What is condensate The steam after condensing in the condenser known as condensate, is extracted out of the condenser hot well by condensate pump and taken to the deaerator through ejectors, gland steam cooler and series of LP heaters.
Condensate system• Condensate Extraction Pump : To pump out the condensate to D/A throughejectors, GSC and LPH• Gland Steam Condenser : To increase the temperature of condensate.• Condensate polishing unit : To remove cat-ion and an-ion from thecondensate.
CEP • Converts last stage steam of LPT to water CEPCONDENSER DEAREATO GSC CPU R LEVEL CONTROL CONDENSER Minimum recirculation to condenser
Condensate Pumps The function of these pumps is to pumps out the condensate to the deaerator thru ejectors, gland steam cooler, and L.P. heaters. These pumps have FIVE stages and since the suction is at a negative pressure, special arrangements have been made for providing sealing.
Stages: The pressure build up in 5 stages as suction is at negative pressure.Recirculation: It is done when the de aerator level controller trips in order to prevent cavitations.
CEP LINE UP Ensure PTW cancelled Ensure box up Suction strainer drain/vent close Open canister vent Open re-circulation manual v/v c/v inst. Air v/v Seal water charge Bearing cooling water charge Bearing oil level normal Relief v/v manual v/v open Suction v/v open Relies EPB
Supply normal Hotwell level N low ( > - 250mm) SWGR available SWGR not disturbed Thrust brg temp not high Motor brg. Temp not high Motor wdg temp not high R/c v/v open > 40 % Discharge vent open Discharge v/v close or stand by selected
CEP ISOLATION EPB pressed Breaker rack out Is R/c v/v passing Close suction v/v By pass relief v/v close Close re-circulation v/v Close canister vent v/v Discharge vent manual v/v close Close sealing water v/v Close cooling water v/v Crack open strainer vent. Is there any air sucking?
Boiler Feed Pump To give the required pressure to the feed water before entering into boiler Horizontal barrel type multi stage pump.
BOILER FEED PUMPNDE BEARING DE BEARING SLEEVE KEY FOUNDATION BOLT SOLE PLATE (BASE PLATE) 18
General Arrangement of BFP To HPH. Recirculation to FST Feed Water From D/A Suction Strainer Main Motor PumpBoosterPump S S for Hydraulic Main Pump Coupling
Components of BFP Booster Pump To Ensure a Net Positive Suction Head (NPSH) for Main Feed Pump Saves a Costly Main Pump due to any damage from Cavitation. Typically a single-stage, centrifugal pump Recirculation :To maintain the Continuous flow of feed water when the valve to Economizer is Closed
Components of BFPSuction StrainersTo Protect Booster pump and main pump against Catastrophic failure due to entry of coarse particlesHydraulic CouplingUsed to Transmit power from motor to pump as per the Load requirement
NPSHNPSH is an acronym for Net Positive Suction Head . Itshows the difference, in any cross section of a generichydraulic circuit, between the pressure and the liquid vaporpressure in that section.NPSH is an important parameter, to be taken into accountwhen designing a circuit : whenever the liquid pressure dropsbelow the vapor pressure, liquid boiling occurs, and the finaleffect will be cavitations : vapor bubbles may reduce or stopliquid flow.In pump operation, two aspects of this parameter are calledrespectively NPSH (a) Net Positive Suction Head (available)and NPSH (r) Net Positive Suction Head (required), whereNPSH(a) is computed at pump inlet port, and NPSH(r) is thelimit NPSH the pump can withstand without cavitating.
Booster Pump Major damage in BF pump is from cavitation or vapour bounding. Provides positive pressure at the pump suction.
MECHANICAL SEAL• The use of mechanical seal reduces the loses of feed water in the stuffing box to a minimum.• Working ability of the feed pump increases.• Cooling of stuffing box space should be perfect by the use of mechanical seal.• Cooling is carried out by the circulation of water between the stuffing box space and the cooler. Even after stopping the pump stuffing box cooling should be continued as its cooling circuit is different from the seal cooler.• Coolers are designed to keep the stuffing box space temperature below 800C.
MECHANICAL SEALIt consists of two highly polished surfaces, one surface connected to the Shaft and the other to the stationary part of the Pump.• Both the surfaces are of dissimilar materials held in continuous contact by a spring.• These wearing surfaces are perpendicular to the axis of Shaft.• A thin film of working fluid between these faces provides cooling & lubrication.
Line Bearings• They give radial positioning to the rotor.• They are of two types :• Antifriction Bearings• Sleeve Bearings
Thrust BearingsThey locate the rotor axially & take residual axial thrust.• They are fitted in the NDE Bearing Housing.• They have 8 white metal lined tilting pads held in a split Carrier Ring positioned on each side of the Thrust Collar.
BEARING HOUSINGS• They house Journal Bearing at the DE side and both Journal & Thrust Bearings at the NDE side.• These are in the form of cylindrical castings split on the horizontal Shaft axis, located one each at DE & NDE sides of the Pump.
PUMP CASINGIt houses the hydraulic components of Pumps.• It prevents the leakage and guides the liquid in a proper direction.• It is closed by Suction Guide at it’s suction side and Discharge Cover at it’s discharge side.
SUCTION GUIDE• It guides the fluid from suction pipe to the eye of the Impeller.• It closes the drive end of Pump Casing and forms the suction annulus.
DISCHARGE COVERIt closes the NDE of Pump Casing and forms the balance chamber.• It is closed by NDE Water Jacket and Mechanical Seal Housing.• A Spring Disc is located between the last stage Diffuser and the Discharge Cover Balance Drum Bush.
IMPELLERIt rotates the mass of fluid with the peripheral speed of its vane tips, thereby determining the head developed or the Pump working pressure.
DIFFUSE R• It converts Kinetic energy of the fluid into Pressure Energy.
ROTATING ASSEMBLY• It consists of Shaft, Impellers, Balance Drum, Thrust Collar, rotating parts of Mechanical Seals and the Pump Half Coupling.• It is dynamically balanced.
Balancing Device• A small portion of the feed water in the order of about 10% which is not calculated to the guaranteed delivery capacity is taken off from the space behind the last impeller for the operation of the automatic balancing device to balance the hydraulic axial thrust of the pump rotor.• The purpose of the balancing device is to take up thrust pressure in a similar way as the thrust bearing. BALANCE DRUM
BALANCE DRUM The Balancing Chamber is connected either to the Pump suction or to the Deaerator, thus the back pressure in Balancing Chamber is slightly higher than the suction pressure. 95% of axial thrust is balanced by the Balancing Drum. Residual axial thrust is taken by Thrust Bearing. Provision of Thrust Bearing is recommended for varying condition of Head and Flow which affect the axial thrust.
MDBFP LINE UP OIL SIDE1. HC oil level normal2. Cooler line up3. Start AOP4. Lube oil WO pr. Ok5. Bearing oil flow normal6. No oil leakage
Suction v/v open fully R/c v/v manual v/v open R/c v/v c/v inst. Air v/v open* Motor wdg cooling water supply/ return line v/v open Cooling water header pressure ok Main p/p and booster pump mechanical seal water / cooling water charge Venting done* EPB released Discharge v/v close and IBV close Header drain /recirculation/casing drain close *
TDBFP LINE UP OIL SIDE FEED WATER SIDE GLAND SEAL STEAM/ VACUUM SIDE EXTRACTION STEAM SIDE BARRING SIDE
TDBFP LINE UP PTW CANCELLED BOXED UP OIL SIDE1. LOT level normal2. Cooler line up from oil /water side3. AOP/EOP/JOP suction/discharge v/v open4. Governing oil manual v/v open5. All lops supply normal6. Start EOP and check oil lkg.7. Start JOP and check oil lkg8. Pump/turbine freeness checking, observe RPM9. Stop barring engage/disengage main p/p and do FW charging10. Vapour extraction fan i/s
FW charging1. Open BP/BFP/suction strainer vent2. Charge mechanical seal water BP/BFP3. Charge jacket cooling wtr and one set of cooler4. Crack open suction v/v *5. Taking on barring along with FW charging?6. Close all drain /vents
Gland seal steam /vacuum side1. Open aux stm. drain at 8.5 M then crack charge2. Open seal steam /aux c/v drain and crack charge 8.5 m iso. v/v3. Charge seal stm / leak off stm side4. Open turbine drains to flash tank to take vacuum5. Crack open exhst. block v/v and close ,try again Extraction stem side1. Open drain/vent before ESV2. Open manual v/v3. Open mot. v/v