Energy-saving boiler anti-deviation coal economizer auxiliary device

Abstract

The application discloses an energy-saving boiler anti-deviation economizer auxiliary device and relates to the technical field of energy-saving boiler waste heat recovery equipment. The energy-saving boiler anti-deviation economizer auxiliary device comprises an economizer body, a flue gas flow uniformizing device arranged in series along the flue gas flow direction at the flue gas inlet side of the economizer body, and a protective self-cleaning device arranged at the heat exchange tube bundle of the economizer body; the protective self-cleaning device comprises a movable mesh cylinder coaxially sleeved outside each heat exchange tube bundle, a driving assembly, a fin type supporting positioning ring and a dust cleaning and collecting assembly; the movable mesh cylinder adopts a local convex non-circular cross-section structure with elastic deformation capacity, and a plurality of arc convex parts are arranged on the outer wall of the movable mesh cylinder in the circumferential direction; a flow gap is left between the non-convex regions of adjacent movable mesh cylinders; an annular gap is left between the movable mesh cylinder and the outer wall of the heat exchange tube bundle; the device can efficiently shake off stubborn fly ash embedded in the surface and mesh holes of the movable mesh cylinder and accumulated on the surface of the movable mesh cylinder, and can guarantee the continuous and stable work of the composite dust cleaning system.

Description

Technical Field

[0001] This invention relates to the field of boiler waste heat recovery and energy-saving equipment technology, specifically an auxiliary device for an energy-saving boiler anti-deviation economizer. Background Technology

[0002] The economizer is the core equipment for waste heat recovery at the boiler tail end, and its operating efficiency directly affects the overall heat energy consumption of the boiler. Existing boiler economizers commonly suffer from flue gas flow deviation: due to factors such as flue bends, cross-sectional changes, and boundary layer effects, the velocity distribution of flue gas entering the heat exchange tube bundle is extremely uneven, with the flue gas velocity in the center or on one side far exceeding the design value, while the velocity in the wall area is too low. Flow deviation leads to two core problems: First, heat exchange efficiency decreases and energy consumption increases: insufficient heat exchange in the low flow rate zone creates a heat exchange blind zone, leading to increased flue gas temperature, reduced boiler thermal efficiency, and waste of thermal energy. Second, equipment wear is aggravated: the cutting and wear of fly ash particles on the tube bundle is greatly enhanced in the high flow velocity zone, and the local wear rate is many times that of the uniform flow field, which can easily lead to tube bundle leakage; at the same time, the local low temperature dew point corrosion caused by the flow deviation will also shorten the equipment life.

[0003] To reduce fly ash wear on the tube bundles, a fixed protective mesh is installed on the outside of the tube bundles to intercept large-diameter fly ash particles and reduce cutting wear. However, the fixed mesh is a stationary obstacle, and after long-term operation, large fly ash particles will become stuck in the mesh or deposit on the windward side of the mesh, gradually clogging the mesh and causing a continuous increase in flue gas flow resistance and a decrease in heat exchange efficiency. At the same time, the fixed mesh relies solely on pulse steam purging for cleaning, which has limited effectiveness in cleaning stubborn ash embedded in the mesh and with strong adhesion. The cleaning is incomplete, requiring frequent start-ups and shutdowns of the soot blowing system, resulting in wasted steam heat energy.

[0004] Therefore, there is an urgent need to develop an auxiliary device for an energy-saving boiler economizer to prevent eccentricity and solve the aforementioned problems. Summary of the Invention

[0005] The purpose of this invention is to provide an auxiliary device for an energy-saving boiler economizer to prevent eccentricity and solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: an auxiliary device for an economizer to prevent flow deviation in an energy-saving boiler, comprising an economizer body and a flue gas flow equalization device arranged in series along the flue gas flow direction on the flue gas inlet side of the economizer body, and a protective self-cleaning device correspondingly provided at the heat exchange tube bundle of the economizer body. The protective self-cleaning device includes a movable mesh cylinder coaxially sleeved on the outside of each heat exchange tube bundle, a drive assembly, a finned support positioning ring, and a cleaning and dust collection assembly. The movable mesh cylinder adopts a partially convex non-circular cross-section structure with elastic deformation capability, and the outer wall of the movable mesh cylinder is provided with several arc-shaped convex parts in the circumferential direction; A flow gap is left between the non-protruding areas of adjacent movable mesh cylinders; an annular gap is left between the movable mesh cylinder and the outer wall of the heat exchange tube bundle, and it is coaxially aligned by a number of support positioning rings arranged at intervals along the axial direction. The driving component is used to drive each movable screen cylinder in the same tube bank to rotate synchronously at low speed around the heat exchange tube bundle, so that the arc-shaped outward protrusions of adjacent movable screen cylinders periodically and momentarily touch each other, causing the movable screen cylinders to produce radial elastic deformation and rebound, and mechanically vibrating to shake off the fly ash adhering to the surface of the movable screen cylinders and inside the mesh. The dust removal and collection component is linked to the rotation of the movable screen cylinder, and is used to blow away and collect the dust accumulated on the surface of the movable screen cylinder.

[0007] As a preferred technical solution of the present invention, the flue gas flow equalization device includes a flue gas pipeline, wherein a flow guiding unit and a flow rectifying unit are sequentially configured from upstream to downstream of the flue gas to correct the flue gas flow deviation step by step in order to output a uniform flow field. The flow guiding unit is composed of streamlined flow guiding plates arranged in parallel along the width direction of the flue gas pipeline. The flow-facing surface of the flow guiding plate adopts a streamlined curved surface structure with a rounded transition. The inclination angle of the flow-facing surface of the flow guiding plate gradually changes from the inlet end to the outlet end along the flue gas flow direction. The rectifier unit adopts a honeycomb structure, which is formed by orthogonally splicing horizontal and vertical grid plates to form a regular hexagonal honeycomb rectifier cavity; the front edge of the grid plate is rounded and blunted.

[0008] As a preferred embodiment of the present invention, the movable mesh cylinder includes a wedge-wire welded mesh cylinder, wherein the mesh of the wedge-wire welded mesh cylinder adopts a trapezoidal cross-sectional structure with a narrow frontal surface and a wide backal surface; The arc-shaped protrusion adopts a smooth arc transition mechanism and is coated with a heat-resistant and wear-resistant ceramic buffer pad. The surface of the buffer pad is provided with a guide groove for discharging fly ash from the contact surface during collision.

[0009] As a preferred embodiment of the present invention, the driving assembly includes a geared motor, a flexible transmission shaft, and a transmission mechanism arranged on the outside of the flue; all movable mesh cylinders in the same pipe bank are synchronously driven through the transmission mechanism. The transmission mechanism includes a transmission component mounted on the end of the movable mesh cylinder and a drive sprocket located below the transmission component; The geared motor is connected to the drive sprocket via a flexible drive shaft; The transmission assembly includes a sliding bearing, the inner ring of which is fixed to the outer wall of the heat exchange tube bundle, and the outer ring of which is fitted onto a driven sprocket that is sealed to the end of the movable mesh cylinder. The driven sprockets of all movable mesh cylinders in the same pipe bank are driven by chains, and the driven sprocket and the driving sprocket at the bottom are driven by chains; The sliding bearing is reserved for radial compensation; one end of the movable mesh cylinder is axially limited, and the other end is provided with an axial sliding compensation groove to release thermal expansion stress. The drive assembly is equipped with a flexible torque buffer coupling to absorb torque fluctuations caused by collisions.

[0010] As a preferred embodiment of the present invention, the support positioning ring includes a finned base, which is fitted and fixed to the outer wall of the heat exchange tube bundle. The outer end of the base is movably inserted with a base column via an elastic element, and the outer ends of the base columns are connected to a base ring, which is fixedly assembled on the inner wall of the movable mesh cylinder. A radial clearance is reserved between the support positioning ring and the inner wall of the movable mesh cylinder through an elastic element.

[0011] As a preferred technical solution of the present invention, the ash removal and collection assembly includes a pulse steam blowing unit and a bottom ash collection structure; The pulse steam soot blowing unit includes soot blowing branch pipes arranged above the gaps of each row of heat exchange tube bundles. The soot blowing branch pipes have directional soot blowing holes corresponding to the top gaps of each section of movable mesh cylinder. The soot blowing branch pipes are connected to the boiler's original superheated steam soot blowing system. The bottom ash collection structure includes a strip-shaped ash collection hopper located below the movable mesh cylinder. An electric ash discharge valve is installed at the end of the ash collection hopper and connected to the boiler's original ash conveying system.

[0012] As a preferred embodiment of the present invention, the inner wall of the movable net cylinder is provided with a plurality of short arc-shaped turbulence winglets arranged circumferentially, which rotate together with the movable net cylinder.

[0013] Compared with the prior art, the beneficial effects of the present invention are: (1) An auxiliary device for an energy-saving boiler anti-eccentric flow economizer, when the arc-shaped outward protrusions of adjacent movable screen cylinders periodically and instantaneously touch and squeeze, the movable screen cylinder can freely undergo slight radial deformation and elastic rebound, stably generating high-frequency micro-vibration effect, giving full play to the mechanical ash-shaking effect, efficiently shaking off the stubborn fly ash embedded and accumulated on the surface of the movable screen cylinder and in the mesh, ensuring the continuous and stable operation of the composite ash-removing system.

[0014] (2) An auxiliary device for an energy-saving boiler anti-deviation economizer, wherein the fin structure can disturb the annular flue gas laminar flow bottom layer between the heat exchange tube bundle and the movable mesh cylinder, enhance the flue gas turbulence disturbance effect, break the static heat exchange blind zone, further improve the convective heat transfer coefficient, and significantly improve the overall waste heat recovery efficiency without increasing energy consumption.

[0015] (3) An auxiliary device for an energy-saving boiler anti-eccentric flow economizer, wherein the opening of the guide chute forms a natural gas flow channel, the soot blowing airflow washes and carries residual fine ash particles along the guide chute, and combined with the mechanical action of collision and compression automatic ash discharge, a dual ash cleaning mechanism is formed to remove the ash accumulation in the arc-shaped convex part and surrounding area, ensuring that the contact surface of the arc-shaped convex part is always kept clean, and improving the reliability and thoroughness of the overall ash cleaning system.

[0016] (4) An auxiliary device for an energy-saving boiler anti-eccentricity economizer, which removes most of the loose and semi-adhered fly ash in advance through normal mechanical vibration, greatly reducing the workload of pulse soot blowing; the mechanical vibration can effectively remove the hard ash embedded in the mesh and the ash layer adhering to the surface, and can remove stubborn ash that cannot be removed by steam purging, thus avoiding the blockage and failure of the movable mesh cylinder from the root and greatly improving the long-term permeability of the movable mesh cylinder.

[0017] (5) An auxiliary device for an energy-saving boiler anti-eccentricity economizer, wherein the arc-shaped protrusion can generate vibration disturbance to all areas of the movable screen cylinder in the circumferential and all-area manner, which can achieve uniform ash removal of the movable screen cylinder as a whole, keep the mesh holes of the movable screen cylinder unobstructed for a long time, effectively avoid the problem of increased flue gas flow resistance and flow field distortion between tube bundles caused by local ash accumulation and blockage, and, together with the front-end flue gas flow equalization device, always maintain the uniform flue gas flow state, and ensure long-term stable heat exchange efficiency.

[0018] (6) An auxiliary device for an economizer to prevent flow deviation in an energy-saving boiler, wherein the arc-shaped turbulence vanes periodically break the static laminar boundary layer on the tube wall surface, enhancing the turbulent flow disturbance effect of flue gas and improving the convective heat transfer coefficient. The rotational motion makes the flue gas velocity distribution inside the gap more uniform, which not only does not weaken the heat transfer capacity of the tube bundle, but also slightly enhances the overall heat transfer effect; at the same time, relying on the dynamic anti-clogging characteristics, it eliminates the problem of ash accumulation and thermal resistance superposition, ensuring that the heat transfer efficiency of the economizer is stable and does not decrease in the long term.

[0019] (7) An auxiliary device for an economizer to prevent eccentricity in an energy-saving boiler, wherein the movable screen can preferentially intercept large particles of fly ash, significantly reducing the probability of perforation and leakage of the heat exchange tube bundle, ensuring the long-term safe operation of the economizer. In addition, the movable screen can buffer and divert the concentrated particle impact caused by eccentricity, weaken the local concentrated particle impact effect, and reduce the risk of heat exchange tube bundle being simultaneously damaged by wear and corrosion under eccentricity conditions, thus extending the overall service life of the tube bundle. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is a schematic diagram of the dust removal and collection component of the present invention; Figure 3 This is a schematic diagram of the flue gas equalization device of the present invention; Figure 4 This is a schematic diagram showing the position of the movable mesh cylinder of the present invention; Figure 5 This is a schematic diagram of the movable mesh tube of the present invention; Figure 6 For the present invention Figure 5 Enlarged view of point A; Figure 7 This is a schematic diagram showing the arrangement of adjacent movable mesh cylinders according to the present invention; Figure 8 This is a schematic diagram of the sliding bearing of the present invention; Figure 9 This is a schematic diagram of the driving component of the present invention; Figure 10 This is a schematic diagram showing the position of the support positioning ring in this invention; Figure 11 This is a schematic diagram of the support positioning ring of the present invention.

[0021] In the picture: 1. Economizer body; 101. Heat exchanger tube bundle; 2. Flue gas flow equalization device; 201. Flue gas pipeline; 202. Baffle plate; 203. Grating plate; 3. Protective self-cleaning device; 301. Movable mesh cylinder; 302. Arc-shaped outward protrusion; 303. Buffer pad; 304. Guide chute; 305. Turbulence wing; 4. Drive assembly; 401. Flexible drive shaft; 402. Drive sprocket; 403. Sliding bearing; 404. Driven sprocket; 5. Support positioning ring; 501. Base; 502. Base column; 503. Base ring; 6. Ash cleaning and collection assembly; 601. Pulse steam soot blowing unit; 6011. Soot blowing branch pipe; 6012. Soot blowing hole; 602. Bottom ash collection structure; 6021. Ash hopper; 6022. Electric ash discharge valve. Detailed Implementation

[0022] 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.

[0023] Example: Please refer to Figures 1-11 An auxiliary device for preventing flow deviation in an energy-saving boiler economizer includes an economizer body 1, a flue gas flow equalization device 2 arranged in series along the flue gas flow direction on the flue gas inlet side of the economizer body 1, and a protective self-cleaning device 3 correspondingly installed at the heat exchange tube bundle 101 of the economizer body 1. The protective self-cleaning device 3 includes a movable mesh cylinder 301 coaxially sleeved on the outside of each heat exchange tube bundle 101, a drive assembly 4, a finned support positioning ring 5, and a cleaning and dust collection assembly 6. The movable net cylinder 301 adopts a partially convex non-circular cross-section structure with elastic deformation capability, and the outer wall of the movable net cylinder 301 is provided with several arc-shaped convex parts 302 in the circumferential direction. A flow gap is left between the non-protruding areas of adjacent movable mesh cylinders 301; an annular gap is left between the movable mesh cylinder 301 and the outer wall of the heat exchange tube bundle 101, and it is coaxially aligned by a number of support positioning rings 5 ​​arranged at intervals along the axial direction. The drive assembly 4 is used to drive each movable screen cylinder 301 of the same tube bank to rotate synchronously at low speed around the heat exchange tube bundle 101, so that the arc-shaped protrusions 302 of adjacent movable screen cylinders 301 periodically and momentarily touch each other, causing the movable screen cylinders 301 to produce radial elastic deformation and rebound, so as to shake off the fly ash adhering to the surface and mesh of the movable screen cylinders 301 by mechanical vibration. The dust collection and cleaning component 6 is linked to the rotation of the movable screen cylinder 301 for blowing and collecting dust accumulated on the surface of the movable screen cylinder 301.

[0024] The flue gas flow equalization device 2 includes a flue gas pipeline 201. The flue gas pipeline 201 is configured with a flow guiding unit and a flow rectifying unit from upstream to downstream of the flue gas to correct the flue gas flow deviation step by step in order to output a uniform flow field. The flow guiding unit is composed of streamlined flow guide plates 202 arranged in parallel along the width direction of flue gas duct 201. The flow-facing surface of the flow guide plate 202 adopts a streamlined curved surface structure with a rounded transition. The inclination angle of the flow-facing surface of the flow guide plate 202 gradually changes from the inlet end to the outlet end along the flue gas flow direction. The rectifier unit adopts a honeycomb structure, which is formed by orthogonally splicing horizontal and vertical grid plates 203 to form a regular hexagonal honeycomb rectifier cavity; the front edge of the grid plate 203 is rounded and blunted.

[0025] The movable mesh cylinder 301 includes a wedge wire welded mesh cylinder, wherein the mesh of the wedge wire welded mesh cylinder adopts a trapezoidal cross-section structure with a narrow frontal face and a wide backal face; The arc-shaped protrusion 302 adopts a smooth arc transition mechanism, and the surface is coated with a heat-resistant and wear-resistant ceramic buffer pad 303. The surface of the buffer pad 303 is provided with a guide groove 304 for discharging fly ash from the contact surface during collision.

[0026] The drive assembly 4 includes a geared motor, a flexible drive shaft 401, and a transmission mechanism arranged on the outside of the flue; all movable mesh cylinders 301 in the same pipe bank are synchronously driven through the transmission mechanism. The transmission mechanism includes a transmission assembly mounted on the end of the movable mesh cylinder 301 and a drive sprocket 402 located below the transmission assembly; The geared motor is connected to the drive sprocket 402 via a flexible drive shaft 401; The transmission assembly includes a sliding bearing 403, the inner ring of which is fixed to the outer wall of the heat exchange tube bundle 101, and the outer ring of which is fitted with a driven sprocket 404 that is sealed to the end of the movable mesh cylinder 301. All driven sprockets 404 of the movable mesh cylinders 301 in the same pipe bank are driven by chains, and the lowest driven sprocket 404 and the driving sprocket 402 are driven by chains. The sliding bearing 403 is reserved for radial compensation; the movable mesh cylinder 301 is axially limited at one end and has an axial sliding compensation groove at the other end to release thermal expansion stress. The drive assembly 4 is equipped with a flexible torque buffer coupling to absorb torque fluctuations caused by collisions.

[0027] The support positioning ring 5 includes a finned base 501, which is attached to and fixed to the outer wall of the heat exchange tube bundle 101. A base column 502 is movably inserted into the outer end of the base 501 via an elastic element. The outer ends of the base column 502 are connected to a base ring 503, which is fixedly mounted on the inner wall of the movable mesh cylinder 301. A radial clearance is reserved between the support positioning ring 5 and the inner wall of the movable mesh cylinder 301 through an elastic element to allow the movable mesh cylinder 301 to undergo a small radial elastic deformation.

[0028] The dust removal and collection assembly 6 includes a pulse steam blowing unit 601 and a bottom dust collection structure 602; The pulse steam soot blowing unit 601 includes a soot blowing branch pipe 6011 arranged above the gap of each row of heat exchange tube bundles 101. The soot blowing branch pipe 6011 has a directional soot blowing hole 6012 corresponding to the top gap of each section of movable mesh cylinder 301. The soot blowing branch pipe 6011 is connected to the original superheated steam soot blowing system of the boiler. The bottom ash collection structure 602 includes a strip-shaped ash collection hopper 6021 located below the movable mesh cylinder 301. An electric ash discharge valve 6022 is installed at the end of the ash collection hopper 6021 and connected to the boiler's original ash conveying system.

[0029] Several short arc-shaped turbulence wing 305 are arranged circumferentially on the inner wall of the movable screen cylinder 301, and rotate together with the movable screen cylinder 301. The turbulence wing 305 stirs the flue gas in the annular gap, periodically destroys the inner boundary layer of the movable screen cylinder 301, prevents fine ash from being deposited on the back of the movable screen cylinder 301, and at the same time uniformizes the flue gas velocity in the gap.

[0030] The working principle of this invention is as follows: The radial clearance reserved in the support positioning ring 5 can accurately radially straighten the movable screen cylinder 301 in the rotating state, effectively controlling the radial runout of the movable screen cylinder 301 during operation, avoiding irregular scraping and jamming problems between adjacent movable screen cylinders 301. At the same time, the small clearance provides sufficient margin for the elastic deformation of the movable screen cylinder 301. In addition, the vibration stress of the movable screen cylinder 301 will not be directly transmitted to the heat exchange tube bundle 101 of the economizer body 1. When the arc-shaped protrusions 302 of adjacent movable screen cylinders 301 periodically and momentarily touch and squeeze, the movable screen cylinder 301 can freely undergo a small radial deformation and elastic rebound, stably generating a high-frequency micro-vibration effect, giving full play to the mechanical ash removal function, efficiently shaking off the stubborn fly ash embedded and accumulated on the surface and inside the mesh of the movable screen cylinder 301, ensuring the continuous and stable operation of the composite ash removal system.

[0031] The base 501 supporting the positioning ring 5 is designed with fins. The base 501 is closely attached to the outer wall of the heat exchange tube bundle 101, which can quickly absorb the heat energy conducted by the heat exchange tube bundle 101. The extended fin structure expands the contact heat exchange area with the interstitial flue gas, effectively expanding the effective heat exchange interface of the heat exchange tube bundle 101. At the same time, the fin structure can disturb the annular laminar flow bottom layer of flue gas between the heat exchange tube bundle 101 and the movable mesh cylinder 301, enhance the flue gas turbulence disturbance effect, break the static heat exchange blind zone, and further improve the convective heat transfer coefficient. Without increasing energy consumption, it significantly improves the overall waste heat recovery efficiency.

[0032] By providing a flow guide groove 304 on the surface of the buffer pad 303, the fly ash that is squeezed during the collision can slide outward and fall off quickly along the channel of the flow guide groove 304. The flow guide groove 304 forms a natural gas flow channel. The soot blowing airflow washes and carries away residual fine ash particles along the flow guide groove 304. Combined with the mechanical action of automatic ash discharge by collision and compression, a dual ash removal mechanism is formed to remove the ash accumulated in the arc-shaped protrusion 302 and the surrounding area, ensuring that the contact surface of the arc-shaped protrusion 302 is always kept clean, and improving the reliability and thoroughness of the overall ash removal system.

[0033] Relying on the rotational characteristics of the movable screen cylinder 301, the arc-shaped protrusions 302 of adjacent movable screen cylinders 301 periodically and briefly contact and squeeze, causing the movable screen cylinder 301 to produce slight deformation and instantaneous rebound vibration, forming a regular micro-shaking effect. Through normalized mechanical shaking, most of the loose and semi-adhered fly ash is removed in advance, significantly reducing the workload of pulse soot blowing. This mechanical vibration can effectively remove the hard ash embedded in the mesh and the ash layer adhering to the surface, and can remove stubborn ash that cannot be removed by steam blowing, thus preventing the movable screen cylinder 301 from clogging and failure at the source, and greatly improving the long-term permeability of the movable screen cylinder 301.

[0034] The movable screen cylinder 301 rotates at low speed, and the arc-shaped outward protrusion 302 can generate vibration disturbance to all areas of the movable screen cylinder 301 in a circumferential and all-area manner, eliminating the fixed dead corners for ash accumulation. Combined with the pulse blowing cleaning of the pulse steam blowing unit 601, it can achieve uniform ash removal of the entire movable screen cylinder 301, keeping the mesh openings of the movable screen cylinder 301 unobstructed for a long time. This effectively avoids the problems of increased flue gas flow resistance and flow field distortion between tube bundles caused by local ash accumulation and blockage. Combined with the front-end flue gas equalization device 2, it always maintains a uniform flue gas flow state, ensuring long-term stable heat exchange efficiency.

[0035] The arc-shaped turbulence-inducing vanes 305 arranged circumferentially on the inner wall of the movable mesh cylinder 301 rotate synchronously with the movable mesh cylinder 301, continuously disturbing the flue gas in the annular gap between the heat exchange tube bundle 101 and the movable mesh cylinder 301. This periodically breaks the static laminar boundary layer on the tube wall surface, enhancing the turbulent flow disturbance effect of the flue gas and improving the convective heat transfer coefficient. The rotational motion makes the flue gas velocity distribution inside the gap more uniform, which not only does not weaken the heat exchange capacity of the tube bundle, but also slightly enhances the overall heat exchange effect. At the same time, relying on the dynamic anti-clogging characteristics, it eliminates the problem of ash accumulation and thermal resistance superposition, ensuring that the economizer's heat exchange efficiency remains stable and without decay over a long period of time.

[0036] The movable screen 301 can preferentially intercept large fly ash particles, preventing hard, large particles from directly impacting and cutting the outer wall of the heat exchange tube bundle 101. This weakens the erosion and wear rate of the heat exchange tube bundle 101 from the source, significantly reducing the probability of perforation and leakage in the heat exchange tube bundle 101, and ensuring the long-term safe operation of the economizer. In addition, the movable screen 301 can buffer and divert the concentrated particle impact caused by the flow deviation, weakening the local concentrated particle impact effect and reducing the risk of the heat exchange tube bundle 101 suffering from the superposition of wear and corrosion damage under the flow deviation condition, thus extending the overall service life of the tube bundle.

[0037] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An auxiliary device for an economizer to prevent flow deviation in an energy-saving boiler, comprising an economizer body (1) and a flue gas flow equalization device (2) arranged in series along the flue gas flow direction on the flue gas inlet side of the economizer body (1), and a protective self-cleaning device (3) correspondingly installed at the heat exchange tube bundle (101) of the economizer body (1). Its features are: The protective self-cleaning device (3) includes a movable mesh cylinder (301) coaxially sleeved on the outside of each heat exchange tube bundle (101), a drive assembly (4), a finned support positioning ring (5), and a cleaning and dust collection assembly (6). The movable net cylinder (301) adopts a partially convex non-circular cross-section structure with elastic deformation capability, and the outer wall of the movable net cylinder (301) is provided with several arc-shaped convex parts (302) in the circumferential direction. A flow gap is left between the non-protruding areas of adjacent movable mesh cylinders (301); an annular gap is left between the movable mesh cylinder (301) and the outer wall of the heat exchange tube bundle (101), and it is coaxially aligned by a number of support positioning rings (5) arranged at intervals along the axial direction; The drive assembly (4) is used to drive each movable screen cylinder (301) of the same tube bank to rotate synchronously at low speed around the heat exchange tube bundle (101), so that the arc-shaped protrusions (302) of adjacent movable screen cylinders (301) periodically and momentarily touch each other, causing the movable screen cylinders (301) to produce radial elastic deformation and rebound, so as to shake off the fly ash adhering to the surface and mesh of the movable screen cylinders (301) by mechanical vibration; The dust removal and collection component (6) is linked to the rotation of the movable screen cylinder (301) for blowing and collecting dust on the surface of the movable screen cylinder (301).

2. The auxiliary device for an energy-saving boiler economizer to prevent eccentricity as described in claim 1, characterized in that: The flue gas flow equalization device (2) includes a flue gas pipeline (201), and the flue gas pipeline (201) is configured with a flow guiding unit and a flow rectifying unit from upstream to downstream of the flue gas to correct the flue gas flow deviation step by step in order to output a uniform flow field; The flow guiding unit is composed of streamlined flow guide plates (202) arranged in parallel along the width direction of the flue gas pipeline (201). The flow-facing surface of the flow guide plate (202) adopts a streamlined curved surface structure with a rounded transition. The inclination angle of the flow-facing surface of the flow guide plate (202) gradually changes from the inlet end to the outlet end along the flue gas flow direction. The rectifier unit adopts a honeycomb structure, which is formed by orthogonally splicing horizontal and vertical grid plates (203) to form a regular hexagonal honeycomb rectifier cavity; the front edge of the grid plate (203) is rounded and blunted.

3. The auxiliary device for an energy-saving boiler economizer to prevent eccentricity as described in claim 1, characterized in that: The movable mesh cylinder (301) includes a wedge wire welded mesh cylinder, wherein the mesh of the wedge wire welded mesh cylinder adopts a trapezoidal cross-section structure with a narrow frontal face and a wide backal face; The arc-shaped protrusion (302) adopts a smooth arc transition mechanism and is coated with a heat-resistant and wear-resistant ceramic buffer pad (303). The buffer pad (303) has a guide groove (304) on its surface to discharge fly ash from the contact surface during collision.

4. The auxiliary device for an energy-saving boiler economizer to prevent eccentricity as described in claim 1, characterized in that: The drive assembly (4) includes a geared motor, a flexible transmission shaft (401) and a transmission mechanism arranged on the outside of the flue; all movable mesh cylinders (301) in the same pipe bank are synchronously driven through the transmission mechanism; The transmission mechanism includes a transmission component mounted on the end of the movable mesh cylinder (301) and a drive sprocket (402) located below the transmission component. The geared motor is connected to the drive sprocket (402) via a flexible transmission shaft (401). The transmission assembly includes a sliding bearing (403), the inner ring of which is fixed to the outer wall of the heat exchange tube bundle (101), and the outer ring of which is fitted with a driven sprocket (404) that is sealed to the end of the movable mesh cylinder (301). The driven sprockets (404) of all movable mesh cylinders (301) in the same pipe bank are driven by chains, and the driven sprocket (404) and the driving sprocket (402) at the bottom are driven by chains; The sliding bearing (403) is reserved for radial compensation; the movable mesh cylinder (301) is axially limited at one end and has an axial sliding compensation groove at the other end to release thermal expansion stress; The drive assembly (4) is equipped with a flexible torque buffer coupling to absorb torque fluctuations caused by collisions.

5. An auxiliary device for an energy-saving boiler economizer to prevent eccentricity as described in claim 1, characterized in that: The support positioning ring (5) includes a finned base (501), which is attached to and fixed to the outer wall of the heat exchange tube bundle (101). The base (501) has a base column (502) movably inserted into its outer end via an elastic element. The outer ends of the base column (502) are connected to a base ring (503), which is fixedly mounted on the inner wall of the movable mesh cylinder (301). The support positioning ring (5) and the inner wall of the movable mesh cylinder (301) are provided with a radial clearance through an elastic element.

6. The auxiliary device for an energy-saving boiler economizer to prevent eccentricity as described in claim 1, characterized in that: The dust removal and dust collection assembly (6) includes a pulse steam blowing unit (601) and a bottom dust collection structure (602). The pulse steam soot blowing unit (601) includes a soot blowing branch pipe (6011) arranged above the gap of each row of heat exchange tube bundles (101). The soot blowing branch pipe (6011) has a directional soot blowing hole (6012) corresponding to the top gap of each section of movable mesh cylinder (301). The soot blowing branch pipe (6011) is connected to the original superheated steam soot blowing system of the boiler. The bottom ash collection structure (602) includes a strip-shaped ash collection hopper (6021) located below the movable mesh cylinder (301). An electric ash discharge valve (6022) is provided at the end of the ash collection hopper (6021) and connected to the original ash conveying system of the boiler.

7. An auxiliary device for an energy-saving boiler economizer to prevent eccentricity as described in claim 3, characterized in that: The inner wall of the movable net cylinder (301) is arranged with several short arc-shaped turbulence wings (305) in the circumferential direction, which rotate together with the movable net cylinder (301).

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