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

 

