2.0 Source description and emissions data 

2.1 Unit-specific source data 

The emissions data used to assess the visibility impacts at the Class I areas within 300 km of Plant Miller are 

discussed in this section. ADEM and JCDH have indicated that CAlR will satisfy BART for EGUs for SO2 and 

NO,. Therefore, this protocol focuses only on PMlo. Since various components of PMlo emissions have 

different visibility extinction efficiencies, the PMlo emissions are divided, or "speciated," into several 

components (VISTAS common protocol Sections 4.3.3 and 4.4.2). The VISTAS protocol (Section 5.) allows 

for the use of source-specific emissions and speciation factors and/or default values from AP-42. The PMlo 

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), but no post-combustion NO, or SO2 control 

equipment exists. 

Total PMlo is comprised of filterable and condensable emissions. 

Baseline filterable PMlo emissions are based on the highest stack test for the most recent 3-year 

period (2003-2005). This stack test is combined with 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 PMlo will be subdivided by size category consistent with the default approach from AP-42 

Table 1-1.6, and as noted on pages 43 and 44 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 PMlo 

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 PMlo consists of inorganic and organic compounds. The inorganic portion is by default 

assumed to be H2S04, although other non-sulfate inorganic condensables could be present. The 

organic portion is modeled as organic aerosols. 

Baseline H2S04 emissions are calculated consistent with the method used by Alabama Power to 

derive these emissions for TRI purposes. This approach assumes that the H2S04 emissions released 

from the stack are proportional to SOn emissions from combustion and are dependent on the fuel type 

and the removal of H2S04 by downstream equipment (i.e., ESP and air heater). For Powder River 

Basin (PRB) coal the baseline H2SO4 release rate is in the range of 0.1 to 0.9% of the SO2 emissions. 

Appendix A provides the basis for the site-specific values used. 

Baseline emissions of condensable organics (the remaining portion of condensable PMlo) are derived 

based on the supporting field observational information in Appendix B and is estimated as 0.32% of 

SO2 emitted. 

Coarse filterable particles (between 2.5 and 10 microns in size) will be modeled with a geometric mass 

mean diameter of 5 microns, while fine filterable and all condensable particles will be modeled with a 

geometric mass mean diameter of 0.48 microns, consistent with the CALPUFF default value for fine 

particles. The geometric standard deviation for both fine and coarse particles will be set to 2 microns, 

consistent with the CALPUFF default value. The 0.48 micron diameter value for fine particles comes 

from the default values in sample input files presented on the TRC web site. There is no default 

value presented for the coarse particles on the TRC web site. However, since 5 is the geometric 

mass mean diameter of 2.5 and 10 (the bounds of coarse particle sizes), it is a reasonable estimate 

for the geometric mass mean diameter for that class of particles. 

In practice, CALPUFF allows for the user to input certain components of PMlo as separate species and 

separate sizes, which will result in more accurate wet and dry deposition velocity results and also more 

082506 Miller BART Modeling Protocol.doc 2- 1 August 2006 
accurate effects on light scattering. As noted above, the particle size distribution information is provided in 

AP-42 Table 1-1.6, and will be used for the BART exemption modeling as well as the BART determination 

modeling, if needed. 

Table 2-1 provides a summary of the modeling emission parameters to be used in the BART CALPUFF 

modeling, consistent with the source emissions data presented in Appendices A and B for the baseline. All of 

the emissions in Table 2-1 were derived from CEMS data for the 2003 to 2005 period and represent the 

maximum 24-hour average Ib/hr rates (excluding days where startup, shutdown, or malfunctions occurred). 

For NO, and SO2 the values are directly from CEMS. Filterable PMlo emissions were calculated using the 

highest stack test over the 2003 to 2005 period and multiplying these values times the maximum 24-hour 

average heat input derived from CEMS. These values were then adjusted using AP-42 factors from Table 1 .l6 that indicate that PMlo is 67% of total PM for a pulverized coal unit with an ESP. PMlo speciation was then 

performed as indicated above such that total Filterable PM10 is made up of Coarse Soil plus total Fine PM and 

total Fine PM is made up of Fine Soil plus Elemental Carbon (EC). Since these units include SCRs, a 

consistent 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 - 

September) and non-seasonal (October - April) CEMS data. 

If the BART exemption modeling indicates that a BART determination is required, then one or more particulate 

matter control options will be considered for the modeling to determine visibility improvement from the baseline 

case. The BART engineering analysis will 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 ADEM and JCDH for review. Any site-specific 

deviations from the default particulate matter speciation guidance would be outlined at that time. 

082506 Miller BART Modeling Protocol.doc August PO06 
Table 2-1 Plant Miller modeling emission parameters 

I Location UTM I 

Source (Zone NAD-27) Actual Base Case I Unit Stack Ht Elev. 

East North 

1 Baseline Data - Current Configuration (Unit Basis) 

Particle speciation2 

Dia- Exit 

meter 1 "el. 1 Filt. Zoarse Fine Fine Condm SO2 N"x P"lo soit PM soif EC H2S04 3rganic PM'~ 

I I I I I I I I I I I I I 

m I mls I deg K I lbdhr I lbdhr I Ibshr Ilbdhr llbslhr Ilbshr llbslhr (ibslhr llbslhr Ilbdhr Ilbshr 

August 2006 
Table 2-2 (Continued) Plant Miller modeling emission parameters 

Notes: 

1 With Alabama being a CAlR affected state, SO2 and NO, emissions are not BART-applicable for EGU sources assuming ADEM and JCDH agree with 

EPA's interpretation of the BART final rule. The emissions for SO2 and NO, are provided for information purposes, and for reference in the computation of 

certain particle species such as H2SO4. 

Elemental carbon (EC) and Fine PM are a part of Filterable PMlo and H2SO4 and Organics are a part of Condensable PMlo. Note that is input to 

CALPUFF as SO4. The molecular weights of H2S04 and SO4 are 98 and 96 respectively; therefore the conversion factor from H2S04 to SO4 is 96/98. 

Actual height since GEP height of 735 ft (224.0 m) is greater than actual height. 

This data will be provided later if a BART determination analysis is required. 

082506 Miller BART Modeling Protocol.doc August 2006 
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). The sub-regional modeling domains are strategically 

designed to cover all potential BART eligible sources within VISTAS states and all PSD Class I areas within 

300 km of those sources (to the nearest edge). The extents of the 4-km sub-regional domains are shown in 

Figure 4-4 of the VISTAS common BART modeling protocol. The BART modeling for Plant Miller 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 use 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 Miller will use the 4-km subdomain 4. However, if the results 

indicate that the modeling could be improved with a CALPUFF run using a finer grid, then refinements in the 

modeling procedures will be considered and ADEM and JCDH will be asked to approve these refinements. 

In the event that a finer grid resolution is used, CALMET 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 observations 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 directly proportional to the grid resolution of the m. The 

domain would be limited to the source and the exclusive 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 resolution, then the appropriate model settinglfiles (specifically 

the GEO.DAT file) will be modified. A summary of these modifications would be provided to ADEM and JCDH 

for review and approval. 

3.2 Air quality database (background ozone and ammonia) 

Hourly measurements of ozone from all non-urban monitors, as generated by VISTAS and available on the 

VISTAS CALPUFF page on the Earth Tech web site (http://www.src.com/verio/download/samplefiles.htm), 

will be used as input to CALPUFF. For ammonia, a 0.5 ppb background value as recommended by VISTAS 

will be used. However, since only PM emissions are being modeled, ozone and ammonia data is not really 

needed given that this data has no effect on PM results in CALPUFF. 

3.3 Natural conditions and monthly f(RH) at Class I Areas 

For each of the applicable Class I areas, natural background conditions must be established in order to 

determine a change in natural conditions related to a source's emissions. The modeling described by this 

protocol document intends to use annual average natural background light extinction (EPA 2003 values). 

082506 Miller BART Modeling Protocol.doc August 2006 
To determine the input to CALPUFF, it is first necessary to convert the deciviews to extinction using the 

equation: 

Extinction (Mm") = 10 exp(deciviews/l 0). 

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 extinction of 21.38 inverse 

megameters (Mm-I). 

This extinction includes the default 10 Mm-1 for Rayleigh scattering. The remaining extinction is due to 

naturally occurring particles, and should be held constant for the entire year's simulation. Therefore, the data 

provided to CALPOST for Great Smoky Mountains would be the total natural background extinction minus 10 

(expressed in Mm-l), or 11.38. This is most easily input as fine soil concentrations (1 1.38 pg/m3) in CALPOST, 

since the extinction efficiency of soil (PM-fine) is 1.0 and there is no f(RH) component. The concentration 

entries for all other particle 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. 

082506 Miller BART Modeling Protocol.doc August 2006 
4.0 Air quality modeling procedures 

This section provides a summary of the modeling procedures outlined in the VISTAS protocol that will be used 

for the refined CALPUFF analysis to be conducted for Plant Miller. 

4.1 Model selection and features 

As noted in the VISTAS protocol (Summary, Recommendations Section II.), VISTAS will use CALPUFF 

Version 5.754 and CALMET Version 5.7, which can be obtained at 

htt~://www.src.com/verio/download/download.htm#VlSTAS VERSION. These versions contain 

enhancements funded by the Minerals Management Service (MMS) and VISTAS. They are maintained on 

TRC's Atmospheric Studies Group CALPUFF website for public access. This release includes CALMET, 

CALPUFF, 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 domain and receptors 

The initial Plant Miller BART runs will use the sub-domain 4, 4-km CALMET data supplied by VISTAS, as 

discussed above. This domain includes all Class 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 Miller Units 1,2, 3 and 4 (BART eligible units) for each 

Class I area within 300 km of the source (Sipsey and Cohutta). If necessary, Units l,2,3 and 4 will be 

modeled separately for the visibility improvement modeling for the BART determination 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 subdomains 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 protocol will be updated to specify the technical options to be used in the 

CALMET run, in order to allow for state agency review and approval. 

For CALPUFF model options, Plant Miller will follow the VISTAS common BART modeling protocol (Section 

4.4.1), which states that we should use 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 Plant Miller 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 HN03 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 emissions are being modeled, the treatment of ammonia 

should not have an affect on PM results from CALPUFF. 

082506 Miller BART Modeling Protocol.doc August 2006 
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 primary and secondary particulate matter concentrations on light extinction. 

The formula that is used is the existing (not the November 2005 revised) IMPROVEIEPA 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: 

bext = 3 f(RH) [(NH4)2S04] + 3 f(RH) [NH4N03] + 4[OC] + 1 [Soil] + O.G[Coarse Mass] + IO[EC] + b~ay 

The concentrations, in square brackets, are in ug/m3 and beXt is in units of ~m-'. The Rayleigh scattering term 

(bRay) has a default value of 10 ~m", as recommended in EPA guidance for tracking reasonable progress 

(EPA, 2003a). 

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 extinction 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 contribution to the total source-caused extinction from ammonium sulfate and 

nitrate is then added to the other, non-hygroscopic components of the particulate concentration (from coarse 

and fine soil, secondary organic aerosols, and from elemental carbon) to yield 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 should not exceed 0.5 deciviews for the source 

to be exempted from a BART determination. 

Figure 4-1 of the VISTAS common BART modeling protocol presents a flow chart showing the components of 

that protocol for the analysis to determine whether a source is subject to BART. Again, it should be noted that 

the modeling for Plant Miller will focus on Subregional Fine-Scale modeling as depicted in the lower half of the 

figure. 

If the exemption modeling demonstrates that Plant Miller does not cause or contribute to visibility impairment, 

then the source will not 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 and any other source specific adjustments if the source is determined to be subject-to-BART. 

082506 Miller BART Modeling Protocol.doc August 2006 
5.0 Presentation of modeling results 

The BART exemption and, if necessary, the BART determination modeling results for Plant Miller 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 (as 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 illustrated 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 percentile 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, results for those Class I areas for which impacts of 

the source exceeded 0.5 dv in the 4-km initial modeling. We would report the same type of results 

as provided for 4-km exemption modeling. 

The BART determination modeling will be performed for 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 engineering analysis phase of the BART assessment. The results 

presented will be a comparison of the 98'h 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 relative 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. 

082506 Miller BART Modeling Protocol.doc August 2006 
Appendix A 

Basis for Source-Specific Sulfuric Acid Emissions for BART 

Baseline Case 

082506 Miller BART Modeling Protocol.doc August 2006 
Appendix A 

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

Sulfuric Acid (H2S04) Emissions 

During the combustion of sulfur-containing fuels, a percentage of the SO2 formed is further oxidized to SO,. 

As the flue gas cools across the air heater, this SO3 combines with flue gas moisture to form vapor-phase 

andlor condensed sulfuric acid (H2S04). The baseline H2SO4 emissions shown in Table 2-1 of this BART 

modeling protocol were calculated consistent with the method used by Southern Company to derive these 

emissions for Toxics Release Inventory (TRI) purposes. This method is documented in a report titled 

Estimating Total Sulfuric Acid Emissions from Stationary Power Plants: Revision 3 (2005) prepared by Keith 

Harrison and Dr. Larry Monroe (Southem Company Services) and Edward Cichanowicz (Consultant). The 

approach described in this report assumes that H2S04 emissions released from the stack are proportional to 

SO2 emissions from combustion and are dependent on the fuel type and the removal of H2S04 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 H2S04 through combustion and through further oxidation of SO2 in the SCR. 

Also, since this facility contains a flue gas conditioning system on Units 1 and 2, the sulfuric acid emissions 

estimate also accounts for the manufacture of H2S04 through injection of SO3 prior to the ESP. Calculated 

sulfuric acid releases then account for loss or removal within the system. The equations below show how the 

manufacture and release calculations are made. Tables A-1 and A-2 show the resulting H2SO4 emissions 

calculations for the seasonal (SCR operation) and non-seasonal periods. 

Sulfuric Acid Manufactured from Combustion (EMComb): 

EMComb = K x F1 x E2 

where, 

EMComb = total sulfuric acid manufactured from combustion, Ibslyr 

K = Molecular weight and units conversion constant = 98.07 164.04 * 2000 = 3,063 

(98.07 = Molecular weight of sulfuric acid; 64.04 = Molecular weight of S02; Conversion from tons per 

year to pounds per year - multiply by 2000.) 

F1 = Fuel Impact Factor (from the emissions estimating report) 

E2 = Sulfur dioxide emissions, 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, Ibs 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 hour 

Sulfuric Acid Released from SCR (ERSCR) 

ERSCR = [EMSCR - (Ks * B * fs * SNH3)] * F2x 

where, 

ERSCR = Total sulfuric acid released from SCR, Ibs per year 

EMSCR = Total sulfuric acid manufactured from SCR, Ibs per year 

082506 Miller BART Modeling Protocol.doc A-2 August 2006 
Ks = Conversion factor = 3799 

B = Coal burn in TBtuIhr 

fs = Operating factor of SCR system, fraction of coal burn when SCR operates 

SNH3 = NH3 slip from SCR, ppmv at 3% 02 

F2x = Technology lmpact Factors, all that apply 

Sulfuric Acid Manufactured from Flue Gas Conditioning (EMfgc): 

EMfgc=KexBxfexIs 

where, 

EMfgc = total sulfuric acid manufactured from flue gas conditioning system, Ibslhr 

Ke = Conversion Factor = 3,799 

B = Coal burn in TBtuIhr 

fe = Operating factor of FGC system, fraction of coal burned when FGC operates 

Is =SO3 injection rate in ppmv at 6% 02, wet 

Sulfuric Acid Released from FGC (ERfgc) 

ERfgc = [EMfgc - (Ke * B * fe * INH~)] * F3 x F2 

where, 

ERfgc =Total sulfuric acid released from FGC, Ibs per hour 

EMfgc = Total sulfuric acid manufactured from FGC, Ibs per hour 

Ke = Conversion factor = 3799 

B = Coal burn in TBtuIhr 

fe = Operating factor of FGC system, fraction of coal burn when FGC operates 

1~~3 = NH3injection for dual flue gas conditioning system, ppmv at 6% 02, wet (= 0 if no NH3 used) 

F3 = Technology lmpact Factors for FGC 

F2 = Technology lmpact Factors for eaui~ment after ESP onlv 

If no control after ESP, F2 = 1 

Total Sulfuric Acid Released (TSAR): 

TSAR = ERComb + ERSCR + ERfgc[Miller 1 and 2 only] 

082506 Miller BART Modeling Protocol.doc August 2006 
Table A-2 Plant Miller sulfuric acid calculations (Flue Gas Conditioning and Total) 

Case 

- 

- 

- 

- N S 

- S 

- N S 

- S 

- N S 

- S 

- N S 

- S 

Jon 

Conv. FGC 

Factor OP. 

Factor 

SO3 Manuf 

Injection by 

Rate FGC 

Tech 

Impact 

Factor 

for 

FGC 

F3 

Tech 

lmoact 1 NHJ / Released Total 

Released 

Source 1 

Unit 

after ESP 

S= Seasonal 

I 

( 

-- 

F2 I 1~~13 lbslhr lbslhr 

Unit 1 10.1 

Is lbslhr 

Baseline 

Unit 1 

Baseline Unit 2 

Unit 2 

Baseline Unit 3 

Unit 3 

Baseline 

NS = 

Unit 4 

Unit 4 

ieasonal 

nla I nla 

October 1 - Ap 

nla I nla nla I nla I nla 

ay 1 - September 30) 

082506 Miller BART Modeling Protocol.doc August 2006 
Appendix B 

Estimated Emissions of Primary Total Carbon and Primary Sulfate 

From Coa/-F/'ed Power Plants 

[The above titled paper is included as a separate document along with 

this site specific BART modeling protocol. This paper was prepared for 

Southern Company by Eric S. Edgerton of Atmospheric Research & 

Analysis, Inc.] 

082506 Miller BART Modeling Protocol.doc August 2006 
Appendix A 

Discussion of CALPUFF modelinq options used for BART analvses 

Various CALPUFF model options were specified in an EPA memo issued by Dennis Atkinson and 

Tyler Fox of the Office of Air Quality Planning and Standards; the memo was entitled "Dispersion 

Coefficients for Regulatory Air Quality Modeling in CALPUFF", March 16, 2006. Of these various 

recommended settings, Southern Company, upon advice from ENSR, has used alternative 

settings for two specific options: CDIV and MPARTL. The values used by Southern Company 

and the reasons for these uses are provided below. 

CDIV: This parameter affects the divergence criterion for dwldz across puffs used to initiate 

adjustment for horizontal convergence. The value specified in the IWAQM Phase 2 report (1998) 

is 0.01 (Ilsec). Since the time that report was generated, this option in CALPUFF was changed 

by the model developer, Earth Tech, to 0.0 to improve the model performance in the year 2000. 

The use of the smaller value gives better protection against mass accumulation within 

convergence zones by compensating with increased sigma-z to account for vertical movement of 

the air. The model change actually requires two values for CDIV (values at partial and full 

adjustment), and the default value for each was accordingly changed to 0.0. This was confirmed 

by Joe Scire in an email to Bob Paine dated 12/22/06 (a copy can be provided upon request). 

The old default value of 0.01 continues to be erroneously recommended by EPA, however, 

because the 1998 IWAQM guidance was never corrected, and EPA memos such as the Atkinson 

and Fox memo referenced above have not made the correction either. Some states, such as 

Minnesota (see http:l/ww.pca.state.mn.us/air/reuionalhaze.html) as well as Montana and other 

western states are using the current CDIV default values of 0.0, 0.0 in their BART analyses. 

A number of CALPUFF input files provided on the TRC web site have 0.0, 0.0 as the selected 

CDIV values. Due to this reason and the updated default value specification for CDIV, Southern 

Company has elected to use the current default values of 0.0, 0.0. 

MPARTL: This parameter affects the manner in which puffs interact with the mixing lid. A value 

of 0 means that the ISCST3 modeling approach is used; while a value of 1 means that the 

AERMOD approach is used. In the March 16,2006 Atkinson and Fox memo, other AERMODrelated options (some default, some not) that had been accepted before this time were removed 

from the approved list. The MPARTL option was apparently retained (possibly an EPA oversight) 

as set to I in the memo, even though it is an AERMOD feature. A CALPUFF input file provided 

on the official TRC web site for VISTAS BART modeling (as well as the approved general EPA 

version) has MPARTL set to 0, which would be consistent with the rest of the changes affecting 

AERMOD options, and which is the CALPUFF default. Consistent with the other changes 

removing AERMOD-related settings, Southern Company has opted to set MPARTL to zero, the 

CALPUFF default. 
CALPUFF lnput Variables 

CALPUFF Model Input Group 1: General Run Contrnl Parametets 

Parameter 

LCFllES 

NYETD4.T 

N PTDAT 

input Used 

F 

3 6 

0 

Default 

I 

0 

Use- def~ned. also rnodelec 2002 anc 2303 

Use- def~ned 

Use- def~ned. 20152 3rd 2003 = 2 

NARDAT 

N\!DLCAT 

METRUN 

19YR 

13MO 

13DY 

MRESTART 2 o 

NRESPD 24CI 0 

METFM i '1 

Corn~nents 

User def~ned 

Use; def~ned 

Set ,n case of coniputer:sq lesrart 

Use- def~ned 

i] 

13 

83 

200 i 

i. 

0 

c7 

0 
CALPUFF Model Input tiroiiy 2: Technical t3gtions 
I CALPUFF Mcdd Itlput Group ?: Species List-Chemist~y 6jstEons. 

b 

IY 

0 utp 111 

CSPEL Modeled Emitted Group C cma>ents Deposition Number 

SO2 1 1 I !GAS) O Lser Uef~nec I- XCO-dance i1~1th 

SO4 1 1 2 (Psrtlcle;~ O VISTAS guidance far ESLz 

NQX 1 1 1 a(-~o, , 2 -7) 0 

HVO3 I O 1 :(3AS:1 O 

NO3 1 C 2 iP3Tf1cle! 3 

S3A 1 1 2 ~F'art~cle:~ 3 

PMF I 1 2 (Part~cle] 3 

PtK 1 1 2 ~;,Part~cle) 3 

EC 1 1 2 (Part~cle) 13 

- - - -- - - - 

CALPUFF Model Input Group 4: Map PI-njectiou and Grid Control Parameters. 

Parameter I 

PMAP 

FEAST 

FNORTH 

l UTMZN 

UTVHEPVI 

RikTO 

RLONO 

XLAY 1 

- 

XL.4T2 

D ATL! Pvl 

NX 

YORIGI(:S~ 

l5COMP 

JSCOMP 

IECOMP 

JECOFvlP 

LSAMP 

ISSAtvIP 

J3SAPvIP 

IESAMP 

J ESAMP 

IKESHDN 

Lornmenfs 

Map tJrojectior? Lsed 

User Defimd 

User Defi~ied 

User Defined 

C1~er Defined 

User Defir,ed 

User Defined 

Use; Defired 

Ilse- Defir~ed 

Etsput Usedl Default 

-1214 00'3 

2 5 

1 4;

153 

22 3 

- 

.. 

i 

I 

LCC 

9 

3 

9 

Y 

LO N 

571,:~ 

33 N 

L.5 N 

NWS-83 

238 

UT'd 

O 

0 

- 

I I 

Usei Defined 

User Defined 

User Defiried 

Use- Defired 

User Defined 

Ssmpl ng yid a not ~,sed 

Ssmplng CJ-id is not ~sed 

Sarnpl ng g;rd a not ~sed - -- 

Sam~! r,r~ 3-:j :> ~SEA 

Ssinpl ng yd 1s not ~sed 

I 
I CALPUFF Model Input Gtotlp 5: [Ilutpi~t Options I 

Parameters 1 Input Used 1 Default I Lornments 

I I 'I I 

IWPKI 

ICFRQ 1 

IDFRQ I 

IWFRQ 1 

l PRTU 3 1 Used n$m3 and uy!n-2:s 

IPFDEB I C:e!xg o~tp~rt optiot-s 

NPFDEB 10 I Celxg output optiors 

NN I 1 Q I Cel:.ug o~tput options 

NN? lil ' 1-1 Le!xa outujut oot~ors 

CALPUFF Model Input Group 7: Dry C)eposition Par-ameters for Gases. I 

CALPUFF Input GI-otrp 6: Sub-Grid Scale Cornptex Tel rain Inputs. 

Parameters I fnput Used 

Species 

Default r 

NHlLL 

NCTREC 

MHILL 

XHILL2M 

ZH ILL2M 

XCTDMKM 

VCTDMKM 

Lornlnems 

Not set ~n lLnt!461M Phase 2 tieport 

Not set ~n IW43M Phzse 2 Fieport 

Not set. 111 llfldP.3M Phase 2 Fi~port 

Not set ~n IWA3M Phase 2 Report 

Not set ~n IWAZVl Phase 2 Fieport 

Not set ~n li04!A3M Phase 2 Fieport 

Not set ~n I'I(\:P.3M Phase 2 Report 

0 

$9 

2 

0 

0 

C.OOE+03 

C.OClE+03 

Input Used 

O 15C9 

!OD3 

Default 

~J.'535 

1 '3 00 

Lornments 
I CALPUFF Model Input Group 8: Dly Deposition Paralmete~s fc~r Partikles. I 7 - 

Species Input Used Default C01n111ents 

Size Stcl Dev 

SO4 0 18 L. 3 All P'vl species sxcept PNC s,we 

NO3 0 46 L. 3 

I CALPUFF Model: Input Grwi~p 9: Miscellaneous Di y Depostion Prt~an~ete~s 

I CALPUFF Moclet Input GI-oap 10: Wet Deposition Palorneters. I 

REACTR 

N INT 

IVEG 

species Input Used Default I Comments 

I I 1 I I 

9 

9 

L 

I CALPUFF Model Input Gioup 11: Chemist~y Pororneters, I 

.:, 

3 

1 

S32 

S34 

HN03 

NO3 

PMF 

P MC 

S3A 

EC 

3 O@E-05 

1 CUE-04 

EOOE-05 

1 00E-04 

1 CUE-04 

1 COE-04 

1 COE-04 

1 CUE-OJ 

C U0E+153 

3 OCE-O5 

OCOE+OO 

3 0CE-135 

3 3CE~35 

3 '3CE-35 

3 30E-35 

3 0CE-05 

3 00E-Cl5 

1 O3E-84 

6C10E-05 

1 C4E-04 

100E-I:4 

I 00E-03 

1 DOE-04 

1 DOE-OJ 

O 013E+OC 

3.OClE-C5 

OCI.~E+;~U 

3.CDE-03 

3.CClE-05 

3 00E-05 

3.ODE-C5 

3.OClE-05 I 
Cf 2- O C f. 2 b i, 2 E, :?e ea-l~e- ~ers ans oi CPLZUFF 

PO? UOlf. 
I CALPUFF Mcrdel Input GI-oup 13: Point Source Parameters. I 

CALPUFF Model Input Group 14: Alee soulce Parameters. 

Parameter 

NPTI 

l PTU 

NSPTl 

N PT2 

SRCNAM 

X 

CALPUFF Mode[ Input G~-oup 15: Line Soi~rce Paramete~s. 

Input Used 

2 

10 

O 

' Para~iieter input Used Default Comments 

NAR I 

IARU 

NSAR B 

NAR2 

Default 

1 

c? 

U 

Parameter 

NLN2 

NLIYES 

liNU 

NSLNI 

MXNSEG 

NLRISE 

X L 

H3L 

'24R L 

i.41 b1L 

D XL 

FPRIMEL 

I CALPLIFF Moclel Input Gro~~lr 17: Discrete Receptor Information I 

tommerits 

Use- defined. set to nurr:becof stacks 

LIS~C when sexon31 and nc?c seasnna errlsslor rates are 

cons~dered 

See Tsble L- I oi the BART hlodellt~y Repo? '~r sxrces~fc~frc caran-etels and em1s1011 rates 

9 

0 

3 

- - - 

CALPUFF Model fnput G~oi~p 16: Volume Source Parnniete~s. 

Parameter 1 Enput Usedl Default I t:ornmeiirs < * L. JJser Llefinecf 1Use- Uetlred 

lnpt~t Used 

O 

'J 

9 

7 

5 

0 

0 

O 

'3 

.3 

O 

Paranieter 

NVL '; 

IVLU 

NSVL l 

NVI 7 

t 

0 

Nat used 

Nat ~sed 

Not used 

Not used 

Default 

1 

0 

7 

6 

Input used 

3 

13 

11 

Lomrnents 

Ncat lised 

Not csed 

Not ~sed 

Not ~sed 

Not ~sed 

Not cised 

Not lased 

Not ~sed 

Not csecl 

Not ~sed 

Nut ~sed 

Not ~sed 

Default 

1 

0 

Lornments 

Not LSE~ 

Nnt used 

Not ~sed 

Not used 
POSTUTIL Input Variables 

I POSTUTkL Processor hywt GI oup 1: General Rrin Control Poramete~s I 

L 

IS- I 

ISHR I Llser de'md 

NPER 57 613 Usel- de'lned 

NSPECIhP 9 User deemed 

NSPECOUT 9 

Parameters Input Used Defadt Lo~nments L 

NFILES '1 1 

METFM Z 0 2-0 f'es ultl? e~ther Eh, Temp or F!P~ow1r~ each 

NMET I 12 I%ult~ple 111put met files far t rre pe-IOC 

LCFILES F T F~Iwsmes no: set tg Imver case 

ISYR Llsfr de'tned 

NSCALEC 0 0 

For ammoma .'rvtrtq cwnputes tbe pa-titlon for the TOTAI POSTUTIL Processor tnprrt Gnoup 2: Species Processing Itiformatictn 

FAN ITRATE 

NH3TYP 

BCKNH3 

1 - , 

1 Y.3 5 

ASPECO 

ASPECO 

ASPECO 

ASPECO 

SC! A 

P kt F 

P fvlC 

E C 

0 

-99 

concentrst~on f~elds (204 h33 and HY03) 

lJse monthly a3;e-age Sackg1-ound ammanla 

Fxkc.-aunc hH7 set tu Cl 5 in sccw~dance -:;ith 'ViS-AS 

311 dwce 
CALPOST Input Variables 

I CALPOST P~ocessoi Input GI *up 1: Gener-al Run Control Parimeters 

Co~nrnen ts 

hut-nbe~ of periods tc (;-ocess 

Procesz specles for sll: 1t.y 

6 

L3ACK 

MSOURCE 

LG 

Lf) 

LC T 

LDRING 

NDRECP 

l@GRlD 

Oefault 

O 

Paro~netefs 

ISYR 

ISM3 

ISDY 

ISHR 

NHKS 

NREP 

ASPEC 

]LAYER 

A 

Input Used 

200 1 

1 

1 

1 

8750 

1 

?!ISIE 

1 

0 

0 

F 

C 

F 

T 

F 

F 

50c1' : 

-1 

O 

F 

3 

F 

F 

F 

F 

-1 

- 1 

Ulscrete receptors pro? dec on the whte 

Fil #k~+'+,bV2 !I3 f~i: C fi l3.y _SO b/ Ll SeC 
I CALPOST Plocessol Input Glotl~r 2: Species Pmcessing Information 

Palometer Itil~ut Used Default Comments 

MFRH 7 2 EPP [2833'1 f(RP :I tab~113t10t~ 2s spe~~fiecl Sj, 'b':STA 3 

GHMAX '2 Y 5 Fa 

EEPMC 9 5 0 6 

EEPMF 1 

EEPMCSK i16 0 ,:7 

EES04 3 3 

EEN03 3 3 

EEOC 4 3 

C 

6KSC)IL 12^1'1 4C 13 5 

BKEC 12*0 0 O 02 

BEXTRAY 1 0 10 
I CALPOST Psocessot Input Group 3: Output Options I 

Palarteter I Input Used 1 Default I Co~mments 

I C I C I 1 

LRUNL 

hi;% 

LTSC 

LT3PN 

NT9 P 

ITOP 

LEXCD 

F 

C 

F 

F 

1 

THREW i 

THRESE3 

TERESH2d 

THRESHN 

MD AY 

KCQUNT 

LECHO 

LTlhlE 

LPEAK 

1ECFO 

LPLT 

LGRD 

MDVlS 

LOEBUG 

LVEXTkR 

1 

F 

T 

0 

T 

F 

4 

1 03E+01 

- 1 

-1 

-1 

0 

I 

F 

F 

F 

3&5"13 

F 

F 

C 

F 

F 

r\c3t rreport117g RL~--etigtli avelsges 

Tap 50 table far each averqlng t~me rot se ected 

R~~tiiber of 7x1 vz'ues 31 each recentor selectec 

1,2 3,4 

F 

Spec f~c rxk ~f Top ;a'~es reported 

Identifq. the tliresholc 'cr 1 hcsclr aberag t33 t n-e b$ asslgr,tn 

- 1 

- 1 

- 1 

- 1 

3 

F 

,= 

F 

36EA0 E 

7 - 

12 

- 

,.. 

F 

z nor,-negat~~e .slue 
General Quality Assurance Procedures 

Chapter 6 of the Final VISTAS Modeling Protocol discusses Quality Assurance (QA). The purpose of the QA 

program is to establish procedures for ensuring that products produced by the application of the modeling 

techniques for BART studies satisfy the regulatory objectives of the BART program. 

The air quality modeling staff at Southern Company Services is managing andlor conducting the BART 

Exemption Modeling application for this plant owned by Alabama Power Company. They made sure that all 

recommended methods specified in the Final VISTAS Modeling Protocol were followed and that the modeling 

was carefully and professionally conducted. Initially, the Company retained the services of ENSRIAECOM to 

supplement the training received as part of VISTAS training courses. Additionally, ENSRIAECOM experts 

were given source data for one of Southern Company's BART eligible sources, and they performed a 

complete analysis following the VISTAS common protocol. During this process, the lead Southern Company 

modelers were taught each technical step. 

ENSRIAECOM was used as a third-party review for the CALPUFF analyses. ENSR has conducted numerous 

CALPUFF analyses, and uses CALDESK animation software as well as Lakes Environmental CALVIEW 

software with base maps to visualize the sources, receptors, and meteorology. ENSRIAECOM also uses the 

CALPUFF QA output files in conjunction with ArcMap GIs software to plot the locations of the sources and 

receptors as CALPUFF interprets them from the input data. The output files from CALPUFF and CALPOST 

are typically reviewed independently by ENSRtAECOM staff to assure accuracy and compliance with 

approved regulatory procedures. 

For the exemption modeling, Southern Company's BART modelers made sure that all checks were made 

manuallylvisually as well as by using UltaEdit-32, a file comparing software. Additionally, these datasets were 

randomly checked by another Southern Company modeler. During the modeling process, periodic progress 

meetings were conducted with the project management team members, and phone calls and e-mail 

exchanges were made with the CALPUFF modeling experts at ENSRIAECOM to resolve issues as they 

arose. 

The VISTAS Modeling Protocol states, "To the extent that modeling applications are using pre-defined 

CALMET files and CALPUFF templates, the quality assurance will be straightforward. More detailed steps are 

needed for the setup of modeling files for source-specific applications of subregional domains finer than 4 

km." For this application, the 4-km grid-spaced CALMET files for sub-domain 4 developed by VISTAS and the 

CALPUFF templates were used. Southern Company BART modelers used the test met file to "benchmark" 

the use of the CALMET files on their computers as indicated on page 59 of the VISTAS common protocol. For 

this BART exemption modeling application, documents were developed and will be submitted that contained 

source data required by the CALPUFF modeling system (CALPUFF, CALPOST and POSTUTIL). 
CEMEX 

Demopolis Plant 

Best Available Retrofit Technology Applicability Analysis 

August 2006 

trinityconsultants. corn 
BP A~oco CHEMICAL COMPANY 

Decatur Works 

Best Available Retrofit Technology Applicability Analysis 

January 2007 

trinityconsultants. corn 

r.. - * - 
January 3 1,2007 

1401 Finley Island Road 

Post Office Box 2215 

Decatur. AL 35609 

Ms. Adrienne Newton 

Alabama Department of Environmental Management 

Air Division 

1400 Coliseum Blvd. 

Montgomery, Alabama 36 1 10-2059 

RE: Best Available Retrofit Technology Applicability Analysis 

BP Anzoco Chemical Company - Decatur, Alabama 

Dear Ms. Newton: 

Please find enclosed four (4) copies of a Best Available Retrofit Technology Applicability 

Analysis prepared by Trinity Consultants (Trinity) on behalf of BP Amoco Chemical Company's 

facility located in Decatur, Alabama. This report is submitted for review by the Alabama 

Department of Environmental Management (ADEM) and other stakeholders in the BART 

implementation process. The additional copies of this report are provided for your transmittal to 

U.S. EPA Region 4, the U.S. Forest Service, which is the Federal Land Manager for the Sipsey, 

Cohutta, and Joyce Kilmer/Slickrock Wilderness areas, and the National Park Service, which is 

the Federal Land Manager for the Mammoth Cave and Great Smoky Mountains National Parks. 

The enclosed report describes the BART eligibility of the Decatur Works, BART emissions 

inventory, and air quality analysis methodology and results. A DVD enclosed with the report 

provides electronic copies of air quality model input and output files used to conduct the analysis. 

The Decatur Works is considered eligible for regulation under the Best Available Retrofit 

Technology (BART) provisions of the Regional Haze Rule because certain sources are operated 

within the chemicals (including petrochemicals) manufacturing source category, were built or 

reconstructed between August 7, 1962 and August 7, 1977, and collectively have the potential to 

emit more than 250 tons per year of sulfur dioxide, oxides of nitrogen, and particulate matter, 

which are considered visibility-affecting pollutants. 

The enclosed report documents our determination that the Decatur Works is not subject to BART 

because the BART-eligible operations do not contribute to visibility impairment at any Class I 

areas, as estimated using current modeling techniques and data resources prescribed by ADEM, 

VISTAS, and U.S. EPA. The modeling analyses were prepared in a manner consistent with the 

most recent version of the VISTAS BART Modeling Protocol, updated postprocessing techniques 

for implementing the revised IMPROVE light extinction algorithm, and comments received fiom 

ADEM on BP's source-specific BART modeling protocol. 
Ms. Adrienne Newton - Page 2 

January 3 1,2007 

Trinity and BP appreciate your timely review of the enclosed BART Applicability Analysis for 

the Decatur Works and your continued cooperation in working with BART-eligible sources 

throughout the BART evaluation process. If you have any questions or comments about the 

information presented in the enclosed report, please do not hesitate to call Mr. Ryan Gesser of 

Trinity at (404) 256-1919 or Ms. Karla Shinkunas at (256) 340-5677. 

Sincerely, 

BP DECATUR WORKS 

Dave Harness 

Decatur Works General Manager 

Enclosures 

cc: Ms. Leigh Bacon, ADEM (Montgomery) 

Mr. Ryan Gesser, Trinity Consultants (Atlanta) 
TRMITY CONSULTANTS 

1 100 Johnson Ferry Road 

Suite 685 

Atlanta, Georgia 30342 

(404) 256-1919 

and 

BP A~oco CHEMICAL COMPANY 

DECATUR WORKS 

Finley Island Road 

Decatur, AL 35609 

(256) 340-5677 

January 2007 

Project 061101.0017 
INTRODUCTION ........................................................................................................ 1 

OVERVIEW OF REGIONAL HAZE RULE AND BART REQUIREMENTS ......................... 2 

1.1.1 DETERMINATION OF BART-ELIGIBILITY ......................................................... - 7 

1.1.2 ASSESSMENT OF CONTRIBUTION TOVISIBILITY LMPAIRMENT AND BART 

APPLICABILITY ................................................................................................ 7 - 

1.1.3 POTENTIALLY AFFECTED CLASS I AREAS ....................................................... 5 

1.1.4 CALPUFF MODELING ANALYSES .................................................................. 7 

ORGANIZATION OF BART APPLICABILITY ANALYSIS REPORT ................................. 8 

BART-ELIGIBLE SOURCE DESCRIPTION ............................................................... 9 

BART-ELIGIBLE EMISSION UNITS ............................................................................ 9 

BART-ELIGIBLE SOURCE MODELING EMISSIONS INVENTORY ................................ 11 

2.2.1 FUEL OIL-FIRED BOILER PARTICULATE SPECIATION .................................... 16 

2.2.2 NATCRAL GAS-FIRED CO~~BUSTION UKITS .................................................. 18 

2.2.3 MISCELLANEOUS PROCESS VENTS AND MATERIAL HANDL~NG SOURCES ... 20 

MODELED STACK PARAMETERS AND EMISSIONS .................................................... 22 

AIR QUALITY MODELING ANALYSES ................................................................... 26 

AIR QUALITY MODELING SYSTEM .......................................................................... 26 

SCREENING AND REFINED ANALYSIS TECHNIQUES ................................................. 26 

3.2.1 VISIBILITY ASSESSMENT METRIC ................................................................ 27 

3.2.2 METEOROLOGICAL AND COMPUTATIONAL GRIDS ........................................ 27 

3.2.3 MODEL PROCESSING AND POSTPROCESSING METHODS ................................ 28 

CALMET METEOROLOGICAL PROCESSING ............................................................ 28 

3.3.1 CALMET METEOROLOGICAL DOMAINS ....................................................... 29 

3.3.2 MM5 SIMULATIONS ....................................................................................... 30 

3.3.3 GEOPHYSICAL DATA ...................................................................................... 30 

3.3.4 12-K~I SCREENING ANALYSIS CALMET PROCESSING ................................. 31 

3.3.5 4-KM REF~ED GRID CALMET PROCESSING ................................................ 31 

3.3.6 QUALITY ASSURANCE OF CALMET ANALYSES ........................................... 32 

CALPUFF MODEL PROCESSING ............................................................................. 33 

3.4.1 MODELED EMISSIONS AND CHEMICAL TRANSFORMATIONS ......................... 33 

3.4.2 CALPUFF DISPERSION ALGORITHMS ........................................................... 37 

3.4.3 BUILDING DOWNWASH ................................................................................. 37 

3.4.4 CALPUFF MODELING DOMAINS AND CLASS 1 AREA REcEPTo~~.~.~~~~

3.4.5 BACKGROUND OZONE AND AMMONIA CONCENTUTIONS , ................... '3 

436 '9 ' .%; 

3.4.6 PUFF REPRESENTATION ..................................................... Q ......................... 459 

% %'\ 3.4.7 QUALITY ASSURANCE OF CALPUFF ANALYSES ............ ........................... 45~ . % 3 

2 '4 

. 0. 9" . '4 T. 

,.5 

L ..i, \ 

BP Decatur Works i Trinity Ed&8tants 

BART Applicability Analysis 
CALPOST Pos~~~oc~ssr~~ AND NATURAL BACKGROUND CONDIT~ONS FOR 

LIGHT EXTINCTION AND HAZE INDEX CALCULATIONS ........................................... 45 

3.5.1 POSTUTIL PROCESSING ............................................................................... 45 

3.5.2 CLASS I AREA-SPECIFIC NATURAL BACKGROUND CONDITIONS .................. 46 

3.5.3 VISIBILITY IMPACT CALCULATION ................................................................ 49 

3.5.4 QUALITY ASSURANCE OF POSTPROCESS~\JG ANALYSES ............................... 50 

SCREENING ANALYSIS RESULTS ........................................................................... 51 

SCREENING ANALYSIS IMPACTS AT SIPSEY ............................................................ -51 

SCREENING ANALYSIS IMPACTS AT COHUTTA ........................................................ 52 

SCREENING ANALYSIS IMPACTS AT MAMMOTH CAVE ............................................ 52 

SCREENING ANALYSIS IMPACTS AT JOYCE KILMERISLICKROCK ............................ 53 

SCREENING ANALYSIS IMPACTS AT GREAT SMOKY MOUNTAINS ........................... 54 

SUMMARY OF SCREENING ANALYSES ..................................................................... 54 

APPENDIX A Sample CALPUFF/POSTUTIL/CALPOST Input Files 

APPENDIX B Comparative Analysis for Explicit CALPUFF Modeling 

APPENDIX C Electronic Media File Index 

BP Decatur Works 

BART Applicability Analysis 

. . 

11 Trinity Consultants 

BP Amoco Chemical Company (BP) operates a petrochemical manufacturing plant in Decatur, 

Alabama. The Decatur Works is a major source of air enlissions and operates under a Part 70 

(Title V) major source operating permit (Air Facility ID No. 7 12-0002) issued by the Alabama 

Department of Environmental Management (ADEM). The facility is considered eligible to be 

regulated under the Best Available Retrofit Technology (BART) provisions of the Regional Haze 

Rule. This BART Applicability Analysis Report summarizes BP's determination that the Decatur 

Works should not be subject to BART because the air quality modeling analyses described in this 

report demonstrate that the facility does not contribute to visibility impairment at any federally 

protected Class I areas. 

BP submitted an initial source-specific BART Applicability Modeling Protocol on March 3 1,2006, 

and subsequently received comments from ADEM on July 3 1,2006. BP reviewed these comments 

and provided a response to ADEM on August 25,2006, to clarify certain aspects of the BARTeligible source inventory and applicability modeling analyses as described in this report. In addition 

to these comments on the source-specific modeling protocol for the Decatur Works, BP's evaluation 

of BART-eligibility and the modeling methods used to determine applicability of BART as described 

in this report are consistent with the following guidance documents: 

U.S. EPA, "Regional Haze Regulations and Guideline for Best Available Retrofit 

Technology (BART) Determinations," Federal Register Volume 70, Number 128, 

July 6,2005. 

U.S. EPA, Guidance for Trachcng Progress under the Regional Haze Rule 

(EPA-454B-03-004), September 2003. 

U.S. EPA, Guidance fur- Esiimatirig Natur-a1 Visibility Condifiorzs under fhe Regional Haze 

Rule (EPA-454B-03-005), October 2003. 

U. S . EPA, Interagency Workgroup on Air Quality Modeling (ITFA QM) Phase 2 Sul7z11zar y 

Report (EPA454lR-98-0 19), December 1998. 

U.S. EPA, Guideline 012 Air Qualio, Models, 40 CFR Part 5 1, Appendix W (Revised, 

November 9,2005). 

VISTAS, Protocol for the Application of the CALPUFF Model for Analjses of Best Available 

Retrofit Technology (BART), Revision 3.2, August 3 1,2006. 

VISTAS and U.S. EPA, "Q&A for Source by Source BART Rule" (Draft), October 28,2005. 

ADEM, electronic communication to BART-eligible sources, multiple dates. 

The VISTAS BARTModeling Protocol as revised on August 3 1,2006, is incorporated by reference for 

BP' s source-specific modeling analyses. The VISTAS BART h4odeling Protocol and related 

information (generally made available at the VISTAS BART website') established common technical 

http://vistas-sesarm.org/BART/index.asp 

BP Decatur Works 1 Trinity Consultants 

BART Applicability Analysis 
approaches for quantifying emissions from BART-eligible emission units and conducting screening 

and refined modeling analyses using the CALPUFF modeling system and common data resources. 

BP's analyses generally adhere to the recommendations made in the VISTAS BART Adodeling 

Protocol as described in this report and adapted per ADEM guidance to the source-specific analysis 

of visibility impacts attributable to the Decatur Works. 

1. OVERVIEW OF REGIONAL HAZE RULE AND BART REQUIREMENTS 

The Regional Haze Rule requires that major sources of visibility-affecting pollutants belonging to one 

or more of 26 specific industrial source categories evaluate BART if the source was "in existence" 

(i.e., built or reconstructed) before August 7, 1977 and began operation after August 7, 1962. Such 

sources are termed "BART-eligible sources." Major sources of visibility-affecting pollutants have the 

potential to emit 250 tons per year (tpy) of one or more of oxides of nitrogen (NOx), sulfur dioxide 

(SO?), and particulate matter less than 10 micrometers in aerodynamic diameter (PMlo). Hereafter, 

the "BART-eligible source" is taken to mean the collection of sources at a facility in existence during 

the relevant time period within one or more BART source categories that has potential emissions of 

one or more visibility-affecting pollutants in excess of 250 tpy. The BART-eligible source may 

include multiple emission units, but need not include the entire facility. 

The U.S. EPA BART guidelines define the following three steps for determining which 

sources at a facility are BART-eligible: 

1. Identify the emission units in the BART source categories. 

2. Identify the start-up dates of those units. 

3. Compare potential emissions to the 250 tpy cutoff. 

Chemical plants (including petrochenlicals) are one of the listed source categories, and 

include process units and support facilities that are considered to be part of major Standard 

Industrial Classification 28 - Chemicals and Allied Products. BP's Decatur Works has 

determined that 46 emission units comprise the BART-eligble source because the units 

operate at a chemical manufacturing plant, were in existence on August 7, 1977, and began 

operation after August 7, 1962. This collection of emission units has potential emissions 

greater than 250 tpy of NOx, SO?, and PM,,, and accordingly was evaluated to determine 

whether the facility is considered exempt from BART. Specific information about these 

emission units is provided in Section 2 of this BART Applicability Analysis Report. 

1.1.2 ASSESSMENT OF CONTRIBUTION TOVISIBILITY IMPMRMENT AND 

BART APPLICABILITY 

In its role as technical analysis coordinator, VISTAS developed a common modeling 

protocol and data resources for use by state regulatory agencies and BART-eligible 

sources. The final VISTAS BARTModeliizg Protocol was issued on December 22,2005, 

was revised most recently on August 3 1,2006, and prescribes modeling techniques and 

BP Decatur Works 

BART Applicability Analysis 

2 Trinity Consultants 
data resources to conduct screening and refined analyses to assess whether a BARTeligible source is subject to BART. 

A BART-eligible source is determined to be subject to BART if the source causes or 

contributes to visibility impairment at a federally protected Class I area. Causation is 

defined as a single-source impact of I .O deciviews (dv) or more and contribution is defined 

as a single-source impact of 0.5 dv or more, each evaluated on a 24-hour average basis. 

The deciview is a metric used to represent normalized light extinction attributable to 

visibility-affecting pollutants. To determine whether a BART-eligible facility causes or 

contributes to visibility impairment, U.S. EPA guidance requires the use of an air quality 

model, specifically reconmending the CALPUFF modeling system, to quantify the 

impacts attributable to a single BART-eligible source. Because contribution to visibility 

impairment is sufficient cause to require a BART determination, 0.5 dv is the critical 

threshold for assessment of BART applicability. 

Regional haze is quantified using the light extinction coefficient (b,,), which is expressed 

in terms of the haze index expressed in dv. The haze index (HI) is calculated as shown in 

the following equation. 

The impact of a BART-eligible source is determined by comparing the HI attributable to a 

source relative to estimated natural background conditions. The background extinction 

coefficient be,. backmu"* is affected by various chemical species and the Rayleigh scattering 

phenomenon and has previously been calculated as shown in the following equation. 

where, 

bso4 =~[(NH~)~so~~~(RH) denotes the ammonium sulfate concentration 

b,, =3[h7H4~0,If(Jw [NH,NO, ]denotes the ammonium nitrate concentration 

b,, = ~[oc] [oC]denotes the concentration of organic carbon 

b,,, = ~[soil] [soil] denotes the concentration of fine soils 

b,, = 0.6[~oarse ass] [coarse Mass]denotes the concentration of coarse dusts 

b, = 1 O[EC] [EC] denotes the concentration of elemental carbon 

b,,, = ~~~l~i~h scattering 0 Mm-' by default) Rayleigh Scattering is scattering due to air molecules 

f (RH ) = Relative Humidity Function 

[ ]=Concentration in pg/m3 

More recently, the Interagency Monitoring of Protected Visual Environments (IMPROVE) 

workgroup has proposed a more robust equation for calculating background visibility, as 

described in detail in a report entitled "Revised MROVE Algorithm for Estimating Light 

Extinction from Particle Speciation ~ata."' The updated algorithm, which has been 

BP Decatur Works 

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3 Trinity Consultants 
approved by the IMPROVE Steering Committee and is currently undergoing peer review, 

provides a more refined calculation by including visibility impairment due to the following 

processes: 

A Visibility impairment due to different sizes of sulfates, nitrates, and organic carbon 

A Visibility impairment due to sea salt particles 

A Distinct water growth curves (i.e.,ARH)) for small sulfates and nitrates, large 

sulfates and nitrates, and sea salt 

A Elevation-dependent (hence Class I area dependent) Rayleigh scattering coefficient 

A Visibility impairment due to gaseous nitrogen dioxide (NO?) 

The revised IMPROVE light extinction algorithm takes the following forrn: 

For the purposes of calculating current, future, and natural background visibility at Class I 

areas as part of its reasonable progress analyses, VISTAS intends to present regional air 

quality modeling results using both the default and the newly revised IMPROVE light 

extinction formula. Values for the parameters listed above specific to the natural 

background conditions at the Class I areas considered in this analysis are provided on an 

annual average basis in the U.S. EPA's Guidance for Estimating Natuml Visibility 

Conditions under the Regional Haze ~ule.~ More detailed information about the natural 

background conditions particular to Class I areas potentially affected by BP's Decatur 

Works and implementation of the revised IMPROVE equation are provided in Section 3.5 

of this report. 

Particulate species that affect visibility are emitted from anthropogenic sources and include 

coarse particulate matter (PMC), fine particulate matter (PMF), and elemental carbon (EC), 

as well as precursors to secondary organic aerosols (SOA) and fine particulate matter such 

as SO2 and NOx. The extinction coefficient due to emissions of visibility-affecting 

pollutants from a single BART-eligible source be,,, is calculated using an air quality 

model. The extinction due to the BART-eligible source is calculated as shown in the 

following equation. 

U.S. EPA, Guidance for Estiniatiilg Natuld Visiblllp Corlditio~zs Under the Regional Haze Rule. Table 2-1, 

Attachment A, September 2003, EPA-454lB-03-005. 

BP Decatur Works 

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40, = 3[@% SO, lf (m 

bN03 = 3[m4N031f(m) 

b, = ~[SOA] 

bPMF = 1[pMd 

b,, = O.~[PMC] 

b,, = 1 O[EC] 

bN, = 0.33[~0,] 

f (RH) = Relative Humidity Function 

[ ] = Concentration in pg/rn3 

[(NH, )z~~,] denotes the ammonium sulfate concentration 

[NH~NO, ] denotes the ammonium nitrate concentration 

[sO~]denotes the concentration of secondary organic aerosols 

[~MF]denotes the concentration of fine PM 

[PMC] denotes the concentration of coarse PM 

[EC] denotes the concentration of elemental carbon 

[NO,] denotes the concentration of nitrogen dioxide 

BP used screening and refined modeling techniques as described in the VISTAS BART 

Modeling Protocol to detennine whether BART-eligible operations at the Decatur Works 

contribute to visibility impairment at any Class I areas. The VISTAS BARTModelilig 

Protocol specifies that all Class I areas within 300 km of a BART-eligible source must be 

evaluated to determine whether the source contributes to visibility impairment. Table 1-1 

summarizes the distances separating BP's Decatur Works from all Class I areas within the 

VISTAS region and adjacent states. Consistent with the VISTAS BARTModeling Protocol, 

only those Class I areas within 300 km were considered further in the BART applicability 

modeling analysis. 

BP's DECATUR WORKS 

Class I Area Distance (km) 

Breton (LAIMS) 

Cape Romain (SC) 

Chassahowitzka (FL) 

Cohutta (GA) 

Dolly Sods (WV) 

Everglades (FL) 

Great Smohy Mountains (NCITN) 

Hercules Glade (AR) 

James River Face (VA) 

Joyce Kilmer/Slickrock (NC) 

Linville Gorge (NC) 

Mammoth Cave (KY) 

Mingo (h40) 

Okefenokee (GA) 

Otter Creek (WV) 

Shenandoah (VA) 

Shining Rock (NC) 

Sipsey (AL) 

St. Marks (FL) 

Swanquarter (NC) 

Wolf Island (GA) 

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1.2 ORGANIZATION OF BART APPLICABILITY ANALYSIS REPORT 

The remainder of this BART Applicability Analysis Report is organized as follows. 

A Section 2 describes the BART-eligible emission units at the Decatur Works and the emission 

rates modeled in the BART Applicability Analysis. 

A Section 3 describes the procedural and technical guidance for conducting Class I area 

analyses using the CALPUFF modeling system, including the data resources, technical 

modeling options, and quality assurance methods used in the CALMET, CALPUFF, and 

CALPOST analyses. 

A Section 4 describes the results of the screening modeling analyses. 

A Section 5 describes the results of the refined modeling analyses. 

A Section 6 presents a summary of the BART Applicability Analysis and conclusion that the 

Decatur Works is not subject to BART. 

Supplemental information is provided in several appendices to this report. Appendix A contains 

sample model and postprocessing input and output files used for BP's analysis of the Decatur Works. 

Appendix B presents a comparative analysis demonstrating the explicit modeling approach used in 

CALPUFF. Electronic copies of model input and output files are provided on electronic media 

accompanying this BART Applicability Analysis Report, a file index for which is presented in 

'4ppendix C. 

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This section of the BART Applicability Analysis Report describes the emission units that comprise 

the BART-eligible source at BP's Decatur Works. Emissions and exhaust characteristics of each 

emission unit are quantified to demonstrate how each unit was represented in the modeling analysis. 

BP reviewed the criteria for BART-eligibility and determined that the 16 emission units described in 

Table 2-1 comprise the BART-eligible source at the Decatur Works. The table also includes potential 

emissions from each unit. Emissions in bold font indicate changes from the original BP BART 

Applicability Modeling Protocol afier a closer review of emission factors and calculations. 

Emission Unit 

Crystallizer Scrubber Vent 

Feed Slurry Dm 

Dryer Vent Scrubber 

PTA Blos Dust Collector ~ystem' 

T-741 Condensate 

Date Built or 

LP.4 

HP A 

Catox Scrubber 

Caroh Furnace 

Storage Silo Vent Scrubber 

T-761 MAH Tower 

Boiler kAB 4302 

T-741 MA Tower 

Acenc Acid Scrubber 

Catoa Scrubber 

Blower Vent 

HP.4 

LPA 

T-741 M.4 Tower Condensate 

Storage Silo Baghouse 

Crystallizer Scrubber Vent 

Feed Slurry Dm 

Dper \'en1 Scrubber 

Sll05 storage2 

Am Cenmfuge Hold Tank Volt 

EB-I01 Process Heater 

EB-I03 Process Heater 

EB-104 Rocers Heater 

Blower Vent 

Acenc Ac~d Tank Scrubber 

Cator Scrubber 

Dehydrahon Tower Vent 

HP4 

LP.4 

Dchydranon Tower Condcnsatc 

Storage 5110 Baghousc 

0-101 Roces Heater 

h%-102 Process Heater 

h%-401 Process Heater 

Manne Dock Rare 

Kb-I04 7 MMBTUk Rebo~ler 

PX Flare (KM-503) 

Crystallizer Scrubbcr Vent 

Feed Slurry Drum 

Dryer \'en1 Scrubber 

Silos storaae3 

Potential Emissions 

SO2 NOx PM,, VOC 

Total Potential Emissions (tpy) I 981 554 400 3.398 

I Systcm consms of 15 sllos of smilar desp and operation 

2. System constas of I0 silos of similar desp and apciation 

3 System consists of I0 silos of s~milar deslp and opermon 

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Note that the original protocol referred to a list of 49 emission units. Since the time of the initial 

protocol, the U.S. EPA provided additional guidance regarding the "integral-to-the-process" criterion 

for BART eligibility. BP determined that three boilers (Boiler 6301, Boiler 6351a, and Boiler 6351b) 

do not meet the BART eligibility requirements because they are not integral to the chemical 

production process as they only provide steam and do not fall into their own BART eligible source 

category. All three boilers have a maxinlum heat input capacity less than 250 MMBtuIhr. These 

boilers currently have the capability to combust process by-products as an alternative fuel; however, 

combustion of these fuels is not routine. BP submitted a major modification permit application to 

ADEM to make enforceable in the Title V permit that by-product fuels from the chemical process 

will not be fired in these boilers under separate cover on Au~st 16, 2006. Therefore, these units 

were removed from the BART-eligible source inventory described in Table 2-1 and are not 

considered further in this BART Applicability Analysis. 

Revisions to the emissions in Table 2-1 are primarily due to a review of the appropriate AP-42 

emission factors. The change in total potential emissions reflects the cumulative changes of each 

unit, as well as the removal of the three boilers that are not integral to the process. The initial BP 

Applicability Modeling Protocol did not take credit for the Low-NOx burner installed on Boiler 4302. 

The reduced NOx emissions from this unit are associated with the change to the Low-NOx emission 

factor for fuel oil combustion. Similarly, emission factors for the process heaters have been updated 

to reflect Low-NOx burners where appropriate, as well as the correct size category for units less than 

100 MMBtuihr. Table 2-2 presents the AP-42 emission factors that were used to calculate emissions 

for each combustion unit. 

TABLE 2-2. COMBUSTION EMISSION FACTORS 

Source Codel 

Emission Unit Stack ID 

Boiler #AB 4302 BoilerBPD12 

EB-I01 Process Heater 111 PXIBPD27 

EB-I03 Process Heater $1 PXBPDZ8 

Kb-101 Process Heater 112 PXIBPDlO 

Kb-102 Process Heater #2 PXBPD41 

Kb-401 Process Heater #Z PXBPD42 

Beat Input 

nvrrn~) 

281 

100 7 

87 

174 

170.2 

94 3 

Natural Gas Emission Factors 

NOr SO, PM 

(Ib/MMscfl (Ib/MMscf) (IbiMMscf) 

122.4 0.6 7.6 

35 7 0.6 7.6 

35.7 0.6 7.6 

34.1 0.6 7.6 

33.5 0.6 7.6 

100 0.6 7.6 

Fuel Oil Emission Factors 

NOr so2 PM 

Note that the NOx natural gas combustion emission factor for Boiler 4302 is based on a vendor 

guarantee of 0.12 Ib/MMBtu rather than AP-42. BP has conducted source testing to verify this 

guarantee. Similarly, NOx emissions for No. 2 PX Process Heaters Kb-101 and Kb-102 are based on 

compliance test results. The remaining factors are based on AP-42 Chapters 1.3 and 1.4 for fuel oil 

and natural gas combustion, respectively. 

BP's Decatur Works operations are BART-eligible since potential emissions exceed 250 tpy for at 

least one (in fact, each) of NOx, SO2, and PMlO, which are considered visibility-affecting pollutants. 

Note that many of the otherwise BART-eligible emission units have potential emissions only of 

volatile organic compounds (VOC), which VISTAS and ADEM have determined are not visibilityaffecting pollutants for the purposes of BART applicability analyses. Section 4.1.3 of the T/ISTAS 

BP Decatur Works 

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BART Modeliiig Protocol describes the regional modeling analyses showing that cumulative VOC 

emissions do not contribute to visibility impairment within the VISTAS region: 

VOC enzissions fiorn all antlzropogenic point sources in every VISTAS State were 

reduced bj? 100% (i.e., eliminated). The nzaximunz 24-hr inzpact of all VOC 

emissions fioni all point sources tlzrougl7out the VISTAS domain was thus 

determined to be less than 0.5 dv (compared to annual average natural background) 

at eveq? Class I area in the VISTAS domain and in adjacent States. It follo~)s that 

the inzpact of anji one BART-eligible source would be much less than 0.5 dv. Based 

on these analyses, the J/ISTAS States have concluded that J/OC emissions fioin 

BART sources do not cause or contrzbute to visibility inzpairnzent and do not need to 

be included in B.4RT analj~ses. 

As a result of this determination, 19 of the otherwise BART-eligible emission units operated by BP's 

Decatur Works are excluded from further evaluation since these units do not emit visibility-affecting 

pollutants. The remaining 27 emission units are considered the BART-eligible source at BP's 

Decatur Works. These units include one boiler rated at 281 MMBtu/hr, four natural gas-fired process 

units associated with #2 PX, three natural gas-fired process units associated with #1 PX, a catalytic 

oxidation furnace at #3 Oxidation, a flare at the Marine Loading Dock, the PX flare, three goups of 

storage silos, and thirteen other process vents that emit PM only. 

Whereas the BART eligibility determination relies on potential emissions of visibility-affecting 

pollutants, the BART applicability modeling analysis utilizes maximum actual 24-hour average 

emission rates of NOx, SO?, and PMlo. The VISTAS BARTModeling Protocol specifies the following 

hierarchy of information resources to establish the maximum actual 24-hour average emission rate for 

BART applicability modeling over the prior three-to-five year period: 

A 24-hour maximum emissions observed using a Continuous Emission Monitor (CEM) for the 

period 2001 through 2003 

A 24-hour maximum emissions observed using a CEM for any representative period 

A Facility stack test emissions 

A Potential to emit 

A Permit allowable emissions 

A Emissions factors from U.S. EPA AP-42 source profiles 

BP used a combination of representative stack test data, potential emissions based on enforceable 

emissions and operating limits, and AP-42 emission factors to determine the 24-hour average 

maximum actual emission rates of visibility-affecting pollutants. Note that the initial BP Modeling 

Protocol essentially specified potential emissions for each source. Upon further review of actual he1 

throughput data, BP quantified and modeled the maximum 24-hour actual emissions from 

Boiler 4302, which were determined based on the maximum daily fuel throughput over the last five 

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BART Applicability Analysis 

11 Trinity Consultants 
years. Table 2-3 summarizes the emission rates from each BART-eligible emissions unit considered 

in the applicability modeling analysis. 

TABLE 2-3. SLJMMARY OF 24-HOUR AVERAGE MAXIMUM ACTUAL EMISSION RATES 

Emission Unit Source CodelStack ID 

Crystallizer Scmbber Vent 

Feed Slurry Drum 

Dryer \'ent Scrubber 

PTA Silos Dust Collector System 

Catox Furnace 

Storage Silo Vent Scrubber 

Boiler #AB 4302 

Storage Silo Baghouse 

Crystallizer Scrubber Vent 

Feed Sluny Drum 

Dryer Vent Scrubber 

Silos Storage 

Atm Centrifuge Hold Tank Vent 

EB- I0 I Process Heater 

EB-103 Process Heater 

EB-104 Process Heater 

Storage Silo Baghouse 

Kb- 101 Process Heater 

Kb- 102 Process Heater 

Kb-40 1 Process Heater 

Marine Dock Flare 

ICb-104 7 MMBTUihr Reboiler 

PX Flare (KM-503) 

Crystallizer Scrubber X'ent 

Feed Slurry Drum 

Dryer Vent Scrubber 

Silos Storage 

24-Hour Average Maximum Emissions 

SO2 NOx Total PM,o Total PM2, H~SO,' 

(Iblhr) (Iblhr) (lblhr) (lblhr) (lblhr) 

- 

1. For fuel oil combustion, all condensable inorganic particulate matter (PIC) emissions 

gas combustion. the sulfate portion of PIC is estimated based on SO2 emissions with 5% 

are conservatively assumed to be sulfates. For natural 

assumed to be converted to PIC. BP may refine these 

assumptions upon further analyses. 

.4s stated above, emissions from Boiler 4302 represent maximum actual emissions based on 

inaxiinum daily fuel throughput from 200 1 through 2005. These actual en~issions are based on 

natural gas combustion since BP has not burned fuel oil in Boiler 4302 over the last five years. 

Nonetheless, BP presents modeling results in Sections 4 and 5 from both fuel oil combustion and 

natural gas combustion in Boiler 4302 since U.S. EPA's BART "Q & A" guidance indicates "where a 

unit may burn more than one hel.. .the fuel resulting in the highest emission rates should be used for 

the modeling (even if that fuel has not been used in the most recent 3 or 5 year period)." However, 

the natural gas combustion results provide a true indication of BP's visibility impact under normal 

steady-state operations because the facility does not typically burn fuel oil in Boiler 4302. BP 

reviewed daily records of hourly heat input and determined that the maximum 24-hour average heat 

input to Boiler 4302 was 207.4 MMBtuilx, which was used as the basis to compute the maximum 

actual 24-hour average emission rate. 

- -- 

BP Decatur Works 

BART Applicability Analysis 

12 Trinity Consultants 
Table 2-4 presents a comparison of maximum actual fuel oil and natural gas combustion emissions 

for Boiler 4302. 

Table 2-3 includes 24-hour maximum emission rates of primary sulfates (as sulfuric acid mist from 

combustion sources) and distinguishes the emission rates of Total PMlo (TPMlo), which includes 

emissions of TPM2.5. Modeling of visibility impairment requires that the components of the exhaust 

stream be speciated because different types of particulate matter affect visibility to varying extents. 

The amount by which a mass of a certain species scatters or absorbs light is termed the extiiiction 

efzciency or ex-tinction coefjcient, and ranges fi-om values of 0.6 m21g for coarse particulate matter 

to 10 m2ig for elemental carbon. Fine particulate matter (1 m'lg) and organic aerosols (4 dig) scatter 

light with intermediate efficiencies, and ammonium sulfate and ammonium nitrate (that forms from 

precursor SO-, and NO?; emissions in the presence of ambient ammonia) are hygroscopic species that 

are particularly efficient light scatters in the presence of ambient water vapor (3fRH) m21g, where 

ARH) is a function of the relative humidity). The size distribution of particle species is also 

important, since smaller particles may be transported longer distances than larger particles and 

dispersed differently under prevailing ambient conditions. Figure 2-1 depicts the speciation of 

visibility-affecting pollutant emissions as represented in the VISTAS BARTModeling Profocol. 

Emission Unit 

Boiler #AB 4302 

FIGURE 2-1. PARTICULATE ~~~TTER SPECIATION 

(-4FTER FIGURE 4-3 OF THE I/ISTAS BART MODELING PROTOCOL) 

BP Decatur Works 

BART Applicability Analysis 

Daily Maximum Fuel Use 

Natural Gas Fuel Oil 

(MMBtuhr) (MMBtuihr) 

207.4 207.4 

13 Trinity Consultants 

Max 24-hr Natural Gas Emissions 

NOx so2 PM 

(1bh.r) (Ibihr) (Ibm 

24.89 0.12 1.55 

Max 24-hr Fuel Oil Emissions 

NOr so2 PM 

(IbW (Ibw (Ibihr) 

55.31 164.98 14.18 
The FLM have published speciation guidance for certain source types (e.g., gas-, oil-, and coal-fired 

con~bustion sources). BP utilized the default speciation profile compiled by VISTAS for the fuel oilfired boiler. This boiler was classified as uncontrolled, industrial residual oil boiler burning No. 6 

Fuel Oil with a sulfur content of 0.76%. Note that the particle size speciation in the default speciation 

profile compiled by VISTAS was updated to reflect the most recent version of AP-4L4 Similarly, BP 

used AP-42 speciation profiles for the natural gas combustion units. For the Boiler 4302 natural gas 

combustion scenario, BP used the natural gas AP-42 speciation profile. BP is not aware of specific 

guidance for the miscellaneous process vents and material handling sources. Default speciation 

profiles compiled by VISTAS did not include specific source types operated at BP's Decatur Works. 

Therefore, BP assumed that the particulate emissions from the scrubbers, bin vents, silos and 

baghouses associated with these miscellaneous process vents and material handling sources were all 

filterable PM emissions, with one exception.' 

While few site-specific data are available to estimate speciated emissions, BP has reviewed what data 

are available to arrive at a conservative, yet reasonable estimate of speciated emissions. However, it 

should be noted that the data quality on PM speciation is inadequate for setting regulatory emission 

hits and are provided here solely as the best estimated data for a scientific analysis of potential 

impacts on visibility impairment at Class I areas using CALPUFF modeling. The following analysis 

does not represent source test results for specific sources at the Decatur Works. 

NOx emissions from the Decatur Works' BART-eligible sources result from combustion operations. 

Similarly, SO2 emissions emanate from combustion sources, and result from the incomplete oxidation 

of fuel-bound sulfur. Primary emissions of sulfuric acid nllsts or vapors, if any, are assumed to occur 

as only a small percentage of the primary SO2 emissions unless an emission factor has otherwise been 

published. Because of the condensable nature of such emissions and the distinct effect on visibility 

caused by sulfates, primary sulfate is evaluated as a distinct, speciated particulate fraction. 

Condensable particulate matter (CPM) emissions, unlike filterable emissions, have not historically 

been measured or regulated for the affected sources. 

PM emissions can be differentiated with respect to size, point of fonation, and composition. 

Table 2-5 gives definitions for the nomenclature used herein. 

U.S. EPA, Conzp~lation ofAir Pollutant Emission Factors, .4P-42, Fzjrh Edition, Volume I: Chapter 1.3, Fuel 

Oil Conzbustion, Table 1.3-5, September 1998. 

AS the Crystallizer Scrubber Vent also emits VOC, it was conservatively assumed that PM emissions from this 

unit were condensable. PM emissions from the Feed Sluny Drums, Dryer Vent Scrubbers, and Hold Tank were also 

assumed to be condensable. 

BP Decatur Works 

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