A thermal power plant flue dust residual heat recovery device and method

Abstract

The application provides a thermal power plant flue dust waste heat recovery device and method, which comprises a shell, a heat storage mechanism, a heat release mechanism and a dust removal mechanism, an insulating lining and a guide plate are arranged in the shell, the heat storage mechanism realizes waste heat storage and stable release through a straight pipe, heat conduction fins and a phase change material layer, the heat release mechanism realizes directional output of waste heat by means of a circulating pump and a plate heat exchanger, and the dust removal mechanism removes dust by translation of a shock generator driven by a motor. The application integrates multiple functions, solves the problems of dust accumulation, unstable heat source and insufficient waste heat recovery of traditional devices, can adapt to boiler load fluctuation, is corrosion-resistant and low-maintenance, can deeply recover waste heat in a medium-low temperature section, significantly improves energy utilization rate, and reduces environmental pollution and operation cost.

Description

Technical Field

[0001] This invention relates to the field of waste heat recovery devices, and in particular to a waste heat recovery device and method for flue gas from thermal power plants. Background Technology

[0002] During the coal-fired power generation process, the high-temperature flue gas discharged from the boiler carries a large amount of waste heat. Direct emission of this waste heat not only causes serious energy waste but also exacerbates thermal pollution and environmental burden. Efficient recovery of flue gas waste heat has become a key path for thermal power plants to reduce coal consumption, improve thermal efficiency, and reduce carbon emissions. The recovered waste heat can be utilized for multiple purposes, resulting in significant economic and environmental benefits.

[0003] Currently, most mainstream flue gas waste heat recovery technologies in the industry use conventional equipment such as finned tube heat exchangers and heat pipe heat exchangers. However, there are many technical bottlenecks in actual operation: First, flue gas contains a large amount of fly ash and acidic gases. The complex finned and tube bundle structure of conventional heat exchangers easily leads to the accumulation of flue gas dust, forming an insulation layer, which causes the heat exchange efficiency to drop sharply over time. Second, if the temperature of the heat exchange wall is lower than the acid dew point of the flue gas, it is easy to cause low-temperature corrosion, leading to equipment perforation and leakage, which seriously affects the service life and operational safety. Third, boiler load fluctuations cause frequent changes in flue gas parameters. The instantaneous direct heat exchange mode of conventional heat exchangers is difficult to adapt to these fluctuations, resulting in unstable heat output and affecting the stable utilization of subsequent processes. Fourth, traditional technologies are limited by materials and safety, and can only recover flue gas temperature to a conservative level. The waste heat in the medium and low temperature range is not deeply explored, and the energy recovery potential is insufficient. Fifth, ash removal requires frequent boiler shutdowns. Steam soot blowing is energy-intensive and easily wears down equipment, while sonic soot blowing has cleaning dead spots in dense spaces.

[0004] In recent years, heat storage and heat exchange technology using phase change materials (PCMs) has gradually emerged. PCMs can absorb and release a large amount of latent heat near their phase change temperature, theoretically enabling stable heat output. However, when this technology is applied to the flue gas environment of thermal power plants, prominent problems remain: PCMs themselves have poor thermal conductivity, resulting in slow heat storage and release rates; PCM units are easily covered by flue gas dust in the flue, hindering their heat absorption from the flue gas; and how to modularly integrate functions such as heat storage, heat release, and dust removal into a compact and reliable device to achieve efficient and maintenance-free operation has become a pressing technical challenge. Summary of the Invention

[0005] The purpose of this invention is to provide a device and method for recovering waste heat from flue gas in thermal power plants. The invention aims to provide a device and method that integrates heat storage, heat release, dust removal and parameter monitoring functions. It uses phase change material heat storage to buffer flue gas parameter fluctuations and translational shock wave dust removal to avoid the impact of ash accumulation, thereby achieving efficient and stable recovery and utilization of waste heat from flue gas in thermal power plants. The device and method are also low-maintenance and corrosion-resistant.

[0006] According to one objective of the present invention, a waste heat recovery device for flue gas in a thermal power plant is provided, comprising a shell, a heat storage mechanism, a heat release mechanism, and a dust removal mechanism; one side of the shell is connected to an inlet pipe and the other side is connected to an outlet pipe, an insulating lining is fixed to the inner wall of the shell, and inclined guide plates are fixed to the front and rear ends of the inner wall of the shell; the heat storage mechanism includes a support frame, a first outer shell and a second outer shell are fixed to the top of the support frame, the inner cavities of the first outer shell and the second outer shell are filled with a phase change material layer, and straight pipes are provided inside the first outer shell and the surface of the straight pipes is fixed with heat-conducting fins, and the first outer shell is connected to a working fluid. The first outer casing is connected to the working fluid discharge pipe, and the two straight pipes are interconnected. The heat release mechanism includes a circulating pump, a plate heat exchanger, and a three-way valve. The circulating pump connects the working fluid discharge pipe to the plate heat exchanger. The plate heat exchanger is connected to the three-way valve through the working fluid circulation pipe. The three-way valve is connected to the working fluid inlet pipe and the buffer tank delivery pipe, respectively. The dust removal mechanism includes a motor, a lead screw, a moving frame, and a shock wave generator. The motor drives the lead screw to rotate. The moving frame is threadedly connected to the lead screw and its bottom is connected to the shock wave generator. The shock wave generator is in contact with the surfaces of the first outer casing and the second outer casing.

[0007] Furthermore, the thermal insulation lining is made of high-temperature resistant rock wool and vacuum insulation board composite, and the phase change material layer is made of inorganic hydrated salt phase change material with a melting point of 80-120℃.

[0008] Furthermore, a connecting seat is fixed on one side of both the first housing and the second housing, and a temperature sensor and a pressure sensor are respectively fixed on the surface of the connecting seat; the working fluid discharge pipe is connected to a water temperature sensor, and the working fluid inlet pipe is connected to an inlet pressure gauge.

[0009] Furthermore, the bottom of the housing is connected to a funnel-shaped dust collection hood, and the bottom of the dust collection hood is connected to a control valve; sliding rods are fixed on both sides of the inner wall of the housing, and the sliding rods are slidably connected to the movable frame.

[0010] Furthermore, the first housing has a first straight tube inside, and the second housing has a second straight tube inside. The first and second straight tubes are arranged in parallel. The heat-conducting fins are evenly distributed along the length of the straight tubes, and the spacing between adjacent heat-conducting fins is 10-20 mm. The gap between the shock wave generator and the surfaces of the first and second housings does not exceed 2 mm.

[0011] Furthermore, the plate heat exchanger has a detachable structure, with a drain pipe connected to the top of the other side of the plate heat exchanger and a water inlet pipe connected to the bottom of the plate heat exchanger; the angle between the guide plate and the axis of the shell is 30-60°.

[0012] Furthermore, the cone angle of the dust collection hood is 60-90°; the circulating working fluid is synthetic heat transfer oil.

[0013] Furthermore, the heat exchange area of ​​the plate heat exchanger is adapted to the heat storage power of the heat storage mechanism; the three-way valve switches the working fluid flow direction according to the system load.

[0014] According to another objective of the present invention, the present invention provides a method for recovering waste heat from flue gas in a thermal power plant, implemented based on the above-mentioned apparatus, comprising the following steps: S1. High-temperature dust-laden flue gas enters the casing through the flue pipe, and the guide plate guides the flue gas to flow evenly through the first and second outer casing areas; S2. The heat from the flue gas is transferred to the phase change material layer through the outer shell wall and heat-conducting fins. The phase change material absorbs heat and undergoes a phase change to store energy, or undergoes a reverse phase change to release latent heat and heat the circulating working fluid. S3. The circulating pump drives the working fluid to circulate between the heat storage mechanism and the plate heat exchanger, and the working fluid exchanges heat with the external medium to realize the utilization of waste heat. S4. The dust removal mechanism operates synchronously. The motor drives the shock wave generator to move along the surface of the outer shell, stripping off the smoke and dust, which is then collected and discharged by the dust collection hood.

[0015] Furthermore, in step S2, the thermal storage status is monitored in real time by temperature and pressure sensors; in step S3, the three-way valve enables the working fluid to form a closed loop circulation when the external heat demand is stable, and introduces part of the working fluid into the buffer facility when the system load fluctuates; in step S4, the smoke and dust are discharged periodically through the control valve without the need to stop the machine for cleaning.

[0016] This invention achieves efficient and stable recovery of waste heat from flue gas through the integrated design of heat storage, heat release, and dust removal mechanisms. The phase change material layer, combined with heat-conducting fins, solves the problem of poor thermal conductivity of phase change materials, buffering boiler load fluctuations and providing a stable heat source. The translational shock wave dust removal mechanism can completely remove flue gas from the outer shell surface, eliminating cleaning dead zones and requiring no boiler shutdown, thus preventing ash accumulation from affecting heat exchange efficiency. The insulating lining reduces heat loss, and the phase change heat storage mode reduces the risk of low-temperature corrosion. The device has a compact structure and synergistic functions, deeply exploiting waste heat in the medium and low temperature range while reducing operation and maintenance costs, making it suitable for the complex operating conditions of thermal power plants. Attached Figure Description

[0017] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0018] Figure 1This is a schematic diagram of the structure of an embodiment of the present invention; Figure 2 This is a schematic diagram of the rear structure of the housing according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the internal structure of the housing according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the dust removal mechanism structure according to an embodiment of the present invention; Figure 5 This is a top view of the first and second outer shells according to an embodiment of the present invention; Figure 6 This is a side view of the first and second outer shells according to an embodiment of the present invention; Figure 7 This is a schematic diagram of the internal structure of the first and second outer shells according to an embodiment of the present invention; Figure 8 This is a bottom view of the housing structure according to an embodiment of the present invention; In the diagram: 1. Shell; 2. Inlet pipe; 3. Exhaust pipe; 4. Insulation lining; 5. Heat storage mechanism; 51. Support frame; 52. First outer shell; 53. Second outer shell; 54. Working fluid inlet pipe; 55. First straight pipe; 56. Second straight pipe; 57. Working fluid outlet pipe; 58. Heat-conducting fins; 59. Phase change material layer; 6. Heat release mechanism; 61. Circulation pump; 62. Base plate; 63. Plate heat exchanger; 64. 65. Working fluid circulation pipe; 66. Three-way valve; 77. Buffer tank conveying pipe; 8. Dust removal mechanism; 9. Motor; 10. Lead screw; 11. Moving frame; 12. Shock generator; 13. Connecting seat; 14. Temperature sensor; 15. Pressure sensor; 16. Water temperature sensor; 17. Inlet pressure gauge; 18. Dust collection hood; 19. Control valve; 10. Drain pipe; 10. Water inlet pipe; 11. Slide bar; 12. Guide plate. Detailed Implementation

[0019] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. 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] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0021] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified. Furthermore, the terms "installed," "connected," and "linked" should be interpreted broadly; for example, they may refer to a fixed connection, a detachable connection, or an integral connection; a mechanical connection or an electrical connection; a direct connection or an indirect connection through an intermediate medium; or a connection within two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0022] Example 1 As shown in Figure 1- Figure 3 As shown, this embodiment provides a basic flue gas waste heat recovery device, a flue gas waste heat recovery device for thermal power plants, including a shell 1, a flue gas inlet pipe 2 connected to one side of the shell 1 and a flue gas outlet pipe 3 connected to the other side, an insulation lining 4 fixedly connected to the inner wall of the shell 1, the insulation lining 4 being made of high-temperature resistant rock wool and vacuum insulation board composite, and a heat storage mechanism 5 being provided in the inner cavity of the shell 1.

[0023] like Figures 2-7As shown, the heat storage mechanism 5 includes a support frame 51. The bottom of the support frame 51 is fixedly connected to the heat insulation lining 4. The front end and the rear end of the top of the support frame 51 are respectively fixedly connected to a first outer shell 52 and a second outer shell 53. One side of the first outer shell 52 is connected to a working fluid inlet pipe 54. One side of the working fluid inlet pipe 54 penetrates the shell 1 and extends to the outside. The inner cavity of the first outer shell 52 is fixedly connected to a first straight pipe 55. One side of the first straight pipe 55 is connected to the working fluid inlet pipe 54. The inner cavity of the second outer shell 53 is fixedly connected to a second straight pipe 56. The first straight pipe 55 and the second straight pipe 56 are arranged in parallel. One side of the second straight pipe 56 is connected to the first straight pipe 55, and the other side is connected to a working fluid outlet pipe 57. One side of the working fluid outlet pipe 57 penetrates the shell 1 and extends to the outside. The first straight tube 55 and the second straight tube 56 are both fixedly connected to heat-conducting fins 58. The heat-conducting fins 58 are evenly distributed along the length of the straight tube, and the spacing between adjacent heat-conducting fins 58 is 15mm. The inner cavities of the first outer shell 52 and the second outer shell 53 are both filled with a phase change material layer 59. The phase change material layer 59 is an inorganic hydrated salt phase change material with a melting point of 100℃.

[0024] like Figure 2 , Figure 6 and Figure 7 As shown, a connecting seat 8 is fixedly connected to one side of the first outer shell 52 and the second outer shell 53. A temperature sensor 9 and a pressure sensor 10 are fixedly connected to both sides of the surface of the connecting seat 8, respectively. A water temperature sensor 11 is connected to one side of the surface of the working fluid discharge pipe 57, and an inlet pressure gauge 12 is connected to the surface of the working fluid inlet pipe 54.

[0025] like Figure 4 and Figure 8 As shown, a dust collection hood 13 is connected to the bottom of the housing 1. The dust collection hood 13 is funnel-shaped with a cone angle of 75°, and a control valve 14 is connected to the bottom. A guide plate 18 is fixedly connected to the front and rear ends of the inner wall of the housing 1. The guide plate 18 is inclined and has an angle of 45° with the axis of the housing 1. One side is fixedly connected to the support frame 51.

[0026] The working process of this embodiment is as follows: High-temperature dusty flue gas enters the shell 1 through the flue gas inlet pipe 2. The guide plate 18 guides the flue gas to flow evenly through the areas of the first shell 52 and the second shell 53. The heat insulation lining 4 reduces heat loss. The heat of the flue gas is transferred to the phase change material layer 59 through the shell wall and the heat-conducting fins 58. The phase change material absorbs heat and changes from solid to liquid to store energy. When the flue gas temperature decreases, the phase change material undergoes a reverse phase change to release latent heat, continuously heating the circulating working fluid (synthetic heat transfer oil) flowing through the first straight pipe 55 and the second straight pipe 56. The heated working fluid is discharged through the working fluid discharge pipe 57 for subsequent use. The temperature sensor 9 and the pressure sensor 10 monitor the heat storage status in real time. The dust collection hood 13 collects the settled dust and discharges it at regular intervals through the control valve 14.

[0027] Example 2 like Figure 2 and Figure 3 As shown, this embodiment provides a waste heat recovery device for flue gas with a heat release mechanism. This embodiment adds a heat release mechanism 6 to the basic embodiment 1, while the rest of the structure is the same as that of embodiment 1. The heat release mechanism 6 includes a circulating pump 61, with a base plate 62 fixedly connected to the bottom of the circulating pump 61. The top of the circulating pump 61 is connected to the working fluid discharge pipe 57. A plate heat exchanger 63 is connected to one side of the circulating pump 61. The plate heat exchanger 63 has a detachable structure, and its heat exchange area is adapted to the heat storage power of the heat storage mechanism 5. A working fluid circulation pipe 64 is connected to one side of the plate heat exchanger 63. A three-way valve 65 is connected to the top of the working fluid circulation pipe 64. One side of the three-way valve 65 is connected to the working fluid inlet pipe 54, and the other side is connected to the buffer tank delivery pipe 66. A drain pipe 15 is connected to the top of the other side of the plate heat exchanger 63, and a water inlet pipe 16 is connected to the bottom.

[0028] The working process of this embodiment is as follows: The circulating pump 61 provides power for the circulation of the working fluid. After absorbing heat from the phase change material, the working fluid enters the plate heat exchanger 63 through the working fluid discharge pipe 57, where it exchanges heat with the external cold source medium introduced through the inlet water pipe 16. The heated medium is then discharged through the drain pipe 15 for reuse. The cooled working fluid is then transported to the three-way valve 65 through the working fluid circulation pipe 64. When the external heat demand is stable, the working fluid is returned to the working fluid inlet pipe 54 through the three-way valve 65 to form a closed-loop circulation. When the system load fluctuates, part of the working fluid is introduced into the buffer facility through the buffer tank delivery pipe 66 to ensure stable system operation.

[0029] Example 3 like Figure 1 , Figure 4 and Figure 8 As shown, this embodiment provides a waste heat recovery device for flue gas with a dust removal mechanism. This embodiment adds a dust removal mechanism 7 to the basic embodiment 2, while the rest of the structure is the same as that of embodiment 2. The dust removal mechanism 7 includes a motor 71, one side of which is fixedly connected to the housing 1. A lead screw 72 is fixedly connected to the output end of the motor 71. One side of the lead screw 72 extends into the inner cavity of the housing 1, and a movable frame 73 is threadedly connected to its surface. Slide rods 17 are fixedly connected to both sides of the inner wall of the housing 1, and the surfaces of the slide rods 17 are slidably connected to the movable frame 73. Shock generators 74 are fixedly connected to both sides of the bottom of the movable frame 73. The bottom of the shock generators 74 contacts the first housing 52 and the second housing 53 respectively, with a contact gap of 1 mm.

[0030] The working process of this embodiment is as follows: During the waste heat recovery process, the motor 71 is started, which drives the lead screw 72 to rotate. The moving frame 73 moves horizontally under the guidance of the slide rod 17, which drives the shock wave generator 74 to move along the surface of the first outer shell 52 and the second outer shell 53. The shock wave vibration peels off the attached dust. The peeled dust falls into the dust collection hood 13 and is discharged at regular intervals through the control valve 14. The ash removal can be completed without shutting down the furnace, ensuring stable heat exchange efficiency.

[0031] Example 4 This embodiment provides a fully integrated waste heat recovery device for flue gas and dust. This embodiment integrates the basic structure of Embodiment 1, the heat release mechanism 6 of Embodiment 2, and the dust removal mechanism 7 of Embodiment 3 to form a fully integrated device. The circulating working fluid is synthetic heat transfer oil. The shock wave generator 74 has a 1mm gap with the outer shell surface. The guide plate 18 has a 45° angle with the axis of the shell 1. The phase change material has a melting point of 100℃. The heat-conducting fin spacing is 15mm, and the dust collection hood cone angle is 75°.

[0032] This embodiment discloses a waste heat recovery device for flue gas from a thermal power plant, comprising a shell 1, an inlet pipe 2 connected to one side of the shell 1, an outlet pipe 3 connected to the other side of the shell 1, an insulation lining 4 fixedly connected to the inner wall of the shell 1, and a heat storage mechanism 5 provided in the inner cavity of the shell 1. The heat storage mechanism 5 includes a support frame 51. The bottom of the support frame 51 is fixedly connected to the insulation lining 4. A first outer shell 52 and a second outer shell 53 are fixedly connected to the front and rear ends of the top of the support frame 51, respectively. A working fluid inlet pipe 54 is connected to one side of the first outer shell 52. One side of the working fluid inlet pipe 54 penetrates the inner cavity of the shell 1 and extends to the outside of the shell 1. A first straight pipe 55 is fixedly connected to the inner cavity of the first outer shell 52. One side of the first straight pipe 55 is connected to the working fluid inlet pipe 54. The inner cavity of the second outer shell 53... A second straight pipe 56 is fixedly connected, one side of which is connected to a first straight pipe 55, and the other side of the second straight pipe 55 is connected to a working fluid discharge pipe 57. One side of the working fluid discharge pipe 57 penetrates the inner cavity of the shell 1 and extends to the outside of the shell 1. Heat-conducting fins 58 are fixedly connected to the surfaces of the first straight pipe 55 and the second straight pipe 56. The inner cavities of the first outer shell 52 and the second outer shell 53 are filled with a phase change material layer 59. The bottom of the support frame 51 is fixedly connected to the heat insulation lining 4, serving as a heat storage component. Providing stable support, both the first outer shell 52 and the second outer shell 53 are sealed structures, forming independent heat storage chambers. The working fluid inlet pipe 54 is used to transport the circulating working fluid into the heat storage chamber. The heat-conducting fins 58 are evenly distributed on the surface of the straight pipe to increase the contact area between the straight pipe and the phase change material layer, thereby improving the heat transfer efficiency. The phase change material absorbs and stores the waste heat of the flue gas through the transformation between solid and liquid states, and then transfers the stored heat to the circulating working fluid flowing through the straight pipe. The phase change material has the characteristic of absorbing and releasing a large amount of latent heat under near-constant temperature conditions. When the boiler load changes and causes fluctuations in flue gas temperature and flow rate, the phase change material buffers these fluctuations through the phase change process. When the flue gas temperature is high, the phase change material absorbs the waste heat and transforms into a liquid state to store energy. When the flue gas temperature decreases, the phase change material releases the stored latent heat and transforms into a solid state, continuously providing heat to the circulating working fluid flowing through the straight pipe, so that the output working fluid temperature remains stable. This greatly facilitates the utilization of recovered heat energy in subsequent processes and improves the quality and utilization value of recovered heat energy.

[0033] A heat release mechanism 6 is connected to one side of the shell 1. The heat release mechanism 6 includes a circulating pump 61. A base plate 62 is fixedly connected to the bottom of the circulating pump 61. The top of the circulating pump 61 is connected to the working fluid discharge pipe 57. A plate heat exchanger 63 is connected to one side of the circulating pump 61. A working fluid circulation pipe 64 is connected to one side of the plate heat exchanger 63. A three-way valve 65 is connected to the top of the working fluid circulation pipe 64. One side of the three-way valve 65 is connected to the working fluid inlet pipe 54. The other side of the three-way valve 65 is connected to the buffer tank delivery pipe 66. In this preferred embodiment, the circulating pump 61 provides power, enabling the working fluid, after absorbing the waste heat stored in the phase change material, to be continuously transported to the plate heat exchanger 63. This allows for efficient heat exchange with the external heat medium, achieving directional output and full utilization of the waste heat. The three-way valve 65 provides the system with flexible operational adjustment capabilities, allowing the flow direction of the working fluid or the flow rate to be switched according to the external heat demand and the state of the working fluid within the system. When the external heat demand is stable, the working fluid forms a closed-loop circulation through the connection path between the three-way valve 65 and the working fluid inlet pipe 54, continuously completing the heat absorption and release cycle. When the system load fluctuates or the working fluid pressure is abnormal, a portion of the working fluid is introduced into the buffer facility through the buffer tank delivery pipe 66 to prevent a sudden increase in system pressure or flow fluctuations, ensuring the stable operation of the entire heat exchange system. Meanwhile, the plate heat exchanger 63, as a high-efficiency heat exchange component, can quickly achieve heat transfer between the circulating working fluid and the external heat medium.

[0034] A dust removal mechanism 7 is provided at the top of the inner cavity of the housing 1. The dust removal mechanism 7 includes a motor 71. One side of the motor 71 is fixedly connected to the housing 1. A lead screw 72 is fixedly connected to the output end of the motor 71. One side of the lead screw 72 extends into the inner cavity of the housing 1. A movable frame 73 is threadedly connected to the surface of the lead screw 72. Shock generators 74 are fixedly connected to both sides of the bottom of the movable frame 73. The bottom of the shock generators 74 contacts the first outer shell 52 and the second outer shell 53 respectively. In this preferred embodiment, the motor 71 drives the lead screw 72 to drive the moving frame 73 and the shock wave generator 74 to move smoothly along the surfaces of the first outer shell 52 and the second outer shell 53, achieving comprehensive dust removal of both outer shell surfaces. This avoids the cleaning dead corners that exist in fixed dust removal structures. The shock wave generator 74 is in direct contact with the outer shell surface, and the generated shock wave vibration efficiently peels off the attached dust, preventing the long-term accumulation of dust from forming a heat insulation layer. This ensures that the outer shell can continuously and efficiently transfer the waste heat of the flue gas to the internal phase change material layer, ensuring the stable heat exchange efficiency of the entire heat storage mechanism. The dust removal action and the waste heat recovery process can be carried out simultaneously without stopping the machine for cleaning. This ensures the continuity of the device operation and reduces the frequency of equipment maintenance caused by dust blockage, thus reducing operation and maintenance costs. The translational design of the moving frame 73, combined with the shock wave vibration cleaning method, can effectively remove dust without causing mechanical damage to the first outer shell 52, the second outer shell 53, and the internal phase change material layer 59, thus balancing the dust removal effect and the safety of equipment operation.

[0035] A connecting seat 8 is fixedly connected to one side of both the first outer shell 52 and the second outer shell 53. A temperature sensor 9 and a pressure sensor 10 are fixedly connected to both sides of the surface of the connecting seat 8, respectively. In this preferred embodiment, the temperature sensor 9 captures the temperature change of the phase change material layer 59 in real time, reflecting the heat storage and release state of the phase change material. The pressure sensor 10 can promptly detect pressure fluctuations in the chamber, avoiding pressure anomalies caused by phase change expansion of the phase change material or leakage of the working fluid. The two work together to monitor the core area of ​​the thermal storage, providing reliable data support for system operation and adjustment, preventing equipment damage caused by parameter malfunction, and ensuring the stable and efficient operation of the thermal storage mechanism.

[0036] A water temperature sensor 11 is connected to one side of the working fluid discharge pipe 57, and an inlet pressure gauge 12 is connected to the surface of the working fluid inlet pipe 54. In this preferred embodiment, the water temperature sensor 11 monitors the temperature of the circulating working fluid after heat absorption in real time, intuitively reflecting the actual effect of waste heat recovery, which facilitates the operator to judge whether the output heat energy meets the subsequent heat demand. The inlet pressure gauge 12 on the working fluid inlet pipe 54 can provide real-time feedback on the working fluid pressure status entering the heat storage mechanism, and promptly detect abnormalities such as poor working fluid circulation and pipeline blockage.

[0037] A dust collection hood 13, which is funnel-shaped, is connected to the bottom of the housing 1. A control valve 14 is also connected to the bottom of the dust collection hood 13. In this preferred embodiment, the funnel-shaped dust collection hood utilizes gravity to collect the detached smoke and dust and the dust settled inside the housing in a directional manner, ensuring the cleanliness of the flue gas flow channel and the heat exchange area. The control valve enables timed dust discharge, allowing the dust removal operation to be completed without stopping the machine, thus ensuring the controllability of the dust removal process.

[0038] A drain pipe 15 is connected to the top of the other side of the plate heat exchanger 63, and a water inlet pipe 16 is connected to the bottom of the other side of the plate heat exchanger 63. In this preferred embodiment, the water inlet pipe 16 introduces an external cold source medium into the plate heat exchanger 63, and the drain pipe 15 is used to discharge the hot medium that has been heated after absorbing waste heat, forming an independent flow and heat exchange channel for the cold and hot media in the plate heat exchanger 63, which allows for efficient heat exchange with the circulating working medium, ensuring that the waste heat carried by the circulating working medium is fully transferred to the external heat-using medium, and realizing the directional output and maximum utilization of waste heat.

[0039] Both sides of the inner wall of the housing 1 are fixedly connected to slide rods 17, and the surface of the slide rods 17 is slidably connected to the moving frame 73. In this preferred embodiment, the slide rods 17 and the moving frame 73 are slidably engaged, providing guidance for the translational movement of the moving frame 73 and preventing the moving frame 73 from shaking under the drive of the lead screw 72. This ensures that the shock wave generator 74 can always maintain stable contact with the surfaces of the first housing 52 and the second housing 53, ensuring the effective transmission of shock wave vibration during dust removal and improving the uniformity of dust removal.

[0040] Both the front and rear ends of the inner wall of the shell 1 are fixedly connected to guide plates 18. The guide plates 18 are inclined, and one side of the guide plate 18 is fixedly connected to the support frame 51. In this preferred embodiment, the guide plates 18 can guide and equalize the flow of flue gas entering the shell 1, guiding the flue gas to flow evenly along a preset path through the heat storage mechanism area, avoiding heat exchange dead zones caused by excessively fast or slow local flow rates of the flue gas, and ensuring that all parts of the first shell 52 and the second shell 53 can fully contact the flue gas, thereby improving the uniformity and overall efficiency of waste heat absorption.

[0041] The thermal insulation lining 4 is made of a composite of high-temperature resistant rock wool and vacuum insulation board, and the phase change material layer 59 is made of a phase change material with a melting point of 80-120℃. In this preferred embodiment, the thermal insulation lining made of high-temperature resistant rock wool and vacuum insulation board combines the high-temperature resistance and fire resistance of rock wool with the low thermal conductivity and high thermal insulation advantages of vacuum insulation board. It can effectively prevent heat loss from the shell to the outside, reduce the loss of waste heat during the transfer process, and ensure that the phase change material layer 59 can fully absorb the waste heat of flue gas, thereby improving the overall efficiency of waste heat recovery. The phase change material layer is made of inorganic hydrated salt. Compared with most organic materials, inorganic salts have better thermal conductivity, which is conducive to the rapid entry and exit of heat.

[0042] The working process of this embodiment is as follows: High-temperature dusty flue gas enters the shell 1 through the flue gas inlet pipe 2. The guide plate 18 guides the flue gas to flow evenly through the heat storage mechanism 5, where the phase change material layer 59 absorbs and stores heat. The circulating pump 61 drives the working fluid to circulate between the heat storage mechanism 5 and the plate heat exchanger 63, realizing the directional output of waste heat. The dust removal mechanism 7 operates synchronously, stripping dust from the surface of the shell, and the dust is collected and discharged through the dust collection hood 13. Parameters such as temperature, pressure, and flow rate are monitored in real time by various sensors, and the three-way valve 65 adjusts the flow direction of the working fluid according to the system status to ensure the overall stable and efficient operation of the device.

[0043] This invention effectively solves many of the shortcomings of existing technologies through multi-module integrated design, and can be widely applied to various thermal power plant flue gas waste heat recovery scenarios, significantly improving energy utilization efficiency and reducing environmental pollution and equipment maintenance costs.

[0044] In summary, this invention offers high and stable waste heat recovery efficiency. It utilizes an 80-120℃ inorganic hydrated salt phase change material as the heat storage medium, combined with heat-conducting fins on the surface of straight pipes, to increase the heat exchange contact area and solve the problem of poor thermal conductivity of phase change materials. The phase change material absorbs and releases a large amount of latent heat through solid-liquid phase change, which can buffer changes in flue gas parameters caused by boiler load fluctuations, stabilize the output working fluid temperature, and improve the quality and utilization value of recovered heat energy.

[0045] This invention has a significant effect in preventing dust accumulation. It integrates a translational shock wave dust removal mechanism. The motor-driven moving frame moves the shock wave generator along the entire surface of the outer shell, eliminating cleaning dead corners. The shock wave vibration can efficiently peel off the attached smoke and dust, preventing the formation of a heat insulation layer. Dust removal and waste heat recovery are carried out simultaneously, without the need to shut down the furnace, reducing maintenance costs and preventing mechanical damage to the equipment.

[0046] This invention features excellent corrosion resistance and thermal insulation performance. The thermal insulation lining adopts a composite structure of high-temperature resistant rock wool and vacuum insulation board, which effectively reduces heat loss. The phase change thermal storage mode can avoid excessively low temperature of the heat exchange wall, reduce the risk of low-temperature corrosion, and extend the service life of the equipment.

[0047] This invention features a high degree of functional integration, combining heat storage, heat release, dust removal, and parameter monitoring into a compact structure. The heat release mechanism achieves directional output of waste heat through a circulating pump and plate heat exchanger, while a three-way valve can flexibly adjust the flow direction of the working fluid. The buffer tank delivery pipe ensures stable system pressure. Multiple sensors monitor temperature and pressure parameters in real time, providing reliable data support for operation and regulation.

[0048] This invention boasts high energy utilization and can deeply tap into the waste heat in the medium and low temperature range. Compared with traditional heat exchangers, it is more adaptable to boiler load changes and has higher overall energy efficiency. The funnel-shaped dust collection hood enables directional dust collection and timed emission, ensuring unobstructed flue gas flow and further improving waste heat recovery efficiency.

[0049] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A waste heat recovery device for flue gas from a thermal power plant, characterized in that, The system includes a shell, a heat storage mechanism, a heat release mechanism, and a dust removal mechanism. One side of the shell is connected to an inlet pipe, and the other side is connected to an outlet pipe. An insulating lining is fixed to the inner wall of the shell, and inclined guide plates are fixed to the front and rear ends of the inner wall. The heat storage mechanism includes a support frame, with a first outer shell and a second outer shell fixed to the top of the support frame. Both the first and second outer shells have cavities filled with a phase change material layer, and each has a straight pipe inside. Thermally conductive fins are fixed to the surface of the straight pipe. The first outer shell is connected to a working fluid inlet pipe, and the second outer shell is connected to a working fluid outlet pipe. The two straight pipes are interconnected; the heat release mechanism includes a circulating pump, a plate heat exchanger, and a three-way valve. The circulating pump is connected to the working fluid discharge pipe and the plate heat exchanger. The plate heat exchanger is connected to the three-way valve through the working fluid circulation pipe. The three-way valve is connected to the working fluid inlet pipe and the buffer tank delivery pipe, respectively. The dust removal mechanism includes a motor, a lead screw, a moving frame, and a shock wave generator. The motor drives the lead screw to rotate. The moving frame is threadedly connected to the lead screw and its bottom is connected to the shock wave generator. The shock wave generator is in contact with the surfaces of the first outer shell and the second outer shell.

2. The waste heat recovery device for flue gas from thermal power plants according to claim 1, characterized in that, The thermal insulation lining is made of high-temperature resistant rock wool and vacuum insulation board, and the phase change material layer is made of inorganic hydrated salt phase change material with a melting point of 80-120℃.

3. The waste heat recovery device for flue gas from thermal power plants according to claim 1, characterized in that, Both the first and second housings have fixed connecting seats on one side, and a temperature sensor and a pressure sensor are respectively fixed on the surface of the connecting seats; the working fluid discharge pipe is connected to a water temperature sensor, and the working fluid inlet pipe is connected to an inlet pressure gauge.

4. The waste heat recovery device for flue gas from thermal power plants according to claim 1, characterized in that, The bottom of the housing is connected to a funnel-shaped dust collection hood, and the bottom of the dust collection hood is connected to a control valve; sliding rods are fixed on both sides of the inner wall of the housing, and the sliding rods are slidably connected to the movable frame.

5. The waste heat recovery device for flue gas from thermal power plants according to claim 1, characterized in that, The first housing has a first straight tube inside, and the second housing has a second straight tube inside. The first and second straight tubes are arranged in parallel. The heat-conducting fins are evenly distributed along the length of the straight tubes, and the spacing between adjacent heat-conducting fins is 10-20 mm. The gap between the shock wave generator and the surfaces of the first and second housings does not exceed 2 mm.

6. The waste heat recovery device for flue gas from thermal power plants according to claim 1, characterized in that, The plate heat exchanger has a detachable structure. The top of the other side of the plate heat exchanger is connected to a drain pipe, and the bottom of the plate heat exchanger is connected to a water inlet pipe. The angle between the guide plate and the axis of the shell is 30-60°.

7. The waste heat recovery device for flue gas from thermal power plants according to claim 1, characterized in that, The cone angle of the dust collection hood is 60-90°; the circulating working fluid is synthetic heat transfer oil.

8. The waste heat recovery device for flue gas from thermal power plants according to claim 1, characterized in that, The heat exchange area of ​​the plate heat exchanger is adapted to the heat storage power of the heat storage mechanism; the three-way valve switches the working fluid flow direction according to the system load.

9. A method for recovering waste heat from flue gas in a thermal power plant, characterized in that, The device according to any one of claims 1-8 is implemented by comprising the following steps: S1. High-temperature dust-laden flue gas enters the casing through the flue pipe, and the guide plate guides the flue gas to flow evenly through the first and second outer casing areas; S2. The heat from the flue gas is transferred to the phase change material layer through the outer shell wall and heat-conducting fins. The phase change material absorbs heat and undergoes a phase change to store energy, or undergoes a reverse phase change to release latent heat and heat the circulating working fluid. S3. The circulating pump drives the working fluid to circulate between the heat storage mechanism and the plate heat exchanger, and the working fluid exchanges heat with the external medium to realize the utilization of waste heat. S4. The dust removal mechanism operates synchronously. The motor drives the shock wave generator to move along the surface of the outer shell, stripping off the smoke and dust, which is then collected and discharged by the dust collection hood.

10. The method for recovering waste heat from flue gas in a thermal power plant according to claim 9, characterized in that, In step S2, the thermal storage status is monitored in real time by temperature and pressure sensors; in step S3, the three-way valve enables the working fluid to form a closed loop circulation when the external heat demand is stable, and introduces part of the working fluid into the buffer facility when the system load fluctuates; in step S4, the smoke and dust are discharged in a timely manner through the control valve without the need to stop the machine for cleaning.

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