TURBINE DRIVEN BOILER FEED PUMP EREC. &COMMNG -ABC OF THERMAL POWER PLANT

As  stated in earlier posts there are three Boiler Feed Pumps (3x 50%) in a thermal power station of 500MW and above. 2x50% turbine driven BFP ( normally working when unit is running above certain load ) and other is 1x50 % MDBFP  which usually runs during start up .

We have already explained in last few blogs about erection and commissioning of MDBFP . For TDBFP pumps are same whether it is booster pump or main pump. Instead of MOTOR driven we have variable speed turbine with disconnecting coupling both sides . In this blog we will discuss only the turbine as pumps are similar.

 Technical data of Turbine

a.  Maximum output                                         7575  KW

b.  Design rating 

        (Economical rating)                                  5732 KW

c.  Speed                                                            5275 RPM

d.  Speed range                                                  1494-5750 RPM

e.  Initial Steam Pressure                                   6.33 ata.

f. Initial steam Temperature                              289.6 0 C.

g.  Exhaust pressure                                           0.1064 ata.

Oil System

a.  Lube oil pump                                              2 Nos

b.  Emergency Oil pump                                   1 No.

c.  Jacking Oil Pump                                         1 No.

d. Oil vapour extractor fans                              2 Nos

PROCESS  : ERECTION CHECK

Foundation checking of elevation ,plan that is different pocket holes and other measurable items as per given approved drawing . This the protocol for taking foundation from civil vendor for erection  purpose .(elevation within+5mm/-10mm). 

Check that depth and verticality of each pocket is OK. Checking to be done by water level /dumpy level/ total station.

Distance from fixed reference axis e.g. A-row, B-row Columns.  (1mm / metre,  5mm Max.)- Establishing centre line as given in the drawing by putting distances from fixed point . This can be done by measuring tapes or by total stations .

Marking of equivalent axes on foundation. Plumb Bob / total station.

Fitting of half couplings to all equipment after ensuring corresponding fits.  For taper coupling, ensure around 80% contact between shaft & coupling.

Blue matching the top surface of foundation frame with corresponding bottom surfaces of equipment with around 80% contact.

Positioning and alignment of all equipment on the foundation. Measure distance between coupling half faces of following equipments by Vernier / Micrometer / Tape

            Booster Pump and Gearbox

            Gearbox and Drive turbine

            Drive turbine and BFP.

Grouting of Foundation Bolts. Check that nut has full contact with foundation frame after tightening.

Leveling and alignment of equipment  by jack bolts (within 0.1 mm / M). Dumpy / Precision Spirit level) and different thickness packer plates.

Foundation frame grouting. Now a days grouting is done with ready mix concrete of 25kg bags main supplier is ACC, PAGEL ,FOXROC etc. This is a specialised job it is advisable to do concreting in presence of suppliers representative to avoid any complicacy afterwards. Please insist on test certificate and cube testing on one day and three day sample. This may delay the process however by passing any of the test may complicate the situation afterwards. Major checks of equipment are already told during my earlier blog. Please go through it.

Alignment (lateral and angular) between booster pump & gearbox, gearbox & Drive turbine shaft, Drive turbine shaft & BFP, Measure distances between coupling flanges. This is done without any pipe connection ( water line ,oil line and steam line ). This is pre final reading and after doing final connection final reading to be taken. However during course of erection this reading is checked to find the effect of connection. Dial Gauge/Micrometer.

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to know about  PTC please read my other blog "common man"

Continued  to part –ii ( TDBFP)