boiler inspection -daily

8/12/2019 Boiler Inspection -Daily

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Boiler inspection practicesBoiler inspection practices

Daily inspection aspects ofDaily inspection aspects of

AFBC boilersAFBC boilers


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Check for deviations in Feedwater & boiler waterquality.

Check the condensate return conductivity is normal.

Check condensate pH does not deviate from 8 to8.5. If the condensate pH is likely to be upset planfor a separate storage tank.

Look for iron oxide contamination in condensatereturn. In case of deviation take remedial action.

Check the DM water tank water pH is 8 to 8.5.

W TER QU LITYTER QU LITY


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Check saturated steam conductivity remains normalas before.

Check raw water turbidity due to rain and modifythe back washing cycle of filters.

Check appropriate PO4 levels are maintained as per

the boiler operating procedure.When there is a possibility of boiler stoppages,give blow down at all bottom most drains.

Do not practice intermittent blow down as it upsetsthe chemical concentrations.



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Blow down water shall not be reddish / whitish.

Reddish implies corroding boiler. Whitish water showsexcess chemical dosage. Ensure minimum hydrazinelevels are maintained as per water qualityrecommendations.

Whenever feedwater pH becomes lower than 7, tripthe boiler and safeguard the boiler from low hydrogendamage.



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Check the temperatures of FD fan Plummer blocksare normal. If abnormal, record in logbook forchange during shut down.

Keep the FD fan Plummer blocks clear from dust

accumulations. Every shift the dust shall be clearedoff the Plummer block.

FD SYSTEMFD SYSTEM


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Check the fan inlet wire screen is freefrom blockage. The wire screen getsblocked due to rope, waste paper, etc.

Check motor body temperature is normal.

If overheating is observed notify electricalpersonnel.

FD SYSTEMFD SYSTEM


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Check the power cylinder is free from dustaccumulations.

FD FAN POWER CYLINDERFD FAN POWER CYLINDER


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Check the air heater gas outlet

temperature and air outlet temperaturesare normal. Use these values to identifyairheater tube failures.

Check O2 values before & after APH ongas side. If there is increase in O2 after

APH, the APH needs inspection.

AIRHEATERAIRHEATER


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Check the Airbox is free from bed

material. The compartment drain valveshall be operated with FD fan on.

Check bed temperature thermowell cooling

air is 0.1 kg/cm2.Check compartment air operated powercylinders are in normal working condition.

AIRBOXAIRBOX


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Clean up the fuel feeders.

Check the feeder motor body temperature

is normal.Check the oil level is geared motor isnormal. If any leakage is observed the sealsshall be changed.

Check the feeder bearing temperature isnormal.

Measure and record the feeder motorcurrent. Compare the present reading withearlier reading.

FUEL FEEDING SYSTEMFUEL FEEDING SYSTEM


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Check the chain & sprockets of the feederare free from dust. Chain shall be

lubricated with light oil.Check the VFDs of fuel feeders are notoverheated.

Check the VFD is free from dust. Dustshall be removed using hand blower.

Check the fuel is of right size.



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Check bunker top inspection doors are in

closed condition. Otherwise foreign materialcould go inside.

Check the feeder rpms are normal. If

there is large variation there should areason such increase in moisture content /ash % / Lower GCV. Otherwise check foraccumulations in feeder.



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Check the damper openings are not disturbed.

Ensure the secondary air pressures are set as perload requirement.

Check the manometers / draft gauges indicating

the pressure settings are in proper workingcondition.

SECONDARY AIR SYSTEMSECONDARY AIR SYSTEM


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Check the damper openings are not disturbed.Ensure the air pressure is normal.

Check the PA fan header pressure is normal.

Check the PA fan current is normal. PA fan currentincreases when the mixing nozzle is worn out.

PRIMARY AIR SYSTEM


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Check the thermocouples are working. If notworking, replace the thermocouples. Order for

spare thermocouples.Check Airbox pressure and air flow are normal.Check the bed height is normal and is at least300 mmWC to avoid static burning and thus clinkerformation.Check compensating cables of thermocouples arefree from possible damage, from hot bed material.

FURNACEFURNACE


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Check the bed material is free from stones,clinker. Bed material as required for one chargeshall be kept on stock.

Always maintain a constant bed height. Beforedraining bed material charge the same quantity inthe furnace. Drain the bed by opening the drain

gate partly but never fully. This is to ensure thatthe bigger size particles are removed effectively.

Never keep any compartment under slumped

condition for long. It could lead to caustic gougingin bed coil.

FURNACEFURNACE


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Check for abnormal bed temperatures in anycompartment. It implies clinker has formed in the

bed. It is advisable to drain the bed and replace toremove clinker pieces. If not, the boiler has to beshut to clean the bed. Running with clinkered bedleads to localized bed coil erosion.

Cross check the O2 % with orsat apparatus oncein a week.

FURNACEFURNACE


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Check the glands of valves in the Deaerator &feed water storage tank are free from leakages.

In the level station, check the signal connectionsof I/P transmitter & positioner are proper.

In the pressure control station, check the signal

connections of I/P transmitter & positioner areproper.

Look for damage in insulation. Repair thedamaged insulation.

DEAERATORDEAERATOR


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Check the local level gauge levels are tallying withthe panel indication.

Observe the steam plume & adjust if required.

Use initial heating line to boost up the deaeratoroutlet water temperature in case it is too low.

DEAERATORDEAERATOR


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Check the current taken by the feed pump isnormal.

Check the lubrication to bearings is normal.

Change over to stand by pump every month to

ensure the next pump is operational. Do this onfixed dates. Check cooling water flow is adequateand temperature is normal.

Operate the drain of the suction strainer of thefeed pump.

FEED WATER SYSTEMFEED WATER SYSTEM


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Check the continuous blow down is open.

Operate the drain valves of bed coil headerswhenever the beds are slumped. This is to removethe sludge / suspended matter that may settledown in the headers over a period of operation.

The blow down shall be given when the boiler isstill under pressure.

Check the remote drum level indication is

matching with local direct water level gauges.

BOILER SYSTEMBOILER SYSTEM


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Check the water level gauge is working

satisfactorily. Remote level indications can beverified only with direct water level gauge.

If water is running down the gauge glass check

for suspended impurities in boiler water. Useantifoaming chemicals to control.

BOILER SYSTEMBOILER SYSTEM


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Make sure safety valve exhaust pipe is notblocked by foreign material such as dead birds.

SAFETY VALVESAFETY VALVE


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Check the spray control valve opening is notabnormal.

SUPERHEATER SYSTEMSUPERHEATER SYSTEM


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Check the ESP field current is normal.

Check all heaters are functioning.

DUST COLLECTION SYSTEMDUST COLLECTION SYSTEM


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FUEL HANDLING SYSTEMFUEL HANDLING SYSTEM


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Check crusher hammer condition & replace ontime schedule. Worn out hammers produce oversizeparticles and increase recycling load to screen.

Check oversize chute is not overflowing andmixing up with right size fuel.

Use coarser coal during monsoon times.

Check conveyor belt condition periodically to avoid

major shut down.


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Check and remove the screen blinding by ropes,stones etc.

Replace the screen if found damaged.


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Check the ash is being discharged from all ash

points.

Check the LOI in the ash remains normal.

Check the dense phase vessels are evacuatingash from hoppers above. Abnormal ash

accumulations can damage the boiler.

ASH HANDLING SYSTEMASH HANDLING SYSTEM


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Flush condensing pots occasionally to clear thedirt trapped. Isolate the transmitters whileflushing.

INSTRUMENTS & CONTROLINSTRUMENTS & CONTROL


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If any control valve is hunting set right the PIDvalues.Make sure the combustion control does not raise

the feeder rpm abnormally.

INSTRUMENTS & CONTROLINSTRUMENTS & CONTROL

boiler inspection -daily

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