1、 Steam Turbine Specialty

1. The target cylinder temperature for sliding parameter shutdown is 400 ℃, and the rate of decrease in main and reheat steam temperature should not exceed 1.5 ℃/min. The rate of decrease in high and intermediate pressure cylinder metal temperature should not exceed 1.0 ℃. The rate of decrease in main steam pressure shall not exceed 0.3MPa/min. Lower the steam temperature first, then lower the steam pressure, and slide down alternately in sections. There should be sufficient dwell time at each stage. Every time the main steam temperature or load is lowered, the temperature should be further reduced after the reheated steam temperature has decreased.

2. During the sliding stop process, strict precautions should be taken to prevent water hammer in the steam turbine. Before stopping, a comprehensive inspection should be carried out to ensure that all manual drain valves are open and to control the superheat of the main and reheat steam to not be lower than 80 ℃. Pay close attention to the rate of decrease in steam temperature and cylinder wall temperature. If the steam temperature drops sharply by 50 ℃ within 10 minutes, the brake should be tripped and the machine should be stopped.

3. During the sliding parameter shutdown process, attention should be paid to adjusting the temperature deviation of the main and reheated steam to be less than 10 ℃, and ensuring that the main and reheated steam have a degree of superheat of 80 ℃ or above. Every time the main steam temperature or load is reduced by one level, the temperature should be lowered again after the reheated steam temperature has dropped, and there should be no rebound in temperature or pressure reduction.

4. When switching between main and bypass water supply, it is necessary to prevent significant fluctuations in water supply flow.

5. During the sliding stop process, major operations such as stopping grinding, stopping the feedwater pump, stopping the fan, etc. should be carried out separately and stabilized for 15-30 minutes after each operation is completed before continuing.

6. Closely monitor the temperature of the main and reheated steam to ensure a superheat of 80 ℃, and pay attention to monitoring the lower limit of TSE margin of the high-pressure main steam valve, regulating valve, rotor, cylinder body, and intermediate pressure main steam valve and rotor to be greater than 3 ℃. Control the metal temperature drop rate of the high and medium pressure cylinders and the temperature difference between the upper and lower cylinders within the TSE temperature margin control limit. Monitor and analyze the main steam valve chamber, high and medium pressure cylinder temperatures, and the metal temperature drop rate displayed by TSI at each point of the turbine, which should be normal and without any rebound phenomenon.

7. The unit load is around 240MW, and the electric feedwater pump is started as a backup.

8. During the sliding parameter shutdown process, it is strictly prohibited to conduct turbine overspeed tests.

9. During the sliding stop process, when the bypass is in a hot standby state, pay attention to monitoring the pressure and temperature changes after the high and low bypass.

10. During the sliding stop process, pay attention to monitoring the switching of the shaft seal steam source, adjust the shaft seal steam pressure and temperature in a timely manner, and control the difference between the shaft seal steam temperature and the rotor metal temperature within the allowable value. Prevent water ingress accidents in the steam turbine caused by switching steam sources.

11. After the shutdown speed of the unit is zero two hours, prepare to remove the shaft seal and vacuum system, and keep the shaft fan running. After the shaft seal system is shut down, immediately fully open the shaft seal overflow control valve and bypass manual valve. Open the hydrophobic expansion vessel and water curtain to spray water. Keep the lubricating oil purification device running during the shutdown period.

12. Monitor parameters such as unit vibration, axial displacement, tile temperature, cylinder expansion, vibration, upper and lower cylinder temperature, closely monitor the metal temperature and return oil temperature of the thrust tile block, and immediately trip and shut down if parameters exceed the limit. Record the metal temperature value and relevant parameters of the turbine body every hour after shutdown.

2、 Boiler major

1. Notify the fuel profession to reasonably control the coal loading of each coal bin, and control the C and F coal bins at 1/2 coal level according to the shutdown time. When the unit shutdown time exceeds 7 days, the raw coal hopper should be burned out.

2. When the pulverization system is shut down, the coal powder should be evacuated and the coal conveyor belt should be emptied to prevent self ignition of accumulated powder.

3. Strengthen boiler combustion and furnace pressure adjustment to prevent boiler fire extinguishing. After receiving the shutdown command, test run A mill plasma and D layer oil gun normally, and put 300MW load into plasma stable combustion.

4. When the load of the unit is greater than 400MW, for each heating surface (including the air preheater) SCR、 Perform a comprehensive soot blowing on the low-temperature economizer. Strengthen the monitoring of various temperatures and furnace pressures in the tail flue of the boiler during low load periods and plasma operation periods to prevent secondary combustion in the tail flue; Continuous soot blowing is applied to the air preheater, and the pressure after on-site soot blowing is above 0.8MPa.

5. Strengthen the monitoring of the wall temperature of each heating surface of the boiler during the dry wet transition and low load period to prevent overheating of the heating surface. Before the boiler is converted to a wet state, confirm that the warm pipe system is ready for use and that the boiler drain pump has been tested and started normally.

6. The boiler operates in a wet state, and after valve 361 is opened, the heating pipe and valve system should be promptly shut down.

7. During the shutdown process, control the temperature drop rate of the main and reheated steam not to exceed 1.5 ℃/min; There should be no rebound phenomenon in cooling and pressure reduction. Pay attention to the temperature deviation on both sides of the main steam and reheated steam during load reduction, which should not exceed 15 ℃, and the superheat degree of the main steam should be greater than 50 ℃.

8. Strengthen the monitoring and adjustment of feedwater and main reheat steam temperature to prevent significant fluctuations in steam temperature, resulting in overheating and large fluctuations.

9. After MFT of the boiler, ensure that the air volume is at least 30% for ventilation and blowing for 5 minutes; Then close each air damper and seal the furnace, and check that the boiler's manhole doors and fire observation holes are tightly closed.

10. When the outlet pressure of the superheater drops to 1.0MPa, prepare for boiler water discharge.

11. When the steam pressure at the outlet of the superheater drops to 1.0 MPa, open the drain valves of each part of the water-cooled wall and the economizer, drain water from the boiler, and perform waste heat drying maintenance after draining the boiler.

12. When the inlet flue gas temperature of the air preheater drops to 80 ℃, it is allowed to stop the operation of the air preheater.

13. When the furnace temperature drops to 45 ℃, the operation of the flame detection cooling fan can be stopped.

3、 Electrical Engineering

1. The shift supervisor should first ensure that the power supply of the diesel engine, AC/DC lubricating oil pump, sealing oil pump, top shaft oil pump, etc. is normal, the oil level in the fuel tank is checked and tested for good operation, and the battery, 220V/110V DC, and UPS system are checked for normal operation before issuing the sliding stop command. Otherwise, contact maintenance for timely handling before proceeding.

2. When the unit slips to a stop and the load reaches 180MW, a fast switching test of the plant power supply is carried out. Before the test, it is confirmed that the status of each backup switch is correct, and the fast switching device is in good condition and ready for backup. The test can only be carried out after the accident of the plant power supply switching and losing power is anticipated. After the test is completed, the plant power supply is switched and connected by the standby transformer.

3. After the unit starts sliding and stops, according to the load fluctuation situation, please ask the shift supervisor to pay attention to the automatic shutdown of the PSS device.

4. In non emergency situations, the generator set must be disconnected by reverse power through the program. It is forbidden to stop the generator set through the main transformer outlet switch at any time. Before disconnecting the generator set, pay attention to confirming that the neutral point grounding knife switch of the main transformer must be closed in place. Contact the second inspection to check the start and stop of the generator set, and the sudden voltage protection soft control must be in the input position before tripping and stopping. After disconnecting, confirm that the main switch of the generator outlet has indeed been disconnected, the three-phase outlet current has reached zero, and the unit speed begins to decrease. After confirming that the excitation system demagnetization switch is disconnected, report to the shift supervisor in a timely manner to shake out the main transformer outlet knife switch and the high and low voltage side switch of the plant transformer to the test position. The generator is turned into cold standby, and standby is not required under dispatch instructions. The generator set is in hot standby Should exceed 8 hours.

5. After the unit is shut down, unless the generator backwash is carried out, the internal cooling water equipment should be shut down according to the surrounding cold and warm environment, without causing condensation and insulation degradation of the generator, and with the arrangement of generator stator coil maintenance methods. Otherwise, the fixed cooling water system should be maintained or operated intermittently with qualified water quality, and the interruption should generally not exceed 72 hours.

6. The hydrogen replacement of the generator must ensure that the cooling water system is in good working condition, and the water temperature inside the generator is not lower than 25 degrees. Otherwise, the electric heating system will be put into operation. After the generator is shut down, the insulation monitoring device will randomly shut down. The hydrogen dryer can be turned on or off according to the humidity situation. During the replacement, both should be in a shutdown state and replaced together with the generator, and must not be isolated.

7. After the shutdown and disconnection of the busbar micro positive pressure device, the hot air maintenance status should be switched to operation as soon as possible.

8. After the unit is disconnected, the cooling fan of the main transformer will be stopped according to the weather conditions, and the oil temperature of the main transformer will not be lower than 25 degrees.

9. Operation tickets must be prepared for the start stop operation and state transition of the generator transformer group, and strictly implemented after passing the review, with ticket issuance operations.

4、 Chemistry major

1. 4 hours before shutdown, increase the concentration of the drug solution in the ammonia solution tank, increase the amount of ammonia added to the outlet of the condensate polishing treatment, and control the pH value of the inlet feedwater of the economizer to 9.5-9.6, corresponding to a conductivity of 9-11 μ s/cm. The unit stops running and exits fine processing.

2. After shutdown, ensure that the desalinated water tank is at full level and all four hydrogen tanks are filled to 2.6MPa.

3. Stop adding scale inhibitors and chlorine dioxide to the circulating water.

5、 Grey sulfur specialty

1） Ash removal system:

1. The pneumatic ash conveying system can only be stopped after the electrostatic precipitator is shut down and the ash conveying system must run without load until there is no ash accumulation in the ash hopper (conveying pressure less than 0.05MPa).

2. Before shutting down the ash hopper and ash silo gasification fan, the electric heating should be stopped first. The gasification fan can only be stopped when the temperature of the electric heating drops below 80 ℃.

3. After there is no accumulation of ash in the ash hopper, the ash hopper steam heating can be stopped, the ash hopper steam heating system should be isolated, and the drain valve should be opened to drain the accumulated water in the pipeline.

4. After shutdown, the ash silo will continue to release ash, emptying the ash storage in the silo and reducing the material level to zero. When the material level cannot reach zero, notify the maintenance personnel to check and confirm, calibrate the material level, and prevent residual ash from forming.

2） Slag removal system:

1. After the shutdown of the unit, the slag scraper will continue to operate. The slag scraper can only be stopped and the manual water replenishment valve of the water seal tank can be closed after receiving the order from the shift supervisor.

2. After the slag extractor is shut down, the slag bin continues to discharge slag, and the slag bin is emptied to check whether the material level indication is normal on site.

3. Transfer the stored water from the slag water tank to the coal settling tank through the slag water pump until it is emptied.

3） Electric dust removal system:

1. After the induced draft fan is shut down, the high-frequency power supply of electric fields 5, 4, 3, 2, and 1 will be shut down in sequence.

2. After the high-frequency power supply stops running, the anode cathode vibration continues to run for 2 hours.

4） Desulfurization system:

1. After the desulfurization system is shut down, open the low discharge of the desulfurization wastewater triple tank and drain all the stored water. If there is any sludge, notify maintenance for flushing.

2. After the desulfurization system is shut down, the gypsum silo continues to discharge materials and the material level is emptied.

3. Before shutdown, the limestone powder silo should be kept at a low level below 5 meters, and the gasification air should be continuously put into operation to prevent compaction.

4. Control the liquid level of the absorption tower below 8 meters before shutdown.

6、 Coal transportation major

1. Strengthen communication with the on duty supervisor before shutdown, and control the coal levels of each silo and raw coal bin in advance. Ensure that the coal level in the silo is 8-10 meters after shutdown. For silo # 1, which is a high calorific value coal (with a mixed calorific value of 5551 kcal), it can be appropriately reduced to 6-8 meters. Stop the machine and burn out the raw coal bunker as much as possible.

2. After the shutdown of the unit, strengthen the inspection of the silo inerting system, manually flush nitrogen into the silo once per shift (lock the gas layer), pay attention to the pressure changes in the nitrogen storage tank, and whether the nitrogen generator can work automatically when the nitrogen pressure is below 0.5mpa.

3. Strengthen the inspection and temperature measurement work of the coal yard, requiring multiple temperature measurements to be taken in the coal storage area of the coal yard three times per shift and recorded, with actual temperature measurement values included in the records.

4. Each class should carefully organize the study of measures to prevent spontaneous combustion of coal piles in the coal yard and prepare for accidents. The coal pusher is arranged to be on standby 24 hours a day and can arrive at the coal yard at any time to assist in handling the spontaneous combustion of raw coal.

5. During the shutdown period, the inspection and trial operation of various equipment along the coal conveying line should not be relaxed (the requirements for trial operation equipment are: the belt conveyor and bucket wheel machine should run for 10 minutes every day, and the coal plow and iron remover should be put into operation; the switch of the three-way baffle should be made, and the bucket wheel machine should return to its original position, pitch, and rotate once after walking 20 meters). If any abnormal situation is found, contact and handle it in a timely manner to ensure that the equipment is in a healthy standby state.

6. The fuel for coal pushing operations must be adequately prepared, and usage records and registrations must be kept.

7. Strengthen inspections and promptly report any abnormal situations to the on duty shift supervisor and fuel specialist.

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