CN114635758B - Ultra-supercritical unit shaft seal system and operation method - Google Patents
Ultra-supercritical unit shaft seal system and operation method Download PDFInfo
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- CN114635758B CN114635758B CN202210190540.5A CN202210190540A CN114635758B CN 114635758 B CN114635758 B CN 114635758B CN 202210190540 A CN202210190540 A CN 202210190540A CN 114635758 B CN114635758 B CN 114635758B
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- 238000000034 method Methods 0.000 title claims abstract description 13
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 40
- 230000001105 regulatory effect Effects 0.000 claims description 41
- 238000007789 sealing Methods 0.000 claims description 15
- 238000003303 reheating Methods 0.000 claims description 8
- 239000002184 metal Substances 0.000 claims description 3
- 230000001172 regenerating effect Effects 0.000 claims description 3
- 238000012544 monitoring process Methods 0.000 claims description 2
- 239000003507 refrigerant Substances 0.000 description 6
- 230000002209 hydrophobic effect Effects 0.000 description 3
- 238000005457 optimization Methods 0.000 description 3
- 238000011217 control strategy Methods 0.000 description 2
- 238000013461 design Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000009530 blood pressure measurement Methods 0.000 description 1
- 238000009529 body temperature measurement Methods 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000010248 power generation Methods 0.000 description 1
- 238000004781 supercooling Methods 0.000 description 1
- 230000008646 thermal stress Effects 0.000 description 1
- 238000010977 unit operation Methods 0.000 description 1
Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
- F01D11/00—Preventing or minimising internal leakage of working-fluid, e.g. between stages
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
- F01D21/00—Shutting-down of machines or engines, e.g. in emergency; Regulating, controlling, or safety means not otherwise provided for
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
- F01D21/00—Shutting-down of machines or engines, e.g. in emergency; Regulating, controlling, or safety means not otherwise provided for
- F01D21/003—Arrangements for testing or measuring
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
- F01D25/00—Component parts, details, or accessories, not provided for in, or of interest apart from, other groups
- F01D25/08—Cooling; Heating; Heat-insulation
- F01D25/10—Heating, e.g. warming-up before starting
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
- F01D25/00—Component parts, details, or accessories, not provided for in, or of interest apart from, other groups
- F01D25/08—Cooling; Heating; Heat-insulation
- F01D25/12—Cooling
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Turbine Rotor Nozzle Sealing (AREA)
Abstract
The invention discloses a shaft seal system of an ultra-supercritical unit and an operation method thereof. And steam inlet sides of the ultrahigh pressure cylinder, the high pressure cylinder, the medium pressure cylinder and the low pressure cylinder are supplied with steam by a shaft seal steam main pipe. Shaft seal leakage at two ends of the ultra-high pressure cylinder is led out through a pipeline and is connected with an exhaust pipeline of the high pressure cylinder, and shaft seal leakage at two ends of the high pressure cylinder is led out through a pipeline and is connected with a medium-low pressure communicating pipe. The shaft seal steam main pipe is provided with a path of temperature reduction water close to the low pressure cylinder side, and the temperature reduction water is taken from condensed water and is connected with the shaft seal steam main pipe. According to the invention, the shaft seal steam leakage at the two ends of the ultrahigh pressure cylinder and the high pressure cylinder is respectively recycled, and meanwhile, the shaft seal overflow steam is led to the low pressure heater, so that the heat economy of the unit is improved. The low-temperature water is introduced into the shaft seal steam position of the low-pressure cylinder, so that the problem of high shaft seal temperature of the low-pressure cylinder is effectively solved, and the operation safety and stability of the shaft seal system are improved.
Description
Technical Field
The invention relates to the technical field of turbine shaft seal system optimization, in particular to a shaft seal system of an ultra-supercritical unit and an operation method.
Background
In recent years, the ultra-supercritical technology is rapidly developed in China, and the put-in ultra-supercritical unit achieves good operation performance, and has better reliability, economy and flexibility, so that the ultra-supercritical technology represents the advanced technical level and development trend of the current thermal power generation.
The shaft seal system is an important component of the steam turbine, wherein the high-pressure shaft seal has the function of preventing high-temperature and high-pressure steam from leaking out of the cylinder, and the low-pressure shaft seal has the function of preventing air from leaking into the cylinder, so that the high-efficiency operation of the unit is ensured. The shaft seal system has strict requirements on steam supply temperature and pressure, so that the shaft seal of the steam turbine cannot generate excessive thermal stress, and supercooling or superheated steam is prevented from entering.
For the ultra-supercritical unit, as the unit operation parameters are high, auxiliary systems are numerous, the structure is complex, and higher requirements are put on the safety and stability of the operation of the shaft seal system. Therefore, for ultra-supercritical units, it is necessary to design and optimize the shaft seal system and ensure safe, reliable and economical operation of the shaft seal system.
Disclosure of Invention
In order to overcome the defects in the prior art, the invention aims to provide the shaft seal system of the ultra-supercritical unit and the operation method, different heat sources are adopted to supply auxiliary steam headers, so that the steam temperature and the steam pressure of the auxiliary steam headers for shaft seal supply are ensured, meanwhile, the temperature and the pressure of a main pipe for shaft seal supply are closely concerned, the shaft seal is reasonably utilized for steam leakage, and the safety, the stability and the economical efficiency of the operation of the shaft seal system are improved.
In order to achieve the above purpose, the technical scheme adopted by the invention is as follows:
The shaft seal system of the ultra-supercritical unit comprises an auxiliary steam header, and an ultra-high pressure cylinder, a medium pressure cylinder, a low pressure cylinder A and a low pressure cylinder B which are connected in sequence;
the steam at the outlet of the auxiliary steam header is connected with a shaft seal steam master pipe, steam inlet sides of the ultrahigh pressure cylinder, the high pressure cylinder, the medium pressure cylinder, the low pressure cylinder A and the low pressure cylinder B are respectively supplied with steam by the shaft seal steam master pipe, the shaft seal steam master pipe is provided with a pressure measuring point P 1 and two temperature measuring points T 1、T2, after the sealing of the shaft seal cavity is completed, the residual steam enters a shaft seal steam return master pipe through steam return pipelines, each steam return pipeline is provided with a steam return manual regulating valve, and the shaft seal steam return master pipe steam is sent to a shaft seal heater;
shaft seal leakage steam at two ends of the ultrahigh pressure cylinder is led out through a pipeline and is connected with an exhaust pipeline of the ultrahigh pressure cylinder, and a check valve is arranged on the pipeline; shaft seal steam leakage at two ends of the high-pressure cylinder is led out through a pipeline and is connected with a middle-low pressure communicating pipe, a shaft seal steam main pipe to a middle-low pressure communicating pipe electric valve is arranged on the pipeline, a drainage pipeline is arranged in front of the shaft seal steam main pipe to the middle-low pressure communicating pipe electric valve, a shaft seal steam leakage to a middle-low pressure communicating pipe drainage pneumatic valve is arranged on the drainage pipeline, and drainage goes to a drainage header of a condenser body;
the shaft seal steam main pipe is provided with a path of temperature reduction water close to the low pressure cylinder side, the temperature reduction water is taken from condensed water, and the temperature reduction water is connected with the shaft seal steam main pipe through a temperature reduction water electric valve and a temperature reduction water regulating valve.
The invention is further improved in that the auxiliary steam header is provided with a temperature measuring point T 6 and a pressure measuring point P 3, and the outlet steam of the auxiliary steam header is connected with a main steam pipe of the shaft seal through a shaft seal electric heater, an auxiliary steam supply shaft seal electric valve and an auxiliary steam supply shaft seal regulating valve in sequence.
The invention is further improved in that the shaft seal electric heater is provided with a parallel bypass, a shaft seal electric heater bypass electric valve is arranged on the bypass, and a shaft seal electric heater front electric valve is arranged in front of the shaft seal electric heater; the auxiliary steam supply shaft seal pipeline is provided with a parallel bypass, and an auxiliary steam supply shaft seal bypass electric valve is arranged on the parallel bypass; the main path and the bypass of the shaft seal electric heater and the main path and the bypass drain of the auxiliary steam supply shaft seal pipeline are both led to the drain header of the condenser body, and the drain pipeline is provided with a pneumatic valve; a temperature measuring point T 3 and a pressure measuring point P 2 are arranged in front of the auxiliary steam supply shaft seal electric valve.
The invention is further improved in that the shaft seal steam main pipe is connected with the condenser through the shaft seal overflow adjusting valve and the shaft seal overflow to the condenser electric valve, and meanwhile, the shaft seal steam main pipe is connected with the low-pressure heater through the shaft seal overflow adjusting valve and the shaft seal overflow to the low-pressure heater electric valve.
The invention is further improved in that the shaft seal steam main pipe is provided with a drain pipeline, the drain pipeline is provided with a shaft seal steam main pipe drain pneumatic valve, and drain water is sent to a drain header of the condenser body.
The invention is further improved in that the temperature measuring point T 4、T5 is arranged on the pipelines of the shaft seal steam leakage high-pressure cylinder exhaust pipeline and the medium-low pressure communicating pipe.
The invention is further improved in that the steam sources of the auxiliary steam header are respectively provided by the adjacent auxiliary steam header and the secondary reheating cold section steam supply auxiliary steam header.
An operation method of a shaft seal system of an ultra-supercritical unit comprises the following steps:
a. In the starting stage of the unit, the auxiliary steam header supplies steam from the adjacent auxiliary steam header, a front electric valve of the shaft seal electric heater, an auxiliary steam supply shaft seal electric valve and an auxiliary steam supply shaft seal regulating valve are opened, and a shaft seal electric heater bypass electric valve and an auxiliary steam supply shaft seal bypass electric valve are closed; monitoring a front temperature measuring point T 3 and a pressure measuring point P 2 of an auxiliary steam supply shaft seal electric valve, and a shaft seal steam main pipe temperature measuring point T 1、T2 and a pressure measuring point P 1, wherein an auxiliary steam supply shaft seal electric heater regulates the auxiliary steam temperature, and an auxiliary steam supply shaft seal regulating valve controls the shaft seal steam main pipe pressure; simultaneously opening a main shaft seal steam pipe drainage pneumatic valve, and opening a main shaft seal electric heater main path drainage pneumatic valve, a bypass drainage pneumatic valve, an auxiliary steam supply shaft seal main path drainage pneumatic valve and an auxiliary steam supply shaft seal bypass drainage pneumatic valve on a main shaft seal electric heater main path and a bypass drainage pipeline of the auxiliary steam supply shaft seal pipeline; closing a shaft seal overflow regulating valve, a shaft seal overflow to a condenser electric valve and a shaft seal overflow to a low-pressure heater electric valve, closing a shaft seal steam main pipe to a medium-low pressure communicating pipe electric valve, and closing a desuperheating water electric valve and a desuperheating water regulating valve;
b. When the unit is connected with the power grid and the load is continuously increased, as the secondary reheating cold-section steam is exhausted from the high-pressure cylinder, the metal temperature of the cylinder body can be better matched, the auxiliary steam header steam source is switched, and the adjacent auxiliary steam header provides the secondary reheating cold-section steam which is gradually switched; meanwhile, the shaft seal system is gradually changed into a self-sealing state, the auxiliary steam supply shaft seal regulating valve is gradually closed, when the auxiliary steam supply shaft seal regulating valve is fully closed, the shaft seal overflow regulating valve and the shaft seal overflow to the condenser electric valve are opened, the shaft seal system is in the self-sealing state, the shaft seal steam overflows and then goes to the condenser, and the shaft seal overflow regulating valve maintains the stability of the temperature and the pressure of the main pipe of the shaft seal steam; regarding the pipeline temperature T 5 of the shaft seal steam leakage to the medium-low pressure communicating pipe, gradually opening the shaft seal steam main pipe to the medium-low pressure communicating pipe electric valve after the temperature meets the requirement, closing the shaft seal steam main pipe drainage pneumatic valve, and closing the shaft seal electric heater main path, the bypass and the pneumatic valves on the auxiliary steam supply shaft seal pipeline main path and the bypass drainage pipeline;
c. When the unit load is stable or in a high-load running state, the display temperature T 2 of a temperature measuring point of a low-pressure cylinder side sealing steam main pipe is closely monitored, when the temperature is higher, a temperature-reducing water electric valve is opened, the opening degree of the temperature-reducing water regulating valve is regulated to control the temperature of the low-pressure cylinder side sealing steam, and when a unit regenerative system is put into operation, a shaft seal is opened to overflow to a low-pressure heater electric valve, and meanwhile, the shaft seal is closed to overflow to a condenser electric valve.
The invention has at least the following beneficial technical effects:
the invention provides an optimization scheme of a shaft seal system of an ultra-supercritical unit, which not only respectively recycles the shaft seal steam leakage at the two ends of an ultra-high pressure cylinder and a high pressure cylinder, but also introduces water for reducing temperature at the shaft seal steam position of a low pressure cylinder, thereby effectively solving the problem of high temperature of the shaft seal steam at the shaft seal of the low pressure cylinder after the shaft seal system is self-sealed.
Meanwhile, the overflow steam of the shaft seal is introduced into the low-pressure heater, and the heat of the overflow steam is utilized, so that the temperature of the outlet of the water supply side of the low-pressure heater is improved, and the thermal economy of the unit is improved.
The operation method of the shaft seal system not only considers the operation steps and the control strategy of the system when the unit is normally started, but also provides the control strategy of the shaft seal system under various operation states. The system control mode is flexible and simple, easy to operate and high in automation degree.
Drawings
Fig. 1 is a schematic structural view of the present invention.
The system comprises a steam turbine ultrahigh pressure cylinder 1, a steam turbine high pressure cylinder 2, a steam turbine medium pressure cylinder 3, a low pressure cylinder A4, a low pressure cylinder B5, an auxiliary steam header 6, a shaft seal electric heater 7, a shaft seal electric heater front electric valve 8, a shaft seal electric heater bypass electric valve 9, a shaft seal electric heater bypass electric valve 10, a shaft seal electric heater main path hydrophobic pneumatic valve 11, a shaft seal electric heater bypass hydrophobic pneumatic valve 11, a shaft seal electric valve 12, an auxiliary steam supply shaft seal electric valve 13, a shaft seal regulating valve 14, a shaft seal auxiliary steam supply shaft seal bypass electric valve 14, a shaft seal main path hydrophobic pneumatic valve 15, a shaft seal steam header to medium and low pressure communicating pipe electric valve 16, a shaft seal leakage steam to medium and low pressure communicating pipe electric valve 17, a non-return valve 18, a shaft seal steam header to medium and low pressure communicating pipe electric valve 19, a shaft seal electric heater 20, a temperature reducing water electric valve 21, a shaft seal electric heater regulating valve 22, a shaft seal steam header electric valve 23, a shaft seal electric heater bypass electric valve 24, a shaft seal electric valve 25, a shaft seal electric valve to low pressure, a low pressure heater electric valve 26, an auxiliary steam header pipe, a low pressure refrigerant pipe 29, a low pressure refrigerant pipe, a low pressure refrigerant heater, and a low pressure refrigerant pipe 31, a low pressure refrigerant heater, and a low pressure refrigerant heater.
Temperature measurements T 1、T2、T3、T4、T5 and T 6, pressure measurements P 1、P2 and P 3.
Detailed Description
The invention is described in further detail below with reference to the accompanying drawings.
Referring to fig. 1, the shaft seal system of the ultra-supercritical unit comprises an auxiliary steam header 6, and an ultra-high pressure cylinder 1, a high pressure cylinder 2, a medium pressure cylinder 3, a low pressure cylinder A4 and a low pressure cylinder B5 which are sequentially connected. The steam inlet sides of the ultrahigh pressure cylinder 1, the high pressure cylinder 2, the medium pressure cylinder 3 and the low pressure cylinders 4 and 5 are respectively supplied with steam by a main shaft seal steam pipe, the main shaft seal steam pipe is provided with a pressure measuring point P 1 and two temperature measuring points T 1、T2, after the sealing of a shaft seal cavity is completed, residual steam enters the main shaft seal steam return pipes through steam return pipes, each steam return pipe is provided with a manual steam return regulating valve, and the main shaft seal steam return pipe goes to the shaft seal heater 32. The shaft seal steam main pipe is provided with a drain pipeline, a drain pneumatic valve of the shaft seal steam main pipe is arranged on the drain pipeline, and drain water is sent to a drain header 30 of the condenser body.
Shaft seal leakage steam at two ends of the ultrahigh pressure cylinder 1 is led out through a pipeline and is connected with an exhaust pipeline of the ultrahigh pressure cylinder, and a check valve 17 is arranged on the pipeline; shaft seal leakage steam at two ends of the high-pressure cylinder 2 is led out through a pipeline and is connected with a middle-low pressure communicating pipe, a shaft seal steam main pipe to a middle-low pressure communicating pipe electric valve 18 is arranged on the pipeline, a drainage pipeline is arranged in front of the shaft seal steam main pipe to the middle-low pressure communicating pipe electric valve 18, a pneumatic valve 19 is arranged on the drainage pipeline, and drainage is carried out to a condenser body drainage header 30. The temperature measuring point T 4、T5 is arranged on the pipelines of the high-pressure cylinder exhaust pipeline and the medium-low pressure communicating pipe through which the shaft seal leaks steam.
The auxiliary steam header 6 is provided with steam sources respectively by an adjacent auxiliary steam header 26 and secondary reheating cold section steam 27. The auxiliary steam header 6 is provided with a temperature measuring point T 6 and a pressure measuring point P 3, and steam at the outlet of the auxiliary steam header 6 is connected with a main pipe of the shaft seal steam through the shaft seal electric heater 7, the auxiliary steam supply shaft seal electric valve 12 and the auxiliary steam supply shaft seal regulating valve 13 in sequence. The shaft seal electric heater 7 is provided with a parallel bypass, a shaft seal electric heater bypass electric valve 9 is arranged on the bypass, and a shaft seal electric heater front electric valve 8 is arranged in front of the shaft seal electric heater 7. The auxiliary steam supply shaft seal pipeline is provided with a parallel bypass, and the bypass is provided with an auxiliary steam supply shaft seal bypass electric valve 14. The main path and the bypass of the shaft seal electric heater and the main path and the bypass drain of the auxiliary steam supply shaft seal pipeline are both connected to the drain header of the condenser body, and the drain pipeline is provided with a pneumatic valve. A temperature measuring point T 3 and a pressure measuring point P 2 are arranged in front of the auxiliary steam supply shaft seal electric valve 12.
The seal steam main pipe is connected with the condenser 33 through the seal overflow adjusting valve 23 and the seal overflow to low-pressure heater electric valve 24, and meanwhile, the seal steam main pipe is connected with the low-pressure heater 34 through the seal overflow adjusting valve 23 and the seal overflow to low-pressure heater electric valve 25.
The side of the shaft seal steam main pipe, which is close to the low-pressure cylinder, is provided with a path of temperature reduction water, the temperature reduction water is taken from condensed water, and the temperature reduction water is connected with the shaft seal steam main pipe through a temperature reduction water electric valve 20 and a temperature reduction water regulating valve 21.
The invention provides an operation method of a shaft seal system of an ultra-supercritical unit, which comprises the following steps:
a. In the starting stage of the unit, the auxiliary steam header 6 supplies steam from the adjacent auxiliary steam header, the front electric valve 8 of the shaft seal electric heater, the auxiliary steam supply shaft seal electric valve 12 and the auxiliary steam supply shaft seal regulating valve 13 are opened, and the shaft seal electric heater bypass electric valve 9 and the auxiliary steam supply shaft seal bypass electric valve 14 are closed. The front temperature measuring point T 3 and the pressure measuring point P 2 of the auxiliary steam supply shaft seal electric valve are closely monitored, and the shaft seal steam main pipe temperature measuring point T 1、T2 and the pressure measuring point P 1 are closely monitored, wherein the shaft seal electric heater 7 regulates the auxiliary steam temperature, and the auxiliary steam supply shaft seal regulating valve 13 controls the shaft seal steam main pipe pressure. Simultaneously opening a main shaft seal steam pipe drain pneumatic valve 22, and opening a main shaft seal electric heater main path drain pneumatic valve 10, a bypass shaft seal electric heater bypass drain pneumatic valve 11, an auxiliary steam supply shaft seal main path drain pneumatic valve 15 and an auxiliary steam supply shaft seal bypass drain pneumatic valve 16 on a main shaft seal electric heater pipeline main path and a bypass drain pipeline; closing the shaft seal overflow regulating valve 23, the shaft seal overflow to the condenser electric valve 24 and the shaft seal overflow to the low-pressure heater electric valve 25, closing the shaft seal steam main pipe to the medium-low pressure communicating pipe electric valve 18, and closing the temperature-reducing water electric valve 20 and the temperature-reducing water regulating valve 21;
b. When the unit is connected with the power grid and the load is continuously increased, as the secondary reheating cold-section steam is exhausted from the high-pressure cylinder 2, the metal temperature of the cylinder body can be better matched, the auxiliary steam header steam source is switched, and the adjacent auxiliary steam header provides the secondary reheating cold-section steam which is gradually switched. Meanwhile, the shaft seal system is gradually changed into a self-sealing state, the auxiliary steam supply shaft seal regulating valve 13 is gradually closed, when the auxiliary steam supply shaft seal regulating valve 13 is fully closed, the shaft seal overflow regulating valve 23 and the shaft seal overflow to the condenser electric valve 24 are opened, the shaft seal system is in the self-sealing state, the shaft seal steam overflows and then goes to the condenser, and the shaft seal overflow regulating valve 23 maintains the stability of the temperature and the pressure of the shaft seal steam main pipe. Closely paying attention to the pipeline temperature T 5 of the shaft seal steam leakage to the medium-low pressure communicating pipe, and gradually opening the shaft seal steam main pipe to the medium-low pressure communicating pipe electric valve 18 after the temperature meets the requirement. Simultaneously closing the main shaft seal steam pipe drain pneumatic valve 22, and closing pneumatic valves on the main shaft seal electric heater pipeline main path and the bypass drain pipeline of the auxiliary steam supply shaft seal pipeline;
c. When the unit load is stable or in a high-load running state, the temperature T 2 is displayed at the temperature measuring point of the low-pressure cylinder side sealing steam main pipe, the temperature-reducing water electric valve 20 is opened when the temperature is higher, and the opening degree of the temperature-reducing water regulating valve 21 is regulated to control the temperature of the low-pressure cylinder side sealing steam. When the unit regenerative system is put into operation, the shaft seal overflows to the low-pressure heater electric valve 25, and meanwhile, the shaft seal overflows to the condenser electric valve 24 is closed.
The invention provides some optimization and operation methods for the shaft seal system of the ultra-supercritical unit, which are applicable to the ultra-supercritical unit, but are not limited to the ultra-supercritical unit. All the above description illustrates the basic principles, main features and advantages of the present invention. The present invention is not limited by the above embodiments, which are merely illustrative of the principles of the present invention. The invention is subject to various changes and modifications in the actual design construction process, which are all within the scope of the invention as claimed.
Claims (2)
1. The operation method of the ultra-supercritical unit shaft seal system is characterized by comprising an auxiliary steam header, and an ultra-high pressure cylinder, a medium pressure cylinder, a low pressure cylinder A and a low pressure cylinder B which are sequentially connected;
the steam at the outlet of the auxiliary steam header is connected with a shaft seal steam master pipe, steam inlet sides of the ultrahigh pressure cylinder, the high pressure cylinder, the medium pressure cylinder, the low pressure cylinder A and the low pressure cylinder B are respectively supplied with steam by the shaft seal steam master pipe, the shaft seal steam master pipe is provided with a pressure measuring point P 1 and two temperature measuring points T 1、T2, after the sealing of the shaft seal cavity is completed, the residual steam enters a shaft seal steam return master pipe through steam return pipelines, each steam return pipeline is provided with a steam return manual regulating valve, and the shaft seal steam return master pipe steam is sent to a shaft seal heater;
shaft seal leakage steam at two ends of the ultrahigh pressure cylinder is led out through a pipeline and is connected with an exhaust pipeline of the ultrahigh pressure cylinder, and a check valve is arranged on the pipeline; shaft seal steam leakage at two ends of the high-pressure cylinder is led out through a pipeline and is connected with a middle-low pressure communicating pipe, a shaft seal steam main pipe to a middle-low pressure communicating pipe electric valve is arranged on the pipeline, a drainage pipeline is arranged in front of the shaft seal steam main pipe to the middle-low pressure communicating pipe electric valve, a shaft seal steam leakage to a middle-low pressure communicating pipe drainage pneumatic valve is arranged on the drainage pipeline, and drainage goes to a drainage header of a condenser body;
The shaft seal steam main pipe is provided with a path of temperature reduction water close to the low-pressure cylinder side, the temperature reduction water is taken from condensed water, and the temperature reduction water is connected with the shaft seal steam main pipe through a temperature reduction water electric valve and a temperature reduction water regulating valve;
The auxiliary steam header is provided with a temperature measuring point T 6 and a pressure measuring point P 3, and steam at the outlet of the auxiliary steam header is connected with a main pipe of the shaft seal steam through a shaft seal electric heater, an auxiliary steam supply shaft seal electric valve and an auxiliary steam supply shaft seal regulating valve in sequence;
The shaft seal electric heater is provided with a parallel bypass, a shaft seal electric heater bypass electric valve is arranged on the bypass, and a shaft seal electric heater front electric valve is arranged in front of the shaft seal electric heater; the auxiliary steam supply shaft seal pipeline is provided with a parallel bypass, and an auxiliary steam supply shaft seal bypass electric valve is arranged on the parallel bypass; the main path and the bypass of the shaft seal electric heater and the main path and the bypass drain of the auxiliary steam supply shaft seal pipeline are both led to the drain header of the condenser body, and the drain pipeline is provided with a pneumatic valve; setting a temperature measuring point T 3 and a pressure measuring point P 2 in front of the auxiliary steam supply shaft seal electric valve;
the shaft seal steam main pipe is connected with the condenser through the shaft seal overflow adjusting valve and the shaft seal overflow to the condenser electric valve, and meanwhile, the shaft seal steam main pipe is connected with the low-pressure heater through the shaft seal overflow adjusting valve and the shaft seal overflow to the low-pressure heater electric valve;
The shaft seal steam main pipe is provided with a drain pipeline, a drain pneumatic valve of the shaft seal steam main pipe is arranged on the drain pipeline, and drain water is sent to a drain header of the condenser body;
The shaft seal steam leakage high-pressure cylinder exhaust pipeline and the pipeline of the medium-low pressure communicating pipe are provided with temperature measuring points T 4、T5;
the method comprises the following steps:
a. In the starting stage of the unit, the auxiliary steam header supplies steam from the adjacent auxiliary steam header, a front electric valve of the shaft seal electric heater, an auxiliary steam supply shaft seal electric valve and an auxiliary steam supply shaft seal regulating valve are opened, and a shaft seal electric heater bypass electric valve and an auxiliary steam supply shaft seal bypass electric valve are closed; monitoring a front temperature measuring point T 3 and a pressure measuring point P 2 of an auxiliary steam supply shaft seal electric valve, and a shaft seal steam main pipe temperature measuring point T 1、T2 and a pressure measuring point P 1, wherein an auxiliary steam supply shaft seal electric heater regulates the auxiliary steam temperature, and an auxiliary steam supply shaft seal regulating valve controls the shaft seal steam main pipe pressure; simultaneously opening a main shaft seal steam pipe drainage pneumatic valve, and opening a main shaft seal electric heater main path drainage pneumatic valve, a bypass drainage pneumatic valve, an auxiliary steam supply shaft seal main path drainage pneumatic valve and an auxiliary steam supply shaft seal bypass drainage pneumatic valve on a main shaft seal electric heater main path and a bypass drainage pipeline of the auxiliary steam supply shaft seal pipeline; closing a shaft seal overflow regulating valve, a shaft seal overflow to a condenser electric valve and a shaft seal overflow to a low-pressure heater electric valve, closing a shaft seal steam main pipe to a medium-low pressure communicating pipe electric valve, and closing a desuperheating water electric valve and a desuperheating water regulating valve;
b. When the unit is connected with the power grid and the load is continuously increased, as the secondary reheating cold-section steam is exhausted from the high-pressure cylinder, the metal temperature of the cylinder body can be better matched, the auxiliary steam header steam source is switched, and the adjacent auxiliary steam header provides the secondary reheating cold-section steam which is gradually switched; meanwhile, the shaft seal system is gradually changed into a self-sealing state, the auxiliary steam supply shaft seal regulating valve is gradually closed, when the auxiliary steam supply shaft seal regulating valve is fully closed, the shaft seal overflow regulating valve and the shaft seal overflow to the condenser electric valve are opened, the shaft seal system is in the self-sealing state, the shaft seal steam overflows and then goes to the condenser, and the shaft seal overflow regulating valve maintains the stability of the temperature and the pressure of the main pipe of the shaft seal steam; regarding the pipeline temperature T 5 of the shaft seal steam leakage to the medium-low pressure communicating pipe, gradually opening the shaft seal steam main pipe to the medium-low pressure communicating pipe electric valve after the temperature meets the requirement, closing the shaft seal steam main pipe drainage pneumatic valve, and closing the shaft seal electric heater main path, the bypass and the pneumatic valves on the auxiliary steam supply shaft seal pipeline main path and the bypass drainage pipeline;
c. When the unit load is stable or in a high-load running state, the display temperature T 2 of a temperature measuring point of a low-pressure cylinder side sealing steam main pipe is closely monitored, when the temperature is higher, a temperature-reducing water electric valve is opened, the opening degree of the temperature-reducing water regulating valve is regulated to control the temperature of the low-pressure cylinder side sealing steam, and when a unit regenerative system is put into operation, a shaft seal is opened to overflow to a low-pressure heater electric valve, and meanwhile, the shaft seal is closed to overflow to a condenser electric valve.
2. The method of claim 1, wherein the auxiliary steam header is provided by an adjacent auxiliary steam header and a secondary reheat cold section steam supply auxiliary steam header.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210190540.5A CN114635758B (en) | 2022-02-28 | 2022-02-28 | Ultra-supercritical unit shaft seal system and operation method |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202210190540.5A CN114635758B (en) | 2022-02-28 | 2022-02-28 | Ultra-supercritical unit shaft seal system and operation method |
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| CN114635758A CN114635758A (en) | 2022-06-17 |
| CN114635758B true CN114635758B (en) | 2024-05-07 |
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Citations (11)
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| CN113833534A (en) * | 2021-10-18 | 2021-12-24 | 西安热工研究院有限公司 | Supercritical carbon dioxide turbine shaft seal air supply and leakage recovery system and method |
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| JP2010209858A (en) * | 2009-03-11 | 2010-09-24 | Toshiba Corp | Steam turbine device |
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| CN114635758A (en) | 2022-06-17 |
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