The most critical aspect of the survey involved compiling both capital and operating costs

associated with NOx control technologies to allow for the calculation of cost effectiveness (CE).

In an effort to enhance data consistency, TFI prepared a NOx CE calculator following the

procedures outlined in EPA's Air Pollution Control Cost Manual - Sixth Edition. The Manual

includes procedures to calculate NOx cost effectiveness for Selective Catalytic Reduction (SCR)

technologies. The Manual does not include specific guidance for Non-Selective Catalytic

Reduction (NSCR) nor does it include guidance to estimate cost effectiveness of nonconventional technologies such as extended absorption. The procedures to calculate cost

effectiveness of SCR are very transferable to NSCR and altemative technologies and were

therefore used throughout TFI's analysis.

The NOx CE data (dollars per ton) were converted to 2009 values using the US inflation

calculatorl. To convert to 2009 dollars, the Total Capital Investment tiCtl was converted to

2009 dollars, while the variable costs remained unchanged as the variable costs already reflected

current pricing.

Section 2: Member Contributions / General Summary

TFI circulated the NAP survey to each member with an active NAP. The following highlights

the number of members, sites and NAPs completing the survey:

o Number of companies completing survey: 12

o Number of facilities completing survey: 29

o Number of NAPs completing survey: 51

o The total HNO3 production capacity represented: 25,450 tons per day (þd)

o Weak Acid Producers (53-67%o): 50/51

o Strong Acid Producer (98-99.5%o): Il5I

Section 3: Summary of member NSPS status and existing permit limits

As part of the survey process, TFI requested that each member identify their NSPS Subpart G

status, as well as their current NOx permit limit expressed in lbsNOx/tHNO3. Lastly, TFI

requested that each member also include their actual emissions compared to that of their permit

limit. In summary, 34 of the 51 plants completing the survey are currently subject to Subpart G.2

I http://www.usinfl ationcalculator.com/

2 We note that an additional plant became subject to the NSPS after TFI's survey, bringing the current total number of plants

subject to the NSPS to 35 plants. However, because this plant was not subject to the NSPS at the time of TFI's survey, its status

(and, in turn, its data) is not identified in this memorandum as being subject to the NSPS.

2288210v2121436-002
Non-NSPS Source Analvsis

As shown in Figure 1, the NOx limits for the 17 non-NSPS sources vary significantly, from a

low of 1.0 lbNOx/tHNO3 (lb/ton) to a high of 13.1 lb/ton. The average limit is 5.421blton, and

the average actual emission rate is 2.89lblton.

Please note that each data point represents one NAP within the TFI survey.

Figure 1 -Non-NSPS Sources

Non-NSPS Sources

NOx [imits vs. Performance

74.OO

12.00

I 10.00

z

c 8.00

o

ð 6.00

z

3 4.oo

2.OO

+ Limit (lblton)

+Acutal (lblton)

NOx Averages

Limit - 5.42 lbs/ton

Actual- 2.89 lbs/ton

1357911131577

A

/ A.

^ ll 1

\

/ il \I \

Figure 2 highlights NOx limits and actual emissions for NSCR-controlled sources (6 NAPs),

while Figure 3 provides the same information for SCR-controlled sources (7 NAPs), both for

sources within the Non-NSPS Source category.

Figure 2 - Non NSPS Sources - NSCR

Non-NSPS Sources

NSCR NOx Limits vs. Performance

10.00

9.00

8.00

7.OO

6.00

s.00

4.00

3.00

2.00

1.00

+ Limit (lb/ton)

+Acutal (lblton)

m

o

z

r

c

o

x

o

z

4

NOx Averages

Limit - 3.65 lbs/ton

Actual- 1.78 lbs/ton
Figure 3 - Non NSPS Sources - SCR

Non-NSPS Sources

SCR NOx Limits vs. Performance

14.00

12.00

10.00

8.00

+ Limit (lblton)

+Acutal (lblton)

rYl

o

z

¿

E

o

x

o

z

€

6.00

4.00

2.00

NOx Averases

Limit - 6.76 lbs/ton

Actual- 3.3 lbs/ton

Of the 1 7 NAPs not covered by Subpart G, two sources utllize extended absorption for NOx

control and two sources have no NOx control. The permit limits for the extended absorption

only sources are 3.0 lbs/ton, while the permit limits for the sources with no NOx control are 10.0

lbs/ton. Further discussion of extended absorption as a means for NOx control is included in

Section 4 of this memorandum.

NSPS Source Analvsis

As previously referenced, 34 of the 5l NAPs completing the survey are subject to Subpart G. As

shown in Figure 4,the NOx limits for NSPS sources vary from a low of 0.3 lbs/ton to a high of

3.0 lb/ton. The average limit 1s 2.36lblton, and the average actual emission rate is 1.09 lbiton.

Figure 4 -NSPS Subpart G Sources

NSPS Sources

NOx Limits vs. Performance

3.s0

300

^^

/ V

l

I

ttJ v

/Vr

l

, l- \r Y ,t^/

V

1 3 5 7 9 111315777921232s27293t33

å 2s0

H

n 200

r

ó 1so

N

È roo

050

NOx Averases

Limit - 2.36 lbs/ton

Actual- 1.09 lbs/ton
Figure 5 highlights NOx limits and actual emissions for NSCR-controlled sources (10 NAps),

while Figure 6 provides the same information for SCR-controlled sources (17 NAPs), both for

sources within the NSPS Source category.

Figure 5 NSPS Sources - NSCR

NSPS Sources

NSCR NOx [imits vs. Performance

3.50

3.00

2.50

2.OO

1.50

1.00

0.50

+Limit(lblton)

+Acutal(lblton)

o

z

¿

E

o

x

o

z

l¡

NOx Averases

Limit - 2.31 lbs/ton

Actual- 0.58 lbs/ton

Figure 6 NSPS Sources - SCR

NSPS Sources

SCR NOx [imits vs. Performance

3.50

3.00

2.50

2.O0

1.50

1.00

0.50

+Limit(lblton)

+Acutal (lblton)

o

z

Ê

o

x

o

z

lt

NOx Averages

limit - 2.26 lbs/ton

Actual- 0.86 lbs/ton

As shown in Figures 5 and 6, there is little discernable difference between the permit limits for

NSPS sources using NSCR vs. SCR. Likewise, the overall performance of NSCR vs. SCR is

similar (0.58 lblton v. 0.86 lb/ton).

Of the 34 NAPs subject to Subpart G, five sources claim some form of absorption (extended or

chilled), with two NAPs claiming no NOx control. Six of these NAPs have a NOx permit limit

of 3.0 lbs/ton and the remaining source has a permit limit of 0.6 lbs/ton.
The five sources with extended or chilled absorption have act;;øl NOx emissions ranging from

2.1 to 2.75lbslton One source includes hydrogen peroxide injection within their extended

absorber and is able to achieve an actual emission rate of 0.52 lbs/ton. The two sources with no

NOx control have actual emission between 2.2 and2.76lbslton.

Section 4: Summary of NOx Air Pollution Control Technologies

The following statistics generally summarize the survey results with respect to the types of NOx

control applied for the 51 NAPs completing the NAP survey:

Table 1 - Summary of NOx control technologies

NOx Control Number of Sources

SCR

SCR with extended absorption 1

SCR with hydrogen peroxide 2

NSCR 14

NSCR with extended absorption 3

Extended absorption 5

Extended absorption with hydrogen peroxide 1

Chiller absorber 1

No control 4

Although SCR and NSCR are commonly considered "classic" NOx controls, several TFI

member companies use modifications to their absorption tower to enhance both HNO¡

production and subsequently reduce NOx emissions. Although these are not classic NOx control

measures, they do play an important role for certain facilities in meeting their NOx limits. As

such, absorption tower modifications should be considered a viable alternative to meet more

stringent NOx limits. However, the economics of an absorption tower modification may not

support such a decision, as these modifications can be very costly to existing NAPs.

The data summarized below focus on both SCR and NSCR technologies. The cost data

associated with absorption tower modif,rcations is not clear and could not be used to support

accur ahe NOx co st effectivenes s determinations.

In addition , the data summarized below includes only complete capital and operational cost data

sets to allow for a complete statistical analysis. Of the forty sources that apply some

combination of SCR or NSCR technology, twenty data sets for SCR technologies and eleven

data sets for NSCR technologies \Mere complete. This represents 78Yo of the entire groups. TFI

believes this is statistically significant andthatthe data is very representative of our member

companies.

20
Table 2 - Summary of NOx Cost Effectiveness

Installation

Criteria Date

Abatement

Cost (S/ton)

DE

l%l

Cost in

20oe (sl

20 in data set

scR

Average

Minimum

Maximum

Median

2000

t992

2009

1999

90%

75%

98o/o

9t%

s

s

s

s

s16 s

r1.4 s

3,359 s

277 s

s93

t1.4

4,359

296

LL in data set

NSCR

Average

Minimum

Maximum

Median

L985

1968

2008

1985

97%

8s%

LOj%

99%

2,790 s

377 5

9,776 s

3,696

408

10,656

s

s

s

s 1,891 s 3,794

As part of the analysis, TFI evaluated minimum, maximum, average and median values for all

variables as presented in Table 2. As shown, NSCR installations go back to 1968 and are in

general much older installations compared to the relatively newer SCR technology. The age of

these facilities also impacted the inflation percentages used to represent the abatement costs in

2009 dollars.

A further analysis of the destruction efficiency (DE) and installation dates for NSCR and SCR

across the entire data set is presented as Figures 7 and 8.

Figure 7 - NSCR NOx Control Efficiency vs. Installation Dates

NSCR lnstallation Dates and

NOx Control Efficiency

2020

2010

2000

1990

1980

7970

1960

1950

1940

t05o/o

t00o/o

9s%

90% r Install Date

85% 

-DE(%l

80%

7s%

t 2 3 4 s 6 7 8 9 1011

Please note that destruction fficiency cannot exceed 100%.
Figure I - SCR NOx Control Efficiency vs. Installation Dates

SCR lnstallation Dates and

NOx Control Efficiency

2015

20ro

200s

2000

1995

1990

1985

1980

720%

LOOo/o

80%

I Install Date

-DE(%)

13 5 7 91.1. 13 1517 L9

Although the destruction efficiency for NSCR is higher, the cost per ton of NOx abatedis also

significantþ higher. A further analysis of the key components of the abatement costs per ton is

provided below.

Our analysis focused on the analysis of three key variables that determine abatement costs:

1. Capital costs

2. Variable costs

3. NOx inlet mass loadings (tpy)

NSCR vs. SCR Capital Costs

Of the three key variables evaluated, the capital cost of the control systems had the least impact

on abatement costs. Although capital costs do play an important role, SCR and NSCR capital

costs are similar. In addition, these costs are recognized over a 2}-year horizon (consistent with

the useful life of the equipment) per EPA's Air Pollution Control Cost Manual (Sixth Edition).
As presented in Table 3, although the capital costs for NSCR are greater than SCR, the

difference is not appreciable. The only major difference in2009 dollars is due to the age of the

NSCR systems and the associated inflation rates.

Table 3 - Total Capital Investment Comparison

Total Capital lnvestment

lnstrumentation lnstallation

TCI Summary

Summary 2009 scR

20 in data set Average S e$szo S tgz,ooo S 88,305s tze,o$5 L,225,4495 7,787,694

Minimum$ 165,000s 15,000s 15,760s 43,340s zso,tooS sgr,ggr

Maximums 1,700,000s soo,æos 187,500s ¡go,oæs 2,530,000s 6,065,796

NSCR Median S SzSoæ S 150 000 S 62,000s 154000s 1,000,000s 1,386,799

11 in data set Average S ggs,szo S rza,s¿g S 89,206 5 245,315 S 1,449,590 S 4,713,64r

MinimumS 425,000S SO,OOOS 38,OO0S fO4SOOS 617,500S 1,137,033

MaximumS 1500,0005 308,447 S 136,000S gZ4O00S 2,210,000S 10,891,540

[Discussion of Figure 9]

Figure 9 - Total Installed cost comparison (2009 $)

Total lnstalled Cost (TCl)

31

29

27

25

23

2T

19

T7

15

13

11

9

7

5

3

1

S2,000,000 S4,000,000 S6,ooo,ooo S8,0oo,o0o S10,ooo,ooo S12,ooo,ooo

2009 dollars (USD)
Variable Costs

TFI evaluated the variable costs associated with both SCR and NSCR and observed a significant

difference between the two technologies.

As presented in Table 4, it is clear that the most significant annual variable expense for NSCR is

reagents (þdrocarbons). This variable alone is the most significant driver for NOx abatement

costs. Unlike NSCR systems, SCR systems use ammonia as areagent which is an insignificant

variable cost in comparison to the hydrocarbon costs for NSCR. SCR's largest variable cost is

associated with catalysts and their associated life expectancy and costs.

Table 4 - Variable Expense Comparison

scR Criteria

Variable Expenses

Maintenance Reagent Catalyst Catlyst life

Catalyst

5lv¡

20 in data set

NSCR

Average

Minimum

Maximum

Median

1&381 s

3,842 s

3zss0 s

15,000 s

145,219 s

s00 s

362,250 s

I2I,500 s

5

s

s

s

327,448

50,000

900,000

3M,413

7.3 s 54,L28

5.0 s 6,200

15.0 s L8o,ooo

6.0 s 43,750

11 in data set Average

Minimum

Maximum

Median

22,874 s

9,263 s

33,150 s

24,525 s

7,2æ,747 5

9r,740 s

2,318,745 s

1,300,000 s

s

s

s

s

277,7L5

L5,200

600,000

2æ,713

5.8 s 55,285

4.0 s 3,040

10.0 s 120,000

5.0 s 52,943

Figures 10 and 11 present the overall contributions of each variable cost category for NSCR and

SCR, respectively.

Figure 10 - NSCR Variable Costs

NSCR Variable Cost

Maintenance

2%

10
Figure 11 - SCR Variable Costs

SCR Variable Costs

Maintenance

4%

A fuither analysis of both reagent costs and catalysts costs across the entire

below.

Figure 12 - NSCR vs. SCR Reagent Costs ($/year)

Reagent Pricing

data set are presented

Variable Costs (S/Vr)

31

29

27

25

23

2T

T9

T7

15

13

7T

9

7

5

3

I

s1,000,000 s1,s00,000

I Reagent ($/yr)

S2,ooo,ooo S2,soo,ooo

The catalyst costs did not show an appreciable difference between NSCR vs. SCR. However,

across both control technologies, there is a wide range of costs and useful life depending on the

type and manufacturer of the catalyst. Figure 13 depicts the variations of catalyst costs and life

across both NSCR and SCR systems.

11
Figure 13 - Catalyst Cost vs. Useful Life Comparison

Catalyst Costs and Useful Llfe

L,OOO,OOO

900,ooo

800,ooo

700,ooo

600,ooo

500,ooo

400,ooo

300,ooo

200,ooo

L00,ooo

16

I4

1,2

10

8

6

4

2

r e¿t¿ly5f ($)

-Catlyst 

life (yrs)

t

I

FI I

.q

I T

I I

,/ II

I

NOx Inlet Mass Loadings

Once the capital and variable cost are determined, the last factor which impacts cost

effectiveness is the inlet mass loading of NOx to the control device. Capital and operating costs

for both NSCR and SCR are not linearly related to NOx loadings. Therefore, for sources with

minor NOx loading on either a ton per hour or ton per year basis will not tend to be as cost

effective as a source with heavy NOx loadings. Figures 14 and 15 present cost effectiveness

versus inlet NOx mass loadings.

12
Figure 14 -NSCRNOx CE vs. NOx Loading

NSCR NOx Cost Effectiveness

vs NOx lnlet Loading

512,000

slo,ooo

S8,ooo

S6,ooo

s4,0oo

S2,ooo

s4,500

4,000

3,500

3,000

2,500 r 200e (S)

2,OOO 

- 

NOx (tPY) lnlet

1,500

1,000

500

I T

À

T /\

I/ \ /\ tl

I T

I

TT

As shown in Figure 14,three of the four lowest NOx abatement costs are attributed to the highest

annual NOx pre-control mass loadings (tpy).

Figure 15 - SCR NOx CE vs. NOx Loading

SCR NOx Cost Effectiveness

vs NOx lnlet loadlng

s5,000

s4,5oo

s4,ooo

s3,5oo

s3,ooo

s2,5oo

s2,ooo

s1,5oo

s1,ooo

ss00

s4,500

4,000

3,500

3,000

2,500 r 2009(S)

2,000 

- 

NOx tpy (inlet)

1,500

1,000

500

tl

/t I

/l

V

I

r\AA ,1

I

YY \

lIlll.l,. I Irl,lt

13
Once again, as shown in Figure 15, the three most significant NOx abatement costs are

associated with the lowest NOx mass loading values.

Section 5 - N2O Abatement and Emissions

As previously discussed with EPA, TFI does not believe that EPA has authority under the NSPS

to regulate NzO emissions. EPA's regulation of an "air pollutant" under the NSPS is premised

on an "endangerment finding" - that the air pollutant "causes, or contributes significantly to, air

pollution which may reasonably be anticipated to endanger public health or welfare." CAA

$ 111(bX1)(A). N2O was neither specifically identihed as an "air pollutant" for purposes of the

original nitric acid plant source category when promulgate d in 19713 nor is it identified as an air

pollutant for any other NSPS. Further, because NzO has not been identified as an NSPS air

pollutant, EPA has not made the requisite endangerment finding to justifi regulating it under the

NSPS.

Finally, even though EPA has embarked on a review of the sufficiency of the current nitric acid

plant NSPS, as EPA has recognized, "[n]othing in the statute ties the endangerment and 8-year

review requirements." 73 Fed. Reg. 35838, 35859 fn.2 (June 24,2008). Given EPA's failure to

satisfy the NSPS statutory air pollutant listing and endangerment finding prerequisites to the

regulation of N2O, EPA's own admission that a periodic review of an NSPS does not trigger the

need to engage in an endangerment evaluation, and the piecemeal approach of the Clean Air Act,

TFI believes that NzO emissions are best addressed under comprehensive climate change

legislation.

Nonetheless, to gain an understanding of members activities relating to NzO as part of the survey

process, TFI requested NzO abatement and NzO emissions data from our members. As a result

of the data obtained, the following is clear:

l. Members are only now starting to gather NzO emissions data inpreparation for potential

abatement projects and the EPA Greenhouse Gas Reporting Rule. As a result,

representative data sets are not yet available.

2. One member facility has voluntarily installed two secondary catalyst projects for NzO

abatement and is currently evaluating options for the verification of the N2O reductions

through the soon to be published Climate Action Reserve (CAR) Nitric Acid Protocol.

3. No member is required to abate N2O, nor does any member have an N2O permit limit.

4. Members are evaluating the potential for NzO abatement and are evaluating timing, costs,

and facility - specific factors.

5. Based on the limited data sets, a "Best Demonstrated Technology" for NzO has not been

"adequately demonstrated" and, therefore, there is no identified "achievable" emission

standard for NzO. Essex Chemical Corp. v. Ruckelshaus, 486F.2d 421,433 (D.C. Cir.

r973).

3 See 36 Fed. Reg. 24876 (Dec. 23, l97I); Background Information Document for Proposed New-Source Performance Standards:

Steam Generators, Incinerators, Portland Cement Plants, Nitric Acid Plants, Sulfuric Acid Plants (August 1971).

I4
Section 6: Conclusions

Based on the detailed data obtained by TFI through this survey program, the following

conclusions can be drawn:

No two NAPs are designed alike. NAPs have a wide range of operating temperatures and

pressures as well as process configurations. Depending on the NAP design, the amount

of NOx (and the relative amounts of NO v. NO2) vary significantly. As a result, there are

serious cost implications in lowering the NOx limit to a uniform standard.

Current NSCR and SCR performance at NSPS Subpart G facilities average 0.58 and 0.86

lbs/ton, respectively. NSPS Subpart G facilities with some form of extended absorption

have actual NOx emissions ranging from2.L to 2.75|bslton, and two NSPS Subpart G

sources with no controls have actual emissions between 2.2 and2.76lbslton.

o NOx abatement costs for NSCR are generally greater than SCR based primarily on the

variable reagent costs necessitated by NSCR. Most often, NSCR installations date back

to aged facilities and are no longer common practice in the United States, however, there

are newer facilities with NSCR. NSCR systems must be integrated into a NAP's overall

energy balance, as the excess heat energy from the NSCR is used within the process.

. SCR, NSCR, and extended absorption remain the most utilized technologies; however,

costs and performance can vary widely based on a number of facility - specific factors.

o The use of extended absorption, chilled absorption and hydrogen peroxide injection are

potentially viable technologies to enhance the HNO3 process and further remove NOx.

NAPs should have the ability to evaluate this option in lieu of modiffing existing control

technologies if a more stringent NOx requirement is imposed.

SectÍon 7: Next Steps

Per our discussion, TFI and our Nitric Acid Subcommittee will meet with USEPA on November

18th at 1:30 to further discuss these results.

TFI would like to fuither discuss USEPA's NSPS questionnaire and its content, in an effort to

leverage the work that has akeady been done and minimize redundant questions to the extent

feasible.

15