Steam rolling and actual overspeeding of Turbine (solo run of
turbine) of Boiler Feed Pump
Check that Gear box and
main pump are disconnected from the turbine.
Check turbo -visory system is working properly (i.e
calibration is over).
Check proper clearance at
the holding down bolts of turbine casing and front bearing pedestal.
Check tightness of
flanges in the turbine casing and exhaust line.
Check that all the
temporary supports are removed from turbine casing, steam lines, oil lines etc.(i.e
turbine is free from any restraints ).
Ensure that the TD BFP
foundation is separated from the main turbine foundation all around and the
support spring assembly of TD BFP is properly placed.
Start oil system. Keep
the turbine on hydraulic barring. Record the measurements of oil system and
turbovisory.
Install dial gauges for
checking even expansion of the casing and pedestal as a precautionary measure (
back up of turbovisory specially during over speed test).
Warm up gland sealing
steam supply header ensure measurement of sealing steam supply temperature.
Keep open casing drain
and balance piston loop drain valves.
Observe vacuum created in
turbine casing and exhaust line. Check for tightness of exhaust line and casing
joints.
Keep the gland steam
controller on auto and observe that it maintains properly.
Gradually open the
exhaust butterfly valve in steps, keeping a watch on the vacuum in the condenser.
Check the protections of
the turbine as given in the control scheme.
Keep open all drain
valves ( steam) associated with TDBFP under commissioning.
Ensure governing oil
system charged and ESV in close Condition.
Warm up the steam inlet
line to turbine (Steam supply can be taken from any one of the available
sources)
Ensure steam inlet
pressure, temperature and flow measurements are healthy.
Reset the turbine and
observe the trip oil pressure is available.
Ensure steam purity as
recommended in O & M manual.
Ensure isolating valve in
the steam supply source to turbine is opened full and all the drain lines are
hot( important).
Ensure steam parameters
are achieved as per O&M manual
Open emergency stop
valve.
Raise the speed of the
turbine gradually to 1500 RPM, keeping a close watch on bearing metal
temperature, shaft vibrations, casing expansions and for any rubbing noise.
Check whether JOP is
switching off and turning gear valve closes at speed of 500 RPM.
Soak the turbine at 1500
rpm for about 30 minutes observe the parameters are stablised.
Raise the speed of the
turbine gradually to rated speed as per start up curve, given in O & M
manual.
Monitor the behaviour of
control valve during warming up speed and at rated speed for any hunting.
At rated speed soak the
machine for 15 minutes, observe for all parameters. Adjust lube oil flow to
bearings if required.
Carry out oil injection
test of overspeed governor for few times to check repeatability of the action.
Keep exhaust hood spray
system on auto. Ensure its operation.
Carryout actual
overspeeding test of the turbine if the parameters such as vibration ,temperatures
,expansion within limits
If actual overspeed trip
does not occur at required value, hand trip the turbine and adjustment to be
done at emergency governor.
Keep the hot turbine on
hydraulic barring, ensuring gradual cooling down.
Commissioning of Turbine Driven Boiler Feed Pump.
Ensure alignment readings
are logged and cleared for coupling.
Couple turbine with BFP
and Gearbox. Couple gearbox with booster pump.
Crack open feed water
suction isolating valve and vent out air in all the vents.
Flush and shut the
booster pump casing drain and BFP drain and interconnecting pipe drain.
Check all the instrument
tapping point isolating valves are open and that all drain and equalizing
valves are shut.
Gradually open suction
isolating valve keeping watch on the trend of differential temperature of top
and bottom of the main pump casing.
Check mechanical seal
water control isolating valves are open for Booster pump and BFP.
Check magnetic separator
isolating valves for BFP seal water are open.
Ensure cooling water flow
through all coolers.
Ensure isolating valves
in re-circulation line and leak off line are open.
Ensure all c&I points
are healthy and available at DCS/local.
Ensure proper clearance
at the holding down bolts of the booster pump and main pump.
Check the booster pump
and main pump.
Ensure oil system in
service. Start jacking oil pump.
Engage the main pump with
turbine.
Check the freeness of
Turbine rotor along with booster pump and main pump by hand barring.
Disengage the main pump
and keep the turbine on hydraulic barring and prepare the turbine for steam
rolling.
When the turbine is ready
for steam rolling, stop the turbine and engage the main pump with turbine.
Keep the turbine along
with main pump and booster pump on hydraulic barring.
Raise the speed of the
TDBFP to rated speed as per start up curve.
Keep the pump on
recirculation flow of approximately 250 T/hr for 8 hours to observe and record
performance.
Check the speed control
and pressure variations during operation of BFP for drum level control.
During trial operation
feed water suction strainers of Booster pump and BFP should be closely
monitored.
Stop TDBFP after trial
run, put turbine on hydraulic barring .
