Dust removal device for low-temperature economizer of thermal power plant

Abstract

The dust removal device for the low-temperature economizer of the thermal power plant belongs to the technical field of low-temperature economizers and comprises a low-temperature economizer shell, a low-temperature economizer body is arranged in the low-temperature economizer shell, and dust removal mechanisms are symmetrically arranged on the two sides in the low-temperature economizer shell. The dust removal mechanism comprises a first connecting plate and a second connecting plate which are symmetrically and fixedly connected into the low-temperature economizer shell, a cleaning roller is slidably connected between the first connecting plate and the second connecting plate, a first driving part is arranged at the bottom of the first connecting plate and is in transmission connection with the cleaning roller, and the cleaning roller abuts against the outer wall of the low-temperature economizer body. The first driving part drives the cleaning roller to move along the first connecting plate and the second connecting plate, the cleaning roller makes rolling contact with the outer wall of the low-temperature economizer body, and accumulated dust is physically scraped off. The double-side synchronous cleaning symmetrical design covers a more comprehensive heat exchange surface, the dust removal efficiency is improved, meanwhile, dust is continuously removed in the operation process, and the production halt loss caused by traditional vibration dust removal is avoided.

Description

Technical Field

[0001] This invention belongs to the field of low-temperature economizer technology, and particularly relates to a dust removal device for low-temperature economizers in thermal power plants. Background Technology

[0002] To achieve energy conservation and emission reduction in coal-fired power plants, a low-temperature economizer is installed before the electrostatic precipitator (ESP). In this economizer, flue gas and condensate exchange heat counter-currently, lowering the flue gas temperature to the acid dew point. The low-temperature economizer not only recovers waste heat from the flue gas for heating condensate or the primary air in the air preheater, but also, due to the reduced flue gas temperature, decreases the volumetric flow rate of the flue gas entering the ESP, increasing dust concentration and decreasing resistivity. This improves the ESP's dust removal efficiency and reduces equipment investment. The low-temperature economizer is a key piece of equipment for energy conservation and emission reduction retrofitting in coal-fired power plants. However, in some cases, the reduced flue gas volume leads to lower flue gas velocity, resulting in significant ash accumulation in the flue and economizer, ultimately severely impacting the economizer's heat exchange performance. Summary of the Invention

[0003] The purpose of this invention is to provide a dust removal device for a low-temperature economizer in a thermal power plant, so as to solve the problems existing in the prior art.

[0004] To achieve the above objectives, the present invention provides the following solution: The present invention provides a dust removal device for a low-temperature economizer in a thermal power plant, comprising a low-temperature economizer shell, a low-temperature economizer body disposed inside the low-temperature economizer shell, and dust removal mechanisms symmetrically disposed on both sides inside the low-temperature economizer shell. The dust removal mechanism includes a first connecting plate and a second connecting plate symmetrically fixed inside the low-temperature economizer shell, a cleaning roller slidably connected between the first connecting plate and the second connecting plate, a first driving part disposed at the bottom of the first connecting plate, the first driving part being drivenly connected to the cleaning roller, and the cleaning roller abutting against the outer wall of the low-temperature economizer body.

[0005] Preferably, the first connecting plate is located below the body of the low-temperature economizer, and the second connecting plate is located above the body of the low-temperature economizer. The first connecting plate is provided with a first sliding groove, and the bottom of the cleaning roller is slidably connected in the first sliding groove. The bottom of the first sliding groove is provided with a second sliding groove, and the second sliding groove communicates with the first sliding groove. The bottom of the cleaning roller is fixedly connected with a first connecting shaft, and the first connecting shaft passes through the second sliding groove and is connected to the first driving part for transmission.

[0006] Preferably, a first gear is fixedly connected to the bottom of the first connecting shaft, the first gear is connected to the first driving part for transmission, a third sliding groove is provided on the bottom surface of the first connecting plate away from the inner wall of the low temperature economizer housing, the first driving part includes a first motor slidably connected in the third sliding groove, a second gear is fixedly connected to the output shaft of the first motor, and the second gear meshes with the first gear.

[0007] Preferably, the top of the third slide groove is symmetrically provided with a first limiting groove, and the first motor is symmetrically fixed with a first protrusion on the side near the first limiting groove, and the first protrusion and the first limiting groove adjacent to it are slidably connected.

[0008] Preferably, the first chute is provided with a second limiting groove, and the bottom of the cleaning roller is provided with a first limiting ring, which is slidably connected in the second limiting groove.

[0009] Preferably, the cleaning roller is provided with a third gear, which is located above the first connecting plate. The first connecting plate is fixedly connected to a connecting seat near the top of the inner wall of the low-temperature economizer shell. The connecting seat is provided with a rack on the side near the third gear, and the third gear meshes with the rack.

[0010] Preferably, the bottom surface of the second connecting plate is provided with a fourth sliding groove, and the top of the cleaning roller is slidably connected in the fourth sliding groove.

[0011] Preferably, the fourth groove is provided with a third limiting groove, and the top surface of the cleaning roller is provided with a second limiting ring, which is slidably connected in the third limiting groove.

[0012] Preferably, the heat exchange tube surface of the low-temperature economizer body is provided with a nano-coating.

[0013] Preferably, one end of the shell of the low-temperature economizer is provided with a flow guide shroud, and the flow guide shroud is provided with a ventilation pipe.

[0014] This invention discloses the following technical advantages: A first driving unit drives a cleaning roller to move along a first connecting plate and a second connecting plate. The cleaning roller rolls into contact with the outer wall of the low-temperature economizer body, physically scraping away accumulated ash. This invention, through a symmetrical design with simultaneous cleaning on both sides, covers a more comprehensive heat exchange surface, improving ash removal efficiency. Simultaneously, continuous ash removal during operation avoids production downtime losses caused by traditional rapping ash removal. Attached Figure Description

[0015] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings:

[0016] Figure 1 This is a schematic diagram of the internal structure of the dust removal device of the present invention used in a low-temperature economizer for thermal power plants;

[0017] Figure 2 This is a schematic diagram of the external structure of the dust removal device for a low-temperature economizer in a thermal power plant according to the present invention;

[0018] Figure 3 For the present invention Figure 1 A magnified view of A is available.

[0019] In the diagram: 1. Low-temperature economizer outer shell; 2. Low-temperature economizer body; 3. First connecting plate; 4. Second connecting plate; 5. Cleaning roller; 6. First chute; 7. Second chute; 8. First connecting shaft; 9. First gear; 10. Third chute; 11. First motor; 12. Second gear; 13. First limiting groove; 14. First protrusion; 15. Second limiting groove; 16. First limiting ring; 17. Third gear; 18. Connecting seat; 19. Rack; 20. Fourth chute; 21. Third limiting groove; 22. Second limiting ring; 23. Flow guide; 24. Ventilation pipe. Detailed Implementation

[0020] Against the backdrop of energy structure transformation and increasingly stringent environmental protection requirements, thermal power plants, as the main suppliers of traditional energy, are facing the dual challenges of energy conservation and emission reduction. Low-temperature economizers, as key equipment in the boiler tail flue, improve energy efficiency through waste heat recovery, while dust removal devices are core environmental protection facilities ensuring emission compliance. The two have become closely linked in technological evolution; the application of low-temperature economizers not only changes the characteristics of flue gas but also has a profound impact on the efficiency of dust removal systems.

[0021] The technological evolution of low-temperature economizers is closely related to the energy efficiency improvement needs of thermal power plants. Early thermal power plants recovered waste heat by installing economizers at the boiler tail, but the application of traditional economizers was limited by space constraints and economic constraints. The emergence of low-temperature economizers has broken through this bottleneck. They adopt a cross-flow heat exchange structure with indirect walls, achieving heat exchange through three stages: convective heat transfer between the hot fluid and the wall, heat conduction through the wall, and convective heat transfer between the cold fluid and the wall. Innovative designs such as wide-channel self-cleaning plate heat exchangers, with corrugated channels forcibly agitating the flow to improve the heat transfer coefficient, combined with heat-resistant and pressure-resistant materials, have demonstrated technical advantages such as no increase in resistance and no surface corrosion in the application of the 660MW unit at Jiaxing Power Plant.

[0022] The thermodynamic characteristics of the low-temperature economizer determine its operating parameters. When the flue gas temperature drops from 120-130℃ to below the acid dew point, water vapor in the flue gas condenses and releases latent heat, and the increased condensate temperature feeds back into the thermal system. This temperature control capability directly affects subsequent dust removal processes: for every 10℃ decrease in flue gas temperature, the flue gas volume decreases by approximately 2%-3%, directly altering the inlet conditions of the dust collector. The coordinated layout of the low-temperature economizer and dust removal device is gradually becoming the standard configuration for flue gas treatment systems in modern thermal power plants.

[0023] Dust removal devices, as key equipment in the end-of-pipe treatment of thermal power plants, have evolved in a way that reflects increasingly stringent environmental protection requirements. Electrostatic precipitators (ESPs) use positive and negative electrodes to create a high-voltage electric field, ionizing dust particles and causing them to deposit on the collecting electrode under the influence of the electric field. This technology has undergone multiple iterations, evolving from single-zone electric fields to advanced forms such as moving electrodes and pulsed power supply, significantly improving the collection efficiency for submicron particles. Baghouse dust collectors, on the other hand, rely on filter media filtration. The application of PTFE-coated filter media enables filtration accuracy to reach the 0.1μm level, demonstrating excellent performance in flue gas treatment after wet desulfurization.

[0024] The performance evaluation indicators of dust collection devices cover multiple dimensions such as efficiency, resistance, and reliability. The pressure loss of an electrostatic precipitator is typically below 300 Pa, while baghouse dust collectors, due to the higher resistance of their filter media, require pulse-jet cleaning to maintain operation. Equipment selection must comprehensively consider flue gas characteristics; parameters such as fly ash resistivity and particle size distribution directly affect the efficiency of electrostatic precipitators, while flue gas humidity and temperature determine the selection of filter media materials for baghouse dust collectors.

[0025] The impact of low-temperature economizers on dust removal devices is reflected in both changes in thermodynamic parameters and flue gas properties. Lower exhaust gas temperature leads to a reduction in flue gas volume, directly decreasing the air volume handled by the dust collector, and consequently reducing the electric field velocity or filtration velocity. Taking a 600MW unit as an example, a 15℃ reduction in exhaust gas temperature can reduce the flue gas volume by approximately 4.5%, and the electric field velocity drops from 1.0 m / s to 0.95 m / s, effectively extending the residence time of dust particles in the electric field. Lower temperature also alters the resistivity of fly ash; when the temperature drops from 150℃ to 90℃, the resistivity of typical fly ash can decrease by 1-2 orders of magnitude, significantly improving the electrostatic precipitator's charging performance.

[0026] Flue gas temperature control improves dust removal efficiency. Low-temperature economizers lower the flue gas temperature below the acid dew point, causing SO3 to condense into sulfuric acid mist, which adheres to the fly ash surface and enhances conductivity. Experimental data shows that in the 90-100℃ temperature range, the PM2.5 collection efficiency of electrostatic precipitators can be improved by 15%-20%. Simultaneously, the reduced flue gas volume leads to an increase in inlet concentration, creating a "concentration effect," which manifests as an increase in space charge density within the electrostatic precipitator, further enhancing the collection effect.

[0027] Ash accumulation control is a key technology for coordinated operation. The low-temperature economizer employs an optimized flow channel design, coupled with steam soot blowing or ultrasonic cleaning devices, to ensure the cleanliness of the heat exchange surface. Operational data from a power plant shows that, using a design flow velocity of 10 m / s combined with dual-frequency ultrasonic cleaning, the heat exchange efficiency remained at 92% of its initial value after 3600 hours of continuous operation. A guide vane is installed in the inlet flue of the dust removal device to ensure a flue gas flow uniformity of over 90%, preventing localized high-speed scouring that could lead to ash accumulation.

[0028] The increasingly complex characteristics of flue gas from thermal power plants pose new challenges to dust removal technology. After wet desulfurization, the moisture content of the flue gas reaches 10%-15%, forming viscous aerosols, posing a risk of back corona to traditional electrostatic precipitators. The combined technology of a low-temperature economizer and a wet electrostatic precipitator (WESP) has emerged to address this issue. By controlling the flue gas temperature to maintain an unsaturated state, and combined with the fine particulate capture capability of the WESP, PM2.5 emission concentrations can be reduced to below 5 mg / m³.

[0029] Materials science and flow field simulation technology are driving innovation in dust collection devices. Electrode systems made of C276 alloy or fiberglass offer corrosion resistance and a lifespan of over 10 years in acidic flue gas environments. Computational fluid dynamics (CFD) simulations optimize the internal flow field of the dust collector, reducing the velocity deviation coefficient in the electric field region to less than 15%, significantly improving dust collection uniformity.

[0030] The deep integration of cryogenic economizers and dust removal devices has become a development trend. In ultra-low emission retrofitting, cryogenic economizers and cryogenic electrostatic precipitators (LEPs) work together to achieve dual optimization of energy saving and dust removal through precise flue gas temperature control. The application of intelligent control technology enables the dust removal device to adjust parameters such as voltage and rapping cycle in real time according to flue gas parameters, reducing system energy consumption by 15%-20%.

[0031] New materials and processes continue to push technological boundaries. The application of ceramic fiber filter tubes in baghouse dust collectors enables filtration temperatures up to 300℃, solving the challenge of high-temperature flue gas treatment. Nano-coating technology enhances the corrosion resistance of electrodes, extending their service life by more than two times in flue gas environments after wet desulfurization.

[0032] The synergy between low-temperature economizers and dust removal devices embodies the system integration characteristics of energy-saving and environmental protection technologies in thermal power plants. In the technology chain from waste heat recovery to particulate matter control, parameter matching and operating condition optimization between equipment are crucial. With continuous advancements in materials science, flow field control, and intelligent algorithms, dust removal devices will develop towards greater efficiency, reliability, and intelligence, providing technical support for the green transformation of thermal power plants.

[0033] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0035] Reference Figures 1-3 As shown, this embodiment provides a dust removal device for a low-temperature economizer in a thermal power plant, including a low-temperature economizer shell 1, a low-temperature economizer body 2 inside the low-temperature economizer shell 1, and dust removal mechanisms symmetrically arranged on both sides inside the low-temperature economizer shell 1. The dust removal mechanism includes a first connecting plate 3 and a second connecting plate 4 symmetrically fixed inside the low-temperature economizer shell 1. A cleaning roller 5 is slidably connected between the first connecting plate 3 and the second connecting plate 4. A first driving part is provided at the bottom of the first connecting plate 3. The first driving part is connected to the cleaning roller 5 in a transmission manner. The cleaning roller 5 abuts against the outer wall of the low-temperature economizer body 2.

[0036] The cleaning roller 5 is driven by the first drive unit to move along the first connecting plate 3 and the second connecting plate 4. The cleaning roller 5 rolls and contacts the outer wall of the low-temperature economizer body 2, physically scraping away the accumulated ash. This invention improves the ash removal efficiency by covering a more comprehensive heat exchange surface through a symmetrical design of simultaneous cleaning on both sides. At the same time, it continuously removes ash during operation, avoiding the production losses caused by traditional rapping ash removal.

[0037] In a further optimized design, the first connecting plate 3 is located below the low-temperature economizer body 2, and the second connecting plate 4 is located above the low-temperature economizer body 2. The first connecting plate 3 is provided with a first sliding groove 6, and the bottom of the cleaning roller 5 is slidably connected in the first sliding groove 6. The bottom of the first sliding groove 6 is provided with a second sliding groove 7, which communicates with the first sliding groove 6. The bottom of the cleaning roller 5 is fixedly connected with a first connecting shaft 8, which passes through the second sliding groove 7 and is connected to the first drive unit for transmission.

[0038] In a further optimized design, a first gear 9 is fixedly connected to the bottom of the first connecting shaft 8. The first gear 9 is connected to the first drive unit for transmission. A third slide groove 10 is provided on the bottom surface of the first connecting plate 3 away from the inner wall of the low-temperature economizer housing 1. The first drive unit includes a first motor 11 that is slidably connected in the third slide groove 10. A second gear 12 is fixedly connected to the output shaft of the first motor 11. The second gear 12 meshes with the first gear 9.

[0039] The first motor 11 drives the second gear 12 to rotate, the second gear 12 drives the first gear 9 to rotate, and then drives the first connecting shaft 8 to rotate. The first connecting shaft 8 drives the cleaning roller 5 to slide along the first slide groove 6. The slide groove limit ensures that the cleaning roller 5 always fits the curved surface of the heat exchange tube, and the dust is cleaned without dead corners.

[0040] In a further optimized design, a first limiting groove 13 is symmetrically provided at the top of the third slide groove 10, and a first protrusion 14 is symmetrically fixed to the side of the first motor 11 near the first limiting groove 13. The first protrusion 14 and the first limiting groove 13 adjacent to it are slidably connected.

[0041] The rotation of the first motor 11 is limited by setting the first protrusion 14 and the first limiting groove 13.

[0042] In a further optimized design, a second limiting groove 15 is provided in the first chute 6, and a first limiting ring 16 is provided at the bottom of the cleaning roller 5. The first limiting ring 16 is slidably connected in the second limiting groove 15.

[0043] The first limiting ring 16 rolls within the second limiting groove 15, constraining the cleaning roller 5 to only perform axial translation.

[0044] In a further optimized design, a third gear 17 is provided on the cleaning roller 5. The third gear 17 is located above the first connecting plate 3. A connecting seat 18 is fixedly connected to the top of the first connecting plate 3 near the inner wall of the low-temperature economizer shell 1. A rack 19 is provided on the side of the connecting seat 18 near the third gear 17. The third gear 17 meshes with the rack 19.

[0045] When the cleaning roller 5 moves, the third gear 17 meshes with the rack 19, enhancing the circumferential driving force.

[0046] In a further optimized design, the bottom surface of the second connecting plate 4 is provided with a fourth sliding groove 20, and the top of the cleaning roller 5 is slidably connected within the fourth sliding groove 20.

[0047] To further optimize the design, a third limiting groove 21 is provided in the fourth chute 20, and a second limiting ring 22 is provided on the top surface of the cleaning roller 5. The second limiting ring 22 is slidably connected in the third limiting groove 21.

[0048] The second limiting ring 22 rolls within the third limiting groove 21, constraining the cleaning roller 5 to only perform axial translation.

[0049] To further optimize the design, the heat exchange tubes of the low-temperature economizer body 2 are coated with a nano-coating.

[0050] The surface of the heat exchange tube is coated with an Al2O3-TiO2 nanocomposite coating (50μm thick) to improve the heat exchange tube's resistance to acid corrosion.

[0051] To further optimize the design, a flow guide shroud 23 is installed at one end of the shell 1 of the low-temperature economizer, and a ventilation pipe 24 is installed on the flow guide shroud 23. The flow guide shroud 23 rectifies the flue gas and distributes it evenly to the dust removal area; the ventilation pipe 24 balances the pressure difference between the inside and outside.

[0052] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0053] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A dust removal device for a low-temperature economizer in a thermal power plant, characterized in that: The device includes a low-temperature economizer shell (1), a low-temperature economizer body (2) inside the low-temperature economizer shell (1), and dust removal mechanisms symmetrically arranged on both sides inside the low-temperature economizer shell (1). The dust removal mechanism includes a first connecting plate (3) and a second connecting plate (4) symmetrically fixed inside the low-temperature economizer shell (1). A cleaning roller (5) is slidably connected between the first connecting plate (3) and the second connecting plate (4). A first driving part is provided at the bottom of the first connecting plate (3). The first driving part is connected to the cleaning roller (5) in a transmission manner. The cleaning roller (5) abuts against the outer wall of the low-temperature economizer body (2).

2. The dust removal device for a low-temperature economizer in a thermal power plant according to claim 1, characterized in that: The first connecting plate (3) is located below the body (2) of the low-temperature economizer, and the second connecting plate (4) is located above the body (2) of the low-temperature economizer. The first connecting plate (3) is provided with a first sliding groove (6). The bottom of the cleaning roller (5) is slidably connected in the first sliding groove (6). The bottom of the first sliding groove (6) is provided with a second sliding groove (7). The second sliding groove (7) is connected to the first sliding groove (6). The bottom of the cleaning roller (5) is fixedly connected with a first connecting shaft (8). The first connecting shaft (8) passes through the second sliding groove (7) and is connected to the first driving part for transmission.

3. The dust removal device for a low-temperature economizer in a thermal power plant according to claim 2, characterized in that: The bottom of the first connecting shaft (8) is fixedly connected to a first gear (9), which is connected to the first driving unit. The bottom surface of the first connecting plate (3) is provided with a third slide groove (10) on the side away from the inner wall of the low temperature economizer shell (1). The first driving unit includes a first motor (11) slidably connected in the third slide groove (10). The output shaft of the first motor (11) is fixedly connected to a second gear (12), which meshes with the first gear (9).

4. The dust removal device for a low-temperature economizer in a thermal power plant according to claim 3, characterized in that: The top of the third slide groove (10) is symmetrically provided with a first limiting groove (13), and the first motor (11) is symmetrically fixed with a first protrusion (14) on the side near the first limiting groove (13). The first protrusion (14) and the first limiting groove (13) adjacent to it are slidably connected.

5. The dust removal device for a low-temperature economizer in a thermal power plant according to claim 2, characterized in that: The first chute (6) is provided with a second limiting groove (15), and the bottom of the cleaning roller (5) is provided with a first limiting ring (16), which is slidably connected in the second limiting groove (15).

6. The dust removal device for a low-temperature economizer in a thermal power plant according to claim 1, characterized in that: The cleaning roller (5) is provided with a third gear (17), which is located above the first connecting plate (3). The first connecting plate (3) is fixedly connected to the top of the inner wall of the low temperature economizer shell (1). The connecting plate (18) is provided with a rack (19) on the side of the connecting plate (18) near the third gear (17). The third gear (17) meshes with the rack (19).

7. The dust removal device for a low-temperature economizer in a thermal power plant according to claim 1, characterized in that: The bottom surface of the second connecting plate (4) is provided with a fourth groove (20), and the top of the cleaning roller (5) is slidably connected in the fourth groove (20).

8. The dust removal device for a low-temperature economizer in a thermal power plant according to claim 7, characterized in that: The fourth slide groove (20) is provided with a third limiting groove (21), and the top surface of the cleaning roller (5) is provided with a second limiting ring (22), which is slidably connected in the third limiting groove (21).

9. The dust removal device for a low-temperature economizer in a thermal power plant according to claim 1, characterized in that: The heat exchange tube surface of the low-temperature economizer body (2) is provided with a nano-coating.

10. The dust removal device for a low-temperature economizer in a thermal power plant according to claim 1, characterized in that: The low-temperature economizer shell (1) is provided with a flow guide shroud (23) at one end, and a ventilation pipe (24) is provided on the flow guide shroud (23).

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