Steam turbine, cold, warm & hot start up procedure











Turbine cold start up procedure

·         Check all turbine interlocks and protection of turbine.

·         Ensure MOT level normal.

·         Ensure DP across the Lube oil and Control oil filter is normal.

·         Start AOP and fill up the overhead tank up to normal level. Put the EOP in Auto mode.   Maintain the oil temperature within the range of 40 to 45 deg C by MOT heater on, if required. Cut off the MOT heater manually after getting 40 deg C. (Note: The minimum oil temperature for turbine start up is 25 deg C as per OEM manual). Keep stand by AOP in auto made.

·         After getting the above said temperature, start Vapour Extractor fan then start JOP. Ensure its normal discharge pressure i.e. 150 kg/cm2.

·         Put the TG on barring gear and at this speed, record vibrations & temperature at all bearing points.

·         Ensure TG runs on barring gear at least 1 hour prior to rolling. (Note: Prior to start up the steam turbine, the turning gear is operating for at least 25 minutes as per OEM manual).

  • Ensure hot well level normal i.e. 850 mmwc. Start CEP and put the system in recirculation mode. If required, make up the hot well level normal by make up
  • Control valve from surge tank. Put stand by CEP in auto mode. Keep Hot well control in auto mode.
  • Ensure cooling tower fore bay water level normal i.e. 60% and start MCW pump to circulate the cooling water through the condenser. Ensure l/L, O/L valve of condenser and l/L valve of cooling tower opened before MCW pump starts.
  • Adjust the I/L valve of cooling tower in such a way that, CW flow should not beyond the design value.
  • Open all the drain 100 % of main steam line and keep warm up vent in minimum position and open MSSV bypass valve fully at main steam pressure of 60 kg/cm2 & temperature of 350 deg C.
  • After ensured all condensate removed & colorless steam comes through drains, keep all the drains in crack position, then open main steam stop valve and close the by pass steam valve.
  • Charge the PRDS of Ejector and gland sealing PRDS line; ensure ejector pressure is of 10 kg/cm2 and temperature of 325 deg C. Adjust the HP & LP side gland sealing pressure at 1.1 ata. Maintain the sealing steam temperature of 393 deg C at HP side and temperature of 250 deg C at LP side.
  • Prior to pulling the vacuum, ensure vacuum breaker valve is closed. Then pull the vacuum through hugger ejector.
  • After getting vacuum -0.7 kg/cm2 through hugger ejector, take the main ejector into service and keep both the ejector in parallel and ensure the vacuum of - 0.93 kg/cm2 through running ejector, keep the main ejector in running and slowly close hogger ejector air line and then close the steam line after ensuring vacuum stable after STG synchronized only.
  • Ensure the Steam pressure at TG I/L is above 70 kg/cm2 (Alarm at 65 kg/cm2, Tripping at 52 kg/cm2), steam temperature at TG l/L is above 420 deg C (Alarm at 395 deg C, Tripping at 385 deg C), vacuum is above -0.7 kg/cm2 (Alarm at - 0.65 kg/cm2, Tripping at -0.5 kg/cm2). Acknowledge all the alarm in the annunciation panel/DCS and ensure all parameters are in healthy condition. Then reset the ESV of turbine through DCS to proceed for the rolling.
  • Ensure ESV opened & control valves are at zero position after reset the ESV. Give run command in Woodward 505E and observe the speeding should be carried out according to start up curve, respecting the preceding standstill  (soaking) time (thermal condition of turbine).
  • At every soaking period, record/check all the critical parameters with respect to speed as follows:

1.     Oil pressure & temperature

2.     Bearing metal temperature

3.     Main stream pressure & temperature

4.     Exhaust steam pressure & temperature

5.     Axial displacement

6.     Vibrations

What do you mean by turbo supervisory system???

  • Ensure barring gear motor is switched off in auto as per interlock
  •   If the oil temperature after oil cooler gets near to 48 deg C, adjust the cooling water O/L valve to maintain the oil temperature 49 deg C by keeping its I/L valve full open and ensure oil temperature should not below the 45 deg C.
  • If we prefer the rolling in manual, follow the start up curves and raise the speed as per start up curves and record above mentioned parameters at every soaking period Note: Cross the Critical Speed range as fast as possible.
  • Keep exhaust hood spray in auto mode. (Note: Do not allow exhaust steam temperature to exceed 105 deg C. Load Turbine or shut it off in case temperature keeps increasing.)
  • Start synchronizing by excitation on and voltage build up, match the DG voltage and frequency with generator voltage and frequency. When frequency and voltage matches within tolerable limit and synchroscope LED glows and allow to close the breaker. Close the breaker and increase the load on TG as per load curve (i.e. Approximately 2% of its rated load in order to avoid the activation of reverse power relay) up to the rated load by pushing the corresponding keys on the WOODWARD GOVERNOR
  • Adjust the Generator Air Cooler cooling water O/L valve to maintain the ‘Generator winding temperature by keeping its I/L valve full open.
  • Close all the main steam line drains and vents.
  • Start Remaining MCW pump and CT fan one by one to maintain the vacuum and exhaust temperature.
  • As per interlocks, after getting the steam flow of 60 TPH or more than 60 TPH at TG I/L, QC NRV of both bleeds of 22 ata & 9 ata respectively and control extraction of 3 ata will be reset.
  • Charge the Deaerator through control Extraction and ensure Deaerator pressure reaches at 1.5 kg/cm2 & temperature at 100 deg C at least.
  • Charge both the HP heaters and ensure Feed Water is charged through HP heaters prior to charge steam side.

TURBINE WARM START UP PROCEDURE

When after a clearly detected tripping the causes is eliminated or when the turbine is shutdown intentionally, observe the following for standstill’s longer than 5 minutes up to max. 8 hours

Refer the Warm Startup Curve given by OEM

  • Keep the live steam line up to the emergency stop valve pressurized and gland steam open unless turbine rests far longer than 60 minutes
  • Pre-warming the control valve block is not required
  • Open turbine drain(live steam)
  • The oil unit remains in full operation: the turbine oil should not be cooled below 45 deg C
  • Keep the turning gear in permanent operation
  • In case of no-uniform cooling-down process of turbine and rotor or drop out of turning gear (in this case immediately all isolation valves and steam to the labyrinths), slight distortion may arise, probably within the design clearances. This occurs especially with turbine arrangements where the turbine is exposed to an air draft.
  • In the case of a failure of turning gear motor or fall-out loss of electric power turn manually the turbine shaft by means of turning gear hand wheel each 5 minutes of must be turned manually at least 2 turns. If turning unexpectedly is not possible, at all circumstances do not apply undue force but let the turbine cool down.
  • Observe the instructions given & check for smooth action of the turbine at speed increase when starting again. Only a completely uniform warmed up turbine rotor is in straight condition so that further acceleration may take place without any risk.

                 SOP FOR TURBINE HOT START UP

 Refer the Hot Startup Curve given by OEM

  • Check the availability of import power and start DG set.
  • Open the warm up vent and chest drains.
  • Start AOP, MCW & CEP pumps.
  • Maintain the hot well level 50% through make up
  • Close the Vaccum breaker valve and restart the Vaccum pulling.
  • Keep the barring gear motor in auto.
  • Maintain the lube oil temperature 45 deg C.
  • Check the overhead tank healthy condition.
  • Check the availability of Vaccum, main steam pressure and temperature.
  • Inform to higher officials about all parameters in healthy condition for rolling.
  • Reset the turbine and give for rolling.
  • Check the vibrations, bearing temperature and any abnormalities.
  • After turbine attend 6800 RPM give clearance for synchronization.

 

 Read Boiler start up SOP

Read Steam turbine commissioning


 Turbine oil flushing procedure

 

 Vacuum pulling SOP


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BOILER COLD START UP PROCEDURE

  • Ensure DM water storage tank level normal and healthy condition of WTP for adequate water
  • Ensure availability of fuel quantity and power supply with DG backup.
  • Ensure trial runs (healthiness) of all equipment including fuel handling, ash handling / auxiliaries, motorized valves, actuators, control valves and PRDS controls are completed successfully.
  • Ensure that all interlocks / protection and controls are checked & taken in line.
  • Ensure expansion points are cleaned & tramps are in good condition.
  • Ensure Boiler manholes and flue gas path system manholes are boxed up.
  • Ensure availability of chemical dosing system and readiness of drum level gauge glass with illuminator assembly.
  • Ensure availability of cooling water, instrument air and service air.
  • Start the ACW pump, Instrument Air & Service Air Compressor.
  • Ensure all rotary air lock valves of modular bank hopper and economizer hopper gates are opened and then start RAVs.
  • Ensure healthiness of all dampers and keep them in open/close marked positions as and when required.
  • Open all air releases/vent valves in boiler drum and open super heater header drains and its vent valves.
  • Ensure all boiler bottom ring header drains, blow down valves and main steam stop valves including its bypass valves are closed.
  • Ensure Deaerator level normal. If level is low, make it normal through control valve by DM transfer pump.
  • Ensure oil level of bearings normal, minimum recirculation, balancing leak off valves & suction valves open, cooling water pressure normal.
  • Ensure sufficient suction pressure & suction differential pressure across strainer is normal.
  • Start BFP from control room. Ensure suction pressure, balancing pressure & discharge pressure normal. Bearing temperature & Vibrations normal. Ensure motor draws current normal & sound normal. Shut the BFP immediately if any abnormal condition and check thoroughly before restart.
  • Start water filling the boiler drum through 30 % control valve and maintain the drum level up to 30%.
  • Start the Ash handling plant prior to light up the Boiler. Then start all hoppers RAV.
  • Charge the hopper heaters, Insulator heaters of ESP prior to Boiler light up.
  • Start the purge air blower, collecting & emitting rapping motors prior to boiler light up.
  • Stack fire wood / baled bagasse inside the furnace for light up, put the fire and maintain the moderate temperature of furnace without fan by keeping suction damper & discharge damper of ID fan open.
  • Spread the fire throughout the furnace.
  • Raise the furnace temperature up to 150 °C to 250 °C.
  • After ensure the furnace temperature of 250 deg C, start ID, FD & SA. And maintain the furnace draft -2 to -10 mmwc, FD air discharge pressure by maintaining the rpm in the range of 10 to 15 %, SA air discharge pressure by maintaining the rpm in the range of 40 to 45 % with feedback of field supervisor.
  • Start screw feeder and then drum feeder including fuel feeding system (Fuel Handling System) and slowly rise the furnace temp by feeding fuel (maintaining the rpm of screw feeder and drum feeder in 20 % & 10 % respectively)
  • Maintain the steam drum level and if exceeds, maintain the level by giving IBD.
  • When drum pressure rises to 2-3 kg/cm2, close the drum air vents.
  • When drum pressure raises 5 kg/cm2, close all super heater vents, drains except secondary super heater outlet header vent & drain valves in crack opened condition. Open start up vent valve (5%) initially and increase the start up vent valve opening gradually according to steam pressure & temperature as per start up curve to allow the steam flow through SH.
  • At drum pressure of 5 kg/cm2, quickly give the blow down through IBD and furnace bottom ring header for 3 minutes.
  • Start HP & LP dosing and maintain recommended drum water parameters of boiler. Keep the CBD at minimum opening to maintain recommended residual PO4 & conductivity of drum water.
  • Check & record thermal expansion of boiler pressure parts and record the bearings temperature & vibrations of auxiliary equipment’s associated with Boiler.
  • Start & Stop the traveling grate as per requirement during light up and
  • Ensure sub merge belt conveyor for bottom ash disposal is in running condition.
  • Follow the cold start up curve and raise the pressure & temperature of Boiler as per the    curve. Start another ID, FD & SA fan and BFP as per requirement.
  • When boiler raises above pressure of 60 kg/cm2 & 350 deg C, charge the main steam line. Before charging the main steam line, open all the drains at 100 % and warm up vents at minimum opening and then open the MSSV bypass valve.
  • After ensured all condensate removed & colorless steam comes through drains, keep all the drains in crack position, then open main steam stop valve and close the bypass steam valve.
  • Charge the PRDS of pegging steam and charge the Deaerator. Maintain the PRDS pressure at 1.5 kg/cm2 and temperature at 120 deg C.
  • After getting the start permissive of ESP, charge the ESP.
  • Observe seal air pressure, conveying air vessel pressure of AHP is normal.

                   BOILER WARM START UP PROCEDURE

  • Start the DG set
  • Keep the boiler in hot box up.
  • Maintain the drum level accordingly.
  • After this give clearance to start the boiler.
  • Start the ash handling system accordingly
  • Ensure the de-aerator level.
  • Start ACW & compressor.
  • Start & regulate ID, FD & SA fans as per furnace draft.
  • Start fuel handling system.
  • Open start-up vent.
  • Start boiler feed pump.
  • Take fuel to boiler & Raise the pressure and temperature gradually warm start-up curve.
  • After reaching the pressure 25 kg/cm2 give blow down through ring headers.
  • After reaching the pressure 40 kg/cm2 and temperature 350deg c, open MSSV by pass valve and warm up the line up to TSSV.
  • Give clearance for vacuum pulling.
  • Slowly raise the pressure to 105 kg/cm2 and temperature to 540 deg C.

                 BOILER COLD START UP PROCEDURE

  • Check the availability of import power and start DG set.
  • Check the reason for tripping and after the analysis give the clearance to start the boiler.
  • Close the MSSV and keep boiler in hot box up.
  • Start the ACW and compressor.
  • Start the boilers feed pumps and maintain the drum level.
  • Start the ash handling system.
  • Observe seal air pressure, conveying air vessel pressure of AHP is normal.
  • Start ID, FD, SA fans as per the requirements.
  • Start the fuel feeding system and monitor the combustion feedback continuously.
  • After reaching the pressure 40 kg/cm2 and temperature 350deg c, open MSSV by pass valve and warm up the line up to TSSV.
  • Open the MSSV main valve.
  • Raise the pressure and temperature up to 105kg/cm2 & 545 deg C.
  • Give the clearance for rolling of the turbine.

 Read Steam turbine start up procedure

 Read Boiler Alkali Boil out procedure

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15-Emergencies in power plant operation

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