SWITCH YARD

2X660MW SUPER CRITICAL THERMAL POWER PLANT AT

THARANGAMBADINAGAPATTINAM DIST.TAMIL NADU

CONSULTANT

DEVELOPMENT CONSULTANTS PRIVATE LIMITED 191, ANNA SALAI, CHENNAI - 600006

BID SPECIFICATION NO. : 11Z02SPCG001

MAIN PLANT PACKAGE [[BBOOIILLEERR TTUURRBBIINNEE GGEENNEERRAATTOORR]]

VOLUME : II – C

TTUURRBBIINNEE GGEENNEERRAATTOORR,, AAUUXXIILLIIAARRIIEESS AANNDD OOTTHHEERR FFEEEEDD CCYYCCLLEE EEQQUUIIPPMMEENNTT

CPCPL-Super Critical TPP-Tharangambadi [2 x 660 MW] Main Plant Package CONTENTS DCPL-11Z02

MMAAIINN PPLLAANNTT PPAACCKKAAGGEE

[[BBOOIILLEERR TTUURRBBIINNEE GGEENNEERRAATTOORR]]

OVERALL CONTENTS VOLUME-I : COMMERCIAL & GENERAL CONDITIONS OF CONTRACT VOLUME-II : TECHNICAL SPECIFICATION VOLUME-III : BID PROPOSAL SHEETS [TECHNICAL PART]


CONTENTS VOLUME : II TECHNICAL SPECIFICATIONS VOLUME II-A : LEAD SPECIFICATION VOLUME II-B : SPECIFICATIONS FOR STEAM GENERATOR & AUXILIARIES VOLUME II-C : SPECIFICATIONS FOR TURBINE-GENERATOR, AUXILIARIES &

OTHER FEED CYCLE EQUIPMENT VOLUME II-D : SPECIFICATIONS FOR POWER CYCLE & OTHER PIPING,

VALVES & SPECIALTIES VOLUME II-E : SPECIFICATIONS FOR CONTROLS & INSTRUMENTATION VOLUME II-F/1 & : SPECIFICATIONS FOR ELECTRICAL EQUIPMENT & VOLUME II-F/2 ACCESSORIES [IN TWO VOLUMES] VOLUME II-G : SPECIFICATIONS FOR ELEVATORS VOLUME II-H : SPECIFICATIONS FOR MAIN, AUXILIARY & CLOSED CIRCUIT

COOLING WATER SYSTEMS & ACCESSORIES & MISCELLANEOUS SYSTEMS.

VOLUME II-I : FLUE GAS DESULPHURISATION (FGD) VOLUME II-J : TENDER DRAWINGS

VOLUME : II-C

TECHNICAL SPECIFICATIONS FOR

TURBINE-GENERATOR, AUXILIARIES AND OTHER FEED CYCLE EQUIPMENT


CONTENT VOLUME : II-C SPECIFICATIONS FOR TURBINE-GENERATOR,

AUXILIARIES & OTHER FEED CYCLE EQUIPMENT SECTIONS DESCRIPTION SECTION-I : TURBINE-GENERATOR AND AUXILIARIES SECTION-II : FEED WATER HEATERS & DEAERATOR SECTION-III : POWER CYCLE PUMPS, DRIVES & ACCESSORIES SECTION-IV : CONDENSER & AIR EXTRACTION SYSTEM SECTION-V : TURBINE OIL PURIFICATION SYSTEM SECTION-VI : CONDENSATE POLISHING SYSTEM SECTION-VII : CONDENSER TUBE CLEANING SYSTEM

VOLUME : II-C

SECTION-I

TURBINE GENERATOR AND AUXILIARIES


CONTENT CLAUSE NO. DESCRIPTION PAGE NO. 1.00.00 GENERAL INFORMATION V.IIC/S-I : 1 2.00.00 CODES & STANDARDS V.IIC/S-I : 1 3.00.00 EQUIPMENT AND ACCESSORIES TO BE FURNISHED V.IIC/S-I : 2 4.00.00 GENERAL PERFORMANCE REQUIREMENT V.IIC/S-I : 5 5.00.00 TURBINE TYPE AND RATING V.IIC/S-I : 7 6.00.00 TURBINE DESIGN AND CONSTRUCTION V.IIC/S-I : 8 7.00.00 GENERATOR AND AUXILIARY SYSTEM V.IIC/S-I : 22 8.00.00 GENERATOR AND ACCESSORIES V.IIC/S-I : 25 9.00.00 INSTRUMENTATION AND CONTROL V.IIC/S-I : 36 10.00.00 TESTING AND INSPECTION V.IIC/S-I : 37 11.00.00 DATA, DRAWINGS AND INFORMATION REQUIRED V.IIC/S-I : 43 ATTACHMENT ANNEXURE-I SPECIFIC DESIGN CRITERIA FOR TURBINE GENERATOR SET V.IIC/S-I : 47

CPCPL-Super Critical TPP-Tharangambadi [2 x 660 MW] Main Plant Package

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VOLUME : II-C

SECTION-I

TURBINE GENERATOR AND AUXILIARIES

1.00.00 GENERAL INFORMATION

Each 660 MW super-critical Steam Turbine shall be connected to a Steam generator. The steam turbine shall be supplied with steam for generation of power and for regenerative feed heating through uncontrolled extraction points. Determination of number of extraction points, turbine stages for such extraction and final feed water temperature shall be based on the optimization study by the Bidder considering turbine manufacturer's proven standard design. Bidder to ensure suitability of final feed water temperature for steam generator at all loads.

The Steam Turbine shall be directly coupled to a synchronous generator for

developing electrical power. All the auxiliaries for Turbine-Generator shall be provided. The specific design criteria for Turbine have been presented in attached Annexure-I.

This section of the specification shall be read in conjunction with other

volumes of the specification as appropriate and the equipment offered shall meet the requirements as spelt out therein.

2.00.00 CODES AND STANDARDS 2.01.00 In addition to the requirements spelt out in Section-IV of Vol. IIA the

equipment to be provided under this section shall specifically conform to the latest editions of the following codes, standards, specifications and regulations:

2.01.01 PTC-6 : ASME Performance Test Codes for Steam Turbines. 2.01.02 IEC:34-1 : Specification for rotating electrical machines. 2.01.03 IEC:34-3 : Specific requirement for turbine-type synchronous

machines. 2.01.04 IS:7132 : Guide for testing synchronous machines. 2.01.05 IEC:34-2 : Method for determining losses and efficiency of rotating

electrical machinery from test. 2.01.06 IEC:34-4 : Methods of determining synchronous machine quantities

from test. 2.01.07 IEC:34-5 : Classification of degree of protection provided by

enclosures for rotating machines.


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2.01.08 IEC:34-6 : Methods of cooling rotating machinery. 2.01.09 IEC:34-8 : Terminal marking and direction of rotation for rotating

machines. 2.01.10 IS:3003 : Specification for carbon brushes of electrical machine. 2.01.11 ASME-TDP1 : Prevention of water damage to steam turbines. (Part-I) 2.01.12 IBR : Indian Boiler Regulations. 2.01.03 Applicable Japanese Standards (JIS). 3.00.00 EQUIPMENT AND ACCESSORIES TO BE FURNISHED Each turbine generator (TG) unit shall be provided with the following

equipment and accessories. 3.01.00 Steam Turbine Generator with Auxiliaries 3.01.01 Steam turbine from inlet of emergency stop valve up to exhaust flange

including all extraction valves and interceptor valves complete with all integral accessories.

For main steam and hot reheat line, scope of Turbine proper shall be limited

up to and including the ESV and the interceptor valve near the turbine. For cold reheat line, scope of Turbine proper shall be limited up to and including the turbine exhaust.

3.01.02 Complete turbine integral piping and other piping including all valves

(isolating, regulating, non-return, hand-operated and/or pneumatic, motorized), actuators, air vents, safety valves, drains, hangers, supports, anchors and other fittings.

Power operated (hydraulic/pneumatic) quick closing non-reverse flow valves

for each extraction line and cold reheat line. 3.01.03 60% BMCR capacity latest state of the art international technology aided High

Pressure (H.P) and corresponding Low Pressure (L.P) steam by-pass valves, and complete spray system, control valves, de-superheating devices, valves, controls and instrumentation etc.

3.01.04 Duplex type Turbine digital electro hydraulic (DEH) governing system

including governors, load limit device, low vacuum tripping device, bearing protective devices, solenoid trip etc., as specified hereinafter and all equipment mounted/local instruments, pressure, temperature, level switch, primary sensing device etc., as required.

3.01.05 Turning gear equipment and provision for manual barring. 3.01.06 Complete high pressure control oil and lubricating oil systems with tanks,


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shaft or Motor driven oil pumps(as per standard and proven manufacturer practice) and other necessary pumps and drives, lube oil coolers, all connected piping, valves, filters, strainers, vapour extractors, instruments etc.

3.01.07 Gland steam sealing system with steam pressure regulators, desuperheater,

all piping, valves, specialties and associated instruments and also gland steam condenser, vapour extractors etc.

3.01.08 All piping, valves and accessories for turbine flanges, casing and stud heating

steam as recommended by Bidder. 3.01.09 Turbine local gauge board. 3.01.10 Steam turbine exhaust hood spray system including nozzles, power operated

valves and specialties, hangers, supports and insulation, instruments etc. 3.01.11 Turbine drain system complete with integral piping, valves, fittings, Motor

Operated (M.O) valves, hangers, supports and insulation. Wet steam washing system for Turbines, if recommended by the bidder.

3.01.12 Blanking discs for emergency stop and reheat interceptor and control valves

and special bonnets, as required for steam blow out. Provision for steam blow-out pipe connection with cold Reheat line non-return valve.

3.01.13 Turbine exhaust casing pressure rupture diaphragms. 3.01.14 DC solenoid operated vacuum breaker valve with air lock relay and with

provision for remote operation . 3.01.15 Auxiliary turbine (s) for boiler feed pump drive along with complete auxiliary

turbine inlet and outlet steam systems; including lube oil system. 3.01.16 Generator with all its integral accessories and supervisory instruments. 3.01.17 Coupling between turbine and generator including coupling guard as

necessary. 3.01.18 Excitation system including AVR, field suppression/flashing equipment,

inter-connecting cables/bus duct. 3.01.19 Generator hydrogen system equipment and controls including associated

piping, valves, coolers and control panels as required and necessary, CO2 system manifold, piping, including drier and monitoring instruments.

3.01.20 Stator water-cooling system complete with associated piping, valves, coolers

and control panels as required and necessary. 3.01.21 Hydrogen seal oil system complete with pumps, piping, valves, coolers (if required by bidder), all control and annunciation instruments and panels etc. 3.01.22 Generator terminal bushings and current transformers. 3.01.23 Generator hydrogen gas cooling and purge systems.


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3.01.24 Demineralised closed cycle cooling water supply and return piping along with valves, drains, vents etc. for cooling purpose of all coolers under Turbine Generator Package.

3.01.25 ACW supply & return piping along with necessary valves, drains, and vents

etc. for cooling purpose of TG-PHE and PHE for TG-Auxiliaries cooling are under Turbine generator package.

3.01.26 All control gears for turbine and generator whether specifically mentioned or not. 3.01.27 Thermal insulation for turbine, auxiliary equipment and piping covered under

this turbine generator section. 3.01.28 Acoustic cladding for complete steam turbine generator units along with

turbine generator hood. 3.01.29 Interconnecting pipes, valves and supports with flash vessels, drain tanks etc.

for recoverable drains of the cycle including gland sealing, spindle leak-off etc.

3.01.30 The scope of Instrumentation & Control shall include but not be limited to the

following, as elaborated in Vol-II-E a) Complete hardware and software, Push button stations, Hand-auto

stations, Status indication for turbine generator control systems. b) Turbine Stress Evaluator. c) Automatic Turbine Run-up System. d) Sequential Turbine Testing System. e) Turbine Protection and Interlock System. f) Turbine Supervisory System. g) Electro-hydraulic Governor

h) HP-LP Bypass Control System 3.02.00 Miscellaneous Items 3.02.01 All sole plates, sub-sole plates, shims, jack-screws and wedges, as required,

to set and align the turbine generator unit etc. 3.02.02 All foundation frames/base plates, anchor bolts, sleeves, nuts etc. for all

equipment under this section. 3.02.03 Special lifting slings, lifting beams etc. for erection and maintenance of the

turbine cylinders and rotors, generator rotor, bolt-heating device, tongue wrenches etc.

3.02.04 Suitable lifting attachments i.e., lifting lugs, eye bolts, slings, etc. for all

equipment to facilitate erection/maintenance.


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3.02.05 Suitable temporary arrangement shall be made during erection for installation

of generator stator. 3.02.06 A reserve feed water tank-cum-condensate surge tank of adequate capacity

for each unit, with provision for filling, supplying make-up to condenser hot well, receiving dumped condensate, supplying gland sealing water, overflow and vent through seal pots, etc. Such a tank shall be considered as an optional item for the proposed package.

4.00.00 GENERAL PERFORMANCE REQUIREMENT 4.01.00 Heat Rate will be defined as follows: M1xH1+M2x(H3-H2)-M3xH4+MmxHm-MsxHs+Mrx(H3-Hr) HR = ----------------------------------------------------------------------------------------- Pg where HR : Heat Rate Kcal/kWHr M1 : Live steam entering the turbine stop valve including any live steam supplied to valve stems, ejectors etc. Kg/Hr M2 : Steam flow from turbine to reheater Kg/Hr M3 : Final Feedwater Flow at final Feedwater HTR Outlet Kg/Hr Mm : Make Up Flow to Condenser Kg/Hr Ms : Superheater Spray Flow Kg/Hr Mr : Reheater Spray Flow Kg/Hr H1 : Enthalpy of live steam Kcal/kg H2 : Enthalpy of cold reheat steam Kcal/kg H3 : Enthalpy of hot reheat steam Kcal/kg H4 : Enthalpy of feed water at final feed water heater outlet Kcal/kg Hm : Enthalpy of Make Up Water Kcal/kg Hs : Enthalpy of Superheater Spray Water Kcal/kg Hr : Enthalpy of Reheater Spray Water Kcal/kg Pg : Electrical power generated at generator terminal less the power taken by the Exciter KW


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The heat cycle will include steam turbine driven boiler feed pump and its effect in the heat rate both as regards the heat for turbine drive and gain of feed water enthalpy. In case the Bidder anticipates the use of spray and make up water during the performance guarantee test, the corresponding heat rate shall be guaranteed and the related heat balances shall be furnished with the bid.

The Bidder shall furnish correction curves applicable for heat rate calculations under varying parameters of steam (pressure and temperature), reheat circuit pressure drop, inlet temperature of condenser cooling water and condenser vacuum.

4.02.00 The Bidder shall state the maximum continuous capability of the Turbine with

valves wide open (VWO) and indicate the maximum flow passing ability of the machine corresponding to rated steam parameter and at rated condenser vacuum at 77 mm Hg absolute.

The TG shall generate 660MW under rated steam conditions, specified worst condenser pressure, 3% cycle make up and 47.5 Hz grid frequency.

4.03.00 The unit shall be capable of operating with all the H.P. heaters cut-out and no

extraction steam supply to them. The bidder shall indicate the maximum output the unit is capable of delivering continuously under such condition.

4.04.00 The turbine generator units shall be designed to operate satisfactorily under

prevailing climate. They shall be suitable for indoor installation on reinforced concrete foundation mounted on springs and dampers.

4.05.00 The turbine generator unit shall comply with general requirements and

standards of relevant latest versions of IEC & IEEE or their approved equivalents or as per the suppliers standard practices to be mutually agreed between the Bidder and Purchaser and the additional requirements as specified hereinafter. All materials, equipment and fabrication procedures, wherever applicable for the equipment covered in this specification, shall also be in accordance with the latest applicable code requirements of the Indian Boiler Regulations.

4.06.00 The generator and accessories shall withstand, without damage, any rate of

acceleration/deceleration which the steam turbine may impart and any transient electrical conditions caused by sudden load reduction or electrical trip. The steam turbine and accessories shall be able to withstand, without damage, any transient thermal stresses, acceleration and deceleration to which they may be subjected within limitations set by proper function of the supervisory and protective devices, and within the limitations set forth in the Bidder's operation and maintenance manuals.

The turbine generator unit shall be capable of synchronising and running in parallel with utility Power Grid.

4.07.00 For quick restarting and flexibility during start-up of the Turbine-generator a

suitable HP-LP bypass system shall be provided. Bidder should specifically indicate the feature considered for bypass system and the minimum flow requirement to enable hot start-up of the machine.

4.08.00 The rotating components of the turbine-generator shall be statically and

dynamically balanced. The bidder shall indicate the maximum vibration level that can be tolerated on the bearing housings and shaft (and on bearing


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housing only for Exciter) during operation of the machines. 4.09.00 Noise Parameters The radiated sound level of the turbine-generator train shall not exceed 85 dB

(A) when measured at a distance of one (1) metre in plan or elevation from the outline of the turbine generator at the shaft centreline elevation at any load considering the background noise of the other machine and auxiliaries.

The radiated sound level of all auxiliaries supplied with the turbine generator

shall not exceed 85 dB (A) when measured at a distance of one (1) metre from the noise emanating surface. For valves & orifices, the measurement shall be made one (1) metre down stream of the devices and one (1) metre from the surface of the pipe for any combination of pressure drop and flow.

5.00.00 TURBINE TYPE AND RATING 5.01.00 The Turbine generator configuration shall be as per Manufacturer standards,

each complete with all related auxiliaries. The ranges of steam parameters and turbine generator output have been indicated in attached Annexure-I.

5.02.00 The turbine generator shall be guaranteed to operate satisfactorily on loss of

full export load without damage to the machine. 5.03.00 The steam shall be bled as un-controlled extractions from the high,

intermediate and low pressure stages for regenerative feed heating. Suitable arrangements shall be provided to prevent induction of water into turbine in accordance with Manufacturer's standard practice and the stipulations of ASME Standard No. ASME-TDP Part-I (Latest edition).

5.04.00 The turbine shall be capable of permitting a maximum sustained steam

pressure of at least 10% over the design turbine inlet steam pressure. The proposal shall indicate the maximum sustained steam pressure and maximum momentary pressure rise that can be tolerated and the aggregate duration of such swings beyond maximum sustained steam pressure.

5.05.00 The turbine generator set shall operate with part HP/LP Bypass under the

control of its speed governor to supply power for the unit auxiliary (house load operation) in case of sudden total export load throw off. The turbine shall not trip on overspeed due to the total load throw-off.

Turbine-generator set shall be capable to operate continuously at low load in

parallel with HP-LP bypass system under operation. 5.06.00 The proposal shall indicate the maximum inlet main steam temperature that

can be permitted together with the duration of each such incidence and the total duration thereof. This should satisfy the relevant stipulations of IEC-45.

5.07.00 The proposal shall indicate the maximum reheat steam temperature that can

be tolerated together with duration of each such incidence and the aggregate duration thereof.

5.08.00 Load change ramp may be 3% per minute during normal operation. The unit


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shall be designed to achieve following loading rates without unduly reducing component life:

From 30% to 50% rated : Shall not be more than 3% rated output output per minute for cold start only From 50% rated output : Shall not be more than 5% rated output to 100% TMCR per minute. 5.09.00 Maximum Temperature Variation S/H R/H a) Under Steady Condition : ± 5°C ± 5°C b) Load Changing rate of 3% rated output per minute : ± 10°C ± 15°C during 60% to 100% TMCR 6.00.00 TURBINE DESIGN & CONSTRUCTION 6.01.00 Casings 6.01.01 The casing shall be designed for hydrostatic test pressure of at least 50% in

excess of the maximum working pressure. The casings shall be free from sharp corners, sudden changes in section and other features which may result in unnecessary stress concentration. H.P. cylinder shall be double casing type.

6.01.02 Each turbine casing shall be provided with efficient draining facility. The parts

of the turbine casing which may come in contact with wet steam in normal operation or during start-up, shall be provided with an inter-stage drainage system whereby extracted water shall be prevented from re-entry to the blading and shall be transferred to either a convenient heater extraction branch or the condenser. The casing drains shall be provided with temperature sensing devices to ensure proper evacuation of drains.

6.01.03 Bolts, nuts and studs used for the turbine casing flanges and main turbine

valve bonnets etc., shall be with milled threads and of special alloy steel properly treated. Provision shall be made for electrical heating of the bolts to facilitate setting & loosening. In addition, the supplier shall indicate the design feature incorporated to prevent the seizure of nuts and studs and features, which will facilitate their easy removal after operating the machine. Bolts shall be designed to distribute the load evenly on all the threads without stress concentration. All the joints shall have sufficient flexibility to remain tight with rapid changes of temperature. Before shipment, each bolt shall be thoroughly examined and inspected to ensure freedom from any defects.

6.01.04 Necessary quantities of assorted bolt heaters, torque or other wrenches,

extensometers, bolt thread lubricator shall be included in the proposal as part of maintenance tools and tackle. The proposal shall specify bolt loading and strains and shall state the estimated period in which retightening or


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replacement of the bolts will be required and shall furnish detailed data, method and instruction for this purpose.

6.01.05 The spring supports of the turbine on the foundation shall be designed

considering the expansion and contraction of the machine during thermal cycling. Axial movements shall be allowed by anchoring at one point and central position shall be maintained by fitted keys.

6.01.06 The casing design shall permit inspection of all the bearings without

dismantling the casing. 6.01.07 All special insulation, paints, sprays along with equipment required to apply

these on steam turbine shall be included in the Bidder's scope of supply. 6.01.08 The steam extraction branches shall be located on the lower half casings and

shall be machined with weld end preparation except in the case of LP casing where bolted flanges will be acceptable.

6.02.00 Rotor 6.02.01 Prior to machining of the rotor made of forged alloy steel, adequate number of

test specimen shall be examined to ensure uniformity of material composition and strength. Large forgings shall be bored through, if required, along the axis in the centre, and examined for any flaws. The rotor shall be heat stabilized after machining. Ultrasonic, magnetic particle and other methods of test shall be applied to each rotor to ensure homogeneity of the materials and freedom from non-metallic inclusions, voids and cracks.

6.02.02 After the assembly of the blades, each complete rotor shall be balanced for

both static and dynamic conditions so that the assembled rotor will perform satisfactorily under all conditions of operation. The peak-to-peak measured value of vibrations shall be within 25 microns on the bearing housing and within 75 microns on shaft under steady state operating conditions. The critical speed/shall be in line with IEC 45.

6.03.00 Nozzles & Blading 6.03.01 All nozzles and blading shall be of hard, corrosion and erosion resisting alloy

steel suitable for the temperatures encountered. In the low pressure stages where the moisture percentage and the blade peripheral speeds are high, additional protection against erosion by way of hardened surface of blades or strips of erosion and corrosion resistant material such as stellite, secured to the leading edge, shall be provided. Suitable arrangement for the removal of moisture from at least the last LP stage shall be provided.

6.03.02 The method of fixing of the blades to the rotor needs to have been

satisfactorily proven by long use in operation. Care shall be taken to ensure that the natural frequency of the rotor blades is far away from the rotational frequency of the machine, which may vary from 47.5 Hz to 51.5 Hz.

6.03.03 LP Turbine shall have stand-alone type blades capable of sustaining -5% &

+3% grid frequency variation. 6.03.04 The last stage blade design and construction shall be of proven type with


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adequate care in selecting annular velocity. 6.04.00 Turbine Exhaust Casing 6.04.01 The turbine exhaust shall be designed for recovery of the leaving velocity and

reduction of exhaust loss. The turbine exhausts shall be suitable for connecting to the condensers either by welding or through expansion joints. The unit shall be provided with turbine exhaust hood spray system to protect the turbine against excessive temperature due to windage at no load and low load condition and during LP bypass operation. The system shall be provided complete with spray nozzles, an automatic spray water control valve and all inter-connecting piping between the nozzles and the spray water control valve, all necessary control, instruments and fittings.

The exhaust hood shall be equipped with pressure relief bursting diaphragms

(piercing type) designed to rupture at a specified internal pressure so as to limit the exhaust hood pressure within a safe margin. The diaphragms should be of sufficient area to pass the maximum L.P. exhaust steam plus flash steam entering the condenser.

6.05.00 Permissible Maximum Forces and Moments on External Connections 6.05.01 The bid shall indicate the values of maximum forces and moments that can

be accepted on the external connections of the turbine at main steam inlet, cold reheat outlet, hot reheat inlet, all extraction outlets and the low pressure exhaust to the condenser.

6.05.02 The thermal movements of the above-mentioned points with respect to a fixed

point shall also be furnished with the bid. These movements occur when the turbine is heated from cold to the full load operating conditions.

6.05.03 The contractor shall co-ordinate the allowable forces, moments and

movements with the piping design taking into considerations all operating conditions, transients like closing of ESV and bypass valve.

6.06.00 Bearings 6.06.01 The turbines shall be provided with an adequate number of

amply-proportioned bearings (preferably single point bearing support) to maintain proper alignment of the turbine, including generator & excitation system under all load conditions of operation. Bearing temperature shall be maintained within permissible limits by adequate supply of cooling oil. All main bearings shall be lined with tin base babbitt and the lining shall be properly secured to the bearing shell. To reduce maintenance difficulties, all bearings shall be accessible without having to remove cylinder covers, cross-over piping etc. Bearings shall be so split that the upper half is readily removable. The lower halves of the bearings shall be capable of being removed and replaced by minimum lifting of the shafts.

6.06.02 The rotor axial position shall be maintained by a thrust bearing assembly of

adequate capacity. The design of the thrust pads shall be such as to get adequate lubrication and to maintain the required film of oil at the contact surfaces at all times. Proper arrangement shall be made to maintain oil pressure under all load conditions of operation. The design shall incorporate


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arrangements for monitoring thrust bearing metal temperatures. Devices shall be provided for annunciation of an impending failure of the turbine thrust bearing. Additional switches shall be provided for alarm and trip of the unit in case of a thrust bearing failure.

6.06.03 The metal temperature of all bearing shells shall be monitored by

thermocouples with extension right into the white metal layer. Provision shall also be made to measure the temperature of the oil leaving the bearing. Bearing oil sight flow shall be provided.

6.07.00 Coupling The rotors shall be solidly coupled by means of integrally forged flanges, in

effect forming a single shaft system. Fitted bolts shall be provided to prevent slippage under abnormal operating conditions. They shall be of such design as to facilitate easy alignment during erection.

6.08.00 Seals 6.08.01 To minimise leakage of steam in between rotating and stationary parts of

turbine, renewable type seals shall be provided. Suitable shaft packings, which will effectively seal against steam leakage out of the turbine and/or air ingress into the turbine, shall be included. The labyrinths shall be of multi-section spring backed type, which would allow for any temporary deformations of the rotor shaft without overheating the rotor due to friction. Steam sealed units are preferable. The sealing steam shall be returned to the turbine cycle wherever possible.

6.08.02 A gland steam pressure regulation valve and desuperheater, if required for

automatic regulations, shall be included in the proposal. All necessary piping for steam seals and their drains, for satisfactory operation, shall be furnished. Arrangement for supply of suitable steam to seals, for hot restart of the unit, shall be incorporated in the design and furnished with bid. The seal steam parameters shall be so chosen as to facilitate easy supply of the same even under varying operating conditions.

6.08.03 A gland steam condenser, if required, shall be provided to condense all gland

leak-off steam and return the same to the cycle. The turbine glands shall be connected to gland steam condenser which shall be maintained at a slight vacuum to prevent leakage of steam from turbine to the atmosphere at the seals. The gland steam condenser shall be provided with suitable exhausters (A.C. motor driven) and necessary isolating and non-return valves. Exhausters shall be 2x100% capacity and the exhaust shall be led outside the building. A suitable by-pass of the gland steam condenser to the exhausters shall also be provided along with desuperheater.

6.09.00 Turning Gear 6.09.01 The turbine generator shall be equipped with hydraulic turning gear or electric

motor driven rotor turning gear capable of continuously rotating the turbine shaft to effect fast uniform cooling and warming during the coasting down and start up respectively.

6.09.02 The turning gear shall be designed to automatically disengage when the shaft


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speed increases and automatically engage when the speed comes down to a preset rpm. The turning gear system shall have all necessary instruments and controls for remote operation from turbine generator supervisory panel. In addition to the above, emergency provision for manual cranking of the turbine shaft shall be made. The lubricating oil shall be available to the bearings during manual barring operation. The turning gear operation shall be interlocked with the lubricating system to prevent the operation without bearing lubrication. The turning gear torque motor shall be provided with all other requisite interlocks and protection. Provision should be kept for disengaging and checking the turning gear motor while turbine is under operation (in case of electric motor driven turning gear).

6.10.00 Valves 6.10.01 Emergency Stop Valves The turbine shall be equipped with emergency stop valves, each operated by

hydraulic actuator and complete with hangers, supports, instruments and necessary piping up to turbine inlet. The stop valves should rapidly & completely cut-off the supply of the steam to the turbine after being triggered by monitors should a dangerous condition arise. The valves shall be designed for high speed closing and maximum reliability. The design of the pipes and valves shall be such that steam flow through them does not cause any objectionable noise or vibration. The system shall be fail-safe whereby loss of oil pressure at hydraulically operated mechanism shall result in valve closure. The valve chest and the hydraulic mechanism shall be easily accessible for inspection and maintenance. The valves shall specifically include the following features:

a) Devices to trip the generator and close all non-return and isolating

valves on the extraction lines, when these stop valves are closed. b) Mechanical position indicator to show valve open/close/travel and signal

switches to indicate valve position (open or close). These signal lamps shall be mounted on valve testing panels and shall also be duplicated on the turbine generator supervisory panel.

c) Arrangement for sequentially testing each stop valve to ensure freedom

of movement and its complete control and protective system while the unit is on load.

d) Local & remote manual/automatic tripping from turbine generator

supervisory panel. e) Coarse mesh permanent strainers for normal operation and extra fine

mesh temporary strainers for initial operation. f) The design of the stop valve shall allow blowing out of steam prior to

start-up. Necessary blow-out pipe connection with covers shall be furnished for this purpose.

g) The stop valve shall be located as close to the turbine as possible so as

to contain a minimum volume of entrapped steam, thereby limiting the turbine overspeed to a safe value.


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h) The valve shall be lagged with insulation and provided with attachments

for hangers/supports and also lifting eyebolts. i) The valve shall be designed to prevent excessive erosion by suitable

stelliting of various components. 6.10.02 Reheat Stop Valves and Interceptor Valves a) The turbine shall be provided with reheat steam stop valves and

interceptor valves or combined stop-cum-interceptor valves operated by hydraulic actuators and complete with hangers supports, instruments and necessary piping upto the turbine inlet.

b) The design of interceptor valves shall include all the features as

specified under cl.no.6.10.01 above so far as they are applicable. 6.10.03 Multiple Inlet Control Valves To maintain high efficiency over the entire load range, multiple inlet control

valves shall be used. The design shall be such as to ensure smooth flow and low-pressure drop across the valve. The valve design shall take care of the expansion of valve seats so as to prevent damage and consequent leakage of steam. The system shall be fail-safe whereby loss of oil pressure at hydraulically operated mechanism shall result in valve closure. The valve chest and the hydraulic mechanism shall be easily accessible for inspection and maintenance. The control valves shall be designed for both parallel and sequential mode of operation.

6.10.04 Non-return Valves a) Double valves shall be provided on all extraction lines except for

extraction line to LP Heater-1 in condenser neck. For extraction line to deaerator both the NRVS shall be power operated type.

b) One of these valves shall be hydraulic/pneumatic swing check/piston lift

type quick closing valves. These valves shall be operated by means of solenoid impulses. They shall be suitable for on load testing

individually. They shall also be fail-safe and automatic closure of valves shall take place under conditions of loss of auxiliary power, hydraulic/pneumatic pressure etc. These check valves shall close positively on turbine trip and at extremely high heater level. The non-return valves shall be located as close to the turbine as possible, so as to reduce quantity of entrapped steam.

c) Each CRH line one hydraulic/Pneumatic power operated Quick closing

non-return valve (QCNRV) shall be provided. Design of CRH line NRV shall include all relevant features as described above the extraction line NRVs.

d) The material of the valves shall be compatible with the material of the

piping on which the valve is mounted. However, the material shall not be inferior to the following :


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NRVs on CRH line and on extraction lines to HP heater : ASTM A 217 WC9 Other NRVs : ASTM A 217 WC6. 6.11.00 Vacuum Breaker To bring the turbine rotor from full rated speed to rest as quickly as possible

whenever required, necessary vacuum breaker with silencer, permitting the rapid reduction of vacuum in condenser, shall be included. Provision shall be made for remote operation of vacuum breakers. Vacuum breaker valve with pneumatic actuator shall be of gate type with provision of sealing.

6.12.00 Electro-Hydraulic Speed Control System Duplex type electro-hydraulic speed control system shall include the speed

governor, emergency governor, emergency trip, speed changer, load limit device, initial pressure regulator etc. The speed control shall act together with the turbine automatic run up system.

6.12.01 Speed Governor The primary sensing element may be electrical or suitable sensitive

mechanical element and shall be highly reliable and capable of incorporating automatic start feature.

The speed governing system shall limit the over speed of the turbo set below the trip points or safe limits on loss of full load, so as to avoid unit tripping by the emergency over-speed device. The control shall operate satisfactorily without causing or permitting the turbine to hunt or race under any conditions of steam supply and exhaust with steam being extracted for regenerative feed heating and under any conditions of variation in load regardless of whether the turbine set is operating isolated from other generating sources or in parallel with other generating sources. The speed-sensing element shall respond to small speed variations so as to keep the dead band within 0.02% of rated speed, at any power output. The steady state speed regulation and steady state incremental speed regulation shall be within satisfactory limits. The speed droop or speed regulation shall be adjustable within 2 to 8% rated speed. Necessary arrangement shall be there to avoid stickiness of control valve stem at any percentage opening when the governing system is in service.

6.12.02 Emergency Protection a) Emergency Overspeed Protection A quick acting emergency overspeed protection system (including

emergency governor) shall be provided to close instantly the emergency stop valves, control valves, reheat interceptor stop valves and also the non-return valves in the extraction lines at about 110% +_1% of the rated speed in case the speed governor fails to limit overspeed. It shall be capable of being reset when the speed is reduced to approximately normal, thus permitting the machine to be synchronised with other units. The emergency overspeed governor shall be provided with means for


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testing its operation even when the machine is on load, without exceeding rated speed of the unit. A back-up governing system shall be provided so that the emergency valve remains active during the test.

b) Turbine Trip Turbine trip should occur under the following conditions:- Overspeed, back-up overspeed, complete EHG failure, oil pressure very

low , condenser pressure high (loss of vacuum), thrust bearing wear, boiler tripped, shaft vibration high, AC generator tripped, all circulating water pumps tripped.

c) Emergency Stop Emergency stop should occur under the following condition:- Local manual emergency trip. Remote manual emergency trip. 6.12.03 Speed Changer The turbine shall be provided with a speed changer to control its speed or

power output within limits, locally and remotely operable from the turbine generator supervisory panel. The speed changer provided shall be capable of adjusting (manual/auto) the speed of the turbo set to any value in the range 95% to 105% of rated speed, to facilitate synchronising of the generator with the bus.

It shall be capable of varying the load on the machine from no load to full

load. Limit switches of resetting type, connected in the control circuit, shall be provided to prevent over travel. Speed changer D.C. motor shall be rated for continuous operation.

6.12.04 Load Limiting Device Turbine shall be equipped with a local/remotely operated load limiting device.

The motor for the remote control of the load limiting device shall operate on D.C. power supply. A remote position indicator shall be provided for indication of the setting of the load limit on the turbine generator supervisory panel.

6.12.05 Initial Pressure Regulator The turbine shall be provided with an initial pressure regulator to start closing

the steam control valves when the main steam pressure falls below a predetermined low value and the turbine shall be completely unloaded when the pressure falls to a further preset low point and it shall admit only sufficient steam to keep the machine running at full speed on house load. Provision shall be made to adjust or bypass this initial pressure regulator at start-up condition to facilitate starting with low steam pressure. Contacts shall be provided on the initial steam pressure regulating gear for signalling pressure unloading gear operation and pressure unloading gear reset.


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6.12.06 Supervisory Device Turbine Supervisory Instruments shall incorporate monitoring of the following

parameters as a minimum Turbine rotor eccentricity, casing expansion, Turbine rotor and cylinder differential expansion, vibration, steam and metal temperature of turbine, turbine speed as elaborated in Vol. - IIE.

6.13.00 Oil System 6.13.01 The turbine set shall be provided with complete self-contained oil systems.

The system shall supply oil for the lubrication of the turbine and generator bearings, for actuation of various components of governing and control system, hydraulic turning gear, seal oil etc. The control oil system may be separate from the lube oil system and provided with control fluid of fire resistant type if it is standard of the Manufacturer. The grade of oil to be used with complete specification for both control system and lube oil system shall be stated along with Bid. While developing the layout, Bidder should locate the oil tanks/coolers and route the piping in such a way that the installation becomes safe against possibility of any fire hazard and all efforts shall be given to improve layout during detail design also without any price implication to the Purchaser. Oil system of each unit shall include the following.

6.13.02 Oil Pumps

Lubrication Oil System

a) One (1) main oil pump driven from turbine shaft or Motor driven ( as per

standard and proven manufacturer practice) supplying oil, for bearing lubrication system when the turbine is running at normal speed.

b) One (1) booster pump or suitable oil injector to pressurise main oil pump

suction if applicable (as per standard and proven manufacturer practice).

c) Two (2x100%) full capacity A.C. motor driven auxiliary oil pumps for

fulfilling the same duty as main oil pump when starting or stopping the turbine and in emergencies. The motor shall be of the squirrel cage induction type. An adequately sized portable pump for line testing, common for both units shall be provided, control panels along with instrument as required and necessary shall be provided.

d) Provision for jacking oil pump(s) shall be made for the turbine-generator

set offered. One (1) A.C. motor driven and one (1) D.C. motor driven jacking oil pump shall be provided if jacking oil is required continuously while the machine is on turning gear. If the requirement is intermittent one (1) D.C. motor driven jacking oil pump shall be provided.

e) One (1) D.C. motor driven emergency oil pump with drive motor and

motor starter suitable for operation on D.C. voltage 220V with voltage variation from 190 V to 240 V D.C.

The D.C. motor shall be suitable for fixed resistance starting and

running conditions i.e. the capacity of motor shall be so selected that the


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starting resistance shall be continuously in the circuit without cutting out the resistance in running condition.

D.C. emergency oil pump shall supply lubricating oil requirement for all

bearings during emergency. D.C. oil system shall start automatically when lubricating oil pressure falls below a preset value even with auxiliary oil pumps in operation.

Turbine over head tank and the system shall be provided to take care of

turbine during coasting when there is blackout and DC E,O.P failure. Control Fluid System

a) 2 x 100% AC motor driven Control Fluid pumps mounted vertically in Fire resistant control fluid tank supplying oil, for control function [viz. servomotors/ actuators of control valves or for the operation of protective devices for TG set.

b) 2 x 100% AC motor driven circulation pumps to facilitate cleaning of the

Control fluid through Control Fluid Purification System. Seal oil System a) Two (1 x 100% AC & 1 x 100% DC motor driven) air side Seal oil pumps

for supplying seal oil from seal oil tank to the shaft seals through the air side seal oil coolers and filters. One emergency air side Seal oil pump driven by DC motor shall also be provided.

b) Two (1 x 100% AC & 1 x 100% DC motor driven) Hydrogen side Seal

oil pump for supplying seal oil from seal oil tank to the shaft seals through the Hydrogen side seal oil coolers and filters

All the pumps shall be provided with necessary strainers, valves and other

fittings. Pressure switches shall be provided for the automatic sequential starting of the motor driven oil pumps. A panel incorporating pressure switches, transmitters and testing push buttons shall be furnished for on-load testing of all interlocks. Such on-load testing shall be so arranged that safety of the system is not jeopardized at any time.

6.13.03 Oil Reservoir

The turbine set shall be provided with an oil reservoir of adequate capacity. The capacity of the tank shall be so chosen that the full quantity of oil circulating through the system is retained for a controlled time ensuring thereby proper sedimentation and air removal. The retention time should be indicated. The capacity of the oil tank shall also be adequate to contain the total volume of oil that can be drained from the circuit into the tank. It shall be provided with removable stainless steel basket strainers and at least two oil level indicators out of which one should be visible from turbine operating floor. High and low level alarm switches to be connected to the supervisory control panel annunciation system and overflow device shall be provided. A suitably located temperature switch (with duplicate contacts), for remote high temperature annunciation, indicating the possibility of fire inside the tank, shall be provided. Two independent connections shall be provided for the


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tank - one for draining and sampling and the other to facilitate connection to oil purification system. Necessary manholes with bolted covers, pipe connections with flanges etc., as required shall be provided. The proposal shall include necessary access ladders, platforms and railings. Two 100% capacity vapour extractors, driven by motors shall be furnished. The extracted vapour shall be led outside the turbine house building and provided with mist eliminator/oil separator at the terminating end of the vapour extractor line. The necessary supports, piping, accessories etc., shall also be furnished. The outer surfaces of all piping in the reservoir and the inner surface of the tank shall be coated with corrosion resistant paint.

6.13.04 Oil Coolers The oil system for the turbine set shall include adequate number (2 x 100%

capacity) of shell & tube type oil coolers with at least one standby cooler, each with sufficient cooling surface (15% excess tube surface) to cool the oil to a permissible limit at the inlet of the bearings when supplied with cooling water at maximum inlet temperature of 39°C under 5% tube plugged condition; and the system shall be designed accordingly. Device to detect tube leakage may be mentioned in the proposal along with the cooling water regulation requirement during low cooling water temperature etc. The coolers should be designed for DM water service and cooler tube material shall be Stainless Steel. Manually operated lockable type valves shall preferably be provided on the oil side of the coolers to facilitate change over from one oil cooler to the other without interfering with the unit operation. Suitable device for mechanical interlocking of valves shall be provided to ensure that any one of the two circuits is in operation at any time without any interruption to the cooling system. The oil coolers shall be provided with necessary thermometers for measurement of water and oil temperatures at inlet and outlet. Design of oil cooler, in general shall be as per the latest version of TEMA. The oil pressure in the cooler shall be greater than the water pressure under all operating conditions. Pressure gauges shall be provided at the inlet and outlet nozzles for oil and water. The tube bundles shall be suitable for removal for maintenance purpose.

All oil line drain valves shall be lockable type. 6.13.05 Oil Pipings & Fittings Complete inter-connecting oil piping to and from all pumps, coolers, bearings,

oil purification units and oil reservoir, shall be provided. All high pressure lines around the turbine and all pipes close to hot pipes and parts shall be preferably shielded in double piping so as to prevent oil from spraying on to hot turbine parts/piping due to high pressure oil leakage. Equivalent suitable arrangement for the prevention of fire-hazards due to leakage of oil shall be fully elaborated in the offer for the Owner's perusal. The oil return lines from bearings shall be provided with illuminated sight fittings. The drainpipes shall be properly sloped.

6.13.06 Filters and Strainers Filters shall be provided at immediately upstream of all bearings and

generator seals. All the pumps shall be equipped with suction strainers. All filters shall be duplex type comprising of stainless steel elements having


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mesh size as per proven practice of the manufacturers. Differential pressure switches with alarm shall be provided across the filters.

6.14.00 Stress Evaluator 6.14.01 Stress evaluator shall be provided for continuous on line monitoring of

thermal stress levels and safe operation of the machine. 6.15.00 High Pressure and Low Pressure Bypass Stations 6.15.01 Capacity a) The HP/LP Bypass System will operate as an integrated system. Both

HP & LP bypass system shall be electro-hydraulic type with latest version of Control valve, power cylinder and accessories. It should be latest state of the art international technology oriented.

The minimum leakage class of HP & LP bypass system shall be Class V

with full stroke operating time of the order of 3 sec.

b) The HP/LP Bypass may be required to operate in parallel with Turbine. However, under such parallel mode of operation, the combined steam flow through Turbine & HP Bypass will be limited to 60% BMCR flow.

c) The HP BP System shall be designed to handle 60% BMCR flow at

rated HP Turbine inlet steam conditions. d) The LP BP System shall be designed to handle 60% BMCR flow plus

the spray water flow, at low LP Bypass inlet pressure, which is start-up parameter.

6.15.02 Functions The HP/LP Bypass System is intended for use at following situations:

a) On hot starts to facilitate matching boiler steam to turbine metal temperatures prior to steam admission to the turbine thus achieving a faster start-up and reduced thermal stresses in the turbine.

b) During cold starts, for Boiler temperature control and condensate

conservation. c) On load rejection or turbine trips, the bypass system will handle

sufficient steam flow to avoid a boiler trip out, thus allowing rapid reloading when fault condition clears.

d) The HP Bypass valve shall serve as pressure relief valve in case of

transient main steam pressure excursion. The HP BP valve shall modulate to maintain HP turbine inlet pressure, if it goes at about 6 Kg/Sq.cm above normal operating pressure.

6.15.03 The H.P. bypass shall reduce the pressure and temperature of the live steam

to the conditions usually prevailing at the outlet of the H.P. casing. It shall be arranged to discharge into the cold reheat line, thus enabling the steam


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generator with the reheater remain operational without the turbine. The steam leaving the reheater shall be dumped by the L.P. bypass into the condenser.

6.15.04 The H.P. bypass station shall comprise of pressure reducing control valves

designed to control the upstream pressure and spray type desuperheater, using feed water through spray water control valves, to control the down-stream temperature. All valves offered shall be of positively closing type and shall facilitate easy maintenance in-situ.

A non-return valve on each of the cold reheat lines shall be provided by the

contractor to safeguard against the back-flow of steam into H.P. turbine while H.P. bypass is in operation.

6.15.05 The L.P. bypass station shall facilitate steam supply from reheater outlet

directly to the condenser bypassing the I.P. and L.P. stages of the turbine. The system shall comprise of pressure reducing control valve designed to control the upstream pressure and spray type de-superheater using condensate taken from the outlet of the condensate pumps through spray control valves, to control the downstream temperature. Necessary actuators for the above valves shall be included. Complete system for pressure and temperature control valves and all other fittings shall be supplied under this package.

6.15.06 Both the HP and LP bypass control valves shall be designed to take the full

temperature difference of the inlet and outlet under all conditions. 6.15.07 The control of the bypass stations shall be by essentially two control loops : a) Pressure control loop. b) Temperature control loop.

Signals for the pressure control of the bypass shall be taken from the upstream of it and the set points shall be adjustable. The facility for the remote manual adjustment of the set point shall be provided. Signals for the temperature control shall be taken from the bypass downstream side and set point shall be provided with facility for remote manual adjustment. The equipment shall be provided with automatic control loop. The facility for remote manual control should also exist in case the automatic control fails. The necessary indicators to enable remote manual operation shall also be furnished.

6.15.08 The control system shall include the necessary safety device for the protection of

condenser. The device shall prevent dumping of the steam into condenser if the water injection pressure is too low, if the pressure in the condenser is too high or if flow of bypass steam is too large. The system shall include under the scope of this contract all the equipment, hydraulic servomotors as applicable complete with oil units and accessories, control devices, position indicators, sensing elements, piping and all accessories and instrumentation to manual regimes of operation. The control equipment for both H.P. and L.P. system are to be housed in a central control cabinet completely wired up and tested in factory.

6.15.09 Valves shall be so selected that the noise level is below 85 dB(A) at a distance of

1.0 M.


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6.15.10 The control valve for entire HP - LP bypass system shall comprise of smart type

Digital positioner with 4-20 mA DC output to be connected to DCS input cards and shall have inbuilt RS-232 or equivalent interface port for parameter setting, adjustment, testing, diagnostic and calibration of control valves directly through LAPTOP PC/Hand calibrator. Licensed version of required software shall also be provided to facilitate above requirement. Other details regarding the valves shall be as per the specification indicated in Vol.II-E.

6.15.11 Oil readily available in Indian market shall be used in oil unit of bypass station. 6.16.00 Drive Motors

All drive motors shall be as per Specification for Electric Motor presented in Vol. II-F of this Specification.

6.17.00 Schedule of Materials

The bidder shall submit the schedule of materials used in turbine construction. The materials shall be as per manufacturers standard and proven in use in other operating units. An indicative schedule of materials is given below:

a) Casings

HP & IP Casing : Chrome-Moly-Vanadium steel as per approved DIN/BS/ASTM Standards.

LP Casing construction. : Mild Steel welded

b) Turbine rotor : Nickel-Chrome-Moly-Vanadium Steel as

per approved BS/DIN/ASTM Standards. c) Fixed/Moving Blades : Chrome-Mole-Vanadium Stainless Steel.


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7.00.00 GENERATOR AND AUXILIARY SYSTEM 7.01.00 Type The synchronous generator shall be totally enclosed, horizontal shaft, driven

by the steam turbine at 3000 rpm. The Generator shall be three phase, two pole, cylindrical rotor, wye

connected machine with phase and neutral terminals brought out for connection to isolated phase bus duct.

7.02.00 Rating The Generator shall have following rating : Rated output excluding : 660 MW excitation power Power Factor : 0.85 lagging Terminal Voltage : 21 KV (or as per manufacturer’s

standard) Frequency : 50 Hz. Short Circuit Ratio : not less than 0.48 Minimum Capacitive MVAR rating at zero M.W. : 280 MVAR Rated Hydrogen Pressure : 4 / 5 bar Inlet Cooling Water Temp. : 39°C (Max) Efficiency : >98% The Generator rating listed above shall be guaranteed on the basis of

continuous operation without exceeding the temperature limits at rated hydrogen pressure.

1. Voltage Variation +/-5% continuously at rated power factor. Reduced MVA operation at 110% of the rated voltage. (to be indicated by the Bidder)

2. Frequency Variation 47.5 HZ to 51.5 HZ 3. Combined voltage and 5 % frequency variation 4. Power factor variation 0.85(lag) to 0.95(lead) 5. Operation under As specified in IEC 60034-1


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unbalanced load 6. Operation under I22t where Negative sequence current I2 expressed in per unit of

rated unsymmetrical current for a duration of ‘t’ second such that the value of I2t shall short circuit comply to IEC 60034-1.

7. Voltage Wave form The telephone harmonic factor (T.H.F) shall be within the limit

specified in IEC60034-1. 8. Short Circuit Capable of withstanding of 3 phases short circuit at the

withstanding generator terminals when operating at rated MVA and power capacity factor with 5% over voltage for a period of not less than 3 sec.

9. Special operating Capable of withstanding the electrical, mechanical and thermal

conditions stresses developed during fast reclosing of high voltage line, transmission line switching , faults, out of step operation and out of phase synchronization etc.

10. Line charging Not less than 30% of its rated MVA at zero pf leading..

Capability(MVAR) 11. Generator Neutral Non-effectively earthed through a distribution transformer,

Earthing loaded with a resistor. The core design to permit the flow of earthfault of at least 15 amperes for one (1) second without any core damage.

12. Impulse level & Surge Impulse level as per IEC60034- Pt 15.

Protection Surge arrestor of suitable rating shall be provided for the surge protection of generator winding. The surge capacitors also to be included.

13. Capacity with hydrogen Capable of delivering at least two third of rated MVA.

Cooler Out of Service.

14. Harmonics Voltage and current harmonics not to exceed limits as per IEEE 519.

7.03.00 Ventilation and Cooling System The stator winding shall be cooled by demineralised water flowing inside the

hollow conductors of the winding bars. The rotor winding shall be directly cooled by hydrogen. The stator core shall be cooled by hydrogen flowing through radial/axial ventilating ducts. For cooling of hydrogen the heat exchangers located inside the generator frame shall be supplied with demineralised water.

7.04.00 Insulation and Temperature Limits The Generator stator and rotor windings inclusive of main and neutral leads,

shall be provided with class F insulation but rated for class B temperature rise.


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The maximum permissible temperatures of different parts of the generator shall be as specified in IEC 34-1, 34-3 as applicable.

7.05.00 System Operation The Turbine-generator will be connected to the utility network through star-

delta step-up transformer. The generator will be non-effectively earthed through a distribution transformer and secondary loading resistor.

The Generator shall be capable of operating alone or in parallel with existing

generators and/or utility power pool. 7.06.00 Voltage and Frequency Variation The Generator shall be capable of continuous safe operation at rated output

and power factor under any of the following conditions: a) Terminal voltage variation of +_ 5% of the rated value. b) Frequency variation within 47.5 to 51.5 Hz. c) Absolute sum of combined voltage and frequency variation of 5%. 7.07.00 3-Phase Short Circuit Withstand The Generator shall be capable of withstanding, without injury, a three phase

short circuit at the terminals for three (3) seconds when operating at the rated output and power factor, at 5% over voltage with fixed excitation.

7.08.00 Asymmetrical Short Circuit Withstand The Generator shall also be capable of withstanding, without injury, any other

short circuit at its terminals provided the integrated product of (I2)2 x t shall be equal to or more than ten (10), where "I2" is per unit negative sequence current and `t' is the duration of fault in seconds, and the maximum phase current is limited to a value which does not exceed the maximum phase current obtained from 3-phase fault.

Unbalanced Load The Generator shall be capable of continuous safe operation with a negative

sequence current equal to or greater than 8% of the rated current, provided none of the phase current exceeds the rated current.

7.09.00 Voltage Wave Form When tested on open circuit and at rated speed and voltage, the telephone

harmonic factor of the turbine-generator shall not exceed 1.5%.


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7.10.00 Overload Capability With balanced current, the short time thermal capability of the generator

armature shall permit operation at 150% of the rated armature current for at least 30 seconds, starting from stabilized temperature at rated load.

7.11.00 Capacity with One Gas Cooler Out of Service In the event of one gas cooler being out of service, the generator shall be

capable of carrying at least 75% of rated load continuously, without the permissible temperature of the machine being exceeded. Also Capable of delivering atleast two-third of the rated maximum continuous load with ten (10) percent of tubes in each cooler plugged without the permissible temperature of the machine being exceeded.

8.00.00 GENERATOR AND ACCESSORIES 8.01.00 Stator Housing The stator housing shall be of totally enclosed, gas tight construction, having

sufficient mechanical strength and rigidity to withstand internal hydrogen explosion without any damage or permanent deformation.

The housing shall have suitable provisions for handling, lifting and/or jacking.

Manholes with sealing arrangement shall be provided to facilitate inspection of terminals, internals etc.

All leads, including power, control and instrumentation shall be brought out of

the generator housing through gas tight seals. 8.02.00 Stator Core The stator core shall be fabricated out of best quality CRGO so that losses

are minimum. The core assembly and mounting arrangement shall be such that the

transmission of the forced vibration of the core to the housing and foundation is effectively restricted.

The core assembly shall have adequate ventilation ducts for cooling by

hydrogen. Magnetic screens shall be provided to reduce the end zone heating by leakage flux.

8.03.00 Stator Winding The stator winding shall consist of three phase, double layer, bar type lap

winding. The strands making up the stator bar shall be rebel transposed to minimise eddy current losses.

The windings and all connections inclusive of phase and neutral leads shall

be insulated for full voltage to ground.


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In order to reduce the corona in the slot and where the stator bar leaves the stator core, a surface treatment corona grading system shall be applied which shall be carried outside the slot area.

Firm seating of the stator bar in the slot shall be ensured by proper wedging

and fillers. Ripple springs shall be provided below the slot wedges to compensate for any future shrinkages and ensure permanent firm seating of the bars in the slot during operation. The overhangs shall be suitably braced and supported to withstand the forces during normal operation and sudden short circuit at generator terminals. Teflon hoses with necessary dielectric strength shall provide the connection between cooling water manifolds and the stator bars. Cooling water pipes, manifolds and fittings shall be of stainless-steel; further these shall be suitably insulated from the stator housing to facilitate checking of winding insulation resistance.

8.04.00 Terminal Connection All phase and neutral terminals shall be brought out from the bottom of the

generator (non-driving end) and located in a non-magnetic steel terminal box. Phase terminal bushings shall be spaced to permit connection to isolated phase bus duct to provide complete phase isolation directly upto the generator housing. Adequate spacing shall be provided between phase and neutral bushings to permit connections of the neutral enclosure.

The bushing shall be porcelain type and complete with silver plated terminal

connectors. 8.05.00 Rotor The rotor shall be forged in one piece from alloy steel to ensure required

mechanical strength and magnetic properties. The forging shall be subjected to elaborate ultrasonic and mechanical tests to

ensure freedom from any internal defect. Shall have adequate margin between critical speed and running speed to ensure smooth running. After assembly, the rotor shall be dynamically balanced and subject to 120%

of rated speed for 2 minutes. 8.06.00 Rotor Winding Rotor winding shall be made of silver bearing hollow copper conductors.

Winding insulation shall correspond to Class-F, i.e. epoxy glass, mica, nomex etc. with temperature rise limited to Class-B. Rotor temperature shall also be measured.

Rotor winding shall be secured in the slots by suitable slot wedges and fillers.

The overhung portion of rotor winding shall be held in position against centrifugal force by retaining rings.


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The retaining ring shall be machined from high strength, non-magnetic alloy steel forging. The retaining rings shall be floating type, shrunk on rotor body and prevented from axial movement by snap rings/locknuts.

Suitable damper winding shall be provided on the rotor to permit increased

asymmetrical electrical loading. 8.07.00 Bearing The generator shall be provided with end-shield mounted self-aligning journal

bearings. The bearings shall be of split construction and forced lubricated from turbine oil system. Oil baffles shall be provided to prevent leakage of oil along the shaft.

Provision shall be made for hydraulic jacking of the shaft, if needed during

start-up and turning gear operation. Each bearing shall be provided with a well for thermometer in the oil return line and an illuminated sight glass to observe bearing oil flow.

Bearings shall be insulated from stator frame and foundation plate to prevent

shaft current. Provision shall be made for bearing insulation measurement while the machine is in operation. Insulating material to be nonhygroscopic epoxy glass laminate.

8.08.00 Shaft Seals Shaft seals, preferably of floating ring type, shall be fitted to the end shields to

prevent hydrogen leakage from generator housing. To ensure effective sealing, seal oil pressure in the annular gap between the rotating shaft and seal ring shall be maintained at a higher level than the gas pressure in the generator casing.

The H2 side seal oil housing shall be provided with oil baffle rings to prevent

intrusion of seal oil into the generator along the rotor shaft. The shaft seals and oil piping shall be suitably insulated to prevent flow of shaft

current. 8.09.00 Fans/Compressors Hydrogen shall be circulated in the generator in closed circuit by the axial

fans/compressors located on rotor shaft at either end. The fans/compressors shall be locked against tangential or axial movement.

8.10.00 Slip Rings The slip rings, if required, shall be located in an accessible position. The slip

ring enclosure shall be provided with latched door, internal illumination and safety glass observation windows on each side.

The enclosure shall be natural air ventilated with intake filters to clean the

cooling air and discharge filters to prevent discharge of the dust from brushes to the turbine room.


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The slip rings shall be helically grooved, alloy steel rings, shrunk fit into the shaft but insulated from it. Provision shall be made for easy change of slip ring connection for uniform wear of slip ring.

Brushes shall be removable, replaceable and pressure adjusted without use

of special tools. The design shall be such that these works can be accomplished with the units in operation.

For monitoring the rotor winding insulation and shaft voltage a separate brush

suitably mounted shall be provided. 8.11.00 Temperature Measurements Embedded temperature detectors, resistance (RTD, 100 ohm platinum as per

DIN standard) or thermocouple of duplex type, shall be built into the machine for measurement of temperatures of various active parts, bearings and cooling medium etc. Simplex type thermocouple/RTD is acceptable with double the number. The minimum requirements are listed below:

Twelve (12) detectors, four per phase and uniformly distributed around the

stator, located between insulated coil sides in stator slots. Twelve (12) detectors for stator core of which six (6) shall be located in the

end zones. One (1) detector in gas stream entering and one (1) in gas stream leaving

each hydrogen cooler. One (1) detector in water inlet and one (1) in water outlet of each hydrogen

cooler. One (1) detector in the primary water inlet and three (3) detectors at the

primary water outlet of the stator winding. Two (2) detectors for each generator bearings, located in the lower bearing

sleeve. Two (2) detectors for slip ring inlet and outlet air temperature (in case of static

excitation system). Temperature detectors for seal oil, in case seal oil cooler is provided. All temperature detector leads shall be brought out to a terminal box suitably

located on the either side of the generator frame for easy access. The leads shall be suitably fastened to the frame to prevent movement and shielded against stray field.

In addition to the ETDs, temperature switches shall be provided as required

for alarm and interlocks. All the above temperature detectors shall be duplex type.


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8.12.00 Seal Oil System a) System Seal oil system supplies pressurised oil at shaft seals to prevent

leakage of Hydrogen from and ingress of air into generator housing. Seal oil pressure shall be maintained automatically at higher level than

the H2 pressure in the generator housing over the entire operating range. The design shall be such as to reduce H2 - diffusion loss through seal oil to a minimum and maintain high H2 - purity level inside the generator casing.

b) Components The system comprises of oil tanks, defoaming chambers, vapour

extractors, pumps, coolers (if required by bidder), filters, interconnecting pipes, fittings, valves, gauges, thermometers. A Control and monitoring panel complete with annunciation shall be furnished. Damper tank for supply of oil to seal oil system under emergency condition, may be considered, if required by bidder.

c) Main Features The seal oil stream shall have Two (1 x 100% AC & 1 x 100% DC

motor driven) pump - one running and other standby for automatic cutting in on loss of seal oil pressure. Upon failure of both pumps, the seal oil supply shall be maintained by a 100% emergency seal oil pump (D.C. motor driven) without any interruption. There shall be individual starting/control panels for each pump and one common signalling panel. The A.C. seal oil pump shall also be connected with D.G. set to cater emergency.

Seal oil coolers (if required by the bidder) and filters shall be of 2 x

100% capacity designed for 36°C cooling water (DM quality) temperature. The piping and valve arrangement shall permit taking out any cooler/filter without affecting operation of the system.

Seal oil system shall have connection to turbine main oil system for

make-up and also for excess return. The turbine main oil system shall also serve as a back-up to seal oil system. The H2 side oil drain shall be suitably degassed before being returned to main oil system.

The Seal Oil system shall preferably be supplied through two separate

and independent streams - one for air side and the other for H2 - side the arrangement shall be rich that even in case of failure of H2 - side stream, sealing shall be maintained by the air-side stream.

8.13.00 Gas System The gas system comprises a hydrogen gas circuit, for cooling the stator core

and rotor windings, a carbon-di-oxide scavenging system and compressed air supply.


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The system is required to fill the generator with hydrogen, maintain it under

pressure, monitor and control gas purity, and to empty the generator of hydrogen.

The design is such as to ensure safe filling/emptying by preventing formation

of explosive H2 - air mixture. For filling, air is first displaced by CO2, which in turn is replaced by H2. While emptying, H2 is first displaced by CO2 before admission of air in the machine.

The major system components are H2 and CO2 gas manifolds, H2 gas

coolers, side stream H2 drying equipment, inter-connecting pipings, fittings, valves, gauges and other instruments, control monitoring panel complete with annunciation. Hydrogen shall be circulated in the generator in closed circuit by fans fitted on the rotor shaft at either end. H2 gas is cooled by DM water heat exchangers located in the generator housing. The cooler shall be of sectionalised design such that with one cooler section out of service, the unit can carry at least two-thirds rated load continuously, without exceeding the permissible temperature limits. Hydrogen coolers shall be so designed that it is possible to meet the full load requirement of the machine with at least ten (10) percent of the tubes in each cooler plugged. Cooler to be designed for atleast 10kg/cm2 gauge pressure on the gas side irrespective of lower normal operating casing pressure.

Two (2) full capacity refrigeration type H2 - drier with in-situ reactivation facility shall be provided. The arrangement shall be such that one drier can be taken out of service for reactivation without affecting the system performance in any way. H2 Storage and handling Unit shall be located as per the rules of Indian Explosives. Pressure measurement for cooling water inlet and outlet of hydrogen gas cooler and stator water inlet and outlet of stator winding to be provided.

The valves in gas system shall be of special design to minimise gas leakage. Safety relief valves shall be furnished both on low and high-pressure sides of the gas system. A manually operated vent valve shall be provided for discharging casing hydrogen to atmosphere in case of emergency to a location outside the building top.

During the transportation, storage and also during long shut down the

machine shall be kept under nitrogen atmosphere. Bidder shall bring out the requirement, if any, of Nitrogen gas. The complete nitrogen system along with the necessary nitrogen cylinders shall be furnished for each machine.

8.14.00 Stator water Cooling System i) System The stator cooling system comprises the closed loop, demineralised

(primary) water circuit for direct cooling of stator windings, the leads and the terminal bushings. Primary demineralised water shall be cooled in the stator coolant heat exchanger by means of secondary demineralised water, which is a part of the plant auxiliary cooling water system. One (1) mixed bed demineraliser (MBD) of adequate capacity to maintain the required quality of water. MBD to remain continuously


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in service in order to retain higher purity of stator cooling water with its associated electrical resistivity. The continuous online monitoring of stator water quality instruments to be provided. Terminal points of such system are described elsewhere in the specification.

The design for primary water circuit shall be such as to ensure a

continuous flow of primary water at constant winding inlet temperature, while maintaining the water quality to the desired level of purity. The maximum water pressure in the stator conductors shall be automatically maintained below the minimum hydrogen pressure over the entire operating range. Provision to remove entrapped air/gas in the stator winding/stator water system and provision to check hydrogen leakage through winding and system shall be made. There shall be individual starting panels for each pump and one common signalling panel.

ii) Components The system essentially comprises primary water storage tank, cooling

water pumps, water/water heat exchangers and filter units, one polisher unit with redundancy, interconnecting piping, fittings, valves, gauges, conductivity cells and regulating equipment. A stator cooling water control cabinet shall be furnished complete with control devices for operating and monitoring the system, runback and protective circuitry and annunciators.

iii) Main Features The storage tank shall have liquid level indication and shall be

supervised by a float switch, which actuate alarm if the level varies above or below normal.

The pumps, heat exchangers and the filters shall have 100% standby.

The standby pump shall be switched on automatically. The separate local control panel for stator water and seal oil system is

not envisaged. The required interlock and logic shall be implemented in DDCS.

The piping and valve arrangement shall be such that any pump/ cooler/

filter can be taken out of service for maintenance, without affecting the full generator output.

All metallic material used in the conductor cooling system that come in

contact with the water shall be stainless steel, copper-nickle, brass or similar materials to provide a system resistance to corrosion and which will have no effect on the cooling water resistivity.

The packing for joining the pipes flanges shall be teflon/neoprene type.

All the fittings of teflon hoses and manifold should ensure leakproof joints.

8.15.00 Generator Excitation System


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8.15.01 Type The excitation system shall be brushless excitation system/Static excitation to

meet the performance requirements specified hereinafter. 8.15.02 Performance Requirement

When the generator is subjected to sudden loss of rated output at rated power factor the system shall be capable of restoring the voltage within 2% of nominal preset value within negligible time.

a) The excitation system shall have sufficient reserve and redundancy to

permit effective utilisation of generator capability over the entire operating range and under all service conditions without any restriction. The excitation system shall have 2 x 100% channels including independent AVRs power converters and controls. The controls shall have two independent controllers, one for each channel with hot standby facility. Each shall be equipped for auto operation with the facility for selecting either channel in auto or manual mode.

b) The system shall function without hunting and shall be capable of

preventing any abnormal change or oscillation in the generator voltage.

c) The system shall have high initial response to improve steady state

and dynamic stability of the generator. d) The excitation system shall be capable of maintaining generator

voltage within+_ 0.5% of the preset value over the entire load range of the machine.

e) The reference voltage set point shall be adjustable over a range of 85

to 110% of the nominal rated voltage under all load conditions. f) The rated current and voltage of the excitation system shall be 110%

of the machine excitation requirements at rated output. The ceiling voltage shall not be less than 150% of the machine excitation voltage. Short time duty shall be on MCR base as per clause 1.14 of part III in VDE 530.

g) The system shall be capable of supplying the field-forcing requirement

for at least 30 seconds. The nominal excitor response ratio shall not be less than 3 per second.

The excitation system respond time shall be less than 0.5 sec (as per IEEE421 A). The excitation response ratio shall be more than 2.

8.15.03 System Components Brushless Excitation System The system shall comprise of the following major components :


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Permanent magnet pilot excitor (PMG) Digital Automatic voltage regulator (AVR) Brushless main exciter Metering and supervision equipment Cables between machine mounted equipment and excitation panels 8.15.04 Component Features Field Suppression System This comprises of essentially a two-pole field breaker and non-linear field

discharge resistor. The field breaker shall have two (2) trip coils. A crow bar comprising of two anti-parallel thyristor groups shall be included as additional over voltage protection.

Brushless Exciter The pilot exciter shall be 3-phase, revolving field type with permanent magnet

poles. The main exciter shall be 3-phase-revolving armature, forced air-cooled,

totally enclosed machine complete with its own water/air heat exchangers. The winding insulation shall be class-F or better. Embedded temperature detectors shall be provided for the air temperatures in

and out of each cooler and also for exciter bearing. Rectifier Assembly Mounted on Shaft In brushless excitation system when necessary rectifier bridge and other

assembly are mounted on Generator Shaft, arrangement shall be made for detection of fault with alarm in case of failure of any component.

Arrangement made for such detection shall be furnished in details for Owner's

perusal. Sufficient parallel diodes shall be furnished to allow for failure (including open

circuit condition) of 20% without any derating of exciter. The rectifier assembly shall be housed in a separate enclosure, complete with

observation windows and forced air-cooling arrangement. 8.15.05 Automatic Voltage Regulator The automatic voltage regulator shall be of high speed, continuous acting

solid-state design. The regulator shall be responsive to average of 3-phase voltages. The regulator shall be dual auto channel and manual channel type


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with a follow up circuit to ensure smooth transition from one mode of operation to the other.

a) Voltage regulator The excitation system shall be designed in such

a manner that due to any fault in AVR firing circuit pulse transformer, rectifying elements in any channel etc. excitation system shall be available with its full capacity. All rectifying elements shall have over voltage and short circuit protection

b) Number of channels Two numbers fully equipped automatic

channels having independent inputs and automatic changeover shall be provided. Either channel shall be capable of being the main or standby. Either channel shall be capable of being selected as manual also.

c) Characteristics - Auto control range (±)10% of rated terminal voltage in all modes for

voltage level adjustments of generator operation.

- Frequency range of 47.5Hz to 51.5Hz Operation

. - Accuracy at which Better than 0.5% of the set value over the generator voltage to whole load range of the generator

be held

- Range of transformer 0 to 15% drop compensation - Maximum change in <0.5% (when AVR is transferred from auto generator voltage to manual under all conditions of . . excitation) - Manual control range 70% of no load to 110% full load excitation d) Technical features The AVR shall be provided with minimum

following features :

- Channel reference Solid state microprocessor control Control - Ramp generation To enable gradual rise of reference signal

Circuit applied to the comparator circuit to avoid . . .. sudden voltage build up

- Transformer drop Suitable feedback proportional to compensation transformer drop to be provided for compensation


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- Limiters Limiters but not limited to following to be

provided: - Over excitation limiters - Under excitation limiter - Rotor angle limiter - Stator current limiter - Rotor Current limiter - Voltage/ frequency (V/F) limiter

- Power system stabilizer (PSS) The excitation system shall be provided with

power system stabilizer for achieving the dynamic stability of the system under most stringent conditions of operation in the phase of disturbance created by short circuits conditions, load rejections, switching on/ off of transmission lines. The power system stabilizer should have adoptable settings, which should automatically adjust to system reactance. In other words the system should provide automatic and continuous measurement of system reactance and power system stabilizer setting must continually adjust itself for any changes in the system reactance so as to provide required dynamic stability margins.

The following features/functions shall be incorporated in the regulator : a) Cross current (IR) compensation b) Slip stabilization c) Load angle limiter d) Volt/Hz. ratio controller e) Rotor temperature transducer/transmitter with remote mounted

indicating recorder f) Field current and voltage measuring equipment 8.15.06 Excitation Cubicles Self-supporting, sheet metal enclosure with swing doors and ventilating

louvers with wire gauge shall be furnished for the excitation and voltage regulating equipment. Provisions shall be made for cable entry from top and bottom. Forced ventilation system by means of fans shall be provided for the


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excitation cubicles. Failure of each fan shall be annunciated on the panel and UCB. The bidder shall indicate detail of cooling system envisaged.

8.15.07 Interconnections All interconnecting cables shall be furnished in required lengths for field

connections. 8.15.08 Remote Mounting Equipment Any devices and instruments other than control switches, push buttons,

indicating lamps, voltmeter and ammeters required for operation and control of the excitation system from unit control board shall be supplied loose by the bidder. A list of such items shall be furnished along with the offer. (Also refer Volume IIF/2 Section V for controlling of Generators, Turbine Governors including Generator auxiliary system)

8.15.09 Other Requirements The Bidder shall furnish in his offer, the VA burden accuracy class type of

connection etc. of CT's and VT's required to feed the AVR from the generator terminals.

The Bidder shall also furnish in his offer the details regarding technique and

time period for rapid defluxing of the machine in case of any internal or external fault.

In addition the excitation system shall include the following control and

protective features : a) Generator and exciter field ground detectors with a time delay to

prevent false ground indication during transients. Necessary slip ring/shaft brush shall be provided for this purpose.

b) Generator field over voltage protection to trip the generator. c) Alarm for inoperative condition of each diode/thyristor cells. d) The power system stabilizer is conjunction with the excitation system

shall be adjustable to provide damping torque to the machine system and tie line oscillation in the range of 0.1 to 3 Hz. Equipment required for the generation of the control signal to the stabilizer shall be furnished as part of stabilizer.

e) The power system stabilizer parameters shall be coordinated with the

parameters of the turbine-generator and the excitation system such that the loading capability of the generator can be fully utilised.

f) There shall be provision for changing polarity of rotor magnetic field. 9.00.00 INSTRUMENTATION & CONTROL Refer Volume : IIE for details of instrumentation & control requirements.


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10.00.00 TESTING AND INSPECTION The following tests shall be conducted on turbine generators : 10.01.00 Tests on Turbine 10.01.01 In addition to the tests mentioned in the lead specification the following shop

tests shall be conducted as applicable on the various components such as rotor, casings, blades, diaphragms, valves, pipes, flanges, bolts, etc. All such tests shall be documented and forwarded to Purchaser :

a) Boro-scope test b) Radiography / Ultrasonic/Magnetic particle test for crack detection c) Heat stability test d) Resonant vibration tests. e) Examination of threading tolerances etc.

f) Chemical Composition and quality tests on blades (moving). g) NDT in foundry.

h) Dimension & Visual checks.

i) Functional checks.

j) Ultrasonic checks after heat treat.

10.01.02 After the assembly of the various components of the turbine the following

tests shall be conducted : a) Verification of fits and operating clearances. b) Balancing test. c) Over speed testing of rotor guided by stipulations of IEC-45-1.

d) Tests for checking the proper operation of governors, control valves and auxiliaries.

e) Hydrostatic pressure and tightness testing of system (including fittings/

components). 10.02.00 Generator Tests 10.02.01 General The tests listed below shall be carried out on each and every generator to be

supplied against this specification. If possible, running trials shall be conducted for the generator, exciter and automatic voltage regulator


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equipment combined as a unit, on the test bed, and the Bidder shall clearly indicate in his bid whether he is able to meet these requirements.

The readings taken during the electrical tests, the results noted, and the

calculations made are to be included in a test report which shall include, inter-alia description of test method, equipment used and any limitations of the test plant.

10.02.02 Shop Tests a) Routine electrical tests on each generator i) Measurement of insulation resistance of the following before

high voltage test :

Terminal Bushings.

• Stator windings, including tan delta measurement.

• Rotor windings.

• Embedded resistance thermometers.

• Exciter side bearings and oil pipe connections. ii) Measurement of the DC resistance of the following when all

water units are running and one cooler unit is out of service:

• Stator Winding.

• Rotor Winding.

• Embedded Resistance thermometers. iii) Determination of generator open circuit characteristics. iv) Stator Phase Sequence Checking. v) Measurement of mechanical losses. vi) Determination of short circuit characteristics. vii) Measurement of core losses at the rated voltage and

frequency. viii) Determination of direct axis synchronous reactance & SCR. ix) Determination of potier reactance. x) Equivalent heat runs to determine temperature rises

comprising of an open circuit run at 110% of the rated stator voltage followed by a short circuit run at the rated stator current. A zero excitation heat run may be conducted at the


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BIDDER's option but in the absence of such a test no correction for the inclusion of zero excitation losses in both the open circuit and short circuit heat runs will be allowed in the calculation of temperature rises of the stator and rotor windings.

xi) Determination of generator efficiency by the separation of

losses at 100%, 80% and 60% load. xii) AC high voltage test of stator winding and stator terminal

bushings after heat run test.

xiii) Measurement of rotor winding impedance. xiv) AC high voltage testing of the field windings after the heat run

test, with the rotor revolving at 3000 rpm and also with the stationary rotor.

xv) High voltage testing of resistance temperature detectors after

the heat run test. xvi) Measurement of the insulation resistance of the items listed

under (i) above after the high voltage test. xvii) Calculation of the temperature rise of the stator and the rotor. xviii) Retardation test. xix) Measurement of phase to neutral and phase to phase

capacitance of all the three phases of the stator and the rotor and calculation of the equivalent generator capacitance as viewed from the generator terminals; also the measurement of the capacitance between the complete winding and the body and the dissipation factor.

xx) Hydrogen leakage test. xxi) Partial discharge test.

xxii) Measurement of –ve phase sequence impedence.

xxiii) Measurement of zero sequence reactance.

xxiv) Residual voltage measurement.

xxv) Phase sequence.

xxvi) Shaft voltage

xxvii) Vibrations

b) Type test on one generator


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i) Sudden 3-phase short circuit withstand test at 50% of the rated voltage and measurement of all reactances and time constants, SCR and synchronous reactance.

ii) A single-phase short circuit test at reduced excitation to

determine the zero and negative phase sequence reactances. iii) Telephone influence factor and harmonic analysis of the

voltage waveform. iv) Impulse withstand voltage test on the terminal bushings. c) Mechanical Tests on Each Generator i) Mechanical inspection. ii) Measurement of bearing vibrations. iii) Overspeed test. iv) Hydraulic test on coolers. v) Hydraulic tests on machine housings. vi) Rotor balance. d) Air leakage test on hydrogen cooled stator frame. e) Resistance temperature detector test. f) Flow continuity for armature winding.

g) Additional Tests :

• Gas tightness after test bed assembly • Mechanical loss and core loss test. • Measurement of cold resistance of the stator, rotor winding

and RTD. • Measurement of insulation resistance of the stator including

bushings and rotor windings, embedded resistance thermometer, bearings, shaft seals.

• Measurement of polarization index of stator winding. • Measurement of bearing vibration level during running with and

without excitation and also during short circuit test.

h) Excitation System, Regulator Equipment etc.

• Inspection at intermediate assembly stage • Wiring and bus bar check, including checks on printed circuits.


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• Examination of thyristor characteristics for forward voltage drop, firing characteristic, reverse voltage withstand capacity etc.

• Characteristic check on amplifiers and associated circuitry • Simulated tests on excitation and AVR circuits to demonstrate

control, response, discrimination and excitation limit features. • Function and HV test on field breakers. • High Voltage and insulation tests. • Visual, dimensional and appearance check on various panels

and equipments

10.02.03 Field Test on Each Generator The field tests to be conducted at site shall include but not be limited to those

listed below. Any other test considered necessary by the VENDOR shall also be carried out by him.

a) Electrical i) Measurement of the insulation resistance of the stator and

rotor windings to the frame and between phases, after drying out the machine, and measurement of the polarisation index.

ii) Measurement of the DC resistance of all windings and

embedded temperature detectors. iii) Measurement of the insulation resistance of bearings. iv) Capacitance measurement and dissipation factor between the

winding and body. v) Open circuit and short circuit tests. vi) Measurement of temperature rise at the rated load. vii) Performance capability of the machine. viii) Line charging capacity. ix) Short circuit tests on the generator HV end and the generator

transformer HV end to check the stability and operation of the generator and the overall (i.e. generator and generator transformer) differential protections and negative phase sequence protection.

b) Mechanical i) Hydrogen leakage test. ii) Vibration test. iii) Overspeed test.


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iv) Hydraulic tests on coolers. v) Bearing and shaft current test. c) Load throw-off tests. 10.02.04 Electrical Tests on AVR The tests to be conducted, at works, on the Digital AVR shall include, but not

be limited, to those listed herein. Any other tests recommended by the VENDOR shall be specifically brought out in the tender.

a) Accuracy test. b) Sensitivity test. c) Response ratio test. d) High voltage test. e) Performance test at reduced supply voltage. f) Performance test of all limiters. g) Impulse input response test. h) Manual channel following auto channel test. i) Range of voltage adjustment test for both auto and manual channels. j) Output test. k) IR test. Site tests on Digital AVR. 1. Logic sequence check. 2. Functional test - Signal flow test - i) Actual value setting ii) Checking and setting of gate control circuit iii) Regulator and limiter setting iv) Light load characteristic v) Current sharing vi) Heat run test


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3. Alarm circuit check. Tests listed from 10.02.04 (a) to 10.02.04 (k) above shall be carried out at site. 10.02.05 Electrical Tests on Excitation Equipment All components of the excitation system shall be tested in accordance with

the relevant standards and type and routine test certificates shall be furnished.

The VENDOR shall furnish test reports, performance curves, drawings and

data as listed. 10.02.06 Excitation system, Regulator Equipment etc.

a. Inspection at intermediate assembly stage.

b. Wiring and bus bar check, including checks on printed circuts.

c. Examination of thyristor characteristics for forward voltage drop, firing characteristic, reverse voltage withstand capacity etc.

d. Characteristics check on amplifiers and associated circuitry

e. Simulated tests on excitation and AVR circuits to demonstrate control,

response, discrimination and excitation limit features.

f. Function and HV test on field breakers.

g. High voltage and insulation tests

h. Visual, dimensional and appearance check on various panels and equipment.

The tests indicated above are minimum requirements, however, during QAP finalization the detailed Inspection and Test plans shall be submitted by successful bidder for approval of purchaser.

11.00.00 DATA, DRAWINGS & INFORMATION REQUIRED 11.01.00 To be Submitted at the Time of Proposal 11.01.01 List of auxiliary equipment, accessories and tools, furnished including name

of manufacturer, size, range etc. 11.01.02 Heat Rate calculation corresponding to 100%, 80%, 60%, 50% and 40%

turbine loads for modified sliding pressure operation and condenser vacuum of 77 mm HgA with zero percent makeup.


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11.01.03 Turbine cycle heat balance diagrams for various loads corresponding to rated upstream steam pressure and temperature and each of the following condenser operating conditions shall be furnished :-

i) 0% make-up and 77 mm HgA Vacuum. ii) 0% make-up and 89 mm HgA Vacuum. iii) 1% make-up and 77 mm HgA Vacuum. iv) 1% make-up and 89 mm HgA Vacuum. v) 3% make-up and 77 mm HgA Vacuum. vi) 3% make-up and 89 mm HgA Vacuum. The following load condition heat balances shall be given as minimum :- a) 100% load ; b) 80% load ; c) VWO condition ; d) 60% load ; e) 50%

load; f) 40% load g) Top H.P. heater out of operation ; h) All H.P. heaters out of operation ; i) HP and LP bypass conditions under house load operation.

11.01.04 The bidder shall also furnish heat balance diagrams for modified sliding

pressure operation corresponding to condenser parameters (as in Cl. no. 11.01.03 (i) to (iv) above) and at following loads :

a) 100% load ; b) 90% load ; c) 80% load; d) 60% load; e) 40% load. 11.01.05 Turbine Performance Curve and Characteristics at all conditions mentioned in

Clause No. 11.01.02 as indicated below : a) Turbine expansion curves b) Expansion Line End Point (ELEP) and Used Energy End Point

(UEEP) for condenser exhaust pressures of 63.5 mm, 70 mm, 77 mm and 89 mm of Hg. absolute.

c) Extraction stage pressure versus flow to next stage. d) i) Exhaust loss versus condenser steam flow and the last stage

annular steam velocity annular area of the last stage and necessary information regarding correction.

ii) Exhaust loss versus annular velocity. e) Throttle flow vs. gland leakages with leakage enthalpies. f) Heat Rate Correction Factors i) Percent change in heat rate versus initial throttle temperature.


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ii) Percent change in heat rate versus initial throttle pressure. iii) Percent change in KW load versus initial throttle pressure. iv) Percent change in KW load versus initial throttle temperature. v) Percent change in heat rate vs. exhaust pressure (family of

curves). vi) Percent change in KW load vs. exhaust pressure.

vii) Reheat pressure drop & temperature correction curves - showing - % change in KW and heat rate.

viii) Reheat spray and Superheat spray vs. change in KW and heat

rate. g) Turbine Start-up Curves. 11.01.06 Allowable forces, moments and thermal movements on all equipment/

terminal points. 11.01.07 Generator loss, fixed and variable as well as mechanical losses for various

outputs. 11.01.08 Generator Curves and Characteristics a) Characteristics b) "V" curves c) Generator capability curve for different hydrogen pressure d) Reactive capability curves e) Generator transient and sub-transient reactances f) C.T. characteristic curves g) Communication non-interferences test curve h) Generator losses fixed and variable i) All other necessary curves data for the generator, Excitor and its

auxiliaries. j) Overload characteristic. k) Unbalanced load characteristic. l) Salient technical data.

m) Reactance


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n) Guaranteed loses 11.02.00 After Award of Contract 11.02.01 Final versions of all the documents, furnished under 11.01.00. 11.02.02 Foundation drawings and loading data (dead load & operating loads - static

and dynamic, including generator short circuit load, rotating mass etc.). 11.02.03 Criteria/calculations for sizing and selection of major equipment showing

compliance with specifications and codes. 11.02.04 Drawings, Data And Manual For Excitation System

The following documents shall be submitted by the Contractor for Purchaser’s approval. • Completely filled in technical Schedules • Description on Excitation System & AVR • Excitation curves • Catalogues • General arrangement and sectional drawings of Excitation system • Schematic diagram of excitation system • List of tests and detailed test procedures for excitation system • General arrangement and sectional drawings for all panels / cabinets,

cable entry details and Bill of Materials • Interconnection diagram • Layout drawings indicating the location junction boxes, push button

stations, transmitter racks, etc. • Quality Plan • Test certificates • Erection & Commissioning Manual • Operation & Maintenance Manual

11.02.05 Quality Assurance Plan.


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SPECIFIC DESIGN CRITERIA FOR

TURBINE GENERATOR SET

SL. NO. I T E M CRITERIA REMARKS

1.

2.

Type of Turbine Critical Parameters

The Turbine generator configuration shall be as per Manufacturer standards, each complete with all related auxiliaries a) Continuous rated output at generator terminal (excluding

excitation power) at 0.85 pf lagging under normal regenerative feed heating under following conditions – 660 MW

b) Cooling Water Temperature For Condenser For Other Coolers i) Design - 33°C 36°C ii) Maximum - 36°C 39°C iii) Minimum - 17°C 20°C

i) For condenser cooling, Sea water from cooling tower shall be used. ii) All other coolers under TG cycle shall be connected with a closed cycle DM water system as detailed under Volume II-H.



DCPL-11Z02

SL.NO. I T E M CRITERIA REMARKS

c) Condenser exhaust pressure i) Design : 77mm Hg abs. ii) Maximum : 89 mm Hg abs. d) Throttle Steam Pressure before Turbine stop valve : 247 Kg/Cm2 abs.(minimum) e) Throttle Steam Temperature before Turbine stop : 565°C f) Reheat Steam pressure at IP turbine inlet : As optimized by the Bidder g) Reheat Steam Temperature at IP Turbine inlet : 593°C h) Speed : 3000 rpm. i) Frequency variation : 47.5 Hz to 51.5 Hz [for

continuous operation] Grid frequency - 50 Hz j) Design DM-water make- up to thermal cycle : 3% of throttle steam flow.

(maximum)



DCPL-11Z02


3.

4.

5.

Generator Type Generator parameters Generator Class of Insulation

a) 2 pole, 3 phase cylindrical rotor. b) Hydrogen Cooled rotor and stator core. Water cooled stator

winding. a) Rating – 660 MW continuous at 0.85 pf lagging. The

maximum permissible temperatures of different parts of the generator shall be as per IEC 34-1, 34-3 as applicable.

b) Terminal voltage 21 kV (or as per manufacturer’s standard)

c) Frequency 50 Hz d) Minimum Capacitive MVAR rating at zero MW : 280 MVAR e) Short Circuit Ratio : not less than 0.48 Class F but limited to class B temperature rise

6. Voltage & Frequency variation for continuous output

a) ± 5% of the rated value for terminal voltage variation b) - 5% to +3% of the rated value for frequency variation c) Absolute sum of combined voltage and frequency variation

5%



DCPL-11Z02


7.

Generator Excitation System

a) Brushless b) Accuracy of AVR within ± 0.5% c) AVR Reference voltage set point adjustable range - 15% to + 10% of nominal voltage for all loads d) Ceiling voltage greater than 150% e) Nominal exciter response ratio greater than 3 per second

8. Brushless Excitation System

Sufficient parallel diodes to allow for 20% failure without derating exciter

9. Auxiliary Power a) 11 KV ± 10%, 3 phase, 3 wire, 50 Hz, non-effectively earthed b) 3.3 KV ± 10%, 3 phase, 3 wire, 50 Hz, non-effectively

earthed c) 415V ± 10%, 3 phase, 4 wire, 50 Hz effectively earthed d) 220V ± 10% DC, 2 wire, ungrounded



DCPL-11Z02


10.

11.

12.

13.

HP/LP Bypass requirement Turbine Mode of Operation VWO Capacity Over Pressure operation

60% Boiler MCR HP bypass & matching LP bypass for parallel operation with T.G. under part load/house load condition. a) Modified sliding pressure operation. b) Capable of sustaining full load dump to house load with

HP/LP bypass as well as sustained operation at this condition.

Bidder to indicate data Not less than 105% of Turbine MCR. Turbine shall be capable of permitting a maximum sustained overpressure of at least 10% of the design turbine inlet steam pressure.

It should be latest state of the art international technology oriented. The modified sliding pressure operation stands for :

• 0% to 35%/40% TMCR : Constant Pressure Operation.

• 35%/40% to 90%TMCR : Sliding Pressure Operation.

• 90% TMCR to VWO : Constant Pressure Operation.

Entire BTG Package shall be suitable to operate continuously under VWO capacity.

VOLUME : II-C

SECTION-II

FEED WATER HEATERS AND DEAERATOR


CONTENT CLAUSE NO. DESCRIPTION PAGE NO. 1.00.00 GENERAL INFORMATION V.IIC/S-II : 1 2.00.00 CODES AND STANDARDS V.IIC/S-II : 1 3.00.00 EQUIPMENT AND ACCESSORIES TO BE FURNISHED V.IIC/S-II : 2 4.00.00 GENERAL PERFORMANCE REQUIREMENT V.IIC/S-II : 2 5.00.00 CLOSED FEED WATER HEATERS V.IIC/S-II : 3 6.00.00 DEAERATOR V.IIC/S-II : 7 7.00.00 INSTRUMENTATION AND CONTROL V.IIC/S-II : 10 8.00.00 DRAWINGS, DATA AND INFORMATION REQUIRED V.IIC/S-II : 10 ATTACHMENT ANNEXURE-I SPECIFIC DESIGN CRITERIA FOR V.IIC/S-II : 11 FEED WATER HEATERS & DEAERATOR


VOL-II-C-SEC-II - 1

DCPL-11Z02

VOLUME : II-C

SECTION-II


1.00.00 GENERAL INFORMATION 1.01.00 The feed heating system for each unit shall consist of low pressure (L.P)

heaters, one (1) deaerator and high pressure (H.P.) heaters and compatible with the turbine-generator (TG), Steam-Generator combination offered by the Bidder. The boiler feed pumps will take suction from the Deaerator and pump the feed water to boiler through the high-pressure heaters. The condensate extraction pumps will take suction from condenser hot well and pump the condensate to deaerator through L.P. heaters. The heating steam for the high-pressure heaters, deaerator and low-pressure heaters will be supplied from different extraction stages of the turbine. The deaerator will also be given pegging connections from unit auxiliary steam header and cold reheat line.

1.02.00 The drains shall be cascaded from heater to heater. All high-pressure heater

drains shall be returned to the deaerator with an alternate provision for returning to condenser via flash tanks/ boxes. The low-pressure heater drains shall be cascaded to the condenser. All heater drain flash boxes/tanks, traps and orifices required for this purpose shall be provided.

2.00.00 CODES AND STANDARDS 2.01.00 In addition to the requirements spelt out in Section-IV of Vol.IIA, the

feed-water heaters and deaerator shall conform to the latest editions of the following standards and codes :

2.01.01 Heat Exchanger Institute (HEI) Standards. 2.01.02 ASME Boiler and pressure vessel code - Section-VIII. 2.01.03 American National Standards (ANSI) on a) Steel Pipe Flanges and Flanged Fittings (B 16.5) b) Steel Fittings S.W. and Threaded (B 16.11) c) Butt welding ends-Pipe, valves, & fittings (B16.25). 2.01.04 PTC 12.1 : ASME Performance Test Codes for Closed Feed Water

Heaters PTC 12.3 : ASME Performance Test Codes for Closed Feed Water

Deaerator 2.01.05 ASME - TDP [Part I] : Prevention of Water Damage to Steam Turbines


VOL-II-C-SEC-II - 2

DCPL-11Z02

2.02.00 All equipment covered under this section shall comply with all the requirements of the latest edition of ASME Boiler and Pressure Vessel Code, Section-VIII.

2.03.00 The equipment or portions thereof which come under the purview of Indian

Boiler Regulations (IBR) shall specifically meet all such requirements of IBR which are more stringent than ASME, or any other international standards like BS, DIN, JIS etc.

2.04.00 For items more specifically addressed in Heat Exchange Institute Standards,

these standards shall apply for parts if the requirements are more conservative than the ASME Code.

3.00.00 EQUIPMENT AND ACCESSORIES TO BE FURNISHED 3.01.00 The feed heating cycle of each unit shall consist of One (1) DEAERATING

HEATER with storage tank and vent condenser, (if any), complete with all internals, fittings, gauges, instruments etc.

3.02.00 Required numbers of shell & tube type HIGH PRESSURE FEED WATER

HEATERS with all fittings, gauges, instruments etc. 3.03.00 Required numbers of shell & tube type LOW PRESSURE FEED WATER

HEATERS with all fittings, gauges, instruments etc. 3.04.00 Necessary fittings for all heaters such as safety relief valves, level indicating

gauge glasses, level switches, vent and drain valves, local instruments etc. 3.05.00 Necessary eye bolts, lugs, rollers and rails for shell/tube withdrawal of

horizontal closed feed water heaters. 3.06.00 Foundation bolts, nuts, inserts, embedded plates, rollers, bearing pads,

sleeves etc. as required. 3.07.00 Complete insulation as required for all the heaters and deaerator covered

under this section. 4.00.00 GENERAL PERFORMANCE REQUIREMENT 4.01.00 The feed heating system shall be capable of raising the temperature of feed

water from that in the condenser to the final optimised value specified at the outlet of the top high pressure heater with turbine generator (T.G) set operating at rated parameters.

4.02.00 The extraction steam pressures and flows shall be determined by the Bidder

by working out the turbine cycle heat balance. 4.03.00 The maximum oxygen content of the feed water discharge from the deaerator

without chemical dosing shall not exceed 0.005 cc/litre at all loads upto and including the rated capacity. The carbon-di-oxide content of the feed water discharge shall be nil.


VOL-II-C-SEC-II - 3

DCPL-11Z02

4.04.00 Heaters shall be capable of operation under the condition of preceding lower pressure heater taken out of service. The heaters shall be designed to accommodate increased steam and drain flows (for the next higher pressure heaters and the deaerator) in such an event. Bidder shall submit performance data on affected heaters in the train when one heater is removed from service. Data shall be calculated for conditions when each of the heaters is removed from service individually and/or in-group, and the remaining heaters are on line. Besides submission of off-performance data, the Bidder shall also indicate limitation of service, if any, during such condition. The deaerator shall be designed for the maximum incoming steam flow when none of the L.P. heaters is working under H.P/L.P Bypass condition.

4.05.00 During H.P. - L.P. By-pass operation, feed water shall be heated in deaerator

to a minimum permissible temperature as per boiler requirement. Minimum acceptable H.P. heater outlet temperature during turbine low load operation shall be finalised as per boiler requirement.

4.06.00 The operation of the deaerator shall be stable and free from vibration etc.

when subject to transient condition which may occur at full load trip out conditions of the T.G. and during introduction of alternative steam service.

4.07.00 All equipment warrant high reliability, low down time and ease of

maintenance. 4.08.00 Equipment offered shall have an operating noise level as per ISO -- 85.

However, noise level should not exceed 85 dBA at 1 m distance. 5.00.00 CLOSED HEATERS 5.01.00 Design Requirements 5.01.01 The heaters shall be of surface type. Water shall flow inside the tubes and the

heating steam outside the tubes. High & Low pressure heaters shall be horizontal as per Manufacturer's standard proven practice. Heaters shall have integral drain cooling and desuperheating sections, as required.

5.01.02 The lowest pressure heater may be located in the condenser neck in case

that is the standard arrangement of the manufacturer. In such a case, a separate external drain cooler may be provided instead of being integral to the heater. L.P Heater mounted inside the condenser neck shall be provided with required shell attachments for supports and for closure plates for sealing the penetrations through the condenser shell. The heater shall also be provided with antiflash baffles to protect the turbine from water ingress. Arrangement for heater tube withdrawal shall be provided; piping connected to the heater shall be so routed as to facilitate the tube withdrawal without dismantling the pipes.

Start-up vent from the heater mounted in condenser neck shall be provided

with orifice plate. 5.01.03 Bidder shall select the terminal temperature difference and the drain cooler

approach of the feed heaters keeping in mind the overall economy. However, following shall be the minimum criteria.


VOL-II-C-SEC-II - 4

DCPL-11Z02

a) H.P. heaters shall be provided with desuperheating and drain cooling zones in addition to the condensing zone. The maximum terminal temperature difference and maximum drain cooler approach shall be as per the attached Annexure-I.

b) L.P. heaters shall be provided with drain cooling zone in addition to

the condensing zone. Terminal temperature difference shall be as per the attached Annexure-I.

c) Heat transfer area shall be calculated considering 10% of the tubes

plugged. Fouling factor shall be taken as per the recommendation of the Heat Exchanger Institute, USA.

5.01.04 The L.P. heaters shall be designed for the shut-off pressure developed by the

condensate pumps on the tube side. Relief valves to be provided on HP heaters and the design pressure of HP heaters shall same as design pressure of boiler feed water discharge piping as stipulated in power cycle piping chapter. The shell side shall be designed for the maximum extraction steam pressure (with 10% margin at VWO condition or 0.1Mpa (a)), whichever is higher and full vacuum.For heaters taking extraction from CRH line, the maximum expected HPT exhaust pressure shall be taken into account. The shell side design flow shall be calculated for the normal operating as well as abnormal conditions as specified and for a tube sheet leakage of 20% of the condensate/boiler feed water flow. Nozzles shall be sized liberally considering various modes of operation and shall be subject to approval by Purchaser. The tube side velocity shall be limited to 2.5 m/sec under all operating conditions. Steam nozzle location, steam distribution dome and velocity of steam should be as per Para 2.7 and 2.8 of HEI standards.

Corrosion allowance of 3.2 mm shall be applied to the design thickness of

each heater shell and water box. Tube thickness shall be increased to compensate for tube wall thinning.

5.01.05 About 0.5% of the steam entering a heater shall be vented (from its

condensing zone) to the condenser and orifice plates shall be fitted in the vent pipe work to control the flow. Care should be taken to prevent accumulation of pockets of gas by positioning the vents in such a manner that every part of the tube nest is swept by steam. Each heater shall be separately and continuously vented to the condenser. Cascading of vents from heater to heater will not be permitted. The vent valves shall always remain open, whenever a heater is in service.

5.01.06 Each of the L.P. and H.P. feed heaters shall have individual motorised bypass

arrangements with isolation to enable it to be taken out of service without necessitating the shut down of the turbine generator set.

5.01.07 Self-sealing type hand holes shall be provided on the H.P. heater water box

for access to all the tubes. A skirt shall be provided around the tube bundle to shield during a gas cutting of the shell if required for removal of the tube bundle.


VOL-II-C-SEC-II - 5

DCPL-11Z02

5.01.08 The arrangement of the feed water heater internals shall be such as to minimise rapid fluctuations of heater level during operation and the heaters shall be designed to operate without excessive noise and vibration.

5.01.09 Shell side relief valves shall be sized for 10% of the feed water flow, or

maximum feed water inflow to shell due to the rupture of two (2) nos. tubes, whichever is greater, at 10% accumulation. Tube side relief valves shall be provided to guard against overpressure from water expansion when inlet and outlet valves are closed. The shell side relief valve set pressure shall be above the maximum working pressure of the extraction steam line, connected to the feed heater, in all possible operating conditions.

5.01.10 Necessary vent and drain connections with valves shall be provided. Vents

and drains on the feedwater side of H.P. heaters shall be provided with double valves.

5.01.11 The heaters shall be designed for the minimum tube side pressure drop, and

the same shall be indicated (for rated operating condition) in the Bid. 5.01.12 Each of the LP/HP heater shall have 10% plugging margin and sufficient Nos.

of metallic plugs shall be supplied with heaters. 5.02.00 Materials and Construction 5.02.01 The water box for the high pressure heaters shall be of forged construction

and welded to the shell. The low-pressure heaters may be of bolted head or with welded water box. For bolted head type, copper jacketed gaskets or other metallic packing of approved quality shall be used.

5.02.02 The heater shells shall be of carbon steel welded construction. The tubes

shall be of U-type. The L.P. heater tubes shall be roller expanded into the tube plates provided with at least two grooves.

The H.P. heater tubes shall be joined to the tube plates by welding to the

stainless steel overlay by a proven technique. The Bidder shall, in his proposal, give complete description of the process adopted.

The tube nest shall be supported by baffles, which shall prevent vibration and

also ensure an even distribution of steam. Stainless steel impingement plates shall also be provided at all steam and water inlet branches to prevent direct impingement and wear of the tubes. The water box baffle plates shall be positioned to give good flow distribution through the heater tubes. The heaters shall be designed for most economical length and shall have suitable lifting arrangement such that a heater or shell can be removed for maintenance purposes.

5.02.03 The tube sheet shall be of forged carbon steel for L.P. heaters. For H.P.

heaters, the tube sheet of forged carbon steel shall be overlaid first with one layer of SS-309, and then another layer of SS-308, to a total thickness of overlay not less than 7 mm. The feed water heater tubes shall conform to the applicable requirements of ASME specification. Seamless or welded type stainless steel (SS-304L) tubes shall be provided. Details of experience of the bidder with the type of tubes provided (seamless or welded) shall be furnished in the bid. Minimum tube dia shall be 5/8" and thickness shall not be


VOL-II-C-SEC-II - 6

DCPL-11Z02

less than 20 BWG. Stress relieving of U-bends shall be carried out up to a distance of 150 mm from bend area. Drawing and bending lubricants shall be non-chlorinated.

Bolting material, not in contact with steam or water, shall be ASTM A-193

Grade B7. For other bolting, manufacturer's standard corrosion resistant material shall be used.

5.02.04 H.P. water box nozzle connections shall be butt-weld type for sizes above 50

mm and socket weld for sizes below 50 mm. Other connections may be flanged type.

All flanged connections shall be of the bolted type and the use of studs shall

not be permitted unless with special approval. 5.02.05 All tube holes in the tube sheets, baffles and supports shall be deburred. 5.02.06 Insulation cleats shall be provided on shell and water box. 5.02.07 The interior surfaces of all the heaters shall be cleaned of all mill scale. The

exterior surfaces shall be painted as required. 5.02.08 Material of construction for different parts of the drain cooler shall be identical

to those specified for LP heaters. 5.02.09 Design Pressure and temperature shall be followed as per HEI, ASME and

should be tested as per relevant IBR provision. 5.03.00 Tests 5.03.01 At Manufacturer's Works All heaters shall be subjected to manufacturer's standard shop inspection and

tests in accordance with applicable provision of IBR and ASME "Code for unfired pressure vessel" Section-VIII. Mill certificates for the materials for heater shell, tubes, support plates, tube sheets, water boxes, flash tanks etc. shall be submitted to the Purchaser.

Heat exchanger tubes and water boxes shall be tested by one of the following

methods for cracks, imperfections etc. : a) Back light b) Magnetic particles c) Dye penetrant Each tube shall also be "Eddy Current" tested. Additionally, the following tests

shall also be performed on each lot of Heat Exchanger tubes : a) Microscopic b) Chemical Analysis


VOL-II-C-SEC-II - 7

DCPL-11Z02

c) Yield strength d) Flattening e) Flanging Hydrostatic testing of the heat exchangers shall be done in accordance with

ASME TEST CODE for Unfired Pressure Vessels Section-VIII and I.B.R. as applicable.

5.03.02 At Site The feed water heat exchangers shall be field tested in accordance with

ASME Performance Test Code PTC 12.1 to determine the following : a) Temperature rise of the feed water/condensate at guaranteed capacity

points. b) Friction drop in the water circuit. The supplier shall furnish all instruments necessary to perform the above

tests. 6.00.00 DEAERATOR 6.01.00 Design Requirement 6.01.01 Deaerator shall be capable of operating satisfactorily with two of the adjacent

L.P. heaters out of service. Adequacy shall also be checked for the condition of H.P. - L.P. bypass when no feed heating is taking place in L.P. heaters and also for initial heating, steam blowing, initial commissioning etc.

Storage tank shall be fabricated at shop in minimum number of sections (to

be determined on the basis of the size of tank and the transportation limitations) so as to minimise fabrication work done at site.

6.01.02 A horizontal, direct contact, spray-cum-tray type single deaerating vessel

mounted on a horizontal storage tank shall be provided. Spring loaded nozzles for spray control shall be provided for guaranteed operation of the deaerator for a flow range from 100% to 30% without water hammering. The trays shall be provided for final stages of deaeration and shall be of rigid clamped type. The terminal temperature difference shall be zero at all load conditions. The deaerator will be operated for variable pressure. During load swing, cold condensate at hot well temperature and 110% of normal flow may enter the deaerator. The extraction steam during such operation may be zero such that flash steam from the storage tank will flow to the dearator. For this purpose adequately sized vent pipe from the storage tank to the deaerator and internal water and steam distribution shall be provided.

Alternatively, a spray type (stork or equivalent) deaerator, which otherwise

fulfills all design and performance requirements stipulated here in, may be offered.


VOL-II-C-SEC-II - 8

DCPL-11Z02

6.01.03 If the Deaerator is provided with an external shell and tube type vent condenser, the same shall condense all vapour and vent out non-condensable gases to atmosphere. The vent condenser shall minimise loss of steam through the vent connection under all conditions of operation by providing at least 1°C sub-cooling of vented vapours over entire load range. The vented gases shall be free of any visible vapour.

6.01.04 The deaerator shall be capable of deaerating all the incoming condensate,

H.P. heater drips and emergency make up water at a rate adequate to provide boiler feed to match the boiler MCR requirements continuously. The storage tank shall hold sufficient feed water as per the norms laid down in the attached Annexure-I.

6.01.05 The dissolved oxygen content at the discharge from the deaerator without

chemical dosing shall not be more than 0.005 cc/litre in the boiler feed water at all loads, up to and including the rated capacity. The deaerator shall also effectively remove even traces of any other dissolved gases such as CO2 likely to be present in the condensate/feed water.

6.01.06 The deaerator is proposed to be located at an higher elevation with respect to

turbine operating floor. Bidder, however, shall check and confirm the adequacy of this level considering the system offered, types and requirement of Boiler Feed Pumps considered etc. such that system can operate safely and smoothly under all operating conditions, abnormal and transient conditions and also for full load throw off condition.

6.01.07 The operation of the deaerator shall be stable and free from vibration and

water hammer when subjected to pressure decay which may occur at full load trip out conditions of the T.G. and during introduction of the alternative steam service.

6.01.08 For supporting of the storage tank, one support leg shall be fixed and the

other shall be sliding type to accommodate expansion of the equipment. The supply shall also include suitable ladder, platform & hand railing for access to various parts of the deaerating heater.

The deaerator proper may be supported from the storage tank, or

independently from floor level and all support structures in either case shall be included in the Bid.

6.01.09 The following connections shall be provided over & above condensate/feed

water inlet and outlet connections : a) A perforated pipe connection of suitable size for steam supply for

initial heating and deaerating of water stored in feed storage tank at the time of starting of the unit.

b) Connections on the tank for boiler feed recirculation, chemical dosing

etc. c) Drain connections with valve and drain pipe to the flash box at ground

floor level.


VOL-II-C-SEC-II - 9

DCPL-11Z02

d) Suitable over-flow connection on the feed storage tank including control valve and motorised by-pass valve.

e) H.P. Heater drip inlet. f) Extraction/pegging steam inlet. g) Safety valve connections. h) Vent connections. i) Sufficient number of inspection openings/man-holes (of minimum 600

mm diameter) with suitable covers for easy cleaning, inspection and maintenance. Covers for these openings/man-holes shall be hinged type.

j) All local/remote instrument connections including root valves. k) Stand pipe connections. l) Other connections as necessary. Number, size, location and orientation of the connections, as necessary, shall

be decided by the supplier considering the performance of the deaerator. If found necessary, it shall be possible to reorient the nozzle connections of deaerator so as to match the layout of associated piping.

6.01.10 Anti-vortex baffle together with a coarse strainer shall be provided for feed

water outlet. Safety relief valve/s with adequate compensating pad for full relieving capacity at the worst operating conditions shall be included.

6.02.00 Materials of Construction Following materials of construction shall be used for deaerator : a) Shell and heads : ASTM : A-285 Grade C or equivalent b) Spray Nozzles : 304 stainless steel c) Trays : 304 stainless steel d) Tray supports : Stainless steel e) Internal bolting : Stainless steel f) All metal parts in contact with non-condensable vapour shall be of

type 316 stainless steel. g) Hardened 400 series stainless steel impingement plate shall be

provided for the flashed drain inlet from the high-pressure heaters and boiler feed pump recirculation.

6.03.00 Tests 6.03.01 At manufacturer's works


VOL-II-C-SEC-II - 10

DCPL-11Z02

Deaerating heater, vent condenser (if provided) and storage tank shall be

shop inspected during fabrication in accordance with applicable provisions of ASME "Code for unfired pressure vessel", Section-VIII. Mill Test Certificates for all the materials used shall be submitted to the Purchaser. Hydrostatic testing for deaerating heater and vent condenser (if provided) shall also be carried out as per the above codes.

6.03.02 At Site Field Tests shall cover the determination of dissolved oxygen (ASTM-D888)

and free carbon-di-oxide (APHA) in deaerator effluent along with thermal and hydraulic performance of the deaerator. All performance shall be tested and evaluated as per ASME PTC 12.3 (latest edition).

7.00.00 INSTRUMENTATION & CONTROLS Refer Volume : IIE 8.00.00 DRAWINGS, DATA AND INFORMATION REQUIRED 8.01.00 Calculation for thermal design basis for all the heaters indicating clearly the

basis of establishing surface area. 8.02.00 Sizing calculations of the control valves along with the characteristic curves. 8.03.00 Equipment load list and foundation design. 8.04.00 Other drawings & data as requested in lead specification Volume: IIA. 8.05.00 Genearl Arrangement drawings of Deaerator & Heaters


VOL-II-C-SEC-II-ANX-I - 11

DCPL-11Z02

SPECIFIC DESIGN CRITERIA FOR


SL. NO. ITEM CRITERIA REMARKS

1.00.00 Regenerator Cycle : Design shall conform to All heaters and ASME-TDP-I (latest edition). deaerator shall be

designed under vacuum condition also. All instrumentations shall be designed accordingly.

2.00.00 Type of Heaters : LP & HP Heaters - Horizontal shell & tube type. Deaerator - Spray - cum - tray type or Spray type 3.00.00 Number of Heaters : Least number to be decided by Bidder during heat balance optimisation. 4.00.00 Design TTD (Terminal Tempe- rature difference) : Heater Section : 3°C to 0°C Drain Cooler Section : 6°C(maximum). 5.00.00 Design Extraction Line Pressure drop : 5% 6.00.00 Design standard : As per Heat Exchanger Institute, USA or equivalent. 7.00.00 Steam Parameters : a) Normally variable pressure from uncontrolled turbine extraction b) Regulated steam admission to deaerator from auxiliary steam as required during part load operation c) Parameters to be decided by Bidder during heat balance Optimization 8.00.00 Metallurgy of Tubes : SS 304L


VOL-II-C-SEC-II-ANX-I - 12

DCPL-11Z02

SL. NO. ITEM CRITERIA REMARKS

9.00.00 Deaerator Storage : 6 minutes at Boiler MCR between Tank Capacity # normal and lowest water level. 10.00.00 Oxygen & CO2 Content at the outlet of . Deaerator : 0.005 cc/litre O2 (maximum) without chemical dosing CO2 – Nil 11.00.00 Velocity of water flow through tubes : 2.5 m/sec (max.) 12.00.00 Design Pressure - Tubes : Pump shut-off pressure - Shell : Not less than maximum Extraction steam

pressure(10% margin at VWO condition or 0.1Mpa (a) whichever is higher) and full vacuum. For heaters taking extraction from CRH line , the maximum expected HPT exhaust pressure shall be taken into account.

# Storage Tank total internal volume shall be such that, the capacity at the normal water

level is not more than that of 2/3rd of it’s capacity and the capacity at the lowest permissible level should not be less than 25% of it’s capacity.

VOLUME : II-C

SECTION-III

POWER CYCLE PUMPS, DRIVES & ACCESSORIES


CONTENT CLAUSE NO. DESCRIPTION PAGE NO. 1.00.00 GENERAL INFORMATION V.IIC/S-III : 1 2.00.00 CODES AND STANDARDS V.IIC/S-III : 2 3.00.00 EQUIPMENT AND ACCESSORIES TO BE FURNISHED V.IIC/S-III : 2 4.00.00 GENERAL PERFORMANCE REQUIREMENT V.IIC/S-III : 5 5.00.00 BOILER FEED PUMP DESIGN AND CONSTRUCTION V.IIC/S-III : 11 6.00.00 CONDENSATE EXTRACTION PUMP DESIGN AND CONSTRUCTION V.IIC/S-III : 25 7.00.00 INSTRUMENTATION AND CONTROL V.IIC/S-III : 26 8.00.00 INSPECTION AND TESTING V.IIC/S-III : 26 9.00.00 DRAWINGS, DATA AND INFORMATION REQUIRED V.IIC/S-III : 27 ATTACHMENT ANNEXURE-I SPECIFIC DESIGN CRITERIA FOR POWER CYCLE PUMPS V.IIC/S-III : 29


VOL-II-C-SEC-III/1

DCPL-11Z02

VOLUME : II-C

SECTION-III

POWER CYCLE PUMPS, DRIVES & ACCESSORIES

1.00.00 GENERAL INFORMATION 1.01.00 Boiler Feed (B.F) Pumps and Drives 1.01.01 2 x 50% capacity steam turbine driven pumps (with shaft driven suction booster

pumps, drives and accessories, if required) and 1 x 50% or 2 x25% or 1 x30% capacity electric motor driven pumps with shaft driven booster pumps and hydraulic coupling shall be installed for supplying feed water to each steam generating unit. Two (2) turbine driven pumps will be operating normally while the third electric motor driven pump shall remain as a standby unit and will come into operation automatically in case any of the working pumps fail.

1.01.02 The Boiler feed pumps shall receive the suction water from deaerating heater

storage tank and then pump it through high pressure feed water heaters to the steam generator.

1.01.03 The deaerator shall be supplied with extraction steam from the turbine and shall

normally operate at a variable pressure depending on the extraction pressure at different loads. A steam connection from the auxiliary steam header/cold-reheat pipe shall be provided for initial heating and deaeration at start-up as well as Pegging at low extraction steam pressure. However, the boiler feed pumps shall be capable of withstanding transient instabilities in the suction pressure caused due to load swing of the turbine generator from full load to no load and interruption of steam supply to the deaerator. Boiler feed pumps shall also be adequately designed for turbine by-pass operation.

1.01.04 The pumps shall be designed for efficient and reliable operation and shall be of

proven design with at least five years of satisfactory operating experience. 1.02.00 Condensate Extraction Pumps and Drives 1.02.01 Each Unit shall be provided with three (3) nos. 50% capacity condensate

extraction pumps (2 working and 1 standby). Any two of the pumps shall be capable of handling the full condensate from the condenser to the deaerator through L.P. heaters, gland steam condenser etc. Each Pump capacity shall be calculated considering equal flow sharing by the two running pumps and the maximum condensate flow which may be encountered in the various modes of operation specified in attached Annexure-I.

1.02.02 The pumps shall be required to handle hot condensate at or near saturation

temperature and shall be designed for very low NPSH service. The suction specific speed selected shall be suitable to permit part load operation as per system requirement without any trouble.

1.02.03 The pumps shall be designed to withstand transient due to load swing of the


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unit from full load to no load. Adequate design margins shall be provided in the pumps for turbine bypass operation.

2.00.00 CODES AND STANDARDS 2.01.00 In addition to the requirements spelt out in Section-IV of Volume: IIA all the

equipment systems and work covered by this section shall conform to the latest editions of following codes and standards :

i) American National Standard Institute (ANSI), as specifically referred to. ii) PTC - 6 & IEC-45 : Steam Turbine iii) PTC 8.2 : ASME Performance Test Codes for Centrifugal Pumps. iv) Electrical Power Research Institute (EPRI). v) AGMA : Gear box for BFP Drive Turbine. All equipment covered by this specification shall comply wit all applicable laws

and statutory regulations, India Electricity Act etc. 3.00.00 EQUIPMENT AND ACCESSORIES TO BE FURNISHED 3.01.00 Boiler Feed Pumps and Accessories The equipment and accessories for each boiler feed pump and drive shall

include, but not be limited to, the following : 3.01.01 Steam turbine driven boiler feed pumps and booster pumps specified herein for

both the TG sets together with all accessories and auxiliary equipment including gear boxes required to make a complete and well integrated unit to satisfy the scope of this specification shall include but will not be limited to the following (for each pump unless indicated otherwise) :

a) Balance chamber leak-off flow orifice for boiler feed pump, if required. b) Suitable seal system as required by the design of the booster pump and

main pump shaft seals along with cooling system. c) Supply of disconnect coupling, if required for the turbine drive main feed

pumps. All metal flexible coupling between gearbox and booster pump and between gear box and drive turbine. Coupling guard for each coupling.

d) Sole plates, pin and key blocks or other support structure and a

common base plate (with foundation anchor bolts/inserts, drip lip and drain) for booster pump and gearbox, motor drive.

e) Interstage bleed-off connection to supply water to reheat steam de-

superheater and kicker stage to supply water to superheater attemperation (Boiler feed pump only).

f) Removable lagging and insulation (both for boiler feed pump and


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booster pump). g) Duplex R.T.D./thermocouples in all journal, thrust bearings and pump

barrels. h) A complete self-contained lubricating oil system including tanks, pumps,

coolers, strainers, piping, all instruments and control hardwares etc. for the lubrication of the main pump, booster pump, gearbox and the auxiliary drive turbine.

i) Duplex type basket strainer for installation ahead of the booster pump

suction along with differential pressure switch. Pressure relief valve on pump suction, downstream of the isolation valve.

j) Individual pump recirculation control valves and pressure break down

orifices, as necessary to pass the minimum flow required. k) Local instruments, local gauge board and instruments to be mounted on

the gauge board as required. l) Pump warm-up orifice (s) for boiler feed pump, if required. 3.01.02 Each motor driven boiler feed pump and booster pump set specified herein

together with all accessory equipment, including gear boxes and hydraulic couplings, required to make a complete and well integrated unit to satisfy the scope of this specification shall include but not limited to the following (for each pump unless indicated otherwise) :

a) Pump warm-up orifice(s) and control valve with all control hardware, if

any, for boiler feed pump, if required. b) Balance chamber leak-off flow orifice for boiler feed pump, if required. c) Temperature sensing type seal control system for the boiler feed pump

complete with temperature controller, sensing elements, control valves, filters, air filter regulators, complete piping from the condensate source and suitable seal system as required by the design of the booster pump shaft seals.

d) Flexible spacer type shaft couplings with coupling guard. e) Sole plates, pin and key blocks or other support structure, and a

common base plate (with foundation anchor bolts/inserts, drip and drain) for the unit consisting of the main pump, booster pump (if applicable), hydraulic coupling, gear box and motor drive.

f) Interstage bleed connection to supply water to reheat steam de-

superheater and kicker stage to supply water to superheater attemperation (Boiler feed pump only).

g) Removable lagging and insulation for both boiler feed pump and booster

pump. h) A complete self-contained lubricating oil system including banks,


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pumps, coolers, strainers, piping, etc. along with all necessary instrumentation and control hardwares for the lubrication of the main pump hydraulic coupling gearbox and the drive motor.

i) Duplex RTD/thermocouples in all journals, thrust bearings and pump

barrels. j) Duplex type basket strainer for installation ahead of the booster pump

suction along with differential pressure switch. Pressure relief valve on pump suction, downstream of the isolation valve.

k) Modulating type Recirculation control valves and pressure break down

orifices, as necessary to pass the minimum flow required for the pump. l) Local instruments, local gauge board and instruments to be mounted on

the gauge board as required. 3.01.03 Each steam turbine drive for combined boiler feed pump, booster pump unit as

described in Clause 3.01.01 shall include the following : a) Steam admission pipes from the following sources to the auxiliary

turbine along with individual steam admission valves : i) IP or LP, turbine extraction system - Normal source. ii) Cold reheat line terminal connection - Alternative source. b) Exhaust ducts from the auxiliary turbines along with metallic expansion

joint and butterfly valve. The exhaust duct shall be self-draining to the condenser.

c) Gland sealing steam supply piping from main turbine gland sealing

system and return piping to gland steam cooler for main steam turbine complete with all fittings, valves, necessary instrumentation and control hardwares to make the system complete in all respects.

d) Complete insulation inclusive of special material, if any, for the auxiliary

turbines and piping in the scope of this specification. 3.01.04 Drive motor for the motor driven boiler feed pump. 3.02.00 Condensate Extraction Pump and Accessories Condensate Extraction pumps together with all accessories required to make

complete and well integrated units to satisfy requirements of the specification, including but not limited to the following (for each pump, unless otherwise noted).

3.02.01 Drive motor 3.02.02 Pump and motor coupling 3.02.03 Strainer and Expansion Joint (if required) before pump suction.


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3.03.00 All instrumentation and control as specified and/or as required. The scope shall

also include initiating contacts for the alarms and interlocks. A gauge board shall be supplied with each pump housing instruments as specified in Volume: IIE.

3.04.00 Foundation ring/frame with bolts, nuts, sleeves etc. 4.00.00 GENERAL PERFORMANCE REQUIREMENT 4.01.00 Boiler Feed Pump 4.01.01 Capacity and discharge pressure of the pumps shall be selected to meet the

requirements of the steam generator in line with the requirements specified in Annexure-I attached. The Bidder shall furnish the pump sizing calculation with the Bid.

4.01.02 The boiler feed pump shall be driven by steam turbine and squirrel-cage

induction motor through a variable speed hydraulic coupling. Appropriate step-up gears as required shall be provided.

4.01.03 Each pump shall exhibit the same type continuously rising characteristic from

rated duty point to shut-off. The pumps should be capable of parallel operation without instability at all speeds and share equal load. Shut-off head shall not, however, be less than 120% and shall not be more than 130% of the head developed at pump design point.

The pumps shall have their best efficiency at the normal duty point, i.e.,

corresponding to 660 MW load, 1% (of throttle flow) make up and design CW temperature of 33°C. The Boiler Feed Pump guaranteed efficiency at its rated condition shall not be less than 80%.

4.01.04 The pump shall be designed for working at its operating temperature without

setting up destructive temperature strain causing warping, buckling, misalignment, rubbing or other objectionable effects.

4.01.05 The pumps shall be capable of accepting, without damage, any transient

reduction in suction pressure including dry run condition causing cavitation condition and shall accept, without distress, the re-establishment of normal suction conditions following the transient, with no necessity for a pump shut down.

4.01.06 The deaerator storage tank is proposed to be located at higher elevation.

Bidder shall check the requirement of NPSH against available NPSH considering the worst transient situation of load dump. Bidder to ensure that adequate margin over the required NPSH shall be available under worst condition for safe and trouble free operation. The booster pump should be directly driven by the boiler feed pump. The head developed by the booster pump shall be sufficient to give adequate NPSH at the main pump suction.

Bidder shall furnish necessary calculations to establish the availability of excess

NPSH over the actual NPSH requirement of the pump, which shall be not less


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than 1.8 times the NPSH corresponding to 3% head drop. Suction specific speed for B.F.P. and Booster Pumps must not exceed 9500 US

Units. 4.01.07 Pumps shall be capable of withstanding reverse rotation for a limited time

required to close discharge shut off valve following an emergency failure of the main discharge Non-Return Valve of a standby pump. All bearings & mechanical seals shall be capable of withstanding this operation.

4.01.08 The capacity, head and efficiency of the pumps shall be guaranteed within the

tolerances stipulated by Hydraulic Institute Standards, USA or any other International Standard.

4.01.09 The pump and drive assembly shall be so constructed that dismantling and

repairing may be accomplished without difficulty. Complete interchangeability of parts between the pumps shall be ensured.

4.01.10 Pump and drive assembly shall run smooth, free from undesirable vibration,

noise and leaks. Acceptable peak-to-peak vibration limits of the Hydraulic Institute Standards of USA will be applicable.

4.01.11 The Units shall be so arranged that start-up, running and shut down operation

may be carried out from the central control room. Necessary interlock and provisions shall be made so that the standby pump will come into operation automatically and immediately without any thermal shock whenever any operating pump trips.

4.01.12 Speed control range of the B.F. Pump drive unit (both turbine and motor) shall

cover the entire range of boiler feed pump operation, from minimum flow (i.e. pumps on recirculation) to the design head-capacity point with at least 5% margin on pump speed both on the high and low sides.

4.01.13 Pumps shall be capable of re-starting following a hot or warm shutdown without

recourse to barring or warming up. Bidder shall indicate the maximum allowable conditions for restarting such as maximum casing differential temperature and maximum difference between casing temperature and incoming water temperature.

4.01.14 Boiler Feed Pump first stage impeller and if applicable, the booster pump shall

be so designed that wear due to cavitation will not restrict its service life to less than 40,000 - 45,000 running hours when operating under steady state design suction condition.

4.01.15 Boiler Feed Pumps and auxiliaries shall be adequately designed to meet the

Turbine HP and LP by pass condition without any problem. 4.01.16 The pumps shall be capable of safe, proper and continuous operation at

speeds upto 10% above full rated speeds, provided that the minimum discharge flow shall not be less than that required to prevent over heating.

The turbine - driven boiler feed pumps shall be capable of with standing an 10%

overspeed under conditions leading to the overspeed trip of the drive turbine.


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Bidder shall indicate the required operating speed and the steam/power

consumptions of the drives throughout the pump range of operation. 4.01.17 Bidder shall guarantee the steam consumptions (power consumption for motor

driven pumps) at the rated condition. This guarantee figure shall account for all losses in the driven, gear trains, hydraulic couplings (used on electric driven pumps) etc.

The drive motor shall be so selected that a margin of at least 10% is provided

over the total power required by the B.F. Pump, 15% for Booster Pump, Oil Pump and losses in the gear box and hydraulic coupling, at the rated condition of the pump. It should also be checked that when the pump operates with control valve stuck open, the power requirement is lower than the drive power, irrespective of whether the pump is working singly or in parallel with the other pumps. Detailed calculation for sizing of motors shall be submitted to the Employer for approval.

4.01.18 Pumps shall have short, stiff shafts, with least number of stages for the

specified duty. The critical speed of the rotor assembly, in dry as well as water filled conditions, shall be beyond the maximum possible running speed by at least 30%, even after considering power supply to pump drive motor at 51.5 Hz.

4.01.19 Plain cylindrical pressure fed journal type bearings and tilting pad, double acting

100% thrust bearing shall be provided. The sleeve bearings shall be horizontally split type.

4.01.20 Duplex type basket strainers shall be provided on the booster pump suction to

protect the fine clearances of the pump. The screening area of the strainer shall be 4-5 times the cross-sectional area of the inlet pipe.

4.01.21 All the design parameters are to be met during under frequency conditions of

47.5 Hz at grid. 4.01.22 The flow impulse for the purpose of recirculation control shall be initiated from

flow measuring device installed at the pump suction. Balancing chamber leak-off shall be piped back to the suction of the respective pump or deaerator.

4.01.23 The Boiler Feed Pump set shall be capable of continuous safe, and trouble free

operation under other than normal condition, like under and over frequency (47.5 to 51.5 Hz), abnormal pressure decay in deaerator, VWO with 1% make-up, over pressure of TG (if envisaged), H.P. heaters out of service, sudden load throw-off, start-up of unit, HP-LP bypass operation, rapid starting and load changes during cyclic two shift and peaking operation.

The successful bidder shall furnish necessary details and calculations

establishing the suitability of the proposed pumps for meeting the above requirements.

4.01.24 The Boiler Feed Pump drives shall be able to accelerate the pumps from

normal standby condition to rated pumping condition in less than 15 seconds after receipt of starting signal. It shall be possible to run the pumps singly as well as in parallel with other pumps.


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4.01.25 The boiler feed pumps shall be capable of coasting down safely to standstill

after it is tripped in the event of a sudden interruption of suction flow. The Bidder shall demonstrate this capability by a suitable dry-running test at his works and shall furnish full details of this proposed test including its duration etc. in his bid.

The dry running test shall not be less severe than closing of the isolation valve

on the feed pump suction and tripping the pump simultaneously. In this condition the pump shall be capable of coasting down safely to standstill without any damage and shall be capable of being in normal service. He shall also describe in his bid any special features incorporated in his design to withstand such dry-running operation.

The feed pump shall be capable of a full dry running condition. The feed pumps

shall have following capabilities: a) The feed pumps shall be capable of accepting complete loss of water

due to incidents such as inadvertent complete closure of suction valve. In such an event, the pump must be capable of being shutdown in a controlled manner and brought down to rest safely after being tripped from normal running condition (design condition) with simultaneous closure of suction valve.

b) The feed pumps shall be capable of accepting without damage transient

reduction in suction pressure well below those required for freedom from cavitation and shall accept without distress, the reestablishment of normal suction conditions following the transient, with no necessity for a pump shut down.

To establish above criterion, the Bidder shall necessarily submit the full backup

calculation, rotor response characteristics, various internal clearances and other features, test reports for similar pumps meeting the above design condition.

In order to demonstrate the above capabilities at shop, the Bidder shall furnish

complete testing procedure along with the bid. The maximum continuous motor rating corresponding to maximum cooling

water temperature of 39oC at cooler inlet shall not be less than the maximum load demand of the driven equipment in its entire range of operation of turbo generator when operating at frequency variations from 47.5 Hz to 51.5 Hz. However, motor shall not be overloaded during any mode of operation of the driven equipment.

The pumps shall be capable of operation over the entire range of NPSH

conditions required without noticeable noise, vibration or damage due to cavitation.

Bidder must ensure that feed pumps operation at flow beyond its maximum flow

handling capability due to low system resistances shall be smooth and without any abnormal noise and vibration and without any necessity of reducing the plant load.


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Bidder shall ensure that no components shall be included with use materials

which are degradable and/or which will need replacement with 40,000 running hours with the exception of mechanical seal face material, which shall be capable of operating for at least 20,000 running hours.

4.01.26 The primary emphasis in the design of the station is on reliability and this shall

be recognised by the contractor in determining pump efficiency. The pumps shall be designed for the highest practicable degree of reliability under all conditions of operation including operation on turning gear and during start-up and transients. They shall also be designed to the extent compatible with the foregoing to minimise restrictions on rapid starting.

4.01.27 The 50% capacity steam turbine driven boiler feed pumps and the drive

turbines shall be identical for ease of maintenance, operation and availability of spares etc

4.01.28 Boiler feed pumps and auxiliaries shall be adequately designed to meet the

60% Turbine HP and LP bypass condition without any problem. 4.01.29 The hydraulic element design should be such that with the special tools

provided the time required for removal and assembly shall be minimum and would provide ease of maintainability.

4.01.30 In no case, the mismatch of feed water through the feed pumps in parallel

operation shall exceed 1% (one) of the average. 4.02.00 Steam Turbine Drive a) Each steam turbine shall be of the condensing, multistage, horizontal

shaft type whose operation will be integrated with the main turbine operation. Each auxiliary steam turbine shall be directly coupled to the shaft of the boiler feed pump on one end and coupled through speed reduction gearbox to the booster pump on the other end.

b) There has to be two independent source of steam supply under normal

and also low load operation. Normally motive steam supply for the auxiliary turbine shall be taken from main steam turbine extraction i.e., IP/LP cylinder cross over pipe. During low load, turbine bypass and shut down operation sufficient extraction steam pressure may not be available to operate the auxiliary turbines. In view of the above, steam from an alternate high pressure source shall be admitted to the turbine through the separate set of control valves, Both sets of steam admission valves (for normal supply and high pressure supply) shall be controlled by the turbine governing system in a coordinated manner, to ensure a smooth change over from one source to another. Cold reheat steam will be the alternate high-pressure source of supply for these turbines.

The Bidder shall furnish all necessary steam admission pipes from

normal source to the auxiliary turbine along with all necessary steam admission/control valves with all instruments and controls as required. Bidder is also to furnish the necessary steam admission pipes from cold reheat line terminal point along with necessary control valves,


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instruments as required for the safe operation of the system. c) Each steam turbine shall be separately ducted to the steam surface

condenser, which serves the main turbine generator unit. The exhaust duct shall be self draining to the condenser.

d) For further detail refer to Vol. –IIE, Section –IV. 4.03.00 Condensate Extraction Pump 4.03.01 Vertical "can" type condensate extraction pumps shall be provided. Its capacity

and TDH shall be calculated based on the guidelines furnished in clause no. 1.02.01 above and also as specified in enclosed Annexure-I.

The bidder shall submit pump-sizing calculations for approval of the Employer. 4.03.02 The pump impellers shall be so designed that wear due to cavitation will not

restrict its service life to less than 40,000 running hours when operating under steady state design suction conditions.

4.03.03 The pumps shall be designed for highest practicable degree of reliability under

all conditions of operation. 4.03.04 The pumps shall have a continuously rising head capacity characteristics from

design point to shut-off. 4.03.05 The condensate extraction pumps shall be suitable (without cavitation) for

handling saturated water, at the maximum possible flow rate from the condenser hot-well, with the NPSH available at hot-well "Low- Low" level.

Suction specific speed for condensate extraction pumps must not exceed 9500

U.S. units. 4.03.06 Pumps shall be capable of operating either single or in parallel. Suitable

Automatic Starting devices shall be provided to bring the standby pump into operation in case of failure of any operating pump.

4.03.07 Rating of the motor shall be selected with at least 10% margin for HT motor &

15% for LT motor over the maximum power required within the range of operation.

4.03.08 The shut-off head of the pump shall not be less than 115% of design head. 4.03.09 The pump rotor assembly (with guides) shall be so designed as to keep its

vibration, in both wet and dry running conditions, within the safe limits as specified in relevant International Standards/Codes. (e.g. ‘Good’ range of VDI 2056 / MIS, USA recommendations).

4.04.00 General The plant is designed for base load service. However, frequent operation will

occur down to 40% load. It is expected that only one condensate pump and one


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boiler feed pump unit will be in service at loads of 60% and lower. 4.05.00 Drive Motors Design and Construction of all drive motors shall confirm to specification for

electrical equipment and accessories as indicated in Volume-IIF of this specification.

5.00.00 BOILER FEED PUMP DESIGN AND CONSTRUCTION 5.01.00 General 5.01.01 The pump shall be of the horizontal centrifugal type supported in such a

manner as to permit free expansion both axially and radially whilst maintaining alignment. The boiler feed pump and suction booster pump will be expected to accept from the main pipe work reasonable forces and moments, the least values being those stipulated in API-610. Therefore, the Bidder shall ensure that all materials and terminal connections are suitable for such terminal forces and moments.

5.01.02 Inter-stage bleed shall be provided in the pump for reheat desuperheating.

Requirement of flow shall be decided by Bidder based on the steam generator demand.

5.02.00 Pump Casing 5.02.01 The casings shall be of suitable design to withstand any possible thermal shock

and/or high pressure and shall be constructed of materials specifically selected to prevent erosion and corrosion.

5.02.02 The barrel type outer casing of the B.F. Pump as well as the booster pump

casing shall be supported at horizontal center line of the pump. The inner casing shall be of axially/radially split type in accordance with the standard proven practice of Manufacturer. The joints shall be constructed in such a way that the feed water discharge pressure acting between outer barrel and inner casing acts to seal the joints. The casing assembly complete with the rotating elements should be located accurately in the outer barrel and it should be possible to remove this assembly without disturbing the suction and discharge piping connections.

The Bidder shall supply a cradle with rollers and necessary attachments for the

removal of the inner assembly. 5.02.03 Pump casings shall be provided with adequate number of vent and priming

connections with valves. Casing drain, as required, shall be provided complete with drain valves. Necessary insulation cleats shall also be provided on the casing.

5.03.00 Rotor 5.03.01 Shaft


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The shaft shall be of tested forgings accurately machined and ground. The material specification and its heat treatment as well as particulars of thermal treatment, proposed to minimise distortion during manufacture, shall be stated in the Bid. Shafts should withstand the stresses set up when the pump will be started quickly. Shaft size should be so selected that full driver output can be easily transmitted without excessive deflection, vibration, distortion or whip.

5.03.02 Impellers The impellers should be accurately machined, finished to close tolerance and

installed individually on the shaft giving special consideration to prevent recirculation between shaft and impeller.

The first stage of inlet impeller should be specially designed to provide most

favourable conditions free from cavitation even during stringent suction condition.

Each impeller shall be balanced individually and the entire rotor assembly

should be statically and dynamically balanced. The rotor shall be so designed that its first critical speed in air or water is above the operating speed. The first critical speed in water shall be at least 130% of maximum speed of the pumps.

Shaft sleeves of hardened wear resisting material shall be provided at all points

of wear. Ferritic wear surfaces shall be preferred. They shall be firmly secured and keyed to the shaft. The material and design shall be such that no internal leakage occurs between shaft and sleeve. The axial thrust of the rotor shall be carried by an approved type of hydraulic balancing device and an external oil lubricated thrust bearing fitted at the outboard end of the pump integral with the journal bearing housing. No axial thrust should be transferred to the electric motor at any condition of operation. The thrust bearing shall be designed for additional load when pump gets vapour bound.

5.04.00 Shaft Seals The main boiler feed pump and the booster pumps shall be provided with fully

cartrigised mechanical seals at the drive and non-drive ends. The mechanical seals shall be of proven design. The seals shall incorporate the material composition not inferior to silicon cartridge/carbon. The seals shall be designed to withstand full dry run condition of the BFP and the Booster pump. Special design feature to withstand such an application should be clearly brought out in the bid. The seals should be designed to have a minimum life of not less than 25,000 hours between overhauls.

The seals should have their own supporting system with 2 x 100 % magnetic

filters, 2 x 100 % tubular coolers, necessary piping and valves, instrumentation controls and other accessories so as to render the system complete. The sealing faces shall not be inferior to Carbon/ Silicon carbide combination and all the ‘ O’ rings shall be suitable for high temperatures. The seal faces shall preferably be designed for a zero leakage.

5.05.00 Bearings Each pump shall be equipped with forced oil lubricated babbitt lined sleeve


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bearings and tilting pad, double acting 100% thrust bearing. The sleeve bearings shall be horizontally split type. The thrust bearing shall be of sufficient size to carry the maximum unbalanced load in either direction due to any emergency operating conditions like the non-operation of the balancing device etc.

Thrust bearing shall be suitable for reverse rotation of pump. Temperature

sensing elements shall be provided for bearing metal temperature indication and thermometers with alarm contacts shall be provided for bearing oil drain.

5.06.00 Lubrication 5.06.01 Each pump set shall be provided with a complete pressure lubrication system of

sufficient capacity for both pump and drive motor, consisting of oil pump, sump tank, water cooled oil coolers (2 x 100%), duplex oil filter, level indicator, sight flow indicator, thermometers, relief valves, pressure regulators and necessary valves, all interconnected piping and accessories. The oil cooler tubes shall be of stainless steel SS-304. The coolers shall be designed for service with demineralized water. The oil pump shall be driven by the feed

pump shaft and all parts of the system shall be mounted as an integral part of

the feed pump assembly. Provision must be made to ensure continuity of oil supply even during reverse rotation of feed pump, and during low frequency operation of oil pumps.

5.06.02 In addition, a standby electric motor driven lubricating oil pump shall be

furnished including the motor drive and pressure switch. This pump will come into operation automatically whenever the normal lubricating system pressure drops below a predetermined setting.

5.06.03 The oil system shall cover the entire lubrication of the pump, motor, step up

gears, the booster pump as also the supply of oil to the hydraulic coupling. Arrangement for proper distribution shall be made using needle valves and orifice plates.

5.06.04 Required electrical interlock shall be provided for continuous, safe and

trouble-free operation of the lubricating oil system, including supply pressure switches for automatic standby pump start, trip and alarm interlocks.

5.06.05 Provisions of pressure lubrication, if necessary, at the time of coasting down of

the feed pump and drive in case of A.C. power failure, shall be arranged by the Bidder.

5.06.06 For auxiliary turbine driven pump sets, the pump lubricating oil shall be supplied

from and returned to the auxiliary turbine lubricating system. 5.07.00 Base Plate The base plate for each pump shall be of rugged fabricated steel construction

reinforced with heavy ribbing. The common base plate shall also accommodate the drive motor, the booster pump, the fluid coupling and the step up gear box


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as necessary. Adequate arrangement to collect leakage oil and leakage water separately and draining up to area drains of plant with piping, isolating valves, funnels etc. shall be provided.

5.08.00 Suction and Discharge Nozzle Heavy reinforced suction and discharge nozzles shall be located vertically

upward on the centre line of the B.F. pump casing. The suction & discharge nozzle shall have approved welding ends. The construction of suction and discharge nozzle must assure maximum strength and reliability and eliminate possibility of leakage at the joints at any operating condition.

5.09.00 Coupling Adequately sized spacer type, extension type or other approved type flexible

couplings shall be used between the pumps, the fluid drive, the step up gear, and the motor drive. Couplings shall have adequate permanent lubrication arrangement and shall be provided with safety guards.

The couplings for turbine driven pumps shall be quick disconnect type suitable

for remote manually disconnecting of the pumps from the turbine. Bidder may submit alternate offer with flexible metal diaphragm type coupling in case, he does not recommend the use of quick disconnect type coupling for offered pump set.

5.10.00 Axial Thrust Balancing Device (Hydraulic) 5.10.01 A suitable device for hydraulic thrust balancing shall be supplied. The balancing

drum shall be designed to balance pump axial thrust. Drum designs shall be relatively long so as to reduce the pressure per linear unit and thus the rate of wear. This should be optimised with the pump shaft span.

5.10.02 Combination of disc and drum or any other suitable modifications may be used

if proven by satisfactorily long experience, and in every case the Bidder shall furnish in his bid the complete details of the system provided.

5.10.03 It is proposed to lead the balancing chamber leak off back to the respective

boiler feed suction line. A flow measuring arrangement shall be provided in the balancing leak off line to monitor the condition of wear in balancing device. All necessary local instruments including leak off flow indicator with alarm contact, valves and fittings required for safe operation of this system shall be supplied by the Bidder.

5.11.00 Material of Construction 5.11.01 Each pump shall be constructed preferably with the following listed materials.

The Bidder shall offer equivalent or better materials with suitable heat treatment as per the standard of the manufacturer for similar duty.

Part Material a) Base Plate Structural Steel


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b) Casing Forged Steel c) Shaft ASTM-A-276, Type 410 d) Impeller ASTM-A-296, Grade CA-6NM e) Diffusers ASTM-A-296, Grade CA-6NM f) Wearing ring ASTM-A-276, Type 420 g) Balancing drum ASTM-A-276, Type 420 h) Balancing head ASTM-A-276, Type 420 i) Shaft Sleeves ASTM-A-176, Type 410 j) Bearings i) Radial Sleeve type (Babbit metal) ii) Thrust Tilting pad, double acting, 100% thrust bearing (suitable material) k) Pressure bolting Chrome-molybdenum steel Between rubbing faces a minimum difference in hardness of 50 BHN may be

maintained. 5.12.00 Non-return Valve 5.12.01 A non-return valve of approved design and manufacture shall be fitted on the

discharge pipe line from each feed pump. The following requirements shall be satisfied.

5.12.02 The closing time of the valve, from the fully opened position, shall not be

greater than the time taken for the pump to stop feeding after being tripped. This shall be of the order of one second.

5.12.03 The valve shall be of adequate pressure rating, alloy cast (or forged) steel

body, 12-14% chrome stainless steel stellited trim, welding end joint, non-slam type.

5.12.04 Where internal components, other than valve seats, are of welded construction,

full penetration butt welds shall be used. 5.13.00 Low Load Protection : Recirculation System 5.13.01 A minimum flow recirculation arrangement shall be provided along with each

pump. Capacity of the recirculation devices shall be so selected that under closed

condition of the B.F.P discharge valve, the temperature rise within the pump


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remain within allowable limits and the internal recirculation at the pump suction impeller eye does not give rise to cavitation.

5.13.02 Bidder shall offer modulating type recirculation control valve. The impulse for

the control valve shall be from the flow-measuring device installed at the boiler feed pump suction.

5.13.03 The valve shall be of reputed make and of design proven in similar application

for three (3) years. 5.13.04 For reducing the bypass pressure to a value suitable for returning to the

deaerator, each pump shall be provided with suitable multiple stellited orifice plates of 11-13% chrome steel with companion flanges for installation in the recirculation piping and adequately designed for prolonged continuous service. Each recirculation line shall be routed independently to deaerator storage tank. An orifice, with a small pressure drop, shall be fitted in each line near the deaerator to prevent any flashing in the pipeline.

5.13.05 The recirculation control valves and all necessary equipment required for

making the system complete shall be furnished by the Bidder for each recirculation control system. All equipment shall be welded end type.

5.13.06 The recirculation control valves shall be designed to open in the event of air or

power failure. Signal lights shall be mounted in the local panel/remote control room to indicate open/closed position of the valve.

5.14.00 Pump Warming Up Device 5.14.01 The boiler feed pump should be designed to start working without any internal

or external warming up arrangement and shall accept hot fluid from deaerator immediately on starting.

5.15.00 High Speed Gear Unit 5.15.01 The gear unit shall be specifically designed for continuous service at the

speeds required by this application. Precision and accuracy of manufacture is essential in order to minimise problems of vibration, impact stress, noise (to attenuate noise level of 85 dB at one meter distance), distortion and lubrication.

5.15.02 Dynamically balanced double helical/epicyclic gears shall be used. The high

speed pinion integral to B.F. Pump shaft and the low speed gear securely keyed to the input shaft should be of approved type of properly heat treated steel according to standard code of practice. The Bidder shall submit detailed specification of the materials used including factor of safety etc. and the detailed description of heat treatment process followed.

5.15.03 Bearings shall be of the split sleeve type, bronze backed with a high-grade

centrifugally cast tin base babbit lining. Bearings shall be adequately sized and accurately machined to assure perfect alignment. Gear journal bearings shall have babbitted thrust faces next to the gear to act as locating surfaces for the gear train.

5.15.04 The gearing shall be enclosed in an oil and dust proof gear case made of close


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grained cast iron or fabricated steel. The gear case shall be horizontally split and stress relieved before machining. Two oil level gauges, drain, fill, vent, temperature switch, thermometer, dipstick, vibration limit switch and other required connections equipped with approved mountings, valves and fittings shall be furnished for the gear casing. The housing shall be of rigid construction to maintain alignment of rotating parts and keep vibration to a minimum. The arrangement shall be such that it will be possible to lift gear case cover without disturbing the alignment of shaft, gear and pinion.

5.15.05 Forced oil lubrication system shall be adopted to lubricate the gearing and

bearings. 5.16.00 Fluid Drive (Hydraulic Coupling for motor driven boiler feed pump only) 5.16.01 The fluid drive shall be a full duty, generously sized, infinitely variable, remotely

controlled, totally enclosed, hydraulic coupling adequately rated to meet the requirement of pump characteristics while operating in the range of capacities specified and required. The speed of the feed pump shall be varied smoothly and stably (automatic control) over the entire range.

5.16.02 It shall be complete with stainless steel impellers, heavy duty roller bearings,

pillow blocks and Kingsbury or Mitchell type thrust bearing for input and output shafts. An enclosing steel housing with removable cover, oil tank, duplex oil filters to remove all particles up to 5 microns, oil temperature and pressure gauges, pumps for oil circulation, stainless steel scoop tube and two full duty integral oil coolers suitable for D.M. Water cooling shall be furnished. The oil cooler shall be adequately rated and shall have arrangement for changing over the cooler without discontinuing the oil flow. Oil cooler tube material shall be Stainless Steel(SS). Necessary water inlet, outlet, drain and vent piping and valves including sight flow glasses in the water outlet shall be furnished.

5.16.03 Full description of the coupling with cross-section and tentative control circuits,

shall be included in the Bid. 5.16.04 The Bidder shall specify the quantity and grade of oil required and mention its

Indian equivalent and furnish speed, torque and efficiency curve for the coupling. The power consumption data for various loads with and without couplings shall be furnished in the Bid for economic evaluation.

5.17.00 Booster Pumps (if applicable) 5.17.01 The booster pump shall be driven directly by the boiler feed pump drive shaft

and shall protect the boiler feed pump from cavitation under all operating conditions. It shall be of single casing, double suction, single stage, horizontally split, self-supported type with adequate number of bearings, designed to carry its load and axial thrust. Shaft sleeve and wearing rings shall be provided at all points of wear.

5.17.02 The material of construction for the booster pumps shall be identical to those

specified for the main pump or better. 5.17.03 Each pump shall be furnished with a flanged suction strainer (the duplex

strainer as already specified for the Boiler Feed Pump) complete with other


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accessories as per requirement. 5.17.04 Necessary pipe connection from booster pump discharge to the suction of the

main boiler feed pump, complete with pipe hangers, flow meters and other necessary instruments, valves etc., shall be included in the supply.

5.17.05 Proper shaft sealing and lubrication system are to be provided to ensure safe

and smooth operation of the pump. 5.18.00 Steam Turbine Drive 5.18.01 General i) Parts subject to temperature changes shall be designed to permit

expansion and contraction without resulting harmful effects. ii) Part subject to wear or requiring adjustment, inspection or repair shall

be accessible and capable of reasonably convenient removal when required.

iii) Thermal stress and distortion shall not be excessive when the auxiliary

steam turbines are subjected to rapid load fluctuation as experienced in normal power station operations.

iv) Each steam turbine shall be furnished as a completely integrated unit

with soleplates insulation material, lubrication systems and other accessories as required for a complete installation.

v) Each steam turbine shall be suitable for full remote operation from the

Owner's control room. 5.18.02 Steam Seals and Drains i) Gland seal steam and seal leak-off systems shall be piped to common

manifolds for connection to main turbine-generator steam seal system. Piping between each auxiliary steam turbine and main turbine shall be in the scope of the Bidder. Steam seal system shall be sized for maximum seal clearances.

ii) The gland steam condenser supplied with the main turbine generator

unit will have sufficient capacity to meet the requirements of the auxiliary steam turbines for the unit.

5.18.03 Lubrication A complete centralized lubrication system for each auxiliary steam turbine-main

boiler feed-booster pump unit assembly shall be provided. The system shall include but not necessarily be limited to the following ;

a) Guarded steel oil pressure piping furnished in areas external to the

reservoir in vicinity of hot turbine parts. b) Main oil pump, AC motor driven, with submerged suction, Provisions for


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local and remote operation of the pump shall be provided. c) Full capacity auxiliary oil pump, ac motor-driven, with sub-merged

suction. Provisions for local and remote manual testing of pump operation and an automatic start (pressure switch), remote manual stop feature shall also be provided.

d) Twin full capacity oil coolers with removable tube bundles for turbine

and boiler feed pump bearing oil, mounted on reservoir or by the side of oil reservoir. Oil cooler tube material shall be Stainless Steel suitable for DM water as cooling medium. Provisions shall be made for either tube bundle to be removed without disturbing turbine operation.

e) Oil reservoir with minimum of five-minute retention time. Contractor shall

provide centrifuge type oil conditioning systems to meet the oil cleanliness of the equipment being furnished. A motor-driven vapour extraction system shall also be provided. Alternatively interconnection with main turbine oil purification system shall be provided.

f) Interconnecting piping between auxiliary steam turbine and oil pumps,

coolers, filters, reservoir, oil conditioning system, as well as other components of the pump set requiring lubrication.

g) Dial-type thermometers to indicate oil temperature to and from coolers,

drain oil temperatures from high pressure and journal, thrust bearing, and low pressure and journal bearing, and other areas as selected by the Bidder.

h) Connection on oil coolers, for oil exit temperature sensor for the Owner's

sensing line for automatic control of the cooling water flow. i) Dial-type pressure gauges to indicate bearing, hydraulic and control oil

pressures, filter inlet and filter outlet oil pressures, and oil pressure at discharge from each of the three oil pumps (main, auxiliary and emergency). Gauges shall be fully connected and provided with shut-off valves. other locations shall be included by the Contractor, if required.

j) Emergency bearing oil pump, DC motor-driven, submerged suction

type, to provide bearing oil pressure only. Including dc motor starter, an automatic start (pressure switch) and remote manual stop feature and provisions for local and remote manual testing.

k) Hand-adjustable, oil pressure reducing valves for auxiliary steam turbine

and boiler feed-booster pump unit lubrication systems. l) Dual-element full capacity oil filters, cartridge-type, with automatic by

pass. 5.18.04 Governor and Controls a) Each steam turbine speed shall be capable of being controlled either

automatically or manually. Automatic control shall be derived from a signal from the boiler feed-water control system, which shall set turbine


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speed through the speed governor mechanisms of the turbine. Manual speed control shall be provided for both local and remote operation. Remote operation shall be accomplished from the main control room DDCMIS. Manual speed control shall be operable from turbine-gear speed to design rpm.

b) The governing system shall be of the type which provides continuous

corrective action until equilibrium conditions are obtained in response to changes in external signal or speed change resulting from other causes, such as change in energy of the steam available to a auxiliary steam turbine drive during sudden load pickup or rejection on the main turbine generator unit.

c) Provisions shall be made in the speed governing system to lock the

auxiliary steam turbine speed to the value existing at the time of any signal failure, and to permit manual speed control thereafter through the speed changer motor. Signal failure shall include loss of signal caused by failure of the signaling device as well as loss of signal caused by loss of power to the signal device. A visual and audible alarm shall be provided both in the Owner's control room, and locally, to indicate loss of control signal.

d) Governor sensitivity shall be responsive to a relatively flat pump head

Vs. flow characteristic at reduced speeds, to provide stable (non-hunting) feed-water flow.

e) Governor shall be electro hydraulic type. f) Control valves shall be provided with devices, which allow for the

installation of both local and remotely operated position indicators covering the full range between open and closed.

g) A turbine-mounted local panel shall be provided with all instruments

required for monitoring of the turbine. 5.18.05 Protective Devices Protective devices provided with each steam turbine shall include but not

necessarily be limited to the following : a) Bolt type overspeed governor set to trip at approximately 10 percent

above maximum rated speed. Overspeed governor shall be independent of speed governor and shall include means for intentional tripping at speeds lower than maximum rated. The test trip shall be locally operated. trip shall include the stop and the control valves. The overspeed test lockout device shall not nullify other protective systems.

b) Hydraulically operated stop valves with weld end. The valves shall be

provided with an oil-operated trip, provision for local and remote testing of the valve while the turbine is in operation, and four (4) limit switches to indicate valve open and closed position. Stop valve control shall be arranged to prevent its opening unless the control valves are closed.


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c) Permanent stainless steel steam strainer with the steam stop valve and a temporary fine-mesh screen start-up strainer. Strainer shall be capable of removal without disturbing steam piping.

d) Remotely-operated solenoid trip arranged to 'energize to trip', including

an interlock to de-energize solenoid after stop valve has closed. e) Remotely-operated solenoid trip reset devices, including an electro-

hydraulic device arranged to reset tripping devices of control and to valves when energized, and interlocks to prevent reset until system oil pressure is established, and to open reset circuit after stop valves when energized, and interlocks to prevent reset until system oil pressure is established, and to open reset circuit after stop valves has been reset. Actuation of reset devices shall not interfere with emergency trip.

f) Thrust bearing wear device to alarm remotely. A test feature for the

device itself, shall also be provided. Additional contact for turbine trip, if recommended.

g) Local manual trip and reset levers. h) Four (4) pressure switches in the oil line for the following purposes : i) Turbine bearing low oil pressure trip with auto-start of D.C. oil

pump and alarm (2 contacts). ii) Turbine bearing low oil pressure alarm and auto-start for

auxiliary oil pump (2 contacts). iii) To be used for station inter-lock purposes. iv) Permissive for turning gear operation. i) Exhaust high temperature alarm with additional contacts for Owner's

Data Acquisition System. j) Exhaust relief diaphragm and rupture disc. 5.18.06 Turning Gear Motor / hydraulic turning gear with automatic engagement/disengagement

facility, shall be provided including interlock which prevents starting of the turning gear until proper turbine oil pressure has been established. In addition, a suitable quick disconnect coupling between the turbine and the pump, with a shifting mechanism for its operation, shall also be furnished.

Bidder shall clearly indicate whether the drive turbine shall have to be initially

put on turning-gear during its start-up for its proper operation. Turning gear equipment furnished shall automatically engage when auxiliary

steam turbine speed falls below a predetermined value. A contact closure for remote indication of turning gear zero speed shall be furnished. The turning gear operation shall be carefully coordinated with the design of the boiler-feed


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pumps to ensure high reliability. 5.18.07 Supervisory Instruments Please refer to Volume-IIE of this technical specification. 5.18.08 Miscellaneous i) Complete insulation and lagging for the auxiliary turbine, steam

admission and exhaust pipes and gland seal piping shall be provided by the Bidder. Permanent metal covering heat insulation shall be provided. Proper thickness and combination of materials shall be based on OSHA practices for acceptable surface temperature for personnel safety.

ii) Sole plates shall be provided by the Bidder for the turbine. iii) Steam blowdown fixtures shall be provided on the stop valves. iv) The Bidder shall furnish one complete unused set of all special tools

required for adjustment and maintenance of the equipment, including lifting slings for the rotor and upper half casing. Tools shall be despatched in a container, which is suitable for permanent storage of the tools.

v) Each auxiliary steam turbine shall be provided with dismantling

equipment, including necessary lifting eyes, jackscrews, etc. 5.18.09 Material of Construction i) Rotor : Solid steel forging ii) Buckets : Chrome alloy with erosion resistance. 5.19.00 Steam Turbine Exhaust Ducts and Metal Expansion Joints 5.19.01 The Bidder shall furnish necessary exhaust duct between the turbine exhaust

nozzle and the steam surface condenser for the turbine generator unit. The exhaust duct shall be complete with transition pieces, drain connection, relief device to open in event of vacuum failure, 500 mm. square manhole, turning vanes to minimise turbulence and friction losses in the ducts and other fittings as required for safe and smooth operation of the plant.

5.19.02 The Bidder shall also furnish metal expansion joints to be installed in the

auxiliary turbine exhaust ducts to the condenser to reduce the forces and moments at the connected equipment due to thermal expansion.

5.19.03 Hangers, supports and auxiliary steel required for supports of ducts and

expansion joints along with the provision of welded attachments on the exhaust ducts are also to be supplied by the Bidder.

5.19.04 The exhaust ducts and expansion joint assembly shall operate safely, properly

and continuously under any combination of pressure and temperature


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conditions m and movements within the system operating limits. 5.19.05 Exhaust Ducts a) The exhaust ducts shall be fabricated and delivered in the largest

sections practicable for field assembly and erection by other agency. b) All mitered exhaust ducts shall be shop welded by the Bidder. c) Round exhaust ducts shall be fabricated in accordance with ASTM A-

155 Grade KC-60, Class-2 or approved equal. d) Rectangular ducts shall be fabricated from A-515 plate or equivalent

using external stiffening as required. e) The exhaust ducts shall be externally ring reinforced to with stand its

service conditions and shall be externally reinforced at locations of support. All welds connecting the stiffening rings to the exhaust dust shall be continuous.

f) Exhaust ducts shall be designed, fabricated, inspected and tested in

accordance with ANSI Standard code for Pressure Piping ANSI B 31.1. as applicable.

g) All welding procedures and weld performance qualifications shall

conform to the requirements of the ASME Boiler and Pressure Vessel Code, Section-IX.

5.19.06 Expansion Joints a) Type Corrugated metal bellows, pressure, hydraulically or roll formed

equalizing or non-equalizing required by the application. Bellows shall be provided with sleeves and cover.

b) Design Cycle life Minimum of 14,000 complete thermal cycles. c) Bellows Shall be formed from singly ply, 300 series stainless steel and shall

contain no circumferential welds. All bellow elements shall be pickled. Annealed bellows shall be passivated.

d) Sleeves The expansion joint shall be furnished with internal sleeves of the same

material as the bellows. The sleeves shall be welded on the inlet end of the expansion joint. All below sections shall be externally sleeved shall have an arrow indicating the direction of flow marked on the outside of the expansion joint.


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e) Covers External removable cover of carbon steel shall be provided to protect

the bellows from physical damage and suitable for supporting thermal insulation.

f) Tie Bars Joints shall be provided with suitable temporary tie-bars to prevent

damage in transit and misalignment during erection. Permanent tie-bars as required shall be furnished by the Bidder.

g) Shop welding procedures and weld performance qualifications shall

conform to Section-IX of the ASME Boiler Code. h) All welds to stainless steel shall be dye penetrant checked.

i) Expansion Joints shall conform to ANSI B 31.1 and to the 'Standards of Expansion Joint Manufacturer's Association'.

j) The expansion joint shall preferably be pressure balanced type, so that

the high force/moment due to the external atmosphere pressure and inside vacuum condition, coming on the duct, can be avoided.

5.19.07 Ductwork Supports i) The design of the ductwork supporting system shall ensure that the

ductwork will be adequately supported, restrained or anchored under all conditions of testing and operation, which can reasonably be expected during operation of a power plant.

ii) The ductwork supports, restraints and supporting steel shall be

designed and constructed in such a manner as to ensure that neither the material used nor the ductwork is over-stressed during any testing or operating conditions.

iii) Ductworks supports other than restraints shall allow free expansion and

contraction of the ductwork and prevent excessive stress from transferred weight being induced into the ductwork or connected equipment.

iv) Restraints shall be designed to permit free ductwork movement in the

direction of the design restraint. v) Constant load supports shall be used adjacent to equipment and where

the vertical differential movement exceeds 20 mm. vi) Variable spring supports may be used where the range of vertical

movement is less than 20 mm. and shall carry the design load in the hot condition.

vii) Restraints shall be designed so that the axis of restraint is parallel to the


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direction of the expected reactionary force when the ductwork is in hot condition.

5.20.00 Butterfly Valves for Turbine Exhaust Ducts 5.20.01 The Bidder shall furnish butterfly valve complete with manual operators for each

exhaust duct to the condenser for the purpose of isolating the turbine (for boiler feed pump) from the condenser.

5.20.02 Shop welding procedures and weld performance qualifications shall conform to

Section-IX of the ASME Boiler Code. 5.20.03 Valves a) Body & Disc : Fabricated steel, ASTM A516, Gr. 60. b) Seats : Nodal elastomer (65 Shore Adurometer per

ASTM D2240-60T) or equivalent against type 304 stainless steel, 360?, suitable for design temperature and pressure. Seat shall be adjustable and replaceable with valve in line.

c) Shaft : Two piece design, made of type 304 stainless

steel d) Bearings : Manufacturer's standard, self lubricated. e) Thrust Bearing : Manufacturer's standard, self lubricated. f) Shaft seal : Water real design suitable for vacuum service. g) Ends : Butt-weld. 5.20.04 Valve operator shall be designed in accordance with Section-12 of AWWA C

504 - 70 and shall have a position indicator, externally adjustable limit stops and a handwheel locking device.

6.00.00 CONDENSATE EXTRACTION PUMP DESIGN AND CONSTRUCTION 6.01.00 The pump unit shall be of vertical can type design. The unit shall consist of a

vertical centrifugal pump submerged in an airtight outer barrel with a pump base plate flange, above which shall be suction and discharge nozzles, a motor mounting stand and a motor coupled to the pump.

6.02.00 The first stage impeller shall be specifically designed for low NPSH requirement

and minimum risk of cavitation. The shaft coupling shall be of flexible type in case the thrust bearing is provided on the pump and it shall be of rigid type if the thrust bearing is provided on the motor.

6.03.00 The condensate extraction pumps shall be of heavy duty power house type


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suitable for long periods of uninterrupted service. These shall be fitted throughout with renewable wearing parts such as wearing rings, shaft sleeves, stage sealing rings etc.

6.04.00 The design and workmanship shall be such that the pumps are readily

assembled or dismantled and that they will operate satisfactorily under all operating conditions without cavitation, pitting, excessive vibration, noise or undue wear.

6.05.00 The glands of the pumps and their associated suction valves shall be suitably

sealed to avoid ingress of air into the condensate under all conditions. The casing vent shall also be complete with all valves, piping, etc., for each pump.

6.06.00 In selecting material of construction of the pumps only proven material for such

services shall be used. The following material of constructions are suggested for guidance only :

Bowl : Cast Iron Impeller for 1st stage : Stainless steel (12% Cr.) Stage impeller : Bronze or chromium steel Shaft : Stainless steel Can : Fabricated steel 6.07.00 The impeller shall be cast in one piece finished all over and carefully balanced

both statically and dynamically. Finally the assembled rotor shall be dynamically balanced and checked for eccentricity.

6.08.00 The condensate extraction pump shaft and can length shall be based on the

pump NPSH required and the condenser hot-well minimum level; the later being determined based on the fluidized condenser size, condenser neck angle of divergence permitted, air system requirement as well as various power cycle system drainage requirement. The pump shaft sizing and bearing location must consider any eventualities in the process of the system design finalisation as above, without any possibility of pump rotor vibration exceeding the specified limit. The Bidder shall furnish the flushing plan for the pump. All necessary piping, fittings and valves are included in Bidder’s scope.

7.00.00 INSTRUMENTATION AND CONTROL Refer to Volume II-E. 8.00.00 INSPECTION AND TESTING 8.01.00 Performance tests are to be conducted to cover the entire range of operation of

the pumps. These shall be carried out in the range from 125% of rated capacity to pump shut-off condition. A minimum five combinations of head and capacity are to be achieved during testing to establish the performance curves, including design capacity points and two extremities of the range of operation specified.


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The tests shall be conducted as per Hydraulic Institute Standard. Performance tests of Condensate Extraction Pumps should preferably be

conducted with actual drive motors. The Bidder shall submit in his proposal the facilities available at his works to

conduct performance testing. If because of limitations on available facilities, a reduced speed test has to be resorted to establish pump performance, the same has to be mentioned in the offer and the applicable performance calculation procedure has to be submitted for approval of Purchaser.

8.02.00 Overall performance test of the Boiler Feed pump shall be conducted in

accordance with ASME P.T.C. 8.2 latest edition or equal to obtain following characteristics. Each pump including the spare rotating assembly (as applicable) shall be tested. At least one of the pumps shall be tested with water at actual working temperature. Tests should be carried out for the following :

a) Total head developed, horsepower requirement and efficiency at the

rated condition. b) NPSH requirement for each rotor at rated speed and temperature, over

the entire operating flow range both for 1% and 3% head drop. NPSH testing shall be governed by ASME P.T.C. and Hydraulic Institute Standards.

c) To establish the pump characteristic curves for head vs. capacity,

power vs. capacity, NPSH vs. capacity and efficiency vs. capacity. 8.03.00 Gear box testing at full load for transmission efficiency and smooth operation.

Noise level to be measured. 8.04.00 Hydraulic coupling speed vs. output and efficiency tests. 8.05.00 Vibration at bearings and noise level shall be checked during performance

tests. 8.06.00 Tests for drive motors shall be as specified in the Standard specification for

A.C. Electric Motors. 8.07.00 Drive turbine shall be tested as per ASME PTC-6 at speed and load conditions

corresponding to the guarantee point and at normal steam conditions. 9.00.00 DRAWINGS, DATA AND INFORMATION REQUIRED 9.01.00 The Bidder shall submit the following with his formal Bid besides the different

information required/asked elsewhere in this specification. 9.01.01 Characteristic curves of pumps showing effective head, pump input power,

efficiency, submergence and NPSH, against capacity ranging from shut-off condition to at least 125% of rated capacity (at several running speeds from minimum to maximum in the case of B.F. Pumps).

9.01.02 Speed Vs. torque curve of the pump corresponding to recommended mode of

pump starting, super-imposed on Speed Vs. torque curve of the motor,


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corresponding to 80%, 90%, 100% rated voltage and also extending from Quadrant-I to Quadrant-II covering reverse flow conditions, if applicable.

9.01.03 Detailed calculations for deriving capacity and head of pumps and sizing of

motors. 9.01.04 Piping drawing for lubrication, sealing, cooling etc. for pumps etc. 9.01.05 Equipment load list and foundation design.

9.01.06 GA Drawings of Turbine Boiler Feed pumps and Motor Driven pumps along

with Booster Pumps and Condensate Extraction Pumps.


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SPECIFIC DESIGN CRITERIA FOR POWER CYCLE PUMPS

SL.NO. ITEM CRITERIA REMARKS

1.00

1.01

1.02

1.03

Boiler Feed Pump Type Number Rating

Horizontal barrel type multistage with suction booster (if applicable). 2 x 50% Capacity turbine driven + 1 x 50% or 2 x 25% or 1 x 30% electric motor driven a) Capacity – (Maximum flow rate through turbine in

VWO condition with 1% make-up) + 10% margin + Design R/H attemperation flow from intermediate stage bleed.

b) Total dynamic head – Rated discharge pressure-323 kg/cm2 (g). (The above data is tentative. Based on finalization of boiler data during detail engineering stage the contractor shall estimate the final TDH after approval from Owner/Consultant).

c) Speed - Variable (stepless).

Heads developed at the interstage bleed and kicker stage discharge shall be adequate for meeting the attemperation requirement of the boiler.


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SL.NO. ITEM CRITERIA REMARKS

2.00

2.01

2.02

Condensate Pump Type Number

Vertical can type centrifugal design. 3 x 50%

2.03

Rating

a) Capacity - Maximum steam flow at exhaust during

VWO (plus 1% make-up) operation of turbine with maximum steam inlet pressure plus all heater drains and vents diverted to Condenser.

The pumps shall also be capable of sustaining emergency transient conditions like H.P. heater(s) out, Turbine H.P. & L.P. bypass in operation etc.

b) Head - Maximum deaerator pressure plus static and dynamic head under maximum capacity condition.

2.04

Margin on Capacity 10% over theoretically calculated rated capacity.

2.05 The Pump Best Efficiency point should be at the rated discharge (design point), the efficiency during 100% TMCR operation shall not fall appreciably (more than 2%) from the best efficiency value.

VOLUME : II-C

SECTION-IV

CONDENSER AND AIR EXTRACTION SYSTEM


CONTENT

CLAUSE NO. DESCRIPTION PAGE NO. 1.00.00 GENERAL INFORMATION V.IIC/S-IV : 1 2.00.00 CODES AND STANDARDS V.IIC/S-IV : 1 3.00.00 EQUIPMENT AND ACCESSORIES TO BE FURNISHED V.IIC/S-IV : 2 4.00.00 GENERAL PERFORMANCE REQUIREMENT V.IIC/S-IV : 3 5.00.00 DESIGN AND CONSTRUCTION V.IIC/S-IV : 4 6.00.00 INSTRUMENTATION AND CONTROL V.IIC/S-IV : 9 7.00.00 INSPECTION AND TESTING V.IIC/S-IV : 9 8.00.00 DRAWINGS, DATA AND INFORMATION REQUIRED V.IIC/S-IV : 10 ATTACHMENT ANNEXURE-I SPECIFIC DESIGN CRITERIA FOR CONDENSER AND AIR EXTRACTION

SYSTEM V.IIC/S-IV : 11


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VOLUME : II-C

SECTION-IV

CONDENSER AND AIR EXTRACTION SYSTEM

1.00.00 GENERAL INFORMATION 1.01.00 Each turbine-generator unit shall be provided with condensing plant/s

consisting of condenser/s, a set of air extraction equipment and accessories as described in this specification.

1.02.00 The condenser shall receive the exhaust steam from the steam turbine. The

condenser shall also receive heater drains and system make up. The condensate formed shall be extracted from the hot well by condensate extraction pumps and pumped to the deaerator through gland steam condenser and L.P. heaters.

1.03.00 The steam inside condenser shall be cooled by water pumped by circulating

water pumps and recirculated through cooling towers. 1.04.00 During start up and other operating conditions, steam will be dumped into the

condenser fully or partly bypassing the steam turbine. The Condenser shall be suitably designed to receive such bypass steam.

1.05.00 The Air extraction equipment to be used for creating the necessary vacuum in

the condenser during starting up of the unit and during normal operation by removing non-condensable vapours and gases, shall be designed suitably to work satisfactorily in conjunction with the condensing unit.

1.06.00 The condenser will be located below the exhaust of the turbine, its axis being

normal to that of the turbine. The air extraction equipment shall be mounted suitably near the condenser.

2.00.00 CODES AND STANDARDS 2.01.00 Nomenclature, definitions, design, materials and construction of the condenser

and air removal equipment furnished under this specification shall comply in all respects with requirements of the latest edition of Heat Exchange Institute (HEI) standards for steam surface condenser. HEI standards or equivalent shall be followed for thermal design and IS-2825/HEI/ASME for strength design of condenser.

2.02.00 PTC 12.2 : ASME Performance test codes for Steam Surface Condensers. Performance test codes shall be of international acceptable standards as applicable including those mentioned below. Standards of the Hydraulic Institute of USA. PTC 8.2 : Power Test Codes - Centrifugal pumps.


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ASME Section VIII: Pressure Vessel Code , 2001 ASTM - American Society for Testing & Materials. American National Standards (ANSI) on – • Steel Pipe Flanges and Flanged Fittings (B 16.5) • Steel Fittings S.W. and Threaded (B 16.11) • Butt welding ends-Pipe, valves, & fittings (B16.25). • Valves – Flanged, Threaded and Welding End (B 16.34) American Society for Non destructive Testing (SNT-TC-1A) NEMA : National Electrical Manufacturer's Association OSHA : Occupational Safety and Health Act IEEE : Institute of Electronics and Electrical Engineers ISA : Instrument Society of America Other standards such as IEC, VDI, DIN, BS, IS etc. shall also be accepted subject to the owner's approval for which the bidder shall furnish along with the bid adequate information to justify that these standards are equivalent or superior to the standards mentioned above. For such alternate standards which are not normally published in English, bidder shall also furnish a complete translation for them. 3.00.00 EQUIPMENT AND ACCESSORIES TO BE FURNISHED 3.01.00 Each condensing and air extraction plant for each unit shall consist of the

following : 3.01.01 One (1) surface condenser with turbine connection and if necessary expansion

joint at condenser neck along with complete condenser supporting arrangement (fixed type or spring mounting type) - including springs, bolts, nuts, pads, mounting plates etc. as necessary. Necessary flash tanks and interconnected piping are also included.

3.01.02 Air-extraction systems shall be as follows :

Two (2) numbers 100% capacity mechanical vacuum pumps of liquid ring design, of which one will operate continuously and both will be operated during start-up to create initial vacuum within 25 minutes time. Supporting air ejector (if required) for abnormal operation with selection of suitable compression ratio for the air ejector.

3.01.03 All air piping, condensate piping, vent piping, steam piping etc. related to air

extraction system. 3.01.04 Pressure balanced Rubber expansion Joints, as required with counter flanges,

control units, rocking washer (Spherical nuts), fastening materials alongwith bolts, nuts & gaskets etc. and Butterfly valves to be located on C.W. piping at condenser water box inlet and outlet.

3.01.05 Sponge rubber ball type condenser tube cleaning system with ball recirculation

pump, strainer, automatic ball sorter etc. as per Section-VII of this volume.


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3.01.06 Condenser hot well level instruments including full length gauge glass with

isolation valves, high/low alarm level switches, connections for level transmitters, temperature gauges etc. and filling up connections, as applicable. Hot well level switch shall be conductivity type.

3.01.07 All necessary nozzle connections on the condenser shell, hot well, water

boxes, air extraction equipments etc. counter flanges complete with bolts, nuts, gaskets etc. for C.W. inlet and outlet connections of the condenser.

3.01.08 All base frames, support plates, anchor/fixing bolts, nuts, gaskets, eye bolts,

lifting lugs, auxiliary steel member for supports, hangers, stiffeners, sleeves etc. and parts embeded in concrete. Attachments to facilitate the opening of front and rear water boxes without dismantling to the extent possible at the CW inlet and outlet piping.

3.01.09 Necessary steel platforms and supports, required for operation of the

equipment. 3.01.10 Valves subjected to below atmospheric operating pressure should have

suitable deep stuffing box such that the same preferably do not require sealing water. However, if the same requires sealing water, the entire gland sealing piping complete with valves, specialties etc. shall have to be provided by the Bidder. Sealing water should be tapped off from any suitable point in condensate line.

4.00.00 GENERAL PERFORMANCE REQUIREMENT 4.01.00 The condenser shall be designed such that steam received from the Turbine

exhaust during turbine VWO operation with 3% make-up, all heaters in service, and auxiliary turbine drive of Boiler Feed Pump engaged, can be condensed along with other heat rejections like all heater drains & vents diverted to the condenser etc. maintaining the condenser pressure of 77 mm of Hg. absolute or lower with cooling water temperature of 33 °C with 5% of tube plugged and having a tube cleanliness factor of 90%. Terminal temperature difference shall not be less than 2.8 °C. The cooling water temperature differential across the condenser shall remain within 10 °C (during maximum thermal load).

4.02.00 The Bidder shall also check and ensure full capability of the turbine for a

condenser pressure of 89 mm mercury absolute. 4.03.00 The condenser and associated equipment shall also be adequately designed to

meet H.P. bypass and corresponding L.P. by pass condition without any problem.

4.04.00 The oxygen content of the condensate leaving the condenser shall not exceed

0.015 c.c. per litre over the entire load range. 4.05.00 The condenser shall be capable of maintaining continuous turbo-generator

operation with at least 60% TMCR load when one half of its water box is isolated for maintenance.


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5.00.00 DESIGN AND CONSTRUCTION 5.01.00 Condenser 5.01.01 Condenser Type and Duty The condenser shall be of two pass, horizontal, surface type with integral air

cooling section. The condenser shall be so designed that it can operate satisfactorily under the different off-normal operating conditions of the turbine such as fully or partly by-passing of the turbine, closing of one or more extraction openings etc. The condenser shall be designed for efficiently deaerating the heat cycle make-up, which will be introduced into the condenser. Sub-cooling of the condensate shall be avoided. The condenser hotwell should have a minimum available volume sufficient to contain between its "normal" and "low" levels the condensate that may be produced in the condenser in a period of three (3) minutes under condition of maximum steam load. Hotwell shall preferably be divided longitudinally with pump suction from both sides.

The condenser shall be arranged for installation with the tubes at right angle to the axis of turbine rotor and shall be designed for a minimum width and for installation below a reinforced cement concrete turbine generator foundation (TG foundation included under the scope of Civil Package). Condenser shall be furnished in two sections. Each water box shall be divided into two halves and the two sections shall be completely isolated from each other with separate inlet and outlet connections so that one half of the condenser can be isolated on the cooling waterside for inspection and maintenance while the other half is in operation. The cooling water inlet connections shall be at the bottom and outlet connection at the top.

The condenser overall dimensions, together with the space required for withdrawal of condenser tubes and dismantling/opening of each water box cover shall be suitable for the T.G. building dimensions and local pipe layout so that no dismantling of any equipment or CW or other piping or breaking of wall/floor is required for condenser tube/water box maintenance or replacement.

Corrosion allowance of minimum 0.8 mm on each welded side for the shell side and 3.2 mm for water boxes and tube plates shall be applied to the design thickness of each component. No corrosion allowance shall be provided on tubes.

C.W. butterfly valves with actuators to be designed as per AWWA-C-504-80 or Owner approved equivalent standards. Valve material shall be suitable for sea water duty.

C.W. expansion joints made from high quality natural / synthetic rubber with

stainless steel reinforcement rings and with flanges as per ANSI-B16.25. The expansion joints shall be designed to the deflections and fluid pressure through out plant life and shall be suitable to withstand full vacuum without collapse and the proposed arrangement for this shall be indicated in the offer.


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Further the design shall limit the reaction forces/moments on condenser CW nozzles and on C.W. piping.

Design, Material and construction of CW piping and butterfly valves shall be as per relevant standards

5.01.02 Condenser Shell and Fittings

The condenser shell shall be carefully shaped in conjunction with the tube arrangement and provided with baffles as necessary to ensure proper distribution of steam over the whole of the tube nest with minimum shock load and to eliminate all areas of excessive steam velocity. Extraction pipes passing through condenser neck shall be provided with stainless steel shroud around each pipe to prevent erosion due to steam. Condenser shell shall be of boiler quality plate to ASTM Specification A516 Gr.70 The design shall be as per ASME pressure vessel code. The condenser shell (steam side) shall be designed from full vacuum to a minimum internal pressure of 1.08 Kg/Sq.cm (g). The shell side design temperature shall be 120 °C. The minimum wall thickness for the shell shall be 16 mm.

Shell shall be designed for a minimum number of site welds. Expansion joints shall be provided in the condenser shell to take care of differential expansion between the shell and tubes.

The condenser shall be adequately supported so that no upward thrust is imposed on the turbine under all conditions of operation. If the design incorporates an expansion piece, it shall preferably be in fully stabilised Austenitic stainless steel all welded type, designed to reduce flow interferences to a minimum. Design of expansion joints shall take care of the set pressure of bursting disc on turbine exhaust and corresponding temperature along with the turbine movements. Means shall be provided to prevent any load being imposed on the turbine casing when the condenser steam space is filled with water during hydrostatic testing of the condenser.

Suitable manhole with hinged covers on the upper part of the shell and hotwell portion shall be provided to facilitate maintenance. Manhole sizes shall be minimum 500/600 mm (for condenser portion only). Necessary connections on the condenser shell and hotwell for air removal, introduction of make-up, individual recirculation and recirculation from main condensate line (to maintain minimum flow through condensate extraction pump), drains, vents & instrumentation shall be provided. In case there are two separate condensers for the two exhausts, the connections shall be duplicated as far as possible so that operation with one section out may be possible. At all points where steam and water enter the condenser shell, baffles of SS:304 shall be provided to prevent direct impingement on the tubes. All bolts, nuts, stays etc. inside the steam space shall be of approved material and where such parts project through the tube plates they shall be fitted with gun metal or approved cap nuts and protective sleeves. Stainless steel spray piping shall be provided to distribute cold make-up water in such a manner as to provide suitable heating and deaeration. The other fittings shall include but not be limited to the following :


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a) Drain valves and one set of water level gauge for each section of the

condenser hotwell as also a complete arrangement for sample collection and conductivity measurement from each section.

b) Nozzles with strainers for connection to extraction pumps from each

section of the hot well. The suction pipe of CE pumps should be laid above ground floor and valves should be easily accessible.

c) Air outlet connections.

d) Steam throw-off device to effect pressure reduction and condensate

spraying on the steam from L. P. bypass station when the turbine is bypassed.

e) All necessary connections for instrument and controls.

f) One isolating valve on the top of the steam space of each condenser

shell or top of each turbine exhaust piece for vacuum gauges. g) Suitable thermometer pockets on each of the cooling water inlet and

outlet branches, at top of the steam space of the condenser shell, in the air suction branch of the shell, in each section of the hotwell and also thermowells on each end of the condenser shell.

h) Flash boxes with manifolds to receive all feed heater drains, and

various other system drains; vent and drain piping from each flash box for connection to the condenser steam space and hotwell.

i) Connection from auxiliary turbine exhaust with suitable baffle. 5.01.03 The condenser tube plates shall be of carbon steel conforming to ASTM

A516Gr. 70. Water side of tube plates shall be cladded with Titanium. The tube plate shall preferably be welded to the shell. . All tubes shall be of tested quality and the Bidder shall submit the test certificate of the cooling tubes. Each tube shall be eddy current tested for soundness.

Condenser tube material shall be welded titanium ASME B-338 Gr.II without any circumferential joint suitable for duty intended. Tube size shall be 22 mm to 25 mm O.D. and min. 22 BWG thick. Top row of tubes shall be extra thick and shall be material Cr Mo steel(29Cr1Mo). The thickness of top rows of tubes in impingement zone as decided by the bidder based on tube layout shall, however, be of Minimum 20 BWG thickness.. Provision for taking care of thermal expansion of tube bundle and proper drainage of tubes during shut down shall be ensured. The tube water velocity shall be within a range suitable for the material selected as recommended by Heat Exchanger Institute (USA). . Tube nest as a whole shall be slightly inclined to provide self-draining of tubes when the condenser is shut down.

A catch trough shall be provided at the bottom of each tube-plate towards the steam side so that any leakage of cooling water through a tube-tube sheet joint


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will first get collected in the catch trough. A SS-304 drain pipe from each catch trough shall be provided penetrating out through the condenser/hot-well shell and having a SS-304 isolating cock at the outlet end for sampling connection/conductivity measurement.

5.01.04 Tube Support Plates

The tube support plates shall be of steel ASTM A516 Gr.70 construction and arranged suitably so that no periodic vibration of tubes may be induced by the running of the Turbo Generator and the maximum span shall be limited such that vibration induced by steam flow may not occur. Tube holes shall be accurately drilled to provide suitable clearances on the diameter of the tube. Edges of the tube holes in the support plates shall be chamfered to facilitate tube insertion and shall be deburred to prevent tube damage.

5.01.05 Water Boxes and Covers

a) The water boxes shall be designed for the shut off head of the cooling water pumps.

b) Water boxes shall be supported from condenser shell by flange

connection. Condenser design and construction shall assure complete support of the fully flooded water boxes from the condenser shell without requiring auxiliary supports.

c) Material of construction for the water boxes and its covers shall be

carbon steel of ASTM A-516, Grade 70, with FRP/GRP lining. d) Water boxes shall be tested with a hydrostatic test pressure as

recommended by Heat Exchange Institute (USA). e) Cathodic protection of water boxes and tube sheets shall be provided.

f) Suitable drain and vent connection with necessary valves shall be

provided for each compartment of the water box.

g) Design shall provide the optimum entrance condition to the tubes. Strengthening ribs shall be suitably provided on outside face only.

h) Access doors and inspection windows shall be provided in each

compartment at minimum two levels to permit easy internal access and inspection.

i) Adequate arrangement shall be made for removal of water box cover

for tube replacement without disturbing C.W. piping. Necessary monorail, hoist block etc. shall be included.

5.02.00 Air Evacuation System - Vacuum Pumps 5.02.01 The condenser air evacuation system shall be suitable for operation in

conjunction with the turbine and condenser offered. Each unit shall comprise of 2 x 100% vacuum pumps with all accessories for condenser air evacuation. These mechanical vacuum pumps shall be sized as per latest HEI requirements. Capacity of each pump shall be sufficient to maintain


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continuously the condenser vacuum corresponding to the saturation pressure of the condensate in hotwell at design cooling water temperature, when the condenser is working at its design capacity of steam, condensate and heat input (VWO steam flow, heater drains diverted to condenser etc.).and also during operation of the unit at lowest TG load for all C.W Temperature.

Besides, the pump capacity shall also be such that at starting, with both pumps working in parallel, it is possible to create within 25 minutes sufficient vacuum in the condenser suitable for raising the steam turbine to its full speed. The design capacity of each pump shall be selected to meet both the above requirements with a margin of 10%. The pump TDH shall take into account the pressure drop, in suction pipeline between pumps and condenser and in the pump discharge side including air vent pipe stack outside Turbine building, as estimated for the design capacity. The sizing calculation of the system shall be furnished with the offer. The pumps should not trip under low system frequency (47.5 Hz) operation.

5.02.02 The pumps shall be single stage/double stage, as necessary to meet the design conditions. The pumps shall not cavitate under all operating conditions.

5.02.03 Suitable compression ratio shall be selected so that the pumps operate

effectively at all conditions of operation with cooling water temperatures mentioned above.

5.02.04 The pumps shall be designed for indoor installation and for continuous duty, to

handle mixture of air, steam and non-condensable gases. Bidder shall ensure and guarantee that pump shall not cavitate at any load, including part loads and design point,

5.02.05 The pumps shall be of liquid ring design with both the stages (in case of two

stage pump) mounted on a common shaft. The unit shall require no internal lubrication and shall be free from damage by water vapour, entrained droplets or slugs of water.

5.02.06 Each unit shall be complete with liquid ring vacuum pump, drive motor, flexible

coupling and coupling guards, water separator with gauge glass and automatic make-up and overflow valves, suction and discharge piping, expansion joints, inlet system valve with differential pressure switches, system vacuum switch to start automatically the standby unit, heat exchanger for seal water cooling, seal water recirculation pumps, air ejector, rotameters for discharge air measurement, vacuum gauge for system inlet pressure, pressure gauge for seal water pressure, temperature gauge for seal water, outlet check valve, relief valves (if required) and other necessary instrumentation, control and wiring. The entire unit shall be mounted on a common steel base frame.

5.02.07 Necessary device shall be incorporated in the design of the equipment so as to

prevent loss of vacuum by flow of atmospheric air back into the condenser upon shut down of the pump.

5.02.08 The heat exchangers shall be arranged to permit access to tubes without

disturbing the piping connections. The heat exchanger tubes shall be of SS-304


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(Seamless/welded). If U-tube heat exchangers are offered, the tube bundle shall be of removable type.

5.02.09 The material of the pumps shall be so chosen as to accept condensate as the

source of sealing water. 5.02.10 The materials of the vacuum pump and seal water recirculation pump shall be

as below or superior : i) Casing : Nickel cast iron ii) Shaft : Carbon steel EN-8 iii) Impeller : Nodular iron/stainless steel iv) Shaft Sleeves : Nodular iron/stainless steel 5.03.00 Nozzle Connections

All necessary nozzle connections for the system as required by the Turbine-Generator manufacturer and the heat cycle system shall be provided. All water (make-up water, exhaust hood spray, condensate recirculation etc.) to the condenser shall be fed through perforated pipes suitably located. The supply shall include necessary internal piping with spray holes. In regions where impingement is likely to occur, the tubes shall be protected by stainless steel baffles & extraction pipes shall be protected by stainless steel shields.

5.04.00 Condenser Tube Cleaning System

A continuously operating sponge rubber ball type on load condenser tube cleaning system, consisting of ball recirculation pumps with drive motors, ball collectors & regulators, automatic ball sorter, ball collecting strainer, debris filter, piping, valves, nozzles, instrumentation and control shall be provided with each condenser unit to remove fouling materials from condenser tubes.

6.00.00 INSTRUMENTATION AND CONTROL

Refer Volume : II-E. 7.00.00 INSPECTION AND TESTING 7.01.00 The water box and shell shall be hydrostatically tested as per Heat Exchange

Institute Standards. During hydrotest the gasket tightness shall be to measured extent. Gaskets shall be replaced by new ones after shop test.

All condenser tubes shall be hydraulically tested to 70 Kg/Sq.cm.(g) internal pressure & also inspected ultrasonically or by eddy current testing as per ASTM E213-68 and ASTM E243-67T respectively prior to shipment.

7.02.00 The completely assembled and tubed condenser shall be hydrostatically tested

after erection, according to the standards of Heat Exchange Institute.


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7.03.00 Condenser shell shall be tested for any leakage by filling the steam space with water.

7.04.00 A field performance test shall be conducted in conjunction with approved

Acceptance Tests Procedure. 7.05.00 Performance of the air removing equipment shall be tested at the

manufacturer's shop according to the applicable ASME Performance Test Code, PTC 24 - "Ejectors and Boosters".

8.00.00 DRAWINGS, DATA AND INFORMATION REQUIRED 8.01.00 Characteristic curves for condenser performance showing condenser pressure

for heat load range of 30 percent to 120 percent of the design heat load with varying circulating water temperatures (15 °C, 20 °C, 25 °C, 30 °C, 33°C, 36 °C) for tube cleanliness factor of 100% and 90%.

8.02.00 Performance curve for the air ejectors/vacuum pumps showing :

a) Suction pressure against dry air capacity (N.Cu.m/Min)

b) Suction pressure against cooling condensate flow.

c) G.A drawing of condenser, Vacuum pumps and Ejectors 8.03.00 Equipment load list and foundation design.


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SPECIFIC DESIGN CRITERIA FOR CONDENSER

AND AIR EXTRACTION SYSTEM

SL.NO. ITEM CRITERIA REMARKS 1.00.00 CONDENSER 1.01.00 Type Two pass, water cooled. Spring mounted. 1.02.00 Design Standard As per HEI, USA for

thermal rating and IS-2825/ASME for strength.

1.03.00 Tube material Welded Titanium B-338 Gr II. and Tube plate ASTM A 516 Gr 70 1.04.00 Thermal load i) Turbine Exhaust flow during Turbine VWO operation with all drains and vents from feed Water Heaters led to Condenser along with boiler feed pump’s auxiliary turbine exhaust. ii) Maximum flow under

HP-LP Bypass condition with house load operation without tripping the turbine at low vacuum condition.

1.05.00 Cleanliness Condition 90% 1.06.00 Tube Plugging margin 10% 1.07.00 Design Cooling Water 33 °C temperature 1.08.00 Water box design pressure 5 kg/sq.cm (g)

Steam side design pressure Full vacuum to 1.08 kg/cm2(a)



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SL.NO. ITEM CRITERIA REMARKS 1.09.00 Design Condenser 77 mm Hg abs. vacuum 1.10.00 Hotwell storage capacity Minimum 3 minutes

(between "normal" and "low" level) with maximum steam condensed.

1.11.00 Velocity of water in 2.2 m/sec (Maximum). tubes 1.12.00 Cooling Water Tempe- Not more than 10 °C

rature differential (during maximum thermal across condenser load).

1.13.00 TTD Not less than 2.8°C 1.14.00 Oxygen content in the condensate leaving hot well < 0.015 cc/litre 1.15.00 Allowable circulating water friction loss through clean tubes 4MLC and water box 1,16.00 Tube sheet, water box parting plane and other surface in condenser To be with coming in contact with FRP/GRP lining sea water



DCPL-11Z02

SL.NO. ITEM CRITERIA REMARKS 2.00.00 AIR EXTRACTION SYSTEM 2.01.00 Type Vacuum pump air evacuation system 2.02.00 Number 2 x 100% mechanical

vacuum pumps with all accessories. During start-up both the pumps may operate simultaneously.

2.03.00 Capacity As per HEI, USA or

equivalent code of International repute.

3.00.00 RUBBER EXPANSION JOINT: 3.01.00 Nos At inlet and outlet of

C.W.Nozzle 3.02.00 Material Neoprene rubber. 3.03.00 Shore hardness 65±5˚ 3.04.00 Control unit etc. Galvanized steel

VOLUME : II-C

SECTION-V

TURBINE OIL PURIFICATION SYSTEM


CONTENT CLAUSE NO. DESCRIPTION PAGE NO. 1.00.00 GENERAL INFORMATION V.IIC/S-V : 1 2.00.00 EQUIPMENT AND ACCESSORIES TO BE FURNISHED V.IIC/S-V : 1 3.00.00 PERFORMANCE REQUIREMENT V.IIC/S-V : 2 4.00.00 DESIGN AND CONSTRUCTION V.IIC/S-V : 2 5.00.00 INSTRUMENTATION AND CONTROL V.IIC/S-V : 4 6.00.00 INSPECTION AND TESTING V.IIC/S-V : 4 7.00.00 DATA, DRAWINGS AND INFORMATION REQUIRED V.IIC/S-V : 4 ATTACHMENT ANNEXURE-I SPECIFIC DESIGN CRITERIA FOR TURBINE LUB OIL PURIFICATION SYSTEM V.IIC/S-V : 5


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VOLUME : II-C

SECTION-V

TURBINE OIL PURIFICATION SYSTEM

1.00.00 GENERAL INFORMATION 1.01.00 Each turbo-generator units shall consist of a lube oil/governing oil system

circulating through pumps, piping and a unit turbine oil tank. Each of these units shall have its own oil purification system. Besides, there shall be a centralised turbine oil receiving and transfer station, common for both units, consisting of dirty oil & clean oil tanks, oil receiving & transfer pumps, oil purification unit, piping etc.

1.02.00 Three (3) nos. turbine oil purification units of equal capacity shall be required

for the above-mentioned systems. One each shall clean the oil drained from each of the two unit turbine oil tanks and the third for the central station.

1.03.00 Purification system for each of the two (2) turbo-generator units shall operate

continuously as a bypass system. 2.00.00 EQUIPMENT AND ACCESSORIES TO BE FURNISHED 2.01.00 The Unit Turbine Oil Purification systems consisting of two purification units,

each with oil centrifuge, antiflood tank, feed pump, discharge pump, indirect oil heater and related accessories.

2.01.01 Unit turbine oil tank with drain piping through level indicating type seal box. 2.01.02 Central lube oil storage, purification and transfer system is common for both the units , the system consists of the following equipments

i) One clean oil transfer pump ii) One dirty oil transfer pump iii) One central lube oil purifier

vi) One oil unloading vessel. 2.01.03 One (1) polishing filter for each lubricating oil purification system. 2.01.04 Two(2) central storage tanks, one for clean oil and one for dirty oil, each complete with level indicators, necessary oil inlet , outlet, drain and vent connection, floating suction etc. as required. 2.01.05 2 x 100% Oil transfer pumps for transferring dirty oil from the unit oil tank to the

Dirty Turbine Oil Storage and Purification System or of clean oil from Dirty Turbine Oil Storage and Purification System to the unit oil tank, with piping, valves and accessories.


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2.01.06 An AC motor driven centrifugal type portable lube oil purifier shall be provided for the water and particle/ sludge removal from lubricating oils, other than STG lube oil , like fans, BFP etc., which has its own separate purifier. It shall be designed to purify the various lubricating oils used. 2.01.07 Interconnecting piping between the purifying units and turbine oil tanks 2.02.00 Necessary piping, valves, strainers, flow meters, gauges, hangers, supports,

controls, instrumentation etc. required for the systems. 2.03.00 All electrical accessories, wiring, starters, switches etc. including one control

panel complete with annunciation system. 2.04.00 All base plate, foundation bolts, sleeves etc. 3.00.00 PERFORMANCE REQUIREMENT 3.01.00 Each purification system shall have a flow capacity per hour of 20% of the total

oil in the unit oil system (i.e. the total quantity of oil required to fill the oil system of one turbo- generator unit) or 6000 litres per hour whichever is higher.

3.02.00 The capacity of each compartment of central storage tank or one central

storage tank shall be sufficient to hold total oil in the unit oil system or 30 m3 whichever is higher.

3.03.00 The oil at the outlet of the polishing filter shall not contain any free moisture &

particles of size higher than two (2) microns. 3.04.00 Oil at the outlet of centrifuge shall not contain free moisture and particles of

size higher than five (5) microns when the oil is heated to a temperature of not more than 65°C.

3.05.00 The equipment shall be suitable for continuous operation round the clock.

Normally one scheduled overhaul per year should be sufficient. 3.06.00 The capacity of Dirty and Clean oil tank shall be atleast 150% of one unit oil

requirement. 4.00.00 DESIGN AND CONSTRUCTION 4.01.00 Centrifuge Purifier 4.01.01 The centrifuge shall be complete with drive motor and transmission shall be

through gears or alternatively through belt and pulley. 4.01.02 The centrifuge shall be equipped with suitable anti-seal loss device to prevent

loss of oil with heavy phase drain beyond the limit guaranteed by the supplier. 4.01.03 The material for the rotating parts of the centrifuge shall be high grade

stainless steel AISI-316 or equivalent. Other parts in contact with the oil shall be of stainless steel or of other corrosion resistant material conforming to IS,


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ASTM or equivalent standard. The casing shall be of cast iron or carbon steel construction. The construction shall be vapour tight.

4.01.04 The arrangement of the assembly must enable easy removal of the collected

solid particles within a short time. The centrifuge shall be equipped with sight glasses both for the purified oil and the separated water from collecting pan.

4.01.05 The mounting arrangement of rotating parts must be designed to eliminate

undue imbalance and vibration. The rotating parts shall be statically & dynamically balanced.

4.01.06 Necessary annunciation, interlock and safety devices shall be provided for

safe and trouble-free operation in local panel. 4.01.07 It should also be possible to use it as a clarifier. 4.02.00 Electric Heater 4.02.01 Oil shall be heated to a suitable temperature not more than 65°C by electric

heater. 4.02.02 Two (2) sets of heater elements each 100% capacity complete with

associated fuse, starter, control switch and thermostat with indicator shall be provided. Each heater element shall be designed for preheating the oil to the temperature required for proper centrifuging at the rated purifier capacity. Each set of heater element shall preferably be divided into two groups for controlling in two steps, 50% and 100% of total KW rating. The heater elements shall be easily removable. The heater circuit shall be interlocked with pump motor circuits to shut off the heaters when the pumps are not being operated.

4.02.03 The heater shall be complete with oil inlet, oil outlet, drain, vent, overflow and

other connections as necessary with interconnecting and bypass piping, valves etc. Suitable level gauge glass, inlet and outlet thermometers and pressure gauges, and float switch shall be provided.

4.03.00 Oil Pumps 4.03.01 The pumps shall be horizontal, rotary positive displacement type. The pumps

shall be of the helical, herringbone, spur gear or screw type. The pumps shall have built-in or externally mounted adjustable type relief valve for protection.

4.03.02 The pumps shall be complete with drive motor. The pumps shall preferably be

directly driven through flexible coupling. A common drive will be preferred for a set of clean and dirty oil pumps.

4.03.03 The unit turbine oil tank and the purification unit should have adequate

capacity to receive maximum oil contained in the entire oil system. 4.03.04 The design of the pumps shall be as per standards of "Hydraulic Institute of

USA" or approved equivalent. The materials for various components shall be as recommended in the standard. The casing and base plate shall be of cast


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iron construction, the rotor and shaft shall be of carbon steel. High tensile steel bolts and nuts shall be used for the casing.

4.04.00 Polishing Filter 4.04.01 The polishing filter shall be capable of filtering oil to the desired purity as

specified. The filtering elements shall not remove inhibitors and other additives from the lubricating oil.

4.04.02 The filter shall be designed for the maximum discharge pressure of the pump

supplying to the filter. The vessel shall be constructed of mild steel to IS:2062 and shall be designed in accordance with ASME pressure vessel code or equivalent. The vessel shall be fitted with a pressure relief valve.

4.04.03 A pressure gauge shall be installed at the outlet of the filter. 4.05.00 Suitable connection for filling the unit oil tank shall be provided and for this,

necessary oil filling pipes shall also be supplied which shall be connected to the bottom of steel oil funnel being provided at a suitable elevation. Steel oil funnels may be mounted on matching concrete funnels.

4.06.00 Interconnecting Piping, Valves and Accessories 4.06.01 The purification systems shall be completely piped incorporating the valves,

fittings, etc. 4.06.02 All interconnecting pipings and weld connections shall be designed in

accordance with ANSI code for pressure piping B 31.1. Carbon steel pipes smaller than 50 mm nominal bore shall be ASTM A-53 Grade B seamless, with wall thickness to at least schedule 80. Large bore pipes shall be to IS:1239, heavy grade and of seamless type.

4.06.03 Gate and check valves shall conform to IS:778 Class-I with union bonnet,

rising stem and screwed ends. Check valves shall be of lift disc type below 65 mm. All isolation valves in the oil line shall be of plug type. Plug valves shall be of malleable cast iron construction with union bonnet and screwed ends. Wherever possible, all screwed joints with the pipe shall be seal-welded by brazing process.

4.06.04 All relief valves shall be provided with hand levers to permit manual operation. 4.06.05 All strainers shall be Y-type with steel body and stainless steel screen of not

more than 20 mesh size. Screen opening area shall be at least four times the pipe cross-sectional area.

5.00.00 INSTRUMENTATION AND CONTROL Refer to Volume - IIE. 6.00.00 INSPECTION AND TESTING Refer to Volume – IIA.


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7.00.00 DATA, DRAWINGS AND INFORMATION REQUIRED Refer to Volume – IIA.


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SPECIFIC DESIGN CRITERIA

FOR TURBINE PURIFICATION SYSTEM

SL.NO. ITEM CRITERIA REMARKS 1.00.00 Type Centrifuge purifier. 2.00.00 Rating 20% per hour of the total

oil in TG system, or 6,000 liters per hour whichever is higher.

3.00.00 Outlet oil quality Free of moisture and

solid, suitable for turbine.

VVOOLLUUMMEE :: IIII--CC

SSEECCTTIIOONN--VVII

CCOONNDDEENNSSAATTEE PPOOLLIISSHHIINNGG SSYYSSTTEEMM


CONTENTS CLAUSE NO. DESCRIPTION PAGE NO. 1.00.00 GENERAL INFORMATION V.IIB/S-IV : 1 2.00.00 SCOPE OF SUPPLY V.IIB/S-IV : 1 3.00.00 DESIGN AND OPERATING FEATURES V.IIB/S-IV : 5 4.00.00 OPERATION AND CONTROL PHILOSOPHY V.IIB/S-IV : 9 5.00.00 DRAWINGS, DATA AND MANUALS V.IIB/S-IV : 12 ATTACHMENT ANNEXURE-I MAJOR EQUIPMENT AND ACCESSORIES FOR CONDENSATE POLISHING SYSTEM V.IIB/S-IV:13


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VOLUME : II-C

SECTION-VI

CONDENSATE POLISHING SYSTEM

1.00.0 GENERAL INFORMATION

1.01.00 On line Condensate Polishing System (CP System) is envisaged to achieve high order

of availability of various power cycle equipment as well as to ensure quick start up of the unit & continue the unit operation without any restriction by maintaining desired quality of condensate water as recommended by Boiler manufacturer. The CP System should also be capable of maintaining specified condensate quality with condenser tube leakage (sea water).

1.02.00 The proposed CP System shall comprise of 6 X 50% Condensate Polisher Mixed Beds

for 2 x 660 MW Units (i.e. 3 X 50% for each 660 MW Unit) and One (1) no. common External Regeneration System for 2 X 660 MW Units.

The Condensate Polisher Mixed Beds and associated pipe works, valves, instruments, control panels etc. shall be located at ground floor of Power House.

The External regeneration facilities comprising of Regeneration Vessels, air blowers, acid and alkali Measuring Tanks and Pumps shall be located in a separate place near and outside the Power House. The resins will be transferred to the Regeneration Area from the Condensate Polisher Mixed Beds and vice versa through a pipeline.

Operation of the complete CP System shall be through Programmable Logic Controller (PLC). The control of operation for the Polisher Vessels shall be from Local Control Panel with interlocks to the Control Desk of Regeneration area, with status indication of major parameters in main control room. The control of the CP System i.e. service and standby status of Polisher Vessels as well as Resin Transfer from Polisher Vessels to Regeneration Area and vice versa will be achieved through this Panel. The control for the external regeneration system shall be from the PLC based Control Desk located in the Local Control Room of CPU External regeneration building. A manually initiated automatic sequence for physical cleaning and chemical regeneration of the resins shall be provided.

The common inlet and outlet headers of each Polisher Vessel shall be connected to an emergency automatic bypass line. This bypass line shall include a differential pressure device, which on a high signal shall operate an automatic valve to open, bypassing the service vessels. In the event of excessive pressure differential between the condensate inlet and outlet header, this control valve shall open automatically to bypass requisite quantity of condensate to prevent this pressure differential from exceeding a preset limit when both vessels / one vessel / no vessel is in operation.

2.00.00 SCOPE OF SUPPLY

It is not the intent to completely specify all the details of design, construction and installation herein. Nevertheless, the equipment along with accessories and installation shall conform to a high standard of engineering design and workmanship and capable of performing continuous and satisfactorily. Details not furnished here shall be subject to approval.


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The Bidder shall be responsible for providing all material, equipment and services, specified or otherwise which are required to fulfill the intent of ensuring operability, maintainability and the reliability of the complete work covered under this specification. The equipment and accessories of CP System shall be complete to ensure the recommended condensate water quality both in terms of physical & chemical properties.

The CP System should consist of but not limited to the equipment and accessories as follows:

2.01.00 Six (6) nos. Condensate Polisher Mixed Beds (6x50%) (i.e. 3 x 50 % for each 660 MW Unit), each complete with condensate inlet and outlet connections, connections for resin transfer to and from vessels, bed support-cum-under drain system, inlet water distributors, all accessories and appurtenances etc. as required. CPU prefilter should be provided before mixed bed CPU.

2.02.00 External resin traps at the outlet of each of the Condensate Polisher Mixed Beds

each designed for in-place manual back wash facility. 2.03.00 Condensate inlet and outlet headers for Condensate Polisher Mixed Beds of each

660 MW Unit within the boundary limits. 2.04.00 Resin transfer lines of stainless steel construction between the External Regeneration

Vessels and the Condensate Polisher Mixed Beds along with all necessary supports, anchors etc for each 660 MW Unit.

2.05.00 Rinse water outlet header from Condensate Polisher Mixed Beds of each 660 MW

Unit to the boundary limit. 2.06.00 All necessary valves and fittings along with the actuators necessary for operation

from CP System Control Panel of each 660 MW Unit. These shall include suitable arrangement to prevent accidental over pressurization of the resin transfer pipeline and regeneration facilities connected to it, which are designed for pressure much lower than that of the Condensate Polisher Mixed Beds.

2.07.00 A common drain header for the Condensate Polisher Mixed Beds of each 660 MW

Unit. 2.08.00 All necessary drains, vents and sampling points along with isolation valves as

required. 2.09.00 Two (2) x 100% capacity blowers for each 660 MW Unit for Condensate Polisher

Mixed Beds (if required), each complete with electrical drive motor and all other accessories as required.

2.10.00 Two (2) nos. for each 660 MW Unit Rinse Recirculation Pumps, each complete with

electrical drive motor and all other accessories as required. 2.11.00 All instrumentation and controls as required for operation of the CP System. 2.12.00 Emergency bypass system between the condensate inlet and outlet headers with its

automatic valve, isolation valves on both sides and controls for each of Condensate Polisher Mixed Beds for each 660 MW Unit.

2.13.00 Instrument racks for mounting pressure and flow transmitters, pressure switches,

conductivity analyzers, etc. for each of Condensate Polisher Mixed Beds.


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2.14.00 Local Control Panel for each 660 MW Unit with Remote I/O unit, Conventional Instruments, Push Buttons, Selector Switches, Annunciation Facia, etc. for the control and safe operation of the CP System shall be provided. The PLC for CP System shall also have all necessary interfaces for interlocking / control and signal exchange with the PLC for Control Desk for Regeneration.

2.15.00 External Regeneration Vessels

The equipment and accessories for external regeneration as described below is tentative and for each set of 2 x 660 MW Units. Based on specific regeneration technology, the Bidder may adopt deviations with reference to Regeneration Vessels to make the system suitable in all respects for satisfactory operation.

2.15.01 One (1) no. Resin Separation & Cation Resin Regeneration Vessel complete with all

accessories. 2.15.02 One (1) no. Anion Resin Regeneration Vessel complete with all accessories. 2.15.03 One (1) no. Mixed Resin Storage Vessel complete with all accessories. 2.15.04 One (1) no. Resin Injection Hopper, complete with a water ejector system for resin

make-up complete with all accessories.

2.15.05 One (1) no. CPU regeneration water tank complete with all accessories. 2.15.06 One (1) no. Hydrochloric Acid Measuring Tank (CSRL-4.5mm natural Rubber lining)

(minimum one (1) day storage) for Polishers, complete with ejector system, integral pipe works, valves and all other accessories as required. The Acid required for CPU Measuring tank shall be drawn from Bulk acid storage tanks which is located near DM plant building

2.15.07 Two (2) nos. Hydrochloric Acid dosing Pumps each complete with electrical drive

motor and all other accessories as required. 2.15.08 One (1) no. Activated Carbon Filter for Alkali, complete with internals, integral pipe

works, valves and all other accessories as required. 2.15.09 One (1) no. Alkali Measuring Tank (CSRL-4.5mm natural Rubber lining) (minimum

one (1) day storage for 2x660MW) for Polishers, complete with ejector system, integral pipe works, valves and all other accessories as required. The Alkali required for CPU Measuring tank shall be drawn from Bulk alkali storage tanks which is located near DM plant building.

2.15.10 Two (2) nos. Alkali dosing Pumps, each complete with electrical drive motor and all

other accessories as required 2.15.11 Two (2) nos. (2 x 100%) (1W+1S) air blowers, each with electric motor drives, V-belt

drive with belt guard, air filters, silencers, discharge snubbers, for supply of process air required for regeneration of the resins.

2.15.12 Two (2) nos. (1W+1S) DM Water Regeneration / Resin Transfer Pumps each with

electric drive motor, one normally operating and the other standby, for water supply for chemical preparation / dosing and transfer of resin from Condensate Polisher Mixed Beds to Regeneration vessels and vice-versa, backwash etc.

2.15.13 One (1) no. Hot/Dilution water tank with Heater for regeneration of Anion Resins,

complete with integral pipe works, valves and all other accessories as required.


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2.15.14 Diluent DM Water Supply System, separately for acid and alkali, each provided with an automatic on-off valve, a throttling valve for setting of flow, a local flow indicator and a mixing tee where the chemicals get injected into the water stream.

2.15.15 Common Waste Effluent Header with one resin trap designed for in-place manual

backwash. 2.15.16 One (1) no. Neutralization Pit with two (2) compartments, each complete with all

accessories. The Acid & Alkali required for CPU Measuring tanks shall be drawn from Bulk acid/alkali storage tanks which is located near DM plant building.

2.15.17 One (1) no. Acid Measuring Tank (minimum one (1) day storage for 2x660MW) for

neutralization, complete with integral pipe works, valves and all other accessories as required.

2.15.18 One (1) no. Alkali Measuring Tank (minimum one (1) day storage for 2x660MW) for

neutralization, complete with integral pipe works, valves and all other accessories as required.

2.15.19 Two (2) nos. Neutralized Waste Transfer Pumps, each complete with electrical drive

motor and all other accessories as required.

2.15.20 Two (2) Nos. Root water tank of adequate capacity depending on the number of users and 8 hours requirement shall be provided for CPU Regeneration building to meet service & potable requirements. Polyethylene water storage tank conforming to IS: 12701 shall be used. The tank shall be complete with all fittings including float valve, stop cock etc.,

2.15.21 DM water piping for dilution, resin transfer, backwashing, flushing, rinsing etc. including

the DM water piping along with all supports and hangers between the Regeneration Facility and the CP System.

2.15.22 All necessary valves and fittings along with the actuators necessary for their remote

automatic operation. These shall include all drains, vents, sampling points with isolation valves as required.

2.15.23 All other integral and interconnected pipe works, valves, sump, gates, all types of pipe

supports, pipe and cable racks etc. for the entire Plant. 2.15.24 Operating platforms, ladders, supports and other structural works as required to facilitate

accessibility for operation and maintenance for all the Condensate Polisher Mixed Beds, Regeneration Vessels, Storage Tanks and other equipment.

2.15.25 Safety shower with eye wash. 2.15.26 Free Standing Control System with Programmable Logic Controller and CRT/Keyboard

based operator console & engineering console for the control and safe regeneration of CP System.

2.15.27 All drive motors / actuators associated with the system / equipment. 2.15.28 First fill of resins for all Condensate Polisher Mixed Beds, mixed storage vessel and

makeup resin hopper and also first fill of lubricants and grease. 2.15.29 All instruments, process switches, analysers, control valves, solenoid valves, etc. as

required. 2.15.30 All junction and solenoid Boxes.


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2.15.31 Supply of all screened, instrument and special cables. 2.15.32 All cable glands and lugs as required shall be provided by the Bidder. 2.15.33 Pneumatic & Process hook up tubing / piping.

2.15.34 All anchor bolts, foundation plates sleeves, nuts, inserts, etc. to be embedded in

concrete for entire CP System 2.15.35 Piping from Demineralised Water Tank for CPU regeneration and for resin transfer,

with piping valves and instrumentation. 2.15.36 All internals, fittings and appurtenances for these vessels. 2.15.37 Other tanks, piping, pumps as required. 2.15.38 DM water piping for dilution, resin transfer, backwashing, flushing, rinsing etc.

including the DM water piping along with all supports and hangers between the Regeneration Facility and the CP System.

2.15.39 All inter connecting piping, valves, fittings, accessories and instrumentation as

required within the terminal points specified. 3.00.00 DESIGN AND OPERATING FEATURES 3.01.00 The system shall be designed for 100% condensate polishing for each 660 MW Unit

corresponding to the maximum mass flow rate established with VWO condition of turbine with suitable bypass arrangement plus maximum heat cycle make-up.

3.02.00 Each of the Condensate Polisher Mixed Beds shall be designed to handle maximum

fifty percent (50%) of the system design flow rate for 660 MW Unit as addressed above and to suit the system design pressure as well as temperature.

3.03.00 Condensate Polisher Mixed Beds making up the system of each of 2 x 660 MW Units

will be connected to the condensate cycle of respective units and will treat the entire flow. The Condensate Polisher Mixed Beds should be capable of operating without any prior filtration of the condensate.

3.04.00 When condensate temperature exceeds 50°C for a particular 660 MW Unit or bypass

pressure difference reaches 0.35 Mpa, the bypass valve shall be 100 % opened automatically and the inlet/outlet of the Condensate Polisher Mixed Beds shall be closed to protect elements and resins inside the polisher.

3.05.00 After the bypass valve is 100 % opened, the bypass valve shall be closed manually.

Before closing the bypass valve, one needs to ensure that two Condensate Polisher Mixed Beds of respective 660 MW Unit have been put into operation.

3.06.00 Pressure differential across a Condensate Polisher Mixed Bed may also be judged by

the flow value. When the flow of one Condensate Polisher Mixed Bed under service is less than that of the other, it indicates that pressure differential inside the Condensate Polisher Mixed Bed with small flow is high and the resin inside it shall be regenerated.

3.07.00 The Bidder shall provide all instrumentations and controls to analyze the condensate as

per the requirements for safe and satisfactory operation of boiler. The system should be capable of producing the output characteristics which will be better than or equal to the specified conditions as prescribed by the Boiler Manufacturer or as specified elsewhere in this document whichever is more stringent. The system should be also capable of


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monitoring and maintaining the characteristics during unit start up, load variations and condenser tube leakage.

3.08.00 Under condenser tube leakage condition, the CP System shall be designed for ingress

of TDS (2000 ppb minimum) in addition to the influent contaminants under Normal Condition as stated above. The cation and anion load distribution for 2000 ppb TDS shall be based on circulating cooling water composition.

3.09.00 Under the Normal Condition, each Condensate Polisher Mixed Bed shall be designed to

operate in hydrogen cycle for not less than 168 hours of continuous operation, while maintaining the above treated condensate quality. Useful service run between regenerations during the above conditions of start-up and condenser tube leakage, shall not be less than 50 hours.

3.10.00 The bed cross section shall be such that the average velocity of condensate through it

does not exceed 120 m/hour at the design flow rate. 3.11.00 At the design flow rate, the pressure drop between inlet and outlet flanges of the

polisher Condensate Polisher Mixed Beds with clean resin bed shall not exceed 2.0 bar. This pressure drop shall include losses due to entrance and exit nozzles, distributors, underdrains, resins and the effluent resin traps. Maximum pressure drop under dirty conditions will be restricted to about 3.5 bar including the pressure drop across effluent resin traps.

3.12.00 Exchange Resins

The Bidder shall provide suitable resins for the Condensate Polisher Mixed Beds, Mixed Resin Storage Vessel and Resin Makeup Hopper. The Cation resin shall be strong acid, with sulfonic acid functional group to the regenerated with Hydrochloric Acid. The anion resin shall be strong base, with quaternary ammonium (Type-I) functional group to be regenerated with Sodium Hydroxide. Insert resin, if used, shall be non-ionic compatible with the above resins. A minimum resin ratio of 1.5 to 1 (Cation: Anion) will be provided. After separation, anion resin in the Cation resin shall be less than 0.1 % and Cation resin in the anion resin shall be less than 0.1 %. Deration factor of 10% for all resins shall be considered while calculating the quantity of resin to be supplied.

The resins furnished shall be of Rohm and Hass/ Dowex/ Duolite make. The effective depth of the mixed resin bed in the condensate polisher Condensate Polisher Mixed Beds shall not be less than 1100 mm.

The resin strength and other physical properties shall be suitable to withstand the design pressures in the system.

The resins selected must have been in use in Condensate Polishing plants capable of producing water as specified or better, for a period of not less than three (3) years.

The resin charge shall consist of material properly selected, washed, processed and graded to provide the guaranteed capacity and life. The resin shall have adequate


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abrasion resistance during its guaranteed life. The mixed bed exchangers shall contain a mixture of strong acid cation and strong base anion resins to remove the last traces of ions. The discharge of the mixed bed exchangers shall be neutral and demineralised. The mixed bed exchanger shall be designed as a single-chamber downstream filter with lower nozzle plate. The filter shall be filled with strong acid cation and strong basic anion resin. During the loading the resins shall be well mixed and have the effect of an endless chain of cation and anion exchangers. For the regeneration process, separate vessels shall be used.

3.13.00 Cation resins shall be regenerated by dilution of technical grade hydrochloric acid to

IS:265 (concentration 30-33% by volume) and anion resins by dilution of sodium hydroxide, rayon grade to IS:252 available as 48% lye. For calculations regeneration temperature should be taken as 25°C.

3.14.00 The regeneration process offered by the Bidder, shall be of proven design and shall

essentially be the same process for which the Bidder have experience and shall give proper resin separation method compatible with the desired treated water quality. The Bidder shall include inert resin in the system if it is felt that it helps in better resin separation.

In case, after separation of resins, if there are undesired contaminant resins, the Bidder shall provide a system either to eliminate this cross contamination of resins or to nullify the detrimental effect of entrapped resins to the effluent quality. There shall be a resin trap after each cation and mixed bed unit. If nozzles of cation exchanger shall be broken, no resin can get into the mixed bed exchanger. If nozzles of the mixed bed filter shall be broken, no resin can remove into the water steam circuit.

The guaranteed chemical consumption figures must be supported by relevant published data such as performance of the resin system, statistical data on resin losses and actual field performances of plants using a similar technique, indicating the quantity of chemicals required for regeneration, in particular, besides other parameters. The data on the chemical consumption figures and the calculations furnished by the Bidder shall be the primary basis of checking the guaranteed parameters during evaluation. The operating exchange capacity and regeneration levels shall be vetted by resin manufacturer and the Bidder must furnish the resin performance curves specially applicable for this project. Regeneration wastewater and the drain disposal of the bund of the chemical storage tanks shall be collected in the neutralization pit. Facility for addition of acid/alkali to neutralize the effluent shall also be provided. The neutralized effluent shall be finally disposed to the effluent waste water treatment plant by two neutralization pumps, each 100 % capacity (2 x 100 %).

3.15.00 The free board in various vessels shall be as indicated below : Vessel Percentage

Mixed Bed Polisher : 100 %

Resin Separation & Cation Resin Regeneration Vessel : 100 %

Anion regeneration vessel : 100 %

Mixed Resin Storage Vessel : 80 %

Resin Make Up Hopper : 80 % 3.16.00 The common influent and effluent header of Condensate Polisher Mixed Beds will be


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connected to an automatic bypass line to be provided. This bypass line shall include a differential pressure device which on a high signal will cause an automatic valve to open, bypassing the Condensate Polisher Mixed Beds. Automatic bypass line shall be provided with a butterfly type control valve and wafer type butterfly isolation valves (resilient material seated, to ensure bubble-tight shut off) on the upstream and downstream sides of the control valve. In the event of excessive pressure differential between the condensate inlet and outlet headers, this control valve will open automatically to bypass requisite quantity of condensate to prevent this pressure differential from exceeding a preset limit when both Beds/one Bed/no Bed are/is in operation.

3.17.00 The control system shall be so designed that the Control valve is able to bypass 50% of

rated flow when any of the Condensate Polisher Mixed Beds is out of service and 100% of flow when both the Condensate Polisher Mixed Beds are out of service.

3.18.00 Under normal conditions, Condensate Polisher Mixed Bed will hold a complete charge

of freshly regenerated and mixed resin, ready for use. For regeneration, resin from the exhausted Condensate Polisher Mixed Bed will be transferred hydraulically. The empty Condensate Polisher Mixed Bed will then be filled up with already regenerated resin available in the regeneration facility. This Condensate Polisher Mixed Bed shall come into service soon after prerequisite condition is satisfied or as and when desired by the operator. In the meantime, the exhausted resin charge will be cleaned, separated, regenerated, mixed and rinsed before being stored for the next use.

3.19.00 The Bidder shall provide a hopper type tank for resin make-up, using water slurry, to the

condensate polishing systems. This make-up system will constitute a portion of the condensate polishing external regeneration system. The resin hopper shall have a conical bottom and a flat top. The top shall have hinged port, having a lifting handle of sufficient size for easy resin loading. The resin shall discharge through a bottom connection to a water ejector for transport. Water shall be added to the hopper to assist in the resin transfer. The ejector discharge shall be led to the resin regeneration vessels. Demineralized water shall be used throughout for the resin transfer. Piping of the resin make-up system shall be under the scope of the Bidder as a part of the external resin regeneration system.

3.20.00 Each Condensate Polisher Mixed Bed shall be provided with resin trap on effluent line.

The resin trap in these lines shall be flanged at one end and will be connected at the end of the respective pipeline. The other end shall be open to the drain so that the flow can be seen to check the choking of the trap.

3.21.00 DM water, acid/alkali piping shall be of CSRL (Carbon steel rubber lined) for sizes 40

mm NB and above. The Carbon steel piping shall conform to IS 1239 Part I (heavy)/IS 3589 or equivalent. The fittings provided shall be as per ASME SA 234 Gr. WPB/IS 1239 Part II or equivalent. Inside surface of fittings to be rubber lined. The dimensions of the fittings shall be as per ANSI B 16.9 Flange ends to ANSI B 16.5.

3.22.00 The resin transfer piping shall be of Stainless Steel material to ASTM A 312 TP 304.

3.23.00 For sizes below 40 mm NB SS piping to ASTM A 312 TP 304 Sch 40 S shall be

provided. The fittings shall be of forged stainless steel to ASME SA 182 F 304 with SW ends to ANSI B 16.11

3.24.00 The minimum design concentrations of various contaminants envisaged to be present

in the condensate at inlet of CP System shall be considered as follows:

Contaminant Unit Normal Condition Start Up Condition Ammonia ppb 50 minimum Total Dissolved Solids ppb 100 minimum 2000 minimum


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(TDS, ammonia excluded) Copper ppb 5 minimum Total ferric iron ppb 50 minimum pH value (polisher runs at 250C with H/OH mode)

8.8 - 9.5

Chloride (as Cl) ppb 10 minimum Sodium (as Na) ppb 10 minimum Silica (as SiO2) ppb 25 minimum 150 minimum Crud (mostly black oxide of iron)

ppb 100 minimum 1000 minimum

Conductivity (at 250C) µS/cm 0.3 minimum 3.25.00 The CP System shall be designed to deliver the treated condensate as given below or

as recommended by the Boiler manufacturer whichever are more stringent.

Contaminant Unit Normal Condition

Start Up Condition

Tube Leakage condition

Total Dissolved Solids ppb < 20 < 50 Silica (as SiO2) ppb < 5 < 15 < 15 Total Ferric Iron ppb < 5 < 100 Total copper ppb Below

detectable limit < 1

pH value (runs in H/OH mode)

6.5 - 7.5 6.5 - 7.5

Electric conductivity after hydrogen column (25oC)

µS/cm < 0.1 < 0.2

3.26.00 Guarantee The bidder shall specify: a) The chemical - physical properties of the outlet water for specified inlet

conditions. b) Pressure drop across the system at different flow rates. c) Resin exchange capacities, loss Per Annum and regenerating level. 4.00.00 OPERATION AND CONTROL PHILOSOPHY

The control of operation for the Condensate Polisher Mixed Beds shall be from local free standing programmable logic controller based Control Panel with interlocks to the remote Control Desk for Regeneration System. The CP system panel for each 660 MW Unit shall be located in the ground floor of Power House. The control of the CP System i.e. service and standby status of Polisher Vessels as well as Resin Transfer from Condensate Polisher Mixed Beds to Regeneration Area and vice versa will be achieved through this Panel. This panel shall show the operating mode of each Condensate Polisher Mixed Bed (in service, on standby, resin transfer, rinsing down etc.) the position of all automatic valves, operating parameters (such as flow conductivity, silica levels, differential pressure etc.) and alarm conditions. A mimic diagram shall be provided on the front of the control panel. Status of various valves


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shall be indicated by LED’s on the mimic diagram. Facility to control the CP System from the Main Control Room shall also be provided.

The control for the external regeneration system shall be from the PLC based Control Desk located in a separate Control Room at Regeneration Area. This shall clearly show the status of each concerned Condensate Polisher Mixed Bed. This Control Desk shall be interlocked with the local control panel of Condensate Polisher Mixed Beds. This Desk will provide a manually initiated automatic sequence for physical cleaning and chemical regeneration of the resins and show the status of the cycle at all times. This Desk shall also contain all controls and accessories for the acid and alkali solution preparation and dosing system. The regeneration control Desk shall also control the sequences of Resin Transfer – i.e. to transfer resin from the Condensate Polisher Mixed Bed to the external regeneration facility and to receive freshly regenerated resin from the regeneration facility– this involves depressurization of the Condensate Polisher Mixed Bed, water sluicing of exhausted resins to the regeneration system, draining the Condensate Polisher Mixed Bed to the condenser hotwell, receiving a water slurry of fresh resin from the regeneration system and finally completely filling the vessel with condensate.

Condensate Polisher Mixed Bed Operation

Service flow rate for each Condensate Polisher Mixed Bed shall be monitored by panel mounted flow indicators. During periods of low condensate flow the operator may select to remove one of the vessels from service by a manually initiated automatic sequence. A differential pressure switch installed between the influent and effluent headers will on a high signal cause an annunciator alarm. By observing the individual vessel flow indicators, or conductivity at vessel outlet the operator can determine which vessel is contributing most to the pressure drop and is in need of resin cleaning/regeneration.

Panel mounted conductivity indicators shall monitor the polishing system influent and effluent streams as well as the discharge of each Condensate Polisher Mixed Bed. A high influent conductivity annunciator alarm will alert the plant operator that a problem condition such as air or condenser cooling water leakage has occurred. This conductivity analyzer shall also provide contacts for an alarm at the power station main control room. A high conductivity annunciator alarm on outlet of Condensate Polisher Mixed Bed will alert the operator to the need for regeneration of a Condensate Polisher Mixed Bed.

Condensate Polisher Mixed Bed shall be automatically placed in service following, manual pushbutton initiation from the control panel. The automatic sequence shall include steps for pressurization of the Condensate Polisher Mixed Bed, a pre-service rinse and placing in service.

The pre-service rinse shall be time controlled. If the conductivity of the Condensate Polisher Mixed Bed effluent is not acceptable at the end of the pre-service rise, a rinse overtime alarm shall be sounded and the pre-service rinse continued for a second timed period. If an acceptable Condensate Polisher Mixed Bed effluent is not reached by the end of the second pre-service rinse, a pre-service rinse failure alarm shall be sounded and the vessel shall be automatically returned to standby. If acceptable conductivity at outlet of Condensate Polisher Mixed Bed is attained at the end of the first rinse or during the second rinse, the vessel shall automatically be placed in service. Interlocks shall be provided to prevent placing a vessel into the service mode while resin is being transferred.

The rinse recycle shall be manually initiated full automatic sequence. This sequence shall include a rinse down step using condensate at a rate of 0.4 to 0.6 cu.m / min / sq.m until effluent quality is acceptable for boiler feed water. The effluent quality shall



DCPL-11Z02

be determined by conductivity monitoring of the rinse water outlet, which is for recycle. A panel mounted conductivity indicator shall be interlocked to prevent advancing of the automatic sequence until the rinse down is complete.

Condensate Polisher Mixed Beds shall be automatically removed from service following manual push button initiation from the control panel.

Exhaustion of a Condensate Polisher Mixed Bed shall be annunciated by any of the following:

a) High differential pressure across the polisher battery.

b) High effluent conductivity from an operating vessel.

c) High effluent silica from an operating vessel.

d) Pre-set volume of condensate treated in an operating vessel. When the differential pressure across the Condensate Polisher Mixed Bed header reaches the high set point level an alarm shall sound and by pass valve shall be automatically opened by a signal from the control system. The sample system for a Condensate Polisher Mixed Bed shall be taken out of service when the Condensate Polisher Mixed Bed is not in service or pre-service rinse.

The alarms for a Condensate Polisher Mixed Bed shall be disabled when the Condensate Polisher Mixed Bed is not in service or pre-service rinse.

Resin Transfer Mode

The sequence for resin Transfer from Condensate Polisher Mixed Bed to Regeneration Vessel and Resin Transfer from Regeneration Vessel to Condensate Polisher Mixed Bed shall be initiated from the condensate polishing unit control panel but shall be controlled by the programmable logic controller in the Regeneration control panel.

Manually initiated automatic sequences shall be provided for transferring resin from a Condensate Polisher Mixed Bed to the remote regeneration facility for physical cleaning and chemical regeneration and for returning fresh resin to that Condensate Polisher Mixed Bed.

The transfer of resin from the Condensate Polisher Mixed Bed shall include isolation of the Condensate Polisher Mixed Bed, hydraulic transfer of the resin to the external regeneration. The return of fresh resin to the empty Condensate Polisher Mixed Bed shall include the hydraulic transfer from the resin storage vessel of the external regeneration system using demineralized water. After receiving fresh resin the Condensate Polisher Mixed Bed will remain in the ‘Off’ position until returned to service by the operator. Resin transfer from a Condensate Polisher Mixed Bed to the regeneration vessel shall be automatic following manual pushbutton initiation from the control panel. The resin transfer sequence shall be interlocked to prevent resin transfer in any of the following situations:

a) Unsuccessful completion of a previous chemical regeneration of physical

cleaning sequence in the external regeneration system.



DCPL-11Z02

b) The Condensate Polisher Mixed Bed condensate inlet and outlet valves not closed.

c) High pressure in the polisher Condensate Polisher Mixed Bed.

5.00.00 DRAWINGS, DATA AND MANUALS 5.01.00 To be submitted with the bid:

The Bidder shall submit the following along with his formal proposal besides the different information required as indicated elsewhere in this specification.

5.01.01 Schematic flow and Instrumentation Diagrams 5.01.02 Lay out drawings 5.01.03 Characteristic curves for pumps and blower. 5.01.04 Power consumption data 5.01.05 Preliminary foundation drawings 5.01.06 Cross sectional drawings of major components of system. 5.01.07 Equipment GA, Layout, interlock, Instrument List, Instrument Data Sheet Alarm List,

Local Control Panel GA and Layout, Technical literature, Operational write up with logic diagram.

5.02.0 Drawing/Document To Be Submitted After Award 5.02.01 Final version of all drawings/documents listed in 6.01.00 above. 5.02.02 Detailed dimensional drawings. 5.02.03 Piping layout with sectional views. 5.02.04 Foundation load and support load data.


VOL-II-C-SEC-VI-ANX-I - 13

DCPL-11Z02

MAJOR EQUIPMENT AND ACCESSORIES FOR

CONDENSATE POLISHING SYSTEM 1.0 CONDENSATE POLISHER (MIXED BEDS) VESSELS:

i. Number of unit Six (6) [3 x 50 % for each 660 MW Unit]

ii. Description of each unit

iii. Design flow per unit (Net), m3/hr As per Tender Specification

iv. Design continuous service period between two successive regenerations under different conditions, hrs

As per Tender Specification

v. Treated water quality As per Tender Specification

vi. Media inside the vessel Strongly acidic high capacity polystyrene resin and Type-I strongly basic high capacity.

vii. Percentage deairation to be considered on design exchange capacity for design of the system

Minimum 10 %

viii. Depth of the bed, mm As per Tender Specification

ix. Free Board % of Bed Depth Not less than 100%

x. Regenerant Chemical Dilute Hydrochloric Acid and Dilute Sodium Hydroxide

xi. Design flow velocity, m/hr Not more than 120

xii. Design Temperature 600C

xiii. Design Pressure Design pressure should be the maximum expected pressure to which the vessels may be subjected plus 5% extra margin. Maximum expected pressure for vessels placed in the discharge line of pumps shall be based on the shut-off head of the pumps plus static head at pump suction, if any.

xiv. Material of construction

Shell SA 516 Gr. 70 / RL.

Head SA 516 Gr. 70 / RL.

Inside protection Inside lined with Natural Rubber [4.5 mm thick in (3) layers]

2.0 RESIN SEPARATION AND CATION RESIN REGENERATION VESSEL

i. Number of unit One (1) no. vessel common for 2 x 660 MW Units

ii. Depth of the bed, mm As per Tender Specification

iii. Free Board % of Bed Depth Not less than 100%

iv. Design Temperature 600C

v. Design Pressure Design pressure should be the maximum expected pressure to which the vessel may be subjected plus 5% extra margin. Maximum expected pressure for vessels placed in the discharge line of pumps shall be based on the shut-off head of the pumps



DCPL-11Z02

plus static head at pump suction, if any.

vi. Material of construction

vii. Shell SA 516 Gr. 70 / RL.

viii. Head SA 516 Gr. 70 / RL.

ix. Inside protection Inside lined with Natural Rubber [4.5 mm thick in (3) layers]

3.0 ANION RESIN REGENERATION VESSEL





v. Design Pressure Design pressure should be the maximum expected pressure to which the vessel may be subjected plus 5% extra margin. Maximum expected pressure for vessels placed in the discharge line of pumps shall be based on the shut-off head of the pumps plus static head at pump suction, if any.





4.0 MIXED RESIN STORAGE VESSEL





v. Design Pressure Design pressure should be the maximum expected pressure to which the vessel may be subjected plus 5% extra margin. Maximum expected pressure for vessels placed in the discharge line of pumps shall be based on the shut-off head of the pumps plus static head at pump suction, if any.





5.0 RESIN MAKEUP HOPPER


ii. Free Board % of Bed Depth Not less than 80%

iii. Design Temperature 600C



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iv. Design Pressure Design pressure should be the maximum expected pressure to which the vessel may be subjected plus 5% extra margin. Maximum expected pressure for vessels placed in the discharge line of pumps shall be based on the shut-off head of the pumps plus static head at pump suction, if any.

v. Material of construction

Shell IS 2062 Gr. B

Head IS 2062 Gr. B


6.0 NEUTRALISATION PIT

i. Number required One (1) no. Pit with two (2) compartments, common for 2 x 660 MW Units

ii. Type Necessary air grid arrangement of polypropylene construction shall be provided in each compartment for effective neutralization of the waste effluent.

iii. Effective Capacity of each compartment

Adequate to hold the quantity of waste effluent generated due to single regeneration of Condensate Polisher Mixed Beds of plus 20% overall margin.

iv. MOC RCC. minimum Inside lined with PVC sheet (3 mm thick).

7.0 DILUTION/HOT WATER TANK WITH HEATER

Dilution Water Heater

i. Number required One (1) no. common for 2 x 660 MW Units

ii. Type Vertical cylindrical with dished ends.

iii. Type of fluid to be handled DM Water

iv. Effective capacity Suitable to meet the requirements for alkali injection and alkali displacement in course of single regeneration of a Condensate Polisher Mixed Bed, plus 20% margin.

v. MOC

Dished Ends SA 516 Gr. 70 / RL.


Inside Protection Natural Rubber (suitable for temperature 70oC- 8 mm thick in (6) layers)

8.0 PUMPS

Rinse Recirculation

Pumps

Acid unloading

pumps

Alkali unloading

Pumps

Acid dosing pumps

Alkali dosing Pumps

DM Water Regeneration/

Resin Transfer

Pump



DCPL-11Z02

i. Number required

Four (4) Nos. Two (2) nos. for each 660 MW Unit-One

(1) no. in operation and

other as standby

Two (2) nos. for 2 x 660 MW Units-One (1) no. in operation and other as

standby

Two (2) nos. for 2 x 660 MW Units-One (1) no. in operation and other as

standby

Two (2) nos. for 2 x 660 MW Units-

One (1) no. in operation and

other as standby

Two (2) nos. for 2 x 660 MW Units-

One (1) no. in operation and

other as standby

Two (2) nos. for 2 x 660 MW

Units-One (1) no. in operation

and other as standby

Description (applicable for each pump)

ii. Type Horizontal Centrifugal

Horizontal Centrifugal


Positive displacement hydraulically

operated diaphragm

type

Positive displacement hydraulically

operated diaphragm

type


iii. Location Indoor Outdoor with cover

Outdoor with cover

Indoor Indoor Indoor

iv. Duty Intermittent Intermittent Intermittent Intermittent Intermittent Intermittent

v. Rated capacity, Cu.m/hr.

To be selected by the Bidder as necessary to meet the system requirements.

vi. Head to bedeveloped


vii. Material of Construction

Casing Stainless Steel type

316

PP (Polypropyle

ne)

Stainless Steel type

304

PP (Polypropylen

e)

PP (Polypropylen

e)


316

Impeller Stainless Steel type

316

PP (Polypropyle

ne)


304

Diaphragm-Chemically inert teflon

Diaphragm-Chemically inert teflon


316

Shaft Stainless Steel type

410

Hardened Carbon Steel

- EN 19


410


- EN 19


- EN 19


410

9.0 BLOWERS

Air Blowers for Condensate Polisher Mixed Beds

Air Blowers for Regeneration

i. Numbers required Four (4) nos. [Two (2) nos. for each 660 MW Unit -

One in operation and other as stand-by].

Two (2) nos. for 2 x 660 MW Units-One in operation and

other as stand-by].

ii. Type Rotary, Twin Lobe, oil free, positive displacement

Rotary, Twin Lobe, oil free, positive displacement

iii. Location Indoor Indoor.

iv. Fluid to be handled Atmospheric air Atmospheric air

v. Service To supply air to service vessels To supply air to Regeneration vessels

vi. Duty Intermittent Intermittent.



DCPL-11Z02

vii. Rated capacity, Cu.m/hr.


viii. Head to be developed To be selected by the Bidder as necessary to meet the system requirements.

ix. Material of Construction Casing – Cast Iron Casing – Cast Iron

Shaft - Hardened carbon steel EN-19 Shaft - Hardened carbon steel EN-19

VOLUME : II-C

SECTION-VII

ON LINE TUBE CLEANING SYSTEM


CONTENT

CLAUSE NO. DESCRIPTION PAGE NO. 1.00.00 SCOPE OF WORK V.IIC/S-VII : 1 2.00.00 CODES AND STANDARDS V.IIC/S-VII : 2 3.00.00 DESIGN AND MANUFACTURING/ CONSTRUCTION REQUIREMENT V.IIC/S-VII : 4 4.00.00 OPERATING CONDITIONS/REQUIREMENT V.IIC/S-VII : 9 5.00.00 INSPECTION AND TESTING V.IIC/S-VII : 9 6.00.00 DRAWINGS, DATA AND MANUALS V.IIC/S-VII : 11 ATTACHMENT ANNEXURE-I DATA SPECIFICATION SHEET FOR CONDENSER ON LINE TUBE CLEANING SYSTEM AND DEBRIS FILTER V.IIC/S-VII : 12


VOL-II-C-SEC-VII/1

DCPL-11Z02

VOLUME : II-C

SECTION-VII

ON LINE TUBE CLEANING SYSTEM

1.00.00 SCOPE OF WORK

The scope of supply under On Line Tube Cleaning System for each condenser of each unit shall be as below. Items not mentioned but deemed necessary by the Bidder for making the system completely reliable and efficient shall also be included along with mandatory spares.

a) Each Condenser on Line Tube Cleaning Systems consisting of -

i) One (1) no. Ball separator on the C.W. outlet pipes. Each ball separator shall consist of Carbon Steel flanged shell, ball separator screens, ball extraction arrangement, drive units for actuation of screens, differential pressure measuring system etc.

ii) One (1) no. ball re-circulation units complete with pumps, drive

motors, ball collectors, etc. iii) One (1) no. Ball Re-circulation Monitor and ball injection

arrangement with nozzles.

b) One (1) no. Debris filter in the C.W. inlet lines. Each Debris Filter shall consist of Carbon Steel flanged shell, filter screen, debris flushing and extraction assembly, drive units for operation of debris flushing assembly, differential pressure measuring system etc.

c) One (1) set of debris flushing and discharge system complete with

flushing pumps, drive motors, debris discharge butterfly valves with electric actuators, etc.

d) All interconnecting pipes with necessary valves, fittings, pipe supports

etc. for connecting ball separator section to ball re-circulating skid, re-circulating skid to injection point, Debris Filter to debris discharge point on the C.W. outlet pipes at down stream of ball separator, all integral piping for debris flushing system and ball re-circulating skid, drain line, vent line, drain collectors (floor level), sample points with suitable valves etc.

e) All supporting steel structures for the equipment, piping and

instrument for the skid.

f) All foundation bolts and embedded inserts required for anchorage of machines, equipments, structures, and cable trays.


VOL-II-C-SEC-VII/2

DCPL-11Z02

g) Required number of cleaning balls (normal sponge balls as well as abrasive balls) for commissioning of the system.

h) The scope of Instrumentation & Control shall include but not be limited

to the following : i) One (1) local control panel for each tube cleaning system with

installed local instrumentation, controls, alarms, completely wired. The control panel shall be provided with segregated power compartment. This local control panel shall be supplied with anti vibrations supports.

ii) One (1) local control panel for each debris filtration unit with

installed local instrumentation, controls, and alarms, completely wired. The control panel shall be provided with segregated power compartment. This local control panel shall be supplied with anti vibrations supports.

iii) All field and local control board mounted instruments along

with accessories; their supports and all logic necessary to satisfy the requirements described in this specification.

iv) All necessary Pressure Gauges, Differential Pressure Gauges,

D.P. Transmitters, Ball Monitoring Units required for the functional completeness of the above systems/equipments.

v) Instrumentation and control cables along with accessories as

necessary.

i) Cable trays, conduits, their supports and all mounting materials within the skid.

2.00.00 CODES AND STANDARDS

“The design, material, construction, manufacture, inspection, testing and performance of Condenser on-line tube cleaning system and debris filters for Auxiliary system and associated equipment shall comply with the latest edition of all currently applicable standards, statutory regulations and safety codes in the locality where the equipment will be installed. Nothing in this specification shall be construed to relieve the Bidder of his responsibility. In case of conflict between the standards, stringent specifications out of these standards shall govern, whereas in case of conflict between the standards and this specification, requirements of this specification shall govern. Other National standards are acceptable if they are established to be equal to or superior to the listed standards. In all such cases, however, copies of English translation of such National standards shall be attached to the tender. The tenders not complying with this requirement are liable for rejection”. The design, materials requirement, manufacture, testing and performance requirements of the condenser On Line Tube Cleaning System shall conform to the latest edition of the following codes, standards, specification and regulation: a) Standards of the Hydraulic Institute of USA.


VOL-II-C-SEC-VII/3

DCPL-11Z02

b) PTC 8.2 : Power Test Codes - Centrifugal pumps.

c) ASME Section VIII: Pressure Vessel Code, 2001

c) ASTM - American Society for Testing & Materials.

d) American National Standards (ANSI) on - i) Steel Pipe Flanges and Flanged Fittings (B 16.5) ii) Steel Fittings S.W. and Threaded (B 16.11) iii) Butt welding ends-Pipe, valves, & fittings (B16.25). iv) Valves – Flanged, Threaded and Welding End (B 16.34)

e) American Society for Non destructive Testing (SNT-TC-1A) f) NEMA : National Electrical Manufacturer's Association g) OSHA : Occupational Safety and Health Act h) IEEE : Institute of Electronics and Electrical Engineers i) ISA : Instrument Society of America Other standards such as IEC, VDI, DIN, BS, IS etc. shall also be accepted

subject to the owner's approval for which the Bidder shall furnish along with the bid adequate information to justify that these standards are equivalent or superior to the standards mentioned above. For such alternate standards, which are not normally published in English, bidder shall also furnish a complete translation for them.

Technical requirements of the condenser On Line Tube Cleaning System

have been indicated in the "Data Sheet" in Annexure-I of this specification. In case of any contradiction between the above standards and data sheets, the stipulations in the data sheet shall prevail and shall be binding on the Contractor.

2.01.00 General Description

For maintenance of degree of cleanliness of the condenser tubes, this on load ball re-circulation type tube cleaning system and debris filters at CW inlet line to condenser will be employed. The on line condenser tube cleaning system shall maintain a circulation of resilient balls in a closed loop through the condenser tubes. Thus, while passing through the tubes, the balls get deformed thereby cleaning the inner surface of the tubes. The balls will be injected at the C.W. inlet pipe by ball recirculation pumps, which subsequently will be distributed evenly throughout the cross-section of the condenser tube sheet to effect uniform cleaning of tubes. The balls after passing through the tubes will be taken out of the C.W. outlet pipes. The balls are then led to the C.W. inlet pipe once again for recirculation.


VOL-II-C-SEC-VII/4

DCPL-11Z02

3.00.00 DESIGN AND MANUFACTURING / CONSTRUCTION REQUIREMENT 3.01.00 Design Considerations

The online condenser tube cleaning system shall overcome fouling, scaling and clogging of tubes thru micro-fouling caused by sludge, corrosion products/micro-organisms etc. which may result due to increased cooling water temperature and reduction in heat transfer co-efficient particularly due to disturbances in the calcium-carbonate, carbon-dioxide equilibrium as well as by precipitation of calcium carbonate, silicate, calcium sulphate, magnesium salts etc.

Equipment/works offered shall be designed for high availability, high

reliability, low maintenance and ease of operation & maintenance. The Bidder shall specifically state the design features incorporated to achieve high degree of reliability, availability, operability and ease of maintenance. He shall also furnish details of availability records in plants stated in his experience list.

All similar parts of the equipment shall be made to gauge and shall be

interchangeable with and shall be made of same material and workmanship as the corresponding parts of the equipment. Where feasible common components shall be employed in different pieces of equipment in order to optimize the spares inventory and utilization.

3.02.00 General Performance Requirement 3.02.01 Performance requirements of the tube cleaning system and debris filter

covered by this specification are as follows : i) The cleanliness of the condenser tubes utilising continuous operation

of the system such that the contribution of the tube waterside fouling to the variation of the condenser vacuum from its design value is negligible.

ii) The pressure drop across the ball separator screens and debris filter

screens during normal cleaning operation shall be minimum (it should not be more than 30 millibar).

iii) In the automatic system, sequential operations of various equipment

in tube cleaning system must be performed in such a manner that there is absolutely no loss of balls during any cleaning or washing mode of operation of the system.

iv) The online condenser tube cleaning system shall perform satisfactorily

under the specified flow indicated in the technical specification (in the condenser) and shall be capable of removing the various forms of fouling and scaling from condenser tubes. The condenser back pressure / overall heat transfer co-efficient shall be guaranteed to the close limits as specified as long as the tube cleaning system is in operation.

v) The quantity of cleaning balls worn out and/or lost shall be as

minimum as possible. The quantity of cleaning balls required for an operating period of one year shall be guaranteed.


VOL-II-C-SEC-VII/5

DCPL-11Z02

vi) Bidder shall prove the guaranteed performance figures for each unit during the performance testing. The performance testing of the complete tube cleaning system will be done at site after its installation after twelve months from the initial trial.

vii) The Employer will do the mechanical and chemical cleaning of the

condenser of each unit when on line condenser tube cleaning system is to be commissioned and put into service for the first time. At this stage, the cleanliness of the condenser tube shall be assumed as 100%. This will ensure that condenser tubes are in clean condition when on line condenser tube cleaning system is commissioned.

viii) The temperature difference between condensate & C.W. outlet shall

be measured at the time of commissioning of the system after its operation is established. On completion of twelve months operation, when the ambient condition will be more or less same as at the time of commissioning the temperature difference between condensate & C.W. outlet will be measured and should be the same as it was at the time of commissioning, with similar ambient temperature conditions.

ix) The Employer shall conduct the performance guarantee test in

presence of the bidder immediately after completion of guarantee period, but in any case, not later than six weeks after the expiry of guarantee period.

x) The schedule for taking the performance guarantee test shall be

mutually agreed between Employer and the bidder. Any extension in the period beyond six weeks for completing performance guarantee test shall have to be mutually agreed to.

xi) The contractor shall prove the guaranteed performance figures during

the performance guarantee test. 3.02.02 Penalty For Poor Performance Of The System

Before commissioning and putting the online condenser tube cleaning system into service for the first time the Employer shall do the mechanical and chemical cleaning of the condenser tubes. This will ensure that condenser tubes are in 100% clean condition.

3.02.03 During the trial operation the temperature difference between condensate and CW outlet shall be measured after putting the unit on full load. The cleanliness of the condenser tubes shall be considered as 100% at this stage.

The operation of this system may be continuous/intermittent as mutually

decided by the Employer and contractor. On completion of twelve months operation of online condenser tube cleaning system, when the ambient conditions will be more or less same as at the time of commissioning of the system, the temperature difference of condensate and CW outlet will be measured and should be same as it was at the time of commissioning, with similar ambient temperature conditions.

If the guarantees specified are not achieved by the contractor, then the

contractor shall be given an opportunity to improve upon the performance &


VOL-II-C-SEC-VII/6

DCPL-11Z02

the performance shall be checked again after the corrections are carried out. If even after carrying out corrections in the system, the performance is not satisfactory, then the plant stands rejected.

3.02.04 During trial operation the cleanliness factor shall be calculated on the basis of

the ratio of the heat transfer rate obtained with the tube cleaning system in service for 12 months and the available Heat transfer rate at the time of commissioning (condenser tubes at 100% clean condition) of the system with similar ambient temperature conditions.

Heat Transfer rate will be calculated as per the standard formula for the

steam surface condenser and it will be denoted by Uf . . The operation of this system may be continuous/intermittent as mutually

decided by the Employer and the contractor. On completion of 12 months operation of online condenser tube cleaning system when the ambient conditions will be more or less similar to conditions as at the time of commissioning of the system, the heat transmission rate will be calculated and will be denoted by Uo.

The ratio of Uo/Uf will be calculated for the cleanliness factor Cf. The plant

stands rejected in the Cf is observed to be less than 85%. 3.02.05 The performance guarantee test shall be conducted by the Employer in

presence of the contractor immediately after completion of guarantee period but in any case not later than 6 weeks after the expiry of guarantee period. The schedule for taking the performance guarantee test shall be mutually agreed between the Employer and the contractor. Any extension in the period beyond six weeks for completing performance guarantee tests shall have to be mutually agreed to.

3.03.00 Constructional Features General Unless inconsistent with this specification, the supplier’s standard or usual

construction is desired. The equipment shall be capable of safe, reliable and continuous operation at

all conditions of circulating water flow through the condenser tubes maintaining the design cleanliness factor of the tubes.

Ball Separator The design of the ball separator section shall aim at the maximum rigidity of

the screens by adequate stiffening bars. The construction of the ball extraction area shall ensure smooth and reliable

removal of the balls out of the separator section. The separator shall have flanged ends and flange drilling shall conform to

AWWA C207 standard.


VOL-II-C-SEC-VII/7

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Ball Collector The size of the ball collector shall be determined by the number of condenser

tubes coming per path, the relevant ball circulation frequency and the cleaning ball diameter.

The integral non-return flap shall ensure no reverse flow in case of ball

recirculation pump-motor failure thereby avoiding any loss of balls. Ball injection system The design of the injection system shall be such that it performs an even

distribution of requisite cleaning balls at the C.W. inlet pipe so that each condenser tube receives a cleaning ball regularly at fairly short intervals.

Cleaning balls Resilient balls of proper hardness and correct size shall be selected based on

factors like tube material, nature of fouling expected, tube internal diameter and desired service life of the balls.

Only a single type of ball to cater for the entire range of tube fouling may not

adequate. The supplier shall furnish different types of balls as required in sufficient quantities to take care of all possibilities like (a) normal maintenance of tube cleanliness when function of the ball is more of that of polishing than removing of scales (b) removal of comparatively hard scale formed due to non-availability of the tube cleaning system for reasons like failure of the system, long shutdown of the generation unit, etc.

Schedule of Materials Materials of construction of components of various equipment covered by this

specification shall be as per data specification sheet. In selecting materials of construction of equipment, the Contractor shall pay

particular attention to the atmospheric conditions existing at the Site and the nature of material/fluid handled. Wherever deviations are taken in respect of materials specified, the reasons shall be spelt out clearly in the proposal.

All materials shall be new, and shall be of the quality most suited to the

proposed application. In as far as is possible, materials shall be in accordance with national or

international standard specifications and shall be used in accordance with national or international codes of practice. Where such standards or codes of practice are not available sufficient information shall be provided to allow the owner to assess the suitability of the material for the particular application.

All materials used shall have demonstrated lengthy satisfactory service in

similar or more arduous conditions to those proposed by the Contractor. Drive Motor Drive motor and actuators for valves and screen shall be as per Vol-IIF of this


VOL-II-C-SEC-VII/8

DCPL-11Z02

specification. 3.04.00 Instrumentation And Control

Operation of the condenser on line tube cleaning system and debris filters with necessary audio / visual alarm / indications will be initiated locally by the Programmable Logic Controller based Control Panel. The system shall be controlled from the local control panel, either in 'Auto' or 'Manual mode, by means of a selector switch. Following are the major control logics to be provided for operation of the automatic tube cleaning system. However, the bidder may offer additional control features also, if considered necessary by him for smooth and trouble-free operation of the system. Provision for manual over-ride of any automatic operation shall be made available in the panel. Potential free contacts for START/STOP signal interfaces with the MCC shall be provided.

a) Start-up of the cleaning system after manually feeding the requisite

number of balls into the collector : The above operation & control will be achieved through steps like

setting the selector switch on local control panel to "Auto" mode and pressing the push button to "system ON". Other steps will follow sequentially viz. tilting of the screens in the strainer section to "ball circulating position", starting of recirculation pump, turning the ball catching flap in the collector to "ball circulation" position, etc. In case of manual mode, all steps will be achieved manually by operating the corresponding push buttons.

b) Automatic shut-down of the cleaning system either periodically or as

per operator's requirement by pressing the push button from the local control panel.

Under "Auto" mode, pushing of "System OFF" push button shall

initiate the above operation, through steps like turning the ball catching flap in the collector to "ball catching" position, stopping the recirculation pump after a set period.

c) Monitoring of strainer section screen fouling by differential pressure

measuring system. d) Indicators & Alarms The following minimum indications shall be provided : i) Tube cleaning system ON-OFF ii) Pump ON-OFF iii) “Screen Operation” iv) DP High-Normal v) MOV "Open"-"Close"


VOL-II-C-SEC-VII/9

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vi) Various failure positions The following minimum alarms shall be provided : i) Pump tripped ii) DP - high and very high iii) M.O.V failure to open or close iv) Screen Actuator failure The above list of logics is not exhaustive and the supplier shall provide all

other control logics required for the safe and trouble-free operation of the system. Necessary interlocks, (e.g. recirculation pump will not run if the strainer section is in 'screen wash' position) for proper operation of the system shall also be provided. The supplier shall furnish the write-up and logic diagrams for interlock and protection.

4.00.00 OPERATING CONDITIONS / REQUIREMENTS 4.01.00 Operational Features

The tube cleaning system shall be semi automatic and shall be operated from local control panels.

4.02.00 Ball Separator Strainer Section and Differential Pressure Measuring System

During the normal cleaning mode the screens shall allow the circulating water

leaving the condenser to pass through with very little pressure drop across the screens. However, the cleaning balls coming out of the condenser tubes will be prevented from escaping. These balls will get collected over the separator screens and are extracted from the strainer section and pumped back to the system for re-cycling.

Whenever the pressure drop across the strainer, as sensed by the differential

pressure measuring system, exceeds a pre-set limit, annunciation shall appear in the local panel.

4.03.00 Recirculation Pump and Injection Nozzles The recirculation pump will extract the balls from the ball separator strainer

section and push them through the ball collector to the ball injection nozzles. The ball injection nozzles shall point against the direction of the C.W. flow for better ball distribution.

5.00.00 INSPECTION AND TESTING The manufacturer shall conduct all tests and inspections (including stage

inspections, as necessary) required to ensure that the equipment offered by him conforms to the requirement of this specification. The particulars of the proposed tests and the procedures for the tests shall be submitted to the Purchaser for approval before conducting tests.


VOL-II-C-SEC-VII/10

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Test certificates for all tests shall be submitted to the purchaser for approval. 5.01.00 Material test All materials used for the manufacture of the equipment covered under this

specification will be of tested quality. Physical and chemical tests on materials shall be done to ensure the quality of the material offered. Test procedures and sampling shall be guided by the applicable test Codes and Standards. Components for which material test has been done and approved shall be stamped for identification.

Components viz. ball separators, debris filters, ball vessels, and ball recirculation pumps. debris flushing pumps, fabricated main flanges and counter flanges shall be subjected to Non-Destructive Testing as per following requirement and the acceptable limits shall be guided by relevant standard(s):

Visual Tests

All the parts/components shall be visually inspected in full (100%) for configuration, size, surface finish etc with approved drawings and documents.

Liquid Penetrant and Ultrasonic Tests i) All weldments, pressure containing parts of pumps (casing and shaft),

screen shaft, fabricated main flanges and counter flanges shall be surface inspected inside and outside by means of magnetic particle or liquid penetrant test to ensure freedom from cracks and other defects. Test procedure shall be in accordance with purchaser approved procedure.

ii) Ball separator/debris filter shell nozzles and flanges (>40 mm thk

plate), screen shaft and pressure containing parts of pumps made from forging shall be 100% ultrasonic tested in accordance with the relevant ASTM Standards.

Radiography Test All weldments of fabricated main flanges, counter flanges and screen

assembly shall be 100% radiographed and butt welding joints of pipe work will be at least 10% radiographed in accordance with Section VIII of the ASME Boiler and Pressure Vessel Code and shall comply with the Standards of Section VIII of the ASME Boiler and Pressure Vessel Code

5.02.00 Hydrostatic Testing Pump casing, ball separator shell, debris filter shell and the interconnecting

piping shall be hydrostatically tested at one and one-half times the design pressure.

5.03.00 Performance Testing Each pump in the tube cleaning system and debris flushing system shall be

tested to determine pump performance. Prior to performance tests, the pump


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supplier shall furnish the procedures and methods of testing to the purchaser for approval.

6.00.00 DRAWINGS, DATA AND MANUALS 6.01.00 To be submitted with the bid :

The Bidder shall submit the following along with his formal proposal besides the different information required as indicated elsewhere in this specification.

i) Piping and Instrumentation Diagram

ii) Equipment GA, Layout, interlock, Instrument List, Instrument Data Sheet Alarm List, Local Control Panel GA and Layout, Technical literature, Operational write up with logic diagram.

iii) Equipment load list and foundation design.

6.02.00 Drawing/Document To Be Submitted After Award Final version of all drawings/documents listed in 6.01.00 above.


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DATA SPECIFICATION SHEET

CONDENSER ON LINE TUBE CLEANING SYSTEM AND

DEBRIS FILTERS 1. Condenser Data No. of condensers per generating unit : As per TG manufacturer’s

system design/configuration. 2. Material of Construction a) Ball Separator Section i) Separator shell flanges : Carbon Steel as per IS:2062 or equivalent flanges as per AWWA- C207, Class-B ii) Separator shell : Carbon Steel as per IS: 2062 or equivalent with glass flake coating internal surface iii) Internals : SS 317L iv) Bolts & nuts in contact with circulating water : SS 317L b) Ball Recirculation pumps & debris flushing pumps i) Casing/ impeller : SA 351 CF8M ii) Shaft : SS 316 c) Ball Collector i) Housing : Stainless Steel ii) Internals : SS-317L d) Debris Filter i) Debris Filter shell : Carbon Steel as per IS: 2062 or equivalent with glass flake coating internal surface ii) Debris Filter shell flanges : Carbon Steel as per IS:2062 or equivalent flanges as per AWWA- C207, Class-B


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iii) Screen basket : SS 317L iv) Bolts & nuts in contact with circulating water : SS 317L e) Ball Valves i) Body : SA 351 CF8M ii) Ball : SA 351 CF8M iii) Stem : SS 316L f) Interconnecting piping i) Interconnecting piping & fittings

between Debris Filter to debris discharge point on the C.W. outlet pipes : Carbon Steel with inner

rubber lining ii) Interconnecting piping and fittings

between ball separator section to ball re-circulating skid and re-circulating skid to injection point : SS 317L

g) Details of cleaning balls for commissioning of the system

Normal sponge balls & abrasive balls

i) Type : Spherical ii) Number of balls per charge per : Bidder to decide system iii) No. of charges per system : To suit the system iv) Size : To suit the system

SWITCH YARD

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