boiler efficiency 3hriwhel `

8/11/2019 Boiler Efficiency 3hriwhel `

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At M/S JINDAL STEEL &POWER LIMITED

KHARSIA ROAD

RAIGARH(C.G.) PIN 496001

Project submitted by :-Suhail ahmad mansoori

Students of 7th Semester of B.E. in MECHA!CA" E#!EE$!#

#.H.$A!S%! C%""E#E %& E#!EE$!#C$P& #A'E %.() H!#A $%A*)A#P+$-,

(An autonomous institute under the UGC act 1956)

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I think I have accomplished what I set out to do.

Im thankful to those persons who havecontributed a great amount of time, talent andeort to make this project an utter success.

Im grateful to for their overwhelming supportthat has been rendered to us in due course ofour project.

Im also grateful to my parents, who have beenalways a great support for us. Not to mentionabout the blessings of almighty God, while weare amidst to our project.

y thanks and appreciation goes to all those

people who are directly or indirectly associatedwith this project.

-S!"#$ A!%" M"'*#

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Certicate of 'rainin/

This is to certify that

student Mr. / Ms Suhail Ahmad Mansoori

of G.H. Raisoni College of Engineering

has undergone training in our companyfrom -!/"/#!!to -#/"/#!!.His

conduct during the training $as good.

D"t+,

S#'"t*+

P$"+,

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Contents

Preface

%r/ani0ational %1er1ie2

Boiler e3ciency

!ntroduction

'he Measurement of Boiler E3ciency: Standards

!he "irect ethod

o #eat Inputo #eat $utput

!he Indirect ethod

'y4es of "osses

"ry %lue Gas &oss

&oss due to 'vaporation of #($ formed

due to #(in %uel

&oss due to oisture present in %uel

&oss due to oisture present in )ir

&oss due to Incomplete *ombustion

+adiation *onvection &oss

&oss due to -nburnt %ly )sh

&oss due to -nburnt ottom )sh

Calculations

Input /heet

*alculation /heet

$utput /heet

Conclusion

Coolin/ to2er e3ciency

!ntroduction

Calculations

Conclusion

Biblio/ra4hy

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%RE&ACE

!'$%*+C'!%

A boiler is an enclosed 'essel that pro'ides a means for com(ustionheat to (e transferred into $ater until it (ecomes heated $ater orsteam. The hot $ater or steam under pressure is then usa(le fortransferring the heat to a process. )ater is a useful and cheapmedium for transferring heat to a process. )hen $ater is (oiled intosteam its 'olume increases a(out !*" times* producing a force thatis almost as e+plosi'e as gunpo$der. This causes the (oiler to (ee+tremely dangerous e,uipment that must (e treated $ith utmost

care. The process of heating a li,uid until it reaches its gaseous stateis called e'aporation. Heat is transferred from one (ody to another (ymeans of ! radiation* $hich is the transfer of heat from a hot (ody toa cold (ody $ithout a con'eying medium* # con'ection* the transferof heat (y a con'eying medium* such as air or $ater and conduction* transfer of heat (y actual physical contact* molecule tomolecule.

The heating surface is any part of the (oiler metal that has hotgases of com(ustion on one side and $ater on the other. Any part of

the (oiler metal that actually contri(utes to ma0ing steam is heatingsurface. The amount of heating surface of a (oiler is e+pressed ins,uare meters. The larger the heating surface a (oiler has* the more

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e1cient it (ecomes. The ,uantity of the steam produced is indicatedin tons of $ater e'aporated to steam per hour.

A (oiler is an important part of any thermal po$er plant. The(oiler used in the5ojobera Po2er Plantis the $ater tu(e (oiler. The

2o3o(era %lant $or0s on the modi4ed form of the $an6ine Cycle.

5oiling and su(se,uent steam generation is the (asic function of the(oiler. The proper functioning of the (oiler is possi(le $ith the help ofa furnace* (oiler drum* $ater $alls* super heaters* reheater*economiser* do$n comers* draft system 6 necessary control 'al'es.Steam generator is radiant reheat* $et (ottom* natural circulation*single drum* direct corner 4red* tilting (urners* (alanced draft* topsupported type (oiler.

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Boiler Phase Capacityin TPH

Year ofCommissioning

1. AFBC-1 Ph-1 165 2

2. AFBC-2 165 2

!. AFBC-! Ph-2 165 2"

". AFBC-" 165 2"

5. #H$B-1 Ph-! 5% 25

6. #H$B-2 5% 25

%. #H$B-! 5% 25

&. #H$B-" 5% 25

5S

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5SP" P%E$ P"A'

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The role of e1ciency monitoring lies in ma+imi7inggeneration from the thermal po$er plants. 8t enhances energye1ciency of the po$er plant. 8n order to 0eep ma+imum output from agi'en input* the units must run at the ma+imum possi(le e1ciency.

%o$er plant performance at 'arious steps helps in impro'ing thepo$er generation capacity.

8t is usual for the 5oiler manufacturer to pro'e to the purchaserthat the 5oiler* after commissioning* can achie'e its rated output andstated e1ciency9 this is an :acceptance; test and is carried out 'eryformally as legal matters may (e in'ol'ed if the 5oiler does not meet*$ithin stated limits* its guaranteed output and e1ciency.


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&) 'oss due to un"urnt fy ash.() 'oss due to un"urnt "ottom ash.

The e1ciency of a (oiler can therefore (e e+pressed alternati'elyas !? minus the sum of the losses e+pressed as a percentage ofthe input energy.

'HE MEAS+$EME' %& B%!"E$E&&!C!EC8 : S'A*A$*S

The t$o de4nitions of e1ciency gi'en a(o'e lead to t$o methodsof measuring it

! 5y measuring input and output this is called the D"irectethod

# 5y measuring indi'idual losses* totaling them and deducting thesum from !?. this is called the DIndirect ethod* (ut theterms :losses method; and :e!ien!y "y di*eren!e; are alsoused

8deally* (oth methods should (e used* one as a chec0 upon theother* and a complete heat (alance o(tained. There $ill (e adi>erence (et$een the results o(tained from each* this di>erence(eing due to human and instrumental errors. Testing (y (oth methodsis rarely done* ho$e'er* the costs of doing so (eing prohi(iti'ecompared $ith the (ene4ts o(tained. Ha'ing o(tained t$o 'alues fore1ciency* the ,uestion $ould arise $hich one should (e accepted incase of dispute.

8t is no$ generally accepted that the indirect method is thesimpler to carry out and yields the more accurate results. 8t alsoidenti4es the loss areas $hich need attention should a shortfall ine1ciency (elo$ the e+pected 'alue occur. The reason for greateraccuracy of the indirect method is really ,uite simple. )hereas thedirect method needs to measure the output* $hich is around @? ofthe input* the indirect method only measures #? of the input. A !?error in the direct method therefore gi'es an error of .@ e1ciencypoints* $hereas a similar error in the indirect method only gi'es anerror of .# e1ciency points. The full analysis of the pro(a(ility oferrors occurring is much more comple+ than this* (ut the (asicprinciple is similar.

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)here thermal testing is conducted for contractual purposes* it isessential that the agreed standard (e implemented rigorously andproperly $itnessed9 $here routine tests are in'ol'ed the re,uirementsare less stringent (ut in his o$n interests the (oiler user is ad'ised toensure that accurate instruments in good $or0ing conditions are usedin accordance $ith the method descri(ed in the Standards.

THE F8RECT METH


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factors* together $ith the 0no$n $idth of the grate* ena(le the'olume of the coal used to (e continuously calculated (y amicroprocessor. The fuel (ul0 density is input to the microprocessorusing information o(tained from measurements of the density ofsamples ta0en at inter'als. The microprocessor can then indicate andrecord the ongoing fuel consumption in suita(le units.

Heat output-

There are se'eral methods $hich can (e used for measuring heatoutput. )ith steam (oilers* an installed steam meter can (e used tomeasure =o$ rate* (ut this must (e correct for temperature andpressure. 8n earlier years* this approach $as not fa'oured due to thechange in accuracy of ori4ce or 'enturi meters $ith =o$ rate. 8t is no$more 'ia(le $ith modern =o$ meters of the 'aria(le- ori4ce or 'orte+-shedding types. 8t is not usually easy to install a meter specially for atest* as (ends in pipes can a>ect its accuracy. The alternati'e $ithsmall (oilers is to measure feed $ater* and this can (e done (ypre'iously cali(rating the feed tan0 using $eighed increments of$ater to 4ll the tan0 from a mar0ed lo$ le'el to a mar0ed high le'el*and operating the tan0 (et$een these limits. The num(ers of 4lls arecounted and* 4nally* the intermediate position is interpolated $henthe test ends. )here feed$ater is measured* ho$e'er* it is important

to allo$ for (oiler (lo$do$n and* $ith saturated steam (oilers* steam$etness. ormally* this latter should not e+ceed a(out #? of theoutput* (ut it can (e much more than this if $ater conditions are lia(leto cause foaming.

)ith hot-$ater (oilers the heat output is measured (y aninstalled $ater meter* prefera(ly of the 'aria(le-ori4ce tan0. Thetemperatures of the $ater entering and lea'ing the (oiler are alsore,uired. )ith lo$ temperature hot-$ater systems* of $hich there aremany* the di>erence (et$een =o$ and return $ater temperatures can

(e as little as #C*in $hich case an error of only !C in themeasurement of this di>erential is e,ui'alent to an error of I? in themeasurement of heat output.

According to this method the 5oiler e1ciency is e+pressed as*

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)dvantages of direct method1 %lant people can e'aluate ,uic0ly the e1ciency of (oilers. Re,uires fe$ parameters for computation. eeds fe$ instruments for monitoring.

"isadvantages of direct method1 Foes not gi'e clues to the operator as to $hy e1ciency of

system is lo$er Foes not calculate 'arious losses accounta(le for 'arious

e1ciency le'els

THE 8F8RECT METH


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5) n!omplete !om"ustion.#) $adiation and %onve!tion losses.&) 'oss due to un"urnt fy ash.() 'oss due to un"urnt "ottom ash.

,= *ry >ue /as loss :?

This is the heat loss from the (oiler in the dry component of gases to

the stac0. This loss in a typical e+ample can (e of the order of J.I?.

'he *ry &lue #as "oss *e4ends +4on '2o &actors-!. ENCESS A8R#. A8R HEATER


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The heat lost to the =ue gases depends upon the ,uantity ofproducts of com(ustion and the temperature of the gas lea'ing theheat reco'ery e,uipment. The ,uantity of e+cess air to (e employedto ensure complete and satisfactory com(ustion is determined from0no$ledge of the com(ustion characteristics of the fuel and the typeof com(ustion e,uipment to (e used9 pre'ious e+perience plays an

important role in this. Typical 'alues for industrial $ater tu(e (oilers$here 'aria(le loads are e+perienced are

atural gas !?

Hea'y fuel oil !?

Coal* sto0er 4red I-J?

Oo$er 'alues can (e used* (ut they re,uire good maintenance andoperation on the 4ring e,uipment for them to (e sustained. )hen

selecting the =ue gas temperature that is to (e achie'ed* the follo$ingfactors must (e considered.

5oiler a'aila(ility* i.e. the percentage of the annual $or0ing

hours for $hich the (oiler is a'aila(le for use.

&uel costs

Type and composition of fuel

&eed$ater temperature a'aila(le

The e>ects of these are interrelated to some e+tent. &or instance*

a (oiler gi'ing high thermal e1ciency does not necessarily gi'e a higha'aila(ility if a lo$ =ue gas temperature is used $hich results in rapidfouling of the heat reco'ery e,uipment.

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Oo$-temperature corrosion has a signi4cant in=uence upon thechoice of 4nal gas temperature $hen heat reco'ery e,uipment isincluded. A com(ination of a gas outlet and cold =uid inlettemperatures must (e selected to gi'e the desired minimum tu(esurface temperature $ithin the heat-reco'ery e,uipment.

8f lo$-temperature corrosion is to (e a'oided and a long life is

desired for the heat-reco'ery e,uipment* it is recommended that the=ue gas temperature should (e less than !@C for sulphur (earingoils and !"C for sulphur (earing coals. )hen using economisers it israrely economical to reduce the =ue gas temperature to a 'alue lessthan C a(o'e the inlet temperature of the feed $ater.

The e+pression used to calculate dry =ue gas loss is as follo$s

*ry &lue #as "oss @


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H# P percentage of hydrogen in fuel


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speci4c heat capacity of superheated steam.The e+pression used to calculate loss due to moisture present in fuel isas follo$s

)here* M P percentage of moisture in fuel CpP speci4c heat capacity of superheated steam Tf P temperature of =ue gas at air pre-heater outlet Ta P am(ient temperature

= "oss due to Moisture 4resent in Air :?

This is the loss of heat from the (oiler in the =ue gases due to$ater 'apour $hich $as present initially as moisture in the actual airsupplied for com(ustion of fuel. This loss cannot (e ignored as the airsupplied (y %A and &F fan* e'en after getting heated in the air pre-heater still has certain amount of moisture contained in it $hichaccounts for this type of loss. Thus it can (e said that this type of lossdepends upon the humidity factor of the supplied air.

The e+pression used to calculate loss due to moisture present in air isas follo$s

)here* CpP speci4c heat capacity of superheated steam TfP temperature of =ue gas at air pre-heater outlet TaP am(ient temperature

= "oss due to !ncom4lete Combustion :?

This is (ecause of incomplete com(ustion of car(on* i.e. C to Cect $ill 'ary $ith (oiler si7e* fuel and 4nal gastemperature. The trend $ill (e for the e1ciency to fall $ith reducingload* $ith small units due to the relati'ely high radiation loss* $hereas$ith large (oilers the e1ciency may pea0 at a load (elo$ !?ma+imum continuous rating MCR.

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5i(liography

8FLSTR8AO 5

boiler efficiency 3hriwhel `

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