A

Practical Training

Taken

At

“Kota Super Thermal Power Station”

1

Submitted to the

Rajasthan Technical University, Kota

Training held from (1st June – 30th June, 2012)

Submitted To: - Submitted By:-

Mr. Mahesh Sharma Gaurav Panjwani

Head of Department B.Tech. (3rd year)

Roll no. 09/EPK/ME/015

MAHARISHI ARVIND COLLEGE OF ENGGINERING AND

TECHNOLOGY

KOTA, (RAJ) INDIA

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PREFACE

The rise in civilization is closely related to improvements in transportation and

requirement of energy that is not readily available in large quantities but is also readily

transportable. A very peculiar fact about electrical energy is that neither it is directly available in

nature nor it is directly used finally in this form, yet it is so widely produced and is the most

popular high grade energy.

The purpose behind training is to understand the difficult concepts in a better way

with gain of knowledge. Report starts with a brief introduction of KSTPS followed by

Generator, Turbine, switch gear, switch yard etc.

While writing the report and while I was on my training I was wondering

that science is as ever expanding field and the engineers working hard day and night and

make the life a gift for us.

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Acknowledgement

I express my sincere thanks to my project guide Mr. Sunil Madan Designation, Course

Coordinator, for guiding me right form the inception till the successful completion of the

summer training. I sincerely acknowledge him for extending their valuable guidance,

support for literature, critical reviews of project and the report and above all the moral

support he had provided to me with all stages of this report.

I would also like to thank the other supporting staff, for their help and cooperation

throughout my summer training.

I use this opportunity to express gratitude and debtness to Er. Mahesh Sharma Sir , HOD,

MECHANICAL DEPARTEMENT, MACET, Kota.

Gaurav Panjwani

(Name of the Student)

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Abstract

Kota is a rambling city that rests on the banks of the Chambal River and proudly testifies

the triumphs of the gallant Rajputs. The city's architectural wonders, manifested by the

majestic palaces and crenelated forts are a stunning sight to behold.

The large industrial powerhouses like the Kota Super Thermal Power Plant stand tall

in the city and beautifully complement the grandiose heritage edifices.  In order to bring

about changes that would escalate the prospects of growth and development in the power

sector and to enforce the Power Sector Reforms, the Government of Rajasthan set up the

Rajasthan Rajya Vidyut Utpadan Nigam Ltd. (RVUN) in accordance with the

promulgations of the Companies Act-1956. Established on 19th July, 2000 the committee

is a torchbearer of Rajashthan's power sector. Under its aegis, the Kota Super Thermal

Power Station has total installed capacity of 1045 Megawatts. The Kota Super Thermal

Power Station has added another feather to its already brimming cap after receiving the

Union Ministry's Golden Shield award for four consecutive years spanning from 2000-

2004. 

Kota Super Thermal Power Station has reached such dizzying heights of success that its

sixth unit was set up on 30th July, 2003. In this unit, maximum capacity on coal firing

was attained in less than 10 hours and the phenomenal completion of the project in less

than two years is a groundbreaking achievement for the nation. Besides the philanthropic

organization also has a social conscience. The organization plants nearly 3.5 lakhs

saplings every year, digs up dykes and water bodies and monitors the effusion of effluent

materials and ambient air quality in order to check the pollution level. 

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Index of Contents

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Serial No. Particulars Page No.

1. Indian Power Industry

2. Profile of thermal industry in

Rajasthan.

3. Introduction to Kota Super Thermal

Power Station.

5. History of thermal power plants.

6. General definition of thermal power

plant.

7. Operations in a thermal power station.

8. Main parts of thermal power station.

9. Other systems

10 Fly ash utilization

11. SWOT Analysis

12. Conclusion

13. References

List of Figures

FIG. NO. DESCRIPTION PAGE NO.

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Fig.1 Different views of KTPS

Fig.2 View of KTPS from Chambal river

Fig.3 Block Diagram of Thermal Power Station

Fig.4 Operations In Thermal Power Station

Fig.5 Main Parts Of Thermal Power station

Fig.6 Cooling towers

Fig.7 Crossflow and Counterflow cooling

towers design

Fig.8 Transmission lines

Fig.9 Diagram of an electrical system.

Fig.10 Modern Steam Turbine Generator.

Fig.11 A rotor of a modern steam turbine, used in a power plant

Fig.12 Diagram of a typical water-cooled surface condenser

Fig.13 A simple control valve

Fig.14 Different types of deaerator

Fig.15 A Rankine cycle with a two-stage steam turbine and a single feedwater heater.

Fig.16 marine-type water tube boiler-see the steam drum at the top and feed drum

Fig.17 General view of superheater

Fig.18 Components of a centrifugal fan

Fig.19 Different Types Of Reheaters

Fig.20 The flames resulting from combustion

Fig.21 Economiser at KTPS

Fig.22 Schematic diagram of air preheater (APH) location.

Fig.23 Flue gas stack at KTPS ,kota

List of Tables

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Table No. Description Page No.

Table 1 Present Installed capacity of Rajasthan

Rajya Vidyut Utpadan Nigam

Table 2 Kota Thermal Power Station installed

capacity

Table 3 Awards received by KTPS

List of Abbreviations

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1). KSTPS - Kota Super Thermal Power Station.

2). NTPC - National Thermal Power Corporation.

3). RVUN - Rajasthan Vidhut Utpadan Nigam.

4). Ltd. - Limited

5). (BUs) - Billion Units

6). (SEBs) - State Electricity Boards

7).TPS - Thermal power station

8).EMF - Electro-motive force

9). HRSG - High recovery steam generator

10). FBA - Furnace Bottom Ash

11). IBA - Incinerator bottom ash

12). ESP - Electrostatic precipitator 

13). APH - Air preheater 

14). TBCCW - Turbine Building Closed Cooling Water

15). RPD - Rotating-plate design

16). DFT - Deareating feed tank 

17). AC  - Alternating current 

18). RAPH - Regenerative air preheaters

19). HRSGs - Heat Recovery Steam Generators

20). SWOT - strength, weakness, opportunity, threat

Indian Power Industry

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Growth of Power Sector infrastructure in India since its Independence has been

noteworthy making India the third largest producer of electricity in Asia. Generating

capacity has grown manifold from 1,362 MW in 1947 to 141GW (as on 30.09.2004)...

India’s Total installed capacity of power sector has been 141 GW. This India’s 141GW

of total power is generated by its three different sectors, i.e., state sector, central sector

and private sector.

India has fifth largest generation capacity in the world. India’s transmission and

distribution network is of 6.6 million circuit km. This is considered to be third largest in

the world. As per above chart, thermal fuels like Coal, gas, oil constitute 64.6% of India’s

total installed capacity, followed by 24.7% from hydro power, 2.9% nuclear energy and

7.7% from other energy sources.

Industry Structure

Power sector structure in India has been very simple yet well defined. Majority of

Generation, Transmission and Distribution capacities are with either public sector

companies or with State Electricity Boards (SEBs). National thermal power corporation,

Nuclear Power Corporation, National Hydro Electric Power Corporation are the public

sector companies in India which are into power generation. TATA power, Reliance

Energy is domestic private players; Marubeni Corporation is international private

players in power sector. public sector is only power generation. Private sector

participation is increasing especially in Generation, transmission and Distribution.

Distribution licences for several cities are already with the private sector. Three large

ultra-mega power projects of 4000MW each have been recently awarded to the private

sector on the basis of global tenders.

Profile of Thermal Industry in Rajasthan

Present Installed capacity of Rajasthan Rajya Vidyut Utpadan Nigam is

3847.35 MW

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Power Station Capacity as on 31.03.09 Present Capacity

Suratgarh TPS 1500 MW 1500 MW

Kota STPS 1045 MW 1045 + 195 MW

Chhabra Super Thermal Power Station - 250 MW

Ramgarh Gas Power Plant 113.50MW 113.50MW

Mahi Hydel 140 MW 140 MW

MMH Schemes 23.85 MW 23.85 MW

Giral Lignite TPS 250 MW 250 MW

Dholpur CCPP 330 MW 330 MW

Total 3402.35 MW 3847 .35 MW

Rana Pratap Sagar Hydel PS (4X43 MW) 172 MW

Jawahar Sagar Hydel PS (3X33 MW) 99 MW

Total 271 MW

(Table 1)

Introduction to Kota Super Thermal Power Station

`

Kota Thermal Power Station is Rajasthan's First major coal power station. Presently it is in

operation with installed capacity of 1045MW.And one more unit of 250MW is slated for

commissioning in March 2009.

Stage Unit No. Capacity(MW) Synchronising Cost(Rs. Crore)

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Date

I 1 110 17.1.1983 143

2 110 13.7.1983

II 3 210 25.9.1988 480

4 210 1.5.1989

III 5 210 26.3.1994 480

IV 6 195MW 31.7.2003 635

V 7 195MW 30.5 2009 880

(Table 2)

 Excellent Performance

Kota Thermal Power Station of RVUN is reckoned one of the best, efficient and prestigious

power stations of the country. KSTPS has established a record of excellence and has earned

meritorious productivity awards from the Ministry of Power, Govt.of India during 1984, 1987,

1989, 1991& every year since 1992-93 onwards.

 

Planned maintenance period reduced to 7% Approx.

Expected Power generation during 2007-08 around 90%·

Man Power is only 1.4 per MW·

Ash Utilisation 80% (Dry fly ash 100%)

Environmental Profile

Adequate measures have been taken to control pollution and ensure atmospheric emission

within the prescribed limits of Environment (Protection) Act1986.

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180 meter high stack have been provided to release flue gases into the atmosphere at an

approx. velocity 25m/sec. so as to disperse the emitted particulate matter over a wide spread

area. Adequate water spraying arrangements have been provided at coal unloading, transfer

and conveying system to arrest and restrict Fugitive Emission.

Regular monitoring of Stack Emission,Ambient Air Quality and Trade Effluent is carried out

Year Million Units Generated

 Plant Load factor (%)

Award

1999-00 6314 84.44 Cash award of Rs.8.31.Lacs for productivity and Rs.6.19.Lacs each for saving in specific oil consumption for the years 1999 and 2000, Shields and Bronze medal.

2000-01 6437 86.60

Golden Shield award from Union Ministry of power

2001-02 6351 85.302002-03 6553 88.012003-04 6424 86.04

(Table 3)

(fig1). Different views of KSTPS

History of Thermal Power Plants.

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Reciprocating steam engines have been used for mechanical power sources since the 18th

Century, with notable improvements being made by James Watt. The very first

commercial central electrical generating stations in New York and London, in 1882, also

used reciprocating steam engines. As generator sizes increased, eventually turbines took

over due to higher efficiency and lower cost of construction. By the 1920s any central

station larger than a few thousand kilowatts would use a turbine prime mover.

(Fig.2) View of KTPS from Chambal River

Definition of Thermal Power Station

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A thermal power station is a power plant in which the prime mover is steam driven.

Water is heated, turns into steam and spins a steam turbine which either drives

an electrical generator or does some other work, like ship propulsion. After it passes

through the turbine, the steam is condensed in a condenser and recycled to where it was

heated; this is known as a Rankine cycle. The greatest variation in the design of thermal

power stations is due to the different fuel sources. Some prefer to use the term energy

center because such facilities convert forms of heat energy into electrical energy.

(Fig.3) Block Diagram of Thermal Power Station

Operations in Thermal Power Station

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Step wise operations in a thermal power plant are as follows:-

1).Coal is used as a fuel to boil the water.

2).Water is boiled to form pressurized steam.

3).Pressurised steam is the force that causes the turbine to rotate at a very high speed.

4).Low pressure steam after pushing through the turbine, it’s going into the condenser.

5).Condenser – the place where the steam is condensed back ti its liquid form .Then the

process is repeated.

(Fig 4.) Operations in Thermal Power Station

Main Parts of Thermal Power station

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1. Cooling tower 9. Steam Control valve17. Forced,induced

draught (draft) fan

2. Cooling water pump 10. Deaerator 18. Reheater

3. Transmission line (3-phase) 11. Feedwater heater19. Combustion air

intake

4. Step-up transformer (3-phase) 12. Coal hopper 20. Economiser

5. Electrical generator (3-phase) 13. Coal pulverizer 21. Air preheater

6. Low,intermediate,high pressure steam

turbine

14. Boiler & steam

drum22. Precipitator

7. Condensate pump 15. Bottom ash hopper 23. Flue gas stack

8. Surface condenser 16. superheater

(Fig. 5) Main Parts of Thermal Power station

1). Cooling Tower 

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Cooling towers are heat removal devices used to transfer process waste heat to

the atmosphere. Cooling towers may either use the evaporation of water to remove

process heat and cool the working fluid to near the wet-bulb air temperature or rely solely

on air to cool the working fluid to near the dry-bulb air temperature. Common

applications include cooling the circulating water used in oil refineries, chemical

plants, power stations and building cooling. The towers vary in size from small roof-top

units to very large hyperboloid structures (as in Image 1) that can be up to 200 metres tall

and 100 metres in diameter, or rectangular structures (as in Image 2) that can be over 40

metres tall and 80 metres long. Smaller towers are normally factory-built, while larger

ones are constructed on site.

(Fig. 6) cooling towers

Classification of cooling towers

- Crossflow

Crossflow is a design in which the air flow is directed perpendicular to the water flow

(see diagram below). Air flow enters one or more vertical faces of the cooling tower to

meet the fill material. Water flows (perpendicular to the air) through the fill by gravity.

The air continues through the fill and thus past the water flow into an open plenum area.

A distribution or hot water basin consisting of a deep pan with holes or nozzles in the

bottom is utilized in a crossflow tower. Gravity distributes the water through the nozzles

uniformly across the fill material.

- Counterflow

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In a counterflow design the air flow is directly opposite of the water flow (see diagram

below). Air flow first enters an open area beneath the fill media and is then drawn up

vertically. The water is sprayed through pressurized nozzles and flows downward through

the fill, opposite to the air flow.

(Fig 7.) Crossflow and Counterflow cooling towers design

iii). Cooling tower as a flue gas stack

At some modern power stations, equipped with flue gas purification like Kota Super

Thermal Power Station the cooling tower is used as a flue gas stack (industrial chimney).

At plants without flue gas purification, this causes problems with corrosion.

2). Cooling Water Pump

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In power plants, water cooling systems are typically used for removing heat

(cooling). These water cooling systems are, in turn, then cooled by the ultimate

cooling system river, lake, sea, or ocean water

These cooling water systems have separate subsystems, each with:  one or more

pumps for circulating fluid through the watercooling systems one heat exchanger

to transfer heat to the Ultimate water Cooling System an automatic valve to

regulate the heat removed from the Component Cooling system to the Ultimate

cooling system. There is usually a shared tank, called a surge tank, for the

redundant sub-systems is used as a makeup supply if there is not enough water in

the system, or to handle the surge (increase in level) if there is too much water in

the system.  Turbine Building Closed Cooling Water Systems 

The Turbine Building Closed Cooling Water (TBCCW) Systems cool heat exchangers

for:  

1. Feedwater Pump Seal Water

2. Condensate Pump Seal Water

3. Heater Drain Pump Seal Wate

3). Electric Power Transmission 

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Electric power transmission is the bulk transfer of electrical energy, a process in the

delivery of electricity to consumers. A power transmission network typically

Connects power plants to multiple substations near a populated area. The wiring from

substations to customers is referred to as electricity distribution, following the historic

business model separating the wholesale electricity transmission business

from distributors who deliver the electricity to the homes. [1] Electric power transmission

allows distant energy sources (such as hydroelectric power plants) to be connected to

consumers in population centers, and may allow exploitation of low-grade fuel resources

such as coal that would otherwise be too costly to transport to generating facilities.

(Fig 8) Transmission lines

Transmission lines;-

Usually transmission lines use three phase alternating current (AC). Single phase AC

current is sometimes used in a railway electrification system.High-voltage direct

current systems are used for long distance transmission, or some undersea cables, or for

connecting two different ac networks.

Electricity is transmitted at high voltages (110 kV or above) to reduce the energy lost in

transmission. Power is usually transmitted as alternating current through overhead power

lines. Underground power transmission is used only in densely populated areas because

of its higher cost of installation and maintenance when compared with overhead wires,

and the difficulty of voltage control on long cables.

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(Fig.9) Diagram of an electrical system.

i). Overhead transmission:-

Overhead conductors are not covered by insulation. The conductor material is nearly

always an aluminium alloy, made into several strands and possibly reinforced with steel

strands. Copper was sometimes used for overhead transmission but aluminium is lower in

weight for equivalent performance, and much lower in cost. Overhead conductors are a

commodity supplied by several companies worldwide. Improved conductor material and

shapes are regularly used to allow increased capacity and modernize transmission

circuits. Thicker wires would lead to a relatively small increase in capacity due to

the skin effect that causes most of the current to flow close to the surface of the wire.

ii). Underground transmission:-

Electric power can also be transmitted by underground power cables instead of overhead

power lines. They can assist the transmission of power across.Densely populated urban

Areas where land is unavailable or planning consent is difficult Rivers and other natural

obstacles Land with outstanding natural or environmental heritage Areas of significant or

prestigious infrastructural development Land whose value must be maintained for future

urban expansion and rural development

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4). Transformer 

A transformer is a device that transfers electrical energy from one circuit to another

through inductively coupled conductors—the transformer's coils. A varying current in the

first or primary winding creates a varying magnetic flux in the transformer's core, and

thus a varying magnetic field through the secondary winding. This varying magnetic

field induces a varying electromotive force (EMF) or "voltage" in the secondary winding.

This effect is called mutual induction.

Transformers can be classified in different ways:

By power capacity: from a fraction of a volt-ampere (VA) to over a thousand

MVA;

By frequency range: power-, audio-, or radio frequency;

By voltage class: from a few volts to hundreds of kilovolts;

By cooling type: air cooled, oil filled, fan cooled, or water cooled;

By application: such as power supply, impedance matching, output voltage and

current stabilizer, or circuit isolation;

By end purpose: distribution, rectifier, arc furnace, amplifier output;

By winding turns ratio: step-up, step-down, isolating (equal or near-equal ratio),

variable.

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5). Electrical Generator 

In electricity generation, an electrical generator is a device that converts mechanical

energy to electrical energy, generally using electromagnetic induction. The reverse

conversion of electrical energy into mechanical energy is done by a motor; motors and

generators have many similarities. A generator forces electric charges to move through an

external electrical circuit, but it does not create electricity or charge, which is already

present in the wire of its windings. It is somewhat analogous to a water pump, which

creates a flow of water but does not create the water inside. Thesource of mechanical

energy may be a reciprocating or turbine steam engine, water falling through a turbine or

waterwheel, an internal combustion engine, a wind turbine, a hand crank, compressed

air or any other source of mechanical energy.

(Fig.10) Steam Turbine Generator.

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6). Steam Turbine 

A steam turbine is a mechanical device that extracts thermal energy from

pressurized steam, and converts it into rotary motion.

It has almost completely replaced the reciprocating piston steam engine(invented

by Thomas Newcomen and greatly improved by James Watt) primarily because of its

greater thermal efficiency and higher power-to-weight ratio. Because the turbine

generates rotary motion, it is particularly suited to be used to drive an electrical generator

- about 80% of all electricity generation in the world is by use of steam turbines. The

steam turbine is a form of heat engine that derives much of its improvement

inthermodynamic efficiency through the use of multiple stages in the expansion of the

steam, which results in a closer approach to the idealreversible process.

(Fig.11) A rotor of a modern steam turbine, used in a power plant

Types of turbines

a). Impulse turbines

An impulse turbine has fixed nozzles that orient the steam flow into high speed jets.

These jets contain significant kinetic energy, which the rotor blades, shaped like buckets,

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convert into shaft rotation as the steam jet changes direction. A pressure drop occurs

across only the stationary blades, with a net increase in steam velocity across the stage.

As the steam flows through the nozzle its pressure falls from inlet pressure to the exit

pressure (atmospheric pressure, or more usually, the condenser vacuum). Due to this

higher ratio of expansion of steam in the nozzle the steam leaves the nozzle with a very

high velocity. The steam leaving the moving blades is a large portion of the maximum

velocity of the steam when leaving the nozzle. The loss of energy due to this higher exit

velocity is commonly called the "carry over velocity”.

b). Reaction turbines

In the reaction turbine, the rotor blades themselves are arranged to form convergent

nozzles. This type of turbine makes use of the reaction force produced as the steam

accelerates through the nozzles formed by the rotor. Steam is directed onto the rotor by

the fixed vanes of the stator. It leaves the stator as a jet that fills the entire circumference

of the rotor. The steam then changes direction and increases its speed relative to the speed

of the blades. A pressure drop occurs across both the stator and the rotor, with steam

accelerating through the stator and decelerating through the rotor, with no net change in

steam velocity across the stage but with a decrease in both pressure and temperature,

reflecting the work performed in the driving of the rotor.

Types

Steam turbines are made in a variety of sizes ranging from small 1 hp (0.75 kW) units

(rare) used as mechanical drives for pumps, compressors and other shaft driven

equipment, to 2,000,000 hp (1,500,000 kW) turbines used to generate electricity. There

are several classifications for modern steam turbines.

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7). Condensate Pump

A condensate pump is a specific type of pump used to pump the condensate (water)

produced in an HVAC (heating or cooling),refrigeration, condensing boiler furnace

or steam system. They may be used to pump the condensate produced from latent water

vapor in any of the following gas mixtures:

- conditioned (cooled or heated) building air

- refrigerated air in cooling and freezing systems

- Steam in heat exchangers and radiators

- the exhaust stream of very-high-efficiency furnaces

Construction and operation

Condensate pumps as used in hydro systems are usually electrically powered centrifugal

pumps. As used in homes and individual heat exchangers, they are often small and rated

at a fraction of a horsepower, but in commercial applications they range in size up to

many horsepower and the electric motor are usually separated from the pump body by

some form of mechanical coupling. Large industrial pumps may also serve as the

feedwater pump for returning the condensate under pressure to a boiler.

Condensate pumps usually run intermittently and have a tank in which condensate can

accumulate. Eventually, the accumulating liquid raises afloat switch energizing the pump.

The pump then runs until the level of liquid in the tank is substantially lowered. Some

pumps contain a two-stage switch. As liquid rises to the trigger point of the first stage, the

pump is activated. If the liquid continues to rise (perhaps because the pump has failed or

its discharge is blocked), the second stage will be triggered. This stage may switch off the

HVAC equipment (preventing the production of further condensate); trigger an alarm, or

both.

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8). Surface Condenser

i). Purpose

In thermal power plants, the primary purpose of a surface condenser is to condense the

exhaust steam from a steam turbine to obtain maximum efficiency and also to convert the

turbine exhaust steam into pure water (referred to as steam condensate) so that it may be

reused in the steam generator or boiler as boiler feed water.

ii). Diagram of water-cooled surface condenser

(Fig 12) Diagram of a typical water-cooled surface condenser

The surface condenser is a shell and tube heat exchanger in which cooling water is

circulated through the tubes. The exhaust steam from the low pressure turbine enters the

shell where it is cooled and converted to condensate (water) by flowing over the tubes.

Such condensers use steam ejectors or rotary motor-driven exhausters for continuous

removal of air and gases from the steam side to maintain vacuum. For best efficiency, the

temperature in the condenser must be kept as low as practical in order to achieve the

lowest possible pressure in the condensing steam. Since the condenser temperature can

almost always be kept significantly below 100 oC where the vapor pressure of water is

much less than atmospheric pressure, the condenser generally works under vacuum.

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9). Steam Control Valves

Control valves are valves used to control conditions such as flow, pressure, temperature,

and liquid level by fully or partially opening or closing in response to signals received

from controllers that compare a "set point" to a "process variable" whose value is

provided by sensors that monitor changes in such conditions. [1]

The opening or closing of control valves is done by means of electrical,

hydraulic or pneumatic systems. Petitioners are used to control the opening or closing of

the actuator based on Electric, or Pneumatic Signals. These control signals, traditionally

based on 3-15psi (0.2-1.0bar), more common now are 4-20mA signals for industry, 0-

10V for HVAC systems, & the introduction of "Smart" systems, HART, Field bus

Foundation, & Prefabs being the more common protocols.

(Fig 13) A simple control valve

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10). Deaerator

A Deaerator is a device that is widely used for the removal of air and other

dissolved gases from the feedwater to steam-generating boilers. In particular,

dissolved oxygen in boiler feed waters will cause serious corrosion damage in steam

systems by attaching to the walls of metal piping and other metallic equipment and

forming oxides (rust). It also combines with any dissolved carbon dioxide to

form carbonic acid that causes further corrosion. Most Deaerator is designed to remove

oxygen down to levels of 7 ppb by weight (0.0005 cm³/L) or less.

There are two basic types of deaerators, the tray-type and the spray-type:

The tray-type (also called the cascade-type) includes a vertical domed deaeration section

mounted on top of a horizontal cylindrical vessel which serves as the deaerated boiler

feedwater storage tank.

The spray-type consists only of a horizontal (or vertical) cylindrical vessel which serves

as both the deaeration section and the boiler feedwater storage tank.

a). Tray-type deaerator b). Spray-type deaerator

(Fig 14) Different types of deaerator

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11). Feedwater Heater

(Fig. 15) A Rankine cycle with a two-stage steam turbine and a single feedwater

heater.

A feedwater heater is a power plant component used to pre-heat water delivered to

a steam generating boiler.  Preheating the feedwater reduces the irreversibility’s involved

in steam generation and therefore improves the thermodynamic efficiency of the

system. [4] This reduces plant operating costs and also helps to avoid thermal shock to the

boiler metal when the feedwater is introduced back into the steam cycle.

In a steam power plant (usually modeled as a modified Rankine cycle), feedwater heaters

allow the feedwater to be brought up to the saturation temperature very gradually. This

minimizes the inevitable irreversibility’s associated with heat transfer to the working

32

fluid (water). See the article on the Second Law of Thermodynamics for a further

discussion of such irreversibility’s.

i). Cycle discussion and explanation

It should be noted that the energy used to heat the feedwater is usually derived from

steam extracted between the stages of the steam turbine. Therefore, the steam that would

be used to perform expansion work in the turbine (and therefore generate power) is not

utilized for that purpose. The percentage of the total cycle steam mass flow used for the

feedwater heater is termed the extraction fraction [4] and must be carefully optimized for

maximum power plant thermal efficiency since increasing this fraction causes a decrease

in turbine power output.

Feedwater heaters can also be open and closed heat exchangers. An open feedwater

heater is merely a direct-contact heat exchanger in which extracted steam is allowed to

mix with the feedwater. This kind of heater will normally require a feed pump at both the

feed inlet and outlet since the pressure in the heater is between the boiler pressure and

the condenser pressure. A deaerator is a special case of the open feedwater heater which

is specifically designed to remove non-condensable gases from the feedwater.

Closed feedwater heaters are typically exchangers where the feedwater passes throughout

the tubes and is heated by turbine extraction steam. These do not require separate pumps

before and after the heater to boost the feedwater to the pressure of the extracted steam as

with an open heater.

Feedwater heaters are used in both fossil- and nuclear-fueled power plants. Smaller

versions have also been installed on locomotives, portable and stationary engines.

An economiser serves a similar purpose to a feedwater heater, but is technically different.

Instead of using actual cycle steam for heating, it uses the lowest-temperature flue

gas from the furnace (and therefore does not apply to nuclear plants) to heat the water

before it enters the boiler proper. This allows for the heat transfer between the furnace

and the feedwater occurring across a smaller average temperature gradient (for the steam

generator as a whole). System efficiency is therefore further increased when viewed with

respect to actual energy content of the fuel.

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12). Coal Hopper

Coal is a readily combustible black or brownish-black sedimentary rock normally

occurring in rock strata in layers or veins called coal beds. The harder forms, such

as anthracite coal, can be regarded as metamorphic rock because of later exposure to

elevated temperature and pressure. It is composed primarily ofcarbon along with variable

quantities of other elements, chiefly sulfur, hydrogen, oxygen and nitrogen.

Peat, considered to be a precursor of coal, has industrial importance as a fuel in

some regions, for example, Ireland and Finland.

Lignite, also referred to as brown coal, is the lowest rank of coal and used almost

exclusively as fuel for electric power generation. Jet is a compact form of lignite

that is sometimes polished and has been used as an ornamental stone since

the Iron Age.

Sub-bituminous coal, whose properties range from those of lignite to those of

bituminous coal are used primarily as fuel for steam-electric power generation.

Additionally, it is an important source of light aromatic hydrocarbons for

the chemical synthesis industry.

Bituminous coal, dense mineral, black but sometimes dark brown, often with

well-defined bands of bright and dull material, used primarily as fuel in steam-

electric power generation, with substantial quantities also used for heat and power

applications in manufacturing and to make coke.

Anthracite, the highest rank; a harder, glossy, black coal used primarily for

residential and commercial space heating. It may be divided further into

metamorphically altered bituminous coal and petrified oil, as from the deposits in

Pennsylvania.

Graphite, technically the highest rank, but difficult to ignite and is not so

commonly used as fuel: it is mostly used in pencils and, when powdered, as

a lubricant

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Coal is primarily used as a solid fuel to produce electricity and heat through combustion.

World coal consumption was about 6,743,786,000 short tons in 2006 and is expected to

increase 48% to 9.98 billion short tons by 2030. China produced 2.38 billion tons in

2006. India produced about 447.3 million tons in 2006. 68.7% of China's electricity

comes from coal. The USA consumes about 14% of the world total, using 90% of it for

generation of electricity. 

Fuel processing

Coal is prepared for use by crushing the rough coal to pieces less than 2 inches (5 cm) in

size. The coal is then transported from the storage yard to in-plant storage silos by

rubberized conveyor belts at rates up to 4,000 tons/hour.

In plants that burn pulverized coal, silos feed coal pulverizers (coal mills) that take the

larger 2-inch pieces, grind them to the consistency offace powder, sort them, and mix

them with primary combustion air which transports the coal to the furnace and preheats

the coal to drive off excess moisture content. A 500 MWe plant will have six such

pulverizers, five of which can supply coal to the furnace at 250 tons per hour under full

load.

In plants that do not burn pulverized coal, the larger 2-inch pieces may be directly fed

into the silos which then feed the cyclone burners, a specific kind of combustor that can

efficiently burn larger pieces of fuel.

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13). Coal Pulverizer

A pulverizer is a mechanical device for the grinding of many different types of

materials. For example, they are used to pulverize coal for combustion in the steam-

generating furnaces of fossil fuel power plants.

Types of pulverizers

- Ball and tube mills

A ball mill is a pulverizer that consists of a horizontal rotating cylinder, up to three

diameters in length, containing a charge of tumbling or cascading steel balls, pebbles, or

rods.

A tube mill is a revolving cylinder of up to five diameters in length used for fine

pulverization of ore, rock, and other such materials; the material, mixed with water, is fed

into the chamber from one end, and passes out the other end as slime.

- Ring and ball mill

This type of mill consists of two rings separated by a series of large balls. The lower ring

rotates, while the upper ring presses down on the balls via a set of spring and adjuster

assemblies. The material to be pulverized is introduced into the center or side of the

pulverizer (depending on the design) and is ground as the lower ring rotates causing the

balls to orbit between the upper and lower rings.

- Demolition pulverizer

An attachment fitted to an excavator. Commonly used in demolition work to break up

large pieces of concrete.

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14). Boiler and Boiler Steam Drum

A boiler is an enclosed vessel that provides a means for combustion heat to be

transferred into water until it becomes heated water or steam. The hot water or steam

under pressure is then usable for transferring the heat to a process. Water is a useful and

cheap medium for transferring heat to a process. When water is boiled into steam its

volume increases about 1,600 times, producing a force that is almost as explosive as

gunpowder. This causes the boiler to be extremely dangerous equipment that must be

treated with utmost care.

Boiler operation

The boiler is a rectangular furnace about 50 feet (15 m) on a side and 130 feet (40 m) tall.

Its walls are made of a web of high pressure steel tubes about 2.3 inches (60 mm) in

diameter.

Pulverized coal is air-blown into the furnace from fuel nozzles at the four corners and it

rapidly burns, forming a large fireball at the center. The thermal radiation of the fireball

heats the water that circulates through the boiler tubes near the boiler perimeter. The

water circulation rate in the boiler is three to four times the throughput and is typically

driven by pumps. As the water in the boiler circulates it absorbs heat and changes into

steam at 700 °F (370 °C) and 3,200 psi (22 MPa). It is separated from the water inside a

drum at the top of the furnace. The saturated steam is introduced into superheat pendant

tubes that hang in the hottest part of the combustion gases as they exit the furnace. Here

the steam is superheated to 1,000 °F (540 °C) to prepare it for the turbine.

Plants that use gas turbines to heat the water for conversion into steam use boilers known

as HRSGs, Heat Recovery Steam Generators. The exhaust heat from the gas turbines is

used to make superheated steam that is then used in a conventional water-steam

generation cycle, as described in Gas turbine combined-cycle plants section below

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The water supplied to the boiler that is converted into steam is called feed water.

There are virtually infinite numbers of boiler designs but generally they fit into

one of two categories:

1. Fire tube or "fire in tube" boilers; contain long steel tubes through which

the hot gasses from a furnace pass and around which the water to be

converted to steam circulates. Fire tube boilers, typically have a lower

initial cost, are more fuel efficient and easier to operate, but they are

limited generally to capacities of 25 tons/hr and pressures of 17.5

Kg/cm

2. Water tube or "water in tube" boilers in which the conditions are

reversed with the water passing through the tubes and the hot gasses

passing outside the tubes. These boilers can be of single- or multipledrum

type. These boilers can be built to any steam capacities and

pressures, and have higher efficiencies than fire tube boilers.

Steam drums are a regular feature of water tube boilers. It is a reservoir of water/steam

at the top end of the water tubes in the water-tube boiler. They store the steam generated

in the water tubes and act as a phase separator. The difference in densities between hot

and cold water helps in the accumulation of the "hotter"-water/and saturated-steam into

the steam-drum.

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(Fig 16) marine-type water tube boiler-see the steam drum at the top and feed drum

15). Bottom Ash Hopper

Bottom ash refers to the non-combustible constituents of coal with traces of

combustibles embedded in forming clinkers and sticking to hot side walls of a coal-

burning furnace during its operation. The portion of the ash that escapes up the chimney

or stack is, however, referred to as fly ash. The clinkers fall by themselves into the water

or sometimes by poking manually, and get cooled.

The clinker lumps get crushed to small sizes by clinker grinders mounted under water and

fall down into a trough from where a water ejector takes them out to a sump. From there

it is pumped out by suitable rotary pumps to dumping yard far away. In another

arrangement a continuous link chain scrapes out the clinkers from under water and feeds

them to clinker grinders outside the bottom ash hopper.

Bottom ash may be used as an aggregate in road construction and concrete, where it is

known as furnace bottom ash (FBA), to distinguish it from incinerator bottom ash (IBA),

the non-combustible elements remaining after incineration. It was also used in the

making of the concrete blocks used to construct many high-rise flats in London in the

1960s

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16). Superheater

A super heater is a device in a steam engine that heats the steam generated by

the boiler again, increasing its thermal energy and decreasing the likelihood

that it will condense inside the engine. Super heaters increase the efficiency of

the steam engine, and were widely adopted. Steam which has been

superheated is logically known as superheated steam; non-superheated steam

is called saturated steam or wet steam.

Super heaters were applied to steam locomotives in quantity from the early

20th century, to most steam vehicles, and to stationary steam engines

including power stations.

(Fig. 17) General view of superheater

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17). Centrifugal Fan

A centrifugal fan (also squirrel-cage fan, as it looks like a hamster wheel) is a

mechanical device for moving air or gases. It has a fan wheel composed of a number of

fan blades, or ribs, mounted around a hub. As shown in Figure 1, the hub turns on

a driveshaft that passes through the fan housing. The gas enters from the side of the

fan wheel, turns 90 degrees and accelerates due to centrifugal force as it flows over the

fan blades and exits the fan housing. [1]

(Fig 18): Components of a centrifugal fan

Centrifugal fans can generate pressure rises in the gas stream. Accordingly, they are well-

suited for industrial processes and air pollution control systems. They are also common in

central heating/cooling systems.

a) Fan components

The major components of a typical centrifugal fan include the fan wheel, fan housing,

drive mechanism, and inlet and/or outlet dampers.

b). Fan dampers

Fan dampers are used to control gas flow into and out of the centrifugal fan. They may be

installed on the inlet side or on the outlet side of the fan, or both. Dampers on the outlet

side impose a flow resistance that is used to control gas flow. Dampers on the inlet side

are designed to control gas flow and to change how the gas enters the fan wheel.Inlet

dampers reduce fan energy usage due to their ability to affect the airflow pattern into the

fan. 

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18). Reheater

Power plant furnaces may have a reheater section containing tubes heated by hot flue

gases outside the tubes. Exhaust steam from the high pressure turbine is rerouted to go

inside the reheater tubes to pickup more energy to go drive intermediate or lower pressure

turbines.

(Fig 19). Different Types of Reheaters

19). Combustion 

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Combustion or burning is a complex sequence of exothermic chemical reactions

between a fuel (usually hydrocarbon) and an oxidant accompanied by the production

of heat or both heat and light in the form of either a glow or flames, appearance of light

flickering.

(Fig. 20)The flames resulting from combustion

Direct combustion by atmospheric oxygen is a reaction mediated

by radical intermediates. The conditions for radical production are naturally produced

by thermal runaway, where the heat generated by combustion is necessary to maintain the

high temperature necessary for radical production.

In a complete combustion reaction, a compound reacts with an oxidizing element, such

as oxygen or fluorine, and the products are compounds of each element in the fuel with

the oxidizing element. For example:

CH4 + 2O2 → CO2 + 2H2O

CH2S + 6F2 → CF4 + 2HF + SF6

A simpler example can be seen in the combustion of hydrogen and oxygen, which is a

commonly used reaction in rocket engines:

2H2 + O2 → 2H2O (g) + heat

The result is water vapor.

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In the large majority of real-world uses of combustion, air is the source of oxygen (O2).

In air, each kg (lab) of oxygen is mixed with approximately 3.76 kg (lbm) of nitrogen.

The resultant flue gas from the combustion will contain nitrogen:

CH4 + 2O2 + 7.52N2 → CO2 + 2H2O + 7.52N2 + heat

When air is the source of the oxygen, nitrogen is by far the largest part of the resultant

flue gas.

In reality, combustion processes are never perfect or complete. In flue gases from

combustion of carbon (as in coal combustion) or carbon compounds (as in combustion

of hydrocarbons, wood etc.) both unburned carbon (as soot) and carbon compounds

(CO and others) will be present. Also, when air is the oxidant, some nitrogen can be

oxidized to various nitrogen oxides (NOx).

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20). Economizer

Economizers, or in British English economisers, are mechanical devices intended to

reduce energy consumption, or to perform another useful function like preheating a fluid.

The term economizer is used for other purposes as well. Boiler, powerplant, and heating,

ventilating, and air-conditioning (HVAC) uses are discussed in this article. In simple

terms, an economizer is a heat exchanger.

i). Powerplant

Economizers are commonly used as part of a heat recovery steam generator in

a combined cycle power plant. In an HRSG, water passes through an economizer, then

a boiler and then a superheater. The economizer also prevents flooding of the boiler with

liquid water that is too cold to be boiled given the flow rates and design of the boiler.

A common application of economizers in steam powerplant is to capture the waste heat

from boiler stack gases (flue gas) and transfer it to the boiler feedwater. This raises the

temperature of the boiler feedwater thus lowering the needed energy input, in turn

reducing the firing rates to accomplish the rated boiler output. Economizers lower stack

temperatures which may cause condensation of acidic combustion gases and serious

equipment corrosion damage if care is not taken in their design and material selection.

(Fig 21): Economizer at KSTPS

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21). Air Preheater

An air preheater (APH) is a general term to describe any device designed to

heat air before another process (for example, combustion in a boiler) with the primary

objective of increasing the thermal efficiency of the process. They may be used alone or

to replace a recuperative heat system or to replace a steam coil.

In particular, this article describes the combustion air preheaters used in

large boilers found in thermal power stations producing power from e.g. fossil

fuels, biomasses or waste.

(Fig. 22) Schematic diagram of air preheater (APH) location.

The purpose of the air preheater is to recover the heat from the boiler flue gas which

increases the thermal efficiency of the boiler by reducing the useful heat lost in the flue

gas. As a consequence, the flue gases are also sent to the flue gas stack (or chimney) at a

lower temperature, allowing simplified design of the ducting and the flue gas stack. It

also allows control over the temperature of gases leaving the stack (to meet emissions

regulations, for example).

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22). Electrostatic Precipitator

An electrostatic precipitator (ESP), or electrostatic air cleaner is particulate collection

device that removes particles from a flowing gas (such as air) using the force of an

induced electrostatic charge. Electrostatic precipitators are highly

efficient filtration devices that minimally impede the flow of gases through the device,

and can easily remove fine particulate matter such as dust and smoke from the air

stream. [1] . In contrast to wet scrubbers which apply energy directly to the flowing fluid

medium, an ESP applies energy only to the particulate matter being collected and

therefore is very efficient in its consumption of energy (in the form of electricity).

i). Modern industrial electrostatic precipitators

ESOPs continue to be excellent devices for control of many industrial particulate

emissions, including smoke from electricity-generating utilities (coal and oil fired), salt

cake collection from black liquor boilers in pulp mills, and catalyst collection from

fluidized bed catalytic cracker units in oil refineries to name a few. These devices treat

gas volumes from several hundred thousand ACFM to 2.5 million ACFM (1,180 m³/s) in

the largest coal-fired boiler applications. For a coal-fired boiler the collection is usually

performed downstream of the air preheater at about 320 dig’s which provides optimal

resistively of the coal-ash particles..

The original parallel plate-weighted wire design (described above) has evolved as more

efficient (and robust) discharge electrode designs were developed, today focusing on

rigid (pipe-frame) discharge electrodes to which many sharpened spikes are attached

(barbed wire), maximizing corona production. Modern controls, such as an automatic

voltage control, minimize sparking and prevent arcing (sparks are quenched within 1/2

cycle of the TR set), avoiding damage to the components.

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48

23). Flue gas stack

A flue gas stack is a type of chimney, a vertical pipe, channel or similar structure

through which combustion product gases called flue gases are exhausted to the outside

air. Flue gases are produced when coal, oil,natural gas, wood or any other fuel

is combusted in an industrial furnace, apower plant's steam-generating boiler, or other

large combustion device. Flue gas is usually composed of carbon dioxide (CO2) and

water vapor as well as nitrogen and excess oxygen remaining from the intake combustion

air. It also contains a small percentage of pollutants such as particulate matter, carbon

monoxide, nitrogen oxides and sulfur oxides. The flue gas stacks are often quite tall, up

to 400 meters (1300 feet) or more, so as to disperse the exhaust pollutants over a greater

area and thereby reduce theconcentration of the pollutants to the levels required by

governmental environmental policy and environmental regulation.

(Fig. 23)

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When the flue gases are exhausted from stoves, ovens, fireplaces, or other small

sources within residential abodes, restaurants, hotels, or other public buildings

and small commercial enterprises, their flue gas stacks are referred to as

chimneys.

i).Stack design

Designing chimneys and stacks to provide the correct amount of natural draft involves a

great many factors such as:

1. The height and diameter of the stack.

2. The desired amount of excess combustion air needed to assure complete

combustion.

3. The temperature of the flue gases leaving the combustion zone.

4. The composition of the combustion flue gas, which determines the flue

gas density.

5. The frictional resistance to the flow of the flue gases through the chimney or

stack, which will vary with the materials used to construct the chimney or stack.

6. The heat loss from the flue gases as they flow through the chimney or stack.

7. The local atmospheric pressure of the ambient air, which is determined by the

local elevation above sea level.

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Other Systems

(1). Monitoring and alarm system

Most of the power plant operational controls are automatic. However, at times, manual

intervention may be required. Thus, the plant is provided with monitors and alarm

systems that alert the plant operators when certain operating parameters are seriously

deviating from their normal range.

(2). Battery supplied emergency lighting and communication

A central battery system consisting of lead acid cell units is provided to supply

emergency electric power, when needed, to essential items such as the power plant's

control systems, communication systems, turbine lube oil pumps, and emergency

lighting. This is essential for a safe, damage-free shutdown of the units in an emergency

situation.

(3). Transport of coal fuel to site and to storage

Most thermal stations use coal as the main fuel. Raw coal is transported from coal

mines to a power station site by trucks, barges, bulk cargo ships or railway cars.

Generally, when shipped by railways, the coal cars are sent as a full train of cars. The

coal received at site may be of different sizes. The railway cars are unloaded at site by

rotary dumpers or side tilt dumpers to tip over onto conveyor belts below. The coal is

generally conveyed to crushers which crush the coal to about ¾ inch (6 mm) size. The

crushed coal is then sent by belt conveyors to a storage pile. Normally, the crushed coal is

compacted by bulldozers, as compacting of highly volatile coal avoids spontaneous

ignition.

The crushed coal is conveyed from the storage pile to silos or hoppers at the boilers by

another belt conveyor system.

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Fly Ash Utilization

FLY ASH UTILIZATION AT KSTPS :-

• Concerted efforts have been made towards encouraging entrepreneurs for

utilizing the ash generated at Kota Thermal Power Station. 100% fly ash

utilization is expected upto March, 2009. The ash is being provided free of

cost to various Cement Industries and brick kiln owners and other

Industrialists. Pond Ash which was stored during earlier years has also

been utilized in road works. The ash utilization at Kota TPS is highest in the

Country.

• For achieving 100% Dry Fly Ash utilization KTPS has signed agreements

with Cement manufacturing companies with dedicated unit allocations. The

complete Dry Fly Ash evacuation system from each unit in 2 phases i.e. from

ESP to intermediate silo to main supplying silo near KTPS boundary has

been erected, tested, commissioned and operated by the respective Cement

companies at their own cost.

• KOTA THERMAL POWER STATION ACHIEVED 98.48% DRY FLY ASH

UTILIZATION DURING 2007-08

DRY FLY ASH UTILIZATION- ADVANTAGES

1. Minimum land requirement for ash storage.

2. Minimum water requirement for conveying of ash.

3. High ash storage density.

4. ECO friendly – less airborne / water pollution.

5. Reduction in Auxiliary Power Consumption

6.100% fly ash utilization prospects.

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SWOT Analysis

"SWOT" is an acronym which represents "Strengths", "Weaknesses", "Opportunities",

and "Threats". Note that a company's "Strengths" and its "Weaknesses" (its "flaws") are

obviously internal considerations. . In "Weaknesses", list any weaknesses along the value

chain of venture that must be strengthened to ensure success. Note that a company's

"Opportunities" and "Threats" in a company's operating environment are clearly external

considerations. Equally obvious is the fact that "Strengths" and "Opportunities" are both

positive considerations. "Weaknesses" and "Threats" are both negative considerations. To

express these relationships, it can be helpful to think of these factors in a 2 × 2 matrix

In order to do effective strategic planning, there are specific ways that this information

can be used by the company. In general, it is clear that the company should attempt -

to build its Strengths

to reverse (or disguise) its Weaknesses

to maximize the response to its Opportunities, and

to overcome its Threats.

Strengths It has the largest electricity generation capacity in Rajasthan Transmission & Distribution network of 1.1 million circuit km - the

largest in Rajasthan Potential for growth in this sector (demand exceeding supply)

Increasing focus on renewable sources of energy Government presence in this enterprise

Weaknesses Public sector players are only into generation of power Large demand-supply gap Unavailability of fuel and unwillingness of fuel suppliers to enter into bankable

contarcts Lack of necessary infrastructure to transport and store fuel, high cost risk

involved in transporting fuel

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Opportunities Huge population base Opportunities in Generation Ultra Mega Power Plants should be made into existence. Coal based plants at pithead which are untapped. Hydel power potential of 150,000 MW is untapped as assessed by the

Government of India. Renovation, modernisation, up-rating and life extension of old thermal and hydro

power plants.

Threats Competition from domestic players like NTPC Not a lucrative option for investors(ROE ) Rise in price of raw materials

Tariffs are distorted and do not cover cost

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Conclusion

-- KSTPS should emphasize on the conservation of environment, hazardous waste should

be properly eliminated but this is not the scene, some percentage of this killer waste goes

into the water of Chambal which is the drinking water source of Kota city, moreover fly

ash mixes with the surrounding air and can lead to chronic problems this need to be

checked

-- The machinery including boilers cooling pumps and other production equipments

should be regularly checked by best engineers so that they properly work and wastage of

fuel and water can be eliminated

-- The old machinery can be replaced with new and modern machinery.

-- The KSTPS can make contracts with other big players of the cement industry on the

India level like Ambuja Cement beside at Rajasthan level like Shree Cement Ltd. To

purchase their fly ash and use it as an ingredient of cement, this will help in some revenue

generation.

-- Collaboration with PSU’s like NTPC should be undertaken to have the advantage of

latest technology and knowledge workforce to improve the effectiveness and efficiency.

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References

1. http://en.wikipedia.org/wiki/Thermal_power_station

2. http://en.wikipedia.org/wiki/Deaerator

3. http://en.wikipedia.org/wiki/Economiser

4. http://en.wikipedia.org/wiki/Regenerative_heat_exchanger

5. http://www.tva.gov/power/coalart.htm

6. http://www.google.co.in/images

7. http://wapedia.mobi

8. http://images.google.co.in/images

9. http://www.rerc.gov.in

10. http://www.rvunl.com

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