BCW Pump

BCW Pump
STARTING THE BCW PUMP : -
F.1 PRE START CHECKS BEFORE INITIAL STARTING OF THE PUMP
1 Boiler Drum is filled & drum level is maintained on positive side (+200 mm) for starting first
pump.
2 SGECW System & BCW Booster Pump is in service.
3 Emergency over head tank level OK.
4 Ensure that pump & pump cooler is completely vented.
5 Start permissive is available.
6 LP cooling water valves are open and the cooling water flow is > 75 LPM.
7 All other valves must be closed.
8 LP & HP purge lines are charged and purge line valve to motor is in closed condition.
9 Check for any water leakage from pump instruments, cooler vent, pump & motor assembly.
10 With water filled, the insulation resistance measured at the terminal links, using a 1000V
megger must exceed 200 mega ohms.
START PERMISSIVE
1 No Switchgear disturbance.
2 Switchgear Available
3 Drum N2 Vent Valves Closed.
4 Motor Cavity Temp Not high (57° C).
5 Suction Manifold / Casing DT not high (< 38° C).
6 BCW P/P Cooling Water Flow Adequate (> 75 LPM).
7 BCW P/P Not Tripped.
8 Both Discharge v/v Stem open.
9 When a boiler is started from cold, a minimum of two BCW pumps must be operated. It is
normal practice to start all the three pumps before boiler light up
Starting of pumps
1 Start the first pump
2 Motor current will drop from full starting current after few seconds to normal & there is no
hunting in current.
3 Ensuring Drum level is normal start second pump (after starting of pump it tends to dip).
4 Differential pressure should rise immediately to approx. 3.1 kg/sec².
5 Check with local operator about any abnormal sound from pump.
6 Ensure for the standby pump that DT between pump casing & boiler water is within 56° C.
7 Caution –If motor fails to start after 5 seconds, press stop button & do not attempt to
start the pump for 20 minutes.
FOR STANDBY BCW PUMP:
1 Close the service valve in pump jumper line & open the pump discharge by-pass valve. This
ensures that as the boiler heats up, a flow passes from the discharge legs to the pump case &
impeller.
2 Check the motor cavity temperature is not exceeding 49 ° C.
3 In such a case take the pump in service & close pump discharge by-pass valve & open the
pump jumper line service valve.
ISOLATION PROCEDURE
There is no provision to isolate the pump in boiler lighted up condition as no isolation
v/v is provided in suction line, only two manual v/v are provided in the two discharge
lines.
PROTECTIONS
1 PUMP Motor Cavity Temperature Very High with a time delay of 5 sec (> 60 ° C).
2 Discharge Valve Stem-1 not open
3 Discharge Valve Stem-2 not open