A crude oil electric dehydration device and method of high-voltage narrow pulse string polarity reversal electric field

Abstract

The present application relates to crude oil application pulse high pressure electric dehydration technical field, especially in kind of high voltage narrow pulse string polarity reversal electric field crude oil electric dehydration device and method. The device includes: pulse power supply and crude oil electric dehydrator, the inside of crude oil electric dehydrator is provided with high voltage electrode plate and ground electrode plate in parallel, its surface is distributed with oil inlet, oil outlet, water outlet, and crude oil electric dehydrator can realize dynamic dehydration;Pulse power supply includes voltage regulating rectifier inverter module, boost module, polarity reversal module, and pulse power supply can realize the adjustment of frequency, polarity, pulse string intermittent time. Compared with conventional pulse electric field, the crude oil electric dehydration device and method provided by the present application can realize short-time high field strength effect, avoid field strength attenuation effect caused by electrode insulation layer, form effective dehydration electric field more quickly, reduce power consumption, weaken the corrosion of electric field to equipment by adjusting pulse parameters, and obtain better dehydration effect by promoting water droplet coalescence speed.

Description

Technical Field

[0001] This invention relates to the technical field of crude oil electro-dehydration using pulsed high voltage, and particularly to a crude oil electro-dehydration device and method using a high-voltage narrow pulse train polarity reversal electric field. Background Technology

[0002] Currently, in practical applications, crude oil electrostatic dehydration processes often employ methods such as AC electric field dehydration, DC electric field dehydration, AC / DC composite electric field dehydration, or high-voltage narrow-pulse electric field dehydration. AC electric field dehydration involves boosting the AC power frequency to the required high voltage and applying it to the dehydration electrodes. The advantage of this method is that it eliminates the need for circuit rectification, making it convenient. Due to the continuous change in the electric field, water droplets in the emulsion do not form water chains, thus achieving good dehydration results for medium-to-high water content crude oil emulsions. However, its disadvantage is high energy consumption. DC electric field dehydration involves boosting the AC voltage, rectifying it, and then applying the voltage to the electrodes. This method has high dehydration efficiency but is prone to water chain formation and electrode corrosion. AC / DC composite electric field dehydration applies DC to the upper electrode and AC to the lower electrode. It leverages the dehydration characteristics of AC and DC electric fields, treating the lower layer of crude oil with high water content with AC and the upper layer with low water content with DC, simply highlighting the independent characteristics of each.

[0003] High-voltage narrow-pulse electric field dehydration involves applying AC voltage to the electrodes after boosting, rectifying, and inverting the voltage. This method has the advantage of providing medium-to-high water content dehydration capabilities compared to the three methods mentioned above, with high dehydration efficiency and a relatively short dehydration time. Due to the short pulse rise time, it has a greater impact on the oscillation of water droplets. However, if the pulse duration is too long, the water droplets are prone to secondary breakage due to continuous energy injection, resulting in low dehydration efficiency in the initial stage of dehydration. Furthermore, the use of insulated electrodes leads to a rapid attenuation effect of the electric field. While this avoids field collapse, it significantly reduces the oil-water separation efficiency. To address these shortcomings, a high-voltage narrow-pulse series polarity-reversed electric field crude oil electro-dehydration device and method are proposed. Summary of the Invention

[0004] (a) Technical problems to be solved This invention provides a crude oil electro-dehydration device and method with a high-voltage narrow-pulse polarity reversal electric field, which avoids the defects of existing methods, such as continuous injection of water droplets due to excessively long pulse duration, or rapid attenuation of the electric field due to the use of insulated electrodes, resulting in low dehydration efficiency and low oil-water separation efficiency due to secondary rupture of water droplets in the early stage of dehydration.

[0005] (II) Technical Solution To address the above problems, this invention provides a crude oil electro-dehydration device with a high-voltage narrow-pulse train polarity reversal electric field, comprising: A pulse power supply is provided, connected to a high-voltage lead. The high-voltage lead passes through a high-voltage explosion-proof cylinder, which is installed on the crude oil electrostatic dehydrator. A high-voltage bushing is connected inside the high-voltage explosion-proof cylinder, through which the high-voltage lead passes. The high-voltage lead is connected to a high-voltage electrode plate, which is installed inside the crude oil electrostatic dehydrator. A grounding electrode plate is located inside the crude oil electrostatic dehydrator, below the high-voltage electrode plate. An oil inlet and a water outlet are respectively located at both ends of the bottom of the crude oil electrostatic dehydrator. Crude oil emulsion is introduced into the crude oil dehydrator through the oil inlet, and an oil outlet is located above the water outlet.

[0006] Preferably, the pulse power supply includes a voltage-regulating rectifier-inverter module, a boost module, and a polarity reversal module. The voltage-regulating rectifier-inverter module is connected to the boost module through a current-limiting reactor, and the boost module is connected to the polarity reversal module.

[0007] Preferably, the voltage-regulating rectifier-inverter module includes a phase-shifting voltage-regulating rectifier unit, a first-stage filter unit, and an inverter unit. The phase-shifting voltage-regulating rectifier unit is connected to the first-stage filter unit and the inverter unit, and the first-stage filter unit is connected to the inverter unit.

[0008] Preferably, the voltage-regulating rectifier inverter module controls the current output through a phase-shifting voltage-regulating rectifier unit, the voltage-regulating rectifier inverter module stabilizes the voltage through a first-stage filter unit, and the voltage-regulating rectifier inverter module controls the AC frequency of the full-bridge inverter circuit through an inverter unit.

[0009] Preferably, the step-up module is a high-frequency step-up transformer, which includes a primary side of a high-frequency step-up transformer, a secondary side of a first high-frequency step-up transformer, and a secondary side of a second high-frequency step-up transformer. The primary side of the high-frequency step-up transformer is connected to a current-limiting reactor, and the secondary sides of the first and second high-frequency step-up transformers are both independent windings.

[0010] Preferably, the polarity reversal module includes a first high-voltage silicon stack and a second high-voltage silicon stack. The two ends of the first high-voltage silicon stack are respectively connected to the secondary side of a first high-frequency step-up transformer and a first switch. The second high-voltage silicon stack is respectively connected to the secondary side of a second high-frequency step-up transformer and a second switch. The first switch and the second switch are connected together to a high-voltage lead.

[0011] Preferably, the polarity reversal module outputs a positive high-voltage narrow pulse train through a first high-voltage silicon stack, and the polarity reversal module outputs a negative high-voltage narrow pulse train through a second high-voltage silicon stack.

[0012] Preferably, both the pulse power supply and the grounding electrode plate are provided with grounding wires.

[0013] This invention also provides a dehydration method for crude oil electro-dehydration devices based on high-voltage narrow-pulse train polarity reversal electric fields, comprising: Step S1: Turn on the pulse power supply. The three-phase power passes through the voltage regulation rectifier inverter module, the boost module and the polarity reversal module in sequence to generate a high-voltage narrow pulse train that can reverse polarity. Step S2: The high-voltage narrow pulse train from step S1 is conducted to the crude oil electric dehydrator through the high-voltage lead, and a high-voltage narrow pulse train polarity reversal electric field is formed inside the crude oil electric dehydrator; Step S3: In the polarity reversal electric field, the high-voltage narrow pulse train can make the water droplets in the crude oil emulsion come into contact with the high-voltage electrode plate and become charged water droplets. Under the action of the electric field force, the charged water droplets move towards the grounded electrode plate. The charged water droplets in motion collide with each other and undergo electrophoretic aggregation. Step S4: Under the action of an electric field, water droplets in crude oil emulsion are polarized. The two ends of the polarized water droplets have polarization charges of different polarities. The polarized water droplets attract each other and undergo dipole coalescence. Step S5: The direction of the electric field changes through polarity reversal, and the electric field tension on the water droplets in the crude oil emulsion changes synchronously, causing the shape of the water droplets to elastically stretch and oscillate, and the water droplets to oscillate and coalesce. Step S6: According to steps S3 to S5, water droplets in the crude oil emulsion continuously coalesce. Under the action of gravity, all the coalesced water droplets fall to the bottom of the crude oil electrostatic dehydrator, forming a water layer and completing the oil-water separation. The separated water flows out from the water outlet, and the crude oil flows out from the oil outlet.

[0014] (III) Beneficial Effects The crude oil electro-dehydration device and method with high-voltage narrow-pulse polarity reversal electric field provided by this invention can form an effective dehydration electric field more quickly compared with conventional pulse electric fields, effectively achieving a short-term high field strength effect and eliminating the sharp attenuation effect of the electrode insulation layer on the field strength. At the same time, this method can make the crude oil emulsion aggregate more quickly, effectively avoiding the formation of water chains between electrodes, improving the stability of the electric field, and further improving the dehydration efficiency. In addition, combined with the intermittent nature of the pulse train, it also reduces the consumption of electrical energy. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of the crude oil electro-dehydration device with high-voltage pulse train polarity reversal electric field of the present invention; Figure 2 This is a circuit diagram of the high-voltage pulse train polarity reversal pulse power supply of the present invention; Figure 3 This is a schematic diagram of the electric field of the high-voltage pulse train polarity reversal according to the present invention; Figure 4A schematic diagram of a high-duty-cycle high-voltage pulse electric field generated by existing technology; Figure 5 A schematic diagram of water droplet deformation under a high-duty-cycle high-voltage pulsed electric field generated by existing technology; Figure 6 A schematic diagram of a low-duty-cycle high-voltage pulse electric field generated by existing technology; Figure 7 A schematic diagram of water droplet deformation under a small duty cycle high-voltage pulsed electric field generated by existing technology; Figure 8 This is a schematic diagram of the electric field under the polarity reversal electric field of a high-voltage pulse train according to an embodiment of the present invention; Figure 9 This is a schematic diagram of the coalescence oscillation between water droplets under a high-voltage pulse train polarity reversal electric field according to an embodiment of the present invention; Figure 10 This is a schematic diagram of water droplet motion and water chain formation under the action of a high-voltage pulsed electric field generated by existing technology. Figure 11 A schematic diagram of water droplets generated by existing technology coalescing and settling under the action of dipole force; Figure 12 This is a schematic diagram of water droplet coalescence under the action of a high-voltage pulse train polarity reversal electric field according to an embodiment of the present invention; Figure 13 This is a schematic diagram illustrating the formation of water droplets and the elimination of water chains under the action of a high-voltage pulse train polarity reversal electric field, according to an embodiment of the present invention.

[0016] In the diagram: 1-Pulse power supply; 2-Crude oil electrostatic dehydrator; 3-High-voltage electrode plate; 4-Oil outlet; 5-Water outlet; 6-Oil inlet; 7-High-voltage bushing; 8-High-voltage explosion-proof cylinder; 9-High-voltage lead wire; 10-Grounding electrode plate; 11-SCR; 12-Third switch; 13-Fourth switch; 14-Filter capacitor; 15-Current-limiting reactor; 16-Primary side of high-frequency step-up transformer; 17-Secondary side of first high-frequency step-up transformer; 18-Secondary side of second high-frequency step-up transformer; 19-First high-voltage silicon stack; 20-Second high-voltage silicon stack; 21-First switch; 22-Second switch. Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] Figure 1 This is a schematic diagram of the crude oil electro-dehydration device with high-voltage narrow-pulse train polarity reversal electric field of the present invention, as shown below. Figure 1As shown, the present invention provides a crude oil electro-dehydration device with a high-voltage narrow pulse train polarity reversal electric field, comprising: A pulse power supply 1 is connected to a high-voltage lead 9, which passes through a high-voltage explosion-proof cylinder 8. The high-voltage explosion-proof cylinder 8 is installed on the crude oil electrostatic dehydrator 2. A high-voltage sleeve 7 is connected inside the high-voltage explosion-proof cylinder 8, and the high-voltage lead 9 passes through the high-voltage sleeve 7. The high-voltage lead 9 is connected to a high-voltage electrode plate 3, which is installed inside the crude oil electrostatic dehydrator 2. A grounding electrode plate 10 is provided inside the crude oil electrostatic dehydrator 2, located below the high-voltage electrode plate 3. An oil inlet 6 and a water outlet 5 are respectively provided at both ends of the bottom of the crude oil electrostatic dehydrator 2, and an oil outlet 4 is provided above the water outlet 5.

[0019] In this dehydration device, the high-voltage electrode plate 3 and the grounding electrode plate 10 are both stainless steel plates, and the high-voltage bushing 7 is a polytetrafluoroethylene bushing. In actual application, crude oil emulsion enters the crude oil electrostatic dehydrator 2 through the oil inlet 6. After dehydration, the separated water flows out from the water outlet 5, and the crude oil flows out from the oil outlet 4.

[0020] Figure 2 The circuit diagram of the high-voltage pulse train polarity reversal pulse power supply of the present invention is as follows: Figure 2 As shown, in practical applications, the pulse power supply 1 includes a voltage regulating rectifier inverter module, a boost module, and a polarity reversal module. The voltage regulating rectifier inverter module includes a phase-shifting voltage regulating rectifier unit, a first-stage filter unit, and an inverter unit. The boost module includes a primary side 16 of a high-frequency boost transformer, a secondary side 17 of a first high-frequency boost transformer, and a secondary side 18 of a second high-frequency boost transformer. The polarity reversal module includes a first high-voltage silicon stack 19 and a second high-voltage silicon stack 20. Meanwhile, both the pulse power supply 1 and the grounding electrode plate 10 are provided with grounding wires.

[0021] It should be noted that the polarity reversal module passes through the first high-voltage silicon stack 19 and the second high-voltage silicon stack 20. The two ends of the first high-voltage silicon stack 19 are respectively connected to the first switch 21 and the secondary side 17 of the first high-frequency step-up transformer. The second high-voltage silicon stack 20 is respectively connected to the second switch 22 and the secondary side 18 of the second high-frequency step-up transformer. The first switch 21 and the second switch 22 are connected to the high-voltage lead 9. The high-voltage lead 9 passes through the high-voltage explosion-proof cylinder 8 installed on the crude oil electric dehydrator 2, and then connects to the high-voltage electrode plate 3 through the high-voltage bushing 7.

[0022] In practical applications, the polarity reversal module outputs a positive high-voltage narrow pulse train through the first high-voltage silicon stack 19 via single-phase rectification; the polarity reversal module outputs a negative high-voltage narrow pulse train through the second high-voltage silicon stack 20 via single-phase rectification.

[0023] This invention also provides a dehydration method using a high-voltage narrow-pulse train polarity reversal electric field, specifically including: Step S1: Turn on the pulse power supply 1. The three-phase power passes through the voltage regulation rectifier inverter module, the boost module and the polarity reversal module in sequence to generate a high-voltage narrow pulse train that can reverse polarity.

[0024] In this method, such as Figure 2 As shown, the rectifier-filter unit includes a thyristor 11 composed of SCRA-SCRC and DA-DC, and a filter circuit composed of filter capacitor 14; the inverter section includes VT1-VT4 and VD1-VD4.

[0025] In practical applications, the thyristor 11 is a high-power voltage-regulating thyristor, forming a phase-shift voltage-regulating rectifier unit, the filter capacitor 14 is a large-capacity filter capacitor, forming the first-stage filter unit, VT1-VT4 together form the third switch 12, and VD1-VD4 together form the fourth switch 13. The third switch 12 and the fourth switch 13 are both high-power switching devices IGBTs connected in series.

[0026] In this method, the phase-shifting voltage regulation rectifier unit is connected to the first-stage filter unit and the inverter unit. The first-stage filter unit is connected to the inverter unit. In practical applications, the voltage regulation rectifier inverter module controls the current output mode through the phase-shifting voltage regulation rectifier unit, stabilizes the voltage through the first-stage filter unit, and controls the AC frequency of the full-bridge inverter circuit through the inverter unit.

[0027] In practical applications, the phase-shifting voltage regulation rectifier unit can control the current to change from AC to DC, the first-stage filter unit can filter out unimportant waves in the circuit, the inverter unit adjusts the interval time of the high-frequency pulse train by controlling the AC frequency of the full-bridge inverter circuit, and the inverter unit is connected to the high-frequency boost converter.

[0028] Additionally, it should be noted that the high-frequency boost converter includes a primary side 16 of the high-frequency boost converter, a secondary side 17 of the first high-frequency boost transformer, and a secondary side 18 of the second high-frequency boost transformer. The primary side 16 of the high-frequency boost converter, the secondary side 17 of the first high-frequency boost transformer, and the secondary side 18 of the second high-frequency boost transformer are connected by magnetic induction.

[0029] In this method, the primary side 16 of the high-frequency boost transformer is connected in series with the current-limiting reactor 15. The secondary side 17 of the first high-frequency boost transformer and the secondary side 18 of the second high-frequency boost transformer are both independent windings. Since they do not work at the same time, they do not affect each other. After obtaining high voltage, they enter the polarity reversal module. At the same time, in practical applications, the positive high voltage narrow pulse series and the negative high voltage narrow pulse series can improve their reverse withstand voltage capability through the first switch 21 and the second switch 22. The polarity reversal is achieved by using the alternating switching operation of the two switching elements.

[0030] In practical applications, both the first switch 21 and the second switch 22 are composed of high-voltage switching devices IGBTs connected in series, such as... Figure 2 As shown, the first switch is VT5 and the second switch is VT6. The two switches can be switched in polarity and controlled in terms of pulse train duration by the anti-shoo-through IGBT drive module.

[0031] It is important to note that IGBT (Insulated Gate Bipolar Transistor) is a composite, fully controllable, voltage-driven power semiconductor device composed of BJT (Bipolar Junction Transistor) and MOS (Insulated Gate Field Effect Transistor). It combines the advantages of high input impedance of MOSFET and low on-state voltage drop of GTR. It has low drive power and low saturation voltage, making it very suitable for applications in converter systems with DC voltage of 600V and above, such as AC motors, frequency converters, switching power supplies, lighting circuits, traction drives, and other fields.

[0032] Step S2: The high-voltage narrow pulse train from step S1 is conducted to the crude oil electric dehydrator 2 through the high-voltage lead 9, and a high-voltage narrow pulse train polarity reversal electric field is formed inside the crude oil electric dehydrator 2.

[0033] Step S3: In the polarity reversal electric field, the high-voltage narrow pulse train can make the water droplets in the crude oil emulsion come into contact with the high-voltage electrode plate 3 and become charged water droplets. Under the action of the electric field force, the charged water droplets move towards the grounded electrode plate 10. The moving charged water droplets collide with each other and undergo electrophoretic aggregation.

[0034] Step S4: Under the action of an electric field, water droplets in crude oil emulsion are polarized. The two ends of the polarized water droplets have polarization charges of different polarities. The polarized water droplets attract each other and undergo dipole coalescence.

[0035] Step S5: The direction of the electric field changes through polarity reversal, and the electric field pull on the water droplets in the crude oil emulsion changes synchronously, causing the shape of the water droplets to elastically stretch and oscillate, and the water droplets oscillate and coalesce.

[0036] Step S6: According to steps S3 to S5, water droplets in the crude oil emulsion continuously coalesce. Under the action of gravity, all the coalesced water droplets fall to the bottom of the crude oil electrostatic dehydrator 2, forming a water layer and completing the oil-water separation. The separated water flows out from the water outlet 5, and the crude oil flows out from the oil outlet 4.

[0037] Figure 3 This is a schematic diagram of the electric field of the high-voltage pulse train polarity reversal of the present invention, as shown below. Figure 3As shown, on the vertical axis, Uc represents the highest effective electric field strength, and the region above Uc is the electrically dispersed region; Ua represents the lowest effective electric field strength, and the region from 0 to Ua is the ineffective electric field; Ub represents the low-voltage electric field established when the water content is high, and the region between Ua and Ub is the effective electric field. In this method, we take... Figure 3 For example, at this time, Ub is the amplitude of the pulse electric field, and T0 is the duration of the positive and negative pulses under the same amplitude and polarity reversal. In practical applications, the voltage regulating rectifier inverter mode adjusts the DC amplitude of the rectifier filter output, the initial dehydration amplitude Ub of the pulse train, the high-efficiency dehydration amplitude Uc, and the duration T0 by controlling the phase angle of the phase-shifting voltage regulating unit. The application frequency of the narrow pulse at times T1 and T2 is realized by adjusting the frequency of the inverter section. The duration T1 and T2 of the pulse train are adjusted by the frequency and time of the first switch 21 and the second switch 22 when they are turned on and off.

[0038] This invention controls the amplitude of the boost module, adjusts the frequency of the inverter module, and changes the on and off durations of the first and second switches to output electrical parameters with different amplitudes, frequencies, and duty cycles. This ensures that the high-frequency pulse electric field falls between the highest field strength and the effective electric demulsification field strength of the crude oil emulsion, thereby improving the efficiency of crude oil dehydration.

[0039] In actual production, this high-voltage narrow-pulse train polarity reversal electric field crude oil electro-dehydration device has been tested and applied. The following is a detailed description of the comparison between this high-voltage narrow-pulse train polarity reversal electric field dehydration method and existing technologies: Figure 4 A schematic diagram of a high-duty-cycle high-voltage pulse electric field generated by existing technology. Figure 5 This is a schematic diagram of the deformation of a water droplet under a high-duty-cycle high-voltage pulsed electric field generated by existing technology. Figure 6 This is a schematic diagram of a small duty cycle high-voltage pulse electric field generated by existing technology. Figure 7 This is a schematic diagram of the deformation of a water droplet under a small duty cycle high-voltage pulsed electric field generated by existing technology. Figure 10 This diagram illustrates the movement of water droplets and the formation of water chains under the influence of a high-voltage pulsed electric field generated by existing technology. Figure 11 This is a schematic diagram illustrating the coalescence and sedimentation of water droplets generated by existing technology under the action of a dipole force. Figures 4 to 7 As shown, and according to Figures 10 to 11 As shown, the application of existing technologies will be introduced first.

[0040] In this embodiment, Figure 4 In this context, t0 represents the initial time of the large duty cycle pulse electric field generation; t0~t1, t1~t2, and t2~t3 represent different stages of the positive pulse duration; t3~t4 and t7~t8 represent the pulse rest time; and t4~t5, t5~t6, and t6~t7 represent different stages of the negative pulse duration. Figure 5In the equation, t0 is the initial time when the small duty cycle pulse electric field is generated; t0~t1 and t1~t2 are the durations of the positive pulse; t2~t3 and t5~t6 are the pulse rest times; and t3~t4 and t4~t5 are different stages of the duration of the negative pulse.

[0041] In practical applications, by Figures 4 to 7 It can be seen that in the high-frequency electric field generated by the existing technology, because the pulse duration is too long, the water droplets easily absorb too much energy, resulting in excessive deformation and low-electric dispersion. Because the duration is too short, the droplet deformation is insufficient, causing the water droplets to stretch and collide, which greatly reduces the coalescence efficiency between water droplets.

[0042] At the same time, by Figure 10 and Figure 11 It can be seen that, generally speaking, the high-voltage pulsed electric fields generated by existing technologies can be divided into pulsed electric fields with large duty cycles and pulsed electric fields with small duty cycles. In pulsed electric fields with large duty cycles, the dehydration electric field takes a long time to establish, and the short rest time makes it difficult for the water chain to dissipate, resulting in the formation of the water chain and the waste of electrical energy. However, in pulsed electric fields with small duty cycles, the initial dehydration efficiency is reduced, and the long rest period allows the water droplets to completely recover to a spherical shape, which is not conducive to the next water droplet stretching, thus also reducing the dehydration efficiency.

[0043] Figure 8 This is a schematic diagram of the electric field under the polarity reversal electric field of a high-voltage pulse train according to an embodiment of the present invention. Figure 9 This is a schematic diagram of the coalescence and oscillation between water droplets under a high-voltage pulse train polarity reversal electric field according to an embodiment of the present invention. Figure 12 This is a schematic diagram of water droplet coalescence under the action of a high-voltage pulse train polarity reversal electric field according to an embodiment of the present invention. Figure 13 This is a schematic diagram illustrating water droplet ripple formation and water chain elimination under the action of a high-voltage pulse train polarity reversal electric field, according to an embodiment of the present invention. Figures 8 to 9 As shown, and according to Figure 12 and Figure 13 As shown below, the practical application of this dehydration method will be described in detail.

[0044] In this embodiment, as Figure 8 and Figure 9As shown, from t0 to t1, the droplet becomes polarized and begins to deform under the influence of a positively polarized pulsed electric field; from t1 to t2, the polarization charge generated by the droplet's polarization continues to attract the droplet under the action of dipole coalescence. Simultaneously, the discharge of current in the electric field continuously provides the droplet with a certain amount of sustaining energy, allowing the deformation to be maintained and dipole coalescence to occur; from t2 to t3, the droplet is again impacted by a rising pulsed electric field, producing a certain amplitude of oscillation. Based on the original dipole coalescence, the deformation increases, and the droplet coalesces into a larger droplet; and so on. From t3 to t4, the electric field disappears, and from t4 to t... At t5, the water droplets are again subjected to polarization charges, which accelerates the completion of dipole coalescence between the droplets. From t5 to t6, the polarity begins to reverse. From t6 to t7, the droplets are polarized and begin to deform under the influence of the negative electric field, resulting in dipole coalescence and oscillating coalescence. The strong oscillations generated by the water droplets during the electric field reversal can increase the speed of collisions and film rupture between droplets. From t7 to t8, the electric field disappears, and from t8 to t9, the electric field reappears. During this process, the water droplets generate impact coalescence multiple times during the collision process, and use the inertia during the impact to accelerate the coalescence speed.

[0045] In practical applications, such as Figure 12 and Figure 13 As shown, water chains can easily form between water droplets at a certain moment. By reasonably controlling the on and off time of the polarity reversal switch, a high-frequency pulse train dehydration electric field can be quickly established, which not only effectively avoids the generation of water chains, but also improves the dehydration efficiency of crude oil and avoids leakage of inter-electrode current and collapse of the electric field.

[0046] In the early stages of dehydration, high-frequency pulse trains require only a short polarity reversal waiting time, resulting in good dehydration efficiency and minimizing the formation of water chains. In the later stages of dehydration, wider high-frequency pulses and longer polarity reversal waiting times lead to better dehydration efficiency, and the lower water content prevents water chains from forming. This demonstrates that the polarity reversal electric field of high-voltage pulse trains can fully leverage the flexible adjustability of the electric field parameters. In practical applications, by adjusting the parameters according to the real-time dynamic voltage and current changes during crude oil electro-dehydration, dehydration efficiency can be further improved, and the problem of electric field collapse can be solved.

[0047] The crude oil electro-dehydration device and method with high-voltage narrow-pulse polarity reversal electric field provided by this invention can form an effective dehydration electric field more quickly than conventional pulse electric fields, effectively achieving a short-term high field strength effect and eliminating the sharp attenuation effect of the electrode insulation layer on the field strength. At the same time, this method can make the crude oil emulsion aggregate more quickly, effectively avoiding the formation of water chains between electrodes, improving the stability of the electric field, and further improving the dehydration efficiency. In addition, combined with the intermittent nature of the pulse train, it also reduces the consumption of electrical energy.

[0048] Furthermore, the amplitude, frequency, and duty cycle parameters of the high-voltage narrow-pulse polarity reversal electric field used in this invention are adjustable, which can increase the range of water content in the treated liquid. At the same time, based on the changes in current during the formation of the water chain in the dehydration process, the quality of the purified oil can be improved by adjusting the pulse amplitude and duration, and the corrosion of the equipment by the conventional DC electric field can be reduced.

[0049] The above embodiments are only used to illustrate the present invention and are not intended to limit the present invention. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, all equivalent technical solutions also fall within the scope of the present invention, and the patent protection scope of the present invention should be defined by the claims.

Claims

1. A crude oil electro-dehydration device with a high-voltage narrow-pulse train polarity reversal electric field, characterized in that, include: A pulse power supply (1) is connected to a high-voltage lead (9). The high-voltage lead (9) passes through a high-voltage explosion-proof cylinder (8). The high-voltage explosion-proof cylinder (8) is installed on the crude oil electric dehydrator (2). The interior of the high-voltage explosion-proof cylinder (8) is connected to a high-voltage sleeve (7). The high-voltage lead (9) passes through the high-voltage sleeve (7). The high-voltage lead (9) is connected to a high-voltage electrode plate (3). The high-voltage electrode plate (3) is installed inside the crude oil electric dehydrator (2). The interior of the crude oil electric dehydrator (2) is provided with a grounding electrode plate (10). The grounding electrode plate (10) is below the high-voltage electrode plate (3). The bottom of the crude oil electric dehydrator (2) is provided with an oil inlet (6) and a water outlet (5) at both ends. The crude oil electric dehydrator (2) is filled with crude oil emulsion through the oil inlet (6). An oil outlet (4) is provided above the water outlet (5). The pulse power supply (1) includes a voltage regulating rectifier inverter module, a boost module and a polarity reversal module. The voltage regulating rectifier inverter module is connected to the boost module through a current limiting reactor (15), and the boost module is connected to the polarity reversal module. The boost module is a high-frequency boost transformer, which includes a primary side (16), a secondary side (17) of a first high-frequency boost transformer, and a secondary side (18) of a second high-frequency boost transformer. The primary side (16) of the high-frequency boost transformer is connected to a current-limiting reactor (15). The secondary side (17) of the first high-frequency boost transformer and the secondary side (18) of the second high-frequency boost transformer are both independent windings. The polarity reversal module includes a first high-voltage silicon stack (19) and a second high-voltage silicon stack (20). The two ends of the first high-voltage silicon stack (19) are respectively connected to the secondary side (17) of the first high-frequency step-up transformer and the first switch (21). The second high-voltage silicon stack (20) is respectively connected to the secondary side (18) of the second high-frequency step-up transformer and the second switch (22). The first switch (21) and the second switch (22) are connected to the high-voltage lead (9). The polarity reversal module outputs a positive high-voltage narrow pulse train through the first high-voltage silicon stack (19) and outputs a negative high-voltage narrow pulse train through the second high-voltage silicon stack (20).

2. The crude oil electro-dehydration device with high-voltage narrow-pulse train polarity reversal electric field according to claim 1, characterized in that, The voltage-regulating rectifier-inverter module includes a phase-shifting voltage-regulating rectifier unit, a first-stage filter unit, and an inverter unit. The phase-shifting voltage-regulating rectifier unit is connected to the first-stage filter unit and the inverter unit, and the first-stage filter unit is connected to the inverter unit.

3. The crude oil electro-dehydration device with high-voltage narrow-pulse train polarity reversal electric field according to claim 2, characterized in that, The voltage-regulating rectifier inverter module controls the current output through a phase-shifting voltage-regulating rectifier unit, stabilizes the voltage through a first-stage filter unit, and controls the AC frequency of the full-bridge inverter circuit through an inverter unit.

4. The crude oil electro-dehydration device with high-voltage narrow-pulse train polarity reversal electric field according to claim 1, characterized in that, Both the pulse power supply (1) and the grounding electrode plate (10) are equipped with grounding wires.

5. A dehydration method for crude oil electrostatic dehydration based on a high-voltage narrow-pulse train polarity reversal electric field as described in any one of claims 1-4, characterized in that, include: Step S1: Turn on the pulse power supply. The three-phase power passes through the voltage regulation rectifier inverter module, the boost module and the polarity reversal module in sequence to generate a high-voltage narrow pulse train that can reverse polarity. Step S2: The high-voltage narrow pulse train from step S1 is conducted to the crude oil electric dehydrator through the high-voltage lead, and a high-voltage narrow pulse train polarity reversal electric field is formed inside the crude oil electric dehydrator; Step S3: In the polarity reversal electric field, the high-voltage narrow pulse train can make the water droplets in the crude oil emulsion come into contact with the high-voltage electrode plate and become charged water droplets. Under the action of the electric field force, the charged water droplets move towards the grounded electrode plate. The charged water droplets in motion collide with each other and undergo electrophoretic aggregation. Step S4: Under the action of an electric field, water droplets in crude oil emulsion are polarized. The two ends of the polarized water droplets have polarization charges of different polarities. The polarized water droplets attract each other and undergo dipole coalescence. Step S5: The direction of the electric field changes through polarity reversal, and the electric field tension on the water droplets in the crude oil emulsion changes synchronously, causing the shape of the water droplets to elastically stretch and oscillate, and the water droplets to oscillate and coalesce. Step S6: According to steps S3 to S5, water droplets in the crude oil emulsion continuously coalesce. Under the action of gravity, all the coalesced water droplets fall to the bottom of the crude oil electrostatic dehydrator, forming a water layer and completing the oil-water separation. The separated water flows out from the water outlet, and the crude oil flows out from the oil outlet.

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