NTPC LIMITED
PROJECT : KATWA STPP (2x660 MW)
PACKAGE NAME : EPC PACKAGE
The Brief scope of work for the subject EPC Package for KATWA STPP (2x660 MW) is as follows:
Design, Engineering, Manufacture, Supply, Construction, Erection, Testing & Commissioning works for the EPC Package for KATWA Super Thermal Power Project (2 x 660 MW), on the basis of single point responsibility, completely covering the following activities and services in respect of Steam Generator, Steam Turbine Generator and Electrostatic Precipitator, all Balance of Plant (BOP) systems (except for Make-up Water System, Ash Dyke & Township), all electrical systems including Switchyard, complete Control & Instrumentation and complete Civil, Structural and Architectural works & Railway Siding system and Solar PV Plants at roof-top covered under the specifications:
a) Basic Engineering of the plant including preparation of Plant Definition Manuals;
b) Detailed design of all the equipment and equipment system(s) including civil, structure steel & Architectural works included in bidder's scope.
c) Providing engineering drawings, equipment sizing & performance data, instruction manuals, as built drawings and other information;
d) Compliance with statutory requirements and obtaining clearances from statutory authorities, wherever required;
e) Complete manufacturing including shop testing/type testing;
f) The complete Civil, structural and architectural works including topographical survey, site leveling, construction water for plant area, labour colony, water supply and sanitation, infrastructure works including roads & drainage for plant, Effluent & sewage treatment facility for plant, plant boundary wall, main plant area structures and foundations including turbine building, bunker building, boiler structure, ESP structure, service building, compressor house, complete coal handling plant and Ash handling plant, chimney, pipe/cable galleries and pipe/cable trenches, duct banks, pedestals, cooling towers, balance of plant buildings including CW System, PT, DM and ETP buildings and structures, offsite structures and buildings, transformer yard structures, switchyard structures, fuel oil handling system and fire protection system structures and foundations, bridges and culverts for crossing of roads / Rail Tracks inside plant area, fencing / boundary wall around the land boundary, landscaping and other miscellaneous buildings and structures.
g) Packing and transportation from the manufacturer’s works to the site including logistic studies, insurance, customs clearance & port clearance, port charges, if any.
h) Receipt, storage, preservation, handling and conservation of equipment at the site;
i) Fabrication, pre-assembly, if any, erection, insurance, testing, commissioning and completion of facilities including putting into satisfactory operation all the equipment including successful completion of initial operation;
j) Performance and guarantee tests after successful completion of initial operation;
k) Supply of spares on FOR site basis;
Detailed scope of work has been specified in the bidding documents.
1.00.00 Steam Generator
1.01.00 Type
The Steam Generator shall be of single pass (Tower type) or two pass type using either spiral wall (inclined) or vertical plain / rifled type water wall tubing.
1.02.00 Other Features of Steam Generator Design
The Steam Generator shall be direct pulverized coal fired, top supported, single reheat, radiant, dry bottom, with balance draft furnace and shall be suitable for outdoor installation. The evaporator of Steam Generator shall be suitable for variable pressure operation from subcritical to supercritical pressure range.
1.03.00 Rating of Steam Generator(s)
Steam Generator shall be designed to cater to duty requirements at Boiler Maximum Continuous Rating (BMCR) specified below:
Capacity of Steam Generator and Rated Steam parameters: |
Steam Flow |
Temp. |
Pressure Kg/cm2(a) |
i) At super-heater outlet |
102% of the turbine VWO steam |
To achieve turbine throttle main steam temperature as indicated in clause 3.02.00. The steam temperature at Superheater outlet shall be atleast 3°C higher than the rated main steam temperature at HP turbine inlet. |
To achieve turbine throttle steam pressure as indicated in clause 3.02.00. the steam pressure at superheater outlet shall be atleast 9 kgCm2 higher than the rated main steam pressure at HP turbine inlet |
ii) At re-heater outlet |
- |
To achieve reheat steam temperature at Turbine Inlet as indicated in clause 3.02.00 of this Sub-section. The steam temperature at reheater outlet shall be atleast 3oC higher than the rated reheat steam temperature at IP turbine inlet. |
--- |
iii) Feed Water Temp. at Economizer Inlet |
|
To be optimized by the bidder but not less than 285oC |
|
1.04.00 Limiting Parameters for Steam Generator Design
The Steam Generator design shall comply with the following limiting parameters with `design coal’ firing, under stipulated ambient air condition i.e. 27 degree Celsius temperature and 60 % relative humidity:
Flue gas temperature at air-heater outlet - 125oC (minimum)
(Corrected) at 105% TMCR & 100 % TMCR load
1.05.00 Operating Requirements
1. |
Minimum load without oil support for flame stabilization |
40% BMCR |
2. |
Operation without HP heaters in service |
Steam generator shall also be designed for continuous operation with HP heaters out of operation. The steam generator heat output under HP heaters out condition shall be at least 100% BMCR heat output with HP heater in service. |
3. |
Steam generator control range |
The automatic control range of Steam Generator shall be from 50% TMCR to 100% BMCR. Under the above control range, the steam temperatures at SH & RH outlets shall be maintained at their rated values. |
4. |
Mode of Steam Generator Operation |
The Steam Generators shall be designed for variable pressure operation. Thermal design of Steam Generator and the selection of materials shall be suitable for variable pressure operational modes. |
5 |
Rate of loading / unloading
|
Minimum + 10% per minute
|
1.06.00 Coal/Ash data
The primary fuel for the main steam generator shall be coal. Light Diesel Oil (LDO) shall be used for start-up, coal flame stabilization and low load operation of the main Steam Generator(s).
2.00.00 Electrostatic Precipitator (ESP)
2.01.00 System Description:
The Electrostatic Precipitators shall be of outdoor type and installed on the cold end side of regenerative air preheaters. The flue gas shall be drawn from air preheater outlets of the balanced draft, pulverized coal fired Steam Generator and guided through adequately sized duct work into the specified number of independent gas streams of each ESP. Similarly, the flue gas after the Electrostatic Precipitators shall be led to the suction of the induced draft fans.
2.02.00 Service Conditions
The Steam Generators are designed to burn pulverised coal. LDO shall be used during startup and at low loads for warm up and flame stablisation of Steam Generator. The ESP shall be designed to remove fly ash particles (to meet the stipulated ESP emission levels) from the flue gas generated in the Steam Generator with pulverized coal firing.
3.00.00 Steam Turbine
The steam turbine generator unit shall conform to the following design and duty conditions:
Power Factor - |
0.85 (lagging) |
|
Terminal voltage - |
In the 18 to 27 KV range |
|
Frequency - |
50 Hz |
|
Speed - |
3000 rpm |
|
Short circuit ratio - |
Not less than 0.48 (without negative tolerance) |
5.00.00 Coal Handling Plant
Coal Handling Plant shall be designed based on specified Indian Coals.The plant shall also be designed for blending of imported coal and Indian coal in the proportion 30:70 by weight. Rated capacity of CHP shall be as specified in the technical Specification.
The design capacity of the conveyors shall be 110% of the rated capacity.
Wagon tippler shall be side-discharge type (Rotaside) and shall conform to RDSO G-33 Rev. 1.
6.00.00 Ash Handling Plant
Ash handling system consists of the following sub systems:
OR
Two alternatives for pneumatic conveying system are specified for conveying of fly ash in dry form from ESP hoppers upto buffer hoppers. i.e. vacuum conveying system or pressure conveying system
It shall consist of liquid ring vacuum pumps, material handling valves, cast iron and MS pipes, instrument air compressors etc.
OR
ii) Pressure Conveying System
It shall consist of screw compressors, air lock/pump tanks, ash intake & discharge valves, CI & MS pipes, instrument air compressors etc.
The dry fly ash from the buffer hoppers in each unit shall be transported to either silos for slurry disposal system or to storage silos. The user industries shall take the dry fly ash from storage silos either in closed tankers or in open tankers.
The dewatered bottom ash and the fly ash shall together be disposed off by high concentration slurry disposal (HCSD) system. In high concentration slurry disposal (HCSD), the bottom ash and fly ash in suitable proportions shall be mixed with water to form high concentration combined slurry. The slurry shall be pumped to the disposal area by means of positive displacement pumps.
7.00.00 CW Pumps
CW equipment & Systems shall be provided as per the scope of technical specifications.
8.00.00 Cooling Tower
The Cooling towers and associated equipment & systems shall be provided as per the scope of technical specification.
9.00.00 WATER TREATMENT SYSTEM
Water treatment system covers pre-treatment, chlorination, Liquid Effluent Treatment, De-mineralization system & condensate polishing system.
10.00.00 Electrical Systems
The electrical items shall cover following:
11.00.00 C & I Systems
The control system, called Distributed Digital Control Monitoring & Information system (DDCMIS) is envisaged to be procured under this package for control and operation of
Human Machine Interface & Plant Information System (HMIPIS) is based on Large Video Screen (LVS) displays supported by TFT monitor based Operator Work Stations (OWS). These devices through customized user-friendly displays, soft alarm facia and pop-up displays are used for giving fast pin-pointed faults/ status to the operator. Local ON/OFF operation of equipments is envisaged through Graphical Interface Unit (GIU). The total system is networked through a Station-Wide LAN for use of real time data of various plant areas by other users like maintenance, planning, efficiency enhancement groups etc.
The sequence of events recording & alarm annunciation are also implemented as a part of DDCMIS system. A GPS based master and slave clock system is to be provided for uniform and synchronized timing signals throughout the entire station.
The power supply for the control system is based on 24V DC provided through microprocessor based modular charger system and for the peripherals and other subsystem through 230V Single Phase UPS.
Main Equipment related instruments like Flame Monitoring system, Coal Bunker Level measurement system, gravimetric feeder control system, Acoustic Pyrometer, Acoustic Steam Leak detection system, Furnace and Flame viewing system, Turbine stress control / evaluation system, Turbine supervisory and diagnostic system etc are also procured through this package.
Field instruments like pressure, DP, flow & level transmitter, analyzers along with their process connection & piping as well as measurement systems like vibration monitoring system etc are also procured through this package.
A plant-wide CCTV system based on IP technology is included in this package for surveillance of plant equipment as an aid to the operation.
Apart from above, an on-line Steam & Water analysis system (SWAS), PA system, Operator control desks, panels, shielded twisted pair cables as well as optical fiber cables for system interconnection and all types of Instrumentation Cables are also included in this package.
12.00.00 Civil Works
The site for Plant and offsite areas comprises of layers of silty clay / clayey silt and sand layer at deeper depths. Pile foundation is envisaged for major structures. The steel structures shall be pre-fabricated in factory and shall have bolted field connections.
13.00.00 SOLAR P.V. Plants
Solar Photo-voltaic plants to be supplied under the package shall be grid-connected rooftop SPV plants including all auxiliaries. The SPV modules must conform to latest edition of IEC 61215 / IS 14286 for crystalline silicon Terrestrial PV Modules design qualification and type approval. In addition, the modules must also conform to IEC 61730 part 1 & Part 2 or equivalent IS for construction & testing requirements respectively.
14.00.00 LOCOMOTIVES
Co-Co diesel electric locomotive of specified numbers for the 1676 mm gauge having gross installed capacity of approximately 3100 HP WDG3A type each under UIC conditions, complete in all respects, duly painted at manufacturer’s works shall be supplied on FOR site basis, thereafter supervision of all other activities, such as handling, storing, cleaning, commissioning and testing at site, of the equipment shall be provided.