Low-temperature economizer based on plate heat exchanger

Abstract

The application relates to the technical field of positioning devices, and discloses a low-temperature economizer based on a plate heat exchanger, which comprises an outer shell, a flue gas guide mechanism, a plate heat exchange economizer mechanism, a horizontal ash removal mechanism, a pressure driving mechanism and a reset mechanism. The outer shell is a vertically-placed rectangular box structure, the upper end opening of the outer shell is a flue gas inlet, the lower end opening of the outer shell is a flue gas outlet, and a water outlet collecting box is fixedly connected to the upper part of one side of the outer shell. The application can utilize water inlet pressure as a power source without additionally adding power components, has a simpler and more reliable structure, has a lower operation cost, can make flue gas flow into each flue gas passage more uniformly, avoids the problems of excessively high or low local flow rates, can guarantee the adhesion of a scraper and a heat exchange plate surface to ensure ash removal effect, avoids the scratching of a wear-resistant coating on the heat exchange plate surface by rigid force, and prolongs the service life of the equipment.

Description

Technical Field

[0001] This invention relates to the field of low-temperature economizer technology, specifically a low-temperature economizer based on a plate heat exchanger. Background Technology

[0002] In coal-fired power plant boiler systems, flue gas heat loss accounts for the largest proportion of all heat losses, typically exceeding 50% of the total boiler heat loss. In my country, the flue gas temperature of power plant boilers is generally between 120℃ and 160℃, with some units even higher. If this low-temperature flue gas waste heat is not recovered and utilized but directly discharged into the atmosphere, the high-temperature flue gas carries a large amount of unused heat energy, leading to reduced boiler thermal efficiency and increased standard coal consumption. Therefore, installing a low-temperature economizer in the boiler tail flue to recover flue gas waste heat for heating condensate or other process water has become a standard configuration for energy conservation and emission reduction in coal-fired power plants.

[0003] Currently, the mainstream low-temperature economizers at home and abroad are mainly of three types: tubular, fluoroplastic tubular, and plate. Among them, the plate-type low-temperature economizer, with its straight-channel design, is superior to the tubular structure in terms of anti-clogging and self-cleaning capabilities. However, existing plate-type low-temperature economizers still have the following main defects: First, mechanical cleaning schemes generally use motor-driven lead screws to drive cleaning plates or scrapers to slide along the surface of heat exchange plates to remove dust. The dense transmission components are in a high-temperature, dusty flue gas environment for a long time, which makes them prone to jamming, corrosion, or even burnout failure. Second, uneven flow field distribution after flue gas enters the heat exchange core is a common problem. In some areas, the flue gas velocity is too high, resulting in insufficient heat exchange and increased wear; in other areas, the flow velocity is too low, increasing the risk of ash accumulation. This reduces the effective heat exchange area utilization rate and affects the overall thermal performance of the equipment. Summary of the Invention

[0004] (a) Technical problems to be solved To address the shortcomings of existing technologies, this invention provides a low-temperature economizer based on a plate heat exchanger. The main purpose is to solve the problems that the mechanical cleaning schemes commonly use motor-driven lead screws, which are prone to jamming, corrosion, or even burnout in high-temperature dusty flue gas environments. Furthermore, the flue gas enters the heat exchange core and the flow field distribution is uneven, affecting the overall thermal performance of the equipment.

[0005] (II) Technical Solution To achieve the above objectives, the present invention provides the following technical solution: A low-temperature economizer based on a plate heat exchanger, comprising: The outer casing, flue gas guiding mechanism, plate heat exchanger coal-saving mechanism, horizontal ash removal mechanism, pressure drive mechanism, and reset mechanism are all included. The outer shell is a vertically placed rectangular box structure. The upper opening of the outer shell is a smoke inlet, and the lower opening of the outer shell is a smoke outlet. A water collection box is fixedly connected to the upper part of one side of the outer shell, and a hot water outlet pipe is fixedly connected to one side of the water collection box. A water inlet collection box is fixedly connected to the lower part of one side of the outer shell, and a cold source inlet pipe is fixedly connected to one side of the water inlet collection box. The flue gas guiding mechanism is located inside the flue gas inlet of the outer casing and can guide the flue gas. The plate heat exchanger coal-saving mechanism is located inside the outer shell directly below the flue gas guiding mechanism and can absorb heat from the flue gas. The horizontal dust removal mechanism is located inside the outer casing and can clean the dust on the surface of the heat exchange plate; The pressure driving mechanism includes a cylinder, which is fixedly connected to the middle of the outer side of the outer shell. A first diaphragm is provided inside the cylinder, which divides the cylinder into a pressure-tapping chamber and an atmospheric chamber. A pressure-tapping conduit is connected to one side of the cylinder via a flange. A pressure-tapping pipe is fixedly connected to one side of the water inlet collection tank. The pressure-tapping chamber is connected to the pressure-tapping pipe via the pressure-tapping conduit. A connecting rod is connected to one side of the first diaphragm, and a second diaphragm is connected to one end of the connecting rod. The atmospheric chamber is located between the first and second diaphragms. A vent is provided on the outer side of the cylinder, and the vent communicates with the atmospheric chamber. A push rod is connected to one side of the second diaphragm, and one end of the push rod passes through the outer shell and is connected to the horizontal dust removal mechanism. A packing seal is provided where the push rod passes through the side wall of the shell. The reset mechanism is located inside the cylinder and is used to drive the push rod to retract when the water pressure drops.

[0006] Furthermore, the flue gas guiding mechanism includes a conical guide box, which is fixedly connected to the flue gas inlet at one end of the outer shell. Multiple arc-shaped guide plates are fixedly connected to the inlet end of the conical guide box, and the curvature of the multiple arc-shaped guide plates is directed toward the center line of the conical guide box. Multiple distribution baffles, which are spaced apart along the width direction of the outer shell, are fixedly connected between the inner walls of both sides of the outer shell, and a downward flow channel is formed between every two distribution baffles.

[0007] Based on the aforementioned scheme, the plate heat exchanger coal-saving mechanism includes multiple plate heat exchange cores, which are fixedly connected between the inner walls of both sides of the outer shell. A flue gas channel corresponding to the downstream channel is formed between every two plate heat exchange cores. The outlets of the multiple plate heat exchange cores are all fixedly connected to outlet branch pipes, and the outlet branch pipes are connected to the outlet water collection box. The inlets of the multiple plate heat exchange cores are all fixedly connected to inlet branch pipes, and the inlet branch pipes are connected to the inlet water collection box.

[0008] As a further embodiment of the present invention, the horizontal dust removal mechanism includes an active push plate, which is fixedly connected to one end of a push rod, and the bottom of the active push plate extends to the bottom of the plate heat exchange core. A mounting beam is fixedly connected to the bottom of the active push plate, and the width of the mounting beam is the same as the inner diameter of the outer shell. Multiple mounting longitudinal beams are fixedly connected to one side of the mounting beam, and the multiple mounting longitudinal beams are respectively located at the bottom of multiple plate heat exchange cores. Two guide rods are fixedly connected between the inner walls of both sides of the outer shell, and one end of the guide rod passes through the active push plate. A scraping component is provided on one side of the multiple mounting longitudinal beams.

[0009] Furthermore, the scraping assembly includes multiple L-shaped fixing brackets, which are respectively fixedly connected to both sides of multiple mounting longitudinal beams. Each of the multiple L-shaped fixing brackets has multiple dovetail grooves on one side, and dovetail blocks are slidably connected inside each of the multiple dovetail grooves. Each of the multiple dovetail blocks has a scraper fixedly connected to one side, and a baffle is fixedly connected to one side of each of the multiple scrapers. Each of the multiple dovetail blocks has two first rubber pillars fixedly connected to one side, and one end of each first rubber pillar is connected to the inner wall of the dovetail groove.

[0010] Based on the aforementioned scheme, the reset mechanism includes a reset push plate, which is fixedly connected to the outside of the push rod. A plurality of second rubber pillars are fixedly connected to one side of the reset push plate, and one end of each second rubber pillar is fixed to the outer shell.

[0011] As a further embodiment of the present invention, each of the plurality of plate heat exchange cores is composed of two plate heat exchange plates, and a water flow channel is formed between the two plate heat exchange plates. The surfaces of the plurality of plate heat exchange plates are provided with bulging corrugations and baffle corrugations.

[0012] Furthermore, the scraper has a trapezoidal cross-section, with the wide bottom side of the trapezoid facing the surface of the plate heat exchange core. The upper scraper forms an acute angle of 70°-85° with the plate heat exchange core, and the lower scraper forms a slightly smaller angle of 60°-80° with the plate heat exchange core.

[0013] Based on the aforementioned scheme, the windward surface of the plate heat exchange core is provided with a wear-resistant coating with a coating thickness of 0.3mm-0.55mm.

[0014] (III) Beneficial Effects Compared with the prior art, the present invention provides a low-temperature economizer based on a plate heat exchanger, which has the following beneficial effects: 1. Using water pressure as power to avoid the failure of electric drive in high-temperature flue gas: This invention, by setting up a pressure drive mechanism, can use the change of inlet water pressure to drive the horizontal dust removal mechanism to move as a whole. There is no need to place the transmission components such as motor screws inside the high-temperature dusty flue gas, avoiding the problem of transmission components getting stuck, corroded or even burned out under harsh working conditions for a long time. At the same time, using inlet water pressure as a power source eliminates the need for additional power components, making the structure simpler, more reliable and lower in operating cost.

[0015] 2. Pre-diversion of flue gas to improve flow field uniformity: By setting up a flue gas guiding mechanism, this invention can pre-divide the flue gas at the flue gas inlet, so that the flue gas can flow into each flue gas channel more evenly, avoiding the problem of excessively high or low local flow velocities. This reduces the wear of heat exchange plates caused by excessively high local flow velocities and also reduces the risk of ash accumulation caused by excessively low local flow velocities, improving the utilization rate of the effective heat exchange area and improving the overall thermal performance of the equipment.

[0016] 3. Elastic scraping, cleaning dust while protecting the heat exchange plate: The present invention uses a scraping component in the horizontal dust removal mechanism to scrape off the dust attached to the surface of the plate heat exchange core during movement. The first rubber column can buffer the force on the scraper, ensuring that the scraper is in close contact with the surface of the heat exchange plate to ensure the dust removal effect, and also avoiding the rigid force from scratching the wear-resistant coating on the surface of the heat exchange plate, thus improving the service life of the equipment.

[0017] 4. Pure mechanical reset to achieve a complete cleaning cycle: By setting a reset mechanism, the present invention can drive the cleaning mechanism to automatically reset when the water pressure drops, thus completing one cleaning action. In addition, the second rubber column can not only provide reset power, but also buffer the impact force during the reset process, thereby improving the stability of the structure operation. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the front three-dimensional structure of a low-temperature economizer based on a plate heat exchanger proposed in this invention; Figure 2 This is a top-view three-dimensional structural diagram of a low-temperature economizer based on a plate heat exchanger proposed in this invention; Figure 3 This is a cross-sectional view of the conical flow guide box structure of a low-temperature economizer based on a plate heat exchanger proposed in this invention; Figure 4 This is a schematic cross-sectional view of the outer shell structure of a low-temperature economizer based on a plate heat exchanger proposed in this invention. Figure 5 This is an enlarged structural diagram of section A of a low-temperature economizer based on a plate heat exchanger proposed in this invention; Figure 6This is a partially enlarged schematic diagram of the horizontal ash removal mechanism of a low-temperature economizer based on a plate heat exchanger proposed in this invention. Figure 7 This is a cross-sectional view of the scraping component of a low-temperature economizer based on a plate heat exchanger proposed in this invention. Figure 8 This is a schematic cross-sectional view of the plate heat exchanger core structure of a low-temperature economizer based on a plate heat exchanger proposed in this invention. In the diagram: 1. Outer shell; 101. Smoke inlet; 102. Smoke outlet; 2. Water collection tank; 201. Water outlet branch pipe; 202. Hot water outlet pipe; 3. Cylinder; 301. Pressure tapping conduit; 302. Pressure tapping pipe; 303. Vent hole; 304. First diaphragm; 305. Pressure tapping chamber; 306. Atmospheric chamber; 307. Connecting rod; 308. Push rod; 309. Second diaphragm; 4. Water collection tank; 401. Water inlet branch pipe; 402. Cold source inlet pipe; 5. Conical guide box; 501. Arc-shaped guide plate; 502. Distribution baffle; 6. Flue gas passage; 7. Plate heat exchanger core; 701. Baffle corrugated; 702. Water flow passage; 703. Bump corrugated; 8. L-shaped fixing bracket; 801. Rubber column; 802. Baffle; 803. Dovetail block; 804. Dovetail groove; 805. Scraper; 9. Active push plate; 901. Mounting longitudinal beam; 902. Mounting crossbeam. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] Reference Figures 1-8 A low-temperature economizer based on a plate heat exchanger, comprising: 1. Outer shell, flue gas guiding mechanism, plate heat exchanger coal saving mechanism, horizontal ash removal mechanism, pressure driving mechanism, and reset mechanism; The outer casing 1 is a vertically placed rectangular box structure. The upper opening of the outer casing 1 is the flue gas inlet 101, which is used to connect with the tail flue of the boiler. The lower opening of the outer casing 1 is the flue gas outlet 102, which is used to connect with the dust collector or desulfurization system. A water collection box 2 is fixed to the upper part of one side of the outer casing 1 by bolts. A hot water outlet pipe 202 is welded to one side of the water collection box 2 to send the heated condensate back to the condensate system. A water inlet collection box 4 is fixed to the lower part of one side of the outer casing 1 by bolts. A cold source inlet pipe 402 is welded to one side of the water inlet collection box 4 to introduce low temperature feedwater into the power plant condensate system. The flue gas guiding mechanism is installed inside the flue gas inlet 101 of the outer shell 1 to pre-distribute and rectify the incoming flue gas. The flue gas guiding mechanism includes a conical guiding box 5, which is a frustum-shaped box with a larger upper end and a smaller lower end. Its upper opening is fixed to the flue gas inlet 101 of the outer shell 1 by bolts, and its lower opening is suspended above the plate heat exchanger coal saving mechanism. The conical guide box 5 is fixed to the smoke inlet 101 at one end of the outer shell 1 by bolts. Multiple arc-shaped guide plates 501 are welded to the inlet end of the conical guide box 5. The curves of the multiple arc-shaped guide plates 501 are directed toward the center line of the conical guide box 5, which is used to guide the flue gas from the surrounding area to the center and eliminate the eddies generated by the sudden expansion of the smoke inlet. Multiple distribution baffles 502, arranged at intervals along the width direction of the outer shell 1, are fixed between the inner walls on both sides of the outer shell 1 by bolts. A downward flow channel is formed between every two distribution baffles 502 to uniformly divide the flue gas into multiple independent airflows along the width direction of the shell 1. The plate heat exchanger is located inside the outer shell 1, directly below the flue gas guiding mechanism. It can absorb heat from the flue gas. The plate heat exchanger includes multiple plate heat exchange cores 7, which are fixed to the inner walls of both sides of the outer shell 1 by bolts. A flue gas channel 6 is formed between every two plate heat exchange cores 7, corresponding to the downflow channel. Each flue gas channel 6 is aligned vertically with each feeding channel of the upper flue gas guiding mechanism, so that each pre-distributed flue gas enters the corresponding flue gas channel 6 independently, avoiding lateral diffusion of the flue gas in the heat exchange area. The outlets of multiple plate heat exchange cores 7 are all welded with water outlet branch pipes 201, and the water outlet branch pipes 201 are connected to the water outlet collection box 2. The inlets of multiple plate heat exchange cores 7 are all welded with water inlet branch pipes 401, and the water inlet branch pipes 401 are connected to the water inlet collection box 4. The spacing between each plate heat exchanger core 7 is designed to be 20-30mm, i.e., a wide flow channel design, which is much larger than the conventional narrow flow channel of less than 10mm. This avoids dust bridging and clogging. The flue gas velocity is designed to be 8-10m / s. While maintaining sufficient turbulence, the erosion and wear rate of dust on the plate surface is reduced. The wear rate is proportional to the cube of the gas velocity. By reducing the flue gas velocity from 10-12m / s in the tubular type to 8-10m / s, the wear rate can be reduced to about 30% of the original. The pressure drive mechanism includes a cylinder 3, which is bolted to the outer middle of the outer shell 1. A first diaphragm 304 is installed inside the cylinder 3, dividing the interior of the cylinder 3 into a pressure-tapping chamber 305 and an atmospheric chamber 306. A pressure-tapping conduit 301 is connected to one side of the cylinder 3 via a flange, and a pressure-tapping pipe 302 is welded to one side of the inlet water collection tank 4. The pressure-tapping chamber 305 is connected to the pressure-tapping pipe 302 via the pressure-tapping conduit 301, and is used to sense changes in the water pressure of the condensate system. A connecting rod 307 is connected to one side of the first diaphragm 304, and a second diaphragm 309 is connected to one end of the connecting rod 307. An atmospheric chamber 306 is located between the first diaphragm 304 and the second diaphragm 309. A vent 303 is provided on the outer side of the cylinder 3, and the vent 303 is connected to the atmospheric chamber 306, so that the back pressure side of the diaphragm is always at atmospheric pressure. A push rod 308 is connected to one side of the second diaphragm 309. One end of the push rod 308 passes through the outer shell 1 and is connected to the horizontal dust removal mechanism. A packing seal is provided where the push rod 308 passes through the side wall of the shell 1. The packing seal is filled with flexible graphite or polytetrafluoroethylene braided packing and is pressed with a pressure cap to ensure that the flue gas does not leak out. The reset mechanism is located inside the cylinder 3 and is used to drive the push rod 308 to retract when the water pressure drops. The reset mechanism includes a reset push plate 11, which is a disc-shaped plate located inside the cylinder 3 and moves together with the push rod 308. The reset push plate 11 is fixed to the outside of the push rod 308 by bolts. A plurality of second rubber pillars 10 are bonded to one side of the reset push plate 11, and one end of the second rubber pillars 10 is fixed to the outer shell 1. The second rubber pillars 10 are made of heat-resistant fluororubber. The horizontal dust removal mechanism is installed inside the outer casing 1 and can clean the dust on the surface of the heat exchange plate. The horizontal dust removal mechanism includes an active push plate 9, which is fixed to one end of the push rod 308 by bolts, so that the active push plate 9 can move synchronously with the horizontal reciprocating motion of the push rod 308. The bottom of the active push plate 9 extends to the bottom of the plate heat exchange core 7. A mounting beam 902 is welded to the bottom of the active push plate 9. The width of the mounting beam 902 is the same as the inner diameter of the outer shell 1. Multiple mounting longitudinal beams 901 are welded to one side of the mounting beam 902. The multiple mounting longitudinal beams 901 are located at the bottom of multiple plate heat exchange cores 7. The length of the multiple mounting longitudinal beams 901 is the length of the flue minus the stroke length of the push rod 308. The number of mounting longitudinal beams 901 is the same as the number of flue gas passages 6. Two guide rods 903 are welded between the inner walls of the two sides of the outer shell 1, and one end of the guide rod 903 passes through the active push plate 9. The active push plate 9 has a guide rod 903 passing through the corresponding guide hole, which provides guidance and support for the horizontal reciprocating motion of the active push plate 9. A scraping assembly is provided on one side of multiple mounting longitudinal beams 901. The scraping assembly includes multiple L-shaped fixing brackets 8. The multiple L-shaped fixing brackets 8 are respectively fixed to both sides of multiple mounting longitudinal beams 901 by bolts. The spacing between the L-shaped fixing brackets 8 located on the same side of the mounting longitudinal beam 901 is equal to the stroke length of the push rod 308. Multiple L-shaped fixing brackets 8 are provided with multiple dovetail grooves 804 on one side, and dovetail blocks 803 are slidably connected inside the multiple dovetail grooves 804. A scraper 805 is fixed to one side of the multiple dovetail blocks 803 by bolts. The scraper 805 is made of polytetrafluoroethylene or filled reinforced polytetrafluoroethylene, and has the characteristics of temperature resistance, wear resistance and self-lubrication. Each of the multiple scrapers 805 has a baffle 802 welded to one side. The length and width of the baffle 802 are greater than the width and length of the dovetail groove 804, which can block the groove opening and prevent foreign objects from entering the dovetail groove 804. Two first rubber pillars 801 are bonded to one side of each of the multiple dovetail blocks 803, and one end of the first rubber pillar 801 is connected to the inner wall of the dovetail groove 804. The first rubber pillar 801 is also made of heat-resistant fluororubber. Each of the multiple plate heat exchange cores 7 is composed of two plate heat exchange plates, and a water flow channel 702 is formed between the two plate heat exchange plates. The surfaces of the multiple plate heat exchange plates are provided with bulging corrugations 703 and baffle corrugations 701. Each plate heat exchange core 7 is made of two plate heat exchange plates by fully automatic laser oxidation-free welding. The plate heat exchange plates are made of 316L stainless steel plates and are formed by hydraulic expansion. The plate thickness is 0.8mm-1.7mm and the pressure bearing capacity is 4MPa-6.4MPa, which can meet the high pressure operation requirements of the power plant condensate system.

[0021] The scraper 805 has a trapezoidal cross section, with the wide bottom side of the trapezoid facing the surface of the plate heat exchange core 7. The upper scraper 805 forms an acute angle of 70°-85° with the plate heat exchange core 7, and the lower scraper 805 forms a slightly smaller angle of 60°-80° with the plate heat exchange core 7. In actual operation, in the 0%-60% height area of ​​the plate, due to the higher flue gas temperature and wall temperature above the water dew point, the accumulated ash is mainly dry and loose fly ash. However, in the 60%-100% height area, where the flue gas has cooled significantly and the wall temperature is below the water dew point, water vapor in the flue gas forms a condensate film on the plate surface, resulting in ash containing 12%-18% moisture, appearing as a wet, viscous mud. Therefore, the upper scraper uses a large angle of 70°-85° to enhance the scraping and peeling effect on dry ash, while the lower scraper uses a slightly smaller angle of 60°-80° to increase the lateral pushing force on the wet mud, effectively preventing the accumulation of wet mud from causing blockage and collapse. The windward side of the plate heat exchange core 7 is provided with a wear-resistant coating with a thickness of 0.3mm-0.55mm. The wear-resistant coating is an alloy ceramic coating sprayed by supersonic plasma. The alloy ceramic coating is made of nickel-chromium chromium carbide and has a surface hardness of HRC55° or higher.

[0022] Working principle: The high-temperature flue gas (120℃-180℃) discharged from the tail end of the boiler enters through the flue gas inlet 101 at the upper end of the outer shell 1. The flue gas first enters the conical guide box 5. Under the combined action of the guide slope of the inner wall of the conical guide box 5 and the arc-shaped guide plate 501, the flue gas velocity tends to be uniform. Subsequently, the flue gas enters several downstream channels formed by multiple distribution baffles 502. Each downstream channel corresponds one-to-one with the flue gas channel 6 below, and the flue gas is evenly distributed into each flue gas channel 6 along the width direction.

[0023] The uniformly distributed flue gas flows from top to bottom through the flue gas channels 6 between the plate heat exchange cores 7. At the same time, low-temperature feedwater (approximately 40℃-70℃) from the power plant condensate system enters the water collection tank 4 through the cold source inlet 402 and is distributed through the branch pipes into the water flow channels 702 inside each plate heat exchange core 7. The water flows in a tortuous flow path formed by the baffle corrugations 701 in the water flow channels 702, increasing the flow length and heat exchange time. The flue gas flows from top to bottom through the wave-shaped channels formed by the bulging corrugations 703 in the flue gas channels 6. The presence of the bulging corrugations 703 causes the cross-sectional shape of the flow channel to change continuously along the flow direction, forming turbulence at a relatively low Reynolds number, which greatly enhances the fluid disturbance and improves the convective heat transfer coefficient. The heat from the flue gas is transferred to the water flow through the metal wall of the plate heat exchange core 7, and the flue gas temperature decreases (to about 90℃-110℃). After the water temperature rises, it is collected in the outlet water collection box 2 and discharged from the cold source outlet 202 back to the condensate system.

[0024] In actual operation, the water pressure of the power plant condensate system has inherent pulsations due to factors such as pump start-up and shutdown and valve adjustment. When the cold source inlet water pressure increases, the water pressure in the inlet collection tank 4 increases synchronously. The pressure is transmitted to the pressure tapping chamber 305 of the pressure drive mechanism through the pressure tapping pipe 302 and pressure tapping conduit 301, pushing the first diaphragm 304 to bulge towards the atmospheric chamber 306, which drives the connecting rod 307, push rod 308 and the second diaphragm 309 to move synchronously. When the push rod 308 extends horizontally under the drive of the diaphragm, the reset push plate 11 moves with the push rod 308 and compresses the second rubber column 10. The second rubber column 10 stores elastic potential energy and simultaneously pushes the active push plate 9 of the horizontal dust removal mechanism to move along the guide rod. The active push plate 9 drives the mounting longitudinal beam 901 and the mounting cross beam 902 to move horizontally synchronously. The scraper 805 on the mounting longitudinal beam 901 moves along the surface of the plate heat exchange core 7 and scrapes off the ash attached to the surface of the heat exchange core. During this process, when the scraper 805 is subjected to resistance and compression from the uneven structure on the surface of the heat exchange plate, under the pre-compression elastic force of the first rubber column 801, the dovetail block 803 is continuously pushed towards the plate heat exchange core 7, so that the front end of the scraper 805 is always elastically pressed against the surface of the plate heat exchange core 7 with a certain adhesion force. When the scraper 805 encounters the raised peak of the bulge 703, the scraper 805 is pushed back, and the first rubber column 801 is further compressed to absorb the impact. When the scraper 805 crosses the peak and reaches the trough, the first rubber column 801 releases its elastic force to push the scraper 805 out, so that it fits tightly against the plate surface at the trough, which keeps the scraper always in contact with the surface of the heat exchange plate and avoids rigid scraping damage to the wear-resistant coating on the surface of the heat exchange plate.

[0025] When the inlet water pressure drops, the pressure in the pressure tapping chamber 305 decreases synchronously. When the water pressure in the inlet water collection tank 4 drops and the diaphragm recovers its deformation, the second rubber column 10 releases its stored elastic potential energy, pushing the reset push plate 11 and push rod 308 to retract horizontally, thereby driving the entire horizontal dust removal mechanism to complete one reset stroke. The second rubber column 10 has high damping characteristics when releasing elastic force, which can effectively absorb the impact energy during the reset process, suppress high-frequency flutter, and make the operation of the dust removal mechanism more stable, driving the entire horizontal dust removal mechanism back to the initial position, completing one complete dust removal cycle, and waiting for the next pressure trigger.

[0026] The entire ash removal process requires no additional power. All transmission components are located outside the high-temperature flue gas chamber, ensuring a stable and reliable structure. This not only guarantees the online ash removal effect but also extends the overall service life of the equipment and improves the heat exchange stability of the plate-type low-temperature economizer.

[0027] All electrical components mentioned in this article are connected to an external main controller and 220V AC mains power, and the main controller can be a conventional known device such as a computer that provides control.

[0028] In the description herein, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to fixed connections, mechanical connections, electrical connections, or direct connections. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances.

[0029] In the description herein, it should be noted that the terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0030] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A low-temperature economizer based on a plate heat exchanger, characterized in that, include: The enclosure (1) comprises a flue gas guiding mechanism, a plate heat exchanger coal-saving mechanism, a horizontal ash removal mechanism, a pressure driving mechanism, and a reset mechanism. The enclosure (1) is a vertically placed rectangular box structure. The upper opening of the enclosure (1) is a flue gas inlet (101), and the lower opening of the enclosure (1) is a flue gas outlet (102). A water collection box (2) is fixedly connected to the upper part of one side of the enclosure (1), and a hot water outlet pipe (202) is fixedly connected to one side of the water collection box (2). A water inlet is fixedly connected to the lower part of one side of the enclosure (1). The collection box (4) has a cold source inlet pipe (402) fixedly connected to one side; the flue gas guiding mechanism is set inside the flue gas inlet (101) of the outer shell (1); the plate heat exchange coal saving mechanism is set inside the outer shell (1) directly below the flue gas guiding mechanism; the horizontal dust removal mechanism is set inside the outer shell (1) and can clean the dust on the surface of the heat exchange plate; the pressure driving mechanism includes a cylinder (3), the cylinder (3) is fixedly connected to the middle of the outer side of the outer shell (1), and a first diaphragm (3) is provided inside the cylinder (3). 04), the cylinder (3) is divided into a pressure-tapping chamber (305) and an atmospheric chamber (306) by a first diaphragm (304). A pressure-tapping conduit (301) is connected to one side of the cylinder (3) via a flange. A pressure-tapping pipe (302) is fixedly connected to one side of the water inlet collection tank (4). The pressure-tapping chamber (305) is connected to the pressure-tapping pipe (302) via the pressure-tapping conduit (301). A connecting rod (307) is connected to one side of the first diaphragm (304), and a second diaphragm (309) is connected to one end of the connecting rod (307). The atmospheric chamber (306) is located between the first diaphragm (304) and the second diaphragm (309). The outer side of the cylinder (3) is provided with a vent hole (303), and the vent hole (303) is connected to the atmospheric chamber (306). A push rod (308) is connected to one side of the second diaphragm (309). One end of the push rod (308) passes through the outer shell (1) and is connected to the horizontal dust removal mechanism. The push rod (308) is provided with a packing seal at the side wall of the shell (1). The reset mechanism is located inside the cylinder (3).

2. A low-temperature economizer based on a plate heat exchanger according to claim 1, characterized in that, The flue gas guiding mechanism includes a conical guide box (5), which is fixedly connected to the smoke inlet (101) at one end of the outer shell (1). Multiple arc-shaped guide plates (501) are fixedly connected to the inlet end of the conical guide box (5). The curves of the multiple arc-shaped guide plates (501) are directed toward the center line of the conical guide box (5). Multiple distribution partitions (502) are fixedly connected between the inner walls of the two sides of the outer shell (1) and are spaced apart along the width direction of the outer shell (1). A downward flow channel is formed between every two distribution partitions (502).

3. A low-temperature economizer based on a plate heat exchanger according to claim 1, characterized in that, The plate heat exchanger coal-saving mechanism includes multiple plate heat exchange cores (7), which are fixedly connected between the inner walls of the outer shell (1) on both sides. A flue gas channel (6) is formed between every two plate heat exchange cores (7) and corresponds one-to-one with the downstream channel. The outlet of each of the multiple plate heat exchange cores (7) is fixedly connected to an outlet branch pipe (201), and the outlet branch pipe (201) is connected to the outlet collection box (2). The inlet of each of the multiple plate heat exchange cores (7) is fixedly connected to an inlet branch pipe (401), and the inlet branch pipe (401) is connected to the inlet collection box (4).

4. A low-temperature economizer based on a plate heat exchanger according to claim 3, characterized in that, The horizontal dust removal mechanism includes an active push plate (9), which is fixedly connected to one end of a push rod (308), and the bottom of the active push plate (9) extends to the bottom of the plate heat exchange core (7). The bottom of the active push plate (9) is fixedly connected to an installation beam (902), the width of which is the same as the inner diameter of the outer shell (1). A plurality of installation longitudinal beams (901) are fixedly connected to one side of the installation beam (902), and the plurality of installation longitudinal beams (901) are located at the bottom of the plurality of plate heat exchange cores (7). Two guide rods (903) are fixedly connected between the inner walls of the two sides of the outer shell (1), and one end of the guide rod (903) passes through the active push plate (9). A scraping component is provided on one side of the plurality of installation longitudinal beams (901).

5. A low-temperature economizer based on a plate heat exchanger according to claim 4, characterized in that, The scraping assembly includes multiple L-shaped fixing brackets (8), which are respectively fixedly connected to both sides of multiple mounting longitudinal beams (901). Multiple dovetail grooves (804) are provided on one side of each of the multiple L-shaped fixing brackets (8). Dovetail blocks (803) are slidably connected inside each of the multiple dovetail grooves (804). Scrapers (805) are fixedly connected to one side of each of the multiple dovetail blocks (803). Baffles (802) are fixedly connected to one side of each of the multiple scrapers (805). Two first rubber columns (801) are fixedly connected to one side of each of the multiple dovetail blocks (803), and one end of the first rubber column (801) is connected to the inner wall of the dovetail groove (804).

6. A low-temperature economizer based on a plate heat exchanger according to claim 4, characterized in that, The reset mechanism includes a reset push plate (11), which is fixedly connected to the outside of the push rod (308). A plurality of second rubber columns (10) are fixedly connected to one side of the reset push plate (11), and one end of the second rubber column (10) is fixed to the outer shell (1).

7. A low-temperature economizer based on a plate heat exchanger according to claim 4, characterized in that, Each of the multiple plate heat exchange cores (7) is composed of two plate heat exchange plates, and a water flow channel (702) is formed between the two plate heat exchange plates. The surfaces of the multiple plate heat exchange plates are provided with bulging corrugations (703) and baffle corrugations (701).

8. A low-temperature economizer based on a plate heat exchanger according to claim 5, characterized in that, The scraper (805) has a trapezoidal cross section, with the wide bottom side of the trapezoid facing the surface of the plate heat exchange core (7). The upper scraper (805) forms an acute angle of 70°-85° with the plate heat exchange core (7), and the lower scraper (805) forms a slightly smaller angle of 60°-80° with the plate heat exchange core (7).

9. A low-temperature economizer based on a plate heat exchanger according to claim 1, characterized in that, The windward side of the plate heat exchange core (7) is provided with a wear-resistant coating with a coating thickness of 0.3mm-0.55mm.

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