Ultrasonic and electric field coupling demulsification method, module and separation device

Abstract

The invention discloses an ultrasonic and electric field coupled demulsification method, module and separation device, and relates to the technical field of separation methods for oil exploitation, the method comprises the following steps: simultaneously applying an ultrasonic field and an electric field to a to-be-treated emulsion in the same area; carrying out synergistic demulsification on the emulsion by utilizing an ultrasonic cavitation effect and an electric field polarization effect, or carrying out synergistic demulsification on the emulsion by utilizing an ultrasonic mechanical effect and the electric field polarization effect; and carrying out oil-water separation on the emulsion subjected to demulsification treatment. Through the synergistic effect of the ultrasonic cavitation effect, the mechanical effect and the electric field polarization effect, dispersed water drops in oil are promoted to be quickly coalesced, and the demulsification efficiency of emulsion is improved; meanwhile, according to the device, an ultrasonic and electric field coupling demulsification module can be arranged according to the section characteristics of the separation device, and ultrasonic parameters and electric field parameters can be adjusted according to the emulsion characteristics of different section areas, so that the demulsification effect is optimized.

Description

Technical Field

[0001] The invention relates to the technical field of separation methods for petroleum exploitation, and in particular to an ultrasound and electric field coupling demulsification method, a module and a separation device. Background Art

[0002] In the process of oil extraction, oil displacement agents such as surfactants and polymers are usually added to enhance the oil stripping and migration capabilities of the displacement fluid, thereby improving the recovery rate of crude oil. However, while these oil displacement agents improve the recovery rate, they also significantly enhance the emulsification stability of the produced fluid, making oil-water separation more difficult. Existing demulsification methods mainly include thermochemical demulsification, electrical demulsification and ultrasonic demulsification. Among them, the electrical demulsification method mainly utilizes the polarization effect of the electric field. The polarization effect induces the water droplets to be induced and charged, enhances the collision and coalescence of the water droplets, and accelerates the demulsification process. The ultrasonic demulsification method mainly utilizes the cavitation effect and thermal effect of ultrasound. The cavitation effect causes oscillating microbubbles to be generated at the interface of the water droplets, prompting the water droplets to oscillate cooperatively and weakening the strength of the interfacial film. The thermal effect can reduce the viscosity of the emulsion, reduce the resistance to the migration of water droplets, and facilitate the collision and coalescence of water droplets.

[0003] However, existing demulsification technologies such as thermochemical demulsification, electrostatic demulsification and ultrasonic demulsification based on a single demulsification principle all have certain limitations, and it is difficult to achieve efficient treatment of complex produced fluids. In addition, there are also devices that combine electrostatic technology with ultrasonic technology to achieve demulsification, such as Chinese patent CN115838605A discloses an array-type ultrasonic demulsification electric desalination and dehydration device, which enhances the dehydration effect by arranging an ultrasonic transducer array under the electrode plate. However, the device is essentially a series connection form of ultrasonic demulsification and electrostatic demulsification, which can improve the demulsification efficiency to a certain extent, but it is still difficult to meet the needs of efficient oil-water separation. Therefore, the single effect of ultrasonic demulsification and electrostatic demulsification, as well as the sequential effect of the two, are difficult to achieve efficient demulsification of complex produced fluids. Summary of the invention

[0004] In view of the problems existing in the prior art, the present invention provides an ultrasonic and electric field coupled demulsification method, module and separation device. The method promotes the rapid coalescence of dispersed water droplets in the oil through the synergistic effect of ultrasonic cavitation effect, mechanical effect and electric field polarization effect, thereby improving the demulsification efficiency of the emulsion. At the same time, the device of the present invention can arrange the ultrasonic and electric field coupled demulsification module according to the cross-sectional characteristics of the separation device, and can adjust the ultrasonic parameters and electric field parameters according to the emulsion characteristics of different cross-sectional areas to optimize the demulsification effect.

[0005] The technical solution of the present invention is as follows:

[0006] In a first aspect of the present invention, there is provided a method for demulsification by coupling ultrasound and electric field, comprising the following steps:

[0007] Step 1: Apply an ultrasonic field and an electric field to the emulsion to be treated simultaneously in the same area;

[0008] Step 2: Adjust the ultrasonic parameters to the range that can generate a steady-state cavitation effect in the emulsion, and at the same time adjust the electric field parameters to the range that can promote effective electrocoagulation of water droplets in the emulsion, and use the ultrasonic cavitation effect and the electric field polarization effect to carry out cooperative demulsification of the emulsion;

[0009] Or, adjust the ultrasonic parameters to the range that can form a standing wave field in the emulsion, and at the same time adjust the electric field parameters to the range that can promote effective electrocoagulation of water droplets in the emulsion, and use the ultrasonic mechanical effect and the electric field polarization effect to carry out cooperative demulsification of the emulsion;

[0010] Step 3: Separate the oil and water from the emulsion demulsified in Step 2.

[0011] In some embodiments of the present invention, the ultrasonic field and the electric field are vertically arranged.

[0012] In a second aspect of the present invention, there is provided an ultrasonic and electric field coupling demulsification module, including at least one ultrasonic and electric field coupling demulsification unit, and the unit includes electrode plates, transducers, acoustic matching plates, acoustic reflection plates and protective shells; the electrode plates, acoustic matching plates and acoustic reflection plates enclose a flow channel, the electrode plates are arranged in pairs opposite to each other, the acoustic matching plates and the acoustic reflection plates are arranged opposite to each other, the transducers are located outside the flow channel and are installed on the acoustic matching plates, protective shells are arranged outside the transducers, the electrode plates are used to apply an electric field to the emulsion in the flow channel, and the transducers are used to apply an ultrasonic field to the emulsion in the flow channel, and the electric field and the ultrasonic field are used to carry out cooperative demulsification of the emulsion in the flow channel.

[0013] In some embodiments of the present invention, the electrode plates are arranged vertically relative to each other, and the acoustic matching plates and the acoustic reflection plates are arranged horizontally relative to each other.

[0014] In some embodiments of the present invention, the electrode plates are arranged horizontally relative to each other, and the acoustic matching plates and the acoustic reflection plates are arranged vertically relative to each other.

[0015] In some embodiments of the present invention, when using the ultrasonic mechanical effect, the distance between the acoustic matching plate and the acoustic reflection plate is an integer multiple of half the wavelength of the ultrasonic wave in the emulsion.

[0016] In some embodiments of the present invention, at least one transducer is installed on the acoustic matching plate, and the transducers can be protected by sharing the protective shell.

[0017] In some embodiments of the present invention, when multiple ultrasonic and electric field coupling demulsification units are provided, adjacent ultrasonic and electric field coupling demulsification units can share the electrode plates, and the electrode plates are arranged in an alternating pattern of high-voltage electrode plates and low-voltage electrode plates.

[0018] In the third aspect of the present invention, a separation device is provided. The ultrasonic and electric field coupled demulsification module is arranged in the emulsion layer region of the separation device according to the cross-sectional characteristics of the separation device, and the flow direction in the ultrasonic and electric field coupled demulsification module is consistent with the flow direction of the emulsion in the separation device.

[0019] In some embodiments of the present invention, the ultrasonic and electric field coupled demulsification module adjusts the ultrasonic parameters and electric field parameters according to the emulsion characteristics in different cross-sectional regions of the separation device.

[0020] One or more technical solutions of the present invention have the following beneficial effects:

[0021] (1) The ultrasonic and electric field coupled demulsification method provided by the present invention proposes to use the ultrasonic cavitation effect and the electric field polarization effect for synergistic demulsification. During the synergistic demulsification process, both the cavitation effect and the polarization effect can reduce the interfacial film strength between water droplets. The synergistic effect of the two can further reduce the interfacial film strength of water droplets, thus facilitating the coalescence of water droplets; or, use the ultrasonic mechanical effect and the electric field polarization effect for synergistic demulsification. During the synergistic demulsification process, the ultrasonic mechanical effect can promote the aggregation of dispersed water droplets to form water droplet strips, shortening the distance between water droplets, and the intensity of the electric field polarization effect is inversely proportional to the distance between water droplets. That is, the ultrasonic mechanical effect on the aggregation of dispersed water droplets strengthens the polarization effect of the electric field. The synergistic effect of the two can achieve the efficient coalescence of dispersed water droplet groups.

[0022] Through the above demulsification method, the ultrasonic field and the electric field can achieve better coupling. Compared with the single action of the ultrasonic demulsification and electrostatic demulsification methods, and the sequential action of the two, this method comprehensively utilizes the cavitation effect, mechanical effect of ultrasound and the polarization effect of the electric field, and can greatly improve the demulsification efficiency of the emulsion.

[0023] (2) Compared with the thermal chemical demulsification method, the ultrasonic and electric field coupled demulsification method of the present invention has significant advantages in terms of energy consumption and usage cost. The ultrasonic and electric field coupled demulsification greatly reduces the demulsification temperature and the usage amount of chemical reagents, thereby reducing the overall energy consumption and operation cost, and has a wide application prospect in the petrochemical field.

[0024] (3) The ultrasonic and electric field coupled demulsification module proposed by the present invention can be arranged according to the cross-sectional characteristics of the separation device. This modular design not only improves the flexibility and adaptability of the device, but also facilitates the installation and maintenance of the equipment; the ultrasonic parameters and electric field parameters of different modules can be independently regulated according to the emulsion characteristics of the location to optimize the demulsification effect. Description of the Drawings

[0025] Figure 1 It is a schematic diagram of the synergistic demulsification mechanism of the ultrasonic cavitation effect, ultrasonic mechanical effect and electric field polarization effect in the ultrasonic and electric field coupled demulsification method of Embodiment 1 of the present invention;

[0026] Figure 2 Schematic diagram of the ultrasonic and electric field coupling demulsification unit structure in Embodiment 2 of the present invention Figure 1 ;

[0027] Figure 3 Schematic diagram of the ultrasonic and electric field coupling demulsification unit structure in Embodiment 2 of the present invention Figure 2 ;

[0028] Figure 4 is Figure 2 Schematic diagram of the ultrasonic and electric field coupling demulsification module structure corresponding to the ultrasonic and electric field coupling demulsification unit shown;

[0029] Figure 5 is Figure 3 Schematic diagram of the ultrasonic and electric field coupling demulsification module structure corresponding to the ultrasonic and electric field coupling demulsification unit shown;

[0030] Figure 6 Schematic diagram of the separation device structure in Embodiment 3 of the present invention;

[0031] Figure 7 is Figure 4 after the ultrasonic and electric field coupling demulsification module in Figure 6 is installed inside the separation device shown; A - A sectional view;

[0032] Figure 8 is Figure 5 after the ultrasonic and electric field coupling demulsification module in Figure 6 is installed inside the separation device shown; A - A sectional view.

[0033] In the figure, 1. electrode plate; 2. transducer; 3. acoustic matching plate; 4. acoustic reflector; 5. protective shell; 6. separator inlet; 7. rectifying plate; 8. separator cylinder; 9. ultrasonic and electric field coupling demulsification module; 10. gas outlet; 11. weir plate; 12. water outlet; 13. oil outlet; 14. inlet member; 15. mist eliminator; 16. water layer; 17. emulsion layer; 18. oil layer. Specific embodiments

[0034] The present invention will be further described below in conjunction with the drawings and embodiments.

[0035] Embodiment 1

[0036] The technical concept of the present invention is as follows:

[0037] The electric field demulsification technology is widely used in oil fields because of its simplicity and high efficiency. However, it is difficult to achieve efficient demulsification of complex produced fluids. The demulsification mechanism of ultrasonic demulsification technology is relatively complex, and the demulsification effect is difficult to control. The existing ultrasonic demulsification technology mainly adopts the demulsification principle of ultrasonic cavitation effect. The inventor noticed that ultrasonic not only has cavitation effect, but also has mechanical effect caused by ultrasonic standing wave field. And the combination of these two effects and electric field polarization effect can achieve better demulsification effect. The idea of this invention is proposed based on the research of ultrasonic and electric field demulsification mechanisms. By limiting the ultrasonic parameters and electric field parameters, ultrasonic and electric field coupled demulsification is realized.

[0038] For this reason, in a typical embodiment of the present invention, an ultrasonic and electric field coupled demulsification method is provided, including the following steps:

[0039] Step 1: Apply an ultrasonic field and an electric field to the emulsion to be treated in the same area simultaneously;

[0040] Step 2: Adjust the ultrasonic parameters to the range that can generate steady-state cavitation effect in the emulsion, and at the same time adjust the electric field parameters to the range that can promote effective electrocoagulation of water droplets in the emulsion, and use the ultrasonic cavitation effect and electric field polarization effect to carry out synergistic demulsification on the emulsion;

[0041] Or, adjust the ultrasonic parameters to the range that can form a standing wave field in the emulsion, and at the same time adjust the electric field parameters to the range that can promote effective electrocoagulation of water droplets in the emulsion, and use the ultrasonic mechanical effect and electric field polarization effect to carry out synergistic demulsification on the emulsion;

[0042] Step 3: Separate the oil and water of the emulsion demulsified in Step 2.

[0043] When using the ultrasonic cavitation effect and electric field polarization effect to carry out synergistic demulsification on the emulsion, the ultrasonic steady-state cavitation effect generates periodic oscillating bubbles to promote the oscillation of water droplets, weaken the stability of the interfacial film, and at the same time the oscillation of water droplets accelerates the coalescence of adjacent water droplets; the electric field polarization effect enhances the oscillation of water droplets, further reduces the strength of the interfacial film, and promotes the directional migration and coalescence of water droplets through electrophoresis and dielectrophoresis effects. The two synergistic demulsification significantly improves the coalescence efficiency of dispersed water droplets, thus accelerating the demulsification process.

[0044] When using the ultrasonic mechanical effect and electric field polarization effect to carry out synergistic demulsification on the emulsion, under the action of the standing wave field, the ultrasonic mechanical effect drives the dispersed water droplets to migrate to the pressure node region, forming a strip-like water droplet distribution, shortening the distance between water droplets, and promoting the coalescence of water droplets; the electric field polarization effect enhances the oscillation of water droplets, reduces the strength of the interfacial film, and promotes the directional migration and coalescence of water droplets through electrophoresis and dielectrophoresis effects with stronger action at short distances; the two synergistic demulsification effectively improves the coalescence efficiency of dispersed water droplets, thus accelerating the demulsification process.

[0045] In this embodiment, the ultrasonic field and the electrostatic field are perpendicularly arranged. Specifically, when the ultrasonic cavitation effect and the electric field polarization effect are used for cooperative demulsification of the emulsion, the ultrasonic field and the electrostatic field can be arranged arbitrarily according to needs; when the ultrasonic mechanical effect and the electric field polarization effect are used for cooperative demulsification of the emulsion, it is only necessary to ensure that the ultrasonic field and the electrostatic field are not parallel. However, when the ultrasonic field and the electrostatic field are perpendicularly arranged, the demulsification effect reaches the optimum.

[0046] In this embodiment, the range where the steady-state cavitation effect occurs in the emulsion, the range where effective electrocoagulation of water droplets occurs in the emulsion, and the range where a standing wave field is formed in the emulsion are all obtained through experiments.

[0047] Among them, the cavitation effect of ultrasonic waves generally occurs at a relatively low ultrasonic frequency. Under the condition that parameters such as the ultrasonic frequency remain unchanged, as the ultrasonic intensity (sound intensity) increases, the change of cavitation bubbles gradually becomes violent. When the sound intensity parameter exceeds the transient cavitation threshold, the cavitation bubbles will burst, causing high temperature and pressure, shock waves and microjets. This effect will cause the secondary fragmentation of water droplets, thus aggravating emulsification. Therefore, the sound intensity needs to be lower than the transient cavitation threshold. However, when the sound intensity is too low, no cavitation effect will be generated. Therefore, there is a steady-state cavitation range, and this numerical range is related to the physical properties of the emulsion and can be obtained through experimental measurement.

[0048] Generally, the greater the electric field strength, the stronger the electrophoresis and dielectrophoresis effects, and the faster the water droplets migrate and approach each other, resulting in a higher coalescence efficiency. However, in fact, after the water droplets collide, charge exchange will occur, causing the charge that originally drove the water droplets to attract to turn into pulling the water droplets away. This effect will exceed the capillary force between the water droplets after the electric field strength reaches a certain threshold, resulting in non-coalescence of the water droplets. At a particularly high field strength, a single water droplet will be broken by its own opposite charges, resulting in smaller water droplets and aggravating emulsification. When the electric field strength is too low, the migration speed of the water droplets is slow and the electrocoagulation efficiency is very low. Therefore, there is an effective electrocoagulation range, and this numerical range is related to the physical properties of the emulsion and can be obtained through experimental measurement.

[0049] When the distance between the ultrasonic incident end and the reflection end is an integer multiple of half the wavelength, an ultrasonic standing wave field will be formed. In the standing wave field, the ultrasonic mechanical effect drives the dispersed water droplets to migrate towards the pressure node region, forming water droplet bands. Generally, the ultrasonic standing wave field is established at a relatively high ultrasonic frequency. When the ultrasonic frequency is too low, cavitation will occur, interfering with the migration of water droplets. When the ultrasonic frequency is too high, the wavelength will be too long to exceed the accommodation range of the experimental equipment. The migration efficiency of water droplets increases with the increase of the sound intensity. However, when the sound intensity is too high, a streaming phenomenon will occur, which will then disturb and damage the water droplet bands. Therefore, there is also an efficient action range for the ultrasonic mechanical effect, and this numerical range is related to the physical properties of the emulsion and can be obtained through experimental measurement.

[0050] The demulsification principle of coupling ultrasound and electric field in this embodiment is compared with the existing demulsification principles of applying only electric field or only ultrasound. As Figure 1 shown, (a), (d), (g), and (j) are for applying only electric field, (b), (e), (h), and (k) are for applying only ultrasound field, and (c), (f), (i), and (l) are for the synergistic action of ultrasound field and electric field; (c) and (f) are for the synergistic action of ultrasonic cavitation effect and electric field polarization effect; (i) and (l) are for the synergistic action of ultrasonic mechanical effect and electric field polarization effect; (c) and (i) are for the arrangement form where the electrode plates are vertically arranged and the acoustic matching layer and acoustic reflector are horizontally arranged, that is, the electric field direction is perpendicular to the gravity field direction and the ultrasound field direction is parallel to the gravity field direction. This embodiment's implementation mode 1 adopts this arrangement form; (f) and (l) are for the arrangement form where the electrode plates are horizontally arranged and the acoustic matching layer and acoustic reflector are vertically arranged, that is, the electric field direction is parallel to the gravity field direction and the ultrasound field direction is perpendicular to the gravity field direction. This embodiment's implementation mode 2 adopts this arrangement form.

[0051] The specific analysis is as follows:

[0052] As Figure 1 shown in (a), (d), (g), and (j) in, when only applying an electric field, the polarization effect induces the water droplets to be inductively charged, thereby promoting the oscillation and migration of the water droplets. The high-frequency oscillation can weaken the strength of the water droplet interfacial film, and the electrophoresis and dielectrophoresis effects promote the directional migration of the water droplets, enhance the collision and coalescence of the water droplets, and accelerate the demulsification process.

[0053] As Figure 1 shown in (b) and (e) in, when only applying an ultrasound field and controlling the ultrasound parameters within the steady-state cavitation range, the cavitation effect can generate periodically oscillating microbubbles at the water droplet interface, promoting the cooperative oscillation of the water droplets, weakening the oil-water interfacial film, and at the same time the oscillation of the water droplets can also promote the coalescence of adjacent water droplets.

[0054] As Figure 1 shown in (h) and (k) in, when only applying an ultrasound field and controlling the ultrasound parameters to form a standing wave field, the ultrasonic mechanical effect drives the dispersed water droplets to migrate towards the pressure node region, forming a strip-shaped water droplet distribution and promoting the coalescence of the water droplets, as shown by the dark regions in (h) and (k).

[0055] As Figure 1As shown in (c) and (f), when an ultrasonic field and an electric field are applied simultaneously and the ultrasonic parameters are controlled within the range of stable cavitation, the stable cavitation effect of ultrasound generates periodic oscillating bubbles to promote the oscillation of water droplets, weakening the stability of the interfacial film. At the same time, the oscillation of water droplets accelerates the coalescence of adjacent water droplets; the electric field polarization effect promotes the oscillation of water droplets, further reducing the strength of the interfacial film, and promoting the directional migration and coalescence of water droplets through electrophoresis and dielectrophoresis effects. The synergistic effect of the two can effectively improve the coalescence efficiency of water droplets, thus accelerating the demulsification process.

[0056] As Figure 1 As shown in (i) and (l), when an ultrasonic field and an electric field are applied simultaneously and the ultrasonic parameters are controlled to form a standing wave field, the ultrasonic mechanical effect drives the dispersed water droplets to migrate towards the pressure node region, forming a strip-shaped water droplet distribution, shortening the water droplet spacing, and promoting the coalescence of water droplets; the electric field polarization effect promotes the oscillation of water droplets, reducing the strength of the interfacial film, and promoting the directional migration and coalescence of water droplets through electrophoresis and dielectrophoresis effects with stronger effects at short distances. The synergistic effect of the two can significantly improve the coalescence efficiency of dispersed water droplets, thus accelerating the demulsification process.

[0057] Embodiment 1

[0058] Under the condition of 20 °C, an oil-in-water emulsion was simulated and prepared using Triton X-100 reagent, deionized water and dimethyl silicone oil. The addition concentration of Triton X-100 reagent was 500 ppm, and an IKA-T18 type disperser was used to stir at a speed of 15000 rpm for 10 min to prepare the emulsion.

[0059] In the oil-in-water emulsion with a water content of 10% prepared under the above conditions, the average particle size of the dispersed phase remained at about 15 μm. A gravity sedimentation experiment was carried out on this emulsion. The gravity sedimentation efficiency at 15 min was 0%, and the gravity sedimentation efficiency at 30 min was only 9%, indicating that the oil-in-water emulsion obtained by this configuration method has a certain stability.

[0060] For the above oil-in-water emulsion, when only the electric field polarization effect was used for demulsification, at the optimal electric field parameters obtained in the experiment (electric field waveform: bipolar square wave, electric field frequency: 3 kHz, electric field intensity: 70 kV / m), the demulsification efficiency at 3 min was 55.32%;

[0061] When only the ultrasonic cavitation effect was used for demulsification, at the optimal ultrasonic parameters obtained in the experiment (ultrasonic frequency: 27.97 kHz, ultrasonic intensity: 0.4 W / cm 2 ), the demulsification efficiency at 3 min was 32.50%;

[0062] When only the ultrasonic mechanical effect was used for demulsification, at the optimal ultrasonic parameters obtained in the experiment (ultrasonic frequency: 126.18 kHz, ultrasonic intensity: 0.6 W / cm 2)Under these conditions, the demulsification efficiency at 3 min is 46.00%;

[0063] When using the synergistic demulsification of ultrasonic cavitation effect and electric field polarization effect, under the optimal ultrasonic parameters and electric field parameters obtained from the experiment (electric field waveform: bipolar square wave, electric field frequency: 3 kHz, electric field intensity: 70 kV / m, ultrasonic frequency: 27.97 kHz, ultrasonic intensity: 0.3 W / cm 2 )Under these conditions, the demulsification efficiency at 3 min is 68.80%;

[0064] When using the synergistic demulsification of ultrasonic mechanical effect and electric field polarization effect, under the optimal ultrasonic parameters and electric field parameters obtained from the experiment (electric field waveform: bipolar square wave, electric field frequency: 3 kHz, electric field intensity: 70 kV / m, ultrasonic frequency: 126.18 kHz, ultrasonic intensity: 0.6 W / cm 2 )Under these conditions, the demulsification efficiency at 3 min is 76.50%.

[0065] Through comparative analysis, the method provided in this embodiment has a better demulsification effect.

[0066] Embodiment 2

[0067] For the above oil-in-water emulsion, when only using the electric field polarization effect for demulsification, under the optimal electric field parameters obtained from the experiment (electric field waveform: bipolar square wave, electric field frequency: 3 kHz, electric field intensity: 70 kV / m), the demulsification efficiency at 3 min is 55.32%;

[0068] When only using the ultrasonic cavitation effect for demulsification, under the optimal ultrasonic parameters obtained from the experiment (ultrasonic frequency: 27.97 kHz, ultrasonic intensity: 0.5 W / cm 2 )Under these conditions, the demulsification efficiency at 3 min is 33.00%;

[0069] When only using the ultrasonic mechanical effect for demulsification, under the optimal ultrasonic parameters obtained from the experiment (ultrasonic frequency: 126.18 kHz, ultrasonic intensity: 0.6 W / cm 2 )Under these conditions, the demulsification efficiency at 3 min is 42.67%;

[0070] When using the synergistic demulsification of ultrasonic cavitation effect and electric field polarization effect, under the optimal ultrasonic parameters and electric field parameters obtained from the experiment (electric field waveform: bipolar square wave, electric field frequency: 3 kHz, electric field intensity: 70 kV / m, ultrasonic frequency: 27.97 kHz, ultrasonic intensity: 0.4 W / cm 2 )Under these conditions, the demulsification efficiency at 3 min is 70.00%;

[0071] When using the synergistic demulsification of ultrasonic mechanical effect and electric field polarization effect, under the optimal ultrasonic parameters and electric field parameters obtained from the experiment (electric field waveform: bipolar square wave, electric field frequency: 3 kHz, electric field intensity: 70 kV / m, ultrasonic frequency: 126.18 kHz, ultrasonic intensity: 0.6 W / cm 2 ), the demulsification efficiency is 76.87% at 3 min.

[0072] Through comparative analysis, the method provided in this embodiment has a better demulsification effect.

[0073] Embodiment 2

[0074] In a typical implementation manner of the present invention, an ultrasonic and electric field coupling demulsification module is provided. As Figures 2 to 5 shown, it includes at least one ultrasonic and electric field coupling demulsification unit. The unit includes an electrode plate 1, a transducer 2, an acoustic matching plate 3, an acoustic reflector 4, and a protective shell 5; the electrode plate 1, the acoustic matching plate 3, and the acoustic reflector 4 enclose a flow channel. The electrode plates 1 are arranged in pairs opposite to each other, the acoustic matching plate 3 and the acoustic reflector 4 are arranged opposite to each other, the transducer 2 is located outside the flow channel and installed on the acoustic matching plate 3, a protective shell 5 is arranged outside the transducer 2, the electrode plate 1 is used to apply an electric field to the emulsion in the flow channel, and the transducer 2 is used to apply an ultrasonic field to the emulsion in the flow channel, and the electric field and the ultrasonic field are used to carry out synergistic demulsification on the emulsion in the flow channel.

[0075] In this embodiment, the acoustic reflector 4 is used to reflect ultrasonic waves to assist in generating an ultrasonic standing wave field; the acoustic matching plate 3 is used to optimize the energy transmission of the ultrasonic waves of the transducer 2, reduce the acoustic impedance difference between the transducer 2 and the processing medium, thereby reducing the propagation energy loss and improving the ultrasonic energy transmission efficiency. The protective shell 5 is arranged around the transducer 2 to prevent the emulsion from entering the transducer area.

[0076] Optionally, the electrode plates 1 are arranged vertically relative to each other, and the acoustic matching plate 3 and the acoustic reflector 4 are arranged horizontally relative to each other. As Figure 2 shown.

[0077] Optionally, the electrode plates 1 are arranged horizontally relative to each other, and the acoustic matching plate 3 and the acoustic reflector 4 are arranged vertically relative to each other. As Figure 3 shown.

[0078] Optionally, when using the ultrasonic mechanical effect, the distance between the acoustic matching plate 3 and the acoustic reflector 4 is an integer multiple of half the wavelength of the ultrasonic wave in the emulsion.

[0079] In this embodiment, one or more transducers 2 can be installed on the acoustic matching plate 3, and the transducers 2 can be protected by sharing the protective shell 5. As Figure 2 and Figure 3 shown.

[0080] In this embodiment, adjacent ultrasonic and electric field coupling demulsification units in the ultrasonic and electric field coupling demulsification module can share the electrode plate 1, and the electrode plate 1 is arranged with high-voltage electrode plates and low-voltage electrode plates staggered, as Figure 4 and Figure 5 shown.

[0081] Embodiment 3

[0082] In a typical embodiment of the present invention, a separation device is provided, including the ultrasonic and electric field coupling demulsification module described in Embodiment 2. The ultrasonic and electric field coupling demulsification module is arranged in the emulsion layer area of the separation device according to the cross-sectional characteristics of the separation device, and the flow direction in the ultrasonic and electric field coupling demulsification module is the same as the flow direction of the emulsion in the separation device.

[0083] Optionally, the ultrasonic and electric field coupling demulsification module adjusts the ultrasonic parameters and electric field parameters according to the emulsion characteristics in different cross-sectional areas of the separation device.

[0084] As Figures 6 to 8 shown, the separation device includes a separator cylinder body 8. An ultrasonic and electric field coupling demulsification module 9 is arranged in the separator cylinder body 8, and the ultrasonic and electric field coupling demulsification module 9 is installed at the position of the emulsion layer 17 behind the rectifying plate 7 in the separator cylinder body 8; the separator cylinder body 8 is horizontal, and a rectifying plate 7 and a weir plate 11 are arranged in the separator cylinder body 8. The rectifying plate 7 and the weir plate 11 are arranged in parallel and separated by a set distance. The ultrasonic and electric field coupling demulsification module 9 is arranged between the rectifying plate 7 and the weir plate 11 and close to the rectifying plate 7.

[0085] Further, a separator inlet 6, a gas outlet 10, a water outlet 12 and an oil outlet 13 are arranged on the separator cylinder body 8. Among them, the separator inlet 6 is located at one end of the separator cylinder body 8, the gas outlet 10 is located at the top of the other end of the separator cylinder body 8, the oil outlet 13 is located at the bottom of the other end of the separator cylinder body 8, and the water outlet 12 is located at the bottom position of the separator cylinder body 8 between the rectifying plate 7 and the weir plate 11 and close to the weir plate 11.

[0086] Further, an inlet member 14 is arranged at the separator inlet 6, and a mist eliminator 15 is arranged at the gas outlet 10.

[0087] The working principle of the separation device equipped with the ultrasonic and electric field coupling demulsification module is as follows:

[0088] The produced medium in the oilfield enters the interior of the separation device through the separator inlet 6 via the inlet component 14. Most of the gas is separated at the inlet component 14, and after demisting by the mist eliminator 15, it is discharged through the gas outlet 10. At the same time, the oil-water emulsion drops to the liquid layer at the inlet component 14, forms a stable flow after being rectified by the rectifying plate 7, enters the ultrasonic and electric field coupling demulsification module 9, and after demulsification by this module, the emulsion layer 17 is gradually separated into an oil layer 18 and a water layer 16. The separated oil layer 18 bypasses the weir plate 11 and enters the oil chamber, and is discharged from the oil outlet 13; the separated water layer 16 is discharged through the water outlet 12.

[0089] Furthermore, by adjusting the ultrasonic parameters and electric field parameters, the ultrasonic cavitation effect and the electric field polarization effect are used to demulsify the emulsion synergistically. Specifically, the ultrasonic and electric field coupling demulsification module sets the ultrasonic parameters so that the ultrasonic parameters are within the range of the stable cavitation effect, avoiding the fragmentation of water droplets caused by transient cavitation; by setting the electric field parameters, the electric field parameters are adjusted to be within the effective electrocoalescence range of water droplets in the emulsion, preventing the non-coalescence and fragmentation of water droplets caused by an overly strong electric field.

[0090] The periodic oscillating bubbles generated by the ultrasonic stable cavitation effect prompt the oscillation of water droplets, weaken the stability of the interfacial film. At the same time, the oscillation of water droplets accelerates the coalescence of adjacent water droplets; the electric field polarization effect prompts the oscillation of water droplets, further reduces the strength of the interfacial film, and promotes the directional migration and coalescence of water droplets through electrophoresis and dielectrophoresis effects. The synergistic demulsification of the two can effectively improve the coalescence efficiency of water droplets, thus accelerating the demulsification process.

[0091] Optionally, by adjusting the ultrasonic parameters and electric field parameters, the ultrasonic mechanical effect and the electric field polarization effect are used to demulsify the emulsion synergistically. Specifically, the ultrasonic and electric field coupling demulsification module sets the ultrasonic parameters so that the ultrasonic parameters can form a standing wave field; by setting the electric field parameters, the electric field parameters are adjusted to be within the effective electrocoalescence range of water droplets in the emulsion, preventing the non-coalescence and fragmentation of water droplets caused by an overly strong electric field.

[0092] Under the action of the standing wave field, the ultrasonic mechanical effect drives the dispersed water droplets to migrate towards the pressure node region, forming a strip-shaped water droplet distribution, shortening the distance between water droplets, and promoting the coalescence of water droplets; the electric field polarization effect prompts the oscillation of water droplets, reduces the strength of the interfacial film, and promotes the directional migration and coalescence of water droplets through stronger electrophoresis and dielectrophoresis effects at short distances. The synergistic demulsification of the two can significantly improve the coalescence efficiency of dispersed water droplets, thus accelerating the demulsification process.

[0093] Furthermore, the rectifying plate 7 in the separator and the ultrasonic and electric field coupling demulsification module 9 serve as a sedimentation section. The purpose is to allow the emulsion to flow horizontally and then achieve a certain separation under the action of gravity, and then enter the ultrasonic and electric field coupling demulsification module 9. At this time, the water content of the emulsion is different in the vertical height. More specifically, the droplet size and density in the emulsion are different at different heights. The number of water droplets and the droplet size are smaller as the height increases. Therefore, modules at different heights achieve efficient demulsification by applying different electric field parameters and ultrasonic field parameters. At the same time, it also avoids the situation that excessive local parameters cause the water droplets to break and exacerbate emulsification. The regulation principle can be to regulate according to the water content at different heights, and specifically can be obtained through experiments.

[0094] Although the specific implementation manners of the present invention are described above in conjunction with the accompanying drawings, it is not a limitation to the protection scope of the present invention. Those skilled in the art should understand that based on the technical solution of the present invention, various modifications or deformations that can be made by those skilled in the art without creative efforts are still within the protection scope of the present invention.

Claims

1. An ultrasound and electric field coupling demulsification method, characterized in that: The following steps are involved: Step 1, applying an ultrasonic field and an electric field simultaneously to the emulsion to be treated in the same area; Step 2: adjusting the ultrasonic parameters to a range that produces a steady-state cavitation effect in the emulsion, and adjusting the electric field parameters to a range that promotes effective electrical aggregation of water droplets in the emulsion, and utilizing the ultrasonic cavitation effect and the electric field polarization effect to synergistically demulsify the emulsion; Alternatively, the ultrasonic parameters are adjusted to a range where a standing wave field is formed in the emulsion, and the electric field parameters are adjusted to a range where water droplets in the emulsion are effectively electrically aggregated, so that the emulsion is synergistically demulsified by utilizing the ultrasonic mechanical effect and the electric field polarization effect; Step 3: Separate the oil and water of the emulsion after demulsification in step 2.

2. The ultrasonic and electric field coupling demulsification method according to claim 1, characterized in that: The ultrasonic field and the electric field are arranged vertically.

3. An ultrasound and electric field coupling demulsification module, used to implement the demulsification method according to claim 1 or 2, characterized in that: It comprises at least one ultrasonic and electric field coupled demulsification unit, and the unit comprises an electrode plate, a transducer, an acoustic matching plate, an acoustic reflecting plate and a protective shell; the electrode plate, the acoustic matching plate and the acoustic reflecting plate surround a flow channel, the electrode plates are arranged in pairs opposite to each other, the acoustic matching plate and the acoustic reflecting plate are arranged opposite to each other, the transducer is located outside the flow channel and mounted on the acoustic matching plate, a protective shell is arranged outside the transducer, the electrode plate is used to apply an electric field to the emulsion in the flow channel, the transducer is used to apply an ultrasonic field to the emulsion in the flow channel, and the electric field and the ultrasonic field are used to collaboratively demulsify the emulsion in the flow channel.

4. The ultrasonic and electric field coupling demulsification module according to claim 3, characterized in that: The electrode plate is relatively vertically arranged, and the acoustic matching plate and the acoustic reflection plate are relatively horizontally arranged.

5. The ultrasonic and electric field coupling demulsification module according to claim 4, characterized in that: The electrode plate is relatively horizontally arranged, and the acoustic matching plate and the acoustic reflection plate are relatively vertically arranged.

6. The ultrasonic and electric field coupling demulsification module according to claim 4, characterized in that: When the ultrasonic mechanical effect is used, the distance between the acoustic matching plate and the acoustic reflecting plate is an integer multiple of half the wavelength of ultrasound in the emulsion.

7. The ultrasonic and electric field coupling demulsification module according to claim 3, characterized in that: At least one transducer is installed on the acoustic matching plate, and the transducers can share a protective shell for protection.

8. The ultrasonic and electric field coupling demulsification module according to claim 3, characterized in that: When a plurality of ultrasonic and electric field coupling demulsification units are provided, adjacent ultrasonic and electric field coupling demulsification units can share electrode plates, and the electrode plates are arranged alternately according to high-voltage electrode plates and low-voltage electrode plates.

9. A separation device, comprising the ultrasonic and electric field coupled demulsification module according to any one of claims 4 to 8, characterized in that: The ultrasonic and electric field coupling demulsification module is arranged in the emulsion layer area of ​​the separation device according to the cross-sectional characteristics of the separation device, and the flow channel direction in the ultrasonic and electric field coupling demulsification module is consistent with the flow direction of the emulsion in the separation device.

10. The separation device according to claim 9, characterized in that The ultrasound and electric field coupling demulsification module adjusts ultrasound parameters and electric field parameters according to the emulsion characteristics of different cross-sectional areas of the separation device.

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