Waste heat utilization boiler flue gas white smoke elimination system

Abstract

The utility model discloses a waste heat utilization boiler flue gas white smoke elimination system, which is characterized in that a first flue gas heat exchanger and a second flue gas heat exchanger are arranged on an exhaust flue, the waste heat utilization boiler flue gas white smoke elimination system further comprises a waste heat utilization refrigerating machine, and the waste heat utilization refrigerating machine comprises an evaporator, a generator, a condenser and an absorber. A first intermediate medium cycle used for heat transfer is arranged between the first flue gas heat exchanger and the evaporator, a second intermediate medium cycle used for heat transfer is formed between the second flue gas heat exchanger and the waste heat utilization refrigerator, and the second flue gas heat exchanger is arranged at the rear end of the first flue gas heat exchanger; the first flue gas heat exchanger cools flue gas, and the second flue gas heat exchanger heats the flue gas. According to the system, flue gas is firstly cooled by the first flue gas heat exchanger, so that the water content in the flue gas is greatly reduced; the smoke enters the second heat exchanger to be heated, the purpose of white smoke elimination is achieved after the temperature of the smoke rises, latent heat energy in the smoke is used as a driving heat source of the waste heat refrigerating machine, and energy consumption is effectively reduced.

Description

Technical Field

[0001] This utility model relates to the field of energy utilization technology, specifically to a waste heat utilization boiler flue gas whitening system. Background Technology

[0002] Waste heat recovery boiler technology in power plants is one of the important means to improve energy efficiency, reduce energy waste, and mitigate environmental impact. In traditional thermal power generation, the heat generated by burning fuels (such as coal, natural gas, and oil) is used to produce steam, which drives turbines to generate electricity. However, not all the heat generated is effectively utilized; some heat is released into the environment as waste gas, resulting in energy waste.

[0003] Waste heat recovery boilers can effectively extract heat from waste heat streams at different temperature levels and convert it into useful forms, such as preheating feedwater, heating air, or directly generating additional steam for industrial processes. This not only improves the economic efficiency of the power plant itself but may also provide heating services to surrounding communities, achieving cascaded energy utilization. After the heat from the waste gas is utilized, it forms low-temperature waste gas containing a certain amount of moisture. The wet, saturated flue gas in the waste gas rapidly cools and condenses into droplets during diffusion after being emitted into the atmosphere through a chimney, forming a white plume. In existing technologies, to eliminate this visual pollution, separate heating equipment is usually installed to heat the flue gas before emission. However, this not only fails to further improve the efficiency of the waste heat recovery boiler in utilizing the heat from the flue gas but also necessitates a separate heating unit to heat the flue gas to "eliminate the white plume."

[0004] In view of the above, it is necessary to propose a waste heat utilization boiler flue gas whitening system to solve the above problems. Utility Model Content

[0005] The purpose of this invention is to overcome the defects in the existing technology and provide a waste heat utilization boiler flue gas whitening system.

[0006] To achieve the above objectives, the technical solution of this utility model is as follows: A waste heat utilization boiler flue gas whitening system, comprising a first flue gas heat exchanger and a second flue gas heat exchanger installed on the exhaust flue, and a waste heat utilization chiller, wherein the waste heat utilization chiller includes an evaporator, a generator, a condenser, and an absorber; a first intermediate medium circulation for heat transfer is provided between the first flue gas heat exchanger and the evaporator; a second intermediate medium circulation for heat transfer is formed between the second flue gas heat exchanger and the waste heat utilization chiller; the second flue gas heat exchanger is located at the rear end of the first flue gas heat exchanger; the first flue gas heat exchanger cools the flue gas, and the second flue gas heat exchanger heats the flue gas.

[0007] Furthermore, the evaporator is provided with a first heat exchange pipeline, and the first flue gas heat exchanger is provided with a first water inlet and a first water return end. The first water inlet and the first water return end are respectively connected to the two ends of the first heat exchange pipeline through a circulation pipeline to form a loop.

[0008] Furthermore, a first medium circulation pump is provided on the first intermediate medium circulation.

[0009] Furthermore, the first flue gas heat exchanger has multiple heat exchange plates arranged in parallel at intervals. The surface of the heat exchange plates is provided with several fin structures. The fin structures are inclined at an angle to the horizontal plane with one end higher and the other end lower. The fin structures and the heat exchange plates form a V-shaped groove, so that the fin structures form an inclined guide groove for the condensate.

[0010] Furthermore, the V-shaped groove has an upward opening, allowing the fin structure to guide the condensate on the heat exchange plate to the inner wall of the exhaust flue; the lower edge of the heat exchange plate is provided with a horizontal guide groove.

[0011] Furthermore, the waste heat utilization chiller is provided with a second heat exchange pipeline, which passes through the absorber and the condenser in sequence. The second flue gas heat exchanger is provided with a second water inlet and a second water return. The second water inlet and the second water return are respectively connected to the two ends of the second heat exchange pipeline through a circulation pipeline to form a loop.

[0012] Furthermore, a second medium circulation pump is provided on the second intermediate medium circulation.

[0013] Furthermore, the horizontal guide channel collects condensate and flows into a collection tank, and an external pump is provided at the bottom of the collection tank.

[0014] Furthermore, the fin structures on two adjacent heat exchange plates are parallel and staggered.

[0015] Furthermore, the fin structures on two adjacent heat exchange plates are arranged in a cross pattern in space.

[0016] The advantages and beneficial effects of this utility model are as follows: This utility model's waste heat utilization boiler flue gas whitening system first cools the flue gas through a first flue gas heat exchanger, significantly reducing the water content in the flue gas; the flue gas then enters a second heat exchanger for heating, and the increased flue gas temperature achieves the purpose of whitening. This device utilizes the latent heat energy in the flue gas as the driving heat source for the waste heat chiller, effectively reducing energy consumption and achieving the purpose of whitening the flue gas. It is economical, practical, and has a good whitening effect. Furthermore, the finned structure of the heat exchange plate of the first flue gas heat exchanger can guide the condensate to the inner wall, forming a wall-adhering flow, which has a good condensate collection effect. The finned structure can also enhance the turbulence effect of the passing flue gas, effectively enhancing the heat exchange effect. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of a waste heat utilization boiler flue gas whitening system according to this utility model;

[0018] Figure 2 This is one of the structural schematic diagrams of the heat exchange plate in this utility model;

[0019] Figure 3 This is a schematic diagram of the longitudinal section of the heat exchange plate in this utility model;

[0020] Figure 4 This is the second schematic diagram of the heat exchange plate in this utility model;

[0021] In the diagram: 1. Exhaust flue; 2. First flue gas heat exchanger; 3. Second flue gas heat exchanger; 4. Waste heat recovery chiller; 5. Evaporator; 6. Generator; 7. Condenser; 8. Absorber; 9. First intermediate medium circulation; 10. Second intermediate medium circulation; 11. First heat exchange pipeline; 12. First water inlet; 13. First water return; 14. Circulation pipeline; 15. First medium circulation pump; 16. Heat exchange plate; 17. Fin structure; 18. V-groove; 19. Horizontal guide channel; 20. Second heat exchange pipeline; 21. Second water inlet; 22. Second water return; 23. Second medium circulation pump; 24. Collection tank; 25. External pump. Detailed Implementation

[0022] The specific embodiments of this utility model will be further described below with reference to the accompanying drawings and examples. The following examples are only used to more clearly illustrate the technical solution of this utility model and should not be construed as limiting the scope of protection of this utility model.

[0023] A waste heat recovery boiler flue gas whitening system includes a first flue gas heat exchanger 2 and a second flue gas heat exchanger 3 installed on an exhaust flue duct 1. The exhaust flue duct 1 can be the exhaust gas discharge pipe of a waste heat recovery boiler in a power plant. The flue gas temperature in this pipe is approximately 100 degrees Celsius, and it has a large amount of usable heat. To utilize this heat, the sensible heat in the flue gas can be recovered by directly exchanging heat between the heating network return water and the flue gas through the heat exchangers. However, due to the heating network return water temperature of 40-60 degrees Celsius and the temperature difference of the heat exchangers, the flue gas temperature drops from 100 degrees Celsius to approximately 50 degrees Celsius. This flue gas whitening system can further recover and utilize the latent heat in the flue gas at approximately 50 degrees Celsius. Specifically, as shown... Figure 1As shown, the system includes a waste heat recovery chiller 4, which comprises an evaporator 5, a generator 6, a condenser 7, and an absorber 8. A first intermediate medium circulation 9 for heat transfer is provided between the first flue gas heat exchanger 2 and the evaporator 5. A second intermediate medium circulation 10 for heat transfer is formed between the second flue gas heat exchanger 3 and the waste heat recovery chiller 4. The second flue gas heat exchanger 3 is located at the rear end of the first flue gas heat exchanger 2. The flue gas is cooled by the first flue gas heat exchanger 2. In actual control, the flue gas is cooled to 20-30 degrees Celsius after passing through the first flue gas heat exchanger 2, thereby removing the moisture contained in the flue gas. The system achieves separation through condensation, thereby significantly reducing the moisture content of the flue gas. After passing through the first flue gas heat exchanger 2, the moisture content of the flue gas is reduced to 10-15%. In order to avoid the formation of white smoke during the emission of flue gas and causing visual pollution, this system separates a loop from the waste heat utilization chiller 4, namely the second intermediate medium circulation 10. The second flue gas heat exchanger 3 is used to heat the emitted flue gas. A portion of the heat energy separated from the heat source end in the waste heat utilization chiller 4 is used to eliminate the white smoke in the flue gas. This achieves the purpose of utilizing part of the latent heat of the flue gas itself to eliminate the white smoke. In addition, the other latent heat of the flue gas can also be used for the return water heating and temperature increase circulation of the heating network.

[0024] Specifically, such as Figure 1 As shown, the evaporator 5 is equipped with a first heat exchange pipe 11, and the first flue gas heat exchanger 2 is equipped with a first water inlet 12 and a first water return 13. The first water inlet 12 and the first water return 13 are respectively connected to the two ends of the first heat exchange pipe 11 through a circulation pipe 14 to form a loop. In use, a first medium circulation pump 15 is provided on the first intermediate medium circulation 9. The water in the first intermediate medium circulation 9 pipe is circulated by the first medium circulation pump 15. The intermediate water exchanges heat with the flue gas in the first flue gas heat exchanger 2, absorbs the latent heat in the flue gas, and carries the heat into the evaporator 5 for utilization, forming a circulation to realize the utilization of the 50-degree latent heat of the flue gas.

[0025] Furthermore, after the flue gas passes through the first flue gas heat exchanger 2, the latent heat in the flue gas is absorbed and utilized, and the moisture in the flue gas is condensed, reducing the moisture content of the flue gas. To eliminate whitening during emission, a second flue gas heat exchanger 3 is installed at the rear end of the first flue gas heat exchanger 2. The waste heat utilization chiller 4 is equipped with a second heat exchange pipeline 20, such as... Figure 1 As shown, the second heat exchange pipeline 20 is the internal pipeline of the waste heat utilization chiller 4. The second heat exchange pipeline 20 passes through the absorber 8 and the condenser 7 in sequence, so that the intermediate water in the second intermediate medium circulation 10 is heated and sent to the second flue gas heat exchanger 3 through the second intermediate medium circulation 10 pipeline to exchange heat with the flue gas, so that the flue gas is heated to achieve whitening.

[0026] Specifically, the second flue gas heat exchanger 3 is provided with a second water inlet 21 and a second water return 22, which are respectively connected to the two ends of the second heat exchange pipeline 20 through the circulation pipeline 14 to form a loop. A second medium circulation pump 23 is provided on the second intermediate medium circulation 10. The second medium circulation pump 23 drives the intermediate water in the second intermediate medium circulation 10 pipeline to circulate.

[0027] Furthermore, the first flue gas heat exchanger 2 has multiple parallel and spaced heat exchange plates 16, and the surface of the heat exchange plates 16 is provided with several raised fin structures 17, such as... Figure 2 As shown, the fin structure 17 provided on the surface of the heat exchange plate 16 not only increases the heat exchange contact area of ​​the heat exchanger and improves the heat exchange effect, but also, the fin structure 17 is inclined at an angle to the horizontal plane with one end higher than the other, forming a V-shaped groove 18 between the fin structure 17 and the heat exchange plate 16, so that the fin structure 17 forms an inclined guide groove for the condensate; as Figure 2 As shown, the fin structure 17 with its inclined angle design allows the condensed liquid to flow down along the fin structure 17, and the lower end of the fin structure 17 is close to the inner wall of the exhaust flue 1, so that the condensed liquid forms a wall-attached falling effect, which is beneficial for the collection of condensed liquid.

[0028] Furthermore, the opening of the V-shaped groove 18 faces upward, allowing the fin structure 17 to guide the condensate on the heat exchange plate 16 to the inner wall of the exhaust flue 1; as... Figure 2 , 3 As shown, the lower edge of the heat exchange plate 16 is provided with a horizontal guide groove 19. Liquid condensed on the heat exchange plate 16 or fins falls along the wall or into the horizontal guide groove 19, facilitating collection of the condensate. The condensate is then connected to a collection tank 24 via a pipeline. Figure 1 As shown, the horizontal guide channel 19 collects condensate and flows into the collection tank 24, and the bottom of the collection tank 24 is equipped with an external pump 25.

[0029] As one embodiment of the fin structure 17, such as Figure 2 , 3 As shown, the fin structures 17 on adjacent heat exchange plates 16 are parallel. The heat exchange plates 16 of the first flue gas heat exchanger 2 have a double-plate structure, with a space between each pair of heat exchange plates 16 for intermediate water flow and an external space for flue gas flow, allowing heat exchange between flue gas and intermediate water through the heat exchange plates 16. Furthermore, the fin structures 17 on the heat exchange plates 16 on both sides are staggered. This arrangement, with the fin structures 17 between the heat exchange plates 16 staggered, increases the turbulence effect as the flue gas passes through.

[0030] As another embodiment of fin structure 17, such as Figure 4As shown, the fin structures 17 on two adjacent heat exchange plates 16 are arranged in a crisscross pattern in space. The solid and dashed lines in the figure respectively indicate the arrangement direction of the fin structures 17 on the two adjacent heat exchange plates 16, thereby allowing the condensate to flow evenly to both sides. This avoids the problem of reduced collection efficiency caused by the condensate flowing to the same side at the same time.

[0031] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present utility model, and these improvements and modifications should also be considered within the protection scope of the present utility model.

Claims

1. A waste heat recovery boiler flue gas desulfurization system, characterized in that, A first flue gas heat exchanger (2) and a second flue gas heat exchanger (3) are provided on the exhaust flue (1), and a waste heat utilization refrigerator (4) is also provided. The waste heat utilization refrigerator (4) includes an evaporator (5), a generator (6), a condenser (7), and an absorber (8). A first intermediate medium circulation (9) for heat transfer is provided between the first flue gas heat exchanger (2) and the evaporator (5), and a second intermediate medium circulation (10) for heat transfer is formed between the second flue gas heat exchanger (3) and the waste heat utilization refrigerator (4). The second flue gas heat exchanger (3) is located at the rear end of the first flue gas heat exchanger (2). The first flue gas heat exchanger (2) cools the flue gas, and the second flue gas heat exchanger (3) heats the flue gas.

2. The waste heat utilization boiler flue gas whitening system according to claim 1, characterized in that, The evaporator (5) is provided with a first heat exchange pipeline (11), and the first flue gas heat exchanger (2) is provided with a first water inlet (12) and a first water return (13). The first water inlet (12) and the first water return (13) are respectively connected to the two ends of the first heat exchange pipeline (11) through a circulation pipeline (14) to form a loop.

3. The waste heat utilization boiler flue gas whitening system according to claim 2, characterized in that, The first intermediate medium circulation (9) is equipped with a first medium circulation pump (15).

4. The waste heat utilization boiler flue gas whitening system according to claim 2, characterized in that, The first flue gas heat exchanger (2) has multiple parallel heat exchange plates (16) arranged at intervals. The surface of the heat exchange plate (16) is provided with several fin structures (17). The fin structures (17) are inclined at an angle to the horizontal plane with one end higher and the other end lower. The fin structures (17) and the heat exchange plate (16) form a V-shaped groove (18), so that the fin structures (17) form an inclined guide groove for the condensate.

5. A waste heat recovery boiler flue gas whitening system according to claim 4, characterized in that, The V-shaped groove (18) opens upward, allowing the fin structure (17) to guide the condensate on the heat exchange plate (16) to the inner wall of the exhaust flue (1); the lower edge of the heat exchange plate (16) is provided with a horizontal guide groove (19).

6. The waste heat utilization boiler flue gas whitening system according to claim 1, characterized in that, The waste heat utilization chiller (4) is provided with a second heat exchange pipeline (20), which passes through the absorber (8) and the condenser (7) in sequence. The second flue gas heat exchanger (3) is provided with a second water inlet (21) and a second water return (22). The second water inlet (21) and the second water return (22) are respectively connected to the two ends of the second heat exchange pipeline (20) through the circulation pipeline (14) to form a loop.

7. A waste heat recovery boiler flue gas whitening system according to claim 6, characterized in that, The second intermediate medium circulation (10) is equipped with a second medium circulation pump (23).

8. A waste heat recovery boiler flue gas whitening system according to claim 5, characterized in that, The horizontal guide channel (19) collects condensate and flows into the collection tank (24), and the bottom of the collection tank (24) is equipped with an external pump (25).

9. A waste heat recovery boiler flue gas whitening system according to claim 5, characterized in that, The fin structures (17) on two adjacent heat exchange plates (16) are parallel and staggered.

10. A waste heat recovery boiler flue gas whitening system according to claim 5, characterized in that, The fin structures (17) on two adjacent heat exchange plates (16) are arranged in a cross shape in space.

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