ME 2403 Power Plant

8/11/2019 ME 2403 Power Plant

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ME1354-POWER PLANT ENGINEERINGTwo Mark Questions and Answers

NIT - I

1! W"# is e$e%tri%it# t"e &ost %on'enient (or& o( ener)#*

Electricity is the only form of energy which is easy to produce, transport, easy to use and easy to control.

+! W"at are t"e di((erent t#,es o( ,ower ,$ants w"ere e$e%tri%it# is ,rodu%ed in u$k.uantities*

Electricity is produced in bulk quantities in power plants, which can be of the following types:

a) Thermal b) Nuclear

c) Hydraulic

d) as turbine, and

e) eothermal.3! W"at do #ou understand # ase $oad and ,eakin) $oad*

The base load is the load below which the demand ne!er falls and is supplied "##$ of the time.

The peaking load is the load that occurs for about "%$ of the time.

4! Listout t"e &a/or %ir%uits in t"e stea&0t"er&a$ ,ower ,$ant!

Thermal power plant consists of mainly four circuits

a) &oal and 'sh &ircuitb) 'ir and as &ircuit.

c) (eed water and team &ircuit5! W"at are t"e %onsiderations to e &ade w"i$e se$e%tin) a suita$e site (or a t"er&a$,$ant*

(or con!entional base load thermal power plants the following factors are to be considered: a) '!ailability of cooling water.

b) '!ailability of fuel.

c) *istance from the centre of gra!ity of load demand.

d) &ost of land. e) &haracter of soil.

f) +ain wind direction and water currents in cooling water source.

g) *isposal of ash.

h) 'ccommodation for staff. i) ail and road conditions.

-)ecurity considerations.

k) *ensity of population in the !icinity. l) *anger of earthquakes.

! W"at are t"e e$e&ents w"i%" %ontriute to t"e %ost o( e$e%tri%it#*

The elements which contribute to the cost of electricity are:

a) (ied costs. b) /peration and maintenance costs.

c) (uel costs.

d) 01hnetof electricity sent out per year.

2! W"at is t"e (un%tion o( a stea& )enerator*

' steam generator produces steam at the desired rate, at the desired pressure and temperature, by burning fuel in its

furnace.

! W"at is t"e di((eren%e etween a (ire tue oi$er and a water tue oi$er*

2n the fire tube boiler, the hot flue gases flow through the tubes which are surrounded by water, in a shell. 2n the water

tube boiler, water from a drum flows through the tubes and the hot gases flow o!er them. The entire unit is enclosed by firebrick structure.

! W"at is %a$$ed oi$er e((i%ien%#*


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3oiler efficiency is the ratio of the heat utili4ed for steam 5generation in a certain time, to the heat supplied by the fuelduring the same period.

1! W"at are t"e 'a$'es (itted to a oi$er*

The following are fitted to a boiler for its safe and efficient operation: a) afety !al!e6 discharges steam automatically from the boiler when the steam pressure eceeds the normal unit.

b) top !al!e 7 control the steam flow from the boiler to the prime mo!er.

c) (eed check !al!e 7 controls the supply of water into the boiler.

d) 3low down !al!e 7 *rains the water from the boiler along with sediment if any, whene!er required.

11! W"# ,re"eated air is su,,$ied in a oi$er*

upplying preheated air has the following ad!antages:a) (lame temperature is raised.

b) peed of combustion is increased.

c) Ecess air to be supplied for complete combustion can be reduced.

d) 8ossible to burn low grade fuels.

e) Heat lost in the stack gases is reduced.f) 3oiler efficiency increases.

1+! W"at is air ,re"eater*

'ir preheater is a heat echanger which transfers the heat from the outgoing ehaust gases to the incoming air which issupplied for combustion of fuel in the furnace. The use of preheated air assists early gasification and ignition of carbon,

and ensures complete combustion of fuel. The temperature of the preheated air !aries from 9%#& to ;##&.

13! W"at is an e%ono&i6er* Economi4er is a heat echanger which utili4es the waste heat from the ehaust gases to heat the feed water before its

entry in to the boiler. The ehaust temperature ranges from se of

wet steam in engines and turbines should be a!oided for the following reasons:

a) Erosion of engine cylinder or turbine blade surfaces.b) +iing of water particles with the lubricating oil reduces the efficiency of the lubrication system.1! W"at is Rankine E((i%ien%#*

Efficiency of the ankine cycle is the ratio of the enthalpy drop in the turbine to the heat supplied in the boiler.12! Listout t"e 'arious s#ste& and %o&,onents used in t"er&a$ ,ower ,$ant!

a) &oal Handling system.

b) 'sh and dust handling system.c) *raught.

d) High pressure boiler.

e) 8rime6mo!er.

f) &ondensers and cooling towersg) (eed water purification plant.

h) *ifferent components used as economi4er, super heater, feed heaters etc., to increase the thermal

efficiency of the plant.1! W"at is a sur)e tank*

' surge tank is a small =!ertical) reser!oir into which the water from the closed conduit flows in or flows out to

reduce the pressure swings. 2n this way the pressure swings are not transmitted to the closed conduit. The surge tank

pre!ents damage to the conduit due to water hammer that occurs when the water supply to the turbine is stopped suddenly.

1! W"at is t"e 7ra(t tue*


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The draft tube allows the turbine to be set abo!e the tailrace to facilitate inspection and maintenance. 3y diffuseraction =gradual enlargement in section) regains the ma-or portion of the kinetic energy or !elocity head at the runner outlet.

3y this way the draft tube reduces the eit loss

NIT - II

1! W"at are t"e trans(er e.ui,&ents o( %oa$ "and$in) ,$ant*

i) 3elt con!eyors ii) crew con!eyors iii) 3ucket ele!ators i!) rab bucket ele!ators.

+! W"at are t"e e.ui,&ents used (or as" %o$$e%tion*

i) Electrostatic precipitator ii) ra!itational eparator iii) &yclone separator i!) (ly ash scrubbers

3! W"at are t"e -asi% re.uire&ents o( )ood as" "and$in) s#ste&*

2t should be able to handle large clinkers, soot and dust with little personal attention.

2t should be capable to deal with ultimate plant capacity.

2t should be able to handle both wet fu?"d dry ash and operate with little noise.

8recautions must be taken to minimise the abrasi!e action of ashes.

/perating and maintenance charges should be minimum possible.

4! W"at are t"e 'arious o,erations o( as" "and$in) s#ste&*

'sh handling system comprises the following operations.

a) emo!al of ash from the furnace.

b) Transfer of ash from furnace =ash6hopper) to isolated storage place by con!eyors.

c) *isposal of stored ash.5! 7i((erentiate o'er(eed and under(eed stokers!

S.No Overfeed stoker Underfeed stoker

".&oal is supplied to the grate surface

abo!e the point of air admission.

&oal is fed on the grate surface

below the point of air admission.

9.

(uel and primary air supply takes

place in opposite direction to each

other.

(uel and primary air supply are

directed in same direction.

6flame burnerii) hort flame burner =or) Turbulent burner

iii) Tangential burner

i!) &yclone burner

! W"at are t"e di((erent t#,es o( &i$$ used (or ,u$'eri6in) t"e %oa$*

". 3all mill 9. 3all and ace mill


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Electrostatic precipitator is an electrically operated dust collector that is located in the path of flue gas between the furnaceAboiler and the stack

=chimney) to remo!e the particulate matter especially fly ash in case of pul!erised fuel burning.

11! W"at are t"e &a/or ste,s in dust %o$$e%tin) ,ro%ess o( E8P*

There are four principle steps in the dust collecting process of electrostatic precipitator.

2onisation of flue gas and charging of dust particles.

'ttraction of the negati!ely charged particles to the positi!ely collecting electrodes.

*eposition or discharging of the charged particles on the collecting electrodes.

*islodging of the deposited particles from the collecting electrodes by mechanical rapping.

1+! W"at are t"e (un%tions o( drau)"t s#ste&*

To supply sufficient quantity of air through the furnace for complete combustion of fuel.

To remo!e the gaseous products of combustion from the furnace.

To mo!e and ehaust the products of combustion to the atmosphere through the chimney.

13! 7istin)uis" etween Natura$ and Arti(i%ia$ drau)"t!

S.No Natural draught Artificial draught

".

*raught produced by a chimney due to

the difference between the weight of the

column of gases with in the chimney.

'ir is forced under pressure

through air preheater.

9.No eternal power is required to cause

draught.8ower is required to dri!e the fan.


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15! 7istin)uis" etween 9or%ed drau)"t and indu%ed drau)"t

SI.No Forced draught Induced draught

".The (an =(* fan) is located beforethe furnace.

The (an =2* fan) is located near thechimney base.

9.2t discharges air under pressure into

the furnace to chimney.

2t draws the burnt gases from the furnace

and blows into the chimney.


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o!erning of water turbine is defined as the operation of maintaining the speed of the turbine at constant under all operating

condition.! Na&e t"e %oo$ants used (or (ast reeder rea%tor!

i)@iquid metal =Na or Na0) ii) Helium =He) iii) &arbon di oide =&/9)

2! 7e(ine t"e ter& ;i) raphitereactor, ii) 3eryllium reactor, iii) 1ater =ordinary or hea!y water) reactor.

1+! Indi%ate t"e t#,es o( nu%$ear (ission rea%tor ,ower ,$ants o,eratin) in India!

8ressuri4ed Hea!y 1ater eactor 6 0akrapar, u-arat

8ressuri4ed Hea!y 1ater eactor 6 0alpakkam, Tamilnadu

8ressuri4ed Hea!y 1ater eactor 6 Narora 6 " D 9, >8

3oiling 1ater eactor 6 Tarapur, +aharashtra&'N*> 6 ana 8ratap agar

NIT- I?

1! W"at are t"e ad'anta)es o( diese$ ,ower ,$ant*

*iesel power plants can operate at higher thermal efficiency than thermal and can operate on wide

!ariety of fuels.

8lant can be started quickly and brought into ser!ice to pick up loads in a short time.The efficiency at part loads does not fall so much as that of a steam plant.

2t can respond to !arying loads without any difficulty.

@ess space is required for same capacity than thermal plant.

1ater required for cooling purposes is lesser than that of thermal plant.


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+! =ow diese$ ,ower ,$ants are %$assi(ied*

a) According to the construction

tationary diesel power plant8ackaged power plant

3arge mounted diesel power plant

as turbine operated diesel power plant

b) According to strokeTwo stroke diesel power plant

(our stroke diesel power plant

c) According to speed

@ow speed diesel engine+edium A High speed diesel engine

d) According to cooling system

1ater 6 to 6 water cooling diesel power plant

1ater 6 to 6 air cooling diesel power plant.

3! W"at are t"e a,,$i%ations o( diese$ ,ower ,$ant*

>sed as a peak load plants in combination with some other plants.

Iuite suitable for mobile power generation and are widely used in transportation systems consisting of rail

roads, ships, automobiles and aero planes.>sed as stand by power plants for other plants under emergency ser!ice.

*iesel power plants in the range of9+1 to %#+1 capacity are used as central stations.

4! Na&e t"e %o&,onents o( diese$ ,ower ,$ant!

". *iesel engine 9. 'ir intake system


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! =ow diese$ en)ines are %$assi(ied*

a) According to Speedlow speed

+ediumAHigh speed

b) According to cooling

1ater 6 to 6 water cooling diesel power plant1ater 6 to 6 air cooling diesel power plant.

! =ow t"e e((i%ien%# o( diese$ ,ower ,$ant is i&,ro'ed*

i)2mpro!ement in load factor.ii) 2mpro!ement in air filter actioniii) 8ro!iding waste heat reco!ery system to reco!er the heat from flue gas.

i!) /ption of parallel operation among diesel power generating gets for impro!ed loading and fuel economy.

1! =ow )as turines are %$assi(ied*

as turbines are classified as follows:

Type of @oad

8eak load plantstandby plants

3ase load plants

'pplication

a) 'ircraft b) @ocomoti!e c) +arine d) Transport Cyclea) /pen cycle plants b) &losed cycle plants.

Fuel

a) @iquid b) as c) olid. b) @ocomoti!e d) Transport b) as

NIT- ?

1! W"at are t"e di((erent t#,es o( )eot"er&a$ ,ower ,$ant*

*ry6steam system

1et steam system =or) @iquid6dominated systemHot dry rock systems

+agma tic =+olten rock) &hamber system

+! =ow OTE@ %#%$e %an e %$assi(ied*

/TE& cycle can be classified into two types.

/pen cycle or &laude cycle or team cycle or *irect cycle&lose cycle or 'nderson cycle or Kapour cycle or 2ndirect cycle

3! W"at are t"e ad'anta)es o( Tida$ ,ower ,$ant*

2t is much superior to hydro power plant, because it is totally independent of rain.2t is free from pollution.

2t has unique capacity to meet the peek demand effecti!ely.

2t does not demand large area of !aluable land.

4! W"at are t"e ad'anta)es o( ,u&,ed "#dro stora)e ,$ant*

@ow capital cost than other peak units2t can pickup load rapidly within a matter of few minutes.

8lants can be made to control by automation as well as as remote.

(ree from effects of en!ironmental pollution.

@ess power is required for pumping which is a!ailable at cheaper rate.5! W"at are t"e di((erent t#,es o( re%ei'ers and "e$iostats used in so$ar ,ower ,$ant*

Receivers: i) &a!ity recei!er eliostats: i) lass reflecting surface


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! 7e(ine (iAed %ost!

The fied costs are those cost which remains same for a gi!en capacity. 2t does not !ary with output. 2t includes a)

&apital cost of power plant, b) &apital cost of primary distribution, c) /ther capital cost.

2! W"at are t"e di((erent &et"ods used to %a$%u$ate t"e de,re%iation %ost o( ,ower ,$ant*

traight line method

inking fund methodiii) *iminishing !alue method

! 7e(ine de&and (a%tor!

2t is defined as the ratio of maimum load to connected load.

! 7e(ine a'era)e $oad!

:. '!erage load L energy consumed in 9; hours

9;L total energy

time period

1! 7e(ine Load (a%tor!

@oad factorL '!erage load

+aimum load or peak loadThe a!erage !alue of load factor for 2ndian power plant is G#$.

1! 7e(ine di'ersit# (a%tor!

um of indi!idual maimum demand

*i!ersity factor L MMMMMMMMMMMMMMMMMMMMMMMMMMMMMM

simultaneous ma!imum demand

11! 7e(ine ,eak di'ersit# (a%tor!

maimum effecti!e demand of consumer

8eak di!ersity factor LMMMMMMMMMMMMMMMMMMMMMMMMMMMM

demand of consumer during the system of peak demand

1+! 7e(ine ,$ant %a,a%it# (a%tor!

8lant capacity factor L '!erage load

8lant capacity

L peak load load factor

plant capacity

13! 7e(ine Load %ur'e!

2t is a graphical representation between load =k 1) and time =hours). The graph slows the !ariation in

power station.


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I&,ortant Essa# Questions

nit-1

". *raw the general layout of a team power plant =Thermal 8ower plant) and Eplain the !arious &ircuits

used in the power plant.

9. i!e the layout of a hydroelectric power plant and Eplain its !arious components also mention its

'd!antages and @imitation.


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;. 2ndicate the layout of the ehaust gas system and the function of each component.

%. 1hat are the !arious mechanical fuel in-ection systems used 2ndicate the salient features of each

system.B. 1hy the !arious engine parts are to be lubricated 2ndicate and eplain briefly the engine

lubrication system.

C. 1hat is meant by supercharging diesel engines 1hy it is used 2ndicate the features of

unicameral supercharging and turbo charging.. 1hat are the applications of diesel engine power plant +ention the range of applications.

G. *iscuss the influence of intercooling, reheating and regeneration on the gas turbine performance.

"#. Eplain briefly the principle of operation of gas turbine power plant.

"". Eplain briefly the open and closed gas turbine power plants. 2ndicate their relati!e merits anddemerits.

"9. 1ith suitable sketches, eplain the working of the combined steam turbine and gas turbine power

plant.

nit 5

". *raw the general layout of tidal power plant and eplain the working of different9. components.

ME 2403 Power Plant

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