Anode plate and cathode wire bonding ash coating for an electric dust precipitator and a method for producing the same

Abstract

The application discloses an electric dust collector anode plate and cathode line adhesive ash coating and a preparation method thereof, and belongs to the technical field of coatings and comprises the following raw materials: epoxy resin modified polyaniline, modified polytetrafluoroethylene emulsion, molybdenum disulfide, acetylene black, reduced graphene oxide paste, nano silicon dioxide liquid nitrile rubber, polycarboxylate dispersant, non-ionic surfactant, polyurethane associated thickener, silane coupling agent, deionized water and polyamide curing agent. The application adopts the above-mentioned electric dust collector anode plate and cathode line adhesive ash coating and the preparation method thereof, and through multi-dimensional cooperation of raw materials and processes, not only solves the core problems of serious ash deposition on the anode plate, poor rapping effect, oxidation corrosion and the like, but also realizes the transcendence of the prior art in terms of cathode line applicability, conductive performance guarantee, long-acting corrosion prevention and construction adaptability, and provides a complete solution with advanced theory and engineering feasibility for efficient and stable operation of the electric dust collector.

Description

Technical Field

[0001] This invention relates to the field of coating technology, and in particular to a coating for bonding ash and slag to the anode plate and cathode wire of an electrostatic precipitator and its preparation method. Background Technology

[0002] Electrostatic precipitators (ESPs) are core equipment for particulate matter control in coal-fired power plants, and their operating efficiency directly affects whether flue gas emissions can meet national environmental protection standards. Under ideal operating conditions, ESPs charge dust particles through high-voltage corona discharge and, under the influence of a strong electric field, capture them on the surfaces of the anode plates and cathode wires. Periodic vibration then causes the ash to fall into the ash hopper, thus achieving continuous purification of the flue gas. However, in actual operation, with the deepening of national ultra-low emission retrofitting, the large-scale application of selective catalytic reduction (SCR) denitrification systems has brought a new technical challenge: ammonia escaping during denitrification reacts with sulfur trioxide in the flue gas to form ammonium bisulfate. This substance is a viscous liquid in the operating temperature range of the ESP (typically 70-110℃), and when mixed with fly ash, it forms a highly adhesive ash that firmly adheres to the surfaces of the anode plates and cathode wires. Meanwhile, the surface of the anode plate becomes rough due to oxidation and corrosion during long-term operation. The tar-like adhesive formed by the mixture of unburned oil droplets and coal ash during ignition further worsens the adhesion of ash and slag, ultimately leading to severe ash accumulation on the electrode plate, a significant decrease in the rapping cleaning effect, violent fluctuations in the operating voltage and current of the electrostatic precipitator, and difficulty in maintaining dust removal efficiency.

[0003] To address the aforementioned issues, the industry has explored various technologies. Regarding operational adjustments, power plants often employ online ash removal measures such as optimizing the rapping cycle and increasing the flue gas temperature to above 120°C, attempting to alleviate ash adhesion on the electrode wires through pyrolysis or enhanced rapping. However, these methods have limited effectiveness and high energy consumption, failing to fundamentally solve the problem. In terms of material improvements, some studies have proposed using high-smoothness stainless steel plates to fabricate anode plates, reducing the tendency for ash adhesion; other patents disclose technical solutions for coating the cathode wire surface with conductive coatings or nano-ceramic coatings, improving anti-ash adhesion performance through coating coverage.

[0004] However, existing technologies still have significant shortcomings: on the one hand, most solutions only apply coatings locally to the cathode wires, failing to simultaneously address the problem of large-area dust accumulation on the anode plate; on the other hand, existing coating materials often struggle to balance conductivity and anti-sticking lubrication properties, and some coatings lack durability in complex flue gas environments containing ammonium bisulfate, still exhibiting problems such as coating peeling and anti-sticking failure after long-term operation. Therefore, developing a new coating material that is suitable for both the anode plate and cathode wires, possessing excellent conductivity, long-lasting anti-sticking properties, and good construction adaptability has become an urgent need for improving the efficiency of electrostatic precipitators. Summary of the Invention

[0005] The purpose of this invention is to provide an adhesive ash coating for the anode plate and cathode wire of an electrostatic precipitator and its preparation method. Through multi-dimensional synergy of raw materials and processes, it not only solves the core problems such as severe ash accumulation on the anode plate, poor rapping effect, and oxidation corrosion, but also surpasses the existing technology in terms of cathode wire applicability, conductivity assurance, long-term corrosion protection, and construction adaptability. It provides a complete solution with both theoretical advancement and engineering feasibility for the efficient and stable operation of electrostatic precipitators.

[0006] To achieve the above objectives, the present invention provides an adhesive ash coating for the anode plate and cathode wire of an electrostatic precipitator, comprising the following raw materials by weight: 20-30 parts epoxy resin modified polyaniline, 15-25 parts modified polytetrafluoroethylene emulsion, 5-8 parts molybdenum disulfide, 3-5 parts acetylene black, 5-10 parts reduced graphene oxide slurry, 2-4 parts nano silica, 2-4 parts liquid nitrile rubber, 1-2 parts polycarboxylate dispersant, 1-2 parts nonionic surfactant, 0.2-0.5 parts polyurethane associative thickener, 2-4 parts silane coupling agent, 25-35 parts deionized water, and 5-8 parts polyamide curing agent.

[0007] Preferably, the epoxy resin modified polyaniline is prepared by compounding and modifying polyaniline doped with sodium dodecylbenzenesulfonate with epoxy resin, wherein the mass ratio of polyaniline to epoxy resin is 1:2, and the amount of sodium dodecylbenzenesulfonate is 8-10% of the mass of polyaniline.

[0008] Preferably, the modified polytetrafluoroethylene emulsion is modified with carboxyl functional groups, with a carboxyl content of 1-2 wt% and a solid content of 60%.

[0009] Furthermore, the molybdenum disulfide is industrial grade, with a particle size of 500 mesh and a purity ≥98%; the acetylene black has a particle size of 30-50 nm and a specific surface area ≥200 m². 2 / g; nano silica particles with a diameter of 20-30nm; liquid nitrile rubber with epoxy end capping; polyurethane associative thickener is hydrophobic.

[0010] This invention also provides a method for preparing an adhesive ash coating for the anode plate and cathode wire of an electrostatic precipitator, comprising the following steps: S1. Add epoxy resin-modified polyaniline and liquid nitrile rubber to deionized water and stir to obtain a conductive base material; S2. The reduced graphene oxide slurry, acetylene black, molybdenum disulfide, nano silica, polycarboxylate dispersant, and silane coupling agent are placed in a dispersion container, and the filler dispersion is obtained by a process of ultrasonic dispersion and mechanical stirring. S3. Mix the conductive base material obtained in S1 with the filler dispersion obtained in S2, then add a nonionic surfactant and a polyurethane associative thickener, and stir to obtain slurry A. S4. Add modified polytetrafluoroethylene emulsion to slurry A obtained in S3, stir, then add polyamide curing agent, and stir to obtain coating slurry; S5. The surfaces of the anode plate and cathode wire of the electrostatic precipitator are sandblasted. The coating slurry prepared in S4 is sprayed onto the sandblasted anode plate and the sandblasted cathode wire respectively to obtain the sprayed anode plate and the sprayed cathode wire. The sprayed anode plate and the sprayed cathode wire are cured to obtain an adhesive ash coating on the surface of the anode plate and the cathode wire.

[0011] Preferably, in S1, the stirring speed is 3000-4000 r / min, and the stirring time is 20-30 min.

[0012] Preferably, in S2, the ultrasonic dispersion power is 300-350W, the stirring speed is 1000-2000r / min, and the stirring time is 20-30min.

[0013] Preferably, in S3, the stirring speed is 1000-1500 r / min and the stirring time is 10-20 min.

[0014] Preferably, in S4, after adding the modified polytetrafluoroethylene emulsion, the stirring speed is 400-600 r / min and the stirring time is 10-15 min; after adding the polyamide curing agent, the stirring speed is 500-800 r / min and the stirring time is 5-10 min.

[0015] Preferably, in S5, the surface of the anode plate and cathode wire after sandblasting reaches Sa2.5 level cleanliness, the surface roughness Rz is 40-80μm, and the sandblasting is completed within 4 hours; After sandblasting, the anode plate is coated with high-pressure airless spraying at a pressure of 15-20 MPa and a distance of 150-200 mm. Two coats are applied using a cross-spraying method. The cathode wire after sandblasting is coated with air at a pressure of 0.3-0.5 MPa.

[0016] Preferably, in S5, the curing method includes either baking curing or oven curing; The baking and curing temperature is 60-80℃, and hot air baking is carried out for 4 hours. The oven curing process involves first holding the oven at 60°C for 1 hour, then raising the temperature to 90°C and holding it for 2 hours, and finally allowing it to cool naturally to room temperature.

[0017] Therefore, the present invention, employing the above-mentioned method for preparing an adhesive ash coating for an anode plate and cathode wire of an electrostatic precipitator, has the following beneficial effects: (1) Through the synergistic design of raw materials and processes, a comprehensive leap in coating performance has been achieved. At the raw material level, epoxy resin modified polyaniline constructs a conductive and anti-corrosion skeleton; molybdenum disulfide and carboxyl-modified polytetrafluoroethylene form a dual anti-sticking mechanism of bulk lubrication and surface non-sticking, which synergistically solves the adhesion of ash and slag; reduced graphene oxide and acetylene black construct a three-dimensional conductive network, which, together with silane coupling agent and dispersant, achieves stable dispersion; liquid nitrile rubber and nano silica synergistically toughen and enhance the coating, improving its vibration resistance; polyurethane thickener and surfactant give the coating excellent storage stability and prevent moisture absorption.

[0018] (2) At the process level, the sandblasting pretreatment strictly limits the time window to ensure adhesion; the ultrasonic-stirring combination simultaneously disperses the filler and completes the interface modification; the step-by-step mixing and post-addition of PTFE ensure the maximum function of the components; the differentiated coating of the anode and cathode takes into account both anodic protection and cathodic discharge; the curing process is flexibly adapted to workshop prefabrication and on-site maintenance. Each link is closely connected to achieve long-term anti-sticking, electrical stability, corrosion resistance and durability, and engineering applicability.

[0019] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0020] Figure 1 This is a flowchart of the preparation process of an example 1 of the present invention, which describes an adhesive ash coating for an anode plate and cathode wire of an electrostatic precipitator and its preparation method. Figure 2 These are surface resistivity comparison diagrams of Examples 1-3 and Comparative Examples 1-5 of the present invention regarding the bonding ash slag coating for the anode plate and cathode wire of an electrostatic precipitator and its preparation method. Figure 3 This is a comparison chart of the vibration residue rate of Examples 1-3 and Comparative Examples 1-5 of the present invention, which describes the bonding ash coating for the anode plate and cathode wire of an electrostatic precipitator and its preparation method. Detailed Implementation

[0021] This invention provides a coating for bonding ash residue to the anode plate and cathode wire of an electrostatic precipitator, comprising the following raw materials by weight: 20-30 parts epoxy resin modified polyaniline, 15-25 parts modified polytetrafluoroethylene emulsion, 5-8 parts molybdenum disulfide, 3-5 parts acetylene black, 5-10 parts reduced graphene oxide slurry, 2-4 parts nano silica, 2-4 parts liquid nitrile rubber, 1-2 parts polycarboxylate dispersant, 1-2 parts nonionic surfactant, 0.2-0.5 parts polyurethane associative thickener, 2-4 parts silane coupling agent, 25-35 parts deionized water, and 5-8 parts polyamide curing agent.

[0022] In this invention, epoxy resin modified polyaniline is prepared by compounding and modifying polyaniline doped with sodium dodecylbenzenesulfonate with epoxy resin, wherein the mass ratio of polyaniline to epoxy resin is 1:2, and the amount of sodium dodecylbenzenesulfonate is 8-10% of the mass of polyaniline.

[0023] In this invention, the modified polytetrafluoroethylene emulsion is modified with carboxyl functional groups, the carboxyl content is 1-2 wt%, and the solid content is 60%.

[0024] Furthermore, the molybdenum disulfide is industrial grade, with a particle size of 500 mesh and a purity of ≥98%; the acetylene black has a particle size of 30-50 nm and a specific surface area of ​​≥200 m² / g; the nano silica has a particle size of 20-30 nm; the liquid nitrile rubber is epoxy-terminated; and the polyurethane associative thickener is hydrophobic.

[0025] Epoxy-modified polyaniline combines the conductive and corrosion-resistant properties of polyaniline with the high adhesion of epoxy resin, providing a solid conductive framework and active passivation protection for the coating. Molybdenum disulfide, as a layered solid lubricant, forms a sliding interface in the bulk phase of the coating, significantly reducing the friction coefficient between the ash and the coating. Meanwhile, the carboxyl-modified polytetrafluoroethylene emulsion utilizes its extremely low surface energy to accumulate on the surface of the coating, forming an interface layer similar to a "non-stick pan". The two form a gradient distribution of bulk lubrication and surface non-stick in space, and in time, they form a relay cooperation of initial anti-adhesion and easy detachment by rapping, fundamentally solving the adhesion problem of sticky ash of ammonium bisulfate. The two-dimensional sheet-zero-dimensional particle three-dimensional conductive network constructed by reduced graphene oxide and acetylene black is far superior to the performance of a single conductive filler. Furthermore, through the synergistic effect of silane coupling agent KH560 and polycarboxylate dispersant, the nanofiller is ensured to be uniformly dispersed in the system and achieve a strong interfacial bond with the resin matrix. Liquid nitrile rubber and epoxy resin modified polyaniline form a semi-interpenetrating network structure, which significantly improves the toughness and thermal stress resistance of the coating while ensuring conductivity. Combined with the physical filling effect of nano silica, the hardness of the coating is improved. The combination of polyurethane associative thickener and nonionic surfactant OP-10 not only endows the coating with excellent thixotropy and storage stability (no separation for 6 months), but also avoids the problem of coating dampness and stickiness caused by residual hydrophilic groups in traditional cellulose thickeners, ensuring the long-term performance of PTFE's low surface energy properties.

[0026] This invention also provides a method for preparing an adhesive ash coating for the anode plate and cathode wire of an electrostatic precipitator, comprising the following steps: S1. Add epoxy resin-modified polyaniline and liquid nitrile rubber to deionized water and stir to obtain a conductive base material; S2. The reduced graphene oxide slurry, acetylene black, molybdenum disulfide, nano silica, polycarboxylate dispersant, and silane coupling agent are placed in a dispersion container, and the filler dispersion is obtained by a process of ultrasonic dispersion and mechanical stirring. A combined ultrasonic dispersion and mechanical stirring process was employed to simultaneously disperse reduced graphene oxide, acetylene black, molybdenum disulfide, nano-silica, polycarboxylate dispersant, and silane coupling agent KH560 in a single process. The cavitation effect of ultrasound allowed rGO to be fully exfoliated into monolayers, while the shear force of stirring ensured uniform interpenetration of the components. Simultaneously, KH560 underwent a hydrolytic condensation reaction with the filler surface during dispersion, achieving interface modification. This avoided secondary agglomeration caused by the traditional process of dispersion followed by coupling. This synergistic design optimized the integrity of the conductive network and the interfacial bonding strength.

[0027] S3. Mix the conductive base material obtained in S1 with the filler dispersion obtained in S2, then add a nonionic surfactant and a polyurethane associative thickener, and stir to obtain slurry A. The conductive base material and filler dispersion were prepared in steps and then combined to ensure sufficient premixing of liquid nitrile rubber and epoxy resin modified polyaniline, avoiding interference of toughening agent on subsequent filler dispersion. The modified polytetrafluoroethylene emulsion was added in the final stage with low-speed short-time stirring, which ensured its uniform distribution in the system and prevented demulsification caused by excessive shearing. This allowed PTFE to exist stably in the bulk phase and to migrate appropriately to the surface during film formation to play a non-stick role.

[0028] S4. Add modified polytetrafluoroethylene emulsion to slurry A obtained in S3, stir, then add polyamide curing agent, and stir to obtain coating slurry; S5. The surfaces of the anode plate and cathode wire of the electrostatic precipitator are sandblasted. The coating slurry prepared in S4 is sprayed onto the sandblasted anode plate and the sandblasted cathode wire respectively to obtain the sprayed anode plate and the sprayed cathode wire. The sprayed anode plate and the sprayed cathode wire are cured to obtain an adhesive ash coating on the surface of the anode plate and the cathode wire.

[0029] In this invention, in step S1, the stirring speed is 3000-4000 r / min, and the stirring time is 20-30 min.

[0030] In this invention, in S2, the ultrasonic dispersion power is 300-350W, the stirring speed is 1000-2000r / min, and the stirring time is 20-30min.

[0031] In this invention, in step S3, the stirring speed is 1000-1500 r / min and the stirring time is 10-20 min.

[0032] In this invention, in step S4, after adding the modified polytetrafluoroethylene emulsion, the stirring speed is 400-600 r / min and the stirring is carried out for 10-15 min. After adding the polyamide curing agent, the stirring speed is 500-800 r / min and the stirring is carried out for 5-10 min.

[0033] In this invention, in S5, the surface of the anode plate and cathode wire after sandblasting reaches Sa2.5 level cleanliness, and the surface roughness Rz is 40-80μm. The sandblasting is completed within 4 hours. After sandblasting, the anode plate is coated with high-pressure airless spraying at a pressure of 15-20 MPa and a distance of 150-200 mm. Two coats are applied using a cross-spraying method. The cathode wire after sandblasting is coated with air at a pressure of 0.3-0.5 MPa.

[0034] To address the different functional requirements of the anode plate and cathode wire, differentiated coating processes are designed: the anode plate uses high-pressure airless spraying to achieve a thick coating of 80-100μm to provide long-term protection; the cathode wire uses air spraying or dip coating to achieve a thin coating of 30-50μm, and a local blank with a diameter of ≤5mm is left at the discharge tip using heat-resistant masking tape to ensure that the corona discharge intensity is not affected.

[0035] Sandblasting pretreatment enables the substrate to achieve a cleanliness level of Sa2.5 and a suitable roughness of 40-80μm, providing a dual basis for mechanical anchoring and chemical bonding of the coating. At the same time, the coating is strictly limited to be completed within 4 hours after sandblasting to effectively prevent secondary oxidation.

[0036] In this invention, in step S5, the curing method includes either baking curing or oven curing. The baking and curing temperature is 60-80℃, and hot air baking is carried out for 4 hours. The oven curing process involves first holding the oven at 60°C for 1 hour, then raising the temperature to 90°C and holding it for 2 hours, and finally allowing it to cool naturally to room temperature.

[0037] The curing process is flexibly adapted to the construction scenario. The workshop prefabrication uses a stepped oven with a temperature of 60℃ / 1h + 90℃ / 2h for curing, which ensures that the coating is fully cross-linked and achieves optimal density. On-site body spraying uses hot air baking at 60-80℃ for 4h, which perfectly matches the 3-5 day maintenance period of the power plant. After curing, the coating performance is comparable to that of the workshop prefabrication, which completely solves the engineering problem that large equipment cannot be put into the oven.

[0038] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention should be considered equivalent substitutions and are included within the protection scope of the present invention. Furthermore, it should be understood that after reading the contents of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims and are all within the protection scope of the present invention.

[0039] In this document, the term "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The term "embodiment" appearing in various places throughout the specification does not necessarily refer to the same embodiment, nor does it specifically limit its independence or connection with other embodiments. In principle, in this application, as long as there are no technical contradictions or conflicts, the technical features mentioned in each embodiment can be combined in any way to form corresponding implementable technical solutions.

[0040] Unless otherwise defined, the technical terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the use of related terms herein is merely for the purpose of describing particular embodiments and is not intended to limit this application.

[0041] In this invention, unless otherwise specified, all other test materials and instruments are conventional test materials in the field and can be purchased through commercial channels.

[0042] Example 1 This invention provides a coating for bonding ash residue to the anode plate and cathode wire of an electrostatic precipitator, comprising the following raw materials by weight: 25 parts epoxy resin modified polyaniline, 20 parts modified polytetrafluoroethylene emulsion, 6 parts molybdenum disulfide, 4 parts acetylene black, 8 parts reduced graphene oxide slurry, 3 parts nano silica, 3 parts liquid nitrile rubber, 1.5 parts polycarboxylate dispersant, 1.5 parts nonionic surfactant, 0.3 parts polyurethane associative thickener, 3 parts silane coupling agent, 28 parts deionized water, and 6 parts polyamide curing agent.

[0043] Epoxy-modified polyaniline is prepared by compounding and modifying polyaniline doped with sodium dodecylbenzenesulfonate with epoxy resin, wherein the mass ratio of polyaniline to epoxy resin is 1:2, and the amount of sodium dodecylbenzenesulfonate is 8% of the mass of polyaniline; the modified polytetrafluoroethylene emulsion has a carboxyl content of 1.5% and a solid content of 60%; the molybdenum disulfide particle size is 400 mesh; the acetylene black particle size is 40 nm; the reduced graphene oxide slurry has a solid content of 2% and a nano-silica particle size of 25 nm; the liquid nitrile rubber is epoxy-terminated; the polycarboxylate dispersant is Dispersant-5040; the nonionic surfactant is OP-10; the polyurethane associative thickener is PU-102; and the silane coupling agent is KH560.

[0044] This invention proposes a method for preparing the above-mentioned coating for bonding ash residue to the anode plate and cathode wire of an electrostatic precipitator, as described above. Figure 1 As shown, the specific steps include: S1: Add epoxy resin-modified polyaniline and liquid nitrile rubber to deionized water and stir at 3500 r / min for 20 min to obtain conductive base material.

[0045] S2: Add the reduced graphene oxide slurry, acetylene black, molybdenum disulfide, nano silica, polycarboxylate dispersant, and KH560 together, and use 300W ultrasonic dispersion and 1500r / min mechanical stirring for 20min to obtain the filler dispersion.

[0046] S3: Mix the conductive base material with the filler dispersion, add OP-10 and PU-102, stir at 1200r / min for 15min to obtain slurry A.

[0047] S4: Add modified PTFE emulsion to slurry A and stir at 500 r / min for 12 min; then add polyamide curing agent and stir at 600 r / min for 8 min to obtain coating slurry.

[0048] S5: The anode plate (Q235 steel) and cathode wire (304 stainless steel) are sandblasted to Sa2.5 grade with a radius of 50μm. Coating should be completed within 3 hours after sandblasting. The anode plate is coated using high-pressure airless spraying (18MPa pressure, 90μm dry film thickness), and the cathode wire is coated using air spraying (0.4MPa pressure, 40μm dry film thickness, with the discharge tip shielded). After coating, the surfaces are placed in an oven for curing at 60℃ for 1 hour followed by 90℃ for 2 hours, and then allowed to cool naturally.

[0049] Example 2 The only difference between this embodiment and Example 1 is that the raw material ratio is adjusted: 20 parts of epoxy resin modified polyaniline, 25 parts of modified PTFE emulsion, 5 parts of molybdenum disulfide, 3 parts of acetylene black, 10 parts of reduced graphene oxide slurry, 2 parts of nano silica, and 4 parts of liquid nitrile rubber, while the rest remain unchanged; the preparation method is the same as in Example 1.

[0050] Example 3 The only difference from Example 1 is that the raw material ratio is adjusted: epoxy resin modified polyaniline is 30 parts, modified PTFE emulsion is 15 parts, molybdenum disulfide is 8 parts, acetylene black is 5 parts, reduced graphene oxide slurry is 5 parts, nano silica is 4 parts, and liquid nitrile rubber is 2 parts, while the rest remain unchanged; the preparation method is the same as in Example 1.

[0051] Comparative Example 1 The only difference between this comparative example and Example 1 is that molybdenum disulfide is not added; all other raw materials and preparation methods are the same.

[0052] Comparative Example 2 The only difference between this comparative example and Example 1 is that no modified polytetrafluoroethylene emulsion was added; all other raw materials and preparation methods are the same.

[0053] Comparative Example 3 The only difference between this comparative example and Example 1 is that no reduced graphene oxide slurry is added, and the amount of acetylene black used is still 4 parts. All other raw materials and preparation methods are the same.

[0054] Comparative Example 4 The only difference between this comparative example and Example 1 is that in step S2, mechanical stirring at 1500 r / min for 30 min is used, and ultrasonic dispersion is not performed; all other steps are the same.

[0055] Comparative Example 5 The only difference between this comparative example and Example 1 is that in step S5, the anode plate and cathode wire are only degreased and derusted, without sandblasting, and the coating is directly sprayed on. All other steps are the same.

[0056] The performance of the samples prepared in Examples 1-3 and Comparative Examples 1-5 was tested: The coating performance was tested using the following methods: Ash accumulation thickness: The coated sample was placed in a simulated electrostatic precipitator (temperature 80℃, relative humidity 30%, simulated flue gas containing ammonium bisulfate, and an external 72kV electrostatic field) for 60 days, and the average thickness of ash on the surface was measured.

[0057] Surface resistivity: The volume resistivity of the coating surface was measured using a four-probe resistance meter.

[0058] Adhesion: Conduct cross-cut adhesion test according to GB / T 9286 standard, and rate the grade (0 is the best, 5 is the worst).

[0059] Salt spray resistance: Conduct a neutral salt spray test according to GB / T 1771 standard and record the time when rust appears.

[0060] Cathode wire discharge performance: Corona initiation voltage was tested in a simulated electric field and compared with that of an uncoated cathode wire.

[0061] The test results are shown in Table 1 and Figure 2 As shown.

[0062] Table 1. Results of dust accumulation, surface resistivity, adhesion, salt spray resistance, and cathode wire corona initiation voltage changes in Examples 1-3 and Comparative Examples 1-5.

[0063] From Table 1 and Figure 2 It can be seen that Examples 1-3 all achieved excellent comprehensive performance: dust accumulation thickness <0.05mm, surface resistance <150Ω, adhesion grade 0, and salt spray resistance >800h, proving that the technical solution of the present invention is stable and reliable within the preferred range.

[0064] In contrast, Comparative Example 1, which did not contain molybdenum disulfide, showed an increase in ash thickness to 0.4 mm, indicating that the layered lubrication effect of molybdenum disulfide is crucial for reducing ash adhesion. It forms a dual anti-sticking mechanism with the low surface energy of PTFE, and its effectiveness is significantly reduced when it is missing.

[0065] In Comparative Example 2, the lack of modified PTFE resulted in an increased dust accumulation thickness of 0.3 mm, which was better than Comparative Example 1, but still significantly higher than the example. This indicates that the low surface energy non-stick properties of PTFE are indispensable. At the same time, due to the lack of hydrogen bonding between carboxyl groups and curing agents, the salt spray resistance was slightly reduced, indicating that PTFE not only provides non-stick properties but also participates in improving interfacial compatibility.

[0066] In Comparative Example 3, the surface resistivity of the unreduced graphene oxide slurry increased to 850Ω, which is much higher than that of Examples 1-3. This indicates that the point-to-surface synergistic effect of rGO as a two-dimensional conductive framework and acetylene black failed. Acetylene black alone could not build a continuous low-resistivity network, and the conductivity decreased significantly.

[0067] In Comparative Example 4, the lack of ultrasonic dispersion in S2 resulted in a surface resistance of 560Ω and an adhesion level of 1, indicating that mechanical stirring alone cannot effectively disperse nanofillers (especially rGO), leading to discontinuous conductive networks and weak interfacial bonding; the dust accumulation thickness also increased, which is related to uneven dispersion.

[0068] Although the rGO slurry is pre-dispersed in the aqueous phase, strong π-π stacking forces and van der Waals forces still exist between the rGO sheets. The thickness of the rGO sheets is only a few nanometers, while the sheet size can reach several micrometers, with an aspect ratio as high as 1000 or more. This two-dimensional material with an ultra-high aspect ratio is extremely prone to irreversible secondary aggregation during storage and transportation.

[0069] In Comparative Example 5, the lack of a sandblasting pretreatment stage resulted in an adhesion level of 4, a salt spray resistance of only 300 hours, and a dust accumulation thickness of 0.3 mm. This demonstrates that the rough surface and clean substrate provided by sandblasting are prerequisites for strong coating adhesion, and the absence of sandblasting makes the coating prone to peeling and failure.

[0070] The rapping effect was tested on Examples 1-3 and Comparative Examples 1-5. The method for testing the rapping residue rate was as follows: 1. Place the coated sample in a simulated flue gas environment to accumulate ash for 60 days to form a stable ash layer; 2. An electromagnetic vibration table was used to simulate rapping for dust removal, with a vibration frequency of 20Hz, an amplitude of 2mm, and a rapping time of 30s. 3. Weigh the ash and slag before and after vibration, and calculate the ash and slag residue rate; Ash residue rate = (weight after vibration - net weight of sample) / (weight before vibration - net weight of sample) × 100%). The method for testing the withstand frequency of rapping is as follows: After 1000 consecutive vibrations, observe whether the coating peels off or cracks.

[0071] The test results are shown in Table 2 and Figure 3 As shown.

[0072] Table 2. Results of the vibration test

[0073] From Table 2 and Figure 3 It can be seen that the rapping residue rate of the embodiment is as low as 2-3%, which means that there is basically no ash residue on the surface of the electrode plate after rapping. The rapping residue rate of Comparative Example 1 increased to 38% due to the lack of molybdenum disulfide, and the rapping residue rate of Comparative Example 2 reached 27% due to the lack of modified polytetrafluoroethylene emulsion. The data of these two comparative examples fully demonstrate that relying solely on lubrication or non-stick alone cannot achieve the ideal rapping dust removal effect. Only the synergy of the two can achieve the excellent performance of a residue rate of less than 5%.

[0074] Due to the lack of reduced graphene oxide, Comparative Example 3 had a rapping residue rate of 16%, which was much lower than the 38% of Comparative Example 1 and without molybdenum disulfide, and the 27% of Comparative Example 2 and without modified polytetrafluoroethylene, but still significantly higher than the 2-3% of the Examples. There is a clear scientific mechanism behind this difference in data.

[0075] The function of reducing graphene oxide is to construct a three-dimensional conductive network. When this component is missing, acetylene black alone cannot form a continuous low-resistance path, causing the surface resistance of the coating to soar from 120Ω to 850Ω. This degradation in conductivity directly affects the uniformity of the electric field distribution. Under the action of a 72kV high-voltage electric field, areas with excessively high local resistance may experience charge accumulation, resulting in a slight electric field distortion. Although this distortion is not enough to trigger flashover, it will enhance the electrostatic adsorption force of the area on charged dust, making it difficult for some ash residue to fall off during rapping, thus causing the rapping residue rate to rise slightly to 16%.

[0076] This data precisely demonstrates that the conductive network is not only related to the normal operation of the electric field, but also makes an indirect contribution to anti-sticking and dust removal. It also explains why the embodiment can achieve optimal performance in both dust accumulation thickness and rapping effect.

[0077] Comparative Example 4, which did not employ ultrasonic dispersion, had a rapping residue rate of 22%, higher than Comparative Example 3's 16% but lower than Comparative Example 2's 27%. This intermediate position precisely reflects the multiple negative impacts of poor dispersion on coating performance.

[0078] Without ultrasonic dispersion, reduced graphene oxide cannot be peeled off as a single layer, but exists in the coating as multi-layer agglomerates. These agglomerates not only become breakpoints in the conductive network, but more seriously, the silane coupling agent KH560 cannot fully contact the inner filler on the agglomerate surface. This results in a large number of inorganic fillers being directly embedded in the coating without interface modification. The bonding between these unmodified agglomerates and the resin matrix relies solely on weak physical adsorption. Under repeated rapping, microcracks will first appear at the interface around the agglomerates. Although these microcracks have not yet expanded into macroscopic peeling (only slight loss of gloss after 1000 rappings), they have become weak areas where ash and slag preferentially adhere. At the same time, the unevenness of the agglomerate surface also provides a microstructure for the mechanical anchoring of ash and slag, making it more difficult to shake off the ash and slag adhering to these areas. Therefore, the rapping residue rate is significantly higher than in the example. This data strongly proves that even with a complete formulation, if the dispersion process is improper, the synergistic effect of the materials cannot be fully realized.

[0079] Comparative Example 5, which did not undergo sandblasting pretreatment, had a rapping residue rate as high as 45%, and localized peeling occurred after 1000 rapping cycles, making it the worst performing of all samples. This data thoroughly reveals the essential connection between sandblasting treatment and coating performance.

[0080] The fundamental purpose of sandblasting is twofold: first, to thoroughly remove the oxide layer and contaminants from the electrode surface, exposing the fresh metal substrate and providing a basis for chemical bonding of the coating; and second, to create a roughness of 40-80 μm on the substrate surface, significantly enhancing the coating's adhesion through mechanical anchoring. When this pretreatment is lacking, the coating is applied directly onto the existing oxide layer. Even with an excellent formulation, the adhesion will only reach level 4, meaning the bond strength between the coating and the substrate is less than 5 MPa. At this level of adhesion, the rapping force will directly act on the weak interface, causing localized lifting and peeling of the coating. The exposed substrate surface at the peeling point is rough and continuously oxidized, becoming a new core for ash and slag accumulation. Simultaneously, the surrounding coating also fails more rapidly due to loss of support, ultimately creating a vicious cycle.

[0081] The 45% rapping residue rate of Comparative Example 5 actually includes the weight loss caused by coating peeling, and not just the residue of ash and slag. This is the fundamental reason for its abnormally high value, and it also irrefutably proves the absolute necessity of sandblasting pretreatment as a prerequisite step for this technical solution.

[0082] Therefore, the present invention adopts the above-mentioned ash coating for bonding anode plates and cathode wires of electrostatic precipitators and its preparation method. Through the multi-dimensional synergy of raw materials and processes, it not only solves the core problems such as severe ash accumulation on anode plates, poor rapping effect, and oxidation corrosion, but also surpasses the existing technology in terms of cathode wire applicability, conductivity assurance, long-term corrosion protection, and construction adaptability. It provides a complete solution with both theoretical advancement and engineering feasibility for the efficient and stable operation of electrostatic precipitators.

[0083] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A coating for bonding ash and slag to the anode plate and cathode wire of an electrostatic precipitator, characterized in that: By weight, it includes the following raw materials: 20-30 parts epoxy resin modified polyaniline, 15-25 parts modified polytetrafluoroethylene emulsion, 5-8 parts molybdenum disulfide, 3-5 parts acetylene black, 5-10 parts reduced graphene oxide slurry, 2-4 parts nano silica, 2-4 parts liquid nitrile rubber, 1-2 parts polycarboxylate dispersant, 1-2 parts nonionic surfactant, 0.2-0.5 parts polyurethane associative thickener, 2-4 parts silane coupling agent, 25-35 parts deionized water, and 5-8 parts polyamide curing agent.

2. The ash coating for bonding anode plates and cathode wires in an electrostatic precipitator according to claim 1, characterized in that: Epoxy resin modified polyaniline is prepared by compounding and modifying polyaniline doped with sodium dodecylbenzenesulfonate with epoxy resin, wherein the mass ratio of polyaniline to epoxy resin is 1:2, and the amount of sodium dodecylbenzenesulfonate is 8-10% of the mass of polyaniline.

3. The ash coating for bonding anode plates and cathode wires in an electrostatic precipitator according to claim 1, characterized in that: The modified polytetrafluoroethylene emulsion is modified with carboxyl functional groups, with a carboxyl content of 1-2 wt% and a solid content of 60%.

4. A method for preparing an adhesive ash coating for the anode plate and cathode wire of an electrostatic precipitator as described in any one of claims 1-3, characterized in that: Includes the following steps: S1. Add epoxy resin-modified polyaniline and liquid nitrile rubber to deionized water and stir to obtain a conductive base material; S2. The reduced graphene oxide slurry, acetylene black, molybdenum disulfide, nano silica, polycarboxylate dispersant, and silane coupling agent are placed in a dispersion container, and the filler dispersion is obtained by a process of ultrasonic dispersion and mechanical stirring. S3. Mix the conductive base material obtained in S1 with the filler dispersion obtained in S2, then add a nonionic surfactant and a polyurethane associative thickener, and stir to obtain slurry A. S4. Add modified polytetrafluoroethylene emulsion to slurry A obtained in S3, stir, then add polyamide curing agent, and stir to obtain coating slurry; S5. The surfaces of the anode plate and cathode wire of the electrostatic precipitator are sandblasted. The coating slurry prepared in S4 is sprayed onto the sandblasted anode plate and the sandblasted cathode wire respectively to obtain the sprayed anode plate and the sprayed cathode wire. The sprayed anode plate and the sprayed cathode wire are cured to obtain an adhesive ash coating on the surface of the anode plate and the cathode wire.

5. The method for preparing an adhesive ash coating for the anode plate and cathode wire of an electrostatic precipitator according to claim 4, characterized in that: In S1, the stirring speed is 3000-4000 r / min, and the stirring time is 20-30 min.

6. The method for preparing an adhesive ash coating for the anode plate and cathode wire of an electrostatic precipitator according to claim 4, characterized in that: In S2, the ultrasonic dispersion power is 300-350W, the stirring speed is 1000-2000r / min, and the stirring time is 20-30min.

7. The method for preparing an adhesive ash coating for the anode plate and cathode wire of an electrostatic precipitator according to claim 4, characterized in that: In S3, the stirring speed is 1000-1500 r / min and the stirring time is 10-20 min.

8. The method for preparing an adhesive ash coating for the anode plate and cathode wire of an electrostatic precipitator according to claim 4, characterized in that: In S4, after adding the modified polytetrafluoroethylene emulsion, the stirring speed is 400-600 r / min and the stirring is carried out for 10-15 min. After adding the polyamide curing agent, the stirring speed is 500-800 r / min and the stirring is carried out for 5-10 min.

9. The method for preparing an adhesive ash coating for the anode plate and cathode wire of an electrostatic precipitator according to claim 4, characterized in that: In S5, the surface of the anode plate and cathode wire after sandblasting reaches Sa2.5 cleanliness level, and the surface roughness Rz is 40-80μm. The sandblasting is completed within 4 hours. After sandblasting, the anode plate is coated with high-pressure airless spraying at a pressure of 15-20 MPa and a distance of 150-200 mm. Two coats are applied using a cross-spraying method. The cathode wire after sandblasting is coated with air at a pressure of 0.3-0.5 MPa.

10. The method for preparing an adhesive ash coating for the anode plate and cathode wire of an electrostatic precipitator according to claim 4, characterized in that: In S5, the curing method includes either baking curing or oven curing; The baking and curing temperature is 60-80℃, and hot air baking is carried out for 4 hours. The oven curing process involves first holding the oven at 60°C for 1 hour, then raising the temperature to 90°C and holding it for 2 hours, and finally allowing it to cool naturally to room temperature.

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