Steam Turbine | Equipment Knowledge Lecture 100 Questions

01. The condensing equipment mainly consists of condensers, circulating water pumps, extractors, condensing water pumps, etc.

Task

(1) Establish and maintain a high vacuum at the exhaust outlet of the steam turbine.

⑵ Condense the exhaust steam of the steam turbine into water, which is then pumped to the reheating heater by the condensation pump to become the feed water for the boiler. In addition, there is also a certain vacuum deoxygenation effect.

02. The function of condenser cooling water is to condense exhaust steam into water and absorb the heat released by the condensation of exhaust steam.

03. The function of the heater drain device is to reliably discharge the drain inside the heater and prevent steam from leaking out.

04. The function of the shaft seal heater is to recover the shaft seal leakage steam, heat the condensed water to reduce the shaft seal leakage steam and heat loss, and improve the environmental conditions of the workshop.

05. The function of the low-pressure heater condensate bypass is to prevent interruption of the main condensate when the heater malfunctions or one of the heaters is stopped.

06. The function of installing an exhaust valve on the heater: In order to prevent air from forming an air film on the surface of the copper tube, which increases the thermal resistance and seriously affects the heat transfer effect of the heater, thereby reducing the heat transfer efficiency, an exhaust valve is installed.

07. The function of setting water side protection device for high-pressure heater: When the high-pressure heater fails or the pipe ruptures, it can quickly cut off the water supply to the heater bundle, while ensuring the supply of water to the boiler.

08. The function of a deaerator is to remove oxygen and other gases from boiler feedwater, ensuring the quality of the feedwater.At the same time, it can also heat the water supply to increase its temperature.

09. The purpose of setting a water seal cylinder in the deaerator is to ensure that the deaerator does not experience accidents where full water flows into other equipment. Prevent overpressure in the deaerator.

10. The function of the deaerator water tank is to store feedwater, balance the difference between the amount of water supplied to the boiler by the feedwater pump and the amount of water sent to the deaerator by the condensate pump, and thus meet the needs of the boiler feedwater.

11. The function of the deaerator reboiler pipe is to facilitate the heating of the feedwater in the water tank and maintain the water temperature in the standby water tank before the unit is started. It is beneficial to improve the deoxygenation effect during normal operation.

12. Function of hydraulic check valve: Used to prevent liquid backflow in pipelines.

13. The function of a safety valve: a valve that ensures the safety of equipment.

14. The function of pipeline supports and hangers is to fix pipes and bear the weight of the pipeline itself, the fluid inside the pipeline, and the weight of insulation materials.

15. The function of the feedwater pump is to continuously supply the boiler with sufficient pressure, flow rate, and equivalent temperature of feedwater.

16. The function of the circulating water pump is mainly to provide cooling water to the condenser of the steam turbine, condense the exhaust steam of the steam turbine entering the condenser, and also provide cooling water to the oil cooler, generator cooler, etc.

17. The function of the condensate pump air pipe is to discharge the accumulated air inside the pump.

18. The function of the temperature and pressure reducer is to compensate for the peak shaving of thermal heating in our factory.

19. Function of temperature and pressure reduction device:

In the external heating system, it is used to supplement the insufficient steam extraction of the steam turbine and can also be used as a backup steam source.

When the unit is started, stopped or malfunctions, it can play a role in regulation and protection.

⑶ Can be used as a low-pressure steam source for factory use.

⑷ Used for recovering the exhaust steam from boiler ignition.

20. The function of a steam turbine is a rotary prime mover that uses steam with a certain temperature and pressure as a medium to convert thermal energy into mechanical energy.

21. Function of cylinder: Separate the flow passage of the steam turbine from the atmosphere to form a closed steam chamber for converting steam heat energy into mechanical energy.

22. Function of steam seal: Reduce steam leakage from the cylinder and prevent external air from leaking into the cylinder.

23. Function of exhaust hood: Pour the steam discharged from the last stage moving blades of the steam turbine into the condenser.

24. The function of the exhaust cylinder water spray device is to prevent the deformation of the cylinder caused by excessive exhaust temperature, which can damage the consistency of the centerline of the dynamic and static parts of the turbine and cause unit vibration or other accidents.

25. Function of the upper exhaust valve of the low-pressure cylinder: In case of an accident, if the pressure inside the low-pressure cylinder exceeds atmospheric pressure, it will automatically open to exhaust steam to the air to prevent damage to the low-pressure cylinder, condenser, low-pressure section rotor, etc. due to overpressure.

26. Function of impeller: Used to install blades and transmit the torque generated by the steam flow force on the blade cascade to the main shaft.

The function of the balance hole on the impeller is to reduce the steam pressure difference on both sides of the impeller and minimize the excessive axial force generated by the rotor.

28. Function of blade root: Tighten the moving blade to prevent it from being pulled out of the wheel flange groove under the thrust and rotational centrifugal force of the steam flow.

29. Function of the sliding pin system:

⑴ Ensure that the cylinder can expand freely to avoid deformation caused by excessive stress.

⑵ Keep the final cause of the cylinder and rotor consistent to avoid center changes caused by body expansion, which may cause vibration or friction between the dynamic and static parts of the unit.

⑶ Ensure that the axial and radial clearances between the stator and rotor meet the requirements.

30. Supporting bearings, also known as radial bearings or main bearings, are used to support the weight of the rotor and the centrifugal force caused by rotor mass imbalance, and to determine the radial position of the rotor so that its center is aligned with the center of the cylinder.

31. The function of thrust bearings is to bear the axial force exerted by steam on the rotor, determine the axial position of the rotor, and maintain a certain axial clearance between the rotor and the stator.

32. The function of the turning device is to continuously rotate the rotor at a certain speed before and after the turbine starts and stops, in order to ensure uniform heating and cooling of the rotor and prevent bending of the main shaft.

33. The function of the steam turbine control system is to adjust the power of the steam turbine in a timely manner when the external load changes, in order to meet the needs of users with changes in electricity consumption, while ensuring that the working speed of the steam turbine generator set is within the normal allowable range.

34. The function of synchronizers: to change the speed of the turbine during single machine operation, and to change the power of the unit during parallel operation.

35. The function of the steam turbine regulation and protection system: In the event of a malfunction or failure of the steam turbine regulation system, it can act promptly, shut down quickly, and prevent the expansion of accidents and equipment damage.

The function of the automatic main steam valve is to quickly cut off the inlet steam of the turbine and shut it down after the protection device of the turbine is activated.

37. Function of the emergency safety device: After the emergency safety device is activated, it will release the secondary pulsating oil pressure of the regulating valve and the safety oil pressure of the main valve, causing the main valve and the speed regulating valve to quickly close.

38. Additional overspeed protection function: If the emergency safety device fails and the speed of the unit rises to 113% -114% of the rated speed, the auxiliary overspeed protection will activate, causing the emergency safety device to operate and shut down.

39. Function of axial displacement protection: When the axial displacement of the steam turbine reaches a certain value, the protection will activate and shut down,.

40. The function of low lubricating oil pressure protection: The low oil pressure protection device sends out alarm signals in sequence according to the degree of decrease in oil pressure, and links the auxiliary oil pump to shut down and operate the turning gear.

The function of low vacuum protection device: When the vacuum is lower than the normal value, the low vacuum protection device sends an alarm signal.

42. The function of the main oil tank: In addition to storing oil, it also plays a role in separating water, sediment, and bubbles in the oil system.

The function of the oil cooler is to cool the lubricating oil for the bearings of the steam turbine generator unit.

44. Principle and function of oil injector: When the pressure oil is sprayed out at high speed through the oil nozzle, a vacuum is formed at the nozzle outlet. The oil in the oil tank is carried into the diffusion pipe through the filter screen by the free jet suction effect, and then discharged at a certain pressure after deceleration and pressure increase. Improve the reliability of the main oil pump operation.

45. The function of the air cooler is to ensure that the generator operates normally within the allowable temperature range.

46. The function of a steam turbine nozzle is to convert the thermal energy of steam into kinetic energy, that is, to expand, reduce pressure and increase speed of steam, and spray it out in a certain direction to push the moving blades and do work.

47. The function of setting a hot water well in the condenser is to collect condensed water, which is beneficial for the normal operation of the condensate pump.

48. The function of the condenser is to continuously extract air and other non condensable gases from the condenser to maintain its vacuum.

The function of the water jet pump is to provide a certain pressure supply of water to the water jet steam extractor.

50. The function of a pressure regulator in a steam turbine is to regulate the supply steam pressure within a certain range of variation.

51. The function of the heater is to use steam that has done some work in the turbine to draw it to the heater to heat the feedwater, increase the feedwater temperature, reduce the amount of steam discharged from the turbine to the condenser, reduce cold source loss, and improve the circulation efficiency of the thermal system.

52. Function of the pressure equalization box: Adjust the steam supply pressure of the steam seal and recover residual steam.

53. Function of high-pressure hydraulic engine: Control the opening of the speed regulating valve, thereby controlling the steam inlet of the turbine.

54. Function of medium pressure hydraulic engine: Control the opening of the rotating partition, thereby controlling the external steam supply pressure and flow rate.

55. Function of bypass system:

⑴ Ensure the minimum load evaporation capacity of the boiler

⑵ Protect the reheater

⑶ Accelerate startup speed and improve startup conditions

The function of boiler safety valve

⑸ Recycling working fluid and some heat to reduce exhaust noise

Ensure the quality of steam.

56. The function of condensing equipment is to increase the ideal enthalpy drop of steam in the turbine and improve the circulating thermal efficiency of the unit. Condense the exhaust steam into water to recover the working fluid and send it back to the boiler as feedwater.

57. The function of a high-pressure heater is to use steam that has done some work in the steam turbine to heat the boiler feedwater, increase the feedwater temperature, reduce the boiler's heat load, and improve the thermal economic benefits of the thermal power plant.

58. The function of the low-pressure heater is to use steam or seal leakage that has done partial work in the turbine to heat the main condensate water, recover heat and working fluid.

The function of a check valve is to restrict the direction of fluid flow and prevent liquid from flowing in the opposite direction.

60. Pressure reducing valve: Maintain the supply steam pressure within the specified range.

61. Water injection tank: Provide sufficient water for the water injection pump.

62. Cooling tower: Cooling circulating water.

63. The functions of the water distribution tank and splash plate in the cooling tower are to continuously spray water to increase the contact area with the air and improve the cooling effect.

64. Variable speed steam valve: used for impulse starting and controlling the inlet steam flow.

65. Bypass valve for electric main gate valve: used for secondary pipe warming and turbine start-up.

66. Condensation pump: Send the condensed water to the deaerator in a timely manner.

67. Air valve of condensate pump: Ensure that the pressure at the inlet of the condensate pump is equal to that inside the condenser, to prevent gas from entering the inlet and causing water accidents.

68. Soft water replenishment valve: Before starting the condensate pump, inject softened water into the condenser to maintain a suitable water level in the hot water well.

69. Recirculation valve: Maintain the water level in the condenser hot water well.

70. Spray valve: Reduce the temperature of the rear cylinder.

71. Oil filter: Clean impurities from the oil in a timely manner to ensure the safe operation of the unit.

72. Recirculation pipe of water supply pump: to prevent vaporization of water in the water supply pump when the water supply pump is unloaded or under low load.

73. The deaerator is equipped with steam and water balance pipes on the steam side and water measurement to ensure that the pressure and water level of the deaerator running in parallel are consistent.

74. Turbine oil:

⑴ Lubricate the bearings and other rotating parts of the steam turbine generator, and remove the heat generated by friction, as well as the heat transferred from high-temperature steam to various parts of the steam turbine.

⑵ Tools for the turbine speed control system and the transmission of various hydraulic control valves.

75. Oil tank range hood: Exhaust gas and water vapor from the oil and establish negative pressure.

76. Lower limit stroke of synchronizer: In order to ensure the safety of the unit, the speed regulating valve can be quickly closed when the turbine suddenly loses load at low cycle rates.

77. Upper limit of synchronizer: In order to prevent the synchronizer opening from exceeding the normal value due to changes in steam parameters during operation.

78. Lower limit of synchronizer: Ensure that the unit can reliably perform parallel or disconnection when the power cycle rate decreases. 79. Upper and lower stroke of hydraulic servo motor: Ensure that the speed regulating valve is fully open or fully closed.

80. Boiler discharge expansion vessel: The wastewater inside the boiler is discharged into the expansion vessel to increase the volume, reduce the pressure, and vaporize some of the discharged wastewater, thereby recovering some water and heat.

81. High and low pressure oil connection valve in the oil system: When starting the unit, first start the low pressure oil pump through this valve, slowly fill the entire system with oil and drive the air to avoid causing pipeline vibration or speed control system jumping phenomenon

82. Centrifugal oil pump oil supply system:

⑴ Supply oil, lubricate and cool the bearings of the unit.

⑵ Provide stable and sufficient pressure oil for the speed control system and protective devices.

Provide lubricating oil for transmission mechanisms such as gears.

83. AC and DC lubricating oil pump: When the turbine malfunctions and the main oil pump cannot supply lubricating oil, it supplies oil to the lubrication system and turning oil.

84. Overpressure valve (overflow valve) in the lubricating oil system: Adjust the lubricating oil pressure.

85. High and low pressure drain expansion tank: Recover the drain from the cylinder and extraction pipeline to reduce the temperature difference between the upper and lower parts of the cylinder.

86. Accident throttle release: used to release oil from the fuel tank when the oil system catches fire, reducing losses.

87. Drain door for condensate water: discharge unqualified condensate water to ensure that qualified water enters the boiler.

88. Vacuum breaking door: used for emergency shutdown and rapid shutdown when the critical speed is exceeded, and to prevent damage caused by unit resonance.

89. Extraction check valve solenoid valve: controls the hydraulic check valve on the extraction pipeline. Purpose: To cut off the extraction steam and prevent the backflow of steam and liquid in the pipeline from causing water impact and damaging the steam turbine.

90. Magnetic circuit breaker throttle: composed of an electromagnet and an electromagnetic controlled throttle part. When the electromagnet is energized, the throttle piston moves downward, releasing the safety oil and establishing the emergency oil to close all valves.

91. Function of partition sleeve: It is used to install and fix partitions.

92. Function of turbine oil system:

① Supply oil to each bearing of the unit for lubrication and cooling of the bearings.

② Provide stable and sufficient pressure oil for the supply regulation system and protective devices.

③ Supply lubricating oil for various transmission mechanisms.

93. High pressure overpressure valve (pressure reducing valve): It adjusts the oil pressure entering the lubricating oil system through the pressure reducing valve when the lubricating oil from the main oil pump of the unit is supplied through the pressure reducing valve.

94. Low pressure and overpressure valve (safety valve): When the lubricating oil pressure is too high, the overpressure valve operates to discharge a portion of the oil to the oil tank, ensuring that the lubricating oil pressure is constant.

95. Function of the rotor: It bears the rotational force of steam on all working blades and drives the rotation of the generator rotor, main oil pump, and governor.

96. The function of the main oil pump is to power the oil system, continuously delivering oil to the lubricating oil and regulating oil system during normal operation.

97. Function of steam driven oil pump or high-pressure electric oil pump (speed regulating oil pump): Used to supply power oil and lubricating oil when the main oil pump does not work properly during the start-up or shutdown of the steam turbine. It is also used for static characteristic test of regulating system after shutdown.

98. Function of AC oil pump and DC oil pump: Generally used to supply lubricating oil to the turbine during turbine turning or accident situations.

99. Function of oil filter: Installed on lubricating oil and speed regulating oil pipelines, it mainly prevents impurities in the oil from entering the bearings and regulating oil system.

100. Functions of each component mechanism in the turbine control system:

① Speed sensing mechanism: It senses changes in the speed of the steam turbine and converts them into signals of displacement or oil pressure changes, which are then sent to the transmission amplification mechanism.

② Transmission amplification mechanism: amplifies the speed, senses the output signal of the mechanism, and transmits it to the actuator.

③ Execution mechanism: It usually consists of two parts: the regulating valve and the transmission mechanism. Based on the output signal of the transmission amplification mechanism, it changes the steam intake of the turbine.

④ Feedback device: In order to maintain stable regulation, the regulation system must be equipped with a feedback device that allows the output signal of a certain mechanism to adjust the input signal in reverse, so as to make the regulation process stable.