CONDENSATE EXTRACTION PUMP SPECIFICATIONS
Type of first impeller : Double Suction
Number of stages : 5
Design flow rate : 8,10,00 Kg/hr
Inlet – Temperature : 43.1OC
Inlet - Specific Gravity : 0.991
NPSH required : 4.1 meter
Discharge pressure : 30.4 ata
Total Dynamic Head : 307 meters
Shut off Head : 398 meters
Pump Speed : 1480 rpm.
Power Consumption at Design Condition
Power input at the motor : 899.2 KW
Losses in the motor : 41.4 KW
Power input to the pump : 857.8 KW
Efficiency of the pump alone : 79.0%
Overall efficiency of the pump motor : 75.37%
Guaranteed power consumption with a flow rate of 605,000 kgs/hr.
: 776 KW.
Sealing Water requirement
Flow : 10 litre/min
Pressure : 2-4 ata
Temperature : 30-50OC
Minimum flow for continuous stable operation : 350 T/hr
Suction stainer size : 350 microns
Radial Bearings lubrication with Water : 4 Nos.
Motor Specification
Output : 1120 KW
Voltage : 6.6 KV
Number of poles : 4
Speed : 1480 rpm
Cooling water Requirement for one motor
Motor upper Bearing-Thrust Bearing : Oil lubricated
Flow : 30 litres/min
Pressure : 2.0 to 7.0 Kg/cm2
Max. Inlet temp. : 40OC
Motor inner bearing lubricated with : Grease
Coupling : Rigid Type
Rating : 1500 HP
Size : 360 mm
Condenser
Type : Twinnest, Double pass,
Single shell
Area of cooling surface : 3253 M2
Number of xooling tubes : 24710
Lenth of each tube : 14730 mm
Size of tube-(OD x thickness in mm) : 28.575 x 0.7112 Tube material - Stainless Steel tubes : SS.304
Weight of empty condenser : 640 MT
Weight of tubes : 180 MT
C.W. flow : 55017 m3/hr
C.W. velocity : 2.13 M/s
C.W. design temperature : 28OC
C.W. Max. temperature : 35OC
Back pressure at MCR : 60.45 mm of
Temperature rise max. : 10.56OC
Terminal temperature Difference : 3.17OC
Head loss on C.W. side : 6.3 MWC
Fouling factor : 0.9
Condenser tube cleaning system
Name of the supplier : TAPROGGE
No. of Cleaning systems : 2
No. of Balls : 800 Nos.
Strainer Section
Quantity per TCS : 2 Nos.
Slope of Screen : 30OC
Width of Gap : 10 mm
Cooling water : 7.639 kg/s
Actuation : Motor operated
Ball recirculating pump
No. : 1 per unit
Type : KWPK-80-250
Normal capacity : 45 m3/hr
Normal discharge pressure : 1.8 bar
Pump motor : Siemens
Operating voltage : 415V/50 Hz
Rated output : 5.5 KW
Full load speed : 24
CONDENSATE EXTRACTION PUMP - DESCRIPTION
Each condensate extraction pump which is driven by a 1120 KW induction motor, delivers 810,000 kg/hr of condensate water against 307m. Of total dynamic head at the rated condition.
CONSTRUCTION OF C.E. PUMPS
The pumps are of the direct driven by a constant speed motor through a rigid coupling, vertical barrel, double suction, multi stage, diffuser type.
The pump consists of internal assembly, discharge assembly and suction barrel. The internal assembly comprises of 5 stage casing, a guide vane, five impellers, 2 column pipes, a suction bell and shaft and is submerged in water in the suction barrel.
The discharge assembly comprises a discharge head with a stuffing box to seal the pump shaft and is installed on the suction barrel. The suction barrel is installed on the pump floor.
Water is admitted into the casing from the suction barrel through the suction bell and first stage casing and discharged through the column pipes by the energy imparted by the impellers.
CONDENSATE SYSTEM
Internal bearings (Leaded bronze bearings) installed in a column pipe and the top casing are provided for supporting the pump shaft against the radial load. Upper and lower bearings (leaded bronze) are installed in the stuffing box and suction bell.
The weight of the pump rotor and the hydraulic thrust acting on the rotor in the axial directions are supported by the thrust bearing in the motor.
The impellers are driven by a 1120 KW vertical shaft induction motor mounted on the discharge head. The coupling spacer is furnished between the pump and motor in order to remove the gland and seal ring seal without removing the motor.
Adjustment nut is provided at the top of the drive shaft to facilitate adjustment of the axial location of the rotating part.
Gland packings are used for shaft sealing.
Start up Checks
Check that there is no foreign material in pump.
Check that the condenser is cleaned up. If the condenser is dirty, suction strainer of pump will be clogged frequently. Suction strainer shall be kept installed during initial operation and remove it after system gets cleaned.
Open suction valve fully and fill pump with water. In this process air vent valves shall be fully opened to purge air completely.
Ensure that the following valves are opened.
1. Suction valve
2. Sealing water inlet valve
3. Iso. Valves of respective coolers 4. Balance valve.
5. Pump’s Recirculation valve.
Keep the pump’s disch valve closed.
Check the water level in the condenser is adequate.
Check that lub. oil is filled up to the mark.
Turn on circuit breakers of respective equipment’s and auxiliary devices.
Once the pump is started and reaches full speed, trip the pump.
Check that there is no abnormal noise etc.
Restart the pump
Check the condition of gland leakage. It should be just in continuous drips.
CHECKS DURING OPERATION MECHANICAL
1. Do not operate the pump with the discharge valve closed for more than a few minutes.
2. Sufficient care shall be taken for abnormal noises.
3. Observe bearing temperatures, vibrations, discharge pressure etc.
4. Ascertain that all indicators show proper value under pump running condition.
5. Gland sealing water pressure 1 to 3 kg/cm2
6. Pump bearing temperature Max. 80OC ELECTRICAL
1. Motor input power shall be checked.
2. Over load conditions shall be checked which will badly effect motor service life.
3. Power source voltage fluctuation shall be checked.
4. Over current shall be carefully checked.
5. Motor winding temperature to be within limits.
SHUT DOWN
When the pump is shut down for standby duty, care shall be taken on the following : 1. Switch off the motor
2. Pump discharge valve will be completely closed and selected to auto.
3. Space heaters should remain switched on.
LONG PERIOD SHUT DOWN
1. When the pump is not used for more than one month, operate the pump for approximately 30 minutes, to keep the equipment in good condition.
2. Cooling water system should remain isolated.
3. Space heaters should be kept on.
ISOLATION
Isolate the motor electrically.
Isolate the cooling water system and drain it.
Pump Discharge and suction valves, balance valve, will be closed as the pump will be drained.
Pump’s sealing water system will be isolated.
CONDENSATE SYSTEM DESCRIPTION OF SYSTEM
The purpose of this system is to store an adequate quantity of demineralized water to meet the make-up requirements for normal cycle fluctuations and for abnormal operating conditions when supply of demineralized water is interrupted. In addition, this system will transfer condensate to and from storage tanks as needed to satisfy main cycle requirements.
The main cycle flow and thermodynamic requirement is maintained by transporting the condensate collected in the condenser hotwell through various stages of feedwater heating and other equipment to the deaerating feedwater heater.
The condensate extraction pumps normally deliver the condensate through the three low pressure feedwater heaters, the deaerating feedwater heater to the deaerating storage tank, which is the beginning of the feedwater system. The low pressure feedwater heaters receive extraction steam from the turbine. The condensate absorbs heat from the extraction steam as it passes through the feedwater heater. The deaerating feedwater heater further preheats the condensate prior to its entry into the deaerating storage tank. The condensate in the deaerating feedwater heater is warmed by extraction steam during normal operation and auxiliary steam & cold reheat steam are utilised as the heat source during start-up & turbine shut down condition.
The normal make up to the condenser is supplied from the demineralizing plant through the make up pumps. In case of fluctuations in the cycle, condensate will be transferred to and from the condensate storage tank as required. Normally, on low
level in the condenser hotwell, condensate will flow from condensate storage tank to hotwell by static head in the tank and differential pressure due to condenser vacuum, however, should this flow be inadequate, the condensate, transfer pump will supplement the flow. This make up is sprayed into the steam space above the tube bundles.
The condenser hotwell is condensate collection vessel, integral with the condenser shell, and located in a pit below the ground floor.
Condensate collected in the hotwell is pumped by 3 x 50 % Condensate Extraction Pumps to the feed storage tank through feedwater heaters placed in series. Two lines from hotwell, make a common header where from three lines are connected at the suction of three Condensate Extraction pumps. A strainer is placed at the suction of each condensate Extraction pump to collect debris during commissioning.
The suction piping to the pumps is vented back to the condenser, to insure that the non-operating pump(s) stays completely flooded. These vent lines include manual valves on the vent for each pump.
A minimum flow (350 T/Hr) recirculation line for each pump is provided, returning to the condenser via a flow control valve and a locked open shut-off valve.
The shaft seals of these pumps are the water-injected type fed from a header to prevent the suction of air, particularly the pump that is not operating while the condenser is under vacuum.
One discharge line emerges out from each condensate extraction pump with one check valve and one motor operated stop valve placed in series. These lines from a common discharge line and enters the turbine gland steam condenser.
SYSTEM CONTROL
Three 50 % Condensate Extraction Pumps shall be controlled from the Central Control Room (UCB). The Condensate Extraction Pumps are protected by safety interlocks to prevent eventualities like dry running, low NPSH and minimum flow conditions. The pumps are provided with Auto starting feature. A three position selector switch inscribed with ‘LEAD-NORMAL-LAG’ has been provided to select the pump for Auto Starting. The first pump to be started on ‘Auto’ shall be selected in ‘Lead’ position and the second stand by pump shall be selected in ‘LAG’ position. Any pump can be selected for Auto start either in ‘Lead’ or ‘Lag’ position.
The pump on standby duty is streamlined to automatically start in the event of decreasing discharge header pressure below 30 ata (approx.) through’ 0-15 secs.
delay or if the CEP disch. Header flow exceeds one pump capacity (810 T/Hr. Approx.) through’ 0.5-5 secs delay or a trip of the running pump. Pressure switches provides actuating signal for stand by pump to start.
Each condensate extraction pump’s suction strainer is provided with differential pressure switch. These switches actuate control Room alarm in the event of high differential pressure (0.1 kg/cm2 approx.).
The condensate extraction pumps are also provided with level switches that monitor condenser hotwell level. The level switch protects the Condensate pumps from operating under very low (-1290 mm) suction head conditions. One level switch provides a pre-alarm for a low level (-1140 mm) condition. Low suction conditions are usually encountered during start-up or transient plant operations.
The condenser hotwell is normally maintained by the operation of two level control valves. Normal level is maintained by level control valve LCV 0508 sensed by flow transmitter LT 0508. In the event this level control valve is unable to maintain normal level, the emergency make up control valve LCV 0509 comes into action, sensing low level in the hotwell by flow transmitter LT 0509.
Normally the emergency make up will flow from condensate storage tank to hotwell by gravity. But even with above flow the hotwell level becomes low (sensed by level switch) then the condensate transfer pump shall start and its discharge valve shall open automatically. When the hotwell level is restored to normal level the above valve shall close automatically. Full closing of this valve would cause auto stopping or associated condensate transfer pump.
Condensate spill control valve is provided in the line that connects the discharge header (after gland steam condenser) to condensate storage tank. This level control valve is automatically positioned by the hotwell level controller when a high hotwell level condition develops. Condensate is then transferred to the condensate storage tank until the hotwell level returns to normal. The condensate spill control valve is also provided with a motor operated. Bypass valve which can be operated manually from UCB in the event of controller malfunction.
Each condensate extraction pump is equipped with individual recirculation control valve which ensures minimum flow through condensate pump when individual pump discharge flow falls below 350 T/Hr. sensed by flow transmitters. Beside above, to ensure minimum flow through the gland steam condenser, a minimum flow recirculation line and control valve is connected from the discharge header before Deaerator level control block valve back to condenser.
During normal operation, condensate passes through the LP heaters 1,2 & 3.
However, in the event of very high level in individual heater the condensate is automatically bypassed by interlock action. For this reason motor operated. bypass valves are placed across LP Heater respectively. In the event of very high water level in each LP Heater, sensed by level switches, the individual bypass valve opens and inlet-outlet motor operated isolation valves in each heater gets closed. Restoration of the heater level to normal will not automatically restore the heater to service. The return to normal operation must be initiated by operator action.
A three element (Deaerator level, Deaerator input flow & feed flow), control loop is employed to maintain Deaerator level. Deaerator level is sensed by level transmitter A
& B. This input is fed to a controller where signal from feed flow as well as Deaerator input flow i.e. the sum total of condensate and Heater drain flow is fed. Either of the two 100% flow control valve, position automatically to maintain the Deaerator level, receiving input from the controller.
In the event of high level in Deaerator, sensed but level switch, the level is restored by opening automatically the Deaerator high level drain valve. If the rise in level still persists and reaches very high level (+440 mm), sensed by level switches, then Deaerator level control block valves (on main condensate line) shall close automatically.
On restoration of normal level above block valves have to be opened manually from remote. The drain valve shall close automatically when the Deaerator level falls below the high level.
When conductivity at the outlet of each vessel of the condensate polishing unit becomes more than 0.1/us/cm, the unit regeneration shall be started by manual intervention.
BOILER FEED PUMP & AUXILIARIES
Booster Pump for BFP : For Motor Driven BFP For Turbine Driven BFP
Manufacturer : Weir Pumps Ltd Weir Pumps Ltd
Type : FATE 64 FATE 64
Direction of rotation Anticlockwise(Viewed on drive end)
: Anticlockwise Anticlockwise
Thrust Bearing
Manufacturer : The Glacier Metal Co. Ltd The Glacier Metal Co. Ltd
Type : Double thrust
Size : M8112/2P/2P
Mechanical Seal for Booseter Pump of BFP
Type : 4" Crane type 8B1. Spring loaded carbon face pressing against a silicaon carbon seat.
Seal Pressure : 9.67 Bar
Temperature : 164.6oC
Shaft speed : 1494 rpm
Seal cooling : Closed loop recirculation via pumping ring through a heat exchanger.
Operating Detail : Motor Driven Turbine Driven Runout Design Runout Design Specific gravity of Feed water
at suction temperature
: 0.901 0.918 0.900 0.918
Suction temperature oC : 164.6 148 164.6 148
Suction pressure bar : 9.67 7.2 8.17 8.17
Discharge pressure bar : 20.27 17.55 20.1 17.76 Differential pressure bar : 10.60 10.35 11.93 12.06
Differential head m : 120 115 135 134
NPSH above impeller eye-M : 30.5 30.5 13.5 13.5
Flow rate m3/hr : 1080.5 1242 1080.3 1242
Efficiency % : 80.5 82 79.5 31
Speed rpm : 1419 1494 1494 1515
Power KW : 395 436 450 514
Boiler Feed Pump Motor Driven Turbine Driven
Manufacturer : Weir Pump Ltd
Type : FK 4 E 36
No. of stages : 4+1 Kicker Stage Direction of rotation viewed
on drive end
: Anticlockwise
SG at suction temperature : 0.901 0.901
Suction temperature oC : 164.6 164.6
Suction pressure bar : 20 19.83
Discharge pressure bar : 205.82 204.32
Differential pr. bar : 182.82 184.49
Differential Head m : 2103 2088
NPSHA above impeller eye m : 50.3 50.2
Flow rate m3/hr : 1080.3 1080.3
Leak-off flow m3/hr : 270 270
Efficiency % : 81.4 81.6
Speed rpm : 5705 5690
Power KW : 6830 6765
Turbine of BFP
Type : K 1401-2
Design output : 5589 KW
Max. output : 9123 KW
Normal Speed : 5330 rpm
Speed range : 2000-6030 rpm
Specified initial steam pressure : 7.182 ata
Exhaust pressure : 0.1 ata
Permissible deviation in initial Steam pressure at No load
: 10.68 ata
Instantaneous deviation (12 Hrs/Annum) : 12.02 ata Max. wheel chamber pressure permissible at : 10.15 ata
full load
Specified initial steam temperature : 300.6OC Deviation without limitation : 322OC Permissible deviation for longer period : 336OC Permissible deviation for 400 Hrs.per annum
for not more than 15 minutes at a time.
: 336OC
Permissible deviation for 80 Hrs/annum for not more than 15 minutes at a time
: 350OC
Specified cooling water temperature : 33OC
Start up time : 38 minutes
No. of stages : 14 Nos.
Type : Reaction
Axial thrust balance : By balance piston at steam
admission side and thrust bearing.
No. of control valves : 5 Nos.
No. of stop valve : 1 No.
Aux. Control valve : 1 No.
Hydraulic speed senser : Primary oil pump
Electric speed sensor : Hall probes
Rotor Support : 2 Nos. Journal Bearing (Front &
Rear)
1 No. thrust bearing. (Front Pedestal)
Over speed trip speed : 6330 rpm
Ist critical speed : 7550 rpm
Direction of rotation of steam flow : Anticlockwise (from direcion of steam flow)
Turbine Auxiliaries
Main oil tank capacity : 6.3m3
Location : 0 meter level
Auxiliary oil pump : 2 Nos.
Discharge flow : 60 m3/hr
Rated head : 9 ata
Drive : Motor
Pump : +ve drive pump
D.C. Oil Pump
Nos. : 1 No.
Discharge flow : 16.25 m3/hr
Rated head : 2.5 ata
Type : Centrifugal pump
Jacking Oil Pumps :
Nos. : 1
Discharge flow : 0.54 m3/hr
Head : 100 ata
Drive : Motor
Pump : +ve drive pump
Voith Variable Speed Geared Coupling for Motor Driven BFP
BFP motor Speed : 1419 rpm
Gear ratio – I : 128/37
Gear ratio – II : 63/51
Primary speed : 4908 rpm
Full load slip : 2.6%
Max. output speed of the variable speed geared turbo coupling.
: 5906 rpm
Regulating range : 4:1 downwards
Oil tank filling : 2500 litres
Filling pump Centrifugal pump)and Lub.
pump (Gear pump)
: Together driven as gear tooth system drive via the pump shaft.
Aux. lub. pump : Three phase motor D 180 M
600/415V 22 KW, 50 Hz 3000 rpm
Lub. oil flow : 388 litres/min.
Boiler Feed Pump Drive Motor
Specifications
Type : Asynchroonous motor with
Squirrel cage rotor
Rating : 9800 KW
Speed : 1493 rpm
Stator voltage : 6.6 KV
Stator current : 987 amps
Frequency : 50 Hz
Limited Axial clearance (Max.) : + 2 mm Lubrication
Bearing Lubrication Type : Oil ring and oil circulation Oil requirement for both : 62 litres
TDBFP
TECHNICAL DETAILS
Turbine driven BFP uses a turbine of 14 stage connected to condenser Turbine is coupled with main pump having an engage/disengage unit called Power pack unit using oil pressure for above function. Between turbine and Booster pump gear assembly is there. In 500 MW unit there are two similar TDBFPS located on turbine floor. TDBFPS have a big LCP (Local control panel) having facility for all operations of TDBFP.
Various system of TDBFP are discussed below : LUBE OIL SYSTEM
Lub oil system of both TDBFPS are provided with one Main Oil Tank each in which oil level is separately maintained. It has two AC AOPs, one JOP AC and one DC AOP connected to tank. Lub oil pressure is maintained at 3.0 Kg/cm2 on throttling after the pump oil at discharge pressure which is 9.0 Kg/cm2 is called control oil which is used as governing oil.
Lub oil after passing through coolers is led to various bearing of TDBFP system. DC AOP discharge oil is used on failure of AC AOPs bypass the coolers. During barring of TDBFP same lub oil at pr. 4.0 Kg/cm2 is used as power fluid in barring gear impellers. In the lub oil system provision is there to adjust the lub oil pr. by changing the recirculation flow.
SEAL INJECTION SYSTEM
Mechanical seals are provided on BP side for which continuous cooling is done by CEP
Mechanical seals are provided on BP side for which continuous cooling is done by CEP