## 2.0 

## Source description and emissions data

2.1 

### Unit-specific source data The emissions data used to assessthe visibility impacts at the Class Iareas within 300 km of Plant Miller are discussed in this section. ADEM and JCDH have indicatedthat CAlR will satisfy BARTfor EGUsfor SO2and 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-specificemissions and speciation factors and/or defaultvalues 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-combustionNO, or SO2control equipment exists.
Total PMlo is comprisedof 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 combinedwith the highest24 hour heat input value for this periodfrom 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 specifiesfor 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 consistentwith the method used by Alabama Powerto derive these emissions for TRI purposes. This approach assumes that the H2S04 emissions released from the stack are proportional to SOnemissions from combustion and are dependent on the fuel type and the removal of H2S04by 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 SO2emissions. Appendix A providesthe basis for the site-specificvalues 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 SO2emitted. 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, consistentwith the CALPUFF default value for fine particles. The geometric standard deviationfor both fine and coarse particles will be set to 2 microns, consistentwith the CALPUFF defaultvalue. The 0.48 micron diameter value for fine particles comes from the default values in sample inputfiles presentedon the TRC web site. There is no default value presented for the coarse particleson 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 allowsfor 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 2006accurate 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 modelingas well as the BART determination modeling, if needed. Table 2-1 provides a summary of the modeling emission parametersto 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 representthe maximum 24-hour average Ib/hr rates (excludingdays where startup, shutdown, or malfunctions occurred). For NO, and SO2the values are directlyfrom CEMS. Filterable PMlo emissions were calculated using the higheststack test over the 2003 to 2005 period and multiplying these values times the maximum 24-hour average heat input derivedfrom 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 pulverizedcoal unit with an ESP. PMlo speciationwas then performedas 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 periodswith andwithout SCR operation. For these, the maximum 24-hour average rates were extractedfrom the seasonal (May 

## - September) and non-seasonal(October 

### - April) CEMS data.
If the BARTexemption modeling indicates that a BART determination is required, then one or more particulate matter control optionswill be considered for the modeling to determine visibility improvementfrom the baseline case. The BART engineering analysis will providethe justifications for the selected, technically feasible options and the species-specific control efficiencies. Table 2-1 will be updatedto provide the modeling parameters for these feasible options and resubmitted to ADEM andJCDH for review. Any site-specific deviationsfrom the default particulate matter speciation guidancewould be outlined at that time.

082506 Miller BART Modeling Protocol.doc August PO06

### Table 2-1 

### Plant Miller modelingemission 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 H2S043rganic SO2 N"x P"lo soit PM soif EC PM'~ I I I I I I I I I I I I I m 

# I mls 

# I deg K 

# Ilbdhr 

# Ilbdhr 

# I Ibshr Ilbdhr llbslhr Ilbshr llbslhr (ibslhrllbslhr Ilbdhr Ilbshr

August 2006

### Table 2-2 

### (Continued) Plant Miller modeling emission parameters
Notes:

1 With Alabama being a CAlR affected state, SO2and NO, emissions are not BART-applicable for EGU sources assumingADEM and 

### JCDH agree with

EPA's interpretationof the BART final rule. The emissionsfor SO2and NO, are providedfor informationpurposes, 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 molecularweights of H2S04 and SO4 are 98 and 96 respectively; thereforethe conversion factor from H2S04to SO4is 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 databasesfor three years (2001 

### - 2003) (VISTAS common protocol Section4.4.2). The sub-regional modeling domains are strategically designed to cover all potential BART eligible sources within VISTAS states and all PSD Class 

### Iareas within 300 km of those sources (to the nearestedge). The extents of the 4-km sub-regionaldomains are shown in Figure 4-4 of the VISTAS common BART modeling protocol. The BART modeling for Plant Miller will be done usingthe 4-km subdomain 4. USGS 90-meter Digital Elevation Model (DEM) files were used by VISTAS to generate the terrain data at 4-km resolutionfor input to the 4-km sub-regionalCALMET run. Likewise, USGS 90-meter Composite Theme Grid (CTG) files were used by VISTAS to generate the land use data at 4-km resolutionfor 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 Sections4.3.2 and 4.4.2 in the VISTAS common BART modeling protocol for more detail on these issues.
It is intendedthat all of the modeling for Plant Miller will use the 4-km subdomain 4. However, if the results indicatethat the modeling could be improvedwith 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.
Inthe event that a finer grid resolution is used, CALMET must be rerun. Other modifications to inputs of CALMETwould includethe extent of the modelingdomain, the resolutionof 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 needto be changed because of disk space restrictions. The size of the CALMET output is directly proportionalto the grid resolution of the 

### m. The domain would be limited to the source and the exclusive Class I area(s) being assessedwith 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 measurementsof ozone from all non-urban monitors, as generated by VISTAS and availableon the VISTAS CALPUFF page on the EarthTech 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 recommendedby 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 monthlyf(RH) at Class I Areas For each of the applicable Class 

### I areas, natural backgroundconditions must be established in order to determine a change in natural conditions related to a source's emissions. The modeling described by this protocoldocument intends to use annual average natural background light extinction (EPA 2003 values).

082506 Miller BART Modeling Protocol.doc August 2006To determine the input to CALPUFF, it is first necessary to convert the deciviewsto extinction using the equation: Extinction (Mm") 

### = 10exp(deciviews/l0). For example, the EPA guidance document indicatesfor 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 includesthe default 10 Mm-1for Rayleigh scattering. The remainingextinction is due to naturally occurring particles,and should be held constant for the entireyear's simulation. Therefore, the data providedto CALPOST for Great Smoky Mountainswould be the total natural backgroundextinction minus 10 (expressed in Mm-l),or 11.38. This is most easily input as fine soil concentrations (11.38 pg/m3)in CALPOST, since the extinction efficiencyof soil (PM-fine) is 1.0 and there is nof(RH) component. The concentration entries for all other particle constituentswould be set to zero, and the fine soil concentration would be kept the same for each month of the year. The monthlyvalues for f(RH) that CALPOST needs will be taken from "Guidancefor 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 refinedCALPUFF analysis to be conductedfor 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 CALMETVersion 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 includesCALMET, 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 (CALPOSTand 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 

### Iareas within 300 km of the source, plus a 50-km buffer. If there is the needfor a refinedanalysis with a finer grid, a supplement to this modeling protocolwill be provided describingthe proposed procedures. The receptors used for each of the Class Iareas 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 conductedfor Miller Units 1,2, 3 and 4 (BART eligible units)for each Class 

### Iarea 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 modelingfor 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 protocolwill be updatedto 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 buildingdownwash effects are not required to be included unless the state directs the source to includethese effects. Since Plant Miller is more than 50 km from the nearest Class Iarea, buildingdownwash effects will not be included in the CALPUFF modeling.
The POSTUTIL utility program (VISTAS common protocol Section4.4.2) will be usedto repartition HN03and NO3 using VISTAS-provided ammonia concentrations derivedfrom 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 extinctionand haze impact calculations The CALPOST postprocessor will be used as prescribed in the VISTAS protocolfor the calculation of the impactfrom 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) IMPROVEIEPAformula, which is appliedto determine a change in light extinction due to increases in the particulate matter component concentrations. Usingthe 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/m3and 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 Iareas will use CALPOST Method 6 (VISTAS common protocol Section 4.3.2). Each hour's source-causedextinction is calculated byfirst using the hygroscopic components of the source-causedconcentrations, due to ammonium sulfate and nitrate, and monthly Class 

### I area-specific f(RH) values. The contributionto the total source-causedextinction from ammonium sulfate and nitrate is then added to the other, non-hygroscopiccomponents 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 significancethreshold for the contribution to visibility impairment is 0.5 deciviews. The VISTAS protocol (Section 4.3.2) indicatesthat with the use of the 4-km sub-regionalCALMET database, a source does not cause or contribute to visibility impairmentif the 98th percentile (or 8th highest) day's change in extinction from natural conditions does not exceed 0.5 deciviewsfor any of the modeledyears (an added check is: the 22nd highest predictionover 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 protocolfor the analysis to determine whether a source is subject to BART. Again, it should be noted that the modeling for Plant Millerwill focus on Subregional Fine-Scalemodeling 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 modelingfor 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 determinedto 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 manneras described in the VISTAS protocol (Section 4.5). A report will be producedthat 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. Forthe 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 inTable 4-3 of the VISTAS protocol.


### 3. A discussion of the number of Class I areas with visibility impairmentdue to source emissions for the 98th percentile days in each year (andthe 98th percentile over all three years modeled) greater than 0.5 dv.
4. Forthe Class I area with the maximum impact, a discussion of the number of days beyondthose excluded (e.g., the 98th percentile for refined analyses) that the impact of the source exceeds 0.5 dv, the numberof 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, resultsfor those Class 

### Iareas for which impactsof 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 performedfor 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 identifiedin the engineering analysis phase of the BART assessment. The results presented will be a comparison of the 98'h percentilevalue for the baseline and each control strategy derived as is outlined above for the exemption modeling. The same statistics as those mentionedabove 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 modelingwill be submitted on CDROM or DVD media.

082506 Miller BART Modeling Protocol.doc August 2006

## Appendix A Basisfor Source-Specific Sulfuric Acid Emissions for BART Baseline Case

082506 Miller BART Modeling Protocol.doc August 2006

### Appendix A Basisfor Source-Specific Sulfuric Acid Emissions for BART Baseline Case

Sulfuric Acid (H2S04) 

### Emissions Duringthe combustion of sulfur-containing fuels, a percentageof the SO2formed is further oxidized to SO,. As the flue gas cools acrossthe air heater,this SO3combines with flue gas moisture to form vapor-phase andlor condensedsulfuric acid (H2S04). The baseline H2SO4 emissions shown in Table 2-1 of this BART modeling protocolwere calculated consistentwith the method used by Southern Company to derive these emissions for Toxics Release Inventory (TRI) purposes. This method is documented in a report titled EstimatingTotal Sulfuric Acid Emissions from Stationary Power Plants: Revision 3 (2005) prepared by Keith Harrison and Dr. Larry Monroe (SouthemCompany Services) and EdwardCichanowicz (Consultant). The approach described in this report assumes that H2S04emissions released from the stack are proportional to SO2emissions from combustion and are dependent on the fuel type and the removal of H2S04by downstream equipment (i.e., ESP and air heater). Since this facility contains post-combustionNOx control (SCR), the baselinesulfuric acid emissions estimate accounts for the manufacture of H2S04 through combustion and through further oxidationof SO2in 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 manufactureof H2S04 through injectionof SO3prior 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 calculationsare made. Tables A-1 and A-2 show the resulting H2SO4 emissions calculations for the seasonal (SCR operation) and non-seasonalperiods. 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 

### = EMCombx F2 (technology impact factors for air heater and ESP) ERComb = EMCombx (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 Releasedfrom SCR (ERSCR) ERSCR 

### = [EMSCR 

### - (Ks * B * fs * SNH3)] * F2x where, ERSCR 

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

082506 Miller BART Modeling Protocol.doc A-2 August 2006Ks 

### = 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 conditioningsystem, Ibslhr Ke 

### = Conversion Factor

### = 3,799 

### B = Coal burn in TBtuIhr fe 

### = Operating factor of FGC system, fraction of coal burnedwhen 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 releasedfrom 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 

### = NH3injectionfor dual flue gas conditioningsystem, ppmv at 6% 02,wet (= 0 if no NH3 used) F3 

### =Technology lmpact Factorsfor FGC F2 

### =Technology lmpact Factorsfor 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 2006Table A-2 Plant Miller sulfuric acid calculations (Flue Gas Conditioningand Total)

Case -



# -

- NS 

### - S 

### - NS 

### - S 

### - NS 

## - S 

## - NS 

### - 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 

# I

S= Seasonal ( --F2 

## I 1~~13 lbslhr lbslhr 10.1 Unit 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 EstimatedEmissions ofPrimary TotalCarbonandPrimary Sulfate From Coa/-F/'ed PowerPlants

[The above titled paper is included as a separate document along with this site specific BART modeling protocol. This paper was preparedfor 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 Iin 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 NPTDAT input Used F 

### 36 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 200i
i. 0 

### c7 0CALPUFF Model Input

### tiroiiy 2: Technical t3gtions

# I CALPUFF McddItlput Group ?: Species List-Chemist~y 6jstEons. b 

### IY 0

### utp111 

### 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 25 1

### 4; 153 223



### -


## ..

i I LCC 9 

### 3 

### 9 Y LON 571,:~ 33N L.5 

### N NWS-83

238 UT'd O 0



### -

I 

### I Usei Defined User Defined User Defiried Use- Defired User Defined Ssmpl ng yida not ~,sed Ssmplng CJ-id is not ~sed Sarnpl ng g;rd a not ~sed - -- Sam~! r,r~ 

### 3-:j :> ~SEA Ssinplng 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 lPRTU 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-otrp6:Sub-Grid 

### Scale Cornptex Tel rain Inputs. Parameters 

## Ifnput Used

Species Default r NHlLL NCTREC MHILL XHILL2M ZHILL2M XCTDMKM VCTDMKM Lornlnems Not set 

### ~nlLnt!461M Phase 2 tieport Not set 

### ~n IW43M Phzse 

### 2 Fieport Not set. 111llfldP.3MPhase 2 Fi~port Not set 

### ~nIWA3M Phase 2 Report Not set 

### ~nIWAZVl 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 Diy Depostion 

### Prt~an~ete~s



# I CALPUFF Moclet Input GI-oap 10: 

### Wet Deposition Palorneters. 

# I REACTR NINT 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 PMC 

### S3A 

### EC 3 

### O@E-05 1 

### CUE-04 EOOE-05 1 00E-04 1 CUE-04 1 COE-04 1COE-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
ICf 2-O Cf. 2 b i, 2E, :?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 NPT2 

### 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 

### XL H3L '24R L 

### i.41

### b1L DXL FPRIMEL



# I CALPLIFF 

### Moclel Input Gro~~lr 17: Discrete Receptor Information 

# I tommerits Use- defined. set to nurr:becofstacks

LIS~C when 

### sexon31 and 

### nc?c seasnna errlsslor rates are cons~dered
See Tsble L- 

### I oi the BART hlodellt~y Repo? '~rsxrces~fc~frc caran-etelsand 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 57613 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'esultl? 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 TOTA

# I POSTUTIL Processor tnprrt Gnoup 

### 2: Species Processing Itiformatictn FANITRATE NH3TYP 

### BCKNH3 1 

# -
, 1



### Y.3

### 5

ASPECO ASPECO ASPECO ASPECO SC! A PktF 

### PfvlC

E

### C 0

-99 concentrst~on f~elds (204 h33 and HY03) lJse monthly a3;e-age Sackg1-oundammanla Fxkc.-aunchH7 set tu 

### Cl 5 in sccw~dance -:;ith 'ViS-AS 311dwce

## 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) LCT 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 

### 06 EEPMF 1 EEPMCSK i16 0 ,:7 

### EES04 3 3 

### EEN03 3 3 EEOC 4 3

C 6KSC)IL 12^1'14C 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

THREWi THRESE3 TERESH2d THRESHN 

### MDAY 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 ENSRtAECOMstaff 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: BestAvailable Retrofit Technology Applicability Analysis BPAnzoco 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 ofthe 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 BARTModeling 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. AdrienneNewton 

### - Page 2 January 3 

### 1,2007

Trinity and 

### BP appreciateyour timely review ofthe enclosedBART ApplicabilityAnalysis for the Decatur Works and your continuedcooperation in working with BART-eligible sources throughoutthe BART evaluation process. If you have any questionsor comments aboutthe information presented in the enclosed report, please do not hesitateto 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 

### 1100Johnson 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 

### REGIONALHAZE

### RULE AND 

### BART REQUIREMENTS



## ......................... 2 1.1.1 DETERMINATION OF 

### BART-ELIGIBILITY



### ......................................................... 

# - 7 

### 1.1.2 ASSESSMENT OF 

### CONTRIBUTION TO 

### VISIBILITY LMPAIRMENT AND 

### BART 7



### ................................................................................................ APPLICABILITY 

# - 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



## .......................................................................... AIRQUALITY 

### 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 

### POSTPROCESSINGMETHODS 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 CALMETPROCESSING 31



### ........................................... 3.3.6 QUALITY ASSURANCE OF 

### CALMETANALYSES 

### 32 CALPUFFMODEL 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 CALPUFFMODELING 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 TrinityEd&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 petrochemicalmanufacturing plant in Decatur, Alabama. The Decatur Works is a major source of air enlissions and operates under a Part 70 (Title V) major source operatingpermit (Air Facility 

### ID No. 712-0002) issued by the Alabama Department of EnvironmentalManagement (ADEM). The facility is considered eligible to be regulated under the Best Available Retrofit Technology (BART)provisions ofthe Regional Haze Rule. This BART Applicability Analysis Report summarizes BP's determination that the Decatur Works should not be subjectto BART because the air quality modeling analyses describedin this report demonstratethat the facility does not contributeto visibility impairment at any federally protected Class 

### I areas.
BP submitted an initial source-specificBART ApplicabilityModeling Protocol on March 31,2006, and subsequently received comments from ADEM on July 31,2006. BP reviewed these comments and provided a response to ADEM on August 25,2006, to clarify certain aspects of the BARTeligible sourceinventory 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 TrachcngProgress under the Regional Haze Rule (EPA-454B-03-004), September 2003. U.S. EPA, 

### Guidancefur- 

### EsiimatirigNatur-a1 Visibility CondifiorzsunderfheRegional Haze Rule (EPA-454B-03-005), October 2003. U. S



### .EPA, 

### Interagency Workgroup onAir QualityModeling (ITFAQM)Phase 

### 2 Sul7z11zar y 

### Report (EPA454lR-98-019),December 1998. U.S. EPA, 

### Guideline 012 

### Air Qualio,Models, 40 CFR

### Part 5 1,

### Appendix W (Revised, November 9,2005). VISTAS,

### Protocol for theApplication ofthe CALPUFFModel for Analjses of BestAvailable Retrofit Technology (BART), Revision 3.2,

### August 31,2006. VISTAS and U.S. EPA, "Q&A for Sourceby SourceBART Rule" (Draft), October 28,2005. ADEM, electroniccommunication to BART-eligible sources,multiple dates.
The 

### VISTASBARTModeling Protocol as revised on August 31,2006, is incorporatedby reference for BP' s source-specificmodeling analyses. The 

### VISTAS BART h4odelingProtocol 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 emissionsfrom BART-eligible emission units and conducting screening and refined modeling analyses using the CALPUFF modeling system and common data resources. BP's analysesgenerally adhere to the recommendations made in the 

### VISTASBARTAdodeling Protocol as described in this report and adapted per 

### ADEM guidanceto the source-specific analysis of visibility impacts attributableto the Decatur Works.


## 1.

## OVERVIEW OF 

## REGIONAL HAZE RULE AND 

## BART REQUIREMENTS
The Regional Haze Rule requires that major sources of visibility-affecting pollutantsbelonging to one or more of 26 specific industrial source categories evaluateBART 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 10micrometersin 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 categoriesthat 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 (includingpetrochenlicals)are one of the listed source categories, and include process units and support facilities that are considered to be part ofmajor Standard Industrial Classification 28 - 

### Chemicalsand Allied Products. BP's Decatur Works has determined that 46 emission units comprise the BART-eligble sourcebecause 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 ofNOx, SO?,and PM,,, and accordingly was evaluated to determine whether the facility is considered exempt from BART. Specificinformation about these emissionunits is provided in Section 2 

### of this BART ApplicabilityAnalysis Report. 

### 1.1.2 ASSESSMENT OF 

### CONTRIBUTION TO 

### VISIBILITY 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 

### VISTASBARTModeliizg 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 screeningand refined analyses to assess whether a BART

### eligible source is subject to BART.


### A BART-eligible source is determined to be subject to BART ifthe 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 averagebasis. 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, specificallyreconmending the CALPUFF modeling system,to quantify the impacts attributable to a single BART-eligible source. Because contributionto visibility impairment is sufficient cause to require a BART determination,0.5 dv is the critical threshold for assessment ofBART 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 attributableto a source relative to estimatednatural background conditions. The background extinction coefficient 

### be,. backmu"* 

### is affectedby various chemical species and the Rayleigh scattering phenomenon and has previouslybeen calculatedas shown in the following equation. where,

bso4

### =~[(NH~)~so~~~(RH) 

# denotesthe ammoniumsulfate concentration b,, =3[h7H4~0,If(Jw [NH,NO, ]denotes the ammoniumnitrate concentration b,, =

## ~[oc] [oC]denotes the concentration of organic carbon b,,, =~[soil] [soil]denotesthe concentration of finesoils b,, =0.6[~oarse 

### ass] [coarseMass]denotes the concentration of coarse dusts b, = 1 O[EC] [EC]denotes the concentration of elemental carbon b,,, = ~~~l~i~h scattering 0 Mm-' bydefault) Rayleigh Scatteringis scattering dueto air molecules 

### f(RH

### )=Relative Humidity Function 

### [ ]=Concentration in pg/m3 

### More recently, the Interagency Monitoring ofProtected Visual Environments (IMPROVE) workgroup has proposed a more robust equation for calculating background visibility, as described in detail in a report entitled "Revised MROVEAlgorithm for Estimating Light Extinction from Particle Speciation~ata."'The updated algorithm,which has been



### BP Decatur Works BART Applicability Analysis 

### 3 Trinity Consultants

### approvedby the IMPROVE Steering Committeeand is currently undergoingpeer review, provides a more refined calculation by includingvisibility 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 modelingresults using both the default and the newly revised IMPROVE light extinction formula. Values for the parameters listed above specific to the natural background conditionsat the Class I 

### areas consideredin 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 ofthe revised IMPROVE equation are provided in Section 3.5 of this report. Particulate speciesthat 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 SO2and 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 theRegional Haze Rule. Table 2-1, Attachment A, September 2003, EPA-454lB-03-005. 

### BP Decatur Works BART ApplicabilityAnalysis 4 

### Trinity Consultants40, =3[@% SO,

## lf(m

bN03 = 3[m4N031f(m) b, =~[SOA] bPMF = 1[pMd b,, = O.~[PMC] b,, = 1O[EC] bN, =0.33[~0,] f (RH) =Relative Humidity Function 

### [ 

### ]=Concentrationin pg/rn3 [(NH, 

### )z~~,] denotes the ammonium sulfateconcentration [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 concentrationof coarse PM [EC]denotes the concentration of elemental carbon [NO,] denotes the concentration of nitrogen dioxide



### BP used screeningand refined modeling techniques as describedin the 

### VISTAS BART Modeling Protocol to detennine whether BART-eligible operationsat the Decatur Works contribute to visibility impairment at any Class 

### I areas. The 

### VISTASBARTModelilig Protocol specifiesthat all Class 

### I areas within 

### 300 

### km of a BART-eligible source must be evaluated to determinewhether the source contributes to visibility impairment. Table 

### 1-1 summarizes the distances separatingBP's Decatur Works from all Class 

### I areas within the VISTAS 

### region and 

### adjacent states. Consistent with the 

### VISTASBARTModeling Protocol, only those Class 

### I areas within 

### 300 km 

### were considered furtherin 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)



### BP Decatur Works BART Applicability Analysis 

### 5 Trinity Consultants

## 1.2 

## ORGANIZATION OF 

## BART APPLICABILITY ANALYSIS 

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

A 

### Section 

### 2 describesthe BART-eligible emission units at the Decatur Works and the emission rates modeled in the BART Applicability Analysis.

A 

### Section 

### 3 describesthe 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 describesthe results ofthe screening modeling analyses.

A 

### Section 

### 5 describesthe results ofthe 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 appendicesto this report. Appendix A 

### contains sample model and postprocessing input and output files used for BP's analysisofthe Decatur Works. Appendix B presents a comparative analysis demonstrating the explicit modeling approachused in CALPUFF. Electronic copies of model input and output files are provided on electronicmedia accompanyingthis BART Applicability Analysis Report, a file index for which is presented in '4ppendix C.

BP Decatur Works BART ApplicabilityAnalysis 8 

### Trinity Consultants

### This section ofthe BART ApplicabilityAnalysis Report describes the emission units that comprise the BART-eligible source at BP's Decatur Works. Emissions and exhaust characteristicsof each emission unit are quantifiedto 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 emissionsfrom each unit. Emissionsin 

### bold font indicate changes from the original 

### BP BART Applicability ModelingProtocol afier a closerreview 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 HPA Catox Scrubber Caroh Furnace Storage Silo Vent Scrubber T-761 MAH Tower Boiler kAB 4302 T-741 MA Tower Acenc Acid Scrubber Catoa Scrubber BlowerVent HP.4 LPA T-741 M.4 Tower Condensate Storage Silo Baghouse Crystallizer Scrubber Vent Feed Slurry Dm Dper\'en1 Scrubber Sll05 storage2 AmCenmfuge 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 5110Baghousc 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 despand operation 2. Systemconstas of I0 silos of similardespand apciation 3 Systemconsists of I0silos of s~milar deslp and opermon


### BP Decatur Works BART Applicability Analysis 

### 9 Trinity Consultants

### Note that the original protocol referred to a list of49 

### 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 eligibilityrequirementsbecause 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 maxinlumheat input capacity less than 250 

### MMBtuIhr. These boilers currently have the capability to combust process by-products as an alternative fuel; however, combustion ofthese fuels is not routine. BP submitted a major modification permit application to ADEM 

### to make enforceablein the Title V 

### permit that by-product fuels from the chemical process will not be fired in these boilers under separatecover on Au~st 16, 2006. Therefore,these units were removed from the BART-eligible source inventory describedin Table 2-1 and are not considered further in this BART ApplicabilityAnalysis.
Revisions to the emissionsin Table 2-1 are primarily due to a review of the appropriateAP-42 emission factors. The changein total potential emissions reflects the cumulative changes of each unit, as well as the removal ofthe three boilers that are not integralto the process. The initial BP Applicability ModelingProtocol did not take credit for the Low-NOxburner 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-NOxburners 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 #AB4302 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 1007 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 guaranteeof 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 compliancetest 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) ofNOx, SO2,and PMlO, which are considered visibility-affectingpollutants. Note that many ofthe otherwise BART-eligible emission units have potential emissions only of volatile organic compounds (VOC), which VISTAS and 

### ADEM have determined are not visibilityaffectingpollutants for the purposes of BART applicability analyses. Section 4.1.3 ofthe T/ISTAS

BP Decatur Works BART Applicability Analysis 10 Trinity Consultants

### BARTModeliiig Protocol describes the regional modeling analyses showing that cumulativeVOC emissionsdo 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 ofall VOC emissions fioni all point sources tlzrougl7outthe VISTASdomain was thus determined to be less than 0.5 

### dv (compared to annual average natural background) at eveq?ClassI area in the VISTASdomain and in adjacent States. It follo~)s that the inzpactofanji 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 inzpairnzentand do not need to be included in B.4RT analj~ses.
As a result of this determination, 19ofthe otherwiseBART-eligible emission units operatedby 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 LoadingDock, the PX flare, three goupsof 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 VISTASBARTModeling Protocol specifiesthe following hierarchy of information resources to establish the maximum actual 24-hour average emission rate for BART applicability modeling over the prior three-to-fiveyear 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 representativeperiod

A 

### Facility stack test emissions

A 

### Potential to emit

A 

### Permit allowable emissions

A 

### Emissionsfactors from 

### U.S. 

### EPAAP-42 sourceprofiles
BP used a combination ofrepresentative stack test data, potential emissionsbased 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

BP Decatur Works BART Applicability Analysis 11 Trinity Consultants

### years. Table 2-3 

### summarizesthe emissionrates from each BART-eligible emissionsunit 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 ScrubberVent Feed Sluny Drum Dryer Vent Scrubber Silos Storage Atm CentrifugeHold Tank Vent EB-I0I 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 MMBTUihrReboiler PX Flare (KM-503) Crystallizer ScrubberX'ent Feed SlurryDrum Dryer Vent Scrubber Silos Storage 

### 24-HourAverage 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 ofPIC is estimatedbased on SO2emissions with 5% are conservativelyassumed to be sulfates. For natural assumed to be converted to PIC. BP may refine these assumptionsupon further analyses.



### .4s stated above, emissionsfrom Boiler 4302 represent maximum actual emissionsbased 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 combustionand natural gas combustion in Boiler4302 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 ifthat fuel has not been used in the most recent 3 or 

### 5 year period)." However, the natural gas combustion results provide a true indicationof BP's visibility impact under normal steady-state operationsbecause the facility does not typically burn fuel oil 

### in Boiler 4302. BP reviewed daily records ofhourly 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 ApplicabilityAnalysis 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 ofprimary 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 streambe 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 efzciencyor ex-tinctioncoefjcient, and ranges fi-omvalues of 

### 0.6 m21gfor coarse particulate matter to 10m2igfor 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 ofparticle 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/ISTASBART

### 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. Thisboiler 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 ofAP-4L4 Similarly, BP used AP-42 speciationprofiles 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 guidancefor the miscellaneous process vents and material handling sources. Default speciation profiles compiledby 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 filterablePM emissions, with one exception.'
While few site-specific data are available to estimate speciated emissions, BP has reviewed what data
are availableto 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 settingregulatory emission hitsand are provided here solely as the best estimated data for a scientific analysis ofpotential 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 emissionsfromthe Decatur Works' BART-eligible sources result from combustionoperations. Similarly, SO2emissionsemanate 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 ofthe primary SO2emissions unless an emission factor has otherwise been published. Because of the condensablenature 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 emissionscan 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 ofAirPollutant Emission Factors, .4P-42,Fzjrh Edition, VolumeI: Chapter 1.3,Fuel 

### Oil Conzbustion,Table 1.3-5, September 1998.
ASthe 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 BART Applicability Analysis 14 Trinity Consultants