Low-temperature flue gas waste heat recovery device of waste incineration plant

Abstract

The application provides a low-temperature flue gas waste heat recovery device for a waste incineration plant, comprising: a cyclone dust collector installed at a flue gas outlet of the waste incineration plant, used for dust removal treatment of the discharged flue gas; a neutralization control assembly installed at an outlet of the cyclone dust collector, used for acid neutralization of the dust removal treated flue gas, and obtaining neutralized flue gas; a first waste heat recovery assembly installed outside the cyclone dust collector, used for recovering heat in the flue dust; a second waste heat recovery assembly installed outside the neutralization control assembly, used for recovering heat in the acid gas neutralization process; a third waste heat recovery assembly installed inside the neutralization control assembly, used for recovering heat of the neutralized flue gas; and a heat energy utilization assembly connected with the first, second and third waste heat recovery assemblies respectively, to utilize the recovered heat. The application effectively improves the heat recovery efficiency of the flue gas generated by waste incineration.

Description

Technical Field

[0001] This invention belongs to the field of waste incineration technology, and in particular relates to a low-temperature flue gas waste heat recovery device for waste incineration plants. Background Technology

[0002] Waste incineration is a process in which waste is reduced in volume through appropriate thermal decomposition, combustion, melting and other reactions, and then oxidized at high temperatures to become residue or molten solid matter.

[0003] Waste incineration facilities must be equipped with flue gas treatment facilities to prevent heavy metals, organic pollutants, and other contaminants from being released back into the environment. Recovering the heat generated from waste incineration can achieve the goal of waste resource utilization.

[0004] Waste incineration is an older and traditional method of waste disposal. Because incineration significantly reduces waste volume, saves land, eliminates pathogens, and transforms toxic and harmful substances into harmless ones, it has become one of the main methods of urban waste management. Modern waste incinerators are equipped with advanced flue gas purification systems to reduce air pollution.

[0005] Even after desulfurization and denitrification, the flue gas from waste incineration plants still carries a large amount of low-temperature waste heat (around 140°C). Traditional processes directly discharge this heat through the chimney, resulting in energy waste. Existing waste heat recovery technologies also employ a single recovery mode, leading to a low heat recovery rate. Furthermore, the acidic gases in the flue gas cause equipment to corrode easily, affecting the equipment's service life. Summary of the Invention

[0006] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide a low-temperature flue gas waste heat recovery device for waste incineration plants, which solves the problem of low efficiency in the recovery of flue gas waste heat after waste incineration in the prior art.

[0007] To achieve the above and other related objectives, the present invention provides a low-temperature flue gas waste heat recovery device for a waste incineration plant, comprising:

[0008] A cyclone dust collector is installed at the flue gas outlet of a waste incineration plant to remove dust from the discharged flue gas. A neutralization control component is installed at the outlet of the cyclone dust collector to neutralize the acidity of the flue gas after dust removal and obtain neutralized flue gas. The first waste heat recovery component is installed outside the cyclone dust collector to recover heat from the flue gas. The second waste heat recovery component is installed outside the neutralization and control component and is used to recover heat during the neutralization process of acid gas. The third waste heat recovery component is installed inside the neutralization and control component and is used to recover the heat of the neutralized flue gas. A thermal energy utilization component is connected to the first waste heat recovery component, the second waste heat recovery component, and the third waste heat recovery component, respectively, to utilize the recovered heat. The heat energy utilization component includes a first heat exchanger connected in conductive connection to the first waste heat recovery component, a second heat exchanger connected in conductive connection to the second waste heat recovery component, and a third heat exchanger connected in conductive connection to the third waste heat recovery component.

[0009] In one embodiment of the present invention, the cyclone dust collector includes a cyclone bucket, an air inlet pipe is installed at the top of the cyclone bucket, the air inlet pipe is used to input the incineration flue gas from the waste incineration plant into the interior of the cyclone bucket, a cyclone fan is installed outside the cyclone bucket, and an ash collection trough is installed at the bottom of the cyclone bucket, the ash collection trough is used to collect the separated dust.

[0010] In one embodiment of the present invention, the first waste heat recovery assembly includes a rotating cylinder installed inside the ash collection trough. A plurality of hollow heat-conducting plates are electrically connected to the outer wall of the rotating cylinder. A sliding plate is disposed between adjacent heat-conducting plates. Both ends of the sliding plate are slidably connected to the heat-conducting plates via flexible components. A first push rod is connected to one end of each heat-conducting plate. The end of the first push rod is fixedly connected to the rotating cylinder, so as to push the sliding plate to move inside the ash collection trough. Coolant is contained inside the heat-conducting plates. A first heat exchanger is electrically connected to the rotating cylinder, so as to transfer the coolant that absorbs heat inside the heat-conducting plates to the first heat exchanger for heat exchange, thereby recovering the heat inside the heat-conducting plates.

[0011] In one embodiment of the present invention, the neutralization and control component includes a regulating box installed at the outlet of the swirl bucket. Multiple first and second concentrated buckets are sequentially spaced inside the regulating box. A first nozzle is installed at the top of the first concentrated bucket and a gap is formed between the top and the regulating box. A second nozzle is installed at the bottom of the second concentrated bucket and a gap is formed between the bottom and the regulating box. A flow channel is formed between the sides of the first and second concentrated buckets. The first and second nozzles are used to spray an alkaline solution to neutralize the acidic gases in the flue gas. Gas entering the regulating box passes through the multiple flow channels sequentially and is discharged from the outlet outside the regulating box.

[0012] In one embodiment of the present invention, both the first nozzle and the second nozzle adopt an annular structure.

[0013] In one embodiment of the present invention, the second waste heat recovery component is installed on the inner wall of the flow channel. The second waste heat recovery component includes a guide pipe embedded in the inner wall of the flow channel. A plurality of heat exchange fins are conductively connected to the outside of the guide pipe. The heat exchange fins are disposed on the outer wall of the flow channel and are arranged along the axial direction of the flow channel. The top end of the guide pipe is conductively connected to the second heat exchanger. The second heat exchanger is used to absorb heat from the coolant that is absorbed and evaporated inside the heat exchange fins.

[0014] In one embodiment of the present invention, the third waste heat recovery assembly includes a heat recovery cylinder installed outside the regulating box. A gas collecting hopper is installed inside the heat recovery cylinder. The top of the gas collecting hopper is connected to an outlet outside the regulating box via a connecting pipe. A flexible sealing gasket is installed inside the gas collecting hopper. A movable push rod inserted into the bottom of the gas collecting hopper is connected to the bottom of the flexible sealing gasket, so that the flexible sealing gasket slides up and down along the inner wall of the gas collecting hopper via the movable push rod. Multiple air holes are evenly arranged on both sides of the inner wall of the gas collecting hopper. Each air hole is externally connected to a first heat-conducting pipe. Multiple first heat-conducting pipes are connected to second heat-conducting pipes. The heat recovery cylinder is filled with coolant. The first and second heat-conducting pipes are immersed in the coolant to transfer heat from the flue gas to the coolant. The heat recovery cylinder is connected to the third heat exchanger to transfer the heat-absorbing coolant to the third heat exchanger for heat exchange.

[0015] In one embodiment of the present invention, the air holes are distributed in a U-shape along the inner wall of the air collecting hopper to form a plurality of first U-shapes arranged vertically, and the bottom height of the first U-shape formed by the air holes in the upper layer is higher than the height of the first U-shape formed by the air holes in the lower layer. The vertical cross section of the flexible sealing gasket is an inverted U-shape. The first U-shape and the inverted U-shape are mirror images of each other, and the inner diameter of the plurality of air holes increases linearly from both sides to the middle.

[0016] In one embodiment of the present invention, the first heat exchanger, the second heat exchanger and the third heat exchanger are all connected by a mixing pipe. The mixing pipe is used to open the valve of each heat exchanger to control the mixing of hot water at different temperatures to form hot water at the corresponding temperature. The heating solution in the mixing pipe is used to preheat the combustion air or heat the ammonia solution.

[0017] As described above, the low-temperature flue gas waste heat recovery device for waste incineration plants of the present invention has the following beneficial effects: This invention uses a cyclone dust collector to treat the flue gas generated from waste incineration to remove dust. A first waste heat recovery component recovers heat from the dust, while a neutralization and regulation component neutralizes acidic gases in the flue gas to reduce corrosion of the equipment. A second waste heat recovery component recovers heat from the neutralization process, and a third waste heat recovery component collects and recovers the remaining heat after neutralization. This allows for the phased recovery of heat from the flue gas generated from waste incineration, effectively improving heat recovery efficiency and reducing the impact of dust and acidic gases on the equipment, thus extending its service life. Attached Figure Description

[0018] Figure 1 The diagram shown is a structural schematic of a low-temperature flue gas waste heat recovery device for a waste incineration plant according to an embodiment of the present invention.

[0019] Figure 2 The diagram shown is a cross-sectional structural schematic of the rotating cylinder in the low-temperature flue gas waste heat recovery device for a waste incineration plant according to the present invention.

[0020] Figure 3 The diagram shown is an enlarged structural schematic of A in the low-temperature flue gas waste heat recovery device of the waste incineration plant according to the present invention.

[0021] Figure 4 The diagram shows the arrangement of pores in the low-temperature flue gas waste heat recovery device for a waste incineration plant according to the present invention. Detailed Implementation

[0022] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, unless otherwise specified, the following embodiments and features described therein can be combined with each other.

[0023] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. The illustrations only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0024] The low-temperature flue gas waste heat recovery device for waste incineration plants of the present invention uses a cyclone dust collector to treat the flue gas generated by waste incineration to remove dust. A first waste heat recovery component recovers the heat from the dust, while a neutralization and regulation component neutralizes acidic gases in the flue gas to reduce the corrosive effect of subsequent flue gas on the equipment. A second waste heat recovery component recovers the heat generated during the flue gas neutralization process. After neutralization, a third waste heat recovery component collects and recovers the heat from the neutralized flue gas. This allows for the phased recovery of heat from the flue gas generated by waste incineration, effectively improving heat recovery efficiency and reducing the impact of dust and acidic gases in the flue gas on the equipment, thus extending the equipment's service life.

[0025] like Figures 1 to 4 As shown, in one embodiment, the present invention provides a low-temperature flue gas waste heat recovery device for a waste incineration plant, comprising: Cyclone dust collector 1 is installed at the flue gas outlet of the waste incineration plant to remove dust from the discharged flue gas. Neutralization control component 2 is installed at the outlet of the cyclone dust collector 1 to neutralize the acidity of the flue gas after dust removal and obtain neutralized flue gas. The first waste heat recovery component 3 is installed outside the cyclone dust collector 1 to recover heat from the flue gas. The second waste heat recovery component 4 is installed outside the neutralization and control component 2 and is used to recover heat during the neutralization process of acid gas. The third waste heat recovery component 5 is installed inside the neutralization and control component 2 and is used to recover the heat of the neutralized flue gas. The heat energy utilization component 6 is connected to the first waste heat recovery component 3, the second waste heat recovery component 4 and the third waste heat recovery component 5 respectively, so as to utilize the recovered heat. The thermal energy utilization component 6 includes a first heat exchanger 61 connected to the first waste heat recovery component 3, a second heat exchanger 62 connected to the second waste heat recovery component 4, and a third heat exchanger 63 connected to the third waste heat recovery component 5.

[0026] In this embodiment, for the flue gas generated by the waste incineration plant, a cyclone dust collector 1 is first used to remove dust from the flue gas, thereby preventing dust accumulation and affecting the waste heat recovery efficiency of the equipment. The removed dust is then recovered through the first waste heat recovery component 3, achieving the first recovery of flue gas heat. Subsequently, an alkaline solution is sprayed from the neutralization control component 2 to neutralize the acidic gases in the flue gas, effectively removing the acidic gases and preventing corrosion of the equipment. The heat generated during the neutralization process is recovered through the second waste heat recovery component 4, achieving the second recovery of flue gas heat. Finally, for the gas that has undergone acid-base neutralization, a third waste heat recovery component 5 is used to achieve the third recovery of flue gas heat, further absorbing the residual heat in the flue gas and improving the flue gas heat recovery efficiency.

[0027] In some embodiments, the cyclone dust collector 1 includes a cyclone bucket 11, an air inlet pipe 12 is installed at the top of the cyclone bucket 11, the air inlet pipe 12 is used to input the incineration flue gas from the waste incineration plant into the cyclone bucket 11, a cyclone fan 13 is installed outside the cyclone bucket 11, and an ash collection trough 14 is installed at the bottom of the cyclone bucket 11, the ash collection trough 14 is used to collect the separated dust.

[0028] In this embodiment, for the incineration flue gas generated by the waste incineration plant, the flue gas is first input into the cyclone bucket 11 through the air inlet pipe 12. After the cyclone fan 13 installed on the top of the cyclone bucket 11 generates airflow, it exerts a force on the inside of the cyclone bucket 11, causing the airflow to rotate. Under the action of centrifugal force, the soot in the flue gas collides with the inner wall of the cyclone bucket 11 and enters the ash collection tank 14 along the inner wall of the cyclone bucket 11, thereby removing the soot remaining in the flue gas. The flue gas after removing the soot is discharged through the outlet outside the cyclone bucket 11, which facilitates the subsequent further treatment of the flue gas.

[0029] In some embodiments, reference Figure 2 The first waste heat recovery assembly 3 includes a rotating cylinder 31 installed inside the ash collection trough 14. The outer wall of the rotating cylinder 31 is electrically connected to a plurality of hollow heat-conducting plates 32. A sliding plate 33 is provided between adjacent heat-conducting plates 32. Both ends of the sliding plate 33 are slidably connected to the heat-conducting plates 32 through flexible members 34. A first push rod 35 is connected to one end of the heat-conducting plate 32. The end of the first push rod 35 is fixedly connected to the rotating cylinder 31 so as to push the sliding plate 33 to move inside the ash collection trough 14. The heat-conducting plate 32 is filled with coolant. The first heat exchanger 61 is electrically connected to the rotating cylinder 31 so as to transfer the coolant that absorbs heat inside the heat-conducting plate 32 to the first heat exchanger 61 for heat exchange to recover the heat inside the heat-conducting plate 32.

[0030] In this embodiment, after the flue gas generated from waste incineration is separated into dust, the heat in the dust is absorbed by the first waste heat recovery component 3, thereby improving the efficiency of flue gas heat recovery. Specifically, since the dust separated from the flue gas continuously accumulates inside the ash collection tank 14, as the dust accumulates inside the ash collection tank 14, the accumulated dust continuously contacts the heat-conducting plate 32 connected to the outside of the rotating cylinder 31 located inside the ash collection tank 14. The heat from the dust is absorbed by the coolant inside the heat-conducting plate 32, and then the heat-carrying coolant is transferred to the first heat exchanger 61 through the rotating cylinder 31, thereby achieving heat recovery. The first heat exchanger 61 collects the recovered heat for subsequent secondary use.

[0031] In some other embodiments, the neutralization and control component 2 includes a regulating box 21 installed at the outlet of the swirl bucket 11. Multiple first concentrators 22 and second concentrators 23 are sequentially spaced inside the regulating box 21. A first nozzle 25 is installed at the top of the first concentrator 22 and a gap is formed between the top and the regulating box 21. A second nozzle 26 is installed at the bottom of the second concentrator 23 and a gap is formed between the bottom and the regulating box 21. A flow channel 24 is formed between the sides of the first concentrator 22 and the second concentrator 23. The first nozzle 26 and the second nozzle 26 are used to spray an alkaline solution to neutralize the acidic gases in the flue gas. Gas entering the regulating box 21 passes through the multiple flow channels 24 sequentially and is then discharged from the outlet outside the regulating box 21.

[0032] In this embodiment, after the flue gas undergoes dust separation, to further recover the heat, a regulating box 21 is connected to the outlet of the cyclone bucket 11. Since the regulating box 21 is internally equipped with multiple first concentrators 22 and second concentrators 23 evenly spaced, and the first concentrators 22 and second concentrators 23 are trapezoidal structures that are mirror images of each other, with the top opening of the first concentrator 22 being smaller than its bottom opening, and the top opening of the second concentrator 23 being larger than its bottom opening, the flue gas, after entering the regulating box 21, sequentially passes through the flow channel 24 formed between adjacent first concentrators 22 and second concentrators 23. First nozzles 25 and second nozzles 26 are respectively installed at the top of the first concentrators 22 and the bottom of the second concentrators 23. When the airflow passes through the flow channel 24, it is neutralized by alkaline solutions sprayed from the multiple first nozzles 25 and second nozzles 26, thereby effectively removing acidic gases from the flue gas and reducing the corrosive effect of acidic gases on the equipment.

[0033] Furthermore, since the airflow continuously passes through multiple flow channels 24 inside the regulating box 21, as well as the first nozzle 25 installed at the top of the first concentrator 22 and the second nozzle 26 installed at the bottom of the second concentrator 23, the airflow can fully contact the alkaline solution sprayed by the first nozzle 25 and the second nozzle 26 to neutralize it, thereby improving the neutralization effect on acidic gases.

[0034] Furthermore, both the first nozzle 25 and the second nozzle 26 adopt an annular structure, thereby enabling the alkaline solution sprayed by the first nozzle 25 and the second nozzle 26 to cover a wider area, thus improving the neutralization effect on acidic gases.

[0035] In some other embodiments, the second waste heat recovery component 4 is installed on the inner wall of the flow channel 24. The second waste heat recovery component 4 includes a guide pipe 41 embedded in the inner wall of the flow channel 24. The guide pipe 41 is externally connected to a plurality of heat exchange fins 42. The heat exchange fins 42 are disposed on the outer wall of the flow channel 24 and are arranged along the axial direction of the flow channel 24. The top end of the guide pipe 41 is connected to the second heat exchanger 62. The second heat exchanger 62 is used to absorb the heat in the coolant that is absorbed and evaporated inside the heat exchange fins 42.

[0036] In this embodiment, when an alkaline solution is used to neutralize acidic gases in flue gas, the acidic gases themselves carry heat, and heat is also generated during the acid-base neutralization process. To further recover this heat, a guide pipe 41 is installed on the inner wall of the flow channel 24, and multiple heat exchange fins 42 are connected to the outside of the guide pipe 41. After the alkaline solution neutralizes the acidic gases, the resulting neutralized solution flows downward along the inner wall of the flow channel 24. The neutralized solution carrying heat comes into contact with the heat exchange fins 42 on the outer wall of the flow channel 24, and the heat is absorbed by the coolant in the heat exchange fins 42. The cooled liquid evaporated by the heat enters the interior of the guide pipe 41, and the heat inside the guide pipe 41 is further recovered through the second heat exchanger 62. This achieves heat recovery during the acid-base neutralization process and improves the efficiency of heat energy utilization.

[0037] In some other embodiments, the third waste heat recovery assembly 5 includes a heat recovery cylinder 51 installed outside the regulating box 21. A gas collecting hopper 52 is installed inside the heat recovery cylinder 51. The top of the gas collecting hopper 52 is connected to an outlet outside the regulating box 21 via a connecting pipe 53. A flexible sealing gasket 58 is installed inside the gas collecting hopper 52. A movable push rod 54, inserted into the bottom of the gas collecting hopper 52, is connected to the bottom of the flexible sealing gasket 58. The movable push rod 54 drives the flexible sealing gasket 58 to slide up and down along the inner wall of the gas collecting hopper 52. Positioning points are evenly arranged on both sides of the inner wall of the gas collecting hopper 52. Multiple air holes 56 on both sides of the partition plate 55 are provided, each of which is externally connected to a first heat-conducting pipe 57. The multiple first heat-conducting pipes 57 are all connected to second heat-conducting pipes 55. The heat recovery cylinder 51 is filled with coolant. The first heat-conducting pipes 57 and the second heat-conducting pipes 55 are immersed in the coolant to transfer heat from the flue gas to the coolant. The heat recovery cylinder 57 is connected to the third heat exchanger 63 to transfer the coolant that has absorbed heat to the third heat exchanger 63 for heat exchange.

[0038] In this embodiment, the gas that has undergone acid-base neutralization is fed into the gas collection hopper 52 inside the heat recovery cylinder 51 via the connecting pipe 53, and then discharged from multiple gas holes 56 on both sides of the gas collection hopper 52. A first heat-conducting pipe 57 located inside the heat recovery cylinder 51 is connected to the outside of the gas holes 56. After the first heat-conducting pipe 57 is connected to a second heat-conducting pipe 55, the gas that has undergone heat recovery is discharged through the second heat-conducting pipe 55. Heat is transferred to the coolant inside the heat recovery cylinder 51 using the first heat-conducting pipe 57 and the second heat-conducting pipe 55, thus completing the heat recovery process. The coolant inside the heat recovery cylinder 57 absorbs heat and undergoes heat exchange through a third heat exchanger 63, thereby transferring and storing the heat in the third heat exchanger 63.

[0039] It should be noted that the first heat exchanger 61, the second heat exchanger 62, and the third heat exchanger 63 used in the above process are fluoroplastic composite heat exchangers (PTFE coated steel pipes), which have good corrosion resistance and extend service life.

[0040] It should be noted that the first heat exchanger 61, the second heat exchanger 62 and the third heat exchanger 63 used in this application all adopt heat exchanger technology in the prior art. This application does not involve any improvement to the heat exchanger itself. Any heat exchanger in the prior art that can achieve the function of this application can be applied to this application, and will not be described in detail here.

[0041] In some further embodiments, reference is made to Figure 4 The air holes 56 are distributed in a U-shape along the inner wall of the air collecting hopper 52, forming multiple first U-shapes arranged vertically. The bottom height of the first U-shape formed by the air holes 56 in the upper layer is higher than the height of the first U-shape formed by the air holes 56 in the lower layer. The vertical cross-section of the flexible sealing gasket 53 is an inverted U-shape. The first U-shape and the inverted U-shape are mirror images of each other. The inner diameter of the multiple air holes 56 increases linearly from both sides to the middle.

[0042] In this embodiment, when heat is recovered on the inner wall of the gas collecting hopper 52, the heat-carrying airflow is sent into the first heat-conducting pipe 57 and the second heat-conducting pipe 58 located in the coolant through the installed air holes 56 to achieve heat recovery. In order to further ensure the efficiency of heat recovery, the flexible sealing gasket 53 is set as an inverted U-shape, and the air holes 56 are set as multiple layers, with each layer of air holes 56 distributed in a U-shape to form multiple vertically arranged first U-shapes. The inverted U-shape and the first U-shape of the flexible sealing gasket 53 are mirror images of each other, so that as the sliding cover moves downward, the air holes 56 on each layer of the first U-shape will be gradually exposed. The height of the flexible sealing gasket 53 can be adjusted as needed using the movable push rod 54 to expose the air holes 56 at different positions so that the heat-carrying flue gas can enter. The number of exposed air holes 56 can be adjusted according to the actual situation.

[0043] Furthermore, due to the first U-shape formed by the pores 56 in each layer, the inner diameter of the pores 56 gradually increases from both sides to the middle. As the inverted U-shaped flexible sealing gasket 53 moves downward, it gradually exposes the pores 56 of each layer from both sides to the middle. Since the inner diameter of the pores 56 gradually decreases from both sides to the middle, the inner diameter of the gradually exposed pores 56 gradually increases. The position of the flexible sealing gasket 53 can be adjusted according to the flow rate and temperature of the flue gas that needs to recover heat, so as to control the size of the exposed pores 56, thereby controlling the amount of flue gas entering the first heat pipe 57 and the second heat pipe 58, meeting the heat recovery requirements of flue gas with different flow rates and temperatures, and is suitable for various different conditions.

[0044] In some embodiments, the first heat exchanger 61, the second heat exchanger 62, and the third heat exchanger 63 are all connected by a mixing pipe 64. The mixing pipe 64 is used to open the valve of each heat exchanger to control the mixing of hot water at different temperatures to form hot water at the corresponding temperature. The heating solution in the mixing pipe 64 is used to preheat the combustion air or heat the ammonia solution.

[0045] Furthermore, after the heat is received by the first heat exchanger 61, the second heat exchanger 62, and the third heat exchanger 63 respectively, the hot water at different temperatures is mixed together to form a heating solution at the target temperature. This allows the heating solution at different temperatures inside the mixing tube 64 to preheat the combustion air of the waste incineration plant or to heat the ammonia solution or desalination solution, thereby achieving effective utilization of the recovered heat.

[0046] In summary, the low-temperature flue gas waste heat recovery device for waste incineration plants described in this invention uses a cyclone dust collector to treat the flue gas generated from waste incineration to remove dust. A first waste heat recovery component recovers heat from the dust, while a neutralization and regulation component neutralizes acidic gases in the flue gas to reduce corrosion of the equipment by subsequent flue gas. A second waste heat recovery component recovers heat from the flue gas neutralization process, and a third waste heat recovery component collects and recovers the heat from the neutralized flue gas after neutralization. This allows for the phased recovery of heat from the flue gas generated from waste incineration, effectively improving heat recovery efficiency and reducing the impact of dust and acidic gases in the flue gas on the equipment, thus extending the equipment's service life. Therefore, this invention effectively overcomes the various shortcomings of existing technologies and has high industrial application value.

[0047] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A low-temperature flue gas waste heat recovery device for a waste incineration plant, characterized in that, include: A cyclone dust collector is installed at the flue gas outlet of a waste incineration plant to remove dust from the discharged flue gas. A neutralization control component is installed at the outlet of the cyclone dust collector to neutralize the acidity of the flue gas after dust removal and obtain neutralized flue gas. The first waste heat recovery component is installed outside the cyclone dust collector to recover heat from the flue gas. The second waste heat recovery component is installed outside the neutralization and control component and is used to recover heat during the neutralization process of acid gas. The third waste heat recovery component is installed inside the neutralization and control component and is used to recover the heat of the neutralized flue gas. A thermal energy utilization component is connected to the first waste heat recovery component, the second waste heat recovery component, and the third waste heat recovery component, respectively, to utilize the recovered heat. The heat energy utilization component includes a first heat exchanger connected in communication with the first waste heat recovery component, a second heat exchanger connected in communication with the second waste heat recovery component, and a third heat exchanger connected in communication with the third waste heat recovery component. The cyclone dust collector includes a cyclone bucket, an air inlet pipe is installed at the top of the cyclone bucket, the air inlet pipe is used to input the incineration flue gas from the waste incineration plant into the cyclone bucket, a cyclone fan is installed outside the cyclone bucket, and an ash collection trough is installed at the bottom of the cyclone bucket, the ash collection trough is used to collect the separated dust. The neutralization and control assembly includes a regulating box installed at the outlet of the swirl bucket. Multiple first and second concentrated buckets are sequentially spaced inside the regulating box. A first nozzle is installed at the top of the first concentrated bucket and a gap is formed between the top and the regulating box. A second nozzle is installed at the bottom of the second concentrated bucket and a gap is formed between the bottom and the regulating box. A flow channel is formed between the sides of the first and second concentrated buckets. The first and second nozzles are used to spray an alkaline solution to neutralize the acidic gases in the flue gas. Gas entering the regulating box passes through the multiple flow channels sequentially and is then discharged from the outlet outside the regulating box. The third waste heat recovery component includes a heat recovery cylinder installed outside the regulating box. A gas collection hopper is installed inside the heat recovery cylinder. The top of the gas collection hopper is connected to an outlet outside the regulating box via a connecting pipe. A flexible sealing gasket is installed inside the gas collection hopper. A movable push rod inserted into the bottom of the gas collection hopper is connected to the bottom of the flexible sealing gasket, allowing the flexible sealing gasket to slide up and down along the inner wall of the gas collection hopper via the movable push rod. Multiple air holes are evenly arranged on both sides of the inner wall of the gas collection hopper. Each air hole is externally connected to a first heat-conducting pipe. All first heat-conducting pipes are connected to second heat-conducting pipes. The heat recovery cylinder is filled with coolant. The first and second heat-conducting pipes are immersed in the coolant to transfer heat from the flue gas to the coolant. The heat recovery cylinder is connected to the third heat exchanger to transfer the heat-absorbing coolant to the third heat exchanger for heat exchange.

2. The low-temperature flue gas waste heat recovery device for a waste incineration plant according to claim 1, characterized in that, The first waste heat recovery assembly includes a rotating cylinder installed inside the ash collection trough. Multiple hollow heat-conducting plates are electrically connected to the outer wall of the rotating cylinder. Slide plates are positioned between adjacent heat-conducting plates, with both ends of the slide plates slidably connected to the heat-conducting plates via flexible components. A first push rod is connected to one end of each heat-conducting plate, and the end of the first push rod is fixedly connected to the rotating cylinder. The first push rod pushes the slide plate to move within the ash collection trough. Coolant is contained inside the heat-conducting plates. A first heat exchanger is electrically connected to the rotating cylinder to transfer the coolant, which absorbs heat inside the heat-conducting plates, to the first heat exchanger for heat exchange, thereby recovering the heat from the heat-conducting plates.

3. The low-temperature flue gas waste heat recovery device for a waste incineration plant according to claim 1, characterized in that, Both the first nozzle and the second nozzle adopt an annular structure.

4. The low-temperature flue gas waste heat recovery device for a waste incineration plant according to claim 1, characterized in that, The second waste heat recovery component is installed on the inner wall of the flow channel. The second waste heat recovery component includes a guide pipe embedded in the inner wall of the flow channel. Multiple heat exchange fins are connected to the outside of the guide pipe. The heat exchange fins are disposed on the outer wall of the flow channel and are arranged along the axial direction of the flow channel. The top end of the guide pipe is connected to the second heat exchanger. The second heat exchanger is used to absorb heat from the coolant that is absorbed and evaporated inside the heat exchange fins.

5. The low-temperature flue gas waste heat recovery device for a waste incineration plant according to claim 1, characterized in that, The air holes are distributed in a U-shape along the inner wall of the air collecting hopper, forming multiple first U-shapes arranged vertically. The bottom height of the first U-shape formed by the air holes in the upper layer is higher than the height of the first U-shape formed by the air holes in the lower layer. The vertical cross-section of the flexible sealing gasket is an inverted U-shape. The first U-shape and the inverted U-shape are mirror images of each other, and the inner diameter of the multiple air holes increases linearly from both sides to the middle.

6. The low-temperature flue gas waste heat recovery device for a waste incineration plant according to claim 1, characterized in that, The first heat exchanger, the second heat exchanger, and the third heat exchanger are all connected by a mixing pipe. The mixing pipe is used to open the valve of each heat exchanger to control the mixing of hot water at different temperatures to form hot water at the corresponding temperature. The heating solution in the mixing pipe is used to preheat the combustion air or heat the ammonia solution.

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