Flue gas auxiliary heating device of coal-fired thermal power generating unit

Abstract

The utility model discloses a coal-fired thermal power generating unit flue gas auxiliary heating device which is arranged between an outlet of a coal economizer and an inlet of an SCR denitration reactor and comprises a horizontal flue and a bypass flue which are arranged in parallel, a flue gas electric heater is arranged in the bypass flue and connected with an external power source, and the external power source is connected with the horizontal flue and the bypass flue. Smoke temperature measuring points are arranged on the upstream portions and the downstream portions of the horizontal flue and the bypass flue, and opening and closing valves are arranged on the horizontal flue and the bypass flue. According to the flue gas heating device, the bypass flue is connected to the horizontal flue in parallel, and the flue gas electric heater is arranged on the bypass flue, so that flue gas which does not meet the lower limit value of operation of the denitration system can be heated, and the horizontal flue or the bypass flue can be controlled to be conducted through the opening and closing valve; and when the flue gas meets the lower limit value of the operation of the denitration system, the bypass flue is closed, so that the temperature of the flue gas reaches the lower limit value of the operation of the denitration system.

Description

Technical Field

[0001] The utility model relates to the technical field of electric power equipment, and more specifically to a smoke auxiliary heating device for a coal-fired thermal power unit. Background Art

[0002] In recent years, during the clean and low-carbon transformation of the power industry, clean energy such as wind power and photovoltaic power generation has been connected to the grid on a large scale. Due to the volatility, intermittency and randomness of wind and light energy, the power grid urgently needs full-load peak regulation of coal-fired power units. Improving the flexibility of deep peak regulation of coal-fired power units has become an urgent task in building a new power system. In the stage when wind, light and other power generation resources are abundant, it is required that coal-fired power units are in low-load deep peak regulation operation. The flue gas temperature entering the denitrification system drops sharply, reaching the lower limit of exiting the denitrification system operation, so that the power plant boiler emission indicators cannot meet the national industry emission requirements. The sudden drop in the flue gas temperature entering the denitrification system limits the low-load deep flexible peak regulation performance of coal-fired power units.

[0003] See also Figure 1 The current coal-fired thermal power unit denitration system includes a boiler 1 and an SCR denitration reactor 5. The boiler 1 is connected to the SCR denitration reactor 5 through a pipeline. The flue gas 2 flows in the pipeline. An economizer 3 is arranged in the pipeline, and a flue gas temperature measuring point 4 is set between the economizer 3 and the SCR denitration reactor 5.

[0004] When the flue gas 2 temperature detected by the flue gas temperature measuring point 4 is lower than the lower limit of the denitration system operation, the SCR denitration reactor 5 will not be able to operate normally, so that the nitrogen oxide emission index in the flue gas of the power plant cannot meet the national industry emission requirements. Utility Model Content

[0005] The technical problem to be solved by the utility model is how to ensure that the flue gas temperature reaches the lower limit value of the operation of the denitration system.

[0006] The utility model solves the above technical problems through the following technical means: a flue gas auxiliary heating device for a coal-fired thermal power unit is arranged between the economizer outlet and the SCR denitrification reactor inlet, comprising a horizontal flue and a bypass flue arranged in parallel, a flue gas electric heater is arranged in the bypass flue, and the flue gas electric heater is connected to an external power supply, flue gas temperature measuring points are arranged upstream and downstream of the horizontal flue and the bypass flue, and opening and closing valves are arranged on the horizontal flue and the bypass flue.

[0007] By connecting a bypass flue in parallel to the horizontal flue and installing a flue gas electric heater on the bypass flue, the flue gas that does not meet the lower limit of the operation of the denitrification system can be heated. By setting the opening and closing valves, the conduction of the horizontal flue or the bypass flue can be controlled. When the flue gas meets the lower limit of the operation of the denitrification system, the bypass flue is closed to ensure that the flue gas temperature reaches the lower limit of the operation of the denitrification system.

[0008] As a preferred technical solution, an opening and closing valve is provided on the horizontal flue, and the opening and closing valve includes a baffle 1 and a driving motor. The output end of the driving motor is transmission-connected to the baffle 1, and the output end of the driving motor can drive the baffle 1 to rotate with its axis as the rotating shaft and cause the horizontal flue to be opened or closed.

[0009] As a preferred technical solution, the opening and closing valve includes an electric shutter.

[0010] As a preferred technical solution, the opening and closing valve includes a baffle 1 and an electric telescopic rod. The electric telescopic rod is fixedly connected to the outside of the horizontal flue, and the telescopic end of the electric telescopic rod is fixedly connected to the baffle 1. The electric telescopic rod can drive the baffle 1 to extend into or out of the conveying surface of the horizontal flue and cause the horizontal flue to be opened or closed.

[0011] As a preferred technical solution, both the input end and the output end of the bypass flue are provided with an opening and closing valve, and the opening and closing valve of the bypass flue has the same structure as the opening and closing valve on the horizontal flue.

[0012] As a preferred technical solution, the external power supply includes an in-plant busbar, and the in-plant busbar is electrically connected to the flue gas electric heater.

[0013] As a preferred technical solution, the external power source includes a photovoltaic power station and an energy storage battery group, and the flue gas electric heater is electrically connected to the photovoltaic power station through the energy storage battery group.

[0014] As an optimal technical solution, the smoke temperature measuring points include smoke temperature measuring point one and smoke temperature measuring point two. The smoke temperature measuring point one is located upstream of the horizontal flue and the bypass flue, and the smoke temperature measuring point two is located downstream of the horizontal flue and the bypass flue.

[0015] As a preferred technical solution, the baffle 1 is located in the middle of the horizontal flue.

[0016] As a preferred technical solution, the cross-section of the horizontal flue is circular, and the baffle 1 is a disc that matches the horizontal flue.

[0017] The advantages of the utility model are:

[0018] (1) In the utility model, a bypass flue is connected in parallel to the horizontal flue and a flue gas electric heater is provided on the bypass flue, so that the flue gas that does not meet the lower limit value of the operation of the denitrification system can be heated. By setting the opening and closing valve, the conduction of the horizontal flue or the bypass flue can be controlled. When the flue gas meets the lower limit value of the operation of the denitrification system, the bypass flue is closed to ensure that the flue gas temperature reaches the lower limit value of the operation of the denitrification system.

[0019] (2) In the utility model, by connecting the flue gas electric heater to the on-site bus and the photovoltaic power station, one is used and the other is reserved. When the coal-fired power unit is at low load for a long time, causing the flue gas electric heater to continue to work and the energy storage battery pack is exhausted, the power supply of the flue gas electric heater can be switched to the 6KV bus in the factory, and the 6KV bus is used to supply power, thereby improving the stability of the auxiliary heating device. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A schematic diagram of the out-of-stock system structure provided as the background technology of the utility model;

[0021] Figure 2 A schematic diagram of the structure of a flue gas auxiliary heating device provided in an embodiment of the utility model;

[0022] Figure numbers: 1. Boiler; 2. Flue gas; 3. Economizer; 4. Flue gas temperature measuring point; 5. SCR denitrification reactor; 6. Flue gas temperature measuring point one; 7. Flue gas temperature measuring point two; 8. Baffle one; 9. Baffle two; 10. Baffle three; 11. Horizontal flue; 12. Bypass flue; 13. Flue gas electric heater; 14. Busbar within the plant; 15. Energy storage battery pack; 16. Photovoltaic power station. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solution and advantages of the embodiments of the utility model clearer, the technical solution in the embodiments of the utility model will be clearly and completely described below in combination with the embodiments of the utility model. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0024] See also Figure 2 A flue gas auxiliary heating device for a coal-fired thermal power unit is arranged between the outlet of an economizer 3 and the inlet of an SCR denitrification reactor 5, comprising a horizontal flue 11 and a bypass flue 12 arranged in parallel, a flue gas electric heater 13 is arranged in the bypass flue 12, and the flue gas electric heater 13 is connected to an external power supply. An opening and closing valve is arranged on both the horizontal flue 11 and the bypass flue 12. By connecting a bypass flue 12 in parallel to the original horizontal flue 11 and arranging the flue gas electric heater 13 on the bypass flue 12, the flue gas 2 that does not meet the lower limit value of the operation of the denitrification system can be heated. By setting the opening and closing valve, the horizontal flue 11 or the bypass flue 12 can be controlled to be conductive. When the flue gas 2 meets the lower limit value of the operation of the denitrification system, the bypass flue 12 is closed to ensure that the temperature of the flue gas 2 reaches the lower limit value of the operation of the denitrification system.

[0025] Flue gas temperature measuring points 4 are provided upstream and downstream of the horizontal flue 11 and the bypass flue 12. The flue gas temperature measuring points 4 include a flue temperature measuring point 1 6 and a flue temperature measuring point 2 7. The flue temperature measuring point 1 6 is located upstream of the horizontal flue 11 and the bypass flue 12, and the flue temperature measuring point 2 7 is located downstream of the horizontal flue 11 and the bypass flue 12. The temperature of the flue gas 2 passing through the economizer 3 can be detected through the flue temperature measuring point 1 6. When the temperature of the flue gas 2 is lower than the lower limit value of the operation of the denitrification system, the horizontal flue 11 is closed, the bypass flue 12 is opened, and the flue gas 2 is heated by the flue gas electric heater 13 to reach the lower limit value of the operation of the denitrification system; when the flue gas 2 meets the lower limit value of the operation of the denitrification system, the bypass flue is closed to ensure that the temperature of the flue gas 2 reaches the lower limit value of the operation of the denitrification system.

[0026] See also Figure 2 The horizontal flue 11 is provided with an opening and closing valve, and the bypass flue 12 is provided with two opening and closing valves, wherein the horizontal flue 11 is provided with a baffle 8 and a driving motor, and the baffle 8 and the driving motor can form an opening and closing valve, the baffle 8 is located in the middle of the horizontal flue 11, and the output end of the driving motor is connected to the baffle 8 by transmission, and the output end of the driving motor can drive the baffle 8 to rotate with its axis as the rotating shaft and cause the horizontal flue 11 to be turned on or off, the cross section of the horizontal flue 11 is circular, and the baffle 8 is a disc adapted to the horizontal flue 11;

[0027] The opening and closing valve can be a baffle 8 and an electric telescopic rod, the electric telescopic rod is fixedly connected to the outside of the horizontal flue, the telescopic end of the electric telescopic rod is fixedly connected to the baffle 8, and the electric telescopic rod can drive the baffle 8 to extend into or out of the conveying surface of the horizontal flue 11 and cause the horizontal flue 11 to be turned on or off;

[0028] Of course, the opening and closing valve can also be a butterfly valve, a ball valve, a gate valve, an electric shutter, etc. in the prior art, but is not limited thereto;

[0029] It should be noted that the two opening and closing valves on the bypass flue 12 have the same structure as the opening and closing valves of the horizontal flue 11. In this embodiment, a baffle 2 9 is provided at the input end of the bypass flue 12, and a baffle 3 10 is provided at the output end. Both the baffle 2 9 and the baffle 3 10 can be driven by the above-mentioned driving motor or electric telescopic rod to control the bypass flue 12 to be turned on or off, or directly set as an electric blind in the prior art;

[0030] The external power supply in this embodiment can be the in-plant bus 14, which is electrically connected to the flue gas electric heater 13, or it can be the photovoltaic power station 16 and the energy storage battery group 15. The flue gas electric heater 13 is electrically connected to the photovoltaic power station 16 through the energy storage battery group 15, or it can be connected to the in-plant bus 14 and the photovoltaic power station 16 and the energy storage battery group 15 at the same time, so that one is used and the other is reserved. When the coal-fired power unit is at low load for a long time, causing the flue gas electric heater 13 to continue to work and the energy storage battery group 15 is exhausted, the power supply of the flue gas electric heater 13 can be switched to the 6KV in-plant bus 14, and the 6KV in-plant bus 14 is used for power supply, thereby improving the stability of the auxiliary heating device.

[0031] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A flue gas auxiliary heating device for a coal-fired power plant, arranged between the outlet of an economizer (3) and the inlet of an SCR denitrification reactor (5), characterized in that: The invention comprises a horizontal flue (11) and a bypass flue (12) which are arranged in parallel, wherein a flue gas electric heater (13) is arranged in the bypass flue (12), and the flue gas electric heater (13) is connected to an external power supply, and flue gas temperature measuring points (4) are arranged upstream and downstream of the horizontal flue (11) and the bypass flue (12), and opening and closing valves are arranged on the horizontal flue (11) and the bypass flue (12).

2. A flue gas auxiliary heating device for a coal-fired power plant according to claim 1, characterized in that: The horizontal flue (11) is provided with an opening and closing valve, which includes a baffle plate (8) and a drive motor. The output end of the drive motor is in transmission connection with the baffle plate (8). The output end of the drive motor can drive the baffle plate (8) to rotate with its axis as a rotating shaft and cause the horizontal flue (11) to be opened or closed.

3. The flue gas auxiliary heating device for coal-fired power generation unit according to claim 1, characterized in that: The opening and closing valve includes an electric shutter.

4. The flue gas auxiliary heating device for a coal-fired power plant according to claim 1, characterized in that: The opening and closing valve comprises a baffle plate (8) and an electric telescopic rod, wherein the electric telescopic rod is fixedly connected to the outside of the horizontal flue, and the telescopic end of the electric telescopic rod is fixedly connected to the baffle plate (8). The electric telescopic rod can drive the baffle plate (8) to extend into or out of the conveying surface of the horizontal flue (11) and cause the horizontal flue (11) to be opened or closed.

5. A flue gas auxiliary heating device for a coal-fired power plant according to any one of claims 2 to 4, characterized in that: The input end and the output end of the bypass flue (12) are both provided with an opening and closing valve, and the opening and closing valve of the bypass flue (12) has the same structure as the opening and closing valve on the horizontal flue (11).

6. The flue gas auxiliary heating device for coal-fired power generation unit according to claim 1, characterized in that: The external power supply comprises an in-plant busbar (14), and the in-plant busbar (14) is electrically connected to the flue gas electric heater (13).

7. The flue gas auxiliary heating device for coal-fired power generation unit according to claim 1, characterized in that: The external power source comprises a photovoltaic power station (16) and an energy storage battery group (15), and the flue gas electric heater (13) is electrically connected to the photovoltaic power station (16) via the energy storage battery group (15).

8. The flue gas auxiliary heating device for coal-fired power generation unit according to claim 1, characterized in that: The smoke temperature measuring point (4) comprises a smoke temperature measuring point one (6) and a smoke temperature measuring point two (7), wherein the smoke temperature measuring point one (6) is located upstream of the horizontal flue (11) and the bypass flue (12), and the smoke temperature measuring point two (7) is located downstream of the smoke temperature measuring point one (6) and the horizontal flue (11) and the bypass flue (12).

9. A flue gas auxiliary heating device for a coal-fired power plant according to claim 2 or 4, characterized in that: The baffle plate 1 (8) is located in the middle of the horizontal flue (11).

10. The flue gas auxiliary heating device for coal-fired power generation unit according to claim 2, characterized in that: The cross section of the horizontal flue (11) is circular, and the baffle plate 1 (8) is a disc that matches the horizontal flue (11).

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