are arranged on the shell corresponding to the enhanced sedimentation module. The device uses an electret module to replace the traditional electrode assembly of an external active high-voltage power supply to generate an electrostatic field. After electret charging, the electret module can generate an electrostatic field without an external power supply, making the structure of the demulsification device simpler and more compact; in addition, the electret is a permanent body, which can be used for a long time after being electret once, and greatly reduces energy consumption compared to the traditional electrode assembly of an external power supply, and has good economic benefits.

Description

Technical Field

[0001] The invention belongs to the field of oil-water separation in petrochemical industry, and in particular relates to a coalescence and demulsification device and method based on an electret electrostatic field. Background Art

[0002] In the fields of petrochemicals, coal chemical industry, etc., W / O emulsions and O / W emulsions are widely present. For example, in oil fields, after rough separation of downhole produced fluid, water-containing crude oil (i.e., W / O emulsion) and oil-containing produced water (i.e., O / W emulsion) will be obtained. In refineries, the oil products after distillation contain water (i.e., W / O emulsion), and the wastewater after condensation of oil gas and water vapor contains oil (i.e., O / W emulsion). For W / O emulsions, the water contained in them can cause equipment corrosion, increased transportation costs, and catalyst deactivation during processing; for O / W emulsions, if they are not separated and treated, they will cause serious pollution to the environment. Therefore, companies have a wide demand for emulsion dehydration or oil removal purification technology.

[0003] In the prior art, the demulsification device using the synergistic effect of electric field and medium shows a significant enhanced separation effect, which is significantly better than the treatment effect of single electric field or medium agglomeration in terms of demulsification rate and separation depth. However, the existing electric-dielectric synergistic demulsification devices need to rely on an external high-voltage power supply to generate an electrostatic field, which makes the device and process more complicated and energy-intensive. For example, CN112505302A discloses a continuous flow electric field synergistic medium agglomeration demulsification effect evaluation system, in which an electrode assembly composed of rod-shaped electrodes is connected to an external power supply to generate an electrostatic field; CN112500886A discloses a method and device for enhancing oil dehydration by electric field synergistic medium agglomeration, which is also an electrode assembly composed of multiple electrodes connected to an external power supply system to generate an electrostatic field.

[0004] In order to solve the above-mentioned problems in the prior art, the present invention provides a coagulation and demulsification device based on the electret electrostatic field, which uses an electret to replace the traditional active high-voltage power supply to generate the electrostatic field. While ensuring that the demulsification device has a strong demulsification ability, the demulsification device is simpler, safer, more compact and energy-saving. Summary of the invention

[0005] In order to solve the deficiencies of the prior art, the present invention provides a coagulation and demulsification device and method based on an electret electrostatic field.

[0006] To achieve the above object, the present invention adopts the following technical solution:

[0007] A coalescence and demulsification device based on an electret electrostatic field, the coalescence and demulsification device comprising a shell, a liquid distribution tray, a boiling stop baffle, a multi-media coalescence module, an enhanced sedimentation module arranged in sequence inside the shell, and an electret module arranged on both sides of the multi-media coalescence module and at the same height as the multi-media coalescence module, the liquid distribution tray is externally connected to a liquid inlet, and the shell corresponding to the enhanced sedimentation module is provided with an oil outlet and a water outlet, wherein:

[0008] The multi-media coalescing module is uniformly filled with several kinds of coalescing media, and a support plate is arranged at the bottom of the coalescing media; the electret module includes a waterproof medium layer, an electret film, a first electrode layer and a first substrate layer, which are located on one side of the multi-media coalescing module and are tightly attached from the inside to the outside, and a second electrode layer located on the other side of the multi-media coalescing module, wherein the first substrate layer and the second electrode layer are tightly attached to the inner wall of the shell, and the second electrode layer is arranged opposite to the waterproof medium layer.

[0009] Furthermore, when the treatment object of the coalescing and demulsifying device is W / O emulsion, the interior of the shell of the coalescing and demulsifying device is, from top to bottom, a liquid distribution tray, a boiling stop baffle, a multi-media coalescing module and an enhanced sedimentation module; an oil outlet is provided on the shell on the right side of the enhanced sedimentation module, and a water outlet is provided on the shell at the bottom of the enhanced sedimentation module; a backwash inlet is provided on the left side of the shell between the multi-media coalescing module and the enhanced sedimentation module, a backwash outlet is provided on the top of the shell, and a backwash anti-escape component is provided at the backwash outlet.

[0010] Furthermore, when the treatment object of the coagulation and demulsification device is O / W emulsion, the interior of the shell of the coagulation and demulsification device is, from bottom to top, a liquid distribution tray, a boiling stop baffle, a multi-media coagulation module and an enhanced sedimentation module, and the shell on the right side of the enhanced sedimentation module is provided with a water outlet and an oil outlet from top to bottom; a backwash inlet is provided on the left side of the shell on the upper part of the enhanced sedimentation module, a backwash outlet is provided at the bottom of the shell, and a backwash anti-escape component is provided at the backwash outlet.

[0011] Furthermore, a feed port and a discharge port are respectively provided on both sides of the shell at the top of the multi-media coalescing module; when the coalescing and demulsifying device processes W / O emulsion, a pressure gauge is provided on the top of the shell, a differential pressure gauge is provided on the top of the multi-media coalescing module, and a level gauge is provided at the outlet of the enhanced sedimentation module; when the coalescing and demulsifying device processes O / W emulsion, a pressure gauge is provided on the bottom of the shell, and a differential pressure gauge is provided on the top of the multi-media coalescing module.

[0012] Furthermore, the coalescence and demulsification device is a rectangular parallelepiped, with a length and width of 80-100 mm and a height of 360-400 mm. The material of the waterproof medium layer is PP, PTFE or PMMA, and its thickness is 10 μm-8 mm. The material of the electret film is one or more of PE, PP, PTFE, PMMA, FEP, teflon AF, PFA, PCTEF, ETFE, PI, PET, COC, PVDF and P (VDF-TrFE); the multi-media coalescence module is a rectangular parallelepiped, with a bed thickness of 140-160 mm, and the support plate is made of polytetrafluoroethylene or plexiglass; the enhanced sedimentation module is a woven fiber mesh structure.

[0013] Furthermore, when the treatment object of the coalescence and demulsification device is W / O emulsion, the electret voltage of the electret film is 4-20kV; the electret distance is 20-50mm; the average cross-sectional flow velocity of the multi-media coalescence module is 0.005-0.03m / s, and the coalescence medium filled in the multi-media coalescence module is one or more of hydrophilic anthracite, polytetrafluoroethylene, nylon fiber and glass fiber, and the shape of the coalescence medium is granular, and the particle size is 0.2-3mm.

[0014] Furthermore, when the treatment object of the coalescence and demulsification device is O / W emulsion, the electret voltage of the electret film is 100-1000V; the electret distance is 20-50mm; the average cross-sectional flow velocity of the multi-media coalescence module is 0.02-0.06m / s, and the coalescence medium filled in the multi-media coalescence module is one or more of lipophilic polytetrafluoroethylene, polypropylene, fluorinated polyethylene and fluorocarbon wax, and the shape of the coalescence medium is granular, and the particle size is 0.2-3mm.

[0015] Furthermore, the relative area size relationship among the waterproof dielectric layer, the electret film, the first electrode layer and the first substrate layer is: electret film<first electrode layer<waterproof dielectric layer<first substrate layer.

[0016] Furthermore, the agglomeration and demulsification device also includes an electret switch module located on the outer wall of the shell on the right side of the first base layer of the electret module. The electret switch module is an infrared heater. The electret switch module includes a rectangular shell and a plurality of infrared heating sheets arranged in parallel inside the shell. The temperature control range of the electret switch module is 50-120°C.

[0017] A coalescence and demulsification method based on an electret electrostatic field, using the above-mentioned coalescence and demulsification device based on an electret electrostatic field to separate oil and water from a W / O emulsion or an O / W emulsion, the specific process is as follows:

[0018] The emulsion to be treated enters the coalescence and demulsification device through the liquid inlet, and enters the multi-media coalescence module after passing through the liquid distribution plate and the boiling stop baffle. Under the synergistic effect of the multi-media coalescence module and the electret module, the tiny emulsified droplets are deeply removed; finally, it enters the enhanced sedimentation module, and under the action of the enhanced sedimentation module, the separation of the oil phase and the water phase after demulsification is promoted, and the separated water phase is discharged from the water outlet, and the separated oil phase is discharged from the oil outlet.

[0019] The beneficial effects of the coalescence and demulsification device based on the electret electrostatic field of the present invention are as follows:

[0020] 1. The coalescence and demulsification device based on the electret electrostatic field of the present invention adopts an electret module to replace the electrode assembly of the traditional external active high-voltage power supply to generate the electrostatic field. After the electret module is electret, the electrostatic field can be generated without an external power supply, so that the structure of the demulsification device is simpler and more compact. In addition, the electret is a permanent body and can be used for a long time after being electret once. Compared with the electrode assembly of the traditional external power supply, it greatly reduces energy consumption and has good economic benefits.

[0021] 2. The function of the electret module in the coalescence and demulsification device based on the electret electrostatic field of the present invention is to generate a high-voltage electrostatic field, increase the migration speed of droplets (water droplets in W / O emulsions and oil droplets in O / W emulsions) under the action of the electric field force, promote the coalescence and growth of droplets, and then couple gravity sedimentation to achieve oil-water separation. And the electret module can generate a high voltage of more than 10,000V, which enhances the electric field force on the droplets in the electric field, further enhancing the effect of oil-water separation. Effectively avoid the safety problem of short circuit caused by the overly high voltage of the power supply when using an external power supply.

[0022] 3. The agglomeration and demulsification device based on the electret electrostatic field of the present invention has a simple and compact structure and a simple manufacturing process, and is more suitable for scale production. Moreover, since there is no need to consider power supply requirements, it can be applied to operations under various working conditions, and has greater freedom in the working space. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the structure of a coalescence and demulsification device based on an electret electrostatic field for treating W / O emulsions.

[0024] Figure 2 It is a schematic diagram of the structure of an electret electrostatic field-based coalescence and demulsification device for treating O / W emulsions.

[0025] Figure 3 It is a schematic diagram of the structure of the multi-media coalescing module of the coalescing and demulsifying device.

[0026] Figure 4 It is a schematic diagram of the structure of the electret module of the coalescence and demulsification device.

[0027] Figure 5 It is the front view of the electret module of the coalescence and demulsification device.

[0028] Figure 6 It is a schematic diagram of the structure of the coalescence and demulsification device with the electret switch module added.

[0029] Figure 7 It is a structural schematic diagram of the electret switch module.

[0030] In the figure: 10-shell; 20-liquid distribution tray; 30-boiling stop baffle; 40-multi-media coalescing module; 50-electret module; 60-enhanced sedimentation module;

[0031] 11-liquid inlet; 12-oil outlet; 13-water outlet; 14-feeding port; 15-discharging port;

[0032] 41-coalescing medium; 42-support plate;

[0033] 51-first substrate layer; 52-first electrode layer; 53-electret film; 54-waterproof dielectric layer; 55-second electrode layer; 56-electret switch module; 57-infrared heating sheet; 58-housing;

[0034] 70-backwash inlet; 71-backwash anti-escape component; 72-backwash outlet;

[0035] 80-pressure gauge; 81-differential pressure gauge; 82-interface level gauge. DETAILED DESCRIPTION

[0036] The technical solution of the present invention is clearly and completely described below with specific embodiments in conjunction with the accompanying drawings. It should be understood that the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of the present invention.

[0037] Example 1: A coalescence and demulsification device based on an electret electrostatic field

[0038] like Figure 1 and Figure 2 As shown, the present invention discloses a coalescence and demulsification device based on an electret electrostatic field, the coalescence and demulsification device comprises a shell 10, a liquid distribution tray 20, a boiling stop baffle 30, a multi-media coalescence module 40, an enhanced sedimentation module 60 are sequentially arranged inside the shell 10, and an electret module 50 is arranged on both sides of the multi-media coalescence module 40 and is at the same height as the multi-media coalescence module 40, the liquid distribution tray 20 is externally connected to a liquid inlet 11, and the shell 10 corresponding to the enhanced sedimentation module 60 is provided with an oil outlet 12 and a water outlet 13, wherein:

[0039] Combination Figure 3 As shown, the multi-media coalescing module 40 is uniformly filled with a plurality of coalescing media 41, and a support plate 42 is provided at the bottom of the coalescing media 41; Figure 4 As shown, the electret module 50 includes a waterproof dielectric layer 54, an electret film 53, a first electrode layer 52 and a first substrate layer 51, which are located on one side of the multimedia coalescing module 40 and are tightly attached from the inside to the outside, and a second electrode layer 55 located on the other side of the multimedia coalescing module 40, wherein the first substrate layer 51 and the second electrode layer 55 are tightly attached to the inner wall of the shell 10, and the second electrode layer 55 is arranged opposite to the waterproof dielectric layer 54.

[0040] Furthermore, if Figure 1 As shown, when the treatment object of the coalescing and demulsifying device is W / O emulsion, the interior of the shell 10 of the coalescing and demulsifying device is, from top to bottom, a liquid distribution tray 20, a boiling stop baffle 30, a multi-media coalescing module 40 and an enhanced sedimentation module 60; an oil outlet 12 is provided on the shell 10 on the right side of the enhanced sedimentation module 60, and a water outlet 13 is provided on the shell 10 at the lower part of the enhanced sedimentation module 60; a backwash inlet 70 is provided on the left side of the shell 10 between the multi-media coalescing module 40 and the enhanced sedimentation module 60, and a backwash outlet 72 is provided on the top of the shell 10, and a backwash anti-escape component 71 is provided at the backwash outlet 72, and the backwash anti-escape component 71 is a conventional structure.

[0041] Furthermore, if Figure 2 As shown, when the treatment object of the coalescing and demulsifying device is O / W emulsion, the interior of the shell 10 of the coalescing and demulsifying device is, from bottom to top, a liquid distribution tray 20, a boiling stop baffle 30, a multi-media coalescing module 40 and an enhanced sedimentation module 60, and the shell 10 on the right side of the enhanced sedimentation module 60 is provided with a water outlet 13 and an oil outlet 12 from top to bottom; a backwash inlet 70 is provided on the left side of the shell 10 at the upper part of the enhanced sedimentation module 60, and a backwash outlet 72 is provided at the bottom of the shell 10, and a backwash anti-escape component 71 is provided at the backwash outlet 72.

[0042] Furthermore, a feed port 14 and a discharge port 15 are respectively provided on both sides of the shell 10 at the top of the multi-media coalescing module 40 for replacing the coalescing medium 41 in the multi-media coalescing module 40; when the coalescing and demulsifying device processes W / O emulsion, a pressure gauge 80 is provided on the top of the shell 10, a pressure differential gauge 81 is provided on the top of the multi-media coalescing module 40, and a level gauge 82 is provided at the outlet of the enhanced sedimentation module 60; when the coalescing and demulsifying device processes O / W emulsion, a pressure gauge 80 is provided on the bottom of the shell 10, and a pressure differential gauge 81 is provided on the top of the multi-media coalescing module 40.

[0043] Furthermore, the coalescence and demulsification device is a rectangular parallelepiped, with a length and width of 80-100 mm and a height of 360-400 mm. The material of the waterproof medium layer 54 is PP, PTFE or PMMA, and its thickness is 10 μm-8 mm; the material of the electret film 53 is one or more of PE, PP, PTFE, PMMA, FEP, teflon AF, PFA, PCTEF, ETFE, PI, PET, COC, PVDF and P (VDF-TrFE); the multi-media coalescence module 40 is a rectangular parallelepiped, with a bed thickness of 140-160 mm, and the support plate 42 is made of polytetrafluoroethylene or plexiglass; the enhanced sedimentation module 60 is a woven fiber mesh structure.

[0044] Furthermore, when the treatment object of the coalescence and demulsification device is W / O emulsion, the electret voltage of the electret film 53 is 4-20kV; the electret distance is 20-50mm; the average cross-sectional flow velocity of the multi-media coalescence module 40 is 0.005-0.03m / s, and the coalescence medium 41 filled in the multi-media coalescence module 40 is one or more of hydrophilic anthracite, polytetrafluoroethylene, nylon fiber and glass fiber, and the shape of the coalescence medium 41 is granular, and the particle size is 0.2-3mm.

[0045] Furthermore, when the treatment object of the coalescence and demulsification device is O / W emulsion, the electret voltage of the electret film 53 is 100-1000V; the electret distance is 20-50mm; the average cross-sectional flow velocity of the multi-media coalescence module 40 is 0.02-0.06m / s, and the coalescence medium 41 filled in the multi-media coalescence module 40 is one or more of lipophilic polytetrafluoroethylene, polypropylene, fluorinated polyethylene and fluorocarbon wax, and the shape of the coalescence medium 41 is granular, and the particle size is 0.2-3mm.

[0046] Furthermore, if Figure 5 As shown, the relative area size relationship among the waterproof dielectric layer 54 , the electret film 53 , the first electrode layer 52 and the first substrate layer 51 is: electret film 53 < first electrode layer 52 < waterproof dielectric layer 54 < first substrate layer 51 .

[0047] The inventors found in the test that because the coalescence and demulsification experiment has high requirements on the voltage intensity of the electret, it will limit the electret film material. The untreated electret film 53 will lose charge or lose the ability to generate an electrostatic field during the contact process with the emulsion to be treated. Therefore, a waterproof dielectric layer 54 is added to prevent the direct contact between the emulsion to be treated and the electret film 53.

[0048] Furthermore, if Figure 6 and Figure 7 As shown, the agglomeration and demulsification device also includes an electret switch module 56 located on the outer wall of the shell 10 on the right side of the first substrate layer 51 of the electret module 50. The electret switch module 56 is an infrared heater. The electret switch module 56 includes a rectangular shell 58 and a plurality of infrared heating sheets 57 arranged in parallel inside the shell 58. The temperature control range of the electret switch module 56 is 50-120°C.

[0049] When the infrared heater is turned on, the temperature of the electret film 53 rises, the polarization intensity gradually decreases, and its surface charge gradually decays according to a nearly exponential law, thereby achieving the effect of powering off; when the infrared heater is turned off, the electret film 53 is at room temperature, and at room temperature, the polarization state of the electret film 53 can be maintained for a long time, thereby achieving the effect of powering on, and the electret switch module 56 makes the entire demulsification device safer and more reliable.

[0050] In actual working conditions, the coalescence and demulsification device needs to adjust the type and proportion of the coalescence medium 41 in the multi-media coalescence module 40 according to the type of emulsion to be treated. However, at room temperature, the decay rate of the electret is extremely slow and the time required is too long. The electret switch module 56 can be turned on and off to control the switch of the electret, which effectively improves the operating efficiency of the coalescence and demulsification device and greatly shortens the time required for the electret switch.

[0051] Demulsification method using the above-mentioned coalescence demulsification device based on the electret electrostatic field:

[0052] The emulsion to be treated enters the coalescence and demulsification device through the liquid inlet 11, passes through the liquid distribution plate 20 and the boiling stop baffle 30, and enters the multi-media coalescence module 40. The multi-media coalescence module 40 captures dispersed phase droplets (including oil droplets in O / W emulsion and water droplets in W / O emulsion) and makes the droplets coalesce and grow. The coalescence medium 41 uniformly filled between the waterproof medium layer 54 and the second electrode layer 55 provides a wide range of medium sites for droplet coalescence and induces droplets to coalesce quickly. At the same time, the static electricity generated by the electret module 50 The electric field has an EHD migration effect on the droplets, which can cause the droplets to break away from the continuous phase fluid streamline of the viscous flow and collide with the medium surface, thereby improving the collision efficiency between the tiny droplets and the medium surface. Under the synergistic effect of the multi-media coalescing module 40 and the electret module 50, the tiny emulsified droplets are deeply removed; finally, they enter the enhanced sedimentation module 60, and under the action of the enhanced sedimentation module 60, the oil phase and the water phase after demulsification are separated, and the separated water phase is discharged from the water outlet 13, and the separated oil phase is discharged from the oil outlet 12.

[0053] Demulsification experiments were carried out on W / 0 emulsion and O / W emulsion respectively using the coalescence demulsification device described in Example 1. The materials required in the following examples, such as electret medium layer material, electret film material, coalescence medium, etc., are all commercially available.

[0054] Example 2

[0055] This embodiment is as follows Figure 1 A vertical coalescence and demulsification device based on an electret electrostatic field is shown for treating W / O emulsions. Specifically, the vertical coalescence and demulsification device is in a rectangular shape, with a length and width of 90 mm and a height of 380 mm.

[0056] The waterproof dielectric layer material is PMMA with a thickness of 7 mm; the electret film material is PE, the electret voltage is 10 kV, the electret distance is 35 mm, and the second electrode layer is grounded.

[0057] The average cross-sectional flow velocity in the multi-media coalescing module is 0.01 m / s, and the total thickness of the bed layer of the multi-media coalescing module is 140 mm, wherein it is divided into four bed layers from top to bottom, and each layer is 35 mm thick. The coalescing media are hydrophilic anthracite, polytetrafluoroethylene, nylon fiber and glass fiber from top to bottom, and the above hydrophilic materials are in granular form with a particle size of 0.2-0.3 mm. The material of the support plate is polytetrafluoroethylene; the enhanced sedimentation module is a woven fiber mesh structure.

[0058] The W / O emulsion dispersed phase is distilled water, and the continuous oil phase is a liquid with a density of 842 kg / m 3 , diesel with a viscosity of 3.9mPa, the water content of the emulsion to be treated is 5-10% (v / v), of which the emulsified water accounts for about 1500mg / L, and contains less than 100mg / L of flocculent suspended matter. After the synergistic demulsification of the electret module and the multi-media coalescing module of the demulsification device, the free water content at the oil outlet is 40.5mg / L, the suspended matter content is less than 5mg / L, and the demulsification efficiency is as high as 97.4%.

[0059] Example 3

[0060] The demulsification and separation experiment of the W / O emulsion in this embodiment is basically the same as that in Embodiment 2, except that the electret film material is PP.

[0061] After the synergistic demulsification effect of the electret module and the multi-media coalescing module of the demulsification device, the free water content at the oil outlet is 63 mg / L, and the demulsification efficiency is as high as 95.8%.

[0062] Example 4

[0063] The demulsification and separation experiment of the W / O emulsion in this embodiment is basically the same as that in Embodiment 2, except that the electret film material is PTFE.

[0064] After the synergistic demulsification effect of the electret module and the multi-media coalescing module of the demulsification device, the free water content at the oil outlet is 54 mg / L, and the demulsification efficiency is as high as 96.4%.

[0065] The effects of different electret film materials on the separation performance of W / O emulsions in Examples 2-4 are shown in the following table.

[0066] Table 1 Effect of different electret film materials on the separation performance of W / O emulsion

[0067]

[0068]

[0069] As shown in Table 1, the demulsification efficiency of the coalescence demulsification device of the present invention for W / O emulsions under different electret films is above 95%, showing excellent demulsification ability. Among them, the demulsification efficiency is best when the electret film material is PE.

[0070] Example 5

[0071] This embodiment is as follows Figure 2 A vertical coalescence and demulsification device based on an electret electrostatic field is shown for treating O / W emulsions. Specifically, the vertical coalescence and demulsification device is in a rectangular shape, with a length and width of 90 mm and a height of 380 mm.

[0072] The waterproof dielectric layer material is PMMA with a thickness of 7 mm; the electret film material is PP, the electret voltage is 500 V, the electret distance is 35 mm, and the second electrode layer is grounded.

[0073] The average cross-sectional flow velocity in the multi-media coalescing module is 0.04 m / s, and the total thickness of the bed layer of the multi-media coalescing module is 140 mm, wherein it is divided into four bed layers from top to bottom, and each layer is 35 mm thick. The coalescing media are lipophilic polytetrafluoroethylene, polypropylene, fluorinated polyethylene and fluorocarbon wax from top to bottom, and the above lipophilic materials are in granular form with a particle size of 0.2-0.3 mm. The material of the support plate is polytetrafluoroethylene; the enhanced sedimentation module is a woven fiber mesh structure.

[0074] The O / W emulsion has an oil dispersed phase and a continuous aqueous phase with a density of 1000 kg / m 3 The dispersed oil phase has a density of 842 kg / m 3The oil content of the emulsion to be treated is 5-10% (v / v), of which the emulsified oil accounts for about 1500mg / L and contains less than 150mg / L of flocculent suspended matter. After the synergistic demulsification of the electret module and the multi-media coalescing module of the demulsification device, the oil content at the outlet is 29mg / L, the suspended matter content is less than 5mg / L, and the demulsification efficiency is as high as 98.07%.

[0075] Example 6

[0076] The demulsification and separation experiment of the O / W emulsion in this embodiment is basically the same as that in Embodiment 5, except that the electret film material is PTFE.

[0077] After the synergistic demulsification effect of the electret module and the multi-media coalescing module of the demulsification device, the oil content at the water outlet is 56 mg / L, and the demulsification efficiency is as high as 96.27%.

[0078] Example 7

[0079] The demulsification and separation experiment of the O / W emulsion in this embodiment is basically the same as that in Embodiment 5, except that the electret film material is PMMA.

[0080] After the synergistic demulsification effect of the electret module and the multi-media coalescing module of the demulsification device, the oil content at the water outlet is 63 mg / L, and the demulsification efficiency is as high as 95.80%.

[0081] The effects of different electret film materials on the separation performance of O / W emulsions in Examples 5-7 are shown in the following table.

[0082] Table 2 Effect of different electret film materials on O / W emulsion separation performance

[0083]

[0084] As shown in Table 2, the demulsification efficiency of the coalescence demulsification device of the present invention for O / W emulsions under different electret films is above 95%, showing excellent demulsification ability. Among them, the demulsification efficiency is best when the electret film material is PP.

[0085] Example 8

[0086] Taking the device for enhancing oil dehydration by electric field synergistic medium coalescence in CN112500886A as a comparative example, the energy consumption required for performing demulsification experiments in the same working time between the coalescence and demulsification device based on the electret electrostatic field of the present invention and the device for enhancing oil dehydration by electric field synergistic medium coalescence was compared.

[0087] The device in CN112500886A uses an electrode assembly connected to an external high-voltage power supply to generate an electrostatic field, and the high-voltage power supply must be connected during the demulsification experiment. The present invention uses an electret module to generate an electrostatic field, and the electret time of the electret module is 30-60 minutes, and the electret frequency is 1-2 months / time; in this embodiment, the energy consumption required is calculated based on the electret time of 60 minutes and the electret frequency of 1 month / time.

[0088] Assuming the rated power of the demulsification device is 6kW, it works 22 days a month and 8 hours a day. The energy consumption of the demulsification device in one month is shown in the following table.

[0089] Table 3 Energy consumption of different devices for demulsification experiments in the same working time

[0090]

[0091] It can be seen from Table 3 above that the coalescence and demulsification device based on the electret electrostatic field of the present invention greatly reduces energy consumption compared with the existing electric-dielectric cooperative demulsification device, saves 99.43% of energy consumption per month, and has good economic benefits.

[0092] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention are included in the protection scope of the present invention.

Claims

1. A coalescence and demulsification device based on electret electrostatic field, characterized in that: The coalescence and demulsification device comprises a shell, a liquid distribution tray, a boiling stop baffle, a multi-media coalescence module, an enhanced sedimentation module, and an electret module arranged on both sides of the multi-media coalescence module and at the same height as the multi-media coalescence module in sequence inside the shell, the liquid distribution tray is externally connected to a liquid inlet, and an oil outlet and a water outlet are arranged on the shell corresponding to the enhanced sedimentation module, wherein: The multi-media coalescing module is uniformly filled with several coalescing media, and a support plate is arranged at the bottom of the coalescing media; the electret module comprises a waterproof medium layer, an electret film, a first electrode layer and a first substrate layer, which are located on one side of the multi-media coalescing module and are tightly attached to each other from the inside to the outside, and a second electrode layer located on the other side of the multi-media coalescing module, wherein the first substrate layer and the second electrode layer are tightly attached to the inner wall of the shell, and the second electrode layer is arranged opposite to the waterproof medium layer; The material of the waterproof medium layer is PP, PTFE or PMMA; The material of the electret film is one or more of PE, PP, PTFE, PMMA, FEP, teflon AF, PFA, PCTEF, ETFE, PI, PET, COC, PVDF and P (VDF-TrFE); The coalescence and demulsification device also includes an electret switch module located on the outer wall of the shell on the right side of the first base layer of the electret module. The electret switch module is an infrared heater. The electret switch module includes a rectangular shell and a plurality of infrared heating sheets arranged in parallel inside the shell.

2. The coalescence and demulsification device according to claim 1, characterized in that: When the treatment object of the coalescence and demulsification device is W / O emulsion, the interior of the shell of the coalescence and demulsification device is, from top to bottom, a liquid distribution tray, a boiling stop baffle, a multi-media coalescence module and an enhanced sedimentation module; an oil outlet is provided on the shell on the right side of the enhanced sedimentation module, and a water outlet is provided on the shell at the bottom of the enhanced sedimentation module; a backwash inlet is provided on the left side of the shell between the multi-media coalescence module and the enhanced sedimentation module, a backwash outlet is provided on the top of the shell, and a backwash anti-escape component is provided at the backwash outlet.

3. The coalescence and demulsification device according to claim 1, characterized in that: When the treatment object of the coalescence and demulsification device is O / W emulsion, the interior of the shell of the coalescence and demulsification device is, from bottom to top, a liquid distribution tray, a boiling stop baffle, a multi-media coalescence module and an enhanced sedimentation module, and the shell on the right side of the enhanced sedimentation module is provided with a water outlet and an oil outlet from top to bottom; a backwash inlet is provided on the left side of the shell on the upper part of the enhanced sedimentation module, a backwash outlet is provided at the bottom of the shell, and a backwash anti-escape component is provided at the backwash outlet.

4. The coalescence and demulsification device according to claim 1, characterized in that: A feed port and a discharge port are respectively provided on both sides of the shell at the top of the multi-media coalescing module; when the coalescing and demulsifying device processes W / O emulsion, a pressure gauge is provided on the top of the shell, a differential pressure gauge is provided on the top of the multi-media coalescing module, and a level gauge is provided at the outlet of the enhanced sedimentation module; when the coalescing and demulsifying device processes O / W emulsion, a pressure gauge is provided on the bottom of the shell, and a differential pressure gauge is provided on the top of the multi-media coalescing module.

5. The coalescence and demulsification device according to claim 1, characterized in that: The coalescence and demulsification device is a rectangular parallelepiped, with a length and width of 80-100 mm and a height of 360-400 mm. The thickness of the waterproof medium layer is 10 μm-8 mm. The multi-media coalescence module is a rectangular parallelepiped, with a bed thickness of 140-160 mm. The support plate is made of polytetrafluoroethylene or plexiglass. The enhanced sedimentation module is a woven fiber mesh structure.

6. The coalescence and demulsification device according to claim 1, characterized in that: When the coalescence demulsification device processes W / O emulsion, the electret voltage of the electret film is 4-20 kV; the electret distance is 20-50 mm; The average cross-sectional flow rate of the multi-media coalescing module is 0.005-0.03 m / s. The coalescing medium filled in the multi-media coalescing module is one or more of hydrophilic anthracite, polytetrafluoroethylene, nylon fiber and glass fiber. The coalescing medium is in the shape of particles with a particle size of 0.2-3 mm.

7. The coalescence and demulsification device according to claim 1, characterized in that: When the processing object of the coalescence demulsification device is an O / W emulsion, the electret voltage of the electret film is 100-1000V; the electret distance is 20-50mm; The average cross-sectional flow rate of the multi-media coalescing module is 0.02-0.06 m / s. The coalescing medium filled in the multi-media coalescing module is one or more of lipophilic polytetrafluoroethylene, polypropylene, fluorinated polyethylene and fluorocarbon wax. The coalescing medium is in the shape of particles with a particle size of 0.2-3 mm.

8. The coalescence and demulsification device according to claim 1, characterized in that: The relative area size relationship of the waterproof dielectric layer, the electret film, the first electrode layer and the first substrate layer is: electret film<first electrode layer<waterproof dielectric layer<first substrate layer.

9. The coalescence and demulsification device according to claim 1, characterized in that: The temperature control range of the electret switch module is 50-120°C.

10. A method for coalescence and demulsification based on electret electrostatic field, characterized in that: The coalescence and demulsification device based on the electret electrostatic field according to any one of claims 1 to 9 is used to separate oil and water from W / O emulsion or O / W emulsion, and the specific process is as follows: The emulsion to be treated enters the coalescence and demulsification device through the liquid inlet, and enters the multi-media coalescence module after passing through the liquid distribution plate and the boiling stop baffle. Under the synergistic effect of the multi-media coalescence module and the electret module, the tiny emulsified droplets are deeply removed; finally, it enters the enhanced sedimentation module, and under the action of the enhanced sedimentation module, the separation of the oil phase and the water phase after demulsification is promoted, and the separated water phase is discharged from the water outlet, and the separated oil phase is discharged from the oil outlet.

Images