Drainage system of shaft seal cooler

Abstract

The utility model discloses a shaft seal cooler drainage system which comprises a shaft seal cooler, a drainage device, a clean drainage tank, a drainage pit valve and a condensate pump, one side of the water side of the shaft seal cooler is connected with the condensate pump through a pipeline, and the other side of the water side of the shaft seal cooler is connected with a boiler through a pipeline. One side of the steam side of the shaft seal cooler is connected with shaft seal steam through a pipeline, the other side of the steam side of the shaft seal cooler is connected with the drainage device through a pipeline, the other side of the steam side of the shaft seal cooler is connected with the drainage pit valve through a pipeline, and the other side of the drainage device is connected with the clean drainage tank through a pipeline. According to the shaft seal cooler drainage system, drainage water is drained to the clean drainage tank through the drainage device, the abnormal situation that vacuum leakage cannot be established at the water level or drainage water cannot be smoothly drained when the drainage water is drained to the condenser through a water seal is avoided, meanwhile, the drainage water is recycled, and the running economical efficiency and safety of a steam turbine are improved.

Description

Technical Field

[0001] This utility model belongs to the field of hydrophobic technology, specifically relating to a hydrophobic system for a shaft seal cooler. Background Technology

[0002] A shaft seal cooler is a device for recovering steam and heat from the shaft seal steam of a steam turbine. It uses a closed heat exchanger (shaft seal cooler) to heat the condensate from the turbine's shaft seal steam return steam to recover heat, while simultaneously cooling the return steam and condensing it into condensate, which is then returned to the condenser. Because the condenser operates under near-vacuum conditions during turbine operation, with an absolute pressure less than 10 kPa, directly connecting the shaft seal cooler condensate to the condenser would cause the condensate, steam, and some non-condensable gases on the steam side to be instantly drawn away by the condenser vacuum, making it impossible to control the shaft seal cooler water level and maintain the condenser vacuum. Therefore, power plants typically use water seals or multi-layer water seals on the condensate side to ensure drainage while maintaining the pressure difference between the two sides.

[0003] However, in actual power plant operation, due to the vast differences in operating conditions—such as turbine startup, normal operation, and shutdown—the flow rate of shaft seal steam and the vacuum degree of the condenser vary significantly. This means that when using water seals to drain water from the shaft seal cooler, the water level often fails to establish a vacuum or the drain cannot be discharged smoothly under different operating conditions. This is especially true for gas-fired combined cycle units used for peak shaving, which often operate on a two-shift system (day and night), with constantly changing turbine operating conditions. Even after the shaft seal cooler drain is normalized under one operating condition, problems arise under other conditions that cannot be maintained, significantly impacting personnel requirements and the unit's economic efficiency. Utility Model Content

[0004] To address the problems mentioned in the background art, this utility model provides a shaft seal cooler drainage system, which solves the problem of abnormal drainage of the shaft seal cooler caused by changes in turbine operating conditions.

[0005] To achieve the above objectives, this utility model provides the following technical solution: a shaft seal cooler drainage system, comprising a shaft seal cooler, a drainage device, a drainage outlet valve, a condensate pump, and a cleaning drainage tank. One water side of the shaft seal cooler is connected to the condensate pump via a pipe, and the other water side is connected to a boiler via a pipe. One steam side of the shaft seal cooler is connected to the shaft seal steam via a pipe, and the other steam side is connected to the drainage device via a pipe. The other steam side is connected to the drainage outlet valve via a pipe. The drainage device is connected to the cleaning drainage tank via a pipe and is used for draining water from the shaft seal cooler during normal operation. The condensate pump is a single unit.

[0006] Preferably, the drain valve is connected to the drain pit via a pipe and is used to drain water from the shaft seal cooler during emergency operation or maintenance.

[0007] Preferably, the drainage device can be an automatic drainage device, a drainage regulating valve, a water jet pump, a water pump, or other drainage equipment.

[0008] Preferably, there may be multiple condensate pumps.

[0009] Compared with the prior art, the beneficial effects of this utility model are:

[0010] Shaft seal coolers are crucial equipment in power plant steam-water systems. They recover the waste heat from high-temperature steam leaking from turbine shaft seals and transfer this heat to condensate via a shell-and-tube heat exchanger. Simultaneously, the cooled steam is condensed into condensate and returned to the condenser. However, gas-fired combined cycle units often operate on a two-shift system (day and night shifts), and the constantly changing turbine operating conditions mean that when using water seals to drain water from shaft seal coolers, the water level often fails to establish a vacuum or the condensate cannot be discharged smoothly under different operating conditions. This invention provides a shaft seal cooler condensate drainage system that uses a condensate draining device to discharge the condensate to a clean condensate tank. This avoids the abnormal situations where the water level fails to establish a vacuum or the condensate cannot be discharged smoothly when using water seals to drain to the condenser, while also recovering this condensate, thus improving the economy and safety of turbine operation. Attached Figure Description

[0011] The accompanying drawings are provided to further illustrate the present invention and form part of the specification. They are used together with the embodiments of the present invention to explain the present invention, but do not constitute a limitation thereof. In the drawings:

[0012] Figure 1 This is a schematic diagram of the drainage system of the shaft seal cooler of this utility model;

[0013] In the diagram: 1. Shaft seal cooler; 2. Drainage device; 3. Drainage to drain pit valve; 4. Condensate pump; 5. Boiler; 6. Shaft seal steam; 7. Cleaning drain tank; 8. Drain pit; 9. Shaft seal cooler fan; 10. Atmosphere; 11. Cleaning drain recovery valve; 12. Condenser. Detailed Implementation

[0014] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present utility model without creative effort are within the protection scope of the present utility model.

[0015] Please see Figure 1This utility model provides the following technical solution: a shaft seal cooler drainage system, including a shaft seal cooler 1, a drainage device 2, a drainage drain valve 3, a condensate pump 4, and a clean drainage tank 7. The water side of the shaft seal cooler 1 is connected to the condensate pump 4 through a pipe, the other water side of the shaft seal cooler 1 is connected to the boiler 5 through a pipe, the steam side of the shaft seal cooler 1 is connected to the shaft seal steam 6 through a pipe, the other steam side of the shaft seal cooler 1 is connected to the drainage device 2 through a pipe, the other steam side of the shaft seal cooler 1 is connected to the drainage drain valve 3 through a pipe, and the drainage device 2 is connected to the clean drainage tank 7 through a pipe. It is used to drain the shaft seal cooler 1 during normal operation. The condensate pump 4 is a single unit.

[0016] In this embodiment: the steam side of the shaft seal cooler 1 is connected to the shaft seal cooler fan 9 through a pipe, and the shaft seal cooler fan 9 is connected to the atmosphere 10 through a pipe, which is used to extract non-condensable gas in the shaft seal cooler 1 to the atmosphere 10.

[0017] In this embodiment, the drainage device 2 is connected to the clean drainage tank 7 via a pipe and is used to drain water from the shaft seal cooler 1 during normal operation.

[0018] In this embodiment: the clean condensate tank 7 is connected to the clean condensate recovery valve 11 through a pipe, the clean condensate recovery valve 11 is connected to the condenser 12 through a pipe, and the condenser 12 is connected to the condensate pump 4 through a pipe, so that the condensate from the shaft seal cooler 1 is recovered to the condenser 12 through the clean condensate tank 7 and the clean condensate recovery valve 11 during normal operation.

[0019] In this embodiment, the drain valve 3 is connected to the drain pit 8 via a pipe and is used to drain water from the shaft seal cooler 1 during emergency operation or maintenance.

[0020] In this embodiment, the drainage device 2 can be an automatic drainage device, a drainage regulating valve, a water jet pump, a water pump, or other drainage equipment.

[0021] In this embodiment: there is one condensate pump 4 and one shaft seal cooler fan 9. There can also be multiple condensate pumps 4 and multiple shaft seal cooler fans 9.

[0022] The working principle and usage process of this utility model are as follows: After installation, the shaft seal steam 6 is cooled by the shaft seal cooler 1, and most of it condenses into condensate and a small amount of non-condensable gas. The non-condensable gas is extracted to the atmosphere 10 by the shaft seal cooler fan 9. During normal operation, the condensate is discharged to the clean condensate tank 7 through the condensate drain device 2, and then recovered to the condenser 12 through the clean condensate recovery valve 11. The condensate pump 4 pressurizes the condensate, and after being heated by the shaft seal cooler 1, it goes to the boiler 5 for further heating. All electrical equipment in this device is powered by an external power source.

[0023] Finally, it should be noted that the above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A shaft seal cooler drainage system, comprising a shaft seal cooler (1), a drainage device (2), a drainage outlet valve (3), a condensate pump (4), and a cleaning drainage tank (7), characterized in that: The water side of the shaft seal cooler (1) is connected to the condensate pump (4) through a pipe, and the other side of the water side of the shaft seal cooler (1) is connected to the boiler (5) through a pipe. The steam side of the shaft seal cooler (1) is connected to the shaft seal steam (6) through a pipe, and the other side of the steam side of the shaft seal cooler (1) is connected to the drain device (2) through a pipe. The other side of the steam side of the shaft seal cooler (1) is connected to the drain drain valve (3) through a pipe. The drain device (2) is connected to the clean drain tank (7) through a pipe and is used to drain the shaft seal cooler (1) during normal operation. There is one condensate pump (4).

2. The shaft seal cooler drainage system according to claim 1, characterized in that: The drain valve (3) is connected to the drain pit (8) through a pipe and is used to drain water from the shaft seal cooler (1) during emergency operation or maintenance.

3. The shaft seal cooler drainage system according to claim 1, characterized in that: The drainage device (2) is one of the following drainage equipment methods: automatic drainage device, drainage regulating valve, water jet pump, and water pump.

4. The shaft seal cooler drainage system according to claim 1, characterized in that: There are multiple condensate pumps (4).

Images