ALCOA

25 October 2010

Alcoa Pn=ry M'lills! A/coo Forglngs and Extrusions

Massena Opcrabonsl-\ht Planl

P"'* ~...,"" r."

Moutno,.I\'Y J3U2-<lISO us....

Mr. Chris lalone, PE.

:'\.'YSDEC - Region 6

Division of Air Resources

317 Washington Street

Watertown, 1'\..,,,, York 13601

RE: Alcoa Massena West Operations

BART and NOx RAG Assessment

RespollSl! to 1\'YSDECs Comments and Questions

[)(>ar Mr. lalone:

This correspondence is being submitted by Alcoa Massena West Operations (Alcoa) in respolt5e

to comments regarding the Alcoa Best Available Retrofit Technology (BART) report dated

September 2010 and the associated NOx Reasonably Available Control Technology (RACT)

assessment. Specifi<:ally, Alcoa's responses addr~ the comments received on 14 October 2010

in your ","mail to the undersigned Oordan Parent, Alcoa). l\'YSDEC comments are identified in

,talles. and Alcoa responses follow each respective romment.

BART S«tion 1.1:

1. Why aren't roo/monitorI"rnl55Ums from tilt potline roalwl1!d as a possible SQUm' of~m'55lOn

~duction?

Control of roof monitor emissions was eliminated [rom consideration based on the dear

e.::onomic infeasibility of controlling such a large volume of exhaust gas with a relatively low

pollutant concentration. Specifically, total particulate matter (PM) concentration in the roof

monitor exhausts are typically in the range of 0.2 mgJdscf ....ith an exhaust flow typically

greater than 4 million dsdm. Control of this element of the potline PM emission would dearly

exceed the BART e.::onomic feasibility threshold. Regulatory development studies corroborate

this rationale and have collCiuded that roof monitor controls are cost prohibitive. For example,

Appendix B of CSEPA's NBasis and Purpose" document for the Primary Aluminum Maximum

Achievable Control (MACT} Standard concludes that the use of wet scrubbing technology to

control PM emissions ranged from about $13,000 \0 o\'er 542.000 per ton.

2. The PM-lO emisswns from the potlme utilized in tile BART analY51S are 143 tpy "'h,1e the postmo<krnizatWn PM-lOemi55ionsfrom tile pallin<: al? 165 tpy. \'\Ihat 's tile sourceo/this d'scrqancy'

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The 143 TPY PM·I0 emission rate represents the emission from the potline stack emissions only

(the A-398 stack emissions). The roof monitor emissions were excluded for the reaSOn stated

above. Total P~I·1O (stack and roof monitor) emissions reported for the post-modernization

pollines are actually 168 TPY (not 165). Please see the below basis:

A·393 • 1 91 1 lbs 1':\1_10 149.298 'onAI 1 'on 143 TrY

ton AI

'"' ~,.

J.lornlor - 0.339 lbsPM·]O 149293 IOn AI ,". •

~" "'"

'"' ~,.

To..l _ ,.

'"

3, 1k NO, emISSIOnS from the boilers should bi based On boIler PTE and not titt' future actual emissions.

'The PTE should be based an the maximum ~rmit!<'d NO, em15SlOn rale unless the faCility is ll·illmg to

lUapt a lmn'r pownMl emISSIOn I,mlt. 'The PTE for NO, alillt ptrmltemisswn l,mit rJfO.3Ib/MNfBIll is

1051 tpy.

Alcoa is <:ommitted to maintaining annual boiler NUx emissions to the level ""presented as

future actual rate in the modernization permit application and assumed that this rate would be

incorporated into the permit as an enforceable tenn.

BART Se<:tion 2.1.1:

4. Since a wd,um-«<sed wet scrublnng syslem is u"li",d successfully at the Alcoo Eas' Plant it would be

nice to 'itt the comple'e economic analysis rJfa SImilar sys!<'m at'he Alcoa \tWs, pumt.

As stated in Section 2.1.1 of the BART report, Alcoa considered the use of sodium based

scrubbing technology and found that limestone scrubbing options had some significant

advantages including, a solid waste stream that is mO"" environmentally friendly; a bleed

stream that is 0; to 10 times smaller; a wastewater treatment advantage with associated co:st

savings; a more cost effective reagent; and a reduced nero. for fresh water rinsing.

In addition, Alcoa·s experience at the East Plant has also revealed a significanl water treatment

issue associated with the sulfate levels in the scrubber blowdown. The result is the inability to

effectively treat fluoride in high sulfate concentration wastewaters prior to discharge, thus

jeopardizing compliance with federal Effluent Limit Guideline (ELG) 40 CFR421.l3n, for wet air

pollution OO11trol.

For these reasons, a direct cost analysis of the sodium based technology was determined to be

unnecessary. The cost is recognized to be approximately the same as the co:st estimate

developed for the limestone slurry forced oxidation system. and sodiwn based technology is

recogniZed to have the above referenced technical disadvantages.

BART Section 2.2.1:

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5. Alcoa should prol'ldt an aS5eSsmentofa sodlum-ba5ed wet scrubbing system jJr the anodt baklng

furMas.

Please see the above referenced response to comment No... abo'·e.

BART Se<:non 2.3.3:

6. iJ\1ult PM-l0emlSSlan lilt.> IS Alcoo pr0p05lngjJ. BARP 15 It the r:nstmg ptmllt limit. the Histing

emIsSIOn lilt.>, or SOme mllU' ll'ith the pTt'SllmptH'e limit ran~ conlmned In MANE-VU's FIl'f'-fa£tor

analysis'

As stated in Section No. 2.3.3 of the BART report. given the low PM emission rate, and the

insignificant aff"<:t of P:>Ol on the Iotal visibility impairment. Alcoa proposes that the existing P:>01

emission rate satisfies BART (i.e.; the current permit limit of O.llbs per MMBtu).

NOx RAcr Sedion 3.5,

7. Huwold all' lhe cumnt low NO, bu"",rs In the ""'lers! Alcoo should Im'f'shgale the possilnilty of

inswJling IIe'W loTI' NO, burners tlml could prmndt a mllnufaclureTs guarantud emISSIon mit that Is

lowe. than the cu.....nt RACT hmlt 0f0.3lb/MMBlu lind possibly mtl't Ihe 1U'lI' RACT limit of0,15

Ib/MMbtu.

The cuTTentlow KOx burnel'$ were installed in 1998. The boilers have established emission

rates through recent testing of 0.08 Ib/MMBtu and 0.27 lbIMMBtu when firing gas and oil

respectively. This actual rate is lower than the current RACT limit of 0.3 Ib/MMBtu On an

annual average basis, given the ratio of fuel oil to gas combustion.. boiler acrual emissions do

meet the new RACT limit of O.13lb/MMBtu. Since the boilers already have low NO" burners

(1998 vintage), use flue gas recirculation firing technology. and meetlhe new NO" limit on an

annual average basis: Alcoa did not develop a cost analysis for bumcr replacement that would be

focused exclusively on reducing oil fired emission to below the new NOx limit of 0.15

IbsIMMBtu.

BART Appendix A - H~tch SO, Prefe~sibililyStudy:

2 - Summary:

8. Halch sw.ted lhat the pna oflhe usa system inrllultd absorbers 1l11h five spmy l.n'tls lind five

pumpslind that Hatch belia'f'd a 95% rernOl-'01 ofso, could be oclria'td u1th fewer sprrry kt'tls Huw

much Ion",. would the rost be n'Ith fe""" spray let",ls?

Based on information provided by Hatch. the inclusion of five full spray levels in the absorber

tower design is found to be conservative and comes from the application in power plants where

this is a common practice. Hakh has indicated that the total can be reduced by at least one full

spray le"el (possibly h\-'o) including a pump for each absorber tower. If one spray level could

be reduced, it would eliminate the following equipment and associated capital cost in an

absorber tower:

• one set of piping

• one set of spray nozzles

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• a recycle pump ('<Jmplete with motor and controls

• one large '-alve in the suction of the pump

• five ffft of absorber tower ht>ight; and

• one set supporting beams inside the absorber tower.

Hatch has estimated that the associated cost reduction is in the order of 1.5 percent of the total

installed costs (approximately $3.1 in uSD). This reduction has only a marginal affed when

applied to the cost effectiveness evaluation, and still leaves the total c05t effectiveness above

512,000 per ton of SO, controlled.

9. Hatch slated thai a small cost 5/lv;ng "':rnld be realiud uSlllg a conl'fnlronal II"", wf'l scrubblllg

~tem and suggesled thai sud, a system should be cDr,sidt>red as all optlOIl. Did Ale,., perform an

eCOllom;c analysisfor a<lJn"rnt!ollallllnl" "'rt saubbmg system?

Hatch has completed an economical analysis of wet lime scrubbing although this was not

speocifically done for Alcoa's Massena operations. In Hatch's experience the wet lime scrubber

has a 7 percent lower capital cost to install and a 5.5 pera-nt lower capitali7.ed. cost per ton of

metal relative to the L5FO process. nus would mean that for the Massena operations, the total

installed costs for conventional lime wet scrubbing are in order of 5194 million usn (,-ersus

5208 million for LSFO). While this is lo.....er than the LSFO process, the difference is such that

the required overall investment and cost effectiveness is still in the same order of magnitude

and well above the threshold ofS5500 per ton.

BART Appendix B - Siemens Energy Propos~l:

10. \'VI,"!! wasn't tilt' S...""'ns quote, fd"ch "'as 569 mill,oll for equ,pmellt and ;nsta!lnlwn ofa one hm",r

u",1 Jlue gas desuljunzalwn (FGD) absororr, u5l'd ,n calmlahng tilt' cost eJfectifoeness ofrelllCl'mg so,

from lilt' poW"" erhaust' The Siemens estimate,s 533 ml1l;OIl less than the Babcock quote for a s'milar

system.

Based on information provided by Hatch, the Siemens proposal had a different scope than that

provided by Balx:ock. Specifically, the Siemens proposal contains only one absorber tower, one

gypsum de.....atering unit and one centrifugal fan which are insufficient to assure BART

compliana-, To provide 100% up-time, almost tv.·ice the amount of equipment offered by

Siemens is required. Further, Hatch has indicated that the installation costs provided by

Siemens are too low. Hatch's experience is that costs to install FGD systems are more in the

range of 50 percent of the total direct costs (the installation of FGD at an aluminum smelter is

much more uncommon than at a power plant). Given these reasons, Hatch found that the

Balx:ock Power scope was more complete, provided more reliable cost information, and was

more appropriate as a primary source for the report.

11. 5..."..."s stated tilat Iht'y «11et",d a dry FGD typr: spray dryer ab50rorr may «SUIted for control of

so, ffl/isswnsfrom t~ potli"", \'VI,"!! was I"is option not fi'<lluated?

Siemens based its comment regarding the use of a dry FGD scrubber on the application of this

technology in coal fired power plants combusting low suUur coal. The Akoa application is a

much different scenario. Dry scrubbing control for a smelter was reviewed by HATCH and

determined to be technically infeasible due to: insufficient exhaust gas temperature from a

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smelter (in power PWlt applia.tions the reagent is injected into the boiler dischuge when,> the

temperature is aoo..~ the re;oction temperature required for a.bsorption on the lIbsorberrt), the

technology has not mn demonstrated on a large-scale itS no smelter emplo)'5 this technology,

and the la.rge phY'5ical volume required - the requirement for a dl')' filter S}'5tem is mudt larger

tha.n the ~'olume in a wet pr0ce55. For ~lassena thi!; wOl.lld rne..n that a separate...t of

filters would be requlrtd, lind there is simpl}' not enough space for this applia.tion.

Additionally, if the technology was applicable, the dl')' process has a mIlCh higher operating

enst due to lower utilization of the reagent and higher power COItSI.lmption. B«ause all of the

gasesrould be addressed by a wet scrubber with a much smaller volume, the dry process was

excluded from further study.

Thank you for your assistance with this maUer. [f you have any questions or comments. please

do not hesitate to contact me at (315) i64-4737.

~;;~/v--- kdanJ. Parmi

Sr. SllIff Environmenllll Enitnft'r

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