energy assesment of boiler

8/9/2019 Energy Assesment of Boiler

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Performance Terms and Definitions

Heat ot!t

Heat In!tBoiler Efficiency, =

Heat in steam ot!t "#Ca$s%Heat in Fe$ In!t "#Ca$s%

&antit' of Steam Generation

Quantity of fuel ConsumptionEvaporation Ratio =

The efficiency of a boiler is expressed as the % of useful heat

available from the total energy available by burning the fuel.

T(is is e)!ressed on t(e *asis of +ross ca$orific ,a$e "GC-% .


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StandardsBritis( standards/ BS0123 4506

This describes the methods and conditions under which a boilershould be tested.Boiler should be operated under steady load

conditions generally full load! for a period of one hour before ta"ing

reading

ASME Standard3 PTC7174 Po8er Test Code for Steam Generatin+

9nits

Part One: Direct method (also called as Input -output method) Part Two: Indirect method (also called as Heat loss method)

IS 062:3 Indian Standard for Boi$er Efficienc' Testin+

#ll standards do not include blow down as a loss in the efficiency

determination process.


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Direct Met(od Testin+

$

valuecalorific&rossxratefiring'uel

enthalpy!waterfeedenthalpysteamxrateflow(teamxEfficiencyBoiler

=


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Indirect Met(od Testin+

Boi$er 'lue gas sample

(team )utput

Efficiency = $ * $++-++/+0+1+2! by 3ndirect 4ethod!

#ir

'uel 3nput, $%

$. 5ry 'lue gas loss

. 6 loss

-. 4oisture in fuel

. 4oisture in air

/. 7) loss

1. 'ly ash loss

0. (urface loss

2. Bottom ash loss

Blow down


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Instruments used for Boiler PerformanceAssessment.

Instrument Type Measurements

Flue gasanalyzer

Portale or !i"ed # $O% & O% and $O

Temperatureindicator

Thermocouple&li'uid in glass

Fuel temperature& !lue gastemperature& comustionair temperature& oilersur!ace temperature&steam temperature

Dra!t gauge anometer&di!!erentialpressure

mount o! dra!t used ora*ailale

TD+ meter $onducti*ity ,oiler water TD+& !eedwater TD+& mae-up waterTD+.

Flow meter s applicale +team !low& water !low&!uel !low& air !low


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4.Tec(nica$ s!ecification of *oi$er

/ ,oiler ID code and ae

% 0ear o! ae

1 ,oiler capacity rating

2 Type o! ,oiler

3 Type o! !uel used

4 a"imum !uel !low rate

5 6!!iciency y 7$8

9 +team generation pressure superheat temperature

; Heat trans!er area in m%

/< Is there any waste heat reco*ery de*ice installed

// Type o! dra!t

/% $himney height in metre


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; 7 Fe$ ana$'sis detai$s

Fe$ Fired

GC- of fe$

S!ecific +ra,it' of fe$ "Li


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9$timate Ana$'sis Date of Test3$aron #

Hydrogen #

+ulphur #

=itrogen #sh #

oisture #

O"ygen #

Water Analysis Date of Test:Feed water TD+ ppm

,low down TD+ ppm

PH o! !eed water

PH o! low down

Flue gas Analysis Date of Test:

$O%

#

O%

#

$O #

Flue gas temperature O

$


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S

.No

T

ime

Amient air Fuel Feed !ater Steam Flue gas

analysis

Surface

Temp ofoiler" o# Dry

ulTemp"

o#

WetBul

Temp"o#

Flo!$ate"%g&'r

Tempo

#

Flo!rate"

m(&'r

Tempo

#

Flo!

rate"

m(&'r

Pr

ess

r

e%g&c

m)

g

Tempo

#

*

)

+

#*

)

+

C

O

+

Temp,

#

/.

%.

1.

2.

3.

4.

5.

9.

-. Format s'eet for oiler efficiency testing

5ate8 9999999 Boiler 7ode :o. 9999999

Boiler (upervisor Energy 4anager Energy #uditor


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'uel firing rate = //;;.$1 "g of fly ash = /./ "7al of 7oal = -/$ "7al


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Boi$er efficienc' *' indirect met(od

Ste! > 4 Find t(eoretica$ air

re


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Ste! > ; Find t(eoretica$ CO;=

7)at theoretical condition 7)!t

=

4oles of 7

4oles of :+ 4oles of 7

here,

oles of : =

.2 x 11


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Ste! > : To find E)cess air

s!!$ied

#ctual 7) measured in flue gas = $.%

% Excess air supplied E#! = 1; x @ 7)!t* 7)!aC

7)!ax @$ * 7)!tC

= 1; x @.01 * $ C

$ax @$ * .01C

= 16.11 =


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Ste! > 1 to find acta$ mass of air s!!$ied

#ctual mass of air supplied = A$ + E#


16/22

Ste! > @ to find a$$ $osses

$. % 6eat loss in dry flue gas $! = m x cpx Tf* Ta!

x $

&7> of fuel

=1./0 x .- x $; * -$!

x $-/$

$ = 6.05 =


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. % 6eat loss due to formation

of water from 6in fuel !

= ; x 6 x A/2 + 7pTf* Ta!

x $

&7> of fuel

=; x .$ x A/2 + ./$;D-$!

x $

-/$ = :.11 =

-. % 6eat loss due to moisture in

fuel E-!

=

4 x A/2 + 7p Tf* Ta!

F $

&7> of fuel

=

.-$0 x A/2 + ./ $; * -$!

x $

-/$

E- = 2.54 =


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. % 6eat loss due to moisture in

air !

=

##( x humidity x 7px Tf* Ta! x $

&7> of fuel

=1.$- x . x ./ x $; * -$! x $

-/$

= .;5 =

/. % 6eat loss due to partial

conversion of 7 to 7) /!

=%7) x %7 /1

x x $

% 7) + % 7)!a &7> of fuel

=

.// x .$0/ /1

x x $.// + $ -/$

/ = ;.20 =


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0. 6eat loss due to radiation and

convection E0!

= ./2 x @ --


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1. % 6eat loss due to unburnt in fly ash

#sh in coal = 2.0-

atio of bottom ash to fly ash = ;8$&7> of fly ash = /./ "7al


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oiler efficiency by indirect

ethod

= $ * E$+ E+ E-+ E+ E/+ E0+ E1+ E2!

= $D1.2; + -.+ /.;$+ .;+ ./2+ ./+

.$$+$.11!

= $D.

66.6@ =

Summary of Heat Balance for Coal Fired Boiler

In!t?Ot!t Parameter #Ca$ ? #+ of

coa$

= $oss

6eat 3nput = -/$ $Eosses in boiler

$. 5ry flue gas, E$ = 10.- 1.2;

. Eoss due to hydrogen in fuel, E = $.- -.

-. Eoss due to moisture in fuel, E- = 0.;$ /.;$

. Eoss due to moisture in air, E = $.$/ .;

/. Gartial combustion of 7 to 7), E/ = ;.- ./20. (urface heat losses, E0 = 2.1/ ./

1. Eoss due to Hnburnt in fly ash, E1 = -.2/ .$$

2. Eoss due to Hnburnt in bottom ash,

E2

= 0$.;1 $.11

Boi$er Efficienc'= $ * E$+ E+ E-+ E+ E/+ E0+ E1+ E2% 66.6@ =


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Factors Affecting BoilerPerformance

I Geriodical cleaning of boilers

I Geriodical soot blowing

I Groper water treatment programme and blow down

control

I 5raft control

I Excess air control

I Gercentage loading of boiler

I (team generation pressure and temperature

I Boiler insulation

I Juality of fuel

energy assesment of boiler

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