A wet electrostatic device and process based on acoustic wave to promote uniformity of anode tube water film

Abstract

The application discloses a kind of wet electrostatic device and process based on acoustic wave promotion anode pipe water film homogenization, belong to wet electrostatic precipitation technical field;A kind of wet electrostatic device and process based on acoustic wave promotion anode pipe water film homogenization, it includes dust remover body, is set to inner dust remover body anode pipe, cathode wire, water distribution device and acoustic wave generating device and direct current power supply;The number of anode pipe and cathode wire is at least one, and anode pipe and cathode wire are coaxial cooperation;Direct current power supply is used to apply negative high voltage direct current to cathode wire, to form corona electric field between cathode wire and anode pipe inner wall;Water distribution device is used to supply water to anode pipe inner wall to form initial water film;The number of acoustic wave generating device is at least one, and acoustic wave generating device is installed on anode pipe outer wall by coupling layer in acoustic coupling mode;It can realize active drive water film to overcome surface tension and realize circumferential and axial uniform spreading, to reduce dry spot area.

Description

Technical Field

[0001] This invention belongs to the field of wet electrostatic dust removal technology, and more specifically, relates to a wet electrostatic device and process based on sound waves to promote the homogenization of the water film in the anode tube. Background Technology

[0002] Wet electrostatic precipitators are commonly used as end-of-pipe treatment devices for industrial flue gas particulate matter emissions, especially for fine particulate matter such as PM2.5, sulfuric acid aerosols, heavy metals and their compounds. Their basic working principle is as follows: a high-voltage DC current is applied between the anode tube (collecting electrode) and the cathode wire (discharging electrode) to create a corona discharge. Particulate matter in the flue gas becomes charged in the corona region and migrates towards the grounded inner wall of the anode tube under the drive of the electric field, where it is collected. Simultaneously, a uniform and continuous water film is formed on the inner wall of the anode tube through a water distribution device. The scouring effect of this water film collects and discharges the collected particulate matter. Therefore, the uniformity, continuity, and stability of the water film on the inner wall of the anode tube have a significant impact on the dust removal efficiency and operational reliability of the wet electrostatic precipitator.

[0003] Currently, the formation of water film on the inner wall of the anode tube in wet electrostatic precipitators mainly includes the following methods: 1. Overflow weir type water distribution, where an annular overflow groove is set at the top of the anode tube, and the water overflows by gravity to form a falling film from top to bottom on the inner side of the tube wall; 2. Spray type water distribution, where water mist is sprayed onto the inner wall of the anode tube through atomizing nozzles, and the water mist gathers on the tube wall to form a film; 3. Water distribution disc type, where water is evenly distributed to the upper end of each anode tube using a porous water distribution disc; all of these rely on gravity to drive the water film to flow downwards; however, during the gravity-driven film falling process, the water film is prone to shrinkage and breakage due to the combined effects of surface tension, uneven wall micro-roughness, disturbance of incoming flue gas, and impurities in the water, forming dry spot areas; the formation of dry spots will cause the area to lose its particulate matter capture capacity, and may cause local electric field distortion, back corona discharge, or even spark breakdown, seriously affecting the safe and stable operation of the device.

[0004] To improve the uniformity of the water film, various improvement measures have been proposed in the existing technology. For example, 1. Chemical etching or coating the inner wall of the anode tube with a hydrophilic coating can reduce the water wall contact angle. However, the hydrophilic coating faces performance degradation problems caused by corrosion from acidic components in flue gas and erosion by particles during long-term operation. 2. Optimizing the structural parameters of the water distribution device can improve the initial water distribution uniformity. However, this method only works in the initial stage of water distribution. As the falling film process increases, the instability of the falling film and the capillary shrinkage effect will still lead to the deterioration of the water film. 3. Using mechanical scrapers or brush rollers to force the water film to spread can improve the film quality to a certain extent, but it will cause problems such as wear of moving parts, sealing leakage and high maintenance costs.

[0005] The acoustic flow effect, where sound waves attenuate due to viscosity in fluids, generates steady-state secondary flow. This effect has been widely applied in microfluidic mixing, ultrasonic-assisted coating, and material surface cleaning. Its basic principle is that when sound waves propagate in a viscous fluid, acoustic energy is converted into directional momentum of the fluid through viscous dissipation, forming a stable secondary flow. The driving effect of acoustic flow is particularly significant under the geometric constraints of thin liquid films—because when the liquid film thickness is comparable to the acoustic boundary layer thickness, the Reynolds stress gradient within the boundary layer can generate an effective driving force across the entire liquid film thickness range. However, there are currently no existing reports on applying the acoustic flow effect to the homogenization and control of the water film on the inner wall of the anode tube in wet electrostatic precipitators.

[0006] In summary, in existing wet electrostatic precipitator technologies, the uniformity of the water film on the inner wall of the anode tube is limited by the inherent physical instability of gravity-driven film falling. Existing improvement measures have defects such as insufficient coating durability, limited range of action, or poor reliability of moving parts. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide a wet electrostatic device and process for promoting the homogenization of water film in an anode tube based on sound waves. It can actively drive the water film to overcome surface tension and achieve uniform circumferential and axial spreading, thereby reducing dry spot areas.

[0008] The present invention provides a wet electrostatic device for promoting the homogenization of water film in an anode tube based on sound waves, comprising a dust collector body, an anode tube disposed in the inner dust collector body, a cathode wire, a water distribution device, a sound wave generating device, and a DC power supply.

[0009] There is at least one anode tube and a cathode wire, which are coaxially coupled; a DC power supply is used to apply negative high voltage DC current to the cathode wire to form a corona electric field between the cathode wire and the inner wall of the anode tube; a water distribution device is used to supply water to the inner wall of the anode tube to form an initial water film.

[0010] The number of acoustic wave generating devices is at least one. The acoustic wave generating device is installed on the outer wall of the anode tube in an acoustic coupling manner through a coupling layer. It is used to excite acoustic wave vibration in the anode tube wall. The acoustic wave vibration propagates along the tube wall, and the acoustic flow effect is excited in the water film, generating a steady-state driving force in the direction in the in-plane direction of the tube wall, driving the water film to overcome the surface tension and spread uniformly in the circumferential and / or axial directions.

[0011] As a further improvement of the present invention, it also includes a sound wave control unit; the sound wave control unit is electrically connected to the sound wave generator and communicatively connected to the water distribution device; the sound wave control unit has a preset mapping relationship between water supply flow rate, electric field operating parameters and sound wave parameters, used to adjust the frequency, power density and pulse duty cycle of the sound wave generator in real time according to the water supply flow rate signal collected in real time by the water supply flow rate sensor and / or the operating condition parameters of the wet electrostatic device; the operating condition parameters include at least one of flue gas flow rate and outlet dust concentration feedback signal; the frequency, power density and pulse duty cycle of the sound wave generator are adjusted in real time by using a pre-stored mapping table lookup or interpolation algorithm.

[0012] As a further improvement of the present invention, a flue gas inlet is provided on the lower side of the dust collector body, and a flue gas outlet is provided on the upper side of the dust collector body; the acoustic control unit is equipped with an online dust concentration monitor at the flue gas inlet and the flue gas outlet to adjust the feedback signal; when the outlet dust concentration corresponding to a certain control zone is too high, the acoustic control unit automatically increases the acoustic power density or duty cycle of that zone until the outlet dust concentration returns to the set range.

[0013] As a further improvement of the present invention, the acoustic wave generating device is a piezoelectric transducer, and multiple transducers are arranged at intervals along the axial direction of the anode tube and / or arranged in a circumferential array.

[0014] As a further improvement of the present invention, the anode tube has a circular or regular hexagonal cross-section and is made of any one of stainless steel, conductive fiberglass, conductive polypropylene, or conductive glass fiber reinforced plastic; when the anode tube is made of stainless steel, an acoustic matching layer is provided on the inner wall of the anode tube.

[0015] As a further improvement of the present invention, the acoustic matching layer adopts a silicone rubber-tungsten powder composite system, and its acoustic impedance is the geometric average of the acoustic impedance of the pipe and the water. Its acoustic impedance can be adjusted by adjusting the volume fraction of tungsten powder. The thickness of the acoustic matching layer is λ / 4, where λ is the wavelength of the sound wave.

[0016] As a further improvement of the present invention, the sound wave generating device operates at a frequency of 20kHz to 500kHz and has a power density of 0.05W / cm² to 0.1W / cm².

[0017] As a further improvement of the present invention, the sound wave generating device operates intermittently in pulse mode, with a duty cycle of 30% to 70% and a pulse period of 1s to 60s.

[0018] A wet electrostatic process based on acoustic wave-induced homogenization of anode tube water film is implemented by any of the above-mentioned wet electrostatic devices based on acoustic wave-induced homogenization of anode tube water film; it includes steps S1-S4.

[0019] Step S1: Water is supplied to the inner wall of the anode tube through the water distribution device to form an initial water film flowing from top to bottom;

[0020] Step S2: Under continuous water supply, the acoustic wave generator is installed on the outer wall of the anode tube through the coupling layer in an acoustic coupling manner. The acoustic wave generator applies acoustic wave vibration to the anode tube wall, generating acoustic flow in the water film on the inner wall of the anode tube, driving the water film to overcome surface tension and spread evenly in the circumferential and / or axial directions.

[0021] Step S3: Under the conditions of continuous water distribution and continuous application of acoustic vibration, a negative high voltage DC current is applied to the cathode wire to form a corona electric field, and electrostatic dust removal is performed on the flue gas passing through the anode tube.

[0022] Step S4: Apply acoustic vibration intermittently in pulse mode, wherein during the pulse interval, the water film that has been uniformly spread by acoustic flow is maintained in a spread state under the combined action of liquid viscous damping.

[0023] As a further improvement of the present invention, the wall thickness of the anode tube is adjusted according to the acoustic characteristics of the tube, the operating frequency of the sound wave and the target guided wave mode, so as to excite a Lamb wave or quasi-Lamb wave mode in the tube wall, which is 1 / 20 to 3 / 4 of the guided wave wavelength of the sound wave propagating in the tube; the coupling layer material is an epoxy resin-based composite material or silicone rubber.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0025] 1. By propagating sound waves in the pipe wall-water film system and through the acoustic flow effect, an active driving force is generated inside the water film, thus overcoming the problem of water film shrinkage and breakage caused by surface tension. Under the drive of acoustic flow, the water film can cover the inner wall of the anode tube, achieving a higher coverage rate under industrial conditions compared to traditional gravity falling film. The spreading effect driven by acoustic flow makes the water film distribution more uniform and thinner, reducing the water supply required to maintain an effective dust collection water film. Under the same collection efficiency, less water supply is required, while reducing the wastewater treatment load.

[0026] 2. The uniformly covered water film eliminates dry spot areas, maximizing the usable dust collection area on the inner wall of the anode tube; at the same time, the uniform water film ensures the uniform distribution of the electric field, avoiding local electric field distortion and back corona discharge, further improving the PM2.5 collection efficiency.

[0027] 3. The acoustic wave generator is a solid-state electronic device with no moving parts. It does not need to contact the water film or flue gas. It is installed on the outer wall of the anode tube, which does not increase the flow resistance inside the tube and will not cause mechanical wear or corrosion failure. It has high reliability in long-term operation.

[0028] 4. By adjusting the frequency, power density, and pulse duty cycle in real time through the acoustic control unit, the acoustic parameters of this invention can be adaptively optimized for different water supply flow rates and water quality conditions, and have good robustness to fluctuations in water hardness, suspended solids content, etc. At the same time, the pulse intermittent working mode effectively avoids pipe wall material fatigue and excessive energy consumption problems that may be caused by continuous high-power ultrasound.

[0029] 5. This invention only requires the addition of a sound wave generating device and an acoustic coupling layer to the outer wall of the anode tube, without changing the main structure and flue gas flow of the wet electrostatic precipitator, and is especially suitable for the retrofitting of existing wet electrostatic precipitator systems. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0031] Figure 2 This is a front view of the anode tube of the present invention.

[0032] Figure 3 This is a top view of the anode tube of the present invention.

[0033] Figure 4 This is a partially enlarged view of the present invention.

[0034] Explanation of the labels in the diagram:

[0035] 1. Dust collector body; 2. Anode tube; 21. Inner wall of anode tube; 22. Outer wall of anode tube; 23. Side wall of anode tube; 3. Cathode wire; 4. Water distribution device; 5. Sound wave generator; 51. Coupling layer; 6. Sound wave control unit; 7. DC power supply; 8. Flue gas inlet; 9. Flue gas outlet; 10. Drainage outlet. Detailed Implementation

[0036] Specific Implementation Example 1: Please refer to Figures 1-4 A wet electrostatic device based on sound waves to promote the homogenization of water film in an anode tube includes a dust collector body 1, an anode tube 2, a cathode wire 3, a water distribution device 4, a sound wave generator 5, and a DC power supply 7. The anode tube 2, cathode wire 3, water distribution device 4, and sound wave generator 5 are all located inside the dust collector body 1. A flue gas inlet 8 and a drain outlet 10 are provided on the lower side of the dust collector body 1, and a flue gas outlet 9 is provided on the upper side of the dust collector body 1.

[0037] There is at least one anode tube 2 and a cathode wire 3, which are coaxially coupled. The cross-section of the anode tube 2 is circular or hexagonal. A cathode wire 3 is coaxially suspended inside each anode tube 2. A negative high-voltage DC current is applied to the cathode wire 3 through a DC power supply 7, forming a non-uniform corona electric field between the cathode wire 3 and the grounded inner wall 21 of the anode tube. Preferably, the DC voltage is typically -30 kV to -80 kV.

[0038] The water distribution device 4 is located at the top of the anode tube 2 and is used to continuously supply process water to the inner wall 21 of the anode tube. The water distribution device 4 can be any one or a combination of an annular overflow trough water distributor, a perforated water distribution plate, or an atomizing nozzle.

[0039] For example, the annular overflow trough water distributor includes an annular overflow trough body, a water supply pipeline, and a flow regulating valve. The annular overflow trough body is coaxially mounted on the outer side of the top end of the anode tube 2. The upper edge of the trough body is provided with V-shaped or rectangular overflow teeth, the tooth height of which is 3-8 mm and the tooth spacing is 10-20 mm. The water supply pipeline introduces process water into the annular overflow trough. After the overflow trough is full, the water overflows evenly through the overflow teeth and flows downward along the inner wall 21 of the anode tube under the action of gravity to form an initial water film. The water supply flow rate is controlled by the flow regulating valve. The rated water supply of a single anode tube 2 is 0.5-4.0 L / min, preferably 1.0-2.0 L / min. It should be noted that the specific structural form of the water distribution device is not the core innovation of this invention. Those skilled in the art can choose any known water distribution method according to the actual working conditions, as long as it can provide the water flow required to form the initial water film to the inner wall 21 of the anode tube.

[0040] Without external acoustic vibration, the initial water film will form an uneven distribution due to surface tension contraction during descent, and local dry spots may appear.

[0041] The acoustic wave generator 5 is acoustically coupled to the outer wall 22 of the anode tube via a coupling layer 51, and is used to excite acoustic vibrations in the side wall 23 of the anode tube. The acoustic vibrations refer to mechanoelastic waves with frequencies in the ultrasonic range (≥20 kHz), which propagate in a guided mode within the side wall 23 of the anode tube. When the acoustic waves propagate to the interface between the inner wall 21 of the anode tube and the flowing water film, some of the acoustic energy is transmitted into the water film. Since the thickness of the water film (typically 200 μm to 500 μm) is much smaller than the wavelength of the sound wave in water (e.g., wavelength λ≈15 mm in water at 100 kHz), the sound waves entering the water film generate a Reynolds stress gradient along the wall direction within the water film thickness scale, driving a steady-state secondary flow—i.e., acoustic flow—within the water film. The driving force generated by this acoustic flow effect acts in the in-plane direction along the side wall 23 of the anode tube, actively counteracting the contraction caused by the surface tension of the water film, promoting uniform spreading of the water film circumferentially and axially, and fundamentally eliminating dry spots.

[0042] Acoustic flow refers to the phenomenon where steady-state fluid motion occurs due to the viscous dissipation of sound energy as sound waves propagate in a viscous fluid. In the anode tube-water film system of this invention, the generation of the acoustic flow effect includes the following steps.

[0043] 1. Acoustic wave excitation and propagation through the tube wall: The acoustic wave generating device 5 converts an electrical signal into mechanical vibration through the inverse piezoelectric effect. The vibration is transmitted to the anode tube wall 23 via the coupling layer 51. Within the tube wall, the acoustic wave propagates in a guided wave mode, and its propagation mode depends on the ratio of the tube wall thickness to the acoustic wave wavelength. In the preferred operating frequency range of this invention, from 20 kHz to 500 kHz, for an anode tube 2 with a wall thickness of 2 mm to 8 mm, the acoustic wave propagates in the tube wall in a Lamb wave or quasi-Lamb wave mode, having longitudinal and circumferential components along the tube wall.

[0044] 2. Sound waves penetrate the water film; when sound waves in the pipe wall reach the water film interface of the inner wall of anode tube 2, part of the sound wave energy is transmitted into the water film through the interface. The transmission efficiency depends on the degree of acoustic impedance matching between the pipe wall material and the water. For conductive fiberglass pipes (characteristic acoustic impedance of 3.5 MRayl), the acoustic impedance matching with water is 1.5 MRayl, which is relatively good, and the sound energy transmission coefficient is between 40% and 60%. For stainless steel pipes (characteristic acoustic impedance of 45 MRayl), the acoustic impedance mismatch is severe, and the direct transmission coefficient is less than 10%. In this case, the present invention can improve the transmission coefficient to more than 50% by setting an acoustic matching layer (whose acoustic impedance is the geometric average of the acoustic impedance of the pipe material and the water) on the inner wall of the pipe and designing the thickness of the matching layer according to the λ / 4 impedance matching principle. It should be noted that the coupling layer 51 in this specification specifically refers to the acoustic impedance matching and mechanical coupling layer between the sound wave generator and the outer wall of the anode tube. Its function is to efficiently transmit the generated mechanical vibration to the tube wall, while providing electrical insulation and mechanical fixation. The acoustic matching layer (only installed on the inner wall of the tube in the case of high acoustic impedance tubes such as stainless steel) specifically refers to the impedance transition layer added to the inner wall 21 of the anode tube when the acoustic impedance of the anode tube 2 material is severely mismatched with that of the water. Its function is to improve the sound energy transmission efficiency at the tube wall-water film interface. Both follow the λ / 4 impedance matching principle, but their placement and functional emphasis are different—the former is located on the outer wall of the tube, while the latter is located on the inner wall of the tube (between the tube and the water film). It should be further noted that the λ / 4 design of the coupling layer 51 (outer wall of the pipe) is based on the nominal resonant frequency of the acoustic wave generator 5 and the longitudinal wave velocity in the coupling layer material; the λ / 4 design of the acoustic matching layer (inner wall of the pipe) is also based on the excitation frequency of the acoustic wave generator 5 (the frequency remains constant in a linear system), but the deviation of the equivalent incident angle of the inner wall interface from the normal due to the dispersion effect during the propagation of guided waves through the pipe wall needs to be considered. When the guided wave reaches the inner wall interface of the pipe at an oblique incident angle, the effectiveness of λ / 4 matching decreases as the incident angle increases. Under the typical parameters of this invention (d / λ=0.1~0.3), the equivalent incident angle of the main guided wave modes at the inner wall interface of the pipe is less than 30°, and the transmission coefficient of the λ / 4 matching layer decreases by no more than 15% within this angle range, which can still meet the engineering requirements.

[0045] 3. Sound energy dissipation and acoustic flow driving force in water films; when sound waves transmitted through a water film propagate in a viscous water medium, their sound energy density decreases exponentially along the propagation direction. In the frequency range of 20kHz to 500kHz, the absorption coefficient of water for sound waves is proportional to the square of the frequency (α∝f²). Since the thickness of the water film (200μm to 500μm) is much smaller than the characteristic length of sound absorption, the sound energy is basically uniformly distributed throughout the entire film thickness range. The periodic pressure gradient of the sound wave is coupled with the viscous stress of the fluid, and in the acoustic boundary layer (thickness δ≈ Where ν is the kinematic viscosity of water and ω is the angular frequency of the sound wave, a net Reynolds stress is generated within the wall, driving the fluid to move along the wall direction, forming an acoustic flow. At a working frequency of 100kHz, the thickness δ of the acoustic boundary layer (also known as the viscous penetration depth) in water is approximately... The acoustic boundary layer is approximately 1.7 μm thick, much smaller than the water film thickness (200–500 μm). Within the acoustic boundary layer, the net Reynolds stress generated by the periodic velocity gradient of the sound waves coupled with fluid viscosity drives steady-state flow within the boundary layer. This flow transfers momentum to the outer main fluid through viscous coupling, exciting stable acoustic flow across the entire water film cross-section (including the Rayleigh acoustic flow component outside the boundary layer caused by the non-uniform spatial distribution of Reynolds stress). Therefore, despite the extremely thin acoustic boundary layer, the net driving force it generates can act across the entire water film cross-section through momentum transfer.

[0046] 4. Achieving uniform water film spreading: The net effect of acoustic flow driving is to generate a directional flow component within the water film along the in-vessel wall. Circumferentially, the acoustic flow causes water to migrate from areas of thicker film to areas of thinner film, automatically "filling" areas prone to dryness. Axially, the momentum added by the acoustic flow helps maintain the continuity of the water film during long-distance film falling. When the acoustic flow driving force reaches dynamic equilibrium with the surface tension of the water film, gravity, and the shear force at the gas-liquid interface, the water film achieves steady-state uniform spreading.

[0047] The following order-of-magnitude estimation verifies that the acoustic driving force is sufficient to overcome the surface tension effect: Under typical operating conditions (frequency 100kHz, power density 0.10W / cm², water film thickness 300μm), the sound intensity I = 1000W / m², and the amplitude of the acoustic particle velocity u_ac in the water = ≈0.037 m / s. Acoustic boundary layer thickness δ= ≈1.8 μm. Reynolds stress within the boundary layer. In contrast, for a film thickness difference Δh = 100 μm (corresponding to a non-uniform water film with a coverage of approximately 70%), the Laplace capillary pressure gradient driving stress along a characteristic length L = 50 mm (1 / 4 arc length of the pipe circumference) is... (Where γ = 0.073 N / m is the surface tension coefficient of water), this value is less than the acoustic flow driving force, indicating that under the stated parameters, the acoustic flow driving force is sufficient to overcome the surface tension gradient and drive spreading. The acoustic flow driving force scales linearly with the power density. It can provide power densities on the order of 4 × 10⁻⁶ W / cm² within the power density range of 0.05–0.10 W / cm². -3 ~8×10 -3 The effective driving stress of Pa. Regarding the control of the spreading direction by the guided wave modes of the pipe wall: Under the condition of CFRP pipe with a wall thickness of 4mm and a frequency of 100kHz, d / λ≈0.16, antisymmetric A0 mode (dominated by out-of-plane displacement) and symmetric S0 mode (dominated by in-plane displacement) exist simultaneously in the pipe wall. The out-of-plane displacement component of the A0 mode generates a normal sound pressure gradient after penetrating the water film, driving Schlichting acoustic flow within the acoustic boundary layer, and its net driving force is distributed tangentially along the wall surface; the in-plane displacement component of the S0 mode directly generates shear drive within the membrane through interfacial viscous coupling. Under the five-face contact excitation mode of the acoustic wave generator of this invention, a mixed guided wave field of A0 and S0 modes is simultaneously excited in the pipe wall. The acoustic flow driving force after penetrating the water film has both circumferential and axial components. The distribution ratio of the driving force in the two directions can be adjusted by adjusting the excitation frequency (using the mode selectivity of the guided wave dispersion curve) according to the actual spreading requirements.

[0048] Specific Embodiment Two: The similarities to Specific Embodiment One will not be repeated here, but the difference lies in the inclusion of an acoustic control unit 6. In this embodiment, the anode tube 2 is made of conductive fiberglass (CFRP). Preferably, the anode tube 2 has a circular cross-section, an inner diameter of 300mm, a wall thickness of 4mm, and a length of 6000mm; the cathode wire 3 is a barbed wire, coaxially installed at the center of the anode tube 2. The water distribution device 4 is an annular overflow trough type water distributor, with a rated water supply of 1.5 L / min for a single anode tube 2.

[0049] The acoustic wave generator 5 uses a PZT-4 piezoelectric ceramic transducer with a resonant frequency of 100kHz and a single-piece power capacity of 50W. The coupling layer 51 adopts an epoxy resin-alumina composite system, and its characteristic acoustic impedance after curing is 3.8 MRayl, which matches well with the acoustic impedance (3.5 MRayl) of the conductive fiberglass pipe. The thickness of the coupling layer 51 is set according to the λ / 4 impedance matching principle. For the longitudinal wave velocity in the epoxy resin composite system at a frequency of 100 kHz, which is 2500 m / s, and the wavelength λ = 25 mm, the thickness of the coupling layer 51 is set to 6 mm.

[0050] Six sets of transducers are installed axially along each anode tube 2, with an axial spacing of 1000 mm. Each set includes four transducers, evenly distributed circumferentially at the same height on the outer wall 22 of the anode tube (at 90° intervals). The transducers are in surface contact with the outer wall 22 of the anode tube through a coupling layer 51, with a coupling area of ​​25 mm × 25 mm. All transducers are connected in parallel to the acoustic wave control unit 6 via shielded cables.

[0051] The acoustic control unit 6 includes a signal generator, a power amplifier, and a microcontroller. The microcontroller has a preset mapping table of water flow rate and acoustic parameters (see Table 1). In actual operation, it automatically queries the table based on the real-time signal from the water flow sensor and outputs the corresponding operating frequency, power density, and pulse duty cycle settings.

[0052]

[0053] Table 1. Water supply flow rate - acoustic parameter mapping relationship (Example 2, FRP pipe, resonant frequency 100 kHz)

[0054] The pulse period is uniformly set to 10 seconds. The acoustic wave generator operates intermittently in pulse mode, with the duration of a single pulse being the product of the duty cycle and the pulse period (for example, when the duty cycle is 50%, 5 seconds of acoustic wave vibration is applied within each 10-second cycle, followed by a 5-second interval). By setting the interval, this intermittent operating mode can effectively reduce average energy consumption and the accumulation of thermal-mechanical fatigue in the anode tube sidewall 23 material while ensuring the water film spreading effect.

[0055] It should be noted that the selection of a 10-second pulse period is based on the ratio between the water film spreading and holding time (5–30 seconds under standard operating conditions) and the acoustic flow establishment time (<1 second). This means the pulse period is much shorter than the lower limit of the spreading and holding time, ensuring that the next pulse is applied before significant degradation of the water film. Under more severe operating conditions (such as flue gas velocity >2 m / s or water supply flow rate <1.0 L / min), the spreading and holding time may be shortened to 5–15 seconds; preferably, the pulse period is shortened accordingly to 3–8 seconds, with the upper limit of the pulse period not exceeding 50% of the spreading and holding time under the corresponding operating conditions.

[0056] Under the operating conditions of this embodiment, the power density of the acoustic vibration is 0.10 W / cm², corresponding to a standard water supply flow rate of 1.0 to 2.0 L / min. The coupling area of ​​a single transducer is 6.25 cm², and the electrical power of a single transducer is 0.625 W. The total electrical power of the 24 transducers in each pipe is 15 W. Considering the efficiency of the power amplifier and transducers, the total power consumption of the system is 50 W. This power density value is within the range of 0.05 to 0.10 W / cm².

[0057] Preferably, for water supply flow rates higher than 2.0 L / min (such as the 2.0 to 4.0 L / min range in Table 1), by increasing the pulse duty cycle from 50% to 70% and adding an additional transducer group on the outer wall 22 of the anode tube (reducing the axial spacing from 1000 mm to 800 mm), the equivalent total sound energy input can be achieved without exceeding the upper limit of 0.10 W / cm² power density, thus maintaining the water film spreading effect.

[0058] Specific Embodiment Three: The difference between this embodiment and Specific Embodiment Two is that the anode tube 2 is made of 316L stainless steel, with a regular hexagonal cross-section (300mm between opposite sides), a wall thickness of 3mm, and a length of 6000mm. The characteristic acoustic impedance of stainless steel is 45.7MRayl, far exceeding the acoustic impedance of water (1.5MRayl). Preferably, an acoustic matching layer is provided on the inner wall 21 of the anode tube to improve the sound energy transmission efficiency.

[0059] In this embodiment, the thickness of the anode tube sidewall 23 is 3 mm, which corresponds to a longitudinal wave wavelength λ of 74 mm in steel at an 80 kHz operating frequency. The wall thickness is λ / 25, which is slightly lower than λ / 20. However, at this wall thickness, the dispersion curve of the A0 mode Lamb wave in the anode tube sidewall 23 is still in the effective excitation region, and its out-of-plane displacement component is sufficient to generate the required acoustic energy transmission in the inner wall 21 of the anode tube. Experimental verification shows that at 80 kHz, the difference in water film coverage between 3 mm wall thickness (λ / 25) and 4 mm wall thickness (λ / 18.5) at the same power density is less than 3%, indicating that the λ / 25 wall thickness can still achieve effective acoustic energy coupling and transmission under the operating conditions of this embodiment.

[0060] The acoustic matching layer uses a silicone rubber-tungsten powder composite system. By adjusting the volume fraction of tungsten powder, its characteristic acoustic impedance is tuned to 8 MRayl (close to the geometric average of the acoustic impedance of water and steel). The matching layer thickness is set at λ / 4. For the longitudinal wave velocity in this composite material at a frequency of 80kHz, which is 1800 m / s, λ≈22.5 mm, the matching layer thickness is set to 5.6 mm. The matching layer is bonded to the inner wall 21 of the anode tube by a hot pressing process, and the surface is polished to ensure uniform flow of the water film on it.

[0061] The acoustic wave generator uses a PZT-8 piezoelectric ceramic transducer, which has lower dielectric loss and a higher mechanical quality factor than the PZT-4 transducer in Specific Embodiment Two. It is suitable for continuous / high duty cycle pulse operation, with a resonant frequency of 80kHz. The remaining transducer layout and control strategy are the same as in Specific Embodiment Two. The relatively low frequency of 80kHz is used to obtain a longer acoustic wavelength (longitudinal wave velocity in steel is 5900 m / s, λ≈74 mm) on the steel anode tube sidewall 23, reducing the attenuation effect of tube wall bending on acoustic energy propagation.

[0062] Specific Embodiment Four: This embodiment differs from Specific Embodiment Two in that it includes 37 anode tubes 2 arranged in a close-packed hexagonal pattern. Each anode tube 2 is equipped with an independent acoustic wave generator 5, using the specifications and transducer configuration of Specific Embodiment Two. Each anode tube 2 has 6 sets of transducers installed along its axial direction, with each set containing 4 transducers. These are managed by a zone controller, grouping 7 adjacent tubes into one group (the central tube and its surrounding 6 tubes), resulting in 6 control zones. The acoustic parameters of each control zone are independently adjustable to adapt to the uneven distribution of flue gas flow in different areas.

[0063] The acoustic control unit 6 is also adjusted based on feedback signals from online dust concentration monitors installed at the flue gas inlet 8 and flue gas outlet 9. When the dust concentration at the outlet corresponding to a certain control zone is too high, the acoustic control unit 6 automatically increases the acoustic power density or duty cycle of that zone to enhance the water film spreading effect until the dust concentration at the outlet returns to the set range.

[0064] Specific Embodiment 5: The present invention also provides a wet electrostatic process based on acoustic wave-based promotion of anode tube water film homogenization, which is implemented by any of the above-mentioned wet electrostatic devices based on acoustic wave-based promotion of anode tube water film homogenization; it includes steps S1-S4.

[0065] Step S1: Water is supplied to the inner wall 21 of the anode tube through the water distribution device 4 to form an initial water film flowing from top to bottom;

[0066] Step S2: Under continuous water supply, the sound wave generator 5 is installed on the outer wall 22 of the anode tube via the coupling layer 51 in an acoustic coupling manner. The sound wave generator 5 applies sound wave vibration to the anode tube wall 23, generating sound flow in the water film on the inner wall 21 of the anode tube, driving the water film to overcome surface tension and spread evenly in the circumferential and / or axial directions.

[0067] Step S3: Under the conditions of continuous water distribution and continuous application of acoustic vibration, a negative high voltage DC current is applied to the cathode wire 3 to form a corona electric field, and electrostatic dust removal is performed on the flue gas passing through the anode tube 2.

[0068] Step S4: Apply acoustic vibration intermittently in pulse mode. During the pulse interval, the water film that has been uniformly spread by the acoustic flow has a uniform film thickness, which makes the Laplace capillary pressure gradient disappear. The surface tension no longer drives contraction and breakage. Instead, the small disturbances are automatically attenuated by the capillary restoring force, and the spread state is maintained under the combined action of liquid viscous damping.

[0069] Preferably, the wall thickness of the anode tube 2 is adjusted according to the acoustic characteristics of the tube, the operating frequency of the sound wave and the target guided wave mode, so as to excite a Lamb wave or quasi-Lamb wave mode in the tube wall, which is 1 / 20 to 3 / 4 of the guided wave wavelength of the sound wave propagating in the tube; the coupling layer 51 is made of epoxy resin-based composite material or silicone rubber.

[0070] Experiment Example 1: Under the same anode tube specifications and flue gas conditions (flue gas from a coal-fired power plant, inlet dust concentration approximately 30 mg / Nm³, PM2.5 percentage approximately 65%, flue gas velocity 1.2 m / s, treatment temperature 50°C), a comparative experiment was conducted on two operating modes: one using acoustic waves to promote water film spreading, and the other not using acoustic waves. The experimental conditions were as follows: the anode tube was made of conductive fiberglass, with an inner diameter of 300 mm and a length of 6000 mm; the water supply flow rate was 1.5 L / min; and the flue gas SO2 concentration was 150 ppm. The experimental data are shown in Table 2. The water film coverage rate was measured and calculated using the following method: At least 10 measurement sections were selected at equal intervals along the axial direction on the inner wall of the anode tube. For each section, a panoramic image of the inner wall was acquired using an industrial endoscope and a surround-view lens (resolution no less than 1920×1080 pixels). After binarization using an image processing algorithm (grayscale threshold segmentation method, based on the grayscale difference between the wetted and dry areas), the proportion of wetted pixels to the total pixel area was calculated and defined as the local water film coverage rate of that section. The overall water film coverage rate of the entire pipe was taken as the area-weighted average of all measurement sections. The proportion of pipe sections with dry spots was defined as the percentage of measurement sections with a local water film coverage rate below 80% out of the total number of measurement sections. The above measurements were performed under steady-state operating conditions, with each set of operating conditions repeated three times and the average value taken.

[0071] It should be noted that the water supply flow rate for the control example (without acoustic vibration) in Table 2 is 2.5 L / min. This is a relatively high water supply rate typically used by traditional wet electrostatic precipitators to maintain basic dust collection functions without additional spreading measures. The water supply flow rate for the experimental example (with acoustic vibration) is 1.5 L / min, reflecting the reduction in the amount of water required to maintain the spread after acoustic flow-driven spreading. To decouple the contributions of the acoustic effect and the water-saving effect, a supplementary control experiment with the same flow rate was conducted: under the condition of the same water supply flow rate of 2.5 L / min, acoustic vibration was applied, and the water film coverage increased from 72% to 94%, and the PM2.5 collection efficiency increased from 88.5% to 97.5%, verifying the independent contribution of acoustic drive. Under the condition of the same water supply flow rate of 1.5 L / min without acoustic vibration, the water film coverage rate was only 60%, further confirming that simply reducing the water supply flow rate cannot improve the water film coverage quality. Therefore, the overall improvement in Table 2 (coverage +35%, efficiency +9.7 pp, water saving -40%) is the synergistic result of the active acoustic wave spreading effect and the water saving effect.

[0072] Water film coverage (%) 72 97 +35% Percentage of pipe sections with dry spots (%) 38 3 -92% PM2.5 capture efficiency (%) 88.5 98.2 +9.7 pp Total dust collection efficiency (%) 91.2 99.1 +7.9 pp Operating voltage fluctuation rate (%) 15.3 3.8 -75% Spark occurrence rate (times / 24 h) 12 1 -92% Water consumption per unit pipe (L / min) 2.5 1.5 -40% Power consumption of acoustic system (W / tube) 0 50 —

[0073] Table 2 Comparative experimental data of water film spreading with and without sound waves

[0074] As shown in Table 2, under the operating conditions where sound waves promote water film spreading: (1) the water film coverage rate increased significantly from 72% to 97%, and the proportion of dry spot pipe sections decreased sharply from 38% to 3%, verifying the effectiveness of sound flow driving water film uniform spreading; (2) the PM2.5 capture efficiency increased from 88.5% to 98.2%, the total dust capture efficiency increased from 91.2% to 99.1%, and the particulate matter emission concentration decreased by about an order of magnitude; (3) the operating voltage fluctuation rate and spark occurrence rate decreased by 75% and 92% respectively, indicating that the uniform water film significantly improved the spatial uniformity of the electric field and the stability of operation; (4) under the premise of achieving better capture efficiency, the water consumption per unit pipe decreased by 40%, verifying the effect of energy saving and consumption reduction; (5) although the sound wave system increased the power consumption by 50 W / pipe, compared with the efficiency and reliability gains it brought, the energy consumption cost was far less than the water saving benefits and emission reduction value. Regarding the influence of acidic water film components on acoustic properties: The acidic solution (pH approximately 2-4) formed after SO2 / SO3 dissolves in the water film in coal-fired flue gas exhibits different sound velocity and sound absorption coefficient compared to pure water. Literature data comparison shows that within the pH range of 2-4, the sound velocity variation of dilute sulfuric acid solution does not exceed ±1% of the sound velocity in pure water, and the sound absorption coefficient differs from pure water by less than 5% in the frequency band below 100 kHz. Therefore, the influence of the acidic water film on the acoustic flow driving efficiency is within an acceptable engineering range. For the acoustic matching layer (silicone rubber-tungsten powder composite system) on the inner wall of the stainless steel anode tube described in Specific Example 3, its long-term stability in acidic water film (pH 2-4, temperature 50°C) and corona discharge ozone environment was verified by accelerated aging experiments (immersion in 80°C, pH 2 sulfuric acid solution for 500 h). The acoustic impedance change of the matching layer was less than 8%, and the λ / 4 matching effect did not show significant degradation, with an expected service life of no less than 5 years. Routine maintenance should include checking the integrity of the coupling layer 51 on the outer wall of the pipe and the acoustic matching layer on the inner wall of the pipe (for stainless steel pipes).

[0075] The selection of the acoustic wave operating frequency is a key parameter affecting the water film spreading effect. Too low a frequency (<20 kHz) will result in: (a) excessively long acoustic wavelengths, complex guided wave modes in the pipe wall, and difficulty in effective coupling; (b) entry into the audible range, causing noise pollution; and (c) reduced acoustic flow driving force (due to a low acoustic absorption coefficient). Too high a frequency (>500 kHz) will result in: (a) a sharp increase in acoustic energy attenuation in the pipe wall and coupling layer, severely limiting the effective range; (b) an excessively high acoustic absorption coefficient in the water, causing acoustic energy to concentrate and dissipate within tens of micrometers near the interface, failing to effectively act across the entire water film thickness range; and (c) a significant increase in the difficulty and cost of transducer manufacturing. Based on theoretical analysis (based on the propagation characteristics of guided waves in pipe walls, the frequency dependence of acoustic absorption in water, and the scaling relationship between acoustic flow driving force and frequency) and combined with single-factor experimental verification (comparative tests on water film coverage at five frequency points of 60 kHz, 80 kHz, 100 kHz, 150 kHz, and 200 kHz, with the best overall performance at 100 kHz), the working frequency of this invention is preferably 20 kHz to 500 kHz, and more preferably 50 kHz to 200 kHz.

[0076] Acoustic vibration and corona discharge can influence each other: the mechanical vibration displacement amplitude of the anode tube wall 23 due to piezoelectric excitation at frequencies of 20–500 kHz is 10. -8 ~10 -7 The magnitude is on the order of m (estimated based on a power density of 0.10 W / cm² and the elastic modulus of the tube). This magnitude is much smaller than the cathode-anode spacing (typically 100–150 mm), and its influence on the macroscopic electric field distribution is on the order of ΔE / E≈δ / d≈10. -9 ~10 -8 This can be ignored. In the high field strength region at the tip of the cathode wire spikes (E>10), the effect is negligible. 6 The local geometric changes caused by the micro-vibration of the tube wall (V / m) are much smaller than the self-sustaining pulsation amplitude of the corona discharge itself, and will not have a detectable impact on the discharge stability. The data in Table 2, showing that the operating voltage fluctuation rate decreased from 15.3% to 3.8% after the application of acoustic waves, indirectly confirms that the acoustic vibration did not introduce any additional discharge instability; this improvement is attributed to the uniform water film eliminating the local electric field distortion in the dry spot region. Regarding the effect of the high-voltage electrostatic field on the piezoelectric transducer—the DC electric field strength at the anode tube wall is approximately 5 × 10⁻⁶. 5 V / m, which is much lower than the normalization field strength of PZT ceramics (approximately 1×10⁻⁶). 6 The transducer is mounted on the outer wall 22 of the anode tube and isolated from the anode tube wall 23 by the coupling layer 51 (electrically insulating material). The high voltage electrostatic field will not produce a detectable depolarization effect on the piezoelectric performance of the transducer.

[0077] The selection of power density needs to balance the spreading effect and energy consumption. Experiments have verified that when the power density is below 0.02 W / cm², the acoustic driving force is insufficient to effectively overcome surface tension, and the improvement in water film coverage is not significant. When the power density is above 1.0 W / cm², local cavitation may occur in the water film, which not only wastes energy but may also cause cavitation erosion damage to the pipe wall material. In addition, it is worth noting that when the acoustic power density is too high, an ultrasonic atomization effect may occur at the gas-liquid interface of the water film. When the sound wave propagates in the water film to the free surface, if the acoustic pressure disturbance at the surface exceeds the stability threshold of the liquid surface tension, it will tear the liquid film surface into tiny droplets, thereby destroying the integrity of the water film and potentially being carried downstream by the flue gas flow. Within the preferred power density range of 0.05 W / cm² to 0.1 W / cm², and with a water film thickness of 200–500 μm, the theoretically estimated sound pressure amplitude at the gas-liquid interface is lower than the ultrasonic atomization threshold in water (for a water-air interface at 100 kHz, the atomization threshold corresponds to a sound pressure amplitude on the order of 0.1–0.3 MPa, while the sound pressure amplitude corresponding to 0.1 W / cm² in this invention is 0.055 MPa, far lower than the ultrasonic atomization threshold). Furthermore, the pulsed intermittent operating mode (duty cycle 30%–70%) further reduces the average acoustic energy input, effectively avoiding the atomization risk that may result from continuous high-power excitation. This invention preferably uses a power density range of 0.05 W / cm² to 0.1 W / cm², within which the acoustic velocity and input power are approximately linearly related, facilitating control. It should be noted that the ultrasonic atomization threshold is frequency-dependent. At lower frequencies (e.g., 20 kHz), the instability threshold of surface tension waves is typically low. Within the preferred operating frequency range of 50 kHz to 200 kHz and the power density range of 0.05 W / cm² to 0.1 W / cm², theoretical estimates show that the sound pressure amplitudes at each frequency point (0.039–0.055 MPa) are all below the ultrasonic atomization threshold at the corresponding frequencies, making the risk of water film atomization negligible. In the high-frequency range (200–500 kHz), the atomization mechanism may be dominated by surface tension wave resonant breakup, but the rapid attenuation of acoustic energy (α∝f²) and the average acoustic energy reduction effect of the pulse intermittent operating mode of this invention further suppress the probability of atomization.

[0078] The introduction of the pulsed working mode has three advantages. First, it is necessary to explain the physical mechanism by which the water film maintains its spread state during the pulse interval: the effect of surface tension on the water film is two-sided—in a non-uniform water film, the Laplace capillary pressure gradient caused by the difference in film thickness drives the liquid to migrate from the thin area to the thick area, causing the water film to shrink and break, forming dry spots (this is the mechanism described in the background art); however, after uniform spreading is achieved by acoustic flow, the uniform film thickness causes the curvature gradient to disappear, and the surface tension under the condition of uniform film thickness mainly manifests as an isotropic static contractile force (unit N / m), while the liquid viscosity (unit Pa·s) dissipates the kinetic energy of the fluid motion during the dynamic process. In the initial state of uniform film thickness, a small film thickness disturbance causes a local curvature change, and the resulting capillary restoring force (on the order of γ·Δκ, where γ is the surface tension coefficient and Δκ is the curvature disturbance) drives the liquid to flow back from the thick area to the thin area, causing the disturbance to decay exponentially—the decay time constant depends on the balance between surface tension, viscous force, and film thickness. Meanwhile, the convection effect in gravity-driven falling film flow causes disturbances to propagate downstream. Within the finite time window of the pulse interval (typically 5–30 seconds, for standard operating conditions with a pipe diameter of 300 mm, a water supply flow rate of 1.0–2.0 L / min, and a flue gas velocity ≤2.0 m / s), the rate of disturbance decay due to capillary restoring force is better than the rate of disturbance growth due to falling film convective instability, and the spread water film can maintain a basically uniform state. This maintenance time is determined by a combination of theoretical estimation and experimental observation based on falling film flow stability analysis (a simplified solution of the Orr-Sommerfeld equation in the thin liquid film limit), and it increases with increasing pipe diameter, decreasing water supply flow rate, and decreasing flue gas velocity.

[0079] Based on this, the advantages of the pulse working mode include: 1. After the water film spreads to a steady state driven by acoustic flow, even if the sound wave is briefly interrupted (for several seconds to tens of seconds), the spread uniform water film will not immediately break under the aforementioned self-healing mechanism. This spreading and holding time (usually 5 to 30 seconds) is much longer than the acoustic flow establishment time (<1 second). Therefore, the pulse mode can significantly reduce the average power consumption with almost no impact on the spreading effect; 2. The pulse interval provides cooling and stress relaxation time for the anode tube wall 23 and the coupling layer 51, which is beneficial to extending the service life of the materials; 3. The intermittent working mode effectively avoids the tube wall material fatigue and excessive energy consumption problems that may be caused by continuous high-power ultrasound. After experimental optimization, the duty cycle is preferably 30% to 70%, and the pulse period is preferably 1s to 60s. The water film coverage rate increased from 68% to 96%, and the PM2.5 emission concentration decreased to 2mg / Nm³.

Claims

1. A wet electrostatic device for promoting uniformity of water film in an anode tube based on acoustic waves, characterized in that: It includes a dust collector body (1), an anode tube (2) installed in the inner dust collector body (1), a cathode wire (3), a water distribution device (4), a sound wave generating device (5), and a DC power supply (7). The number of anode tubes (2) and cathode wires (3) is at least one, and the anode tubes (2) and cathode wires (3) are coaxially coupled; a DC power supply (7) is used to apply negative high voltage DC current to the cathode wires (3) to form a corona electric field between the cathode wires (3) and the inner wall (21) of the anode tube; a water distribution device (4) is used to supply water to the inner wall (21) of the anode tube to form an initial water film; The number of sound wave generating devices (5) is at least one. The sound wave generating device (5) is installed on the outer wall (22) of the anode tube in an acoustic coupling manner through the coupling layer (51) to excite sound wave vibration in the anode tube wall (23). The sound wave vibration propagates along the tube wall, and the acoustic flow effect is excited in the water film, generating a steady driving force in the direction in the in-plane direction of the tube wall, driving the water film to overcome the surface tension and spread evenly in the circumferential and / or axial directions.

2. The wet electrostatic device for promoting uniformity of water film in an anode tube based on acoustic waves according to claim 1, characterized in that: It also includes a sound wave control unit (6); the sound wave control unit (6) is electrically connected to the sound wave generator (5) and is communicatively connected to the water distribution device (4); the sound wave control unit (6) has a preset mapping relationship between water supply flow, electric field operating parameters and sound wave parameters, which is used to collect water supply flow signals and / or operating condition parameters of wet electrostatic device in real time based on the water supply flow sensor. The operating parameters include at least one of the flue gas flow rate and the outlet dust concentration feedback signal; the frequency, power density and pulse duty cycle of the sound wave generator (5) are adjusted in real time by using a pre-stored mapping table lookup or interpolation algorithm.

3. The wet electrostatic device for promoting uniformity of water film in an anode tube based on acoustic waves according to claim 2, characterized in that: A flue gas inlet (8) is provided on the lower side of the dust collector body (1), and a flue gas outlet (9) is provided on the upper side of the dust collector body (1); the acoustic control unit (6) is equipped with an online dust concentration monitor at the flue gas inlet (8) and the flue gas outlet (9) to adjust the feedback signal; when the dust concentration at the outlet corresponding to a certain control zone is too high, the acoustic control unit (6) automatically increases the acoustic power density or duty cycle of that zone until the dust concentration at the outlet returns to the set range.

4. The wet electrostatic device for promoting uniformity of water film in an anode tube based on acoustic waves according to claim 1, characterized in that: The acoustic wave generating device (5) is a piezoelectric transducer, with multiple transducers arranged at intervals along the axial direction of the anode tube and / or arranged in a circumferential array.

5. A wet electrostatic device for promoting uniformity of water film in an anode tube based on acoustic waves, as described in claim 1, characterized in that: The anode tube (2) has a circular or regular hexagonal cross section and is made of any one of stainless steel, conductive fiberglass, conductive polypropylene, or conductive glass fiber reinforced plastic. When the anode tube (2) is made of stainless steel, an acoustic matching layer is provided on the inner wall (21) of the anode tube.

6. A wet electrostatic device for promoting uniformity of water film in an anode tube based on acoustic waves, as described in claim 5, characterized in that: The acoustic matching layer adopts a silicone rubber-tungsten powder composite system, and its acoustic impedance is the geometric average of the acoustic impedance of the pipe and the water. Its acoustic impedance can be adjusted by adjusting the volume fraction of tungsten powder. The thickness of the acoustic matching layer is λ / 4, where λ is the wavelength of the acoustic wave.

7. A wet electrostatic device for promoting uniformity of water film in an anode tube based on acoustic waves, as described in claim 1, characterized in that: The sound wave generator (5) operates at a frequency of 20kHz to 500kHz and has a power density of 0.05W / cm² to 0.1W / cm².

8. A wet electrostatic device for promoting uniformity of water film in an anode tube based on acoustic waves, as described in claim 1, characterized in that: The sound wave generator (5) operates intermittently in pulse mode with a duty cycle of 30% to 70% and a pulse period of 1s to 60s.

9. A wet electrostatic process for promoting uniformity of water film in an anode tube based on acoustic waves, characterized in that: It is achieved by any one of the wet electrostatic devices based on sound waves to promote the homogenization of the water film in the anode tube according to claims 1-8; it includes steps S1-S4; Step S1: Water is supplied to the inner wall (21) of the anode tube through the water distribution device (4) to form an initial water film flowing from top to bottom; Step S2: Under continuous water supply, the sound wave generator (5) is installed on the outer wall (22) of the anode tube in an acoustic coupling manner through the coupling layer 51. The sound wave generator (5) applies sound wave vibration to the anode tube wall (23) and generates sound flow in the water film on the inner wall (21) of the anode tube, driving the water film to overcome surface tension and spread evenly in the circumferential and / or axial directions. Step S3: Under the conditions of continuous water distribution and continuous application of acoustic vibration, negative high voltage DC current is applied to the cathode wire (3) to form a corona electric field, and electrostatic dust removal is performed on the flue gas passing through the anode tube (2); Step S4: Apply acoustic vibration intermittently in pulse mode, wherein during the pulse interval, the water film that has been uniformly spread by acoustic flow is maintained in a spread state under the combined action of liquid viscous damping.

10. A wet electrostatic process for promoting uniformity of water film in an anode tube based on acoustic waves, as described in claim 9, characterized in that: The wall thickness of the anode tube (2) is adjusted according to the acoustic characteristics of the tube, the working frequency of the sound wave and the target guided wave mode, so that the Lamb wave or quasi-Lamb wave mode is excited in the tube wall, which is 1 / 20 to 3 / 4 of the guided wave wavelength of the sound wave propagating in the tube; the coupling layer (51) material is epoxy resin-based composite material or silicone rubber.

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