# BART Modeling Protocol:

Plant Wansley

Prepared by:

Southern Company Services and ENSR Corporation

for Georgia Power Company

May 2006

## Contents

1.0 Introduction

............................................................................................................................... ................ 1-1

1.1 Objectives

............................................................................................................................... ......... 1-1

1.2 Location of source vs. relevant Class I Areas ................................................................................ 1-1

1.3 Organization of protocol document ................................................................................................. 1-1

2.0 Source description and emissions data ............................................................................................... 2-1

2.1 Unit-specific source data ................................................................................................................. 2-1

3.0 Input data to the CALPUFF model ......................................................................................................... 3-1

3.1 General modeling procedures: ....................................................................................................... 3-1

3.2 Air quality database (background ozone and ammonia) ............................................................... 3-1

3.3 Natural conditions and monthl y f(RH) at Class I Areas ................................................................. 3-1

4.0 Air quality modeling procedures ........................................................................................................... 4-1

4.1 Model selection and features .......................................................................................................... 4-1

4.2 Modeling domain and receptors ..................................................................................................... 4-1

4.3 Technical options used in the modeling ......................................................................................... 4-1

4.4 Light extinction and haze impact calculations ................................................................................ 4-2

5.0 Presentation of modeling results ........................................................................................................... 5-1

Appendix A Basis for Source-Specific Sulfuric Acid Emissions for BART Baseline Case..............A-1

Appendix B Field Observational Information for Secondary Orga nic Aeroso ls ................................B-1

i 050106 Wansley BART Modeling Protocol.doc May 2006

## List of Tables

Table 2-1 Plant Wansley modeling emission parameters ....................................................................... 2-2



## List of Figures

Figure 1-1 Location of PSD Class I Areas in relation to Plant Wansley ................................................... 1-2

ii 050106 Wansley BART Modeling Protocol.doc May 2006

## 1.0 Introduction

1.1 Objectives

The Regional Haze Rule requires Best Available Retrofit Technology (BART) for any BART-eligible source that ‘‘emits any air pollutant which may reasonably be antici pated to cause or contribute to any impairment of visibility” in any mandatory Class I federal area. Purs uant to federal regulations, states have the option of exempting a BART-eligible source from the BART requirements based on dispersion modeling demonstrating that the source cannot reasonably be anti cipated to cause or contribute to visibility impairment in a Class I area. In addition, the Environmental Protection Agency (EPA) has promulgated a rule allowing states subject to the Clean Air Interstate Rule (CAIR) to determi ne that CAIR satisfies the BART requirements for SO 2 and

NO

x for electric generating units (EGUs). Preliminary feedback from the Georgia Environmental Protection Division indicates that they anticipate making the decision that CAIR satisfies BART for SO 2 and NO

x for EGUs. Therefore, this modeling protocol focuses on performing the BART modeling analysis for particulate matter (PM) only.

Units 1 and 2 at Plant Wansley, located near Roopville, which is operated by Georgia Power Company, has been identified as a BART-eligible source. The purpose of this document is to summarize the procedures by which a modeling analysis will be conducted for this source . The modeling procedures outlined will be used to determine whether the source is subject to BART require ments (exemption modeling). If it is determined that the source is subject to BART, then th e procedures will be used to evaluate th e visibility improvement factor in the BART determination step (determi nation modeling). The modeling proc edures are consistent with those outlined in the updated final VISTAS common BART modeli ng protocol (dated December 22, 2005, revision 2 – 3/9/06), available at http://www.vistas-sesarm.org/BART/BAR TModelingProtocol_rev2_9Mar2006.pdf . This source-specific BART modeling protoc ol references relevant portions of the common VISTAS modeling protocol.



### 1.2 Location of source vs. relevant Class I Areas

The Georgia Environmental Protection Division, whic h is in charge of the state’s BART program, has determined that units 1 and 2 at Plant Wansley are BART- eligible for PM. Figure 1-1 shows a plot of Plant Wansley relative to nearby Class I Ar eas. There are five Class I areas within 300 km of the plant: Cohutta, Great Smoky Mountains, Joyce Kilmer, Shinning Rock, and Sipsey. The BART exemption modeling will be

conducted for each of these Class I areas in acco rdance with the referenced VISTAS common BART modeling protocol and the procedures described in this s ource-specific BART modeling protocol. If necessary, visibility improvement modeling for the BART determinati on step will be performed for those Class I areas where the exemption modeling shows a greater than 0.5 deciview impact.



### 1.3 Organization of protocol document

Section 2 of this protocol describes the source emissi ons that will be used as input to the BART exemption modeling and, if necessary, the BART determination modeli ng. Section 3 describes the input data to be used for the modeling including the modeling domain, terrain and land use, and meteorological data. Section 4 describes the air quality modeling procedures and Secti on 5 discusses the presentation of modeling results.

Since all of the references cited are also included in the VISTAS common BART modeling protocol (Section 7.), no additional references section is included in this document. Appendix A and B provide additional

information on the baseline source emissions.

050106 Wansley BART Modeling Protocol.doc May 2006 1-1Figure 1-1 Location of Class I Areas in Relation to Plant Wansley

050106 Wansley BART Modeling Protocol.doc May 2006 1-2

## 2.0 Source description and emissions data

2.1 Unit-specific source data

The emissions data used to assess the visi bility impacts at the Class I areas within 300 km of Plant Wansley is discussed in this section. As noted earlier, indications from the Georgia Environmental Protection Division are that they will issue rules stating that CAIR will suffice for EGU BART for SO 2 and NO

x . Therefore, this protocol focuses only on PM 10 . Since various components of PM 10 emissions have different visibility extinction efficiencies, the PM 10 emissions are divided, or “speciated,” into several components (VISTAS common protocol Sections 4.3.3 and 4.4.2). The VISTAS protoc ol (Section 5.) allows for the use of source-specific emissions and speciation factors or default values from AP-42. The PM 10 emissions and speciation approach to be used for the modeling described in this protocol is indicated in the bullets below. Where default speciation values are used, the data represents a unit where current ( baseline) emission controls include electrostatic precipitators (ESPs) and selective cataly tic reduction (SCR) systems, but no post-combustion SO 2 control equipment exists.

• Total PM 10 is comprised of filterable and condensable emissions.

• Baseline filterable PM 10 emissions are based on the highest stack test for the most recent 3-year period (2003-2005). This stack test is combined wi th the highest 24 hour heat input value for this period from CEMS data to calculate the “maximum 24 hour average emission rate” as required by the VISTAS protocol.

• Filterable PM 10 will be subdivided by size category consistent with the default approach from AP-42 Table 1-1.6, and as noted on pages 41 and 42 of the VISTAS common BART modeling protocol. The AP-42 Table 1-1.6 specifies for the emission controls indicated above that 55.6% of filterable PM 10 emissions is coarse (greater than 2.5 microns in size) and 44.4% is fine. Of the fine portion, 3.7% is elemental carbon and the remainder is inorganic fine particulates (soil).

• Condensable PM 10 consists of inorganic and organic compounds . The inorganic portion is by default

assumed to be H 2 SO 4 , although other non-sulfate inorganic condensables could be present. The organic portion is modeled as secondary organic aerosols.

• Baseline H 2 SO 4 emissions are calculated consistent wi th the method used by Southern Company to derive these emissions for TRI purposes. This approach assumes that the H 2 SO 4 emissions released from the stack are proportional to SO 2 emissions from combustion and are dependent on the fuel type

and the removal of H 2 SO 4 by downstream equipment (i.e., ESP and air heater). For eastern

bituminous coal the baseline H 2 SO 4 release rate is in the range of 0.3 to 0.4% of the SO 2 emissions. Appendix A will provide th e basis for the site-spec ific value used.

• Baseline emissions of secondary organic aerosol s (the remaining portion of condensable PM 10 ) are derived based on the supporting field observational in formation in Appendix A and will be a function of

SO 2 emitted.

In practice, CALPUFF allows for the user to input certain components of PM 10 as separate species and separate sizes, which will result in more accurate wet and dry deposition velocity results and also more accurate effects on light scattering. As noted above, th e particle size distribution information is provided in AP-42 Table 1-1.6, and will be used for the BART ex emption modeling as well as the BART determination modeling, if needed.

Table 2-1 provides a summary of the modeling emi ssion parameters to be used in the BART CALPUFF modeling, consistent with the source emissions data presented in Appendix A for the baseline. All of the

emissions in Table 2-1 were extracted from CEMS data for the 2003 to 2005 period and represent the maximum 24-hour average lb/hr rates (excluding days wher e startup, shutdown, or malfunctions occurred).

050106 Wansley BART Modeling Protocol.doc May 2006 2-1May 20062-2050106 Wansley BART Modeling Protocol.docTable 2-1 Plant Wansley modeling emission parametersLocation UTM(Zone 16 NAD-83)Emissions1Particle Speciation2CaseSource/ UnitUTMEastUTMNorthStackHtBaseElev.DiameterGasExitVel.StackGasExitTemp.SO2NOXPM10Filt.PM10FinePMECCond.PM10H2SO4Organickmkmmftmm/sdeg Klbs/hrlbs/hrlbs/hrlbs/hrlbs/hrlbs/hrlbs/hrlbs/hrlbs/hrPlant Wansley currentBaselineNSUnit 1682,8643,699,209304.87307.632.2430.2197773755450.3392.1174.16.40Note358.2Note3SUnit 1682,8643,699,209304.87307.632.2430.2179751773476.7378.9168.26.20Note3134.1Note3BaselineNSUnit 2682,8643,699,209304.87307.632.2430.2212053854302.6240.2106.73.90Note362.4Note3SUnit 2682,8643,699,209304.87307.632.2430.2195211615341.2235.3104.53.90Note3145.3Note3Plant Wansley future, if BART is required4Control 1Unit 1ÈUnit 1Control nUnit 1ÈControl 1Unit 2ÈUnit 2Control nUnit 2NS = Non-Seasonal Rates (Oct - Apr) S= Seasonal Rates (May - Oct)1SO2and NOxemissions are not BART-applicable for EGU sources in CAIR states, if the state agency agrees with EPA’s interpretation of theBART finalrule. The emissions for SO2and NOxare provided for information purposes, and for reference inthe computation of certain particle species such as H2SO4.2Elemental carbon (EC) and Fine PM are a part of Filterable PM10and H2SO4and Organics are a part of Condensable PM10.3Total Condensable PM10= H2SO4+ Organic. The Organic emission value will be provided later.4This data will be provided later if aBART determination analysis is required.For NO

x and SO 2 the values are directly from CEMS. Filterable PM 10 emissions were calculated using the highest stack test over the 2003 to 2005 period and mu ltiplying these value times the maximum 24-hour average heat input derived from CEMS. These values were then adjusted using AP-42 factors from Table 1.1-

6 that indicate that PM 10 is 67% of total PM for a PC unit with an ESP. PM 10 speciation was then performed as indicated above. Since these units include SCRs, a c onsistent set of seasonal emissions data was developed representing periods with and without SCR operation. For these the maximum 24-hour average rates were extracted from the seasonal (May - Septembe r) and non-seasonal (October - April) CEMS data.

If the BART exemption modeling indicates that a BART det ermination is required, then one or more particulate matter control options will be considered for the modeling to determine visibility im provement from the baseline case. The BART engineering analysis w ill provide the justifications for the selected, technically feasible options and the species-specific control efficiencies. Table 2-1 will be updated to provide the modeling parameters for these feasible options and resubmitted to the Georgia Environmental Protection Division for review. Any site-specific deviations from the default particulate matter speciation guidance would be outlined

at that time.

050106 Wansley BART Modeling Protocol.doc May 2006 2-1

## 3.0 Input data to the CALPUFF model

3.1 General modeling procedures:

VISTAS has developed five sub-regional 4-km CALMET meteorological databases for three years (2001- 2003) (VISTAS common protocol Section 4.4.2). Th e sub-regional modeling domains are strategically designed to cover all potential BART eligible sources with in VISTAS states and all PSD Class I areas within 300 km of those sources (to the nearest edge). The ext ents of the 4-km sub-regional domains are shown in Figure 4-4 of the VISTAS common BART modeling protoc ol. The BART modeling for Plant Wansley will be done using the 4-km subdomain 4.

USGS 90-meter Digital Elevation Model (DEM) files were used by VISTAS to generate the terrain data at 4-km resolution for input to the 4-km sub-regional CALMET run. Likewise, USGS 90-meter Composite Theme Grid (CTG) files were used by VISTAS to generate the land us e data at 4-km resolution for input to the 4-km subregional CALMET run.

Three years of MM5 data (2001-2003) were used by VISTAS to generate the 4-km sub-regional meteorological datasets. See Sections 4.3.2 and 4. 4.2 in the VISTAS common BART modeling protocol for

more detail on these issues.

It is intended that all of the modeling for Plant Wansley wi ll use the 4-km subdomain 4. However, if the results indicate that the modeling could be improved with a CA LPUFF run using a finer grid, then refinements in the modeling procedures will be considered and the Georgia Environmental Protection Division will be asked to approve these refinements.

In the event that a finer grid resolution is used, CALM ET must be rerun. Other modifications to inputs of CALMET would include the extent of the modeling domain, the resolution of the terrain and land use data, and other relevant settings. The same MM5 data and obs ervations as used for the 4-km sub-regional CALMET

simulations would be used. The extent of the modeling domain may need to be changed because of disk space restrictions. The size of the CALMET output is di rectly proportional to the grid resolution of the run. The

domain would be limited to the source and the exclus ive Class I area(s) being assessed with a higher grid resolution, including a 50-km buffer in all directions.

If CALMET needs to be run at even a finer grid resoluti on, then the appropriate model setting/files (specifically the GEO.DAT file) will be modified. A summary of th ese modifications would be provided to the Georgia

Environmental Protection Divi sion for review and approval.



### 3.2 Air quality data base (background ozone and ammonia)

Hourly measurements of ozone from all non-urban moni tors, as generated by VISTAS and available on the VISTAS CALPUFF page on the Earth Tech web site (http://www.src.com/verio/download/sample_files.htm), will be used as input to CALPUFF. For ammonia, the approach recommended by VISTAS will be followed. However, since only PM emissions are being modeled, ozone and ammonia data is not really needed given

that this data has no affect on PM results in CALPUFF.



### 3.3 Natural conditions and mont hly f(RH) at Class I Areas

For each of the applicable Class I areas, natural bac kground conditions must be established in order to determine a change in natural conditions related to a s ource’s emissions. The modeling described by this protocol document intends to use annual average natura l background light extinction (EPA 2003 values).

050106 Wansley BART Modeling Protocol.doc May 2006 3-1To determine the input to CALPUFF, it is first necessa ry to convert the deciviews to extinction using the equation:

Extinction (Mm-1) = 10 exp(deciviews/10).

For example, the EPA guidance document indicates for Great Smoky Mountains National Park that the deciview value for the average of the days is 7.60. This is equivalent to an ex tinction of 21.38 inverse megameters (Mm-1).

This extinction includes the default 10 Mm-1 for Ra yleigh scattering. The remain ing extinction is due to naturally occurring particles, and should be held constant fo r the entire year’s simulation. Therefore, the data provided to CALPOST for Great Smoky Mountains woul d be the total natural background extinction minus 10 (expressed in Mm-1), or 11.38. This is most easily input as fine soil concentrations (11.38 μ g/m3) in CALPOST, since the extinction effi ciency of soil (PM-fine) is 1.0 an d there is no f(RH) component. The concentration entries for all other par ticle constituents would be set to zero, and the fine soil concentration would be kept the same for each month of the year. The monthly values for f(RH) that CALPOST needs will be taken from "Guidance for Tracking Progress Under the Regional Haze Rule" (EPA, 2003) Appendix A,

Table A-3.

050106 Wansley BART Modeling Protocol.doc May 2006 3-2

## 4.0 Air quality mo deling procedures

This section provides a summary of the modeling procedur es outlined in the VISTAS pr otocol that will be used for the refined CALPUFF analysis to be conducted for Plant Wansley.



### 4.1 Model selection and features

As noted in the VISTAS protocol (Summary, Reco mmendations Section II.), VI STAS will use CALPUFF Version 5.754 and CALMET Version 5.7, which can be obtained at http://www.src.com/verio/download/download.htm#VISTAS_VERSION . These versions contain enhancements funded by the Minerals Management Servic e (MMS) and VISTAS. They were developed by Earth Tech, Inc. and they are maintained on Earth Tech’s Atmospheric Studies Group CALPUFF website for public access. This release includes CALMET, CALP UFF, CALPOST, CALSUM, and POSTUTIL as well as

CALVIEW.

The major features of the CALPUFF modeling system , including those of CALMET and the post processors (CALPOST and POSTUTIL), are referenced in Section 3 of the VISTAS protocol.



### 4.2 Modeling domai n and receptors

The initial Plant Wansley BART runs will use the sub-domain 4, 4-km CALMET data to be supplied by VISTAS, as discussed above. This domain includes all Cl ass I areas within 300 km of the source, plus a 50-

km buffer. If there is the need for a refined analysis with a finer grid, a supplement to this modeling protocol will be provided describing the proposed procedures.

The receptors used for each of the Class I areas are based on the NPS database of Class I receptors, as recommended by the VISTAS common protocol (Section 4.3.3).

The BART exemption modeling will be conducted for Wans ley units 1 and 2 (BART eligible units) for each

Class I area within 300 km of the source. If nece ssary, unit 1 and 2 will each be modeled separately for the visibility improvement modeling for the BART determina tion step for the Class I areas where exemption modeling shows a greater than 0.5 deciview impact.



### 4.3 Technical options used in the modeling

CALMET modeling for the VISTAS-provided 4-km subdomai ns will be performed per the procedures specified in the VISTAS common BART modeling protocol. If it is decided to conduct additional modeling with a finer grid than 4 km, this modeling protoc ol will be updated to specify the te chnical options to be used in the CALMET run, in order to allow for state agency review and approval .

For CALPUFF model options, Plant Wansley will follow the VISTAS common BART modeling protocol (Section 4.4.1), which states that we should us e IWAQM (EPA, 1998) guidance. The VISTAS protocol (Section 4.3.3) also notes that building downwash effects are not required to be included unless the state

directs the source to include these effects. Since Plan t Wansley is more than 50 km from the nearest Class I area, building downwash effects will not be included in the CALPUFF modeling.

The POSTUTIL utility program (VISTAS common protocol Section 4.4.2) will be used to repartition HNO3 and NO3 using VISTAS-provided ammonia concentrations derived from previous 2002 CMAQ modeling conducted by EPA or the alternate ammonia concentrations approach recommended by VISTAS, if the CMAQ data is unavailable. As indicated earlier, since only PM em issions are being modeled, the treatment of ammonia

should not have an affect on PM results from CALPUFF.

050106 Wansley BART Modeling Protocol.doc May 2006 4-1

### 4.4 Light extinction and haze impact calculations

The CALPOST postprocessor will be used as prescribed in the VISTAS protocol for the calculation of the impact from the modeled source’s prima ry and secondary particulate matter concentrations on light extinction. The formula that is used is the existing (not the November 2005 revised) IMPROV E/EPA formula, which is applied to determine a change in light extinction due to increases in the particulate matter component concentrations. Using the notation of CALPOST, the formula is the following:

b ext = 3 f(RH) [(NH4)2SO4] + 3 f(RH) [NH4NO3] + 4[OC] + 1[Soil] + 0.6[Coarse Mass] + 10[EC] + b Ray

The concentrations, in square brackets, are in ug/m3 and b ext is in units of Mm-1. The Rayleigh scattering term (b Ray ) has a default value of 10 Mm-1, as recommended in EPA guidance for tracking reasonable progress (EPA, 2003a). However, as recommended in the VISTAS prot ocol (Section 6.2.4), for refined 4-km grid (or smaller) CALPUFF runs, the Rayleigh scattering term will be modified for the specific elevation of the Class I area receptors. The Rayleigh term for estimating natu ral background will also, be adjusted to be consistent with this approach.

The assessment of visibility impacts at the Class I areas will use CALPOST Method 6 (VISTAS common protocol Section 4.3.2). Each hour’s source-caused exti nction is calculated by first using the hygroscopic components of the source-caused concentrations, due to ammonium sulfate and nitrate, and monthly Class I area-specific f(RH) values. The cont ribution to the total source-caused extinction from ammonium sulfate and nitrate is then added to the other, non-hygroscopic com ponents of the particulate concentration (from coarse and fine soil, secondary organic aerosols, and from elemental carbon) to yi eld the total hourly source-caused

extinction.

The BART rule significance threshold for the contribution to visibility impairment is 0.5 deciviews. The VISTAS protocol (Section 4.3.2) indicates that with the use of the 4-km sub-regional CALMET database, a source does not cause or contribute to visibility impairment if the 98th percentile (or 8th highest) day’s change in extinction

from natural conditions does not exceed 0.5 deciviews for any of the modeled years (an added check is: the 22nd highest prediction over the three years modeled should also not exceed 0.5 deciviews for a source to be exempted from a BART determination). Both the 98th percentile (or 8th highest) day's change in extinction from natural conditions for any modeled year and the 22nd highest prediction over the three years modeled will be evaluated. The maximum impact from each method must should not exceed 0.5 deciviews for the source to be exempted from a BART determination.

Figure 4-1 of the VISTAS common BAR T modeling protocol presents a fl ow chart showing the components of that modeling protocol for t he analysis to determine whether a source is subject to BART. Again, it should be noted that the modeling for Plant Wans ley will focus on Subregional Fine-Scale modeling as depicted in the lower half of the figure.

If the exemption modeling demonstrates that Plant W ansley does not cause or c ontribute to visibility impairment, then the source will no t be subject to BART requirements, and no further analysis is needed. Otherwise, the source will proceed to perform BART determination modeling for the baseline and each control option in a similar manner as has been described in this document. This protocol will be supplemented with a

revised Table 2-1 if the source is determined to be subject-to-BART.

050106 Wansley BART Modeling Protocol.doc May 2006 4-2

## 5.0 Presentation of modeling results

The BART exemption and, if necessary, the BART dete rmination modeling results for Plant Wansley will be provided to the state agency in a manner as described in the VISTAS protocol (Section 4.5). A report will be produced that includes the following elements (a s suggested in the VISTAS protocol):

1. A map of the source location and Class I areas within 300 km of the source.

2. For the CALPUFF modeling domain, a table listing all Class I areas in the VISTAS domain and those in neighboring states and impacts from the BART 4-km grid exemption modeling at those Class I areas within 300 km of the source, as illust rated in Table 4-3 of the VISTAS protocol.

3. A discussion of the number of Class I areas with visibility impairment due to source emissions for the 98th percentile days in each year (and the 98th percent ile over all three years modeled) greater than

0.5 dv.

4. For the Class I area with the maximum impact, a discussion of the number of days beyond those excluded (e.g., the 98th percentile for refined analyses) that the impact of the source exceeds 0.5 dv, the number of receptors in the Class I area where the impact exceeds 0.5 dv, and the maximum impact.

5. For any finer grid CALPUFF exemption modeling, re sults for those Class I areas for which impacts of

the source exceeded 0.5 dv in the 4-km initial mode ling. We would report the same type of results as provided for 4-km exemption modeling.

The BART determination modeling will be performed fo r those Class I areas shown in the exemption modeling to exceed 0.5 dv impact. The extent of the BART determination modeling results will depend on the number of technically viable controls identified in the engineeri ng analysis phase of the BART assessment. The results presented will be a comparison of the 98 th percentile value for the baseline and each control strategy derived as is outlined above for the exemption modeling. The same statistics as those mentioned above in Steps 3 and 4 would be provided, and a summary of the relati ve results among all emission scenarios run would be produced.

Additionally, the appropriate electronic files used to conduct the CALPUFF modeling will be submitted on CDROM or DVD media.

050106 Wansley BART Modeling Protocol.doc May 2006 5-1

## Appendix A

Basis for Source-Specific Sulfuric Acid Emissions for BART Baseline Case

050106 Wansley BART Modeling Protocol.doc May 2006 A-1

### Appendix A

Basis for Source-Specific Sulfuric Ac id Emissions for BART Baseline Case

Sulfuric Acid (H2SO4) Emissions

During the combustion of sulfur-containing fuels, a percentage of the SO 2 formed is further oxidized to SO 3

. As the flue gas cools across the air heater, this SO 3 combines with flue gas mois ture to form vapor-phase and/or condensed sulfuric acid (H 2 SO 4 ). The baseline H 2 SO 4 emissions shown in Table 2-1 of this BART modeling protocol were calculated consistent with t he method used by Southern Company to derive these emissions for Toxics Release Inventory (TRI) purposes. This method is documented in a report entitled Estimating Total Sulfuric Acid Emissions from Stati onary Power Plants: Revision 3 (2005) prepared by Keith Harrison and Dr. Larry Monroe (Southern Company Serv ices) and Edward Cichanowicz (Consultant). The approach described in this report assumes that H 2 SO 4 emissions released from th e stack are proportional to

SO 2 emissions from combustion and are dependent on the fuel type and the removal of H 2 SO 4 by downstream equipment (i.e., ESP and air heater).

Since this facility contains post-combustion NOx control (SCR), the baseline sulfuric acid emissions estimate

accounts for the manufacture of H 2 SO 4 through combustion and through further oxidation of SO 2 in the SCR.

Calculated sulfuric acid releases then account for lo ss or removal within the system. The equations below

show how the manufacture and release calculations are made. Table A-1 shows the resulting H 2 SO 4 emissions calculations for the s easonal and non-seasonal periods.

Sulfuric Acid Manufactured from Combustion (EMComb):
EMComb = K x F1 x E2 where,
EMComb = total sulfuric acid manu factured from combustion, lbs/yr K = Molecular weight and units conversion constant = 98.07 / 64.04 * 2000 = 3,063 (98.07 = Molecular weight of sulfuric acid; 64.04 = Molecular weight of SO2; Conversion from tons per year to pounds per year – multiply by 2000.) F1 = Fuel Impact Factor (from the emissions estimating report)
E2 = Sulfur dioxide emission s, tons (from CEMS data).

Sulfuric Acid Released from Combustion (ERComb) ERComb = EMComb x F2 (technology impact factors for air heater and ESP) ERComb = EMComb x (0.49) x (0.49)

Sulfuric Acid Manufactured by SCR (EMSCR)
EMSCR = K * S2 * fs * E2 where, EMSCR = Total sulfuric acid manufactured from SCR, lbs per year
K = Conversion factor = 3063 S2 = SCR catalyst SO2 oxidation rate (specified as a decimal) fs = Operating factor of SCR system, fraction of coal burn when SCR operates E2 = SO2 produced, tons per year

Sulfuric Acid Released from SCR (ERSCR) ERSCR = [EMSCR – (Ks * B * fs * SNH3)] * F2x where, ERSCR = Total sulfuric acid released from SCR, lbs per year EMSCR = Total sulfuric acid manufactured from SCR, lbs per year
Ks = Conversion factor = 3799 B = Coal burn in TBtu/yr

050106 Wansley BART Modeling Protocol.doc May 2006 A-2fs = Operating factor of SCR system, fraction of coal burn when SCR operates SNH3 = NH3 slip from SCR, ppmv at 3% O2 F2x = Technology Impact Factors, all that apply

Total Sulfuric Acid Released (TSAR):
TSAR = ERComb + ERSCR

050106 Wansley BART Modeling Protocol.doc May 2006 A-3Table A-1 Plant Hammond sulfuric acid calculationsCaseSource/ UnitSO2Conv.FactorFuelImpactFactorManuffromCombut.APHFactorESPFactorReleasedFromCombust.SCROxid.RateSCROp.FactorManuf bySCRCoal Burn, BConv.FactorNH3SlipReleas.fromSCRTotalReleasedlbs/hrKF1lbs/hrF2F2lbs/hrS2fslbs/hrTBtu/hrKsSNH3lbs/hrlbs/hrBaselineNSUnit 119776.530630.008242.30.490.4958.20.0130.00.00.0068037990.750.058.2SUnit 117974.930630.008220.20.490.4952.90.0131.0357.90.0068037990.7581.3134.2BaselineNSUnit 221205.230630.008259.80.490.4962.40.0130.00.00.0079137990.750.062.4SUnit 219521.330630.008239.20.490.4957.40.0131.0388.70.0079137990.7587.9145.3NS = Non-Seasonal (Oct - Apr) S= Seasonal (May - Oct)May 2006A-4050106 Wansley BART Modeling Protocol.doc

## Appendix B

Field Observational Information for Secondary Organic Aerosols (To Be Provide Later)

042406 Wansley BART Modeling Protocol.doc April 2006 B-1