Energy-saving boiler

Abstract

The application discloses an energy-saving boiler and relates to the technical field of boilers. The energy-saving boiler comprises a boiler body, a flue gas discharging pipeline installed on the boiler body, an air preheater installed at the end of the flue gas discharging pipeline, a pair of heat exchange pipe groups distributed along the flue gas discharging direction in the air preheater, a plurality of heat exchange pipe bundles, diameter expansion portions and diameter reduction portions alternately distributed along the axis of the heat exchange pipe bundles, helical guide vanes arranged on the inner wall of the diameter reduction portions, a moving cleaning frame with an upper opening and a lower opening, and annular cleaning spoiler pieces corresponding to the heat exchange pipe bundles. The moving cleaning frame and the plurality of annular cleaning spoiler pieces inside the moving cleaning frame can continuously scrape the outer wall of the heat exchange pipe bundle during the moving process. Compared with the traditional blowing ash method, the mechanical scraping method can achieve more thorough ash removal.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of boilers, in particular to an energy-saving boiler. BACKGROUND

[0002] Biomass boiler is the core heat energy equipment in industrial production and heating system, its thermal efficiency directly affects energy consumption and operating cost, and exhaust gas heat loss is one of the main heat losses of the boiler, in order to recover the waste heat in the flue gas, realize energy saving and reduce the exhaust gas temperature, usually install air preheater at the tail of the boiler, the air preheater exchanges heat between flue gas and combustion air, the preheated air enters the furnace, which not only improves the thermal efficiency of the boiler, but also improves the combustion conditions of the fuel.

[0003] The existing patent application with the patent publication number CN118463214A and the publication date of August 9, 2024 is entitled "An industrial boiler anti-ash pipe type air preheater", which includes a preheater hot section formed by a plurality of hot section heat exchange tube bundles at the upper part and a preheater cold section formed by a plurality of cold section heat exchange tube bundles at the lower part of the preheater hot section, and further includes a hot section steam soot blower, the soot blowing pipe of the hot section steam soot blower is arranged at the inlet flue duct at the upper part of the preheater hot section; a sandwich section between the preheater hot section and the preheater cold section; a sandwich steam soot blower, the soot blowing pipe of the sandwich steam soot blower is arranged at the sandwich section; a cold section steam soot blower, the soot blowing pipe of the cold section steam soot blower is arranged at the outlet flue duct at the lower part of the preheater cold section; the cold section heat exchange tube bundles of adjacent layers are arranged in staggered arrangement. The invention sets the sandwich steam soot blower through the sandwich section and arranges the cold section heat exchange tube bundles in staggered arrangement, which avoids the bridging of the preheater cold section ash, shortens the steam soot blowing path, and realizes precise ash blowing.

[0004] The above-mentioned application has the following deficiencies: since the ash content in the boiler flue gas is relatively high, when using flue gas and air for heat exchange, the ordinary boiler air preheater is prone to ash accumulation, and even coal ash blockage, which hinders the flue gas to flow smoothly. Although the ash accumulation between the air preheater tubes can be further blown away by increasing the blowing device, due to the limitations of the blowing device, the gas flow coverage range is restricted by the complex structure of the tube bundle gap, the blowing gas flow has insufficient penetration in the dense tube bundle, and it is difficult to effectively blow away the accumulated ash from the air preheater tube gap. Secondly, continuous high-pressure blowing will cause the tube bundle to vibrate more intensively, accelerate metal fatigue and possibly cause the heat exchange tube and tube plate weld to crack. Furthermore, when the blowing device is used for high-viscosity ash, the high-viscosity ash has stronger adhesion and is not easily removed by the blowing gas flow, resulting in more limited ash removal effect, insufficient heat exchange efficiency of the flue gas, and insufficient utilization of waste heat. SUMMARY

[0005] The purpose of the present application is to provide an energy-saving boiler to solve the above-mentioned deficiencies in the prior art.

[0006] To achieve the above object, the present application provides the following technical solutions:

[0007] The energy-saving boiler comprises a boiler body, a flue gas pipeline mounted on the boiler body, and an air preheater mounted at the end of the flue gas pipeline, wherein a pair of heat exchange pipe groups are arranged in the air preheater along the flue gas discharge direction, each heat exchange pipe group is composed of a plurality of heat exchange pipe bundles, each heat exchange pipe bundle is provided with a diameter expansion part and a diameter reduction part which are alternately arranged along the axis of the heat exchange pipe bundle, the inner wall of the diameter reduction part is provided with a spiral guide vane, a movable cleaning frame with an upper opening and a lower opening is movably mounted in the heat exchange pipe group and is provided with a through hole through which the heat exchange pipe bundle passes, an annular cleaning spoiler corresponding to each heat exchange pipe bundle is rotatably mounted in the movable cleaning frame, the annular cleaning spoiler is in contact with the outer wall of the diameter expansion part and the diameter reduction part, respectively, and the annular cleaning spoiler alternately scrapes the outer wall of the diameter expansion part and the diameter reduction part when the movable cleaning frame moves and rotates under the push of the flue gas to play a spoiler role.

[0008] Preferably, the air preheater is provided with a flue gas inlet connected with the flue gas pipeline at one side of the bottom, is provided with a flue gas outlet at the top, and is provided with an air inlet and an air outlet connected with the two heat exchange pipe groups, respectively, at the other side of the air preheater, and is provided with a reversing air chamber for connecting the two heat exchange pipe groups.

[0009] Preferably, the heat exchange pipe group is fixedly connected with a tube plate at both sides, the heat exchange pipe bundle is fixedly connected with the two tube plates at both ends, respectively, and the air preheater is fixedly connected with a support frame inside.

[0010] Preferably, a double-shaft motor is fixedly connected between the two movable cleaning frames, a transmission rod is mounted at both ends of the double-shaft motor, a driving gear is fixedly connected to the end of the transmission rod, and a rack is fixedly connected to the inner wall of the support frame at both sides and engaged with the bottom of the driving gear.

[0011] Preferably, the annular cleaning spoiler comprises a cleaning sleeve rotatably connected to the inner wall of the movable cleaning frame at both sides, a plurality of blades are annularly arranged on the outer wall of the cleaning sleeve, a resilient scraper is movably inserted into the inner wall of the cleaning sleeve, and abutting inclined grooves are arranged on both sides of the resilient scraper and abut against the diameter reduction part.

[0012] Preferably, a plurality of ash discharge holes are annularly arranged on the cleaning sleeve, and the ash discharge holes are staggered with the blades.

[0013] Preferably, two pull rods are vertically and slidingly installed on both sides of the inner wall of the mobile cleaning frame, a plurality of abutting blocks are vertically distributed on the pull rods, a plurality of accommodating grooves are formed in the side wall of the mobile cleaning frame and are in abutting cooperation with the abutting blocks, a plug-in column is fixedly connected to the middle of the pull rod, and wave-shaped guide grooves are horizontally formed on both sides of the support frame and are used for inserting the plug-in column.

[0014] Preferably, a flow guide inclined plate is fixedly connected to one side of the support frame in the reversing air chamber, an impeller and a spoiler are rotatably installed inside the reversing air chamber below the flow guide inclined plate, eccentric shafts are installed at both ends of the impeller, and connecting rods are hingedly connected to both ends of the spoiler and the eccentric shafts.

[0015] Preferably, an ash hopper is arranged at the bottom of the air preheater, a smoke dust filter screen is installed at the top of the ash hopper, ash discharge grooves are formed in both sides of the smoke dust filter screen, one of the mobile cleaning frames abuts against the smoke dust filter screen, and dust removal brushes are embedded in the side wall of the mobile cleaning frame.

[0016] Preferably, heat-conducting metal wires are embedded between the spiral flow guide pieces and the heat exchange tube bundles.

[0017] In the above technical solution, the mobile cleaning frame and the plurality of annular cleaning spoilers inside the mobile cleaning frame are arranged, so that the heat exchange tube bundles can be continuously scraped during movement. The mechanical scraping method can clean dust more completely than the traditional blowing method, and can effectively remove dust with strong adhesion. The process can be automatically performed during the operation of the boiler without shutdown, thereby ensuring long-period and high-efficiency operation of the equipment. The problem of efficiency reduction and blockage caused by dust accumulation is fundamentally solved. The annular cleaning spoiler rotates under the push of flue gas, and is a high-efficiency spoiler itself. The annular cleaning spoiler not only plays a role in cleaning the tube wall, but also continuously destroys the laminar boundary layer of the heat exchange tube wall to enhance the degree of turbulent flow on the flue gas side, thereby greatly strengthening the heat transfer effect. The cleaning and heat exchange are coordinated in the process of heat exchange. The heat exchange tube bundles are alternately arranged in the expanded and reduced sections, so that the flow velocity and direction of the flue gas and air are periodically changed, thereby further strengthening the turbulent heat exchange. The spiral flow guide pieces of the reduced section guide the rotation of air in the heat exchange tube bundle, thereby further improving the heat exchange coefficient.

[0018] It should be understood that the foregoing general description and the following detailed description are only exemplary and illustrative, but not for limiting the present disclosure.

[0019] The present application file provides an overview of various implementations or examples of the technology described in the present disclosure, and is not a comprehensive disclosure of the full scope or all features of the disclosed technology. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to make the technical solutions in the embodiments of the present application or the prior art clearer, the accompanying drawings needed in the embodiments will be briefly introduced. Obviously, the accompanying drawings in the following description only show some embodiments of the present application, and other drawings can also be obtained by those skilled in the art based on these drawings.

[0021] Figure 1 A whole arrangement plan of the energy-saving boiler of the present application;

[0022] Figure 2 A connection schematic diagram of the exhaust pipe and the air preheater in the energy-saving boiler of the present application;

[0023] Figure 3 A structure schematic diagram of the air preheater in the energy-saving boiler of the present application;

[0024] Figure 4 An internal structure schematic diagram of the air preheater in the energy-saving boiler of the present application;

[0025] Figure 5 A connection schematic diagram of the heat exchange pipe group and the moving cleaning frame in the energy-saving boiler of the present application;

[0026] Figure 6 A partial sectional view of the heat exchange pipe bundle in the energy-saving boiler of the present application;

[0027] Figure 7 A structure schematic diagram of the moving cleaning frame and the supporting frame in the energy-saving boiler of the present application;

[0028] Figure 8 A transmission schematic diagram of the impeller and the spoiler in the energy-saving boiler of the present application;

[0029] Figure 9 A transmission schematic diagram of the annular cleaning spoiler in the energy-saving boiler of the present application.

[0030] Explanation of reference signs:

[0031] 1, boiler body; 101, flue gas duct; 2, air preheater; 201, flue gas inlet; 202, flue gas outlet; 203, air inlet; 204, air outlet; 205, reversing air chamber; 3, heat exchange tube group; 301, heat exchange tube bundle; 302, diameter expansion part; 303, diameter reduction part; 304, spiral guide vane; 305, tube sheet; 306, heat-conducting wire; 4, moving cleaning frame; 401, through hole; 402, double-shaft motor; 403, transmission rod; 404, drive gear; 405, containing groove; 406, dust removal brush; 5, annular cleaning spoiler; 501, cleaning sleeve; 502, blade; 503, elastic scraper; 504, abutting chute; 505, ash discharge hole; 6, support frame; 601, rack; 602, undulating guide groove; 603, guide inclined plate; 7, pull rod; 701, abutting block; 702, plug-in column; 8, impeller; 801, eccentric shaft; 9, spoiler; 901, connecting rod; 10, ash hopper; 11, dust filter screen; 12, ash discharge groove. DETAILED DESCRIPTION

[0032] To make the objectives, technical solutions and advantages of the embodiments of the present disclosure clearer, the technical solutions of the embodiments of the present disclosure will be described clearly and completely below with reference to the drawings of the embodiments of the present disclosure. Obviously, the described embodiments are some but not all of the embodiments of the present disclosure. Based on the described embodiments of the present disclosure, all other embodiments obtained by those of ordinary skill in the art without creative effort belong to the scope of protection of the present disclosure.

[0033] Please refer to Figures 1-9 The energy-saving boiler provided by the embodiments of the present disclosure comprises a boiler body 1 and a flue gas duct 101 installed on the boiler body 1, further comprises an air preheater 2 installed at the end of the flue gas duct 101, and a pair of heat exchange tube groups 3 distributed along the flue gas discharge direction are installed in the air preheater 2. The heat exchange tube group 3 is composed of a plurality of heat exchange tube bundles 301, and the heat exchange tube bundle 301 is provided with a diameter expansion part 302 and a diameter reduction part 303 alternately distributed along the axis thereof. The inner wall of the diameter reduction part 303 is provided with a spiral guide vane 304. A moving cleaning frame 4 with an upper opening and a lower opening is movably installed in the heat exchange tube group 3, and the moving cleaning frame 4 is provided with a through hole 401 through which the heat exchange tube bundle 301 passes. A rotating annular cleaning spoiler 5 corresponding to each heat exchange tube bundle 301 is rotatably installed in the moving cleaning frame 4. The annular cleaning spoiler 5 is in contact with the outer wall of the diameter expansion part 302 and the diameter reduction part 303, respectively. When the moving cleaning frame 4 moves, the annular cleaning spoiler 5 alternately scrapes the outer wall of the diameter expansion part 302 and the diameter reduction part 303, and rotates to play a spoiler role under the push of the flue gas.

[0034] Specifically, the biomass bulk material is crushed by the first feeding workshop, then transferred to the second feeding workshop, and then sent to the gasification furnace by the feeding belt. The intermediate transfer warehouse is responsible for the average distribution of biomass to two gasification furnaces. Biomass pyrolysis in the gasification furnace produces biomass gas. The biomass gas is sucked into the boiler burner by the gas induced draft fan and mixed with the air delivered by the air blower for combustion. The flue gas after combustion is discharged to the tail flue. The tail flue is equipped with an economizer and an air preheater. A pair of heat exchange pipe groups 3 are installed in the air preheater 2 along the direction of the flue gas flow. Each heat exchange pipe group 3 is composed of a plurality of parallel heat exchange pipe bundles 301. The heat exchange pipe bundle 301 is used for the flow of cold air, and its pipe wall acts as a heat transfer surface to exchange heat with the high-temperature flue gas in the flue gas duct 101. In order to strengthen heat transfer and optimize flow characteristics, the outer wall of the heat exchange pipe bundle 301 is alternately distributed with expansion sections 302 and contraction sections 303 along its axis. This alternating pipe diameter design causes the cross section of the flue gas flow path passing through the outside to change periodically, effectively destroying the laminar boundary layer of the flue gas, enhancing the turbulent flow effect, and improving the heat exchange efficiency. At the same time, a spiral guide vane 304 is arranged on the inner wall of the contraction section 303. When the air flows through the contraction section 303, the spiral guide vane 304 can guide the air to produce a swirling flow, further strengthening the convective heat transfer coefficient in the pipe. The moving cleaning frame 4 is movably installed in the shell of the air preheater 2 and can move back and forth along the distribution direction of the heat exchange pipe group 3 under the action of the driving member. The moving cleaning frame 4 is provided with through holes 401 corresponding to the number and position of the heat exchange pipe bundles 301, so that the moving cleaning frame 4 can be sleeved on the entire row of heat exchange pipe bundles 301 and can move along them. When the moving cleaning frame 4 moves left and right under the action of the driving mechanism, it drives all the annular cleaning spoiler members 5 to move together. Since the inner ring surface of the annular cleaning spoiler member 5 is always in contact with the outer wall of the heat exchange pipe bundle 301, it continuously scrapes the pipe wall during movement. This mechanical scraping cleaning method is more direct and powerful than traditional steam blowing or acoustic blowing, and can effectively remove various deposits including strongly adhering dust, making the dust removal more thorough. This dust removal process can be automatically completed during normal operation of the boiler without the need for shutdown, greatly ensuring the continuity of equipment operation and the stability of thermal efficiency, and fundamentally solving the problems of heat exchange efficiency reduction and flow passage blockage caused by dust accumulation. During the operation of the boiler, the high-temperature flue gas continuously flows through the heat exchange pipe bundle 301, and the flue gas flow will generate a force on the annular cleaning spoiler member 5, pushing it to rotate around the axis of the heat exchange pipe bundle 301. The rotating annular cleaning spoiler member 5 itself constitutes an efficient spoiler, which not only cleans the pipe wall, but also constantly and dynamically disturbs the flue gas flowing around it, strongly destroying the laminar boundary layer on the surface of the heat exchange pipe wall, significantly enhancing the degree of turbulent flow on the flue gas side, and directly bringing about a substantial increase in the convective heat transfer coefficient between the flue gas and the pipe wall, thereby strengthening the heat transfer effect. The dust removal and flow disturbance strengthening heat transfer processes are dynamically combined together.The dust is cleaned and heat exchange is realized simultaneously.

[0035] Compared with the prior art, the embodiment of the present application sets the moving cleaning frame 4 and the plurality of annular cleaning spoilers 5 inside the moving cleaning frame 4, so that the outer wall of the heat exchange tube bundle 301 can be continuously scraped during the moving process. The mechanical scraping method can clean the dust more thoroughly than the traditional blowing method, especially can effectively remove the dust with strong adhesion. The process can be automatically performed during the operation of the boiler, without shutdown, so that the long-period and high-efficiency operation of the equipment is ensured. The problem of efficiency reduction and blockage caused by the dust is fundamentally solved. The annular cleaning spoiler 5 rotates under the push of the flue gas, and the annular cleaning spoiler 5 itself is a high-efficiency spoiler. The annular cleaning spoiler 5 not only plays a role in cleaning the tube wall, but also continuously destroys the laminar boundary layer of the heat exchange tube wall, so that the turbulence degree of the flue gas side is enhanced, and the heat transfer effect is greatly strengthened. The dust is cleaned and heat exchange is realized simultaneously. The dust is cleaned in the heat exchange, and the synergy effect is achieved. The expansion section 302 and the reduction section 303 of the heat exchange tube bundle 301 are arranged alternately, so that the flow speed and direction of the flue gas and the air are periodically changed, and the turbulent heat exchange is further strengthened. The expansion section 302 provides an expansion space for the flue gas, which helps to reduce the overall pressure loss. The spiral guide vane 304 of the reduction section 303 guides the air to rotate in the heat exchange tube bundle 301, and the heat exchange coefficient is further improved.

[0036] In a further embodiment of the present application, the air preheater 2 is provided with a flue gas inlet 201 connected with the flue gas duct 101 at one side of the bottom, and a flue gas outlet 202 at the top, a pair of heat exchange tube groups 3 are arranged in the air preheater 2 in an up-down distribution, and the air preheater 2 is provided with an air inlet 203 and an air outlet 204 at the other side, which are respectively connected with the two heat exchange tube groups 3, and the air preheater 2 is provided with a reversing air chamber 205 for connecting the two heat exchange tube groups 3. Specifically, the pair of heat exchange tube groups 3 are arranged in an up-down distribution in the air preheater 2, which is beneficial to form a more reasonable air flow channel and temperature distribution. The high-temperature flue gas from the flue gas duct 101 of the boiler body 1 enters the bottom of the air preheater 2 through the flue gas inlet 201, and mainly flows upward in the air preheater 2. Firstly, the flue gas washes the outer wall of the tube bundle of the lower heat exchange tube group 3, and transfers part of the heat to the air in the tube. Then, the flue gas continues to rise and washes the outer wall of the tube bundle of the upper heat exchange tube group 3, and performs a second heat exchange, and the temperature is further reduced. Finally, the cooled flue gas is discharged from the flue gas outlet 202 at the top of the air preheater 2. The cold air enters from the air inlet 203, and firstly enters the tube of the upper heat exchange tube group 3. At this time, the air flow direction is opposite to the overall flow direction of the flue gas. This counter-flow arrangement has the largest average heat transfer temperature difference, and the heat exchange efficiency is high. The air is preliminarily heated when flowing through the upper heat exchange tube group 3. The warm air after the first heating flows out from the outlet of the upper heat exchange tube group 3, enters the reversing air chamber 205, changes the flow direction in the reversing air chamber 205, and is guided to the inlet of the lower heat exchange tube group 3. The warm air enters the tube of the lower heat exchange tube group 3, and continues to absorb the heat of the flue gas. In this stage, after the second heating, the air reaches the predetermined temperature and becomes hot air. Finally, the hot air flows out from the outlet of the upper heat exchange tube group 3, is sent out through the air outlet 204, and is supplied to the boiler burner for use, so as to realize the secondary preheating of the air and achieve the purpose of energy saving.

[0037] In further embodiments of the present application, the heat exchange tube group 3 is fixedly connected with tube plates 305 on both sides, the two ends of the heat exchange tube bundle 301 are fixedly connected with the two tube plates 305 respectively, the air preheater 2 is fixedly connected with a support frame 6 inside, the tube plate 305 is connected with the support frame 6, specifically, the tube plate 305 is processed with tube holes corresponding to the number and position of the heat exchange tube bundle 301 accurately, the two ends of each heat exchange tube bundle 301 are inserted into the tube holes of the two tube plates 305 respectively, and are fixed by welding or expansion joint process, the two tube plates 305 on both sides and all the heat exchange tube bundles 301 together constitute a rigid and modular heat exchange module, the tube plate 305 is connected and fixed with the support frame 6 by bolt connection, the weight and the force borne by the whole heat exchange tube group 3 can be effectively transmitted to the shell of the air preheater 2 through the support frame 6, the spatial position of all the heat exchange tube bundles 301 is relatively fixed, the accurate parallelism and spacing are maintained, the conditions for the moving cleaning frame 4 and the annular cleaning spoiler 5 thereon to move smoothly and without interference along the whole heat exchange tube group 3 are provided, the vibration possibly induced by the flue gas flow is effectively resisted, and the fatigue damage of the tube bundle or the cracking of the connection of the tube plate 305 due to long-term vibration is avoided.

[0038] In a further embodiment of the present application, the two moving cleaning frames 4 are fixedly connected with a double-shaft motor 402, the double-shaft motor 402 is provided with a transmission rod 403 at both ends, the transmission rod 403 is fixedly connected with a drive gear 404 at the end, the support frame 6 is fixedly connected with a rack 601 on the inner wall of both sides, which is engaged with the bottom of the drive gear 404. Specifically, when it is necessary to clean the ash, the double-shaft motor 402 is started, the double-shaft motor 402 synchronously drives the two drive gears 404 to rotate through the transmission rods 403 at both ends, since the drive gears 404 are engaged with the racks 601 fixed on the support frame 6, the rotary motion of the gears will be converted into the linear motion of the entire motor and the moving cleaning frame 4 assembly along the length direction of the rack 601, the design of the double-motor shaft output ensures the absolute synchronization of the two sides of the drive, avoids the torsion or jamming that may be generated by single-point drive, and ensures that the two moving cleaning frames 4 can move together in parallel and stably, so that the scraping force of all annular cleaning disturbance members 5 on the heat exchange tube bundle 301 is uniform, the rigid transmission mode has the characteristics of high transmission efficiency, strong carrying capacity, no slip and the like, it can provide sufficient power to overcome the frictional resistance between the annular cleaning disturbance member 5 and the outer wall of the heat exchange tube bundle 301, and ensure the effective execution of the ash cleaning action, at the same time, the structure itself has good guiding property and position keeping property, the motion trajectory of the moving cleaning frame 4 is strictly limited and cannot be deflected, by controlling the steering and rotating speed of the double-shaft motor 402, the moving direction and moving speed of the moving cleaning frame 4 can be easily controlled, the moving stroke of the cleaning frame can also be accurately controlled through the program or limit switch, ensuring that it can perform full coverage cleaning within the effective length range of the heat exchange tube group 3, the drive mechanism ingeniously uses the existing support frame 6 in the previous embodiment as the installation basis, fixes the rack 601 thereon, without adding additional complex support structure in the preheater shell, so that the design is compact, the support frame 6 itself has high rigidity, providing a stable reference surface for the rack 601, further ensuring the smoothness and accuracy of the transmission.

[0039] In a further embodiment of the present application, the annular cleaning spoiler 5 comprises a cleaning sleeve 501 rotatably connected to both sides of the inner wall of the moving cleaning frame 4, which is rotatably connected to the inner wall of the through hole 401 of the moving cleaning frame 4 through a bearing (not shown in the figure), and a plurality of blades 502 are annularly distributed on the outer wall of the cleaning sleeve 501, and a resilient scraper 503 is movably inserted into the inner wall of the cleaning sleeve 501, and a compression spring is installed between the insertion end of the resilient scraper 503 and the cleaning sleeve 501, and a abutting inclined groove 504 is arranged on both sides of the resilient scraper 503 and abuts against the reduced diameter portion 303, specifically, when the flue gas flows through the heat exchange tube bundle 301, it will impact the blades 502 on the outer wall of the cleaning sleeve 501, and the force of the flue gas will push the entire annular cleaning spoiler 5 to rotate continuously, and the rotating blades 502 and the cleaning sleeve 501 itself are a high-efficiency spoiler unit, which continuously and violently disturbs the flue gas and destroys the laminar boundary layer of the tube wall, greatly strengthening the heat transfer process, when the moving cleaning frame 4 drives the annular cleaning spoiler 5 to move along the heat exchange tube bundle 301, the cleaning sleeve 501 performs dust removal on the surface of the enlarged diameter portion 302 in the heat exchange tube bundle 301, if the cleaning sleeve 501 reaches the reduced diameter portion 303, the resilient scraper 503 will also extend to clean the recessed part under the action of the elastic force, when the moving cleaning frame 4 drives the resilient scraper 503 to move from the reduced diameter portion 303 to the enlarged diameter portion 302, under the guidance and extrusion of the tapered surface between the enlarged diameter portion 302 and the reduced diameter portion 303, the inclined surface of the abutting inclined groove 504 is forced to slide along the tube wall, converting the axial movement tendency into radial pressure on the resilient scraper 503, forcing the resilient scraper 503 to shrink towards the inside of the cleaning sleeve 501, cooperating with the cleaning sleeve 501 to clean the dust on the enlarged diameter portion 302, the entire scraping process can be completed during the continuous rotation of the resilient scraper 503 with the cleaning sleeve 501, which means that the resilient scraper 503 does not only make linear scraping in the axial direction, but forms a spiral advancing motion trajectory, and this composite motion can scrape and clean the dust on the outer wall of the heat exchange tube bundle 301 in all directions and without dead angles, which is more thorough.

[0040] In further embodiments of the present application, a plurality of ash discharge holes 505 are annularly distributed on the cleaning sleeve 501, and the ash discharge holes 505 are staggered with the vanes 502. Specifically, when the cleaning sleeve 501 rotates at high speed under the action of the flue gas, the dust scraped off by the elastic scraper 503 inside the cleaning sleeve 501 will be thrown to the inner wall of the cleaning sleeve 501 due to the centrifugal force. Because of the existence of the ash discharge holes 505, the dust gathered on the inner wall will be thrown out of the ash discharge holes 505 under the continuous action of the centrifugal force and discharged into the main flue gas flow. If there are no ash discharge holes 505, the dust removed by the elastic scraper 503 will accumulate in the annular gap between the cleaning sleeve 501 and the outer wall of the heat exchange tube bundle 301. Over time, not only will this hinder the rotation of the annular cleaning spoiler 5, but it may even block the gap. The staggering of the vanes 502 and the ash discharge holes 505 makes the functional division of the outer wall of the cleaning sleeve 501 clear. The vane 502 area is mainly responsible for driving rotation, while the ash discharge hole 505 area is responsible for ash discharge. This helps to form a relatively orderly flow field locally, reduces the vortex that may be caused by the intersection of the holes and the vanes 502, and reduces unnecessary flow resistance.

[0041] In a further embodiment of the present application, the two movable cleaning frames 4 are vertically slidably installed with pull rods 7 on both sides of the inner wall, the pull rods 7 are vertically distributed with a plurality of abutting blocks 701, the movable cleaning frame 4 is provided with a plurality of accommodating grooves 405 on the side wall for abutting cooperation with each abutting block 701, the pull rod 7 is fixedly connected with a plug-in column 702 in the middle, the support frame 6 is horizontally provided with a wave-shaped guide groove 602 on both sides for the plug-in column 702 to insert, specifically, the pull rod 7 can slide in the vertical direction relative to the movable cleaning frame 4 with a small amplitude, the wave-shaped guide groove 602 is a wave shape with continuous wave peaks and wave troughs, when the movable cleaning frame 4 moves in the horizontal direction under the drive of the double-shaft motor 402, the plug-in column 702 fixedly connected in the middle of the pull rod 7 is forced to slide along the wave-shaped guide groove 602 on the fixed support frame 6, since the wave-shaped guide groove 602 is undulating in the horizontal direction, when the plug-in column 702 slides from the wave trough to the wave peak or vice versa, the groove wall will force the plug-in column 702 to move vertically, this horizontal movement is transmitted to the pull rod 7 through the plug-in column 702, so that the pull rod 7 reciprocatingly moves vertically relative to the movable cleaning frame 4, during the vertical micro-motion of the pull rod 7, the abutting blocks 701 thereon will periodically hit the groove wall of the accommodating groove 405 on the side wall of the movable cleaning frame 4, this continuous and high-frequency impact will generate stable high-frequency vibration, which is transmitted to all the annular cleaning turbulence elements 5 through the movable cleaning frame 4, and finally acts on the elastic scraper 503, which makes the elastic scraper 503 perform rotary scraping while adding a high-frequency micro-vibration or shaking, this rotary scraping plus high-frequency vibration compound soot removal method can effectively break and shake off the hard ash crust, greatly reducing the adhesion between the accumulated dust and the pipe wall, so that the elastic scraper 503 can easily scrape it off, this mechanism is particularly suitable for handling viscous dust generated by fuel oil boilers, biomass boilers, etc., this shaking function is completely derived from the main movement of the movable cleaning frame 4, without the need for an additional power source or control system, realizing efficient use of energy and simplification of the mechanism, the frequency of vibration is proportional to the moving speed of the movable cleaning frame 4, the faster the speed, the higher the shaking frequency, the user can optimize the soot removal effect by adjusting the motor speed, this shaking mechanism does not hinder all the previous functions, the annular cleaning turbulence element 5 still freely rotates under the push of the flue gas, and the dust discharge hole 505 continues to discharge dust by centrifugal force, the horizontal shaking does not affect these functions, but instead forms a multi-dimensional soot removal force through the superposition of rotary scraping, which can also quickly shake off the dust adhered to the heat exchange pipe group 3 and the annular cleaning turbulence element 5 itself.

[0042] In a further embodiment of the present application, the support frame 6 is fixedly connected with a guide plate 603 on one side in the reversing air chamber 205, and the impeller 8 and the spoiler 9 are rotatably installed below the guide plate 603 inside the reversing air chamber 205. The eccentric shaft 801 is installed at both ends of the impeller 8, and the connecting rod 901 is installed at both ends of the spoiler 9 and is hingedly connected with the eccentric shaft 801. Specifically, after the air flowing out from the lower heat exchange tube group 3 enters the reversing air chamber 205, it first impacts on the guide plate 603. The guide plate 603 provides a smooth transition curved surface, which can effectively guide the air flow to smoothly change direction and flow to the inlet of the lower heat exchange tube group 3, thereby avoiding the air directly impacting on the flat chamber wall to generate intense vortex and large local pressure loss, achieving preliminary optimization of the air flow direction, reducing the energy consumption of the fan, and the air flowing through the guide plate 603 has a certain kinetic energy. This part of the air flow impacts and drives the impeller 8 to rotate. The rotating energy of the impeller 8 is completely from the recycled air kinetic energy, without the need for an additional power source, thereby achieving energy saving. When the impeller 8 rotates, the eccentric shaft 801 at both ends thereof makes a circular motion. Through the connection of the connecting rod 901, the circular motion of the eccentric shaft 801 is converted into the reciprocating swing motion of the spoiler 9. The swing amplitude and frequency of the spoiler 9 are determined by the rotating speed of the impeller 8. The internal space of the reversing air chamber 205 is large, and a stable and large-scale backflow vortex area is easily formed. These vortexes not only increase the pressure loss, but also can cause air retention and uneven mixing. The traditional fixed guide vane has limited effect, while the periodic reciprocating swing of the spoiler 9 in this embodiment can actively and continuously break these large-scale vortexes, cut them into small-scale turbulent flows that are easy to dissipate, make the air mixing more uniform and flowing more smoothly, thereby further reducing the flow resistance. After being disturbed by the impeller 8 and the spoiler 9, the turbulence degree of the air is significantly increased. This air with higher turbulence degree after being fully disturbed enters the tubes of the lower heat exchange tube group 3, which can more effectively destroy the air boundary layer in the tubes, thereby strengthening the heat exchange effect on the inner side of the tubes of the upper heat exchange tube group 3. This makes the effect of the two-stage preheating more significant. When the load is high, the air flow is large, the rotating speed of the impeller 8 is fast, the spoiler 9 swings violently, and the disturbance effect is strong. When the load is low, the action is gentle. This self-adaptability ensures that appropriate guide and disturbance effects can be obtained under various working conditions.

[0043] In a further embodiment of the present application, the air preheater 2 is provided with a hopper 10 at the bottom, and a dust filter screen 11 is installed at the top of the hopper 10, and a dust removal groove 12 is formed on both sides of the dust filter screen 11, wherein the bottom of one of the movable cleaning frames 4 abuts against the dust filter screen 11, and the sidewall of the movable cleaning frame 4 is embedded with a dust removal brush 406, specifically, flue gas comes from the boiler, enters the bottom of the air preheater 2 tangentially through the flue gas inlet 201 located on the side of the hopper 10 area, and all the flue gas entering from the flue gas inlet 201 must first pass through the dust filter screen 11 from bottom to top before reaching the heat exchange tube group 3, and the dust filter screen 11 will intercept most of the large particles of dust carried in the flue gas, and the dust concentration of the flue gas entering the heat exchange tube group 3 after pretreatment is significantly reduced, thereby fundamentally reducing the main dust removal load of the annular cleaning spoiler 5 on the heat exchange tube bundle 301, greatly extending the maintenance cycle and service life of the annular cleaning spoiler 5, the movable cleaning frame 4 and the dust removal brush 406 thereon are located above the filter screen, when the movable cleaning frame 4 moves, the dust removal brush 406 will brush the upper surface of the filter screen, and the dust blocked in the mesh can be poked out downward, at the same time, the dust removal brush 406 avoids pushing the large particles of dust to the clean side, and the high-frequency vibration generated by the movable cleaning frame 4 is also transmitted to the dust filter screen 11, forming a strong vibration effect, which can effectively shake off the dust lumps adhered to the lower surface of the filter screen.

[0044] In a further embodiment of the present application, a heat-conducting wire 306 is embedded between the spiral guide vane 304 and the heat exchange tube bundle 301, after the heat-conducting wire 306 is embedded, heat is efficiently transmitted to the spiral guide vane 304, so that the temperature of the spiral guide vane 304 is significantly increased, thereby converting the spiral guide vane 304 from a simple guide component to an efficient extended heat exchange fin, at this time, the spiral guide vane 304 not only guides the rotation of air, but also directly and actively participates in heat exchange with cold air, greatly increasing the effective heat transfer area.

[0045] The above only describes certain exemplary embodiments of the present application by way of illustration, and it is needless to say that those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present application. Therefore, the above drawings and descriptions are illustrative in nature and should not be understood as limiting the scope of protection of the claims of the present application.

Claims

1. An energy-saving boiler, comprising a boiler body (1) and a flue gas duct (101) installed on the boiler body (1), characterized in that, Also includes: An air preheater (2) is installed at the end of the flue gas duct (101). The air preheater (2) is equipped with a pair of heat exchange tube groups (3) distributed along the flue gas emission direction. The heat exchange tube group (3) is composed of multiple heat exchange tube bundles (301). The heat exchange tube bundles (301) are provided with an expansion section (302) and a contraction section (303) that are alternately distributed along their axis. The inner wall of the contraction section (303) is provided with a spiral guide vane (304). A movable cleaning frame (4) with openings at the top and bottom is movably installed in the heat exchange tube bundle (3) and has through holes (401) for the heat exchange tube bundle (301) to pass through. Inside the movable cleaning frame (4), there is an annular cleaning baffle (5) corresponding to each heat exchange tube bundle (301). The annular cleaning baffle (5) contacts the outer wall of the expansion section (302) and the reduction section (303) respectively. The heat exchange tube bundle (3) is fixedly connected to tube sheets (305) on both sides. The heat exchange tube bundle (301) is fixed to two tube sheets (305) at both ends. The air preheater (2) is fixedly connected to a support frame (6). The tube sheet (305) is connected to the support frame (6). The inner walls of the two movable cleaning frames (4) are vertically slidably equipped with pull rods (7). Several abutments (701) are vertically distributed on the pull rods (7). Several receiving grooves (405) that abut against each abutment (701) are opened on the side wall of the movable cleaning frame (4). A plug-in post (702) is fixedly connected to the middle of the pull rod (7). The support frame (6) is horizontally opened with wavy guide grooves (602) for the plug-in post (702) to be inserted. The annular cleaning baffle (5) includes a cleaning sleeve (501) rotatably connected to both sides of the inner wall of the movable cleaning frame (4). Several blades (502) are distributed in annular shape on the outer wall of the cleaning sleeve (501). An elastic scraper (503) is movably inserted into the inner wall of the cleaning sleeve (501). Both sides of the elastic scraper (503) are provided with abutting grooves (504) that abut against the reduced diameter part (303). When the moving cleaning frame (4) moves, the annular cleaning baffle (5) alternately scrapes the outer walls of the expanded diameter section (302) and the narrowed diameter section (303), and rotates under the push of the flue gas to play a baffle role.

2. The energy-saving boiler according to claim 1, characterized in that, The air preheater (2) has a flue gas inlet (201) at the bottom of one side connected to the flue gas duct (101), a flue gas outlet (202) at the top of the air preheater (2), a pair of heat exchange tube groups (3) distributed vertically inside the air preheater (2), and an air inlet (203) and an air outlet (204) connected to the two heat exchange tube groups (3) respectively on the other side of the air preheater (2). The air preheater (2) has a reversing air chamber (205) for connecting the two heat exchange tube groups (3).

3. An energy-saving boiler according to claim 1, characterized in that, A dual-axis motor (402) is fixedly connected between the two movable cleaning frames (4). A transmission rod (403) is installed at both ends of the dual-axis motor (402). A drive gear (404) is fixedly connected to the end of the transmission rod (403). A rack (601) that meshes with the bottom of the drive gear (404) is fixedly connected to both sides of the inner wall of the support frame (6).

4. An energy-saving boiler according to claim 1, characterized in that, The cleaning sleeve (501) has a number of ash discharge holes (505) distributed in a ring, and the ash discharge holes (505) are staggered from the blades (502).

5. An energy-saving boiler according to claim 2, characterized in that, A guide plate (603) is fixedly connected to one side of the support frame (6) inside the reversing chamber (205). An impeller (8) and a baffle plate (9) are rotatably installed inside the reversing chamber (205) below the guide plate (603). An eccentric shaft (801) is installed at both ends of the impeller (8), and a connecting rod (901) is hinged to the eccentric shaft (801) at both ends of the baffle plate (9).

6. An energy-saving boiler according to claim 1, characterized in that, The air preheater (2) is provided with a dust hopper (10) at the bottom, and a dust filter screen (11) is installed on the top of the dust hopper (10). Dust discharge troughs (12) are provided on both sides of the dust filter screen (11). The bottom of one of the movable cleaning frames (4) abuts against the dust filter screen (11), and a dust removal brush (406) is embedded in the side wall of the movable cleaning frame (4).

7. An energy-saving boiler according to claim 1, characterized in that, A heat-conducting metal wire (306) is embedded between the spiral guide vane (304) and the heat exchange tube bundle (301).

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