2 _ Water System_44-64.pdf

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POWER PLANT SIMULATOR TRAINING INSTITUTE Bakreswar Thermal Power Project : WBPDCL

9 INTAKE PUMPS AND DAMs

1.0 BASIC OPERATIONAL PHILOSOPHY : 1.1 Supply of raw water to In Plant Raw Water Reservoirs:

During the months (9) when water will be available from Tilpara Barrage, Intake Water Pumps at TIPH will run to supply water to In-Plant Raw Water Reservoirs (Two Nos. Total capacity : 6,95,000 Cu.M) and maintain the maximum water level in the Reservoirs, irrespective of the number of units in operation.

1.2 Supply of Raw Water to Bakreswar Dam Reservoir: Only after filling up the In Plant Raw Water Reservoir, flow from TIPH to Plant Reservoirs will be diverted to Bakreswar Dam Reservoir (Cap.2,49,00,000 Cu.M) in order to create and auxiliary storage by supplying raw water fro TIPH. This change over of supply will be achieved by change over of valves installed in the Valve Room within the Power Plant Boundary 2.0 system description.

2.0 System description : Tilpara Intake Pump House is located about 100M away from the edge of Tilpara barrage pond. Six (6) nos. vertical wet pit type intake pumps are installed each in a separate sump in the pump house which is connected to the barrage pond. Outlets of all six (6) Intake pumps have been interconnected and finally raw water shall be discharged through two (2) nos. 900 NB. Feeder lines. This feeder lines are laid under ground from TIPH to plant boundary and over ground inside plant. The total length of 900NB each feeder line from TIPH to plant Reservoir is about 16KM. During pipe filling and also during normal supply, to prevent air locking twenty five (25) nos. of 200NB air release valves for each feeder line have been provided for escape of entrapped air. Four (4) nos. of 200NB Air Cushion Valves per feeder line have been provided at strategic points to avoid any vacuum pressure due to sudden stoppage of pumps or power failure during pump running.

Hydraulic system has been provided in the TIPH along with local control panel to operate two (2) nos. Butterfly valves located in the valve chamber on 900mm R.W. main outside TIPH. Office plate along with differential pressure transmitter has been provided in each feeder line outside TIPH. Rate of flow can be measured. An Integrator cum totalliser is also provided in the remote drive control panel to measure the total cumulative flow in each feeder line.

3.0 SPECIFICATION OF TIPH : Manufacturer : M/s. WPIL Ltd. Model No. : TM 24TC Type : Vertical Wet Pit Turbine Pump Rated capacity : 1950 Cu.M/HR. Rated TDH : 82.38 MWC Speed : 1487 RPM Motor rating : 610KW 4.0 SELECTION FOR OPERATING INTAKE PUMPS :

Out of six (6) pumps maximum four (4) pumps will be operating and two (2) will be kept as standby. The pump discharge will be through two (2) nos. feeder line. If one feeder line is down due to maintenance or any breakdown, maximum two (2) pumps will be operating. While four (4) pumps are operating, the following will be pumps discharge. 3,900 Cu.M/ hr per feeder line (Total 3,900*2 = 7 ,800 Cu.M/Hr.) while supplying raw water to Bakreswar Reservoir Dam. 3,120 Cu.M/hr per feeder line (total 3,120*2=6,240 Cum/hr.) while supplying raw water to Bakreswar Reservoir Dam.

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Though each pump is rated for 1,950Cu.M/ hr (normal), the pump is capable of supplying 70% to 165% of rated discharge. After starting of Intake pump, the pump discharge valve will start opening automatically with a time delay. Intake pumps are to be started one by one with a time gap of minimum 10 to 15 seconds.

5.0 INTERLOCKS & PROTECTIONS OF TILPARA INTAKE PUMPS: 1. Annunciations: 1.1 Sump level high 1 =62,39M 1.2 Sump level low = 60.20M 1.3 Sump level very low = 59.70M 1.4 Pump discharge header press. Low -7KSC 1.5 Pump discharge header press high = 11 KSC 1.6 Motor brg. (DE/NDE) temp. high = 70C 1.7 Motor brg. (DE/NDE) temp. very high = 80C 1.8 Motor winding temp. high = 100C 1.9 Motor winding temp. very high = 110C 2.0 Start Permissive:- 2.1 Sump level not low 2.2 Motor bearing & winding temp. not high 2.3 Discharge butterfly valve fully closed 2.4 No auto standby selection 2.5 No switchgear disturbance persisting 2.6 LOS released , Bkr. in service & DCP selector switch in normal position 2.7 Bus under voltage relay (86M) not operated 2.8 Lock out relay (86A) not operated 2.9 Interlock AC supply not failed at DCP 2.10 Trip ckt. Relay (95C) in reset condition 3. Interlocks & Protection trips : 3.1 Sump level very low 3.2 Motor brg. Temp. very high 3.3 Motor winding temp. very high 3.4 Bus under-voltage relay (86M) operated 3.5 Lock out relay (86A) operated 3.6 Off command from local /DCP 3.7 Discharge butterfly valve will close after pump trips/ made off 3.8 Auto standby pump starts if running pump trips. 3.9 Auto standby pump does not start if running pump is tripped manually from DCP 3.10 Pump does not start if discharge butterfly valve is not fully closed. 3.11 If all the three pumps in pipe line no.-1 are started, then preferential tripping of pump no.3 will

occur. Also. If all the three pumps in pipeline no.2 are started, then preferential tripping of pump no.6 will occur.

3.12 In running condition of pumps, if power pack valve of any pipeline gets closed, then all the pumps in that line will trip.

TRAVELING WATER SCREENS The traveling water screens are of self cleaning type to provide an effective and economic means of removal of debris, twigs, fibrous weeds, fish and innumerable number of suspended solids encountered from water which passes for suction of Tilpara Intake Pumps. Mode of operation : The operation of traveling water screens is totally manually controlled. The traveling water screen drives can be operated in either of the following two modes; From MCC

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From the local push button stations

Starting operation : The local difference between the upstream and the downstream of the traveling water screen shall be sensed by level indicators which have adjusted high and low set points. When the differential level across any TW screen reaches a preset (high) value, an audiovisual alarm will appear in enunciator for the particular screen. The operator has to acknowledge by pressing the accept push button and subsequently he has to start the screen wash pump by pressing the start push button for the individual pump. After starting of the screen wash pump, the TW screen shall be started with some time delay (to allow for sufficient water pressure developed in the header) by pressing the start push button for the individual screen. Both the screen wash pump and screen can be operated independently. The TW screen should be operated till the differential level across it reaches an allowable value or till the screen has rotated at least one and quarter turns. However, irrespective of differential level ; indications, all these screens should be run regularly for at least 30 minutes daily to prevent jamming of the rollers due to silt. Specifications: 1. Traveling water screen: : Manufacturer : Macmet Type : Dual flow (Motor operated) Capacity : 3,200Cu.M/hr. Net traveling speed : 2M/min. Drive rating : 15KW Chain pitch : 599 mm 2. Screen Wash Pump: Manufacturer : WPIL Type : Vertical Wet Pit Turbine Pump Capacity : 60 Cu. M/hr. Rated TDH : 60M WC Speed : 1483 RPM Motor rating : 18.5KW

OPERATIONAL WRITE UP BAKRESWAR INTAKE PUMP HOUSE (BIPH)

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BASIC OPERATIONAL PHILOSOPHY:

1.1 Transportation of Raw Water from Bakreswar Dam by pumps located in Bakreswar Intake pump house to Raw Water Reservoir inside the power plant will be done during those periods of the year when water from Tilpara Barrage is not available for operation of the power plant.

1.2 Transportation of Raw Water from Tilpara Barrage to Bakreswar Dam through valve room located inside the power plant when Tilpara pumps are in operation but water is not required at Raw Wager Reservoirs for operation of the power plant.

2.0 System description : Bakreswar Intake Pump House (BIPH) is located near Bakreswar Dam Reservoir outside the power plant. From Bakreswar Dam Reservoir two (2) nos. 1300NB pipe lines are connected with pump suction. From Bakreswar Dam Reservoir to pump suction pipe lines are laid underground. Two (2) nos. feeder lines to pump suction are interconnected by a short piece. Two (2) nos. Butterfly valves on each line have been provided to isolate a particular pump at the time of maintenance.

Two (2) nos. individual delivery lines are connected to two (2) nos. feeders lines. One motor operated butterfly valve in each line has been provided for isolation of pump delivery line when pump is not working. Two (2) nos. 900 NB recirculation line are connected to Bakreswar Dam Reservoir. One number butterfly valve for each recirculation line has been provided to isolate the line when water is being transported to power plant. Two (2) nos. 100NB drain valve for each feeder line have been provided to drain out water zone wise.

During pipe filling and also during normal supply, to prevent air locking five (5) nos 200NB air release valve per feeder line have been provided for escape of entrapped air.

One no. 200NB Air cushion valve per feeder line has been provided at strategic point to avoid any vacuum due to sudden stoppage of pumps or power failure during pump running.

Orifice plate along with differential pressure transmitter has been provided at each feeder line outside BIPH for measurement of rate of flow. An integrator cum totaliser is also provided in the remote drive control panel to measure the total cumulative flow in each feeder line.

3.0 SPECIFICATION OF BAKRESWAR INTAKE PUMPS :

Manufacturer : M/S. M&P Type : Horizontal Axial Split Casing double suction

centrifugal pumps. Rated Capacity : 8000 Cu. M. Rated TDH : 20 MWC Motor rating : 610KW Speed : 741 RPM Motor voltage : 6.6 KV

4.0 SELECTION FOR OPERATING BAKRESWAR INTAKE PUMPS: Out of two (2) pumps one shall be operating and other shall be kept as stand-by. In case of any breakdown or failure the stand-by pump shall start automatically or manually or manually depending on the mode of selection. The pump discharge shall be through two (2) nos. feeder lines.

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When one feeder line out of two lines is working, in case of second line breakdown or maintenance, the recirculation lines shall be kept open for recirculation of water to Bakreswar Dam. Though pump is rated for 8000Cu M / hr. (normal), the pump is capable of supplying 70% to 130% of rated capacity.

5.0 INTERLOCKS & PROTECTIONS FOR BAKRESWAR INTAKE PUMPS: 1.0 Annunciations:

1.1 Pump failure 1.2 Pump discharge header pressure low = 1.0 ksc. 1.3 Pump discharge header pressure high =3.0 ksc. 1.4 Motor winding temp. high = 100 C 1.5 Motor winding temp. very high = 110 C 1.6 Motor bearing temp. high = 70C 1.7 Motor bearing temp. very high = 80C 1.8 Full closing / opening of discharge valve 1.9 Pump suction pr. low = 0.3 ksc.

2.0 Start Permissive : 2.1 Suction pr. not low 2.2 Pp discharge valve fully closed 2.3 Motor bearing and winding temp. not high 2.4 LOS released bkr. in service 2.5 No switchgear disturbance persisting 2.6 Bus under voltage relay (86M) not operated 2.7 Trip ckt. Relay (95C) in reset condition 2.8 Lock out relay (86A) not operated 2.9 Interlock AC supply not filed at DCP 3.0 Interlocks & Protections Trips: 3.1 Motor winding temp. very high 3.2 Motor bearing temperature very high 3.3 Motor protection relay operated 3.4 Motor trip through LOS/ from DCP 3.5 Lock out relay (86A) operated 3.6 Bus under voltage relay (86M) operated 3.7 Discharge valve will close automatically after pump trips.

10 A BRIEF DESCRIPTION OF RAW WATER, CLARIFLOCCULATOR AND

FILTERED WATER.

Introduction:-

The water requirement of BkTPP is met from the existing Tilpara Barrage and Bakreswar Dam. The Tilpara Barrage is situated on the downstream of river Mayurakhsi of irrigation dept., Govt. of West Bengal, located about 16 kms. from plant site. A reservoir on river Bakreswar located about 3 kms. from the plant

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site has been created by WBPDCL by constructing a Dam to meet the requirements of the power plant during maintenance of Tilpara Barrage and other unforeseen eventualities. Intake pump house at Tilpara and Bakreswar as well as transportation system up to plant is for 5 x 210 MW units. The complete water transportation system is from Intake pump House at Tilpara and Bakreswar to power plant and inside the plant up to terminal points of different system & services consists of the following:-

1. Vertical Intake pumps and drives at TIPH. 2. Traveling water screens & screen wash pumps for Tilpara Intake pumps. 3. Horizontal Intake pumps & drives at BIPH. 4. Cross country under ground & over ground piping, valves etc. from Intake pump houses to Raw

water reservoirs inside plant. 5. Vertical pumps & drives for supplying Raw, clarified, filtered water inside the plant. 6. Low pressure & large dia piping systems including valves etc., 7. Necessary controls, instruments for operation of the pumps etc.,

Intake Pump Houses & Cross country pipelines:

Water for Bk.T.P.P. shall be normally available from Tilpara Intake Pump House for (9) nine months in a year. In the remaining period of 3 months, when water from Tilpara Barrage will be unavailable due to scheduled maintenance or any unforeseen eventualities, water shall be drawn from Bakreswar Dam. Water from Tilpara Barrage is received through Intake channels to the sump of the pump house. Travelling water screens along with seven wash system are installed upstream of the Intake pump at Tilpara to remove the debris, twigs, fibrous weeds, fish and suspended solids encountered from water.

There are six (6) nos. Intake pumps of vertical wet pit type, which discharge water to two (2) spirally welded mild steel pipelines.

These pipelines normally convey water to two (2) Raw water reservoirs located within the plant. When the Raw water reservoirs are full, water may be conveyed to Bakreswar reservoir through a diversion route extended to dam.

Two (2) horizontal pumps installed at Bakreswar Intake pump house draws water from Bakreswar reservoir by means of M.S. piping and supply water to two (2) Raw water reservoirs of the plant through the same set of pipelines through a valve room inside plant.

Along the cross country pipe lines there are existing railway lines, cable tracks,. H.T .line, local roads, a large number of storms water drains. Both the pipelines of 914 mm diameter are mainly underground (top of pipe is beyond 1 meter from the grade level) and the portion over Chandrabhaga Bridge and inside plant is above the ground. The pipelines above the ground is resting on concrete saddles. Necessary valves, fittings & accessories like air release valve, air cushion valve, Expansion joints, drain valves, orifices etc. have been installed on the piping system. All piping accessories were designed to with stand a pressure not less than the shut off head of the respective system.

Some Technical Data, Travelling Water Screen : Nos. of installed six (6).

Make - Macmet India Ltd. Type - Dual Flow type. Capacity - 3200 M3 / Hr. per screen Screen speed - 2 Mtr. / min. No. of screen Baskets 45 per T.W.S. Screen wire - SS-316 Size of mesh - 10 mm Sq.

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Dia of screen wire - 2 mm.

Screen Wash pump & drive: Nos. Installed - three (3). Motor Make - KEC. Volt - 415 V Rpm - 1470 KW - 18.5 Pump Make - WPIL Capacity 60 m3 / hr. Rpm - 1450 Stage - 7 TDH - 60 mtr.

Tilpara Intake Pump & Drives: Nos. Installed - six (6). Motor Make - KEC. Volt - 6.6 KV Rpm - 1487 KW - 610 Pump Make - WPIL Capacity 1950 m3 / hr. Rpm - 1487 Stage - 2 TDH - 82.38 mtr.

Raw water Reservoir : 2 Nos. Total Capacity 695000 M3

Bakreswar Reservoir (Dam) : Capacity 24.9 x 106 M3

Bakreswar Intake Pumps & Drives : Nos. Installed two (2). Motor Make - KEC. Volt - 6.6 KV Rpm - 741 KW - 610 Pump Make - Mather & Platt (I) Ltd. Capacity 8000 m3 / hr. Rpm - 741 Stage - 1 TDH - 20 mtr.

Raw Water transportation system :

In the system Raw water is pumped from Raw water reservoirs by means of 3(three) vertical wet pit Raw water Pump for i). Water pretreatment plant through underground pipelines terminating to an Inlet Flow Control Station. ii). Ash handling plant make up. Water pretreatment plant :

Raw water inlet flow control station to pre treatment plant (PTP) has two (2) parallel sections of 900 mm dia pipelines with control valves. Any of the parallel section shall be in service the other remaining stand by. Through this control station raw water enters into the stilling chamber. Chlorine is dosed at the stilling chamber to arrest the bacteriological growth and for the destruction of algae. Water from stilling chamber shall flow through three (3) identical channels. Each channel is provided with parshal type measuring flumes, have its individual float chamber with individual flow indicators. Individual isolating gates at the beginning and at the end have been provided so that any channel can be put into service. The three channels supply water to three clarifiers through flash mixers. Each channel has been provided with alum & lime dosing system for the treatment of water and shall pass to flash mixers, Flocculators & Clarifiers For chlorine dosing system, 2 nos. Vacuum type gaseous chlorinators, each of 20 kg/hr capacity have been provided. Liquid chlorine is available in chlorine drums, each of approx. 1 tonne capacity is used.

4 Nos. Alum solution preparation tanks with recirculating pumps, 2 nos. lime staking tanks with transfer pumps and 2 nos. Lime solution preparation tanks with recirculating pumps have been provided for dosing

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Alum & lime. Each tank is provided with mechanical motor driven agitators to keep the prepared solution in homogeneous suspension slurry. Flash Mixer:

Alum solution added to the raw water will interact and shall form incipient microfloculant particles of aluminum hydroxide and to ensure the uniform formation of microflocs, rapid mixing of the added chemical is done in Flash Mixers. There are three nos. Flash Mixers with isolation gates so that flow can be diverted through any Flush Mixers. Interconnecting Gates between flush mixers have also been provided. Each Flush Mixers is provided with motor driven agitators for rapid mixing of chemicals.

Clariflocculator : After rapid mixing of the raw water with the chemicals, it passes on to the Flocculation cum clarification unit (i.e. clariflocculator). The coagulant raw water is conveyed to the clariflocculator through the central inlet column. In the Flocculation chamber, the microflocs are mildly agitated by slowly revolving agitator paddles. The suspended particles along with water flows from the bottom of this chamber to the outer annular clarification zone. In the clarification zone, the suspended particles settle on the floor of the clarifier and the clear water overflows to the collecting Launders. Almost all the suspended matters present in the raw water thus settle on the floor of the clarifier. To remove these suspend particles, a rotating scraper has been installed in the clariflocculator. The scrapper has been fitted on a rotating bridge running on rail on the top of clarifier wall and pivoted on the central inlet column. The scrapper during rotation removes the settled solids on the floor of the clarifier to a collecting channel below the flocculator wall. Two separate pipelines with valves have been provided for collecting sludge in the sludge pit. When these valves are opened the suspended particles collected in the collecting channel discharge into the sludge pit under hydrostatic head. Besides manual desludging, desludging can be done automatically on each revolution of the clarifier Scraper Bridge with the help of a limit switch placed near the traction rail, a solenoid and a pneumatic actuated valve. The flow of sludge water through the sludge pipe can be adjusted to minimize the water loss with the help of a trumpet by lowering or rising) fixed near the top of water level of the clarifier. The clarified water collected in the launders of the three-clariflocculator flow through a common clarified water channel. The major part of the clarified water flows into the clarified water reservoirs. A small portion of clarified water is diverted to the rapid gravity filters for further treatment. Isolation Gates at the outlet channel of each clariflocculator and at the inlet of clarified water reservoir have been provided for any isolation if required.

Filtration System The clarified water diverted from the outlet channel flows to the filter bed inlet channel. There are three (3) nos. identical rapid gravity sand filters each having capacity of 150 m3 / Hr. supply filtered water to filtered water reservoirs. Each Gravity Filter bed is provided with sluice valves / Sluice Gates for inlet, outlet, Back wash tank inlet, drain and air inlet. The filter bed is provided with sand as filter media resting on graded layers of Gravel. At the bottom if gravel layers, a series of perforated lateral pipes connected to headers. This header have been provided for the dual purpose of collecting the filtered water during service operation and distribution of water from back wash tank during regeneration / back washing. The clarified water containing very small quantity of suspended floc particles passes through the sand where the floc particles are arrested. Thus filtered water is produced and which comes out through the outlet headers, connected with the lateral pipes. After filtration cycle the sand bed becomes clogged. The bed is cleaned by back washing. Back washing is done by scouring the sand with the help of compressed air from the bottom of the filter bed. The upward air bubbles loosen the filter media from the adhered floc particles; scour the media by rubbing action with one another. After the air scouring, filtered water at a high velocity is passes from the bottom so that the loosened suspended particles are carried out with this flow of water to the central channel and directed to waste through the drain valve. Thus the bed becomes ready for next operation.

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The water for back washing is available from overhead back wash Tank. This tank is filled time to time by a pipeline connected with the Drinking water pump (plant) discharge line. Each filter bed is provided with loss of head meter and one rate of flow meter. The loss of head meter indicates the head loss and the rate of flow water shows the flow in M3 / Hr. Each filter bed is provided with outlet control valve with a rate setter. This control valve automatically maintains a constant rate of filtered water output. This setting device can be set between 180 M3 / Hr. to 25 M3 / Hr. of flow. The filtered water thus produced is stored in two (2) reservoirs. One reservoir is used for supplying drinking water to plant and colony after chlorination for sterilization and the other is used for supplying water to DM Plant.

Clarified water Reservoir. On the clarified water reservoir two (2) Nos. service water pump (Plant), three (3) nos. Cooling Tower make up Pumps, three (3) nos. Ash Handling Plant make up pumps and two (2) nos. service water pumps (chemical) have been installed to supply water in the respective areas.

Sludge Pumps: The wastewater with sludge generated in pretreatment plant is the clarifier sludge water, the Filter bed back wash wastewater and small quantities of wastewater from drainage of chemical dosing etc. The sludge with wastewater is collected in a sludge-collecting chamber through drainage pits & inter connecting underground pipelines. This chamber has been provided with three vertical sump pumps for pumping the collected sludge water to a set of thickness. There are three sludge pumps. In the thickness the sludge will settle on the floor of the thickener & clear water shall over flow to an adjoining overflow sump. The discharge from sludge pumps can also be diverted to the stilling chamber, for increasing the sludge concentration of raw water, which will aid floc formation in the clariflocculator. This water is pumped to the raw water reservoirs by running overflow pumps for further use. Sludge collected at the Center of the thickener by a Mechanical Scrapper, is directly pumped from the bottom of the thickener to Centrifuges. For this 3 Nos. under flow pumps have been provided. Now due to very low sludge content in the system, centrifuges have been by-passed and under flow pumps discharge in drain. Some data

Raw Water Pump drive: Nos. installed Three Motor - Make - KEC. Volt - 6.6 Rpm. - 986 KW - 290 Pump - Make - W PIL Capacity- 2250 M3 / Hr. Head - 29.69 mtr. Rpm. - 986 Stage - I

Service water Pump Drive: Nos. installed Two (2). Motor - Make - KEC. Volt - 415 V Rpm. - 1483 KW - 75 Pump - Make - W PIL Capacity- 150 M3 / Hr. Rpm. - 1483 Stage - II TDH - 111.12 mtr.

Cooling tower make up Pump : Nos. installed Three (3). Motor - Make - KEC. Volt - 415 V Rpm. - 1483 KW - 160 Pump - Make - W PIL Capacity- 1400 M3 / Hr. Rpm. - 1483 Stage - I

Ash Handling Plant make up: Nos. installed Three (3). Motor - Make - KEC. Volt - 415 V Rpm. - 1465 KW - 37 Pump - Make - W PIL Capacity- 200 M3 / Hr. Rpm. - 1465 Stage - 4

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TDH - 27 mtr.

TDH - 42 mtr.

Service water pump for chemical house: Nos. installed Two (2). Motor - Make - KEC. Volt - 415 V Rpm. - 1440 KW - 7.5

Pump - Make - W PIL Capacity- 75 M3 / Hr. Rpm. - 1440 Stage - 5 TDH - 23 mtr.

Sludge Pump : Nos. installed Three (3). Motor - Make - KEC. Volt - 415 V Rpm. - 1440 KW - 7.5

Pump - Make - Sam Turbo Industry Ltd. Capacity- 120 M3 / Hr. Rpm. - 1450 Stage - I TDH - 12 mtr.

Over Flow Pump: Nos. installed Three (3). Motor - Make - KEC. Volt - 415 V Rpm. - 1500 KW - 7.5

Pump - Make - KBL. Capacity- 120 M3 / Hr. Rpm. - 1450 Stage - I TDH - 12 mtr

Under Flow Pump: Nos. installed Three (3). Motor - Make - KEC. Volt - 415 V Rpm. - 1500 KW - 2.2

Pump - Make - SAM TURBO Capacity- 120 M3 / Hr. Rpm. - 1450 Stage - I TDH - 12 mtr

Filter bed : Flow 150 M3 / Hr., per bed. Filter Media: 1st layer 50 x 25 mm Graded Gravel 150 mm. 2nd layer - 25 x 12 mm -do- - 100 mm 3rd layer 12 x 6 mm -do- - 100 mm 4th layer 6 x 3 mm -do- - 100 mm 5th layer Sand (Coarse) - 750 mm -1200 mm

Cariflocculator: Normal flow 1800 M3 / Hr. Maxim. Flow 2160 M3 / Hr. Clarfiier diameter 48 mtr. Approx. Flocculator dia 19 mtr. Bridge full rotation 48 minutes / rotation.

Drinking Water (Colony): Nos. installed Three (3). Motor - Make - KEC. Volt - 415 V Rpm. - 1485 KW - 90

Pump - Make - WPIL Capacity- 2000 M3 / Hr. Rpm. - 1485 Stage - 10 TDH - 100 mtr

Drinking water Pump (Plant): Nos. installed Two (2). Motor - Make - KEC. Volt - 415 V Rpm. - 1485 KW - 75

Pump - Make - WPIL Capacity- 150 M3 / Hr. Rpm. - 1485 Stage - 11 TDH - 111 mtr

Sketches of pipeline from TIPH to plant, a general arrangement drawing of vertical turbine pump and a block diagram of raw water from Intake Pump House to different termination point are enclosed for guidance.

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11 COOLING TOWER & CIRCULATING WATER SYSTEM

COOLING TOWERS:

The circulating water system supplies cooling water to the turbine condensers and thus acts as the vehicle by which heat is rejected from the steam cycle to the environment.

The circulating water system is called upon to reject heat to the environment in an efficient manner but is that also conforms to thermal discharge regulations. Its performance is vital to the efficiency of the power plant itself because a condenser operating at the lowest temperature possible results in maximum heat rejection.

As the cooling water takes the latent heat of steam in the condenser, the temperature of the water increases. The hot water coming cut of the condenser can not be used again in a closed system without pre-coding. This is because the hot water coming out if used again will not be able to absorb the heat as to reaches near to Ts, saturation temp. of steam at condenser pressure and the condenser vacuum can not be maintained. Therefore, it is absolutely necessary to pre-cool the water coming out of condenser before using again. The cooling systems which are commonly used in practice are:-

Cooling Tower:

Cooling tower is semi enclosed device for evaporative cooling of water by contact with air. The basic principle of cooling tower is evaporative condensation & exchange of sensible heat.

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WET TYPE COOLING TOWERS

Wet cooling towers dissipate heat rejected by the plant to the environment by these mechanisms:- (a) Addition of sensible heat to the air & (b) Evaporation of a portion of the recirculation water itself.

Wet cooling towers have a hot water distribution system that showers or sprays the water evenly over a latticework of closely set horizontal slats or bars called fill or packing. The fill thoroughly mixer the falling water with air moving through the fill as the water splashes down from one fill level to the next by gravity. Outside air enters the tower via louvers in the form of horizontal slats on the side of the tower. The slats usually slope downward to keep the water in. The intimate mix between water and air enhances heat and mass transfer (evaporation), which cools the water. Cold water is then collected in a concrete basin at the bottom of the tower where it is pumped back to the condenser. The new hot, moist air leaves the tower at the top. Wet cooling towers can be classified as either (a) Mechanical draft or (2) Natural draft cooling towers. Mechanical draft towers: In mechanical draft cooling towers, the air is moved by one or more mechanically driven fans. This speeds cooling & increases the efficiency of tower by increasing the air velocity over wet-surfaces and through the tower. Mechanical draft cooling towers can be divided into two types: (a) Forced draft tower - The fan is located at the base of the tower and air is blown by the fan up through

the descending water. (b) Induced draft towers: With this type air enters the sides of the tower through large openings at low

velocity and passes through the fill. The fan is located at the top of the tower, where it exhausts the hot, humid air to the atmosphere. Induced draft cooling towers are usually multicell with a number of fan stacks on top and come in various arrangements, rectangular, octagonal, circular etc.

Cooling towers are also classified by the motion of air in relation to the hot water. These are :-

Counter flow towers : Towers where hot water and air mix at 180 with air moving vertically through the packing are called counter flow towers.

Cross flow towers: In cross flow towers air and hot waters mix at 90 with air moving horizontally through the packing.

Natural draft cooling towers: Natural draft cooling towers use no fans. They depend for air flow upon the natural driving pressure caused by the difference in density between the cool outside air and the hot, humid air inside. These towers are of two types: (a) Hyperbolic & (b) Maintenance . Cooling Tower Performance :

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The rate of evaporation of water in cooling tower and subsequent reduction in water temperatures depends upon the following factors:- (a) Amount of water surface area exposed. (b) The time of exposure (c) Relative velocity of air passing over the water droplets formed in cooling tower. (d) The R.H of air and difference between the inlet air WBT and water inlet temperature. (e) The direction of air flow relative to water. Higher the surface area , more time of exposures lower relative humidity, higher difference between WBT of air and water inlet temperature and cross flow give effective cooling and reduce the tower size.

PSYCHROMETRIC TERMINOLOGY Cooling Tower Approach This is the difference between the cold water temperature and the wet bulb temperature of the outside air . Cooling Range - The range is the difference between the hot water temperature and the cold water temperature. Saturated air - This is air that can accept no more water vapour at its given temperature. A drop in that temp. would result in condensation and the new cooler air would also be saturated. An increase in temp. would make it unsaturated so that it could accept more water vapour. Relative humidity This is equal to the partial pressure of water vapour in air Press... , divided by the partial pressure of water vapour that would saturate the air at its

Temp. Psat at relative humidity is given by the symbol = Pv Psat. Specific humidity (humidity ratio) - It is defined as the mass of water vapour (all moisture) per unit mass of day air in a mixture of air and water vapour. It is represented by the symbol

W = mv ma

ma = mass of dry air , mv=mass of water vapour.

Dry Bulb Temperature (DBT) : This is the temperature of the air as commonly measured and used. Wet Bulb Temperature : This is the temperature of the air as measured by a psychomotor, in effect a thermometer with a wet gauge on its bulb , hence the name . Air is made to flow past the gauge. If the air is relatively dry, water would evaporate from the gauge at a rapid rate, cooling the bulb and resulting in a much lower reading than if the bulb were dry. If the air is humid the evaporation rate is slow and the wet bulb temperature approaches the dry bulb temperature. If the air is saturated i.e. =100%, the wet bulb temp. equals the dry bulb temp. Thus, for a given T, the wet bulb temp. is lower the drier the air.

Dew Point: The temperature below which water vapour in a given sample of air begins to condensate is called the dew point. It is equal to the saturation temperature corresponding to the partial pressure of the water vapour in the sample.

Degree of saturation : It is the ratio of actual specific humidity to the saturated specific humidity. It is represented by = W / WS.

Cooling efficiency : It is defined as the ratio or actual cooling of water to the maximum cooling possible . Actual cooling Tci - Tco = Max. cooling possible = Tci - Twb

Tci = water temp. C at cooling tower inlet. Tco = water temp. C at cooling tower outlet Twb = wet bulb temp C

LOSS OF COOLING TOWER :

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(a) Evaporation loss : Water that evaporate leaves the tower along with air in the form of water vapour. The evaporation loss is 1-1.5% of total circulating water.

(b) Drift loss : Drift is fine water particle entrained and carried over by the air. Drift eliminators are provided at exit to minimize the drift loss. Drift loss is 0.03% of total water.

(c) Blow down : To maintain a certain solid concentration, blowdown is necessary from the cold basin at the bottom of the tower. Blow down loss 1-1.5% of total circulating water.

Water treatment in cooling towers: The cooling of water in cooling towers is affected by partly evaporating the water and therefore salt concentrations in the remaining water goes on increasing. In closed cooling system, the water comes in close contact with air, acid, gasses and oxygen as it is passed through the cooling towers. The soluble acidic gasses and the air dissolve and concentrate in the circulating water. All the above causes scale formation and concession of metal parts. Hence, water treatment is necessary.

Blow down: Blow down or bleed off, the continuous removal of a portion of the water from the circulating system. Blow down is used to present the dissolved solids from concentrating to the point where they will form scale. The amount of blow down required depends upon the cooling range and the composition of make up water. Continuous blow down permits much better control of water conditions than intermittent blow downs.

Chemical Treatment: In some cases chemical treatment of the circulating water is not required if adequate blow down is maintained. In most cases, however, chemical treatment is required to prevent scale formation and corrosion. Sulphuric acid or one of the polyphosphates is mere generally used to calcium carbonate scale. Various proprietary materials containing chromates, phosphates or other compounds are available for corrosion control.

Slime, a gelatinous organic growth, algae, a green mass, may glow in the cooling tower or condenser or heat exchangers. There presence can interfere with cooling efficiencies. Proprietary compounds are available from water treating companies for the control of slime and / or algae, however, compounds which contain copper must be treated with care. Copper can accelerate corrosion of steel, iron, aluminium and galvanizing and should not be used in systems containing any of those materials. Chlorine and chlorine containing compounds are effective algaecides and slimicides but excess chlorine can damage wood and other organic materials of construction. If used, chlorine should be added as intermittently or shock treatment only as frequently as needed to control the slime and algae and free residual levels should not exceed one part per million parts water (1PPM).

Foaming : Heavy foaming sometimes occurs when a new tower is put into operation. This type of foaming generally subsides after a relatively short period of operation. Persistent foaming can be caused by the concentrations of certain combinations of dissolved solids or by combination of the circulating water with foam causing compounds. This type of foaming can sometimes be minimized by increasing the blow down, but in some cases from depressant chemicals must be added to the system.

Construction: Cooling tower is a large civil structure which is having a top basin, bottom basin, a cylinder located on the top basin and a number of louvers located on both sides of the structure. Class 1000 towers are constructed of reinforced concrete, cast in place concrete is used for the main columns and beams, lower columns end walls and fan decks. Pre-cast concrete is used for the hot water basin floor, fill support, beams, louvers, walk ways and eliminator supports. Within this civil structure, a number of components are placed as for example, fill, drift eliminators, target nozzles, flow control valves, splash boxes, gear reducer, drive shaft, FRP fan etc.

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Fill Fill is a medium by which more water surface is caused to be exposed to the air for a longer time. The heat transfer surface in the tower is actually the exposed surface of water. By using fill, surface of water can be increased. Thats why fill increases the rate and amount of heat transfer. Two types of fills are used :-

(i) Splash type fill & (ii) Film type fill.

Drift Eliminator :- Drift is water entrained by and carried with the air as unevaporated drizzle or fine droplets. This water is thus loss to the circulating water system and does not contribute to heat removal by evaporation. Drift is minimized by drift eliminators, which are baffles that come in one, two or three rows. The baffles force the air to make a sudden change in direction. The momentum of the heavier drops separate them from the air and impinges them against the baffles , thus forming a thin film of liquid that falls back into the tower. Water distribution system: The water distribution system dispenses hot condenser water evenly over the fill. There are several types , among them are (a) Gravity distribution, used mainly in cross flow towers, consists of vertical hot water risers that fed into an open concrete basin from which the water flows by gravity through orifices to the fill below. (2) Spray distribution, used mainly on counter-flow towers, has cross piping with spray downward nozzles. Another type is (3) Rotary distribution The basin: The cold water basin, situated beneath the tower collects and strains the water. Large utility tower basins are usually made of concrete.

Louver: Louvers are located on the side of the cooling tower along the length. It directs the flow of incoming air and ensures the water in the fill area does not splash outside the tower. These are pre-cast concrete panels supported at the ends by cantilever beams from the external louver columns.

Cylinder: The cylinder is a most important component of a cooling tower. Its height varies from 6 ft to 18 ft. It functions as a boundary for air movement through the tower and allows fans to move the required amount of air at significantly reduced fan power. Its venturi shape with close blade tip clearance promotes minimum entrance loss and produce optimum fan performance.

Flow control valves: From the condenser outlet line. CW water is lifted to the top basin of cooling tower through two legs. The CW water then allows falling on the top basin through flow control valves. In each cell there are two flow control valves by which flow or water can be regulated as per requirement. Valves are of disc. & stem type Flow pattern is 90. It helps uniform distribution of water on the top basin.

Splash box: Each flow control v/v discharges into wooden or concrete splash box located on the hot water basin. The splash box provides uniform water distribution of the operation of the basin.

Gear reducer: Since the fan RPM is very low, gear reducer have to be arranged with constant speed motor drive. Gear reducer also provides primary support for the fan & permit location of the motor outside the fan cylinder in a comfortable atmosphere for operation and maintenance. It is located at the centre of the cylinder and placed in suitable and special type of foundation. Reduction gear is such that horse power is supplied at optimum fan speed. Gears operate in an oil bath and the lubrication system performs well in both forward and reverse operation. The gear reducer unit is equipped with remote sight gauge and drain lines which permits constant check up of oil from outside.

Drive shaft :- The drive shafts transmits power from the motor to the gear reducer. It is manufactured from the stainless steel tube. The drive shaft is dynamically balanced to minimize vibration. They accept considerable torque loads without distortion and misalignment. They are full floating shaft with non-lubricated couplings at both ends. No intermediate coupling is used.

Fan : Fans are the major mechanical components of cooling tower. The diameter of the fan varies depending upon the capacity of the tower. Fans are located on the output shaft of the gearbox and inside the cylinder.

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Blade material is selected on the basis of environment in which it will work at BkTPP; blade material is glass re-enforced polyester (GRP).

INTERLOCKS AND PROTECTION OF C.T. FAN AT BKTPP.

START PERMISSIVE : (a) Gear box oil level is normal. (b) No overload trip & vibration high trip is persisting. (c) Control fuse O.K. & LOS released (d ) DCP control supply, control transformer A/B & 415V 1PC bus A/B normal. PROTECTIONS : (a) Overload (b) Control fuse blown (c ) Vibration high (d ) Gear reducer oil level low.

CIRCULATING WATER SYSTEM (CW SYSTEM)

At full load operation of the unit about 440 ton/hr. of steam is exhausted into twin surface condenser. About 27000T/hr. of cooling water is required for condensing this exhausted steam. The cooling water is supplied by three (3) nos. (2X50%, i.e. two running one standby at 100% ) load vertical mixed flow pumps of 15750T /hr. capacity each at 25.5 MWC head.

CW Pump :- CW pump of type CW1QB8GOA is a mixed flow pump having a semi open type impeller. The pump is a vertically mounted, non-pull out type. The pump is having its own thrust bearing mounted as the base plate and the pump is connected to the drive motor through a flexible coupling. The pump is suitable for starting with disch. v/v closed . However, it is suggested to start the pump with partial open v/v condition as the vibration and noise levels are very high at flows below 25% of rated flow. In case of pump starting with closed v/v , care to be taken to open the v/v as quickly as possible. In any case it shall be tripped if the disch v/v fails to open beyond 10 min. After the pump starting.

The pump is supported and anchored at the operating floor. The foundation plates are adequately designed for taking all the loads. The thrust at the disch. Elbow will be taken by thrust block.

DESCRIPTION :

Impeller is a semi open type, mixed flow dynamically balanced mode up of stainless steel type CF8M. Hydraulic axial thrust developed by the impeller and the weight of the rotor will be taken up by the thrust bearing. The impeller does, not have hydraulic thrust balancing holes . Pump casing: Pump casing is also known as diffusers and it converts the kinetic energy of the fluid into pressure energy. This is gray iron casting. It also houses the bearing body, into which the cutlass rubber bearing is fitted in. BELL mouth Bell mouth is designed to ensure a smooth, guided accelerated flow of water into the impeller. It is made up of gray iron. Column Pipe - Column pipe connects the pump casing and the discharge elbow. Water is lifted from the pump casing through this pipe. This also houses the guide bearings for the shafts. The entire length of column pipe is split into three parts. These parts are made up of MS plate of IS 2062. Discharge Elbow: It deflects water from vertical column pipe to the horizontal discharge piping. This also houses stuffing box where the shaft sealing is achieved through gland packing. It is made up of MS plates of IS2062. Suspension Suspension offers a base for the motor stool and the pump thrust bearing. This rests on the foundation frame at the operating floor and is connected to the discharge elbow at its lower end.

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Shafts: The entire shaft is split into four parts, namely pump shaft, intermediate shaft, head shaft and drive shaft. These four shafts are joined together by means of three muff couplings (muff coupling is a rigid coupling. A sleeve is fitted with keys with both the shafts to be coupled). Impeller is mounted auto the pump shaft at its bottom end and is firmly secured in position by means of a nut and lock washer. The drive shaft is connected to the motor shaft at its top end through a flexible coupling. All the four shafts are made up of high tensile stainless steel type 410 forgings. The miff couplings between the shafts are made up of SS type 410 forgings.

MAIN COUPLING -The main coupling that connects the drive shaft and the motor shaft is a flexible membranes type coupling having considerably high degree of flexibility for mis-alignment.

SPHERICAL ROLLER THRUST BEARING Spherical roller thrust bearing is designed for taking the hydraulic axial thrust of the impeller and also weight of pump rotating parts. It is spherical roller type, oil immersed bearing. Oil is cooled by external cooling water circulated through a cooling coil provided in the bearing pan. The bearing is provided with one oil level indicator, one local mounted contact thermometer and two nos. simplex RTDs for temperature monitoring.

NON REVERSIBLE RATCHET Non reversible ratchet prevents the reverse rotation of the stand by pump rotor in the event of back flow from the running pump.

A motor operated discharge butterfly valve is provided on the discharge of each pump, which is interlocked to open and close automatically on starting and stopping of the pump p/p respectively. The Pps are started from the local LOS / control panel in the CW pump house.

All the pumps discharge into the common 2.3M dia CW header supplying water to the twin surface condenser. The normal inlet and outlet of the condenser are through bottom and top respectively by two branch offs of 1600NB each from above header. The inlet and outlet are provided with motor operated butterfly v/vs. All the four v/vs of condenser I/L & O/L can be operated individually by local push button or from control room. The hot water O/L from condenser along with hot water from auxiliary coolers is led through a 2400NB header to cooling tower of respective units for cooling by means of two nos hot water risers of 1700WB size each. Each hot water riser distributes hot water to the hot water basin through two nos. flow control v/vs at the deck level. Number of flow control v/vs for each cell is 4 nos. of 500 WB size. One number butterfly v/v is provided on each hot water riser near ground level to facilitate isolation. The coal water from each cooling tower is led by gravity to CW pumps sump (Feed Pool) through individual RCC duct. Two bar screens in series are provided downstream of cooling tower cold water outlet basin to arrest any flowing matter in water. A sludge pump is provided in each C.T. basin to dislodge the sludge deposited in CT basin and dewatering the C.T. basin for cleaning etc. The O/L of sludge Pp is in plant drain. The cold water from CW sump is re-circulated to condenser for cooling. Make up water is provided in feed pool by means of CTMU Pp (cooling tower make up Pp) at clarified water Pp house.

OPERATION START PERMISSIVES

(a) Bkr is in service and no switchgear disturbance is persisting. (b) Motor protection relay not operated and no trip command existing (c) At LCP selector switch is in MAN / Auto mode. (d) Motor winding temp not high ( < 100C) (e) Pump / Motor brg. Temp. not high (

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PROTECTION TRIPS : (a) Motor electrical protection operated (earth fault, short ckt., stalling, (-)ve phase sequence and over

current). (b) Motor winding temp. V. high (> 130C ) (c) Bus under voltage (d) BTS (BUS TRANSFER SYSTEM) trip command (e) Lock out relay (86) operated (multiplier at DCP) (f) Trip command from LCP (g) Pump / Motor brg. Temp. v. high (> 80 C ) (h) Pump / Motor bearing vibration v. high (i) Pump thrust bearing temp. v. high (> 80 C ) (j) Disch. v/v fails to open 10 with a time delay of 12 secs. (k) Sump level v. low (71.1M)

Auto operation & Interlocks: (a) In auto standby pump will take start (provided start permissive are fulfilled) at the following

conditions : (i) Any other Pp trips (ii) Common disch. Hdr. Pr. low ( < 1.2 ksc.)

(b) After pump start disch. v/v will open automatically. (c) Discharge v/v will fully open when discharge header pressure becomes adequate (d) Discharge v/v will close fully with Pp stop / trip. (e) Due to 10 opening failure of disch. V/v, when a pump trips or when a pump trips for another

reason further operation said p/p operation of its disch. v/v are protected unless reset is done by closing LOS of pump discharge. v/v.

Starting Procedure : Prestart checks

(a) Feed Pool level normal (b) Thrust bearing oil level normal (c) 6.6KV supply to motor is healthy i.e. bkr. rack in, D.C. on and normal mode selected to run the

pump form LCP C.W. pump may run from LOS keeping the selector switch in bkr. in trial mode. In that case some protections are bypassed. All the electrical relays in reset condition.

(d) 415V supply to disch. v/v is healthy, i.e. fuses inserted isolator kept on and normal mode selected for remote (i.e. LCP) and auto operation and trial mode for LOS operation.

(e) LOS (lock out switch) of pump, motor and disch. v/v are normal. For starting the 1st pump following points to be noticed. (i) Condenser I/L & O/L v/vs are in full open condition (ii) Cooling tower hot CW supply line v/vs are open. (iii) All air vents in CW line are in open condition and all air release relief v/vs in disch. Piping is functioning. (iv) Condenser water box vents are open and drains closed (v) All instrument root v/vs are open (vi) CT make up system available.

Before starting 1st pump priming and pressurizing to be done by back charging the condenser from ACW water. If back charging is not possible (i.e. ACW is not running, then open the disch. v/v 5 10 locally before starting the pump . Give start command to the pump (from LCP disch. v/v will automatically open by 10 to prime the CW disch. Hdr.. After system is primed and pressure is built up in disch. hdr. adequately CW system trouble alarm will reset at >1.2ksc & discharge butterfly v/v operation should be regulated to control flow into the main. After starting 1st Pp , the 2nd CW can also be started ( in this case check additionally that the Pp is not rotating in reverse direction).

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After establishing circulating water flow through cooling tower control the flow in each cell by individual flow control v/vs to its design flow. Lock the v/vs at that position. C.T. fans may be started after 30 mins. CHECKING AFTER START :

(a) Pump discharge pr. is normal (>1.2ksc) (b) Discharge v/v has been opened fully (c) No abnormal sound and vibration (d) Check the auxiliary cooling water flow to the thrust and journal brg. (e) Motor bearing and thrust brg. Temp. is normal (f) Motor current is normal

After starting the 1st Pp close gradually the water box I/L & O/L vents when water is enough quantity flows out. SPECIFICATIONS :

Cooling Tower

MANUFACTURER : PAHARPUR COOLING TOWER LTD. TOWER MODEL : 1513-10 TYPE : INDUCED DRAFT CROSS FLOW

HAVING SPLASH TYPE FILL. RATED WATER FLOW THROUGH : COOLING TOWER (CM/H) : 33000 DESIGN WET BULB TEMP. ( AMBIENT ) (C) : 29 DESIGN I/L AIR WET BULB TEMP. (C) : 30 DESIGN COOLING RANGE (C) : 8.3 MINIMUM APPROACH TO DESIGN : 3.76 (INLET AIR WET BULB TEMP.

THAT CAN BE ACHIEVED BY (C)

ADJUSTING FOR BLADE PITCHES (TO DRAW FULL MOTOR HP)

EVAPORATION LOSS AT RH OF 100% (AT DESIGN) PER CELL ( CU.M/HR)

: 44.68

MAXIMUM DRIFT LOSS ( AT DESIGN) PER CELL (CU M./HR)

: 0.66

AMOUNT OF BLOWDOWN PER CELL @ DESIGN ( BASED ON FIVE (5) CYCLES OF CONCENTRATION (CUM/HR.)

: 10.51

AMOUNT OF COOLING TOWER MAKE UP REQUIRED PER CELL ( BASED ON FIVE (5) CYCLES OF CONCENTRATION ) ( CUM/ HR)

: 55.85

COOLING TOWER MATERIAL & CONSTRUCTION : CASING , SUPERSTRUCTURE , PARTITION WALL : RCC LOUVERS : RCC CELL PARTITION WALLS : RCC HOT WATER DISTRIBUTION BASIN : PRECAST CONCRETE WITH PP NOZZLES HOT WATER DISTRIBUTION NOZZLES & SPLASH

PLATES : POLYPROCYLENE (PP)

COLD WATER BASIN : RCC COLD WATER CHANNEL : RCC CELLS

NUMBER OF CELLS REQUIRED TO ACHIEVE RATED PERFORMANCE

: NINE (9)

TOTAL NO. OF CELL OFFER4ED : 10( 9 RUNNING -1 STANDBY) LENGTH & WIDE , METRE / CELL TOWER : 13 X 25.72 TOTAL LENGTH (METRE) : 130.4 TOTAL WIDTH (METRE) : 25.72

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LOUVER HEIGHT & ANGLE WITH HORIZONTAL (METRE-DEGREE)

: 10.67M/39.8

HOT WATER I/L : NUMBER : 2(TWO) NOMINAL DIAMETER : 1700NB FLOW CONTROL VALVE

TYPE : PAHARPUR TYPE ( HORIZONTAL FLOW CONTROL VALVE )

SIZE : 500 NB NUMBER OFFERED : 4(FOUR) PER CELL FILL & FILL SUPPORTS : FILL TYPE : PVC SPLASH TYP(FIRE RETARDANT

TYPE) MATERIAL : EXTRUDED PVC ARRANGEMENT OF FILL / SPLASH BARS : HORIZONTAL / PARALLEL TO AIR

FLOW DRIFT ELIMINITORS : NUMBER OF PASSES : THREE (3) TYPE : CELLULAR PVC TYPE MATERIAL : PVC FANS

MANUFACTURER AND MODEL NO. : PAHARPUR TYPE HP-6-8 TYPE : AXIAL FLOW PROPELLER TYPE NUMBER FURNISHED : ONE PER CELL DIAMETER (METRE) : 10 NUMBER OF BLADES : 8(EIGHT) FAN SPEED (RPM) : 98 BLADE MATERIAL : FIBRE GLASS REINFORCED

POLYESTER (FRP) GEAR REDUCER : MANUFACTURER AND MODEL NO. : PAHARPUR SERIES - 36 TYPE : SPIRAL BEEVEL CUM HELICAL NUMBER OF REDUCTIONS : 2(TWO) REDUCTION RATIO : 14.84:1

DRIVE SHAFT TYPE : TUBULAR , FULLY FLOATING NON-

LUBRICATED TYPE MOTOR RATINGS : 110 KW 4 POLE METHOD OF CONNECTION TO DRIVEN EQUIPMENT : FLEXIBLE COUPLING CLASS OF INSULATION : CLASS F.

CIRCULATING WATER PUMPS :

MANUFACTURER : BHEL CAPACITY (M/ HR.) : 15750 TOTAL DYNAMIC HEAD

(MLC) : 25.5

SHUT OFF HEAD (MLC) : 48 PUMP RATED SPEED (RPM) : 490 PUMP DUTY : CONTINUOUS PUMP TYPE : MIXED FLOW PUMP DESIGN : NON-PULLOUT BELOW FLOOR DISCHARGE IMPELLER TYPE : SEMI OPEN NUMBER OF STAGES : ONE

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