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DEPARTMENT OF ENVIRONMENTAL QUALITY

AIR QUALITY DIVISION

Permit Application Analysis

AP-3545

November 18, 2008

"" NAME OF FIRM:

NAME OF FACILITY:

FACILITY LOCATION:

" TYPE 'OF OPERATION: ..

RESPONSIBLE OFFICIAL:

(", MAILING ADDRESS:

.¥••

':, TELEPHONE NUMBER:

,I R,EVIEWERS:

<.;, PURPOSE OF APPLICATION:

Mountain Cement Company

Laramie Cement Plant

SE'/. Section 17, TI5N, R73W

Albany County, Wyoming

POItland Cement Plant

Phil Lane, Plant Manager

5 Sand Creek Road

Laramie, WY 82070

(307) 745-4879

Andrew Keyfauver, NSR Permit Engineer

Don Watzel, Air Quality Modeler

Mountain Cemcnt Company submitted an application to modify operations at the Laramie Cement Plant

with the replacement of the two existing long-dry kilns (K I and K2) with a fivc-stage cyclone preheater

rotary kiln, The kiln will be designed to producc 963,600 tons of clinker annually which is approximately

a 20% increase in clinker production over the currently permined level of 80 1,500 tons of clinkcr per

year. In addition, the new kiln will be fired on coal, petroleum coke, or natural gas,

Mountain Cement Company replaced an ESP with a baghouse to control particulate emissions from Kiln

.c:' #2 under pcI'm it waiver AP-4004, Under the waiver the baghouse retained the same particulate emission

limit as the ESP, and a revised emission limit was to be established with the application for the new kiln

at the facility, The Division is proposing to establish an emission rate of 0,008 grldscf (0, I Iblton clinkcr)

and 6,2 Iblhr for the baghouse controlling Kiln #2, Additionally, the Division is proposing the installation , '

ofa PM continuous emission monitor (CEM) on the Kiln #2 baghouse as this baghousc will be utilized to

control the new kiln,

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Mountain Cement Company - Laramie Cement Plant

AP·3S45 Application Analysis

Page 8

Table VI

Mountain Cement Company

Hazardous Air Pollutant (HAP) Emissions

HAP TPY

Arsenic 0,01

Beryllium 0,0003

Cadmium 0,0011

Chromium 0.004

Hydrogen Chloride 67.45

Mercury 0.06

Lead 0.04

Selenium 0.10

acenaphthylene 0.06

Benzene 7,71

benzola)anthracene 0.00002

benzo(a)pyrene 0.0001

benzo(b)fluoranthene 0.0003

benzo(g,h,I)perylene 0.00004

benzolk)fl uoranthene 0.0001

chrysene 0.0001

dibenz(a,h)anthracene 0.0003

fluoranthene 0.004

fluorene 0.01

formaldehyde 0.22

naphthalene 0.82

phenanthrene 0.19

pyrene 0.0021

Total 76.62

CHAPTER 6, SECTION 2 - BEST AVAILABLE CONTROL TECHNOLOGY (BACT):

Per the requirements of Chapter 6, Section 2 of the WAQSR, all facilities must demonstrate the use of

BACT. Therefore, Mountain Cement Company conducted a BACT analysis for the control of pollutants.

• NO, Emissions

Control Options

Mountain Cement Company identified the following technologies for the control of NO, emissions from

the proposed preheater kiln at the Laramie Cement Plant:

Low NO, Burners (LNB)

Flue Gas Recirculation

Multi-Stage Combustion

Good Combustion Practices
Mountain Cement Company - Laramie Cement Plant

AP-3545 Application Analysis

Page 9

Selective Catalytic Reduction (SCR)

Selective Non-Catalytic Reduction (SNCR)

Low-NO, burners control the formation of NO, by controlling the mixing of air and fuel, causing

off-stoichiometric combustion (uses excess air). LNBs are designed to reduce peak flame temp, and

residence time which is the main cause of NO, formation. The most common fornls of LNBs arc staged

air or staged fuel burners usually designed for boilers.

Flue gas recirculation is intended to reduce the oxygen content of the primary combustion air used for the

main burner pipe, thereby lowering the peak flame temperature in the burning zone.

Multi-stage combustion is designed to burn fuel in two stages. Staged air combustion suppresses the

formation of NO, by operating under fuel-rich, reducing conditions (less than stoichiometric oxygen) in

the flame or primary zone where most of the NO, is formed. This is followed by oxygen-rich conditions

in a downstream, secondary zone where CO is oxidized at a lower temperature with minimal NO.,

formation.

SCR reduces NO, emissions by injecting ammonia into the exhaust gas stream upstream of a catalyst.

The ammonia reacts with NO, on the catalyst to fonn molecular nitrogen and water vapor. For the SCR

system to operate properly, the exhaust gas must be within a temperature range of 300 to I 100°F

depending on the catalyst type used.

Selective non-catalytic reduction (SNCR) reduces NO, emissions by injection of ammonia or urea into

the exhaust gas stream. SNCR is similar to SCR in that both systems use ammonia to react with nitrogen;

however, SNCR operates at higher temperatures than SCR and does not use catalyst. The effective

temperature range for SNCR is 1SOO to 2 J 00 OF.

]Oliminate Technically Infeasible Option~

Based on an initial evaluation of the identified control technologies, Mountain Ccment Company

eliminated flue gas recirculation, multi-stage combustion, and SCR. rlue gas recirculation was

eliminated as reducing conditions caused by oxygen deficiency are detrimental to maintaining cement

clinker quality. Multi-staged combustion was eliminated as this technology is applied to

preheater/precalciner kiln systems and not stand-alone preheater kiln systems. SCR was eliminated as

these systems have been proven to be unsuitable as the fine alkaline dust from the cement process inhibits

catalyst activity.

Rank Remaining Technologies

The following NO, control technologies are ranked according to the level of emission rates achievable

(control effectiveness);
"aufltllin Cement Compllny - Laramie Cement Plant

AP-J545 Application Analysis

I'age 10

Table VII

Mountain Cement Company

Ranking of NO, Control Technolo!!ies

Control Technology Emission Rate Tons per year (Ib/ton clinker)

SNCR/Low NO, Burners 2.0 963.6

Low NOx Burners 4.0 1927.2

Good Combustion Practices 5.9 2842.6

Evaluate Remaining Technologies

Mountain Cement Company proposed Low NO, burners as their base case for NO, control for the

. ,... proposed kiln. Therefore, Mountain Cement Company further examined the environmental, energy, and

,- economic impacts of installing SNCR in addition to Low NO, burners. Economic impacts for SNCR

were evaluatcd over a range of control efficiencies (20-50%). The following table shows the average cost

effectiveness for controlling NO, emissions with the use of SNCR in addition to Low NO, burners.

Table VIII

Mountain Cement Company

Avera!!e Cost Effectiveness NO,

Additional Emission (%) Control Emission Rate Annual Cost Cost Effectiveness Reduction (tpy) Reduction

Case I 20 3.2 Iblton clinker $1,748,518 $4,540/ton 385.4

Case 2 30 2.8 Ib/ton clinker $1,796,698 $3, II Olton 578.2

Case 3 40 2.4 Ib/ton clinker $1,844,878 $2,390/ton 770.9

Case 4 50 2.0 Iblton clinker $1,893,058 $1,960/ton 963.6

The average cost effectiveness is the total annualized cost for the option, including capital cost and annual

operating and maintenance costs, divided by the emission reduction. The Division considers the average

cost effectiveness to be reasonable for all four options. In addition to average cost effectiveness, the draft

1990 New Source Review Workshop Manual provides a method to evaluate incremental cost

effectiveness between dominant options known as the least cost envelope. For this method, a plot of

annual emission reduction vs. total annualized cost is produced and the dominant control options are

indicated by fitting a curve or line through the lower and right most points. Points above and to the left of

the line are considered inferior controls because points on the line provide more emissions reduction for

less money. The lease cost envelope for NO, control is shown below:
NO. Least Cost Evelope

$1,920,000 ,------r---------,..----_,_---

Mountain Cement Company - Laramie Cement Plant

AP-3545 Application Analysis

Page II

_. , $1,900,000 .

$1,880,000

$1,860,000

)

$1,840,000

"

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,

c $1,820,000

i

------1

-,

I

i i ·r·---·------._--,--- I '

Cast 3

i _._- __••-1.__.. '-"--'-i"-

$1,800,000

Case 2

400 500 800 700 800 900 1000

I

i ·_--t'--_·

CaSt I !

$1,780,000

$1,760,000 r-·-----r ---I

51,7040,000 +-----r--------;----_-----4-----4------;----~

300

.f

NOx Emission Reduction (tpvl

All of the options are on the curve and are, therefore, dominant options. The incremental cost

effectiveness for all the options is calculated in the following tablc_ Thc incremental emission reduction

and incremental increase in total annualized cost is the difference in these values for each option from the

previous table_ The incremental cost effectivcness is the incremental increase in total annualized cost

divided by the incremental emission reduction.

Table IX

Mountain Cement Company

NO, Incremental Cost

Incremental Emissions Incremental Increase in Incrcmental Cost

Options Compared Effectiveness Reduction (tpy) Total Annualized Cost ($) ($/ton)

Case I and Case 2 192.8 48,180 250

Case 2 and Case 3 192.7 48,180 250

Case 3 and Case 4 192_6 48,180 250

[n this case, the average cost effectiveness for all options is clearly within thc range the Division has

considered acceptable. The Division considers the incremental cost effectiveness of $250 Iblton

reasonablc for an additional 193 tpy emission reduction. Therefore, the incremental cost effectiveness is

considered reasonable for an emission level of2 Ib/ton clinker (Case 4)_
Mountain Cement Company - Laramie Cement Plant

AP-}545 Application Analysis

Page 12

As part of their analysis for SNCR, Mountain Cement Company presented information that additional

loading of ammonia in the flue gas could lead to the formation of a detached plume, and that this detached

plumc could potentially exceed opacity standards. Sub-micron aerosols consisting primarily of N/-l.C1

and (NH.),SO. are considered to be the major constituents of detached plumes. These compounds are

formed by the reaction of ammonia with chlorides and sulfates in the exhaust gases.

The Division reviewed the EPA's RACT/BACT/LEAR Clearinghouse (RBLC) for permits with NO,

limits associated with portland cement plants. The five (5) most recent permits entered into the

clearinghouse (2004-2006) indicate that recent determinations have required the use of SNCR for the

control of NO, with pennined levels of 1.95 Ib NO/ton clinker on a 30-day rolling average.

Additionally, the technical analyses for these permits also indicated the possibility of the formation of a

detached plume with the use of SNCR.

The Division contacted the Florida Department of Environmental Protection (FDEP) regarding the

CEMEX - Brooksville Cement Plant which has preheater kilns controlled with SNCR. FDEP indicated

that these kilns are limited to 2.0 Ib/ton clinker NO, based on a 30-day rolling average and that these kilns

have actual NO, emission rates in the range of 1.5-1.7 Iblton clinker. FDEP also indicated that detached

plumes are a possibility with SNCR, but that any issues associated with a detached plume can be

remedied. One such remedy consists of adding lime to the top of the preheater tower.

During review of this application, EPA proposed revisions to Subpart F of 40 CFR part 60 which is a new

source performance standard for portland cement plants. In the proposed revisions to Subpart F, EPA has

proposed a NO, emission limit of 1.5 Ib/ton of clinker on a 30-day rolling avcrage for sources

constructed, reconstructed or modified after June 16, 2008. The proposed NO, limit in Subpart F will

apply to all kiln types, but the proposed NO, limit is based on the operation of preheater/precalciner kilns

and not preheater kilns. However, for preheater/precalciner kilns to achieve this NO, emission rate it

would require the installation of SNCR. It should also be noted that EPA considered the possibility of

SNCR systems creating a detached plume when they established the NO, Iimit under the proposed

revisions to Subpart F.

Select NO, BACT (Conclusion)

Based on the cost effectiveness and incremental cost of installing SNCR, the Division considers SNCR

with Low NO, burners with emission limits of 2.0 lb/ton clinker (30-day rolling average) and 220 Ib/hr

(30-day rolling average) as representing BACT for NO, for the preheater kiln. The Division evaluated

Mountain Cement Company's concem regarding the presence of a detached plume; however, after

discussions with FDEP and reviewing EPA's proposed revisions to Subpart F the issues regarding a

detached plume can be remedied. The Division will propose that NO, emissions from the kiln be limited

to 2.0 Ib/ton clinker. However, as the EPA revisions to Subpart F (includes NO, limits) are not final, the

Division will require Mountain Cement Company to provide a report on the impact of the final Subpart F

revision as discussed in the new source performance standards section of this analysis. If the report

identifies that the preheater kiln is subject to a lower NO, limit, then the Division will administratively

amend thc permit to reflect the lowcr limit.