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CRESCENT POWER LIMITED

20 MW

EXTENSION PROJECT, PHASE-II

COAL WASHERY REJECT, SHALE AND JHAMA

COAL-BASED THERMAL POWER PROJECT

AT

SARISHATALI - ASANSOL

DISTRICT - BARDHAMAN

WEST BENGAL

INDIA

STUDY REPORT FOR PHASE-II EXTENSION UNIT

PREPARED BY

LAHMEYER INTERNATIONAL (INDIA) PVT. LTD.

LII-KEOE12022-00101-001 Rev-A Revised on Dec, 2013

Study Report

CPL Sarishatali 20 MW

Extension Project, Phase-II

CPL

LII-KEOE12022-00101-001 Rev-A Page i

TABLE OF CONTENTS

1. BACKGROUND AND OBJECTIVE ...............................................................1

1.1 PROJECT BACKGROUND ................................................................................1

1.2 SCOPE & OBJECTIVES OF THE STUDY..........................................................2

1.3 SITE VISIT ON 19.03.12 – SUBSEQUENT DISCUSSIONS ...............................2

2. GENERAL BACKGROUND AND SALIENT FEATURES ...........................4

2.1 SITE LOCATION AND ACCESS .......................................................................4

2.2 CLIMATE AND METEOROLOGICAL DATA ..................................................5

2.3 INPUT REQUIREMENTS ..................................................................................5

2.4 PLANT CAPACITY & AVAILABILITY .......................................................... 11

2.5 POWER OFF TAKE .......................................................................................... 11

2.6 POWER EVACUATION ................................................................................... 11

2.7 SITE SELECTION CRITERIA .......................................................................... 12

2.8 LAND ............................................................................................................... 12

2.8.1 Requirement....................................................................................................... 12

2.8.2 Availability ........................................................................................................ 12

2.9 WATER ............................................................................................................ 12

2.9.1 Cooling Water System ........................................................................................ 12

2.9.2 Selection of Type of Cooling Tower.................................................................... 12

2.10 FUELS .............................................................................................................. 13

2.10.1 Main Fuel Selection ........................................................................................... 13

2.10.2 Start-up & Flame Stabilization Fuel .................................................................. 14

2.11 ASH .................................................................................................................. 14

2.11.1 Quantity ............................................................................................................. 14

2.11.2 Utilisation and Disposal Options ....................................................................... 14

2.12 MAIN EQUIPMENT SELECTION ................................................................... 14

2.12.1 Capacity Selection of the Plant .......................................................................... 14

2.12.2 Configuration of the Proposed Plant .................................................................. 15

2.12.3 Steam Cycle Parameters .................................................................................... 15

2.12.4 Selection of SG Technology................................................................................ 16

2.12.5 Selection of Condenser ...................................................................................... 17

2.12.6 Selection of Thermodynamic Cycle .................................................................... 17

2.12.7 Equipment Sourcing ........................................................................................... 17

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LII-KEOE12022-00101-001 Rev-A Page ii

2.12.8 Power Purchase Agreement ............................................................................... 17

3 ENERGY EVACUATION PLAN ................................................................... 19

3.1 TRANSMISSION INTERCONNECTION ......................................................... 19

4. MECHANICAL EQUIPMENT AND SYSTEM................................................. 21

4.1 STEAM GENERATOR AND ACCESSORIES ............................................................... 21

4.2 MAIN FUEL UNLOADING, TRANSPORTATION AND FEEDING SYSTEM ..................... 27

4.3 ASH HANDLING SYSTEM ..................................................................................... 31

4.4 PLANT WATER SYSTEM ...................................................................................... 33

5. ELECTRICAL SYSTEM AND EQUIPMENT ................................................... 39

5.1 ELECTRICAL SYSTEM ARRANGEMENT: ................................................... 39

5.2 CONSTRUCTION POWER: ............................................................................. 41

6.0 CONTROL AND INSTRUMENTATION SYSTEM ......................................... 43

6.1 DESIGN PHILOSOPHY .......................................................................................... 43

6.2 MAJOR CONTROL AND INSTRUMENTATION SYSTEMS ........................................... 43

6.3 DISTRIBUTED CONTROL SYSTEM (DCS) .............................................................. 44

6.3.1 Close Loop and Open Loop Control System ....................................................... 45

6.3.2 Operator Interface Units (OIU) ......................................................................... 46

6.3.3 Data Communication ......................................................................................... 46

6.3.4 Historical Storage and Retrieval (HSR) System .................................................. 46

6.3.5 Performance Calculation ................................................................................... 46

6.3.6 Sequence of Event Recorder (SER)..................................................................... 46

6.3.7 Alarm Annunciation System ............................................................................... 47

6.3.8 Electrical Systems Operation and Monitoring: ................................................... 47

6.3.9 System Programming and Documentation.......................................................... 47

6.4.2 STEAM TURBINE GENERATOR (STG) CONTROL SYSTEM ...................................... 48

6.5 ALTERNATIVE PHILOSOPHY ................................................................................ 48

6.6 DCS BASED BALANCE OF PLANT OFF SITE CONTROL SYSTEM: .............................. 48

6.7 STAND ALONE BALANCE OF PLANT OFF SITE CONTROL SYSTEMS ......................... 48

6.8 TURBINE SUPERVISORY INSTRUMENTATION SYSTEM............................................ 48

6.9 VIBRATION MONITORING SYSTEMS FOR HT DRIVES ............................................ 49

6.11 CONTROL PANEL / CONTROL DESK ..................................................................... 49

6.12 CONTROL ROOM EQUIPMENTS ............................................................................ 50

6.13 MEASURING INSTRUMENTS ................................................................................. 50

6.14 STEAM AND WATER ANALYSIS SYSTEM (SWAS) ................................................ 51

6.15 STACK EMISSION MONITORING SYSTEM .............................................................. 51

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LII-KEOE12022-00101-001 Rev-A Page iii

6.16 AMBIENT AIR QUALITY MONITORING SYSTEM .................................................... 51

6.17 UNINTERRUPTIBLE POWER SUPPLY (UPS) AND DISTRIBUTION ............................. 51

6.18 FINAL CONTROL ELEMENTS ................................................................................ 52

6.19 INSTRUMENTATION & SPECIAL CABLES ............................................................... 52

6.20 MAINTENANCE AND CALIBRATION INSTRUMENTS ............................................... 52

6.21 ERECTION HARDWARE ........................................................................................ 52

7. CIVIL WORKS ................................................................................................. 54

7.1 LAND DEVELOPMENT ......................................................................................... 54

7.2 GEO-TECHNICAL INVESTIGATIONS....................................................................... 54

7.3 TOPOGRAPHICAL SURVEY ................................................................................... 55

7.4 PLANT LAYOUT .................................................................................................. 55

7.5 WATER INTAKE .................................................................................................. 55

7.6 PLANT BUILDINGS .............................................................................................. 56

7.7 PAVING AND PLINTH PROTECTION ....................................................................... 57

7.8 FOUNDATIONS .................................................................................................... 57

7.9 TRANSFORMER AREA .......................................................................................... 57

7.10 SWITCHYARD AREA ............................................................................................ 57

7.11 CHIMNEY ........................................................................................................... 57

7.12 RAW WATER RESERVOIR .................................................................................... 57

7.13 MISCELLANEOUS BUILDINGS .............................................................................. 58

7.14 SHALE, DEVOLATISED COAL (JHAMA) & WASHERY REJECT HANDLING SYSTEM .. 58

7.15 ASH HANDLING SYSTEM ..................................................................................... 60

7.16 PIPE & CABLE RACK & TRENCHES ....................................................................... 60

7.17 SEWERAGE SYSTEM ............................................................................................ 60

7.18 COOLING TOWER ................................................................................................ 60

7.19 LANDSCAPING .................................................................................................... 60

7.20 ASH UTILIZATION ............................................................................................... 60

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LII-KEOE12022-00101-001 Rev-A Page iv

LIST OF EXHIBITS

Exhibit 1 : Coal Analysis Data

Exhibit 2 : Cost comparison WCC vs. ACC

LIST OF DRAWINGS

1A. LII-KEOE12022-00110-001-WCC, RA : Plot Plan

1B. LII-KEOE12022-00110-001-ACC, RA : Plot Plan

2A. LII-KEOE12022-40021-001-1(WCC), RA : Flow Diagram for Plant Water System

2B. LII-KEOE12022-40021-001-2 (ACC), RA : Flow Diagram for Plant Water System

3. LII-KEOE12022-40121-001, RA : Flow Diagram for Coal Handling System

4. LII-KEOE12022-20522-001_ : PID For Air Cooled Condenser System

5A. LII-KEOE12022-00027-001-1_ : Water Balance Diagram – Water cooled

condenser

5B. LII-KEOE12022-00027-001-2 : Water Balance Diagram – Air cooled

condenser

ANNEXURE

1. Site feedback & discussion on inputs during site visit on 19.03.2012 and subsequent

emails.

2. CPL comments & LII responses on Draft Study Report – Dated 03/05/2012.

3. Discussions during meeting on 07/05/2012 at CESC office and subsequent LII email

dtd 06/07/2012.

4. Discussions during meeting on 25/07/2012 at CPL office

REFERENCE DOCUMENT

DETAILED PROJECT REPORT (doc. no. LII-4236-000-T-001) Dated Aug 2007 for

Phase II of the Project prepared by LII.

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SECTION – 1

BACKGROUND AND OBJECTIVE

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LII-KEOE12022-00101-001 Rev-A Page 1

1. BACKGROUND AND OBJECTIVE

Crescent Power Limited (CPL), a subsidiary of Integrated Coal Mining Ltd (ICML), a

group company of CESC Ltd (RP-SG Group Company), is engaged in generation of

Power through its Sarishatali Power Plant. CPL proposes to enhance generating

capacity of this station by utilizing additional fuel resource available from ICML and

therefore intends to undertake a technical study which is being carried out

hereinafter in this report by LII.

1.1 PROJECT BACKGROUND

Integrated Coal Mining Limited (ICML) promoted by M/s CESC Ltd, has developed a

captive coal mine block in Sarishatali, Bardhaman district, West Bengal and has

washery with capacity 1 MTPA in close proximity of Sarishatali mine, which is

supplying washery Reject and Shale in existing atmospheric fluidized bed

combustion furnaces (also known as bubbling bed combustion furnace) for the

present 1x40 MW power plant, being installed by Crescent power Ltd. (CPL) at

Sarishatali.

Currently, the waste generation in the form of shale is as high as 0.25 million ton per

annum from the mine and another 0.4 to 0.5 million ton per year of rejects from the

washery (i.e. total fuel is 0.75 MTPA), which meets the requirement for present plant.

The mine also has substantial quantity of Devolatised coal (Jhama coal) of volatile

matter content of 8-10% which has high carbon content and is not suitable for

pulverized fuel - fired boiler, but can be burnt in AFBC or CFBC boilers.

Approximately 0.4-0.5 million tons of washery reject, 0.25 million tons of shale and

0.15 million tons of fuel per annum are available from ICML mine and coal washery

for a maximum period of 15 years from now.

With the above waste coal, one additional 20 MW unit with PLF 80% at the same

site is possible. Recent development of CFBC Boiler has the capacity to burn the

fuel efficiently to produce fly ash with low percentage of unburnt coal with an

opportunity of sale ability of the fly ash to cement plant manufacturers.

In respect to the above M/s. Lahmeyer International (India) Pvt. Ltd. has been

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appointed for preparation of Study Report for Phase-II extension unit in the

designated area for future extension at the same site of CPL, with the involvement

of a proper mix of all the three types of coal (Washery Reject, Shale & Jhama) and

intention of sale of the ash to the local cement manufacturing outfits.

1.2 SCOPE & OBJECTIVES OF THE STUDY

Objective of the study is to establish the following:

1) Assessment of present feasibility of the extension unit in respect of fuel, water availability and ash disposal based on the feed back available from existing plant & mines.

2) Use of Jhama coal in Boiler, in addition to the present washery reject and shale in a proper mix.

3) Use of ash from proposed unit aiming to maximum sale-ability to local cement industry and brickfields.

4) Study of feed back from existing unit and incorporate necessary augmentation

5) Recommendation for Boiler technology

6) Study coal handling plant for use of three different type of coal.

Justification of 1x20 MW Unit (Phase-II) at the same site, where one no. 1x40 MW

unit is already under operation and many facilities will be common for both the units.

1.3 SITE VISIT ON 19.03.12 – SUBSEQUENT DISCUSSIONS

On 19.3.2012, Engineers from Lahmeyer International India visited site and

discussed with plant engineers regarding Phase-II extension (Annexure).

Subsequently dedicated meetings with exchange of observations and comments

from CPL have been held on 07-05-2012 and 25-07-2012 in order to update the

report for finalization. This report gives some recommendation based on the usage

of new fuel, boiler technology, feasibility and adaptation of air cooled condenser,

coal handling plant, plant water systems etc.

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SECTION – 2

GENERAL BACKGROUND AND SALIENT FEATURES

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2. GENERAL BACKGROUND AND SALIENT FEATURES

Crescent Power Ltd. is generating 40 MW from the existing pit head power generating

units consisting of two AFBC boilers and one steam turbine. AFBC boiler is operating on

the fuel of ‘shale’ and ‘coal washery rejects’ produced from the ICML coal mine at the

site of Sarishatali, district of Bardhaman, West Bengal.

The proposed plant will be of sub-critical steam parameters and utilize mix of Washery

reject, Shale and Jhama coal sourced from ICML mines. Jhama coal is new addition

which is also different from shale & rejects, with higher hardness and less volatile matter

but higher GCV. Raw water requirement for extension unit shall be taken from Ajoy

River similar to existing arrangement of Unit #1. Plant consumptive water requirements

will be met by treating the river water. The ash will be collected in dry form. Suitable

system for ash utilization has been conceived like selling of fly ash to cement plants and

bottom ash for road construction, filling of mine areas, etc.

Basic inputs considered are as follows:

1) Doc no LII-4236-000-T-001-R0 dated August 2007: Detail Project Report (DPR).

2) Soil Investigation Report 808 dated Sept 2006 & 0124 (SK) Jan 2012.

3) Existing drawings and documents received from site during visit/discussion dated

19.03.2012.

4) Site feed back/discussion on inputs during site visit on 19.03.2012 (Annexure).

5) Meeting with CPL & LII on 07.05.2012 and 25.07.2012

6) Coal sampling analysis report of Jhama received from CPL on 26.07.2012.

2.1 SITE LOCATION AND ACCESS

The Project is planned to be build at Sarishatali, Asansol, West Bengal. Project Site is

located at a longitude 87º03’10’’ E and latitude 23º 47’ 07’’ N at Sarishatali near Asansol

in Bardhaman District of West Bengal, India. The proposed power station site is near to

the river Ajay.

The Project site is located about 11.5 km from the National Highway (NH– 2).

The nearest Railway Station, Baraboni of Eastern Railway, is around 6 km away from

project site. No railway linkage up to the power station is considered.

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Nearest commercial airport is Kolkata, the state capital at a distance of 190 Km and Air

Base in Panagarh at a distance of 58 Km. Nearest sea port is at Kolkata, which is about

240 kms from project site.

Available infrastructure at Kolkata Port is adequate for handling the offshore equipment

including major power plant equipment (turbine, generator etc.).

However, it is envisaged that Railway carriage will be used to transport bulk, capital

equipment and materials of the power plant project. Asansol is the nearest city 13 Km

from project site. No residential colony is envisaged to be built at the plant site.

There are no major archaeological, historical or religious sites located nearby. Therefore

the project site does not offer any negative impact on the local area, rather will have a

positive impact on socio economic conditions of the habitats around it.

2.2 CLIMATE AND METEOROLOGICAL DATA

The Meteorological and Ambient conditions Data for the Project – refer DPR (2007)

Based on the meteorological data followings shall be considered:

Design ambient dry bulb temperature : 50 º C

Minimum dry bulb temperature : 7 °C

Relative Humidity : 85 %,

(At site Max. dry bulb 48 ºC, Min. dry bulb 7 ºC)

Cooling tower Performance dry bulb temperature: 35ºC, RH of 60 % and cooling water

temperature of 33ºC.

Maximum intensity of rainfall: 80 mm in 1 Hr. (Rainfalls during the months June, July,

August, September are significant)

Design wind velocity is considered 47 m/sec.

2.3 INPUT REQUIREMENTS

2.3.1 Land

The proposed 2nd unit will be installed adjacent to 1st unit at the existing designated

area. The following major facilities would be considered common for both the units -

a. Shale, Jhama (Devolatised coal) and washery reject storage system. Handling

of the same will be similar to existing system and partly common.

b. Light diesel oil system.

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c. Raw water intake pump house and reservoir.

d. DM Plant

e. 132 KV Switchyard.

The designated land area, already acquired, will also accommodate the proposed

2nd unit within its balance of plant.

The plant layout is shown in the enclosed ‘Plot Plan’ Dwg No. LII -12022-110-001.

2.3.2 Water

Presently, twelve (12) nos. bore wells have been installed to cater raw water to the

plant from bed of river Ajay. Estimated total water quantity requirement for the

proposed extension unit is as below.

Option-1 (WCC with HCSD system): 281m3/hr.

Option-2 (ACC with HCSD system): 52m3/hr

Hence another twelve (12) nos.(for option-1) / four (4) nos.(for option-2) additional

bore wells of similar capacity as existing bore wells, will be the source of water for

both the units. The river water is presently brought to the plant by pipeline. Another

250 NB pipeline will be installed in phase-II to meet additional water requirement for

both the units.

The Water Balance Diagram for the Plant as shown in drawing no. LII-KEOE12022-

40021-101-1-RA (WCC) LII-KEOE-40021-101-2-RA (ACC),

2.3.3 Main Fuel

The project will be using substantial quantity of Washery Reject, Shale and Jhama

coal as its prime fuel supported by fuel oil (LDO) as secondary fuel for the station for

boiler start-up.

Shale, washery rejects and Jhama coal as a fuel have the following intrinsic

properties and calls for necessary measures in plant design:

- High moisture in washery reject and requirement of air drying.

- Very low heat value of Shale to be supplied in irregular sizes (up to minus 300

mm).

- Low volatile matter and high calorific value of Jhama coal to be supplied in

irregular sizes (up to minus 300 mm).

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- Washery rejects shall be received in (-) 80 mm size.

Accordingly, the following features in system design need to be adopted:

- In-plant storage of 7 days would be planned for washery rejects to permit time for

natural air drying.

- For shale and Jhama coal, primary crushing to a size of (-) 80 mm would be

necessary and then stacked in stockpile for combined feeding of both the fuels to

secondary crusher, where fuel would be crushed to the desired size of (-) 6 mm.

- High erosive ash components mainly aluminum silicates and iron oxides in

Unsorted Jhama Coal may cause furnace erosion and fluidization problems. Also

Chlorine content in fuel being very high will cause high temperature corrosion in

superheater. Hence boiler manufacturers recommend not to fire Unsorted Jhama

Coal. Further it has also been recommended that the firing of sorted Jhama coal

be restricted upto 35%.due to high chlorine and erosive metal content in ash of

Jhama coal.

The typical analysis of Washery Reject, Shale and Jhama coals are shown in

Exhibit -1

Requirement of Coal for a CFBC Boiler vis-à-vis fuel flexibility

For generation of 1x 20 MW with 85% PLF coal requirement in million tones per

annum (MTPA)

The subject of coal requirement and availability has been discussed at length during

meeting on 07.05.2012 and the following two options in respect of coal availability

have been concluded for 15 years period for the proposed 1 x 20 MW extension unit

in Phase-II.

Option-1: (figures in tones)

Coal type Total Qty. Available Consumption-

Unit#1

Qty. Available – Unit #2

Shale 250000 180000 70000

Rejects 500000 (1.5mt@33%) 280000 220000

Jhama - 0 88500

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Option-2: (figures in tones)

Coal type Total Qty. Available Consumption-

Unit#1

Qty. Available–Unit #2

Shale 250000 180000 70000

Rejects 400000 (1.2mt@33%) 280000 120000

Jhama 150000 0 150000

Maximum Available Quantity for Unit #2: (figures in tones)

Coal type Max. Qty. Available

Shale 70000

Rejects 220000

Jhama 150000

Notes:

1. Based on the tentative analysis data of Jhama coal, and the mix ratio of the three

types of coal recommended by the boiler manufacturers to attain less than 2%

unburnt carbon in fly ash, desired for the sale-ability of ash, it was observed that

the boiler steaming capacity will be limited to 95 tph meaning an equivalent unit

capacity of 20MW, with a substantial leftover quantity of Jhama and Shale (ref LII

email dtd 06.07.2012).

2. Subsequently based on the discussions during meeting on 25.07.2012, where

maximum utilization of the available coal was opined by CPL, with the relaxation

on unburnt carbon in fly ash to 4% . Accordingly, the precise coal data for Jhama

based on coal sampling analysis (as received from CPL) was given to boiler

manufacturers for an update in this respect.

The following table is a consolidation of the data furnished by the boiler

manufacturers in respect of the coal availability and the corresponding unburnt

carbon percentage with proposed boiler design pressure of 89 kg/cm2, (g),

temperature 515±5º C.

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Coal Quantity Available

Guaranteed Steaming capacity TPH at 89 kg/cm²(g) & 515 ± 5

0C

TPA Single CFBC Boiler Two CFBC Boiler

Option Shale Rejects Jhama

(Sorted) Jhama (Un

Sorted)

Un burnt carbon in fly

ash TPH

Effy (indicative) *

TPH Effy

(indicative)*

A-1 70000 120000 150000

≤ 3.1%

154 87.0 77 87.0

A-2 70000 120000 150000 133 86.3 66.5 86.3

B-1 70000 220000 150000 189 86.8 94.5 86.8

B-2 70000 220000 150000 165 85.4 82.5 85.4

C-1 70000 220000 88500 159 86.7 79.5 86.7

C-2 70000 220000 88500 145 86.3 72.5 86.3

Adequacy of Source of Fuel

Coal available for 15 years from now for proposed CFBC and existing AFBC Boiler

are indicated in above table option-1 & option-2, with the mention of the maximum

dedicated quantity available for Unit #2.

Since the plant life has been considered as 25 years for financial study in the DPR

(2007), the Units will operate with ICML coal for another 15 years from now, and

thereafter need to outsource washery reject, shale & Jhama for the remaining 10

years.

Required fuel quantity for 15 years with guaranteed unburnt carbon less than

3.1% for 156 TPH (WCC) /164 TPH (ACC) Boiler for 40MW unit with 10% margin

in steaming capacity guarantee point is as below:

Jhama (sorted): 150000 TPA

Washery Reject: 220,000 TPA

Shale: 70,000 TPA

Transportation of Coal

As being done for the present 1x40 MW unit, washery rejects is supplied from the

coal washery, located within one (1) Km from the site, by conveyor. Raw coal shale

and Jhama coal will be transported by Trucks / Dumpers from the Mines to the

power plant. Same will continue for 1 x20 MW Unit #2.

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LDO, which is the start-up fuel, is being supplied by IOCL, Durgapur. Same will

continue for proposed unit-II.

2.3.4 During discussion with plant engineers, the following points have been listed for

consideration in the proposed plant:

1) Fly ash unutilised in the existing plant is not saleable due to its 9-10% unburnt

carbon. Fly ash with ≤4% unburnt carbon is saleable to cement factories as

discussed in meeting on 25.07.12. Efforts shall be made to produce fly ash with less

than 4 % unburnt carbon.

2) Existing coal handling system operates both conveyors for 12 hours in general, and

this increases during monsoon. It was suggested to design the coal handling system

with 30% moisture content for the proposed unit.

3) Existing unit bed ash is handled through scrapper conveyor (one unit under

construction) and fly ash will be handled by HCSD method (under construction).

Proposed unit should have dry ash handling system both for fly & bed ash.

Mechanised bed ash system with bed ash silo has been envisaged. Fly ash silo shall

have HCSD provision in addition to fly ash disposal system in case utilisation is

hampered.

4) Existing filter water tank is inadequate. Extension unit filter water tank capacity

should be minimum 200cum.

5) Extension unit DM water tank capacity shall be minimum 200 cum in addition to

existing 180 cum.

6) Optimisation of coal conveyor with bunker location is to be looked into.

7) During discussion CPL also requested to consider the following for extension unit:

a) Margin on Boiler (20% Unit MCR), Turbine (10% Unit MCR) capacity.

b) Additional DG set requirement

c) Soot blowing system, if CFBC

d) Air cooled condenser, if feasible.

e) TG shaft mounted MOP

f) Dearator pegging system not required

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g) DC jacking oil pump

h) 50% steam dumping provision

i) Screw compressor in IA & Ash Compressor system

Note: During study with fuel availability, Boiler margin (a above) can be achieved

up to 20% in case of water cooled condenser option while for air cooled

condenser option it will be 15%.

2.4 PLANT CAPACITY & AVAILABILITY

The steam parameters for the proposed unit, which is not identical to unit-1, have

been considered as follows:

Parameter Unit Value

Option-1-WCC Option-2-ACC

Power at Generator Terminal MW 40 40

Boiler Capacity (MCR) TPH 156 164

Steam temp. at SH outlet Deg. C 515 +/ 5 deg C 515 +/ 5 deg C

Steam pressure at SH outlet Kg/cm2 (g) 89 89

Main Steam Pressure at

Turbine Inlet

Ata 87 87

Main Steam Temperature at

Turbine Inlet

º C 510 510

Main Steam flow at Turbine

Inlet

TPH 155.3 163.5

Exhaust Steam Pressure Ata 0.12 0.22

2.5 POWER OFF TAKE

The proposed 1x20 MW (Phase-II) is planned to evacuate energy from the station of

1x 60 (40 + 20) MW, through state grid. With Shale, Jhama and Washery Rejects as

fuel, the energy production cost from the station will also be substantially low.

2.6 POWER EVACUATION

No additional outgoing line feeder bays are envisaged for evacuation of power from

the proposed 20 MW Unit. Power will be evacuated at 132 kV from the existing

feeder bays of the 132 kV switchyard of the existing 40 MW Unit.

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However, two (2) nos. additional bays, one each for Generator Transformer # GT2 &

Station Transformer #ST2 are envisaged.

2.7 SITE SELECTION CRITERIA

The proposed unit will be installed adjacent to the present unit within the same site,

where the available land area is adequate. Hence, new site selection and/or catering

to the requirements/criterion is not relevant for the project.

2.8 LAND

2.8.1 Requirement

The land for the present and proposed units is already acquired. Hence, no

additional land is required for the proposed unit.

2.8.2 Availability

The land area is adequate to meet the Plant requirements, including green belt

development.

2.9 WATER

Presently, twelve (12) nos. bore wells have been installed to cater raw water to the

plant from bed of river Ajay. Estimated total water quantity requirement for the

proposed extension unit is as below.

Option-1 (WCC with HCSD system): 281 m3/hr.

Option-2 (ACC with HCSD system): 52 m3/hr

Hence either twelve (12) nos. (for option-1) or four (4) nos. (for option-2) additional

bore well of similar capacity as existing bore wells, will be the source of water for

both the units.

2.9.1 Cooling Water System

Closed cooling water system with cooling will be envisaged to minimize the

consumptive water requirement for the plant and hence optimum drawl of water from

the river.

2.9.2 Selection of Type of Cooling Tower

DPR has already explained that Air cooled condenser will cause for high investment

but the requirement of plant water is less than water cooled condenser. Space for

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both the options water cooled condenser & air cooled condenser are available as

shown in respective plot plan drawings. Adaptation of specific option between WCC

and ACC shall have to be selected before finalization of the specification. The ACC

system design has been considered based on ambient temperature of 42 deg C.

Accordingly, during the extreme summer with higher ambient temperature, the plant

capacity will be reduced.

2.10 FUELS

The plant has been identified for firing of Shale, Jhama and Washery Reject coals.

Hence the primary fuel of the plant for power generation is coal in mix of three

ingredients namely, Washery Rejects (50%), Shale (16%) & Jhama (34%).

2.10.1 Main Fuel Selection

Integrated Coal Mining Limited (ICML) promoted by M/s CESC Ltd, has developed a

captive coal mine block in Sarishatali, Bardhaman district, West Bengal, for the

purpose of supplying coal to the thermal power station. ICML has installed washery

plant and use rejects for the existing plant.

The mine also has substantial quantity of Jhama coal (heat affected coal) of volatile

matter content of 8-10% but has high carbon content.

Such inferior quality of fuel available at this rate, however, can be burnt in

atmospheric fluidized bed combustion furnaces (also known as bubbling bed

combustion furnace) and Circulating Fluidized Boiler efficiently. Depending upon the

process deployed, moderately high combustion efficiency can be attained in such

furnace. Steam generation by deploying AFBC combustion process can attain an

efficiency figure of 80% and by CFBC the same can be attained 82 to 87%.

Thus, with utilization of Shale, Jhama and Washery Reject coals, the energy cost

from the station using CFBC Boiler will be considerably lower.

The expected coal quality is enclosed as Exhibit No. 1.

Boiler efficiency for the desired mix of coal is as below:

34% Jhama (sorted) + 16% Shaly coal + 50% Washery Rejects: 86.8%

Before finalization of the specification, a proper coal sampling of Jhama, Washery

Reject and Shale and analysis indicating GCV, HGI, Sieve Analysis, density,

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proximate and ultimate analysis on as received basis is to be done for submission to

Boiler manufacturer for accurate design of the Boiler.

2.10.2 Start-up & Flame Stabilization Fuel

LDO shall be used for Cold Boiler start up only.

2.11 ASH

2.11.1 Quantity

Considering an ash content of about 65%, the estimated maximum ash generation in

the plant is approximately 39 TPH for proposed CFB Boiler.

2.11.2 Utilisation and Disposal Options

As per the MOEF notification dtd 14.09.1999, a new coal based power station should

make plans for utilization of 100% fly ash, in phased manner, within 9 years of

commissioning.

Being located close to the mine, ash generated from the station is proposed to fill-up

the mine progressively. Moreover, there are number of cement industries and

brickfields in the vicinity who would be interested in obtaining ash from the station.

Considering the above mode of disposal of bed ash as mine fill and fly ash usage in

other industries, no land would be procured for ash disposal from the station. Thus

100% utilization of ash will be achieved. To achieve the utilization, unburnt carbon in

the fly ash is to be reduced to less than 4% to ensure sale ability for cement plants.

Boiler manufacturers have to guarantee this fly ash quality. Bed ash is to be used in

roads & mine filling.

2.12 MAIN EQUIPMENT SELECTION

2.12.1 Capacity Selection of the Plant

The station is presently receiving Shale from Sarishatali mine to the tune of 0.25

MTPA and Washery Rejects from ICML’s washery @ 0.5 MTPA. This caters to the

present 1x40 MW unit at a load factor of 80%.

Approximately 0.25 MTPA of shale, 0.4-0.5 MTPA of washery reject and 0.15MTPA

of Jhama are available from ICML mines for another 15 years from now. With the

available fuel mixing of jhama, washery reject and shale the unit can generate steam

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in the range of 189 TPH, 515 ºC and 89 ata which is a suitable match for a 40MW

steam turbine.

As gathered from the discussion with Boiler manufacturers, the optimum choice is to

adopt CFBC Boiler as against AFBC due to the following;

a) To limit the unburnt carbon in fly ash to a figure of ≤4% which is needed for its

sale ability / commercial value.

b) Inherent advantage of CFBC Boiler with respect to efficiency, scale of

economics, superior combustion technology and reliability.

CFBC Boiler in the range of 150 to 180 TPH single boiler is in operation in India for

more than 20 years and it is proven by BHEL, IJT, Thermax, Thyssen krupp etc.

Thus, the proposed extension plant has been selected with an installed capacity of

1x20 MW with CFBC Boiler. A detail discussion is presented cl no 2.12.4.

Jhama, Shale & washery reject requirement per year is 0.15, 0.07 & 0.22 MTPA

respectively, for 1x 20 MW extension project, i.e. 0.44 MTPA mix of jhama, shale &

washery design coal, which has higher GCV 2271 Kcal/kg.

2.12.2 Configuration of the Proposed Plant

Configuration of the proposed plant is single 189 TPH CFBC Boiler with a single

Turbine. Two Boilers with one turbine configuration is not economically feasible, for

the following reasons:

a) Recommended by manufacturers

b) Boiler rating of 189 tph of CFBC design has become standardized and well

proven

c) Reduced auxiliary power consumption

d) Optimization of space requirement

e) Improved efficiency

f) Overall economics

2.12.3 Steam Cycle Parameters

The primary factors, which govern the steam cycle selection are - efficiency,

equipment cost and the fuel price. With higher steam parameters, the investment

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cost goes up on account of increase in the cost of SG and turbine island equipment,

but efficiency improves.

As per the present 1x40 MW Unit, the proposed unit will generally operate around 87

ata, 510 deg C main steam temperature. This steam parameter range is proven and

standard units are available with such parameters. Therefore considering optimum

cost economic aspect, the selection of the unit is in order.

Typical heat balance diagram with the above steam parameters is available in the

DPR (2007).

The heat cycle consists of a steam turbine with, condensate pumps, low-pressure

and high-pressure feed water heaters, a desecrating feed water heater, and electric

motor driven feed water pumps.

Heat rejection is accomplished by either a closed loop circulating water system

utilizing an induced draft cooling tower to supply cooling water to a condenser

operating at an absolute pressure of 0.12 Ata. Or an air cooled condenser operating

at an absolute pressure of 0.22 Ata.

2.12.4 Selection of SG Technology

Steam generators using either pulverized coal (PC) combustion technology or

Fluidized Bed Combustion (FBC) Technology are available. FBC is a mature

technology with more than 300 FBC boilers in operation world wide ranging from 5

MW to 250 MW. The FBC technology is principally of value for low grade, high ash

coals which are difficult to pulverize, and which may have variable combustion

characteristics. The advantage of fuel flexibility of FBC units made it a popular

choice for different installations.

Existing plant is running two AFBC boilers with fuel shale & washery reject.

Proposed boiler shall burn shale, reject and new fuel jhama coal which is harder but

with higher GCV. Existing unit cannot utilize ash for its higher percentage of unburnt

carbon. Proposed CFB boiler shall guarantee unburnt carbon less than 3.1%. As

discussed in previous sections, adequate Shale, Jhama coal and Washery Reject

coal will be available in nearby mines. Hence, CFBC boiler has been envisaged for

the proposed extension unit for generation of 189 TPH steam at 89 ata, 515ºC to

produce 20MW. Moreover, 1x40 MW AFBC unit is presently installed at the same

site.

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All the emissions will be maintained as per the PCB norms.

2.12.5 Selection of Condenser

Refer Sl. no. 2.9.2

2.12.6 Selection of Thermodynamic Cycle

During site visit & discussion with plant engineers, certain points like selection

criterion of boiler margin as 20% MCR, VWO margin as 10% MCR, and bypass

dumping capacity of 50% have been addressed – refer Clause 2.3.4 (7) above. All

these criteria will be finalized before preparation of specification as these are related

to cost implication only.

2.12.7 Equipment Sourcing

The existing 40MW unit has been installed on EPC basis. The proposed plant (Unit

#2) is also deliberated to be supplied, erected and commissioned on EPC basis. It is

prudent to order the same EPC contractor for the proposed unit.

2.12.8 Power Purchase Agreement

Power Purchase Agreement (PPA) is to be established between CPL and power

purchaser, for sale and purchase of the power.

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SECTION – 3

ENERGY EVACUATION PLAN

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3. ENERGY EVACUATION PLAN

3.1 TRANSMISSION INTERCONNECTION

No additional outgoing line feeder bays are envisaged for evacuation of power from

the proposed 20 MW Unit. Power will be evacuated at 132 kV from the existing

feeder bays of the 132 kV switchyard of the existing 40 MW Unit.

However, two (2) nos. additional bays, one each for Generator Transformer # GT2 &

Station Transformer #ST2 are envisaged.

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SECTION – 4

MECHANICAL EQUIPMENT AND SYSTEMS

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4. MECHANICAL EQUIPMENT AND SYSTEM

4.1 Steam Generator and Accessories

a) Steam Generator

The steam generator units proposed for the station will be semi-outdoor, natural

circulation, circulating fluidized bed furnace (CFBC) with over bed fuel feeding

system, balanced draft, single drum, dry bottom type with two-pass

configuration. Steam generating plant, complete with all auxiliaries, accessories

and controls, for supplying steam to the turbine generator set of nominal

capacity 40 MW operating on unit system with the steam generator feeding to

one TG set. CFBC boiler shall have cyclone separator or internal recirculation

arrangement of lighter unburnt particles back to fluidized bed for further

combustion. The steam generator parameter will match the TG set requirement.

Capacity of steam generating unit would be 189 TPH so as to ensure adequate

margin over the requirement of turbine at VWO condition in order to cater to (a)

auxiliary steam requirement for soot blowing operation, and also for start-up of

the future unit (optional), (b) de-rating of the steam generating units after

prolonged use. The steam generators would be designed to operate with “the

HP heaters out of service” condition (resulting in lower feed water temperature

at economiser inlet) and deliver steam to meet the turbo-generator requirement

at base load. Economiser section of the boiler would be non-steaming type with

provision for recirculation during startup, chemical cleaning etc. Superheater

section would be divided in convection and radiant zones and designed so as to

maintain rated steam temperature of 515 °C (±5°C) at the outlet over a control

range of 60% to 100% of MCR load. Main steam de-superheating station would

be provided with arrangement for spraying water tapped off from feed water

piping. The steam generator will be conservatively designed for satisfactory,

continuous and reliable operation at high efficiency with the range of shale,

washery reject and jhama coal mix expected for this station (GCV ranging

between 1800 to 2600 KCal/Kg) without any requirement of support fuel for

flame stabilization etc. within its control range. Furnace would be conservatively

designed to allow adequate residence time for the fuel to burn completely. The

design air and flue gas velocities would be carefully selected to minimize

erosion of pressure parts and other vital components. The pressure parts will be

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designed as per ISO/ASME Sec.1 and would conform to the current Indian

Boiler Regulation (IBR). The boiler furnace and flue gas passages would be

designed for low gas velocities in order to minimize erosion or slagging.

The basic parameters of steam generator are furnished in the table at the end of

this clause.

Since, maximum furnace temperature in a CFBC boiler is kept within 950 °C,

NOX generation in the Steam Generator would be low. Maximum NOX emission

from the unit is not expected to be more than 750 ppm of NOX (equivalent NO2)

including thermal NOX produced during the entire operating range of Steam

Generator.

With low sulphur content in fuel, SO2 generated from the combustion and

emitted through the flue gas would be reasonably low. We have not considered

limestone feeding due to low sulphur content in all the fuels, in similar lines with

the existing Unit/ Plant. A 100 m high stack proposed is expected to bring down

the ground level concentration of SO2 based on 24-hourly average to a

minimum.

The Steam Generator and auxiliaries will perform continuously within noise

limits as per relevant standard specification but not more than 85 dB at 1 meter

from any equipment or sub-equipment and at 1.5 meter height. .

Indicative main parameters for the Steam Generator at relevant conditions are

given in the following Table:

Table 4.1

Plant Performance Parameters

Parameter Unit Value (WCC) Value (ACC)

\Boilers per unit No. 1 1

Main Steam Flow TPH 156 164

Main Steam at SH Outlet:

a) Pressure Ata 89 89

b) Temperature ºC 510 (+/- 5) 510 (+/- 5)

Feed water inlet temp. into

Economizer °C 200 205

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To arrive at actual BMCR capacity, the following margins will be considered over

the above TMCR (to cater auxiliary steam requirement for soot blowing and

normal degradation of steam generating unit after prolong use):

• Margin available for BMCR capacity is 20% in case of water cooled

condenser option and 15% for air cooled condenser option.

The combustion chamber and coal burner system will be so designed to ensure

uniform heat absorption in the furnace and the furnace exit gas temperature

about 50ºC less than the initial deformation temperature of ash considering an

excess air amount of approximately 15-20%. The SG design will take care of the

aspect of minimum NOx emission level while designing the burner systems. Soot

blowers are not installed; however provision shall be kept for installation of soot

blowers in future.

b) Modes of Operation and Control

The SG with its auxiliary equipment is one of the principal components fixing the

dynamic capacity limits of the power plant. In order to be able to follow the

required operation regime and above all the high requirements for the support in

frequency variation, measures will be taken to ensure rapid availability after

various start-up procedures and optimum load-following capability.

The superheater outlet temperature will be kept constant within the load range

from 60 % to 100 % of SG Maximum Continuous Rating (BMCR).

For operation & control please refer Clause no 6.0

c) Steam and Feed Water System

Feed water from the feed control station will enter into steam drum for converting

into steam. Economizer will be provided in the feed water line after the feed

control station to raise the feed water temperature before feed water goes to

steam drum. The economizer outlet temperature will be kept slightly less than

saturation temperature to avoid steaming in the economizer.

Steam drum will be provided with necessary safety valves, drain and vent valves

of adequate capacity along with necessary instruments. Membrane/ panel of

water walls, riser, down comers will be provided in the SG for effective utilization

of heat flux from the furnace zone to convert feed water into steam.

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Steam produced in water walls flows from the drum to the superheater and to the

outlet header through the main steam line to the inlet connection of the high-

pressure steam turbine throttle valves. A connection for providing turbine seal

steam from the Main Steam System will be included, if required, by the turbine

manufacturer.

Main steam temperature will be controlled by two / three stage spray type

attemperators as per the standard practice of the manufacturer. The spray water

for the attemperators will be taken from the feed water circuit.

Desuperheating spray water is supplied from the feed water circuit.

Safety valves, relief vent valves, and piping are provided for system operation

and overpressure protection. The design and manufacture of the SG will conform

to IBR and ASME regulation/code.

d) Auxiliary Steam

Users of auxiliary steam include the deaerator pegging steam during start-up

operation, soot blower (optional), the turbine seal system etc.

The Auxiliary Steam System supplies reduced pressure and temperature steam

to power station steam users that do not require steam at main steam conditions.

Two low capacity Pressure Reducing and De-superheating (PRDS) are proposed

for the Unit. One PRDS will be used for SJAE steam requirement. Steam for the

same will be drawn from main steam header. This PRDS reduces the pressure

and temperature to 11kg/cm2 (a) and 350 deg C respectively. Another PRDS will

be used for Desecrator pegging steam. High pressure PRDS will be used for

Turbine bypass during load throw off condition. This will reduce the main steam

Pressure and Temperature to 6 kg/cm2 (a) and 200 deg C respectively.

e) Draft System

Draft system is envisaged to have two (2) nos. Forced/Secondary Draft (FD/SA)

fans two (2) nos. of Induced Draft (ID) fans and two (2) nos. of Primary Air (PA)

fans of matching capacity, with each fan rated for 60% of BMCR capacity. The

FD/SA fans may be of variable pitch control aerofoil or centrifugal type with

silencer at air inlet. The ID fans would be variable speed (with hydraulic device or

equivalent) backward curved blade-type. The equipment should be complete with

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lube oil, hydraulic regulations and all other accessories required for continuous

operation. All equipment would be suitable for outdoor installation.

Air pre-heaters of tubular type would be provided. Two (2) numbers each of

primary and secondary air heaters will be provided for the boiler.

f) Fuel Feed Systems

Fuel firing system will be designed to burn maximum particle size of 6 mm with

fine content (less than 1 mm size) not exceeding 40%.

Steam Generator unit would be equipped with suitable shale, Jhama coal and

washery reject mix firing arrangement comprising bunkers, positive displacement

type (e.g. drag link or scrapper) raw fuel feeders in over-bed, primary air fans,

fuel and air pipes, burners etc. as necessary. The feed control for the fuel would

be done either on manual mode or automatic mode and controlled as per the

plant load and composition of the fuel mix. Provision of feeding bed material

would be provided, comprising bed material silo, feeders (screw feeders or

equivalent) with necessary controls. The firing system would ensure load

variation from 30-100% BMCR without any stabilizing fuel. The steam generating

units will be provided with arrangement for start up by light diesel oil. After

achieving the appropriate temperature profile in the furnace design fuel would be

fed to the furnace.

g) Bed Ash Extraction System

The scheme proposes, dry extraction and disposal of bed ash via bed ash

cooler, bed ash collection hoppers, ash transmittal vessels and ash conveying

pipe upto the bed ash silo.

h) Start-up Fuel Oil System

Light Diesel Oil (LDO) will be secondary fuel used only for start-up for coal

ignition Two (2) nos. 100% capacity fuel oil pumping units are provided for the

steam generators of the existing unit. One (1) additional pump of same capacity

will be installed to augment the fuel oil system, to meet the fuel oil requirement

for the Unit #2 (Phase II).

Since, the auxiliary fuel oil requirement of AFBC boiler is quite low, the light oil

handling, storage and forwarding system would be planned as common for both

the present and proposed units. One (1) no. 30 m3 capacity storage tank along

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with pumps, strainers at suction and discharge, valves, controls, instrumentation,

drain oil tank, etc. as required is installed in Phase-I. Another tank of same

capacity will be installed in Phase-II. The oil will be supplied from the nearest

depot by road tankers.

i) Electro Static Precipitator (ESP)

Each steam generating unit would be provided with one (1) no. electrostatic

precipitator. Each precipitator will have two parallel gas paths, any of which can

be isolated for maintenance as and when required, keeping the other path in

operation. Each path will have adequate number of fields in series for collection

of fly ash. The overall efficiency of ESP should not be less than 99.99% with one

field remaining as operational standby. The ESP would have adequate number

of ash hoppers provided with electric heaters. The control of ESP would be

based on microprocessor using semi-pulse device. The design of ESP will be

such that the outlet dust-burden does not exceed 50 mg/Nm3 at BMCR with

worst fuel mix.

j) Soot Blowing System (Optional)

The boiler will have provision for installation of automatic sequential electrically

operated type steam soot blowers with facility of manual retraction in emergency

for on-load cleaning of the heat transfer surfaces.

k) Boiler Structures and Accessories

The complete boiler will be top supported type and would be provided with all

supporting steel structures, platforms, galleries, elevator and stairways for easy

approach and maintenance of the unit. Adequate weather protection would be

provided for instruments and operating personnel. Necessary lining and

insulation along with fixing materials to limit outside surface temperature to a

safe level would be provided. Monorails and hoists required for handling heavy

equipment, motors, fans etc. would be supplied along with the steam-generating

unit for ease of maintenance.

l) Bed Material filling system

Provision shall be kept for separate silo for bed material and bucket system for

filling the silo. Pipe line arrangement from silo to boiler bed with gates,

accessories shall be made.

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4.2 Main Fuel Unloading, Transportation and Feeding System

a Design Criteria and Assumptions

The Fuel Handling Plant for the station is designed to operate with shale, Jhama

with washery rejects available from mine and washery are located within a

kilometer of the project site. While shale and jhama coal will be supplied in

dumper, washery rejects shall be transported in conveyor. For the purpose of

equipment selection, fuel quality mentioned in Exhibit-1 of the report has been

adopted.

Adequate redundancy has been adopted to ensure uninterrupted operation of the

system. The followings are the salient points of design basis of the Fuel Handling

Plant:

b System Description

The scheme of the proposed Fuel Handling System is shown in Drawing No.LII-

KEOE-12022-40121-001, Rev-A. The layout is shown in the Plot Plan (Dwg. No.

LII-KEOE12022-00110-001, Rev-A.

For the proposed station, twelve (12) hours of operation in a day would be

adopted for the fuel handling system. The system design considers new stream

of conveyors for conveying shale and jhama coal from either the primary crusher

outlet or the stockyard and washery rejects directly from stockyard to proposed

Unit #2 (Phase-II), via secondary crusher for Phase-II.

One single stream 300TPH capacity along with primary crusher, screen and

vibrating feeder has been envisaged from reclaim hoppers of Jhama and shale

unloading yard to stock pile for general shift operation only. Two stream of

conveyors 150 TPH capacity along with secondary crusher, screen, vibrating

feeder, fixed tripper conveyors have been considered from reclaim hoppers of

secondary crusher to bunker level feeding for 12 hrs of operation. Two streams

of conveying in Phase-I, shall have a provision for feeding arrangement to

proposed unit –II at the bunker level, in case of exigency. Primary crusher

300TPH has been considered with a view to feed jhama coal to existing Unit-I

also in future for AFBC.

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Shale, Jhama coal and washery reject shall be fed successively and

predetermined ration on weight basis on same belt for preparation of good mix in

the crusher.

Shale/ Jhama coal, on receipt at plant end by dumpers at (-) 300 mm size, would

be fed to the primary crusher house via one new conveyor (300TPH) which will

be installed for proposed unit-II to carry Shale/ Jhama coal from dumping area to

Primary Crusher House, which will also be installed new for the proposed unit-II.

Here, the size would be reduced to (-) 80 mm. The primary crushing unit would

be equipped with one vibrating screens followed by two (1 working + 1 standby)

rotary breakers (one for jhama and one for shale) or single crusher (Jhama &

shale). Crushed coal received from either crusher or single crusher shall be

stacked at stockyard by tripper conveyors in two different locations. Crushed

shale/Jhama coal would thereafter be led either to crushed shale/ Jhama coal

pile by conveyor, which will be installed new for proposed unit-II or to the

secondary crusher house, which will be installed new for proposed unit-II.

Washery rejects, received at the plant by Tripper cum Spreader conveyor, in

sizes (-) 80 mm would contain surface moisture due to the floatation process

adopted in the washery. Washery rejects would be spread in the yard with

bulldozer to permit water evaporation and dried fuel would be directly fed to the

secondary crusher. Shale/ Jhama coal after primary crushing and washery

rejects after adequate drying shall be fed to the surge hopper of the secondary

crusher house to permit mixing. Fuel thus mixed shall be crushed in the

secondary crushers via screens and then conveyed to the powerhouse to feed

fuel-bunkers. Recycling shall be used to ensure the feed size of the fuel as (-) 6

mm. The oversized component of the screens shall be recycled back the

secondary crusher by high lift conveyors.

The secondary crushers, vibrating screen, bunker conveyor and high lift

conveyor shall be provided with standby units.

Transfer points at suitable locations between new reclaim hoppers and

Secondary crusher House (Phase-II) and between secondary crusher House and

boiler bunkers (phase-II) shall be located.

Considering the magnitude of fuel requirement of upto 60 TPH (with worst fuel)

feeding by pay loaders to the ground hoppers is considered adequate for the

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unit. In view of proximity of fuel source, a stock of 7 days’ requirement of shale,

Jhama coal and washery rejects is also considered adequate. The system

design would consider that for either type of fuel, the power generating block

could be operated at MCR. This arrangement would be operational under

exigency conditions.

Crushed fuel from secondary crusher would be transported to the bunkers by the

inclined conveyors which will finally feed the bunker level conveyors via fixed

tripper conveyors.

The conveyor structure from the stackyard through secondary crusher to the

bunker level will be installed. Bunkers will have a storage capacity of about 16

hours’ fuel requirement for the boiler. The bunkers will be provided with rod and

slide gates, arch breakers, etc. to facilitate operation. Necessary belt weighing at

bunker level conveyors, electro-mechanical and capacitance type level

indicators, fuel sampling units, flap gates etc. would be provided in the system as

required.

C Salient Features of the System

The major equipment for the fuel handling plant for the proposed unit-II are listed

below:

1. Belt conveyors : 1) One stream conveyor line of 300 TPH

from the ground hopper of the unloading

stackyard to the stock pile area through

primary crusher. One tripper shall stack

jhama & shale in two different locations.

2) Two stream of conveyor line of 150TPH

from stockyard to bunker level through

secondary crusher and transfer points

and finally fixed tripper belt conveyors to

bunker hoppers.

2. Vibrating feeders : 300 TPH (-300mm) for conveyer upstream

of primary crusher and 150 TPH for

conveyer upstream of secondary crusher

(-80mm) capacity each as required

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3. In-line magnetic separators : Qty as required by the system

4. Vibrating screens : 300 TPH (-80mm) (Primary Crusher House)

and 250 TPH (-6mm) at upstream of

secondary crusher

5. Primary Crusher (Cap. 300TPH)

Rotary breaker type : 2 x 100 % single roll crusher

6. Secondary Crusher (Cap. 150 TPH) : 2 x 100 % Hammer mill

7. High lift crusher : 100 TPH (2 x 100 %)

8. Fixed Tripper Belt Conveyor : As required

(Cap. 150 TPH)

Other Salient Features:

Metering of Coal

Adequate number of electronic belt scales would be provided on conveyors at

appropriate places to monitor the inflow of coal quantity into the plant and the coal

feed to the bunkers.

Coal Sampling System

Coal sampler will be provided in the junction tower to collect the coal samples for

analysis of the raw coal received in the station and feeding to the bunkers.

Tramp Iron Detection and Removal

Tramp iron and other magnetic materials would be removed by means of In-line

magnetic separators provided on the head pulleys of conveyors leading to the

crusher house

Fire Protection

Fire hydrants will be provided at all tunnel entry points, junction towers/crusher

house, bunker gallery and along the overhead conveyors. Fire hydrants would also

be placed along the periphery of the fuel stock pile for fire fighting.

Dust Control

Suitable pollution control measures like dust extraction and dust suppression

systems will be provided at different transfer points and crusher houses and

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ventilation system to supply fresh air in underground tunnels will be provided. In

addition, roof extraction fans will be provided in essential areas like crusher house

and SG bunker floors. Pressurized ventilation with unitary air filter unit will be

provided for control room and MCC buildings of coal handling plant.

Stockpile area will be provided with automatic garden type sprinklers for dust

suppression as well as to reduce spontaneous ignition of the coal stockpiles.

Necessary water distribution network for drinking and service water with pumps,

piping, tanks, valves etc. will be provided for distributing water at all transfer points,

crusher house, control rooms etc.

Controls

A centralized control room with microprocessor based control system (PLC) has

been envisaged for operation of the coal handling plant. Except locally control

equipment like travelling tripper, dust extraction/ dust suppression / ventilation

equipment, sump pumps, water distribution system etc., all other in-line equipment

will have provision for local control as well. All necessary interlocks, control panels,

MCC’s, mimic diagrams etc. will be provided for safe and reliable operation of the

coal handling plant.

4.3 Ash Handling System

To meet the requirement of the prevailing environmental norms of the State

Pollution Control Board (WBPCB) and Central Pollution Control Board (CPCB)

guideline, the system considers extraction and disposal of ash in dry form for the

proposed station.

The quantum of ash generation would depend on the plant load factor and the

quality of fuel. In keeping with the designed system capacity envisaged for fuel

handling plant, worst fuel parameters from the source mentioned earlier is used for

equipment selection of the Ash Handling Plant.

The Ash Handling System control room will be located adjacent to ESP control

room for ease of operation.

For the design of the Ash Handling System, the following data has been

considered.

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Table – 4.2

Design Parameter for Ash Handling Plant

Parameter Value

Hourly Shale, Jhama coal and/or washery rejects firing rate

for 1 no. 189 TPH boiler at BMCR condition

59.1 TPH

Total % ash content in fuel, considered for design of ash

handling system 65.46 %

Ash Generation for boiler 39 TPH

Distribution of total ash produced for design of ash

handling system

a) Bed ash 20%

b) Fly ash 90%

Generation of Ash in both boilers, based on above ratio

a) Bed ash 7.8 TPH

b) Fly ash 34.8 TPH

Design capacity of Ash handling system (considering 50%

margin)

a) Bed ash 12 TPH

b) Fly ash 52 TPH

Capacity & Time Cycle

In case of CFBC boilers, bed ash generation may go up to 20% of total ash

generated, but Fly Ash generation will increase to 90%. Considering the quantum of

ash generated, intermittent ash removal arrangement with necessary storage

hoppers to hold ash for 8 hours is envisaged. Bed ash extraction for 2 hours per

shift and fly ash evacuation in 4-4.5 hours/shift has been considered.

Bed Ash Handling System

In Drawing No.LII-4236-406-W-101 of DPR (2007), the schemes proposed for the

ash handling plant of the station is shown. The scheme proposes, dry extraction

and disposal of bed ash via bed ash cooler, bed ash collection hoppers, ash

transmittal vessels and ash conveying pipe up to the bed ash silo.

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Fly Ash Handling System

Fly ash from ESP, air heater and economizer collection hoppers and stack hoppers

would be conveyed through pressurized conveying system to the F.A. silos. As

shown in the above drawing, conveying air compressors would be used to transfer

both bed ash and fly ash to the respective silos. De-ashing from fly ash hoppers

would operate on an auto sequence mode with total operation time spanning 4 to

4.5 hours in a shift. One stream of pneumatic conveying extraction system have

been considered for the boilers. The ash would be conveyed through pressure

conveying system up to the fly ash silo located near the eastern boundary of the

plant. The design capacity of the pressure conveying system would be optimized to

suit this requirement.

Dry fly ash would thereafter be transported in trucks from the silos to mine for

backfilling. An additional nozzle is provided below the silos for adopting any other

mode of transport in future. Normally, dry disposal mode would be operational.

Provision is kept for selling ash from the dry ash disposal spout of silo to the

possible users. A small quantity of water will be sprinkled to moisten the ash in the

silo unloaders prior to loading in the trucks for disposal.

4.4 Plant Water System

The plant water system will be designed to supply cooling water make-up based on

cycle of concentration 4 and other consumptive water requirement for the proposed

1x20 MW Unit. A closed cooling water system employing Induced draft-cooling tower

has been envisaged for the proposed unit to minimize the plant water intake

requirement.

Scheme for proposed Plant Water system is shown in the DPR-2007 Drawing No.

LII-4236-401-W-101: Water Balance Diagram and Dwg. No. LII-4236-405-W-102:

Flow Diagram for Plant water System. However some change has been made drg no

LII-KEOE12022-40021-001-1(WCC)R-A & LII-KEOE12022-40021-001-2 (ACC), R-

A: Plant water System & LII-KEOE12022-00027-001-1(WCC)R-A & LII-

KEOE12022-00027-001-2 (ACC), R-A: Water Balance Diagram attached with this

report. The total plant water requirement for both the units is indicated in Table-.

Recently CPL is going to install High concentration slurry ash disposal (HCSD)

system in Unit#1 for filling the Ash in open mines. Out of 41 cum/hr required for

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HCSD system, cooling tower blow down gives 20 cum/hr and balance water is being

drawn from existing system. Provision for One more HCSD for Unit #2 has been

envisaged in line with Unit #1. Additional water requirement for this can be supplied

from the existing system.

4.4.1 River Water Intake Water System

Raw water would be drawn from river bed through bore wells. With consumptive

water requirement is represented in table below, it is estimated that either 12nos. (if

WCC) or 4 nos.(if ACC) pumps will be additionally installed in Phase-II, considering

that ten (12) nos. bore well pumps already installed in Phase-I. This will ensure

adequate redundancy. Raw water would then be collected in a semi-underground

reservoir near to river. From this reservoir, raw water is presently being pumped to

plant by four (4) nos. of pumps (2W +2S) to in-plant raw water reservoir. Additional

either 4 nos. (2W+2S) for WCC or 2 (1W+1SB) nos. intake pumps shall be installed

in Phase-II.

Sl. No.

Items Unit Unit#1 Unit#2

Remark WCC With HCSD

WCC with HCSD

ACC with HCSD

1 Plant Water m3/hr 180+41.5

(for HCSD) 181 52

2 Bore wells nos. 10+2 (for HCSD)

12 4

As discussed in meeting on 25.07.12, water received from existing 10 pumps (5W+5SB) is 175m3/hr. Hence capacity of each pump available 17.5m3/hr

3

Second pipe line from Intake reservoir to Plant

NB 250 250 250

As discussed in meeting on 25.07.12 additional 250 NB pipe shall be consider for proposed unit

4 Raw water Reservoir pump (outside plant)

nos. 2+2 2+2 1+1

As discussed in meeting on 25.07.12, water received from existing 4 pumps (2W+2SB) is 173m3/hr

5 Raw water Reservoir pump (outside plant)

nos. 1+1 1+1 1+1 Pump capacity for ACC option shall be less than existing

The cross-country raw water intake pipeline covering a route length of about 5 Km.

is of mild steel construction with wrapping & coating and provided with cathodic

protection.

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One number 250 mm dia. raw water intake pipe line is already installed for supplying

raw water from outside plant reservoir to in-plant raw water reservoir already

existing and common for both Phase-I & II. Another 250 mm dia. raw water intake

pipeline will be installed in Phase-I to augment the flow of raw water to the in-plant

raw water reservoir.

The available data on raw water analysis is given in Exhibit-4 of DPR (2007). It may

be noted that as raw water would be drawn from river bed, total suspended solid

(TSS) is expected to be reasonably low other than in rainy season.

Availability of River bed water for the extension unit needs to be examined and

confirmed by competent authorities. Besides the pumping arrangement including

river bed bore well locations are also required to be finalised in consultation with the

aforesaid authorities.

4.4.2 Raw Water Distribution System

The station is having 7 days raw water storage facility at the plant which can cater

to any exigency condition in water supply system.

The present raw water pump house shall be extended or new pump house is to be

erected to accommodate the new raw water intake pumps required for Phase-II.

At the inlet of in-plant raw water reservoir, a cascade aerator will be provided to

oxidize the iron present in the raw water. Raw water from the in-plant reservoir

would be pumped by raw water supply pumps primarily to supply water to cooling

tower as make-up. Two (2) nos. pumps are presently installed in phase-I. Additional

two (2) nos. pumps ( same capacity of existing phase -1 for WCC option or smaller

capacity for ACC option) will be installed in phase-II. A static mixer would be

provided on the discharge of raw water pumps, where Sodium Hypochlorite would

be dosed to precipitate out Fe as Fe(OH)3. One branch will be taken to Cooling

Tower through ‘Make-up water Filter cum SSF’. Another branch from the in-plant

raw water pump discharge main header will be taken to filtered water storage tank

through a filter. The above filters will remove the solids from the raw water streams.

The requirement of Potable water, Service water and DM water would be catered

from filtered water tank.

The filtered water tank 80 cum is located in the water treatment area and common

for both the units of Phase-I & II. From the discussion, it is observed one more filter

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water tank of capacity 200 cum is required to be installed for Phase-II extension.

4.4.3 Circulating Water (CW) System

From the raw water analysis available, it may be noted that the total dissolved solid

in the raw water is reasonably low and with acidulation/dosing a favourable cycle of

concentration could be attained. For the purpose of estimation of the study a cycle

of concentration of four (4) has been adopted.

On the basis of available parameter of turbine generator set and considering a

differential temperature across the condenser as 9 °C cooling water in circulation is

estimated at 7830 m3/hr for unit -2, which includes the requirement of auxiliary

cooling circuit. But for Air cooled condenser only 460 m3/hr for the auxiliary cooling

circuit. The makeup water requirement for the Induced Draft Cooling Towers at full

load will be around 174 m3/hr (if WCC) or 10 m3/hr (if ACC) for unit-2. The cooling

tower blow down is expected to be about 39.6 m3/hr (if WCC) or 2.3 m3/hr (if ACC)

for unit-2. The raw water would be used as cooling media for condenser cooling (for

water cooled condenser) and auxiliary cooling circuit. For water cooled condenser

cooling water would be pumped from the cooling tower basin by 3x 50% capacity

cooling water pumps to take care of condenser heat load. Through a separate set of

auxiliary cooling water pumps (2 x 100% capacity) the heat load of heat exchangers

of auxiliary equipment of TG and SG auxiliaries would be dissipated and the return

hot water would be fed to the circulating water return header.

For Air cooled condenser only 2x100% capacity auxiliary cooling water pumps to

take care the heat of heat exchangers of auxiliary equipment of TG and SG

auxiliaries.

4.4.4 DM Plant and Heat Cycle Make-Up System

Total power cycle make up requirement including regeneration will be 4.5m³/h for

each unit of power plant. The present DM plant capacity (10 m³/h) is adequate for

requirement of both phase-I and phase-II units. However, another chain for identical

DM plant of 10 m3 capacity will be installed as common standby. One (1) no. DM

tank is already installed in Phase-I. One (1) no. additional DM tank shall be installed

in Phase-II.

4.4.5 Service Water & Potable Water System

Various consumption points like air washer unit make-up, various pump gland seals,

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ventilation system, etc. to be suitably integrated and interfaced with the unit of

phase-I facility.

For potable water supply to the station, to be suitably integrated and interfaced with

the unit of Phase–I facility of filtered water with necessary chlorine dozing is

envisaged. On apportioned basis, about 1 m3/hr of potable water may need to be

supplied for proposed plant of phase-II potable use. Filtered water from the filter

water storage tank would be supplied for air-conditioning system make up and DG

set cooling, pump capacity of existing system of phase-I unit would be augmented

to cater the requirement of phase-II unit for use as common system.

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SECTION – 5

ELECTRICAL SYSTEM AND EQUIPMENT

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5. ELECTRICAL SYSTEM AND EQUIPMENT

5.1 ELECTRICAL SYSTEM ARRANGEMENT:

The scheme for the proposed 20 MW Unit is envisaged as similar to that of the

existing 40 MW Unit considering the requirements of efficient and reliable operation

of the plant in start-up, normal as well as adverse system condition.

The generation voltage is envisaged at 11 kV, similar to the existing one and the

generator will be directly connected to existing 132 kV outdoor switchyard through

11/138 kV generator transformer for evacuation of power. To evacuate power to

Ganrui Substation of WBSETCL and to receive start up power for power plant

auxiliaries the existing 132 kV outdoor switchyard will be augmented to

accommodate two (2) nos. bays. The additional 20 MW from proposed Unit will be

evacuated to Ganrui Substation of WBSETCL through existing double circuit 132

kV overhead line.

In order to accommodate extra 20 MW power, the adequacy of the existing double

circuit line as mentioned above and the present capacity of Ganrui Substation of

WBSETCL shall be checked by necessary electrical system studies. Moreover

necessary coordination may be done by CPL with WBSETCL in this regard.

Start-up power requirement for the proposed 20 MW Unit will be made available in

the following two ways:

a. Through 132kV System via 132/6.9kV Station Transformer.

b. From 6.6 kV switchgear of existing 40 MW Unit, for initial start up only.

The house load power will also be available directly from generator terminal

through one (1) no. 11/6.9 kV Unit Auxiliary Transformer (UAT).

Capacity of the Station Transformer for the proposed unit shall be such that it can

take the entire start up load of the existing as well as proposed unit during the

absence of the existing Station Transformer.

Unit Auxiliary Transformer for proposed unit shall also be sized to take care of the

unit load of both the unit during absence of the existing Unit Auxiliary Transformer.

Necessary fast bus change over facility shall need to be provided between the

existing 6.6kV Switch Gear as well as proposed 6.6kV Switch Gear.

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In the existing intake water system, there are 10 nos. 13kW bore well pumps and 4

nos., 55kW raw water pumps. For the proposed 20MW, 10 nos., 13kW bore well

pumps and 2 nos., 55kW raw water pumps are also envisaged. The existing

system is being fed by 1 no. 11/0.415kV, 315kVA & 1 no. 11/0.415kV, 100kVA

Transformer. Another 1 no. 11/0.415kV, 315kVA transformer is in stand-by mode.

To take care of new loads, separate 1 no. 11/0.415kV, 315 kVA & 1 no.

11/0.415kV, 100kVA Transformer are envisaged. A new 415V MCC is also

envisaged within the intake pump house adjacent to the existing 415V MCC.

Manual / Auto change over facility is also envisaged between the above three nos.

(2 nos. existing & 1 no. new) 315 kVA transformer feeders. Between the present

running 315kVA transformer and the new 315kVA transformer, if any one will be

out of service, then the present stand-by transformer will automatically come into

service. In the existing system, maximum 6 nos., 13kW bore well pumps and 2

nos., 55kW raw water pumps are running. After considering 2 nos.100kVA and

three nos. 315kVA transformer, it has been observed that the overall running load

is well under the incoming fuse rating of 200A (As per the existing intake fault

calculation report). Therefore, no modification is required for the existing 11kV O/H

line. However, further verification can be done during detail engineering.

The auxiliary power supply system will consist of one (1) no. 6.6 kV station

switchgear, 2x100%, adequately rated, 6.6/0.433 kV Station auxiliary transformer,

2x100%, adequately rated, and associated 415 V PCC & MCC. Provision for

auto/manual changeover from one supply to another will be kept. Downstream LT

distribution to various load centres will be done from 415 V PCC. 2 nos. 6.6/0.433

kV Transformers for CHP PCC are envisaged.

A separate emergency 415 V, 3-ph, 50 Hz Diesel Generator (DG) Set is envisaged

for emergency power supply during shut down of the proposed 20 MW Unit. One no.

emergency MCC will be provided to cater all emergency loads. In case of total AC

power failure, the Diesel generator will start automatically and supply power to 415V

Unit Emergency Switchgear where all essential loads are connected. Provision will

be made for synchronizing 415V Unit Emergency Switchgear with the respective 415

V Unit auxiliary Switchgear for testing and taking in/out of the DG, as required.

For supply of unit and station auxiliary loads of the proposed 20 MW Unit, the

following voltage levels have been envisaged:

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� 6.6 kV level through 11/6.9 kV unit auxiliary transformer and 132/6.9kV Station

Transformer

� 415V level through 6.6/0.433 kV station auxiliary transformers.

� 415V emergency power through Emergency DG set of proposed 20 MW Unit.

� 240V, single phase, 50Hz , AC UPS system for Control and instrumentation.

� 110V DC for emergency drives, lighting, control and protection systems.

6.6/0.433kV auxiliary transformers of suitable ratings will be provided to meet 415 V

Unit / station load requirements of the proposed 20 MW Unit. All 415 V switchgears

will have 2 x 100% incoming feeders, to be supplied by 2 x 100% 6.6/0.433kV

auxiliary transformers, and bus section aliser to achieve maximum redundancy and

reliability during operation.

The design concept of the electrical auxiliary system as a whole is based on the

requirements for the safe and reliable operation of the Plant with provision for easy

maintenance. The design and performance requirements of equipment will be

generally as per latest Indian Standards and the Codes of Practice, IEC

Recommendation. Indian Electricity Rules, wherever applicable will also apply.

5.2 CONSTRUCTION POWER:

For construction activities, power supply from 6.6 kV switchgear of existing 40 MW

Unit has been envisaged.

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SECTION – 6

CONTROL AND INSTRUMENTATION SYSTEMS

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6.0 CONTROL AND INSTRUMENTATION SYSTEM

6.1 Design Philosophy

The control and instrumentation system for the proposed 20 MW Unit with CFBC

technology has been envisaged to be similar to that of existing 40 MW Unit and will be

designed to ensure safe, efficient and reliable operation of the plant under all regimes

of operation, namely start up, shutdown, normal operation, part load operation and

under emergency conditions resulting in cost effective power generation with optimum

fuel consumption and reduced emission levels.

The operation, control and monitoring system envisaged for the plant would be based

on a state of the art microprocessor based Distributed Control System (DCS).

All BOP off-site systems will be controlled and monitored through the DCS.

Monitoring and operation of Plant Electrical Systems will be carried out from the DCS

Operator Stations in the Central Control Room.

Plant abnormal conditions will be alarmed through the Operator Interface Units and

window annunciator. Alarm printer will be provided to print out all alarms with time

tagging and in the chronological order.

Sequence of Event Recording function will be provided for recording and printing

occurrence of events in a chronological order for quick diagnostic of fault and remedial

action.

DCS will perform online performance calculations to determine plant/equipment

efficiency and to detect and alarm unit / equipment malfunctions.

Redundant soft link interfacing provision and seamless integration with Phase-I DCS

has been envisaged for the new DCS of Phase-II.

6.2 Major Control and Instrumentation Systems

The major components of Control and Instrumentation system of the unit will comprise

of the following:

• Distributed Control System (DCS)

• DCS based Steam Generator Control and Protection System or as per

manufacturer’s standard design interfacing with the Plant DCS.

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• DCS based Steam Turbine Generator Control and Protection System or as per

STG manufacturer’s standard design interfacing with the Plant DCS.

• DCS based control system for specified plant BOP off-site packages

• Turbine Supervisory Instrumentation system for STG

• Central Control Room, Control Desk and Electrical Control panel

• Measuring Instruments & flow elements

• Steam and Water Analysis System (SWAS)

• Stack Emissions Monitoring System

• Stand alone BOP off site Package control system

• Uninterruptible Power Supply and Distribution

• Final Control Elements

• Instrumentation & special cables

• Maintenance and Calibration Instruments

• Erection Hardware

6.3 Distributed Control System (DCS)

An integrated functionally Distributed Control System (DCS), synthesized from one

general family of interchangeable multifunction hardware has been envisaged for the

proposed 20 MW Unit.

Distributed Control System (DCS) for the plant will consists of following basic

functions / Subsystems:

• Close Loop and Open Loop Control Systems, which include Interlock and

Protection systems, Sequential Controls, Plant Automation features and

Measurement Systems

• SG & TG control configured in separate and individual Functional Groups in the

Plant DCS.

• CHP, AHP and DM Plant controls through Remote DCS I/O Systems.

• Operator Interface Units (OIU) in Central and local Control Rooms

• Plant Data Communication System including Fiber Optic Communication

between the Central Control Room and the Local Control rooms.

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• Historical Storage and Retrieval

• Plant Performance Calculations

• Sequence of Events Recording System.

• Alarm Annunciation System

DCS shall be provided as a minimum with dual redundant processor subsystem

including CPU, memory and power supply. Redundancy shall be provided such that,

in case of failure of the main processor, the standby processor shall take over

automatically and vice-versa. The changeover shall be bump less and shall not

result any process or system upset.

In case of failure of complete processor system i.e., both processors outputs shall take

fail safe state automatically.

DCS will be of Open Architecture type having high system availability and reliability.

The DCS will provide a comprehensive integrated control and monitoring system to

operate, control and monitor the Circulating Fluidized Bed Steam Generator &

auxiliaries, Steam Turbine-Generator & auxiliaries and power cycle equipment and

auxiliaries including operation and monitoring of Coal Handling, Ash Handling, DM

Water Plants and monitoring of other Balance Of Plant (BOP) off-site systems with a

hierarchically and functionally distributed structure.

All open loop and close loop modulating control functions for the main plant including

Steam Generator and the Steam Turbine Generator and their auxiliaries along with

power cycle equipment and systems will be implemented into the DCS so that

centralized operation of the main plant and associated auxiliaries is possible. DCS will

also include sequential start up, shutdown of the major auxiliaries of Steam Generator,

Steam Turbine and power cycle Equipment and Systems.

The control functions will be backed up by protection, interlocks and safety functions.

This would cause pre-planned actions in cases where unsafe conditions develop faster

than the control capability of modulating controls or before the operator can be

expected to respond to the plant upset conditions in any regime of plant operation.

6.3.1 Close Loop and Open Loop Control System

The control system along with its measurement system will perform functions of Closed

Loop Control System (CLCS), Open Loop Control System (OLCS) including protection

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functions, measurement and monitoring of signals and alarm function.

Close loop controls such as Fuel flow control, Furnace pressure & air flow control,

Drum level control, Hot well level control, Heater level control, Deaerator Level Control,

Make-up water Control, recirculation control etc will be configured in the DCS.

Start / stop sequence control and protections of ID & FD Fans, Boiler feed pump,

Condensate extraction pump, HP/LP heaters, Make-up water pumps, equipment

cooling water pumps and all motorized drives will be configured in the DCS.

6.3.2 Operator Interface Units (OIU)

Operator Interface Unit will consist of Operator Terminals (OT) based on latest PC or

Work Station with redundant communication link, 21” Colour Graphic LCD (TFT)

Monitor, Keyboard and mouse, printers.

Dot Matrix, Colour Printers etc. will be provided for generation of logs, reports,

Graphics pages and miscellaneous printouts.

6.3.3 Data Communication

Different subsystems of the DCS are interconnected through redundant bus

communication system. This includes redundant data Bus, redundant Plant Data

Highway and other applicable bus subsystems. The communication bus system will

be in hot redundant configuration with no loss of data or loss of communication in

case of failure of one bus.

6.3.4 Historical Storage and Retrieval (HSR) System

Historical Storage and Retrieval system (HSR) will collect and store data and

parameters including trends, alarms and events from DCS database periodically and

automatically to removable DVD / optical disk data storage devices, once every 24

hours for long term storage and retrieval.

6.3.5 Performance Calculation

Plant Performance Calculations will be done by automatically retrieving data from

plant data highways. Facility to display all data related to Performance Calculations

will be provided on Operator Interface Units (OIU)

6.3.6 Sequence of Event Recorder (SER)

Sequence of events recording system (SER) of 1 milli sec resolution with adequate

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redundancy features will be provided as an integral part of DCS to log trips, cause of

trips and other important faults to diagnose the cause of plant trip.

6.3.7 Alarm Annunciation System

The alarm systems will contain all alarms for a safe and reliable operation of the

plant. The alarm system will cover all pre trip and trip alarms related to unit and to

auxiliaries. The alarms will be displayed on DCS Operator Interface Unit and will be

printed on alarm printer chronologically.

6.3.8 Electrical Systems Operation and Monitoring:

Suitable hardwired / software communication interface will be provided between

Plant electrical control, protection and synchronizing systems and DCS.

Monitoring, Operation and Control of new 132 kV bays of the proposed 20MW unit

will be carried out by the new 132 kV bay control units as well as by the existing

DCS. For that, required modification shall need to be done in the new Control Room.

6.3.9 System Programming and Documentation

The engineering workstation will be an integrated system providing facilities for the full

application engineering of the control and automation system including the operator

interface. This includes all the functional software and hardware engineering, as well as

all field component configuration and connection, cabling and termination engineering,

and VDU display and report configuration.

6.4.1 Steam Generator (SG) Control System:

The Steam Generator control system will include the following major functional blocks:

• Burner Management System with Flame Scanning System.

• Furnace Bed Temperature Control

• Furnace Bed Level Control

• Steam Temperature Control

• Drum Level Control

• Auxiliary pressure reducing and desuperheating station (APRDS) Control

System.

• Coal Feeder Control System

• Steam Generator Auxiliaries Controls

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• Soot blower Control System (if envisaged)

The Steam Generator control and protection system is configured in the Plant DCS.

6.4.2 Steam Turbine Generator (STG) Control System

The STG control system will typically include the following functional groups:

• Electro hydraulic Governing Control System (EHGC)

• Turbine Protection System (TPS)

• Turbo-supervisory Instrumentation (TSI)

• Turbine Bypass Control System

• STG Auxiliaries Control System

The Steam Turbine Generator control & protection system is configured in the Plant

DCS.

6.5 Alternative Philosophy

Alternatively, if proprietary SG & STG control system by manufacturer is provided, it will

be complete with all the functional blocks described above with operating interface

arrangement. The control system will have redundant software link with the Plant DCS

and some of the critical signals for protection of the SG and STG will be hardwired to

the plant DCS.

6.6 DCS based Balance of Plant off site control system:

The control, interlock, protection and start / stop operation for all the BOP packages

will be realized in the Plant DCS. Local and Remote DCS Operator Work Stations

will be provided for both local and remote monitoring and operation.

6.7 Stand Alone Balance of Plant off site control systems

Compressed Air System, Air conditioning and Ventilation System, Fire Detection

System, Chemical Dosing System etc. will be carried out from their stand alone

control system like PLC / Relay based Local Control Systems.

6.8 Turbine Supervisory Instrumentation system

Turbine Supervisory Instrumentation (TSI) will be complete with all Vibration

Sensors, Amplifiers, Special Cables and monitors with all necessary equipment and

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accessories.

TSI parameters will be connected by hardwired link to DCS for centralized

monitoring.

6.9 Vibration Monitoring Systems for HT Drives

Vibration Monitoring Systems complete with Sensors, Amplifiers, Special Cables and

monitors with all necessary equipment and accessories will be provide for the HT

Drive equipment like CW Pumps etc. The Vibration Monitoring parameters will be

hardwired to Plant DCS for centralized monitoring.

6.10 SCADA

A separate SCADA shall be envisaged for control & monitoring of intake submersible

pumps. Soft-link shall be provided between Plant DCS & SCADA for monitoring the

same from Plant DCS.

6.11 Control Panel / Control Desk

Control Panel

A freestanding unit control panel will include Measuring Instruments, Annunciation

windows, Recorders, Push Button stations, Emergency consoles for Boiler and STG

etc.

Power house building shall be extended and new Central Equipment Room (CER)

shall be created in the extended power house building. All required I&C and

electrical panels shall be placed in the new Central Equipment Room

Control Desk

The Control Desk will house Operator Interface Units (OIUs), including Monitor,

Keyboard, Mouse and the Emergency pushbuttons for Tripping of Boiler, Steam

Turbine. The Control Desk will also house Telephone Hand set for communications.

Power house building shall be extended and new Central Control Room (CCR) shall

be created in the extended power house building and all required Control Desks &

HMI’s shall be placed in the new Central Control Room. Fire alarm panel and panel

for public address system shall also be located in the new Central Control Room.

The existing public address system and EPABX system can be upgraded and

extended up-to unit-2. However being an old system availability of spares in future

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may be an issue and to be addressed by the supplier. Or a new public address

system and EPABX system shall be installed for the new unit and same can be

extended to unit-1 for exchange of information avoiding physical interaction between

two systems.

6.12 Control Room Equipments

The new central control room will be sized to accommodate additional staff and

observers for commissioning, testing, start-up and emergency situations.

The new control room will house the following various equipments as a minimum:

• Control Panels, Control Desk (UCD), Work-station with all required accessories

and printers in the new Central Control room.

• DCS system cabinets and electrical relay cabinets and other systems panels (as

required) in the new Control Equipment room

• Shift charge Engineer’s monitor with keyboard/ mouse and printer in new Shift

Charge Engineer’s room.

• Engineering Work Station with keyboard / mouse along with the Color Graphic

printer in new System Maintenance Engineer room.

Public Address System panels, Fire alarm system panels etc will be suitably housed

in new Central Control room.

6.13 Measuring Instruments

Microprocessor based reliable HART compatible Smart Transmitters with adequate

redundancy, the Pressure/ Differential pressure/ Temperature/ Flow switches,

Thermocouples and RTDs will be used as primary Instruments for measurement of

various process parameters.

Local Gauges like Pressure, Temperature and Level Gauges will be provided for

local indication of the process. Process Switches will be provided for alarm

monitoring and protection and interlock purposes. Various flow sensors like Orifice

plates, flow nozzles, etc. will be used for measurement of flow.

Flue Gas oxygen measurement will be carried out by in-situ Zirconium Oxide Type

Sensor.

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6.14 Steam and Water Analysis System (SWAS)

A centralized comprehensive Steam and Water Analysis System (SWAS) for each

unit will be provided for continuous on line monitoring of water and steam purity in

the plant cycle. Measurements of Conductivity, pH, Hydrazine, Dissolved Oxygen

and Silica will be provided.

The SWAS room will be suitably located in the Main Plant Building.

Analyzer output signals from the SWAS Panel will be hardwired to the Plant DCS for

centralized monitoring.

6.15 Stack Emission Monitoring System

Continuous Emissions Monitoring System (CEMS) for monitoring of Flue gas

Emissions from the Stacks of the Plant will be provided, which will consist of the

following analyser Instruments:

• Oxides of Nitrogen NOx

• Sulphur Dioxide SO2,

• Carbon Monoxide CO

• Stack Opacity Monitor.

The emission parameters will be hardwired to Plant DCS for centralized monitoring.

6.16 Ambient Air Quality Monitoring System

Analytical Instruments for Ambient Air Quality Monitoring will also be provided to

check upon the ambient air quality around the Power Plant as per MOEF / Pollution

Control Board guide lines.

6.17 Uninterruptible Power Supply (UPS) and Distribution

Uninterrupted power supply (UPS) system in which 2 UPS operate in sharing mode

will be provided to cater to single phase, 230 / 120 V AC 50 Hz, 2 wire power supply

requirements of instrumentation and control systems viz. DCS Cabinets, man-

machine interface equipment, analysers, instruments mounted on the unit control

panel and other independent systems. Other voltages required will be derived from

the UPS source. The UPS system will be housed in a separate room suitably located

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in the Main Plant Building.

6.18 Final Control Elements

Final control elements will be provided with electro - pneumatic positioners,

electronic position transmitter of 4-20 mA output, air lock relay, air filter regulator,

hand wheel, limit switches, solenoid valves and other accessories in accordance

with the system requirements.

All IGV shall have operating wheel for local operation and locking arrangements for

online maintenance.

6.19 Instrumentation & Special cables

Individual pair shielded and overall shielded twisted pair colour coded copper cables

will be used for analog signals and overall shielded cables would be used for digital

signals. All these cables will be FRLS and unarmoured. The conductor size of the

field cables from field instrument to Junction Box will be of 1.5 mm2 and that for

Multipair / Multicore cables from Junction Box to the Control Room will be of 0.5

mm2.

6.20 Maintenance and Calibration Instruments

One set of Maintenance and Calibration Equipment for instrumentation and control

system will be provided. This would consist of calibration equipment such as hand-

held calibrator for smart transmitters, electronic test bench, pneumatic test benches,

dead weight tester, manometers, air sets, RCL Bridge, digital channel simulator,

logic probe, testing meters / devices / calibrators for at site testing and calibration,

etc.

6.21 Erection Hardware

All required installation hardware including impulse pipes, tubes, valves, manifolds,

fittings, cable trays, holders, angles and conduits etc. required for proper installation

and interconnection of instrumentation and control system will be provided.

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SECTION – 7

CIVIL WORKS

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7. CIVIL WORKS

This Civil work for plant will cover design and construction of all civil, structural and

architectural works including site development/formation, foundation & super-

structure required for all equipments, buildings & structures, all necessary

infrastructural works required and associated works that are necessary for the

construction, operation and maintenance of the Power Plant.

The civil work broadly includes site grading , all excavation, back filling, piling work,

concrete work (plain and reinforced), structural steel work, water proofing, roads,

drainage, paving, sanitary, plumbing, all architectural and finishing work as required

for the Project.

7.1 Land Development

The land is fairly flat, sparsely vegetated with trees / small shrubs. However,

depending upon the topographical survey, the reduced levels / elevation of various

finished ground level, finished floor levels, will be finalized. A thorough study of

terrain elevation will be made. The roads / storm water / sewage system will be

planned by taking care of all relevant data. The systems thus planned will not be

having any maintenance problems later. In case of minor cutting / excavations /

filling is required, the same would be carried out to arrive a levelled surface. The

major cutting and filling shall be carried out in the extended portion of coal stock pile

area, cooling tower area. Rest of the proposed area shall also be cut and filled as

required to maintain the desired finished grade level.

7.2 Geo-technical Investigations

The power plant area is basically an agricultural land, nearby to open cast coal mine.

The sub-soil at site is basically a residual soil formed due to physical and chemical

disintegration of parent rock ie., argillaceous and carbonaceous shale. The average

depth of residual soil including the top graded soil is about 3.23m. The soil cover is

underlain by completely weathered and highly weathered rock formation for a total

thickness of about 3.0 m. Detailed Soil Investigation will be carried out before

commencement of engineering design. Adequate numbers of borehole test shall be

carried out at every individual location for heavy static equipment foundation (e.g.-

ESP, Boiler foundation etc), vibrating equipment (e.g.-TG foundation, crusher

foundation etc) and major structures & buildings such as chimney, ash silos, cooling

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structures, TG building, Crusher house etc. As the proposed site was initially

undulated with numbers of major ups and downs and it is subsequently filled up with

soil, special care shall be taken in design of foundation for heavy equipment and

major structures, specially located in filled up soil to maintain the serviceability as

well as safety of foundations & structures.

As the adjoining area being surrounded by open cast coal mines, the aspect of

vibration arising from blasting disturbance from mines is to be considered.

7.3 Topographical Survey

The topographical survey will be conducted and the general information on land

terrain will be ascertained to plan necessary infrastructure facilities.

7.4 Plant Layout

The plot plan obtained from DPR (LII-4236-000-T-001, R0) dated August 2007 has

been modified and necessary changes have been incorporated in the revised one

(DRG NO:- LII-KEOE-12022-00110-001-WCC & LII-KEOE-12022-00110-001-ACC,

Rev-A). Necessary modifications have been made in coal stock pile area, ash

storage area, raw water reservoir area & BTG area. A pump house for unit-II is also

added in raw water reservoir.

The land for the plant is already acquired.

The layout indicates the area for proposed unit and other additional facilities.

All plant roads, culverts and rain water drainage shall be provided as depicted in

DPR. In addition to the above, an approach road to coal yard needs to be provided.

7.5 Water Intake

The raw water intake facility by providing bore holes in the river bank has been

already located. The same facility shall be augmented for phase-II. The water pipe

lines will be suitably supported on concrete / steel supports on its route to the plant.

Wherever cross over bridges are required, the same will be planned by meeting

statutory requirements.

Flow diagram (dwg. no. LII-KEOE12022-40121-001, Rev-A) has been modified

showing the necessary augmentation required for phase-II.

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7.6 Plant Buildings

a) Main Plant Building

Main Plant Building in the Power Block area is proposed to be a continuation of

the present building. This proposed building will comprise of Main Power House

Building (turbo-generator bay, and Electrical bay / SG Feed Pump, Heater and

Deaerator bay, Central control room, Control equipment room etc.). The building

would be a non-basement structure. The Steam Turbine Generator and auxiliary

equipment will be located in the A-B bay of the building having 17 metres span

and is accommodated in a length of 45 metres, which includes one unloading /

maintenance bay. The heaters are accommodated in the B-C bay (heater bay)

having a span of 10.5 metres.

The turbine - generator bay would have three floors - ground floor at 0.00 M

level, mezzanine floor and operating floor. Localised O & M platforms at required

levels would be provided. The desecrator would be located at roof level in the B-

C bay (heater bay). Road and rail access will be provided to the unloading and

maintenance bays for unloading TG components and auxiliary equipment.

The General Arrangement of the Main Plant Building and the sectional view is

indicated in Drawing No. LII-4236-203-W-102 RA and LII-4236-203-W-101 R-A in

DPR (2007).

The building will be of RCC column-framed structures with steel roof beam but

with RCC roof slabs. Brick wall up to 3.0 metres above operating floor level and

side cladding with insulated metal sheet above this level has been considered.

Intermediate steel columns and brick wall at gable end of existing power house

will be removed. Existing EOT cranes (40T/5T) with main and auxiliary hooks of

specified capacity will be used in the new TG bay for erection and maintenance

work of the equipment. The roof of TG bay will be provided with permanent metal

decking sheet of minimum 0.8 mm thickness with zinc phosphate coating and

primer on both sides to act as a permanent shuttering for cast-in-situ RCC slab.

In all other areas roof and floor will be provided with cast-in-situ RCC slab. All

floors of turbine hall (except operating floor and control rooms) will be provided

with non-metallic hardener topping. Operating floor will be provided with IPS floor

finish with floor hardener.

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b) SG Foundations / ESP Foundations

One no. SG and one no.. ESP’s and one no. boiler will be located on the back

side of electrical building. The boilers will have intermediate connecting corridors

between the boilers and control / Electrical building.

c) Auxiliary Buildings

Auxiliary buildings include compressor house, ESP Control room building, Air

washer room, AHP Compressor building, Fuel Oil Pump House, Switchgear &

Control building etc. which will be constructed as specified. Any other building

not mentioned above but required as per system will be provided.

7.7 Paving and Plinth Protection

Paving/plinth protection works around building and in main plat area will be

considered as delineated in DPR.

7.8 Foundations

Foundation for all equipments, tanks, structures and buildings will be considered as

depicted in DPR.

7.9 Transformer area

Civil works in transformer area will be carried out as mentioned in the DPR.

7.10 Switchyard area

Civil works in switchyard area will be done as described in the DPR.

7.11 Chimney

Civil works for RCC chimney will be carried out as mentioned in the DPR.

7.12 Raw Water Reservoir

The existing raw water reservoir will be common for both the units. A partition dam is

being constructed in the middle of this reservoir to make two separate chambers. A

common chamber with RCC wall is being constructed surrounding the existing pump

house. This common chamber will be connected to both the reservoirs by means of

sluice gates. A new pump house for phase-II can be constructed beside the existing

one within the common chamber.

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7.13 Miscellaneous Buildings

Table below indicates list of major buildings / structures planned in the power plant

and type construction:

Table

Misc. Plant Buildings / Structures

SL No Building /Structure Remarks/Type of

Construction

1 ESP Control Room Ground plus one floor; RCC

construction with brick wall.

Roof will be of RCC slab.

2 Air washer room Structural steel column

construction with brick wall.

Roof will be of RCC slab.

3 Ash water and ash slurry pump

house

Structural steel construction

with RCC roof and brick wall

4 CW pump house RCC construction with brick

wall and precoated galvalume

sheet for roof

7.14 Shale, Devolatised Coal (Jhama) & Washery Reject Handling System

The shale, devolatised coal (Jhama) & washery reject handling plant will have the

following structures:

a. Conveyor tunnel and grizzly hopper.

b. Transfer tower foundations.

c. Conveyor trestle foundations.

d. Primary crusher with screen is proposed in RCC structure.

e. Secondary crusher with screen is proposed in RCC structure.

f. Open shale, Devolatised coal (Jhama) & washery reject storage yard and one

separate coal shed for shale

g. Dust extraction system foundation.

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h. Approach road to coal yard

• Transfer Points

Transfer points will be provided at every change of direction of the conveyors.

Approx. four nos. transfer points are required as per present plant lay-out.

Transfer points will have structural steel frameworks with RCC roof and floors.

Cladding will be of sheet metal.

• Conveyor Galleries

Overhead conveyor galleries will be of structural steel frame with metal sheet

roofing and cladding. Walkways are to be provided at the sides of and between

conveyors. The galleries will be supported on steel trestles which will have RCC

foundations.

• Primary Crusher House

Separate buildings will be provided for housing the primary crushers. This

building will be of structural steel framework with RCC flooring and metal

cladding. The crushers will utilize a vibration isolation system with spring

assembly and visco dampers.

• Secondary Crusher House

Separate buildings will be provided for housing the Secondary crushers. This

building will be of structural steel framework with RCC flooring and metal

cladding. The crushers will utilize a vibration isolation system with spring

assembly and visco dampers.

• Fuel Storage Area

The existing fuel storage area is common for both units.

Crusher structure will be RCC framed structure. Its geometry will be decided to suit

vendor’s GA drawings. The crusher house will be provided with 1.2 m high brick

masonry parapet wall at all floors and above it 1 m portion will be open. The

remaining portion below the upper floor and opening will be provided with louvered

type GI sheeting.

The size of covered shed for shale will be provided as per design requirement.

Covered shed for such coal storage will have roof trusses supported on RCC

columns. Top sheeting will be of GI sheet. Side sheeting of 1.0 m height from eaves

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level shall be provided if necessary. The ground floor will be provided with

compacted soil and interlocking bricks / concrete blocks as flooring.

7.15 Ash Handling System

Two RCC ash silos (one for bed ash and one for fly ash) required for ash handling

system. RCC Ash silos and pipe racks will be provided for fly ash handling system.

Pipe trenches as required will be provided in compressor house.

Ash conveying pipe and a RCC silo will be provided for bed ash and Fly ash

handling system. Both fly ash and bed ash from silos will be unloaded in trucks and

with soil cover and sprinkler system.

7.16 Pipe & Cable rack & trenches

Civil & structural works for all pipe and cable racks & trenches in plant area will be

carried out as mentioned in the DPR.

7.17 Sewerage system

Civil works for sewerage system in all over plant will be carried out as delineated in

the DPR.

7.18 Cooling Tower

Civil works for cooling tower will be carried out as mentioned in the DPR.

Alternately, Air Cooled Condenser foundation and auxiliary cooling tower 1x20 MW

structure will be provided in case Air Cooled Condensing system is used.

7.19 Landscaping

Landscaping works in all over plant area will be carried out as described in the

DPR.

7.20 Ash Utilization

The ash generated in the station will be primarily used for sale in cement plants and

brickfields in the locality. Provision will be kept for balance, if any for mine filling (at

Sarishatali) through HCSD system. Complete utilization of ash may thus be

assured. No storage area of ash is therefore envisaged inside the plant.

crescent power limited - environmentclearance.nic.in · pulverized fuel - fired boiler, but can be...

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