Device for reducing heat loss of power station boiler

Abstract

The utility model discloses a device for reducing heat loss of a power station boiler, which comprises a boiler, the boiler is connected with an air preheater, the boiler is provided with a drain input pipe communicated with a drain flash tank, and the drain flash tank is communicated with a recovery water tank; the recycling water tank is connected with a first heat exchange pipeline, a variable-frequency circulating water pump is mounted on the first heat exchange pipeline, the first heat exchange pipeline passes through a first heat exchanger, and the outlet end of the first heat exchange pipeline is communicated to a recycling water system; the air feeder is provided with an air supply pipe, the air supply pipe is connected to the air preheater, the air supply pipe passes through the first heat exchanger, and the first heat exchange pipeline exchanges heat with the air supply pipe in the first heat exchanger. The utility model solves the problem of low energy utilization rate caused by the fact that precious heat resources in drained water cannot be effectively recycled in the prior art.

Description

Technical Field

[0001] The utility model belongs to the technical field of thermal energy, and relates to a device for reducing heat loss of a power station boiler. Background Art

[0002] Currently, the fixed-discharge expansion tank and drain expansion tank systems widely used in power plant boiler operations generally discharge the drain water generated by boiler soot blowing, continuous blowdown, and periodic blowdown directly into the expansion tank. This traditional treatment method not only leads to the unnecessary loss of large amounts of water resources, but also involves significant heat loss, especially when the working fluid vaporizes at high temperatures, further exacerbating the severe energy waste. Furthermore, if the boiler exhaust temperature is set too high, far exceeding the flue gas dew point, it will inevitably lead to significant heat energy loss during the exhaust process, placing a heavy burden on the overall energy efficiency of the boiler system.

[0003] The limitations of traditional technologies are particularly evident in this area. The inability to effectively capture and recycle this valuable heat resource not only reduces the overall energy utilization efficiency but also indirectly affects the operating efficiency and long-term stability of various boiler system components, particularly the air preheater. As a crucial component of the boiler system, the performance of the air preheater is directly affected by the exhaust gas temperature and composition. Excessively high exhaust gas temperatures not only exacerbate the air preheater's ash blockage problem but can also reduce its heat exchange efficiency, thereby lowering the operating efficiency and economic efficiency of the entire boiler system. Utility Model Content

[0004] The purpose of the utility model is to provide a device for reducing heat loss of power station boilers, which solves the problem that traditional technologies fail to effectively recycle and utilize valuable heat resources in drain water, resulting in low energy utilization rate.

[0005] The technical solution adopted by the utility model is a device for reducing heat loss of a power station boiler, comprising a boiler, the boiler being connected to an air preheater, the boiler being provided with a drain input pipe connected to a drain expansion tank, the drain expansion tank being connected to a recovery water tank; the recovery water tank being connected to a first heat exchange pipe, the first heat exchange pipe being provided with a variable frequency circulating water pump, the first heat exchange pipe passing through a first heat exchanger, the outlet end of the first heat exchange pipe being connected to a recovery water system; the blower being provided with an air supply pipe, the air supply pipe being connected to the air preheater, the air supply pipe passing through the first heat exchanger, the first heat exchange pipe and the air supply pipe exchanging heat in the first heat exchanger.

[0006] The utility model is also characterized in that:

[0007] The air preheater is provided with an air outlet pipe, which is connected to the desulfurization tower and the chimney. The air outlet pipe passes through the electrostatic precipitator, the induced draft fan and the second heat exchanger in sequence; the first heat exchange pipe is connected to the inlet end of the second heat exchange pipe, and a control valve is provided on the first heat exchange pipe. The outlet end of the second heat exchange pipe is connected to the first heat exchange pipe after passing through the second heat exchanger, and the air outlet pipe and the second heat exchange pipe exchange heat in the second heat exchanger.

[0008] Furthermore, the recycled water system is provided with a circulation pipeline connected to the hydrophobic expansion tank.

[0009] Furthermore, the recovery water tank is provided with an overflow pipe.

[0010] Furthermore, the hydrophobic expansion tank includes a cylinder, a steam exhaust pipe is provided at the top of the cylinder, and the steam exhaust pipe is connected to the inside of the cylinder, a hydrophobic input pipe is provided at the top of the cylinder, a drain pipe is provided at the bottom of the cylinder, the drain pipe is connected to a recovery water tank, at least one cooling water pipe is provided in the cylinder, and a plurality of water spray pipes are provided on the cooling water pipe in the cylinder from bottom to top, the water spray pipes are connected to the cooling water pipe, at least one cooling air pipe is provided in the cylinder, and an air outlet is provided on the outer wall of the cooling air pipe.

[0011] Furthermore, the cooling air pipe is a spiral pipe.

[0012] Furthermore, each cooling air pipe is surrounded by a cooling water pipe in the vertical direction, and the number of the cooling air pipes is the same as the number of the cooling water pipes.

[0013] Furthermore, a shower head is provided on the outer wall of the hydrophobic inlet pipe extending into the cylinder, and water spray holes are evenly opened on the outer wall of the water spray pipe.

[0014] Furthermore, the water spray pipe is circumferentially connected to a plurality of fan blades, the surfaces of the fan blades are perpendicular to the water outlet direction of the shower head, and the plurality of fan blades rotate circumferentially around the water spray pipe.

[0015] Furthermore, the exhaust pipe is provided with a first temperature control valve.

[0016] The beneficial effects of the utility model are:

[0017] 1. In this utility model, a drain pipe connects to a drain expansion tank in the boiler, which recovers the large amount of hot water generated during boiler startup. This design not only cleverly recovers the large amount of heat contained in the drain during boiler startup, achieving energy recycling, but also significantly reduces unnecessary waste of working fluid and significantly reduces water consumption during boiler operation. Furthermore, by increasing the air temperature at the air preheater inlet, the overall temperature environment at the cold end is further optimized, laying a solid foundation for the efficient and stable operation of the boiler system.

[0018] 2. The utility model sets a control valve in the second heat exchange pipe to control the circulating water volume of the heat exchanger at the outlet of the induced draft fan, so as to achieve the purpose of controlling the temperature of the flue gas in the second heat exchanger, preventing the flue gas temperature at the outlet of the induced draft fan from dropping below the flue gas dew point. By maintaining the flue gas temperature always above the flue gas dew point, the leakage problem caused by low-temperature corrosion of the heat exchanger is effectively prevented, and the reliability and stability of the boiler system are further improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0020] Figure 1 It is a structural diagram of the utility model;

[0021] Figure 2 It is a structural schematic diagram of the hydrophobic expansion container of the utility model;

[0022] Figure 3 This is a top sectional view of the hydrophobic expansion container of the present utility model;

[0023] In the figure, 1. Boiler, 2. Drain expansion tank, 3. Blower, 4. Electrostatic precipitator, 5. Induced draft fan, 6-1. First heat exchanger, 6-2. Second heat exchanger, 7. Recovery water tank, 8. Variable frequency circulating water pump, 9. Desulfurization tower, 10. Chimney, 11. Control valve, 12. Air preheater, 13. Recovery water system, 2-1. Cylinder, 2-2. Exhaust pipe, 2-3. Drain inlet pipe, 2-4. Drain pipe, 2-5. Cooling water pipe, 2-6. Spray pipe, 2-7. Shower head, 2-8. Fan blades, 2-9. Cooling air pipe. DETAILED DESCRIPTION

[0024] The following is a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0025] The following is combined with Figure 1 To the attached Figure 3 And specific embodiments, the utility model is discussed in detail:

[0026] Example 1

[0027] A device for reducing heat loss in power station boilers, such as Figure 1 As shown, it includes a boiler 1, which is connected to an air preheater 12. The boiler 1 is provided with a drain inlet pipe 2-3 connected to the drain expansion tank 2, and the drain expansion tank 13 is connected to the recovery water tank 2; the recovery water tank 2 is provided with a first heat exchange pipe, and a variable frequency circulating water pump 8 is installed on the first heat exchange pipe. The first heat exchange pipe passes through the first heat exchanger 6-1, and the outlet end of the first heat exchange pipe is connected to the recovery water system 13; the blower 3 is provided with an air supply pipe connected to the air preheater 12, and the air supply pipe passes through the first heat exchanger 6-1. The first heat exchange pipe and the air supply pipe exchange heat in the first heat exchanger 6-1.

[0028] Furthermore, the air preheater 12 is equipped with an outlet duct, which is connected to the desulfurization tower 9 and the chimney 10. The outlet duct passes through the electrostatic precipitator 4, the induced draft fan 5, and the second heat exchanger 6-2 in sequence. The first heat exchange pipe is connected to the inlet of the second heat exchange pipe. The first heat exchange pipe is equipped with a control valve 11. The outlet of the second heat exchange pipe passes through the second heat exchanger 6-2 and then connects to the first heat exchange pipe. The outlet duct and the second heat exchange pipe exchange heat within the second heat exchanger 6-2. To prevent the flue gas temperature at the outlet of the induced draft fan 5 from dropping below the flue gas dew point, causing corrosion and leakage in the second heat exchanger 6-2, the control valve 11 is used to control the circulating water volume of the second heat exchanger 6-2 to achieve the purpose of controlling the flue gas temperature while not affecting the recovery of the hydrophobic heat and working fluid in the hydrophobic expansion tank 2.

[0029] Furthermore, the recycled water system 13 is provided with a circulation pipe connected to the hydrophobic expansion tank 2, and the water with lower temperature in the recycled water system 13 is then connected to the hydrophobic expansion tank and used as cooling water for circulation.

[0030] Furthermore, the recovery water tank 7 is provided with an overflow pipe, which controls the water output in the recovery water tank 7 to be within a reasonable range, and overflows through the overflow pipe 7 when necessary.

[0031] Further, such as Figure 2 、 3 As shown, it includes a cylinder 2-1, a steam exhaust pipe 2-2 is provided on the top of the cylinder 2-1 and the steam exhaust pipe 2-2 is connected to the inside of the cylinder 2-1, a drain input pipe 2-3 is provided on the top of the cylinder 2-1, a drain pipe 2-4 is provided at the bottom of the cylinder 2-1, the drain pipe 2-4 is connected to the recovery water tank 7, one or more cooling water pipes 2-5 are provided in the cylinder 2-1, and a plurality of water spray pipes 2-6 are provided on the cooling water pipe 2-5 in the cylinder 2-1 from bottom to top, and the water spray pipe 2-6 is connected to the cooling water pipe 2-5, one or more cooling air pipes 2-9 are provided in the cylinder 2-1, and an air outlet is opened on the outer wall of the cooling air pipe 2-9.

[0032] Furthermore, the cooling air pipe 2-9 is a spiral pipe. Compared with a straight pipe, the spiral pipe has a larger air supply area at the same height.

[0033] Furthermore, each cooling air pipe 2-9 vertically surrounds a cooling water pipe 2-5, and the number of cooling air pipes 2-9 is the same as the number of cooling water pipes 2-5. The cooling air pipes 2-9 spray cold air from all sides of the cooling water pipe 2-5, and the cold air exchanges heat with the hydrophobic water sprayed by the water spray pipe 2-6.

[0034] Furthermore, a showerhead 2-7 is provided on the outer wall of the drain inlet pipe 2-3, which extends into the interior of the cylinder. Water spray holes are evenly distributed on the outer wall of the water spray pipe 2-6. The showerhead 2-7 sprays drain downward, while the water spray pipe 2-6 sprays desuperheated water from the spray holes. As the drain falls, it exchanges heat with the air, and the desuperheated water exchanges heat with the air. The air acts as the medium for the initial heat exchange between the two. Then, the two waters fall to the bottom of the cylinder 2-1 and meet for a secondary heat exchange. The hot air is then discharged through the exhaust pipe 2-2 at the top of the cylinder, and replaced by fresh cold air for a new heat exchange, repeating the cycle.

[0035] Furthermore, the water spray pipe 2-6 is circumferentially connected to a plurality of blades 2-8, the blade surfaces of the blades 2-8 being perpendicular to the direction of water discharge from the shower head 2-7, and the plurality of blades 2-8 rotating circumferentially around the water spray pipe 2-6. The shower head 2-7 sprays the hydrophobic water downward, and the hydrophobic water falls on the blades 2-8. The blades 2-8 are pushed by the gravity of the hydrophobic water and rotate circumferentially around the water spray pipe 2-6, forming an airflow within the cylinder 2-1. The airflow accelerates the heat exchange between the hydrophobic water and the air during its fall. The hydrophobic expansion container 2 utilizes the shower head 2-7 and the water spray pipe 2-6 for multiple heat exchanges, effectively improving the heat recovery efficiency. At the same time, the design of the circumferentially movable blades 2-8 of the water spray pipe 2-6 enhances the heat exchange effect and accelerates the heat exchange process during the fall of the hydrophobic water.

[0036] Furthermore, the exhaust pipe 2-2 is provided with a first temperature control valve. When the temperature of the cylinder 2-1 exceeds the temperature set by the first temperature control valve, the first temperature control valve opens to allow the exhaust pipe 2-2 to discharge the hot air from the cylinder 2-1.

[0037] The utility model is a device for reducing heat loss of a power station boiler. Its working principle is as follows: when the boiler 1 is started, a large amount of hot water is generated. The large amount of hot water is discharged into the drain expansion tank 2 along the drain inlet pipe 2-3. The drain expansion tank 2 conveys the hot water to the recovery water tank 2. The variable frequency circulating water pump 8 conveys the hot water to the first heat exchanger 6-1. The gas at the outlet of the air supply pipe of the blower 3 exchanges heat with the hot water. After the heat exchange, the air enters the inlet of the air preheater 12. The waste water after the heat exchange is recovered to the recovery water system 13 along the first heat exchange pipe.

[0038] During operation, drain water is generated and collected into the drain expansion tank 2 through the drain inlet pipe 2-3. Desuperheated water is sprayed into the drain expansion tank 2 to liquefy the high-temperature steam into water. The drain expansion tank 2 transports the high-temperature drain water to the recovery water tank 2. The variable frequency circulating water pump 8 transports the high-temperature drain water to the first heat exchanger 6-1. The gas at the outlet of the air supply pipe of the blower 3 exchanges heat with the high-temperature drain water. After the heat exchange, the air enters the inlet of the air preheater 12. The waste water after the heat exchange is recovered along the first heat exchange pipe to the water collection system 13.

[0039] A portion of the drain is diverted from the first heat exchange pipe into the second heat exchange pipe, and then pumped into the second heat exchanger 6-2 through the variable frequency circulating water pump 8, so that this portion of the drain is exchanged with the flue gas at the outlet of the induced draft fan 5. After heat exchange, new high-temperature drain is generated, and the new high-temperature drain flows back to the first heat exchange pipe. The variable frequency circulating water pump 8 sends the new high-temperature drain to the first heat exchanger 6-1, and the gas at the outlet of the air supply pipe of the blower 3 exchanges heat with the high-temperature drain to increase the secondary air temperature at the inlet of the air preheater.

[0040] Drain generated by boiler 1 enters cylinder 2-1 through drain inlet pipe 2-3. A showerhead 2-7 is located on the outer wall of drain inlet pipe 2-3. As drain passes through showerhead 2-7, it is evenly sprayed into cylinder 2-1. During this process, the drain begins a preliminary heat exchange with the air inside cylinder 2-1.

[0041] Inside the cylinder 2-1, one or more cooling water pipes 2-5 are installed. Multiple spray pipes 2-6 are mounted on these pipes 2-5 from bottom to top. The outer walls of the spray pipes 2-6 are uniformly perforated with spray holes for spraying cooling water. As the hydrophobic water from the showerhead 2-7 falls, the cooling water is simultaneously sprayed out from the spray pipes 2-6. The cooling water and the hydrophobic water mix within the cylinder 1 and continue to fall to the bottom of the cylinder 2-1, draining along the pipes into the water collection tank 7. During this process, the cooling water exchanges heat with the hydrophobic water and the surrounding air, further reducing the hydrophobic water temperature.

[0042] The hydrophobic water sprayed by the showerhead 2-7 at a high position falls downwards and drips onto the fan blades 2-8. The fan blades 2-8 are then acted upon by the force generated by the hydrophobic water sliding on the fan blades 2-8, causing them to rotate circumferentially around the water spray pipe 2-6. The rotation of the fan blades creates an airflow within the cylinder 2-1. This airflow not only accelerates the flow of air as the hydrophobic water falls, but also enhances the heat exchange effect, making the heat exchange between the hydrophobic water and the cooling water more efficient.

[0043] The fan draws cool air from the outside into cooling air duct 2-9. This cool air is ejected through the outlet holes on the outer wall of cooling air duct 2-9, exchanging heat with the hydrophobic and attenuated water sprayed from water spray pipe 2-6, further reducing its temperature. The spiral duct design increases the air delivery area at the same height, improving cooling efficiency.

[0044] When the temperature inside the cylinder 1 exceeds the temperature set by the first temperature control valve, the temperature control valve automatically opens, allowing hot gas to be discharged through the exhaust pipe 2-2 to maintain the temperature inside the cylinder 2-1 within a safe range.

[0045] As the drain and cooling water continuously fall and exchange heat within cylinder 2-1, the heat is gradually absorbed by the air and the cooling water in cooling water pipe 2-5. Once the hot air is discharged through exhaust pipe 2-2, the fan continues to pump new cold air into cylinder 2-1, beginning a new heat exchange cycle. This ensures continuous heat recovery and cooling water conservation throughout the system.

[0046] The advantages of the device for reducing heat loss of power station boilers of the utility model are:

[0047] This device recovers a significant amount of heat from the boiler's draining process, achieving energy recycling and significant reduction in heat loss during flue gas exhaust, thereby improving the boiler's overall operating efficiency. The device's recovery water tank cools and recycles the drained water, significantly reducing unnecessary waste of working fluids (such as water and steam) and significantly reducing water consumption during boiler operation.

[0048] By using the recovered heat to preheat the cold air entering the air preheater, the inlet air temperature of the air preheater is increased, the comprehensive temperature environment at the cold end is optimized, which is conducive to the stable operation of the air preheater and reduces ash blockage. The flue gas flow path and temperature control strategy are optimized, the operating energy consumption of the fan is reduced, and the equipment wear caused by high temperature and ash blockage is reduced, thereby extending the service life of the equipment.

[0049] The device design focuses on preventing direct wear and tear on the heat exchanger from dust in the flue gas, thus avoiding the risk of leakage caused by wear. It also ensures that the flue gas temperature is always maintained above the flue gas dew point, effectively preventing leakage caused by low-temperature corrosion in the heat exchanger. These multiple optimization measures have improved the overall reliability and stability of the boiler system, reducing downtime and maintenance costs caused by equipment failure.

[0050] The above further describes the present invention with the help of specific embodiments, but it should be understood that the specific description here should not be construed as limiting the essence and scope of the present invention. Various modifications made to the above embodiments by ordinary technicians in this field after reading this specification are all within the scope of protection of the present invention.

Claims

1. A device for reducing heat loss of a power station boiler, characterized in that: The invention comprises a boiler (1), wherein the boiler (1) is connected to an air preheater (12), the boiler (1) is provided with a drain inlet pipe (2-3) connected to a drain expansion tank (2), and the drain expansion tank (2) is connected to a recovery water tank (7); the recovery water tank (7) is connected to a first heat exchange pipe, a variable frequency circulating water pump (8) is installed on the first heat exchange pipe, the first heat exchange pipe passes through a first heat exchanger (6-1), and the outlet end of the first heat exchange pipe is connected to a recovery water system (13); the blower (3) is provided with an air supply pipe, the air supply pipe is connected to the air preheater (12), the air supply pipe passes through the first heat exchanger (6-1), and the first heat exchange pipe and the air supply pipe exchange heat in the first heat exchanger (6-1).

2. The device for reducing heat loss of a power plant boiler according to claim 1, characterized in that: The air preheater (12) is provided with an air outlet pipe, which is connected to the desulfurization tower (9) and the chimney (10), and the air outlet pipe passes through the electrostatic precipitator (4), the induced draft fan (5) and the second heat exchanger (6-2) in sequence; the first heat exchange pipe is connected to the inlet end of the second heat exchange pipe, and the first heat exchange pipe is provided with a control valve (11). The outlet end of the second heat exchange pipe passes through the second heat exchanger (6-2) and is connected to the first heat exchange pipe, and the air outlet pipe and the second heat exchange pipe exchange heat in the second heat exchanger (6-2).

3. The device for reducing heat loss of a power plant boiler according to claim 1, characterized in that: The water recovery system (13) is provided with a circulation pipeline connected to the hydrophobic expansion tank (2).

4. The device for reducing heat loss of a power plant boiler according to claim 1, characterized in that: The recovery water tank (7) is provided with an overflow pipe.

5. The device for reducing heat loss of a power plant boiler according to claim 1, characterized in that: The hydrophobic expansion tank (2) comprises a cylinder (2-1), a steam exhaust pipe (2-2) is provided at the top of the cylinder (2-1), and the steam exhaust pipe (2-2) is communicated with the inside of the cylinder (2-1), a hydrophobic inlet pipe (2-3) is provided at the top of the cylinder (2-1), a drainage pipe (2-4) is provided at the bottom of the cylinder (2-1), and the drainage pipe (2-4) is communicated with a recovery water tank (7), at least one cooling water pipe (2-5) is provided in the cylinder (2-1), and a plurality of water spray pipes (2-6) are provided from bottom to top on the cooling water pipe (2-5) in the cylinder (2-1), and the water spray pipes (2-6) are communicated with the cooling water pipe (2-5), at least one cooling air pipe (2-9) is provided in the cylinder (2-1), and an air outlet is provided on the outer wall of the cooling air pipe (2-9).

6. The device for reducing heat loss of a power plant boiler according to claim 5, characterized in that: The cooling air pipe (2-9) is a spiral pipe.

7. The device for reducing heat loss of a power plant boiler according to claim 6, characterized in that: Each of the cooling air pipes (2-9) vertically surrounds one of the cooling water pipes (2-5), and the number of the cooling air pipes (2-9) is the same as the number of the cooling water pipes (2-5).

8. The device for reducing heat loss of a power plant boiler according to claim 5, characterized in that: The outer wall of the drainage inlet pipe (2-3) extending into the cylinder is provided with a shower head (2-7), and the outer wall of the water spray pipe (2-6) is evenly provided with water spray holes.

9. The device for reducing heat loss of a power plant boiler according to claim 8, characterized in that: The water spray pipe (2-6) is circumferentially connected to a plurality of fan blades (2-8), the surfaces of the fan blades (2-8) are perpendicular to the water outlet direction of the shower head (2-7), and the plurality of fan blades (2-8) rotate circumferentially around the water spray pipe (2-6).

10. The device for reducing heat loss of a power plant boiler according to claim 5, characterized in that: The exhaust pipe (2-2) is provided with a first temperature control valve.

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