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OC No. Total Sheets

DDC 067Document No. PP 067 M B01 0

146

DESIGN BASIS REPORT FOR

MECHANICAL


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POWER DIVISION THERMAX LIMITED

Project Document Title Doc. No. Rev. Sheet

2 x 60 MW THERMAL

POWER PLANT, IMFA,

ORISSA

DESIGN BASIS REPORT

MECHANICAL

PP 067 M B01 0 1 2

DESIGN BASIS REPORT MECHANICAL

INDEX

1. INTRODUCTION ...............................................................................................9

2. UNITS OF MEASUREMENT & ABBREVIATIONS.........................................10

2.1. UNITS OF MEASUREMENT .............................................................................10

2.2. ABBREVIATIONS............................................................................................10

3. CODES & STANDARDS.................................................................................11

4. POWER PLANT CONFIGURATION...............................................................14

4.1. PLANT CONFIGURATION ................................................................................14

4.2. PLANT STARTUP,OPERATION AND CONTROL PHILOSOPHY ..............................16

4 3 CUSTOMERS DESIGN INPUTS 16


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7.3.4. Pressure Gradient ............................................................................................. 47

7.3.5. Velocity Profile................................................................................................... 47

7.3.6. Safety valve details ........................................................................................... 48

7.3.6.1. Safety Valve Set Pressures .....................................................................................48

7.3.6.2. Safety Valve Relieving Capacity ..............................................................................48

7.3.7. Fuel, Limestone & Bed Material Consumption.................................................. 48

7.4. BOILER MOUNTINGS AND FITTINGS ................................................................49

7.4.1. Steam Drum ...................................................................................................... 49

7.4.2. Furnace headers ............................................................................................... 49

7.4.3. Drain Header..................................................................................................... 49

7.4.4. Superheater....................................................................................................... 50

7.4.5. Spray Water Line............................................................................................... 50

7.4.6. Economiser ....................................................................................................... 50

7.5. SOLID FUEL FIRING SYSTEM..........................................................................50

7.5.1. Fuel Bunker....................................................................................................... 51

7 5 2 Fuel Firing System 51


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7.13. ESP DESIGN BASIS .......................................................................................60

7.14. CHIMNEYDESIGN BASIS.............................................................................61

7.14.1. Calculation of Chimney Height....................................................................... 62

7.14.2. Calculation of Chimney Diameter................................................................... 62

7.14.3. Sketch of Chimney......................................................................................... 63

8. STEAM, FEED WATER AND CONDENSATE SYSTEM ................................63

8.1. STEAM SYSTEM............................................................................................63

8.1.1. Control Philosophy............................................................................................ 66

8.2. FEED WATER SYSTEM ..................................................................................66

8.2.1. Deaerator .......................................................................................................... 668.2.2. Boiler Feed Pumps............................................................................................ 68

8.2.3. HP Feed Water Heaters.................................................................................... 70

8.2.4. Feed Water Control Station.............................................................................. 70

8.2.5. Control Philosophy............................................................................................ 70

8.3. CONDENSATE SYSTEM..................................................................................71

8 3 1 S f C d 72


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9.2.1.2. System Sizing Calculation........................................................................................89

9.2.2. Auxiliary Cooling Water System For Auxiliaries ................................................ 91

9.2.2.1. System Description ..................................................................................................91

9.2.2.2. System Sizing Calculation........................................................................................92

9.2.3. Cooling Water Treatment Scheme.................................................................... 94

10. FUEL OIL SYSTEM.........................................................................................94

11. FUEL HANDLING SYSTEM............................................................................94

11.1. SYSTEM SIZING ............................................................................................95

11.2. SYSTEM DESCRIPTION ..................................................................................96

12. LIME STONE HANDLING SYSTEM .............................................................101

12.1. SYSTEM DESCRIPTION &SYSTEM SIZING .....................................................101

13. ASH HANDLING SYSTEM............................................................................102

13.1. SYSTEM DESCRIPTION ................................................................................102


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16. VENTILATION SYSTEM ...............................................................................117


16.1.1. Ventilation System for Power House Building & associated Areas.............. 117

16.1.2. Ventilation System for Auxiliary Buildings in Various Locations .................. 118

16.2. SYSTEM SIZING ..........................................................................................120

17. FIRE PROTECTION SYSTEM ......................................................................121


17.1.1. Fire Water System ....................................................................................... 122

17.1.2. Hydrant System ........................................................................................... 122

17.1.3. Spray Water System.................................................................................... 123

17.1.4. Portable & Mobile Fire Extinguishers........................................................... 124

17.1.5. Fire Detection & Alarm System.................................................................... 124

18. CRANES AND HOISTS.................................................................................125

19. ELEVATORS.................................................................................................127


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21.12. EFFLUENT ...............................................................................................137

21.13. SERVICE AND POTABLE WATER PIPE LINE...................................................138

21.14. CONDENSER COOLING WATER PIPING ........................................................138

21.15. AUXILIARY COOLING WATER PIPING ...........................................................138

21.16. FIRE WATER PIPING .................................................................................13821.17. VALVES...................................................................................................138

21.17.1. Insulation .................................................................................................. 139

21.17.2. Pipe Supports and Hangers...................................................................... 139

21.17.2.1. Constant Spring Hangers.......................................................................................139

21.17.2.2. Variable Spring Hangers ........................................................................................140

21.17.2.3. Rod Hangers ..........................................................................................................140

21.17.2.4. Pipe Clamps and Shoe / Saddle supports .............................................................140

21.17.2.5. Materials of Construction .......................................................................................140

21.18. GENERAL GUIDELINES FOR PIPING............................................................140

22. ANNEXURES ................................................................................................142


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1. INTRODUCTION

This document aims at establishing the criteria for basic and detail

engineering, sizing and specifications of the Power Plant equipment, systems,

components, and piping for the 2 x 60 MW Power Plant at Choudwar in Cuttack

district, Odisha, being set up by M/s. Indian Metals & Ferro Alloys (IMFA) Limited.

The basic design inputs like Fuel analysis, Water analysis, Site conditions,

etc. have been spelt out in various sections of this document, which are as per

IMFA inputs. Details developed in this document is generally in line with theagreed contract document.

This document is to be read in conjunction with design basis report for

Electrical Systems, Civil Works and Instrumentation systems. For an overall

understanding of the plant and design of auxiliary equipments and system, certain

d t il f j i t lik b il t t bi t h b i t d


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2. UNITS OF MEASUREMENT & ABBREVIATIONS

2.1. UNITS OF MEASUREMENT

Deg.C Degree Celsius

kg/cm2 (a) or Ata Kilograms per Square Centimetre (Absolute)

kg/cm2 (g) Kilograms per Square Centimetre (Gauge)

kV Kilo Volt

kW Kilo Watt

MLC Meters of Liquid Column

MW Mega Watt

MWC Meters of Water Column


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LP Low Pressure

MB Mixed Bed

MCW Main Cooling Water System (for Condenser)

MOC Material of Construction

MSL Mean Sea Level

PRDS Pressure Reducing & De-superheating Station

PRV Pressure Reducing Valve

Re Reynolds Number

RL Reference Level

RO Reverse Osmosis

SAC Strong Acid Cation


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Bureau of Indian Standards (BIS)

International Electro-technical Commission (IEC)

DIN Standards

British Standards (BS)

American Society of Mechanical Engineers (ASME)

American Society of Testing and Materials (ASTM)

American Welding Society (AWS)

American Institute of Steel Construction (AISC)

American Water Works Association (AWWA)

American National Standard Institute (ANSI)

Architecture Institute of Japan (AIJ)


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Standards of Manufacturer Standardization Society (MSS)

Indian Electricity Act

Indian Electricity Rule

Indian Factory Act & State Factory Act

Instrument Society of America (ISA)

Federal Occupational Safety and Health Organization (OSHA)

Loss Prevention Association of India (LPA)

Emission regulations of Central Pollution Control Board, India

Central Board of Irrigation and Power (CBIP) publications, India

Pollution Control Regulations of Dept. of Environment, Govt. of India

Permissible limits for pollutants of Orissa Pollution Control Board


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reliability.

4. POWER PLANT CONFIGURATION

4.1. PLANT CONFIGURATION

The power plant consists of the following major Mechanical systems and

equipment:

Two (2) number Boilers: Circulating Fluidized Bed Combustion (CFBC)

type, each generating 240 TPH at 101 kg/cm2 (a) pressure and 540 +

5oC temperature at the Main Steam Stop Valve using fuel as per Coal

Analysis mentioned elsewhere in this document. The boiler envisage de-

sulphuring using lime stone as per lime stone analysis mentioned

elsewhere in this document.

Two (2) number Electro Static Precipitator (ESP), one each per


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Regenerative feed heating system consists of two LP heater, one

Deaerator, two HP heater.

Turbine bypass system Capacity 60% of TMCR.

Boiler feed water pumping system with 3 x 100 % Motor driven boiler

feed water pumps. Out of these three pumps, one will be operating

normally for each boiler unit while the third pump shall remain as a

common standby and will come into operation automatically in case one

of the working pump fails.

One Main Cooling Tower for both units with 7 cells (6 working & 1

standby) induced draft counter flow design and RCC / Pultruded FRP

construction and main cooling water pumping system.

One Auxiliary Cooling Tower for both units with 2 cells (1 working & 1

standby) induced draft counter flow design and FRP / Pultruded FRP


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CW treatment plant, potable and service water system and effluent

system.

Compressed air system consists of plant air compressors and Air

drying plant for instrument air and service air compressors for service

air.

Ai r condit ioning &Venti lat ion system.

Fire protection system for the power plant, transformer area, fuel oil

area, switch yard area, coal handling area and ash handling area.

Inter-connecting piping system

EOT crane for TG building and miscellaneous hoists and monorails.

Elevators for Boiler and Power House building.


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Sr.No.

Item Description

1. Project Title 2 X 60 MW Thermal power project

2. Location Choudwar, Distt. Cuttack, State ofOrissa.

Longitude: 8554 E

Latitude: 2031 N

3. Nearest Town Choudwar: 0 KMs, Cuttack: 12 KMs

4. Nearest City Cuttack 12 KMs.

5. Nearest Port Paradeep

6. Nearest Railway Station Charbatia 12 km away


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Sr.No.

Item Description

g. Type of atmosphere Hot and Sultry

h. Annual Mean WindVelocity

6.4 Km/hr

i. Maximum Wind velocity As per IS 875 Part III

j. Basic wind speed As per IS 875 Part III

k. Design Wind velocity As per IS code specific to the sitelocation Choudwar, Cuttack

l. Wind Direction South to North.

m. Seismic Data As per IS : 1893 (Latest Issue)

4.3.2. COALANALYSIS


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TOTAL 100.00 100.00 100.00

GCV (Kcal/Kg) 3280.00 2010.00 2645.00

PROXIMATE ANALYSIS

Ash 42.00 60.00 51.00

Volatile matter 21.00 14.00 17.50

Moisture 15.00 13.00 14.00

Fixed carbon 22.00 13.00 17.50

Total 100.00 100.00 100.00

COAL SIZE

Feed Coal size at Grizzly of GroundHopper by Customer

90 % below 100 mm.


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Titanium as TiO2 1-2 2.32

Total carbonates as CO3 - < 0.01

Manganese oxide as

Mn3O4/MnO0.02-0.04 0.12

Zinc as ZnO - 0.02

Loss on ignition - 2.11

4.3.4. LIME STONEANALYSIS

COMPONENT % BY WT. (RANGE)

LIME STONE ANALYSIS

CaCO3 90 94% for operability. Forguaranteed sulphur capture onperformance fuel to restrict chimneyheight to 44 m, CaCO3 content shall


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TiO2 % 1.5 1.7

MnO % Traces

CaO % 0.5 0.6

MgO % 0.2 0.25

P2O5 % Less than 0.1

Na2O % Less than 0.22

K2O % Less than 0.45

BED MATERIAL SIZE

Size in Microns Unit % Passing

< 500 % 100


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8. Bi- Carbonates mg/l as CaCO3 52 60

9. Total Anions mg/l 72 89

10. Iron as Fe mg/l as CaCO3 0.8 1.0

11. Silica (Reactive) mg/l as SiO2 8.0 10

12. M- Alkalinity mg/l as CaCO3 52 60

13. Turbidity NTU 184 200

14. Total Suspended Solids mg/l 170 190

15. Total Dissolved Solids mg/l 70 80

16. pH value at 25oC 7.6 7.8

17. Conductivity at 25oC S/cm 137 150


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Convenience of fuel intake.

Convenience of Installation.

Minimum width of clear access around equipment shall be provided as 1

m.

Minimum clear height between two consecutive floors shall be determined

considering maintenance, lifting and safety requirements. A clear head

room of 2 m shall be maintained between floors and over head piping /

cabling.

All road crossing for pipe / cable rack shall be done with minimum 5.5 m

head room from top of road to bottom of rack where only Truck movement

is expected and 7.0 m where crane movement is expected. Minimum 8 m

clearance shall be kept in case of railway track with overhead traction.

Similarly top cover over any underground pipe / cable shall be minimum 1


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c) Cooling tower

d) Compressor room

f) DG room

5.1.1. POWER HOUSE

The Power House will include:

Steam Turbine Generator & auxiliaries which includes condenser, CEPs,

LP & HP heaters, Deaerator, BFPs, steam jet ejectors, gland steam condenser etc.

located in the Steam Turbine Hall.

Power house building size shall be 87 m x 31.5 m devided into AB bay

(20.5 m wide) & BC bay (11 m wide). AB bay shall have 3 floor elevations i.e.

ground floor at 0 m, mezzanine floor at 4.5 m & operating floor at 10 m. BC bay

shall have 4 floor elevations i.e. cable spreader floor at 0 m, swithgear floor at 4.0


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5. The crane rails elevation of the turbine hall shall be selected based on

turbine height and crane clearance required above turbine.

6. The vertical can type Condensate Extraction Pump will be located adjacent

to the Condenser on the ground floor.

7. The Lube Oil System will be located at mezzanine floor (4.5 m) level on

turbine side.

8. The Deaerator will be mounted on the roof of the control building i.e. at

Deaerator floor level (15 m). The Deaerator foundation design will take into

consideration any possible vibration due to steam chugging.

9. The boiler feed pumps shall be located within the power house at ground

floor (0 m). Vertical HP & LP heaters are also located on ground floor.

10. A mezzanine floor (4.5 m) would be provided to accommodate STG

auxiliaries like Gland Steam Condenser & Steam Jet Air Ejector.


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provided with necessary aviation lighting, lightning-protection, sampling ports with

platforms etc.

Adequate platform and staircase will be provided for boiler to access

different floor levels and equipment / valves / instruments of boiler for operation

and maintenance.

Both the boiler will be suitably connected through galleries at three different

levels.

5.1.3. COOLING TOWERAREA

Cooling tower area consists of Main Cooling Tower (MCT), Auxiliary

Cooling Tower (ACT), Main & Auxiliary cooling water pump house, MCC & control

room and chlorine dioxide generator room.

The MCT shall be of RCC / Pultruded FRP construction & ACT shall be of


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The inclination angle for coal conveyor will be 14 maximum. Central

walkway of 1000 mm and side walkways of 800 mm with 2.7 m clear height will be

provided along the belt conveyor gantry. A separate MCC cum control room for

coal handling plant will be provided near the crusher house.

5.3. WATER SYSTEM AREA

5.3.1. RAW WATER RESERVOIR

Raw Water Reservoir shall be developed in designated area for collection

and storage of raw water. Reservoir shall be a cut and fill arrangement withsuitable embankment around this area upto a height required to build the 10,000

m3 capacity of the reservoir. Reservoir shall have two (2) compartments so that

one half can be emptied and maintained without disturbing the plant operation.

Design and construction of the reservoir shall be done in such a fashion that no

water can escape from the reservoir through seepage.


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5.4. SWITCHYARD AREA

The 132 kV switchyard & 33 kV switchyard are located on west end side of

the plant so that HT line from the generator transformer can be conveniently

interconnected.

5.5. ASH SILO AREA

Bed & Fly ash silos of RCC construction are provided eastern side of the

plant near to the plant boundary & away form main plant area to avoid the dust

nuisance while discharging to the open truck.

5.6. MISCELLANEOUS

The interconnection pipe work between plant utilities and power block

equipment will be routed through pipe racks / sleepers and pipe trenches

depending on the layout. The Main Cooling water and Auxiliary Cooling water


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6.2. TURBINE

The Steam Turbine will be of horizontal, single casing impulse-reaction with

axial flow multistage construction. The Turbine will be designed with five bleeds,

for the regenerative heating requirement in LP Heater, Deaerator and HP Heater.

Steam Turbine Casings & Admiss ion Valves

The turbine casing is horizontally split. The upper and lower casing halves

are flanged and assembled by bolts. Steam flow through the turbine is in the axial

direction. After leaving the body of the emergency stop valve, the live steam

enters the valve chest with the control valves which forms an integral casting with

the upper half of the outer casing. The valve chest is designed as a transverse

tube with openings at both ends for assembly.

The turbine casing is divided into an admission and an exhaust section.

Depending on the initial steam conditions, the admission sections of comparable


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The guide blades are manufactured from drawn bar material and have

pronged roots. The guide blade tips are fitted with riveted shroud strips.

Bearings

By its brackets, the outer casing is supported on the two bearing pedestals

independently from the bearing housings. The vertical position of the outer casing

is determined by adjustable positioning elements located between the brackets

and the supporting plane of the pedestals. The clearance left between the

underside of the assembly-bolt head and the bracket allows for both axial and

lateral expansion of the outer casing with respect to the pedestal. The central

position is ensured by guideways in the bottom half of the casing. They leave the

casing free to expand also in the vertical direction. The fixed reference position of

the casing is at the rear end support brackets. The casing is thus free to yield to

thermal expansion by moving forward on special slide elements between the front-

end brackets and the front bearing pedestal. The turbine rotor is supported in the


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multiple segments that would be pushed in the working position by the flat springs

and by the steam pressure. The stator labyrinth rings segments can be pushed

away from the rotor in case of accidental contact and the rubbing of rotating and

stationary parts can be minimised. The shaft shall have in the gland sections

caulked sheet fins that together with the stator collars form the small chambers of

the labyrinth gland.

During normal operation, the source of sealing steam is from the turbine

itself. During start-up and low loads, an alternative source of sealing steam is

provided from the main steam.The front outer gland shall be fed from a pressure-

control valve, which shall receive the steam from the main steam line. The rear

outer gland seals during the normal operation permanently face the vacuum inside

of the turbine casing and must be therefore continuously fed by the steam. The

feeding steam shall be taken from the front gland leakage. The leakage steam

from outer labyrinths shall go to the Gland Steam Condenser (GSC). The gland


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extraction steam lines before the QCNRV connection are connected to condenser.

The downstream of QCNRV, the drains are connected to atmospheric flash tank

and taken out. Vacuum drains are connected to a manifold in the flash tank whose

top nozzle is connected to steam space of the Condenser and bottom nozzle

connected to the hotwell. The high pressure drain is connected farthest from the

condenser, where as the low pressure drains are connected closer to the

condenser. The drain manifold connection will be above the maximum level in the

condenser hotwell.

6.5. TURBINE LUBE OIL SYSTEM

6.5.1. OIL STORAGE TANKS

Each turbine will have one (1) main oil tank designed considering the

complete drain oil from lube oil system & control oil system. The capacity of the

main oil tank is about 14 m3. The main oil tank will be provided with necessary


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6.5.3. OIL PUMPS

6.5.3.1. Main & Auxiliary Lube Oil Pump

Total three (3) pumps of identical capacity i.e. 3 x 100 % have been

provided, each one capable of meeting the total lube oil requirement. One of thesepumps is designated as Main Oil Pump (MOP) and other two as Auxiliary Oil

Pump (AOP). All the three pumps are AC motor driven.

6.5.3.2. Emergency Oil Pump

The turbine will be provided with an emergency oil pump, mounted on top

of oil tank, driven by an AC & DC motor. It will cater to the needs of bearings of

turbine, gearbox and alternator in case of failure of AC motor driven auxiliary lube

oil pump.

6.5.3.3. Overhead Tank


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escaping oil.

6.5.6. LUBE OIL PURIFIER

An oil purifier will be provided with necessary filters and heater, including

the pump and motors of the purifier system. The purifier is an off-line equipmentmeant to clean the oil in the system by partial recirculation (operated for one shift

per day). Desludging of the purifier shall be done manually periodically. The

system will purify the re-circulating lubricating oil from entrained moisture &

suspended solids. The purifier capacity will be 2000 LPM.

6.6. JACKING OIL PUMP

The turbine will have a 1 x 100 % AC motor driven and 1 x 100 % DC motor

driven jacking oil pump for turbine and generator shaft lifting during starting,

designed so as to lift the rotor from standstill condition.


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516 Gr.70) construction. The condenser will be designed with 85% cleanliness

factor. The hot well storage capacity will be minimum 3 minutes between normal

and low level at MCR condition.

6.9. MAIN TECHNICAL PARAMETERS OF STEAM TURBINE

(A) At 100 % TMCR Condition

Parameter Unit Value

Power at generator terminal kW 60,000

Main Steam Pressure at Turbine inlet Ata 98

Main Steam Temperature at Turbine inlet OC 535

Main Steam Flow at Turbine inlet TPH 224

Main steam requirement for auxiliaries TPH 0.5

Exhaust steam pressure Ata 0.1


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Main Steam Flow at Turbine inlet TPH 219



Exhaust flow TPH 166.33

(D) At Both HP Heaters out Condi tion





Main Steam Flow at Turbine inlet TPH 210.6


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(F) At 80 % TMCR Condition





Main Steam Flow at Turbine inlet TPH 180.8



Exhaust flow TPH 132

(G) At 50 % TMCR Condi tion




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Sl.No.

Parameters Unit Value

1.0 Capacity

1.1Maximum Continuous Rating [BMCR]

at main steam stop valveTPH 240

2.0 Pressure

2.1Steam Pressure at main steam Stopvalve outlet

Kg/cm2(a) 101

3.0 Temperature

3.1 Steam temperature at main steamStop valve outlet.

C 540 5

3.2Steam temp. control range for designperformance fuel

% MCR 60% MCR -100% MCR

3.3Feed water temperature at Deaeratoroutlet

C 158


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3. 100 % Washery rejects.

The boiler is designed and manufactured as per Indian Boiler Regulations

(IBR) codes. All the requirement of IBR will be taken care for safe operation of

boiler. The pressure part materials will be as per IBR codes and standard. Piping

design will be as per IBR / ASME B31.1 (latest addition). The calculations of all

pressure parts will be submitted to the Chief Inspector of Boilers for their approval.

Major boiler parts can be described as Pressure retaining parts (steam and

water circuit), Bunker and fuel feeding equipments, Air-preheater and air ducting

component, Flue gas system, Boiler supporting structure and platforms, Hoppersand fly ash system.

The complete furnace section will be of fusion welded wall type arranged as

a gas and pressure tight envelope. The circulation system will be complete with

the necessary number of down comers, supply and riser tubes piping. Steam


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pressure. The boiler is provided with necessary access platform, galleries and

stair case to approach all equipments and pressure part. The boiler top is well

enclosed by canopy with side sheeting / lovers up to drum level. The required

structural supporting steelwork for the boiler, galleries, staircases and outer casing

will be provided for the boiler, auxiliaries, ducting etc.

The boiler has been provided with three storage bunkers for application of

coal (as a main fuel), lime stone (an additive) and bed material.

The fuel feeding system will consist of drag chain feeders and fuel feed

lines. The fluidised bed is located at the bottom most part of the furnace.

The boiler will be provided with two nos. (2 x 60% MCR) ID, SA and PA

fans and the complete air and gas ducting with required dampers and expansion

joints. All the fans will be provided with variable speed fluid coupling.

The feed water system will consist of three (3) nos (3 x 100 %) motor


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7.2.2. STEAM DRUM

Steam drum will be of welded construction, completely radiographed to

prove weld soundness, stress relieved and hydraulically tested. The boiler quality

plate for the drums will be fabricated to the appropriate specification and

constructed in accordance with the codes and regulations of Indian Boiler

Regulations.

Drum will be provided with suitable hemispherical dished ends and

manholes, each with a swing type cover opening internally.

The steam drum will be of fusion welded construction, with material

specification conforming to SA 516 Gr. 70. The steam drum will have nozzles for

saturated steam supply pipes to Primary super heater inlet headers, Feed water

inlet piping from economiser, water level gauges, pressure gauges, continuous

blow-down and intermittent blow down, chemical injection, sampling, air vent etc.


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Beams are supported by bolts through water cooled roof.

7.2.3.2. Divisional Wall

Divisional wall is placed in the furnace. Divisional wall is of carbon steel

construction and is a water cooled part of the boilers. This is located in the furnace

and helps is achieving / maintaining the combustor temperature.

7.2.3.3. Headers

The headers will be of adequate size and design in accordance with Indian

Boiler Regulations, and the material specification will conform to SA 106

Gr. B / SA 335 Gr. P11 / SA 335 Gr. P22 depending on the fluid temperature. The

necessary drain connections and hand-holes will be provided as required.

The connections to the steam drum and the connections to the headers will

be designed so as to form an integral circuit providing adequate natural circulation

under all operating conditions



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water line before the feed water control station.

7.2.6. ECONOMISER

The economiser will be made of bare carbon steel tubes conforming to SA

210 Gr A1 seamless and of continuous inline type with inlet and outlet headers. Itwill be supported in a structural steel frame and enclosed within welded steel

casing. Doors will be provided for observation and also access for maintenance.

The economiser will be of non-steaming type. Temperature of economiser shall

always below the saturated steam temperature.

Necessary drains, vents, temperature, pressure gauges, etc. shall be

furnished as per Indian Boiler Regulation requirement.

7.3. BOILER PERFORMANCE DATA

7.3.1. PRESSURE PART DETAILS



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Tube OD mm 44.45

Tube thickness mmAs per IBR calculation.

Min. 4.06

Tube material SA213 GR. T22 / SA213GR. T11 / SA210 GR. A1

Header size NB 200 / 250

Header thickness mmAs per IBR code

calculation.

Header material SA 106 GR.B / SA 335GR. P11

Secondary Superheater

Descript ion Unit Value



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Tube material SA210 GR. A1

Header size NB 200

Header thickness mm As per IBR calculation.

Header material SA 106 GR.B

At temperator

Descript ion Unit Value

Header size NB 200 / 250

Header thickness mm As per IBR calculation.

Header material SA106 GR.B

Risers



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2 Economiser m2 3561

3 Airpreheater ( PA + SA ) m2 10003

4Furnace (water walls +enclosure walls + divisionalwalls etc.)

m2 1441

7.3.3. TEMPERATURE GRADIENT

Sl. No. Description Unit Value

1 Combustion air side

1.1 Air pre heater In Deg. C 35

1.2 Air pre heater out Deg. C 140-150

2 Flue gas temperatures

2.1 Super heater In Deg. C 800-820



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3.8 Sec. Super heater Out Deg. C 535-555

3.9 Spray water temperature Deg. C 220-230

4 Feed water temperature

4.1 Economizer In Deg. C 220-230

4.2 Economizer out Deg. C 290-310

7.3.4. PRESSURE GRADIENT


1 Steam / water side pressure drop

1.1 Sec superheater Kg/cm2 4.6

1.2 Pri superheater Kg/cm2 0.95



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1.4 Airpreheater m/s 11-13

2 Air

2.1 Airpreheater m/s 10-12

7.3.6. SAFETY VALVE DETAILS

7.3.6.1. Safety Valve Set Pressures


1

1stdrum safety valve set

pressure Kg/cm2 (g) 119

2 2nddrum safety valve setpressure

Kg/cm2 (g) 120

3Superheater safety valveset pressure

Kg/cm2 (g) 108



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1.2 ROM coal Kg/hr 51564

1.3 Washery rejects Kg/hr 88746

2 Limestone

2.1 Performance fuel case Kg/hr 4030

2.2 ROM coal Kg/hr 3430

2.3 Washery rejects Kg/hr 4780

3 Bed material Kg/hr Nil

7.4. BOILER MOUNTINGS AND FITTINGS

The Boiler will be provided with a complete set of mountings and fittings in

accordance with the Indian Boiler Regulations, for the safe operation of the Boiler

and the details of the mountings and fittings including:



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7.4.4. SUPERHEATER

-Safety valve (secondary outlet)

-Motor operated main steam stop valve with integral by-pass valve

-Steam outlet check valve

-Start-up vent will be sized for 30% of BMCR capacity.

-Pressure gauges with isolation valves and drain valves

-Sampling valves

-Drain valves

-Air vent valves

-Valves for pressure transmitters and flow transmitters

-Main steam flow nozzle

-Thermocouples

7.4.5. SPRAY WATER LINE



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100 % ROM Coal.

100 % Washery rejects.

7.5.1. FUEL BUNKER

Each boiler will be provided with following bunker of mild steel construction.

Fuel bunker 1600 m3

Lime stone silo 120 m3

Bed material silo 80 m3

Fuel Bunker sizing basis

Sl.No.

Description Basis ofDesign

Consumptionof Material perBoi ler, TPH

BunkerCapacityRequired,m3

BunkerVolumeProvided,m3

a) Fuel bunker 50 % WasheryRejects + 50

Consumption offuel at 100%

64.42 TPHx 16 Hrs /

1600 m3(Bunker



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For each boiler there are separate bunkers. Fuel is fed into drag chain

feeder. The drag chain feeder speed is controlled through VFD. The outlet of drag

chain feeder is connected to the furnace.

7.5.3. FLUIDIZED BED

The fluidised bed will consist of compartments (sections). Each

compartment will be provided with stainless steel fuel feeding nozzles and

adequate number of stainless steel fluidizing air nozzles fitted on to the distributor

plate.

7.6. OIL FIRING SYSTEM

Three (3) nos. of burners will be installed in the front side of the furnace

panel. Burner will be used for start-up of the boiler. Burner support will be required

till 20% of boiler loading. Each Burner will be 1500 litre capacity and combined



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guard. The impeller is provided with tip liners and dynamically

balanced. ID fan will be with inlet damper (multilouver) control. ID fan

shall be with variable speed fluid coupling.

Two (2) Secondary Air (SA) fan of 60% boiler MCR capacity supplying

the necessary amount of combustion air for fluidised bed combustion of

the different fuels with sufficient pressure to overcome the resistance of

ducts, measuring devices, dampers, fluidising air nozzles, air heater

and burners. The SA fan is centrifugal type with suitably sized impeller.

The fan impeller shall be dynamically balanced and is complete with

inspection door, foundation bolts and guard. The SA fan shall be

provided with silencer to meet the noise level. The control shall be

through Inlet Guide vane. SA fan shall be with variable speed fluid

coupling.

Two (2) Primary Air (PA) fan of 60% boiler MCR capacity boosting hot



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d) Ambient temp. C 50 35 35 35

e) Back end temp. C 160 140 140 140

f) ID fan gas Qty kg/s 56.42 52.27 56.42 49.46

g)Margin onCapacity

% 20

h) ID fan Capacity kg/s 67.7

II) Head Details

a) dP SH mmWC 15 12 15 12

b) dP economiser mmWC 20 17 20 15

c) dP APH mmWC 60 50 60 44

d) dP ESP + MDC+ U Beam

mmWC 140 117 140 101

e)dP Ducts +Dampers

mmWC 25 21 25 20

f) Chi WC 10 8 10 8



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h) SA fan Capacity kg/s 19.78

II) Head Details

a) dP Bed mmWC 430 430 388 421

b) dP flowmeasuring +OFA + Duct andDamper +Silencer

mmWC 560 533 560 522

c) dP APH mmWC 50 47 50 47

d) Total dP mmWC 1040 1010 1000 990

e) Margin on head

(only on variablehead)

% 45

f) SA fan Head mmWC 1375

C) PA Fan ( 2 X 60 % MCR)



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Silencer + Ductand Damper

c) dP APH mmWC 60 54 60 53

d) dP bubble cap mmWC 400 360 400 351

e) Total dP mmWC 1585 1440 1460 1420

f) Margin on head

(only on variablehead)

% 45

g) SA fan Head mmWC 1920

7.7.2. DUCTWORK AND DAMPERS

Ducts will be sized considering a maximum velocity of 14 m/sec for air and

12 m/sec upto Air Pre-heater & 16 m/sec after Air Pre-heater for flue gas

applications. The ducts will be rectangular in cross section and will be of welded

construction, properly stiffened and reinforced. All ducts handling air and flue gas

will be fabricated with carbon steel plates of thickness not less than 5 mm for air



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7.7.3. AIR PRE-HEATER

A tubular air pre-heater is provided as the last stage of heat recovery unit.

The shell and tube side fluid shall be combustion air and flue gas respectively.

The air pre heater tubes shall be fitted into the tube sheets on both sides. Entire

Air Pre-heater shall be supported in a structural steel frame and enclosed within

welded steel casing. Air Pre-heater shall be provided with BS 6323 / 82 Part V ERW

tubes.

The clean air passes through tubes and those tubes are surrounded by hot

flue gases which help to increase the temperature of air. This hot air is used in

boiler to help combustion process.

7.7.4. ASH RECYCLE SYSTEM

Mechanical Dust Collector (MDC) is positioned in the exit of Economiser.

Th h ll t d i th MDC ill b l d th h th



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7.8. BOILER STRUCTURES AND AUXILIARIES

7.8.1. STRUCTURAL STEEL

The complete structural steel necessary to support/suspend the various

components and equipment, ducts etc. will include all auxiliary columns, duct

supporting columns, bracing, and all equipment structures etc. The structure is of

fully welded construction. Only for erection purpose, erection bolts are provided.

All structural steel will be designed for horizontal seismic forces as applicable

under the latest Revision of IS 1893 and wind forces as per latest revision of IS

875, whichever governs the design. All structural steel work will be designed as

per IS 800 and material specification conforming to IS 2062. The structure will

incorporate necessary lifting beams and hoist blocks required for maintenance of

fans, pumps etc.

7.8.2. PLATFORM,STAIRWAYS AND GRATING


P j D Ti l D N R Sh


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7.9.2. DESIGN TEMPERATURE DIFFERENTIAL -CRITERIA

The thickness of wool mattress will be calculated such that insulation

surface temperature shall remain within 65OC at an ambient temperature 35OC

with 1 m/s wind velocity. Insulation will be provided for equipment and ducts

where the temperature exceeds 60OC.

7.9.3. EXTERNAL INSULATION

The machine made mineral wool mattresses will be used as external

insulating layer and will have a uniform density of 120 kg/m3. The mineral wool

specifications and thermal conductivity figures will be as per IS: 8183.

The wire netting to be provided on both sides of mattresses will be of GI /

SS material.

7.9.4. BINDING AND STITCHING WIRE


P j t D t Titl D N R Sh t


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etc.

7.11. SAMPLING LINES

The sampling lines and sample coolers will be provided for feed water,

drum water, saturated steam and superheated steam. Sampling lines andnozzles will be of suitable material to take care of high chloride content in

circulating water.

7.12. BLOW DOWN TANKS

One (1) continuous blow down (CBD) tank and one (1) intermittent blow

down (IBD) tank of appropriate capacity, separate for each boiler, shall be

provided to receive all the continuous and intermittent blow downs and all other

drain discharges from the boilers. Necessary level control station for the

continuous blow down tank along with other fittings shall be provided.


Project Doc ment Title Doc No Re Sheet


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1 Design flue gas flow m3/sec 124 134 117

2 Flue gas temperature oC 140 140 140

3 Gas Analysis (wet)

CO2 % v./v. 13.31 12.62 13.70

H2O % v./v. 14.07 16.16 12.87

N2 % v./v. 69.54 68.20 70.32

O2 % v./v. 3.06 3.00 3.1

SO2 % v./v. 0.0064 0.0074 0.0056

4Gas density (wetbasis)

Kg/Nm3 1.2875 1.2732 1.2957

5 Dust concentration atESP inlet (wet)

gm/Nm3 70 70 70


Project Document Title Doc No Rev Sheet


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Stack emission shall be monitored to satisfy the requirements of Orissa Pollution

Control Board.

The design data for the chimney shall be as per the table below :

7.14.1. CALCULATION OF CHIMNEY HEIGHT

Sl. No. Particulars Units Value

1 Coal Consumption per Boiler Kg/Hr 64420

2 Sulphur Percentage % 0.34

3 Total Sulphur from Fuel Kg/Hr 219.0

4 Percentage Sulphur capture % 89.65 Sulphur at Stack Kg/Hr 22.7

6 SO2 From Fuel Combustion Kg/Hr 45.5

7 Stack height required m 44.0

7.14.2. CALCULATION OF CHIMNEY DIAMETER


Project Document Title Doc No Rev Sheet


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7.14.3. SKETCH OF CHIMNEY




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Following tapping point will be provided in main steam line

a. For steam jet air ejector and turbine gland auxiliary PRDS.

b. For turbine bypass system (sized for 60% TMCR flow).

c. For deaerator pegging steam line.

Suitable drain and vent connections shall be provided between

isolation valves of each boiler in line with IBR requirements. These

drain / vent isolation valves shall be manually operated.

Each boiler superheater outlet would be provided with superheater

safety valve and electromatic relief valve for over-pressure protection

of boiler superheater. Start-up vent valveof 30% BMCR flow capacity

is also provided.

(B) Auxiliary steam system for steam jet air ejector & turb ine gland

sealing steam system




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(D) MP steam system for Deaerator

From steam turbine, 3rd bleed with pressure around 6.6 kg/cm2 (a) will

be taken for deaerator. This line will be provided with pneumatic

operated quick closing non-return valve (QCNRV), normal non-return

valve and motor operated valve. Pegging steam line from main steam

will also be connected to this bleed line through a PRDS station for

pegging of deaerator during start-up and low load.

(E) LP steam system for LP heater

Two (2) nos. low pressure bleeds with pressure at around 2.5 kg/cm2

(a) & 0.735 kg/cm2 (a) will be taken for LP heaters. These lines will be

provided with pneumatic operated quick closing non-return valve

(QCNRV) and motor operated valve except low pressure line which will

be provided with normal non-return valve.




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vents shall be provided with manually operated double isolation valves.

8.1.1. CONTROL PHILOSOPHY

Steam Temperature & pressure will be maintained by combustion control

loop and attemperator in the respective boiler. The control range for temperature,

as indicated earlier, is 60 100 % for the individual boilers for 100% coal firing. In

the event of load throw-off, the main steam line pressure will tend to increase

which will activate turbine bypass control valve and excess steam (maximum 60%

of TMCR) will be bypassed to surface condenser. At the same time the

combustion control loop of boiler will also activate and once the same is stabilised

turbine bypass system will close.

8.2. FEED WATER SYSTEM

The feed water system will supply feed water to each boiler. It will also




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The deaerator-cum-storage tank unit will be complete with necessary

internal trays, water sprays, water level control system, temperature control

system, safety valve, water level indicator and alarm, access ladders and

platforms.

Chemical dosing would be performed inside the deaerator by means of

sparger pipe inside the storage tank.

Steam for heating will be supplied from the extraction of steam turbine.

Provision will also be made for supply of steam from the main steam line through

a system of pressure reducing valve and utilising flash steam from continuous

blow-down tank. The oxygen content on the outlet water will be not more than

0.007 ppm.

Details of Deaerator & Feed water storage tank is as follows.




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8.2.2. BOILER FEED PUMPS

Boiler feed water pumping system with 3 x 100% motor driven boiler feed

water pumps is provided. Out of these three pumps, one will be operating

normally for each boiler unit while the third pump shall remain as a common

standby and will come into operation automatically in case one of the working

pump fails.

Variable speed hydraulic coupling is provided to vary the speed of the feed

pump smoothly and stably over the entire range to minimise the throttling losses in

feed control valves.

Three (3) nos. motor driven boiler feed pumps with all pipe works and

valves will be supplied for the boilers. The pumps will be identical and

interchangeable. The pump will be of multistage centrifugal type, complete with

suction strainer, balance chamber and necessary suction and delivery valves,




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margin will be provided on head calculated based on 2nd drum safety valve set

pressure. With such margin, it shall be checked and ensured that even at 47.5 Hz

frequency the boiler feed water pump is capable of delivering 100 % TMCR flow

rate and required head during TMCR operation of unit. The BFP sizing basis is as

follows.

a) Pump Capacity Calculation

Feed water flow at BMCR240 TPH

As per boiler datasheet

Feed water density at 158Ctemperature

909.4 kg/m3 As per HBD

MCR volume flow 263.9 m3/hr

MCR volume flow with 3% make-up 271.8 m3/hr

Margin 10% 27.2 m3/hr

C l l d fl 299 3/h




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Suction pressure (H) 7.8 kg/cm2 (a)As per HBD &prelim. equipmentlayout

Required TDH in water column (G-H/ density)

1375 mWC

Required Rated Head (includingMargin 5%)

1444 mWC

Selected Rated Head 1495 mWC

8.2.3. HPFEED WATER HEATERS

Two (2) nos. HP heaters will be located on the down stream side of boilerfeed pumps and will be used for raising the boiler feed water temperature to

230oC. The HP heater shall be mounted vertically in the turbine house. The

heating steam for the HP heaters shall be supplied from the high pressure turbine

bleeds. The normal condensate drain from the HP heater shall cascaded back to




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% capacity pneumatically operated control valve is provided to control the feed

water flow at low load. Full load control valve shall be operated through single

element or three element control mode. Low load control valve shall be operated

in single element mode. The upstream isolation valves for the control stations are

motorised for automatic changeover.

In order to avoid excessive throttling and power loss at feed control station,

the differential pressure across feed control valves under steady state shall be

maintained at a constant value by varying hydraulic coupling of boiler feed pump.

HP heater shell side level is maintained by a control station leading the

condensate to the earlier HP heater or deaerator. In case of deaerator high level

or at low load & starting, this condensate will be diverted to the HP flash tank

through another control station.

In case of very high level in the shell, extraction steam line motorised valve




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cooled surface condenser. Drain condensate from LP heaters, GSC and inter-

after ejector condensers are taken to the flash pipe of the condenser.

8.3.1. SURFACE CONDENSER

The condenser shall condense all the steam at the steam turbine exhaust,

and shall receive all the condensate from the steam jet ejector condensers, gland

steam condenser and LP heaters. At an emergency condition of very high level in

HP heater, the condensate drain will be diverted to condenser through HP flash

tank instead of the deaerator. A flash pipe mounted near the condenser will

receive all the drains. The vent and drain from the HP flash tank and flash pipe will

be connected to the shell and hotwell of the condenser respectively.

The condenser shall be designed as per Heat Exchanger Institute (HEI)

standard for surface condensers.

The condenser shall be of horizontal two-pass type and shall be so




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maintenance. Condenser (tube side) shall be hydro-statically tested according to

the Heat Exchange Institute Standards.

Condenser water box shell shall be of carbon steel (SA 516 Gr. 70)

material. Condenser tube sheet shall be of carbon steel (SA 516 Gr. 70) material.

Suitable drain and vent connections complete with necessary valve shall be

provided for all the water boxes to obtain a smooth flow path in the water boxes

and even water distribution to the tubes and to avoid any unvented air pockets.

The condenser shall be provided with a hotwell made of carbon steel (SA

516 Gr. 70) having a total storage capacity of at least three (3) minutes of the totaldesign condensate flow (between normal and low level) at maximum steam load

condition. The hotwell shall be provided with suitable access doors. Drain valves

with blind flanges shall be provided on hotwell.

A rupture disc designed as per manufacturers standard shall be provided




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Cooling water temperature(inlet / outlet)

33 C / 42 C

Cleanliness factor 85 %

Plugging margin 3 %

Condenser heat load

(corresponding to VWOoperation)

87142367 Kcal/hr

Surface area 4900 m2

Hotwell capacity 3 minutes storage of the totaldesign condensate flow betweennormal level to low level atmaximum steam load condition

Material of Construction :

Shell Carbon steel (SA 516 Gr. 70)

Tube sheet Carbon steel (SA 516 Gr. 70)

Hot-well Carbon steel (SA 516 Gr. 70)

T b St i l t l (SS 304)




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condenser are provided. Each service air ejector is of two stages with an inter-

condenser between the Ist and IInd stage and an after-condenser located after

the IInd stage. The condensate from the inter-condenser and after-condenser is

led to the main condenser through a loop seal and trap station respectively.

Condensate from the CEP discharge passes through the tube side of the inter and

after-condensers.

The following are the brief details of the Ejectors: -

No. of ejectors Service - Two (1 W + 1 S)

Start up One (1)

Design CalculationsStandard

HEI

Location Indoor

Medium to be handledMixture of air, steam and non-condensable gases

C li M di C d t




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Condenser hotwell level is very low.

Motor is overloaded.

The standby pump will come on auto if:

Running pump trips.

Discharge header pressure drops below a predetermined value as sensed

by a pressure switch.

In order to prevent the operation of the CEP on shut off head and to ensure

minimum flow through the inter/after ejector condenser and gland steam

condenser, a minimum flow recirculation facility is provided for the CEP. This

consists of a control valve and CEP discharge flow transmitter. The recirculation

flow is routed back to the condenser hotwell.

The condensate outlet from the CEP is routed to the deaerator after



2 60 MW THERMAL


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b) Pump Head Calculation

Deaerator safety valve setpressure (A)

8 kg/cm2 (a)As per deaeratordata sheet

Pressure drop at deaeratorspray water nozzle (B)

0.75 kg/cm2As per deaeratordata sheet

Pressure drop in Piping (C) 0.4 kg/cm2As per prelim.piping layout

Pressure drop across flownozzle (D)

0.2 kg/cm2 Estimated

Pressure drop in LP heaters (E) 1.6 kg/cm2 As per LP heaterdata sheet

Pressure drop in ejectorcondenser (F)

0.5 kg/cm2 As per ejector datasheet

Pressure drop GSC (G) 0.5 kg/cm2 As per GSC data



2 60 MW THERMAL


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8.3.4. LPFEED WATER HEATERS

The LP heaters will be located on the down stream side of condensate

extraction pumps after gland steam condenser and will be used for raising the

condensate water temperature to 123C. The LP heater shall be mounted

vertically in the turbine house. The heating steam for the LP heater shall besupplied from the low pressure turbine bleeds. The normal condensate drain from

the LP heater shall be cascaded back to earlier LP heater and then to the

condenser. An emergency condensate drain of LP heater 1 is also provided

directly to the condenser flash pipe. The condensate water side of the LP heater

shall be designed to withstand the CEP shut-off pressure. The steam side of theLP heater shall be designed to suit the highest bleed steam pressure obtainable.

The condensate water outlet from LP heater will be connected to the deaerator

through level control station.



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Cooling media Condensate

8.3.6. MAKE-UP WATER

The normal DM water make up to the power cycle shall account for the loss

of water from the system due to blowdown from the boilers (considered @ 1 %normal & 3 % maximum), loss of steam from service air ejectors, deaerator losses

and leakage of water from the system. DM water from DM water storage tank will

be transferred to overhead condensate storage tank (CST) by DM water transfer

pumps. Make-up for above losses is provided in condenser hotwell through gravity

from this CST through a control valve. The control valve will be sized for 3 %make-up water requirement.

8.3.7. CONTROL PHILOSOPHY

Condenser hotwell level shall be maintained by regulating condensate flow



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9. WATER SYSTEM

9.1. PLANT WATER SYSTEM

9.1.1. RAW WATER SYSTEM &RAW WATER RESERVOIR

Water from Mahanadi river will be pumped by means of raw water intake

pumps to the raw water reservoir. The raw intake pumps and piping upto raw

water reservoir are in Owners scope. The EPC contractors scope starts from the

raw water reservoir.

Raw Water Reservoir, for collection and storage of raw water, of total

capacity 10,000 m3 in two (2) compartments along with gates and accessories

shall be provided. Inside and bottom surface shall be lined with impermeable

HDPE lining of thickness 1 mm. Design and construction of the reservoir shall be

done in such a fashion that no water can escape from the reservoir through



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9.1.2. RAW WATER PRE-TREATMENT PLANT &CLARIFIED WATER TANK

The water pre-treatment plant mainly comprises of cascade aeration cum

stilling chamber (1 x 100 %), inlet channel with parshall flume (1 x 100 %), flash

mixture (1 x 100 %), flocculation tank (1 x 100 %), Klari-tube settlers (2 x 100 %),

sludge sump (1 x 100 %) and sludge transfer pumps (2 x 100 %).

Various chemical preparation and injection systems in the raw water pre-

treatment plant shall be designed generally based on the following guidelines:

Alum : 60 ppm

Polyelectrolyte : 1 ppm

Sodium

Hypochlorite

: Equivalent to 5 ppm chlorine

Chemical house to accommodate chlorination system, storage space for

chemicals, chemical solution preparation tanks, dosing pumps, MCC, Control

Room etc and all other accessories shall be provided



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Clarified water pump house will also house fire water pumps. A dead

capacity, as per the requirement of TAC, to supply firewater in case of emergency,

will be kept below the minimum submergence level of clarified water storage tank.

The clarified water storage tank shall meet the entire water requirement of

the various power plant consumers like DM water, cooling tower make-up water,service water, potable water, fire water etc. The water balance diagram showing

the water requirement by various consumers is attached in Annexure-II.

9.1.3. MAIN COOLING TOWER MAKE-UP SYSTEM

Make-up water needs to be supplied to the main cooling tower to recover

the water lost in CT blowdown, evaporation & drift losses and SSF backwashing.

This make-up water to main cooling tower is supplied by 2 x 100 % main CT make

up pumps from the clarified water storage tank.

The main cooling water make-up requirement has been calculated as



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Capacity of pumps with 10% Margin : 380 m3/hr

9.1.4. DMFEED-CUM-AUXILIARY COOLING TOWER MAKE-UP SYSTEM

Make-up water needs to be supplied to the auxiliary cooling tower to

recover the water lost in CT blowdown and evaporation & drift losses. This make-

up water to auxiliary cooling tower is supplied by 3 x 50 % DM feed-cum-auxiliary

CT make up pumps. A tapping is taken after dual media filter header to supply a

better quality filtered water as a make-up to auxiliary cooling tower.

The auxiliary cooling water make-up requirement has been calculated as

follows:

Auxiliary cooling water requirement for the

auxiliary coolers

: 1,976 m3/hr

Cooling Range (from 40C to 33C) : 7 deg C





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potable water + filter backwash water

= 29 + 20.25 + 3 + 1.25

= 53.5 m3/hr

Number of DM feed-cum-auxiliary CT makepumps & DMF : 3 x 50 %

Capacity of DM feed-cum-auxiliary CT makepumps & DMF with 10% Margin : 30 m3/hr

9.1.5. DEMINERALIZATION WATER SYSTEM

The filtered water from DMF is fed to a DM Plant (2 x 25 m3/hr capacity) to

generate boiler quality water. A tapping is taken after duel media filters to store

filtered water in a filtered water storage tank of capacity 40 m3. Potable water (3

m3/hr) and backwashing water for DMF (1.25 m3/hr) will be fed from this filtered

water storage tank.





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Bed (MB) exchanger. Acid and alkali measuring tanks (common to both streams)

with ejectors shall form part of the system to provide these chemicals for

regeneration. Hydrochloric acid and sodium hydroxide shall be the chemicals

used for this purpose.

The DM Plant shall be designed to operate continuously for 18 hoursbefore regeneration of the exhausted resin in the ion exchangers. The

regeneration of the exchangers shall be completed in a maximum period of 6

hours. Regeneration water heater for regeneration of anion resins will be

provided.

The waste from the regenerated waste of DM plant shall be collected in

drain pits near the vessels and routed through acid/alkali proof lined trenches to a

neutralizing pit. Acid or alkali as required shall be dosed in this pit and the effluent

shall be neutralized by recirculation before being pumped to the guard pond.





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shall also be provided.

Design quality of treated water at the DM Plant outlet shall be maintained

with silica content maximum : 0.02 ppm and conductivity not to exceed 0.1

micromho/cm.

9.1.6. DMWATER DISTRIBUTION SYSTEM

DM Water from the DM water storage tanks shall be pumped by 2 x 100%

DM transfer (power cycle make-up) pumps of capacity 17 m/hr (with 10 % margin

on cycle make-up water requirement i.e. 15.4 m/hr). Power cycle make-up pumps

shall be located outdoor near the DM water storage tank. The DM water shall be

stored in the Condensate Storage Tank (CST). The CST tank shall be horizontal

cylindrical steel tank with capacity sufficient to hold 3% make-up water

requirement of two (2) hours i.e. 30 m. The tank shall be designed as per IS:803

and provided with inlet, outlet, drain, overflow and vent connections. Power cycle





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Type of pump Horizontal centrifugal

Location of pumps Near clarified water tank

Capacity of each service water tank m 1 or 2 (as required)

Selected pump capacity with margin m/hr 6

Location of tank STG Building, DM plant

building, Pre-treatmentplant building, ESPcontrol room-cum-compressor house, Ashhandling area etc.

Distribution of service water from tank By gravity

9.1.8. POTABLE WATER SYSTEM

A tapping is taken after Duel media filters to store a filtered water in a

filtered water storage tank of capacity 40 m3. The potable water treatment further

comprises of dosing with sodium hypochlorite for chlorination. Two (2) nos. pumps

f it 3 3/h h h ll b id d t t t bl t i t t



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house, Administrativebuilding, Medical building,canteen, store, workshopetc.

Distribution of potable water from potablewater tank

By gravity

9.2. COOLING WATER SYSTEM

9.2.1. MAIN COOLING WATER SYSTEM FOR CONDENSER

9.2.1.1. System Description

The main cooling water system will be used to cool the circulating water

used for condensing steam in the surface condenser.

Main cooling water system for surface condenser will be closed cycle

cooling system employing a cooling tower common for two units, cooling water

pumping system, CW treatment system and associated piping & valves.



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will be vertical turbine type pumps located in a pump house at the end of the fore

bay. There will be a total of three (3) number of CW pumps, one will be working

for each unit and the third will remain as common stand by. Overhead EOT c

design basis imfa

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