A high-sulfur coal-tungsten carbide alloyed steel tube and a method for manufacturing the same

Abstract

The application discloses a high-sulfur coal enamel economizer device with self-cleaning filtration and online soot blowing and a method thereof. The device comprises a box body, a heat exchange assembly, an online blowing assembly and a stepped self-cleaning filtration assembly. The box body is communicated with an inlet and outlet flue gas passage at both ends and is provided with an enamel heat exchange surface on the inner wall. The fins are integrally formed with tilted and raised fins from top to bottom. The online soot blowing assembly is symmetrically arranged on the side wall of the box body and is composed of a communicating connection box and a one-way high-pressure nozzle. The stepped self-cleaning filtration assembly is arranged at the front end of the inlet flue gas passage. The device integrates the front filtration, the turbulent heat exchange and the built-in partition soot blowing structure. The front filtration pre-intercepts dust, reduces the enamel erosion and wear, the raised fins form the turbulent flow to strengthen the heat exchange, the one-way nozzle sweeps the whole area without dead angle, and the high-sulfur flue gas corrosion, the ash deposition and blockage and the low-efficiency heat exchange defects are simultaneously solved, so that the long-term continuous and stable operation of the boiler can be ensured.

Description

Technical Field

[0001] This invention belongs to the technical field of tail heat exchange equipment for high-sulfur fuel boilers, specifically relating to a device and method for a high-sulfur coal enamel economizer with self-cleaning filter and online soot blowing. Background Technology

[0002] When industrial boilers burning high-sulfur coal are in operation, the flue gas carries a large amount of sulfur oxides and coarse and fine dust particles, which easily corrode the economizer heat exchange surface and accumulate ash, significantly reducing waste heat recovery efficiency. Current technologies generally use enamel coatings to improve the corrosion resistance of heat exchange tubes, but this still has several drawbacks: First, the flue gas is not pre-filtered, and large fly ash particles directly wash over the enamel heat exchange surface, easily causing coating wear and pipe blockage; conventional filters lack online cleaning structures, requiring shutdown for disassembly and cleaning, seriously affecting continuous boiler operation. Second, traditional economizer fins are mostly straight structures, making it easy for the flue gas to form a laminar boundary layer, resulting in low heat exchange efficiency, and ash easily accumulates in a flat layer. Third, existing soot blowing devices are mostly externally arranged, which cannot fully cover the dead corners of the tube bundle, and lack a one-way backflow prevention structure, making it easy for flue gas dust to backflow and contaminate the purging pipeline; it is impossible to completely remove ash from the enamel surface while the boiler is running, and long-term ash accumulation will accelerate the aging and corrosion of the coating; existing technologies only improve the single structure of filtration, soot blowing or heat exchange fins, without an integrated modular enamel economizer that integrates pre-stage self-cleaning filtration, turbulence-enhanced heat exchange, and built-in layered online soot blowing, making it difficult to simultaneously solve multiple pain points such as high-sulfur coal flue gas corrosion, ash accumulation and pipe blockage, and heat exchange efficiency decline. Summary of the Invention

[0003] The purpose of this invention is to provide a device and method for a high-sulfur coal enamel economizer with self-cleaning filter and online soot blowing, in order to solve the technical defects of existing enamel economizers, such as the lack of pre-stage self-cleaning filter, poor heat exchange effect of flat fins, dead corners in external soot blowing and easy backflow of flue gas dust, which leads to wear and blockage of heat exchange surface, reduction of heat exchange efficiency, and difficulty in cleaning ash accumulation online without stopping the machine.

[0004] To achieve the above objectives, this application provides the following technical solution: The first aspect of this application provides a high-sulfur coal enamel economizer device with self-cleaning filter and online soot blowing, comprising: The housing has a smoke inlet channel and a smoke outlet channel connected to both ends, and the inner wall of the housing is lined with an enamel heat exchange surface. The heat exchange assembly is arranged inside the housing. The heat exchange assembly includes an S-shaped continuous bend and heat exchange fins. The two ends of the S-shaped continuous bend are respectively connected to the water inlet pipe and the water collection pipe. The heat exchange fins are fixed to the outer wall of the S-shaped continuous bend at equal intervals. The two sides of the heat exchange fins are integrally stamped and formed, with the fins tilted from top to bottom along the flue gas flow direction. An online soot blowing assembly is symmetrically fixed to the side wall of the housing. The online soot blowing assembly includes a connecting box and a one-way high-pressure nozzle. The connecting boxes are interconnected by pipelines. The top of the upper connecting box is connected to a cleaning delivery pipe. The inner side of the connecting box penetrates the side wall of the housing and extends into the inner cavity of the housing. The one-way high-pressure nozzle is threadedly assembled to the end of the connecting box located in the inner cavity. The spray end of the one-way high-pressure nozzle faces the S-shaped continuous bend and heat exchange fins. A tiered self-cleaning filter assembly is installed at the front end of the smoke inlet channel to pre-intercept dust particles inside the smoke.

[0005] In one optional embodiment, the cascade self-cleaning filter assembly includes: Rectangular cylindrical body, rectangular ear plate, and drain outlet blocking plate; The rectangular ear plate is integrally welded to both ends of the rectangular cylinder, and several through holes are evenly provided on the rectangular ear plate; The top flange face of the smoke inlet channel is provided with a through hole one that matches through hole two. The rectangular cylinder is detachably and sealed to the front end of the smoke inlet channel by bolts passing through through hole two and through hole one. The drain plug plate is detachably mounted on the side wall of the rectangular cylinder.

[0006] In one optional embodiment, the interior of the rectangular cylinder includes: Three-layer rectangular frame and filter screen; The three-layer rectangular frame is fixed in layers inside the rectangular cylinder along the downward direction of the flue gas, and each layer of the rectangular frame is equipped with a filter screen. The three-layer filter screen has a progressively smaller mesh size from top to bottom along the flue gas flow direction, which is used to achieve tiered and layered interception of flue gas dust.

[0007] In one alternative embodiment, the filter cleaning assembly includes: Electric actuator, connecting plate and brush; The output end of the electric push rod is fixedly connected to the connecting plate, and the brush is vertically assembled at the bottom of the connecting plate. The electric push rod is provided in three sets, and the three sets of electric push rods are arranged along the outside of the rectangular cylinder. The connecting plate connected to each electric push rod is suspended above the first layer of rectangular frame. The bristles of the brush adhere to the surface of the corresponding filter layer, allowing for repeated sweeping of accumulated dust along the filter.

[0008] In one optional embodiment, a dust accumulation and settling area is formed at the bottom of the rectangular cylinder; The electric push rod drives the connecting plate and the brush to move horizontally and reciprocally in sync. The brush scrapes the dust on the surface of the filter screen, and the dust settles down along the slope of the filter screen into the dust settling area, so as to realize the filter screen cleaning online without stopping the machine.

[0009] In one optional embodiment, the raised fins are arranged inclined from top to bottom along the flue gas flow direction and surround the heat exchange fins to form a turbulence gap; As flue gas flows, the raised plates can continuously tear the laminar boundary layer of the flue gas to form turbulence, and the inclined slope of the raised plates can prevent dust from spreading and accumulating.

[0010] In one optional embodiment, four connecting boxes are fixed to the left and right side walls of the box by bolts, and the four connecting boxes on the same side are arranged in layers at equal intervals along the height direction of the box. Each connecting box has multiple sets of unidirectional high-pressure nozzles threaded onto its end that extends into the inner cavity of the box.

[0011] In one optional embodiment, the connecting boxes arranged in layers on the same side are sequentially connected by three horizontally arranged connecting pipes. The top of the connecting boxes on both sides of the box body is connected to a cleaning delivery pipe. The one-way high-pressure nozzle is equipped with a one-way valve structure inside. The one-way valve structure is used to spray high-pressure cleaning medium outward to prevent flue gas and dust inside the box from flowing back into the connecting box and the cleaning delivery pipe.

[0012] In an optional embodiment, it further includes: Smoke inlet pipe and smoke outlet pipe; The smoke inlet pipe is located at the top of the housing, and the housing forms the smoke inlet channel through the smoke inlet pipe; The smoke outlet pipe is located at the bottom of the box, and the box forms the smoke outlet channel through the smoke outlet pipe.

[0013] A second aspect of this application provides a method for flue gas heat exchange and self-cleaning operation based on a high-sulfur coal enamel economizer device with self-cleaning filter and online soot blowing as described above, characterized in that it includes: High-temperature and high-sulfur flue gas is introduced into the stepped self-cleaning filter component through the flue gas inlet pipe. The flue gas passes through multiple layers of filter screens with progressively smaller mesh sizes from top to bottom, completing the graded interception of dust particles of different sizes. The brush driven by the electric push rod reciprocates to clean the dust on the surface of the filter screen. The dust settles to the dust accumulation area at the bottom of the rectangular cylinder. The discharge port blockage plate is disassembled periodically to collect and discharge the accumulated dust. After filtration, the flue gas enters the interior of the box through the flue gas inlet channel, and is laterally washed by the S-shaped continuous bend and heat exchange fins. The raised fins tear the laminar boundary layer of the flue gas to form turbulence and enhance heat exchange. The boiler feedwater is introduced into the S-shaped continuous bend through the water inlet pipe. After the medium inside the pipe absorbs the heat of the flue gas, it is collected in the water collection pipe and transported outward. During the heat exchange process, the online soot blowing component is activated periodically. The high-pressure cleaning medium is sent into the layered connection box through the cleaning delivery pipe and is sprayed directionally by the one-way high-pressure nozzle onto the S-shaped continuous bend and the enamel surface of the heat exchange fins to peel off the attached ash. The one-way valve structure prevents the flue gas and dust in the box from flowing back into the soot blowing pipeline. After heat exchange and dust removal, the low-temperature flue gas is discharged to the subsequent flue gas treatment system through the flue gas outlet pipe at the bottom of the chamber.

[0014] Compared with the prior art, the present invention has the following beneficial effects: 1. By incorporating an enamel-lined inner wall, turbulent heat exchange components, online soot blowing components, and a stepped self-cleaning filter structure within the boiler housing, the defects of traditional economizers, such as lack of pre-dust removal, low heat exchange efficiency, and dead corners in soot blowing, are overcome. The filter pre-intercepts large dust particles to reduce erosion and wear on the enamel surface, the turbulent fins improve heat exchange efficiency, and the built-in unidirectional nozzles eliminate blind spots in the blowing process. This simultaneously solves multiple problems such as corrosion from high-sulfur flue gas, ash accumulation and blockage, and low heat exchange efficiency, ensuring long-term continuous and stable operation of the boiler.

[0015] 2. The cascade self-cleaning filter assembly is equipped with rectangular ear plates and a detachable drain port blockage plate. The cylinder seal is quickly disassembled and assembled using flange bolts, overcoming the defects of cumbersome maintenance and disassembly of the integrated cylinder and the complicated ash removal operation. The accumulated ash can be cleaned without disassembling the entire cylinder. The filter module can be disassembled and maintained independently, greatly reducing the equipment maintenance downtime.

[0016] 3. Three layers of progressively smaller pore size filter screens are arranged in the rectangular cylinder to achieve graded interception of flue gas dust. This overcomes the defects of single-layer filter screens, such as concentrated load and easy rapid clogging. The layered interception and dispersion of coarse and fine dust reduces the pressure on the filter media, significantly reducing the probability of large fly ash particles entering the housing and abrading the enamel heat exchange layer, and extending the continuous service life of the filter screens.

[0017] 4. The system is equipped with three sets of electric push rods, connecting plates and brushes to form a layered cleaning mechanism. The push rods drive the brushes to scrape against each layer of filter screens back and forth, overcoming the drawbacks of cumbersome manual disassembly and cleaning of filter screens and the need to stop the machine. Each layer of filter screens is automatically cleaned independently without stopping the machine to disassemble the filter components, thus continuously maintaining a stable flow of flue gas through the filter screens.

[0018] 5. A dust settling area is reserved at the bottom of the cylinder. The dust that is swept off naturally collects along the slope of the filter screen, which overcomes the defect that dust is scattered in various parts of the cylinder and is difficult to clean. The dust is concentrated in the bottom settling area, and can be discharged in a concentrated manner with the side wall blocking plate. The filter screen cleaning, dust settling and concentrated dust discharge form a closed loop to continuously ensure smooth flue gas flow.

[0019] 6. The heat exchange fins are integrally formed with inclined and raised fins on both sides to form a turbulence gap. The airflow forms turbulence to enhance heat exchange, which overcomes the defects of flat fins that are prone to laminar flow, poor heat exchange efficiency, and easy dust accumulation. It increases the heat exchange contact area of ​​flue gas, reduces the amount of ash adhering to the fins, and reduces the load of subsequent online soot blowing operations.

[0020] 7. Multiple sets of connection boxes with unidirectional high-pressure nozzles are arranged at equal intervals on both sides of the box. The nozzles fully cover the entire heat exchange tube bundle area, overcoming the defects of limited blowing range of external soot blowing devices and dead corners of ash accumulation in the upper and lower areas. It can fully cover the bends and fins, effectively remove the ash and dirt attached to the enamel surface, and protect the integrity of the anti-corrosion coating.

[0021] 8. The same-side connection boxes are connected through horizontal pipelines, and the top layer is uniformly connected to the cleaning delivery pipe. The nozzle has a built-in one-way valve structure, which overcomes the defects of uneven media distribution and easy backflow of flue gas and dust to block the pipeline in the soot blowing pipeline. It stabilizes the blowing media delivery pressure, prevents high-temperature dust backflow from corroding the pipeline, and extends the service life of the entire soot blowing system.

[0022] 9. The top and bottom of the enclosure are respectively equipped with detachable and sealed smoke inlet pipes and smoke outlet pipes to form a complete smoke passage. The pipe fittings are reserved with through holes for flange assembly, which overcomes the defects of difficult disassembly and assembly of integrated smoke passage and poor sealing on site. The modular and split structure simplifies hoisting and assembly, and reduces the risk of air leakage and dust leakage during flue connection. Attached Figure Description

[0023] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This invention provides an overall schematic diagram of a high-sulfur coal enamel economizer device with self-cleaning filter and online soot blowing. Figure 2 A side view of a high-sulfur coal enamel economizer device with self-cleaning filter and online soot blowing provided by the present invention; Figure 3 A schematic diagram of the interior of the housing of a high-sulfur coal enamel economizer device with self-cleaning filter and online soot blowing provided by the present invention; Figure 4 A schematic diagram of the filter assembly in a high-sulfur coal enamel economizer device with self-cleaning filter and online soot blowing provided by the present invention; In the diagram: 1. Housing; 2. Exhaust pipe; 3. Inlet pipe; 4. S-shaped continuous bend; 5. Connecting pipe one; 6. Water inlet pipe; 7. Connecting pipe two; 8. Water outlet pipe; 9. Cascade self-cleaning filter assembly; 10. Connecting box; 11. Connecting pipe three; 12. Through hole one; 13. Cleaning delivery pipe; 14. One-way high-pressure nozzle; 15. Heat exchange fins; 16. Raised plate; 17. Rectangular cylinder; 18. Rectangular ear plate; 19. Through hole two; 20. Rectangular frame; 21. Filter screen; 22. Electric push rod; 23. Connecting plate; 24. High-temperature resistant brush; 25. Drainage port blockage plate. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0026] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0027] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0028] To address the technical deficiencies mentioned in the background section, this embodiment provides a device and method for a high-sulfur coal enamel economizer with self-cleaning filter and online soot blowing.

[0029] The present invention will now be described in further detail with reference to the accompanying drawings: like Figures 1-4As shown, in a first aspect of the present invention, a high-sulfur coal enamel economizer device with self-cleaning filter and online soot blowing is provided, comprising: a housing 1, with an inlet flue gas channel and an outlet flue gas channel respectively connected at both ends, and an enamel heat exchange surface laid on the inner wall of the housing 1; a heat exchange assembly arranged inside the housing 1, the heat exchange assembly including an S-shaped continuous bend 4 and heat exchange fins 15, the two ends of the S-shaped continuous bend 4 being connected to an inlet water pipe and a collection water pipe respectively, the heat exchange fins 15 being equidistantly fixed to the outer wall of the S-shaped continuous bend 4, and the heat exchange fins 15 having two integrally stamped, upwardly inclined, curved plates 16 along the flue gas flow direction on both sides; online soot blowing; The soot blowing assembly is symmetrically fixed to the side wall of the housing 1. The online soot blowing assembly includes a connecting box 10 and a one-way high-pressure nozzle 14. Each connecting box 10 is interconnected by a pipeline. The top of the upper connecting box 10 is connected to a cleaning delivery pipe 13. The inner side of the connecting box 10 penetrates the side wall of the housing 1 and extends into the inner cavity of the housing 1. The one-way high-pressure nozzle 14 is threadedly assembled to the end of the connecting box 10 located in the inner cavity. The spray end of the one-way high-pressure nozzle 14 faces the S-shaped continuous bend pipe 4 and the heat exchange fins 15. The stepped self-cleaning filter assembly 9 is set at the front end of the flue gas inlet channel to pre-intercept dust particles inside the flue gas.

[0030] The entire housing 1 is constructed from high-temperature resistant, low-carbon steel plates, welded together without segmented weld seams, effectively reducing the risk of leakage under high-temperature and acidic flue gas conditions. The inner wall surface of housing 1 is uniformly sprayed with a high-temperature corrosion-resistant special enamel coating, forming an enamel heat exchange surface. When high-sulfur, high-temperature flue gas comes into direct contact with the inner wall of housing 1, the enamel insulation layer can completely block the low-temperature dew point corrosion of the steel plate caused by sulfur dioxide and sulfuric acid trioxide contained in the flue gas, fundamentally solving the industry defects of traditional steel economizer shell corrosion perforation and short overall equipment service life.

[0031] The housing 1 is naturally divided into three independent sealed chambers along its vertical height: the top air inlet section, the middle heat exchange section, and the bottom air outlet section, from top to bottom. The top end face of the housing 1 is connected to the smoke inlet channel, and the bottom end face of the housing 1 is connected to the smoke outlet channel. High-temperature, high-sulfur, dusty flue gas flows into the housing from the top air inlet area of ​​the housing 1. In the middle heat exchange chamber, waste heat recovery and online high-pressure purging and ash removal processes are completed. The cooled clean flue gas is finally discharged outward from the bottom air outlet area of ​​the housing 1, forming a stable and continuous unidirectional flue gas flow path from top to bottom. The flue gas flow path is regular and there are no local eddy dust accumulation dead corners.

[0032] In this embodiment, the housing 1 is equipped with a smoke inlet pipe 3 and a smoke outlet pipe 2, which serve as the solid load-bearing structures for the smoke inlet channel and the smoke outlet channel, respectively. The smoke inlet pipe 3 is fixed to the top end face of the housing 1, and the hollow pipe inside the smoke inlet pipe 3 directly forms the front-end smoke inlet channel. The smoke outlet pipe 2 is assembled to the bottom end face of the housing 1, and the hollow pipe inside the smoke outlet pipe 2 forms the rear-end smoke outlet channel.

[0033] Both the inlet pipe 3 and the outlet pipe 2 have integrally stamped flanges at their ends. Multiple sets of through holes 12 are equidistantly opened on the circumference of the flanges. The through holes 12 are used to achieve sealing connection. The flange assembly structure can realize the disassembly and hoisting of the housing 1 and the cascade self-cleaning filter assembly 9. The equipment can be disassembled and operated separately during factory delivery, transportation, on-site installation, and subsequent maintenance, completely avoiding the disadvantages of the difficulty in transporting the integrated large flue shell and the need for overall disassembly and repair for partial damage.

[0034] Heat exchange components are arranged inside the heat exchange chamber in the middle of the box 1. The heat exchange components are housed in the heat exchange section of the middle of the box 1. The heat exchange components include multiple S-shaped continuous bends 4 and multiple heat exchange fins 15. The multiple S-shaped continuous bends 4 are arranged in a uniform matrix along the transverse and longitudinal directions of the box 1. Each S-shaped continuous bend 4 adopts an integral continuous bending and forming process. There are no segmented welding joints in the pipe body, which greatly reduces the risk of pipeline leakage under high temperature dust erosion and acidic media corrosion conditions.

[0035] All S-shaped continuous bends 4 have their inlet end welded to connecting pipe 1 5, and inlet pipe 6 is welded vertically to the outer wall of connecting pipe 1 5; all S-shaped continuous bends 4 have their outlet end welded to connecting pipe 2 7, and outlet pipe 8 is welded vertically to the outer wall of connecting pipe 2 7.

[0036] Low-temperature feedwater from the boiler is sent into connecting pipe 1 5 via inlet pipe 6 and evenly distributed into each S-shaped continuous bend pipe 4. The circulating feedwater flows continuously within the meandering S-shaped continuous bend pipe, fully absorbing the waste heat carried by the high-temperature flue gas outside the pipe. The medium that has absorbed heat and increased in temperature is uniformly collected in connecting pipe 2 7 and transported to the boiler drum, heating system, or other waste heat utilization equipment via outlet pipe 8, thus completing the flue gas waste heat recovery process.

[0037] Each S-shaped continuous bend 4 has heat exchange fins 15 welded and fixed at equal intervals on its outer wall surface. The heat exchange fins 15 are arranged perpendicular to the tube axis of the S-shaped continuous bend 4. A fixed flue gas flow gap is reserved between two adjacent heat exchange fins 15 to ensure that high-temperature flue gas can pass through all fin surfaces evenly, maximizing the contact area between flue gas and heat exchange components.

[0038] The single heat exchange fin 15 is made of high-temperature resistant stainless steel sheet by stamping. The left and right sides of the heat exchange fin 15 are integrally formed with raised pieces 16. The raised pieces 16 and the heat exchange fin 15 are not welded together, resulting in higher overall structural strength. Under long-term high-temperature alternating vibration conditions of the boiler, cracking and falling off will not occur. The raised pieces 16 are strictly inclined and bent from top to bottom along the overall flue gas flow direction. The raised pieces 16 and the main plate of the heat exchange fin 15 form an open turbulence gap. All raised pieces have a uniform tilt angle and uniform stamping height to ensure that the turbulence enhancement heat exchange effect is uniform and stable when the flue gas flows through each set of fins.

[0039] Online soot blowing components are symmetrically installed on the outer walls of the left and right sides of the housing 1. The double-sided soot blowing structure is arranged in a completely mirrored manner, which can cover the entire heat exchange area inside the housing in all directions without any blind spots. The basic unit of the online soot blowing component includes a connecting box 10 and a unidirectional high-pressure nozzle 14. Four independent, enclosed, pressure-resistant connecting boxes 10 are fixed to one side wall of the housing 1 by high-strength fastening bolts. The four connecting boxes 10 on the same side are arranged at equal intervals along the vertical height of the housing, corresponding to the upper, upper middle, lower middle, and four heat exchange areas inside the housing, respectively. The layered and independent arrangement structure can allocate high-pressure blowing medium separately according to the degree of ash accumulation in each area, avoiding the problem of insufficient pressure of the bottom nozzle and incomplete ash cleaning caused by centralized air supply in a single layer.

[0040] A single connecting box 10 has an integrally extended tubular section facing the inside of the box body. The tubular section penetrates the side wall of the box body and extends into the heat exchange cavity of the box body. The end of the tube body of the connecting box 10 that extends into the cavity is equipped with multiple sets of unidirectional high-pressure nozzles 14 using a threaded structure. The threaded assembly method makes it easy to disassemble and replace the nozzles individually after they are worn or blocked, without having to disassemble the connecting box 10 as a whole.

[0041] All unidirectional high-pressure nozzles 14 have their spray tips uniformly facing the surface of the S-shaped continuous bend 4 and heat exchange fins 15 inside the box, and the spray range completely covers all heat exchange components on the same side; the two adjacent connection boxes 10 on the same side are sealed and welded together by horizontally laid connection pipe three 11. Connection pipe three 11 is made of seamless pressure-resistant steel pipe to ensure that the pressure of the purging medium inside all connection boxes on the same side is uniform; the top of the top connection box 10 on the left and right sides of the box is independently sealed and connected to the cleaning delivery pipe 13. External high-pressure steam, compressed air and other cleaning media are sent into the top connection box through the cleaning delivery pipe 13, and then evenly distributed downwards to all connection boxes 10 on the lower level through connection pipe three 11. The entire soot blowing pipeline system delivers media smoothly and distributes it evenly.

[0042] Each set of one-way high-pressure nozzles 14 has an integrated one-way valve structure built into its inner cavity. The one-way valve only allows the high-pressure cleaning medium to be sprayed unidirectionally from the connecting box 10 into the box 1, completely blocking the backflow of high-temperature flue gas and dust particles into the connecting box 10, connecting pipe 3 11, and cleaning delivery pipe 13. This prevents dust from clogging the pipeline and acidic flue gas from corroding the soot blowing pipeline, significantly reducing the frequency of disassembly, cleaning, and maintenance of the soot blowing system and extending the service life of the entire online soot cleaning equipment.

[0043] A stepped self-cleaning filter assembly 9 is installed at the front end of the housing 1 and at the flange connection position of the flue gas inlet pipe 3. The stepped self-cleaning filter assembly 9 is a pre-dust interception module. Before the high-temperature and high-sulfur flue gas enters the heat exchange chamber of the housing, it passes through a stepped filtration to pre-intercept coarse and fine dust particles in the flue gas. This reduces the direct impact and wear of large fly ash particles on the enamel inner wall of the housing, the S-shaped continuous bend 4, and the heat exchange fins 15 from the source. It effectively solves the core defects of traditional economizers, such as the lack of a pre-filtration structure, continuous wear of the enamel anti-corrosion layer by dust, and easy blockage and corrosion of the heat exchange pipeline.

[0044] In this embodiment, the cascade self-cleaning filter assembly 9 adopts a modular split design, which can be disassembled, hoisted, and repaired independently without needing to be disassembled as a whole with the housing 1, greatly reducing the workload of equipment operation and maintenance; the cascade self-cleaning filter assembly 9 includes a rectangular cylinder 17, rectangular ear plates 18, and a drain port blocking plate 25; the rectangular cylinder 17 is a vertical hollow cuboid sealed cylinder structure, and the flue gas flows vertically from top to bottom along the inside of the cylinder; the rectangular ear plates 18 are integrally welded to the upper and lower end faces of the rectangular cylinder 17, and there is no splicing gap between the ear plates and the cylinder, preventing the leakage of flue gas; each rectangular ear plate 18 has several through holes 19 evenly opened along the edge of the plate surface, and the specifications and opening spacing of the through holes 19 are completely matched with the through holes 12 at the flange of the flue gas inlet pipe 3, so as to achieve precise alignment and assembly.

[0045] The rectangular ear plate 18 at the upper end of the rectangular cylinder 17 fits against the front flange face of the smoke inlet pipe 3. The bolts pass through the through hole 19 and through hole 12 simultaneously to complete the detachable sealing assembly. A high-temperature resistant flexible sealing gasket is added to the flange mating surface to completely seal the flange gap and prevent smoke leakage. A rectangular ash discharge opening is reserved on the side wall of the rectangular cylinder 17. The opening position is equipped with a discharge port blocking plate 25. The discharge port blocking plate 25 adopts a bolt-tight sealing structure. During the normal filtration operation of the equipment, the ash discharge port is completely closed. Only when it is necessary to clean the ash accumulated at the bottom of the cylinder, the fixing bolts can be removed and the blocking plate 25 can be removed directly to discharge the ash. There is no need to lift and disassemble the rectangular cylinder 17 as a whole, which shortens the downtime for maintenance.

[0046] The inner cavity of the rectangular cylinder 17 is fixed with three layers of rectangular frames 20 along the downward direction of the flue gas. The three layers of rectangular frames are arranged in parallel from top to bottom. Each layer of frames has a slot that clamps and fixes a layer of filter screen 21. The filter screen 21 completely seals the flow section of the cylinder. The flue gas must pass through multiple layers of filter screens completely before it can flow downward into the flue gas inlet pipe 3. The mesh size of the three layers of filter screen 21 gradually decreases from top to bottom along the flue gas flow direction. The upper layer of filter screen has the largest mesh size and prioritizes intercepting large-diameter carbon particles and coarse fly ash in the flue gas. The middle layer of filter screen intercepts medium-diameter dust particles. The bottom layer of fine filter screen captures fine dust, realizing the step-by-step interception of dust, dispersing the filtration load of a single layer of filter screen, slowing down the clogging speed of the filter screen, extending the continuous working time of the filter screen, and reducing the frequency of filter screen cleaning operations.

[0047] A dedicated filter cleaning assembly is fitted to the outside of the rectangular cylinder 17. The cleaning unit is used to remove dust from the surface of the filter screen online without stopping the machine to disassemble the filter screen. The cleaning unit consists of an electric push rod 22, a connecting plate 23, and a high-temperature resistant brush 24. There are three sets of electric push rods 22, which are arranged horizontally and parallel to each other along the outside of the rectangular cylinder. The height of each set corresponds to the three layers of rectangular frames 20, so that one cleaning mechanism is matched with each layer of filter screen. The horizontal output end of each set of electric push rods 22 is fixedly connected to the middle of the connecting plate 23. The connecting plate 23 is horizontally suspended above the corresponding frame. The overall width of the connecting plate is greater than the horizontal dimension of the filter screen to ensure full cleaning coverage. The high-temperature resistant brush 24 is vertically fixed on the lower surface of the connecting plate. The brush bristles are high temperature resistant and wear resistant and will not melt or break under long-term high temperature conditions. The bristles are tightly attached to the upper surface of the filter screen. When the electric push rod 22 moves horizontally, it drives the brush to sweep back and forth along the entire horizontal direction of the filter screen, removing the dust attached to the filter screen pores.

[0048] The rectangular cylinder 17 has a closed cavity below the bottom filter screen, forming a dedicated ash settling area. The dust scraped off by the brush slides down the inclined surface of the filter screen by its own gravity and accumulates in the settling space at the bottom of the cylinder. The dust will not scatter and adhere to the side walls or frame of the cylinder. The filter screen cleaning, dust gravity settling, and concentrated ash discharge on the side walls form a closed loop structure. The filter screen cleaning operation does not need to interrupt the boiler flue gas supply, realizing online ash cleaning without stopping the machine. This solves the problem that traditional filter screens must be stopped and disassembled for manual cleaning, causing boiler feed interruption and production stoppage.

[0049] In this embodiment, the single heat exchange fin 15 is symmetrically arranged with raised plates 16. The raised plates 16 are bent downwards from the edge of the fin plate surface, forming a fixed angle with the main fin plate surface. The two together form an open turbulence gap. During the process of high-temperature flue gas laterally scouring the heat exchange fins, the flow trajectory is forcibly changed after the airflow comes into contact with the tilted raised plates 16. The laminar boundary layer that was originally flowing smoothly attached to the fins is continuously torn and dispersed, generating a large number of small turbulent vortices. The turbulent state greatly improves the contact efficiency between the flue gas and the heat exchange fins and the outer wall of the S-shaped continuous bend tube. Under the same flue gas conditions, the heat exchange efficiency is increased by more than 15% compared with straight fins without raised plates.

[0050] Meanwhile, the downward-sloping surface of the raised plate 16 naturally possesses self-drying ash removal capabilities. Dust particles, after falling onto the sloping surface, cannot accumulate over a large area. Under the combined effects of continuous flue gas impact and their own gravity, they automatically slide down to the bottom of the chamber, reducing the amount of ash adhering to the heat exchange surface from the source, lowering the workload of the online high-pressure soot blowing system, saving the consumption of high-pressure purging media, and extending the service life of the unidirectional high-pressure nozzle and the entire soot blowing equipment. The raised plate 16 is integrally stamped with the heat exchange fins, eliminating welding stress and weld corrosion risks. The boiler remains structurally stable under long-term high-temperature alternating vibration and high-sulfur corrosion environments, significantly reducing the failure rate.

[0051] In this embodiment, four layered connecting boxes 10 are symmetrically assembled on the left and right side walls of the box body 1. The four connecting boxes on the same side are evenly arranged in layers along the vertical height of the box body, respectively corresponding to the heat exchange areas of all S-shaped continuous bends 4 and heat exchange fins 15 in the upper, middle upper, middle lower and lower layers inside the box body. The layered independent arrangement structure can accurately blow the dust in the light and heavy dust areas. The dust settling amount in the lower heat exchange area is large, which can increase the flow rate of the blowing medium. The air supply is reduced in the upper area with lighter dust accumulation, so as to realize the distribution of the medium on demand and reduce energy consumption.

[0052] The two adjacent connection boxes 10 on the same side are sealed and connected by a horizontally arranged connecting pipe 3 11. The two ends of the connecting pipe 3 11 are welded and sealed to the openings on the side walls of the upper and lower connection boxes, ensuring that the pressure of the purging medium inside all connection boxes on the same side is uniform and stable, and there will be no situation of excessive pressure in the upper layer, weak spraying of the bottom nozzle, or incomplete cleaning of accumulated dust.

[0053] The top of the top connecting box 10 on both the left and right sides of the box is independently connected to the cleaning delivery pipe 13. The external high-pressure purging medium is uniformly sent into the top connecting box through the cleaning delivery pipe, and then distributed downwards to all the lower connecting boxes 10 via the connecting pipe 3 11.

[0054] Each connecting box 10 has multiple sets of unidirectional high-pressure nozzles 14 threaded into the tubular end of the heat exchange chamber. The threaded detachable structure makes it easy to replace the nozzles individually after they become clogged or worn, without having to disassemble the entire connecting box. The nozzles are arranged at multiple angles, and the jetting airflow completely covers all heat exchange components on the same side, eliminating any blind spots.

[0055] The one-way high-pressure nozzle 14 integrates a built-in one-way valve structure. The one-way valve only allows the high-pressure cleaning medium to be sprayed into the box in one direction, completely preventing the high-temperature dust-laden flue gas and fine dust inside the box from flowing back into the connecting box 10, connecting pipe 3 11, and cleaning delivery pipe 13. This avoids dust clogging the pipeline and acidic high-temperature flue gas corroding the inner wall of the soot blowing pipeline, and greatly reduces the frequency of soot blowing pipeline maintenance and cleaning.

[0056] Example 1 Multiple S-shaped continuous bends 4 are inserted into the outer wall of one side of the housing 1. The same end of the multiple S-shaped continuous bends 4 is welded to the connecting pipe 1 5. The outer wall of the connecting pipe 1 5 is vertically welded to the inlet pipe 6. The inlet pipe 6 introduces the unheated boiler feedwater at room temperature into the entire economizer heat exchange module. The other end of the multiple S-shaped continuous bends 4 is welded to the connecting pipe 2 7. The outer wall of the connecting pipe 2 7 is vertically welded to the outlet pipe 8. The outlet pipe 8 transports the heated feedwater after absorbing the heat of the flue gas to the boiler drum or downstream waste heat utilization equipment.

[0057] Multiple heat exchange fins 15 are welded and fixed at equal intervals between several S-shaped continuous bends 4. The heat exchange fins 15 are vertically fixed to the outer wall of the bends, which greatly expands the total heat transfer area on the flue gas side and significantly improves the waste heat exchange efficiency of the entire unit. The surfaces of the heat exchange fins 15 and the S-shaped continuous bends 4 are completely coated with a high-temperature resistant and corrosion-resistant enamel coating to resist corrosion from high-sulfur flue gas. The outer walls on both sides of the heat exchange fins 15 are integrally formed with raised plates 16, which are arranged inclined from top to bottom along the flue gas flow direction. When the flue gas flows through the raised plates 16, the original laminar boundary layer is continuously disrupted, forming turbulence to enhance heat exchange. At the same time, the inclined slope prevents dust from spreading and accumulating, and has a passive self-cleaning effect.

[0058] Four connecting boxes 10 are fixed to the outer walls of the left and right sides of the housing 1 with high-strength bolts. One end of the connecting box 10 penetrates the side wall of the housing and extends into the heat exchange cavity of the housing. Multiple sets of one-way high-pressure nozzles 14 are threaded onto the end of the connecting box 10 that extends into the cavity. The one-way high-pressure nozzles 14 can spray high-pressure cleaning media at a preset angle and preset pressure. The high-speed airflow directly impacts the enamel surface of the S-shaped continuous bend 4 and the heat exchange fins 15, peeling off the attached fly ash deposits. The nozzle has a built-in one-way valve structure, which can effectively prevent the backflow of flue gas and dust inside the housing into the external cleaning pipeline system.

[0059] The four connecting boxes 10 arranged from top to bottom on the same side are connected in sequence by horizontal connecting pipe 3 11. Connecting pipe 3 11 enables the exchange of purging media and pressure equalization among all connecting boxes on the same side. The top of the two connecting boxes 10 at the top of the left and right sides of the box are respectively connected to the cleaning delivery pipe 13. The other end of the cleaning delivery pipe 13 is connected to the workshop high-pressure medium generating equipment. High-pressure steam, compressed air and other purging media are stably delivered to the interior of each connecting box 10 through the cleaning delivery pipe 13.

[0060] This embodiment only includes the housing, heat exchange pipelines, heat exchange fins, and a double-sided layered online soot blowing system. Its core functions are to recover waste heat from high-sulfur flue gas and perform high-pressure soot blowing on the heat exchange surface without shutting down the boiler. It relies on the enamel coating to isolate acidic flue gas corrosion, the integrated tilting fins to improve heat exchange efficiency and reduce ash accumulation, and the built-in unidirectional high-pressure nozzles to achieve continuous self-cleaning of the heat exchange surface. It solves the industry problems of traditional enamel economizers, such as ash accumulation covering the heat exchange surface, continuous decline in heat exchange efficiency, and lack of online soot cleaning methods. The entire module can maintain stable heat exchange efficiency under continuous boiler operation and extend the service life of the enamel anti-corrosion coating.

[0061] Example 2 The top of the housing 1 is bolted and sealed with a flue gas inlet pipe 3, which serves as the inlet channel for the pre-filtered high-temperature flue gas, evenly delivering the clean flue gas to the heat exchange area inside the housing. The bottom of the housing is bolted and sealed with a flue gas outlet pipe 2, which is responsible for discharging the low-temperature flue gas after heat exchange and purging and ash removal to the boiler's back-end desulfurization, denitrification, and dust removal system. Four sets of through holes 12 are equidistantly opened on the flanges at the outer ends of the flue gas inlet pipe 3 and the flue gas outlet pipe 2. Bolts are used to seal the flue gas inlet pipe 3 to the cascade self-cleaning filter assembly 9.

[0062] The top flange of the flue pipe 3 is bolted to fix the stepped self-cleaning filter assembly 9. The main body of the filter module is a rectangular cylinder 17. The side wall of the rectangular cylinder 17 is reserved with an ash discharge opening. The discharge port blocking plate 25 can be installed at the opening with detachable bolts. The discharge port blocking plate 25 is a sealing cover for the ash hopper of the cylinder. During normal operation of the equipment, it is sealed to prevent flue gas leakage. When cleaning the ash, the blocking plate can be removed to discharge the ash accumulated at the bottom of the cylinder.

[0063] The inner cavity of the rectangular cylinder 17 is bolted with three layers of rectangular frames 20 in a vertical direction. Each layer of rectangular frame 20 is equipped with a filter screen 21. The mesh size of the three layers of filter screen 21 gradually decreases from top to bottom, so as to achieve layered interception of large, medium and fine fly ash in the flue gas, disperse the filtration load of a single filter screen, and slow down the clogging speed of the filter screen.

[0064] Three electric push rods 22 are horizontally bolted to the outer wall of the rectangular cylinder 17 on one side of the drain outlet blocking plate 25. The electric push rods are preferably THK standard linear push rods. The output ends of the three electric push rods 22 are respectively fixed to connecting plates 23. The three connecting plates are respectively suspended above the three-layer rectangular frame 20. The bottom of the connecting plates is vertically bolted to high-temperature resistant brushes 24. The bristles of the three sets of high-temperature resistant brushes 24 are tightly attached to the surface of the corresponding layer of filter screen 21. The electric push rods drive the brushes to move horizontally back and forth, scraping away the ash and slag blocking the filter screen pores. The detached dust settles to the ash accumulation area at the bottom of the cylinder by gravity. Rectangular ear plates 18 are integrally welded to the outer walls of the upper and lower ends of the rectangular cylinder 17. Four sets of through holes 19 are equally spaced on the surface of the rectangular ear plates 18. The size and spacing of the through holes 19 are completely matched with the through hole 12 of the flange of the smoke inlet pipe 3. The bolts pass through the two types of through holes simultaneously to achieve a detachable and sealed assembly between the rectangular cylinder 17 and the smoke inlet pipe 3. A high-temperature resistant sealing gasket is added to the flange mating surface to prevent smoke leakage.

[0065] This embodiment, based on the existing heat exchange and online soot blowing functions, adds a pre-filter structure with three-stage self-cleaning filtration. Before the high-temperature, high-dust flue gas enters the heat exchange chamber, most of the dust is pre-filtered out, reducing the erosion and wear of the enamel heat exchange surface by dust at the source. The electric push rod drives the high-temperature brush to achieve online cleaning of the filter screen without stopping the machine. After the dust settles, it is quickly discharged through the side wall blockage plate. The entire device simultaneously achieves three core functions: pre-dust removal of flue gas, efficient waste heat recovery, and online soot blowing of heat exchange surfaces. It is suitable for long-term uninterrupted continuous operation of low-quality coal-fired boilers with high sulfur, high dust, and high humidity. The modular flange assembly structure greatly reduces the difficulty of equipment installation, maintenance, and replacement.

[0066] A second aspect of the present invention provides a method for flue gas heat exchange and self-cleaning operation based on a high-sulfur coal enamel economizer device with self-cleaning filter and online soot blowing as described above, comprising: The boiler burns high-sulfur coal, producing high-temperature, high-sulfur, and high-dust-content flue gas. This flue gas is first transported along the flue to the stepped self-cleaning filter assembly 9 connected at the top of the inlet pipe 3. The flue gas then flows vertically downwards into the rectangular cylinder 17, passing through three layers of filter screens 21 with progressively smaller mesh sizes from top to bottom. The upper layer, with its large pores, preferentially traps coarse carbon particles and fly ash; the middle layer captures medium-sized dust particles; and the bottom layer, with its fine mesh, removes fine dust. This three-stage interception significantly reduces the dust content of the flue gas entering the heat exchange chamber, minimizing wear caused by dust erosion of the enamel heat exchange components. After long-term continuous filtration, dust will accumulate in the pores of the filter screen. During the boiler's non-stop operation, three electric push rods 22 can be started periodically. The electric push rods drive the connecting plate 23 and the high-temperature resistant brush 24 to sweep horizontally back and forth along the surface of the corresponding layer of filter screen 21, peeling off the ash and slag attached to the filter screen surface. The fallen dust slides down the inclined mesh surface of the filter screen under the action of gravity and accumulates in the ash settling area at the bottom of the rectangular cylinder 17. Only when the boiler is scheduled to be shut down for short-term maintenance can the drain port blockage plate 25 be removed, the accumulated ash and slag at the bottom of the cylinder be cleaned, and the blockage plate be reset to restore the sealing and filtration operation.

[0067] After undergoing three-stage pre-filtration, the clean, high-temperature flue gas is smoothly introduced into the heat exchange chamber in the middle of the housing 1 through the flue gas inlet pipe 3. The flue gas evenly flows laterally over multiple S-shaped continuous bends 4 and heat exchange fins 15 equidistantly welded to the outer wall of the bends. The heat exchange fins 15 have integrally formed downward-sloping raised plates 16 on both sides. When the flue gas comes into contact with the raised plates, the original stable laminar boundary layer is torn apart and dispersed, generating a large number of turbulent vortices, which greatly improves the heat exchange efficiency between the flue gas and the heat exchange components. At the same time, the inclined slope of the raised plates prevents dust from spreading and adhering to the fin surface, achieving passive self-dust removal. Boiler feedwater at ambient temperature is sent into connecting pipe 5 through inlet pipe 6 and evenly distributed into each S-shaped continuous bend pipe 4. The feedwater flows continuously in the meandering S-shaped continuous bend pipe, fully absorbing the waste heat carried by the high-temperature flue gas on the outside of the pipe wall. The heated circulating feedwater is collected in connecting pipe 7 and transported to waste heat utilization equipment such as boiler drum and heating system through outlet pipe 8 to complete the flue gas waste heat recovery process.

[0068] During continuous heat exchange operation, the online soot blowing components symmetrically arranged on both sides of the housing 1 are automatically activated according to the preset operating cycle and heat exchange efficiency monitoring feedback signal. High-pressure steam or compressed air output from the workshop high-pressure medium generator is sent to the top-level connecting boxes 10 on both sides of the housing via the clean delivery pipe 13. The high-pressure medium is evenly distributed to the interior of the four-layer connecting boxes 10 on the same side through the horizontally arranged connecting pipe three 11. The medium is directionally and rapidly sprayed through the one-way high-pressure nozzles 14 threaded at the end of the connecting boxes. The high-pressure airflow powerfully impacts the surface of the S-shaped continuous bend pipe 4 and the heat exchange fins 15, peeling off loose and slightly adhered ash deposits. The one-way high-pressure nozzles 14 have a built-in one-way valve structure that completely blocks the backflow of high-temperature dusty flue gas and fine dust from inside the housing into the connecting boxes 10, connecting pipe three 11, and clean delivery pipe 13, preventing blockage of the soot blowing pipeline and corrosion of the pipeline by acidic flue gas, ensuring long-term stable and trouble-free operation of the soot blowing system.

[0069] After pre-filtration, waste heat recovery, and online high-pressure purging for ash removal, the low-temperature, low-dust flue gas continuously gathers downwards to the bottom outlet area of ​​housing 1. It is then uniformly discharged outwards through the outlet pipe 2 and transported to the boiler's downstream integrated deep flue gas treatment system, which includes desulfurization, denitrification, and baghouse dust collection. This completes the entire closed-loop cycle of flue gas filtration, heat exchange, and self-cleaning. The entire process allows for uninterrupted continuous boiler production without frequent shutdowns to disassemble and clean filter screens and heat exchange fins, significantly reducing the probability of boiler downtime and production failures. It is perfectly suited for the harsh flue gas conditions of long-term combustion of high-sulfur, high-dust, and high-humidity low-quality coal.

[0070] From the perspective of assembly structure, the housing 1, the inlet pipe 3, the outlet pipe 2, and the cascade self-cleaning filter assembly 9 all adopt a detachable assembly structure with flange bolts. Each independent functional unit can be manufactured, transported, hoisted, and inspected and replaced separately without the need to disassemble the entire economizer device. When a part of the equipment is damaged, only the corresponding module needs to be replaced, which greatly reduces the difficulty of on-site construction and installation and the cost of subsequent equipment maintenance, and avoids the defects of transportation and maintenance difficulties of integrated large welded shells.

[0071] The tiered self-cleaning filter assembly 9 relies on a three-layer gradient pore size filter screen to achieve graded interception of coarse and fine dust. It is equipped with an electric push rod to drive a high-temperature resistant brush to achieve online automatic cleaning of the filter screen without stopping the machine. After the dust settles by gravity, it can be quickly and centrally discharged through the blockage plate of the side wall discharge port, which greatly reduces the dust content entering the heat exchange chamber from the source. It also reduces the continuous erosion and wear of the enamel inner wall of the box, the S-shaped continuous bend 4, and the heat exchange fins 15 by large particles of fly ash, effectively extending the service life of the enamel anti-corrosion coating and the overall service life of the heat exchange pipeline.

[0072] The central heat exchange module adopts an S-shaped continuous integrated bend tube combined with a heat exchange fin combination structure with an integrated inclined raised plate. The turbulence generated by the turbulence formed by the raised plate changes the flow state of the flue gas and generates turbulence, which significantly improves the heat exchange efficiency of waste heat recovery. At the same time, the inclined slope has a passive self-ash removal effect, which reduces the total amount of ash adhering to the heat exchange surface, reduces the operating load of the online high-pressure soot blowing system, saves the consumption of high-pressure purging medium, and reduces the frequency of start-up and shutdown of soot blowing equipment.

[0073] The box body is symmetrically arranged with layered online soot blowing components on both sides. The four-layer connecting boxes on each side are evenly arranged along the height of the box body, and are equipped with full-coverage multi-angle unidirectional high-pressure nozzles to completely eliminate dead corners in the heat exchange area. The connecting boxes on the same side are connected by horizontal connecting pipes in a 3:11 manner to ensure uniform and stable pressure of the blowing medium. The nozzles have built-in one-way valve structures, which completely solves the problems of backflow and blockage of flue gas and dust in traditional soot blowing pipelines, as well as pipeline corrosion and damage. The high-pressure soot blowing operation does not require shutdown and interruption of boiler flue gas supply, and realizes continuous automatic soot cleaning of the heat exchange surface.

[0074] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A high-sulfur coal enamel economizer device with self-cleaning filter and online soot blowing, characterized in that, include: The housing has a smoke inlet channel and a smoke outlet channel connected to both ends, and the inner wall of the housing is lined with an enamel heat exchange surface. The heat exchange assembly is arranged inside the housing. The heat exchange assembly includes an S-shaped continuous bend and heat exchange fins. The two ends of the S-shaped continuous bend are respectively connected to the water inlet pipe and the water collection pipe. The heat exchange fins are fixed to the outer wall of the S-shaped continuous bend at equal intervals. The two sides of the heat exchange fins are integrally stamped and formed, with the fins tilted from top to bottom along the flue gas flow direction. An online soot blowing assembly is symmetrically fixed to the side wall of the housing. The online soot blowing assembly includes a connecting box and a one-way high-pressure nozzle. The connecting boxes are interconnected by pipelines. The top of the upper connecting box is connected to a cleaning delivery pipe. The inner side of the connecting box penetrates the side wall of the housing and extends into the inner cavity of the housing. The one-way high-pressure nozzle is threadedly assembled to the end of the connecting box located in the inner cavity. The spray end of the one-way high-pressure nozzle faces the S-shaped continuous bend and heat exchange fins. A tiered self-cleaning filter assembly is installed at the front end of the smoke inlet channel to pre-intercept dust particles inside the smoke.

2. The high-sulfur coal enamel economizer device with self-cleaning filter and online soot blowing according to claim 1, characterized in that, The cascade self-cleaning filter assembly includes: Rectangular cylindrical body, rectangular ear plate, and drain outlet blocking plate; The rectangular ear plate is integrally welded to both ends of the rectangular cylinder, and several through holes are evenly provided on the rectangular ear plate; The top flange face of the smoke inlet channel is provided with a through hole one that matches through hole two. The rectangular cylinder is detachably and sealed to the front end of the smoke inlet channel by bolts passing through through hole two and through hole one. The drain plug plate is detachably mounted on the side wall of the rectangular cylinder.

3. The high-sulfur coal enamel economizer device with self-cleaning filter and online soot blowing according to claim 2, characterized in that, The interior of the rectangular cylindrical body includes: Three-layer rectangular frame and filter screen; The three-layer rectangular frame is fixed in layers inside the rectangular cylinder along the downward direction of the flue gas, and each layer of the rectangular frame is equipped with a filter screen. The three-layer filter screen has a progressively smaller mesh size from top to bottom along the flue gas flow direction, which is used to achieve tiered and layered interception of flue gas dust.

4. The high-sulfur coal enamel economizer device with self-cleaning filter and online soot blowing according to claim 3, characterized in that, The filter cleaning assembly includes: Electric actuator, connecting plate and brush; The output end of the electric push rod is fixedly connected to the connecting plate, and the brush is vertically assembled at the bottom of the connecting plate. The electric push rod is provided in three sets, and the three sets of electric push rods are arranged along the outside of the rectangular cylinder. The connecting plate connected to each electric push rod is suspended above the first layer of rectangular frame. The bristles of the brush adhere to the surface of the corresponding filter layer, allowing for repeated sweeping of accumulated dust along the filter.

5. The high-sulfur coal enamel economizer device with self-cleaning filter and online soot blowing according to claim 4, characterized in that, A dust accumulation and settling area is formed at the bottom of the rectangular cylinder; The electric push rod drives the connecting plate and the brush to move horizontally and reciprocally in sync. The brush scrapes the dust on the surface of the filter screen, and the dust settles down along the slope of the filter screen into the dust settling area, so as to realize the filter screen cleaning online without stopping the machine.

6. The high-sulfur coal enamel economizer device with self-cleaning filter and online soot blowing according to claim 1, characterized in that, The raised fins are arranged inclined from top to bottom along the flue gas flow direction and surround the heat exchange fins to form a turbulence gap; When flue gas flows, the raised plate can continuously tear the laminar boundary layer of flue gas to form turbulence, and the inclined slope of the raised plate can prevent dust from spreading and accumulating.

7. The high-sulfur coal enamel economizer device with self-cleaning filter and online soot blowing according to claim 1, characterized in that, The left and right side walls of the box are each fixed with four connecting boxes by bolts. The four connecting boxes on the same side are arranged in layers at equal intervals along the height of the box. Each connecting box has multiple sets of unidirectional high-pressure nozzles threaded onto its end that extends into the inner cavity of the box.

8. The high-sulfur coal enamel economizer device with self-cleaning filter and online soot blowing according to claim 7, characterized in that, The connecting boxes arranged on the same side in layers are connected sequentially by three horizontally set connecting pipes; The top of the connecting boxes on both sides of the box body is connected to a cleaning delivery pipe. The one-way high-pressure nozzle is equipped with a one-way valve structure inside. The one-way valve structure is used to spray high-pressure cleaning medium outward to prevent flue gas and dust inside the box from flowing back into the connecting box and the cleaning delivery pipe.

9. The high-sulfur coal enamel economizer device with self-cleaning filter and online soot blowing according to claim 1, characterized in that, Also includes: Smoke inlet pipe and smoke outlet pipe; The smoke inlet pipe is located at the top of the housing, and the housing forms the smoke inlet channel through the smoke inlet pipe; The smoke outlet pipe is located at the bottom of the box, and the box forms the smoke outlet channel through the smoke outlet pipe.

10. A method for flue gas heat exchange and self-cleaning operation based on the high-sulfur coal enamel economizer device with self-cleaning filter and online soot blowing as described in any one of claims 1 to 9, characterized in that, include: S1. High-temperature and high-sulfur flue gas is introduced into the stepped self-cleaning filter component through the flue gas inlet pipe. The flue gas passes through multiple layers of filter screens with progressively smaller mesh sizes from top to bottom, completing the graded interception of dust particles of different sizes. The brush driven by the electric push rod reciprocates to clean the dust on the surface of the filter screen. The dust settles to the dust accumulation area at the bottom of the rectangular cylinder. The discharge port blockage plate is disassembled periodically to collect and discharge the accumulated dust. S2. The filtered flue gas enters the interior of the box along the flue gas inlet channel, and laterally washes the S-shaped continuous bend and heat exchange fins. The raised fins tear the laminar boundary layer of the flue gas to form turbulence and enhance heat exchange. The boiler feedwater is introduced into the S-shaped continuous bend through the water inlet pipe. After the medium inside the pipe absorbs the heat of the flue gas, it is collected in the water collection pipe and transported outward. S3. During the heat exchange process, the online soot blowing component is started periodically. The high-pressure cleaning medium is sent into the layered connection box through the cleaning delivery pipe. It is then sprayed directionally by the one-way high-pressure nozzle onto the S-shaped continuous bend and the enamel surface of the heat exchange fins to peel off the attached ash. The one-way valve structure prevents the flue gas and dust in the box from flowing back into the soot blowing pipeline. S4. The low-temperature flue gas after heat exchange and dust removal is discharged to the subsequent flue gas treatment system through the flue gas outlet pipe at the bottom of the box.

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