Thermal power generating unit main steam supply shaft seal temperature reduction device
By designing a desuperheating device for the main steam supply shaft seal of a thermal power unit, and utilizing components such as a steam desuperheating station and sensor controller, the problem of inconsistent main steam temperature and metal temperature on the upper wall of the regulating stage cylinder was solved, thus achieving precise temperature control and ensuring the reliability of the unit.
Patent Information
- Application Number
- CN202520099798.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-16
- Publication Date
- 2025-12-09
- Estimated Expiration
- 2035-01-16
AI Technical Summary
Existing technologies make it difficult to precisely control the consistency between the main steam temperature and the metal temperature of the upper wall inside the regulating stage cylinder, resulting in the shaft seal steam temperature and the metal temperature of the upper wall inside the regulating stage cylinder being inconsistent, which affects the reliability of the unit.
Design a main steam supply shaft seal desuperheating device for thermal power units, including a steam desuperheating station, a main steam pressure regulating valve, an overpressure safety valve, a manual shut-off valve, a check valve, and an auxiliary steam pressure regulating station. These components regulate the main steam temperature to ensure it matches the high-pressure shaft seal temperature. Steam flow, pressure, and temperature sensors and controllers are installed to achieve automatic adjustment and alarm functions.
It achieves the control of the temperature deviation between the main steam supply shaft seal and the high-pressure shaft seal within 50℃, reduces the impact of temperature difference on bearing vibration, ensures the reliability of the unit, and enables self-steam supply through main steam desuperheating in the absence of a starting steam source, reducing the risk of water ingress into the turbine and adapting to the unit's start-up conditions.
Smart Images
Figure CN223647882U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of thermal power unit technology, specifically to a desuperheating device for the main steam supply shaft seal of a thermal power unit. Background Technology
[0002] In conventional thermal power turbines, the normal steam source for shaft seals comes from the unit's auxiliary steam header. Other available steam sources include the reheat cold section and main steam. When using main steam to supply steam for shaft seals, the main steam pressure and temperature are very high, placing high demands on the steam seal regulating valve. Furthermore, achieving the required shaft seal steam temperature to match the metal temperature of the upper wall of the regulating stage cylinder during cold starts is difficult or impossible. Therefore, even if a subsystem for supplying shaft seal steam with reduced pressure from main steam is set up, it is rarely used in practice. Based on these reasons, large units above 300MW currently mainly supply shaft seal steam through external auxiliary steam. In newly built thermal power units, some have eliminated the main steam source, but existing units, due to historical reasons, can only rely on main steam for startup when there is no external starting steam source.
[0003] Therefore, it is necessary to design a desuperheating device for the main steam supply shaft seal of thermal power units to solve the above problems. Utility Model Content
[0004] The purpose of this utility model is to provide a main steam supply shaft seal desuperheating device for thermal power units, which has the advantages of facilitating the adjustment of the main steam temperature and maintaining the shaft seal steam temperature consistent with the metal temperature of the upper wall of the inner cylinder of the regulating stage. It solves the problem that it is impossible to accurately control the steam temperature and that it is difficult to maintain the shaft seal steam temperature consistent with the metal temperature of the upper wall of the inner cylinder of the regulating stage.
[0005] To achieve the above objectives, this utility model provides the following technical solution: a main steam supply shaft seal desuperheating device for thermal power units, comprising a steam desuperheating station, a main steam pressure regulating valve connected to one side of the steam desuperheating station via a pipeline, an overpressure safety valve connected to one side of the steam desuperheating station via a pipeline, a manual shut-off valve connected to one side of the overpressure safety valve via a pipeline, a check valve connected to one side of the manual shut-off valve via a pipeline, an auxiliary steam pressure regulating station connected to one side of the check valve via a pipeline, and a steam turbine connected to one side of the auxiliary steam pressure regulating station via a pipeline.
[0006] Preferably, one side of the main steam pressure regulating valve is connected to a main steam inlet pipe via a pipeline.
[0007] Preferably, the auxiliary steam pressure regulating station is connected to a steam seal pipe, and one side of the steam seal pipe is connected to the steam turbine.
[0008] Preferably, the surface of the steam seal pipe is connected to a steam seal regulating valve.
[0009] Preferably, a steam flow sensor, a pressure sensor, and a temperature sensor are respectively installed on the surface of the steam turbine, and the steam flow sensor, pressure sensor, and temperature sensor are electrically connected to a controller.
[0010] Preferably, the controller is electrically connected to an alarm module, which includes a voice alarm and a flashing light.
[0011] Compared with the prior art, the beneficial effects of this utility model are as follows:
[0012] 1. This utility model supplies the main steam to the shaft seal after de-cooling and depressurizing, and adjusts the temperature difference between the main steam supply to the shaft seal and the high-pressure shaft seal to be controlled within 50°C as specified in the regulations, thereby reducing the impact of temperature difference on bearing vibration and ensuring the reliability of the unit.
[0013] 2. This utility model enables a 300MW thermal power unit to start up by self-supplying steam to the shaft seal after main steam desuperheating without a starting steam source. The main steam supply to the shaft seal is reduced by the added steam desuperheating station to match the temperature of the high and medium pressure shaft seal. It adopts the advanced drainage design concept of the current turbine bypass and cooling system to ensure smooth drainage of the system and reduce the risk of water ingress into the turbine. The shaft seal steam temperature is adjusted by feedforward and feedback. The desuperheating water control has strong anti-interference ability, sensitive response, and adaptability to the unit start-up conditions. After the steam desuperheating station is put into automatic mode, it can intelligently adjust the main steam supply to the shaft seal temperature according to the shaft seal temperature. Attached Figure Description
[0014] Figure 1 This is a schematic diagram illustrating the principle of this utility model;
[0015] Figure 2 This is a flowchart illustrating the system principle of this utility model.
[0016] In the diagram: 1. Steam desuperheating station; 2. Main steam pressure regulating valve; 3. Overpressure safety valve; 4. Manual shut-off valve; 5. Check valve; 6. Auxiliary steam pressure regulating station; 7. Steam turbine; 8. Main steam inlet pipe; 9. Steam seal pipe; 10. Steam seal regulating valve; 11. Steam flow sensor; 12. Pressure sensor; 13. Temperature sensor; 14. Controller; 15. Alarm module; 16. Voice alarm; 17. Flashing light. Detailed Implementation
[0017] Please see Figures 1-2A main steam supply shaft seal desuperheating device for a thermal power unit includes a steam desuperheating station 1. One side of the steam desuperheating station 1 is connected via a pipeline to a main steam pressure regulating valve 2. Another side of the steam desuperheating station 1 is connected via a pipeline to an overpressure safety valve 3. A third side of the overpressure safety valve 3 is connected via a pipeline to a manual shut-off valve 4. A fourth side of the manual shut-off valve 4 is connected via a pipeline to a check valve 5. A fifth side of the check valve 5 is connected via a pipeline to an auxiliary steam pressure regulating station 6. A sixth side of the auxiliary steam pressure regulating station 6 is connected via a pipeline to a steam turbine 7. By setting up the steam desuperheating station 1, the main steam pressure regulating valve 2, the overpressure safety valve 3, the manual shut-off valve 4, the check valve 5, and the auxiliary steam pressure regulating station 6, the steam temperature is effectively regulated. After the main steam is desuperheated and depressurized, it is supplied to the shaft seal. The deviation between the main steam supply temperature to the shaft seal and the high-pressure shaft seal supply temperature is adjusted and controlled within 50°C as specified in the regulations, reducing the impact of temperature difference on bearing vibration and ensuring the reliability of the unit.
[0018] Please see Figure 1 One side of the main steam pressure regulating valve 2 is connected to the main steam inlet pipe 8 through a pipeline. By setting the main steam inlet pipe 8, it is convenient to connect with the steam equipment and facilitate the delivery of steam.
[0019] Please see Figure 1 The auxiliary steam pressure regulating station 6 is connected to the steam seal pipe 9, and one side of the steam seal pipe 9 is connected to the steam turbine 7.
[0020] Please see Figure 1 The surface of the steam seal pipe 9 is connected to the steam seal regulating valve 10. By setting the steam seal pipe 9 and the steam seal regulating valve 10, the temperature-controlled steam is delivered to the steam turbine 7, and the amount of steam delivered can be adjusted.
[0021] Please see Figure 2 Steam flow sensor 11, pressure sensor 12 and temperature sensor 13 are respectively installed on the surface of steam turbine 7. Steam flow sensor 11, pressure sensor 12 and temperature sensor 13 are electrically connected to controller 14. By setting steam flow sensor 11, pressure sensor 12 and temperature sensor 13, the steam flow, pressure and temperature entering steam turbine 7 can be detected and the data can be monitored in real time.
[0022] Please see Figure 2 The controller 14 is electrically connected to an alarm module 15, which includes a voice alarm 16 and a flashing light 17. By setting the voice alarm 16 and the flashing light 17, the controller can alert the operator when data abnormalities are encountered, so that the operator can take appropriate measures in a timely manner.
[0023] The pressure is adjusted to 0.63-1.30 MPa.g by the main steam pressure regulating valve 2, and the temperature is adjusted to 250-350℃ by the steam desuperheating station 1. After desuperheating, the steam is led to the pipeline before the original auxiliary steam shaft seal pressure regulating station. Finally, after secondary pressure reduction by the auxiliary steam pressure regulating station 6, the shaft seal steam is supplied. After the modification, the temperature of the main steam supplied to the shaft seal is adjustable, which can meet the requirements of the shaft seal steam parameters during the start-up of the turbine 7 when there is no auxiliary steam.
[0024] Steam flow sensor 11, pressure sensor 12 and temperature sensor 13 detect the flow rate, pressure and temperature of steam inside steam turbine 7 and feed the data back to controller 14. Controller 14 compares the data with pre-stored data. If the data is abnormal, it controls voice alarm 16 to issue a voice alarm and flashing light 17 to promptly remind relevant personnel.
[0025] In summary, the main steam supply shaft seal desuperheating device of this thermal power unit, through steam desuperheating station 1, main steam pressure regulating valve 2, overpressure safety valve 3, manual shut-off valve 4, check valve 5, and auxiliary steam pressure regulating station 6, solves the problem of not being able to accurately control the steam temperature and the difficulty in maintaining the shaft seal steam temperature consistent with the metal temperature of the inner cylinder wall of the regulating stage.
Claims
1. A desuperheating device for the main steam supply shaft seal of a thermal power unit, comprising a steam desuperheating station (1), characterized in that: One side of the steam desuperheating station (1) is connected to a main steam pressure regulating valve (2) via a pipeline. One side of the steam desuperheating station (1) is connected to an overpressure safety valve (3) via a pipeline. One side of the overpressure safety valve (3) is connected to a manual shut-off valve (4) via a pipeline. One side of the manual shut-off valve (4) is connected to a check valve (5) via a pipeline. One side of the check valve (5) is connected to an auxiliary steam pressure regulating station (6) via a pipeline. One side of the auxiliary steam pressure regulating station (6) is connected to a steam turbine (7) via a pipeline.
2. The desuperheating device for the main steam supply shaft seal of a thermal power unit according to claim 1, characterized in that: One side of the main steam pressure regulating valve (2) is connected to the main steam inlet pipe (8) via a pipeline.
3. The desuperheating device for the main steam supply shaft seal of a thermal power unit according to claim 1, characterized in that: The auxiliary steam pressure regulating station (6) is connected to a steam seal pipe (9), and one side of the steam seal pipe (9) is connected to the steam turbine (7).
4. The desuperheating device for the main steam supply shaft seal of a thermal power unit according to claim 3, characterized in that: The surface of the steam seal pipe (9) is connected to a steam seal regulating valve (10).
5. The desuperheating device for the main steam supply shaft seal of a thermal power unit according to claim 1, characterized in that: The surface of the steam turbine (7) is respectively equipped with a steam flow sensor (11), a pressure sensor (12) and a temperature sensor (13), and the steam flow sensor (11), pressure sensor (12) and temperature sensor (13) are electrically connected to a controller (14).
6. A desuperheating device for the main steam supply shaft seal of a thermal power unit according to claim 5, characterized in that: The controller (14) is electrically connected to an alarm module (15), which includes a voice alarm (16) and a flashlight (17).