System for third-gear air leakage treatment of front shaft seal of power generation steam turbine

Abstract

The utility model belongs to the technical field of power generation steam turbines, and particularly discloses a system for third-gear steam leakage treatment of a front shaft seal of a power generation steam turbine, which comprises a steam turbine, a low-pressure heater connected onto the steam turbine, a front shaft seal and a rear shaft seal arranged on the steam turbine, and a pressure equalizing box communicated onto the front shaft seal and the rear shaft seal. A front shaft seal manual valve and a rear shaft seal manual valve are arranged on pipelines of the front shaft seal and the pressure equalizing box respectively, a temperature reducing water pipeline is arranged on the pipeline of the rear shaft seal and the pressure equalizing box, a control valve is arranged on the temperature reducing water pipeline, a steam branch pipeline is arranged on the pipeline of the front shaft seal and the pressure equalizing box and communicated with a low-pressure heater, and a control valve is arranged on the steam branch pipeline. In order to solve the problem of overpressure of the surge tank caused by overlarge air leakage of the front shaft seal in the prior art, the steam branching pipeline is arranged on the pipeline of the front shaft seal and the surge tank, so that the effect of shunting steam leaked from the front shaft seal is achieved, and the problem that the pressure of the surge tank is too high due to overlarge air leakage of the front shaft seal is solved. And the safe operation of the power generation steam turbine is influenced by the overpressure of the surge tank.

Description

Technical Field

[0001] The utility model relates to the technical field of power generation steam turbines, in particular to a system for treating the third-gear steam leakage of a front shaft seal of a power generation steam turbine. Background Art

[0002] A steam turbine, also known as a steam turbine engine, is a rotary steam-powered device that uses steam as its motive force, converting its thermal energy into mechanical work. A steam turbine consists of a rotating part, including the main shaft, impeller, moving blades, and couplings, and a stationary part, including the steam inlet, cylinder, partition, stationary blade grid, steam seals, and bearings. Its operating principle is as follows: Steam from the boiler enters the turbine, passes through a fixed nozzle, becomes an accelerated airflow, and is then sprayed onto the blades, causing the bladed rotor to rotate and simultaneously perform external work. Steam turbines offer advantages such as high single-unit power, high efficiency, and long life. They are the most widely used prime mover in modern thermal power plants and are also used in the metallurgical and chemical industries, as well as in ship propulsion systems.

[0003] As a crucial thermal equipment in power plants, steam turbines occupy a crucial production role in thermal power generation systems. However, shaft seal leakage has long been a major challenge plaguing the stable operation of steam turbines. This not only wastes resources but also pollutes the environment. Excessive steam leakage from the high- and medium-pressure cylinder shafts causes steam to leak from the inside out. This leakage can flow down the shaft into the bearings, directly heating the bearings and introducing water into the lubricating oil. This deteriorates the lubricating oil, disrupting bearing lubrication and potentially causing tungsten buildup in the bearings, leading to serious accidents. Excessive front seal leakage can also lead to overpressure in the pressure equalizing tank, compromising the safe operation of the turbine.

[0004] To solve the above problems, the utility model provides a system for treating the third-stage steam leakage of the front shaft seal of a power generation steam turbine, which solves the problem that when the front shaft seal leakage is too large, the pressure equalizing box will be over-pressurized, affecting the safe operation of the power generation steam turbine. Utility Model Content

[0005] The purpose of the utility model is to provide a system for treating the third-stage steam leakage of the front shaft seal of a power generation steam turbine, so as to solve the problem that the front shaft seal of the steam turbine leaks too much, causing the pressure equalizing box to be over-pressurized and thus affecting the safe operation of the power generation steam turbine.

[0006] To achieve the above-mentioned purpose, the basic solution provided by the utility model is: a system for treating the third-stage steam leakage of the front shaft seal of a power generation steam turbine, comprising a steam turbine, a low-pressure heater being connected to the steam turbine, a front shaft seal being provided at one end of the steam turbine, and a rear shaft seal being provided at the other end of the steam turbine, a pressure equalizing box being connected to the front shaft seal and the rear shaft seal, a front shaft seal manual valve and a rear shaft seal manual valve being provided on the pipes connecting the front shaft seal and the rear shaft seal with the pressure equalizing box, respectively, a cooling water pipe being provided on the pipe connecting the rear shaft seal with the pressure equalizing box, a cooling water control valve being provided on the cooling water pipe, a steam branch pipe being provided on the pipe connecting the front shaft seal with the pressure equalizing box and the pipe connecting the steam turbine with the low-pressure heater, and a steam branch pipe being provided on the steam branch pipe.

[0007] The working principle of the utility model is that when the steam turbine starts to run, the front shaft seal manual valve, the rear shaft seal manual valve, the steam shunt control valve and the attemperating water control valve are first opened. When the front shaft seal of the steam turbine leaks steam, part of the steam leaked from the third gear of the front shaft seal enters the equalizing tank through the pipeline, and part enters the low-pressure heater through the steam shunt pipeline, so that the leaked steam is divided into two paths, reducing the steam entering the equalizing tank, thereby reducing the pressure of the equalizing tank. At the same time, the attemperating water enters the rear shaft seal through the pipeline to cool the rear shaft seal.

[0008] The beneficial effect of the present invention is that the present invention realizes the effect of diverting the steam leaking from the front shaft seal by arranging a steam branch pipe on the pipe between the front shaft seal and the pressure equalizing box. This design can divide the steam leaking from the front shaft seal into two paths, reducing the pressure of the pressure equalizing box while allowing a part of the leaked steam to enter the low-pressure heater for use in heating the condensate produced by the exhaust steam of the turbine.

[0009] Option 2, which is the preferred option of the basic option, is provided with a PT100 thermal resistor on the low-pressure heater, and a cooling water branch pipe is connected to the steam branch pipe and the cooling water pipe, and a cooling water branch pipe is provided on the cooling water branch pipe, and the cooling water branch pipe is connected to the low-pressure heater; the PT100 thermal resistor can monitor the temperature of the low-pressure heater in real time. When the temperature of the low-pressure heater is too high, the staff opens the cooling water branch control valve and uses the cooling water in the cooling water branch pipe to cool the low-pressure heater.

[0010] Option three is the preferred option of the basic option. An atomizing nozzle is provided in one end of the cooling water branch pipe connected to the steam branch pipe. The atomizing nozzle can atomize the cooling water in the cooling water branch pipe to prevent water hammer from causing pipeline vibration, and at the same time can also achieve the effect of uniform cooling.

[0011] Option 4, which is the preferred option of the basic option, is that a pressure gauge is provided on the pressure equalizing box, which can monitor the pressure on the pressure equalizing box in real time.

[0012] Option 5 is the preferred option of the basic option. The specification of the steam branch pipe is DN80, and the specification of the cooling water branch pipe is; since the amount of cooling water used is small and it needs to be atomized when entering the steam branch pipe, a DN15 pipe is used. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 The utility model is a structural schematic diagram of a system for treating the third-stage steam leakage of the front shaft seal of a power generation steam turbine. DETAILED DESCRIPTION

[0014] The present invention is further described in detail below through specific implementation methods:

[0015] The figure marks in the drawings of the specification include: 1. steam turbine; 2. low-pressure heater; 3. front shaft seal; 4. rear shaft seal; 5. equalizing pressure box; 6. front shaft seal manual valve; 7. rear shaft seal manual valve; 8. cooling water pipeline; 9. cooling water control valve; 10. steam branch pipeline; 11. steam branch control valve; 12. PT100 thermal resistor; 13. cooling water branch pipeline; 14. cooling water branch control valve; 15. atomizing nozzle; 16. pressure gauge.

[0016] like Figure 1 The figure shows a system for treating steam leakage in the third gear of the front shaft seal of a power generation steam turbine, comprising a steam turbine 1, a low-pressure heater 2 connected to the steam turbine 1, a PT100 thermal resistor 12 provided on the low-pressure heater 2, a front shaft seal 3 provided at one end of the steam turbine 1, a rear shaft seal 4 provided at the other end of the steam turbine, a pressure equalizing tank 5 connected to the front shaft seal 3 and the rear shaft seal 4, a pressure gauge 16 provided on the pressure equalizing tank 5, a front shaft seal manual valve 6 and a rear shaft seal manual valve 7 provided on the pipelines connecting the front shaft seal 3 and the rear shaft seal 4 to the pressure equalizing tank 5, respectively, a cooling water pipeline 8 provided on the pipeline connecting the rear shaft seal 4 to the pressure equalizing tank 5, and a cooling water control valve 16 provided on the cooling water pipeline 8. Valve 9, a steam branch pipe 10 is provided on the pipe connecting the front shaft seal 3 and the pressure equalizing box 5 and the pipe connecting the turbine 1 and the low-pressure heater 2. The specification of the steam branch pipe 10 is DN80. A steam branch control valve 11 is provided on the steam branch pipe 10. A cooling water branch pipe 13 is connected to the steam branch pipe and the cooling water pipe. The specification of the cooling water branch pipe 13 is DN15. A cooling water branch control valve 14 is provided on the cooling water branch pipe 13. The cooling water branch pipe 13 is connected to the low-pressure heater 2. An atomizing nozzle 15 is provided in the end of the cooling water branch pipe 13 connecting to the steam branch pipe 10.

[0017] The implementation method of this embodiment is as follows: when the steam turbine 1 starts to run, the front shaft seal manual valve 6, the rear shaft seal manual valve 7, the steam branch control valve 11 and the desuperheating water control valve 9 are first opened. When the front shaft seal 3 of the steam turbine 1 leaks steam, part of the steam leaked from the third gear of the front shaft seal 3 enters the equalizing tank 5 through the pipeline, and part enters the low-pressure heater 2 through the steam branch pipe 10 to heat the condensate generated by the exhaust steam of the steam turbine 1. At the same time, the pressure gauge 16 on the equalizing tank 5 can measure the pressure of the equalizing tank 5 in real time, and the PT100 thermal resistor 12 on the low-pressure heater 2 can measure the temperature of the low-pressure heater 2 in real time. When the temperature of the low-pressure heater 2 is too high, the staff opens the desuperheating water branch control valve 14, and then part of the desuperheating water in the desuperheating water pipe 8 passes through the desuperheating water branch pipe 13, and then the atomized desuperheating water is sprayed into the low-pressure heater 2 through the atomizing nozzle 15 for cooling, and the other part of the desuperheating water enters the rear shaft seal 4 through the pipeline to cool the rear shaft seal 4.

[0018] The above is only an embodiment of the present invention, and the commonly known specific structures and characteristics of the scheme are not described in detail here. It should be pointed out that for those skilled in the art, several modifications and improvements can be made without departing from the structure of the present invention, and these should also be regarded as the scope of protection of the present invention. These will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection claimed by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A system for treating third-stage gas leakage in the front shaft seal of a power generation steam turbine, characterized in that: The invention comprises a steam turbine (1), wherein the steam turbine (1) is connected to a low-pressure heater (2), a front shaft seal (3) is provided at one end of the steam turbine (1), a rear shaft seal (4) is provided at the other end of the steam turbine (1), a pressure equalizing box (5) is connected to the front shaft seal (3) and the rear shaft seal (4), a front shaft seal manual valve (6) and a rear shaft seal manual valve (7) are provided on the pipelines connecting the front shaft seal (3) and the rear shaft seal (4) to the pressure equalizing box (5), respectively, a cooling water pipeline (8) is provided on the pipeline connecting the rear shaft seal (4) to the pressure equalizing box (5), a cooling water control valve (9) is provided on the cooling water pipeline (8), a steam branch pipeline (10) is provided on the pipeline connecting the front shaft seal (3) to the pressure equalizing box (5) and the pipeline connecting the steam turbine (1) to the low-pressure heater (2), and a steam branch control valve (11) is provided on the steam branch pipeline (10).

2. A system for treating gas leakage in the third gear of the front shaft seal of a power generation steam turbine according to claim 1, characterized in that: The low-pressure heater (2) is provided with a PT100 thermal resistor (12), the steam branch pipe (10) and the superheated water pipe (8) are connected to a superheated water branch pipe (13), the superheated water branch pipe (13) is provided with a superheated water branch control valve (14), and the superheated water branch pipe (13) is connected to the low-pressure heater (2).

3. A system for treating gas leakage in the third gear of the front shaft seal of a power generation steam turbine according to claim 2, characterized in that: An atomizing nozzle (15) is provided in one end of the desuperheated water branch pipe (13) that is in communication with the steam branch pipe (10).

4. A system for treating gas leakage in the third gear of the front shaft seal of a power generation steam turbine according to claim 1, characterized in that: The pressure equalizing box (5) is provided with a pressure gauge (16).

5. The system for treating gas leakage in the third gear of the front shaft seal of a power generation steam turbine according to claim 2, characterized in that: The specification of the steam branch pipe (10) is DN80, and the specification of the desuperheated water branch pipe (13) is DN15.

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