Shaft seal hot standby operation system and operation method

Abstract

The invention relates to a shaft seal heat standby operation system and method, the system comprises an auxiliary steam heat standby subsystem, a steam turbine, a condenser and a low-pressure heater, and the steam turbine is connected with a shaft seal steam supply main pipe; a steam outlet of the auxiliary steam heat standby subsystem is respectively connected with the shaft seal steam supply main pipe, the condenser and the low-pressure heater through a shaft seal auxiliary steam pipe, a first drain pipe and a second drain pipe; the shaft seal auxiliary steam pipe, the first drain pipe and the second drain pipe are communicated with a shaft seal adjusting valve, a first drain electric door and a second drain electric door respectively. The temperature of the shaft seal heat standby steam can be effectively guaranteed, meanwhile, the shaft seal heat standby steam source is recycled and drained to the low-pressure heater, and the safety and economical efficiency of a unit are improved.

Description

Technical Field

[0001] The invention relates to the technical field of steam turbine shaft seals, and in particular to a shaft seal hot standby operation system and an operation method. Background Art

[0002] The function of the shaft seal system is to prevent steam from leaking from the inside to the outside along the shaft ends of the high and medium pressure cylinders, or even from entering the bearing box to cause water to enter the lubricating oil, or air to leak from the outside to the inside into the low pressure cylinder and destroy the vacuum of the unit, as well as to recover the working fluid, reduce heat loss, and improve the environmental conditions of the steam turbine plant.

[0003] The shaft seal system is generally a self-sealing system, which means that when the unit is operating normally, the leaking steam from the shaft seal of the high-pressure cylinder passes through the medium-pressure cylinder to supply steam to the shaft seal of the low-pressure cylinder, and the excess leaking steam overflows to the condenser through the overflow station. During the low-load operation stage, the steam supply for the steam seal is provided by the auxiliary steam header through the shaft seal auxiliary steam mother pipe, acting as a backup system.

[0004] However, since the steam supply of the shaft seal auxiliary steam main pipe is in the hot standby stage during the self-sealing stage of the unit, the steam does not flow, and the drain generated in the pipeline will accumulate and cause the auxiliary steam temperature to decrease. It is necessary to drain the drain into the condenser regularly. At the same time, in order to ensure the temperature of the auxiliary steam, it is necessary to increase the temperature of the hot standby shaft seal auxiliary steam by heating or mixing high-temperature steam. Then the auxiliary steam with increased temperature will enter the condenser together with the drain. This not only wastes the auxiliary steam of the unit, but also increases the heat load of the condenser, which is not conducive to the economy of the unit. Therefore, this invention provides a shaft seal hot standby operation system and operation method to solve the above problems. Summary of the invention

[0005] The present invention provides a shaft seal hot standby operation system and operation method, which can effectively ensure the hot standby steam temperature, enable the stable implementation of the turbine shaft seal, and improve the safety of the unit.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A shaft seal hot standby operation system comprises an auxiliary steam hot standby subsystem, a steam turbine, a condenser and a low-pressure heater, wherein the steam turbine is connected to a shaft seal steam supply main pipe;

[0008] The steam outlet of the auxiliary steam hot standby subsystem is respectively connected to the shaft seal steam supply main pipe, the condenser and the low-pressure heater via a shaft seal auxiliary steam pipe, a first drain pipe and a second drain pipe;

[0009] The shaft seal auxiliary steam pipe, the first drain pipe and the second drain pipe are respectively connected to a shaft seal regulating valve, a first drain electric door and a second drain electric door.

[0010] Preferably, the auxiliary steam hot standby subsystem comprises an auxiliary steam header, a heating device and a temperature measuring device;

[0011] The steam outlet of the auxiliary steam header is connected to a shaft seal auxiliary steam main pipe, the shaft seal auxiliary steam main pipe is connected in parallel with a heating pipe, and the heating device is installed on the heating pipe;

[0012] The temperature measuring device is arranged at the connection between the shaft seal auxiliary steam main pipe and the shaft seal auxiliary steam pipe, is used to measure the temperature of the auxiliary steam, and is used in conjunction with the heating device.

[0013] Preferably, the shaft seal auxiliary steam main pipe comprises a first auxiliary steam main pipe, an auxiliary steam supply pipe and a second auxiliary steam main pipe, the auxiliary steam supply pipe is connected in parallel with the heating pipe, and the second auxiliary steam main pipe is connected with the shaft seal auxiliary steam pipe, the first drain pipe and the second drain pipe;

[0014] The first auxiliary steam main pipe is equipped with an auxiliary steam to shaft seal steam supply electric door, and the auxiliary steam supply pipe is equipped with a shaft seal steam supply electric door.

[0015] Preferably, a check valve is installed on the second drain pipe between the second drain electric door and the low-pressure heater.

[0016] An operating method of the above-mentioned shaft seal hot standby operating system comprises:

[0017] Before the unit is started, the first drain electric door is opened, the shaft seal regulating valve and the second drain electric door are closed, and the auxiliary steam in the auxiliary steam hot standby subsystem enters the condenser through the first drain pipe until the unit is started;

[0018] When the unit is started and the shaft seal system is not self-sealed or in the low-load stage, the shaft seal regulating valve is opened, the first drain electric door and the second drain electric door are closed, and the auxiliary steam and drain in the auxiliary steam hot standby subsystem enter the shaft seal steam supply main pipe through the shaft seal auxiliary steam pipe to seal the turbine shaft;

[0019] When the unit is under a certain load and the shaft seal system is self-sealing, the second drain electric door opens, the shaft seal regulating valve and the first drain electric door are closed, and the auxiliary steam in the auxiliary steam hot standby subsystem enters the low-pressure heater through the second drain pipe to maintain the continuous flow of auxiliary steam.

[0020] Preferably, when the unit is shut down urgently, the shaft seal regulating valve is opened, the first drain electric door and the second drain electric door are closed, and the auxiliary steam in the auxiliary steam hot standby subsystem enters the shaft seal steam supply main pipe through the shaft seal auxiliary steam pipe to seal the turbine.

[0021] Preferably, the operating system further comprises a temperature measuring device, the temperature measuring device is located at the steam outlet of the auxiliary steam hot standby subsystem, the auxiliary steam hot standby subsystem comprises an auxiliary steam header, a heating device, a first auxiliary steam main pipe, an auxiliary steam supply pipe, a heating pipe and a second auxiliary steam main pipe, the heating device is located in the heating pipe, and the operating method further comprises:

[0022] Before the unit is started and when its internal shaft seal system is self-sealing, when the auxiliary steam temperature in the pipeline measured by the temperature measuring device is lower than the first temperature value, the heating device is started, and the auxiliary steam in the auxiliary steam header passes through the first auxiliary steam main pipe, the heating device on the heating pipe and the second auxiliary steam main pipe to the pipeline measured by the temperature measuring device in sequence, so that the auxiliary steam temperature is between the first temperature value and the second temperature value, and the system operates normally. When the auxiliary steam temperature is higher than the third temperature value, the heating device is turned off, and the auxiliary steam in the auxiliary steam header passes through the first auxiliary steam main pipe, the auxiliary steam supply pipe and the second auxiliary steam main pipe to the pipeline measured by the temperature measuring device in sequence, so that the auxiliary steam temperature is between the first temperature value and the second temperature value, and the system operates normally until the auxiliary steam temperature is lower than the first temperature value, and then the heating device is started again, and the cycle is repeated; the third temperature value is greater than the second temperature value.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1. This shaft seal system can effectively ensure the temperature of shaft seal auxiliary steam at each stage of the unit, ensure the stable implementation of the turbine shaft seal, and improve the safety of the unit.

[0025] 2. By setting up a second drain pipe, the second drain pipe is connected to the low-pressure heater. In the self-sealing stage of the turbine shaft seal, that is, the auxiliary steam standby stage, the auxiliary steam and the drain formed by the auxiliary steam flow to the low-pressure heater, so that the auxiliary steam flows and the temperature of the shaft seal auxiliary steam is ensured, which is convenient for use and meets the use requirements. At the same time, the heat of the shaft seal standby auxiliary steam and the drain is recovered to the low-pressure heating condensate, which is more economical. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0027] Figure 1 Schematic diagram of the overall system of an embodiment of the present invention.

[0028] Description of reference numerals:

[0029] 1. Auxiliary steam hot standby subsystem; 101. Auxiliary steam manifold; 102. First auxiliary steam main; 103. Auxiliary steam supply pipe; 104. Second auxiliary steam main; 105. Heating pipe; 106. Heating device; 107. Temperature measuring device; 108. Auxiliary steam to shaft seal steam supply electric door; 109. Shaft seal steam supply electric door; 2. Steam turbine; 3. Condenser; 4. Low-pressure heater; 5. Shaft seal steam supply mother pipe; 6. Shaft seal auxiliary steam pipe; 7. First drain pipe; 8. Second drain pipe; 9. Shaft seal regulating valve; 10. First drain electric door; 11. Second drain electric door; 12. Check valve. DETAILED DESCRIPTION

[0030] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments 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 creative work are within the scope of protection of the present invention.

[0031] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0032] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0033] The embodiment of the present invention provides a shaft seal hot standby operation system, including an auxiliary steam hot standby subsystem 1, a steam turbine 2, a condenser 3 and a low-pressure heater 4, wherein the auxiliary steam hot standby subsystem 1 is used to increase auxiliary steam (hereinafter referred to as auxiliary steam). In this embodiment, the steam outlet of the auxiliary hot standby subsystem is divided into three routes, wherein the first route is connected to the shaft seal steam supply mother pipe 5 through the shaft seal auxiliary steam pipe 6, and a shaft seal regulating valve 9 is installed on the shaft seal auxiliary steam pipe 6. The on-off of the shaft seal auxiliary steam pipe 6 is controlled by the shaft seal regulating valve 9. When the shaft seal system of the steam turbine 2 is not self-sealed, the shaft seal steam supply mother pipe 5 at the steam turbine 2 is supplied to the shaft seal steam supply mother pipe 5 through the auxiliary steam hot standby subsystem 1. The auxiliary steam is supplied through the pipe 5, and then the auxiliary steam enters the shaft end of the steam turbine 2 for steam sealing, so as to ensure the normal operation of the steam turbine 2. The second path is connected to the condenser 3 with a first drain pipe 7, and a first drain valve electric door is installed on the first drain pipe 7 to control the on and off of the first drain pipe 7. Before the auxiliary steam hot standby subsystem 1 supplies auxiliary steam to the steam turbine 2, it is necessary to operate the first drain pipe 7 on the pipeline circulating the auxiliary steam. By closing the first drain electric door 10, the first drain pipe 7 is connected, and the auxiliary steam of the auxiliary steam hot standby subsystem 1 flows in the shaft seal auxiliary steam mother pipe therein, and then enters the first drain pipe 7, and finally enters The steam turbine 2 is in a normal working condition, and the shaft seal system of the steam turbine 2 is in a self-sealing stage. In order to ensure that the temperature of the auxiliary steam in the auxiliary steam hot standby subsystem 1 does not drop and the temperature difference with the metal temperature of the steam turbine 2 rotor is within the range required by the manufacturer, the second drain electric door 11 is opened, so that the auxiliary steam and drain in the auxiliary steam hot standby subsystem 1 enter the low-pressure heater through the second drain pipe 8. 4, so that the auxiliary steam can be kept in the flowing stage all the time. Once the steam starts to flow, its temperature is not easy to drop and can be maintained to ensure the temperature of the auxiliary steam when the steam turbine 2 uses the auxiliary steam for shaft sealing in the subsequent operation of the unit, to ensure the stable shaft sealing of the steam turbine 2 in the unit, and the auxiliary steam and drain entering the low-pressure heater 4 can heat the condensate passing through the low-pressure heater 4, recover heat to increase the temperature of the condensate, reduce the steam extraction of the medium and low pressure cylinders of the steam turbine 2 to a certain extent, and increase the power generation efficiency. Compared with the prior art in which the drain and the heated auxiliary steam are regularly discharged into the condenser 3, the economy of the unit is greatly improved.

[0034] Specifically, the auxiliary steam hot standby subsystem 1 includes an auxiliary steam header 101 and a heating device 106, wherein the steam outlet of the auxiliary steam header 101 is connected to the shaft seal auxiliary steam mother pipe, and the steam of the auxiliary steam header 101 is supplied through the shaft seal auxiliary steam mother pipe, wherein the shaft seal auxiliary steam mother pipe is connected in parallel with a heating pipe 105, and the heating device 106 is installed on the heating pipe 105. The heating device 106 can be an electric heater, which is used to increase the temperature of the auxiliary steam so that the temperature difference between the auxiliary steam and the metal temperature of the turbine 2 rotor is within the range required by the manufacturer, and the temperature value requirement for the auxiliary steam is met. When the auxiliary steam temperature is lower than the use requirement, the auxiliary steam is heated. The auxiliary steam enters the heating pipe 105, and then enters the shaft seal auxiliary steam main pipe again after being heated by the heating device 106 for supply; the auxiliary steam needs to be heated in the following cases: the temperature of the steam source of the auxiliary steam header 101 is reduced, resulting in a reduction in the temperature of the auxiliary steam discharged from the entire steam header; in addition, the outside temperature is low, resulting in an increase in condensation and drainage, and the temperature difference causes the auxiliary steam temperature of the shaft seal auxiliary steam main pipe to be low, etc.; and by setting an electric heater to increase the temperature of the auxiliary steam compared to using other high-temperature steam for mixing, there is no need to set up an extra high-temperature steam supply channel, which is more economical and practical overall. The temperature measuring device 107 can be a temperature sensor.

[0035] Specifically, the shaft seal auxiliary steam main pipe includes a first auxiliary steam main pipe 102, an auxiliary steam supply pipe 103 and a second auxiliary steam main pipe 104. The second auxiliary steam main pipe 104 is connected to the shaft seal auxiliary steam pipe 6, the first drain pipe 7 and the second drain pipe 8. The first auxiliary steam main pipe 102 is equipped with an auxiliary steam to shaft seal steam supply electric door 108, the auxiliary steam supply pipe 103 is equipped with a shaft seal steam supply electric door 109, the auxiliary steam supply pipe 103 is connected in parallel with the heating pipe 105, and the heating device 106 is installed on the heating pipe 105. Specifically, when the steam turbine 2 is not in use, close the auxiliary steam supply pipe 103. The electric steam supply door 108 for auxiliary steam to the shaft seal is sufficient. When the steam is supplied and the auxiliary steam temperature reaches the use requirements, the electric steam supply door 108 for auxiliary steam to the shaft seal and the electric steam supply door 109 for the shaft seal are opened, and the auxiliary steam is supplied to the outside through the first auxiliary steam main pipe 102, the auxiliary steam supply pipe 103 and the second auxiliary steam main pipe 104. When the steam is supplied and the auxiliary steam temperature does not reach the use requirements, the electric steam supply door 108 for auxiliary steam to the shaft seal is opened and the electric steam supply door 109 for the shaft seal is closed, and the auxiliary steam is supplied to the outside through the first auxiliary steam main pipe 102, the heating pipe 105 and the second auxiliary steam main pipe 104.

[0036] Specifically, a check valve 12 is installed on the second drain pipe 8 between the second drain electric door 11 and the low-pressure heater 4 to prevent the steam from the low-pressure heater 4 from flowing back into the shaft seal system to reduce the shaft seal steam temperature and endanger the safe operation of the entire unit.

[0037] The embodiment of the present invention further provides an operation method of a shaft seal hot standby operation system, which specifically includes:

[0038] Before the unit is started, that is, before the shaft seal system in the unit is put into operation, the first drain electric door 10 is opened, the first drain pipe 7 is connected, and the shaft seal regulating valve 9 and the second drain electric door 11 are closed. The auxiliary steam in the auxiliary steam hot standby subsystem enters the condenser 3 through the shaft seal auxiliary steam mother pipe and the first drain pipe 7 in turn, so as to heat the shaft seal auxiliary steam mother pipe to avoid the situation that the temperature of the pipeline is too low during the steam supply stage, which will reduce the temperature of the auxiliary steam, and ensure that the pipeline will not affect the auxiliary steam in the initial stage of subsequent steam supply; the above stage is until the unit is started, at which time the first drain electric door 10 is closed, the shaft seal regulating valve 9 is opened, and the auxiliary steam of the shaft seal system is put into operation.

[0039] When the unit is in the startup stage and before the shaft seal system in the unit is self-sealed or in the low-load stage, the shaft seal regulating valve 9 is opened, the shaft seal auxiliary steam pipe 6 is opened, and the first drain electric door 10 and the second drain electric door 11 are closed at the same time. The auxiliary steam in the auxiliary steam hot standby subsystem enters the shaft seal auxiliary steam pipe 6 through the shaft seal auxiliary steam mother pipe, and finally enters the shaft seal steam supply mother pipe 5 to seal the steam turbine 2 and perform auxiliary shaft sealing of the steam turbine 2.

[0040] When the unit is under a certain load and the shaft seal system in the unit is self-sealing, specifically including the load rising stage and the high load stage, the second drain electric door 11 is opened, the second drain pipe 8 is opened, and the shaft seal regulating valve 9 and the first drain electric door 10 are closed, so that the auxiliary steam and drain in the auxiliary steam hot standby subsystem enter the low-pressure heater 4 through the second drain pipe 8, which can not only maintain the continuous flow of auxiliary steam, so that the temperature of the auxiliary steam is maintained, and avoid the situation where the temperature of the auxiliary steam drops due to excessive drain, but also the auxiliary steam and drain entering the low-pressure heater 4 can heat the condensate heated by the low-pressure heater 4, thereby reducing the steam extraction amount of the medium and low pressure cylinders in the steam turbine 2, so that more steam can be used for power supply or other purposes. Compared with the existing shaft seal system in which the auxiliary steam does not flow, a large amount of drain will be generated, which can reduce the temperature of the auxiliary steam, and the water is regularly drained to the condenser 3, which will also increase the use burden of the condenser 3 and waste the auxiliary steam. The system can not only ensure the temperature of the auxiliary steam, but also recycle and reuse the energy of the auxiliary steam, thereby improving the economy of the unit as a whole. Moreover, the temperature of the auxiliary steam can be guaranteed in this stage. When the subsequent unit is tripped or reduced to low load, the auxiliary steam can meet the steam demand for the shaft seal of turbine 2, ensure the stable shaft seal of turbine 2, and ensure the safe operation of the unit.

[0041] Specifically, when the unit is shut down urgently, the shaft seal regulating valve 9 is opened, the first drain electric door 10 and the second drain electric door 11 are closed, and the auxiliary steam in the auxiliary steam hot standby subsystem enters the shaft seal steam supply main pipe 5 through the shaft seal auxiliary steam pipe 6 to seal the turbine 2.

[0042] Specifically, in order to ensure that the temperature of the auxiliary steam meets the use requirements before the unit is started and when the shaft seal system in the unit is self-sealed, that is, the difference between the temperature of the auxiliary steam and the metal temperature of the rotor of the steam turbine 2 is within the range required by the manufacturer, the operation method further includes:

[0043] Before the unit is started and when the shaft seal system in the unit is self-sealed, the self-sealing stage of the shaft seal system in the unit is the unit load increase and high load stage. When the auxiliary steam temperature in the pipeline measured by the temperature measuring device 107 is lower than the first temperature value, the heating device 106 is started, so that the auxiliary steam in the auxiliary steam header 101 passes through the first auxiliary steam main pipe 102, the heating device 106 on the heating pipe 105 and the second auxiliary steam main pipe 104 to the temperature measuring device 107 in sequence, until the auxiliary steam temperature of the pipeline at the temperature measuring device 107 is between the first temperature value and the second temperature value, the temperature of the auxiliary steam is maintained, and then the operation is continued, at which time the auxiliary steam can be supplied to the outside; when the auxiliary steam temperature is higher than the third temperature value, the heating device 106 is turned off and the operation is continued, at which time the auxiliary steam can be supplied to the outside, until the auxiliary steam temperature is lower than the first temperature value, the heating device 106 is started again, and the cycle is repeated. In the specific implementation process, the first temperature value, the second temperature value and the third temperature value and the power setting of the heating device 106 are all set by the operator according to the actual operation of the shaft seal system, and the difference between the first temperature value, the second temperature value and the third temperature value and the metal temperature of the rotor of the steam turbine 2 is within the range required by the manufacturer, that is, when the auxiliary steam temperature is lower than the first temperature value, the heating device 106 is turned on, so that the auxiliary steam temperature value can rise to between the first temperature value and the second temperature value, and the setting of the third temperature value is the same. When the auxiliary steam temperature is higher than the third temperature value, the heating device 106 is turned off, and the auxiliary steam temperature value will drop to between the first temperature value and the second temperature value. Of course, in addition to the heating of the heating device 106, the auxiliary steam temperature rise may also be affected by the increase of the steam source temperature and the external steam temperature, so that the auxiliary steam temperature value can rise to the third temperature. At this time, the auxiliary steam temperature meets the use requirements. In order not to waste the electric energy of the heating device 106, the heating device 106 is turned off to save electric energy, wherein the heating device 106 is an electric heater.

[0044] The temperature measuring device 107 is arranged as mentioned above to ensure that the temperature of the auxiliary steam always meets the use requirements when the auxiliary steam shaft seal is to be performed on the steam turbine 2 (auxiliary steam shaft seal is required during the start-up shaft seal operation stage of the steam turbine 2, when the unit is reduced to a low load stage, and when the steam turbine 2 is tripped), to ensure the stable operation of the steam turbine 2 shaft seal system through the auxiliary steam, and to ensure the stable and safe operation of the unit.

[0045] The above-mentioned embodiments are only preferred embodiments of the present invention and cannot be used to limit the scope of protection of the present invention. Any non-substantial changes and substitutions made by technicians in this field on the basis of the present invention shall fall within the scope of protection required by the present invention.

Claims

1. A shaft seal hot standby operation system, characterized in that: It includes an auxiliary steam hot standby subsystem, a steam turbine, a condenser and a low-pressure heater, wherein the steam turbine is connected to a shaft seal steam supply main pipe; The steam outlet of the auxiliary steam hot standby subsystem is respectively connected to the shaft seal steam supply main pipe, the condenser and the low-pressure heater via a shaft seal auxiliary steam pipe, a first drain pipe and a second drain pipe; The shaft seal auxiliary steam pipe, the first drain pipe and the second drain pipe are respectively connected to a shaft seal regulating valve, a first drain electric door and a second drain electric door.

2. The shaft seal hot standby operation system according to claim 1, characterized in that: The auxiliary steam hot standby subsystem includes an auxiliary steam header, a heating device and a temperature measuring device; The steam outlet of the auxiliary steam header is connected to a shaft seal auxiliary steam main pipe, the shaft seal auxiliary steam main pipe is connected in parallel with a heating pipe, and the heating device is installed on the heating pipe; The temperature measuring device is arranged at the connection between the shaft seal auxiliary steam main pipe and the shaft seal auxiliary steam pipe, is used to measure the temperature of the auxiliary steam, and is used in conjunction with the heating device.

3. The shaft seal hot standby operation system according to claim 2, characterized in that: The shaft seal auxiliary steam main pipe comprises a first auxiliary steam main pipe, an auxiliary steam supply pipe and a second auxiliary steam main pipe, the auxiliary steam supply pipe is connected in parallel with the heating pipe, and the second auxiliary steam main pipe is connected with the shaft seal auxiliary steam pipe, the first drain pipe and the second drain pipe; The first auxiliary steam main pipe is equipped with an auxiliary steam to shaft seal steam supply electric door, and the auxiliary steam supply pipe is equipped with a shaft seal steam supply electric door.

4. The shaft seal hot standby operation system according to claim 1, characterized in that: A check valve is installed on the second drain pipe between the second drain electric door and the low-pressure heater.

5. An operating method of the shaft seal hot standby operating system according to any one of claims 1 to 4, characterized in that: include: Before the unit is started, the first drain electric door is opened, the shaft seal regulating valve and the second drain electric door are closed, and the auxiliary steam in the auxiliary steam hot standby subsystem enters the condenser through the first drain pipe until the unit is started; When the unit is started and the shaft seal system is not self-sealed or in the low-load stage, the shaft seal regulating valve is opened, the first drain electric door and the second drain electric door are closed, and the auxiliary steam and drain in the auxiliary steam hot standby subsystem enter the shaft seal steam supply main pipe through the shaft seal auxiliary steam pipe to seal the turbine shaft; When the unit is under a certain load and the shaft seal system is self-sealing, the second drain electric door opens, the shaft seal regulating valve and the first drain electric door are closed, and the auxiliary steam in the auxiliary steam hot standby subsystem enters the low-pressure heater through the second drain pipe to maintain the continuous flow of auxiliary steam.

6. The operating method of the shaft seal hot standby operating system according to claim 5, characterized in that: When the unit is shut down urgently, the shaft seal regulating valve is opened, the first drain electric door and the second drain electric door are closed, and the auxiliary steam in the auxiliary steam hot standby subsystem enters the shaft seal steam supply main pipe through the shaft seal auxiliary steam pipe to seal the turbine shaft.

7. The operating method of the shaft seal hot standby operating system according to claim 6, characterized in that: The operating system further includes a temperature measuring device, which is located at the steam outlet of the auxiliary steam hot standby subsystem. The auxiliary steam hot standby subsystem includes an auxiliary steam header, a heating device, a first auxiliary steam main pipe, an auxiliary steam supply pipe, a heating pipe, and a second auxiliary steam main pipe. The heating device is located in the heating pipe. The operating method further includes: Before the unit is started and when its internal shaft seal system is self-sealing, when the auxiliary steam temperature in the pipeline measured by the temperature measuring device is lower than the first temperature value, the heating device is started, and the auxiliary steam in the auxiliary steam header passes through the first auxiliary steam main pipe, the heating device on the heating pipe and the second auxiliary steam main pipe to the pipeline measured by the temperature measuring device in sequence, so that the auxiliary steam temperature is between the first temperature value and the second temperature value, and the system operates normally. When the auxiliary steam temperature is higher than the third temperature value, the heating device is turned off, and the auxiliary steam in the auxiliary steam header passes through the first auxiliary steam main pipe, the auxiliary steam supply pipe and the second auxiliary steam main pipe to the pipeline measured by the temperature measuring device in sequence, so that the auxiliary steam temperature is between the first temperature value and the second temperature value, and the system operates normally until the auxiliary steam temperature is lower than the first temperature value, and then the heating device is started again, and the cycle is repeated; the third temperature value is greater than the second temperature value.

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