Power Plant Engineering

M.P.NACHIMUTHU M.JAGANATHAN ENGINEERING COLLEGE

M.P.NACHIMUTHU M.JAGANATHAN ENGINEERING COLLEGE

B.E. DEGREE EXAMINATION

B.E. DEGREE EXAMINATION

EE 2252 - Power Plant Engineering

EE 2252 - Power Plant Engineering

#. Na$e t%e &o'r $a(or )ir)'it* in *tea$ +ower +lant. •

• Coal and ash circuitCoal and ash circuit •

• Air and flue gas circuitAir and flue gas circuit •

• Feed ater and stea! circuitFeed ater and stea! circuit •

• Cooling ater circuitCooling ater circuit

2. "%at )on*i*t* o& air an, &l'e ga* )ir)'it 2. "%at )on*i*t* o& air an, &l'e ga* )ir)'it

Air and flue gas circuit consists of

Air and flue gas circuit consists of forced draught fan" air#$re#heater" %oiler" furnace" su$erforced draught fan" air#$re#heater" %oiler" furnace" su$er heater" econo!iser" dust collector" induced draught fan

heater" econo!iser" dust collector" induced draught fan and chi!ne&.and chi!ne&. . "%at )on*i*t* o& &ee, water an, *tea$ &low )ir)'it i

. "%at )on*i*t* o& &ee, water an, *tea$ &low )ir)'it in *tea$ +owern *tea$ +ower

The feed ater and stea! flo circuit consists of feed $u!$" econo!iser %oiler dru! The feed ater and stea! flo circuit consists of feed $u!$" econo!iser %oiler dru! su$er heater" tur%ine and condenser.

su$er heater" tur%ine and condenser.

/. "%at )on*i*t* o& )ooling water )ir)'it an, )oal 0 a*% )ir)'it

/. "%at )on*i*t* o& )ooling water )ir)'it an, )oal 0 a*% )ir)'it in *tea$ +ower +lantin *tea$ +ower +lant

The cooling ater circuit consists of a $u!$" condenser and cooling toer. The coal and The cooling ater circuit consists of a $u!$" condenser and cooling toer. The coal and ash circuit consists of coal deli'er&" $re$aration of coal" handling of coal to the %oiler furnace" ash ash circuit consists of coal deli'er&" $re$aration of coal" handling of coal to the %oiler furnace" ash handling and ash storage.

handling and ash storage.

5. "%at i* t%e $ain +'r+o*e o& t%e re*er1oir 5. "%at i* t%e $ain +'r+o*e o& t%e re*er1oir

The !ain $ur$ose of reser'oir is to store ater recei'ed fro! catch!ents areas during the The !ain $ur$ose of reser'oir is to store ater recei'ed fro! catch!ents areas during the rain& seasons and su$$l& the sa!e during the dr& season.

rain& seasons and su$$l& the sa!e during the dr& season. . "%at i* t%e $ain +'r+o*e o& t%e ,a$

. "%at i* t%e $ain +'r+o*e o& t%e ,a$

The !ain $ur$ose of the da! is to increase the height of ater le'el and also to increase The !ain $ur$ose of the da! is to increase the height of ater le'el and also to increase the or(ing head of the h&draulic $oer $lant.

the or(ing head of the h&draulic $oer $lant. 3. "%4 tra*% ra) i* '*e,

3. "%4 tra*% ra) i* '*e,

The trash rac( is used to $re'ent the entr& of de%ris" hich !ight da!age the tur%ine The trash rac( is used to $re'ent the entr& of de%ris" hich !ight da!age the tur%ine runners and choc( u$ the no))le of i!$ulse tur%ine.

runners and choc( u$ the no))le of i!$ulse tur%ine. 6. "%at i* t%e '*e o&

6. "%at i* t%e '*e o& *'rge tan*'rge tan

The surge tan( is used to $ro'ide %etter regulation of ater $ressure in the s&ste!. The The surge tan( is used to $ro'ide %etter regulation of ater $ressure in the s&ste!. The surge tan( controls the ater hen the load on the tur%ine decreases and su$$lies ater hen the surge tan( controls the ater hen the load on the tur%ine decreases and su$$lies ater hen the load on the tur%ine increases. Thus" surge tan( controls the $ressure 'ariations resulting fro! the load on the tur%ine increases. Thus" surge tan( controls the $ressure 'ariations resulting fro! the ra$id changes in ater flo in $enstoc( and hence $re'ents ater ha!!er.

ra$id changes in ater flo in $enstoc( and hence $re'ents ater ha!!er. 7. "%at i* t%e &'n)tion o& 8ore 9a4

7. "%at i* t%e &'n)tion o& 8ore 9a4

*

*

Fore %a& is considered as naturall& $ro'ided surge tan(. It is te!$orar& ater storage hen the load on the $lant is reduced and $ro'ides ater for initial incre!ent on increasing load. #:. E;+lain a9o't +en*to)

The $i$e %eteen surge tan( and $ri!e !o'er is (non as $enstoc(. It is designed to ithstand high $ressure. It is !ade u$ of reinforced concrete. In 'er& cold areas" the $enstoc( is  %uried to $re'ent ice for!ation and to reduce the e+$ansion ,oints.

##. "%at i* t%e '*e o& *+ill "a4*

-$illa& is li(e a safet& 'al'e of the da!. It discharges !a,or flood ithout da!aging the da!. It (ee$s the reser'oir le'el %elo the !a+i!u! le'el alloed.

#2. "rite a9o't +ri$e $o1er*

ri!e !o'er con'erts the (inetic energ& of ater into !echanical energ& to $roduce electrical energ&. elton heel" tur%ine" Francis tur%ine" /a$lan tur%ine and ro$eller tur%ine are  $ri!e !o'ers used in h&draulic $oer $lants.

#. "%at are t%e '*e* o& air &ilter an, *'+er)%arger* in ,ie*el engine +ower +lant

The $ur$ose of air filter is to filter the air fro! dust and other sus$ended $articles. The  $ur$ose of su$er charger is to increase the $ressure of the engine to increase $oer of the engine.

#/. "%at i* t%e '*e o& ,ra&t t'9e

The draft tu%e is used to regain the (inetic energ& of ater co!ing out of reaction tur%ine. It ena%les the reaction tur%ine to %e $laced o'er tailrace le'el.

#5. "%at i* t%e &'n)tion-o& )ooling *4*te$ in !ie*el +ower +lant

The function of cooling s&ste! is to re!o'e heat fro! the engine c&linder to (ee$ the te!$erature of the c&linder in lo range and e+tend engine life.

#. "%at )on*i*t* o& l'9ri)ation *4*te$ in ,ie*el engine +ower +lant

The lu%rication s&ste! consists of oil $u!$s" oil tan(s" filters" coolers and connecting  $i$es. The $ur$ose of the lu%rication is to reduce the friction of !o'ing $arts and also $i$es to

reduce the ear and tear of !o'ing $arts.

#3. "%at i* t%e +'r+o*e o& inter)ooler in ga* t'r9ine +ower +lant

-ince the $oer re0uired to co!$ress the air is less in isother!al $rocess it is re0uired to !aintain the" te!$erature of air constant as far as $ossi%le. 1ence the air lea'ing the 2.. co!$ressor is cooled %& intercooler and then $assed to the 1. co!$ressor.

#6. Na$e two )o$9ine, +ower )4)le*

• Co!%ined c&cle of gas tur%ine and stea! $oer $lant. • Co!%ined c&cle of gas tur%ine and diesel $oer $lant.

#7. !e&ine t'r9o )%arging in )o$9ine, ga* t'r9ine an, ,ie*el )4)le*

In the co!%ined c&cle" the e+haust gas fro! the diesel engine is e+$anded in the tur%ine" hich is cou$led ith co!$ressor hich su$$lies $ressuri)ed air to the diesel engine. This increases diesel engine out$ut. This arrange!ent is (non as tur%o charging.

2:. "%at i* t%e $ain +'r+o*e o& %ig%-+re**'re 9oiler*

The high#$ressure %oilers are used to increase the efficienc& of the $lant and to reduce the cost of electricit& $roduction.

2#. State i$+ortant a,1antage* o& %ig%-+re**'re 9oiler*

• The a!ount of scale for!ation is less" since the 'elocit& of ater through $i$es are !ore. • All $arts of the s&ste! are heated unifor!l&" so there is no danger of o'erheating.

22. Na$e i$+ortant %ig% +re**'re 9oiler*

• 2a Mont %oiler  • Benson %oiler  • 2oeffler %oiler  • 4elo+ %oiler.

2. "rite a9o't La Mont 9oiler "%at i* t%e $a(or ,i*a,1antage o& La Mont 9oiler 2a Mont %oiler is a forced circulation high $ressure ater tu%e %oiler.

The !a,or disad'antage is the for!ation of %u%%les" salt and sedi!ent on the inner surfaces of the heating surfaces. This reduces the heat flo and stea! generation.

2/. "rite a9o't <en*on 9oiler State *o$e i$+ortant a,1antage* o& <en*on 9oiler

Benson %oiler is the high $ressure" 'ertical fire tu%e %oiler. This %oiler has no dru! and is 5designed to o$erate at critical $ressure of 336 %ar. Benson %oiler has no dru!. -o the total eight of the Benson %oiler is reduced %&#378" hen co!$ared to other %oilers.

o The erection of Benson %oiler is easier and 0uic(er.

25. "rite a9o't Loe&&ler 9oiler

The !a,or disad'antage in 2a Mont %oiler is the de$osition of salt and sedi!ent on the inner surface of the ater tu%es. It reduces the heat transfer and ulti!atel& the stea! generating ca$acit&.

In 2oeffler %oiler" this $ro%le! is sol'ed %& $re'enting ater fro! floing through the  %oiler tu%es. The stea! is generated outside the tu%es.

2. E;+lain Re%eat )4)le

If the dr&ness fraction of stea! lea'ing the tur%ine is less than 7.99" then" corrosion and erosion of tur%ine %lades occur. To a'oid this situation" reheat is used.

In the reheat c&cle" the e+$ansion of stea! ta(es $lace in one ;or< !ore#tur%ines. -tea! is e+$anded in the 1 tur%ine first" and then it is reheated. The reheated stea! is again e+$anded in. the 2 tur%ine.

23. "%at are t%e i$+ortant a,1antage* o& Re-%eating • Due to reheating" netor( done increases

• 1eat su$$l& increases

• Ther!al efficienc& increases

• Due to reheating" the tur%ine e+it dr&ness fraction increases so !oisture decreases # so  %lade erosion %eco!es !ini!u! # so life of the tur%ine ill %e increased.

26. Na$e ,i&&erent $et%o,* o& re%eating ;a< Gas Reheating

;%< 2i'e # stea! reheating

;c< Co!%ined gas li'e stea! reheater. 27. !e&ine 9lee,ing in *tea$ +ower +lant

Assu!e I (g of stea! is e+$anded in the tur%ine. Before co!$lete a!ount of stea! #is e+$anded" so!e a!ount of stea! ;! (g< is #e+tracted = E+tracting the stea! in the tur%ine %efore e+haust is called %leeding. This %led stea! is used to heat the feed ater.

:. E;+lain t%e ter$ Regeneration

Regeneration !eans heating the feed ater %& stea! ta(en fro! the tur%ine. The stea! is e+hausted ;%led< fro! the tur%ine at se'eral locations %efore e+haust and is su$$lied to regenerator ;feed ater heater< to heat the feed ater.

#. State *o$e a,1antage* o& Regeneration )4)le • 1eat su$$lied to %oiler %eco!es reduced

• Ther!al efficienc& is increased since the a'erage te!$erature of heat addition to the c&cle is increased.

• Due to %leeding in the tur%ine" erosion of tur%ine due to !oisture is reduced. 2. Na$e ,i&&erent $et%o,* '*e, to e;tra)t *tea$ &or %eating t%e &ee, water

• Direct contact heater  • Drain $u!$ !ethod • All drains to hot ell • Cascade s&ste!

. !e&ine t%e ter$ wa*te %eat re)o1er4

>aste heat is the heat hich is not at all used and e+hausted out as a aste $roduct. >aste heat is nor!all& a'aila%le fro! the industr& in the for! of $rocess stea! and ater at high te!$erature. Also" the aste heat is discharged ith the e+haust gases in so !an& industries. This heat can %e reco'ered for useful $ur$ose. This $rocess is (non# as aste heat reco'er&.

/. "%at are t%e wa*te $aterial*= w%i)% )an 9e '*e, &or &'el &or +ower generation

• Munici$al aste • Industrial aste • a$er aste • Ru%%er aste.

5 "rite a9o't wa*te %eat 9oiler*

The aste heat %oilers use the aste heat in gases co!ing out of diesel engines and gas tur%ines at high te!$erature ;or< use the aste as a fuel in the incineration.

-o!e %oilers use the industrial dirt& gases for $oer generation. . "rite a9o't &l'i,i*e, 9e, 9oiler*

>hen the high 'elocit& gas is $assed through a $ac(ed %ed of finel& di'ided solid  $articles" the $articles %eco!e sus$ended in the gas strea! and the $ac(ed %ed %eco!es a

fluidised %ed. >hen the gas 'elocit& is 'er& high" the fluidised %ed %eco!e tur%ulent and ra$id !i+ing of $articles occurs. @lti!atel&" the" %eha'iour of !i+ture solid $articles and #gas %eco!e a fluid. Burning of a fuel in such a state is (non as Fluidised Bed Co!%ustion. The %oiler $lant using this fluidised %ed co!%ustion is (non as fluidised %ed %oilers.

3. State *o$e a,1antage* o& &l'i,i*e, 9e, 9oiler*

• An& t&$e of fuel # solid" li0uid ;or< gaseous fuel ;or< do!estic and industrial aste can %e used in FBC s&ste!. An& t&$e# of co!%usti%le !atter can %e %urned %& ad,usting the factors as si)e" air 'elocit& and rate of feed.

• 1igh heat transfer rate is $ossi%le to the surfaces i!!ersed in the %ed" %ecause solid !i+ing is e+tre!el& $ossi%le.

• 1igh co!%ustion efficienc&.

• The solid fuel need not %e $ul'erised in fluidised %ed %oilers. 6. Na$e t%e two t4+e* o& )oal %an,ling

• Out $lant handling • In#$lant handling.

7. "rite a9o't o't-+lant %an,ling

Out $lant handling includes the handling of coal!ine to the ther!al $oer $lant. These handlings are outside the $lant in the folloing a&s.

• Trans$ortation %& sea ;or< ri'er  • Trans$ortation %& rail

• Trans$ortation %& road

• Trans$ortation of coal %& $i$eline. /:. "rite a9o't in+lant %an,ling o&-)oal

In order to handle large 0uantit& of coal inside the $lant" so!e !echanical handling s&ste!s are $ro'ided fr s!ooth" eas& and %etter controlled o$eration. The in$lant coal handling is di'ided" into folloing categories.

• Coal unloading • Coal $re$aration • Coal transfer  • Coal storage

/#. "%4 t%e +re+aration o& )oal i* ne)e**ar4

The coal fro! coal nines cannot %e directl& fed into the furnace. ro$er $re$aration of coal should %e done %efore feeding the coal to the furnace. In the coal $re$aration" the coal $asses through the different e0ui$!ents li(e *. Crushers 3. -i)ers :. Driers and Magnetic -e$arators. /2. Na$e t%e ,i&&erent t4+e* o& )oal tran*&or$ing e>'i+$ent*

*. Belt con'e&ors 3. -cre con'e&ors :. Buc(et ele'ators ?. Gra% %uc(et ele'ators 6. -(i$ hoists . Flight con'e&ors.

The coal transfer starts %& carr&ing of coal fro! #unloading $oint to the storage site. /. "%at i* t%e '*e o& 9elt )on1e4or*

Belt con'e&ors are !ostl& used for trans$orting coal o'er long distance ith large 0uantit&. An endless %elt is !ade to run o'er a $air of end dru!s and $ulle&s and su$$orted %& series of roller at regular inter'als.

//. "rite a9o't *)rew )on1e4or an, 9')et )on1e4or*

In scre con'e&or" an endless helicoid scre is fitted to the haft. On one end of the shaft" the dri'ing !echanis! is fitted and the other end of the shaft is su$$orted on a %all %earing. >hile the scre is rotating" the coal is transferred fro! one end to the other end.

Buc(et con'e&ors are used as 'ertical lifts. The coal is loaded at the %otto! and unloaded at the to$ in the %uc(et con'e&ors.

/5. !e&ine ,ra'g%t= w%at i* t%e '*e o& ,ra'g%t in t%er$al +ower +lant*

Draught is defined as a s!all $ressure difference re0uired %eteen the fuel %ed ;furnace< and outside air to !aintain constant flo of air and to discharge the gases through chi!ne& to the at!os$here. Draught can %e o%tained %& chi!ne&" fan" stea! ,et ;or< #air ,et ;or< co!%ination of these.

The uses are

• To su$$l& re0uired 0uantit& of air to the furnace for co!%ustion of fuel. • To dra the co!%ustion $roducts through the s&ste!.

• To re!o'e %urnt $roducts fro! the s&ste! /. "rite a9o't )la**i&i)ation o& ,ra'g%t

Draught is classified as *. Natural draught 3. Artificial draught

The artificial draught is further classified as ;a< -tea! ,et draught

;%< Mechanical draught ;c< Induced draught ;d< Forced draught

/3. !e&ine t%e ter$ Nat'ral ,ra'g%t an, w%at are t%e a,1antage* o& nat'ral ,ra'g%t *4*te$

The tall chi!ne& creates the natural draught %& the te!$erature difference %eteen hot gases in the chi!ne& and cold at!os$heric air outside the chi!ne&.

The ad'antages are

•  No e+ternal $oer is re0uired

• Air $ollution is less since gases are discharged at high le'el. •  No !aintenance cost

• Ca$ital cost is less than artificial draught. /6. "rite a9o't arti&i)ial ,ra'g%t

In !ode! $oer $lants" the draught should %e fle+i%le to !eet the fluctuating loads and it should %e inde$endent of at!os$heric conditions. To achie'e this" the aid of draft fans %eco!es !ust and %& e!$lo&ing the draft fans" the height of the chi!ne& ould %e reduced.

/7. "rite a9o't &or)e, ,ra'g%t *4*te$

In this s&ste!" the %loer ;forced draft fan< is located at the %ase of the %oiler near the grate. Air is forced to the furnace %& forced fan and the flue gases are forced to chi!ne& through econo!iser and air $reheater.

5:. "%at are t%e a,1antage* o& &or)e, ,ra'g%t *4*te$

• -ince the fan handles cold air" the fan si)e and the $oer re0uired are less. •  No need of ater cooled %earings %ecause the air %eing handled is cold air"

• ressure throughout the s&ste! is a%o'e at!os$heric $ressure so the air lea(age into

the furnace is reduced.

5#. How t%e in,')e, ,ra'g%t i* woring

In an induced draught s&ste!" a %loer ;induced draft fan< is $laced near ;or< at the %ase of the chi!ne&. The fan suc(s the flue gas fro! the furnace creating a $artial 'acuu! inside the furnace. Thus at!os$heric air is induced to flo through the furnace to aid the co!%ustion of fuel. The flue gases dran %& the fan $asses through chi!ne&" to the at!os$here.

52. "%4 t%e 9alan)e, ,ra'g%t *4*te$ i* +re&erre, t%an ot%er *4*te$

In the induced draught s&ste!" hen the furnace is o$ened for firing" the cold air enters the furnace and dilate the co!%ustion. In the forced draught s&ste!" hen the furnace is o$ened for firing" the high $ressure air ill tr& to %lo out suddenl& and furnace !a& sto$. 1ence the furnace cannot %e o$ened for firing ;0< ins$ection in %oth" s&ste!s. Balanced draught" hich is a co!%ination of induced and forced draught" is used to o'erco!e the a%o'e stated difficulties. 5. "%at i* t%e ,i&&eren)e 9etween *to)er &iring an, +'l1eri*e, &'el &iring

The stoc(er firing !ethod is used for firing solid coal here as $ul'erised firing !ethod is used for firing $ul'erised coal.

5/. "%at are-t%e ,i&&erent t4+e* o& *to)er* *. O'er feed stoc(ers

Tra'elling grate stoc(ers -$read stoc(ers

3. @nder feed stoc(ers

-ingle retort stoc(er  Multi retort stoc(er 

55. "%at i* t%e '*e o& +'l1eri*er an, na$e ,i&&erent t4+e* o& +'l1eri*ing $ill*

The $ul'eriser is used to $ul'erise the coal in order to increase the surface e+$osure. ul'erised coal ena%les ra$id co!%ustion. The different t&$es of $ul'erising !ills are

*. Ball !ill 3. 1a!!er !ill :. Ball and race !ill.

5. Na$e t%e two $et%o,* o& +'l1eri*e, &'el &iring *4*te$ *. @nit ;or< direct s&ste!

3. Bin ;or< central s&ste!.

53. "%at are a,1antage* o& 'nit ?or@ ,ire)t *4*te$ o& +'l1eri*e, &'el &iring *. The la&out is si!$le and econo!ical

3. It gi'es direct control of co!%ustion :. Coal trans$ortation s&ste! is si!$le ?. Maintenance cost is less

56. How t%e a*% %an,ling *4*te$ i* )la**i&ie, *. Mechanical handling s&ste!

3. 1&draulic s&ste! :. neu!atic s&ste! ?. -tea! ,et s&ste!

57. "%4 a*% %an,ling *4*te$ i* nee,e,

• To re!o'e the ashes fro! the furnace ash ho$$er 

• To trans$ort the ashes fro! furnace ash # ho$$er to a storage • To dis$ose the ashes fro! the storage

:. Na$e ,i&&erent t4+e* o& ,'*t )olle)tor* *. Mechanical Dust collector 

Gra'itational se$arators Bag house dust collector 

There are three t&$es of %ag house dust collector  • O$en $ressure t&$e

• Closed $ressure t&$e • Closed suction t&$e 3. C&clone. -e$arators

:. Elector -tatic reci$itator ;E-< #. "%at i* t%e $ain +'r+o*e o& )%i$ne4

The !ain $ur$ose of chi!ne& is to e!it the flue gases at a considera%le height to a'oid nuisance to the surrounding $eo$le.

2. "%at are t%e ,i&&erent t4+e* o& loa, a)t on t%e )%i$ne4 There are to t&$es of loads acting on the chi!ne& na!el&.

• Its on eight hich is considered to as a single 'ertical force acting through the centroid" and

• The >ind $ressure" hich is considered as the hori)ontal force acting on the centroid of 'ertical $ro,ected area.

. Na$e ,i&&erent t4+e* o& )%i$ne4 *. -teel chi!ne&

3. -ite constructed chi!ne& :. lastic chi!ne&

/. !e&ine &or)e, ,ra&t an, in,')e, ,ra&t )ooling tower*

If the fan is located at the %otto! of the toer and air is %lon %& the fan u$ through the descending ater it is called as forced draft cooling toers

If the fan is located at the to$ of the toer and air enters through the lou'ers located on the toers side and dran u$ and discharge through the fan casing" it is called as induced draft.

5. "%at are t%e a,1antage* o& in,')e, ,ra&t )ooling tower o1er &or)e, ,ra&t )ooling tower

i. The outlet ater co!es in contact ith the driest air and ar!est ater co!es in contact ith !ost hu!id air.

ii. The re#circulation is seldo! a $ro%le!.

iii. The first cost is lo due to the reduction in $u!$ $oer consu!$tion. . "%at are t%e a,1antage* o& %4+er9oli) nat'ral-,ra&t )ooling tower*

• -ince no fans are used $oer cost and au+iliar& e0ui$!ents cost is reduced. • 1&$er%olic toer chi!ne& creates its on draft e'en hen there is no ind • Ground fogging and ar! air re#circulation are a'oided in h&$er%olic toers • The structure is !ore or less self#su$$orted.

3. "%at are t%e &a)tor* t%at a&&e)t t%e rate o& e1a+oration o& water in )ooling tower*

• A!ount of ater surface area e+$osed • The ti!e of e+$osure

• The relati'e 'elocit& of air $assing o'er the dro$lets • The R1 of air

• The direction of airflo relati'e to ater.

6. "%at i* t%e woring +rin)i+le o& Cooling Tower*

The hot ater is s$ra&ed fro! the to$ of the toer" hile the air is !ade to flo fro! the  %otto! of the toer to the to$. This air cools the hot ater in the cooling toer. Air 'a$orises a

s!all $ercentage of ater" there %& cooling the re!aining ater. The air a%sor%s the heat and lea'es at the to$ of the toer and cooled ater lea'es at the %otto! and recirculated to the condenser.

7. Na$e ,i&&erent t4+e* o& )ooling tower* The cooling toers are classified as follos. ;a< According to the construction of !aterial

*. Ti!%er # for s!all toer 

3. Ferro concrete # for large ca$acit& stations.

:. Multi dec( concrete toers # for large stea! stations ?. Metallic

;%< According to the nature of air draught#

*. At!os$heric ;or< Natural draught cooling s&ste! 3. Mechanical draught cooling toer.

3:. How t%e at$o*+%eri) ?or@ nat'ral ,ra'g%t )ooling tower*- are )la**i&ie,

In at!os$heric ;or< natural cooling toers" the natural air $ro'ides the re0uired cooling ithout the use of fans. This is classified into three t&$es.

*. Natural draft s$ra& filled toers 3. Natural draft $ac(ed t&$e toers.= :. 1&$er%olic cooling toers

3#. How $e)%ani)al ,ra&t )ooling tower* are )la**i&ie,

Mechanical draft cooling toer is classified into three t&$es *. Forced draft toer.

3. Induced draft counter flo toer  :. Induced draft cross flo toer.

32. How t%e ,r4 t4+e )ooling tower* are )la**i&ie,

The dr& t&$e cooling toers are classified into to t&$es =as follos. *. Indirect dr& t&$e ;or< 1eller cooling s&ste!

3. Direct dr& t&$e#cooling s&ste!

3. "%at are t%e $et%o,* to re,')e t%e e&&e)t* o& +arti)'late*

The effects of $articulates can %e reduced %& the folloing !ethods. • Coal cleaning

• @sing i!$ro'ed electrostatic $reci$itator design

• Controlling the dust ithin alloa%le li!it. This can %e done %& increasing the height of chi!ne& there%& reducing the concentration

3/. "%at are t%e e>'i+$ent* '*e, &or a*% )olle)tion • Electrostatic $reci$itator 

• Fl& ash scru%%ers • Cinder catcher 

• C&clone dust collector 

35. "%at i* $eant 94 !e*'l+%'ri*ation an, na$e t%e $et%o,* a,o+te, &or ,e*'l+%'ri*ation

Desul$hurisation of fuel is the $rocess of reducing the sul$hur content in the fuel. The folloing !ethods are ado$ted for desul$hurisation.

*. Che!ical treat!ent 3. Forth flotation :. Magnetic se$aration

3. "%at are t%e $et%o,* a,o+te, to re$o1e S:2 &l'e ga*e* *. >et scru%%ing

3. -olid a%sor%ent :. Catal&tic o+idation 33. "rite a9o't C:2 re)or,er*

In ther!al $oer $lants" it is necessar& to (ee$ the concentration Of C73 as lo is necessar& as $ossi%le. To achie'e this" a constant recording of concentration Of C73

These recorders are %ased on the three different $rinci$les" as gi'en %elo. *. Ther!al conducti'it& cell

3. Che!ical a%sor$tion cell

:. Densit& %alance 3. >hat is the# necessit& of Auto!atic controls for feed ater

The electrical load on $oer $lant 'aries in an irregular !anner. The auto!atic control  $ro'ided at a stea! $oer $lant successfull& !eets o'er the 'aria%le load. The auto!atic control

for feed ater is necessar& sine the su$$l& of feed ater de$ends u$on $lant load. 36. Na$e *o$e o& t%e a'to$ati) )ontrolling $et%o,* &or &ee, water

*. -ingle ele!ent $ilot o$erated s&ste! 3. -ingle ele!ent self o$erated s&ste! :. To ele!ent $ilot o$erated s&ste! ?. Three ele!ent $ilot o$erated s&ste!

37. "%at i* t%e +'r+o*e o& a'to$ati)= )o$9'*tion )#ritrol

The !ain $ur$ose of #auto!atic co!%ustion= control s&ste! is to !aintain load against de!and" to $re'ent s!o(e" to increase %oiler house efficienc&" to carr& out routine ad,ust!ents and to $ro'ide interloc(ing safe guards.

6:. "%at are t%e a++lian)e* nown a* 9oiler a))e**orie*

The a$$liances used to increase the efficienc& of the %oiler are (non as %oiler accessories.

The i!$ortant %oiler accessories are

*. Econo!iser 3. -u$erheater :. Air $reheater ?. Feed $u!$ 6. In,ector 6#. "%at are t%e $et%o,* a,o+te, to re$o1e SO2 &ro$ ,'e ga*e*

*. >et scru%%ing 3. -olid a%sor%ent :. Catal&tic o+idation 62. "rite a9o't C:2 re)or,er*

In ther!al $oer $lants" it is necessar&" to (ee$ the concentration of C73 as lo as $ossi%le. To achie'e this = a constant recording of concentration of C73 is necessar&.

These recorders are %ased on the three different $rinci$les" as gi'en %elo. *. Ther!al conducti'it& cell

3. Che!ical a%sor$tion cell :. Densit&# %alance

6. "%at i* t%e ne)e**it4 o& A'to$ati) )ontrol* &or &ee, water

The electrical load on $oer $lant 'aries irregular !anner. The auto!atic !an control  $ro'ided at a stea! $oer $lant successfull& !eets o'er the 'aria%le load. The auto!atic control

for feed ater is necessar& sine the su$$l& of feedater de$ends u$on $lant load. 6/. Na$e *o$e o& t%e a'to$ati) )ontrolling $et%o,* &or &ee, water

• A single ele!ent $ilot o$erated s&ste! • -ingle ele!ent self o$erated s&ste! • To ele!ent $ilot o$erated s&ste! • Three ele!ent $ilot o$erated s&ste!

65. "%at i* t%e +'r+o*e o& a'to$ati) )o$9'*tion )ontrol

The !ain $ur$ose auto!atic co!%ustion control s&ste! is to !aintain load ad,ust de!and" to $re'ent s!o(e" to increase %oiler house efficienc&" to carr& out routine ad,ust!ents and to $ro'ide interloc(ing safe guards.

6 "%at i* t%e '*e o& air +re%eater

Air $re heater is used to transfer heat fro! the flue gases to the air %efore it $asses into the furnace for co!%ustion. It is $laced %eteen the econo!i)er and chi!ne&. The o'erall efficienc& of the $lant !a& %e increased %& *7 $er cent %& the use of air $reheater.

63. "rite a9o't 9oiler $o'nting*

The de'ices used for the efficient o$eration" $ro$er !aintenance" and safe o$eration %oiler !ountings.

The different %oiler !ountings are

*. >ater gauge ;or< ater le'el indicator  3. ressure gauge ;or< stea! gauge

:. -afet& 'al'es ?. Fusi%le $lug 6. -to$ 'al'e . Blo off coc(  . Feed chec( 'al'e.

66. "%at i* $eant 94 9oiler trial

-tea! is generated in %oilers under certain conditions of feed ater and e+ists as stea! hile a certain a!ount of fuel is %urnt. To stud& the $erfor!ance of %oiler" so!e e+$eri!ents are conducted %& o$erating" the %oiler for a certain length of ti!e and recording the data. This  $rocedure is (non as %oiler trial.

67. State t%e o9(e)ti1e o& 9oiler trial

*.To deter!ine the ther!al efficienc& of the %oiler hen or(ing at a definite $ressure. 3.To dra u$ heat %alance sheet for the %oiler to chec( the $erfor!ance of the %oiler.

7:. !e&ine ,e$an, &a)tor

• De!and factor is defined as the ratio of !a+i!u! de!and to connected load.

• Connected load is the su! of ratings in (> of e0ui$!ent installed in the consu!er=s  $re!ises.

• Ma+i!u! de!and is the !a+i!u! load" hich a consu!er uses at an& ti!e. 7#. !e&ine loa, )'r1e

2oad cur'e is a gra$hical re$resentation %eteen load in (> and ti!e in hours. It. shos 'ariatin of load at the $oer station. The area under the load cur'e #re$resents the energ& generated in a $articular $eriod.

72. !e&ine loa, &a)tor

2oad factor is defined as the ratio of a'erage load to the $ea( load ;or< !a+i!u! de!and. 7. "%at in)l',e* &i;e, )o*t

Fi+ed cost includes the folloing cost.

*. Cost of land 3. Cost of %uilding :. Cost of e0ui$!ent ?. Cost of installatin 6. Interest . De$reciation cost . Insurance 9. Manage!ent cost 7/. "%at in)l',e* o+erating )o*t

O$erating cost includes the folloing cost.

*. Cost of fuel 3. Cost of o$erating la%our" :. Cost of !aintenance la%ours and !aterials.

?. Cost of su$$lier li(e

>ater for feeding %oilers" for condenser and for general use. 2u%rication oil and" grease.

>ater treat!ent che!icals. 75. "%at i* t%e nee, o& ,e+re)iation )o*t

De$reciation cost is the a!ount to %e set aside $er &ear fro! the inco!e of the $lant to !eet the de$reciation caused %& the age of ser'ice" ear and tear of the !achiner& and e0ui$!ents. De$reciation a!ount collected e'er& &ear hel$s in re$lacing and re$airing the e0ui$!ent.

7. "rite a9o't ato$i) n'$9er

The nucleus contains $rotons and neutrons. The nu!%er of $rotons in a gi'en ato! is an ato!ic nu!%er ;<. The ato!ic nu!%er for 1 is * and 1e #is 3.

73. "rite a9o't i*oto+e* o& an ele$ent

-o!e ele!ents ha'e the sa!e nu!%er of $rotons in the nucleus %ut different nu!%er# of neutrons. As a result" these ele!ents ha'e the sa!e ato!ic nu!%er %ut different !ass nu!%er. -uch t&$e of ele!ents hich = ha'e the sa!e ato!ic nu!%er H sa!e nu!%er of $rotons # the #sa!e che!ical $ro$erties %ut different !ass nu!%ers due to different nu!%er of neutrons" are (non as I the isoto$es of an ele!ent.

76. "%at are t%e re>'ire$ent* to *'*tain &i**ion +ro)e**

• The %o!%arded neutrons !ust ha'e sufficient energ& to cause fission • The nu!%er of neutrons $roduced !ust %e a%le to create the rate of fission • The fission $rocess !ust generate energ&

• The fission $rocess !ust %e controlled

77. !e&ine $'lti+li)ation &a)tor o& a &i**ion +ro)e**.

nu!%er of neutrons of an& one generation ( 

nu!%er of neutrons of i!!ediatel& $receding generation. #::. !e&ine &ertile $aterial* an, 9ree,ing in rea)tor*

There are !aterials li(e @3:6 _{and Th}3:3 _{hich are not fissile %ut can %e con'erted into} fissile !aterials %& the %o!%ard!ent of neutrons. -uch !aterials are (non as fertile !aterials.

The $rocess of con'erting !ore fertile !aterial into fissile !aterial in a reaction is (non as %reeding.

#:#. "%at are t%e ,e*ira9le +ro+ertie* o& a goo, $o,erator

• It !ust %e as light as $ossi%leIt !ust slodon the neutron as 0uic( as $ossi%le • It !ust ha'e resistance to corrosion

• It !ust ha'e good !achina%ilit&

• It !ust ha'e good conducti'it& and high !elting $oint

#:2. "%at are t%e ,e*ira9le +ro+ertie* o& a )oolant

• It should not a%sor% neutron

• 1a'e high che!ical and radiation sta%ilit& •  Non#corrosi'e

• 1a'e high %oiling $oint •  Non#to+ic

#:. Na$e &ew t4+e* o& rea)tor*.

Fast reactors" Ther!al reactors" natural fuel reactors" Enriched @raniu! reactors" ater !oderated reactors" hea'& ater !oderated reactor" gra$hite !oderated reactor" gas cooled reactors and -odiu! cooled reactors.

#:/. "%at are t%e a,1antage* '*ing CO2a* )oolant

• Gases do not react che!icall& ith the structural !aterials • Gas can attain an& te!$erature for a $articular $ressure • The& do not a%sor% neutron

• The lea(age of gas ill not affect the reacti'it& • The gas coolant $ro'ides %est neutron econo!&

#:5. "%at are t%e a,1antage* o& 9ree,er rea)tor*

• It gi'es high $oer densit& than an& other reactor  • 1igh %reeding is $ossi%le

• 1igh %urn#u$ of fuel is achie'a%le

• The o$eration of the reactor is not li!ited %& Xe $oisoning

#:. "%at are t%e ,e$erit* o& 9ree,er rea)tor

• 1ighl& enriched fuel is re0uired • Control is difficult and e+$ensi'e

• -afet& !ust %e $ro'ided against !elt don • 1andling of sodiu! is a !a,or $ro%le!

#:3. "%at are t%e a,1antage* o& So,i'$ in &a*t-9ree,er rea)tor*

• -odiu! has 'er& lo a%sor$tion cross#sectional area

• It $osses good heat transfer $ro$erties at high te!$erature and lo $ressure • It does not react ith an& of the structural !aterials used in $ri!ar& circuits

#:6. Na$e t%e ,i&&erent t4+e* o& MH! generator*

• O$en c&cle M1D • Closed c&cle M1D

• Closed c&cle M1D ith li0uid !etal

#:7. "%at i* t%e woring +rin)i+le o& $agneto %4,ro,4na$i) +ower +lant

The or(ing $rinci$le of M1D is as li(e that of d&na!o. Instead of solid conductor high te!$erature $las!a is $assed through the !agnetic field at sonic s$eed. >hen the gas is  $assed through !agnetic field" current is induced. Electrodes collect this induced current.

##:. "%at i* t%e +'r+o*e o& )ontrol ro,*

The control rods are used to start the chain reaction" !aintain the chain reaction at re0uired le'el and to shut don the reactor during e!ergenc&.

###. "%at are t%e ,i&&erent t4+e* o& loa, a)ting on t%e )%i$ne4

• Its on eight hich is considered to act on a single 'ertical force acting through the

centroid

• The ind $ressure" hich is considered to act on the hori)ontal force acting on the

centroid of 'ertical $ro,ected area.

##2. "%at i* $eant 94 N')lear &i**ion

@raniu! e+ists in different isoto$es of @3:9" t:? and @3:6. Out of these" E:6 is !ost unsta%le. >hen unsta%le hea'& nucleus is %o!%arded ith high#energ& neutrons" it s$lits u$ roughl& into to e0ual frag!ents and a%out 3.6 neutrons are released and a large a!ount of energ& is $roduced. This $rocess is called nuclear fission.

##. Na$e t%e ,i&&erent )o$+onent* o& n')lear rea)tor

*. Nuclear fuel 3. Moderator :. Control rods ?. Reflectors 6. Reactor 'essel . Biological shielding . Coolant

##/. State *o$e a,1antage* o& Pre**'riBe, "ater rea)tor • The $ressuri)ed ater reactor is co!$act

• In this t&$e" ater is used as coolant" !oderator and reflector ater is chea$ and a'aila%le in $lent&<

• It re0uires less nu!%er of control rods.

##5. "%at are t%e a,1antage* o& ga* )oole, rea)tor n')lear +ower +lant

*. Fuel $rocessing is si!$le

3. The use of C73 as coolant co!$letel& eli!inates the $ossi%ilit& of e+$losion in reactor. :. No corrosion $ro%le!

##. "%at i* 9ree,ing in n')lear rea)tor

The $rocess of $roducing fissiona%le !aterial fro! a fertile !aterial such as uraniu! 3:9 ;@3:9< and thoriu! 3:3 ;Th 3:3 < %& neutron a%sor$tion is (non as %reeding.

##3. Na$e t%e )oolant* )o$$onl4 '*e, &or &a*t 9ree,er rea)tor* 2i0uid !etal ;Na ;or< Na /<

1eliu! ;1e< Car%on dio+ide.