TURBINE DRIVEN BOILER FEED PUMP COMMNG CONCLUDING PART ABC OF THERMAL POWER PLANT

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 .