CATEGORY PROJECTS (I) Basic Information S.No Item Details

FORM - 1 APPLICATION FOR PRIOR ENVIRONMENTAL CLEARANCE “A” CATEGORY PROJECTS (I) Basic Information S.No Item Details 1 Name of the Project /sites 1X660 MW Super Critical Margherita Coal based Thermal Power Project of Assam Power Generation Corporation Limited (APGCL) 2 S.No. in the Schedule 1(d ) Thermal Power Plants 3 Proposed capacity / area / length / tonnage 1X660 MW Coal based thermal Power Plant. to be handled /command area / lease area Total Project area: 661 acres / number of wells to be drilled Annexure-1: Plant Layout 4 New / Expansion / Modernization New Project issued TOR for 2x250 MW by MOEF, New Delhi vide File No. J-13012/1/2013 - IA. II (T) dated 15 th March 2013. Applied for revised plant capacity of 1x660 MW. 5 Existing Capacity / Area etc. Green Field Project 6 Category of Project i.e. ‘A’ or ‘B’ “A” 7 Does it attract the general conditions? If “Yes” yes, please specify The project site is ~2.5 km away from Assam – Arunachal Pradesh State boundary in South direction Annexure 2: Topographical Map – 10 km radius Annexure 3: Google Earth Image – 10 km radius . 8 Does it attract the Specific conditions? If “No” yes, please specify 9 Location Point Latitude Longitude A 27°18'25.29"N 95°48'3.31"E B 27°18'43.39"N 95°48'43.52"E C 27°18' 11.14"N 95°48'59.52"E D 27°18'15.77"N 95°49'10.94"E E 27°17'55.79"N 95°49'17.07"E F 27°17'34.92"N 95°48'53.88"E G 27°17'26.91"N 95°48'29.13"E Annexure-4: Contour Map referring points A - G Plot / Survey / Khasra No Dag No. 1 Village Sal iki NC , Lek hapani Tehsil Makum mouza, Margherita Revenue Circle. District Tinsuki a State Assam 10 Nearest railway station / airport along with Lekhapani Railway Station ~4 Km, North East distance in kms Ledo Railway Station ~8 Km, North Dibrugargh Airport ~100Km, North West 11 Nearest town, city, district headquarters Nearest Town is Margherita located at ~16km in West along with distance in kms direction and district headquarters is Tinsukia located

1 S.No Item Details at ~55 Km in North West direction from proposed site. 12 Vi llage Panchayats, Zilla Parishad, Sal iki NC, Makum Mouza, Margherita Sub - division, Municipal Corporation, Local body District Tinsukia. (complete postal addresses with telephone Postal Address: SDO, Margherita Sub Division, no.s, to be given) Margherita -786181, Phone No:03751-220207 13 Name of the applicant Assam Power Generation Corporation Limited (APGCL) 14 Registered Address Assam P ower Generation Corporation Ltd. (APGCL), Bijulee Bhavan, 3 rd Floor, Paltan Bazar, Guwahati-781001 15 Address for Co rrespondence Name Mr. Mukut Das Designation (Owner/Partner/CEO) Deputy General Manager Address Assam Power Generation Corporation Ltd. (APGCL), Bijulee Bhavan, 3 rd Floor, Paltan Bazar, Guwahati-781001 Pin Code Guwahati -781001 E-mail cgm [email protected] Telephone no 0361 -2739546 Fax no 0361 -2739546 16 Details of Alternate Sites examined, if any. No alternative sites were examined as the proposed Location of these sites should be shown on project will be commissioned at the proposed site a topo sheet. only. 17 Interlinked Projects None 18 Whether separate application of interlinked Not Applicable project has been submitted 19 If yes, date of submission Not Applicable 20 If no, reason Not Applicable 21 Whether the propos al involves approval / Nil clearance under: if yes, details of the same and their status to be given (a) The Forest (Conservation) Act, 1980? (b) The Wildlife (Protection) Act, 1972? (c) The C.R.Z. Notification, 1991? 22 Whether there is any Government Order/ No Policy relevant / relating to the site 23 Forest Land involved (hectares) Nil 24 Whether there is any litigation pending No Litigation s. against the project and / or land in which the project is proposed to set up? (a) Name of the Court (b) Case No (c) Orders / directions of the court, if any and its relevance with the proposed project.

(II) Activity 1) Construction, operation or decommissioning of the project involving actions, which will cause physical changes in the locality (topography, land use, changes in water bodies, etc.) Details thereof (with approximate Information/Checklist S.No Yes/No quantities/rates wherever possible) with source confirmation of information data 1.1 Permane nt or temporary change Yes The existing land use will be changed to industrial in landuse, land cover or activity with proposed power plant. The site is topography including increase in approx. 1.5 km from NH-38 connecting with a kacha intensity of landuse (with respect road of approx. 3.5m width. The land consists of to local landuse plan) minor hills & valleys with areas covered with tea plantation. 1.2 Clearance of existing land, Yes There are no b uildings/ structures existing in the vegetation and buildings? proposed land area. The site is covered with partly tea plantations & other vegetation which needs to be cleared as per the plant requirements 1.3 Creation of new land uses? Yes The site is proposed for Coal based Thermal power plant by Assam Power Generation Corporation Limited (APGCL). 1.4 Pre -construction investiga tions’ e.g. Yes Geo -technical investigation of the site w ill be bore holes, soil testing? carried out while setting up the plant. 1.5 Construction works? Yes Structural construction works will be carried out to accommodate Boiler, Turbine, Generator, and Condenser, Cooling water system, Coal conveyor belts, Switchyard and other civil, mechanical and electrical plant and equipment. 1.6 Demolition works? No No dem olition work 1.7 Temporary sites used for Yes Temporary shelters and sanitation facilities for construction works or housing of construction workers shall be provided within plant construction workers? area. 1.8 Above ground buildings, structures Yes As mentioned in the ite m 1.5 or earthworks including linear structures, cut and fill or excavations 1.9 Underground works including No No mining or Tunneling. mining or tunneling? Coal conveying belts, water piping and cables for infrastructure, etc. 1.10 Reclamation works? Yes Coal based thermal power project will be established. 1.11 Dredgin g? No Not applicable 1.12 Offshore structures? No Not applicable 1.13 Production and manufacturing Yes Process Description as presented as Annexure 5 processes? 1.14 Facilities for storage of goods or Yes Storage area for materials will be pr ovided as per materials? the requirement. Coal: Proposed yard at Site, Oil: For the startup operations, proposed tanks at site.

3 Details thereof (with approximate Information/Checklist S.No Yes/No quantities/rates wherever possible) with source confirmation of information data 1.15 Facilities for treatment or disposal Yes ETP & WTP will be provided to collect waste water of solid waste or liquid effluents? from process and domestic activities of plant area for treatment and re-use. No increase in the domestic waste generation is anticipated. Dry ash handling systems are proposed for evacuation of fly ash in dry form through vacuum/ pressurized pneumatic system. The fly ash shall be utilized for manufacturing of cement and other uses. The ash from bottom ash hopper would be passed through clinker grinders and the slurry would be pumped to disposal area using jet pumps. 1.16 Facilities for long term housing of Yes Long term housing colony for workers of the power operational workers? plant are planned in the project complex 1.17 New road, rail or sea traffic during Yes The proposed project will have internal and construction or operation? external roads linked from project site to the coal fields and rail network as well. 1.18 New road, rail, air, waterborne Yes As mentioned in the item 1.17 or other transport infrastructure including new or altered routes and stations, ports, airports etc? 1.19 Closu re or diversion of existing No Not Applicable transport routes or infrastructure leading to changes in traffic movements? 1.20 New or diverted transmission lines Yes One number, double circuit 400kV transmission or pipelines? lines proposed for the from power station switchyard up to Mariani EHV sub-station from the proposed generating power plant. The distance of this sub-station from power house site is around 250 Km. One 400kV switchyard will be constructed in the proposed power plant for evacuation of power. 1.21 Impoundment, damming, No Not envisaged culverting, realignment or other changes to the hydrology of water courses or aquifers? 1.22 Stream crossings? No Nil 1.23 Abstraction or transfers of water No The water requirement for the plant including from ground or surface waters? cooling water make-up to cooling tower, plant cycle make-up, potable and service water, etc would be met from the surface source viz., river Buridihing by pumping water from approx. 14kms away from project site. Permission letter from

4 Details thereof (with approximate Information/Checklist S.No Yes/No quantities/rates wherever possible) with source confirmation of information data Water Resource Department, Govt. of Assam for withdrawal of water @ 3300 cum per hour from Buri-Dihing River already obtained (Requirement - 2500 cum per hour) 1.24 Changes in water bodies or the No Nil land surface affecting drainage or run-off? 1.25 Transport of personnel or materials Yes Transportation is required for labour from nearby for construction, operation or villages and construction materials for the project. decommissioning? 1.26 Long -term dismantling or No Not applicable decommissioning or restoration works? 1.27 Ongoing activity during No Not envisaged decommissioning which could have an impact on the environment? 1.28 Influx of people to an area in either Yes During the construction activities of the power temporarily or permanently? plant, the influx of temporary workers from nearby villages is expected. 1.29 Introduction of alien species? No No Introduction of alien species 1.30 Loss of native species or genetic No No loss of native species or g enetic diversity diversity? 1.31 Any other actions? No None

2) Use of Natural resources for construction or operation of the Project (such as land, water, materials or energy, especially any resources which are non-renewable or in short supply) Details thereof (with approximate Yes/ S. No Information/Checklist confirmation quantities/rates wherever possible) with source No of information data 2.1 Land especially undeveloped or Yes The available land for the propos ed project is agricultural land (ha) undeveloped. 2.2 Water (expected source & Yes Source of water River Burid ihing , competing users) Quantity: 2100 Cum/ Hour. Annexure 6: Water balance diagram 2.3 Minerals (MT) Yes Raw material Coal : 1.83 Million MTA at 80% PLF 2.4 Co nstruction material – Cement, Yes Raw materials for the construction of the proposed steel, stone, aggregates, sand/soil station such as stone aggregate, conforming to IS- (expected source – MT) 383 and sand free of silt meeting the requirements of IS-650 will be obtained from nearby area. Cement will be available from Cement Plants in the State. Steel will be made available from the nearest steel stockyard

5 Details thereof (with approximate Yes/ S. No Information/Checklist confirmation quantities/rates wherever possible) with source No of information data 2.5 Forests and timber No There is no requirement of Timber for this project (Source – MT) except for the office furniture. 2.6 Energy including electricity & fuels Yes Fuel: 1. 83 Million MT A Coal from North Eastern (source, competing users) Coalfields Ltd (NECL) Unit: Fuel (MT) Electricity: 2 MW Energy (MW) 2.7 Any other natural resour ces (use No No Natural Resources would be used except appropriate standard units) mentioned in item No 2.5 for construction purpose.

3) Use, storage, transport, handling or production of substances or materials which could be harmful to human health or the environment or raise concerns about actual or perceived risks to human health Details thereof (with approximate Quantities/ Information/ Yes/ S. No rates wherever possible) with source of Checklist confirmation No information data 3.1 Use of substa nces or materials, which No No major hazardous materials will be used are hazardous (as per MSIHC rules) to human health or the environment (flora, fauna, and water supplies) 3.2 Changes in occurrence of disease or No No diseases are anticipated due to the affect disease vectors (e.g. insect or proposed project water borne diseases) 3.3 Affect the welfare of people e.g. by No Improve living conditions of the local people changing living conditions? and quality of life (QOL) 3.4 Vulnerable g roups of people who could No All pollution control norms will be strictly be affected by the project e.g. hospital followed with respect to Particulate Matter

patients, children, the elderly etc. (PM), SO 2 and NOx emissions by installation of pollution control equipments. Hence the

emissions like SO 2 and Particulate Matter are maintained below the standards and low emissions of NOx from the stacks. The NOx Emissions will be controlled by pollution control equipments like a lean burn system which limits the NOx emission. There is no effect envisaged for the vulnerable groups of people who could be affected by the project. 3.5 Any other causes No No other causes envisaged

4) Production of solid wastes during construction or operation or decommissioning (MT/month) Details thereof (with approximate Information/ Yes/ S. No quantities/rates wherever possible) with Checklist confirmation No source of information data 4.1 Spoil, overburden or mine wastes Yes Excavated soil 4.2 Ash/Municipal waste (d omestic and or Yes Ash % in coal: 6% to 15% commercial wastes) Total Ash produced: 32 TPH Bottom Ash (25% - Design Condition): 8 TPH Fly Ash (90% - Design Condition) : 29 TPH as considering calorific value of 5500 Kcal/kg. No commercial waste, perhaps certain amount of domestic waste will be generated 4.3 Hazardous wastes (as per Hazardous Yes The Hazardous wastes generated from the Waste Management Rules ) proposed project will be complied with the hazardous wastes (management and handling) Rules-2008 with all the latest amendments. Spent Lubricant will be stored in containers and disposed as per norms. 4.4 Other industrial process wastes No There will not be any other industrial process wastes generated from the proposed plant except the wastes mentioned in section 4.2. 4.5 Surplus product No There is no surplus product generation. 4.6 Sewage sludge or other sludge from Yes Not significant and Sludge generated from the effluent treatment STP will be used as manure to the plants. 4.7 Construction or demolition waste Yes During construction some amount of construction debris may be generated which will be segregated and the recyclables would be sold to authorized recyclers. The remaining waste will be used for land disposable and development of internal roads, boundary walls, etc. 4.8 Redundant machinery or equipment No Most of the equipment used for the construction will be hired. 4.9 Contaminated soils or other materials Yes Detoxified containers and container lining of hazardous waste and chemicals shall be disposed off to the authorized agencies of SPCB 4.10 Agricultural wastes No Not Envisaged 4.11 Other solid wastes No No other solid wastes

5) Release of pollutants or any hazardous, toxic or noxious substances to air (Kg/ hr) Details thereof (with approximate Yes/ S.No Information/ Checklist Confirmation quantities/ rates wherever possible) with No source of information data 5.1 Emissions from combustion of fossil Yes The pulverised coal will be used for Boiler fuels from stationary or mobile sources and flue gas emission details are given below. Flue gas emission: SPM: Less than 100 mg/Nm 3 SO2: Less than2000 mg/Nm 3 for first 500 MWe. NOx: 750 mg/Nm 3 (Based on World Bank Norms) 5.2 Emissions from production processes Yes As mentioned in the Item # 5.1 5.3 Emissions from materials handling Yes Fugitive emissions to limited extent including storage or transport 5.4 Emissions from construction activities Yes Temporary in nature which may originate including plant and equipment during construction of building which will be taken care by proper dust suppression like sprinkling of water. 5.5 Dust or odors from handling of Yes Dust generated due to handling construction materials including construction material will be controlled by sprinkling of materials, sewage and waste water. 5.6 Emissions from incineration of waste No No incineration is proposed 5.7 Emissions from burning of waste in No No material will be openly burnt in air. open air (e.g. slash materials, construction debris) 5.8 Emissions from any other sources No Emissions from other sources are not envisaged

8 6) Generation of noise and vibration and emissions of Light and Heat: Details thereof (with approximate quantities/ Yes/ S.No Information/Checklist confirmation rates wherever possible) with source of No information data 6.1 From operation of equipment e.g. Yes i) Noise will be generat ed during operation of engines, ventilation plant, crushers generator, Turbines, compressors, pumps, fans, etc. The expected noise level during those operations is 85 dB (A), necessary PPEs (Ear Muffs, closed chambers) will be provided for the personnel working in those areas. Noise level will be limited as per CPCB’s Ambient Noise Standards/ MoE&F notification on Noise Pollution (Regulation and control) Rules 2000 & OSHA Standards. Suitable acoustic enclosures will be provided to control the noise level. ii) Most of the equipment structures are static. The vibration effect of these will be only local and the design of supports and foundations will nullify the intensity of vibration. iii) Light emissions are not envisaged in the project. iv) Heat emissions will be felt nearby boiler, generator areas. 6.2 From industrial or similar processes Yes As explained in section 6.1. 6.3 From construction or demolition Yes Noise generated from drilling , dismantling and welding will be temporary. 6.4 From blasting or piling No No blasting or Piling is en visaged 6.5 From construction or operational traffic Yes During the construction activities care will be taken to control the noise within the standards. While operation, traffic will contribute some noise level. 6.6 From lighting or cooling systems Yes All equipment in the Coal fired Plant will be designed to have a total noise level not exceeding 85 dB(A) at a distance of 1 meter and Cooling Tower: 65 dB(A) 6.7 From any other sources No No other sources envisaged

9 7) Risks of contamination of land or water from release of pollutants into the ground or into sewers, surface waters, ground water, coastal waters or the sea Details thereof (with approximate Yes/ S.No Information/Checklist confirmation quantities/ rates wherever possible) with No source of information data 7.1 From handling, storage, use or spillage Yes Limited to dyke area of hazardous materials 7.2 From discharge of sewage or other Yes ETP and STP will be pro vided to collect waste effluents to water or the land (expected water from all the sources of plant area and mode and place of discharge) treated to re-use as far as possible. 7.3 By deposition of pollutants emitted to No The major emission s from the proposed

air, into the land or into water project are Particulate Matter (PM), SO 2 and NOx. Adequate control systems like ESP and stack height meeting MoE&F guidelines will be provided to control the emissions. Hence there will not be any chance of contamination of land and water by deposition of pollutants emitted into air. 7.4 From any other sources No No other sources 7.5 Is there a risk of long term build up of Yes But within the prescribed limits by proper pollutants in the environment from these Environmental Management Plan (EMP), Long sources? term risk of pollutants can be minimized.

8) Risk of accidents during construction or operation of the project, which could affect human health or the environment Details thereof (with approximate Yes/ S.No Information/Checklist confirmation quantities/ rates wherever possible) with No source of information data 8.1 From explosions, spillages, fires etc ., from No Only minimum quantity of the chemicals storage, handling, use or production of required will be stored within the plant hazardous substances premises and safety precautions will be taken while handling. 8.2 From any other sources No Adequate safety measures will be taken 8.3 Could the project be affected by natural No It i s situated in earthquake zone -V as defined disasters causing environmental damage in IS: 1893-2002. (e.g. floods, earthquakes, landslides, cloudburst etc.)?

9) Factors which should be considered (such as consequential development) which could lead to environmental effects or the potential for cumulative impacts with other existing or planned activities in the locality Details thereof (with approximate quantities/ Information/ Yes/ S. No rates wherever possible) with source of Checklist confirmation No information data 9.1 Lead to development of supporting facilities, No Ancillary building such as service building, ancillary development or development electrical switchgear room building etc., shall stimulated by the project which could have be provided. These buildings shall generally be impact on the environment e.g. constructed of RCC frame work within filled Housing development brick work. Service building shall be separated Extractive industries from Main TG building, atleast by 10 to 20 feet Supply industries with partition wall to avoid Noise. However, Others the impact on environment if any will be controlled by proper EMP. 9.2 Lead to after -use of the site, which could No Not Envisaged have an impact on the environment 9.3 Set a precedent for later developments Yes Development of local community Improvement in Quality of life Ecological balance by sustainable development 9.4 Have cumulative effects due to proximity to Yes To avoid cumulative effects due to planned other existing or planned projects with similar projects with similar effects, at the time of effects. issue approvals, a minimum distance from one unit to other unit will be maintained as per MOEF siting guidelines.

11 (III) Environmental Sensitivity Name/ Aerial distance (within 15 km.) S.No Areas Identity Proposed project location boundary 1 Areas protected under international No None in the study area conventions, national or local legislation for their ecological, landscape, cultural or other related value 2 Areas which are important or sensitive for Tipang RF ~6 km E ecological reasons - Wetlands, watercourses or Tamdang RF ~9 km SSW other water bodies, coastal zone, biospheres, Tirap RF ~12 km ENE mountains, forests. Kotha RF ~9 km NE Uppar Dihing ~10 km NW RF 3 Areas used by protected, important or sensitive No There are no notified areas used by species of flora or fauna for breeding, nesting, sensitive species of flora & fauna in foraging, resting, over wintering, migration the study area 4 Inland, coastal, marine or underground waters Buridihing ~6 km NW river 5 State, National boundaries Arunachal ~2.5 km S Pradesh State 6 Routes or facilities used by the public for access to No None in the study area recreation or other tourist, pilgrim areas 7 Defence installations No None in study area 8 Den sely populated or built -up area Margherita ~16km W town Parbatipur ~6 km NE Gaon ~5km W Ledo 9 Areas occupied by sensitive man -made land Yes Most of the villages in the study area uses (hospitals, schools , places of worship, have education & electricity facilities community facilities) but very few have health centers 10 Areas containing important, high quality or No None in the study area scarce resources (ground water resources, surface resources, forestry, agriculture, fisheries, tourism, minerals) 11 Areas already subjected to pollution or No None environmental damage. (those where existing legal environmental standards are exceeded) 12 Areas susceptible to natural hazard which could No The project area is situated in cause the project to present environmental earthquake zone-V as defined in problems (earthquakes, subsidence, landslides, IS: 1893-2002 erosion, flooding or extreme or adverse climatic conditions)

13 Annexure -1 Plant Layout

14 Annexure 2 Topographical Map - 10km radius

15 Annexure 3 Google Earth Image

16 Annexure 4 Contour Map

17 Annexure 5

Process Description

18 Annexure 6

Water Balance Diagram

PRE FEASIBILITY REPORT FOR 1X 660 MW SUPERCRITICAL MARGHERITA THERMAL PROJECT, DISTRICT-TINSUKIA, ASSAM

ASSAM POWER GENERATION CORPORATION LIMITD Regd. Office: Bijulee Bhawan, 3rd floor, Paltanbazar, Guwahati-781 001, Assam Tele-Fax: 0361-2739546;

PRE FEASIBILITY REPORT FOR 1X 660 MW SUPER CRITICAL MAR GHERITA THERMAL PROJECT, DISTRICT-TINSUKIA, ASSAM

CONTENTS

Section Description

1 Project Highlights

2 Executive Summary

3 Introduction

4 Demand Analysis

5 Site Selection Study

6 Selection of Super Critical Technology

7 Technical Features of the Main Plant Equipments

8 Technical Features of Balance of Plants

9 Environmental Considerations

10 Execution and Project Management

11 Clean Development Mechanism (CDM)

12 Project Cost Estimate

13 Conclusion

14 Drawing list and drawings

ASSAM POWER GENERATION CORPORATION LIMITED 1 THIRD FLOOR,BIJULEE BHAWAN,PALTAN BAZAR,GUWAHARI-01,ASSAM

PRE FEASIBILITY REPORT FOR 1X 660 MW SUPER CRITICAL MAR GHERITA THERMAL PROJECT, DISTRICT-TINSUKIA, ASSAM

SECTION – 1

PROJECT HIGHLIGHTS

1.0 Project Information & Location

1.1 Project Margherita Thermal Power Project

1.2 Plant capacity 1 x 660 MW

1.3 Promoter Assam Power Generati on Corporation Limited (APGCL)

1.4 Plant site location Villages: Saliki NC,Lekhapani

Tehsil: Makum Mouza, Margherita Revanue Circle.

District: Tinsukia,State: Assam

1.5 Location co-ordinates 95 0 48’49. 4’’E Longitude 27 0 18’ 38.2’’ N Latitude 1.6 Nearest Town Margherita (~16 Km)

1.7 Major Town & City Tinsukia city (~55 Km)

1.8 State Capital Dispur, Guwahati (~550 Km)

1.9 Nearest Railway Station Ledo (~ 8), Lekhapani (~4 Km)

1.10 Nearest Airport Dibrugarh Ai rport (~100 Km)

2.0 Meteorically Condition

2.1 Climate Humid and tropical - A hot and humid pre - monsoon from March to mid May, a prolonged southwest monsoon or rainy season from mid May to September, a pleasant post-monsoon or retreating monsoon from October to November and a cold pleasant winter from December to February 2.2 Site Elevation ~ varying from around 150 m to 236 m from eastern side to western side above Mean Sea Level

2.3 Annual Maximum Mean 31.4ºC Temperature

ASSAM POWER GENERATION CORPORATION LIMITED 2 THIRD FLOOR,BIJULEE BHAWAN,PALTAN BAZAR,GUWAHARI-01,ASSAM

PRE FEASIBILITY REPORT FOR 1X 660 MW SUPER CRITICAL MAR GHERITA THERMAL PROJECT, DISTRICT-TINSUKIA, ASSAM

2.4 Annual Minimum Mean 8.8 ºC Temperature 2.5 Design ambient temperature for 50 ºC Continuous rating of Electrical 2.6 Relativeequipments. Humidity 88%

2.7 Average rain fall ~2600 mm

2.8 Basic design wind pressure As per IS: 875 (Latest Edition)

2.9 Seismic zone Zone-V

2.10 Maximum wind velocity 2.8 m/sec

3.0 Fuel Source and Consumption for 1 x 660 MW

3.1 Source of Fuel 100% indigenous Mergherita Coal from nearby North Eastern Coalfields Ltd (NECL) 3.2 Grade G2 Grade (5500-6500 Kcal/kg)

3.3 Gross Calorific value 5500 Kcal/kg

3.4 Boiler fuel consumption 209 TPH

3.5 Boiler fuel consumption at 80 % 1.83 PLF(Million tones/annum) 3.6 Coal storage days at site 15 days

3.7 Support Fuel & Source Heavy Furnace Oil (HFO)/Light Diesel Oil (LDO) from nearest refinery at Digboi.

3.8 Support fuel required (HFO /LDO) 3725 KL per annum 4.0 Ash Generation

4.1 Ash % in coal 6% to 15%

4.2 Ash generation in the boiler 32 TPH

5.0 Water Source and Quantity

5.1 Source of water The Make -up Water Requirement shall be met from “Buridihing River” by Pumping water from approx. 14 Kms away from the Project site.

5.2 Raw water requirement 2100 m 3/hr (Water drawal permission obtained for 3300 m3/hr) 6.0 Land requirement 575 Acres (Land allotted 661 acres)

ASSAM POWER GENERATION CORPORATION LIMITED 3 THIRD FLOOR,BIJULEE BHAWAN,PALTAN BAZAR,GUWAHARI-01,ASSAM

PRE FEASIBILITY REPORT FOR 1X 660 MW SUPER CRITICAL MAR GHERITA THERMAL PROJECT, DISTRICT-TINSUKIA, ASSAM

7.0 Plant Equipment

7.1 Boiler Pulverized Coal firing Boiler (PC)

7.2 Boiler type Steam generator will be Once Through sliding pressure supercritical boiler, Vertical wall evaporator with rifle tubing, Conventional Two-pass, Radiant reheat, Balanced draft and drumless type unit designed for firing Indian coal as prime fuel

7.3 Steam Parameters per Boiler Flow – 2225 TPH ,Pressure – 256 ata , Temperature – 568± 5oC 7.4 Boiler efficiency 88%

7.5 Turbine Steam turbine will be a horizontally split, multi cylinder (HP, Two IP, Two LP) 3000 rpm multistage, Tandem compound, single reheat, condensing type unit uncontrolled extractions for regenerative feed heating with suitable to generate the 660000 KW at 21 KV, Hydrogen cooled alternator

7.6 Turbine type Impulse cum reaction

7.7 Turbine speed 3000 RPM

7.8 Electrical Generator Two -pole, hydrogen -cooled turbo generator with direct water cooling for the stator winding, which is directly coupled to the turbines, a rotating-diode brushless excitation system, 50 Hz., 3 phase, 0.85 power factor (lagging), 21 kV 7.9 Plant Heat Rate 2186 Kcal/KWh

7.10 Coal handling design capacity 1500 TPH for 14 hours operation with Two (2) Streams (1W + 1S) 7.11 Bottom ash handling system Den se Phase Pneumatic System - semi wet extraction and wet slurry disposal 7.12 Fly ash handling system Dense Phase Pneumatic System –Dry extraction with dry disposal 7.13 Cooling tower type Induced Draft Cooling Tower

7.14 No. of Cooling tower One

7.15 Capacity 69000 m 3/hr

7.16 Chimney One twin flue gas path

ASSAM POWER GENERATION CORPORATION LIMITED 4 THIRD FLOOR,BIJULEE BHAWAN,PALTAN BAZAR,GUWAHARI-01,ASSAM

PRE FEASIBILITY REPORT FOR 1X 660 MW SUPER CRITICAL MAR GHERITA THERMAL PROJECT, DISTRICT-TINSUKIA, ASSAM

7.1 7 Height of chimney 275 Meter

7.1 8 Flue Gas Desulphurization Wet type

8.0 Project Schedule 48 Months

9.0 Man Power Requirement

9.1 During Construction Phase 175 personnel

9.2 During O & M 600 personnel

10. Annual Power Generation

10.1 Gross Generation at 100% PLF For 1 x 660 MW – 5781.6 million kWh

10.2 Gross Generation at 80% Plant PLF For 1 x 660 MW – 4625.28 million kWh

10.3 Auxiliary Consumption for 660 277.517 million kWh(80% PLF) MW @ 6% (per annum)

11.0 Costing

11.1 Total project cost Rs. 4383.98 crores

11.2 Interest during construction Rs. 763.54 crores

11.3 Total project Cost with IDC and Rs. 5278.20 crores Contingency 11.4 Total Project cost per MW Rs.crores 8.00 crores

11.5 Cost of generation @ 85% PLF Rs.3.401 / Unit on 1st year 11.6 Le vellised cost of generation @ Rs. 3.220 / Unit 85% PLF

ASSAM POWER GENERATION CORPORATION LIMITED 5 THIRD FLOOR,BIJULEE BHAWAN,PALTAN BAZAR,GUWAHARI-01,ASSAM

PRE FEASIBILITY REPORT FOR 1X 660 MW SUPER CRITICAL MAR GHERITA THERMAL PROJECT, DISTRICT-TINSUKIA, ASSAM

SECTION - 2

EXECUTIVE SUMMARY

2.1.0 Electricity is the prime mover of growth and is vital to the sustenance of a modern economy. The growth of the Indian Economy depends heavily on the performance and growth of the power sector as the Indian power sector contributes 10.17% in its Index of Industrial Production (IIP) and has grown at a significant rate since independence. Total generation capacity of the country, which was 1362 MW at the time of independence, has increased to about 181500 MW in the last six decades. During the year 2010 - 11, the country faced an energy shortage of 73,236 MU (8.5%) and a peak shortage of 12,031 MW (9.8%). Therefore, it is endeavor of the government to ensure that agriculture, industry, commercial establishments and households receive uninterrupted supply of electricity at affordable rates. The total capacity addition during the past 30 years between the 6th and the 11th Five Year Plans was approximately 143,000 MW. A total capacity addition of 76,000 MW is planned for the 12th Five Year Plan (2012-17) which should result in substantial investments in the power generation sector. The incremental increase of 41 GW is up to 31st March, 2011. Further, demand for energy grows in tandem with the growth of the economy. It is anticipated that annual growth rates of electrical energy consumption(utilities) would be 12.19% at the end of 13th Plan compared to the growth rate of10.52% at the end of 12th Plan (2012 - 2017).

In order to accelerate growth in the state, particularly in the industrial sector under the open economic policy the state government is planning a number of initiatives including investment subsidies, tax holiday etc. In the energy sector, major steps have been taken to support the accelerated industrial growth and enhanced production in the agricultural sector. The industrial development in the state till date has only been nominal mainly due to lack of industrial infrastructure. Non availability of sufficient electric power has been one of the greatest deterrents to the growth of industry and agriculture in the State of Assam. Efforts are being made to promote industries in mineral rich areas of the state as well as in the agro-based sector.

Assam possesses immense potential for development of the power sector. However, despite being a storehouse of power, ranging from hydel to natural gas including oil and coal resources, the progress of this sector in Assam has not taken place on a scale commensurate with the possibilities. As a result, there exists a big gap between availability and demand for power in the state. Assam accounted for only a small fraction i.e. 0.16 per cent of the total generation of electricity in the country during 2000-2001

The proposed power plant consisting of following Major equipments and detailed descriptions for equipments are described in section – 7 and section – 8

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2.2.0 Steam Generating Unit

The steam generator will be sliding pressure supercritical, once-through type, utilizing a

Tangential Firing System for NO X control. Boiler is a single reheat, variable pressure operation, with balanced draft furnace conditions. The unit is capable of firing the range of pulverized coals as a Main fuel. The steam generating unit for 660 MW will be sized for 2225 TPH steam flow at, 256 ata steam pressure and 568 ± 5 °C main steam temperature, 595 ± 5°C reheat temperature with at 100% MCR Super heater outlet with design consideration of indigenous coal. This will ensure adequate margin over the requirement of Turbine at 100% MCR to cater for auxiliary steam. The steam generator would be capable of maintaining main steam and hot reheat steam temperatures of designed value between 60-100% MCR load or better. The steam generator would be capable of operation with ‘the HP heaters out of service’ condition and deliver steam to meet Turbo-generator requirement at 100% MCR. The steam generators are coal fired with Heavy Fuel Oil firing (HFO) provision upto 30% Boiler Maximum Continuous Rating (BMCR) for low load operation & flame stabilization and Light Diesel Oil (LDO) firing provision to a maximum of 10% BMCR as secondary fuel and start-up fuel respectively.

2.2.1 Boiler Feed Pumps and Drives

Four (4) nos. of Boiler feed pumps are envisaged for the unit. Two numbers (2 x 50%) capacity Turbine Driven Feed Pumps (TD-BFP) shall be provided for each unit for normal working along with 2 X 30% Motor Driven Feed Pumps (MD- BFP) as stand by and start up purpose are envisaged.

2.2.2 Electrostatic Precipitator

The steam generating unit shall be installed with Six (6) Electrostatic Precipitators comprising ten (10) bus sections in the direction of gas flow and two (2) bus sections perpendicular to the gas flow.

2.2.3 Flue gas desulphurization unit:

Global environmental problems are drawing large attention in these days. Among these SOx emission has become a major issue and consequently the importance of Flue Gas Desulphuhzation (FGD) technology, as a counter- measure for this problem is becoming greater. The Flue-gas desulphurization (FGD) or SO2 scrubbing processes typically uses calcium or sodium based alkaline reagent. The reagent is injected in the flue gas in a spray tower or directly into the duct. The SO2 is absorbed, neutralized and/or oxidized by the alkaline reagent into a solid compound, either calcium or sodium sulphate. The solid is removed from the waste gas stream using downstream equipment. Scrubbers are classified as "once through" or "regenerable" based on how the solids generated by the process are handled. Once through system either dispose of the spent sorbent as a ASSAM POWER GENERATION CORPORATION LIMITED 7 THIRD FLOOR,BIJULEE BHAWAN,PALTAN BAZAR,GUWAHARI-01,ASSAM

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waste or utilize it as by-product. Regenerable systems recycle the sorbent back into the system. Flue Gas from the boiler is induced Into the FGD plant by ID fans. Total gas pressure loss in the FGD plant is compensated by ID fans. Bypass duct is provided to permit isolation of FGD plant or flexible operation of boiler and FGD plant. A high sealing efficiency damper is provided at the bypass duct of each FGD plant. A damper is provided at the FGD Inlet duct. Similarly a damper is provided at the FGD outlet duct. Seal air fans are installed for every damper

2.3.0 Steam Turbine Generator (STG )

The steam turbine of 660 MW, will be a horizontally split, multi cylinder (HP, Two IP & Two LP) 3000 rpm multistage, tandem compound, single reheat, condensing type unit uncontrolled extractions for regenerative feed water heating. The turbine will be designed for main steam parameters of 247 ata, 565 0C at emergency stop valves of H.P. turbine. The LP turbine will exhaust against condenser pressure of about 0.1 ata (refer HMBD). The Turbo-generator set will be designed for a maximum throttle steam flow at Turbine Valve Wide Open (V.W.O.) condition of about 105% of Turbine MCR condition. The turbine will be rated for a minimum of 660 MW and shall be capable of both constant variable pressure operations as well as with HP heater out.

2.3.1 Condensing Equipment

One (1) no. of Double pass surface condenser, having different back pressures will be provided per L.P Turbine with cooling water side of condensers in series with adequate hot well capacity capable of maintaining the required vacuum while condensing steam at the maximum rating of the turbine, will be provided. The condenser is of box type construction with divided water box design and is provided operation of one half of the condenser while the other half is under maintenance. The steam space will be rectangular cross-section. The condenser is provided with integral air cooling section from which air and non- condensable gases are drawn out with the help of air evacuation equipment.

2.4.0 Generator

The Synchronous generators shall be totally enclosed, horizontal shaft driven directly by steam turbine at 3000 rpm. The generator shall be cylindrical rotor, continuously rated for the turbine outputs and rated at a minimum of 660MW, 0.85 (lagging power factor, delivering power at 21 kV 3 phase, 50 Hz star connected, in IP-54 enclosure. The generator will be provided with brushless excitation. The generators will be capable of operating in isolation or in parallel with the power grid, with voltage variations of ±5% and frequency variations of 47.5 to 51.5 Hertz. No load short circuit ratio of the generator at rated KVA and voltage will be about 0.49. The generator will have Class-F insulation with temperature rise limited to class`B’ limits and shall be

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hydrogen cooled. The inlet temperature of cooling water to the hydrogen coolers will be 33 degree C for design purpose.

2.5.0 Coal Handling System 2.5.1 Coal Requirement

The Coal requirement for the project will be 209 TPH which has been arrived based on firing the 100% Indian Coal having GCV of 5500 kcal/kg & the plant heat rate 2186 kcal/kwh. The annual coal consumption shall be 1.83 Million Tons at 80% PLF.

Coal from the mine areas need to be transported to project site by railway wagons. Broad gauge railway line from Ledo station upto the project site need to be investigated and new lines from mines to the project site need to be installed for transportation of coal. Railway line in Ledo station to coal fields may be augmented/modified as required for transportation of coal. Inside the plant boundary, railway siding shall be provided along with necessary Wagon Tippler arrangement for unloading of coal. The daily requirement will result in to about one rake to two rake of coal comprising each rake having 58 wagons with coal carrying capacity 58 Tons per wagons (i.e. 3364 Tons). Daily coal requirement at full load is 5016 Tons and 15 days requirement of uncrushed coal would be maintained in the plant.

2.6.0 Ash Handling System

The ash handling system is designed to meet the following parameters:

Table 2.1 Coal consumption at full load 209 TPH Ash content in coal (worst) for design 15% Total ash produced 32 TPH Bottom Ash (25% - Design Condition) 8 TPH Fly Ash (90% - Design Condition) 29 TPH

Dense Phase Pneumatic Ash handling system is envisaged with dry form for bottom ash. Ash would be handled in dry condition, and the system would be equipped with arrangement for dry disposal through Silos by truck. Since the sulphur content in NEC/Margherita coal is very installation of de-sulphurisation process in the Power Plant is become mandatory. For that wet type LSFO FGD technology is envisaged for this project. Due to lower life cycle cost and capability of burning of high sulphur coal and high SO2 removal with at least 95% efficiency of SO2 removal from the fly ash wet type LSFO FGD technology is considered. The Flue-gas desulphurization (FGD) or SO2 scrubbing processes typically uses calcium or sodium based alkaline reagent required for

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removal of sulphur be will be received from mines by road. The reagent is injected in the flue gas in a spray tower or directly into the duct. The SO2 is absorbed, neutralized and/or oxidized by the alkaline reagent into a solid compound, either calcium or sodium sulphate. The solid is removed from the waste gas stream using downstream equipment.

2.7.0 Plant Water System

The Composite Water System shall be designed for economical utilization of water for the power plant. The water consumption for the plant is estimated to 2100 M3/hr. The make-up water shall be met from Buridihing River. The intake site is approximately 14 Km away from project site. For process use raw water will be clarified and filtered and sent to DM plant. For potable and non critical process filtered water would be used after sterilization.

Re-circulating cooling water system deploying semi-open recirculating cooling circuit with wet type induced draft cooling tower would be used with clarified river water as coolant.

Sweet water requirement for process and potable use would be met by filtered raw water tank.

The DM water requirement for heat cycle make up would be met from the De- mineralization plant.

2.8.0 Cooling Towers (CT)

One (01) no. of the induced draft type cooling tower shall be provided for the unit. The cooling tower will discharge the recooled circulating water to CW pump house circulating water sumps.

Number of cooling towers : One number

Type of cooling tower : Induced Draft.

Design inlet circulating water flow rate : 69,000 m 3/hr

Cooling range of circulating water : 10 0C

Ambient wet-bulb temperature : 26.40 0C (for CT design)

Circulating water makeup : Clarified water

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SECTION - 3

INTRODUCTION

3.1.0 Introduction

There has been substantial growth in demand of electric energy for domestic, industrial, agricultural and commercial consumption in Assam in the past decade. In order to sustain the intended development in agriculture & industry an increased demand for electrical supply is foreseen.

The responsibility of generation of power in the state, at present, lies with the Assam Power Generation Corporation Limited (APGCL) which came into existence after disbanding of ASEB in Dec’ 2004 through State Power Sector Reform Program under the provision of Electricity Act’ 2003. APGCL is a state owned Successor Company and inherited the generating stations of ASEB. It is entrusted with the task of power generation in the power starved state of Assam along with the daunting task of developing new power projects with low allocation of natural resources required for power generation.

APGCL has at present installed capacity of 439.7 MW. APGCL is operating the following power stations:

3.2.0 Projects under operation

Table 3.1

Sl. Name capacity No.

1 Namrup TPS (Gas based) 134 MW (effective 119.5 MW )

2. Lakwa TPS (Gas based) 157.2 MW

3. Karbi Langpi Hydro Power Station 100 MW

4 Myntriang small hydro project. Stage-II 2x1.5 MW

5 Chandrapur TPS (Oil based) 60 MW (under suspended Operation) Now under revival process.

Total installed capacity 439.7 MW

APGCL has also taken up the following projects which are under stages of execution.

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3.3.0 Projects under development

Table 3.2

Sl. Name Capacity (status) No.

1 Namrup Replacement plant 100 MW (Under construction)

2 Myntriang small hydro project. Stage -I 2X3 MW (Under construction)

3 Lakwa Replacement Power Plant 70 MW ( Procurement under process)

4 Lungnit small hydro project. 6 MW (Procurement under process)

5 Lower Kopili HEP 110 MW ( under scrutiny of

CEA)

6 Margherita Power plant 1X660 MW

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SECTION – 4

DEMAND ANALYSIS

4.1.0 India has been facing electricity shortages in spite of appreciable growth in electricity generation. The demand for electrical energy has been growing at the faster rate and shall increase at higher growth rate to match with the projected growth of Indian economy. The ‘per capita’ power consumption figure (209.21 kWh in 2009-10) for the state of Assam stands well below the national average (778.63 kWh). The per capita income (Rs. 33633) is also lower than national average (Rs.60,972) as per 2011-12 statistics released by GOI. In order to accelerate growth in the state, particularly in the industrial sector under the open economic policy the state government is planning a number of initiatives including investment subsidies, tax holiday etc. In the energy sector, major steps have been taken to support the accelerated industrial growth and enhanced production in the agricultural sector. The industrial development in the state till date has only been nominal mainly due to lack of industrial infrastructure. Non availability of sufficient electric power has been one of the greatest deterrents to the growth of industry and agriculture in the State of Assam. Efforts are being made to promote industries in mineral rich areas of the state as well as in the agro-based sector

It may be observed from the statistics of the state grid and the 17th Electric Power Survey (EPS), published by the Ministry of Power, Government of India, that the energy demand/supply position of the state of Assam at the end of the 12th Plan requires substantial capacity addition particularly in thermal sector. The state grid depends mainly on gas and hydel generation and partly on contribution from the Central Sector. The above scenario highlights the need to add base load station to the state grid as a measure to bridge the gap between the demand and supply. In order to induct more base load thermal power stations for stability of the state grid, APGCL has proposed to set up a 1X660 MW Thermal Power Station in Tinsukia district of Assam. The plant will consist of Coal Fired PF Boiler Units, Steam Turbine Generator Units, Coal Handling Plant, Ash Handling Plant, Flue Gas Desulphurisation Units and Balanced of Plant equipments and facilities. The proposed power station at Margherita would use Assam coal as main fuel for the plant. The coal will be sourced from the nearby mines of North Eastern Coal fields. Coal for the station shall be made available from North Eastern Coal Fields which has adequate mineable high sulphur coal reserve to feed the station for the designed life span of thirty (30) years.

The primary function of a power system is to supply its customers with electrical energy as economically as possible with acceptable reliability and quality. Reliability is defined as the ability of the system to satisfy the customer demand with acceptable quality. The balance between the supply of electricity and the demand is quantified using a reliability indicator called the Loss of Load Probability (LOLP). When this indicator is at an appropriate level, called the “generation adequacy standard”, the supply/demand

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balance is judged to be satisfactory. According to State grid codes, the accepted generation adequacy standard is 2% (i.e. for 175 hours in a year the actual load is likely to exceed the available generation). The draft National Electricity Plan (NEP)-2012, stipulates that the accepted generation reliability standard shall be 0.2% (i.e. for 18 hours in a year the actual load may exceed the available generation leading to loss of load events). The present LOLP of Assam is around 40% (meaning 40 % of the time in year system load is exceeding available generation leading to load shedding) which is unacceptable and will go up further if the uncertainty in import is also factored in.

One of the objectives of the National Electricity Policy is to ensure Per Capita availability of electricity to be increased to over 1000 units by 2012.

To fulfill the above objective the state of Assam must have an aggressive program of power generation capacity addition.

4.2.0 JUSTIFICATION OF THE POWER PROJECT

APGCL has not been able to enhance its generation capacity since commissioning of 2X50 MW Karbi Langpi Hydro Electric project in the year 2007. The 100 MW Namrup project is a replacement project which will utilize the existing gas with an efficient combined cycle plant. The 37.2MW Lakwa waste heat recovery project is being retrofitted to the three 20 MW open cycle gas turbines.

The Assam Accord Amguri project has been put into cold storage to an indefinite period due to non availability of gas. The four 15 MW units of Lakwa station has been proposed to be replaced and the procurement process has started. All these plants are running on available gas supply which was contracted decades ago.

Assam being rich in coal reserve, the main fuel for power generation has low per capita power consumption. To bridge the present gap between demand and supply, any capacity addition will be a welcome relief to this power starved state.

The major reasons which have encouraged APGCL to invest in Tinsukia district of Assam are as follows:

• State of Assam has a meager per capita electricity consumption compared to the national average. Accelerated growth in electricity consumption is expected with opening of economy and exploitation of investment potential in the state. Thus new capacity addition will be a welcome move. • State of Assam has only a few coal based thermal power station till date. • Adequate land may be available at a reasonable price near Margherita where population density is low and quality of land is inferior from agricultural point of view.

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• Though land filling will be involved, the necessary soil can be arranged from the reservoir and a terraced layout can be planned. For this proposed project no human habitation, forest area or sanctuary would be encroached. • The major benefit of this area is proximity to major coal fields. • Transportation cost of coal from the mine to the proposed plant will be very low. • Consumptive water will be available from the Buri Dihing River and has low TDS in this stretch. • With infrastructure available in the region, substantial assistance can be availed. • Road connectivity is already available at the moment and will involve augmentation.

With the above in view, it is expected that the energy cost shall be reasonable and market ability of power from the station will be attractive.

4.3.0 Benefits of the Project

Based on the plant model considered for the project, the following benefits may be derived off:

• After the installation of plant Facilities continuous, uninterrupted power will be supplied to the Grid. • The implementation of the project would reduce overall expenditure to meet the energy requirement and power deficit in the state. • The costs per thermal energy made available from the solid fuels are substantially low when compared with liquid fuels.

4.4.0 Government / Statutory Approvals

For setting up a Thermal power project a number of statutory and non-statutory clearances are required. The salient clearances are listed below:

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Table 4.1

S. No Particulars Approval Authority & Status

1. Land availability including Government of Assam, and Ministry of Environment forest Land and Forest (MOEF).

Complete quantum of Land for installation of 1 X 660 MW is available. Total 661 acres of land has been obtained from GoA for the project vide letter no:RSS.1005/2012/19 dtd:06/04/2013

2. Water requirements and its Department: Water Resources Department, Assam. availability The water requirement for the proposed 660 MW super critical thermal power plant has been estimated as 2100 m3 / hr.

The source of water is buridihing river. Water allocation of 3300 M3 / hr was obtained from Water resource Dept. GoA vide letter No. 3. Coal availability & Requirement of Coal is estimated 20 9 Tons per day and transportation 1.83 Million Tons Per Annum (MTPA).

The allocation of coal for the project is requested from nearby coal Mines areas of North Eastern Coalfields Ltd (NECL).

4. Pollution Control Clearance State Pollution control board (SPCB).

(water and Air) For such size of project, APCB in response for Public Hearing.

5. Civil Aviation Clearance for National Airport Authority of India (AAI)

Chimney Height NOC yet to be taken from Airport Authority of India for Construction of 275 M height chimney. Submission of application is under process.

6. Rehabilitation & resettlement Ministry of Forest and Environment (MOEF) and plan State Government. R&R Plan of APGCL has to be approved by GoA.

7. Power absorption & State Electricity Board (SEB) / APDCL / other bulk evacuation plan consumer(s).

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8. Registration of company Registrar of company. Registered under Company

Act 1956 as wholly owned company of Govt. of Assam. 9. Environmental & Forest Environmenta l Impact Assessment study and Clearance from MoEF / State Environmental Public hearing yet to be carried outs. Environment Dept. Environmental Clearance- Process for submission of application is under process.

10. Local Panchayat Union / Local Authority Municipality approval

11. Electrical Approvals Inspector of Electrical department

12. Boiler Approvals Inspector of Boiler and Factories

13. Ash Utilization Plan Ash Utilization plan will be drawn as per MoEF guidelines.

14. Approval by state regulatory As per Electricity Act 2003 , approval of SERC for tariff commission/Central Regulatory within the State and CERC for sale of electricity to more Commission than one state will be obtained at appropriate stage.

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SECTION – 5

SITE SELECTION STUDY

5.1.0 Factors for Site Selection

The following main factors were considered when identifying a site for the Thermal Power Plant.

• Availability of adequate vacant land in possession of APGCL free from R & R Issues. • Availability of adequate water for cooling water & make up requirements. • Non-forest, non-arable, compatible land use availability. • Infrastructural facilities like road and for transportation. • Proximity to nearby sub-stations for power evacuation. • Adequate area for handling disposal / usage of ash • Suitability of soil characteristics for construction . 5.2.0 Site Selection Concept

The selection of site is based on the following factors.

• Adequate un-inhabited, uncultivated non-forest land availability. • General soil characteristics are suitable. • Adequate land availability for ash disposal. • The length of approach road to be constructed is minimum. • Nearer to water source.

5.3.0 Details of Proposed Site and infrastructure

1 x 660 MW Margherita Thermal Power Project is proposed adjacent to the nearby coal mines of North Eastern Coal Fields.

5.3.1 Approach to Proposed Site

The proposed 1 x 660 MW Margherita Thermal Power Project is located near Saliki Village at a distance around 2 km south-west of NH38 in Margherita sub-divisional town of Tinsukia District of Assam. Site is about 16 km from Margherita Town and about 60 km from Tinsukia. Nearest railway station is about 7 – 8 km at Ledo. The Latitude and Longitude of the proposed land are 95 048’49.4’’E & 27 018’38.2’’N. From NH-38 a kachha road of approx. 3.5m width connects the site and the road extends further about 1.5kM up to the abandoned Coal India Ltd.’s road bridge on Lekhapani river supposed to link proposed Lekhapani Coal mines. However, there is dense forest beyond and there is no forest department clearance for further construction. The land consists of hills and

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valleys with areas covered with tea plantations. The entire site has hillocks having peaks varying from 10 – 60 m. There are steep valleys between the hillocks. Southern side of the land is flanked by hillock of approximate height of 100m. Elevation of the site varies from 130 m to 256 m above MSL.

The proposed thermal power plant site can be accessed by road. It is located near Saliki Village around 2 km south-west of NH38 in Margherita sub- divisional town of Tinsukia about 16 km from Margherita Town and about 70 km from Tinsukia. From NH-38 a kachha road of approx. Lekhapani River supposed to link proposed Lekhapani Coal mines. This kachha road needs to be developed during project stage for heavy vehicle movement. The site is connected with Dibrugarh Town by NH-37 via Tinsukia up to Makum and NH-38 from Makum upto Lekkhapani. Further this highway merges into NH- 153 which goes upto Indian Border with Myanmar. The nearest railway station is at Ledo at a distance of about 7 – 8Km connected by broad gauge line from Dibrugarh. Nearest ports are at Kolkata and Haldia in West Bengal.

Land requirement:

Based on the CEA report “Review of land requirement for thermal power projects” September, 2010; the land requirement analysis for 1X660 MW Margherita Super Critical TPP is deliberated and as follows:

Sl No Description Land area in acres

1 Main plant 15

2 Coal handling system 80

3 Water system 18

4 Water reservoir 20

5 Switchyard 10

6 Miscellaneous BOP facilities, stores, roads 28

7 Total (Sl No1 to 5 above) 171

8 Green Belt (1/3 of Sl No 7.) 57

9 Ash disposal area 165

10 Township 100

11 Corridors for ash slurry, raw water and coal 82

12 Grand Total (Sl No 7 to 11 above) 575

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5.3.2 Water requirement & availability

The total raw water requirement is estimated to be 2100 m 3 / hr for the proposed 1 x 660 MW Power plant. Raw water sources for the proposed power plant will be made from Buridihing river which is located 14 Kms (approx.) away from proposed site.

Semi- open circuit re-circulation type of cooling system using clarified water as make-up with Induced draft cooling towers has been proposed for the cooling.

Fuel Availability & transportation

Indigenous cola will be considered as the main fuel for the Proposed 1 X 660 MW power Plant. The coal will be sourced from the nearby mines of Eastern Coalfields Ltd (NECL) near Margherita. There are numbers of mines operating in this coal field. These mines have railway siding and coal from these mines are handled by railway wagon or dumpers. The Coal requirement for the project will be 209 TPH which has been arrived based on firing the 100% Indian Coal having GCV of 5500 kcal/kg & the plant heat rate 2186 kcal/kwh. The annual coal consumption shall be 1.83 Million Tons at 80% PLF.

Inside the plant boundary, railway siding shall be provided along with necessary Wagon Tippler arrangement for unloading of coal.

The daily requirement will result in to about one rake to two rake of coal comprising each rake having 58 wagons with coal carrying capacity 58 Tons per wagons (i.e. 3364Tons). Daily coal requirement at full load is 5016 Tons and 15 days requirement of uncrushed coal would be maintained in the plant.

5.3.3 Auxiliary/Secondary Fuel

Auxiliary/Secondary Fuel viz. LDO & HFO would be required for startup & flame stabilization at lower load. The required fuel oil has been estimated to be about 3725KL per annum and will be sourced from nearest refinery at Digboi through road tankers.

5.3.4 Power Evacuation:

One number, double circuit 400kV transmission lines proposed for the from power station switchyard up to Tinsukia EHV sub-station from the proposed generating power plant. The distance of this sub-station from power house site is around 60 Km. One

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400kV switchyard will be constructed in the proposed power plant for evacuation of power.

5.3.5 Environmental Considerations

The site of the proposed power plant is highly undulated with ridges and valleys covered with tea plantation & forest. Preliminary Geo-technical investigation for the proposed project area is being carried out. There is no sanctuary, national park or archeological monuments within 25 Km radius of the proposed site. River water will be used in semi- open circuit for circulating water system. The proposed power station would be equipped with modern, efficient pollution control devices to bring down the emission/discharge of pollutants within the acceptable norms of the country

A study to assess the environmental impact of the proposed project will be conducted and an Environmental Impact Assessment (EIA) report is to be prepared and furnished to relevant agencies as per normal practice.

ASSAM POWER GENERATION CORPORATION LIMITED 21 THIRD FLOOR,BIJULEE BHAWAN,PALTAN BAZAR,GUWAHARI-01,ASSAM

PRE FEASIBILITY REPORT FOR 1X 660 MW SUPER CRITICAL MAR GHERITA THERMAL PROJECT, DISTRICT-TINSUKIA, ASSAM

SECTION – 6

SELECTION OF SUPER CRITICAL TECHNOLOGY

6.1.0 Technology Selection

Higher capacity units came into operation in many countries at the end of last century unit capacities have increased to 1300 MW. However in India, except for a few units, the vast majority of the units were of 30 to 60 MW size till the seventies, India have quite a few 500 MW units in successful operation from eighties onwards. Still higher size unit like 660 MW units, are in the pipe line and are yet to be commissioned. Now entrepreneurs have proposed to manufacture large unit size of 800 MW to 1000MW as the next size in the country with Super Critical Technology to increase the pace of capacity addition.

The coal fired thermal power plants in India generally adopt sub critical technology for generation of power. The overall thermal efficiency of a conventional / sub-critical (operating steam pressure temp at 130 Kg/sq.cm,5400C) coal fired thermal power plants depends on the combustion technology, operating conditions and coal properties.

Sub Critical Boilers (500 MW sets) involves steam pressure of 170 bar and super heat / reheat temperature 540 0C/540 0C and super critical boilers would be designed with pressure of 257 ata and super heat/reheat temperature of 568 0C /592 0C. Main

focus about super critical boiler is on minimizing CO 2 emission originating from the fossil fired plants. CO2 increase is linked to Global warming. Hence it offers advantage of “Burn less fuel for the same output” thus economical use of energy resources and low emission.

Above an operating pressure of 225 Kg/sq.cm (temp.560 deg. C), the cycle is supercritical wherein the medium is a single phase fluid with homogeneous properties and there is no need to separate steam from water in a drum. Once through boilers are therefore been used in supercritical cycles. Adoption of once through boiler technology has advantage of operational flexibility to respond quickly to load changes and grid fluctuations, siding pressure operation and shorter start- up times.

The proposed project employs supercritical coal fired power generation unit having 660 MW gross capacity. Supercritical technology, which is first-of-its kind in India, enables Rankine cycle to be operated at higher operating pressures thereby increasing the cycle efficiency. Higher efficiency means a reduction in fuel consumption and thereby a reduction in emissions per unit of electricity generated. The supercritical technology will enhance operational efficiency over sub-critical technology, which is the most prevalent and commonly used for thermal power generation in India. ASSAM POWER GENERATION CORPORATION LIMITED 22 THIRD FLOOR,BIJULEE BHAWAN,PALTAN BAZAR,GUWAHARI-01,ASSAM

PRE FEASIBILITY REPORT FOR 1X 660 MW SUPER CRITICAL MAR GHERITA THERMAL PROJECT, DISTRICT-TINSUKIA, ASSAM

Hence adopting super critical technology for higher size of coal based units leads to enhanced plant efficiency, less fuel consumption and reduced green house emissions.

Adopting supercritical technology has the following advantages:

• Superior technology • Reduced green house emissions • Environmental friendly / CDM benefits • Operational flexibility to grid fluctuations • Shorter start-up times • Reduced coal consumption • Savings in coal cost • Reduced O&M cost • Improved ash management

ASSAM POWER GENERATION CORPORATION LIMITED 23 THIRD FLOOR,BIJULEE BHAWAN,PALTAN BAZAR,GUWAHARI-01,ASSAM

PRE FEASIBILITY REPORT FOR 1X 660 MW SUPER CRITICAL MAR GHERITA THERMAL PROJECT, DISTRICT-TINSUKIA, ASSAM

SECTION – 7

TE CHNICAL FEATURES OF THE MAIN PLANT EQUIPMENTS

7.1.0 Steam Generating Units

The steam generator will be sliding pressure supercritical, once-through type, utilizing a

The steam generating unit for 660 MW will be sized for 2225 TPH steam flow at, 256 ata steam pressure and 568 °C main steam temperature, 593 °C reheat temperature with at 100% MCR Super heater outlet with design consideration of 100 % indigenous coal as prime fuel. This will ensure adequate margin over the requirement of Turbine at 100% MCR to cater for auxiliary steam.

The steam generator would be capable of maintaining main steam and hot reheat steam temperatures of designed value between 60-100% MCR load or better. The steam generator would be capable of operation with ‘the HP heaters out of condition’ and deliver steam to meet the turbo-generator requirement at 100% MCR.

The steam generators are coal fired with Heavy Fuel Oil firing (HFO) provision upto 30% Boiler Maximum Continuous Rating (BMCR) for low load operation & flame stabilization and Light Diesel Oil (LDO) firing provision to a maximum of 10% BMCR as secondary fuel and start-up fuel respectively.

7.1.1 Salient Features of the Proposed Boiler

• Once through sliding pressure supercritical boiler

• Vertical wall evaporator with rifle tubing.

• Conventional Two-pass

• Radiant reheat

• Balanced draft

• Low load start-up system up to 30%BMCR load.

• Tilting Tangential burners

• Side mill layout, cold PA system

• Two (2) axial reaction FD fans

ASSAM POWER GENERATION CORPORATION LIMITED 24 THIRD FLOOR,BIJULEE BHAWAN,PALTAN BAZAR,GUWAHARI-01,ASSAM

PRE FEASIBILITY REPORT FOR 1X 660 MW SUPER CRITICAL MAR GHERITA THERMAL PROJECT, DISTRICT-TINSUKIA, ASSAM

• Two (2) axial reaction PA fans

• Two (2) axial reaction ID fans

• Two (2) regenerative Tri-sector air heaters

• Nine (9) vertical spindle bowl mills

• Nine (9) gravimetric feeders (Microprocessor Based)

• ESP with 25 mg/Nm 3 outlet dust emission (with one field out condition)

• Micro-processor based BMS, SADC and SB controls.

7.1.2 Furnace

The boiler is a two-pass design of gas-tight welded-wall design. The boiler is of dry bottom type with vertical tubes enclosing the furnace from the coutant bottom to evaporator outlet.

7.1.3 Economiser

Economisers help to improve boiler efficiency by extracting heat from flue gases discharged from the final reheater section of a radiant-reheat unit. Heat is transferred to the feed water, which enters at a temperature appreciably lower than that of saturated steam. Economizers are arranged for downward flow of gas and upward flow of water.

Designing the economiser for counter flow of gas and water results in maximum log mean-temperature difference for heat transfer. Upward flow of water helps avoid water hammer, which may occur under the some operating conditions. The proposed economizer is an in-line, bare tube arrangement.

7.1.4 Superheater and Reheater

The superheater and reheater design depends on the specific duty to be performed. For relatively low final outlet temperatures, superheaters solely of the convection-type are generally used. For higher final temperatures, surface requirements are larger and of necessity, superheater elements are located in high gas-temperature zones. Wide-spaced platen superheaters or reheaters of the radiant type are then used as a standard boiler designs.

7.1.5 Boiler Pressure Parts

The boiler has convection heat transfer areas located inside a box formed by welded membrane walls. In these, wall openings are provided for wind boxes, flue gas outlet, access, inspection doors, and soot blowers.

ASSAM POWER GENERATION CORPORATION LIMITED 25 THIRD FLOOR,BIJULEE BHAWAN,PALTAN BAZAR,GUWAHARI-01,ASSAM

PRE FEASIBILITY REPORT FOR 1X 660 MW SUPER CRITICAL MAR GHERITA THERMAL PROJECT, DISTRICT-TINSUKIA, ASSAM

The boiler and its auxiliary equipment are designed and arranged in such a manner that all parts can be inspected with minimal effort. All important parts are accessible by platforms.

7.1.6 Firing System

Tangentially fired steam generators inject the fuel and air streams from wind boxes in the furnace corners, tangent to an imaginary circle in the center of the furnace. A single rotating flame envelope (commonly referred to as a fireball) is created. The impingement of laterally adjacent streams promotes bulk mixing for complete combustion. Since fuel/air mixing and corner ignition stability occur by global vortex rather than local swirl mechanics, the phrase “the furnace is the burner” is uniquely applied to tangentially fired units.

Tangentially fired boilers have demonstrated low NOx production. The long diffusion flames emanating from each corner, plus the large amount of internal gas recirculation generated by the cyclonic fireball, moderate fuel and air mixing. This forms the basis of an inherently low NOx system. In contrast, wall-fired boilers utilize groups of individually self-stabilizing burners that do not use global furnace flow patterns to achieve uniform fuel and air mixing. As a result, wall- fired arrangements, even that employing separate over fire air, typically create local zones of high temperature and oxygen concentration that lead to high NOx formation.

7.1.7 Pulverisers

The pulverizing system is a highly efficient, reliable and flexible system for meeting a wide range of solid fuel preparation needs.

Bowl mill type pulverizer has been continually refined to meet the ever-changing service conditions. Low power consumption, low maintenance costs, wide capacity range and high availability. Nine (09) numbers of pulverizers are envisaged.

7.1.8 Boiler Feed Pumps and Drives

Four (4) nos. of Boiler feed pumps are envisaged for the unit. Two numbers (2 x 50%) capacity turbine driven feed pumps shall be provided for the unit for normal working along with 2 X 30% Motor Driven Feed Pumps as stand by and start up purpose are envisaged.

The MD-BFP shall be driven by constant speed squirrel cage induction motor with hydraulic coupling between motor and main pump and booster pump at other end of motor. TD-BFP shall be driven by variable speed turbine drive with suitable coupling between turbine and main pump and booster pump at other end of turbine with a gear box for each TD-BFP.

ASSAM POWER GENERATION CORPORATION LIMITED 26 THIRD FLOOR,BIJULEE BHAWAN,PALTAN BAZAR,GUWAHARI-01,ASSAM

PRE FEASIBILITY REPORT FOR 1X 660 MW SUPER CRITICAL MAR GHERITA THERMAL PROJECT, DISTRICT-TINSUKIA, ASSAM

Main pump shall be horizontal, centrifugal type, multistage, outer casing barrel type with end rotor removal. Booster pump shall be single stage, two bearing design and double suction impeller type.

7.1.9 Electrostatic Precipitator

Steam generating unit shall be installed with Six (6) Electrostatic Precipitators comprising ten (10) bus sections in the direction of gas flow and two (2) bus sections perpendicular to the gas flow.

The ESP would have a collection efficiency of around 99.89%. The outlet dust concentration from the chimney will be limited to 25 mg/Nm3 as per the latest regulation of Central Pollution Control Board. ESP will be provided with One Hundred and Twenty (120) ash hoppers having capacity suitable for storing ash collected in at least one (1) shift operation of the Boiler at 100% MCR.

7.1.10 Brief Technical Specification of Boiler and Auxiliaries

All the below values are typical applicable for the unit only.

Table 7.1

Sl. No Description Units Values

A Boiler

1. Type of Boiler - Pulverized Coal Fired

Main Steam

2. Superheater outlet steam flow T/hr 2225

3. Steam pressure at SH outlet ata 256

4. Steam temperature at SH outlet Deg.C 568

Reheat Steam

5. Reheat steam flow T/hr 1609.97

6. Steam pressure at RH Inlet ata 55.92

7. Steam pressure at RH outlet ata 50.33

8. Steam temperature at RH inlet Deg. C 337.8

ASSAM POWER GENERATION CORPORATION LIMITED 27 THIRD FLOOR,BIJULEE BHAWAN,PALTAN BAZAR,GUWAHARI-01,ASSAM

PRE FEASIBILITY REPORT FOR 1X 660 MW SUPER CRITICAL MAR GHERITA THERMAL PROJECT, DISTRICT-TINSUKIA, ASSAM

9. Steam temperature at RH Outlet Deg. C 593.0

10. Feed water te mperature at economizer Deg.C 290.0 inlet 11. Flue gas outlet temperature Deg.C 145

12. Excess air(at 100% MCR) % 20

13. Superheat temp control - By spray

14. RH temp control By burner tilt + Spray +excess air adjustment 15. Safety Valves - As per system requirement on SH, RH etc. 16. Soot blowers - As per manufacturers design

17. Regenerative Airpreheater - Motor driven

18. Ambient air temperature Deg.C 32

19. Maximum temperature entering close Deg.C as per design requirement spaced platens B Electrostatic Precipitator

1. Number of precipitators per boiler Nos. Six (06)

2. Number of gas paths per precipitator Nos. Two (02)

3. Number of electrical fields (Zones) in Nos. Ten (10) series in the direction of the gas flow

4. Total number of electrical fields per Nos. 120 boiler 5. Space between the centers of collecting 400 electrodes across the gas path m 6. Outlet dust concentration with one mg/Nm3 25 field out of service max) 7. Maximum flue gas velocity through m/s 1

8. MinimumES P treatment time of flue gas sec 20

9. Minimum aspect ratio m 1.5

10. Specific collecting area m2 180

C. Boiler Feed Pump

ASSAM POWER GENERATION CORPORATION LIMITED 28 THIRD FLOOR,BIJULEE BHAWAN,PALTAN BAZAR,GUWAHARI-01,ASSAM

PRE FEASIBILITY REPORT FOR 1X 660 MW SUPER CRITICAL MAR GHERITA THERMAL PROJECT, DISTRICT-TINSUKIA, ASSAM

1. Number of BFP sets per STG unit Nos. 2 x 50% Turbo driven & 2 x 30% Motor driven 2. Liquid Handled - Bo iler feed water

3. Rated capacity m3 / hr 1600

4. Feed water temperature at pump º C 187.5 inlet 5. Type of Coupling - variable speed Fluid Coupling

7.2.0 Steam Turbine Generator ( STG )

The steam turbine of 660 MW, will be a horizontally split, multi cylinder (one HP, Two IP, Two LP) 3000 rpm multistage, tandem compound, single reheat, condensing type unit uncontrolled extractions for regenerative feed water heating. The turbine will be designed for main steam parameters of 247 ata, 565 0C at emergency stop valves of H.P. turbine.

The LP turbine will exhaust against condenser pressure of about 0.10 ata (refer HMBD). The Turbo-generator set will be designed for a maximum throttle steam flow at Turbine Valve Wide Open (V.W.O.) condition of about 105% of Turbine MCR condition. The turbine will be rated for a minimum of 660 MW and shall be capable of both constant variable pressure operations as well as with HP heater out.

The turbine auxiliaries shall comprise of the following:

- Automatic turbine test gear

- Low vacuum unloading gear

- Turbine governing system

- Initial pressure regulator

- Control fluid system

- Turning gear and oil pumps (ac/dc motor driven)

- Turbine oil system with centrifuge & vapour extractor, for bearings, generator seals, jacking, turning gear etc.

- AC/DC motor-operated Jacking oil pumps

- Lube Oil purification system

- Oil Cooler

- Automatic Turbine Run-up System (ATRS) ASSAM POWER GENERATION CORPORATION LIMITED 29 THIRD FLOOR,BIJULEE BHAWAN,PALTAN BAZAR,GUWAHARI-01,ASSAM

PRE FEASIBILITY REPORT FOR 1X 660 MW SUPER CRITICAL MAR GHERITA THERMAL PROJECT, DISTRICT-TINSUKIA, ASSAM

- Stress Evaluator

A fully automatic gland sealing system is provided and the turbo-generator is equipped with the following:

a) Electro-hydraulic governing system backed up by Hydro-mechanical system ensuring stable operation under grid fluctuation

b) Hydraulic oil driven rotor turning gear

c) Self contained lubricating oil system for supplying oil to Turbine and Generator bearings to the governing and control system and also to Generator Seal Oil System.

7.2.1 Condensing Equipment

One (1) no. of double pass surface condenser, having different back pressures will be provided per LP Turbine with cooling water side of condensers in series with adequate hot well capacity capable of maintaining the required vacuum while condensing steam at the maximum rating of the turbine, will be provided for the unit. The condenser is of box type construction with divided water box design and is provided operation of one half of the condenser while the other half is under maintenance. The steam space will be rectangular cross-section. The condenser is provided with integral air cooling section from which air and non- condensable gases are drawn out with the help of air evacuation equipment.

7.2.2 Feed Cycle Equipment

Three (03) high pressure (HP) horizontal / vertical heaters and U-tube type are provided with both drain cooling and desuperheating zones in addition to the normal condensing zone. HP heaters are provided with individual bypasses to allow isolation and maintenance. ASME-TWDPS-I recommendations for preventing water damage to turbine shall be followed.

Four (04) low pressure (LP) horizontal / vertical feed water heaters are envisaged. The LP heaters are designed to mountain in the condenser neck. The drain cooler shall be installed outside the condenser neck. Extraction pipes routed through condenser neck shall be provided with stainless steel shroud to prevent erosion due to steam. LP heater 2, 3 and 4 can be individually isolated and by- passed.

The unit is provided with a variable pressure Spray- cum-Tray -cum-Reboiling type deaerating heater with a feed water storage tank of adequate capacity. Deaerator is designed to deaerate all the incoming condensate and drain flow to keep the oxygen content of the condensate below the permissible limit of 0.005 cc / litre.

7.2.3 Brief Technical Specification of Steam Turbine and Major Feed Cycle Equipments

ASSAM POWER GENERATION CORPORATION LIMITED 30 THIRD FLOOR,BIJULEE BHAWAN,PALTAN BAZAR,GUWAHARI-01,ASSAM

PRE FEASIBILITY REPORT FOR 1X 660 MW SUPER CRITICAL MAR GHERITA THERMAL PROJECT, DISTRICT-TINSUKIA, ASSAM

Table 7. 2

S. No Description Units Values

A Turbine

1. Type - Tandem Compound

2. Number of cylinders - Multi Cylinder

3. Type of governing - Digital electro hydraulic

4. Speed RPM 3000

5. Maximum continuous rating per unit KW 660000

6. Mail Steam at HP Turbine emergency stop valve a Pressure ata 247 b Temperature Deg.C 565

7. Hot reheat steam at IP Turbine terminal point a Pressure loss from HP Turbine outlet ata 5.57 terminal point to LP Turbine inlet terminal b Temperature Deg.C 593

8. Condenser Pressure ata 0.104

9. Final feed water temperature Deg.C 290

10 Turbine speed min -1 3000

11. SH steam flow required for with 0% T/hr 1915.21

12. Circulating water to condenser per unit (@ m3/hr 65000

13. Maximum temp. rise of circulating water Deg C 9

14. Turbine Heat Rate Kcal/Kwh 1850

B. Condenser Cooling water Pumps

Number of pumps required - 5 (4 W +1 S)

1. ASSAM POWER GENERATION CORPORATION LIMITED 31 THIRD FLOOR,BIJULEE BHAWAN,PALTAN BAZAR,GUWAHARI-01,ASSAM

PRE FEASIBILITY REPORT FOR 1X 660 MW SUPER CRITICAL MAR GHERITA THERMAL PROJECT, DISTRICT-TINSUKIA, ASSAM

Rated capacity m3/hr 17000

2. Water inlet temp Deg C 33 0C (max) for condenser design. 3. Number of stages - Two (02)

4. Location - Indoor

7.2.4 Generator

The Synchronous generators shall be totally enclosed, horizontal shaft driven directly by steam turbine at 3000rpm. The generator shall be cylindrical rotor, continuously rated for the turbine outputs and rated at a minimum of 660MW, 0.85 (lagging power factor, delivering power at 21kV 3 phase, 50 Hz star connected, in IP- 54 enclosure. The generator will be provided with brushless excitation. The generators will be capable of operating in isolation or in parallel with the power grid, with voltage variations of ±5% and frequency variations of 47.5 to 51.5 Hertz. No load short circuit ratio of the generator at rated KVA and voltage will be about 0.49. The generator will have Class-F insulation with temperature rise limited to class`B’ limits and shall be hydrogen cooled. The inlet temperature of cooling water to the hydrogen coolers will be 33 degree C for design purpose.

All six terminals of generator windings will be brought out and three shorted in the neutral formation terminal box and grounded through secondary resistance loaded distribution transformer to restrict earth fault current and to reduce transient over voltage.

The generator will have overload capacity as per IEC 60034-3 and 150 percent of rated current for 30 sec after attaining thermal equilibrium at rated load and voltage. The generator will withstand an over speed of 20% for 2 min.

The excitation system will be capable of supplying excitation current of the generator under all conditions of operation of load voltage and power factor. Rated current and voltage of the exciter will be at least 120% of normal excitation current and at least 110% of no load excitation voltage with minimum of 150% ceiling. Each generator will be provided with the following:

a) Automatic high speed digital, dual channel AVR, capable of maintaining steady- state terminal voltage within +0.5% of the preset value under all operating conditions and capable of smooth and continuous running over the operating band width.

b) Excitation control cubicle.

ASSAM POWER GENERATION CORPORATION LIMITED 32 THIRD FLOOR,BIJULEE BHAWAN,PALTAN BAZAR,GUWAHARI-01,ASSAM

PRE FEASIBILITY REPORT FOR 1X 660 MW SUPER CRITICAL MAR GHERITA THERMAL PROJECT, DISTRICT-TINSUKIA, ASSAM

c) Surge protection equipment.

d) Neutral grounding equipment.

e) Current and potential transformers.

f) Generator control metering and protection panel.

g) Hydrogen cooling system.

h) Jacking oil, bearing oil and seal oil systems covered under turbine.

Table 7.3

S. No Description Values / unit

1. Rated KW capacity at TMCR 660000 KW

2. Rated KVA capacity 776470.58 KVA

3. Rated terminal voltage 21 KV

4. Rated power factor 0.85 lagging

5. Rated stator current 21347.404 Amp

6. Rated speed 3,000 RPM

7. Rated frequency 50 Hz

8. Efficiency at rated power output @ 0.85 p.f 98.82% (approx.)

9. Short circuit ratio Rated hydrogen pressure 0.5 ± 15%

(gauge) 3.5 kg/cm2

ASSAM POWER GENERATION CORPORATION LIMITED 33 THIRD FLOOR,BIJULEE BHAWAN,PALTAN BAZAR,GUWAHARI-01,ASSAM

PRE FEASIBILITY REPORT FOR 1X 660 MW SUPER CRITICAL MAR GHERITA THERMAL PROJECT, DISTRICT-TINSUKIA, ASSAM

SECTION – 8

TECHNICAL FEATURES OF BALANCE OF PLANTS

8.1.0 Mechanical Systems

Balance of plant includes coal handling plant, Fuel oil unloading storage and handling, Mill rejects systems, ash handling plant, plant water systems, cooling towers, Raw water treatment plant, CW chlorination, RW chlorination system, CW pumps, Condensate polishing unit, Effluent treatment plant, Air conditioning & ventilation system, Fire protection system, Hydrogen generation plant, Compressed air system, Elevators, Miscellaneous cranes & Hoists, Workshop equipments, chemical laboratory etc shall be designed to meet the plant requirements.

8.1.1 Coal Handling System 8.1.1.1 Coal availability and Requirement

Indigenous coal will be considered as the main fuel for the Proposed 1 X 660 MW power Plant. The coal will be sourced from the nearby mines of North Eastern Coalfields Ltd (NECL) near Margherita. There are numbers of mines operating in this coal field. These mines have railway siding and coal from these mines are handled by railway wagon or dumpers. The Coal requirement for the project will be 209 TPH which has been arrived based on firing the 100% indigenous Coal having GCV of 5500 kcal/kg & the plant heat rate 2186 kcal/kwh. The annual coal consumption shall be 1.83 Million Tons at 80% PLF.

8.1.1.2 Coal Transportation

Inside the plant boundary, railway siding shall be provided along with necessary Wagon Tippler arrangement for unloading of coal Railway consultant.

8.1.1.3 Proposed System Description

ASSAM POWER GENERATION CORPORATION LIMITED 34 THIRD FLOOR,BIJULEE BHAWAN,PALTAN BAZAR,GUWAHARI-01,ASSAM

PRE FEASIBILITY REPORT FOR 1X 660 MW SUPER CRITICAL MAR GHERITA THERMAL PROJECT, DISTRICT-TINSUKIA, ASSAM

Crushing System

Unloaded coal is conveyed to crusher house by belt conveyors via pent house and transfer points. Suspended magnets are provided on conveyors at pent house for removal of tramp Iron pieces. Metal detectors are also provided to detect non-ferrous materials present in the coal before crushers.

One number crusher house will be envisages for the proposed power plant, having 4 nos. of crushers (2W + 2S), arrangement with primary and secondary crushers with reversible belt feeders, flap gates & screens etc.

Crushers crush the coal up to (–) 25 mm size through primary and secondary crushers and after crushing convey to outgoing conveyors in the coal path through flap gates and reversible belt feeders.

Coal Conveying from Crusher House to Boiler Bunkers

Coal from crusher house will be conveyed to boiler bunkers through a series of conveyors with necessary flap gates, fixed trippers, motorized Traveling trippers.

Inline Magnetic Separators, metal detectors, Electronic belt scales shall be provided at appropriate places, Automatic type Coal Sampling unit, Dust suppression, Dust extraction and Ventilation system will be considered.

8.1.2 Ash Handling System

The ash handling system is designed to meet the following parameters:

Table 8.1 Coal consumption at full load 209 TPH Ash content in coal (worst) for design 15% Total ash produced 32 TPH Bottom Ash (25% - Design Condition) 8 TPH Fly Ash (90% - Design Condition) 29 TPH

The system envisages the following:-

a) Intermittent semi-dry extraction of Bottom ash

b) Dry fly ash collection in silos of 16 hours aggregate storage capacity and passing through FGD.

8.1.2.1 Bottom Ash System

ASSAM POWER GENERATION CORPORATION LIMITED 35 THIRD FLOOR,BIJULEE BHAWAN,PALTAN BAZAR,GUWAHARI-01,ASSAM

PRE FEASIBILITY REPORT FOR 1X 660 MW SUPER CRITICAL MAR GHERITA THERMAL PROJECT, DISTRICT-TINSUKIA, ASSAM

The scheme proposes semi-dry extraction and disposal of economiser and bottom for the first three year of operation of the plant. Ash utilisation of 50% in 1st year, 70% in 2nd year and 90% in 3rd year has been considered. Bottom ash from the furnace would be collected in a water-impounded hopper provided with feed gates, feed hoppers and clinker grinders. The bottom ash clinkers will be ground in clinker grinders and will be transported by jet pumps to ash slurry sump (for bottom ash) from where bottom ash slurry will be pumped to ash dump outside the plant boundary. The design capacity of bottom ash conveying system considered should be adequate to clean bottom ash collected in a shift of eight (8) hours within two (2) hours. There will be continuous make-up water to be supplied to Bottom Ash Hopper. The over flow water from BA Hopper and seal trough will be clarified and will be reused in the Ash Water System. Bottom Ash Slurry will be pumped to permanent Ash Pond. 100% Ash Water recovery system would be provided to recover and reuse the Ash Pond Water. The H.P. & L.P water pumps to be located in a common ash water sump in ash water pump house which will receive make-up water from CT blow down, recycled ash water from ash pond and raw water system, if required. However BA extraction and disposal by HCSD shall be explored during detail engineering.

8.1.2.2 Fly ash System

Fly ash collected in Economiser, APH, ESP and Stack hoppers shall be extracted and conveyed to intermediate surge hopper automatically and sequentially by means of vacuum generated by mechanical exhauster and shall be transported to fly ash silos by means of pressure conveying system. Fly ash removal shall be collected in every 8 hours in a day.

All air pre-heater hoppers and ESP hoppers will be provided with fly ash vacuum conveying systems having capacity to evacuate fly ash generated in a shift of eight (8) hours within four (4) to four and half (4½) hours. The vacuum conveying system shall have four(4) streams operating in parallel, each stream having a conveying capacity of not less than 60 TPH. Below each hopper one Ash intake valve will be provided to discharge fly ash into the ash-conveying pipeline to be conveyed pneumatically. The ash- air mixture flows through the pipeline for collection of fly ash in dry state into an intermediate surge hopper. The fly ash and air mixture flows into a highly efficient bag filter system where almost entire fly ash is removed and discharged into the intermediate surge hopper located below through separation in filter bags in the filter- separator unit. Necessary transfer hopper with airlock valves will be provided below the filter separator unit to ensure continuous discharge of fly ash without affecting the operation of the upstream vacuum system. Intermediate surge hopper will have fluidizing pads distributed properly at the bottom to allow smooth flow of fly ash into the downstream pressure conveying system. Suitably sized vent filter will be provided at surge hopper roof along with pressure/vacuum relieving equipment.

ASSAM POWER GENERATION CORPORATION LIMITED 36 THIRD FLOOR,BIJULEE BHAWAN,PALTAN BAZAR,GUWAHARI-01,ASSAM

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Necessary vacuum for the system will be created by water ring type vacuum pumps. Air discharged from bag filter separator will be flown into air washing unit for scrubbing of finer ash particles. Clean air will then flow to the vacuum pump. Total eight (8) nos. vacuum pumps will be provided (4 nos. working per stream + 4 nos. as common standby). The standby vacuum pumps would have interconnection facility with each stream. 100 Tons capacity Intermediate Surge Hopper (ISH) shall be provided close to the ESP, which will be of MS construction. From intermediate surge hopper, the fly ash would be conveyed through pressurised pneumatic system using air compressor to the terminal silo located on the fringe of the plant boundary wall.

Dry fly ash from the intermediate surge hopper will be conveyed to the terminal fly ash silos by a positive pressure conveying system. Ash feeder vessels shall be installed beneath the intermediate surge hopper and fly ash shall be transported to the terminal fly ash silos through pipeline from the surge hopper via feeder vessels. The combined storage capacity of three terminal fly ash silos shall be to store fly ash generated in 36 hours. Three (3) nos. terminal fly ash silos shall be provided, each having 12-hours effective storage capacity. Screw compressors shall provide pressurized air required for conveying. For the proposed unit, three (3) conveying line shall be provided, each having capacity to transport fly ash at the rate of not less than 100 TPH. A standby FA transport line will also be provided. Arrangement shall be made such that each fly ash conveying line can dump fly ash to either of the terminal fly ash silos. 4x50% capacity (2W +2S) screw compressors will be provided.

In the system, each terminal fly ash silo shall have three (3) outlets as follows:-

► One outlet with telescopic spout arrangement with rotary feeder/ orifice feeder for unloading dry fly ash into closed trucks.

► One outlet with dust conditioner arrangement with rotary feeder/ orifice feeder for unloading dry fly ash in conditioned form into open trucks.

► One outlet for future use. Dry fly ash unloaded into fly ash tankers and open trucks is disposed for the purpose of subsequent use like mine fill, landfill, cement plant, etc. Each terminal fly ash silo shall be provided with suitably sized vent filter and pressure/vacuum relieving equipment.

The ash water recirculation system would be provided for the Base System to recycle ash water from the ash pond to the plant Ash Handling System after treatment. The system would have the capacity to recycle 100% ash water from the ash pond. The system would comprise 3x50% ash water recirculation pumps, a pump house, a clariflocculator, clariflocculator sludge disposal system, piping, valves etc. as required. The pump house and the clariflocculator would be located near the ash pond. Continuous supply of fluidizing air during ash evacuation has been envisaged

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in all the hoppers of the ESP, stack and intermediate surge hopper to facilitate smooth and effective ash flow. For this, fluidizing air blowers of adequate capacity and pressure will be provided. The terminal fly ash silos will have separate independent fluidizing air system. Fluidizing pads are distributed properly at the bottom of intermediate surge hopper and terminal fly ash silos to allow smooth flow of fly ash into downstream system. The fluidizing air system would be complete in all respects with necessary electric air heater, insulated piping, valves and instruments to ensure satisfactory system operation. The in-plant surge hopper will also receive fluidizing air from the ESP hopper-fluidizing blower. Compressed air system for operation of different equipment and control instruments of Ash Handling System would be complete in all respects with necessary compressors (screw type), air drying system, piping, valves and instruments. HCSD system conveying fly ash slurry to ash pond for disposing fly ash for the first three years of operation is proposed in the scheme before full utilization of fly ash is achieved. Ash utilization of 50% in 1st year, 70% in 2nd year and 90% in 3rd year has been considered for sizing HCSD ash pond. The system will include necessary feeding device, mixing tank with agitator for preparation of ash slurry and HCSD pump and all other necessary equipment, control valves, valves, instrumentation complete in all respect. The water requirement at the mixing tank for preparation of ash slurry will be arranged from CT blow down of the plant water system. The concentration of ash slurry (weight of ash/weight of slurry) needs to be finalized after testing of composition, particle size, chemical properties etc. of fly ash expected to be generated from the steam generator. Proper study of the slurry rheology and water analysis also needs to be done. HCSD pump selection criteria i.e. piston type or piston diaphragm type will also depend upon the slurry characteristics and pump duty envisaged. For the purpose of the present project report the above system has been considered for working out the project cost. The Ash Handling System control room will be located adjacent or in the ESP control room for ease of operation. 415 V MCC and control panel for ash handling plant will be located in the control room. Ash handling system operation can be done in automatic sequential manner and/or remote manual mode from the PLC based control panel.

8.1.2.3 Fly Ash Collection and Disposal

There will be Four (04) silos for the collection of fly ash, each of 2000 m3 Capacity (Density 0.6 m3/kg) for Sixteen (16) hours storage of fly ash generated.

Three (3) fluidizing blowers with two heaters (both operating) have been considered, out of which two shall be working for each silo and one common standby.

8.1.2.4 Unloading & disposal system below silos

a) Dry disposal system:

Two (2) nos. dry unloading facility shall be provided below each silo. To unload dry fly ash into a closed tanker, telescopic chute type arrangement will be provided.

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Adequately rated oil free rotary screw type conveying Air compressors shall be provided to supply compressed air required for conveying fly ash from buffer tanks to fly ash silos.

8.1.3.0 Installation of FGD System

Flue Gas Desulphurisation (FGD) system is necessary to capture the sulphur in the flue gas when the boiler is fired with high sulphur coal. High percentage of sulphur is observed in indigenous coal especially in Margherita coal. Due to this FGD system must be envisaged. However, MOE&F while according environment clearance also stipulate that space is to be kept in the layout for installing FGD system, if required, in future. Flue gas desulphurisation (FGD) system to be installed in order to meet the Requirements of pollution control board.

8.1.3.1 FGD AND ITS LIME PROCESSING AND HANDLING PLANT

FGD Technology

Global environmental problems are drawing large attention in these days. Among these SOx emission has become a major issue and consequently the importance of Flue Gas Desulphuhzation (FGD) technology, as a counter- measure for this problem is becoming greater. The wet limestone/gypsum FGD process has been incorporated to thermal power plants over the last 30 years or more. The Flue-gas desulphurization (FGD) or SO2 scrubbing processes typically uses calcium or sodium based alkaline reagent. The reagent is injected in the flue gas in a spray tower or directly into the duct. The SO2 is absorbed, neutralized and/or oxidized by the alkaline reagent into a solid compound, either calcium or sodium sulphate. The solid is removed from the waste gas stream using downstream equipment. Scrubbers are classified as "once through" or "regenerable" based on how the solids generated by the process are handled. Once through system either dispose of the spent sorbent as a waste or utilize it as by-product. Regenerable systems recycle the sorbent back into the system.

Both types of system, once through and regenerable, can be further categorized as wet, semi-dry or dry. Each of these processes is described in the following paragraphs.

a) Wet Systems

In a wet scrubber system, flue gas is ducted to a spray tower where aqueous slurry of sorbent is injected into the flue gas. To provide good contact between the waste gas and sorbent, the nozzles and injection locations are designed to optimize the size and density of slurry droplets formed by the system.

A portion of the water in the slurry is evaporated and the waste gas stream becomes saturated with water vapour. Sulphur dioxide dissolves into the slurry droplets where it reacts with the alkaline particulates. The slurry falls to the bottom of the absorber where it is collected. Treated flue gas passes through a mist eliminator before exiting

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the absorber which removes any entrained slurry droplets. The absorber effluent is sent to a reaction tank where the SO2 alkali reaction is completed forming a neutral salt. In a regenerable system, the spent slurry is recycled back to the absorber. Once through systems dewater the spent slurry for disposal or use as a by-product.

Typical sorbent is limestone or lime. This method is very popular in the world and has been proved through manufacture and operation.

The highest removal efficiency is achieved by Wet scrubbers and this method has efficiency up to 98%, depending on the raw gas SO2 content. The unit is installed behind the ESP.

b) Semi-dry Systems

Semi-dry systems or spray dryers inject an aqueous sorbent slurry similar to wet system, however the slurry has a higher sorbent concentration. As the hot flue gas mixes with the slurry solution, water from the slurry is evaporated. The water that remains on the solid sorbent enhances the reaction with SO2. The process forms a dry waste product which collected with a standard particulate (PM) collection device such as bag house or ESP. The waste can be disposed, sold as a by-product or recycled to the slurry.

c) Dry Systems

Dry sorbent injection system, pneumatically inject powdered sorbent directly into the furnace, the economizer or downstream duct work. The dry waste product is removed using particulate (PM) collection device such as bag house or ESP. The flue gas is generally cooled prior to entering the PM control device. Water can be injected upstream of the absorber to enhance SO2 removal.

Dry sorbent systems typically use calcium and sodium based alkaline reagents. A number of proprietary reagents are also available.

This method too is a proven one through manufacture and actual operation. It is simple and reduces both SOx and HCl in flue gas. In this method flue gas passes the tower, the heat released from the flue gas dries the limestone slurry, which is sprayed into small jets. During drying process SOx is absorbed. The lime stone mud after absorbing SOx is dried and has the same form as the ash. It is then collected in the dust precipitator. The absorption tower is thus installed before ESP. The removal efficiency is typically less than 80%, although in some of the recent units, higher efficiencies have been achieved.

Comparisons of the FGD technologies are given below:

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Table 8.2 Sl. Description Wet type Dry type No . 1. Power consumption Higher Lower 2. Material of absorber Lined alloy or CS Unlined CS 3. Process More complicated Less complicated less equipment more equipment 4. Reagent Less expensive More expensive 5. Reagent utilization High Low 6. Reagent storage Shed Silo 7. SO2 removal Up to 99 % Above 80% with bag house.

8. Module size Single module up to Upto 400 MW for higher size 1000 MW is multiple units required. operational. 9. Stack FRP line required Carbon steel liner 10. Absorber outlet duct Lined Carbon steel Carbon steel

11. By product Wet not easy to Dry easy to handle but has little handle can be sold in market value market. 12. By product de - Required Not required watering 13. Fuel type High sulphur fue l up Low sulphur fuel typically less than to 8% sulphur coal. 1.5% sulphur coal. 14. Slurry pH 5 to 6 11 to 12. 15. Preparation Wet grinding Grinding slaking 16. Used Water Requires treatment Treatment not required It may also be noted that the spray dryer FGD technology or the circulating dry scrubber technology are limited to a maximum absorber size of 400 MW, whereas the wet limestone FGD technology is not.

Wet FGD technology has lower life cycle cost for larger units burning high sulphur coal and requiring high SO2 removal, whereas dry FGD technology has lowest life cycle cost if required SO2 removal is achievable.

Choice of Technology

Basic conditions which are expected to be fulfilled by a FGD plant are:

1) Good Sulphur Removal efficiency (not less than 95%).

2) High plant reliability.

3) Easy operation and maintenance

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4) Not a source of secondary pollution.

5) Enables use of easily available absorbent with good marketability of the by- product.

6) Low in operation and construction costs.

For lower life cycle cost wet type FGD system is envisaged. The choice is between LSFO and MEL wet type technology.

LSFO systems have achieved SO 2 removal efficiencies as high as 98% in power plants firing a variety of high- and low-sulphur fuels.

MEL forced oxidation systems have achieved a better level of performance than the LSFO process, with SO2 removal efficiencies between 98% to 99% in power plants also firing a variety of high and low-sulphur coals.

In this project 90% efficiency of FGD is adequate to take care of the requirement in World Bank emission norms. The wet limestone / gypsum (LSFO) process which fulfills the above conditions in the treatment of large flue gas volume from thermal power stations has therefore become the main stream technology and is being widely adopted. Hence wet type LSFO FGD technology is envisaged for this project due to lower life cycle cost and capability of burning of high sulphur coal and high SO 2 removal with at least 95% efficiency of SO2 removal.

8.1.3.2 Flue Gas System

Flue Gas from the boiler is induced Into the FGD plant by ID fans. Total gas pressure loss in the FGD plant is compensated by ID fans. Bypass duct is provided to permit isolation of FGD plant or flexible operation of boiler and FGD plant.

A high sealing efficiency damper is provided at the bypass duct of each FGD plant. A damper is provided at the FGD Inlet duct. Similarly a damper is provided at the FGD outlet duct. Seal air fans are installed for every damper.

8.1.3.3 Limestone Handling Processing & Handling

Limestone for the station FGD would be received from the mines by road or rail. Around 600 Tons of limestone per day is envisaged for WFGD units. Availability of sized Limestone shall be explored, and the size available shall be finalised during detail engineering. Limestone would be stacked in the limestone storage yard as shown in the plot plan. The Limestone will be picked up by pay loader for feeding to the payer of steep angle conveyors. Steep angle conveyors will feed Limestone on to reversible shuttle conveyors. Reversible shuttle conveyors in turn will feed Limestone to the two number Limestone silos provided with its own bag filter. The bag filters are provided with a pulse jet cleaning system. When the level in the limestone slurry tank goes below a pre-determined level, Limestone will be evacuated from the Limestone silos with the ASSAM POWER GENERATION CORPORATION LIMITED 42 THIRD FLOOR,BIJULEE BHAWAN,PALTAN BAZAR,GUWAHARI-01,ASSAM

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help of gravimetric feeder/vibrating feeders which is preset to feed a fixed rate of limestone, and will be fed to the feeder conveyors. Feeder conveyors will discharge Limestone on a conveyor. This conveyor will receive Limestone from transfer tower/house to discharge Limestone on another Conveyor. Finally from the next transfer tower/house Limestone will be supplied to the Limestone Milling House through conveyor. A corresponding metered amount of water to make limestone slurry is introduced to the ball mill. Auxiliary equipment as indicated in Flow Diagram shall be provided as per normal engineering practice. Hydraulic press type belt pvulcaniser shall be provided for the Limestone handling plant. Dust extraction/suppression and Ventilation Systems, air-conditioning system for control room and other PLC, fire fighting system etc. shall be provided for the entire Limestone handling plant. Also service water and air, make-up water and drinking water facilities for LHP area are included under this package. The entire Limestone handling plant from unloading of limestone at limestone storage shed to Limestone Milling House shall be designed so that both the streams of conveyors and equipment can be run simultaneously as applicable and safely without any problem, in case of emergency operation of the plant. The design/rated capacity of each stream is considered to be 60 TPH respectively. All equipment of Limestone Handling Plant shall be suitable for 24 hours a day, round the clock operation.

8.1.4.0 Plant Water System

The Composite Water System shall be designed for economical utilization of water for the power plant. The water consumption for the plant is estimated to 3300 M3/hr for the power plant.

Table 8.3

Calculations are based on the Pre - Feasibility Report for Installation of SHREE SINGAJI THERMAL POWER PROJECT (Stage-II) – 2X660 MW prepared by M/S Ramky Enviro Engineers Ltd., Hyderabad.

Sl. Description Values in m 3/hr No.

i DM Water requirement

a Make -up water in power cycle @ 3% of 2225 m3/hr 67

b. DM Cooling water on Tank (Make up Tank) 2

Considering regeneration time of 4 hours the capacity ofDM 83 plant is worked out to 68.75 x 24/20

ii Filtered Water requirement

ASSAM POWER GENERATION CORPORATION LIMITED 43 THIRD FLOOR,BIJULEE BHAWAN,PALTAN BAZAR,GUWAHARI-01,ASSAM

PRE FEASIBILITY REPORT FOR 1X 660 MW SUPER CRITICAL MAR GHERITA THERMAL PROJECT, DISTRICT-TINSUKIA, ASSAM a. For DM Plant and Micro Filtration &RO requirement 83 b. For cooling tower water makeup (2.3% of Cooling tower 1587 capacity) c. For Potable Water 8 d. For Service water & Miscellaneous 125 e. Losses from UF &RO rejects 41 f. Losses from Clarifier rejects 57

Total Raw water requirement (from Sl. No. a to f. above) 1901 g. Design margin @ 10% of total water requirement 190

Grand total 2091

Say 2100

The make-up water shall be met from Buridhing River. The proposed raw water intake site is 14 Km away from project site. Necessary water intake systems are to be built and transported by means of pipe line to plant boundary raw water reservoir.

The raw water storage tank capacity of 0.273 Million m 3, which is used to store for 72 Hours with in the plant boundary. The raw water storage tank shall be bunded Type.

After passing through pre-treatment plant, the water will be tapped to meet the required make-up quantity from clarified water storage tank for semi-open circuit recirculation type of cooling system with induced Draft Cooling Tower for the unit has been proposed for the condenser cooling.

The Clarified & filtered raw water, further passes through the Multi grade filter, Ultra Filtration, Reverse Osmosis system and followed by Mixed Bed unit for Boiler make-up water requirements.

The clarified water will be used for Cooling Tower make up.

Service water, Potable water, Fire hydrant water and other Utilities water will be tapped from the Clarified Water storage tank, UF permeate tank, and raw water storage tank.

8.1.5.0 Raw Water Treatment System 8.1.5.1 Capacity of the water treatment plant

• Clarifier : 1 x 2500m3/hr

• MGF : 1 x 300 m3/hr (1W+1S)

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• UF : 1 x 300 m 3/hr (1W+1S)

• RO : 1 x 265 m 3/hr (1W+1S)

• Mixed Bed : 1 x 188 m 3/hr (1W+1S)

8.1.5.2 Poly Dosing System:

Polymer solution is dosed by means of an electronic diaphragm type-dosing pump for flocculation. Flocculation is the agglomeration of destabilized particles into micro floc and later into bulky floc which can be settled. The introduction of reagent called a flocculant or a flocculant aid may promote the formation of the floc.

8.1.5.3 Coagulant Dosing System:

Coagulation - flocculation processes facilitate the removal of suspended solids, turbidity and colloids. Suspended solids of sand and gravel of size greater than

1mm settle rapidly in water. Clay-like material of the size of a few microns take time to settle; while colloids which refer to particle size in the sub-micron range cannot settle naturally and so the process of coagulation - flocculation brings about the settling of these substances to effect their removal.

8.1.5.4 Chlorine Dosing System

Gas Chlorination serves the purpose of disinfection, in case bacteria are present in raw water. It is also useful for oxidation of ferrous ions to ferric state. The chemical is dosed by means of an electronic dosing pump wherein a facility is available for manual control of stroke length and stroke frequency.

8.1.5.5 Acid Dosing System

The Acid will be dosed in-line by electronic diaphragm pumps. It will have one pump. The hypo chlorite solution is stored in an adequate capacity HDPE tank equipped with a level indicator, level switch and other accessories.

8.1.5.6 Sodium Meta bisulphate Dosing System:

To prevent any residual chlorine from entering the Ro system and causing fouling of membrane a SMBS Dosing & ORP Analyser with auto dump valve is provided. In case the residual chlorine in water is high the auto dump valve will activate to prevent water from entering the system.

8.1.5.7 Anti-scalant Dosing System

To reduce the scaling tendency of calcium and magnesium over RO –membrane they are dosed With Anti-scalant to reduce the fouling the membranes .This willl improve the life and efficiency of the membrane .Acid and anti-scalant dosing will prevent the

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fouling of the membrane due to high concentration of the salts in reject by inhibiting the activity of Low solubility salts like calcium and silica.

8.1.5.8 Multi Grade Filter

The raw water is filtered through a Multi-Grade Filter (MGF) unit in order to remove suspended matters, turbidity, in the raw water. It is a MSEP vertical pressure vessel. Internally it is fitted with inlet distributor and a bottom collecting system. Externally, it is fitted with frontal pipe work and isolation valves.

This unit is charged with a uniform grade of filtering sand, which is supported on different grades of under bed materials. Suspended matters get entrapped when the raw water is passed in downward direction through the filter bed. The unit is isolated for backwash when the pressure drop across the sand bed increases more than specified limit of 0.8 Kg/Cm2.

8.1.5.9 Micron Cartridge Unit

This is a Vessel, houses the PP cartridge elements of 5 micron rating which remove micron size particles which otherwise will clog the R.O. Membranes.

8.1.5.10 High Pressure Pumps

Centrifugal vertical / multi-stage type of pump in stainless steel construction is provided for feeding the water to R.O. System at high pressure. Necessary instruments like High & Low pressure switch, pressure gauges & necessary valves are provided for this system.

8.1.5.11 Reverse Osmosis Module

This system removes dissolved solids by the principle of “Reverse Osmosis Process” at the rejection rate of 97 – 98%. This system consists of an epoxy painted structural steel skid for mounting of high pressure tubes with spiral wound membrane elements for each stream. Necessary control valves are provided with required instrumentation for operating & performing parameters.

Pressure gauges are provided for pressure indication and control of complete R.O. System. Online / bypass types of flow indicator at product & brine pipe work are provided for controlling desired flow rate & recovery. For monitoring product water quality online conductivity indicator shall be provided.

8.1.5.12 De-Gasification Tower:

The water from R.O. Unit is further passed-through a Degasser tower for removal of alkalinity present in raw water. It is a MSRL vertical pressure vessel, which is internally fitted with inlet distributor and a bottom collecting system. Externally, it is fitted with pipe work and isolation valves. This unit is filled with PP Pall Rings.

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8.1.5.13 DG Water Transfer Pump:

Two no Centrifugal type pump in SS construction is provided for feeding of water from the R.O. storage water tank to the MB units at the required flow rate and pressure of 3.5 Kg/Cm 2.

8.1.5.14 Mixed Bed Unit

The treated water is further passed through the Mixed Bed Unit for polishing of treated water from RO Plant and further reduces the conductivity of Boiler Feed Water. It is a MSRL vertical pressure vessel, which is internally fitted with inlet distributor and a bottom collecting system. Externally, it is fitted with frontal pipe work and isolation valves.

This unit is charged with cation & anion resins. For Re-generation of mixed bed unit, HCl & NaOH are used to re-charge the resin once stipulated time. The unit is isolated for regeneration when the conductivity leakage goes beyond specified limit.

8.1.5.15 pH Correction Dosing System:

The water from the outlet of M.B. System has pH in the range of 6.9 – 7.1. It is necessary to adjust pH & for this purpose we have offered pH correction dosing system. One (1) No. Chemical solution preparation tank and two no. of electronically operated diaphragm type dosing pump is provided for this purpose.

8.1.5.16 Chemical Cleaning System

This system is provided for the removal of any type of fouling occurring in R.O. System. It consists of a HDPE chemical preparation tank, a centrifugal pump in SS construction & a separate micron cartridge filter (5 micron rating) with interconnecting pipe work & isolation valves. Necessary instruments like pressure gauge, flow indicator and a level indicator is provided. Depending upon the chemical responsible for membrane fouling, the cleaning chemical solution is prepared. This system consists of the following equipment:

• Chemical Preparation Tank

This is a vertical, cylindrical storage tank of HDPE construction used for preparation of various cleaning chemicals depending upon the foul ant in the membranes. This is fitted with inlet /outlet, overflow/drain, pipe work with isolation valves. These units will have agitator drives through an adequately size motor.

• Chemical Cleaning Pump

A separate pump shall be provided for this purpose. Necessary suction and discharge pipe work with isolation valves are provided. This pump is used for recirculation of cleaning chemicals from tank to the R.O. System and back to tank.

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• Micron Cartridge Filter:

This micron cartridge filter housing is provided due to its requirement of compatibility with vigorous cleaning chemicals required to clean R.O. Membranes at varying pH from 2 – 12.

During R.O.Cleaning operation, cleaning chemical solution is first prepared in chemical tank as per specified instruction. This solution may contain suspended / un- dissolved impurities which need to be prevented from entering in R.O. System. This micron cartridge element is of 5 micron rating and prevents the impurities.

8.1.5.17 Chlorination Plant

Chlorine dosing is considered to control bio-matter in cooling water & raw water.

8.1.5.18 Chlorination for Clarified Cooling Water

Shock dosing of chlorine of minimum 5 ppm shall be provided to prevent bio- growth in condenser cooling water. To achieve that (100%) capacity, chlorination plant taking chlorine from chlorine tonners to be provided. Plant shall be complete with absorption system. Empty tonners for 30 days chlorine storage and interconnecting piping shall be provided.

There should be two steams in CW chlorination system; each will consist of the following:

One number ejector, chlorinator, motive water booster pump, diffuser etc, Clarified water (Motive water) shall be taken to the inlet of chlorination system (booster pump suction).

• Required numbers ton containers for chlorination plant are envisaged for storing chlorine in liquid vapour phase. All shall be housed in Chlorine Tonner room.

• Mono rail Hoist of required capacity with lifting/handling arrangement for Tonners.

• 2x100% booster pumps. Clarified water (Motive water) for which shall be taken from a suitable source.

• One number portable residual chlorine analyzer.

Chlorine leak Absorption system shall be provided which shall be capable of handling leakage of 1 (one) ton chlorine.

8.1.5.19 Chlorination for Raw Water

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Two (2) numbers streams (1w+1s) each of capacity 25 kg/hr tonner mounted gas chlorination plant shall be provided for chlorination of raw water feeding to water treatment plant. Required numbers empty chlorine tonners to be provided for 30 days requirement.

Complete plant shall be manually operated. However, necessary interlocks and instrumentation required for the safe operation and supervision of plant will be provided as required.

8.1.5.20 Potable Water Chlorination

Two (2) numbers chlorinators (1w+1s) capacity each 0.1 kg/hr shall be provided for Potable water required for proposed plant. For potable water minimum 2 nos. empty cylinders shall be provided.

I. Chemical Dosing System

To maintain the quality and pH of feed water, chemicals are dosed in the LP and HP side of the feed water cycle.

1) LP Dosing System

The LP dosing consists of two dosing system i.e., Hydrazine dosing, Ammonia dosing and oxygen dosing each on independent skids one for each unit and one number NaOH dosing skids per unit for ECW system are included.. The details of each dosing system are given below:

a) Hydrazine Dosing System

In order to control the effect of residual oxygen present in condensate, continuous dosing dilute solution of hydrazine is done. For this purpose a skid mounted hydrazine dosing system shall be provided.

Skid shall mainly comprise of following equipments:

i) One (1) number solution preparation cum metering tank with accessories for 24 hours storage capacity.

ii) Two (2) numbers dosing pumps (2x100%).

iii) All necessary instruments, piping, valves & fittings etc.

b) Ammonia Dosing System

Boiler feed water/condensate water should have proper pH in order to protect the system from corrosion. In order to control the same dosing of dilute solution of Ammonia is done at CEP discharge header. For this purpose a skid mounted ammonia dosing system for each unit to be provided.

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One (1) no. skid shall be provided for the unit.

Skid shall mainly comprise of the following equipment:

i) One (1) number solution preparation cum metering tank with accessories for 24 hours storage capacity.

ii) Two (2) numbers dosing pumps (2x100%).

iii) All necessary instruments, piping, valves & fitting etc.

c) Oxygen Dosing System

Constant feed of highest purity Oxygen will fulfill the dosing requirements. An hourly consumption of approximately 120 g/h is envisaged during normal operation. The feed water checked at the economizer inlet shall have an oxygen content of approx. 50 µg/L at full load during continuous operation. During start-up & shut – down operations, the oxygen dosing system is switched off.

d) NaOH Dosing System for ECW System

Sodium Hydroxide (NaOH) dosing system is provided to dose NaOH solution in Equipment cooling water lines to increase pH upto 9.5. The sodium hydroxide dosing is done in the DMCW overhead tank during the initial fill and for the compensation of cooling water for any leakage during normal run. The 1% solution of NaOH is prepared manually by opening the inlet valve of DM water and adding NAOH lye in basket.

The dosing system consists of followings:-

• One (1) no. Solution Preparation cum storage tank with CO 2 absorber and other accessories shall be provided.

2) Anti-Scalant & Bio-Cide Dosing

The antiscalant is dosed in CW forebay/sump to control scaling & corrosion in the system. Biocide is to control bio growth in the cooling water cycle.

i) Skid Mounted Anti-Scalant/Corrosion Inhibitor shall consists of following equipments

a) Two (2) numbers solution preparation cum metering tanks with accessories for 24 hours storage capacity.

b) Three (3) numbers dosing pumps (3x100%).

c) All necessary instruments, piping, valves & fittings etc.

ii) Skid Mounted Bio-Cide dosing shall consists of following equipments

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a) One (1) number solution preparation cum metering tank with accessories for 24 hours storage capacity.

b) Two (2) numbers dosing pumps (2x100%).

c) All necessary instruments, piping, valves & fitting etc

8.1.6.0 Cooling Towers (CT)

One (01) nos. of the induced draft type cooling tower shall be provided the power plant. The cooling tower will discharge the re-cooled circulating water to CW pump house circulating water sumps.

Number of cooling towers : One

Type of cooling tower : Induced Draft.

Design inlet circulating water flow rate : 69,000 m3/hr

Cooling range of circulating water : 10 0C

Ambient wet-bulb temperature : 26.4 0C

Circulating water makeup : Clarified water

Suitable arrangement for shock & continuous dozing of chlorine to curb organic growth and chemical dozing i.e. scale / corrosion inhibitor and biocide dozing for maintaining 5.0 COC are made.

8.1.7.0 Station Effluent Treatment System

• Oily water waste from transformer area, in the event of Fire spray, shall collect in a local pit in each unit. Oily water from transformer oil separator shall be transferred by 2X100% screw pumps to an oily waste collection sump.

• Waste water from TG hall shall be collected in local pits. Oily water from TG hall shall be transferred 2X100% screw pumps to a oily waste collection sump.

• Waste water from fuel oil area shall be transferred 2X100% screw pumps to a oily waste collection sump.

• Above collected oily wastes in common collection sump shall be treated in a TPI separator. The clean water after treatment is transferred to central monitoring basin. The recovered oil is stored in barrel/tank for further disposal manually. Sludge from TPI separators shall be collected in trolley for further disposal manually.

ASSAM POWER GENERATION CORPORATION LIMITED 51 THIRD FLOOR,BIJULEE BHAWAN,PALTAN BAZAR,GUWAHARI-01,ASSAM

PRE FEASIBILITY REPORT FOR 1X 660 MW SUPER CRITICAL MAR GHERITA THERMAL PROJECT, DISTRICT-TINSUKIA, ASSAM

• The wash water wastes from boiler area shall be collected in a sump and shall be transferred by 2X100% centrifugal vertical pumps to waste water collection sump.

• The side stream filter back wash shall be transferred by 2X100% centrifugal vertical pumps to waste water collection sump.

• The Pre Treatment Plant filter back wash shall be transferred by 2X100%

Centrifugal vertical pumps to waste water collection sump.

• Above collected waste in waste water collection sump shall be treated in Lamella clarifiers or tube settlers to remove the suspended solids. The clean water after treatment shall be transferred to central monitoring basin. The sludge generated shall be further treated in 1X100% thickener.

• A dedicated chemical dosing system with tanks and 2X100% metering pumps common for lamella clarifier and thickener shall be provided.

• The sludge generated from the lamella clarifier and RO plant clarifier shall be collected in the sludge sump and shall be transferred to 2X5 m 3/hr. centrifuges. The clear water generated shall be transferred to CMB and the cakes shall be manually removed.

• Power cycle blow down of each unit shall be collected in a boiler blow down sump of respective unit and will be transferred to central monitoring basin by

2X100% vertical centrifugal pumps.

• Regeneration waste from neutralization pit in DM Plant area and CPU plant shall be pumped by 2X100% pumps to central monitoring basin.

• Auxiliary steam condensate from the fuel tank heating line shall be collected in the fuel oil area oil collection pit.

• The water from central monitoring basin can be used as a make up to ash handling plant or horticulture with an emergency dump to ash pond.

• It may be noted that, various wastewater generated above are treated either in TPI separator/Lamella clarifier/tube settler or transferred without any further treatment to central monitoring basin/other systems. The above system facility shall remove only oil and suspended solids up to the following limits:

• Suspended solids : 100 ppm max.

• Oil and grease : 20 ppm max.

ASSAM POWER GENERATION CORPORATION LIMITED 52 THIRD FLOOR,BIJULEE BHAWAN,PALTAN BAZAR,GUWAHARI-01,ASSAM

PRE FEASIBILITY REPORT FOR 1X 660 MW SUPER CRITICAL MAR GHERITA THERMAL PROJECT, DISTRICT-TINSUKIA, ASSAM

• PH : 6.5 to 8.5

• Plant domestic waste & sanitary water will be collected by gravity to septic tanks for anaerobic treatment. Sewage is then allowed to pass through as up- flow filter. During the process, most of COD, BOD and TSS are removed. Overflow from up flow filters after disinfection using chlorination will be distributed for horticultural purpose only.

8.1.8.0 Compressed Air Scheme

The compressed air system is comprised of the instrument air system and the service air system. Instrument air is required for the various pneumatically operated valves and instruments in the power plant, while service air is required for general plant services.

Two (2) Nos. identical air compressors (1W+1S) common for instrument air and service air system is provided. 1 X 100% compressors (common for IA & SA) for the unit and one (1) standby is provided.

The Capacity of each compressor is 90 NM 3/Min at 8.0 Kg/cm 2 (g).

Two (2) nos (1W + 1S) Air Drying Plant at a working pressure of 8.0 Kg/Cm 2 (g) shall also be provided to supply moisture free air to instruments. Air-drying plant capacity shall be adequate for the IA requirement. Air Drying Plant shall be heat of Compression “HOC” type. Dew point of air at the outlet of ADP shall be –20 oC at atmospheric pressure.

Six (6) nos Air receivers, i.e., 2 nos. for IA system & 2 nos. for SA system near compressor house and 2 nos. unit air (IA) receivers in TG building of 10 M 3 capacity each shall be provided, designed and constructed in accordance with the requirement of the ASME unfired pressure vessel code

8.1.9.0 Condensate Polishing Unit (CPU)

The Condensate Polishing Plant (CPP) shall treat the condensate of the respective Turbine-Generator (TG) Units of the power station.

The Condensate polishing Plant shall consists of one set of Condensate polishing Unit (CPU) for the TG unit inside TG Building. Each CPU shall consist of Four (4) service vessels (Three working & one standby vessel) of 33.33% capacity for the TG Unit.

The regeneration system shall be external and common to the CPU of the TG unit. For regeneration, resin from the exhausted exchanger vessel will be transferred hydraulically to this facility. The exhausted resin charge will be cleaned, separated, regenerated, mixed and rinsed before being stored for the next use.

The common influent and effluent headers of each CPU will be connected to an automatic bypass line (s). On high pressure signal across the service vessel, the

ASSAM POWER GENERATION CORPORATION LIMITED 53 THIRD FLOOR,BIJULEE BHAWAN,PALTAN BAZAR,GUWAHARI-01,ASSAM

PRE FEASIBILITY REPORT FOR 1X 660 MW SUPER CRITICAL MAR GHERITA THERMAL PROJECT, DISTRICT-TINSUKIA, ASSAM

automatic control valve(s) in the bypass line(s) shall open, bypassing the service vessel(s). Make-up water to the turbine cycle will be added to the condenser hot well as required.

The influent quality during start up may deteriorate to:

Table 8.4 DS Ppb 2000 max silica Ppb 150 max Crud Ppb 1000 max (Mostly black iron oxide)

8.1.10.0 Ventilation & Air-conditioning System

A Central Chilled Water type Air Conditioning Plant with one Vapour Absorption Machine (VAM) of 100% duty (working) and one screw chilling unit of 100% duty (standby) shall be provided to cater to the air conditioning requirements of the following areas.

• Common control room, control equipment rooms, computer room, Relay Panel & UPS room, SWAS rooms, Analyzer room, C&I maintenance Engineer’s Room, Record room, AVR, common for both Units of power house building.

• ESP-VFD Control Room

A Central Chilled water type air conditioning plant is provided for air conditioning of the following areas of Service Building.

• Offices & Meeting Areas

• Instrumentation Lab and office

• Chemical Lab & Office

• Electrical Lab

• Conference Room

• Split type Air Conditioners

Split type air conditioners (air cooled) are provided to cater to the air conditioning requirements of the following areas of Service Building.

• DM Plant Control Room

• Control Room of Water Treatment Building

• Control Room of Coal Handling Building

ASSAM POWER GENERATION CORPORATION LIMITED 54 THIRD FLOOR,BIJULEE BHAWAN,PALTAN BAZAR,GUWAHARI-01,ASSAM

PRE FEASIBILITY REPORT FOR 1X 660 MW SUPER CRITICAL MAR GHERITA THERMAL PROJECT, DISTRICT-TINSUKIA, ASSAM

• Control Room of Ash Handling Building

• Stores in-charge room of Ware House

• Computer punching Room of Security & Time Building

Ventilation of the miscellaneous areas and other buildings will be provided as required for equipment operation and personnel comfort. Toilet and battery areas will be provided with exhaust fans.

8.1.11.0 Cranes and Hoisting Equipment

One number of 130/30T Capacity EOT crane is envisaged in the T.G. Hall. The crane will be double box girder, M3 duty, and indoor duty.

8.1.12.0 Fuel Oil System

The Fuel Oil System shall consist of light diesel oil system and heavy fuel oil system to the steam generator igniters. Light Diesel Oil (LDO) shall be used for initial start up while heavy Fuel Oil Fuel Oil (LSHS/HPS/HFO Gr HV) shall be used for flame stabilization and during low load operation.

Normal annual requirement would be based on statistical average of oil consumption of 3.2 ml of HFO per Kwh of power generation. 15 days of oil storage is envisaged adequate during trial operation. Total HFO & LDO storage capacity shall be designed based on these parameters

8.1.13.0 Hydrogen Generation Plant

The Hydrogen Generation Plant shall be of Bi Polar design only having 2 streams (2 x 50 %) of 10 Nm 3/hr capacity of H2 Gas Generation is envisaged. The approx. Hydrogen gas requirement will be about 150 Nm 3/day.

8.1.14.0 Fire Protection System

For protection against fire, all yard equipment and plant equipment will be protected by a combination of hydrant system; automatic sprinkler spray system (emulsifier system); fixed foam system for oil handling areas; automatic high velocity and medium velocity sprinkler spray system; auto-modular inert gas based system for control rooms apart from portable and mobile fire extinguishers located at strategic areas of plant buildings and adequate Passive Fire Protection measures. The systems will be designed as per the recommendations of NFPA or approved equals in accordance with the Tariff Advisory Committee of the Insurance Association of India stipulations.

8.2.0 Electrical System 8.2.1 Basic Design Concept

ASSAM POWER GENERATION CORPORATION LIMITED 55 THIRD FLOOR,BIJULEE BHAWAN,PALTAN BAZAR,GUWAHARI-01,ASSAM

PRE FEASIBILITY REPORT FOR 1X 660 MW SUPER CRITICAL MAR GHERITA THERMAL PROJECT, DISTRICT-TINSUKIA, ASSAM

For designing the various electrical systems and equipment the following basic concepts will be applicable:

• Ambient temperature: The design ambient air temperature will be 500C.

• Voltage levels: Voltage levels in the proposed plant will be 400 KV and 220KV for Interconnection with grid, 21 KV for 660MW generation. Large Motor (1500KW and above) like BFP, CWP, ID, PA and supply feeders to Transformer shall be connected in 11KV Swgr. Motor above 200KW upto 1500KW shall be connected to 3.3KV Swgr. Auxiliary motors of 200KW and below shall be fed in LT. Single phase AC motors will not be used except in very special cases of low power for which panel mounted 415/240 volt transformers will be used. For 110 volt AC control supply, if used, separate panel mounted 415/110 volts transformers will also be used.

• Variations: Voltage variation will be ±10%, frequency variation shall be ±5% and combined voltage and frequency variation will be ±10%.

• Fault levels: Fault levels for the various voltage systems shall be as under

400 KV 40KA for 1 Sec.

220 KV 40KA for 1 Sec.

11 KV 40KA for 3 Sec.

3.3 KV 40KA for 3 Sec.

415 volt 50KA for 1 Sec.

220 volts D.C 25KA for 1 Sec

• Basic Impulse level: The basic impulse levels will be 1425 KVp for 400 KV, 1050 KVp for 220 KV, 75 KVp for 11KV System and 45 KVp for 3.3KV system.

• Control and Protection: Controls will be micro-processor based and centralized in a central control room.

8.2.2 Power Evacuation 8.2.2.1 Transmission Interconnection

One number of double circuit 400kV transmission lines proposed for the interconnection from power station switchyard up to Mariani Grid sub-station at 400 KV for evacuation of about 660 MW power from the proposed generating power plant. One 400 kV switchyard will be constructed in the proposed power plant for evacuation of power.

8.2.2.2 400KV Switchyard

ASSAM POWER GENERATION CORPORATION LIMITED 56 THIRD FLOOR,BIJULEE BHAWAN,PALTAN BAZAR,GUWAHARI-01,ASSAM

PRE FEASIBILITY REPORT FOR 1X 660 MW SUPER CRITICAL MAR GHERITA THERMAL PROJECT, DISTRICT-TINSUKIA, ASSAM

A 400kV outdoor Switchyard has been envisaged for evacuation of generated power through generator transformer from the proposed power plant. This switchyard will be located in an area separate from the main power house building and will be surrounded by a fence. The 400 kV outdoor switchyard will be designed with one and half breaker Scheme. The switchyard will be provided with the following fully equipped bays:

• 1- Generator transformer bay

• 2- 400 kV outgoing feeder bays

• 1- Station transformer bay

• One Number Spare Feeder Bay (with all equipment)

The switchyard will be of outdoor air insulated type. The switchyards will be provided with necessary circuit breakers, disconnectors, earthing switches, current transformers, surge arrestors, lightning arrestors, protective relays etc. Sequential Event Recorder (SER) of the switchyard signals will be provided. The switchyard bus bars shall have high speed three phase busbar differential protections with independent check feature and also over voltage protection. Moreover each bay shall be provided with local breaker back-up protection. These signals as a minimum will contain all perspective relays lock out relay and breaker auxiliary contacts. These will be hardwired to SER cabinet.

8.2.2.3 Switchyard Control Room

The control, monitoring and operation of the 400kV switchyard will be through SCADA in the Switchyard Control Room. The switchyard will have its own Control Building for accommodating SCADA system equipment and transmission Line Protection panels and other Switchyard auxiliary equipment. However SCADA shall be interconnected to power plant main DCS through serial link (Fibre optic cables) for monitoring purpose. Separate room will be provided to accommodate batteries for 220V DC System for control and supervision of the switchyard equipment and 48V DC System for PLCC system. Separate room will be provided for Tariff Metering Panels.

8.2.3 Power Transformers 8.2.3.1 Generator Step-Up Transformer

The Generator transformer for 660MW unit is of Three No. of single phase,

50HZ, 420/√3 / 21/√3 KV, YNd1, each 275/220/165 MVA, OFAF/ONAF/ONAN cooled oil immersed outdoor transformer. Generator transformer will be provided with On Load Tap Changer (OLTC) having tap change range of -12.5% to +7.5% in steps of 1.25%. Transformers will be provided with requisite protection devices and accessories. ASSAM POWER GENERATION CORPORATION LIMITED 57 THIRD FLOOR,BIJULEE BHAWAN,PALTAN BAZAR,GUWAHARI-01,ASSAM

PRE FEASIBILITY REPORT FOR 1X 660 MW SUPER CRITICAL MAR GHERITA THERMAL PROJECT, DISTRICT-TINSUKIA, ASSAM

One number spare single phase transformer will be provided for the unit, which is normally kept in energized condition.

The isolated phase bus ducts (IPB) will provide interconnection between the generator and generator circuit breaker and between generator circuit breaker and generator transformer with tap off to unit transformers

8.2.3.2 Unit Transformer (UT)

The Unit auxiliary transformer for 660MW unit is Two numbers, each Three phase, Two Winding, 21/11.6 KV 50HZ, Dyn11, 31.5 MVA, ONAF, 25 MVA ONAN, cooled oil immersed outdoor transformer. Unit transformer will be provided with Off Circuit Tap Changer (OCTC) having tap change range of ±5% in steps of 2.5%. Transformers will be provided with requisite protection devices and accessories. LV winding neutral is grounded through resistor of suitable rating limiting the phase to ground current to 300A.

8.2.3.3 Start-up Power Arrangement /Station Transformer

One number station transformers, each of three phase, three winding, 90/45/45 MVA ONAF, 72/ 36/36 ONAN cooled, YNyn0, yn0, shall be provided for Start-up power for the Unit and also caters to station common auxiliary loads.

8.2.4 Service Transformer 8.2.4.1 Unit Auxiliary Transformer (UAT)

Required Nos. of 11kV / 3.3KV adequately rated transformers for supplying the unit loads and station low voltage loads will be provided. The transformers are sized on the basis of 2 x 100% rating. These transformers will be provided with off circuit tap changer + 5% in steps of 2.5%. The auxiliary transformers will be DYn11 connected and the neutral will be effectively grounded.

These transformers shall be of mineral oil filled type suitable for outdoor location.

8.2.4.2 LT Auxiliary Transformer

Required Nos. of 11kV / 433V adequately rated transformers for supplying the unit loads and station low voltage loads will be provided. The transformers are sized on the basis of 2 x 100% rating. These transformers will be provided with off circuit tap changer + 5% in steps of 2.5%. The auxiliary transformers will be DYn11 connected and the neutral will be effectively grounded. These transformers shall be either mineral oil filled type suitable for outdoor location, or dry type suitable for indoor location.

8.2.5 Switchgears 8.2.5.1 11 KV Switchgear

ASSAM POWER GENERATION CORPORATION LIMITED 58 THIRD FLOOR,BIJULEE BHAWAN,PALTAN BAZAR,GUWAHARI-01,ASSAM

PRE FEASIBILITY REPORT FOR 1X 660 MW SUPER CRITICAL MAR GHERITA THERMAL PROJECT, DISTRICT-TINSUKIA, ASSAM

11KV switchgear will be metal-clad vertical single front draw-out type for indoor installation.

Degree of protection shall be IP4X. Breakers will be either SF6 or vacuum type, suitable for a rupturing capacity of 40 KA, closing and opening time not exceeding 5 and 4 cycles respectively. The breakers will be trip-free with anti-pumping device and operating mechanism of stored energy type with DC motor operated charging of spring. Busbar will be SPBD type. Bus bar will be Heat shrinkable PVC sheathed shroud-jointed and temperature of the bus bar at 500C ambient will be limited to 900C.

8.2.5.2 3.3 KV Switchgear

3.3 KV switchgear will be metal-clad vertical single front draw-out type for indoor installation.

Bus bar will be SPBD type. Bus bar will be Heat shrinkable PVC sheathed shroud-jointed and temperature of the bus bar at 50°C ambient will be limited to 90°C.

8.2.5.3 415 Volt Switchgear

415 volt switchgear will be metal clad vertical single/double front draw out type IP54 enclosure class for indoor installation. Panels will be arranged for bottom entry of cables, as required.

The incomers, ties and motors of 110 KW and above will be controlled by circuit breakers. Other feeders will be controlled by switch fuse/contactor for motors and switch fuse for feeders. Circuit breakers will be of air-break type. The rupturing capacity will be 50 KA.

Bus bar shall be PVC sleeved jointed shrouded and rated for 2500 Amps, or as required, with total temperature limited to 90oC at 50oC ambient.

8.2.6 Electric Drives

Electrical drives will be 3 phase 50 cycle squirrel cage energy efficient type induction motors operating at nominal voltages of 11000V, 3300V and415V Motors will be of high power factor (at least 0.85 for large motors), F class insulation, IP55 enclosure class (with canopy for vertical outdoor motors), designed for direct-on-line starting with as low starting current as possible.

Starting current for boiler feed pumps, and CW pumps shall not exceed 6.0 times (With no positive tolerance) the full load current.

ASSAM POWER GENERATION CORPORATION LIMITED 59 THIRD FLOOR,BIJULEE BHAWAN,PALTAN BAZAR,GUWAHARI-01,ASSAM

PRE FEASIBILITY REPORT FOR 1X 660 MW SUPER CRITICAL MAR GHERITA THERMAL PROJECT, DISTRICT-TINSUKIA, ASSAM

Motor rating will be at least 1.15 times the consumption at the duty point of the driven equipment.

Motors will be capable of starting and accelerating to full speed at 80% of the nominal voltage For BFP pump the motor shall be capable of starting at 70% of Nominal voltage. And will be capable of either two starts in quick succession with third start after 5 minutes. In cold condition or two start at 15 minutes intervals in hot condition, both cases with voltage and frequency variation limits. Motors will also be capable of restarting under full load after a momentary loss of voltage with the possibility of application of a total of 150% nominal voltage.

Motor torque characteristic will be such as to ensure smooth and rapid starting and acceleration of the driven equipment. Motors will be provided with suitable heating arrangement while at standstill.

8.2.7 Protection

Electrical protection proposed for the various equipment shall be generally as indicated below:

8.2.7.1 Generator and Generator Transformer

Generator:

• Differential (87G)

• Inter-turn fault (95)

• Stator earth fault (64G)

• Loss of excitation (40)

• Negative sequence current (46)

• Reverse power (32)

• Low forward power (37)

• Rotor earth fault (64R)

• Over-voltage (59)

• Under-voltage (27)

• Generator pole Slipping (98)

• Under frequency (81U)

• Over Frequency (81O)

ASSAM POWER GENERATION CORPORATION LIMITED 60 THIRD FLOOR,BIJULEE BHAWAN,PALTAN BAZAR,GUWAHARI-01,ASSAM

PRE FEASIBILITY REPORT FOR 1X 660 MW SUPER CRITICAL MAR GHERITA THERMAL PROJECT, DISTRICT-TINSUKIA, ASSAM

• Voltage balance (60)

• Overload (50)

• Backup impedance (21G)

• Inverse time over current (51)

• Thermal Over load(49)

• Over fluxing (99)

• Dead Machine Protection (50GDM)

• Rate of Change of Frequency (df/dt) - Stage-1

• Rate of Change of Frequency (df/dt) - Stage-2

Generator Transformer:

• Generator, Generator transformer, UT overall differential protection (87GT)

• Generator transformer Backup Earth Fault Protection (51NGT)

• Generator transformer Differential Protection (87T)

• HV Restricted Earth Fault Protection (64RGT)

• Over fluxing Relay

• Buchholz Relay

• Winding Temperature

• Oil Temperature

• Pressure Relief Device operation

• Master Trip Relay (86)

• Tripping relays for protection devices of Generator Transformer (GT) and 63X /49X for multiplying the contacts of protections.

For trip function (63X1/49X1)

- GT buchholz II stage (63TX)

- GT winding temperature very high (49 WTX)

- GT oil temperature very high (49 OTX)

- GT pressure relief device operated (63 PTX) ASSAM POWER GENERATION CORPORATION LIMITED 61 THIRD FLOOR,BIJULEE BHAWAN,PALTAN BAZAR,GUWAHARI-01,ASSAM

PRE FEASIBILITY REPORT FOR 1X 660 MW SUPER CRITICAL MAR GHERITA THERMAL PROJECT, DISTRICT-TINSUKIA, ASSAM

- GT fire protection trip (FRTX) for annunciation function (63x2/49x2)

- GT Buchholz I stage (63AX)

- GT winding temperature high (49 WAX)

- GT oil temperature high (490AX)

- GT oil level low (OLAX)

- Cooler supply failure

- Cooler trouble

8.2.7.2 Unit Transformer Protection

• Unit Transformer differential protection (87 UT)

• Unit Transformer Backup earth fault protection on the LV side (51NUT)

• HV inverse time over current Protection (51UT)

• HV Phase Instantaneous Over Current (50UT)

• Restricted Earth Fault Protection (64RUT)

• Buchholz Relay

• Winding Temperature

• Oil Temperature

• Pressure Relief Device operation

• OCTC surge protection.

• Master Trip Relay (86)

• Tripping relays for protection devices of Unit Transformer (UT) and 63X / 49X for multiplying the contacts of protections.

1For trip function (63X1/49X1)

- UT buchholz II stage (63TX)

- UT winding temperature very high (49 WTX)

- UT oil temperature very high (49 OTX)

- UT pressure relief device operated (63 PTX)

- UT fire protection trip (FRTX) ASSAM POWER GENERATION CORPORATION LIMITED 62 THIRD FLOOR,BIJULEE BHAWAN,PALTAN BAZAR,GUWAHARI-01,ASSAM

PRE FEASIBILITY REPORT FOR 1X 660 MW SUPER CRITICAL MAR GHERITA THERMAL PROJECT, DISTRICT-TINSUKIA, ASSAM

2For annunciation function (63x2/49x2)

- UT Buchholz I stage (63AX)

- UT winding temperature high (49 WAX)

- UT oil temperature high (490AX)

- UT oil level low (OLAX)

- Cooler supply failure

- Cooler trouble

8.2.7.3 Station Transformer Protection

• Station Transformer differential protection (87 ST)

• Stationt Transformer Backup earth fault protection on the LV side (51NS) • HV Phase Instantaneous Over Current (50ST)

• Restricted Earth Fault Protection (64RST)

• Buchholz Relay

• Winding Temperature

• Oil Temperature

• Pressure Relief Device operation

• OLTC surge protection.

• Master Trip Relay (86)

• Tripping relays for protection devices of Station Transformer (UT) and 63X / 49X for multiplying the contacts of protections.

1For trip function (63X1/49X1)

- ST buchholz II stage (63TX)

-ST winding temperature very high (49 WTX)

- ST oil temperature very high (49 OTX)

- ST pressure relief device operated (63 PTX)

- ST fire protection trip (FRTX)

ASSAM POWER GENERATION CORPORATION LIMITED 63 THIRD FLOOR,BIJULEE BHAWAN,PALTAN BAZAR,GUWAHARI-01,ASSAM

PRE FEASIBILITY REPORT FOR 1X 660 MW SUPER CRITICAL MAR GHERITA THERMAL PROJECT, DISTRICT-TINSUKIA, ASSAM

2 For annunciation function (63x2/49x2)

- ST Buchholz I stage (63AX)

- ST winding temperature high (49 WAX)

- ST oil temperature high (490AX)

- ST oil level low (OLAX)

- Cooler supply failure

- Cooler trouble

8.2.7.4 3.3 KV Unit auxiliary transformer protection

All transformer protection as applicable for station transformer shall be provided for the unit auxiliary transformer

LT Auxiliary Transformer Protection

For LT Auxiliary Transformer (oil filled) protection system shall be provided with following protective devices

• Over current relay (50/51)

• Earth Fault Relay (50N/51N)

• Restricted Earth Fault Protection (64R)

• Standby Earth Fault (51NT)

• Tripping relays for protection devices of Distribution Transformer and 63X /

49X for multiplying the contacts of protections.

• For trip function (63X1/49X1)

- Buchholz II stage (63TX)

- Winding temperature very high (49 WTX)

- Oil temperature very high (49 OTX)

- Pressure relief device operated (63 PTX)

- Fire protection trip (FRTX)

• For annunciation function (63x2/49x2)

- Buchholz I stage (63AX)

ASSAM POWER GENERATION CORPORATION LIMITED 64 THIRD FLOOR,BIJULEE BHAWAN,PALTAN BAZAR,GUWAHARI-01,ASSAM

PRE FEASIBILITY REPORT FOR 1X 660 MW SUPER CRITICAL MAR GHERITA THERMAL PROJECT, DISTRICT-TINSUKIA, ASSAM

- Winding temperature high (49 WAX)

- Oil temperature high (490AX)

- Oil level low (OLAX)

For Dry type transformer the protective devices shall be as above with modification.

8.2.7.5 Incoming (Source) Breakers.

Each incoming (source) breaker shall be provided with numerical feeder management type devices. These devices shall be multi-element type or multi- function devices comprising of the following protective elements:-

• Over current (50/51) for phase fault with timer (2)

• Over current (50N/ 51N) for earth fault with timer (2)

• Standby earth fault (51SN) (for incomer from transformer only)

• Restricted earth fault (64) (for incomer from transformer only)

• Under voltage with time delay (27)

• VT fuse failure

8.2.7.6 Tie Circuit Breaker

Each tie-breaker shall be provided with –

1. One multifunctional relay comprising of following protective elements

• Over current (50/ 51) for phase fault with timer (2)

• Over current (50N/ 51N) for earth fault with timer (2)

• Under voltage with time delay (27)

• VT fuse failure

2. One numerical synchronizing check relay, if applicable, complete with guard relay and hardwires.

8.2.7.7 Motor Feeder

Each motor feeder shall be provided with –

1. One numerical Motor Protection Relays to detect and take appropriate action against the following

ASSAM POWER GENERATION CORPORATION LIMITED 65 THIRD FLOOR,BIJULEE BHAWAN,PALTAN BAZAR,GUWAHARI-01,ASSAM

PRE FEASIBILITY REPORT FOR 1X 660 MW SUPER CRITICAL MAR GHERITA THERMAL PROJECT, DISTRICT-TINSUKIA, ASSAM

• Thermal over load (49)

• Phase fault (50)

• Unbalance (-Ve seq.)(46)

• Locked rotor (50LR)

2. One Definite time O/C relay (50G) for earth fault (through CBCT)

3. Differential protection (87) for motor rated above 1000 kW rating

8.2.7.8 LT Switchgear

415 Volt PCC

1. The minimum protections to be provided for different types of circuits are listed below:

a. Incoming Feeder: O/C relays (50/51) for phase fault with timer (2) O/C relay (50N/51N) for Earth fault with timer (2). Under voltage relay (27)

b. Outgoing Bkr. Feeder : O/C relays (50/51) for phase fault with timer (2) O/C relay (50N/51N) for Earth fault with timer (2).

2. Apart from protection relays, each electrically operated breaker shall be provided with antipumping (94), trip annunciation (30), lockout (86), lockout supervision (95) and trip supervision (74) relays. Lockout relay shall be hand reset type.

3. Fuse monitoring relay (98) shall be provided on the secondary side of voltage transformer to monitor fuses.

8.2.7.9 415 Volt MCC & DB

1. The minimum protections to be provided for different types of circuits are listed below:

a. Incoming Feeder: O/C relays (50/51) for phase fault with timer (2) O/C relay (50N/51N) for Earth fault with timer (2). Under voltage relay (27)

b. Outgoing motor Feeder: O/C relays (50/51) for phase fault with timer (2) O/C relay (50N/51N) for Earth fault with timer (2).

c. Contactor operated unidirectional motor feeders

• Short circuit protection by HRC fuses.

• Thermal over load relay (hand re set type) with built in single phasing preventer ASSAM POWER GENERATION CORPORATION LIMITED 66 THIRD FLOOR,BIJULEE BHAWAN,PALTAN BAZAR,GUWAHARI-01,ASSAM

PRE FEASIBILITY REPORT FOR 1X 660 MW SUPER CRITICAL MAR GHERITA THERMAL PROJECT, DISTRICT-TINSUKIA, ASSAM

• Adjustable time delay earth fault relay operated from zero sequence

• CTs for motor rated 75kW and only above.

d. Contactor operated valves/ damper feeders

• Short circuit by HRC fuse

• Thermal overload relay (hand re set type)

e. Switch fuse feeders protected by HRC fuses

3. Fuse monitoring relay (98) shall be provided on the secondary side of voltage transformer to monitor fuses.

DC system: Insulation Monitoring Under voltage (27) or no volt relay.

Static microprocessor based relays will be provided as far as possible. All tripping relays will be suitable for operation from 65% to 130% of control supply voltage.

8.2.7.10 400KV Switchyard:

The protective relays shall be numerical type. Relays shall have communicable port for interfacing with SCADA. The functionality of relays for different kinds of feeder will be as follows

a) Outgoing Feeder

• 21 : Distance Protection

• 50/51N : Inverse time over current and earth fault

• 51/51N : IDMT phase over current and earth fault

• 50 LBB : Local Breaker Back up

• 87B : Bus Differential Protection

b) 400 kV GT breaker

• 87 GT : Overall Differential protection of Generator – Transformer

• 87T : Generator Transformer Differential Protection

• 64RGT : Generator Transformer Restricted Earth Fault Protection

• 99GT : Over Fluxing Protection ASSAM POWER GENERATION CORPORATION LIMITED 67 THIRD FLOOR,BIJULEE BHAWAN,PALTAN BAZAR,GUWAHARI-01,ASSAM

PRE FEASIBILITY REPORT FOR 1X 660 MW SUPER CRITICAL MAR GHERITA THERMAL PROJECT, DISTRICT-TINSUKIA, ASSAM

• 50/51 : Instantaneous & IDMT phase over current

• 51N : Inverse time Earth fault

• 87B : Bus differential protection

• 67 : Directional Phase Over current

• 67N : Directional Earth fault

• 50LBB : Local Breaker Back up

c) 400 kV ICT breaker

• 87 ST : Station Transformer Differential protection

• 99ST : Station Transformer over Fluxing Protection

• 50/51 : Instantaneous & IDMT phase over current

• 51N : Inverse time Earth fault

• 64RST : Restricted Earth fault protection for both LV & HV Side

• 51NT : Standby earth fault protection for both LV & HV side

• 87B : Bus differential protection

• 67 : Directional phase over current

• 67N : Directional Earth fault

• 50LBB : Local Breaker Back up

d) Line Reactor

• 87 R : Differential protection relay for Reactor

• 50/51 : Instantaneous & IDMT phase over current

• 51N : Inverse time Earth fault

• 50LBB : Local Breaker Back up

• 21R : Back Impedance Relay

8.2.8.0 Control Room

There will be a centralized control room at the operating floor of steam turbine generator building in which control panels for the steam generator, steam turbine and

ASSAM POWER GENERATION CORPORATION LIMITED 68 THIRD FLOOR,BIJULEE BHAWAN,PALTAN BAZAR,GUWAHARI-01,ASSAM

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generator, auxiliary power supply, will be housed. This will also house the Data Acquisition System equipment and fire alarm control panel.

400KV Switchyard controls will be provided in the switchyard control room. Control panels will be a combination of upright panels and separately mounted control desks with TFT.

8.2.9.0 DC System 8.2.9.1 220V DC system

A separate 220 V DC system for each unit for plant auxiliary system and 01 220 V DC system for switch yard will be provided. Each DC system shall be complete with

02 of 100 % capacity Heavy duty plante (HDP) type battery sets with float and float- cum-boost charges.

DC system will generally supply for the following:

• Emergency Lube Oil Pump, Jacking Oil Pump, etc(DC)

• Emergency Lighting (DC)

• Switchgear Control

8.2.9.2 24V DC System

A separate 24V DC System is considered for Each Unit, comprising battery, battery charger and DC distribution board shall be provided to cater the requirement of DDCMIS system cubicles, cards and transmitters etc.

8.2.9.3 48V DC System

A separate 48V DC System is considered for Switchyard, comprising battery, battery charger and DC distribution board shall be provided to cater the requirement of PLCC system.

8.2.10 Uninterruptible power supply (UPS)

An uninterrupted power supply (UPS) system would be provided to cater to 240V AC, single phase, 50 Hz, 2 wire power supply requirements of instrumentation and control systems viz. man-machine interface equipment, analyzers, receiver instruments of each units, PA & EPBAX system etc.. Separate UPS of sufficient capacity shall be provided for offsite PLC system.

8.2.11 Power and Control Cables

Power cables (AC and DC) will be aluminum conductor, stranded, XLPE insulated, screened, armored and FRLS sheathed. Power cables shall be 11 KV and 3.3 KV UE grade. Control cables will be 1100 volt grade multi-core, stranded, copper ASSAM POWER GENERATION CORPORATION LIMITED 69 THIRD FLOOR,BIJULEE BHAWAN,PALTAN BAZAR,GUWAHARI-01,ASSAM

PRE FEASIBILITY REPORT FOR 1X 660 MW SUPER CRITICAL MAR GHERITA THERMAL PROJECT, DISTRICT-TINSUKIA, ASSAM

conductor, PVC insulated PVC sheathed, armoured and overall PVC/FRLS sheathed with minimum 2.5 mm2 conductor size.

Special cables will be used wherever so required for special applications.

8.2.12 Grounding & Lightning Protection

The system grounding envisages generator neutral earthing through secondary resistance loaded distribution transformer, 400KV system and 415 V system solidly earthed, 11 KV and 3.3 KV neutral earthed through high resistance to facilitate ground fault relaying and transient over-voltage reduction.

A separate grounding system for power plant and switch yard shall be provided for grounding of equipment and structures maintaining step and touch potentials within the safe limits.

However these two systems will be interconnected at appropriate points. Earth mat will be provided throughout the power plant. Separate Earth pits for Electronic earthing, Transformers, Chimney and Cooling Towers etc. shall be provided Lightning protection for building/structures/equipment such as chimney, cooling tower etc. will be provided.

8.2.13 Lighting

Lighting system will be with 240 volt AC for normal lighting and 220 volt DC for emergency lighting. Normal AC lighting will be from 415V AC 3 phase, 4 wire supply through lighting transformers. At least 20% of the normal lighting fixtures will be connected from the emergency lighting distribution board for automatic changeover.

Illumination levels at various places will be according to international practice. Basically indoor illumination will be with fluorescent fittings.

Mercury vapour lamps will be used in areas like the turbine hall. Outdoor illumination will be achieved by Sodium vapour or mercury vapour in combination with flood lights.

8.2.14 Emergency Diesel Generator

To enable the unit to shut down safely during complete AC supply failure in the station, certain important plant auxiliaries will be provided with a reliable AC power supply through a separate source. For this purpose, Emergency Diesel generator station should be provided..

Emergency power derived from the Diesel Generator is used for essential services and safe shut down and battery charging in the event of total black out.

8.3.0 Instrumentation and Controls

ASSAM POWER GENERATION CORPORATION LIMITED 70 THIRD FLOOR,BIJULEE BHAWAN,PALTAN BAZAR,GUWAHARI-01,ASSAM

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Plant Control & Instrumentation provide a simple effective and fail-safe means for reliable and efficient operation of the plant under dynamic conditions and for attainment of maximum station availability. To achieve this objective, Control and Monitoring facilities are designed so that operation of the Boiler, Turbine, and Generator along with their major auxiliaries would be accomplished from a CCR (Central Control Room). From the CCR, operators would start-up, load, unload, release for remote dispatch, shutdown and monitor the steam generator, turbine and other auxiliaries of the plant. To fulfill the above functional requirements, a Distributed Digital Control, Monitoring and Information System (DDCMIS) with TFT / Keyboard operation for SG and TG controls and hard-wired back-up controls with monitoring and controlling devices needed for operation is envisaged. All field instruments like transmitters for Temperature, Flow, Pressure, Level and Differential pressure are of Smart type with HART Protocol.

For systematic and sequential start-up / shutdown and safe operation of Boiler, Burner Management System (BMS) with fail-safe cards has been envisaged and shall be part of DDCMIS.

All the control packages of Turbine-Generator, Boiler and their auxiliaries are preferably of the integral part of DDCMIS and from same family of hardware. In case micro-processor based TG and SG controls are from separate vendors, then the same is hooked-up to DDCMIS through necessary interfacing units.

DDCMIS system configuration Scheme for Unit – I (Typical for Unit – II) & Common System Between two Units are enclosed in the Drawing No:

8.3.1.0 Plant Control & Monitoring Philosophy

The control and Monitoring philosophy envisaged Control from two Locations:

i. From Unit Control Room (UCR)

ii. From Local Control Station for Offsite & auxiliary plants

8.3.1.1 Control & Monitoring From UCR

TFT Operation

i. All equipment associated with the steam generator viz., Burner Management System (BMS), Boiler start up system, Feed water system, Steam temperature Control system (STC), Auxiliary Pressure Reducing and Desuperheating Station (APRDS), HP bypass system, Primary / Secondary air system, fuel oil system, Flue gas system, HP dosing system, Soot Blower System etc., are envisaged to be operable from TFT stations mounted on the Unit Control Desk (UCD).

ASSAM POWER GENERATION CORPORATION LIMITED 71 THIRD FLOOR,BIJULEE BHAWAN,PALTAN BAZAR,GUWAHARI-01,ASSAM

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ii. All equipment associated with Turbine Generator viz, Automatic Turbine Run up System (ATRS), Turbine Electro-hydraulic governing control system(EHG), Automatic Turbine Tester(ATT), LP bypass system, Gland steam control system(GSC), Main steam / Extraction steam system, Condensate system, Heater drains and vent system, LP dosing system, etc., are to be operated from TFT stations mounted on the UCD.

iii. All the balance of main plant equipment, auxiliaries, valves and dampers shall be operable from bank of TFT stations on the UCD.

iv. Selection facility such as Auto / Manual and standby for equipment are provided in the TFT stations.

8.3.1.2 Operation from Hardwired Unit Control Panel (UCP)

i. Steam Generator, Turbine Generator and their Auxiliaries.

ii. In addition to TFT / KBD operation, emergency manual shutdown facility is provided on the Unit Control Panel (UCP) for manual trip of the Steam generator, Steam Turbine and major auxiliaries.

8.3.2 Control & Monitoring from Local Stations

a) Main plant Drives

Local emergency stop push buttons shall be provided for all main plant pumps and fans. Local open / close / stop push buttons with remote / local facility shall be provided as an integral part of valve actuators for all motor operated isolating and bypass valves and dampers, except solenoid valves and solenoid operated drives.

b) Utility Plants

Utilities such as Ash handling system, Instrument / Service air compressors, Coal handling system and Water Treatment Plant shall be operated automatically from PLC based local control systems with serial link to DDCMIS for monitoring.

c) Common Auxiliaries such as CW, ACW, DMCWP, CT fans, Fuel oil system, CW make up system etc. shall be controlled from common DDCMIS provided with Local/remote I/O cabinets as applicable with facility for local/remote control.

8.3.3 Control Processor

Distributed Digital Control, Monitoring and Information System (DDCMIS) shall comprise of Modulating Control, Sequence Control, Interlocking and Protection, Monitoring and Information System, Data Archiving, Performance Calculation, and Operator Interfacing Units.

ASSAM POWER GENERATION CORPORATION LIMITED 72 THIRD FLOOR,BIJULEE BHAWAN,PALTAN BAZAR,GUWAHARI-01,ASSAM

PRE FEASIBILITY REPORT FOR 1X 660 MW SUPER CRITICAL MAR GHERITA THERMAL PROJECT, DISTRICT-TINSUKIA, ASSAM

The micro-processor based distributed digital control system shall have Multi tasking Controllers envisaged in complete redundant mode and has the capability to perform the following tasks either separately or in a combined form:

1) Open loop control (binary)

2) Closed loop control (analog modulating)

3) Plant monitoring/signal acquisition and processing

The micro-processor based system has the capability to perform the above tasks either separately or in a combined form. As multi-function controllers have a number of control functions and are preferred to be in completely redundant mode, security of control functions including those of protection would be maintained even with the loss of the active controller as well as the functions could be taken over by standby controller.

8.3.3.1 Non-redundant Signal Acquisition and Processing Modules for Monitoring

Functions

Primary instruments for monitoring functions are provided separate from those for control tasks. Keeping this segregation of field instruments, the system philosophy could adopt separate controllers for monitoring tasks. Monitoring task being less critical compared to control tasks; the controllers for monitoring could be Non- redundant. Alternatively, as the hardware for monitoring functions is generally similar/ identical to those for the control tasks, it is possible to combine the monitoring portions with control tasks. However, in view of the general practice of control engineering, separate non- redundant controllers shall be provided for this function.

8.3.3.2 Controller Task Allocations

The system has overall control tasks having appropriate redundancy built in for all the system functions both at processor and peripheral level. No failure of any single peripheral or processor leads to any system function being lost.

For the system with multi-function controllers, functional distribution is adopted and geographically, the system can be centralized.

Each functional group consists of dedicated microprocessors including redundancy and dedicated input and output processing. The redundant multifunctional controllers are in a hot back up mode. The back-up controller takes over the function of the failed processor within one loop cycle time.

Following segregation for regulating controls is proposed: -

1) Coordinated controls and Fuel feed control

ASSAM POWER GENERATION CORPORATION LIMITED 73 THIRD FLOOR,BIJULEE BHAWAN,PALTAN BAZAR,GUWAHARI-01,ASSAM

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2) Air flow and excess air correction.

3) Furnace draft.

4) Mill related controls such as air flow/feeder rate/outlet temperature controls.

5) Deaerator level/pressure, hot well level

6) SH steam temperature control

7) RH steam Temperature control

8) HP/LP heaters

9) Secondary air damper control

Segregation further depends upon I/O handling capacity of controller.

Other loops of the plant e.g. miscellaneous loops can be distributed amongst the above controllers.

Each group has sufficient spare capacity of at least 25% to meet modification / extension of the system. Multi-function controllers can incorporate the corresponding interlocks (open loop control tasks of the system). Interlock and modulating controls are to be so assigned to the controllers in such a way that failure of any controller does not lead to shut down of the entire unit.

The loop timing from input status change to output contact actuation does not exceed 50 msecs for protective functions and 100 msecs for the interlock and sequential control tasks.

While allocating control tasks for Interlock Protection, following criteria are also to be satisfied: -

1) Left and right air-flue gas paths do not share controllers.

2) Left and right water paths do not share redundant controllers.

3) Those auxiliaries who are common to both paths will be resident in the controllers of the left / right paths so that both paths will not be lost due to the failure of a controller.

4) The Air and Water paths do not share controllers.

The system has capability to provide held contact, maintained contact or a held contact till completion of the control action. Further system has the capability of either torque or position seating of the valves/dampers.

8.3.3.3 Automation

ASSAM POWER GENERATION CORPORATION LIMITED 74 THIRD FLOOR,BIJULEE BHAWAN,PALTAN BAZAR,GUWAHARI-01,ASSAM

PRE FEASIBILITY REPORT FOR 1X 660 MW SUPER CRITICAL MAR GHERITA THERMAL PROJECT, DISTRICT-TINSUKIA, ASSAM

In addition to the normal protection interlock and sequential control open loop tasks, the control system may be implemented to provide a high degree of automated operation of the plant. The automation system tasks include requisite sequencing for start-up, raising the load to target load, emergency safe shut down etc. under various conditions.

8.3.3.4 Automation System Philosophy

The system envisaged is based on modern network orientation and is totally flexible in its adaptability to process structures, to the safety and availability requirements of main and auxiliary plants and the communication needs of the user.

Typical loop cycle times for critical control loops like Furnace Draft, Feed Water

Control and Air Flow would be < 100 msecs & rest of < 250 msecs.

The control system has the following four functions:-

1) Signal Conditioning (I/O System)

2) Control functions

3) Man-Machine interface

4) System communication

8.3.4 Central Control room

Central Control room will be partitioned into different rooms to house the following equipment:

i. Unit control panel (UCP), Unit Control desk (UCD) and printers (SOE /logging / alarm) in the main control room.

ii. The C&I system cabinet shall consists of electrical auxiliary cabinets, steam generator and turbine auxiliary system cabinets in the unit electronic cubicle room.

iii. Steam and water analyzing system (S W A S) room.

iv. Graphic (Color) printers

v. Character alarm printers

vi. Line printer for logs

8.3.5 Operating Stations

a) Main Control Console

ASSAM POWER GENERATION CORPORATION LIMITED 75 THIRD FLOOR,BIJULEE BHAWAN,PALTAN BAZAR,GUWAHARI-01,ASSAM

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i) The main control console provides the primary man-machine interface through the operator station. In DDCMIS for the Unit – I, the station consists of Seven (6) sets of utility TFTs and keyboards in which two (2) operator station for Boiler & Auxiliaries, Three (3) for Turbine & Auxiliaries and one (1) for Electrical. Four (4) numbers of LVS for monitoring for the unit. The above setup is typical for Unit – II. The TFT units are of interactive type, providing the operator with the ability to issue commands via. Through keyboards. Overview of the plant systems, complete controls and monitoring of the plant equipment and parameters, including performance of start-up/shutdown, normal plant operation and emergency operations, are accessible from any one of the TFT units. In addition, one system is provided for vibrations monitoring system, one system for Burner Management System and one more system for Turbine stress control system (TSC).

Each OWS will consist of Operator Terminals (OT) based on latest PC or Work Station with redundant communication link, 21” Color Graphic (TFT) Monitor, and QWERTY Keyboard and Optical mouse. 1 No. of Color Laser Printer for Graphics, 1 no. of B/W Laser Printer for log and 1 no. of B/W Dot Matrix printer for Alarm are connected in network along with main control consoles.

Equipment status, start permissive check and step-by-step instructions are displayed on the TFT screens for guiding the operator during various plant and equipment start-up and shutdown operations. On a plant fault, system trouble or equipment mal-function, necessary operating instructions are displayed automatically to direct the operator to alleviate the abnormal conditions. These operator guides are of intelligent, easy to follow and designed to enhance plant availability.

ii) Shift Supervisor Station:

The shift supervisor station of Unit – I & II each consists of 1 No. of TFTmonitor, 1 no of Optical Mouse and one Keyboard.

b) C&I Station (Computer Room / Engineer Room):

The computer room/engineer room is located adjacent to the unit control room to provide easy access for control room personnel. This room contains all Distributed Digital Control, Monitoring and Information System (DDCMIS) related equipment necessary for configuring and maintaining the power block as follows:-

i) Main Control Console of the unit consists of one nos of Engineering Station with DVD Read / Writer and one network color laser printer and 1 No. of Performance Calculations System with B/W Laser Printer, 1 No. of Historical Storage and Retrieval System with DVD Read / Writer and 1 no. of B/W Laser Printer, 1 No. of Sequence of Events System with 1 no. of B/W Laser Printer and 1 No. of Smart Transmitter Monitoring Station with B/W Laser Pinter, 1 No. of Continuous Emission

ASSAM POWER GENERATION CORPORATION LIMITED 76 THIRD FLOOR,BIJULEE BHAWAN,PALTAN BAZAR,GUWAHARI-01,ASSAM

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Monitoring System(CEMS), 1 No. of Boiler tube leakage detector system with 1 No. of B/W laser printer,1 No. of SWAS with 1 no. of B/W laser printer for the Unit.

ii) Engineer workstation with 21” TFT / QWERTY Keyboard console and all programming devices for configuration of the system and graphics.

iii) Computer cabinet and Floppy Discs / Cartridge Magnetic Tape / Pen drives for the storage, retrieval, handling and transfer of the system data.

c) Common Unit - BOP

The Common system shall consists of 1 no of Chief Engineer station with one color Laser printer, 2 no’s of Operating station, 1 no of LVS, 1 no of Management Information System with B/W Laser Printer, 1 no of ES System with Color Laser Printer, 1 no. of Historical Storage and Retrieval System, 1 no of Closed Circuit Television, 1 no of OPC client server redundant station and 1 no of ERP station with B/W Laser printer.

8.3.6 Redundancy in I/O

100% redundancy shall be provided for all input/output cards, used for executing closed loop/sequential interlock functions. Redundant cards are not envisaged data acquisition /monitoring functions

Redundancy at following level is provided: -

i. CPU

ii. Bus (Data Highway)

iii. I/O

iv. Power supply

100% redundancy shall be provided for critical I/Os, used for executing closed loop / sequential interlock functions. Redundant cards are not envisaged data acquisition/ monitoring functions.

8.3.7 Steam Generator and Auxiliaries Control

The control system provides a simple effective fail safe means for reliable and efficient operation of the steam generator with its associated auxiliaries for attainment of maximum availability and maintaining plant parametric values at desired controlled levels. The main controls for the steam generator essentially comprise of the following:

1. Coordinated master control system

2. Combustion control

ASSAM POWER GENERATION CORPORATION LIMITED 77 THIRD FLOOR,BIJULEE BHAWAN,PALTAN BAZAR,GUWAHARI-01,ASSAM

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2.1 Fuel flow control

2.2 Air flow control

3. Furnace draft control

4. Feed Water & recirculation control (Boiler start up control)

5. Superheated steam temperature control

6. Reheat steam temperature control

7. Mill Temperature Control

8. CBD tank level control

9. Soot blower system pressure control

10. PRDS control

11. Secondary air damper control

12. Primary Air header pressure control

13. Cold end average temperature control for air preheaters

8.3.8 Binary Controls

Binary logic controls are envisaged for the sequence, protection and interlock operation of major plant auxiliaries. Some of the major auxiliaries / drives are:

1. ID fans

2. FD fans

3. PA fans

4. Mill Systems

5. Seal air fans

6. Reheater protection

7. BMS/FSSS

8. SH/RH spray – block valves and isolation valves

9. LFO, HFO pump

10. Feed water circulating pump/sub cooling control

11. Soot blower control ASSAM POWER GENERATION CORPORATION LIMITED 78 THIRD FLOOR,BIJULEE BHAWAN,PALTAN BAZAR,GUWAHARI-01,ASSAM

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12. Coal Feeder Control

13. Regenerative air heaters

8.3.9 Steam Turbine Generator and Auxiliary Control

For the Steam Turbine Generator, some of the important controls and monitoring requirements are listed below: -

1. Generator slot and bearing temperature measurements

2. Shaft sealing through sealing oil net work

3. Hydrogen cooling system and hydrogen purity monitoring

4. Hot and cold gas temperature monitoring and control

5. Turbo supervisory system

6. ETS /TSC system

7. CW pumps

8. BCW Pumps

9. CEPs

10. BFPs

11. ATRS

12. HP / LP Heaters

13. EHG control System

14. Automatic Turbine Testing (ATT)

15. Turbine Protection System

16. Generator Auxiliaries System

In addition to the above integral controls, the following controls for turbine related auxiliaries are also envisaged for steam turbine & steam turbine generator:-

1. Hot well level control and condensate pumps minimum recirculation

2. Deaerator level control

3. Deaerator pressure control

4. Heaters level control

ASSAM POWER GENERATION CORPORATION LIMITED 79 THIRD FLOOR,BIJULEE BHAWAN,PALTAN BAZAR,GUWAHARI-01,ASSAM

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5. Boiler feed pump minimum recirculation control

6. Auxiliary steam to steam jet air ejector pressure control

7. HP bypass control

8. Gland steam Pressure control

8.3.10 Balance-of-Plant Controls

The following controls for balance of Plant are envisaged:-

1. Fuel oil pumps - outlet pressure and temperature controls

2. Fuel oil tanks - floor coil heating

3. Fuel oil tanks - Suction heating

4. Unit condensate floating tank level

5. DM make up pumps - recirculation

6. Circulating water pumps

7. Auxiliary cooling water pumps

8. Electrical system breakers control and monitoring

9. Condenser online tube cleaning system (COLTCS)

Plant Auxiliaries /Off Side plants shall be operated from their respective local control panels or monitor stations located in the local area control rooms. Some of the auxiliaries will have operational facility from central control room as well as from local panels.

8.3.11 PLC Description

PLC systems shall utilize microprocessor-based controllers. Each controller shall consist of redundant pairs of CPUs (Central Processing Units), each capable of performing the control functions assigned to that functional controller. Each functional controller shall consist of redundant fully capable processors, operating in a "hot standby" mode, with transfer of function to the backup processor in the event of failure of the operating processor. Communications between PLC system and DDCMIS shall be accomplished via an interconnecting communication bus. The communications network shall be provided with redundant communications paths.

8.3.12 Plant Security and Surveillance System (PSS)

A complete integrated plant security and surveillance system (PSS) complete with all hardware and software as required shall be provided. The system shall to be ASSAM POWER GENERATION CORPORATION LIMITED 80 THIRD FLOOR,BIJULEE BHAWAN,PALTAN BAZAR,GUWAHARI-01,ASSAM

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provided include all necessary hardware, software, firmware, interfaces and accessories, all related civil and masonry work required for implementing a fully functional PSS system for a modern power generation utility.

Plant security and surveillance system (PSS) shall be an integrated system comprising the following systems/facilities:

i. Perimeter Intruder Detection System

ii. CCTV Monitoring of Plant area/ equipment

iii. Security card access system

iv. Patrol Guard Monitoring System

1) Perimeter Intruder Detection system

All cameras for perimeter detection system and CCTV system shall be connected to suitably located RTUs (Remote Terminal Units) in groups through single mode Fiber Optic cable for transferring camera video signals. RTUs will then be connected to a network controller which will sit on the plant LAN. Network controllers shall be capable of accommodating number of RTUs. Perimeter intruder detection system shall meet following requirements:

i. The intruder detection system shall be based on video motion detection technology.

ii. Upon detection of intrusion, suitable alarms to be raised to security guards and corresponding camera image shall be displayed on a high resolution dedicated alarm screen.

iii. The system shall allow for the adjusting the sensitivity to reduce false alarms.

iv. When there is no intrusion, the camera images shall be displayed and recorded on a multiplexed basis.

v. The intruder detection system shall be PC based system and will employ a hard disk based recording system.

2) CCTV Monitoring System

Purpose of CCTV monitoring system shall be to meet the following:

i. To provide the plant operators with an overview of the important plant equipment so that they can ascertain that there are no obvious mechanical problems.

ii. To provide another angle on any intruder that may have broken into the premises. Securities personnel may then if required manually track the intruder.

ASSAM POWER GENERATION CORPORATION LIMITED 81 THIRD FLOOR,BIJULEE BHAWAN,PALTAN BAZAR,GUWAHARI-01,ASSAM

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CCTV monitoring system shall meet the following requirements:

i. Simultaneous remote centralized surveillance from both CCR & also from security room.

ii. Display of images in a multiplexed fashion.

iii. Recording of images in a time lapsed fashion and playback facility of images.

3) Security Card Access System

Purpose of the facility is to control access to all vital areas within the important plant buildings by electronic card reader system.

4) Patrol Guard System

Purpose of the system is to ensure that security guards on patrol duty are caring out their duties diligently by recording the visiting time data for different locations.

5) Station LAN

A plant wide Local Area Network (LAN) encompassing the different plant buildings shall be provided. The Station LAN shall interconnect the buildings together and shall facilitate the smooth transfer of Data from one building to the other.

8.3.13 Features of the I & C system

Suitable number of gateways is provided for accepting the DAS inputs from various sub systems.

Smart transmitters (HART Protocol) with turn down ratio 100 or above have been considered.

Transmitters are provided for temperature control loop.

Two out of three logic is implemented for critical loops; and for partial critical loops one out of two logic is applied. For non-critical loops, no redundancy has been envisaged.

For laboratory testing: Laboratory instruments for testing and commissioning are included on selection basis.

For threaded type fittings, swage lock type fixing with double ferrules is used. Field cables are terminated in marshalling panels.

20% wired spare slots are provided in C&I cabinets for future extensions / modifications.

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For signal distribution or fan outs, suitable electronic cards (Opto couplers) as part of DDCMIS system are envisaged.

Field mounted transmitters and analyzers are envisaged to be installed in "Field Instrument Enclosures (FIE)".

The DDCMIS has hardware and software capability (open system) to provide Management Information System. The DDCMIS has capability to store historical data storage and retrieved on cartridge tape drive / Pen Drives.

For interfacing DDCMIS with field instruments, switchgear etc. and for providing contact multiplication, auxiliary relays of suitable rating for output are used.

Displacer type Level transmitters shall be employed for HP / LP heaters and Hotwell level measurements.

HFO / LFO flow meters for boiler are based on Coriolis technology.

All supervisory instruments like recorders, scanners, Totalizer etc are micro- processor based except indicators with built-in alarm facility in scanners only. Recorders are of paperless / chartless type and indicators are of bar graph type.

8.3.14 Major I & C systems Proposed

Apart from above, following major I&C system are also envisaged.

Annunciation System

Sequence of Events Recording System

Vibration monitoring system

Historical Data storage and retrieval (HDSR) System

Condenser online Tube Cleaning (COLTCS) System

Condensate Polishing Plant

Control Valves

Analytical System

Furnace Temperature Probes

Furnace & Flame Viewing System (Flame Cameras)

Fire Detection/Alarm and Fire Proof Sealing System

ASSAM POWER GENERATION CORPORATION LIMITED 83 THIRD FLOOR,BIJULEE BHAWAN,PALTAN BAZAR,GUWAHARI-01,ASSAM

PRE FEASIBILITY REPORT FOR 1X 660 MW SUPER CRITICAL MAR GHERITA THERMAL PROJECT, DISTRICT-TINSUKIA, ASSAM

Instrumentation Pipes/Tubes and Fittings

Air supply for Pneumatic Equipment

Cables

Erection Hardware and cables

Control and Instrumentation Laboratory

Earthing

Spares

8.3.15 Plant Communication System

The plant will be provided with effective and reliable communication with intercommunication system and internal telephone system. The intercommunication system will have both private and paging modes with handsets located at various strategic points.

The plant Communication System will consist of the following:

i. Public Address System.

ii. Telephone systems complete with EPABX, telephone sets in the Power Plant and associated administration buildings.

iii. Walky-talkies for the plant communication with base station.

8.3.16 Training

All Equipment / Instrument contractor will be responsible for providing training to employer’s personnel on offered systems at contractor’s works/contractor’s associate’s works. It shall include training operators in the use of system, in the programming and hardware maintenance of the equipment to the extent that the Employer’s personnel can make corrections and changes to the systems programs and maintains the system’s hardware.

The maintenance and operator training shall include lectures and hands on experience on a similar type of equipment/system at manufacturers’ works and site and/or training simulator. The details of hardware and software training shall be as finalized during detailed engineering and shall be subject to employer’s approval.

8.4.0 Civil & Structural Works 8.4.1 Plant Grading

ASSAM POWER GENERATION CORPORATION LIMITED 84 THIRD FLOOR,BIJULEE BHAWAN,PALTAN BAZAR,GUWAHARI-01,ASSAM

PRE FEASIBILITY REPORT FOR 1X 660 MW SUPER CRITICAL MAR GHERITA THERMAL PROJECT, DISTRICT-TINSUKIA, ASSAM

Elevation of the site is varying from around 150 m to 236 m from eastern side to western side. The final grade level of the plant will, however be decided after detailed contour survey of the area at a later date.

8.4.2 Seismic Consideration

The power station area is located in Seismic Zone - V as per the demarcation of IS: 1893 - 2002 of Indian code of practice. Analysis and design of structures to resist the seismic forces would be carried out as per the provisions stipulated in the code. The applicable important factors would be duly considered in the design.

8.4.3 Wind Condition

The maximum wind pressure including winds of short duration as specified in Indian Standard Code of Practice IS: 875 (latest revision) would be adopted for the zone. The provision of Indian Standard Code of Practice IS: 875 with appropriate coefficient for variation of heights and shape will be considered for design.

8.4.4 Civil Works

A preliminary soil investigation is being carried out by the APGCL at the proposed site. Based on the nature of comparatively low bearing capacity of the soil and undulated ground anticipated in the region, following foundation systems are being recommended:

a) All major structures including machine foundations will have pile foundations.

b) Foundations for lightly loaded structures may rest on isolated/mat/pile foundations depending upon the height of fill and compactness, if found suitable after soil investigation.

Plant civil works shall comprise of plant layout, micro-grading, geo-technical investigation, in-plant roads and drains (Storm, plant drains) in plant area, Boiler & auxiliaries foundations, ESP foundations, transformer foundations, milling building,FGD,limestone storage & feeding building, limestone milling house, foundation for limestone conveyor galleries & transfer house, ID duct foundations, FAN (ID, FD, PA etc) foundations, Concrete paving (Transformer yard to Chimney), twin flue RCC chimney of 275 m height, including forced vegetation, lift, electrical works, wind tunnel study, transformer yard civil works including rails, fencing and oil water separator and oil pits, providing railway line within the plant area, CW ducts-CW pump house to cooling tower, Cooling towers, cooling tower switchgear rooms, pipe and cable trestles, cable trenches/duct banks, civil works for all below & above ground piping including CW pipe, Sewerage system (septic tanks and soak pits), Fire station, Drill tower etc.

8.4.5 Complete Civil, Structural & architectural Works includes the following:

ASSAM POWER GENERATION CORPORATION LIMITED 85 THIRD FLOOR,BIJULEE BHAWAN,PALTAN BAZAR,GUWAHARI-01,ASSAM

PRE FEASIBILITY REPORT FOR 1X 660 MW SUPER CRITICAL MAR GHERITA THERMAL PROJECT, DISTRICT-TINSUKIA, ASSAM

• Power house, Miscellaneous bays, control tower

• Mill & Bunker bay

• Service building

• Coal handling plant, loco shed

• ESP control rooms

• Ash handling plant including Ash Pond

• Fuel oil storage area, pump house, unloading

• Water treatment plant, clarified water pump house

• DG building, DG foundation

• Compressor house

• Air washer rooms

• Fire water pump house

• Cooling water pump house with forebay

• Raw water reservoir, pump house

• DM plant, Chlorination plant, Hydrogen plant, effluent treatment plant, Central Monitoring Basin

• Any other civil structural architectural works (including temporary works) required from system point of view only will be provided.

8.4.6 Main Plant Building & structures 8.4.6.1 Main Power House including Electrical Control Building

All the main plant columns are to be supported on pile foundations, according to the soil data. The grade of concrete shall be M-25.

8.4.6.2 Turbo Generator and other major Equipment Foundations

The Turbo-Generator shall be supported on a RCC deck at the operating floor level. The RCC deck in turn, shall be supported on vibration isolation system consisting of helical springs and viscous dampers. The vibration isolation system shall rest on RCC columns which shall in turn rest on RCC base raft. The LP condenser below the LP turbine shall also rest on the same RCC base raft.

ASSAM POWER GENERATION CORPORATION LIMITED 86 THIRD FLOOR,BIJULEE BHAWAN,PALTAN BAZAR,GUWAHARI-01,ASSAM

PRE FEASIBILITY REPORT FOR 1X 660 MW SUPER CRITICAL MAR GHERITA THERMAL PROJECT, DISTRICT-TINSUKIA, ASSAM

The top deck directly supporting the Turbo-Generator shall be grade M30. RCC columns and beams shall be of grade M30. The RCC base raft of the TG foundation shall rest on piles.

8.4.6.3 Other Equipment Foundation

The Boiler Feed Pumps (TDBFP & MDBFP), ID, FD & PA fans and Coal Mills shall also be supported on RCC top deck which in turn shall be supported by springs cum viscous dampers (Vibrating Isolation System). Spring supported foundations shall also be provided for coal crushers (both primary & secondary). The spring- cum viscous dampers shall in turn rest on RCC raft/strip foundation supported on piles.

The grade of concrete for top deck of boiler feed pumps, fans and mills shall be M25 and that for the raft/strip footing shall also M25.

All main plant foundations shall be on piles. Piles of 600 mm diameter with allowable carrying capacity of 65 T for each pile in compression are proposed. Based on the available geotechnical data, minimum pile lengths vary from 22 m to 25 m. The actual load carrying capacity of piles shall be ensured during detailed design and also from field load tests by conducting initial load test on test piles.

8.4.6.4 Geo-technical Investigation

For the proposed power plant geotechnical investigation is yet to be done. It is envisaged that shallow foundation may be provided for minor structures and for major equipments and structures, pile foundations may be provided. Cast in situ piles shall be of RCC with grade of concrete as M25. In case the actual ground conditions are found to be different during detailed investigation stage, type of foundation and the quantity may have to be reassessed. The chemical analysis of the sub-soil and water are not done at this stage.

8.4.6.5 Plant roads

The main plant road shall be 100 m wide. All Double lane roads shall be of 7.0 m wide concrete with 2.5 m wide shoulders on both sides of the road. Single lane roads shall be of 4 m wide black topping and 2.5 m wide shoulders on both sides of the road. Access roads to building/facilities shall generally be single lane roads without shoulders. Concrete Roads inside the main plant area and black topping roads for peripheral area are preferred.

8.4.7 Main Plant Civil Works 8.4.7.1 Structural System

Main plant complex shall consist of the following buildings and facilities.

a) Main Power house

ASSAM POWER GENERATION CORPORATION LIMITED 87 THIRD FLOOR,BIJULEE BHAWAN,PALTAN BAZAR,GUWAHARI-01,ASSAM

PRE FEASIBILITY REPORT FOR 1X 660 MW SUPER CRITICAL MAR GHERITA THERMAL PROJECT, DISTRICT-TINSUKIA, ASSAM

b) Control Tower Block

c) Mill/Bunker Building

d) Coal conveyor galleries and transfer points in Boiler area

e) Trestle supports for cables and pipelines

f) Auxiliary buildings including Compressor house, DG set building, ESP control room building, air washer room, etc. The layout and general arrangements details of the main plant shall be given.

8.4.7.2 Main Power House

This shall be a framed structure consisting of structural steel columns and beams. This building shall be independent. Structures supporting platforms and floors around T.G and electrical bay shall be structural steel columns and beams.

EOT cranes shall be provided in T.G Bay. One number elevator for passenger shall be provided for Main Power House.

Civil foundation shall take into consideration soil bearing capacity, water table and loading. Minimum grade of concrete for various works shall be generally used as per IS: 456.

Table 8.5 Concrete Mix Type of structure / Grade Fill concrete

Blinding layer below foundations, trenches and under ground structures, foundation below brick wall, etc. Minimum thickness of layer shall be 75 mm Plinth protection work around buildings

Base plate encasement, encasement of structural steel work, all RCC paving work, ground floor slabs, cable and pipe trenches, etc.

All RCC structures and equipment foundations, super structure, grade beams, columns, roof slabs, TG foundations, transformer foundations and all underground RCC structures, cable and pipe rack foundation, pedestals, etc. water retaining structures below and above ground, TG top deck, boiler foundations, mill foundations, precast concrete work, crusher foundations, etc.

ASSAM POWER GENERATION CORPORATION LIMITED 88 THIRD FLOOR,BIJULEE BHAWAN,PALTAN BAZAR,GUWAHARI-01,ASSAM

PRE FEASIBILITY REPORT FOR 1X 660 MW SUPER CRITICAL MAR GHERITA THERMAL PROJECT, DISTRICT-TINSUKIA, ASSAM

Inter mixing of different grade of concrete in the same structure shall not be allowed normally. However in the case of structures like RCC chimney, natural draft cooling towers, etc. different mix will be permitted at different levels.

Reinforcement bars shall be as per the following codes:

Table 8.6

High Yield Strength Deformed bars IS: 1786

Mild steel bars Grade I of IS: 432

Welded wire fabric IS: 1566

8.4.8 Control Tower

The control tower shall be a separate block projecting out from BC bay towards boiler from the electrical bay. This shall be made of structural steel frame. One number elevator for passenger shall be provided for service building.

8.4.9 Mill / Bunker Building

There shall be one mill / bunker building located on one side of boiler. This building shall accommodate mills. This shall have intermediate floors for feeder and tripper. Mill and bunker building shall be braced steel structure in longitudinal as well as transverse direction. Bunkers shall be made of structural steel having stainless steel lining at the bottom portion. Bunker size shall be designed for a capacity corresponding to 12 hrs consumption of coal, besides 4 hours dead storage.

8.4.10 Conveyor galleries and Transfer Points

Overhead conveyor galleries shall be of structural steel frame with powder coated 0.6 mm galvanium sheets roofing and cladding provided between ESP and boiler area. Chequered plate walk ways shall be provided. Transfer points and intermediate supporting trestles shall be made of braced steel framed structures.

8.4.11 Cable and Pipe Racks

Structural steel trestles shall be provided for supporting overhead cables and pipe lines of fuel/water supply in the main plant and outlaying areas. However, for below ground routing, RCC trench with removable pre cast cover slabs shall be used.

8.4.12 Auxiliary Buildings

All the auxiliary building in the main plant area mentioned above shall generally be made of RCC framed structure with in filled brick walls. Open (shallow) foundation system has been envisaged for these buildings.

ASSAM POWER GENERATION CORPORATION LIMITED 89 THIRD FLOOR,BIJULEE BHAWAN,PALTAN BAZAR,GUWAHARI-01,ASSAM

PRE FEASIBILITY REPORT FOR 1X 660 MW SUPER CRITICAL MAR GHERITA THERMAL PROJECT, DISTRICT-TINSUKIA, ASSAM

8.4.13 Floors and Walls

Roof AB bay of main power-house shall be provided with cold formed troughed steel sections used as covering cum permanent shuttering over which either foam concrete or RCC slab would be placed. All other roofs and floors shall be made of RCC slab.

External cladding of main plant building other than transfer points shall be of brick masonry having minimum one brick thickness. All the partition walls shall also be of brick masonry. Corrugated galvanized M.S. Sheet shall be provided for cladding of transfer points. However internal partition in control tower shall consist of glazed aluminium.

8.4.14 Architectural and Finishing Works

External and other finishes shall be decided based on good aesthetic and architectural considerations. The operating floor of main power house shall be finished with heavy duty concrete tiles (Carborundum tiles). Unit control rooms, control equipment rooms and ESP control room shall have flexible PVC tile flooring. Computer room shall have particle board false flooring. Acid resistant tiles shall be used in battery room floor. Terrazzo flooring shall be provided for entrance area, staircase, entrance lobby, office areas and toilets. All other floor areas shall generally be finished with metallic hardener topping. Combination of resin bonded granular textured finish (Vineratex) and sandtex matt paint shall be used for external finish. Inside wall of unit control room shall be provided with white marble tiles. All main doors shall be made of aluminium (glazed). All control rooms shall have doors windows and partitions made of glazed aluminium. Ceiling shall be white washed and internal wall faces shall receive distemper/acrylic emulsion paint. Steel structures shall be finished with chemical resistant paint on account of marine environment. Unit control room shall be provided with permanently colour coated lineal aluminium false ceiling. All air conditioned areas shall be provided with pre-laminated particle board false ceiling. Boiler area shall be provided with RCC paving with metallic hardener topping.

8.4.15 Chimney

A multi flue reinforced Concrete Chimney is preferred from environmental consideration, inspection and maintenance advantages and construction ease. The flue gas emission point shall be 275 Mts above the plant ground level. External cage elevator (electric driven) will be provided for construction and maintenance. The chimney windshield would be of RCC with slip form method of construction. The chimney shaft will be of RCC with slip form construction on a RCC raft foundation. As per statutory requirements, aircraft warning light and lighting electrodes etc., on the top of the chimney would be provided.

ASSAM POWER GENERATION CORPORATION LIMITED 90 THIRD FLOOR,BIJULEE BHAWAN,PALTAN BAZAR,GUWAHARI-01,ASSAM

PRE FEASIBILITY REPORT FOR 1X 660 MW SUPER CRITICAL MAR GHERITA THERMAL PROJECT, DISTRICT-TINSUKIA, ASSAM

Liner (flue) shall be constructed from structural steel and shall be hung from the liner support platform near the Chimney top. The liner shall be provided with resin bonded wool type thermal insulation.

The portion of the liner protecting above the Chimney roof shall be of stainless steel. Intermediate internal platform shall be provided for enabling access to various elevators of the stack and to provide lateral restraint to the steel liner.

The structural steel transition inlet ducting shall be bottom supported. This transition ducting shall be suitably profiled from a rectangular shape at the chimney inlet to a circular shape inside the chimney where it shall be connected to the suspended circular steel liner through suitable (non-metallic) fluro elastometric fabric expansion compensators. Transition ducting shall also be thermally insulated. Fabric expansion compensators shall be installed after the transition ducts have been erected.

Internal platform shall be structural steel construction and shall be supported from the wind shield. The floors/walkways shall be of chequered plate construction. The chimney roof shall, however comprise of a reinforced concrete slab supported over a grid of structural steel beams. The roof slab shall be protected by a layer of acid resistant tiles. The grade level slab shall be of reinforced concrete with a metallic hardener floor finish.

An internal structural steel staircase, supported from the shell wall, shall be provided for full height of the stack. This shall provide access to all internal platforms giving ample access to various elevations of the chimney. The stair treads shall be fabricated from chequered plates.

The top external portion of the wind shield shall be coated with acid and heat resisting paint in alternate bands of colors red and white to meet the aviation safety requirements. The mini-shells and the top few meters of the internal surface of the wind shield shall be painted for acid and heat protection with bituminous paint.

The other components of the chimney include a large roll-up door and a personnel access door at grade level, doors at all platform levels, a personnel access hatch in the roof slab, liner hatches, liner test ports, rain water drainage system, flue liner drainage system, louvers with bird screens for ventilation openings, electrical power supply, distribution boards, socket outlets, power and control cabling, raceway system, stair and platform lighting, lightning protection and grounding system, aviation obstruction lighting and communication system. Provisions shall be made for a proven rack and pinion elevator or any other type of elevator. All mild steel components shall be protected by a durable painting system.

Mild steel discrete strakes shall be provided, at the top (usually 1/3rd height) if found necessary from design requirements. The super structure shall be supported on a foundation system with piles.

ASSAM POWER GENERATION CORPORATION LIMITED 91 THIRD FLOOR,BIJULEE BHAWAN,PALTAN BAZAR,GUWAHARI-01,ASSAM

PRE FEASIBILITY REPORT FOR 1X 660 MW SUPER CRITICAL MAR GHERITA THERMAL PROJECT, DISTRICT-TINSUKIA, ASSAM

8.4.16 Coal Handling System

Coal shall be transported from nearby NECL to Plant site through rail. Two nos. wagon tipplers & one no. underground track hopper is proposed. Thereafter it shall be conveyed to coal handling plant area by use of closed belt conveyors by providing necessary transfer points, conveyor galleries, etc. Conveyor galleries, trestles, superstructure of crusher house and transfer houses will be of fabricated steel structure. Intermediate floors and roofs in transfer houses and crusher house will be of plastered brick/hollow block work / AC sheets and necessary windows louvers will be provided for natural lighting and ventilation. RC crusher foundation will have vibration isolation system from the crusher house building. Conveyor galleries will be of concrete box section with provision of appropriate water proofing arrangement.

The coal stock pile area is proposed to be provided with compacted grade having slope and drainage system. The coal bunkers housed between turbine building and boiler will be of structural steel frame with mild steel skin plate having stainless steel lining in the bottom portion of the hoppers.

8.4.16.1 Transfer Points

Transfer point will be provided at every change of direction of the conveyors and at all elevation change points. This will have structural steel frame work with R.C.C. roof and floors. Cladding shall be of metal sheeting

8.4.16.2 Conveyor Galleries

Overhead pipe conveyors are proposed. If belt conveyors, overhead conveyor galleries will be of structural steel frame with powder coated 0.6mm galvanium sheets roofing and cladding. Walkways are to be provided at sides and in between conveyors. The galleries will be supported on steel trestles which will have RCC/Pile foundation.

8.4.17 Fuel Oil Handling System (Civil Works)

The following civil works are to be provided for the Fuel Oil handling System.

• Pump house to have heaters, pressurizing pumps etc.

• A raised ramp for unloading the fuel oil from road tankers

• Foundations for storage tanks

• RCC dyke wall around the tank area.

• Miscellaneous foundations for pumps, pipe racks, pipelines etc.

8.4.18 DM plant, Filter house & R.O Plant

ASSAM POWER GENERATION CORPORATION LIMITED 92 THIRD FLOOR,BIJULEE BHAWAN,PALTAN BAZAR,GUWAHARI-01,ASSAM

PRE FEASIBILITY REPORT FOR 1X 660 MW SUPER CRITICAL MAR GHERITA THERMAL PROJECT, DISTRICT-TINSUKIA, ASSAM

Demineralization plant building shall be framed RCC Structure with in filled brick work. The concrete shall be of M-20 grade for all super structural work. The adequate size of the building shall be provided.

Underground RCC neutralization pit shall be constructed in two compartments with concrete of grade M-25. Required size of neutralization pit shall be provided. The inside face of pit shall be provided with acid/alkali resistant lining.

Condensate polishing unit, degasser and acid storage tanks being outdoor type installations. Only raft foundation along with dyke wall is envisaged. This shall be of RCC with concrete of grade M25. Adequate size of the building shall be provided.

The foundation for 1 No.of D.M tank shall be of RCC of grade M-25.The diameter of ring beam for supporting the tank shall be about 13.4 m.

A filter house cum filter water pump house building shall be constructed to house 2 gravity filters. The building shall be of RCC framed structure of grade m-25.Reverse Osmosis building shall be RCC framed structure of concrete of grade M20. The adequate size of the building shall be provided.

The foundation for 2 Nos of Reverse Osmosis water tanks shall be constructed of RCC of grade M-25. The dia. of the ring beam shall be about 13 m.

8.4.19 Cooling Water System

Buridihing River Water is proposed to be used for the CW system, protection of concrete and steel shall be provided. This shall include use of dense and durable concrete (M-25) with plasticizer cum water proofing agent, use of sulphate resistant cement, coating of reinforcement etc.

All steel pipes used in CW system will be gunnited with a minimum thickness of 50 mm. CW ducts would be lined with concrete on both inside and outside surface. Minimum thickness of outside concrete layer shall be 75 mm. Alternately GRP pipes and ducts can be used in CW system.

8.4.20 Raw Water System

A RCC raw water reservoir shall be provided with adequate capacity for storing sweet water requirements. One number raw water pump house shall be provided. Pump house shall be provided to the potable water reservoir for potable water supply. Sub-structure of the pump houses shall be of RCC while super structure shall be of steel with in filled brick panel walls and RCC cast-in- situ roofing over permanent metal decking.

In addition to the above one RCC fire water reservoir of 500 cu.m capacity shall be provided in plant area for fire water storage. One no. fire water pump house shall be provided adjacent to the reservoir which will house fire water pumps. Sub-structure ASSAM POWER GENERATION CORPORATION LIMITED 93 THIRD FLOOR,BIJULEE BHAWAN,PALTAN BAZAR,GUWAHARI-01,ASSAM

PRE FEASIBILITY REPORT FOR 1X 660 MW SUPER CRITICAL MAR GHERITA THERMAL PROJECT, DISTRICT-TINSUKIA, ASSAM

and super structure of the pump house shall be similar to that of the above referred pump house.

8.4.21 Switchyard

Switchyard structures including equipment supports will be of galvanized steel. The foundations will be RCC spread footing. Cable trench, pits etc. will be of RCC with precast RCC covers. Peripheral and internal roads will be provided for access during equipment maintenance. The entire area will be enclosed with suitable safety fencing and control gate.

8.4.22 Ancillary Buildings

Ancillary building such as service building, electrical switchgear room building etc. shall be provided. These buildings shall generally be constructed of RCC frame work with infilled brickwork. Service building shall be separated from Main TG building, at least by 10 to 20 feet with partition wall to avoid noise.

8.4.23 Rain Water harvesting Scheme

Suitable rain water harvesting scheme acceptable to National Ground Water

Authority shall be provided for main plant building and other major building.

ASSAM POWER GENERATION CORPORATION LIMITED 94 THIRD FLOOR,BIJULEE BHAWAN,PALTAN BAZAR,GUWAHARI-01,ASSAM

PRE FEASIBILITY REPORT FOR 1X 660 MW SUPER CRITICAL MAR GHERITA THERMAL PROJECT, DISTRICT-TINSUKIA, ASSAM

SECTION - 9

ENVIRONMENTAL CONSIDERATIONS

9.1.0 The proposed power plant of 1 x 660 MW will be coal fired. A coal fired thermal power station can contribute to environmental pollution in the following manner:

a) Atmospheric pollution through particulate and gaseous emissions

b) Thermal pollution of the surroundings

c) Discharge of solid and liquid wastes

d) Noise pollution

Type & Source of Pollution

Table 9.1 SL no Type Source of Pollution 1 Air pollution • Particulate Matter in flue gas

• Sulphurdioxide in flue gas

• Nitrogenoxides in flue gas

• Coal dust particles during storage/handling

• Dust in the ash disposal area 2 Water &Sewage Effluent from ash disposal area pollution Effluent from water treatment plant(WTP) Steam generator blow down Cooling tower blow down Plant drain • Domestic Sewage

• Effluent from coal pile area runoff

3 Noise Pollution Steam turbine generator

• Other rotating equipment

• Combustion induced noises

• Flow induced noises

• Steam safety valve

4 Solid Waste Ash Management

ASSAM POWER GENERATION CORPORATION LIMITED 95 THIRD FLOOR,BIJULEE BHAWAN,PALTAN BAZAR,GUWAHARI-01,ASSAM

PRE FEASIBILITY REPORT FOR 1X 660 MW SUPER CRITICAL MAR GHERITA THERMAL PROJECT, DISTRICT-TINSUKIA, ASSAM

9.2.0 ENVIRONMENTAL PROTECTION AND POLLUTION ABATEMENT 9.2.1 GENERAL

Environmental protection and the control of solid, liquid and gaseous effluents or emissions are key elements in the design of all steam power generating systems. The emissions from thermal power plants are regulated by State and Central Governments.

Minimizing aqueous discharges and safely disposing of solid by-products are key issues for power projects.

Atmospheric emissions arise primarily from the by-products of the combustion process SO2, NOx, particulate fly ash, volatile organic compounds (VOC) and some trace quantities of other materials and are exhausted from the stack. Another source of air emissions is the cooling tower and the associated thermal rise plume, which contains heat and some trace materials along with the water vapour.

Aqueous discharges arise from following sources: cooling tower blow down, boiler chemical cleaning solutions, gas side water washing waste solutions, as well as a variety of low volume wastes including ion exchange regeneration solutions from the Water treatment Plants, boiler blow down, sewerage system discharges from buildings and plant floor drains.

9.2.2 PARTICULATE MATTER AND GASES

The elements polluting the air that are discharged from the proposed PP are:

• Dust particulate from fly ash in flue gas

• Nitrogen oxide in flue gas

• Sulphur-di-oxide in the flue gas

Electrostatic precipitators are proposed for the steam generator, to contain the dust emission from plant to a level less than 25 Mg/Ncum. The height of the stack for the boiler, which disburses the pollutants, has been fixed at 275 meters. This is based on maximum sulphur content in coal of 1.5% to 4% and average GCV of 5500 kcal/kg.

Due to high content of sulphur in NEC coal especially Margherita coal FGD technology has be considered for implementation to extract the Sulphur from flue gases.

9.2.2.1 FLY ASH AND FURNACE BOTTOM ASH

Fly ash collected from the ESP hoppers and the air heater hoppers and the ash collected from the furnace bottom hoppers will be collected by a pneumatic or vacuum ash handling system and stored in day silos.

ASSAM POWER GENERATION CORPORATION LIMITED 96 THIRD FLOOR,BIJULEE BHAWAN,PALTAN BAZAR,GUWAHARI-01,ASSAM

PRE FEASIBILITY REPORT FOR 1X 660 MW SUPER CRITICAL MAR GHERITA THERMAL PROJECT, DISTRICT-TINSUKIA, ASSAM

9.2.3 WATER POLLUTION 9.2.3.1 EFFLUENT FROM WATER TREATMENT PLANT

Hydrochloric acid and sodium hydroxide will be used as regenerants in the proposed strong acid cation exchanger, strong base anion exchanger and mixed bed polisher of the water treatment plant. However, the quantity of these chemicals used will be low and the frequency very less due to the fact that the regeneration is only for the Mixed Bed. Since the water treatment plant will be based on the RO principle, the requirement of the chemicals will not be same as that of a conventional demineralisation plant. The acid and alkali effluents generated during the regeneration process of the ion-exchangers would be drained into an epoxy lined underground neutralizing pit. Generally, these effluents are self neutralizing. However provisions will be made such that the effluents will be neutralised by addition of either acid or alkali to achieve the required pH of about 7.0. The effluent will then be pumped into the effluent treatment ponds.

Apart from the regenerates discharged to the neutralising pit, the RO discharges the reject water, which has higher TDS. This also will be let into the neutralising pit and the RO discharge will be diluted with the blow down from the cooling tower and the other discharges before letting the same out to the effluent treatment plant.

9.2.3.2 STEAM GENERATOR BLOW DOWN

The salient characteristics of blow down water from the point of view of pollution are the pH and temperature of water since suspended solids are negligible. The pH would be in the range of 9.8 to 10 and the temperature of blow down water will be 100 ºC.

9.2.3.3 WASTE WATER TREATMENT

Wastewater treatment for the plant will be based on discharges of the various wastewaters to ponds for clarification and filtration. Oily water will be treated separately to remove Oil / Grease before discharge into effluent ponds. The oily water collection in the plant is basically due to floor cleaning, leaky oil filters, etc.

Clarification is used to settle out large suspended particles and condition smaller colloidal particles to make them settle. A reservoir tank is used to allow larger particles to settle in a matter of hours. The finer particles overflow and are made to settle more quickly by the addition of chemical agents, coagulants and polymers that cause agglomeration to sizes large enough to settle out of suspension.

Filtration will be made to a porous barrier across flowing liquid to remove suspended materials. Filtration can be used to supplement clarification and permits reducing suspended solids to the parts per billion levels.

ASSAM POWER GENERATION CORPORATION LIMITED 97 THIRD FLOOR,BIJULEE BHAWAN,PALTAN BAZAR,GUWAHARI-01,ASSAM

PRE FEASIBILITY REPORT FOR 1X 660 MW SUPER CRITICAL MAR GHERITA THERMAL PROJECT, DISTRICT-TINSUKIA, ASSAM

As required and with approvals from appropriate regulating bodies, combining various plant streams to provide a neutral pH product controls final waste stream pH. Where needed, acid or alkali addition will be used to achieve the final pH.

9.2.4 THERMAL POLLUTION

Natural Draft cooling water system has been proposed. This eliminates the letting out of high temperature water into the canals and prevents thermal pollution. Blow down form the cooling tower will be trenched out and ultimately conveyed to the effluent ponds. Hence there is no separate pollution on account of blow down form cooling water system.

9.2.5 NOISE POLLUTION

The rotating equipment in the PP will be designed to operate with a total noise level of not exceeding 85 to 90 db (A) as per the requirement of Occupational Safety and Health Administration (OSHA) Standards. The rotating equipments are provided with silencers wherever required to meet the noise pollution. As per OSHA, protection form noise is required when sound levels exceed those given in the following table.

9.2.5.1 PERMISSIBLE NOISE LEVELS

Table 9.2 Exposure Duration / Day Sound Level db(A) 8 90 6 92 4 95 3 97 2 100 1 102

9.2.6 MONITORING OF EFFLUENTS

The characteristics of the effluents from the proposed power plant will be maintained so as to meet the requirements of State Pollution Control Board and the minimum standards and thereby assure that the air quality is maintained within the prescribed within the prescribed levels.

The following will be monitored form the stack emissions.

• Suspended Particulate Matter

• Sulphur-Di-Oxide

ASSAM POWER GENERATION CORPORATION LIMITED 98 THIRD FLOOR,BIJULEE BHAWAN,PALTAN BAZAR,GUWAHARI-01,ASSAM

PRE FEASIBILITY REPORT FOR 1X 660 MW SUPER CRITICAL MAR GHERITA THERMAL PROJECT, DISTRICT-TINSUKIA, ASSAM

The Laboratory attached to the PP will be equipped with the necessary instruments for carrying out air quality monitoring. It is also proposed to monitor the particulate emission at the stack to keep a continuous check on the performance of the ESP. Adequate sampling openings will be provided in the stack.

9.2.7 IMPACT OF THE POLLUTION ON THE ENVIRONMENT

As all the necessary pollution control measures to maintain the emission levels of dust and SO2 are taken and other effluents will be treated in the effluent treatment plant, there will be no adverse impact on either the air or water quality in around the PP site on account of the installation of the plant.

Other provisions for pollution on line monitoring and control to ensure compliance

9.2.8 RESETTLEMENT & REHABILITATION

Government of India has recently formulated the National Rehabilitation and Resettlement Policy 2007which has wider social implication.

The major objectives of the Policy are as follows:

• To minimize displacement and to promote, as far as possible, non-displacing or least-displacing alternatives;

• To ensure adequate rehabilitation package and expeditious implementation of rehabilitation with active people’s participation

• To protect the rights of weaker sections, especially members of SCs and STs.

• To provide better standard of living and to ensure sustainable income to affected families

• To integrate rehabilitation concerns into the development planning and implementation process

• To facilitate harmonious relationship between the body which acquires land and the affected families through mutual cooperation.

The site of the proposed power plant is highly undulated with ridges and valleys covered with tea plantation & forest. For cultivated land requires R & R, this will not cause any impact for the project implementation with the requirements of the State Environment Conservation Board will be made.

9.2.9 Green Belt Development:

With a view to attenuate air pollutants, fugitive dust, to absorb noise and to care of uptake of water pollutants if any, it is recommended to develop a greenbelt all around the boundary and at several locations within the proposed power plant premises.

ASSAM POWER GENERATION CORPORATION LIMITED 99 THIRD FLOOR,BIJULEE BHAWAN,PALTAN BAZAR,GUWAHARI-01,ASSAM

PRE FEASIBILITY REPORT FOR 1X 660 MW SUPER CRITICAL MAR GHERITA THERMAL PROJECT, DISTRICT-TINSUKIA, ASSAM

Green belt shall be developed along the boundary of the project site. Since the site area of the proposed power plant consists of consists of hillocks, hills and valleys, much excavation will be required for grading the land at different levels. Green belt will prevent the soil erosion and improve the soil stabilization.

The thick vegetation in the plant premises will also attenuate continuous noise.

Adequate green belt would be developed in and around the project area and the ash disposal area satisfying the requirement of state as well as Central Pollution Control Board (CPCB). Plantation near coal stacks and the ash disposal area to arrest fugitive dust are also proposed. A separate study to select appropriate type of trees and plants suitable for this region would be taken up in the detail engineering stage. These green belts, apart from stopping soil erosion, arresting air-borne dust particles and acting as noise- barrier, would help in improvement of ecology and aesthetics of the area.

ASSAM POWER GENERATION CORPORATION LIMITED 100 THIRD FLOOR,BIJULEE BHAWAN,PALTAN BAZAR,GUWAHARI-01,ASSAM

PRE FEASIBILITY REPORT FOR 1X 660 MW SUPER CRITICAL MAR GHERITA THERMAL PROJECT, DISTRICT-TINSUKIA, ASSAM

SECTION – 10

EXECUTION AND PROJECT MANAGEMENT

10.1.0 CONSTRUCTION FACILITIES REQUIREMENT

The 1x 660 MW power stations is proposed to be located near Saliki Village at a distance around 2 km south-west of NH-38 in Margherita sub-divisional town of Tinsukia District of Assam. Adequate construction facilities such as office, stores, sheds etc. will be provided for the successful & timely implementation of the plant.

10.1.1 CONSTRUCTION POWER

The estimated construction power for construction of the plant is about 2000 KVA. The required construction power supply will be made available from existing substation at of APDCL. A DG set of adequate size will also be provided as standby arrangement for power supply at site for the construction phase of the power project.

10.1.2 TRANSPORT LIMITATIONS

Though the site of the proposed thermal power plant can be accessed by road, the connecting road between the site and NH-38 is a kachha road. This road is not suitable for heavy vehicles. The kachha road from NH-38 to the proposed thermal power plant site needs to be developed during project stage for heavy vehicle movement. The site is connected with DibrugarhTown by NH-37 via Tinsukia up to Makum and NH-38 from Makum upto Lekkhapani. Further this highway merges into NH-153 which goes upto Indian Border with Myanmar. The logistics will be further reviewed during detail engineering in line with the requirement of original equipment manufacturer.

10.1.3 WATER REQUIRED DURING CONSTRUCTION

The water required during construction is estimated at 200 Cu.m/day and will be met from suitable ground water source till water system is established alternatively.

Raw materials for the construction of the proposed station such as stone aggregate, conforming to IS-383 and sand free of silt meeting the requirements of IS-650 will be obtained from nearby area.

Cement will be available from Cement Plants in the State. Steel will be made available from the nearest steel stockyard.

10.2.0 Project Implementation Schedule

• The zero date has been taken as the day the main equipment packages viz. the steam generator, TG & their auxiliaries are ordered.

ASSAM POWER GENERATION CORPORATION LIMITED 101 THIRD FLOOR,BIJULEE BHAWAN,PALTAN BAZAR,GUWAHARI-01,ASSAM

PRE FEASIBILITY REPORT FOR 1X 660 MW SUPER CRITICAL MAR GHERITA THERMAL PROJECT, DISTRICT-TINSUKIA, ASSAM

• The Unit will be scheduled to 42 Months from the Date of Order

• The Erection, Testing & Commissioning of the units will be undertaken by a team of responsible, competent and efficient personnel to ensure that:

a) The units will be made ready for operation in the shortest possible time and in no case should the scheduled time is exceeded.

b) To reduce interest charges and unnecessarily large inventories will not be built up.

c) The plant once installed will have a high reliability and availability.

d) The timely design & construction of the main plant building housing the TG is important and will not be delayed on any account.

10.3.0 Project Manpower Requirements:

The recent development automation with advanced technology, the manpower would be quite limited. The estimated manpower requirement is indicated as below:

Man Power

Managerial / Executive (senior level) : 30

Engineers / Supervisors : 320

Operators : 120

Skilled Attendants : 80

Semi-skilled Attendants : 50

Total : 600

10.3.1 Basis of Manpower Estimates

In arriving at the manpower estimates, the following assumptions have made: The Manpower estimate has prepared with reference to the process and facilities Envisaged in the different shops. Whenever direct manning is involved the various positions have been identified on the basis of the layout, technology, equipment location and job affinity. Where a crew is required for a particular operation, the crew size has been determined taking into account the proposed facility and functions involved.

Keeping in view the extent of automation and computerization as envisaged in the project, Supervisors & skilled staff is not required much as presently deployed in old conventional plants. However, the proposed deployment of manpower, more or less matches with the standard norms which provide 0.4 men per MW for large

ASSAM POWER GENERATION CORPORATION LIMITED 102 THIRD FLOOR,BIJULEE BHAWAN,PALTAN BAZAR,GUWAHARI-01,ASSAM

PRE FEASIBILITY REPORT FOR 1X 660 MW SUPER CRITICAL MAR GHERITA THERMAL PROJECT, DISTRICT-TINSUKIA, ASSAM

Power Plant. It is assumed that the work force will, therefore, have the requisite skills to operate the equipment as well as make the minor repairs, and to set and adjust the equipment handled by them. They will also be responsible for proper up keeping of the equipment and the surrounding workplace. They will assist the maintenance personnel in maintaining the plant & equipment.

Provision of 20% of the manpower required per weekdays has been made to cover the weekly off, holiday, leave for departments /sections working seven- day week.

For departments /sections working 6 day week, a provision of 10% additional manpower has been made to cover holidays and leave.

Major maintenance of plant & equipment and Capital repair jobs will be outsourced. Only routine scheduled maintenance, running repairs and conditioning monitoring will be done departmentally. Also, operating staff of any equipment under maintenance will participate in maintenance along with the maintenance personnel.

10.3.2 Training

Depending on the level and experience of O & M staff, training programs will be designed and implemented by equipment manufacturer in association with O & M contractor and the owner. The covered includes the following:

• The Training at manufacturer’s works

• Training at operating plants in India and abroad where similar equipment are in operation.

• Maintenance training.

• Simulator training

• Skill up-gradation

• Workshops

10.3.3 Training Policy

An appropriate training policy would be adopted at the outset aiming to fulfill the main objectives of improving the organization efficiency & effectiveness as a whole and also to maintain a high technological status and develop an understanding of the importance of co-operation & teamwork.

ASSAM POWER GENERATION CORPORATION LIMITED 103 THIRD FLOOR,BIJULEE BHAWAN,PALTAN BAZAR,GUWAHARI-01,ASSAM

PRE FEASIBILITY REPORT FOR 1X 660 MW SUPER CRITICAL MAR GHERITA THERMAL PROJECT, DISTRICT-TINSUKIA, ASSAM

SECTION – 11

CLEAN DEVELOPMENT MECHANISM (CDM)

Clean Development Mechanism

The U.N. Framework Convention on Climate Change (UNFCCC) was adopted in June 1992 at the Earth Summit in Rio de Janeiro and the objective of the convention is to achieve stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system. The adjunct to the Convention, the Kyoto protocol, was hammered out in December 1997, setting individual targets for developed countries to reduce yearly emissions of Green House Gases (GHGs) to a minimum of 5 percent below their 1990 levels in the first commitment period,

2008-2012. India has ratified the Kyoto Protocol in 2002.

The Clean Development Mechanism (CDM), one of the flexible mechanisms under the Kyoto Protocol encourages development of Green house gas emission reduction projects in developing countries like India for achieving sustainable development and also earn carbon credits. The amount of carbon emission saved by such project is required to be certified by the CDM Executive Board. The certificate specifying carbon reduction in tones can be sold to developed countries which are signatories to the protocol. One tone of carbon di-oxide reduced through Clean Development Mechanism project in a developing country when certified by the CDM Executive Board becomes a tradable CER (Certified Emission Reduction).

To get a project registered under CDM, it has to run through an approval procedure, including the host country approval & validation, administered by the UNFCCC. The Ministry of Environment and Forests (MoEF), GoI is the Designated National Authority (DNA) in India for according hosts country approval.

APGCL intends to construct a new supercritical coal fired power project of capacity 1 X 660 MW MTTP with CDM intent, at Tinsukia district. Adopting Supercritical technology results in enhanced plant efficiency resulting in reduced coal

ASSAM POWER GENERATION CORPORATION LIMITED 104 THIRD FLOOR,BIJULEE BHAWAN,PALTAN BAZAR,GUWAHARI-01,ASSAM

PRE FEASIBILITY REPORT FOR 1X 660 MW SUPERCRITICAL MAR GHERITA THERMAL PROJECT, DISTRICT-TINSUKIA, ASSAM

SECTION – 12

PROJECT COST ESTIMATE

12.1.1 Project Cost:

The estimated project cost has been worked out on the following basis and assumptions:

• The project cost has been estimated based on the recently decided EPC tender of TANGEDCO for 660 MW (Super critical) Ennore thermal power station expansion project with a project cost of 3960 Crores ie Rs. 6.00 Crores per MW. Another 10% is added as it is a green field project.

• Fuel: Assam Coal is considered to be main fuel. The calorific value as coal is taken as 5500 kcal/kg . HFO / HSD shall be supporting and startup fuel.

• Electrical System: 400 kV switchyard for evacuation of power has been considered in the present cost estimate. Cost of transmission line has not been considered in the project cost.

• The project cost is inclusive of all taxes and duties.

• The Total Project cost is as below:

Total project cost: Rs. 4383.98 crores

Interest during construction : Rs. 763.54 crores

Total project Cost with IDC & contingency: Rs. 5278.20 crores

Total Project cost per MW : 8.00 crores

12.1.2 Financing Structure and Interest during Construction:

• It is proposed to finance the project through debt – equity ratio of 70:30.

Project Cost : 4383.98 Rs. Crores

Debt(%) : 70 % Debt (including IDC) : 3607.52 Rs. Crores Equity(%) : 30 %

ASSAM POWER GENERATION CORPORATION LIMITED 105 THIRD FLOOR,BIJULEE BHAWAN,PALTAN BAZAR,GUWAHARI-01,ASSAM

PRE FEASIBILITY REPORT FOR 1X 660 MW SUPERCRITICAL MAR GHERITA THERMAL PROJECT, DISTRICT-TINSUKIA, ASSAM

Equity : 1540.00 Rs. Crores Project Cost including IDC & C ontin gency : 5278.20 Rs. Crores Rate: of interest : 12.5 % • Time Schedule:

Commissioning of Unit – 1 (660 MW) :42 months from zero date

12.1.3 Estimation of Cost of Generation

The main objective is to estimate and analyze the capital cost of the project so as to be in a position to estimate the Cost of Generation.

The major assumptions are as follows:

i) Debt Equity Ratio : 70:30

ii) The Construction period for 2 X 660 MW : 42 months

iii) Interest on term loan has been considered as 12.5 % with 15 years of Repayment period after complete commissioning of the Plant.

iv) RoE is calculated on pre-tax basis at the base rate of 15.5%.

v) Working capital has been estimated based as follows:

a) Fuel Cost: 1.0 month

b) O&M Cost: 1.0 month

c) Margin Money: 10%

d) Rate of Interest: 12.5 %

e) Maintenance spares: 1% of the cost escalated @ 6% per year

vi) Auxiliary power consumption of the plant is 6% as per CERC guide line.

vii) Plant availability factor: 85% as per CERC guide line.

viii) O&M expenses have been considered as Rs. 16 lakh/MW with 5% escalation per year. )

ix) The plant gross heat rate has been considered as 2057 Kcal/Kwh as per

x) Depreciation has been considered at an average rate of 4.67% per year based on equipment- wise rates specified as per CERC guidelines. ASSAM POWER GENERATION CORPORATION LIMITED 106 THIRD FLOOR,BIJULEE BHAWAN,PALTAN BAZAR,GUWAHARI-01,ASSAM

PRE FEASIBILITY REPORT FOR 1X 660 MW SUPERCRITICAL MAR GHERITA THERMAL PROJECT, DISTRICT-TINSUKIA, ASSAM

a) Useful life of the Thermal po wer station = 25 years

b) Depreciation Rate for first 15 years = 4.67% c) Depreciation rate for remaining life = 2% xi) The calorific value of coal has been considered as 5500 Kcal/kg. xii) The cost of coal has been considered as Rs.4665 / MT and escalated @5% per year thereafter. The cost of support fuel oil is considered as Rs.50.000/- per KL. xiii) The oil consumption considered as @ 2 ml/KWh for the ml/KWh from 2nd year onwards. xiv) The annual plant load factor (PLF) has been taken as 85% once the system has stabilized after commissioning. (However, the plant loading most of the time will be 100%).

Based on the above assumptions, the first year tariff and the Levellized Tariff cost is given below:

Cost of generation @ 85% PLF on 1st year : Rs.3.401 / Unit

Levellised cost of generation @ 85% PLF : Rs. 3.220 / Unit

ASSAM POWER GENERATION CORPORATION LIMITED 107 THIRD FLOOR,BIJULEE BHAWAN,PALTAN BAZAR,GUWAHARI-01,ASSAM

PRE FEASIBI LITY REPORT FOR 1X 660 MW SUPER CRITICAL MAR GHERITA THERMAL PROJECT, DISTRICT -TINSUKIA, ASSAM

SECTION – 13

CONCLUSION

13.1.0 Advantages of supercritical technology

Supercritical technology delivers the most economical in i mprove efficiency and operating flexibility, achieve fuel cost savings, and reduce all emissions for each kWh of electricity generated, including CO2.

• Higher plant efficiency

• Less Fuel Consumption

• Less Infrastructure Investment for Fuel Transport / Storage and Ash Disposal

• Less Emission (CO2, SOx, NOx, Dust/Ash)

• Less Auxiliary Power Consumption

• Less Water Consumption (No need of continuous blows down in case of once - through boiler.)

• Lower operating costs

• Greater operating flexibility

13.1.1 Elevated Steam Conditions

As the steam conditions become higher, plant heat consumption becomes less. To this date, even 600/ 600 degree C (both superheater outlet and reheater outlet temperature are 600 degree C) is already in o peration outside India.

ASSAM POWER GENERATION CORPORATION LIMITED 108 THIRD FLOOR,BIJULEE BHAWAN,PALTAN BAZAR,GUWAHARI -01,ASSAM PRE FEASIBI LITY REPORT FOR 1X 660 MW SUPER CRITICAL MAR GHERITA THERMAL PROJECT, DISTRICT -TINSUKIA, ASSAM

Comparison of Typical Operation Modes

By adopting sliding pressure operation (more precisely, combined operation of constant and sliding pressure operation), plant efficiency becomes higher at partial load range.

• Higher HP turbine internal efficiency.

• Less BFP power consumption.

• Higher reheat steam temperature at partial load.

13.1.2 Plant Availability:

The plant availability is more than 90 %.

13.1.3 CDM Benefits

Sub Critical Boilers (500 MW sets) involves steam pressure of 170 bar and below and super heat / reheat temperature 5400C/5400C and super critical boilers would be designed with pressure of 257 ata and above and super heat/reheat temperature of 5680C / 5920C and even above due to t he invention of New materials.

Normally sub critical units having the Plant heat rate around 2300 -2400 Kcal / Kwh and super critical units having the plant heat rate are about 2100 Kcal / Kwh. By adopting Supercritical technology we have a ble to achieve 200 Kcal / Kwh which leads to less fuel consumption and less CO2 generation. This project can generate tradable carbon credits under CDM thus improving the financial viability of the project.

Table 13.1

Capacity MW 1 x 660 MW

Baseline emission factor 0.941 tCO2/MWh

Reduction in tonnes CO2 Emission for 1st 2395671.88

year

ASSAM POWER GENERATION CORPORATION LIMITED 109 THIRD FLOOR,BIJULEE BHAWAN,PALTAN BAZAR,GUWAHARI -01,ASSAM PRE FEASIBILITY REPORT FOR 1X 660 MW SUPER CRITICAL MAR GHERITA THERMAL PROJECT, DISTRICT-TINSUKIA, ASSAM

CDM Revenue for 1st year @ 2395671.88* Euro 12

1CER = Euro 12.0 (Dec’2010) =28748062.56 Euros

Reduction in tonnes CO2 Emission from 2nd 2994589.56 x 9 years

onwards upto 10th year 26951306.04

CDM Revenue for 2nd year to 10th year 26951306.04* Euro 12

1CER = Euro 12.0 (Dec’2010) = 323415672.5 Euros

Total CDM Revenue for 10 Years Rs 2289.07 crores

1 CER = Euro 11.89 (source: European Climate Exchange) CER Spot market price in Mumbai, India as on 17.12.2010:

CER = Rs. 702 per MT (source: Multi Commodity Exchange of India Ltd)

Hence, this project can generate tradable carbon credits under CDM thus improving the financial viability of the project.

13.1.4 The actual growth in industrial, agricultural and domestic demand will establish that there is an appreciable shortfall in the installed capacity, demand and energy availability as on date. This shortfall will continue even after the commissioning of the proposed power plants in various parts of the State. Added to the industrial demand the agriculture need as well as domestic consumption coupled with the improved standard of living of the population will be on the rise.

Based on the details of load forecast and assessment of likely addition of new generation capacity it is anticipated that Assam state would experience a power deficit of 10.7 % and energy deficit of 10.6 % in the year 2011-12.

This deficit in power and energy justifies the need for additional new power generation capacity. It is recommended to install a coal based thermal power plant with super critical technology of 1 x 660 MW at Margherita,Tinsukia District,Assam. The power plant of 1 x 660 MW capacity will be able to bridge the gap of power deficit.

ASSAM POWER GENERATION CORPORATION LIMITED 110 THIRD FLOOR,BIJULEE BHAWAN,PALTAN BAZAR,GUWAHARI-01,ASSAM

PRE FEASIBILITY REPORT FOR 1X 660 MW SUPER CRITICAL MAR GHERITA THERMAL PROJECT, DISTRICT-TINSUKIA, ASSAM

List of drawings

Sl no Drawing tit le 1 PLOTY PLAN 2 FLOW PROCESS 3 ELECTRICAL SINGLE LINE D IAGRAM 4 GENERAL ARRANGEMENT –ELEVATION 5 WATER BALANCE D IAGRAM

ASSAM POWER GENERATION CORPORATION LIMITED 111 THIRD FLOOR,BIJULEE BHAWAN,PALTAN BAZAR,GUWAHARI-01,ASSAM