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WASHINGTON, D.C. 

 

December 11, 2012 

VIA E-MAIL AND U.S. MAIL

ATTORNEYS AT LAW

WASHINGTON HARBOUR 

3000 K STREET, N.W. 

SUITE 600 

WASHINGTON, D.C. 20007-5109 

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foley.com 

WRITER'S DIRECT LINE 

202.295.4021 

rstoll@foley.com EMAIL

Scott Jordan, Esquire 

Office of General Counsel 

U.S. EPA 

1200 Pennsylvania Avenue, N. W. 

Mail Code: 2344A 

Washington, DC 20460

RE: Dyno Nobel Inc. Petition for Reconsideration of October 10, 2012

Dear Scott: 

 On behalf of my client Dyno Nobel Inc. (“DNI”), I am responding to the questions from EPA 

program staffers you forwarded to me in your e-mail of November 14, 2012, as clarified by your email of November 26, 2012. I will reprint each question from your e-mail, then provide DNI’s 

response to each. In our responses below, I will use the same acronyms used in our October 10, 

2012 administrative petition. 

Question 1. What information and/or data does Dyno Nobel have to demonstrate that 

retrofitting an NSCR controlled plant to add an SCR is technically infeasible? 

 DNI does not claim that retrofitting an NSCR controlled plant to add an SCR is technically

infeasible. We are, however, enclosing analyses performed by ERM-West, Inc. (ERM) on DNI’s 

behalf dated March 7 and July 31, 2012. (Attachments 1 and 2.) These analyses conclude that 

adding SCR technology to DNI’s Donora, PA NSCR plant would be economically infeasible. There 

is no fundamental difference between the Donora NSCR plant and other NSCR plants that would 

alter the conclusion that adding SCR to an NSCR plant generally is economically infeasible. 

 But I should hasten to add that we believe Question 1 – whether directed to technical or 

economic infeasibility – appears to side-step a critical legal point regarding DNI’s pending judicial 

and administrative petitions regarding the final NAP Rule of August 14, 2012. As stressed in the 

TFI comments and our administrative petition, EPA in its rulemaking process undertook no 

evaluation of the compliance costs associated with the 0.5 lb/ton limit for NSCR plants undergoing 

modifications. This is despite comments in the record showing that NSCR plants have 

fundamentally different attributes, and CEMS data in the record showing that NSCR plants were not 

meeting the 0.5 lb/ton limit. We thus contend that EPA had no basis to assume that NSCR NAPs 

undertaking a modification or reconstruction could comply with the final NAP Rule consistent with 
FOLEY & LARDNER LLP

December 11, 2012 

Page 2 

EPA’s compliance cost assumptions, and that this makes the final NAP Rule legally defective. 

 Question 2. What facility-specific cost analysis or other data does Dyno Nobel have 

showing that the costs of retrofitting an NSCR controlled plant to add an SCR are substantially 

higher than the costs of retrofitting a previously uncontrolled plant? 

 Please see our response to Question 1. In addition, as stressed in our administrative petition, 

a basic point of the comments in the record is that NSCR is not an add-on control technology (like 

SCR). Rather NSCR is built into, and an integral part of the operation of the NAP. Accordingly, as 

the comments demonstrate (and the ERM analyses show), adding an SCR to an NSCR plant (which 

has never been done) would be substantially more complex and costly than simply adding SCR to an 

uncontrolled plant. 

 This is demonstrated not only by the ERM analyses referenced in our response to Question 1, 

but also by the State of Georgia’s BACT determination for a PCS NSCR NAP in Augusta, Georgia 

(Attachment 3). Please see especially pages 6-9 of Attachment 3, where the Georgia DNR explains 

how adding an SCR to an NSCR plant would not be cost-effective. The Georgia DNR analysis also 

notes that there are no known plants that operate both NSCR and SCR technologies. 

 We believe Question 2 also side-steps the basic legal issues in DNI’s judicial and 

administrative petitions. EPA did not evaluate modification costs in issuing the final NAP Rule, and 

EPA offered no response to the comments in the record about the fundamental differences between 

NSCR and SCR plants. We believe this makes the final NAP Rule legally defective, and 

substantiates the grounds for the relief we seek through our pending administrative petition. 

 Question 3. What information does Dyno Nobel have to demonstrate that the J.R. Simplot 

(Helm, CA) plant that employs NSCR and meets the 0.5 lb/ton limit is not representative of the 

industry? 

 This question is phrased under the assumption that the Helm plant “meets the 0.5 lb/ton 

limit.” We recognize that the preamble to the final NAP Rule states that monthly data from the 

Helm plant ranged under the 0.5 lb/ton limit. EPA concluded that even though the monthly data 

were not directly comparable to continuous hour-by-hour data, the Helm plant could probably 

comply with the limit. 77 FR at 48437, col. 1. 

 But Simplot has informed us that because the current NSPS (subpart G) only requires the 

CEMS to measure up to 500 ppm, the monthly data EPA has relied upon does not account for higher 

peaks in the averaging that would be measured by the dual-span CEMS that the new NSPS (subpart 

Ga) requires. The new subpart Ga, of course, requires that emission peaks occurring during startup 

and shutdown must be taken into account in determining compliance with the 0.5 lb/ton limit. 77 FR 

at 48435. Thus, any assumption that the Helm plant would meet the 0.5 lb/ton limit continuously 

throughout the year cannot be substantiated based on the monthly data cited by EPA. 
FOLEY & LARDNER LLP

December 11, 2012 

Page 3 

 As to the Helm plant’s representativeness, Simplot personnel have informed us that they 

regard the Helm facility to be “a small facility” not representative of traditional NSCR plants. As we 

pointed out in our administrative petition, the Helm plant is rated at a mere 280 TPD and its average 

production is only 231 TPD. 

 Relating this information back to our administrative petition, the only bases on which EPA 

claimed to justify its refusal to subcategorize NSCR modifications were the hourly-by-hourly data 

from the DNI St. Helens plant (the “Oregon NAP”) and the monthly data from the Simplot Helm 

plant. We have demonstrated in our administrative petition that the Oregon NAP is not 

representative of NSCR plants in the U.S. And the monthly Helm data to which EPA referred 

cannot be relied upon because it was taken from instruments which could not account for higher 

peaks that can be expected during startup and shutdown and at other times throughout a year. 

Moreover, the Helm plant is very small. We believe this underscores the legal defects in the final 

NAP Rule and the need for subcategorization as requested in our administrative petition. 

Question 4. How would Dyno Nobel define the subcategory for modified/reconstructed 

facilities currently using NSCR, keeping in mind that CAA 111(b)(2) provides that EPA may 

subcategorize based on classes, types, and sizes? 

 Our administrative petition requests that EPA establish a subcategory for NSCR NAPs 

undergoing modification or reconstruction. We believe EPA’s record already is replete with data 

and information establishing that NSCR plants are a distinct category of NAPs and are 

fundamentally different in design and operation from plants that do not incorporate NSCR. In fact, 

we note that EPA’s Question 6 below accurately depicts the subcategory we seek: “a subcategory of 

modified/reconstructed NSCR controlled plants.” 

 Question 5. Does Dyno Nobel anticipate that any of their facilities that currently do not 

achieve the level of the standard will be modified or reconstructed and trigger subpart Ga? 

Yes. DNI plans to modify its Cheyenne, Wyoming NAP unit #3 in a manner that would 

trigger applicability of the new subpart Ga. 

 Question 6. What standard would be appropriate for a subcategory of 

modified/reconstructed NSCR controlled plants? 

Based upon an analysis of all relevant data regarding NSCR plant performance, for this 

subcategory DNI could support a NOx limit of 2.0 lb/ton of nitric acid produced, as a 30-day 

emission rate calculated based on 30 consecutive operating days. We note that this would require 

more than a 33% reduction off the current subpart G limit, especially when considering (as noted 

above) that the current subpart G limit does not require inclusion of startup and shutdown peaks to 

determine compliance (whereas the new subpart Ga does require such inclusion). 
FOLEY & LARDNER LLP

December 11, 2012 

Page 4 

 As I have mentioned in our phone conversations, we remain hopeful that EPA’s 

consideration of the limited request in our administrative petition can result in amendments to the 

final NAP Rule that will obviate the need for D.C. Circuit review. Please let me know when we can 

meet to discuss our petition and our responses to your questions. 

Very truly yours, 

Richard G. Stoll 

Attachments (3) 
ATTACHMENT 1 







ATTACHMENT 2 







ATTACHMENT 3 
Prevention of Significant Air Quality Deterioration Review

Of PCS Nitrogen Fertilizer – Augusta Plant

Located in Richmond County, Georgia

PRELIMINARY DETERMINATION

SIP Permit Application No. 14213

June 2004

State of Georgia

Department of Natural Resources

Environmental Protection Division

Air Protection Branch

Stationary Source Permitting Program

(SSPP)

Prepared by

Heather Cottrell – Chemicals Unit

Modeling Approved by:

Jim Stogner and Richard Monteith

Data and Modeling Unit

Reviewed and Approved by:

Heather Abrams – Chemicals Unit Coordinator

John Yntema – Acting SSPP Manager

Ron Methier – Chief, Air Protection Branch
SUMMARY....................................................................................................................................ii

1.0 INTRODUCTION..............................................................................................................1

2.0 PROCESS DESCRIPTION ..............................................................................................3

Nitric Acid Manufacturing Process.....................................................................................3

3.0 REVIEW OF APPLICABLE RULES AND REGULATIONS.....................................5

State Rules...........................................................................................................................5

Federal Rule - PSD..............................................................................................................5

Federal Rule – 40 CFR 60 Subpart G..................................................................................6

Federal Rule – 40 CFR 64 ...................................................................................................6

4.0 CONTROL TECHNOLOGY REVIEW..........................................................................6

Nitrogen Oxides (NOX).......................................................................................................6

Summary – NOX Control Technology Review for the C-002 Nitric Acid Plant ................9

Carbon Monoxide (CO).....................................................................................................10

Summary – CO Control Technology Review for the C-002 Nitric Acid Plant.................12

5.0 TESTING AND MONITORING REQUIREMENTS..................................................12

6.0 AMBIENT AIR QUALITY REVIEW...........................................................................13

7.0 ADDITIONAL IMPACT ANALYSES ..........................................................................20

8.0 EXPLANATION OF DRAFT PERMIT CONDITIONS.............................................21
PSD Preliminary Determination Page ii

SUMMARY

The Environmental Protection Division (EPD) has reviewed the PCS Nitrogen Fertilizer – Augusta Plant (PCS 

Nitrogen) application for a permit for the construction and operation of modifications at the facility located in 

Augusta, Georgia. The plant produces ammonia, nitric acid, urea, carbon dioxide, ammonium nitrate, and 

urea-ammonium nitrate solutions. The proposed physical changes will be to the C-002 Nitric Acid Plant.

The current production rate at the C-002 Nitric Acid Plant is limited by air flow rate and pressure equipment 

restrictions. The modifications will allow the plant to increase acid production rate by operating at a higher air 

flow rate and slightly higher pressure. The pre-modification acid capacity is 430,700 tons per year. The 

modification will add the ability to produce an additional 120 tons per day of nitric acid. After completion of 

the project the plant will operate at a total capacity of 474,500 tons per year of 100% nitric acid (1,300 tons per 

day). A portion of the additional nitric acid resulting from the proposed project will be sent to the C-002 

Ammonia Nitrate (AN) Neutralizer. The C-001 Nitric Acid Plant will be unaffected by the proposed 

modifications.

The modifications proposed in the PSD application are physical changes to several C-002 Nitric Acid Plant 

systems including multiple components of the air compressor system, inlet air cooler, air heater, air / ammonia 

mixer, converter elbow, and turbine gas heater. The facility will also install a new waste heat boiler, tail gas 

heater, platinum filter, oxidation vessel, low-pressure water heat boiler, cooler condenser, and absorber. The 

air compressor system upgrades include a cooler for air entering the air compressor, upgrading the current air 

compressor, replacement of the intercooler, upgrading the tail gas expander, rerouting utility steam to the 

turbine, upgrading the surface condenser, upgrading the cooling towers, and installing a supplemental air 

supply.

PCS Nitrogen controls NOX emissions from the nitric acid process with a Non-Selective Catalyst Reduction 

(NSCR) combustor (Source Code AP07), which reduces NOX to elemental nitrogen, CO2, CO, and water. PM 

emissions from the C-002 AN Neutralizer are controlled with a venturi scrubber (Source Code VS02). The 

proposed modifications will result in increased PM, SO2, NOX, CO, and VOC emissions.

PCS Nitrogen will continue to operate a continuous emissions monitoring system (CEMS) for the C-002 Nitric 

Acid Plant to monitor NOX. The facility will also continue to monitor the venturi scrubber pump pressure, 

scrubbant flow rate, and sump concentration for control of PM and opacity from the C-002 AN Neutralizer. 

The facility will install a new CEMS to monitor CO from the C-002 Nitric Acid Plant.

PCS Nitrogen is located in Richmond County, which is classified as “attainment” or “unclassifiable” for SO2, 

PM10, NOX, CO, and ozone (VOC) in accordance with Section 107 of the Clean Air Act, as amended August 

1977.

The EPD review of the data submitted by PCS Nitrogen related to the proposed modifications indicates that 

the project will be in compliance with all applicable state and federal air quality regulations.

It is the preliminary determination of the EPD that the proposal provides for the application of Best Available 

Control Technology (BACT) for the control of NOX and CO, as required by federal Prevention of Significant 

Deterioration (PSD) regulation 40 CFR 52.21(j).

It has been determined through approved modeling techniques that the estimated emissions will not cause or 

contribute to a violation of any ambient air standard or allowable PSD increment in the area surrounding the 

facility (the nearest Class I area is located 230 km from the facility). It has further been determined that the 

proposal will not cause impairment of visibility or detrimental effects on soils or vegetation. Any air quality 

impacts produced by project-related growth should be inconsequential.

This Preliminary Determination concludes that an Air Quality Permit should be issued to PCS Nitrogen 

Fertilizer – Augusta Plant for the construction and operation of the modifications to the C-002 Nitric Acid 

Plant. Various conditions have been incorporated into the current Title V operating permit to ensure and 

confirm compliance with all applicable air quality regulations. A copy of the draft permit amendment is 

included in Appendix A.
PSD Preliminary Determination Page 1

1.0 INTRODUCTION

On January 2, 2003, PCS Nitrogen submitted an application for an air quality permit for modifications to 

the C-002 Nitric Acid Plant. The modifications will be made at the plant located at 733 Laney Walker 

Blvd Extension, Augusta (Richmond County), Georgia. The plant currently produces ammonia, nitric 

acid, urea, carbon dioxide, ammonium nitrate, and urea-ammonium nitrate solutions. The application was 

considered complete on February 11, 2004.

PCS Nitrogen is located in an attainment area for all criteria pollutants. Any proposed project at the plant 

is therefore required to undergo a PSD applicability analysis in order to determine if the project triggers a 

PSD review for any pollutant. If a plant’s operation is listed as one of 28 industrial categories specified in 

the PSD regulations and emits more than 100 tons per year of a PSD pollutant, the plant is considered a 

major source. Nitric acid plants fall under the list of 28 industrial categories and PCS Nitrogen emits in 

excess of 100 tons per year of NOX. The facility is therefore considered a major source under the PSD 

program. As a major source, any project that results in a significant increase of any PSD regulated 

compound triggers a PSD review. The first step in determining if a PSD increase occurs is to calculate 

actual emissions for the two year period before the construction project (2000/2001) and compare this 

result to the future potential emissions after the completion of the project.

Affected Units

The C-002 Nitric Acid Plant has a single emission point. The PSD applicability analysis must also 

include any emission sources elsewhere in the facility that may be debottlenecked by the proposed 

project. The additional nitric acid that will result from the proposed project will normally be sent to the 

C-002 Ammonia Nitrate (AN) Neutralizer, which is a source of particulate matter. The resulting increase 

in particulate matter emissions from the C-002 AN Neutralizer is included in the PSD applicability 

analysis.

Based on the proposed project, the estimated incremental increases of regulated pollutants from the 

facility are listed in Table 1.

Table 1: Emissions Increases from the C-002 Nitric Acid Plant Modification Project

Pollutant Potential Emissions Increase

(tpy)

PSD Significant Emission Rate

(tpy) Subject to PSD Review

PM10* 14.8 15 No

PM* 14.8 15 No

SO2 0.027 40 No

NOX 297 40 Yes

CO 1,452 100 Yes

VOC 10.3 40 No

*All particulate matter was assumed to be PM10 in order to calculate a conservative emissions analysis. The 

particulate matter quantified here includes filterable and condensible particulate matter.

Emissions of NOX from the C-002 Nitric Acid Plant were based on NOX stack testing that was completed 

on the unit during the baseline period. A deminimus amount of NOX also comes from equipment leaks, 

truck loading, rail car loading, and the nitric acid tanks. Small amount of emissions of volatile organic 

compounds (VOC), sulfur dioxide (SO2), and particulate matter (PM) from the C-002 Nitric Acid Plant 

are associated with the combustion of natural gas. Emissions of SO2 and PM are based on AP-42 

emission factors for natural gas combustion. Emissions of CO and VOC are based on previous stack 

testing and natural gas usage during the baseline period. The only other emissions source included in the 

PSD applicability analysis is the C-002 AN Neutralizer, which is a source of PM emissions. PM 

emissions from this source were estimated based upon stack test results.
PSD Preliminary Determination Page 2

Table 2 details the emissions summary for the individual equipment effected by the modification. The 

calculations for the C-002 Nitric Acid Plant and the C-002 AN Neutralizer can be found in detail in the 

facility’s PSD submittal (see Exhibit A of Application No. 14213). These calculations have been 

reviewed and approved by the Division.

Table 2: Net Change in Emissions Due to the Major PSD Modification

Annual Emissions (tpy)

PM / PM10 SO2 NOX CO VOC Source Past 

Actual

Future 

Potential

Past 

Actual

Future 

Potential

Past 

Actual

Future 

Potential

Past 

Actual

Future 

Potential

Past 

Actual

Future 

Potential

C-002 

Nitric Acid 

Plant Stack

1.31 1.65 0.104 0.130 210 507 5,666 7,118 65.95 76.22

C-002 AN 

Neutralizer 36.6 51.0 -- -- -- -- -- -- -- --

Source PM10 SO2 NOX CO VOC

Net 

Increase 14.8 0.027 297 1,452 10.3

Significance 

Level 15 40 40 100 40

PSD 

Applicable? No No Yes Yes No

As Table 2 shows, the modification to the C-002 Nitric Acid Plant will result in an increase in PM/PM10, 

SO2, and VOC emissions below the PSD significance level. As specified per Application No. 14213, the 

modification is classified as a major modification under PSD because the emissions increase for NOX is 

greater than 40 tpy and the increase for CO is greater than 100 tpy.

The facility has proposed to accept a federally enforceable limit of 507 tpy NOX (2.14 lb NOX per ton 

100% nitric acid) for the C-002 Nitric Acid Plant. This requirement limits the maximum net increase in 

NOX emissions to 297 tpy. The facility will comply with this long-term limit in conjunction with a shortterm BACT limit of 3.0 lb NOX per ton of 100% nitric acid. It should be noted that this is the same 

standard set by 40 CFR 60 Subpart G. The facility has also proposed to accept a federally enforceable 

limit 30.0 lb of CO per ton of 100% nitric acid. Compliance will be determined on a 12 month rolling 

average. This requirement limits the maximum net increase in CO emission to 1,452 tpy.

Non-Affected Units

The only other emission source from the process is particulate from the two ammonium nitrate prill 

towers and the associated prill processing equipment. PCS currently operates these units at their 

maximum capacity; therefore any additional nitric acid that will be generated as a result of the proposed 

project will be manufactured into liquid ammonium nitrate solutions. Because the proposed project will 

not affect utilization of the prill towers they are not included in the PSD applicability analysis. Also, the 

nitric acid storage tanks are potential sources of a small amount of nitric acid emissions; however, these 

tanks are controlled by an acid vent recovery scrubber system.

The C-002 Nitric Acid Plant is currently a net exporter of steam. The plant conducted an assessment of 

the proposed changes, which include modifications to the steam system (not to the boilers themselves), 

and concluded that the plant will continue to be a net exporter of steam after the completion of the project. 

As a result the project will not result in an increased utilization of the utility boilers and, in fact, could 

potentially reduce emissions from the utility boiler although no credit is taken for a reduction.

Other than air, the major raw material in the nitric acid production process is ammonia. PCS Nitrogen’s 

ammonia plant operates at its maximum capacity and still does not meet the demand for the other units so 

ammonia is purchased. Therefore, the increase in ammonia demand will be met through additional offsite purchases and will not affect emissions from the on-site ammonia production operations.
PSD Preliminary Determination Page 3

Through its new source review procedure, EPD has evaluated PCS Nitrogen’s proposal for compliance 

with State and Federal requirements. The findings of the EPD have been assembled in this Preliminary 

Determination.

2.0 PROCESS DESCRIPTION

Nitric Acid Manufacturing Process

PCS Nitrogen operates two nitric acid plants, C-001 Nitric Acid Plant and C-002 Nitric Acid Plant. The 

proposed project involves changes to only the C-002 Nitric Acid Plant, the newer of the two plants. The 

production of nitric acid occurs in three steps: ammonia oxidization, nitric oxide (NO) oxidation, and 

NO2 absorption.

The process begins with the compression of ambient air in a two-stage compressor. An intercooler 

between the two stages allows for temperature reduction and improved compression. A steam turbine and 

tail gas expander provide the mechanical energy used for the air compression. The steam for the turbine 

is currently provided by a waste heat boiler via superheater.

The compressed air is then combined with ammonia in a mixer. The mixed ammonia -air mixture is 

routed to a converter reactor where the gases cross a platinum catalyst mesh that oxidizes ammonia to 

NO. Due to the high cost of the catalyst used in this operation a filter is installed downstream of the heat 

exchangers to collect platinum that has been removed from the catalyst mesh. The oxidization process is 

an exothermic reaction and some of the heat generated is recovered in the waste heat boiler and two tail 

gas heat exchangers. The tail gas heat exchangers transfer heat from the process gas to the tail gas, which 

is exiting the nitric acid production process.

The gases next enter an oxidation vessel, which further oxidizes the NO to NO2. The low-pressure waste 

heat boiler recovers additional heat generated in this oxidation step. Next, the NO / NO2 goes through a 

cooler condenser to lower the temperature of the gases. A nitric acid solution is also condensed out. The 

gases exit the cooler and are routed to the bottom of an absorber where they travel up through vertic ally 

stacked trays. Water runs countercurrent from the top of the absorber and reacts with NO2 to form nitric 

acid. The formation of nitric acid results in the formation of NO that must be reoxidized to NO2 prior to 

being absorbed. For this reason, cooled air is also added to the bottom of the absorber to aid in the 

oxidation that occurs between the individual trays in the absorption column. The nitric acid is collected at 

the bottom of the absorber column and sent to a storage tank.

The gases exiting the absorber go through several steps aimed at the reduction of any residual NOX

emissions and the recovery of energy from the tail gas. This includes a mist eliminator to remove any 

remaining liquid in the stream, a tail gas pre-heater, and other heat exchangers for recovery of heat from 

the ammonia oxidation steps. Natural gas is then mixed with tail gas prior to entering a steam 

superheater.

After the superheater, the gases enter a Non-Selective Catalyst Reduction (NSCR) combustor where 

several chemical reactions take place to reduce the NOX in the exhaust gas. The oxygen and natural gas 

are combusted, and secondly, the NOX and natural gas are reacted. The products of these reactions are 

elemental nitrogen, CO2, CO, and water.

When the cleaned gases exit the combustor, they are routed through a tail gas expander to generate 

mechanical energy that is used to operate the air compressor. The gas exiting the expander is routed 

through two heat exchangers to recover any residual heat prior to being vented to the atmosphere through 

Stack ST-19.
PSD Preliminary Determination Page 4

C-002 AN Neutralizer Process

The nitric acid from the C-002 Nitric Acid Plant is first reacted with ammonia vapor in the first stage 

neutralizer. The liquid from the first stage neutralizer overflows into a second stage neutralizer where 

additional ammonia is added. The gases from the first stage vent to a venturi scrubber. The scrubber is in 

place to collect any ammonium nitrate particulate matter that is emitted from the first stage. The liquid 

ammonium nitrate solution exiting the neutralizer goes to a buffer tank prior to being sent to the solutions 

blending plant or one of the two prill towers.

Project Description

The proposed project involves modifying several systems in the C-002 Nitric Acid Plant in order to 

increase the pressure rating of the system and thereby increase the air flow through the system. This air 

flow determines the amount of nitric acid produced. The amount of air flow rate is limited by the air 

compression system and the pressure rating of the equipment in the plant. System pressure is the limiting 

factor during the winter months and the air-compression system is the limiting factor during the summer 

months.

PCS Nitrogen will be installing an air cooler for the ambient air entering the air compressor. The air 

cooler will drop the temperature of the air entering the air compressor and thereby allow for increased air 

throughput and thereby increase production. The intercooler, which is part of the main air compressor, 

will be replaced with an improved design that will solve current leakage problems and slightly improve 

performance.

PCS Nitrogen also plans modifications to increase power from the steam turbine for additional air 

compression. This will include physical modifications to the turbine itself as well as the rerouting of 

steam from the utility boilers to the steam turbine. Currently, steam from the nitric acid plant boiler and 

steam superheater is routed to the steam turbine. However, by utilizing superheated steam directly from 

the utility boilers, which is at a higher temperature, the plant will be able to generate additional 

compression from the steam turbine. The lower temperature superheated steam generated at the C-002 

Nitric Acid Plant will be utilized at other areas of the site. The surface condenser and cooling tower at C002 Nitric Acid Plant will be upgraded to meet the additional cooling demands.

Finally, PCS Nitrogen plans to install a separate air supply entering directly at the absorber. Currently, 

this air stream is supplied by the main air compressor, and therefore utilizes some of the available 

compressor capability. By utilizing a separate air supply for this air stream, the plant can utilize the entire 

capacity of the existing compressor to compress air that enters the heat train and thereby increase 

production. 

PCS Nitrogen also plans to replace the air heater, the ammonia / air mixer, the converter elbow, the 

turbine gas heater, waste heat boiler, the tail gas heater, the platinum filter, the oxidation vessel, the low 

pressure waste heat boiler, the cooler condenser, the absorption tower, and non-selective catalytic 

reduction combustor. All of these modifications will allow the units to operate at a higher pressure.

Neither the utility boilers or the ammonia plant at the site will be debottlenecked by the proposed 

expansion of the C-002 Nitric Acid Plant. The C-002 Nitric Acid Plant is a net exporter of steam, thus 

the project will not increase steam demand for the site. Instead the boiler load at the site should decrease 

due to these proposed modifications. PCS operates an ammonia production plant on site; however, it is 

currently operating at a maximum capacity. Additional ammonia demand will therefore be met through 

purchased ammonia.
PSD Preliminary Determination Page 5

As required by 40 CFR 60 Subpart G, and to assure compliance with the BACT/PSD permit limits, PCS 

Nitrogen will continue to monitor NOX emissions from the C-002 Nitric Acid Plant. The facility is also 

required to develop a conversion factor through performance testing for calculating pounds NOX per ton 

100% nitric acid from the CEMS output. This information, along with production rate data, will allow 

the facility to calculate the 12-month rolling total. The facility will use the same CEMs / conversion 

factor strategy for monitoring the emissions of CO.

3.0 REVIEW OF APPLICABLE RULES AND REGULATIONS

State Rules

Georgia Rule (b) [391-3-1-.02(2)(b)] and Georgia Rule (e) [391-3-1-.02(2)(e)] are general rules limiting 

the opacity and PM emissions from the C-002 AN Neutralizer. Georgia Rule (b) limits the opacity of 

emissions from the unit to 40%. Georgia Rule (e), commonly known as the process weight rule, limits 

PM emissions based on either of the following equations:

For P 3 30 ton/hr, E = 4.1P0.67

For P > 30 ton/hr, E = 55P0.11 - 40

where E = emission rate (lb/hr) and P = process input rate (ton/hr). The second equation applies to the C002 AN Neutralizer.

Federal Rule - PSD

The regulations for PSD in 40 CFR 52.21 require that any new major source or modification of an 

existing major source be reviewed to determine the potential emissions of all pollutants subject to 

regulations under the Clean Air Act. The PSD review requirements apply to any new or modified source 

which belongs to one of 28 specific source categories having potential emissions of 100 tons per year or 

more of any regulated pollutant, or to all other sources having potential emissions of 250 tons per year or 

more of any regulated pollutant. They also apply to any modification of a major stationary source which 

results in a significant net emission increase of any regulated pollutant.

The PSD regulations require that any major stationary source or major modification subject to the 

regulations meet the following requirements:

1. Application of BACT for each regulated pollutant that would be emitted in significant amounts;

2. Analysis of the ambient air impact;

3. Analysis of the impact on soils, vegetation, and visibility;

4. Analysis of the impact on Class I areas; and 

5. Public notification of the proposed plant in a newspaper of general circulation.

Definition of BACT

Sources undergoing a PSD review must apply Best Available Control Technology (BACT) to any new or 

modified emission unit that emits a PSD triggered pollutant. Under 40 CFR 52.21, the federal PSD 

regulations define BACT as “an emission limitation (including a visible emission standard) based on the 

maximum degree of reduction of each pollutant subject to regulation under the Clean Air Act, emitted 

from or which results from any major emitting facility, which the permitting authority, on a case-by-case 

basis, taking into account energy, environmental, and economic impacts and other costs, determines is 

achievable for such facility through application of production processes and available methods, systems, 

and techniques, including cleaning or treatment or innovative fuel combustion techniques for control of 

each such pollutant.” No BACT determination may be less stringent that the applicable NSPS, National 

Emissions Standards for Hazardous Air Pollutants (NESHAPS) or State Implementation Plan (SIP) limits.
PSD Preliminary Determination Page 6

On December 1, 1987, the US EPA Assistant Administrator for Air and Radiation issued a memorandum 

that implemented certain program initiatives designed to improve the effectiveness of the New Source 

Review (NSR) programs within the confines of existing regulations and SIPs. Among these was the “topdown” method for determining BACT. The “top-down” process begins by identifying all available 

control technologies. Next, the technically infeasible options are eliminated. The remaining control 

technologies are then ranked by their control effectiveness. Next, the most stringent or “top” alternative 

is evaluated. This top alternative represents BACT, unless it can be demonstrated, and the permitting 

authority agrees, that technical considerations, energy, environmental, or economic impact justify a 

conclusion that the most stringent technology is not “achievable” in a particular case. If the most 

stringent technology is eliminated in this fashion, then the next most stringent alternative is considered, 

and so on, until the most appropriate control strategy is selected for each source.

Federal Rule – 40 CFR 60 Subpart G

The C-002 Nitric Acid Plant is subject to NSPS Subpart G, Standards of Performance for Nitric Acid 

Plants. Subpart G establishes a NOX emission limit of 3.0 lb NOX per ton of 100% nitric acid produced. 

The Permittee is required to monitor these emissions using a nitrogen oxide CEMS in conjunction with a 

conversion factor (ppm to pounds NOX per ton nitric acid) determined through a performance test 

conducted once every year. The subpart also establishes an opacity limit of less than 10%. No 

monitoring is required for the opacity limit. The NOX emission limit is low enough to keep opacity below 

10%.

Federal Rule – 40 CFR 64

The C-002 Nitric Acid Plant is subject to 40 CFR 64 – Compliance Assurance Monitoring (CAM). CAM 

applies because the plant is located at a major source with a Title V permit, the plant is subject to an 

emission limit, and the facility uses a control device to achieve compliance with the limit. CAM has been 

triggered because the facility is making a significant modification to a unit with potential controlled NOX

emissions of at least 100 percent of the major source threshold. CAM requires the facility to submit a 

plan containing the following information: 1) indicators of emission control performance; 2) indicator 

ranges; 3) performance criteria; 4) indicator ranges and performance criteria for CEMs, COMs, and 

PEMs; 5) monitoring justification; 6) test data, if necessary; and 7) implementation and schedule for 

equipment installation, testing, and other activities, if necessary. The facility has submitted the CAM 

Plant as required and the Division has approved the plan. The facility will continue to monitor NOX

emissions with a CEMs.

4.0 CONTROL TECHNOLOGY REVIEW

The purpose of this section is to provide details of the steps taken in evaluating the “top down” BACT 

analysis for NOX and CO emissions from the C-002 Nitric Acid Plant. Several pieces of process 

equipment in the C-002 Nitric Acid Plant are being physically modified as part of the proposed project. 

All the units operate in series as part of the plant and, in turn, vent through a single emission point.

Nitrogen Oxides (NOX)

The first reaction in the production of nitric acid is the oxidation of ammonia to NO. Next, the NO is 

further oxidized to NO2. The NO2 gases are routed through a water absorber to create nitric acid. A 

portion of the NOX gases are not absorbed and exit the control device. These gases must be treated to 

reduce emissions of the unreacted NOX released to the atmosphere.
PSD Preliminary Determination Page 7

Step 1: Identify all control technologies

There are two NOX emission reduction technologies that are utilized at nitric acid plants. These 

technologies are non-selective catalyst reduction (NSCR) and selective catalytic reduction (SCR). The 

PCS Nitrogen C-002 Nitric Acid Plant currently utilizes the NSCR technology for NOX emission control. 

The first step of the BACT analysis was a review of the NOX emission rates that are currently being 

achieved by other nitric acid plants in the industry. These emission rates were determined through a 

review of the EPA BACT / LAER Clearinghouse. In addition, a review of other recently permitted nitric 

acid plants was also completed. The results of this review are summarized in Table 3.

Table 3: Permitted NOX Emission Levels for Nitric Acid Plants Listed in BACT / LAER Database

Plant Location Unit NOX Emissions 

Control Technology

lbs NOX / ton 

100% Nitric Acid

Terra Nitrogen Ltd 

Partnership (1998)

Woodward, 

Oklahoma Nitric Acid Plant SCR 3.0

Arcadian Fertilizer LP –

Geismar Facility (1997)

Geismar, 

Louisiana Nitric Acid Train 4 NSCR 2.14 (primary)3.0 secondary*

Apache Nitrogen Products, 

Inc. (1991) Arizona Nitric Acid Plant NSCR 3.0

Wycon Chemicals (1984) Wyoming Nitric Acid Plant #1

Nitric Acid Plant #2 None Noted 6.0

Wycon Chemicals (1984) Wyoming Nitric Acid Plant #3 Catalytic NOX Abator 3.0

California Ammonia (1981) California Nitric Acid Plant Extended Absorption 

Column

210 ppm (primary)

3.0 (secondary)

*BACT was established at 3 lb/ton for the unit. In addition the plant took a 195 tpy NOX limit (2.14 lb NOX per ton 100% nitric 

acid) for its 500 T/D nitric acid plant in order to comply with the NAAQS.

The control technology options are as follows:

Option 1: Non-Selective Catalytic Reduction (NSCR)

Option 2: Selective Catalytic Reduction (SCR) – Method 1 

(Replacing current NSCR unit with SCR unit)

Option 3: Selective Catalytic Reduction (SCF) – Method 2 

(SCR as add-on controls).

Step 2: Eliminate technically infeasible options

Options 1 and 3 are considered technically feasible. Option 2 is technically infeasible as explained 

below:

Option 2 – Selective Catalytic Reduction (SCR) – Method 1

SCR uses a catalyst bed and ammonia injection to (1) consume the free oxygen in the absorber tail gas, 

(2) convert the NO2 to NO (decolorization), and (3) reduce NO to elemental nitrogen, CO2, CO, and 

water. The catalyst is termed selective because the ammonia preferentially reacts with NOX in the 

absorber tail gas.

Two plants (BP Chemicals in Lima, Ohio which is owned by PCS Nitrogen and El Dorado Nitrogen in 

Baytown, Texas) both utilize only SCR technology and both have a lower NOX emission limit than the 

proposed 3.0 lb/ton short term limit (1.4 lb/ton and 0.38 lb/ton respectively). While these plants represent 

Option 1, it must be noted that these plants are able to achieve these lower levels because they are of a 

more modern design (the BP Chemicals plant was built in 1991 and the El Dorado Nitrogen plant was 

built in 1999), which is crucial in being able to utilize SCR technology. By comparison, the PCS 

Nitrogen project in Augusta, Georgia is a modification of an existing plant built in 1977.
PSD Preliminary Determination Page 8

SCR is most effective at temperatures near 600 °F. Currently, at PCS Nitrogen and other old design 

plants, the gases entering the combustor are roughly 900 °F. Therefore, in order for the SCR to work, the 

temperature of the gases entering the SCR would need to be cooled by roughly 300 °F. This could be 

achieved by bypassing the turbine gas heater and the steam superheater; however, the effect of this 

change would be to derate the heat efficiency of the system. Secondly, the gases entering the combustion 

catalyst are raised to approximately 1250 °F. This increase in energy is removed and utilized in the C002 Nitric Acid Plant tail gas expander. If the inlet temperature of the tail gas expander was 600 °F 

instead of 1250 °F the tail gas expander would be ineffective in supplying power to the air compressor. 

The tail gas expander provides roughly 75% of the horsepower for the air compressor that runs the nitric 

acid plant. This loss in power would therefore have to be made up by some other source. This would 

require a new steam or combustion turbine, which would increase NOX emissions.

On the other hand, plants built around SCR technology are designed to recover heat generated from the 

ammonia and NO oxidation stages to generate steam. This steam is utilized to provide mechanical energy 

in a steam turbine. The steam turbine, in turn, powers the air compressor. In the case of an older plant 

designed around NSCR technology, the excess heat generated in the heat train is utilized to pre-heat the 

gases exiting the absorber prior to entering the combustor. This gas is next routed through the tail gas 

expander to generate mechanical energy. The tail gas expander in turn provides most of the power for the 

air compressor. A steam turbine is used at plants with NSCR technology, but only to power the air 

compressor during startup and to provide a small fraction of the power needing during normal operation. 

In a plant designed with SCR technology, the power to operate the air compressor is provided by the 

steam turbine, where as in the case of NSCR technology based plants, the power to compress the air is 

provided primarily by the tail gas expander and only secondarily by a team turbine. To modify the 

production process so that SCR could be used would require a complete redesign of the existing plant and 

is therefore not considered practical or economical.

Step 3: Rank remaining control technologies by control effectiveness

Table 4: Ranking of Control Technology 

Control Technology Ranking Control Technology Control Efficiency

1 Non-Selective Catalytic Reduction 94.7-99.1%*

2 Selective Catalytic Reduction 97.2%*

*US EPA and BACT Clearinghouse

Step 4: Evaluate most effective controls and document

Option 1 – Non-Selective Catalytic Reduction (NSCR)

NSCR uses a catalyst bed and fuel to (1) consume the free oxygen in the absorber tail gas, (2) convert the 

NO2 to NO (delecolorization), and (3) reduce NO to elemental nitrogen, CO2, CO, and water. This 

process can utilize natural gas, propane, or hydrogen gas as the fuel. PCS Nitrogen utilizes natural gas as 

the primary fuel, however, hydrogen is utilized during startup of the plant.

The facility currently uses this control method, therefore it is feasible for control of the emissions 

following the proposed modifications. According to data taken from the EPA document “Alternative 

Control Techniques Document-Nitric and Adipic Acid Manufacturing Plants”, a review of numerous 

plants utilizing the available control technologies found that on average, NSCR technology NOX control 

efficiency was higher than that of SCR technology control efficiency.

As shown in Table 4-1, there are 5 listed units with NOX BACT limits of 3.0 lb/ton. The Arcadian 

Fertilizer (now PCS Nitrogen) nitric acid plant located in Geismar, Louisiana, has a second NOX permit 

limit of 195 tpy (2.14 lb NOX per ton 100% nitric acid). This limit is lower than its 3.0 lb/ton BACT limit 

on a tpy basis (assuming maximum production) and was taken for modeling compliance purposes.
PSD Preliminary Determination Page 9

PCS proposes to meet a 507 tpy NOX emission limit for the 1,300 tpd plant which is equivalent to the 195 

tpy NOX limit which was taken for the 500 tpd Arcadian Fertilizer plant. The proposed BACT level is 

therefore 3.0 lb/ton along with a 12-month rolling limit of 507 tpy NOX (2.14 lb NOX per ton 100% nitric 

acid). Compliance with both levels will be demonstrated with the existing continuous NOX emissions 

monitor. Because the effectiveness of the NSCR unit is dependent upon the use of natural gas as a 

reducing agent, the reduction in the annual NOX limit may require the increased utilization of natural gas, 

which is accounted for in the emission calculations.

Option 2 – Selective Catalytic Reduction (SCR) – Method 2

The use of SCR technology as an add-on control for the tail gases of the process, rather than a process 

conversion, was considered. The exhaust gases exiting the nitric acid plant are about 300 °F. In order for 

the SCR to be effective, the exhaust temperatures must be about 600 °F. The exhaust gases would 

therefore need to be raised by 300 °F in order for the SCR system to be effective. This temperature rise 

could be achieved through one of two methods: bypassing the economizer or adding a natural gas burner 

to add heat. Either approach would require additional energy consumption that would result in additional 

combustion emissions. A cost analysis was completed in order to determine the potential effectiveness of 

installing an SCR add-on control to the existing NSCR control system. This cost analysis is summarized 

in Table 5.

Table 5: Cost Effectiveness of SCR Retrofit

Variable Value Basis

NOX Emissions at Proposed BACT Level 507 tpy NOX Proposed Annual BACT Level

NOX Emissions at SCR Controlled Level 90 tpy NOX

Based on vendor estimated emissions with SCR (0.38 

lb/ton) and a production rate of 474,500 tpy

NOX Emissions Reduction with Add-on SCR 417 tpy NOX Difference

Total Annualized Cost of SCR

(including additional natural gas costs) $4,330,000/yr Annualized Cost Estimate for Add-on SCR System*

Cost Per Ton NOX Reduction $10,384/ton Divided Annual Costs by Maximum NOX Reduction

*See Exhibit C of the permit application for the cost analysis for the installation of add-on SCR technology.

As shown above the costs associated with installing an add-on SCR to the existing NSCR system well 

exceeds levels which are considered cost effective for the control of NOX. Note that in order to be 

effective, the ammonia to NOX ratio must be greater than stoichiometry (1 to 1). Some of the ammonia 

injected will therefore be emitted unreacted (ammonia slip). It should also be noted that no known nitric 

acid plants operate both NSCR and SCR technologies.

Step 5: Select BACT

Based on the above evaluation, BACT requires the plant to continue to use Non-Selective Catalytic 

Reduction to control NOX from the modified C-002 Nitric Acid Plant.

Conclusion – NOX Control

The Division has determined that PCS Nitrogen’s proposal to use NSCR to minimize NOX emissions 

constitutes BACT. The BACT emission limits have been established as 3.0 lb NOX per ton 100% nitric 

acid and 507 total tons per year of NOX (an annual average of 2.14 lb NOX per ton 100% nitric acid).

Summary – NOX Control Technology Review for the C-002 Nitric Acid Plant

To fulfill the PSD permitting requirements for NOX, a BACT analysis was conducted for the modified 

C-002 Nitric Acid Plant. The BACT selection for the plant is summarized in Table 6. The emission limit 

selected is representative of previous PSD BACT determination levels published in U.S. EPA’s 

RACT/BACT/LAER Clearinghouse (RBLC) for plants of the similar type.
PSD Preliminary Determination Page 10

Table 6: BACT Summary for the Proposed Modified C-002 Nitric Acid Plant

Pollutant Control Technology Proposed BACT Limit Averaging Period

NOX NSCR 3.0 lb NOX per ton 100% nitric acid 3 hours

NOX NSCR 507 tpy NOX (2.14 lb NOX per ton acid) 12 months

Carbon Monoxide (CO)

The CO emissions from the nitric acid plant result from combustion of natural gas in the NSCR 

combustor. This increase in CO is considered justifiable because regionally NOX is of greater concern 

that CO. By injecting natural gas the unit consumes all the available oxygen, and simultaneously but at a 

slower kinetic rate, the NSCR system reduces the natural gas and NOX to nitrogen, CO2, CO, and H2O.

CO emissions from the plant tend to increase in the stoichiometric ratio of natural gas to oxygen and NOX

going to the combustor. For most catalysts, effectiveness degrades slowly over time, requiring an entire 

bed change approximately every two years. Therefore, keeping all other variables constant, NOX

emissions would tend to increase over time if nothing else was done. To counter this effect the amount of 

natural gas fed to the combustor is increased over time, which in turn raises the natural gas stoichiometric 

ratio, and ultimately CO emissions. This effect is represented by the “R-factor,” which governs the 

proper operation of the combustor.

The R-factor is the ratio of the actual amount of natural gas feed to the combustor versus the 

stoichiometric amount of natural gas needed to reduce the NOX to water and elemental nitrogen. The goal 

is to keep the R-factor as close to one as possible. If the factor is less than one then unreacted NOX can 

leave the system and can cause non-compliance with the facility’s short-term limits. A very high R-factor 

can drive NOX emission down, however this condition indicates that too much fuel is being fed to the 

combustor. This can result in higher than necessary CO emissions and wasted natural gas.

The facility conducted a series of performance tests on June 19, 2002. The tests were conducted with the 

guidance of the equipment vendor. The facility monitored NOX, CO, O2, CO2, and natural gas 

concentrations at various combustor conditions which included starving the system of natural gas, normal 

operation, and flooding the system with natural gas. The starvation, normal operation, and flooding 

conditions simulated the beginning, middle, and end of catalyst life. Based on testing conducted on the 

C-002 Nitric Acid Plant, CO emissions ranged from between 3.1 to 43.0 lb CO/ton of 100% nitric acid 

produced, and averaged 27.7 lb per ton of 100% nitric acid during the testing that represented the last 12 

months of operation before the catalyst is replaced. The facility has proposed a BACT limit of 30.0 lb 

CO per ton of 100% nitric acid based on these results.

As with the NOX BACT evaluation, a review of the EPA clearinghouse and the available permits for other 

recently permitted nitric acid plants was performed for CO emission limits. The facility stated that the 

PCS Nitrogen Geismar facility is the only site with CO limits for nitric acid plants. A review of the 

Geismar PSD permit documents shows that the facility netted out for CO during the PSD analysis. The 

net increase was 21.66 tpy. Because the net increase did not equal or exceed the PSD significance 

threshold of 100 tpy a BACT analysis was not performed. In addition, the Division has reviewed the 

EPA BACT / LAER Clearinghouse and no limits for CO emissions from a nitric acid plant were found.

Step 1: Identify all control technologies

No known nitric acid plants operate emission controls for CO emissions. The facility examined the use of 

a Regenerative Thermal Oxidizer (RTO) or a catalytic system for CO control as used in other 

manufacturing industries.

Option 1: Regenerative Thermal Oxidizer

Option 2: Catalytic System

Option 3: Good Design and Operation
PSD Preliminary Determination Page 11

Step 2: Eliminate technically infeasible options

Options 1 and 3 are considered to be technically feasible. Option 2 is technically infeasible as explained 

below:

Option 2 – Catalytic System

At sufficient temperatures, CO can be converted to CO2 across a catalyst. As with an RTO, additional 

oxygen would be required to allow for the conversion of CO to CO2. Discussions with vendors indicate 

that roughly 15% O2 would be required for a catalyst system to be effective. The addition of sufficient air 

to raise the oxygen content to 15% O2 would result in a 2.5 fold increase in the total flow of the exhaust 

stream. This dilution of the exhaust stream of ambient air would drop the temperature of the exhaust 

gases to well below minimum temperatures which are required for a catalyst system to operate (350 °F). 

A catalyst system is not therefore considered technically feasible.

Step 3: Rank remaining control technologies by control effectiveness

Table 7: Ranking of Control Technology 

Control Technology Ranking Control Technology Control Efficiency

1 Regenerative Thermal Oxidizer 40% - 98%

2 Good Design and Operation N/a

Step 4: Evaluate most effective controls and document

Option 1 – Regenerative Thermal Oxidizer

The most common means for CO control is oxidation. Oxidation completes the combustion process by 

converting CO into CO2. The most practical combustion control device for a high flow application would 

be a RTO. In order for the combustion process to occur air would need to be added to the exhaust 

because the NSCR system consumes all available oxygen. The increase in oxygen content would, in turn, 

increase the operating exhaust flow rate and increase the operating costs associated with operating a RTO.

Discussions with RTO vendors indicate that the oxygen content would need to be a minimum of 3% to 

ensure high combustion efficiency in an RTO. To achieve this minimum oxygen level, the RTO would 

need to bleed in an additional 17,000 acfm to the exhaust gas stream, which would result in a total 

exhaust flow rate to be treated of 117,000 acfm.

In order to determine the costs of installing an RTO, an economic evaluation was completed. This 

evaluation was based on the EPA cost estimating spreadsheets for RTOs. This evaluation concluded that 

an RTO sized to handle this exhaust stream would cost roughly $3,900,000 and require roughly 

$1,100,000 in operating costs per year. This would therefore result in a cost of $250 per ton of CO 

reduced.

However, the operation of an RTO or any combustion control device for CO would also create NOX

emissions, which is the pollutant that is originally being abated by the NSCR. It is estimated that an 

increase in NOX of about 30 tpy would result from the installation of a RTO. As shown in Section 6.0 of 

this document, the modeling for CO emissions indicated that concentrations were only about 21% of the 

PSD Significance Level for a 1-hour average and 38% of the significance level on an 8-hour average. No 

additional modeling was required for the pollutant. The modeled NOX concentration did exceed the 

significance level on an annual basis. Further modeling indicated that NOX concentrations were 73.6% of 

the Class II PSD Increment and 77.1% of the NAAQS. Considering the small environmental benefit of 

reducing CO versus the environmental impact of a RTO (increased NOX in an ozone sensitive area), the 

increased energy demands (increased natural gas and electrical usage in the RTO), and moreover because 

this control has never been demonstrated in this process application, the use of a RTO is not considered 

practical for the C-002 Nitric Acid Plant.
PSD Preliminary Determination Page 12

Option 3 – Good Design and Operation

The formation of CO is minimized by proper NSCR combustor design and operation. Good operation 

includes replacing the catalyst as needed and injecting natural gas to the system in the proper amounts.

Step 5: Select BACT

BACT requires that the plant continue to use good design and operation to control CO from the modified 

C-002 Nitric Acid Plant.

Conclusion – CO Control

The Division has determined that PCS Nitrogen Fertilizer’s proposal to use good design and operation to 

minimize CO emissions constitutes BACT. The BACT emission limit has been established as 30.0 lb CO 

per ton 100% nitric acid on a 12 month rolling average.

Summary – CO Control Technology Review for the C-002 Nitric Acid Plant

To fulfill the PSD permitting requirements for CO, a BACT analysis was conducted for the modified C002 Nitric Acid Plant. The BACT selection for the plant is summarized in Table 8. 

Table 8: BACT Summary for the Proposed Modified C-002 Nitric Acid Plant

Pollutant Control Technology Proposed BACT Limit Averaging Period

CO Good Design and Operation 30.0 lb CO per ton 100% nitric acid 12 month rolling average

5.0 TESTING AND MONITORING REQUIREMENTS

Testing Requirements:

The facility will have to conduct performance testing for NOX and CO from the C-002 Nitric Acid Plant. 

The facility will also be required to conduct performance testing for PM emissions from the C-002 AN 

Neutralizer.

Monitoring Requirements:

The Permittee is currently required to monitor NOX emissions from the C002 Nitric Acid Plant using a 

CEMS. This requirement will continue to be applicable. The CEMS will provide a reasonable assurance 

of compliance with the NSPS and PSD permit limits. The facility must also operate the NOX monitor in 

accordance with the CAM Plan.

The Permittee will now be required to monitor CO emissions from the C002 Nitric Acid Plant using a 

CEMS. The CEMS will provide a reasonable assurance of compliance with the PSD permit limit.

The facility will continue to monitor the C-002 AN Neutralizer scrubber. The monitoring data will 

provide a reasonable assurance of compliance with Georgia Rules (b) and (e).

CAM Applicability:

The permit amendment includes the CAM Plan submitted by PCS Nitrogen for monitoring NOX

emissions from the C-002 Nitric Acid Plant. The plan summarizes the CEMS requirements already in 

place at the facility.
PSD Preliminary Determination Page 13

6.0 AMBIENT AIR QUALITY REVIEW

An air quality analysis is required to determine the ambient impacts associated with the construction and 

operation of the proposed modifications to the C-002 Nitric Acid Plant. The main purpose of the air 

quality analysis is to demonstrate that emissions emitted from the proposed modified major stationary 

source, in conjunction with other applicable emissions from existing sources (including secondary 

emissions from growth associated with the new project), will not cause or contribute to a violation of any 

applicable National Ambient Air Quality Standard (NAAQS) or PSD increment in a Class II or Class I 

area. NAAQS exist for NO2, CO, PM10, SO2, Ozone (O3), and lead. PSD increments exist for SO2, NO2, 

and PM10.

A separate air quality analysis is required for each pollutant emitted in an amount over the PSD 

significant emission rate threshold. As was shown in Table 1, NOX and CO are to be emitted in amounts 

over the respective PSD significant threshold. Thus, an air quality analysis must be performed for these 

two air pollutants.

Compliance with any NAAQS is based upon the total estimated air quality, which is the sum of the 

ambient estimates resulting from existing sources of air pollution (modeled source impacts plus measured 

background concentrations) and the modeled ambient impact caused by the applicant’s proposed emission 

increase and associated growth. It is important to note that the air quality cannot be allowed to deteriorate 

beyond the concentration allowed by the applicable NAAQS, even if not all of the PSD increment is 

consumed.

Modeling:

In general, EPD assesses the ambient impact of a source through the use of mathematical dispersion 

models. The models are based on the assumption that the dispersion of pollutants is primarily a function 

of wind speed and direction, atmospheric stability conditions, and the characteristics of the effective point 

discharge of the exhaust plume. To predict ambient air concentrations, the models simulate the plume 

exhausting from the stack, rising a certain distance in the atmosphere, leveling off, and continuing 

downwind over relatively flat terrain. The concentrations of the pollutants are assumed to have Gaussian 

distribution about the downwind axis centerline of the plume.

The modeling was performed with the latest version of the Industrial Source Complex Short-Tem Version 

3 (ISCST3). ISCST3 is a Gaussian plume dispersion model that estimates hour-by-hour ground-level 

concentrations of emissions from an elevated source. The model provides maximum 24-hour and annual 

average concentrations for receptors located on many grid types around the source for various downwind 

distances. The model also takes into account the effect of downwash caused by nearby buildings and 

structures.

The only NOX and CO emission point included in the analysis is the C-002 Nitric Acid Plant stack 

because it is the only source impacted by the proposed project. Stack conditions are not expected to 

change significantly as a result of the project; therefore, the source was modeled as a single stack. The 

emission rate modeled was the difference in the future potential after the project is completed (maximum 

production at the established BACT emission level) minus the emission rate from the C-002 Nitric Acid 

Plant during the baseline period (2000/2001). Baseline emissions were based on the average of the CO 

and NOX stack tests completed during the baseline periods and the average ton/yr production during the 

baseline period. Table 9 summarizes the emission rate and modeling parameters that were used for the 

stack.
PSD Preliminary Determination Page 14

Table 9: Modeled Stack Parameters

Source Location

Parameter UTM 

Northing 

(m)

UTM 

Easting 

(m)

Temp

(K)

Flow Rate

(m/s)

Dia.

(m)

Stack 

Height

(m)

Increase in 

CO Emissions

(g/s)

Increase in 

NOX Emissions

(g/s)

C-002 

Stack 3700684 413532 447 32.83 1.52 21.0 41.77 8.57

For this review of the proposed PCS Nitrogen facility, the models utilized preprocessed hourly 

meteorological data based on surface measurements made in Augusta, Georgia and upper air 

measurements made in Athens, Georgia for the period of 1974-1978. EPA’s Building Profile Input 

Program (BPIP) was used to calculate building dimensions for the required flow vectors for the short term 

ISC model in order to allow for building downwash. The BPIP developed results for 36 possible wind 

directions.

A Cartesian receptor grid was used for the model runs, with receptors spaced at 100 meters along the 

fence line and out to a distance of 1 kilometer from the center of the facility, with receptors spaced at 500 

meters from 1 kilometer to 5 kilometers, and with receptors used in the ISC modeling. Digital Elevation 

Model (DEM) data obtained from the U.S. Geological Survey was used to determine receptor heights 

using the EPA AERMAP computer program. These heights were spot checked against topographic maps 

to ensure program accuracy.

PSD Screening Results:

The PSD regulations establish specific maximum allowable increases in ambient concentrations (or 

increments) for PM10, NOX, and SO2 for all areas in compliance with the NAAQS. All areas of the 

country are categorized as a function of overall use. The regulations were designed to prevent significant 

air quality deterioration by specifying allowable incremental changes in PM10, NOX, and SO2

concentrations within each area category. The area categories are defined below:

Class I – Those areas where almost any deterioration of current air quality is undesirable, and little 

or no industrial development would be allowed (e.g., national parks, wilderness areas).

Class II – Those areas where moderate, well-controlled energy or industrial growth is desired 

without air quality deterioration up to the national standards (all attainment areas not categorized as 

Class I were initially designated Class II).

Class III – Those areas where substantial energy or industrial development is intended, and where 

modest increases in ambient concentrations above Class II increments, but below national 

standards, would be allowed (designation to Class III must follow strict redesignation procedures).

The Richmond County area and all other attainment areas in Georgia not designated as Class I areas are 

Class II areas. No Class I areas are located within 230 km of the PCS Nitrogen site. The first step in the 

air quality analysis was to determine whether the incremental ambient impacts due to the new emissions 

from the project were greater than U.S. EPA-prescribed Modeling Significance Levels. The “significance 

analysis” determined whether PCS Nitrogen could forgo a full-scale impact analysis to demonstrate 

compliance with the NAAQS and PSD Class II Increments for the C-002 Nitric Acid Plant.

The results of the significance analysis for the modified C-002 Nitric Acid Plant are summarized in 

Tables 10 and 11. The impacts due to the total projected emissions of NOX and CO were calculated in 

this analysis using the ISCST3 dispersion model.
PSD Preliminary Determination Page 15

Table 10 shows the modeled concentration increases for CO from the C-002 Nitric Acid Plant following 

the proposed modifications are below the Significant Impact Level. The PCS Nitrogen project can 

reasonably be assumed to have an insignificant impact on the air quality surrounding the plant, and per 

U.S. EPA modeling procedures, no NAAQS or PSD Class II increment analyses are required for CO 

emissions.

Table 10: Results of CO Modeling Significance Analysis

Pollutant Averaging 

Period

PSD Significant 

Impact Level (μg/m3)

Significant Monitoring 

Concentration (μg/m3)

Modeled 

Concentration 

(μg/m3)

Notes

CO 1-Hour 2,000 575 421 No Additional 

Modeling Needed

CO 8-Hour 500 575 192 No Additional

Modeling Needed

As shown in Table 11, modeled concentration increases for NOX from the C-002 Nitric Acid Plant 

following the proposed modifications are above the Significant Impact Level. Additional NAAQS and 

PSD Class II increment analyses are therefore required for NOX. Contributing nearby sources must be 

included in the model.

Table 11: Results of NOX Modeling Significance Analysis

Pollutant Averaging 

Period

PSD Significant 

Impact Level 

(μg/m3)

Significant Monitoring 

Concentration (μg/m3)

Modeled 

Concentration 

(μg/m3)

Notes

NOX Annual 1 14 1.42 Additional Modeling 

Needed

Refined NOX Analysis:

The refined modeling analysis determines compliance with the PSD increment standard and the National 

Ambient Air Quality Standards (NAAQS). In PSD increment modeling, ambient air quality within a 

predetermined Significant Impact Area (SIA) is evaluated through modeling to determine whether or not 

the total emissions from all sources, both onsite and offsite (within a 50-km radius extending outward 

from the SIA), could cause an exceedance of the allowable NOX PSD Increment. The PSD Increment is 

the allowable incremental increase of ground-level concentration of a pollutant over the baseline level. 

The baseline for NOX emissions is the NOX emission level modeled for this area using September 1988 

data.

The NAAQS Model also utilizes all off-site sources as well as PCS Nitrogen sources. Again, ambient air 

quality within the SIA is also evaluated to determine if an exceedance of the NAAQS standard occurs. 

The NAAQS standard is the maximum concentration of a pollutant allowed at ground level.

The first step in the analysis was to determine the project’s maximum Area of Impact (AOI) for NOX

emissions. The AOI’s critical distance is defined as the greatest distance from the facility at which the 

increase in NOX emissions from the screen model exceeds the significant impact level (1 μg/m3for NOX). 

The AOI is defined as the entire area within a radius of the AOI’s critical distance. This evaluation was 

completed for all five years of NOX screen models and is summarized in Table 5-4 of the permit 

application. This analysis determined that the farthest point which exceeds the significant impact level is 

4.35 km from the plant site and occurred during the 1977 mode led year. Figure 5-3 of the permit 

application provides a plot of the results of the 1977 screen model, which identifies the level of 1 μg/m3

NOX concentration and the AOI. Per EPA guidance, all sources located within 50 km of the AOI (54.35 

km) were included in the modeling analysis.
PSD Preliminary Determination Page 16

The AOI includes sources in both Georgia and South Carolina. A request was therefore made for both 

Georgia (EPD) and South Carolina (Department of Health and Environmental Control – DHEC) to 

provide data for NOX emission sources within the project’s area of impact. DHEC provided a current 

emission inventory for all counties located within the project’s area of impact. The inventory identified 

NOX emission rates, stack locations and parameters, as well as the status of each source as a baseline 

source, increment consumer, or increment expander. None of the South Carolina sources were identified 

as increment consumers, therefore the South Carolina off-site sources were only included in the NAAQS 

model.

The impact of these off-site sources on the air quality models is largely determined by the emission rates 

and the distance between the emission source and the PCS Nitrogen plant. The EPA “20D Rule: 

screening technique was utilized to reduce the large number of sources identified by the EPD and DHEC 

to those which could potentially impact the project. The “20D Rule” allows for the elimination of any 

sources for which emissions (tpy) are less than 20 times the distance (km) from the sources to the PCS 

site.

The 20D rule was only applied to sources for NAAQS modeling. All sources identified as increment 

consumers or expanders were included in the PSD increment analysis. Table 5-5 and 5-6 of the permit 

application provide a list of all plants identified by the EPD and DHEC, respectively, which are within the 

projects area of impact and are sources of NOX. The tables identify the total emissions of NOX from each 

site and the distance from the site to the PCS Nitrogen plant. The final column identifies those sites that 

were screened out using the 20D rule. Table 5-7 of the permit application identifies all off site emission 

points in South Carolina and Georgia that were not screened out and are therefore included in the 

NAAQS modeling analysis.

The EPD provided data for NAAQS sources from an EPA database. The data was validated by reviewing 

Title V permit applications and air quality files of the sources located within the area of impact. For the 

PSD increment modeling, the EPD maintains an up to date spreadsheet which identifies all NOX

increment consumers and expanders in the area as well as all data required for modeling. The most recent 

version (August 2002) was used in this analysis. The sources identified in this spreadsheet which are 

within the projects area of impact were included in the PSD increment model. Table 5-8 provides the 

emissions data for the off-site PSD increment consuming sources which are included in the modeling 

analysis.

There are several on-site operations which are sources of NOX emissions other than the C-002 Nitric Acid 

Plant. These sources include the C-001 Nitric Acid Plant, the Ammonia Plant, and three boilers (AB01, 

AB02, and AB03). Table 5-9 of the permit application summarizes the status of each of these sources as 

baseline, PSD increment consumers, and PSD increment expanders.

The BPIP model was also updated to include any downwash impacts site buildings would have on these 

additional on site sources. This additional BPIP model run is included in both the PSD increment and 

NAAQS NOX models.

NOX Class II PSD Increment Modeling:

As shown in Table 12, modeled impacts of NOX are below the PSD increment. Given this, the proposed 

modifications will comply with the PSD Class II increment. The nearest Class I area is located 230 km 

away from the facility, therefore the impacts from the proposed project were not evaluated for the Class I 

PSD increment.

Table 12: Results of Class II PSD Increment Impact for NOX

Pollutant Averaging 

Period

PSD Increment 

(μg/m3)

Modeled Conc. 

(μg/m3)

Notes

NOX Annual 25 18.4 All significant sources within 54.35 km
PSD Preliminary Determination Page 17

NAAQS NOX Modeling:

The NAAQS are established as ambient ceilings applicable to the entire country, and they must be 

attained and maintained. PSD requires that any pollutant that has predicted significant impacts due to the 

modification alone must be evaluated for NAAQS compliance. Table 5 shows that NOX impacts must be 

evaluated further. The ISCST3 model was run including all “significant sources” (as defined using the 20-

D Rule) within 54.35 km of the plant. The background concentration for NOX is 26 ug/m3(annual). This 

concentration has been added to the modeled concentration to determine total impact. Table 13 below 

includes the modeled concentration (including the background concentration) in comparison to the 

NAAQS. As can be seen from the table, the modeled impact is below the associated NAAQS limit.

Table 13: Results of Ambient Air Quality Impact for NOX

Pollutant Averaging 

Period

NAAQS

(μg/m3)

Modeled Conc. 

(μg/m3)

Additional Notes

NOX Annual 100 77.1 All significant sources within 54.35 km

Complex Terrain Analysis:

Complex terrain (areas where the terrain is higher than the lowest stack height) has been identified in the 

areas surrounding the PCS Nitrogen plant. To determine if complex-terrain modeling is necessary for 

these areas, a comparison between the results of the NOX screen modeling analysis in the default mode 

and the simple-terrain mode was performed for the 26 receptors which are above the height of the lowest 

stack and exceeded the NOX significant impact level. This comparison was performed in order to 

determine whether predicted impacts in intermediate terrain areas are controlled by complex terrain 

algorithms or simple terrain algorithms per the EPA guidance on complex terrain modeling – “Complex 

Terrain Modeling Procedures” – May 19, 1999.

The results at each receptor for the default mode and the simple -terrain mode were compared. Exhibit D 

provides the results of this analysis for all 5 years of model runs. At each receptor, the difference 

between the “simple” result and the “default” result was calculated. In all cases were the default value 

exceeds the significant impact level, the difference between the “default” and “simple” case was less than 

the corresponding significance level for NOX (1 μg/m3). This indicates that either the simple -terrain 

algorithm is controlling the analysis or that the complex-terrain modeling algorithm demonstrates 

insignificant impacts at these locations. Based on this information, no further complex terrain modeling 

is necessary.

Georgia Toxics Analysis:

The C-002 AN Neutralizer scrubber is a potential source of both nitric acid and ammonia emissions that 

are considered toxic pollutants under Georgia state toxics policy. The ammonium nitrate neutralizer is 

not being modified as part of this project, but its emissions will increase due to greater throughput. In 

order to assess the air toxics impact on the environment, emissions from the entire plant were included in 

a modeling analysis. The results of these calculations are included in Exhibit A of the report.

Compliance with the toxic program was determined using the “Guideline for Ambient Impact Assessment 

of Toxic Air Pollutant Emissions” – June 21, 1998. The first step was to determine the Ambient Air 

Concentration (AAC) for each of the compounds. Priority is given to inhalation reference concentrations 

(RfC) and Risked Based Air Concentrations (RBAC) which are identified in the EPA IRS database. The 

listed RfC for Ammonia (0.1 mg/m3) was used for the ammonia analysis. Ammonia also has a Short 

Term Exposure level (STEL) of 27 mg/m3, which was also evaluated. Nitric acid was not identified in the 

IRIS database; therefore, its AAC was based on its Occupational Safety and Health Administration 

(OSHA) Time Weighted Average (TWA) of 5 mg/m3 and a STEL of 10 mg/m3.
PSD Preliminary Determination Page 18

The nitric acid TWA was corrected for exposure levels (assuming a continuous operation of 168 hr/wk). 

Per EPD guidance neither of the STELs was adjusted for exposure levels. Next, a safety factor was 

applied depending on the classification of the pollutant as a carcinogen (100 for non-carcinogen, 300 for 

carcinogens). Per EPD guidance a safety factor of 10 was applied to the STELs. Nitric Acid is not 

considered a carcinogen so a safety factor of 100 was applied to the TWA. Table 14 summarizes the 

AAC for each compound. RfC values taken from the IRIS database required no adjustment.

Table 14: AACs for Ammonia and Nitric Acid

Compound Toxicity 

Data

Adjustment for 

Exposure

Safety Factor 

Adjustment

AAC Basis

Ammonia – RfC 0.1 mg/m3 None None 100 μg/m3EPA IRIS Database

Ammonia – STEL 27 mg/m3 None 2,700 μg/m32,700 μg/m3EPA IRIS Database

Nitric Acid – TWA 5 mg/m31.3 mg/m312 μg/m312 μg/m3 OSHA TWA

Nitric Acid – STEL 10 mg/m3 None 1,000 μg/m31,000 μg/m3 OSHA STEL

Next, The EPA Screen 3 model was run for the source with the shortest stack (C-002 Nitric Acid Plant). 

A copy of the model results is included in Exhibit E of the permit application. The results for this model 

indicate that at a 1 g/s emission rate the model would result in a worst-case 1-hour concentration of 3.3 

μg/m3. The concentration of ammonia and nitric acid were next determined by multiplying this value 

times the actual emission rate of the specific pollutant in grams/second (55.82 g/s and 1.87 g/s 

respectively) from the entire plant. This analysis demonstrates the worst possible results by modeling all 

emission as coming from the worst-case stack. This result, which is a 1-hour average, was next converted 

to an annual, 24-hour, and 15-minute standard for comparison to the various AACs which were calculated 

using the correction factors (0.08, 0.4, and 1.32 respectively). Table 15 summarizes the results of this 

analysis. As shown, all compounds are below their corresponding AACs; therefore compliance with the 

Georgia toxics programs is confirmed.

Table 15: Maximum Ground Level Concentration Comparison to AACs

Compound MGLC - 1 Hour 

Average (μg/m3)

MGLC for Averaging 

Period (μg/m3)

AAC

(μg/m3)

Percentage of 

Allowable Compliance

Ammonia – RfC 184.1 14.7 100 14.7% Yes

Ammonia – STEL 184.1 243.0 2,700 9.0% Yes

Nitric Acid – TWA 6.2 2.5 12 20.8% Yes

Nitric Acid – STEL 6.2 8.1 1,000 8.1% Yes

Class I Areas:

A review was completed to determine the proximity of Class I areas to the site in order to determine if 

any evaluation of the project’s impact on a Class I area is required. The five closest Class 1 areas are the 

Shining Rock Wilderness, Cape Romain Wilderness, Smokey Mountains National Park, Joyce Kilmer –

Slickrock Wilderness, and the Cohutta Wilderness. Table 16 summarizes the distance between PCS 

Nitrogen and the Class I areas.

Table 16: Distance between PCS Nitrogen and the Class I Areas

Area Distance (km)

Shining Rock Wilderness, NC 230

Cape Romain Wilderness, SC 255

Smokey Mountains National Park, NC 261

Joyce Kilmer – Slickrock Wilderness, NC 283

Cohutta Wilderness, GA 349

Okefenokee Wilderness, GA 384

Wolf Island Wilderness, GA 402
PSD Preliminary Determination Page 19

All Class I areas are beyond 200 km from PCS Nitrogen, therefore no Class I evaluation was completed. 

Also, the Division notified representatives of the National Park Service and Fish and Wildlife Services of 

the emissions associated with the PCS Nitrogen application. No additional information was requested 

from the Division by either service.

Class II Visibility Analysis:

Emissions from certain sources can create visible, defined plumes that are noticeable to the casual 

observer. Therefore, an exhaust plume visibility analysis was performed for this project to assure that the 

emission from the project to not create a noticeably visible plume in a local Class II area of interest, the 

Augusta Regional Airport. No visibility analyses were required for Class I areas.

The primary variables that effect whether a plume is visible or not at a certain location are (1) quantity of 

emissions, (2) type of emissions, (3) relative location of source and observer, and (4) background 

visibility range. For this exhaust plume visibility analysis, an analysis was performed using the latest 

version of the EPA VISCREEN model according to the guidelines published in the Workbook for Plume 

Visual Impact Screening and Analysis.

The default particulate size and density from the VISCREEN model were used for the analysis. In order 

to determine the appropriate wind speed and stability class, an evaluation of meteorological data for the 

Augusta weather station located at the Augusta Regional Airport was completed. The meteorological 

information included the frequency distribution of various dispersion conditions (wind speed and 

stability) for a 5-year set of data (1974 – 1978). The PCS Nitrogen site is located north-northeast of the 

airport, therefore the data was evaluated fro the frequency of wind coming only from that direction.

Table 17 below shows the results from the frequency distribution evaluation for the Augusta area weather 

data. The table lists each of the evaluated dispersion conditions, which are ranked in order of decreasing 

severity. EPA procedures (as outlined in the VISCREEN guide) for defining worst case meteorology for 

Level 1 VISCREEN modeling indicates that the modeled dispersion condition is selected such that the 

sum of all frequencies of occurrence of conditions worse than this condition totals 1 percent (i.e., about 

four days per year).

Table 17: Wind Speed and Stability Class Frequency Distribution from NNE Direction

Dispersion Condition 

(Class, Wind Speed)

Number of 1-Hour Occurrences 

in 5 Years of Data Frequency Cumulative Frequency

F, 1 74 0.00169 0.00169

E, 1 27 0.00062 0.00230

D, 1 26 0.00059 0.00290

F, 2 145 0.00331 0.00621

E, 2 91 0.00208 0.00828

D, 2 123 0.00281 0.01109

F, 3 77 0.00176 0.01285

E, 3 85 0.00194 0.01479

F, 4 3 0.00007 0.01485

The frequency data indicates that the 1% cumulative frequency is not reached until the D, 2 dispersion 

condition is reached in the NNE direction. Therefore, the VISCREEN model was run at a wind speed of 

2 m/s and a stability category of 4, or D. In addition, the PM10 and NOX emission increases associated 

with the expansion project were used as input to the model. As directed in the VISCREEN Workbook, a 

background visual range of 25 km was used for the Augusta area.
PSD Preliminary Determination Page 20

For both views inside and outside the Class II area, calculations are performed by the model for the two 

assumed plume-viewing backgrounds. The VISCREEN model output shows separate tables for inside 

and outside the Class II area. Each table contains several variables: theta, azi, distance, alpha, critical and 

actual plume delta E, and critical and actual plume contrast. These variables are defined as:

1. Theta – Scattering angle (the angle between direction solar radiation and the line of sight). If the 

observer is looking directly at the sun, theta equals zero degrees. If the observer is looking away 

from the sun, theta equals 180 degrees.

2. Azi – The azimuthal angle between the line connecting the observer and the line of sight.

3. Alpha – The vertical angle between the line of sight and the plume centerline.

4. Delta E – Used to characterize the perceptibility of a plume on the basis of the color difference 

between the plume and a viewing background. A delta E of less than 2.0 signifies that the plume 

is not perceptible.

5. Contrast – The contrast at a given wavelength of two colored objects such as plume/sky or 

plume/terrain.

The analysis is generally considered satisfactory of delta E and contrast are less than critical values of 2.0 

and 0.05 respectively, both of which are Class I, not Class II, area thresholds.

The Division has reviewed the VISCREEN results presented in the supplement to the permit application 

dated January 5, 2004 and has determined that the visual impact criteria (delta E and contrast) inside the 

Augusta Regional Airport are not exceeded for the proposed project. Since the project passes the Level 1 

analysis for a Class I area for the Class II area of interest, no further analysis of exhaust plume visibility is 

required as part of this air analysis.

Preconstruction Monitoring:

The PSD regulations require that continuous preconstruction monitoring of regulated pollutants emitted in 

significant amounts be conducted to establish existing air quality concentrations in the vicinity of the 

proposed source or modification. However, no preconstruction monitoring data are required if the 

ambient air quality of the project impact from the source is below a certain de minimis concentration.

In performing this analysis, the maximum impacts for both scenarios are determined to be less than the 

corresponding de minimis concentrations of as shown in Tables 10 and 11. No ambient monitoring study 

will be required by the Division based on this data.

7.0 ADDITIONAL IMPACT ANALYSES

PSD requires an analysis of impairment to visibility, soils, and vegetation that will occur as a result of a 

modification to the facility and an analysis of the air quality impact projected for the area as a result of the 

general commercial, residential, and other growth associated with the proposed project.

Visibility:

Visibility impairment is any perceptible change in visibility (visual range, contrast, atmospheric color, 

etc.) from that which would have existed under natural conditions. Poor visibility is caused when fine 

solid or liquid particles, usually in the form of volatile organics, nitrogen oxides, or sulfur oxides, absorb 

or scatter light. This light scattering or absorption actually reduces the amount of light received from 

viewed objects and scatters ambient light in the line of sight. This scattered ambient light appears as 

haze.
PSD Preliminary Determination Page 21

Another form of visibility impairment in the form of plume blight occurs when particles and lightabsorbing gases are confined to a single elevated haze layer or coherent plume. Plume blight, a white, 

gray, or brown plume clearly visible against a background sky or other dark object, usually can be traced 

to a single source such as a smoke stack.

PCS Nitrogen presented a visibility impact analyses for the expansion project discussed in this 

preliminary determination. The results of these analyses showed that the proposed project should have no 

perceptible impact on visibility within the Class II area of interest, the Augusta Regional Airport.

Soils and Vegetation:

Since ground level concentration of NOX and CO are not expected to increase by a significant degree as a 

result of this project, the impacts on soil and vegetation are predicted to be insignificant. There are 

currently no known adverse impacts on local environment from PCS Nitrogen’s emissions and no 

discernible changes are expected to results from the proposed modifications to PCS Nitrogen’s 

operations.

Growth:

An increase in employment at PCS is not expected as a result of any proposed changes; therefore, there 

will be no permanent impact on the surround community with regard to demographics. All the plant 

modifications will occur on existing operations; therefore no grading will be required. The construction 

phase (being a small modification of an existing process) will not adversely impact air quality in the area.

8.0 EXPLANATION OF DRAFT PERMIT CONDITIONS

The permit requirements for this proposed facility are included in draft Permit Amendment No. 2631-

193-0013-V-01-4.

Section 1.0 Facility Description

The facility description section describes the modification to the C-002 Nitric Acid Plant.

Section 3.0 Requirements for Emission Units

Condition 3.3.5 limits the emission of nitrogen oxides from the C-002 Nitric Acid Plant to 3.0 pounds per 

ton 100% nitric acid and limits opacity from the source to less than 10%. The citation for the condition 

has been updated to include reference to 40 CFR 52.21. The citation is necessary to reflect the results of 

the PSD BACT review for nitrogen oxide emissions from the C-002 Nitric Acid Plant.

Condition 3.3.10 has been added to the permit. The condition limits annual (12 consecutive month 

periods) nitrogen oxide emissions to 507 tons per year. This limit is a result of the PSD BACT analysis 

and represents an annual average of 2.14 pounds NOX per ton 100% nitric acid.

Condition 3.3.11 has been added to the permit. The condition limits the emission of carbon monoxide 

from the C-002 Nitric Acid Plant to an average of 30.0 pound CO per ton 100% nitric acid on a 12 month 

rolling basis. This limit is the result of the PSD review.
PSD Preliminary Determination Page 22

Section 4.0 Requirements for Testing

Condition 4.2.2 has been modified to increase the frequency of nitrogen oxide testing for the C-002 Nitric 

Acid Plant and to require carbon monoxide testing for the C-002 Nitric Acid Plant. Annual performance 

tests for carbon monoxide have also been added to the condition. The tests are to be conducted annually 

due to the variability in carbon monoxide emissions as the effectiveness of the catalyst in the nitrogen 

oxide reduction device is lessened over time.

Condition 4.2.8 has been modified. The condition now requires the facility to calculate a conversion 

factor for converting carbon monoxide readings in ppm to pounds per ton 100% nitric acid in addition to 

calculating a conversion factor for nitrogen oxide tests.

Condition 4.2.11 has been added to the permit. The condition requires the facility to conduct 

performance testing for NOX and CO upon completion of the modifications to the C-002 Nitric Acid 

Plant. The tests are necessary to establish the new conversion factors.

Condition 4.2.12 has been added to the permit. The condition requires the facility to conduct a 

performance test for particulate matter on the C-002 AN Neutralizer following the completion of the C002 Nitric Acid Plant modifications. This test is required because the expansion of the C-002 Nitric Acid 

Plant will allow additional nitric acid to be sent to the neutralizer. The condition allows the facility to 

modify the excursion parameters for the C-002 AN Neutralizer scrubber if necessary.

Section 5.0 Requirements for Monitoring 

Condition 5.2.1.b has been added to the permit. The condition requires the facility to install, calibrate, 

maintain, and operate a carbon monoxide CEMS for the C-002 Nitric Acid Plant. The data recorded, in 

addition to the conversion factor determined in accordance with Condition 4.2.8, will be used to 

determine compliance with the PSD limit in Condition 3.3.11 of the permit.

Condition 5.2.2.e has been added to the permit. The paragraph requires the facility to continuously 

monitor nitric acid production rate. This information is necessary to calculate the NOX and CO 

emissions.

Conditions 5.2.5 and 5.2.6 have been added the to permit. The conditions describe the CAM 

requirements for the C-002 Nitric Acid Plant.

Section 6.0 Other Recordkeeping and Reporting Requirements

Condition 6.1.7.a(3) has been added to the permit. The condition defines as an excess emission any 12 

consecutive month period during which the nitrogen oxides emission from the C-002 Nitric Acid Plant 

exceeds 507 tons. 

Condition 6.1.7.a(4) has been added to the permit. The condition defines as an excess emission any 12 

consecutive month period during which average carbon monoxide emissions from the C-002 Nitric Acid 

Plant exceeds 30.0 pounds CO per ton 100% nitric acid.

Condition 6.2.15 has been added the permit. The condition requires the Permittee to calculate and keep 

on record the monthly and 12-month rolling totals for the emission of NOX from the C-002 Nitric Acid 

Plant. These records are necessary to determine compliance with the PSD limits found in Condition 

3.3.10.
PSD Preliminary Determination Page 23

Condition 6.2.16 has been added the permit. The condition requires the Permittee to calculate and keep 

on record the average CO emissions (pounds per ton 100% nitric acid). The records should also include 

the 12-month rolling average. These records are necessary to determine compliance with the PSD limits 

found in Condition 3.3.11.

Condition 6.2.17 has been added to the permit. The condition requires the Permittee to commence 

construction of the proposed modifications within 18 months of the effective date of the permit 

amendment. This is a requirement of PSD.

Section 8.0 General Provisions

Conditions 5.1.1., 7.1.1, 7.2.1, 7.10.1, 8.2.1, 8.5.1, 8.5.3, 8.8.3, 8.10.1, 8.11, 8.14, 8.17.1, 8.20.1, and 8.22 

have been modified. The conditions have been updated to reflect changes to the permit template.

Conditions 8.23, 8.24, 8.25, and 8.26 have been added to the permit. The conditions are now included in 

all Title V permits and have been included in this permit to bring the template conditions up to date.
PSD Preliminary Determination

APPENDIX A

Draft Revised Title V Operating Permit PCS Nitrogen Fertilizer – Augusta Plant

Augusta (Richmond County), Georgia
PSD Preliminary Determination

APPENDIX B

PCS Nitrogen Fertilizer – Augusta Plant PSD Permit Application and Supporting Data

Contents Include:

1. PSD Permit Application No. 14213, December 30, 2002

2. Visibility Analysis for PSD Permit Application No. 14213, January 5, 2004
PSD Preliminary Determination

APPENDIX C

EPD’S PSD Dispersion Modeling and Air Toxics Assessment Review