12.42
Problem 1. (20 points) – Ambient Concentration Conversion At one location, the ambient concentration of NO2 was 50 g/m3 when the ambient pressure was 0.98 atmosphere and temperature was 0 C. Question: What is the equivalent NO2 concentration in g/m3 at 1 atmosphere and 25 C? Problem 2. (20 points) – Air Concentration Calculations The particulate matter (PM) in a stack gas area was 0.045 grains/dry standard cubic foot (dscf). The oxygen concentration in the stack gas was 7% by volume. Question: What is the PM concentration at 3% oxygen? Problem 3. (20 points) - Emission Calculations A stack gas flowing at 80 m3/min (at T = 25 C and 1 atmosphere) contains approximately 75% nitrogen, 5% oxygen, 8% water vapor, and 12% carbon dioxide. Questions: a.What is the molecular weight for the stack gas? b.If the stack gas contains 650 ppm sulfur dioxide, what is the sulfur dioxide emission rate from the stack in kg/day? Problem 4. (20 points) – Emission Calculations Given: Tank Dimensions: Shell Height – 25 feet Shell Diameter – 15 feet Maximum Liquid Height – 25 feet Average Liquid Height – 18 feet Capacity – 35,000 gallons Contents – Diesel Fuel (Fuel Oil #2) Annual Throughput – 750,000 gallons (distributed evenly throughout year) Shell Color – White (Good Condition) Roof Color – White (Good Condition) Cone Roof – 1.5 feet in height Location – San Antonio, Texas Calculate emissions from a vertical fixed roof diesel storage tank using TANKS. Please print out the calculation report from the TANKS program. Note: The US EPA TANKS Windows-based program is available at the following web site: https://www3.epa.gov/ttnchie1/software/tanks/ Problem 5. (20 points) – Emission Calculations Given: Location – San Antonio, Texas Shell Diameter – 25 feet Capacity –75,000 gallons Annual Throughput – 1,500,000 gallons (distributed evenly throughout year) Contents – Gasoline RVP 7 Internal Shell Condition – Light Rust Paint Color – White Paint Condition – Good Roof Type – Pontoon Fittings – Typical Construction - Welded Primary Seal Type – Liquid-mounted Secondary Seal Type - Rim-mounted Question: Calculate emissions from an external floating roof gasoline storage tank with TANKS. Please print out the calculation report from the TANKS program Emission Quantification BasicsQuantify the emission rates (including short‐term and long‐term rates, e.g., lb/hr, kg/hr, metric tons per year, tons per year) and other emission characteristics (e.g., emission pattern, stack parameters) of air pollutants (e.g., SO2, NOX, PM/PM10/PM2.5, CO, VOC, etc.) from an emission source.Objective:to provide the most accurate estimate of emissions based on the available dataWhere assumptions must be made to quantify emission rates, err on the side of protecting public health and welfare (conservative). Source: U.S. EPA, EIIP, Volume II: Chapter 1: Introduction to Stationary Point Source Emission Inventory Development, www.epa.gov/ttn/chief/eiip, 5/31/2001 National Emissions Inventory (NEI)A comprehensive and detailed estimate of air emissions of criteria pollutants, precursors, and hazardous air pollutants from air emissions sources. The NEI is released every three years based primarily upon data provided by State, Local, and Tribal air agencies for sources in their jurisdictions and supplemented by data developed by the US EPA. Typical Policy Making Process Based on Source Emissions Emission Quantification Methods Emission QuantificationBasic Equation:Emission Rate = Pollutant Concentration * Flow RateWhere : Emission Rate in mass/time (e.g., lb/hr)Pollution Concentration in mass/volume (e.g., lb/ft3)Flow Rate in volume/time (e.g., ft3/hr) Key Steps in Emission QuantificationStep 1: Identify and characterize the emission sources Understand the process that emits pollutantsIdentify emission sources and pollutants from the processStep 2: Determine proper methodology and/or emission factors for each sourceStep 3: Collect necessary data Step 4: Quantify emissionsStep 5: Organize and document data for emission reports Know Your ProcessRaw Materials, Energy & ResourcesShippingHandlingStorageDistributionManufacturingTreatingMixingReactingProductsDistribution StorageHandling ShippingWastesStorageHandlingDisposalShipping Know Your ProcessCauses of EmissionsWhat you get is what you usedVOC emissions from solvent usagePM10emissions from raw material handlingVOC emissions from storage tanksWhat you get is not what you usedEmissions from chemical reactionsCombustion products Source CharacteristicsPoint, area, or fugitive emissionsContinuous or batch operationsContinuous emissionsBatch emissionsBatch operation emissionsFlashing or blowdown emissionsPurge emissionsStart‐up, shutdown, or maintenance emissionsControlled or uncontrolled emissions Typical Point Source Data in Emissions InventoryEmission rateOperation days/hoursSeasonal dataAssociated material usage or production ratesCalculation methodologyControl equipmentUncontrolled emission dataSource ID and codesSource coordinatesSource parameters (e.g., stack diameter, height, exit velocity, exit temperature etc.)Annual ReportOne Time Data Emission QuantificationMeasurement TechniquesContinuous emission monitoring (CEM)Parametric emissions monitoring (PEM)Periodic monitoringSource testing –sampling and analysisFugitive emission monitoring Emission QuantificationEstimation MethodsEmission factors:EPA published factors: AP‐42, FIRE, etc.Industry developed factorsPredictive models: TANKS, WATER9, etc.Estimation based on engineering judgementMaterial balance (also called: mass balance) Source: U.S. EPA, EIIP, Volume II: Chapter 1: Introduction to Stationary Point Source Emission Inventory Development, www.epa.gov/ttn/chief/eiip, 5/31/2001 Emission Factor MethodAn emission factor (mass emission per unit activity level) is an estimate of the pollutant emission from an emission source as a function of a measurable activity associated with the release of that pollutant.Estimating emissions using emission factors (e.g., EPA AP‐42) is inexpensive and can provide results that are typically adequate for air permitting purposes. Emission Factor MethodEmission Rate = Emission Factor Activity LevelExample: A gas‐fired industrial boiler emits NOx at an emissionfactor of 140 lbsper MMscfnatural gas burned. In 2004, the boiler used 40,000 scf/hron average. As such, the lb/hr NOx emission rate from the boiler is:Emissions NOx= 140 lbs/mmscf0.04 mmscf/hr= 5.6 lbsNOx / hr Engineering CalculationsEstimate the emissions of a process using physical principles such as diffusion, heat and mass transfer, and fluid flow.“Engineering judgment” are usually not very accurate. Material BalanceUtilizes the conservation of mass to estimate emissions assuming that no mass of the pollutant being estimated is created or destroyed.Most suitable for non‐combustion processes (e.g., degreasers, paint spray booths)Emissions =Material In ‐Material Out (in non‐air streams) Source TestingEstimates emissions by measuring the concentration of a pollutant in a process flow and the flow rate:Emissions = Concentration Flow RateThe most accurate method for emission estimation. Emissions from Combustion Sources Typical Combustion SourcesBoiler and heatersIncineratorsInternal combustion enginesTurbinesFlaresOpen burning sources Typical Fuel TypesCoal Fuel oil Petroleum gasesNatural gasWastes and recycled materials Air Emissions from Boilers at Power Plant Typical Emission Factors (EF)Fuel heating value based factor:lb/MMBtu heat‐inputFuel usage based factor:Solid or liquid fuel: lb/tonGaseous fuel: lb/scf(i.e., standard cubic foot)Air Emissions = EF Activity Level Example of Using Emission FactorsCalculate NOx, CO, and PM emissions from refinery fuel gas (RFG) fired heater with Low NOxburners: RFG Heating Value: 636.3 Btu/scfAnnual Average Heating Rate: 31.2 MMBtu/hr Example of Using Emission FactorsAP‐42 Emission Factors for natural gas fired heaters: Tables 1.4‐1 and 1‐4.2 for small boilers (<100 mmbtu/hr) (7/98 edition)emission factors: efnox= 50 lb/mmscf (“d” grade)efco= 84 lb/mmscf (“b” grade)efpm= 7.6 lb/mmscf (“d” grade)note: these emission factors are based on heating value of 1,020 btu/dscf for natural gas as noted in the ap-42 document example of using emission factorssolution:convert ap‐42 efxto lb/mmbtuefnox= (50 lb/mmscf) /(1,020 mmbtu/mmscf)= 0.049020 lb/mmbtuefco= 84 lb/mmscf/(1,020 mmbtu/mmscf)= 0.082353 lb/mmbtuefpm= 7.6 lb/mmscf/(1,020 mmbtu/mmscf)= 0.007451 lb/mmbtu example of using emission factorsemission calculation:air emission = ef activity levelactivity level = 31.2 mmbtu/hraenox= 0.049020 lb/mmbtu31.2 mmbtu/hr= 1.529 lb/hraeco= 0.082353 lb/mmbtu31.2 mmbtu/hr= 2.569 lb/hraepm= 0.007451 lb/mmbtu31.2 mmbtu/hr= 0.232 lb/hr emission estimate correctioncorrection to dry gas flowoften humidity is presented as wet bulk temperature.with the wet bulk and gas temperature (dry bulk temperature), a psychrometric chart can be used to obtain %moisture.flow)gaswet (100%moisture-100flowgasdry emission estimate correctioncorrection to standard or permit conditions:standard pressure ‐1 atmosphere (760 mmhg)standard temperature –varies. epa has used: 60 °f and 20 °c (68 °f)gas flow rate @standard conditions = (gas flow @measured) (pm/ps) (ts/tm)subscript m = measured; s = standard conditions emission estimate correctioncorrection for %o2often needed for referencing combustion source emissions.for boilers, referencing at 3% o2(consistent with the near stoichiometric conditions)for combustion turbines, referencing at 15% o2(consistent with the high excess air flow)2222%om9.20%oref9.20]%oconc[m]%oconc[ref emission calculation for rule complianceexample: turbine burning fuel oil must meet noxemission standard of 65 ppmd at 15% o2. the stack testing result shows that the noxconcentrationin thefluegasis 90 ppmd at 12% o2. does the nox concentration comply with the emission standard? yes, you are okcorrect 90 ppmd at 12% excess o2to 15% excess o2 as follows:ppmdppmdppmd657.59%12%9.20%15%9.2090 fugitive emissions from equipment leaks common equipment that may leakpumpsvalvescompressorspressure relief valvesconnectors and flangesagitatorsopen‐ended linessampling connector common sourcesrefinerypetroleum marketing terminalsoil and gas exploration and productionssynthetic organic chemical manufacturing industry (socmi) equipment leakepa guidance on equipment leak:protocol for equipment leak emission estimatesequipment in specific servicesgaslight liquidheavy liquid uncontrolled fugitive emissionswhere:etoc= emission rate of toc from all equipment in the stream of a given equipment type (kg/hr);fa= applicable average emission factor for the equipment type (kg/hr per source);wftoc= average weight fraction of toc in the stream;n = number of pieces of the applicable equipment type in the stream. example calculation using average leak factorleak rate = 0.00597 kg/hr/component× 10= 0.0597 kg/hrat the scomi, there are 10 valves in gas service : emissions from organic material handling processes know your materialsliquids pure compounds: benzene, acetone mixture: e.g., gasoline, paint thinner, waste solventsaqueous liquids:chemicals soluble in water: alcohol, ammoniachemicals slightly soluble in water: benzene, h2smixture with liquid, water, solid ‐paints know your materials (cont’d)material compositionmaterial properties (e.g, density, mw,vp)usage/disposalstorage conditionsshipping method(s) and quantitiessolidswateror exemptvoc/hap know your chemicalsbasic chemical physical propertiesfor a reportable chemicalmolecular weightvapor pressureboiling pointliquid densityhenry’s law constants solubility in water calculating vapor pressureantoine equation to calculate vapor pressure (p) in mm‐hg at a temperature of concern for a pure chemical in liquid phase:where a, b, and c = antoine coefficientt = temperature in c ctbaplog)( mixed solvent vapor pressure raoult’slawis commonly used to calculate the vapor pressure of a solvent mixture with known liquid compositions.the mole fraction of the component in the liquid (xi) multiplied by thevapor pressure of the pure component (ps,i) is equal to the partial pressure (pi) of that component:iisixpp, mixed solvent vapor pressureiiiiimwmwxivppwhere:wi= weight for component i; andmi= molecular weight for componentithe mole fraction (xi) of a liquid component is determined by:the total vapor pressure (pv) of the mixture is calculated from the sum of the partial pressures of all components in the gas phase: vapor molecule weight calculationiiippyiivymmthe vapor molecular weight (mv) is determined from the individual component molecular weight (mi) and the vapor mole fraction (yi) by:where the vapor mole fraction (yi) is determined from the partial vapor pressure by: storage tank emissions storage tank topicsstorage tank typesemissions for each tank typetank and liquid parameters tanks 4.09d software types of storage tanksfixed roof (i.e., volume) vertical fixed roof horizontal fixed roofexternal floating roof (efr)internal floating roof (ifr)pressurized vessel vertical fixed roof tankscylindrical shell with a permanent roofcone‐shaped, dome‐shaped, or flat rooffreely‐vented or equipped with a pressure vent emissionsworking losses due to tank filling and emptyingbreathing losses resulting from changes in temperature and barometric pressure horizontal fixed mmbtu/hr)="" (7/98="" edition)emission="" factors:="" efnox="50" lb/mmscf="" (“d”="" grade)efco="84" lb/mmscf="" (“b”="" grade)efpm="7.6" lb/mmscf="" (“d”="" grade)note:="" these="" emission="" factors="" are="" based="" on="" heating="" value="" of="" 1,020="" btu/dscf="" for="" natural="" gas="" as="" noted="" in="" the="" ap-42="" document="" example="" of="" using="" emission="" factorssolution:convert="" ap‐42="" efxto="" lb/mmbtuefnox="(50" lb/mmscf)="" (1,020="" mmbtu/mmscf)="0.049020" lb/mmbtuefco="84" lb/mmscf/(1,020="" mmbtu/mmscf)="0.082353" lb/mmbtuefpm="7.6" lb/mmscf/(1,020="" mmbtu/mmscf)="0.007451" lb/mmbtu="" example="" of="" using="" emission="" factorsemission="" calculation:air="" emission="EF" activity="" levelactivity="" level="31.2" mmbtu/hraenox="0.049020" lb/mmbtu31.2="" mmbtu/hr="1.529" lb/hraeco="0.082353" lb/mmbtu31.2="" mmbtu/hr="2.569" lb/hraepm="0.007451" lb/mmbtu31.2="" mmbtu/hr="0.232" lb/hr="" emission="" estimate="" correctioncorrection="" to="" dry="" gas="" flowoften="" humidity="" is="" presented="" as="" wet="" bulk="" temperature.with="" the="" wet="" bulk="" and="" gas="" temperature="" (dry="" bulk="" temperature),="" a="" psychrometric="" chart="" can="" be="" used="" to="" obtain="" %moisture.flow)gaswet="" (100%moisture-100flowgasdry="" emission="" estimate="" correctioncorrection="" to="" standard="" or="" permit="" conditions:standard="" pressure="" ‐1="" atmosphere="" (760="" mmhg)standard="" temperature="" –varies.="" epa="" has="" used:="" 60="" °f="" and="" 20="" °c="" (68="" °f)gas="" flow="" rate="" @standard="" conditions="(Gas" flow="" @measured)="" (pm/ps)="" (ts/tm)subscript="" m="measured;" s="standard" conditions="" emission="" estimate="" correctioncorrection="" for="" %o2often="" needed="" for="" referencing="" combustion="" source="" emissions.for="" boilers,="" referencing="" at="" 3%="" o2(consistent="" with="" the="" near="" stoichiometric="" conditions)for="" combustion="" turbines,="" referencing="" at="" 15%="" o2(consistent="" with="" the="" high="" excess="" air="" flow)2222%om9.20%oref9.20]%oconc[m]%oconc[ref="" emission="" calculation="" for="" rule="" complianceexample:="" turbine="" burning="" fuel="" oil="" must="" meet="" noxemission="" standard="" of="" 65="" ppmd="" at="" 15%="" o2.="" the="" stack="" testing="" result="" shows="" that="" the="" noxconcentrationin="" thefluegasis="" 90="" ppmd="" at="" 12%="" o2.="" does="" the="" nox="" concentration="" comply="" with="" the="" emission="" standard?="" yes,="" you="" are="" okcorrect="" 90="" ppmd="" at="" 12%="" excess="" o2to="" 15%="" excess="" o2="" as="" follows:ppmdppmdppmd657.59%12%9.20%15%9.2090="" fugitive="" emissions="" from="" equipment="" leaks="" common="" equipment="" that="" may="" leakpumpsvalvescompressorspressure="" relief="" valvesconnectors="" and="" flangesagitatorsopen‐ended="" linessampling="" connector="" common="" sourcesrefinerypetroleum="" marketing="" terminalsoil="" and="" gas="" exploration="" and="" productionssynthetic="" organic="" chemical="" manufacturing="" industry="" (socmi)="" equipment="" leakepa="" guidance="" on="" equipment="" leak:protocol="" for="" equipment="" leak="" emission="" estimatesequipment="" in="" specific="" servicesgaslight="" liquidheavy="" liquid="" uncontrolled="" fugitive="" emissionswhere:etoc="Emission" rate="" of="" toc="" from="" all="" equipment="" in="" the="" stream="" of="" a="" given="" equipment="" type="" (kg/hr);fa="Applicable" average="" emission="" factor="" for="" the="" equipment="" type="" (kg/hr="" per="" source);wftoc="Average" weight="" fraction="" of="" toc="" in="" the="" stream;n="Number" of="" pieces="" of="" the="" applicable="" equipment="" type="" in="" the="" stream.="" example="" calculation="" using="" average="" leak="" factorleak="" rate="0.00597" kg/hr/component×="" 10="0.0597" kg/hrat="" the="" scomi,="" there="" are="" 10="" valves="" in="" gas="" service="" :="" emissions="" from="" organic="" material="" handling="" processes="" know="" your="" materialsliquids="" pure="" compounds:="" benzene,="" acetone="" mixture:="" e.g.,="" gasoline,="" paint="" thinner,="" waste="" solventsaqueous="" liquids:chemicals="" soluble="" in="" water:="" alcohol,="" ammoniachemicals="" slightly="" soluble="" in="" water:="" benzene,="" h2smixture="" with="" liquid,="" water,="" solid="" ‐paints="" know="" your="" materials="" (cont’d)material="" compositionmaterial="" properties="" (e.g,="" density,="" mw,vp)usage/disposalstorage="" conditionsshipping="" method(s)="" and="" quantitiessolidswateror="" exemptvoc/hap="" know="" your="" chemicalsbasic="" chemical="" physical="" propertiesfor="" a="" reportable="" chemicalmolecular="" weightvapor="" pressureboiling="" pointliquid="" densityhenry’s="" law="" constants="" solubility="" in="" water="" calculating="" vapor="" pressureantoine="" equation="" to="" calculate="" vapor="" pressure="" (p)="" in="" mm‐hg="" at="" a="" temperature="" of="" concern="" for="" a="" pure="" chemical="" in="" liquid="" phase:where="" a,="" b,="" and="" c="Antoine" coefficientt="temperature" in="" c="" ctbaplog)(="" mixed="" solvent="" vapor="" pressure="" raoult’slawis="" commonly="" used="" to="" calculate="" the="" vapor="" pressure="" of="" a="" solvent="" mixture="" with="" known="" liquid="" compositions.the="" mole="" fraction="" of="" the="" component="" in="" the="" liquid="" (xi)="" multiplied="" by="" thevapor="" pressure="" of="" the="" pure="" component="" (ps,i)="" is="" equal="" to="" the="" partial="" pressure="" (pi)="" of="" that="" component:iisixpp,="" mixed="" solvent="" vapor="" pressureiiiiimwmwxivppwhere:wi="Weight" for="" component="" i;="" andmi="Molecular" weight="" for="" componentithe="" mole="" fraction="" (xi)="" of="" a="" liquid="" component="" is="" determined="" by:the="" total="" vapor="" pressure="" (pv)="" of="" the="" mixture="" is="" calculated="" from="" the="" sum="" of="" the="" partial="" pressures="" of="" all="" components="" in="" the="" gas="" phase:="" vapor="" molecule="" weight="" calculationiiippyiivymmthe="" vapor="" molecular="" weight="" (mv)="" is="" determined="" from="" the="" individual="" component="" molecular="" weight="" (mi)="" and="" the="" vapor="" mole="" fraction="" (yi)="" by:where="" the="" vapor="" mole="" fraction="" (yi)="" is="" determined="" from="" the="" partial="" vapor="" pressure="" by:="" storage="" tank="" emissions="" storage="" tank="" topicsstorage="" tank="" typesemissions="" for="" each="" tank="" typetank="" and="" liquid="" parameters="" tanks="" 4.09d="" software="" types="" of="" storage="" tanksfixed="" roof="" (i.e.,="" volume)="" vertical="" fixed="" roof="" horizontal="" fixed="" roofexternal="" floating="" roof="" (efr)internal="" floating="" roof="" (ifr)pressurized="" vessel="" vertical="" fixed="" roof="" tankscylindrical="" shell="" with="" a="" permanent="" roofcone‐shaped,="" dome‐shaped,="" or="" flat="" rooffreely‐vented="" or="" equipped="" with="" a="" pressure="" vent="" emissionsworking="" losses="" due="" to="" tank="" filling="" and="" emptyingbreathing="" losses="" resulting="" from="" changes="" in="" temperature="" and="" barometric="" pressure="" horizontal="">