site-wide modeling for mss

Site-Wide Modeling Site-Wide Modeling for MSSfor MSS

Robert Opiela, Team LeaderRobert Opiela, Team Leader

Air Dispersion Modeling TeamAir Dispersion Modeling Team

TCEQ, Air Permits DivisionTCEQ, Air Permits Division

Austin, TexasAustin, Texas

October 16, 2007October 16, 2007

IntroductionIntroduction

• Define conceptsDefine concepts

• Clarify expectationsClarify expectations

• Provide examplesProvide examples

ApplicabilityApplicability

• MSS related projectsMSS related projects

• Flexible permitsFlexible permits

• Permits with operational flexibilityPermits with operational flexibility

New ConceptsNew Concepts

• ActivityActivity– Facility emissions authorized for specific Facility emissions authorized for specific

activityactivity

• Activity not associated with a facilityActivity not associated with a facility– Emissions of same pollutant from all Emissions of same pollutant from all

activities are evaluatedactivities are evaluated

Not So New Concept Not So New Concept (1)(1)

• Modeling scenarioModeling scenario– Representation of activities from a single Representation of activities from a single

sourcesource

• ExamplesExamples– Load analyses for EGULoad analyses for EGU– Tank working losses and breathing lossesTank working losses and breathing losses– Short-term analysis separate from annualShort-term analysis separate from annual

Implementation in Implementation in ModelingModeling

• Demonstrating worst-case scenarioDemonstrating worst-case scenario– Represent all applicable operating Represent all applicable operating

scenarios (production and MSS scenarios (production and MSS activities) activities)

– Key representations included in permit Key representations included in permit conditionsconditions


• Generic modelingGeneric modeling– Model each source/source group at 1 Model each source/source group at 1

lb/hrlb/hr

– Report results (µg/mReport results (µg/m33 per lb/hr) for each per lb/hr) for each source/source groupsource/source group

– Use ONE model input file, pleaseUse ONE model input file, please


• Determining culpable sourcesDetermining culpable sources– Provides information on source(s) Provides information on source(s)

driving worst-case scenariodriving worst-case scenario

– Allows focus on limited number of Allows focus on limited number of sourcessources

• Determines site baseline concentrationsDetermines site baseline concentrations


• Emission rate to ESL ratio (E/ESL)Emission rate to ESL ratio (E/ESL)– Evaluate site-wide or Evaluate site-wide or

– Sum source by source for all sourcesSum source by source for all sources


• Determining limiting pollutantDetermining limiting pollutant– If this pollutant acceptable, all pollutants If this pollutant acceptable, all pollutants

acceptableacceptable

• Determining limiting emission ratesDetermining limiting emission rates– Demonstrates pollutant emission rate by Demonstrates pollutant emission rate by

source that would be acceptable source that would be acceptable


• Continuous ActivityContinuous Activity– Theoretically could operate 8760 Theoretically could operate 8760

hours/year but practically could nothours/year but practically could not

– Operates from hour-to-hour for many Operates from hour-to-hour for many hours/year during any 8760 hours/yearhours/year during any 8760 hours/year

– Operates from hour-to-hour for many Operates from hour-to-hour for many hours/year on a certain schedulehours/year on a certain schedule


• Batch ActivitiesBatch Activities– Activity starts and finishes within a few Activity starts and finishes within a few

hourshours

– Significant time between activitiesSignificant time between activities

– Limited number of activities per yearLimited number of activities per year

ExpectationsExpectations

• Document all steps in your analysisDocument all steps in your analysis

• Substantiate all claims and Substantiate all claims and representationsrepresentations

• Provide technical justifications for all Provide technical justifications for all assumptions and selectionsassumptions and selections

Example (1)Example (1)

• Continuous production and one MSS Continuous production and one MSS activityactivity– Is MSS activity separate source from all Is MSS activity separate source from all

production sources?production sources?

– In either case, all emissions considered In either case, all emissions considered in annual analysisin annual analysis

Example (1) Example (1) ImplementationImplementation

• Case of MSS simultaneous with Case of MSS simultaneous with productionproduction– Model production as one source groupModel production as one source group

– Model MSS activity as one source groupModel MSS activity as one source group

– Model using ALL groupModel using ALL group


• Case of MSS not simultaneous with all Case of MSS not simultaneous with all productionproduction– Model all production activities as one Model all production activities as one

scenarioscenario

– Model MSS and simultaneous production Model MSS and simultaneous production sources as separate groups in 2nd scenariosources as separate groups in 2nd scenario

– Could model MSS and all production Could model MSS and all production together as a short-cut, only if below together as a short-cut, only if below thresholdthreshold


• Analyzing exceedances in either caseAnalyzing exceedances in either case– Consider production and MSS hours of Consider production and MSS hours of

operation separately to adjust number operation separately to adjust number of exceedancesof exceedances

– Could consider only production hours of Could consider only production hours of operation as a short-cutoperation as a short-cut


• Annual concentrationsAnnual concentrations– Model production as one source groupModel production as one source group

– Model MSS as one source group at Model MSS as one source group at maximum hour emission ratemaximum hour emission rate

– Add the production concentrations to Add the production concentrations to N/8760 times the sum of the N highest N/8760 times the sum of the N highest MSS predicted concentrations; N is MSS MSS predicted concentrations; N is MSS hourshours


• Annual concentrations short-cutsAnnual concentrations short-cuts– Add N/8760 times MSS GLCAdd N/8760 times MSS GLCmaxmax to to

production GLCproduction GLCmaxmax, or, or

– Add MSS GLCAdd MSS GLCmaxmax to production GLC to production GLCmaxmax

Example (2)Example (2)

• Continuous and batch production Continuous and batch production activities and multiple MSS activitiesactivities and multiple MSS activities– Much more complicated, but don’t make Much more complicated, but don’t make

more complicated than you need tomore complicated than you need to

– Recommend you submit a detailed Recommend you submit a detailed modeling protocol; coordinate with us modeling protocol; coordinate with us FIRST before you start modelingFIRST before you start modeling


• Helpful hintsHelpful hints– Follow general ADMT guidance; pre-Follow general ADMT guidance; pre-

coordinate deviations from general coordinate deviations from general guidanceguidance

– Be ready to perform generic modeling of Be ready to perform generic modeling of ALL sourcesALL sources

– Use MAXIFILE option with source groupsUse MAXIFILE option with source groups


• First conduct generic modelingFirst conduct generic modeling– Use 1 lb/hr for each source/source groupUse 1 lb/hr for each source/source group– Use 1 model input fileUse 1 model input file– Use 1 PLOTFILEUse 1 PLOTFILE– Use 1 averaging time (1-hour or annual)Use 1 averaging time (1-hour or annual)


• Import PLOTFILE into a spreadsheetImport PLOTFILE into a spreadsheet– Select fixed record length optionSelect fixed record length option– Parse the columns properlyParse the columns properly– Start on first row of data, skip the Start on first row of data, skip the

headerheader

• Sort data in spreadsheetSort data in spreadsheet– Sort by source group, x, ySort by source group, x, y– Delete all header linesDelete all header lines


• Import spreadsheet into database Import spreadsheet into database programprogram– Create a table of the spreadsheet dataCreate a table of the spreadsheet data– Run query to reformat dataRun query to reformat data– Export query results into another Export query results into another

spreadsheetspreadsheet– Results are the unit concentrationsResults are the unit concentrations


• Determine maximum unit Determine maximum unit concentrationsconcentrations– Use MAX function for each source groupUse MAX function for each source group– Determine worst case sourceDetermine worst case source– Can apply E/ESL for that source, maybeCan apply E/ESL for that source, maybe– Can use for generic method 1Can use for generic method 1

• If you pass, you’re doneIf you pass, you’re done


• Determine worst case scenarioDetermine worst case scenario– Provide data from generic modelingProvide data from generic modeling– Analyze data from generic modelingAnalyze data from generic modeling– Specify the operational conditionsSpecify the operational conditions– Propose physical or operational limitsPropose physical or operational limits


• Refine with generic method 2Refine with generic method 2– Create worksheet with emission ratesCreate worksheet with emission rates

•List pollutantList pollutant

•List ESLList ESL

•List emission rate by source groupList emission rate by source group


• Refine with generic method 2Refine with generic method 2– Apply unit concentration to E/ESLApply unit concentration to E/ESL

•For each source groupFor each source group

•Sum contributions from all source groupsSum contributions from all source groups

•Determine the maximumDetermine the maximum

•Results are in multiples of the ESLResults are in multiples of the ESL


• Further RefinementFurther Refinement– Pollutant specific modelingPollutant specific modeling– Use the MAXIFILE optionUse the MAXIFILE option

•For the ALL source groupFor the ALL source group

•For culpable source groupsFor culpable source groups

•Use an appropriate thresholdUse an appropriate threshold


• Further RefinementFurther Refinement– Adjusting hours of exceedanceAdjusting hours of exceedance

•Consider hours of culpable sourcesConsider hours of culpable sources– If hours fewer than hours of exceedancesIf hours fewer than hours of exceedances– Scale based on hours if operating hours are Scale based on hours if operating hours are

frequentfrequent

•Consider operation scheduleConsider operation schedule– Daytime only or nighttime onlyDaytime only or nighttime only– Hours between activitiesHours between activities

SummarySummary• Be clear on concepts discussed earlierBe clear on concepts discussed earlier

• Ask questions if you are unclear or unsureAsk questions if you are unclear or unsure

• Follow ADMT guidanceFollow ADMT guidance

• Document everything you didDocument everything you did

• Minimize the modeling and modeling filesMinimize the modeling and modeling files

QuestionsQuestions

site-wide modeling for mss

Documents

production activities

production concentrations

mss hoursexample

scenariomodel mss

productionmodel production

continuous production

source groupmodel mss

caseconsider production