GENERAL DESCRIPTION

PAGE

4

REPORT ON SIX WEEKS INDUSTRIAL TRAININGSUBMITTED FOR THE PARTIAL FULFILLMENT OF THE DEGREEOF BACHELOR OF TECHNOLOGY(MECHANICAL ENGINEERING)SUBMITTED BY :- SUBMITTED TO:-

SAHIL KUMAR KAMRA MR.MUNISH KUMAR &

ROLL NO.1250736 GURNAM SINGH

B.TECH (M.E) (Training Incharge)

(Mech. Dept.)

We take this opportunity to express our gratitude to our project guide, training manager and esteemed personality MR.R.K.SINGLA under whose expert guidance we completed our project successfully. We are grateful for his encouragement, valuable suggestions and guidance. He provided us with valuable tips and solutions to our repeatedly occurring problems. Our sincere, effective and deep gratitude is due to him for his excellent spirit, effective guidance, which gave us the confidence to complete the work of training and project work.

We are also thankful to the Technical Training Cell (T.T.C) at G.N.D.T.P. Bathinda. MR.ANIL SHARMA who introduced us to the problem and provided us with valuable data, without which our project could not come to an existence. They were instrumental in providing us with various lines to think on.

We are also thankful to our friends and class mates for their constructive criticism. They helped us a lot in completing our project successfully.

SERIAL NO.

CONTENT

PAGE NO.

1

INTRODUCTION

5

2

BRIEF HISRORY OF PLANT

6

3

CONTRIBUTION OF THE PLANT

7

4

HISTORY OF THE THERMAL POWER PRODUCTION

8

5

WORKING OF THE THERMAL PLANT

10

6

PLANT SALIENT FEATURES

13

7

BASICS OF THE THERMAL POWER PLANT

15

8

GENERAL DESCRIPTION

21

9

GENERAL ASPECTS OF BOILER

25

10

ID FAN

31

11

FD FAN

34

12

PA FAN

37

13

CONCLUSION

40

Guru Nanak Dev Thermal Power Plant is a coal-based plant. The requirement of coal for four units based on specific fuel consumption of 0.60 kg / kwh . The conveying and crushing system will have the same capacity as that of the unloading system. The coal comes in as large pieces. This coal is fed to primary crushers, which reduce the size of coal pieces from 400mm to 150mm. Then the coal is sent to secondary crusher through forward conveyors where it is crushed from 150mm to 200mm as required at the mills. Then the coal is sent to boilers with the help of primary fans. The coal is burnt in the boiler. Boiler includes the pipes carrying water through them; heat produced from the combustion of coal is used to convert water in pipes into steam. This steam generated is used to run the turbine. When turbine rotates, the shaft of generator, which is mechanically coupled to the shaft of turbine, gets rotated so, three phase electric supply is produced.

The basic requirements are:-

Fuel (coal)

Boiler

Steam turbine

Generator

Ash handling system

Unit auxiliaries

BRIEFDue to high rate of increasing population day by day, widening gap between power demand and its availability was one the basic reason for envisaging the G.N.D.T.P. for the state of Punjab. The other factors favoring the installation of the thermal power station were low initial cost and comparatively less gestation period as compared to hydro electric generating stations. The foundation stone of G.N.D.T.P. at bathinda was laid on 19th November 1969, the auspicious occasion of 500th birth anniversary of great Guru Nanak Dev Ji.

The historic town of bathinda was selected for this first and prestigious thermal project of the state due to its good railway connections for fast transportations of coal, availability of canal water and proximity to load center.

The total installed capacity of the power station 440MW with four units of 110MW each. The first unit of the plant was commissioned in September, 1974. Subsequently second, third and fourth units started generation in September 1975, March 1978, January 1979 respectively. The power available from this plant gives spin to the wheels of industry and agricultural pumping sets.

Guru Nanak Dev Thermal Plant, Bathinda, in addition to indirect contribution in various facts of state economy, is also responsible for:-

Narrowing the gap between power demand and power availability of the state.

Providing employment potentials to thousands of workers.

Covering the backward surrounding area into fully developed Industrial Township.

Providing additional relief to agricultural pumping sets to meet the irrigation needs for enhancing the agriculture production.

Reliability and improvement in continuity of supply and system voltage.

Achieving cent percent rural electrification of the state.

Although electric power generation in India on a commercial basis is almost a century old, substantial power development efforts began only after independence. At the launch of the First Five-Year plan in 1951, power generation was recognized as a major input for the country's economic development and was accorded high priority. Power sector outlays have been among the highest in successive Five-Year Plans ever since. The first two Plans focused on hydro power (as component of multi-purpose projects). Subsequent plans emphasized on rapid installations of thermal power stations.

As a result of Plan efforts, India's installed power generation capacity grew to 16,664 MW in 1974. However, assessment of the planned growth since 1951 indicated that with the uneven distribution of resources, power development with only States as spatial units, would result in large inter-state imbalances. This, and the need for quicker and greater capacity addition, led the Government of India to assume a leading role in large scale power generation as a matter of policy and, through an amendment of the Electricity (Supply) Act, National Thermal Power Corporation Ltd. (NTPC) and National Hydroelectric Power Corporation Ltd. (NHPC) were set up in the central sector to supplement the efforts of the States.

Consequently, total installed capacity of power utilities has increased from 1,362 MW in 1947 to 104918 MW in March, 2002. Electricity generation, which was only about 4.1 billion units in 1947, has risen to 515 billion units in 2001-02.

PRESENT SCENARIO :-

As on March 2003, the total installed capacity of utilities stood at 104,918 MW. Most of this installed capacity is under government control. The state governments control nearly 60% of the power generating capacity. Currently, the central government owns about 30% of the power generating capacity in the country, the majority of which is in the thermal sector. Of the total installed thermal capacity of 25366.50 MW in Central sector, NTPC's share is 20092 MW (76.61%).

Source

Central

State

Private

Total

% shareof total

Coal

21417.51

36302

4414.38

62130.89

59.22

Gas

4419.00

2661.70

4082.40

11163.10

10.64

Diesel

0

582.89

551.94

1134.80

1.08

Total Thermal

25836.51

39546.59

9045.72

74428.82

70.94

Hydro

3049.00

22636.0

576.20

26261.22

25.03

Nuclear

2720.00

0

0

2720.00

2.59

Wind

0

62.86

1444.60

1507.46

1.44

Total

31605.51

62245.47

11066.52

104917.5

100.00

Coal received from collieries in the rail wagon is mechanically unloaded by Wagon Tippler and carried by belt Conveyor System Boiler Raw Coal Bunkers after crushing in the coal crusher. The crushed coal when not required for Raw Coal Bunker is carried to the coal storage area through belt conveyor. The raw coal feeder regulates the quantity of coal from coal bunker to the coal mill, where the coal is pulverized to a fine powder. The pulverized coal is then sucked by the vapour fan and finally stored in pulverized coal bunkers. The pulverized coal is then pushed to boiler furnace with the help of hot air steam supplied by primary air fan. The coal being in pulverized state gets burnt immediately in the boiler furnace, which is comprised of water tube wall all around through which water circulates. The water gets converted into steam by heat released by the combustion of fuel in the furnace. The air required for the combustion if coal is supplied by forced draught fan. This air is however heated by the outgoing flue gases in the air heaters before entering the furnace.

The products of combustion in the furnace are the flue gases and the ash. About 20% of the ash falls in the bottom ash hopper of the boiler and is periodically removed mechanically. The remaining ash carried by the flue gases, is separated in the electrostatic precipitators and further disposed off in the ash damping area. The cleaner flue gases are let off to atmosphere through the chimney by induced draught fan.

The chemically treated water running through the water walls of boiler furnace gets evaporated at high temperature into steam by absorption of furnace heat. The steam is further heated in the super heater. The dry steam at high temperature is then led to the turbine comprising of three cylinders. The thermal energy of this steam is utilized in turbine for rotating its shaft at high speed. The steam discharged from high pressure (H.P.) turbine is returned to boiler reheater for heating it once again before passing it into the medium pressure (M.P.) turbine. The steam is then let to the coupled to turbine shaft is the rotor of the generator, which produces electricity.

The steam after doing the useful work in turbine is condensed to water in the condenser for recycling in the boiler. The water is pumped to deaerator from the condenser by the condensate extraction pumps after being heated in the low pressure heater (L.P.H)from the deaerator, a hot water storage tank. The boiler feed pump discharge feed water to boiler at the economizer by the hot flue gases leaving the boiler, before entering the boiler drum to which the water walls and super heater of boiler are connected.

PROJECT AREA:-

Power plant 238 acres

Ash disposal 845

Lake180

Residential colony285

Marshalling yard256

Total area1804

TOTAL COST:-Rs. 115 crores

STATION CAPACITY:-four units of 110MW. Each

BOILER:-

ManufacturersB.H.E.L.

Maximum continuous rating (M.C.R.)375 T/hr.

Superheater outlet pressure 139 kg/cm

Reheater outlet pressure 33.8 kg/cm

Final superheater/reheater temperature 540(C

Feed water temperature 240(C

Efficiency 86%

Coal consumption per day per unit1400 tones (Approximate)

STEAM TURBINE:-

ManufacturersB.H.E.L.

Rated output 110 MW.

Rated speed3000 r.p.m.

Number of cylindersthree

Rated pressure130 kg/cm

Rated temperature 535(C

Condenser vacuum0.9 kg/cm

GENERATOR:-

Manufacturers B.H.E.L.

Rated output

(Unit- 1 & 2)125000KVA

(Unit -3 & 4)137000KVA

Generator voltage11000 volts

Rated phase current

(unit 1 & 2)6560 Amps.

(unit 3 & 4)7220 Amps.

Generator coolinghydrogen

BOILER FEED PUMPS:-

Number per unittwo of 100% duty each

Type centrifugal

Rated discharge 445 T/hr.

Discharge head1960 MWC.

Speed 4500 r.p.m.

CIRCULATING WATER PUMPS:-

Numbers for two units five of 50% duty each

Type mixed flow

Rated discharge 8600 T/hr.

Discharge head24 MWC.

COOLING TOWERS:-

Numbers four

Water cooled 18000 T/hr.

Cooling range10(C

Height 120/122 metres

COAL PULVERISING MILLS:-

Numbers three per unit

Type drum-ball

Rated output 27 T/hr.

Thermodynamics is the main subject of Thermal Engineering. It deals with the behavior of gases and vapors, when they are subjected to varying temperatures and pressure. In a thermal power plant, heat energy of the steam is converted to mechanical energy of the turbine, which is further converted to electrical energy with the help of a generator. The simple circuit of thermal plant can be drawn as below:-

\

Some of the definitions dealing with the thermodynamics are as below:-

GAS:- A gas is the name given to the state of any substance of which the evaporation from the liquid state is complete. For example Hydrogen, Oxygen and air etc.

VAPOUR:-A vapor may be defined as a partially evaporated liquid and consists of the pure gas state along with particles of liquid in suspension. It does not behave in the same way as the gas, as the substance is further liable to the evaporation. When a vapor becomes completely evaporated, it is said to be dry and any further heating of a dry vapor is termed as super heating. Once a vapor is superheated it is approx. behaves as a gas.

HEATING OF A GAS:- A gas may be heated while either its volume is kept constant or its pressure is kept constant, when the volume is kept constant, the temperature, pressure will increase as the heat is supplied to a gas. But there will be no work done by the gas as there is no change in volume. But when the gas is heated at constant pressure then the volume increases and some work is done by the gas in expanding.

Work = pressure x change in volume

INTERNAL ENERGY OF GAS:- The internal energy of a gas is the heat energy stored in the gas. It is quantity of heat. If the quantity of steam is applied to a gas, the temperature of gas may increase or its volume may increase thus doing external work or it may do both, the result will depend upon certain set of conditions under which heat is supplied to gas. If this heating is accompanied by a rise of temperature, the gas will increase its internal energy. This means that some of the heat supplied has been stored in gas in the form of heat energy. Thus producing the rise of temperature the gas will have increased its internal energy. This means that some of the heat supplied has been stored in the form of heat energy, remaining is given out by gas as the form of external work as gas increased its volume. The increase in heat energy stored in the gas due to rise of temperature is called the increase of internal energy.LAW OF CONSERVATION OF ENERGY:-Total heat supplied to a gas must be equal to the increase of internal energy plus any external work done by the gas in expanding.

H = total heat supplied to gas

E = increase in internal energy

W = external work done by gas

Then H = W + E

ISOTHERMAL EXPANSION:- Heat can be supplied to a gas keeping its temperature constant. In this case the gas will expand doing external work equal to the amount of heat supplied. This type of expansion is called Isothermal Expansion.

ADIABATIC EXPANSION:- When a gas expands, doing external work in such a manner that no heat is supplied or rejected during the expansion. Such an expansion is called adiabatic expansion.

ENTHALPY :-The total heat of substance is known as its enthalpy.

BASIC TYPE OF STEAM POWER PLANT :- The conversion of heat energy of organic or nuclear fuel into mechanical energy with the aid of steam is carried out in steam power plant. A diagrammatic view of the simplest steam power plant is shown on next page :-

The initial state of the working body is assumed to be water, which at a certain temperature is compressed by the pump BFP and is fed into boiler B through economizer E. In the Boiler water is heated at constant pressure process (4-5), to its Boiling point. When the vaporization takes place in the same boiler process (5-6), since dry saturated steam is rarely used in power plants, it is superheated to the required temperature in superheated state.

The steam which is superheated through a pipe flows to steam turbine T. Where it undergoes adiabatic expansion producing some external work (process 1-2). To have the steam produce more work, its pressure at the turbine outlet must be as low as possible. For this purpose steam from turbine is exhausted to a special apparatus condenser C, in which the pressure of below atmosphere (vacuum) is created. In the condenser latent heat of vaporization is removed from the steam with the aid of cooling water and the steam condenses into liquid (the process of condensation 2-3) at a constant pressure and temperature. Then this cycle is reheated. The basic cycle of the steam power plant considered above is called the Rankine cycle.

(R = H1 H2

H1 Hw

where

(R = Rankine efficiency

H1 = enthalpy of steam at turbine inlet

H2 = enthalpy of steam at turbine outlet

Hw = enthalpy of condensate

METHODS OF INCREASING EFFICIENCY:-

Raising the initial steam pressure:- By increasing the initial pressure at turbine inlet, the enthalpy drop (H1 H2) can be increased. Thereby increase in thermal efficiency of Rankine cycle. However it must be mentioned that an increase in the initial steam pressure results in increase in the wetness of the steam at the end of expansion. The drops of liquid of steam can appearing in the steam at the last stage of the turbine cause erosion of blades and reduce overall efficiency of turbine.

In order to avoid this increase in steam wetness above the tolerated value, an increased temperature of the superheated steam as well as reheating may be employed.

REHEATING :-Reheating:- Reheating consists of subjecting steam to repeated super heating, after it

has expanded in the first cylinder of the turbine, at originally constant pressure in the reheaters to original temperature, then the steam is directed into the second cylinder of the turbine T2, where the steam expands and goes to the condenser. Reheating increases dryness fraction of steam. It also results in the thermal efficiency of the cycle.

Raising the temperature of superheating:- By raising the temperature of superheated steam at constant pressure, the heat drop (H1-H2) increases. As a result efficiency increases. Increasing the temperature of superheated steam also increases the dryness factor. In modern steam power plants the temperature of superheating is limited. By the heat resistant properties of the metal used.

Increasing the vacuum at condenser or reducing pressure at final:- A reduction in the final pressure increases the heat drop (H1-H2) which results in the increase in the thermal efficiency of the cycle.

Regenerative feed heat cycle:- In this system, the steam is fed from the turbine at certain points during its expansion and is utilized for preheating the feed water supplied to the boiler. At certain sections of turbine a small quantity of wet steam is drawn from the turbine. This steam is circulated around the feed water pipe leading from the hot well to boiler. The relatively cold water causes this steam to condensate. The heat thus lost by the steam being is transferred to the feed water; the condensed steam then drains into the hot well.

The net effect of this process is to supply the boiler with hotter water while a small amount of work is lost by the turbine. There is a slight increase in efficiency due to this process, but there efficiency depends upon following factors:-

( Steam pressure

( Degree of superheat in steam

( Reheat/nonreheat

( Vacuum in condenser

( Regenerative/ non regenerative cycle

BOILER FEED PUMP:-

As the heart is to human body, so is the boiler feed pump to the steam power plant. It is used for recycling feed water into the boiler at a high pressure for reconversion into steam. Two nos. 100% duty, barrel design, horizontal, centrifugal multistage feed pumps with hydraulic coupling are provided for each unit. This is the largest auxiliary of the power plant driven by 3500 KW electric motor.

The capacity of each boiler at GURU NANAK DEV THERMAL PLANT is 375 tones/hr. The pump which supplies feed water to the boiler is named as boiler feed pump. this is the largest auxiliary in the unit with 100% capacity which takes suction of feed water from feed water tank and supplies to the boiler drum after preheating the same in HP-1, HP-2 and economizer. The delivery capacity of each boiler feed pump is 445 tones/hr. to meet better requirements corresponding to the various loads, to control steam temperature, boiler make up water etc. The detailed particulars checking of protections and inter locks, starting permission etc. are as below:-

Particulars of BFP and its main motor:-

a) BOILER FEED PUMP:- The 110 MW turboset is provided with two boiler feed pumps, each of 100% of total quantity. It is of barrel design and is of horizontal arrangement, driven by an electric motor through a hydraulic coupling.

Type 200 KHI

No. of stages6

Delivery capacity445 t/hr.

Feed water temperature158(C

Speed 4500 rpm

Pressure at suction 8.30 kg/cm

Stuffing boxmechanical seal

Lubrication of pumpby oil under pressure

And motor bearingsupplied by hydraulic coupling

Consumption of cooling water230 L/min.

WATER TREATMENT PLANT:-

The water before it can be used in the boiler has to be chemically treated, since untreated water results in scale formation in the boiler tubes especially at high pressure and temperatures. The water is demineralised by Ion Exchange Process. The water treatment plant has production capacity of 1800 Tonnes per day for meeting the make-up water requirement of the power station.

COAL MILL:-

Coal Mill pulverizes the raw coal into a fine powder before it is burnt in the boiler furnace. The pulverizing of coal is achieved with the impact of falling steel balls, weighing 52.5 tonnes, contained in the mill drum rotating at a slow speed of 17.5 r.p.m. The raw coal is dried, before pulverizing, with inert hot flue gases tapped from the boiler. Three coal mills each with a pulverizing capacity of 27 T/hr. are provided for one unit.

INDUCED DRAUGHT FAN:-

Two nos. axial flow Induced Draught Fans are provided for each unit to exhaust ash laden flue gases from boiler furnace through dust extraction equipment and to chimney. The fan is driven by an electric motor through a flexible coupling and is equipped with remote controlled regulating vanes to balance draught conditions in the furnace. The fan is designed to handle hot flue gases with a small percentage of abrasive particles in suspension.

CONTROL ROOM:-

The control room is the operational nerve center of the power plant. The performance of all the equipments of the plant is constantly monitored here with the help of sophisticated instrumentation and controllers. Any adverse deviation in the parameters of various systems is immediately indicated by visual and audio warning and suitable corrective action is taken, accordingly. The control room is air conditioned to maintain the desired temperature for proper functioning of the instruments.

SWITCH YARD:-

Electricity generated at 11 KV by the turbo-set is stepped-up by unit transformers to 132/220 KV for further transmission through high tension lines to Maur, Muktsar, Malout, N.F.L., Sangrur and Ludhiana. Transmission of power to grid is controlled through 7 nos. 220 KV and 15 nos. 132 KV. Air Blast Circuit Breakers along with their associated protective systems.

WAGON TIPPLER:-

The coal received from the collieries, in more than 100 rail wagons a day, is unloaded mechanically by two nos. wagon tipplers out of which one serves as a standby. Each loaded wagon is emptied by tippling it in the underground coal hopper from where the coal is carried by conveyor to the crusher house. Arrangements have been provided for weighing each rail wagon before and after tippling. Each tippler is capable of unloading 6-8 rail wagons of 55 tonnes capacity in an hour.

CRUSHER HOUSE:-

Coal unloaded by the wagon tippler is carried to crusher house through conveyors for crushing. Two nos. hammer type coal crushers are provided, which can crush coal to a size of 10 mm. The crushed coal is then supplied to Boiler Raw Coal Bunkers. The surplus coal is carried to coal storage area by series of conveyors. Crushing of coal is an essential requirement for its optimum pulverizing and safe storage.

COOLING TOWERS:-

Cooling Towers of the power plant are the land mark of the Bathinda City even for a far distance of 8-10 kilometers. One cooling tower is provided for each unit for cooling 18000 tones of water per hour by 10(C. Cooling towers are massive ferro-concrete structure having hyperbolic profile creating natural draught of air responsible for achieving the cooling effect. Cooling tower is as high as 40 storey building.

BOILER:-

It is a single drum, balanced draught, natural circulation, reheat type, vertical combustion chamber consists of seamless steel tubes on all its sides through which water circulates and is converted into steam with the combustion of fuel. The temperature inside the furnace where the fuel is burnt is of the order of 1500(C. The entire boiler structure is of 42meter height.

BOILER CHIMNEY:-

The flue from the boiler, after removal of ash in the precipitators, are let off to atmosphere through boiler chimney, a tall ferro-concrete structure standing as high as the historic Qutab Minar. Four chimneys, one for each unit, are installed. The chimney is lined with fire bricks for protection of ferro-concrete against hot flue gases. A protective coating of acid resistant paint is applied outside on its top 10 meters.

CIRCULATING WATER PUMP:-

Two nos. of circulating water pumps provided for each unit, circulate water at the rate of 17200 T/hr. in a closed cycle comprising of Turbine Condenser and Cooling Tower. An additional Circulating Water Pump provided serves by for two units. The water requirement for bearing cooling of all the plant auxiliaries is also catered by these pumps.

GENERAL DESCRIPTION

The steam generator is of radiant, reheat, natural circulation, single drum, dry bottom and semi-out door type unit, designed for firing coal as principle fuel and the HFO oil firing capacity is equivalent to 22.5% boiler MCR, 4 LDO burners are capable for 7.5% boiler MCR heat input. Layout arrangement is of conventional type i.e. with the mills in front of the boiler. The complete furnace section is of fusion welded wall type, arranged as a gas and pressure tight envelop. The extended sidewall section (where re-heaters are located) is covered with water-cooled fin welded walls.

The super heater steam system has mainly three sections.

1. LTSH section (arranged in the back of the unit)

2. The radiant platen super heater (arranged at the outlet section of the furnace)

3. The final super heater (arranged after the re-heater).

Two numbers super heaters and de-super heaters are provided in between the LTSH section and platen super heater (in the connection links) for controlling super heated steam temperature over wide load range. The complete back pass of boiler (up to the economizer) has been covered with steam super heater wall sections.

The complete re-heater has been arranged as one section and located in the horizontal pass of the boiler in between the radiant platen super heater and final super heater. Two numbers re-heater, de-super heaters are provided for emergency control of the final reheat steam temperature.

The maximum flue gas velocity in the pressure part system is limited to 10-12 m/sec at 100% boiler MCR load.

All the headers in the pressure part system are provided with hand holes plate arrangement. All the headers are located out side the gas path, except for the economizer inlet header, intermediate headers and LTSH inlet header are located in the low gas temperature section. The complete pressure parts are suspended from the boiler structural steam roof sections and arranged for free expansion downward.

BOILER EFFICIENCY

Boiler efficiency is defined as the heat added to the working fluid expressed as a percentage of heat in fuel being burnt. The theoretical limit to boiler efficiency is 100% unlike in case of turbo generator, whose efficiency is limited by cycle efficiency. Boiler heat only because it would be extremely difficult and not a paying proposition to recover it all. Thus maximum boiler efficiency is thought in terms of an optimum efficiency, which depends on fuel being burnt and the fact that waste products of combustion take away heat with them.

Boiler efficiency depends solely on the boilers ability to burn the fuel and transfer the resulting heat to water and steam. The pressure and steam, although profoundly altering cycle efficiency and turbine efficiency, have no material effect on boiler efficiency.

The boiler efficiency will depend to great extent on the skill of their designing but there is no fundamental reason for any difference between a high pressure boiler and a low pressure boiler or between a reheat and non-reheat. Generally speaking a large boiler would be expected to be more efficient than small boiler, and as increase in pressure and temperature have developed; it has been accompanied by an increase in size. So there might be tendency to think that higher efficiency of most modern boiler is due to advance steam cycle condition where as it is infect attributable to increase in physical size and improvement in the art of boiler making in general fuel burning in particular.

A boiler, however must be able to meet the following design requirements :-

Be able to produce steam at required temperature and pressure over an appreciable range load take in feed at a temperature which varies with turbine load.

Be capable of following changes in demand for steam without excessive pressure swing.

Be reliable with high availability

LOW TEMPERATURE SUPER HEATER

The LTSH section is of continuous loops, plain tubular, drainable, horizontal, in line spaced type, with steam flow upwards and gas flow downwards arrangement. This section is in two blocks and located above the economizer section, in the back pass of the unit. This convective spaced bearing surface has 120 assemblies, 4 elements per assemblies. The out let section of LTSH alone is arranged vertically.

RADIANT PLATEN SUPER HEATER

The radiant platen super heater is of the continuous loop, plain, tubular, non-drainable, vertical inline tangent tube type, arrangement for parallel flow. The platen super heater section assemblies are widely spaced, and located in the radiant zone at the furnace outlet section. The radiant platen heating surface has 29 assemblies, 7 elements per assembly.

FINAL (FINISH PENDENT) SUPER HEATER (FSH)

Final pendent super heater (FSH) section, is of spaced type continuous loop, plain tubular, non-drainable, vertical in line spaced type, arranged for parallel flow. This FSH is located in the horizontal pass, after re-heater section. The convective final super heater has 89 assemblies-2 elements per assembly.

RE-HEATER SYSTEM

The re-heater section is single stage, spaced type, continuous loop and plain tubular, non-drainable, vertical inline spaced type, and arranged for parallel flow. The re-heater front pendent and rear pendent section is located in the horizontal pass, in between the radiant platen super heater and final super heater section. This convective re-heater section has 59 assemblies-6 elements per assembly. The approximately total convective heating surface is 3100 m. The entire re-heater section is suspended from the roof structural steel sections.

SUPER HEATER, DE-SUPER HEATER

For controlling the final super heat steam temperature at the rated valve, two numbers of spray type de-super heaters are located in the steam connecting links between the LTSH outlet header and platen SH inlet header, this inter stage de-super heater is of welded type. Spray tubes and liners are provided.

For emergency control of re-heater outlet temperature, two numbers of spray type de-super heater provided. These are located in the cold re-heat piping and used during any abnormal emergency conditions for steam temperature control. The de-super heaters are of welded type spray nozzles are provided.

ECONOMIZER SYSTEM

The economizer, a single block unit, is of continuous loop plain tubular, drainable, horizontal, in line arrangement with water flow upward and gas flow downwards. The economizer tubes are suspended from economizer intermediate header, using ladder type supports. The heating surface is 4550 m. An economizer re-circulative system is provided, connecting the down comer and economizer inlet pipe to ensure required flow through economizer tubes during starting conditions of the unit.

STEAM DRUM

The steam drum is of fusion-welded construction, fabricated from carbon steel plates. At each end of the drum, a manhole is provided to open inwards. The drum is located on the upper front of the unit, the ID of steam drum are welded type. The drum is equipped with primary turbo separators, secondary corrugated scrubbers and screen dryers, to the limit the solids carry over in the steam living in the drum. All turbo separators (along with scrubbers) and the screen dryers are of removable types. The drum is suspended from boiler roof structures.

DOWN COMER PIPES

There are six down comer pipes are provided, connecting the steam drum and water wall lower ring heater.

WATER WALL SYSTEM

The water wall system comprises of front wall, rear wall, side walls all of fusion-welded construction.

RISER PIPES

From the outlet headers of the water wall system, the steam water mixture is taken to the steam drum through 118 numbers pipes rolled up-risers.

WATER WALL/FURNACE DESIGN PRESSURS

The complete furnace wall, and the other steam cooled walls (in the second pass), are strengthen by providing buck stays and tie bars system to with stand pressure/forces

SUPPORTS/SUSPENSION

The complete circulation system is suspended from boiler roof structure & is arranged for free expansion downwards.

FURNACE

The furnace hopper outlet section is provided with an opening of approx.1100 mm depth for full width of the furnace. On each sidewall, in the furnace hopper area, one water-cooled access door (oval in shape) is provided. These openings are provided for taking maintenance cradle parts/ scaffolding sections etc. inside the furnace during maintenance of the furnace.

SPECIAL FITTING AND VALVES

Access doors, feed water valves, gauge glasses and safety valves etc. are included under this heading. The access doors are installed at:

FEED REGULATION STATION

The location of this station is at AB elevation and feed water supply to the boiler is regulating through this station. During initial period of starting the unit, feed is regulated through 30% line because the requirement of water is small during this period.

INDUCED DRAFT FAN

FUNCTIONS:

1. To remove flue gases from the furnace and throw it in a atmosphere through chimney.

2. To maintain ive pressure (draft) in the furnace i.e. 5 mm WC to 7 mm WC.

The type AN fan operates according to the impulse principle. The major part of the energy transferred to the gas appears as the velocity energy after the impeller. This velocity energy is converted into pressure energy by the diffuser. Usually, the AN fans are driven at constant speed and the flow is controlled by changing the direction of gas entering to impeller blades. For this purpose, adjustable guide vanes are used before the impeller.

TECHNICAL SPECIFICATIONS: -

1. Type: AN 25e6

where

AN axial non-profiled bladed fan 25- Nominal tip dia of impeller in decimeter

e6 type of diffuser

2. No of fans: 3

3. Medium Handled: Flue gas

4. Location: Ground

5. Orientation: Inlet vertical

: Outlet horizontal

FAN DESIGN RATING

6. Capacity: 230 m3/s

7. Total head developed: 350 mm WC

8. Temperature of medium: 1500 C

9. Specific weight medium: 0.813 Kg/m3

10. Speed : 980rpm

FAN RESERVE

11. Flow: 35.7%

12. Pressure: 38.3 %

FAN DRIVE COUPLING

13.Make: BHEL

14.Type : Flexible

DRIVE MOTOR

15.Make: BHEL

16.Frame size : AC 14256 H6 A8H

17.Type: Square cage induction

18.Rating: 1300KW

19.Speed: 980rpm

20.Fan weight: 21.7 tons

LUBRICATION

21.Fan:Grease Servo Gem EP2

22.Motor:FOLS Mobile DTE of IOC

23.Type of fan regulation:Inlet guide vane

BEARINGS

24.Fan fixed bearing: Anti friction 22328 C3

25.Fan expansion bearing : Anti friction 22232 C3 STARTING PERMISSIVES: -

1.Suction and discharge damper in closed position.

2.Central actuator or regulating vane in minimum position.

3.Central station on manual position.

4.Stack path available.

5.Lubricant oil system O.K. (from local fan panel ). For this condition to be O.K. following is required: -

a) Fan bearing (DE and NDE) temperature normal 950 C.

b) Motor bearing (DE and NDE) temperature normal 750 C.

c) Lubricant oil pressure O.K. 1.5 Kg/cm2.

d) Control supply of fan panel should be on.

6.Local push button reset.

TRIPPINGS

Lubricant oil pressure 0.4 Kg/cm2 with a delay of approximate of 0.45 seconds.

Motor bearing temperature very high 850C.

Fan bearing temperature very high 1050 C.

PARAMETER BEING0MONITORED DURING RUNNIG OF FAN

UCB LOCAL

Meter current1. Fan ( DE and NDE) bearing temperature

Vane position2. Motor bearing ( DE and NDE) temperature

3. Lubricant oil pressure

4. Lubricant oil temperature

5. Running of pump A or B.

FORCED DRAFT FAN

FUNCTION:

1. To supply air at required pressure to furnace for proper combustion.

2. To control the quantity of air in the furnace.

In the axial reaction fans (Type A P), the major part of ( about 80%) energy transferred is converted into static pressure in the impeller itself. The rest of the energy is converted into static pressure in the diffuser. These fans are generally driven at constant pace. The flow is controlled by varying the angle of incidence of impeller blades. It therefore becomes possible by this process to achieve high efficiencies even during part load operation.

TECHNICAL SPECIFICATIONS:

Type: A.P. I-18/11

Where A.P.-1. Single stage axial profile bladed fan.

18- Nominal tip dia of impeller in decimeter

11- Nominal hub dia of impeller in decimeter.

No of fans: 2 per boiler and both running

Medium handled : Air

Location: Ground

Orientation: inlet vertical outlet horizontal

FAN DESIGN RATING

Capacity: 110m3/s

Total Head developed : 520 mm WC

Temperature of medium: 500C

Specific Weight medium: 1.044 Kg/m3

Speed: 1480rpm

FAN RESERVE

Flow: 43%

Pressure: 49%

FAN DRIVE COUPLING

Make : Unique transmission

Type : RIG/FLEX COUPLING

DRIVE MOTOR

Make: BHEL

Frame Size: MC 74224 H4 A8H

Type: Square cage induction

Rating : 750 KW

Speed: 1480 rpm

Fan weight: 8.4 tons

LUBRICATION

Fan : FLOS ISO VG 68

Type of fan regulation : Blade pitch control

BEARING

Fan fixed bearing: 7230 BUA

Fan free bearing: NU 230 C3

RECOMMENDED BEARING RADIAL CLEARANCES

Before mounting: 0.115 mm to 0.150mm

After mounting: 0.065 mm to 0.100mm

OPERATION OF FD FAN : -

1. One FD fan should be running for starting one FD fan and two ID fans should be running for starting second FD fan.

2. Discharge damper should be in closed condition.

3. Control station should be on Manual Mode.

4. Regulating vane or controlled actuator should be in minimum position.

5. Lubricant oil system O.K. from fan pane. This includes:

a. Control oil pressure after pumps should be adequate i.e. 8 Kg/cm2.

b. NDE/DE bearing temperature of fan normal 950 C.

c. NDE/DE bearing temperature of motor normal 750 C.

d. Control supply on.

6. Local push button reset.

TRIPPINGS: -

1. Lubricant oil pressure low (less than 0.4Kg/cm2).

2. Motor bearing temperature very high 850C.

3. Fan bearing temperature very high 1050C.

4. ID fan trip condition one ID fan will trip one FD fan and both ID fans will trip both FD fans.

Note:

Control vane of FD fan will not operate till control oil pressure is not adequate i.e. it should be 8 kg/cm2.

PRIMARY AIR FANFUNCTION: - P.A. fan is a part of F.D. fan system. It also supply air in the furnace for combustion. Air supplied by P.A. fan and F.D. fan combine together to make total air flow in the furnace.

Air supplied by P.A. fan is used to dry and transport the pulverized coal from coal mill to furnace and is referred to as primary air.

In this type of fans, the medium handled enters the impeller axially and after passing through the impeller leaves radially. A large part of the energy transferred to the medium is converted into pressure energy. Constant speed motors generally drive these fans. The output of the fan is usually controlled by inlet dampers or inlet guide vanes or by varying the speed of the fan by suitable speed control device.

TECHNICAL SPECIFICATIONS:

No. of fans:2

Type:NDV 22 TIEF

Where

NDV Radial single

suction simply supported

22 nominal tip dia of

impeller in decimeter

TIEF Type of impeller.

Medium handled: Air

Location: Ground

Orientation: Inlet 450 inclined, outlet

bottom horizontal

FAN DESIGN RATING

Capacity : 70 m3/ sec

Total head developed: 1220 mm WC

Temp of medium: 500C

Specific weight of medium: 1.044 Kg/m3

Speed: 1480 rpm

FAN RESERVE

Flow: 84.7%

Pressure: 51.5%

FAN DRIVE COUPLING

Make: VOITH

Type: Hydraulic

DRIVE MOTOR

Male: BHEL

Frame size: M C 75288 H4 ATH

Type: square cage induction

Rating: 1259 KW

Speed: 1480 rpm

Fan Weight: 18.9 tons

LUBRICATION

Fan: FLOS ISO VG 68

Motor: Servo gem 3

BEARINGS

Fan fixed bearing: SLEEVE BRG RT 70

Fan free bearing: SLEEVE BRG RT 70

RECOMMENDED BEARING CLEARANCES

Axial gap (A): 0.380 to 0.760 mm

Side clearance: 0.190 to 0.245mm

Oil clearance: 0.180 to 0.290 mm

OPERATION OF A PA FAN

STARTING PERMISIVERS: Discharge damper should be in the closed condition.

1. Control station should be in the manual mode.

2. Control actuator should be in minimum position.

3. The one FD fan should ON for starting single PA fan.

4. Lubricate oil system O.K. This comprises: -

i. Lubricant oil system O.K. and pressure should be adequate 0.8 Kg/cm2.

ii. Motor bearing temperature is less than 750 C.

iii. Fan bearing temperature O.K. less than 750 C.

iv. Hydraulic coupling oil tank temperature O.K. less than 600 C.

5. Local push button reset.

Spending my six week of training in Guru Nanak Dev Thermal Plant, Bathinda, I concluded that this is a very excellent industry of its own type. They have achieved milestones in the field of power generation. They guide well to every person in the industry i.e. trainees or any worker. I had an opportunity to work in various sections namely Boiler section, ID fan , FD fan, PA fan while attending various equipments and machines. I had got an endeverous knowledge about the handling of coal, various processes involved like unloading, belting, crushing and firing of coal. The other machines related to my field that I got familiar with boiler, turbine, compressors, condenser etc. I found that there existed a big gap between the working in an institute workshop and that in the industry. Above all the knowledge about the production of electricity from steam helped me a lot to discover and sort out my problems in my mind related to the steam turbine, their manufacture, their capacity, their angle of blades and their manufacturing. The training that I had undergone in this industry will definitely help me to apply theoretical knowledge to the practical situation with confidence.

INTRODUCTION

BRIEF HISTORY OF

PLANT

ACKNOWLEDGMENT

INDEX

CONTRIBUTION OF

THE PLANT

HISTORY OF THERMAL

POWER PRODUCTION

WORKING OF

THERMAL PLANT

PLANT SALIENT

FEATURES

BASICS OF THERMAL

POWER PLANT

GENERAL DESCRIPTION

GENERAL ASPECTS

OF BOILER

CONCLUSION