Date: May 2012

Subject: Analyses of Data Received Between Proposal and Promulgation of Part 60, 

Subpart Ga

Nitric Acid NSPS Review

EPA Contract No. EP-D-11-084; Work Assignment No. 0-01 

RTI Project No. 02103199.000.001

From: Melissa Icenhour

To: Nathan Topham

OAQPS/SPPD/MICG (D243-02)

U. S. Environmental Protection Agency

Research Triangle Park, NC 27711

Introduction

In submitting comments on the proposed rule, NSPS Review of Nitric Acid (Subpart Ga), 

American Chemistry Council (ACC) mentioned that a separate NOX emission standard should be 

developed for small single pressure units. No additional continuous emissions monitoring system 

(CEMS) data were received during the public comment period. The EPA held a teleconference 

with representatives of ACC on January 11, 2012. As a result of the meeting, ACC volunteered 

to provide (CEMS) nitric oxides (NOX) data for multiple monopressure nitric acid plants by the 

end of the day on January 16, 2012 See Teleconference with American Chemistry Council on 

January 11, 2012.

Submissions were received from Dow, DuPont, and LSB Industries (owners of El Dorado

Nitrogen). As shown in Table 1, the NOX emissions were generally higher than the final 

emission limit. The average emissions for some facilities could not be determined because hourly 

data was not supplied. In the case of Dow Sterlington, concentration data were supplied as 3 hour 

averages. Therefore the 30 operating day emission rate could not be calculated. All data and 

analyses are contained in Docket EPA-HQ-OAR-2010-0750.

The following paragraphs summarize the data received from Dow, DuPont, and LSB

Industries.
Dow-Sterlington. 

Dow submitted data for 1 nitric acid plant in Sterlington, Louisiana. As discussed 

previously, Dow did not submit hourly averages so the analysis was limited. There were 5,812 

data points ranging from 0.0 lb NOX/ton acid to 12.37 lb NOX/ton acid. The median was 0.42 lb 

NOX/ton acid and the average was 0.72 lb NOX/ton acid.

The Sterlington nitric acid plant is a single pressure design, employing extended 

absorption and NSCR as NOX abatement. The plant produces 200 tons per day of 100% nitric 

acid. However, this plant could improve the performance of their NSCR by replacing the catalyst 

more often. According to the facility, the design life of the catalyst is 15 years but the actual life 

has been 25 years. 

If modifications are made to this plant such that the plant becomes subject to Subpart Ga, 

the plant could improve emissions reductions by replacing the catalyst more often.

DuPont- Pascagoula. 

DuPont submitted data for 1 nitric acid plant in Pascagoula, Mississippi, and 1 nitric acid 

plant in Beaumont, Texas.

The Pascagoula plant began operation in 1992. It has a single pressure design with no 

extended absorption and uses SCR as NOX abatement. The plant produces 230 tons per day of 

62% nitric acid. This plant could also improve the performance of the abatement device by

replacing the catalyst more often. According to the facility, the design life of the catalyst is 9 

years but the actual life has been 13 years. The supplied hourly averages show that the facility 

emits approximately 1.3 lb NOX per ton acid except for one hour each day where the hourly

average is approximately 6.0 lb NOX per ton acid.

If modifications are made to this plant such that the plant becomes subject to Subpart Ga, 

this plant could improve emissions reductions by employing extended absorption and by

improving the effectiveness of the SCR by replacing the catalyst more often.

See Figure 1 for a plot of the 30 operating day rolling emission rates for the Pascagoula 

plant during 2011. Emission rates range from 0.56 to 1.63 lb NOX/ton acid but 82% of the data 

were greater than 1.0 lb NOX/ton acid.
DuPont-Beaumont. 

The Beaumont plant began operation in 1971. It has a single pressure design with no 

extended absorption and uses NSCR as NOX abatement. The plant produces 250 tons per day of 

63% nitric acid. Hourly data were not supplied so the 30 operating day rolling emission rates

could not be calculated. The plant supplied 24 hour averages which range from 0.00 to 1.97 lb 

NOX/ton acid and averages 0.79 lb NOX/ton acid.

If modifications are made to this plant such that the plant becomes subject to Subpart Ga, 

the plant could improve emissions reductions by employing extended absorption or installing an 

SCR.

LSB Industries-East and West. 

The East and West units began operation in 1962 and are not subject to subpart G and are 

controlled by an SCR. The East unit produces 300 tons of 52%-58% nitric acid per day and the 

West unit produces 288 tons of 52%-58% nitric acid per day. According to the facility, the 

design life of the SCR catalyst is 11 to 15 years. The data submitted by the company covered the 

period of January 2011 through December 2011. The catalyst was replaced in August 2011, 

which means that the data from January through July 2011 is likely to be higher than typical 

because the catalyst was near the end of its useful life.

Also, the SCR unit is located after the gas expander. According to Jeremy Richard of 

PSC Geismar (see document 0062 in docket EPA-HQ-OAR-2010-0750), the mixing of gas and 

ammonia within the SCR is not ideal at this location. For best practice, the SCR should be 

located before the gas expander. Therefore, the East/West units are poorly performing plants and 

are not consistent with best system of emissions reductions.

If modifications are made to these plants such that the plants become subject to Subpart 

Ga, the plants could improve emissions reductions by changing the location of the SCR, and 

replacing the catalyst more often.

See Figure 2 for a plot of the 30 operating day rolling emission rates for the East nitric 

acid plant during 2011. Emission rates range from 4.4 to 13.0 lb NOX/ton acid and average 8.22 

lb NOX/ton acid.

See Figure 3 for a plot of the 30 operating day rolling emission rates for the West nitric 

acid plant during 2011. Emission rates range from 2.4 to 11.9 lb NOX/ton acid and average 6.1 lb 

NOX/ton acid.
LSB Industries-Cherokee No. 2 and DMW.

These nitric acid units have single pressure designs and only use extended absorption for 

NOX abatement. Hourly data were not supplied for the Cherokee No. 2 plant so the 30 operating 

day rolling emission rates could not be calculated. The plant supplied 24 hour averages which 

range from 0.04 to 3.83 lb NOX/ton acid and average 2.57 lb NOX/ton acid.

If modifications are made to these plants such that the plants become subject to Subpart 

Ga, the plants could significantly reduce emissions reductions by installing an SCR or an NSCR.

See Figure 4 for a plot of the 30 operating day rolling emission rates for the DMW plant

during 2011. Emission rates range from 3.0 to 5.1 lb NOX/ton acid and average 3.88 lb NOX/ton 

acid.

Conclusions. 

The additional data received included nitric acid plants that are not currently subject to 

subpart G, are not currently controlled, or are generally not employing the best system of 

emissions reductions (BSER). These facilities may need to install additional controls to comply

with subpart Ga if they are modified or reconstructed and trigger the standard. See Impacts of 

Nitric Acid NSPS Review-NOX (Updated memo for Final NSPS). However, these facilities do not 

illustrate that an emission standard of 0.50 lb NOX/ton acid is not achievable and thus would not 

have impacted the level of the standard in the final rule.
Table 1. Facility Data Received in January 2012

Plant Location Unit Year nitric acid 

plant 

constructed

Year of 

Data

Type Control 

device

30 operating day rolling 

emission rate

Highest Emission Rate

(lb NOX/ton acid)

Dow Sterlington ----- 1976 2011 Monopressure NSCR -----

a

DuPont Beaumont ----- 1971 2009-

2010

Monopressure NSCR -----

b

DuPont Pascagoula ----- 1992 2011 Monopressure SCR 1.63

LSB Industries East 1962 2011 Monopressure SCR 13.02

LSB Industries West 1962 2011 Monopressure SCR 11.87

LSB Industries Cherokee Unknown 2011 Monopressure None -----

b

LSB Industries DMW Unknown 2011 Monopressure None 5.11

a Only 3 hour averages were supplied.

b Hourly data were not supplied.
Figure 1. DuPont Pascagoula Nitric Acid Plant in 2011
Figure 2. LSB Industries East Nitric Acid Plant in 2011
Figure 3. LSB Industries West Nitric Acid Plant in 2011
Figure 4. LSB Industries DMW Nitric Acid Plant in 2011