Plant Emissions Reduction Pgm

7/25/2019 Plant Emissions Reduction Pgm

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by Nathan Long

Muskingum River PlantMuskingum River Plant

Emissions ReductionEmissions Reduction

Programs Programs



2 2

Precipitators Precipitators

Ohio Environmental Protection Agency (EPA) dictates opacity must bebelow 20! Other states may have di""erent regulations!

#nits $%&

Each unit has a 'oyestern precipitator!

*onsists o" $+ "ields powered by , trans"ormerrecti"iers!

Neundor"er voltage and rapper controls!Opacity averages between -%$2

#nit -

.esearch *ottrell / two boes!

Each bo has 10 recti"ied "ields!

Neundor"er voltage and rapper controls

Opacity averages approimately -!



3 3

Precipitator Problems Precipitator Problems

#nits $%&

*asing leas allows moisture to enter precipitator creating high levels o"

sparing thus driving power levels down!

3rans"ormerrecti"iers "ailing more "re4uently than in the past!

.eaching end o" li"e5

Neundor"er controls aggresively ramp voltage bac up "ollowing spar

4uenching which may be shortening li"e o" trans"ormerrecti"iers!

Electrodes were "ailing causing grounds! .esolved by installing a heavier

gauge electrode wire!

Precipitators are undersi6ed so any upsets o"ten cause load curtailments to

stay under 20 opacity!

#nit -

Precipitators are oversi6ed! No real problems!



4 4

Sulfur Trioxide (SO3) and Sulfur Trioxide (SO3) and mmonia (!"3)mmonia (!"3)

#lue $as %onditioning S&stem #lue $as %onditioning S&stem

#sed on units $%& (subcritical units)

7ecreases "lyash resistivity to improve collection o" ash in precipitators!

Advantageous when sul"ur content o" coal drops below 1!- lbs8btu!

9O1 system

8olten sul"ur stored in $00 ton tan (appro! +0 day capacity) at $&1 deg! * (2:0 deg!

;)!

9ul"ur pumped through steam <aceted lines to sul"ur burners!

9ul"ur gas passes through vanadium pentoide catalyst which accelerates the

natural process o" the chemical reaction to ensure at least :- o" the sul"ur dioide

is converted to sul"ure trioide!

$- w (20 =P)> 1+00 rpm process air blower / $- cmmin (-10 sc"m)

2!2 w (1 =P)> 1+00 rpm purge blower eeps piping and no66les clear when system is

out o" service!

+ in<ection probes distribute the 9O1 into the duct upstream o" precipitator!



5 5

Sulfur Trioxide (SO3) and Sulfur Trioxide (SO3) and mmonia (!"3)mmonia (!"3)

#lue $as %onditioning S&stem #lue $as %onditioning S&stem

N=1 9ystem

#sed with 9O1 system to enhance ?collectibility@ o" the ash!

Anhydrous ammonia stored as a pressuri6ed li4uid in a bul storage tan!

3an e4uipped with 2 / $0 w heaters which vapori6es the ammonia!

Ammonia vapor passes through a regulating valve ($%- ppm) be"ore being

in<ected through + probes!



6 6

Sulfur Trioxide (SO3) and mmonia (!"3)Sulfur Trioxide (SO3) and mmonia (!"3)

Problems Problems

9ul"ur 3rioide

8ust maintain proper insulation on steam <aceted sul"ur lines or sul"ur will

solid"y! Eperienced this on startups> had to heat lines with torches to get

sul"ur to "low! mproved insulation too care o" the problem!

3he sul"ur metering pumps are a submersible gear type pump with very

close tolerances! 3he pumps wear and eventually will not pump at which

time they have to be replaced and sent out "or re"urbishment! 3hey cannotbe repaired on site!

hen the system is shut down> the purge air blower must be in service or

"lue gas will come bac into the lines and plug the probes!

3he probes are buly and heavy and must be removed to be unplugged!



7 7

Sulfur Trioxide (SO3) and mmonia (!"3)Sulfur Trioxide (SO3) and mmonia (!"3)

Problems Problems

Ammonia (N=1)*are must be taen not to over in<ect or it will "oul the precipitator!

Ammonia detection systems and alarms must be maintained around

the storage tan and in<ection sids to alert personnel o" any leas!



8 8

%ontinuous Emissions Monitoring S&stem%ontinuous Emissions Monitoring S&stem

(%EMS) (%EMS)

All "ive units e4uipped with a redundant continuous emissions monitoringsystem!

8onitorsB

Opacity

9ul"ur 7ioide (9O2)

Nitrous Oide (NO)

*arbon 7ioide (*O2)

;lue gas sample is diluted with air 100B$ to etend li"e o" instrumentation andmae the system more reliable!

8onitors analy6e the gas sample and send raw data to a polling computer whichcalculates mass emissions rates!

3he *E89 technician per"orms daily checs o" the data be"ore sending on to AEP> *olumbus! 3he data is submitted to the Ohio Environmental Protection

Agency on a 4uarterly basis!Preventive maintenance is per"ormed on the e4uipment on a 4uarterly basis!

8onitors automatically calibrate daily!



9 9

!ox Reduction $oals !ox Reduction $oals

#nits $% 2 8aintain NO Emission .ate under

CC: gcal (0!&& lbmbtu)

#nits 1%& 8aintain No Emission .ate under

&++ gcal (0!10, lbmbtu)#nit - 8aintain NO Emission .ate under

$0$ gcal (0!0+C lbmbtu) with 9*.



10 10

Terminolog& Terminolog&

3heoretical air is the minimum air re4uired

"or complete combustion o" the "uel>

resulting in stoichiometric combustion! 9toichiometry (also called stoichiometric

ratio) is a term relating the actual air to the

theoretical minimum air re4uired to complete

combustion!



11 11

Terminolog& Terminolog&

Excess air is the amount of air supplied for combustion

in "excess" of that theoretically required for complete

combustion.

This additional air is required because of imperfectionsassociated with the combustion process and the

practical limitation of providing the Three T's of

Combustion.



12 12

Overfire ir Overfire ir

zone

zone !overfire air

fuelair mixture

in the overfire air to complete the

combustion process.

zone !# $ring in %&!% of total air

combustion air to burn fuel under

less than stoichiometric conditions.

zone # $ring in (%&)% of total

fuelair mixture

*econdary +urnace

,rimary +urnace

_______________________________________________________________________



13 13

How OFA System Reduces NOx U1&2

+uel&rich combustion zoneThe reducing environment helps control fuel and

thermal -xThe lower pea/ flame temperature helps further reduc

the formation of thermal -x verfire air zoneThermal -x formation is limited due to lower gas and

flame temperatures



14 14

How OFA System Reduces NOx

U3&4

+uel&rich zone0ithholding air causes the cyclones to be operated fuel&rich. 1s

a result2 C is produced within the cyclone. 3n the lower furnace

this C aggressively reduces already formed -x to -! in its

attempt to form C!.The lower pea/ flame temperature provides an additional

incremental reduction in -x. verfire air zone

Thermal -x formation is limited due to lower gas and flame

temperatures.



15 15

Business Confidential 28

Application of Overfire Air

Co!ustion "one #toic$ioetr%

1&00&85 1&15

O'idi(in)*educin)

+ O ' , o r a t i o n * a t e

C O -

i s s i o n s



16 16

1tmospheric -itrogen -x4!52 temp.

Thermal NOx Mecha!sm

Critical

Temperature



17 17

!on S%R !Ox Reduction Problems !on S%R !Ox Reduction Problems

.educing atmosphere causedB Accelerated tube wastage in primary "urnace

=ad to "ind acceptable stoichiometric setting to limit wastage

9evere erosionloss o" re"ractory on "urnace "loor! Large amounts

o" molten iron pooled on the "urnace "loor at a higher "re4uency!

9u""ered numerous tap throughs!9tarted with silicon carbide re"ractory! Eperimented with other "orms

o" re"ractory! =igh alumina> - chrome re"ractory seems to hold up

best!

9evere pluggage in convection pass! Added + electric sootblowers

to eep area clean!



18 18

Selective %atal&tic Reduction (S%R) Selective %atal&tic Reduction (S%R)

Degan operation in 8ay> 200-!Operates "rom 8ay $ through 9eptember 10!

ill be re4uired to operate year round beginning in 200:!

3here"ore> it was decided not to install bypass ducts and dampers!

3wo reactor boes (north and south)

9i6ed to hold "our layers o" catalyst! nitial operation is with two layers! 3hird layer is

to be installed in 9pring o" 200C! ;ourth layer is "or "uture use> perhaps "or mercuryremoval!

*atalyst supplied by =itachi America Ltd!

Plate type> titanium dioide (3iO2) carrier impregnated with tungsten trioide (O1)

and vanadium pentoide (2O-)!

C2 catalyst modules per layer (: wide F , deep grid)!

nitial guarantee is "or $+>000 hours o" :0 NO removal be"ore third layer is added!



19 19


3wo dra"t booster "ans were installed to overcome the new 9*. system pressure drop!

Located between the precipitator and the stac

=owden ?aria@ constant speed> single stage> hori6ontal> aial "low!

#tili6es variable pitch blades "or "low control! Dlades are hydraulically controlled!

mpeller diameter is 1!C meters ($&+ inches)!

Operates at ,:- rpm!

Ammonia vapor system

#rea brought in by truc

7issolved in water to a &0 by weight solution in a mi tan!

=eated to 2$0 deg * (&$0 deg ;) at 2,!$2 gscm (&00 psig) by steam in ahydrolysis reactor (hydroli6er)! 9team comes "rom high pressure turbineehaust!

Produces ammonia and carbon dioide!



20 20


Ammonia vapor system (continued)9pent solution (recycle G 1 solution) is continuosly withdrawn "rom the

hydroli6er> sent through an economi6er and then to a recycle storage tan!

t is then used in the mi tan to mi batches o" urea solution!

Haseous ammonia and carbon dioide leave the hyrdoli6er vessel and

"eeds a dilution sid upstream o" each catalyst bo! Each sid has an

ammonia "low control valve that meters the correct amount o" ammonia toachieve desired NO reduction!

3he rate o" ammonia generation in the hydroli6er is controlled to maintain

constant mani"old pressure at the dilution sids!

hen the ammonia vapor gets to the dilution sid> it is diluted and mied

with air "rom dilution air "ans! t is then in<ected into the duct through a grid

o" pipes upstream o" the catalyst!



21 21

Ammo!a"o"#emadTMAmmo!aAmmo!a""oo""#emad#emadTMTM

To

*C6

1mbien

1ir *team

7ry*torage

7emin 0ater

,reheater

M!x Ta$

Hydroly%er

Flash

Searator

'lo

Selective %atal&tic Reduction (S%R)Selective %atal&tic Reduction (S%R)



22 22

Selective %atal&tic Reduction (S%R)Selective %atal&tic Reduction (S%R)

Problems Problems

Large particle ash (LPA)Large particles o" ash carried through the ductwor settles out on the screensabove the catalyst! As it accumulates it blocs o"" the gas path and "iner ashthen builds up as well!

*reates a di""erential increase through the catalyst "rom G -0 gs4m (2 incheswater) to G :+!- gs4m (1!, inches o" water) at which time the unit has to bebrought o"" line "or cleaning o" the catalyst!

At :+!- gs4m (1!, inches o" water) di""erential> the catalyst chamber is -0bloced!

*reates a problem "or the booster "ans to maintain desired economi6er outlet pressure!

*urrently designing a hopper to install under the economi6er to catch thelarge ash be"ore it reaches the catalyst boes!

8ay incorporate a screen to catch and direct the ash to the hopper!

Plan to install hopper in 9pring o" 200C!

(2) M*+,-.*

1/002//( 13321 .M8.( lb"9btu-x

x!t +as Tem& M!!mum

3/1 #+ F

-x 8.(! lb"9btu

CE9 6ight

CE9 :ef t



23 23

Plant 'nformation (P') Screen Plant 'nformation (P') Screen

1/002//( 13321 .M

-orth *C6 6eactor

:ayer ;

:ayer

,recipitator

From coom!%er

$ooster +an

+as -let

(;<.=(

7E> +

+AS OUT4T

;8.);7E> +

-orth 1ir ?eater

!.)8

AH #!55,

3n. ?!8

:ayer !

NH3 -6ect!o

:ayer @

*outh *C6 6eactor

:ayer ;

:ayer

,recipitator

From coom!%er

$ooster +an

+as -let

(;!.@(

7E> +

+AS OUT4T

;8@.);7E> +

*outh 1ir ?eater

;.;=

AH #!55,

3n. ?!8

:ayer !

NH3 -6ect!o

:ayer @

%.<) 3n. ?!8

%.== 3n. ?!8

8.(

8.(!

lb"9btu-x

-x -x

-x

lb"9btu

8.== lb"9btu

8.=8 lb"9btu

( lb"hr

=8 +

8 psi

Ander 6angelb"hr

psi

=; +

!< 1mps

;( '

!(@ 1mps

@@ '

&;.);3n. ?!8 &=.=% 3n. ?!8

8.8 ).<' 6emoval ' 6emoval

(;<.<@

(;!.!8 7E> +

7E> +7E> +

(;!.=;

(;.@! 7E> +

*! lb"9btu2,33

&;.@8

&;.(%

&=.(@&=.<<

=.!)%.=8

.)<

*C6 7iff.

-orth

3n. ?!8

*outh

*C6 7iff.

!.;( 3n. ?!8

3/1 #+ F

-x Trends

8.

8

8.!3/,/) ,,9

Calc. *; :eaving *C6

-orth *outh

-orth*outh



24 24

#lue $as esulfuriation S&stem #lue $as esulfuriation S&stem

or has begun to build a "lue gas desul"uri6ation systemon unit -! Pro<ect has been postponed to an in service dateo" $21$20$0!

*hiyoda design "rom 'apan

7i""ers "rom the conventional spray tower scrubber in that it

uses a <et bubbling reactor which sparges the "lue gas into alime slurry bath where $00 o" the "lue gas reacts with thelime slurry be"ore bubbling o"" the top and leaving thereactor to the stac!

;oundations have been completed "or the reactor and a new

2-2 meter (,2+ "oot) high stac!



25 25

#lue $as esulfuriation S&stem #lue $as esulfuriation S&stem

7esigned to provide su""icient limestone slurry to absorb:, 9O2 "rom the "lue gas!

Allows the burning o" $$!1 mgm 9O1cal (C!- lb 9O28btu) coal

.edundant $00 ball mill systems capable o" grinding &0tons o" limestone per hour!

,:- w ($200 hp)> & motors> hori6ontal> wet> with steel grindingballs!

9*. booster "ans will be replaced with two =owden> -0capacity aial "ans> each rated at G $$!2 mw ($->000 hp)!

Hypsum will be produced at G C1 tonshour and will be

dewatered by one vacuum belt "ilter be"ore being land"illed!



%onceptual Model for Scrubber %onceptual Model for Scrubber

*et +ubbling*et +ubblingReactor Reactor T&pical Spra&T&pical Spra&

To,er To,er

Gas is sparged

into Liquid

Liquid is sprayed to

into Gas

.et Bu!!lin) /a%er

*eservoir

Plant Emissions Reduction Pgm

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