Station Black-out

IDENTIFICATION OF TOTAL AC FAILURE

Simultaneous happening of the following:

Unit tripping.

All HT, LT drives tripping.

400KV, 11KV, 3.3 KV Bus dead.

DC lights getting on.

DG set starting in auto.

1. Ensure starting of following equipments on auto otherwise start manually/from Local starting panels :

Main TG DC EOP.

DC Seal oil pump.

DC EOP of TDBFP – A & B.

DC Scanner fan.

DC JOP at TG speed of 510RPM

All Air heaters air motor.

Switch on DC lighting if does not come on auto.

2. Charge Cooling water of CC pumps

from Emergency overhead tank. (Open vent Valve in the cooling water return line to establish flow. Keep close watch on cavity temp of all CC pumps.)

3. Emergency bus charging

Emergency bus charging through DG incomer & BC closing on auto otherwise do it manually /from Local after ensuring tripping of both normal incoming breaker.(ensure no fault in relay)

If both DG sets does not come on auto, start it manually & charge emergency bus.

4. To avoid rupturing of LPT and TDBFPT diaphragms :-

Ensure opening of vacuum breaker. Give manual open command also.

Close Turbine & TDBFP A&B seal steam supply valves from UCB. Close manual isolating valves from Local.

Close all Mall drains.

Close all drain valves to SDFT & HP/LP Flash Tank.

Close MS – 1 & 2 valves.

Open MS strainer drains to UFT and CRH Pot drain to atmosphere.

Isolate CRH/Aux steam to Deareator

5. Ensure the following equipments running once Emergency bus gets charged through DG:

Main TG : AOP 2, AC seal oil pump 2,H2 side seal oil pump,AC JOP , Vapour extraction fan 2 of MOT and Gen. Brg.chamber fan 2

TDBFP A&B: AOP 2, JOP, Vapour extraction fan 2.

Boiler : AC Scanner air fan, AC lighting.(ELP)

Electric motors of all APHs. Air motors stops.

Stop DC equipments whose corresponding AC is started

6. Stop stand by DG set & monitor DG set diesel level, Winding, engine temperature

7. Ensure opening of barring gear valve at 210 RPM. Do hand barring if does not come on barring. Maintain Following parameter to avoid stalling of barring:-

Maintain TG lub oil temperature 55-60 degree

Maintain TG JOP pressure > 150 ksc & run both TG AOP

Maintain hotwell level -150 mm

8. Put TDBFP-A & B on barring

9. Run DG fire pump.(Monitor FW tank level)

10. Note down relay flags on :-

11KV / 3.3KV buses.

Generator protection panel.

Boiler/Turbine first up cause of tripping

11. Observe the following parameters closely :-

Hydrogen pr. from local gauge & UCB.

Purge Hydrogen by CO2 in case of problem in maintaining Seal oil DP.

12. Check 220 Volt, 24V and UPS charger came on load & monitor voltage.

13. Ensure following isolations after unit tripping:-

Ensure closing of HOTV / LOTV

Isolate SH / RH / HP bypass spray isolating valves

Isolate all oil guns

Isolate soot blowing steam line if charged

Switch off all ESP fields

Ensure closing of HP/IP stop & control valves

Ensure closing of all turbine extraction valves

Restoration of supply and normalization

Charging of 400kv buses and ST#3

Normalize 11KV station bus 3SA, Normalize Unit buses through UT/Station Bus. Normalize 3.3 KV switch gear UAA both sections.

Normalize Switchgears :USS,SSS,TMCC,BMCC,Service Building MCC,ESP MCC,Offsite Switch Gears (Charge all 3.3 KV / 415 V Switch gear independently)

Normalize Emergency Bus from USS:- Synchronize UES with USS and close I/C from USS. OR Charge dead bus by putting DG on manual and closing I/C from USS. Trip the DG breaker and stop DG Set.(While dead bus charging, first of all changeover all the running drives in EMCC)

Normalize supply of PT plant, DM Plant Fire pump house, CW MCC, SACW, ASH HANDLING MCCs, AC MCC,FOPH MCC etc.

Start DM make up pumps

Start electric fire water pump & stop DG fire pump

Start Raw water pump & start CLW pump for Forebay/OAC makeup. Start SACW and service water pumps.

Run Main Plant A/C System.

Prior to start 11KV equipments, take permission from Switchyard Control Room.This is to avoid overloading of station Transformer.

Start CW pumps (Before starting ensure discharge valves are closed and vent valves in condenser inlet / outlet ducts are open). Charge both passes of condenser.

Start ACW and ECW pumps.

Start Instrument and plant air compressor and maintain header pr 6 ksc

Start CEP

Start oil pump (LDO/HFO) & charge oil lines on the short recirculation.

Start MDBFP and fill the Boiler drum up to normal level.

Charge aux. PRDS (MSPRDS may also be opened slightly to maintain adequate seal steam temp otherwise open PRDS drains and seal steam drains

Normalize the system further for unit synchronization:

Start stator water pump

Start CF pumps & its vapour fan. Put recirculation pumps in service

Start LOPs of ID/FD/PA/MILLS/APH

Maintain hotwell, deareator & drum level

Maintain HFO pressure 16 ksc & temperature 120 degree

Take round of Boiler and TG area for any abnormal sound/ water /steam /oil leakages/any hammering

Start ID/FD fan & start purging

Put HFO in long recirculation and maintain HFO temperature >115 degree

Light up boiler with 04 LDO oil guns

Charge APH soot blowing from PRDS

Open CBD & Eco recirculation valve

Start vacuum pump & observe condenser vacuum

Charge TG & TDBFP gland sealing system at -0.2ksc

Open drains of MS/CRH/HRH/ Mall drains

Open drains before boiler stop valve

Charge MS lines

Charge HP/LP bypass valves

Raise boiler & turbine rolling parameters as per starting procedure

PROCEDURE FOR TAKING MAKE-UP IN TO THE SYSTEM

PROCEDURE FOR TAKING MAKE-UP IN TO THE SYSTEM

The tank level is to be normally maintained at approximately 220 mm . ( 255 mm HI alarm , 195 LO alarm ) .When ever the tank level drops to below 200 mm the PW system makeup to be taken up to 240 mm .

The approved committee must be informed before taking PW make up in to the system for any reason.

Always the make-up should be taken through Ion exchanger circuit only .

At a time, make-up quantity should not be more than 100 liters. However depending on the requirement thisquantity will vary.

Steps for taking Makeup :

Put DM make-up line to PW system under flushing up to the inlet valve by opening the drainvalve .

Isolate the ion Exchange circuit from the main PW system by closing both inlet and outlet valve.Ensure direct makeup is closed.

Stop alakaliser system & close the valve .

Stop Flushing of DM water after 2 hours .

Open the drain after fine filter in treatment circuit  & open the Makeup water valve  to establish flow through the ion exchanger circuit

Maintain a flushing flow rate of 1m³/hr through drain valve till conductivity after ion exchanger is 1µmho/cm .

Then get clearance from chemistry for taking makeup into system . Stop flushing by closing the drain valve .

Note down the Flow Integrator reading & SW tank level .

Take make-up by opening the ion exchanger circuit outlet valve slowly. Monitor the level in CCR as well as at local through the level gauge glass float & N2 pressure at 8.5 Mtr

If it is a normal running unit the quantity should not exceed 100 Litres at one go . If it is a shut down unit(Winding remains bypassed ) it is to be taken as per normal requirement i.e up to 300 mm in OH tank .

Precaution During Taking Makeup :-

Ensure that water does not get filled in the entire tank & enter in to purging gas line during filling oraddition of make up water.

After taking make-up, close the make-up valve. Line-up the dosing system i.e., open ion exchanger inlet valve fromPW pump discharge line. Adjust the flow in the ion exchanger circuit to 40 LPM ( 2.4 m3 /Hr )

Start Alaklyser circuit .

Nitrogen purging to be started immediately as per the following procedure from H2 filling room till O2 < 20ppb .

PROCEDURE FOR N2 PURGING AFTER SW MAKEUP

Preparatory work

After initial filling of the primary water circuit and following the addition of larger quantities of primary water (>100dm3 ( 100 Liter ) per month), the primary water tank should be purged with nitrogen to reduce the oxygen contentof the primary water.

During purging, O2 is extracted from the primary water and discharged to the atmosphere via the vent gas line.

Prerequisites for N2 purging:

The external primary water circuit was filled with water.

The primary water pumps must be available

A reliable nitrogen supply must be available.

The N2 pressure reducer was set to a gauge pressure of 0.5 bar

Steam Turbine - Protective Devices

Steam Turbine - Protective Devices

Over-speed Trip

Two Over-Speed trips MAY10 AA001 and 002 are provided to trip/shut down the turbine in the event of overspeed.

Each trip device consists of an eccentric bolt/striker fitted in the emergency governor shaft with its center of gravity displaced from the axis of rotation and held In position against centrifugal force by a spring up to an adjustable preset speed of 10 to 12 % above the normal turbine operating speed.

At the preset overspeed, centrifugal force overcomes the spring force and the eccentric bolt/striker flies outwards into its extended position.

In doing so it strikes the pawl which releases the piston of the overspeed trip release device KA01.

Through combined spring force and fluid pressure, the piston opens the auxiliary trip fluid circuit to the main trip valves MAX51 AA005 and MAX51AA006.

Thrust-Bearing Trip

Thrust bearing trips MAD12CY011/012/013 are tripped electrically in the event of excessive axial displacement of the turbine shaft.

Pressure Switch

Installed in the trip fluid circuit are two pressure switches MAX51CP011 and MAX51CP012

which bridge the longtime delayed relays of the reverse-power protection system in such a way that the generator is shut down by response of the short-time delayed relays as soon as it begins to motor.

The annunciation Turbine trip initiated is transmitted simultaneously to the control room.

Remote Solenoid Trip

Remote solenoid trip is activated via solenoid valves MAX52 AA001 and MAX52 AA002.

The remote solenoid trip may be initiated

1. manually from the control room by push button,

2. by the electrical low-vacuum trip or

3. the thrust bearing trip

4. or other protective devices.

Low-Vacuum Trip for Turbine Protection

An increase of pressure in the condenser causes the valve of low-vacuum trip MAG01 AA011 to move downwards from its upper position under the force of the pre-tensioned spring.

This action depressurizes the space below the right-hand valve.

The right-hand valve is moved into its lower position by a spring and thus opens the auxiliary trip fluid circuit.

Opening the auxiliary trip fluid circuit depressurizes the fluid below the differential pistons of main trip valves MAX51AA005 and MAX51AA006 and the differential pistons are activated by a spring.

This closes the control fluid inlet to the trip fluid circuit and at the same time opens the main trip fluid circuit to drain, causing the trip fluid pressure to drop and all stop and control valves of the turbine to close.

Limit switch MAG01CG011B signals to the control room that the low-vacuum trip is not in its normal operational position.

Limit switch MAG01 CG011C indicates in the control room that turbine trip has been initiated by the low- vacuum trip.

To make it possible to latch-in the trip devices and thus to build up trip fluid pressure for adjusting and testing the control loop or similar purposes when the turbine is shut down and no vacuum exists, the low- vacuum trip has an auxiliary piston which is loaded with primary oil pressure above the adjustable compression spring.

When the turbine is shut down there is no primary oil pressure and so the auxiliary piston is unable to tension the adjustable compression spring arranged above the diaphragm system.

The spring below the diaphragm system lifts the valve, closing the auxiliary trip fluid circuit so that the trip devices can be latched in.

As soon as the turbine is started up and brought up to speed, primary oil enters the space above the auxiliary piston, forcing in into its lower end position at a turbine speed far below rated speed.

Thus the low-vacuum trip is reset for initiation of turbine trip before the turbine has reached rated speed.

Solenoid Valves for Load Shedding Relay

Solenoid valves MAX45 AA001 and MAX46 AA011 are provided to prevent the turbine from reaching trip-out speed in the event of a sudden load rejection.

These solenoid valves are actuated by the load shedding relay if the rate of load drop relative to time exceeds a predetermined value.

Solenoid valve MAX45AA001 opens the IP secondary fluid circuit directly.

Solenoid valve MAX46 AA011 opens the auxiliary secondary fluid circuit.

Pilot valve KA07 of hydraulic converter MAX45BY011 moves upward and allows the control fluid to flow to the area below piston KA08 of the converter.

Piston KA08 moves to its upper end position, thereby depressurizing all secondary fluid circuits.

Since the reheat IP secondary fluid circuit opens directly, the IP control valves (which control the major portion of the power output) close without any appreciable delay.

A small delay is involved in closing all other control valves by depressurizing the auxiliary secondary fluid circuit, but his action is still performed before an increase in turbine speed causes the speed controller to respond.

At the same time, the extraction check valves, which are dependent on secondary fluid via extraction valve relay MAX51AA011, close.

After an adjustable interval, the solenoid valves are reclosed, permitting secondary fluid pressures corresponding to the reduced load to build up again.

Turbine Trip Gear

The trip fluid is taken from the control fluid  via main trip valve MAX51AA005 and MAX51AA006 and flows both to the secondary fluid circuits and to the stop valves MAA10+20AA001 and MAB10+20AA001.

The main trip valves serve to rapidly reduce the fluid pressure in the trip fluid circuit.

If the pressure below the differential piston of main trip valves MAX51 AA005 and MAX51AA006 drops below a preset adjustable value, the piston in each valve is forced downwards by the spring, opening the drain passage for the trip fluid and closing the control fluid inlet.

If the pressure in the trip fluid circuit drops below a predetermined value, spring loading separates the upper and lower pistons of main stop valves MAA10+20 AA001 and reheat stop valves MAB10+20 AA001, and all the stop valves close very rapidly.

At the same time, the control valves and extraction check valves also close, as the secondary fluid circuits are fed from the trip fluid circuit.

Thus on trip initiation, all turbine stop and control valves close.

Manual local Trip Method of Initiating Turbine Trip

Manual local initiation of turbine trip is performed by way of local trip valve MAX52 AA005.

The valve must be pressed downwards manually, thus opening the drain passage for the auxiliary trip fluid.

The two limit switches MAX52CG005C and MAX52 CG005E indicate in the control room that trip has been initiated locally by hand.

LRSB Schedule

LRSB Schedule
Day	Morning			Evening
Monday	105 , 106 , 109 , 110			123 , 124
Tuesday	105 , 106 , 111 , 112			107 ,108
Wednesday	105 , 106 , 113 , 114			117 ,118, 121 ,122
Thursday	105 ,106 , 109 , 110			107 ,108
Friday	105 , 106 ,115 , 116			119 ,120
Saturday	105 , 106 ,117 , 118			107 , 108
Sunday/ GH	******			******

BOILER & AUXILIARIES START-UP (COLD-START)

BOILER & AUXILIARIES START-UP (COLD-START)
INITIAL CONDITION:
Boiler is depressurised condition.
Boiler is filled up to the normal level.
All boiler auxiliaries are cleared for operation.
CC pumps cavities are filled.
LINE-UP:
The following systems/ equipments should be lined up and made ready for operation:
Aux. PRDS Steam system.
Fuel oil-handling system.
Instrument air system.
Plant air system.
Equipment cooling water system.
All three CC pumps: Cavity filling completed and discharge valves are kept open.
Both secondary and primary air heaters with associated dampers.
Both ID fans should be ready and lined up.
Both FD fans should be ready and lined up.
AC and DC scanner air fans.
SCAPH for primary and secondary air heaters.
Both PA fans should be ready and lined up.
Mills: Those required for full load operation should be made ready and which are not available should be isolated.
Coal feeders.
Both seal air fans.
Electrostatic precipitator.
Pent house pressurizing fan.
Soot blowing system – for air heaters.
Furnace temp. probes.
Water / steam sampling system.
The equipments readiness can be ensured by complying with the Recommissioning
checklists.
3.0 CHARGING OF SYSTEMS:
3.1 Charge aux. Steam to the boiler (from running unit or aux. Boiler). Ensure proper draining of the lines before charging. Aux. Steam for oil heating, oil lines tracing, atomizing steam, air heater, soot blowers and steam coil air heaters should be made available.
3.2 Start instrument air compressors and charge instrument air to boiler, turbine,auxiliaries and off-sites.
3.3 Start plant air compressors and charge plant air igniter cooling, air heater, air motors and other cooling/cleaning requirement.
3.4 Start equipment cooling water pumps and charge the coolers for all equipments.
3.5 Charge HF up to the burner front and keep it on long recirculation.
4.0 PRESTART CHECKS:
Fill the Boiler cold start-up checklist and get the deviations approved by the competent
authority.
5.0 START-UP:
The sequences of starting of the equipments are given below. For details refer to the
standard operating procedure of the individual equipment.
5.1 Start two CC pumps one by one and keep them in service. Check for the differential pressure and ensure that it is normal. Drum level has to be maintained high (about + 300 mm) before starting the pump and it should be maintained ‘Normal’ afterwards.
5.2 Start the secondary air heaters* one by one & keep the associated dampers open.
5.3 Start the primary air heaters one by one. Though it is not required as a purge permissive, it is better to keep them in service from the safety angle. Keep the gas outlet dampers closed, till air flow is established.
5.4 Start the first ID fan. Ensure that its suction & discharge dampers open to full. Also check for the closure of the suction / discharge damper / inlet vane of the other fan.
5.5 Gradually raise the IGV and then vane of the running fan and maintain a furnace draft of about –10mmwc.
5.6 Start the corresponding FD fan (if it is not available the other FD fan can be started). Ensure that the discharge damper of the running fan opens full and the blade pitch and discharge damper of the non-running fan closes full.
5.7 Gradually raise the load on the FD fan. Parallely control the IGV and vane of the running ID fan to maintain the furnace draft. (Ensure that the secondary air dampers are open and modulating). Raise the total air flow to more than 30% (630 tph), which is the purge requirement.
5.8 Put the wind box pressure control (aux. air dampers) in auto and maintain the desired wind box to furnace differential pressure.
5.9 Start the second ID fan. Ensure fuel opening of its suction and discharge damper.
5.10 Slowly raise the IGV and vane of the second ID fan and reduce those of the first ID fan to equalize the heading on both fans, always maintaining the furnace draft within limits.
5.11 Start the second FD fan. Ensure that its discharge damper opens fully.
5.12 Gradually raise the blade pitch of the second FD fan and reduce that of the first FD fan to equalise the loading on both fans maintaining the minimum air flow and normal furnace draft.
NOTE: If so desired, the second set of ID / FD fans can be started at a later stage (after
synchronization and auxiliary supply changeover) to reduce the auxiliary power
consumption and loading on station transformer. But keeping both the fans in service is
preferable from the operation flexibility point of view. It avoids tripping of the boiler on
protection in the event of outage of one fan and reduces the furnace disturbance at a later
stage while starting the second set of fans.
5.13 Put the furnace draft control in auto. However, the performance of the auto loop should be kept under observation during low load operation.
5.14 Start the AC scanner fan and keep it in service. Keep the other fan as auto standby. Ensure that the scanner air pressure is normal.
5.15 Charge the SCAPH of both FD fans. Regulate the steam flow to maintain the air heater cold end temp.
5.16 Close the HFO Trip Valve and Recirculation Valve (which were opened earlier for charging and warming up the oil lines – Refer Sec. 3.5). Open the Short Recirculation Valve.
5.17 After completing the above activities, ensure that the following Purge Permissives are satisfied and the ‘PURGE READY’ Light is ‘ON’:
1. All HFO nozzle valves are closed.
2. All mills are OFF.
3. No boiler trip.
4. All feeders are OFF.
5. All scanners sense ‘No Flame’.
6. All auxiliary air dampers are modulating.
7. Both PA fans are OFF.
8. All hot air gates are closed.
9. Air flow >30% and <40%.
10. HFO Trip valve is closed.
11. Wind box to furnace difference pressure is normal.
5.18 Ensure that the cold start-up checklist is completed in all respects and the deviations are noted.
BOILER LIGHT-UP:
5.19 Start the furnace purge cycle by depressing the ‘PUSH TO PURGE’ button. ‘PURGING’ light comes ‘ON’ and purging continues for 5 minutes (if the purge time is disturbed, it should be corrected).
5.20 If the purging is interrupted due to any reason (loss of one or more of the purge permissive), purging should be restarted.
5.21 On completion of purge ‘PURGE COMPLETE’ light becomes ‘ON’. MFT gets reset.
5.22 Open the HO Recirculation Valve and HO Trip Valve; close the Short Recirculation Valve.
5.23 Bring the HFO header pressure and temperature to normal value. Ensure that atomizing steam pressure is normal.
5.24 Ensure that Burner tilt is horizontal.
5.25 Select the oil burners to be fired. During cold start-up normally lower (AB) elevation oil burners are selected.
5.26 Give start command to the selected burner. It is preferable to start one burner at a time, by monitoring its performance at local. (Individual burner selection can be done by keeping its selector switch in Remote at local).
5.27 Check and ensure that the burner is firing properly. In case of poor flame or a leak, take out the burner immediately. Identify the cause and attend it.
5.28 After proving the first burner successfully select the next burner (preferably on the other side in the same elevation) and give start command. Ensure proper flame. Similarly all the four burners in the elevation (maximum) can be kept in service. Regulate the oil pressure.
5.29 Keep the furnace draft at normal values while cutting in oil burners.
5.30 Ensure that the auxiliary air dampers of the burners in service are open.
5.31 Check the chimney exit. If excessive black smoke is observed, adjust air flow.
5.32 Start Air preheater soot blowers. Check for any oil carry over with the help of oil carry over probe. Inspect the air heater through the inspection doors provided on the air side.
5.33 Maintain drum level within normal limits (+ 100mm). Keep economizer recirculation valve open when there is no feeding to the drum.
5.34 Monitor the boiler pressure increase and ensure that it is within allowable limits (It should not exceed a corresponding increase in saturation temp. of 100ºC/hr.).
5.35 At a drum pressure of 2kg/cm 2 close all SH vents and drains. Leave the start-up vents open.
5.36 Insert furnace temp. probe occasionally and ensure that the gas temp. is less than 540ºC.
5.37 Monitor the rate of increase of SH outlet temp. and ensure that it is within limits (less than 5ºC/min.).
5.38 Monitor the drum, SH and RH metal temp. and ensure that they are within limits. (Drum metal temp. raise should be within 2ºC/min.).
5.39 Start the dosing pumps and do chemical dosing as per Chemist’s advice. Open CBD as per the Chemist’s advice.
MAIN STEAM LINE CHARGING:
5.40 Do condenser vacuum pulling after making the associated system ready.
5.41 Ensure that MS, CRH and HRH line drains are open (turbine side) and system is ready for operation; turbine is on turning gear and stop/control valves are closed.
5.42 Ensure the readiness of HP/LP Bypass System.
5.43 When drum pressure reaches about 4 kg/cm 2 , start charging main steam line by gradually opening the bypass (warm up) valves of Boiler Stop Valves on both sides. {Ensure that the main valves are not in Auto. In auto the valves gets open command when the bypass valves are full open).
5.44 Open the Boiler Stop Valve Monitor the pressure rise of MS line bypass valves to full. Open HP Bypass warm-up valves to warm-up the CRH lines. Observe for any abnormality (like hammering etc.) in the system.
5.45 Open HP bypass valves partially and ensure that the pr. control valves, spray valves and the protection system is working properly.
5.46 Open HP bypass valves partially and ensure that the pr. control valves, spray valves and the protection system is working properly.
5.47 Monitor the pressure rise in the boiler. When the pressure exceeds 5kg/cm2, open Boiler Stop Valves and regulate HP Bypass Valves to control the pressure close start-up vents. Close HP Bypass worm-up valves.
5.48 Open LP Bypass Valves and keep it partially open at lower pressures. When the pressure improves control the LP Bypass Valve opening so as to maintain a pr. of about 12 kg/cm2 in the HRH.
5.49 When boiler pressure reaches 7kg/cm2, start the third CC pump and keep it in service.(NOTE: Pumps should not be started during intervals of rapid boiler water temp. change).
TURBINE ROLLING & SYNCHRONISING:
5.50 Raise the boiler parameters (by controlling the firing rate) as per the requirements of Turbine by following the allowable ramp rate.
5.51 At a main steam pressure of 15kg/cm2 and HRH pressure of 8-12 kg/cm2 reset the turbine (Refer Turbine start-up procedure).
5.52 At 50 kg/cm2 MS pressure, 12kg/cm2 HRH pressure and 350ºC MS/HRH temp. roll the turbine and synchronize the machine.
5.53 After taking block load, close HP/LP Bypass and keep it in auto with proper pressure set point.
5.54 Close CRH, HRH and MS drains. Ensure closing of MAL drains in auto.
5.55 Before the feed water flow to the boiler reaches the capacity of the low load line, one of the high capacity lines should be placed in service.
5.56 Economizer recirculation valves should be closed after establishing a constant feed water flow.
COAL FIRING:
5.57 Ensure that both ID / FD fans are in service and are equally loaded. Furnace draft control is put in auto.
5.58 Start the first PA fan. Ensure that its discharge damper opens in auto and the discharge damper of the other fan closes in auto.
5.59 Start the second PA fan. Ensure opening of its discharge damper. Load both the fans gradually and raise the PA header pressure to normal value. (PA fans should not be run without air flow for long duration)
5.60 Ensure that one of the seal air fans starts in auto. If not, keep it in service; keep the other fan as standby.
5.61 Open the gas dampers of the primary air heaters. Improve the primary air temperature.
5.62 Start the first mill (preferably bottom elevation) and keep it in service. Increase the loading gradually.
5.63 Keep the other mills in service as per the load requirement.
5.64 Gradually raise the steam parameters and unit load as per the start-up curves by observing TSE margins.